JPH1064809A - Device and method for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an improperly exposed photosensitive substrate from being sent to the next treatment process. SOLUTION: A stage controller 76-1 successively monitors the position coordinates of a substrate stage 64 through an interferometer 56 during exposure and, at the same time, judges whether or not the deviation of the present position coordinates of the stage 64 from target coordinates falls within a tolerance at the time of exposure based on the monitored results and, when the deviation exceeds the tolerance, outputs an abnormality signal. Therefore, it becomes possible to urgently stop an exposing device based on the abnormality signal and a photosensitive substrate 52 which is improperly exposed owing to the position error of the stage 64 can be removed quickly. In addition, the exposing device can be corrected or adjusted simultaneously with the removal of the improperly exposed photosensitive substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and an exposure method, and more particularly, to an exposure apparatus and an exposure method used in a photolithography process in manufacturing a semiconductor memory or a liquid crystal display substrate (LCD panel).

[0002]

2. Description of the Related Art Conventionally, in a photolithography process during the manufacturing process of a semiconductor device or a liquid crystal display device, a circuit pattern formed on a mask is projected onto a photosensitive substrate such as a wafer or a plate via a projection optical system. A projection exposure apparatus that performs projection exposure is used. As one of the projection exposure apparatuses, a step-and-repeat type reduction projection type exposure apparatus, that is, a so-called stepper is used relatively frequently.

This stepper exposes a photosensitive substrate by a step-and-repeat method via a projection optical system having an exposure field that can include the entire pattern of one mask (reticle). This stepper
There is an advantage that resolution, overlay accuracy, and the like are higher than an aligner or the like employing a scan exposure method.

[0004]

In the above-described conventional stepper, a substrate stage movable in two orthogonal axes is provided for sequentially exposing a shot area on a photosensitive substrate. Sometimes, when the error between the target position and the current position, which is the output value of the interferometer that measures the position of the stage, is within a predetermined value for a predetermined time or more, it is determined that the positioning is complete, and immediately after that, exposure was performed. . However, in the conventional stepper described above, since the vibration amount of the stage during exposure is not monitored after the positioning of the substrate stage is completed, an abnormality in the stage control system or other parts in the apparatus during exposure is not performed. A stage displacement or the like occurs during exposure due to an operation or a disturbance such as vibration from the outside, so that a photosensitive substrate (device) having an exposure failure has an inconvenience of proceeding to the next step as it is.

The present invention has been made in view of the disadvantages of the prior art, and an object of the present invention is to prevent a photosensitive substrate having an exposure defect from proceeding to the next processing step. An object of the present invention is to provide an exposure apparatus which can be avoided in advance.

Another object of the present invention is to provide an exposure method capable of preventing a photosensitive substrate having an exposure failure from proceeding to the next processing step in advance.

[0007]

According to the first aspect of the present invention, an image of a pattern formed on a mask (R) is projected on a projection optical system (P) while a photosensitive substrate is positioned at a predetermined exposure position.
L) an exposure system for projecting and exposing the photosensitive substrate (52) onto the photosensitive substrate (52), the illumination system (40) illuminating the mask (R); and holding means (11) for holding the mask.
A projection optical system (PL) for projecting the pattern of the mask onto an imaging surface; and a substrate stage that holds the photosensitive substrate on the imaging surface and moves in a plane perpendicular to the optical axis of the projection optical system. (64); position measuring means (56) for measuring the position of the substrate stage; and stage control means (76-1) for positioning the substrate stage at an exposure position based on a target position and an output of the position measuring means. After the positioning of the substrate stage is completed, illumination system control means (76-1) which starts irradiating the mask with illumination light from the illumination system and ends after a predetermined time; and During the exposure from the start to the end of the irradiation of the illumination light, the position coordinates of the substrate stage are sequentially monitored via the position measuring means (56), and based on the monitoring result. And determine whether the deviation between the target coordinates and the current position coordinates at the time of exposure is within an allowable range,
An abnormality determining means (76-1) for issuing an abnormality signal when the value is outside the allowable range.

