JP2008252040A - Liquid-immersed exposure equipment and cleaning method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid-immersed exposure equipment effectively removing the particles attached to the inside of the equipment, and also to provide its cleaning method. <P>SOLUTION: In the liquid-immersed exposure equipment 100, a space between an projection optical system 104, and an exposure target layer are filled with a liquid, and an exposure light is irradiated to the exposure target layer via the liquid. The equipment has a bubble forming unit 112 to form bubbles in the cleaning liquid to be supplied to the fluorescent-film forming equipment 100, a controller 113 to control the bubbles formed by the bubble forming unit 112, and a particle monitor 114 to get data on the particles attached to the equipment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an immersion exposure apparatus and a cleaning method thereof.

An immersion exposure apparatus used in the semiconductor lithography process immerses liquid between the projection optical system and the wafer, thereby enabling NA (Numerical Aperture) and expansion of the depth of focus. It is expected to become a mainstream exposure apparatus in manufacturing.

However, an immersion exposure apparatus, an apparatus in which particles (contaminants) taken into the liquid from various structures that guide the wafer and the liquid come into contact with the liquid such as a projection optical system, an immersion liquid supply / recovery head, and a wafer stage. May adhere to components. The particles adhering to these parts may reach the film to be processed through the liquid or the like to contaminate the film to be processed (see, for example, Patent Document 1).

On the other hand, a method is known in which the inside of the apparatus is cleaned with a cleaning liquid containing bubbles (cavities) and particles adhering to the inside of the apparatus are removed. However, even with such a method, even fine particles inside the apparatus cannot be effectively removed, and there is a risk that a great deal of time is consumed for particle removal.
International publication WO99 / 49504

The present invention has been made to solve the above problems, and an object of the present invention is to provide an immersion exposure apparatus and a cleaning method thereof that can effectively remove particles adhering to the apparatus.

  In order to achieve the above object, an immersion exposure apparatus of one embodiment of the present invention fills a liquid between a projection optical system and a film to be exposed, and irradiates the film to be exposed with exposure light through the liquid. An immersion exposure apparatus, which generates bubbles in a cleaning liquid supplied to the apparatus, a controller for controlling bubbles generated in the bubble generator, and information on particles attached to the apparatus And a particle monitor.

According to another aspect of the present invention, there is provided a method for cleaning an immersion exposure apparatus, wherein a liquid is filled between a projection optical system and an exposure target film, and the exposure target film is irradiated with exposure light through the liquid. A method for cleaning an exposure apparatus, the step of acquiring information on particles adhering to the apparatus, the step of generating bubbles controlled based on the particle information in a cleaning liquid, and the cleaning liquid containing the bubbles inside the apparatus And a step of supplying to the apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the immersion exposure apparatus which can remove effectively the particle adhering in an apparatus, and its washing | cleaning method can be provided.

  Hereinafter, an immersion exposure apparatus and a cleaning method thereof according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an immersion type projection exposure apparatus (hereinafter referred to as an immersion exposure apparatus) according to an embodiment of the present invention.

The immersion exposure apparatus 100 according to this embodiment includes an ArF excimer laser (wavelength λ = 193 nm) light source 101 and an illumination optical system 102, and a reticle stage 103 below the illumination optical system 102. When a circuit pattern is exposed to a semiconductor substrate (film to be exposed) on which a resist film or the like is formed, a reticle that is a photomask having a mask pattern formed on the reticle stage 103 is set and exposure emitted from the light source 101 is performed. The light is condensed by the illumination optical system 102 and applied to the mask. As the light source 101, a KrF excimer laser (wavelength λ = 248 nm) or an F ₂ laser (wavelength λ = 157 nm) can be used.

A projection optical system 104 is disposed below the reticle stage 103, and a wafer stage 105 on which a semiconductor substrate is placed is disposed below the projection optical system 104. The exposure light applied to the mask is imaged on the surface of the resist film placed on the wafer stage 105 through the projection optical system 104, whereby the mask pattern formed on the mask is transferred to the resist film.

Both reticle stage 103 and wafer stage 105 can be driven in the horizontal direction. Each position is monitored by a reticle stage interferometer and a wafer stage interferometer, and is moved and controlled to a predetermined position by a reticle stage controller and a stage controller. For example, in a scan-and-repeat exposure apparatus, not all patterns on a photomask are transferred to a resist film at once, but only a predetermined range of patterns called exposure fields on a photomask and a conjugate substrate plane. Irradiated at once. The photomask on the reticle stage 103 and the substrate on the stage 105 are controlled to move in a conjugate direction at a speed ratio corresponding to the magnification of the projection optical system 104 with the exposure field as a reference, and the photomask is positioned in the exposure field. The upper pattern region is moved, and the entire pattern in a predetermined range on the photomask is projected onto the resist film. Further, in order to adjust the semiconductor substrate to a desired position / posture in accordance with the focus position, the wafer stage 105 can be driven vertically or inclined.

On the wafer stage 105 below the projection optical system 104, a fence 106 for holding a liquid (an immersion liquid or a cleaning liquid) supplied onto the wafer stage 105 is attached. At the time of exposure, an immersion liquid layer (thickness of about 100 μm) is filled in an optical path space where the substrate in the region surrounded by the fence 106 and the projection optical system 104 face each other. Thus, exposure resolution can be improved by filling and exposing the immersion liquid between the projection optical system 104 and the substrate. For example, an immersion exposure apparatus using pure water having a refractive index of 1.44 as an immersion liquid in an ArF light source is a dry exposure apparatus in which air (refractive index = 1) is filled between the projection optical system and the substrate. In comparison with this, the numerical aperture of the projection optical system is substantially 1.44 times, and the resolution can be improved.

Near the projection optical system 104, a pair of heads (an immersion liquid supply unit and an immersion liquid supply unit) for injecting the immersion liquid into the fence 106 and collecting the immersion liquid from the fence 106 are provided. (Not shown). The immersion liquid supply / recovery head performs an immersion liquid injection / recovery operation or a stop operation thereof depending on the stage drive during exposure. For example, the direction of the water flow is changed by switching the role of injection / collection of the pair of heads according to the scanning direction of the exposure light. Further, at the time of exposure, it is possible to circulate the immersion liquid filling the exposure area at any time by simultaneously operating the injection / recovery operation of the head, and the transfer pattern accuracy is deteriorated by preventing the temperature of the immersion liquid from rising. Can be prevented.

Next, the cleaning mechanism provided in the exposure apparatus 100 according to the present embodiment will be described.

Near the projection optical system 104, a cleaning liquid supply head 108 (cleaning liquid supply unit 108) that supplies a cleaning liquid 107 for cleaning the inside of the apparatus to the inside of the fence 106, and a cleaning liquid recovery head 109 (cleaning liquid) that recovers the cleaning liquid 107 from the inside of the fence 106. A recovery unit 109) is provided. After the transfer pattern is formed on the substrate by immersion exposure, cleaning is started, and the cleaning liquid supply head 108 (cleaning liquid supply unit 108) and the cleaning liquid recovery head 109 (cleaning liquid recovery unit 109) are operated to supply / recover the cleaning liquid 107 simultaneously. Then, the cleaning liquid 107 is circulated through the piping system to remove particles adhering to the apparatus components contacting the immersion liquid. Here, the apparatus constituent parts to be cleaned in particular are the projection optical system 104, the fence 106, the wafer stage 105, the immersion liquid supply unit, the immersion liquid supply unit, and the like. The functions, structures, and numbers of the cleaning liquid supply / recovery heads 108 and 109 are arbitrary and are not particularly limited.

A cleaning liquid generator 110 is connected to the cleaning liquid supply head 108 via a piping system, and the cleaning liquid 107 generated by the cleaning liquid generator 110 is supplied to the cleaning liquid supply head 108. As the cleaning liquid 107, functional water such as ozone water, ionic water, carbonated water, hydrogen water, or the like can be used. In the exposure apparatus 100 according to the present embodiment, the cleaning liquid generation unit 110 is provided outside the apparatus as shown in FIG. 1, but it may be provided inside the apparatus as a component of the apparatus.

