Adaptive Vacuum Clamping for Warped Substrate Stress Reduction
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Solution Overview
Problem
Conventional lithographic apparatuses induce internal stresses in substrates due to clamping forces, especially when handling warped substrates, which can negatively impact the quality of integrated circuits and overlay performance.
Innovation Solution
A substrate support system with a vacuum clamping device that includes a reduced pressure source, vacuum sections, and a control device to adapt the spatial pressure profile based on substrate shape data, ensuring stress-free clamping and proper alignment of both flat and warped substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum clamping device is used to clamp the substrate on the substrate support, then the substrate is securely held during exposure, but internal stresses are induced in warped substrates causing quality degradation and overlay errors
Solution Approach 1:
The vacuum clamping device is divided into multiple vacuum sections (first, second, third vacuum sections) with different vacuum forces applied to different regions of the substrate. The first vacuum section applies a first vacuum force, the second vacuum section applies a second vacuum force, and the third vacuum section applies a third vacuum force, where these forces are specifically tailored to accommodate substrate warpage and prevent stress concentration at any single location.
2Ease of operation
If uniform vacuum force is applied across the substrate, then clamping is simple and effective for flat substrates, but warped substrates cannot be properly shaped before clamping
Solution Approach 1:
The system performs preliminary shaping of the substrate before final clamping by applying different vacuum forces to different regions. The first vacuum section applies a first vacuum force to initially position the substrate, then the second and third vacuum sections apply different vacuum forces to shape the substrate to the desired form before exposure, ensuring the substrate is properly flattened or shaped prior to being held in the final clamped position.
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 system effectively reduces internal stresses and overlay errors by customizing the clamping pressure profile to match the substrate shape, improving the quality of integrated circuits and maintaining substrates in a desired form during exposure.
Implementation Method 1
a vacuum clamping device configured to clamp the substrate on the substrate support location, wherein the vacuum clamping device comprises: at least one reduced pressure source to create a reduced pressure, at least one vacuum section connected to the at least one reduced pressure source, wherein the at least one vacuum section is arranged and configured to attract the substrate towards the substrate support location
Data Source
AI summary
A substrate support, includes: a substrate support location configured to support a substrate, and a vacuum clamping device configured to clamp the substrate on the substrate support location, wherein the vacuum clamping device includes at least one reduced pressure source to create a reduced pressure, at least one vacuum section connected to the at least one reduced pressure source, wherein the at least one vacuum section is configured to attract the substrate towards the substrate support location, and a control device configured to control a spatial pressure profile along the at least one vacuum section with which the substrate is attracted by the vacuum clamping device, wherein the control device includes a substrate shape data input to receive substrate shape data representing shape data of the substrate to be clamped, and wherein the control device is configured to adapt the spatial pressure profile in dependency of the substrate shape data.