According to this, when a target position command is given to the stage control means at the start of exposure, the stage control means positions the substrate stage at the exposure position based on the target position and the output of the position measurement means. I do. After the completion of the positioning, the illumination system control means starts irradiating the mask with illumination light from the illumination system.
The pattern of the mask is projected and exposed on a photosensitive substrate via a projection optical system. Then, after a predetermined time, the exposure ends.
During this exposure, the abnormality determination means sequentially monitors the position coordinates of the substrate stage via the position measurement means,
Based on the monitoring result, it is determined whether or not the deviation between the target coordinates and the current position coordinates at the time of exposure is within an allowable range. If the deviation is outside the allowable range, an abnormal signal is issued. Therefore, when the position deviation of the substrate stage during exposure from the target position exceeds the allowable range due to an abnormality of the stage control means or some disturbance, the abnormality determination means makes an abnormality determination and issues an abnormality signal. Therefore, it is possible to stop the apparatus urgently based on this abnormal signal and quickly remove the photosensitive substrate on which the exposure failure has occurred due to the positional error of the substrate stage. In addition, the apparatus may be repaired and adjusted while removing the photosensitive substrate having the exposure failure.

In this case, the abnormality determining means (76-
In 1), for example, a simple average (arithmetic mean) value of the position deviation, a difference between the maximum position deviation and the minimum position deviation, or an arithmetic mean of the square of the deviation for each of the position data acquired at predetermined sampling time intervals. It may be determined whether or not the position deviation has exceeded the allowable range based on the square root of.

In this case, the determination of the abnormality by the abnormality determining means may be performed after the end of the exposure. In this case as well, the emergency stop of the apparatus and the replacement of the photosensitive substrate based on the abnormality signal can be performed. As in the invention described in Item 2, the control of the start / stop of irradiation of the illumination light to the mask (R) by the illumination system control means (76-1) is performed by opening and closing a shutter (16) provided in the illumination system (40). Then, the abnormality determination means (76-1) may terminate the abnormality determination from the start of closing of the shutter to the end of closing. With this configuration, the abnormality determination is performed by the abnormality determination unit during the period from the start to the closing of the shutter. Therefore, the abnormality determination is completed when the exposure is completed, and the abnormality determination is performed after the shutter is closed. It is possible to improve the throughput as compared with the case.

Here, the shutter is a typical example of an optical path opening / closing means that requires a certain time from the start of closing to the end of closing.
The concept includes a movable blind and the like as long as it has the same function.

In this case, there is no particular problem if the abnormality determination means starts the abnormality determination operation based on a shutter closing start signal from the illumination system control means.
As described above, an optical sensor (38) for detecting the amount of illumination light when the shutter (16) is open is further provided, and the abnormality determining means monitors the position coordinates of the substrate stage based on the output of the optical sensor. May be terminated to execute the abnormality determination. With this configuration, when the exposure is started and the shutter is opened, the light amount of the illumination light at that time is detected by the optical sensor, and the abnormality determining means determines the position of the substrate stage based on the output of the optical sensor. The coordinate monitoring is terminated, and the abnormality is determined. For example, the abnormality determining means monitors the position coordinates of the stage from when the amount of light detected by the optical sensor exceeds a certain value to when it falls again, and after it falls below a certain value, an abnormality is determined based on the monitoring result. May be performed. Also in this case, before the shutter is completely closed by the illumination system control means, the determination means makes an abnormality determination based on the monitoring result, so that the processing capacity (throughput)
Can be suppressed.

In any of the above cases, as described above, it is possible to immediately stop the apparatus when an abnormal signal is issued by the determination means, but depending on the use conditions or the user, In some cases, it is desired to replace only the photosensitive substrate and continue exposure without stopping the apparatus.

In such a case, the transport means (54, 54) for transporting the photosensitive substrate (52) may be configured as described above.
76-2) and a transfer control means (74) for exchanging the substrate via the transfer means based on the abnormality signal. With this configuration, when an abnormality is determined by the determination unit and an abnormality signal is issued, the transfer control unit replaces the substrate via the transfer unit based on the abnormality signal. Therefore, the exposure of the next substrate is continued without stopping the apparatus. Here, some history may be left for the board that has been exchanged and ejected (rejected) out of the apparatus so that the operator can confirm (recognize) it later.

According to a fifth aspect of the present invention, there is provided an exposure method for projecting and exposing a pattern image formed on a mask onto the photosensitive substrate via a projection optical system while the photosensitive substrate is positioned at a predetermined exposure position. A step of sequentially monitoring the position coordinates of the photosensitive substrate from the start of exposure to the end of exposure after the completion of the determination of the photosensitive substrate; and a target at the time of exposure based on the monitoring result in the first step. Determines whether the deviation between the coordinates and the current position coordinates is within the allowable range, and if it is outside the allowable range, determines that it is abnormal and issues a warning, or replaces the photosensitive substrate currently being exposed with another substrate And a second step.

