JP5169796B2 - Pattern forming method and imprint mold manufacturing method - Google Patents

Description

  The present invention relates to a pattern forming method by multiple exposure and a method for producing an imprint mold.

  In imprint lithography, an imprint mold is pressed to transfer a concavo-convex mold pattern formed in a pattern area on the surface of an imprint mold onto a transfer object. The mold pattern is formed on the imprint mold substrate by lithography, dry etching, or the like.

  When a plurality of convex portions repeatedly arranged at regular intervals in the vertical and horizontal directions are transferred to an object to be transferred, the imprint mold is provided with a mold pattern having a plurality of concave portions repeatedly arranged at regular intervals in the vertical and horizontal directions. It is possible to form a resist pattern corresponding to a mold pattern by repeatedly drawing a rectangular or circular unit figure corresponding to one recess on a resist film using a pattern generator using an electron beam or a laser beam. is there. However, when the pattern area where the mold pattern is formed becomes large, the drawing time by the pattern generator becomes very long, which is not practical.

  If an optical reduction projection exposure apparatus is used, a mask pattern provided on an exposure mask can be reduced and projected, and a resist pattern can be drawn in a short time on a resist film applied to the substrate surface. The mask pattern of the exposure mask has a plurality of unit figures repeatedly arranged at regular intervals in the vertical and horizontal directions corresponding to the mold pattern. The exposure amount is set to an appropriate exposure amount at which a plurality of resist images of a resist pattern corresponding to a plurality of unit figures are formed with desired dimensions.

  When a pattern is repeatedly transferred to a transfer area over almost the entire surface of a transfer object having a diameter of about 200 mm by imprint lithography, the pattern area of the imprint mold used also has a large area corresponding to the transfer area. However, the exposure area that can be exposed with the exposure mask is smaller than the entire pattern area. Therefore, the exposure mask is provided with a mask pattern corresponding to a part of the mold pattern, and exposure is performed by sequentially moving the rectangular exposure areas so as to be adjacent to each other in the pattern area. Each exposure area is exposed using an appropriate exposure amount.

  When the size of the unit figure is close to the wavelength of the exposure light, the resist image of the formed resist pattern undergoes dimensional variation depending on the pattern density due to the optical proximity effect. In particular, there is no figure to be exposed outside the pattern area on the substrate. For this reason, the pattern density is reduced at the outer periphery of the pattern region. The resist image formed on the outer periphery of the pattern region has an effective exposure amount lower than the resist image at the center of the resist pattern due to the effect of the optical proximity effect. As a result, there is a problem that the resist image formed on the outer peripheral portion of the pattern region is reduced in size or not resolved.

  A graphic correction method for correcting a decrease in exposure amount for a resist image formed on the outer periphery of a pattern region having a low pattern density has been proposed (see Patent Document 1). In the proposed figure correction method, the effective exposure amount is calculated in consideration of the optical proximity effect, and the unit figure size on the exposure mask corresponding to the resist image in which the effective exposure amount decreases is increased.

  When the pattern region on the substrate is formed by connecting a plurality of exposure regions, the effective exposure amount increases in the vicinity of the boundary (side) between the adjacent exposure regions. When the resist image is an aperture graphic, two resist images facing each other across the boundary between exposure regions are connected. Further, four resist images facing each other are connected at the corners of the four adjacent exposure regions. In such a case, graphic correction may be performed to reduce the size of the unit graphic of the exposure mask so as to reduce the effective exposure amount.

In this way, the dimensions of the unit graphic arranged on the outer periphery of the exposure mask corresponding to each exposure area are corrected in consideration of the presence or absence of adjacent exposure areas on the four sides of each rectangular exposure area. As described above, the dimensional variation of the resist pattern to be formed can be suppressed by the figure correction method.
Japanese Patent No. 3334441

  However, it is necessary to use a plurality of exposure masks having mask patterns subjected to different graphic corrections depending on the position of the exposure region within the pattern region. When the pattern area is divided by the exposure area of 2 rows and 2 columns, four types of exposure masks are required. Further, when the pattern area is divided into exposure areas of 3 rows and 3 columns or more, nine types of exposure masks are necessary. When the graphic correction method is employed, a plurality of exposure masks are required, and the efficiency of exposure decreases with the replacement of the plurality of exposure masks, resulting in an increase in manufacturing cost.

  It is also possible to divide the mask pattern arrangement area of the exposure mask and arrange a plurality of mask patterns subjected to different graphic corrections on one exposure mask. Each of the plurality of mask patterns is formed in the corresponding exposure region. In that case, the area of each of the plurality of exposure regions that divide the pattern region on the substrate is reduced. Therefore, there arises a problem that the exposure area increases and the time of the exposure process becomes long. In addition, an increase in the boundary between exposure areas causes a problem that the number of unit graphics to be corrected increases.

