The purity of the sputtering target material has a greater impact on the performance of the film to be coated.
When the clean glass enters the high-vacuum coating chamber, if the purity of the sputtering target is insufficient, the impurity particles in the sputtering target will adhere to the surface of the glass during the sputtering process, causing some positions under the action of the electric field and magnetic field. The film layer is not strong and there is a phenomenon of peeling. Therefore, the higher the purity of the sputtering target, the better the performance of the deposited film.
It is inevitable that sulfur and lead elements will be introduced during the preparation of Cu sputtering targets. The addition of trace S can prevent the grain size from becoming larger and the generation of micro-cracks during thermal processing, which may cause the surface to be rough. However, when the S 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.
For sputtering targets with poor thermal conductivity, such as SiA1 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. Bottom, slight cracks will not have a great impact on the coating production. 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 surface of the target. 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 aluminum agglomeration in the SiAl target and aluminum segregation in the zinc-aluminum target (the atomic mass of aluminum is 27 less than the atomic mass of zinc 65. After casting, the cooling process China Aluminum will float up, causing high side aluminum content and low side aluminum content). Due to the low melting point, the agglomerated Al in the SiA1 target is prone to dross during the sputtering film formation process, and the amount of A1 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 SiA1 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.
The above is the impact of sputtering target purity
and material uniformity
on large-area coating production. If you have any questions, you can contact us