JP3140516B2 - Drawing method of pattern plate having alignment pattern and pattern plate drawn by the method - Google Patents

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 producing a pattern by projecting the pattern onto a wafer or a master mask substrate. The present invention relates to a method for drawing a large-size pattern plate used for a mask or the like.

[0002]

2. Description of the Related Art In recent years, ICs and LSIs have been increasingly integrated, and DRAMs of 4 Mbits have already entered the mass production stage and are shifting to 16 Mbits and 64 Mbits. Along with this, the dimensions of the circuit elements on the wafer are required to be further miniaturized, and patterning by lithographic techniques for creating circuit elements on the wafer is also required to respond to miniaturization. .

As a method of forming a pattern on a wafer, there are usually the following three methods. The first method is a method using an EB (electron beam) device or a FIB (focused ion beam) device, in which a pattern is formed directly on a wafer by controlling an electron beam or an ion beam. In this case, since the writing position is controlled in accordance with the pattern on the wafer, the patterning accuracy depends only on the position detection ability and the writing position control ability. Some problems still remain in the position detection capability and the position control capability. This method
This is a method that is not suitable for mass production because a pattern is created one by one and drawing time is required. The second method is
A method called a mask pattern, in which a mask having a plurality of patterns of the same size as the pattern of each chip formed on the wafer is imposed and transferred to the wafer substrate. But 1:
Since the transfer of 1 is performed, the alignment accuracy with the pattern on the wafer is directly multiplied by the pattern alignment accuracy. And the influence of the distortion of the master mask directly affects the accuracy. A third method is to use a mask called a reticle mask having a pattern having a size of 5 to 10 times the size of a pattern of a wafer or a master mask, and subject the wafer to reduced projection exposure on a wafer substrate. This method is excellent in accuracy because of the reduction projection, which also reduces the alignment (overlay) accuracy error between the pattern on the wafer and the pattern of the reticle mask. Is considered to be more advantageous than the EB or FIB method.

However, as described above, the demand for higher integration of ICs and LSI elements has required a further finer pattern on a wafer.
There is also a demand for a further improvement in the overlay accuracy (alignment accuracy) between the pattern on the wafer and the pattern to be created.

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

[0006] In the field of color televisions and displays, the size has been increasing in recent years, and the shadow masks and liquid crystal panels used for them have also been required to be increased in size. The size of a pattern plate for a shadow mask and a liquid crystal panel is required to be finer (finer) as well as larger. When a light exposure machine is used, a desired pattern can be obtained by a combination of pictures corresponding to the aperture. The number of aperture exposures increases, and accordingly, the overall 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 the area dependence. In the case of using an apparatus, the scanning is performed corresponding to the aperture as in the case of the optical exposure apparatus, so that the time for the exposure and drawing becomes long.

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

[0008]

However, as described above, when the drawing time is prolonged with the miniaturization of the pattern, an apparatus which is precisely managed and controlled, such as an electron beam exposure apparatus or a light exposure apparatus. However, a problem often arises in that the accuracy of writing is lowered due to temperature fluctuations, electrical fluctuations, mechanical fluctuations, fluctuations in the position control system, etc. of the substrate on which the image is to be drawn.
In particular, 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). For this purpose, 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. Similarly, in the case of a shadow mask and a pattern plate for a liquid crystal panel, the above-mentioned effects are also applied.

Most of the above-mentioned fluctuations are caused in one direction, and the fluctuations are considered to be caused by the difference between the temperature of the substrate itself and the environmental temperature of the stage used. Is caused by a cassette or the like for fixing a substrate to be exposed, and is caused by a slight displacement of the cassette during the X and Y movements of the stage. Also, it is considered that the variation is caused by the atmospheric pressure and temperature fluctuation of the environment of the interferometer. In general, most of and a part of are almost proportional to the dimensions of the pattern affected by the drawing size of the substrate, and most of are
In any case, the position shift (error) that is proportional to the drawing size and occurs in accordance with the pattern size, and the position shift that occurs in proportion to the drawing time are considered to be affected by the drawing time. Divided. In particular, there is a problem with the deviation caused by the above. If the deviation is large, the relative position between the alignment pattern and the main pattern becomes defective, and the main pattern is distorted. Note that the positional deviation that occurs according to the pattern size is relatively small.

The present invention has been made in view of such circumstances, and has as its object to provide a pattern plate having an alignment pattern in which the positional relationship between the alignment pattern and the present pattern is accurate and the distortion of the present pattern is small. An object of the present invention is to provide a drawing method capable of drawing.

[0011]

According to the present invention, there is provided a method for drawing a pattern plate having an alignment pattern and a pattern plate having an alignment pattern, such as a reticle pattern and a shadow mask pattern. Form the alignment pattern of the final product on the substrate in advance, apply the photosensitive layer to the substrate, then read the position of the alignment pattern on the substrate,
This method is characterized in that the present pattern is drawn 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 another light beam different from the pattern drawing light beam using an optical exposure apparatus. For example, an i-line resist is used as the photosensitive layer. In this case, i-line light can be used as the main pattern drawing light beam, and YAG laser light can be used as the alignment pattern position reading light beam.

Further, the position of the alignment pattern and the writing of the main pattern may be performed using the same electron beam by using an electron beam exposure apparatus, and the intensity of the electron beam may be reduced when reading the position of the alignment pattern. .

