KR100476819B1 - A photolithography apparatus and mask for nano meter scale patterning of some arbitrary shapes - Google Patents

Abstract

The present invention relates to an exposure apparatus for patterning an arbitrary shape to nanometer-class, and since only the mask needs to be changed when fabricating a new circuit, it is possible to innovatively lower the unit cost of the chip during the semiconductor process and also require nanometer processing. The present invention relates to an exposure apparatus for patterning an arbitrary shape to a nanometer level that can facilitate research and production in the field, and a method of manufacturing a mask in which a freer transformed pattern is formed.

In particular, it is possible to pattern arbitrary shapes to nanometer level without any special additions to the exposure apparatus by making masks with freer transformed patterns by freer transforming by removing the negative numbers after making arbitrary shapes in the form of origin symmetry. .

An exposure apparatus for patterning an arbitrary shape of the present invention to a nanometer class, the exposure apparatus for patterning an arbitrary shape of the present invention to a nanometer class for achieving the above object is a light source unit having a lamp for providing a light source, the A mask unit for mounting a mask on which light of a light source passes and formed with a pre-converted pattern, a lens unit including at least one lens for freer converting light past the mask unit, and a PR on which a photoresistor is deposited Provided is an exposure apparatus using a mask formed with a free-conversion pattern characterized in that it comprises a portion.

In addition, the present invention comprises the steps of manufacturing an arbitrary shape using a unit pixel of a constant size, the step of producing a file for the arbitrary shape by digitizing the fabricated arbitrary shape portion and other portions, the arbitrary Fabricating an arbitrary shape file of symmetry including an origin symmetry of the shape file of the file or any shape file corresponding to the origin, top, bottom, and left and right symmetry; It provides a method of producing a pre-transformed pattern, characterized in that it comprises the step of removing the negative portion of the pre-transformed file.

Description

A photolithography apparatus and mask for nano meter scale patterning of some arbitrary shapes

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for patterning arbitrary shapes to nanometer-class and a method of fabricating a mask having a freer transformed pattern. Particularly, the negative shape is removed after freer transforming by forming an arbitrary shape in the form of origin symmetry. In this method, a mask having a pattern formed by freer conversion (hereinafter referred to as "FT") is fabricated, and by using this, an arbitrary shape can be patterned to nanometer level without any special addition to the exposure apparatus, so that the equipment is inexpensive and operated. It is easy to change the pattern of the freer when manufacturing a new circuit, so that not only can the chip cost be lowered in the semiconductor process, but also the research and production in all fields requiring nanometer processing can be facilitated. A method of manufacturing an exposure apparatus and a mask for patterning an arbitrary shape at a nanometer scale.

Modern society is a time of rapid change, with new technologies emerging every day. As new technologies emerge, they create new demands, which in turn require newer technologies. For example, the density of DRAM has increased by 50% every year, and the microprocessor has increased by 35% every year. As a result, the yield for making chips continues to increase, and the cost corresponding to one chip continues to be lowered. The exposure technology necessary to manufacture such LSI and system-on-a-chip has been developed continuously, and the most actively developed is the exposure technology.

A good exposure device is one whose size is reduced while the image remains intact without diffraction, and is engraved on the PR (photoresist) at the minimum line width. The diffraction phenomenon means that the light travels in a direction different from the incident direction by changing the path according to the distance away when the light passes near the interface of the mask, and the minimum line width is the minimum width of the line that can be drawn on the silicon chip. However, as the wavelength becomes shorter, the diffraction phenomenon cannot be avoided, and the minimum line width is also limited. A conventional exposure apparatus will be described with reference to FIG.

1 is an optical system diagram of a conventional exposure apparatus.

As shown in FIG. 1, a conventional exposure apparatus is a light source required for patterning as one of an optical light source such as a G-line, an H-line, an F ₂ laser, and extreme ultraviolet light or a non-optical light source such as an electron beam, an ion beam, and an X-ray. (11), a silicon wafer 16 coated with PR as the light source 11, a general mask 13 and a light source 11 having a shape to be engraved on the silicon wafer 16 with the light source 11 as a mask 13 Condenser 12 for collecting the light into the silicon wafer 16, and projection lenses 14 and 15 for converging the shape of the mask 13 made of the light collected by the condenser 12, and the optical system. It is an additional device for canceling out the diffraction phenomenon, and it is composed of one means filter (not shown) to improve the minimum line width.

