KR20000057050A - A method for controlling lamp used in an exposing apparatus - Google Patents

Abstract

PURPOSE: Control method of lamp ignition on photo exposure unit is provided to decrease the power consumption and to improve the longer life of lamp. CONSTITUTION: Control method of lamp ignition on photo exposure unit comprising; the photo exposure light from a lamp(1) are collected on a photo collecting mirror(2), and via 1st plane mirror(3), integrator lens(4), shutter(5), time standard mirror(6), photographing visit out from a photo irradiation unit(10); the photo exposure light from the photo irradiation unit(10) through mask to a work. and photo exposured. a shift circuit(12a) is installed on a lamp power source circuit(12), and a constant normal power input to the lamp(1), a 50-80% power of the normal power is input to the lamp when shutter(5) is closed.

Description

A method for controlling lamp used in an exposing apparatus}

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 exposure processing of large substrates such as liquid crystal color filters, PDP substrates, and printed substrates.

In the manufacture of large substrates such as liquid crystal color filters, PDP substrates, and printed substrates, an exposure process of irradiating light containing ultraviolet rays to the substrate through a mask is used. Hereinafter, those of the large substrate are referred to as substrates or workpieces.

For example, the case where a workpiece | work is a liquid crystal color filter is demonstrated.

In general, a plurality of liquid crystal color filters (hereinafter abbreviated as filters) are produced on a single large substrate (for example, 650 mm x 750 mm) as shown in FIG.

There are many combinations of the size of the substrate and how many filters are made from one substrate, depending on the size and the filter to be produced.

In filter manufacture, exposure (photolithography) is used, for example in order to produce the pixel pattern of a filter. In that case, there are a method of exposing the entire substrate in a batch and a method of dividing and exposing each filter to be produced.

In the case of exposing the whole substrate collectively, the mask and the substrate are aligned by using a mask almost the same size as the substrate, and the exposure light is irradiated on the entire substrate through the mask. As many masks are formed in the mask as the number of filters fabricated on one substrate.

When dividing and exposing each filter to be produced, using a mask in which an exposure pattern corresponding to one filter is made, the mask is aligned with the first filter → the exposure of the first filter → the second filter through the mask. It exposes repeatedly by the number of sheets of the filter which produce the movement of the board | substrate.

For example, when exposing a board | substrate collectively, the exposure apparatus of the structure as shown, for example in FIG. 8 is used.

In FIG. 8, the exposure light emitted by the lamp 1 is collected by the light converging mirror 2, reflected by the first planar mirror 3, and incident on the integrator lens 4 to uniform the illuminance distribution. The light emitted from the integrator lens 4 enters the collimator mirror 6 through the shutter mechanism 5 that shields the optical path, becomes parallel light, and exits from the light irradiation apparatus 10. Moreover, a 2nd planar mirror and a 3rd planar mirror may be provided along the way depending on the required optical path length and the dimension of the apparatus.

The light emitted from the light irradiation apparatus 10 is irradiated to the work W mounted and fixed on the work stage WS through the mask M. As shown in FIG.

To perform the exposure treatment of the workpiece W, the workpiece W, which is an object to be processed, is transported by a workpiece transport mechanism 7 such as a robot for transporting the workpiece while the shutter 5 of the light irradiation apparatus 10 is closed. It is mounted and fixed to the work stage WS.

Between the light irradiation apparatus 10 and the workpiece | work W, the mask M in which the mask pattern was formed is arrange | positioned.

When the workpiece W is placed on the work stage WS, the mask M and the workpiece W are aligned so that the mask pattern of the mask M is exposed at a predetermined position of the workpiece W. FIG. The alignment is performed by detecting the mask alignment mark displayed on the mask M and the workpiece alignment mark displayed on the workpiece W by the alignment microscope 8, and the XYθ stage ST mounted on the work stage WS so that the marks overlap with each other. Move it).

After the alignment is completed, the shutter 5 is opened and the exposure light is irradiated onto the work W through the mask M to condense the mask pattern onto the work W. FIG. When a predetermined exposure amount is given to the workpiece W and the exposure is completed, the shutter 5 is closed and the workpiece W is carried out from the work stage WS by the workpiece transport mechanism 7.

