Wafer Joining Chuck with Segmented Texture for Flatness and Separation
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Solution Overview
Problem
In three-dimensional integration of semiconductor devices, vertical distortion occurs due to uneven surfaces of chucks used in joining wafers, leading to challenges in maintaining flatness and separating wafers after bonding.
Innovation Solution
A joining device with a first holding member for vacuum-sucking a first substrate and a second holding member with pins and an outer wall to support the second substrate, ensuring appropriate flatness and easy separation by controlling the flatness of the chuck surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the upper surface of the lower chuck is subjected to lapping or mirror treatment to make it flat, then the flatness of the chuck surface is improved, but the surface texture becomes too fine causing the lower wafer to be hardly separated from the lower chuck
Solution Approach 1:
The lower chuck surface is segmented into multiple regions with different textures: a first region with fine texture (for flatness) and a second region with coarse texture (for easy separation). This segmentation allows each region to serve its specific function without compromising the other.
Solution Approach 2:
Different portions of the lower chuck surface are given different local qualities (textures). The first region has a fine texture to provide flatness, while the second region has a coarse texture to facilitate easy separation. This local differentiation resolves the contradiction between flatness and ease of separation.
2Ease of operation
If the lower chuck surface is made uneven due to irregularities or particles, then the ease of separation is improved, but vertical distortion is generated in the joined superposed wafer
Solution Approach 1:
The lower chuck surface is divided into distinct functional zones: a first region providing flatness through fine texture, and a second region providing easy separation through coarse texture. This prevents the entire surface from being either too smooth or too rough.
Solution Approach 2:
Different local areas of the chuck surface are assigned different textures based on their functional requirements. The first region maintains fine texture for flatness, while the second region has coarse texture for separation, eliminating the need for overall surface unevenness.
3Manufacturing precision
If the flatness of the lower chuck is transferred to the lower wafer during joining, then the flatness is maintained, but vertical distortion occurs in the joined superposed wafer
Solution Approach 1:
The lower chuck surface is segmented into a first region with fine texture that transfers flatness to the wafer, and a second region with coarse texture that does not contact the wafer during joining. This ensures flatness transfer without vertical distortion.
Solution Approach 2:
Only the first region with fine texture contacts the wafer during joining, providing the necessary flatness transfer. The second region with coarse texture remains non-contacting, preventing vertical distortion while still facilitating easy separation after joining.
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 suppresses vertical distortion in joined substrates, allows for precise alignment, and facilitates easy separation of wafers, enhancing the joining process efficiency.
Implementation Method 1
a first holding member configured to vacuum-suck a first substrate to draw and hold the first substrate on a lower surface thereof, and a second holding member disposed below the first holding member and configured to vacuum-suck a second substrate to draw and hold the second substrate on an upper surface
Implementation Method 2
The upper wafer drawn and held by an upper chuck and the lower wafer drawn and held by a lower chuck are joined together by the Van der Waals force and by a hydrogen bond (an intermolecular force)
Implementation Method 3
The upper wafer drawn and held by an upper chuck and the lower wafer drawn and held by a lower chuck are joined together by the Van der Waals force and by a hydrogen bond (an intermolecular force)
Data Source
AI summary
A joining device for joining substrates together includes a first holding member configured to vacuum-suck a first substrate to draw and hold the first substrate on a lower surface thereof, and a second holding member disposed below the first holding member and configured to vacuum-suck a second substrate to draw and hold the second substrate on an upper surface thereof. The second holding member includes a body portion formed into a size larger than the second substrate when seen in a plan view and configured to vacuum-suck the second substrate, a plurality of pins provided on the body portion and configured to make contact with a rear surface of the second substrate, and an outer wall portion annularly provided on the body portion at an outer side of the plurality of pins and configured to support an outer periphery portion of the rear surface of the second substrate.