In the above-described configuration, the filter may or may not be used and its position is located between the projection lenses 14 and 15.

Such conventional exposure apparatus may be classified into an exposure apparatus using a non-optical system and an exposure apparatus using an optical system. The non-optical exposure apparatus includes an electron beam exposure apparatus, an ion beam exposure apparatus, an X-ray exposure apparatus, an accelerator such as a synchrotron. Used exposure apparatuses;

The electron beam exposure technique is a method of exposing a resistor using kinetic energy of electrons irradiated on a wafer by focusing, accelerating and deflecting electrons emitted from a cathode by an electromagnetic field. The wavelength of the electron beam may be about several angstroms to implement a high resolution, but this has a disadvantage in that productivity is significantly reduced since direct writing is performed by controlling the path of the electron beam.

Next, an exposure apparatus using an ion beam exhibits excellent characteristics as an ultrafine pattern forming exposure technique compared to electron beam exposure and X-ray exposure, but has the same disadvantages as the electron beam exposure. In addition, since the ion is relatively heavy, the substrate is damaged. There are disadvantages to wear.

Next, the X-ray light source is a wavelength of 4-50 알려진 known as soft X-ray and has excellent permeability to carbon, which is the main component of dust, so that defects caused by dust or organic contaminants present on the mask are generated. Although there is an advantage that can be minimized, the sensitivity of the organic-based resistor is low, the exposure time is long compared to the light intensity, the productivity is low.

Finally, the Cyntrontron Radiation Accelerator is a device that exposes electrons in circular motion to electromagnetic waves emitted in the tangential direction of circular motion (wavelength is about 1 nm) .It has directionality and high brightness in the tangential direction of circular motion. It is suitable but has the disadvantage that the radiation accelerator is too expensive.

As described above, the non-optical exposure apparatus is not suitable for mass production because of the disadvantage that the equipment is expensive and the production yield is low despite the advantage that the minimum line width is very small.

Next, an exposure apparatus using an optical system will be described.

2 is a graph for each year of the minimum line width improvement trend with respect to the wavelength of use of the optical system light source.

The light source shown in FIG. 2 is a light source of an optical exposure apparatus, and shows the discontinuous spectrum of mercury and the wavelength of the laser in chronological order. As shown in FIG. 2, in order to improve the minimum line width, a trend is being developed from a normal light source to a laser and from a long wavelength to a short wavelength. The reason for using a laser is because of the advantage of bright light than a normal light source. However, in the case of materials exposed to weak light, a common light source having a much wider wavelength selection may be used. In order to achieve a minimum line width of less than 100 nm, a light source with a wavelength of less than 200 nm should be used. As a result of the current trend, there is no further progress at the 60 nm minimum line width. The minimum line width of the prior art is 100 nm or less and the minimum line width R is the wavelength and

(One)

Is in a relationship. Therefore, it can be seen that the shorter the light source in the exposure apparatus has the minimum line width, and the laser is currently being studied. Furthermore, Extreme Ultra-Violet (EUV) with a wavelength of 11-13 nm is a slightly longer area than soft X-rays and has been spotlighted as an exposure technology that can be used for a minimum line width of 70 nm or less. In the case of such extreme ultraviolet rays, a reflection type optical exposure apparatus should be used, and since the mirror is too inadequate in reflectance, it is preferable to increase the reflectance by using a mirror having a relatively large refractive index and deposited in a multiple film form. When the optical exposure apparatus is configured, the number of mirrors should be reduced to 6 or less if possible, and an aspherical mirror should be used, but the surface roughness of the surface should be about 0.1 to 0.2 nm.

However, the exposure apparatus using the extreme ultraviolet rays can reduce the minimum line width, and can make the size of the entire product of the exposure apparatus small, but the price is expensive, so it is not widely used.

