CMOS電容式微麥克風之設計與製作

Design and Implementation of a CMOS Capacitive Micromachined Microphone

廖時新(Shih-Hsin Liao)

指導教授 ： 盧向成

國立清華大學/電機資訊學院/電子工程研究所/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00579

摘要

本研究設計與製作出一個CMOS-MEMS電容式麥克風。此麥克風使用新穎的微結構設計，在低面積下具有高靈敏度。後製程簡單且可於低溫下完成。不需作額外的薄膜沉積，且容易與CMOS標準製程整合於單一晶片上。

於製程上使用TSMC 0.35-um 2P4M CMOS標準製程定義電路與微結構。在後製程進行濕蝕刻以釋放微結構，與等向性蝕刻passivation層打開I/O pads，即可完成此麥克風。

本晶片包含五組不同設計的麥克風，總晶片面積為2.46x2.46 mm2。單一組麥克風的工作電壓為3.3 V，電流消耗為1.04 mA，微結構面積為190x190 um2，總面積為0.95x0.8 mm2 (包含I/O pads)。在聲壓為1 Pa且頻率為1 kHz的量測環境下，此麥克風的靈敏度為-37.21 dBV/Pa，訊雜比為57 dB，等效輸入雜訊為3.16 uV/√Hz，關聯性(coherence)為0.98，感測頻寬為2.32 kHz。

關鍵字

CMOS ； MEMS ； 電容式 ； 凝縮式 ； 麥克風

並列摘要

This work describes the design and implementation of a CMOS-MEMS capacitive microphone. The microphone with a novel micro-structure design has a high sensitivity in a small area. The post-process is simple and can be completed at low temperatures. Without additional thin film deposition, it is easy to be integrated with the CMOS process on a single chip.

The sensor is fabricated by using TSMC 0.35-um 2P4M CMOS process. After metal wet etching to release the micro-structure, a dry etching is performed to remove passivation layers to open the I/O pads.

This chip contains five different sets of microphones, and the total chip size is 2.46x2.46 mm2. The power supply of each set is 3.3 V; the current consumption is 1.04 mA; the area of micro-structure is 190x190 um2; and the area of each set is 0.95x0.8 mm2 (including I/O pads). The sensitivity is -37.21 dBV/Pa measured at 1 Pa and 1 kHz; the signal-to-noise ratio is 57dB; the equivalent input noise is 3.16 uV/√Hz; the coherence is 0.98; and the sensor bandwidth is 2.32 kHz.

並列關鍵字

CMOS ； MEMS ； capacitive ； condenser ； microphone

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