JP2009016404A - Liquid recovery apparatus, immersion lithography, and method of manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid recovery apparatus capable of excellent exposure processing by quickly and accurately measuring a flow rate of a liquid recovered by mixing a gas with the liquid, and reducing an effect due to leakage or intrusion of the liquid; and to provide an immersion lithography. <P>SOLUTION: In a line for mixingly recovering a gas (g) and a liquid (f), liquid recovery apparatus 20 and 21 for measuring a flow rate of only the liquid have recovery tubes 17 and 18 being one or more recovery lines for mixingly recovering the gas (g) and the liquid (f); a depressurization tank 22 is a depressurized vessel inserted with the recovery tubes 17 and 18; a liquid reception vessel 23 is arranged in the depressurization tank 22, and receives the liquid (f) discharged from the recovery line; drain piping 24 is connected to a bottom part of the liquid reception vessel 23; a flow rate sensor 26 being a flow rate detection part is arranged in an intermediate part of the piping 24, and measures the flow rate of the liquid (f); and at least part of a part of the piping 24 downstream of the flow rate sensor 26 is arranged above the flow rate sensor 26. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an immersion exposure apparatus that exposes a substrate through a liquid supplied between a final lens of a projection optical system and the substrate.

In a manufacturing process of a semiconductor device composed of an ultrafine pattern such as LSI or VLSI, a reduction type projection exposure apparatus is used that reduces and projects a pattern formed on a mask onto a substrate coated with a photosensitive agent. ing.
As the integration density of semiconductor devices has increased, further miniaturization of patterns has been demanded, and at the same time as the development of resist processes, the miniaturization of exposure apparatuses has been addressed.
As means for improving the resolving power of the exposure apparatus, a method of shortening the exposure wavelength and a method of increasing the numerical aperture (NA) of the projection optical system are generally used.
The exposure wavelength is shifting from the i-line at 365 nm to ArF excimer laser light having an oscillation wavelength near 193 nm, and further, a fluorine (F2) excimer laser having an oscillation wavelength near 157 nm is being developed.

On the other hand, a projection exposure method using an immersion method has attracted attention as a resolution enhancement technique that is completely different from these.
Conventionally, the space between the final surface of the projection optical system (the light exit surface of the final lens) and the surface of the substrate to be exposed (for example, the wafer) is filled with gas. In the immersion method, this space is filled with liquid. Satisfy and perform projection exposure.
The advantage of the immersion method is, for example, that the liquid provided in the space between the projection optical system and the wafer is pure water (refractive index n1.44 for light having a wavelength of 193 nm).
When it is assumed that the maximum incident angle of the light beam that forms an image on the wafer is the same between the immersion method and the conventional method, the resolution of the immersion method is improved 1.44 times that of the conventional method even if a light source having the same wavelength is used. That is.
This is equivalent to increasing the NA of the projection optical system of the conventional method by 1.44 times. According to the immersion method, it is possible to obtain a resolution of NA = 1 or higher, which is impossible with the conventional method.

One of the methods for filling the space between the final surface of the projection optical system and the wafer surface with the liquid is a local fill method in which the liquid is allowed to flow only in the space sandwiched between the projection optical system and the wafer surface.
In the local fill method, liquid is supplied to an open area between the final lens surface of the projection optical system and the wafer surface, and the liquid is collected by vacuum suction so that the liquid does not spill out of the stage. At this time, the gas in the atmosphere is sucked together with the liquid under reduced pressure.
The gas sucked together with the liquid under reduced pressure is separated into a liquid and a gas by the gas-liquid separator, and the separated liquid is transferred to the liquid recovery unit.
Japanese Patent Application Laid-Open No. 2005-159322 (Patent Document 1) discloses an immersion exposure apparatus that measures a flow rate by arranging a flow meter in the middle of a pipe connecting a gas-liquid separator and a liquid recovery unit to measure a flow rate. It is disclosed.
JP 2005-159322 A

