JP2003059802A - Aligner and method for controlling the same, and method for manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten substitution time of gas in a space (a light path space), where an exposure light passes such as the space between a projection light system and a substrate, with an inert gas. SOLUTION: The aligner comprises a wafer stage 102, a projection optical system 101, a gas feed section 112 for feeding an inert gas in a light path space 116 where exposure light passes between the wafer stage 102 and the projection light system 101, a stage controller 132 controls the movement of the wafer stage 102, when it moves under the light path space 116 based on the concentration or pressure of the prescribed gas in the light path space 116.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for manufacturing, for example, semiconductor devices, image pickup devices, liquid crystal display devices, thin film magnetic heads and other microdevices.

[0002]

2. Description of the Related Art In a photolithography process for manufacturing a semiconductor device or the like, an exposure apparatus is used which projects a pattern image of a mask (for example, a reticle) onto a photosensitive substrate through a projection optical system to expose it. In recent years, semiconductor integrated circuits have been developed in the direction of miniaturization, and in the photolithography process, the wavelength of the photolithography light source has been shortened.

However, vacuum ultraviolet rays, especially 250n
Light having a wavelength shorter than m, for example, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 19
3 nm), F ₂ laser (wavelength 157 nm), or YA
When light such as a harmonic of G laser is used as the exposure light, or when X-rays are used as the exposure light, the intensity of the exposure light is reduced due to the influence of the absorption of the exposure light by oxygen or the like. Was occurring.

Therefore, conventionally, in an exposure apparatus having a light source such as an F ₂ excimer laser, a sealed space for sealing only the optical path portion is formed, and for example, a gas containing no oxygen such as nitrogen is used to seal the sealed space. The gas was replaced to try to avoid a decrease in the transmittance of the exposure light.

FIG. 20 shows that an inert gas atmosphere is formed in the space between the final optical member of the projection optical system (lens barrel) and the photosensitive substrate (wafer) by supplying the inert gas. It is a figure which shows the exposure apparatus which implements exposure. In this exposure apparatus, a shielding member is provided around the space for separating the space above the exposure region and the atmosphere around the space, and an inert gas is supplied into the space from the periphery of the exposure region.

[0006]

However, as shown in FIG.
In the exposure apparatus shown in (1), it takes about several seconds until the oxygen concentration in the space above the exposure area decreases after the wafer enters the exposure area due to the driving of the wafer stage, which causes a decrease in throughput. Was there.

The same problem applies to the case where an inert gas is supplied around the reticle, and it takes about several seconds for the oxygen concentration in the space surrounded by the shielding member to decrease in the reticle as well. This has been the cause of the decrease in throughput.

The present invention has been made in view of the above problems, and holds, for example, a space between a projection optical system and a substrate, an illumination optical system for illuminating a mask (for example, a reticle), and the mask. Required to replace the gas in the optical path space including the space (exposure region) through which the exposure light passes, such as the space between the mask stage and the space between the mask stage and the projection optical system, with an inert gas. An object of the present invention is to provide an exposure apparatus, a control method therefor, and a device manufacturing method capable of shortening the time.

[0009]

An exposure apparatus according to the present invention for achieving the above object has the following configuration. That is, it is an exposure apparatus that projects and transfers a pattern formed on a mask onto a substrate using exposure light, in which a stage, an optical system, and a space between the stage and the optical system where the exposure light passes. A stage for moving the stage below the optical path space based on either a gas flow forming mechanism that forms a flow of an inert gas in the optical path space including the concentration of a predetermined gas inside the optical path space or the pressure inside the optical path space. And a control means for controlling the movement of the stage at the time.

Also, preferably, the control means controls the stage so that the moving speed of the stage becomes less than the maximum moving speed.

Preferably, the control means controls the stage so that the stage decelerates or temporarily stops.

Further, preferably, the control means controls the stage so as to decelerate or temporarily stop the stage before the opening area of the optical path space is minimized.

Also, preferably, the predetermined gas is any one of the above-mentioned inert gas or gas components in the atmosphere other than the above-mentioned inert gas, or a combination thereof.

Preferably, the apparatus further comprises concentration measuring means arranged in the optical path space for measuring the concentration of the predetermined gas.

Further, preferably, the control means, after a predetermined movement amount step by step movement of the stage,
After confirming that the predetermined gas has reached the predetermined concentration, the step is further moved, and by repeating this, the movement of the stage is controlled.

Further, preferably, the control means controls the movement of the stage while confirming that the predetermined concentration of the predetermined gas corresponding to the movement amount of the stage has been reached.

Preferably, the relationship between the opening area of the optical path space determined by the position of the optical path space and the stage and the concentration of the predetermined gas in the optical path space is obtained,
Based on the target concentration determined from the concentration of the predetermined gas, the movement of the stage when the stage moves under the optical path space is controlled.

Further, preferably, the target density is a value obtained by multiplying the reached density determined by the opening area by a predetermined magnification.

Further, preferably, the control means controls the movement of the stage by referring to a table stored in advance in association with the time series of the opening area and the concentration of the predetermined gas.

Further, preferably, a table stored in advance in association with the time series of the supply amount of the inert gas to the optical path space, the opening area, and the concentration of the predetermined gas is referred to, Control movement.

[0021] Further, preferably, the control means further comprises pressure measuring means arranged in the optical path space for measuring the pressure inside the optical path space, and the control means based on the measurement result of the pressure measuring means. Control the movement of.

