銅散熱元件之MIM製程及散熱性質研究

陳柏源(Bor-Yuan Chen)

指導教授 ： 黃坤祥

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00139

摘要

隨著高科技的日新月異，電子產品的發展趨勢均朝向高能量密度及小體積發展，熱管理問題勢必將是未來電子產業的一大挑戰，因此冷卻技術的研發將被視為重要的發展目標。散熱片(Heatsink)具有高散熱表面積、幾何形狀多樣化及製程技術成熟等特性，而熱導管則具有熱響應迅速、低熱阻、重量輕及無噪音等特性，因此本研究將結合散熱片與熱導管兩者優越之特性，以金屬粉末射出成形製程(Metal Injection Molding，簡稱MIM)製作平板式熱導管(Vapor Chamber)之銅散熱元件。

本研究可分為三部份，第一部分著重於散熱鰭片之薄件射出，提高鰭片之高寬比、降低厚度、增加鰭片數量及散熱片底座設計城牆形狀，並探討射出、溶脫、熱脫及燒結參數對超薄型散熱銅鰭片之射出成形製程的影響。此外，針對回收料進行分析，以便對射料的回收再利用可行性作初步判斷。本研究在不施加保壓的射出條件下，已可順利射出具有32片鰭片之超薄型散熱銅鰭片，且鰭片之高寬比分別為8.8、11.7、16.0及17.6，而鰭片與底部燒結後之密度均可高達96%，即表示無連通孔產生之顧慮，對於將熱迅速傳至鰭片之能力也較不受影響。在散熱性能方面，散熱片之熱阻值大約為1.156℃/W，而在Tj溫度為70℃及Ta溫度為24℃時，所能負荷的功率大約為40W。
第二部份則是評估平板式熱導管(Vapor Chamber)之毛細結構和注水量對散熱性能的影響。研究發現毛細結構以Powder-Mesh優於Mesh-Mesh，而工作流體為孔隙率的100%注水量時，可達到最低熱阻值1.046℃/W，且在Tj溫度為70℃及Ta溫度為26℃時，所能負荷的功率已經提高到42W。

最後將討論製程參數對射出工件性能之影響，此包括了乾壓製程與MIM製程對試片導電率的影響、添加硬脂酸鋰對燒結密度之影響、添加金屬元素鉍(Bismuth)和浸泡有機溶液對銅試片抗氧化能力之影響、冷均壓加工對試片燒結密度之影響、添加少量金屬元素對硬度之影響以及探討不同比例的PE含量對銅粉射出成形之影響。實驗結果顯示在高射速情況下，隨著PE含量的增加則具有較好的填模流動性質，在冷均壓加工方面，試片燒結密度可提升至97.4%左右。物理性質方面，在相同燒結密度下，MIM製程的試片導電率為74 % IACS明顯低於傳統粉末冶金製程的試片，其導電率大約為87 % IACS，而利用散佈強化或固溶強化機制，分別添加W、Mo、Ag及Fe3P等元素，皆可有效提高銅之硬度。

關鍵字：金屬粉末射出成形、銅粉、散熱片、平板式熱導管

關鍵字

金屬粉末射出成形 ； 銅粉 ； 散熱片 ； 平板式熱導管

並列摘要

The trend of the processor performance is higher power and thus heat dissipation increases significantly every year. As heat dissipation increases, the current trend of the electronic packages is to make smaller, lighter, and thinner devices. The thermal management has become more and more challenging as new electronic devices become more compact but without sacrificing their performances. Fortunately, the heatsink provided high surface area, geometrical pattern and maturity technology, and the heat pipe provide excellent heat transfer capability in cooling technology. In this research, the heatsink and heat pipe were combined to form the vapor chamber using the metal injection molding (MIM) process, and its heat dissipate performance was evaluated.

The results of this study were divided into three sections. The first part was to find processing parameters that can increase the number and the aspect ratio of fins. The result of the first part show that the holding pressure plays an important role. After sintering, the densities of the fin and the bottom plate are both about 96%. The thermal resistance is 1.156℃/W, and the power dissipation is 40W when the junction temperature is 70℃. In the second part, the efficiencies of wick and working fluid were evaluated. The optimum condition is Powder-Mesh wick with all pores filled with water. The thermal resistance is 1.046℃/W, and the power dissipation is 42W when the junction temperature is 70℃. Finally, the processing parameters to improve the property of MIM’s specimen were studied. The results show that cold isostatic pressing process (CIP) can improve the relative density by about 1%. Increasing PE content can reduce the injection resistance in the spiral flow test. The hardness could be increased by adding W, Mo, Ag and Fe3P respectively. On the electric conductivity, specimen of MIM process is inferior to the traditional powder metallurgy process.

Keywords：Metal Injection Molding(MIM), Copper Powders, Heatsink, Vapor Chamber, Heat Dissipation.

並列關鍵字

Metal Injection Molding(MIM) ； Copper Powders ； Heatsink ； Vapor Chamber ； Heat Dissipation

參考文獻

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