Underfill Void Elimination via Vacuum Heating
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Solution Overview
Problem
Existing methods for fabricating semiconductor devices with underfill materials between circuit boards and semiconductor chips often result in voids that are difficult to eliminate efficiently and quickly.
Innovation Solution
A method and equipment for filling underfill material between a semiconductor chip and a circuit board, involving pre-heating, coating, and heating the underfill material in a vacuum state to reduce viscosity and eliminate voids, using a sequence of chucks and transfer units within underfill equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to fill underfill material, then the underfill material can be placed between the circuit board and semiconductor chip, but voids form within the underfill material that are difficult to eliminate
Solution Approach 1:
The patent applies vacuum environment (inert atmosphere principle) to remove voids from underfill material. The vacuum pump creates a vacuum state that draws air and voids out of the underfill material through vacuum holes in the chuck, eliminating harmful voids while maintaining the underfill material in place.
Solution Approach 2:
The patent changes physical parameters by applying vacuum pressure and heating to the underfill material. The vacuum pressure parameter removes voids, while the temperature parameter (heating to 80-150°C) reduces viscosity and facilitates void removal, transforming the underfill material's state to eliminate defects.
2Reliability
If time is taken to eliminate voids in underfill material, then voids can be removed, but the process takes too long
Solution Approach 1:
The patent uses heating (80-150°C) to change the viscosity parameter of the underfill material, making it more fluid and easier to degas. This parameter change accelerates void removal significantly, reducing the time required compared to cooling methods while maintaining effective void elimination.
Solution Approach 2:
The patent combines vacuum application and heating simultaneously in a continuous process. The vacuum pump operates continuously while heating occurs, creating a synergistic effect that removes voids rapidly without interruption, eliminating the need for separate processing steps.
3Reliability
If heating is applied to reduce viscosity for void removal, then voids can be eliminated more effectively, but energy consumption increases
Solution Approach 1:
The patent optimizes the temperature parameter to a moderate range (80-150°C) that is sufficient to reduce underfill viscosity for effective void removal but not excessively high. This balanced parameter selection achieves the desired effect while minimizing energy consumption compared to higher temperature methods.
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 effectively eliminates or reduces voids in the underfill material in a short time, enhancing the quality and reliability of semiconductor device fabrication.
Implementation Method 1
a vacuum pump (530) connected to the post-treatment cover (520) to maintain the inside of the post-treatment cover (520) in a vacuum state
Implementation Method 2
heating the underfill material (UM) of the circuit board (P) placed on the post-treatment chuck (510)
Data Source
AI summary
A method of fabricating a semiconductor device comprises loading a circuit board including a semiconductor chip into underfill equipment, positioning the circuit board on a depositing chuck of the underfill equipment, filling an underfill material in a space between the semiconductor chip and the circuit board placed on the depositing chuck; transferring the circuit board including the underfill material so that it is positioned on a post-treatment chuck of the underfill equipment; heating the underfill material of the circuit board placed on the post-treatment chuck in a vacuum state, and unloading the circuit board, of which the underfill material has been heated in the vacuum state, from the underfill equipment.