Further, preferably, the control means controls the moving speed of the stage so that the change amount of the pressure per unit time is equal to or less than a predetermined change amount.

Further, preferably, the control means controls the movement of the stage so as to decelerate or temporarily stop the moving speed of the stage when the pressure rises above a predetermined pressure.

Further, preferably, the gas flow forming mechanism includes a supply mechanism for supplying an inert gas to the optical path space,
At least a supply mechanism is provided among exhaust mechanisms for exhausting a gas containing an inert gas from the optical path space.

Further, preferably, the supply mechanism has two gas supply portions arranged at positions opposed to each other with the optical path space interposed therebetween.

Further, preferably, a height adjusting member for smoothing a height change between the substrate stage, the substrate chuck mounted on the substrate stage, and the substrate chucked by the substrate chuck and its periphery. And are further provided.

Further, preferably, a four-sided shield member surrounding the optical path space is further provided, and the height of one side of the four-sided shield member is different from the other three sides.

Further, preferably, the gas flow forming mechanism is arranged so as to form a flow of the inert gas in the optical path space between the projection optical system and the substrate.

Further, preferably, the gas flow forming mechanism is arranged so as to form a flow of an inert gas in an optical path space between an illumination system for illuminating a mask and a mask stage for holding the mask. .

Further, preferably, the gas flow forming mechanism is arranged so as to form a flow of the inert gas in an optical path space between the mask stage holding the mask and the projection optical system.

Further, preferably, the gas flow forming mechanism is a first gas flow forming mechanism arranged to form a flow of an inert gas in a first optical path space between the projection optical system and the substrate, A second gas flow forming mechanism arranged to form a flow of an inert gas in a second optical path space between an illumination system for illuminating a mask and a mask stage for holding the mask, the mask stage and the projection A third optical path space formed between the optical system and the third optical path space so as to form a flow of the inert gas.
And a gas flow forming mechanism.

Further, preferably, the supply amount of the inert gas supplied to the optical path space by the gas flow forming mechanism is equal to or more than the exhaust amount for exhausting the gas containing the inert gas.

Also, preferably, the predetermined gas is nitrogen gas or helium gas.

An exposure apparatus control method according to the present invention for achieving the above object has the following configuration. That is, a stage, an optical system, and a gas flow forming mechanism that forms a flow of an inert gas in an optical path space including a space where the exposure light passes between the stage and the optical system are formed on a mask. A method of controlling an exposure apparatus for projecting and transferring a patterned pattern onto a substrate by using exposure light, comprising: a deriving step of deriving a concentration of a predetermined gas inside the optical path space; and a concentration based on the concentration derived by the deriving step. And a control step of controlling the movement of the stage when the stage moves under the optical path space.

A device manufacturing method according to the present invention for achieving the above object has the following configuration. That is, it is a device manufacturing method, and comprises a transfer step of transferring a pattern to a substrate coated with a photosensitive material using an exposure apparatus, and a developing step of developing the substrate, the exposure apparatus includes a stage, An optical system, a gas flow forming mechanism that forms a flow of an inert gas in an optical path space including a space through which exposure light passes between the stage and the optical system, and a concentration of a predetermined gas inside the optical path space And a control means for controlling the movement of the stage when the stage moves under the optical path space.

[0036]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
It is a figure which shows a part of exposure apparatus of this.

This exposure apparatus is provided with a light source for generating short-wavelength laser light such as an F ₂ excimer laser (not shown) as illumination light, and the illumination light (exposure light) of the light source is emitted from an appropriate illumination optical member. The reticle (mask) is evenly illuminated through. The light (exposure light) that has passed through the reticle reaches the surface of the wafer 103 mounted on the wafer stage 102 via various optical members that form the projection optical system 101, and connects the reticle pattern here. Image.

The wafer stage 102 on which the wafer 103 is placed is movable in three-dimensional directions (XYZ directions). The reticle pattern is sequentially projected and transferred onto the wafer 103 by a so-called stepping and repeat method in which stepping movement and exposure are repeated. Moreover, even when the present invention is applied to a scan exposure apparatus, the configuration is almost the same.

At the time of exposure, a temperature-controlled inert gas (for example, nitrogen gas, helium gas, etc.) is passed between the shield member 115 below the projection optical system 101 and the wafer 103 via the air supply valve 111. A space (hereinafter, referred to as an optical path space) 116 including a space through which light passes and its periphery is supplied from an air supply port 113. Part of the inert gas supplied to the optical path space 116 is recovered by the exhaust port 114 and exhausted via the exhaust valve 112. The air supply valve 111, the air supply port 113, the exhaust port 114, the exhaust valve 112, etc. are an example of a gas flow forming mechanism that forms a flow of a gas such as an inert gas in the optical path space 116. Although the exhaust port 114 is provided in this embodiment, the exhaust port 114 is not always necessary. Exhaust port 11
4 may be used as the air supply port.

The arrow in FIG. 1 indicates the flow of the inert gas. Around the wafer 103 on the wafer stage 102, a height adjusting plate 181 having substantially the same height as the wafer 103 or slightly lower (for example, about 1 mm) is provided. When exposing the periphery of the wafer 103, the optical path space 116
The presence of the wafer 103 or the height adjusting plate 181 prevents the opening area of the optical path space 116 from increasing and prevents the concentration of the atmosphere inside the optical path space 116 from being deteriorated by the atmosphere outside the optical path space 116.

