Plasma Etching Device Tapered Density Adjusting Member
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Solution Overview
Problem
Conventional plasma etching devices face challenges in achieving uniform in-plane plasma density, leading to non-uniform etching and tilting issues when processing large substrates, particularly in semiconductor manufacturing and MEMS sensor production, where high uniformity is critical for precise feature formation and mass consistency.
Innovation Solution
The plasma etching device employs a tapered plasma density adjusting member and a core member with a tapered lower end portion, combined to diffuse plasma uniformly across the chamber, ensuring a more even in-plane density distribution and reducing tilting during etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the plasma generation space is enlarged to process large substrates, then the substrate processing capability is improved, but the in-plane plasma density uniformity deteriorates due to concave density distribution
Solution Approach 1:
The plasma generation space is divided into different regions with different plasma generation characteristics. The coil is positioned to create strong plasma generation at the periphery, while the central region relies on plasma diffusion from the periphery, creating local quality differences that achieve overall uniformity
Solution Approach 2:
The coil is positioned asymmetrically relative to the plasma generation space, with the coil located at the periphery rather than centrally. This asymmetric positioning creates a plasma density distribution that compensates for the natural tendency toward concave distribution in large spaces
2Power
If RF power is applied to generate plasma in a large plasma generation space, then the plasma generation capability is improved, but the inductive electric field becomes insufficient at the central portion, worsening plasma density uniformity
Solution Approach 1:
A plasma diffusion medium (gas) acts as an intermediary to transport plasma from the periphery where the coil generates strong plasma to the central region where the inductive electric field is weak, enabling uniform plasma distribution without requiring direct inductive coupling throughout the entire space
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
This configuration significantly improves the uniformity of in-plane plasma density, enabling more uniform etching across large substrates and reducing the occurrence of tilting, thus enhancing the precision and consistency of semiconductor and MEMS sensor manufacturing.
Implementation Method 1
generates an inductive electric field by applying RF power to the coil
Implementation Method 2
generates plasma from the etching gas by the inductive electric field
Implementation Method 3
the plasma generated at a portion close to the coil is led to a central portion of the chamber and an extremely concave in-plane density of the plasma is leveled
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a substrate etching device capable of improving uniformity of in-plane density of generated plasma to uniformly etch an entire substrate surface. A plasma etching device 1 includes a chamber 2 having a plasma generation space 3 and a processing space 4 set therein, a coil 30 disposed outside an upper body portion 6, a platen 40 disposed in the processing space 4 for placing a substrate K thereon, an etching gas supply mechanism 25 supplying an etching gas into the plasma generation space 3, a coil power supply mechanism 35 supplying RF power to the coil 30, and a platen power supply mechanism 45 supplying RF power to the platen 40. Further, a tapered plasma density adjusting member 20 is fixed on an inner wall of the chamber 2 between the plasma generation space 3 and the platen 40 and, in an upper portion of the chamber 2, a cylindrical core member 10 having a tapered portion formed thereon having a diameter decreasing toward a lower end surface thereof is arranged to extend downward.