JP5936328B2 - Exposure apparatus and device manufacturing method - Google Patents

Description

  The present invention relates to an exposure apparatus that can be used for gas measurement and a device manufacturing method.

2. Description of the Related Art Conventionally, an exposure apparatus that supplies a predetermined gas to an optical path of exposure light is known for the purpose of improving exposure light transmittance. For example, Patent Document 1 discloses an exposure apparatus that purges a predetermined gas in an exposure optical path in order to keep the oxygen concentration present in the optical path low. For example, Patent Document 2 discloses that in an exposure apparatus that purges such a predetermined gas, the purged gas is acquired and measured through a through hole on the measurement substrate. This makes it possible to measure gas in a state close to that during actual exposure.
In such an exposure apparatus that performs exposure by purging a predetermined gas, stable exposure is possible because the gas concentration in the exposure region on the substrate or the region including the periphery thereof is not less than a predetermined value and there is little variation. Is important for. Therefore, it is required to accurately measure the gas concentration in the exposure region on the substrate or in the region including the periphery thereof.

JP 2005-150533 A Japanese Patent No. 3198429

  However, the technique disclosed in Patent Document 1 does not mention improving the measurement accuracy of the concentration of a predetermined gas in the exposure region on the substrate. Moreover, in the technique disclosed in Patent Document 2, the position of gas concentration measurement is fixed. For this reason, there is a problem that the gas concentration cannot be measured at an arbitrary position in the exposure area or the area including the periphery thereof. SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus capable of measuring a gas concentration at an arbitrary position in an exposure region or a region including the periphery thereof.

An exposure apparatus according to one aspect of the present invention is an exposure apparatus that exposes a substrate by projecting a pattern formed on an original onto a substrate by a projection optical system, and moves the substrate while holding the substrate. movable stage is, the atmosphere obtained movement stage from between the projection optical system has an acquisition unit that leads to a measuring instrument for measuring the concentration of a specific gas contained in the atmosphere, the acquisition unit includes an acquisition port for acquiring the atmosphere, a through hole for guiding the atmosphere obtained from the acquired port into the measuring device, through-hole formed in the movable stage, the to hold the substrate during exposure It is an adsorption hole for adsorbing a substrate .

  The present invention can provide an exposure apparatus capable of measuring a gas concentration at an arbitrary position in an exposure area or an area including the periphery thereof.

It is sectional drawing which showed the gas measuring device 5 of embodiment of this invention. It is sectional drawing which showed the gas measuring device 5 of 2nd Embodiment of this invention. It is a flowchart explaining the exposure method of 3rd-5th embodiment of this invention. It is an example of arrangement | positioning of the acquisition port in the modification 1. FIG. It is an example of arrangement | positioning of the acquisition port in the modification 2. It is a flowchart which shows the exposure method of 6th Embodiment. It is an example of the exposure apparatus of 7th Embodiment of this invention. It is a flowchart explaining the exposure method of 7th Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a view showing an exposure apparatus to which a measuring device 5 for measuring the concentration of an atmosphere containing a predetermined gas (for example, nitrogen) according to an embodiment of the present invention is connected. The exposure apparatus illuminates an original (reticle) with exposure light from a light source, and projects and exposes a pattern formed on the original onto a resist on a substrate via a projection optical system 1. As the substrate, a wafer, a glass substrate or the like can be considered. The space between the projection optical system 1 and the substrate 2 is supplied with a predetermined gas by a gas supply means. Further, the periphery of the projection optical system 1 and the substrate 2 is not shown in the drawings as needed, for example, to quickly fill the space between the projection optical system 1 and the substrate 2 or to suppress gas mixture from the periphery. It may be covered with an enclosure.

In the present embodiment, the substrate 2 is fixed to the substrate chuck 3 which is a substrate holding means by the suction force from the substrate suction line 9. Further, the substrate chuck 3 is fixed to a moving stage 4 that moves (scans) in the horizontal direction during exposure by the suction force from the suction line 10 of the substrate chuck. The suction force is generated by a pump connected to the suction holes such as the substrate suction line 9 and the suction line 10. The substrate chuck 3 and the substrate 2 have through holes 11 and 12 for acquiring an atmosphere between the projection optical system 1 and the moving stage 4 (more specifically, a space between the projection optical system 1 and the substrate 2). Are provided. The atmosphere acquisition line 13 serving as an atmosphere acquisition path (acquisition unit) includes the through holes 11 and 12. The gas acquisition line 13 is connected to a measuring instrument 5 that measures the atmosphere. Here, measuring the atmosphere means measuring the concentration of a gas such as oxygen or nitrogen contained in the atmosphere.

  As an example of the present embodiment, the acquisition of the atmosphere in the space between the projection optical system 1 and the moving stage 4 is realized by the through holes 11 and 12 arranged on the moving stage 4 as shown in FIG. Thereby, the communicating through holes 11 and 12 move with the moving stage 4. In the case where the end portions of the through holes 11 and the through holes 12 that are in communication, that is, the end portions that are on the same plane as the projection optical system 1 side surface of the through holes 12 of the substrate 2 acquire the atmosphere. It becomes the acquisition port that is the entrance. That is, the acquisition port is provided so as to face the projection optical system 1 and moves together with the moving stage 4.

