Boron Carbide Sintered Body for Plasma-Etch-Resistant Focus Rings
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Solution Overview
Problem
Plasma processing apparatuses face challenges in achieving uniform plasma distribution and high plasma etch resistance due to increased plasma power causing non-uniformity and high etch rates of focus rings, leading to reduced microelectronic device quality.
Innovation Solution
A sintered body composed of boron carbide with specific grain size and carbon content distributions, combined with a controlled porosity and thermal conductivity, is used to enhance plasma etch resistance and uniformity, prepared through a method involving carbonization and multiple sintering processes at high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma power is increased to improve processing efficiency, then productivity is improved, but plasma distribution uniformity deteriorates due to wavelength effects and skin effects
Solution Approach 1:
The focus ring is designed with non-uniform grain size distribution where grains greater than 1 μm and less than or equal to 4 μm occupy 61% to 86% of the total volume, creating local variations in etch resistance across different regions of the focus ring to compensate for non-uniform plasma distribution
Solution Approach 2:
The sintered body parameters are precisely controlled including grain size distribution (61%-86% of grains between 1-4 μm), porosity (5 vol% or less), and carbon content (18-30 wt%), which collectively optimize plasma etch resistance under high power conditions
2Stability of the object's composition
If focus ring is used to improve plasma distribution uniformity, then plasma distribution uniformity is improved, but etch rate of focus ring increases leading to reduced durability
Solution Approach 1:
The sintered body parameters are precisely controlled including grain size distribution (61%-86% of grains between 1-4 μm), porosity (5 vol% or less), and carbon content (18-30 wt%), which collectively optimize plasma etch resistance under high power conditions
Solution Approach 2:
The focus ring is made from a composite sintered body combining boron carbide grains of specific size ranges with controlled porosity and carbon content, creating a material with superior plasma etch resistance compared to conventional materials
3Duration of action of stationary object
If sintered body with specific grain distribution is used to reduce etch rate, then focus ring durability is improved, but manufacturing complexity increases
Solution Approach 1:
The sintered body parameters are precisely controlled including grain size distribution (61%-86% of grains between 1-4 μm), porosity (5 vol% or less), and carbon content (18-30 wt%), which collectively optimize plasma etch resistance under high power conditions
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 sintered body achieves a low etch rate and stable plasma etch resistance, suppressing particle generation and improving the efficiency and durability of plasma processing, with an etch rate 20-32% less than silicon carbide prepared by chemical vapor deposition.
Implementation Method 1
carbonizing the molded raw material at a temperature of 500° C. to 1000° C.
Implementation Method 2
a first sintering of performing a first thermal process at a temperature of 1900° C. to 2100° C. after the carbonizing; and a second sintering of performing a second thermal process at a temperature of 2000° C. to 2230° C. after the first sintering
Data Source
AI summary
The sintered body includes boron carbide, wherein a volume ratio of grains of the boron carbide having a grain size greater than 1 μm and less than or equal to 4 μm is 61% to 86% based on a volume ratio of total grains on a surface of the sintered body.