JP2011028233A - Photomask - Google Patents

Abstract

An object of the present invention is to provide a photomask capable of finely controlling a transmitted light amount distribution.
The present invention includes a substrate and a mask pattern layer formed on the substrate and having a fine dot pattern that is not resolved at an exposure wavelength, and the exposure is performed depending on the distribution state of the dot pattern. By providing a photomask for controlling a transmitted light amount distribution, wherein the dot pattern is configured by using ordered phase transmission, light shielding, and reverse phase transmission, To solve.
[Selection] Figure 1

Description

  In the present invention, the transmitted light amount distribution (exposure amount distribution) at the time of exposure is controlled by the distribution state of a pattern (hereinafter referred to as a dot pattern) composed of fine light transmitting portions and light shielding portions that are not resolved at the exposure wavelength. More specifically, the present invention relates to a photomask capable of finely controlling the transmitted light amount distribution.

  Conventionally, in an image sensor such as a CCD or a CMOS, a microlens is formed in each light receiving portion in order to increase the light collection efficiency of the light receiving portion. In such a microlens, conventionally, a resin portion formed on a device substrate is formed in a lens shape by heat flow. However, since the resin portion is formed into a lens shape by heat flow, it is difficult to form a lens having a desired focal length and good light collection efficiency.

  With respect to such a problem, in Patent Document 1, a resin structure having a pseudo lens shape is formed using a patterning mask whose transmittance is changed stepwise, and then the resin structure is A method of manufacturing a lens array that is deformed by heating is disclosed. This method uses a patterning mask to form a resin structure having a pseudo-lens shape, so that the molding accuracy can be improved somewhat. It has been difficult to form an efficient lens.

  In Patent Document 2, a photolithography mask including a mask substrate and a mask material formed on the mask substrate, the mask material being exposed to exposure light. A photolithographic mask configured to have a transmitted light amount distribution associated with a desired film thickness shape with respect to light is disclosed. This photolithography mask provides a transmitted light amount distribution corresponding to a desired three-dimensional shape only by exposure, but there has been little description on a method for reflecting a desired three-dimensional shape in a pattern.

  On the other hand, Patent Documents 3 to 5 disclose photomasks that control the transmitted light amount distribution during exposure according to the distribution state of fine dot patterns that are not resolved at the exposure wavelength. Since these photomasks have a fine dot pattern that is not resolved at the exposure wavelength, the dot on / off ratio is reflected on the workpiece as shades. Therefore, there is an advantage that the transmitted light amount distribution can be finely controlled. In these patent documents, a dither method and an error dispersion method are disclosed as dot pattern design methods.

JP-A-4-123004 JP-A-2-151862 JP 2002-31565 A Japanese Patent Laid-Open No. 2004-70087 JP 2005-258349 A

  Conventionally, there are known photomasks that control the distribution of transmitted light amount during exposure based on the distribution state of fine dot patterns that are not resolved at the exposure wavelength, but the dot patterns include two types of light transmission and light shielding. The component was used. Therefore, there is a problem that the transmitted light amount distribution cannot be sufficiently controlled.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a photomask capable of finely controlling the transmitted light amount distribution.

  In order to achieve the above object, as a result of intensive studies by the present inventors, it is possible to control the transmitted light amount distribution more finely by configuring the light transmission part of the dot pattern using rank phase transmission and reverse phase transmission. I found. The present invention has been made based on such knowledge.

  That is, in the present invention, the substrate has a mask pattern layer formed on the substrate and having a fine dot pattern that does not resolve at the exposure wavelength, and the transmission during exposure depends on the distribution state of the dot pattern. There is provided a photomask for controlling a light amount distribution, wherein the dot pattern is configured by using ordered phase transmission, light shielding, and reverse phase transmission.

  According to the present invention, the degree of freedom in controlling the transmitted light amount distribution is improved by further configuring the dot pattern using the reverse phase transmission in addition to the ordered phase transmission and the light shielding, and the transmitted light amount distribution is more finely controlled. It can be carried out. In particular, there is an advantage that a transmitted light amount distribution that realizes a steep light amount drop portion and gives a three-dimensional shape having steep uneven portions can be obtained.

  In the said invention, it is preferable that the reverse phase transmission part which performs the said reverse phase transmission is formed by digging in the said board | substrate. This is because the reverse phase transmission part can be easily formed.

  In the above invention, the dot pattern has an object unit area according to the target repeating unit of the object, and is configured using the rank phase transmission and the light shielding as the object unit area. It is preferable to use a rank phase unit region and an antiphase unit region configured using the antiphase transmission and the light shielding. This is because the dot pattern can be easily designed.

  In the above invention, it is preferable that the rank phase unit region and the antiphase unit region are each a rectangular unit region and arranged in a checkered pattern. This is because, for example, a transmitted light amount distribution useful for producing a microlens array can be obtained.

  In the above invention, the dot pattern has an object unit region according to the target repeating unit of the object, and the object unit region is configured using the rank phase transmission and the light shielding. Preferably, the reverse phase transmission dots are arranged at the boundary of the target unit area. This is because a steep drop in the amount of light at the boundary can be realized by disposing anti-phase transmission dots at the boundary of the object unit area that is the order phase unit area.

  In the above invention, the dot pattern has an object unit region according to the target repeating unit of the object, and the object unit region is configured using the reverse phase transmission and the light shielding. It is preferable that the rank-phase transmitting dots are arranged at the boundary portion of the object unit region. This is because a steep drop in the amount of light at the boundary can be realized by arranging the dots having the order phase transmission at the boundary of the object unit area which is the reverse phase unit area.

  In the said invention, it is preferable that a photomask is used for manufacture of a micro lens array. This is because by using the photomask of the present invention, a transmitted light amount distribution giving a three-dimensional shape having steep uneven portions can be obtained, and a microlens with higher light collection efficiency can be formed.

  Moreover, in this invention, it has the exposure process which exposes a to-be-processed member using the photomask mentioned above, and the image development process which develops the to-be-processed member after exposure, The manufacturing of the pattern formation body characterized by the above-mentioned Provide a method.

  According to the present invention, by using the above-described photomask, the transmitted light amount distribution can be controlled more finely. For example, a pattern forming body having a microlens array or the like having a higher light collection rate can be obtained. Can do.

  Further, the present invention is a pattern data production method for producing a photomask that controls the exposure amount (transmitted light amount) distribution during exposure according to the distribution state of fine dot patterns that are not resolved at the exposure wavelength. (A) Using the pattern formation plane of the photomask as the XY coordinates and using the coordinate values x and y as functions, the exposure amount (transmitted light amount) distribution at the time of desired exposure is expressed as the z value on the Z coordinate. The exposure amount (transmitted light amount) distribution grasping process and (b) the square root of the z value is selected so as to take a negative value, and the optical electric field distribution at the time of desired exposure is expressed as the z ′ value. Processing for grasping optical electric field distribution, and (c) a uniform illuminance on the photomask surface in exposure, and using a predetermined algorithm with reproducibility corresponding to z ′ value, X having a predetermined size that is not resolved at the exposure wavelength -Y coordinate area Provided is a pattern data generation method characterized by performing a dot pattern generation process for determining the arrangement of a dot pattern of the region size for each time.

