Showerhead Gas Injection Module for Uniform Etching
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Solution Overview
Problem
The etching process in semiconductor device fabrication is compromised due to differences in flow rates and pressures between central and peripheral injection holes of a showerhead, leading to non-uniform etching of substrates.
Innovation Solution
A gas injection system with a flow rate controller that maintains similar pressures and flow rates through first and second injection holes on the showerhead, using pressure sensors and valves to equalize gas flow across the substrate processing apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If gas is injected through multiple injection holes in a showerhead, then gas distribution coverage is improved, but pressure differences between central and peripheral regions cause non-uniform flow rates
Solution Approach 1:
The patent applies local quality by differentiating the showerhead into multiple regions (central region with first injection holes and peripheral region with second injection holes) with different structural characteristics. Each region has specifically designed passage cross-sectional areas to compensate for pressure differences, ensuring uniform gas flow distribution across the entire substrate surface despite the large coverage area.
2Area of stationary object
If injection holes are distributed across a large showerhead area, then gas coverage is improved, but pressure equalization becomes difficult
Solution Approach 1:
The patent segments the gas distribution system into multiple independent regions (first region with central injection holes, second region with peripheral injection holes), each with dedicated gas passages. This segmentation allows independent pressure control and flow optimization for each region, managing the complexity of pressure equalization across large areas by treating each segment separately rather than as a single unified system.
Solution Approach 2:
The patent changes the parameter of passage cross-sectional area to control gas flow distribution. By adjusting the cross-sectional areas of passages in different regions (making peripheral passages larger than central passages), the system compensates for pressure differences and achieves uniform gas flow across the entire showerhead area without requiring complex active pressure control mechanisms.
3Quantity of substance
If passage cross-sectional areas are increased to improve gas flow, then gas delivery capacity is improved, but pressure control precision deteriorates
Solution Approach 1:
The patent applies local quality by assigning different passage cross-sectional areas to different regions based on their specific requirements. Central passages have smaller cross-sectional areas while peripheral passages have larger cross-sectional areas, creating locally optimized flow characteristics that compensate for pressure gradients and maintain uniform gas flow rate distribution across the entire substrate surface.
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
Ensures uniform etching of substrates by maintaining consistent gas flow rates and pressures across the substrate, enhancing etch uniformity and processing quality.
Implementation Method 1
a flow rate controller configured to maintain pressure within the first upper passages relative to pressure in the second upper passages such that gas, introduced into the showerhead via the gas distributor, flows through the first injection holes at a rate similar to that at which gas flows through the second injection holes
Data Source
AI summary
A gas injection module includes a showerhead having first injection holes on a first region of the showerhead and second injection holes on a second region of the showerhead, the second region being outside the first region, a first distribution plate on the showerhead and having first and second upper passages respectively connected to the first and second injection holes, and a flow rate controller on the first and second upper passages of the first distribution plate. The flow rate controller reduces a difference in pressure within the first and second upper passages so that the gas may have similar flow rates within the first and second injection holes.