[0014]

[0015]

According to the present invention, an alignment pattern of a final product is formed on a substrate in advance, a photosensitive layer is applied to the substrate, then the position of the alignment pattern on the substrate is read, and the position of the writing beam relative to the position is read. Since the present pattern is drawn while controlling the position, it is possible to completely suppress a decrease in the drawing accuracy due to mechanical fluctuations such as a displacement during drawing of a cassette or the like for fixing the substrate, and to determine a relative position of the present pattern with respect to the alignment pattern. The pattern can be drawn with high accuracy, and the pattern can be drawn with little distortion. Since the alignment pattern itself used as a position reference for writing the main pattern is also used for alignment with, for example, a pattern on a wafer, the accuracy of transferring the main pattern is extremely high.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a method for drawing a pattern plate having an alignment pattern according to the present invention. As shown in a plan view in 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 center of the main pattern B in the X and Y directions, for example.
When manufacturing a reticle mask on which A2 and A3 are arranged, first, as shown in FIG. 2, the alignment patterns A1, A2 and A3 are accurately drawn on the substrate 1 by an arbitrary method. Since the alignment patterns A1, A2, and A3 are used as alignment patterns of a reticle mask as a 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 then set in an electron beam exposure apparatus or an optical exposure apparatus to draw the pattern B. At this time, the alignment patterns A1 and A1 are drawn by the drawing beam of the exposure apparatus or a reading beam different from the drawing beam.
2. A3 is read, and scanning is performed while accurately controlling the relative position of the writing beam with respect to those positions, and a latent image of the main pattern B is sequentially drawn as shown in FIG. As described above, the alignment patterns A1, A2,
By advancing the writing of the present pattern while referring to A3, it is possible to completely suppress a decrease in the writing accuracy due to the mechanical fluctuation caused by the cassette or the like for fixing the substrate 1, and to reduce the relative position of the present pattern B to the alignment pattern. The position can be drawn with high accuracy, and the pattern B can be drawn with little distortion. Then, the alignment patterns A1, A2,
Since A3 itself is also used for alignment with a pattern on a wafer, such a drawing method is extremely effective in considering that usually 10 or more reticle masks are sequentially aligned to create an LSI or the like. I understand. After forming the latent image of the pattern B, the resist 2 is developed,
A reticle mask as shown in FIG. 1 is completed.

When reading the alignment patterns A1, A2, and A3 on the substrate 1 by the exposure apparatus, the resist 2 applied thereon is exposed by the read beam, and the alignment patterns A1, A2,
A3 will be destroyed. To avoid this, when drawing using an optical exposure apparatus, the positions of the alignment patterns A1, A2, and A3 are read by light having a wavelength at which the resist 2 is not exposed, separately from the drawing light beam. Good. For example, if the resist 2 is i
Using a line resist, drawing is performed by scanning i-line light from an Ar laser, and the positions of the alignment patterns A1, A2, and A3 are read by scanning a YAG laser beam. When an electron beam exposure apparatus is used, the alignment patterns A1, A2, and A3 are read by the writing electron beam, and the beam current irradiation amount at the time of reading is suppressed to be lower than the beam current irradiation amount at the time of writing the pattern B. By controlling the residual film of the resist 2, the above problem can be avoided.

When the alignment patterns A1, A2, and A3 are read at the time of writing the pattern B, the alignment patterns A1, A2, and A3 may be read at all times during the writing period, and the position of the writing beam may be controlled based on the data.
The reading may be performed only at a specific timing of the writing period, for example, at a sampling time during the writing, and the positional deviation of the writing beam may be corrected based on the data.

In the above description, a reticle mask for semiconductor exposure having an alignment pattern around it has been described. However, the drawing method of the present invention relates to a shadow mask pattern plate having an alignment pattern for alignment, a liquid crystal panel. It can also be applied to drawing of an electrode pattern plate or the like.

[0021]

As described above, according to the method for writing a pattern plate having an alignment pattern 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 on the substrate is read, and this pattern is formed while controlling the relative position of the drawing beam with respect to the position. Since the drawing is performed, it is possible to completely suppress a decrease in the drawing accuracy due to a mechanical fluctuation such as a displacement during drawing of a cassette or the like for fixing the substrate, and to accurately draw a relative position of the present pattern with respect to the alignment pattern. Drawing can be performed with little pattern distortion. Since the alignment pattern itself used as a position reference for writing the main pattern is also used for alignment with, for example, a pattern on a wafer, the accuracy of transferring the main pattern is extremely high.

[Brief description of the 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 on which a resist is applied.

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

[Explanation of symbols]

 A1, A2, A3: Alignment pattern B: This pattern 1: Substrate 2: Resist

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 1/08 G03F 1/00 G03F 9/00 H01L 21/027

Claims (4)

(57) [Claims] In a method of drawing a pattern plate having an alignment pattern and a main pattern such as a reticle pattern and a shadow mask pattern, an alignment pattern of a final product is previously formed on a substrate, a photosensitive layer is applied to the substrate, A method of drawing a pattern plate having an alignment pattern, comprising reading a position of an alignment pattern on a substrate, and writing a main pattern while controlling a relative position of a writing beam with respect to the position. 2. A pattern having an alignment pattern according to claim 1, wherein the position of said alignment pattern is read by another light beam different from the pattern drawing light beam using an optical exposure apparatus. How to draw the plate. 3. An i-line resist is used as the photosensitive layer,
3. The method according to claim 2, wherein i-line light is used as the pattern drawing light beam and YAG laser light is used as the alignment pattern position reading light beam. 4. An electron beam exposure apparatus, wherein the position reading of the alignment pattern and the writing of the main pattern are performed by the same electron beam, so that the intensity of the electron beam is reduced when reading the position of the alignment pattern. A method for drawing a pattern plate having an alignment pattern according to claim 1.