MCM timeline -- evaluation batch

 Here is a summary of MCM testing
Here is the MCM QA procedure
Here is a summary of MCMs whose performance has changed during testing

Here is the idealized version of what we do to each MCM.

  1. upon arrival at LANL, they are visually inspected.
  2. at LANL, glue output cable to MCM with Densil dry adhesive. Toluene primer used. Room temp pressure cure.
  3. send to Pace in CA for surface mount (967-1 ABLESTICK; 80C for two hours), ultrasonic, cold Al wirebonding and encapsulation (dexter hysol EO1061: 85C +/-5C cure for one hour).
  4. at LANL, Surface mount QA. Visual, probe components in search of shorts.
  5. at LANL, QA tests of MCM to evaluate performance.
  6. at LANL, attach silicon detector via kapton cable- Densil dry adhesive, room temp cure. Toluene primer used.
  7. send back to Pace for ultrasonic, cold Al wirebonding and encapsulation (dexter hysol EO1061: 85C +/-5C cure for one hour).
  8. at LANL, test assembly with laser station.
To understand parts of the following section, you need to know how we "grade" MCMs:
  • Grade = A means no problems were found
  • Grade = B means some problems were found, but we will accept the MCM
  • Grade = C means one block of 32 channels does not work
  • Grade = D means two blocks of 32 channels do not work
  • Grade = F means more than two blocks of 32 channels do not work or else the MCM does not work at all

    The dates listed as ?-May-99 mean I am not sure when these things happened, but I believe I have the order correct.

    Here's what really happened to the evaluation lot:

