JPH05129181A - Exposure apparatus - Google Patents

Abstract

PURPOSE:To improve the throughput of an exposure apparatus without decreasing an alignment accuracy by providing a second chamber separately from a first chamber, and so constituting it that environmental conditions around a photosensitive substrate contained in the second chamber can be arbitrarily controlled. CONSTITUTION:A plate carrier PC1 containing a glass plate PT to be conveyed to an exposure processor PE is contained in a subchamber SC separately from a main chamber MC containing the processor PE so as to substantially shut OFF from the atmosphere. A chamber controller controls environmental conditions in the subchamber SC and particularly the temperature, and the temperature of the plate PT in the carrier PC1 is set to a predetermined value. Thus, the temperature of the plate PT before being conveyed to the processor can be set to an optimum temperature, i.e., substantially equal to the temperature of a plate stage PS, and an exposure operation for the plate can be started immediately in the processor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for manufacturing semiconductor elements, liquid crystal display elements and the like, and more particularly to an apparatus for controlling the environmental conditions in a chamber which houses the exposure apparatus while being substantially shielded from the outside air. Is.

[0002]

2. Description of the Related Art In recent years, masks or reticles (hereinafter
A pattern of a reticle) is used as a photosensitive substrate (semiconductor wafer or glass plate on which a resist layer is formed)
A projection exposure apparatus (stepper) of a step-and-repeat method is often used as an apparatus for transferring the image onto the top. For example, in a stepper for manufacturing a liquid crystal display element, an image of each reticle pattern is equally magnified through a projection optical system while a plurality of reticles are exchanged, and sequentially transferred onto a glass plate while stepping a plate stage. Go As a result, it is possible to form a large-area circuit pattern on the glass plate, which is screen-synthesized (joined).

This type of stepper includes a projection optical system for forming and projecting an image of a reticle pattern on a glass plate, and a plate stage which holds the glass plate and is two-dimensionally movable within the image forming plane of the projection optical system. And an at least one holding member capable of holding the glass plate, the glass plate held by the holding member is carried into the exposure processing unit, and the exposure processing is performed at the exposure processing unit. It is composed of a substrate transfer section that transfers the glass plate to the same or different holding member. As the holding member, for example, a plate storage carrier capable of accommodating a plurality of (about 10 to 20) glass plates, or for adjusting the cycle time of plate transportation when a stepper and a coater / developer are inlined There is a buffer cassette that temporarily stores a glass plate.

In the stepper having the above-described structure, an image is formed on the projection optical system by a change in environmental conditions (atmospheric pressure, temperature, humidity, etc.) around the projection optical system, and further by a temperature change due to absorption of exposure light of the projection optical system. The characteristics (focal position, projection magnification, etc.) may vary. Therefore, the entire apparatus (exposure processing section and substrate transfer section) is maintained at a constant temperature (for example, 23 ° ± 0.1 ° C),
It is housed in a chamber controlled to a certain degree of cleanliness (for example, class 10) while being substantially shielded from the outside air. Moreover, there is also proposed a technique for efficiently preventing the variation of the image forming characteristic by managing the temperature of only the projection optical system which has an important influence on the image forming characteristic by using the fluid whose temperature is controlled highly. There is.

[0005]

In the prior art as described above, the stepper is used in a chamber whose temperature is controlled with an accuracy of about ± 0.1 ° C. Alternatively, when glass plates are carried into the chamber one by one, the glass plates equilibrate to a temperature substantially equal to the temperature in the chamber. However, the plate stage (particularly the holder) of the exposure processing unit has thermal energy that is conducted and accumulated in the stage through the glass plate during pattern exposure on the glass plate, or a drive system of the plate stage (for example, a feed screw mechanism). In this case, the temperature is equilibrated to a temperature different from the temperature inside the chamber by heat generated from a nut screwed to the feed screw). Therefore, the glass plate taken out from the plate carrier by the substrate transfer device (plate loader) and placed on the plate stage (holder) of the exposure processing unit has a temperature difference with the plate stage (holder) of substantially zero. The temperature continues to change until it equilibrates to a temperature almost equal to the temperature of the plate stage.

