JPH0672983B2 - Projection optics - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a projection optical apparatus capable of easily correcting optical characteristics such as a magnification characteristic, an image plane characteristic, and various aberration characteristics of a projection optical system.

(Background of the Invention) A reduction projection type exposure apparatus (hereinafter referred to as a stepper) has been recently used as an LS
It has been introduced to many production sites of I and has brought great results, but one of its important performances is overlay matching accuracy. An important factor that affects the matching accuracy is a magnification error of the projection optical system. Super
The size of patterns used in LSIs is becoming finer year by year, and along with this, there is a strong need for improvement in matching accuracy. Therefore, the necessity of keeping the projection magnification at a predetermined value has become extremely high. At present, the magnification of the projection optical system is adjusted to such an extent that the magnification error can be neglected by adjusting the magnification when the apparatus is installed.

However, the projection lens of the stepper absorbs a part of the exposure energy and the temperature rises. Therefore, the projection lens may be continuously irradiated with exposure light for a long time, or if the exposure operation is continuously performed for a long time, the magnification may change to a level that cannot be ignored. Further, there is an increasing demand for correcting magnification errors when environmental conditions change, such as a slight change in temperature around the projection lens and a slight change in atmospheric pressure in a clean room when the apparatus is in operation.

These magnification errors may pose a practical problem even if they are about 0.05 μm on the image plane, and it has been extremely difficult to correct such a minute magnification variation and always maintain a constant state. Moreover, in the projection lens, not only does the magnification change due to the temperature rise of the projection lens due to exposure energy and changes in environmental conditions, but also changes in the image plane and aberrations occur, and these optical performances also change. However, even if only certain specific optical performance such as magnification is corrected, deterioration in the overall optical performance may be unavoidable even if only certain specific optical performance such as magnification is corrected. Furthermore, since changes in various optical performances are generally closely related to each other rather than independent of each other, it is extremely difficult to actively fine-tune a specific optical performance, for example, only the magnification independently. It was

(Object of the Invention) It is an object of the present invention to provide a projection optical apparatus capable of easily performing fine adjustment of various optical performances such as a magnification of a projection lens and an image forming surface, and further, a magnification and an image forming surface. Another object of the present invention is to provide a projection optical apparatus capable of independently correcting various optical performances such as aberration.

(Summary of the Invention) The present invention shuts off at least two air chambers from the outside air among a plurality of air chambers formed by lens surfaces in a lens system constituting a projection lens, and connects these at least two air chambers. The optical performance of the projection lens is corrected or finely adjusted by controlling the pressure of the combined air chamber.

In this way, if at least two air chambers are communicated and their pressures are controlled at the same time, for example, a magnification change due to the pressure control of each air chamber will occur at the same time, and the change due to each air chamber will be added, so that unit control of pressure is performed. The magnification correction amount per amount can be increased, and fine adjustment of the magnification becomes easy. Moreover,
In addition to the change in magnification due to each air chamber, attention is paid to the change in the image plane, and as the at least two air chambers that are combined and pressure-controlled, for example, an air chamber in which the amount of change in the image plane cancels each other out. If these are selectively cut off from the outside air and the pressure is controlled, it is possible to correct or positively adjust only the magnification while keeping the image forming surface constant. On the contrary, if at least two air chambers in which the fluctuation amounts of the magnifications cancel each other are cut off from the outside air and are communicatively coupled to each other, and pressure control is performed, only the imaging plane is maintained while the magnification is kept substantially constant. It is possible to correct or positively adjust. Furthermore, if it is possible to cancel the fluctuations of both the magnification and the image plane by combining a plurality of air chambers, only specific aberrations such as spherical aberration, coma aberration, or image plane distortion distortion can be independent. Can be corrected to.

As described above, when at least two air chambers are connected in communication and their pressures are integrally controlled, the correction amount per unit pressure control amount of a certain optical performance is increased by the combination of the air chambers. In addition, it is possible to independently correct and finely adjust only a certain specific optical performance. In these cases, there is substantially one space for pressure control and only one pressure control device is required. However, as described above, the optical performances of the projection lens often change intricately due to various factors such as temperature rise due to the exposure energy of the projection lens and changes in environmental conditions, and it is not possible to correct only specific optical performances. Often sufficient. For this reason, if a plurality of combined air chambers communicating with at least two air chambers as described above are set and a plurality of pressure control devices are also provided, the degree of freedom in correction increases, and a plurality of simultaneous fluctuations in optical performance due to various factors. It becomes possible to satisfactorily correct even.