The cleaning liquid generator 110 is connected to the cleaning liquid recovery head 109 through a piping system. A valve 118 is provided between the cleaning liquid recovery head 109 and the cleaning liquid generator 110, and the cleaning liquid 107 recovered by the head can be recovered by the cleaning liquid generator 110 by opening the valve 118. By collecting the cleaning liquid 107 by the cleaning liquid generation unit 110 in this way, the cleaning liquid 107 supplied to the apparatus can be circulated, and the temperature rise of the cleaning liquid 107 and the deterioration of the cleaning capability can be prevented.

On the other hand, a liquid recovery machine 111 is connected to the cleaning liquid recovery head 109 via a piping system. When it is determined that the apparatus has been sufficiently cleaned, the valve 118 provided between the head 109 and the liquid recovery machine 111 is opened, and the cleaning liquid is recovered from the head 109 and supplied to the liquid recovery machine 111. As a result, the cleaning liquid 107 in the apparatus is discharged.

Between the cleaning liquid supply unit head 108 and the cleaning liquid generation unit 110, a bubble generation unit 112 that generates bubbles in the cleaning liquid 107 is provided. The bubbles generated in the cleaning liquid 107 are destroyed when the saturated vapor pressure or higher is reached, and a high pressure is instantaneously generated at that time. By using the pressure at the time of the destruction of the bubbles, it is possible to effectively remove particles adhering to the inside of the apparatus.

In the bubble generation unit 112, bubbles can be generated using a cavitation jet, ultrasonic waves, or the like described below.

When bubbles are generated using a cavitation jet, a high-pressure nozzle 200 through which a high-pressure cleaning liquid flows and a low-pressure nozzle 201 through which a low-pressure cleaning liquid flows are connected to each other on the downstream side, as shown in FIG. The cavitation nozzle 202 is used. The cavitation nozzle 202 is designed so that a speed difference is generated in the vicinity of the joint between the high-speed water exiting from the high-pressure nozzle 200 and the static water (or low-speed water) exiting from the low-pressure nozzle 201. A state below the pressure is generated to form bubbles.

In the present embodiment, the cleaning liquid supplied from the cleaning liquid generation unit 110 is supplied to the high-pressure nozzle 200 and the low-pressure nozzle 201, respectively, thereby generating bubbles in the cleaning liquid in the vicinity of the coupling portion of the nozzles 200 and 201. The cleaning liquid in which bubbles are generated is supplied to the cleaning liquid supply head 108 and further to the apparatus components inside the fence 106.

Here, the pressure applied to the liquid flowing through each of the high pressure nozzle 200 and the low pressure nozzle 201 of the cavitation nozzle 202 can be adjusted. For example, the pressure can be adjusted by making the diameters of the high-pressure nozzle 200 and the low-pressure nozzle 201 variable. By manipulating the nozzle structure of the cavitation nozzle 202 and adjusting the pressure applied to the liquid flowing through both nozzles, the amount and size (average particle diameter) of the generated bubbles can be adjusted.

In the bubble generation unit 112, bubbles can be generated using the Venturi tube 300 shown in FIG. The Venturi tube 300 has a structure in which a nozzle 301 having a large diameter and a nozzle 302 having a small diameter are connected in series, and a constricted portion is provided between the nozzle 301 having a large diameter and the nozzle 302 having a small diameter. When a liquid flows from the nozzle 301 having a large diameter to the nozzle 302 having a small diameter, the flow rate is changed from a low speed to a high speed, thereby applying pressure to the fluid and generating bubbles.

In the present embodiment, bubbles are generated by flowing the cleaning liquid supplied from the cleaning liquid generating unit 110 from the nozzle 301 having a large diameter of the venturi tube 300 to the nozzle 302 having a small diameter. In addition, both nozzles have variable diameters, and the flow rate of the cleaning liquid flowing through the nozzles is changed by adjusting the diameter, and the pressure applied to the cleaning liquid is adjusted to change the amount and size of the generated bubbles. Can do.

In the bubble generation unit 112, bubbles can also be generated by an ultrasonic generator. When bubbles are generated using an ultrasonic generator, ultrasonic waves are generated in the cleaning liquid supplied from the cleaning liquid generation unit 110 to generate bubbles. Here, by appropriately adjusting the frequency of the generated ultrasonic wave, it is possible to adjust the pressure applied to the cleaning liquid and adjust the size and amount of bubbles.