  According to the present invention, pattern data in which the transmitted light amount distribution is more finely controlled can be obtained by performing the above-described optical electric field distribution grasping process.

  In the present invention, in addition to transmission and light shielding, the degree of freedom of control of the transmitted light amount distribution is improved and the transmitted light amount distribution is controlled more finely by configuring the dot pattern using reverse phase transmission. There is an effect that can be. In particular, it is possible to obtain a transmitted light amount distribution having a steep light amount drop portion that has been difficult in the past. By using the photomask of the present invention, a pattern forming body having a three-dimensional shape with steep uneven portions can be obtained.

It is a schematic sectional drawing which shows an example of the photomask of this invention. It is explanatory drawing explaining the difference between the photomask of this invention and the conventional photomask. It is a schematic plan view explaining the object unit area in the present invention. It is a schematic plan view explaining an example of the dot pattern in this invention. It is explanatory drawing explaining the photomask of this invention. It is a flow which shows an example of the preparation method of the pattern data of a dot pattern in this invention. It is a relationship figure which shows an example of the relationship between transmitted light quantity and a residual film thickness. It is explanatory drawing explaining the relationship between exposure amount distribution and optical electric field distribution in this invention. It is explanatory drawing explaining the relationship between exposure amount distribution and optical electric field distribution in this invention. It is explanatory drawing explaining preparation of the pattern data by an error dispersion method. It is a flowchart which shows an example of the error dispersion method in this invention. It is explanatory drawing explaining preparation of the pattern data by an error dispersion method. It is explanatory drawing explaining the error dispersion method in this invention. It is a complex plane showing the transmittance and phase of one dot. It is a schematic sectional drawing which shows an example of the manufacturing method of the photomask of this invention. It is a schematic sectional drawing explaining an example of the manufacturing method of the pattern formation body of this invention. It is a schematic sectional drawing explaining the other example of the manufacturing method of the pattern formation body of this invention. It is a pattern diagram which shows the pattern (binarization pattern) used in the Example.

  Hereinafter, the photomask of this invention and the manufacturing method of a pattern formation body are demonstrated in detail.

A. Photomask First, the photomask of the present invention will be described. The photomask of the present invention has a substrate and a mask pattern layer formed on the substrate and having a fine dot pattern that is not resolved at the exposure wavelength, and the transmission during exposure depends on the distribution state of the dot pattern. A photomask for controlling a light amount distribution, wherein the dot pattern is configured by using ordered phase transmission, light shielding, and reverse phase transmission.

  FIG. 1 is a schematic sectional view showing an example of the photomask of the present invention. The photomask shown in FIG. 1 has a substrate 1 and a mask pattern layer 2 formed on the substrate 1 and having a fine dot pattern that is not resolved at the exposure wavelength. Further, the dot pattern of the mask pattern layer 2 is configured by using the order phase transmission, the light shielding and the reverse phase transmission. Specifically, the light shielding unit 3, the order phase transmission unit 4 a, and the substrate 1 are arranged. An antiphase transmitting portion 4b formed by digging is formed.

  On the other hand, FIG. 2 shows a photomask according to the present invention (a photomask having a dot pattern configured using three types of order phase transmission, light shielding, and reverse phase transmission) and a conventional photomask (two types of transmission and light shielding). It is explanatory drawing explaining the difference with the photomask which has the dot pattern comprised using.

  As shown in FIG. 2A, the conventional photomask 11 forms the dot pattern of the mask pattern layer 2 using transmission and light shielding, and the light transmission part 4 and the light shielding part 3 are formed. Yes. When the conventional photomask 11 is irradiated with the light 5, a part of the light 5 passes through the light transmission part 4, thereby causing an optical electric field distribution (superposition of peaks having gentle skirts) as shown in FIG. ) Occurs. In general, the transmitted light amount distribution is proportional to the square of the optical electric field distribution, and as a result, a transmitted light amount distribution as shown in FIG. 2C is obtained.

  On the other hand, as shown in FIG. 2D, the photomask 10 of the present invention forms the dot pattern of the mask pattern layer 2 using the ordered phase transmission, the light shielding, and the antiphase transmission, A transmission part 4a, a light shielding part 3, and an antiphase transmission part 4b are formed. Similarly to the above, when the photomask 10 of the present invention is irradiated with the light 5, a part of the light 5 passes through the rank phase transmission part 4 a and the antiphase transmission part 4 b, as shown in FIG. An optical electric field distribution (superposition of peaks with gentle skirts) occurs. At this time, the light 5 that has passed through the rank phase transmission part 4a and the light 5 that has passed through the reverse phase transmission part 4b have phases opposite to each other, and therefore can cancel each other. As a result, FIG. As shown in f), it is possible to obtain a transmitted light amount distribution that gives a three-dimensional shape having steep uneven portions as compared with a transmitted light amount distribution of a conventional photomask. Thus, by constructing the dot pattern using the antiphase, the transmitted light amount distribution can be controlled more finely.

Thus, according to the present invention, the degree of freedom in controlling the transmitted light amount distribution is improved by configuring the dot pattern using the reverse phase transmission in addition to the ordered phase transmission and the light shielding, and the transmitted light amount distribution is improved. More precise control can be performed. In particular, there is an advantage that a transmitted light amount distribution giving a three-dimensional shape having steep uneven portions can be obtained.
Hereinafter, the photomask of the present invention will be described for each configuration.

1. Mask Pattern Layer First, the mask pattern layer used in the present invention will be described. The mask pattern layer used in the present invention is formed on a substrate described later and has a fine dot pattern that is not resolved at the exposure wavelength. Furthermore, in the present invention, the dot pattern is configured using rank phase transmission, light shielding, and reverse phase transmission. In the present invention, “reverse phase transmission” refers to transmission of light that gives a phase opposite to the phase of phase transmission (for example, phase difference π). Note that the phase difference between the rank phase transmission and the antiphase transmission is usually πrad (180 °) and its vicinity (180 ° ± 15 °).

(1) Dot pattern The dot pattern in the present invention is not particularly limited as long as it is configured using rank phase transmission, light shielding, and reverse phase transmission. As an example of the dot pattern in the present invention, it has an object unit area according to the target repeating unit of the object, and the object unit area is configured by using the above-described rank phase transmission and the light shielding. And the one using the reverse phase unit region formed by using the reverse phase transmission and the light shielding.

  In this case, the entire dot pattern is configured by using a combination of two types of unit areas, that is, a rank phase unit area and an antiphase unit area. Each unit area of the rank phase unit area and the antiphase unit area is configured using transmission and shading, so the dot pattern in each unit area is designed by the conventional dither method, error dispersion method, etc. can do. Therefore, the dot pattern can be easily designed. In addition, by using the dot pattern, it is possible to form a transmitted light amount distribution having a steep light amount drop portion at the boundary between the rank phase unit region and the antiphase unit region.

  The “object unit region” is a unit region that forms a dot pattern, and is a unit region that is appropriately set according to the repetition unit of the target object. For example, when the object is a microlens array, the object unit region 21 is set according to the repeating unit of the microlens 20, as shown in FIG. The shape of the object unit region is not particularly limited, and examples thereof include a rectangular shape such as a square and a rectangle, and a circular shape.

