Construction and Status of the Origami Module Prototype C. Irmler, M. Friedl HEPHY Vienna

23rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Contents SuperSVD & Origami Concept APV25 Thinning Origami Hybrid Module Assembly Open Issues Summary Outlook

33rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 SuperSVD Layout Tentative geometry  optimization is underway New central pixel double-layer using DEPFET (see PXD session) 4 strip layers of 6” DSSDs (see talk by M. Valentan) Every sensor is read out individually to maintain good SNR –red:Origami chip-on-sensor concept –green:read out by conventional hybrid Double-layer of DEPFET pixels 4 layers of double- sided strip sensors

43rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Origami Chip-on-Sensor Concept Thinned APV25 with flex circuit (Kapton) sits on sensor Providing shortest possible connections to the strips  high SNR (drawing not to scale)

53rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Sketch of the Outermost Ladder (Layer 6) Composed of 5 x 6” double-sided sensors Center sensors have Origami structure Border sensors are conventionally read out from sides Cooling block (end ring) Connector (Nanonics) Structural element (Zylon) Cooling pipe Flex circuits Electronics for border sensor ca. 60cm

63rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 APV25 Thinning One wafer (319 good dies) thinned down from 300 µm to 106 µm and diced by French company EDGETEK / WSI Received 314 good dies (5 lost = 98.4% yield) 16 thinned APVs mounted onto 4 hybrids Compared to 1 hybrid with 4 standard APVs Measurement Results: All APVs show similar signal and noise figure Proper calibration curve No measurable differences between normal and thinned chips  Thinning has no effects on APV functionality and signal quality! APV25 Calibration Curve Thinned APV25 Standard APV25

73rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Origami Hybrid – Final Layout 4 n-side APV chips 2 p-side APV chips Connectors (on both sides) Flex fanouts to be Wrapped around the sensor edge 3-layer flex hybrid design p- and n-sides are separated by 80V bias n-side pitch adapter is integrated in hybrid Animal farm (mascots of creators)

83rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Origami Hybrid - Flexes 3 pcs. of each type ordered at CERN PCB workshop in Feb. 09 Delayed reception of parts: –Hybrid: 22 April –Fanouts: 6 June Module assembly started very late at 10 June. Not enough time to finalize module before Belle II GM However, assembly is in progress

93rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Origami Hybrid – PCB Quality We faced some problems –A couple of bad vias (cured by soldering thin wires) –Some bad integrated fanouts (see photo below) –Bad bondability of the integrated fanout Good Bad

103rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 1 Gluing fanouts onto bottom side Custom jig (porous stone inlay) for gluing and wire bonding Two component epoxy paste adhesive Araldite® 2011 Microscope used to align fanouts against sensor and hybrid Distance between flexes is important SVD 3 Hamamatsu DSSD top side: 152 µm pitch (z) bottom side: 50 µm pitch (rφ)

113rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 2 APV25 chips are glued onto the Hybrid Two component conductive adhesive Alignment under microscope Steps 1 & 2 can be performed in parallel

123rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 3 Wire bonding between fanouts and sensor Fully automated bonder F&K Delvotec 6400 Processing of bottom side is finished everything worked fine

133rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 4 Gluing hybrid onto Rohacell foam (can be done in parallel with step 3) Rohacell held by vakuum Hybrid is kept up by tape 1.Cutting out Rohacell 2.Applying glue 3.Placing hybrid onto Rohacell 4.Adjustement 5.Putting weights to keep flat There must be sufficient glue underneath bond pads!

143rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 5 Flip sensor and fanouts Using another jig  jig2 Jigs are stuck together with 3 alignment pins Connect jig2 to vacuum Turning over Plug off vacuum from jig1 Remove jig1 Further assembling has to be done on jig2 Fanouts are more rigid than expected We bent and fixed them in order to force their final form 2 openings to protect bottom side bond wires

153rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 6 Wire bonding of APV25 power and control lines Electrical test of hybrid –some bad vias –repaired with thin wires –one APV with I2C failure Hybrid PCB design is okay 7 of 8 APV chips are working well Excellent internal calibration results bottom APV25 top APV25 APV25 calibration curves of Origami hybrid

163rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 7 Gluing the hybrid onto top side of sensor Aligning pitch adapter to strips on sensor We also tried to bend the fanouts and checked their alignment –seems to be okay –probably a mechanical tool for alignment and gluing of fanouts will be necessary –softer fanouts for SVD production preferable –single layer design by other company (Casio?)

173rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 8 Until this point there were no problems which could not be solved Next task: connecting Origami to sensor by wire bonding –No matching bond parameters could be found –Bonds on integrated pitch adapter didn’t attach Possible Reasons: –To little glue underneath the bond pads? –Bad gold coating of pads? –... something else? –Has to be investigated! –It already worked well with the Flex-Module in 2006 Workaround: –We checked the bondability of the pitch adapter of another Origami sample  seemed to be OK –We cut it out, glued it onto the integrated one and tried to bond again

183rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 8 continued Yesterday evening we received really bad news from Vienna: –A corner of the sensor was broken during the second bonding attempt. –We actually do not know the reason for this accident. –Was the sensor weakened by too many attempts to bond at the same location in order to find working parameters? –Malfunction of the bonding machine? Usually it stops automatically when anything goes wrong. –… something else? Anyway, this module is damaged and can not be finalized  R.I.P. We have to investigate the reasons once we are back in Vienna.

193rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 8 continued Photos of the broken sensor:

203rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly – Open Issues Bonding of sensor and hybrid – principal bondability proven after the accident (see photo below) Bend and glue the fanouts onto the top side of the module Connect the APV frontend with the pitch adapters by wire bonds We will use the damaged module for tests of the above tasks Mounting of cooling pipe and support structure Mechanical frame for beam test

213rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 First attempt to assemble an Origami module After delayed delivery of flexes, assembly has only been started on 6 June Good progress since then Some issues with quality of flexes –A couple of bad vias –Some cases of bad integrated fanouts –Bad bondability of the integrated fanout –We shall receive new and hopefully better samples within the next two weeks from the CERN workshop Accident during bonding  sensor is broken We have to restart from the beginning… Summary

223rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Outlook We don’t give up!

233rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 BACKUP SLIDES

243rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Origami Hybrid – Flexes 2

253rd Open Meeting of the Belle II Collaboration, C. Irmler8 July 2009 Module Assembly Step 7a