"etching" transparent conductor on transparent plastic film or glass?
You can buy glass with Indium-Tin-Oxide coating and etch it with 55% HCL at room temperature. The Adafruit item is out of stock, but it should be possible to find other suppliers. Thickness of the ITO is 1850Å. 

Etch rate is approximately 25Å (2.5nm) /second. Good results were reported using AZ 1350H photoresist. Total etch time would be less than 1.5 minutes. 

You would need something like film and a vacuum exposure setup to get good resolution and exposure.