JP2006173247A - Contaminant remover, aligner and method of manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contaminant remover for removing contaminant adhering to the surface of an optical element on the side of a projection optical system closest to a substrate efficiently, and to provide an aligner capable of enhancing exposure precision, and a method of manufacturing device for producing high integration devices efficiently with high yield. <P>SOLUTION: The contaminant remover 18 comprises a nozzle 25 having a suction opening 31, a duct 26 for discharging contaminants sucked from the nozzle 25 to the outside, and a fan 27 provided in that duct 26. Each suction opening 31 of the nozzle 25 is arranged to surround the outer circumference of an optical element 22 substantially symmetrically to the center thereof and arranged just beside the lower surface 22a of the optical element 22. The suction openings 31 thus arranged are located on the downstream side of air flow in a wafer chamber 40 for the optical element 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a contaminant removing apparatus, an exposure apparatus, and a device manufacturing method, and more specifically, a contaminant removing apparatus and an exposure that focus on removing a contaminant adhering to the optical element surface closest to the substrate of a projection optical system. The present invention relates to an apparatus and a device manufacturing method.

  In an exposure apparatus, a reticle such as a reticle or a photomask on which a predetermined pattern is formed is illuminated with predetermined exposure light, and an image of the predetermined pattern is coated with a photosensitive resin such as a photoresist via a projection optical system. Exposure is performed on a substrate such as a wafer or a glass plate.

  In an exposure process using this type of exposure apparatus, a photosensitive resin (for example, a novolak resin) is generally used as a resist layer applied on a wafer. For this reason, at the time of projection exposure, volatile substances generated from the photosensitive resin may adhere to the surface of the optical element located closest to the wafer in the projection optical system and contaminate the surface of the optical element. In recent years, due to the demand for higher density devices, exposure apparatuses are also required to have high resolution. If the surface of the optical element is contaminated in this way, the optical characteristics of the projection optical system (especially the projection optical system) The transmittance of the passing exposure light and the like may change, resulting in exposure failure. Therefore, the frequency of removing the optical element from the lens barrel and cleaning or replacing the optical element has increased.

However, on the other hand, improvement in device productivity is also demanded, and removing the optical element from the lens barrel in this way, washing, and replacing it temporarily stops the production process and reduces productivity. Therefore, in order to reduce the frequency of removing the optical element from the lens barrel, a contaminant removal apparatus as described in Patent Document 1, for example, has been proposed. FIG. 7 is a plan view showing the contaminant removal apparatus described in Patent Document 1. As shown in FIG. In this contaminant removal apparatus 201, a plurality of suction nozzles 203 (vacuum manifold 202) are installed between a wafer 204 and an optical element (not shown), and contaminants are removed from the surface of the optical element by the suction nozzle 203. An air flow in a removing direction is generated so that the contaminant does not adhere to the optical element, and the adhered contaminant is sucked and removed.
US Pat. No. 5,973,764 (Claim 1, FIG. 1)

  By the way, the exposure apparatus includes an environment control device. This environmental control apparatus has a chamber for storing an exposure apparatus main body, and in this chamber, a contaminant is removed and it is usually cleaner than in a clean room where an exposure apparatus is installed. Filled with air. For this reason, the chamber is provided with a blower and is controlled so as to keep the air flow in the chamber constant. This is to suppress a measurement error of an interferometer (wafer stage interferometer, reticle stage interferometer, etc.) due to air fluctuations and a deterioration in exposure accuracy due to a temperature change caused by heat generated from various driving means.

  As in the pollutant removing device 201 described in Patent Document 1, even if air is sucked from all the surrounding directions without considering this air flow (see FIG. 7), the contaminants in the vicinity of the optical element are removed. Can do. However, when the vacuum manifold 202 is configured so as to surround the optical element as in the conventional contaminant removal apparatus 201, the apparatus itself requires a large space. Here, in recent exposure apparatuses, the wafer stage that operates violently due to high throughput and device enlargement, and various auxiliary machines, measuring instruments, wiring, and piping provided around the optical stage located on the wafer side. The space around the element is extremely scarce. Therefore, there has been a problem that it is difficult to secure a large space in the vicinity of the optical element as in the prior art.

On the other hand, if the contaminants are not removed reliably, there is a problem that the frequency of cleaning and replacement of the optical element increases and the productivity of the device decreases.
The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a contaminant removal apparatus that can efficiently remove contaminants adhering to the surface of the optical element closest to the substrate of the projection optical system. Another object of the present invention is to provide an exposure apparatus capable of improving exposure accuracy. A further object of the present invention is to provide a device manufacturing method capable of efficiently producing a highly integrated device with a high yield.

  In order to achieve the above object, an invention according to claim 1 has a chamber for housing an exposure apparatus main body, supplies gas into the chamber to control the environment in the chamber, In an exposure apparatus equipped with an environment control device that controls the flow of the supplied gas, a contaminant that adheres to the surface of the optical element closest to the substrate of the projection optical system of the exposure apparatus is disposed in the vicinity of the optical element. A pollutant removing device that sucks and removes at least one suction port, wherein the at least one suction port is provided downstream of the optical element in the gas flow direction.

