Plasma Etching Chamber with Ion Removal for Uniform Substrate Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma etching apparatuses struggle to uniformly etch substrates that are primarily etched by either ions or chemical reactions with radicals, as uniform plasma density does not account for varying etching rates across the substrate surface, leading to non-uniform etching and inaccuracies in feature formation.
Innovation Solution
The method involves a vertically divided processing chamber with an upper and lower chamber, where the pressure is reduced, and the etching gas is excited into plasma in both chambers, with RF power applied to the platen to generate a bias potential. Ions are removed using an ion removing means, such as a grounded plate or magnetic field, allowing radicals to concentrate at the central portion without altering plasma density, ensuring uniform etching across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform plasma density is used across the substrate surface, then the device complexity is reduced and operation is simplified, but the etching uniformity deteriorates due to varying etching rates at different substrate positions
Solution Approach 1:
The patent implements different plasma densities at different substrate positions by dividing the processing chamber into multiple regions with independent plasma generation control. The central region has higher plasma density while peripheral regions have lower plasma density, allowing each region to be optimized for its specific etching requirements and achieving uniform etching across the entire substrate surface
Solution Approach 2:
The processing chamber is segmented into multiple plasma generation regions that can be independently controlled. This segmentation allows the system to manage complex plasma density distributions by breaking down the overall control into manageable regional units, each with its own plasma generation parameters
2Productivity
If ion density is increased to improve etching rate, then productivity increases, but the harmful effects of ion damage to the substrate increase
Solution Approach 1:
The patent extracts ions from the plasma before they reach the substrate surface using an ion removal unit. This allows the system to maintain high radical density for efficient chemical etching while removing the harmful ion component that would otherwise cause substrate damage, achieving high productivity without ion damage
Solution Approach 2:
The ion removal unit acts as an intermediary between the plasma generation region and the substrate. It selectively removes ions from the plasma flow while allowing radicals to pass through to the substrate, mediating the interaction between plasma and substrate to achieve beneficial etching without harmful ion effects
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 approach allows for uniform etching of substrates regardless of whether they are primarily etched by ions or radicals, maintaining consistent etching rates and feature perpendicularity across the entire substrate surface.
Implementation Method 1
a pressure within the processing chamber is reduced by exhaust means
Implementation Method 2
a processing gas including an etching gas is excited into a plasma by plasma generating means
Implementation Method 3
RF power is supplied to a platen by power supply means to generate a bias potential
Implementation Method 4
ions are removed using an ion removing means, such as a grounded plate or magnetic field
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
The present invention relates to a plasma etching apparatus capable of uniformly etching the entire surface of a substrate regardless of the kind of the substrate. A plasma etching apparatus 1 has a processing chamber 11 in which the outer diameter of an upper chamber 12 is formed smaller than a lower chamber 13 and the upper chamber 12 is provided at the central portion of the top surface of the lower chamber 13, a grounded plate-shaped member 14 which is provided on the ceiling of the lower chamber 13 to divide the inner space of the processing chamber 11 and which has a plurality of through holes 14a penetrating from the top surface to the bottom surface thereof, a platen 16 which is disposed in the lower chamber 13 and on which a substrate K is placed, a gas supply device 20 for supplying an etching gas into the upper chamber 12, plasma generating devices 26, 29 for exciting etching gases in the upper chamber 12 and in the lower chamber 13 into a plasma, respectively, an exhaust device 35 for reducing the pressure within the processing chamber 11, and an RF power supply unit 32 for supplying RF power to the platen 16.