KR20060128154A - Method of pattern exposure for display device fabrication - Google Patents

Abstract

A pattern exposing method for a display device is provided to reduce unexpected change of a position or width of a pattern when a screen is divided into unit intervals. An ideal pattern to be formed on a substrate is determined, and a practical pattern is formed on the basis of a unit interval to device a screen. A magnifying power to be applied to an exposure apparatus in view of sizes of the practical pattern and ideal pattern. Image information on the practical pattern and the magnifying power are input to the exposure apparatus, and light is directly irradiated on an exposure material layer formed on the substrate.

Description

Method of pattern exposure for display device {Method of pattern exposure for display device fabrication}

1 is a plan view exemplarily showing a pattern of an ideal size and shape to be formed on a substrate;

FIG. 2 is a plan view showing an actual process pattern obtained by changing the pattern of FIG. 1 so that there is no change in shape in consideration of region division by unit intervals. FIG.

FIG. 3 is a plan view showing an exposure pattern on a substrate obtained by the exposure apparatus using the actual process pattern of FIG. 2 and applying a constant correction scale. FIG.

The present invention relates to an exposure process during a display device manufacturing process, and more particularly, to a method of implementing an exposure pattern for manufacturing a display device.

Currently, the trend of screen enlargement of display devices continues, and in particular, a plasma display panel (PDP) or the like may be referred to as a display device for a large screen. In order to form a large screen, a pixel implementing device such as an electrode must be formed to form a screen on a large substrate. Usually, such a pixel implementing device is formed by a technique of processing a fine pattern to make a screen of high definition with high precision. In a display device constituting a large screen such as a PDP, the size of the pattern may be relatively large to implement the same number of pixels on the entire screen. Therefore, in the past, many printing methods that do not require a high degree of precision have been used to form partitions, electrodes, phosphors, and the like on a screen. In addition, a thick film process was used in the PDP due to the absence of an active element.

However, according to the recent trend of high definition, many exposure processes have been used to form precise patterns, and many thin film processes have also been used to form various functional films of pixels together with thick film processes.

In the exposure process, a material layer having a photochemical action such as a photoresist is applied to the target substrate on which the pattern is to be formed, and light is applied to only a portion of the pattern to be removed or a portion to be removed. In a typical exposure process, a photomask or reticle, such as a photographic plate, is placed between a light source and a material layer so that exposure to a predetermined pattern region in the material layer is performed.

However, the substrate used in the PDP is very large. When the contact mask is used in PDP manufacturing, the size of the mask to be formed for this becomes very large. In addition, in case of contact type, the mask is easily damaged and the life is short. On the other hand, in the case of using the non-contact exposure, the mask may be formed at a predetermined magnification with respect to the substrate, and the enlarged pattern image may be formed on the material layer of the substrate using an optical system made of a lens or the like. Even in this case, since the substrate is very large, the same amount of light is hardly irradiated to the central portion and the peripheral portion, and pattern distortion may occur due to the aberration of the optical system.

On the other hand, a wide substrate may be divided into several regions, such as a stepper of a semiconductor device, and divided exposure of the entire screen may be performed using the same mask by using characteristics of a display device in which a repeating pattern is continuous.

In recent years, a direct exposure (DIR) method, in which a pattern is exposed by directly irradiating a light having a limited size directly onto a material layer formed on a substrate using a screen characteristic of a display device that a simple pattern is formed over a large area, is also used. It is used. In DI exposure, laser-type point light or short line light moves to draw a pattern on a wide substrate.

When the laser beam reaches the material layer of the substrate to form a small spot size and divides the screen into a size corresponding to the size of the light spot to draw an exposure pattern, a delicate and precise pattern can be realized. However, a very large amount of time is consumed when direct exposure is performed by dividing a wide screen into such small units. Therefore, DI exposure in currently applied PDP manufacturing processes divides the substrate region horizontally and vertically, for example, at least 5 micrometers. Then, exposure is performed by discriminating whether or not to expose each divided area while moving the position where the laser beam shines.

However, in this type of DI exposure, there is a problem that the size of the pattern may be expressed when it is 5 micrometers or more. More specifically, patterns of 5 micrometers or less are ignored during exposure so that the laser beam is not split. The elements formed on the substrate are usually much larger in width of 5 micrometer beams, so it is difficult to think about the structure itself being deleted during the exposure process.

However, it can be judged that there is no part in the exposure process that should actually be present when part of the pattern is formed at that location. In this case, the width of the pattern itself may be less than the desired size, and in one aspect it may be considered that the pattern has been moved a certain distance (eg 5 micrometers) from its position. Although the spacing between patterns should be constant, there is a problem that the spacing is not constant in the above-described digital processing.

