WO2015169012A1

WO2015169012A1 - Euv photoetching device and exposure method therefor

Info

Publication number: WO2015169012A1
Application number: PCT/CN2014/085135
Authority: WO
Inventors: 郑乐平; 许琦欣; 王帆; 吴飞
Original assignee: 上海微电子装备有限公司
Priority date: 2014-05-06
Filing date: 2014-08-26
Publication date: 2015-11-12
Also published as: CN106255922B; CN106255922A; CN105093836A; CN105093836B

Abstract

An EUV photoetching device and an exposure method therefor. A mask table (300) of the device bears a plurality of reflection type masks (400a, 400b), wherein while one reflection type mask (400a) at an exposure position conducts exposure, the other reflection type mask (400b) at a measurement position can conduct facial forming and position measurement simultaneously. When a plurality of batches of silicon chips are exposed, the time for facial forming and position measurement can be saved, thereby improving the productivity. The mask table (300) can also bear a plurality of identical reflection type masks, and silicon chips are exposed by using a manner of switching masks alternately, so that by means of continuously switching the reflection type masks, the occurrence of the situation where the image quality is impaired, which is caused by the thermal deformation of the reflection type masks after being exposed for a period of time, due to the fact that heat dissipation in a high vacuum environment is difficult can be avoided.

Description

Technical field

The present invention relates to the field of lithography, and more particularly to an EUV lithography apparatus and an exposure method thereof. Background technique

The projection exposure apparatus is used for a projection exposure of a circuit pattern on a reticle through a projection optical system, and the circuit pattern can be projected onto a silicon wafer of an integrated circuit at a magnification of a certain magnification or reduction. The development of integrated circuits follows the "Moore's Law". With the rapid development of IC manufacturing technology, IC integration is gradually increasing, and the wavelength of light used in projection exposure devices is gradually decreasing. The current mainstream lithography technology uses 193nm (Deep UV; DUV). ) The wavelength of the laser. Driven by process innovations such as immersion technology, double exposure and multiple exposures, the lithography limit that can be achieved by DUV wavelengths is gradually approaching. It is expected that the user cost of using 193nm exposure devices will be greatly improved at the nanonodes. The extreme ultraviolet (EUV) light exposure device (EUVL) with a wavelength of 13.5 nm will show a greater competitive advantage and will undoubtedly become the first choice for next-generation lithography. A typical configuration of the EUV exposure apparatus is as shown in FIG. 1, and includes: a base frame 10, a mask stage 20, a measurement frame 30, a surface sensor 31, an EUV light source 50, an illumination system 42, a projection system 41, and a stone substrate. 60.

Since the existing materials are highly absorptive to the ultraviolet (13.5 nm) light energy, the EUVL illumination and projection system requires a high degree of vacuum, and all lenses use reflection, including reflective masks. . Therefore, the illumination beam is not perpendicular to the mask substrate, and the incident angle is generally 6 degrees, whereby the local shape, tilt, and material properties of the mask greatly affect the image quality. In addition, according to the nature of the reflective optical system, in order to balance the large field of view and image quality, the system is more inclined to design a circular field of view (refer to US Patent No. 6225027B1 EUVL system in 2001). The oblique principal ray angle plus the annular field of view results in non-telecentricity of the imaging system. The so-called non-telecentricity means that the vertical deviation of the mask from the optimal object plane can cause the engraving error of the imaging system. Will exceed User-allowed range (because 193nm lithography equipment typically uses a double telecentric design without this type of problem). In order to control this error, the control accuracy of the mask height should be kept at 10 to 20 nm (corresponding to the silicon wafer height control precision of the conventional 193 nm lithography equipment), so to solve the problem that the EUV lithography system is not telecentric. In the case of the registration error, it is necessary to increase the mask surface sensor 31 which measures the relative height distribution of the absorption layer on the mask surface over the entire mask surface.