As shown in FIG. 1, the bubble generation unit 112 is provided with a controller 113 for controlling the size or quantity of bubbles to be generated. The controller 113 controls the size of bubbles generated in the cleaning liquid in order to improve the particle removal effect of the cleaning liquid. Furthermore, although details will be described later, the size of bubbles generated in the cleaning liquid based on the information on the size of particles adhering to the apparatus and the information on the size (diameter) of bubbles already mixed in the cleaning liquid To control. For example, the pressure of the cavitation nozzle, the frequency of the ultrasonic device, and the like are controlled in the bubble generation unit 112 so that the size of the bubbles generated in the cleaning liquid becomes a desired size.

The controller 113 controls a storage unit (memory) that stores particle information and bubble size information that are input or transmitted, an operation of reading particle information and bubble information from the storage device, and an operation of writing to the storage device. Includes a CPU for controlling bubbles generated in the bubble generation unit 112 based on the information.

In the present embodiment, the bubble generation unit 112 and the controller 113 are both provided as components of the exposure apparatus. However, such an apparatus configuration is not necessarily required, and the bubble generation unit 112 and the controller 113 are provided outside the apparatus. It may be done. However, the bubbles generated in the cleaning liquid by the bubble generation unit 112 may disappear after a certain period of time. Therefore, it is preferable that the bubble generation unit 112 is provided at a position closer to the cleaning liquid supply head 108 inside the apparatus.

As described above, the cleaning mechanism of the immersion exposure apparatus according to the present embodiment includes the cleaning liquid supply / recovery units 108 and 109, the bubble generation unit 112, the controller 113, and the cleaning liquid generation unit 110.

Further, in the vicinity of the projection optical system 104 and the wafer stage 105 of the immersion exposure apparatus according to the present embodiment, particles that acquire information on particles to be removed attached to the apparatus 100 such as the wafer stage 105 and the projection optical system 104. A monitor 114 is provided. The particles adhering to the apparatus 100 include, for example, contaminants taken into the immersion liquid from the apparatus and the substrate during the immersion exposure, the projection optical system 104, the immersion liquid supply / recovery heads 108 and 109, and the wafer stage. For example, it may remain attached to the inside of the apparatus in contact with the immersion liquid 105 or the like, or the immersion liquid sandwiched between the back surface of the substrate and the wafer stage 105 may become a stain. Hereinafter, a method of acquiring particle information using this monitor will be described.

The particle monitor 114 includes a detector 114a and a laser irradiation unit 114b, and irradiates a laser 115 at a predetermined angle from a laser irradiation unit 114b to an apparatus component that is a cleaning region, for example, a predetermined region of the wafer stage 105. The irradiation laser 115 applied to the apparatus is reflected on the wafer stage 105, but is scattered on the surface of the irradiation area when minute projections such as particles are present on the surface of the irradiation area. The laser beam 116 thus scattered is detected by the dark field light receiving unit of the detector 114a. Furthermore, photoelectric conversion of the scattered light 116 is performed in the detector 114a to convert it into a voltage signal, and the intensity of the scattered light 116 is analyzed to obtain information on particles attached to the surface.

The timing of laser irradiation is preferably performed before and after the apparatus cleaning process. When the laser is irradiated to the device through the cleaning liquid, scattered light may be generated due to substances other than particles such as bubbles in the cleaning liquid. When such scattered light is detected by a detector, accurate particle information is obtained. Because you can't.

Here, as the particle information, it is possible to obtain information on the size, quantity, distribution, etc. of the particles. For example, the particle size and distribution are acquired as map information for each partitioned area in the laser irradiation area, and the average diameter of particles attached to the entire laser irradiation area is calculated based on the map information of the irradiation area. Can be sought. In addition, the amount (quantity) of particles attached can also be confirmed.

The particle information acquired by the particle monitor 114 is transmitted as a signal from the particle monitor 114 to the receiving unit of the controller 113 and stored in the storage unit of the controller 113. Further, even if the signal from the particle monitor 114 is not directly transmitted to the controller 113, it may be transmitted indirectly to the receiving unit of the controller 113 via an internal or external information processing apparatus. At this time, the particle information includes not only information acquired by the particle monitor 114 but also information variously processed by the user using the information processing apparatus.