As the lamp 1 provided in the light irradiation apparatus 10, the ultra-high pressure mercury lamp and xenon mercury lamp which generally emit ultraviolet light efficiently are used.

The lamp needs several minutes to several tens of minutes until mercury in the lamp evaporates to obtain stable light after the lamp is started. In addition, since the high voltage is applied to the electrode for insulation breakdown at the start of lamp lighting, the electrode is burdened, and if the lamp lighting start operation is performed several times, it adversely affects the wear or the like. For this reason, once lit, the lamp does not turn off in principle until the life time is reached, but continues to be lit at the rated power of the lamp. When the exposure process is not performed, light shielding is performed while the lamp 1 is turned on by the mechanical light shielding means (shutter 5) as described above.

In recent years, the size of substrates, such as a liquid crystal color filter, a PDP board | substrate, and a printed circuit board, is enlarged. Therefore, the light irradiation area (exposure area) required for the exposure apparatus used for an exposure process is also expanding.

Therefore, even if the light irradiation area is enlarged, a lamp of higher output is required in order to prevent the illuminance of the exposure surface from decreasing and the time for obtaining the required exposure amount becomes longer or the yield is deteriorated. Higher power lamps consume more power.

Conventionally, even when the exposure process is not performed, the lamp is turned on at the rated power, and power consumed at this time is unnecessary power. Therefore, the higher the lamp, the more power is consumed in vain.

On the other hand, a board | substrate is automatically conveyed to the process part of an exposure apparatus by a conveyance robot etc., and is carried out from a process part when a process is complete | finished. However, when the substrate is enlarged, the weight is increased, and the conveying apparatus is also enlarged, and the conveyance distance of the substrate is longer than that for the small substrate.

When the substrate transfer time is long, the ratio of the time of not performing exposure processing to the time of performing exposure processing in the exposure apparatus also increases.

Therefore, the above-described wasteful power increases, and the time during which the exposure is actually performed is reduced in the life time of the lamp. Therefore, the cost per exposure increases.

The longer life of the lamp can increase the time of performing the exposure treatment within the life time. However, it is not easy to develop a lamp of long life.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a lamp lighting in an exposure apparatus capable of reducing the power consumption and extending the life of the lamp to increase the time for performing exposure processing within the life time. It is to provide a control method.

1 is a diagram showing the configuration of a control system of a light irradiation apparatus according to an embodiment of the present invention;

2 is a view showing an example of a lamp cooling system;

3 shows an embodiment of a lamp power circuit;

4 is a diagram showing a relationship between switching of lamp input power and opening / closing operation of a shutter in batch exposure;

Fig. 5 is a diagram showing a relationship between switching of input power and opening / closing operation of a circuit in split exposure;

6 is a view showing a relationship between the lamp lighting time and the irradiance of the lamp;

7 is a view showing an example of a liquid crystal color filter;

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

(Explanation of the sign)

1: lamp 2: condenser

1: First flat mirror 4: Integrator lens

5: shutter 6: collimation mirror

9 cooling means 9a cooling nozzle

10: light irradiation device 11: control unit

12 lamp power circuit 12a switching circuit

13: shutter controller 14: cooling wind controller

15: exposure apparatus controller 21: rectification and smoothing circuit

22: switching circuit 23: transformer

24: rectification and smoothing circuit 25: power measurement circuit

26: starter 27: power control circuit

27a: duty control circuit 27b: comparator

27c: power changeover switch 27d: standby light reference power value generator

27e: full-power reference generator

The present invention solves the following problems.

In the lamp lighting control method of the exposure apparatus which performs the exposure process of a workpiece | work, the power input to a lamp is switched when the workpiece is exposed and the exposure process is not performed. That is, when the workpiece is processed, the rated power is input to the lamp. When the workpiece is not processed, the lamp has a power smaller than the rated power, for example, 50 to 80% of the rated power so as not to change the cooling conditions of the lamp. Enter it.

In the present invention, the configuration as described above can reduce the power consumption and extend the life of the lamp. For this reason, the time to perform exposure processing within a lifetime can be increased, and cost reduction can be aimed at.

1 is a diagram showing the configuration of a control system of a light irradiation apparatus according to an embodiment of the present invention, in which the mask M, the work W, the work stage WS, and the like shown in FIG. 8 are omitted. .

