JP2000331904A - Exposure device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further accurately correct the measured value of the position measuring means of a stage. SOLUTION: This exposure device is provided with movable stages 2 and 4, plural position measuring equipment 5, 7; 6, 8 for measuring the positions of the stages, plural fluctuating factor measuring equipment for measuring fluctuating factors affecting the measured results of the plural position measuring equipment, and a measurement correcting means 11 for correcting the measured results of the position measuring equipment based on the measured result of the fluctuating factor measuring equipment. The plural fluctuating factor measuring equipment individually measure the fluctuating factors for each of the plural position measuring equipment, and the measurement correcting means individually corrects each measured result of the position measuring equipment based on the individual measured result of the plural fluctuating factor measuring equipment.

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 a device manufacturing method using the same.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a method for correcting a wavelength of a laser interferometer in a conventional scan exposure apparatus. As shown in FIG. 1, the exposure apparatus includes a reticle 10
Reticle stage 102 on which wafer 1 is mounted, wafer stage 104 on which wafer 103 is mounted, and reticle stage 10
2. Reticle X-axis laser interferometer 105 for X-direction length measurement
A reticle Y-axis laser interferometer 106 for measuring the Y direction of the reticle stage 102;
Wafer X-axis laser interferometer 107 for direction measurement, wafer Y-axis laser interferometer 108 for Y-direction length measurement of wafer stage 104, reticle X-axis laser interferometer 105 and reticle Y near reticle stage 102 A reticle stage interferometer wavelength corrector 109 for correcting the measurement value of the axis laser interferometer 106 and a wafer X-axis laser interferometer 107 and a wafer Y-axis laser interferometer 108 near the wafer stage 104 for correcting the measurement value. A wafer stage interferometer wavelength corrector 110, a stage position measuring device 111,
A stage controller 112, a current amplifier 113 for supplying a desired current to a linear motor of each stage,
114.

[0003] The stage position measuring device 111 is a reticle X
Axis laser interferometer 105, reticle Y axis laser interferometer 10
6. Position information of the reticle stage 102 and the wafer stage 104 is input using the wafer X-axis laser interferometer 107 and the wafer Y-axis laser interferometer 108. The stage position measuring device 111 is a wavelength corrector for a reticle stage interferometer (a wavelength tracker for a reticle stage).
Using 109 and a wafer stage interferometer wavelength corrector (wafer stage wavelength tracker) 110, wavelength correction information for reticle stage position information and wavelength correction information for wafer stage position information are also input. Further, the stage position measuring device 111 calculates the corrected position information using each stage position information and each stage wavelength correction information, and outputs the corrected position information of each stage to the stage controller 112.

A stage controller 112 calculates a current command value of each actuator of each stage based on the correction position information of each stage inputted from the stage position measuring device 111 and each stage drive command information inputted from the host CPU 114. Then, the current command information is output to the current amplifier 113 for driving each actuator of each stage. Current amplifier 1
Reference numeral 13 inputs the current command information from the stage controller 112, supplies a current to the linear motor of each stage, and drives each stage. In such a configuration, the laser interferometer utilizes the wavelength of the laser light as the basic scale length. However, in air, the wavelength of the laser light is affected by the refractive index of air, which is a function of air temperature, pressure and relative humidity. In the case of a He-Ne laser, if any one of a change in air temperature by 1 ° C., a change in air pressure by 2.5 mmHg, and a change in relative humidity by 80% occurs, the wavelength of the laser light changes by 1 ppm and 1 ppm. Measurement error occurs. Therefore, correcting a change in the wavelength of the laser light due to a change in the environment improves the accuracy and reproducibility of the laser interferometer, and leads to an improvement in the stage drive control performance.

In general, correction methods include measuring the temperature, pressure, and humidity of air in a portion through which a laser passes, and calculating the refractive index of the air, and adding a laser reference axis to calculate the refractive index of the air. There is a method in which the change is directly measured and corrected, and any of the methods can correct a change in the measured value of the interferometer due to a change in the environment.

