Injection Mold Base Plate Venting for Packaged Chip Reliability
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Solution Overview
Problem
The existing injection moulding processes for packaged chips face challenges in exhausting air, leading to unreliable package structures due to gas residue, especially when the gas hole in the substrate is blocked during the moulding process.
Innovation Solution
The injection mould features a base plate with a mesh-type gas duct structure that connects in multiple directions, allowing gas to be exhausted even if two ends of the ducts are blocked, enhancing the reliability of the moulded packaged chip by ensuring effective air removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gas hole is arranged in the substrate for gas exhaust, then the structure is simple, but the gas exhaust reliability is low when the gas hole is blocked
Solution Approach 1:
The single gas hole is segmented into multiple gas holes arranged in an array on the substrate. Each gas hole connects to the base plate, creating multiple independent exhaust pathways. This segmentation ensures that if one gas hole is blocked, others remain functional, significantly improving gas exhaust reliability without requiring a complex duct system.
Solution Approach 2:
The gas exhaust system transitions from a single-point exhaust to a distributed array of exhaust points on the substrate surface. This dimensional change from one-dimensional single pathway to two-dimensional array provides redundant exhaust routes, ensuring reliable gas removal even when individual pathways are blocked.
2Volume of moving object
If the gap between chip and substrate is small with direct solder bump connection, then the package structure is compact, but air is difficult to be exhausted during filling
Solution Approach 1:
The compact package volume is maintained while segmenting the gas exhaust function into multiple small gas holes distributed across the substrate. This segmentation allows effective gas removal from the small gap between chip and substrate without increasing overall package volume, as each small hole provides a direct exhaust pathway from the confined space.
Solution Approach 2:
Multiple gas holes are strategically positioned at different locations where gas accumulation is most likely to occur in the chip-substrate gap. This local quality approach ensures that gas can be exhausted from various regions of the compact package simultaneously, maintaining effective exhaust efficiency despite the small overall volume.
3Reliability
If a mesh-type gas duct structure is implemented in the base plate, then gas exhaust reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The mesh-type gas duct structure segments the exhaust function into multiple directional pathways within the base plate. This segmentation provides redundant exhaust routes that improve reliability, while the modular nature of the mesh pattern allows for standardized manufacturing processes, reducing the impact of increased structural complexity on manufacturing ease.
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 solution improves the reliability of the packaged chip by ensuring effective gas exhaust during injection moulding, reducing the risk of air residue and enhancing the structural integrity of the chip package.
Implementation Method 1
The base plate has a mesh-type gas duct structure formed therein, and the gas ducts extending in various directions connect to one another
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An injection mould and an injection moulding method are provided. The injection mould includes a base plate used to place a packaged chip to be injection moulded including a substrate and at least one of the chips fixed on the front substrate by a flip chip process. The substrate has a gas hole. Two or more gas ducts that extend in at least two intersected directions and connect with one another are formed in the base plate. Two ends of each one of gas ducts are open, and at least one of the gas ducts is buried into the base plate. Each one of gas ducts is provided with a gas outlet. When the packaged chip is placed on the base plate, the gas outlet connects with the gas hole of the substrate. The injection mould is favorable for exhausting gas in a cavity of the injection mould during injection moulding to improve the reliability of the moulded packaged chip.