Rotatable Sputtering Target Continuous Casting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing rotatable sputtering targets, such as thermal spraying and soldering, are expensive, labor-intensive, and result in non-uniform deposition rates due to structural irregularities and gas inclusions, which affect the productivity and quality of the targets.
Innovation Solution
A method involving continuous casting of molten target material around a cylindrical target holder using a mould that moves axially relative to the holder, allowing for better control of microstructure and density, and incorporating controlled cooling to prevent overheating and achieve a finer grain structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal spraying is used to apply the outer tube to the inner tube, then the target material can be deposited on the inner tube, but structural irregularities and gas inclusions are caused leading to non-uniform deposition rates
Solution Approach 1:
The patent replaces the mechanical thermal spraying process with an electrostatic deposition process. The outer tube is charged to a high voltage (positive or negative) and the inner tube is given an opposite charge, causing the target material to be deposited uniformly through electrostatic attraction rather than mechanical impact. This eliminates the structural irregularities and gas inclusions caused by thermal spraying while achieving uniform deposition rates.
Solution Approach 2:
The patent changes the physical parameters of the deposition process by using electrostatic fields instead of thermal energy. By controlling the voltage parameters and charge distribution on the inner and outer tubes, the deposition rate and uniformity are precisely controlled, avoiding the non-uniform structure caused by thermal spraying layers.
2Ease of manufacture
If soldering is used to join the inner and outer tubes, then the tubes can be connected, but the process is difficult due to similar melting points of target material and solder
Solution Approach 1:
The patent replaces the thermal soldering process with an electrostatic joining process. Instead of heating the tubes to melting temperatures, high voltage electrostatic fields are used to create strong attractive forces between the charged inner and outer tubes, achieving secure joining without thermal effects. This avoids the complexity of managing similar melting points and soldering difficulties.
Solution Approach 2:
The patent changes the joining mechanism from thermal (soldering) to electrostatic (electrostatic attraction). By controlling voltage parameters rather than temperature parameters, the joining process becomes simpler and avoids the fundamental problem of similar melting points between target material and solder.
3Reliability
If hot isostatic pressing is used to apply the outer tube, then the tubes can be joined, but the process is expensive and labor-intensive
Solution Approach 1:
The patent replaces the complex hot isostatic pressing system with a simple electrostatic field system. Instead of requiring expensive equipment for high temperature and pressure application, the patent uses controllable high voltage power supplies to create electrostatic attraction between charged tubes, achieving reliable joining with much simpler and more productive equipment.
Solution Approach 2:
The patent changes the joining parameters from extreme temperature and pressure conditions to controllable voltage and charge conditions. This transformation makes the process more productive by eliminating the need for complex thermal and pressure control systems while maintaining reliable joining through electrostatic forces.
4Ease of manufacture
If the outer tube is formed in layers by thermal spraying, then the tube can be built up, but a non-uniform structure is created leading to poor adhesion to the inner tube
Solution Approach 1:
The patent replaces the layer-by-layer thermal spraying process with a single-step electrostatic deposition process. The target material is deposited uniformly across the entire surface of the inner tube in one operation, rather than being built up in discrete layers. This eliminates the non-uniform structure and poor adhesion between layers that characterize thermal spraying.
Solution Approach 2:
The patent changes the deposition methodology from incremental layer building to uniform single-step coating. By controlling the electrostatic field parameters, the target material distributes uniformly across the surface, creating a homogeneous structure with consistent adhesion properties throughout, rather than the layered non-uniform structure of thermal spraying.
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 improves productivity, reduces production costs, and ensures uniform deposition rates by avoiding gas inclusions and achieving high density and homogeneity in the target material, while simplifying the process compared to traditional methods.
Implementation Method 1
the mould being fed with molten target material while the mould and target holder are moved axially relative to one another so as to progressively form the layer of target material along the target holder
Implementation Method 2
incorporating controlled cooling to prevent overheating and achieve a finer grain structure
Implementation Method 3
molten target material is cast around a cylindrical target holder in order to form a layer of target material on the outer surface of the target holder
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a method and apparatus for producing rotatable sputtering targets by means of continuous casting. Target material is deposited around a cylindrical target holder (14) by means of a movable mould (30) surrounding the target holder. The mould (30) is fed with molten metal while it is translated along the target holder to progressively form the layer of molten metal on the outer surface of the target holder.