  An object of the present invention is to provide a pattern forming method and an imprint mold manufacturing method capable of reducing dimensional variation and suppressing an increase in cost.

  According to the first aspect of the present invention, (b) a step of applying a resist film on the substrate, and (b) arranging a plurality of first exposure sections adjacent to each other in a pattern region defined on the substrate. (C) a first sequential exposure of the mask pattern to the resist film in each of the first exposure sections with a first exposure amount over the entire surface of the pattern area; and (d) the same size as the first exposure section. A plurality of second exposure sections are arranged, and the second exposure section is at least one of the row direction and the column direction with respect to the first exposure section at an arbitrary integer multiple of the width corresponding to the pitch of the repeated figure included in the mask pattern. And (e) a mask pattern with respect to the resist film in each of the second exposure sections at a second exposure amount over an area wider than the pattern area. And (f) a step of forming a drawn image on the resist film by development, and (g) a total of the first and second exposure amounts is formed with a desired size within the pattern region. There is provided a pattern forming method for achieving an appropriate exposure amount and an insufficient exposure amount at which a drawn image is not formed outside the pattern region.

  According to the second aspect of the present invention, (b) a step of applying a resist film on the substrate, and (b) arranging a plurality of first exposure sections adjacent to each other in a pattern region defined on the substrate. In other words, the first pattern section is created by sequentially exposing the mask pattern to the resist film of each of the first exposure sections with the first exposure amount over the entire surface of the pattern area, and having the same size as the first exposure section. A plurality of second exposure sections are arranged, and the second exposure section is shifted in at least one of the row direction and the column direction with respect to the first exposure section by an arbitrary integer multiple of the width corresponding to the pitch of the repeated figure included in the mask pattern. The mask pattern is sequentially exposed to the resist film in each of the second exposure sections with a second exposure amount over a region wider than the pattern region. And (c) forming N (N is an integer of 2 or more) pattern sections that partially overlap each other, and (d) forming a drawn image on the resist film by development. (E) each included in each of the N pattern sections, where Dm is a limit exposure amount at which a drawn image is formed and Do is an appropriate exposure amount at which the drawn image is formed with a desired dimension. An exposure section is sequentially exposed with an exposure amount of Do / N, and a pattern forming method is provided in which N satisfies a relationship of N <1 / (1-Dm / Do).

  According to the third aspect of the present invention, (b) a step of applying a resist film on the substrate, and (b) arranging a plurality of first exposure sections adjacent to each other in a pattern region defined on the substrate. Step, sequentially exposing the mask pattern to the resist film of each of the first exposure sections with the first exposure amount over the entire surface of the pattern area, and arranging a plurality of second exposure sections having the same size as the first exposure sections The second exposure section is shifted in at least one of the row direction and the column direction with respect to the first exposure section at an arbitrary integer multiple of the width corresponding to the pitch of the repeated figure included in the mask pattern so as to partially overlap each other. A step of exposing the mask pattern to the resist film in each of the second exposure sections at a second exposure amount over a region wider than the pattern region, and a step of developing. Forming a resist pattern on the resist film by the step of forming a drawn image on the strike film, and (c) selectively removing the substrate using the resist pattern as a mask. Provided is a method for manufacturing an imprint mold in which the total is an appropriate exposure amount at which a drawn image is formed with a desired dimension within a pattern region, and an insufficient exposure amount at which a drawn image is not formed outside the pattern region. .

According to the fourth aspect of the present invention, (a) a step of applying a resist film on the substrate, and (b) arranging a plurality of first exposure sections adjacent to each other in a pattern region defined on the substrate. In other words, the first pattern section is created by sequentially exposing the mask pattern to the resist film of each of the first exposure sections with the first exposure amount over the entire surface of the pattern area, and having the same size as the first exposure section. A plurality of second exposure sections are arranged, and the second exposure section is shifted in at least one of the row direction and the column direction with respect to the first exposure section by an arbitrary integer multiple of the width corresponding to the pitch of the repeated figure included in the mask pattern. The mask pattern is sequentially exposed to the resist film in each of the second exposure sections with a second exposure amount over a region wider than the pattern region. A resist pattern on the resist film by creating N pattern sections (N is an integer of 2 or more) that partially overlap each other, and forming a drawn image on the resist film by development. And (c) selectively removing the substrate using the resist pattern as a mask, and (d) the limit exposure amount at which a drawn image is formed is Dm, and the drawn image has a desired dimension. With Do as the appropriate exposure amount formed in step S, each exposure section included in each of the N pattern sections is sequentially exposed with an exposure amount of Do / N, where N is N <1 / (1-Dm / Do). A method of manufacturing an imprint mold that satisfies the relationship is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the pattern formation method which can reduce the fluctuation | variation of a dimension, and can suppress the increase in cost, and the manufacturing method of the mold for imprint.

