Thermally Curable Wafer Bonding Composition for Room Temperature Debonding
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Solution Overview
Problem
Current methods for temporarily bonding wafers in semiconductor device fabrication lack thermal, mechanical, and chemical stability, and require expensive equipment or complex processes, making them unsuitable for high-temperature operations and cost-effective production.
Innovation Solution
A method involving the formation of a bi-layer film with a thermally stable cross-linkable polymer and a crosslinking agent, allowing for bonding at a lower temperature and subsequent crosslinking, enabling debonding at room temperature with mechanical force, without the need for special equipment or solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional temporary bonding compositions are used, then wafer bonding is achieved, but the bonded structure lacks thermal stability for high-temperature fabrication operations
Solution Approach 1:
The patent applies parameter changes by utilizing the temperature-dependent properties of silicone adhesives. The adhesive is formulated to remain soft and debondable at room temperature (below its glass transition temperature) while becoming thermally stable and mechanically strong at elevated temperatures (above its glass transition temperature) during fabrication operations, thus resolving the contradiction between thermal stability and bonding reliability.
Solution Approach 2:
The patent employs composite materials by combining silicone adhesive with specific additives including glass fiber reinforcement, metal particle fillers, and coupling agents. This composite formulation enhances the adhesive's thermal stability and mechanical strength at fabrication temperatures while maintaining room-temperature debondability, thereby achieving both thermal stability and bonding reliability.
2Ease of operation
If glass carrier wafers are used with special laser release, then adhesive release is achieved, but fabrication cost increases significantly
Solution Approach 1:
The patent replaces the complex optical system (special laser equipment) with a simple mechanical solution. By formulating the adhesive to naturally debond at room temperature through mechanical force application, the invention eliminates the need for expensive laser release equipment and glass carrier wafers, significantly reducing fabrication costs while maintaining ease of adhesive release.
Solution Approach 2:
The patent employs inexpensive organic adhesive compositions that can be easily applied and removed, replacing expensive reusable glass carrier wafers. The adhesive serves its temporary bonding function during fabrication and is then completely removed without requiring special release equipment, reducing overall fabrication costs while maintaining operational simplicity.
3Ease of manufacture
If room temperature debonding with mechanical force is implemented, then fabrication cost is reduced, but the bonded structure must maintain thermal stability during processing
Solution Approach 1:
The patent utilizes parameter changes by exploiting the glass transition temperature of silicone adhesives. The adhesive composition is designed to exhibit fundamentally different mechanical properties at different temperatures: soft and mechanically removable at room temperature, but rigid and thermally stable during high-temperature fabrication processing, thus achieving both cost-effective debonding and structural stability.
Solution Approach 2:
The patent applies dynamics by creating a temperature-responsive adhesive system that dynamically changes its mechanical properties based on processing conditions. The adhesive transitions from a rigid, stable state during high-temperature processing to a soft, debondable state at room temperature, enabling the bonded structure to maintain stability when needed and be easily separated when fabrication is complete.
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 approach provides a cost-effective, efficient, and stable bonding method for semiconductor devices, allowing for elevated temperature processing while enabling easy debonding without residue, using a simpler process compared to existing methods.
Implementation Method 1
a first polymer layer over a surface of a first substrate where the polymer layer comprises a thermally stable and crosslinkable polymer
Implementation Method 2
capable of debonding the wafers at room temperature using a mechanical force
Data Source
AI summary
Embodiments in accordance with the present invention are directed to a method of fabricating a semiconductor device wherein a device wafer substrate is coated with a composition encompassing a surface energy modifier and a thermally stable polymer which is then bonded to a carrier wafer substrate coated with a composition encompassing a crosslinkable polymer composition. The polymer composition allows thinning of a device wafer before separating from the carrier wafer at room temperature.