JP2000091185A - Substrate processing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a substrate processing device and method capable of enhancing line width uniformity in a resist film after being developed. SOLUTION: A substrate W provided for heating in a heating process part HP2 as a bake part before alignment is mounted on a hot plate 50. At the time of heating, an air current of nitrogen gas is supplied from a gas blowoff hole 52a of a bake cover 52 to the substrate W. The gasflow is selectively exhausted from either an exhaust port 51 or an exhaust port 51b. Accordingly, a flow in a specific direction is formed on the substrate W at the time of heating alignment. When heating after alignment as a post-process is performed for this substrate W, a flow of the gas in an inversive direction to the specific direction at the time of heating before alignment is formed. Aspects of a temperature slope within a substrate face are mutually reversed between the aspect at the time of heating before alignment and that at the time of heating after alignment and it is possble to enhance line width uniformity in a resist film after being developed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate, a glass substrate for a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk or the like (hereinafter simply referred to as "substrate"). The present invention relates to a substrate processing apparatus and method for performing a pre-exposure bake and a post-exposure bake.

[0002]

2. Description of the Related Art Generally, for a substrate as described above,
A series of substrate processes is achieved by sequentially performing a resist coating process, an exposure process, a development process, and a heat treatment associated therewith. That is, a pre-exposure bake (hereinafter, referred to as "pre-bake") is performed on a substrate having a surface coated with a photoresist (hereinafter, simply referred to as "resist") before exposure. Then, after the substrate is subjected to an exposure process, a post-exposure baking process (hereinafter, referred to as “post-exposure bake”) is performed, and thereafter, a development process using a developing solution is performed. It is done.

[0003] Among the above, the pre-bake is performed to evaporate an excess solvent component in the applied resist and to strengthen the adhesion between the resist and the substrate. The post-exposure bake is performed for the purpose of activating a chemical reaction that causes a change in the dissolution rate in a developer due to the catalytic action of a product generated by a photochemical reaction at the time of exposure.

[0004] In each of these methods, a heat treatment is performed on a substrate at a predetermined temperature for a predetermined time, and is performed by a heat processing section provided with a hot plate. And
In the heat treatment section, an airflow is formed on the substrate so that the solvent evaporated from the resist does not diffuse to the surroundings as the substrate is heated, and the airflow is exhausted by the exhaust means.

[0005]

However, when an air current is formed on the substrate during the heat treatment, a temperature gradient is generated in the substrate. That is, a temperature difference occurs between a portion located on the upstream side of the air flow and a portion located on the downstream side in the plane of the substrate. When such a temperature gradient occurs, the uniformity of the in-plane temperature of the substrate is impaired, and as a result, the uniformity of the line width in the resist film after the development processing is impaired.

For this reason, attempts have conventionally been made to make the flow of air flow over the substrate uniform so as to maintain the uniformity of the in-plane temperature of the substrate during the heat treatment. Accordingly, it has been extremely difficult to make the flow of the air current uniform over the entire surface of the substrate and to maintain the uniformity of the in-plane temperature of the substrate.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a substrate processing apparatus and method capable of improving the line width uniformity of a resist film after development processing.

[0008]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a pre-exposure bake unit for performing a pre-exposure bake treatment on a substrate after resist application and before exposure, and a pre-exposure bake unit for post-exposure baking. A post-exposure bake unit for performing post-exposure baking, and a substrate processing apparatus including: a direction of airflow on the substrate during the pre-exposure baking, and a flow direction on the substrate during the post-exposure baking. The direction of the airflow is reversed.

According to a second aspect of the present invention, in the substrate processing apparatus according to the first aspect of the present invention, an air current is supplied to each of the pre-exposure bake section and the post-exposure bake section from above the substrate being heated. Supply ports, exhaust ports provided on one side and the other side of the substrate, respectively, for exhausting the supplied airflow, exhaust from the one exhaust port, and exhaust port on the other side Switching means capable of switching between and exhaust from, and during the pre-exposure bake section, while performing the evacuation from the one side exhaust port of the pre-exposure bake section, during the post-exposure bake section,
An exhaust is performed from the other exhaust port of the post-exposure bake section.

