Semiconductor Underfill Corner Opening Design
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Solution Overview
Problem
In semiconductor devices with flip-chip bonding, the staggered arrangement of pads and bonding leads leads to insufficient wettability and spread of underfill material, causing exposure of lead wires and potentially degrading the reliability of the semiconductor device.
Innovation Solution
The semiconductor device design includes a substrate with a staggered arrangement of bonding leads and an insulating film with specific opening portions, where the second opening portion on the air vent side is made closer to the semiconductor chip to improve underfill material wettability and reduce lead exposure, and a manufacturing method that involves filling the gap between the substrate and chip with underfill material through a strategically positioned opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bonding leads are arranged in a staggered manner with small pitch to increase the number of pads on the semiconductor chip, then the number of pads can be increased, but the wettability and spread of underfill material becomes insufficient, causing lead wire exposure and potential reliability degradation
Solution Approach 1:
The patent applies local quality by creating a localized opening portion at the corner of the insulating film where underfill material is injected. This local structural modification provides a specific region with enhanced wettability and underfill material accumulation, while the rest of the bonding leads maintain their staggered arrangement for high pad density. The opening portion serves as a dedicated zone for improving underfill material spread without altering the overall staggered configuration.
2Area of stationary object
If bonding leads are arranged in a staggered manner with small pitch, then space utilization is improved, but it becomes difficult to provide lead wires between adjacent bonding leads, requiring cantilever lead form which complicates the structure
Solution Approach 1:
The patent segments the opening of the insulating film into multiple portions, with at least one opening portion located at a corner. This segmentation allows lead wires to be routed through specific opening portions, separating the lead wire path from the bonding lead arrangement. The staggered bonding leads maintain their compact configuration while lead wires can be independently positioned through the segmented openings, reducing structural complexity.
3Ease of operation
If the opening portion of the insulating film is widely opened to accommodate lead wires, then lead wire routing is facilitated, but the wettability and spread of underfill material at the corner is degraded
Solution Approach 1:
The patent creates a localized opening portion at the corner of the insulating film that is specifically optimized for underfill material injection and wettability. This local opening is positioned and sized to maximize underfill material spread while maintaining adequate space for lead wire routing. The opening portion serves as a dedicated functional zone that simultaneously addresses both lead wire accessibility and underfill material wettability without requiring the entire insulating film opening to be enlarged.
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 design enhances the wettability and spread of underfill material, reducing lead exposure and improving the reliability of the semiconductor device by ensuring better filling and bonding between the substrate and chip.
Implementation Method 1
the corner of the second opening portion 7i is made close to the semiconductor chip 1, thereby improving the wettability and spread of the underfill material 4 at the second opening portion 7i
Data Source
AI summary
To provide a semiconductor device with improved reliability. The semiconductor device includes a wiring board, a microcomputer chip flip-chip bonded over the wiring board via gold bumps, a first memory chip laminated over the microcomputer chip, wires for coupling the first memory chip to the wiring board, an underfill material with which a flip-chip coupling portion of the microcomputer chip is filled, and a sealing member for sealing the microcomputer chip and the first memory chip with resin. Further, the corner of a second opening portion of a solder resist film of the wiring board corresponding to the corner of the chip on the air vent side in charging the underfill material is made close to the microcomputer chip, which can improve the wettability and spread of the underfill material at the second opening portion, thus reducing the exposure of leads to the second opening portion, thereby improving the reliability of the semiconductor device.