JP2000181075A - Lamp lighting control method in exposure apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a lamp lighting control method capable of reducing power consumption, increasing the life of a lamp, and increasing the time of performing an exposure process within the life time. SOLUTION: Exposure light emitted from a lamp 1 is collected by a condenser mirror 2.
The first plane mirror 3, the integrator lens 4,
Light irradiation device 1 through shutter 5 and collimator mirror 6
Emitted from 0. Exposure light emitted from the light irradiation device 10 is irradiated on the work through a mask (not shown) to expose the work. The lamp power supply circuit 12 for supplying power to the lamp 1 is provided with a switching circuit 12a. When performing exposure processing of a work, the rated power is input to the lamp 1 and the shutter 5 is closed to perform the exposure processing of the work. If not, the lamp will have less than rated power, for example 50 rated
Input ~ 80% power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp lighting control method in an exposure apparatus used for exposing large substrates such as a liquid crystal color filter, a PDP substrate and a printed substrate.

[0002]

2. Description of the Related Art In the production of large substrates such as liquid crystal color filters, PDP substrates, and printed substrates, an exposure step of irradiating the substrate with light containing ultraviolet rays through a mask is used. Hereinafter, the large substrate is referred to as a substrate or a work. For example, a case where the work is a liquid crystal color filter will be described. Generally, a plurality of liquid crystal color filters (hereinafter abbreviated as filters) are manufactured on one large (for example, 650 mm × 750 mm) substrate as shown in FIG. The size of the board and how many filters to make from one board depends on the size of the filter to be made.
There are many combinations. In filter manufacturing,
For example, exposure (photolithography) is used to produce a pixel pattern of a filter. In this case, there are a method of exposing the entire substrate at once, and a method of exposing the entire substrate separately for each filter to be manufactured.

When exposing the entire substrate at once, a mask having substantially the same size as the substrate is used, the mask and the substrate are aligned, and the entire substrate is irradiated with exposure light via the mask. The mask is formed with a pattern corresponding to the number of filters manufactured on one substrate. Also, when exposing separately for each filter to be manufactured,
Using a mask on which an exposure pattern corresponding to one filter is formed, aligning the mask with the first filter → exposing the first filter via the mask → moving the substrate to the second filter. Exposure is repeated for the number of filters to be used.

For example, when exposing a substrate collectively, for example, an exposure apparatus having a configuration as shown in FIG. 8 is used. In FIG. 8, exposure light emitted from a lamp 1 is condensed by a converging mirror 2, reflected by a first plane mirror 3, and incident on an integrator lens 4, whereby an illuminance distribution is made uniform.
The light emitted from the integrator lens 4 enters the collimator mirror 6 via a shutter mechanism 5 that shields the optical path, is converted into parallel light, and is emitted from the light irradiation device 10. Due to the required optical path length and dimensional restrictions of the device,
In some cases, a second plane mirror and a third plane mirror may be provided on the way. The light emitted from the light irradiation device 10 is applied to the work W mounted and fixed on the work stage WS via the mask M.

[0005] To perform the exposure processing of the work W, the work W, which is an object to be processed, is transferred by a work transfer mechanism 7 such as a work transfer robot while the shutter 5 of the light irradiation device 10 is closed. Placed and fixed on the work stage WS. A mask M on which a mask pattern is formed is arranged between the light irradiation device 10 and the work W. When the work W is placed on the work stage WS, the mask M and the work W are aligned so that the mask pattern of the mask M is exposed at a predetermined position on the work W. The alignment is performed by detecting a mask alignment mark marked on the mask M and a work alignment mark marked on the work W with the alignment microscope 8, and superposing the marks on the XYθ attached to the work stage WS. This is performed by moving the stage ST.