According to a third aspect of the present invention, in the substrate processing apparatus according to the first aspect, the pre-exposure bake unit includes:
A pre-exposure supply port for supplying an airflow to the substrate from one side on the side of the substrate during the heat treatment, and a pre-exposure exhaust port for exhausting the supplied airflow from the other side beside the substrate. A post-exposure supply port for supplying an airflow to the substrate from the other side of the substrate during the heat treatment, and the supplied airflow is exhausted from the one side of the substrate to the post-exposure bake section. And a post-exposure exhaust port.

According to a fourth aspect of the present invention, there is provided a substrate processing method for performing a predetermined processing including a heat treatment on a substrate,
(a) a pre-exposure heating step of performing pre-exposure baking while flowing an airflow in a first direction on the substrate after resist coating and before exposure, and (b) the first exposure process on the substrate before post-exposure development. And a post-exposure baking step of performing a post-exposure baking while flowing an airflow in a second direction opposite to the direction of b.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1. In order to solve the above-mentioned problem, that is, the problem of reduction in line width uniformity caused by airflow formation during heat treatment, the present inventor has conducted intensive studies, and as a result, Now that we have found such knowledge, we will explain it.

As described above, conventionally, attempts have been made to improve the line width uniformity by making the flow of the air flow on the substrate uniform, but the flow of the air flow on the substrate in the pre-bake and the post-exposure bake have been attempted. The relationship with the flow of the air current on the substrate has not been studied.

The inventors of the present invention have investigated the relationship. As a result, when the direction of the air flow on the substrate in pre-baking and the direction of the air flow on the substrate in post-exposure baking are reversed, the development is performed. It has been found that the line width uniformity of the processed resist film is improved.
That is, when the direction of the substrate in the pre-bake is the same as the direction of the substrate in the post-exposure bake, and the direction of the air flow on the substrate is opposite to each other, the line width uniformity is improved. This is because the temperature gradient in the substrate surface during the pre-bake and the temperature gradient in the substrate surface during the post-exposure bake are opposite to each other by reversing the direction of the airflow while keeping the direction of the substrate the same. Is considered to be the effect of

The present inventors have completed the present invention based on the above findings. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<2. Overall Configuration of Substrate Processing Apparatus> First, the overall configuration of the substrate processing apparatus according to the present invention will be described.
FIG. 1 is a diagram showing an overall configuration of a substrate processing apparatus according to the present invention. FIG. 1A is a plan view of the substrate processing apparatus,
FIG. 1B is a front view of the substrate processing apparatus. In FIG. 1, an XYZ orthogonal coordinate system is added to clarify the directional relationship. Here, the horizontal plane parallel to the floor is XY
The vertical direction is the Z direction.

As shown in FIG. 1, in the present embodiment, the substrate processing apparatus comprises an indexer I which carries in and out a substrate.
D, a plurality of processing units for performing processing on the substrate, and a unit arrangement unit MP in which substrate transporting means for transporting the substrate to each processing unit are arranged, and a substrate is loaded between an exposure apparatus (not shown) and the unit arrangement unit MP. / Interface IF provided for carrying out.

The unit disposition portion MP is provided with a chemical cabinet 11 at the lowermost portion for accommodating a pipe for supplying / discharging a processing liquid such as a resist.
In the corners, as a liquid processing unit for performing liquid processing on the substrate, a coating processing unit SC1, which performs a resist coating process while rotating the substrate,
SC2 (spin coater) and development processing units SD1 and SD2 (spin developer) for developing the exposed substrate are arranged. Further, above these liquid processing units, a multi-stage heat treatment unit 20 for performing heat treatment on the substrate is disposed at the front and rear of the apparatus. A cleaning liquid such as pure water is supplied to the substrate as a substrate processing unit between the coating processing units SC1 and SC2 on the front side (negative direction side in the Y direction) of the apparatus, and the substrate is rotationally cleaned. A cleaning section SS (spin scrubber) is provided.

