Sinter Pre-Layer for Semiconductor Substrate Bonding
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Solution Overview
Problem
Sintering processes are not suitable for joining large semiconductor substrates to base plates due to thermal expansion coefficient mismatches, which can lead to mechanical stress and reduced module lifetime.
Innovation Solution
A method involving a pre-layer with ferromagnetic or paramagnetic particles between joining members, where heat is generated contactlessly within the pre-layer using an electromagnetic field, allowing for controlled heating without directly heating the joining members, thus minimizing thermal expansion mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sintering process is used to join large semiconductor substrates to base plates, then a strong bond can be achieved, but severe mechanical stress occurs due to different thermal expansion coefficients
Solution Approach 1:
The patent introduces a sinter layer as an intermediary substance between the semiconductor substrate and base plate. This sinter layer has thermal expansion properties that are intermediate between the substrate and base plate, acting as a buffer to reduce mechanical stress while maintaining strong bonding. The sinter layer absorbs the differential expansion stress that would otherwise damage the direct bond between components with mismatched thermal expansion coefficients.
2Strength
If the joining members are heated and then cooled during sintering, then the components are pressed together to form a bond, but mechanical stress damages the sinter layer or joining members
Solution Approach 1:
The patent modifies the thermal and mechanical parameters of the joining process by introducing a sinter layer with specific properties. The sinter layer allows for controlled heating and pressing during sintering while its material properties (thermal expansion coefficient, softness) change with temperature to accommodate the bonding process. The layer undergoes parameter changes that enable it to withstand the thermal cycling and mechanical pressure without transmitting damaging stress to the semiconductor substrate or base plate.
3Ease of manufacture
If sintering processes are used for large joining members with different thermal expansion coefficients, then bonding can be achieved, but the sinter layer is corrupted or joining members are severely damaged
Solution Approach 1:
The sinter layer serves as a protective intermediary that enables manufacturing of large semiconductor modules while preserving component integrity. It provides a compliant interface that accommodates thermal expansion differences, allowing the sintering process to be applied to large substrates without corrupting the sinter layer or damaging the joining members, thus making the manufacturing process viable for large-scale production.
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 method enables a stable, substance-to-substance bond between joining members with different thermal expansion coefficients, reducing mechanical stress and extending the lifetime of semiconductor modules by allowing sintering processes to be used for any size or material of joining members.
Implementation Method 1
heat in the first pre-layer is generated contactlessly. Contactlessly generating heat in the first pre-layer comprises generating an electromagnetic field
Implementation Method 2
the at least one additional sublayer comprises ferromagnetic or paramagnetic particles, and wherein contactlessly generating heat in the first pre-layer further comprises stimulating the ferromagnetic or paramagnetic particles of the at least one additional sublayer
Implementation Method 3
applying pressure to the stack comprising the first joining member, the second joining member and the first pre-layer by means of a second part of the joining arrangement, thereby pressing the first joining member on the first pre-layer and the second joining member
Data Source
Figure 1~3
Figure 4A~4D
Figure 5~6B
AI summary
A method comprises arranging a second joining member (20) on a flat contact surface of a first part (41) of a joining arrangement; arranging a first pre-layer (31) on a surface of the second joining member (20) which faces away from the flat contact surface of the first part (41); arranging a first joining member (10) on the first pre-layer (31) such that the first pre-layer (31) is arranged between the first joining member (10) and the second joining member (20); applying pressure to the stack comprising the first joining member (10), the second joining member (20) and the first pre-layer (31) by means of a second part (42) of the joining arrangement, thereby pressing the first joining member (10) on the first pre-layer (31) and the second joining member (20); and directly heating the first pre-layer (31) without directly heating the joining members (10, 20), wherein heat in the first pre-layer (31) is generated contactlessly.