After the alignment is completed, the shutter 5 is opened, and the work W is irradiated with the exposure light through the mask M to expose the mask pattern on the work W. When a predetermined exposure amount is given to the work W and the exposure is completed, the shutter 5 is closed, and the work W is carried out of the work stage WS by the work transfer mechanism 7. Generally, an ultra-high pressure mercury lamp or a xenon mercury lamp that efficiently emits ultraviolet light is used as the lamp 1 provided in the light irradiation device 10. The above lamp is
It takes several minutes to several tens of minutes before the mercury in the lamp evaporates after the start of lighting and stable light is obtained. At the start of lamp lighting, a high voltage is applied to the electrodes due to dielectric breakdown, which places a heavy burden on the electrodes. If the lamp lighting start operation is performed many times, the electrodes will have adverse effects such as wear. for that reason,
Once turned on, the lamp does not go out in principle until the end of its life, but continues to be turned on at the lamp rated power. When the exposure process is not performed, the light is blocked while the lamp 1 is turned on by the mechanical light blocking means (shutter 5) as described above.

[0007]

In recent years, the size of substrates such as a liquid crystal color filter, a PDP substrate, and a printed circuit board has been increasing.
It is getting larger. Therefore, the light irradiation area (exposure area) required for the exposure apparatus used for the exposure processing is also increasing. For this reason, even if the light irradiation area is enlarged, a lamp with a higher output power is required to prevent the illuminance on the exposed surface from decreasing and the time required to obtain the required exposure amount from becoming longer and the throughput from deteriorating. . Higher power lamps consume more power. Conventionally, the light is lit at the rated power even when the exposure processing is not performed, and the power consumed at this time is useless power. Therefore, the higher the power of the lamp, the more power is wasted. On the other hand, the substrate is automatically transferred to the processing section of the exposure apparatus by a transfer robot or the like, and is unloaded from the processing section when the processing is completed. However, as the size of the substrate increases, the weight increases, and the transfer device also increases in size, so that the transfer distance of the substrate is longer than that for a small substrate.

[0008] As the substrate transport time becomes longer, the ratio of the time during which the exposure processing is not performed to the time during which the exposure processing is performed in the exposure apparatus also increases. Therefore, in addition to the wasteful power consumption described above, the time during which the exposure process is actually performed in the life time of the lamp decreases. Therefore, the cost per exposure increases.
By extending the life of the lamp, the time for performing the exposure process within the life time can be increased. However, developing a long-life lamp is not easy. The present invention has been made in view of the above circumstances, and its object is to reduce power consumption, extend the life of a lamp, and increase the time during which exposure processing is performed within the life time. It is an object of the present invention to provide a lamp lighting control method in an exposure apparatus that can perform the method.

[0009]

According to the present invention, the above objects are attained as follows. In a lamp lighting control method for an exposure apparatus that performs an exposure process on a workpiece, power input to the lamp is switched between when the exposure process is being performed on the workpiece and when the exposure process is not being performed. That is, when processing the work, the rated power is input to the lamp, and when the work is not processed, the cooling condition of the lamp is not changed and the lamp is smaller than the rated power, for example, 50 to 80% of the rated power. Input power. In the present invention, since the configuration is as described above, it is possible to reduce power consumption and extend the life of the lamp.
For this reason, it is possible to increase the time during which the exposure process is performed within the lifetime, and to reduce the cost.

[0010]

FIG. 1 is a diagram showing the configuration of a control system of a light irradiation apparatus according to an embodiment of the present invention.
Are omitted from the illustration of the mask M, the work W, the work stage WS, and the like. In FIG. 1, a light irradiation device 10 includes a lamp 1 for emitting exposure light, a condenser mirror 2,
It comprises a first plane mirror 3, an integrator lens 4, a shutter mechanism 5, and a collimator mirror 6. The light irradiation device 10 is provided with cooling means 9 for supplying cooling air to the lamp 1 and the condenser mirror 2 to cool them.

The control unit 11 includes a lamp power supply circuit 12 for supplying power to the lamp 1, a shutter controller 13 for controlling the opening and closing of the shutter 5, a cooling air controller 14 for controlling the cooling air, and an entire exposure apparatus. An exposure apparatus control unit 15 for controlling is provided. Further, the lamp power supply circuit 12 is provided with a switching circuit 12a for switching the power supplied to the lamp 1, thereby changing the lighting state of the lamp to a "full lighting state (a state in which the lamp is lit at a rated value)", a "standby lighting state". (Lamp is turned on below the rating) ". In the following, the case where the lamp is turned on at the rated value is called full lighting, and the case where the lamp is turned on at the rated value or less is called standby lighting. The lamp power supply circuit 1
2, shutter controller 13, cooling air controller 1
Reference numeral 4 is controlled by the exposure apparatus controller 15.