According to this, at the start of exposure, the substrate stage is positioned at the exposure position, and after this positioning is completed, the mask pattern is projected and exposed on the photosensitive substrate via the projection optical system. During the period from the start of the exposure to the end of the exposure, the position coordinates of the photosensitive substrate are sequentially monitored. And
Based on the monitor result, it is determined whether or not the deviation between the target coordinates and the current position coordinates at the time of exposure is within an allowable range. If the deviation is out of the allowable range, it is determined that an error has occurred, and a warning is issued, or The photosensitive substrate being exposed is replaced with another substrate. Therefore, when the exposure process is stopped or the photosensitive substrate is replaced based on the abnormality warning, the exposure process can be continued.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

<< First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows the entire configuration of an exposure apparatus 10 according to the first embodiment. The exposure apparatus 10 is a so-called step-and-repeat type reduction projection type exposure apparatus (so-called stepper). The exposure apparatus 10 includes an illumination system 40, a reticle holder 11 as a holding unit, a projection optical system PL, a stage device 50, a control system, and the like.

The illumination system 40 includes a mercury lamp 12, an elliptical mirror 1
4. Rotary shutter 1 which is a kind of optical path opening / closing means
6, a mirror 18, an input lens 20, a fly-eye lens system 22, a beam splitter 24, a lens system 26, a reticle blind 28, a lens system 30, a mirror 32, and a main condenser lens 34. Here, each component of the illumination system will be described in detail together with its operation.

The illumination light for exposure from the mercury lamp 12 is condensed by the elliptical mirror 14 at its second focal point. In the vicinity of the second focal point, a rotary shutter (hereinafter, appropriately referred to as “shutter”) 16 that switches between blocking and transmission of illumination light by a motor 36 is disposed. When the shutter 16 is in an “open” state, the shutter is closed. The illumination light beam passing through the portion is reflected by the mirror 18 and enters the fly-eye lens system 22 via the input lens 20.

The fly-eye lens system 22 is for preventing illuminance unevenness within the exposure range of the illumination light. A large number of secondary light source images are formed on the exit side of the fly-eye lens system 22. Illumination light from each secondary light source image enters a lens system (condenser lens) 26 via a beam splitter 24.

At the rear focal plane of the lens system 26, a reticle blind 28 having an opening of a predetermined shape is arranged. The shape of this opening is set so as to be included in the circular image field IF of the projection optical system PL.

The illumination light that has passed through the lens system 26 has a uniform illuminance distribution at the position of the reticle blind 28, and this illumination light then passes through the opening of the reticle blind 28, and passes through the lens system 30, the mirror 32, And the condenser lens 34 via the main condenser lens 34
Irradiate a reticle R as a mask disposed between the reticle R and the projection optical system PL. Thus, an image of the opening of the reticle blind 28 is formed on the pattern surface on the lower surface of the reticle R.

In this embodiment, the beam splitter 2 is disposed between the fly-eye lens system 22 and the lens system 26.
4 (this beam splitter 24 emits about 9
5% or more), and the light amount of a part of the illumination light beam extracted by the beam splitter 24 is changed to an integrator sensor 3 as an optical sensor.
8 to be detected. The detection signal of the integrator sensor 38 is transmitted to the stage controller 76-1.
Supplied to

The reticle holder 11 holds a reticle R as a mask in a plane perpendicular to the optical axis AX of the projection optical system PL via a vacuum chuck or the like (not shown). It is configured to be finely movable in an XY plane orthogonal to the axis AX. Here, the reticle holder 11 is positioned such that the center (reticle center) of the circuit pattern on the reticle R substantially coincides with the optical axis AX.

In the projection optical system PL, at least the image plane side is telecentric, for example, both-side telecentric.
It is composed of only a refraction element having a predetermined reduction ratio, for example, 1/5, or a combination of a refraction element and a reflection element. The optical axis AX of the projection optical system PL is set to a vertical axis (Z axis) direction. Therefore, when the reticle R is illuminated by the exposure illumination light from the illumination system 40, a 1/5 reduced image of the circuit pattern is formed on the image forming plane via the projection optical system PL.

The stage device 50 includes a Y stage 48Y movable on a base (not shown) in a Y-axis direction (a direction perpendicular to the plane of FIG. 1) in a horizontal plane perpendicular to the optical axis AX.
An X stage 48 movable on the Y stage 48Y in an X axis direction orthogonal to the Y axis (a direction parallel to the plane of FIG. 1).
X and a Z stage 64 as a substrate stage mounted on the X stage and capable of finely moving in the optical axis AX direction (Z axis direction) of the projection optical system PL. These three stages 48Y, 48X, 64 are driven by a drive system 58.