Therefore, the glass plate continues to undergo dimensional changes until the temperature of the glass plate reaches an equilibrium state. Therefore, if pattern exposure is performed on the glass plate during this time, a plurality of reticle patterns on the glass plate are formed. There is a problem that the accuracy of joining or the accuracy of overlaying (aligning) a projected image of a reticle pattern with a pattern already formed on a glass plate decreases. In order to prevent this, the temperature difference between the glass plate and the plate stage (holder) becomes negligible or almost zero (in other words, the deterioration of the joining accuracy and the alignment accuracy due to the dimensional change of the glass plate is predetermined. It is necessary to stop the exposure operation up to the allowable value (the value is determined by the pattern line width etc.), but there is a problem that this stop time reduces the throughput of the exposure apparatus.

The present invention has been made in consideration of the above points, and the alignment accuracy (or the connection accuracy) and the throughput due to the dimensional change of the photosensitive substrate in the exposure processing section until the photosensitive substrate is thermally equilibrated can be obtained. The purpose of the present invention is to obtain an exposure apparatus that can prevent the deterioration.

[0008]

In order to solve such a problem, in the present invention, an exposure processing part PE for transferring a pattern formed on a reticle R onto a photosensitive substrate (glass plate) PT, and a photosensitive substrate PT. Having at least one holding member (plate carrier PC ₁ , PC ₂ ) capable of holding the substrate, the photosensitive substrate PT held by the holding member PC ₁ is carried into the exposure processing unit PE, and the exposure processing unit PE performs the exposure processing. The holding member PC ₁ or P
A first chamber (main chamber) M for accommodating the substrate transfer part PL which is carried out to C ₂ while being substantially shielded from the outside air.
In the exposure apparatus including C, apart from the first chamber MC, at least the holding member PC ₁ holding the photosensitive substrate PT to be carried into the exposure processing unit PE is housed while being substantially shielded from the outside air ( Sub chamber) SC
And control means (temperature controller 20, chamber controller 100) for controlling the environmental conditions around the photosensitive substrate of the holding member housed in the second chamber SC.

[0009]

In the present invention, in addition to the first chamber in which the exposure processing section and the like are stored, at least the holding member that holds the photosensitive substrate to be carried into the exposure processing section is stored while being substantially shielded from the outside air. In addition to the above chamber, the environmental conditions (especially temperature) around the photosensitive substrate housed in the second chamber can be arbitrarily controlled.

Therefore, the temperature of the photosensitive substrate before being carried into the exposure processing unit can be set to be substantially equal to the temperature of the stage (holder) in the exposure processing unit. Therefore, it is not necessary to stop the exposure operation until the photosensitive substrate is in thermal equilibrium in the exposure processing section, and it is possible to improve the throughput of the exposure apparatus without lowering the alignment (or joining) accuracy. It will be possible.

[0011]

1 is a diagram showing a schematic overall structure of an exposure apparatus according to an embodiment of the present invention, in which the exposure apparatus housed in a chamber is viewed from above. As shown in FIG. 1, in the present embodiment, the entire apparatus is housed in two sets of chambers MC and SC that are substantially shielded from the outside air. The main chamber (first chamber of the present invention) MC is an exposure processing unit P having a projection optical system 7 for image-projecting a reticle pattern on a glass plate.
The sub-chamber (second chamber of the present invention) SC containing E includes two sets of plate carriers PC ₁ and PC ₂ , and the glass plate housed in the carrier PC ₁ (or PC ₂ ) is used as the exposure processing part PE. And a substrate transfer section (plate loader) PL that transfers the glass plate that has been subjected to the exposure processing by the exposure processing section PE to the carrier PC ₁ or PC ₂ .

In this embodiment, the glass plate to be carried into the exposure processing unit PE is housed in the carrier PC ₁ , and the glass plate on which the pattern is transferred by the exposure processing unit PE and taken out from the carrier PC ₁ is the plate loader PL. Shall be stored in the carrier PC ₂ . Also,
As shown in FIG. 1, the glass plate can be transported between the main chamber MC and the sub-chamber SC,
An opening AP is formed in a part of the boundary.