(Example) Now, in the existing lens space of the projection objective lens, two places are configured as air chambers which are shielded from the outside air, and when the pressure in the air chamber changes by a unit pressure from the time of setting the initial magnification, the magnification is changed. The amount of change, that is, the amount of displacement of a predetermined off-axis image point on the image plane is assumed to be ΔX ₁ and ΔX ₂ , respectively. It is assumed that a part of the air chambers other than this air chamber undergoes the same pressure change as the atmospheric pressure, and a magnification change of ΔXp occurs with respect to a unit pressure change ΔP of the atmospheric pressure. If the other air chamber among the air chambers formed in the projection lens is hermetically sealed and shielded from the atmosphere, there is no change in atmospheric pressure, so that there is no variation in magnification.

Therefore, if the two shut-off air chambers are connected to be connected to an integrated air chamber and the pressure in the combined air chamber is controlled, the magnification change amount Δ due to a change in unit pressure of atmospheric pressure Δ
To Xp, when the pressure control amount of the binding air chamber _{△ P I, (1) △} P I (△ X 1 + △ X 2) + △ P △ I to meeting Xp = 0 connexion atmospheric pressure It is possible to correct the magnification change due to the fluctuation ΔP. Here, by selecting the ones with the same sign of ΔX ₁ and ΔX ₂ , it is possible to obtain a larger change amount than the correction change amount by only one air chamber, so a smaller pressure control amount is required. It is possible to correct magnification variation due to atmospheric pressure. Therefore, since the pressure fluctuation width of the air chamber in which the pressure is controlled is relatively small, the risk of air leakage is small and the control is easy.

However, it is generally unavoidable that the imaging plane also fluctuates due to the pressure fluctuations of these two air chambers. Therefore,
It is assumed that the third air chamber is also communicated and connected to integrally control the pressure. That is, the image plane change amounts with respect to the unit pressure changes in the two air chambers are ΔZ ₁ and ΔZ ₂ respectively.
If the magnification change amount for the unit pressure change in the third air chamber is ΔX ₃ and the image plane change amount is ΔZ ₃ , then the relation ΔZ ₃ = ΔZ ₁ + ΔZ ₂ is satisfied. By choosing the third air chamber,
It is possible to correct only the magnification while keeping the image plane constant. It can be expressed by the formula: (2) ΔP _I (ΔX ₁ + ΔX ₂ + ΔX ₃ ) + ΔP ΔXp = 0 so that only ΔP _I changes the pressure in the connecting space of the three air chambers. Give it. At this time, regarding the change of the image plane, ΔP _I (ΔZ ₁ + ΔZ ₂ + ΔZ ₃ ) = 0 holds, and there is no change of the image plane.

On the other hand, when the two air chambers are integrally pressure-controlled, the amount of change in the imaging plane per unit pressure in each air chamber Δ
If two air chambers are selected so that Z ₁ and ΔZ ₂ cancel each other, it is possible to correct or finely adjust only the magnification without changing the image plane. That is, with respect to the variation of the image plane, ΔP _I (ΔZ ₁ + ΔZ ₂ ) = 0 is almost maintained, while the variation of magnification is (3) ΔP _I (ΔX ₁ + ΔX ₂ ) + ΔPΔ By satisfying Xp = 0, it is possible to independently perform magnification correction.

Therefore, as described above, by communicating at least two air chambers and integrally controlling the pressure, it is possible to further increase the correction amount for a specific optical performance,
Further, depending on how to select the air chamber, it is possible to independently correct only a specific optical performance.

However, in each of the above cases, even if only the magnification, for example, of the optical performances can be corrected independently, it is not possible to simultaneously correct the magnification and other optical performances, such as fluctuations of the image plane. In order to simultaneously correct both the magnification and the image plane, it is necessary to provide another air chamber for pressure control. Therefore, as described above, the two air chambers are communicatively coupled to each other to integrally control the pressure, and further the fourth air chamber is shut off from the outside air to separately control the pressure. When the magnification change amount due to the unit pressure change in the fourth air chamber is ΔX ₄ , the image plane change amount is ΔZ _4, and the pressure control amount of the fourth air chamber is ΔP _II , By simultaneously changing the pressures of the two combined air chambers by ΔP _I and the pressure of the fourth air chamber by ΔP _II so as to satisfy the above two conditions at the same time, It is possible to simultaneously correct the fluctuations ΔXp and ΔZp of both the image plane and the image plane. With respect to the fourth air chamber, the correction amount can be increased in the same manner as the above-described two air chambers by communicating with the remaining other air chambers and coupling with the other air chambers. By combining optical performance, for example air chambers that can cancel a certain aberration, it is possible to achieve correction of the magnification and the image plane without changing the aberration.