  Further, the communicating through-hole 11 and the through-hole 12 are further connected to and communicated with a through-hole serving as a gas passage provided in the moving stage 4. It is desirable that a part of the acquisition line 13 that is the acquisition path be configured to be deformable, such as by using a tube made of an elastic body that can move with the moving stage 4. In that case, by taking out the acquisition line 13 that is the acquisition path from the lower part of the moving stage 4, the influence of the air flow due to the deformation of the acquisition line 13 is not easily transmitted to the vicinity of the acquisition port that is the acquisition surface of the atmosphere. Although the through hole 11 of the substrate chuck 3 is illustrated as a straight line in FIG. 1, it does not necessarily have to be a straight line as long as it penetrates so that an atmosphere can be obtained. For example, a bent hole may be used. good. That is, the through hole 11 of the substrate chuck 3 may be configured to communicate the through hole 12 of the substrate 2 and the through hole for substrate adsorption of the moving stage 4. The same applies to other embodiments described later.

  When measuring the concentration of gas, the atmosphere on the surface of the substrate 2 can be acquired by opening the atmosphere acquisition line 13 and sucking air into the measuring instrument 5 that measures the atmosphere.

  Furthermore, by moving the atmosphere acquisition port together with the moving stage 4 to an arbitrary position in the exposure area, it is possible to acquire gas at an arbitrary position in the entire exposure area or in the area including the periphery thereof. Thereby, the exposure apparatus of this embodiment can measure the distribution of the gas concentration at a more detailed position than when the atmosphere acquisition port is fixed.

  In addition, by acquiring the atmosphere while driving the moving stage 4 and the atmosphere acquisition port at the same speed / acceleration / direction as in the actual exposure state, the influence of the movement of the moving stage 4 on the airflow is taken into consideration. It is possible to measure the distribution of the gas concentration of the gas contained in.

  Further, by providing the through hole 12 in the substrate 2 and using it as an acquisition port, the surface of the substrate 2 can be used in a state where the surrounding atmosphere by the nozzle is relatively small as compared with the case where gas is acquired by arranging a dedicated nozzle. It is possible to acquire the atmosphere of the.

  If the measuring instrument 5 that measures the atmosphere is sufficiently small, the measuring instrument 5 may also be arranged to move with the moving stage 4. However, from the viewpoint of reducing the transport weight of the moving stage 4, the measuring instrument 5 is fixed to a location different from the moving stage 4 and is connected to the through holes 11 and 12 via the acquisition line 13. Embodiments are more desirable.

  When the gas supplied is a mixed gas (mixed gas), the measuring device 5 may measure only one of the mixed gases. For example, when supplying a gas in which nitrogen and oxygen are mixed at a certain ratio for the purpose of making the upper surface of the substrate 2 in a low oxygen state as compared with the normal atmosphere, the nitrogen concentration of the atmosphere acquired from the acquisition port may be measured. The oxygen concentration may be measured.

  Further, the humidity of the gas acquired from the acquisition port may be measured and used as a parameter of a correction table described later.

  In FIG. 1, only one system is shown for the acquisition line 13 and the measuring instrument 5 which are the acquisition paths of the atmosphere including the through holes 11 and 12, but a plurality of acquiring lines and a plurality of measuring instruments connected thereto are shown. You may arrange. When multiple acquisition lines and measuring instruments connected to them are arranged, the measurement time is shortened by measuring simultaneously on multiple lines, compared with the case where many positions are set while moving the moving stage in one system. The In addition, if it is a configuration of multiple acquisition lines and multiple measuring instruments connected to it, measure the concentration of the gas contained in the atmosphere at a location where the relative position with the substrate is different, such as the edge of the substrate or the center of the substrate, This has the effect of improving the accuracy of overall density prediction.

  By branching the atmosphere acquisition line 13 and connecting it to a plurality of measuring instruments 5, the concentration of a plurality of types of gases contained in the atmosphere is measured for the atmosphere acquired from one through hole 11, 12. May be. Thereby, while suppressing the space which arrange | positions the through-holes 11 and 12, the density | concentration of both the gas replaced with the supplied gas can be measured and there exists an effect that the prediction precision of a gas density | concentration goes up.

  Only the portion of the acquisition port of the acquisition line 13 shown in the present embodiment, or the through holes 11 and 12 themselves may be made of a porous material through which the atmosphere can pass. Examples of the porous material through which gas can pass include graphite and seraphite. By providing (inserting) a porous material in the through holes 11 and 12 in an exchangeable manner, it is possible to have a filter function.