The plate carriers PC ₁ and PC ₂ can move up and down, that is, a support member E that can move in a direction perpendicular to the paper surface.
The supporting members EV ₁ and EV are mounted on the V ₁ and EV _2.
By lowering the _2, door SD _1, supported by a SD ₂ member EV _1, EV ₂ and carrier transport wagon PW
Carriers PC ₁ and PC ₂ are delivered to and from. Further, in FIG. 1, an environment for detecting environmental conditions (temperature, atmospheric pressure, etc.) in the sub-chamber SC, particularly in the present embodiment, around the plate carrier PC ₁ holding a glass plate to be carried into the exposure processing unit PE. A sensor 26 is arranged.

In this embodiment, only the temperature of the glass plate in the carrier PC ₁ or its surroundings can be detected. For example, the glass plate (or carrier PC ₁ )
The temperature may be measured directly or indirectly by a temperature sensor. Further, since the glass plate in the plate carrier PC ₂ may be carried into the exposure processing unit PE, it is desirable to dispose the environment sensor in the vicinity of the carrier PC ₂ as well.

FIG. 5 is a perspective view showing a specific construction of the plate loader PL, and the back surface of the glass plate PT in the carrier PC ₁ is taken out by vacuum suction by the carrying member (arm) 70. Each of the plurality of glass plates in the carrier PC ₁ causes a a carrier PC ₁ and the transfer arm 70 is relatively moved in the Z-direction, i.e. the carrier PC ₁ is moved up and down by a support member EV ₁ (FIG. 1) in this embodiment As a result, the carrier arm 70 takes out the carrier PC ₁ .

The transfer arm 70 holding the glass plate PT is rotated 90 ° in the XY plane, and then the glass plate PT is transferred to the transfer arm 70 by a pre-alignment mechanism 71 attached to an arm swivel unit (not shown). Aligned to. The pre-aligned glass plate PT is transferred to a load arm 73 via a transfer table 72 that is movable in the Z direction, and the plate arm PS that stands by at a predetermined position in the exposure processing unit PE by the load arm 73. And is adsorbed to the holder PH. The transfer table 72 is capable of rotating the glass plate PT by 90 ° and transferring it to the load arm 73 when necessary.

The glass plate PT to which the pattern has been transferred by the exposure processing unit PE is taken out by the transfer arm 70 reaching the plate stage PS, and the glass plate PT 90 is transferred onto the transfer table 72 when necessary.
After being rotated, it is stored in the carrier PC ₂ (Fig. 1).
In order to speed up the exchange of the glass plate, the next glass plate may be held by the load arm 73 during the exposure operation of the glass plate.

Next, the structure of the exposure processing part PE will be briefly described with reference to FIG. In the apparatus shown in FIG. 4, at least the projection optical system 7 and the plate stage PS are arranged in the chamber room MR. In FIG. 4, a reticle stage RS holds _four reticles R _{1 to} R ₄ , and each reticle is set above a projection optical system 7 by a laser interferometer 5 and a motor 6. Reticle R
Each of _{1 to} R ₄ is X, Y, θ on the reticle stage RS.
The reticle alignment system 3X, 3Y, and 3θ (3X is a mirror 4)
By finely moving the reticle using only X, the reticle is positioned so that the center point of the pattern area to be transferred is substantially aligned with the optical axis AX of the projection optical system 7.

The illumination light that has passed through the reticle R ₂ is incident on the projection optical system 7 that is telecentric on both sides, and the projection optical system 7 forms a projection image of the reticle pattern at the same size and a resist layer is formed on the surface thereof. Image-project on a glass plate PT held so as to substantially coincide with the image-forming plane of the projection optical system 7. The glass plate PT is mounted on the plate stage PS via a plate holder (not shown). The plate stage PS is configured to be two-dimensionally movable by the step-and-repeat method by the motor 9, and when the transfer exposure of the reticle R ₂ onto the glass plate PT is completed, it is stepped to the next shot position. The two-dimensional position of the plate stage PS is constantly detected by the interferometer 8 with a resolution of, for example, about 0.01 μm. A temperature sensor 30 for measuring the temperature of the stage or holder is provided on the plate stage PS. Further, in FIG. 4, T as disclosed in, for example, JP-A-60-130742 is used.
A TL (Through The Lens) type alignment system 31 is also provided. The control device 50 is a reticle stage RS.
In addition to controlling the position of the plate stage PS, it also controls the entire apparatus.

