JPH10294271A - Illuminating system, aligner and device manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constantly illuminate a plane to be illuminated with a stable illuminance, by detecting the temperature of a illuminance sensor, and cooling the illuminance sensor based on the detected temperature so as to maintain the temperature of the illuminance sensor at a prescribed value. SOLUTION: A differential amplifier 32 amplifies a signal provided based on a difference between a signal from an illuminance sensor 1 and an instruction signal from an illuminance instruction part 33, which outputs the signal for previously setting the illuminance on the plane of a subject to be illuminated, and outputs it as a power control signal. The power control signal from the differential amplifier 32 is converted into power by a lighting device 31, and the light emitting quantity of a lamp 11 is controlled. A heat dissipating tin 2 is mounted on the rear plane of the illuminance sensor 1, and temperature increase of the illuminance sensor 1 is suppressed. The illuminance sensor 1 is provided with a temperature sensor 4, and temperature change is fetched to a temperature control part 5. The temperature control part 5 controls the rotating speed of a fan 3 through a rotating speed control part 6 so as to have the temperature of the illuminance sensor 1 within a set range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Generally, in order to achieve a high throughput when a circuit pattern on a reticle surface illuminated with exposure light from an illumination device is projected onto a wafer surface by a projection optical system, an exposure lamp is required. It is necessary to increase the amount of light from the camera. Thereby, it is possible to easily increase the exposure speed and increase the throughput. Also, keeping the light amount from the light source means constant at all times can stabilize the throughput. Therefore, a part of the luminous flux from the lamp is taken into the illuminance sensor, and the power to the lamp is feedback-controlled. However, when the power to the lamp is increased as shown in FIG. 8 with the lighting time by the feedback control in order to keep the illuminance of the reticle and the wafer surface constant, the light emission of the lamp is maintained but the heat generation is reduced by the current. Increase in proportion. The heat energy heats the illuminance sensor, and the temperature of the illuminance sensor rises as shown in FIG. Then, the photoelectric conversion characteristics of the constant illuminance sensor together with the temperature are shown in FIG.
And the output of the illuminance sensor includes an error, so that the illuminance of the illumination system is not constant.

In order to determine an exposure amount, a stepper takes in a part of a light beam in an illumination system into an illuminance sensor and controls a shutter opening / closing speed based on the illuminance value. An increase in the temperature of the illuminance sensor causes an error in the illuminance value, so that accurate illuminance cannot be grasped.

Therefore, conventionally, as shown in FIG. 7, a radiation fin 2 is attached to a photodetector 1 (illuminance sensor) to suppress a temperature rise of the photodetector 1.
(FIG. 7)

[0005]

If the power specification of the lamp is increased in order to improve the throughput, the gradient of the temperature rise of the illuminance sensor for feedback becomes large, and it becomes impossible to radiate heat only with the radiation fins. (FIG. 9). The light receiving sensitivity of a silicon-based or gallium arsenide-based photodiode used in a constant illuminance sensor changes with an increase in temperature. Therefore, a rise in the temperature of the illuminance sensor causes an error in the power feedback signal (FIG. 10), so that the illuminance of the illumination system is not constant (FIG. 1).
1).

For example, when a gallium arsenide-based photodiode is used for the illuminance sensor, the temperature characteristic of the light receiving sensitivity is-
0.2%. When a 3 KW lamp is used for the illumination system, the temperature of the illuminance sensor increases by about 20 ° C. with respect to the room temperature of 23 ° C. That is, the output of the illuminance sensor is reduced by 4% from the initial lighting. Similarly, when a 5KW lamp is used, the temperature rises to about 40 ° C., so that the output of the illuminance sensor is reduced by 8% from the initial lighting. Further, when the lamp is turned on in the constant illuminance mode, the temperature of the illuminance sensor increases with an increase in power, and the output of the illuminance sensor decreases. Thus, the output of the illuminance sensor changes with the temperature. In a system where power feedback control is performed, the illuminance on the mask or plate surface cannot be kept constant. Further, in the stepper, there is a problem that the exposure amount is not appropriate because the illuminance value of the illuminance sensor includes an error.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to illuminate a surface to be illuminated by an illuminating device with a stable illuminance at all times, so that a semiconductor device can be stably provided with high accuracy. An object of the present invention is to enable manufacturing with high throughput.

[0008]

According to the present invention, there is provided a lighting device for controlling a light emission amount by feeding back a detection signal of an illuminance sensor and controlling electric power to be used. It is characterized by having temperature detecting means for detecting the temperature of the sensor and cooling means for maintaining the temperature of the illuminance sensor at a predetermined value based on the output thereof. Further, the exposure apparatus of the present invention is characterized in that a predetermined pattern is exposed on a substrate by such an illumination device.

Further, according to the device manufacturing method of the present invention, the detection signal of the illuminance sensor is fed back, and a predetermined pattern is exposed on the substrate by using an illuminating device which controls the amount of light emission by controlling the power to be used. In the method for manufacturing a device, upon exposure, the temperature of the illuminance sensor is detected, and the illuminance sensor is cooled such that the temperature of the illuminance sensor is maintained at a predetermined value based on the detected temperature. Features.

In the above configuration, the temperature of the illuminating device rises with the lighting time of the illuminating device, but the temperature of the illuminance sensor is maintained at a predetermined value. The control of the light emission amount of the lighting device based on it is also performed accurately. Therefore, even when large power is used, the surface to be irradiated is always illuminated with a stable illuminance.

[0011]

In a preferred embodiment of the present invention, the cooling means includes a radiating fin attached to the illuminance sensor, a means for blowing air to the fin, and a flow rate of the fin based on an output of the temperature detecting means. Control means. Hereinafter, examples which are more specific embodiments of the present invention will be described.

[0012]

FIG. 1 is a schematic view of a main part of an illumination apparatus and a projection exposure apparatus using the same according to an embodiment of the present invention. In the figure,
Reference numeral 12 denotes an elliptical mirror, and reference numeral 11 denotes a mercury lamp having a high-luminance light-emitting portion that emits ultraviolet light and ultraviolet light. The light emitting part of the lamp 11 is arranged near the first focal point of the elliptical mirror 12. The lamp 11 is lit with the power from the lighting means 31, that is, the light emission amount of a value corresponding to a power control signal described later. 1
Reference numeral 3 denotes a cold mirror, which is formed of a multilayer film and transmits most infrared rays and reflects most ultraviolet rays. 1
Reference numeral 9 denotes a condenser lens, which forms a light beam from the elliptical mirror 12 on the incident surface of the fly-eye lens 20 via the mirror 14. The fly-eye lens 20 has a plurality of microlenses arranged two-dimensionally at a predetermined pitch, and forms a secondary light source on the exit surface side of the fly-eye lens 20.

A plurality of light beams emitted from the secondary light source on the exit surface side of the fly-eye lens 20 are condensed by a condenser lens 21 via a mirror 15, and most of the light beams are reflected by a half mirror 16 and reflected on a surface 24. Provide uniform illumination. Reference numeral 22 denotes a shutter,
4 is provided in the vicinity. Reference numeral 23 denotes a slit, which allows a part of the light beam condensed on the surface 24 to pass. 17, 1
Reference numeral 8 denotes a condensing system including a concave mirror and the like, which uniformly irradiates the reticle 41 with a light beam passing through the opening of the slit 23. Reference numeral 1 denotes an illuminance sensor which detects the luminous flux transmitted through the half mirror 16 and measures the illuminance of the surface 24, that is, the illuminated surface 41. Reference numeral 42 denotes a projection optical system, and the reticle 4
The circuit pattern on one surface is imaged on the wafer (or substrate) 43 surface.

Numeral 32 denotes a differential amplifier, which amplifies a signal generated from a difference between a signal from the illuminance sensor 1 and a command signal from an illuminance command unit 33 for outputting a signal for presetting the illuminance on the surface to be illuminated. , As a power control signal. In this embodiment, the power control signal from the differential amplifier 32 is
Is converted to electric power, and based on the magnitude of the electric power, the lamp 11
The amount of light emission is controlled.

On the other hand, the radiation fins 2
To reduce the temperature rise of the illuminance sensor 1. Further, a temperature sensor 4 is attached to the illuminance sensor 1, detects a temperature change of the illuminance sensor 1, and takes in the temperature control unit 5.
The temperature control unit 5 controls the rotation speed of the fan 3 via the rotation speed control unit 6 so that the temperature of the illuminance sensor 1 falls within the set range. The air flow generated by the fan 3 flows along the radiation fins 2 to remove heat and keep the temperature of the illuminance sensor 1 constant.

FIG. 2 shows another embodiment using compressed air for cooling the temperature sensor 1. In this case, compressed air is used instead of the fan 3. That is, the flow rate of the compressed air blown by the nozzle 8 to the radiation fins 2 via the flow rate control means 7 is controlled based on a command from the temperature control section 5. Flow control means 7
, An electro-pneumatic servo valve or the like is used. As a method of cooling the illuminance sensor, a method of circulating a liquid refrigerant and controlling the flow rate thereof may be used.

(Effects of the Embodiments) According to the above-described embodiments, the following effects can be obtained. From the beginning to the end of the lamp life, the illuminance of the illumination system can be stably kept constant. There is no need to correct the illuminance deviation in the illuminance check in daily inspection. That is, in the case of the conventional method, the illuminance of the illumination system gradually increases (FIG. 11). This hassle-free. In the conventional method, even if the illuminance is corrected in the daily inspection, the illuminance slightly increases during one day. That is, the input power to the lamp has risen, resulting in a loss. In each embodiment, since such a loss is eliminated, the life of the lamp (lighting time)
Extends.

