Jerome Charmet,

I have been using thin dry film photoresist having thickness of 25 microns. And
I have heard that most of the supplier's thinnest film product is around 10
microns.
But Asahi Kasei can make 7 microns film for experimental purpose not mass
production. This is due to the micro pinholes and damages that attributes to
the low yield of thin (less than 15microns) film.

http://www.asahi-kasei.co.jp/asahi/en/index.html

Hope this could be of help.

   >I am looking for a thin dry film photoresist (thickness around 5 microns).
   >Does this kind of article exist and where can I find it (supplier)?

Best regards,
Regan Nayve