- 學位論文
由銅/鋁/鈦/矽結構組成蕭特基二極體的電遷移研究
ElectromigrationStudy on Cu/Al/Ti/Si Schottky Diodes
摘要
本論文主要研究在市售標準蕭特基二極體（Schottky diode）架構的產品於高溫和高電流密度的交互作用下其電遷移效應及伴隨反應生成的介金屬化合物（Intermetallic Compounds, IMCs）形成狀況。此研究所使用的蕭特基二極體為由銅導線、鋁金屬層、鈦阻障層及N型矽基板的結構所組成，而介金屬化合物的生成主要是發生在銅焊線和鋁金屬層的介面處，在過去的文獻裡，關於銅鋁金屬的介金屬化合物研究已有很多文獻探討其特性和現象，但大部分為高溫實驗無外加電流，或為厚金屬層/金屬墊層（Under Bump Metallurgy, UBM）的樣品，與實際焊線封裝製程產品包含運用時的高溫附加電流環境下，有一定程度的差異，尤其是在電流的加乘效應下，介金屬化合物的生成勢必會更加快速，本研究即是在這議題下設定進行。 本次試驗所使用的溫度為 125℃ 及150℃，電流分別為0A、0.8A和1.2A的環境條件下進行，將一定數量的樣品個別外加電流，置於設定好實驗溫度的烤箱中，每間隔672小時取樣品一次，每次取5個樣品為一實驗資料點，最長實驗的時間有持續到4032小時，依結果比較可分兩組為，1、在相同0.8A電流下不同溫度125℃及150℃的結果比較和 2、相同溫度150℃在不同電流0.8A和1.2A下的結果比較，以上為3個實驗條件，再加上125℃/0A的參考條件，本試驗總共有四組條件進行。 在本研究中，可證實外加電流會加速介金屬化合物的生成反應，且外加電流越高加速越快，然而相較電流對的介金屬化合物的生成速度的影響，環境溫度所帶來的效果是更加的顯著，提高溫度所增加的生成速度比提高電流來的多，證實了環境溫度為主要介金屬化合物生成的影響因素。而至於其失效模式，我們可以結論為電子風力增加了鋁金屬擴散進入銅打線中形成銅鋁介金屬化合物的速率，而之後空洞（Void）便在銅鋁介金屬化合物與鈦阻障層的介面處形成，最後導致二極體電性失效。
並列摘要
In this research, we studied the electromigration effect on commercial Cu/Al/Ti/Si schoottky diodes. The structure of Schottky diode consisted of copper wire bonds, aluminum metal pads, Titanium barrier layers and N type silicon substrates. The reaction of intermetallic compounds happens in the interface between copper wire bonding and aluminum metal pad. Although, there already have many articles researches on the reaction of copper- aluminum intermetallic compounds, only few studies focused on electromigration. The experimental condition in this study were: temperature 125℃ and 150℃, stressing current were 0.8A and 1.2A. We placed desired numbers of samples in an oven then applied electrical current individually to each sample. We did a sampling on 5 units in every 672 hours as one data point of the experiment condition. The experiment could last to 4032 hours if no failure occurs. This study can be divided into two groups. 1. the comparison between 125℃ and 150℃ under the same 0.8A current stressing; 2. the comparison between 0.8A and 1.2A under the same temperature at 150℃. There were four conditions in this study including above listed three conditions from two groups and one additional 125℃/0A as baseline condition. From the results of this study, we concluded that the current stressing increases the reaction rate of intermetallic compounds. And yet in term of the influence to intermetallic compounds reaction. The temperature has more significant influence on the reaction rate. The reaction rate increased as the increase in temperature. The failure mode for the Schottky diodes is concluded as follow: electron wind force enhanced the dissolution of the Al film into the Cu bonds then increased the forming rate of the Cu/Al IMCs. Therefore, voids formed in the interface of IMCs and Ti layer, resulting in the failure of diodes.
參考文獻
延伸閱讀
- 蔡富鈞（2009）。鈦/鋁金屬與氧化鋅-氧化銦錫共濺鍍薄膜歐姆接觸及其應用於蕭特基二極體之研究〔碩士論文，國立虎尾科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0028-2307200917594800
- 陳冠銓（2023）。銅片成長銅氧化物與常壓電漿沉積二氧化鈦異質奈米結構於光電化學產氫之應用研究〔碩士論文，義守大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0074-1101202311210200
- 楊致瑋（2012）。金屬-絕緣體-半導體結構之二氧化鈦光檢測器元件研製〔碩士論文，國立虎尾科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0028-2507201212215400
- Tseng, C. C., Chu, F. S., & Lin, J. C. (2002). Modeling, Simulation and Device Fabrication of Schottky Diodes. 華岡工程學報, (16), 175-189. https://doi.org/10.29987/CCUHKJE.200206.0010
- 凃宗賢（2012）。A study on the Ag/n-ZnO thin film Schottky diode〔碩士論文，崑山科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0025-2102201217410700