Basically, the oxygen concentration in the exposure atmosphere is lowered by setting the optical path space 116 to a positive pressure with respect to the surrounding atmosphere. Therefore, the amount of the inert gas leaking from the optical path space 116 to the peripheral space is larger than the exhaust amount exhausted through the exhaust valve 112. The inert gas leaking out of the optical path space 116 is collected and exhausted by the exhaust unit 122 together with the surrounding atmosphere supplied from the air supply unit 121.

The opening / closing and opening of the air supply valve 111 and the exhaust valve 112 are controlled by the environment controller 131. Normal,
The air supply valve 111 and the exhaust valve 112 are open, and the inert gas is constantly supplied into the optical path space 116 regardless of the position of the stage 102. However, at the time of wafer replacement and maintenance, the optical path space 116
When the stage 102 comes off from below, the supply of the inert gas is temporarily stopped or the supply amount is reduced, and the supply is started before the stage 102 reenters the optical path space 116 after the wafer replacement, or the supply amount is reduced. You may perform control to return.

The oxygen concentration meter 117 for measuring the oxygen concentration in the optical path space 116 and the stage 102 are controlled by the stage controller 132. The environment controller 131, the stage controller 132, and other controllers (not shown) are collectively controlled by the main controller 133 in various operations such as wafer exchange, alignment operation, and exposure operation. The monitoring device 134 monitors the control content of the main controller 133 and the operating state of the exposure apparatus.

Even when the amount of inert gas supplied to the optical path space 116 is not reduced during wafer replacement, the oxygen concentration in the optical path space 116 becomes considerably high due to the influence of the surrounding atmosphere.
Wafer stage 10 with wafer 103 mounted in that state
When 2 enters below the optical path space 116, the exhaust efficiency of the gas in the optical path space 116 deteriorates as the opening area of the optical path space 116 decreases. Therefore, it took about several seconds until the oxygen concentration in the optical path space 116 decreased, which was a factor of reducing the throughput.

Therefore, in the first embodiment, the target oxygen concentration is set based on the relationship between the opening area of the optical path space 116 determined by the position of the wafer stage 102 and the oxygen concentration in the optical path space 116, and the opening is performed while measuring the oxygen concentration. By controlling the wafer stage 102 so as to control the area, the oxygen concentration in the optical path space 116 is rapidly reduced.

Here, the opening area will be described.

As shown in FIG. 2, there is a gap 200 below the optical path space 116 and between the wafer 103 and the wafer 103 as a flow path for the inert gas leaking from the optical path space 116. Area 201 of surface 201 of gap 200 in contact with wafer 103
S is a stage 102 (wafer 103, height adjustment plate 181
Is included in the area of the stage 102.
Changes with the movement of. The maximum value of the area 201S is when the stage 102 does not exist below the optical path space 116, and the 201S gradually decreases as the stage 102 enters the optical path space 116, and FIG. 201S, the stage 102 (including the wafer 103 and the height adjusting plate 181) finally completes plunging under the gap 200, and the 201S becomes 0.
(Hereinafter, when the area of 201S becomes 0, the rush is completed). In the present invention, the opening area is set to 201S. If there is a difference in height between the wafer 103 and the height adjusting plate 181, the gap 200 is always open 203S,
It is preferable to add the area of the surface of 204S, 205S, 206S to 201S and set it as the opening area.

Here, FIG. 4 shows the relationship between the oxygen concentration in the optical path space 116 and the opening area.

In FIG. 4, the horizontal axis represents the opening area of the optical path space 116 and the vertical axis represents the oxygen concentration in the optical path space 116. In this case, the oxygen concentration is displayed in a state where the internal concentration is stable after the stage has stopped at that coordinate with respect to the opening area. The oxygen concentration decreases as the opening area decreases.

Further, the oxygen concentration changes depending on the supply amount, and if the supply amount is large, the oxygen concentration can be reduced even if the opening area is slightly large. Further, if the supply amount is too small, the oxygen concentration cannot be reduced to the minimum value even if the opening area is minimized. Usually stage 102
The inert gas is supplied to the optical path space 116 to such an extent that the oxygen concentration does not rise in the optical path space 116 due to the entrainment of the surrounding atmosphere accompanying the movement of.

FIG. 5 shows the stage coordinates and the opening area 201S,
Also, the relationship between the oxygen concentrations in the optical path space 116 is shown.

In FIG. 5, A is a plunge start coordinate at which the height adjusting plate 181 starts plunging under the optical path space 116,
B is a plunge completion coordinate at which the wafer 103 or the height adjusting plate 181 completes plunging into the optical path space 116.

A steady density (a density in a state where the internal density is stable after the stage stops at that coordinate: a broken line) with respect to the opening area 201S and the stage is rushed under the optical path space 116 as usual (at the maximum speed of the stage). It is a graph which compared the density (solid line) at the time of making it.

It can be seen that the oxygen concentration is higher in the case of the conventional concentration, and that the gradient of decrease of the oxygen concentration becomes gentle from the vicinity of the opening area of 0 (before and after B).

This is the optical path space 116 of the stage 102.
This is because the opening area 201S is reduced due to the entry into and the exhaust efficiency is deteriorated, so that the replacement time with the inert gas is lengthened.

