奈米碳材/陶瓷顆粒複合散熱材料應用於電子元件的開發與研究

Abstract

隨著AI伺服器、5G通訊和高功率晶片的發展，其運作時所產生的廢熱越來越多，散熱方面的熱管理(Thermal management)問題已成為重要的議題。電子元件是透過熱傳導、熱對流和熱輻射三種方式進行散熱，在元件追求輕薄短小的趨勢下，無風扇的散熱系統已經逐漸受到重視，在沒有風扇的主動散熱狀況下，依靠熱傳導的熱界面材料和熱輻射的散熱塗料就變得非常重要。本研究主要是以CO2超臨界剝離法製備石墨烯薄片(Graphene flakes, GNFs)，並利用大氣電漿改質技術對奈米碳材(GNFs、多壁奈米碳管(MWCNTs))和球型氮化鋁(AlN)、氧化鋁(Al2O3)顆粒等填充物進行改質，在填料表面嫁接上官能基，使填料與膠體基質之間結合的更緊密，進行熱界面材料(Thermal interface material, TIM)以及散熱塗料(Heat dissipation coating)的開發。 熱界面材料的研究是利用大氣電漿改質後的奈米碳材和球型AlN顆粒，混摻至市售導熱膏(Base-TIM)製備出複合奈米碳材熱界面材料(HA-TIM)以提升導熱性能。此HA-TIM以不同比例之AlN、GNFs以及MWCNTs作為填充物，期望以複合材料的方式在導熱膠材內部建立協同效應，進而使所製備的HA-TIM能有更好的熱傳導效果。最後，將熱界面材料應用於散熱設備上，以模擬CPU運作時的散熱狀況。實驗結果顯示以1 wt% GNFs以及1 wt% MWCNTs添加於Base-TIM中所製備出的HA-TIM具最佳的散熱性能。在50 W、100 W和150 W的加熱功率下，HA-TIM的降溫溫度比Base-TIM的降溫溫度分別更低了1.1 ℃、3.2 ℃和6.3 ℃，證實奈米碳材與球型AlN陶瓷顆粒的添加能夠提升降溫效果，使HA-TIM能夠實際應用於電子產品的散熱系統中。 奈米碳材散熱塗料的研究是以水性環氧樹脂作為高分子基質，製備出兼具低揮發性、環保且具高散熱性能需求的散熱塗料。此塗料是利用奈米碳材和Al2O3顆粒作為填充物，亦添加0.05 wt%磺基琥珀酸1,4-二己酯鈉鹽(SDSS)與1 wt%四丁基氯化銨(PDDA)兩種混合的界面活性劑作為石墨烯懸浮液的分散劑，以提升奈米碳材在水性環氧樹脂中的分散性，期望充份分散的填充物能發揮協同效應而產生優越的散熱性能。實驗結果顯示以30 wt% Al2O3、2 wt% GNFs以及2 wt% MWCNTs添加於水性環氧樹脂中所製備出的散熱塗料，其熱輻射係數可達到0.96。在10 W的加熱功率下，無添加界面活性劑的奈米碳材散熱塗料可使銅基板降溫11.9 ℃，而有界面活性劑的奈米碳材散熱塗料則可降溫17.8 ℃，證實添加界面活性劑的塗料，可提升5.9 ℃的散熱效果。實際應用於15 W LED的散熱測試，則可以達到21.3 ℃的散熱表現。證實本研究開發之奈米碳材散熱塗料，能有效地應用於電子元件的散熱領域。

With the development of artificial intelligence (AI) servers, 5G communications, and high-power chips, the waste heat generated during their operation is increasing, making thermal management an important issue. Electronic components dissipate heat through three methods: conduction, convection, and radiation. As components strive to be lighter, thinner, and more compact, fanless cooling systems are gaining attention. In the absence of active cooling from fans, relying on thermal interface materials for heat conduction and heat dissipation coatings for heat radiation becomes crucial. This study primarily uses CO2 supercritical exfoliation to prepare graphene flakes (GNFs) and employs atmospheric plasma modification technology to treat carbon nanomaterials (GNFs and multi-walled carbon nanotubes (MWCNTs)) and spherical aluminum nitride (AlN) and aluminum oxide (Al2O3) particles. Functional groups are grafted onto the surface of these fillers to enhance the bond between the fillers and the colloidal matrix, developing thermal interface materials (TIM) and heat dissipation coatings. The research on thermal interface materials involves mixing atmospheric plasma-modified carbon nanomaterials and spherical AlN particles into commercial thermal interface material (Base-TIM) to create composite carbon nanomaterials interface materials (HA-TIM) to improve thermal conductivity. HA-TIM uses different proportions of AlN, GNFs, and MWCNTs as fillers, aiming to create a synergistic effect within the thermal interface materials through the composite materials, thereby enhancing the thermal conductivity of the HA-TIM. Finally, the thermal interface materials are applied to cooling equipment to simulate CPU heat dissipation. The experimental results show that HA-TIM with 1 wt% GNFs and 1 wt% MWCNTs added to Base-TIM exhibits the best cooling performance. At heating powers of 50 W, 100 W, and 150 W, the temperature drops of HA-TIM are lower than those of Base-TIM by 1.1 ℃, 3.2 ℃, and 6.3 ℃, respectively, confirming that the addition of carbon nanomaterials and AlN ceramic particles can enhance cooling effects, making HA-TIM practically applicable in the heat dissipation systems of electronic devices. The research on heat dissipation coatings uses water-based epoxy as the polymer matrix to create coatings with low volatility, environmental friendliness, and high heat dissipation performance. These coatings use atmospheric plasma-modified carbon nanomaterials and spherical Al2O3 particles as fillers, along with 0.05 wt% sodium dihexyl sulfosuccinate (SDSS) and 1 wt% poly dimethyl diallylammonium chloride (PDDA) as mixed surfactants to improve the dispersion of graphene in the water-based epoxy, hoping that well-dispersed fillers can produce a synergistic effect and superior heat dissipation performance. Experimental results show that heat dissipation coatings with 30 wt% Al2O3, 2 wt% GNFs, and 2 wt% MWCNTs added to water-based epoxy achieve an emissivity of 0.96. The heat dissipation coating reduced the thermal equilibrium temperature of the bare copper panel by 17.8 °C under a heating power of 10 W. The coating was applied in a heat dissipation test on a 15 W LED bulb, and the thermal equilibrium temperature was reduced by 21.3 °C. This confirms that the heat dissipation coatings developed in this study can be effectively applied in the field of electronic component heat dissipation.