IB stave assembly A. Di Mauro, C. Gargiulo, J. Van Beelen ITS-MFT mini-week

TDR procedure 12/03/20142ITS-MFT mini-week - IB stave - A. Di Mauro Main steps: HIC assembly + HIC gluing on C-fibre support

TDR procedure HIC assembly by laser ball soldering – Tooling: vacuum table (A) to hold chips (with x,y,z micrometric adjsutment), vacuum table (B) to hold FPC, soldering macor grid with conical holes ( ), ball pick-up 12/03/20143ITS-MFT mini-week - IB stave - A. Di Mauro A B A B INFN BARI

HIC assembly by laser ball soldering 1.Nine chips are placed above the vacuum table A and precisely aligned with respect to each other 2.The FPC is placed above the vacuum table B and held in a position defined by reference pinholes 3.The FPC is aligned with respect to the subjacent array of chips by matching the holes with the connection pads on the chip surface 4.The soldering grid, aiming to gently press the FPC against the chip, is placed above the stack-up and aligned with respect to the holes in the FPC 5.The loaded ball pick-up tool is aligned above the stack-up corresponding to the first chip and overlapped to the soldering grid; then the balls are released 6.The laser soldering of each connection is performed in sequence 7.The last four steps are repeated to connect all remaining chips and complete the HIC 8.Electrical tests and metrology of chips positions 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro4 TDR procedure

HIC gluing on C-fibre support – No details were provided 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro5 TDR procedure

Procedure update Optimization of laser soldering – Insulation of chips from aluminium vacuum table (acting as heat sink) using a thin macor plate – Soldering under N 2 /H 2 (95/5) mixture + gas exhaust holes – Soldering under vacuum 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro6

Procedure update 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro7 gas exhaust hole Solder mask Chip Polyimide Copper Solder mask Ball Ø 200 µm +/- 8 µm Hole Ø 200 µm ± 10 µm FPC pad Ø 400 µm + (10 to 16 µm) FPC antipad Ø 600 µm + (10 to 15 µm) 10 µm 25 µm 50 µm 25 µm 10 µm 50 µm

Procedure update 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro8 Soldering under vacuum Advantages wrt to N 2 /H 2 : -No exhaust holes -Environmental conditions for soldering: faster and reproducible

Further considerations (apparently not inter- correlated): Al sputtering done in batches of 50x150 cm: try to maximize no. of FPCs fitting in such a surface Safe handling of HIC during all phases Ensure repeatability of chips alignment FPC holes’ position accurate “enough”, spread compensated by larger chip pads (to be verified) 12/03/20149ITS-MFT mini-week - IB stave - A. Di Mauro Procedure update

Al-FPC layout under study 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro10 -Double no. of FPCs in each foil -Easier cutting of extra material (wings) at the end of stave assembly

FPC/HIC frame 12/03/ Frame holding FPC from soldering until stave assembly: easier handling possible protection with additional lids The frame (FPC) has pinholes (targets) to be used as reference for placement/alignment during the various phases The same pinholes (or additional ones) match pinhole in the C-fibre connectors

Reviewed procedure 1)Mount FPC on frame using reference pinholes 2)Place chips on vacuum table and align with respect to reference pinholes (on table) matching those of the frame 3)Overlap soldering grid to FPC 4)Release soldering balls inside the grid using the pick-up tool (for all chips) 5)Fix lid and start vacuum 6)Laser soldering of 9 chips 7)Electrical test + metrology of HIC (final position of chips wrt to frame pinholes) 8)Glue HIC on C-fibre support using jig with pinholes in connectors 9)Final metrology to transfer chips position to external target (details to be worked out) 12/03/2014ITS-MFT mini-week - IB stave - A. Di Mauro12