Further, in the conventional density change, the slope changes depending on the stage speed, and when the stage speed is slow, it becomes closer to a more steady density change.

It suffices to control the stage 102 so that the conventional density change can be approximated to a steady density change in the shortest possible time.

As can be seen from FIG. 5, there is a difference between the stationary density and the conventional density from stage coordinates C to B.

Therefore, FIG. 6 shows a graph obtained by converting the stage coordinate axes of the graph of FIG. 5 into a time axis.

FIG. 6 shows a change in the conventional opening area (solid line) when the stage speed is constant, and a change in oxygen concentration (solid line) accompanying the change in the opening area.

In FIG. 6, the decrease in the opening area is moderated from the coordinate C where the decrease in oxygen concentration is large as indicated by the change in area (dashed line) when controlled, and the concentration of the inert gas becomes a predetermined value. It is presumed that the oxygen concentration in the optical path space 116 can be efficiently reduced by returning the stage velocity when the opening area becomes 0, as in the concentration change (broken line) when controlled.

Therefore, a method of controlling the stage corresponding to the area change in the above control may be considered.

As a method, a method of measuring the oxygen concentration in the optical path space 116 and controlling the stage based on the measured value (method 1) and the relationship between the stage coordinates / speed and time obtained from the method 1 are described. The method (method 2) that has a table and is applied to the control of the stage, and the relationship between the change of the opening area and the concentration of the inert gas, the supply and exhaust amount of the inert gas, the optical path space
16 and surrounding size, concentration of supply gas, optical path space 11
There is a method (method 3) of obtaining the density and flow velocity of the surrounding atmosphere and the moving speed of the stage by calculation such as simulation. By controlling the stage by applying any one of the methods, the replacement time of the atmosphere in the optical path space 116 can be shortened. The method 1 will be described below.

The target oxygen concentration and the oxygen concentration meter 117 are set using the graph of the concentration change in the case of control shown in FIG. 6 as the target concentration.
The moving speed of the wafer stage 102 is controlled while comparing the values of. In this case, if the oxygen concentration is higher than the target value, the stage speed is decelerated, and if the oxygen concentration is lower than the target value, the stage speed is accelerated. Figure 6
The slope of the graph of the concentration change in the case of control shown in FIG. Depends on the time from the rush completion time to the exposure start time.

A method of determining the slope of the graph of density change in the case of control shown in FIG. 6 will be described below.

In FIG. 7, the wafer stage 102 has the optical path space 1
It is the graph which showed the time change of the oxygen concentration at the time of starting supply of an inert gas in the state which existed under 16.

There is a slight time Δt from the completion time of the entry of the stage 102 under the optical path space 116 to the exposure start time including alignment and the like. Then, the oxygen concentration Δt time before the oxygen concentration Cp at which exposure can be started shown in FIG. 7 is set as the target oxygen concentration Ct when the wafer stage 102 completes the entry under the optical path space 116.

FIG. 8 shows a graph when the target oxygen concentration at the rush completion coordinate B is Ct.

The steady-state concentration graph is the same as the graph shown in FIG. The magnification is set so that the steady slope of the oxygen concentration in the section from the stage coordinate C where the decrease of the oxygen concentration becomes large to the stage coordinate B where the entry is completed becomes the slope of the concentration Cc of the coordinate C to the concentration Ct of the coordinate B. Then, the target concentration is determined from the steady concentration.

FIG. 9 shows the time course of the stage speed when the wafer stage 102 is controlled based on the value of the oxygen concentration meter 117. Further, when the wafer stage 102 is controlled based on the value of the oxygen concentration meter 117, the change in the opening area of the optical path space 116 is almost the same as the graph in the case of control in FIG.

In FIG. 9, A is the rush start time when the height adjusting plate 181 plunges under the optical path space 116, and B is the wafer 103 or the height adjusting plate 181 is the optical path space 116.
It is the rush completion time to complete the rush. Before the time B, the stage is once decelerated and then returned to the normal speed again. By decelerating once, the replacement can be performed in a short time while suppressing the replacement time delay due to the deterioration of the exhaust efficiency in the optical path space 116.

If the amount of supply and exhaust of the inert gas and the size of the optical path space 116 are the same, the stage speed shown in FIG. 9 is held as a table, and the oxygen concentration meter 117 is mounted by controlling the stage based on the table. It is possible to efficiently shorten the replacement time without doing so.

The relationship shown in FIG. 4 is obtained based on the oxygen concentration meter 117 connected to the optical path space 116 and the wafer stage coordinates when the exposure apparatus is started up. Further, the relationship of FIG. 2 is obtained by calculation such as simulation based on the supply amount and exhaust amount of the inert gas, the gas supply concentration, the size of the optical path space 116, and the distance from the lower end of the shielding member 115 to the wafer 103. May be.

As another control example of the wafer stage 102, after a predetermined movement amount step by step movement, after confirming a decrease in oxygen concentration by the oxygen concentration meter 117, further step movement may be performed and this may be repeated. Thereby, the oxygen concentration in the optical path space 116 can be sequentially reduced.

Further, as shown in FIG. 10, the relationship between the time and the wafer stage speed in FIG. 9 and the relationship between the opening area and the time in FIG. 6 are converted into the wafer stage coordinate and the time relationship, and the stage is set as the target coordinate. May be controlled, or a decrease in oxygen concentration may be confirmed every time the wafer stage 102 moves, for example, 5 mm, and the moving speed of the wafer stage 102 may be controlled in accordance with the confirmed oxygen concentration.

