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Particle control in high-current ion implanters
898
World Abstracts on Microelectronics and Reliability
A comparison between noise measurements and conventional electromigratiou reliability testing. J. G. COYrLE, T. M. CriEs and K. P. RODBELL. Proc. IEEE/IRPS, 203 (1988). The observed sensitivity of noise measurements to electromigration damage in metal films suggests that they be used as a non-destructive test for measuring thin film interconnect reliability. This paper reports the results of experiments designed to compare conventional median-time-to-failure (MTF) data with those obtained through the use of noise measurements. Comparisons are made on aluminum and aluminum-copper alloy films from identical wafers fabricated with varying electromigration-sensitive parameters. Application of copper conductor and ruthenium containing oxides-glass resistor to high-frequency hybrid ICs for a portable cellular radio. TOSHIO OGAWA. MITURU FUJII, TADAMICHI ASA1, AKIRA IKEGAMI and TAKAE KOBAYASHI. IEEE Trans. Compon. Hybrids m)~7 Technol. 11, 211 (1988). Interest in thick-film copper hybrid ICs with resistors for high frequency use has increased considerably during the past few years. Technical uncertainties are being resolved and the potential advantages of the copper-conductor thickfilm system are being recognized. This paper presents an assessment of a copper-conductor and resistor system and its performance in a high-frequency hybrid application. Resistance of the copper-compatible resistor, containing RuO2, increases after retiring over 600°C and drastically increases as the firing temperature is raised. The cause of this resistance change was examined. Scanning-electron micro-
9. E L E C T R O N ,
ION
AND
Ultra-low dielectric constant porous silica thick films for high-speed IC packaging. UMAR MOHIDEEN,T. R. GURURAJA, LESLIE E. CROSS and RUSTUM RoY. IEEE Trans. Compon. Hybrids mr9 Technol. II, 159 (1988). Interconnect systems which are required in high-speed GaAs digital ICs use stripline techniques for signal traces which must be deposited over very low dielectric constant substrates. Materials with relative dielectric constant k less than 3 and having low-loss tangents up to microwave frequencies are required for ceramic materials. Such values are impossible to achieve in single-phase ceramic monoliths and composite approaches are necessary. A technique for preparing porous silica films of thickness 1 to 10 ~m is presented. The dielectric constants of these films are in the range of 2.4 to 2.8 with a loss tangent less than 0.005 at l kHz.
LASER
Troubleshooting ion implantation processes. CHARLES B. YARLING and W. ANDREW KEENAN. Semiconductor int., 164 (May 1988). A reliable and accurate approach to testing and process control allows process engineers to quickly pinpoint process problems. Real-time monitoring of ion implantation. GILBERTA. GRUBER and NORMA B. RILEY. Semiconductor int., 178 (May 1988). Optical dosimetry monitoring is routinely performed by lab operators to control implantation processes. Low-frequency noise in GaAs layers grown by molecular beam epitaxy. MUNECAZU TACANO, YOSHINOBU SUGIYAMA, TAKASHI TAGUCHI and HAJ1ME SOGA. Solid-St. Electron. 31, 1215 (1988). Low-frequency noise in n-GaAs layers grown by molecular beam epitaxy has been systematically studied for various carrier concentrations and device dimensions. The noise decreases linearly with an increase in total carriers and layer thickness. The frequency dependence of the noise varies at a rate of f - 1.5 in the devices with SnAu contacts, and at the rates of f - 1 2 to f 2.o in those with AuGe contacts. SnAu ohmic contacts have noise levels 20dB lower than those of AuGe contacts. Surface cap layers either doped to nor p-type have little effect on the overall frequency dependence of the noise. Laser-based pattern generation. P1ETER BURGGRAAF. Semiconductor int., 116 (May 1988). Lasers are being used in a variety of pattern generations systems for both mask making and direct write applications. Particle control in high-current ion implanters. WES WEISENBERGER. Semiconductor int., 188 (May 1988). Particle flux monitor installed in a high-current ion implanter provides real time particle measurement during production runs and cleaning cycles. The effect of nitrogen implantation on the tribological properties of gold-based alloys and electroplated palladium.
scope and energy-dispersive microprobe analyses revealed the existence of a RuO2-poor area in the resistor adjacent to the copper terminals. The resistivity in this area is higher than that in areas removed from the terminals, and it increased with the retiring temperature. These facts indicated that the resistance change is caused mainly by the diffusion of Ru to the copper conductor. Various approaches were taken to minimize this phenomenon. The most effective was insertion of a conductor pad between the copper conductor and resistor. Resistors with this type of A g - P d conductor pad meet the various requirements for practical application of hybrid ICs. Based on these results, a prototype, highfrequency hybrid IC (voltage-controlled oscillator, VCO) was fabricated.
