JPH05142746A - Method for forming pattern plate having alignment pattern and pattern plate formed by the method - Google Patents

Abstract

PURPOSE:To form the pattern plate which has alignment patterns with small distortion of a main pattern so the position relation between the alignment pattern and main pattern is precise. CONSTITUTION:When the pattern plate which has the main pattern B such as a reticle pattern, a shadow pattern, etc., and the alignment patterns A1, A2, and A3 is formed, the alignment patterns A1, A2, and A3 of a final product are previously formed on a substrate 1 and then the positions of the alignment patterns A1, A2, and A3 of the substrate 1 are read; while the relative positions of the patterns with a pattern forming beam are controlled, the main pattern B is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a pattern plate having an alignment pattern (mark) for alignment, and more particularly to a reticle mask and a shadow for projecting a pattern on a wafer or a master mask substrate. The present invention relates to a method for drawing a large-sized pattern plate used for a mask or the like and a pattern plate drawn by the method.

[0002]

2. Description of the Related Art In recent years, ICs and LSIs have become more highly integrated, and 4 Mbit DRAMs have already entered the mass production stage, and are shifting to 16 Mbits and 64 Mbits. Along with this, further miniaturization of circuit elements on the wafer is required, and miniaturization is also required for pattern formation by the lithographic technique for producing circuit elements on the wafer. ..

There are usually the following three methods for forming a pattern on a wafer. The first method is a method using an EB (electron beam) apparatus or an FIB (focused ion beam) apparatus, in which the electron beam or the ion beam is controlled to directly form a pattern on the wafer. In this case, since the drawing position is controlled according to the pattern on the wafer, the patterning accuracy depends only on the position detection ability and the drawing position control ability. And, some problems still remain in the position detection ability and the position control ability. This method
Since the pattern is created one by one, it takes a lot of time for drawing, so it is not suitable for mass production. The second method is
It is a method of transferring this to a wafer substrate by using a mask that has a plurality of patterns of the same size as the pattern of each chip formed on the wafer, which is called a mask pattern, and it is mass-production because it is a batch exposure. But 1:
Since the first transfer is performed, the alignment accuracy with the pattern on the wafer is synergistic with the pattern alignment accuracy. Then, the influence of the distortion of the master mask directly affects the accuracy. A third method is a method in which a mask having a pattern 5 times to 10 times larger than the pattern of a wafer or a master mask called a reticle mask is used, and this is subjected to reduction projection exposure onto a wafer substrate. This method is excellent in accuracy because it reduces the alignment (overlap) accuracy error between the pattern on the wafer and the pattern of the reticle mask because of reduced projection, and because it is a batch exposure, it is productive. Are said to be advantageous over the EB and FIB methods.

However, as described above, due to the demand for higher integration of IC and LSI elements, further miniaturization of the pattern on the wafer has come to be required.
Further accuracy is required for the overlay accuracy (positional accuracy) of the pattern on the wafer and the created pattern.

Under these circumstances, even in the reduction projection exposure method which is a third pattern forming method which is advantageous in terms of overlay accuracy with a pattern on a wafer, overlay accuracy at the current level (0.04 to 0.02 μm) is obtained. ) Better accuracy is required. In the case of DRAM, the overlay accuracy at the 16 Mbit level is required to be 0.02 to 0.01 μm or less. With this method, 1
Usually, 10 or more reticle masks are required to create one LSI, and the overlay accuracy between the patterns reduced and projected by each reticle mask is 0.0.
It is required to be 2 to 0.01 μm or less.

Further, in the field of color televisions and displays, the size has been increasing more and more in recent years, and the shadow masks and liquid crystal panels used therefor are also required to be large. Pattern masks for shadow masks and liquid crystal panels are required to be larger and finer (finer), and when an optical exposure machine is used, a desired pattern can be obtained by combining the patterns corresponding to the apertures. The number of aperture exposures increases, and along with that, the total exposure time increases, sometimes extending to day and night. Furthermore, when an electron beam exposure apparatus is used, a raster machine that draws a pattern by combining raster scanning and blanking takes an enormous amount of time because of area dependency, and a vector that vector scans a shaped beam is used. Even when a machine is used, since the scanning is performed corresponding to the aperture as in the case of the optical exposure machine, the time for the exposure drawing becomes long.

By the way, when the reticle pattern and the like are drawn by using an electron beam exposure apparatus and an optical exposure apparatus, the mask substrate is fixed in order to secure the positional accuracy of the drawn pattern and reduce the pattern distortion. It is already known that a reference mark is provided on a stage or a mask holder to be used, and the positional deviation at the time of drawing is corrected with reference to this mark.