The control of the stage controller 132 in this case may be controlled in real time based on the detected value of the oxygen concentration meter 117, or the wafer stage 102 may be controlled according to a table stored in advance.

As described above, according to the first embodiment, by controlling the wafer stage 102 from the relationship between the opening area of the optical path space 116 and the oxygen concentration, the internal atmosphere of the optical path space 116 is made inactive in a shorter time. It is possible to substitute gas.

The gas components other than the inert gas contained in the optical path space 116 include not only oxygen but also gas components contained in the atmosphere such as water vapor and carbon dioxide. And
In particular, in the first embodiment, the wafer stage 102 is controlled based on the oxygen concentration obtained from the oxygen concentration meter 117. However, the concentration of any gas component other than oxygen contained in the atmosphere or a combination thereof is set. The wafer stage 102 may be controlled based on this. Furthermore, the wafer stage 102 may be controlled based on the concentration of the inert gas itself contained in the optical path space 116.

Although the wafer stage 102 is controlled based on the value of the oxygen concentration inside the optical path space 116, the present invention is not limited to this. For example, instead of detecting the oxygen concentration, the pressure inside the optical path space 116 is measured, and the moving speed of the wafer stage 102 is controlled so that the change amount of the pressure value per unit time is suppressed to a predetermined change amount or less. good.

FIG. 11 shows the relationship between the pressure in the optical path space 116, the opening area, and time. Similarly to the above, when the wafer stage 102 is thrust into the optical path space 116 at a constant stage speed, the wafer stage 102 below the optical path space 116 is moved.
The pressure inside the optical path space 116 rapidly rises just before the entry into the optical path space 116. Therefore, as shown in FIG. 11, by reducing the stage speed so as to suppress the decrease rate of the opening area before and after the opening area is minimized in order to suppress the rapid pressure increase, the exhaust efficiency is sharply deteriorated. In this way, the inert gas in the optical path space 116 is replaced in a short time.

Specifically, by slowing or stopping the moving speed of the wafer stage 102 in accordance with the rise in the pressure inside the optical path space 116, it is possible to prevent the exhaust efficiency inside the optical path space 116 from rapidly deteriorating and to be inactive. The replacement time with gas can be shortened.

Further, similarly to the control corresponding to the above density,
If the supply / exhaust amount of the inert gas and the size of the optical path space 116 are the same, the relationship between the stage speed and the time is held as a table, and the wafer stage 102 is controlled based on the table to mount the pressure measuring means. It is possible to efficiently reduce the replacement time.

[Second Embodiment] In the first embodiment, the moving speed and coordinates of the wafer stage 102 are controlled based on the relationship between the opening area of the optical path space 116 and the oxygen concentration.
As shown in, the moving speed of the wafer stage 102 is changed to the maximum moving speed Vmax when the opening area of the optical path space 116 becomes equal to or smaller than a predetermined opening ratio (for example, 50%) of the maximum opening area.
By further reducing the speed, it is possible to shorten the replacement time with the inert gas.

Further, as shown in FIG. 13, the optical path space 11
The opening area of 6 is a predetermined opening ratio (for example,
10%) or less, the wafer stage 102 is stopped, and after the oxygen concentration decreases, the wafer stage 102
It is also possible to shorten the replacement time with the inert gas by moving the gas.

The wafer stage 102 is at a constant speed, but at a speed equal to or lower than the normal moving speed of the wafer stage 102 and optimized for increasing the concentration of the inert gas.
It is also possible to shorten the replacement time with the inert gas by causing the gas to enter under the optical path space 116.

FIG. 14 shows the relationship between the stage speed and the replacement time.

When the stage speed is as low as α or less, it takes a long time to reduce the opening area, which is the main reason for the slow replacement time. On the other hand, when the stage speed is β or more and γ or less, the opening area decreases conversely and exhaust efficiency deteriorates, so that the replacement time tends to be long. However, when the stage speed is γ or higher, the time required for replacement after the opening area is minimized does not change so much, and the reduction time of the opening area becomes a factor to shorten the replacement time.

By obtaining the stage velocity α by experiments or by calculation such as simulation, the stage 102 can be driven under the optical path space 116 while driving the stage at a constant velocity or lower than the normal moving velocity. It is possible to shorten the replacement time with the inert gas.

[Third Embodiment] FIG. 15 is a view showing a part of an exposure apparatus according to the third embodiment of the present invention. In the third embodiment, the replacement time is further shortened by adding / changing the following three configurations to the first and second embodiments.

First, the height of the outside of the wafer 103 held by the wafer chuck 180 on the wafer stage 102 is inclined so that the height change between the wafer 103 and the outside thereof is gentle. An adjusting plate 181 is arranged. The height adjusting plate 181 is provided in the optical path space 116 when the wafer 103 enters the optical path space 116.
The decrease speed of the lower opening area is made slower, and the optical path space 116
Improve the exhaust efficiency of.

