Semiconductor Chip Mounting Structure for Thermal Cycling Reliability
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Solution Overview
Problem
Semiconductor devices face reliability issues due to the formation of cavities in the solder bond between the semiconductor chip and the circuit board, leading to stress and damage when subjected to thermal cycling, which deteriorates the device's performance.
Innovation Solution
A semiconductor device manufacturing method involving the formation of a supporting portion around the disposition area on a conductive plate, coating the semiconductor chip and supporting portion with a coating layer, and sealing with sealing material to prevent stress-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor chip is bonded to a circuit pattern of an insulating circuit board via solder, then the electrical connection is established, but a cavity could be formed in the solder leading to stress and damage during thermal cycling
Solution Approach 1:
A supporting portion is formed in advance in the periphery of the disposition area on the conductive plate before the semiconductor chip is bonded. This supporting portion protrudes upward from the bottom of the disposition area to provide preliminary structural support that prevents cavity formation in the solder during subsequent bonding and thermal cycling processes.
Solution Approach 2:
The supporting portion acts as a cushioning structure formed beforehand to compensate for and prevent the harmful effect of cavity formation. By providing this supporting structure in advance, the patent prevents the solder from forming cavities that would otherwise cause stress and damage during thermal cycling, thereby protecting the semiconductor chip.
2Reliability
If sealing material is applied to seal the semiconductor chip, then the chip is protected from environmental factors, but the sealing material flows into the cavity under the chip causing stress and damage
Solution Approach 1:
The supporting portion is formed in advance before sealing material is applied. This preliminary structure prevents the sealing material from flowing into cavities under the semiconductor chip during the sealing process, eliminating the source of stress and damage that would occur during thermal cycling.
3Strength
If coating material is applied to the inside of the case before sealing, then adhesion between components and sealing material is improved, but the coating process becomes more complex
Solution Approach 1:
A coating layer is formed on the front surface of the conductive plate, including the semiconductor chip and supporting portion, before sealing. This preliminary coating action improves adhesion between the components and sealing material while the supporting portion ensures the coating is applied uniformly without flowing into cavities.
Data Source
AI summary
A semiconductor device manufacturing method includes preparing a semiconductor chip and a conductive plate having a front surface that includes a disposition area on which the semiconductor chip is to be disposed, forming a supporting portion in a periphery of the disposition area of the conductive plate such that the supporting portion protrudes from a bottom of the disposition area in an upward direction orthogonal to the front surface of the conductive plate, bonding the semiconductor chip to the disposition area via bonding material applied to the disposition area, coating the front surface of the conductive plate, including the semiconductor chip and the supporting portion, with a coating layer, and after the coating, sealing the front surface of the conductive plate, including the semiconductor chip and the supporting portion, with sealing material.