銦與鎳基材之介面反應及其介金屬機械性質量測

Interfacial Reaction of Liquid In with Solid Ni and the Mechanical Properties of Ni-In Intermetallic Compound

廖家儀(Chia-Yi Liao)

指導教授 ： 高振宏

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202102563

摘要

由於現今電子封裝產業將電子元件縮小化的趨勢，微影製程已逐漸逼近其物理極限。然而三維積體電路藉由微銲點與矽穿孔技術，可輕易達成晶片的垂直堆疊與垂直整合，因此被普遍視為延續莫爾定律甚至是開啟後莫爾時代的的最佳解法。縱然三維積體電路有著如此多吸引人的優點，一些相關的隱憂也隨電晶體尺寸的縮小而浮上表面。比如用於三維積體電路微銲點，其銲料會快速的與底材反應而形成介金屬，進而占據整個接點。屆時，此接點的機械性質將不再由銲料本身所主導，相反的，則是由介金屬控制。另外，對於一些更高層級且熱敏感的元件，比如生物型晶片或是光電元件等，在接合過程中有因高溫而失效的風險在。為了解決高溫接合對熱敏感元件所帶來的負面影響，新的低溫接合技術以及低溫無鉛銲料已經成為一個備受關注的議題。而熔點僅有156 ℃的銦，則恰好可以解決這個難題。而除了低熔點，使用銦做為銲料還有其他優點，比如高的導電性以及導熱性，良好的延展性以及自我對位的能力等。上述所說的特質都足以讓銦成為有潛力的低溫銲料。然而，在以往的研究中使用銦做為銲料的實在是少數，相對地使用錫或是錫合金做為銲料的研究反而不勝其數。其原因可歸咎於銦的質地過於柔軟，使其金相觀察不易所造成的。
因此在我的研究中，我選擇銦作為低溫焊料與常見的鎳基板進行反應。鎳銦在200 ℃，225 ℃以及250 ℃下的固液反應將是此實驗的重點所在。另外，基於上述所討論到的，微銲點中的銲料與底材反應而形成的介金屬有機會佔據整個微銲點，因此介金屬在微銲點可靠度中扮演一個重要角色。在此鎳銦二元系統中的介金屬將會用奈米壓痕機來測量機械性質。

關鍵字

三維積體電路 ； 低溫焊料 ； 奈米壓痕機 ； 銦 ； 鎳

並列摘要

Due to the physical limitation of lithography process, industries are now faced with a dilemma of scaling down electronic component size. By using Through-Silicon-Via and Micro-Joints to achieve vertical stack of chips, three-dimensional integrated circuits (3D ICs) is therefore regarded as the savior that is able to extent Moore’s law or even create the era of More-than-Moore. In spite of such a promising prospect for 3D ICs, many issues also arise accompanying with the miniaturization of transistor in micro-bump. For example, solder in a micro joint will react quickly with substrate and then transform totally into intermetallic compound, and the mechanical properties of this joint are thus no longer dominated by solder itself but for IMC. Also, for some sensitive devices like bio-chip or optoelectronic devices will encounter the risk of bond failure due to heat localization at such small volume of electronic components. In order to prevent the failure caused by high temperature bonding process, the development of lead-free low-temperature solder material is of great importance. Indium, whose melting point is only about 156 ℃, can be used to overcome this difficulty. It's also worth mentioning that, indium processes not only low melting point but also high thermal and electrical conductivity, excellent ductility and self-alignment capability. All of these benefits mentioned above make it become one of the most competitive low-temperature solders nowadays. However, studies taking indium as solder material are much less than that of using Sn or Sn-Ag-Cu solder due to its nature softness.
As a result, I choose indium as a low-temperature solder material in my study while commonly-used Ni as substrate material. In this research, the interfacial reaction between solid nickel and liquid indium at 200 ℃, 225 ℃ and 250 ℃ are studied. Since the reliability of micro joints are predominated by intermetallic compounds unlike conventional flip-chip joints or ball grid array (BGA) joints, the mechanical properties of IMC in this Ni-In binary system are also explored by using nanoindenter.

並列關鍵字

nanoindenter ； nickel ； indium ； low-temperature solder ； 3D IC

參考文獻

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2.Bahareh Banijamali., et al., Outstanding and Innovative Reliability Study of 3D TSV Interposer and Fine Pitch Solder Micro-bumps, 2012

3.T.H. Chuang., et al Interfacial Reactions between Liquid Indium and Nickel Substrate, 1999

4.Tanawan Chaowasakoo., et al., Indium Solder as a Thermal Interface Material Using Fluxless Bonding Technology, 2009

5.Tu, K.N., Reliability challenges in 3D IC packaging technology. Microelectronics Reliability, 2011. 51(3): p. 517-523.