HPK FPIX & BPIX sensor research summary at Purdue E. Alagoz 1, M. Bubna 1, A. Krzywda 1, K. Arndt 1, D. Bortoletto 1, I. Shipsey 1, G. Bolla 1, S. Kwan 2, I. Osipenkov 3 1 Physics Department, Purdue University, West Lafayette, IN, USA 2 Fermi National Accelerator Laboratory, Batavia, IL, USA 3 Texas A&M University, TX, USA 15 June 2012

Received FPIX and BPIX sensors HPK FPIX & BPIX sensors All IVs T = 21 °C for sensor quality check

PROBE STATION IV TESTS OF BARE HPK T = 21 °C

IV measurement scheme BPIX IV scheme   FPIX IV scheme

FZ200N IVs FPIX FZ200N  V breakdown ~ 450 V (all FPIXF sensors) V breakdown ~ 850 V (all FPIXE sensors)  BPIX FZ200N V breakdown ~ 1000 V

FPIX MCZ200P IVs V breakdown ~ 600 V (all FPIXF_1 sensors) V breakdown ~ 750 V (all FPIXF_2 sensors) 06_FPIXF_1: no breakdown below 1000 V

BPIX MCZ200Y IVs No breakdown below 1100 V

FPIX FZ320P IVs V breakdown ~400 V Was this expected?

BPIX FZ320Y IVs V breakdown ~950 V

Summary & observations 52 HPK FPIX & BPIX sensors received All sensor IVs T = 21 °C IV data uploaded to CMS database via BigBrowser Fluctuations observed in IVs: possible reason can be poor contact between sensor and the probe chuck due to sensor non-flat back surface Different breakdown voltages observed for MCZ200P FPIX and FZ200N FPIX sensors Sensors will be sent for bump bonding at Princeton

BUMP BONDING

Bump-bonding Processing at Princeton University Bump-bond solder material is indium No reflowing applied, just mechanical pressure applied after solder deposition to ROC bump-bond pads UBM for silicon bump-bond pads Varying silicon-to-ROC interface clearance but 8 μm clearance reported by Princeton staff 5 prototypes produced so far

Spark area in the ROC Spark area in the Sensor First bump bonded prototype Sensor (HPK_FZ_200N_06_BPIXA_1) arced below -300 V Bump bonding: First prototype

Edge passivation HPK sensor coating With Parylene (N-type) at room temperature at the Purdue Birck Nanotechnology Center 280 V insulation per micron expected

Edge passivation Bump bonded prototypes glued and wire bonded to on daughter cards on PCB test boards Checked ROC functionality and sensor IV before coating Coating applied to the whole assembly for simplicity and to avoid masking ROC wire bond pads sensor HV pad on the backplane Two HPK and three FPIX bump bonded sensors in the CVD chamber PCB Daughter card sensor

First MCZ prototype passivation Sensor (HPK_MCZ_200Y_07_BPIXD_1) arced at -575 V Spark area in the sensor Spark area in the ROC Coating: 2 um thick parylene

Two more MCZ 200P FPIX type HPK sensors were coated with 4 micron Parylene to achieve 1000 V with no arcing present assuming 280 V per micron of Parylene coating Both samples tested up to 800 V No arcing observed Readout chip functionalities are same as before coating Parylene works well for passivation Coating: 4 um thick parylene

SEM images taken for the sensor arced at 575 V after being coated with 2 micron thick Parylene A good coating uniformity observed Coating distributed everywhere on the sensor Coating: 4 um thick parylene silicon Parylene coating

Coating: 4 um thick parylene Non-flat plateau and increase in IV after coating needs to be investigated

Coating: 4 um thick parylene Non-flat plateau and increase in IV after coating needs to be investigated

Bump bonding summary 5 sensors bump bonded (2xFZ200N, 3xMCZ) First prototype burned due to arching Second prototype: ROC did not work at all No serious ROC test before bonding 3 more prototype (2x MCZ 200P and 1x FZ200N types) 1 MCZ200Y BPIX sensor tested in the beam test 90% tracking efficiency with rotation Coated with 2 μm thick Parylene Arcing observed at 575 V 2x MCZ200P FPIX sensor Coated with 4 μm thick Parylene No arcing observed up to 800 V 1 prototype ROC is still functioning out of 5

Next Request Princeton to bump bond the rest of the sensors and send to Purdue Send additional sensors at FNAL and Purdue to Princeton No pre-assembling/no pre-coating testing Mask ROC wire-bond pads and sensor HV pad with Sylgard 186 silicone rubber or something similar Apply coating of 8 μm thick Parylene (2000 V insulation) Unmask ROC wire-bond pads and sensor HV pad Glue and wire bond coated prototypes to PCB test boards No daughter card will be used Checked post-coating ROC functionality and sensor IV Check yield of bump-bonding and coating processes

Sent to Princeton 12x MCZ 200P FPIX 12x MCZ 200Y BPIX 1x FZ200N FPIX 1x FZ200N BPIX Sent to FNAL 8x FZ200N BPIX 7x FZ200N FPIX Left at Purdue 1x FZ200N BPIX 2x FZ200N FPIX 4x FZ320Y BPIX 4x FZ320 FPIX Final inventory Bump bonded 3x MCZ 200P FPIX 5x MCZ 200Y BPIX 1x FZ200N FPIX 1x FZ200N BPIX