JP2009170733A - Exposure apparatus, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure apparatus keeping stable exposure performance by restraining vibration generated by positioning an original plate stage and a substrate stage from being transmitted to a projection optical system, and reducing influence of change with time of the shape of a floor. <P>SOLUTION: In this exposure apparatus, an original plate is illuminated through an illumination optical system by exposure light from a light source, and a pattern formed on the original plate is projected and exposed to a substrate through the projection optical system. The exposure apparatus includes: the original plate stage for mounting the original plate thereon; a first structure supporting the illumination optical system and the original plate stage; and a first position adjustment mechanism adjusting the position of the original plate stage between the first structure and the floor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exposure apparatus that projects and exposes a circuit pattern of an original on a substrate.

A semiconductor exposure apparatus that projects and exposes a circuit pattern of an original onto a substrate needs to be exposed by superimposing a pattern in the next process on the pattern exposed in the previous process.
Further, in order to accurately form an image, it is necessary to accurately match the original plate with the object plane of the projection optical system and the substrate with the image plane position of the projection optical system.
For this alignment, the original is mounted on an original stage having an alignment mechanism, and the substrate is mounted on a substrate stage having an alignment mechanism.
However, the driving stroke of the original stage and the substrate stage is also limited by the size of the apparatus.
For this reason, if the positions of the original stage and the substrate stage are greatly deviated from the projection optical system, the original and the substrate cannot be adjusted to predetermined positions by stage driving.

In the conventional semiconductor exposure apparatus, the structure on which the original stage and the projection optical system are mounted is the same structure, and the substrate stage also supports the surface plate on which the original stage and the projection optical system are mounted. It was mounted on.
For this reason, for example, even when the floor surface is in a different state due to aging and the height partially changes, the positional relationship between the original stage, the substrate stage, and the projection optical system is kept constant. There was no particular inconvenience.
However, the alignment process of the original stage for aligning the original with the object plane of the projection optical system at the time of assembling the exposure apparatus requires a high degree of accuracy, so that much time has conventionally been spent for adjustment.
Further, in Japanese Patent Laid-Open No. 2006-49644 (Patent Document 1), a stage control unit that controls driving of a substrate stage that positions a substrate with respect to an original plate changes control parameters of the substrate stage based on immersion conditions. An immersion exposure apparatus has been proposed.
JP 2006-49644 A

In recent years, with the higher integration of semiconductor elements, the resolving power required for a semiconductor exposure apparatus has become higher, the projection optical system has an aperture ratio (NA) of 0.9 or more, and the projection lens has increased in size (objects). The increase in the length between the surface and the image surface and the increase in the diameter are progressing.
For this reason, the sensitivity to the deterioration of the resolution performance due to the vibration of the lens in the lens support structure of one projection optical system is increased, which affects the miniaturization.
On the other hand, in order to improve production efficiency, it is required to improve the number of substrates that can be processed in a fixed time, that is, throughput.
In the current semiconductor exposure apparatus, a so-called scan exposure method in which the pattern of the original is exposed onto the substrate while the original and the substrate are driven in synchronization is the mainstream.
In order to improve the throughput, it is effective to improve the driving speed of the original stage and the substrate stage, so that the speed of the original stage and the substrate stage has been increased.
A counter mass for canceling the reaction force when driving both the original stage and the substrate stage is arranged.
However, 100% reaction force cannot be canceled by this counter mass due to the influence of parts accuracy.
As the stage speed increases, the acceleration increases, and the reaction force increases accordingly, and the leakage reaction force that cannot be erased by the counter mass increases accordingly.
When the reaction force propagates through the structure and enters the projection optical system, the resolution performance deteriorates, and not only the resolution performance but also the image of the projection optical system fluctuates due to vibration, thereby causing an image position shift.