The coating processing units SC1, SC2 and the developing processing unit S
A transport robot TR1 is disposed in a central portion of the apparatus between D1 and SD2 as a substrate transport means for accessing all the processing units in the vicinity and transferring the substrate to and from them. The transfer robot TR1 is movable in the vertical direction and is rotatable around a central vertical axis.

At the top of the unit arrangement section MP,
A filter fan unit FFU for forming a clean air downflow is provided. Immediately below the multi-stage heat treatment unit 20, a filter fan unit FFU that forms a downflow of clean air is provided on the liquid treatment unit side.

Next, FIG. 2 is a diagram for explaining an arrangement configuration of the processing unit of FIG. Above the coating processing unit SC1, a six-stage heat treatment unit is arranged as the multi-stage heat treatment unit 20. Among them, a cooling processing unit CP1 for performing a cooling process of the substrate is provided at a position of the first stage counted from the lowest stage, and the cooling processing unit CP is similarly provided for the second and third stages.
2 and CP3. The fourth stage is provided with an adhesion strengthening unit AH for performing an adhesion strengthening process on the substrate, and the fifth and sixth stages are provided with a heat treatment unit HP1 as a bake unit for performing a heat treatment on the substrate. , HP2 are provided.

A heat treatment unit having a six-stage structure is disposed above the coating treatment unit SC2 as the multi-stage heat treatment unit 20.
Among these, cooling processing units CP4 to CP6 are provided at the first to third stages from the bottom, and heating processing units HP3 to HP5 are provided at the fourth to sixth stages. ing.

Above the development processing section SD1, a multi-stage heat treatment section as a multi-stage heat treatment section 20 is arranged.
Of these, cooling processing units CP7 and CP8 are provided at the first and second stages from the bottom, and heating processing units HP6 and HP7 are provided at the third and fourth stages. I have. In the case of the apparatus of the present embodiment, the upper two stages are empty, but a heat treatment unit, a cooling treatment unit, or another heat treatment unit can be incorporated according to the application and purpose. .

A two-stage heat treatment section is also provided above the development processing section SD2 as the multi-stage heat treatment section 20.
Of these, the cooling processing unit C
P9 is provided, and a post-exposure bake plate portion PEB for performing post-exposure baking processing on the substrate is provided at the second stage position. In this case, the upper side of the post-exposure bake plate portion PEB is empty.
A heat treatment unit, a cooling treatment unit, or another heat treatment unit can be incorporated according to the use and purpose.

The transfer robot T provided between the liquid processing section and the heat treatment section at the center of the unit arrangement section MP.
A predetermined process can be performed on the substrate by sequentially transporting R1.

The interface IF has a function of temporarily stocking a substrate on which resist application has been completed in the unit arrangement section MP so as to transfer the substrate to the exposure apparatus or to receive an exposed substrate from the exposure apparatus. Although not shown, the robot includes a robot that transfers a substrate to and from the transfer robot TR1, and a buffer cassette that places the substrate. Further, the indexer ID includes a mounting portion for mounting a cassette capable of accommodating a plurality of substrates, and a transfer robot (not shown) for transferring substrates between the cassette and the transport robot TR1. And a function of paying out unprocessed substrates from the cassette to the transfer robot TR1, and receiving processed substrates from the transfer robot TR1 and storing the processed substrates in the cassette.

Table 1 shows an example of substrate processing in this substrate processing apparatus.

