低熔點基板上主動式元件關鍵製程開發

Abstract

利用複晶矽薄膜電晶體製作主動式陣列顯示器及周邊驅動電路於玻璃或塑膠等低熔點基板已是目前及未來平面顯示器的趨勢，然而受限於低熔點基板上的製程溫度，高品質的複晶矽薄膜電晶體製程相當困難。在本論文中，我們提出一種新的基板轉移技術利用背向蝕刻的方式，可將元件由矽基板上轉移到玻璃或是塑膠等低熔點基板上。 首先，用傳統的矽基板製程技術將高品質的複晶矽薄膜電晶體製作在矽基板上，接著將做好的複晶矽薄膜電晶體黏貼在玻璃或是塑膠等低熔點基板上。先用化學式機械研磨（CMP）再搭配濕式蝕刻溶液，或是完全使用濕式蝕刻溶液來將背面的矽基板蝕刻。使用完全濕式蝕刻溶液蝕刻是為了避免化學式機械研磨（CMP）時對可撓曲基板的傷害，並開發出最佳化的濕式蝕刻條件。我們由複晶矽薄膜電晶體的電特性可證明此背向蝕刻的基板轉移技術之可行性，其製程技術對元件幾乎不會產生傷害。此外，在論文中我們也討論了多種矽蝕刻溶液的特性。 利用此背向蝕刻的基板轉移技術可以突破在低熔點基板上製程溫度的限制。結合傳統CMOS的製程，我們可以在低熔點基板上做出極高品質的複晶矽薄膜電晶體。

The active matrix liquid-crystal display (AMLCD) and peripheral drivers combined with the high performance poly-Si TFTs on the glass/plastic or other low melting substrates is the trend now. Nevertheless, the process temperature limitation on the low-melting substrates is still a serious issue. In this thesis, a novel Devices Transfer Technology by Backside Etching (DTTBE) method that makes it possible to transfer thin-film devices from Si wafers to glass or plastic substrate has been investigated. This method breaks though the process temperature limitation on the low-melting substrates. First, high performance poly-Si TFTs were fabricated on the Si wafer and then adhered to glass or plastic substrates. The remaining Si was removed delicately using wafer backside CMP and wet chemical etching or only entire chemical wet etching without CMP. Besides, in order to achieve the chemical silicon thinning process, for flexible substrates various silicon etchers were investigated in this thesis. In both methods of backside thinning the transferred devices exhibit no electrical degradation or yield loss in our research. Therefore, for high-quality display application on low-melting temperature substrates, the novel transfer technique is quite attractive because of no process temperature limitation and its fully compatibility with conventional CMOS technology.