Semiconductor Underfill Injection Section for Void Prevention
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Solution Overview
Problem
In chip-on-chip type semiconductor devices, the filling process of underfill material often results in voids and climbing issues due to surface tension and manufacturing variations, leading to reduced connection reliability and yield, especially with the miniaturization and lamination of chips.
Innovation Solution
A semiconductor device structure with an injection section on the mounted body guides the underfill material to the side section of the semiconductor chip, allowing it to penetrate between the chip and the mounted body via capillary phenomenon, forming a fillet on the outer peripheral part and preventing voids and climbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the underfill material is supplied to fill the gap between chips, then the connection reliability is improved, but voids and climbing occur due to surface tension and manufacturing variations
Solution Approach 1:
The patent introduces an injection section as an intermediary structure between the underfill material supply and the chip gap. This injection section serves as a mediator that guides and controls the flow of underfill material, ensuring uniform penetration into the gap while preventing harmful effects like voids and climbing. The injection section acts as a buffer and directional guide, resolving the contradiction between achieving reliable filling and maintaining manufacturing precision.
Solution Approach 2:
The patent modifies the physical parameters of the filling process by controlling the flow characteristics of the underfill material through the injection section. By changing parameters such as flow rate, penetration depth, and distribution uniformity, the injection section ensures that the underfill material fills the gap uniformly without causing voids or climbing, thus resolving the contradiction between connection reliability and filling precision.
2Productivity
If the wet spread property of the chip surface is increased to enable voidless penetration, then the filling efficiency is improved, but the surface tension blocks the fluidity at stepped portions
Solution Approach 1:
The injection section serves as an intermediary that bridges the gap between the underfill material and the chip gap, controlling the material's flow path. This intermediary structure allows the underfill material to penetrate the gap efficiently without being blocked by surface tension at stepped portions, as the injection section guides the material flow in a controlled manner that overcomes the blocking effect.
Solution Approach 2:
The patent applies local quality by creating a specific flow environment within the injection section that differs from the general chip surface. The injection section provides a localized region with optimized flow characteristics, allowing the underfill material to maintain its fluidity and penetrate efficiently without being affected by the surface tension blocking that occurs at stepped portions on the chip surface.
3Manufacturing precision
If the amount of underfill material is increased to ensure complete filling, then the filling completeness is improved, but climbing occurs on the chip surface
Solution Approach 1:
The injection section acts as a mediator that controls and regulates the amount of underfill material that enters the chip gap. By providing this intermediary structure, the system can supply sufficient material for complete filling without excess material remaining on the chip surface, thus preventing climbing while ensuring filling completeness.
Solution Approach 2:
The injection section changes the flow parameters of the underfill material, controlling the rate and distribution of material entry into the gap. This parameter control ensures that the exact amount of material needed for complete filling is supplied, preventing both insufficient filling and excessive material that would cause climbing.
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 enhances the connection reliability and yield by ensuring uniform and voidless filling of the underfill material, preventing climbing and void formation, thus improving the overall performance and reliability of the semiconductor device.
Implementation Method 1
The underfill material 5 wets and spreads on the surface of the first semiconductor chip 1, reaches the end of the second semiconductor chip 2, and penetrates a gap between the chips by a capillary phenomenon
Implementation Method 2
the wet spread property of the surface of the first semiconductor chip 1 is high, that is, the surface tension is small
Data Source
AI summary
A semiconductor device includes: a mounted body in which a wiring pattern is formed on a first main surface; a semiconductor chip mounted on the surface of the mounted body on which the wiring pattern is formed; an underfill material which is filled between the mounted body and the semiconductor chip and forms a fillet on an outer peripheral part of the semiconductor chip; and an injection section which is disposed on the mounted body and on an outside of a side section, on which the fillet is formed to be longest, of four side sections defining a chip mount area on which the semiconductor chip is mounted, and guides the underfill material to between the mounted body and the semiconductor chip.