Recent achievements and projects in Large MPGDs Rui

Recent achievements and projects in Large MPGDs Rui de Oliveira 21/01/2009 RD 51 WG 1 workshop

Content • Large GEMs – CERN production situation – Companies contacts • Large Bulks – CERN production situation – Resistive protection – Companies contacts

Large size process • • • Conventional process : ok but difficult LDI : Problem of alignment Large glass mask : mask planarity problem Single mask + electro-etch: not accurate Single mask + chemical selective etching: ok

Single mask technique quick reminder Raw material Single side copper patterning Chemical Polyimide etching differential etching or second metal etch

Raw material Resist lamination UV exposure 100 meter 500 mm 2 meter x 500 mm Drying 2 meter x 500 mm Diff etch 2 meter x 500 mm GEM 2 meter x 450 mm Active area In theory with CERN equipments Polyimide etch 2 meter x 500 mm Resist development 100 meter x 500 mm Copper etch 100 meter x 500 mm

Goal • 2 meter x 450 mm GEM • Single mask process • 2 um Copper on both sides 70 um 55 um 50 to 60 um STD Single mask

Single Mask GEMs produced in 2008 (650 mm x 400 mm) Problems: -large rims on the top -up to 90 um copper diameter on top -uniformity on large pieces -lower gains Bottom Top

Single Mask GEMs produced in 2009 (30 mm x 30 mm)!! Problems: -Still some delamination on top layer -Hole shape to deep for classical differential etching -Needs a protecting metal before second spray etch -uniformity seems good but need to be verified Bottom Top -Up to 30 different chemistry tested (for polyimide) -Effect of ultrasonic bath tested (for polyimide and metal) -NI/Au protection layer tested -removable Tin for production still to test

Detail on second metal spray etch Chemical Polyimide etching NI/Au or Tin plating on top Resist protection on bot Conventional spray etching stripping : Tin on top Resist on bot

• Next large GEMs productions – Kloe 700 mm x 450 mm – DHCAL 1000 mm x 330 mm • 2 slides following given by Mr Jae Yu

UTA’s 100 cmx 100 cm Digital Hadron Calorimet

10 00 mm Readout Board 330 x 500 mm 2 990 mm Base steel plate, t=2 mm

Future large volume production Visit November 2008, organized by Changwon university Company: NEW flex technology Started in 1992 Activities: circuits for Telecom, displays and Automotive 400 Employee Situation: South Corea near Seoul

Double sided flexes capacity 10 000 m 2/month !

Smaller than needed for GEMs

Roll to roll exposure, etching and stripping

Strategy for low to medium volume • Use the CERN equipment • Create tool to handle 2 meter GEMs for chemical treatment (done) • Subcontract artwork ( 0. 5 m x 2 m) (Ok) • Upgrade UV exposure and Polyimide etching equipment ( but still dead baths) – Existing ones sufficient to start

Strategy for large volume • Subcontract roll to roll copper patterning • Buy or create equipment for roll to roll polyimide etching (spray or static etching) • Buy equipment for roll to roll Tin plating • Buy equipment for roll to roll Tin stripping • Subcontract roll to roll electrode definition • Buy equipment for roll to roll cleaning

Micromegas Bulk • About to start 1 large Bulk for SLHC – Should be built within 1 month • Points to be verified (production) – size capability – Resistive protection against discharges – Mesh sectors creation

1300 mm x 350 mm Active area 1500 mm x 500 mm Outer size Mesh Drift frame Gas box 6 different patterns

500 um Full plane High voltage supply 6 sectors + drift 250 um 500 um pitch 400 um line and space Signal outputs 250 um pitch 150 um line and 100 um space 250 um pitch With resistive protection

Resistive protection Spark or charges 50 to 100 um Signal out PCB Copper Photo-imageable coverlay Resistive dot, pad or line

Spark or charges dot Signal out R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges

Spark or charges dot Signal out R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges Change the paste 100 Ohms to 1 MOhms

Spark or charges dot Signal out R Serial resistor limiting max current High enough to limit energy of spark C Serial parasitic capacitor High pass filter High enough to transfert signal charges Change the paste 100 Ohms to MOhms Introduce a metallic hat C Increase the distance C

Dot architecture -Min : 0. 15 mm diameter -Pitch: 0. 25 mm -Possibility to avoid alignment between track and dots Pad architecture -needs alignment

Detail on the sector partitioning Coverlay 0. 8 mm 0. 6 mm 0. 8 mm Read-out board Mesh Milling or scalpel cut Scalpel cut prefered No dust! Spacer pillar

First contact for large size large volume productions CIRE Group 8 companies in France Possibility to make large patterns in some of them They have already produced some small BULKS Other details are being discussed We are ready to discuss also with any other company

Thank you