Semiconductor Terminal Laser Welding Gap Control
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Solution Overview
Problem
The existing methods for producing semiconductor devices with laser welding between upper and lower terminals face challenges in achieving sufficient bonding strength, leading to variations in bonding strength, increased production costs, and reduced assemblability due to tight dimension tolerances and the need for multiple welding points.
Innovation Solution
A method that involves creating a gap of 20 μm to 400 μm between the upper and lower terminals during laser welding, using step portions, burr portions, or gap securing members to enhance bonding strength and reduce production costs by increasing the dimension and assembly tolerances, thereby improving assemblability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the upper and lower terminals are laser welded while close-contacting each other, then the bonding strength varies, but the manufacturing process is simple
Solution Approach 1:
A gap of 20μm to 400μm is preliminarily formed between the upper and lower terminals before laser welding through mechanical means (pressing, loading, or positioning structures). This preliminary gap creation ensures consistent bonding strength during welding without requiring tight dimension tolerances on the terminals themselves.
2Strength
If multiple welding points are used to ensure sufficient bonding strength, then the bonding strength is improved, but the production cost increases
Solution Approach 1:
The gap distance parameter between terminals is optimized to 20μm to 400μm, which enables sufficient bonding strength to be achieved at a single welding point. This parameter optimization eliminates the need for multiple welding points while maintaining high bonding strength, thereby reducing production costs.
3Strength
If a small gap of about 10μm is provided between terminals for laser welding, then the bonding strength is improved, but the assemblability is reduced
Solution Approach 1:
Instead of relying on tight manufacturing tolerances to achieve a small 10μm gap, the invention preliminarily forms a larger gap (20μm to 400μm) through mechanical means such as pressing devices, loading structures, or positioning protrusions. This approach maintains bonding strength while significantly improving assemblability and dimension tolerance.
Solution Approach 2:
The gap distance is changed from a small 10μm to a larger range of 20μm to 400μm, which is formed through mechanical positioning rather than tight tolerances. This parameter change improves assemblability while maintaining sufficient bonding strength for laser welding.
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 increases the bonding strength per point, reduces the number of welding points, and lowers production costs by allowing for larger dimension and assembly tolerances, while maintaining high bonding strength and assemblability.
Implementation Method 1
a laser beam 67 is radiated to the surfaces of the emitter upper terminal 62 and the collector upper terminal 63. With this irradiation, the laser beam 67 is absorbed by the outermost surfaces of the upper terminals 62 and 63 and is then converted into thermal energy.
Implementation Method 2
the adhesive 65 is heated and hardened to fix the resin case 64 and the heat dissipating base 51
Implementation Method 3
heat is applied to melt the solders 52, 56, 58, and 59 and the solders 52, 56, 58, and 59 are cooled and re-solidified such that the members are fixed and integrated by the solders
Data Source
AI summary
A method for producing a semiconductor device includes laser welding to bond an upper terminal and a lower terminal as internal wiring members of the semiconductor device. When the upper terminal is fixed to the lower terminal by the laser welding, a gap between an upper surface of the lower terminal and a lower surface of the upper terminal is equal to or more than 20 μm and equal to or less than 400 μm.