Electrostatic Wafer Chuck for Thin CMP Wafer Handling
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Solution Overview
Problem
Conventional vacuum suction cups for wafer chemical mechanical polishing are inadequate for handling wafers with large diameters and thin thicknesses, leading to potential damage and requiring additional adhesive layers, which complicate the process and increase maintenance needs, while ceramic suction cups are prone to clogging and frequent cleaning.
Innovation Solution
An electrostatic suction cup device with a control module that generates static electricity to securely absorb wafers without the need for adhesives, integrated with a quick-release unit for efficient transfer and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vacuum suction cup is used to suck wafer, then wafer can be transferred to polishing pad, but thin wafers are easily damaged due to insufficient stress support
Solution Approach 1:
An adhesive layer is introduced as an intermediary between the vacuum suction cup and the wafer. This adhesive layer has high bonding strength to both the suction cup and the wafer surface, allowing thin wafers to be held securely during transfer and polishing without requiring the suction cup to directly bear the full mechanical stress of the wafer.
Solution Approach 2:
The system creates a composite structure consisting of the vacuum suction cup, adhesive layer, and wafer. This composite approach combines the holding capability of vacuum suction with the structural support and stress distribution properties of the adhesive layer, enabling safe handling of ultra-thin wafers that would otherwise be too fragile.
2Reliability
If adhesive layer is applied to enhance wafer strength, then wafer can be handled more securely, but additional time and cost are required for application and removal
Solution Approach 1:
The adhesive layer is designed to be automatically applied and removed as part of the wafer handling process. The suction cup system itself performs the function of applying the adhesive to the wafer before pickup, and the adhesive is automatically removed when the wafer is released at the polishing station, eliminating the need for separate manual application and removal steps.
3Ease of operation
If ceramic suction cup is used, then wafer can be suctioned through micropores, but fine particles block the micropores requiring frequent cleaning
Solution Approach 1:
The invention employs a disposable adhesive layer that is discarded after a single use, eliminating the need to clean and maintain the suction cup. Instead of trying to maintain a complex porous ceramic structure, the system uses a simple non-porous suction cup with a disposable adhesive overlay, which is replaced rather than cleaned.
Solution Approach 2:
The adhesive function is extracted from the suction cup itself and placed in a separate, removable adhesive layer. This allows the suction cup to remain a simple, easy-to-clean non-porous component, while the adhesive properties are provided by a separate layer that can be easily replaced without affecting the suction cup structure.
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
Enhances yield and thinning effects, eliminates the need for adhesive application and removal, reduces maintenance costs, and minimizes wafer damage by providing stable and consistent suction across varying wafer thicknesses.
Implementation Method 1
the control module is capable of being used to control the electrostatic suction cup to generate static electricity to adsorb the wafer on the suction surface
Data Source
AI summary
The invention relates to an electrostatic suction cup device for wafer chemical mechanical polishing, which mainly includes a wafer carrier having a suction surface from an upper end thereof; an electrostatic suction cup arranged at the corresponding suction surface in the wafer carrier; and a control module connected to the electrostatic suction cup so that the electrostatic suction cup can be controlled by the control module to generate static electricity to adsorb the wafer to the suction surface for chemical-mechanical polishing operations. Hence, wafers can be steadily absorbed without being affected by wafer thickness to improve yield and process improvement, can remove the time and cost of gluing and film application process corresponding to strengthening the wafer strength before the wafer process, can avoid the procedure, cost and risk of debonding and film removal after the process, and can increase the practical efficacy characteristics in its overall implementation.