As described above, since the sensitivity of the projection optical system to vibration has increased in recent years, it is greatly affected by vibration.
In order to prevent this, in recent years, a configuration has been adopted in which a unit that can be a vibration source such as an original stage or a substrate stage is supported by a separate structure from the projection optical system.
With this configuration, the vibrations of the original stage and the substrate stage are not directly transmitted to the projection optical system, and if they are transmitted, they are transmitted through the floor supporting both structures.
However, the amount of vibration transmission is extremely small compared to the case where the stage and the projection optical system are mounted on the same structure.
As described above, in terms of vibration transmission, a configuration in which the original stage, the substrate stage, and the projection optical system are independently supported is extremely advantageous.
However, this is extremely disadvantageous from the viewpoint of alignment of the original plate, the substrate stage and the projection optical system.
When both are mounted on the same structure, even if the floor shape changes over time after the exposure apparatus is installed, the original stage mounted on the same structure, the projection optical system, the illumination optical system, and the substrate stage The positional relationship between the projection optical system and the projection optical system was kept constant.
However, in the case of this independent support structure, since the support structures are installed at different locations on the floor, the plane shape of the floor changes with time, so that the attitude of the projection optical system, the original, and the substrate stage are respectively Change in different directions and amounts. As a result, each positional relationship changes.
Although there is no problem if the original stage and the substrate stage have sufficient drive strokes that can absorb the change over time, it is usually difficult to ensure such a large stroke.

In addition, the illumination optical system mounted on the same structure as the original stage is a unit that originally does not have a positioning drive mechanism, so the positional deviation from the projection optical system is directly related to the deterioration of the telecentricity, and the exposure image The shift of the image occurs due to the displacement of the substrate in the focus direction with respect to the surface. For this reason, accurate pattern overlay exposure becomes difficult.
In addition, a TTR microscope, which is a scope for observing an image plane through a projection optical system, may be mounted on the same structure as the original stage. In this case as well, the position shift of the TTR microscope may be an observation mark shift or observation. The mark may not enter the measurement field of view.
Therefore, the present invention reduces exposure of vibration due to alignment of the original stage and the substrate stage to the projection optical system, reduces the influence of changes in the floor shape over time, and maintains stable exposure performance. An object is to provide an apparatus.

   In order to achieve the above object, an exposure apparatus of the present invention illuminates an original via an illumination optical system with exposure light from a light source, and projects and exposes a pattern formed on the original onto a substrate via a projection optical system. An exposure apparatus comprising: an original stage on which the original is mounted; a first structure that supports the illumination optical system and the original stage; and a position of the original stage between the first structure and the floor And a first position adjusting mechanism for adjusting.

   According to the present invention, it is possible to reduce the vibration caused by the alignment of the original stage and the substrate stage from being transmitted to the projection optical system, to reduce the influence of the temporal change in the shape of the floor, and to maintain stable exposure performance.

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

With reference to the schematic block diagram of FIG. 1, the exposure apparatus of Example 1 of this invention is demonstrated.
The original 1 is illuminated through the illumination optical system 9 with exposure light from a light source (not shown).
Further, the exposure apparatus projects and exposes the pattern formed on the original 1 onto the substrate 14 via the projection optical system 13.
The original 1 is one on which a semiconductor circuit pattern is drawn. The original stage 2 is a stage on which the original 1 is mounted and held.
A laser is applied to the bar mirror BM1 provided on the original stage 2 by the laser interferometer 4 held on the meter measuring board 3, and the original stage 2 is caused by the interference between the reference light and the reflected light of the laser interferometer 4 itself. The position is measured.
By arranging a plurality of laser interferometers 4, the X, Y, Z directions and the ωx, ωy, ωz directions are measured, and based on these measured values, the original stage 2 can measure the X, Y, Z directions and ωx, ωy, ωz. Is driven and positioned.
The original stage 2 may be composed of a plurality of driving units such as a coarse moving part and a fine moving part, but in the present embodiment, it is simplified for the sake of simplicity of explanation.
The original stage 2 is supported by an original stage surface plate 7 which is a first structure. In addition, an illumination optical system 9 that illuminates the original 1 is mounted on the original stage surface plate 7.
The original stage surface plate 7 is supported by a base frame 6, and the base frame 6 is installed on the floor 8.
A master stage adjuster which is a first position adjusting mechanism comprising a drive unit for adjusting the position of the master stage 2 between the base frame 6 and the master stage surface plate 7, that is, a drive unit for adjusting the position of the master stage surface plate 7. 10 is interposed and mounted.
An inter-plate sensor 12 is provided for measuring the positional relationship between the original stage surface plate 7 and the lens barrel surface plate 6 in the 6-axis direction, and the original stage stage adjuster 10 is driven based on the measured value. Positioning.