  Therefore, according to the first aspect of the present invention, since at least one suction port is provided on the downstream side of the optical element in the gas flow direction in the chamber, the downstream of the optical element along the air flow. Contaminants that have flowed to the side can be efficiently sucked before adhering to the optical element. Since the contamination of the optical element is suppressed by efficiently removing the contaminant, the frequency of cleaning and replacement of the optical element can be reduced, and the productivity of the device can be improved.

  According to a second aspect of the present invention, in the pollutant removal device according to the first aspect, a plurality of the suction ports are arranged at different positions on the downstream side with respect to the optical element, and the contaminants are extracted from the suction ports. It is characterized by suctioning with gas.

  Therefore, according to the second aspect of the present invention, the contaminants are sucked from the suction ports arranged at a plurality of different positions, so that it is possible to suitably suppress the contaminants from adhering to the optical element. .

  A third aspect of the present invention is the pollutant removing device according to the first or second aspect, wherein the suction port discharges the gas containing the contaminant sucked from the suction port to the outside of the chamber. The duct is provided with a suction mechanism for increasing the suction force by the suction port.

Therefore, according to the third aspect of the present invention, the suction force provided by the suction port can be increased by the suction mechanism provided in the duct connected to the suction port.
According to a fourth aspect of the present invention, in the contaminant removal apparatus according to the third aspect, the suction mechanism includes a fan.

Therefore, according to the invention described in claim 4, since the suction mechanism includes the fan, the invention described in claim 3 can be more suitably implemented.
According to a fifth aspect of the present invention, in the contaminant removal apparatus according to the fourth aspect, the fan is provided in the chamber.

  Therefore, according to the fifth aspect of the present invention, since the fan is provided in the chamber, normally, the suction force by the suction port is reduced without taking in the gas outside the chamber, which is less clean than in the chamber. Can be increased.

  The invention according to claim 6 is the pollutant removal apparatus according to any one of claims 1 to 5, wherein the gas in the chamber sucked together with the contaminant is sucked when the contaminant is sucked. A gas circulation device is provided for removing the contaminant contained in the gas and returning it to the chamber again.

  Therefore, according to the sixth aspect of the present invention, the gas in the chamber sucked together with the pollutant can be circulated again into the chamber after removing the pollutant contained in the gas by the gas circulation device. it can.

A seventh aspect of the present invention is the pollutant removing device according to the sixth aspect, wherein the gas circulation device includes a forced circulator that sucks and pumps the gas.
Therefore, in the invention regulated in claim 7, the gas can be circulated into the chamber by sucking and pumping the gas in the chamber by the forced circulator.

An exposure apparatus according to an eighth aspect includes the contaminant removal apparatus according to any one of the first to seventh aspects.
Therefore, according to the invention described in claim 8, since the contamination of the optical element is suitably suppressed by the contaminant removing device, it is possible to provide an exposure device with stable optical characteristics.

  According to a ninth aspect of the present invention, there is provided a device manufacturing method including a lithography process, wherein exposure is performed using the exposure apparatus according to the eighth aspect in the lithography process.

  Therefore, according to the ninth aspect of the present invention, a high-quality device can be manufactured with a high yield by using an exposure apparatus with stable optical characteristics.

  According to the present invention, contaminants adhering to the surface of the optical element closest to the substrate of the projection optical system can be efficiently removed. In addition, an exposure apparatus with high exposure accuracy can be provided. Furthermore, it is possible to provide a device manufacturing method capable of efficiently producing a highly integrated device with a high yield.

  Hereinafter, an exposure apparatus and a contaminant removal apparatus according to the present invention are used as an exposure apparatus for manufacturing a semiconductor element and a contaminant removal apparatus that removes a contaminant adhering to the optical element surface on the most substrate side of a projection optical system included in the exposure apparatus. 1 to 6 will be described with reference to FIGS.

  FIG. 1 is a schematic block diagram of an exposure apparatus 11 according to the present embodiment. As shown in FIG. 1, an exposure apparatus 11 of this embodiment includes a light source 12, an illumination optical system 13, a reticle stage RST that holds a reticle R as a mask, a projection optical system PL, and a wafer W as a substrate. And a wafer stage WST for holding the wafer. In the exposure process, a photosensitive resin (for example, novolak resin) is applied as a resist layer on the wafer W.

  The exposure apparatus main body 14 is constituted by the illumination optical system 13, the reticle stage RST, the projection optical system PL, and the wafer stage WST, and these members are housed in a main body chamber 101 (see FIG. 2) described later. In the main body chamber 101, some of the optical members constituting the illumination optical system 13 are accommodated.

In this embodiment, the light source 12 oscillates an ArF excimer laser having a wavelength of 193 nm. In addition, a KrF excimer laser with a wavelength of 248 nm, an F ₂ laser with a wavelength of 157 nm, or the like can be used.

  The illumination optical system 13 includes an optical integrator (not shown) such as a fly-eye lens and a rod lens, various optical elements such as a relay lens and a condenser lens, and a plurality of optical members such as an aperture stop. Then, the exposure light EL emitted from the light source 12 is adjusted so as to uniformly illuminate the pattern on the reticle R by passing through the illumination optical system 13.