  In FIG. 1, the example in which the through hole 12 is provided in the substrate 2 and the through hole 11 is provided in the substrate chuck 3 in order to acquire the atmosphere has been described. However, there are cases where it is difficult to arrange the through holes 12 and 11 in the substrate 2 and the substrate chuck 3 used at the time of exposure due to restrictions such as an empty space of the pattern. In that case, a tool dedicated to measuring the concentration of the gas contained in the atmosphere is used. Specifically, a substrate (tool substrate) as a dedicated tool used when acquiring the atmosphere, a substrate chuck (tool substrate chuck) as a dedicated tool for holding the tool substrate used when acquiring the atmosphere, or both Is used.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, a tool 6, which is a dedicated tool provided with a through hole 11 for acquiring an atmosphere, is arranged on the moving stage 4. The tool 6 is fixed to the moving stage 4 by the suction force from the suction line 10 of the substrate chuck that holds the substrate during exposure. In the first embodiment, “substrate 2” or “tool substrate” is required, whereas in the second embodiment, “substrate 2” or “tool substrate” is not used. For this reason, in 2nd Embodiment, it is not necessary to adsorb | suck the board | substrate 2 or a tool board | substrate, and it becomes possible to divert the board | substrate adsorption | suction line 9 to the line for acquisition of atmosphere. As a result, the substrate suction line 9 is branched and connected to the measuring instrument 5 that measures the atmosphere, so that there is an advantage that it can be applied to an existing exposure apparatus and does not require the addition of a new line. That is, the second embodiment is characterized in that the substrate suction line 9 of the exposure substrate at the time of exposure is also used as the acquisition path. An acquisition port serving as an entrance to the atmosphere of the acquisition path is provided on a surface facing the projection optical system 1 of the tool. That is, the end of the through hole 11 is an acquisition port.

  Moreover, it is preferable that the height of the upper surface of the tool 6 and the height of the upper surface (exposure surface) of the substrate at the time of exposure match or substantially match. Thereby, the atmosphere acquisition position is substantially the same as the substrate surface in actual exposure, and there is an advantage that the concentration of the gas to be measured contained in the atmosphere on the substrate surface in actual exposure can be predicted more accurately.

  It is desirable that the upper surface of the tool 6 has a shape that matches the substrate size used for actual exposure. Thereby, since the difference in the airflow between the acquisition of the atmosphere and the actual exposure can be reduced, there is an advantage that the concentration of the measurement target gas contained in the atmosphere during the exposure can be predicted more accurately.

  FIG. 2 shows an example in which the substrate adsorption line 9 is branched and connected to the measuring instrument 5 that measures the atmosphere. However, the substrate adsorption line 9 is connected to the measuring instrument 5 that measures the atmosphere when measuring the gas concentration. However, the connection may be restored and used during exposure.

(Modification 1)
As a first modification, an example of arrangement of acquisition ports in the second embodiment will be described with reference to FIG. FIG. 4 is an example of the arrangement of acquisition ports in the present invention. FIG. 4A is a view of the tool 6 as viewed from the projection optical system 1 side in FIG. The moving stage 4, the substrate suction line 9, the substrate chuck suction line 10, and the measuring device 5 for measuring the gas contained in the atmosphere are not shown.

  FIG. 4A is a diagram in which a total of 25 through holes 11 of 25 × 5 are available, and each through hole 11 is connected to 25 different lines of acquisition lines 13 and measuring instruments 5. By doing so, it becomes possible to measure the concentration of the gas contained in the atmosphere from a plurality of locations at the same time. That is, it can be considered that there are 25 substrate suction lines 9 illustrated in the second embodiment as the acquisition lines 13. Further, it may be considered that the substrate adsorption line 9 and 24 exclusive acquisition lines 13 shown in the first embodiment are provided. FIG. 4A shows, as an example, five through-holes 11 with respect to an atmosphere acquisition region (five rectangular regions in the figure) arranged at five positions apart from the periphery and the center on the tool 6. The example provided one by one is shown. The gas concentration measurement time can be shortened by measuring the gas concentration by simultaneously acquiring the gas from the plurality of through-holes while moving the moving stage 4.

  4B is a cross-sectional view showing the tool 6 and the sealing chip 14 in the vicinity of the cross-sectional line 16 shown in FIG. FIG. 4B shows an example in which each through hole 11 in each acquisition region is integrated into the acquisition line 13 that is one acquisition path in the middle, unlike the description of the 25 individual systems described above. Yes. In such a configuration, the number of acquisition lines 13 is reduced, so that the exposure apparatus can be easily manufactured. Further, the gas concentration information at 25 locations cannot be obtained by integrating with the acquisition line 13, but there is an averaging effect by the through holes 11 at a plurality of locations by integrating. A groove (a concave rectangular hole) for fitting the sealing chip 14 is provided on the upper surface of the tool 6 shown in FIG. A through hole 11 is provided on the bottom surface of the groove, and is connected to a measuring instrument 5 that measures the atmosphere via an atmosphere acquisition line 13.

  FIGS. 4C, 4D, and 4E are diagrams showing examples of the sealing chip 14 that is fitted into the groove. Concentration measuring points 7A to G are a through-hole or a porous material from which gas can be obtained, and are aligned with the through-hole 11 when the sealing tip 14 is fitted in the groove of the tool 6. .