  As shown in FIG. 7, when the area that can be exposed by the mask pattern 22 (see FIG. 4) of the exposure mask is smaller than the pattern area 12, the pattern area 12 is divided by a plurality of exposure sections 16 and step-and-repeat method. To sequentially expose. Each of the plurality of exposure sections 16 is disposed adjacent to each other. In FIG. 7, the arrangement of 2 rows and 2 columns is shown as the plurality of exposure sections 16, but the number of divisions and the arrangement of the exposure sections 16 are not limited. The pattern area 12 may be a figure obtained by connecting a plurality of rectangles, for example, a cross. The number and arrangement of the exposure sections 16 are determined based on the dimensions of the pattern region 12 and the mask pattern 22.

  As shown in FIGS. 8 and 9, the exposure apparatus is used to sequentially expose the mask pattern 22 to each of the plurality of exposure sections 16 defined in the pattern region 12 by the step-and-repeat method, and then to the substrate 10. The positive resist film 30 applied on the surface is developed to form a plurality of drawn images 34. As the exposure amount, an appropriate exposure amount at which the drawn image 34 is formed with a desired dimension by resolution is used at the center of each exposure section 16. The drawn image 34 is a part of the opening pattern provided in the resist film 30 that is repeatedly arranged in the row direction and the column direction at the pitch Pr corresponding to the opening 24 of the mask pattern 22 shown in FIG.

  The plurality of drawn images 34 are formed on the positive resist film 30, but can also be applied to a negative resist film. When using a negative resist film, the resist film exposed to the exposure light transmitted through the opening 24 of the mask pattern 22 remains on the substrate surface as a columnar resist film after development. Further, the planar pattern of the drawn image 34 is circular as shown in FIG. When the exposure condition is close to the resolution limit, the square opening 24 of the mask pattern 22 is a circle or a square with rounded corners. It is also possible to obtain a substantially square drawn image by adjusting the exposure conditions.

  When each of the plurality of exposure sections 16 arranged adjacent to each other is sequentially exposed with an appropriate exposure amount, a drawn image formed in the peripheral area of the exposure section 16 may deviate from a desired size range due to the effect of the optical proximity effect. is there.

  As shown in FIG. 10, the pattern density in the vicinity is small in the peripheral region of the isolated side that is not adjacent to the other exposure sections 16. Therefore, in the peripheral region of the isolated side, a defective drawing image 34a having an opening size smaller than the lower limit of the desired size range, or a defective drawing image 34b in which a recess is formed in the resist film 30 without being resolved is formed. Further, in the Levenson-type phase shift mask pattern, as shown in FIG. 11, the Levenson-type phase shift mask pattern is individually formed in a peripheral area of a side adjacent to another exposure section 16 at a position facing the boundary of the exposure section 16. The defective drawing images 34c and 34d in which two drawing images are combined or four are combined are formed. When the exposure amount is reduced, a defective drawing image (not shown) having an opening size larger than the upper limit of a desired size range may be formed in the peripheral region adjacent to the other exposure section 16. Note that the occurrence of a defective drawing image in the peripheral region of the side adjacent to the other exposure section 16 is hardly generated in the binary mask pattern and small in the halftone phase shift mask pattern.

  Here, the defective drawing images 34 a, 34 b, 34 c and 34 d are generated only in the peripheral area of the exposure section 16, and are not generated in the central portion of the exposure section 16. Note that the defective drawing images 34 a to 34 d shown in FIGS. 10 and 11 are generated in the peripheral region of the range of one row and one column along the side of the exposure section 16. However, there are cases where the defective drawing image extends over several rows and columns in the peripheral area where the defective drawing images 34a to 34d occur.

(Embodiment of the present invention)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

    In the pattern forming method according to the embodiment of the present invention, first openings 24 (see FIG. 4) as unit figures respectively correspond to the rectangular mask patterns 22 repeatedly arranged in the row direction and the column direction at a constant pitch. The second exposure sections 16 and 18 (see FIG. 12) are set so as to overlap each other by shifting in the row direction and the column direction by an arbitrary integral multiple of the pitch. Although the pitch in the row direction and the pitch in the column direction may be different, the following description will be made assuming that both are the same. First and second pattern sections 2, 4 (see FIG. 13) are created in which the first and second exposure sections 16, 18 set in this way are arranged adjacent to each other. The first pattern section 2 is made to correspond to the pattern area 12 (see FIG. 1) of the substrate 10 onto which the mask pattern 22 is transferred, and the second pattern section 4 is set so as to cover the entire surface of the pattern area 12. The sum of the exposure amounts of the first and second exposure sections is an appropriate exposure amount in which the drawn image 34 of the resist film 30 is formed in a desired dimension by resolution in the pattern region 12, and is drawn outside the pattern region 12. The mask pattern 22 is sequentially exposed to all the first and second exposure sections 16 and 18 so that the image becomes an insufficient exposure amount that is not formed by unresolving.

