Circuit Board Etching with Segmented Conductive Layers
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Solution Overview
Problem
The existing methods for etching conductive layers on circuit boards, particularly those with gold, nickel, and copper, face challenges such as impurity generation, overetching, and underetching, which affect the quality of the circuit board.
Innovation Solution
A method involving the formation of pad and lead line portions on an insulating substrate, followed by the creation of a conductive layer with a gold surface, using an etching mask to expose specific portions for etching with acid solutions like nitric acid, sulfuric acid, or iodine-potassium iodide, and subsequent OSP treatment to improve etching precision and prevent copper extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used on multi-metal conductive layers, then etching can be performed, but impurities are generated and etching precision deteriorates
Solution Approach 1:
The conductive layer is segmented into distinct metal layers (first conductive layer with copper, second conductive layer with gold) with different etching characteristics. This allows selective etching of each layer using optimized etching solutions, preventing impurity generation from attempting to etch multiple metals simultaneously with a single solution.
Solution Approach 2:
Different etching parameters are applied to different metal layers: the first conductive layer is etched using copper chloride or iron chloride solution with controlled concentration and temperature, while the second conductive layer is etched using iodine-potassium iodide solution. This parameter optimization for each layer improves etching precision and reduces impurity generation.
2Productivity
If strong etching solutions are used to etch copper, then etching speed increases, but copper extraction and quality deterioration occur
Solution Approach 1:
The etching solution parameters are precisely controlled: copper chloride or iron chloride solution is used with concentration maintained between 5-20% and temperature between 20-40°C. This optimized parameter range achieves sufficient etching speed while preventing copper extraction and maintaining circuit board quality.
Solution Approach 2:
The etching process includes monitoring and control mechanisms to detect when etching is complete, allowing及时调整 of etching conditions to prevent over-etching and copper extraction, thereby maintaining reliability while achieving productivity.
3Reliability
If electroplating is used to form conductive layers, then conductivity and metal deposition are improved, but etching difficulty increases due to multi-layer structure
Solution Approach 1:
The conductive layer structure is segmented into distinct electroplated layers (copper layer and gold layer) with different thicknesses and properties. This segmentation allows each layer to be etched separately with optimized solutions, making the overall etching process easier despite the multi-layer structure created by electroplating.
Solution Approach 2:
The patent introduces specific etching solutions as intermediaries that selectively interact with each metal layer: copper chloride or iron chloride solution mediates the etching of the copper layer, while iodine-potassium iodide solution mediates the etching of the gold layer, simplifying the overall manufacturing process.
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 allows for precise and controlled etching of conductive layers, minimizing irregularities and preventing copper extraction, thus enhancing the quality and reliability of the circuit board.
Implementation Method 1
etching a portion of the lead line portion exposed by the etching mask and a portion of the conductive layer corresponding to the lead line portion using an etching solution containing an acid
Implementation Method 2
performing an OSP treatment on the first pad portion
Implementation Method 3
The conductive layer may be formed by electroplating
Data Source
AI summary
Provided are a circuit board and a method of manufacturing the same. The method includes: forming a pad portion and a lead line portion of a metal on an insulating substrate, wherein the lead line portion is connected to the pad portion; forming a conductive layer on the pad portion and the lead line portion, wherein the conductive layer has an upper surface comprising gold; forming an etching mask on the conductive layer so as to expose a portion corresponding to the lead line portion in the conductive layer; etching a portion of the lead line portion exposed by the etching mask and a portion of the conductive layer corresponding to the lead line portion using an etching solution containing an acid; and removing the etching mask.