JPH08162396A - Lighting device and projection light exposure device equipped therewith - Google Patents

Abstract

PURPOSE: To stably manufacture semiconductor devices high in accuracy and throughput by a method wherein a cooling means which cools down a light source basing on electrical power control signals is so controlled in operation as to restrain the light source from rising in temperature above a previously set value, and an illuminated surface is stably lighted constant in luminous intensity. CONSTITUTION: A reduction projection light exposure device serves to projects a pattern on the surface of a reticule 16 onto a wafer 54 as the pattern is reduced in size. A differential amplifier 56 amplifies signals formed of a difference between a signal sent from an illuminance sensor and an instruction signal outputted from an illuminance instruction section 55 which outputs signals to previously set the illuminated surface in illuminance and outputs them as a power control signal. The power control signal is converted into an electrical power through a lighting device 51, and a light source means 2 is controlled in light emission volume by the size of an electric power. On the other hand, a power control signal from the differential amplifier 56 is inputted into an airflow rate control device 52, whereby air jetted out of a nozzle 4 is controlled in flow rate in accordance with the size of the electric power control signal to forcibly cool down the light source means 2 to prevent it from rising in temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device and a projection exposure apparatus using the same, and in particular, in a manufacturing device for semiconductor devices such as ICs, LSIs, liquid crystal elements, etc., a light source means used for the illuminating device generates heat and temperature This is suitable for manufacturing a highly accurate and stable semiconductor device by preventing a decrease in luminous efficiency due to electrode deterioration that occurs when the temperature rises, maintaining good illuminance on the surface to be irradiated.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device manufacturing apparatus is required to have high resolution and high throughput.

Generally, in order to achieve high throughput when projecting and exposing a circuit pattern on a reticle surface illuminated by exposure light from an illuminating device onto a wafer surface by a projection optical system, a resist on the wafer surface is exposed in a short exposure time. In order to form a pattern by exposing it to light, it is necessary to increase the amount of light from the light source means for exposure. This makes it possible to increase the exposure speed and easily achieve high throughput.

However, when the electric power of the light source means is increased to increase the amount of emitted light, the electrode deterioration due to the heat generation of the light source is promoted and the life of the light source is shortened. In addition, the heat balance of the device due to heat generation is also deteriorated. In order to prevent such a situation, for example, in JP-A-62-36819, the temperature around the light source is detected by a temperature sensor, and the signal from the temperature sensor is fed back to the controller to rotate the electric fan. We have proposed a semiconductor printing exposure apparatus having a structure in which the air flow rate to the nozzles and nozzles is made variable by a temperature signal, thereby suppressing the heat generation of the light source.

[0005]

Generally, as a method of preventing a temperature rise due to heat generation of the light source means, a light source is provided by a cooling means using compressed air or cooling gas based on a signal from a temperature sensor provided around the light source means. The method of forcibly cooling the means has a feature that the temperature can be controlled with high accuracy.

However, in a projection exposure apparatus for manufacturing semiconductor devices, the allowable width of the light source means is generally as large as about 100 ° C. Therefore, it is not always necessary to use the temperature sensor or the control means to manage the temperature with high accuracy. Although the temperature sensor and the method of cooling the light source means using the signal from the temperature sensor can manage the temperature with high accuracy, there is a problem that the configuration of the entire device is inevitably complicated.

Generally, the amount of light emitted from the light source means used in the lighting device is controlled based on the power control signal.

The present invention utilizes the fact that the power control signal for controlling the amount of light emitted from the light source means has a substantially proportional relationship with the temperature of the light source means, and the cooling means for cooling the light source means based on the power control signal. By controlling the operation, the temperature of the light source means is prevented from rising above a preset temperature by a simplified control system without using a temperature sensor, and the illuminated surface is always illuminated with stable illuminance. It is an object of the present invention to provide an illumination device and a projection exposure apparatus using the same, which are capable of stably manufacturing with high precision and high throughput.

[0009]

[Means for Solving the Problems]

(1-1) The illumination device of the present invention is based on the power control signal when illuminating the surface to be illuminated through the illumination system with the light flux from the light source means whose light emission amount is controlled by the power control signal. It is characterized in that the light source means is forcibly cooled by the cooling means.

In particular, the cooling means has a flow rate control means for controlling the flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means to supply the light source. That the means is forcedly cooled,
The power control signal is generated using a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. And so on.

