集成电路钝化层薄膜的纳米力学性质研究

Nanomechanical Properties of Passivation Thin Films in Integrated Circuit

利用等离子体增强化学气相淀积工艺在p型单晶硅(111)衬底上制备了厚度为70、150、450nm的SiO2薄膜和100、1702、20 nm的Si3N4薄膜,并使用纳米压入仪对薄膜进行了纳米力学测试与分析.薄膜在不同载荷下的硬度和弹性模量计算采用Oliver-Pharr方法.在测量两种薄膜的硬度时没有发现压痕尺寸效应.SiO2薄膜的弹性模量与压入深度的依赖关系不明显,但与薄膜厚度的依赖关系较明显,薄膜厚度的增加将导致弹性模量显著减小,而Si3N4的弹性模量与薄膜厚度的依赖关系不明显,但与压入深度的依赖关系较明显,会随着压入深度的增加而逐渐增加到某一定值.

In the experiment herein, both SiO2 thin films and Si3N4 thin films were deposited by plasma enhanced chemical vapor deposition （PECVD） on p-type silicon （111） substrate. The film thickness got to 70, 150, 450 nm for SiO2, and 100, 170, 220 nm for Si3N4, respectively. A nanohardness tester was then used to conduct nanomechanical characterization on those SiO2 and Si3N4 thin films. Oliver-Pharr method was adopted in the calculation of hardness and elastic modulus of those thin films under varied loads. Hardness of SiO2 and Si3N4 films shows no indenta tion size effect. Elastic modulus of SiO2 films does not vary much with indentation depth, but shows film thickness dependence, decreasing with the increase in film thickness. Elastic modulus of Si3N4 films depends less on film thickness, but more on indentation depth, increasing to a constant value with the increase in indentation depth.