JP2000021744A - Exposure equipment and manufacture of device using the equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent surface contamination of optical elements due to reactive products caused by exposure light irradiation, driving mechanisms or the like, by placing in the outside space of an optical enclosure a driving source and mechanisms that drive and adjust optical elements accommodated in the optical enclosure, which is located in the optical path of an exposure light for irradiating a photosensitized substrate. SOLUTION: Inside of each block of a routing optics system and of an illumination optics system, and inside of a projection optics system are replaced with nitrogen gas from a nitrogen feed source. A motor is set outside of a zoom cam mirror tube 25, and rotates the zoom cam mirror tube 25 around an optical axis. Here, insides of a lens tube 31 and of the zoom can mirror tube 25 are filled with nitrogen gas, and are separated perfectly from the outside space by an O-ring 27. Gear 28, gear member of the zoom cam mirror tube 25, motor 29 and cables for the motor are placed in the outside space, which is separated from the nitrogen-gas filled space where the optical elements are accommodated. Usually, organic materials such as grease for lubricating gear are used to those parts and their mounting materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an exposure apparatus used for manufacturing semiconductors and the like, and a device manufacturing method using the apparatus.

[0002]

2. Description of the Related Art In recent years, demands for higher density and higher integration of semiconductor integrated circuits have been increasing more and more. Further, in order to improve the productivity of semiconductor devices, a reduction in exposure time is required. For this reason, in lithography technology for processing circuit patterns, in order to miniaturize the pattern and shorten the exposure time, it is necessary to use an exposure apparatus that uses deep ultraviolet light or excimer laser light as a light source to obtain strong illuminance at a short wavelength. Has become commonplace. Irradiation of these lights makes it easier to activate the gas around the optical elements constituting the illumination optical system and the projection optical system, so that the surface of the optical elements is more likely to be contaminated. Therefore, a method has been proposed in which the optical elements of the illumination optical system and the projection optical system are housed in a sealed container or the like, and the inside of the container is filled or replaced with clean dry air or an inert gas to prevent contamination of the internal optical elements. Have been.

[0003]

In the above conventional example, a container (optical container) for housing an optical element is provided with an inlet or the like, through which clean dry air or an inert gas or the like is filled and replaced to thereby provide an optical element. It is intended to prevent the contamination of water. However, if optical elements such as an optical variable stop, a zoom lens, and an optical axis adjustment mirror are configured inside the optical container, and a drive source, a drive transmission mechanism, an adjustment mechanism, and the like for driving and adjusting these are included. There is a possibility that the purity and cleanliness of the filling gas may be reduced due to the influence of impurities and the like generated from the surroundings (motor, bearing, adhesive for forming the driving mechanism, grease, wiring cable, etc.). is there. When the exposure light passes through such an optical container, activation and chemical change of the gas containing impurities occur, which also contaminates the surface of the optical element, thereby reducing the illuminance and unevenness of the illuminance of the exposure light passing through the optical system. There is a problem that causes. Further, dust generated from the driving mechanism, the adjusting mechanism, and the like may become a substance adhering to the surface of the optical component, and similarly, may cause a decrease in illuminance or an uneven illuminance.

When the source of impurities is contained in the optical container, the flow rate of the gas required for replacement depends on the amount of contaminants in order to reduce the influence of the generation of impurities and improve the cleanliness in the container. Must be increased. In addition, if a driving mechanism, an adjusting mechanism, and the like are configured inside the optical container, the volume of the optical container becomes large, and similarly, the flow rate of the replacement gas becomes unnecessarily large. Therefore, there is a disadvantage in running cost for replacing the gas.

Further, when a drive mechanism including a motor and the like, a manual adjustment mechanism, and the like are configured inside the optical container, it is necessary to open the container partially when performing maintenance and adjustment. Therefore, there is a possibility that the working efficiency is adversely affected, and a time for refilling the gas is required even when the apparatus is started.

Accordingly, a first object of the present invention is to provide an optical element surface in an optical container with a reaction product generated by a chemical reaction of an impurity caused by exposure light or dust generated from a driving mechanism and an adjusting mechanism. An object of the present invention is to provide an exposure apparatus and a device manufacturing method capable of preventing contamination.

A second object is to reduce the consumption of inert gas such as clean dry air and nitrogen gas required for replacing the gas in the optical container, to improve the maintainability of the drive mechanism and the like, and to reduce the downtime of the apparatus. An object of the present invention is to provide an exposure apparatus and a device manufacturing method capable of shortening.

[0008]

The above object is achieved by the following objects.
Achieved by arranging a drive source, drive transmission mechanism, and adjustment mechanism for driving and adjusting the optical element in the optical container arranged on the optical path of the exposure light irradiated on the photosensitive substrate in the external space of the optical container Was done.

That is, the exposure apparatus of the present invention illuminates a mask with exposure light from an exposure light source via an illumination optical system,
An exposure apparatus for projecting and exposing a pattern on the mask onto a photosensitive substrate via a projection optical system, wherein the illumination optical system and the projection optical system respectively drive an optical element and a driven element of the optical element. And an optical container housing the optical element and the drive system, wherein at least a part of the drive system is disposed in an external space of the optical container.

Here, the driven element includes an optical element such as a lens and a mirror. In addition, the drive system according to the present invention may include an adjustment mechanism, a wiring, and the like, in addition to the drive source and the drive transmission mechanism, and at least one or a part of them is disposed in the external space of the optical container. Is done.

In the configuration of the present invention, the space including the drive mechanism (motor, bearing, adjustment knob, etc.) and its peripheral portion (wiring cable, etc.) is separated from the space in the container that houses the optical element. Therefore, it is possible to prevent impurities and dust generated from the components constituting the drive mechanism and its peripheral portion and the adhesive used for joining the drive mechanism from entering the optical container, and to prevent the optical mechanism causing the impurities and dust from being generated. Part (element) surface contamination can be prevented.

Further, by disposing the drive mechanism and the like outside the optical container, it is possible to improve the cleanliness inside the optical container and to reduce the volume of the container, and clean dry air required for gas replacement. And the required flow rate of inert gas and the like can be reduced.

Further, since the drive mechanism and the like are disposed outside the container, maintenance of the drive mechanism can be performed without opening the container filled with gas, thereby improving maintenance workability. Can be. Further, gas filling after maintenance becomes unnecessary, and downtime of the apparatus can be reduced.

The optical container used in the present invention may have at least one inlet for introducing gas into the container and one outlet for exhausting gas from the container. In this case, the inlet and the outlet In addition, a closed structure having no opening can be provided. Further, a sealed structure having no opening may be used.

[0015]

EXAMPLES First Embodiment FIG. 1 is a schematic view of an exposure apparatus according to the first to third embodiments. This exposure apparatus includes an exposure light source 1 and a routing optical system 2.
, Illumination optical systems 3 to 6, and reticle 7 as a mask
, A projection optical system 8, a wafer 9 as a photosensitive substrate, and a substrate stage 10 on which the wafer 9 is mounted.
Of these components, the exposure main unit excluding the exposure light source 1 and the routing optical system 2 is housed in a chamber 13 controlled at a constant temperature.

As the exposure light source 1, KrF (wavelength 248n)
m), ArF (wavelength 193nm), F ₂ (157nm)
An excimer laser that emits pulsed light in the ultraviolet region such as the above is used. Note that an i-line (wavelength: 365 nm) of a mercury lamp or the like may be used as an exposure light source instead of an excimer laser.

The routing optical system 2 is an optical system unit that connects the exposure light source 1 and the chamber 13 and includes optical elements such as lenses and mirrors.

The illumination optical system is composed of four blocks 3-6. First, the first block 3 and the fourth block 6 are provided with a folding mirror 2 for folding a light beam of illumination light.
3 and 19 are arranged, and the return mirror 23 has an optical axis adjusting mechanism. The second block 4 includes a beam shaping lens system 14 and a turning mirror 15. The third block 5 includes a zoom lens system 16, a fly-eye lens 17, and a relay lens system 18.

Next, the configuration of each part of the exposure optical system will be described together with its operation. Illumination light emitted from the exposure light source 1 enters the chamber 13 via the routing optical system 2. The drawing optical system 2 enables the exposure light source 1 and the chamber 13 to be installed at appropriate separated positions. The illumination light via the routing optical system 2 is transmitted to the illumination optical system first block 3.
Of the second block 4
The beam is shaped into an optimum beam cross-sectional shape for exposure by passing through the beam shaping lens system 14 of FIG. Next, the illumination light expanded to a required size by the zoom lens system 16 of the third block 5 enters the fly-eye lens 17. The exit side surface of the fly-eye lens 17 has an optically conjugated positional relationship with the light source 1 and forms a secondary light source surface. afterwards,
The illuminating light passes through the relay lens system 18 and the fourth block 6
The reticle 7 is bent by the turning mirror 19 to uniformly illuminate the reticle 7, and the projection optical system 8 (projection lens system 20) projects and exposes the image of the reticle 7 onto the wafer 9 held on the substrate stage 10.

Further, a nitrogen supply source 1 is provided to the routing optical system 2, the blocks 3 to 6 of the illumination optical system, and the projection optical system 8.
Numerals 1 are connected to each other through a pipe 12 to supply nitrogen gas. Accordingly, the drawing optical system 2, the respective blocks 3 to 6 of the illumination optical system, and the projection optical system 8 are controlled by the nitrogen supply source 11.
Is replaced with nitrogen gas. Here, in the first embodiment and the second embodiment described below, the supply gas is nitrogen gas. In any case, the supply gas is not limited to nitrogen gas, but may be an inert gas such as helium or neon, or a clean gas. Dry air, etc., or organic silicon compounds, ammonia,
Any gas that does not contain at least one of sulfate ions and organic gas may be used. The piping to the routing optical system 2, the blocks 3 to 6 of the illumination optical system, and the projection optical system 8 is as follows.
One or more may be used. Alternatively, each block may be a completely closed space that does not require a piping route, or a structure in which gas is supplied from the piping temporarily and then the piping is cocked to form a completely closed space.

FIG. 2 is a plan view (a) and a sectional view (b) of the zoom lens system 16 used in this embodiment.

The lenses 21a and 21b are held by lens holders 22a and 22b, respectively. A lens barrel 31 and a straight cam barrel 24 are arranged outside the lens, and the straight cam barrel 24 holds a zoom cam barrel 25 via a bearing 26. A motor 29 is provided outside the zoom cam barrel 25, and the zoom cam barrel 25 is driven to rotate about the optical axis via a gear 28. The cam groove 24 is provided in the straight cam barrel 24 and the zoom cam barrel 25.
a and 25a are formed, and with the rotation of the zoom cam barrel 25, the lens holder is driven via a cam follower 30 attached to the outer peripheral portion of the lens holders 22a and 22b to form a lens zoom mechanism.

Here, the inside of the lens barrel 31 and the zoom cam barrel 25 is a space filled with nitrogen gas.
7 completely separates the external space. The cam groove 25a of the zoom cam barrel 25 is formed only on the inner peripheral surface so as not to penetrate outside.

In this configuration, the gear 28, the gear portion of the zoom cam barrel 25, the motor 29 and the motor cable (not shown) are arranged in an external space separated from the nitrogen gas filled space including the optical element. Normally, these components and their assembly materials include grease for gear lubrication, adhesive for motor coil formation, coating of wiring cables, and other substances that are formed of organic substances and easily release gases that cause lens contamination. Many included. Further, there is a possibility that dust may be generated from the meshing portion of the gear. However, with the configuration shown in this embodiment, the nitrogen gas filled space including the optical element is not contaminated by the influence of these substances.

The O-ring 27 for shielding the space filled with nitrogen gas from the outer space is made of chemically stable ethylene tetrafluoride or the like, and is provided with a stainless steel spring from the inside so as to obtain an appropriate surface pressure. A lubrication method using no lubrication or low-volatility vacuum grease is used. It is desirable that the rollers used for the bearing 26 and the follower 30 of the cam be of a non-lubricated type.

With the configuration described above, it is possible to prevent impurities and dust from entering the interior space of the lens barrel filled with nitrogen gas, and to prevent contamination of the optical element disposed inside the barrel.

Further, by disposing the actuator and the driving mechanism outside the gas filling space, the substantial gas filling space volume substantially coincides with the volume inside the lens barrel. Therefore, the gas filling space volume can be minimized, and the required consumption flow rate at the time of gas filling can be reduced and the filling speed can be improved. Further, by arranging the actuator outside, it becomes possible to open the gas filling area and perform the work without polluting the inside of the space when maintenance of the actuator is required.

Also, an optically variable stop (not shown) disposed near the pupil of the illumination optical system or the projection optical system is disposed around the light beam and requires external driving. Also in this case, similarly to the structure described in the above embodiment, the actuator and the drive transmission mechanism are arranged in the outer space of the lens barrel, and are separated from the inner space of the lens barrel filled with nitrogen gas or the like. Can be. Similarly, in this case, it is necessary to prevent contamination of the optical element disposed inside the lens barrel,
The maintainability can be improved.

Second Embodiment FIG. 3 shows a first block 3 of the illumination optical system used in this embodiment.
FIG. The space inside the mirror box 36 and the light shielding tube 32 is filled with nitrogen gas, and the box 36 has a folding mirror 23 for folding a light beam therein. The folding mirror 23 is held by a mirror holder 33, and has a mechanism capable of adjusting an optical axis by rotation about a rotation axis O. To perform this rotation adjustment, an adjustment screw 34 is provided from outside the mirror box 36.

Here, the adjusting screw 34 and the mirror box 3
Since each of the screws 6 is threaded, there is a small gap in the engagement portion, which cannot be ignored for gas leakage from the inside of the box 36 or contamination from the outside. Further, at the time of adjustment, dust may be generated due to friction of the screw portion or the tip of the adjustment screw 34.

Therefore, an extendable bellows tube 35 is arranged around the adjusting screw 34, and both end surfaces of the tube 35 are connected to the mirror holder 33 and the mirror box 36. Use a bellows tube made of stainless steel or the like that has a small amount of degassing.

With the above structure, gas leakage from the inside and intrusion of impurities from the outside can be prevented, and dust generated from the adjusting mechanism can be isolated from the gas filling space. Thereby, contamination of the surface of the optical element inside the gas filling space can be prevented.

In this embodiment, the optical axis adjusting mechanism has been described manually. However, the adjusting mechanism may be automated.
At that time, even if impurities and the like are released from the actuator and its peripheral parts, it does not affect the internal space,
Similarly, contamination of the optical element surface can be prevented.

Third Embodiment Next, a description will be given of an embodiment of a device production method using the above-described exposure apparatus. FIG. 4 shows a micro device (IC or L
1 shows a flow of manufacturing semiconductor chips such as SI, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). In step 1 (circuit design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.
The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 5 shows a detailed flow of the wafer process step 4. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. Step 1
In step 4 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is printed and exposed on the wafer by the above-described exposure apparatus of the present invention. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the production method of this embodiment, it is possible to produce a highly integrated device which was conventionally difficult to produce at low cost.

[0037]

As described above, according to the exposure apparatus and the device manufacturing method of the present invention, a reaction product generated by a chemical reaction of impurities caused by illumination light, dust generated from a driving mechanism, etc. The contamination of the surface of the optical element in the optical container can be prevented, and the illuminance of the exposure light can be reduced and the illuminance unevenness can be eliminated. Also,
Provided is an exposure apparatus and a device manufacturing method capable of suppressing consumption of clean dry air and inert gas required for replacing gas in an optical container, improving workability during maintenance of a drive mechanism and the like, and reducing apparatus downtime. can do.

[Brief description of the drawings]

FIG. 1 is a schematic view of an exposure apparatus according to first to third embodiments of the present invention.

FIG. 2 is a plan view (a) and a sectional view (b) of a zoom lens system according to a first example of the present invention.

FIG. 3 is a sectional view of a first block of an illumination optical system according to a second embodiment of the present invention.

FIG. 4 is a flowchart of the device manufacturing method of the present invention.

FIG. 5 is a detailed flowchart of a wafer process of the device manufacturing method of the present invention.

[Explanation of symbols]

1: exposure light source, 2: leading optical system, 3: illumination optical system first block, 4: illumination optical system second block, 5: illumination optical system third block, 6: illumination optical system fourth block, 7:
Reticle, 8: projection optical system, 9: wafer, 10: substrate stage, 11: nitrogen supply source, 12: piping, 13: chamber, 14: beam shaping lens system, 15, 19, 23: folding mirror, 16: zoom Lens system, 17: Fly eye lens, 18: Relay lens system, 20: Projection lens system, 21: Lens, 22: Lens holder, 24: Straight cam barrel, 25: Zoom cam barrel, 26: Bearing, 27: O Ring, 28: gear, 29: motor, 3
0: cam follower, 31: lens barrel, 32: shading tube,
33: mirror holder, 34: adjusting screw, 35: bellows tube, 36: mirror box.

Claims (8)

[Claims] An exposure apparatus for illuminating a mask via an illumination optical system with exposure light from an exposure light source and projecting and exposing a pattern on the mask onto a photosensitive substrate via a projection optical system. The optical system and the projection optical system are
An optical element, a driving system for driving a driven element of the optical element, and an optical container housing the optical element and the driving system, wherein at least a part of the driving system is arranged in an external space of the optical container. An exposure apparatus, comprising: 2. The exposure apparatus according to claim 1, wherein the driven element is a lens. 3. The exposure apparatus according to claim 1, wherein the optical container has at least one inlet for introducing gas into the container and at least one outlet for exhausting gas from the container. 4. The exposure apparatus according to claim 3, wherein the optical container has a closed structure having no opening other than the inlet and the outlet. 5. The exposure apparatus according to claim 1, wherein the optical container has a sealed structure without any opening. 6. The exposure apparatus according to claim 1, wherein the gas charged into the optical container is an inert gas. 7. The exposure apparatus according to claim 1, wherein the exposure light source includes an excimer laser. 8. A device manufacturing method, comprising manufacturing a device using the exposure apparatus according to claim 1.