Plating Configuration for Metal-Diamond Composite Substrates
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Solution Overview
Problem
Metal-diamond composites substrates face challenges with brittle electroless nickel plating, which cracks under temperature cycles and fails in corrosive environments due to coefficient of thermal expansion mismatch, necessitating a more robust and cost-effective plating solution.
Innovation Solution
A substrate with a plating configuration comprising a copper, silver, or gold plating seed layer, a nickel-based plating barrier layer, and an optional gold or silver plating adhesion layer, applied using electroless or electrolytic plating, to provide a ductile and environmentally robust coating for metal-diamond composite substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless nickel plating is used to protect sidewalls of metal-diamond composite substrates, then corrosion and wear protection is achieved, but the plating becomes brittle and cracks during temperature cycling due to CTE mismatch
Solution Approach 1:
The plating is divided into multiple functional layers: an electroless nickel layer for corrosion protection, a electroplated copper layer for ductility and CTE matching, and an optional electroless nickel-phosphorus layer for enhanced corrosion resistance. This segmentation allows each layer to perform its specific function without the limitations of a single-material plating system.
Solution Approach 2:
The patent creates a composite plating structure combining different materials (nickel, copper, nickel-phosphorus) with complementary properties. The electroplated copper layer provides ductility and CTE matching to prevent cracking, while the electroless nickel layers provide corrosion protection, achieving a synergistic effect that overcomes the limitations of conventional single-layer electroless nickel plating.
2Object-affected harmful factors
If electroless nickel plating is applied to sidewalls, then corrosion protection is provided, but the plating fails in corrosive environments such as salt fog due to brittleness and CTE mismatch
Solution Approach 1:
The electroplated copper layer is applied first to establish a ductile, CTE-matched foundation that prevents cracking during temperature cycling. This preliminary action creates a stable base that maintains structural integrity before the final corrosion-resistant nickel-phosphorus layer is applied, ensuring the plating system can withstand environmental stressors.
Solution Approach 2:
The patent changes the material parameters of the plating system by introducing electroplated copper with CTE closely matching the metal-diamond composite substrate. This parameter change (CTE matching) prevents thermal stress accumulation during temperature cycling, while the electroless nickel-phosphorus layer maintains corrosion resistance, thereby improving environmental durability.
3Reliability
If conventional electroless nickel plating is used, then a protective coating is achieved, but the plating is relatively costly and requires complex processing
Solution Approach 1:
The electroplated copper layer serves multiple functions: it provides ductility to prevent cracking, matches the CTE of the substrate to reduce thermal stress, and acts as an adhesive intermediate layer between the electroless nickel layers and the substrate. This multi-functionality reduces the need for additional specialized layers and simplifies the overall manufacturing process.
Solution Approach 2:
The patent replaces the conventional single-step electroless nickel plating process with a multi-step process involving electroless nickel, electroplated copper, and electroless nickel-phosphorus. This substitution uses different plating mechanisms (electroless vs. electroplating) to achieve superior performance, where electroplating the copper layer allows for better control of thickness and properties, ultimately reducing manufacturing complexity and cost despite the additional steps.
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 proposed plating configuration enhances the durability and thermal conductivity of metal-diamond composite substrates, preventing cracking and failure in temperature cycles and corrosive environments, while maintaining low costs and using easily attainable materials.
Implementation Method 1
electroless plating is the only option for protecting these sidewalls
Implementation Method 2
applied using electroless or electrolytic plating
Implementation Method 3
the heat produced by the semiconductor dies could be conducted away from their immediate vicinity through the bulk substrate
Data Source
AI summary
The present disclosure relates to a substrate with a plating configuration and a process for making the same. The disclosed substrate includes a substrate base with a substrate body, and a plating configuration with a plating seed layer and a plating barrier layer. Herein, the substrate body is formed of metal-diamond composites. The plating seed layer is formed of copper, silver, or gold, and the plating barrier layer includes nickel material. The plating seed layer directly covers at least sidewalls of the substrate body, and the plating barrier layer is directly formed over the plating seed layer and encloses the substrate base.