  Further, the rank phase unit area is a unit area configured using the rank phase transmission and light shielding, and the antiphase unit area is a unit area configured using the antiphase transmission and light shielding. Each of the rank phase unit region and the antiphase unit region has a binarized dot pattern. This dot pattern may be a dot pattern in which dots of the same size are used and the density thereof is changed, or a dot pattern using dots of different sizes. Examples of such a dot pattern design method include halftone dots (area modulation) in printing, a dither method, and an error dispersion method. An example of a specific design method for the dot pattern is the method described in Japanese Patent Application Laid-Open No. 2004-70087.

  In particular, in the present invention, it is preferable that the rank phase unit region and the antiphase unit region are each a rectangular unit region and arranged in a checkered pattern. This is because, for example, a transmitted light amount distribution useful for producing a microlens array can be obtained. As such a dot pattern, specifically, as shown in FIG. 4, a rank phase unit region A configured using rank phase transmission and light shielding, and a reverse phase configured using reverse phase transmission and light shielding. A dot pattern in which the unit regions B are arranged in a checkered pattern can be given. With this dot pattern, it is possible to form a transmitted light amount distribution having a steep light amount drop portion at the boundary between the rank phase unit region A and the antiphase unit region B.

  Next, another example of the dot pattern in the present invention will be described. As another example of the dot pattern, it has an object unit area according to the target repeating unit of the object, and the object unit area is configured using the rank phase transmission and the light shielding. The phase-phase unit region is a region in which the dots having the reverse phase transmission are arranged at the boundary of the object unit region. By disposing anti-phase transmission dots at the boundary of the target unit area, which is the order phase unit area, it is possible to realize a steep light amount drop portion at the boundary. The object unit area is an antiphase unit area configured using the antiphase transmission and the light shielding, and the rank phase transmission dots are arranged at a boundary portion of the object unit area. Also good. In this case, a steep light amount drop portion can be realized at the boundary portion by arranging the dots of the rank phase transmission at the boundary portion of the object unit region which is the antiphase unit region. The “dot” means a minimum unit constituting a dot pattern. In the present invention, there are usually three types of dots, that is, a phase phase transmission dot, an antiphase transmission dot, and a light shielding dot. Moreover, the boundary part in this invention is located in the edge part of a target object unit area | region, Although the width | variety of a boundary part is not specifically limited, For example, in the range of 1 dot-3 dots, especially 1 It is preferably within the range of dots to 2 dots. By arranging the light transmissive part in the opposite phase to the dot pattern in the dot pattern of the object unit area excluding the boundary part as a dot at the boundary part of such a width, it is steep in the vicinity of the boundary part. It is possible to realize a dip portion with a sufficient amount of light.

  In the present invention, a plurality of object unit areas (preferably, all object unit areas) are the rank phase areas, and the opposite phase transmission dots are formed at the boundary of the object unit areas. It is preferable that they are arranged. Similarly, a plurality of object unit areas (preferably, all object unit areas) are the opposite phase areas, and the rank phase transmission dots are arranged at the boundary of the object unit areas. It is preferable. This is because a transmitted light amount distribution having a steep light amount drop portion can be formed at the boundary between adjacent object unit regions.

  Here, in FIG. 3, the object unit region 21 is set according to the repeating unit of the microlens 20. The object unit region 21 in FIG. 3 is rectangular, and realizes a dot pattern that forms a transmitted light amount distribution having a steep light amount drop portion at a boundary portion along the side of the rectangle. In the present invention, the transmitted light amount distribution on the rectangular side when anti-phase transmission is not used is a transmission having a gentle valley shape as shown in FIG. The light intensity distribution. By disposing a minute dot pattern with reverse phase transmission that is not resolved at the exposure wavelength in such a portion, a desired steep light amount drop portion can be formed. Specifically, by digging the substrate like the antiphase transmitting portion 4b in FIG. 5A, the light of the antiphase transmitted through the antiphase transmitting portion 4b is added as shown in FIG. 5B. Thus, the light of the order phase transmitted through the order phase transmitting portion 4a cancels out, and a steep light amount drop portion shown in FIG. 5C can be formed. A specific example of a photomask having such a dot pattern will be described later with reference to FIG.

  Although the example of the microlens has been described above, the present invention can also be applied to the design of the dot pattern other than the microlens by setting the object unit region and the boundary portion according to the object. For example, in a Frennel lens, an object unit region is a region concentrically divided, and in a blazed diffraction grating, an object unit region is one of a plurality of rectangles arranged in a stripe shape. Further, the boundary portion is set corresponding to a region to which a steep uneven shape is given in the object unit region. Further, the object unit region may have a shape change in the product. For example, in the case of a microlens array, the central lens and the peripheral lens of the microlens array are designed with different shapes to optimize the light collection efficiency. Also changes.

  Next, the dot pattern in the present invention will be described in more detail. The dot pattern in the present invention needs to be so fine as not to be resolved at the exposure wavelength. Specifically, the resolution R of the exposure apparatus (stepper) is calculated as R = K × λ / NA where λ nm is the exposure wavelength, NA is the numerical aperture of the lens, and K is a process (determined by resist, development, etc.) constant. The When the exposure wavelength λ is 365 nm of i-line, the numerical aperture NA is 0.7, and the process constant is 0.5, the resolution R is 260 nm, and the dot pattern on the pattern forming body described later needs to be smaller than 260 nm. The exposure apparatus normally performs 1/4 reduction exposure, and the dot size (diameter) on the photomask is 1040 nm or less as a condition for fine dots. On the other hand, the size of a rectangle that can be formed by a photomask drawing apparatus is limited to about 200 nm. That is, the size of fine dots that can be practically used on the photomask is in the range of 200 nm to 1040 nm. On the other hand, in order to express gradation of a 4 μm square lens with dither, it is necessary to make at least 20 horizontal and vertical divisions. Become. Therefore, the preferable size of the fine dots is 200 nm to 800 nm on the photomask, and 50 nm to 200 nm on the pattern forming body described later. That is, the size of each dot (rectangle) of a dot pattern (for example, a dot pattern shown in FIG. 18 described later) is 50 to 260 nm, preferably 50 to 200 nm on a pattern forming body described later.

  An example of a method for forming a dot pattern with a dot size in the above range is to divide the target area into a grid with the selected dot size as the pitch, and to shade, rank phase transmission, and antiphase transmission dots according to the position of the grid A typical method is to arrange (typically, a light shielding part, a rank phase transmission part, and an antiphase transmission part are arranged inside the grating). The pitch of the grid is usually selected to be constant, but in order to more accurately realize the three-dimensional shape (that is, the transmitted light amount distribution), the fine dot size range at the center and the peripheral part (boundary part) of the object unit area The pitch of the grating may be changed.

(2) Others The material of the mask pattern layer used in the present invention is not particularly limited as long as the above-described dot pattern can be formed and has a desired light shielding property. For example, Cr and Cr alloy, etc. Can be mentioned. Further, the thickness of the mask pattern layer varies depending on the material of the mask pattern layer, and is, for example, in the range of 300 mm to 2000 mm.

