Hybrid Vacuum-Electrostatic Chuck Carrier for High-Warpage Wafers
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Solution Overview
Problem
Existing electrostatic chucks and vacuum chucks are ineffective in fully flattening highly warped semiconductor wafers, especially in vacuum processing environments, leading to inaccuracies in imaging and processing operations.
Innovation Solution
A hybrid vacuum-electrostatic chuck carrier that uses both vacuum and electrostatic forces to clamp and flatten highly warped wafers, initially securing them in a load lock chamber at atmospheric pressure and then transferring them under vacuum to a main processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrostatic chuck is used to flatten wafers, then flattening capability is improved for slightly or moderately warped wafers, but effectiveness deteriorates for highly warped wafers
Solution Approach 1:
The patent combines vacuum chucking and electrostatic chucking into a hybrid system. The vacuum chuck provides initial clamping and flattening for highly warped wafers, while electrostatic chucking maintains the flattened state during vacuum processing. This merging of two different chucking mechanisms resolves the limitation of electrostatic chucks alone being ineffective for highly warped wafers.
2Reliability
If vacuum chuck is used to secure and flatten wafers, then effectiveness is improved for highly warped wafers, but usability deteriorates in vacuum processing chambers
Solution Approach 1:
The hybrid chuck merges vacuum chucking and electrostatic chucking functionalities. The vacuum chuck component provides effective clamping for highly warped wafers, while the electrostatic chuck component enables operation in vacuum processing chambers by maintaining the clamped state without requiring atmospheric pressure differential.
Solution Approach 2:
The system changes the operational parameters by using vacuum chucking at atmospheric pressure for initial clamping, then transitioning to electrostatic chucking when transferring to the vacuum chamber. This parameter change allows the system to maintain effectiveness across different pressure environments.
3Device complexity
If traditional electrostatic chuck is used in vacuum chamber, then device simplicity is maintained, but flattening capability deteriorates for highly warped wafers under vacuum conditions
Solution Approach 1:
The patent integrates vacuum chucking and electrostatic chucking mechanisms into a single hybrid chuck structure. This merging allows the system to achieve high flattening accuracy for highly warped wafers under vacuum conditions while maintaining reasonable device complexity through a unified 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
Ensures precise flattening of warped wafers, maintaining accurate working distances for imaging and processing, even in high or ultra-high vacuum conditions, by combining vacuum and electrostatic clamping techniques.
Implementation Method 1
clamping and flattening the substrate to the substrate holder by applying a vacuum to the one or more vacuum channels
Implementation Method 2
applying a voltage to the one or more electrodes to further clamp the substrate to the substrate holder with an electrostatic force
Data Source
AI summary
A method of processing a substrate comprising: positioning the substrate on an upper surface of a substrate holder in a first chamber, wherein the substrate holder comprises one or more vacuum channels disposed at the upper surface and one or more electrodes disposed within the substrate holder proximate to the upper surface; while the substrate holder is within the first chamber, clamping and flattening the substrate to the substrate holder by applying a vacuum to the one or more vacuum channels; while the substrate is clamped to the substrate holder via the one or more vacuum channels, applying a voltage to the one or more electrodes to further clamp the substrate to the substrate holder with an electrostatic force; pumping out the first chamber to a vacuum pressure while continuing to clamp the substrate to the substrate holder with electrostatic force; while the substrate is clamped to the substrate holder by electrostatic force, transferring the substrate holder from the first chamber into a second chamber under vacuum conditions; and while the substrate holder is within the second chamber, maintaining the electrostatic force clamping the substrate to the substrate holder, and processing the substrate in the second chamber at a vacuum pressure.