Low-Carbon CuMn Sputtering Target via Late Alloy Addition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional copper-manganese (CuMn) sputtering target manufacturing processes 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 film adhesion in semiconductor integrated systems.
Innovation Solution
A vacuum induction melting (VIM) method is employed with a Programmable Logic Controller (PLC) to add manganese and active elements, such as oxygen, iron, sulfur, and chromium, as a late addition into the stirring wakes of the molten copper, forming a low carbon defect CuMn sputtering target with reduced defect levels by preventing contact with the crucible walls and utilizing carbon getters to form evaporable gaseous forms of COx.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional VIM processes are used to manufacture CuMn sputtering targets, then the manufacturing process is simple and straightforward, but carbon-based defects are generated due to reactions with graphite crucibles
Solution Approach 1:
The patent extracts manganese and active elements as a separate alloy addition that is added late to the molten copper, preventing contact with the graphite crucible walls that would otherwise cause carbide formation. This extraction of the alloying step from the initial charging process eliminates the source of carbon-based defects.
Solution Approach 2:
The patent performs preliminary action by adding manganese and active elements after the copper has already melted and is being stirred, rather than charging them together with the copper. This timing ensures that the alloying elements are incorporated into the bulk melt without contacting the crucible walls, preventing carbide formation before it can occur.
2Stability of the object's composition
If alloy elements are added early in the melting process, then the alloying is more thorough, but contact with crucible walls causes carbide formation and homogeneous nucleation
Solution Approach 1:
The patent uses the stirring wake of molten copper as an intermediary medium to transport and distribute the alloying elements throughout the melt. By adding manganese and active elements to the stirring copper, the copper itself acts as a carrier that distributes the alloys uniformly without allowing contact with the graphite crucible walls.
Solution Approach 2:
The patent converts the potential harm of graphite crucible contact into a benefit by using the graphite crucible only for heating copper, while adding alloying elements separately to the molten copper. The graphite crucible's heating function is preserved, but its harmful carbide-forming interaction with alloying elements is eliminated by sequential addition.
3Reliability
If manganese is added as a late addition to molten copper, then contact with crucible walls is prevented, but the alloying process becomes more complex
Solution Approach 1:
The patent maintains continuity of useful action by adding manganese and active elements to the continuously stirring molten copper. The stirring process continues uninterrupted during the alloy addition, ensuring continuous incorporation and distribution of the alloying elements throughout the melt, which simplifies the process despite the sequential addition steps.
Solution Approach 2:
The patent applies self-service by using the natural convection and stirring of the molten copper to automatically distribute the alloying elements throughout the melt. The molten copper's own motion and circulation patterns do the work of mixing and distributing the alloys, eliminating the need for additional mechanical mixing equipment or complex agitation systems.
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 method achieves a significant reduction in defect levels by over 50% compared to traditional VIM processes, as demonstrated by ultrasonic defect inspection, resulting in improved film quality and adhesion.
Implementation Method 1
vacuum induction melting (VIM) method
Implementation Method 2
add manganese and active elements, such as oxygen, iron, sulfur, and chromium, as a late addition into the stirring wakes of the molten copper
Implementation Method 3
utilizing carbon getters to form evaporable gaseous forms of COx
Implementation Method 4
form evaporable gaseous forms of COx
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 %.