Thermocompression Bonding Head for Thin IC Warpage Control
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Solution Overview
Problem
The challenge in mounting electronic components on wiring boards is the deterioration of connection reliability due to insufficient heat application during thermocompression bonding, especially for thin components, which can lead to warpage and void generation, and existing solutions using elastic heads with specific rubber hardness ranges do not adequately address these issues for components thinner than 200 μm.
Innovation Solution
A method and apparatus utilizing a non-conductive adhesive agent with low minimum melt viscosity and an elastic thermocompression bonding head with rubber hardness less than or equal to 60 to perform thermocompression bonding, ensuring uniform pressure and reducing warpage by maintaining the binding resin on the component's surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a hard head made of metal or ceramics is used for thermocompression bonding, then the electronic component can be mounted, but sufficient heat cannot be applied to the fillet portion of the adhesive agent, causing deterioration of connection reliability
Solution Approach 1:
The patent changes the material parameter of the bonding head from hard materials (metal or ceramics) to elastic materials (silicone rubber), specifically selecting rubber hardness between 40 and 80. This parameter change allows the bonding head to deform and conform to the component shape, enabling sufficient heat application to the fillet portion while maintaining connection reliability.
2Stress or pressure
If an elastic head made of elastomer with rubber hardness below 40 is used, then pressure can be applied uniformly, but the initial resistance of the adhesive agent deteriorates
Solution Approach 1:
The patent establishes a specific parameter range for rubber hardness (40-80) that balances two competing requirements: sufficient elasticity to apply uniform pressure and sufficient rigidity to maintain initial resistance of the adhesive agent. This parameter optimization resolves the contradiction between pressure uniformity and adhesive performance.
3Stress or pressure
If an elastic head made of elastomer with rubber hardness greater than or equal to 80 is used, then pressure can be applied, but voids are generated in the binding resin of the adhesive agent
Solution Approach 1:
The patent identifies that rubber hardness >= 80 causes insufficient deformation to apply adequate pressure to eliminate voids. By setting the upper limit of rubber hardness at 80, the bonding head achieves sufficient elasticity to conform to the component and apply uniform pressure that prevents void formation in the binding resin.
4Ease of manufacture
If a non-conductive adhesive film with low melt viscosity is used, then the electronic component can be mounted, but significant warpage occurs in thin electronic components
Solution Approach 1:
The patent addresses warpage in thin components by optimizing the rubber hardness parameter of the bonding head. The elastic deformation capability enabled by rubber hardness <= 80 allows for more uniform pressure distribution during bonding, which reduces differential thermal expansion and minimizes warpage in thin electronic components with thickness <= 200 μm.
5Length of moving object
If the electronic component thickness is reduced to <= 200 μm to achieve smaller devices, then device size is reduced, but warpage significantly increases during thermocompression bonding
Solution Approach 1:
The patent specifically addresses the warpage problem in thin components (thickness <= 200 μm) by optimizing the bonding head's rubber hardness to 80 or less. This parameter change enables the bonding head to deform and apply uniform pressure across the thin component surface, compensating for the reduced stiffness of thin components and minimizing warpage during thermocompression bonding.
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 significantly reduces warpage and enhances connection reliability by ensuring the binding resin stays on the component's surface, preventing void generation and improving mounting efficiency for thin electronic components.
Implementation Method 1
a fat elastic head made of an elastic body such as silicone rubber
Implementation Method 2
thermocompression bonding technique
Data Source
AI summary
An electronic component mounting apparatus is capable of significantly reducing a warpage amount of an electronic component warped in a case of thermocompression bonding using a non-conductive adhesive agent having a low minimum melt viscosity and having no conductive particle where a thin electronic component having a thickness smaller than or equal to 200 μm is mounted on a wiring board. In the mounting apparatus, a non-conductive adhesive film having the minimum melt viscosity lower than or equal to 1.0×103 Pa·s is placed on a wiring board placed on a base, and an IC chip having a thickness smaller than or equal to 200 μm is placed on the non-conductive adhesive film. In the mounting apparatus, the IC chip is pressurized by a thermocompression bonding head having a compression bonding portion made of elastomer having a rubber hardness lower than or equal to 60, so that the IC chip is bonded onto the wiring board by thermocompression.