The minimum line width R (resolution) and depth of focus (DOF) of a general optical system exposure apparatus may be expressed as follows.

(2)

The depth of focus corresponds to the length of the focal length in the longitudinal direction. In order to expose a single exposure, the PR thickness must be thinner than the depth of focus. In equation 2 Is the wavelength of the light source and NA is the numerical aperture of the projection lens system. remind And NA are useful parameters that can be defined when light converges or diffuses at a constant rate, such as lenses or optical fibers.

3 is a view for explaining a numerical aperture calculation formula of the lens.

In FIG. 3, when the diameter of the lens is D, the focal length is f, and the refractive index of the material around the lens is n, the numerical aperture is defined as follows.

(3)

Where α corresponds to half the angle at which light spreads. Meanwhile the number of lenses to be.

In Equation 2, k ₁ and k ₂ are values that need to be determined experimentally because they depend on the material of the PR, the exposure treatment technique, and the image forming technique to improve the minimum line width. Commonly used imaging techniques include phase shift masking, off-axis illumination, optical proximity correction, degree of coherence, intensity distribution in the aperture plane, lens aberration, and geometrical shapes (or spatial frequencies).

k ₁ is theoretically at least 0.25 and is known to be about 0.8 in the best system. Ideal case for using noncoherence sources Become, If and , If Becomes

The most ideal condition in the exposure apparatus is that the minimum line width R is small and the depth of focus DOF is increased. This is because the greater the depth of focus, the flatness of the plane of the PR does not have to be good, and the distance from the projection lens to the PR does not have to be strictly observed.

In Equation 2, the minimum line width can be reduced by reducing the wavelength of the light source, increasing the numerical aperture of the projection lens system, or reducing the k ₁ by introducing a technique such as a filter. Reducing the numerical aperture decreases the minimum line width, but reduces the depth of focus even more, requiring a finer process of applying the exposure material, and thus increasing the accuracy between the lens and the exposure material. Reducing the wavelength means that ultraviolet, extreme and X-ray light sources are used for exposure to visible light. By principle, the minimum line width is noticeably reduced, but the cost of exposure equipment increases exponentially. Especially in the case of F2 laser, all the exposure equipment should be basically put in the vacuum chamber because the wavelength is absorbed by oxygen or moisture in the air. Creating and maintaining this enormous volume of vacuum would be costly, making it unsuitable for practical use. The depth of focal length is expressed as the minimum line width of Equation 2 as follows.

(4)

Looking at Equation 4 and thinking about how to increase the depth of focus, it would be possible to reduce the wavelength or reduce k ₁ using a phase shift filter, but there are limits to how to reduce k ₁ .

Many of the articles published on the conventional exposure apparatus relate to a technique of reducing k ₁ , which can be divided into a technique of adjusting a light source among the optical components of FIG. 1 and a technique of using a filter in the projection lens system.

If the depth of focus is thicker than the minimum required exposure thickness, no problem occurs, but if the depth of focus is shorter than this, problems may occur. The exposure thickness must be able to withstand the etching process, and in order to function as an original PR, the exposure thickness must be at least a predetermined minimum thickness.

In the prior art, an illumination optical system in which a grating having a period of 1/2 is manufactured by a dual spatial frequency system, which interferes with +1 and -1 diffracted beams, increases its resolution and doubles the resolution. Registration number 10-0049064-0000), using a phase shift mask to improve the MTF characteristics and image contrast of the exposure apparatus (Korean Patent Registration No. 10-0114334-0000) and the shape of the mask to be etched on the mask. There is a method using a filter other than a mask, and in order to reduce the minimum line width, an exposure apparatus using EUV, electron beam, ion beam, X-ray exposure apparatus, and radiation accelerator should be used as next-generation exposure apparatus. It is not suitable for mass production because of the disadvantage of high cost and low production yield because it requires equipment. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to pattern nanometers with a single mask without adding a filter, and is simple and easy to operate. Its purpose is to provide an exposure apparatus.