In addition to the magnification and the image plane, in order to simultaneously correct other optical performances such as spherical aberration, coma aberration, field curvature or distortion, the combined air chamber and the fourth chamber In addition to the above air chamber, an air chamber whose pressure can be controlled may be additionally provided. That is, in order to simultaneously correct three of the optical performances, three pressure control spaces independent of each other may be provided. And
Generally, a number of pressure control spaces equal to the number of optical performances to be corrected may be provided independently.

The factors that cause variations in optical performance such as variations in the magnification of the projection lens and variations in the image plane are not only atmospheric pressure but also environmental temperature outside the lens barrel, humidity, and temperature rise due to exposure energy entering the projection lens. , And so on. The magnification change amount caused by each of these elements changing by a unit amount is ΔXq, ΔXr, ΔXs, and the image plane change amount is ΔZq, ΔZr, ΔZs, respectively. The amount of change is △ Q, △ R, △ S
And the pressure control amount ΔP _I of the two connected air chambers and the pressure control amount ΔP _II of the fourth air chamber, By satisfying both of the conditions, it is possible to simultaneously correct both the magnification and the image plane. Needless to say, in the case of correcting only one of the magnification and the image plane, pressure control may be performed so as to satisfy only one of the above expressions. Also,
In this case as well, the two air chambers connected to each other may be further communicated with another air chamber to integrally control the pressure, or the fourth air chamber may also be communicated with the other air chamber to integrally pressurize. It is possible to control.

Hereinafter, the present invention will be described based on examples of the present invention. FIG. 1 is a lens arrangement diagram showing an example of a projection objective lens used in a stepper, and a predetermined pattern on a reticle (R) is reduced and projected onto a wafer (W) by this objective lens. In the figure, rays showing the conjugate relation of the on-axis object point between the wafer and the reticle are shown. This objective lens is composed of a total of 14 lenses in order from the reticle (R) side, L ₁ , L ₂ ... L ₁₄ , and is arranged between the reticle (R) and the wafer (W) on the reticle side. A total of 15 air gaps are formed in order from a, b, c ..., O. Table 1 shows the specifications of this objective lens. However, r is the radius of curvature of each lens surface,
D is the center thickness and air gap of each lens, and N is i of each lens.
It represents the refractive index for a line (λ = 365.0 nm), and the leftmost number in the table represents the order from the reticle side. Further, D ₀ represents the distance between the reticle (R) and the frontmost lens surface, and D ₃₁ represents the distance between the final lens surface and the wafer (W).

Now, in this objective lens, if the atmospheric pressures of the air intervals a, b, ... O are changed by +137.5 mmHg, respectively,
The relative refractive index of each air space changes to 1.00005, and the change of magnification and the change of the image plane, that is, the conjugate plane with the reticle (R) at this time are as shown in Table 2. However, change in magnification ΔX
Is 5.66 from the optical axis when there is no pressure fluctuation on the image plane.
An image point formed at a position separated by mm represents the amount of movement in μm after the change in atmospheric pressure at each air interval. In this case, the case where there is no fluctuation in atmospheric pressure, that is, the case where the image is projected larger on the image plane, that is, the predetermined wafer surface (enlargement) is shown as a plus sign. Further, the change ΔZ of the image plane is shown as the change of the image formation point on the axis, and the case of moving away from the objective lens is shown as a positive sign. Both values are in μm.

