Are you talking about wet or dry etching? Thanks, Andrew

Its wet etching...

You can use Chromiun Mask Etchant N1 from Technic France. The company address is: 15 rue de la Monjoie BP79 F-93212 Saint Denis La Plaine CEDEX tel: 0149465100

Chromium can be etched with 6 wt % nitric acid and 16 wt % ceric ammonium nitrate in water.

Thank you Catherine. Any idea of the etch rate?

I do not have personal knowledge but here is a reference: http://engineering.tufts.edu/microfab/index_files/SOP/ChromiumEtch_SOP.pdf

Dear All,

In producing chromium mask for optical lithography, I use this wet etching, which is veryu good with optical resist:

35 ml CH3COOH

600 ml H20

200 g (NH4)2Ce(NO3)6

You don't need to heat, the etching rate is 60-100 nm/min (depending on the stirring rate)

Hope this will help you

You can purchase a chrome etchant from Microchemicals, Sigmaaldrich, Union Etchants, or from other vendors. Make sure to read the product specification sheets very carefully and follow the manufacturer's recommendations on how to use the product. They will also have a recommendation on etch rate and the suitable photoresists (positive and/or negative). They usually test the products multiple times before they release it to the market. Once you are familiar with your projects' needs, you can prepare your own chrome etchant to save on your financial resources. But, take note that chrome etchants are not expensive to begin with so it may be best to purchase the commercially available ones.

Thank you very much Zordia Aguilar for the suggestion. I have achieved my goal. Thanks a lot.

What about the dry etching of the Chromium?

Here is a dry etch recipe:

http://www.mmf.montana.edu/processes/chromium-dry-etch-recipe

thanks Catherine.