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Production test and repair of 256K DRAMs with redundancy
World Abstracts on Microelectronics and Reliability weight of 20 ~o polyphenylether fluid and 1 ~o of microcrystalline wax in 1,1,1-trichloroethane.
Power bipolar devices. PHILIPPE LETURCQ. Microelectron. Reliab. 24, 313 (1984). This paper deals with the specific aspects of bipolar device physics and with the problems posed by the design of their structure. Emphasis will be placed on the fundamental mechanisms which determine the on-state, the off-state and the switching performance. A number of relationships between operating characteristics and structure parameters are established. These relationships are useful for improving structure designs. The currenthandling capability of high-voltage transistors is discussed thoroughly as a relevant example. Finally, the state of the art and trends of power bipolar devices are briefly reviewed. Power M.O.S. devices. P. ROSSEL. Microelectron. Reliab. 24, 339 (1984). In this paper, the major structures and electric properties of the relatively new power M O S F E T s are presented. The basic concepts are dealt with first, with a view to increasing the current and voltage capabilities of M.O.S. transistors; and then the way in which they are applied to the so far most promising power structures, i . e . V . M O S and VD.MOS transistors, is shown. The electric properties of these devices are then described, i.e. threshold voltage, voltage current characteristics: ohmic, saturation and quasi-saturation ranges, first and second breakdown, safe operating area. Some dynamic behaviour aspects are also considered. To conclude, one of the fundamental limitations of power M O S F E T s is analyzed, i.e. the on-state resistance vs. voltage handling capability trade-off and some data for comparison with other power devices is also provided. Production test and repair of 256K DRAMs with redundancy. DONALD M. STEWART. Semiconductor Int. 192 (May 1984).
3. C I R C U I T
AND
SYSTEMS
RELIABILITY,
Graphic comparison of three-state device redundancies. KYUNG S. PARK and SUNG S. KIM. Microelectron. Reliab. 24, 461 (1984). The reliabilities of a single three-state device, a system composed of two such devices in series, and that in parallel are compared directly and their respective optimal regions are shown graphically. Switch failure in a two-unit standby system with better utilization of units. L. R. GOEL and PRAVEEN GUPTA. Microelectron. Reliab. 24, 439 (1984). This paper analyses a two-unit cold standby system with three modes and a switching device to put the offline unit into operation. The cold standby starts operating only after it becomes active. When turned on, the transfer switch (TS) operates successfully with fixed probability p(=- 1 - q ) . A single service facility is available to (i) repair a partially or totally failed unit, (ii) repair the failed TS and (iii) activate the cold standby unit. The failure rates are constant, the activation and the repair rates are general. Confidence limits or the failure rate and a rapid projection nomogram for the Iognormal distribution. A. S. JORDAN. Microelectron. Reliab. 24, 101 (1984). In order to predict the sample failure rate from a limited number of early malfunctions, we have developed the rapid lognormal projection n o m o g r a m (RLPN) which we present at 1, 5, and 10yr of service. In the core of each diagram is a family of curves showing the variation of failure rates as a function of sample median life and standard deviation. Superimposed are Arrhenius plots for a series of activation energies, all referenced with respect to a fixed time. We also display the standard deviation as a function of relative median life, using
387
Efficient test/repair of 256K D R A M s requires a high fix-toattempt yield and correct process flow.
