開發具垂直導線之撓性基板及其於三維異質整合應用

Development of Flexible Substrate with Through Hole Vias for 3D Heterogeneous Integration

許琇婷(Hsiu-Ting Hsu)

指導教授 ： 方維倫 ； 傅建中

國立清華大學/工學院/奈米工程與微系統研究所/碩士(2009年)

摘要

現今撓性基板的趨勢逐漸鮮明，撓性顯示器在市面上也顯露頭角，除此之外，感測器也陸續在發展中，由於機器人的發展演進，為了達到更接近人類以生俱來的感官功能，帶動了在機器人身上多處加裝撓性基板感測器的動機，其中包括溫度/溼度感測器、觸覺感測器、壓力感測器等發展。

另外在MEMS晶片封裝時所運用的垂直式導線不但有導線路徑最短的優勢，再藉由出平面方向與控制電路堆疊的整合，相對佔較少面積且符合現今電子產品輕、薄、短、小的需求，況且當MEMS元件是在一個高密度陣列的情況下，穿透晶片式導線將佔較最少面積，而使得元件設計面積能更有效被利用。

本研究將開發三維垂直導線於可撓性基板之平台，並進一步組裝不同功能性元件於此平台上，達到異質整合的目標。本文藉由發光二極體(LED)元件來驗證此三維垂直導線結合撓性基板平台的可行性。本研究利用聚對二甲苯(Parylene)高分子作為撓性基板材料，使用鎳金屬作為垂直導線，藉由兩種材料間的絕緣特性來作進一步的整合應用。由實驗結果得知，本研究成功的將水平與垂直電極LED元件整合於三維垂直導線結合撓性基板平台上。並且成功的將LED操作發光在曲率半徑2mm的彎曲平台上。另外，三維垂直Ni導線結合撓性基板的電性阻值為3.4Ω。LED與垂直導線之接合強度為158mg。藉由水中測試驗證撓性封裝的可行性。後續利用高分子PDMS高分子材料所製作的微透鏡進行整合。

關鍵字

撓性基板 ； 垂直導線 ； 聚對二甲苯

並列摘要

This study establishes the polymer-stacking and metal-electroplating processes on Si-substrate to implement a flexible and transparent substrate with alignment mesa, double-side electrical routing, and distributed 3D through-hole-vias. This process is especially useful for 3D integration of micro optical components on flexible substrate. The integrated chips can be further protected and sealed by an additional parylene coating. More micro-optical components can also be vertically integrated by additional polymer molding. To demonstrate the feasibility of this approach, LED chips are bonded and sealed in flexible substrate, and the polymer microlens is further integrated with the lighting chips using molding process. The lighting of packaged LED chips is demonstrated in both air and water.
In application, the study implemented the flexible-transparent substrate with 3D electrical-routings, and the assembly and integration of vertical/lateral LED chips and micro-lens was also demonstrated. The bonding strength was tested among LED-chip (Au)/Sn-paste/Ni-vias by using commercial bond-tester. The bonding strength of LED-chip and flexible substrate was 158 mg. The bulge test results show the adhesion force of Ni-vias and flexible-substrate is significantly improved by shape/area designs. Moreover, LED light-emission tests successfully demonstrate the feasibility of electrical-routings and through-hole vias of flexible substrate after bending. LED light-emission test in water further demonstrates the successfully sealing of devices. Finally, the study successful integrated packaged LED chips with PDMS-lens for light-emission testing.

參考文獻

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