Semiconductor Module Terminal Block Hole Anchoring
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Solution Overview
Problem
Semiconductor modules experience defects due to peeling of encapsulating resin during heat cycle tests, leading to electrical disconnection between terminals and semiconductor elements, caused by thermal stress and subsequent failure of bonding between wiring members and terminals.
Innovation Solution
Incorporation of through-holes in the terminal block that fill with encapsulating resin and adhesive, positioned closer to the inner frame surface than the bonding area, providing an anchor effect to prevent peeling and enhance bonding strength between the case and encapsulating resin, as well as between the case and adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulating resin is used to protect components inside the case, then the components are protected from environmental damage, but the encapsulating resin may peel away from the case due to thermal stress during heat cycle tests
Solution Approach 1:
Through-holes are formed in the terminal block before the encapsulating resin is applied, and the resin is filled into these holes in advance. This preliminary preparation creates anchor points that prevent peeling during subsequent thermal cycling, addressing the bonding stability issue before it occurs.
Solution Approach 2:
The terminal block is designed with through-holes creating a porous structure that allows the encapsulating resin to penetrate and form mechanical interlocking. This porous design enhances the bonding interface between the resin and the terminal block, preventing peeling under thermal stress while maintaining component protection.
2Reliability
If the encapsulating resin is positioned close to the terminal block to provide protection, then protection is enhanced, but peeling may progress to the terminal block and cause electrical disconnection
Solution Approach 1:
Through-holes are pre-formed in the terminal block at strategic positions before encapsulation. The encapsulating resin is filled into these holes to create anchor points that stop peeling progression before it reaches the terminal block, thus preventing electrical disconnection while maintaining close protection.
Solution Approach 2:
The encapsulating resin filled in the through-holes acts as an intermediary anchor structure between the terminal block and the main encapsulating resin body. This intermediary resin in the holes prevents direct peeling contact between the terminal block and the external environment, blocking the harmful peeling progression.
3Reliability
If the bonding part between wiring members and terminals is positioned to allow encapsulation, then electrical connection is achieved, but peeling may reach this bonding part and cause wire breakage or disconnection
Solution Approach 1:
Through-holes are formed and filled with encapsulating resin before the bonding of wiring members to terminals is completed. This preliminary resin filling creates protective anchor points around the bonding area, preventing peeling from reaching and damaging the bonding part, thus protecting electrical connection integrity.
Solution Approach 2:
The encapsulating resin filled in the through-holes serves as a cushioning layer that absorbs and distributes thermal stress before it can reach the bonding part. This beforehand cushioning prevents stress concentration at the bonding interface, protecting against wire breakage and disconnection during thermal cycling.
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
The solution significantly reduces the occurrence of electrical disconnections by improving the bond strength between the case and encapsulating resin and adhesive, thereby inhibiting peeling and extending the number of heat cycle cycles before electrical continuity is lost.
Implementation Method 1
A hole is formed in the top face of the terminal block, and the hole is filled with the encapsulating resin
Implementation Method 2
an adhesive part that sticks the frame to a base with an adhesive
Implementation Method 3
if a heat cycle test is performed for example, the encapsulating resin may peel away from the case due to thermal stress
Data Source
AI summary
A semiconductor module is provided with: a case having a frame that surrounds a substrate and a terminal block formed extending inward from an inner wall surface of the frame; a terminal having one end extending outward from the frame, and another end extending inward from the frame and being secured to a top face of the terminal block; a wiring member that electrically connects the terminal and a semiconductor element on the substrate; and an encapsulating resin that encapsulates the other end of the terminal, the wiring member, and the semiconductor element inside the case. A hole is formed in the top face of the terminal block. The hole is filled with the encapsulating resin, and is positioned closer to the inner wall surface of the frame than a bonding part between the terminal and the wiring member.