Cylindrical Metal Pile for Semiconductor Module Gap Control
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Solution Overview
Problem
Conventional semiconductor modules face challenges in gap control between semiconductor devices and printed wiring boards, particularly when the devices have different thicknesses, leading to warping and reduced insulation performance and structural reliability due to the rigidity of flat copper wires.
Innovation Solution
The use of cylindrical metal piles that can penetrate through the printed wiring board and follow omnidirectional warps of the insulated circuit board, allowing for precise gap control and enhanced filling performance of sealing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flat type copper wires are used to connect semiconductor devices to printed wiring board, then current carrying capability is achieved, but gap control accuracy deteriorates due to rigidity in lateral directions
Solution Approach 1:
The patent changes the geometric parameters of the connection element from a flat plate shape to a cylindrical wire shape. This parameter change enables the connection element to deform laterally and follow the warp of the insulated circuit board, thereby achieving accurate gap control between the semiconductor device and printed wiring board while maintaining insulation performance.
Solution Approach 2:
The patent employs a cylindrical shape for the connection element instead of a flat plate. The curved cylindrical geometry provides flexibility in lateral directions, allowing the element to conform to three-dimensional warps of the circuit board and maintain uniform gap control, resolving the contradiction between structural rigidity and gap control precision.
2Manufacturing precision
If folded copper wires are used to accommodate height variations, then gap control becomes easier, but residual stress and bending stress increase
Solution Approach 1:
The patent applies preliminary action by pre-forming the connection element as a cylindrical wire with appropriate length and flexibility before assembly. This preliminary preparation allows the wire to naturally accommodate height variations and board warp without requiring post-assembly folding, thereby achieving gap control while avoiding the introduction of residual stress and bending stress.
3Manufacturing precision
If interval between copper wires is increased to make height uniform, then gap control improves, but package size increases
Solution Approach 1:
The patent changes the geometric parameters of individual connection elements to cylindrical wires with optimized dimensions. This parameter change allows wires to be placed closer together while still achieving uniform gap control through their ability to deform and follow board warp, thereby improving gap control without increasing overall package volume.
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 solution improves insulation performance and structural reliability by ensuring uniform gaps and effective sealing, even with devices of varying thicknesses, while reducing residual stress and maintaining high current handling capabilities.
Implementation Method 1
The cylindrical portion moves with respect to the through-hole, so that the metal pile and the printed wiring board can follow the warp of the insulated circuit board in the vertical direction
Implementation Method 2
The cylindrical portion is easily deformed in the lateral direction. Therefore, the metal pile and the printed wiring board can follow omnidirectional three-dimensional warps of the insulated circuit board
Implementation Method 3
a lower end bonded to an upper surface of the semiconductor device and a cylindrical portion penetrating through the through-hole and bonded to the printed wiring board
Data Source
AI summary
A semiconductor module includes: an insulated circuit board; a semiconductor device mounted on the insulated circuit board; a printed wiring board arranged above the insulated circuit board and the semiconductor device and having a through-hole; a metal pile having a lower end bonded to an upper surface of the semiconductor device and a cylindrical portion penetrating through the through-hole and bonded to the printed wiring board; a case surrounding the insulated circuit board, the semiconductor device, the printed wiring board and the metal pile; and a sealing material sealing an inside of the case.