本文研究方向為研究Au/Si/TMAH的Galvanic電化學蝕刻停止，並找出在製作微結構時所需具備的設計條件。

Galvanic電化學蝕刻停止是利用Au/Si/TMAH的結構，使得在擁有PN接面的晶片在TMAH中蝕刻時，P型矽會被蝕刻而N型矽則會被保留下來，此一方法改善了一般蝕刻停止，所需要的高濃度硼離子摻雜產生的應力問題，以及電化學蝕刻停止需要的外加偏壓及夾具保護，所產生的不能批次製造及熱應力問題。

所選擇的蝕刻溶液為TMAH，其相容於COMS製程，且加入特定的添加物可以使得對鋁材的選擇性提高，甚至不會蝕刻，使得本論文的應用更加有彈性。

最後，利用所找出的設計條件製作一懸臂樑結構以驗證參數的可行性。

The main purpose of this thesis is to study on Galvanic electrochemical etch stop using Au/Si/TMAH formation and tries to find out the conditions that we make micro-structure should need.
Through the formation of Au/Si/TMAH, the wafer which have PN junction etch in TMAH, P type Si would be etched and N type Si would be protected. This mechanism improves the following problem：(1) the stress problem that due to the heavily boron-doped etch stop; (2) the non-batch fabrication and thermal stress problem that electrochemical etch stop have to use external bias and holder protection.
We use TMAH as an etchant. Its advantages are：(1) compatible with the COMS process, (2)adding the specific additive that can increase the selectivity of aluminum, even non-etch. The application of this research will be more elasticity.
Finally, for testing and verifying the feasibility of the parameters, author applied the designing conditions to fabricate the beam structure.

目錄 .................................................... i
表目錄 ................................................ iii
圖目錄 ................................................. iv
中文摘要 ............................................. viii
英文摘要 ............................................... ix
第一章 緒論 ............................................ 1
1.1 微機電系統簡介 .................................. 1
1.2 研究動機 ........................................ 4
1.3 本文目的及論文架構 .............................. 8
第二章 Galvanic電化學蝕刻停止理論 ..................... 10
2.1 單晶矽蝕刻機制 ................................. 10
2.2 非等向性濕式蝕刻機制 ........................... 11
2.3 電化學蝕刻機制 ................................. 15
2.3.1 P型矽的電化學蝕刻 ......................... 16
2.3.2 N型矽的電化學蝕刻 ......................... 17
2.4 電化學蝕刻停止 ................................. 18
2.5 Galvanic電化學蝕刻停止 ........................ 20
2.5.1 無電極蝕刻機制 ........................... 20
2.5.2 Galvanic電池的構成與鈍化 ................. 21
第三章 實驗設計 ....................................... 25
3.1 TMAH蝕刻特性 ................................... 25
3.2 影響鈍化之因素 ................................. 27
3.3 實驗流程 ....................................... 28
第四章 實驗結果與討論 ................................. 31
4.1 實驗結果 ....................................... 31
4.2 Galvanic電化學蝕刻停止之應用 ................... 33
第五章 結論與未來展望 ................................. 36
參考文獻 ............................................... 39
附表 ................................................... 42
附圖 ................................................... 49






表 目 錄

表2-1 常用金屬的標準電位序 ............................ 42
表2-2 N型矽與P型矽之鈍化電位之OCP ..................... 42
表3-1 TMAH與KOH蝕刻速率之比較 ........................ 43
表3-2 TMAH對不同材料的蝕刻選擇性 ..................... 43
表3-3 面積效應試片設計數據 ............................ 44
表3-4 距離效應試片設計數據 ............................ 45
表4-1(a) N型矽面積效應之實驗結果 ...................... 46
表4-1(b) P型矽面積效應之實驗結果 ...................... 47
表4-2 距離效應之實驗結果 .............................. 48
表4-3 無Galvanic電化學蝕刻停止之試片在各溫度之蝕刻速率.48







圖 目 錄

圖1-1 微機電系統之三大方向 ............................ 49
圖1-2 高濃度硼離子摻雜之應用 .......................... 50
圖1-3 電化學蝕刻停止之應用 ............................ 49
圖1-4 光電壓電化學蝕刻之應用 .......................... 51
圖1-5 Galvanic電化學蝕刻停止之應用 .................... 51
圖2-1 Miller indices各晶面之示意圖 .................... 52
圖2-2 蝕刻溶液與矽之能帶圖 ............................ 52
圖2-3 三電極電化學蝕刻系統 ............................ 53
圖2-4 四電極電化學蝕刻系統 ............................ 53
圖2-5 在80℃ 25wt% TMAH中P型矽的電流電位曲線圖 ........ 54
圖2-6(A) TMAH中P型矽陽極鈍化電流與溫度及濃度之關係圖 . 54
圖2-6(B) TMAH中N型矽陽極鈍化電流與溫度及濃度之關係圖 . 55
圖2-7 P型與N型電流電位曲線圖 ......................... 55
圖2-8 N型與P型矽電流電位曲線與其蝕刻行為 ............. 56
圖2-9 Bipolar電化學蝕刻模型 ........................... 56
圖2-10 P型矽在不同濃度氧化劑之電流電位曲線圖 .......... 57

