JP2007047227A - Control method for exposure in exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for exposure in an exposure apparatus that can control the exposure at low temperature without requiring countermeasure against high temperature in a conventional exposure apparatus. <P>SOLUTION: The method is characterized in that: an LED1 in a UV wavelength region is used as a light source; a forward power supply circuit 2 is used as a power supply circuit; the forward power supply circuit 2 is provided with a switching circuit 4 comprising a transistor 5 and a transistor control circuit 6; and the switching circuit 4 is controlled by pulse signals to turn on/off the forward current in a constant period per unit time to obtain appropriate exposure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for controlling an exposure amount of an exposure apparatus used for exposing a resist on a glass substrate by irradiating light to form a trimming or dividing line of the glass substrate.

  Since the conventional exposure apparatus uses an ultra-high pressure mercury lamp as a light source, the exposure amount cannot be controlled by the current ON / OFF control. This is because once the power is turned off, it is necessary to wait for a long time until the temperature of the ultra-high pressure mercury lamp decreases. Therefore, when it is desired to change the exposure amount, as shown in Non-Patent Document 1, between the ultra high pressure mercury lamp and the exposure surface, a large number of light beams can be changed or blocked in front of the ultra high pressure mercury lamp. If you want to change the exposure amount with a rotary disk called a shutter with holes of different sizes, rotate the disk with a stepping motor etc. and change the hole to match the exposure amount. . Note that a metal plate with good thermal conductivity was used for this rotating disk in order to prevent thermal deformation.

  In other words, the amount of exposure is changed by controlling the light beam reaching the exposure surface according to the size of the hole in the disk.

However, since the luminous flux emitted from the ultra-high pressure mercury lamp is constant, since the luminous flux other than the luminous flux used for exposure on the exposure surface is consumed as heat, it has become one of the causes of the exposure apparatus becoming hot. . Further, when the exposure apparatus is at a high temperature, there are very troublesome problems such as waste heat and selection of a material that can withstand the high temperature.
JP 2003-309060 A TOSCURE 251, [online], [5] Rotating shutter, [searched on August 1, 2005], Internet <URL: http: //www.harison,co,jp/pro/uv/toscure251.html>

  Therefore, an object of the present invention is to provide a method for controlling the exposure amount of an exposure apparatus that can control the exposure amount at a low temperature that does not require high temperature countermeasures, such as an exposure apparatus using a conventional ultra-high pressure mercury lamp. Is.

  The present invention has been made to solve the above-mentioned problems. The first invention uses an LED in the ultraviolet wavelength region as a light source, uses a forward power supply circuit as a power supply circuit, and uses the forward power supply. A method for controlling an exposure amount in an exposure apparatus, wherein a supply circuit is provided with a switching circuit, and the switching circuit is ON / OFF controlled by a pulse signal to change a time for irradiating an exposure surface.

  A second invention is characterized in that, in the first invention, the switching circuit is controlled by a pulse signal, the current is turned ON / OFF at a constant cycle per unit time, and the exposure time is irradiated at a constant interval. It is the exposure amount control method of the exposure apparatus which performs.

  As mentioned above, according to 1st invention, since LED of the ultraviolet wavelength region was used as a light source for exposure apparatuses, since it has little calorific value compared with the ultrahigh pressure mercury lamp used as the light source for conventional exposure apparatuses, waste heat treatment Etc. becomes easy.

  However, although the LED in the ultraviolet wavelength region used as the light source can change the light emission power by changing the current value as shown in FIG. 2, the light emission wavelength changes when the forward current changes as the LED characteristic. There is a problem.

  In general, when the forward current value is increased, the wavelength is changed to a shorter side, and in the exposure apparatus, when a resist having sensitivity to a certain wavelength is used, there is a problem that exposure cannot be performed when the wavelength is changed.

  Therefore, in the first invention, a switching circuit is provided in the forward power supply circuit, and the switching circuit is controlled by a pulse signal without changing the forward current value, and exposure per unit time on the exposure surface. Since the exposure amount is changed by changing the time, there is no problem that the exposure cannot be performed because the wavelength of the LED is not changed.

  Next, when used for the resist trimming exposure of the peripheral part of the liquid crystal substrate called a peripheral exposure apparatus, the liquid crystal substrate is allowed to pass through while irradiating the area that is the light beam emitted from the light source in order to shorten the exposure time. Exposure is in progress.

