JP2007048925A - Pattern forming method and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern forming method to easily form finer patterns, and also to provide a method of manufacturing semiconductor device using the same. <P>SOLUTION: A pattern 12a is formed by forming a first resist film 12A and a second resist film 12B on a substrate 10, exposing the second resist film 12B using a first photomask 20 having a first pattern 21, and then transferring the first pattern 21 to the second resist film 12B. Next, an aperture pattern 11 is formed through the first and second resist films 12B, 12A to a region 46, where the first pattern 21 and the second pattern 31 are overlapped by transferring the second pattern 31 to the first resist film 12A exposed by the second resist film 12B and the first pattern 21, in the manner that a part of the second pattern 31 is overlapped on the pattern 12a transferred to the second resist film 12B using the second photomask 30 including the second pattern 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pattern forming method and a semiconductor device manufacturing method, and more particularly to a pattern forming method for forming a miniaturized pattern and a semiconductor device manufacturing method using the same.

  In recent years, with the miniaturization of semiconductor devices, there has been a demand for miniaturization of patterns used in an exposure process when manufacturing the semiconductor device. In the technique for forming such a fine pattern, a high-resolution resist such as a chemically amplified photoresist made of an organic solvent containing an acid generator and a dissolution inhibitor has been used.

  However, in the conventional pattern formation method, since the pattern is formed by exposing the high resolution resist as described above once using a normal photomask, an opening having a size corresponding to the resolution of the exposure apparatus and the high resolution resist is formed. However, it could only be formed.

  As a method for solving such a problem, for example, there is a technique disclosed in Patent Document 1 shown below. In this prior art, the resist is exposed twice while shifting the position of the photomask, and then the resist is subjected to plasma ashing to form an opening pattern finer than the resolution limit. However, for example, when a positive resist is used, the position of the photomask is shifted so that a width finer than the resolution limit is double-exposed, and when a negative resist is used, for example, the resolution limit The position of the photomask is shifted so that a finer width is not exposed.

JP-A-7-147219

  However, in the above-described conventional technique, there is a risk that the side wall portion of the pattern formed in the first exposure may be exposed in the second exposure. For this reason, the width of the opening pattern formed by the second exposure may become wider than desired.

  Further, in the above-described conventional technique, it is necessary to perform plasma ashing after two exposures, so that the process becomes complicated and the semiconductor wafer needs to be moved from the exposure apparatus to the plasma ashing chamber. There was a problem that it took time and effort.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a pattern forming method capable of easily forming a finer pattern and a method of manufacturing a semiconductor device using the same. To do.

  In order to achieve such an object, a pattern forming method according to the present invention includes a step of preparing a predetermined substrate, a step of forming a first resist film on the predetermined substrate, and forming a second resist film on the first resist film. Using the first photomask having the first pattern to expose the second resist film, transferring the first pattern to the second resist film, and using the second photomask having the second pattern, By transferring the second pattern to the second resist film and the first resist film exposed by the first pattern so that a part of the second pattern overlaps the first pattern transferred to the second resist film. And a step of forming an opening pattern penetrating the first and second resist films in a region where the first pattern and the second pattern overlap.

  By transferring the second pattern so that a part of it overlaps with the first pattern transferred to the second resist film and the overlapping part opens, without depending on the dimensions of the first and second mask patterns. A fine pattern can be formed on a predetermined substrate. In other words, a pattern finer than the resolution limit can be formed. Further, in the present invention, first and second resist films are formed first, and this is sequentially exposed to form a pattern, so that a process such as plasma ashing or the time for transferring a predetermined substrate to another chamber is required. Etc. can be reduced. As a result, a finer pattern can be easily formed.

  The method for manufacturing a semiconductor device according to the present invention includes a step of preparing a semiconductor substrate on which a predetermined semiconductor element is formed, a step of forming a first resist film on the semiconductor substrate, and a second step on the first resist film. A step of forming a resist film, a step of transferring the first pattern to the second resist film by exposing the second resist film using a first photomask having the first pattern, and a second having the second pattern Using a photomask, the second pattern is formed on the second resist film and the first resist film exposed by the first pattern so that a part of the second pattern overlaps the first pattern transferred to the second resist film. A step of forming an opening pattern penetrating the first and second resist films in a region where the first pattern and the second pattern overlap by transferring.

  By transferring the second pattern so that a part of it overlaps with the first pattern transferred to the second resist film and the overlapping part opens, without depending on the dimensions of the first and second mask patterns. A fine pattern can be formed on a predetermined substrate. In other words, a pattern finer than the resolution limit can be formed. As a result, a finer semiconductor element can be formed. Further, in the present invention, first and second resist films are formed first, and this is sequentially exposed to form a pattern, so that a process such as plasma ashing or the time for transferring a predetermined substrate to another chamber is required. Etc. can be reduced. As a result, a finer pattern can be easily formed.

  According to the present invention, a pattern forming method and a semiconductor device manufacturing method capable of easily forming a finer pattern can be realized.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  First, Embodiment 1 according to the present invention will be described in detail with reference to the drawings. In this embodiment, two types of resists having different resolutions are used, and these are exposed twice using two types of photomasks having different pattern shapes, thereby forming a pattern finer than the resolution limit of the resist. In this embodiment, a case where a negative resist is used is taken as an example.

Shape of the photomasks 20 and 30 FIG. 1 shows a mask pattern (first mask pattern) 21 and a mask pattern (mask pattern) formed on the photomask (first photomask) 20 and photomask (second photomask) 30 used in this embodiment, respectively. The structure of the second mask pattern) 31 is shown. 1A is a top view of the mask pattern 21 formed on the photomask 20, and FIG. 1B is a top view of the mask pattern 31 formed on the photomask 30, and FIG. ) Is a diagram showing a region of each mask pattern (21, 31) used for overlapping exposure of a semiconductor substrate to be exposed (referred to as overlapping region 41). In this embodiment, a negative resist is used. Therefore, both mask patterns 21 and 31 shown in FIGS. 1A and 1B are regions through which laser light is transmitted. Further, the laser light that has passed through the overlapping regions 41 shown in FIG. 1C in each of the mask patterns 21 and 31 is irradiated to the same region in the semiconductor substrate to be exposed.

  In this embodiment, the photomask 20 is used for the first exposure, for example. For example, as shown in FIG. 1A, the photomask 20 has a rectangular region (hereinafter referred to as a tip) having a shorter width than one of the sides of a rectangular region (hereinafter referred to as a square portion 22). A convex mask pattern 21 to which a portion 23 is added). FIG. 1A shows an example in which a tip portion 23 is added to the right side of the square portion 22 for convenience of explanation. The square portion 22 may be, for example, a rectangle, a square, or another shape (including a triangle and other polygons). Moreover, when the square part 22 is made into a rectangle, for example, this square part 22 may be long arranged in the vertical direction or long in the horizontal direction in FIG. That is, in the mask pattern 21, the front end portion 23 may be added to the long side or the short side of the square portion 22.

  In the dimension of the square part 22, the length of the side to which the tip part 23 is added may be, for example, a dimension that has been conventionally used as a general mask pattern, or a dimension that is larger or smaller. Similarly, the length of the side other than the side to which the tip portion 23 is added may be, for example, a dimension that has been used as a conventional general mask pattern, or a dimension that is larger or smaller. In this example, the length of the side to which the tip portion 23 is added and the side facing the side is set to about 0.2 μm, for example, and the length of the other side is set to about 0.15 μm, for example.

