{"id":1853,"date":"2026-08-11T07:26:12","date_gmt":"2026-08-11T07:26:12","guid":{"rendered":"https:\/\/haktak.com\/?p=1853"},"modified":"2026-08-11T07:26:15","modified_gmt":"2026-08-11T07:26:15","slug":"thermal-grease-for-power-modules","status":"publish","type":"post","link":"https:\/\/haktak.com\/vi\/thermal-grease-for-power-modules\/","title":{"rendered":"Keo t\u1ea3n nhi\u1ec7t cho m\u00f4-\u0111un c\u00f4ng su\u1ea5t: H\u01b0\u1edbng d\u1eabn l\u1ef1a ch\u1ecdn"},"content":{"rendered":"<div class=\"product\"><div class=\"product\">\n<p class=\"wp-block-paragraph\">M\u1ee1 t\u1ea3n nhi\u1ec7t cho c\u00e1c m\u00f4-\u0111un c\u00f4ng su\u1ea5t l\u1ea5p \u0111\u1ea7y nh\u1eefng kho\u1ea3ng tr\u1ed1ng si\u00eau nh\u1ecf gi\u1eefa t\u1ea5m \u0111\u1ebf c\u1ee7a m\u00f4-\u0111un v\u00e0 b\u1ed9 t\u1ea3n nhi\u1ec7t ho\u1eb7c t\u1ea5m ngu\u1ed9i l\u00e0m m\u00e1t b\u1eb1ng ch\u1ea5t l\u1ecfng. B\u1eb1ng c\u00e1ch thay th\u1ebf kh\u00f4ng kh\u00ed b\u1ecb m\u1eafc k\u1eb9t b\u1eb1ng v\u1eadt li\u1ec7u d\u1eabn nhi\u1ec7t t\u1ed1t h\u01a1n, m\u1ee1 gi\u00fap gi\u1ea3m \u0111i\u1ec7n tr\u1edf nhi\u1ec7t ti\u1ebfp x\u00fac v\u00e0 h\u1ed7 tr\u1ee3 nhi\u1ec7t tho\u00e1t kh\u1ecfi IGBT, c\u00e1c m\u00f4-\u0111un SiC MOSFET v\u00e0 c\u00e1c m\u00f4-\u0111un c\u00f4ng su\u1ea5t th\u00f4ng minh. S\u1ea3n ph\u1ea9m ph\u00f9 h\u1ee3p kh\u00f4ng \u0111\u01a1n gi\u1ea3n l\u00e0 lo\u1ea1i m\u1ee1 c\u00f3 gi\u00e1 tr\u1ecb W\/mK cao nh\u1ea5t. \u0110\u00f3 l\u00e0 lo\u1ea1i m\u1ee1 t\u1ea1o th\u00e0nh m\u1ed9t l\u1edbp ti\u1ebfp x\u00fac m\u1ecfng, ph\u1ee7 k\u00edn v\u00e0 \u1ed5n \u0111\u1ecbnh trong c\u1ee5m l\u1eafp r\u00e1p th\u1ef1c t\u1ebf.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"912\" height=\"595\" src=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/02\/image-5.png\" alt=\"thermal-grease-for-power-modules\" class=\"wp-image-1341\" srcset=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/02\/image-5.png 912w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/02\/image-5-300x196.png 300w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/02\/image-5-768x501.png 768w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/02\/image-5-600x391.png 600w\" sizes=\"(max-width: 912px) 100vw, 912px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">S\u1ef1 kh\u00e1c bi\u1ec7t n\u00e0y r\u1ea5t quan tr\u1ecdng. M\u1ed9t v\u1eadt li\u1ec7u t\u1ed1t v\u1eabn c\u00f3 th\u1ec3 ho\u1ea1t \u0111\u1ed9ng k\u00e9m khi b\u1ed9 t\u1ea3n nhi\u1ec7t kh\u00f4ng ph\u1eb3ng, l\u1edbp v\u1eadt li\u1ec7u \u0111\u01b0\u1ee3c ph\u1ee7 qu\u00e1 d\u00e0y, tr\u00ecnh t\u1ef1 si\u1ebft v\u00edt l\u00e0m cong t\u1ea5m \u0111\u1ebf ho\u1eb7c m\u1ee1 b\u1ecb d\u1ecbch chuy\u1ec3n trong qu\u00e1 tr\u00ecnh chu k\u1ef3 nhi\u1ec7t. N\u00f3i c\u00e1ch kh\u00e1c, m\u00f4-\u0111un, m\u1ee1, b\u1ec1 m\u1eb7t l\u00e0m m\u00e1t, ph\u1ea7n c\u1ee9ng l\u1eafp \u0111\u1eb7t v\u00e0 quy tr\u00ecnh thi c\u00f4ng ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t h\u1ec7 th\u1ed1ng th\u1ed1ng nh\u1ea5t.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">H\u01b0\u1edbng d\u1eabn n\u00e0y gi\u1ea3i th\u00edch c\u00e1ch l\u1ef1a ch\u1ecdn h\u1ec7 th\u1ed1ng \u0111\u00f3. N\u1ed9i dung bao g\u1ed3m c\u00e1c \u0111\u1eb7c t\u00ednh v\u1eadt li\u1ec7u c\u1ea7n so s\u00e1nh, ki\u1ec3m so\u00e1t \u0111\u1ed9 d\u00e0y \u0111\u01b0\u1eddng keo th\u1ef1c t\u1ebf, in stencil, c\u00e1c d\u1ea1ng h\u01b0 h\u1ecfng th\u01b0\u1eddng g\u1eb7p, c\u00e1c l\u1ef1a ch\u1ecdn thay th\u1ebf, ti\u00eau chu\u1ea9n v\u00e0 th\u1ea9m \u0111\u1ecbnh s\u1ea3n xu\u1ea5t. Lu\u00f4n xem h\u01b0\u1edbng d\u1eabn l\u1eafp \u0111\u1eb7t c\u1ee7a nh\u00e0 s\u1ea3n xu\u1ea5t m\u00f4-\u0111un l\u00e0 c\u0103n c\u1ee9 cu\u1ed1i c\u00f9ng \u0111\u1ed1i v\u1edbi h\u00ecnh h\u1ecdc v\u00e0 y\u00eau c\u1ea7u si\u1ebft c\u1ed1 \u0111\u1ecbnh c\u1ee7a m\u00f4-\u0111un.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Does Thermal Grease Do in a Power Module Assembly?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Thermal grease does not cool a module by itself. It improves contact at the module-to-cooler interface. Even machined metal surfaces contain peaks, valleys and slight shape errors. When two dry surfaces are clamped together, those irregularities trap insulating air. Grease wets the surfaces and fills the small voids, creating a more continuous path for heat.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">The heat path from the semiconductor junction to the coolant or air<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Heat begins at the semiconductor junction. It then travels through the die attach, substrate, internal conductors and baseplate, where present. From there, it crosses the thermal interface material and enters a heat sink or cold plate. Finally, it moves into air or coolant.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The grease occupies only one thin part of that path, but it can become a bottleneck. Think of it like a gasket between two sections of pipe. The gasket is short, yet a poor fit can restrict the whole flow.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Engineers commonly track several resistance terms:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Rth(j-c)<\/strong>: junction-to-case thermal resistance inside the module.<\/li>\n\n\n\n<li><strong>Rth(c-h)<\/strong>: case-to-heat-sink resistance, strongly influenced by the interface.<\/li>\n\n\n\n<li><strong>Rth(h-a)<\/strong> or cooler-to-fluid resistance: heat rejection from the cooling hardware.<\/li>\n\n\n\n<li><strong>Rth<\/strong><strong>(j-a)<\/strong>: the complete junction-to-ambient path.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Grease selection mainly affects <strong>Rth(c-h)<\/strong>, but a temperature problem should still be investigated across the whole stack. A better TIM cannot rescue an undersized cold plate or poor coolant flow.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Baseplate and baseplate-less modules need different thinking<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A conventional IGBT module may have a metal baseplate that spreads heat and provides a mounting surface. Some newer SiC modules use thinner baseplates, exposed ceramic structures or baseplate-less designs to reduce thermal mass and internal resistance. These designs can be more sensitive to local pressure, flatness and insulation requirements.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Do not assume thermal grease provides electrical isolation. Many greases are electrically non-conductive, but the thin grease layer is not automatically a certified dielectric barrier. If isolation is part of the safety design, verify the module construction and use a qualified insulation solution.