sensor design and mass test system development
DESCRIPTION
Sensor design and mass test system development. Y. Kwon (Yonsei Univ.). F irst real scale prototype chip from CERN. Our involvement. Participation in chip design Preparation of mass test system. Chip design. Chip design opportunities. Interesting approach based on CIS technology - PowerPoint PPT PresentationTRANSCRIPT
Sensor design and
mass test system development
Y. Kwon(Yonsei Univ.)
First real scale prototype chip from CERN
Our involvement
• Participation in chip design • Preparation of mass test system
CHIP DESIGN
Chip design opportunities
• Interesting approach based on CIS technology • Joint efforts with Prof. M. K. Song @ Dongguk Univ.• 2013-2014 : two master degree course students • 2014-2015 : two doctorate degree course students
– Student 1 : Daehyeok Kim• Continuation from 2013• Involvement in front end development
– Student 2 : Sungjoo Lee• New involvement• Past experiences in analog/digital circuits.
Front end under study
Interesting features
MASS TEST SYSTEM
Issue for the mass test system
• 50k delicate pixel sensors– Test configuration
• Probe card• Chuck• Test definition : Laser, readout
– Automation (machine vision + robot, commer-cial solution available)• To pick chips from tray, • load them on chuck, • test them according to the test configuration, • and return to the holder.
Minimum system to do custom chip test.
Probe-card
PAD layoutTotal 103 pads to make contact
Task 1, probe card
FPGA
CPU
ETH
ER
NET
Specification
1. 103 x 2 = 206 pins.
3. 8 LEDs to check probe card position by eye.
4. Contact status check at every 10 ms.
5. Contact status report by ethernet.
0. Dual pins for each pad Pin A for external connection (power/ground/IO), Pin B to check pin contact with the pad
2. 14 + 3 relays as switches when we decouple pin A and pin B
PAD sizeWe want dual pin contact for each pad.
Probe needle layout
Invisible
Chip
Programming option
• Computer + ethernet– Slow, but flexible
• On-board CPU– In-between
• FPGA– Fast, but limited
Pin A
Pin B
Input
Algorithm to check contact
1. Disconnect power/input using relay.2. Send 1.8(V) logic pulse to each digital input pad via
pin A and read pin B.
If no pair read back, raise chuck via .If any pair reads back, 3. Start careful adjustment ’. 4. Send 1.8(V) sequential logic pulse to other digital input
pad via pin A and read pin B.
5. Raise ’ up until all input pad pairs read back.6. Send 1.8(V) sequential logic pulse to digital input pads
via pin A and read pin B. (We will skip step 6 if we worry damage by electrical shock).
7. Raise ’ up until all input pad pairs read back.8. FPGA pull down for power pin B, FPGA pull up for ground pin B. 9. Disconnect FPGA output for pin A.10. Connect power.11. Check FPGA pin status12. Raise ’ up until all pin B status is OK.13. Disconnect pin B for analog input.
Use LED to display current status properly.
FPGA flexibility enables variation of algorithm.
Chuck
Transparent chuck?
Suction control
One hole
Would sensor be flat on the chuck?
Problem
ChuckVacuum holeChuck
Sensor
Solution
More small holes, air-tight chuck
Chucks in preparation
We are evaluating the optimal configuration.
Test definition : Laser, readout
Test definition?
• Basic elements are ready.• Open chuck in page 24– Laser (1000-1100 nm)?– X-Y stage with optical mask
• Requires further communication with CERN
Status
• Optimization in progress with the de-livery of proto type sensor.
• R&D in coordination with CERN --- We exchange experiences.