2. Substrate Next, the substrate used in the present invention will be described. The substrate used in the present invention supports the mask pattern layer described above. The substrate used in the present invention is not particularly limited as long as it has a desired transparency to the light used in exposure, and the same substrate as that of a general photomask substrate is used. be able to. Examples of such substrates include inflexible transparent rigid materials such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plates; and flexibility such as transparent resin films and optical resin plates. A transparent flexible material etc. can be mentioned. Further, the thickness of the substrate used in the present invention is not particularly limited, and is preferably selected as appropriate according to the use of the photomask of the present invention.

3. Photomask The photomask of the present invention is a photomask that controls the distribution of transmitted light amount at the time of exposure according to the distribution state of fine dot patterns that are not resolved at the exposure wavelength. It is configured using phase transmission.

  In addition, the photomask of the present invention has a reverse phase transmission portion that performs reverse phase transmission. The reverse phase transmission part in the present invention is not particularly limited as long as it can transmit light having a phase opposite to the order phase transmission. Especially, in this invention, it is preferable that an antiphase transmission part is formed by digging a board | substrate. This is because the reverse phase transmission part can be easily formed. The depth of digging the substrate is normally set as appropriate so that the phases of light passing through the rank phase transmission part and the antiphase transmission part are reversed. Another method for realizing the anti-phase transmission part can be realized by laminating a transparent layer having a high refractive index on the target light transmission part, and a method realized by SOG (spin-on-glass) has been well known. Yes.

  The photomask of the present invention is preferably used for manufacturing an optical member. Specific examples of the optical member include a microlens array, a Frennel lens, a nanoimprint template, a blazed diffraction grating, and a reflector.

In addition, a method for producing pattern data of a dot pattern in the present invention will be described with reference to FIG.
A photosensitive resist material (also simply referred to as a resist) for obtaining a desired residual film thickness profile after development and an exposure wavelength for exposing the photosensitive resist material are determined in advance (S1, S2).
First, a predetermined photosensitive resist material is applied onto a substrate equivalent to a substrate for forming a residual film thickness profile after a predetermined development, and an area of a predetermined size is exposed and developed with various exposure amounts ( S3), the relationship data between the exposure amount and the residual film thickness of the resist is obtained (S4). The relational data between the exposure amount and the remaining resist film thickness may be expressed as mathematical data.
When a negative resist is used as the photosensitive resist material, the relationship between the amount of transmitted light (exposure amount) and the remaining film thickness is generally proportional as shown in FIG.
In FIG. 7, the transmitted light amount (exposure amount) and the remaining film thickness are also normalized.
Depending on the resist image after development, the relationship between the exposure amount and the remaining film thickness varies depending on the size and density of the pattern, so it is necessary to incorporate several types of data corresponding to the size and density of the pattern. . Specifically, a photomask having a region in which a predetermined number of gradations are stepwise configured by a flat mesh pattern is manufactured, and the photosensitive resist material used for the lens forming material is exposed using the manufactured photomask. The relationship between the white area ratio (that is, the amount of transmitted light) of the photomask flat mesh pattern and the thickness of the photosensitive resist material is measured by developing and measuring the change in the thickness of the photosensitive resist material at each gradation. The relational data between the exposure amount and the residual film thickness of the resist by the method for obtaining the tone curve is preferable from the viewpoint of reproducibility in manufacturing the product.
In addition, if the remaining film thickness characteristics with respect to the exposure amount of the photosensitive resist material for obtaining the desired residual film thickness profile after development are known in advance, the exposure amount and the remaining film thickness each time. It is not always necessary to obtain relational data.

Next, using the relationship data between the exposure amount and the residual film thickness of the resist, the exposure amount distribution of the photomask pattern corresponding to the desired profile (S5) of the workpiece is obtained (S7).
A series of processing from S3 to S5 to S7, or from S6 to S7 is exposure amount (transmitted light amount) distribution grasping processing.
The photomask pattern formation plane is taken as an XY coordinate, and the exposure value distribution is expressed as a z value on the Z coordinate by using the coordinate values x and y as a function.
Here, the exposure amount (transmitted light amount) distribution is represented as z = F (x, y).
On the other hand, the size of the pattern area (that is, the dot size) of the photomask that is not resolved at the determined exposure wavelength is determined to be a predetermined size (S8).
Here, let the determined predetermined sizes be the X-direction width a and the Y-direction width a.
As mentioned earlier, in addition to optical resolution depending on the exposure wavelength, expression of the desired residual film thickness profile of the resist after development, and restrictions on the performance of the lithography tool used for photomask production are taken into consideration. And decide.

  Next, from the exposure dose distribution z = F (x, y) of the photomask pattern, the optical electric field distribution z ′ = F ′ (x, y) of the photomask pattern that matches the desired profile (S5) of the workpiece. ) Is obtained (S7 ′). Since the exposure amount distribution z is the square of the optical electric field distribution z ′, the optical electric field distribution z ′ can take either positive or negative values.

Here, FIG. 8A shows the cross-sectional shape of the exposure dose distribution for obtaining the microlens. Since the exposure amount distribution z is the square of the absolute value of the optical electric field distribution z ′, the optical electric field distribution can take either positive or negative values as shown in FIG. In the present invention, it is preferable to select so that the gradient of the optical electric field distribution changes smoothly. This is particularly suitable for dithering in the present invention, and as a result, it is easy to obtain an exposure amount distribution having a steep shape. For example, in FIG. 8 (c), a tangential line at the boundary portion of the optical field distribution of the left and the T ₁ as the center of the optical field distribution, the negative side having an angle smaller tangent and T ₁ ( It is preferable to select a distribution on the minus side. Similarly, the tangent at the boundary of the central optical field distribution in the case of a T ₂ are, as a right of the optical field distribution, the distribution of positive (+ side) of the angle has a small tangential and T ₂ It is preferable to select.

On the other hand, FIG. 9A shows the cross-sectional shape of the exposure dose distribution for obtaining a blazed diffraction grating. As shown in FIG. 9B, the optical electric field distribution can take either positive or negative values. In FIG. 9 (c), and a tangential line at the boundary portion of the optical field distribution of the left and the T ₁ as the center of the optical field distribution, the negative side having an angle smaller tangent and T ₁ (- side ) Distribution is preferred. Similarly, the tangent at the boundary of the central optical field distribution in the case of a T ₂ are, as a right of the optical field distribution, the distribution of positive (+ side) of the angle has a small tangential and T ₂ It is preferable to select. In order to smoothly change the slope of the optical electric field distribution, it is preferable to select so that the rate of change of the slope, that is, the second-order derivative of z ′ becomes small. In the present invention, as described in FIGS. 8C and 9C, it is preferable that the optical electric field distribution is alternately formed between positive and negative.

Next, a predetermined reproducible algorithm (S9) is used from the obtained relational data of z ′ = F ′ (x, y) and the size of the pattern area that is not resolved at the determined exposure wavelength. A dot pattern of a predetermined size that is not resolved at the exposure wavelength is determined for each region divided into the size on the XY coordinates (S10).
Examples of the predetermined algorithm include an error dispersion method and an ordered dither method.
Based on this determination, a CAD tool creates a pattern data by arranging a dot pattern at a predetermined position on the XY coordinates (S11).
A series of processes from S9 to S11 described above is a dot pattern generation process.
In this way, pattern data can be produced.