Further, the user who has obtained the particle information can directly input the particle information to the particle information input unit provided in the controller 113 and store it in the internal memory of the controller 113.

The controller 113 controls the size of the bubbles generated by the bubble generation unit 112 based on the stored particle information, for example, the average diameter of the particles. The particle removal effect of the cleaning liquid greatly depends on the size of bubbles contained in the cleaning liquid. In particular, by containing a large amount of bubbles smaller than the particle size in the cleaning liquid, the particle removal effect of the cleaning liquid can be remarkably improved. In the present embodiment, the pressure applied to the cavitation nozzle 202 or the like of the bubble generation unit 112 is adjusted so that the diameter of the bubbles generated in the bubble generation unit 112 is smaller than the average diameter of the particles. By generating bubbles having a size smaller than the particle size in the cleaning liquid, the particle removal effect of the cleaning liquid can be improved. Further, since the minute bubbles are hard to disappear in the cleaning liquid and can exist for a long time, the cleaning liquid removal effect can be enhanced by containing such minute bubbles in the cleaning liquid. Specifically, the cleaning liquid removal effect can be enhanced by setting the average diameter of the bubbles to about 0.1 μm or less.

In the vicinity of the cleaning liquid supply head 108, a bubble monitor 117 for obtaining information such as the size or quantity of bubbles contained in the cleaning liquid is disposed. In the bubble monitor 117, similarly to the above-described particle monitor 114, laser light is irradiated from the irradiation unit to the cleaning liquid, and light scattered by the bubbles in the cleaning liquid is received by the detection unit, so that the bubble size (diameter) information is obtained. get. By providing the bubble monitor 117 in this way, the information on the bubbles contained in the cleaning liquid used for cleaning can be acquired, so that the effect of removing the cleaning liquid can be confirmed at any time. That is, it is possible to determine whether or not the cleaning performance of the cleaning liquid during cleaning is sufficient by checking the size or amount of bubbles that affect the cleaning liquid removal effect.

The bubble information is transmitted to and stored in the controller 113 in the same manner as the particle information. The bubble monitor 117 may be connected to the bubble generation unit 112, the cleaning liquid supply / recovery head 108/109, or the like as long as it is disposed at a position where the bubbles in the cleaning liquid can be monitored. In addition, by monitoring the cleaning liquid bubbles supplied between the wafer stage 105 and the projection optical system 104, for example, between the wafer stage 105 and the projection optical system 104, the particles are actually cleaned. It is possible to accurately acquire information on bubbles in the cleaning liquid that exerts the above.

By acquiring the bubble information in this way, the controller 113 of the bubble generation unit 112 collates the bubble information actually contained in the cleaning liquid with the particle information acquired from the particle monitor 114 to generate bubbles. Bubbles generated in the unit 112 can be controlled. For example, if it is determined whether the average diameter of the bubbles in the cleaning liquid is sufficiently small relative to the average diameter of the particles, and it is determined that the average diameter of the bubbles in the cleaning liquid is not sufficiently small, Bubbles having a smaller average diameter than the average diameter of the particles are generated in the cleaning liquid. In this way, the size of the bubbles in the cleaning liquid can be confirmed at any time, and if necessary, the bubble size can be adjusted at any time, and the particle removal efficiency of the cleaning liquid can be increased.

Next, a cleaning method for the immersion exposure apparatus according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the cleaning method.

First, after transferring a desired circuit pattern to the resist film on the semiconductor substrate using the above-described immersion exposure apparatus, the apparatus is used by the immersion liquid recovery head while stopping the supply of the immersion liquid from the immersion liquid supply head. The immersion liquid retained inside is recovered. Subsequently, the semiconductor substrate is transported from the wafer stage, and the immersion exposure process is terminated (S1).

Although it is time to end the immersion exposure process, for example, the immersion exposure process is ended when the immersion exposure is performed for a certain period of time. In addition, a measurement mechanism that measures the intensity of light that passes through the projection optical system (preferably the exposure wavelength) is provided in the immersion exposure apparatus, and ends when the light intensity measured by the measurement mechanism after immersion exposure falls below a set value You may make it do. In addition to the measurement mechanism, a calculation mechanism for calculating the light intensity decrease amount from the light intensity information measured by the measurement mechanism and a calculation mechanism for calculating the cleaning time from the light intensity decrease amount are further provided and calculated. Cleaning may be performed according to the cleaning time.

