Semiconductor Reactant Layer Prevents Substrate Contamination
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Solution Overview
Problem
The existing technologies for manufacturing semiconductor devices with nickel films face challenges such as contamination of the semiconductor substrate, warping of the device, and defects in solder bonding due to the use of zincate treatment and thick nickel films, which affect the adhesion and quality of the nickel plating.
Innovation Solution
A semiconductor device configuration that includes a reactant layer containing metal of the catalyst metal film between the aluminum alloy film and the catalyst metal film, which prevents contamination and allows for the deposition of an electroless nickel plating film without zincate treatment, enhancing adhesion and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If zincate treatment is performed to deposit electroless Ni plating on Al alloy electrode surface, then Ni plating can be formed, but the Al alloy electrode is locally anomalously etched and disappears causing substrate contamination
Solution Approach 1:
A reactant layer containing metal of the catalyst metal film is introduced as an intermediary between the Al alloy electrode and the chemical solutions. This reactant layer acts as a protective barrier that prevents direct contact between the Al alloy electrode and the etching chemicals, thereby preventing local anomalous etching and substrate contamination while still allowing electroless Ni plating to proceed on the catalyst metal film surface.
Solution Approach 2:
The catalyst metal film is deposited on the Al alloy electrode surface before the electroless Ni plating process. This preliminary deposition creates a protective layer that prevents the subsequent chemical treatments from directly attacking the Al alloy electrode, thus preventing contamination while enabling Ni plating formation.
2Reliability
If Ni film thickness is increased to 2 μm or larger to prevent erosion by solder, then solder bonding performance improves, but manufacturing cost increases and patterning becomes difficult
Solution Approach 1:
The patent replaces the conventional evaporation coating or sputtering deposition methods with electroless plating. This substitution enables cost-effective formation of thick Ni films (2 μm or larger) with excellent patternability, as electroless plating can be applied to complex geometries and achieves uniform thick deposits that are difficult to obtain with physical vapor deposition methods.
3Reliability
If Ni film thickness is increased to prevent erosion by solder, then solder bonding performance improves, but warping of semiconductor device increases making handling difficult
Solution Approach 1:
The patent employs a composite electrode structure consisting of multiple layers: Al alloy electrode, reactant layer, catalyst metal film, and electroless Ni plating. This composite structure distributes stress and prevents excessive warping while achieving the required Ni film thickness (2 μm or larger) for erosion resistance. The multi-layer construction allows the thick Ni film to be formed without causing severe warping that would compromise device handling.
4Productivity
If activation process is performed without pretreatment to deposit electroless Ni plating, then process steps are reduced, but stable quality cannot be maintained resulting in adhesion defects
Solution Approach 1:
The catalyst metal film is deposited on the Al alloy electrode surface before the electroless Ni plating process, serving as a preliminary preparation that eliminates the need for separate pretreatment steps like degreasing, pickling, and zincate treatment. This preliminary action maintains stable adhesion quality while improving process efficiency by reducing the number of process steps.
Solution Approach 2:
The reactant layer containing catalyst metal film acts as an intermediary that provides a stable surface for Ni plating deposition without requiring aggressive pretreatment. This intermediary layer enables direct transition from electrode preparation to Ni plating while maintaining consistent adhesion quality, thus improving productivity without sacrificing manufacturing precision.
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 reactant layer effectively reduces contamination and ensures stable adhesion between the nickel plating film and the semiconductor substrate, improving the yield and quality of the semiconductor device by preventing loss of the aluminum alloy film and maintaining uniform film thickness.
Implementation Method 1
a catalyst metal film disposed above the aluminum alloy film and exhibiting catalytic activity for autocatalytic reaction that deposits nickel
Implementation Method 2
exhibiting catalytic activity for autocatalytic reaction that deposits nickel
Implementation Method 3
a reactant layer disposed between the aluminum alloy film and the catalyst metal film and containing metal of the catalyst metal film... the reactant layer reduces contamination of a semiconductor substrate with, for example, a degreasing solution, an electroless Ni plating solution
Implementation Method 4
an electroless nickel plating film disposed on the catalyst metal film
Implementation Method 5
exhibiting catalytic activity for autocatalytic reaction that deposits nickel
Data Source
AI summary
A technology capable of reducing contamination of a semiconductor substrate above which a nickel film is disposed is provided. A semiconductor device includes: a semiconductor substrate; an aluminum alloy film disposed on at least one of a front surface and a back surface of the semiconductor substrate; a catalyst metal film disposed above the aluminum alloy film and exhibiting catalytic activity for autocatalytic reaction that deposits nickel; an electroless nickel plating film disposed on the catalyst metal film; and a reactant layer disposed between the aluminum alloy film and the catalyst metal film and containing metal of the catalyst metal film.