Profiled Upper Electrode for Uniform Plasma Etching
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Solution Overview
Problem
In semiconductor device fabrication, existing showerheads face issues with uniform hole formation due to pin vibration during ultrasonic drilling, leading to defects and residual by-products, particularly when processing silicon carbide materials with strong covalent bonds.
Innovation Solution
An upper electrode with a specific profiled lower surface, featuring varying thickness change rates across different radii, is designed to promote uniform plasma formation and prevent defects, incorporating single-crystal silicon with precise thickness variations to guide plasma uniformly and reduce residual by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultrasonic waves are applied to drill holes in the showerhead, then holes are formed, but pin vibration occurs causing non-uniform hole formation
Solution Approach 1:
The lower surface of the upper electrode is divided into multiple regions (central area, intermediate area, outer area) with different thickness characteristics. This segmentation allows each region to serve different functions: the central area provides support to reduce pin vibration, while the outer areas enable uniform plasma generation. The thickness varies continuously across these regions, creating a gradient structure that addresses both stability and uniformity requirements.
Solution Approach 2:
Different regions of the lower surface are given different thickness qualities tailored to their specific functions. The central area has greater thickness for structural support and vibration reduction, while the outer regions have optimized thickness for plasma uniformity. This local differentiation of properties allows the single component to simultaneously address pin stability and hole formation uniformity.
2Productivity
If the showerhead processes silicon carbide materials, then etching is achieved, but strong covalent bonds cause defects and residual by-products
Solution Approach 1:
The thickness parameter of the lower surface is continuously varied across different radial positions to optimize plasma distribution. By adjusting the thickness parameter in the central, intermediate, and outer areas, the plasma density and energy distribution are optimized to effectively break silicon carbide's strong covalent bonds while minimizing defects and residual by-products through more uniform energy delivery.
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 solution ensures uniform plasma distribution, preventing defects like scratches and chatter marks, and enhances the durability of semiconductor device fabrication apparatus by minimizing residual by-products and improving etching precision.
Implementation Method 1
ultrasonic waves are applied to the drilling plate to drill the disk
Implementation Method 2
a semiconductor etching showerhead is a device used to etch a silicon wafer by spraying gas in a plasma state onto the silicon wafer
Data Source
AI summary
An embodiment of the present disclosure provides an upper electrode including a flat upper surface; a lower surface facing the upper surface; and a thickness from the upper surface to the lower surface, wherein the lower surface includes a first profile corresponding to the central area of the lower surface and having a first thickness change rate of −0.1 to 0; a third profile surrounding the first profile and having a third thickness change rate of −0.115 to −0.122; and a fifth profile surrounding the third profile and having a fifth thickness change rate of −0.003 to 0.003, wherein the first thickness change rate, the third thickness change rate, and the fifth thickness change rate are values obtained by dividing a change in thickness by a change in radius along a horizontal direction parallel to the upper surface from a center of the lower surface.