Showerhead Flow Curtain Control for Deposition Uniformity
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Solution Overview
Problem
Semiconductor device processing in multi-station chambers faces challenges in achieving uniform deposition layers due to non-uniform gas flow patterns, leading to variations in deposition thickness and profile shapes.
Innovation Solution
A method involving a secondary purge gas with varying partial pressure is used to create a flow curtain around the showerhead, adjusting the deposition process to achieve specific radial or azimuthal non-uniformities, complementing atomic layer deposition (ALD) or other processes to enhance uniformity and pattern loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deposition layer is deposited using conventional gas flow patterns through a showerhead, then the deposition process can be completed, but the deposition layer exhibits non-uniform thickness and profile variations
Solution Approach 1:
The gas flow system is segmented into multiple independent flow paths: a primary deposition gas flow through the showerhead and a secondary purge gas flow from the chamber wall. This segmentation allows independent control of each gas stream to achieve uniform deposition by compensating for edge effects and radial non-uniformities separately from the main deposition process
Solution Approach 2:
The secondary purge gas is introduced at the chamber wall to create a localized flow curtain specifically at the periphery of the showerhead. This local quality adjustment addresses the radial non-uniformity and edge effects specifically without affecting the central deposition region, enabling precise control over the deposition profile shape
2Manufacturing precision
If the secondary purge gas flow rate is increased to reduce edge effects, then the radial non-uniformity is reduced, but the deposition time increases
Solution Approach 1:
The secondary purge gas flow is applied partially - only at the periphery where edge effects occur - rather than uniformly across the entire chamber. This partial action provides sufficient control over radial non-uniformity without requiring excessive purge gas flow that would extend deposition time, thus maintaining productivity while achieving radial uniformity
3Manufacturing precision
If the showerhead is tilted to compensate for azimuthal non-uniformity, then the azimuthal uniformity is improved, but the device complexity increases
Solution Approach 1:
The mechanical tilt adjustment system is replaced with a gas flow-based solution. Azimuthal non-uniformity is compensated by introducing a secondary purge gas flow from the chamber wall that creates a flow curtain, substituting mechanical complexity with a controllable gas flow field that achieves the same uniformity improvement
4Productivity
If multiple processing stations are used in a multi-station chamber, then the productivity is improved, but the gas flow patterns become more complex leading to increased non-uniformity
Solution Approach 1:
The secondary purge gas flow system serves multiple functions simultaneously: it purges the chamber between processing stations, creates flow curtains to control radial and azimuthal non-uniformity, and maintains pressure balance across multiple stations. This multi-functionality allows the system to maintain deposition uniformity while achieving high productivity through multi-station processing
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 approach allows for controlled radial and azimuthal non-uniformities, improving deposition uniformity and reducing defects in semiconductor devices by tuning the secondary purge gas flow to match the requirements of specific processes, such as ALD or CVD, resulting in more consistent and efficient layer formation.
Implementation Method 1
A secondary purge gas is flowed during the depositing the deposition layer from a location outside of the showerhead in the processing chamber forming a flow curtain around an outer edge of the showerhead
Implementation Method 2
A deposition layer is deposited on the substrate, wherein at least one deposition gas is provided through the showerhead
Data Source
AI summary
A method for processing a substrate is provided, wherein the substrate is located below a showerhead in a processing chamber. A deposition layer is deposited on the substrate, wherein at least one deposition gas is provided through the showerhead. A secondary purge gas is flowed during the depositing the deposition layer from a location outside of the showerhead in the processing chamber forming a flow curtain around an outer edge of the showerhead, wherein the secondary purge gas comprises at least one component gas. A partial pressure of the at least one component gas is changed over time during the depositing the deposition layer, wherein the depositing the deposition layer has a non-uniformity, wherein the changing the partial pressure changes the non-uniformity over time during the depositing the deposition layer.