1. Target Area and Load Power Range
(1) The power density of a circular planar magnetron target is generally 1 ~ 25 W/cm2.
(2) The power density of a rectangular planar magnetron target is generally 1 ~ 36 W/cm2.
(3) The power density of a cylindrical magnetron target or a conical planar magnetron target (S gun) is generally 40 ~ 50 W/cm2.
2. The Actual Load Power of the Magnetron Target
The actual load power of the magnetron target is closely related to the cooling conditions and the heat dissipation conditions of the target, in addition to the factors such as the sputtering process, quality requirements of the film and so on. Magnetron targets can be divided into two types: “target direct water cooling” and “target indirect water cooling”, according to the cooling method.
Considering that the heat dissipation conditions of the sputtering target will deteriorate after a long-term use, the actual maximum power of the direct water cooling target should be slightly less than the upper limit of the power density range considering the difference in the heat dissipation coefficient of different target materials, as well as the ultimate load power of the magnetron target. The actual maximum load of the indirect water cooling target can be selected according to about one-half of the upper limit of the power density range.
When magnetron targets (mainly Cu, Ag, Brass, and Al bronze) “self-sputtering”, a magnetron sputtering target that is specifically designed to “direct water cooling the target” is generally used. The actual load power when used should be greater than the upper limit of the target power density range (ie, >100 W/cm2 or more).