At one end of the upper surface of the Z stage 64, a movable mirror 62 is provided. The movable mirror 62 is opposed to the movable mirror 62, and a laser beam is projected on the movable mirror 62. A laser interferometer 56 as a position measuring means for measuring a position in the XY plane 64 is disposed.

Here, in practice, the movable mirror is provided with an X movable mirror having a reflecting surface orthogonal to the X axis and a Y movable mirror having a reflecting surface orthogonal to the Y axis. An X1-axis laser interferometer and an X2-axis laser interferometer for position measurement in the X-axis direction, and a Y-axis laser interferometer for position measurement in the Y-axis direction are provided. In FIG. , Laser interferometer 56 as a representative. Therefore, the X coordinate of the Z stage 64 is measured by averaging the measurement values of the X1-axis laser interferometer and the X2-axis laser interferometer, and X1
The yawing amount (the amount of rotation around the Z axis) is measured based on the difference between the measurement values of the X-axis laser interferometer and the X-axis laser interferometer, and the Y coordinate of the Z stage 64 is measured based on the measurement value of the Y-axis laser interferometer. In the following description, it is assumed that the XY coordinate position and the yawing amount of the Z stage 64 are measured by the laser interferometer 56. The output of the laser interferometer 56 is also supplied to the stage controller 76-1. The fixed mirror for the laser interferometer 56 is actually fixed to the lower end of the lens barrel of the projection optical system PL, but is not shown in FIG.

The photosensitive substrate 52 is held on the Z stage 64 via a θ table (not shown) and a substrate holder. The θ table is rotatable around the Z axis within a minute angle range by the drive system 58. That is, with the above-described configuration, the photosensitive substrate 52 is formed of X, Y, Z,
It is movable with four degrees of freedom in the θ (rotation around the Z axis) direction.

As described above, in this embodiment, since the projection magnification is set to 1/5, when the focused state (the state where the surface of the wafer W coincides with the imaging plane of the projection optical system PL) is formed on the reticle R. The image of the formed pattern is reduced to 1/5 by the projection optical system PL and formed on the wafer W.

A reference mark plate (not shown) on which various reference marks for reticle alignment, so-called baseline measurement, etc. are formed is also fixed on the Z stage 64.

In addition, although not shown, T for detecting an alignment mark on the photosensitive substrate 52 (or a mark on the reference mark plate) via the reticle R and the projection optical system PL.
A TR (through-the-reticle) type alignment system, and a TTL (through-the-lens) type that detects an alignment mark on the wafer W (or a mark on a reference mark plate) from the space below the reticle R via the projection optical system PL. An alignment system, a focus detection system, and the like are provided, and before the start of exposure of each shot of the step-and-repeat method, relative positioning between the reticle R and the photosensitive substrate 52, automatic focusing, and the like are performed.

The stage controller 76-1 is constituted by a so-called microcomputer comprising a processor, a ROM, a RAM, an I / O interface and the like.
The basic operation of the stage controller 76-1 is based on the input of position information and yawing information from the laser interferometer 56, etc., via the drive system 58 and the X stage 48X, Y stage.
The stage 48Y is controlled to position the photosensitive substrate 52 at the time of exposure, or the Z stage 64 is controlled via a drive system based on information from a focus detection system (not shown) to position the photosensitive substrate 52 at the image plane position. In other words, the shutter 16 is opened and closed by controlling the motor 36 in response to a command from a host computer 74 described later. The specific control operation of the stage controller 76-1 will be described later in further detail.

Further, in this embodiment, a transfer arm 54 for loading, unloading and transferring the photosensitive substrate 52 is provided, and the transfer arm 54 is controlled by a transfer system controller 76-2 described later.

FIG. 2 shows a main configuration of a control system of the entire exposure apparatus 10. This control system includes a host computer (master processor) 74 for managing the flow of jobs of the entire apparatus, and a plurality of controllers 76-1, 76-2,... Under the control of the host computer 74.
.., 76-m.

Here, the host computer 74 is constituted by a so-called mini computer. The stage controller 76-1 includes a slave processor (hereinafter, “SP”) under the control of the host computer 74.
78-1), a stage control function processor (hereinafter referred to as "stage control FP") 80-1 under the control of the SP 78-1, and an exposure control function processor (hereinafter referred to as "exposure control FP") 80-. 2 and so on. This stage controller 7
In addition to 6-1, various control devices 76-3,..., 76-m such as a transport system controller 76-2, an illumination system controller, a lens controller, and an alignment controller are provided. Controllers 76-1, 76-2, ..., 7
6-m is actually stored as a control board in a rack (not shown) in which the host computer 74 is stored.

