Wafer Bonding Chuck Layout for Precise Overlay Alignment
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Solution Overview
Problem
Current bonding technologies for semiconductor devices face challenges in achieving precise overlay alignment, leading to displacement-related defects and reduced yield due to uneven deformation of wafers during the bonding process.
Innovation Solution
The bonding apparatus employs a unique chuck configuration with a non-suction area on the lower chuck to allow inward or outward deformation of the lower wafer, matching the deformation of the upper wafer, thereby reducing displacement and improving overlay precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bonding technology is used, then bonding process can be completed, but overlay alignment precision deteriorates due to uneven wafer deformation
Solution Approach 1:
The lower chuck is designed with differentiated suction characteristics: a first suction area with normal suction force and a second suction area with reduced or no suction force. This local quality differentiation allows the wafer to deform uniformly in response to thermal expansion during bonding, preventing uneven deformation that would cause overlay misalignment while maintaining overall bonding quality.
Solution Approach 2:
The chuck surface is segmented into multiple suction areas with different suction characteristics. The first suction area maintains strong adhesion for stable wafer holding, while the second suction area allows controlled deformation. This segmentation enables simultaneous achievement of wafer stability and deformation compliance for precise overlay alignment.
2Stability of the object's composition
If uniform suction is applied across the entire chuck surface, then wafer holding stability is improved, but wafer deformation uniformity deteriorates leading to displacement defects
Solution Approach 1:
The chuck employs local quality variation by creating distinct suction zones: the first suction area provides strong holding stability, while the second suction area provides reduced holding force to accommodate wafer deformation. This resolves the contradiction between stability and deformation uniformity by applying different suction qualities to different regions.
Solution Approach 2:
The chuck surface is divided into multiple suction areas with independently controllable suction forces. This segmentation allows the system to maintain overall wafer stability while permitting localized deformation in specific areas, thereby achieving both holding stability and deformation uniformity simultaneously.
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 configuration effectively suppresses defects caused by displacement in the center portion of the bonded wafer, enhancing the yield of semiconductor devices by ensuring precise alignment and bonding.
Implementation Method 1
a lower chuck configured to hold a lower wafer, with a center area in which no pin is arranged, allowing the lower wafer to deform inward or outward in the center area
Data Source
AI summary
A bonding apparatus according to an embodiment includes a first chuck, a second chuck, and a pushpin arranged in a center portion of the second chuck. The first chuck includes a first area and a second area in a plane view. The first chuck includes a first rib arranged to divide the first area and the second area from each other in the plane view. The first area includes an area that overlaps the pushpin in the plane view. The second area encircles an outer perimeter of the first area in the plane view. The first chuck has a plurality of pins arranged at intervals in the second area, and has no pin in the area of the first area that overlaps the pushpin in the plane view.