  Further, the width of the tip portion 23 is a dimension that is lower than a dimension that has been generally used, and is a dimension capable of forming an opening pattern having a desired diameter on the semiconductor substrate. Moreover, it is preferable that the length of the front-end | tip part 23 shall be more than the dimension which can form the opening pattern of a desired diameter in a semiconductor substrate. For example, when an opening pattern having a diameter of about 0.1 μm is formed in a resist on a semiconductor substrate, the width of the tip 23 is about 0.1 μm, and the length of the tip 23 is, for example, about 0.15 μm (> 0.1 μm). And

  Such a mask pattern 21 is such that when the photomask 20 is installed in a predetermined exposure apparatus, the distal end portion 23 faces the distal end portion 33 (see FIG. 1B) of the photomask 30 that will be similarly installed in the later description, and the distal end. It arrange | positions so that the laser beam which permeate | transmitted the part 23 may be irradiated to the desired area | region (overlapping exposure area | region 46 (refer Fig.4 (a))) in a semiconductor substrate.

  The photomask 30 is used for the second exposure, for example. Similar to the photomask 20 shown in FIG. 1A, this photomask 30 has a rectangular area (hereinafter referred to as a rectangular area) having a width shorter than this side on any side of a rectangular area (hereinafter referred to as a square section 32). , Which is referred to as a tip portion 33) (see FIG. 1B). FIG. 1B shows an example in which a tip 33 is added to the left side of the square portion 32 for convenience of explanation. When the rectangular portion 32 is a rectangle, the rectangular portion 32 may be long in the vertical direction or long in the horizontal direction in FIG. That is, in the mask pattern 31, the tip end portion 33 may be added to the long side or the short side of the square portion 32.

  In the dimension of the square part 32, the length of the side to which the tip part 33 is added is the same as the square part 22, for example, a dimension that has been used as a conventional general mask pattern, or a dimension that is larger or smaller than that. It is good. Similarly, the length of the side other than the side to which the tip portion is added may be, for example, a dimension that has been used as a conventional general mask pattern, or may be longer or shorter. In this example, the length of the side to which the distal end portion 33 is added and the side facing the side are set to, for example, about 0.2 μm, similarly to the square portion 22, and the length of the other side is set to, for example, about 0.15 μm. And

  Similarly to the tip portion 23, the width of the tip portion 33 is also a size that is lower than a size that has been generally used, and is a size that can form an opening pattern having a desired diameter on the semiconductor substrate. . Further, the length of the tip portion 33 is preferably equal to or larger than the size capable of forming an opening pattern having a desired diameter on the semiconductor substrate, similarly to the tip portion 23. For example, when an opening pattern having a diameter of about 0.1 μm is formed in a resist on a semiconductor substrate, the width of the tip portion 33 is set to about 0.1 μm, for example, and the length of the tip portion 33 is set to about 0.15 μm, for example.

  As described above, when the photomask 30 is installed in a predetermined exposure apparatus, the mask pattern 31 faces the front end portion 23 (see FIG. 1A) of the photomask 20 installed in the above-described manner. In addition, the laser light transmitted through the distal end portion 33 is disposed so as to overlap and irradiate a desired region (overlapping exposure region 46 (see FIG. 7A)) in the semiconductor substrate to be exposed.

  Thus, in the mask pattern 21 and the mask pattern 31, as shown in FIG. 1C, when each photomask (20, 30) is irradiated with laser light in a state where it is installed in a predetermined exposure apparatus, It has a region (overlapping region 41) that irradiates the same region (overlapping exposure region 46). As described above, for example, when the opening pattern having a diameter of about 0.1 μm is formed, the overlapping region 41 has a size of about 0.1 μm as shown in FIG. Thus, by reducing the size of the overlapping region 41, it is possible to form a fine pattern. That is, the width of the tip portions 23 and 33, or the width of at least one of the tip portions 23/33 is set to a width that is as fine as required for the pattern to be formed, and the overlapping length is also required for the pattern to be formed. The desired fine pattern can be formed by setting the length to a very small length. Note that the term “fine” in the present embodiment means that it is finer than, for example, the dimensions in normal pattern formation and finer than the resolution limit of an exposure apparatus that performs exposure, for example.

In the photomasks 20 and 30 as described above, for example, a light shielding film using a chromium (Cr) film or the like is formed on a mask substrate such as synthetic quartz, and the mask pattern 21 or the mask pattern 21 or 30 is formed on the light shielding film as described above. For example, 31 can be manufactured by opening by etching. However, the present invention is not limited to this. For example, a chromium oxide film (CrO _x ), a molybdenum silicide (MoSi) oxide film, or a multilayer film including any one of a chromium oxide film and a molybdenum silicide oxide film is used. Even if a mask pattern equivalent to the mask pattern 21 or 31 is formed by using a halftone film and a light-shielding film using, for example, a chromium (Cr) film, the mask pattern 21 or 31 is equivalent to a Levenson equivalent thereto. It may be formed as a mold mask pattern.

  For example, when a 6-inch reticle generally used in KrF excimer laser lithography, i-line lithography or the like is used, the mask substrate thickness of the photomasks 20 and 30 can be set to 6.35 mm (millimeters), for example. However, the present invention is not limited to the above, and a substrate made of various materials and thicknesses can be used as a mask substrate.

Optical image formed using the photomasks 20 and 30 Next, an optical image formed on the resist when the resist on the predetermined semiconductor substrate is exposed using the photomasks 20 and 30 as described above. This will be described in detail with reference to the drawings. FIG. 2A shows an optical image 25 formed by the photomask 20 in the first exposure, and FIG. 2B shows a line II ′ of the optical image 25 shown in FIG. It is a graph which shows the relative light intensity along. FIG. 3A is a diagram showing an optical image 35 formed by the photomask 30 in the second exposure, and FIG. 3B is a line II-II of the optical image 35 shown in FIG. It is a graph which shows the relative light intensity along '. In this embodiment, the relative light intensity refers to a relative integrated value of the intensity of laser light irradiated to a certain region.

  In the present embodiment, the exposure time in the first exposure is a time necessary for removing a normal resist film (second resist film) 12B, which will be described later, and will be described later disposed below the normal resist film 12B. The time is such that the high-resolution resist film (first resist film) 12A is not completely removed, and preferably the removal (erosion) of the high-resolution resist 12A is negligible. Further, in this embodiment, the exposure time in the second exposure is a time necessary for removing the high resolution resist film 12A exposed by the transfer of the mask pattern 21, and is usually the resist film 12B and the high resolution resist. The time is such that the portion where the film 12A is laminated is not completely removed. That is, the resist film 12B and the high resolution resist film 12A are penetrated only in the region (overlap exposure region 41) where the mask pattern 31 is transferred so as to overlap the transferred mask pattern 21, in other words, the interlayer insulating film 11 is exposed. The time is sufficient to form the opening pattern 11a to be formed. In the present embodiment, as the high resolution resist, in addition to a commonly used high resolution resist, a material having a lower degree of corrosion with respect to a predetermined exposure condition than a resist film 12B described later can be applied.

  By setting the exposure time as described above in each exposure, it is possible to remove only the resist of the portion that is exposed in duplicate (see the overlapping exposure region 46 in FIG. 4A described later). That is, by forming the opening pattern 12c in the resist 12 (see FIGS. 7A and 7B) only in the overlapping exposure region 46, this portion of the semiconductor substrate (specifically, an interlayer insulating film 11 described later). Can only be exposed.

  Further, in this embodiment, for example, the film thickness of the normal resist film 12B described later and the film thickness of the high resolution resist film 12A are made the same, and the amount of laser light necessary for just removing the high resolution resist film 12A is used. However, assuming that the amount of the laser light necessary to remove the resist film 12B is about twice that of the normal resist film 12B, the relative light intensity of the optical image 35 is compared between FIG. 2 (b) and FIG. 3 (b). As is apparent, the relative light intensity of the optical image 25 by the first exposure is about twice. Therefore, in this embodiment, the exposure for removing the resist film 12B (corresponding to the first exposure) is called half exposure, and the exposure for removing the high resolution resist film 12A (corresponding to the second exposure). Is called full exposure.