Next, the operation of this control system during exposure will be described. FIG. 3 is a flowchart showing the control algorithm of SP78-1, and FIG. 4 is a flowchart showing the control algorithm of stage control FP80-1.

The flowchart in FIG. 3 starts when an exposure sequence execution command is input from the host computer 74. First, step 10
In step 2, the SP 78-1 outputs the position command value to the stage FP together with the command of "moving the stage to the designated position", and then waits for the stage control FP 80-1 to notify the end of the movement (step 104).

Along with the command of "moving the stage to the designated position", the position command value is changed to the stage control FP80-1.
Is started, the flowchart of FIG. 4 starts. Here, a case where the X stage 48X is moved will be described as an example.

First, the stage control FP 80-1 moves the stage in steps 202 to 204, and waits for completion of positioning. Specifically, the X stage 48X is servo-controlled via the drive system 58 based on the position deviation which is the difference between the position command value and the current value output from the laser interferometer 56. The determination of the completion of the positioning is made based on whether or not the position deviation has fallen within a predetermined range for a predetermined time or more, similarly to a known method.

When the positioning is completed, the stage control FP80-1 proceeds to step 206 to notify "end of movement" to the SP 78-1, and then proceeds to step 208 to confirm that there is an instruction to start the displacement monitoring. wait.

On the other hand, in SP78-1, upon receiving the above-mentioned "movement end" notification, the flow advances to step 106 to send a "shutter 16 opening / closing command for a designated time" to the exposure control FP 80-2, After sending the command of “start of displacement monitoring” to the control FP 80-1, the process proceeds to step 108 and waits for the closing of the shutter 16 to be completed.

As a result, the motor 36 is controlled by the exposure control FP80-2, and the shutter 16 starts to open. After the shutter 16 is completely opened, the exposure control FP80-2 opens the shutter 16 for a designated exposure time and then closes the shutter 16.

On the other hand, the stage control FP80-1 receives the command of "start of position shift monitoring", and proceeds to step 210 to start position shift monitoring almost simultaneously with the start of "opening" of the shutter 16. Specifically, a position deviation (position deviation amount), which is a difference between a measured value of the laser interferometer and a target value, is sampled at intervals of a predetermined sampling time (for example, 1 mmsec).

After the start of the displacement monitoring, the stage control FP80-1 continues to monitor the displacement until there is an instruction of "end of the displacement monitoring" (steps 210 and 21).
2). As a result, the position shift monitoring during exposure of a certain shot area on the photosensitive substrate 52 is continued.

In the exposure control FP80-2, when the exposure is completed and the shutter 16 is completely closed, the shutter "closed" is notified to the SP 78-1. In SP78-1, in response to this, the process proceeds to step 110 to send a command of “end, analysis, and determination of position deviation monitoring” to the stage control FP80-1, and then proceeds to step 112 to execute the stage control FP8.
Wait for the result of analysis from 0-1.

On the other hand, the stage control FP80-1 receives the above-mentioned "end of position deviation monitor, analysis and judgment" command,
After the displacement monitor is completed, the process proceeds to step 214, where the monitor result is analyzed and the presence or absence of an abnormality is determined. In particular,
By determining whether or not the arithmetic mean of each sampled positional deviation amount exceeds a specified value, the deviation of the exposure center can be determined, or the difference between the maximum value and the minimum value of each sampled positional deviation amount (peak-to-peak) can be determined. The variation of the exposure line width is determined by determining whether the average value of the peak value or the absolute value exceeds a specified value. Alternatively, the vibrations of the X stage 48X, the Y stage 48Y, and the Z stage 64 may be evaluated to some extent quantitatively based on the square root of the arithmetic mean of the squares of the sampled positional shift amounts.

When the analysis of the monitor result and the determination of the abnormality are completed in this way, the stage control FP80-1
Then, in step 216, the analysis result (judgment result) is set to S
After notifying P78-1, the series of processing of this routine ends.

On the other hand, SP78-1 receives this notification,
After notifying the host computer 74 of the result of the abnormality determination together with the notification of “exposure sequence end”, a series of processing of this routine is ended.

FIG. 5 is a flowchart showing the above operation.

