JPH02224219A - Method of control of gap accuracy of large substrate - Google Patents

Abstract

PURPOSE:To facilitate formation of a uniform high picture quality pattern by a method wherein an adjusting means functions so as to improve a gap accuracy in accordance with the flatness of a photomask measured by a measuring means. CONSTITUTION:The flatness of a photomask 2 is measured first and an adjusting means adjusts a large substrate 1 in accordance with the measured value to cope with the warpage and deformation of the photomask 2. However, the warpage and deformation of the photomask 2 are not always regular and, further, varied from product to product. Therefore, after the state of the flatness of the photomask 2 over the whole surface is measured by a measuring means separately, the flatness of the substrate is adjusted by a flexible chuck 9 provided in the adjusting means, so that even if there is a local deformation in the photomask, the gap accuracy can be maintained steadily.

Description

[Detailed Description of the Invention] Purpose of the Invention; (Industrial Application Field) This invention aims to improve the gap accuracy between a photomask and a substrate when printing a photomask pattern onto a large substrate coated with a resist. This paper relates to a gap accuracy control method for large substrates.

(Prior Art) Normally, in order to measure the gap accuracy of a substrate, as shown in the sectional view of a gap accuracy control device using a conventional chuck in FIG. Using a gap detection sensor consisting of
The figure shows that a laser beam from a semiconductor laser 5 is incident on a photomask 2 placed on a mask frame 3, and the photomask 2 is placed on the lower surface of the photomask 2 and chuck 4. The reflected light reflected on the surface of the substrate l,
The state of reading by the line sensor 6 is shown. In this way, if a predetermined incident angle is given to the semiconductor laser 5, the gap Gl between the photomask 2 and the substrate 1 can be calculated from the corresponding reflection angle and path difference conversion at each detection point. You can ask for it. In addition, three to four locations are often selected from the outer periphery or near the four corners of the substrate l as the detection points for the gap G1, and the detection accuracy of the d111 list price is ±3.
It is managed within μfi+.

Incidentally, FIG. 14 shows the relationship between the gap amount and the shift amount of the pattern dimension in the dyeing photosensitive material, and shows that in the relationship between the gap and the image quality, as the gap becomes larger, the image quality deteriorates.

(Problem to be Solved by the Invention) When gap accuracy is managed by the method described above, for example, if we pay attention to detection points other than the selected detection points on the board 1 (within the effective screen), we find that As shown by the dotted line in Figure 13, the photomask 2 has a maximum warpage and deformation of 1100 μm due to manufacturing, but conventionally the gap Gl has been managed under conditions that ignore this. As a result, the B1 measurement is full of flaws. That is, the first
The example of the photomask 2 shown in the solid line in Figure 3 is based on the assumption of an ideal state, and in reality, the gap G in the figure is
The baking process (printing) is carried out with a gap variation of as much as 1100 μm that may occur between the substrate 1 and the photomask 2 as shown in 11. FIG. 10 shows the measurement results for the measurement positions 1 to 9 and the gap amount, and the circles indicate the conventional measurement results. In this way, the amount of variation in the conventional method is 45 μm, but since the conventional method can only adjust the gap according to the flatness of the photomask, poor flatness of the photomask directly affects the amount of variation in the gap. It has become.

In addition, in the case of the conventional method, in order to make the laser beam enter the photomask 2, a blank area with a portion of chrome removed is provided at a predetermined position on the photomask 2 as a detection window. Therefore, it has been virtually impossible to measure the gap within a filter effective pixel of, for example, a large LCD (liquid crystal) substrate.

This invention was made in view of the above-mentioned circumstances, and an object of the invention is to improve the accuracy of the printing gap on the entire surface between a large substrate and a photomask without modifying the photomask. It is an object of the present invention to provide a highly useful method for controlling the gap accuracy of a large substrate, which makes it possible to maintain a constant gap accuracy and to form a uniform high-quality pattern, and which is also applicable to multi-sided mounting.

Structure of the Invention; (Means for Solving the Problems) The present invention relates to a method for controlling the gap accuracy between a photomask and a large substrate when printing a photomask pattern onto a large substrate coated with a resist. The above object of the present invention is to provide a measuring means for measuring the flatness of the photomask and an adjusting means for adjusting the flatness of the large substrate, and to adjust the flatness measurement value of the photomask by the body side means. "C" is achieved by configuring the gap accuracy to be increased by a corresponding processing of the adjustment means based on .

(Function) This invention first measures the flatness of the photomask and adjusts the large substrate using an adjusting means based on this value in order to uniformly manage the gap accuracy related to the process of baking a photomask on a large substrate. By doing so, it is possible to deal with warpage and deformation of the photomask. However, the warpage and deformation of photomasks are not necessarily regular and vary depending on the product, so in the gap accuracy control method of the present invention, the flatness of the photomask is measured in advance using a separate measuring means. In addition, a flexible chuck installed in the adjustment means adjusts the flatness of the substrate, making it possible to maintain a constant gap accuracy even if there is local deformation of the photomask. There is. In other words, the printing process can be performed while always controlling the printing gap accuracy between the photomask and the large substrate within ±5 μm, completely avoiding the effects of warpage and deformation of the photomask.