 An exposure apparatus for patterning an arbitrary shape of the present invention to a nanometer level for achieving the above object is equipped with a light source unit having a lamp for providing a light source, a mask formed with a pattern through which the light of the light source passes and free-converted A mask unit including a mask unit including at least one lens for pre-converting light passing through the mask unit, and a PR unit on which a wafer on which a photoresistor is deposited is mounted; An exposure apparatus to be used is provided.

In addition, the present invention comprises the steps of manufacturing an arbitrary shape using a unit pixel of a constant size, the step of producing a file for the arbitrary shape by digitizing the fabricated arbitrary shape portion and other portions, the arbitrary Fabricating an arbitrary shape file of symmetry including an origin symmetry of the shape file of the file or any shape file corresponding to the origin, top, bottom, and left and right symmetry; It provides a method of producing a pre-transformed pattern, characterized in that it comprises the step of removing the negative portion of the pre-transformed file.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the exposure apparatus for patterning an arbitrary shape according to a preferred embodiment of the present invention in nanometer class.

The present invention relates to freer optics, and in terms of its structure, it belongs to an exposure apparatus. Fourier optics means an integral process of forming a mask image using freer transform and its inverse transform. Freer optics using multiple lenses require four basic operators: quadratic phase calculation, scaling operation, freer transform operation, and free-space transfer operation, depending on their distance, such as distance between lenses. The method of describing freer optics is called the Nazarad and Shamir methods.

Two-dimensional function Freer Transformation of Is given by

(5)

In this expression Means freer transformation Wow Is called a spatial frequency, and the spatial coordinates x and y are corresponding Fourier pairs. Equation 5 is a two-dimensional function When you know that freer transformation It is used in the case of, and vice versa, an inverse Fourier transform should be used.

(6)

In Equation 6 Means an inverse freer transform. Combining Equations 5 and 6 yields seven theorems useful in freer transforms. Wow The two operations are applied successively.

(7)

The meaning of Equation 7 is to take a freer transform and an inverse freer transform in succession to obtain a function that is symmetric about the origin of the original function. In optics, it is convex that acts as a freer transducer like Equation 7.

4 is a view for explaining the principle of a convex lens used as a freer converter.

In FIG. 4, the optical axis direction of the lens is z, and the plane on which the lens is placed is xy-plane, and the thickness of the convex lens is shown. And the refractive index of the medium constituting the convex lens is n, and considering the phase change according to the lens thickness, the light incident from the center of the lens to (x, y) obtains the following phase change.

(8)

In the above equation, k means wave number And f is the focus of the convex lens. The phase change given by Eq. 8 is the phase difference between the back plane and the front plane of the light entering and exiting the lens. Combining Equation 8 and the four basic operators gives the final result at the focal position of the convex lens.

(9)

In Equation 9, the integral expression is compared with Equation 5, and it can be seen that if the variable is properly substituted, it is freer transformed. Equation 9 shows that when parallel light enters the lens, the back plane of the lens is exactly freer transformed from the focal plane.

Now let's look at an example of freer conversion through convex lenses.

5 is a three-dimensional graph simulating the intensity distribution of the freer transformed light at the focus position,

FIG. 6 is a three-dimensional graph simulating the distribution of intensity of freer transformed light at a distance that is half the focal length and the lens.

The result of freer conversion of a rectangular aperture of 500 nm x 800 nm through the lens shows that the distribution of light intensity varies with the position away from the lens when the shape of the mask is close to the wavelength. have.

Now, an embodiment of the present invention will be described in detail with reference to FIG. 7.

7 is a schematic optical system diagram of an exposure apparatus of the present invention.

