Pre-sintering Carrier for Two-sided Sintering Paste Application
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Solution Overview
Problem
Existing methods for producing power semiconductor substrates face challenges in reliably printing sintering paste on both sides of joining partners, especially with complex geometries, and require pre-sintering steps that limit sintering activity and complicate handling.
Innovation Solution
A method involving pre-sintering carriers with non-sinterable surfaces, where sintering paste is applied and dried on these carriers, and then pressed with connecting objects to increase adhesive force, allowing for removal and placement on insulating base bodies for further sintering, enabling both-sided paste application and connection without pre-sintering limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sintering paste is printed directly on joining partners (substrate or conductor track), then the paste can be applied to the bonding surface, but it becomes difficult to print on both sides without pre-sintering and the structure is difficult to handle
Solution Approach 1:
The patent introduces a pre-sintered carrier as an intermediary object that temporarily holds the sintering paste during the bonding process. The carrier serves as a stable support that allows paste application on both sides without requiring the substrate itself to be pre-sintered, thereby improving handling ease while maintaining manufacturing feasibility
Solution Approach 2:
The carrier is pre-sintered before use to create a stable, non-deformable support surface. This preliminary action ensures the carrier maintains its shape and position during paste application and bonding operations, enabling reliable two-sided paste application without compromising the substrate
2Reliability
If pre-sintering is performed on one side of the component, then the paste adheres to that side, but the sintering activity of the first pre-sintered layer is limited when a second pre-sintering step is required
Solution Approach 1:
The pre-sintered carrier acts as a mediator that provides initial adhesion support without consuming the sintering activity of the substrate. The carrier's pre-sintered surface allows the paste to adhere reliably during handling, while the substrate remains fully active for the final bonding sintering operation
Solution Approach 2:
The bonding system is segmented into two functional parts: the pre-sintered carrier that provides temporary adhesion support, and the substrate that performs the final bonding function. This segmentation allows each component to optimize its specific function without interfering with the other's performance
3Ease of manufacture
If a preform foil is inserted between joining partners to enable two-sided paste printing, then paste application becomes possible, but positioning is difficult and preform foils are not suitable for complicated geometries
Solution Approach 1:
The pre-sintered carrier serves as a precision intermediary that incorporates positioning features directly into its structure. The carrier's rigid, pre-sintered nature allows for accurate positioning and alignment during paste application, overcoming the positioning difficulties associated with flexible preform foils
Solution Approach 2:
The carrier undergoes parameter changes through pre-sintering, transforming from a deformable state to a rigid, dimensionally stable state. This parameter change enables precise positioning and maintains geometric accuracy during subsequent handling and bonding operations
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 allows for efficient, reliable application of sintering paste on both sides of power semiconductor substrates, facilitating the production of substrates with circuit-structured conductor tracks and enabling connection of components without the need for pre-sintering steps, thus improving handling and sintering activity.
Implementation Method 1
pressurizing the assembly consisting of the second pre-sinter substrate and the bonding surface object and the first and second dried sintering paste
Implementation Method 2
the adhesive force between the dried sintered paste and the bonding surface object becomes greater than the adhesive force between the sintering paste layer and the carrier film
Data Source
Figure 1a~1f
Figure 2a~2f
Figure 3a~3k
AI summary
The method involves arranging a connecting surface object on associated surface portions (12, 14) of a dried sintering paste (16). The object is removed from a pre-sintering support (10) that is provided with the paste such that the paste produces a corresponding semi-finished product. The product is arranged in an electrically insulating flat base body, where the sintering paste faces toward the body. A structure is sintered-loaded in the product and the body with pressure and elevated temperature for longer time period for forming a sintered power semiconductor substrate.