Since the particle mask is inevitably present in the mask table itself or on the back surface of the mask, the partial shape of the mask after being uploaded to the mask table changes. Therefore, it is necessary to measure the position of each point on the mask surface and its corresponding topography. During the operation of the system, through the "acquisition of the correction amount - calculation of the adjustment amount - the implementation of the adjustable component, the overlay error control. The timing of the measurement is selected after the mask is loaded into the mask table, before the wafer exposure is officially performed. The measured data is transmitted to the control module to adjust the height of the mask maglev. The adjustment accuracy of the mask height mainly depends on the measurement accuracy of the magnification and the accuracy of the laser interferometer. This requires real-time coordination of multiple coupling systems. And have accurate and fast feedback processing time.

In today's exposure devices, continuous batch operation is required to improve the yield. The comprehensive local surface measurement of the loaded mask in advance inevitably affects the yield, and how to solve the EUV lithography environment, the mask surface Type calibration, mask thermal effect deformation in high vacuum environments, double or multiple exposure issues, these issues will affect the lithography yield to varying degrees.

Therefore, the following technical problems exist in the prior art:

1. For EUV lithography multi-batch continuous exposure, before each batch of the first wafer is exposed, it is necessary to exchange the mask at the exchange position, measure the mask surface at the measurement position, and then measure the exposure surface. Exposure is performed, especially when performing a double exposure or multiple exposure process, each mask switching and subsequent operation measurements are performed serially, and the yield is therefore affected.

2. In the EUV high vacuum environment, the mask heat dissipation is more difficult. When the mask is continuously exposed, the mask absorption layer is deformed by heat, which affects the image quality. It is necessary to wait for the temperature reduction treatment to affect the yield.

3, EUV lithography system is particularly sensitive to the environment, when you need to use the calibration mask to calibrate the system, mask replacement and surface measurement take time, affecting the yield. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide an EUV lithography apparatus and an exposure method thereof for improving the yield of an EUV lithography apparatus.

Another object of the present invention is to provide an EUV lithography apparatus and an exposure method thereof for solving the problem that a mask is subjected to thermal deformation for a long period of time.

In order to achieve the above object, a first aspect of the present invention provides a lithographic apparatus and an exposure method thereof, the apparatus comprising an EUV light source, an illumination system, a projection system, and a workpiece stage, the apparatus further comprising: a mask stage, Moving over the projection system, the mask table has a first stage and a second stage on a side of the first stage; and a first measurement system disposed on one side of the projection system, wherein The first stage of the mask stage is configured to carry a first reflective mask and to cause the EUV to emit EUV when the mask stage is moved to a first position relative to the projection system The light is irradiated onto the workpiece stage through the illumination system, the first reflective mask, and the projection system; wherein the second stage of the mask stage is configured to carry a second reflective mask, and the first The position of the measurement system is set such that when the mask table is in the first position, the first measurement system is capable of measuring the shape and position of the second reflective mask.

Further, the first measurement system includes first and second sensors for measuring a positional relationship of the reflective mask with respect to a mask table, and a plurality of shapes for measuring the reflective mask. A third sensor.

Further, the plurality of third sensors are located between the first sensor and the second sensor. Further, the first and second sensors and the plurality of third sensors are arranged in a linear array, and the length of the linear array is greater than or equal to the length of the reflective mask.

Further, the position of the first measuring system is set such that when the mask table is in the first position, the first measuring system is opposite to the second reflective mask.

Further, a plurality of stage markings are disposed on the first and second stages.

The exposure method according to the first aspect of the present invention is performed by the above lithographic apparatus, and while the silicon wafer on the workpiece stage is exposed using the first reflective mask carried by the first stage, the first measurement The quantity system measures at least one of a face shape and a position of the second reflective mask carried by the second stage.

A second aspect of the invention proposes a lithographic apparatus and an exposure method thereof, the apparatus being added to the other side of the first stage on the mask stage based on the apparatus according to the first aspect of the invention a third stage, and the device further includes a second measurement system disposed on the other side of the projection system, wherein the third stage is configured to carry a third reflective mask, and The position of the second measurement system is set such that when the mask table is in the first position, the second measurement system is capable of measuring the shape and position of the third reflective mask.