In the above-described conventional immersion exposure apparatus, the liquid and the gas recovered by the vacuum suction are separated from each other by the gas-liquid separator, and the separated liquid is transferred to the liquid recovery unit.
There are capacitive, Karman vortex, electromagnetic, ultrasonic, and Coriolis methods for detecting the liquid flow rate. In either case, in order to accurately measure the liquid flow rate, only the liquid is guided to the flow meter. Must-have.
A mechanism for transferring only the liquid to the liquid recovery unit is necessary. For example, it has means for measuring the liquid level of the liquid accumulated at the bottom of the gas-liquid separator.
Furthermore, there is a method for controlling the transfer of the liquid so that the liquid level is always a constant height at a position higher than the drain outlet for draining the liquid from the gas-liquid separator to the liquid recovery section.
In this method, it is possible to transfer only the liquid to the flow meter. However, the gas-liquid separator requires a large capacity compared to the flow rate of the liquid to be recovered. With a capacity of
Since the amount of change in the liquid level stored at the bottom of the gas-liquid separator becomes smaller as the capacity of the gas-liquid separator increases, the liquid transfer is delayed.
Therefore, the delay in flow rate detection delays the determination of abnormality even when the liquid recovery flow rate is extremely reduced, and the amount of liquid that could not be recovered leaks from under the projection lens increases. Failure, leakage, rust, etc. may occur. In this case, the exposure process cannot be performed satisfactorily.
Accordingly, the present invention provides a liquid recovery apparatus that measures the flow rate of liquid recovered by mixing gas and liquid quickly and accurately, reduces the influence of liquid leakage or intrusion, and enables good exposure processing. It is another object of the present invention to provide an immersion exposure apparatus.

  The liquid recovery apparatus of the present invention for solving the above-mentioned problems is one or more recovery lines in which gas and liquid are mixed and recovered, a decompression tank to which the recovery line is connected, and the inside of which is decompressed, A liquid receiver provided in the vacuum tank and receiving the liquid discharged from the recovery line; a drain line connected to a bottom of the liquid receiver and discharging the liquid into the vacuum tank; A flow rate detection unit that is provided in the middle of the drainage line and measures the flow rate of the liquid, and at least a part of a portion of the drainage line that is downstream of the flow rate detection unit is the flow rate detection unit. It arrange | positions more upwards, It is characterized by the above-mentioned.

  Furthermore, the exposure apparatus of the present invention is an exposure apparatus that exposes the substrate through a liquid supplied between a final lens (a lens closest to the substrate among a plurality of lenses) of the projection optical system and the substrate. A supply line for supplying the liquid under the final lens, a valve provided in the middle of the supply line for controlling the flow of the liquid, a control unit for controlling opening and closing of the valve, and the liquid recovery And a device.

  According to the present invention, the flow rate of the liquid recovered by mixing the gas and the liquid is measured quickly and accurately, the influence of the leakage or intrusion of the liquid is reduced, and a good exposure process is possible.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, an immersion exposure apparatus according to an embodiment of the present invention will be described with reference to FIG.
The embodiment of the present invention is an immersion exposure apparatus that exposes a wafer 9 through a liquid f supplied between the final lens of the projection optical system 4 closest to the wafer 9 as a substrate and the wafer 9.
A supply pipe 16 serving as a supply line supplies the liquid f under the final lens. The valve 29 is provided in the middle of the supply pipe 16 that is a supply line, and controls the flow of the liquid f. The liquid immersion control device 19 that is a control unit controls the opening and closing of the valve 29.
Furthermore, it has the liquid collection | recovery apparatuses 20 and 21 of Example 1-4 of this invention shown by FIGS.
In the first embodiment, the pipe 24 that is a drainage line is connected to the bottom of the liquid receiver 23, and discharges the liquid f into the decompression tank 22 from the discharge port 27.
The flow rate sensor 26 that is a flow rate detection unit is provided in the middle of the pipe 24 that is a drainage line, and measures the flow rate of the liquid f.
Furthermore, in the first embodiment, at least a part of a portion of the pipe 24 that is a drainage line that is downstream of the flow rate sensor 26 that is the flow rate detection unit is disposed above the flow rate sensor 26 that is the flow rate detection unit. .
The flow rate sensor 26 which is a flow rate detection unit is provided inside the decompression tank 22 and is a capacity type flow rate sensor.
By setting the drain port 27 at a position higher in the gravity direction 100 than the flow rate sensor 26, the pipe 24 and the flow rate sensor 26 at a position lower in the gravity direction 100 than the drain port 27 are filled with the liquid f.
When the liquid f transferred through the recovery pipe 17 accumulates at the bottom of the liquid receiver 23 and the water surface becomes higher than the drain outlet 27, the liquid f is transferred toward the drain outlet 27 by the action of the mass of the liquid and gravity. .
By reading the movement of the liquid f with the flow sensor 26, the flow rate of the collected liquid is measured accurately and quickly.
For this reason, the flow rate of the liquid f recovered by mixing the gas and the liquid is measured quickly and accurately, the influence of leakage or intrusion of the liquid f is reduced, and a good exposure process is possible.
Since the liquid level at the bottom of the liquid receiver 23 rises by the pressure loss generated when the liquid flows through the pipes 24 and 25 and the flow sensor 26, the end of the recovery pipe 17 is positioned higher than the drain port 27. And
The liquid f drained from the drain port 27 is stored at the bottom of the decompression tank 22 and is discharged through the drain line 8.