[0006] In recent years, the stage performance required in a semiconductor exposure apparatus has become even more precise, and accordingly, there has been a demand for higher precision in stage position measurement. It has become necessary to more strictly correct the measurement value of the laser interferometer with respect to environmental changes around the stage. Strictly speaking,
The temperature is different between the upper part of the stage linear motor and the part that is not. In addition, in the vicinity of the stage, the air pressure is different near the temperature control air outlet from the temperature control duct and in a portion other than the temperature control air outlet.

[0007]

However, in the above conventional example, the wavelength corrector for the reticle stage interferometer (wavelength tracker for the reticle stage) 109 and the wavelength corrector for the wafer stage interferometer (wavelength tracker for the wafer stage)
Due to the large outer dimensions of 110, the location of these wavelength correctors is limited, and at present one is provided around the reticle stage and one around the wafer stage. Therefore, strictly speaking, since the environment in each laser beam passing portion of each laser interferometer is not individually detected and corrected and measured, there is a problem that wavelength correction is not strictly performed at present. .

SUMMARY OF THE INVENTION In view of the problems of the prior art, it is an object of the present invention to make it possible to more strictly correct the wavelength of each measurement value of each laser interferometer.
An object of the present invention is to provide an exposure apparatus with higher performance and a device manufacturing method capable of manufacturing a device with higher accuracy. Another object of the present invention is to minimize environmental changes around the stage and temperature gradients around the linear motor of the stage so that wavelength correction can be performed more strictly.

[0009]

In order to achieve the above object, an exposure apparatus according to the present invention comprises a movable stage, a plurality of position measuring devices for measuring the position of the stage, and measurement of the plurality of position measuring devices. A plurality of variation factor measuring devices for measuring variation factors affecting results, and measurement correction means for correcting a measurement result of the position measurement device based on a measurement result of the variation factor measuring device, wherein the plurality of variation The factor measuring device is for separately measuring the variation factor for each of the position measuring devices of the plurality of position measuring devices, and the measurement correcting means is based on the separate measurement results of the plurality of variation factor measuring devices, It is characterized in that each measurement result of the position measuring device is separately corrected.

Further, the device manufacturing method of the present invention includes a step of preparing such an exposure apparatus and a step of exposing a pattern formed on an original plate to a substrate using the exposure apparatus. I do.

In the configuration of the present invention, since the variation factor measuring device separately measures the variation factor for a plurality of position measuring devices, the measurement result of the common variation factor is applied to each position measuring device. Compared to the prior art, a more suitable measurement of the variation factor is performed for each position measuring instrument. Therefore, the measurement result of each position measuring device corrected by the measurement results of these more suitable fluctuation factors becomes a more accurate measurement result with more strict correction.

[0012]

In a preferred embodiment of the present invention, the position measuring device has a laser interferometer for measuring the position or the angle, and the fluctuation factor measuring device has first and second fluctuation factors as the fluctuation factors. First and second detecting means for detecting the atmospheric pressure and temperature in the vicinity of each of the position measuring devices, or first for measuring the temperature, pressure and humidity in the vicinity of each of the first and second position measuring devices as a variable factor.
And a second air sensor. In this case, the environment of the laser light passing portion of each laser interferometer that measures in the first and second directions is detected by the atmospheric pressure or temperature detecting means or the air sensor, respectively, and the measured value correcting means detects the environment of each laser interferometer. Strict wavelength correction of the measured value is performed. In addition, there is provided cooling means for cooling the stage actuator while adjusting the cooling amount based on the measurement result of the fluctuation factor measuring device. The cooling means performs cooling while adjusting the flow rate and / or temperature of the cooling water. At this time, the cooling means individually adjusts the cooling amounts of the plurality of actuators for driving the stage based on the measurement results of the fluctuation factors separately measured by the fluctuation factor measuring device for the first and second position measuring means. While cooling. This suppresses environmental changes around the stage and temperature gradients around the linear motor. Therefore, the wavelength correction for the measurement value of each laser interferometer is performed more accurately.

