Semiconductor Leadframe Resin Sealing via Matrix Cavity and Corner Support
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Solution Overview
Problem
The existing resin sealing technologies for semiconductor devices face challenges in increasing the yield of semiconductor devices from a leadframe due to the need for a runner portion, which also increases production costs, and the placement of ejector pins interferes with support pillars in through mold systems.
Innovation Solution
A SEMI-MAP system is employed, where a leadframe is sandwiched between mold dies with a matrix-state cavity group, and a support pillar is placed at the cavity corner to prevent mold die deformation, allowing for efficient resin sealing and release without interfering with ejector pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a runner portion is provided on the leadframe for supplying resin to each cavity, then resin supply is enabled, but the number of semiconductor devices available from the leadframe decreases
Solution Approach 1:
The runner portion is extracted from the leadframe and relocated to the mold die. The cavity block in the mold die now includes integrated runner portions that supply resin to cavities, eliminating the need for runner portions on the leadframe itself. This allows the leadframe to be fully utilized for mounting semiconductor devices, increasing the number of devices per leadframe while maintaining resin supply capability.
2Reliability
If ejector pins are provided in each cavity for release, then good release properties are ensured, but the placement of support pillars is interfered with
Solution Approach 1:
The support pillars are repositioned from the cavity floor to the cavity corner portions. By changing the spatial location of support pillars to the corners where cavities meet, they no longer interfere with the ejector pins positioned at the center of cavity bottoms. This dimensional repositioning allows both support pillars and ejector pins to coexist without interference, maintaining structural support and release functionality.
3Productivity
If a through gate system is used to link cavities, then the runner portion on leadframe is eliminated, but ejector pins interfere with support pillars
Solution Approach 1:
The support pillars are repositioned from the cavity floor to the cavity corner portions. By changing the spatial location of support pillars to the corners where cavities meet, they no longer interfere with the ejector pins positioned at the center of cavity bottoms. This dimensional repositioning allows both support pillars and ejector pins to coexist without interference, maintaining structural support and release functionality.
Data Source
AI summary
When chip-scale molding system is employed for QFP, the number of semiconductor devices available from a leadframe decreases because cavities each requires a runner portion. This problem can be overcome by employing MAP system, but use of a laminate tape increases the production cost. In through mold system, each cavity needs an ejector pin, which however makes it difficult to place a support pillar. The present application provides a manufacturing method of a semiconductor device by filling, while sandwiching a leadframe between mold dies having a matrix-state cavity group in which cavity columns obtained by linking mold cavities in series via a through gate have been placed in rows, a sealing resin in the cavities. In this method, the matrix-state cavity group has, at the cavity corner portions thereof, a support pillar having a cross-section striding over all the cavities adjacent to the cavity corner portions when viewed planarly.