The exposure apparatus according to the present invention includes a light source unit 20 having a lamp that provides an optical light source, a vacuum pump 34 for minimizing plasma phenomenon of air, a vacuum pump port 39 connected to the vacuum pump 34, and It consists of several lenses 36 and the spatial filter 37, and finely adjusts the focus of the lens 36 and the position of the spatial filter 37 to produce a light source having a cross-sectional area of a predetermined size ( 30), the mask unit 40 including the freer transformed mask of the image to be made while controlling the amplitude or phase of the light beam passing through the light source enlargement unit 30, and the freer conversion of the light beam passing through the mask unit 40. The lens unit 50 includes a lens unit 50 having a lens, a PR unit 60 having a photoresistor (PR) on which the photoresistor is deposited, and a blocking device for blocking light irrelevant to exposure to the wafer. In addition, the light source unit 20, the light source expansion unit 30, the mask unit 40, the lens unit 50 and the PR unit 60 is provided with an adjustment device for finely adjusting up, down, left and right, and the light source unit 20 ), Each support 22, 32, 42, 52, 62 and all the supports 22 for supporting the light source enlarged portion 30, the mask portion 40, the red portion 50, and the PR portion 60. , 32, 42, 52, 62 is made to include an optical bench 70 to prevent the position and height of the support is easily changed to external shock and internal vibration. Furthermore, the optical bench 70 can stably mount the optical bench 70 and is mounted on the optical table 72 to prevent vibration from the outside. However, the optical table 72 becomes unnecessary when a high pulse laser connected to the light source expanding unit 30 through the optical fiber is used as the light source.

Hereinafter, each part of the exposure apparatus will be described in detail.

First, the light source unit 20 may have a different structure depending on what the light source is. If a monochromatic light source is used, a color filter for extracting monochromatic light from the lamp and a lens and aperture for parallelizing the light source are required, whereas a laser light source may be used only.

Next, the light source expansion unit 30 receives light emitted from the light source unit 20 in the form of substantially parallel light, and the light rays passing through the light source expansion unit 30 do not necessarily have to be parallel light. Thus, depending on the situation, it may be a light that spreads out or a light that converges. In addition, the light source enlargement unit 30 uses the vacuum pump 34 to minimize the plasma phenomenon of air, and the plasma is parallel light of the laser enters the light source enlargement unit and passes through the lens system to focus at least once in the path. In this case, the laser beam plasmas the gas in the air so that white flashes appear near the focal point. The white flashes thus formed form an image that is excessively distorted in the final nanometer image formation, and the vibration by the vacuum pump to remove the plasma phenomenon will not be a problem because the exposure time is very short using the pulse laser. Removing the high frequency of the vacuum pump for perfect exposure will result in more efficient exposure. It is preferable to use the light source enlargement support stand 32 as a method of removing a vibration. Furthermore, if the entire exposure apparatus is placed in a vacuum chamber and the light is sufficiently blocked, the exposure apparatus can be used in any environment.

Next, the mask unit 40 may mount a mask on which a freer transformed pattern having a shape of a shape to be finally formed is formed, and the mask unit 40 may be included in the lens unit 50.

Next, the lens unit 50 may be composed of one lens or several lenses therein, and the lens 54 may be appropriately used as the convex lens, the concave lens, the convex mirror, and the concave mirror. The number of lenses 54 is selected according to the desired resolution, which will be described in detail later in the operating principle of the exposure apparatus according to the present invention.

In order to pattern using the exposure apparatus according to the present invention, since a mask on which a freer converted pattern is first mounted on the mask part is required, a method of manufacturing a mask on which a freer converted pattern is formed will be described.

The freer-converted pattern is made through six steps, and the first step is to draw a shape of an image to be made using the exposure apparatus of the present invention.

8 is a shape to be finally made by the exposure apparatus of the present invention.

The figure of FIG. 8 exists in the form of a picture file stored in a computer after drawing using a drawing tool, that is, paper and pencil or a computer, and the shape may be symmetrical as shown in FIG. It may be an arbitrary shape that is not symmetric in any direction. The small pieces of the checkerboard of FIG. 8 represent pixels, and the number of pixels of the minimum feature size is determined by the number of different line widths in the picture.

The second step is to digitize the picture.

FIG. 9 is a diagram illustrating conversion data obtained by digitizing FIG. 8 to 0 and 1. FIG.

8 may be represented by 0 and 1 as shown in FIG. 9. In FIG. 8, a white pixel may be referred to as 1, a dark pixel may be referred to as 0, and a dark pixel may be referred to as 1 according to a material type such as PR or intaglio or how the picture is drawn. have. As shown in FIG. 9, the numerical value of FIG. 8 can be easily made into a file using a general conversion program.