  The pattern forming method according to the embodiment can be applied to the manufacture of an imprint mold. The imprint mold used for the description of the embodiment has a pattern region 12 on the surface of the substrate 10 as shown in FIG. Patterns such as pillars and holes are arranged in the pattern region 12. For example, as shown in FIGS. 2 and 3, a plurality of concave transfer patterns 14 are repeatedly arranged on the surface of the substrate 10 in the row direction and the column direction at a constant pitch Pm. The pattern shape may be concave or convex with respect to the surface of the substrate 10. Further, the pattern pitch and aspect ratio (the value of the ratio of the groove depth to the opening width) are not limited and are arbitrary.

In the case of optical imprint lithography, as the substrate 10, for example, transparent materials such as quartz glass having a thickness of about 6 mm to 7 mm, heat-resistant glass, calcium fluoride (CaF ₂ ), and magnesium fluoride (MgF ₂ ), and these transparent materials A laminated structure of materials is used. In the case of thermal imprint lithography, silicon carbide (SiC), Si, SiC / Si, silicon oxide (SiO ₂ ) / Si, silicon nitride (Si ₃ N ₄ ) / Si, or the like is used as the substrate 10. Further, a metal substrate such as tantalum (Ta), aluminum (Al), titanium (Ti), and tungsten (W) may be used.

  The transfer pattern 14 is formed in the pattern region 12 on the surface of the substrate 10 by photolithography, dry etching, or the like. In the photolithography process, the mask pattern of the exposure mask is sequentially exposed onto the resist film applied to the surface of the substrate 10 using, for example, an optical reduction projection exposure apparatus or the like.

  The exposure mask used for exposure of the resist film includes a rectangular mask pattern 22 as shown in FIGS. The mask pattern 22 has a plurality of square openings (unit figures) 24 formed in a light shielding film 26 made of chromium (Cr) or the like formed on the surface of a transparent substrate 20 such as synthetic quartz. The openings 24 are repeatedly arranged in the row direction and the column direction at a constant pitch Pg. Although the plurality of openings 24 are arranged in 6 rows and 6 columns as the mask pattern 22, the number of the plurality of openings 24 arranged is not limited. In a normal mask pattern, thousands to tens of thousands of openings are arranged in the row direction and the column direction, respectively.

  In the description of the embodiment, as shown in FIG. 4, a binary type exposure mask is used, but a Levenson type or halftone type phase shift exposure mask may be used. The phase shift exposure mask can improve the resolution of the exposure apparatus determined by the exposure wavelength and the numerical aperture, and can accurately draw a fine pattern. For example, as shown in FIG. 6, the Levenson type phase shift exposure mask includes an opening (first figure) 24A and an opening (second figure) 24B that shifts the exposure light by π radians with respect to the opening 24A in the row direction. And mask patterns 22a arranged alternately adjacent to each other in the column direction. In the Levenson type phase shift exposure mask, the openings 24A and 24B are unit figures.

  In the pattern forming method according to the embodiment, as shown in FIG. 12, a plurality of exposure sections corresponding to the mask pattern 22 shown in FIG. 4, for example, the first exposure section 16 and the same size as the first exposure section 16. The second exposure sections 18 have a width (k × Pr) (k is an arbitrary integer) that is an integer multiple of the pitch Pr (see FIG. 8) corresponding to the pitch Pg (see FIG. 4) of the openings 24. Shifted in the row and column directions. The first and second exposure sections 16 and 18 are set so as to partially overlap each other.

As shown in FIG. 13, a plurality of first exposure sections 16a, 16b, 16c, and 16d are arranged adjacent to each other to create a first pattern section 2. The first pattern section 2 is made to correspond to the pattern area 12 shown in FIG. A plurality of second exposure sections 18a, 18b, 18c, 18d, 18e, 18f, 18g, 18h, and 18i are arranged adjacent to each other to create the second pattern section 4. The second pattern section 4 is set so as to cover the first pattern section 2. Here, the first and second exposure sections 16a to 16d and 18a to 18i are shifted from each other in the row direction and the column direction by a width (k × Pr) that is an integer multiple of the pitch Pr.