Electrical characteristics of large-scale integration silicon MOSFET's at very high temperatures, Part III: modeling and circuit behaviour. F. S. SHOUCAIR,WEI HWANG and PREM JAIN. IEEE Trans Components Hybrids Mfg Technol. CHMT-7, 146 (March 1984). The effects of high temperature (27°C to 300°C) on electrical characteristics of long n and p channel metal-oxide semiconductor field-effect transistors (MOSFET's) are used to extend the validity of the conventional (room temperature) large and small signal models of these devices. A complementary metal oxide semiconductor (CMOS) inverter's transfer characteristics and switching speed performance, and the frequency response of a simple resistive load inverter are presented, with temperature as a parameter. Some implications of the models developed, on analog M O S circuit design (for high-temperature operation), are discussed. Detection and accelerated testing of vibration-induced connector wear. HENRY S. BLANKS. IEEE Trans Components Hybrids Mfg Technol. CHMT-7, 3 (March 1984). Voltage drop and contact resistance, especially when the connector test, are very insensitive to vibration-induced plating damage in connectors. The spectral analysis of the voltage drop, while the two members of the connector are undergoing relative sinusoidal micromotion and passing dc current, provides much more sensitive detection of wear and information about its extent. Monitoring the spectral content while increasing the vibration amplitude linearly with time is a potentially useful accelerated vibration life-test, although its quantitative application to the prediction of connector life for other vibration profiles is still uncertain. Gold-plated, finplated, and rhodium-plated printed circuit board edgecontacts, mating with commercial gold-plated socket contacts, have been investigated, with vibration parallel to the board fingers.
MAINTENANCE
AND
REDUNDANCY
cumulative failure as a parameter. The R L P N provides graphical means to estimate the failure rate at the planned service life and operating temperature in an efficient manner from the time to failure at the aging temperature and sample size for known or assumed values of the standard deviation and activation energy. To obtain the confidence limits for the failure rate of the lognormal distribution at the 90 ~ confidence level, we have derived an approximate formula that relates the bounds to the service life and the sample's size, median life, and standard deviation. Then, by an appropriate selection of the independent variables and parameters, the confidence intervals are displayed as a series of curve families. The applications of the diagrams are discussed by means of illustrative examples taken from the field of GaAs FETs.
Selection factor algorithm for reliability and maintainability tradeoff to optimize availability allocation subject to cost constraint. K. K. GOVIL. Microelectron. Reliab. 24, 411 (1984). A new simplified algorithm is given for optimum availability allocation subject to cost constraint. The algorithm is applicable to a series structure (1-out-of-k: F). The algorithm employs fixed cost increments and computation of selection factor for each subsystem. The cost increment is allocated to that subsystem which has the highest value of the selection factor. It now becomes possible to directly trade off reliability for maintainability or vice versa in practical design. A two-unit deteriorating standby system with inspection. L. R. GOEL and PRAVEEN GUPTA. Microelectron. Reliab. 24, 435
Power bipolar devices. PHILIPPE LETURCQ. Microelectron. Reliab. 24, 313 (1984). This paper deals with the specific aspects of bipolar device physics and with the problems posed by the design of their structure. Emphasis will be placed on the fundamental mechanisms which determine the on-state, the off-state and the switching performance. A number of relationships between operating characteristics and structure parameters are established. These relationships are useful for improving structure designs. The currenthandling capability of high-voltage transistors is discussed thoroughly as a relevant example. Finally, the state of the art and trends of power bipolar devices are briefly reviewed. Power M.O.S. devices. P. ROSSEL. Microelectron. Reliab. 24, 339 (1984). In this paper, the major structures and electric properties of the relatively new power M O S F E T s are presented. The basic concepts are dealt with first, with a view to increasing the current and voltage capabilities of M.O.S. transistors; and then the way in which they are applied to the so far most promising power structures, i . e . V . M O S and VD.MOS transistors, is shown. The electric properties of these devices are then described, i.e. threshold voltage, voltage current characteristics: ohmic, saturation and quasi-saturation ranges, first and second breakdown, safe operating area. Some dynamic behaviour aspects are also considered. To conclude, one of the fundamental limitations of power M O S F E T s is analyzed, i.e. the on-state resistance vs. voltage handling capability trade-off and some data for comparison with other power devices is also provided. Production test and repair of 256K DRAMs with redundancy. DONALD M. STEWART. Semiconductor Int. 192 (May 1984).