  Further, FIG. 4A is a view showing a combined optical image 45 of the optical images 25 and 35 formed by the photomasks 20 and 30 in the first exposure and the second exposure, and FIG. It is a graph which shows the relative light intensity along line III-III 'of the synthetic optical image 45 shown to Fig.4 (a).

  As shown in FIGS. 2 to 4, in the optical image 25 and the optical image 35, a part of the region corresponding to the tip portions 23 and 33 of the mask patterns 21 and 31 respectively overlap. Accordingly, as shown in FIG. 4A, the combined optical image 45 obtained by combining these has a region that is exposed in an overlapping manner (overlapping exposure region 46). As shown in FIG. 4B, the overlapping exposure region 46 is a region having the highest relative light intensity. In the present embodiment, as described above, the resist (the high-resolution resist film 12A and the normal resist film 12B, which will be described later) having a film thickness that can be completely removed by the amount of laser light applied to the overlapping exposure region 46 is used. By forming on the semiconductor substrate that is the exposure target, the resist only in the overlapping exposure region 46 is completely removed.

-Manufacturing method of a semiconductor device Next, the manufacturing method of the semiconductor device 1 including the pattern formation method by a present Example is demonstrated in detail with drawing. In this manufacturing method, first, an element isolation insulating film (field insulating film) 13 formed to define the surface as an active region and a field region, and an active region surface of a semiconductor substrate (predetermined substrate) 10 are formed. A gate insulating film 14, a gate electrode 15 formed on the gate insulating film 14, and a pair of diffusion regions (source / drain) formed so as to sandwich the region below the gate electrode 15 in the active region. A semiconductor substrate 10 on which a transistor 17 having a region 16 is formed is prepared. The semiconductor substrate 10 may be, for example, a p-type silicon substrate, an n-type silicon substrate, or another semiconductor substrate. The transistor 17 may be p-type or n-type.

Next, for example, by using a CVD (Chemical Vapor Deposition) method, silicon oxide (SiO ₂ ), for example, is deposited on the surface of the semiconductor substrate 10 where the transistor 17 is formed, so that the transistor 10 is buried. An interlayer insulating film 11 made of an oxide film is formed. Next, the surface of the formed interlayer insulating film 11 is planarized using, for example, a CMP (Chemical and Mechanical Polishing) method. The planarized interlayer insulating film 11 is formed so as to have a thickness of, for example, about 5000 Å (angstrom) from the upper surface of the gate electrode 15 of the transistor 17.

  After that, as shown in FIG. 5A, a high resolution resist film 12A of about 2000 mm, for example, is formed on the interlayer insulating film 11 by spin-coating the above-described high resolution resist solution. As a material of the high resolution resist film 12A, for example, a chemically amplified photoresist made of an organic solvent containing an acid generator and a dissolution inhibitor can be used.

  Next, a high-resist resist film 12A formed as described above is spin-coated with a resist solution having a normal resolution, and as shown in FIG. Hereinafter, this is usually referred to as a resist film 12B. In addition, as a material of the resist film 12B, if it is a negative type photoresist, for example, a normal material such as a polymer material to which a bisazide compound is attached can be applied. However, the present invention is not limited to this, and any material that has a higher degree of corrosion with respect to predetermined exposure conditions than the above-described high-resolution resist film 12A can be used.

  As described above, by sequentially laminating the high-resolution resist film 12A and the normal resist film 12B, a structure in which two kinds of resists having different resolutions, which are peculiar to the present embodiment, are laminated. In FIG. 5B and subsequent drawings and in the following description, for simplification, the configuration of the element isolation insulating film 13 and the diffusion region 16 in the transistor 17 is omitted.

  Next, as shown in FIG. 6A, a photomask 20 shown in FIG. 1A is disposed above a predetermined distance from the surface on which the resist 12 is formed. Next, the normal resist film 12B on the semiconductor substrate 10 is exposed through the photomask 20, thereby removing the normal resist film 12B in the region where the optical image 25 as shown in FIG. 2A is formed. As a result, as shown in FIGS. 6A and 6B, the normal resist film 12B in the region corresponding to the optical image 25 is removed to form a resist pattern 12a, and the high resolution resist film 12A is exposed in this region. The FIG. 6B is a top view showing the configuration of the resist pattern 12a formed by the process shown in FIG.

  In the exposure step shown in FIG. 6A, for example, a laser beam having a wavelength of 248 nm (nanometer) can be used. As the laser light source, for example, an excimer laser KrF can be used. Further, as described above, the irradiation time under the exposure conditions is a time necessary for removing the normal resist film 12B, and the removal of the high resolution resist film 12A disposed under the normal resist film 12B can be ignored. For example, the time is about 140 ms. Furthermore, the depth of focus under the exposure conditions can be set to, for example, about 1.0 μm.

  Next, as shown in FIG. 7A, a photomask 30 shown in FIG. 1B is arranged at a predetermined distance above the surface on which the resist 12 is formed. Next, the normal resist film 12B and the exposed high-resolution resist film 12A are exposed through the photomask 30, so that the normal resist film in the region where the optical image 35 as shown in FIG. 12B and the high-resolution resist film 12A exposed in this region are removed. As a result, as shown in FIGS. 7A and 7B, the normal resist film 12B and the high-resolution resist film 12A are removed to form a resist pattern 12b, and an opening pattern 12c is formed in the overlapping exposure region 46. The As a result, the interlayer insulating film 11 is exposed in the overlapping exposure region 46. FIG. 7B is a top view showing the configuration of the resist pattern 12d formed by the process shown in FIG.

  Further, in the exposure step shown in FIG. 7A, for example, a laser beam having a wavelength of 248 nm can be used as in the exposure step shown in FIG. As the laser light source, for example, an excimer laser KrF can be used. Further, as described above, the exposure time under the exposure conditions is the time required to remove the high resolution resist film 12A, and the portion where the resist film 12B and the high resolution resist film 12A are normally laminated is completely removed. The time that is not removed is, for example, 300 ms. Furthermore, the depth of focus under the exposure conditions can be set to about 1.0 μm, for example.

  As described above, when the fine opening pattern 12c is provided in the resist 12 composed of the normal resist film 12B and the high resolution resist film 12A, as shown in FIG. 8A, the resist 12 is used as a mask from the opening pattern 12c. By etching the interlayer insulating film 11, an opening pattern 11 a is formed in the interlayer insulating film 11. As a result, the upper surface of the gate electrode 15 of the transistor 17 is exposed. Thereafter, as shown in FIGS. 8B and 8C, the normal resist film 12B and the high resolution resist film 12A on the interlayer insulating film 11 are removed. 8C shows the structure of the interlayer insulating film 11 in which the opening pattern 11a is formed and the normal resist film 12B and the high resolution resist film 12A are removed by the steps shown in FIGS. 8A and 8B. FIG.

  Thereafter, a conductor wiring such as tungsten (W) is filled in the opening pattern 11 a to form an in-contact wiring 18, and then a metal wiring layer 19 is formed on the interlayer insulating film 11 and the in-contact wiring 18. Thereby, the semiconductor device 1 as shown in FIG. 9 is formed.

As described above, in this embodiment, the predetermined substrate (11) is prepared, the first resist film (12A) is formed on the predetermined substrate (11), and the first resist film (12A) is formed on the first resist film (12A). The second resist film (12B) is formed, and the second resist film (12B) is exposed using the first photomask (20) having the first pattern (21), whereby the first pattern (21) is exposed to the second resist. A first pattern (a part of the second pattern (31) is transferred to the second resist film (12B) using a second photomask (30) having the second pattern (31) transferred to the film (12B). 21) by transferring the second pattern (31) onto the second resist film (12B) and the first resist film (12A) exposed by the first pattern (21) so as to overlap with the first pattern. (21) and second pattern (31) An opening pattern (11a) penetrating the first and second resist films (12B, 12A) is formed in a region (46) where and overlap.

