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Method for a pin up, post etch, in place ashing/cleaning process

IP.com Disclosure Number: IPCOM000022272D
Publication Date: 2004-Mar-03
Document File: 3 page(s) / 42K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a pin up, post etch, in place ashing/cleaning process. Benefits include improved functionality and improved yield.

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Method for a pin up, post etch, in place ashing/cleaning process

Disclosed is a method for a pin up, post etch, in place ashing/cleaning process. Benefits include improved functionality and improved yield.

Background

         During conventional radio frequency (RF) plasma etching, the wafer is typically held on to the lower electrode through mechanical methods or an electrostatic charge (see Figure 1). A polymer is formed at the front, side, and back of the wafer’s beveled edge. Conventional in-place ashing methodologies cannot efficiently remove this polymer build-up (see Figure 2). The wafer sits on the electrode where the side and back of the wafer bevel edge are not exposed to the ashing/cleaning process chemistry. The unwanted polymer interacts with silicon nitride and other interlayer dielectric (ILD) materials. The polymer falls off during subsequent processing steps, which can result in ~200 lost dice/wafers.

         The conventional process can be implemented using the following steps (see Figure 3):

1.         Etch

2.         In-place ashing
3.         Wet clean

Description

         The disclosed method is a pin up, post etch, in place ashing/cleaning process. After etch, the wafer is lifted up and away from the lower electrode (see Figure 4). The edge of the wafer is fully exposed to the ashing/cleaning process chemistry. With the wafer bevel edge now exposed to the ashing plasma, the polymer can be easily cleaned (see Figure 5).

         The disclosed method can be implemented using the following steps (see Figure 6):...