Method and apparatus for treating a substrate

A plane of a treatment liquid holder having a number of through holes faces a treatment surface of a substrate. A treatment liquid is held between the treatment surface and the liquid holder by utilizing a surface tension of the treatment liquid. Since the treatment liquid is applied only to the treatment surface, an extremely small amount of treatment liquid suffices for the treatment. In addition, since a fresh treatment liquid can be used in every treatment, cross-contamination is suppressed and the treatment can be performed with safety at a low cost.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method of treating a semiconductor 
substrate with fluid (especially with liquid) and an apparatus for the 
same and, more particularly, to a method of treating only one surface of a 
flat substrate for use in a semiconductor device or a liquid crystal 
display device and an apparatus for the same. 
2. Description of the Related Art 
As steps of treating a semiconductor substrate (silicon wafer) with 
chemicals, there are various steps such as photoresist applying, etching, 
cleaning, photoresist removing, developing, plating, etc. A conventional 
steps of treating a silicon wafer with chemicals will be described in 
detail. 
FIG. 1 is a crosssectional view of a treatment apparatus wherein a silicon 
wafer is immersed in a treatment tub 11 to be treated. In case of wafer 
cleaning or resist removing, a treatment liquid 12 is composed of H.sub.2 
SO.sub.4 and H.sub.2 O.sub.2 mixed in a ratio of 10:1, for example, and is 
filled in a treatment tub 11 by a total amount of 25 l. The treatment tub 
11 is made of quartz or the like. The treatment liquid 12 is heated by a 
lamp heater 13 to about 150.degree. C. A plurality of, for example, 25 
sheets of silicon wafers 14, i.e, substrates to be treated, on which 
resist patterns each of a diameter of 150 mm, for example, are formed are 
held in a wafer holder 15 and they are immersed in the treatment liquid 
12. The cleaning step and the resist removing step are completed by 
immersing the wafers 14 in the treatment liquid 12 for about 15 minutes. 
About 500 sheets of wafers 14 can be treated with the treatment liquid 12 
of 25 l. 
In an etching step of a glass layer, an ammonium fluoride (NH.sub.4 F) or a 
diluted hydrofluoric acid (HF) is used as the treatment liquid 12. In an 
etching step of a silicon layer, a solution of organic alkali is used as 
the treatment liquid 12. In order to remove an oxide film formed on the 
rear surface of the silicon wafer by an etching step, the wafer 14 is 
immersed in the treatment tub 11 with the main surface of the wafer being 
entirely covered by the resist. In addition, SiO.sub.2 can be deposited on 
a wafer by using the tub 11 as shown in FIG. 1, in which Al is dissolved 
in a saturated solution of H.sub.2 SiF.sub.6. When a liquid crystal 
display apparatus is manufactured, a larger chemical treatment tub 11 is 
used since larger wafers are used. 
FIG. 2 is a crosssectional view showing an apparatus for plating a silicon 
wafer. A plating of a silicon wafer with Au bumps for use in TAB (Tape 
Automated Bump) process will be described with reference to FIG. 2. A 
plating solution tub 21 is filled with an Au plating solution 22 and 
heated to 60.degree. to 70.degree. C. A wafer 23 and an electrode 24 are 
placed opposite each other in the Au plating solution 22. A direct power 
source 25 supplies a current to plate the wafer 23. A power feeding 
portion 26 is provided at an end of the wafer 23. 
Next, a deposition treatment on the silicon wafer will be described with 
reference to FIG. 3. To increase adhesion force between a positive 
photoresist and a wafer 33, a deposition treatment using a saline coupling 
agent such as HMDS (hexamethylenedisilane) is generally performed before 
the resist is applied to the wafer. In the deposition treatment, an HMDS 
liquid 32 and a wafer 33 are placed in a vessel 31 and then the vessel 31 
is sealed hermetically. The HMDS liquid 32 is heated by a heating means 34 
to be vaporized, vapor 35 of the HMDS liquid 32 forms an HMDS film on the 
wafer 33. In this way, the treatment of the wafer with coupling agent is 
completed. 
