Apparatus for forming liquid film

Details Apparatus for forming liquid film Apparatus for forming liquid film

2002-03-07

2003-12-09

Edwards, Laura (Department: 1734)

Coating apparatus

Control means responsive to a randomly occurring sensed...

C118S664000, C118S683000, C118S684000, C118S708000, C118S712000, C118S323000

Reexamination Certificate

active

06660091

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a technique for forming a liquid film by supplying a liquid onto a substrate to be processed, and more specifically, to an apparatus and method of selectively forming the liquid film on the substrate.
In a manufacturing step of the semiconductor device, a liquid such as a resist or an SOG (Spin on Glass) solution is coated on a substrate. In a spin-coating method which has been conventionally used in a lithographic process to coat the liquid on the substrate, almost all amount of the liquid supplied onto the substrate is discarded out of the substrate and the remainder (several %) held on the substrate is used in forming a film. Therefore, a large amount of the liquid (such as a chemical agent) is wasted. Furthermore, a large amount of the chemical agent is released outside, negatively affecting the environment. In the case where a rectangular substrate or a large-aperture disk-form substrate (12 inches or more) is used, a turbulence is generated around the substrate, with the result that the obtained film is not uniform at outer peripheral portion thereof.
As a method of coating the chemical agent uniformly over the main surface of a substrate while the chemical agent is not wasted, Japanese Patent Application KOKAI Publication No. 2-220428 discloses a method of forming a uniform film by supplying a resist from a plurality of nozzles arranged in line and then blowing a gas or a liquid to the film formation surface behind the resist. Japanese Patent Application KOKAI Publication No. 6-151295 discloses a method of forming a uniform film by splaying a resist to a substrate from a plurality of spray holes formed in a rod. Japanese Patent Application KOKAI Publication No. 7-321001 discloses a method of forming a uniform film by moving a spray head having numeral spray holes for spraying a resist relative to a substrate. All of the coating apparatuses mentioned are directed to the formation of a uniform film by moving output nozzles or spray nozzles arranged laterally in line in a scanning manner along a substrate surface.
To use the chemical agent without waste, a method has been proposed in which a liquid film is formed by supplying a liquid from a nozzle selectively to a film formation region of the substrate. As such a selective film formation method using a liquid supply nozzle, known is a method using an accurate coating nozzle (manufactured by EFD CO., Ltd.) in which output of the liquid can be controlled in an ON/OFF manner.
In the method using the accurate coating nozzle, a liquid
13
is shut out by driving a valve such as a needle
171
or a screw
181
, which is provided within a nozzle positioned above an output port
172
, as shown in
FIGS. 1 and 2
.
This system has a problematic phenomenon where particles are generated by friction between the valve and the liquid when the valve is driven, and the particles are delivered to the substrate by being contained in a liquid supplied dropwise onto the substrate when the valve is opened. This system has another problematic phenomenon where pressure applied to the liquid slightly changes immediately after the valve is opened and thereby a pulsation flow occurs. Due to the pulsation flow, the thickness of the formed film changes.
More specifically, if a liquid film is selectively formed on the substrate while controlling output of the liquid by operating the valve arranged before the output port, as described, a problem of liquid-film contamination with the particles comes up. In addition, if the pulsation flow occurs, the liquid film is formed non-uniformly in thickness.
If the substrate has an uneven surface due to various patterns formed thereon, the following problems come up.
As shown in
FIG. 3
, if constructs
102
are formed on a substrate
101
and the ratio of the depressed portion is different depending on regions of the substrate surface, the thickness of films
103
a
,
103
b
, and
103
c
differs. In this case, the surfaces of the films are not formed uniform. Then, if the structure shown in
FIG. 3
is subjected to a reflow processing, the resultant films, for example, insulating films
104
a
,
104
b
, and
104
c
, can be flattened, as shown in FIG.
4
A.
However, depending upon the difference in ratio of the depressed portion, the insulating films
104
a
,
104
b
,
104
c
differ in surface level (height). Therefore, when resist patterns
106
a
-
106
c
are formed on the insulating films
104
a
-
104
c
with an antireflection film
105
interposed between them and exposed to light, some of them are defocused. The resist patterns
106
a
-
106
c
obtained after the light exposure have a problem in that line widths thereof drastically vary each other as shown in FIG.
4
B.
In brief, as described, the spin-rotation method has a problem in that almost all amount of liquid supplied dropwise on the substrate is wasted. On the other hand, the method of supplying the liquid dropwise onto the substrate has a problem in that the formed liquid film differs in height (level) from the substrate depending upon projections and depressions of the pattern formed on the substrate. In other words, the formed liquid film is non-uniform in thickness measured from the substrate surface.
BRIEF SUMMARY OF THE INVENTION
A first object of the present invention is to provide an apparatus and method for selectively forming a liquid film on a substrate in a uniform thickness while suppressing contamination of the liquid film with impurities. A second object of the present invention is to provide a method of forming a liquid film having a flat surface even on both projections and depressions by coating a liquid on a substrate efficiently without influence from the projections and depressions attributed to patterns formed on the substrate.
The present invention is constituted as described below to attain the first object.
(1) According to the present invention, there is provided an apparatus for forming a film, comprising:
a liquid output portion arranged above a substrate in which a predetermined film formation region and a predetermined non-film-formation region are defined, for continuously outputting a liquid to the substrate in a constant amount;
a moving portion for relatively moving the liquid output portion and the substrate; and
a liquid shut-out portion arranged between the liquid output portion and the substrate, for shutting out supply of the liquid to the non-film-formation region when at least one of the substrate and the liquid output portion is moved and ready to supply the liquid output from the liquid supply portion to the non-film-formation region.
Preferred embodiments of constitution (1) will be described below.
The liquid shut-out portion comprises a liquid suction portion for sucking the liquid output from the liquid output portion, from a side of a liquid flow, and a liquid collection portion for collecting the liquid sucked.
The liquid shut-out portion comprises a gas blow-out portion for blowing out a gas to a side of a liquid output from the liquid output portion and a liquid collection portion arranged so as to sandwich the output liquid with the gas blow-out portion below the gas blow-out portion, for collecting the liquid to which the gas is blown out.
The liquid shut-out portion comprises
a light emitting portion for emitting light for initiating a reaction of a gas generating material;
a light controlling portion for controlling a direction of light emitted from the light emitting portion;
a gas blow-out portion having the gas generating material for generating a gas upon receipt of light controlled by the light controlling portion and blowing out the gas generated to a side of the liquid output from the liquid output portion; and
a liquid collection portion arranged so as to sandwich the output liquid with the gas blow-out portion, for collecting the liquid to which the gas is blown out.
The liquid shut-out portion comprises
a shut-out plate arranged between the liquid output portion and the substrate, for changing a flow of the liquid output form

Affiliated with

Also associated with

Rating

Apparatus for forming liquid film does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Apparatus for forming liquid film, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for forming liquid film will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3153465