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ec3 c\u00f3 c\u00e1i nh\u00ecn t\u1ed5ng quan h\u01a1n v\u1ec1 m\u1ee1 t\u1ea3n nhi\u1ec7t, mi\u1ebfng \u0111\u1ec7m, gel v\u00e0 c\u00e1c v\u1eadt li\u1ec7u kh\u00e1c <a href=\"https:\/\/haktak.com\/vi\/thermal-interface-materials\/\">v\u1eadt li\u1ec7u d\u1eabn nhi\u1ec7t giao di\u1ec7n<\/a>, h\u00e3y b\u1eaft \u0111\u1ea7u b\u1eb1ng vi\u1ec7c x\u00e1c \u0111\u1ecbnh khe h\u1edf th\u1ef1c t\u1ebf v\u00e0 c\u1ea5u tr\u00fac \u0111i\u1ec7n tr\u01b0\u1edbc khi l\u1ef1a ch\u1ecdn d\u1ea1ng v\u1eadt li\u1ec7u.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">B\u1eaft \u0111\u1ea7u t\u1eeb b\u1ec1 m\u1eb7t ti\u1ebfp x\u00fac, kh\u00f4ng ph\u1ea3i con s\u1ed1 \u0111\u1ed9 d\u1eabn nhi\u1ec7t<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"611\" src=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-1024x611.webp\" alt=\"B\u1eaft \u0111\u1ea7u t\u1eeb b\u1ec1 m\u1eb7t ti\u1ebfp x\u00fac, kh\u00f4ng ph\u1ea3i con s\u1ed1 \u0111\u1ed9 d\u1eabn nhi\u1ec7t\" class=\"wp-image-1795\" srcset=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-1024x611.webp 1024w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-300x179.webp 300w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-768x458.webp 768w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-18x12.webp 18w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics-600x358.webp 600w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/power-electronics.webp 1200w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed9 d\u1eabn nhi\u1ec7t m\u00f4 t\u1ea3 m\u1ee9c \u0111\u1ed9 d\u1ec5 truy\u1ec1n nhi\u1ec7t qua to\u00e0n b\u1ed9 kh\u1ed1i v\u1eadt li\u1ec7u. \u0110\u00e2y l\u00e0 th\u00f4ng s\u1ed1 h\u1eefu \u00edch, nh\u01b0ng kh\u00f4ng ph\u1ea3n \u00e1nh \u0111\u1ed9 ti\u1ebfp x\u00fac b\u1ec1 m\u1eb7t, chi\u1ec1u d\u00e0y cu\u1ed1i c\u00f9ng ho\u1eb7c s\u1ef1 l\u00e3o h\u00f3a. \u0110i\u1ec7n tr\u1edf nhi\u1ec7t giao di\u1ec7n \u1edf c\u1ea5p \u0111\u1ed9 c\u1ee5m l\u1eafp r\u00e1p l\u00e0 t\u1ed5ng c\u1ee7a \u0111i\u1ec7n tr\u1edf nhi\u1ec7t trong kh\u1ed1i v\u1eadt li\u1ec7u v\u00e0 \u0111i\u1ec7n tr\u1edf ti\u1ebfp x\u00fac t\u1ea1i c\u1ea3 hai b\u1ec1 m\u1eb7t. M\u1ee1 c\u00f3 \u0111\u1ed9 d\u1eabn nhi\u1ec7t \u1edf m\u1ee9c v\u1eeba ph\u1ea3i nh\u01b0ng lan th\u00e0nh m\u1ed9t l\u1edbp m\u1ecfng, li\u00ean t\u1ee5c c\u00f3 th\u1ec3 cho hi\u1ec7u qu\u1ea3 t\u1ed1t h\u01a1n s\u1ea3n ph\u1ea9m c\u00f3 \u0111\u1ed9 d\u1eabn nhi\u1ec7t cao h\u01a1n t\u00ednh theo W\/mK nh\u01b0ng v\u1eabn d\u00e0y ho\u1eb7c \u0111\u1ec3 l\u1ea1i c\u00e1c kho\u1ea3ng r\u1ed7ng.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi m\u1ed9t l\u1edbp \u0111\u1ed3ng nh\u1ea5t \u0111\u01b0\u1ee3c \u0111\u01a1n gi\u1ea3n h\u00f3a:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>R = t \/ (k x A)<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u1ede \u0111\u00e2u:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>R<\/strong> l\u00e0 \u0111i\u1ec7n tr\u1edf nhi\u1ec7t kh\u1ed1i.<\/li>\n\n\n\n<li><strong>t<\/strong> l\u00e0 \u0111\u1ed9 d\u00e0y \u0111\u01b0\u1eddng keo.<\/li>\n\n\n\n<li><strong>k<\/strong> l\u00e0 \u0111\u1ed9 d\u1eabn nhi\u1ec7t.<\/li>\n\n\n\n<li><strong>A<\/strong> l\u00e0 di\u1ec7n t\u00edch ti\u1ebfp x\u00fac hi\u1ec7u d\u1ee5ng.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00f4ng th\u1ee9c n\u00e0y h\u1eefu \u00edch, nh\u01b0ng c\u00e1c m\u1ed1i n\u1ed1i th\u1ef1c t\u1ebf ph\u00e1t sinh th\u00eam \u0111i\u1ec7n tr\u1edf ti\u1ebfp x\u00fac. \u0110\u1ed9 nh\u00e1m b\u1ec1 m\u1eb7t, kh\u1ea3 n\u0103ng l\u00e0m \u01b0\u1edbt, \u00e1p su\u1ea5t v\u00e0 h\u00ecnh d\u1ea1ng ch\u1ea5t \u0111\u1ed9n \u0111\u1ec1u \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn ph\u1ea7n \u0111i\u1ec7n tr\u1edf b\u1ed5 sung n\u00e0y. V\u00ec v\u1eady, kh\u00f4ng n\u00ean ch\u1ec9 s\u1eed d\u1ee5ng gi\u00e1 tr\u1ecb \u0111\u1ed9 d\u1eabn nhi\u1ec7t trong b\u1ea3ng d\u1eef li\u1ec7u k\u1ef9 thu\u1eadt \u0111\u1ec3 d\u1ef1 \u0111o\u00e1n nhi\u1ec7t \u0111\u1ed9 m\u1ed1i n\u1ed1i.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">S\u1ef1 ph\u00e2n bi\u1ec7t gi\u1eefa <a href=\"https:\/\/haktak.com\/vi\/thermal-conductivity-vs-thermal-impedance-tim-selection\/\">\u0111\u1ed9 d\u1eabn nhi\u1ec7t v\u00e0 t\u1ed5ng tr\u1edf nhi\u1ec7t<\/a> \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch trong giai \u0111o\u1ea1n s\u00e0ng l\u1ecdc ban \u0111\u1ea7u.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Datasheet term<\/strong><\/td><td><strong>Nh\u1eefng g\u00ec n\u00f3 n\u00f3i v\u1edbi b\u1ea1n<\/strong><\/td><td><strong>What it does not tell you<\/strong><\/td><td><strong>How to use it<\/strong><\/td><\/tr><tr><td>Thermal conductivity, W\/mK<\/td><td>Bulk heat-transfer potential<\/td><td>Final contact quality or bond line<\/td><td>Compare materials tested by a clear, comparable method<\/td><\/tr><tr><td>Thermal resistance, K\/W<\/td><td>Temperature rise per heat flow for a stated sample or assembly<\/td><td>Performance at another area, thickness or pressure<\/td><td>Ch\u1ec9 s\u1eed d\u1ee5ng v\u1edbi h\u00ecnh h\u1ecdc v\u00e0 c\u00e1c \u0111i\u1ec1u ki\u1ec7n \u0111\u00e3 n\u00eau<\/td><\/tr><tr><td>Tr\u1edf kh\u00e1ng nhi\u1ec7t, K cm2\/W<\/td><td>\u0110i\u1ec7n tr\u1edf chu\u1ea9n h\u00f3a theo di\u1ec7n t\u00edch trong c\u00e1c \u0111i\u1ec1u ki\u1ec7n x\u00e1c \u0111\u1ecbnh<\/td><td>Nhi\u1ec7t \u0111\u1ed9 ch\u00ednh x\u00e1c c\u1ee7a m\u00f4-\u0111un khi kh\u00f4ng c\u00f3 d\u1eef li\u1ec7u h\u1ec7 th\u1ed1ng<\/td><td>So s\u00e1nh c\u00e1c ti\u1ebfp gi\u00e1p \u1edf \u00e1p su\u1ea5t v\u00e0 \u0111\u1ed9 d\u00e0y th\u1ef1c t\u1ebf<\/td><\/tr><tr><td>\u0110\u1ed9 nh\u1edbt<\/td><td>Kh\u1ea3 n\u0103ng ch\u1ed1ng ch\u1ea3y trong qu\u00e1 tr\u00ecnh th\u1eed nghi\u1ec7m \u0111\u00e3 n\u00eau<\/td><td>Kh\u1ea3 n\u0103ng nh\u1ea3 kh\u1ecfi stencil, \u0111\u1ed9 s\u1ee5t ho\u1eb7c hi\u1ec7n t\u01b0\u1ee3ng di chuy\u1ec3n l\u00e2u d\u00e0i c\u1ee7a ri\u00eang v\u1eadt li\u1ec7u<\/td><td>\u0110\u1ed1i chi\u1ebfu v\u1edbi nhu c\u1ea7u in, \u0111\u1ecbnh l\u01b0\u1ee3ng v\u00e0 thao t\u00e1c<\/td><\/tr><tr><td>Nhi\u1ec7t \u0111\u1ed9 ho\u1ea1t \u0111\u1ed9ng<\/td><td>D\u1ea3i nhi\u1ec7t \u0111\u1ed9 s\u1eed d\u1ee5ng \u0111\u01b0\u1ee3c c\u00f4ng b\u1ed1<\/td><td>\u0110\u1ed9 \u1ed5n \u0111\u1ecbnh l\u00e2u d\u00e0i theo ch\u1ebf \u0111\u1ed9 chu k\u1ef3 ngu\u1ed3n c\u1ee7a b\u1ea1n<\/td><td>Y\u00eau c\u1ea7u b\u1eb1ng ch\u1ee9ng v\u1ec1 