**6. Deposition of very large‐size films**

We have developed special techniques for depositing thin films on rotating disks and trans‐ lationally moving ribbons. In this paragraph, we propose new solutions, which imply more than one target for deposition, allowing in case of a rotating substrate to shorten the deposition duration and in case of a ribbon to increase the ribbon width or the speed of depositing a film of the same thickness [12].

To reduce the deposition time for films on substrates of very large size, one can modify the above‐described way (see paragraph 2.3.) as follows: use several targets instead of one and scan a laser beam over them, applying target after target for deposition. If the laser pulse repetition rate increases in correspondence with the number of targets, the deposition from each target will be performed at the same frequency as in the case of one target. Each target must have its own diaphragm, moving simultaneously with the target at a velocity *V*=const/*r*.

Suppose we are going to use *N* targets to deposit a film on a substrate with a radius *R*. Obviously, the targets must be located with respect to each other and with respect to the substrate in such a way as, having started deposition from all targets simultaneously and moving each target at a velocity *V* = const/*r*, to deposit a film on the entire substrate surface and finish deposition from all targets simultaneously. It can be shown that, to deposit a film of uniform thickness on a substrate of radius *R*, the *N* targets must be initially located so as to provide a distance *Xl* (*t0*) = *R*(*l*‐1)1/2(*N*) ‐1/2 from the substrate center (**Figure 22**) to the point of intersection of the perpendicular dropped from the first target with the substrate plane.

**Figure 22.** Moving *N* targets.

**Figure 23.** Moving ribbon, *N* targets: 1, ribbon; 2, plasma torch; 3, target. (a) N times acceleration of sputtering process, (b) deposition on N time wider tape.

We can use more than one target also in the mask method (paragraph 3.2.3). Certainly, we can use more than one target as described in paragraph 5 designs for deposition on a moving ribbon. Using *N* targets, we can accelerate sputtering process *N* times (**Figure 23a**), or obtain a film on the tape which is *N* times wider (**Figure 23b**).