In FIG. 1, the light irradiation apparatus 10 includes a lamp 1, a light collecting mirror 2, a first planar mirror 3, an integrator lens 4, a shutter mechanism 5, which emits exposure light as described above. It consists of a collimation mirror 6. Moreover, the light irradiation apparatus 10 is provided with the cooling means 9 which supplies cooling air to the lamp 1 and the condenser 2, and cools them.

The control unit 11 includes a lamp power supply circuit 12 for supplying electric power to the lamp 1, a shutter controller 13 for controlling opening and closing of the shutter 5, a cooling wind controller 14 for controlling the cooling wind, and An exposure apparatus control unit 15 for controlling the entire exposure apparatus is provided. In addition, a switching circuit 12a for switching the power supplied to the lamp 1 is provided in the lamp power supply circuit 12, whereby the lighting state of the lamp is " full lighting state (state in which the lamp is lit at rated). Switch to the standby standby state (state in which the lamp is turned on below the rated value). In the following description, the case where the lamp is lit at the rated value is referred to as full lighting, and the case where the lamp is lit below the rated temperature is called standby lighting.

The lamp power supply circuit 12, the shutter controller 13, and the cooling wind controller 14 are controlled by the exposure apparatus control unit 15.

2 is a diagram illustrating an example of the lamp cooling system. During lamp lighting, since the vicinity of the cap of the lamp 1 and the condenser 2 become high temperatures, as shown in the figure, cooling air is blown out from the cooling nozzle 9a to the vicinity of the cap, forcibly cooled, The condenser 2 is cooled by blowing wind. In addition, in the vicinity of the light emitting portion of the lamp rod (shown as a glass container of the lamp, hereinafter referred to as a rod) shown in Fig. 2, it is necessary to maintain it above a predetermined temperature in order to secure the evaporation amount of mercury.

3 shows an embodiment of the lamp power supply circuit 12. As shown in FIG.

The commercial power supply is connected to the lamp power supply circuit 12, and the commercial power supply is rectified and smoothed by the rectifying and smoothing circuit 21 composed of the full-wave rectifying circuit Db and the condenser C1. The DC voltage obtained from the rectification and smoothing circuit 21 is supplied to the switching circuit 22 comprised of the 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 turned on / off by the output of the duty control circuit 27a. OFF to generate a high frequency output from the switching circuit 22. The high frequency output from the switching circuit 22 is boosted by the transformer 23 and switched to direct current by the rectification and smoothing circuit 24 composed of diodes D1 and D2, inductance L1, and capacitor C2. The lamp 1 is supplied to the lamp 1 through a power measurement circuit 25 for measuring lamp power and a starter 26 for starting the lamp 1 to be turned on.

The lamp power supply circuit of this embodiment is provided with a power supply control circuit 27 for controlling the lamp power to be constant according to the power value measured by the power measurement circuit 25.

The power supply control circuit 27 includes a comparator 27b and a switching circuit 12a which output a comparison signal by comparing the lamp power value measured by the duty control circuit 27a and the power measurement circuit 25 with the reference power value. Is provided, and the duty control circuit 27a outputs a duty signal corresponding to the comparison signal from the comparator 27b. The switching circuit 12a includes a standby lighting reference power value generator 27d, a full lighting reference power value generator 27e, and a power switching switch 27c for switching the outputs of the generators 27d and 27e. .

To switch between full and standby lights, the standby light reference power value generator 27d outputs the standby light reference power value generator 27d or the full light reference for switching the power switching switch 27c of the switching circuit 12a. The "full lighting reference power value" output from the power value generator 27e is given to the comparator 27b.

The comparator 27b compares the lamp power measured by the power measurement circuit 25 with the "standby reference reference power value" or "full lamp reference power value" and outputs a comparison signal according to the difference. The duty control circuit 27a changes the duty of the switching elements Tr1 to TR4 in accordance with the comparison signal. Thereby, the lighting state of the lamp 1 can be switched to "full lighting state" and "waiting lighting state".

The power switching switch 27c is switched in accordance with a signal from the exposure apparatus control unit 15. As described later, for example, in the case of package exposure, switching is performed in synchronization with the opening and closing operation of the shutter, and in the case of split exposure, the switching is performed in synchronization with the end of alignment of the mask and the work and the end of exposure of the entire area of the work. Moreover, you may install as a manual switch in the control panel of the power supply which is not shown in figure, and may change it manually.

