Semiconductor Package Spacer Groove for DAF Overflow Control
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Solution Overview
Problem
In semiconductor packages, the fluidity of die attach films (DAF) due to high pressure and temperature during the die attach process can cause the adhesive to flow onto exposed spacer chips, leading to reliability issues and process defects by penetrating onto the upper surface of overlying semiconductor chips.
Innovation Solution
The use of spacer chips with a groove on their upper surface, where the adhesive film can fill the groove, preventing it from overflowing onto the semiconductor chips, is implemented. This design includes a package substrate with spacer chips spaced apart and a sealing member to cover the chips, ensuring the adhesive fills the groove and maintains chip integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spacer chip is used to support the overlying semiconductor chip, then the chip can be properly positioned and supported, but the adhesive film may flow onto the exposed upper surface of the spacer chip and invade the semiconductor chip, deteriorating reliability
Solution Approach 1:
The spacer chip is designed with a groove structure at its upper surface, creating a localized feature that changes the quality of the surface. This groove structure allows the adhesive film to be contained in a specific region rather than flowing freely onto the semiconductor chip, thus resolving the contradiction between providing support and preventing adhesive overflow.
Solution Approach 2:
The groove structure acts as an intermediary element between the adhesive film and the semiconductor chip. It provides a transition zone that captures and contains the adhesive, preventing direct contact between the adhesive and the chip surface, thereby mediating the harmful interaction.
2Strength
If high pressure and temperature are applied during the die attach process, then the adhesive film achieves proper bonding, but the adhesive gains fluidity and flows onto the spacer chip and semiconductor chip
Solution Approach 1:
The groove structure creates a localized region on the spacer chip that serves as an adhesive reservoir. This local feature allows the adhesive to be contained and utilized effectively during the bonding process, preventing both material loss and unwanted flow onto the semiconductor chip surface.
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 effectively mitigates the issue of adhesive overflow, enhancing the reliability of semiconductor packages by preventing adhesive penetration onto the semiconductor chips and reducing process defects during the molding process.
Implementation Method 1
a groove at an upper surface of the protruded portion... the adhesive film on a bottom surface of the lowermost second semiconductor chip at least partially fills the groove of the first spacer chip
Data Source
AI summary
A semiconductor package includes a package substrate, first and second spacer chips attached to an upper surface of the package substrate and spaced apart from each other, a first semiconductor chip mounted on the upper surface of the package substrate and disposed between the first and second spacer chips, a plurality of second semiconductor chips sequentially stacked on the first and second spacer chips by adhesive films to cover the first semiconductor chip, and a sealing member on the package substrate and covering the first and second spacer chips, the first semiconductor chip, and the plurality of second semiconductor chips. At least a portion of the first spacer chip protrudes from one side of a lowermost second semiconductor chip among the plurality of second semiconductor chips, and the first spacer chip includes a groove at an upper surface of the protruded portion.