Semiconductor Lead Grooves for Thermal Stress Relief
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Solution Overview
Problem
In resin-sealed semiconductor devices, the difference in linear expansion coefficients between the sealing resin and leads leads to exfoliation and crack formation during heat cycle tests, resulting in breakage of bonding wires and reduced reliability.
Innovation Solution
The semiconductor device incorporates grooves on the leads, specifically an inner groove between the wire connection part and the tip of the lead, and an outer groove between the wire connection region and the other end of the lead, to reduce shearing stress and prevent exfoliation, enhancing the adhesive force and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grooves are provided in the lead to prevent exfoliation and enhance reliability, then the adhesive force and mechanical strength are improved, but the manufacturing complexity and device structure become more complex
Solution Approach 1:
The lead surface is segmented into multiple grooves that divide the contact area between the sealing resin and lead. These grooves create multiple small bonding zones instead of one large bonding area, which distributes the thermal stress and prevents exfoliation while maintaining overall structural integrity
Solution Approach 2:
The grooves are strategically positioned at specific locations on the lead where thermal stress concentration occurs. By modifying only these critical local areas rather than the entire lead surface, the invention enhances reliability at stress points while minimizing overall structural complexity
2Reliability
If grooves are provided in the lead to increase contact area with sealing resin, then the adhesive force is improved, but the manufacturing process becomes more difficult
Solution Approach 1:
The grooves are formed on the lead surface before the sealing resin is applied. This preliminary structuring of the lead surface allows the sealing resin to naturally flow into and bond with the groove structures during the encapsulation process, enhancing adhesive force without requiring additional post-assembly manufacturing steps
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
The grooves effectively prevent exfoliation and crack formation, thereby enhancing the reliability of the semiconductor device by reducing shearing stress and increasing the contact area between the sealing resin and leads, thus preventing wire breakage.
Implementation Method 1
the difference in linear expansion coefficients between the sealing resin and leads leads to exfoliation and crack formation during heat cycle tests
Data Source
AI summary
A semiconductor device has a semiconductor chip, a signal lead that is arranged in a periphery of the semiconductor chip and has a main surface and a rear surface opposed to the main surface, a wire that electrically connects the semiconductor chip and the main surface of the signal lead, and a sealing body made of sealing resin that seals the semiconductor chip, the signal lead and the wire. The signal lead has, in an extending direction of the signal lead, one end located inside the sealing body, the other end located outside the sealing body, and a wire connection region which is the main surface of the signal lead and to which the wire is connected, and an inner groove is provided in the main surface of the signal lead between the one end and the wire connection region.