qu\u00e1 tr\u00ecnh l\u00e3o h\u00f3a v\u00e0 x\u00e1c nh\u1eadn c\u1ee5m l\u1eafp r\u00e1p<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">B\u1ea3y y\u1ebfu t\u1ed1 khi l\u1ef1a ch\u1ecdn m\u1ee1 t\u1ea3n nhi\u1ec7t cho m\u00f4-\u0111un c\u00f4ng su\u1ea5t<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">M\u1ee1 t\u1ea3n nhi\u1ec7t cho m\u00f4-\u0111un c\u00f4ng su\u1ea5t t\u1ed1i \u01b0u l\u00e0 v\u1eadt li\u1ec7u \u0111\u1ea1t \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 y\u00eau c\u1ea7u, \u0111\u1ed3ng th\u1eddi c\u00f3 quy tr\u00ecnh s\u1ea3n xu\u1ea5t \u1ed5n \u0111\u1ecbnh v\u00e0 tu\u1ed5i th\u1ecd ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c. Vi\u1ec7c l\u1ef1a ch\u1ecdn c\u1ea7n k\u1ebft h\u1ee3p tr\u1edf kh\u00e1ng nhi\u1ec7t t\u1ea1i b\u1ec1 m\u1eb7t ti\u1ebfp x\u00fac, \u0111\u1ed9 d\u00e0y l\u1edbp keo c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c, t\u00ednh l\u01b0u bi\u1ebfn, \u0111\u1ed9 \u1ed5n \u0111\u1ecbnh nhi\u1ec7t \u0111\u1ed9, kh\u1ea3 n\u0103ng ch\u1ed1ng di chuy\u1ec3n, t\u00ednh t\u01b0\u01a1ng th\u00edch v\u00e0 ki\u1ec3m so\u00e1t ngu\u1ed3n cung. M\u1ed9t ch\u1ec9 s\u1ed1 n\u1ed5i b\u1eadt kh\u00f4ng th\u1ec3 thay th\u1ebf s\u1ef1 c\u00e2n b\u1eb1ng n\u00e0y.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. Tr\u1edf kh\u00e1ng nhi\u1ec7t \u1edf c\u1ea5p \u0111\u1ed9 c\u1ee5m l\u1eafp r\u00e1p<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Y\u00eau c\u1ea7u d\u1eef li\u1ec7u v\u1ec1 tr\u1edf kh\u00e1ng nhi\u1ec7t ho\u1eb7c \u0111i\u1ec7n tr\u1edf nhi\u1ec7t \u0111\u01b0\u1ee3c \u0111o \u1edf \u0111\u1ed9 d\u00e0y, \u00e1p su\u1ea5t v\u00e0 nhi\u1ec7t \u0111\u1ed9 c\u1ee5 th\u1ec3. \u0110\u1ed3 g\u00e1 th\u1eed nghi\u1ec7m v\u00e0 \u0111\u1ed9 ho\u00e0n thi\u1ec7n b\u1ec1 m\u1eb7t \u0111\u1ec1u \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn k\u1ebft qu\u1ea3, v\u00ec v\u1eady h\u00e3y so s\u00e1nh c\u00e1c \u0111i\u1ec1u ki\u1ec7n t\u01b0\u01a1ng \u0111\u01b0\u01a1ng. N\u1ebfu c\u00e1c nh\u00e0 cung c\u1ea5p s\u1eed d\u1ee5ng c\u00e1c ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c nhau, th\u1ee9 h\u1ea1ng c\u00f3 th\u1ec3 ph\u1ea3n \u00e1nh s\u1ef1 kh\u00e1c bi\u1ec7t c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p c\u0169ng nhi\u1ec1u nh\u01b0 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa c\u00e1c h\u1ee3p ch\u1ea5t.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">M\u1ed9t th\u1eed nghi\u1ec7m s\u00e0ng l\u1ecdc th\u1ef1c t\u1ebf s\u1eed d\u1ee5ng c\u00e1c b\u1ec1 m\u1eb7t kim lo\u1ea1i \u0111\u1ea1i di\u1ec7n v\u00e0 nhi\u1ec1u chi\u1ec1u d\u00e0y l\u1edbp li\u00ean k\u1ebft. Th\u1eed nghi\u1ec7m ph\u00ea duy\u1ec7t cu\u1ed1i c\u00f9ng s\u1eed d\u1ee5ng m\u00f4-\u0111un c\u00f4ng su\u1ea5t v\u00e0 b\u1ed9 l\u00e0m m\u00e1t th\u1ef1c t\u1ebf. Ghi l\u1ea1i nhi\u1ec7t \u0111\u1ed9 ch\u1ea5t l\u00e0m m\u00e1t ho\u1eb7c b\u1ed9 t\u1ea3n nhi\u1ec7t, nhi\u1ec7t \u0111\u1ed9 v\u1ecf m\u00f4-\u0111un v\u00e0 ch\u1ec9 b\u00e1o nhi\u1ec7t \u0111\u1ed9 \u0111i\u1ec7n c\u00f3 \u0111\u1ed9 l\u1eb7p l\u1ea1i khi c\u00f3 th\u1ec3.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u0110\u1ed9 d\u00e0y l\u1edbp li\u00ean k\u1ebft c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">M\u1ee1 t\u1ea3n nhi\u1ec7t cho hi\u1ec7u qu\u1ea3 t\u1ed1t nh\u1ea5t khi \u0111\u1ee7 m\u1ecfng \u0111\u1ec3 h\u1ea1n ch\u1ebf \u0111i\u1ec7n tr\u1edf nhi\u1ec7t kh\u1ed1i, \u0111\u1ed3ng th\u1eddi \u0111\u1ee7 d\u00e0y \u0111\u1ec3 l\u1ea5p \u0111\u1ea7y bi\u1ebfn thi\u00ean th\u1ef1c t\u1ebf c\u1ee7a b\u1ec1 m\u1eb7t. \u0110\u1ed9 d\u00e0y l\u1edbp li\u00ean k\u1ebft c\u00f3 th\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c ph\u1ee5 thu\u1ed9c v\u00e0o:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u0110\u1ed9 ph\u1eb3ng c\u1ee7a m\u00f4-\u0111un v\u00e0 b\u1ec1 m\u1eb7t l\u00e0m m\u00e1t.<\/li>\n\n\n\n<li>\u0110\u1ed9 nh\u00e1m v\u00e0 \u0111\u1ed9 l\u01b0\u1ee3n s\u00f3ng c\u1ee7a b\u1ec1 m\u1eb7t.<\/li>\n\n\n\n<li>Mounting pressure and screw locations.<\/li>\n\n\n\n<li>Grease viscosity, yield stress and filler particle size.<\/li>\n\n\n\n<li>Stencil pattern, deposited volume and squeeze flow.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c <a href=\"https:\/\/haktak.com\/vi\/how-bond-line-thickness-affects-thermal-performance\/\">effect of bond line thickness on thermal performance<\/a> is often larger than buyers expect. Do not choose a nominal coating thickness before studying the mounted joint.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. Viscosity, thixotropy and stencil printability<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Viscosity is only a snapshot of flow resistance. Thixotropy describes how a material changes under shear and then rebuilds after the force is removed. A printable grease should fill the stencil openings, release cleanly, keep its pattern before mounting and spread under clamping without running everywhere.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For automated dispensing, check pressure stability, bead continuity, nozzle size, filler settling and startup after idle time. For stencil printing, check squeegee speed, angle, stencil thickness, aperture geometry and release. A material can have excellent thermal data and still be a headache on the line. That happens more than anyone likes to admit.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. Operating and peak temperature range<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Power modules experience steady heat, short overloads and repeated power cycles. A broad datasheet temperature range does not prove stable viscosity or interface resistance over years of cycling.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Define the real profile:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Normal case and cooler temperature.<\/li>\n\n\n\n<li>Maximum continuous temperature.<\/li>\n\n\n\n<li>Short-duration peak temperature.<\/li>\n\n\n\n<li>Startup and shutdown frequency.<\/li>\n\n\n\n<li>Temperature swing and dwell time.<\/li>\n\n\n\n<li>Expected service life.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Request post-aging data where possible. Then repeat the thermal measurement after cycling, not just before it.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. Pump-out, dry-out, oil bleed and volatility<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">These terms describe different problems:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>H\u00fat ch\u1ea5t th\u1ea3i<\/strong> is material movement caused by repeated expansion, contraction and pressure changes.