Secondly, the air supply units 193 and 194 for blowing the inert gas from the air supply passage into the optical path space 116 via the flow rate controllers 191 and 192 for controlling the flow rate of the inert gas.
To face each other. Also, the optical path space 1
The shielding members on four sides surrounding 16 are arranged, the shielding members on three sides of the shielding members have the same height, and the height of the shielding member on the remaining one side to the wafer 103 is increased. Embodiment 3
Then, the height from the air supply unit 193 located on the downstream side of the flow 195 of the surrounding atmosphere to the wafer 103 is made larger than the other three sides. This is to improve the exhaust efficiency of the optical path space 116 on the downstream side of the surrounding atmosphere that is less susceptible to the flow 195 of the surrounding atmosphere.

Thirdly, the supply amount of the inert gas from the upstream air supply unit 194 of the flow 195 of the surrounding atmosphere is made larger than the supply amount of the inert gas from the downstream air supply unit 193. . From the air supply unit 193 on the downstream side, for example, the optical path space 1
The inert gas is supplied only to the upper part in 16. here,
Since the gas in the optical path space 116 has a strong tendency to flow in the same direction as the gas in the peripheral space, the amount of the inert gas supplied from the upstream air supply unit 194 is reduced by the amount of the inert gas supplied from the downstream air supply unit 193. It is possible to shorten the replacement time with the inert gas in the optical path space 116 by increasing the supply amount. Further, when the inert gas is supplied only from one direction, the replacement of the gas in the part far from the supply port (for example, the part P in FIG. 15) tends to be delayed, so that the supply of the air which is opposed to the opposite side as described above is likely to occur. It is preferable to provide the parts 193 and 194.

Here, FIG. 9 by the exposure apparatus of the first embodiment is shown.
FIG. 16 shows a graph comparing changes in the moving speed of the wafer stage 102 by the exposure apparatus of the third embodiment with respect to changes in the moving speed of the wafer stage 102.

In FIG. 16, the solid line graph shows changes in the moving speed of the wafer stage 102 by the exposure apparatus of the third embodiment, and B ′ is the wafer 103 or the height adjusting plate 1.
Reference numeral 81 is a rush completion time when the rush into the optical path space 116 is completed. Further, the broken line graph shows changes in the moving speed of the wafer stage 102 by the exposure apparatus of the first embodiment.

As is clear from the figure, the rush completion time B'in the third embodiment is earlier than the rush completion time B in the first embodiment. That is, in the third embodiment, the exhaust efficiency in the optical path space 116 before and after the completion of the entry of the stage 102 into the optical path space 116 is improved by the above three points, and the inert gas of the inert gas can be generated without slowing the speed of the stage 102 so much. It shows that the density can be adjusted to the target value. In this way, it is possible to further shorten the replacement time of the optical path space 116 with the inert gas as compared with the exposure apparatuses of the first and second embodiments.

In the third embodiment, the height of one side of the four sides of the shielding member surrounding the optical path space 116 is changed, but the height may be partially changed instead of changing the height of all sides. It is possible to obtain the same effect.

Further, by adding / changing all or part of the above-mentioned three points to the first and second embodiments, it is possible to enhance the exhaust efficiency of the optical path space 116 and further shorten the replacement time.

Further, in the portion marked with P in FIG. 15, as described above, when the inert gas is supplied from only one side, the gas flow tends to be slow. Therefore, when processing the wafer 103 which emits a contaminant, the contaminant tends to accumulate in the portion P. However, the third embodiment
As described above, the inert gas is supplied to the optical path space 116 from the opposing air supply units 193 and 194, and the optical path space 116 is also supplied.
The air supply unit 19 located downstream of the flow of the surrounding atmosphere surrounding the
Such a problem can be solved by increasing the height from 3 to the wafer 103 as compared with the other three sides to increase the flow velocity in the P portion.

[Fourth Embodiment] In the first to third embodiments,
The invention applied between the projection optical system and the wafer stage can also be applied between the illumination optical system and the reticle stage and between the reticle stage and the projection optical system. FIG. 17 shows the present invention between the projection optical system and the wafer stage, between the illumination optical system and the reticle stage,
It is a figure which shows the exposure apparatus applied between the reticle stage and the projection optical system.

In the exposure apparatus shown in FIG. 17, the projection optical system 3
02, the first optical path space 3 between the final optical member (cover glass) 311 and the wafer chuck 303 (wafer 305).
Regarding No. 14, the first air supply unit 341 for supplying the inert gas to the first optical path space 314, the first A flow controller 312 for controlling the supply amount of the inert gas, and the first optical path space 3
First exhaust unit 342 for exhausting an inert gas or the like from 14 and a first B flow rate controller 31 for controlling the exhaust amount of the inert gas or the like
3 is provided. Then, with these configurations, the first
An inert gas is supplied to the optical path space 314, and the first to third embodiments are provided.
With the stage control described above, the replacement time can be shortened by causing the wafer stage 102 to enter the first optical path space 314.

Regarding the second optical path space 326 between the illumination optical system 301 for illuminating the reticle (mask) 322 and the reticle stage 321 (reticle 322), the second optical path space 326 is supplied with an inert gas. 2 Air supply unit 3
51 and a second A flow rate controller 327 that controls the supply amount of the inert gas, a second B exhaust unit 352 that exhausts the inert gas and the like from the second optical path space 326, and a discharge amount of the inert gas and the like. A two-flow controller 328 is provided. Then, with these configurations, the inert gas is supplied to the second optical path space 326, and the reticle stage 321 is rushed into the second optical path space 326 by the stage control of the first to third embodiments to shorten the replacement time. Is possible.