BEAM
TECHNIQUES
PATRICK W. LEECH. IEEE Trans. Compon. Hybrids m f9 Technol. l l , 16 (1988). The effect of nitrogen ion implantation on the friction and wear behavior of Au26Ag3Ni, Au3oPdzg.sAgl ~Sn, and AusAg alloys and electroplated palladium has been investigated. Rider-on-flat experiments were conducted using nitrogen-implanted (dosage of 2 × 1017 ions-cm 2) and unimplanted specimens in order to make detailed comparison of the characteristics in reciprocating sliding. N~- implantation of either the rider (AuaAg) or the flat (Auz6Ag3Ni, Au30Pd29 5Agl.sSn) produced a significant reduction in coefficient of friction and in the extent of surface wear sustained during sliding. Layers of electroplated palladium showed only minor change in friction and in sliding damage to the flat following N + implantation of both specimen surfaces.
Discrete wire bonding using laser energy. P. CHALCO,A. GUPTA, B. HUSSE¥, R. HODGSON and G. ARJAVALINGAM. Semiconductor int., 130 (May 1988). A wire bonding process for discrete wires using laser energy has been demonstrated on thin gold/nickel alloy pad surface metallurgies. New microwave ion source for multiply charged ion beam production. K. TOKIGUCHI,K. AMEM1YA,H. KOIKE,N. SAKUDO and T. SEKI. Vacuum 38, 487 (1988). To obtain high-current beams of rather lower-charge-state multiply charged ions, a new microwave ion source is designed. Ion beams of a few mA are extracted from the plasma and mass-analysed. The extracted beams have large quantities of multiply charged Ar ions at relatively lower gas pressures of 10 4-10-3 Pa. In addition, these quantities tend to effectively increase with microwave power. The microwave power necessary for mAclass implantation current of low-charge-state ions is estimated to be from 3 5 kW. Rapid thermal annealing effects on gate oxide of ion implanted devices. F. HASHEM1 and C. A. PAZ DE ARAUJO. Semiconductor int., 152 (May 1988). Rapid thermal annealing of gate oxides doped with boron is compared to furnace annealing by examining device electrical parameters.
World Abstracts on Microelectronics and Reliability
A comparison between noise measurements and conventional electromigratiou reliability testing. J. G. COYrLE, T. M. CriEs and K. P. RODBELL. Proc. IEEE/IRPS, 203 (1988). The observed sensitivity of noise measurements to electromigration damage in metal films suggests that they be used as a non-destructive test for measuring thin film interconnect reliability. This paper reports the results of experiments designed to compare conventional median-time-to-failure (MTF) data with those obtained through the use of noise measurements. Comparisons are made on aluminum and aluminum-copper alloy films from identical wafers fabricated with varying electromigration-sensitive parameters. Application of copper conductor and ruthenium containing oxides-glass resistor to high-frequency hybrid ICs for a portable cellular radio. TOSHIO OGAWA. MITURU FUJII, TADAMICHI ASA1, AKIRA IKEGAMI and TAKAE KOBAYASHI. IEEE Trans. Compon. Hybrids m)~7 Technol. 11, 211 (1988). Interest in thick-film copper hybrid ICs with resistors for high frequency use has increased considerably during the past few years. Technical uncertainties are being resolved and the potential advantages of the copper-conductor thickfilm system are being recognized. This paper presents an assessment of a copper-conductor and resistor system and its performance in a high-frequency hybrid application. Resistance of the copper-compatible resistor, containing RuO2, increases after retiring over 600°C and drastically increases as the firing temperature is raised. The cause of this resistance change was examined. Scanning-electron micro-
9. E L E C T R O N ,
ION
AND
Ultra-low dielectric constant porous silica thick films for high-speed IC packaging. UMAR MOHIDEEN,T. R. GURURAJA, LESLIE E. CROSS and RUSTUM RoY. IEEE Trans. Compon. Hybrids mr9 Technol. II, 159 (1988). Interconnect systems which are required in high-speed GaAs digital ICs use stripline techniques for signal traces which must be deposited over very low dielectric constant substrates. Materials with relative dielectric constant k less than 3 and having low-loss tangents up to microwave frequencies are required for ceramic materials. Such values are impossible to achieve in single-phase ceramic monoliths and composite approaches are necessary. A technique for preparing porous silica films of thickness 1 to 10 ~m is presented. The dielectric constants of these films are in the range of 2.4 to 2.8 with a loss tangent less than 0.005 at l kHz.