Next, the lamp lighting control of the present embodiment will be described with respect to the case where the workpieces are collectively exposed and the case where the workpieces are dividedly exposed.

(1) When collectively exposing the entire surface of the work

In the exposure apparatus shown in FIG. 1 and FIG. 8, when collectively exposing the whole surface of a workpiece | work, lighting of a lamp is controlled as follows.

Fig. 4 is a diagram showing the relationship between switching the lamp input power in the collective exposure and opening / closing operation of the shutter 5, and 1 to 4 in the figure correspond to the following numerals.

(1) When there is no workpiece W in the work stage WS and the shutter 5 is closed and no exposure light is emitted from the light irradiation apparatus 10, the lamp 1 is operated at 70% of the rated power, for example. The atmosphere is turned on (1 in FIG. 4). Light from the lamp 1 is shielded by the shutter 5 so that the exposure light is not emitted from the light irradiation apparatus 10. The workpiece W is carried into the workpiece stage WS by the workpiece conveying means 7. Subsequently, the mask alignment mark displayed on the mask M and the work alignment mark displayed on the work W are detected by the alignment microscope 8, and the mask M and the work W are aligned.

(2) The exposure processing is performed next. Before the shutter 5 is opened, the power switching switch 27c (see Fig. 3) of the switching circuit 12a provided in the lamp power supply circuit 12 is opened by the exposure apparatus control unit 15. The lamp 1 is switched from the standby lamp to the full lamp of the rated lighting state (2 in Fig. 4).

This is because it takes about 0.5 seconds for the illuminance to rise to the predetermined value at which the rating is entered when the power is switched from the 70% input of the rating to the rating. That is, by switching power at the same time as closing the shutter, the workpiece cannot be exposed to a predetermined illuminance at the beginning of exposure.

(3) The shutter 5 is opened by the shutter controller 13, the exposure light is emitted from the light irradiation apparatus 10, the exposure light is irradiated onto the work W through the mask M, and the work W is collectively collected. It exposes. The exposure time is 1 to 5 seconds (3 in Fig. 4).

(4) After the end of the exposure process, the shutter controller 13 closes the shutter 5 and at the same time switches the power switching switch 27c of the switching circuit 12a to switch the lamp 1 to atmospheric lighting (Fig. 4). ④).

Next, the workpiece | work W which the exposure process is complete is taken out from the work stage WS, and the unexposed workpiece is carried in. The time taken for "exporting from the work stage of exposure end work → import of the workpiece before exposure process → alignment of a mask and a workpiece | work" is about 20 second.

Therefore, "full lighting 1-5 second-20 second waiting light" is repeated.

(2) In the case of an apparatus which divides and exposes a board | substrate.

In the exposure apparatus shown in FIG. 1 and FIG. 8, when dividing a workpiece | work and exposing, the lighting of a lamp is controlled as follows. Fig. 5 is a diagram showing the relationship between switching of the lamp input power in the divided exposure light and opening / closing operation of the shutter 5, and 1 to 4 in the same time correspond to the following original numerals.

(1) When the workpiece stage (W) does not have a workpiece (W) and the shutter (5) is closed and no exposure light is emitted from the light irradiation apparatus (10), the lamp 1 is taken as an example. For example, the lamp is turned on at the power of 70% of the rating (1 in Fig. 5). The lamp 1 carries the workpiece | work W into the workpiece | work stage WS by the workpiece conveyance means 7 in the state of a waiting light, and divided | segmented the workpiece | work 1 by the alignment microscope 8 as mentioned above. The exposure area and the mask M are aligned.

(2) The electric power switching switch 27c (see Fig. 3) of the switching circuit 12a provided in the lamp power supply circuit 12 is switched by the exposure apparatus control unit 15, so that the lamp 1 is turned on from the standby light at a rated lighting state. It switches to phosphorus pull lighting (2 in FIG. 5).

(3) The shutter controller 13 opens the shutter 5, emits the exposure light from the light irradiation apparatus 10, irradiates the exposure light to the work W through the mask M, and the predetermined value of the work W. The area is exposed. The exposure time is 1 to 2 seconds (3 in Fig. 5).