(1-2) In the projection exposure apparatus of the present invention, when the projection optical system projects the pattern on the first object plane illuminated by the luminous flux from the illumination means onto the second object plane, the illumination means operates. The first object surface is illuminated through the illumination system with the light flux from the light source means whose light emission amount is controlled by the power control signal, and the light source means is forcibly cooled by the cooling means based on the power control signal. It is characterized by

In particular, the cooling means has a flow rate control means for controlling the flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means to supply the light source. That the means is forcedly cooled,
The power control signal is generated using a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. And so on.

(1-3) In the method of manufacturing a semiconductor device of the present invention, after the pattern on the reticle surface illuminated by the luminous flux from the illumination means is projected and exposed on the wafer surface by the projection optical system,
When a semiconductor device is manufactured through a development process of the wafer, the illuminating means illuminates the reticle surface through a lighting system with a light flux from a light source means whose light emission amount is controlled by a power control signal. The light source means is forcibly cooled by the cooling means based on the power control signal.

In particular, the cooling means has a flow rate control means for controlling the flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means to supply the light source. That the means is forcedly cooled,
The power control signal is generated using a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. And so on.

[0015]

1 is a schematic view of a main part of a first embodiment of an illumination apparatus and a projection exposure apparatus using the same according to the present invention.

In the figure, 3 is an elliptical mirror. Reference numeral 2 denotes an arc tube as a light source means, which is composed of a mercury lamp or the like, and has a high-luminance light emitting section 2a which radiates ultraviolet rays, far ultraviolet rays and the like. The light emitting portion 2a is arranged near the first focus of the elliptical mirror 3. The light source means 2 is turned on with the electric power from the lighting means 51, that is, the amount of light emission corresponding to a power control signal described later. Four
a and 4b (4) are nozzles, respectively, and flow rate control means 52
Air (including compressed air, cooling air, cooling gas, etc.) controlled by is blown onto the light source means 2 to forcibly cool the light source means 2. The nozzle 4 and the flow rate control means 52 constitute one element of the cooling means. Reference numeral 5 denotes a cold mirror, which is composed of a multilayer film and transmits most of infrared light and reflects most of ultraviolet light. The elliptic mirror 3 forms a light emitting portion image (light source image) 2b of the light emitting portion 2a near the second focal point 3b via the cold mirror 5.

Reference numeral 11 denotes a lens system, which is composed of a condenser lens, a zoom lens and the like, and forms a light emitting portion image 2b formed in the vicinity of the second focal point 3b on the entrance surface 12a of the optical integrator 12 via the mirror 6. The optical integrator 12 is configured by arranging a plurality of minute lenses (fly's eye lenses) 12i (i = 1 to N) two-dimensionally at a predetermined pitch, and forms a secondary light source in the vicinity of its exit surface 12b. are doing. A stop 12c is located on the secondary light source surface near the exit surface 12b of the optical integrator 12. 7 is a mirror. Reference numeral 13 is a condenser lens.

A plurality of light beams emitted from the secondary light source in the vicinity of the emission surface 12b of the optical integrator 12 are condensed by the condenser lens 13 via the mirror 7, and a part thereof is a half mirror surface. The light is reflected by the mirror 8 and directed to the surface 57 to uniformly illuminate the surface 57. A shutter 14 is provided near the surface 57. Reference numeral 15 is a slit that allows a part of the light flux condensed on the surface 57 to pass through.
Reference numerals 9 and 10 each denote a light condensing system including a concave mirror and the like, and uniformly illuminate a reticle (photomask 7) 16 as an illuminated surface with a light beam that has passed through the opening of the slit 15. 1
Is an illuminance sensor, which detects the luminous flux passing through the half mirror 8 and measures the illuminance on the surface 57, that is, the illuminated surface 16. Reference numeral 53 is a projection optical system (projection lens), which reduces and projects the circuit pattern on the surface of the reticle 16 onto the surface of a wafer (substrate) 54 mounted on a wafer chuck. 53a
Is the pupil plane of the projection optical system 53.

In this embodiment, the light emitting portion 2a, the second focal point 3b, and the incident surface 12a of the optical integrator 12 are used.
Are in a substantially conjugate relationship. Further, the diaphragm 12c and the pupil plane 53a of the projection optical system 53 have a substantially conjugate relationship.

In this embodiment, the pattern on the surface of the reticle 16 is reduced and projected onto the surface of the wafer 54 by the above structure. Then, a semiconductor device is manufactured through a predetermined developing process.

