Recently, our team has worked hard to give the CMM a new lease on life, including a visit to Italy’s National Institute of Physics in Turin to train new staff to programme and operate it.

Despite its name, we aren’t using the CMM for measurement. Much like in the ALICE project, it is being used for the precise alignment of chips - this time for a new instrument at GSI’s Facility for Antiproton and Ion Research.

To begin, six chips are manually positioned on a vacuum jig by eye. The machine then uses a camera and micrometre-level movement to adjust each chip into the correct position, a process that takes around 20 minutes per chip.​

With six chips per unit, three units per station and six stations in total, this is a time-consuming and delicate task, even with automation.

Once all six chips are in place, a verification programme confirms their correct alignment before we begin the glueing process. 

An adhesive mask is carefully applied to a flexible printed board (FPCB) using a stencil with precisely cut holes. This ensures that the glue spread on top of the mask only goes where it is needed on the FPCB and avoids areas required later for wire bonding.

Once the mask is removed, the FPCB, with its remaining glue droplets, is aligned over the chips using dowel pins and left to cure overnight.

After inspection, where the chips must be within a 40-micron tolerance, the assembled components are shipped to Germany, where our colleagues at GSI attach the wire bonds. 

So far, two fully bonded working units have been produced, with others waiting at GSI for wire bonding and testing.

This work is led by Paul Morrall from our Nuclear Physics Group and includes mechatronics apprentices Matt and Angelisa. This project also includes collaborators from the University of York.

This science highlight was originally shared on our LinkedIn page. Check out the original post​ to see the photos of the chip alignment process.

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