The projection optical system 13 projects and exposes the semiconductor circuit pattern drawn on the original 1 onto the substrate 14 and is held by the lens barrel surface plate 11.
The lens barrel surface plate 11 and the meter measuring plate 3 are connected by a bending dosing mechanism (not shown), and the positional relationship between the two is always kept constant.
The laser interferometer 15 is a means for measuring the X, Y, Z directions and the ωx, ωy, and ωz directions between the vicinity of the original plate 1 of the projection optical system 13 and the meter measuring board 3.
The lens barrel mount 16 is positioned between the lens barrel surface plate 11 and the projection optical system 13, and the projection optical system 13 is moved in the X, Y, Z directions and ωx, ωy, ωz by an accelerometer signal or a displacement sensor (not shown). It is a means for vibration isolation and vibration suppression.
This prevents deformation and vibration of the lens barrel surface plate 11 from being transmitted to the projection optical system 13.
A lens barrel surface mount 17 is disposed between the base frame 5 and the lens barrel surface plate 11 in order to dampen and suppress vibration from the floor 8.
The mark position measuring microscope 18 is supported by the measuring board 3 and is a means for measuring the mark position drawn on the substrate 14.
The laser interferometer 19 is a means for measuring the X, Y, Z directions and the ωx, ωy, and ωz directions between the vicinity of the substrate 14 of the projection optical system 13 and the metering measurement panel 3.

The substrate 14 is mounted and held on the substrate stage 20.
A laser is applied to the bar mirror BM2 provided on the substrate stage 20 from the laser interferometer 21 attached to the meter measuring board 3, and the X, Y, Z directions and the ωx, ωy, and ωz directions of the substrate stage 20 are measured.
The substrate stage 20 is driven and positioned in the X, Y, and Z directions and in the ωx, ωy, and ωz directions by a calculation / control unit (not shown) based on the measured values.
Similar to the original stage 2, the substrate stage 20 may be constituted by a coarse movement part, a fine movement part, and the like, but in this embodiment, it is simplified for the sake of simplicity of explanation.
The substrate stage 20 is supported by a substrate stage surface plate 22 that is a second structure, and the substrate stage surface plate 22 is moved from the measuring plate 3 to the X, Y, Z directions and ωx, ωy, ωz by a sensor 23 between the surface plates. The distance between the surface plates in the direction is measured.
Similar to the original stage surface plate 7, the substrate stage surface plate 22 is also provided with a substrate stage adjuster 24, which is a second position adjusting mechanism comprising a drive unit capable of adjusting the position.
As a result, the substrate stage surface plate 22 and the measuring plate 3 are driven and adjusted based on the value of the surface plate sensor 23 so that the substrate stage surface plate 22 and the measuring plate 3 are in a fixed positional relationship.
The focus sensor 25 is a means for measuring the distance between the projection optical system 13 and the substrate 14 and is attached to the meter measuring board 3.
The measuring means for measuring the positional relationship between the projection optical system 13 and the original stage 2 or the substrate stage 20 is composed of a laser interferometer with an origin detection function such as an eddy current sensor or a capacitance sensor, and is a sensor for measuring an absolute position. is there.
Beams 26 a and 26 b are irradiated from the laser interferometers 4, 15, 19 and 21.

The substrate 14 is transferred to the substrate stage 20 by a substrate transfer device (not shown), and the mark position measuring microscope 18 observes the positioning marks exposed on the substrate 14 in the previous step.
Thus, the drawing position and arrangement of the semiconductor circuit pattern are obtained, and the substrate 14 is moved and arranged by the focus sensor 25 at the focal position of the projection optical system 13 by the substrate stage 20.
Thereafter, in accordance with the previously measured arrangement, the circuit pattern on the original 1 is exposed so as to accurately overlap the pattern printed in the previous step on the substrate 14 via the projection optical system 13.
For this reason, the pre-process while driving the substrate stage 20 in the X, Y, Z directions and the ωx, ωy, ωz directions based on the values calculated by the control unit (not shown) based on the measurement values of the laser interferometer 21 Repeat exposure for the number of patterns printed in step (b).
At this time, the amount of shaking of the projection optical system 13 is measured by the laser interferometers 15 and 19 on the original plate 1 side and the substrate 14 side, respectively, and this value is added to the driving amounts of the original plate stage 2 and the substrate stage 20. The image shift due to the shaking of the projection optical system 13 is eliminated.
After the exposure is completed, the substrate 14 is carried out of the exposure apparatus by the substrate transport device (not shown) from the substrate stage 20 and the exposure process is completed.

