利用金屬輔助化學蝕刻配合田口數值分析製造高深寬比之矽微米洞狀結構

高深寬比矽晶結構在半導體產業扮演著重要的角色。隨著時代的變遷與科技的進步，晶片的發展趨向微小化、多功能化。因此，對於製造微米、奈米尺寸高深寬比矽晶結構的技術與需求不斷提升。目前，市面上已被廣泛用來製造該結構的方法為深反應性離子蝕刻(Deep reactive-ion-etching，DRIE)。然而，此製造方法需要複雜的設備裝置及瑣碎的製程過程，因此，所需成本昂貴。因此，我們想利用相對製程簡單、成本低廉的蝕刻方法—金屬輔助化學蝕刻（Metal-assisted-chemical-etching，MACE）來製造相同的結構。金屬輔助化學蝕刻能夠在室溫環境下於矽晶片上朝<100>方向蝕刻，此蝕刻反應過程簡單，且只需用到一般的化學反應槽及簡單的化學溶液。本論文的研究目的就是想利用金屬輔助化學蝕刻透過田口分析與變異數分析的優化處理，得出蝕刻的最佳條件；然後，透過濕式爐管氧化與高濃度氫氟酸處理，將MACE後殘留的矽線移除乾淨。最終，希望得到能與DRIE製程結果媲美的高深寬比矽微米孔洞結構。根據本研究結果顯示，深寬比約13，邊長為四微米的方形陣列矽晶結構已成功的被製造出來。同時，在優化條件下的MACE蝕刻速率每秒可達三微米。然後，本研究結果也呈現了一個新穎並具備高生產效能的方法來製造高深寬比矽晶微結構。除此之外，我們也相信本方法能夠被進一步改良而得到更高深寬比、結構更平滑的結果，如：增加氮化矽（SiNx）保護層的厚度、用更強的保護層取而代之、發掘能夠更好控制金屬催化劑分佈的方法與機制。

關鍵字

高深寬比；矽穿孔結構；金屬輔助化學蝕刻；田口方法

並列摘要

High aspect ratio (AR) Silicon base structure plays an important role in semiconductor industry. Recent advances in small size and multifunctional chip has made the increased demands of fabrication of micro and nano scale high AR silicon structure. However, the commercial fabricating method, deep reactive ion etching (DRIE) suffers from high cost and complex processing due to the high maintenance fees and complicated set up. In contrast, we investigate the ability of promising novel chemical etching, metal assisted chemical etching (MACE) that can etch Silicon (Si) wafer in <100> direction near room temperature and thus benefits from it’s simple and cost effective reaction process. In order to fabricate high AR silicon micro holes structure, we have optimized our MACE recipe by employing statistical Taguchi L9 method and ANOVA analysis. Subsequently, the post-MACE formed Si wires have been removed by furnace oxidation followed by Hydrofluoric acid (HF) treatment. Therefore, high AR Si micro holes structure with smooth surface is obtained. Our results demonstrate that the AR value is up to 13 (for 4x4um square arrays in p-type (100) Si substrate), and the etching rate of optimal condition is about 3 µm/min. Moreover, an alternative method that possess larger throughput for fabricating high AR Si micro structure has been performed. Besides, it is believed that the AR value can be further improved by increasing the thickness of Si nitride layer (protection layer), using stronger protection layer instead, and exploring the method that can well-control the morphology of metal catalyst which strongly influence the post-etched structure.

並列關鍵字

high aspect ratio ； through silicon via ； metal-assisted chemical etching ； Taguchi method

參考文獻

2. Liu, R.Y., et al., Lithography-free fabrication of silicon nanowire and nanohole arrays by metal-assisted chemical etching. Nanoscale Research Letters, 2013. 8: p. 1-8.

3. Vasilache, D., et al., Through wafer via holes manufacturing by variable isotropy Deep RIE process for RF applications. Microsystem Technologies-Micro-and Nanosystems-Information Storage and Processing Systems, 2012. 18(7-8): p. 1057-1063.

4. Zahedinejad, M., et al., Deep and vertical silicon bulk micromachining using metal assisted chemical etching. Journal of Micromechanics and Microengineering, 2013. 23(5).

5. Wang, D., et al., Ordered arrays of nanoporous silicon nanopillars and silicon nanopillars with nanoporous shells. Nanoscale Research Letters, 2013. 8: p. 1-9.

6. Peng, K.Q., et al., Dendrite-assisted growth of silicon nanowires in electroless metal deposition. Advanced Functional Materials, 2003. 13(2): p. 127-132.

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利用金屬輔助化學蝕刻配合田口數值分析製造高深寬比之矽微米洞狀結構

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