  Thereafter, the mask pattern 22 is applied to each of the first exposure sections 16a to 16d and the second exposure sections 18a to 18i set in the resist film applied to the surface of the substrate 10 by an exposure apparatus. Sequential exposure is performed with an exposure amount of. The first pattern section 2 corresponding to the pattern area 12 is double-exposed, and the second pattern section 4 set outside the pattern area 12 is single-exposed. Therefore, in the pattern region 12, the total exposure amount becomes an appropriate exposure amount that resolves the drawn image of the resist film with a desired dimension. In the area where the second pattern section 4 is set outside the pattern area 12, the exposure amount is ½ of the appropriate exposure amount, which is an insufficient exposure amount.

  Here, the appropriate exposure amount is Do, and the limit exposure amount at which the drawn image of the resist film 30 is resolved is Dm. Usually, in order to avoid resist residues, the ratio Dm / Do between the limit exposure dose Dm and the appropriate exposure dose Do is in the range of about 0.6 to about 0.85. Therefore, in the area where the second pattern section 4 that is not subjected to double exposure is set outside the pattern area 12, exposure is performed with an exposure amount less than the limit exposure amount Dm, and thus a drawn image is not formed on the resist film 30. As a result, the resist film is developed, and the drawn image 34 shown in FIG.

  As shown in FIG. 12, the first and second exposure sections 16 and 18 are shifted from each other by approximately half the width of the first exposure section 16, but the shifted width is not limited. For example, as shown in FIG. 14, the first and second exposure sections 16 and 18 may be shifted from each other by a width A that is approximately ½ or less of the first exposure section 16. However, the width A is an arbitrary integral multiple of the pitch Pr (k × Pr), and the exposure section is set so that the drawing images corresponding to the defective drawing images 34a to 34d shown in FIGS. 10 and 11 do not overlap each other. It is necessary to make it larger than the width B of the peripheral region 50, that is, satisfy the relationship of A ≧ B.

  For example, the peripheral area of the side not adjacent to the other exposure section 16 shown in FIG. 10 depends on the pattern density, and the effective exposure amount (Do−Δa) is smaller than the appropriate exposure amount Do at the center of the exposure section 16. ). That is, underexposure of Δa occurs. Since the pattern density in the peripheral area of the side adjacent to the other exposure sections 16 is the same as the central portion of the exposure section 16, the effective exposure amount is about the same as the appropriate exposure amount. In the embodiment, each of the first and second exposure sections 16a to 16d and 18a to 18i is exposed with an exposure amount Do / 2. The peripheral area of the isolated side of the first pattern section 2 corresponding to the pattern area 12 does not overlap with the peripheral area of the isolated side of the second pattern section 4. Therefore, in the peripheral region of the isolated side of the first pattern section 2, the underexposure amount is Δa / 2. As described above, it is possible to reduce the underexposure in the peripheral region of the isolated side, and to suppress the dimensional variation of the drawn image 34 of the resist film 30.

  On the other hand, the Levenson-type phase shift mask pattern has an inherent problem that the peripheral area of the side adjacent to the other exposure section 16 shown in FIG. 11 is overexposed. For example, the peripheral area of the side adjacent to the other exposure sections 16 is exposed with an effective exposure amount (Do + Δb) that is larger than the appropriate exposure amount Do. In the embodiment, each of the first and second exposure sections 16a to 16d and 18a to 18i is exposed with an exposure amount Do / 2. Therefore, the effective overexposure amount is Δb / 2 in the peripheral region adjacent to the other exposure sections 16, and therefore, the combination of the drawn images to be formed and the increase in the aperture size are suppressed. Furthermore, the same effect is confirmed also in the peripheral region in the vicinity of the intersection position of the mutually orthogonal sides of the first exposure sections 16a to 16d and the second exposure sections 18a to 18i. As described above, by performing exposure with a lower exposure dose Do / 2 compared to the conventional case, it is possible to suppress the dimensional variation of the drawn image 34 inherent to the Levenson-type phase shift method.

  Next, a method for manufacturing an imprint mold to which the pattern forming method according to the embodiment is applied will be described with reference to FIGS. The exposure mask used for pattern formation is the Levenson type phase shift exposure mask shown in FIG. In the mask pattern 22a of the Levenson type phase shift exposure mask, openings 24A and 24B which are unit figures are arranged. Actually, square openings 24A and 24B each having a side of 1.25 μm are arranged at a pitch of 2.5 μm and 6000 rows and 6000 columns. As the exposure apparatus, a reduction projection exposure apparatus having a reduction ratio of 5 to 1 is used. Further, the first pattern section 2 and the second pattern section 4 shown in FIG. 13 are prepared in advance. The first exposure sections 16a to 16d and the second exposure sections 18a to 18i are shifted in the row direction and the column direction by 3000 times the pitch. Each of the first and second exposure sections 16a to 16d and 18a to 18i is a square having a side of 3 mm.