If the result of the exposure end is abnormal, the host computer 74 notifies the operator of the error and stops the apparatus. Alternatively, when the result of the exposure end is abnormal, the host computer 74 aborts the exposure sequence of the photosensitive substrate 52 currently held by a substrate holder (not shown) on the Z stage 64 and sends the sequence through the transport system controller 76-2. By controlling the transfer arm 54 and a photosensitive substrate exchange mechanism (not shown), the photosensitive substrate 52 may be exchanged for another photosensitive substrate, and the process may be shifted to the exposure of the photosensitive substrate. In the latter case, it is desirable to leave some history so that the operator can confirm the photosensitive substrate 52 discharged (rejected) out of the apparatus by replacement. As a specific method of how to retain the history, for example, it is displayed on a display screen (not shown) connected to the host computer 74 whether or not all the photosensitive substrates in one lot have been rejected halfway. Is mentioned.

It is desirable that the operator be notified of the error and that the apparatus be stopped or the photosensitive substrate be replaced to continue the exposure processing by setting a mode in advance so that the operator can select it. It is considered that some operators (users) do not want to stop the apparatus when a slight exposure defect occurs, and may want to immediately execute maintenance and inspection of the apparatus when any exposure defect occurs. This is because it is expected to meet the requirements of any operator.

As is clear from the above description,
In the first embodiment, the stage controller 76-1 constitutes a stage control unit, an illumination system control unit, and an abnormality determination unit. Specifically, the stage control FP80
The stage control means and the abnormality determination means are constituted by -1 and the illumination system control means is constituted by the exposure control FP80-2. In addition, a transport unit is configured by the transport arm 54, the transport system controller 76-2, and the photosensitive substrate exchange mechanism (not shown), and a transport control unit is configured by the host computer 74.

As described above, according to the exposure apparatus 10 of the first embodiment, in the step SP78-1, which manages the sequence of the stage control and the shutter control for the exposure, the stage control FP80-1 is exposed. The start and end are notified, and the status control FP80-1 starts to
The difference between the target value and the current value of the coordinates of the X stage 48X and the Y stage 48Y (movable stage) during the end is sampled at a predetermined time interval, and the value sampled at the end is represented by a peak-to-peak or average value. It is determined whether or not there is an abnormality. If there is an abnormality, the host computer 74 is notified via the SP 78-1. The host computer 74 interrupts and stops the exposure sequence based on the notification of the abnormality, or rejects the photosensitive substrate 52, and continues the process for loading the next photosensitive substrate and exposing.

Therefore, according to the exposure apparatus 10 of the present embodiment, it is possible to prevent the photosensitive substrate 52 (defective device) of the exposure failure from proceeding to the next step. In addition, the device can be repaired or adjusted based on the error notification described above.

In the first embodiment, the exposure control FP8
The actual exposure time is the time required for the analysis of the sampling data of stage FP80-1 and the determination of an abnormality to be performed after the completion notification from 0-2, and the time required for the SP-FP interface required for performing these. In addition to this, it is conceivable that the processing capacity (throughput) is reduced. That is, in the step-and-repeat type exposure apparatus, if the number of exposures per photosensitive substrate is large (the number of shots is large), this influence may not be negligible.

Therefore, the following second embodiment has been made in order to improve (do not unnecessarily lower) the throughput.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS.
The exposure apparatus of the second embodiment differs from the above-described first embodiment only in the functions of the processors (SP, FP) constituting the stage controller, and the configuration of the other parts is the same. Here, only this point will be described.

FIG. 6 is a flowchart showing the control algorithm of the SP 78-1, and FIG. 7 is a flowchart showing the control algorithm of the stage control FP 80-1.

The flowchart in FIG. 6 starts when an exposure sequence execution command is input from the host computer 74.

In steps 302 to 306, SP
78-1 is Step 10 in the first embodiment described above.
The same processing and judgment as in Steps 2 to 106 are performed, and in Step 308, the process waits until the exposure control FP 80-2 notifies the shutter start closing status.

On the other hand, similarly to the first embodiment, when the position command value is input together with the command of “moving the stage to the designated position” from the SP 78-1, the stage control FP80-1 receives the position shown in FIG. The operation of the control algorithm is started, and in steps 402 to 408, the same processing and processing as steps 202 to 208 in the first embodiment described above are performed.
The determination is made, and the position deviation monitoring is continued until there is an instruction of the position deviation “monitor end” in steps 410 and 412. That is, the monitoring of the displacement during exposure of a certain shot area on the photosensitive substrate 52 is being continued.