Now, returning to the explanation of FIG. 1, in the main chamber MC, the exposure processing part PE is arranged in the chamber room MR surrounded by the HEPA filter 12, the partition (wall) 14, the return duct 15 and the like. The environmental conditions inside the chamber room MR, especially the temperature, depend on the air conditioner room 1
By controlling the temperature of the gas (air) in the main chamber MC to circulate it by a temperature controller 10, a fan 11, a refrigerator 13 and the like provided in 7, a predetermined temperature (2
It is controlled to about 3 ° C). At this time, for example, the environment (or temperature) sensor 16 arranged near the projection optical system 7
Based on the detection result of the chamber controller 100
The temperature inside the chamber room MR is maintained at a predetermined temperature by controlling the temperature controller 10 (FIG. 3).

The arrow shown in FIG. 1 represents the direction of air flow (circulation path) in the main chamber MC.
In the chamber room MR, it flows substantially along the boundary with the sub-chamber SC. The air may flow in the chamber room MR in any direction, but it is, of course, desirable that the air does not flow toward the sub chamber SC, that is, the opening AP. The pressure of the gas flowing into the chamber room MR may be controlled together with the temperature.

Next, referring to FIG. 2, the sub-chamber SC
An example of a specific configuration of will be described. FIG. 2 shows a state in which the sub-chamber SC shown in FIG. 1 is viewed from the front (direction of the wagon PW).
The plate loader PL together with C ₁ and PC ₂ (not shown)
It is housed in a chamber room SR in which at least a temperature-controlled gas (air) is circulated via a HEPA filter 22 and a return duct 25. Environmental conditions in the chamber room SR, especially a plate carrier PC containing a glass plate to be carried into the exposure processing part PE.
The temperature around ₁ is predetermined by controlling the temperature of the gas (air) in the sub-chamber SC by the temperature controller 20, the fan 21, the refrigerator 23, etc. provided in the air conditioner room 27 to circulate it. The temperature can be set. Similar to the main chamber MC, the temperature setting of the chamber room SR is based on the detection result of the environment (or temperature) sensor 26 and further the temperature sensor 30 (described later) provided on the plate stage (holder) PS in the exposure processing unit PE. On the basis of,
The chamber controller 100 (FIG. 3) is the temperature controller 2
It is performed by controlling 0.

The arrow shown in FIG. 2 indicates the sub-chamber S.
The flow direction (circulation path) of air whose temperature is controlled in C is shown, and in the chamber room SR, it flows from the boundary portion (opening AP) with the main chamber MC toward the return duct 25. In the present embodiment, because of the configuration, the openings (the inlets and outlets of the glass plates) of the two sets of plate carriers PC ₁ and PC _{2 in} the chamber room SR are substantially parallel to the air flow direction, so they are stored inside. In order to improve the efficiency of temperature control of the formed glass plate, for example, a plurality of holes (openings) are formed in the side surfaces of the carriers PC ₁ and PC ₂ (surfaces substantially perpendicular to the air flow direction) to control the temperature. The generated air is the carrier PC ₁ ,
It is desirable that the glass plate be configured to flow substantially along each glass plate in the PC ₂ . Also, chamber room SR
The air may flow in any direction, and may flow from the carrier PC ₁ to the carrier PC ₂ in FIG. 1, for example. However, it is desirable that the air from the HEPA filter 22 should not flow toward the main chamber MC, that is, the opening AP.

In the apparatus having the above structure, the chamber controller 100 has the environment sensor 1 as shown in FIG.
It is possible to independently control each of the temperature controllers 10 and 20 based on the detection results of the temperature sensors 6 and 26 and the temperature sensor 30 and arbitrarily set the temperature of each gas circulating in the chambers MR and SR. ing. Therefore, the glass plate in the plate carrier PC ₁ stored in the sub-chamber SC for performing the exposure process is stored as stock and, at the same time, the air temperature in the chamber room SR,
That is, the temperature equilibrates to a temperature substantially equal to the temperature of the plate stage (more precisely, the plate mounting surface (holder surface)) in the exposure processing unit PE. Therefore, when the glass plate in the plate carrier PC ₁ is loaded on the plate stage, the temperature difference between the glass plate and the plate stage (holder) has already become almost zero, and the glass plate on the plate stage has a temperature difference of almost zero. Since the dimensional change does not occur, the exposure operation can be started immediately.