As shown in FIG. 15, a resist film 30 is applied to the surface of a substrate 10 such as a quartz substrate with a thickness of about 400 nm. As the resist film 30, a positive resist film containing a novolac resin as a main material is used. The resist film used has an appropriate exposure dose Do of 320 mJ / cm ² and a limit exposure dose Dm of 240 mJ / cm ² . The resist film 30 is pre-baked at about 130 ° C. for about 60 seconds after coating.

As shown in FIG. 16, for each of the first exposure sections 16a to 16d of the first pattern section 2 corresponding to the pattern area 12 shown in FIG. 1, the mask pattern 22a is ½ of the appropriate exposure amount Do. Sequential exposure is performed at an exposure amount of 160 mJ / cm ² . A plurality of latent images 36 corresponding to the plurality of openings 24 </ b> A and 24 </ b> B are formed on the resist film 30. This figure particularly shows the peripheral region of the isolated side.

As shown in FIG. 17, the mask pattern 22a is sequentially exposed at an exposure amount of 160 mJ / cm ² for each of the second exposure sections 18a to 18i of the second pattern section 4. A plurality of latent images 36a and 38 corresponding to the plurality of openings 24A and 24B are formed on the resist film 30. Here, the latent image 36 a is an image that is exposed by being superimposed on the latent image 36.

  As shown in FIG. 18, the resist film 30 is developed to form a drawn image 34 on the resist film 30. Here, since the latent image 38 is exposed with an exposure amount lower than the limit exposure amount Dm, it is not resolved even if it is developed. In this way, a resist pattern having a plurality of drawn images 34 arranged in 12000 rows and 12000 columns at a pitch of 500 nm is formed in the pattern region 12. The dimension of the drawn image 34 is measured by a scanning electron microscope (SEM) or the like, and it is confirmed that the desired dimension range of 350 nm ± 50 nm is satisfied.

  As shown in FIG. 19, the substrate 10 is selectively removed by dry etching or the like using the formed resist pattern as a mask. Thereafter, the resist pattern is removed, and an imprint mold having a plurality of concave transfer patterns 14 in the pattern region shown in FIG. 1 is manufactured.

  In the pattern forming method according to the embodiment, the first exposure sections 16a to 16d and the second exposure sections 18a to 18i are shifted in the row direction and the column direction at 3000 times the pitch. The peripheral regions where the defective drawing images 34a to 34d shown in FIGS. 10 and 11 are generated are several rows to several tens of rows and several tens of rows from the sides of the first and second exposure sections 16a to 16d and 18a to 18i. It is a range. In addition, the exposure amount of each of the first and second exposure sections 16a to 16d and 18a to 18i is 1/2 of the appropriate exposure amount and lower than the limit exposure amount. Therefore, the drawn image 34 can be formed in the pattern region 12 while suppressing the dimensional variation.

  In the above description, the first pattern section 2 is exposed first, but the order of exposure is not limited for all exposure sections. For example, the second pattern section 4 may be exposed first. Alternatively, the exposure sections 18a, 18b, 18c, 16b, 16a, 18d, 18e, 18f, 16d, 16c, 18g, 18h, and 18i may be sequentially exposed. In this case, the scanning time of the substrate stage and the mask stage for moving the substrate 10 and the exposure mask of the exposure apparatus can be shortened.

  In the above description, the pattern region 12 is double-exposed using the first and second pattern sections 2 and 4, but the pattern section may be three or more. For example, as shown in FIG. 20, a first pattern section 2 having a plurality of first exposure sections 16, a second pattern section 4 having a plurality of second exposure sections 18, and a first pattern section having a plurality of third exposure sections 19. Using the three pattern sections 6, the pattern area 12 corresponding to the first pattern section 2 may be subjected to triple exposure. Each of the exposure sections 16, 18, and 19 in the first to third pattern sections 2, 4, and 6 is an integral multiple of the pitch of a plurality of unit figures arranged in the mask pattern that exposes the exposure sections 16, 18, and 19 to each other. So that they are shifted from each other in the row and column directions. Each exposure section 16, 18, 19 is exposed with an exposure amount that is 1/3 of the appropriate exposure amount.