The third step is to make the quantized data origin-symmetric. The method of origin symmetry will be described with reference to FIGS. 10 and 11.

10A and 10B are diagrams illustrating two opposing objects for explaining a method of performing origin symmetry on digitized data.

11A and 11B are diagrams illustrating four facing objects for explaining a method of performing origin symmetry on digitized data.

As in FIG. 10A, when a freer transform of an arbitrary shape that is not in the form of origin symmetry cannot be formed in a mask, an arbitrary shape must be made in the form of origin symmetry before freer conversion.

Assuming that the mask to be etched on the wafer is in the form of Fig. 10a,

10

Become. If you put the mask symmetrically at the origin as in Figure 10b, the mask in the first quadrant Represented by, the mask in the third quadrant It is expressed as Thus, substituting this into Eq. 10 yields:

(11)

If the mask is placed in a symmetrical form as shown in Fig. 10b, it becomes as in Equation 11. 11A and 11B can also create origin symmetry using the same approach.

The result of freer transformation on the shape of FIG. 11B is as follows.

(12)

Equations 11 and 12 become almost similar forms, and in practice, Equation 12 is applied when symmetry is possible.

The fourth step is freer conversion. The freer transformation is the relationship between the electric field component of the mask and the electric field component of the phase. But what we measure is the intensity of light that is proportional to the square of the magnitude of the electric field. So let's see what can happen if you create and use a mask in the form of light intensity. Two Functions Used in Equations 5 and 6 Wow Is expressed as a component of the electric field in the mask plane and the image plane, respectively. If we change the intensity of light to freer we can write

(13)

In Equation 13 Is a symbol for convolution and the light intensity of the mask Freer conversion means that the result of freer-converting electric field components is the result of linking each other. In other words, if we freer transform the intensity of the light, we get the result of converting the result we want.

Freer transform function If is symmetric about the origin, In the case of Eq. 5 and Eq. 6, we can write

(14)

Thus, if a function to freer transform is symmetric about the origin, the result is the same as the result of inverse freer transform. If the image symmetric with respect to the origin is freer transformed into a convex lens, it is the same as the result of inverse freer transformed.

Therefore, if the equation made symmetrically with respect to the origin is freer transformed, the shape of FIG.

12 is a side view of FIG. 5.

The fifth step is to remove negative numbers from the result of freezing. Masks can't represent negative numbers because they can display numbers in terms of light transmission. Therefore, the negative numbers shown in FIG. 12 should be removed.

With this concept, a phase mask can also be manufactured to express the result of the pre-transformation of a desired mask as a phase.

Lastly, a mask is fabricated using the pre-transformed pattern from which the negative number is removed. A mask can be produced on transparent flat plates, such as a film and glass. For example, the film mask preparation step of forming the mask by forming the pattern on the film will be described. In making the mask with negative numbers removed by the freer conversion, the most ideal condition is that the number of grades that can be expressed in black and white grade is very large, and that the spatial resolution of the film, that is, the shortest distance between adjacent points, is large. to be. In using a mask, the ability to expose a large area no less than the minimum line width is important. The factors affecting this are the spatial resolution and the number of black and white grades.

13 is a view for explaining the appearance of the pattern according to the black and white or color grade.

According to the number of black and white grades, the shape of the pattern to be finally obtained differs as shown in FIG. 13, and as the number of black and white grades increases, the shape of the corner becomes sharper.

It is also important to determine how many pixels to draw. For example, an optical system using a 2 inch lens and a mask having a size of 3 cm are used. If 3000 pixels are selected, the distance between the pixels is 10 microns. However, because the size of the pixel is related to the number of asa (ASA) of the film and cannot be infinitely small, the spacing between the pixels is approximately the same order of grain size as the film, and how large the size of the pixel is in the optical system. It is directly related to whether it can be implemented.

As a device used for producing such a film, a film recorder, a hologram recording device, or the like may be used.

Comparing the pre-converted pattern made through the above six steps and the original object is as follows.

14 is the shape of an object.

15 is a pattern diagram obtained by freezing.

The above has been a process of fabricating the freer transformed pattern used in the exposure apparatus of the present invention, and the operation principle of the exposure apparatus using the mask described above will be described with reference to FIGS. 16 and 17.