Light emitted from an exposure light source (not shown) such as an ArF excimer laser or F2 laser is supplied to the illumination optical system 2.
The illumination optical system 2 illuminates a part of the reticle 1 that is an original with slit light having a cross-sectional shape that passes through the slit, using light supplied from an exposure light source.
While the reticle 1 is illuminated by the slit light, one of the reticle stage 3 that is the original stage holding the reticle 1 and the wafer stage 10 that is the substrate stage holding the wafer 9 that is the substrate is on the other side. Move the scan while synchronizing.
Through such a synchronous scan, as a result, the entire pattern on the reticle 1 is continuously imaged on the wafer 9 via the projection optical system 4, and the resist applied on the surface of the wafer 9 is exposed.
The reticle stage 3 is supported by a surface plate 14, and the wafer stage 10 is also supported by a surface plate 15.

The two-dimensional positions of the reticle stage 3 and the wafer stage 10 are measured in real time by the reference mirror 11 and the laser interferometer 12.
Based on this measurement value, the stage control device 13 performs positioning and synchronous control of the reticle 1 (reticle stage 3) and the wafer 9 (wafer stage 10).
The wafer stage 10 incorporates a driving device that adjusts, changes, or controls the position, rotation direction, and tilt of the wafer 9 in the vertical direction (vertical direction).
At the time of exposure, the wafer stage 10 is controlled by this driving device so that the exposure area on the wafer 9 always matches the focal plane of the projection optical system 4 with high accuracy.
Here, the position of the surface on the wafer 9 (vertical position and inclination) is measured by an optical focus sensor (not shown) and supplied to the stage controller 13.
The exposure apparatus main body is installed in an environmental chamber (not shown), and the environment surrounding the exposure apparatus main body is maintained at a predetermined temperature.

The space surrounding the reticle stage 3, the wafer stage 10, and the laser interferometer 12 and the space surrounding the projection lens 4 are further blown with individually controlled temperature-controlled air to maintain the environmental temperature with higher accuracy. .
In this embodiment, the liquid immersion method for filling the space (gap) between the final lens of the projection optical system 4 and the wafer 9 with liquid is a liquid supply nozzle disposed above the wafer 9 and in the vicinity of the projection optical system 4. 5 and a liquid recovery nozzle 6 disposed outside the liquid supply nozzle 5.
Further, this is realized by a suction port arranged in the wafer stage 10 (not shown).
The exposure apparatus according to the embodiment of the present invention is useful for, for example, any exposure method and exposure apparatus to which an immersion method is used in which ultraviolet light is used as exposure light and the projection optical system and the wafer as the substrate are filled with a liquid. .
Such an exposure apparatus includes, for example, an exposure apparatus that projects and transfers an original pattern onto the substrate while the substrate is stationary, and slits the original pattern onto the substrate while synchronously scanning the substrate and the original. An exposure apparatus that performs scanning exposure is included.

Next, with reference to FIG. 6, the immersion method in the immersion exposure apparatus of the present embodiment and the liquid recovery apparatuses 20 and 21 of the embodiment of the present invention will be described in detail.
The liquid supply nozzle 5 is connected to the liquid supply device 7 via a supply pipe 16. Similarly, the liquid recovery nozzle 6 is connected to a liquid recovery apparatus 20 according to an embodiment of the present invention via a recovery pipe 17 that is a recovery line. Connected with.
The suction port (not shown) is connected to the liquid recovery apparatus 21 of the embodiment of the present invention via a recovery pipe 18 that is a recovery line.
A plurality of liquid recovery devices 20 and 21 may be provided, or a plurality of recovery lines 17 may be connected to the liquid recovery device 20.
The liquid supply device 7 may include, for example, a tank that stores liquid, a pressure feeding device that sends out liquid, a flow rate control device that controls the supply flow rate of liquid, and a control valve that controls supply / stop of liquid.
The liquid supply device 7 preferably further includes a temperature control device for controlling the supply temperature of the liquid.

