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Vapor deposited tungsten for silicon devices
WORLD
ABSTRACTS
ON
MICROELECTRONICS
t h e o p t i m u m e q u i p m e n t for each practical r e q u i r e m e n t . A n analysis of t h e m o r e c o m m o n l y u s e d deposition s y s t e m s s h o w s t h a t t h e m o s t efficient s y s t e m contains three substrate holders with planetary motion with respect to t h e evaporator.
AND
RELIABILITY
331
indicate t h e superiority of t u n g s t e n over a l u m i n u m in t h e s e areas. A d v a n t a g e s of t u n g s t e n for multilevel metallization are p o i n t e d out.
*Thermal treatment of Cr-Si0 cermet thin films. (Thin Film Conf., C a n n e s 1970.) J. GASPERIC a n d B.
Plasma diagnostics of sputtering glow discharges. J. W. COBURN,E. KAY. Solid State Technol., D e c e m b e r (1971), p. 49. I n an effort to provide i n f o r m a t i o n a b o u t t h e processes in a s p u t t e r i n g glow discharge w h i c h influence t h e properties of a s p u t t e r e d film, a bakeable u l t r a h i g h v a c u u m s y s t e m h a s b e e n c o n s t r u c t e d in w h i c h we can m e a s u r e t h e m a s s a n d energy of particles i n c i d e n t o n t h e s u b s t r a t e s of a p l a n a r diode s p u t t e r i n g s y s t e m . T h e operation of this s y s t e m is described a n d s o m e observations of t h e positive ions striking t h e s u b s t r a t e s are p r e s e n t e d . It is s h o w n t h a t t h e d o m i n a n t ionization process for s p u t t e r e d species is t h e P e n n i n g process and, as a result, t h e positive ions can serve as a reliable a n d very sensitive indicator of t h e total particle
flux.
NAVINSEK. I n s t i t u t Jozef Stefan, Ljubljana, Yugoslavis. S e p t e m b e r (1970) pp. 11. (T72-00365 I J S - R - 5 8 7 ) (1134-7202). F l a s h evaporated C r - S i 0 c e r m e t t h i n films have b e e n systematically investigated in t h e t e m p e r a t u r e range f r o m 20 ° to 600°C. C o m p o s i t i o n s of 80/20 a n d 50/50 (by percentage weight) were used. T h e effects of stabilization, ageing, surface r o u g h n e s s a n d residual gases on electrical properties for different conditions of preparations are studied. T h e following properties of evaporated c e r m e t films are investigated: thickness a n d m a s s , chemical composition, resistivities a n d t e m p e r a t u r e coefficients of resistance ( T C R ) u s i n g t h e T o k a n s k y a n d m i c r o g r a v i m e t r i c m e t h o d , t h e q u a r t z microbalance m e t h o d , X - r a y fluorescence a n d m i c r o p r o b e analysis, electrical m e a s u r e m e n t s , a n d t h e influence of residual gases.
Film technology in m i c r o w a v e integrated circuits. M . CAULTON. Proc. 1EEE 59, No. 10 (1971), p. 1481. A review of t h e material t e c h n o l o g y for m i c r o w a v e integrated circuits ( M I C s ) is presented. T h e types of m i c r o w a v e circuit m e d i a that have b e e n u s e d are described a n d classified as a f u n c t i o n of t h e a m o u n t of size r e d u c t i o n or integration w h i c h c o r r e s p o n d s to t h e effective dielectric c o n s t a n t of t h e media. T h e materials u s e d for substrates, conductors, dielectrics, a n d resistors are considered in t e r m s of t h e r e q m r e m e n t s for m i c r o wave circuits. T h e fabrication of m u h i l a y e r e d t h i n - f i l m circuits a n d t h e various t h i n - f i l m c o m b i n a t i o n s that h a v e b e e n u s e d in M I C s are discussed. T h e various loss c o n t r i b u t i o n s for microstrip circuits p r o d u c e d by t h i n a n d thick-film t e c h n o l o g y a n d s u b s t r a t e material are c o m p a r e d w i t h each o t h e r as a f u n c t i o n of frequency. It is c o n c l u d e d t h a t m i c r o w a v e circuits operating at frequencies 2 G H z a n d above require thin-films on p u r e s m o o t h substrates.
