微機電熱阻式溫度感測器─封裝與感測器性能間之影響研究

A research on the effect of packaging on the performance of micro-thermal-resistor temperature sensor

林慶典(Ching-Tien Lin)

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

在醫療過程中，量測人體體溫機會很多，因此對體溫計的需求量相當大，故可利用微機電系統之批量生產特性，製作成低成本、可拋棄式體溫量測元件，如此可避免因量測體溫而造成病菌感染。
本體溫量測元件是以熱阻式做為感測元件的溫度量測原理，以標準半導體製程製作感測器，使用鏮銅作為柵狀金屬絲，四種不同的柵狀金屬絲寬度與距離，以比較其對感測器的性能影響。封裝後，以ANSYS建立二維模型進行熱傳分析模擬。本感測元件是位於一浮板結構上，所以也同時探討浮板結構對感測器之反應時間與靈敏度的影響。
經過ANSYS分析後了解到以下二個會影響到感測器性能的因素，一為浮板厚度，當浮板厚度小於100μm時，得到的熱平衡時間相差不多，而浮板厚度愈大者，熱平衡時間愈長，因此証實了感測器背面開孔可以有效的降低感測器本體的熱質量，提升感測器的性能。二為封裝材料厚度，封裝層的厚度愈大，感測器的熱平衡時間愈長，本研究設定的封裝厚度為100μm，經由分析模擬發現其對感測器性能的影響在可接受的範圍之內，且也可有效的保護感測元件與訊號線，如此已達到降低對感測器的影響及保護的作用了。
以下兩個因素則不會影響感測器的性能，一為柵狀金屬絲之型式，另一為金屬薄膜之厚度，因此在設計柵狀金屬絲可以增加其繞圈數，增加電阻，以加大檢出的信號，在濺鍍金屬薄膜時可選擇較小之厚度，以減少製程時間與成本。

關鍵字

微機電系統 ； 封裝 ； 熱阻式溫度感測器 ； 熱傳分析 ； 浮板 ； 半導體製程

並列摘要

The thermal-sensing elements of the body temperature sensor are resistors. The fabrication process of sensor is surface micromachining. It uses constantan as metal strips, and there are four various widths and distances between them. Then, realize their effect on the performance of the sensor. After packaged, build two dimension model with ANSYS to perform simulation and analysis of heat transfer. Then, discuss the effect of floating membrane under the thermoresistors on the response time and sensitivity of sensor.
After analysis with ANSYS, we obtain two parameters that will influence the performance of sensor. As thickness of floating membrane is less then 100μm, the heat balance time is similar. The heat balance time will raise with the increase of thickness. Therefore, we confirmed that floating membrane is efficient to reduce the thermal mass of sensor structure. The heat balance time will raise with the increase of packaging thickness. A 100μm thick packaging can protect the sensing element and wire, and the effect on the performance can be accepted.
The two following parameters will not influence the performance, type of metal strips and thickness of metal thin-film. So we can increase the number of wire to raise output signals of sensor, and reduce the thickness of metal thin-film deposition. The time and cost of manufacture will be down.

並列關鍵字

MEMS ； packaging ； thermalresistor temperature sensor ； heat transfer analysis ； floating membrane ； CMOS

參考文獻

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