Adhesion measurement of thin films to a porous low dielectric constant film using a modified tape test

摘要

In the microelectronics industry,a simple tape test (ASTM 3359) is typically used to qualitatively study the adhesion of dielectric films.In this work,a a novel approach to conduct the tape test is porposed.This new method eliminates the inconsistency in the results encountered in the traditional tape test,and,at the same time,it provides both qualitative and quatitative results.This approach employs a spring-loaded mechanism and eliminates the subjective interpretation of the results of the traditional tape test.It also provides quantitative measures of the peel rate and force,factors that are relevantin the characterization of the interfacial strength of thin films.We illustrate the use of this new,modified tape test (MTT) in the study of the adhesion of multi-layered thin film structures.This study is of significance to the understanding of the damascene interconnect process integration.Thus,the adhesion of various films on the spunon porous carbon-doped silicon dioxide low dielecric constant (k) material is examined.Also,the effects of surface treatments andcuring temperature of the porous low-k films on the adhesion of the overlying oxide films are also described.An explanation of the adhesion strength with respect to the thickness of the cap layer is presented as well.