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Overlay transistors move into microwave region
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ABSTRACTS ON MICROELECTRONICS AND RELIABILITY
Reliability of p l a t ~ 4 h r o u g h holes in muitilayer boards. S. A. DINuzzo and R. H. GAUGER,1966
IEEE Internatio~d Convention Record, Part 9, March 21-25 (1966), p. 106. High density packaging techniques, such as those of microeIectronies, require the use of a compact, high-reliability interconnexion technique. The most promising technique is the use of multilayer interconnexion boards with plated-through holes. This paper gives the results of the accelerated and extended test programmes conducted on multilayer boards that were produced using the plated-through-hole interconnexion technique. Tests were selected specifically to determine the reliability of the interconnexion technique. The results showed that the performance of the multilayer board is limited only by the physical properties of the glass-epoxy board and the current-carrying capacity of the conductors. Muitilayer circuit boards: sharpening an imperfect art. R. W. Konn, Electron. August 8 (1966), p. 141. Multilayer printed circuits are likely to have some flaws, but the boards can be used confidently in high-reliability applications if design and processing controls prevent or catch mistakes. The article describes manufacturing processes and design steps to watch. Through-hole plating processes are also described. Evaluating sealed contacts. P. W. I~ENAUTand T. STATHO$,Bell Labs. Rec., May (1966), p. 155. Sealed contacts are subject to two basic kinds of failures: poor electrical contact, resulting in a high, unstable resistance while the contacts are closed; and failure to release properly. The first condition can occur early in a contact's life because the contact surface is contaminated with foreign matter, or late in its life because the thin, precious metal surface wears through. The surface wears, although the crosspoints do not make or break current, because of minute electric arcs that result when closing contacts discharge the capacitance of the lines to which the contacts are connected. Contacts fail to release if they become bonded together, a condition believed to be mainly caused by cold welding of the precious-metal surfaces. Bell Telephone Laboratories conducts a thorough investigation of the reliability of every proposed improvement in the sealed contact used in the No. 1 ESS. The reliability and long life of the ferreed switch are thus ensured in large measure. Semiconductor device reliability evaluation and improvement on m i n u t e m a n II C ~ . D. R. F ~ - ~ , W. L. GILL and J. R. To~I~soN, Proc. 1966 Electron. Components Conf., Washington DC, p. 389. The Component Quality Assurance Programme (CQAP) was part of the Minuteman II programme which the Autonetics Division of North A~,nericanAviation performed for the U.S. Air Force. This programme at Texas Instruments consisted of stress tests evaluation and improvement of semiconductor devices used in the Minuteman project. This paper discusses the programme performance and results in genera]. Case histories of some of the more important corrective actions are given. Second breakdown and current distributions in transistors. H. A. ScH~r'r and J. C. FRENCH,Solid State Electron. (1966), Vol. 9, pp. 681-688, A study of second breakdown in transistors, which included the use of temperature-sensitive phosphors to reveal current distributions, has indicated that the susceptibility of the transistor to second breakdown is closely linked to the internal distribution of current or of energy dissipation. The effect of such factors as the base drive and i n t e ~ structural irregularities on the internal current distribution is described. A better understanding of the role of the base drive in second breakdown has been achieved. This led to a test which was used to distinguish second breakdown from other low voltage modes that have been reported to be different levels of second breakdown. Overlay transistors move into microwave region, C. Lsr and G. J. GILnv.nT,Electron., March, 21 (1966), p. 93. Continued development of the overlay transistor has extended its high-power capability into the microwave region. An overlay transistor, the 2N4012, can now provide more than 2.5 W as a frequency tripler at an output frequency of 1 Gc/s and has a collector efficiency of 25 per cent or higher. Thus, a single transistor can replace both the varactor mukiplier and the power amplifier now used at L-band frequencies (0.39 to 1.55 Gc/s) for military and industrial microwave eqmpment. In telemetry systems and radio relay, a varactor diode usually performs frequency multiplication. Now, by replacing two devices--the varactor and a conventional amplifier transistor---one overlay transistor will simplify circuit design, reduce the overall space requirement and lower cost.