Here, the case where the error dispersion method is applied to the production of the pattern data will be described with reference to the numerical example of the optical electric field distribution in FIG. 10 and the flowchart of the error diffusion method in the present invention in FIG.
FIG. 10A is a diagram corresponding to the optical electric field distribution of FIG. 8C and is expressed by normalizing the optical electric field distribution intensity from −1.0 to +1.0. The horizontal axis indicates the position, the section in which the optical electric field distribution changes from +1.0 to −1.0 is divided into 10 equal parts, and numbers 1 to 11 are assigned in order as the assigned position numbers. At position number 1, the optical electric field strength is +1.0, and the optical electric field strength decreases in the order of the numbers. At position number 6, the optical electric field strength is 0.0, and after position number 7, the optical electric field strength is a negative value. As an example, the optical field intensity is -1.0 at position number 11. The position number and the value of the optical electric field strength in this example are described in the column (row) of the position number and the optical electric field strength A in the table of FIG. In the case of a photomask, a light transmittance that is an amount corresponding to the optical electric field intensity is further obtained.

  Next, the case of applying the error dispersion method to the production of pattern data necessary for the photomask will be described with reference to the flowchart of FIG. The conventional error diffusion method aims to minimize the local average error between the original image and the binarized image, and binarizes the original pixel value every time the original image is binarized (quantized). The difference (error) of the processed pixel values is added to the unprocessed pixels near the target pixel by adding weights corresponding to the distance and positional relationship between the pixels, and adjacent pixels are sequentially fixed while diffusing the error. It is a method of binarization by the threshold value. Such an existing error diffusion method is limited to a positive pixel value, and cannot be applied to a case where a negative value is also included like the optical electric field intensity in the present invention. The present invention is characterized in that the quantization process is extended so that a desired result can be obtained even when a negative pixel value is included. Here, in order to simplify the description, the processing for one-dimensional pixel value data will be described.

  First, in step S21, a new processing pixel (pixel value A) of the original image is acquired. Specifically, 1.00 is obtained as the optical electric field strength A corresponding to the position number 1 in the table of FIG. Next, in step S22, the pixel value A and the integration error R are added to obtain an accumulated pixel value B. Specifically, since the accumulated error R corresponding to the position number 1 in the table is 0 as an initial value, the accumulated pixel value B is 1.00.

  Next, in step S23, if the accumulated pixel value B is greater than or equal to the threshold T1 and less than or equal to 1.0 as the quantization process, the quantization result D is 1, and if the accumulated pixel value B is smaller than the threshold T1 and greater than the threshold T2, the quantization is performed. If the result D is 0 and the accumulated pixel value is less than or equal to the threshold T2 and greater than −1.0, the quantization result D is quantized to −1 (corresponding to a phase difference of 180 degrees). In the example of the table of FIG. 10B, since the accumulated pixel value B at the pixel position 1 is 1.00, the quantization result D is 1. Here, the threshold T1 is set to 0.50 and the threshold T2 is set to −0.50. However, in order to handle a negative pixel value, a negative threshold −0.5 is newly introduced in quantization, and (1, 0, −1 ). The setting of the threshold T1 and the threshold T2 is related to the appearance frequency of 1 and −1 of the quantization result D. For example, if T1 is 0.33 and T2 is −0.33, the quantization result D is 1 and −1. Increases frequency of appearance. Therefore, these threshold values T1 and T2 may be adjusted according to the property of the application target.

  Next, in step S24, a quantization error E is calculated by subtracting the quantization result D from the accumulated pixel value B. In the table of FIG. 10B, the quantization error E corresponding to the pixel position 1 is 0.0, which is obtained by subtracting the quantization result 1 from the accumulated pixel value 1.0.

  Next, in step S25, the quantization error E is weighted and added to neighboring pixels according to the positional relationship of the pixels, and error diffusion processing is performed by calculating an integrated error R for each pixel. To do. In the table of FIG. 10B, since one-dimensional pattern data is handled as an example, the quantization error E is added to the integrated error R of the next adjacent pixel as it is. In the table of FIG. 10B, the quantization error E (value 0.0) at the position number 1 is added to the accumulated error R of the pixel at the adjacent position number 2 as it is, and the value of the accumulated error R is 0. .0. On the other hand, in the case of two-dimensional pattern data, an error diffusion process is performed by weighting and adding a quantization error E corresponding to the positional relationship of the pixels to neighboring pixels that have not been quantized. An example will be described separately.

  Thus, a series of error diffusion processing is completed, and it is checked whether there is a pixel to be further processed. When further processing is performed, the process returns to step S21 to acquire a new processing pixel of the original image. In the example of the table of FIG. 10B, 0.95 is acquired as the optical electric field intensity A at position number 2, and the processing from step S22 to step S26 is repeated in the same manner as described above.

  In the example of the table of FIG. 10B, when the process from step S22 to step S26 is repeated for the pixel value 0.95 of the optical electric field intensity A at position number 2, the cumulative pixel value B is 0.95, 3 1 is obtained as the quantization result D, and -0.05 is obtained as the quantization error E. The quantization error E is added to the adjacent pixel to be processed next, that is, the accumulated error R of the position number 3, and the accumulated error R becomes −0.05. Further, when the process from step S22 to step S26 is repeated for the pixel value 0.81 of the optical electric field intensity A at the position number 3, the cumulative error R-0.05 is added to the optical electric field intensity A0.81, and the cumulative pixel. The value B is 0.76, and the ternarization result D is 1 and the quantization error E is -0.24. The quantization error E is added to the next pixel to be processed next, that is, the accumulated error R of the position number 4, and the accumulated error R of the position number 4 becomes −0.24.

  Similarly, the optical electric field strengths A (1.00, 0.95, 0.81, 0.59, 0.31, 0.00, −0.31, −0. 59, -0.81, -0.59, -1.00), if the dither processing by ternarization including negative is continued, the ternarization result D corresponding to each value is obtained. (1, 1, 1, 0, 1, 0, -1, 0, -1, -1, -1) is obtained. The result of this ternarization is shown in FIG. In the figure, the upper side shows the normalized optical electric field intensity, the negative side shows the normalized optical electric field intensity with a phase of 180 degrees, and the value on the central axis shows the optical electric field intensity is 0, that is, the light is shielded. The ternarization results are indicated by bar graphs corresponding to the position numbers 1 to 11. In this example, the optical field strengths are positive values of 0.59 and 0.31 at position numbers 4 and 5, the electric field strength is 0.00 at position number 6, and −0.31 and −0 at position numbers 7 and 8. .59, a negative value, and the light energy intensity (light quantity) is proportional to the square of the optical electric field intensity (0.35, 0.10, 0.00, 0.10, 0.35), and the light quantity drops. Has a part. Corresponding to this, the result of ternarization is (0, 1, 0, −1, 0). On the photomask, 1 is light transmission, 0 is light shielding, and −1 is light transmission with a phase of 180 degrees. A good light amount drop portion (light-shielding portion) is formed at the position 6 due to the effect of the phase difference.

