Heat Sink Engagement Relocation for Semiconductor Package Mounting
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Solution Overview
Problem
Existing semiconductor devices with lead frames fixed by swaging on the upper surface of a heat sink hinder size reduction due to regions on the heat sink that cannot be used for component mounting.
Innovation Solution
A semiconductor device design where the engagement part of the heat sink is positioned to avoid the mounting surface, allowing the lead frame to be engaged without obstructing component mounting, and using a heat sink with a mounting surface, heat radiation surface, and side surface, sealed with mold resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lead frame is fixed by swaging with a dowel on the upper surface of the heat sink, then the lead frame and heat sink are securely connected, but a region on the upper surface of the heat sink cannot be used for component mounting
Solution Approach 1:
The engagement part is relocated from the upper surface (two-dimensional plane) to the side surface of the heat sink, utilizing a different spatial dimension. This allows the lead frame to be securely engaged through lateral positioning and swaging without occupying any area on the mounting surface, thus resolving the contradiction between connection strength and mounting area availability
Solution Approach 2:
The engagement function is extracted from the upper surface of the heat sink and relocated to the side surface. By separating the engagement part from the mounting surface, the patent eliminates the conflict between these two functions, allowing the upper surface to be fully dedicated to component mounting while the side surface handles the mechanical engagement
2Stability of the object's composition
If trapezoidal convex parts are provided at both ends of the heat sink for fitting, then the lead frame is securely positioned, but component mounting cannot be performed on the heat sink upper surface
Solution Approach 1:
The positioning function is moved from the upper surface to the side surface of the heat sink. The engagement part on the side surface provides lateral positioning and stability for the lead frame without interfering with the upper surface mounting area, thus maintaining positioning stability while preserving full mounting area
3Strength
If a lead is inserted into an attachment opening penetrating through the loading member, then the lead frame is securely attached, but a region on the loading member surface cannot be used for mounting
Solution Approach 1:
The attachment mechanism is relocated from a vertical penetration through the loading member to a lateral engagement through the side surface of the heat sink. This dimensional change allows secure attachment without creating openings or obstacles on the upper mounting surface
Data Source
AI summary
A semiconductor device, including: a heat sink which has a mounting surface, a heat radiation surface, a side surface and an engagement part, a semiconductor chip which is mounted on the mounting surface of the heat sink, a lead frame which is engaged with the engagement part of the heat sink, and a mold resin which seals the heat sink, the semiconductor chip and the lead frame, wherein the engagement part of the heat sink is disposed at a place which avoids the mounting surface of the heat sink. The engagement part of the heat sink is a dowel formed in the heat radiation surface of the heat sink. Further, the engagement part of the heat sink is a dowel formed in the side surface of the heat sink.