Polyimide Insulating Film Thickness for Semiconductor Bonding
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing size due to complex wiring patterns and warpage issues caused by coefficient mismatches, and reliability is compromised by peeling of insulating sheets not uniformly bonded during thermocompression processes.
Innovation Solution
A semiconductor device design using a metal conductor base and lead frames fixed with a polyimide-based organic insulating film, where the film thickness relationships ensure proper bonding and reduced size integration, eliminating the need for metal processing and enhancing reliability by thinner non-sandwiched film portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating sheets are used to fix lead frames to metal conductor base, then electrical insulation is achieved, but peeling occurs during thermocompression processes due to non-uniform bonding
Solution Approach 1:
The patent changes the material parameter from conventional insulating sheets to polyimide-based organic insulating film, which provides uniform bonding characteristics during thermocompression processes. This material parameter change ensures consistent adhesion strength across the entire bonding area, preventing peeling while maintaining electrical insulation between lead frames and metal conductor base.
2Reliability
If complex wiring patterns are used to achieve proper electrical connections, then electrical functionality is achieved, but device size increases
Solution Approach 1:
The patent merges multiple functions into the organic insulating film: it provides electrical insulation, mechanical bonding, and serves as a substrate for simplified wiring patterns. By combining these functions into a single integrated component with optimized thickness distribution, the patent reduces the overall device size while maintaining reliable electrical connections between power elements and lead frames.
3Reliability
If thicker insulating film is used throughout, then bonding reliability is improved, but device size and material usage increase
Solution Approach 1:
The patent applies local quality by creating non-uniform thickness distribution in the organic insulating film. The film is thicker at bonding portions where lead frames contact the metal conductor base to ensure reliable bonding, and thinner at non-bonding portions to reduce overall device size and material usage. This localized thickness optimization maintains bonding reliability while minimizing device dimensions.
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 solution allows for compact integration of multiple power elements with improved reliability by ensuring proper bonding and reduced peeling risks, while avoiding costly metal processing and maintaining structural integrity.
Implementation Method 1
a first lead frame and a second lead frame are fixed to a metal conductor base by an organic insulating film made of a polyimide-based material
Data Source
AI summary
In a semiconductor device, a first lead frame and a second lead frame are fixed to a metal conductor base by an organic insulating film made of a polyimide-based material. The organic insulating film satisfies relationships of tpress1>tcast1 and tpress2>tcast1, where tpress1 is a thickness of a portion of the organic insulating film sandwiched between the metal conductor base and the first lead frame, tpress2 is a thickness of a portion of the organic insulating film sandwiched between the metal conductor base and the second lead frame, and tcast1 is a thickness of a portion of the organic insulating film that is not sandwiched between the metal conductor base and the first lead frame and is not sandwiched between the metal conductor base and the second lead frame.