AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP2
Etching Characteristics of Organic Polymers by Plasma Beam Irradiation

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: K. Kurihara, Toshiba Corp., Japan
Authors: K. Kurihara, Toshiba Corp., Japan
A. Egami, Association of Super-Advanced Electronics Technologies, Japan
M. Nakamura, Association of Super-Advanced Electronics Technologies, Japan
Correspondent: Click to Email
Copper interconnection and low-k dielectric interlayer are promising technologies for reducing the RC delay of LSI devices. Organic polymers such as SiLK and GX-3 are one of the candidates of the low dielectric materials. The chemical formulas of these materials have not been clearly opened to the public due to company secrets. It is, therefore, difficult to forecast the characteristics of etching behavior based on the experience. It is important to investigate the relation between the etching behavior and the chemical formulas of organic material for understanding of the fundamental etching mechanisms. In this study, we prepared three kinds of organic films whose compositions were clearly identified. They were methacrylate polymer films, which were polytbutylmethacrylate (PtBuMA), polycyclohexylmethacrylate (PCHMA) and polybenzylmethacrylate (PBMA). The chemical formulas of these films have the same main chain with a different side chain. We investigated the etching characteristics such as etching yield (EY) using a plasma beam irradiation apparatus which can control the plasma parameters precisely. The etch yields of PCHMA and PBMA increased with increase in the ion energy and were saturated over around 330 eV. The etch yield of PtBuMA did not depend on the ion energy above 130 eV. These etch yield behaviors look like the other organic materials such as GX-3 and this can be the notable etching characteristics of organic films. Furthermore we measured desorbed products during nitrogen plasma etching by using a time-of-flight technique. Major desorbed products were HCN and C@sub 2@N@sub 2@ for all organic films we used, and very small amount of C@sub 6@H@sub5@ which is a part of the side chain was also observed in the case of PBMA etching. We will discuss the etching characteristics of organic material based on surface analysis using an in-situ X-ray photoelectron spectroscopy and an energy distribution of the desorbed products. This work was funded by NEDO.