壓電微型感測元件在牙科植體穩固度監測上之研發

Development of a piezoelectric microsensor for monitoring the stability of dental implants

蔡明宏(Ming-Hung Tsai)

指導教授 ： 林哲堂 ； 李勝揚 ； 歐耿良

臺北醫學大學/口腔學院/牙醫學系碩博士班/碩士(2004年)

摘要

本研究以製造一微型非破壞式可植入型之牙科植體的感測元件，期能進一步與牙科植體組裝成感測裝置，以連續監測牙科植體之初期穩固度及後期骨整合程度。研究中利用高密度電漿化學氣相系統(HDP-CVD)沉積碳化矽(SiC)薄膜於P型(100)矽晶圓上，接著以溶凝膠(Sol-Gel)法製備PZT壓電薄膜，並以積體電路製程旋轉塗佈的方法將PZT壓電薄膜旋轉塗於SiC薄膜上。以常壓退火及快速退火方式對PZT壓電薄膜進行退火致使PZT壓電薄膜具壓電特性，再以微影製程(lithography)及舉離法(lift-off)製作交叉指狀電極，完成的元件分別以儀器進行薄膜及元件特性分析探討。在壓電微型感測器電性探討及評估上，則是以電阻變化及漏電流測試為主。經研究結果顯示：SiC薄膜經一小時氮氣退火後以AFM觀察發現表面有明顯結晶且存在有特定的優選方向(preferred-orientation)。GIXRD顯示經退火後SiC薄膜具(110)優選方向。剛沉積的SiC薄膜於微刻痕測試儀進行微硬度測試，其微硬度值約為50 GPa。經薄膜應力量測儀測得SiC薄膜的應力值為壓應力(compressive stress)，且應力值隨厚度的增加而增加。經由ESCA進行鍵結分析得知，未經退火處理及退火處理後的SiC薄膜之鍵結能量並無任何化學鍵結偏移產生，顯示未經退火處理及退火處理後的SiC矽薄膜並無因退火處理使得SiC薄膜與氮原子產生鍵結。此結果與SiC薄膜經微刻痕測試儀所測得的微硬度值結果是相符的。而為瞭解PZT壓電薄膜之機電耦合特性，則進行PZT壓電薄膜相對的疊層結構分析，再分別進行各項分析。以物理氣相沉積(PVD)的鉭膜於二氧化矽與PZT壓電材料作為中間層，經SEM觀察得知，鉭膜與二氧化矽及PZT壓電材料具有優越的附著能力。以PVD鍍著的鉭薄膜經TEM觀察得知，鉭薄膜為多晶相且為具低電阻率的?(bcc)體心立方結構。經四點探針測得鉭薄膜電阻值為約170 ??-cm。溶凝膠法製備PZT壓電薄膜經旋轉塗佈再以退火方式進行後處理，以X-光的繞射分析發現以快速退火後的壓電薄膜具有PZT相，且在PZT壓電薄膜的蝕刻製程中發現，在純Cl2氣體中有最佳的蝕刻效率且具平整的蝕刻壁。而經TEM觀察顯示，以PVD方式鍍著的銅電極與壓電材料薄膜及鉭薄膜界面彼此並無擴散現象，由此得知鉭薄膜能有效阻擋銅薄膜經400?C的回流製程中與壓電材料薄膜中鈦金屬與銅的交互擴散。壓電微型感測器經極化量-電場曲線的量測得知其Pr值在11.9 ~ 18.78 ?C/cm2，由此得知壓電薄膜製成的感測元件具機電耦合效應。

關鍵字

牙科植體 ； 穩固度 ； 骨整合 ； 溶凝膠法 ； PZT壓電薄膜 ； 微型感測器

並列摘要

In this study, we designed and also implemented: the integration processes of an integrated circuit for a microsensor, which can be used in monitoring the initial stability of dental implants and the process of osseointegration of bone-implant interfaces. The substrates used in these experiments were p-type (100)-oriented Si wafers with a resistivity of 5-10 ?-cm. The Si wafers were prepared through an RCA clean process. After undergoing RCA cleaning, silicon carbide was prepared using a high-density plasma chemical vapor deposition (HDP-CVD) system. A PZT thin film was prepared by the Sol-Gel method, and this method was also used for microsensor fabrication. The interdigital electrodes were fabricated by a lift-off process. Properties of the device and thin film were evaluated by physical analyses. Resistance was varied and measured with an HP4145B semiconductor parameter-analyzer to investigate the electrical properties of the microsensor. In material preparation of the PZT thin film, we had to select the best process for our experiment. The Sol-Gel process was determined to be the best for our experiment, because it is easy to control the composition and there are fewer impurities in solution. In addition, it is a low-temperature process, so this can decrease the diffusion phenomenon seen at high temperatures. Furthermore, the properties of the precursors can be varied by adjusting the viscosity and solvent contents, and various electrical properties were created. Based on the above description, the Sol-Gel process was selected for our experiment. Based on the above investigation, in order to assess the requirement of precision detection, many functional devices were integrated on a chip. Up to now, the most surface acoustic wave (SAW) microsensor devices were fabricated by abnormal IC technology. However, this results in the high cost and large-used device area. To reach cost down and promote the device performance, SAW microsensor device and transistor can be integrated on a chip. This is called system on a chip (SoC). The processes of microsensor devices and transistor must be compelled. The purpose of this study is to discuss the dental implant and osseointegration stability by SoC integration.

並列關鍵字

dental implant ； stability ； osseointegration ； Sol-Gel method ； PZT piezoelectric thin film ； microsensor

參考文獻

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