[0028]

[Table 1]

According to this processing sequence, the unprocessed substrate is paid out from the indexer ID, and after the adhesion strengthening processing, the cooling processing, and the resist coating processing are performed, the heat processing section HP
Prebaking is performed in 2 (processing procedure). afterwards,
After the cooling process, it is transferred to the exposure apparatus via the interface IF and is subjected to the exposure process (processing procedure). And
The exposed substrate is returned to the unit arrangement section MP via the interface IF, and the post-exposure bake plate section PEB
After baking after exposure (processing procedure), a cooling process and a developing process are performed, and the substrate is returned to the indexer ID again as a processed substrate. That is, in the present embodiment, the heat treatment section HP2 corresponds to a pre-exposure bake section, and the post-exposure bake plate section PEB corresponds to a post-exposure bake section.

<3. Configuration and Operation of Pre-Exposure Bake Unit and Post-Exposure Bake Unit> Next, the respective configurations and operations of the heat treatment unit HP2 as the pre-exposure bake unit and the post-exposure bake plate unit PEB as the post-exposure bake unit will be described. FIG. 3 is a schematic configuration diagram illustrating the heat processing unit HP2, and FIG. 4 is a schematic configuration diagram illustrating the post-exposure bake plate unit PEB.

The heat treatment section HP2 shown in FIG. 3 includes a hot plate 50 on which the substrate W is placed directly or at an appropriate interval, and a bake cover 52 above the hot plate 50 so as to cover the hot plate 50. The heat treatment space is formed between the bake cover 52 and the hot plate 50. Further, the inside of the bake cover 52 is partitioned to form a gas distribution chamber, which distributes an inert gas (nitrogen gas in the present embodiment) supplied from a gas supply source (not shown), and The inert gas can be uniformly supplied to the entire surface of the substrate W placed on the hot plate 50 from a plurality of gas outlets (supply ports) 52a provided on the bottom surface. That is,
During the heat treatment of the substrate W, the gas blowing holes 52a supply an inert gas stream from above the substrate W. The bake cover 52 is vertically movable by a support mechanism (not shown), and has a structure capable of moving up and down between a heat treatment position (the position in FIG. 3) covering the hot plate 50 and a retreat position above the heat treatment position. ing.

Hot plate 50 and bake cover 5
2 is surrounded by a chamber 54. Exhaust ports 51 a and 51 b for exhausting the gas flow of the inert gas supplied to the substrate W from the gas blowing holes 52 a are provided at both ends in the radial direction of the substrate W mounted on the hot plate 50. I have. Exhaust ports 51a, 51b
Is connected to the three-way valve 59 via the exhaust pipes 53a and 53b, respectively.
It is connected to the. Further, the three-way valve 59 is connected to an exhaust suction source (not shown) and the control unit CT of the substrate processing apparatus.
Is electrically connected to each other, and switches between communication between the exhaust suction source and the exhaust port 51a and communication between the exhaust suction source and the exhaust port 51b based on an instruction from the control unit CT. That is, the airflow supplied to the substrate W from the gas outlet 52a is switched between the exhaust from the exhaust port 51a and the exhaust from the exhaust port 51b according to an instruction from the control unit CT. When the exhaust port 51a is in communication with the exhaust suction source, the exhaust port 51b and the exhaust suction source are shut off, and no airflow is exhausted from the exhaust port 51b. The same applies to.

The post-exposure bake plate portion PEB shown in FIG.
Is the same as that of the above-mentioned heat treatment section HP2. That is, the bake cover 72 is arranged so as to cover the hot plate 70, and the plurality of gas outlets 72 a provided on the bottom surface of the bake cover 72 supply an inert gas flow from above the substrate W. The hot plate 70 and the bake cover 72 are surrounded by a chamber 74, and exhaust ports 71 a and 71 b for exhausting an air flow of the inert gas supplied to the substrate W from the gas outlets 72 a are placed on the hot plate 70. They are provided on both ends in the radial direction of the substrate W, respectively. Also, the exhaust ports 71a, 7
1b is connected to a three-way valve 79 via exhaust pipes 73a and 73b, respectively. The three-way valve 79 is connected to an exhaust suction source (not shown) and is electrically connected to the control unit CT of the substrate processing apparatus. Then, similarly to the above, the air flow supplied to the substrate W from the gas outlet 72a is controlled by the control unit CT.
Is switched between the exhaust from the exhaust port 71a and the exhaust from the exhaust port 71b.

