I-Shaped Lead Frame Structure to Reduce Delamination Cracking
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Solution Overview
Problem
Traditional subtractive etching processing for lead frames in semiconductor packaging often results in delamination and cracking due to lack of control in material surface oxidation and abnormal plastic packaging parameters, affecting product yield and quality.
Innovation Solution
A method involving the application of plating resistant layers, radio frequency plasma processing, and dielectric barrier discharge plasma processing to create a capping structure on the lead frame, enhancing bonding with the plastic packaging body and reducing stress through increased surface roughness and hydrophilicity, forming an I-shape structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional subtractive etching processing is used to form the lead frame structure, then the manufacturing process is simple, but the contact surface is prone to delamination and cracking under stress
Solution Approach 1:
The patent inverts the traditional subtractive etching approach by using an additive manufacturing approach. Instead of removing material to create the lead frame structure, the patent builds the structure layer by layer using electroplating, chemical vapor deposition, or sputtering techniques. This inversion allows for creating a three-dimensional I-shaped contact surface structure that enhances bonding strength while maintaining manufacturing feasibility through controlled deposition processes
Solution Approach 2:
The patent transitions from a traditional two-dimensional planar contact surface to a three-dimensional I-shaped structure. By adding vertical dimensionality to the contact surface, the patent increases the bonding area and creates a more robust mechanical interlock between the lead frame and plastic packaging body, thereby improving reliability without significantly complicating the manufacturing process
2Device complexity
If the lead frame contact surface is designed with traditional geometry, then the structure is simple, but delamination and cracking occur under stress
Solution Approach 1:
The patent introduces a three-dimensional I-shaped geometry to the contact surface, adding vertical height and depth dimensions to the traditional flat surface. This dimensional enhancement creates a mechanical interlock effect that significantly improves bonding strength and stress distribution, preventing delamination and cracking while maintaining reasonable structural complexity
Solution Approach 2:
The I-shaped contact surface structure can be viewed as a nested configuration where the vertical portions of the I-shape create interlocking features between the lead frame and packaging body. The structure embeds itself into the packaging material, creating a nested relationship that enhances mechanical bonding and distributes stress more effectively
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 method strengthens the bonding force between the lead frame and plastic packaging body, reducing delamination and cracking, and enhances product structural strength and reliability, particularly in varying environments.
Implementation Method 1
treating the inner wall of the opening of the first recess using radio frequency plasma processing to increase its roughness
Implementation Method 2
using dielectric barrier discharge (DBD) plasma processing to improve surface tension and hydrophilicity of the inner wall of the opening of the second recess
Implementation Method 3
filling the first recess by electroplating, chemical deposition or sputtering to obtain a first protruding platform
Implementation Method 4
filling the first recess by electroplating, chemical deposition or sputtering to obtain a first protruding platform
Implementation Method 5
filling the first recess by electroplating, chemical deposition or sputtering to obtain a first protruding platform
Data Source
AI summary
The present invention discloses a method for manufacturing a lead frame, comprising providing a first plating resistant layer on the surface of a frame substrate, providing a first recess on the first plating resistant layer, filling the first recess to obtain a first protruding platform, providing a second plating resistant layer on the first protruding platform and the first plating resistant layer, providing a second recess on the second plating resistant layer, filling the second recess, providing a capping structure on the first protruding platform; the capping structure, first protruding platform, and frame substrate form an I-shape structure, which reduces the probability of delamination and cracking.