Slide 1

Atsuhiko Ochi Kobe University 28 August 2012 ATLAS muon chambers R&D on micromegas meeting

Slide 2

Screen printing is suitable technique for large size board. Very simple step to make it. Current production way of the MM strips. Making pattern (negative) of strips. Painting the resistive ink. Scraping surface. Etching the negative pattern Our proposal of new production Printing the resistive strips. Thats all!! Edge of strips will be rounded. More stable operation will be expected. Etching methodPrinting method 2012/8/28 A. Ochi, Kobe Univ.2

Slide 3

Printing technique that uses a woven mesh to support an ink-blocking stencil It is common technology for large size printing. Many type of inks can be used. Thick printing is available (a few 100 microns). 3 2012/8/28 A. Ochi, Kobe Univ. squeegee frame Screen ink stencil

Slide 4

2012/8/28 A. Ochi, Kobe Univ.4 Screen printing machine Screen Printed strips on a polyimide film Putting the ink (resistive polyimide) on the screen Now printing

Slide 5

Resistive material Resistive Polyimide, made by Toray. We are contacting with Toray people to improving the material. This material is not provided commercially. Curing step (90 350 degree) is needed. Art work and printing Made by Raytech Inc. Metal screen with polyimide stencil was used. Size of prototype 10cm X 10cm with 400 micro meter pitch. 2012/8/28 A. Ochi, Kobe Univ.5

Slide 6

Using typical screen printing method Screen: Polyester Stencil: Sensitive emulsion Results First print was good. From second print Very bad quality. We are using NMP (n-methyl- pyrrolidine) to clean up the screen, however, it dissolves also emulsion pattern. We need other screen type!! Printing pattern (first one) Dissolved emulsion pattern 2012/8/28 A. Ochi, Kobe Univ.6

Slide 7

A special screen was made Made from polyimide film with copper foil (with 40 micron of nickel plating.) Screen: Copper and nickel Stencil: Polyimide (50 micro meter thickness) Results Bad quality Too many ink are printed, and strips are bleeded. Need thinner stencil Polyimide Printing inks are stored in this space. 2012/8/28 A. Ochi, Kobe Univ.7

Slide 8

Making thinner stencil: Stencil: polyimide (25 micron) Results Some of samples have better quality. Resistivity: 10M /cm But, the inks are still too much. More more thinner stencil is need Microscopic Picture of printed strips (good quality sample) 2012/8/28 A. Ochi, Kobe Univ.8

Slide 9

Making moreover thin stencil: Stencil: polyimide (13 micron) Results The amount of ink is good There are some good samples However some bleedings are found Sometimes, screen of all printing area was attached while printing. It should be attached only squeegee is on it. The screen parameters are almost OK. Remained problems are parameter settings of screen tension and squeegee pressure. 2012/8/28 A. Ochi, Kobe Univ.9 10cm 2mm

Slide 10

2012/8/28 A. Ochi, Kobe Univ.10

Slide 11

We have started to make a resistive strips using screen printing method. We have tried to several times to print, and we are achieving to good condition for production. We will make a MicroMEGAS test board just after screen printing technique will be established. Using bulk MM technique. We will make prototype in this September or October. (Manufactured by Laytech Inc.) Large size printing machine (or hand printing equipment) should be newly-prepared. 2012/8/28 A. Ochi, Kobe Univ.11