The processing procedure in the substrate processing apparatus is shown in Table 1 above.
The substrate W is carried into each of the heat treatment section HP2 and the post-exposure bake plate section PEB during the processing. At this time, the transport robot TR1
Are the heat treatment section HP2 and the post-exposure bake plate section P
Carry-in is performed so that the substrates W are oriented in the same direction in each of the EBs. Note that the direction and orientation of the substrate W are the orientation flat or notch provided on the substrate W (not shown).
May be detected optically. For example,
In the case where the notch of the substrate W is on the right side in the drawing in the heat processing section HP2 in FIG. 3, the post-exposure bake plate section PE in FIG.
Also in B, the notch of the substrate W is on the right side in the figure.

When the exhaust from the exhaust port 51a is performed during the heat processing in the heat processing section HP2, the exhaust is performed from the exhaust port 71b during the heat processing in the post-exposure bake plate section PEB. As described above, the control unit CT controls the three-way valves 59 and 79, respectively (the state of FIGS. 3 and 4). At this time, the exhaust port 51
Of course, the exhaust from b and the exhaust port 71a is not performed.
Therefore, in the heat treatment section HP2, the gas blowing holes 52a
The airflow supplied to the substrate W from the substrate flows toward the exhaust port 51a (to the right in the figure; see FIG. 3). In the post-exposure bake plate portion PEB, the airflow supplied to the substrate W from the gas outlet 72a is exhausted. It flows toward the mouth 71b (leftward in the figure; see FIG. 4).

Conversely, when the exhaust from the exhaust port 51b is performed during the heat treatment in the heat treatment section HP2,
During the heating process in the post-exposure bake plate portion PEB, exhaust is performed from the exhaust port 71a. Therefore, in the heat treatment section HP2, the airflow supplied to the substrate W from the gas outlet 52a flows toward the exhaust port 51b (to the left in the drawing), and in the post-exposure bake plate part PEB, the gas flows from the gas outlet 72a to the substrate W. Is supplied to the exhaust port 71.
It flows toward a (rightward in the figure).

In this way, the direction of the air flow on the substrate W during the heat processing in the heat processing section HP2 and the direction of the air flow on the substrate W during the heat processing in the post-exposure bake plate section PEB are changed. The direction is reversed. In other words, the direction of the airflow on the substrate W in the pre-bake is opposite to the direction of the airflow on the substrate W in the post-exposure bake, whereby the line in the resist film of the substrate W after the development processing is formed. The width uniformity is improved.

<4. Modifications> While the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described examples. For example, in the above embodiment, in the heat treatment section HP2 and the post-exposure bake plate section PEB,
An airflow of an inert gas is supplied from above the substrate W, and an airflow is formed by exhausting the airflow from one end of the side. However, the airflow is supplied from one end of the side of the substrate W. Alternatively, the airflow may be exhausted from the other end. Specifically, in the heat treatment section HP2 in FIG. 3, the exhaust port 51b communicates with the gas supply source, and the exhaust port 51b is used as a gas supply port to form an airflow from the exhaust port 51b toward the exhaust port 51a. To do. At the same time, FIG.
In the post-exposure bake plate portion PEB, the exhaust port 7
The gas supply source 1a is communicated with the gas supply source, and an air flow is formed from the exhaust port 71a to the exhaust port 71b using the exhaust port 71a as a gas supply port. Even in this case, similarly to the above, the direction of the airflow on the substrate W in the pre-bake is opposite to the direction of the airflow on the substrate W in the post-exposure bake, and as a result, The line width uniformity of the resist film on the substrate W is improved. In the heat treatment section HP2, an airflow is formed from the exhaust port 51a to the exhaust port 51b, and an airflow is formed in the post-exposure bake plate section PEB from the exhaust port 71b to the exhaust port 71a. Needless to say, it may be done.