    1. ?-May-99: upon arrival at LANL, they are visually inspected (by Gary Smith).
    2. ?-May-99: at LANL, glue output cable to MCM with Densil dry adhesive. Toluene primer used. Room temp pressure cure.
    3. ?-May-99: send three MCMs (serial numbers 116, 120, 121) to Pace in CA for surface mount (967-1 ABLESTICK; 80C for two hours), ultrasonic, cold Al wirebonding and encapsulation (dexter hysol EO1061: 85C +/-5C cure for one hour).
    4. ?-May-99: First tests of MCM, 1 MCM tested. It did not work. Some surface mount capacitors were mounted backwards, which we eventually discovered when the Ta caps overheated. The caps were the large ones over top of the TGV chips. I believe this was serial #120. Also, some of the surface mount components fell off one or more of the three MCMs.
    5. ?-May-99: "poke-test" (the see how well attached they were) done on remaining surface mount components on three MCMs.
    6. ?-May-99: Three MCMs (serial number 116, 120, 121) sent back to Pace to remove backwards caps and install them correctly. Also, the other 15 MCMs were sent to Pace sometime around this time to have the surface mount components installed for the first time.
    7. ?-May-99: no tests for shorts in surface mount components, but some visual inspection.
    8. ?-May-99: Three MCMs not put through formal QA tests, but all were checked and found OK (serial numbers 116, 120, 121). Assume all qualify as "Grade A" at this time.
    9. 24-Jun-99: at LANL, MCMs 116, 120, 121 attached silicon detector via kapton cable- Densil dry adhesive, room temp cure. Toluene primer used before gluing.
    10. 24-Jun-99(approx): send # 116, 120, 121 back to Pace for ultrasonic, cold Al wirebonding and encapsulation (dexter hysol EO1061: 85C +/-5C cure for one hour).
    11. 8 to 12-Jul-99 at LANL, QA tests of MCM to evaluate performance. These tests include some probing of the MCM test points.
      Grade total number serial numbers
      A 3 112, 118, 119
      B 2 103, 117
      C 4 101, 105, 109, 111
      D 1 114
      F 5 102, 104, 106, 107, 113
      not tested 3 116, 120, 121
      fraction "good": 5/15 = 0.33 (8/18 good if we count #116, 120, 121 good)
    12. 8-Jul-99: MCM#120 sent to Pace to have some surface mount components replaced because they were falling off.
    13. 9-Jul-99: at LANL, MCMs 103, 112, 118 attached silicon detector via kapton cable- Densil dry adhesive, room temp cure. Toluene primer used before gluing.
    14. 9-Jul-99: send back #103, 112, 118 to Pace for ultrasonic, cold Al wirebonding and encapsulation (dexter hysol EO1061: 85C +/-5C cure for one hour).
    15. 20-Jul-99: MCMs 103, 112, 118, 116, 120, 121 (now attached to Si) plus 106 (not attached to Si) sent to Pace to replace 4 surface mount caps. #106 also had a shorted cap which was repaired.
    16. 5 to 9-Aug-99: retested some "bad" MCMs with new Xilinx software:
      Grade total number serial numbers
      A 0 --
      B 0 --
      C 4 101, 105, 109, 111
      D 1 114
      F 4 102, 106, 107, 113
      not tested 9 103, 104, 112, 116, 117, 118, 119, 120, 121
      Net result: no change from previous tests
    17. 6 to 10-Aug-99 (not clear exactly how it overlapped with the tests in previous step): at LANL, probe (many but not all) MCMs for problems with surface mount components. Among these problems were caps on a TGV in #101 and #109 which caused one TGV in each MCM to fail. MCM #107 had cracked epoxy in two places and a missing component. MCM #113 had a short. For more details on tests tests of the surface-mount components, look here.
    18. 11-Aug-99: remaining MCMs 101, 102, 104, 105, 107, 109, 111, 113 114, 117, 119, sent to Pace to have 4 surface mount caps replaced, other known problems in surface mount components repaired (see previous step).
    19. No official QA was done, but #120 was checked and found OK. This was in response to loose surface-mount components noted in surface mount tests (6-10-Aug).
    20. 18 to 19-Aug-99: at LANL, recheck surface mount components on MCMs 101, 107, 109. More shorts found on 107. it is possible that these shorts would have been checked the first time (because it failed a visual inspection). Another interesting detail about 107 is that the shorts over the AMU/ADCs remained even after the surface-mount caps were removed. These shorts seem to be internal. The QA tests show that only the first 32 channels work.
    21. 19 to 25-Aug-99: retested most MCMs:
      Grade total number serial numbers
      A 2 101, 119
      B 1 117
      C 3 105, 111, 116
      D 1 114
      F 6 102, 104, 106, 109, 113, 120
      not tested 5 103, 107, 112, 118, 121
      changes from previous tests:
      101 from grade C to A -- fix in surface-mount short
      109 from grade C to F -- fix in surface mount short fixed bad TGV, but 5 AMU/ADCs failed
      116 from grade A to C -- it is now attached to Si, 4 surface mount components replaced
      120 from grade A to F -- damaged at LANL
    22. 26-Aug-99: at LANL, "gentry spread 5 min epoxy over encapsulate" for 112, 114, 118.
    23. 27-Aug-99 at LANL: Probed surface mount components of 104 (which was OK) and 107 (which showed numerous shorts near the AMU/ADCs). It is possible that these shorts would have been checked the first time (because it failed a visual inspection). Another interesting detail about 107 is that the shorts over the AMU/ADCs remained even after the surface-mount caps were removed. These shorts seem to be internal. The QA tests show that only the first 32 channels work. MCM 116 was also examined (OK?). For some other details about these tests, look here.
    24. 24 to 31-Aug-99(approx): at LANL, test MCM+Si assemblies with laser station.
      MCM#103 (assembly # OB-06) grade B
      MCM#112 (assembly # OB-11) grade D
      MCM#118 (assembly # OB-14) grade A
      MCM#116 (assembly # IB-02) grade C
      MCM#121 (assembly # IB-07) grade A
      changes from previous tests:
      MCM #112 on 8-Jul-99 this no known problems. Now one block of 32 channels plus 24 other channels have failed -- retest with bench cal not yet done. I expect it to fail that test too, but this laser-station test would find problems which would not be seen in bench-cal test. Between these times, the MCM had been attached to Si and also had 4 surface mount components replac8d.

    Here are links to simplified (i.e. a lot of the details about each step are omitted and only steps relevant to the given MCM are included) timelines for individual MCM's which are "bad".

  • MCM 102
  • MCM 104
  • MCM 105
  • MCM 106
  • MCM 107
  • MCM 109
  • MCM 111
  • MCM 112
  • MCM 113
  • MCM 114
  • MCM 116
  • MCM 120

    John Sullivan
    updated 15-Sep-1999