FIG. 4 is a crosssectional view showing a treatment apparatus using a spray 
nozzle. First, a method of developing a positive photoresist will be 
described. A silicon wafer 41 is mounted on a rotary chuck 42 and fixed 
thereto. In a development treatment, the wafer 41 is rotated to be 
developed while a treatment liquid i.e., a developer, is being sprayed on 
the pattern-exposed resist on the wafer 41 by a spray nozzle 44. 
Otherwise, a developer may be dropped from the nozzle 44 and deposited on 
the wafer 41 by means of a surface tension, to develop the photoresist in 
a static state. Next, a method of applying photoresist will be described. 
In FIG. 4, a treatment liquid 43, i.e., photoresist, is dropped from the 
nozzle 44 instead of a developer and deposited on the wafer 41. 
Thereafter, the wafer 41 is rotated by the rotary chuck 42. As a result, 
superfluous photoresist is scattered and a photoresist layer of a desired 
thickness is applied to the wafer 41. 
Regarding the treatments of the wafer 14 immersed in the chemical treatment 
tub 11, as shown in FIG. 1, the same treatment liquid 12 is always used 
several times since a great amount of the treatment liquid 12 is required. 
If the wafer 14 or the wafer holder 15 is contaminated, the contaminant is 
dissolved into the treatment liquid 12. Thus if the contaminated treatment 
liquid 12 is used to treat another wafer 14, then the wafer 14 is also 
contaminated. This is called cross-contamination. The treatment liquid 12 
should be changed for every treatment to prevent this contamination. Hence 
this method is impractical because of its high cost. Moreover, even if the 
treatment liquid 12 is changed for every treatment, contaminant on the 
rear surface of the wafer 14 may be attached to the main surface of the 
wafer 14. Hence, it is impossible to prevent the cross-contamination. In 
addition, a serious accident may occur if the treatment tub 11 is damaged 
since a great amount of the treatment liquid 12 is used in the treatment 
tub 11. Thus, the method has a problem in safely. 
In the plating of the wafer 23, as shown in FIG. 2, the rear surface of the 
silicon wafer 23 must be covered by the resist or the like, so that it is 
not plated. For this purpose, additional treatment steps are required. 
Moreover, the power feeding portion 26 is plated with Au since it is 
immersed in the plating solution 22 and therefore it is impossible to 
successively treat a number of wafers 23. In addition, since a great 
amount of the plating solution 22 must be used, a number of wafers 23 may 
be treated at a time to save cost. In such case the cross-contamination is 
unavoidable as in the case of the treatment shown in FIG. 1. Depending on 
the cause of the contamination, a quality of the plating cannot be 
duplicated. 
In the deposition treatment shown in FIG. 3, the HMDS film is formed 
unnecessarily on the rear surface of the wafer 33. In the subsequent 
steps, dusts may be adhered to the HMDS film on the rear surface, 
resulting in occurrence of particles or contamination. Moreover, the HMDS 
may be deposited thickly on the inner wall of the closed vessel 31. Thus 
the thick HMDS film may peeled off to cause the particles. Moreover, when 
the whole space of the vessel 31 is filled with the HMDS vapor, it is 
difficult to make the HMDS concentration in the vessel 31 uniform. 
Therefore, the thicknesses of the HMDS films formed on the wafer 33 may be 
varied. 
In the development treatment by the apparatus shown in FIG. 4, when the 
development is performed with the developer sprayed by the spray nozzle 44 
on the rotating wafer 41, a radial nonuniformity in the developer is 
occurred. Further, in case the developer is dropped from the nozzle 44 on 
the stationary wafer 41, the nonuniformity in the developer occurs less. 
However, if the developer spreads slowly on the surface of the wafer 41, 
another nonuniformity in the developer may easily occur. For this reason, 
it is desirable that the developer be spread on the surface of the wafer 
41 as quickly as possible. However, if the developer is spread too 
quickly, the surface tension of the developer is lost and then the 
developer cannot stay on the wafer 41. Thus the developer cannot be held 
on the surface of the wafer 41. Moreover, if the wafer is not placed 
horizontally, or vibrated or swayed due to wind, mechanical vibration, 
etc, the developer may also overflow the wafer 41. Moreover, when the 
diameter of the wafer 41 is as large as 200 mm or more, it is difficult to 
hold the developer on the wafer only by the surface tension. 