  When the sealing chip 14 shown in FIG. 4C is used, the atmosphere can be acquired using all the 25 through holes 11 arranged on the upper surface of the tool 6. When the sealing chip 14 shown in FIG. 4D is used, the atmosphere can be acquired using a total of five of the 25 through holes 11 arranged on the upper surface of the tool 6. More specifically, each of the five through holes 11 in each of the acquisition regions described above is used in each of four through holes 11 at four corners other than the center, for a total of five. In the example shown in FIG. 4D, the concentration measurement point 7F can be selected from four locations with simple changes by the front and back of the sealing chip 14 and the rotation. When the sealing chip 14 shown in FIG. 4E is used, the atmosphere is acquired using five of the 25 through holes 11 arranged on the upper surface of the tool substrate chuck 6 at the center of each acquisition region. Is possible.

  In the above description, the case where only one type of sealing chip 14 is applied is described. However, the shape of the sealing chip 14 applied in each groove may be changed. Further, the diameters of the concentration measurement points 7A to G may be changed. When the diameter is increased, there is an effect that more gas can be quickly acquired in a short time.

  Examples of the method for fixing the sealing chip 14 to the tool 6 include bolt fixing, fitting, fixing by an adhesive, fixing by a magnet, fixing by adsorption, fixing by a leaf spring, and the like.

  As described above, the first modification has an advantage that the number of gas concentration measurement points and the relative position of the gas concentration measurement points with respect to the tool 6 can be easily changed by preparing a plurality of types of sealing chips. .

  The groove for fitting the sealing chip 14 may be eliminated and the sealing chip 14 may be used without the sealing chip 14. However, in that case, in order to change the number of concentration measurement points of the gas contained in the atmosphere and the relative position with respect to the tool 6, it is necessary to replace the tool 6 with the position of the through hole 11 changed.

(Modification 2)
As a modified example 2, an arrangement example of acquisition ports in the second embodiment will be described with reference to FIG. FIG. 5 is an example of the arrangement of acquisition ports in the present invention. In the first modification, the tool 6 is a single member, whereas in the second modification, as shown in FIG. 5A, the tool 6 is divided into a tool 6A and a tool 6B.

The tool 6B is provided with a groove (concave hole) for fitting the sealing chip 14. The tools 6A and 6B are arranged so that the through-holes 11 are connected at a contact portion, and form a part of an acquisition line 13 that is an atmosphere acquisition path (acquisition unit) . As shown in FIG. 5D or FIG. 5E, the O-ring 15 is used to keep the contact portion airtight.

  The tool 6A side is fixed in the same manner as the fixing method of the moving stage 4 (not shown in FIG. 5) and the substrate chuck used as a substrate holding member at the time of exposure. The relative position between the moving stage 4 and the tool 6A is fixed. On the other hand, the relative position in the rotational direction of the tools 6A and 6B can be changed by sliding the O-ring contact portion. Thereby, as shown in FIG. 5B, the relative position of the atmosphere acquisition port with respect to the moving stage 4 can be easily changed by changing the relative position of the tool 6 </ b> B with respect to the moving stage 4. it can.

  In the second modification, the case where the O-ring is used to maintain the airtightness of the contact portion between the tools 6A and 6B has been described, but a rubber seal or a mechanical contact may be used as necessary. Further, a friction reducing functional material such as a mechanical bearing, an air bearing, a magnet levitation, and grease application may be added to the sliding portion.

  FIG. 5C shows an example of the sealing chip 14 in the second modification. In Example 1, the density | concentration measurement point 7 can be moved to arbitrary rotation angles by making circular the chip | tip 14 for sealing, while making it circular. In this case, the structure of the bottom surface of the groove (concave circular hole) into which the sealing chip 14 is fitted needs to be configured so that the atmosphere can be taken in without depending on the arbitrarily set angle of the sealing chip 14. As in (c) to (e) of FIG. 4, a plurality of types of sealing chips 14 in which the number and arrangement of the through holes are changed may be used.

  In order to change the relative position between the tool substrate chucks 6A and 6B and the relative position between the tool 6B and the sealing chip 14, a drive source may be arranged. Examples of the driving source include an ultrasonic motor, a rotary motor, a flagellar motor, a pneumatic actuator, and a piezo actuator.

  As described above, as two modified examples, the sealing chip 14 has been described as a rectangular plate or a circular plate. However, the sealing chip 14 may have a conical shape, or may be provided with notches, protrusions, or positioning pins. Good.

[Third Embodiment]
Next, a third embodiment of the present invention will be described based on FIG. FIG. 3 is an example of a flowchart of the exposure method of the present invention. The present embodiment is characterized in that the exposure time is changed by calculating the optimum exposure condition from the gas concentration measurement result by the gas measuring device 5 described above.

In the example shown in FIG. 3, the gas concentration is measured in advance according to the flow shown in FIG. 3A, a correction table is created based on the result, and then the flow shown in FIG. Just before actual exposure, only parameter adjustment based on the correction table is performed. This has an advantage that a decrease in throughput of the exposure apparatus due to the measurement of the gas concentration can be suppressed as compared with “when the gas concentration measurement is performed every time during exposure”. This flowchart Ru is executed by a computer. This computer functions as acquisition means for acquiring the exposure amount required at the time of exposure.

