Calorimetric Measurements of the Temperature of Metal Targets during Magnetron Sputtering

Direct measurements of the temperature of $\mathrm{C u}$, $\mathrm{Ti}, \mathrm{Cr}$ targets (3 mm thick, $\varnothing \mathrm{5 5 m}$) using thermocouples attached to the front (erosion zone) and back (cooling) sides of the targets during magnetron sputtering (DC MS) were carried. The variables: target mode (cooled or uncooled target); working gas ($\mathrm{Ar}, \mathrm{N}_{2}$); discharge power per unit area. It was shown that the target temperature reaches $\sim 730 \mathrm{~K}$ on the front and $\sim 530 \mathrm{~K}$ on the back sides of the cooled target, while for the uncooled target it is $\sim 1050 \mathrm{~K}$ and 950 K, respectively (Cu target). For both modes and all targets, the target temperature is slightly higher when sputtered in N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. Based on temperature measurements on opposite sides of the $\mathrm{C u}$ target, its dynamic thermal conductivity (thermal conductivity that exists during target operation) is calculated. It turned out that it is $\mathrm{\sim 1 0 0}$ times lower than the thermal conductivity of normal Cu. The above results are discussed based on a physical model that assumes the appearance and existence during sputtering on the target surface a layer which properties strongly differ from those of ordinary metals.