In the above embodiment, the two sets of plate carriers PC ₁ and PC ₂ and the plate loader PL were housed in the sub-chamber SC, but the carrier containing the glass plate to be carried into the exposure processing part PE. Only the sub chamber may be stored in the sub chamber SC. For example, the glass plate housed in the carrier PC ₁ is used as the exposure processing unit PE.
After the pattern is transferred with, the same carrier PC ₁ again
In the case of storing in the sub chamber SC, only the carrier PC ₁ may be stored in the sub chamber SC. At this time,
Except for the carrier PC ₁ , it will be housed in the main chamber MC. Further, when the stepper and the coater developer are in-line, the glass plate having the resist layer formed on the surface may be carried into the main chamber via the sub chamber. When inline as described above, a holding member (for example, a buffer cassette or the like) for adjusting the transport time of the glass plate is provided in the transport path, so that the buffer cassette is stored in the sub-chamber. Just do it.

Further, in the present embodiment, the temperature of the glass plate is controlled according to the temperature of the plate stage (holder), but when the temperature change of the plate stage is small, the temperature of the glass plate is kept constant. That is, the temperature may be constantly controlled to a predetermined temperature within the temperature change range of the plate stage. Further, it is not necessary to control the temperature of the glass plate so as to be substantially equal to the temperature of the plate stage, and for example, the amount of dimensional change of the glass plate caused by the temperature difference between the glass plate and the plate stage has a predetermined allowable value ( It suffices to control the temperature of the glass plate within a temperature range that is within a value that is uniquely determined by alignment accuracy, joining accuracy, and the like.

In the above embodiment, the temperature-controlled air is circulated in the sub-chamber SC in order to control the temperature of the glass plate to a desired temperature. However, other methods such as the exposure processing part PE are used. The temperature may be controlled by heating (or cooling) the plate carrier (or buffer cassette) accommodating the glass plate to be loaded into the glass plate or the glass plate by a temperature adjusting means such as a Peltier element. Further, when adopting such a configuration, it is not necessary to provide a sub-chamber, and the plate carrier PC _{1 and}
Can be stored in the main chamber. However, considering the temperature control accuracy of the glass plate,
It is desirable to arrange at least the carrier PC ₁ in the sub chamber. The gas circulated in the sub chamber SC may be helium or the like instead of air. In addition to the method of circulating the temperature-controlled gas, when only the temperature of the glass plate is directly or indirectly controlled, a fluid (water or the like) may be used in addition to the gas.

Further, in order to speed up the exchange of the glass plate, when the sequence in which the loader arm 73 keeps the next glass plate on standby during the exposure operation is adopted, the standby time at the loader arm 73 is increased. in view of,
It is desirable to set the temperature of the glass plate in the sub chamber SC to a high temperature in advance. Further, in the above embodiment, the temperature of the glass plate PT is balanced with the temperature of the plate stage PS by setting the temperature in the sub-chamber SC to be substantially equal to the temperature of the plate stage PS. Positively controls the temperature in the sub-chamber SC (that is, the temperature of the air to be circulated) so that the temperature of the plate stage PS becomes equal to the temperature of the plate stage PS. For example, a plate carrier (or a glass plate) is housed in the sub-chamber. Immediately after the heating, the temperature is set higher than the temperature of the plate stage PS, and when the temperature of the glass plate PT becomes substantially equal to the temperature of the plate stage PS, the temperature may be set substantially equal to the temperature of the plate stage PS. good.