In recent exposure apparatuses such as the first embodiment, for the purpose of reducing the aberration performance guarantee area of the projection optical system 13, the original 1 and the substrate 14 are moved while being synchronized while using the limited exposure area. A scan exposure method in which one pattern is exposed on the substrate 14 is employed.
In the case of this scanning exposure method, since the original stage 2 and the substrate stage 20 are driven during exposure, the original stage 2 and the substrate stage 2 are each provided with a mechanism for erasing the reaction force generated at the time of driving. ing.
However, it is difficult to erase the reaction force entirely by these reaction force canceling mechanisms due to manufacturing errors and the like, and these reaction forces that cannot be erased leak. Therefore, the original stage 2 and the substrate stage 20 are driven to drive the vibration source. It becomes.
In the configuration of the first embodiment shown in FIG. 1, the lens barrel surface plate 11, the measuring plate 3, and the original stage 2 and the substrate stage 20 that are the vibration sources are separated from each other because the vibration is transmitted. The vibration is not transmitted directly.
For this reason, performance degradation of the projection optical system 13 due to vibration and measurement value fluctuations of the laser interferometers 4, 15, 19, and 21 due to vibration hardly occur, and high-precision positioning is performed while maintaining the performance of the projection optical system 13 stably. The resulting image can be exposed to the substrate 14.

However, another problem may occur only by separating the original stage 2 and the substrate stage 20 which are vibration sources.
The reference example of the present invention shown in FIG. 2 includes an original stage adjuster 10 that is a first position adjusting mechanism and a substrate stage adjuster 24 that is a second position adjusting mechanism of the first embodiment of the present invention shown in FIG. It is an exposure apparatus that does not have.
In the reference example of the present invention shown in FIG. 2, a state in which the surface of the floor 8 changes with time is schematically shown.
The same reference numerals as those of the first embodiment of the present invention shown in FIG.
In the case where the floor 8 undergoes a shape change due to the influence of the apparatus load or the like as in the reference example of the present invention shown in FIG. 2, and the degree of the shape change varies depending on the location, the projection optical system 13 and the original stage 2 The positional relationship between the illumination optical system 9 and the substrate stage 20 is shifted.
If the stage strokes of the original stage 2 and the substrate stage 20 are sufficiently secured, the above-described positional deviation can be corrected by the original stage 2 and the substrate stage 20.
However, the stage stroke is actually limited to some extent due to size restrictions and power consumption restrictions.
For this reason, the stage stroke cannot be corrected depending on the amount of change of the floor 8 with time.
On the other hand, since the illumination optical system 9 is also supported by the original stage surface plate 7 like the original stage 2, the optical axes of the projection optical system 13 and the illumination optical system 9 are shifted.
For this reason, the image formation amount of the projection optical system 13 is deteriorated, and the amount of image shift caused by the displacement of the substrate 14 with respect to the image plane of the projection optical system 13 increases, so that the image cannot be exposed at the correct position.
Therefore, in order to expose the image at the correct position, the original stage adjuster 10 and the substrate stage adjuster 24 are driven, and the positions between the projection optical system 13 and the original stage 2 and between the projection optical system 13 and the substrate stage 20. Keep the relationship change below a certain amount.

FIG. 3 schematically shows a state where the surface shape of the floor 8 of the first embodiment of the present invention shown in FIG. 1 changes over time.
As shown in FIG. 3, when the surface shape of the floor 8 changes with time, the displacement amount can be detected by the platen sensor 12 on the original plate 1 side and the platen sensor 23 on the substrate 14 side.
FIG. 3 shows a state in which the original stage adjuster 10 as the first position adjusting mechanism and the substrate stage adjuster 24 as the second position adjusting mechanism are driven so that the detected displacement amount disappears.
Although the floor 8 is deformed and the position of the base frame 6 is changed, the original stage adjuster 10 and the substrate stage adjuster 24 are driven six axes in a direction to absorb the change.
Thereby, the original stage surface plate 7 and the substrate stage surface plate 22 maintain a fixed positional relationship with respect to the projection optical system 13.
The drive is divided into manual and automatic, the speed of the surface shape change of the floor 8 is very slow, and if there are very few opportunities for position correction by both the original stage adjuster 10 and the substrate stage adjuster 24, both adjusters or One adjuster may be driven manually.
In this case, while observing the measurement values of the surface plate sensors 12 and 23, manual adjustment is performed at regular intervals or when the amount of deviation exceeds an allowable value so that the measurement value becomes the value at the time of installation of the apparatus.
The adjustment is performed with respect to the axis in which deviation occurs among the six axes of X, Y, Z, ωx, ωy, and ωz.
Moreover, it may be necessary to make adjustments when an irregular work other than an earthquake or a normal operation state is performed.
In the case of manual operation, it is necessary to adjust the positions of the original stage adjuster 10 and the substrate stage adjuster 24 during periodic maintenance or when the apparatus is restored in the event of an earthquake.
At this time, it is necessary to stop the operation of the apparatus, and the manual method has such annoyance.
However, if there is no need for adjustment over a long period of time, one or both of the original stage adjuster 10 and the substrate stage adjuster 24 may be manually operated in consideration of cost.

