Semiconductor Module Packaging With Stepped Board Edge Sealing
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Solution Overview
Problem
Conventional semiconductor devices face issues with flame retardancy and moisture absorption reflowability due to adhesive protrusion during the dicing process, leading to potential peeling or rupture when the adhesive is exposed on the surface.
Innovation Solution
A semiconductor device configuration that includes a wiring board with a step and a sealing member covering the adhesive and module, where the adhesive is positioned between the solder balls, and the step is formed by cutting the fillet to prevent adhesive exposure, enhancing adhesion and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is injected between the module and wiring board, then adhesion strength is improved, but adhesive may protrude from the end part causing flame retardancy and moisture absorption reflowability to deteriorate
Solution Approach 1:
The protruding adhesive (fillet) is removed by dicing before the adhesive fully cures, extracting the harmful exposed adhesive from the device surface while preserving the adhesive bonding function between module and wiring board
Solution Approach 2:
The adhesive is injected and allowed to protrude slightly before dicing removes the excess, performing the adhesive injection action in advance and removing the harmful portion before final curing to prevent exposure issues
2Strength
If adhesive protrudes from the module end part, then adhesion between module and wiring board is enhanced, but the exposed adhesive on the end surface causes peeling or rupture
Solution Approach 1:
The harmful exposed adhesive that causes peeling and rupture is removed by dicing, extracting only the necessary adhesive portion that provides bonding while eliminating the unreliable exposed section
Solution Approach 2:
The adhesive is injected and positioned before dicing removes the excess, performing the bonding function in advance while preparing to remove the harmful protruding portion to ensure reliability
3Productivity
If the module is diced while connected onto the wiring board, then assembly efficiency is improved, but the protruding adhesive is exposed on the end surface causing quality issues
Solution Approach 1:
The adhesive is injected and allowed to protrude slightly before the dicing operation, performing the adhesive application in advance and then removing the excess during the same dicing process that separates modules, maintaining efficiency while controlling precision
Solution Approach 2:
The dicing operation simultaneously performs two functions: separating the modules from each other and removing the protruding adhesive from the end surfaces, extracting the harmful portion while maintaining productivity
Data Source
AI summary
According to one embodiment, a semiconductor device includes a wiring board, an adhesive, a semiconductor module, and a sealing member. The wiring board includes a step at an outer peripheral. The adhesive is provided on the wiring board. The semiconductor module is disposed on the adhesive. The semiconductor module is mounted inward from the step of the wiring board. The sealing member covers the step, a side surface of the adhesive, and the semiconductor module. The step includes a side surface and a bottom surface. The side surface faces an outside of the wiring board. The bottom surface extends from a lower end of the side surface toward an end part of the wiring board. The side surface of the step and the side surface of the adhesive are positioned to overlap with one another in a view from a stacking direction of the adhesive and the semiconductor module.