Coating apparatus – Control means responsive to a randomly occurring sensed... – Responsive to condition of coating material
Reexamination Certificate
1998-09-16
2001-01-16
Mills, Gregory (Department: 1763)
Coating apparatus
Control means responsive to a randomly occurring sensed...
Responsive to condition of coating material
C118S726000, C118S728000, C156S345420
Reexamination Certificate
active
06174371
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to substrate treating methods and apparatus for use in modifying films formed on substrates such as semiconductor wafers. More particularly, the invention relates to a technique of heating substrates in an atmosphere including the vapor of a treating liquid or solution.
2. Description of the Related Art
An outline of a conventional substrate treating apparatus of this type will be described with reference to FIG.
1
.
This substrate treating apparatus includes a vaporizer
10
for vaporizing a treating liquid, and a treating chamber
20
for treating substrate or wafer W in the vapor of the treating liquid supplied from the vaporizer
10
.
The vaporizer
10
has a bubbling tank
11
for storing the treating liquid which is heated by a heater
12
provided for the bubbling tank
11
. A gas feed pipe
13
extends into the bubbling tank
11
for mixing a carrier gas such as nitrogen gas into the treating liquid. A vapor transmitting pipe
14
extends from an upper position of the bubbling tank
11
. The vapor of the treating liquid generated by heating is transmitted along with the carrier gas through the vapor transmitting pipe
14
to the treating chamber
20
.
The treating chamber
20
includes a substrate support table
21
for supporting a substrate such as a semiconductor wafer W under treatment, and an open/close main body
22
disposed over the support table
21
. The support table
21
has a heater
23
embedded therein for heating the wafer W, and a lift mechanism
24
for raising and lowering the wafer W. The lift mechanism
24
includes a plurality of support pins
25
for supporting the wafer W, and an air cylinder
26
for raising and lowering the support pins
25
. The vapor transmitting pipe
14
is connected to an upper position of the main body
22
to introduce the vapor of the treating liquid into a treating space
27
defined by the main body
24
.
The conventional substrate treating apparatus noted above is operable for treatment of wafer W as follows.
With the main body
22
retracted upward to open the treating space
27
, the wafer W is brought in and placed on the support pins
25
projecting from the support table
21
. Subsequently, the main body
22
is lowered to close the treating space
27
tight. As the vapor of the treating liquid is introduced from the vaporizer
10
into the treating space
27
, the support pins
25
are lowered to place the wafer W on the support table
21
. The wafer W is treated in a vaporous atmosphere of the treating liquid while being heated by the support table
21
.
The above conventional substrate treating apparatus has the following drawback.
When the vapor of the treating liquid is introduced into the treating space
27
, the wafer W is in a position away from the support table
21
, and is therefore below a heating temperature set to the support table
21
. As a result, the temperature of the wafer W is lower than the temperature of the vapor of the treating liquid introduced into the treating space
27
. The vapor of the treating liquid introduced into the treating space
27
is cooled adjacent the wafer W and condenses on the wafer W. The condensation degrades the film formed on the surface of wafer W under treatment.
To overcome such an inconvenience, the wafer W may be placed and heated on the support table
21
prior to introduction into the treating space
27
of the vapor of the treating liquid. In the case of treatment conducted in such a sequence, the film formed on the wafer W would temporarily be heated in an atmosphere not including the vapor of the treating liquid. Certain types of film require treatment in the vapor of the treating liquid in order to avoid dispersion of components contained in the film. The treatment conducted in the above sequence would disperse the components from the film, resulting in a different problem of deteriorating the film.
SUMMARY OF THE INVENTION
The present invention has been made having regard to the state of the art noted above, and its object is to provide a substrate treating method and apparatus for heating a substrate in a stable atmosphere including the vapor of a treating liquid or solution, without allowing the vapor to condense on the substrate.
The above object is fulfilled, according to a first aspect of the present invention, by a substrate treating method for heating a substrate in an atmosphere including vapor of a treating liquid, comprising a treating vapor mixture generating step for generating a treating vapor mixture by mixing the vapor of the treating liquid with a diluting gas; a partial pressure ratio adjusting step for varying a mixing quantity of at least one of the vapor of the treating liquid and the diluting gas in the treating vapor mixture generating step, so that a partial pressure ratio of the vapor of the treating liquid in the treating vapor mixture increases with time; a treating vapor mixture transmitting step for transmitting the treating vapor mixture to a treating chamber having a substrate support table heated to a predetermined temperature and for supporting the substrate; a substrate lowering step for lowering the substrate in the treating chamber from a separate position away from the substrate support table to a resting position on the substrate support table; and a downward displacement controlling step for controlling downward displacements of the substrate in the substrate lowering step, according to variations in the partial pressure ratio of the vapor of the treating liquid in the treating vapor mixture, to maintain a substantially fixed ratio between a vapor pressure and a saturation pressure of the vapor of the treating liquid in the treating vapor mixture adjacent a surface of the substrate under treatment.
The invention provides also an apparatus according to the first aspect, which employs the method according to the first aspect.
That is, a substrate treating apparatus for heating a substrate in an atmosphere including vapor of a treating liquid, according to the first aspect of the invention, comprises a treating vapor mixture generating unit for generating a treating vapor mixture by mixing the vapor of the treating liquid with a diluting gas; a treating chamber for receiving the treating vapor mixture; a substrate support table disposed in the treating chamber, heated to a predetermined temperature and for supporting the substrate; a substrate lift mechanism for raising and lowering the substrate between a separate position away from the substrate support table and a resting position on the substrate support table; a partial pressure ratio adjusting device for varying a mixing quantity of at least one of the vapor of the treating liquid and the diluting gas, so that a partial pressure ratio of the vapor of the treating liquid in the treating vapor mixture generated by the treating vapor mixture generating unit increases with time; and a drive control device for controlling downward displacements of the substrate lowered by the substrate lift mechanism from the separate position to the resting position in the treating chamber, according to variations in the partial pressure ratio of the vapor of the treating liquid in the treating vapor mixture, to maintain a substantially fixed ratio between a vapor pressure and a saturation pressure of the vapor of the treating liquid in the treating vapor mixture adjacent a surface of the substrate under treatment.
The functions and advantages of the above apparatus in the first aspect of the invention will be described hereinafter. The functions and advantages of the method in the first aspect of the invention will be apparent from those of the apparatus, and will not be described to avoid repetition.
A substrate loaded into the treating chamber is first placed by the substrate lift mechanism in the separate position away from the substrate support table. Subsequently, the treating vapor mixture generated by mixing the vapor of the treating liquid with the diluting gas at the treating vapor mixt
Iseki Izuru
Yamashita Tetsuro
Dainippon Screen Mfg. Co,. Ltd.
Hassanzadeh Parviz
Mills Gregory
Ostrolenk Faber Gerb & Soffen, LLP
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