  As described above, the second pattern (31) is transferred so that a part of the first pattern (21) is transferred onto the second resist film (12B) and the overlapping part (46) is opened. Thus, it is possible to form a fine pattern on the predetermined substrate without depending on the dimensions of the first and second patterns (21, 31). In other words, a pattern finer than the resolution limit can be formed. In the present invention, the first and second resist films (12A, 12B) are formed first, and this is sequentially exposed to form a pattern. It is possible to reduce the trouble of transferring to the chamber. As a result, a finer pattern can be easily formed.

  Furthermore, in this embodiment, the second pattern (31) is a third pattern (33) having a width finer than the resolution limit of the exposure apparatus for transferring the first and second patterns (21, 31). In addition, the second pattern (31) is transferred so that the third pattern (33) overlaps the first resist film (12A) exposed by the first pattern (21).

  Therefore, it is possible to form a pattern finer than the resolution limit without depending on the resolution limit of the exposure apparatus.

  Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the configuration not specifically mentioned is the same as that of the first embodiment. In this embodiment, a case where a negative resist is used is taken as an example.

FIG. 10 shows the configuration of mask patterns 21 ′ and 31 ′ formed on the photomasks 20 ′ and 30 ′ used in this embodiment. 10A is a top view of the mask pattern 21 ′ formed on the photomask 20 ′, and FIG. 10B is a top view of the mask pattern 31 ′ formed on the photomask 30 ′. FIG. 10 (c) is a diagram showing a region of each mask pattern (21 ′, 31 ′) used for overlapping exposure of a semiconductor substrate to be exposed (referred to as overlapping region 41 ′). In this embodiment, a negative resist is used. For this reason, both mask patterns 21 'and 31' shown in FIGS. 10A and 10B are regions through which laser light is transmitted. Further, the laser light that has passed through the overlapping regions 41 ′ shown in FIG. 10C in each of the mask patterns 21 ′ and 31 ′ is irradiated to the same region in the semiconductor substrate to be exposed.

  As shown in FIGS. 10A and 10B, the mask patterns 21 ′ and 31 ′ according to the present embodiment are the regions where the square portions 22 and 32 in the mask patterns 21 and 31 according to the first embodiment are circular ( Hereinafter, the tip portions 23 and 33 in the mask patterns 21 and 31 according to the first embodiment are respectively replaced with circular portions 22 ′ and 32 ′), and the tip portions 23 and 33 are arc-shaped regions (hereinafter, the tip portions 23 ′ and 33). Have the structure replaced by '). Other configurations are the same as those in the first embodiment. In this embodiment, the circular portions 22 ′ and 32 ′ are circular. However, the present invention is not limited to this, and various shapes such as an ellipse can be applied.

  The diameter of the circular portion 22 ′ may be, for example, a dimension that has been used as a conventional general mask pattern, or a dimension that is larger or smaller than that. In this example, the diameter of the circular portion 22 ′ is about 0.2 μm, for example. In addition, the size of the tip portion 23 ′ is the same as that of the tip portion 23 of the first embodiment. For example, when an opening pattern having a diameter of about 0.1 μm is formed in the resist in the semiconductor substrate, the width of the tip portion 23 ′ is set to 0. For example, the length of the tip 23 ′ is set to about 0.15 μm (> 0.1 μm).

  On the other hand, the diameter of the circular portion 32 ′ may be, for example, a dimension that has been conventionally used as a general mask pattern, or a dimension that is larger or smaller than that. In this example, the diameter of the circular portion 32 ′ is about 0.2 μm, for example. Similarly to the tip portion 23 ′, the tip portion 33 ′ has a dimension of, for example, a width of the tip portion 33 ′ of about 0.1 μm when an opening pattern having a diameter of about 0.1 μm is formed in the resist on the semiconductor substrate. The length of the tip 33 ′ is set to about 0.15 μm (> 0.1 μm), for example.

  In the above mask pattern 21 ′ and mask pattern 31 ′, as shown in FIG. 10C, when the respective photomasks (20 ′, 30 ′) are radiated with laser light in a state where they are installed in a predetermined exposure apparatus. In addition, there is a region (overlapping region 41 ′) that irradiates the same region (overlapping exposure region 46 ′). As described above, for example, when an opening pattern having a diameter of about 0.1 μm is formed, the overlapping region 41 ′ has a size of about 0.1 μm as shown in FIG. A fine pattern can be formed by keeping the dimensions finer than those in normal pattern formation. That is, the width of the tip portions 23 ′ and 33 ′ or the width of at least one tip portion 23 ′ / 33 ′ is set to a fine width as required for the pattern to be formed, and the length to be overlapped is also the pattern to be formed. By making the length as fine as required, a desired fine pattern can be formed.

Optical image formed using the photomasks 20 ′ and 30 ′ Next, when the resist on the predetermined semiconductor substrate is exposed twice using the photomasks 20 ′ and 30 ′ as described above, it is formed on the resist. The synthesized optical image formed will be described in detail with reference to the drawings. FIG. 11A shows a combined optical image 45 ′ of the optical images 25 ′ and 35 ′ formed by the photomasks 20 ′ and 30 ′ in the first exposure and the second exposure. FIG. 11B is a graph showing the relative light intensity along the line IV-IV ′ of the combined optical image 45 ′ shown in FIG.

  As shown in FIG. 11A, the optical image 25 'and the optical image 35' are partially overlapped with regions corresponding to the tip portions 23 'and 33' of the mask patterns 21 'and 31', respectively. Therefore, as shown in FIG. 11A, a combined optical image 45 'obtained by combining these has a region that is exposed in an overlapping manner (overlapping exposure region 46'). As shown in FIG. 11B, the overlapping exposure region 46 'is a region having the highest relative light intensity. In the present embodiment, as in the first embodiment, the resist (the high-resolution resist film 12A and the normal resist film 12B) having such a thickness that it can be completely removed by the amount of laser light applied to the overlapping exposure region 46 ′. Is formed on the semiconductor substrate to be exposed, so that the resist only in the overlapping exposure region 46 'is completely removed.

Semiconductor Device Manufacturing Method Further, the semiconductor device manufacturing method according to the present embodiment only replaces the photomasks 20 and 30 in the first embodiment with the photomasks 21 ′ and 30 ′ according to the present embodiment. Description is omitted.

As described above, in this embodiment, the predetermined substrate (11) is prepared, the first resist film (12A) is formed on the predetermined substrate (11), and the first resist film (12A) is formed on the first resist film (12A). Two resist films (12B) are formed, and the second resist film (12B) is exposed using a first photomask (20 ') having the first pattern (21'), whereby the first pattern (21 ') is exposed. Using the second photomask (30 ′) having the second pattern (31 ′) transferred to the second resist film (12B), a part of the second pattern (31 ′) is transferred to the second resist film (12B). The second pattern (31 ′) and the first resist film (12A) exposed by the first pattern (21 ′) are overlapped with the first pattern (21 ′) so as to overlap the first pattern (21 ′). By transferring to the first pattern (21 ') and the second pattern 31 to form an opening pattern penetrating the first and second resist film (12B, 12A) in ') and a region (46 which overlaps') (11a).

  In this way, the second pattern (31 ′) is transferred so that a part thereof overlaps the first pattern (21) transferred to the second resist film (12B) and the overlapping portion (46 ′) opens. By doing so, it is possible to form a fine pattern on a predetermined substrate without depending on the dimensions of the first and second patterns (21 ′, 31 ′). In other words, a pattern finer than the resolution limit can be formed. In the present invention, the first and second resist films (12A, 12B) are formed first, and this is sequentially exposed to form a pattern. It is possible to reduce the trouble of transferring to the chamber. As a result, a finer pattern can be easily formed.

