Interconnect Substrate Manufacturing via Displacement Plating
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Solution Overview
Problem
Existing methods for manufacturing interconnect substrates face challenges in achieving high-density, conductive, and reliable interconnects due to limitations in patterning and metal deposition processes, particularly in maintaining conductivity and preventing oxidation.
Innovation Solution
The method involves forming a catalyst layer on a substrate, followed by electroless plating with a first metal having a higher ionization tendency, and then a second metal with a lower ionization tendency, utilizing a displacement plating reaction to deposit the second metal layer, which enhances conductivity and reliability without the need for additional catalyst layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photoresist patterning method is used to form plating resist and deposit metal layers, then metal deposition can be achieved, but the process complexity increases and manufacturing precision decreases
Solution Approach 1:
The invention extracts and eliminates the photoresist patterning step from the conventional process. Instead of using photoresist to define patterns, the catalyst layer itself is formed with the desired pattern directly, serving both as the pattern definition and the plating catalyst, thereby simplifying the manufacturing process while maintaining precision
Solution Approach 2:
The catalyst layer serves multiple functions: it acts as the pattern definition, the plating catalyst, and the structural template for metal deposition. This multi-functionality eliminates the need for separate photoresist layers and reduces process steps
2Reliability
If a single metal layer is deposited, then the process is simple, but conductivity and oxidation resistance are insufficient
Solution Approach 1:
The invention uses a composite metal layer structure consisting of a first metal layer (e.g., nickel or palladium) and a second metal layer (e.g., copper). The first metal provides oxidation resistance, while the second metal provides high conductivity, creating a composite structure that delivers both reliability requirements simultaneously
Solution Approach 2:
Different regions of the metal layer structure have different compositions optimized for different functions: the first metal layer is optimized for oxidation resistance, while the second metal layer is optimized for conductivity. Each layer performs its specific function locally
3Manufacturing precision
If additional catalyst layers are added for each metal deposition step, then metal layers can be formed, but the device complexity and manufacturing steps increase
Solution Approach 1:
The patterned catalyst layer serves as a universal catalyst for both the first and second metal depositions. By forming the catalyst layer with the final desired pattern from the beginning, it can catalyze multiple metal deposition steps without requiring additional catalyst layers, thereby reducing complexity while maintaining deposition control
Solution Approach 2:
The catalyst layer is formed with the final desired pattern in advance, before any metal deposition occurs. This preliminary patterning allows subsequent metal layers to be deposited precisely where needed without requiring additional patterning or catalyst 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
This approach allows for the accurate formation of high-density interconnects with excellent conductivity and high reliability, reducing oxidation risks and simplifying the manufacturing process by eliminating the need for additional catalyst layers, while enabling precise control over interconnect formation.
Implementation Method 1
immersing the substrate in a first electroless plating solution including a first metal to deposit the first metal on the catalyst layer to form a first metal layer
Implementation Method 2
immersing the substrate in a second electroless plating solution including a second metal to deposit the second metal on the first metal layer to form a second metal layer, an ionization tendency of the first metal being higher than an ionization tendency of the second metal
Data Source
AI summary
A method of manufacturing an interconnect substrate by electroless plating, including: (a) forming a catalyst layer with a specific pattern on a substrate; (b) immersing the substrate in a first electroless plating solution including a first metal to deposit the first metal on the catalyst layer to form a first metal layer; and (c) immersing the substrate in a second electroless plating solution including a second metal to deposit the second metal on the first metal layer to form a second metal layer, an ionization tendency of the first metal being higher than an ionization tendency of the second metal.