In the photoresist applying treatment by the apparatus shown in FIG. 4, 
when the wafer 41 is rotated to scatter the superfluous resist, the 
solvent in the resist volatilizes. As a result, the viscosity of the 
resist increases. Thus, if the solvent volatility speed do not balance 
with the resist scattering speed, the resist film may undulate with the 
thickness thereof being greatly varied. This is called striation. To 
minimize the striation, a greater amount of the resist 43 is deposited on 
the wafer 41, or the rotation speed or acceleration of the wafer 41 is 
increased, for example. However, the striation cannot be overcome by these 
measures only as wafers 41 have become lager and larger. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a method of treating a 
substrate with a small amount of a treatment solution efficiently with 
safety and without an influence of cross-contamination and an apparatus 
for the same. 
A method of treating a substrate of the present invention comprises the 
steps of placing treatment liquid holding means having a number of through 
holes in parallel with a treatment surface of a substrate; adjusting the 
distance between said treatment surface of the substrate and a surface of 
said treatment liquid holding means which faces said treatment surface, 
thereby forming a space therebetween; and filling the space with a 
treatment liquid and keeping the treatment liquid only on said treatment 
surface of the substrate by the surface tension of the treatment liquid. 
An apparatus of treating a substrate of the present invention comprises: 
means for holding the substrate to be treated; means, a plane of which 
faces a treatment surface of said substrate such that a space is formed 
therebetween, for causing a treatment liquid to be held only on the 
treatment surface by utilizing surface tension of the treatment liquid; 
and means for supplying the treatment liquid to said space. 
According to the present invention, an extremely small amount of a 
treatment solution suffices for the treatment since the treatment solution 
can be applied to only the treated surface of the substrate. In addition, 
the cross-contamination can be perfectly suppressed since a fresh 
treatment solution can be used in every treatment instead of the used 
treatment solution. The treatment can also be performed with safety at a 
low cost. 
Additional objects and advantages of the invention will be set forth in the 
description which follows, and in part will be obvious from the 
description, or may be learned by practice of the invention. The objects 
and advantages of the invention may be realized and obtained by means of 
the instrumentalities and combinations particularly pointed out in the 
appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Methods and apparatuses for treating a substrate according to embodiments 
of the present invention will be described in detail with reference to the 
accompanying drawings. 
FIG. 5A is a crosssectional view schematically showing a substrate 
treatment apparatus according to a first embodiment of the present 
invention. The substrate treatment apparatus of the first embodiment has 
been developed to treat the main surface (upper surface) of the substrate. 
A substrate holder 111 is formed of quartz and constituted by a peripheral 
portion 111a and a central supporting portion 111b which is lower than the 
peripheral portion 111a. A silicon wafer 112 having a diameter of, for 
example, 150 mm is mounted on the supporting portion 111b of the substrate 
holder 111. A treatment liquid holder 113 is mounted on the peripheral 
portion 111a thereby defining an interval 114 between holder 113 and wafer 
112. The holder 113 has through holes 110. The holder 113 is immersed in a 
treatment liquid 115 and the through holes 110 are filled with the liquid 
115. 