  For the description of the exposure amount changing method of the present embodiment, an example of parameters and effects thereof will be described in the case of using a resist whose exposure sensitivity decreases and the exposure time increases when the oxygen concentration increases. For example, as a result of measuring the gas concentration, the exposure time is shortened for shots with a low oxygen concentration, and the exposure time is lengthened for shots with a high oxygen concentration. It becomes possible to reduce magnification and shape variation.

  The gas concentration change between shots has been described above as a representative example. However, it is also effective to apply the present invention to the gas concentration change in the shot and the gas concentration change between the substrates.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described based on FIG. The present embodiment is characterized in that the optimum exposure condition is calculated from the gas concentration measurement result by the gas measuring device 5 to change the illuminance distribution.

  An example of parameters and their effects will be described in the case of using a resist in which the exposure sensitivity decreases and the exposure time increases as the oxygen concentration increases. For example, by reducing the illuminance for shots with a low oxygen concentration and increasing the illuminance for shots with a high oxygen concentration, it is possible to align the degree of photosensitivity in each shot and suppress magnification and shape variations between shots. Become.

  Illuminance changing means includes means for changing the illuminance of a light source or creating an illuminance distribution correction filter and arranging it in the middle of the optical path. The illuminance distribution correction filter corrects the illuminance distribution by inserting a uniform correction filter in a part of the simultaneously exposed area, or inserts a filter capable of forming an illuminance distribution in the entire exposed area. May be.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described based on FIG. The present embodiment is characterized in that the scan speed is changed to an optimum scan speed based on the gas concentration measurement result by the gas measuring device 5 described above.

An example of parameters and their effects will be described in the case of using a resist in which the exposure sensitivity decreases and the exposure time increases as the oxygen concentration increases. For example, if the oxygen concentration is low immediately after the start of exposure for one exposure shot and the oxygen concentration is high immediately before the end of exposure, exposure without correction will result in a line that is more sensitive to light immediately after the start of shot exposure than immediately before the end of exposure. The width tends to increase. For this reason, distortion occurs when correction is not performed. On the other hand, by increasing the scanning speed of the moving stage immediately after the start of shot exposure and correcting the moving stage to be slower immediately before the end of the shot, the degree of photosensitivity in the shot is made uniform and distortion occurs. The amount can be reduced.

  In the description of the third to fifth embodiments using FIG. 3, the example in which the gas concentration measurement and the correction table are created in advance and then only the parameter adjustment based on the correction table is performed immediately before the exposure is performed. The present invention is effective even when the gas concentration measurement is performed immediately before exposure. In this case, since correction based on the concentration distribution immediately before exposure can be performed even in an environment where the gas concentration distribution is not reproducible, there is an advantage that the correction accuracy is increased.

  That is, the third embodiment, the fourth embodiment, and the fifth embodiment all generate information on the exposure amount required for exposure at a plurality of positions on the exposure substrate that is exposed during exposure, thereby exposing the substrate. Is described in detail. In summary, as an exposure amount changing means, illuminance change such as moving the position of the light source itself, or illuminance distribution correction filter, control of exposure amount by scan speed is exemplified, but it is not limited to this. Absent.

[Sixth Embodiment]
The setting of the correction table and the exposure operation of the exposure apparatus will be described in detail with reference to FIG. FIG. 3 exemplarily shows only the outline of the creation of the correction table and the accompanying exposure operation. Here, the operation and control of the exposure apparatus performed in each step will be described in detail. The process of the flowchart of FIG. 6 is a little different from the flow of FIG. 3, but is essentially equivalent. The flowchart of FIG. 6 is also configured as a program executed while controlling the exposure apparatus with command commands or the like as appropriate in a microcomputer in the exposure apparatus or an external computer for performing various settings in the exposure apparatus, as in the flowchart of FIG. Is done.

  According to the flowchart shown in FIG. 6A, the gas concentration is measured before actual wafer exposure, and a correction table necessary for wafer exposure is created. First, in step S601, a predetermined gas (for example, nitrogen) is supplied to a space between the projection optical system 1 and the moving stage 4 by a predetermined amount using a gas supply unit (not shown). More specifically, in the first embodiment, a predetermined gas is supplied to the space between the substrate 2 and the projection optical system 1, and in the second embodiment, the space between the tool 6 and the projection optical system 1 is supplied. . This may be supplied as a predetermined gas alone or as a mixed gas whose concentration of the predetermined gas is known.

  In step S602, by moving the moving stage 4, the acquisition port provided integrally on the moving stage is positioned at a desired position where the gas concentration is desired to be measured. In step S603, an atmosphere containing a predetermined gas between the projection optical system 1 and the moving stage 4 is acquired from the acquisition port via the acquisition line 13. In step S604, the concentration of the gas contained in the acquired atmosphere is measured by the measuring device 5, and the value of the measurement result is stored in a storage unit (not shown) that cooperates with the above-described microcomputer or computer.

  Then, steps S602 to S604 are repeated for the required number of measurement points (N places). Here, the concentration of nitrogen exemplified as the predetermined gas may be measured by the measuring device 5, or the concentration of oxygen that should have been reduced by supplying nitrogen into the atmosphere may be measured.