Further, the position of the second measuring system is set such that when the mask table is in the first position, the second measuring system is opposite to the third reflective mask.

The exposure method according to the second aspect of the present invention is performed by the above lithography apparatus, and the first measurement system is simultaneously exposed to the silicon wafer on the workpiece stage using the first reflective mask carried by the first stage Measuring at least one of a face shape and a position of a second reflective mask carried by the second stage and/or a face shape of the third reflective mask carried by the second measuring system to the third stage At least one of the locations is measured.

A third aspect of the invention proposes a further lithographic apparatus and an exposure method thereof, the apparatus adding a second measurement system on the other side of the projection system based on the apparatus according to the first aspect of the invention When the mask table is moved to a second position relative to the projection system, causing the

EUV light emitted by the EUV light source is irradiated onto the workpiece stage through the illumination system, the second reflective mask carried by the second stage, and a projection system; the position of the second measurement system is set to be The second measurement system is capable of measuring the face shape and position of the first reflective mask carried by the first stage when the die stage is in the second position.

The exposure method according to the third aspect of the present invention is carried out by using the above lithographic apparatus, and while exposing the silicon wafer on the workpiece stage using one of the first and second stages of the reflective mask, A respective one of the first and second measurement systems measures at least one of the face shape and position of the reflective mask carried by the other of the first and second stages. Compared with the prior art, the beneficial effects of the present invention are mainly embodied in: Since the mask table carries a plurality of reflective masks, the reflective mask in the exposure position is exposed while another reflective mask in the measurement position The mold can simultaneously perform surface and position measurement. When multi-batch wafer exposure, it can save surface and position measurement time, and use the measured surface and position data of the reflective mask to perform feedforward control of mask height. In the case of ensuring the precision of the engraving, the exposure feedback adjustment time is reduced, so that the yield can be improved.

In addition, the mask table can also carry a plurality of identical reflective masks, and the masks are alternately used to switch the wafers by switching the masks. By continuously switching the reflective masks, heat dissipation in a high vacuum environment can be avoided. This causes the thermal deformation of the reflective mask after a period of exposure to cause image quality damage.

Further, since under certain process conditions, the exposure wafer is required to be double-exposed or multi-exposure, a multi-load mask stage can be conveniently accommodated in an EUV lithography apparatus. Since multiple reflective masks can be exchanged at one time, the reflective mask exchange time can be saved for multiple batches of continuous exposure; since a single mask table is used to carry multiple reflective masks, a set of mask tables can be shared. Positioning the measurement system, the multi-load mask stage eliminates the need for repetitive measurement and saves space and cost. DRAWINGS

1 is a schematic structural view of an EUV device in the prior art;

2 is a schematic structural view of an EUV device according to Embodiment 1 of the present invention;

3 is a schematic structural view of a reflective mask and a mask stage according to Embodiment 1 of the present invention; FIG. 4 is a schematic cross-sectional view of the combined surface sensor according to Embodiment 1 of the present invention;

5 is a schematic structural view of an EUV device according to Embodiment 2 of the present invention;

FIG. 6 is a schematic structural diagram of an EUV device according to Embodiment 3 of the present invention. detailed description The EUV lithography apparatus of the present invention and its exposure method will be described in more detail below with reference to the accompanying drawings, in which a preferred embodiment of the present invention is shown, and it is understood that those skilled in the art can modify the invention described herein while still implementing the present invention. Advantageous effects of the invention. Therefore, the following description is to be understood as a broad understanding of the invention, and is not intended to limit the invention.

In the interest of clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail as they may obscure the present invention in unnecessary detail. It should be understood that in the development of any actual embodiment, a large number of implementation details must be made to achieve a particular goal of the developer, such as changing from one embodiment to another in accordance with the limitations of the system or related business. In addition, such development work should be considered complex and time consuming, but is only routine work for those skilled in the art.

The invention is more specifically described in the following paragraphs by way of example with reference to the accompanying drawings. Advantages and features of the present invention will be apparent from the description and appended claims. It is to be understood that the appended drawings are intended to be illustrative of the embodiments Embodiment 1

Referring to FIG. 2, in the present embodiment, an EUV lithography apparatus is proposed, comprising: an EUV light source 100, an illumination system 210, a projection system 220, a workpiece stage 700, a mask stage 300, and a measurement system.