(Example) This invention will be described in detail by giving examples below.

FIG. 2 is a sectional view of an apparatus for explaining the gap accuracy control method for large substrates according to the present invention. First, in order to measure the gap 6I between the photomask 2 placed on the mask frame 3 and the large substrate l placed on the flexible chuck 9, which serves as the point of action for flatness adjustment, the conventional method described above is used. The large substrate 1 is irradiated with laser light from the semiconductor laser 5 to three measurement points E as shown in FIG.
The light is reflected on the surface of the photomask 2 and the bottom surface of the photomask 2, and is read by the line sensor 6. A proxy aligner is used especially for large substrates.

In order to measure the flatness of the entire surface of the photomask 2, a measurement point having a window for incident light for gap measurement is determined at a predetermined position of the photomask 2.
The flatness is measured by a separate measuring means using a capacitance sensor C as shown in the flatness measuring apparatus shown in FIGS. Note that FIG. 6 shows a cross-sectional structure at DD' in FIG. 5. The capacitance sensor C measures the photomask 2 by dividing the flexible chuck 9 in FIGS. 3 and 4 when the photomask 2 is placed on the mask frame 3 of the gap quality control device shown in FIG. Measurement is performed by positioning to correspond to the piezo element P driven by an actuator provided below the area, and an example of the flatness measurement location is shown in FIG. In this example, we have described the case where a capacitance sensor is used to measure the flatness of a photomask, but instead of this, a laser beam from a semiconductor laser is irradiated onto the photomask, and this reflected light is used with a line sensor. Optical methods of detection may also be used.

In order to fixedly support the photomask 2 and the large substrate 1, the mask frame 3 and the flexible chuck 9 are provided with vacuum grooves 11 and 12 as shown in FIG. Furthermore, in order for the adjustment means to adjust the large substrate l, an actuator 10 (diaphragm, pulse motor, etc.) using a piezo element and a spring 8 arranged in parallel with the actuator 10 are fixed on the base 7 as shown in FIG. , it is sufficient if the structure is such that this is engaged with a flexible chuck 9 interposed to adjust the large substrate 1. The actuator IO pushes the flexible chuck 9 upward by piezoelectric action,
The spring 8 constantly pulls the flexible chuck 9 downward.

In this way, the precision control method for the gap between the substrate 1 and the photomask 2 can be performed, but the processing operation is
This will be explained based on the flowchart shown in the figure.

First, the flatness of the entire surface of the photomask 2 is measured as shown in Figures 5 and 6.
Step S to measure using the electrostatic container sensor C shown in the figure.
l), store this measured value in memory (step S2
). Next, gaps are measured using the conventional method described above at three gap measurement points E on the photomask 2 as shown in FIGS. 3 and 4 (step S3).
). During this measurement, the actuator 10 is driven with respect to the large substrate 1 via the flexible chuck 9 so that the gap detection accuracy regarding the gap measurement point is within ±5 μ1, which is the 8′ [capacity range], and its inclination is
Adjustment is made by the actuator drive I so that it becomes a flat surface based on measurement factors such as height (step S4). Furthermore, using the stored value of the measured value of the flatness of the photomask 2 (step S2), the flatness of the photomask 2 shown in FIG. The large substrate 1 is adjusted as shown in FIG. 2 by driving the actuator H in the region of the divided flexible chuck 9 corresponding to (step 55). The actuator IO directly converts electrical energy into linear movement.
In the gap accuracy control method of the present invention, the flexible chuck 9 that adjusts the large substrate 1 is given a fine movement amount by utilizing the drive of its piezoelectric effect. That is, based on the memorized flatness measurement value at each location of the photomask 2, the distance between the photomask 2 and the large substrate 1 is adjusted by driving each actuator in which the piezo element P is used correspondingly. The accuracy of the gap is maintained uniform through the adjustment of this adjusting means. This invention is used in the baking process of a large substrate 1, and after the gap accuracy is maintained uniform, the coordinate system processing for applying a photomask 2, photoresist, etc. to the large substrate 1 is performed. Alignment related to (
After passing through step S6), necessary printing is performed (step S7), and the printing process of the large substrate 1 is completed.

