Use of high temperature operating life data to mitigate risks in long-duration space applications that deploy commercial-grade plastic encapsulated semiconductor devices
Abstract Commercial-grade plastic encapsulated semiconductor devices are now widely used in space and military equipment for their cost-per-performance and availability advantages over military type ceramic parts. However, many equipment manufacturers still perceive risks in their deployment, and conduct expensive and time-consuming screening and qualification programs to mitigate the potential risks associated with their use. This paper discusses the limitations of the screening and qualification approach currently employed by space equipment manufacturers to assess the long-term reliability of commercially-available plastic encapsulated semiconductor devices (PEDs) in deep space missions. In addition, the paper presents the value of the high temperature operating life (HTOL) data published by manufacturers of PEDs for mitigating the risks associated with the use of such devices in long-duration space applications, where steady-state temperature is the significant stress parameter.
Plastic encapsulated microcircuits (PEMs) in the MIDS program
Smaller availability of military component sources in Europe led to an earlier need to incorporate PEMs in military equipment, including avionics. Processes enabling approval of some non-MIL parts in the design of military equipment have long been used provided that the suitability of parts to their application (including environment) is properly demonstrated. Resulting from the US DOD procurement reform of 1994 (Perry initiative), PEMs were authorized to use in the MIDS terminal design in 1994. MIDSCO's Parts Control Program Plan, was then revised and approved by the IPO to recommend preferably the use of PEMs and of commercial components in the industrial temperature range (-40/spl deg/C, +85/spl deg/C). Thomson-CSF incorporated in its design as many PEMs as practical for the items under its responsibility (receiver/synthesizer SRUs and external power supply LRUs). Thomson-CSF also shared with the other subcontractors the lessons of the "Plan Composants Plastiques" to facilitate the use of these components in the MIDS program, and, slowly, this approach gained acceptance. Currently, Thomson-CSF uses only 2% of MIL parts in its MIDS terminal share. 50% of the non-MIL parts being PEMs. The main key to the success of PEMs in the MIDS program is the success of the design efforts in thermal management and reduction of power dissipation. This made it possible to use these components in the highly demanding environments of uninhabited airborne fighters while staying within the limits of the components specifications with adequate margins and to collect all possible benefits from the use of PEMs.
Reliability Aspects of Plastic Encapsulated Integrated Circuits
The introduction of plastic encapsulated integrated circuits was one of the most significant changes in the semiconductor industry since the development of the integrated circuit itself. While the plastic encapsulation made available low cost-high volume integrated circuits for the industrial and consumer markets, it also introduced a wide range of potential reliability problems. Some of these reliability limitations were recognized and solved early in the development of plastic I/C's while others were of a more subtle nature and took longer to detect and correct. This paper considers the failure modes of plastic encapsulated integrated circuits; the stress tests utilized to detect their presence; the design and process improvements made to eliminate them and presents the results of extensive reliability tests conducted to assess their current reliability status.