JP2021124634A5 - - Google Patents

Description

The present invention relates to an exposure apparatus and an article manufacturing method.

Conventionally, it is known that an optical element provided in a lens barrel in an exposure apparatus generates heat when irradiated with light, and the refractive index of the gas in the lens barrel changes due to the temperature, resulting in deterioration of imaging performance. .
Therefore, the optical element and its surrounding gas are cooled by supplying a temperature control gas into the lens barrel of the exposure apparatus.

On the other hand, if a temperature control gas is supplied during exposure in the optical path space of the projection optical system in the lens barrel provided in the exposure apparatus, fluctuations will occur around the projection optical system due to the difference in gas flow velocity, and the projection optical system Imaging performance may be degraded due to the vibration of the optical elements that make up the system.
Japanese Patent Application Laid-Open No. 2004-200002 discloses an exposure apparatus that does not supply a temperature control gas to a projection optical system in a lens barrel during exposure, but only during non-exposure, in order to suppress deterioration of imaging performance.

Japanese Patent Application Laid-Open No. 2008-292761

However, as in the exposure apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200010, if the supply of the temperature control gas to the inside of the lens barrel is stopped during exposure, the positive pressure inside the lens barrel cannot be maintained. Therefore, gas entering from the outside may cause chemical contamination in the optical elements provided in the lens barrel.
In addition, when the supply of the temperature control gas to the lens barrel is stopped during exposure, the refractive index changes as the temperature and pressure of the gas in the lens barrel fluctuate as described above, and the imaging performance deteriorates. will decline.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an exposure apparatus capable of suppressing deterioration of imaging performance while reducing the influence of heat due to exposure.

An exposure apparatus according to the present invention is an exposure apparatus that projects a pattern image of an original onto a substrate and exposes the substrate, and includes a projection optical system that projects the pattern image onto the substrate, and a lens barrel that accommodates the projection optical system . and a traveling direction setting means for setting the traveling direction of the gas supplied from the gas supply means into the lens barrel, and setting the traveling direction so that the traveling direction differs between the time of exposure for exposing the substrate and the time of non-exposure. and a control unit for controlling the means.

According to the present invention, it is possible to provide an exposure apparatus capable of suppressing deterioration of imaging performance while reducing the influence of heat due to exposure.

4A and 4B are schematic cross-sectional views of the exposure apparatus according to the first embodiment at the time of non-exposure and exposure. 4 is a flowchart showing louver switching control in the exposure apparatus according to the first embodiment. FIG. 6 is a schematic cross-sectional view of the exposure apparatus according to the second embodiment during exposure. FIG. 6 is a schematic cross-sectional view of the exposure apparatus according to the third embodiment during exposure. FIG. 11 is a schematic cross-sectional view of an exposure apparatus according to a fourth embodiment during exposure; FIG. 11 is a schematic cross-sectional view of an exposure apparatus according to a fifth embodiment during exposure;

An exposure apparatus according to this embodiment will be described in detail below with reference to the accompanying drawings. It should be noted that the drawings shown below are drawn on a scale different from the actual scale in order to facilitate understanding of the present embodiment.
In the following description, the direction perpendicular to the photosensitive surface of the plate 4 is the Z direction, and the two directions perpendicular to each other within the photosensitive surface of the plate 4 are the X direction and the Y direction.

[First embodiment]
FIGS. 1A and 1B are schematic cross-sectional views of an exposure apparatus 100 including an optical device according to the first embodiment during non-exposure and exposure, respectively.

An exposure apparatus 100 having an optical device according to this embodiment includes an illumination system 1, an alignment scope 2, a projection optical system 5 (optical element), a lens barrel 11, a controller 18, and a pressure sensor 19.
The projection optical system 5 includes a reflecting mirror 7, a concave mirror 8, and a convex mirror 9, as shown in FIGS. 1(a) and 1(b).

Further, as shown in FIGS. 1(a) and 1(b), the lens barrel 11 is provided with an exhaust port 14, an air supply port 15, and a louver 16 (advancing direction setting means, variable louver). .
The optical apparatus according to this embodiment comprises a projection optical system 5 , a lens barrel 11 , a louver 16 , a controller 18 and a pressure sensor 19 .