510; wherein, the EUV lithography apparatus has an exposure position and a measurement position, the projection system 220 and the workpiece stage 700 are located at an exposure position, and the measurement system 510 is located at a measurement position; the exposure position and the measurement bit respectively mean lithography A station of the device, that is, a spatial position to be occupied by the specified process. In this embodiment, the components located at the exposure position are used to cooperate to complete the exposure process for the silicon wafer, and the components located at the measurement position are used for Work together to complete the measurement process for the mask. It should be noted that the exposure position and the measurement position are only schematically shown in the drawings of the specification, and the division of the stations may be different according to different lithographic apparatuses, and thus should not be construed as limiting the present invention. In addition, although the exposure bit and the measurement bit shown in the figure are adjacent, both of them may be interdigitated in the spatial position. The stacked, in other words, the components of the exposure position may overlap with the components of the measurement position in a spatial position as long as the implementation of the corresponding process is not affected. The mask table 300 carries a plurality of reflective masks, collectively indicated by reference numeral 400. Two reflective masks, 400a and 400b, are shown in FIG. 2, and the light emitted by the EUV light source 100 is irradiated to the workpiece through the illumination system 210, the reflective mask 400a on the mask stage, and the projection system 220. On the stage 700 (shown by the arrows in the figure), the measurement system 510 performs face and position measurements on the reflective mask 400b at the measurement level.

In the present embodiment, the EUV lithography apparatus further includes a base frame 600 and also has a switching bit. Similarly, the interchangeable bits are only schematically shown in the drawings, and are not intended to limit the present invention. The EUV light source 100, the illumination system 210, the projection system 220, the workpiece stage 700, the mask stage 300, and the measurement system 510 are all disposed within the base frame 600 at which the reflective mask 400 can be replaced.

In this embodiment, the measurement system 510 includes at least one sensor (RLS, Reticle Location-Leveling Sensor) and is fixed on the base frame 600 by a measurement frame 520 and located at the measurement position. Referring to FIG. 4, the measurement system 510 includes a first position sensor 511, a second position sensor 512, and a plurality of face sensors 513, such as eight face sensors 513, the face sensor 513 is located at the first position sensor. Between 511 and the second position sensor 512. The measuring system 510 is in a measuring position, and has a mask position measuring and a mask surface measuring function. The sensors in the measuring system 510 are arranged in a straight line, and the position measuring system composed of the first position sensor 511 and the second position sensor 512 is located in a straight line. The mask stage marks and mask marks can be captured on both sides, and the face sensor 513 is located in the center of the measurement system and can capture the mask face of the entire reflective mask 400b being measured.

In this embodiment, only one measurement system 510 is included, and is located at the measurement position. The mask table 300 carries two reflective masks 400a, 400b, and the reflective masks 400a, 400b are respectively carried by the mask stage. The 410a, 410b bearers are coupled to the mask table 300, one reflective mask 400a is in the exposure position, and the other reflective mask 400b is in the measurement position and opposite the measurement system 510.

In this embodiment, an EUV lithography exposure method is also proposed, using the EUV described above. A lithographic apparatus, the method comprising the steps of:

S100: loading the reflective masks 400a and 400b on the mask table 300 at the swapping position, and loading the silicon wafer 800 on the workpiece table 700;

S200: moving the mask table 300, moving the reflective mask 400a to the measurement position, and performing measurement on the surface and position of the reflective mask 400a using the measurement system 510;

S300: moving the mask table 300, moving the reflective mask 400a to the exposure position (where the reflective mask 400b is at the measurement position), and establishing a positional relationship between the reflective mask 400a and the silicon wafer 800;

S400: exposing the silicon wafer 800 while using the measuring system 510 to perform surface shape and position measurement on the reflective mask 400b;

S500: when the silicon wafer 800 is replaced after the exposure, the mask table 300 moves, the reflective mask 400b is moved to the exposure position, and the positional relationship between the reflective mask 400b and the replaced silicon wafer 800 is established;

S600: Exposing the replaced silicon wafer 800, and repeating the above steps until all the silicon wafers 800 are exposed.