[0008]

However, as described above, when the drawing time becomes longer with the miniaturization of the pattern, an apparatus such as an electron beam exposure apparatus or an optical exposure apparatus which is precisely managed and controlled. However, there is often a problem that the drawing accuracy is deteriorated due to temperature fluctuations, electric fluctuations, mechanical fluctuations, fluctuations of the position control system, etc. of the substrate to be drawn.
Particularly, in the case of a pattern plate having an alignment pattern such as a reticle mask, the position of the main pattern is controlled by the alignment pattern on the premise of an accurate positional relationship between the alignment pattern and the main pattern (device pattern). Therefore, it is necessary that the positional relationship between the alignment pattern and the main pattern is accurately drawn, but this positional relationship is also affected by the above items (1) to (3). Similarly, in the case of a shadow mask and a pattern plate for a liquid crystal panel, the above-mentioned effects 1 to 3 are also affected.

In most cases, the above-mentioned fluctuations (1) to (1) are due to one direction only, and is due to the difference between the temperature of the substrate itself and the ambient temperature of the stage used, and is electrically dependent. Is caused by a cassette or the like that fixes the substrate to be exposed, and the cassette is slightly displaced during the X and Y movements of the stage. It is considered that is due to atmospheric pressure and temperature fluctuations in the environment of the interferometer. In general, most of and are affected by the drawing size of the substrate and are almost proportional to the size of this pattern, and most of are
Although it is said that it is affected by the drawing time, in any case, there is a positional deviation (error) that is proportional to the drawing size and occurs according to the pattern size, and a positional deviation that occurs proportionally to the drawing time. Be divided. In particular, there is a problem due to the deviation due to, and when this deviation is large, the relative position between the alignment pattern and the main pattern becomes defective, and the main pattern is distorted. It should be noted that the positional deviation that occurs depending on the pattern size is relatively small.

The present invention has been made in view of such a situation, and an object thereof is to provide a pattern plate having an alignment pattern with an accurate positional relationship between the alignment pattern and the main pattern and to reduce distortion of the main pattern. It is to provide a drawing method capable of drawing.

[0011]

A method of drawing a pattern plate having an alignment pattern of the present invention which achieves the above object is a method of drawing a pattern plate having a main pattern such as a reticle pattern and a shadow mask pattern and an alignment pattern, The alignment pattern of the final product is formed on the substrate in advance, the photosensitive layer is applied to the substrate, then the position of the alignment pattern of the substrate is read,
This method is characterized by drawing the main pattern while controlling the relative position of the drawing beam with respect to the position.

In this case, the position of the alignment pattern can be read by an optical beam different from the main pattern drawing light beam using an optical exposure apparatus. For example, an i-line resist is used as the photosensitive layer. It is possible to use i-line light as the main pattern writing light beam and YAG laser light as the alignment pattern position reading light beam.

It is also possible to use an electron beam exposure apparatus to read the position of the alignment pattern and draw the main pattern with the same electron beam so that the intensity of the electron beam is weakened when the position of the alignment pattern is read. ..

The present invention includes a pattern plate having an alignment pattern drawn by the above drawing method.

[0015]

According to the present invention, the alignment pattern of the final product is formed on the substrate in advance, the photosensitive layer is applied to the substrate, the position of the alignment pattern of the substrate is read, and the drawing beam is moved relative to the position. Since this pattern is drawn while controlling the position, it is possible to completely suppress the decrease in drawing accuracy due to mechanical fluctuations such as misalignment during drawing of the cassette that fixes the substrate, and to change the relative position of this pattern to the alignment pattern. It is possible to draw with high accuracy, and it is possible to draw with little distortion of this pattern. Since the alignment pattern itself used as the position reference for drawing the main pattern is also used for alignment with the pattern on the wafer, the transfer accuracy of the main pattern is extremely high.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below, with reference to the drawings, of an example in which the drawing method of a pattern plate having an alignment pattern of the present invention is applied to a reticle mask. As shown in the plan view of FIG. 1, a main pattern B forming a device pattern on a substrate 1 and an alignment pattern A1 around the main pattern B passing through the X-direction center and the Y-direction center of the main pattern B, for example.
When manufacturing a reticle mask in which A2 and A3 are arranged, first, as shown in FIG. 2, alignment patterns A1, A2, and A3 are accurately drawn on the substrate 1 by an arbitrary method. Since these alignment patterns A1, A2, A3 are used as alignment patterns for the reticle mask which is the final product, they are accurately drawn at predetermined relative positions.