On the other hand, when the amount of change over time of the floor 8 is large and it is necessary to frequently drive the original stage adjuster 10 and the substrate stage adjuster 24, automatic adjustment is preferable because it affects the apparatus operating rate.
In this case, actuators are mounted on the original stage adjuster 10 and the substrate stage adjuster 24, and these actuators are driven by a control unit (not shown) based on the measured values of the surface plate sensors 12 and 23.
As a driving method, a method in which the actuators are constantly controlled so that the values of the sensors 12 and 23 between the platen plates are always set to values, and the measured value of the sensor deviates by a predetermined value or more. There is a method of performing control for the first time and returning to the installation state.
The driving method of the original stage adjuster 10 which is the first position adjusting mechanism and the substrate stage adjuster 24 which is the second position adjusting mechanism is a method suitable for a predetermined driving accuracy and cost, and includes a pneumatic driving mechanism, a hydraulic driving mechanism, It consists of either a piezo element drive mechanism or a motor drive mechanism.
Specific examples of driving systems include a pneumatic system that changes the position of the six axes by changing the pressure of the gas in the bellophram, and a hydraulic system that changes the position by flowing hydraulic oil into and out of the piston. Applied.
In addition, a gear system that changes the amount of rotation of the motor or the manual rotation shaft into horizontal, vertical, and tilt by combining gears, a method of changing the position using a piezo element, and the like are applied.
In the case of the above-described belofram system, vibration isolation is achieved by the effect of vibration isolation by the air spring, and the vibration isolation to the original stage adjuster 10 as the first position adjustment mechanism and the substrate stage adjuster 24 as the second position adjustment mechanism. Functions are also added.

In the first embodiment of the present invention shown in FIG. 1, only two functions of the original stage 2 and the illumination optical system 9 are mounted on the original stage surface plate 7.
However, in the modified example shown in FIG. 4, a TTR (throughtherthetic) microscope 27 that measures the substrate 14 through the projection optical system 13 is mounted.
As a function of the TTR microscope 27, the marks on the original plate 1 and the substrate 14 are superposed and observed, and the amount of misalignment is measured, while the imaging stage of the projection optical system 13 is swung up and down the substrate stage 20 It has functions such as searching and measuring aberrations of the projection optical system 13.
When the TTR microscope 27 is used, an optical component is inserted into the illumination area of the illumination optical system 9 and thus an exposure operation cannot be performed. Therefore, the normal origin exposure and position measurement calibration are performed instead of during normal exposure. Used for.
In order to be able to mount the TTR microscope 27, the relative positional deviation between the projection optical system 13 and the TTR microscope 27 must always be within the deviation amount allowed for TTR measurement.
For this reason, it is necessary to control the original stage adjuster 10 with finer precision.
In some cases, it is necessary to perform control such that the original stage surface plate follows the lens barrel surface plate 11.
As described above, in the first embodiment of the present invention shown in FIG. 1, even when the surface shape of the floor 8 changes, the change in the positional relationship of the original stage, the substrate stage, and the illumination optical system with respect to the projection optical system 13 is constant. It can be maintained below the amount, and the positional relationship can be maintained without shifting.
For this reason, the original stage, illumination optical system, and substrate stage are maintained at the correct positions with respect to the projection optical system, and the original original and substrate alignment accuracy is maintained, and finer circuit patterns are more uniform and without misalignment. Projection exposure is possible with a wide line width.
The conventional problem that it takes a long time to align the original 1 with the projection optical system 13 can be solved by securing a sufficient driving stroke of the driving mechanism of the first embodiment and appropriately managing the parts.
In other words, by managing the component accuracy of the mechanical parts, the positional relationship between the projection optical system 13 and the original stage 2 can be kept within a certain amount of deviation or less in a simple assembled state.

