Electronic Component Adhesive Void Suppression and Wicking Control
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Solution Overview
Problem
Existing methods for semiconductor chip mounting, such as flip chip mounting, face challenges in preventing the occurrence of voids and adhesive wicking up to the upper surface of the chip, leading to contamination and alignment issues.
Innovation Solution
A curable adhesive comprising a curable compound, a curing agent, and an inorganic filler, with specific viscosity and thixotropic properties, is applied to the substrate before bonding, ensuring the adhesive wets and spreads to eliminate air bubbles and prevent wicking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sealing resin is injected into a narrow gap between semiconductor chips or between the chip and substrate, then the gap can be filled, but air is easily contained resulting in occurrence of voids
Solution Approach 1:
The patent applies sealing resin in advance to the bonding area before electrode bonding, rather than injecting it after bonding. This preliminary application allows the resin to be positioned correctly before the chip is mounted, preventing air entrapment during the bonding process and eliminating void formation while ensuring complete gap filling.
Solution Approach 2:
The patent specifies precise viscosity parameters for the sealing resin (100 Pa·s or less) and controls thixotropic properties (thixotropic index of 1.1 or less). These parameter changes ensure the resin has appropriate flow characteristics to fill narrow gaps completely while preventing air bubble entrapment during application and bonding.
2Reliability
If a sealing resin is applied in advance in a bonding area, then void occurrence can be reduced, but the resin easily wicks up to the upper surface of the semiconductor chip causing contamination
Solution Approach 1:
The patent precisely controls the viscosity parameter of the sealing resin (100 Pa·s or less) and its thixotropic properties (thixotropic index of 1.1 or less). These parameter changes create a resin that flows sufficiently to fill gaps and prevent voids, yet maintains enough viscosity to resist capillary wicking up to the chip surface, thereby preventing contamination while ensuring void suppression.
Solution Approach 2:
The patent references and builds upon the underfill composition technology described in Patent Literature 2, adapting it for sealing applications. By copying the successful formulation approach using surface-treated nanoparticles and controlling rheological properties, the patent achieves both void suppression and wicking prevention in the sealing resin.
3Productivity
If the viscosity of sealing material is low (100 Pa·s or less), then the material can be injected quickly into narrow gaps, but air bubbles are produced during injection
Solution Approach 1:
The patent optimizes the viscosity parameter to 100 Pa·s or less while simultaneously controlling the thixotropic index to 1.1 or less. This dual parameter optimization allows the resin to flow quickly into narrow gaps at low shear rates (maintaining low viscosity for fast injection) while preventing air bubble entrapment through controlled thixotropic behavior that stabilizes the resin structure during the injection process.
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 effectively suppresses void formation and prevents wicking to the chip surface, enhancing the reliability and application properties of the semiconductor chip mount.
Implementation Method 1
the adhesive for electronic components wets and spreads, and squeezes out air bubbles
Implementation Method 2
a viscosity at 5 rpm measured at 25° C. using an E type viscometer is A1 (Pa·s) and a viscosity at 0.5 rpm measured at 25° C. using an E type viscometer is A2 (Pa·s), the range including values on the solid lines but not including values on the dashed line
Data Source
AI summary
An adhesive for electronic components, including a curable compound, a curing agent, and an inorganic filler, wherein A1 and A2/A1 fall within a range surrounded by solid lines and a dashed line in Fig. 1A wherein a viscosity at 5 rpm measured at 25° C. using an E type viscometer is A1 (Pa·s) and a viscosity at 0.5 rpm measured at 25° C. using an E type viscometer is A2 (Pa·s), the range including values on the solid lines but not including values on the dashed line, and a blending amount of the curing agent is 5 to 150 parts by weight and a blending amount of the inorganic filler is 60 to 400 parts by weight based on 100 parts by weight of the curable compound.