Speaker
Ms
Aneliya Karadzhinova
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
Description
In contemporary high energy physics experiments, silicon detectors are essential for recording the trajectory of new particles generated by multiple simultaneous collisions. To guarantee high sensitivity near the collision point, modern particle tracking systems may feature 100 million channels, or pixels, which need to be individually connected to read-out chains. Silicon pixel detectors are typically connected to readout chips by flip-chip bonding using solder bumps.
The electrical and mechanical quality of the flip-chip interconnects are important for the proper functioning of the particle tracking system in order to minimize the number of dead read-out channels. Furthermore, the detector modules must be robust enough to endure the handling during the installation and the heat generation and the cooling during the operation.
The silicon pixel detector modules were constructed by flip chip bonding 16 readout chips to a single sensor. Eutectic SnPb solder bumps were deposited on the readout chips and the sensor chips had TiW/Pt thin film UBM (under bump metallization). The modules were assembled at Advacam Ltd operating at Micronova Nanofabrication Centre.
We studied the quality and uniformity of the interconnections using Scanning White Light Interferometry (SWLI), stylus profiler and performing destructive pull-strength tests. Furthermore, we compared the results of the characterization of interconnections to those of module performance measurements. According to our results, the Ni/SnPb-TiW/Pt interconnections are excellent for flip-chip bonding pixel detector modules.
Primary author
Ms
Aneliya Karadzhinova
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
Co-authors
Mr
Anton Nolvi
(Department of Physics, University of Helsinki, PO Box 64, 00014, Helsinki, Finland)
Prof.
Edward Haeggström
(Department of Physics, University of Helsinki, PO Box 64, 00014, Helsinki, Finland)
Dr
Eija Tuominen
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
Dr
Ivan Kassamakov
(Department of Physics, University of Helsinki, PO Box 64, 00014, Helsinki, Finland)
Dr
Jaakko Härkönen
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
Dr
Juha Kalliopuska
(Advacam Ltd, Tietotie 3, Espoo, Finland)
Dr
Panja Luukka
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
Dr
Sami Vähänen
(Advacam Ltd, Tietotie 3, Espoo, Finland)
Dr
Teppo Mäenpää
(Helsinki Institute of Physics, PO Box 64, 00014, Helsinki, Finland)