<\/li>\n\n\n\n<li><strong>L\u00e0m kh\u00f4<\/strong> is the loss or redistribution of carrier fluid until the interface becomes filler-rich and less compliant.<\/li>\n\n\n\n<li><strong>R\u00f2 r\u1ec9 d\u1ea7u<\/strong> is visible separation or migration of the liquid phase.<\/li>\n\n\n\n<li><strong>Volatility<\/strong> is the loss of lower-molecular-weight components, accelerated by heat or low pressure.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Look for stable coverage around hot areas and edges after cycling. A grease that starts with low resistance but migrates away from the active region is not a low-resistance solution in service.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. Electrical and chemical compatibility<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Confirm whether the grease is electrically insulating, slightly conductive or designed only for thermal contact. Also review its interaction with coatings, plastics, labels, seals, connectors and cleaning agents. Silicone oil migration can be unacceptable near optical surfaces, relay contacts, painting or bonding operations. In those cases, evaluate a <a href=\"https:\/\/haktak.com\/vi\/thermal-grease\/silicone-free-thermal-grease\/\">d\u1ea7u m\u1ee1 nhi\u1ec7t kh\u00f4ng ch\u1ee9a silicone<\/a> or another controlled-chemistry TIM.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7. Manufacturing and supply controls<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The supplier should support more than a sample syringe. Production planning needs:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Packaging suited to printing or dispensing equipment.<\/li>\n\n\n\n<li>Storage temperature and shelf life.<\/li>\n\n\n\n<li>Conditioning, mixing or de-airing instructions.<\/li>\n\n\n\n<li>Batch traceability and certificate data.<\/li>\n\n\n\n<li>Lot-to-lot rheology and thermal controls.<\/li>\n\n\n\n<li>Change-notification policy.<\/li>\n\n\n\n<li>Technical support for stencil and validation trials.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Engineering question<\/strong><\/td><td><strong>Property to review<\/strong><\/td><td><strong>R\u1ee7i ro quy tr\u00ecnh<\/strong><\/td><td><strong>Recommended evidence<\/strong><\/td><\/tr><tr><td>Will the module meet its temperature target?<\/td><td>Thermal impedance at realistic BLT<\/td><td>Datasheet-only selection<\/td><td>Module-to-cooler thermal test<\/td><\/tr><tr><td>Can the layer remain thin and complete?<\/td><td>Rheology, particle size, wetting<\/td><td>Voids or thick areas<\/td><td>Printed mass, thickness and transfer pattern<\/td><\/tr><tr><td>Will it survive cycling?<\/td><td>Pump-out and aging stability<\/td><td>Edge loss or dry zones<\/td><td>Thermal or power cycling plus post-test inspection<\/td><\/tr><tr><td>Can production apply it repeatedly?<\/td><td>Printability or dispensing stability<\/td><td>Lot and operator variation<\/td><td>Capability study using measured deposit mass<\/td><\/tr><tr><td>Is it compatible with the assembly?<\/td><td>Electrical and chemical behavior<\/td><td>Leakage, contamination or coating defects<\/td><td>Compatibility and insulation testing<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">How Thick Should Thermal Grease Be on an IGBT or SiC Power Module?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">There is no universal grease thickness for every IGBT or SiC power module. Many manufacturer examples sit in the tens to low hundreds of micrometres, but the approved value belongs to a specific module, cooler surface and application pattern. Follow the module mounting document, then verify the compressed interface and thermal result.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, Fuji Electric has published guidance around 100 micrometres for selected industrial IGBT modules, including a 100 +\/- 30 micrometre example. Mitsubishi literature includes 50-100 micrometres for some module families, while other families use broader ranges. Microchip has documented a minimum value for a specified module and method. These numbers are examples, not a shared industry rule.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Also distinguish deposited thickness from mounted bond line. A stencil creates a patterned deposit with open spaces. During mounting, grease spreads and the peaks collapse. Measuring only the stencil thickness does not reveal the final interface.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">A simple grease quantity estimate<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For a first estimate:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Mass = coated area x average deposited thickness x density<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Suppose a printed pattern has an effective coated area of 90 cm2, an average deposited thickness of 0.010 cm and a grease density of 2.6 g\/cm3:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Mass = 90 x 0.010 x 2.6 = 2.34 g<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is a starting process quantity, not an approved specification. Pattern openings, squeeze-out and the mounted bond line change the real result. Weighing the module before and after printing is a useful production check because it measures deposited mass more consistently than a casual visual judgement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u00e1c <a href=\"https:\/\/www.fujielectric.com\/products\/semiconductor\/model\/igbt\/mounting\/box\/doc\/pdf\/MT\/MT5Q04137_EN.pdf\" target=\"_blank\" rel=\"noopener\">Fuji Electric mounting instructions<\/a> show why grease thickness, heat-sink flatness, roughness and fastening need to be read together.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Heat-Sink Flatness, Roughness and Mounting Pressure Are Part of TIM Selection<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"661\" src=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-1024x661.png\" alt=\"Heat-Sink Flatness, Roughness and Mounting Pressure Are Part of TIM Selection\" class=\"wp-image-1819\" srcset=\"https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-1024x661.png 1024w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-300x194.png 300w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-768x496.png 768w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-18x12.png 18w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image-600x387.png 600w, https:\/\/haktak.com\/wp-content\/uploads\/2026\/08\/image.png 1120w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The cooling surface can make a suitable grease look bad. Excessive flatness error creates local thick areas or dry contact. Roughness increases the volume needed to fill surface valleys. Uneven fastening changes pressure and may distort the module baseplate. Define these mechanical conditions before locking the grease and stencil.