Memory Card PCB Plating for Unified Terminal and Mounting Surfaces
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Solution Overview
Problem
The existing process for fabricating printed circuit boards for memory cards requires separate gold plating steps for terminal and mounting parts, leading to increased economic and productivity costs due to the need for multiple processes such as exposure and development, and differing material properties.
Innovation Solution
A surface treatment method using a nickel metal layer with added primary and secondary brighteners, followed by palladium and gold plating, is applied simultaneously to both terminal and mounting parts, reducing the gold plating thickness while ensuring hardness and wire bonding properties, and optimizing the brightener ratio to prevent abnormal nickel spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate gold plating steps are performed for terminal part and mounting part, then the required surface properties (hardness for terminal, wire bonding for mounting) are achieved, but the fabrication process complexity and cost increase
Solution Approach 1:
The patent combines the previously separate gold plating processes for terminal parts and mounting parts into a single simultaneous plating step. By using a unified plating bath containing specific additives (hardness agents and wire bonding agents), the method achieves both hardness requirements for terminal parts and wire bonding requirements for mounting parts in one operation, thereby reducing process complexity while maintaining surface property requirements
Solution Approach 2:
The plating bath is designed to serve multiple functions simultaneously: it provides gold deposition, imparts hardness to terminal parts, and ensures wire bonding capability for mounting parts. This multi-functional plating solution eliminates the need for separate specialized plating steps for different parts, simplifying the overall fabrication process
2Reliability
If multiple plating processes are used for terminal and mounting parts, then the required material properties are achieved, but the fabrication time and productivity decrease
Solution Approach 1:
The patent merges multiple sequential plating operations into a single concurrent plating process. By formulating a unified plating bath that contains additives for both hardness and wire bonding properties, the method enables simultaneous treatment of terminal parts and mounting parts, thereby reducing total fabrication time while maintaining required material properties
Solution Approach 2:
The plating process operates continuously to deposit gold while simultaneously imparting both hardness and wire bonding properties. The unified plating bath allows all necessary surface modifications to occur in one continuous operation rather than through multiple discrete steps, improving fabrication efficiency
3Reliability
If different plating conditions are applied to terminal and mounting parts, then the specific surface requirements are met, but the fabrication cost increases
Solution Approach 1:
The patent consolidates separate plating operations into a single unified process using one plating bath that serves both terminal parts and mounting parts. This approach eliminates the need for multiple specialized plating baths and reduces the number of process steps, thereby lowering fabrication costs while still meeting the distinct surface treatment requirements for different parts through carefully selected plating bath additives
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 method simplifies the fabrication process, reduces costs by allowing simultaneous plating of terminal and mounting parts, and enhances soldering, wire bonding, and wear resistance properties, while maintaining the required material properties.
Implementation Method 1
a nickel metal layer formed of a nickel plating solution
Implementation Method 2
a palladium metal layer formed on the nickel metal layer
Implementation Method 3
a gold metal layer formed on the palladium metal layer
Data Source
Figure 1~2c
Figure 2d~2g
Figure 2h~5
AI summary
A printed circuit board for a memory card according to the embodiment includes an insulating layer; a mounting part on a first surface of the insulating layer, the mounting part being electrically connected to a memory device; and a terminal part on a second surface of the insulating layer, the terminal part being electrically connected to an external electronic appliance, wherein a same metal layer having a same property is formed on surfaces of the mounting part and the terminal part.