(4) After the end of the exposure process, the shutter 5 is closed and the work stage WS is moved to expose the next exposure area. When the workpiece W reaches the next exposure area, the mask M and the workpiece W are aligned as described above. The time required for this movement and alignment is 1-2 seconds. In the meantime, switching of the lamp power is not performed (4 in Fig. 5). This is because when the lamp power is switched at intervals of 1 to 2 seconds, the electrodes are easily worn and the lamp 1 is shortened.

(5) After the positioning is completed, the shutter 5 is opened to expose a predetermined area (5 in FIG. 5). Repeat this for the number of divisions.

(6) When the exposure process is finished for all exposure areas, the shutter controller 13 closes the shutter 5, switches the switching circuit 12a provided in the lamp power supply circuit 12, and turns the lamp 1 to the standby light. Switch.

The workpiece | work W which the exposure process is complete is carried out from the workpiece | work stage WS, and the unexposed workpiece | work W is carried in. The time required for taking out the processing end work W → bringing in the work W before processing → alignment of the first area of the mask M and the work W is about 20 seconds as in the case of the batch exposure described above. .

Therefore, "full lighting several seconds-several tens of seconds (by the number of filters manufactured by one board | substrate)-> 20 seconds of waiting lighting" is repeated.

In the above embodiment, the lamp power in the standby light state was 70% of the rating, 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 assumed.When the lamp has a constant input power of 8 kW and the lifetime is set to 1 when the continuous lighting is performed at the rated power, The total life time when the lighting at rated power (8 kW) and the lighting at 70% (5.6 kW) of rating were alternately repeated every minute was investigated. As a result, the life time became 1.4 as shown in FIG.

In Fig. 6, the vertical axis represents the irradiance of the lamp when the initial illuminance is 100%, the horizontal axis represents the lighting time ratio when the lamp life is 1, and a is the illuminance change when continuous lighting is performed at the rated power. Is the change in illuminance when the lighting by rated power and the lighting by 70% of rated power are alternately repeated every minute.

As can be seen from the result of Fig. 6, when the lamp power in the standby light state is 70% of the rating, the lamp life becomes 1.4 times and the life of the lamp can be extended.

The lamp power of the standby lamp is not limited to 70% of the rating. That is, in the light irradiation apparatus as the light source unit, as shown in FIG. 2, when the lamp is turned on, the condenser is blown out by the wind, and the cap portion of the lamp emits cooling wind to force cooling. On the other hand, it is necessary to keep the rod body near the light emitting portion of the lamp above a predetermined temperature as described above.

Therefore, when the amount of cooling is large, the lamp cannot be stably lit if the lamp power at the time of standby lighting is made too small. However, when the amount of cooling is small, the lamp can be maintained even if the lamp power at the time of standby lighting is reduced. For this reason, it is preferable to set the lamp power of an atmospheric lamp suitably by measuring the cooling conditions of a light irradiation apparatus, and the sealing body temperature of a lamp.

As a result of measurements made by various lamps and light irradiation devices, lamp lamps can be kept at an appropriate temperature without changing the cooling conditions when the lamps are fully lit, and the lamp power in standby can be extended to life. Was found to be 50-80% of the rated power.

In addition, if the cooling conditions of the lamp are changed to at the time of full lighting and at the time of standby lighting, it is also possible to widen the range of lamp power at the time of standby. However, since the control of the cooling air amount is required, the control system is complicated.

As described above, in the present invention, the following effects can be obtained.

(1) In an exposure apparatus used for exposure of a large liquid crystal substrate, when the exposure apparatus is not subjected to exposure processing such as carrying out and carrying in a workpiece, or aligning a mask with the workpiece, the lamp input is made smaller than the rated power and turned on to Since the lamp life is extended, the cost per exposure can be reduced.

(2) The power consumption of the device can be reduced, and the power can be saved.

Claims (1)

In the lighting power control method of the lamp in the exposure apparatus used for the exposure of a large substrate, After the exposure process of the substrate which is a work, the power input to the lamp is greater than the rated power while being carried out from the exposure processing unit of the finished workpiece, brought into the exposure processing unit of the unprocessed work, and alignment of the work in the exposure processing unit. The lamp lighting control method in the exposure apparatus characterized by lighting in a small state.