If the pattern size or spacing is not formed uniformly, the screen represented by the element having the pattern is deformed to some extent in the color or shape, resulting in a distortion phenomenon that cannot express the intended image.

In addition, although the problem is not serious in the conventional low definition definition (SD) resolution screen, a plasma display in which more element patterns should be formed based on the same screen size to realize a high definition (high definition) high definition high definition screen. In a device this problem becomes increasingly important.

The present invention provides a DI exposure method for selectively exposing an area recognized as having a pattern by dividing the screen at regular intervals as described above, and reducing the change in position or width of the pattern resulting from division at regular interval units. It is an object to provide an exposure method that can be used.

An object of the present invention is to provide an exposure method capable of reducing distortion in color and shape of an image caused by a change in a pattern while implementing a DI exposure method by screen division.

The exposure method or the exposure pattern implementation method of the present invention for achieving the above object is the first point to form a pattern based on the unit interval for dividing the screen in the pattern design step. The unit interval reference pattern thus formed is compared with the size of the pattern to be actually formed to determine an enlargement or reduction ratio (hereinafter referred to as "scale" or less). The unit interval reference pattern is input to the controller of the DI exposure apparatus in charge of exposure, and the scale is designated. The scale should be within the range possible with the corresponding DI exposure equipment, and it is desirable to determine the scale in consideration of the characteristics of the process and the characteristics of the DI exposure equipment itself.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In the present invention, first, as shown in FIG. 1, a pattern drawing having a shape that the designer considers to be ideal and a size to be formed on the substrate is formed. In this drawing, the pattern is freely determined in size or shape to a desired degree regardless of units. In Fig. 1, a horseshoe magnet-shaped pattern is formed, and the bent portion is treated with a curve. It has a total height of 110 micrometres, a total width of 108 micrometres, and a line width of 22 micrometres.

In addition, as shown in FIG. 2, a pattern drawing considering unit intervals is formed in the pattern design process. In order to form such a pattern drawing, an entire pattern is formed by reflecting line widths, spaces, marks of each kind, pitch intervals, and the like of unit patterns. Since this work is performed under the constraint of considering the unit spacing, it may be somewhat different from the shape and size of an ideal pattern as shown in FIG. 1, which the designer considers best suited for driving a panel for image realization. But. Within that limit, the most appropriate pattern form reflecting the limit, and the next pattern form from the designer's point of view, can be obtained. That is, there is a limit of 5 micrometer intervals that constrains the design, so not all patterns can have free design values and coordinate values, but they can be designed to reach the target value as much as possible.

The work of forming such a pattern can be thought of as similar to the work of forming a pattern such that each grid of grid papers having grids with unit intervals on one side is filled or emptied. Since there is no boundary of the pattern within the grid, this typically results in a pattern that is not smooth and of the most ideal size or shape. However, when the pattern is formed on the actual substrate through this operation, the pattern having the smallest shape distortion due to the screen dividing operation during exposure is obtained.

FIG. 2 shows a pattern considering unit intervals and has a form drawn on grid paper for convenience. In comparison with FIG. 1, the curved portion r is replaced by a stepped treatment portion S or a portion bent at a right angle R. As shown in FIG. For the convenience of design, the size is 100 micrometers in the left and right width, and the top and bottom height, and the pattern width is 20 micro meta.

The overall pattern considering the unit spacing of FIG. 2 and the ideal pattern size of FIG. 1 in which the pattern is actually formed on the substrate are compared to determine the enlargement or reduction ratio of the required pattern, that is, the scale. Since approximately 110 micrometers of FIG. 1 were reduced to 100 micrometers of the FIG. 2 pattern, the line width 22 micrometers was reduced to 20 micrometers. In the exposure operation, scale 1.1 is applied to the 100 micrometer pattern that will be input to the controller of the DI exposure equipment.

Although it is possible to form a pattern considering unit spacing with the size that must be formed on the substrate from the beginning, in this case, the pattern design work may be difficult due to the many factors that constrain the design. It does not need to be limited in size. However, since the scale should be able to be uniformly applied in the horizontal direction, the vertical direction, or the entire direction, the relative size or position of the width and the space in the pattern is preferably considered from the beginning. If the scale is changed for each part, the exposure of the laser beam or the like to a large area becomes too slow, so that even if the image distortion prevention effect of the present invention can be achieved, practical workability that can be modulated cannot be obtained.

The pattern drawing obtained in the pattern design step is input to a storage and adjustable part such as a controller of the exposure apparatus. The pattern diagram may be converted into digital information for input. In addition, a scale value is input to the DI exposure apparatus so as to use an adjusting device that can be adjusted for equipment calibration. This input is input to the controller along with the pattern drawing. The scale may be applied equally to the width and height, or may be input to different values in the width and height according to the function of the equipment.

