Multi-Wafer ALD Chamber Radial Injection Uniformity
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Solution Overview
Problem
Multi-wafer Atomic Layer Deposition (ALD) process chambers using showerhead injectors often result in reduced thickness uniformity due to axial symmetric gas precursor injection perpendicular to the substrate surface, whereas parallel injection is known to produce more uniform films, but single wafer reactors have low throughput and require frequent purging.
Innovation Solution
A multi-wafer process chamber design with partitions dividing the chamber into compartments, where substrates are rotated to sequentially expose their top surfaces to process materials and inert gases injected radially, ensuring parallel gas flow and maintaining uniformity across multiple substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If showerhead injectors are used to inject precursor gases axially symmetrically perpendicular to the substrate surface, then process time is reduced and throughput is improved, but thickness uniformity of the deposited thin films deteriorates
Solution Approach 1:
The process chamber is segmented into multiple compartments (first compartment for first precursor, second compartment for second precursor, third compartment for inert gas) separated by partitions. This segmentation allows each compartment to independently control gas flow direction, enabling radial injection in the first compartment for uniform deposition while maintaining efficient multi-wafer processing in other compartments.
Solution Approach 2:
Different regions of the process chamber are given different functional qualities: the first compartment uses radial injection geometry optimized for thickness uniformity, while other compartments may use axial injection optimized for speed. This local differentiation allows simultaneous optimization of both uniformity and throughput in different parts of the system.
2Manufacturing precision
If single wafer reactors are used with horizontal gas precursor injection parallel to substrate surface, then thickness uniformity is improved, but throughput deteriorates due to low processing capacity
Solution Approach 1:
The invention merges the advantages of single-wafer radial injection (uniformity) with multi-wafer processing capability (throughput) by combining multiple substrates on a single rotating support within one process chamber. The radial injection from the first compartment's material injector benefits all substrates simultaneously, achieving both uniformity and high throughput.
Solution Approach 2:
The process chamber is designed to perform multiple functions: it can process multiple wafers simultaneously on a rotating support, accommodate different injection geometries in different compartments, and maintain both uniform deposition and high throughput. The first compartment's radial injection system serves all substrates universally, providing uniformity across the entire multi-wafer batch.
3Productivity
If multi-wafer reactors with axial injection are used, then throughput is improved, but film uniformity deteriorates due to perpendicular gas flow direction
Solution Approach 1:
The process chamber is divided into compartments with different injection configurations. The first compartment specifically uses radial injection geometry (material injector positioned at the periphery with the axis of rotation) to ensure uniform film deposition, while other compartments can be optimized for throughput. This segmentation allows the system to achieve both uniformity and high throughput through specialized regional design.
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 design enhances the uniformity and throughput of thin film deposition by ensuring consistent exposure of substrates to process materials in a direction parallel to their surface, improving the commercial viability of multi-wafer reactors while maintaining high film quality.
Implementation Method 1
ALD is a process wherein conventional CVD processes are divided into separate deposition steps to construct the thin film by sequentially depositing single atomic monolayers in each deposition step. The technique of ALD is based on the principle of the formation of a saturated monolayer of reactive precursor molecules by chemisorption.
Implementation Method 2
A substrate support is configured to support the substrates between the first and second walls and radially inside the peripheral sidewall. The substrate support is configured to rotate the substrates relative to the peripheral sidewall in a closed path about an axis of rotation.
Data Source
AI summary
Systems and methods for depositing thin films using Atomic Layer Deposition (ALD). The deposition system includes a process chamber with a peripheral sidewall, partitions that divide a processing space inside the process chamber into at least first and second compartments, and a platter that supports substrates within the processing space. The platter rotates the substrates relative to the stationary peripheral sidewall and compartments. The first compartment receives a process material used to deposit a layer on each of the substrates. An injector, which injects the process material, communicates with the first compartment through the peripheral sidewall.