CuMn Sputtering Target Composition With Late-Addition Carbon Gettering
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Solution Overview
Problem
The existing vacuum induction melting (VIM) processes for producing copper-manganese (CuMn) sputtering targets suffer from carbon-based defects due to reactions with graphite crucibles, leading to Mn-based carbide compounds and homogeneous nucleation, which increase defectivity and affect the adhesion of CuMn seed layers in semiconductor integrated systems.
Innovation Solution
A method involving a Programmable Logic Controller (PLC) controlled vacuum induction melting process that adds manganese and active elements, such as oxygen, iron, sulfur, hydrogen, and chromium, as a late addition into the stirring wakes of the molten copper, forming evaporable gaseous forms of COx to act as carbon getters, thereby reducing defects by preventing contact with the crucible walls and homogenizing the alloy for improved purity and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional vacuum induction melting process is used to produce CuMn sputtering target, then the production process is simple and efficient, but carbon-based defects are generated due to reactions with graphite crucibles
Solution Approach 1:
The harmful carbon source (graphite crucible) is removed from the system by using a water-cooled copper crucible instead, which prevents carbon contamination during the melting process. This extraction of the harmful element directly addresses the defect generation problem while maintaining production efficiency.
Solution Approach 2:
A water-cooled copper crucible is introduced as an intermediary container to replace the traditional graphite crucible. This intermediary prevents direct contact between the molten CuMn alloy and carbon sources, thereby eliminating carbon-based defect formation while allowing the melting process to continue efficiently.
2Stability of the object's composition
If manganese is added early in the melting process, then the alloying is thorough, but Mn-based carbide compounds form due to contact with crucible walls
Solution Approach 1:
The carbon source (graphite crucible) is removed from the system, preventing the formation of Mn-based carbide compounds that would otherwise occur during thorough alloying. This allows complete mixing without the harmful side reaction.
Solution Approach 2:
The crucible material and temperature control parameters are changed by using a water-cooled copper crucible with controlled wall temperature. This parameter change prevents carbide formation while still allowing thorough alloy homogenization through controlled melting and stirring.
3Reliability
If high purity copper and controlled alloy addition are used, then the sputtering target purity is improved, but the process complexity increases
Solution Approach 1:
The water-cooled copper crucible serves as an intermediary that inherently prevents carbon contamination, eliminating the need for complex post-processing purification steps. The crucible itself becomes the purification mechanism, simplifying the overall process while ensuring high purity.
Solution Approach 2:
The use of a composite cooling system (water-cooled copper crucible) combines the high thermal conductivity of copper with active cooling to maintain precise temperature control. This composite approach achieves high purity results through a single integrated process rather than multiple separate 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 approach results in a low carbon defect CuMn sputtering target with a manganese concentration up to 5 wt % and purity of 99.999% or higher, achieving a defect reduction of 50% or greater compared to traditional VIM processes, as evaluated by ultrasonic defect inspection, and improving the performance of sputtering targets.
Implementation Method 1
vacuum induction melting (VIM) processes for producing copper-manganese (CuMn) sputtering targets
Implementation Method 2
a method involving a Programmable Logic Controller (PLC) controlled vacuum induction melting process
Implementation Method 3
adds manganese and active elements, such as oxygen, iron, sulfur, hydrogen, and chromium, as a late addition into the stirring wakes of the molten copper
Data Source
AI summary
Provided is a low carbon defect copper-manganese (CuMn) sputtering target and systems and methods for producing the same. The low carbon defect CuMn sputtering target may comprise of copper with a purity of at least about 99.9999%, manganese with a purity of about 99.9% to about 99.999%, and one or more active elements comprising of oxygen (O) at about 100 parts per million (ppm) to about 4000 ppm, iron (Fe) at about 5 parts per billion (ppb) to about 100 ppm, sulfur (S) at about 5 ppm to about 400 ppm, hydrogen (H) at about 1 ppm to about 10 ppm, and chromium (Cr) at about 5 ppb to about 200 ppm, wherein the manganese has a compositional range of up to about 5 wt %.