When the pattern drawing and the scale value are input to the DI exposure equipment, the exposure equipment performs exposure under the direction of internal control equipment such as a controller. For example, the substrate is aligned to the substrate table, and the laser beam is selectively irradiated, depending on the region, on the material layer having the photochemical activity of the substrate through the direction and output of the controller.

Through this process, the pattern on the substrate actually formed as shown in FIG. 3 has the same shape in view of the pattern and scale (scale) of the designed pattern drawing of FIG. Although the pattern of FIG. 3 differs from the ideal pattern of FIG. 1 in shape, it is possible to prevent problems due to inadvertent changes not intended by the designer. That is, the distortion elements of the image by region division using unit intervals are excluded.

In more detail, when compared with FIG. 1, which is an ideal pattern form, the overall width and line width can obtain desired values, and the overall height is increased by 2 micrometers, but the distortion in the overall form can be avoided. If the increase in total height is a problem for the function of the pattern in advance in consideration of this in Figure 2 to adjust the overall height of the pattern to 95 micrometers. Alternatively, the scale may be set as, e.g., 1.08, or may be set as 1.1, left and right, and 1.08 in up and down within the range in which the accuracy of correction can be freely adjusted in the DI exposure equipment.

On the other hand, in determining the scale value, the size ratio between the pattern of the pattern drawing considering the unit interval and the pattern to be actually formed on the substrate is not merely an element. For example, when the barrier rib width tends to decrease when the panel substrate barrier rib of the PDP is formed through exposure, the width of the barrier rib pattern to be exposed is formed to be wider than the pattern width of the barrier rib. In this case, however, the pitch between the partition patterns must be maintained the same.

Taking the embodiment of the present invention as described above, the width of the ideal partition wall pattern is, for example, 97 micrometers.

On the other hand, if the width reduction ratio of the partition wall is approximately 10% during the firing process, the width of the partition wall pattern is formed to be 120 micrometers in the design stage to form a pattern, and the reduction ratio is 0.9 (90%). Then, in the pattern drawing, the width of the barrier rib is 120 micrometers, the width of the barrier rib pattern exposed by the scale in DI exposure equipment is 108 micrometers, and the width of the barrier rib actually obtained on the substrate through the firing process is 108 micrometers. The reduction rate is 90%, excluding 10%, which is 97.2 micrometers, giving the ideal bulkheads a 0.2-micrometer difference.

Looking back at the numerical calculations, it is assumed that the ideal bulkhead pattern width is 97 micrometers, for example. Since the reduction ratio is 10% in the firing process, X can be obtained by the inversion of the equation "X * 0.9 = 97". The value of X is 107.8 micrometers. However, assuming that it is convenient to obtain a barrier pattern drawing when calculating the pitch of the barrier rib pattern, it is possible to first obtain a size of 107.8 micrometers when the scale 0.9 is applied.

That is, 107.8 / 0.9 = 119.8 micrometers. In the design of the pattern, assuming that 5 micro meta is applied at a unit interval, 120 micrometers, which is a multiple of 5 micrometers, may be calculated as appropriate.

Therefore, when designing through this process, the width of the bulkhead pattern is set to 120 micrometers to complete the pattern drawing.

According to the present invention, in the DI exposure method for dividing the screen at regular intervals and selectively exposing an area recognized as having a pattern, unexpected change or distortion of the position or width of the pattern resulting from the division at regular intervals is prevented. It is possible to reduce the distortion in the color and shape of the image caused by the change of the pattern while implementing the DI exposure method.

Claims (7)

Determining an ideal pattern to be formed on the substrate, Forming a practical pattern based on a unit interval for dividing the screen in the pattern design step, Determining a correction magnification ratio to be applied to an exposure apparatus in consideration of the sizes of the practical pattern and the ideal pattern; And performing exposure by directly irradiating light to the exposure material layer formed on the substrate by inputting the image information and the enlargement / reduction ratio of the practical pattern into the exposure equipment. . The method of claim 1, The enlarged reduction ratio is a pattern exposure method characterized in that differently determined in the left and right and up and down directions. The method of claim 1, In determining the enlargement and reduction ratio, And further considering the characteristics of the process of forming the pattern. The method of claim 1, And further comprising a step of considering characteristics of the exposure apparatus itself forming the pattern. The method of claim 1, The laser is provided as a light source in the exposure equipment, The exposure may be carried out by applying the enlargement and reduction ratio to the utility pattern input to the exposure equipment, and irradiating the enlarged and reduced utility pattern region to the exposure material layer stacked on the substrate with the laser in a scanning manner. The pattern exposure method characterized by the above-mentioned. The method of claim 1, The unit interval is a pattern exposure method, characterized in that more than 5 micrometers. The method of claim 1, The substrate is a pattern exposure method, characterized in that the substrate of the plasma display device.

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