整合光輔助電化學穿孔蝕刻與微電鑄技術應用於微金屬柱陣列之研製
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Date
2007-11-23
Authors
楊啟榮
李明承
羅嘉佑
張龍吟
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Abstract
本研究將整合光輔助電化學蝕刻(ECE)與精密電鑄技術，以開發高密度金屬垂直結構陣列之製程技術。利用改變光照強度與電流密度等實驗條件，以電化學蝕刻達到矽晶圓高密度微穿孔的目的，再利用精密電鑄技術進行穿孔之金屬導體填充，如此可實現高密度金屬垂直結構陣列。未來可應用於積體化探針陣列之製作，或利用晶圓內垂直導體而實現晶圓級堆疊封裝之目的。此技術開發有設備與製程成本低、可積體化生產、與半導體製程相容性高、批次生產與良率高等特點。 基於上述，本研究利用自行開發之低成本電化學蝕刻(ECE)設備，順利測得相關製程之最佳參數。由實驗結果已驗證，在利用電化學蝕刻技術製作高深寬比微孔洞陣列方面，當蝕刻時間達到31.5小時，可得高深寬比之穿孔結構。所用之晶片為n-type <100>，其蝕刻液為2.5 wt.%之氫氟酸溶液，陽極放置矽晶片，陰極為白金電極，獲得之穿孔其線寬為40 μm，深寬比約為12.5，證明利用此技術已能局部取代乾式蝕刻之應用領域。在金屬柱電鑄方面，利用正負脈衝電流，使金屬柱陣列能順利成形，其金屬柱高度約500 μm，深寬比約為12.5。
This research will integrate photo-assisted electrochemical etching (ECE) and electroforming techniques for fabricating high-density metal micropillars. This process is described as followed: high-density through holes in silicon are etched by photo-assisted electrochemical etching under various parameters; then the through holes are fully filled by copper electroforming technique to form high-density metal micropillars. The deveploed technology will be promising for the application of integrated probe array and wafer-level package in the further. Because of the above-mentioned, this research used the low-cost electrochemical etching (ECE) equipment developed by ourselves and got the best parameters of the related manufacture. The experiment results proved that the technology had been able to partially replace the dry etching technology. Using the ECE technology to fabricate high aspect of micro-pores array, we can get the structures of high aspect when the etching time reached 31.5 hours. Through-holes were formed by selective partial electropolishing in a 2.5wt.% HF electrolytic solution, using an N-type, (100)-oriented Si wafer as an anode, and a Pt plate as a cathode. The obtained holes were square through-holes of 40.mu.m side length, with an aspect ratio of 12.5. Metal micropillars were made by electroforming technology with pulse and reverse current. The height of metal micropillars achieve 500.mu.m and the aspect ratio can reach 12.5.
This research will integrate photo-assisted electrochemical etching (ECE) and electroforming techniques for fabricating high-density metal micropillars. This process is described as followed: high-density through holes in silicon are etched by photo-assisted electrochemical etching under various parameters; then the through holes are fully filled by copper electroforming technique to form high-density metal micropillars. The deveploed technology will be promising for the application of integrated probe array and wafer-level package in the further. Because of the above-mentioned, this research used the low-cost electrochemical etching (ECE) equipment developed by ourselves and got the best parameters of the related manufacture. The experiment results proved that the technology had been able to partially replace the dry etching technology. Using the ECE technology to fabricate high aspect of micro-pores array, we can get the structures of high aspect when the etching time reached 31.5 hours. Through-holes were formed by selective partial electropolishing in a 2.5wt.% HF electrolytic solution, using an N-type, (100)-oriented Si wafer as an anode, and a Pt plate as a cathode. The obtained holes were square through-holes of 40.mu.m side length, with an aspect ratio of 12.5. Metal micropillars were made by electroforming technology with pulse and reverse current. The height of metal micropillars achieve 500.mu.m and the aspect ratio can reach 12.5.