Multi-Block Molybdenum Sputtering Target Without Bonding Agent
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Solution Overview
Problem
There is a need for large area sputtering targets with uniform composition and microstructure, and without visible joint lines, to ensure high strength and minimize particle formation during the sputtering process, particularly for applications like flat panel displays where imperfections can impact device quality.
Innovation Solution
A sputtering target comprising consolidated blocks of molybdenum and additional alloying elements, joined without a bonding agent, and processed under specific temperature and pressure conditions to achieve a joint with no visible line and high transverse rupture strength, ensuring uniformity and strength across the target body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If powder is used between cold-isostatically pressed blocks to join them, then the target can be manufactured, but a conspicuous joint line forms that may contribute to particle formation during sputtering
Solution Approach 1:
The invention removes the powder bonding agent from the joining process. Instead of using powder between blocks, the blocks are joined through direct contact and diffusion bonding, extracting the harmful element (powder) that causes joint lines and particle formation while maintaining the manufacturing capability
Solution Approach 2:
The invention introduces a different intermediary mechanism - diffusion bonding through atomic diffusion at the interface - to replace the powder-mediated joining. This creates a bond without leaving residual powder that would form visible joint lines and particles during sputtering
2Area of stationary object
If large area sputtering targets are manufactured from multiple blocks, then the target size can be increased, but visible joint lines appear between blocks
Solution Approach 1:
The invention extracts the powder bonding agent that creates visible joint lines, allowing large area targets to be manufactured from multiple blocks without the cosmetic defect of conspicuous joints
Solution Approach 2:
The invention changes the bonding parameters by using diffusion bonding at elevated temperatures without powder, transforming the joint interface from a powder-filled gap to a metallurgically bonded interface that is visually indistinguishable from the bulk material
3Ease of manufacture
If traditional powder-based joining is used, then blocks can be connected, but the joint strength and uniformity are compromised
Solution Approach 1:
The invention uses atomic diffusion as the intermediary mechanism to create bonds between blocks, replacing the powder-based mechanical interlocking with a metallurgical diffusion bond that provides superior strength and uniformity
Solution Approach 2:
The invention changes the joining parameters by applying heat and pressure to enable diffusion bonding, transforming the connection from a weak powder-based joint to a strong metallurgical bond with enhanced strength and uniformity
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 solution provides sputtering targets with enhanced uniformity, reduced particle formation, and high mechanical properties, enabling the production of high-quality thin films for electronic devices without the drawbacks of traditional targets with powder joints.
Implementation Method 1
Sputtering processes typically involve bombarding a solid sputtering target with energized particles to eject atoms from the target
Implementation Method 2
a joint between the at least two consolidated blocks, the joint being free of an added bonding agent
Data Source
AI summary
A sputtering target that includes at least two consolidated blocks, each block including an alloy including molybdenum in an amount greater than about 30 percent by weight and at least one additional alloying ingredient; and a joint between the at least two consolidated blocks, the joint being free of any microstructure due to an added bonding agent (e.g., powder, foil or otherwise), and being essentially free of any visible joint line the target that is greater than about 200 μm width (e.g., less than about 50 μm width). A process for making the target includes hot isostatically pressing, below a temperature of 1080° C., consolidated perform blocks that may be surface prepared (e.g., roughened to a predetermined roughness value) prior to pressing.