The treatment liquid holder 113 is made of a carbon disk, for example, 
having a diameter of 170 mm and a thickness of 2 mm. FIG. 5B is a plan 
view of treatment liquid holder 113. Through holes 110 having a diameter 
of 1.5 mm are formed at intervals of 3 mm on a substantially overall 
portion of a circle having a diameter of 150 mm in the carbon disk. The 
through holes 110 are not provided on an area of the holder 113 
corresponding to an orientation flat (OF) portion of the wafer 112. As 
shown in FIG. 5A, the difference between the heights of the peripheral 
portion 111a and the supporting portion 111b of the substrate holder 111 
is determined in accordance with the thickness of the wafer 112, the 
surface tension of the treatment liquid 115 and the like, such that the 
interval 114 of, for example, 0.5 mm is formed between the holder 113 and 
the wafer 112, as is shown in FIG. 5C, which is an enlarged 
cross-sectional showing a portion of the holder shown in FIG. 5B. Hence, 
the treatment liquid 115 is held in the interval 114 and does not overflow 
the wafer 112. The interval 114 can be changed in accordance with the 
viscosity of the treatment liquid 115. For example, if the liquid 115 is 
water the interval 114 is about 0.5 mm, and if the liquid is a solution of 
a high viscosity such as sulfuric acid the interval 114 is about 1 mm. 
In the apparatus shown in FIGS. 5A, 5B and 5C a sufficient amount of 
treatment liquid 115 can be held in the space between the holder 113 and 
the wafer 112 since the holder 113 has a number of through holes 110. 
Moreover, the holder 113 can be easily removed from the wafer 112 since 
air can flow into the interval through the through holes 110 by lifting up 
the holder 113. If the holder 113 may be made of porous material, the same 
effect can be obtained. Needless to say, the holder 113 should be formed 
of a material which is not deteriorated by the treatment liquid 115. 
Further, it is desirable that the surfaces of the holder 113 have been 
processed with Teflon or the like to increase both the surface tension of 
the liquid 115 and the chemical resistance of the holder 113. If possible, 
the side surface of the wafer 112 are also processed in the same manner. 
The holder 113 may be formed of knit of carbon or glass fibers, or 
paper-like material. In such case the holder 113 can be removed from the 
wafer 112 much easier since it is bendable. Furthermore, the holder 113 
may be made of unbendable sticks connected by threads or suitable coupling 
means so as to form a raft-like member. 
A treatment of removing resist or cleaning a wafer by means of the 
apparatus of FIG. 5A using a mixed solution of H.sub.2 SO.sub.4 and 
H.sub.2 O.sub.2 as a treatment liquid 115 will now be described. H.sub.2 
OS.sub.4 and H.sub.2 O.sub.2 are mixed in the ratio 10:1. Resist is 
deposited on the main surface, i.e., the upper surface of the wafer 112 to 
which the holder 113 is opposed. The holder 113 is placed on the wafer 112 
to hold a treatment liquid 115. Thus lamp heater 116 positioned below the 
substrate holder 111 is turned on, thereby heating the holder 113 made of 
carbon, which easily absorbs infrared radiation. As a result, the 
treatment liquid 115 is heated quickly and the resist is removed from the 
wafer 112 at a high rate. The temperature of the heater 116 in this step 
is, for example, 150.degree. to 200.degree. C. The resist removing 
treatment is completed within 2 to 3 minutes. After the treatment is 
completed, the holder 113 is lifted up and the wafer 112 is removed from 
the substrate holder 111 and another wafer to be treated is placed 
thereon. Then, the above-described steps are repeated. Instead of mounting 
the holder 113 immersed by the treatment liquid 115 on the wafer 112, the 
treatment liquid 115 may be dropped on the holder 113 which has been 
placed on the wafer 112. If the contaminant generated when the resist is 
removed is adhered to the holder 113, the cross-contamination may occur. 
To prevent this, the holder 113 may be cleaned, if necessary. In this 
case, the process will not delay if a plurality of holders 113 are used 
sequentially. 
A treatment of removing an Si.sub.3 N.sub.4 film formed on the wafer 112 by 
means of the apparatus of FIG. 5A using a heated phosphoric acid (H.sub.3 
PO.sub.4) as the treatment liquid 115 will then be described. The 
treatment process is the same as the resist removing treatment as 
described above. However, according to the preferred embodiments of the 
present invention, the treatment can be performed with safety since a very 
small amount of phosphoric acid is used. In addition, the Si.sub.3 N.sub.4 
film can be removed from the wafer 112 at a cost lower than that required 
in a conventional treatment method using plasma. Moreover, the wafer 112 
is not affected and damaged by the treatment liquid 115 at all. 
