Slide 1: Can testers and probe cards keep up with speed requirements for image sensors?
Can testers and probe cards keep up with speed requirements for image sensors? FormFactor Inc. Larry Levy Nobuhiro Kawamata Advantest Corporation. Akira Hamajima
Slide 2: Abstract
Abstract The MIPI alliance has been defining standards for serial interfaces. D-PHY, which was ratified 1.5 years ago supports 1Gbps per lane. The M-PHY specification, whose 1.0 version is about to be ratified, supports about 1.25Gbps/1.5Gbps and has options to support 2.5Gbps/3Gbps and 5Gbps/6Gbps
Slide 3: Contents
Contents • High speed driver • Terms/ Definitions • Standards • Requirements • Tester interconnection and Loss • Probe card interconnection and Loss of 1.3Gbps/3Gbps designs – Probe Head – Probe card board • Follow on works 3
Slide 4: High Speed Drivers
High Speed Drivers Nokia Lumia Icon LG G2 Samsung Galaxy 4S 20 MP camera 12 MP camera 16 MP camera Samsung has put everything it knows about HDTV on brilliant display with the 5.1-inch Full HD Super AMOLED® screen on the Galaxy S5. Movies come to life as they were meant to be seen The large 5.2” Ful
Slide 5: More Data Drives Need for Higher Speed
More Data Drives Need for Higher Speed • Display resolution increasing for video and still – 1080P • In July 2008, the ATSC standards were amended to include H.264/MPEG-4 AVC compression and 1080p at 50, 59.94 and 60 frames per second (1080p50 and1080p60). Source: wikipedia • More Megapixels in came
Slide 6: Terms/ Definitions
Terms/ Definitions • Frame rate: Number of still images that make up one second's worth of video or animation – Frames per second "fps", is a measure of frame rate – The higher the frames per second value, the smoother the video (or animation) will appear • 30fps or faster is typical for smooth vide
Slide 7: MIPI Alliance Standards
MIPI Alliance Standards D-PHY version 1.2 just released at 2Gbps MIPI Alliance web site 7
Slide 8: Mobile Camera Interface
Mobile Camera Interface source: Arasan Chip Systems, Inc. 8
Slide 9: Video Camera RAW Bandwidth
Video Camera RAW Bandwidth iPhone 4/5 Galaxy S4 RED Epix-X1 Camera Image 1920x1080 3264 x 2448 5120x2700 Size Px Mpixel 2.1 8.0 13.8 Gbps @30fps 1.51 5.76 9.95 Gbps @60fps 3.0 (n/a) 11.5 (n/a) 19.9 Gbps @120fps 6.0 (n/a) 23 (n/a) 38.8 CSI-2 D-PHY 4 Lanes CSI-3 M-PHY 4 Lanes unsupported source: Arasa
Slide 10: Display RAW Bandwidth
Display RAW Bandwidth iPhone 4/5 iPad 3 / 4 Galaxy S4 4K tablet1 8K tablet2 Display 960x640 2048x153 1920x108 3840x256 7680x432 Size Px 6 0 0 0 PPI 326 264 441 230 ~700 Mpixel 0.6 3.1 2.1 9.8 ~32 Gbps 0.44 2.27 1.49 7.08 23.89 source: Arasan Chip Systems, Inc. @30fps Gbps 0.89 4.53 2.99 14.16 48 @60
Slide 11: Need for Speed
Need for Speed Are you convinced that we need higher speed? 11
Slide 12: Systematic Approach Required
Systematic Approach Required + = 3Gbps 12
Slide 13: Interconnection Loss Specification in D-PHY
Interconnection Loss Specification in D-PHY • Data rate <=1.5Gbps, loss requirement is less than -2db • Data rate >1.5Gbps, loss requirement is less than -3.75db • Goals: Tester side -1.75db, Probe Card -2db, Total -3.75db loss with 50 Ohm impedance * fh = Data Rate/2 13