[0013]

FIG. 1 is a block diagram showing a configuration relating to wavelength correction of a laser interferometer in a scan exposure apparatus according to a first embodiment of the present invention. Well represented. As shown in FIG. 1, the exposure apparatus includes a reticle stage 2 on which a reticle 1 is mounted, a wafer stage 4 on which a wafer 3 is mounted, and a reticle stage 2.
A reticle X-axis laser interferometer 5 for measuring the X-direction, a reticle Y-axis laser interferometer 6 for measuring the Y-direction of the reticle stage 2, and a wafer X for measuring the X-direction of the wafer stage 4.
Axis laser interferometer 7, wafer Y axis laser interferometer 8 for measuring the length of wafer stage 4 in the Y direction, and stage position measuring instrument 1
1, a stage controller 12, a current amplifier 13 for supplying a desired current to the linear motor of each stage,
U14. Reference numeral 15 denotes a reticle X-axis temperature detector arranged near the laser beam optical path of the reticle X-axis laser interferometer 5, 16 denotes a reticle X-axis pressure detector arranged near the laser beam optical path of the reticle X-axis laser interferometer 5.
Reference numeral 7 denotes a reticle Y-axis temperature detector disposed near the laser beam optical path of the reticle Y-axis laser interferometer 6, reference numeral 18 denotes a reticle Y-axis pressure detector disposed near the laser beam optical path of the reticle Y-axis laser interferometer 6, and reference numeral 19 denotes A wafer X-axis temperature detector arranged near the laser beam optical path of the wafer X-axis laser interferometer 7, a wafer X-axis pressure detector 20 arranged near the laser beam optical path of the wafer X-axis laser interferometer 7, and a wafer Y A wafer Y-axis temperature detector 22 is disposed near the laser beam path of the axis laser interferometer 8, and a wafer Y-axis pressure detector 22 is disposed near the laser beam path of the wafer Y-axis laser interferometer 8. In the above configuration, the stage position measuring device 11 calculates the reticle X-axis correction measurement value from the measurement values of the reticle X-axis laser interferometer 5, the reticle X-axis temperature detector 15, and the reticle X-axis atmospheric pressure detector 16, and The reticle Y-axis correction measurement value is calculated from the measurement values of the Y-axis laser interferometer 6, the reticle Y-axis temperature detector 17, and the reticle Y-axis pressure detector 18, and the wafer X-axis laser interferometer 7 and the wafer X-axis temperature detector A wafer X-axis correction measurement value is calculated from the measurement values of 19 and the wafer X-axis pressure detector 20, and the measurement values of the wafer Y-axis laser interferometer 8, the wafer Y-axis temperature detector 21, and the wafer Y-axis pressure detector 22 are calculated. Calculate the wafer Y-axis correction measurement value.
That is, the reticle X-axis correction measurement value is a measurement value obtained by performing wavelength correction based on the temperature and the pressure around the optical path of the reticle X-axis laser interferometer 5, and the reticle Y-axis correction measurement value is the reticle Y-axis laser interferometer 6. Is a measurement value obtained by performing wavelength correction based on the temperature and the atmospheric pressure around the optical path of the wafer, and the wafer X-axis corrected measured value is a measurement obtained by performing the wavelength correction based on the temperature and the atmospheric pressure around the optical path of the wafer X-axis laser interferometer 7. The wafer Y-axis correction measurement value is a measurement value obtained by performing wavelength correction based on the temperature and the air pressure around the optical path of the wafer Y-axis laser interferometer 8. The stage controller 12 is a stage position measuring device 1
Each correction measurement value of each stage input from 1 and the upper CP
Based on each stage drive command value input from U14, a control constant, and the like, a current command value of each actuator of each stage is calculated, and current command information is output to the drive current amplifier 13 of each actuator of each stage. The current amplifier 13 receives current command information from the stage controller 12, supplies current to the linear motor of each stage, and drives each stage. This makes it possible to more strictly correct the wavelength of the laser interferometer with respect to an environmental change in a portion where each laser beam passes. In particular, although the air pressure is strictly different between the temperature control air blow-out from the temperature control duct and the portion other than the temperature control air outlet, the wavelength correction can be performed more strictly. As a result, the measured value of each laser interferometer can be corrected more strictly in wavelength, which leads to an improvement in device performance.

In this embodiment, the temperature and the pressure around the optical path of the interferometer for measuring the position of each stage in the X-axis direction and the Y-axis direction are measured. However, the present invention is not limited to this. Direction, Z-axis direction and Tilt direction
The temperature and pressure around the optical path of the interferometer that performs the rotation measurement may be measured, and the measured values of each interferometer may be corrected.

(Second Embodiment) FIG. 2 is a block diagram showing a configuration related to wavelength correction of a laser interferometer in a scan exposure apparatus according to a second embodiment of the present invention. In this exposure apparatus, the temperature detectors 15 and 17 in the first embodiment,
The air pressure sensors 19, 21 and the air pressure detectors 16, 18, 20, 22 are replaced with air sensors for measuring temperature, air pressure and humidity. In the figure, reference numerals 1 to 14 are the same as the elements denoted by the same reference numerals in the above-described embodiment. Reference numeral 23 denotes a reticle X-axis air sensor disposed near the laser beam optical path of the reticle X-axis laser interferometer 5, reference numeral 24 denotes a reticle Y-axis air sensor disposed near the laser beam optical path of the reticle Y-axis laser interferometer 6, and reference numeral 25 denotes a wafer X-axis laser. Interferometer 7
Reference numeral 26 denotes a wafer Y-axis air sensor disposed near the laser beam path of the wafer Y-axis laser interferometer 8. In the above configuration, the stage position measuring device 11 calculates the reticle X-axis correction measurement value from the measurement values of the reticle X-axis laser interferometer 5 and the reticle X-axis air sensor 23, and uses the reticle Y-axis laser interferometer 6 and the reticle Y-axis. The reticle Y-axis correction measurement value is calculated from the measurement value of the air sensor 24, the wafer X-axis correction measurement value is calculated from the measurement value of the wafer X-axis laser interferometer 7 and the wafer X-axis air sensor 25, and the wafer Y-axis laser interferometer 8 is calculated.
Then, a wafer Y-axis correction measurement value is calculated from the measurement value of the wafer Y-axis air sensor 26. That is, the reticle X-axis correction measurement value is a measurement value obtained by performing wavelength correction based on the temperature, the atmospheric pressure, and the humidity around the optical path of the reticle X-axis laser interferometer 5, and the reticle Y-axis correction measurement value is the reticle Y-axis laser interference. This is a measurement value obtained by performing wavelength correction based on the temperature, pressure, and humidity around the optical path of the total 6, and the measured value of the wafer X-axis correction is based on the temperature, pressure, and humidity around the optical path of the wafer X-axis laser interferometer 7. The measured value is a wavelength-corrected measurement value, and the wafer Y-axis corrected measurement value is a measured value obtained by performing a wavelength correction based on the temperature, the atmospheric pressure, and the humidity around the optical path of the wafer Y-axis laser interferometer 8. The stage controller 12 controls each actuator of each stage based on the above-described corrected measurement values of each stage input from the stage position measuring device 11, each stage drive command value input from the host CPU 14, a control constant, and the like. A current command value is calculated, and current command information is output to the drive current amplifier 13 of each actuator of each stage. The current amplifier 13 receives current command information from the stage controller 12, supplies a current to the linear motor of each stage, and drives each stage. The effect of this is the first
This is the same as the embodiment.

