Ashok K. Sharma, Advanced Component Technology Group Leader, Code 562, NASA/GSFC

Background

Hybrid microcircuits and multi-chip modules are used in space flight hardware to save both size and weight.  MIL-PRF-38534 is the basis for procuring these types of parts for space flight use.  MIL-PRF-38534 allows the device manufactures the flexibility of implementing the best commercial practices to the maximum extent possible while providing a product that meets military needs.  Devices compliant to this specification are built in a manufacturing line that is controlled by the manufacturers quality management program.  Class K is the highest reliability level provided for in MIL-PRF-38534 and intended for space applications.  Class H is standard military level in MIL-PRF-38534 specification.

Major Issues

There are 39 manufacturers listed in the current QML, QML-38534-44, out of which only 11 are qualified for Class K, the highest quality level in the specification.  All 39 companies are qualified for Class H, the second quality level.

Manufacturers not listed on the QML may offer space flight level parts.  If they offer an in-house "space level" processing flow, compare it to the MIL-PRF-38534 specification screening, qualification requirements to assure that you are getting adequate quality assurance that is needed to meet your mission requirements.

Make sure that the active and passive (dice or chips) elements used in the hybrid meet the reliability level evaluation for the intended application.

If you have a radiation requirement, total ionizing dose (TID) as well as single event upset (SEU), make sure that the semiconductor and microcircuit dice come from lots tested for radiation levels that are expected for the mission.  In general, rad-hard dice are preferred over rad-tolerant devices.

Not all hybrids are advertised as such, e.g. solid state relays (SSR).  Make sure that they meet the requirements for a hybrid part specification MIL-PRF-38534.

It is recommended that the hybrids should be selected for appliable program class or grade level, with screening and qualification requirements per EEE-INST-002 section M2 Table 1.

Documents and References

• EEE-INST-002: Instruction for EEE Parts Selections, Screening, Qualification, and Derating
• MIL-PRF-38534, Hybrid Microcircuits, General Specification for
• For EIA meeting schedules, go to the EIA web site at www.geia.org for the GI2 committee and to www.jedec.org for the JC13.5 committee.
  

Upcoming Events

• JEDC JC-13.5 Subcommittee: Hybrid, RF/Microwave and MCM Technology: Sept. 8-12, 2003, Columbus, OH.
• EIA G12 Solid State Devices Committee:  They have the same meeting schedule as JC-13.  See the previous line item.
• IMAPS 2003, 36th International Symposium on Microelectronics, November 16-20, 2003, Boston, MA. IMAPS, the International Microelectronics and Packaging Society, is the successor organization to ISHM.
• NASA/DoD Space Parts Working Group, annual meeting in late April/early May