  In reticle stage RST, on the exit side of illumination optical system 13, that is, on the object surface side (incident side of exposure light EL) of projection optical system PL described later, the mounting surface of reticle R is the optical axis of projection optical system PL. They are arranged so as to be substantially orthogonal to the AX direction.

  The projection optical system PL is composed of a plurality of optical elements 21 and 22 such as lenses. In the projection optical system PL, optical elements 21 and 22 are accommodated in a lens barrel 23 formed by stacking a plurality of lens barrel modules (not shown) so that the optical axes AX coincide with each other. Each of the plurality of lens barrel modules holds one or more optical elements 21 and 22. Among the optical elements constituting the projection optical system PL, the optical element 22 closest to the wafer W (image plane side) is a substantially parallel plate lens, and the lower surface 22a thereof is the projection optical system PL (lens barrel 23). ) And exposed from the lower surface.

  Wafer stage WST is arranged on the image plane side of projection optical system PL (exit side of exposure light EL) so that the mounting surface of wafer W intersects the optical axis direction of projection optical system PL. Then, the image of the pattern on the reticle R illuminated by the exposure light EL is projected and transferred onto the wafer W on the wafer stage WST in a state reduced to a predetermined reduction magnification through the projection optical system PL. ing.

  Here, the energy of the ArF excimer laser light used in the exposure apparatus 11 is easily absorbed by substances such as oxygen molecules and carbon dioxide molecules contained in the air. Therefore, in the exposure apparatus 11, the illumination optical path (the optical path from the light source 12 to the reticle R) and the projection optical path (the optical path from the reticle R to the wafer W) are blocked from the external atmosphere, and these optical paths are against ArF excimer laser light. Filled with gas with low absorption characteristics. This gas is a single gas selected from nitrogen, helium, neon, argon, krypton, xenon, radon, or the like, or a mixed gas thereof.

Next, the environment control apparatus of this embodiment will be described.
FIG. 2 is a schematic configuration diagram illustrating the environment control apparatus. As shown in FIG. 2, the environment control apparatus 100 houses an exposure apparatus 11 (not shown in FIG. 2) disposed in a clean room as an external environment, and includes a main body chamber 101 that houses the exposure apparatus 11. And an air conditioning unit 102 for supplying air with controlled temperature, humidity and the like into the main body chamber 101.

  The main body chamber 101 is disposed on the floor surface in the clean room, and the air conditioning unit 102 is disposed in the utility room disposed under the floor of the clean room or adjacent to the clean room, which is in a different environment from the clean room in which the main body chamber 101 is disposed. Has been. The main body chamber 101 and the air conditioning unit 102 are connected via a duct 103.

  Here, in the clean room, the indoor environment (temperature, impurity concentration, etc.) is managed with high accuracy, whereas the utility room does not require strict environmental management as in the clean room. In the present embodiment, by arranging the air conditioning unit 102 in the utility room, the space related to the exposure processing in the clean room is reduced and the management cost is reduced.

  The air conditioning unit 102 takes in external air, adjusts it to a predetermined temperature, removes impurities in the air, and supplies the air to the main body chamber 101. The housing 50 and the housing 50 is provided with a fan motor 51 or the like as a take-in mechanism disposed in the inside.

  The casing 50 of the air conditioning unit 102 is provided with an intake port 50a for taking in external air and an exhaust port 50b for discharging the taken-in air. 103. Further, a temperature regulator 52 and a humidity regulator 53 are disposed between the intake port 50a and the fan motor 51, and a first impurity removal mechanism 54 is disposed between the fan motor 51 and the discharge port 50b. Is arranged.

  The temperature adjuster 52 adjusts the air taken into the housing 50 through the intake port 50a to a predetermined temperature. The cooling cooler 60 is upstream and the heating heater 61 is downstream. It has become the composition which arranged. The temperature adjuster 52 includes a temperature sensor (not shown) that detects the temperature of the air. Based on the detection result of the temperature sensor, the cooler 60 and the heater 61 are controlled by a control device (not shown). The

  The humidity adjuster 53 is for adjusting the humidity of the air temperature-controlled by the temperature adjuster 52, and includes a humidifier 65 and a humidity sensor (not shown). In the present embodiment, a type that detects the relative humidity of air is used as the humidity sensor, and specifically, an impedance / capacitance change type, an electromagnetic wave absorption type, a heat conduction application type, a crystal vibration type, and the like are used. The humidifier 65 is controlled by a control device (not shown) based on the detection result of a humidity sensor (not shown) that detects the humidity of the air.

  The first impurity removal mechanism 54 is for removing impurities in the air taken into the housing 50 through the intake port 50a. In the present embodiment, the first impurity removal mechanism 54 is a chemical that removes gaseous pollutants that adhere to various optical elements such as oxygen and organic compounds in the air and cause a decrease in optical performance of those optical elements. A filter 66 and an ULPA filter 67 (Ultra Low Penetration Air-filter) that removes particulates in the air are provided. Each filter is not limited to a single filter, and a plurality of filters may be used as necessary. Further, instead of the ULPA filter, a HEPA filter (High Efficient Particulate Air-filter) may be used.

