Two-Exothermic-Peak Adhesive for Semiconductor Voids
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Solution Overview
Problem
In semiconductor packaging, existing adhesive compositions face challenges in achieving high fluidity for wire bonding while minimizing void formation and eliminating semi-curing processes, which can lead to defects and reduced reliability due to uneven adherends and voids generated during the curing and epoxy molding processes.
Innovation Solution
An adhesive composition with two exothermic peaks between 65° C. and 350° C., comprising a thermoplastic resin, epoxy resin, phenolic curing agent, amine curing agent, and a curing accelerator, which allows for reduced void formation and omission of the semi-curing process, providing compressive strength and reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-curing adhesive composition is used, then the manufacturing process is simple, but voids are generated during molding and reliability is poor
Solution Approach 1:
The adhesive composition is segmented into multiple curing stages with distinct exothermic peaks at different temperature ranges. The first exothermic peak occurs at 65-185°C and the second at 155-350°C, allowing progressive curing that eliminates voids while maintaining process simplicity. This segmentation of the curing process into temperature-dependent stages resolves the contradiction between manufacturing simplicity and bonding reliability.
2Ease of operation
If high-fluidity adhesive is used for wire bonding, then wire bonding is facilitated, but voids are generated during molding
Solution Approach 1:
The adhesive composition's physical and chemical parameters are dynamically changed through temperature-dependent curing stages. At lower temperatures (first exothermic peak), the adhesive maintains high fluidity for wire bonding operations. As temperature increases to the second exothermic peak range, the adhesive progressively cures, increasing viscosity and eliminating voids during molding. This parameter transformation resolves the contradiction between operational ease and void prevention.
3Manufacturing precision
If semi-curing process is implemented to reduce voids, then molding quality improves, but productivity decreases
Solution Approach 1:
The patent merges the semi-curing process with the final molding process by designing an adhesive composition that undergoes progressive curing during the molding operation itself. The two-exothermic-peak composition allows the adhesive to continue curing at elevated molding temperatures, combining what were previously separate operations. This integration maintains high molding quality while eliminating the dedicated semi-curing step, thereby improving productivity.
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 adhesive composition effectively eliminates voids and enhances the reliability of semiconductor devices by providing sufficient compressive strength and fluidity for wire bonding, improving processability and reducing defects in multi-chip packaging.
Implementation Method 1
the adhesive composition having two exothermic peaks between 65° C. and 350° C.
Data Source
AI summary
An adhesive composition for a semiconductor has two exothermic peaks between 65° C. and 350° C. and has an area ratio of voids of less than 10%, measured after curing at 150° C. for 10 minutes and then at 150° C. for 30 minutes, and then molding at 175° C. for 60 seconds. A first exothermic peak appears between 65° C. and 185° C. and a second exothermic peak appears between 155° C. and 350° C.