The case where the flexible chuck is divided into nine parts and driven by an actuator has been described above, and a modified example of the flexible chuck will be further described. On the bottom surface of the flexible chuck 9, crosses 7M30 and 31 as shown in FIG. 7(^) are arranged so as to intersect at the center, and an actuator is used to push the crosses 7M30 and 31 upward by piezoelectric effect as shown in FIG. 7(B). Attach 40 to section 0 in the same figure (^), and then attach it to part 0 in the same figure (8).
) As shown in Figure 4, the spring 4 always provides a downward tensile force.
By attaching 1 to the 6th part of the same figure (A), the accuracy of adjustment of flatness was improved. In addition, cross jrn 30 and 31
The cross-sectional shape of is as shown in FIG. In this case, the measurement points for the flatness measurement (step S1) of the photomask 2 were set to correspond to the actuator-driven piezo elements as shown in FIG. 11, and the number of measurement points was five. Further, as a flatness measuring device, a semiconductor laser and a line sensor as shown in FIG. 12 were used. Next, in the gap measurement between the photomask and the substrate (step S3), as shown in FIG. 7 (8), the gap measurement point E is
were set at four locations to improve gap accuracy.

However, even with such adjustment means, the non-detection portion 3 of the gap
In 2, 30 to 40μ was obtained by observing the weight of the chuck 9, etc.
There was a variation in l.

Therefore, in this invention, only a pair of diagonal cross grooves 30 are provided as shown in FIG.
As shown in 1), there are L-shaped mounting jigs 42 at the four corners and the center.
was attached, and the actuator 40 and spring 41 were coupled to the mounting jig. As a result, very highly accurate flatness as shown by the Δ mark in FIG. 10 was obtained.

In the present invention, after setting the gap between the photomask and the substrate at a predetermined measurement point (step 53
- S4), the actuator is driven according to the memorized flatness measurement value of the photomask (step S5), and the gap of the entire substrate is adjusted. According to the present invention, as described above, according to the present invention, the gap of the entire substrate may be adjusted by driving the actuator according to the memorized flatness measurement value of the photomask. We have realized a highly accurate gap accuracy control method during the printing process of large substrates that eliminates ctEu such as warping and deformation, and not only significantly improves printing efficiency and completion, but also ensures uniform gap accuracy. By managing this, it becomes possible to form high-quality patterns using the condensation method.In other words, multi-sided mounting on large substrates such as liquid crystal display substrates and color filters can be realized using a proxy aligner for large substrates. A gap accuracy control method has been realized.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an example of the processing operation of the large substrate gap accuracy control method of the present invention, FIG. 2 is a sectional view of a large substrate gap accuracy control device shown for detailed explanation of the invention, and FIG. 3 is a plan view of a flexible chuck used in the adjustment means of the present invention, FIG. 4 is a sectional view of a gap precision control device shown to explain the configuration of the adjustment means, FIG. 5 is a plan view of a photomask, and FIG. 7(8) is a cross-sectional view of an example of a photomass flatness measuring device shown at DD' in FIG. 5, FIG. 7(8) is a rear view of a flexible chuck showing an improved example of the present invention, and FIG. 8(8) is a rear view of a flexible chuck showing another embodiment of the present invention, FIG. 8(B) is a side view thereof, and FIG. 9 is a sectional view showing an example of the structure of the cross groove , FIG. 10 is a characteristic diagram showing the results of this invention in comparison with the conventional method, FIG. 11 is a diagram showing the flatness measurement points of a photomask in an improved example of this invention and another example, and FIG. A cross-sectional view showing a photomask flatness measuring device in an improved example and other embodiments of the present invention, FIG. 13 is a cross-sectional view showing a conventional substrate gap accuracy control device, and FIG. 14 is a gap amount and dimensional shift amount. FIG. DESCRIPTION OF SYMBOLS 1...Large substrate, 2...Photomask, 3...Mask frame, 4...Chuck, 5...Semiconductor laser, 6...Line sensor, 7...Base, 8...・
Spring, 9...Flexible chuck, 10...
・Actuator, 11.12...Vacuum groove. Enjoying the World's Dreams Revolutionary Team's Dreams/1st Time

Claims (1)

[Scope of Claims] 1. In a gap accuracy control method for controlling the accuracy of a gap between a photomask and a large substrate when printing a photomask pattern onto a large substrate coated with a resist, the photomask A measurement means for measuring the flatness of the photomask and an adjustment means for adjusting the flatness of the large substrate are provided, and the accuracy of the gap is adjusted by corresponding processing of the adjustment means based on the flatness measurement value of the photomask by the measurement means. 1. A method for controlling gap accuracy of a large substrate, characterized in that the method is configured to increase the gap accuracy. 2. The adjustment by the adjustment means is performed using an actuator drive through a flexible chuck, so that the overall gap accuracy between the photomask and the large substrate can be detected and managed within ±5 μm.
Gap accuracy control method for large substrates described in . 3. A cross-shaped groove is provided along the diagonal of the large substrate, and a flexible chuck consisting of an actuator and a spring is provided at each diagonal point and the center via a mounting jig. Gap accuracy control method for large substrates.