CCDs for DECam

1
CCDs for DECam
Baseline SNAP CCDs from LBNL (E2V or others are
not excluded) higher QE at near-IR nearly ready
(submit pre-production) potentially lower cost
(processing LBNL finishes backside processing
FNAL does packaging End product is a module
CCD sensor Al N board(s) for support/CRIC
On-plane electronics and cable Other
support/thermal to focal plane
2
Near IR Response
3
Recent progress

• LBNL has received v.1 SNAP wafers
• Business model continues to look promising
• In December, concern was the last top metal step.
  Normally Al could not withstand a high
  temperature backside process. DALSA top metal
  processing with Ti N looks promising
• LBNL did acquire a plasma etcher for top side
  processing with Al
• CRIC prototype has read out a LBNL CCD
• LBNL desires an on-site furnace (400K)

4
SNAP 150mm layout
SNAP 18 mm pixel spectrograph CCD
800 x 1980 NOAO MARS (2x, 1 12 mm pixel with
design for high voltage)
470 x 1264 24mm Lick Guider (2x) (1 with 2-stage
amp)
SNAP 35122
Template for 100 mm cut down if necessary
1k x 512 (4x)
2210 x 802 9mm 2-stage amps (4) 20 fps (4x)
SNAP 9 mm Pixel spectrograph CCD 2226 x 868
5
SNAP 18 mm pixel spectrograph CCD
800 x 1980 NOAO MARS (2x, 1 12 mm pixel with
design for high voltage)
470 x 1264 24mm Lick Guider (2x) (1 with 2-stage
amp)
SNAP 35122
1k x 512 (4x)
2210 x 802 9mm 2-stage amps (4) 20 fps (4x)
SNAP 9 mm Pixel spectrograph CCD 2226 x 868
6
Meeting at LBNL

• Random thoughts of M. Levi, C. Bebek, S. Holland,
  H. von der Lippe, W. Wester, and J. Fast
• Modification of mask design 1 week effort with
  3 months of verification
• No specific 2K x 4K submissions
• Readout 100kps could be increased x2
• Packaging is a major issue 50K for packaged
  devices seems like a bargain.
• Schedule is a driver
• Packaging going on at Lick, Yale Arizona

7
Other new knowledge

• Slew times closer to 30 sec not 10 sec
• 100 kps readout of 24582 (4 amplifiers) is 15 sec
  and 200 kps becomes
• Gaps in focal plane layout are important
• Need 5 years to ensure 3 exposures
• Fill factor less important than tiling step
• Its the economy stupid (and the schedule)
• We need to be doing things now with no money
• Baseline SNAP CCDs with 24582 15 mm2
• Use existing SNAP devices as our prototype
• Piggyback (and contribute) to packaging RD
• (2K x 4K not completely excluded)

8
Focal plane layout

• Still some options that depend mostly on the
  corrector. 70 devices, 74, or 79

420mm FOV
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Cost and schedules

• Work towards reading out CCDs at FNAL
• 50-100K and 1 year is required
• Buy some SNAP CCDs
• Pay for some packaging
• Set-up dewar
• Set-up test stand
• Production order 1-1.5M
• 48 wafers x 4 devices x 50 yield 96 gradeA
• Includes packaging MS and CRIC chip
• Testing effort 250K (dewars DAQ)