Aluminum Electrode Recess Structure for Heat-Dissipating Copper Film
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Solution Overview
Problem
The existing semiconductor device has limitations in heat radiation from the aluminum electrode due to the use of a resin-based sealing member, which also fails to effectively prevent copper diffusion into the passivation film.
Innovation Solution
A semiconductor device design where the copper film is disposed in a recess on the aluminum electrode's surface, avoiding contact with the passivation film and enhancing heat radiation while suppressing copper diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the copper film is disposed close to the passivation film to improve heat radiation, then heat radiation from the aluminum electrode is improved, but copper diffuses into the passivation film deteriorating its reliability
Solution Approach 1:
The invention transitions from a planar two-dimensional layout to a three-dimensional structure by forming a recess in the aluminum electrode and placing the copper film within this recess. This vertical dimensionality change allows the copper film to be positioned close to the passivation film for improved heat radiation while the recess walls provide physical separation to prevent copper diffusion into the passivation film.
Solution Approach 2:
The copper film is nested within the recess formed in the aluminum electrode. This nesting structure allows the copper film to be embedded in a cavity that provides both thermal contact with the aluminum electrode for heat radiation and physical containment to prevent copper diffusion toward the passivation film.
2Reliability
If the copper film is separated from the passivation film to prevent copper diffusion, then polyimide film reliability is maintained, but heat radiation from the aluminum electrode is insufficient
Solution Approach 1:
Instead of horizontal separation that compromises heat radiation, the invention uses vertical separation through a recess structure. The copper film is positioned in a lower dimension (within the recess) while maintaining close proximity to the passivation film in the horizontal plane, thus achieving both diffusion prevention and effective heat radiation.
Solution Approach 2:
The recess structure creates different local environments: the recess interior provides a confined space that prevents copper diffusion while the top surface of the recess maintains thermal contact with the passivation film for heat radiation. This local quality differentiation resolves the contradiction between diffusion prevention and heat dissipation.
3Reliability
If a resin-based sealing member is used to prevent copper diffusion, then copper diffusion is blocked, but heat radiation from the aluminum electrode is hindered
Solution Approach 1:
The invention extracts and eliminates the resin-based sealing member from the structure. Instead of using a separate sealing component that would impede heat radiation, the recess structure itself provides the diffusion barrier function, allowing direct thermal contact between the copper film and passivation film without compromising reliability.
Solution Approach 2:
The recess structure serves multiple functions simultaneously: it acts as a physical barrier to prevent copper diffusion, provides thermal contact between the copper film and passivation film for heat radiation, and eliminates the need for separate sealing materials. This multi-functionality resolves the trade-off between diffusion prevention and heat dissipation.
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
This design improves heat radiation from the aluminum electrode while preventing copper diffusion into the passivation film, reducing thermal stress and maintaining the integrity of the polyimide film.
Implementation Method 1
When copper in the copper film is diffused into the polyimide film, reliability of the polyimide film is deteriorated. Therefore, in the semiconductor device described in PTL 1, the diffusion of copper into the polyimide film is prevented by disposing the copper film at a position separated from the polyimide film.
Implementation Method 2
heat radiation from the aluminum electrode
Data Source
AI summary
A semiconductor device of the present disclosure includes: a semiconductor substrate having a first main surface; a first aluminum electrode having a first surface facing the first main surface and a second surface opposite to the first surface, the first aluminum electrode being disposed on the semiconductor substrate; a passivation film that covers a peripheral edge of the second surface and that is provided with an opening from which a portion of the second surface is exposed; and a copper film. The second surface exposed from the opening is provided with a recess that is depressed toward the first surface. The copper film is disposed in the recess.