Cleaning of substrates

The quality of the coatings is a critical point in the production of high power laser components. And that quality starts with the cleaning of the substrates before coating, to eliminate all possible contamination.

At LASEROPTIK all suitable substrates are automatically cleaned in one of three available mul­ti chamber ultrasonic cleaning lines.

A robot system moves the substrates automatically, fol­lowing identical process steps. The total process takes 30 to 50 minutes.

If substrates are not suited for automatic clea­ning (for example hygroscopic material), they are manually cleaned under laminar flow conditions. This process is similar to the one descri­bed below, "Cleaning of coated optics".

Both, substrate cleaning and coatings are performed in well maintained cleanrooms. In any case cleaned substrates are inspected for 100% under a stereomicroscope before mounting them into the substrate holders and fixing them in the coating machine immediately afterwards.

Cleaning with
(generators for
40/80 kHz).
Power and duration
are varied due to the
needs of the
material to clean and
its condition. Used
detergents are
 2. ------------------->
The cleaning goods
are rinsed with
reverse osmosis (RO)
Repeat step 1.
Repeat step 2.
Pure water rinse
with DI water (de-
ionized), produ­ced in
circulating systems.
Lift-out, slowly lifting
out of the DI water
to guarantee
re­sidue-free drying.
Final drying by IR-

Cleaning of coated optics


Cleaning a substrate manuallyWe recommend to clean coated optics with clean air only. If the surface is very dirty you can try the following steps:

1) Blow off the optic with clean air or nitrogen to remo­ve particles.

2) Fold cleaning tissue (like lens cleaning tissue Whatman 105) or microfiber cloth (Toraysee MK14.5H) into a suitable form according to the size of the surface to be clea­ned.

3) Moisten the tissue or cloth with recommended solvents like isopropanol or ethanol.

4) Clean the coated surface with uniform circular move­ments and low pressure. Coated optics produced by IAD, IP, MS and IBS can normally resist some more pressure.

5) The removal of the tissue or cloth from the coated surface should be straight and without any pressure.

6) Check the cleaning results with a bright light source and/or under a microscope.

7) Repeat the cleaning processes if the optic is still dirty.

Please note the following:

To avoid fingerprints use powder free clean gloves (latex, nitrile).
If you use tweezers to hold the substrate use twee­zers with protected tips (e.g. rubber or cork).
When cleaning small optics hold the folded tissue or cloth with clamp tweezers.
Change the tissue or cloth as often as possible.

This cleaning recommendation refers to optics which are coated with metal oxide layers and / or with a protective layer.

Please contact us for more information about cleaning of coated optics. We can assist you even on the phone.

Ultrasonic cleaning line for substrates in cleanroom environment
Ultrasonic cleaning line for substrates in cleanroom environment