Reference numeral 56 denotes a differential amplifier, which is an illuminance sensor 1
Signal and a command signal from the illuminance command section 55 that outputs a signal for presetting the illuminance on the surface to be illuminated are amplified and output as a power control signal.

In this embodiment, the power control signal from the differential amplifier 56 is converted into power by the lighting device 51, and the intensity of lighting (the amount of light emission) of the light source means 2 is controlled based on the magnitude of the power. .

On the other hand, the power control signal from the differential amplifier 56 is input to the flow rate control device 52. Flow controller 52
Controls the air flowing out from the nozzle 4 based on the magnitude of the power control signal to forcibly cool the light source means 2 to prevent the temperature rise.

As described above, in the present embodiment, the light source means is forcibly cooled by using the power control signal for controlling the lighting intensity of the light source means 2, thereby eliminating the use of the temperature sensor for detecting the temperature of the light source means. The temperature of the light source means is efficiently controlled.

FIG. 2 is an enlarged explanatory view of the vicinity of the light source means 2 of FIG. The outlets of the nozzles 4a and 4b are set so as to cool the bases 19a and 19b, which are the electrode portions of the mercury lamp 2. Since the deterioration conditions of the positive electrode and the negative electrode of the mercury lamp 2 are different, the nozzles 4a and 4b are provided with throttle valves 21a and 21b so that an arbitrary flow rate can be adjusted. The flow rate control device 52 causes compressed air to flow into the throttle valves 21a and 21b. At this time, the flow rate control device 52 converts the power control signal from the differential amplifier 56 into a current signal for driving the servo valve, and the flow rate of the compressed air to the throttle valve 21 is proportional to the current signal as shown in FIG. Is being adjusted.

FIG. 4 is an enlarged explanatory view of a part of the second embodiment of the illuminating device of the present invention.

In this embodiment, three flow rate control devices, a first flow rate control unit 30, a second flow rate control unit 31, and a third flow rate control unit 32 are used. The pressure sensor 28a controls the pressure in the first flow rate control unit 30, and the flow rate is adjusted by the throttle valve 27a. The check valve 26a prevents backflow. The first flow rate control unit 30 is cooling at a certain constant flow rate regardless of whether the mercury lamp 2 is turned on or off. The second flow rate control unit 31 and the third flow rate control unit 32 include a directional control valve 29 (29b,
29c) is added, and the cooling is made variable by controlling this.

Specifically, the power control signal is compared with a preset reference signal, and the output signal thereof is used for the directional control valve 2
9b and 29c are controlled. As for the cooling method, the direction switching valve 29b of the second flow rate control unit 31 is turned on at a certain electric power value.
Then, the mercury lamp 2 is cooled at the total flow rate of the first flow rate control unit 30 and the second flow rate control unit 31. When the power value further increases, the third flow rate control unit 32 is operated at a certain power value.
Direction switching valve 29c is turned on, and the previous two units 3
The mercury lamp 2 is cooled at a flow rate of 0, 31.

FIG. 5 is an explanatory diagram showing the relationship between the electric power and the air flow rate at this time.

FIG. 6 is an enlarged explanatory view of a part of the third embodiment of the illuminating device of the present invention.

The present embodiment is greatly different from the second embodiment in FIG. 4 in that a direction switching valve 29a is added to the first flow rate control unit 30.

In this embodiment, the directional control valve 29a of the first flow control unit 30 is turned on at a certain power value, and the mercury lamp 2
Is cooling. When the electric power value further rises and reaches a certain electric power value, the directional control valve 29a of the first flow control unit 30 is turned off.
FF, and the direction switching valve 29b of the second flow rate control unit 31
Turns on. When the power value further increases, the direction switching valve 29b of the second flow rate control unit 31 turns off, and the direction switching valve 39c of the third flow rate control unit 32 turns on. The throttle valves 27a, 27b, 27c in each unit are adjusted to set the characteristic of the mercury lamp 2 to a flow rate calculated from the electric power, thereby enabling variable cooling as shown in FIG.

In contrast to FIG. 5, in FIG. 7, the cooling air flow rate can be set to 0, and since the flow rate control units can be operated in parallel, the flow rate adjustment is easier than in FIG.

Next, an embodiment of a method of manufacturing a device using the exposure apparatus described in FIG. 1 will be described.

FIG. 8 shows a flow of manufacturing a semiconductor device (semiconductor chip such as IC or LSI, or liquid crystal panel, CCD or the like).

