Package Substrate Long-Strip Venting for Mold Compound Filling
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Solution Overview
Problem
Existing package substrates face challenges in achieving effective mold compound filling during injection molding, particularly on non-square chip dimensions, due to issues with air venting and blockages caused by impurities, leading to unreliable package structures and poor filling effects.
Innovation Solution
The use of long-strip vent holes extending through the substrate surfaces, strategically positioned and shaped to align with the chip's dimensions, enhances gas venting and reduces blockages by providing a larger aperture area and symmetrical distribution, improving the flow of mold compound and reducing the risk of impurities getting stuck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single vent hole is provided on the package substrate, then gas venting is facilitated in the direction of the short side of the chip, but in the direction of the long side of the chip the venting effect is insufficient and air holes remain
Solution Approach 1:
The single vent hole is segmented into multiple vent holes arranged in an array. This segmentation allows gas to escape from multiple locations simultaneously, improving venting effectiveness in both the short side and long side directions of the chip, thereby resolving the directional coverage limitation of a single vent hole
Solution Approach 2:
Multiple vent holes are combined to form a coordinated venting system. The vent holes work together to provide comprehensive gas escape pathways across the entire chip area, merging individual venting capabilities into a unified solution that addresses both directional venting requirements
2Reliability
If multiple air holes are provided to improve venting in the long side direction, then venting coverage is enhanced, but the mold compound filling effect deteriorates due to increased complexity and potential blockages
Solution Approach 1:
The vent holes are designed with specific local characteristics including optimized diameter, spacing, and arrangement patterns. This local quality optimization ensures that each vent hole contributes effectively to gas escape while minimizing interference with mold compound flow, thereby maintaining good filling effect even with multiple vent holes
Solution Approach 2:
The vent holes are positioned within the projection area of the chip on the substrate, using only the necessary portion of the substrate area for venting purposes. This partial action approach provides sufficient venting coverage without excessively complicating the overall structure or creating unnecessary blockage points that would harm filling effect
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 configuration enhances the filling effect of the mold compound, reduces air bubbles, and increases the reliability of the package structure by ensuring efficient gas venting and preventing vent hole blockages, while maintaining a concentrated soldering region and minimizing design area waste.
Implementation Method 1
at least one vent hole extending through the first surface and the second surface of the substrate, the vent hole comprising at least a long-strip hole
Implementation Method 2
as the mold compound is filled, gas is vented from the air holes on the substrate during injection molding, thereby increasing the filling effect of the mold compound fluid
Data Source
AI summary
The present disclosure relates to a package substrate comprising: a substrate having opposing first surface and second surface; at least one vent hole extending through the first surface and the second surface of the substrate, the vent hole comprising at least a long-strip hole.