Assembly and bonding procedures

First prototype

The first prototype features a squared PANDA CIS sensor which is read-out every second strip. The assembly of the prototype was performed at the Detector Laboratory at GSI.

List of the components used:

• 2 L-boards for large sensors (version Sensor-Board APV Rev.1.0 HISKP 02/2012)
• 1 large squared sensor (type spssdm65 or S2), lot 310344, wafer 14
• 2 flexible pitch adapters (PA) for two APVs (256 channels), 130um pitch (type Pitch-Adapter 2APV-130µm, ID n. 19)
• 4 front-ends APV25-S1

The following procedure was followed:

• glueing of the PA on the PCB, using cyanoacrylate glue. The PA is aligned to the markers on the board. The procedure is repeated on the second board.
• glueing of APVs on the PCB using bi-component conductive glue. APVs are aligned to the pads on the PA. Only two APV per sensor are used, because of the 130um readout scheme (half of the strips on the sensor are left unconnected). The procedure is repeated on the second board.
• glueing of the sensor on one board using bi-component non-conductive glue. The PA is aligned to the pads of the PA and therefore only partially to the white markings on the PCB.
• curing of the glue (approximately one night at 50°C).
• glueing of the sensor on the other board. Glueing of the two boards together, without mechanical spacers. The assembly is now complete.
• curing of the glue
• Wire bondings:
  • APV <-> PCB (front-end): 18 bonds (VDD, VDD/2 and GND)
  • APV <-> PCB (back-end): 28 bonds (I/O signals)
  • APV <-> PA: 128 bonds arranged in two loops
  • PA <-> Sensor: 256 bonds per side (all the pads on the PA are used; half of the strips on the sensor are used)
  • Sensor - Bias pads on PCB:
    • n-side: the bias ring on the sensor is connected to the HV+ pad
    • p-side: the guard ring on the sensor is connected to the GUARD pad and the bias ring is connected to the BIAS pad

The bonding scheme is summarized in this document. The biasing scheme of the sensor board is shown here.

Gallery of details of the wire bondings (click to view larger):

Pictures of the complete prototype (click to view larger):

(n-side of the sensor is visible)

(p-side of the sensor is visible)

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-- TommasoQuagli - 26 Sep 2012