Here, the number of pattern sections to be used is N (N is an integer of 2 or more), the appropriate exposure amount is Do, the limit exposure amount is Dm, and the exposure amount of each exposure section is Di (i = 1 to N). . The relationship between the appropriate exposure dose Do and each exposure dose Di is

Do = D1 + D2 + ... + DN (1)

It is. Let D1 be the exposure amount for exposing the pattern section corresponding to the pattern region 12. The condition that the drawn image is not resolved in the area of the exposure section outside the pattern area 12 is as follows:

Dm> D2 + D3 + ... + DN (2)

It is. If exposure is attempted by changing the exposure amount of each exposure section, a setting change operation is added to the exposure apparatus, so that the time required for the exposure process increases. Therefore, it is desirable that Di be equal in all exposure sections.

Di = Do / N (3)

And set.

From equations (2) and (3)

N <1 / (1-Dm / Do) (4)

It can be expressed. Generally, since Dm / Do is about 0.6 to about 0.85, the number N of pattern sections satisfying the inequality (4) is 2 to 6. In order to improve the dimensional accuracy of the drawn image, the number N of pattern sections may be increased.

(Other embodiments)
Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment of the present invention, a drawn image of a resist film is formed using an optical reduction projection exposure apparatus. However, as the optical exposure apparatus, an equal magnification projection exposure apparatus or an enlarged projection exposure apparatus may be used. Further, a charged particle exposure apparatus using an electron beam or the like instead of the optical type may be used.

  Moreover, although the pattern formation method which concerns on embodiment is applied to the manufacturing method of the mold for imprint, it is not limited. You may apply to the manufacturing method of the electronic device by which a some unit figure is repeatedly arrange | positioned, or a printed circuit board.

  As described above, the present invention naturally includes various embodiments that are not described herein. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is the schematic which shows an example of the mold for imprint which concerns on embodiment of this invention. It is a plane schematic diagram showing an example of a pattern field of an imprint mold concerning an embodiment of the invention. It is the schematic which shows the AA cross section of the mold for imprint shown in FIG. It is a plane schematic diagram showing an example of an exposure mask used for explanation of an embodiment of the present invention. It is the schematic which shows the BB cross section of the exposure mask shown in FIG. It is a plane schematic diagram which shows the other example of the exposure mask used for description of embodiment of this invention. It is the schematic which shows an example of the division | segmentation of the pattern area | region which concerns on embodiment of this invention. 1 is a schematic plan view showing an example of a resist pattern according to an embodiment of the present invention. It is the schematic which shows CC cross section of the resist pattern shown in FIG. It is a plane schematic diagram showing an example of a defective drawing image used for explanation of an embodiment of the invention. It is a plane schematic diagram which shows the other example of the defect drawing image used for description of embodiment of this invention. It is the plane schematic which shows an example of arrangement | positioning of the 1st and 2nd exposure division which concerns on embodiment of this invention. It is a plane schematic diagram showing an example of arrangement of pattern division concerning an embodiment of the invention. It is a schematic plan view showing another example of the arrangement of the first and second exposure sections according to the embodiment of the present invention. It is sectional drawing (the 1) which shows an example of the manufacturing method of the imprint mold which concerns on embodiment of this invention. It is sectional drawing (the 2) which shows an example of the manufacturing method of the mold for imprint which concerns on embodiment of this invention. It is sectional drawing (the 3) which shows an example of the manufacturing method of the mold for imprint which concerns on embodiment of this invention. It is sectional drawing (the 4) which shows an example of the manufacturing method of the mold for imprint which concerns on embodiment of this invention. It is sectional drawing (the 5) which shows an example of the manufacturing method of the mold for imprint which concerns on embodiment of this invention. It is a plane schematic diagram which shows the other example of arrangement | positioning of the pattern division which concerns on embodiment of this invention.

Explanation of symbols

2 ... 1st pattern division 4 ... 2nd pattern division 10 ... Substrate 12 ... Pattern area 14 ... Transfer pattern 16, 16a-16d ... Exposure division, especially 1st exposure division 18, 18a-18i ... 2nd exposure division 20 ... Transparent Substrate 22, 22a ... Mask pattern 24, 24A, 24B ... Opening 26 ... Light shielding film 30 ... Resist film 34 ... Drawing image 34a-34d ... Defect drawing image 36, 36a, 38 ... Latent image

Claims (6)