Next, a second embodiment of the present invention will be described.
In the first embodiment of FIG. 1, for example, the position measured by the inter-plate sensor 12 on the original plate 1 side and the upper part of the projection optical system 13 or the original plate stage 2 is changed with time. In the case of deformation, the position shift due to the deformation cannot be detected.
For this reason, the original stage adjuster 10 cannot remove the displacement due to the deformation.
In this case, since it is necessary to match the upper part of the projection optical system 13 and the original 1, it is important to arrange the inter-plate sensor 12 near the object to be matched.
If this arrangement is possible, it is desirable that the inter-plate sensor 12 measures the position close to the original plate 1 and the upper part of the projection optical system 13.
The configuration having the functions of the inter-plate position measuring function for the original stage adjuster 10, the laser interferometer 4 for controlling the position of the original stage 2 and the interferometer 15 for measuring the position of the projection optical system 13 is as follows. There is a case of arrangement.
That is, a sensor for controlling the original stage 2 is arranged directly from the upper part of the projection optical system 13.
This configuration is advantageous from the viewpoint of measurement error reduction and cost, but it is difficult to use such a configuration for all six axes.

Since the original stage 2 has an extremely small driving stroke in the X direction as compared with the substrate stage 20, the arrangement of the sensor is easier than the substrate stage 20.
Since the driving stroke in the height direction in addition to the X direction is extremely small, the control sensor for the five axes X, Z, ωx, ωy, and ωz among the six axes in the original stage 2 is relatively easy to project. 13 can be arranged.
Since the original stage 2 is driven in the range of several hundred millimeters in the Y direction, a sensor installation structure having a span of several hundred millimeters must be provided above the projection optical system 13 in order to cope with this driving amount.
It must be installed while maintaining sufficient rigidity, leading to an increase in weight.
In addition, when a sensor for measuring the position of a stage that drives such a span is used, there is no suitable sensor other than a laser interferometer.
Therefore, it becomes necessary to mount a laser head for the laser interferometer in the projection optical system. Since the laser head serves as a heat source, it is not preferable to mount the laser head on the projection optical system.
In consideration of the above, when a sensor is provided on the projection optical system 13 to control the position of the original stage 2, it is difficult to adopt such a configuration only for the Y axis.

In the second embodiment of the present invention shown in FIG. 5, a sensor is disposed in the projection optical system 13 to control the position of the 5-axis original stage 2 excluding the Y-axis.
FIG. 5 is a left side view of the exposure apparatus according to the first embodiment shown in FIG. 1, in which only portions different from the first embodiment shown in FIG. 1 are written. The portions not shown are the same as those shown in FIG. The components having the same functions as those in FIG. 1 are denoted by the same reference numerals as those in FIG.
The sensor 28 is a sensor that measures the X-direction reference plane of the original stage 2 from the projection optical system 13.
The sensor 28 is preferably a small laser interferometer having an origin detection function.
The sensor 28 composed of a small laser interferometer guides laser light from a light source through a fiber and measures the position of an object on the same principle as a normal laser interferometer, but has a large measurement range like a normal laser interferometer. I can't have.
However, if it is used for measuring a portion where the driving amount is extremely small, such as the X direction or the Z direction of the original stage 2, it can be measured without any problem.
Ωz can be measured by arranging another sensor composed of a small laser interferometer at a position shifted in the Y direction. This sensor is a small laser interferometer 29 for ωz measurement.
Displacement in the Z direction of the original stage 2 and ωx, ωy can be measured by arranging three similar small laser interferometers for Z direction measurement. This sensor is a small laser interferometer 30 for Z measurement. Yes, provided on the projection optical system 13.
Furthermore, a small laser interferometer 31 for ωx measurement is disposed at a position shifted on the Y axis, and a small laser interferometer 32 for ωy measurement is provided at a position shifted on the X axis.
With these arrangements, the position measurement used for the position control of the five axes excluding the Y axis of the original stage 2 can be performed directly from the projection optical system 13.
In this sensor arrangement, as shown in FIG. 1, the position of the projection optical system 13 is measured from the measuring board 3 by the laser interferometer 15, and the original stage 2 is measured by the laser interferometer 4 based on the measured value. This eliminates the need for complicated measurement systems and arithmetic processing such as control.
This is advantageous both in terms of accuracy and cost.

