什麼是晶圓級封裝?

晶圓級封裝(Wafer Level Packaging)簡介晶圓級封裝(WLP，Wafer Level Package) 的一般定義為直接在晶圓上進行大多數或是全部的封裝測試程序，之後再進行切割(singulation)製成單顆組件。而重新分配(redistribution)與凸塊(bumping)技術為其I/O繞線的一般選擇。WLP封裝具有較小封裝尺寸(CSP)與較佳電性表現的優勢，目前多用於消費性IC的封裝應用(輕薄短小)。
    
常見的WLP封裝繞線方式如下：1. Redistribution (Thin film), 2. Encapsulated Glass substrate, 3. Gold stud/Copper post, 4. Flex Tape等。此外，傳統的WLP封裝多採用Fan-in 型態，但是伴隨IC信號輸出pin數目增加，對ball pitch的要求趨於嚴格，加上部分組件對於封裝後尺寸以及信號輸出腳位位置的調整需求，因此變化衍生出Fan-out 與Fan-in + Fan-out 等各式新型WLP封裝型態，其製程概念甚至跳脫傳統WLP封裝。

Wafer Level Packaging

在傳統晶圓封裝中，是將成品晶圓切割成單个晶片，然後再進行黏合封裝。晶圓級封裝(WLP)，顧名思義，就是在晶片還在晶圓上的時候就對晶片進行封裝: 保護層可以黏接在晶圓的頂部或底部，然後連接電路，再將晶圓切成單個晶片。

    
In conventional packaging, the finished wafer is cut up, or diced, into individual chips, which are then bonded and encapsulated. Wafer-level packaging (WLP), as its name implies, involves packaging the die while it is still on the wafer: protective layers may be bonded to the top and/or bottom of the wafer, then electrical connections are prepared and the wafer is diced into individual chips.

To provide a baking analogy, traditional packaging is similar to frosting individual cupcakes, while WLP is like frosting a whole cake and then slicing it into pieces. Because the sides are not coated with WLP, the resulting packaged chip is small in size (roughly the same size as the chip itself), an important consideration in footprint-sensitive devices such as our smartphones. Other advantages include streamlined manufacturing and the ability to test chip functionality before dicing.

參考資料: Semi Taiwan, semiengineering