**Pixel Modules**

There are 1744 modules in the pixel detector. A schematic view of a
barrel pixel module is shown in Figure M1 and a picture of a disk pixel
module in Figure M2. A pixel module consists of the following
components:

-   a sensor tile 63.4 x 24.4 mm^2^, about 250 microns thick

-   16 front-end electronics chips, each with 2880 electronics channels

-   bump bonds (PbSn or In) that connect the electronics channels to
    pixel sensor elements

-   a copper-on-kapton flexible printed circuit board (flex-hybrid)

-   a module-control-chip (MCC) attached to the flex-hybrid

-   copper-on-kapton pigtail with connector (barrel modules) or a
    micro-cable (disk modules) connected to the flex-hybrid

![](media/image1.png){width="3.84375in" height="3.5104166666666665in"}

Figure M1 A schematic view of barrel pixel module.

Sensor tiles and electronics chips are connected by bump bonding
technology to form bare modules. Both solder(PbSn) and indium bump
technologies were used to make pixel modules. The production statistics
of bare modules are summarized in Table M1.

  ----------------- ----------------- ----------------- -----------------
                    In                PbSn              Total

  Assembled         1468              1157              2625

  Accepted          1296              1122              2418

  Rejected          172               35                207
  ----------------- ----------------- ----------------- -----------------

Table M1 Summary of production bare modules.

The number of accepted modules includes reworked modules (13% for In and
8% for PbSn) in which a faulty front-end chip was removed and replaced.

![](media/image2.png){width="5.333333333333333in"
height="1.8819444444444444in"}

Figure M2 A picture of a pixel disk module.

Flex hybrids with attached and tested MCC chips were glued to accepted
bare modules. Losses occurred during this step, leaving 2312 modules for
electrical and final mechanical characterization.

Pixel modules were ranked according to electrical testing and mechanical
criteria. Extensive electrical testing was done at room temperature and
at -10^o^C, approximately the operating temperature. Thermal cycling was
performed on each module prior to completion of electrical testing. The
ranking also took into account repair procedure (wire bond replacement
or other) and other features. The ranking procedure was used to separate
the modules into those acceptable for the B-layer r(highest quality) and
for the outer barrel and disk regions. Modules with the best ranking
were loaded on barrel staves and disk sectors, leaving modules with the
poorest ranking as spares. A brief summary of the yields and ranking
after testing is given in Table M2.

  ---------------------- --------- ------ --------- ------ --------- ------
                         In               Solder           Total     

                         Number    \%     Number    \%     Number    \%

  Assembled              1190             1122             2312      

  Accepted               1025      86.1   1075      95.8   2100      90.8

  B-layer quality        281       23.6   445       39.7   726       31.4

  Not B-layer quality    744       62.5   630       56.1   1374      59.4

  Rejected               165       13.9   47        4.2    212       9.2
  ---------------------- --------- ------ --------- ------ --------- ------

Table M2 Summary of yield and ranking of tested pixel modules.