銅的選擇性化學氣相沉積和鈦鎢合金障壁層在銅金屬結構之應用

Abstract

本論文包含兩個部分︰(1) 用選擇性的化學氣相沉積法來備製銅膜， 和(2)用TiW 來當做銅的擴散障壁。第一個部分是用有機金屬複合體 [Cu+1(hafc)•TMVS] 來當做鍍銅膜的材料。我們發現沉積壓力，基片溫 度沉積和沉積時間都是選擇性銅膜沉積的重要參數，而且三者之間是互動 的。再者，針 對銅膜在導體如(Al, TiW) 和二氧化矽 ( thermal oxide, BPSG, TEOS和 PECVD oxide)基板之間的沉積差異，我們也找到了 一些關於用選擇性的化學氣相沉積法來備製銅膜的沉積條件。第二個部分 ，研究的是TiW 和TiWNx 夾在Cu和PtSi之間擴散障壁的性質。由實驗結果 ，顯示TiW 和TiWNx 的擴散障壁效果十分明顯。Cu/TiW/PtSi /p﹢n 二極 體在經600℃ 30秒的快速退火後，其電性沒有任何退化的現象。對Cu/ TiWNx/PtSi/p﹢n的結構而言，在經過650℃、 30秒的快速退火後，其電 性還可以保持的很好。 This thesis study consists of two parts: the selective copper chemical vapor deposition (Cu-CVD) and the TiW diffusion barrier study with respect to the Cu metallization system. In the first part, selective Cu-CVD was studied using a liquid state organo- metallic compound[Cu(hfac)•TMVS] as the precursor. It is found that the deposition pressure, substrate temperature, as well as the deposition time are very important parameters for selective Cu-CVD, and correlated with one another. We have determined se- lective windows of Cu-CVD for a number of SiO2 (thermal oxide, BPSG, TEOS, and PECVD oxide) versus conductor(Al and TiW) sub- strates. In the second part of study, diffusion barrier properties of TiW and TiWNx layers were investigated. With a TiW barrier layer sandwiched between Cu and PtSi, the Cu/TiW/PtSi/p﹢n diodes were able to sustain a 30 seconds RTA annealing up to 600 ℃ without degrading the diodes' electrical characteristic. For the Cu/ TiWNx/PtSi/p﹢n diodes, the sustainable RTA temperature can be further increased to 650℃.