In the exposure apparatus 100, the illumination light 12 (exposure light) from the illumination system 1 passes through the mask 3 (original), and then is irradiated onto the plate 4 (substrate) via the projection optical system 5. An image of the drawn pattern is projected (transferred) onto the photosensitive member on the plate 4 .
In the exposure apparatus 100, a mask stage (not shown) on which the mask 3 is placed and a plate stage (not shown) on which the plate 4 is placed are scanned in synchronization with each other along the Y direction.
In general, the lens barrel 11 and each component of the exposure apparatus 100 are installed in a temperature control chamber (not shown) in order to guarantee their performance.

The air supply port 15 communicates with gas supply means (not shown), and a gas 17 (hereinafter referred to as temperature-controlled gas) that is temperature-controlled into the lens barrel 11 from the gas supply means through the air supply port 15 . is supplied.
Then, the traveling direction of the temperature control gas 17 supplied from the air supply port 15 is set by the louver 16 .

For example, when a liquid crystal panel or the like is manufactured by photolithography using a mirror projection type exposure apparatus such as the exposure apparatus 100, it may be necessary to improve definition.
In that case, in order to increase the irradiation amount of the exposure light 12 onto the photosensitive member on the plate 4, the illuminance of the illumination system 1 is increased and the scanning speed of the plate stage (not shown) on which the plate 4 is placed is decreased. can be considered.
Here, when the energy per unit time irradiated to the photoreceptor on the plate 4 is the amount of exposure (DOSE), such an exposure process is called a high DOSE exposure process (high load exposure process, high energy incident process). can call

When such a high DOSE exposure process is performed, the temperature inside the lens barrel 11 becomes higher than in the normal DOSE exposure process.
This is because the energy of the exposure light 12 incident on the optical elements included in the projection optical system 5 increases, and the optical elements generate a large amount of heat, thereby warming the gas around the optical elements.

Since the gas warmed by the heat generated by the optical element moves upward in the Z direction, the temperature of the gas upward in the Z direction inside the lens barrel 11 becomes higher than that in the downward direction.
As a result, the refractive index of the gas above in the Z direction where the temperature rises changes, so if the exposure process is performed in such a state, there is a risk that the imaging performance will deteriorate compared to the normal DOSE exposure process.

In particular, the projection optical system 5 provided in the mirror projection type exposure apparatus as in this embodiment extends in a direction intersecting the vertical direction (Z direction) parallel to the incident and outgoing directions of the exposure light 12. It has a concave mirror 8 and a convex mirror 9 having optical axes that correspond to each other.
As a result, the above-described temperature difference occurs between the gases surrounding the concave mirror 8 and the convex mirror 9 in the vertical direction, respectively, and the deterioration of the imaging performance according to the image height becomes significant.

Therefore, in order to suppress the deterioration of imaging performance by reducing such a temperature difference in the lens barrel of the exposure apparatus, a temperature control gas is supplied to the lens barrel to cool the optical elements inside the lens barrel. is being done.

On the other hand, when the temperature control gas is supplied to the optical path (optical path space) of the exposure light 12 in the lens barrel 11 , fluctuations occur due to the difference in flow velocity between the gases around the concave mirror 8 and the convex mirror 9 . and the convex mirror 9 may vibrate, the imaging performance may be degraded.
Therefore, there is known a method of suppressing deterioration in imaging performance by temporarily stopping the supply of the temperature control gas during exposure or alignment.

However, if the supply of the temperature control gas is temporarily stopped, the positive pressure inside the lens barrel 11 is not maintained, and there is a risk that the gas entering from the outside may cause chemical contamination in the optical elements inside the lens barrel 11 .
Further, the refractive index changes as the temperature and pressure of the gas in the lens barrel 11 fluctuate, resulting in unstable imaging performance.

Therefore, in the exposure apparatus 100 including the optical device according to the present embodiment, the problems described above can be solved by performing the control described below.

FIG. 2 is a flowchart showing switching control of the louver 16 in the exposure apparatus 100 having the optical device according to this embodiment. Note that the control described below is performed by the control unit 18 .

First, it is determined whether or not an exposure processing command has been issued in the exposure apparatus 100 (step S1). If an exposure processing command has not been issued, that is, if the exposure apparatus 100 is in the non-exposure state (No in step S1), the louver 16 is adjusted so that the temperature control gas is supplied into the optical path space of the lens barrel 11. direction is set (step S2). In other words, in step S2, the traveling direction of the temperature control gas is set (changed) so that the temperature control gas is supplied into the optical path space of the lens barrel 11 by the louver 16 . After that, the process returns to step S1.

On the other hand, when an exposure process command is issued, that is, when the exposure apparatus 100 performs the exposure process (Yes in step S1), the louver 16 is adjusted so that the temperature control gas is supplied outside the optical path space of the lens barrel 11. A direction is set (step S3). In other words, in step S3, the traveling direction of the temperature control gas is set (changed) so that the temperature control gas is supplied to the outside of the optical path space of the lens barrel 11 by the louver 16 . After that, exposure is started (step S4).
Then, when the exposure ends, that is, when the exposure apparatus 100 becomes non-exposure (step S5), the direction of the louver 16 is set so that the temperature control gas is supplied into the optical path space of the lens barrel 11 (step S6), Return to step S1.

As described above, in the exposure apparatus 100, the traveling direction of the temperature-controlled gas is set so that the temperature-controlled gas does not pass through the optical path of the projection optical system 5 during exposure. The traveling direction of the temperature control gas is set so as to pass through the optical path of the projection optical system 5 .

In the above control, after the direction of the louver 16 is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 in step S3, the pressure in the lens barrel 11 is stabilized, and then the step Exposure is preferably started in S4.
Therefore, the exposure apparatus 100 including the optical device according to this embodiment is provided with a pressure sensor 19 for monitoring the pressure inside the lens barrel 11 .

Further, in the exposure apparatus 100 including the optical device according to the present embodiment, it is preferable that the switching (setting) of the direction of the louver 16 in step S3 be timing-controlled so as to be performed especially when the plate 4 is replaced.
It should be noted that the orientation of the louver 16 may be switched between lots when waiting for the exposure operation between lots when processing plates 4 of a plurality of lots.
Further, it is preferable not to switch the direction of the louver 16 when the plate 4 is being aligned, that is, when the alignment light is passing through the optical path of the projection optical system 5 .

Further, in the exposure apparatus 100, the internal space of the lens barrel 11 has a weak positive pressure in order to suppress the intake of air from the outside.
On the other hand, when the supply of the temperature control gas to the lens barrel 11 is stopped as in the conventional exposure apparatus, the pressure in the internal space of the lens barrel 11 changes to atmospheric pressure.

Here, n1 is the refractive index of the gas in the lens barrel 11 when the temperature control gas is being supplied into the lens barrel 11, that is, the refractive index of the gas at atmospheric pressure + about ₁ Pa. Let _n0 be the refractive index of the gas in the lens barrel 11 when the supply of the temperature control gas to the lens barrel 11 is stopped, that is, the refractive index of the gas at atmospheric pressure.
At this time, the change Δn in the refractive index of the gas caused by stopping the supply of the temperature control gas into the lens barrel 11 can be obtained from the following equation (1).
Δn=n ₁ −n ₀ (1)

If air is used as the temperature control gas supplied into the lens barrel 11, the refractive indices _n0 and n1 can be calculated from Edren's formula shown in the following formula ( ₂ ).

Here, the pressure P1 in the lens barrel 11 when air is being supplied to the lens barrel 11 is ₁₀₁₃₀₉ Pa, and the pressure P1 in the lens barrel 11 when the air supply to the lens barrel 11 is stopped is Let ₀ be 101308 Pa.
Assuming that the temperature T and humidity H remain unchanged at 23 degrees and 50%, respectively, the change Δn in the refractive index can be obtained as 2.66×10 ⁻⁹ from equation (2).
This refractive index change affects the imaging performance. Specifically, the change in the refractive index causes shifts in focus and distortion in proportion to the length of the optical path, and these shifts widen the line width of the pattern transferred from the mask 3 to the plate 4. lead to poor performance.