In this embodiment, the temperature and the pressure around the optical path of the interferometer for measuring the position of each stage in the X-axis direction and the Y-axis direction are measured, but the present invention is not limited to this. Direction, Z-axis direction and Tilt direction
The temperature and pressure around the optical path of the interferometer that performs the rotation measurement may be measured, and the measured values of each interferometer may be corrected.

(Third Embodiment) FIG. 3 is a block diagram around a wafer stage according to a third embodiment of the present invention. In the figure, 3, 4, 7, 8, 11 to 14, 19 to 22
Are the same as the elements denoted by the same reference numerals in the first embodiment of FIG. 27 is a wafer X-axis temperature detector 19
X-axis laser interferometer 7 from wafer and wafer Y-axis temperature detector 21
Temperature information around the beam and the temperature information around the beam of the Y-axis laser interferometer 8 are
A stage actuator individual cooling water adjusting means for calculating a cooling water flow rate or a cooling water temperature to be supplied to each of the linear motors on the right axis and the left Y axis respectively. Cooling water temperature) information 32 is input, and stage Y axis right linear motor cooling water 29, stage Y axis left linear motor cooling water 30, and stage X axis linear motor cooling water 31 are input.
These are stage actuator individual cooling means for changing the respective cooling water flow rates (cooling water temperatures). In the above configuration, when the detector 19 or 21 detects a temperature rise, the flow rate of the cooling water flowing through the linear motor close to the detector that detected the temperature rise is increased, or the temperature of the cooling water is lowered, and the stage near the detector is increased. The stage actuator individual cooling water adjusting means 27 works so as to suppress the temperature rise in the surrounding area. As a result, not only can the measured value of each laser interferometer be accurately corrected for the change in the environment around the stage, but also the environment change around the stage and the temperature gradient around the linear motor of the stage can be suppressed as much as possible. As a result, the performance of the device is further improved.

An air sensor may be used in place of the temperature detectors 19 and 21 to obtain information on the beam peripheral temperature of the X-axis laser interferometer 7 and the beam peripheral temperature of the Y-axis laser interferometer 8.

<Embodiment of Device Manufacturing Method> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 5 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin film magnetic heads, micro machines, etc.). In step 1 (circuit design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass.
Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing, bonding),
It includes steps such as a packaging step (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 6 shows the wafer process (step 4).
The detailed flow of is shown. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a resist is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus or exposure method to align and print the circuit pattern of the mask on a plurality of shot areas of the wafer.
Step 17 (development) develops the exposed wafer.
In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps,
Multiple circuit patterns are formed on the wafer.

By using the production method of this embodiment, a large-sized device, which has been conventionally difficult to produce, can be produced at low cost.

[0022]

As described above, according to the present invention, the fluctuation factors are separately measured for a plurality of position measuring instruments, and the measurement results of the plurality of position measuring instruments are individually measured based on these separate measurement results. Since the correction is performed, the measurement value of each position measuring device can be corrected more strictly based on the measurement result of the more suitable variation factor for each position measuring device. When the position measuring device is a laser interferometer and the fluctuation factor measuring device is a pressure and temperature detecting means or an air sensor, the pressure of the laser light passing portion of each laser interferometer detected by these detecting means, The wavelength correction of the measurement value of each laser interferometer can be strictly performed based on the temperature and the like. Therefore, it is possible to improve the performance of the apparatus and the accuracy of device manufacturing.

Further, the actuator of the stage is cooled while adjusting the cooling amount based on the measurement result of the fluctuation factor measuring device. Further, for the plurality of actuators for driving the stage, the fluctuation factor measuring device is used for the plurality of position measuring devices. Based on the measurement results of the separately measured fluctuation factors, cooling is adjusted while adjusting the cooling amount separately, so that environmental changes around the stage and temperature gradients around the linear motor are suppressed, and the measured value of each laser interferometer is reduced. The wavelength correction can be performed more accurately. Therefore, the performance of the apparatus and the accuracy of device manufacture can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration related to wavelength correction of a laser interferometer in a scan exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration related to wavelength correction of a laser interferometer in a scan exposure apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration around a wafer stage according to a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating a wavelength correction method of a laser interferometer in a conventional scan exposure apparatus.