Specifically, the exchange mask can be exchanged by the mask transfer system of the EUV lithography apparatus; the two reflective masks 400a, 400b can be simultaneously loaded and unloaded; that is, the first reflective mask 400a first Entering the measurement location; a measurement system (RLS) 510 located at the measurement location and below the first reflective mask 400a begins to measure the horizontal position and profile height of the first reflective mask 400a.

As shown in FIGS. 3 and 4, the reflective mask 400 is provided with mask marks R1, R2, R3 and

R4; the mask stage 410 is provided with mask stage marks RM1, RM2, RM3 and RM4; the measurement system marks the mask marks R1, R2, R3 and R4 and the mask stage marks RM1, RM2 ,

RM3 and RM4 identify, establish the horizontal positional relationship of the reflective mask, specifically, the mask table

The 300 is scanned back and forth in a horizontal direction, and the first position sensor 511 and the second position sensor 512 in the measurement system 510 can identify the two marks and establish a horizontal positional relationship. Measuring system

The surface sensor 513 in 510 can measure the mask height of the corresponding position of the surface of the reflective mask 400, that is, the topography relationship of the reflective mask 400 is obtained, and the number of scans is determined by the surface measurement accuracy. The first position sensor 511 and the second position sensor 512 are used to determine the horizontal position of the reflective mask 400 and the mask stage 410.

The reflective mask 400a is loaded into the exposure position after the scanning of the first reflective mask 400a is completed by the above method, as shown in FIG. The reflective mask 400a is then aligned, which measures the mask stage marks RM1, RM2, RM3, and RM4 on the mask stage 410a by an image sensor (not shown) on the workpiece stage 700. Calculate the positional parameters of the spatial image of the reflective mask 400a, establish a spatial positional relationship between the reflective mask 400a and the exposure field of the silicon wafer 800, and adjust various factors such as the magnification adjustment amount (ie, obtain a height change of the reflective mask 400a). The amount of change in the engraving error caused).

When the silicon wafer 800 is exposed, the reflective mask 400a at the exposure position at this time establishes the positional relationship with the silicon wafer 800, and starts to continuously expose the exposure field of the silicon wafer 800, which is measured by the measurement position before the call. The surface data of the reflective mask 400a combines the scanning position and the optimal adjustment strategy to feed forward the attitude of the mask table 300, thereby calibrating the overlay error of the exposure field in real time. At this time, another reflective mask 400b is in the measurement position, and the measurement system 510 can perform alignment and global Coarse Grid Measure on the other reflective mask 400b. The coarse measurement is used to obtain the mark position information and the preliminary face shape information of the other reflective mask 400b, and transmit the measured face shape data of the other reflective mask 400b to the server end as the other The reflective mask 400b feeds back the basis of aberration calibration during scanning exposure.

After the scanning exposure of a silicon wafer 800 is completed, the silicon wafer 800 enters an exchange state, at which time the reflective mask 400a in the exposure position is in an idle state, and the other reflective mask 400b in the measurement position performs a local grid point at this time. a local fine Grid Measure, and passing the measured face data of the other reflective mask 400b to the server as the other reflective mask

The basis for the calibration of the overlay error during 400b feedforward scanning exposure. Therefore, another reflective mask for 400b

The time for the face and position measurement of the 400b is shared with the exposure of the silicon wafer 800 and the replacement of the silicon wafer 800. After the exposure of the batch of wafers 800 is completed, the mask needs to be replaced to continue exposing the next batch of wafers 800, then the other reflective mask 400b enters the exposure position to initiate subsequent exposure. Waiting After the second batch of wafers 800 are exposed, the mask stage 300 enters the exchange location and is exchanged with the used reflective masks 400a, 400b using the third and fourth reflective masks. This cycle is repeated until all of the silicon wafers 800 have been exposed.