LASER
Troubleshooting ion implantation processes. CHARLES B. YARLING and W. ANDREW KEENAN. Semiconductor int., 164 (May 1988). A reliable and accurate approach to testing and process control allows process engineers to quickly pinpoint process problems. Real-time monitoring of ion implantation. GILBERTA. GRUBER and NORMA B. RILEY. Semiconductor int., 178 (May 1988). Optical dosimetry monitoring is routinely performed by lab operators to control implantation processes. Low-frequency noise in GaAs layers grown by molecular beam epitaxy. MUNECAZU TACANO, YOSHINOBU SUGIYAMA, TAKASHI TAGUCHI and HAJ1ME SOGA. Solid-St. Electron. 31, 1215 (1988). Low-frequency noise in n-GaAs layers grown by molecular beam epitaxy has been systematically studied for various carrier concentrations and device dimensions. The noise decreases linearly with an increase in total carriers and layer thickness. The frequency dependence of the noise varies at a rate of f - 1.5 in the devices with SnAu contacts, and at the rates of f - 1 2 to f 2.o in those with AuGe contacts. SnAu ohmic contacts have noise levels 20dB lower than those of AuGe contacts. Surface cap layers either doped to nor p-type have little effect on the overall frequency dependence of the noise. Laser-based pattern generation. P1ETER BURGGRAAF. Semiconductor int., 116 (May 1988). Lasers are being used in a variety of pattern generations systems for both mask making and direct write applications. Particle control in high-current ion implanters. WES WEISENBERGER. Semiconductor int., 188 (May 1988). Particle flux monitor installed in a high-current ion implanter provides real time particle measurement during production runs and cleaning cycles. The effect of nitrogen implantation on the tribological properties of gold-based alloys and electroplated palladium.
scope and energy-dispersive microprobe analyses revealed the existence of a RuO2-poor area in the resistor adjacent to the copper terminals. The resistivity in this area is higher than that in areas removed from the terminals, and it increased with the retiring temperature. These facts indicated that the resistance change is caused mainly by the diffusion of Ru to the copper conductor. Various approaches were taken to minimize this phenomenon. The most effective was insertion of a conductor pad between the copper conductor and resistor. Resistors with this type of A g - P d conductor pad meet the various requirements for practical application of hybrid ICs. Based on these results, a prototype, highfrequency hybrid IC (voltage-controlled oscillator, VCO) was fabricated.
BEAM
TECHNIQUES
PATRICK W. LEECH. IEEE Trans. Compon. Hybrids m f9 Technol. l l , 16 (1988). The effect of nitrogen ion implantation on the friction and wear behavior of Au26Ag3Ni, Au3oPdzg.sAgl ~Sn, and AusAg alloys and electroplated palladium has been investigated. Rider-on-flat experiments were conducted using nitrogen-implanted (dosage of 2 × 1017 ions-cm 2) and unimplanted specimens in order to make detailed comparison of the characteristics in reciprocating sliding. N~- implantation of either the rider (AuaAg) or the flat (Auz6Ag3Ni, Au30Pd29 5Agl.sSn) produced a significant reduction in coefficient of friction and in the extent of surface wear sustained during sliding. Layers of electroplated palladium showed only minor change in friction and in sliding damage to the flat following N + implantation of both specimen surfaces.
Discrete wire bonding using laser energy. P. CHALCO,A. GUPTA, B. HUSSE¥, R. HODGSON and G. ARJAVALINGAM. Semiconductor int., 130 (May 1988). A wire bonding process for discrete wires using laser energy has been demonstrated on thin gold/nickel alloy pad surface metallurgies. New microwave ion source for multiply charged ion beam production. K. TOKIGUCHI,K. AMEM1YA,H. KOIKE,N. SAKUDO and T. SEKI. Vacuum 38, 487 (1988). To obtain high-current beams of rather lower-charge-state multiply charged ions, a new microwave ion source is designed. Ion beams of a few mA are extracted from the plasma and mass-analysed. The extracted beams have large quantities of multiply charged Ar ions at relatively lower gas pressures of 10 4-10-3 Pa. In addition, these quantities tend to effectively increase with microwave power. The microwave power necessary for mAclass implantation current of low-charge-state ions is estimated to be from 3 5 kW. Rapid thermal annealing effects on gate oxide of ion implanted devices. F. HASHEM1 and C. A. PAZ DE ARAUJO. Semiconductor int., 152 (May 1988). Rapid thermal annealing of gate oxides doped with boron is compared to furnace annealing by examining device electrical parameters.