Die Attach Adhesive Composition for Void-Free Thin Die Bonding
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Solution Overview
Problem
Conventional adhesive compositions for semiconductor packaging face challenges in achieving precise bond line thickness (BLT), minimizing fillets, and preventing voids and tilt in thin die applications, leading to delamination, cracking, and increased material costs.
Innovation Solution
A curable adhesive composition comprising a thermosetting or thermoplastic resin, low melting point metal or alloy particles, and high melting point metal or alloy particles, along with an optional curing agent, to ensure precise BLT, minimal fillets, and void-free bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional die attach paste is used with thin semiconductor dies, then bonding is achieved, but void formation occurs during curing leading to poor adhesion
Solution Approach 1:
The patent modifies the adhesive composition parameters by incorporating specific filler materials (metal particles, ceramic particles, or glass beads) with controlled size distributions and adding volatile solvents that evaporate during curing. This parameter change transforms the adhesive from a simple bonding agent to a composite material that actively manages void formation through controlled solvent evaporation and particle packing, thereby improving adhesion reliability while eliminating the harmful void effect
Solution Approach 2:
The patent creates a composite adhesive composition combining organic polymer resin with inorganic fillers (metal particles, ceramic particles, or glass beads) and volatile solvents. This composite structure allows the different components to work synergistically: the polymer provides bonding, the fillers provide structural support and control flow, and the volatile solvent enables void elimination through evaporation, collectively solving the void formation problem while maintaining strong adhesion
2Manufacturing precision
If bond line thickness is reduced to minimize fillet, then material usage is optimized, but delamination occurs due to insufficient bonding strength
Solution Approach 1:
The patent optimizes the adhesive composition parameters including polymer resin type, filler particle size distribution, and volatile solvent content to achieve optimal rheological properties. These parameter changes enable the adhesive to maintain adequate bonding strength at reduced bond line thickness by improving wetting characteristics and controlling viscosity, thus achieving precise thickness control without sacrificing bonding strength
Solution Approach 2:
The patent creates local quality variations within the adhesive composition through controlled particle size distribution and spatial arrangement of fillers. The combination of different particle sizes creates a hierarchical structure that provides both flowability for thin bond lines and structural integrity for bonding strength, allowing the adhesive to perform differently at different scales - flowing easily at application but maintaining strength at the final thin bond line
3Reliability
If pressure is applied to ensure proper bonding, then adhesion is improved, but thin semiconductor dies crack or tilt
Solution Approach 1:
The patent introduces a volatile solvent as an intermediary that facilitates bonding without requiring high pressure. The solvent evaporates during curing, creating capillary forces and vapor pressure that drive adhesive flow and bonding autonomously, acting as a mediator between the adhesive and die surfaces. This intermediary mechanism enables strong adhesion while eliminating the need for high pressure that would damage thin dies
Solution Approach 2:
The patent replaces the mechanical pressure system with a chemical-physical system involving volatile solvent evaporation. Instead of applying external mechanical force to achieve bonding, the system uses the phase change of the volatile solvent (liquid to vapor) to generate internal pressure and capillary forces that drive adhesive flow and bonding, substituting a mechanical process with a thermal-chemical process that is gentler on thin dies
4Productivity
If adhesive composition is cured quickly, then productivity is improved, but voids form due to incomplete solvent volatilization
Solution Approach 1:
The patent selects volatile solvents with specific evaporation rates and boiling points that are optimized for the curing process. By changing the parameter of solvent volatility, the system enables rapid evaporation that keeps pace with the curing speed, allowing fast curing without void formation. The solvent parameters are specifically chosen to evaporate completely within the curing timeframe, simultaneously achieving high productivity and defect-free quality
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 achieves excellent BLT control, eliminates voids, and reduces tilt trends, facilitating reliable bonding of thin dies with improved adhesion strength and suitability for industrial production.
Implementation Method 1
a plurality of particles of a first metal or alloy having a melting point no higher than 300° C.
Implementation Method 2
a thermosetting or thermoplastic resin component
Data Source
AI summary
This invention relates to a curable adhesive composition. In particular, the present invention relates to a curable adhesive composition for die attach, which eliminates the void issue, minimizes the fillet, and has lower bond line thickness and tilt trend, when cured.