Wafer Chuck Seal Ring for Warpage Control on Large Wafers
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Solution Overview
Problem
Larger wafers in semiconductor manufacturing introduce severe warpage issues, leading to manufacturing defects such as non-uniform thickness of spun-on layers, critical dimension uniformity problems, and residual stresses causing cracks.
Innovation Solution
A workpiece holder, referred to as a wafer chuck, is designed with a chuck body and a seal ring. The chuck body has a receiving surface and multiple vacuum ports for uniform vacuum sealing. The seal ring surrounds the outermost side surface of the chuck body and is higher than the receiving surface, allowing it to lean against the tape carrier attached to the warped wafer, enhancing vacuum conditions and reducing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If larger wafers are used to hold more chips and reduce per-chip cost, then manufacturing cost per chip is reduced, but wafer warpage becomes more severe causing manufacturing defects
Solution Approach 1:
The chucking system applies different vacuum forces to different regions of the wafer. The seal ring is positioned to contact the tape carrier at specific locations, creating localized support zones that counteract warpage in critical areas while maintaining overall wafer stability for chip processing.
Solution Approach 2:
The vacuum chocking system acts as a counterforce to wafer warpage. By applying vacuum pressure through the seal ring and tape carrier interface, the system counterbalances the warping forces that cause manufacturing defects, enabling precise processing of large warped wafers.
2Ease of operation
If conventional chucking methods are used on warped wafers, then wafer handling is simple, but critical dimension uniformity and layer thickness uniformity deteriorate
Solution Approach 1:
The tape carrier serves as an intermediary between the warped wafer and the chucking system. The seal ring contacts the tape carrier rather than directly gripping the wafer, allowing the flexible tape carrier to conform to wafer warpage while maintaining a stable interface for precise processing.
3Device complexity
If vacuum sealing is applied to warped wafers without enhanced support, then chucking structure is simple, but vacuum seal effectiveness deteriorates
Solution Approach 1:
The chucking system is segmented into distinct functional components: the seal ring for vacuum sealing, the tape carrier for wafer support, and the chucking mechanism for applying force. This segmentation allows each component to be optimized for its specific function while working together to handle warped wafers effectively.
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 wafer chuck effectively reduces warpage by providing even support and vacuum force to the warped wafer, improving yield rates in subsequent processing steps and enabling handling of wafers with significant warpage up to 5000 μm.
Implementation Method 1
at least one vacuum port configured to apply a vacuum seal
Data Source
AI summary
A workpiece holder includes a chuck body and a seal ring. The chuck body includes a receiving surface configured to receive a workpiece and at least one vacuum port configured to apply a vacuum seal. The seal ring surrounds a side surface of the chuck body. A top surface of the seal ring is higher than the receiving surface of the chuck body, and the workpiece leans against the seal ring when the vacuum seal is applied between the workpiece and the chuck body.