FIG. 5 is a flowchart showing a device manufacturing method that can use the exposure apparatus of the present invention.

FIG. 6 is a detailed flowchart of a wafer process in FIG. 5;

[Explanation of symbols]

1: reticle, 2: reticle stage, 3: wafer,
4: wafer stage, 5: reticle X-axis laser interferometer,
6: reticle Y-axis laser interferometer, 7: wafer X-axis laser interferometer, 8: wafer Y-axis laser interferometer, 9: wavelength corrector for reticle stage interferometer, 10: wavelength corrector for wafer stage interferometer, 11 : Stage position measuring instrument, 12: stage controller, 13: current amplifier, 14: host CPU,
15: reticle X axis temperature detector, 16: reticle X axis pressure detector, 17: reticle Y axis temperature detector, 18: reticle Y axis pressure detector, 19: wafer X axis temperature detector, 2
0: Wafer X-axis pressure detector, 21: Wafer Y-axis temperature detector, 22: Wafer Y-axis pressure detector, 23: Reticle X-axis air sensor, 24: Reticle Y-axis air sensor, 25: Wafer X-axis air sensor, 26: Wafer Y-axis air sensor, 2
7: Stage actuator individual cooling water adjusting means, 2
8: Stage actuator individual cooling means, 29: Stage Y-axis right linear motor cooling water, 30: Stage Y-axis left linear motor cooling water, 31: Stage X-axis linear motor cooling water, 32: Stage cooling water flow rate (cooling water temperature) ).

Claims (11)

[Claims] 1. A movable stage, a plurality of position measuring devices for measuring the position of the stage, and a plurality of variation factor measuring devices for measuring a variation factor affecting a measurement result of the plurality of position measuring devices. Measuring correction means for correcting the measurement result of the position measuring device based on the measurement result of the fluctuation factor measuring device, wherein the plurality of fluctuation factor measuring devices determine the position of the plurality of position measuring devices by using the fluctuation factors. The measurement device is separately measured, and the measurement correction means separately corrects each measurement result of the position measurement device based on separate measurement results of the plurality of variation factor measurement devices. Exposure apparatus characterized by the above-mentioned. 2. The exposure apparatus according to claim 1, wherein the position measuring device has a laser interferometer. 3. The exposure apparatus according to claim 1, wherein the fluctuation factor measuring device detects an atmospheric pressure and a temperature near the position measuring device or near a measurement optical path. 4. The exposure apparatus according to claim 1, wherein the fluctuation factor measuring device detects a temperature, an atmospheric pressure, and a humidity near the position measuring device or near a measurement optical path. 5. The exposure apparatus according to claim 1, wherein a cooling amount of a cooling mechanism that cools an actuator that drives the stage is controlled based on a measurement result of the variation factor measuring unit. . 6. A plurality of actuators for driving a stage, and a plurality of cooling mechanisms for individually cooling the plurality of actuators, wherein the cooling mechanism is based on separate measurement results of the plurality of fluctuation factor measuring devices. The exposure apparatus according to any one of claims 1 to 5, wherein a cooling amount of each actuator is adjusted. 7. The exposure apparatus according to claim 1, wherein the cooling mechanism has a mechanism for adjusting a flow rate or a temperature of the refrigerant. 8. The exposure apparatus according to claim 1, wherein the stage is mounted and moves. 9. A device comprising: a step of preparing the exposure apparatus according to claim 1; and a step of exposing a pattern formed on an original plate to a substrate using the exposure apparatus. Production method. 10. The stage according to claim 9, wherein when controlling the position of the stage, the actuator of the stage is cooled while adjusting the cooling amount based on the measurement result of the fluctuation factor measuring device. Device manufacturing method. 11. The device manufacturing method according to claim 9, further comprising a step of applying a developer to the substrate and a step of developing the exposed substrate.