FIG. 2 is a diagram showing an example of the lamp cooling system. During the operation of the lamp, the temperature near the base of the lamp 1 and the condenser mirror 2 becomes high.
A cooling air is blown to the vicinity of the base from a to perform forced cooling, and the condenser mirror 2 is cooled by exhaust air. Note that FIG.
In the vicinity of the light emitting portion of the lamp envelope (hereinafter, referred to as the envelope of the lamp), it is necessary to maintain a certain temperature or higher in order to secure the amount of mercury evaporation.

FIG. 3 is a diagram showing an embodiment of the lamp power supply circuit 12. As shown in FIG. A commercial power supply is connected to the lamp power supply circuit 12, and the commercial power supply is a full-wave rectifier circuit Db, a capacitor C
1 is rectified and smoothed by the rectification / smoothing circuit 21 composed of 1. The DC voltage obtained from the rectification / smoothing circuit 21 is
It is supplied to a switching circuit 22 composed of switching elements Tr1 to Tr4. The bases of the switching elements Tr1 to Tr4 of the switching circuit 22 are connected to the output of the duty control circuit 27a, and the switching elements Tr1 to Tr4 are output by the output of the duty control circuit 27a.
Tr4 is turned on / off, and the switching circuit 22 generates a high-frequency output. The high frequency output from the switching circuit 22 is boosted by the transformer 23, and the diode D1,
It is converted to DC by a rectifying / smoothing circuit 24 composed of D2, an inductance L1, and a capacitor C2, and supplied to the lamp 1 via a power measuring circuit 25 for measuring lamp power and a starter 26 for starting lighting of the lamp 1. You.

Further, the lamp power supply circuit of the present embodiment is configured based on the power value measured by the power measurement circuit 25.
Power control circuit 2 for controlling lamp power to be constant
7 are provided. The power supply control circuit 27 includes the above-described duty control circuit 27a, a comparator 27b that compares a lamp power value measured by the power measurement circuit 25 with a reference power value and outputs a comparison signal, and a switching circuit 12a. The duty control circuit 27a outputs a duty signal according to the comparison signal from the comparator 27b. Also,
The switching circuit 12a includes a standby lighting reference power value generator 27.
d, a full lighting reference power value generator 27e, and the generator 2
Power switch 27 for switching outputs of 7d and 27e
c.

To switch between full lighting and standby lighting, the power switch 27c of the switching circuit 12a is switched, and the "standby lighting reference power value" or the full lighting reference power value output from the standby lighting reference power generator 27d. "Full lighting reference power value" output from the generator 27e
To the comparator 27b. The comparator 27b compares the lamp power measured by the power measuring circuit 25 with the “standby lighting reference power value” or the “full lighting reference power value”, and outputs a comparison signal according to the difference. The duty control circuit 27a switches the switching elements Tr1 to T1 according to the comparison signal.
Change the duty of r4. Thereby, the lighting state of the lamp 1 can be switched between the “full lighting state” and the “standby lighting state”.

The power switch 27c is switched by a signal from the exposure apparatus controller 15. As will be described later, for example, in the case of batch exposure, switching is performed in synchronization with the opening / closing operation of the shutter, and in the case of divided exposure, switching is performed in synchronization with the end of alignment between the mask and the work and the completion of exposure of the entire area of the work. Note that a manual control switch may be provided on a control panel of a power supply (not shown) so as to be manually switched.

Next, a description will be given of the lamp lighting control of the present embodiment in the case where the work is exposed all at once and the case where the work is dividedly exposed. (1) In the case where the entire surface of the work is exposed collectively In the exposure apparatus shown in FIGS. 1 and 8, when the entire surface of the work is exposed collectively, the lighting of the lamp is controlled as follows. FIG. 4 is a diagram showing the relationship between the switching of the lamp input power and the opening / closing operation of the shutter 5 in the batch exposure, and in the figure correspond to the following circled numbers. No work W on work stage WS, shutter 5
Also, when the exposure light is not emitted from the light irradiation device 10 by closing the lamp 1, the lamp 1 is turned on in standby with, for example, 70% of the rated power (FIG. 4). Light from lamp 1 is shutter 5
, And no exposure light is emitted from the light irradiation device 10. The work W before the processing is
Is carried into the work stage WS. Next, the alignment microscope 8 detects the mask alignment mark marked on the mask M and the work alignment mark marked on the work W, and aligns the mask M with the work W.

