Substrate Support Positioning for Edge Uniformity
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Solution Overview
Problem
High-pressure sputtering in semiconductor process chambers leads to non-uniform deposition at the edge of substrates due to deposition buildup on the cover ring, affecting edge deposition uniformity.
Innovation Solution
The method involves maintaining a consistent shadow effect on the substrate edge by adjusting the substrate support's position relative to the cover ring, compensating for deposition on the cover ring's top surface through vertical movement, weighing, kilowatt-hours of sputtering target usage, and using a controller to maintain deposition uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure sputtering is used to deposit material on substrates, then deposition rate is improved, but deposition uniformity at the substrate edge deteriorates due to buildup on the cover ring
Solution Approach 1:
The substrate support is made dynamically adjustable in the vertical direction, allowing real-time compensation for cover ring deposition buildup. The system transitions from a static configuration to a dynamic one where the substrate support position can be modified based on measured deposition thickness, thereby maintaining edge uniformity while using high-pressure sputtering processes.
Solution Approach 2:
A feedback mechanism is implemented where the thickness of deposition on the cover ring is measured (e.g., via weighing the cover ring), and this measurement is used to automatically adjust the substrate support position. This closed-loop control ensures that edge deposition uniformity is maintained despite continuous deposition processes that cause cover ring buildup.
2Device complexity
If the cover ring remains stationary while deposition occurs, then device simplicity is improved, but shadow effect changes causing edge uniformity to deteriorate
Solution Approach 1:
Instead of making the cover ring movable (which would increase complexity), the system dynamically adjusts the substrate support position. This approach maintains relative simplicity while achieving the necessary dynamic compensation for shadow effect changes caused by cover ring deposition buildup.
3Manufacturing precision
If substrate support position is adjusted frequently to compensate for deposition, then edge uniformity is improved, but processing time increases
Solution Approach 1:
The substrate support position adjustment is implemented as a periodic action rather than continuous adjustment. The system measures cover ring deposition thickness at intervals (e.g., after processing a certain number of substrates or based on weight threshold changes) and adjusts the substrate support position accordingly. This periodic compensation maintains edge uniformity while minimizing interruptions to the deposition process.
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 ensures consistent edge deposition uniformity by compensating for the increased shadow effect caused by deposition buildup on the cover ring, reducing non-uniformity issues and maintaining uniformity throughout the substrate processing.
Implementation Method 1
The process chamber may have a sputtering target that is powered by RF and/or DC power to deposit the target material on a wafer
Implementation Method 2
a deposition ring that surrounds a substrate support and a cover ring that rests on the deposition ring
Implementation Method 3
maintaining a shadow effect in relation to an edge of a substrate
Data Source
AI summary
A movable substrate support with a top surface for holding a substrate, when present, is used in conjunction with a cover ring that is stationary to adjust for a shadow effect to control substrate edge uniformity during deposition processes. The cover ring is held stationary by an electrically isolated spacer that engages with a grounded shield in the process volume of a semiconductor process chamber. A controller adjusts the substrate support in response to deposition material on a top surface of the cover ring to maintain the shadow effect and substrate edge uniformity.