Slide 14: Tester Interconnection and Probe Card Goals
Tester Interconnection and Probe Card Goals • -3.75db budget allocates -1.75db to tester, -2db to Probe Card Capture Module Light Source Tester Interconnection HIFIX Cable Performance Board -1.75db Frog Unit Wafer Prober Probe Card Probe Card Board -2 db CMOS Image Sensor Wafer Probe Head 14
Slide 15: Tester Interconnection loss--Action and Results
Tester Interconnection loss--Action and Results • HIFIX Cable: Apply Wide Band Width Cable & Connector • Performance Board: Apply design rule for high speed transmission line • Frog Unit: Improve characteristic over 6Gbps (-0.25db) 2048ch Frog Unit (characteristic (S21)) -0.25db @ 1.5Ghz (*) Figure
Slide 16: Probe Card Loss--- Phase 1 Action and Results
Probe Card Loss--- Phase 1 Action and Results • Design Method PH: LGA between the DUT, MIPI differential pair trace length shortened • Design Rule All: HFTAP high speed transmission line design rule 800Mbps Design 1.2Gbps Design 800Mbps Design 1.2Gbps Design Parallelism 20 64 Probe Head -1.12 to -0.
Slide 17: Probe card loss --- Phase 2 Action and measurement plan
Probe card loss ---Phase 2 Action and measurement plan ▪ Design Method PH: More LGA between the DUT, MIPI differential pair trace ▪ PCB: Trace improvement for differential pair, and back drilling ▪ Design Rule All: New HFTAP high speed transmission line design rule Measurements: PH only, PCB Only, T
Slide 18: Measurement Method and Points
Measurement Method and Points • Measurement: Open ended rise time measurement by TDR 20-80%, 10 measurement points Probe Head Only Probe card (PH+PCB) 18
Slide 19: Probe Card Loss Phase 2 Result S21
Probe Card Loss Phase 2 Result S21 • Well correlated “Probe head only and PCB” and “Total Probe card” loss (Except U36 measurement error) ＰＣＢ ＴＯＴＡＬ PCB + PH U36 ＰＨ ＰＨ ＋ ＰＣＢ Modeled PH + PCB General correlation 19
Slide 20: Probe Card Loss Phase 2 Result S21
Probe Card Loss Phase 2 Result S21 • Loss improved 0.6 to 1.1db Loss 1.2Gbos design -2.84dB to -2.95dB (Except U36) Improved Probe Card Loss 3Gbps Design Target 2dB -1.72 to 2.32dB (Except U36) 20
Slide 21: Probe Card Loss Phase 2 Result TDR
Probe Card Loss Phase 2 Result TDR • Reduced impedance tolerance, less reflection 1.2Gbps Design Pogo : 29.0Ω ～ 35.3Ω Line : 45.8Ω ～ 48.8Ω PCB-PH : 47.4Ω ～ 50.3Ω (MIN） 反射特性が悪化 50.5Ω ～ 53.5Ω (MAX) 3Gbps Design 反射特性が悪化 反射特性が改善 Pogo : 45.2Ω ～ 49.4Ω Line : 52.4Ω ～ 54.9Ω PCB-PH : 45.9 ～ 51.9Ω(MIN) 21
Slide 22: Probe Card Loss Phase 2 Results Summary
Probe Card Loss Phase 2 Results Summary Loss @ F=1.5Ghz Typical Design Rules 3Gbps Design Rules (ie <1.2Gbps) Parallelism 64 64 Total Probe Card S21 Loss -3db* 1.72 to 2.32dB 3Gbps S21 Loss Goal -2db Judgment Fail* Acceptable with minor adjustments Total Probe Card Impedance @ Tr100ps Pogo: 45.2 to
Slide 23: Follow On Works
Follow On Works • Light source keep-out area on PCB reduction by developing LED light source • Advanced Probe Card Material and design rule implementation 23