In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. On the other hand, in step 3 (wafer manufacturing), 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 a lithography technique using the mask and the wafer prepared above.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip by using the wafer manufactured in step 4, an assembly process (dicing, bonding), a packaging process (chip encapsulation). Etc. are included. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

FIG. 9 shows a detailed flow of the wafer process.

In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in 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 exposure apparatus described above.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist peeling), the resist that has become unnecessary due to 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 difficult to manufacture in the past.

[0042]

As described above, according to the present invention, the fact that the power control signal for controlling the amount of light emitted from the light source means is substantially proportional to the temperature of the light source means is utilized, and based on the power control signal. The operation of the cooling means for cooling the light source means is controlled so that the light source means is prevented from rising above a preset temperature by a simplified control system without using a temperature sensor, and the irradiated surface is always stabilized. It is possible to achieve an illuminating device and a projection exposure apparatus using the illuminating device that can stably manufacture semiconductor devices with high accuracy and high throughput by illuminating with illuminance.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of an illumination device of the present invention and a projection exposure apparatus using the same.

FIG. 2 is an enlarged explanatory view of a part of FIG.

FIG. 3 is an explanatory diagram showing a relationship between electric power and air flow rate in the light source means of FIG.

FIG. 4 is an enlarged explanatory view of a part of a second embodiment of the illumination device and the projection exposure apparatus using the same according to the present invention.

5 is an explanatory diagram showing the relationship between electric power and air flow rate in the light source means of FIG.

FIG. 6 is an enlarged explanatory view of a part of a third embodiment of the illumination device and the projection exposure apparatus using the same according to the present invention.

7 is an explanatory view showing the relationship between the electric power and the air flow rate in the light source means of FIG.

FIG. 8 is a flowchart of a method for manufacturing a semiconductor device according to the present invention.

FIG. 9 is a flowchart of a method for manufacturing a semiconductor device of the present invention.

[Explanation of symbols]

 1 Illuminance sensor 2 Light source means 3 Elliptical mirror 4 (4a, 4b) Nozzle 5, 6, 7, 8 Mirror 11 Lens system 12 Optical integrator 13 Condensing lens 16 First object surface (reticle) 51 Lighting means 52 Lighting control means 53 Projection optical system 54 Second object plane (wafer) 55 Illuminance command unit 56 Differential amplifier

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/30 516 E 516 D

Claims (9)

[Claims] 1. When illuminating a surface to be illuminated through a lighting system with a light flux from a light source means whose light emission amount is controlled by a power control signal, the light source means is cooled by a cooling means based on the power control signal. A lighting device characterized by being forcedly cooled. 2. The light source, wherein the cooling means has a flow rate control means for controlling a flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means. The lighting device according to claim 1, wherein the means is forcibly cooled. 3. The power control signal utilizes a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. The lighting device according to claim 1, wherein the lighting device is generated. 4. When the pattern on the first object plane illuminated by the luminous flux from the illuminating means is projected onto the second object plane by the projection optical system, the illuminating means controls the light emission amount by the power control signal. The projection exposure apparatus is characterized in that the first object plane is illuminated with a light beam from the light source means through an illumination system, and the light source means is forcibly cooled by a cooling means based on the power control signal. 5. The light source, wherein the cooling means has a flow rate control means for controlling a flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means. 5. The projection exposure apparatus according to claim 4, wherein the means is forcibly cooled. 6. The power control signal utilizes a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. The projection exposure apparatus according to claim 4, wherein the projection exposure apparatus is generated. 7. When a semiconductor device is manufactured through a development processing step after projecting and exposing a pattern on a reticle surface illuminated by a light flux from an illuminating means onto a wafer surface by a projection optical system, the illumination The means illuminates the surface of the reticle with a light flux from the light source means whose power control signal controls the amount of light emission, and the cooling means forcibly cools the light source means based on the power control signal. A method for manufacturing a semiconductor device, comprising: 8. The light source, wherein the cooling means has a flow rate control means for controlling a flow rate of air and a nozzle for ejecting the air, and the air controlled by the flow rate control means is blown from the nozzle to the light source means. 8. The method for manufacturing a semiconductor device according to claim 7, wherein the means is forcibly cooled. 9. The power control signal uses a signal from an illuminance sensor that detects the illuminance on the illuminated surface and a signal from an illuminance command unit for presetting the illuminance on the illuminated surface. The semiconductor device manufacturing method according to claim 7, wherein the semiconductor device is generated.