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The influence of sputtering target purity and material uniformity on large-area coating production

high purity sputtering target

In the sputtering process of the coating of the target material, the quality of the target material is higher than that of the traditional material industry.

When the substrate with clean surface enters the high-vacuum coating chamber, if the purity of the sputtering target material is not enough, under the action of electric field and magnetic field, the impurity particles in the target material will adhere to the surface of the substrate during the sputtering process, causing the film in some places. The layer is not firm and peeling occurs. Therefore, the higher the purity of the target, the better the performance of the deposited film.

Taking the copper sputtering target as an example, it is inevitable that sulfur and lead will be introduced during the preparation of the copper target. The addition of a trace amount of sulfur can prevent the grain size from becoming larger and the generation of micro-cracks during the hot working process, which will cause the surface to be rough. However, when the sulfur content is higher than 18ppm, microcracks will appear again. With the increase of the two impurity elements of S and Pb, the number of target cracks and the number of arcing discharges will increase. Therefore, it is necessary to reduce the impurity content in the target as much as possible, reduce the pollution source of the sputtered film, and improve the uniformity of the film.

copper sputtering target

For sputtering targets with poor thermal conductivity, such as SiAl sputtering targets, heat transfer is often blocked due to impurities in the target, or the temperature of the cooling water used in production is different from the actual coating line water temperature, etc., causing the target to crack during use Under normal circumstances, slight cracks will not have a great impact on the production of coatings. However, when there are obvious cracks in the target material, the charge is very easy to concentrate on the edge of the crack part, which will cause abnormal discharge on the target surface. The discharge phenomenon will cause slag drop, abnormal film formation, and increased product scrap. Therefore, in the process of preparing the target, in addition to controlling the purity, the preparation process conditions should also be controlled.

For alloy sputtering targets, uneven material distribution often occurs, such as agglomeration of aluminum in the ZnAl sputtering target, segregation of aluminum in the zinc-aluminum target (the atomic mass of aluminum is 27 and the atomic mass of zinc is 65. During the cooling process, aluminum will float up, causing high side aluminum content and low side). Due to the low melting point, the agglomerated Al in the ZnAl target is prone to dross during the sputtering film formation process, and the amount of Al added during the spraying process is fixed. When part of the agglomeration occurs, it indicates that the aluminum content in other locations is less, which affects the ZnAl target. Therefore, the sputtering rate will not appear, the uniformity of the film will be deteriorated, the target will be cracked, the phenomenon of the target discharge will be aggravated, and the quality of the film will also be reduced. The segregation of target components will affect the sputtering rate (film uniformity) and film composition. Therefore, in addition to controlling the purity of the target material, the distribution of the material in the alloy target is also very important.

Xinkang Target is a manufacturer of sputtering targets. We focus on producing high-purity sputtering targets with the highest possible density and the smallest possible average grain size for semiconductor, chemical vapor deposition (CVD) and physical vapor deposition (PVD) display and optical applications. If you want to inquire about the price of any target material and have any questions about the target material, please contact us.

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