  Next, information on particles adhering to the apparatus configuration unit is acquired by a particle monitor (S2). Here, the particle information is acquired by irradiating the part in contact with the immersion liquid with laser and measuring the scattered light. The particle information includes the size, quantity, and distribution of particles attached to the apparatus in the laser irradiation area.

  Subsequently, the cleaning liquid is supplied from the cleaning liquid generating device to the bubble generating unit provided inside the apparatus, and the cleaning liquid is further supplied onto the cleaning liquid supplying unit and the wafer stage. When supplying the cleaning liquid, bubbles are generated in the cleaning liquid by the bubble generation unit (S3).

At this time, the bubble generation unit receives the particle information from the particle monitor by an internal controller, and generates bubbles by controlling the size, quantity, and the like based on the particle information. For example, based on the particle size information, the generated bubble size is controlled to be smaller than the particle size. When an ultrasonic generator is used as the bubble generation unit, it is possible to generate ultrasonic waves in the cleaning liquid and generate bubbles in the cleaning liquid. Here, by increasing the frequency applied to the cleaning liquid, the size of bubbles generated in the cleaning liquid can be more finely controlled.

At the time of cleaning, the cleaning liquid is supplied into the fence from the cleaning liquid supply head while moving the stage in the same manner as at the time of exposure. In this way, by performing cleaning while moving the stage in the same manner as in actual immersion exposure, it is possible to clean the part that is in contact with the immersion liquid. Further, it is possible to clean the apparatus while circulating the cleaning liquid by operating the cleaning liquid supply head and the cleaning liquid recovery head together.

After cleaning for a certain time, the cleaning liquid is once recovered by a cleaning liquid recovery head and the cleaning is stopped (S4).

By again irradiating the wafer stage or the like with laser and measuring the scattered light, the information on the adhered particles is confirmed, and the cleaning degree of the apparatus is judged (S5).

If it can be determined that the particles adhering to the apparatus have been sufficiently removed and the cleaning degree of the apparatus has become sufficiently high, the cleaning is completed by collecting the cleaning liquid with a cleaning liquid recovery machine (S6).

On the other hand, when it is determined that the particles are not sufficiently removed and the cleaning degree of the apparatus is insufficient, the bubbles generated in the cleaning liquid are controlled again, and the supply of the cleaning liquid is started again. The re-washing is repeated, and the washing is finished when a desired degree of washing can be obtained.

In the cleaning process, particles having a larger size than the size (average diameter) of bubbles contained in the cleaning liquid are removed, while particles having a relatively smaller size tend to remain without being removed. Therefore, at the time of re-cleaning, by the control by the controller, bubbles that are smaller in size (average diameter) than bubbles generated in the previous cleaning step are generated in the cleaning liquid, so that the minute remaining in the apparatus It is possible to remove particles efficiently and quickly.

According to the above-described cleaning method according to the present embodiment, bubbles appropriately controlled based on information on particles attached to the apparatus can be supplied to the cleaning liquid. For this reason, particles can be effectively removed in a short time in comparison with the conventional exposure apparatus cleaning method that generates bubbles in the cleaning liquid based on certain conditions regardless of the particle size, etc. Is possible.

In addition to the above-described cleaning method according to the present embodiment, it is also possible to control the bubbles generated in the cleaning liquid based on the information on the bubbles already included in the cleaning liquid.

That is, as shown in the flowchart of FIG. 5, after the exposure by the immersion exposure apparatus is completed (S1), bubbles generated based on the particle information are generated in the cleaning liquid and the cleaning liquid is supplied to the apparatus (S2). ), Information such as the size or quantity of bubbles contained in the cleaning liquid is acquired at a predetermined timing, and it is determined whether or not the bubbles contained in the cleaning liquid satisfy a desired condition (S7). . At this time, information such as the size or quantity of bubbles in the cleaning liquid is obtained by irradiating the cleaning liquid with a laser by a bubble monitor and measuring the scattered light.