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Flatness and roughness<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Flatness describes the overall shape error across the mounting area. Roughness describes the smaller texture left by machining. Both affect contact, but in different ways. A polished surface can still be bowed, and a flat surface can still be too rough.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Inspect the complete module footprint, not a small convenient patch. Module manufacturers often specify acceptable flatness and roughness for their products. Use their limits rather than copying a number from another module family.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Torque and tightening sequence<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Mounting screws should usually be tightened in progressive steps and in the sequence specified by the module supplier. Pulling one corner fully down before the others can tilt or bend the module, trap grease and produce an uneven bond line.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Control the tool, torque, screw condition, washer stack and seating surface. For prototypes, mark the sequence and record actual torque. It sounds basic, but this is where quiet variation sneaks in.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Contact pattern inspection<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Build sacrificial validation assemblies. Apply the specified pattern, mount the module, then remove it carefully and inspect transfer to both surfaces. Look for uncovered areas, trapped air, edge starvation and excessive squeeze-out.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Combine the visual check with temperature mapping, thermocouples or a module-specific temperature-sensitive electrical parameter. A pretty spread pattern is useful, but the thermal result still decides.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Stencil Printing vs Roller, Spatula and Automated Dispensing<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Stencil printing is widely used for power modules because it controls deposited location and volume across a large baseplate. A module-specific pattern allows grease to spread into a thin layer while leaving routes for air to escape. Rollers and spatulas can work in prototypes, but they create more operator variation. Automated dispensing is useful when the pattern and material are designed together.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why stencil printing appears in OEM guidance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Power modules are larger and mechanically different from desktop processors. A dot or X pattern that looks fine in a hobby video is not a production method for a wide IGBT baseplate.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A stencil can provide:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Repeatable deposited mass.<\/li>\n\n\n\n<li>Controlled keep-out around holes and edges.<\/li>\n\n\n\n<li>Defined islands or tracks for spreading.<\/li>\n\n\n\n<li>Faster inspection and operator training.<\/li>\n\n\n\n<li>A measurable relationship between aperture, stencil thickness and deposit.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">c\u1ee7a Infineon <a href=\"https:\/\/www.infineon.com\/assets\/row\/public\/documents\/60\/42\/infineon-an2006-02-application-of-screen-print-templates-applicationnotes-en.pdf?fileId=db3a304412b407950112b40ed3f71297\" target=\"_blank\" rel=\"noopener\">application note on screen-printing templates<\/a> illustrates the module-specific nature of stencil geometry and process control.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">When another method may be acceptable<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">A roller or controlled spatula can be practical for engineering trials, service work or low-volume builds when the module maker permits it. Dispensing may suit an automated line if the beads merge into full coverage without trapping air. Pre-applied TIM can remove an in-house printing step entirely.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Whichever method is used, define the deposited mass, position, inspection criteria and mounted result. \u201cApply a thin layer\u201d is an instruction, but not yet a process.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Practical production sequence<\/h3>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Inspect the module base and cooling surface for damage or contamination.<\/li>\n\n\n\n<li>Clean both surfaces using approved materials and allow them to dry.<\/li>\n\n\n\n<li>Condition the grease according to its storage and handling instructions.<\/li>\n\n\n\n<li>Align the module-specific stencil or dispensing fixture.<\/li>\n\n\n\n<li>Print or dispense the controlled pattern.<\/li>\n\n\n\n<li>Inspect position, completeness and deposited mass.<\/li>\n\n\n\n<li>Mount the module using the specified screw sequence and torque steps.<\/li>\n\n\n\n<li>Verify transfer pattern and thermal performance on validation units.<\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Ph\u01b0\u01a1ng ph\u00e1p \u1ee9ng d\u1ee5ng<\/strong><\/td><td><strong>Volume control<\/strong><\/td><td><strong>T\u1ed1c \u0111\u1ed9 s\u1ea3n xu\u1ea5t<\/strong><\/td><td><strong>Common risk<\/strong><\/td><td><strong>Ph\u00f9 h\u1ee3p nh\u1ea5t<\/strong><\/td><\/tr><tr><td>Module-specific stencil<\/td><td>High after setup<\/td><td>Cao<\/td><td>Poor release or wrong pattern<\/td><td>S\u1ea3n xu\u1ea5t l\u1eb7p l\u1ea1i<\/td><\/tr><tr><td>Vi\u1ec7c ph\u00e2n ph\u1ed1i t\u1ef1 \u0111\u1ed9ng<\/td><td>High with calibrated equipment<\/td><td>Trung b\u00ecnh \u0111\u1ebfn cao<\/td><td>Bead gaps, air entrapment, filler settling<\/td><td>Flexible automated lines<\/td><\/tr><tr><td>Roller<\/td><td>Trung b\u00ecnh<\/td><td>Trung b\u00ecnh<\/td><td>Operator-dependent thickness<\/td><td>Approved low-volume assembly<\/td><\/tr><tr><td>Spatula or manual spread<\/td><td>Th\u1ea5p \u0111\u1ebfn trung b\u00ecnh<\/td><td>Th\u1ea5p<\/td><td>Uneven coverage and contamination<\/td><td>Prototype or service work<\/td><\/tr><tr><td>Pre-applied TIM<\/td><td>Very high at supplier<\/td><td>High in final assembly<\/td><td>Storage or handling damage<\/td><td>Clean high-volume assembly<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For general handling background, see Haktak&#8217;s guide to <a href=\"https:\/\/haktak.com\/vi\/tips-applying-thermal-grease-how-it-works\/\">applying thermal grease<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Common Thermal Grease Failure Modes in Power Electronics<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Most thermal grease failures are interface failures, not dramatic material breakdowns. The usual signs are rising or inconsistent temperatures, dry-looking regions, edge accumulation, squeeze-out or contamination. The root cause may be the quantity, stencil, surface, mounting process, aging behavior or cooling hardware. Diagnose the evidence before blaming the jar.