Next, an exposure process is performed. Before the shutter 5 is opened, the exposure device controller 15 controls the lamp power supply circuit 12.
Power switch 27c of switching circuit 12a provided in
(See FIG. 3), and the lamp 1 is switched from the standby lighting to the full lighting which is the rated lighting state (FIG. 4). This is because it takes about 0.5 seconds for the illuminance to rise to the predetermined value at which the rating has been input when the power is switched from 70% of the rating to the rating. That is, if the power is switched at the same time as when the shutter is closed, the work cannot be exposed with a predetermined illuminance at the beginning of the exposure.

The shutter 5 is opened by the shutter controller 13, and exposure light is emitted from the light irradiation device 10.
The work W is irradiated with exposure light through the mask M to expose the work W
Are exposed collectively. The exposure time is 1 to 5 seconds (FIG. 4). After the exposure processing, the shutter controller 13 closes the shutter 5, switches the power switch 27c of the switching circuit 12a, and switches the lamp 1 to standby lighting (FIG. 4). Next, the work W after the exposure processing is carried out from the work stage WS, and the unexposed work is carried in. The time required for “unloading the exposed work from the work stage → loading in the work before the exposure processing → positioning of the mask and the work” is about 20 seconds. Therefore, “full lighting 1 to 5 seconds → standby lighting 20 seconds” is repeated.

(2) In the case of an apparatus that divides a substrate and exposes it. In the exposure apparatus shown in FIGS. 1 and 8, when the work is divided and exposed, the lighting of the lamp is controlled as follows. FIG. 5 is a diagram showing the relationship between the switching of the lamp input power and the opening / closing operation of the shutter 5 in the divided exposure. In FIG. 5, 〜 corresponds to the following circled numbers. As in the case of the batch exposure, when there is no work W on the work stage WS, the shutter 5 is closed and the exposure light is not emitted from the light irradiation device 10, the lamp 1 is turned on by standby at, for example, 70% of the rated power. (Of FIG. 5). While the lamp 1 is in the standby lighting state, the work W is carried into the work stage WS by the work transfer means 7, and the divided exposure area of the work 1 and the mask M are aligned by the alignment microscope 8 as described above.

The exposure apparatus control unit 15 switches the power switch 27c (see FIG. 3) of the switching circuit 12a provided in the lamp power supply circuit 12, and switches the lamp 1 from standby lighting to full lighting, which is a rated lighting state ( FIG. 5). The shutter controller 13 opens the shutter 5, emits exposure light from the light irradiation device 10, irradiates the work W with the exposure light via the mask M, and exposes a predetermined area of the work W. The exposure time is 1-2 seconds (FIG. 5). After the exposure processing, the shutter 5 is closed, and the work stage WS is moved so that the next exposure area can be exposed.
When the work W reaches the next exposure area, the mask M and the work W are aligned as described above. The time required for this movement and alignment is 1-2 seconds. During this time, the lamp power is not switched (FIG. 5). When the lamp power is switched at intervals of 1 to 2 seconds, the electrodes are easily worn, and the life of the lamp 1 is rather shortened.

After the alignment, the shutter 5 is opened to expose a predetermined area (FIG. 5). This is repeated for the number of divisions. When exposure processing is completed for all exposure areas,
The shutter controller 13 closes the shutter 5, and
The switching circuit 12a provided in the lamp power supply circuit 12 is switched to switch the lamp 1 to standby lighting. The work W after the exposure processing is carried out from the work stage WS,
The unexposed work W is carried in. The time required for unloading the processed work W → loading in the unprocessed work W → positioning of the mask M and the first area of the work W is about 20 seconds as in the case of the batch exposure. Therefore, "full lighting several seconds to several tens of seconds (depending on the number of filters manufactured from one substrate)
→ Standby lighting for 20 seconds "is repeated.