Next, a control method of the original stage adjuster 10 in the second embodiment shown in FIG. 5 will be described.
It is difficult to increase the measurement range of the small laser interferometers 28 to 31.
Therefore, when the position of the original stage 2 is indefinite, such as after assembly of the apparatus or immediately after the apparatus is turned on, the original stage with respect to the lens barrel surface plate 11 is first based on the measurement value of the surface plate sensor 12. The two positions are adjusted by the original stage adjuster 10.
The operation up to this point is the same as that of the first embodiment, and in this state, the measurement is possible because it enters the measurement range of the small laser interferometers 28 to 31.
With respect to the Y direction, the position adjustment is completed in this state, but the other five axes are finely adjusted using the small laser interferometers 28-31.
In performing fine adjustment, if the position of the original stage 2 is indefinite with respect to the original stage surface plate 7, the position adjustment of the original stage surface plate 7 cannot be performed based on the measurement value of the small laser interferometer.
This is because the small laser interferometers 28 to 31 measure the position of the original stage 2, and therefore the measured values have no meaning when the position of the original stage 2 to be measured is indefinite.
Therefore, it is necessary to first position the original stage 2 at a predetermined position with respect to the original stage surface plate 7.
This position is preferably the center of the 6-axis drive stroke of the original stage 2 as much as possible.
Alternatively, the position may be deviated from the center of the stroke as long as it is within the measurement range of the small laser interferometers 28 to 31, but in this case, the amount of deviation is known in advance, and the position of the substrate stage surface plate 7 is taken into consideration. Is preferably adjusted by the substrate stage adjuster 10.

As a measuring means for positioning the original stage 2 with respect to the original stage surface plate 7, sensors for measuring the absolute position such as eddy current sensors 28 to 31 and a laser interferometer with an origin detecting function such as a capacitance sensor are used. May be.
Further, a sensor that reacts when an object comes to a certain position, such as a photo sensor or other proximity sensor, may be used, and in some cases, the position may be determined by mechanical abutment.
In the second embodiment of FIG. 5, positioning is performed by mechanical abutment in the Z direction and a proximity switch 33 in the X direction.
The values of the small laser interferometers 28 to 31 are measured in a state where the original stage 2 is positioned with respect to the original stage surface plate 7 by the above means.
The original stage adjuster 10 is driven so that the values of the small laser interferometers 28 to 31 become predetermined values.
As in the first embodiment, when the rate of change of the floor 8 with time is sufficiently slow, the original stage adjuster 10 may be manually operated.
However, depending on the frequency of adjustment and the time required for adjustment, it is preferable to drive the measurement values of the small laser interferometers 28 to 31 to a predetermined value by an automatic drive mechanism using an actuator.
The value of the small laser interferometer as the target value at this time is obtained in advance when assembling and adjusting the projection optical system.
Since the small laser interferometers 28 to 31 have a built-in origin detection function, they can be used as an absolute distance measuring device.
Further, as described above, when the position of the original stage 2 is not the center of the driving stroke and the deviation amount is known at this time, the adjustment amount of the original stage adjuster 10 is shifted by the deviation amount.
As described above, the position of the original stage 2, that is, the original 1 can be accurately aligned with the projection optical system 13.
Unlike the original stage 2, the substrate stage 20 has a large driving stroke in the X direction.
For this reason, it is difficult to arrange on the substrate stage 20 a small laser interferometer measuring mirror that directly measures the stage position from the projection optical system 13 as in the second embodiment over the entire stroke.
However, since it can be arranged within a limited range, positioning means similar to the original stage 2 of the second embodiment can be performed by the substrate stage adjuster 24.