Next, a resist 2 is applied to the entire surface of the substrate 1 as shown in FIG. 3, and thereafter, the resist 2 is set in an electron beam exposure apparatus or an optical exposure apparatus and a main pattern B is drawn. At that time, the alignment patterns A1 and A2 are formed by the drawing beam of the exposure apparatus or the reading beam different from the drawing beam.
2 and A3 are read, scanning is performed while accurately controlling the relative position of the drawing beam with respect to these positions, and latent images of the main pattern B are sequentially drawn as shown in FIG. In this way, the alignment patterns A1, A2,
By advancing the drawing of the main pattern while referring to A3, it is possible to completely suppress the decrease in the drawing accuracy due to the mechanical variation due to the cassette or the like for fixing the substrate 1, and to compare the main pattern B with the alignment pattern. The position can be drawn with high accuracy, and the distortion of the main pattern B can be drawn with little distortion. Then, the alignment patterns A1, A2, which are used as reference positions for drawing this pattern,
Since A3 itself is also used for alignment with the pattern on the wafer, considering that normally 10 or more reticle masks are sequentially aligned to create an LSI or the like, such a drawing method is extremely effective. I understand. After forming the latent image of the main pattern B, by developing the resist 2,
The reticle mask as shown in FIG. 1 is completed.

By the way, when the alignment patterns A1, A2, A3 on the substrate 1 are read by the exposure device, the resist 2 coated thereon is exposed by the reading beam, and the alignment patterns A1, A2,
A3 will be destroyed. To avoid this, when writing is performed using an optical exposure apparatus, the positions of the alignment patterns A1, A2, and A3 may be read by using light having a wavelength that the resist 2 does not sensitize, separately from the writing light beam. Good. For example, as resist 2, i
The line resist is used to scan and draw the i-line light from the Ar laser, and the YAG laser light is scanned to read the positions of the alignment patterns A1, A2, and A3. When the electron beam exposure apparatus is used, the alignment patterns A1, A2, and A3 are read by the drawing electron beam, but the beam current irradiation amount at the time of reading is kept lower than the beam current irradiation amount at the time of writing the main pattern B. By controlling the residual film of the resist 2, the above problem can be avoided.

The alignment patterns A1, A2, A3 may be read at all times during the drawing of the main pattern B during the drawing period, and the position of the drawing beam may be controlled based on the data.
It is also possible to read only at a specific time of the drawing period, for example, at the sampling time during that time, and correct the positional deviation of the drawing beam based on the data.

Although the reticle mask for semiconductor exposure having the alignment pattern on the periphery has been described above, the drawing method of the present invention is applied to the shadow mask pattern plate having the alignment pattern for alignment and for the liquid crystal panel. It can also be applied to drawing an electrode pattern plate of

[0021]

As described above, according to the method of drawing a pattern plate having an alignment pattern of the present invention and the pattern plate drawn by the method, the alignment pattern of the final product is formed on the substrate in advance, and the substrate The photosensitive layer is applied to the substrate, then the position of the alignment pattern on the substrate is read, and the main pattern is drawn while controlling the relative position of the drawing beam with respect to that position. It is possible to completely suppress a decrease in drawing accuracy due to mechanical fluctuations such as the above, it is possible to draw the relative position of the main pattern with respect to the alignment pattern with high accuracy, and it is possible to draw with little distortion of the main pattern. Since the alignment pattern itself used as the position reference for drawing the main pattern is also used for alignment with the pattern on the wafer, the transfer accuracy of the main pattern is extremely high.

[Brief description of drawings]

FIG. 1 is a plan view of a reticle mask drawn by a drawing method of the present invention.

FIG. 2 is a plan view of a substrate on which an alignment pattern is formed.

FIG. 3 is a plan view of a substrate coated with a resist.

FIG. 4 is a plan view during drawing of the main pattern.

[Explanation of symbols]

 A1, A2, A3 ... Alignment pattern B ... Main pattern 1 ... Substrate 2 ... Resist

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01L 21/027

Claims (5)

[Claims] 1. In a method of drawing a pattern plate having a main pattern such as a reticle pattern, a shadow mask pattern, and an alignment pattern, an alignment pattern of a final product is previously formed on a substrate, a photosensitive layer is applied to the substrate, and then A method of drawing a pattern plate having an alignment pattern, characterized in that the position of an alignment pattern on a substrate is read and the main pattern is drawn while controlling the relative position of a drawing beam with respect to the position. 2. The pattern having an alignment pattern according to claim 1, wherein the position of the alignment pattern is read by a light beam different from the light beam for pattern drawing using an optical exposure apparatus. How to draw a plate. 3. An i-ray resist is used as the photosensitive layer,
3. The method of drawing a pattern plate having an alignment pattern according to claim 2, wherein i-ray light is used as the light beam for drawing the pattern, and YAG laser light is used as the light beam for reading the alignment pattern position. 4. An electron beam exposure apparatus is used to read the position of the alignment pattern and draw the main pattern with the same electron beam, and weaken the intensity of the electron beam when reading the position of the alignment pattern. A method of drawing a pattern plate having an alignment pattern according to claim 1. 5. A pattern plate having an alignment pattern drawn by the drawing method according to claim 1. Description: