Oriented Copper Plate with Cr Precipitates for Flexible Circuit Boards
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Solution Overview
Problem
Conventional copper materials with advanced cube textures face challenges in achieving both high strength and breaking elongation, particularly when stress is applied in specific orientations, limiting their fatigue characteristics and flexibility, especially in applications like flexible circuit boards and solar cell connections.
Innovation Solution
An oriented copper plate with a highly developed cube texture and Cr precipitation is developed, featuring a specific texture density and Cr concentration that enhances strength and breaking elongation, allowing for improved flexibility and durability against thermal cycles and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-density cube texture is formed in copper material, then fatigue characteristics are improved and breaking elongation is enhanced, but strength is reduced
Solution Approach 1:
The patent creates a composite microstructure within the copper material by combining cube-oriented grains with specific precipitates or secondary phases. This composite structure allows the material to simultaneously achieve high strength from the precipitate reinforcement and improved fatigue characteristics from the cube texture, resolving the contradiction between strength and fatigue resistance
Solution Approach 2:
The patent applies local quality by creating regions with different microstructural characteristics within the copper material. Specifically, it controls the distribution of precipitates or secondary phases in relation to the cube-oriented grain structure, allowing different local regions to contribute differently to overall strength and fatigue performance
2Strength
If alloy elements are added to improve strength through solid solution or precipitation, then strength increases, but cube texture formation is inhibited
Solution Approach 1:
The patent employs parameter changes by carefully controlling the concentration ranges of alloying elements and adjusting processing parameters such as rolling reduction rates and heat treatment temperatures. These parameter optimizations allow the material to achieve both desired strength improvements and maintenance of cube texture, overcoming the inhibitory effect of alloying on texture formation
Solution Approach 2:
The patent applies preliminary action by performing specific preprocessing steps before final cube texture development. This may include preliminary rolling, intermediate heat treatments, or controlled alloying element distribution that prepares the microstructure for subsequent cube texture formation while still achieving strength enhancement through precipitate formation
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 oriented copper plate exhibits superior strength, breaking elongation, and folding flexibility, making it suitable for various applications, including flexible circuit boards and solar cell wiring, with enhanced resistance to fatigue and thermal cycles.
Implementation Method 1
an oriented copper plate having features of material texture regarding both advanced cube texture and Cr precipitation
Implementation Method 2
A {100} texture has a stable recrystallization orientation of relatively high purity copper, which is texture orientation that is relatively easy to develop
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
According to this invention, an oriented copper plate which has a highly developed cube texture and has strength and breaking elongation greater than those of a conventional material having a cube texture, a copper-clad laminate, a flexible circuit board that is excellent in terms of folding flexibility, and an electronic device are provided, and a process for producing the oriented copper plate is established. This invention relates: an oriented copper plate, which contains 0.03% by mass to 1.0% by mass of Cr, the remainder of which is composed of copper and inevitable impurities, wherein the copper plate has a <100> main orientation so that the area percentage of a <100> preferred orientation region is not less than 60.0%, the region satisfying a condition that allows each of a thickness direction of the copper plate and a specific in-plane direction of the copper plate to have an orientation difference of not more than 15° with respect to a <100> basic copper crystal axis of unit lattice of copper, and wherein Cr precipitates having equivalent circle diameters of 4 nm to 52 nm are present at 300 precipitates/µm3 to 12000 precipitates/µm3; a copper-clad laminate and a flexible circuit board using the copper plate; and an electronic devices equipped with the flexible circuit board.