The apparatus shown in FIG. 5A is also applicable to etching an SiO.sub.2 
film with an ammonium fluoride (NH.sub.4 F) or a diluted hydrofluoric acid 
(HF), or to etching silicon with an organic alkali solution. In these 
treatments, an SiC film formed by a high-purity CVD method is used as the 
holder 113. 
In the first embodiment shown in FIG. 5A, the treatment liquid holder 113 
has an area entirely covering the silicon wafer 112. However, the holder 
113 may be constructed to have an area covering only a portion of the 
silicon wafer 112. In this case, the overall surface of the wafer 112 can 
be covered by sliding the holder 113 over the wafer 112. 
FIG. 6A is a crosssectional view schematically showing a substrate 
treatment apparatus 211 according to a second embodiment of the present 
invention. FIG. 6A shows holder 214, spot facing holes (blind holes) 212, 
through holes 213, projections 215, treatment liquid 216, and wafer 217. 
FIG. 6B is an enlarged crosssectional view showing a portion A shown in 
FIG. 6A. The apparatus of the second embodiment is developed to treat the 
rear surface, i.e., lower surface of a wafer 217. 
A treatment liquid holder 214 is constituted by a carbon plate having a 
diameter of 150 mm and a thickness of 10 mm (FIG. 7A). Spot facing holes 
(blind holes) 212 having a diameter of 2 mm and a depth of 2 mm are formed 
in matrix at a 4 mm pitch on a substantially entire portion of the holder 
214 (FIG. 7B). In the holder 214, through holes 213 of a diameter of 1 mm 
are formed in about 30% of all the spot facing holes 212 at their bottoms 
(FIG. 7C). Projections 215 for supporting the wafer 217 are formed at 
intervals in the peripheral portion of the holder 214. The height of the 
projections 215 is determined in accordance with the amount of the 
treatment liquid 216 required for treating the wafer 217, the surface 
tension of the liquid 216 and the like. For example, three projections 215 
of 1.5 mm height are formed on the peripheral portion of the holder 214. 
To increase the surface tension of the liquid 216 on the holder 214, an 
SiC film is deposited about 50 .mu.m thickness entirely on the holder 214 
by CVD method. 
Now, a treatment of removing an oxide film formed on the rear surface of 
the wafer 217 by means of the apparatus of FIG. 6A will now be described. 
A solution 216 of the ammonium fluoride (NH.sub.4 F) is dropped on the 
spot facing holes 212 of the treatment liquid holder 214 so as to slightly 
swell thereon (FIG. 7D). Next, the wafer 217 is placed on the projections 
215 such that the treatment surface i.e., the rear surface of the wafer 
217 is brought into contact with the NH.sub.4 F solution 216 (FIG. 7E). 
The NH.sub.4 F solution 216 thus extends over the entire rear surface of 
the wafer, as is shown in FIG. 7E. Although the treatment liquid 216 
enters the through holes 213 while it is dripping in the spot facing holes 
212, it does not leak below owing to the surface tension. However, it is 
desirable that the amount of drip should be adjusted such that the 
treatment liquid 216 does not leak out of the through holes 213 when the 
rear surface of the wafer 217 is brought into contact with the treatment 
liquid 216. It is also desirable that the wafer 217 be inclined to prevent 
air from entering between the wafer 217 and the treatment liquid 216, so 
that a bubble may not be formed. When the treatment is completed and the 
wafer 127 is lifted up, since air can flow into the space between the 
wafer 217 and the holder 214 through the through holes 213, the wafer 217 
can be ripped off from the holder 214 relatively easily. 
FIG. 8 is a crosssectional view schematically showing a substrate treatment 
apparatus according to a third embodiment of the present invention. In the 
third embodiment, a treatment liquid holder 214 is the same as that of the 
second embodiment shown in FIG. 6A. A closed space 251 communicating with 
a space between the holder 214 and the wafer 217 by the through holes 213 
is provided beneath the holder 214. A pressure control mechanism for 
controlling the pressure in the closed space 251 is connected to the space 
251. The pressure control mechanism is constituted by, for example, an 
N.sub.2 cylinder 254 and a pressure control valve 255. The pressure 
control mechanism can be utilized for controlling the pressure in the 
closed space 251 to bring the treatment liquid 216 into contact with the 
treatment surface of the wafer 217, or increasing or decreasing the 
pressure in the space 251 to apply variations to the treatment liquid 216 
so that the spread of the treatment liquid 216 can be accelerated. 