Forming a resist film on the substrate;
Arranging a plurality of first exposure sections adjacent to each other in a pattern region defined on the substrate;
Sequentially exposing the resist pattern in each of the first exposure sections with a first exposure amount over the entire surface of the pattern region;
A plurality of second exposure sections having the same size as the first exposure section are arranged, and the second exposure section is set to the first exposure at an arbitrary integer multiple of a width corresponding to the pitch of the repeated figure included in the mask pattern. Setting so as to partially overlap each other by shifting in at least one of the row direction and the column direction with respect to the section;
Sequentially exposing the mask pattern to the resist film in each of the second exposure sections with a second exposure amount over a wider area than the pattern area;
Forming a drawn image on the resist film by development,
The sum of the first and second exposure amounts is an appropriate exposure amount at which the drawn image is formed with a desired dimension within the pattern region, and an insufficient exposure amount at which the drawn image is not formed outside the pattern region. A pattern forming method characterized by the above.   A width obtained by shifting the second exposure section with respect to the first exposure section by an arbitrary integer multiple of the width corresponding to the pitch is A, and the mask pattern is formed with the appropriate exposure amount in the plurality of first exposure sections. The width of the peripheral area of the one exposure section where a defective drawn image outside the desired dimension range is formed on the resist film when the resist film of one of the exposure sections is independently exposed and developed. The pattern forming method according to claim 1, wherein the relationship of A ≧ B is satisfied, where B is B. The mask pattern includes, as the unit graphic, a first graphic and a second graphic that shifts exposure light by π radians with respect to the first graphic,
The pattern forming method according to claim 1, wherein the first graphic and the second graphic are arranged adjacent to each other in the row and column directions. Forming a resist film on the substrate;
A plurality of first exposure sections are arranged adjacent to each other in a pattern area defined on the substrate, and a mask pattern is formed in the resist film of each of the first exposure sections with a first exposure amount over the entire pattern area. Are sequentially exposed to form a first pattern section, a plurality of second exposure sections having the same size as the first exposure section are arranged, and the width corresponding to the pitch of the repeated figure included in the mask pattern An area that is larger than the pattern area by arbitrarily multiplying the second exposure section with respect to the first exposure section by shifting to at least one of the row direction and the column direction at an arbitrary integer multiple Including sequentially exposing the mask pattern to the resist film in each of the second exposure sections at a second exposure amount to form a second pattern section. And Step N (N is an integer greater than or equal to 2) to create a number of pattern sections partially overlap each other,
Forming a drawn image on the resist film by development,
Each exposure section included in each of the N pattern sections is represented by Do /, where Dm is a limit exposure amount at which the drawn image is formed, and Do is an appropriate exposure quantity at which the drawn image is formed with a desired dimension. A pattern forming method, wherein exposure is successively performed with an exposure amount of N, and N satisfies a relationship of N <1 / (1-Dm / Do). Forming a resist film on the substrate;
Arranging a plurality of first exposure sections adjacent to each other in a pattern area defined on the substrate; a resist pattern for each of the first exposure sections with a first exposure amount over the entire pattern area; A plurality of second exposure sections having the same size as the first exposure section, and an arbitrary integral multiple of a width corresponding to a pitch of a repetitive figure included in the mask pattern. Setting two exposure sections so as to be partially overlapped with each other by shifting in at least one of a row direction and a column direction with respect to the first exposure section, at a second exposure amount over a wider area than the pattern area, A step of sequentially exposing a mask pattern to the resist film in each of the second exposure sections, and a development image is formed on the resist film by development Forming a resist pattern on the resist film in step,
Using the resist pattern as a mask, selectively removing the substrate,
The sum of the first and second exposure amounts is an appropriate exposure amount at which the drawn image is formed with a desired dimension within the pattern region, and an insufficient exposure amount at which the drawn image is not formed outside the pattern region. A method for producing an imprint mold, characterized by comprising: Forming a resist film on the substrate;
A plurality of first exposure sections are arranged adjacent to each other in a pattern area defined on the substrate, and a mask pattern is formed in the resist film of each of the first exposure sections with a first exposure amount over the entire pattern area. Are sequentially exposed to form a first pattern section, a plurality of second exposure sections having the same size as the first exposure section are arranged, and the width corresponding to the pitch of the repeated figure included in the mask pattern An area that is larger than the pattern area by arbitrarily multiplying the second exposure section with respect to the first exposure section by shifting to at least one of the row direction and the column direction at an arbitrary integer multiple Including sequentially exposing the mask pattern to the resist film in each of the second exposure sections at a second exposure amount to form a second pattern section. Creating a N (N is an integer not smaller than 2) patterns compartments that partially overlap each other, forming a resist pattern on the resist film by forming a graphic image on the resist film by development,
Selectively removing the substrate using the resist pattern as a mask,
Each exposure section included in each of the N pattern sections is represented by Do /, where Dm is a limit exposure amount at which the drawn image is formed, and Do is an appropriate exposure quantity at which the drawn image is formed with a desired dimension. A method for producing an imprint mold, wherein exposure is performed sequentially with an exposure amount of N, and N satisfies a relationship of N <1 / (1-Dm / Do).

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