  Here, for comparison, FIG. 12 shows a numerical example in which dither processing by the error diffusion method based on binarization is performed with the optical electric field strength set to a positive value based on the conventional technique for the same light quantity distribution. Similar to the example of FIG. 10 already described, the optical electric field strength A corresponding to the position numbers 1 to 11 is shown in the tables of FIGS. 12 (a) and 12 (b). In the conventional example, the optical electric field intensity A is (1.00, 0.95, 0.81, 0.59, 0.31, 0.00, 0.31, as shown in the table of FIG. 0.59, 0.81, 0.95, 1.00) and positive values. The result of performing dither processing by the error diffusion method based on the conventional binarization with respect to the optical electric field intensity A having a positive value corresponds to each optical electric field intensity A (1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1). In this conventional example, the optical electric field strength is 0.59, 0.31, 0.00, 0.31, 0.59 and positive values at position numbers 4, 5, 6, 7, and 8, and the optical energy intensity ( The light intensity is proportional to the square of the optical electric field intensity (0.35, 0.10, 0.00, 0.10, 0.35), and the light energy intensity (light quantity) is an embodiment of the present invention. It is the same value as FIG. In the conventional example, the result of binarization processing by the error diffusion method corresponding to the position numbers 4, 5, 6, 7, and 8 is (0, 1, 0, 0, 1), and the position number 6 on the photomask. , 7 has a light-shielding portion, but positions No. 5 and 8 have a light transmission portion of a rank phase. As a result, the light transmitted through the light transmitting portions at position numbers 5 and 8 spreads around and enters the light amount drop portion (light shielding portion) at position number 6 to reduce the light shielding effect, which is not preferable.

A case where the error dispersion method is applied to the production of two-dimensional pattern data will be described with reference to FIG.
For example, the horizontal direction of the table is the vertical direction as the X direction and the Y direction, and cells (also referred to as pixels, which are sizes corresponding to the pitch) are provided at predetermined pitches, and each cell is as shown in FIG. When the values are arranged, the following processing is sequentially performed from the upper left to the lower right of the table.
First, for the upper left cell P0, for example, -0.33 and 0.33 are set as threshold values, and ternarization is performed (FIG. 13B).
The value -0.8 of the upper left cell P0 becomes -1 by ternarization.
Next, weighted addition (or subtraction) is performed on the cells adjacent to the cell P0, as shown in FIG.
In FIG. 13B, numbers 1, 2, and 3 surrounded by circles (circled numbers) indicate adjacent cells to be weighted (or subtracted) from the cell P0 and their values.
Next, the process moves to the adjacent cell P1, and ternarization and weighted addition (or subtraction) are performed to obtain FIG.
Further, the process moves to the cell P2 next to it, and similarly, ternarization and weighted addition (or subtraction) are performed to obtain FIG.
Thereafter, the same processing is sequentially performed on each cell in the direction of the arrow in FIG. 13E, and the obtained result is obtained. In the above description, as shown in FIG. 13A, the processing is sequentially performed from the upper left to the lower right of the table. However, the present invention is not limited to this.

  Next, using the pattern data in which the dot patterns are arranged as described above, the resist on the light-shielding layer of the photomask substrate is exposed and drawn with an electron beam drawing exposure apparatus (S12). A photomask (S13) of the present invention is manufactured through process processes such as development and etching.

  As described above, it is effective to obtain the relationship between the exposure amount and the remaining film thickness in accordance with the pattern of the resist image after development to be produced, but it is not practical when there are many types to be obtained. Therefore, there is also a method of matching the pattern of the developed resist image to be produced using simulation (S6).

In the present invention, a method for producing pattern data as described above can be provided. That is,
A pattern data production method for producing a photomask for controlling an exposure amount (transmitted light amount) distribution at the time of exposure according to a distribution state of fine dot patterns not resolved at an exposure wavelength,
(A) Exposure in which the pattern formation plane of the photomask is an XY coordinate, and the exposure value (transmitted light amount) distribution at the time of desired exposure is expressed as a z value on the Z coordinate using the coordinate values x and y as a function. Amount (transmitted light amount) distribution grasp processing,
(B) an optical electric field distribution grasping process in which at least one of the square roots of the z value is selected to take a negative value, and the optical electric field distribution at the time of desired exposure is expressed as a z ′ value;
(C) In the exposure, the illuminance is uniform on the photomask surface, and a predetermined algorithm having reproducibility is used corresponding to the z ′ value for each region of XY coordinates of a predetermined size that is not resolved at the exposure wavelength. , Dot pattern generation processing for determining the arrangement of the dot pattern of the area size,
It is possible to provide a pattern data producing method characterized by performing the above.
Furthermore, in the present invention, it is possible to provide a photomask or hologram manufacturing process characterized by having a pattern data preparation method for performing the pattern data preparation method.

  Further, when the transmittance and phase of one dot are expressed in a complex plane, it is expressed as Texp (jθ) like a point tn in FIG. The distance T from the origin represents the transmittance, and the angle θ from the real axis represents the phase. Since the transmittance is usually 1 or less, T is also 1 or less, and the dot tn exists in a region within a radius 1 from the origin in the complex plane. Since the dot pattern in the present invention is configured using the ordered phase transmission, the light shielding, and the reverse phase transmission, as shown in FIG. 14B, ta = 1 (ranked phase transmission), tb = 0 ( It is expressed by light shielding) and tc = -1 (reverse phase transmission). In the present invention, semi-transmission may be used in addition to rank phase transmission, light shielding, and reverse phase transmission. In this case, in FIG. 14B, a point is provided at a position that is on the real axis and whose distance from the origin is less than 1. By adding one or two or more such points (referred to as representative values of quantization), the expression of the transmitted light amount distribution is further enriched. In addition, for example, when an error dispersion method is applied, a dot pattern can be easily produced by providing a threshold value in consideration of semi-transmission. Furthermore, in the present invention, the expression of the transmitted light amount distribution can be further enriched by appropriately adjusting and combining the phase and transmittance. Specifically, as shown in FIG. 14C, one or more points (representative values of quantization) may be provided in an arbitrary region of a circle having a radius of 1 from the origin of the complex plane. Also in this case, the expression of the transmitted light amount distribution can be further enriched as compared with the conventional case. For example, it can be used as a specific method for realizing a computer generated hologram.