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Too much grease<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">An overly thick layer adds thermal resistance. It may also squeeze beyond the baseplate, contaminate nearby surfaces or interfere with service. More grease does not mean more cooling. The compound is there to replace air, not to become a thick heat-spreading slab.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Too little grease or incomplete wetting<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Insufficient quantity can leave air pockets, especially over a bowed baseplate or rough cooler. Local dry areas create hot spots even when the average module temperature looks acceptable. Poor stencil release or an interrupted dispensing bead can produce the same symptom.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Pump-out and edge accumulation<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">During every heat-up and cool-down cycle, the module and cooler expand by different amounts. Their small relative movement can push a low-stability grease away from active regions. After many cycles, material may gather near edges while the centre becomes thin or dry.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Dry-out, oil separation and viscosity drift<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Heat can redistribute or remove carrier fluid. The remaining filler-rich layer becomes less able to wet changing surfaces. Oil bleed may also migrate outside the interface. Check mass, appearance and thermal resistance before and after aging.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Poor surface or mounting control<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Variation in flatness, roughness, cleaning, screw torque and stencil alignment often looks like material variation. A good root-cause study compares these records with thermal data by serial number.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Observed symptom<\/strong><\/td><td><strong>Nguy\u00ean nh\u00e2n c\u00f3 kh\u1ea3 n\u0103ng cao<\/strong><\/td><td><strong>Evidence to check<\/strong><\/td><td><strong>Corrective action<\/strong><\/td><\/tr><tr><td>High temperature from first build<\/td><td>Thick bond line, voids or poor cooler<\/td><td>Deposit mass, transfer pattern, flatness<\/td><td>Correct surface or pattern, then retest<\/td><\/tr><tr><td>Large unit-to-unit variation<\/td><td>Manual application or torque variation<\/td><td>Weight, stencil position, torque records<\/td><td>Tighten process controls and train operators<\/td><\/tr><tr><td>Nhi\u1ec7t \u0111\u1ed9 t\u0103ng sau c\u00e1c chu k\u1ef3<\/td><td>Pump-out, dry-out or joint movement<\/td><td>Post-cycle coverage and thermal resistance<\/td><td>Screen a more stable grease or revise mechanics<\/td><\/tr><tr><td>Grease around module edges<\/td><td>Excess volume or squeeze flow<\/td><td>Printed mass and edge pattern<\/td><td>Reduce or redistribute the deposit<\/td><\/tr><tr><td>Coating or contact contamination<\/td><td>Oil bleed or incompatible chemistry<\/td><td>Residue analysis and compatibility test<\/td><td>Use controlled-bleed or silicone-free material<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Thermal Grease vs Phase Change Material, Thermal Pad and Graphite<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Thermal grease is usually strongest at thin, clamped interfaces that need excellent wetting. It is not automatically best for every module. Phase-change materials can simplify handling, pads can bridge larger gaps or provide engineered insulation, and graphite can spread heat laterally. Compare the actual geometry, electrical needs, production flow and life profile.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Lo\u1ea1i TIM<\/strong><\/td><td><strong>Best interface<\/strong><\/td><td><strong>Typical bond line<\/strong><\/td><td><strong>Assembly advantage<\/strong><\/td><td><strong>L\u01b0u \u00fd ch\u00ednh<\/strong><\/td><\/tr><tr><td>Keo t\u1ea3n nhi\u1ec7t<\/td><td>Flat, tightly clamped module-to-cooler joint<\/td><td>R\u1ea5t m\u1ecfng<\/td><td>Excellent wetting and reworkability<\/td><td>Application variation, pump-out and bleed<\/td><\/tr><tr><td>Phase-change material<\/td><td>Thin clamped joint with clean preform or coating<\/td><td>Thin<\/td><td>Controlled placement and low mess<\/td><td>Must reach activation conditions and wet properly<\/td><\/tr><tr><td>Mi\u1ebfng t\u1ea3n nhi\u1ec7t<\/td><td>Larger or tolerance-varying gap<\/td><td>Medium to thick<\/td><td>Clean placement, compliance and insulation options<\/td><td>Higher bulk resistance and compression stress<\/td><\/tr><tr><td>T\u1ea5m than ch\u00ec<\/td><td>Lateral heat spreading or selected thin joints<\/td><td>R\u1ea5t m\u1ecfng<\/td><td>Strong in-plane spreading<\/td><td>Electrical conductivity and limited conformity<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">A <a href=\"https:\/\/haktak.com\/vi\/phase-change-thermal-interface-material\/\">v\u1eadt li\u1ec7u giao di\u1ec7n nhi\u1ec7t chuy\u1ec3n pha<\/a> may be attractive when a clean pre-applied process and stronger resistance to grease migration matter. Validate activation temperature, pressure and surface contact.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Pads are useful when there is a measurable gap or component height variation. They are not direct replacements for a thin grease joint without redesign. Graphite is highly anisotropic: excellent lateral conductivity does not automatically mean low through-plane interface resistance.