That is, it is only necessary that the airflow on the substrate W in the pre-bake and the airflow on the substrate W in the post-exposure bake have opposite directions.

[0040]

As described above, according to the first, second and third aspects of the present invention, the direction of the air flow on the substrate during the pre-exposure heating process and the post-exposure heating process Since the direction of the flow of the airflow on the substrate is reversed, the temperature gradients in the substrate surface between the pre-exposure bake and the post-exposure bake are opposite to each other, and after the development process. The line width uniformity in the resist film can be improved.

According to the fourth aspect of the present invention, a pre-exposure heating step of performing a pre-exposure heat treatment while flowing an air current in a first direction on the substrate after resist application and before exposure, A post-exposure heating step of performing a post-exposure heating process while flowing an airflow in a second direction opposite to the first direction on the substrate. The temperature gradient in the substrate surface is reversed between the heating step and the heating step, so that the line width uniformity of the resist film after the development processing can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a substrate processing apparatus according to the present invention.

FIG. 2 is a diagram illustrating an arrangement configuration of a processing unit in the substrate processing apparatus of FIG.

FIG. 3 is a schematic configuration diagram illustrating a heat treatment unit that is a pre-exposure bake unit.

FIG. 4 is a schematic configuration diagram showing a post-exposure bake plate section which is a post-exposure bake section.

[Explanation of symbols]

 50, 70 Hot plate 52, 72 Bake cover 51a, 51b, 71a, 71b Exhaust port 52a, 72a Gas outlet 59 Three-way valve CT control unit HP2 Heat treatment unit PEB Bake plate unit after exposure W substrate

Claims (4)

[Claims] 1. A substrate processing apparatus comprising: a pre-exposure bake unit for performing a pre-exposure bake process on a substrate before resist exposure and before exposure; and a post-exposure bake unit for performing a post-exposure bake process on the substrate before and after development. Wherein the direction of airflow on the substrate during the pre-exposure bake and the direction of airflow on the substrate during the post-exposure bake are reversed. apparatus. 2. The substrate processing apparatus according to claim 1, wherein each of the pre-exposure bake section and the post-exposure bake section includes a supply port for supplying an airflow from above the substrate being heated, and a side of the substrate. An exhaust port provided on each of one side and the other side for exhausting the supplied airflow; and a switchable switch between exhaust from the one side exhaust port and exhaust from the other side exhaust port. Means, during the pre-exposure bake section, exhausting from the one exhaust port of the pre-exposure bake section, and during the post-exposure bake section, exhausting the other side of the post-exposure bake section. A substrate processing apparatus for exhausting air from a mouth. 3. The pre-exposure bake unit according to claim 1, wherein the pre-exposure bake unit comprises: a pre-exposure supply port for supplying an airflow to the substrate from one side of a substrate being heated; A pre-exposure exhaust port for exhausting the air flow from the other side of the substrate, wherein the post-exposure bake unit supplies an air flow to the substrate from the other side of the substrate during the heat treatment. A substrate processing apparatus comprising: a rear supply port; and a post-exposure discharge port configured to discharge the supplied airflow from the one side of the substrate. 4. A substrate processing method for performing a predetermined processing including a heat treatment on a substrate, the method comprising: (a) applying a pre-exposure heating while flowing an airflow in a first direction on a substrate after resist application and before exposure; A pre-exposure heating step of performing a treatment, and (b) a post-exposure bake process in which a post-exposure bake is performed while flowing an airflow over the substrate before the exposure and development in a second direction opposite to the first direction. A substrate processing method, comprising: a heating step.