JPH11233423A - Shutter for exposure, aligner, and manufacture of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote increase in the speed of shutter opening/closing operation, by using a plurality of small and light shutter vanes for locally to mnterrupting the beam cross section of an exposure light, and significantly improve the productivity of semiconductor devices. SOLUTION: A shutter 14 made up of a pair of rotary shutter units 40a and 40b is provided in the optical path of an exposure light to be exposed to a wafer or the like, and the rotary shutter units 40a and 40b are synchronously rotated by motors 45a and 45b. The beam cross section of the exposure light is interrupted by, for example, sectors 43a and 43b of the rotary shutter units 40a and 40b. The sectors 43a and 43b can be smaller than in the case where the entire beam cross section of the exposure light is interrupted by a single sector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure shutter and an exposure apparatus used for an exposure apparatus for manufacturing a high-definition semiconductor device and the like, and a device manufacturing method.

[0002]

2. Description of the Related Art In the production of semiconductor devices and the like,
Generally, a reduction projection exposure apparatus (hereinafter, referred to as a “stepper”) that reduces a pattern of an original such as a reticle by a reduction projection lens and projects the pattern on a substrate such as a wafer is used.
In this method, a process of stepwise moving an XY stage on which a wafer is mounted and an exposure process are alternately repeated to transfer and print dozens of original patterns such as a reticle onto a single wafer.

In recent years, in order to improve the productivity of the stepper, efforts have been made to shorten the exposure cycle time by increasing the opening / closing speed of a shutter disposed in the optical path of the exposure light. Further, in order to increase the exposure speed, the sensitivity of resist applied to a wafer or the like has been rapidly increased.

As a shutter of a light source optical system that generates exposure light, a rotary shutter or the like that blocks exposure light with one shutter blade has been used (Japanese Patent Application Laid-Open No. 9-2).
No. 7446).

[0005]

However, according to the above prior art, as described above, the shutter of the light source optical system for generating the exposure light is shielded by inserting one shutter blade into the optical path of the exposure light. Therefore, it is necessary to make the size of the shutter blade larger than the beam cross section of the exposure light.

If the shutter blade absorbs the heat of the exposure light when the shutter is closed, the shutter blade may be deformed or melted. Therefore, in general, the surface of the shutter blade is mirror-finished to expose the exposure light. However, when the exposure light reflected by the shutter blades moves backward toward the light source, heat fluctuation occurs in the light source. Therefore, to prevent the reflected light of the shutter blade from going back to the light source,
Generally, the shutter blades are inserted obliquely with respect to the optical path of the exposure light, so that the beam cross section of the light beam blocked by the shutter blades becomes elliptical.

Therefore, in order to shield light with one shutter blade, the size of the shutter blade must be much larger than the beam cross section perpendicular to the optical path.

On the other hand, in order to improve the throughput of the exposure apparatus, it is necessary to increase the opening / closing speed of the shutter. However, as described above, the shutter blade having a large size and a large moment of inertia has a limitation in increasing the speed of the shutter. .

In order to reduce the size of the shutter blade, the beam width is reduced by narrowing the exposure light, or the shutter blade is made lighter by selecting a material that is lightweight and excellent in heat resistance. Method is adopted,
A sufficient effect cannot be expected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and has a shutter opening / closing operation by using a plurality of small and lightweight shutter blades for locally blocking a beam cross section of exposure light. It is an object of the present invention to provide an exposure shutter, an exposure apparatus, and a device manufacturing method capable of promoting a high-speed operation and greatly improving the productivity of semiconductor devices and the like.

[0011]

In order to achieve the above object, an exposure shutter according to the present invention comprises: a plurality of rotary shutter units for locally shielding a beam cross section of exposure light generated from a light source; A drive unit for synchronously rotating a plurality of rotary shutter units is provided, and a control unit for controlling the drive unit based on an exposure amount of the object to be exposed by the exposure light.

Preferably, each rotary shutter unit has at least one shutter blade.

It is preferable that each rotary shutter unit is configured to insert a shutter blade obliquely to an optical path of exposure light.

[0014]

By rotating the plurality of rotary shutter units synchronously and simultaneously inserting the shutter blades of each rotary shutter unit into the optical path of the exposure light, the entire beam cross section of the exposure light is shielded. The size of each shutter blade can be greatly reduced and the weight can be reduced as compared with the case where the entire cross section of the exposure light beam is shielded by one shutter blade. Thus, the moment of inertia of each shutter blade can be reduced, and the speeding up of the shutter can be greatly promoted.

If each rotary shutter unit has a plurality of shutter blades on its rotation axis, the shutter can be opened and closed a plurality of times by rotating the rotary shutter unit once.

If each rotary shutter unit is configured to insert the shutter blade obliquely with respect to the optical path of the exposure light, it is possible to prevent the reflected light from the shutter blade from traveling backward to the light source. .

[0017]

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

FIG. 1 shows an exposure apparatus according to one embodiment, which comprises a mercury lamp 11 as a light source and an elliptical mirror 12 for condensing exposure light generated from the mercury lamp 11.
A first lens 13 for narrowing the light beam of the exposure light; a shutter 14 as an exposure shutter; a second lens 15 for returning the light beam narrowed by the first lens 13 to parallel light; Light source optical system 10 including a half mirror 16 for taking out light
A reticle stage 21 on which a reticle R as an original having a pattern to be transferred to each shot of a wafer W to be exposed (substrate); a reduction projection lens 22 for reducing and projecting the pattern on the reticle R onto the wafer W; , A θZ tilt stage 31 that carries the wafer W and moves in the optical axis direction, and an XY stage 32 that moves the wafer W in the XY directions. The XY stage position is measured by the laser interferometer 33.

As shown in FIG. 2, the shutter 14 has a pair of rotary shutter units 40a and 40b, and one of the rotary shutter units 40a is inserted into three shutters obliquely with respect to the optical path of the exposure light. The upper half or more of the beam cross section of the exposure light is locally shielded sequentially by the blades 41a to 43a, and similarly, the other rotary shutter unit 40b
Also, the shutter blades 41b to 43b inserted obliquely with respect to the optical path of the exposure light are configured to sequentially locally shield the lower half or more of the beam cross section of the exposure light.

The three shutter blades 41a-43a, 41b-43b of each rotary shutter unit 40a, 40b
Forms a light-shielding portion having a central angle of 60 ° around the rotation shafts 44a and 44b at intervals of 60 ° in the circumferential direction. The rotary drive unit of each rotary shutter unit 40a, 40b includes a rotary shaft 44.
motors 45a,
45b, and rotary encoders 46a and 46b for detecting the rotational position thereof.
Are connected to a controller 50 as control means via motor drivers 47a and 47b. The controller 50 controls the opening time of the shutter 14 based on the output of the photodetector 17 that detects a part of the exposure light extracted by the half mirror 16 so that the integrated exposure amount of the wafer W becomes a predetermined value.

The rotary shutter units 40a, 40
b is the shutter blades 41a to 43a, 4 as described above.
1b to 43b are inserted obliquely with respect to the optical path of the exposure light, the driving unit including the motors 45a, 45b, etc., controls the shutter blades 41a to 43a, 41b so as not to block the optical path of the exposure light. 43b are disposed on opposite sides of each other.

FIG. 3 is a schematic view showing the opening and closing operation of the shutter 14. In order to make the integrated exposure amount of the exposure area of the wafer W uniform, each of the shutter blades 41a to 43a and 41b to 43
Since both edges of b need to have the same shape that crosses the exposure light, as described above, the disk has a shape in which the light shielding portion and the opening are provided at intervals of 60 °. Further, the arc portions of the shutter blades 41a to 43a and 41b to 43b are overlapped with the positions where the cross section of the beam of the exposure light is bisected so that the two rotary shutter units 40a and 40b always have a constant light shielding shape. .

The hatched area in FIG.
Is a beam cross section of the exposure light to be shielded. As aforementioned,
Since the shutter blades 41a to 43a and 41b to 43b are inserted obliquely with respect to the exposure light, the shape (beam cross section) of the exposure light beam in the light shielding portion of the shutter 14 is elliptical.

That is, the mercury lamp 1 of the light source optical system 10
1 is strong, the shutter blades 41a to 43a, 4
1b to 43b may be prevented from being melted or deformed by heat. Therefore, the shutter blades 41a to 43b and 41b to 43b are exposed to the exposure light so that the surface of the shutter blades is mirror-finished and the reflected light does not return to the mercury lamp 11 and the illuminance does not change due to the temperature change. It is inserted obliquely.

The operation of opening and closing the shutter 14 will be described below. From the light blocking state (shutter closed) shown in FIG.
The upper rotating shutter unit 40a moves clockwise in the drawing,
When the lower rotary shutter unit 40b is rotated by 15 ° in the counterclockwise direction in the drawing, a part of the exposure light is transmitted as shown in FIG. When the rotary shutter units 40a and 40b rotate by 60 °, the shutter 14 is fully opened (shutter open) as shown in FIG.
And the wafer W is exposed.

At the end of the exposure, when the rotary shutter units 40a and 40b continue to rotate in the same manner and rotate by 15 °, a part of the exposure light is blocked as shown in FIG. When half of the exposure light is shielded as shown in (e) of the figure and the shutter is rotated by 60 °, the shutter is closed as shown in (f) of the figure. Thus, each of the rotary shutter units 40a and 40b is
The shutter 14 is opened and closed by intermittently rotating by degrees.

According to the present embodiment, the shutter is opened and closed by two shutter blades that shield at least half of the beam cross section of the exposure light. Therefore, the shutter is opened and closed by one shutter blade. As compared with the case, the shutter blades can be made much smaller, and the moment of inertia when rotating the shutter blades can be reduced. This can greatly accelerate the shutter speed.

More specifically, FIG. 4 shows the shape of the shutter blade A according to the present embodiment by a solid line, and shows the shape of the conventional shutter blade B by a broken line. The formula for calculating the moment of inertia J of the shutter is expressed as follows: J = Jsh + Jmh (1) where Jsh is the moment of inertia of the shutter blade portion and Jmh is the moment of inertia of the motor holder portion. Moment of inertia Jsh of shutter blade part
Is の of the moment of inertia of a disk of the same diameter.
Assuming that the diameter of the rotating shaft is D ₁ , the diameter of the shutter blade A is D ₂ , the diameter of the shutter blade B is D ₃ , the specific gravity of the material is ρ, and the plate thickness of the shutter blades A and B is L, respectively. moment of inertia Jnew shutter blade ^{_{portion, Jnew = πρL (D 2 4}} -D 1 4) / 32 × 1/2 (2) the moment of inertia J of the shutter blade portion of the shutter blade B
old ^{_{is, Jold = πρL (D 3 4}} -D 1 4) / 32 × 1/2 (3) and expressed. In this embodiment, Jold> Jnew >> Jmh (4 ) D 1: D 2: D 3 ≒ 1: 4: 6 (5) because it is a relationship, of the shutter blade portion of the shutter blade A and the shutter blade B The ratio of the moment of inertia to the shutter blade portion is Jnew: Jold ≒ 1: 5 (6). That is, the shutter according to the present embodiment can reduce the moment of inertia to about 1/5 as compared with the conventional shutter. Next, the exposure cycle of the wafer W will be described.

The mercury lamp 11 is always lit, and before the start of exposure, for example, the exposure light is blocked by shutter blades 41a and 41b. The controller 50 monitors the rotary encoders 46a and 46b, and
Servo is applied to 7a and 47b to control the rotational position of the rotary shutter units 40a and 40b.

When an exposure start command is issued, the controller 50 starts monitoring the photodetector 17, and the motor drivers 47a and 47b send the rotation shutter units 40a and 40b.
A signal for rotating 60b by 60 ° is sent to the motors 45a, 4b.
5b is driven. Thus, the shutter 14 is opened.

The controller 50 is a photo detector 17
When the integrated exposure amount is measured by integrating the outputs of the motor driver and the desired integrated exposure amount is obtained, the controller 50 sets the motor driver 4
A signal for further rotating 60 ° is sent to 7a and 47b to drive the motors 45a and 45b. Thus, the shutter 14 is closed and the exposure is completed.

The controller 50 includes a motor 45a,
While driving the rotary encoder 45b, the rotary encoders 46a, 46b
Is monitored, the speed servo is applied to the motor drivers 47a, 47b, and the shutter blades 41a-43a, 41b-43
The speed-position characteristics during acceleration, constant speed, and deceleration of b are controlled.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 5 shows a manufacturing flow of a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD). Step 1
In (circuit design), the circuit of the semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern designed. Step 3
In (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 prepared mask and wafer. 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). . 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. 6 shows a detailed flow of the wafer process. 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. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer. 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 manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device which has been conventionally difficult to manufacture.

[0035]

Since the present invention is configured as described above, it has the following effects.

The shutter blades for shielding the exposure light can be significantly reduced in comparison with the beam cross section of the exposure light. As a result, the shutter blades can be reduced in size and weight, and the moment of inertia can be reduced, thereby greatly increasing the speed of the shutter. By mounting such an exposure shutter, the throughput of the exposure apparatus can be greatly improved, and the productivity of semiconductor devices and the like can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an exposure apparatus according to one embodiment.

FIGS. 2A and 2B show a part of the apparatus shown in FIG. 1, wherein FIG. 2A is a view for explaining a shutter and a drive unit thereof, and FIG. 2B is a view showing a shape of a shutter blade.

FIG. 3 is a diagram illustrating an opening and closing operation of a shutter.

FIG. 4 is a diagram illustrating a difference in shape between a shutter blade according to the present embodiment and a shutter blade according to a conventional example.

FIG. 5 is a flowchart showing a device manufacturing method.

FIG. 6 is a flowchart showing a wafer process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Mercury lamp 14 Shutter 20 Projection optical system 21 Reticle stage 22 Reduction projection lens 30 Wafer stage 40a, 40b Rotation shutter unit 41a-43a, 41b-43b Shutter blade 44a, 44b Rotation axis 45a, 45b Motor 50 Controller

Claims (5)

[Claims] A plurality of rotary shutter units each of which locally blocks a beam cross section of exposure light generated from a light source; a driving unit for synchronously rotating the plurality of rotary shutter units; An exposure shutter having control means for controlling the driving means based on an exposure amount of the object to be exposed by light. 2. A rotary shutter unit comprising at least one
2. The exposure shutter according to claim 1, further comprising a plurality of shutter blades. 3. The exposure shutter according to claim 2, wherein each rotary shutter unit is configured to insert a shutter blade obliquely with respect to an optical path of exposure light. 4. An exposure apparatus comprising: the exposure shutter according to claim 1; and holding means for holding an object to be exposed, which is exposed by exposure light irradiated through the exposure shutter. 5. A device manufacturing method comprising a step of exposing a wafer by the exposure apparatus according to claim 4.