The third optical path space 325 between the reticle stage 321 and the projection optical system 302 is the third optical path space 325.
Third air supply unit 34 that supplies an inert gas to the optical path space 325
5 and a third A flow rate controller 323 that controls the supply amount of the inert gas, a third exhaust unit 346 that exhausts the inert gas and the like from the third optical path space 325, and a control unit that controls the exhaust amount of the inert gas and the like. A 3B flow controller 324 is provided.
Then, with these configurations, an inert gas is supplied to the third optical path space 325, and the reticle stage 321 is rushed into the third optical path space 325 by the stage control of Embodiments 1 to 3, thereby shortening the replacement time. Is possible.

In this way, the first to third optical path spaces 31
An inert gas (for example, nitrogen gas or helium gas) is supplied to 4, 326, and 325, and the stage control of Embodiments 1 to 3 shortens the replacement time with the inert gas in each optical path space.

However, by controlling the same reticle stage 321, the second optical path space 326 and the third optical path space 325 realize the reduction of the replacement time with the inert gas. for that reason,
By setting the target value based on the average value of the oxygen concentration meters 333 and 332 or controlling the reticle stage 321 based on either value of 332 and 333, the inert gas in each optical path space is controlled. It enables to shorten the replacement time.

As in the first embodiment, the first to third oximeters and the reticle stage 32 shown in FIG.
1 is controlled by the stage controller 132 in synchronism with the wafer stage 304, and the 1A to 3A and 1B to 3B flow rate controllers are controlled by the environment controller 131. Environmental controller 131 and stage controller 13
2 and other controllers not shown are the main controller 1
By 33, the overall control is performed in various operations such as wafer exchange, alignment operation, and exposure operation. The monitoring device 134 monitors the control content of the main controller 133 and the operating state of the exposure apparatus.

[Application Example of Exposure Apparatus] Next, a semiconductor device manufacturing process using the above-described exposure apparatus will be described.

FIG. 18 shows the flow of the whole semiconductor device manufacturing process.

In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask making), a mask is made based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the mask and wafer described above.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer manufactured in step 4, including an assembly process (dicing, bonding), a packaging process (chip encapsulation). Etc. including the assembling process. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. The semiconductor device is completed through these processes, and is shipped in step 7.

FIG. 19 shows the detailed flow of the wafer process.

In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern is transferred onto the wafer by the above-mentioned exposure apparatus. In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist peeling), the unnecessary resist after etching is removed. By repeating these steps,
Multiple circuit patterns are formed on the wafer.

[0113]

As described above, according to the present invention,
For example, a space between the projection optical system and the substrate, a space between an illumination optical system that illuminates a mask (for example, a reticle) and a mask stage that holds the mask, or a space between the mask stage and the projection optical system. Exposure apparatus capable of shortening the time required to replace a gas in an optical path space including a space (exposure region) through which exposure light passes, such as the above space, a control method therefor, and a device manufacturing method Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a part of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining an opening area according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a progress in the process of reducing the opening area according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between an opening area of an optical path space and oxygen concentration according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an opening area, stage coordinates, and oxygen concentration according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a time course of an opening area and oxygen concentration according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between oxygen concentration and time according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between oxygen concentration, an opening area, and stage coordinates according to the first embodiment of the present invention.

FIG. 9 is a diagram showing the progress of the stage speed when entering the optical path space according to the first embodiment of the present invention.

FIG. 10 is a diagram showing the progress of stage coordinates when entering the optical path space according to the first embodiment of the present invention.

FIG. 11 is a diagram showing a time course of the opening area and the pressure in the optical path space according to the first embodiment of the present invention.

FIG. 12 is a diagram showing the progress of the stage speed when entering the optical path space according to the second embodiment of the present invention.

FIG. 13 is a diagram showing the progress of the stage speed when entering the optical path space according to the second embodiment of the present invention.

FIG. 14 is a diagram showing a relationship between a stage speed and a replacement time according to the second embodiment of the present invention.

FIG. 15 is a diagram showing a state when plunging into an optical path space according to the third embodiment of the present invention.

FIG. 16 is a diagram showing the progress of the stage speed when entering the optical path space according to the third embodiment of the present invention.

FIG. 17 is a diagram showing a part of an exposure apparatus including a reticle periphery according to a fourth embodiment of the present invention.

FIG. 18 is a flowchart of the overall manufacturing process of a semiconductor device.

FIG. 19 is a flowchart of the overall manufacturing process of a semiconductor device.

FIG. 20 is a diagram showing a part of a conventional exposure apparatus.

