Reactive sputtering method

Abstract

In a reactive sputtering apparatus, an inert-gas supplying hole is provided in a movable target unit whose one end is open and whose conductance is controlled, and a reactive gas containing at least fluorine or oxygen can be supplied to a space between the target and a substrate. The apparatus is constructed so as to emit the reactive gas toward the substrate. A reactive-gas emitting location is in the space between the target and the substrate such that a concentration of the reactive gas on the substrate surface can be maintained at a higher level. When the target is moved, a reactive-gas emitting port is moved or the reactive-gas emitting location is changed. The concentration of the reactive gas on the substrate surface can be effectively kept constant, and a high-quality optical thin film can be formed.

1 . A reactive sputtering method comprising the steps of:
 disposing in an apparatus a hollow target with an opening portion provided at least at one end thereof and a supplying hole for admitting an inert gas into the interior thereof, and a substrate; and   performing sputtering by admitting an inert gas into the target through the supplying hole while spraying a reactive gas toward a surface of the substrate from a position between the supplying hole and the substrate.   
   
   
       2 . A reactive sputtering method according to  claim 1 , wherein the sputtering is performed such that no inverse diffusion of the reactive gas occurs. 
   
   
       3 . A reactive sputtering method according to  claim 1 , wherein the sputtering is performed by controlling a partial pressure of the reactive gas on a surface of the target. 
   
   
       4 . A reactive sputtering method according to  claim 3 , wherein the partial pressure of the reactive gas is controlled while a surface condition of the target is observed. 
   
   
       5 . A reactive sputtering method according to  claim 1 , wherein a conductance between the target and the substrate is made equal to or less than 5 m 3 /s. 
   
   
       6 . A reactive sputtering method according to  claim 1 , wherein an emitting port of a conduit for supplying the reactive gas is disposed in a space between the target and the substrate. 
   
   
       7 . A reactive sputtering method according to  claim 1 , wherein the sputtering is performed while the target is moved. 
   
   
       8 . A reactive sputtering method according to  claim 7 , wherein an emitting port of the reactive gas is also moved together with the movement of the target, and the sputtering is performed while a relative positional relation between the target and the reactive-gas admitting port is maintained constant at all times. 
   
   
       9 . (canceled) 
   
   
       10 . A reactive sputtering method according to  claim 1 , wherein the reactive gas is a gas containing fluorine. 
   
   
       11 . A reactive sputtering method according to  claim 10 , wherein the gas containing fluorine includes at least one of F 2 , NF 3  and CF 4 . 
   
   
       12 . A reactive sputtering method according to  claim 1 , wherein the reactive gas is a gas containing oxygen. 
   
   
       13 . A reactive sputtering method according to  claim 12 , wherein the gas containing oxygen contains at least one of 0 2  and water vapor. 
   
   
       14 . A reactive sputtering method according to  claim 1 , wherein a conductance of an emitting port for the reactive gas is made equal to or less than 1×10 −4  m 3 /s. 
   
   
       15 . A reactive sputtering method according to  claim 1 , wherein an emitting speed of the reactive gas is made equal to or more than 50 m/s. 
   
   
       16 .- 19 . (canceled) 
   
   
       20 . A reactive sputtering apparatus comprising:
 a vacuum chamber;   a unit for holding in the vacuum chamber a cylindrical target with an opening portion provided at least at one end thereof and a supplying hole for admitting an inert gas into an interior thereof;   a unit for mounting a substrate;   a unit for admitting an inert gas into the target through the supplying hole; and   a unit for supplying a reactive gas while spraying the reactive gas toward a surface of the substrate from a position disposed between the supplying hole and the substrate.   
   
   
       21 . A reactive sputtering apparatus according to  claim 20 , wherein a conductance between the target and the substrate is controlled to be equal to or less than a predetermined value. 
   
   
       22 . A reactive sputtering apparatus according to  claim 21 , wherein the conductance between the target and the substrate is made equal to or less than 5 m 3 /s. 
   
   
       23 . A reactive sputtering apparatus according to  claim 20 , wherein an emitting port for supplying the reactive gas is disposed in a space between the supplying hole and the substrate. 
   
   
       24 . A reactive sputtering apparatus according to  claim 20 , wherein the target is movable. 
   
   
       25 . A reactive sputtering apparatus according to  claim 24 , wherein an emitting port of the reactive gas is also movable together with the movement of the target, and a relative positional relation between the target and the reactive-gas admitting port is maintained constant at all times. 
   
   
       26 . (canceled) 
   
   
       27 . A reactive sputtering apparatus according to  claim 20 , wherein the reactive gas is a gas containing fluorine. 
   
   
       28 . A reactive sputtering apparatus according to  claim 27 , wherein the gas containing fluorine includes at least one of F 2 , NF 3 , and CF 4 . 
   
   
       29 . A reactive sputtering apparatus according to  claim 20 , wherein the reactive gas is a gas containing oxygen. 
   
   
       30 . A reactive sputtering apparatus according to  claim 20 , wherein the gas containing oxygen contains at least one of 0 2  and water vapor. 
   
   
       31 . A reactive sputtering apparatus according to  claim 20 , wherein a conductance of an emitting port for the reactive gas is made equal to or less than 1×10 −4  m 3 /s. 
   
   
       32 . A reactive sputtering apparatus according to  claim 20 , wherein an emitting speed of the reactive gas is made equal to or more than 50 m/s.