  Here, as the chemical filter 66, for example, a gaseous alkaline substance removal, a gaseous acidic substance removal, a gaseous organic substance removal, or the like is used. Specifically, for example, activated carbon type (for removing gaseous organic substances), additive activated carbon type (for removing gaseous alkaline substances and gaseous acidic substances), ion exchange fiber type (for removing gaseous alkaline substances, For removal of gaseous acidic substances), ion exchange resin type (for removal of gaseous alkaline substances, for removal of gaseous acidic substances), ceramics type (for removal of gaseous organic substances), and ceramics type for additives (for removal of gaseous alkaline substances) For removing gaseous acidic substances). These may be used singly or in any combination of two or more. Examples of combinations include, for example, a combination of activated carbon type, additive activated carbon type and ion exchange resin type, or activated carbon type and ion exchange fiber type (for removing gaseous acidic substances) and ion exchange fiber type (gaseous alkaline). And a combination with (for substance removal).

Next, the main body chamber 101 will be described.
Inside the main body chamber 101, an exposure chamber 110 in which the exposure apparatus 11 is accommodated, a reticle loader chamber 111 as a space in which a plurality of reticles R are accommodated, and a wafer loader as a space in which a plurality of wafers W are accommodated. The chamber 112 is partitioned.

  The reticle loader chamber 111 accommodates a reticle library 71 that stores a plurality of reticles R, and a reticle loader 72 that is disposed closer to the exposure chamber 110 than the reticle library 71 and is composed of a horizontal articulated robot. ing. The reticle loader 72 carries an arbitrary one reticle R out of a plurality of reticles R stored in the reticle library 71 onto the reticle stage RST, and the reticle R on the reticle stage RST is transferred to the reticle library 71. Or carry it out.

  Inside wafer loader chamber 112, wafer carrier 76 for storing a plurality of wafers W, horizontal articulated robot 77 for loading / unloading wafers W into / from wafer carrier 76, horizontal articulated robot 77 and wafer stage WST, And a wafer transfer device 78 for transferring the wafer W between them.

  Inside the main body chamber 101, a guide passage 80 is provided for guiding the gas introduced from the air conditioning unit 102 through the duct 103 to the exposure chamber 110, reticle loader chamber 111, and wafer loader chamber 112. . The air adjusted by the air conditioning unit 102 described above is sent to each of the exposure chamber 110, reticle loader chamber 111, and wafer loader chamber 112 via the guide passage 80.

  An opening 80a connected to the duct 103 is provided at the upstream end of the guide passage 80, and a chemical filter 81 as a second impurity removal mechanism is disposed in the opening 80a. As the chemical filter 81, the same one as the chemical filter 66 described above can be used.

  In the guide passage 80, filter boxes 82, 83, and 84 for removing particulates in the air are connected to connecting portions of the exposure chamber 110, the reticle loader chamber 111, and the wafer loader chamber 112. It is arranged. More specifically, the exposure chamber 110, the reticle loader chamber 111, and the wafer loader chamber 112 are provided with blowing ports 80b, 80c, and 80d for introducing the air from the air conditioning unit 102 into the inside. The filter boxes 82, 83, 84 are disposed at 80b, 80c, 80d. The filter boxes 82, 83, and 84 are composed of a ULPA filter and a filter plenum.

  The main body chamber 101 is provided with exhaust ports 80e, 80f, 80g, and 80h for exhausting internal air to the outside. Specifically, in the exposure chamber 110, exhaust ports 80 e and 80 f are disposed at positions opposite to the air blowing port 80 b with the exposure apparatus 11 interposed therebetween, and in the reticle loader chamber 111, air is blown with the reticle library 71 and the reticle loader 72 interposed therebetween. An exhaust port 80g is disposed at a position facing the port 80c. In the wafer loader chamber 112, an exhaust port 80h is disposed at a position facing the air blowing port 80d with the wafer carrier 76, the horizontal articulated robot 77, and the wafer transfer device 78 interposed therebetween.

The air conditioning operation of the main body chamber 101 configured as described above will be described.
First, when the fan motor 51 of the air conditioning unit 102 is activated, air is taken into the air conditioning unit 102 (housing 50) through the intake port 50a by the suction force of the fan motor 51. In the air conditioning unit 102, the air taken in from the intake port 50 a is adjusted to the target temperature by the temperature adjuster 52 and adjusted to the target humidity by the humidity adjuster 53. The air whose temperature and humidity have been adjusted passes through the chemical filter 66 in the first impurity removal mechanism 54 to contaminate various optical elements (gaseous alkaline substance, gaseous acidic substance, gaseous organic substance). Is almost completely removed by adsorption. Further, the fine particles (particles) in the air are almost completely removed by passing through the ULPA filter 67.

  Thus, air that has been subjected to predetermined adjustments such as impurity removal and temperature adjustment is sent to the main body chamber 101 via the duct 103. Specifically, the air adjusted by the air conditioning unit 102 passes through the duct 103 and then flows into the guide passage 80 in the main body chamber 101, and the exposure chamber 110, the reticle loader chamber 111, and the wafer loader chamber 112. Sent to.

  Here, a chemical filter 81 is disposed in the opening 80 a of the guide passage 80 that is an inlet of air to the main body chamber 101, and air that is an inlet of each of the exposure chamber 110, the reticle loader chamber 111, and the wafer loader chamber 112. Filter boxes (ULPA filters) 82, 83, 84 are provided at the openings 80b, 80c, 80d. Therefore, impurities (fine particles and the like) contained in the air are further removed by these filters 81 to 84. That is, the entry of impurities into the chambers 110, 111, and 112 is more reliably prevented.

