Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

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New resistive Micromegas electrodes made with sputter deposition Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6

Transcript of Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Page 1: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

New resistive Micromegas electrodes

made with sputter deposition

Atsuhiko OchiKobe University / MAMMA collaboration

24/04/2013 RD51 mini week, WG6

Page 2: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

High position resolution for one dimension◦ <100 μm for eta direction.

(Resolution of a few cm is allowed for second coordinate.)

Tolerant for high rate HIP particles◦ ~ 5kHz/cm2

Resistive layer should be formed as strips

There should be a technology for large size production (~1m)

Mass production should be available◦ A few thousand board should be

produced in 1~2 years. Low cost is preferable

24/04/2013A. Ochi, RD51 mini workshop 2

Requirements for ATLAS NSW MM

+HV

Mesh(GND)

Page 3: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Screen printing is used for current prototypes (@ CERN and Japan)◦ 400 μm pitch was available, but less

pitch is very difficult (in our experience)

We have proposed new technique :Sputtering with lift off process◦ Less than half pitch of readout strips

can be formed We will not need to take care the

alignment between resistive strips and readouts.(We have to confirm it)

24/04/2013A. Ochi, RD51 mini workshop 3

Resistive strips depositionReadout strips

Resistive strips

Page 4: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Very fine structure (a few tens micro meter) can be formed using photo resist. (same as PCB)

Surface resistivity can be controlled by sputtering material and their thickness

24/04/2013A. Ochi, RD51 mini workshop 4

Liftoff process using sputtering

Substrate (polyimide)

Photo resist(reverse pattern of surface strips)

Substrate (polyimide)

Metal/Carbon

sputtering

Substrate (polyimide)

Developing the resists

@PCB company(Laytech inc.)

@Sputtering company(Be-Sputter inc.)

@PCB company(Laytech inc.)

Page 5: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

We can divide the production process of resistive strip from that of readout board.◦ Resistive strip is formed on thin foil◦ Because of fine pitch, < 200 micron, we don’t need fine

alignment between resistive strips and readout strips. Dividing those processes will make the yield of

production growing up.

24/04/2013A. Ochi, RD51 mini workshop 5

MM PCB production with parallel process

Readout board

ResistiveStrip foil

Page 6: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

PCB company◦ They are expert for FPC (Flexible Printed Circuit)

production.◦ Liftoff is basic process for FPC production

For patterning process: Laytech inc.

Exposure machines in clean room

Electro forming machines Etching machines

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Page 7: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Laytech inc has many experiences for producing MPGDs.◦ μ-PIC with resistive cathode◦ GEM with resistive foil◦ MicroMEGAS with screen

printing technique

Fine patterning for MPGDs

1 mm

1 mm

μ-PIC with resistive cathode

Bulk MicroMEGAS with screen printingresistive strips

24/04/2013 7A. Ochi, RD51 mini workshop

Page 8: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Sputtering company They have large

sputtering chamber◦ Φ1800 X H2000◦ 1m X 4.5m (flexible board)

can be sputtered They have special

technology for uniform sputtering for large area

Sputtering process

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Page 9: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Large size sputtering is available.◦ 4.5m X 1m

Two layer stack sputtering is available◦ Using two separated

target Very good uniformity

◦ Less than nm size difference, using their special technology

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Sputtering facilities

Vacuum chamber (with Ar gas)

Rotating drum4.5 m round

Sample

Sputteringtarget

Page 10: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Tungsten and Carbon are sputtered on polyimide (25μm thickness) foil◦ Surface resistivity of first

sample (W 10Å, C 300Å) was 8MΩ/sq.

◦ Adhesion of coating is very strong. No resistivity change with rubbing surface by cleaning paper.

◦ No resistivity change found after long exposure (1 week) to air

24/04/2013A. Ochi, RD51 mini workshop 10

Prototype of resistive foil

Substrate (polyimide)

Carbon (300-600Å)Tungsten (10-50Å)

Page 11: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Fine strip pitch of 200 μm is formed. It will be possible to make more fine structure.

It keeps strong adhesion and stability

24/04/2013A. Ochi, RD51 mini workshop 11

Fine patterning with lift off process

Page 12: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Assumption:◦ Size of foils: 1000mm x

500mm◦ Quantity: 3000◦ Sputtering: W:10Å, C:600Å

500 foils / month can be produced◦ 8 foils can be sputtered

simultaneously in one batch.◦ Sputtering time is estimated 2

hours.(Including overhead, 3 hours / one batch)

◦ 24h/3h x 8 foils x 20days = 1280 foils / month(Applying safety factor >2 500 foils/month )

◦ It will take half year, for full production.

Cost estimation (Very rough, but probably upper limit)◦ Sputtering cost:

1k CHF / one batch (for spattering 8 foils)130 CHF / foil )

◦ It is not sure for the cost of liftoff process, but it is estimated around 200 CHF/foil

◦ Total 330 CHF/foil, 1M CHF for full production

Mass production feasibility

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Screen printing case (@CERN, by Rui)

Page 13: Atsuhiko Ochi Kobe University / MAMMA collaboration 24/04/2013 RD51 mini week, WG6.

Resistive electrodes, using sputter technology, are proposed and produced for MPGD production

In our first prototype, surface resistivity is around a 8MΩ/sq., with 10Å tungsten + 300Å carbon.

Very fine (<100 μm) and robust patterns are formed on polyimide foil

Prototype production is taken place at industrial companies Technology transfer is ongoing simultaneously

Both large size production and mass production are available using current facilities

This technique is proposed and tested for MAMMA now, and it will be used for almost all type MPGDs !

24/04/2013A. Ochi, RD51 mini workshop 13

Summary