Furthermore, the pressure control mechanism can be utilized for 
controlling the pressure in the space 215 when the wafer 217 is lifted up 
from the holder 214, so that gas can easily flow through the through holes 
213. Otherwise, a treatment liquid supplying mechanism may be connected to 
the closed space 251, and the space 251 may be filled with a treatment 
liquid 216. In this case, the liquid 216 is supplied to the spot facing 
holes through the through holes 213, and the used treatment liquid 216 is 
collected to the supplying mechanism after completion of the treatment. An 
ultrasonic oscillator 253 for vibrating to the treatment liquid 216 may be 
provided on the bottom 252 of the closed space 251, if necessary. 
Moreover, a temperature control mechanism (not shown) may be provided for 
controlling both temperatures of the treatment liquid 216 and the wafer 
217. 
FIG. 9 is a crosssectional view showing a substrate treatment apparatus 
according to a fourth embodiment of the present invention. The apparatus 
of the fourth embodiment is developed for use in plating a wafer. A 
substrate holding vessel 311 comprises an outer peripheral portion 311a 
for hermetically sealing the vessel 311 and a trapezoid supporting portion 
311b formed at its center. The vessel 311 is formed of, for example, 
quartz having a diameter of 175 mm. The difference between the heights of 
the outer peripheral portion 311a and the supporting portion 311b is 
determined in accordance with the thickness of a wafer 314 to be treated, 
the surface tension of a plating solution 322 and the like. Plating 
electrodes 315 are provided on the surface of the supporting portion 311b. 
A treatment liquid holder 312 has substantially the same diameter as the 
peripheral portion 311a of the substrate holding vessel 311, and it is 
connected to the peripheral portion 311a with an O ring 313 interposed 
therebetween thus forming a closed space. The holder 312 is made of, for 
example, stainless steel, and includes a space 320 for holding a 
predetermined amount of a treatment liquid 322. The lower surface of the 
holder 312, which faces the wafer 314, is processed with Pt, and all the 
other surfaces thereof is processed with Teflon to increase the chemical 
resistance with respect to the plating solution 322. A number of through 
holes 309 are formed in the bottom of the holder 312. A gas supplying 
mechanism 318 and a drain (gas exhausting) mechanism 319 are connected to 
the vessel 311 to control the pressure therein. A treatment liquid 
supplying mechanism 321 communicates with the space 320 in the holder 312 
and controls the pressure of the treatment liquid in the space 320. A 
direct current power source 323 is connected to the holder 312 and the 
electrodes 315 adhered to the supporting portion 311b. An ultrasonic 
oscillator 324 is mounted on the upper surface of the holder 312. A 
heating lamp 325 is placed beneath the vessel 311. A vacuum chuck 
mechanism 316 may be connected to the vessel 311 to ensure the contact 
between the wafer 314 and the electrodes 315. In addition, notches or 
slits 317 may be formed in the supporting portion 311b so that the wafer 
314 can be easily mounted on or removed from the supporting portion 311b. 
A treatment of plating a silicon wafer 314 with an Au bump for use in the 
TAB process by means of the apparatus of FIG. 9 will now be described. 
First, a wafer 314 is placed on the supporting portion 311b of the 
substrate holding vessel 311. Next, a plating solution 322 is supplied 
from a plating solution supplying mechanism 321 to a space between the 
wafer 314 and the holder 312 via the through holes 309, while the pressure 
in the vessel 311 and the pressure of the treatment wafer 314 is balanced. 