  Furthermore, in the present embodiment, the second pattern (31 ′) is a third pattern (width) that is finer than the resolution limit of the exposure apparatus for transferring the first and second patterns (21 ′, 31 ′). 33 ′), and the second pattern (31 ′) is transferred such that the third pattern (33 ′) is superimposed on the first resist film (12A) exposed by the first pattern (21 ′).

  Therefore, it is possible to form a pattern finer than the resolution limit without depending on the resolution limit of the exposure apparatus.

  Next, Example 3 of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment or the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the configuration not specifically mentioned is the same as that of the first embodiment or the second embodiment. In this embodiment, a case where a negative resist is used is taken as an example.

Shape of Photomasks 20 ″ and 30 ″ FIG. 12 shows a configuration of mask patterns 21 ″ and 31 ″ formed on the photomasks 20 ″ and 30 ″ used in this embodiment, respectively. 12A is a top view of the mask pattern 21 ″ formed on the photomask 20 ″, and FIG. 12B is a top view of the mask pattern 31 ″ formed on the photomask 30 ″. FIG. 12C is a diagram showing a region (referred to as an overlapping region 41 ″) of each mask pattern (21 ″, 31 ″) used for overlapping exposure of a semiconductor substrate to be exposed. In this embodiment, a negative resist is used.Therefore, the mask patterns 21 "and 31" shown in FIGS. 12 (a) and 12 (b) are both regions through which laser light is transmitted. The laser beams that have passed through the overlapping regions 41 ″ shown in FIG. 12C in “and 31” are irradiated to the same region in the semiconductor substrate to be exposed.

  As shown in FIGS. 12A and 12B, the mask patterns 21 ″ and 31 ″ according to the present embodiment are configured only by a rectangular region. Other configurations are the same as those in the first embodiment.

  The mask patterns 21 ″ and 31 ″ are formed in a desired region (overlapping exposure) on the semiconductor substrate when the photomasks 20 ″ and 31 ″ are installed in a predetermined exposure apparatus, respectively, with the corners facing each other and the laser beams transmitted through the corners. It arrange | positions so that it may irradiate to area | region 46 "(refer Fig.13 (a)).

  Further, the dimensions of the sides of the mask patterns 21 ″ and 31 ″ may be, for example, dimensions conventionally used as a general mask pattern, or more or less. In this example, each of the mask patterns 21 ″ and 31 ″ is a square having a side of about 0.2 μm, for example.

  In the above mask pattern 21 ″ and mask pattern 31 ″, as shown in FIG. 12C, when the respective photomasks (20 ″, 30 ″) are placed in a predetermined exposure apparatus and irradiated with laser light. In addition, there is a region (overlapping region 41 ″) that irradiates the same region (overlapping exposure region 46 ″). This overlapping area 41 ″ is configured by overlapping the corners of the mask patterns 21 ″ and 31 ″. In other words, in this embodiment, the corners of the optical image 25 ″ by the mask pattern 21 ″ and the mask pattern 31 are formed. By adjusting the positions of the mask patterns 21 ″ and 31 ″ so that the corners of the optical image 35 ″ by “overlap” are overlapped to a desired extent, double exposure is performed on a minute region as desired.

Optical image formed using photomasks 20 ″ and 30 ″ Next, when a resist on a predetermined semiconductor substrate is exposed twice using the photomasks 20 ″ and 30 ″ as described above, it is formed on the resist. The synthesized optical image formed will be described in detail with reference to the drawings. FIG. 13A shows a combined optical image 45 ″ of the optical images 25 ″ and 35 ″ formed by the photomasks 20 ″ and 30 ″ in the first exposure and the second exposure. FIG. 13B is a graph showing the relative light intensity along the line VV ″ of the combined optical image 45 ″ shown in FIG.

  As shown in FIG. 13A, in the optical image 25 ″ and the optical image 35 ″, a part of the region corresponding to each corner of the mask patterns 21 ″ and 31 ″ is overlapped. Therefore, as shown in FIG. 13A, the combined optical image 45 ″ obtained by combining these has a region that is exposed in an overlapping manner (overlapping exposure region 46 ″). As shown in FIG. 13B, the overlapping exposure region 46 ″ is a region having the strongest relative light intensity. In this embodiment, similarly to the first embodiment, the laser irradiated to the overlapping exposure region 46 ″. By forming a resist (a high-resolution resist film 12A and a normal resist film 12B) having a thickness that can be completely removed by the amount of light on the semiconductor substrate to be exposed, only this overlapping exposure region 46 " The resist is completely removed.

Semiconductor Device Manufacturing Method Further, the semiconductor device manufacturing method according to the present embodiment only replaces the photomasks 20 and 30 in the first embodiment with the photomasks 21 ″ and 30 ″ according to the present embodiment. Description is omitted.

As described above, in this embodiment, the predetermined substrate (11) is prepared, the first resist film (12A) is formed on the predetermined substrate (11), and the first resist film (12A) is formed on the first resist film (12A). The second resist film (12B) is formed, and the second resist film (12B) is exposed using the first photomask (20 ") having the first pattern (21") to thereby form the first pattern (21 "). Using the second photomask (30 ″) having the second pattern (31 ″) transferred to the second resist film (12B), a part of the second pattern (31 ″) is transferred to the second resist film (12B). The second pattern (31 ″) and the first resist film (12A) exposed by the first pattern (21 ″) are overlapped with the first pattern (21 ″). To the first pattern (21 ″) An opening pattern (11a) penetrating the first and second resist films (12B, 12A) is formed in a region (46 ″) where the second pattern (31 ″) overlaps.

  As described above, the second pattern (31 ″) is transferred so that a part of the first pattern (21) is transferred onto the second resist film (12B) and the overlapping portion (46 ″) is opened. Thus, it is possible to form a fine pattern on a predetermined substrate without depending on the dimensions of the first and second patterns (21 ″, 31 ″). In other words, a pattern finer than the resolution limit can be formed. In the present invention, the first and second resist films (12A, 12B) are formed first, and this is sequentially exposed to form a pattern. It is possible to reduce the trouble of transferring to the chamber. As a result, a finer pattern can be easily formed.

  Furthermore, in this embodiment, the first pattern (21 ″) has a first corner, the second pattern (31 ″) has a second corner, and the second pattern (31 ″) has a second corner. The corner is transferred so as to overlap the first corner of the first pattern (21 ″) transferred to the second resist film (12B).

  Therefore, it is possible to form a pattern finer than the resolution limit without depending on the resolution limit of the exposure apparatus.

  Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the configuration not specifically mentioned is the same as any one of the first to third embodiments. In this embodiment, a case where a negative resist is used is taken as an example.

FIG. 14 shows the structures of mask patterns 21 ″ ′ and 31 ″ ′ formed on the photomasks 20 ″ ′ and 30 ″ ′ used in this embodiment, respectively. 14A is a top view of the mask pattern 21 ″ ′ formed on the photomask 20 ″ ′, and FIG. 14B is a top view of the mask pattern 31 ″ ′ formed on the photomask 30 ″ ′. FIG. 14C shows an area (referred to as an overlapping area 41 ″ ′) of each mask pattern (21 ″ ′, 31 ″ ′) used for overlapping exposure of the semiconductor substrate to be exposed. In this embodiment, a negative resist is used, so that the mask patterns 21 "'and 31"' shown in FIGS. Further, the laser light that has passed through the overlapping regions 41 ″ ′ shown in FIG. 14C in the mask patterns 21 ″ ′ and 31 ″ ′ is irradiated to the same region in the semiconductor substrate to be exposed.