From Table 2 above, first, regarding the amount of change in magnification ΔX,
It can be seen that the variation amounts of the fourth space d, the fifth space e, and the sixth space f are large negative values. Therefore, if these fourth, fifth, and sixth spaces d, e, and f are cut off from the outside air and connected to form a combined air chamber, a considerably large correction value can be obtained, and pressure control for magnification correction can be obtained. The amount can be reduced. Next, with respect to the image plane variation amount ΔZ, the variation in the fourth, fifth, and sixth spaces is the largest, and according to the integrated pressure control of these spaces, the image plane is relatively small. It can be seen that the pressure control amount can be largely corrected. Then, it was found that the tenth space j, the eleventh space k, and the twelfth space l also greatly influence the fluctuation of the image forming plane.
It is found that the imaging plane can be easily corrected by blocking the 11th and 12th spaces j, k, l from the outside air and connecting them to form a combined air chamber. Further, regarding the fluctuation of the image plane, it is found that the signs of the fluctuation amounts in the first space a and the second space b are different from each other, the absolute values thereof are substantially equal to each other, and they can be canceled out from each other. The variation of the image plane of the
It can be seen that the combination with the 15th space o can almost cancel each other, and the fluctuations in magnification due to the fourteenth space and the fifteenth space can be canceled each other though they are relatively small values. Therefore, the fourth, fifth and sixth spaces d, e, f are pressure-controlled as an integral coupling space, and the tenth, eleventh and twelfth spaces j, k,
By separately controlling the pressure as l as an integral coupling space, both the magnification and the image plane can be corrected at the same time. At this time, the first space a and the second space b, and the seventh space g and the fourteenth and fifteenth spaces n and o can cancel each other's fluctuations, so that the pressure fluctuates with the atmospheric pressure. , The third space c as the remaining space, the eighth space h, the ninth space
It is desirable that the space i and the thirteenth space m are closed spaces that are shielded from the atmosphere so that fluctuations due to them are not generated.

FIG. 2 is a schematic configuration diagram of a projection optical device capable of magnification correction and image plane correction by performing pressure control of the air chamber as described above in two spaces. The projection objective lens (1) reduces and projects the pattern on the reticle (R) uniformly illuminated by the illumination device (2) onto the wafer (W) placed on the stage (3). Projection objective lens (1)
Three air chambers (40, 50, 60) corresponding to the fourth space d, the fifth space e and the sixth space f shown in FIG. The pressure is cut off and the pressure is controlled through the pipe (11) as the first pressure control space. In addition, the three air chambers (100, 110, 120) corresponding to the tenth space j, the eleventh space k, and the twelfth space l are connected by the communication part (21a) to be cut off from the atmosphere, and the pipe is used as the second pressure control space. The pressure is controlled through (21). Further, the air chambers corresponding to the third space c, the eighth space h, the ninth space i and the thirteenth space m shown in FIG. 1 are air chambers (30,80,90,130) sealed to the atmosphere. Is configured as. The space where the pressure changes with the atmospheric pressure is omitted from FIG. 2 in order to avoid complication of the drawing. The first and second pressure control spaces are connected by pipes (11, 21) to pressure controllers (12) and (22) provided outside the objective lens, respectively.
Then, each pressure controller (12, 22) is constantly supplied with air of a constant pressure from the pressurized air supplier (4) through the filters (13) and (23), and required by the exhaust device (8). Is exhausted accordingly. On the other hand, pressure sensors (14) and (24) for detecting the internal pressure of each air chamber are provided on the side surface of the air chamber, and the output signal is sent to the computing unit (5).
The measurement value of atmospheric pressure, the temperature outside the projection lens barrel, the humidity, and the temperature inside the barrel are input to the computing unit (5) from the measuring unit (6) and the temperature sensor (7) in the barrel. Computing unit (5)
Are the magnification changes per unit pressure in the air chamber in each pressure control space △ Xd, △ Xe, △ Xf; △ Xj, △ Xk, △ Xl and the imaging plane changes △ Zd, △ Ze, △ Zf; ΔZj, ΔZk, and ΔZl are stored in advance. Further, the calculator (5) has a magnification variation ΔXp and an imaging plane variation ΔZp of the objective lens caused by a unit pressure variation of atmospheric pressure, and a magnification variation accompanying a unit amount variation of temperature and humidity around the lens barrel. Amount and image plane variation, ΔXq, ΔXr; ΔZ
In addition, q, ΔZr, the amount of change in magnification due to the temperature change of the objective lens due to the exposure energy, and the amounts of change in image plane ΔXs, ΔZs are also stored. The arithmetic unit (5) uses the signals from the measuring unit (6) and the sensor (7) to change the atmospheric pressure change amount ΔP, the temperature around the lens barrel and the humidity change amounts ΔQ, ΔR, and the exposure energy. The temperature change amount ΔS of the objective lens is detected, and the pressure change amounts ΔP _I and ΔP _II necessary for each pressure control space to satisfy both conditions such as the above-mentioned formula (5) are calculated. In detail, the conditions to be satisfied in this embodiment are:
Magnification fluctuation: △ P _I (△ Xd ＋ △ Xe ＋ △ Xf) ＋ △ P _II (△ Xj ＋ △ Xk ＋ △ Xl) ＋ △ P △ Xp + △ Q △ Xq + △ R △ Xr + △ S △ Xs = 0 Regarding the surface fluctuation, △ P _I (△ Zd + △ Ze + △ Zf) + △ P _II (△ Zj + △ Zk + △ Zl) + △ P △ Zp + △ Q △ Zq + △ R △ Xr + △ S △ Xs = 0 . Here, ΔXp and ΔZp are the sums of the respective changes due to air that fluctuates with atmospheric pressure, and ΔXp = △ Xa + △ Xb + △ Xg + △ Xn + △ Xo △ Zp = △ Za + △ Zb + △ Zg + △ Zn + It is expressed as ΔZo. Each pressure controller (12, 22) determines the pressure in each control space by the signal from the arithmetic unit corresponding to the pressure change amount ΔP _I and ΔP _II required for each pressure control space to satisfy these conditions. Control. In this way, for each element that affects the optical performance of the projection lens, a constant magnification and image plane position are always maintained, and high-precision matching as a stepper is stably achieved.