  In step S605, it is determined whether or not the measured gas concentration falls within the set concentration range. Here, it is determined by comparing the values whether the measurement results at each measurement point measured in step S604 are within the prescribed concentration range for each measurement point stored in the storage means linked to the computer. doing. If it is determined in step S605 that the concentration is not within the specified concentration range, the process returns to step S601, and a predetermined gas is further supplied by the gas supply unit, and the above-described operation is repeated.

  If it is determined in step S605 that the measurement result at each measurement point measured in step S604 is within the specified density range stored in the storage means, the exposure amount required for exposure in step S606. Is obtained by calculation. In step S606, an optimum exposure amount is obtained for the value measured in step S604. In step S607, the exposure time optimized for the exposure amount obtained in S606 and the optimized illuminance distribution are obtained by calculation. The exposure time and illuminance distribution are obtained based on the same concept as described in the third and fourth embodiments. In step S608, information on exposure time, illuminance, and scan speed is stored in the storage means for each shot position as a correction table. Here, the illuminance and illuminance distribution correction filter information in each shot (for each position in the shot) are simultaneously created and stored. Regarding the scan speed, the idea of the fifth embodiment described above can be applied.

  The actual wafer exposure is executed based on steps S611 to S614 in the flowchart shown in FIG. First, in step S611, necessary exposure preparation such as wafer transfer is started. In step S612, the illuminance distribution correction filter is replaced based on the illuminance distribution correction filter information created in step S608 of FIG. In step S613, exposure control parameters necessary for wafer exposure are set based on the information in the correction table created in step S608. Here, parameters such as exposure time and scan speed are set. In step S613, the supply of gas based on information on the amount of a predetermined gas supplied until a correction table is further created (until determined as Yes in step S605) is started. In step S614, wafer exposure is started.

[Seventh Embodiment]
FIG. 7 shows a specific gas contained in the space in order to adjust the concentration of a specific gas contained in the atmosphere existing in the space between the projection optical system 1 and the substrate 2 or the tool 6 according to the seventh embodiment of the present invention. It is a schematic diagram of the supply means to supply. Here, for example, the specific gas is oxygen, and the predetermined gas is a gas having a lower oxygen concentration and a higher nitrogen concentration than the atmosphere. That is, in order to lower the oxygen concentration contained in the atmosphere in the space between the projection optical system 1 and the substrate 2 or the tool 6 that was in the same state as the atmosphere, the supply means contains more nitrogen than the atmosphere (less oxygen). The gas is supplied as a predetermined gas by the supply means. Illustratively, oxygen is given as the gas whose concentration is to be lowered, and nitrogen is given as the gas contained in a large amount of the predetermined gas to be supplied. However, the present invention is not limited to this. When it is desired to increase the concentration of a specific gas contained in the atmosphere of the space between the projection optical system 1 and the substrate 2 or the tool 6, a predetermined gas having a high specific gas concentration is supplied.

  The supply means includes a flow rate controller for controlling the flow rate of the gas for changing the supply amount of the predetermined gas to be supplied, and a measurement means for measuring the oxygen concentration of the supplied gas. The supply means, for example, mixes two types of gases (gas A and gas B) having different oxygen concentrations and supplies them to the space between the projection optical system 1 and the substrate 2. When it is desired to lower the concentration of the specific gas oxygen on the substrate 2 or the tool 6 below the atmosphere, at least one of the two kinds of gases described above is a gas having an oxygen concentration lower than the oxygen concentration contained in the atmosphere. Become. The measuring means includes a measuring instrument 5, an acquisition line 18 that is an acquisition path for the gas to be supplied, and the like.

  The gas in the supply path from the location where the two gases are mixed to the space between the projection optical system 1 and the substrate 2 is opened by opening the acquisition line 18 and sucking into the measuring instrument 5 to mix the oxygen of the mixed gas. It is possible to acquire concentration information (oxygen concentration value). Here, it has been described that the concentration is measured by the measuring device 5, but a measuring device different from the measuring device 5 may be separately provided for measurement. Further, when the mixed gases A and B are substantially composed of nitrogen and oxygen, for example, the oxygen concentration can be obtained by measuring the nitrogen concentration with the measuring device 5 instead of the oxygen concentration.

  The mixed gas is always introduced from the arbitrary position of the supply path to the measuring device 5 to measure the oxygen concentration, and the flow rate controllers 17A and 17B are used to adjust the oxygen concentration of the supplied mixed gas to a desired target value based on the measured value. The flow rates of gas A and gas B are controlled. For example, the difference between the oxygen concentration value contained in the atmosphere acquired on the substrate 2 and the oxygen concentration value of the gas acquired from the acquisition line 18 is added to the current target value to obtain a new target value. And gas flow control is performed with a new target value. By repeating the update of the target value, the oxygen concentration on the substrate can be set to a desired oxygen concentration as a result.