  And the air (cleanness, temperature, humidity, etc.) in each room is controlled to the target state by filling each room with the air sent to each room 110, 111, 112. At this time, a part of the air is exhausted to the outside of the main body chamber 101 through the exhaust ports 80e, 80f, 80g, and 80h. That is, the air taken into the air conditioning unit 102 is discharged outside through the main body chamber 101.

  As described above, the environment control apparatus 100 performs air conditioning by flowing air in one direction from the air conditioning unit 102 toward the main body chamber 101 as a whole. Therefore, in the air supply passage between the fan motor 51 and the exhaust ports 80e, 80f, 80g, and 80h, a negative pressure region is not generated with respect to the outside air pressure, and the air (outside air) into the main body chamber 101 is not generated. ) Is prevented from entering.

Next, the local circulation system 87 arranged in the main body chamber 101 will be described.
As shown in FIGS. 1 and 2, the local circulation system 87 takes in the air introduced into the exposure chamber 110 and circulates the air locally, and adjusts the air temperature, humidity, and the like. Part 120 and a circulation passage 121 forming a flow path for circulating air. In the present embodiment, the local circulation system 87 circulates the air in a local space (wafer chamber 40) including the wafer stage WST in the internal space of the exposure chamber 110.

  The air conditioning unit 120 sequentially arranges a temperature adjustment cooler 123, a fan motor 124, and an impurity removal mechanism 125 in the direction of air flow in a case 122 disposed outside and adjacent to the main body chamber 101. Configured. Like the cooler 60 described above, the cooler 123 is for adjusting the air taken into the housing 122 to a predetermined temperature, and is controlled based on the detection result of a temperature sensor (not shown). In addition, as the fan motor 124, a fan motor having a smaller blowing capacity than the fan motor 51 for the air conditioning unit 102 described above is used. Further, the impurity removal mechanism 125 includes a chemical filter 126 and a ULPA filter 127 as in the first impurity removal mechanism 54 described above.

  The circulation passage 121 is provided with an inlet 130 for taking in the air in the exposure chamber 110, an outlet 131 for discharging the air in the wafer chamber 40, and an air outlet 132 provided on the side surface of the wafer chamber 40. It has been.

  The circulation passage 121 is provided with an ULPA filter 140 as an impurity removing means for further removing fine particles contained in the air sent from the air conditioning unit 120. The ULPA filter 140 is disposed upstream of the air blowing port 132 with air from the air conditioning unit 120.

  In the local circulation system 87, air is circulated through the circulation passage 121 by the operation of the fan motor 124 of the air conditioning unit 120. Specifically, the air taken in from the intake port 130 and the air exhausted from the exhaust port 131 are temperature-controlled by the cooler 123, and further, contaminants or fine particles contained in the air are removed from the impurity removal mechanism 125 ( Chemical filter 126 and ULPA filter 127) are removed. The air that has passed through the air conditioning unit 120 flows through the circulation passage 121, and the particulates are further removed by the ULPA filter 140. Then, the air whose temperature and cleanliness are adjusted is sent to the arrangement space of wafer stage WST (inside wafer chamber 40) through blower port 132. As a result, each arrangement space of wafer stage WST is filled with air adjusted by air conditioning unit 120.

Next, the pollutant removal apparatus 18 that is a main part of the present invention will be described.
As shown in FIG. 1, the contaminant removing device 18 is disposed below the projection optical system PL, and is generated near the optical element 22 closest to the wafer W (hereinafter simply referred to as “optical element 22”). Is a device for removing by suction. The contaminant removing device 18 includes a nozzle 25 having a suction port 31 at one end, a duct 26 for discharging the contaminant sucked from the nozzle 25 to the outside, and a fan 27 provided in the duct 26. ing.

  3 is a plan view of the nozzle 25, and FIG. 4 is an overall perspective view of the nozzle. Note that the optical element 22 is indicated by a broken line in FIG. As shown in FIGS. 3 and 4, the nozzle 25 is a flat hollow member having a substantially U shape in a plan view, and has two suction ports 31 at the tip. The vicinity of the suction port 31 is formed to be thinner than other portions, has a shape that can be easily installed in a narrow space between the optical element 22 and the wafer W, and gas in the vicinity of the suction port 31. To increase the flow velocity. When installed in the main body chamber 101, each suction port 31 of the nozzle 25 is positioned downstream of the optical element 22 in the air flow in the main body chamber 101 (in this embodiment, the wafer chamber 40). (See FIG. 1). In addition, each suction port 31 is disposed substantially symmetrically with respect to the center of the optical element 22 and almost beside the lower surface 22 a of the optical element 22 as if surrounding the outer periphery of the optical element 22. Further, the suction direction of the nozzle 25 (the right direction in FIG. 1) matches the air flow direction in the wafer chamber 40.