In the above embodiment, the lamp power in the standby lighting state is set to 70% of the rated value, for the following reason. When the initial illuminance of the lamp is reduced to 100% and the illuminance is reduced to 70%, the lamp life is defined. When the lamp with a rated input power of 8 kW is continuously lit at the rated power, the life time is defined as 1. Electric power (8k
The total life time when lighting at W) and lighting at 70% (5.6 kW) of the rating were alternately repeated every minute was examined. As a result, the life time became 1.4 as shown in FIG. In FIG. 6, the vertical axis indicates the irradiance of the lamp when the initial illuminance is 100%, the horizontal axis indicates the lighting time ratio when the lamp life is 1, and a indicates the case where the lamp is continuously lit at the rated power. And b is the illuminance change when lighting with the rated power and lighting with 70% of the rated power are alternately repeated every minute. As is clear from the results in FIG. 6, when the lamp power in the standby lighting state is set to 70% of the rated value, the lamp life becomes 1.4 times, and the lamp life can be extended.

The lamp power for standby lighting is not limited to 70% of the rated value. That is, in the light irradiating device as the light source unit, when the lamp is turned on as shown in FIG. 2, the condenser mirror is forcibly cooled by blowing the cooling air by blowing the cooling air by the exhaust air. On the other hand, the sealing body near the light emitting portion of the lamp needs to be maintained at a certain temperature or higher as described above. Therefore, if the lamp power during standby lighting is too small when the cooling amount is large, the lamp cannot be stably turned on.However, if the cooling amount is small, even if the lamp power during standby lighting is reduced, The lighting of the lamp can be maintained. For this reason,
It is desirable that the lamp power for standby lighting be set as appropriate by measuring the cooling conditions of the light irradiation device and the sealing temperature of the lamp.

As a result of measurement with various lamps and a light irradiation device, the lamp enclosure can be maintained at an appropriate temperature without changing the cooling conditions when the lamp is fully lit, and the life of the lamp can be extended. It was found that the lamp power at the time of standby at which the power consumption can be achieved was 50 to 80% of the rated power. If the cooling condition of the lamp is changed between full lighting and standby lighting, the range of lamp power during standby can be further widened. However, since the control of the cooling air volume is required, the control system becomes complicated.

[0026]

As described above, in the present invention,
The following effects can be obtained. (1) In an exposure apparatus used for exposing a large-sized liquid crystal substrate, when the exposure apparatus is not performing an exposure process such as unloading and loading of a work and alignment of a mask and a work, the input of a lamp is set to be smaller than a rated power. Since the lamp is turned on to extend the total lamp life, the cost per exposure can be reduced. (2) The power consumption of the device can be reduced,
Power can be saved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a control system of a light irradiation device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a lamp cooling system.

FIG. 3 is a diagram showing an embodiment of a lamp power supply circuit.

FIG. 4 is a diagram illustrating a relationship between switching of lamp input power and opening and closing operations of a shutter in a batch exposure.

FIG. 5 is a diagram showing a relationship between switching of lamp input power and opening and closing operations of a shutter in divided exposure.

FIG. 6 is a diagram showing the relationship between the lighting time of the lamp and the irradiance of the lamp.

FIG. 7 is a diagram illustrating an example of a liquid crystal color filter.

FIG. 8 is a diagram showing a configuration of an exposure apparatus to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 lamp 2 condenser mirror 3 first plane mirror 4 integrator lens 5 shutter 6 collimator mirror 9 cooling means 9a cooling nozzle 10 light irradiation device 11 control unit 12 lamp power supply circuit 12a switching circuit 13 shutter controller 14 cooling air controller 15 exposure device control unit DESCRIPTION OF SYMBOLS 21 Rectifier / smoothing circuit 22 Switching circuit 23 Transformer 24 Rectifier / smoothing circuit 25 Power measurement circuit 26 Starter 27 Power control circuit 27a Duty control circuit 27b Comparator 27c Power switch 27d Standby lighting reference power value generator 27e Full lighting reference power value Generator

Claims (1)

[Claims] 1. A method for controlling a lighting power of a lamp in an exposure apparatus used for exposing a large-sized substrate, comprising: exposing a substrate as a work, carrying out a processed work from an exposure processing unit, and exposing an unprocessed work. Loading into the department,
And a lamp lighting control method in the exposure apparatus, wherein the lamp is turned on while the power input to the lamp is smaller than the rated power while the work is being aligned in the exposure processing section.