微壓力感測器設計與製程模擬

SIMULATION OF THE DESIGN AND FABRICATION PROSESSES OF SILICON-BASE MICRO-PRESSURE SENSOR

許勝益(Sheng-I Hsu)

指導教授 ： 李碩仁

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

由於傳統的壓力感測器受到自身規格尺寸的影響，因此，對於使用的環境上有著相當大的限制。然而，近年來半導體製程技術快速發展，使得以半導體製程所製作的矽壓阻式壓力感測器不但有著比以往更加優良的感測靈敏度，更由於本身體積小的特點，使其能夠應用於各種場合。
本論文主要目的在於設計一量測0 ~ 250mmHg壓力範圍之微壓力感測器，由於矽薄膜變化特性以及壓電阻植佈方式乃是決定矽壓阻式壓力感測器感測靈敏與否的重要因素，因此，本論文乃就此要點作一探討。透過對於矽薄膜承受外力作用所產生的變形量給予適當的條件限制，進而決定最佳的感應薄膜厚度1.3μm，並根據應力模擬分析的結果，由於最大應力產生於矽薄膜的四邊中心點，因此，將壓電阻植佈於薄膜表面的最大應力分佈位置，且平行於[110]方向。根據設計所得到的電阻變化 ；且對於1.5V的定電壓源而言，其電壓輸出靈為8.49mV。
由於微小元件的製作過程容易產生設計誤差以及製程錯誤，導致良率降低，利用IntelliCAD製程模擬軟體，背部異向性蝕刻透過計算模擬的結果，可以在6.23小時達成要求；而壓電阻植佈可以利用內定製程離子植入法製作而得。不僅可以決定最佳的製程的步驟與順序，以提高良率；並且透過軟體的模擬特性呈現出每一製程步驟的元件外觀，以達到符合設計的要求。

關鍵字

矽壓阻式 ； 壓力感測器

並列摘要

Because the traditional pressure sensors are restricted by its size specification, they are subject to field space and environmental limitations. However, the rapid development of the semiconductor fabrication technology has greatly improved the sensitivity and linearity characteristics of the silicon-base piezzoresistor pressure sensors by the CMOS fabrication process. The advantages of the small size and competitive cost may replace some of the current products and may also open up new applications that we never thought of.
The main purpose of this research is to design a silicon-base micro-pressure sensor. The characteristics of measurement sensitivity is greatly affected by the deflection of silicon diaphragm and the doping of piezoresistor. In this thesis, a series of design simulation of FEA were conducted to obtain optimal diaphragm thickness of 1.3μm by given boundary conditions and 20% deformation restriction. Because the maximum stresses were located at the middle of square of silicon diaphragm, piezoresistors should be doped at these sites and in the direction of [110]. According to the design, the overall resistance variation is 0.57%. With 1.5V power supply, the maximum output voltage should be 8.49mV.
The fabrication processes have great influenced on the yield of micro-device. The IntelliCAD simulation results indicate that the anisotropic etching can be achieved in 6.23 hours, and the piezoresistors can be doped by ion implant. The IntelliCAD simulation system was employed to, first, analyze and verify each fabrication process, its optimal process parameters and the overall processing sequence. Secondly, the simulation results can also show the cell face step by step to verify the design specifications.

並列關鍵字

SILICON PIEZORESIST ； PRESSURE SENSOR

參考文獻

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