  A fan 27 is connected to the other end of the nozzle 25, and the suction force of contaminants by the nozzle 25 is enhanced by the fan 27. In other words, the suction action of the fan 27 allows the suction port 31 of the nozzle 25 to suck air containing contaminants from between the optical element 22 and the wafer W. As the fan 27, a known axial fan having 4 to 6 propeller blades can be used. In addition, a centrifugal fan or a mixed flow fan may be used depending on the installation mode.

  The fan 27 is connected to a pressure feeding device 34 constituted by a pump or the like via a duct 26. One end of an air circulation pipe 36 is connected to the pressure feeding device 34. The other end of the air circulation pipe 36 is connected to the upstream side of the cooler 123 in the circulation passage 121 of the local circulation system 87. Therefore, the pressure feeding device 34 pressure feeds the air sucked by the nozzle 25 to the local circulation system 87 again through the air circulation pipe 36.

The compressed air is returned to the wafer chamber 40 again after contaminants contained in the air are removed by the local circulation system 87.
(Function)
In the exposure process of the exposure apparatus 11 configured as described above, when the exposure light EL is illuminated, a volatile substance is generated from a photosensitive resin as a resist layer applied on the wafer W. If this volatile material adheres to the optical element 22 (particularly the lower surface 22a) exposed on the lower surface of the projection optical system PL, there is a possibility that the optical characteristics will change and cause exposure failure. In the present embodiment, in order to avoid such problems, contaminants such as volatile substances are periodically removed by the contaminant removing device 18. The operation will be described below.

  As described above, a constant air flow is generated in the wafer chamber 40 by the local circulation system 87, and contaminants generated from the wafer W are caused to flow in the air flow direction. Here, in this embodiment, the nozzle 25 of the pollutant removing device 18 is arranged with the suction port 31 positioned on the side in which the pollutant flows, that is, on the downstream side of the optical element 22 in the air flow direction. Yes. Therefore, when the fan 27 and the pressure feeding device 34 are driven by a control device (not shown), an air flow in the suction direction (rightward in FIG. 1) is generated in the vicinity of each suction port 31 of the nozzle 25, and the wafer W The generated pollutant is sucked from the two suction ports 31 of the nozzle 25 when it has flowed downstream along the air flow.

  As described above, the contaminant is sucked from the nozzle 25 before reaching the optical element 22 (the lower surface 22a which is an exposed surface), so that the contaminant is prevented from adhering to the optical element 22.

  The sucked air containing the contaminant is pumped from the pumping device 34 to the circulation passage 121 through the air circulation pipe 36, passes through the local circulation system 87, and is supplied again into the wafer chamber 40. At this time, the contaminant contained in the sucked air is removed by passing through the impurity removal mechanism 125, and thus purified air that does not contain the contaminant is supplied into the wafer chamber 40. The air supplied into the wafer chamber 40 flows in the wafer chamber 40 in a certain direction, and thereafter circulates in the wafer chamber 40 as described above.

Although the configuration and operation of the contaminant removal apparatus 18 have been described in detail above, the exposure apparatus 11 shown in FIG. 1 including the contaminant removal apparatus 18 is manufactured, for example, as follows.
First, a plurality of optical elements 21 and 22 constituting the projection optical system PL are held by an optical element holding device (not shown), and the projection optical system PL housed in the lens barrel 23 is incorporated in the main body of the exposure apparatus 11. Perform optical adjustment.

Next, a wafer stage WST (including a reticle stage RST in the case of a scan type exposure apparatus) made up of a large number of mechanical parts is attached to the main body of the exposure apparatus 11 to connect wiring. Then, after the gas supply pipe for supplying the gas is connected to the optical path of the exposure light, the inside of the lens barrel 23 is purged. In this case, N ₂ is filled after thoroughly removing O ₂ and moisture in the lens barrel 23. Furthermore, comprehensive adjustment (electric adjustment, operation check, etc.) is performed.

  Here, each component constituting the optical element holding device and the sealing member such as an O-ring are processed by ultrasonic cleaning or the like so that impurities such as processing oil and metal substances are dropped and do not become an outgas emission source. Assembled. The exposure apparatus 11 is preferably manufactured in a clean room in which the temperature, humidity, and atmospheric pressure are controlled and the cleanness is adjusted.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 11 in a lithography process will be described.
FIG. 5 is a flowchart showing a manufacturing example of a device (a semiconductor element such as an IC or LSI, a liquid crystal display element, an image pickup element (CCD or the like), a thin film magnetic head, a micromachine, or the like). As shown in FIG. 4, first, in step S101 (design step), function / performance design (for example, circuit design of a semiconductor device) of a device (microdevice) is performed, and pattern design for realizing the function is performed. Do. Subsequently, in step S102 (mask manufacturing step), a mask (such as a reticle Rt) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S103 (substrate manufacturing step), a substrate (or a wafer W when a silicon material is used) is manufactured using a material such as silicon or a glass plate.

  Next, in step S104 (substrate processing step), using the mask and substrate prepared in steps S101 to S103, an actual circuit or the like is formed on the substrate by lithography or the like, as will be described later. Next, in step S105 (device assembly step), device assembly is performed using the substrate processed in step S104. Step S105 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation or the like) as necessary.

  Finally, in step S106 (inspection step), inspections such as an operation confirmation test and a durability test of the device manufactured in step S105 are performed. After these steps, the device is completed and shipped.

