Circuit Electrode Gold Plating Resin Adhesion
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Solution Overview
Problem
The existing semiconductor packaging technologies face challenges in ensuring intimate contact between the pad electrode and the sealing resin layer, leading to reduced reliability due to thermal stress and humidity exposure, especially in highly integrated and miniaturized electronic devices.
Innovation Solution
A circuit apparatus with a copper wiring layer and a gold plating layer, where the sealing resin layer contacts both the gold plating layer and the wiring layer, enhancing the intimacy of contact and improving reliability by minimizing surface degradation and improper connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing resin layer contacts only the gold plating layer, then the manufacturing process is simpler, but the intimacy of contact is insufficient leading to exfoliation under thermal stress and humidity
Solution Approach 1:
The patent transitions from a single-layer gold plating structure to a multi-layer electrode structure with copper wiring layer, nickel undercoat layer, and gold plating layer arranged in vertical dimension. This dimensional change allows the sealing resin layer to contact multiple layers simultaneously, enhancing intimacy of contact without complicating the horizontal layout.
Solution Approach 2:
The patent employs a composite electrode structure combining copper (high conductivity), nickel (adhesion promotion), and gold (oxidation resistance). This composite material approach creates a multi-functional electrode that provides both electrical connectivity and enhanced mechanical bonding with the sealing resin layer, preventing exfoliation under thermal stress and humidity.
2Reliability
If the electrode structure is simplified to reduce manufacturing steps, then the manufacturing cost decreases, but the resistance to thermal stress and humidity deteriorates
Solution Approach 1:
The patent optimizes the thickness parameters of each layer: copper wiring layer (3-10 μm), nickel undercoat layer (0.1-1 μm), and gold plating layer (0.05-0.5 μm). These parameter changes ensure that each layer performs its specific function while maintaining overall structural integrity and resistance to thermal stress and humidity during standard manufacturing processes.
Solution Approach 2:
The nickel undercoat layer serves as an intermediary between the copper wiring layer and the gold plating layer. It promotes adhesion between the copper and gold layers, preventing delamination under thermal stress, while also providing a suitable surface for gold plating deposition, thus facilitating the manufacturing process.
3Reliability
If the sealing resin layer contacts both the gold plating layer and the wiring layer, then the intimacy of contact is improved, but the device structure becomes more complex
Solution Approach 1:
The patent segments the electrode into distinct functional layers: copper wiring layer for electrical connectivity, nickel undercoat layer for adhesion, and gold plating layer for oxidation resistance and bonding interface. This segmentation allows the sealing resin layer to contact multiple segments (gold plating and copper wiring) simultaneously, enhancing intimacy of contact while maintaining clear functional differentiation that simplifies the overall design logic.
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 configuration significantly reduces the likelihood of exfoliation and improves the reliability of the circuit apparatus by providing more intimate contact between the sealing resin layer and the pad electrode, thereby enhancing its resistance to thermal stress and humidity.
Implementation Method 1
a gold plating layer formed on a surface of the wiring layer
Data Source
AI summary
A method for fabricating a circuit apparatus includes forming a wiring layer, a conductive layer, and a first insulating layer on the wiring substrate, removing the conductive layer in an opening of the first insulating layer so as to expose the wiring layer, forming a gold plating layer on the wiring layer, removing the first insulating layer and the conductive layer, forming a second insulating layer on the wiring substrate, the second insulating layer having an opening through which the gold plating and adjacent wiring layers are exposed, and electrically connecting a circuit element to the gold plating layer.