*Sputtered z i n c sulphide films on silicon. T. G. R. RAWLINS. Signals Res. ~q Dev. Est., C h r i s t c h u r c h , H a n t s . (1093-7203) T 7 2 - 0 0 6 8 4 M S R D E - R E P - 7 1 0 0 6 , M a r c h (1971), pp. 14. T h e design of a triode R F s p u t t e r i n g s y s t e m for t h e deposit of h i g h p u r i t y films of Z i n c S u l p h i d e is outlined. It is s h o w n t h a t t h e deposited films have a h i g h degree of purity a n d are h i g h l y oriented crystallographically.
Problems associated with printing of "thick film" circuits. B. M . AUSTIN. Proc. Tech. Prog. I N T E R N E P C O N '71, Brighton. 19-21 O c t o b e r (1971), p. 269. Starting in 1964, t h e electronic i n d u s t r y awoke to a n e w c i r c u i t - m a k i n g technology " t h i c k - f i l m " , to p r o d u c e p r o d u c t s m o r e compatible to m i n i a t u r e t h i n film c o m p o nents. Since t h e screen p r i n t e r was t h e " h e a r t " of this n e w concept, m o r e was i m m e d i a t e l y asked of it t h a n ever before, s u c h as 0"005 in. wide lines or less; processing of t h i n s u b s t r a t e s that w a v e d a n d curled; p r i n t s that n e e d thickness control w i t h i n 0'0001 in. at m o s t ; p r i n t thicknesses u p to 0"001 in. or better after firing; fine definition of lines 1 in. long or longer; p r i n t i n g w i t h inks t h a t were like p e a n u t b u t t e r ; a n d edge f o r m a t i o n of p r i n t s that look a l m o s t architectural . . . to m e n t i o n a few.
Investigation of tantalum film properties by layers. F. C. LIVERMORE et al. J. Vac. Sci. Technol. 8, No. 1, J a n u a r y - F e b r u a r y (1971), p. 155. A t e c h n i q u e has b e e n developed w h i c h has m a d e it possible to d e t e r m i n e t h e resistivity a n d t h e t e m p e r a t u r e coefficient of resistance ( T C R ) of layers at different d e p t h s in t h i n t a n t a l u m films. T h e m e t h o d involves a m e a s u r e m e n t of t h e sheet resistance a n d T C R before a n d after anodization steps, a n d s i m u l t a n e o u s m e a s u r e m e n t s of t h e oxide g r o w t h kinetics. It is s h o w n that there can be a significant variation in t h e film properties with depth.
Vapor deposited tungsten for silicon devices. J. M. SHAW a n d J. A. AMICK, Solid State Technol., D e c e m b e r (1971), p. 53. T h e u s e of t u n g s t e n for t h e metallization of silicon devices a n d integrated circuits is investigated. T h e t e c h n o l o g y of d e p o s i t i n g t h i n t u n g s t e n films is described, u s i n g t u n g s t e n hexa-fluoride as t h e t u n g s t e n source. Physical a n d electrical properties of t h e film are presented, i n c l u d i n g s u c h characteristics as resistivity, h a r d n e s s , a d h e r e n c e a n d t h e effect on device parameters. S t e p - s t r e s s life tests a n d h i g h t e m p e r a t u r e storage tests
Electrical characteristics of double electrode r.f. sputtering systems. 1. The discharge. G. N. JACKSON. Vacuum 21, No. 11, p. 533. T h e parallel c o n d u c t a n c e a n d capacitance of t h e r.f. discharge in a disc a n d a n n u l u s double electrode r.f. s p u t t e r i n g s y s t e m operating at 7"1 M H z have b e e n m e a s u r e d . Various s p u t t e r i n g conditions were u s e d i n c l u d i n g r.f. p o w e r levels of 1-15 k W . m -2, p r e s s u r e s f r o m 3 to 10 m torr of argon, target to work table separations f r o m 35 to 70 m m
ABSTRACTS
ON
MICROELECTRONICS
t h e o p t i m u m e q u i p m e n t for each practical r e q u i r e m e n t . A n analysis of t h e m o r e c o m m o n l y u s e d deposition s y s t e m s s h o w s t h a t t h e m o s t efficient s y s t e m contains three substrate holders with planetary motion with respect to t h e evaporator.
