JP2006041251A - Exposure system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently remove moisture of a filter and to reduce an inert gas circulation rising time. <P>SOLUTION: The exposure system has a chamber 3 which isolates at least a part of the system body, a blower 10 for circulating an inert gas to the chamber, and a filter 11 for purifying the inert gas. The exposure system is further provided with a filter drying means 25 for creating a dry gas, for circulating the dry gas via the filter not through the chamber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus having an inert gas temperature control circulation system.

The light source of an exposure apparatus used for semiconductor manufacturing or the like has become shorter in wavelength with the finer exposure pattern. That is, the exposure light source has shifted from i-line to excimer laser, and the laser light source has also shifted from KrF to ArF. Currently, the use of an F ₂ laser is being studied in order to satisfy the demand for further miniaturization.

In order to construct an exposure system using an F ₂ laser as a light source, it is necessary to take measures against exposure light energy attenuation. Since the energy of F ₂ laser light is absorbed by moisture, oxygen, organic gas, etc. contained in the atmosphere, a conventional exposure apparatus cannot be applied as it is.

Therefore, as a means for dealing with the F ₂ laser, a method is conceivable in which the entire space through which the exposure light passes is sealed with a partition wall and the space is filled with an inert gas such as nitrogen. However, even in this method, the space in which the wafer and the reticle are arranged generates a large amount of heat generated by the linear motor of the stage, etc., and in order to maintain the positional accuracy, the temperature control circulation of the inert gas for the purpose of removing the temperature fluctuation in the space Requires a system.

  FIG. 3 shows a schematic diagram of a conventional inert gas circulation system. The wafer space 1 and the reticle space 2 inside the exposure apparatus main body are surrounded by a chamber 3, and the inside of the chamber 3 is a sealed space. Each space is provided with a temperature control gas blowing section 4 and a recovery section 5.

  In order to circulate the temperature-controlled and contaminated inert gas in the chamber 3, a circulation device 6 is installed and connected to the blow-out part 4 and the recovery part 5 of the chamber 3 via a supply duct 7 and a return duct 8, respectively. Is done. The circulation device 6 includes internal devices arranged in the order of the cooler 9, the blower 10, the filter 11, and the heater 12 in the flow direction of the inert gas.

  The inert gas recovered from the interior of the wafer space 1 and the reticle space 2 via the return duct 8 absorbs heat generated in the wafer space 1 and the reticle space 2, so that heat is exchanged with the refrigerant in the cooler 9. The The cooled inert gas is sent to the filter 11 to remove contamination. Here, the filter 11 includes a chemical filter that removes ammonia rich in resist reactivity, an activated carbon filter that removes siloxane and other organic gases that degrade the optical member, a ULPA filter that removes particles, and the like. The inert gas that has been cooled and removed of contaminants is further heated and regulated by the heater 12 and circulated to the temperature regulating gas blowing section 4. The power source of the circulating fluid transfer is the blower 10.

  At the same time, an inert gas having a high purity is injected into the wafer space 1 and the reticle space 2 from the inert gas injection valve 13, thereby maintaining the concentration of the inert gas in the wafer space 1 and the reticle space 2. By discharging a predetermined amount of gas through the throttle valve 15 from 14, the internal pressures of the wafer space 1 and the reticle space 2 are increased to prevent the outside air from entering.

The temperature control of the inert gas is performed by the temperature sensor 16 detecting the temperature of the inert gas, the signal being input to the temperature controller 17, and the output of the heater 12 being adjusted by PID feedback control.
JP 09-246140 A

By the way, the conventional inert gas circulation system has a filter for the purpose of removing contamination of the inert gas, but the actual surface area of the filter is very large and adsorbs a large amount of moisture. In particular, when the filter is exposed to the atmosphere during initial start-up or maintenance or the like, a large amount of water is contained, so that it takes a long time to reduce the water to a predetermined concentration or less.
Therefore, the time for lowering the moisture concentration can be shortened by heating with a heater in order to dry the moisture in the filter, but it is not preferable to heat and circulate as it is in the normal circulation path because the exposure apparatus main body is also heated. In addition, it is conceivable that only the filter part is sealed without circulating, and the inside is charged and discharged with inert gas, and the inside is heated at the same time. However, natural convection is dominant and temperature unevenness occurs, making uniform heating difficult. In addition, since there is little movement of the fluid, it becomes saturated immediately and sufficient drying cannot be performed. Moreover, if a long time is required for cooling and normal circulation is started in a state where the cooling is insufficient, the internal pressure rises due to the closed system, and there is a risk of destroying a device sensitive to pressure such as a lens.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to efficiently remove moisture from the filter and shorten the startup time of the inert gas circulation.

  In order to achieve the above object, in the present invention, exposure includes a chamber that isolates at least a part of an exposure apparatus body, a blower that circulates an inert gas in the chamber, and a filter that cleans the inert gas. In the apparatus, there is provided a filter drying unit that generates dry gas and circulates the dry gas through the filter without passing through the chamber.

  According to the present invention, it is possible to shorten the time required for filter drying by generating dry gas having a high water absorption capacity, and to reduce the consumption of inert gas by reusing dry gas by circulation. be able to.

In a preferred embodiment of the present invention, an air-tight chamber, a blower that circulates an inert gas in the air-tight chamber, a cooler that cools the inert gas, a heater that heats the inert gas, and contamination removal of the inert gas are performed. An exposure apparatus having an inert gas circulation system comprising a filter, and a temperature control and cleaning function inside the hermetic chamber by means of a sensor and a temperature controller installed at predetermined positions of the circulation system, including a blower, a cooling device It has a filter dry function having a dry gas generating function composed of a heater and a heater, and a circulation path for circulating the generated dry gas through the filter.
According to the above configuration, the time required for filter drying can be shortened by generating dry gas having a high water absorption capacity, and the consumption of inert gas can be reduced because the dry gas is reused by circulation. be able to.

  Here, the dry gas is preferably the same or the same kind as the inert gas. This eliminates the need for purge of dry gas at the end of filter drying. Moreover, it is preferable that this filter dry function has a temperature sensor and temperature controller which detect the temperature of a filter part, and can temperature-control a filter part. As a result, the cooling waiting time at the end of the filter drying can be shortened, and in addition to shortening the time required for the filter drying, the overall start-up time can be shortened, resulting in an improvement in throughput.

In addition, it is preferable that a drain discharge port is provided in the cooler part of the filter drying function so that the moisture absorbed by the filter part can be discharged to the outside. The filter dry function preferably has an inert gas supply port and an inert gas discharge port, and can maintain the concentration of the inert gas inside by injecting a high purity inert gas. Further, it is preferable that the inert gas outlet is also used as the drain outlet.
In addition, on the path of the inert gas circulation system, upstream of the filter and upstream of the connection port of the dry gas circulation path, downstream of the filter and downstream of the connection port of the dry gas circulation path. It is preferable to prevent the dry gas from reaching the exposure apparatus main body by newly providing a valve for blocking the inert gas circulation path. Providing a valve that shuts off the inert gas circulation path also has the effect of reducing the return and startup time without contacting the filter with the atmosphere even during maintenance in the chamber.

  The filter drying function can also be realized by using a blower, a cooler, and a heater constituting the inert gas circulation system. For example, a bypass path that bypasses the chamber is newly provided, and shut-off valves are provided in the bypass path and each inlet and outlet of the chamber, thereby switching between the chamber and the bypass. Further, a supply valve for supplying an inert gas to the circulation system, and a discharge valve for discharging the inert gas to the circulation system, the discharge valve is provided in the cooler section, and the condensed water generated in the cooler is discharged. It is preferable that at least one supply valve is provided in the circulation system other than the chamber and the bypass path. Accordingly, the dry gas can be generated and circulated by the inert gas circulation system equipment originally provided in the exposure apparatus, and the filter dry function can also be used.

Hereinafter, the present invention will be described in more detail based on examples.
[First embodiment]
FIG. 1 is a conceptual view of an exposure apparatus according to the first embodiment of the present invention. The exposure apparatus shown in FIG. 6 is provided with a dry gas generation device 25 in contrast to the conventional example shown in FIG. Connected.
That is, in the exposure apparatus of FIG. 1, the wafer space 1 and the reticle space 2 inside the exposure apparatus main body are surrounded by the chamber 3, and the inside of the chamber 3 is a sealed space. Each space is provided with a temperature control gas blowing section 4 and a recovery section 5. In order to circulate the temperature-controlled and contaminated inert gas in the chamber 3, a circulation device 6 is installed and connected to the blow-out part 4 and the recovery part 5 of the chamber 3 via a supply duct 7 and a return duct 8, respectively. Is done. The circulation device 6 includes internal devices arranged in the order of the cooler 9, the blower 10, the filter 11, and the heater 12 in the flow direction of the inert gas.

  A dry gas exhaust port 21 and a dry gas supply port 22 are newly provided upstream and downstream of the filter 11 provided inside the inert gas circulation device 6. Further, an exhaust duct 23 and an air supply duct 24 are provided at the dry gas exhaust port 21 and the dry gas supply port 22, respectively, and are connected to the dry gas generation device 25. As a result, a dry gas circulation path that circulates between the filter 11 and the dry gas generator 25 is formed. In order to prevent a path bypassing the filter 11 during normal inert gas circulation, at least one shutoff valve 26 is provided on the dry gas circulation path.

  Also on the path of the inert gas circulation system, a shutoff valve 27 is provided upstream of the filter 11 and upstream of the dry gas exhaust port 21, and further downstream of the filter 11 and the dry gas supply port 2. A shut-off valve 28 is provided on the downstream side of the valve, and the shut-off valve 27 and the shut-off valve 28 are opened during normal inert gas circulation. The circulation path is closed to prevent the hot dry gas from entering the main body.

The dry gas generator 25 includes internal devices arranged in the order of a dry gas cooler 29, a dry gas blower 30, and a dry gas heater 31 in the flow direction. Further, a drain discharge valve 32 is provided in the dry gas cooler 29 portion.
The dry gas generating device 25 further has an inert gas supply port 33 and an inert gas discharge port 34, and has a structure in which an inert gas can be injected and discharged.
Furthermore, it has a temperature sensor 35 for detecting the temperature of the filter 11 part and a temperature controller 36 for adjusting the output to the dry gas heater 31 according to the detected temperature, so that the temperature of the filter part can be adjusted.

A filter drying method in this embodiment will be described.
When performing filter drying, the shut-off valve 27 and the shut-off valve 28 are closed to shut off the inert gas circulation path and the shut-off valve 26 is also closed, and high-purity inert gas is supplied from the inert gas supply port 33. The gas is discharged from the inert gas outlet 34 and the closed space is replaced with the inert gas. After the inert gas replacement, the shutoff valve 26 is opened to open the dry gas circulation path. The dry gas blower 30 is driven and circulated while purging the inert gas from the inert gas supply port 33.

The circulating gas is cooled by the dry gas cooler 29 and is dehydrated by dehydrating the supersaturated water at the cooling temperature of the circulating gas, and is supplied to the dry gas heater 31. The dry gas whose temperature is adjusted by the dry gas heater 31 becomes a dry gas having a higher moisture absorption capacity and is supplied to the filter unit.
At this time, the temperature sensor 36 controls the output of the dry gas heater 31 so that the temperature of the filter unit becomes a predetermined temperature. The set temperature is preferably about 110 ° C. in terms of dry performance, but when the upper limit of heat resistance of the filter 11 is 110 ° C. or less, the heat resistant temperature is set.

When the dry gas passes through the filter 11, the dry gas absorbs a maximum amount of moisture contained in the filter 11 until reaching the saturation state of the heating temperature of the dry gas heater 31, and is circulated to the dry gas cooler 29. .
Water in the filter is condensed by the dry gas cooler 29 and discharged from the drain discharge valve 32.
Here, it is more preferable that the drain discharge valve 32 and the inert gas discharge port 34 are combined.

  In this embodiment, the flow direction of the air flow during the circulation of the inert gas is opposite to the flow direction of the dry gas during the filter drying, but the present invention does not limit the flow direction. Therefore, the present invention includes the case where the flow direction of the air flow during the circulation of the inert gas is the same as the flow direction of the dry gas during the filter drying.

  According to this embodiment, it is possible to reduce the time required for filter drying by generating dry gas having a high water absorption capacity, and to recycle dry gas by circulation, thereby reducing the consumption of inert gas. Can be reduced.

Further, when the filter drying is finished, the dry gas circulation system can be quickly cooled by the dry gas cooler 29 by turning off the dry gas heater 31, and the cooling waiting time can be shortened.
Also, when switching from filter drying to normal inert gas circulation, the dry gas circulation system is temperature-controlled circulation at the same temperature setting as the inert gas circulation state, and then the shutoff valve 26 is closed to circulate the dry gas. By stopping, the pressure fluctuation due to the temperature difference when the shut-off valve 27 and the shut-off valve 28 are opened can be reduced.
Further, during maintenance in the chamber, by closing the shut-off valve 27 and the shut-off valve 28, maintenance can be performed without bringing the filter into contact with the atmosphere, and moisture absorption of the filter can be reduced. In addition, the return or startup time of the inert gas circulation can be shortened.

[Second Embodiment]
FIG. 2 is a conceptual view of an exposure apparatus according to the second embodiment of the present invention. Parts common to the above-described conventional example shown in FIG. 3 and the first embodiment shown in FIG. 1 are denoted by the same reference numerals. The apparatus of FIG. 2 has the same function as that of the first embodiment, but the dry gas is generated and circulated using the inert gas circulator 6 without using a dedicated generator. Different from the first embodiment. Note that the order of the filter 11 and the heater 12 is changed from that of the first embodiment so that the heated gas is directly supplied to the filter 11.

As shown in FIG. 2, the wafer space 1 and the reticle space 2 inside the exposure apparatus main body are surrounded by a chamber 3, and the inside of the chamber 3 is a sealed space. Each space is provided with a temperature control gas blowing section 4 and a recovery section 5. In order to circulate the temperature-controlled and contaminated inert gas in the chamber 3, a circulation device 6 is installed, to the blow-out unit 4 through the supply duct 7, and to the recovery unit 5 through the return duct 8. Connected.
The circulation device 6 includes internal devices arranged in the order of the cooler 9, the blower 10, the heater 12, and the filter 11 in the flow direction of the inert gas.

  A bypass path 37 for newly connecting the supply duct 7 and the return duct 8 to bypass the chamber 3 is newly provided, and a bypass path cutoff valve 38 for blocking the bypass path 37 is provided on the bypass path 37. Further, a chamber path shut-off valve 39 that shuts off the circulation path to the chamber 3 is provided between the chamber 3 and the junction between the bypass path 37 and the supply duct 7 and the return duct 8.

  The circulation device 6 is provided with a drain discharge port 32 in the cooler 9 part which is an internal device, and further has an inert gas supply port 33 and an inert gas discharge port 34 to inject and discharge the inert gas. A structure that can be used. Furthermore, it has the temperature sensor 35 which detects the temperature of a filter part, and sets it as the structure which can temperature-control a filter part.

A filter drying method in this embodiment will be described.
When performing filter drying, the chamber path shut-off valve 39 is closed and the bypass path shut-off valve 38 is opened so that the circulation path to the chamber 3 is shut off and the bypass path 37 is opened. In this state, high-purity inert gas is injected from the inert gas supply port 33 and discharged from the inert gas discharge port 34, and the closed space formed by the bypass path 37 and the circulation device is replaced (purged) with the inert gas. To do. After the inert gas replacement, the blower 10 is driven and circulated while purging the inert gas from the inert gas supply port 33.

The circulating gas is cooled by the cooler 9 and dehydrated by the supersaturated water at the cooling temperature of the circulating gas, thereby becoming dry gas and supplied to the heater 12. The dry gas whose temperature is superheated by the heater 12 becomes a dry gas having a higher moisture absorption capacity and is supplied to the filter unit. At this time, the temperature controller 17 controls the output of the heater 12 so that the temperature of the filter unit becomes a predetermined temperature. Here, the temperature controller 17 has inputs for two temperature sensors, and can input a signal from the temperature sensor 16 during normal inert gas circulation and a signal from the temperature sensor 35 during filter drying. A structure having a switching function and a function capable of setting different temperatures when the inert gas is circulated and when the filter is dried is used.
The set temperature at the time of filter drying is preferably about 110 ° C. in view of the dry performance.

  When the dry gas passes through the filter 11, the dry gas absorbs the amount of moisture contained in the filter 11 up to the saturation state of the heating temperature of the heater 12 and is circulated to the cooler 9. Water in the filter is condensed by the dry gas cooler 29 and discharged from the drain outlet 12. Here, it is more preferable that the drain discharge port 12 and the inert gas discharge port 34 are combined.

When the filter is dry, the chamber path shut-off valve 39 is closed as described above, so that high-temperature dry gas does not flow into the exposure apparatus main body and the chamber 3. In consideration of further thermal effects, it is preferable that the installation positions of the bypass path 37 and the chamber path shut-off valve 39 be as far as possible from the exposure apparatus main body and the chamber 3.
Moreover, it is preferable that the air blower 10 in the circulation device 6 is provided with an air volume adjustment function (not shown) such as an inverter so that an optimum air volume can be set for each of normal inert gas circulation and filter drying.

  According to the present embodiment, the same function as that of the first embodiment can be realized by combining the devices used during the normal inert gas circulation, so that there are further advantages such as space saving and cost reduction of the apparatus. Added.

[Third embodiment]
Next, a semiconductor device manufacturing process using this exposure apparatus will be described.
FIG. 4 shows a flow of manufacturing a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.).
In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask production), a mask on which the designed pattern is formed is produced.
On the other hand, 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 by lithography using the wafer and the exposure apparatus provided with the prepared mask. The next step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and is an assembly process (dicing, bonding), packaging process (chip encapsulation), etc. Process. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. A semiconductor device is completed through these processes, and is shipped in Step 7.

  The wafer process in step 4 includes the following steps. An oxidation step for oxidizing the surface of the wafer, a CVD step for forming an insulating film on the wafer surface, an electrode formation step for forming electrodes on the wafer by vapor deposition, an ion implantation step for implanting ions on the wafer, and applying a photosensitive agent to the wafer The resist processing step, the exposure step for printing and exposing the circuit pattern onto the wafer after the resist processing step by the above-described exposure apparatus, the development step for developing the wafer exposed in the exposure step, and the etching for removing portions other than the resist image developed in the development step Step, resist stripping step to remove resist that is no longer needed after etching. By repeating these steps, multiple circuit patterns are formed on the wafer.

1 is a schematic view of an exposure apparatus according to a first embodiment of the present invention. It is the schematic of the exposure apparatus which concerns on the 2nd Example of this invention. It is explanatory drawing of a prior art. It is a figure explaining the flow of the manufacturing process of a device.

Explanation of symbols

1: Wafer Space 2: Reticle Space 3: Chamber 4: Temperature Control Gas Blowout Unit 5: Recovery Unit 6: Circulation Device 7: Supply Duct 8: Return Duct 9: Cooler 10: Blower 11: Filter 12: Heater 13: Inert gas injection valve 14: Discharge valve 15: Throttle valve 16: Temperature sensor 17: Temperature controller 21: Dry gas exhaust port 22: Dry gas supply port 23: Exhaust duct 24: Supply duct 25: Dry gas generator 26 : Shut-off valve 27: Shut-off valve 28: Shut-off valve 29: Dry gas cooler 30: Dry gas blower 31: Dry gas heater 32: Drain discharge valve 33: Inert gas supply port 34: Inert gas discharge port 35: Temperature Sensor 36: Temperature controller 37: Bypass path 38: Bypass path shut-off valve 39: Chamber path shut-off valve

Claims (9)

In an exposure apparatus having a chamber that isolates at least a part of an exposure apparatus main body, a blower that circulates an inert gas in the chamber, and a filter that cleans the inert gas.
An exposure apparatus comprising: a filter drying unit that generates dry gas and circulates the dry gas through the filter without passing through the chamber.   The filter drying means includes a blower that circulates the dry gas through the filter, a cooler that cools the gas that has passed through the filter, and a heater that heats the cooled gas. Item 2. The exposure apparatus according to Item 1.   3. An exposure apparatus according to claim 2, wherein the inert gas circulation system is also used as at least one of a blower, a cooler and a heater of the filter drying means.   The exposure apparatus according to claim 1, wherein the filter drying unit includes a valve that blocks the inert gas circulation path at an inlet and an outlet of the chamber.   The exposure according to claim 1, wherein the filter drying unit includes a path that bypasses the chamber and a valve that switches a gas circulation path between the chamber side and the bypass path side. apparatus.   The said filter drying means is provided with the temperature sensor which detects the temperature of the said filter part, and the means which temperature-controls the said dry gas based on the output of this temperature sensor, The any one of Claims 1-5 characterized by the above-mentioned. The exposure apparatus according to one.   The exposure apparatus according to claim 1, wherein the dry gas is the inert gas.   The filter drying means has a supply valve that supplies dry gas to a dry gas circulation system, and a discharge valve that discharges gas from the circulation system, and the discharge valve is disposed in the cooler portion, and the discharge valve The exposure apparatus according to claim 1, wherein the condensed water generated in the cooler can be discharged through the exposure apparatus.   A device manufacturing method, comprising: a step of exposing a substrate using the exposure apparatus according to claim 1; and a step of developing the exposed substrate.

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