Cylindrical Sputtering Target Segmentation and Density Control
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Solution Overview
Problem
The manufacturing of long cylindrical sputtering targets for large glass substrates is impractical due to high costs and complexity, and cylindrical sintered compacts face challenges in achieving uniform density and mechanical strength, leading to distortion and variations in sputtering characteristics.
Innovation Solution
A cylindrical sputtering target is formed using multiple sintered compacts with a relative density of 99.7% to 99.9% and a cylindrical compact with a relative density of 54.5% to 58.0%, assembled with a space between them, and manufactured through cold isostatic pressing at pressures between 100 MPa and 200 MPa, ensuring minimal inter-individual density variance and high mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cylindrical sputtering target with length of at least 3000 mm is manufactured by integral molding, then the target has high mechanical strength and uniform density, but the manufacturing cost becomes excessively high and the process becomes impractical
Solution Approach 1:
The cylindrical sputtering target is divided into multiple cylindrical sintered compacts, each with a length of several ten millimeters to several hundred millimeters. These compacts are coupled together using coupling members to form the complete long target, making manufacturing practical while maintaining mechanical strength through proper coupling design
2Ease of manufacture
If multiple cylindrical sintered compacts are coupled together to form a long target, then manufacturing becomes practical, but the inter-individual density variance between adjacent compacts influences sputtering characteristics
Solution Approach 1:
The density of cylindrical sintered compacts is precisely controlled within the range of 99.7% to 99.9% relative density, with the inter-individual density variance between adjacent compacts kept at 0.1% or smaller. This parameter control ensures uniform sputtering characteristics across the entire target while maintaining manufacturing practicality
3Strength
If the density of cylindrical sintered compact is increased to maximum level to improve mechanical strength and film quality, then the compact achieves high density, but the binder is not easily pulled off during sintering causing distortion
Solution Approach 1:
The density of the cylindrical compact before sintering is controlled within the specific range of 54.5% to 58.0% relative density. This optimized density parameter allows the binder to be properly removed during sintering while achieving a final sintered compact density of 99.7% to 99.9%, preventing distortion and maintaining shape uniformity
4Shape
If the density of cylindrical sintered compact is increased to decrease contraction amount during sintering, then less distortion occurs, but the binder removal becomes difficult preventing desired shape formation
Solution Approach 1:
The initial compact density is optimized to 54.5% to 58.0% relative density, which provides sufficient binder removal capability during sintering. This parameter setting ensures that the binder can be effectively pulled off while controlling contraction to achieve the desired shape and final high density of 99.7% to 99.9%
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 results in a sputtering target with improved mechanical strength, reduced impurities, and stable discharge characteristics, enabling the formation of a thin film with high uniformity on large substrates, while minimizing distortion and maintaining desired shape and surface roughness.
Implementation Method 1
the cylindrical compact may be formed by cold isostatic pressing performed at a pressure of 100 MPa or higher and 200 MPa or lower
Implementation Method 2
A cylindrical sputtering target in an embodiment according to the present invention includes a cylindrical sintered compact having a relative density of 99.7% or higher and 99.9% or lower
Data Source
AI summary
A cylindrical sputtering target includes a plurality of cylindrical sintered compacts adjacent to each other while having a space therebetween. The plurality of cylindrical sintered compacts have a relative density of 99.7% or higher and 99.9% or lower. The plurality of cylindrical sintered compacts adjacent to each other have a difference therebetween in the relative density of 0.1% or smaller.