  As shown in FIGS. 14A and 14B, the mask patterns 21 "" and 31 "" according to the present embodiment are composed of only rectangular regions. However, the extending direction of the long side of the rectangle is different between the mask pattern 21 "" and the mask pattern 31 "". For example, in the example shown in FIGS. 14A and 14B, the extending direction of the long side of the mask pattern 21 ″ ″ and the extending direction of the long side of the mask pattern 31 ″ ″ are orthogonal to 90 °. Other configurations are the same as those in the first embodiment.

  The mask patterns 21 "'and 31"' are desired in the semiconductor substrate when the photomasks 20 "'and 31"' are respectively installed in a predetermined exposure apparatus, and the laser beams that intersect with each other at the middle part and transmitted through the intersecting regions are desired. It arrange | positions so that an area | region (overlapping exposure area | region 46 '' '(refer Fig.15 (a)) may be irradiated.

  Further, the long side dimension of the mask patterns 21 "" and 31 "" may be, for example, a dimension conventionally used as a general mask pattern, or a dimension larger or smaller than that. In this example, the length of each long side is, for example, about 0.3 μm. Further, the dimension of the short sides of the mask patterns 21 "" and 31 "" is, for example, about 0.1 [mu] m when an opening pattern having a diameter of about 0.1 [mu] m is formed in the resist on the semiconductor substrate.

  In the above mask pattern 21 ″ ′ and mask pattern 31 ″ ′, as shown in FIG. 14C, the laser beam is set in a state where the respective photomasks (20 ″ ′, 30 ″ ′) are installed in a predetermined exposure apparatus. , The same region (overlapping exposure region 46 "') is irradiated (overlapping region 41"'). The overlapping region 41 ″ ′ is configured by overlapping the mask patterns 21 ″ ′ and 31 ″ ′. That is, in this embodiment, the optical image 25 ″ ′ by the mask pattern 21 ″ ′ and the mask pattern 31 ″ ′. By superimposing the optical image 35 "'by the above, a fine area corresponding to the width of the mask patterns 21"' and 31 "'is double-exposed.

Optical image formed using photomasks 20 "'and 30"' Next, when a resist on a predetermined semiconductor substrate is exposed twice using the photomasks 20 "'and 30"' as described above A composite optical image formed on the resist will be described in detail with reference to the drawings. FIG. 15A shows a combined optical image 45 ″ ′ of the optical images 25 ″ ′ and 35 ″ ′ formed by the photomasks 20 ″ ′ and 30 ″ ′ in the first exposure and the second exposure. FIG. 15B is a graph showing the relative light intensity along the line VI-VI ″ ′ of the combined optical image 45 ″ ′ shown in FIG.

  As shown in FIG. 15 (a), the optical image 25 "" and the optical image 35 "" overlap with regions corresponding to the middle portions of the mask patterns 21 "" and 31 "". Therefore, as shown in FIG. 15A, the combined optical image 45 "" obtained by synthesizing these has a region that is exposed in an overlapping manner (overlapping exposure region 46 "'). As shown in FIG. 15B, the overlapping exposure region 46 ″ ′ is a region having the strongest relative light intensity. In this embodiment, the overlapping exposure region 46 ″ ′ is irradiated as in the first embodiment. By forming a resist (a high-resolution resist film 12A and a normal resist film 12B) having a thickness that can be completely removed by the amount of laser light to be exposed on the semiconductor substrate to be exposed, this overlapping exposure region 46 It is configured so that only the resist "" is completely removed.

Semiconductor Device Manufacturing Method Also, the semiconductor device manufacturing method according to the present embodiment only replaces the photomasks 20 and 30 in the first embodiment with the photomasks 21 ″ ′ and 30 ″ ′ according to the present embodiment. Detailed description is omitted.

As described above, in this embodiment, the predetermined substrate (11) is prepared, the first resist film (12A) is formed on the predetermined substrate (11), and the first resist film (12A) is formed on the first resist film (12A). The second resist film (12B) is formed, and the second resist film (12B) is exposed using the first photomask (20 ″ ′) having the first pattern (21 ″ ′), whereby the first pattern (21 ″) is exposed. ′) Is transferred to the second resist film (12B), and a second photomask (30 ″ ′) having the second pattern (31 ″ ′) is used, and a part of the second pattern (31 ″ ′) is the second resist. The second pattern (31 ″ ′) is exposed by the second resist film (12B) and the first pattern (21 ″ ′) so as to overlap the first pattern (21 ″ ′) transferred to the film (12B). By transferring to the first resist film (12A), the first pattern (21 An opening pattern (11a) penetrating the first and second resist films (12B, 12A) is formed in a region (46 "') where"") and the second pattern (31"') overlap.

  Thus, the second pattern (31 ″ ′) is partially overlapped with the first pattern (21) transferred to the second resist film (12B), and the overlapping portion (46 ″ ′) is opened. By transferring the pattern, it becomes possible to form a fine pattern on a predetermined substrate without depending on the dimensions of the first and second patterns (21 ″ ′, 31 ″ ′). In other words, a pattern finer than the resolution limit can be formed. In the present invention, the first and second resist films (12A, 12B) are formed first, and this is sequentially exposed to form a pattern. It is possible to reduce the trouble of transferring to the chamber. As a result, a finer pattern can be easily formed.

  Further, in the present embodiment, the resolution limit of the exposure apparatus for transferring the first and second patterns (21 ″ ′, 31 ″ ′) to the first and second patterns (21 ″ ′, 31 ″ ′). The second pattern (31 ″ ′) is a rectangle having a finer shorter side, and the second pattern (31 ″ ′) is transferred to the second resist film (12B) by the first pattern (21B). It is transcribed so that it intersects the long side of "').

  Therefore, it is possible to form a pattern finer than the resolution limit without depending on the resolution limit of the exposure apparatus.

  Next, a fifth embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the configuration not specifically mentioned is the same as that of any one of the first to fourth embodiments. In this embodiment, a case where a negative resist is used is taken as an example.

Shape of Photomasks 20 "" and 30 "" FIG. 16 shows the structures of mask patterns 21 "" and 31 "" respectively formed on the photomasks 20 "" and 30 "" used in this embodiment. 16A is a top view of the mask pattern 21 ″ ″ formed on the photomask 20 ″ ″, and FIG. 16B is a top view of the mask pattern 31 ″ ″ formed on the photomask 30 ″ ″. FIG. 16C shows an area (referred to as an overlapping area 41 ″ ″) of each mask pattern (21 ″ ″, 31 ″ ″) used for overlapping exposure of a semiconductor substrate to be exposed. FIG. In this embodiment, a negative resist is used. For this reason, both mask patterns 21 "" and 31 "" shown in FIGS. 16A and 16B are regions through which laser light is transmitted. Further, the laser light that has passed through the overlapping regions 41 ″ ″ shown in FIG. 16C in each of the mask patterns 21 ″ ″ and 31 ″ ″ is irradiated to the same region in the semiconductor substrate to be exposed.

  As shown in FIGS. 16A and 16B, the mask patterns 21 "" and 31 "" according to the present embodiment are so-called line-and-space patterns in which line-shaped openings are arranged at predetermined intervals. It consists of However, the direction in which the line-shaped opening extends is different between the mask pattern 21 "" and the mask pattern 31 "". For example, in the example shown in FIGS. 16A and 16B, the extending direction of the line-shaped opening in the mask pattern 21 ″ ″ and the extending direction of the line-shaped opening in the mask pattern 31 ″ ″ are 90 °. Orthogonal to Other configurations are the same as those in the first embodiment.

  The mask patterns 21 "" and 31 "" are formed in a desired region (overlapping) of the laser beam that intersects each other and transmits through the intersecting region when the photomasks 20 "" and 31 "" are installed in a predetermined exposure apparatus. It arrange | positions so that exposure area | region 46 "" (refer Fig.17 (a)) may be irradiated.

