Integrated Radiation-tolerant Imaging System Werner Ogiers - - PowerPoint PPT Presentation

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 1

GSTP – ASCMSA Analog Silicon Compiler for Mixed Signal ASICs Group 4 – Development of Microcamera

Integrated Radiation-tolerant Imaging System

Werner Ogiers FillFactory NV Schalienhoevedreef 20B B-2800 Mechelen www.FillFactory.com

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 2

Contractors

• 1997 – 2000
• Originally IMEC Image Sensor Group
• Since 12/1999 partly by FillFactory

– IMEC spin-off for CMOS imagers – transfer of all people/patents to new company – based in Mechelen, Belgium – activities

• custom and off-the-shelf CMOS camera chips
• studio digital photography
• high-speed imaging
• industrial vision
• aerospace

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 3

Overview

• Objective: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 4

Objective, SOW

… to design, develop, fabricate and test a novel microcamera chip, to be used as a monitoring camera for space applications with as few components as possible. … based on CMOS technology … allows for easy co- integration of … control logic … ADC … interfaces, and on the long term image compression circuitry IRIS Integrated Radiation tolerant Imaging System

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• Target: low-end

– Visual SC monitoring – Landers and rovers this contract – Robotics

• Feasible:

– Optical navigation TRP:ASCoSS(12227/96/NL/SB) Space Applications for CMOS APS

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Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 7

IRIS Challenges

• Integrated: CMOS APS + logic

– CMOS imagers immature – no mixed-signal experience

• Radiation tolerant: CMOS reputation

– zero knowledge – trust technology

• Imaging System

– choice of two CMOS APS styles

• direct readout
• integrating

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Technology? Direct readout

• Direct readout CMOS Active Pixel Sensor
• IMEC’s FUGA15 used on Teamsat
• Photo-current though resistor => V(t)
• Non-linear R => wide dynamic range
• No blooming
• Static offsets => correct with LUT
• No single-chip solution

raw image LUT processed image V=R.I(t) I(t) R

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Technology? Integrating

• Integrating CMOS APS
• ~ CCD, ~film
• Exposure: photocurrent on C
• Readout: C to V
• (Correlated) Double Sampling
• Cosmetically ‘perfect’
• Little experience

– IBIS1 sensor (1997)

raw image V=∑I(t) I(t)

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• Integrating CMOS APS

– IBIS1 architecture – Larger area: 640 x 480 14µm pixels – ADC – Logic

• Radiation hardening?

– None – Applying known rules would explode chip area

• Chip integration?

– Sensor core unknown – First two-chip prototype

=> Conservative approach: 2 stages Choices

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 11

Phase 1 flow

Two-chip solution: IRIS1 imager with control FPGA Flight demonstration: VMC/IRIS1 on XMM, Cluster-II, … System and chip specification

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Phase 2 flow

IRIS2 single-chip camera IRIS2 electro-optical and radiation characterisation Demonstration microcamera

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Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 14

Camera Specifications

No Yes On-chip line drivers No Yes Power-save Slightly less (ASCoSS: Mv=5) Mv=5 stars Sensitivity CCSDS packets Various parallel and serial IFs SC compatible Interfaces Windowing, subsampling, … Windowing, subsampling, … Readout ??? Tolerant Radiation 8 bit > 8 bit ADC 9Hz 25Hz (video) Frame rate 640x480 > 512x512 Resolution IRIS proposal (technical limits in 1997) Desired

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 15

IRIS Functionality

3 analogue input channels Remote signal sensing 8 programmable output lines Remote control Manual (TC needed); limited automatic control loop Exposure control Start up and take stream of images Autonomous operation Yes Commanded operation RS-485-style ..12.5Mb/s Sync serial ..12.5Mb/s Sync parallel ..3.125MB/s Data interfaces RS-485-style ..3.125Mb/s Sync serial Sync parallel (bus) Command interfaces ESA-style CCSDS TC/TM protocol Full frame ~9Hz Windowed pro rata e.g. 320 x 240 x 36Hz Frame rate Full frame, One window of interest, Y-subsampled 1,2,4,8, X-subsampled 1,2,4,8, X-binned 1,2,4,8, Y-interleaved 1,2,4,8 Readout

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Not Included/Missing

• Image memory

– over 300 kB needed

• Support for external memory

– pin limited

• Synchronous ‘snap shot’ shutter

– requires larger pixel – result: ‘rolling blade’ electronic shutter

=> Imaging rate = output data rate

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 17

IRIS Chip Architecture

640 x 480 pixel array and double sampling column amplifiers Control logic:

• Image sequencer
• I/O interfaces
• CCSDS packetiser

Analogue path:

• Multiplexer
• Amplifier
• ADC

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 18

IRIS Pixel Architecture

• Patented ‘well pixel’ uses bulk of silicon to trap photo-

electrons – Near-100% fill-factor: only metal-covered area is blind – Increased sensitivity – Increased NIR sensitivity: use filter – Risk for inter-pixel crosstalk – Risk for local blooming-like effects

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Typical Application

Packet Telecommand Decoder IRIS Camera-on- a-Chip Data Acquisition System with Memory Thermistor Lighting Pan and Tilt Motor

