離子佈植對低介電常數材料之特性影響與在銅連線上之應用

Abstract

本篇主要是研究利用離子佈植的方法，在低介電常數材料（MSQ）裡面形成銅擴散阻障層，以應用低介電常數材料於銅導線間防止銅擴散的產生，使銅導線間的漏電流降到最低，同時降低介電常數。 這裡的離子佈植，我們使用氟、氮、氫 三種離子植入MSQ膜裡面，實驗發現氟離子植入確實能使介電常數降低到2以下，而氮離子植入也如預料中，能使漏電流降到最低。其中的原因，應該是植入後的氟離子和MSQ膜形成Si-F鍵結，使介電常數降低，又植入後的氮離子和MSQ膜形成Si-N鍵結，使銅不易擴散到介電層中，因而不易產生漏電流。

This thesis studies method of using ion implantation on Low-k materials to form a barrier layer of copper diffusion, and apply to suppress copper diffusion on copper interconnection. It makes the leakage current and dielectric constant become lower at the same time. We use three ions of F、N、H on the film of MSQ. The experiment finds that ion implantation of F indeed reduce the dielectric constant below 2, and ion implantation of N and our expectancy are the same that makes the leakage current lowest. The reason is that ion implantation of F and the film of MSQ form bonds of Si-F to make the dielectric constant lower, and ion implantation of N and the film of MSQ form bonds of Si-N to suppress copper diffusion on dielectric layer and to reduce leakage current.