In addition, when the temperature control gas is supplied to the optical path space in the lens barrel 11 during exposure, fluctuations occur due to the difference in flow velocity between the gases around the optical element, and the optical element vibrates, resulting in overlay ( There is a possibility that the superimposition accuracy will be lowered.

Therefore, the inventors of the present application compared the case where air was supplied to the optical path space in the lens barrel 11 during exposure and the case where it was not, in order to examine such a decrease in overlay accuracy.
Specifically, the measurement reproducibility in the alignment mechanism using the alignment scope 2, the mask 3 and the plate 4 was evaluated.
As a result, it was found that the measurement reproducibility in the alignment mechanism is reduced by 40% when air is supplied to the optical path space in the lens barrel 11 during exposure compared to when it is not supplied.
When the measurement reproducibility of the alignment mechanism is lowered in this way, it leads to misalignment in alignment and the like, and overlay accuracy is lowered.

As described above, in the exposure apparatus 100 including the optical device according to this embodiment, the direction of the louver 16 is set so that the temperature control gas is supplied into the optical path space of the lens barrel 11 during non-exposure. On the other hand, the direction of the louver 16 is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure.

Since the supply of the temperature control gas is not stopped, the pressure in the lens barrel 11 does not change between exposure and non-exposure, that is, the refractive index of the gas in the lens barrel 11 does not change. Therefore, in the exposure apparatus 100 including the optical device according to this embodiment, it is possible to suppress deterioration in imaging performance due to changes in the refractive index.
In addition, since the direction of the louver 16 is switched so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure, it is possible to suppress the deterioration of the overlay accuracy as described above.

In the optical device according to this embodiment, as shown in FIGS. 1A and 1B, the exhaust port 14 and the air supply port 15 are provided at four locations and one location, respectively. However, the number of exhaust ports 14 and air supply ports 15 is not limited to this.
Further, in the optical device according to the present embodiment, the gas supplied to the lens barrel 11 and the gas discharged from the lens barrel 11 are air, but the present invention is not limited to this. For example, other gas such as an inert gas may be used as long as it can control the temperature inside the lens barrel 11 without adversely affecting the projection optical system 5 inside the lens barrel 11 .

[Second embodiment]
FIG. 3 shows a schematic cross-sectional view during exposure of an exposure apparatus 200 including an optical device according to the second embodiment.
The optical device according to the present embodiment has the same configuration as the optical device according to the first embodiment, except that a non-exposure supply port 20a and an exposure supply port 20b are provided instead of the louver 16. Therefore, the same members are given the same numbering, and the description thereof is omitted.

As shown in FIG. 3, in the exposure apparatus 200 including the optical device according to the present embodiment, the supply opening during exposure is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure. A temperature control gas is supplied into the lens barrel 11 from 20b (gas supply port).
On the other hand, the temperature control gas is supplied into the lens barrel 11 from the non-exposure supply port 20a (gas supply port) so that the temperature control gas is supplied into the optical path space of the lens barrel 11 during non-exposure.

As a result, the pressure in the lens barrel 11 does not change between the time of exposure and the time of non-exposure, that is, the refractive index of the gas in the lens barrel 11 does not change. be able to.
In addition, since the temperature control gas is supplied into the lens barrel 11 from the exposure supply port 20b so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure, deterioration in overlay accuracy is also suppressed. can do.

[Third embodiment]
FIG. 4 shows a schematic cross-sectional view of an exposure apparatus 300 including an optical device according to the third embodiment during exposure.
Note that the optical device according to the present embodiment has the same configuration as the optical device according to the first embodiment except that the aero parts 21 are newly provided, so the same members are assigned the same numbers. description is omitted.