The plating solution 322 does not overflow the wafer 314 owing to the 
surface tension of the solution 322 on the holder 312 and the wafer 314, 
as shown in FIG. 9. A direct current of a predetermined amount is supplied 
from the direct current power source 323 to the holder 312 and the 
electrodes 315 for a predetermined period of time. As a result, the wafer 
314 is plated with Au. At that time, it is possible to apply ultrasonic 
vibrations to the plating solution 322 by means of the ultrasonic 
oscillator 324, thereby facilitating the circulation of the plating 
solution 322. Moreover, during the plating process, the plating solution 
322 existing in the space between the holder 322 and the wafer 314 can be 
replaced by the solution stored in the space 320 by means of the plating 
solution supplying mechanism 321. Furthermore, if necessary, the wafer 314 
may be heated by the heating lamp 325 and/or a heated plating solution 322 
may be supplied to the vessel. 
According to the fourth embodiment, since the rear (lower) surface of the 
wafer 314 is not contacted with the plating solution 322, it is not 
stained by contaminant in the solution and the electrodes are not plated 
with Au, unlike in the conventional treatment apparatus. Hence, Au bump 
plating is carried out satisfactorily. In addition, the fourth embodiment 
is advantageous in safety since the plating solution is held in the closed 
space and vapor of the plating solution 322 does not flow outside the 
apparatus. 
FIG. 10 is a crosssectional view showing a substrate treatment apparatus 
according to a fifth embodiment of the present invention. The apparatus of 
this embodiment is adapted for use mainly in development of a wafer. This 
embodiment differs from the fourth embodiment shown in FIG. 9 in that a 
temperature controller 340 for controlling the temperature of the wafer 
314 is provided in place of the heating lamp 325. A developer is used as a 
treatment liquid 322. The direct current power source 323 and the plating 
electrodes 315 are not provided. 
In the fifth embodiment, since the developer can instantaneously cover a 
surface of the wafer, uniform development is achieved without a 
nonuniformity of the developer. Further, even if the wafer 314 is larger 
than 200 mm in diameter, uniform development can be also achieved without 
any problem. If a treatment liquid 322 wherein Al or the like is dissolved 
in a saturated solution of H.sub.2 SiF.sub.6 is used instead of developer, 
an SiO.sub.2 film can be deposited on the wafer 314. In this case, the 
deposition is performed at a high rate without abnormal deposition since 
only the wafer 314 can be heated to 60.degree. to 80.degree. C. 
FIG. 11 is a crosssectional view schematically showing a substrate 
treatment apparatus according to a sixth embodiment of the present 
invention. The apparatus of this embodiment is suitable for treatment 
using a silane coupling agent, which is used to adhere photoresist to a 
wafer. A number of through holes 341 are formed in the plane of a 
treatment liquid holder 312, which faces a wafer. The lower surface of the 
holder 312 is covered by a porous member 351 so that only vapor of the 
silane coupling agent can pass therethrough. The porous member 351 may be 
made of paper, cloth, or porous material formed of carbon, ceramic, etc. 
The silane coupling agent may be suitably diluted and then directly applied 
to a wafer. However, it can be applied to a wafer by vapor deposition, in 
which case the vapor in the space in the holder 312 is applied through the 
through holes 341 and the porous member 351 to the wafer. According to the 
sixth embodiment, no particles are produced since the silane coupling 
agent is not applied to the rear surface of the wafer. 
FIG. 12 is a crosssectional view showing a substrate treatment apparatus 
according to a seventh embodiment of the present invention. The apparatus 
of the seventh embodiment is suitable for treatments such as photoresist 
application, etc. A wafer supporting chuck 411 is rotatable and movable 
upward and downward. The chuck 411 comprises a fixing means such as a 
vacuum chuck. The apparatus also comprises a holder 413 for holding the 
photoresist above the supporting chuck 411 and a space which can store the 
photoresist. A resist supplying mechanism 414 communicates with the space. 
The plane of the holder 413 facing the wafer 412 has a porous member 416. 
The porous member 416 is made of, for example, a Teflon sheet. 