It should be noted that the other reflective mask 400b and the reflective mask 400a may have the same or different mask patterns. As mentioned in the background art, in EUV high vacuum environment, the mask heat dissipation is more difficult. When a mask is continuously exposed, the mask absorption layer is deformed by heat, which affects the image quality, and needs to wait for the temperature reduction treatment to affect the yield. . By using the lithographic apparatus of this embodiment, it is possible to load two masks having the same pattern and alternately perform exposure, thereby effectively avoiding the problem of heat deformation caused by continuous exposure of the same mask. It not only saves the time required for cooling treatment, but also improves the image quality. Embodiment 2

Referring to FIG. 5, in the embodiment, an EUV lithography apparatus is proposed. Based on the first embodiment, two measurement systems 510a and 510b are disposed, which are respectively located at the first measurement position and the second measurement position. The first measurement bit and the second measurement bit are respectively located at two sides of the exposure position, and the mask table 300 carries three reflective masks, 400a, 400b, 400c, respectively, and each of the reflective masks 400a, 400b, 400c are connected to the mask table 300 by corresponding mask stages 410a, 410b, 410c, one reflective mask 400a is in the exposure position, and the other two reflective masks 400b, 400c are respectively located in the first measurement The bit and the second measurement bit are opposite the two measurement systems 510a, 510b of the first measurement bit and the second measurement bit.

The EUV lithography apparatus and the EUV lithography exposure method are the same as those in the first embodiment. For details, refer to the first embodiment, and details are not described herein again.

Different from the first embodiment, after the first batch of the silicon wafer 800 is exposed, it is necessary to continue to expose the next batch of the silicon wafer 800, and the reflective mask can be located at the first measurement position or at the second measurement position. The die 400b (or 400c) enters the exposure position and begins subsequent exposure. Waiting for the second batch of wafers 800 to be exposed, and continuing to expose the remaining one of the measurement sites of the reflective mask 400c (or 400b) Enter the exposure position and start the subsequent exposure. Therefore, the EUV lithography apparatus proposed in this embodiment can realize the exchange of three reflective masks 400. Embodiment 3

Referring to FIG. 6, in the embodiment, an EUV lithography apparatus is proposed, which includes two measurement systems 510a and 510b and two measurement bits, and the two measurement bits are a first measurement bit and a second measurement bit, respectively. , located on both sides of the exposure position.

However, in the present embodiment, the mask table 300 only carries two reflective masks 400a, 400b, and the mask table 300 can be horizontally moved in the direction of the arrow in FIG. 6, so that the two reflective masks 400a can be made. , 400b switches between the first measurement bit, the exposure bit, and the second measurement bit.

The rest of the device and the exposure method are the same as those in the first embodiment, and are not described here. For details, please refer to the first embodiment.

In summary, in the EUV lithography apparatus and the exposure method thereof provided by the embodiments of the present invention, since the mask stage carries a plurality of reflective masks, the reflective mask in the exposure position is exposed while being in the measurement position. A reflective mask allows simultaneous face and position measurements. When multiple batches of wafers are exposed, mask surface and position measurement time can be saved, using the measured face and position data of the reflective mask. The feedforward control of the mask height reduces the exposure feedback adjustment time while ensuring the engraving precision, so the yield can be improved; the reflective mask of the multi-mask stage can be quickly switched by switching the mask The wafer exposure is continued on another identical reflective mask. By continuously switching the reflective mask, it is difficult to avoid heat dissipation in a high vacuum environment, resulting in thermal deformation of the reflective mask after exposure for a period of time, resulting in image quality damage. The situation happened.

Further, the multi-stage mask can continue to expose the wafer on another identical reflective mask relatively quickly by switching the reflective mask, by continuously switching the reflective mask.

The EUV lithography apparatus utilizes an increase in efficiency, thereby reducing the total cost of ownership for the EUV lithography apparatus; since under certain process conditions, it is necessary to use double exposure or multiple exposure methods for the exposed silicon wafer, the multi-load mask stage is also This need can be conveniently met in an EUV lithography apparatus. Because you can pay at one time Multiple reflective masks can save reflective mask exchange time for multiple batches of continuous exposure; a set of mask table positioning measurement systems can be shared because multiple reflective masks are used to carry multiple reflective masks Therefore, the multi-load mask table eliminates the need for repeated measurement processes and saves space and cost.