In both the first and second embodiments, the original stage adjuster 10 and the substrate stage adjuster 24 are not only used for alignment during assembly and for correcting a shift due to a temporal change in the surface of the floor 8, but also when performing exposure. It can also be used when it is necessary to intentionally change.
For example, as a means for apparently increasing the depth of focus of the projection optical system 13, there are cases where scan exposure is performed with the original stage 2 and the substrate stage 20 tilted to ωx.
In this case, it is not preferable from the viewpoint of the size, power consumption, and cost of the mechanism to have all the stage drive strokes required in this case in the original stage 2 and the substrate stage 20.
At this time, the original stage 2 and the substrate stage 20 can be manufactured compactly with low power consumption and low cost by inclining the amount of inclination using the original stage adjuster 10 and the substrate stage adjuster 24.
In addition, although the original stage adjuster 10 is arranged at the same position in both the first and second embodiments, the original stage adjuster 10 is not limited to this position, and is placed on the surface of the floor 8 like the substrate stage adjuster 24, for example. You can also.
Further, a dedicated adjustment mechanism may be provided in the illumination optical system 9 depending on the arrangement in the apparatus.
In this case, an inter-plate sensor for measuring the position of the lens barrel base plate 11 from the illumination optical system 9 is required.
Similarly, in the case of a modified exposure apparatus equipped with the TTR microscope 27, an independent adjustment mechanism may be provided under the TTR microscope 27.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described with reference to FIGS.
FIG. 6 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, and the like). Here, a semiconductor chip manufacturing method will be described as an example.
The method comprises the steps of exposing a wafer using an exposure apparatus and developing the wafer, and specifically comprises the following steps.
In step 1 (circuit design), a semiconductor device circuit is designed.
In step 2 (mask production), a mask is produced based on the designed circuit pattern.
In step 3 (wafer manufacture), 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 using the mask and the wafer by the above exposure apparatus using the lithography technique.
Step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and an assembly process such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), or the like. including.
In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test.
Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 7 is a detailed flowchart of the wafer process in Step 4.
In step 11 (oxidation), the surface of the wafer is oxidized.
In step 12 (CVD), an insulating film is formed on the surface of the wafer.
In step 13 (electrode formation), an electrode is formed on the wafer.
In step 14 (ion implantation), ions are implanted into the wafer.
In step 15 (resist process), a photosensitive agent is applied to the wafer.
Step 16 (exposure) uses the exposure apparatus to expose a circuit pattern on the mask onto the wafer.
In step 17 (development), the exposed wafer is developed.
In step 18 (etching), portions other than the developed resist image are removed.
In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed.
By repeatedly performing these steps, multiple circuit patterns are formed on the wafer.

1 is an overall schematic diagram of an exposure apparatus according to a first embodiment of the present invention. It is a block diagram which shows the state which the floor deform | transformed in the reference example of this invention which does not have the 1st and 2nd position adjustment mechanism. In Example 1 of this invention of FIG. 1, it is a block diagram which shows the state which the floor deform | transformed. It is a block diagram of the modification by which the TTR microscope of Example 1 of this invention was mounted. It is a block diagram of Example 2 of this invention which controls the position of an original stage with the sensor arrange | positioned on a projection optical system. It is a flowchart for demonstrating manufacture of the device using an exposure apparatus. It is a detailed flowchart of the wafer process of step 4 of the flowchart shown in FIG.

Explanation of symbols

BM1 Original stage bar mirror BM2 Substrate stage bar mirror 1 Original 2 Original stage 3 Total measuring panel 4 Laser interferometer 5, 6 Base frame 7 Original stage surface plate 8 Floor 9 Illumination optical system 10 Original stage adjuster 11 Lens barrel surface plate 12 Inter-board sensor 13 Projection optical system 14 Substrate 15 Laser interferometer 16 Lens barrel mount 17 Lens barrel surface plate mount 18 Mark position measuring microscope 19 Laser interferometer 20 Substrate stage 21 Laser interferometer 22 Substrate stage surface plate 23 Inter-plate sensor 24 Substrate stage adjuster 25 Substrate stage surface plate 26a, 26b Interferometer beam 27 TTR microscope 28 X measurement small laser interferometer 29 ωz measurement small laser interferometer 30 X direction measurement substrate stage side laser interferometer 31 Z measurement small size Laser interferometer 32 ωy measurement Small laser interferometer 33 proximity sensor

Claims (6)

An exposure apparatus that illuminates an original through an illumination optical system with exposure light from a light source and projects and exposes a pattern formed on the original onto a substrate through a projection optical system,
An original stage on which the original is mounted;
A first structure that supports the illumination optical system and the original stage;
An exposure apparatus comprising: a first position adjusting mechanism that adjusts a position of the original stage between the first structure and a floor. A base frame that supports the first structure via the first position adjustment mechanism;
2. The exposure apparatus according to claim 1, wherein the base frame is installed on a floor. A substrate stage on which the substrate is mounted;
A second structure for supporting the substrate stage;
A second position adjusting mechanism for adjusting the position of the substrate stage between the second structure and the floor;
3. An exposure apparatus according to claim 1, wherein a change in a positional relationship between the projection optical system and the substrate stage is kept below a certain amount.   2. The measuring means for measuring a positional relationship between the projection optical system and the original stage or the substrate stage is an eddy current sensor or a capacitance sensor, and is a sensor for measuring an absolute position. 4. The exposure apparatus according to any one of items 1 to 3.   5. The first position adjusting mechanism or the second position adjusting mechanism comprises any one of a pneumatic driving mechanism, a hydraulic driving mechanism, a piezo element driving mechanism, and a motor driving mechanism. The exposure apparatus according to any one of the above. A step of exposing a substrate using the exposure apparatus according to claim 1;
And a step of developing the substrate.

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