Sync Serial IF Sync Parallel IF Remote Control Bus Telesense Inputs

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 20

Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 21

IRIS1 Implementation

• Alcatel Microelectronics (Mietec) 0.7µ A/D CMOS

process

• Custom focal plane array
• Existing ADC block

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IRIS1 + FPGA Architecture

IRIS1 analogue ASIC

• Black & white
• RGB colour

(IMEC funded) FPGA

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Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

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IRIS1 Characterisation Results

Few Blemishes and defects

• Operating

temperature

• Latch up
• Radiation
• ADC missing codes

Low sharpness 0.24/0.3 MTF 80mA Power 0.62% Uniformity

• Dark signal at 65°C

31mV/s Dark signal ~40dB post ADC 67dB SNR remarks IRIS1 (analogue)

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IRIS1 Flights (outside contract)

• Visual Monitoring Camera

– Unsollicited IMEC/OIP proposal

• System

– IRIS1 or FUGA15 sensors – Colour or B&W – Actel 1280 FPGA – TTC-B-01 or RS-422 interfaces – Storage for 1 image

• Flights

– XMM – Cluster II – Proba – Mars Express

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IRIS1 Flights (XMM)

Interactive exposure setting IRIS1 Direct readout sensor, No exposure setting

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IRIS1 Flights (Cluster II)

Pre-calculated exposure setting based on solar simulator experiments

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IRIS1 Evaluation

• Performance matched expectations, except
• Low MTF (picture sharpness)

– expected – not to be avoided

• Unless thinner wafer material
• Inter-pixel shielding

– Larger pixels – Less sensitivity

• Limited dynamic range <-> space scenes

– exact pre-calculation of exposure time

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 29

Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 30

IRIS2 Implementation

• Alcatel Microelectronics 0.7µ AD CMOS
• Custom

– FPA (IRIS1 with better output amp) – ADC (same)

• Standard cells

– logic core (subset of library for RT) – I/O pads

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 31

IRIS2 Chip Overview

640 x 480 pixel array 8 bit flash ADC 20 kgates core logic double sampling column amplifiers digital I/O analogue I/O

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 32

IRIS2 Board Specifics

• 84 pin ceramic J-lead package
• Seven 5V power supplies

– can be combined without ill effect

• Requires

– 16 configuration straps – 12 resistors – 13 capacitors – 12.0/12.5MHz clock generator – interface drivers/receivers

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Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 34

IRIS1/2 Characterisation Results

Few Few Blemishes and defects 0 .. 65°C

• Operating

temperature yes

• Latch up

~10 krad

• Radiation

~11

• ADC missing codes
• 0.24/0.3

MTF 74mA 80mA Power 0.52% 0.62% Uniformity 2780mV/s

• Dark signal at 65°C

20mV/s 31mV/s Dark signal 68dB 67dB SNR IRIS2 (mixed signal) IRIS1 (analogue)

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 35

Environmental effects

• Temperature

– increased dark signal

• Radiation

– increased dark signal Limits of operation: 10 krad 65 °C

10krad, 2 sec exposure pre-rad

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IRIS2 Microcamera

• IMEC made demo microcamera

– Not flight standard – Demonstrates most of IRIS2 functionality – Configuration switches inside – Can be extended

• Bus-like backbone
• Tube-like housing
• 8 cameras + 1 ‘station’

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IRIS2 Microcamera Images

Raw imager output

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 38

IRIS2 Microcamera Images

Gamma, Sharpened

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 39

IRIS2 Microcamera Images

IRIS2 raw data, f/4, 700µs exposure ISO100 film, f/4, 1000µs exposure

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IRIS2 Microcamera Images

IRIS2 FF APS 2001 IRIS2 FILM

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 41

IRIS2 Microcamera Images

IRIS2

GSTP/ASCMSA/Integrated Radiation tolerant Imaging System – Final Presentation – ESTEC, 7 March 2001 42

IRIS2 Microcamera Images

ISO 100 FILM

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Overview

• Statement of work: one-chip camera
• Challenges, choices
• Specifications, architecture
• Prototype
• Evaluation
• Final implementation
• Evaluation
• Conclusions and future plans

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Project Evaluation

• Project defined in 1997
• CMOS immature technology

– Low image quality – Radiation issues

=> IRIS2 outdated device in 2001

• FillFactory got experienced in noise-free co-integration of

image sensors with logic

• In-flight experience with IRIS1 drives new developments
• Requests from industry for monitoring chips or cameras

=> Next generation will be better / already is better

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Continuation ASCMSA/IRIS (and ASCoSS) follow-up in STARS3 framework, Work Order 3

• WP1300 Rad-hard imager development (IMEC,FF)
• > 1 MRad attained
• WP2000 Image Compression Camera – IRIS3
• Rad-hard IRIS3 1024x768 chip with integrated control for SDRAM and link

to data compression chip

• Optical InterSatellite Link (beam/star tracker)
• Rad-hard sensor + 10b ADC for beam/star tracking
• 512x512 silicon available now
• 1024x1024 soon

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Conclusions

• Successfully developed single-chip CMOS camera for

space use

• IRIS1 demonstrated in space
• Good electro-optical performance
• Needs better

– MTF/sharpness – Dynamic range – Radiation behaviour

• Solutions in on-going follow-up work