The above are only the preferred embodiments of the present invention and do not limit the invention in any way. Any person skilled in the art can make any equivalent changes or modifications to the technical solutions and technical contents disclosed in the present invention without departing from the technical solutions of the present invention. The content is still within the scope of protection of the present invention.

Claims

Rights request

1. A lithography device, including an EUV light source, an illumination system, a projection system and a workpiece stage, characterized in that the device also includes:

The mask stage is movable above the projection system, and the mask stage has a first stage and a second stage located on one side of the first stage; and

a first measurement system, located on one side of the projection system,

Wherein, the first stage of the mask stage is used to carry a first reflective mask, and when the mask stage moves to a first position relative to the projection system, the EUV light source The emitted EUV light passes through the illumination system, the first reflective mask and the projection system and is irradiated onto the workpiece stage; wherein, the second stage of the mask stage is used to carry a second reflective mask, and the The position of the first measurement system is set such that when the mask stage is located at the first position, the first measurement system can measure the surface shape and position of the second reflective mask.

2. The device of claim 1, wherein the first measurement system includes first and second sensors for measuring the positional relationship of the reflective mask relative to the mask stage, and A plurality of third sensors measuring the surface shape of the reflective mask.

3. The device of claim 2, wherein the plurality of third sensors are located between the first sensor and the second sensor.

4. The device of claim 3, wherein the first and second sensors and the plurality of third sensors are arranged in a linear array, and the length of the linear array is greater than or equal to the reflective mask. length.

5. The device of claim 1, wherein the position of the first measurement system is set such that when the mask stage is at the first position, the first measurement system is in contact with the second measurement system. Reflective mask opposite.

6. The device according to claim 1, characterized in that, both the first and second stages are provided with a plurality of stage marks.

7. The device according to claim 1, wherein the mask stage also has a third stage located on the other side of the first stage, and the device further includes a second measurement system, is provided on the other side of the projection system, wherein the third stage is used to carry a third reflective mask, and the position of the second measurement system is set such that when the mask stage is located When the first position is determined, the second measurement system can measure the surface shape and position of the third reflective mask.

8. The device according to claim 7, wherein the position of the second measurement system is set such that when the mask stage is at the first position, the second measurement system is in contact with the third measurement system. Reflective mask opposite.

9. The device of claim 1, wherein the device further includes a second measurement system located on the other side of the projection system; when the mask stage moves to a first measurement system relative to the projection system, In the second position, the EUV light emitted by the EUV light source is illuminated to the workpiece stage through the illumination system, the second reflective mask carried by the second stage and the projection system; the position of the second measurement system The second measurement system is configured to measure the surface shape and position of the first reflective mask carried by the first stage when the mask stage is located at the second position.

10. The device according to claim 1, wherein the first reflective mask and the second reflective mask have the same mask pattern.

11. An exposure method using the photolithography apparatus according to any one of claims 1 to 6, characterized in that the silicon on the workpiece stage is exposed to the first reflective mask carried by the first stage. While the sheet is being exposed, the first measurement system measures at least one of the surface shape and the position of the second reflective mask carried by the second stage.

12. An exposure method using the photolithography apparatus according to any one of claims 7 to 8, characterized in that the silicon on the workpiece stage is exposed to the first reflective mask carried by the first stage. While the film is being exposed, the first measurement system measures at least one of the surface shape and position of the second reflective mask carried by the second stage, and/or the second measurement system measures the third stage. At least one of a surface shape and a position of the third reflective mask being carried is measured.

13. An exposure method using the photolithography apparatus according to claim 9, characterized in that: While the silicon wafer on the workpiece stage is exposed using a reflective mask carried by one of the first and second stages, a corresponding one of the first and second measurement systems measures the first and second stages. At least one of the surface shape and the position of the reflective mask carried by the other one is measured.