In exposure control FP80-2, step 306
The shutter 16 is opened for a predetermined time in accordance with the "command for opening / closing the shutter for a specified time" from SP78-1 in step S7, and the exposure is performed. When the specified exposure time has almost elapsed, the motor 36 is controlled. At the same time as starting the "close" control of the shutter 16, the status of the start of the "close" of the shutter is notified to the SP 78-1.

In SP78-1, this is received, and step 3
Proceeding to 10, the command of "end of position deviation monitoring, analysis and judgment" is sent to the stage control FP80-1, and then the process proceeds to step 312 to wait for the stage control FP80-1 to notify the analysis result.

On the other hand, in response to this command, the stage control FP80-1 proceeds to step 413 and waits for a predetermined time (a predetermined waiting time) to elapse. After the elapse of the waiting time, the position deviation monitor (sampling) ends. Proceeding to step 414, the analysis of the monitoring result and the presence or absence of an abnormality are determined. This specific method is the same as in the first embodiment.

When the analysis of the monitor result and the judgment of the abnormality are completed in this way, the stage control FP80-1
Then, in step 416, the analysis result (judgment result) is set to S
After notifying P78-1, the series of processing of this routine ends.

On the other hand, at SP78-1, upon receiving this notification, the flow advances to step 313 to wait for notification of the end of the shutter "close" from the exposure control FP80-2, and a predetermined time, for example, 40 mmsec, has elapsed since the start of the shutter "close". Then, when the shutter “close” end is notified from the exposure control SP 78-1,
After notifying the host computer 74 of the result of the abnormality determination together with the notification of “exposure sequence end”, a series of processing of this routine is ended.

FIG. 8 is a flowchart showing the above operation.

When the result of the completion of the exposure is abnormal, the host computer 74 notifies the operator of the error and stops the apparatus, or stops the current Z, as in the first embodiment.
The exposure sequence of the photosensitive substrate 52 held by a substrate holder (not shown) on the stage 64 is terminated, the photosensitive substrate 52 is replaced with another photosensitive substrate, and the process shifts to exposure of the photosensitive substrate.

As described above, according to the second embodiment, the exposure control FP80-2 performs
The status of “start” is given to SP78-1 at the same time as the shutter closing operation starts, and SP78-1
A command is issued to the stage control FP80-1 to stop sampling, analyze sampling data, and judge abnormalities. In this case, the exposure of the photosensitive substrate 52 is continued from the start to the end of the closing of the shutter 16, but since the exposure power decreases with the start of the closing of the shutter 16, the exposure of the shutter 16 is reduced to a certain level. It is considered that if the closing operation is advanced, the influence of the position shift of the stage on the exposure of the photosensitive substrate 52 is small.
0-1 waits for a certain time (step 413),
Sampling was stopped, the sampled data was analyzed, and abnormalities were determined.

According to the present embodiment, in addition to the same effects as those of the above-described first embodiment, the analysis of sampling data of the stage control FP80-1 and the detection of abnormalities are performed before the exposure is completed (shutter is closed). Since the determination has been completed (see FIG. 8), there is an effect that the processing capacity (throughput) can be improved as compared with the first embodiment. Specifically, for example, in the case of a liquid crystal stepper, 500 shots per one shot area on the photosensitive substrate 52.
Assuming that an exposure time of mmsec is required, a time reduction of about 30 mmsec is possible. In particular, step and
In a repeat type exposure apparatus, the effect of improving the throughput increases as the number of exposures per photosensitive substrate increases.

If the time required to “close” the shutter 16 is sufficiently short, the interface time at which the SP 78-1 issues a command to the stage control FP 80-1 in step 310 may correspond to the waiting time. In such a case, step 413 of the above flowchart may be omitted.

As another method of performing the analysis and determining the abnormality before the shutter closing operation by the exposure control FP80-2 is completed, the exposure control FP80-2 uses the integrator sensor 38 which is originally used for controlling the integrated exposure amount. Control F
P80-1 sequentially monitors, and performs the above-described sampling (positional deviation monitor) from the time when the amount of light received by the sensor 38 exceeds a certain level until it falls again, and after the fall, analyzes the data and judges the abnormality. There is a way to do it. In this method, too, the analysis and the determination of the abnormality are performed before the shutter closing operation by the exposure control FP80-2 ends, so that it is possible to maintain the same high throughput as in the second embodiment. This can be easily realized by changing the control software of each processor in the stage controller 76-1. In this case,
The stage control FP80-1 may notify this result at the time of the next instruction from SP78-1.

