Lead Frame Insulating Resin Layer Oxidation Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lead frames for semiconductor devices suffer from oxidation of copper leads, leading to increased wiring resistance due to exposed side surfaces after dicing, which affects insulation reliability and device performance.
Innovation Solution
A lead frame design featuring an insulating resin layer that completely covers the side surfaces of leads, eliminating the need for support bars and section bars, and optionally incorporating heat radiating plates and plating layers to enhance insulation and heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead frame uses conventional structure with support bars and section bars, then the leads are mechanically supported, but the side surfaces of leads are exposed and oxidize after dicing
Solution Approach 1:
The patent removes the conventional support bars and section bars from the lead frame structure. Instead, the insulating resin layer itself provides the supporting function, while simultaneously covering and protecting the lead side surfaces from oxidation. This extraction of unnecessary components eliminates the exposure problem while maintaining mechanical support.
Solution Approach 2:
The patent uses a composite structure where the insulating resin layer combines multiple functions: electrical insulation, mechanical support for leads, and oxidation protection. This composite material approach integrates several protective functions into a single layer, preventing lead exposure while maintaining structural integrity.
2Object-affected harmful factors
If the lead frame eliminates support bars and section bars, then oxidation is prevented, but structural support must be provided by alternative means
Solution Approach 1:
The insulating resin layer is designed to perform multiple functions simultaneously: providing electrical insulation between leads, offering mechanical support and positioning for the leads, and protecting lead side surfaces from oxidation. This multi-functional design eliminates the need for separate support structures while maintaining all necessary functions.
3Reliability
If copper leads are used for conductivity, then electrical performance is good, but oxidation resistance is poor
Solution Approach 1:
The insulating resin layer acts as an intermediary barrier between the copper leads and the oxidizing environment. It allows the copper leads to maintain their excellent electrical conductivity while the resin layer mediates protection against oxidation by completely covering the lead side surfaces, preventing direct contact with oxygen and moisture.
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 insulating resin layer prevents oxidation of leads, improving insulation reliability and reducing wiring resistance, while the heat radiating plates and plating layers enhance thermal management and contact reliability, respectively.
Implementation Method 1
The leads 74 having the exposed side surfaces can oxidize to form copper oxide on the surfaces. Such copper oxide increases the wiring resistance of the leads.
Implementation Method 2
heat radiating plates and plating layers enhance thermal management and contact reliability
Data Source
Figure 1A~1C
Figure 2A~2D
Figure 3A~3D
AI summary
A lead frame includes a plurality of leads (10) defined by an opening (11) extending in a thickness direction. An insulating resin layer (20) fills the opening to entirely cover side surfaces (10C) of each lead and to support the leads. A first surface (10A) of each lead is exposed from a first surface (20A) of the insulating resin layer (20).