Stepped Link Portion Lead Frame for Thin Semiconductor Packages
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Solution Overview
Problem
Reducing the thickness of semiconductor apparatuses while minimizing deformation of the lead frame during mounting and encapsulation, as thinner lead frames are prone to deformation during these processes.
Innovation Solution
A lead frame design featuring a die pad portion, lead portions, and link portions, where the link portions connect the die pad and lead portions, with specific surface configurations to maintain structural integrity and allow for thickness reduction without deformation, and a method of manufacturing involving half-etching and plating processes to form the lead frame and semiconductor apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the lead frame is reduced to reduce semiconductor apparatus thickness, then the thickness of the semiconductor apparatus is reduced, but the lead frame is deformed during mounting or encapsulation
Solution Approach 1:
The patent introduces a stepped structure in the link portion with different thickness levels (first thickness and second thickness). This dimensional variation within the same component allows the link portion to provide structural support where needed while maintaining overall thinness, thus reducing semiconductor apparatus thickness without causing lead frame deformation during mounting or encapsulation.
Solution Approach 2:
The link portion has different thickness regions: a first thickness in the region between the die pad and lead, and a second thickness in other regions. This local quality variation allows specific areas to have the structural strength needed to prevent deformation while other areas remain thin to reduce overall apparatus thickness.
2Length of moving object
If the thickness of the lead frame is reduced, then the semiconductor apparatus becomes thinner, but the structural integrity of the lead frame deteriorates
Solution Approach 1:
The stepped structure creates varying thickness levels within the link portion, providing structural reinforcement in critical areas while maintaining thin overall profile. This dimensional variation preserves structural integrity without sacrificing thickness reduction.
Solution Approach 2:
The link portion functions as a composite structure with different thickness regions serving different structural roles. The thicker regions provide strength and support, while thinner regions reduce overall mass and thickness, creating a composite-like behavior within a single material component.
Data Source
AI summary
A lead frame including a die pad having a first surface and a second surface opposite the first surface, a lead having a third surface flush with the first surface and a fourth surface opposite the third surface, and a link portion connecting the die pad and the lead, wherein the link portion includes a first portion that surrounds the die pad between the die pad and the lead in a plan view, wherein the first portion has a fifth surface flush with the first surface and the third surface, and has a sixth surface opposite the fifth surface, wherein the second surface is closer to a plane containing the first surface, the third surface, and the fifth surface than is the fourth surface, and wherein the sixth surface is closer to the plane containing the first surface, the third surface, and the fifth surface than is the second surface.