In the above embodiment, the fourth, fifth and sixth spaces d, e, f and the tenth, eleventh and twelfth spaces are integrally controlled as the air chambers.
Although three lens intervals of j, k, and l are adopted, the number of air chambers for integrally controlling pressure and which interval is adopted are not limited to this. It may be appropriately determined depending on the optical performance to be performed. For example, in the above-described embodiment, further, based on the data on the pressure change shown in Table 1, the magnification fluctuation amounts in the third space c and the fourth space d can almost cancel each other. It is also possible to control the pressure by connecting the two spaces of the fifth and sixth spaces e and f so that the pressure can fluctuate with the atmosphere. Further, the image plane variation amount of the ninth space i is
Since the tenth space j and the thirteenth space m can be almost offset by the combination, the ninth space i, the tenth space j, and the thirteenth space m are also configured to change the pressure together with the atmosphere, and the eleventh space k and the twelfth space Space l
It is also possible to communicate with and control the pressure. If at least two air chambers that integrally control the pressure are adjacent to each other, it is advantageous in that the pressure is kept uniform, and the structure of the lens barrel is advantageous, but it is not necessary to limit the adjoining air chambers.

In the above embodiment, the signal from the pressure sensor provided in each air chamber is fed back to the pressure controller via the arithmetic unit, and the pressure controller is always operated. Human reading the measured value,
It is also possible to calculate a pressure change required for each air chamber and manually operate each pressure controller as needed.

As described above, if there are at least two spaces in the optical path of the projection optical system in which the atmospheric pressure can be controlled independently, changes in both the projection magnification and the image plane position can be controlled. At this time, move the lens element in the projection lens in the optical axis direction,
If the technique of changing the distance between the reticle and the projection lens is used, two or more spaces for controlling the atmospheric pressure are not necessarily required. Further, when the stepper is provided with a function of detecting and following a change in the position of the image plane, the atmospheric pressure control of the space may be performed only for one space by paying attention to only the change in magnification.
Regarding the space where the atmospheric pressure is not actively controlled, it is desirable to seal the space with a large amount of change to keep the atmospheric pressure constant. In the above embodiment, the third space c, the eighth space h, the ninth space i, and the thirteenth space. Sealing the space m is effective from this viewpoint. The first space a and the fifteenth space o are spaces between the projection lens and the reticle and between the projection lens and the wafer, respectively, and it is generally difficult to shield them from the atmosphere. In this respect, as in the above embodiment, it is better not to seal if it can be almost canceled by the combination with the second space b and the fourteenth space n.

As in the embodiment shown in FIG. 2, a specific lens interval in the projection objective lens is formed in an air chamber that is shielded from the outside air, and the pressure in this air chamber is controlled to finely adjust the magnification. However, there are various methods of operating such a magnification fine adjustment means. First, as in the embodiment shown in FIG. 2, the factors affecting the magnification change of the stepper and the degree of the influence are checked in advance, and the variation amount of each factor (for example, the environment) is measured without directly measuring the projection magnification. This is a method of measuring the temperature change and the atmospheric pressure fluctuation amount), predicting the generated magnification change amount, and operating the magnification fine adjustment means. In this case, it is desirable to configure a servo system that measures each influencing element in real time and automatically adjusts the magnification immediately as shown in FIG. 2, but it is possible to manually adjust the magnification based on the measured value. is there.