  In FIG. 14C, ta = 1 (rank phase transmission), tb = 0 (light shielding), tc = exp (j2π / 3) (phase 120 ° transmission), td = exp (j4π / 3) (phase 240 °) The complex transmittance of the pixel is quantized with the four representative values given in (Transmission). To explain the quantization process in step S23 of FIG. 11, the distances between the accumulated pixel value B (complex transmittance) and the four representative values ta, tb, tc, and td are sequentially compared, and the distance is the largest. Let the near representative value be the quantization result D (complex transmittance). Further, the quantization error E in step S24 is a complex number obtained by subtracting the quantization result D from the accumulated pixel value B. By the way, the distance between the accumulated pixel value B and the four representative values is usually compared by the Euclidean distance. In the specific example of FIG. 14C, the value in the region a is a region within a circle having a radius of 1 from the origin. The representative value ta, the value in the region b are quantized to the representative value tb, the value in the region c is quantized to the representative value tc, and the value in the region d is quantized to the representative value td. Such region division according to the proximity of the distance from the representative value (also referred to as a mother point) is called Voronoi division. Further, a method for realizing dots corresponding to four representative values with a photomask having a light shielding layer on the surface of the transparent substrate is as follows. Ta (rank phase transmission) removes the light shielding layer and exposes the transparent substrate to reduce the transmittance to 1. Tb (light shielding) leaves the light shielding layer and the transmittance is 0, and tc (phase 120 ° transmission) is a depth at which the phase difference of light becomes 120 ° by digging the transparent substrate after removing the light shielding layer, The td (phase 240 ° transmission) is realized by removing the light shielding layer and then digging the transparent substrate so that the phase difference of the light becomes 240 °.

  Moreover, the manufacturing method of the photomask of this invention will not be specifically limited if it is a method which can obtain the photomask mentioned above. FIG. 15 is a schematic cross-sectional view showing an example of the photomask manufacturing method of the present invention. First, an overall mask layer 2a made of Cr is formed on the substrate 1 by sputtering or vacuum evaporation (FIG. 15A). Next, a full resist layer 6 made of a photosensitive resin is formed on the full mask layer 2a (FIG. 15B). Next, electron beam drawing is performed based on the dot pattern, and then development is performed, thereby removing the resist in the portions where the rank phase transmission part and the antiphase transmission part are to be formed, thereby forming the resist pattern layer 6a (FIG. 15). (C)). Next, the exposed entire mask layer 2a is removed by etching (reactive ion etching) 7 using Cl gas or the like (FIG. 15D). Next, the remaining resist pattern layer 6a is removed to obtain a photomask intermediate 12 (FIG. 15E).

Next, an entire resist layer 6 made of a photosensitive resin is formed again on the obtained mask pattern layer 2 (FIG. 15F). Next, electron beam drawing is performed based on the dot pattern, and thereafter development is performed to remove the resist in the portion where the antiphase transmitting portion is to be formed, and the resist pattern layer 6a is formed (FIG. 15G). Next, the exposed substrate 1 is dug by etching (reactive ion etching) 7 using CF ₄ gas or the like (FIG. 15H). Finally, by removing the remaining resist pattern layer 6a, it is possible to obtain the photomask 10 having the light shielding portion 3, the rank phase transmission portion 4a, and the reverse phase transmission portion 4b (FIG. 15 (i)). Note that the photomask 10 is configured using the rank phase unit region A configured using the phase-phase transmitting unit 4a and the light-shielding unit 3, the reverse-phase transmitting unit 4b, and the light-shielding unit 3 as in FIG. 4 described above. And an antiphase unit region B.

B. Next, the manufacturing method of the pattern formation body of this invention is demonstrated. The method for producing a pattern formed body of the present invention comprises an exposure step of exposing a member to be processed using the photomask described above, and a developing step of developing the member to be processed after exposure. It is.

  FIG. 16 is a schematic cross-sectional view for explaining an example of the method for producing a pattern-formed body of the present invention. In the method of manufacturing the pattern forming body shown in FIG. 16, first, the above-described photomask 10 and the processing member 33 having the base 31 and the photosensitive resin layer 32 are prepared, and the light 5 is transmitted through the photomask 10. Irradiation is performed to expose the photosensitive resin layer 32 (FIG. 16A). Thereby, a three-dimensional latent image 34 of the microlens is obtained inside the photosensitive resin layer 32 (FIG. 16B). Next, by developing the exposed photosensitive resin layer 32, a pattern forming body 36 having microlenses 35 is obtained (FIG. 16C). When the negative type is used as the photosensitive resin layer 32, the photomask 10 has the order phase unit region A and the antiphase unit region B, and therefore the phase difference at the boundary portion (the boundary portion between the two microlenses 35). As a result, the light cancels each other out, the exposure amount drops steeply, an unexposed portion is formed at a corresponding position of the photosensitive resin layer 32, and a pattern forming body 36 having a steeply depressed portion 37 is obtained.

  FIG. 17 is a schematic cross-sectional view showing another example of the method for producing a pattern-formed body of the present invention. More specifically, an example in which the dot pattern as shown in FIG. 5 is applied to a photomask for a microlens array is shown. The photomask 10 in FIG. 17A has a mask pattern layer 2 having a fine dot pattern that is not resolved at the exposure wavelength on the surface of a transparent substrate 1. Regions A and B in FIG. 17A are object unit regions corresponding to individual microlenses. Here, in the example of FIG. 16, A is a rank phase unit region and B is an antiphase unit region, and a steep light amount drop portion is realized at the boundary portion. In the example of FIG. 17, both the A region and the B region are realized. The phase-phase unit region is newly arranged at the boundary, and a reverse-phase unit region that is not resolved at the exposure wavelength of reverse-phase transmission is arranged to realize a steep light amount drop portion. By exposing and developing the negative photosensitive resin layer of the pattern forming body through such a photomask, a lens shape having a steep depression 37 at the boundary as shown in FIG. A pattern forming body 36 having the resin layer 35 is obtained.

  In the embodiment of FIG. 17A, the size of the fine dots of the reverse phase transmission part 4b is the same as that of the fine dots of the order phase transmission part 4a, and is a size that does not resolve at the exposure wavelength. Further, the dot pattern in FIG. 17A shows a schematic configuration in which the light shielding portions 3 and the order phase transmitting portions 4a are alternately arranged except for the antiphase transmitting portion 4b arranged at the boundary portion. As a dot pattern for actually forming a lens, dots are distributed two-dimensionally as illustrated in FIG. When the blacked out portion is used as the light shielding portion, the dot distribution in FIG. 18 is a transmitted light amount distribution in which the light amount decreases at the center of the region, which is an example of forming a convex lens in the positive resist. On the contrary, if the portion painted black is used as the light transmission portion, this is an example in which a convex lens is formed on the negative resist.

  As described above, according to the present invention, by using the above-described photomask, the transmitted light amount distribution can be controlled more finely. For example, the peripheral portion of the lens can be used for condensing and more condensing efficiency. It is possible to obtain a pattern forming body having a microlens array and the like excellent in the above.

1. Exposure process The exposure process in this invention is a process of exposing a to-be-processed member using a photomask. The photomask used in the present invention is the same as the contents described in the above “A. Photomask”, and therefore description thereof is omitted here.

The member to be treated used in the present invention usually has a photosensitive resin layer. The photosensitive resin used for the photosensitive resin layer may be a general photosensitive resin, and may be a positive photosensitive resin or a negative photosensitive resin. Examples of the positive photosensitive resin include phenol epoxy resin, acrylic resin, polyimide, and cycloolefin. Specific examples include IP3500 (manufactured by TOK), PFI27 (manufactured by Sumitomo Chemical), and ZEP7000 (manufactured by Zeon). On the other hand, examples of the negative photosensitive resin include an acrylic resin. Specific examples include polyglycidyl methacrylate (PGMA), chemically amplified SAL601 (manufactured by Shipley Co., Ltd.), and the like.
Although it does not specifically limit as thickness of the said photosensitive resin layer, For example, it exists in the range of 10 nm-10 micrometers.

