JPH07142319A - Light source device - Google Patents

Abstract

PURPOSE:To provide the light source device of a semiconductor manufacturing device for a stepper and the like, which can accurately measure the performance values of an optical part and can indicate the times of cleaning and replacement. CONSTITUTION:An illuminance sensor 11 is inserted into a light emitting surface of a mercury lamp 1, and the illuminance of the mercury lamp 1 is measured. Then, the illuminance sensor 11 is inserted into the light radiation surface of an elliptical surface mirror 2, the illuminance is measured and the illuminance ratio of the light source is obtained. The illuminance ratios of a lens, a plane mirror and the like are computed based on the luminances of the respective light at the incident side and the emitting side. The illuminance sensor 11 is outputted and inputted on an optical path with a linear actuator. A CPU 18 judges the deterioration of the performance of the optical part based on the illuminance ratio and indicates the times of cleaning, replacement and the like for a CRT, a printer and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device such as a semiconductor manufacturing exposure apparatus, and more particularly to a light source device capable of managing the life of a mercury lamp, a laser light source or the like.

[0002]

2. Description of the Related Art A light source device such as a mercury lamp and a laser used in a semiconductor manufacturing apparatus is required to have high irradiance and uniform irradiance, and in order to maintain these performances, a mercury lamp, laser, The optical parts are regularly replaced and cleaned. For this reason, optical filters with exposure wavelengths have been replaced in a relatively short period of time as long-life products because the multilayer vapor-deposited film such as the oxide film easily changes depending on the environment.
Other optical components such as lenses and reflecting mirrors, which are not recognized as having a limited life, are expensive and have been used for a long time.

Further, although the optical parts which need to be cleaned have been periodically cleaned, there are many cases in which those which do not need to be cleaned are included, and further, the cleaning may cause unnecessary damage. The cost and time required for such maintenance has been a heavy burden. Further, when a part suddenly deteriorates, it takes a lot of time to specify the deteriorated part, which also imposes a heavy burden on the user of the apparatus. Further, in the stepper, the irradiance of the object plane or the image plane of the projection lens is manually or automatically measured to grasp the characteristics of the entire optical system, but the characteristic change of each optical component cannot be grasped.

In Japanese Patent Laid-Open No. 61-176115, a spare lamp is provided in addition to the exposure lamp, and when the irradiation intensity of the exposure lamp falls below a predetermined value, the spare lamp is switched to the predetermined lamp. Moving to a position is disclosed. Further, Japanese Patent Laid-Open No. 3-6011 discloses that the light energy of the exposure light source is controlled by measuring the light of the exposure light source for each wavelength. In addition, JP-A-60-198
Japanese Patent Publication No. 724 discloses that an illuminance distribution measuring device that can be put in and taken out is arranged between a projection exposure light source and an exposure original plate. Further, Japanese Patent Application Laid-Open No. 61-267323 discloses that the exposure illuminance is monitored and controlled by an optical fiber provided in the optical system of the semiconductor manufacturing apparatus.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to manufacture a semiconductor in which the characteristics of optical components can be individually grasped to solve the above problems, and the costs for replacement and cleaning of optical components can be reduced. To provide a device.

[0006]

In order to solve the above-mentioned problems, the illuminance ratio between the incident light and the emitted light of an optical component such as a reflecting mirror or a lens in the light source device, or the emitted light of a lamp constituting the above-mentioned light source. And the illuminance ratio of the light emitted from the ellipsoidal mirror is measured, and an alarm is generated when the measured illuminance ratio is out of the allowable range. Also, the allowable range value of the illuminance ratio and the current change value of the illuminance ratio or the measured illuminance ratio are displayed. Further, the illuminance sensor is put in and taken out of the optical path of the light source device to measure the illuminance ratio.

[0007]

In the measurement of the illuminance ratio, the ratio between the incident light and the emitted light of the optical component is obtained, so that the influence of the absolute sensitivity of the illuminance sensor is eliminated. Therefore, the influence of the temporal change of the absolute sensitivity of the illuminance sensor is mitigated. Alternatively, the user of the light source device is notified of the maintenance, cleaning, replacement time, etc. of the light source device by displaying the above-mentioned alarm or the allowable range of the illuminance ratio and the time-dependent change value of the current illuminance ratio or the measured illuminance ratio. . Further, the moving means of the illuminance sensor inserts the illuminance sensor into the incident light and the emitted light of the optical component when measuring the illuminance ratio, and moves so as to pull out from the optical path when the illuminance ratio is not measured.

[0008]

FIG. 1 is a basic block diagram of an exposure optical system of a stepper equipped with a light source device according to the present invention. The light from the mercury lamp (primary light source) 1 is condensed by the ellipsoidal mirror 2 and made into substantially parallel light by the lens 3 provided near the second focal point. After passing through the filter 4, the parallel light passes through the fly-eye lens 5 for uniformly illuminating the original screen 8, and further passes through the aperture 6 that determines the coherence, and then enters the collimation lens 9 through the lens 7. It The collimation lens 9 forms a fly-eye image (secondary light source image) on the entrance pupil of the reduction projection lens 10. Reference numerals 20 and 21 are plane mirrors for bending the optical path. An imaging optical system of a masking blade for limiting the exposure area of the original image pattern may be provided inside the light source device. Further, each of the above optical components is vapor-deposited to improve the transmittance and the reflectance.

In the present invention, when the illuminance ratio between the incident light side and the outgoing light side of the optical component such as the lens or the plane mirror is measured to obtain the illuminance ratio, and the illuminance ratio deviates from a predetermined range due to deterioration with time or the like. A warning is generated, and the temporal characteristics of the illuminance ratio are displayed together with the predetermined range so that the user can properly inspect, clean and replace the optical component.