  FIG. 6 is a diagram showing an example of a detailed flow of step S104 of FIG. 5 in the case of a semiconductor device. In FIG. 6, in step S111 (oxidation step), the surface of the wafer W is oxidized. In step S112 (CVD step), an insulating film is formed on the surface of the wafer W. In step S113 (electrode formation step), an electrode is formed on the wafer W by vapor deposition. In step S114 (ion implantation step), ions are implanted into the wafer W. Each of the above steps S111 to S114 constitutes a pretreatment process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, a photosensitive agent is applied to the wafer W in step S115 (resist formation step). Subsequently, in step S116 (exposure step), the circuit pattern of the mask (reticle Rt) is transferred onto the wafer W by the lithography system (exposure apparatus 11) described above. Next, in step S117 (developing step), the exposed wafer W is developed, and in step S118 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step S119 (resist removal step), the resist that has become unnecessary after the etching is removed.

Multiple circuit patterns are formed on the wafer W by repeatedly performing these pre-processing and post-processing steps.
If the device manufacturing method of the present embodiment described above is used, the exposure apparatus 11 is used in the exposure step (step S116), the resolution can be improved by the exposure light EL of the ArF excimer laser, and the exposure amount can be controlled. It can be performed with high accuracy. Therefore, as a result, a highly integrated device having a minimum line width of 0.1 μm can be produced with a high yield.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the suction port 31 of the nozzle 25 of the contaminant removing device 18 is provided so as to be located downstream of the optical element 22 in the air flow in the wafer chamber 40. Contaminants generated from the wafer W flow downstream along the flow of air in the wafer chamber 40, so that the amount of contaminants is larger than when the suction port 31 of the nozzle 25 is provided on the upstream side. The air contained in can be efficiently sucked.

  (2) Since the contamination of the optical element 22 is suppressed by efficiently sucking the contaminants in this way, the frequency of cleaning and replacement of the optical element 22 can be reduced, and device productivity can be improved. Can contribute.

  (3) In the above embodiment, the fan 26 is provided in the duct 26, and contaminants are sucked by the suction force of both the pressure feeding device 34 and the fan 27. Of course, it is possible to suck contaminants only by the suction action of the pressure feeding device 34, but the suction force is increased by installing the fan 27, so that the air in the vicinity of the optical element 22 is sucked more efficiently. Thus, contaminants can be removed more reliably.

  (4) In the above embodiment, the suction direction from the nozzle 25 (the right direction in FIG. 1) and the flow direction of the air in the wafer chamber 40 coincide with each other, and thus the air flow in the wafer chamber 40 is opposed. In this way, contaminants can be sucked more efficiently.

  (5) In the above embodiment, two suction ports 31 as suction ports are formed by the substantially U-shaped nozzle 25, and each of these suction ports 31 is disposed substantially symmetrically with respect to the center of the optical element 22. . For this reason, the air in the wafer chamber 40 containing the contaminant can be sucked from a plurality of different positions, and the contaminant can be suitably prevented from adhering to the optical element 22.

  (6) In addition, since each suction port 31 is provided on the downstream side of the air flow and substantially beside the optical element 22, the generated contaminants are exposed to the exposed surface (lower surface) of the optical element 22. 22a) The suction can be reliably performed in the vicinity.

  (7) Furthermore, in the said embodiment, since each several suction port 31 is comprised by making the shape which branched the nozzle 25, there exists an effect shown to said (5) with an easy apparatus structure. it can. Since it can be implemented easily and with an apparatus configuration that does not take up space, it can be suitably installed in the wafer chamber 40 in the vicinity of the narrow optical element 22.

In addition, you may change the said embodiment as follows.
In the above-described embodiment, each suction port 31 of the nozzle 25 is configured to be positioned almost directly beside the optical element 22. However, if the air flow in the wafer chamber 40 is on the downstream side of the optical element 22, optical It does not have to be next to the element 22. At least if it is provided on the downstream side, the contaminant generated from the wafer W is sucked from the suction port 31 of the nozzle 25 when it flows downstream along the air flow in the wafer chamber 40. Compared with the case where it is provided on the upstream side, contaminants can be efficiently sucked. Further, the suction port 31 can also be disposed so as to be located directly below the lower surface 22a of the optical element 22. In this case, there is no problem as long as the suction port 31 of the nozzle 25 does not block the exposure light EL from the illumination optical system 13, that is, as long as it does not block the optical path.

  In the above embodiment, the U-shaped nozzle 25 has two suction ports 31, but the shape of the nozzle 25 is not limited to this, and the suction port 31 of the nozzle 25 is It may be singular.

  In the above embodiment, the air containing the contaminant sucked from the nozzle 25 is configured to be returned to the wafer chamber 40 after removing the pollutant, but the air sucked from the nozzle 25 is not circulated as it is. It is good also as composition which exhausts. In this case, the other end of the air circulation pipe 36 may be connected to the factory exhaust pipe.

In the above embodiment, the fan 27 in the pollutant removing device 18 may not be provided. In this case, the pressure feeding device 34 also serves as the suction means of the contaminant removing device 18.
○ Also, from a reticle to a glass substrate for manufacturing reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, and electron beam exposure apparatuses The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a silicon wafer or the like. Here, in an exposure apparatus using DUV (deep ultraviolet), VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As the reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, fluoride, and the like are used. Magnesium or quartz is used. In proximity-type X-ray exposure apparatuses, electron beam exposure apparatuses, and the like, a transmissive mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.