  Moreover, a to-be-processed member has a base | substrate holding a photosensitive resin layer normally. It is preferable that the substrate used in the present invention is appropriately selected according to the type of the target pattern forming body.

  The wavelength of light used for exposure is not particularly limited, but is preferably in the range of, for example, 100 nm to 500 nm, and more preferably in the range of 250 nm to 450 nm. Examples of the light source used in the present invention include an excimer lamp and a mercury lamp.

2. Development Step The development step in the present invention is a step of developing the processed member after exposure. In the case where the photosensitive resin used is a positive photosensitive resin, more photosensitive resin is removed in a region where the exposure amount is larger. On the other hand, when the photosensitive resin used is a negative photosensitive resin, more photosensitive resin is removed as the exposure amount is smaller.

  Examples of the method for developing the processed member after exposure include a method using a developer. A general developer can be used as the type of the developer, but it is preferable to select appropriately according to the type of the photosensitive resin. Specific examples of the developer include alkali developers such as tetramethylammonium aqueous solution, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution and sodium carbonate aqueous solution, and acids such as hydrochloric acid aqueous solution, acetic acid aqueous solution, sulfuric acid aqueous solution and phosphoric acid aqueous solution. A developing solution etc. can be mentioned.

3. Pattern-formed body Examples of the pattern-formed body obtained by the present invention include a substrate with a microlens array, a Fresnel lens, a template for nanoimprint, a substrate with a blazed diffraction grating, and a reflector. Furthermore, if reactive ion etching (also called reactive ion etching) is performed in a gas atmosphere in which both the resin layer and the substrate can be corroded from the patterned photosensitive resin layer side, anisotropic etching is performed. You can also duplicate the pattern on top (called etchback).

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example]
An electron beam drawing resist ZEP7000 (manufactured by ZEON Co., Ltd.) was applied to a thickness of 300 nm on a 6-inch quartz substrate having a Cr film, and electron beam drawing was performed based on the pattern (binarized pattern) shown in FIG. . This pattern is produced using the error dispersion method described in Japanese Patent Application Laid-Open No. 2004-70087. Next, the electron beam drawing resist was developed with a developer for ZEP7000 to obtain a resist pattern layer in which object unit regions (11 μm × 11 μm) of the pattern shown in FIG. 18 were periodically formed vertically and horizontally. Subsequently, using a reactive ion etching apparatus, dry etching was performed with Cl gas through the resist pattern layer to remove the exposed Cr film.

Next, an electron beam drawing resist ZEP7000 (manufactured by Zeon) was applied again to the surface of the etched Cr film with a film thickness of 300 nm, and alignment drawing was performed using an electron beam drawing machine. At this time, electron beam drawing was performed only on the object unit region forming the antiphase unit region B so as to obtain a dot pattern as shown in FIG. Next, the electron beam drawing resist was developed with a developer for ZEP7000 to obtain a resist pattern layer. Subsequently, using a reactive ion etching apparatus, CF ₄ gas was used for dry etching through the resist pattern layer to dig out the exposed quartz substrate. Finally, the remaining resist pattern layer was peeled off to obtain a photomask of the present invention.

  In the obtained photomask, the target unit area where the quartz substrate was not dug and the target unit area where the quartz substrate was dug were formed in a checkered pattern.

  Using the obtained photomask, the Si wafer coated with photosensitive resin IP3500 (manufactured by TOK) was exposed with an i-line stepper, and then developed. In this photomask, the phases are opposite in adjacent object unit regions, so that the light cancels out at the boundary. Therefore, a resist shape having a steep depression at the boundary between adjacent object unit regions was obtained.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... Mask pattern layer 2a ... Whole surface mask layer 3 ... Light-shielding part 4 ... Light transmission part 4a ... Order phase transmission part 4b ... Reverse phase transmission part 5 ... Light 6 ... Whole surface resist layer 6a ... Resist pattern layer 7 ... Etching DESCRIPTION OF SYMBOLS 10 ... Photomask of this invention 11 ... Conventional photomask 12 ... Photomask intermediate body 20 ... Micro lens 21 ... Object unit area | region 31 ... Base | substrate 32 ... Photosensitive resin layer 33 ... Processing member 34 ... Latent image 35 ... Micro lens 36 ... pattern forming body 37 ... steep depression

Claims (9)

A photomask that includes a substrate and a mask pattern layer that is formed on the substrate and has a fine dot pattern that is not resolved at an exposure wavelength, and controls a distribution of transmitted light amount during exposure according to a distribution state of the dot pattern Because
The photomask according to claim 1, wherein the dot pattern is configured using ordered phase transmission, light shielding, and reverse phase transmission.   2. The photomask according to claim 1, wherein the reverse phase transmission portion that performs the reverse phase transmission is formed by digging the substrate. The dot pattern has an object unit area according to the repetition unit of the target object,
As the object unit area, a rank phase unit area configured using the rank phase transmission and the light shielding, and an antiphase unit area configured using the reverse phase transmission and the light shielding are used. The photomask according to claim 1 or 2.   4. The photomask according to claim 3, wherein the rank phase unit region and the antiphase unit region are each a rectangular unit region and are arranged in a checkered pattern. The dot pattern has an object unit area according to the repetition unit of the target object,
The object unit region is a rank phase unit region configured using the rank phase transmission and the light shielding,
3. The photomask according to claim 1, wherein the reverse phase transmission dots are arranged at a boundary portion of the object unit region. 4. The dot pattern has an object unit area according to the repetition unit of the target object,
The object unit region is an antiphase unit region configured using the antiphase transmission and the light shielding,
3. The photomask according to claim 1, wherein the rank phase transmission dots are arranged at a boundary portion of the object unit region. 4.   The photomask according to any one of claims 1 to 6, wherein the photomask is used for manufacturing a microlens array.   A pattern forming body comprising: an exposure step of exposing a member to be processed using the photomask according to claim 1; and a developing step of developing the member to be processed after exposure. Production method. A pattern data production method for producing a photomask for controlling an exposure amount (transmitted light amount) distribution at the time of exposure according to a distribution state of fine dot patterns not resolved at an exposure wavelength,
(A) Exposure in which the pattern formation plane of the photomask is an XY coordinate, and the exposure value (transmitted light amount) distribution at the time of desired exposure is expressed as a z value on the Z coordinate using the coordinate values x and y as a function. Amount (transmitted light amount) distribution grasp processing,
(B) an optical electric field distribution grasping process in which at least one of the square roots of the z value is selected to take a negative value, and the optical electric field distribution at the time of desired exposure is expressed as a z ′ value;
(C) In the exposure, the illuminance is uniform on the photomask surface, and a predetermined algorithm having reproducibility is used corresponding to the z ′ value for each region of XY coordinates of a predetermined size that is not resolved at the exposure wavelength. , Dot pattern generation processing for determining the arrangement of the dot pattern of the area size,
A method for producing pattern data, characterized in that:

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