Transcript Last_news_largeMPGD - Indico

Recent achievements and
projects in Large MPGDs
Rui de Oliveira
21/01/2009
RD51 WG1 workshop
Content
• Large GEMs
– CERN production situation
– Companies contacts
• Large Bulks
– CERN production situation
– Resistive protection
– Companies contacts
Large size process
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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 500mm
100 meter 500mm
2 meter x 500mm
Drying
2 meter x 500mm
Diff etch
2 meter x 500mm
GEM
2 meter x 450mm
Active area
In theory with
CERN
equipments
Polyimide etch
2 meter x 500mm
Resist development
100 meter x500mm
Copper etch
100 meter x500mm
Goal
•
2 meter x 450mm GEM
• Single mask process
• 2um Copper on both sides
70um
70um
55um
50 to 60um
STD
Single mask
Single Mask GEMs produced in 2008 (650mm x 400mm)
Problems:
-large rims on the top
-up to 90um copper diameter on top
-uniformity on large pieces
-lower gains
Bottom
Top
Single Mask GEMs produced in 2009 (30mm x 30mm)!!
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 700mm x 450mm
– DHCAL 1000mm x 330mm
• 2 slides following given by Mr Jae Yu
UTA’s 100cmx100cm Digital Hadron Calorimeter Plane
Readout Board
330x500 mm2
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 m2/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 2meter GEMs for chemical
treatment (done)
• Subcontract artwork ( 0.5m x 2m) (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
1300mm x 350mm
Active area
1500mm x 500mm
Outer size
Mesh
Drift frame
Gas box
6 different patterns
500um
Full plane
High voltage supply
6 sectors + drift
250um
500 um pitch
400um line and space
Signal outputs
250 um pitch
150um line and 100um space
250 um pitch
With resistive protection
Resistive protection
Spark or charges
50 to100um
Signal out
PCB
Copper
Photo-imageable coverlay
Resistive dot, pad or line
Spark or charges
dot
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
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
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
100Ohms to MOhms
Introduce a metallic hat C
Increase the distance C
Dot architecture
-Min : 0.15mm diameter
-Pitch: 0.25mm
-Possibility to avoid alignment
between track and dots
Pad architecture
-needs alignment
Detail on the sector partitioning
Coverlay
0.8mm 0.6mm 0.8mm
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