AND
RELIABILITY
331
indicate t h e superiority of t u n g s t e n over a l u m i n u m in t h e s e areas. A d v a n t a g e s of t u n g s t e n for multilevel metallization are p o i n t e d out.
*Thermal treatment of Cr-Si0 cermet thin films. (Thin Film Conf., C a n n e s 1970.) J. GASPERIC a n d B.
Plasma diagnostics of sputtering glow discharges. J. W. COBURN,E. KAY. Solid State Technol., D e c e m b e r (1971), p. 49. I n an effort to provide i n f o r m a t i o n a b o u t t h e processes in a s p u t t e r i n g glow discharge w h i c h influence t h e properties of a s p u t t e r e d film, a bakeable u l t r a h i g h v a c u u m s y s t e m h a s b e e n c o n s t r u c t e d in w h i c h we can m e a s u r e t h e m a s s a n d energy of particles i n c i d e n t o n t h e s u b s t r a t e s of a p l a n a r diode s p u t t e r i n g s y s t e m . T h e operation of this s y s t e m is described a n d s o m e observations of t h e positive ions striking t h e s u b s t r a t e s are p r e s e n t e d . It is s h o w n t h a t t h e d o m i n a n t ionization process for s p u t t e r e d species is t h e P e n n i n g process and, as a result, t h e positive ions can serve as a reliable a n d very sensitive indicator of t h e total particle
flux.
NAVINSEK. I n s t i t u t Jozef Stefan, Ljubljana, Yugoslavis. S e p t e m b e r (1970) pp. 11. (T72-00365 I J S - R - 5 8 7 ) (1134-7202). F l a s h evaporated C r - S i 0 c e r m e t t h i n films have b e e n systematically investigated in t h e t e m p e r a t u r e range f r o m 20 ° to 600°C. C o m p o s i t i o n s of 80/20 a n d 50/50 (by percentage weight) were used. T h e effects of stabilization, ageing, surface r o u g h n e s s a n d residual gases on electrical properties for different conditions of preparations are studied. T h e following properties of evaporated c e r m e t films are investigated: thickness a n d m a s s , chemical composition, resistivities a n d t e m p e r a t u r e coefficients of resistance ( T C R ) u s i n g t h e T o k a n s k y a n d m i c r o g r a v i m e t r i c m e t h o d , t h e q u a r t z microbalance m e t h o d , X - r a y fluorescence a n d m i c r o p r o b e analysis, electrical m e a s u r e m e n t s , a n d t h e influence of residual gases.
Film technology in m i c r o w a v e integrated circuits. M . CAULTON. Proc. 1EEE 59, No. 10 (1971), p. 1481. A review of t h e material t e c h n o l o g y for m i c r o w a v e integrated circuits ( M I C s ) is presented. T h e types of m i c r o w a v e circuit m e d i a that have b e e n u s e d are described a n d classified as a f u n c t i o n of t h e a m o u n t of size r e d u c t i o n or integration w h i c h c o r r e s p o n d s to t h e effective dielectric c o n s t a n t of t h e media. T h e materials u s e d for substrates, conductors, dielectrics, a n d resistors are considered in t e r m s of t h e r e q m r e m e n t s for m i c r o wave circuits. T h e fabrication of m u h i l a y e r e d t h i n - f i l m circuits a n d t h e various t h i n - f i l m c o m b i n a t i o n s that h a v e b e e n u s e d in M I C s are discussed. T h e various loss c o n t r i b u t i o n s for microstrip circuits p r o d u c e d by t h i n a n d thick-film t e c h n o l o g y a n d s u b s t r a t e material are c o m p a r e d w i t h each o t h e r as a f u n c t i o n of frequency. It is c o n c l u d e d t h a t m i c r o w a v e circuits operating at frequencies 2 G H z a n d above require thin-films on p u r e s m o o t h substrates.
