Wafer Support Plate Recess Bonding for Thin Wafer Separation
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Solution Overview
Problem
Existing methods for thinning device wafers to a thickness of 50 μm to 100 μm face challenges in handling and material constraints due to the use of adhesives and support plates that require UV or laser permeability, limiting material choices.
Innovation Solution
A processing method involving forming a recess on the support plate, applying resin to the recess, and using a cutting blade or laser to reduce bonding force, allowing separation without UV or laser exposure, thus eliminating adhesive residue and material constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ultraviolet-curable resin is used as adhesive and ultraviolet rays are applied to reduce bonding strength, then the wafer can be separated from the support plate, but material constraints are imposed on the support plate requiring it to be made of UV-permeable material such as glass
Solution Approach 1:
The adhesive bonding area is segmented into two distinct regions: a first adhesive region in the outer circumferential area that allows UV penetration for bond reduction, and a second adhesive region in the central device area that remains intact. This segmentation enables differential treatment of adhesive regions, allowing UV separation in the outer region while preserving adhesive strength in the device region.
Solution Approach 2:
Different properties are applied to different regions of the adhesive layer. The outer circumferential region is designed to be UV-permeable for bond reduction and separation, while the central device region maintains strong bonding. This local differentiation resolves the contradiction by allowing UV-based separation processes while protecting the device region from adhesive residue and UV damage.
2Productivity
If wafers are thinned down to a thickness of 50 μm to 100 μm, then the wafer meets modern electronic appliance requirements, but the wafer becomes more susceptible to damage during delivery and handling
Solution Approach 1:
The wafer is thinned down to the required thin thickness before the separation process. By completing the thinning operation while the wafer is still firmly bonded to the support plate in the second adhesive region, the wafer is protected from damage during subsequent handling and separation. The support plate acts as a protective carrier throughout the thinning and separation processes.
Solution Approach 2:
The support plate serves as an intermediary carrier that protects the thinned wafer during handling and separation. The differential adhesive design allows the wafer to be securely held during thinning, then selectively separated in the outer region while the central device region remains protected by the adhesive bond to the support plate.
3Ease of manufacture
If an annular recess is formed in the support plate and adhesive is supplied to it, then the wafer can be affixed to the support plate, but adhesive residue remains on the face side of the thinned-down wafer after separation
Solution Approach 1:
The adhesive is segmented into two functional regions: the first adhesive region in the outer circumferential area that is removed during separation, and the second adhesive region in the central device area that remains to prevent residue on the device surface. This segmentation ensures that adhesive removal occurs only where needed while preserving adhesive in the device region.
Solution Approach 2:
The adhesive in the first outer circumferential region is selectively removed or reduced through UV exposure and mechanical removal processes, extracting only the adhesive portion needed for separation while leaving the second adhesive region intact to protect the device area from residue.
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 method effectively separates the device wafer from the support plate without adhesive residue, reducing material constraints and enhancing handling of thin wafers.
Implementation Method 1
affixing the face of the support plate and the face side of the device wafer to each other with use of at least the resin
Implementation Method 2
it would make it possible to use another process called a laser debonding process that reduces the bonding strength of the adhesive by irradiating the adhesive with a laser beam in an ultraviolet wavelength band
Implementation Method 3
thinning down the device wafer by grinding or polishing or by grinding and polishing a reverse side of the device wafer
Implementation Method 4
thinning down the device wafer by grinding or polishing or by grinding and polishing a reverse side of the device wafer
Data Source
AI summary
A processing method includes forming a recess circumferentially along a support plate including a face having a size equal to or larger than the diameter of a device region and supporting a device wafer, in an outer circumferential region of the face that is positioned outwardly of a central region thereof that is commensurate with the device region, affixing the face of the support plate and the face side of the device wafer to each other with use of at least resin supplied to the recess, thinning down the device wafer by grinding or polishing or by grinding and polishing a reverse side of the device wafer, removing a region of the resin circumferentially along the device wafer, thereby to reduce a bonding force between the device wafer and the support plate, and separating a portion of the device wafer that includes the device region from the support plate.