The liquid recovery devices 20 and 21 of the embodiment of the present invention have a decompression tank 28 for temporarily storing the recovered liquid, a vacuum generator (not shown) for sucking the liquid, and a flow rate sensor 26 for measuring the recovered liquid flow rate.
The liquid immersion control device 19 receives information such as the current position, speed, acceleration, target position, and movement direction of the wafer stage 10 from the stage control device 13.
The liquid immersion control device 19 gives the liquid supply device 7 and the liquid recovery devices 20 and 21 with control commands such as the start and stop of liquid immersion and the flow rate based on these pieces of information.
Further, the liquid immersion control device 19 includes information on the flow rate of the recovered liquid f, which is information from the flow rate sensor 26 that is a flow rate detection unit of the liquid recovery devices 20 and 21, and the flow rate of the liquid f supplied below the final lens. And a comparator 19a that compares the information of the supply flow rate of the liquid supply device 7 as described above.
The comparator 19a has a tolerance for determining an abnormality, and when the information from the flow rate sensor 26 that is a flow rate detection unit is out of the tolerance range, the immersion control device 19 that is a control unit controls the valve 29. Then, the supply of the liquid f under the final lens is stopped.
The exposure apparatus of the present embodiment has a plurality of liquid recovery apparatuses 20 and 21 and each includes a flow rate sensor 26 that is a flow rate detection unit.
Further, the comparator 19a performs tolerance determination based on any one, a plurality of, or all of the information of the flow rate sensor 26 that is one or more flow rate detection units.
Furthermore, the tolerance determination by the comparator 19a may not be performed during a predetermined time after the supply of the liquid f is started.

The liquid f for immersion is selected from those that absorb less exposure light, and it is desirable that the liquid f have a refractive index substantially the same as that of a refractive optical element such as quartz or fluorite.
Specifically, as the liquid f for immersion, pure water, functional water, fluorinated liquid (for example, fluorocarbon) and the like are listed as candidates. The liquid f for immersion is preferably one in which the dissolved gas is sufficiently removed in advance using a deaeration device.
This is because the generation of bubbles is suppressed, and even if bubbles are generated, they can be immediately absorbed into the liquid.
For example, the generation of bubbles can be sufficiently suppressed if 80% or more of the amount of gas that can be dissolved in the liquid is removed, targeting nitrogen and oxygen contained in a large amount in the environmental gas.
Of course, a degassing device (not shown) may be provided in the exposure apparatus, and the liquid f may be supplied to the liquid supply device 7 while always removing the dissolved gas in the liquid.
As the degassing device, for example, a vacuum degassing device in which a liquid is allowed to flow on one side across a gas permeable membrane and the other is evacuated to drive out dissolved gas in the liquid to the vacuum through the membrane is suitable. It is.

Next, an exposure apparatus having the liquid recovery apparatuses 20 and 21 according to the first to fourth embodiments of the present invention will be described with reference to FIGS. 1 to 4 and FIG.
The device protection function using the control valve 29 in the liquid supply device 7 will be described from information from the flow rate sensor 26 configured in the liquid recovery devices 20 and 21.
The liquid immersion control device 19 operates the control valve 29 on the basis of information from the flow sensor 30 included in the liquid supply device 7, thereby allowing the projection optical system 4 and the wafer from the liquid supply nozzle 5 via the supply pipe 16. The flow rate of the liquid f supplied between the stages 10 is controlled.
In the vicinity of the liquid supply nozzle 5, it is transferred from the liquid recovery nozzle 6 for recovering the liquid to the liquid recovery device 20 via the recovery pipe 17 together with the liquid f in a gas-liquid mixed state with the gas g in the atmosphere.
After separating the liquid and the gas inside the liquid recovery apparatus 20, the flow rate of the liquid is measured by the flow rate sensor 26.
Similarly, the liquid f and the gas g are also transferred from the liquid recovery port 31 for recovering a part of the liquid to the wafer stage 10 through the recovery pipe 18 to the liquid recovery device 21, and the flow rate of the liquid is detected by the flow sensor 26. Measure.
The information of the flow sensor 26 is compared with the supply flow rate by the liquid immersion control device 19, and the supply of the liquid is stopped by the control valve 29 when the recovered flow rate is significantly smaller than the supply flow rate.
Although the control valve 29 is used as means for stopping the supply of the liquid, the supply of the liquid to the liquid supply nozzle 5 may be shut off by using an ON / OFF valve (not shown) or a three-way valve.
Moreover, the liquid recovery apparatuses 20 and 21 may be one, or two or more.
In addition to stopping the liquid supply by the control valve 29, it is also effective to stop the wafer stage 10 on the spot in order to minimize the amount of liquid spilled from the wafer stage 10.
It is also effective to move the wafer stage so that the center of the wafer stage 10 is positioned below the projection optical system 4 or to move to the vicinity of the liquid recovery port 31 where the remaining liquid f can be easily recovered. Is.
Thereafter, it is also effective to stop all or part of the power supply to the wafer stage 10 in order to avoid leakage.