If the bubbles contained in the cleaning liquid satisfy the desired conditions, for example, whether or not the bubbles in the cleaning liquid are smaller in size (average diameter) than the particles, the cleaning is continued as it is. On the other hand, when the condition is not satisfied, new bubbles are generated in the cleaning liquid again under the control of the controller in the bubble generation unit.

At this time, when a new bubble is generated in the cleaning liquid, the size information of the bubble is transmitted to the controller of the bubble generation unit in advance. In the bubble generation unit, bubbles whose dimensions and the like are newly controlled by the controller are generated in the cleaning liquid based on the particle information, the bubble information, and the information on the control conditions by the controller when the bubbles are generated. For example, in the controller, the relationship between the bubble information and the control conditions (for example, the magnitude of the applied pressure) by the controller at the time of the bubble generation is extracted, and bubbles newly generated in the cleaning liquid based on the relationship are extracted. Control. Specifically, control is performed so that the bubbles are smaller than the particles.

On the other hand, when it is determined that the bubbles contained in the cleaning liquid satisfy the desired condition, the cleaning is continued. Subsequent steps are the same steps as the cleaning method shown in the flowchart of FIG. That is, after cleaning for a certain time, the cleaning liquid is collected and the cleaning is stopped (S4). The particle information of the apparatus is confirmed, and the degree of cleaning of the apparatus is determined (S5). Cleaning is continued until it can be determined that the particles adhering to the apparatus are sufficiently removed and the cleaning degree of the apparatus is sufficiently high (S6).

As described above, by acquiring information on bubbles contained in the cleaning liquid that is actually supplied as needed, the size or quantity of bubbles in the cleaning liquid can be appropriately corrected without stopping the cleaning, and therefore, shorter Particles can be removed effectively over time.

The figure which shows the structure of the immersion exposure apparatus which concerns on the Example of this invention. The figure which shows the structure of the bubble production | generation part of the immersion exposure apparatus which concerns on the Example of this invention. The figure which shows the structure of the other bubble production | generation part of the immersion exposure apparatus which concerns on the Example of this invention. 6 is a flowchart showing a cleaning method of the immersion exposure apparatus according to the embodiment of the present invention. 6 is a flowchart showing another cleaning method of the immersion exposure apparatus according to the embodiment of the present invention.

Explanation of symbols

100: immersion exposure apparatus
101: Light source
102: Illumination optical system
103: Reticle stage
104: Projection optical system
105: Wafer stage
106: Fence
107: Cleaning solution
108: Cleaning liquid supply head (cleaning liquid supply unit)
109: Cleaning liquid recovery head (cleaning liquid recovery part)
110: Cleaning liquid generation part
111: Liquid recovery machine
112: Bubble generation unit
113: Controller
114: Particle monitor
114a: Detector
114b: Laser irradiation unit
115: Irradiation laser
116: scattered light
117: Bubble monitor 118: Valve 200: High pressure nozzle
201: Low pressure nozzle
202: Cavitation nozzle 300: Venturi tube
301: Nozzle (large) nozzle
302: Diameter (small) nozzle

Claims (5)

An immersion exposure apparatus that fills a liquid between a projection optical system and an exposure target film and irradiates the exposure target film with exposure light through the liquid,
A bubble generating unit that generates bubbles in the cleaning liquid supplied to the apparatus;
A controller for controlling bubbles generated in the bubble generation unit;
A particle monitor for acquiring information on particles attached to the device;
An immersion exposure apparatus comprising: The liquid immersion apparatus according to claim 1, further comprising a bubble monitor that acquires information on bubbles contained in the cleaning liquid. 3. The immersion exposure apparatus according to claim 1, wherein the controller has a storage unit that stores information on the particles. A method of cleaning an immersion exposure apparatus that fills a liquid between a projection optical system and a film to be exposed and irradiates exposure light onto the film to be exposed through the liquid,
Obtaining information on particles adhering to the device;
Generating bubbles controlled in the cleaning liquid based on the particle information;
Supplying a cleaning liquid containing bubbles to the inside of the apparatus;
A method for cleaning an immersion exposure apparatus, comprising: Acquiring information on bubbles contained in the cleaning liquid, controlling bubbles generated in the cleaning liquid based on information on bubbles contained in the cleaning liquid, and
The cleaning method for an immersion exposure apparatus according to claim 4, further comprising:

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