ABSTRACTS ON MICROELECTRONICS AND RELIABILITY
Reliability of p l a t ~ 4 h r o u g h holes in muitilayer boards. S. A. DINuzzo and R. H. GAUGER,1966
IEEE Internatio~d Convention Record, Part 9, March 21-25 (1966), p. 106. High density packaging techniques, such as those of microeIectronies, require the use of a compact, high-reliability interconnexion technique. The most promising technique is the use of multilayer interconnexion boards with plated-through holes. This paper gives the results of the accelerated and extended test programmes conducted on multilayer boards that were produced using the plated-through-hole interconnexion technique. Tests were selected specifically to determine the reliability of the interconnexion technique. The results showed that the performance of the multilayer board is limited only by the physical properties of the glass-epoxy board and the current-carrying capacity of the conductors. Muitilayer circuit boards: sharpening an imperfect art. R. W. Konn, Electron. August 8 (1966), p. 141. Multilayer printed circuits are likely to have some flaws, but the boards can be used confidently in high-reliability applications if design and processing controls prevent or catch mistakes. The article describes manufacturing processes and design steps to watch. Through-hole plating processes are also described. Evaluating sealed contacts. P. W. I~ENAUTand T. STATHO$,Bell Labs. Rec., May (1966), p. 155. Sealed contacts are subject to two basic kinds of failures: poor electrical contact, resulting in a high, unstable resistance while the contacts are closed; and failure to release properly. The first condition can occur early in a contact's life because the contact surface is contaminated with foreign matter, or late in its life because the thin, precious metal surface wears through. The surface wears, although the crosspoints do not make or break current, because of minute electric arcs that result when closing contacts discharge the capacitance of the lines to which the contacts are connected. Contacts fail to release if they become bonded together, a condition believed to be mainly caused by cold welding of the precious-metal surfaces. Bell Telephone Laboratories conducts a thorough investigation of the reliability of every proposed improvement in the sealed contact used in the No. 1 ESS. The reliability and long life of the ferreed switch are thus ensured in large measure. Semiconductor device reliability evaluation and improvement on m i n u t e m a n II C ~ . D. R. F ~ - ~ , W. L. GILL and J. R. To~I~soN, Proc. 1966 Electron. Components Conf., Washington DC, p. 389. The Component Quality Assurance Programme (CQAP) was part of the Minuteman II programme which the Autonetics Division of North A~,nericanAviation performed for the U.S. Air Force. This programme at Texas Instruments consisted of stress tests evaluation and improvement of semiconductor devices used in the Minuteman project. This paper discusses the programme performance and results in genera]. Case histories of some of the more important corrective actions are given. Second breakdown and current distributions in transistors. H. A. ScH~r'r and J. C. FRENCH,Solid State Electron. (1966), Vol. 9, pp. 681-688, A study of second breakdown in transistors, which included the use of temperature-sensitive phosphors to reveal current distributions, has indicated that the susceptibility of the transistor to second breakdown is closely linked to the internal distribution of current or of energy dissipation. The effect of such factors as the base drive and i n t e ~ structural irregularities on the internal current distribution is described. A better understanding of the role of the base drive in second breakdown has been achieved. This led to a test which was used to distinguish second breakdown from other low voltage modes that have been reported to be different levels of second breakdown. Overlay transistors move into microwave region, C. Lsr and G. J. GILnv.nT,Electron., March, 21 (1966), p. 93. Continued development of the overlay transistor has extended its high-power capability into the microwave region. An overlay transistor, the 2N4012, can now provide more than 2.5 W as a frequency tripler at an output frequency of 1 Gc/s and has a collector efficiency of 25 per cent or higher. Thus, a single transistor can replace both the varactor mukiplier and the power amplifier now used at L-band frequencies (0.39 to 1.55 Gc/s) for military and industrial microwave eqmpment. In telemetry systems and radio relay, a varactor diode usually performs frequency multiplication. Now, by replacing two devices--the varactor and a conventional amplifier transistor---one overlay transistor will simplify circuit design, reduce the overall space requirement and lower cost.