As shown in FIG. 4, in the exposure apparatus 300 including the optical device according to the present embodiment, the direction of the louver 16 is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure. It is Aero parts 21 are provided so that the temperature control gas that has passed through the louvers 16 is directed to a predetermined exhaust port 14 during exposure. In other words, in the exposure apparatus 300 including the optical device according to this embodiment, the aeropart 21 restricts the traveling path of the temperature control gas inside the lens barrel 11 .
Thereby, the directivity of the temperature control gas to the predetermined exhaust port 14 can be further enhanced. The length of the aero parts 21 in the X direction is substantially the same as the width of the internal space of the lens barrel 11 in the X direction.

Then, similarly to the optical apparatus according to the first embodiment, the direction of the louver 16 is set so that the temperature control gas is supplied into the optical path space of the lens barrel 11 during non-exposure. On the other hand, the orientation of the louver 16 is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure.
As a result, the pressure in the lens barrel 11 does not change between the time of exposure and the time of non-exposure, that is, the refractive index of the gas in the lens barrel 11 does not change. be able to.
In addition, since the direction of the louver 16 is switched so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure, it is possible to suppress the deterioration of the overlay accuracy as described above.

[Fourth embodiment]
FIG. 5 shows a schematic cross-sectional view during exposure of an exposure apparatus 400 including an optical device according to the fourth embodiment.
The optical device according to this embodiment has the same configuration as the optical device according to the first embodiment, except that the movable aero parts 22 are provided instead of the louvers 16. are numbered and the description is omitted.

As shown in FIG. 5, in the exposure apparatus 400 including the optical device according to the present embodiment, the movable aeroparts 22 are arranged so that the center of the movable aeroparts 22 in the YZ cross section is placed at the position P1 during exposure. Move 22. As a result, the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure.
On the other hand, during non-exposure, the movable aero parts 22 are moved so that the center of the movable aero parts 22 in the YZ cross section is arranged at the position P2. As a result, the temperature control gas is supplied into the optical path space of the lens barrel 11 during non-exposure.
The length of the movable aero parts 22 in the X direction is substantially the same as the width of the internal space of the lens barrel 11 in the X direction.

As a result, the pressure in the lens barrel 11 does not change between the time of exposure and the time of non-exposure, that is, the refractive index of the gas in the lens barrel 11 does not change. be able to.
In addition, since the movable aero parts 22 are moved so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure, deterioration of overlay accuracy can be suppressed.

In the optical device according to the present embodiment, the movable aeroparts 22 are moved between exposure and non-exposure, but the size and shape of the movable aeroparts 22 may be changed. .

[Fifth embodiment]
FIG. 6 shows a schematic cross-sectional view during exposure of an exposure apparatus 500 including an optical device according to the fifth embodiment.
Note that the optical device according to the present embodiment has the same configuration as the optical device according to the first embodiment, except that the light amount detection sensor 24 is newly provided. , and the description is omitted.

As shown in FIG. 6, an exposure apparatus 500 having an optical device according to this embodiment has a light amount detection sensor 24 on the optical path of the projection optical system 5 in the lens barrel 11 . This makes it possible to detect whether or not the alignment light is passing through the optical path of the projection optical system 5 particularly in the alignment process for the plate 4 .
As mentioned above, it is preferable not to change the orientation of the louvers 16 when aligning the plate 4 .
Therefore, when alignment is not performed in the exposure apparatus 500 , that is, when alignment light does not pass through the optical path of the projection optical system 5 based on the detection result of the light amount detection sensor 24 , the temperature control gas does not enter the optical path space of the lens barrel 11 . Orient the louver 16 so that it feeds inside. On the other hand, the orientation of the louver 16 is set so that the temperature control gas is supplied to the outside of the optical path space of the lens barrel 11 during non-exposure, specifically immediately before the start of exposure.

As a result, the pressure in the lens barrel 11 does not change between the time of exposure and the time of non-exposure, that is, the refractive index of the gas in the lens barrel 11 does not change. be able to.
In addition, since the direction of the louver 16 is set so that the temperature control gas is supplied outside the optical path space of the lens barrel 11 during exposure, it is possible to suppress the deterioration of the overlay accuracy as described above.

Although the optical device according to the present embodiment is provided with the light amount detection sensor 24, the present invention is not limited to this, and a heat amount detection sensor may be provided.