In the first and second embodiments, the case where the shutter 16 is used as the optical path opening / closing means has been described. However, instead of the reticle blind 28 in FIG. 1, a so-called movable blind comprising a plurality of movable blades is used. When this is used, the movable blind may be used as an optical path opening / closing means.

[0076]

As described above, according to the first aspect of the present invention, it is possible to prevent a photosensitive substrate having an exposure failure from proceeding to the next processing step in advance. Has an effect.

According to the second and third aspects of the present invention, in addition to the effects of the first aspect of the invention, there is an effect that the processing capacity can be improved.

According to the invention described in claim 4, in addition to the effects of the invention described in each of the above-mentioned claims, an effect that exposure of the next substrate can be continued without stopping the apparatus. There is.

According to the fifth aspect of the present invention, it is possible to prevent the photosensitive substrate having the exposure failure from proceeding to the next processing step in advance, and to replace the photosensitive substrate when exchanging the photosensitive substrate. There is an effect that exposure can be continued for the substrate.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of an exposure apparatus according to a first embodiment.

FIG. 2 is a block diagram showing a configuration of a control system of the entire apparatus of FIG.

FIG. 3 is a flowchart showing a control algorithm of an SP in the stage controller of FIG. 2;

FIG. 4 is a flowchart illustrating a control algorithm of a stage control FP of FIG. 2;

FIG. 5 is a diagram showing a flow of an operation of a control system according to the first embodiment.

FIG. 6 is a flowchart illustrating a control algorithm of an SP in a stage controller according to a second embodiment.

FIG. 7 is a flowchart illustrating a control algorithm of a stage control FP according to a second embodiment.

FIG. 8 is a diagram showing a flow of an operation of a control system according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 exposure apparatus 11 reticle holder 16 shutter 38 integrator sensor 40 illumination system 52 photosensitive substrate 54 transfer arm 56 laser interferometer 64 Z stage 74 host computer 76-1 stage controller 76-2 transfer system controller 80-1 stage control FP 80-2 Exposure control FPR reticle PL Projection optical system

Claims (5)

[Claims] 1. An exposure apparatus for projecting and exposing an image of a pattern formed on a mask onto a photosensitive substrate via a projection optical system with the photosensitive substrate positioned at a predetermined exposure position, wherein the mask is illuminated. An illumination system for holding; a holding unit for holding the mask; a projection optical system for projecting the pattern of the mask onto an image plane; and an optical axis of the projection optical system for holding the photosensitive substrate at the image plane position. A stage moving in a plane perpendicular to the plane; position measuring means for measuring the position of the substrate stage; and stage control means for positioning the substrate stage at an exposure position based on a target position and an output of the position measuring means. Illumination system control means for starting irradiation of illumination light from the illumination system to the mask after completion of positioning of the substrate stage and ending after a predetermined time; During the exposure from the start to the end of the irradiation of the illumination light to the mask, while sequentially monitoring the position coordinates of the substrate stage via the position measuring means, based on the monitoring result, the target coordinates at the time of exposure and An exposure apparatus that determines whether a deviation from the current position coordinates is within an allowable range and issues an abnormal signal when the deviation is out of the allowable range. 2. The control of starting / stopping irradiation of the mask with the illumination light by the illumination system control means is performed by opening and closing a shutter provided in the illumination system. The exposure apparatus according to claim 1, wherein the abnormality determination is ended from to when the closing is completed. 3. An optical sensor for detecting a light amount of the illumination light in an open state of the shutter, wherein the abnormality determining means ends monitoring of position coordinates of the substrate stage based on an output of the optical sensor. The exposure apparatus according to claim 2, wherein the abnormality determination is performed by performing the determination. 4. The apparatus according to claim 1, further comprising: transport means for transporting said photosensitive substrate; and transport control means for exchanging said substrate via said transport means based on said abnormality signal. The exposure apparatus according to claim 1. 5. An exposure method for projecting an image of a pattern formed on a mask onto a photosensitive substrate via a projection optical system while positioning the photosensitive substrate at a predetermined exposure position, the exposure method comprising: After the completion of the determination, the first coordinate for sequentially monitoring the position coordinates of the photosensitive substrate between the start of exposure and the end of exposure.
Determining whether or not the deviation between the target coordinates and the current position coordinates at the time of exposure is within an allowable range based on the monitoring result in the first step, and determining that there is an abnormality when the deviation is outside the allowable range. Issuing a warning or replacing the photosensitive substrate currently being exposed with another photosensitive substrate.