Further, as shown in FIG. 1, when the optical component is a light source composed of a mercury lamp 1 and an ellipsoidal mirror 2, the horizontal irradiance of the mercury lamp 1 and the illuminance of condensed light of the ellipsoidal mirror 2. Is measured and the ratio is defined as the illuminance ratio. In the measurement of the illuminance ratio, the absolute sensitivity of the illuminance sensor and its variation with time do not pose a problem, so that there is an advantage that the performance management of the illuminance sensor is easy.

In the present invention, the illuminance ratio at the time of completion of assembly and adjustment of the light source device is stored as an initial value, and an alarm is generated when the illuminance ratio thereafter exceeds the allowable range of the characteristic change of the optical component. Also, it is displayed on a CRT, a printer, or the like.

When the illuminance before the intervention of the optical component is A and the illuminance after the intervention is B in the initial stage, the illuminance ratio C is C
= B / A. Similarly, when the illuminance ratio after the characteristic change is C ′, the change amount D of the illuminance ratio can be expressed by D = C / C ′. In the present invention, an alarm or message is displayed when the value of D becomes less than the allowable value. For example, the initial value of C is 10
0 and when C ′ is 95 or less, that is, D ≧
When 1.05 is reached, a message prompting cleaning and replacement is displayed on the CRT. The allowable value of D is determined for each light source device and optical component.

Further, although D generally changes gradually,
Since it is possible that the value changes abruptly on the way, the value of D may be recorded periodically and an alarm or a message may be displayed when the rate of change exceeds a predetermined value. Alternatively, the message may be issued by monitoring both the value of D and the rate of change thereof.

In FIG. 1, a small hole 2a for measuring the horizontal irradiance of the mercury lamp 1 is provided in the center of the ellipsoidal mirror 2 and an optical fiber 16 guides the light of the mercury lamp 1 to the illuminance sensor 11. The output of the illuminance sensor 11 is amplified and A / D converted by the amplifier 17, and stored in the CPU 18. When measuring the reflected light from the ellipsoidal mirror 2, the illuminance sensor 11 is moved from the emission position of the optical fiber 16 to the reflected light position of the ellipsoidal mirror 2.

FIG. 2 is a diagram showing the mechanism for measuring the irradiance ratio. When measuring the irradiance of the mercury lamp 1, the illuminance sensor 11 attached to the tip of the guide 13 by the linear actuator 12 is moved in the direction orthogonal to the optical axis of the mercury lamp 1 to enter the optical path of the mercury lamp 1, When measuring the irradiance of the ellipsoidal mirror 2, the illuminance sensor 11 is moved by the linear actuator 12 in the optical axis direction of the ellipsoidal mirror 2 to measure the irradiance. The position of the mercury lamp 1 is adjusted in advance in the X, Y, and Z directions by the stage so that the illuminance on the original screen is high and symmetrical uniformity is obtained.

The illuminance sensor 11 is a linear actuator 1.
The photoelectric conversion element 11a is attached to the tip of the second electrode, and is composed of a filter 11b that transmits the measurement wavelength.
The linear actuator 12 moves the illuminance sensor 11 in the direction orthogonal to the optical axis of the exposure optical system to enter the optical path when measuring the illuminance ratio. The linear actuator 12 is mounted on a carriage 14 and is mounted on a pair of guides 13 installed parallel to the optical axis. Truck 1 on the guide 13
Reference numeral 4 transmits the rotation of the drive source 14c to two axles of the four wheels 14a by means of the belt 14b and moves.

The photo interrupter 15 detects the movement amount of the carriage 14 and stops the carriage 14 at a predetermined position. The photo interrupter 15 may detect the position of the carriage 14 by coding it.

[0017]

According to the present invention, it is possible to provide a light source device capable of measuring the performance of an optical component without being affected by the fluctuation of the absolute sensitivity of the illuminance sensor. Also, by displaying the performance values of the optical components, cleaning of the optical components,
It is possible to notify the device user of the replacement time and the like. Further, it is possible to provide a semiconductor manufacturing apparatus such as a stepper in which the maintainability of optical components is improved by using the above light source device.

[Brief description of drawings]

FIG. 1 is a block diagram of a light source device according to the present invention.

FIG. 2 is a partial view of a moving mechanism of the illuminance sensor in FIG.

[Explanation of symbols]

1 ... Mercury lamp, 2 ... Ellipsoidal mirror, 3, 7 ... Lens, 4 ... Filter, 5 ... Fly eye lens, 9 ... Collimation lens, 11 ... Illuminance sensor, 12 ... Linear actuator,
13 ... Guide.

Claims (5)

[Claims] 1. A light source device for guiding and utilizing emitted light of a light source by an optical component such as a reflecting mirror or a lens, comprising means for measuring an illuminance ratio of incident light and emitted light of the optical component. Light source device. 2. In a light source device which uses the light emitted from a light source by guiding it through optical parts such as a reflecting mirror and a lens, the light source is composed of a lamp and an ellipsoidal mirror, and the light emitted from the lamp and the ellipsoidal mirror are emitted. A light source device comprising means for measuring the illuminance ratio of the emitted light. 3. The light source device according to claim 1, further comprising moving means for moving at least an illuminance sensor of the illuminance ratio measuring means into and out of an optical path of the light source device. 4. The method according to any one of claims 1 to 3,
A light source device comprising: a memory that stores an allowable range value of the illuminance ratio; and a unit that issues an alarm when the measured illuminance ratio is outside the allowable range of the illuminance ratio. 5. The light source device according to claim 4, further comprising means for displaying an allowable range value of the illuminance ratio and a current illuminance ratio or a temporal change value of the measured illuminance ratio.