3. C I R C U I T
AND
SYSTEMS
RELIABILITY,
Graphic comparison of three-state device redundancies. KYUNG S. PARK and SUNG S. KIM. Microelectron. Reliab. 24, 461 (1984). The reliabilities of a single three-state device, a system composed of two such devices in series, and that in parallel are compared directly and their respective optimal regions are shown graphically. Switch failure in a two-unit standby system with better utilization of units. L. R. GOEL and PRAVEEN GUPTA. Microelectron. Reliab. 24, 439 (1984). This paper analyses a two-unit cold standby system with three modes and a switching device to put the offline unit into operation. The cold standby starts operating only after it becomes active. When turned on, the transfer switch (TS) operates successfully with fixed probability p(=- 1 - q ) . A single service facility is available to (i) repair a partially or totally failed unit, (ii) repair the failed TS and (iii) activate the cold standby unit. The failure rates are constant, the activation and the repair rates are general. Confidence limits or the failure rate and a rapid projection nomogram for the Iognormal distribution. A. S. JORDAN. Microelectron. Reliab. 24, 101 (1984). In order to predict the sample failure rate from a limited number of early malfunctions, we have developed the rapid lognormal projection n o m o g r a m (RLPN) which we present at 1, 5, and 10yr of service. In the core of each diagram is a family of curves showing the variation of failure rates as a function of sample median life and standard deviation. Superimposed are Arrhenius plots for a series of activation energies, all referenced with respect to a fixed time. We also display the standard deviation as a function of relative median life, using
387
Efficient test/repair of 256K D R A M s requires a high fix-toattempt yield and correct process flow.
Electrical characteristics of large-scale integration silicon MOSFET's at very high temperatures, Part III: modeling and circuit behaviour. F. S. SHOUCAIR,WEI HWANG and PREM JAIN. IEEE Trans Components Hybrids Mfg Technol. CHMT-7, 146 (March 1984). The effects of high temperature (27°C to 300°C) on electrical characteristics of long n and p channel metal-oxide semiconductor field-effect transistors (MOSFET's) are used to extend the validity of the conventional (room temperature) large and small signal models of these devices. A complementary metal oxide semiconductor (CMOS) inverter's transfer characteristics and switching speed performance, and the frequency response of a simple resistive load inverter are presented, with temperature as a parameter. Some implications of the models developed, on analog M O S circuit design (for high-temperature operation), are discussed. Detection and accelerated testing of vibration-induced connector wear. HENRY S. BLANKS. IEEE Trans Components Hybrids Mfg Technol. CHMT-7, 3 (March 1984). Voltage drop and contact resistance, especially when the connector test, are very insensitive to vibration-induced plating damage in connectors. The spectral analysis of the voltage drop, while the two members of the connector are undergoing relative sinusoidal micromotion and passing dc current, provides much more sensitive detection of wear and information about its extent. Monitoring the spectral content while increasing the vibration amplitude linearly with time is a potentially useful accelerated vibration life-test, although its quantitative application to the prediction of connector life for other vibration profiles is still uncertain. Gold-plated, finplated, and rhodium-plated printed circuit board edgecontacts, mating with commercial gold-plated socket contacts, have been investigated, with vibration parallel to the board fingers.
MAINTENANCE
AND
REDUNDANCY
cumulative failure as a parameter. The R L P N provides graphical means to estimate the failure rate at the planned service life and operating temperature in an efficient manner from the time to failure at the aging temperature and sample size for known or assumed values of the standard deviation and activation energy. To obtain the confidence limits for the failure rate of the lognormal distribution at the 90 ~ confidence level, we have derived an approximate formula that relates the bounds to the service life and the sample's size, median life, and standard deviation. Then, by an appropriate selection of the independent variables and parameters, the confidence intervals are displayed as a series of curve families. The applications of the diagrams are discussed by means of illustrative examples taken from the field of GaAs FETs.
Selection factor algorithm for reliability and maintainability tradeoff to optimize availability allocation subject to cost constraint. K. K. GOVIL. Microelectron. Reliab. 24, 411 (1984). A new simplified algorithm is given for optimum availability allocation subject to cost constraint. The algorithm is applicable to a series structure (1-out-of-k: F). The algorithm employs fixed cost increments and computation of selection factor for each subsystem. The cost increment is allocated to that subsystem which has the highest value of the selection factor. It now becomes possible to directly trade off reliability for maintainability or vice versa in practical design. A two-unit deteriorating standby system with inspection. L. R. GOEL and PRAVEEN GUPTA. Microelectron. Reliab. 24, 435