Semiconductor Module Sintering With Insulating Sheet Pressure Equalization
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Solution Overview
Problem
Existing semiconductor modules face challenges in achieving stable joining quality at high temperatures due to uneven pressure application during sintering, leading to potential air bubbles and unreliable bonding between semiconductor chips and other components.
Innovation Solution
A semiconductor module manufacturing method involving an insulating wiring substrate, semiconductor chip, and printed wiring board, where a sintering material is used to join the components, and an insulating sheet surrounds the chip to ensure uniform pressure and heat application during heating, preventing bending of the lead frame and uneven pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintering material is used to join semiconductor chip to insulating wiring substrate and printed wiring board, then heat dissipation effectiveness is improved, but uneven pressure application during sintering causes air bubbles and unstable joining quality
Solution Approach 1:
An insulating sheet is introduced as an intermediary component between the insulating wiring substrate and the printed wiring board. This sheet has a larger area than both the semiconductor chip and the via-hole, creating a broader contact area that distributes and equalizes pressure during the sintering process, thereby preventing air bubbles and ensuring uniform pressure application across the sintering material.
Solution Approach 2:
The insulating sheet extends in the planar dimension (area) beyond the boundaries of the semiconductor chip and via-hole, transitioning from a point-contact or small-area contact to a large-area contact. This dimensional expansion in the horizontal plane enables more uniform pressure distribution across the sintering interface, resolving the pressure uniformity issue.
2Strength
If pressure is applied during sintering to ensure good contact, then joining strength is improved, but uneven pressure distribution leads to air bubbles and unreliable bonding
Solution Approach 1:
The insulating sheet serves as a pressure-distributing intermediary that receives applied pressure and redistributes it uniformly across the sintering material interface. This mediator prevents localized high-pressure points and ensures consistent pressure distribution, eliminating air bubbles while maintaining strong, reliable bonds between components.
Solution Approach 2:
The insulating sheet creates a homogeneous pressure distribution across the sintering interface by its larger contact area. This homogenization of pressure ensures that the sintering material bonds uniformly throughout, producing consistent bonding strength and reliability without defects caused by pressure variations.
3Ease of manufacture
If lead frame is left exposed during sintering, then manufacturing simplicity is maintained, but lead frame bending occurs due to uneven pressure and heat application
Solution Approach 1:
The insulating sheet acts as a protective intermediary that covers and supports the lead frame during the sintering process. By providing a broad, stable surface, it prevents the lead frame from bending under uneven pressure or thermal stress, while the simple structure of the sheet itself adds minimal complexity to the manufacturing process.
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 enhances the reliability and durability of semiconductor modules by achieving stable sintered bodies with high heat conductivity, reducing heat generation, and maintaining heat dissipation effectiveness even at high temperatures, while minimizing manufacturing steps and costs.
Implementation Method 1
a sintering metal layer using sintering action of metal particles of silver (Ag), copper (Cu), or the like has been considered
Implementation Method 2
achieving stable sintered bodies with high heat conductivity, reducing heat generation, and maintaining heat dissipation effectiveness even at high temperatures
Data Source
AI summary
A semiconductor module manufacturing method includes: preparing an insulating wiring substrate 10 including a substrate and a first conductor provided on the substrate, a semiconductor chip 20 having a first surface and a second surface, and a printed wiring board 50 including an insulating substrate and a lead frame 52 provided on the insulating substrate, the lead frame including a first portion 52a provided in a first via-hole penetrating through the insulating substrate; disposing the first surface on the first conductor via a first sintering material; disposing an insulating sheet on the insulating wiring substrate to surround the semiconductor chip; disposing the printed wiring board such that the insulating substrate faces the insulating sheet and the first portion makes contact with the second surface via a second sintering material; and heating the insulating wiring substrate, the semiconductor chip, the insulating sheet, and the printed wiring board while they are pressurized.