*Sputtered z i n c sulphide films on silicon. T. G. R. RAWLINS. Signals Res. ~q Dev. Est., C h r i s t c h u r c h , H a n t s . (1093-7203) T 7 2 - 0 0 6 8 4 M S R D E - R E P - 7 1 0 0 6 , M a r c h (1971), pp. 14. T h e design of a triode R F s p u t t e r i n g s y s t e m for t h e deposit of h i g h p u r i t y films of Z i n c S u l p h i d e is outlined. It is s h o w n t h a t t h e deposited films have a h i g h degree of purity a n d are h i g h l y oriented crystallographically.
Problems associated with printing of "thick film" circuits. B. M . AUSTIN. Proc. Tech. Prog. I N T E R N E P C O N '71, Brighton. 19-21 O c t o b e r (1971), p. 269. Starting in 1964, t h e electronic i n d u s t r y awoke to a n e w c i r c u i t - m a k i n g technology " t h i c k - f i l m " , to p r o d u c e p r o d u c t s m o r e compatible to m i n i a t u r e t h i n film c o m p o nents. Since t h e screen p r i n t e r was t h e " h e a r t " of this n e w concept, m o r e was i m m e d i a t e l y asked of it t h a n ever before, s u c h as 0"005 in. wide lines or less; processing of t h i n s u b s t r a t e s that w a v e d a n d curled; p r i n t s that n e e d thickness control w i t h i n 0'0001 in. at m o s t ; p r i n t thicknesses u p to 0"001 in. or better after firing; fine definition of lines 1 in. long or longer; p r i n t i n g w i t h inks t h a t were like p e a n u t b u t t e r ; a n d edge f o r m a t i o n of p r i n t s that look a l m o s t architectural . . . to m e n t i o n a few.
Investigation of tantalum film properties by layers. F. C. LIVERMORE et al. J. Vac. Sci. Technol. 8, No. 1, J a n u a r y - F e b r u a r y (1971), p. 155. A t e c h n i q u e has b e e n developed w h i c h has m a d e it possible to d e t e r m i n e t h e resistivity a n d t h e t e m p e r a t u r e coefficient of resistance ( T C R ) of layers at different d e p t h s in t h i n t a n t a l u m films. T h e m e t h o d involves a m e a s u r e m e n t of t h e sheet resistance a n d T C R before a n d after anodization steps, a n d s i m u l t a n e o u s m e a s u r e m e n t s of t h e oxide g r o w t h kinetics. It is s h o w n that there can be a significant variation in t h e film properties with depth.
Vapor deposited tungsten for silicon devices. J. M. SHAW a n d J. A. AMICK, Solid State Technol., D e c e m b e r (1971), p. 53. T h e u s e of t u n g s t e n for t h e metallization of silicon devices a n d integrated circuits is investigated. T h e t e c h n o l o g y of d e p o s i t i n g t h i n t u n g s t e n films is described, u s i n g t u n g s t e n hexa-fluoride as t h e t u n g s t e n source. Physical a n d electrical properties of t h e film are presented, i n c l u d i n g s u c h characteristics as resistivity, h a r d n e s s , a d h e r e n c e a n d t h e effect on device parameters. S t e p - s t r e s s life tests a n d h i g h t e m p e r a t u r e storage tests
Electrical characteristics of double electrode r.f. sputtering systems. 1. The discharge. G. N. JACKSON. Vacuum 21, No. 11, p. 533. T h e parallel c o n d u c t a n c e a n d capacitance of t h e r.f. discharge in a disc a n d a n n u l u s double electrode r.f. s p u t t e r i n g s y s t e m operating at 7"1 M H z have b e e n m e a s u r e d . Various s p u t t e r i n g conditions were u s e d i n c l u d i n g r.f. p o w e r levels of 1-15 k W . m -2, p r e s s u r e s f r o m 3 to 10 m torr of argon, target to work table separations f r o m 35 to 70 m m