  The widths of the mask patterns 21 ″ ″ and 31 ″ ″ are, for example, about 0.1 μm when an opening pattern having a diameter of about 0.1 μm is formed in a resist on a semiconductor substrate.

  In the above mask pattern 21 ″ ″ and mask pattern 31 ″ ″, as shown in FIG. 16C, the laser beam with the respective photomasks (20 ″ ″, 30 ″ ″) installed in a predetermined exposure apparatus. , The same region (overlapping exposure region 46 "") is irradiated (overlapping region 41 ""). The overlapping area 41 "" is configured by overlapping the mask patterns 21 "" and 31 "". In other words, in the present embodiment, the optical image 25 ″ ″ by the mask pattern 21 ″ ″ and the optical image 35 ″ ″ by the mask pattern 31 ″ ″ are overlapped to correspond to the width of the mask patterns 21 ″ ″ and 31 ″ ″. Double exposure is performed on a region as fine as possible.

Optical image formed using photomasks 20 "" and 30 "" Next, when a resist on a predetermined semiconductor substrate is exposed twice using the photomasks 20 "" and 30 "" as described above. A composite optical image formed on the resist will be described in detail with reference to the drawings. FIG. 17A is a view showing a combined optical image 45 ″ ″ of optical images 25 ″ ″ and 35 ″ ″ formed by the photomasks 20 ″ ″ and 30 ″ ″ in the first exposure and the second exposure. FIG. 17B is a graph showing the relative light intensity along the line VII-VII ″ ″ of the combined optical image 45 ″ ″ shown in FIG.

  As shown in FIG. 17A, the optical image 25 ″ ″ and the optical image 35 ″ ″ have a predetermined interval according to the arrangement of the line-shaped openings constituting the mask patterns 21 ″ ″ and 31 ″ ″. Superimpose with. Accordingly, as shown in FIG. 17A, the combined optical image 45 ″ ″ obtained by combining these has a plurality of regions that are exposed in an overlapping manner (overlapping exposure regions 46 ″ ″). This overlapping exposure region 46 ″ ″ is a region having the strongest relative light intensity, as shown in FIG. In the present embodiment, as in the first embodiment, the resist (the high-resolution resist film 12A and the normal resist film 12B) having a film thickness that can be completely removed by the amount of laser light applied to the overlapping exposure region 46 ″ ″. ) Is formed on the semiconductor substrate to be exposed, so that the resist only in the overlapping exposure region 46 "" is completely removed.

Semiconductor Device Manufacturing Method Further, the semiconductor device manufacturing method according to the present embodiment only replaces the photomasks 20 and 30 in the first embodiment with the photomasks 21 ″ ″ and 30 ″ ″ according to the present embodiment. Detailed description is omitted.

As described above, in this embodiment, the predetermined substrate (11) is prepared, the first resist film (12A) is formed on the predetermined substrate (11), and the first resist film (12A) is formed on the first resist film (12A). The second resist film (12B) is formed, and the second resist film (12B) is exposed using the first photomask (20 "") having the first pattern (21 ""), whereby the first pattern (21 "") Is transferred to the second resist film (12B), and the second photomask (30"") having the second pattern (31"") is used. The second pattern (31 ″ ″) is exposed by the second resist film (12B) and the first pattern (21 ″ ″) so as to overlap the first pattern (21 ″ ″) transferred to the film (12B). The first resist film (12A) is transferred to the first resist film. An opening pattern (11a) penetrating the first and second resist films (12B, 12A) is formed in a region (46 "") where the turn (21 "") and the second pattern (31 "") overlap.

  As described above, the second pattern (31 ″ ″) is partially overlapped with the first pattern (21) transferred to the second resist film (12B), and the overlapping portion (46 ″ ″) is opened. By transferring the pattern, it becomes possible to form a fine pattern on a predetermined substrate without depending on the dimensions of the first and second patterns (21 ″ ″, 31 ″ ″). In other words, a pattern finer than the resolution limit can be formed. In the present invention, the first and second resist films (12A, 12B) are formed first, and this is sequentially exposed to form a pattern. It is possible to reduce the trouble of transferring to the chamber. As a result, a finer pattern can be easily formed.

  Furthermore, in this embodiment, the resolution limit of the exposure apparatus for transferring the first and second patterns (21 ″ ″, 31 ″ ″) to the first and second patterns (21 ″ ″, 31 ″ ″). The line-and-space pattern is a line having a finer width, and the second pattern (31 ″ ″) intersects the first pattern (21 ″ ″) transferred to the second resist film (12B). Transcribed.

  Therefore, it is possible to form a pattern finer than the resolution limit without depending on the resolution limit of the exposure apparatus.

  In addition, the first to fifth embodiments described above are merely examples for carrying out the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention. It is obvious from the above description that various other embodiments are possible within the scope of the present invention.

  In each of the above-described embodiments, the negative resist is applied to the high resolution resist film 12A and the normal resist film 12B. However, the present invention is not limited to this, and for example, a positive resist can be used. is there. However, in this case, the mask pattern in each of the above embodiments is inverted.