Claims (27)

[Claims] 1. An exposure apparatus for projecting and transferring a pattern formed on a mask onto a substrate by using exposure light, comprising: a stage, an optical system, and exposure light passing between the stage and the optical system. A gas flow forming mechanism for forming a flow of an inert gas in an optical path space including a space, and based on either the concentration of a predetermined gas inside the optical path space or the pressure inside the optical path space, An exposure apparatus comprising: a control unit that controls the movement of the stage when the stage moves. 2. The exposure apparatus according to claim 1, wherein the control unit controls the stage so that a moving speed of the stage becomes less than a maximum moving speed. 3. The control unit is configured to decelerate the stage,
Alternatively, the exposure apparatus according to claim 1, wherein the stage is controlled so as to be temporarily stopped. 4. The control unit controls the stage so as to decelerate or temporarily stop the stage before the opening area of the optical path space is minimized. Exposure equipment. 5. The predetermined gas is either the inert gas or a gas component in the atmosphere other than the inert gas, or a combination thereof.
The exposure apparatus according to. 6. The exposure apparatus according to claim 1, further comprising a concentration measuring unit arranged in the optical path space for measuring the concentration of the predetermined gas. 7. The movement of the stage is performed by the control means after stepping the stage by a predetermined movement amount step, confirming that the predetermined gas has reached a predetermined concentration, and further moving the step step repeatedly. 7. The exposure apparatus according to claim 6, wherein the exposure apparatus is controlled. 8. The method according to claim 6, wherein the control means controls the movement of the stage while confirming that the predetermined concentration of the predetermined gas corresponding to the movement amount of the stage has been reached. Exposure equipment. 9. A target concentration determined from the concentration of the predetermined gas by obtaining the relationship between the opening area of the optical path space determined by the position of the optical path space and the stage and the concentration of the predetermined gas in the optical path space. 7. The exposure apparatus according to claim 6, wherein the movement of the stage is controlled when the stage moves below the optical path space based on the above. 10. The exposure apparatus according to claim 9, wherein the target density is a value obtained by multiplying an ultimate density determined by the opening area by a predetermined magnification. 11. The control means controls the movement of the stage by referring to a table stored in advance in association with the time series of the opening area and the concentration of the predetermined gas. 1. The exposure apparatus according to 1. 12. The movement of the stage is controlled by referring to a table stored in advance in association with a time series of the supply amount of the inert gas to the optical path space, the opening area, and the concentration of the predetermined gas. The exposure apparatus according to claim 1, wherein: 13. The pressure measuring means, which is arranged in the optical path space and measures the pressure inside the optical path space, further includes: a pressure measuring means, wherein the control means moves the stage based on a measurement result of the pressure measuring means. The exposure apparatus according to claim 1, which is controlled. 14. The control means controls the moving speed of the stage such that the amount of change in the pressure per unit time is equal to or less than a predetermined amount of change.
The exposure apparatus according to. 15. The control means controls the movement of the stage so as to decelerate or temporarily stop the moving speed of the stage when the pressure rises above a predetermined pressure. Item 3. The exposure apparatus according to item 3. 16. The gas flow forming mechanism includes a supply mechanism that supplies an inert gas to the optical path space and at least a supply mechanism that exhausts a gas containing an inert gas from the optical path space. The exposure apparatus according to claim 1, wherein: 17. The exposure apparatus according to claim 16, wherein the supply mechanism has two gas supply units arranged at positions facing each other across the optical path space. 18. A substrate stage, a substrate chuck mounted on the substrate stage, and a height adjusting member for smoothing a height change between the substrate chucked by the substrate chuck and its periphery. The exposure apparatus according to claim 16, further comprising: 19. The exposure according to claim 16, further comprising a shield member having four sides surrounding the optical path space, wherein the height of one side of the shield members of the four sides is different from that of the other three sides. apparatus. 20. The exposure according to claim 1, wherein the gas flow forming mechanism is arranged so as to form a flow of an inert gas in an optical path space between the projection optical system and the substrate. apparatus. 21. The gas flow forming mechanism is arranged so as to form a flow of an inert gas in an optical path space between an illumination system that illuminates a mask and a mask stage that holds the mask. The exposure apparatus according to claim 1. 22. The gas flow forming mechanism is arranged so as to form a flow of an inert gas in an optical path space between a mask stage holding a mask and a projection optical system. 1. The exposure apparatus according to 1. 23. The gas flow forming mechanism, wherein the first gas flow forming mechanism is arranged to form a flow of an inert gas in a first optical path space between the projection optical system and the substrate, and the mask is illuminated. A second gas flow forming mechanism arranged so as to form a flow of an inert gas in a second optical path space between the illumination system and the mask stage holding the mask, the mask stage and the projection optical system. And a third gas flow forming mechanism arranged to form a flow of the inert gas in the third optical path space between the two.
The exposure apparatus according to. 24. The supply amount of the inert gas supplied to the optical path space by the gas flow forming mechanism is equal to or larger than the exhaust amount of the gas containing the inert gas. Exposure equipment. 25. The exposure apparatus according to claim 1, wherein the predetermined gas is nitrogen gas or helium gas. 26. A mask, comprising: a stage, an optical system, and a gas flow forming mechanism for forming a flow of an inert gas in an optical path space including a space through which exposure light passes between the stage and the optical system. A method of controlling an exposure apparatus, which projects and transfers a pattern formed on a substrate using exposure light, the derivation step of deriving a concentration of a predetermined gas inside the optical path space, and the concentration derived by the derivation step. And a control step of controlling the movement of the stage when the stage moves to below the optical path space. 27. A device manufacturing method, comprising: a transfer step of transferring a pattern onto a substrate coated with a photosensitive material using an exposure apparatus; and a developing step of developing the substrate, wherein the exposure apparatus comprises: A stage, an optical system, a gas flow forming mechanism for forming a flow of an inert gas in an optical path space including a space where the exposure light passes between the stage and the optical system, and a predetermined gas in the optical path space. A device manufacturing method, comprising: a control unit that controls the movement of the stage when the stage moves to below the optical path space based on the concentration.