Next, a description will be given of a device manufacturing example which can utilize the exposure apparatus and the device manufacturing method. FIG. 12 shows a micro device (a semiconductor chip such as an IC or an LSI,
2 shows a flow of manufacturing a liquid crystal panel, a CCD, a thin-film magnetic head, a micromachine, and the like. Step 31 (circuit design)
Now, the circuit design of the semiconductor device will be performed. Step 32
In (mask production), a mask on which a designed circuit pattern is formed is produced. On the other hand, in step 33 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 34 (wafer process) is referred to as a preprocess, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. Next step 35
The (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 34, and includes an assembly process (dicing, bonding),
It includes steps such as a packaging step (chip encapsulation). In step 36 (inspection), inspections such as an operation check test and a durability test of the semiconductor device manufactured in step 35 are performed. Through these steps, a semiconductor device is completed and shipped (step 37).

FIG. 13 shows a detailed flow of the wafer process. Step 41 (oxidation) oxidizes the wafer's surface. In step 42 (CVD), an insulating film is formed on the wafer surface. In step 43 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 44 (ion implantation), ions are implanted into the wafer. Step 4
In 5 (resist processing), a photosensitive agent is applied to the wafer. Step 46 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer. In step 47 (developing), the exposed wafer is developed. In step 48 (etching), portions other than the developed resist image are removed. In step 49 (resist removal),
After the etching, the unnecessary resist is removed.
By repeating these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of the present embodiment, a highly integrated semiconductor device, which has conventionally been difficult to manufacture, can be manufactured at low cost.

[0020]

As described above, according to the present invention, since the temperature of the illuminance sensor is kept constant as shown in FIG. 4, the power used makes the illuminance constant as shown in FIG. For this reason, even if it increases with the lighting time, the output of the illuminance sensor becomes constant as shown in FIG.
As shown in (2), the illuminance of the lighting device can be kept constant. In other words, there is no change in illuminance due to a rise in temperature of the illuminance sensor, and the surface to be irradiated can always be illuminated with stable illuminance. Therefore, semiconductor devices can be stably manufactured with high accuracy and high throughput.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an illumination device and a projection exposure apparatus using the illumination device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an illumination device according to another embodiment of the present invention and a projection exposure apparatus using the same.

FIG. 3 is a diagram showing a transition of lamp power with respect to a lamp lighting time in the lighting device of the present invention.

FIG. 4 is a diagram showing a transition of an illuminance sensor temperature with respect to a lamp lighting time in the lighting device of the present invention.

FIG. 5 is a diagram showing a transition of an illuminance sensor output with respect to a lamp lighting time in the lighting device of the present invention.

FIG. 6 is a diagram showing a change in illuminance of an illumination system with respect to a lamp lighting time in the illumination device of the present invention.

FIG. 7 is a diagram illustrating a conventional example.

FIG. 8 is a diagram showing a transition of lamp power with respect to a lamp lighting time in a conventional illumination device.

FIG. 9 is a diagram showing a transition of an illuminance sensor temperature with respect to a lamp lighting time in a conventional illumination device.

FIG. 10 is a diagram showing a transition of an illuminance sensor output with respect to a lamp lighting time in a conventional illumination device.

FIG. 11 is a diagram showing a change in illuminance of an illumination system with respect to a lamp lighting time in a conventional illumination device.

FIG. 12 is a flowchart showing a flow of manufacturing a micro device that can be manufactured by the apparatus of FIG. 1;

FIG. 13 is a flowchart showing a detailed flow of a wafer process in FIG. 12;

[Explanation of symbols]

1: illuminance sensor, 2: radiation fin, 3: fan, 4: temperature sensor, 5: temperature control unit, 6: rotation speed control unit, 7: flow control means, 8: nozzle, 11: lamp, 12: elliptical mirror , 13, 14, 15: mirror, 16: half mirror,
17, 18: condenser mirror, 19: condenser lens, 20: fly-eye lens, 21: condenser lens, 22:
Shutter, 23: slit, 24: light-collecting surface, 31: lighting means, 32: differential amplifier, 33: illuminance command unit, 41: first object surface, 42: projection optical system, 43: second object surface.

Claims (4)

[Claims] 1. An illumination device for controlling a light emission amount by feeding back a detection signal of an illuminance sensor and controlling electric power to be used, wherein the illuminance is detected based on an output of the temperature detection means for detecting a temperature of the illuminance sensor. A lighting device comprising cooling means for maintaining a temperature of a sensor at a predetermined value. 2. The cooling unit includes: a radiation fin attached to the illuminance sensor; a unit that blows air to the radiation fin;
2. The lighting device according to claim 1, further comprising means for controlling the air flow based on the output of said temperature detecting means. 3. An exposure apparatus, wherein a predetermined pattern is exposed on a substrate by the illumination device according to claim 1. 4. A method of manufacturing a device by exposing a predetermined pattern onto a substrate using an illumination device that controls a light emission amount by feeding back a detection signal of an illuminance sensor and controlling power to be used, A method for manufacturing a device, comprising: detecting a temperature of the illuminance sensor during exposure, and cooling the illuminance sensor based on the detected temperature so that the temperature of the illuminance sensor is maintained at a predetermined value.