圖2-11 三電極電化學系統與Galvanic電池結構在鹼性溶液之示意
圖.............................................. 57
圖3-1 (100)矽濃度對其蝕刻速率關係圖 ................... 58
圖3-2 TMAH之濃度、溫度對N、P型矽之蝕刻速率關係圖 ....... 58
圖3-3 Galvanic effect的距離效應 ....................... 59
圖3-4 試片之示意圖 .................................... 59
圖3-5(a) 試片製程-準備N型與P型晶片並長上氧化層 ....... 60
圖3-5(b) 試片製程-以光罩(一)定義接觸窗 ................ 60
圖3-5(c) 試片製程-以BOE蝕刻接觸窗之氧化層 ............. 60
圖3-5(d) 試片製程-濺鍍Cr與Au .......................... 60
圖3-5(e) 試片製程-以光罩(二)定義陰極面積 .............. 61
圖3-5(f) 試片製程-蝕刻Cr及Au並以光罩(三)定義暴露窗 ... 61
圖3-5(g) 試片製程-以BOE蝕刻暴露窗之氧化層 ............. 61
圖3-5(h) 試片製程-側邊以黑蠟密封 ...................... 61
圖4-1(a) 蝕刻停止--試片置於90℃ 25wt% TMAH 1小時 ....... 62
圖4-1(b) 蝕刻停止--試片置於85℃ 25wt% TMAH 30 分鐘 ..... 62
圖4-1(c) 蝕刻停止--試片置於75℃ 25wt% TMAH 30 分鐘 ..... 63
圖4-1(d) 蝕刻停止--試片置於70℃ 25wt% TMAH 30 分鐘 ..... 63
圖4-1(e) 無蝕刻停止--試片置於90℃ 25wt% TMAH 30 分鐘 ... 64
圖4-1(f) 無蝕刻停止--試片置於85℃ 25wt% TMAH 30 分鐘 ... 64
圖4-1(g) 無蝕刻停止--試片置於80℃ 25wt% TMAH 30 分鐘 ... 65
圖4-2 無側邊保護之試片置於90℃ 25wt% TMAH 1小時 ........ 65
圖4-3 使用氧化層保護側邊 .............................. 66
圖4-4(a) 日東電工鐵氟龍膠帶973UL ...................... 66
圖4-4(b) 利用鐵氟龍膠帶密封側邊 ....................... 67
圖4-5 使用黑蠟保護側邊 ................................ 67
圖4-6 P型矽上Au被掀起 ................................ 68
圖4-7 P型矽上Au鼓起 .................................. 68
圖4-8 試片中Au掀起的情況 .............................. 69
圖4-9 Au被蝕刻，底下Cr附著層的情形 .................... 69
圖4-10 Cr被蝕刻，底下矽的情形 .......................... 70
圖4-11 距離效應--N型試片置於90℃ 25wt% TMAH中30分鐘 .. 70
圖4-12 有側邊保護的N型矽置於70℃ 27%的KOH 30分鐘 ..... 71
圖4-13(a) 懸臂樑製作--準備有N磊晶的P型晶片 ........... 72
圖4-13(b) 懸臂樑製作--罩(一)定義暴露窗並蝕刻Nitride與
Oxide ....................................... 72
圖4-13(c) 懸臂樑製作-- 以KOH蝕刻暴露窗的N型磊晶矽 .... 72
圖4-13(d) 懸臂樑製作--以光罩(二)定義接觸窗並蝕刻Nitride與
Oxide ....................................... 72
圖4-13(e) 懸臂樑製作—濺鍍Cr與Au，再以光罩(三)定義陰極面
積並蝕刻之 .................................. 73
圖4-13(f) 懸臂樑製作--置入80℃ 25wt% TMAH中蝕刻 ....... 73
圖4-14 以光罩(一)定義暴露窗 ........................... 74
圖4-15 以RIE蝕刻氮化矽 ................................ 74
圖4-16 以BOE蝕刻二氧化矽 .............................. 74
圖4-17 以80℃ 27% KOH蝕刻至20μm ...................... 75
圖4-18 以光罩(二)定義及蝕刻接觸窗 ..................... 75
圖4-19 濺鍍Cr/Au及以光罩(三)定義陰極面積大小 .......... 75
圖4-20(a) 懸臂樑試片以25wt%的TMAH蝕刻2小時 ........... 76
圖4-20(b) 將懸臂樑挑斷露出底切部分 .................... 76

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