Mn-Ta-W-Cu-O Sputtering Target Composition for Arc-Free DC Deposition
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Solution Overview
Problem
The use of composite sputtering targets for DC sputtering in optical information recording media is prone to abnormal discharge due to insulating grains, leading to damage and reduced yield in the recording film.
Innovation Solution
A Mn—Ta—W—Cu—O-based sputtering target with a relative density of at least 90% and containing a crystalline phase of Mn4Ta2O9 is developed, which suppresses abnormal discharge during DC sputtering and enables stable deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a composite sputtering target containing manganese oxide and inorganic elements such as W is used for DC sputtering, then productivity is improved by using direct current sputtering instead of high frequency sputtering, but insulating grains of WMnO4 or the like are included in the target which cause abnormal discharge (arcing) to occur due to insufficient conductivity
Solution Approach 1:
The patent changes the chemical composition parameters of the sputtering target by introducing specific elements (Ta, Cu, Zn) and controlling their ratios. Ta forms conductive Mn4Ta2O9 phase, Cu provides electrical conductivity, and Zn suppresses insulating grain formation. These parameter changes transform the target from insulating to conductive, enabling DC sputtering without abnormal discharge while maintaining high productivity.
Solution Approach 2:
The patent creates a composite material system combining multiple oxides (MnO, Ta2O5, WO3, CuO, ZnO) in specific proportions. This composite structure leverages the conductive properties of Mn4Ta2O9 phase formed by MnO-Ta2O5 interaction, while CuO and ZnO components further enhance conductivity and suppress insulating WMnO4 grain formation. The composite material achieves both high productivity and reliability.
2Device complexity
If a composite sputtering target is used to form a recording layer, then the device size is reduced compared to multitarget sputtering, but compositional deviation tends to arise and insulating grains are included which cause abnormal discharge
Solution Approach 1:
The patent precisely controls composition parameters within specific ranges: MnO 30-70 wt%, Ta2O5 10-40 wt%, WO3 5-20 wt%, CuO 5-20 wt%, ZnO 0-10 wt%. These parameter specifications ensure homogeneous mixing and prevent compositional deviation. The controlled composition guarantees formation of conductive Mn4Ta2O9 phase while suppressing insulating grain formation, achieving both compact device design and manufacturing precision.
Solution Approach 2:
The patent performs preliminary mixing of all target materials in precise proportions before sputtering. This preliminary action ensures homogeneous distribution of elements, preventing compositional deviation during the sputtering process. The pre-mixed target material maintains consistent composition throughout deposition, enabling accurate recording layer formation with a single compact target.
3Device complexity
If insulating grains are present in the composite sputtering target, then the target structure is simplified, but conductivity is insufficient which causes abnormal discharge (arcing) and damage to the recording film
Solution Approach 1:
The patent converts the potentially harmful insulating WMnO4 grains into beneficial conductive structures by controlling the MnO-Ta2O5 ratio to form Mn4Ta2O9 phase. This phase transformation converts insulating material into conductive material, turning the harmful effect into a beneficial one. The resulting target structure is both simple and highly conductive, eliminating abnormal discharge while maintaining structural simplicity.
Solution Approach 2:
The patent changes the chemical parameters by introducing Ta2O5 (10-40 wt%) and CuO (5-20 wt%) which fundamentally alter the electrical properties of the target. Ta forms conductive Mn4Ta2O9 phase, and Cu provides additional conductivity pathways. These parameter changes transform the target from insulating to conductive, eliminating abnormal discharge while keeping the target structure relatively simple and easy to manufacture.
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 Mn—Ta—W—Cu—O-based sputtering target effectively suppresses abnormal discharge during DC sputtering, ensuring stable deposition and improving the yield rate of the recording film.
Implementation Method 1
there is a multitarget sputtering method using a plurality of sputtering targets consisting of each element, and a method using one composite sputtering target containing a plurality of elements
Implementation Method 2
wet mixing a mixed powder containing manganese-containing powder, a metal tantalum powder, a tungsten-containing powder and a copper-containing powder for at least 10 hours
Implementation Method 3
sintering the mixed powder at a temperature of 750° C. to 950° C. applying a pressure of at least 550 kgf/cm2, after the step of wet mixing
Data Source
AI summary
Provided is a Mn—Ta—W—Cu—O-based sputtering target including, in the component composition, Mn, Ta, W, Cu, and O. The sputtering target has a relative density of at least 90%, and includes a crystal phase of Mn4Ta2O9. Also provided is a production method for the sputtering target.