Temporary Wafer Bonding Composition for Copper Surface Debonding
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Solution Overview
Problem
Conventional temporary bonding adhesives for semiconductor wafers face challenges with copper surfaces, requiring plasma treatment and high-temperature curing for debonding, which complicates the process and can damage the wafer.
Innovation Solution
A temporary bonding composition comprising a curable adhesive material, a release additive, and a copper passivation agent is used, which allows for low-force mechanical debonding from copper surfaces without the need for plasma treatment, by phase-separating the release additive towards the active surface of the semiconductor wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional temporary bonding adhesives are used on copper surfaces, then bonding strength is achieved, but plasma treatment and high-temperature curing are required which complicates the process and can damage the wafer
Solution Approach 1:
A copper passivation agent is introduced as an intermediary substance between the adhesive and the copper surface. This passivation agent modifies the copper surface properties to enable direct bonding with conventional adhesives without requiring plasma treatment or high-temperature curing, thus reducing process complexity while maintaining bonding strength
Solution Approach 2:
The copper surface is pre-treated with a passivation agent before adhesive application. This preliminary action prepares the surface in advance to be compatible with the adhesive, eliminating the need for subsequent plasma treatment or high-temperature curing steps
2Strength
If crosslinking adhesives are used for temporary bonding, then bulk strength is achieved, but they remain on both surfaces after separation requiring additional cleaning or etching steps
Solution Approach 1:
The adhesive formulation is designed with different functional components: a crosslinking adhesive providing bulk strength and a release additive concentrated at the adhesive-wafer interface. This local differentiation allows the bulk to maintain strength while the interface enables easy release, eliminating the need for additional cleaning steps
Solution Approach 2:
The temporary bonding composition is a composite material combining a crosslinking adhesive with a release additive. The crosslinking adhesive provides structural integrity and bulk strength, while the release additive ensures easy separation from the wafer surface, achieving both strength and ease of manufacture
3Ease of manufacture
If thermoplastic adhesives are used for temporary bonding, then residual adhesive can be easily removed by solvent cleaning, but they become soft when heated which limits their use in certain applications
Solution Approach 1:
The adhesive's thermal properties are modified by adding a crosslinking component that raises the glass transition temperature and provides thermal stability. Simultaneously, a release additive is incorporated to maintain ease of removal, thus changing the material parameters to satisfy both cleaning ease and thermal stability requirements
4Ease of operation
If room temperature softness is provided in crosslinking adhesives for easy peeling, then debonding is facilitated, but it provides challenges in achieving uniform wafer thicknesses after grinding
Solution Approach 1:
The adhesive system exhibits different mechanical properties at different locations and conditions: it is soft at the adhesive-wafer interface at room temperature to facilitate easy peeling, but maintains sufficient rigidity in the bulk to support uniform wafer handling and grinding, achieving both ease of operation and manufacturing precision
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 solution enables efficient and damage-free debonding of semiconductor substrates from carriers with copper surfaces, reducing the risk of deformation and residual adhesive, and simplifying the processing steps.
Implementation Method 1
Upon curing of the adhesive material, the release additive phase-separates toward the active surface of the semiconductor wafer
Implementation Method 2
a copper passivation agent that coats the copper surface to provide release
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 2D~2F
AI summary
Compositions containing an adhesive material, a release additive and a copper passivation agent are suitable for temporarily bonding two surfaces, such as a semiconductor substrate active side and a carrier substrate. These compositions are useful in the manufacture of electronic devices where a temporary bonding of a component to a substrate having a copper surface is desired.