1. FEI4A Wafer Probing Andrew Stewart 21 September 2012

2. Set-up of semi-automatic wafer probing of FE-I4A wafers near completion. – Cascade S300 probe station added to STControl software. – Reasonable success of achieving a good electrical contact. In a test of probing 6 consecutive die only 1 failed to return test data. – Measurement repeatability at different probe sites looks good (see slides 5 to 11). – Currently use USBpixTestI4 to conduct Global Register, Pixel Register & Sync Scan tests and STControl to conduct Analogue, Digital and Threshold scans. – Would like to use STControl wafer test panel for all tests and automated probing. However, I have encounted a number of issues establishing a full prim list of tests.

3. Issues with wafer panel prim list. – Regulators On: Does this turn on analogue and digital power supplies? Doesn’t appear to work. – How are the GR & PR tests and current readings (I DDD1 etc) accessed? These results don’t appear to be displayed in the Module Analysis panel.

4. Wafer ID:V2AQMLHAnalogue TestDigital Test Chip No. IDDA1 (mA) IDDA2 (mA) IDDD1 (mA) IDDD2 (mA) Global Register Test Pass Pixel Register Test Analogue Pixels with Occ ≠ 200 Digital Pixels with Occ ≠ 200 Mean Threshold Threshold Sigma Comments 11128223.715Yes 981632978575.9 2112632385.6Yes 222254718414.1 3114302293Yes 26854425277243.4Many pixels fail analogue test and threshold scan 4112542382.5Yes 887244073537.7 5910123107.5Yes 209772703na Many pixels fail analogue test. No meaningful threshold scan. 6112592385Yes 2169414694444.3 7112752387Yes 1630711Many pixels fail threshold scan. 8112662484YesNo360913315183250.8 91142323292Yes na V high digital current during PR Test. Analogue & Digital Tests Empty 10na V high current on analogue and digital channels (>0.5A) 11 2492469.9Yes 1743724na Many pixels fail analogue test 12112512492Yes 2678628na Many pixels fail analogue test 1310.726023.486Yes 3262484549446.2 14 15 16 17 1810.324923.777.3Yes 88828594599336Initial Measurement 18 Yes 762 2879 4551322 Measurement after reprobing 19 2011.321823.478.2Yes 202244046461.2Initial Measurement 20 10.3228.823.483.5Yes 188244055446Measurement after reprobing 21 22 23 24159615483801391.9 60244244468344.9 Wafer results spreadsheet. No pass/fail criteria set yet.

5. Repeatability Measurements

6. DieBad Pixels (Analogue) Bad Pixels (Digital) Mean Threshold Sigma Threshold 1888828594599336 18 (Repeat)76228794551322 20202244046461 20 (Repeat)188244055446 Summary of Repeatability Measurements

7. Die 18: Initial Analogue Occupancy Plot (Left) and Analogue Occupancy after re-probing (Right)

8. Die 18: Initial Digital Occupancy Plot (Left) and Digial Occupancy after re-probing (Right)

9. Die 18: Initial Threshold Scan (Left) and Threshold Scan after re-probing (right)

10. Die 20: Initial Analogue Occupancy Plot (Left) and Analogue Occupancy after re-probing (right)

11. Die 20: Initial Digital Occupancy Plot (Left) and Digital Occupancy after re-probing (Right)

12. Die 20: Initial Threshold Scan(Left) and Threshold Scan after re-probing (Right)