Fig. 16 is a view for explaining an exposure apparatus composed of one lens of the present invention.

When one lens is used, the distance between the pre-converted pattern 82 and the lens 83 is d, the focal length of the lens 83 is f, and the light ray 81 incident on the lens 83 is not parallel light. , The point light source (not shown) is separated by the distance z ₁ from the freer transformed pattern 82. The result of freer conversion through the lens 83 is as follows.

(15)

Next, in case of using two lens systems, a lens having a focal length f ₁ is placed, and a freer transformed pattern is placed at a position separated by the distance d behind the lens. The point light source lies at a position which becomes a distance z ₁ from this freer transformed pattern. The second lens having a focal length f ₂ is freer transformed at a distance z ₂ away from the first lens and a distance z ₃ away from the second lens. The shape of the freer transformed phase is as follows.

(16)

(17)

Equation 17 is the variables used in Equation 16.

Now consider the case of using three lenses.

17 is a view for explaining an exposure apparatus consisting of three lenses of the present invention.

Light rays 91 from the light source pass through the freer transformed pattern 92 and pass through the first lens 93 having a focal length of f1, followed by a focal length of the second lens 94 with a focal length of f2. At f3, the image passes through the third lens 95 and forms an image on the plane 96. The distance from the light source (not shown) to the free-converted pattern 92 is z ₁ , the distance between the first lens 93 and the second lens 94 is z _2, and the second lens 94 and the third lens are The distance of 95 is z ₃ and the distance of the free plane 96 from the third lens 95 is z ₄ . In the case of using three lenses, a freer transformed image is formed in the same manner as the result obtained by using one lens and two lenses. In FIG. 17, incident light is referred to as parallel light, and a distance d between the mask and the first lens is 0. FIG.

Up to now, the exposure system consisting of up to three lenses has been described, but there may be an exposure system using more lenses than this, and the resolution in the freer plane varies depending on the number of lenses. The following shows the resolution calculation method, which considers only the size in the x-axis direction in the two-dimensional plane (xy-plane) of the mask. This is because the magnitude in the y-axis direction can be considered in the same way.

(18)

Used in Equation 18 Is the length of the first zero in the x-axis direction when freer transforming a rectangular aperture.

18 is a graph of a line width in the x-axis direction according to z ₁ in FIG. 8.

If parallel light enters the mask In FIG. 10, the width in the x-axis direction is 20 It can be seen that

The freer transform is as follows.

The freer transformed pattern and the image on the PR have a freer conversion relationship, and the lens unit 50 performs freer conversion. The freer transformed pattern and the phase on the PR have the following characteristics from the freer transform relationship. Larger representations on the freer transformed patterns are smaller on the image on the PR and smaller representations on the PR image are on the image on the PR. As a result, if the spacing between pixels in the mask is small, it is represented as a large image on the PR. If the spacing between pixels in the mask is large, the image is represented as a small image on the PR. Therefore, black and white grades and pixel spacing are very important variables in the present invention and a suitable range of values can be obtained from computer simulation.

An exposure apparatus for patterning an arbitrary shape of the present invention to a nanometer level and a method of manufacturing a mask on which a freer transformed pattern is formed are not limited to the above-described embodiments, and various modifications are made within the range allowed by the technical idea of the present invention. You can do it.

According to an exposure apparatus for patterning an arbitrary shape of the present invention as described above and a mask forming method with a freer transformed pattern, the random shape is formed in the form of origin symmetry and the negative shape is performed after the freer conversion. By using a mask in which a pattern formed by freer conversion is removed by using a mask, a lens array for freer conversion is deformed in a conventional exposure apparatus, so that arbitrary shapes can be patterned to nanometer level, so that the equipment is inexpensive and operated. It is easy to change the pre-converted pattern only when manufacturing a new circuit, which not only lowers the cost of the chip during semiconductor processing but also facilitates research and production in all fields requiring nanometer processing. A mask formed with an exposure apparatus and a free-formed pattern for patterning an arbitrary shape to nanometer scale They provide a production method.

