Refurbishing Sputtering Targets via Hot Pressing
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Solution Overview
Problem
The existing methods for refurbishing sputtering targets result in significant material loss and heterogeneity due to multiple processing steps and the need for sawing and milling, which are undesirable and inefficient.
Innovation Solution
A process involving chemical treatment, blasting, and hot pressing with a specially designed die to minimize material loss and achieve homogeneity by sintering fresh metal powder with the spent target, eliminating the need for sawing and milling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the spent target is pulverized by crushing or refining to mix with fresh metal powder, then homogeneity is improved, but material loss increases due to dust generation
Solution Approach 1:
The patent changes the physical state and bonding parameters by applying heat and pressure through hot pressing, transforming the mixture of spent target and fresh powder into a densely bonded homogeneous structure without requiring pulverization
Solution Approach 2:
The patent creates a composite structure by bonding fresh metal powder with the spent target material through hot pressing, forming a homogeneous refurbished target that combines both materials without material loss
2Loss of substance
If hot isostatic pressing (HIP) is used to refurbish the target, then the target is refurbished without pulverization, but sawing and milling operations are required resulting in material loss
Solution Approach 1:
The patent uses hot pressing with controlled temperature and pressure parameters to achieve complete bonding of the target, eliminating the need for subsequent cooling and separation operations required by HIP
Solution Approach 2:
The patent extracts the unnecessary intermediate steps (pulverization, mixing, sawing, milling) from the refurbishment process by directly hot pressing the spent target with fresh powder in a single integrated operation
3Ease of manufacture
If multiple processing steps are used to refurbish the target, then the target can be refurbished, but the process becomes complex and time-consuming
Solution Approach 1:
The patent merges multiple separate processing steps (cleaning, powder addition, bonding, finishing) into a single hot pressing operation that simultaneously achieves all required transformations in one continuous process
Solution Approach 2:
The patent performs preliminary preparation by placing the spent target and fresh powder in the hot press die before heating, allowing the bonding process to proceed directly without intermediate preparation steps
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 process reduces material loss and ensures a homogeneous refurbished target without the need for additional processing steps, maintaining the target's integrity and reducing waste.
Implementation Method 1
applying an axial force such that the powdered metal sinters and forms a solid state diffusion bond with the target
Implementation Method 2
removing the surface impurities by a combination of chemical treatment
Implementation Method 3
removing the surface impurities by a combination of chemical treatment followed by blasting
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
Disclosed in this specification is a process for refurbishing a spent sputtering target. The process includes the step of applying sufficient heat and axial force to the filled sputtering target to hot press the filled sputtering target such that the powdered metal fuses with the un-sputtered metal, producing a refurbished target. The process may be used to refurbish precious metal targets, such as ruthenium targets.