  The space between the projection optical system 1 and the substrate 2 may be covered with a partition wall (not shown), and the gas intake position in the supply path may be arranged in the partition wall. The partition only needs to create an environment in which the gas supplied to the space between the projection optical system 1 and the substrate 2 can easily accumulate, and need not be completely separated from the surrounding space. In the case of a partition that completely separates from the surrounding space, an evacuation means is required to replace the supply gas with the gas already present. For this reason, it is desirable that the space between the projection optical system 1 and the substrate 2 and the surrounding space communicate with each other in some part of the partition wall. Although two types of gas are mixed in FIG. 7, the gas to supply may use 3 or more types of mixed gas. Further, the flow rate controller may be arranged only in one type of gas supply path (for example, gas A).

  FIG. 8 is an example of a flowchart of the oxygen concentration adjusting method of the present invention. In the example shown in FIG. 8, the concentration of the atmosphere on the substrate is measured in advance in the flowchart of FIG. 8A, and a correction table such as a flow rate offset for the set value of the oxygen concentration is created based on the result. Thereafter, only the parameter adjustment based on the correction table is performed immediately before the actual exposure in the flow shown in FIG. This has an advantage that a decrease in throughput of the exposure apparatus due to the measurement of the gas concentration can be suppressed as compared with “when the gas concentration measurement is performed every time during exposure”. When resists having different desirable oxygen concentrations at the time of exposure are used, the set concentrations of oxygen concentrations during the exposure are different. This embodiment is particularly effective when the difference between the oxygen concentration on the substrate and the oxygen concentration in the gas supply path is different for each oxygen concentration set value.

  Hereinafter, the flowchart of FIG. 8A will be described in detail. Similarly to the flowcharts of FIGS. 3 and 6, this flowchart is also configured as a program executed while controlling the exposure apparatus in a microcomputer in the exposure apparatus or an external computer for performing various settings in the exposure apparatus. Step S801 is a step of moving the acquisition port for acquiring gas. That is, by driving the moving stage 4, one or each of a plurality of acquisition ports as described in the above-described embodiments is moved to a desired position to prepare for gas concentration measurement.

  In step S802, an oxygen concentration value in a space (particularly the substrate 2) between the projection optical system 1 and the substrate 2 (or the tool 6) and a gas concentration value (for example, oxygen concentration value) of the supplied gas are set. For example, when the predetermined gas to be supplied is a mixed gas of nitrogen and oxygen, it may be set not with an oxygen concentration value but with a nitrogen concentration value. In that case, the concentration value measured by the measuring device 5 may also be the concentration of nitrogen. When the gas component is almost two and the ratio (concentration) is clearly known, such as when the atmosphere is mostly nitrogen and oxygen, the ratio of the other is included even if one of them is measured Is almost exactly known. In step S803, the gas flow rate for the set gas concentration value is determined, and in step S804, gas supply is started using the flow rate controller 17. In step S805, the gas on the substrate 2 is acquired from the acquisition port, and the gas concentration of the gas acquired in step S806 is measured by the measuring instrument 5.

  In step S807, it is determined whether the gas concentration value condition on the substrate 2 or the tool 6 set in step S802 is satisfied. The gas concentration value may be set with a width or may have a predetermined width with respect to the set value.

  If the condition is not satisfied (No) in step S807, the flow rate offset is input in step S808, and the gas is supplied with the flow rate changed. The flow rate offset is an increase / decrease amount that is changed to change the oxygen concentration on the substrate 2 or the tool 6 to a desired concentration with respect to the flow rate of the currently supplied gas. In addition, in the case of a mixed gas in which a plurality of gases are mixed instead of one kind of gas, the flow rate may be increased or decreased from the current flow rate. May be input as a difference between them. This flow rate offset is automatically set with reference to a table of increase / decrease values stored in a storage means (not shown) created from the relationship between the measured oxygen concentration on the substrate 2 or the tool 6 and the flow rate. Alternatively, a display screen that prompts the user to input a flow rate that indicates the measured oxygen concentration, current flow rate, etc. is provided on the computer display screen that accompanies the exposure apparatus. it can. Steps S802 to S808 are repeated (N times) until the condition of S807 is satisfied and the required number of oxygen concentrations is completed.

If the condition is satisfied (Yes) in step S807, an oxygen concentration value and a flow rate offset are set as a correction table (step S809). Here, for example, the value set in step S802 and the gas flow rate set in step S803. In particular, when a mixed gas is supplied, the value is set as the flow rate of each gas. here,
In the flowchart of FIG. 8B, first, exposure preparation is started in step S811. Next, in step S812, gas supply to the substrate 2 or the tool 6 is started based on the correction table set by the flow controller 17, and flow control based on the correction table created in step S809 is performed. . In step S813, exposure is started.

[Device manufacturing method]
Next, device manufacturing methods such as semiconductor integrated circuit elements and liquid crystal display elements using the above-described exposure apparatus will be described as an example. The device undergoes an exposure process for exposing the substrate using the above-described exposure apparatus, a development process for developing the substrate exposed in the exposure process, and another known process for processing the substrate developed in the development process. Manufactured by. Other known processes are etching, resist stripping, dicing, bonding, packaging processes, and the like.

  Even if the first to seventh embodiments and the first and second modifications of the present invention are applied in combination, the present invention is effective.

