Overmoulded Power Substrate Assembly for Precise MOSFET Positioning
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Solution Overview
Problem
Modern power substrates with ceramic construction and metallic surfaces face challenges in accurately and reliably positioning electrical components like IGBTs and MOSFETs, which is crucial for low-inductive designs, especially in switching modules with SiC MOSFETs, due to limited two-dimensional compensation capabilities.
Innovation Solution
The solution involves an electrotechnical arrangement where a circuit substrate is overmoulded with an insulating element featuring a demoulding chamfer or catching funnel that allows for flexible centering in the Z direction, enabling precise positioning of electrical components by sliding them along a flank, which can be elastic, to reduce initial tolerances and ensure accurate alignment before electrical or mechanical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrical components are positioned on a ceramic power substrate using conventional two-dimensional bonding methods, then the assembly process is simple, but the positioning accuracy and reliability are insufficient for low-inductive designs
Solution Approach 1:
The patent transitions from conventional two-dimensional positioning on the substrate surface to three-dimensional positioning using a vertical catching funnel structure. The funnel's inclined flank guides the electrical component from above, enabling precise positioning in the Z-direction (vertical axis) while maintaining simplicity in the assembly process. This dimensional transition resolves the contradiction by providing high positioning accuracy without significantly complicating the assembly procedure.
Solution Approach 2:
The catching funnel acts as an intermediary structure between the substrate and the electrical component. It provides a guided pathway that automatically centers and positions the component during insertion, eliminating the need for complex alignment procedures. The funnel's geometry serves as a passive guiding mechanism that ensures precise positioning while keeping the assembly process straightforward.
2Manufacturing precision
If the component is pressed onto the circuit substrate with high force to ensure exact positioning, then the positioning precision improves, but the risk of deformation or damage increases
Solution Approach 1:
The catching funnel performs preliminary positioning action during the insertion phase, before the final pressing operation. The inclined flank guides the component into the correct position early in the assembly process, so that subsequent pressing forces are applied to an already-aligned component. This prevents excessive deformation while maintaining positioning precision, as the component is guided rather than forced into position.
Solution Approach 2:
The funnel structure provides a gradual transition zone that cushions the impact and distribution of pressing forces. Instead of direct vertical pressing onto the component, the inclined surfaces distribute the force gradually, preventing sudden shocks that could cause deformation or damage while still achieving exact positioning at the bottom of the funnel.
3Manufacturing precision
If the insulating element is designed with a vertical flank for exact positioning, then the positioning accuracy is high, but the demoulding process becomes difficult
Solution Approach 1:
The insulating element features an asymmetric cross-section with an inclined flank on one side and a vertical flank on the other. The inclined flank facilitates demoulding by providing a smooth escape path for the component, while the vertical flank maintains positioning accuracy. This asymmetric design resolves the contradiction by combining both functions in a single structure.
Solution Approach 2:
The insulating element's flank is segmented into two distinct functional zones: an inclined section for demoulding and a vertical section for positioning. This segmentation allows each zone to optimize its specific function without compromising the other, enabling both easy demoulding and high positioning accuracy in the same component.
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 safe, reliable, and accurate positioning of electrical components, reducing initial tolerances and preventing electrical short circuits, while also varying air and creepage distances, thus facilitating a low-inductive design suitable for SiC MOSFET switching modules.
Implementation Method 1
The component can be pressed onto the circuit substrate, while the section located in the region of the flank of the foot is clamped by this process and optionally even forcibly deformed/biased. In particular, this part of the component can be decelerated by the friction on the flank
Data Source
AI summary
The invention relates to an electronic control unit, an electrotechnical arrangement, and a method for producing an electrotechnical arrangement. The electrotechnical arrangement (10) comprises a circuit substrate (3), an electrical component (2), and an insulating element (4); wherein the circuit substrate (3) is overmoulded with the insulating element (4), the insulating element (4) has a flank (5) which is aligned at an angle with respect to a direction Z defined perpendicularly to a surface of the circuit substrate (3), and the component (2) is fixed on the circuit substrate (3) at the foot of the flank (5) of the insulating element (4).