利用雙重自我組裝技術於微電機及生醫系統應用之非平整表面晶片三維異質整合研究

Abstract

在三維異質整合中，分成晶片級製程及晶圓級製程，其中，晶片級製程雖然能達到較高的良率，但在產率方面仍有許多的問題，需要藉由新技術的開發來改善。尤其在微電機及生醫系統的三維異質整合上，由於此類晶片的體積較小且有表面非平整的因素，使得在整合上面臨了一些困難，包含操作時晶片的放置與固定，以及接合時的對準問題，皆與整合後的產率大小息息相關。 自我組裝技術在晶片級的三維異質整合具有相當大的潛力，此技術是利用疏水膜來定義親水晶片的堆疊位置，再藉由水表面張力的作用，能迅速完成小晶片的放置與對準程序，除此之外，也發現到利用水的毛細現象所產生的吸附力，能將表面不平整的晶片固定住。因此，在此篇論文中提出了「雙重自我組裝技術」。藉由雙重自我組裝技術以達成元件整合，同時解決了體積小的表面非平整晶片在操作放置上以及接合前對準的精準度問題。在本研究中，我們利用製作微米級柱狀陣列來模擬上述的非平整表面微系統晶片，探討對於微柱陣列的自我組裝所需的最佳水量，藉由水的毛細作用所產生的吸附力，達到最佳的自我組裝能力，使得此非平整表面晶片能暫時吸附在承載晶圓上，以利於後續晶片的整合；此外，本研究也探討了不同晶片大小在自我組裝時，藉由水表面張力的作用，能達到最高對準精準度所需的最佳水量，以解決晶片堆疊時的對準問題。 在本篇論文中，我們提供了雙重自我組裝的技術製程以及接合後的電性量測，並且藉由可靠度分析來檢測接合品質，從良好的接合結果，可證明此雙重自我組裝技術可以成功運用在非平整表面晶片的整合，因此也能有效應用在微電機以及生醫系統的三維異質整合。

Although chip-level heterogeneous integration provides high yield, its low throughput issue is necessary to be addressed. With regard to the integration of microelectromechanical systems (MEMS) and biomedical microsystem, handling issue and alignment accuracy are the factors that impact the difficulty in integration due to the uneven topography and small chip size. These problems are related to throughput of both chip stacking and the following bonding process. Self-assembly technology has a high potential in 3D heterogeneous integration. Through hydrophobic film to define the desired stacking areas, hydrophilic chips can be assembled on these areas by the surface tension of water in a short time and accomplish alignment process. In this thesis, double-self-assembly technology is introduced to settle both handling and alignment issues for uneven topography chip microsystem integration, such as biomedical and MEMS applications. In this research, the μ-pillar chips are demonstrated to simulate the microsystem to investigate the optimal water volume for self-assembly process under various pillar heights to achieve high self-assembly ability. By achieving this ability, temporary bonding on carrier wafers can also be realized. Furthermore, the optimal water volume for different chip size is researched. Under misalignment measurement, high alignment accuracy can be accomplished with the optimal water volume for self-assembly process. In this thesis, the microstructure of bonded structures and corresponding electrical analysis are proposed. Moreover, various reliability tests are undertaken to examine the bonding quality. Excellent bonding results prove that this double-self-assembly technology is applicable to 3D heterogeneous integration for uneven-topography biomedical MEMS chip integration.