(A) is a top view of the mask pattern 21 formed on the photomask 20 according to the first embodiment of the present invention, and (b) is a top view of the mask pattern 31 formed on the photomask 30 according to the first embodiment of the present invention. (C) is a diagram showing an overlapping region 41 of each mask pattern (21, 31) used for overlapping exposure of a semiconductor substrate to be exposed in Example 1 of the present invention. (A) is a figure which shows the optical image 25 imaged with the photomask 20 in the 1st exposure in Example 1 of this invention, (b) is line | wire II 'of the optical image 25 shown to (a). It is a graph which shows the relative light intensity along. (A) is a figure which shows the optical image 35 imaged with the photomask 30 in the 2nd exposure in Example 1 of this invention, (b) is line II-II 'of the optical image 35 shown to (a). It is a graph which shows the relative light intensity along. (A) is a figure which shows the synthetic | combination optical image 45 of the optical images 25 and 35 imaged by the photomasks 20 and 30 in the 1st exposure and the 2nd exposure in Example 1 of this invention, (b) These are the graphs which show the relative light intensity along line III-III 'of the synthetic optical image 45 shown to (a). It is a process figure which shows the manufacturing method of the semiconductor device 1 using the pattern formation method by Example 1 of this invention (1). It is process drawing which shows the manufacturing method of the semiconductor device 1 using the pattern formation method by Example 1 of this invention (2). It is a process figure which shows the manufacturing method of the semiconductor device 1 using the pattern formation method by Example 1 of this invention (3). It is a process figure which shows the manufacturing method of the semiconductor device 1 using the pattern formation method by Example 1 of this invention (4). It is a process figure which shows the manufacturing method of the semiconductor device 1 using the pattern formation method by Example 1 of this invention (5). (A) is a top view of the mask pattern 21 'formed on the photomask 20' according to the second embodiment of the present invention, and (b) is a mask pattern 31 formed on the photomask 30 'according to the second embodiment of the present invention. (C) shows an overlapping region 41 ′ of each mask pattern (21 ′, 31 ′) used for overlapping exposure of the semiconductor substrate to be exposed in Example 2 of the present invention. FIG. (A) It is a figure which shows the synthetic | combination optical image 45 'of optical image 25' and 35 'imaged by photomask 20' and 30 'in the 1st exposure and the 2nd exposure in Example 2 of this invention. (B) is a graph which shows the relative light intensity along line IV-IV 'of the synthetic optical image 45' shown to (a). (A) is a top view of the mask pattern 21 ″ formed on the photomask 20 ″ according to the third embodiment of the present invention, and (b) is a mask pattern 31 formed on the photomask 30 ″ according to the third embodiment of the present invention. "(C) shows an overlapping region 41" of each mask pattern (21 ", 31") used for overlapping exposure of the semiconductor substrate to be exposed in Example 3 of the present invention. FIG. (A) It is a figure which shows the synthetic | combination optical image 45 "of the optical images 25" and 35 "imaged by the photomasks 20" and 30 "in the 1st exposure and the 2nd exposure in Example 3 of this invention. (B) is a graph which shows the relative light intensity along line VV 'of the synthetic optical image 45' 'shown to (a). (A) is a top view of the mask pattern 21 ″ ′ formed on the photomask 20 ″ ′ according to the fourth embodiment of the present invention, and (b) is formed on the photomask 30 ″ ″ according to the fourth embodiment of the present invention. FIG. 10C is a top view of the mask pattern 31 ″ ′, and FIG. 10C shows each mask pattern (21 ″ ′, 31 ″ ′) used for overlapping exposure of the semiconductor substrate to be exposed in Example 4 of the present invention. It is a figure which shows the overlap area | region 41 '' '. (A) The combined optical image 45 ″ ′ of the optical images 25 ″ ′ and 35 ″ ′ formed by the photomasks 20 ″ ′ and 30 ″ ′ in the first exposure and the second exposure in Embodiment 4 of the present invention. (B) is a graph showing the relative light intensity along the line VI-VI ′ of the synthesized optical image 45 ″ ′ shown in (a). (A) is a top view of the mask pattern 21 "" formed on the photomask 20 "" according to the fifth embodiment of the present invention, and (b) is formed on the photomask 30 "" according to the fifth embodiment of the present invention. FIG. 10C is a top view of the mask pattern 31 ″ ″, and FIG. 10C shows each mask pattern (21 ″ ″, 31 ″ ″) used for overlapping exposure of the semiconductor substrate to be exposed in the fifth embodiment of the present invention. FIG. (A) A combined optical image 45 ″ ″ of optical images 25 ″ ″ and 35 ″ ″ formed by the photomasks 20 ″ ″ and 30 ″ ″ in the first exposure and the second exposure in the fifth embodiment of the present invention. (B) is a graph showing the relative light intensity along the line VI-VI ′ of the synthesized optical image 45 ″ ″ shown in (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 10 Semiconductor substrate 11 Interlayer insulating film 11a Opening pattern 12 Resist 12A High resolution resist film 12B Normal resist film 12a, 12b, 12d Resist pattern 12c Opening pattern 13 Element isolation insulating film 14 Gate insulating film 15 Gate electrode 16 Diffusion region 17 Transistor 18 Contact wiring 19 Metal wiring layer 20, 20 ', 20 ", 20"', 20 "", 30, 30 ', 30 ", 30"', 30 "" Photomask 21, 21 ', 21 ", 21 "', 21"", 31, 31', 31", 31 "', 31""Mask pattern 22, 32 Square portion 22', 32 'Circular portion 23, 23', 33, 33 'Tip portion 25, 25 ', 25 ", 25"', 25 "", 35, 35 ', 35 ", 35"', 35 "" Optical image 41, 41 ', 41 ", 41"', 4 "" Overlapping region 45, 45 ', 45 ", 45"', 45 "" Synthesis optical images 46,46 ', 46 ", 46"', 46 "" overlapped exposure region

Claims (16)

Preparing a predetermined substrate;
Forming a first resist film on the predetermined substrate;
Forming a second resist film on the first resist film;
Transferring the first pattern to the second resist film by exposing the second resist film using a first photomask having a first pattern;
A second photomask having a second pattern is used, and the second pattern is overlapped with the second resist film so that a part of the second pattern overlaps the first pattern transferred to the second resist film. By transferring to the first resist film exposed by the first pattern, an opening pattern penetrating the first and second resist films is formed in a region where the first pattern and the second pattern overlap. A pattern forming method comprising the steps of: The first pattern is transferred under exposure conditions that expose the first resist film,
The second pattern completely removes the first resist film exposed in a region overlapping with the first pattern, and completely removes the first resist film in a region where the first pattern is not formed. 2. The pattern forming method according to claim 1, wherein the pattern is transferred under exposure conditions that do not.   The pattern forming method according to claim 1, wherein the second resist film has a higher degree of corrosion with respect to a predetermined exposure condition than the first resist film.   The pattern forming method according to claim 1, wherein the first resist film is a chemically amplified photoresist. The second pattern includes a third pattern having a width finer than a resolution limit of an exposure apparatus for transferring the first and second patterns,
5. The second pattern according to claim 1, wherein the second pattern is transferred so that the third pattern overlaps the first resist film exposed by the first pattern. 6. Pattern forming method. The first pattern has a first corner,
The second pattern has a second corner,
The said 2nd pattern is transcribe | transferred so that the said 2nd corner | angular part may overlap with the said 1st corner | angular part of the said 1st pattern transcribe | transferred to the said 2nd resist film. The pattern formation method of any one of Claims 1. The first and second patterns are rectangles having short sides finer than the resolution limit of an exposure apparatus for transferring the first and second patterns,
The said 2nd pattern is transcribe | transferred so that the long side of the said 2nd pattern may cross | intersect the long side of the said 1st pattern transcribe | transferred to the said 2nd resist film. 2. The pattern forming method according to item 1. The first and second patterns are line and space patterns composed of lines having a width smaller than a resolution limit of an exposure apparatus for transferring the first and second patterns,
5. The pattern forming method according to claim 1, wherein the second pattern is transferred so as to intersect the first pattern transferred to the second resist film. 6. Preparing a semiconductor substrate on which a predetermined semiconductor element is formed;
Forming a first resist film on the semiconductor substrate;
Forming a second resist film on the first resist film;
Transferring the first pattern to the second resist film by exposing the second resist film using a first photomask having a first pattern;
A second photomask having a second pattern is used, and the second pattern is overlapped with the second resist film so that a part of the second pattern overlaps the first pattern transferred to the second resist film. By transferring to the first resist film exposed by the first pattern, an opening pattern penetrating the first and second resist films is formed in a region where the first pattern and the second pattern overlap. A method for manufacturing a semiconductor device, comprising the steps of: The first pattern is transferred under exposure conditions that expose the first resist film,
The second pattern completely removes the first resist film exposed in a region overlapping with the first pattern, and completely removes the first resist film in a region where the first pattern is not formed. 10. The method of manufacturing a semiconductor device according to claim 9, wherein the transfer is performed under exposure conditions that do not.   11. The method of manufacturing a semiconductor device according to claim 9, wherein the second resist film has a higher degree of corrosion with respect to a predetermined exposure condition than the first resist film.   The method of manufacturing a semiconductor device according to claim 9, wherein the first resist film is a chemically amplified photoresist. The second pattern includes a third pattern having a width finer than a resolution limit of an exposure apparatus for transferring the first and second patterns,
The said 2nd pattern is transcribe | transferred so that the said 3rd pattern may overlap with the said 1st resist film exposed by the said 1st pattern, The any one of Claim 9 to 12 characterized by the above-mentioned. A method for manufacturing a semiconductor device. The first pattern has a first corner,
The second pattern has a second corner,
13. The second pattern according to claim 9, wherein the second pattern is transferred so that the second corner is superimposed on the first corner of the first pattern transferred to the second resist film. A manufacturing method of a semiconductor device given in any 1 paragraph. The first and second patterns are rectangles having short sides finer than the resolution limit of an exposure apparatus for transferring the first and second patterns,
The second pattern is transferred so that the long side of the second pattern intersects the long side of the first pattern transferred to the second resist film. 2. A method for manufacturing a semiconductor device according to item 1. The first and second patterns are line and space patterns composed of lines having a width smaller than a resolution limit of an exposure apparatus for transferring the first and second patterns,
13. The method of manufacturing a semiconductor device according to claim 9, wherein the second pattern is transferred so as to cross the first pattern transferred to the second resist film.

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