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Application Examples Across Power Electronics<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Power module grease appears in traction inverters, industrial drives, renewable-energy converters, UPS systems and other high-current equipment. The selection logic is similar, but the dominant stress changes. Automotive systems emphasize severe cycling and contamination control. Industrial systems may prioritize long service, repair and process repeatability. Renewable equipment adds broad ambient conditions and remote operation.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">EV traction inverter and onboard charger<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">An EV inverter may use SiC or IGBT modules mounted to a liquid cold plate. High power density makes a small interface change visible in junction temperature. Qualification should combine coolant conditions, power cycling, vibration and chemical compatibility. The grease must also fit a controlled automotive assembly process.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Industrial motor drive and servo system<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Industrial drives run for long periods and may see dust, vibration and irregular maintenance. Consistent stencil application and stable thermal resistance are often more useful than chasing the highest catalog conductivity. Rework and field replacement procedures should use the same controlled quantity as production.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Solar inverter and energy-storage PCS<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Solar and battery conversion systems experience daily temperature cycles and wide ambient swings. Pump-out and dry-out screening deserve attention. Haktak&#8217;s guide to <a href=\"https:\/\/haktak.com\/vi\/thermal-paste-for-inverters\/\">thermal paste for inverters<\/a> discusses this operating context in more detail.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">UPS, welding and high-power supplies<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">These systems may have high transient loads and forced-air or liquid cooling. Verify the peak case temperature, mounting pressure and cooler capacity. A short overload may be acceptable electrically but still create a severe interface temperature swing.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Testing Standards and a Realistic Qualification Plan<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">No single certificate proves that thermal grease will work beneath a power module. Standard methods provide comparable material data, while the final assembly test proves the interface. A sensible plan moves from datasheet review to controlled material tests, process capability, representative module testing and aging. Re-measure performance after environmental stress.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">ASTM D5470 and TIM property measurement<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/store.astm.org\/standards\/d5470\" target=\"_blank\" rel=\"noopener\">ASTM D5470<\/a> is widely referenced for steady-state thermal transmission properties of thermally conductive materials. It can be used to derive thermal impedance and apparent conductivity under controlled conditions. ASTM also makes clear that an idealized method does not reproduce every real interface. Surface finish, pressure, thickness and specimen preparation still matter.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">JESD51 thermal measurement concepts<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The JEDEC JESD51 family provides semiconductor thermal-characterization concepts and methods. These are useful when planning junction-temperature measurements and thermal networks. They are not a standalone thermal grease certification. Apply the relevant method to the device and test objective.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">IEC 60068 and application-specific environmental tests<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">IEC 60068 methods are commonly used as building blocks for dry heat, damp heat, temperature change, shock and vibration testing. Choose tests that reflect the product environment. Automotive, railway, renewable-energy or customer-specific programs may add their own cycles and acceptance limits.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1ed5ng quan v\u1ec1 Haktak <a href=\"https:\/\/haktak.com\/vi\/common-tim-testing-standards-engineers-should-know\/\">c\u00e1c ti\u00eau chu\u1ea9n ki\u1ec3m tra TIM ph\u1ed5 bi\u1ebfn<\/a> can help teams separate material-property tests from assembly reliability tests.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Recommended qualification ladder<\/h3>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Review documentation.<\/strong> Check TDS, SDS, compliance, storage, shelf life and traceability.<\/li>\n\n\n\n<li><strong>Run controlled TIM tests.<\/strong> Compare candidate materials at multiple relevant bond lines and pressures.<\/li>\n\n\n\n<li><strong>Study the application process.<\/strong> Measure deposited mass, position, repeatability and defects.<\/li>\n\n\n\n<li><strong>Test the representative assembly.<\/strong> Use the real module, cooler, fasteners and coolant or airflow.<\/li>\n\n\n\n<li><strong>Apply environmental stress.<\/strong> Run thermal cycling, power cycling, humidity and vibration as required.<\/li>\n\n\n\n<li><strong>Inspect and re-measure.<\/strong> Compare thermal resistance, coverage, bleed, migration and mechanical condition.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">What to Send a Thermal Grease Supplier<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A useful recommendation starts with assembly information, not a request for \u201cthe highest W\/mK paste.\u201d Share the module, cooler, temperature target, geometry, mounting process, production method and reliability profile. With that context, a supplier can narrow the chemistry and rheology, propose samples and help define a realistic validation plan.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Prepare the following brief:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Power module manufacturer, part number and mounting guide.<\/li>\n\n\n\n<li>Module construction, baseplate size and active heat area.<\/li>\n\n\n\n<li>Heat-sink or cold-plate material, coating, flatness and roughness.<\/li>\n\n\n\n<li>Device loss, coolant or ambient condition and temperature limit.<\/li>\n\n\n\n<li>Maximum allowable interface resistance.<\/li>\n\n\n\n<li>Screw pattern, torque sequence and estimated clamping pressure.<\/li>\n\n\n\n<li>Preferred stencil, printing, dispensing or pre-applied process.<\/li>\n\n\n\n<li>Continuous, peak and cycling temperature profile.