Semiconductor Device Convex Insulation Film Crack Prevention
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Solution Overview
Problem
Existing semiconductor devices face challenges in preventing the development of cracks in solder layers due to thermal stress, as previous techniques only partially address the issue of crack prevention after its occurrence.
Innovation Solution
A semiconductor device design featuring a substrate with an insulation film having a convex protrusion, a metal film covering the convex, and solder on top, which stops crack propagation by creating a barrier at the boundary between the metal film and insulation film when thermal expansion differences cause cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solder layer is used in a semiconductor device, then electrical connection and thermal conduction are improved, but cracks occur in the solder layer due to thermal stress from temperature rise
Solution Approach 1:
The patent applies local quality by creating a convex portion with different material properties at a specific location in the insulation film. This convex portion has higher strength and different thermal expansion characteristics compared to the surrounding insulation film, allowing it to locally bear thermal stress and prevent crack propagation in the solder layer while maintaining overall device functionality.
Solution Approach 2:
The convex portion acts as a pre-positioned stress buffer that absorbs and distributes thermal stress before cracks can form or propagate in the solder layer. By having this reinforced structure in place beforehand, the patent prevents the worsening of solder layer integrity under thermal cycling conditions.
2Reliability
If the solder layer is made with solid-solubilized-hardening type solder material, then crack occurrence is prevented, but crack development after occurrence cannot be sufficiently prevented
Solution Approach 1:
The convex portion serves as an intermediary structure between the solder layer and the insulation film. It mediates the stress distribution and provides a barrier that stops crack propagation, thereby extending the device service life by preventing cracks from developing even when they initially occur in the solder layer.
3Reliability
If a convex structure is added to the insulation film, then crack propagation is stopped, but device complexity increases
Solution Approach 1:
The convex portion segments the insulation film structure into distinct regions with different mechanical properties. This segmentation creates a localized reinforcement that stops crack propagation without requiring complex changes to the entire insulation film or device structure, thus limiting the increase in device complexity.
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
Effectively prevents crack development by using the convex structure to halt crack propagation, ensuring the integrity of the semiconductor device under thermal stress.
Implementation Method 1
a crack might occur at a boundary of the sealing resin and the solder, due to a difference between the sealing resin and the solder in thermal expansion coefficient
Data Source
AI summary
A semiconductor device 1 is provided with a semiconductor substrate 10, an electrode 30 formed on a surface of the semiconductor substrate 10, and an insulation film 20 formed on the electrode 30. The semiconductor device 1 includes a metal film 40 extending over a part of the surface of the electrode 30 not covered by the insulation film 20 and a surface of the insulation film 20. The semiconductor device 1 includes solder 80 formed on a surface of the metal film 40, a lead frame 50 joined to the metal film 40 by the solder 80, and sealing resin 60 sealing the insulation film 20, the metal film 40, and the solder 80. A convex 70 is formed on the surface of the insulation film 20. The metal film 40 covers the convex 70. The solder 80 covers the metal film 40 covering the convex 70.