  The present invention is particularly useful because, in the manufacturing process of a color filter or the like, when exposure is required in a low oxygen state in order to reduce the exposure amount, the resist is exposed by spraying an inert gas such as nitrogen. Even if it is a color resist, blue resist, green resist and red resist have different desired oxygen concentrations during exposure, so it is very effective to create a correction table by measuring them in advance. Function.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

1 Projection optical system 2 Substrate
DESCRIPTION OF SYMBOLS 3 Substrate chuck 4 Moving stage 5 Measuring instrument 6 Tool 7A-D Concentration measuring point 9 Substrate adsorption line 10 Substrate chuck adsorption line 11 Through hole 13 Atmosphere acquisition line (acquisition path)
14 Chip for sealing 15 O-ring 17A-B Flow controller 18 Line for acquiring gas in the supply path

Claims (15)

An exposure apparatus that exposes the substrate by projecting a pattern formed on an original onto the substrate by a projection optical system,
Movement stage that moves while holding the substrate, the atmosphere is obtained from between the projection optical system and the movable stage, the acquisition unit for guiding the measuring instrument for the measurement of the concentration of a specific gas contained in the atmosphere Have
The acquisition unit includes an acquisition port for acquiring the atmosphere, and a through hole that guides the atmosphere acquired from the acquisition port to the measuring instrument,
The exposure apparatus, wherein the through-hole formed in the moving stage is a suction hole for sucking the substrate to hold the substrate during exposure. An exposure apparatus that exposes the substrate by projecting a pattern formed on an original onto the substrate by a projection optical system,
A moving stage that holds and moves the substrate;
Supply means for supplying a predetermined gas between the moving stage and the projection optical system;
To a measuring instrument that includes an acquisition port that moves with the moving stage and acquires an atmosphere between the moving stage and the projection optical system, and that measures the concentration of a specific gas contained in the atmosphere acquired from the acquisition port An acquisition department that leads the atmosphere,
Measuring means for obtaining the predetermined gas from the supply means and measuring the concentration of the specific gas contained in the predetermined gas;
Based on the concentration of the specific gas contained in the atmosphere measured by the measuring device and the concentration of the specific gas contained in the predetermined gas measured by the measurement unit, the predetermined unit supplied by the supply unit An exposure apparatus comprising adjusting means for adjusting the concentration of the specific gas by adjusting the gas.   The acquisition unit includes a through hole provided in a tool held by the moving stage, and the acquisition port is an end of a through hole provided in the tool, and is provided on a surface facing the projection optical system. The exposure apparatus according to claim 1, wherein the exposure apparatus is an exposure apparatus.   4. The exposure apparatus according to claim 3, wherein the height of the surface of the tool facing the projection optical system is the height of the exposure surface of the substrate used during exposure. Based on the measurement result by the measuring device, the exposure amount acquisition unit acquires information related to the exposure amount required for exposure at a plurality of positions on the substrate during exposure, and is acquired by the exposure amount acquisition unit. the exposure apparatus according to any one of claim 1 to 4, wherein the controller controls to expose the exposure amount on the basis of information about the exposure amount. 6. The exposure apparatus according to claim 5 , wherein an illuminance change of a light source is executed as the exposure amount control. 6. The exposure apparatus according to claim 5 , wherein an illuminance distribution correction filter is inserted as the exposure amount control. 6. The exposure apparatus according to claim 5 , wherein the exposure amount is controlled by changing a scan speed of the moving stage. Wherein the predetermined gas, the exposure apparatus according to claim 2, characterized in that the said specific gas concentration is mixed different kinds of gases to each other of the gas contained in the gas. The exposure apparatus according to claim 2, wherein the predetermined gas is a gas containing nitrogen. The exposure apparatus according to any one of claim 1 to 10, wherein the specific gas, characterized in that oxygen. A device manufacturing method comprising: a step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 11 ; and a step of developing the exposed substrate. An exposure method for exposing the substrate by projecting the pattern formed on the original plate onto the substrate by a projection optical system,
Acquiring an atmosphere between the moving stage and the projection optical system from an acquisition port that moves together with the moving stage holding the substrate;
Measure the concentration of a specific gas contained in the atmosphere acquired from the acquisition port,
Obtaining a predetermined gas supplied between the moving stage and the projection optical system to measure the concentration of the specific gas contained in the predetermined gas;
By adjusting the supplied predetermined gas based on the concentration of the specific gas included in the atmosphere acquired from the acquisition port and the concentration of the specific gas included in the predetermined gas An exposure method comprising adjusting the concentration of a specific gas. The difference between the concentration of the specific gas contained in the atmosphere acquired from the acquisition port and the concentration of the specific gas included in the predetermined gas is obtained, and the concentration of the predetermined gas based on the obtained difference The exposure method according to claim 13, wherein the exposure is adjusted. Obtaining the offset of the supply amount of the predetermined gas based on the concentration of the specific gas included in the atmosphere acquired from the acquisition port and the concentration of the specific gas included in the predetermined gas, and determining the offset The exposure method according to claim 13, wherein the supply amount of the predetermined gas is adjusted based on the above.

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