<\/li>\n\n\n\n<li>Vibration, humidity, chemicals and service-life expectations.<\/li>\n\n\n\n<li>Electrical insulation and silicone restrictions.<\/li>\n\n\n\n<li>Prototype quantity, annual volume, packaging and traceability needs.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">For applications where a very thin interface is the priority, Haktak can evaluate a <a href=\"https:\/\/haktak.com\/vi\/thermal-grease\/low-thermal-resistance-grease\/\">m\u1ee1 t\u1ea3n nhi\u1ec7t c\u00f3 \u0111i\u1ec7n tr\u1edf nhi\u1ec7t th\u1ea5p<\/a> against the real bond line and production method.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Need to compare candidates in your own module stack? <\/strong><strong><a href=\"https:\/\/haktak.com\/vi\/contact\/\">Request samples or a material recommendation<\/a><\/strong><strong> with the module drawing, cooler details and operating profile.<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">C\u00e1c c\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">What thermal grease is best for an IGBT power module?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The best grease is the one that meets the module temperature target at a thin, repeatable bond line and remains stable after the required cycling. Compare interface thermal impedance, printability, pump-out resistance, temperature stability and compatibility. Follow the IGBT manufacturer&#8217;s mounting instructions before selecting thickness or application pattern.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How thick should thermal grease be under a power module?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">There is no universal thickness. Manufacturer examples often fall in the tens to low hundreds of micrometres, but each value belongs to a particular module and cooler condition. Use the module mounting guide, control deposited mass and verify the mounted transfer pattern and thermal result.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is higher thermal conductivity always better for power module grease?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">No. Higher W\/mK can help, but a thicker layer or poor wetting can cancel the benefit. Thermal impedance at the real bond line and pressure is usually more useful. Long-term stability and production repeatability also matter.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Should thermal grease cover the entire module baseplate?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The finished interface should provide effective coverage across the intended heat-transfer area without harmful voids. That does not always mean printing a solid rectangle. Module-specific stencil patterns may use separate deposits that spread during mounting. Follow the approved pattern for the module.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is stencil printing better than a roller or spatula?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Stencil printing is generally more repeatable for production because it controls volume and location. A roller or spatula may be accepted for prototypes, repairs or low-volume builds if the module maker permits it and the result is inspected. The method must produce the specified mounted interface.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Can thermal grease pump out during thermal cycling?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Yes. Repeated expansion and contraction can move grease away from active areas, especially when the compound, pressure and surface movement are poorly matched. Use thermal or power cycling, inspect coverage afterward and repeat the thermal measurement.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is power module thermal grease electrically insulating?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Some products are electrically non-conductive, but this should never be assumed from appearance or from the word \u201cgrease.\u201d Check the datasheet and safety architecture. A thin compound layer may not satisfy required dielectric, creepage or clearance protection.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">When should I use phase-change material instead of thermal grease?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Consider phase-change material when you want clean placement, controlled quantity and reduced handling variation in a thin clamped joint. Confirm activation temperature, wetting, pressure and reliability. Grease may remain preferable where room-temperature wetting and easy rework are important.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How do I calculate the amount of thermal grease for a module?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Estimate mass from effective coated area, average deposited thickness and material density. Then refine it with the actual stencil pattern and mounted transfer test. In production, weighing parts before and after application is a practical way to monitor deposited quantity.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">How should thermal grease be tested before mass production?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Start with material and compliance review, then compare candidates at relevant thickness and pressure. Run a process capability study, measure thermal performance in the real module-to-cooler assembly, apply the required environmental cycling, and finally inspect coverage and re-measure thermal resistance.<\/p>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Thermal grease for power modules fills the microscopic spaces between a module baseplate and a heat sink or liquid-cooled cold [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":1341,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1853","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-haktak-blog"],"_links":{"self":[{"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/posts\/1853","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/comments?post=1853"}],"version-history":[{"count":1,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/posts\/1853\/revisions"}],"predecessor-version":[{"id":1854,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/posts\/1853\/revisions\/1854"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/media\/1341"}],"wp:attachment":[{"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/media?parent=1853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/categories?post=1853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/haktak.com\/vi\/wp-json\/wp\/v2\/tags?post=1853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}