Difference: PitchAdaptor (1 vs. 2)

The Glasgow group has developed a system to fabricate Aluminium tracks on glass substrates to be used a pitch adaptors.

The masks are designed in Physics and Astronomy using LEdit with the use of LEdit Macros that allow the dimensions of the adaptors to be defined such that the mask can be designed in a very short amount of time. The typical pitch adaptor has been designed to match our three chip Beetle hybrid and has 3 sets of 128 strips. The adaptor also has extra strips to carry HV and HV return to the detector.

The masks are written in the Electrical Engineering Department's JWNC using e-beam lithography. The maximum mask size that we have written to date is 5inch for a 4 inch wafer.

Photo-lithography is used to transfer the mask design to wafers of glass (we use 300micrometer thick glass from Schott).

Aluminium is sputtered onto the glass and lift-off is used to realise the design. This whole process is performed in the JWNC.

The wafer is tested in Physics and Astronomy on our Cascade probe station and with the use of Keithley and HP test equipment. The Keithley controls the stepper motors of the probe station such that a whole wafer with 2688 strips can be probed in less than 1 day. The tests performed are electrical resistance measurements between neighbouring strips to detect shorts between strips and capacitive measurements between neighbouring strips to detector breaks in the strips.

Several designs have been realised which are compatible with detectors of pitches of 80 and 50 micrometer.

Further work is progressing to develop AC coupled pitch adaptors to allow testing of DC coupled detectors.