It should be noted that, instead of directly measuring the temperature change due to the energy accumulated in the objective lens, the relationship between the exposure time and the continuous operation time and the change in magnification is investigated in advance by experiments and calculations, and the exposure time and the continuous operation time are calculated. The information may be fed back to the magnification fine adjustment means.

Further, the stepper may be provided with a projection magnification measuring function, and the measurement result may be fed back to the magnification fine adjusting means. If the magnification can be measured in real time, it is possible to use a servo system that immediately adjusts the magnification. If the measurement requires a long time, the measured value may be displayed once, and the magnification may be manually adjusted based on the value. It is also easy to set up a sequence in which the magnification is adjusted based on the measured value and the magnification is rechecked. Since the projection magnification can be known by actually exposing the wafer with a stepper and measuring the wafer, this information can also be fed back to the magnification adjusting means.

By the way, N ₂ , O ₂ , CO contained in air as atmospheric pressure
Only the total pressure has been handled without considering the partial pressure of each gas such as ₂ , H ₂ O. However, since it is important to control the refractive index of air in the present invention, normally, only N ₂ is used instead of air, or the partial pressure of each gas is controlled under a constant total pressure to change the refractive index of air. It is naturally included in the present invention to do so. The present invention provides a method that allows fine adjustment of the magnification, and it is obvious that it is useful not only for keeping the magnification constant but also for changing the magnification consciously.

(Effects of the Invention) As described above, according to the present invention, it becomes possible to finely adjust the optical performances such as the projection magnification of the stepper and the image plane, or independently correct the performances, so that the environmental conditions of the machine can be prevented from changing. It is also possible to provide a stepper that contributes greatly to the improvement of VLSI productivity by maintaining high mating accuracy.

[Brief description of drawings]

FIG. 1 is a lens structure diagram of a projection objective lens for a stepper according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an embodiment of a projection optical device according to the present invention. (Explanation of symbols of main parts) 1 ... Projection objective lens, 30, 40, 50, 60, 80, 90, 100, 110, 12
0,130 ... Air chamber, 12,22 ... Pressure controller, R ... Reticle, W ... Wafer

Claims (3)

[Claims] 1. A projection optical system for projecting and exposing a pattern on a reticle uniformly illuminated by an illuminating means onto a photosensitive substrate with desired imaging performance, and a plurality of optical elements constituting the projection optical system. A plurality of air intervals selected from among the plurality of air intervals, and adjusting means for adjusting the refractive index of the gas in the selected air intervals, the external air factor of the projection optical system. In a projection optical apparatus configured to correct the fluctuation of the imaging performance, a magnification fluctuation rate and a fluctuation of an imaging plane position which occur when the gas refractive index of one air space in the projection optical system is changed by a predetermined amount. When the ratio is obtained for each air interval, one of the sum of the magnification fluctuation ratio and the sum of the fluctuation ratios of the imaging plane positions is set to substantially zero, and the other sum is finite. Some air gaps such as And a projection optical system in which a communicating portion that communicates the specified several air gaps as a combined air chamber is formed; further, among the variation of the magnification of the projection optical system and the variation of the image plane position, Measuring means for measuring a variation in which the total takes a finite value, or a variation in an external factor causing the variation; magnification variation of the projection optical system according to a measurement value measured by the measuring means And a control means for controlling the adjusting means so as to simultaneously change the refractive index of the gas in the combined combined air chamber so as to correct either of the change of the image plane position and the change of the image plane position. Projection optical device. 2. The measuring means includes a sensor for measuring any one of atmospheric pressure change, temperature change, and lens barrel temperature change of the environment in which the projection optical system is installed,
The control means includes an arithmetic circuit that calculates the pressure correction amount of the gas in the connected combined air chamber based on the measurement value from the sensor, and the adjusting means so as to obtain the calculated pressure correction amount. The apparatus according to claim 1, further comprising a servo control system for feedback control. 3. The measuring means has means for detecting information relating to exposure energy accumulated in the projection optical system during projection exposure of the reticle pattern onto a photosensitive substrate, and the control means has the information. The device according to claim 1, wherein the adjusting means is controlled in accordance with