I am looking at increasing the aspect ratio of photo-chemically etched micro holes. The aspect ratio of photo-chemical etching is usually 1:1 where as I am looking at 1:5 to 1:10 aspect ratio. So I am thinking of joining such 5-10 sheets together after micro-aligning the sheets.

For this is it possible to use cold welding method or diffusion welding  or induction welding? Which method is preferable so that Fusing of aluminium sheets should happen without damaging the micro holes?

If yes, Can some one please guide me on how to achieve this? What grade of aluminium to use? How to clean the aluminium? What pressure/temperature to apply etc..

I have 1 square feet sheets of aluminium  with 100 micron holes in it. The sheet thickness is 100 microns. 

Thanks