Further, the plate stage PS may be provided with a temperature adjusting mechanism so that, for example, the temperature of the stage is controlled to be always constant. In this case, there is an advantage that the temperature control in the sub-chamber SC (correctly, the temperature control of the glass plate) becomes very easy. More positively, the temperature of the plate stage may be controlled according to the temperature of the glass plate placed next on the plate stage so that the temperature difference between the two becomes substantially zero. At this time, the temperature of the glass plate subsequently placed on the plate stage may be controlled to a predetermined value by a sub-chamber or the like, or the temperature may not be controlled at all without providing the sub-chamber or the like.

By the way, in the above embodiment, the temperature difference between the glass plate and the plate stage was focused on. However, since the same problem can occur between the reticle and the reticle stage, before being transferred to the reticle stage. Alternatively, the temperature of the reticle may be controlled to a predetermined value. Also at this time, the storage unit (including the reticle case etc.) for storing the reticle before being transported to the reticle stage is separated from the main chamber MC and is substantially shielded from the outside air just as in the above embodiment. It may be configured to be housed inside and to control its temperature to a predetermined value. Alternatively, the reticle temperature can be controlled directly, but if the stock system that can store hundreds more reticles and the stepper are inline, the reticle temperature can be controlled within the stock system. It doesn't matter.

In the present invention, the structure of the main chamber (first chamber) and its temperature adjusting mechanism may be arbitrary, and the exposure processing part PE may be of a proximity type other than the projection type. Further, the present invention can be applied to an exposure apparatus for manufacturing a semiconductor in exactly the same manner.

[0032]

As described above, according to the present invention, the photosensitive substrate before being transferred to the exposure processing unit (substrate stage) is separated from the outside air in addition to the first chamber accommodating the exposure processing unit and the like. Since it is blocked and stored in the second chamber and its temperature is maintained at a predetermined optimum temperature, the temperature of the photosensitive substrate is stabilized after being carried into the exposure processing section (that is, a thermal equilibrium state is reached). It is possible to obtain the effect of shortening the time until. In addition, by positively controlling the temperature in the second chamber, that is, the temperature of the photosensitive substrate according to the temperature of the exposure processing unit (substrate stage), the temperature of the photosensitive substrate can be controlled in the shortest time. It is possible to set the temperature substantially equal to the temperature of (1), and it is possible to further improve the throughput of the exposure apparatus. At this time, since the amount of dimensional change of the photosensitive substrate is within a predetermined allowable value or almost zero, it is possible to prevent a decrease in alignment accuracy and joining accuracy due to the dimensional change.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic overall configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a specific configuration of a sub chamber (second chamber) shown in FIG.

FIG. 3 is a block diagram showing an example of the configuration of an exposure apparatus according to an embodiment of the present invention, particularly a control system for two chambers.

FIG. 4 is a plan view showing a specific configuration of an exposure processing unit.

FIG. 5 is a perspective view showing a specific configuration of a substrate transfer section (plate loader).

[Explanation of symbols]

10, 20 Temperature controller 11, 21 Fan 12, 22 HEPA filter 16, 26 Environmental sensor (temperature sensor) 30 Temperature sensor PE Exposure processing part PL Substrate transfer part PC ₁ , PC ₂ Plate carrier 100 Chamber controller

Claims (3)

[Claims] 1. An exposure processing unit for transferring a pattern formed on a mask onto a photosensitive substrate, and at least one holding member capable of holding the photosensitive substrate, the photosensitive substrate being held by the holding member. While carrying in the exposure processing unit,
An exposure apparatus comprising: a first chamber that stores a photosensitive substrate that has been subjected to an exposure process in the exposure processing unit and that is carried out to the holding member while being substantially shielded from the outside air; Separately, a second chamber that stores at least the holding member that holds the photosensitive substrate to be carried into the exposure processing unit while being substantially shielded from the outside air; and a photosensitive member for the holding member that is stored in the second chamber. An exposure apparatus comprising: a control unit that controls environmental conditions around the substrate. 2. The gas circulation means for controlling at least the temperature of the gas in the second chamber and flowing the controlled gas substantially along the photosensitive substrate held by the holding member. The exposure apparatus according to claim 1, comprising: 3. The control means controls the temperature of the gas in the second chamber based on the temperature of the photosensitive substrate arranged in the exposure processing section in the first chamber or its periphery. The exposure apparatus according to claim 2, wherein: