超薄化矽轉移與氧化矽接合在背照式感光元件上之應用

Abstract

本論文呈現三維積體電路技術之超薄矽晶圓薄膜轉移以應用於背像式互補式金氧半導體影像感測器。此超薄晶圓轉移技術可有效增加感測晶片的畫素以及更高的曝光強度。為了進一步控制各個單一製程參數，首先簡化元件製作並且開發一套可應用於背向互補金氧半導體影像感測器測試之平台。此平台最為關鍵的技術即是晶圓級氧化矽接合以及超薄化矽晶圓轉移。首先，在晶片鍍上同樣厚度的氧化矽，利用不同的二氧化矽組合配上前處理以選定適當的氧化矽材料做為接合層。接著進行晶圓級氧化矽接合，改變接合中的參數，如溫度、接合力道、給予力道方式、前處理方式、氧化矽種類，利用超音波檢測影像可得到合適的晶圓級氧化矽接合參數。另一項矽薄膜轉移製程技術部分，將氫離子植入後並且進行250度30分鐘二氧化矽接合，利用SIMS觀測氫離子植入位置。接著在退火製程過後將矽轉移到另一塊晶片，使用FIB/TEM圖形影像分析轉移後之矽薄膜，發現並沒有缺陷存在，可證明是一良好的轉移方式，並且製程溫度可全程在400度下進行。此超薄化晶圓轉移測試平台搭配高品質晶圓級二氧化矽接合，經過檢測證實可應用在背向式金氧半影像感測器元件製作。

Ultra-thin silicon wafer layer transfer using three-dimension integration circuits (3D-ICs) technologies for the application of backside illumination CMOS image sensor (BSI-CIS) is presented in this thesis. This ultra-thin silicon wafer transfer technology can not only efficiently enhance the pixel number of CMOS image sensor but also achieve higher exposure intensity. In order to further control each process parameter, a simplified test vehicle, which provides the ability to apply to BSI-CIS and component fabrication, was developed. The key technologies of this simplified test vehicle include wafer-level oxide bonding and ultra-thin silicon wafer layer transfer. For oxide bonding technology, different oxide species with different pre-treatment before bonding was selected to investigate the corresponding chip-level bond quality for the oxide bond material candidate. After the species was determined, wafer-level oxide bonding under different bonding process parameters, such as bonding temperature, bonding pressure, given force type, pre-treatment solution and oxide species, was studied. Finally, with inspection results of scanning acoustic tomography (SAT), a suitable wafer-level oxide bonding parameter can be achieved. Another key technology in the simplified test vehicle is ultra-thin silicon transfer process, H+ ions were implanted, followed by the oxide bonding at 250 ℃ for 30 min. Secondary ion mass spectrometry (SIMS) data was employed to investigate the position of H ions. The ultra-thin silicon layer transfer was accomplished after annealing. The FIB/TEM images show no obvious defects in the transferred Si layer, indicating a good method for silicon layer transfer with whole process temperature below 400 ℃. This ultra-thin silicon layer transfer simplified test vehicle using high quality wafer-level oxide bonding is successfully demonstrated and shows the potential for the fabrication of BSI-CIS application.