Temporary Wafer Bonding Composition to Minimize Spin-Coating Bubbles
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Solution Overview
Problem
Conventional temporary bonding agents for wafers in electronic device production suffer from air bubble entrapment during spin coating, which adversely affects physical properties and requires improved compositions to minimize air bubbles.
Innovation Solution
A composition comprising monofunctional (meth)acrylate with specific surface tension, polyfunctional (meth)acrylate with high viscosity or solid state at room temperature, and a photo radical polymerization initiator, with a viscosity range of 500 to 10,000 mPa·s, to reduce air bubble formation and ensure flatness during spin coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional temporary bonding agent is applied by spin coating, then the wafer can be bonded to the support, but air bubbles are entrapped in the bonding agent which adversely affect physical properties
Solution Approach 1:
The patent changes the physical parameters of the bonding agent by controlling the molecular weight and viscosity of the polyisobutene polymer, and adjusting the ratio of monofunctional to polyfunctional (meth)acrylate components. These parameter changes optimize the fluid dynamics during spin coating to prevent air bubble entrapment while maintaining bonding reliability.
Solution Approach 2:
The patent creates a composite bonding agent system combining polyisobutene polymer with a specific ratio of monofunctional (meth)acrylate and polyfunctional (meth)acrylate. This composite formulation synergistically provides both the viscosity control needed to prevent air bubbles and the adhesive properties required for reliable bonding.
2Manufacturing precision
If the temporary bonding agent has low viscosity for easy spin coating, then uniform film formation is improved, but air bubble entrapment increases
Solution Approach 1:
The patent optimizes the viscosity parameter to a specific range (500-5000 cP at 23°C) by controlling the molecular weight of polyisobutene (50,000-2,000,000) and the ratio of acrylic components. This parameter optimization achieves the balance between film uniformity and air bubble prevention.
3Ease of operation
If the temporary bonding agent uses organic resin film for flexibility, then ease of application is improved, but strength and heat resistance are insufficient for high temperature steps
Solution Approach 1:
The patent develops a composite adhesive composition combining polyisobutene polymer with (meth)acrylate monomers and oligomers. This composite material provides both the flexibility needed for easy application and the thermal stability required for high-temperature processing, overcoming the limitations of conventional organic resin films.
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating polyisobutene with specific molecular weight ranges and controlling the ratio of monofunctional to polyfunctional (meth)acrylate components. These compositional changes enhance the heat resistance while maintaining the operational ease of the bonding agent.
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 composition effectively minimizes air bubble entrapment, ensuring flatness and suitability for subsequent processing steps, with excellent heat resistance and releasability, suitable for high-temperature applications in electronic device manufacturing.
Implementation Method 1
a photo radical polymerization initiator, with a viscosity ranging from 500 to 10,000 mPa·s at atmospheric pressure at 23° C. and a shear rate at 1 s−1 as measured by a rotatory rheometer
Implementation Method 2
a viscosity ranging from 500 to 10,000 mPa·s at atmospheric pressure at 23° C. and a shear rate at 1 s−1 as measured by a rotatory rheometer
Data Source
AI summary
A composition for temporary bonding, comprising the following (A) to (C), and having a viscosity ranging from 500 to 10,000 mPa·s at atmospheric pressure at 23° C. and a shear rate at 1 s−1 as measured by a rotatory rheometer:(A) a monofunctional (meth)acrylate having a surface tension ranging from 20 to 30 mN/m as measured by ds/de method of pendant drop method at 23° C.;(B) a polyfunctional (meth)acrylate, which has a viscosity of 1,000 mPa·s or more at atmospheric pressure at 23° C. and a shear rate at 1 s−1 as measured by a rotatory rheometer, is solid at 23° C., or has a molecular weight of 500 or more and a viscosity of 100 mPa·s or more and less than 1,000 mPa·s at atmospheric pressure at 23° C. and a shear rate at 1 s−1 as measured by a rotatory rheometer; and(C) a photo radical polymerization initiator.