Molybdenum Sputtering Target via Electric Discharge Plasma Sintering
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Solution Overview
Problem
Conventional methods for manufacturing molybdenum sputtering targets for CIGS solar cells face challenges in achieving high density, uniform composition, and purity, particularly due to limitations in crystal particulate control and high processing costs associated with long molding processes and external heating methods.
Innovation Solution
The method employs an electric discharge plasma sintering process, where molybdenum powder is filled into a graphite mold, heated under controlled pressure and temperature conditions, with a temperature elevating pattern and vacuum environment to produce a high-density, uniform, and pure sputtering target in a simplified and shortened process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dissolution/casting method is used to manufacture molybdenum sputtering targets, then mass production is facilitated and manufacturing costs are reduced, but crystal particulate control is limited and high density achievement is difficult
Solution Approach 1:
The patent replaces the conventional dissolution/casting method with a powder metallurgy process using electric discharge plasma sintering. This substitution enables precise control over crystal particulates and achieves high density (95% theoretical density) while maintaining productivity through a streamlined single-step sintering process that eliminates multiple intermediate steps required by traditional methods.
Solution Approach 2:
The patent applies specific sintering parameters including temperature range of 1000-1500°C, pressure of 50-70 MPa, and sintering time of 5-30 minutes to achieve optimal density and microstructure. These controlled parameter changes enable precise manipulation of crystal growth and particle consolidation, resolving the contradiction between production efficiency and manufacturing precision.
2Manufacturing precision
If the conventional powder metallurgy method with HIP or HP is used, then high-density sintered bodies can be obtained, but the process time is long and processing costs are high
Solution Approach 1:
The patent implements continuous heating and sintering through electric discharge plasma, eliminating the need for separate heating and pressing stages. This continuous process achieves high density (95% theoretical density) in just 5-30 minutes, compared to the multi-hour processes required by conventional HIP or HP methods, thereby significantly reducing both time and cost while maintaining high manufacturing precision.
Solution Approach 2:
The patent rushes through the sintering process by applying high energy density electric discharge plasma, achieving complete densification and phase formation in minutes rather than hours. This rapid processing skips the lengthy intermediate stages of conventional methods while still achieving the desired high density and uniform microstructure.
3Manufacturing precision
If the conventional powder metallurgy method with HIP or HP is used, then high-density sintered bodies can be obtained, but crystal particulate control is limited due to long molding process time
Solution Approach 1:
The patent uses precisely controlled sintering parameters (temperature: 1000-1500°C, pressure: 50-70 MPa, time: 5-30 minutes) to achieve both high density and excellent crystal particulate control. The short processing time prevents excessive grain growth while ensuring complete densification, maintaining uniform composition and fine crystal structure that would otherwise deteriorate in longer conventional processes.
4Productivity
If electric discharge plasma sintering is used, then high density and uniform composition can be achieved in short time, but the process requires precise control of temperature and pressure parameters
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor temperature, pressure, and discharge parameters in real-time during sintering. This feedback system automatically adjusts process conditions to maintain optimal values, enabling precise control of the complex multi-parameter process while achieving high productivity and consistent quality across production batches.
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 molybdenum sputtering target with high density, uniform composition, and high purity, reducing processing costs and time, while minimizing particle growth and maintaining fine crystal structures, suitable for efficient solar cell performance.
Implementation Method 1
electric discharge plasma sintering process
Implementation Method 2
electric discharge plasma sintering process
Implementation Method 3
vacuum environment
Implementation Method 4
electric discharge plasma sintering process
Data Source
AI summary
A method for manufacturing a molybdenum sputtering target for a back electrode of a CIGS solar cell is provided to minimize thermal activating reaction by employing an electric discharge plasma sintering process. The method for manufacturing a molybdenum sputtering target for a back electrode of a CIGS solar cell comprises the steps of: charging molybdenum powder in a mold of graphite material, mounting the mold in a chamber of an electric discharge sintering apparatus, making a vacuum in the chamber, forming the molybdenum powder to the final target temperature while maintaining constant pressure on the molybdenum powder, heating the molybdenum powder in a predetermined heating pattern when reaching the final target temperature, maintaining the final target temperature for 1 to 10 minutes, and cooling the inside of the chamber while maintaining a constant pressure.