In the production process of sputtering target materials, the hot and cold systems play a key role and have an important impact on material properties, production efficiency and equipment life. The following are the main requirements of the hot and cold systems in the production process of sputtering target materials:
I. Melting and sintering links
1. High temperature control
- In the melting process, equipment such as vacuum arc melting furnaces need to operate under conditions exceeding the melting point of the material (for example, the melting point of titanium is 1668℃) and be in a high vacuum or inert gas protection environment to prevent material oxidation.
- The sintering process requires a temperature of 1300-1500℃. By precisely controlling the heating rate and the holding time, the material particles can be metallurgically bonded to increase the density of the target material.
2. Cooling rate management
- When the liquid material solidifies, the cooling rate will affect the grain structure. In order to avoid cracks or segregation, mold temperature control or slow cooling is required.
II. Heat treatment link
Precise temperature control
- The temperature of annealing or solution treatment is generally set at 800-1000℃, and the temperature fluctuation needs to be controlled within ±5℃ to improve the toughness and microstructure of the material.
- When cooling, air cooling or water cooling can be used, but the cooling must be uniform to prevent the target material from deforming due to thermal stress.
III. Sputtering process link
1. Efficient cooling requirements
- Target cooling: During the medium-frequency magnetron sputtering process, the surface of the target material will generate high temperature (the temperature may exceed 200℃) due to electron bombardment, so a water cooling system is required, such as using a water jacket or a circulating water chiller to control the target temperature below 60℃ to avoid deformation or performance degradation of the target material.
- Equipment heat dissipation: The medium-frequency power supply, magnetron head and other components in the sputtering equipment will heat up due to the current skin effect, and need to be cooled in time by water cooling or air cooling to ensure that the equipment can operate stably.
2. Temperature control accuracy
- The temperature of the cooling water needs to be stable at ±0.1℃, and the flow rate needs to be controlled at more than 0.5L/min, so as to ensure that the temperature distribution of the target material is uniform, thereby improving the quality of the film.
IV. Post-processing link
1. Step-by-step cooling design
- A three-stage cooling system is used, which is followed by normal temperature water cleaning, ice water rapid cooling and cold air drying. This can avoid the internal stress of the target material due to sudden cooling, and can also remove impurities on the surface.
- For example, the first cooling chamber uses normal temperature circulating water for cleaning and preliminary cooling, the second cooling chamber uses ice water for rapid cooling, and the third cooling chamber uses a cold air blower for drying.
2. Impurity filtration circulation
- The cooling water circulation system needs to be equipped with a filtering device, such as a filter screen or a filter plate, to remove impurities such as metal debris generated during the target material processing to prevent the nozzle from clogging or contaminating the target material.