Stepped Edge Ring Geometry for Wafer Bevel Deposition Control
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Solution Overview
Problem
Conventional edge rings either fail to sufficiently suppress deposition at the bevel site of a wafer while maintaining deposition uniformity in the edge region, or they achieve good edge region uniformity at the cost of insufficient bevel site suppression.
Innovation Solution
An edge ring design featuring an annular body with a first step portion, an inclined portion, and a second step portion, along with passages that adjust the flow of backside gas to improve deposition characteristics at the bevel and edge regions of a wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional edge rings are designed to suppress deposition at the bevel site, then deposition suppression at bevel site is improved, but deposition uniformity in the edge region deteriorates
Solution Approach 1:
The edge ring is divided into multiple functional zones: a first step portion with passages for gas supply, an inclined portion for directing gas flow, and a second step portion for maintaining edge region deposition. This segmentation allows each zone to perform its specific function independently, resolving the contradiction between bevel site suppression and edge region uniformity.
Solution Approach 2:
Different regions of the edge ring are given different structures and functions: the first step portion has passages for active gas supply to suppress bevel deposition, the inclined portion creates a specific flow pattern, and the second step portion maintains proper gas distribution for edge uniformity. This local differentiation enables simultaneous achievement of both goals.
2Manufacturing precision
If conventional edge rings are designed to improve deposition uniformity in the edge region, then deposition uniformity in the edge region is improved, but deposition suppression at the bevel site deteriorates
Solution Approach 1:
The edge ring structure separates the functions of bevel suppression and edge uniformity maintenance into distinct zones. The first step portion with passages handles bevel suppression, while the second step portion ensures edge uniformity, allowing both functions to operate optimally without interfering with each other.
Solution Approach 2:
The inclined portion acts as an intermediary between the first step portion (gas supply) and the second step portion (edge region control). It directs and conditions the gas flow to achieve both bevel suppression and edge uniformity simultaneously.
3Device complexity
If a simple annular edge ring is used, then device complexity is reduced, but deposition control capability at both bevel and edge regions is insufficient
Solution Approach 1:
The edge ring is segmented into functionally distinct portions (first step portion with passages, inclined portion, second step portion), each contributing to specific deposition control tasks. This segmentation enhances control capability while maintaining a relatively simple overall annular structure.
Solution Approach 2:
The multi-portion edge ring structure performs multiple functions: gas supply, flow direction, bevel suppression, and edge uniformity maintenance, all within a single integrated component. This multi-functionality provides enhanced deposition control without requiring multiple separate devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The edge ring design effectively suppresses deposition at the bevel site while maintaining uniform deposition in the edge region, enhancing overall deposition characteristics.
Implementation Method 1
A backside gas supplied between an end portion of a wafer and an edge ring through a backside gas channel may proceed toward the inclined bottom surface of the inclined portion
Implementation Method 2
a first portion of the backside gas may pass through a through hole via a gap formed between the first bottom surface and the substrate stage to be discharged into a chamber and a remaining second portion of the backside gas may pass through a gap formed between the end portion of the wafer and the second bottom surface
Data Source
AI summary
An edge ring includes an annular body portion having a bottom surface and a top surface, a first step portion extending along an inner periphery of the body portion and having an annular first bottom surface positioned higher than the bottom surface of the body portion by a first height, an inclined portion extending along an inner periphery of the first step portion and having an inclined bottom surface extending at a first angle with respect to a first plane in which the first bottom surface is placed, a second step portion extending along an inner periphery of the inclined portion and having a second bottom surface positioned higher than the bottom surface of the body portion by a second height greater than the first height, and a plurality of passages extending outwardly from the first bottom surface of the first step portion at a second angle with respect to the first bottom surface.