利用奈米碳管叢加熱製作球閘陣列封裝錫球之研究

Fabrication of BGA solder balls by heating on CNT forests

鄭煒儒(Wei-Ru Cheng)

指導教授 ： 張所鋐

國立臺灣大學/工學院/機械工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.01333

摘要

隨著電子工業技術不斷的演進，電子產品輕型化的需求日增，這其中的關鍵之一便是電子構裝技術的進步，為了達到使電路小型化與I/O腳數增加的雙重需求，表面貼裝科技 (Surface Mount Technology, SMT)取代了傳統的導線架封裝方式，而其中球閘陣列封裝即為進入實用化階段的高密度構裝技術。錫球在球閘陣列封裝中扮演一關鍵的角色，錫球的製造方法有採用粉末冶金技術的霧化法，以及切絲重熔法，到近年來發展出來高效率的均勻液滴成型法，這些製程方法均有其優缺點：霧化法的製程方法簡單，容易大量生產，但不易控制製程參數，導致錫球成品須進一步的嚴密篩選和檢測；切絲重熔法其設備簡單、成本較低，對於成品的可控性也較佳，但相較之下工序多而生產效率低，精確度也不佳；均勻液滴成型法其可控性、精確度、生產效率皆較佳，但生產設備複雜且成本高。
因此本研究提出一種新的錫球製作方法，主要是改變切絲重熔法，利用奈米碳管叢作為成型設備，錫塊材料在奈米碳管叢上因為表面的蓮葉效應，使得熔融態的錫會因為內聚力的作用而自行聚成球狀，球化過程極快(2~3秒)，且此製程在錫球的重熔過程中溫度可比油浴加熱高許多，可適用於較高熔點的焊錫材料。本研究探討此錫球製程的實用性，針對在不同溫度下、氫氣通量下以及不同奈米碳管叢高度和層數等各種參數下製作之錫球進行檢測、統計。

關鍵字

BGA錫球 ； 奈米碳管 ； 奈米碳管叢加熱器

並列摘要

As the evolution of electronic industry technology, the demand for thinner electronic products increased over time, and the progress of electronic packaging technology becomes crucial. To meet the requirement of both smaller electronic circuit and more I/O pins, surface mount technology (SMT) replace the old leadframe packaging. Ball grid array (BGA), a high density packaging method, is one of which entered the practical stage. The crucial roles of BGA are the solder balls it used. There are mainly three methods of solder ball fabrication: atomization adapted from powder metallurgy, cutting-remelting, and recently developed uniform-droplet spray (UDS). Those methods have advantages and disadvantages. The process of atomization is simple and easy to mass production, but it is difficult to control the process parameters. The solder balls made by atomization have to be strictly filtered and examined. Cutting-remelting is more controllable and lower cost of the production equipment, but the precision of the solder balls is not good, and production efficiency is low due to the excessive processes. UDS is well controllable, high precision, and high efficiency, but the production equipment is relatively complicated and high cost.
A new fabrication method of solder balls is presented in this work. The method is mainly using carbon nanotube (CNT) forests as the solder ball forming device. The shape of solder masses on the carbon nanotube forests turn into spherical in liquid state owing to the lotus effect between the liquid solder and the top surface of the CNT forests. The spheroidization of solder alloy is fast (2~3 sec.). And because of the high melting point of CNT, the temperature of remelting process in solder ball fabrication can reach higher than in oil bath (~300°C), which is suitable to solder alloys with higher melting point. The practicality of this solder ball fabrication method is studied in this work. Solder balls were fabricated with different process parameters such as: remelting temperature, hydrogen flux through, height and layers of CNT forests were examined, and statistical results were made.

並列關鍵字

BGA solder ball ； Carbon Nanotube ； CNT forests heater

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