A treatment of applying the photoresist to the wafer by means of the 
apparatus shown in FIG. 12 will now be described. First, the wafer 412 is 
fixed on the wafer supporting chuck 411. The wafer 412 is brought near the 
porous member 416 filled with the photoresist 415 by moving the chuck 411 
upwardly without contacting with the member 416. In this state, the 
photoresist 415 is transferred from the porous member 416 to wafer 412, 
thereby forming the resist layer on the wafer 412. Thereafter, the wafer 
supporting chuck 411 with the wafer 412 disposed thereon is moved downward 
and stopped, then rotated slowly. As a result, superfluous resist 415 is 
scattered. Thus, a resist layer of a desired thickness is formed on the 
wafer 412. 
According to the seventh embodiment, since the holder 413 positioned above 
the wafer 412 holds a large amount of photoresist 415 and thus the resist 
solvent volatilizes from the photoresist 415, the atmosphere surrounding 
the wafer 412 is full of the resist solvent when the wafer 412 is rotated 
and the superfluous photoresist is scatttered. Hence, the resist on the 
wafer 412 hardly dries, and the resist layer of a desired thickness can be 
obtained by rotation at a low speed. Moreover, the amount of resist used 
in the treatment is 1/3 to 1/10 that required in the conventional 
treatment apparatus. However, if the resist solvent concentration in the 
atmosphere surrounding the wafer 412 remains high for a long period of 
time, the photoresist 415 does not dry at all and a resist layer of an 
uniform thickness cannot be obtained. To prevent this, when the resist 
layer of a desired thickness is obtained, the wafer supporting chuck 411 
is moved further downward to separate from the holder 413, thereby 
decreasing the resist solvent concentration in the atmosphere surrounding 
the wafer 412. Needless to say, the apparatus shown in FIG. 12 is also 
applicable for a treatment using a silane coupling agent and a development 
treatment. 
FIG. 13 is a crosssectional view showing a substrate treatment apparatus 
according to a eighth embodiment of the present invention. The apparatus 
of the eighth embodiment is suitable for treating a large-sized substrate 
such as a glass plate for use in a liquid display device. A glass 
substrate 511 is disposed on and can be transferred by a substrate 
transfer roller 512. An endless belt 513 made of cloth resistant to a 
treatment liquid is positioned above the substrate 511, and can be rotated 
by a plurality of rollers 514 for rotating the belt. The endless belt 513 
may be formed of, for example, Teflon paper, or mesh or cloth of so-called 
engineering plastic fiber such as polyamide and polyether ketone. The 
treatment apparatus of this embodiment also comprises a treatment liquid 
supplying mechanism 515 for supplying a treatment liquid to the cloth 
belt. The endless belt 513, the roller 514 for rotating the belt, and the 
treatment liquid supplying mechanism 515 constitute a treatment liquid 
holder 516, which is placed in proximity to the substrate 511, so that the 
main surface of the substrate touches the treatment liquid 523. The 
treatment is performed while the substrate 511 is moving. A cleaning 
mechanism 517 removes the excessive treatment liquid 523 remaining on the 
surface of the substrate after the treatment is completed. The cleaning 
mechanism 517 is constituted by a water supplying portion 519 for 
supplying water to the central portion of the mechanism and a 
low-pressured collecting portion 520 for collecting the used water and the 
remaining treatment liquid. The water supplying portion 519 includes a 
porous member 521 at the distal end for controlling the amount of water to 
clean the substrate surface. The apparatus of the embodiment further 
comprises a wiper mechanism 522 formed of cloth having water absorption 
properties to remove remaining water from the substrate. If necessary, a 
drying mechanism may be further provided with this embodiment, a large 
substrate 511 can be efficiently treated with a small amount of treatment 
liquid. 
With the treatment apparatus and method of the present invention, a 
substrate is treated efficiently and safely with a small amount of 
treatment fluid without producing contaminant from the rear surface of the 
substrate. 
Additional advantages and modifications will readily occur to those skilled 
in the art. Therefore, the invention in its broader aspects is not limited 
to the specific details, representative devices, and illustrated examples 
shown and described herein. Accordingly, various modifications may be made 
without departing from the spirit or scope of the general inventive 
concept as defined by the appended claims and their equivalents.