1 is an optical system diagram of a conventional exposure apparatus;

2 is a yearly graph of the trend of improving the minimum line width with respect to the wavelength of use of the optical system light source,

3 is a view for explaining a numerical aperture calculation formula of a lens;

4 is a diagram for explaining the principle of a convex lens used as a freer converter;

5 is a three-dimensional graph simulating the intensity distribution of the light free-converted at the focus position,

FIG. 6 is a three-dimensional graph simulating the distribution of intensity of freer transformed light at a distance that is half the focal length and the lens;

7 is a schematic optical system diagram of an exposure apparatus of the present invention;

8 is a figure of the shape to be finally made with the exposure apparatus of the present invention,

FIG. 9 is a diagram illustrating conversion data obtained by digitizing FIG. 8 to 0 and 1;

10A and 10B are diagrams illustrating two opposing objects for explaining a method of performing origin symmetry on digitized data.

11A and 11B are diagrams illustrating four facing objects for explaining a method of performing origin symmetry on digitized data;

12A and 12B are diagrams for explaining a method of removing an imaginary number using two masks in the result of freer conversion in the exposure apparatus of the present invention;

13 is a view for explaining the appearance of the pattern according to the black and white or color grade;

14 is the shape of an object,

15 is a pattern diagram free-transformed,

Fig. 16 is a view for explaining an exposure apparatus composed of one lens of the present invention.

17 is a view for explaining an exposure apparatus consisting of three lenses of the present invention;

FIG. 18 is a line width graph in the x-axis direction according to z ₁ of FIG. 8.

*** Explanation of symbols for the main parts of the drawing ***

11 light source 12 condenser

13: mask 14: front projection lens

15: rear projection lens 16: silicon wafer

20: light source unit 22: light source unit support

30: light source expansion unit 32: light source expansion unit support

34: vacuum pump 36: lens

37: space filter 39: vacuum pump port

40: mask portion 42: mask portion support

50 lens unit 52 lens unit support

54 lens 60 PR part

62: PR support base 70: optical bench

72: optical table 81: light beam

82: freer transformed pattern 83: lens

84: plane 91: rays

92: Freer transformed pattern 93: First lens

94: second lens 95: third lens

96: flat

Claims (10)

delete In the exposure apparatus, A light source unit having a lamp providing a light source; A mask unit having a mask formed with a pattern in which light passes through the light source unit, and an arbitrary shape is free of origin symmetry or a shape formed by origin, vertical and horizontal symmetry; A lens unit including one or several lenses for freer converting the light passing through the mask unit; A PR unit on which a wafer coated with PR is mounted; An exposure apparatus using a mask having a pattern formed by freer conversion, characterized in that it comprises a. The method of claim 2, And a color filter for extracting monochromatic light from said lamp, and a lens system and aperture for making said light source into parallel light when said light source is a monochromatic light source. The method of claim 2, An exposure apparatus installed between the light source and the mask unit and including a spatial filter and at least one lens and including a light source enlargement unit configured to output light having a predetermined cross-sectional area; . The method of claim 2, A part or all of the exposure apparatus is operated in a vacuum state, and further comprising an optical table for stably mounting the exposure apparatus and preventing external vibration. Exposure apparatus. delete The method of claim 2, The mask unit is included in the lens unit, and the mask provided in the mask unit and the first lens of the lens unit is in close contact with the exposure apparatus using a mask having a pattern formed free-transformed. Manufacturing an arbitrary shape using unit pixels having a constant size, Manufacturing a file for the arbitrary shape by digitizing the manufactured arbitrary shape part and other parts, Manufacturing an arbitrary shape file of symmetry including an original shape symmetry of the arbitrary shape file or any shape file corresponding to origin, vertical and horizontal symmetry, Pre-transforming any shape file of symmetry, and Removing negative numbers of the freer-converted file Method of producing a freer transformed pattern characterized in that it is produced, including. The method of claim 7, wherein And manufacturing a free-converted pattern on the transparent film or a substrate on which the free-converted pattern is formed on the substrate. The method according to claim 8 or 9, A mask manufactured using the method of manufacturing the pre-transformed pattern.