Cu-Ni-Si Copper Alloy Sheet for Narrow-Pitch Etching Accuracy
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Solution Overview
Problem
Existing Cu-Ni-Si-based copper alloy sheet materials fail to provide sufficient etching accuracy for semiconductor packages with narrow pitches due to excessive etching in the width direction of slits, leading to diminished dimensional accuracy.
Innovation Solution
A Cu-Ni-Si-based copper alloy sheet material with controlled crystal orientations and lattice strain, produced through specific processing steps including solution treatment, cold rolling, and low-temperature annealing in a hydrogen-inert gas atmosphere, to enhance etching factor by minimizing width-direction etching while maintaining depth-direction etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional Cu-Ni-Si-based copper alloy sheet materials are used for etching, then the etching process can be performed, but excessive etching occurs in the width direction of slits leading to poor dimensional accuracy
Solution Approach 1:
The invention changes the material parameters by controlling crystal orientation (Brass orientation area ratio of 70% or more) and lattice strain (KAM value of 1.5° or more) through specific heat treatment processes, which fundamentally alters the etching behavior to suppress width-direction etching while maintaining depth-direction etching
Solution Approach 2:
The invention uses a hydrogen-inert gas mixed atmosphere during low-temperature heat treatment to create a controlled environment that enables precise control of crystal orientation and lattice strain, which in turn controls the etching factor to achieve high etching accuracy
2Productivity
If the pin distance is reduced to achieve narrow pitch, then the component density increases, but the etching accuracy deteriorates due to excessive width-direction etching
Solution Approach 1:
By changing the material parameters (crystal orientation to Brass orientation dominant, KAM value of 1.5° or more), the invention enables precise etching even at narrow pitches with pin distances of 300 μm or less, allowing higher component density without sacrificing accuracy
3Reliability
If existing heat treatment processes are applied, then the strength and conductivity are maintained, but the etching factor is not sufficiently improved
Solution Approach 1:
The invention optimizes the heat treatment parameters (low-temperature range of 200-450°C, hydrogen-inert gas atmosphere, specific holding times) to simultaneously achieve Brass orientation dominant crystal structure, adequate lattice strain (KAM ≥ 1.5°), and etched surface smoothness, while maintaining the inherent strength and conductivity balance of Cu-Ni-Si-based alloys
Solution Approach 2:
The invention creates a composite microstructure with Brass orientation dominant crystal grains and controlled lattice strain, which combines the benefits of good etching performance with maintained mechanical properties and electrical conductivity
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 material achieves a high etching factor, ensuring precise etching with narrow pitches, enhancing dimensional accuracy and maintaining strength, conductivity, and bending workability for current-carrying components.
Implementation Method 1
a solution treatment
Implementation Method 2
an aging treatment
Implementation Method 3
low temperature annealing
Data Source
Figure 1~3
Figure 4
AI summary
To provide a copper alloy sheet material having etching characteristics that are advantageous for providing a high dimensional accuracy in etching with an extremely narrow pitch, having a chemical composition containing, in terms of percentage by mass, Ni: 1.00 to 4.50%, Si: 0.10 to 1.40%, and depending on necessity one or more kind of Co, Mg, Cr, P, B, Mn, Sn, Ti, Zr, Al, Fe, Zn, and Ag, having an area ratio SB/SS of 0.40 or more in an EBSD measurement on a cross section perpendicular to a rolling direction, wherein Ss represents an area of a region satisfying at least one of conditions of a crystal orientation difference from the S1 {241} <112> orientation of 10° or less and a crystal orientation difference from the S2 {231} <124> orientation of 10° or less, and SB represents an area of a region having a crystal orientation difference from the Brass {011} <211> orientation of 10° or less.