  For this reason, for example, when the illuminance per unit time is halved, the control of irradiating half the time and not irradiating the other half of the time results in overexposed and underexposed locations.

  In this regard, according to the second invention, even if the substrate moves without stopping, it is divided into, for example, 5 to 10 per unit time so that uniform illuminance can be obtained everywhere, and this is made into one cycle. The exposure amount per unit time can be changed by changing the ratio of the irradiation time and the irradiation stop time.

  For example, when a substrate speed is 40 mm / s with respect to a light beam from an exposure light source having an irradiation area of 40 mm square, an exposed portion of 40 mm is exposed in one second. When this 1 second is divided into 5 to 10 and 200 ms to 100 ms is taken as one unit, and 100 ms is taken as one unit when it is divided into 10 now, 50 ms of this 100 ms is irradiated or energized. The remaining 50 ms is turned off and not irradiated. Repeat this 10 times. By applying this to the entire surface to be exposed in one cycle, exposure with uniform illuminance with the exposure amount reduced by half is performed. It goes without saying that the ratio of reducing the exposure amount is not limited to half, and can be any ratio.

  FIG. 1 is a block diagram showing an embodiment of the present invention, where 1 is an LED in the ultraviolet wavelength region, 2 is a forward power supply circuit, 3 is a DC power supply, and 4 is a transistor provided in the forward power supply circuit 2 of the LED 1. 5, a switching circuit composed of a transistor control circuit 6, a smoothing capacitor for noise removal 7 connected in parallel with the LED 1, and a protective Zener diode 8 connected in parallel with the LED 1.

  Thus, the transistor 5 is ON / OFF controlled by the pulse signal from the transistor control circuit 6, and the transistor control circuit 6 can change the pulse width of the pulse signal and the number of pulses per unit time according to the required exposure amount. It is like that.

FIG. 2 is a graph showing the relationship between the forward current I _f (horizontal axis) flowing through the LED 1 and the relative luminous intensity (a, u) (vertical axis). The relative luminous intensity increases in proportion to the forward current.

FIG. 3 is a graph showing the relationship between the energization time t of the control pulse signal and the forward voltage _If , with the forward current set to a constant value, the energization time ON / OFF is halved, and one exposure cycle is reduced to five. This shows the case where one unit is half of the energization time, and the exposure amount is proportional to the energization time, so the exposure amount can be changed by changing the pulse width of the pulse signal or the number of pulses per unit time. You can see that

  Here, assuming that the passage speed of the substrate is 40 mm / s with respect to a light beam from an exposure light source having an irradiation area of 40 mm square, an exposed portion of 40 mm is exposed in one second. This one second is divided into 5 to 10, and 200 to 100 ms is defined as one cycle.

  Now, assuming that the passage time is divided into five as shown in FIG. 3 and 200 ms is one cycle, when it is desired to reduce the illuminance, that is, the exposure amount by half, irradiation of 100 ms out of this 200 ms, that is, LED 1 is turned on. In the remaining 100 ms, the LED 1 is turned off and is not irradiated. By repeating this five times and applying it to the entire surface of the exposed portion of the liquid crystal substrate, the exposure surface can be uniformly exposed while reducing the exposure amount by half.

  In the above example, the case where the exposure amount is reduced to half has been described. However, the rate of reduction is not limited to half, and can be arbitrarily set.

The block diagram of this invention. The graph which shows the relationship between the forward current of LED, and relative luminous intensity. The graph which shows the relationship between the forward current of LED, and energization time.

Explanation of symbols

1 LED
2 Forward current supply circuit 3 DC power supply 4 Switching circuit 5 Transistor 6 Transistor control circuit 7 Smoothing capacitor 8 Zener diode

Claims (2)

An LED in the ultraviolet wavelength region is used as a light source, and a forward power supply circuit is used as a power supply circuit. A switching circuit is provided in the forward power supply circuit, and the switching circuit is ON / OFF controlled by a pulse signal. A method for controlling an exposure amount in an exposure apparatus. 2. The exposure amount control in an exposure apparatus according to claim 1, wherein the switching circuit is controlled by a pulse signal so that the current is turned on and off at a constant cycle per unit time, and the exposure time is irradiated at a constant interval. Method.

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