  Further, the exposure apparatus may be an exposure apparatus that uses an immersion method in order to ensure a wide depth of focus. In this immersion method, a space between the lower surface of the projection optical system and the substrate surface is filled with a predetermined liquid (such as water or an organic solvent) to form an immersion region, and the wavelength of exposure light in the liquid is air. The resolution is improved by utilizing 1 / n (n is the refractive index of the liquid, usually about 1.2 to 1.6), and the depth of focus is expanded about n times.

  Of course, the present invention is applied not only to an exposure apparatus used for manufacturing a semiconductor element but also to an exposure apparatus used for manufacturing a display including a liquid crystal display element (LCD) to transfer a device pattern onto a glass plate. can do. The present invention can also be applied to an exposure apparatus used for manufacturing a thin film magnetic head or the like and transferring a device pattern to a ceramic wafer or the like, and an exposure apparatus used for manufacturing an image pickup device such as a CCD.

  Further, the present invention can be applied to a scanning stepper that transfers a mask pattern to a substrate while the mask and the substrate are relatively moved, and sequentially moves the substrate in steps. The present invention can also be applied to a step-and-repeat stepper in which the mask pattern is transferred to the substrate while the mask and the substrate are stationary, and the substrate is sequentially moved stepwise.

As a light source of the exposure apparatus, in addition to the ArF excimer laser (193 nm) described in the above embodiment, an F ₂ laser (157 nm), g line (436 nm), i line (365 nm), KrF excimer laser (248 nm) Kr ₂ laser (146 nm), Ar ₂ laser (126 nm), or the like may be used. In addition, a single wavelength laser beam oscillated from a DFB semiconductor laser or fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium), and a nonlinear optical crystal is obtained. It is also possible to use harmonics that have been converted into ultraviolet light.

1 is a schematic block diagram of an exposure apparatus according to an embodiment of the present invention. The schematic block diagram which shows the environment control apparatus of this embodiment. The top view of a nozzle. The perspective view of a nozzle. The figure which shows the flowchart of the manufacture example of devices (semiconductor elements, such as IC and LSI, a liquid crystal display element, an image pick-up element (CCD etc.), a thin film magnetic head, a micromachine, etc.). The figure which shows an example of the detailed flow of FIG.5 S104 in the case of a semiconductor device. The top view which shows the conventional contaminant removal apparatus.

Explanation of symbols

  EL ... exposure light, PL ... projection optical system, R ... reticle, RST ... reticle stage, W ... wafer, WST ... wafer stage, 11 ... exposure apparatus, 12 ... light source, 13 ... illumination optical system, 14 ... exposure apparatus body ( Exposure apparatus main body), 18 ... pollutant removal device, 21 ... optical element, 22 ... optical element (optical element closest to the wafer W (substrate)), 23 ... lens barrel, 25 ... nozzle, 26 ... duct, 27 ... fan (Suction mechanism), 31 ... suction port, 33 ... duct connection, 34 ... pressure feeding device (forced circulator), 36 ... air circulation pipe, 40 ... wafer chamber, 87 ... local circulation system (gas circulation device), 100 ... Environmental control device 101 ... Main body chamber 102 ... Air conditioning unit 110 ... Exposure room 121 ... Circulation path 125 ... Contaminant removal mechanism

Claims (9)

An exposure apparatus having a chamber for housing an exposure apparatus main body, supplying a gas into the chamber for controlling the environment in the chamber, and an environment control apparatus for controlling a flow of the gas supplied into the chamber The contaminant removing apparatus removes the contaminants adhering to the surface of the optical element closest to the substrate of the projection optical system of the exposure apparatus by sucking and removing the contaminants with at least one suction port arranged in the vicinity of the optical element. And
The pollutant removing device, wherein the at least one suction port is provided on the downstream side of the optical element in the gas flow direction. 2. The contaminant removal apparatus according to claim 1, wherein a plurality of the suction ports are disposed at different positions on the downstream side with respect to the optical element, and the contaminants are sucked together with the gas from the suction ports. The suction port is connected to a duct that discharges the gas containing the contaminant sucked from the suction port to the outside of the chamber, and the duct is provided with a suction mechanism for increasing the suction force by the suction port. The pollutant removing device according to claim 1 or 2, wherein the pollutant removing device is provided. The contaminant removal apparatus according to claim 3, wherein the suction mechanism includes a fan. The contaminant removal apparatus according to claim 4, wherein the fan is provided in the chamber. A gas circulation device is provided for returning the gas in the chamber sucked together with the pollutant to the chamber again after removing the pollutant contained in the gas when sucking the pollutant. The pollutant removal apparatus according to any one of claims 1 to 5. The pollutant removing device according to claim 6, wherein the gas circulation device includes a forced circulator that sucks and pumps the gas. An exposure apparatus comprising the contaminant removal apparatus according to claim 1. In a device manufacturing method including a lithography process,
A device manufacturing method, wherein exposure is performed using the exposure apparatus according to claim 8 in the lithography process.

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