Next, with reference to FIGS. 7 and 8, the detection of the flow rate by the liquid recovery apparatus in the immersion exposure apparatus of the present embodiment will be described.
FIG. 7 shows information on the two flow sensors 26 when the liquid f starts to flow between the projection optical system 4 and the wafer stage 10 using the supply and recovery device of the liquid f as shown in FIG. The total (flow rate) is shown in time series.
In the exposure apparatus of FIG. 6, the liquid recovery apparatuses 20 and 21 have a vacuum line 28 shown in FIGS. 1 to 4, and the vacuum suction of the vacuum line 28 can be turned ON / OFF.
The vacuum line 28 is turned on, and the recovery of the liquid f and the gas g from the liquid recovery nozzle and the liquid recovery port is started by a liquid supply command (step 101). (Step 102)
At the start of collection in FIG. 7, the information from the flow sensor 26 is zero. Thereafter, the liquid f and gas g remaining in the recovery pipes 17 and 18 move to the liquid receiver 23.
At this time, the supply of the liquid f from the liquid supply device 7 is stopped.
Therefore, the total amount of the liquid f remaining in the pipes of the recovery pipes 17 and 18 decreases with time, and the moving speed of the liquid f flowing into the liquid receiver 23 increases due to the drop in the pipe pressure loss during transfer. Increase temporarily.
Thereafter, the flow rate detected by the flow rate sensor 26 decreases as the liquid in the recovery pipes 17 and 18 decreases. Next, supply of the liquid f from the liquid supply device 7 via the supply pipe 16 is started. (Step 103)
The liquid f supplied between the projection optical system 4 and the wafer stage 10 is transferred from the liquid recovery nozzle 6 and the liquid recovery port 31 to the liquid recovery devices 20 and 21.
During this time, since the transfer of the liquid f is delayed, it takes a predetermined time for the value of the flow sensor 26 to start increasing again after the liquid supply device 7 starts supplying the liquid f. (Step 104)
During that time, if the tolerance of the flow rate of the collected liquid f is determined, it is erroneously detected as an abnormality, so a predetermined waiting time is used before the tolerance determination is started.
In addition, it is not necessary to carry out the liquid draining operation of the recovery pipes 17 and 18 performed first. In that case, it is possible to shorten the time until the tolerance determination is started. (Step 106)
Thereafter, the supply of the liquid f is stopped. (Step 107)

Next, the liquid recovery apparatuses 20 and 21 according to the first embodiment of the present invention will be described with reference to FIG.
The first embodiment is a liquid recovery apparatus that measures the flow rate of only the liquid in a line in which the gas g and the liquid f are mixed and recovered.
The liquid recovery apparatuses 20 and 21 have recovery pipes 17 and 18 that are one or more recovery lines in which the gas g and the liquid f are mixed and recovered. The decompression tank 22 is a container to which the recovery pipes 17 and 18 are connected and the inside is decompressed. The liquid receiver 23 is provided inside the decompression tank 22 and receives the liquid f discharged from the recovery line.
A pipe 24, which is a drainage line, is connected to the bottom of the liquid receiver 23 and discharges the liquid f into the decompression tank 22 from the outlet 27.
The flow rate sensor 26 that is a flow rate detection unit is provided in the middle of the pipe 24 that is a drainage line, and measures the flow rate of the liquid f.
Furthermore, in the first embodiment, at least a part of a portion of the pipe 24 that is a drainage line that is downstream of the flow rate sensor 26 that is the flow rate detection unit is disposed above the flow rate sensor 26 that is the flow rate detection unit. .
The flow rate sensor 26 which is a flow rate detection unit is provided inside the decompression tank 22 and is a capacity type flow rate sensor.

The collection pipe 17 that collects and collects the gas g and the liquid f is introduced into the decompression tank 22.
The gas g is exhausted by a vacuum line 28 that suctions the gas g in the decompression tank 22 under reduced pressure.
The transferred liquid f and gas g are collected at the bottom of the liquid receiver 23 by the liquid receiver 23 arranged so as to cover the end of the recovery pipe 17, and the gas g is opened in the decompression tank 22. And exhausted through the vacuum line 28.
The liquid f collected at the bottom of the liquid receiver 23 passes through the flow sensor 26 via the pipe 24 connected to the bottom of the liquid receiver 23, and is pushed out from the drain port 27 into the decompression tank 22 via the pipe 25. It is.
By setting the drain outlet 27 at a position higher in the gravity direction 100 than the flow sensor 26, the pipe and the flow sensor at a position lower in the gravity direction 100 than the drain outlet 27 are filled with the liquid f.
When the liquid f transferred through the recovery pipe 17 accumulates at the bottom of the liquid receiver 23 and the water surface becomes higher than the drain outlet 27, the liquid f is transferred toward the drain outlet 27 by the action of the mass of the liquid and gravity. .
By reading the movement of the liquid f with the flow sensor 26, the flow rate of the collected liquid is measured accurately and quickly.
For this reason, the flow rate of the liquid f recovered by mixing the gas and the liquid is measured quickly and accurately, the influence of leakage or intrusion of the liquid f is reduced, and a good exposure process is possible.
Since the liquid level at the bottom of the liquid receiver 23 rises by the pressure loss generated when the liquid flows through the pipes 24 and 25 and the flow sensor 26, the end of the recovery pipe 17 is positioned higher than the drain port 27. And
The liquid f drained from the drain port 27 is stored at the bottom of the decompression tank 22 and is discharged through the drain line 8.

Next, with reference to FIG. 2, the liquid collection | recovery apparatuses 20 and 21 of Example 2 of this invention are demonstrated.
The difference from the embodiment of FIG. 1 is that the arrangement of the pipe 25 from the flow sensor 26 to the drain port 27 is different.
By disposing a part of the pipe 25 at a position higher than the flow rate sensor 26 with respect to the gravity direction 100, the position of the drain port 27 may be arranged at a position lower than the flow rate sensor 26.
However, the highest position of the pipe 25 must be lower than the end of the recovery pipe 17.

Next, with reference to FIG. 3, the liquid recovery apparatuses 20 and 21 according to the third embodiment of the present invention will be described.
A flow rate sensor 26 as a flow rate detection unit is provided outside the decompression tank 22. A pipe 24 connected to the bottom of the liquid receiver 23 is pulled out of the decompression tank 22, passed through the flow meter 26, and again led into the decompression tank 22 by the pipe 25, and then a drain port 27 is provided inside the decompression tank 22. Provide.
By disposing the flow sensor outside the decompression tank 22, the flow sensor is not required to be waterproof, and a highly versatile flow sensor corresponding to negative pressure can be used.

Next, with reference to FIG. 4, the liquid collection | recovery apparatuses 20 and 21 of Example 4 of this invention are demonstrated.
The fourth embodiment is a case where the two collection tubes 17, 17a or 18, 18a are received by the liquid receiver 23, and the number of collection tubes may be two or more.
Here, as in the embodiment of FIG. 3, the flow sensor 26 may be disposed outside the decompression tank 22, or the piping may be changed as in the embodiment of FIG.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described with reference to FIGS.
FIG. 9 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, and the like). Here, a semiconductor chip manufacturing method will be described as an example.
The method comprises the steps of exposing a wafer using an exposure apparatus and developing the wafer, and specifically comprises the following steps.
In step 1 (circuit design), a semiconductor device circuit is designed.
In step 2 (mask production), a mask is produced based on the designed circuit pattern.
In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon.
Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer using the mask and the wafer by the above exposure apparatus using the lithography technique.
Step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and an assembly process such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), or the like. including.
In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test.
Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 10 is a detailed flowchart of the wafer process in Step 4.
In step 11 (oxidation), the surface of the wafer is oxidized.
In step 12 (CVD), an insulating film is formed on the surface of the wafer.
In step 13 (electrode formation), an electrode is formed on the wafer.
In step 14 (ion implantation), ions are implanted into the wafer.
In step 15 (resist process), a photosensitive agent is applied to the wafer.
Step 16 (exposure) uses the exposure apparatus to expose a circuit pattern on the mask onto the wafer.
In step 17 (development), the exposed wafer is developed.
In step 18 (etching), portions other than the developed resist image are removed.
In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed.
By repeatedly performing these steps, multiple circuit patterns are formed on the wafer.

It is a block diagram of the liquid collection | recovery apparatus of Example 1 of this invention. It is a block diagram of the liquid collection | recovery apparatus of Example 2 of this invention. It is a block diagram of the liquid recovery apparatus of Example 3 of this invention. It is a block diagram of the liquid collection | recovery apparatus of Example 4 of this invention. It is a schematic block diagram of the exposure apparatus of the Example of this invention. FIG. 5 is a schematic diagram of a liquid supply / stop mechanism and a control unit of the exposure apparatus of the embodiment of the present invention. It is the figure which showed the flow measurement result by the Example of this invention with the time-axis. It is a flowchart of the Example of this invention. It is a flowchart for demonstrating manufacture of the device using an exposure apparatus. 10 is a detailed flowchart of the wafer process in Step 4 of the flowchart shown in FIG. 9.

Explanation of symbols

1: reticle 2: illumination optical system 3: reticle stage 4: projection optical system 5: liquid supply nozzle 6: liquid recovery nozzle 7: liquid supply device 8: drainage line 9: wafer 10: wafer stage 11: reference mirror 12: measurement Distance laser interferometer 13: stage controller,
14, 15: Surface plate 16: Supply pipe 17, 17a: Recovery pipe 18: Recovery pipe 19: Immersion control apparatus 20, 21: Liquid recovery apparatus 22: Depressurization tank 23: Liquid receiver 24: Pipe 1
25: Piping 2
26: Flow sensor 27: Drain port 28: Vacuum line 29: Control valve 30: Flow sensor 31: Liquid recovery port f: Liquid for immersion g: Gas 100: Direction of gravity

Claims (12)

One or more recovery lines in which gas and liquid are mixed and recovered;
A decompression tank to which the recovery line is connected and the inside is decompressed;
A liquid receiver provided inside the vacuum tank and receiving the liquid discharged from the recovery line;
A drain line connected to the bottom of the liquid receiver and for discharging the liquid into the vacuum tank;
A flow rate detector provided in the middle of the drainage line and measuring the flow rate of the liquid,
A liquid recovery apparatus, wherein at least a part of a portion of the drainage line downstream of the flow rate detection unit is disposed above the flow rate detection unit.   The liquid recovery apparatus according to claim 1, wherein the flow rate detection unit is provided inside the decompression tank.   The liquid recovery apparatus according to claim 1, wherein the flow rate detection unit is provided outside the decompression tank.   The liquid recovery apparatus according to claim 1, wherein the flow rate detection unit is a capacitive flow rate sensor. An exposure apparatus that exposes the substrate via a liquid supplied between the final lens of the projection optical system closest to the substrate and the substrate,
A supply line for supplying the liquid under the final lens;
A valve provided in the middle of the supply line to control the flow of the liquid;
A control unit for controlling opening and closing of the valve;
An exposure apparatus comprising: the liquid recovery apparatus according to claim 1.   5. A comparator for comparing information from the flow rate detection unit of the liquid recovery apparatus according to claim 1 with a flow rate of the liquid supplied under the final lens. Item 6. The exposure apparatus according to Item 5. The comparator has a tolerance for determining an abnormality,
The control unit controls the valve to stop liquid supply under the final lens when information from the flow rate detection unit is out of the tolerance range. Exposure equipment.   An exposure apparatus according to any one of claims 5 to 7, comprising a plurality of liquid recovery apparatuses according to any one of claims 1 to 4.   The exposure apparatus according to claim 8, wherein each of the liquid recovery apparatuses according to claim 1 includes the flow rate detection unit.   6. The comparator according to claim 5, wherein the tolerance is determined based on any one, a plurality, or all of the information of the one or more flow rate detection units. The exposure apparatus according to any one of 9.   11. The exposure apparatus according to claim 5, wherein the tolerance determination by the comparator does not determine the tolerance during a predetermined time after the liquid supply is started. A step of exposing the wafer using the exposure apparatus according to claim 5;
And a step of developing the exposed wafer.

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