Although preferred embodiments have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

[Product manufacturing method]
Next, an article manufacturing method using an exposure apparatus having an optical device according to any one of the first to fifth embodiments will be described.

Articles are semiconductor devices, display devices, color filters, optical components, MEMS, and the like.
For example, a semiconductor device is manufactured through a pre-process for forming a circuit pattern on a wafer and a post-process including a processing process for completing the circuit chip formed in the pre-process as a product.
The pre-process includes an exposure step of exposing a wafer coated with a photosensitive agent using an exposure apparatus equipped with the optical device according to any one of the first to fifth embodiments, and a developing step of developing the photosensitive agent. .

An etching process, an ion implantation process, and the like are performed using the developed pattern of the photosensitive agent as a mask to form a circuit pattern on the wafer.
By repeating these steps of exposure, development, etching, etc., a circuit pattern consisting of a plurality of layers is formed on the wafer.
In a post-process, the wafer on which the circuit pattern is formed is diced, and chip mounting, bonding, and inspection processes are performed.

A display device is manufactured through a process of forming a transparent electrode. The step of forming the transparent electrode includes the step of applying a photosensitive agent to the glass wafer on which the transparent conductive film is deposited, and applying the photosensitive agent using an exposure apparatus equipped with the optical device according to any one of the first to fifth embodiments. exposing a glass wafer coated with Also, the step of forming the transparent electrode includes the step of developing the exposed photosensitive agent.

According to the method for manufacturing an article according to the present embodiment, it is possible to manufacture articles of higher quality and higher productivity than conventional ones.

5 projection optical system
11 lens barrel 16 louver (moving direction setting means)
18 control unit

Claims (12)

An exposure apparatus that projects a pattern image of an original onto a substrate and exposes the substrate,
a projection optical system that projects an image of the pattern onto the substrate ;
a barrel housing the projection optical system ;
traveling direction setting means for setting the traveling direction of the gas supplied from the gas supply means into the lens barrel;
a control unit for controlling the traveling direction setting means such that the traveling direction is different between when the substrate is exposed to light and when the substrate is not exposed ;
An exposure apparatus comprising: 2. An exposure apparatus according to claim 1, wherein said advancing direction setting means is a variable louver provided on said lens barrel. 2. An exposure apparatus according to claim 1, wherein said traveling direction setting means is a plurality of gas supply ports provided in said lens barrel. 4. An exposure apparatus according to any one of claims 1 to 3, wherein said lens barrel is provided with an aeropart for restricting a traveling path of gas in said lens barrel. 2. An exposure apparatus according to claim 1, wherein said traveling direction setting means is a movable aeropart provided on said lens barrel. The control unit controls the advancing direction setting unit so that the supplied gas does not pass through the optical path of the projection optical system during exposure, while the supplied gas is controlled by the gas during non-exposure. 6. An exposure apparatus according to any one of claims 1 to 5 , wherein said traveling direction setting means is controlled so as to pass through an optical path of a projection optical system. 7. An exposure apparatus according to claim 6 , wherein said control section controls said traveling direction setting means such that said traveling direction is changed during said non-exposure. 8. The method according to claim 7 , wherein the control section controls the traveling direction setting means so that the traveling direction is changed when the alignment light is not passing through the optical path of the projection optical system. exposure equipment. 9. An exposure apparatus according to claim 7 , wherein said controller controls said traveling direction setting means such that said traveling direction is changed when said substrate is replaced. a light amount detection sensor that detects the amount of light on the optical path of the projection optical system;
10. The exposure apparatus according to any one of claims 1 to 9 , wherein the control unit determines whether alignment of the substrate is performed based on a detection result of the light amount detection sensor. A pressure sensor that detects the pressure in the lens barrel,
11. The exposure apparatus according to any one of claims 1 to 10 , wherein exposure is performed after it is determined that the pressure has stabilized from the detection result of the pressure sensor. exposing the substrate using the exposure apparatus according to any one of claims 1 to 11 ;
developing the exposed substrate;
a step of processing the developed substrate to obtain an article;
A method for manufacturing an article, comprising: