JP2016028442A - Template - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a template for imprint for transferring an uneven pattern to a photocurable material, the template having a high-contrast alignment mark having high resistance to washing.SOLUTION: A template is used for imprint for pressing a template having an uneven pattern on one principal surface of a light transmissible base material against a photocurable material on a processing target substrate, and exposing the photocurable material to light through the template to photocure the photocurable material, thereby transferring the uneven pattern. A light shielding film pattern serving as an alignment mark is provided on protrusion portions of the uneven pattern of the template, and the upper surface and side surface of the light shielding film pattern are covered with a protection film having resistance to washing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a template used in an imprint method for forming a fine uneven pattern.

  In recent years, particularly in semiconductor devices, high speed operation and low power consumption operation are required due to further progress in miniaturization, and high technology such as integration of functions called system LSIs is required. Under such circumstances, the lithography technology that is necessary for producing the pattern of the semiconductor device has become very expensive as the exposure apparatus and the like as the pattern becomes finer, and the price of the mask used therefor also becomes expensive. Yes.

  On the other hand, the imprint method proposed by Chou et al. In Princeton University in 1995 is attracting attention as a fine pattern forming technique having a high resolution of about 10 nm, although the apparatus price and the materials used are low ( Patent Document 1).

  In the imprint method, a template (also referred to as a mold, stamper, or mold) in which a nanometer-sized concavo-convex pattern has been formed on the surface in advance is pressed against a resin (also referred to as a resist in the present invention) applied to the surface of the substrate to be processed In this technique, a fine pattern is precisely transferred by mechanically deforming, and a substrate to be processed is processed using the patterned resin as a resist mask. Once the template is made, the nanostructure can be easily and repeatedly molded, so that high throughput is obtained and it is economical, and since it is a nano-processing technology with less harmful waste, not only semiconductor devices in recent years, Application to various fields is expected.

  Such imprinting methods include a thermal imprinting method in which a concavo-convex pattern is transferred by heat using a thermoplastic resin, or a photoimprinting method in which a concavo-convex pattern is transferred by ultraviolet rays using a photocurable resin (for example, patents). Document 2) is known. As the resin as the transfer material, a thermoplastic resin is used in the thermal imprint method, and a photocurable resin is used in the photoimprint method. The optical imprint method can transfer a pattern at a low applied pressure at room temperature, and does not require a heating / cooling cycle like the thermal imprint method and does not cause dimensional changes due to the heat of the template or resin. It is said that it is excellent in terms of productivity.

  Templates used in the imprint method are required to have pattern dimension stability, chemical resistance, processing characteristics, and the like. In the imprint method, the pattern shape of the template must be faithfully transferred to a resin that is a transfer material. Therefore, in the case of the photoimprint method, generally, ultraviolet rays used for photocuring are transmitted. Quartz glass is used for the template.

  In the exposure process in the manufacturing process of a semiconductor device or the like, with the miniaturization of the element pattern, it is required to improve the accuracy of alignment (alignment) in which the upper element pattern is superimposed on the lower element pattern. Alignment is performed by measuring the arrangement state of the pattern layer already formed on the wafer, which is the substrate to be processed, and matching the shot position of the pattern layer to be exposed to the arrangement state of the pattern layer on the wafer. Is called. In order to enable such alignment, a wafer alignment mark is formed on each shot belonging to the pattern layer on the wafer.

  As alignment methods, there are die-by-die alignment and global alignment. Die-by-die alignment is a technique for aligning shots to be exposed for each shot belonging to a specific pattern layer already formed on a wafer. That is, the alignment mark formed in the shot of the specific pattern layer corresponding to the shot to be exposed is detected, and its coordinates are measured. This is a method for determining the position on the wafer of a shot to be exposed based on the measurement result. Alternatively, it is a method of detecting the shift by simultaneously detecting the alignment mark formed for each shot and the alignment mark formed on the template, and determining the exposure position so that the shift is minimized. On the other hand, global alignment detects the alignment marks of a plurality of specific shots selected from all shots belonging to a specific pattern layer already formed on the wafer, and the exposure position based on the alignment state of the alignment marks. Is an alignment technique for determining As described above, in principle, the die-by-die alignment performs alignment for each shot, so that the alignment accuracy of each shot is higher. However, in many cases, since many shots are performed, the total alignment time becomes longer.

  In the imprint method, in global alignment, a force is applied to the template at the time of imprinting each shot after alignment measurement, so it is difficult to hold the template position with high accuracy and the technical problem cannot be cleared. For this reason, die-by-die alignment is usually used, and a template alignment mark (alignment mark) for alignment is provided on the template together with the main pattern to be transferred.

  In the alignment process with the substrate to be processed (wafer) in the imprint process, alignment may be performed in a state where a resin is filled between the substrate and the template (referred to as in-line alignment). In the semiconductor manufacturing process, there is a space between shots (called a scribe portion), but the alignment mark needs to be formed in this scribe portion. In addition, it is necessary to prevent the scribe portion from being excessively processed and to be protected by a resist. Particularly in this case, the above-mentioned in-line alignment is necessary. When alignment is performed in this state, for example, an alignment mark is formed on a light-transmitting template such as quartz glass, and the substrate alignment mark formed on the substrate is observed through the template. However, even if the alignment mark is formed as a concavo-convex part by digging quartz glass in the template, if the resin exists between the substrate and the template and the resin enters the concave part, in the visible light region to be aligned Since there is almost no difference in refractive index between the quartz glass of the template and the resin, there has been a problem that it is difficult to detect the alignment mark made up of the concavo-convex portions and alignment is impossible.

  The above problem will be described in more detail. FIG. 7 shows an example of alignment with the wafer alignment mark 76 on the wafer 75 using the template 70 or 80 having the quartz glass digging type template alignment mark 73 or 83. In FIG. 7, FIG. 7A shows a case where there is no resin on the wafer 75, and alignment is possible (O). FIG. 7B shows a case where the resin 77 is formed on the wafer 75 but the wafer alignment mark 76 is not covered with the resin, and alignment is possible (◯). In FIG. 7C, the resin 77 is formed on the wafer 75 and the alignment mark 76 is covered with the resin 77, and the recess of the template alignment mark 73 is filled with the resin 77. Cannot (×). As shown in FIG. 7C above, when in-line alignment is necessary, the quartz glass digging alone does not function as an alignment mark.

  Therefore, it is necessary to give contrast to the alignment mark. An example in which a light-shielding film such as chromium is used as an alignment mark is well known (for example, see Patent Document 3). As shown in FIG. 7D, the resin 77 is formed on the wafer 75 and the alignment mark 76 is covered with the resin 77. However, the alignment mark 83 of the template 80 is a quartz glass digging type. However, in the case of the high-contrast alignment mark 83 with a high contrast in which a light-shielding film such as a chrome thin film is provided around the uneven mark, alignment is sufficiently possible (◯).

  Accordingly, the conventional alignment mark 83 shown in FIG. 7D is a desirable mark for highly accurate alignment. FIG. 8 is a schematic cross-sectional view showing a process of forming the conventional high contrast alignment mark shown in FIG. The alignment mark 83 is formed by forming a light-shielding thin film 84 such as chromium on one main surface of the quartz glass 81 (FIG. 8A) and forming a resist pattern 88 (FIG. 8B). The thin film 84 is etched, and then the quartz glass 81 is etched to provide a main pattern portion and an alignment mark portion (FIG. 8C). After the resist pattern 88 is removed, a second resist pattern 89 is formed ( 8D), the light-shielding thin film 84 other than the alignment mark portion is removed by etching (FIG. 8E), and the second resist pattern 89 is peeled off, and the template 80 having the alignment mark 83 is removed. Is formed (FIG. 8F).

  However, the conventional alignment mark formed of a light shielding film such as the above-mentioned chromium thin film has high contrast, but has insufficient cleaning resistance in the template cleaning process. There has been a problem that the film concentration decreases or disappears, and the function as an alignment mark cannot be performed.

  Since template cleaning is mainly performed on resin residue, which is an organic substance, SPM (mixed solution of sulfuric acid and hydrogen peroxide) cleaning is usually used for wet cleaning, and in the case of dry cleaning. In addition, oxygen gas, ozone gas, or the like is used using a parallel plate type or cylindrical type plasma ashing apparatus.

  FIG. 9 is an explanatory diagram showing a state in which when the template is peeled off after imprinting in the imprinting method, the resin remains as a resist on the main pattern side of the template, while a pattern dropout defect occurs on the transfer pattern side. is there. As shown in FIG. 9A, the alignment mark 83 of the template 80 and the alignment mark 76 on the wafer 75 are aligned, and the template 80 is pressed against the resin 77 to transfer the pattern. Next, as shown in FIG. 9B, the template 80 is peeled off, but the resin remains on the main pattern 82 side of the template to become the resin residue 92, while the transfer pattern 91 on the wafer 75 has a defect (plug). 93) may occur.

  Therefore, in the imprint method, the template cleaning process is an essential process for resetting the template to the initial clean state and forming a high-quality pattern. Was demanded.

JP-T-2004-504718 JP 2002-93748 A JP 2000-323461 A

  Therefore, the present invention has been made in view of the above problems. That is, an object of the present invention is to provide an imprint template provided with a high-contrast alignment mark having excellent cleaning resistance.

  The invention according to claim 1 of the present invention is a method in which a template having a concavo-convex pattern formed on one main surface of a light-transmitting substrate is pressed against a photocurable material on a substrate to be processed, and the photocuring is performed via the template. A template used for imprinting to transfer the concavo-convex pattern by photo-curing the photo-curable material by irradiating light that sensitizes the photosensitive material, on the convex portion of the concavo-convex pattern of the template, The template has a light shielding film pattern to be an alignment mark, and the upper surface and side surfaces of the light shielding film pattern are covered with a cleaning-resistant protective film.

  The invention according to claim 2 of the present invention is the template according to claim 1, wherein the cleaning-resistant protective film is also formed in the concave portion of the concave-convex pattern of the template.

  The invention according to claim 3 of the present invention is characterized in that the light-shielding film constituting the light-shielding film pattern is a chromium-based thin film, and the cleaning-resistant protective film is a silicon-based thin film. 2. The template according to 2.

  According to a fourth aspect of the present invention, when the cleaning resistance of the cleaning protection film is washed by ashing using oxygen gas in a state where the template is heated, the film of the cleaning resistance protection film The template according to any one of claims 1 to 3, wherein a thickness reduction rate is within 10% of an initial film thickness.

  According to the template of the present invention, since the light-shielding film pattern is protected during template cleaning, it is possible to perform highly accurate alignment while maintaining the quality of the template.

It is a cross-sectional schematic diagram of the template which has the alignment mark for imprint in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram of the template which has the alignment mark for imprint in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram of the template which has the alignment mark for imprint in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows the manufacturing process of the template which has the alignment mark for imprint in the 1st Embodiment of this invention of FIG. It is a cross-sectional schematic diagram which shows the manufacturing process of the template which has the alignment mark for imprint in the 2nd Embodiment of this invention of FIG. It is a cross-sectional schematic diagram which shows the manufacturing process of the template which has the alignment mark for imprint in the 3rd Embodiment of this invention of FIG. It is an example in the case of aligning with the wafer alignment mark on a wafer using the template which has the alignment mark of a quartz glass digging type. It is a cross-sectional schematic diagram which shows the manufacturing process of the template which has the conventional alignment mark for imprint. It is explanatory drawing which shows the subject in the imprint method which concerns on this invention.

  Hereinafter, an imprint alignment mark, a template including the alignment mark, and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a template having an imprint alignment mark according to the first embodiment of the present invention. In FIG. 1, an imprint template 10 includes a main pattern 12 for transferring to a photocurable material on a substrate to be processed, which is a concavo-convex pattern formed by digging one main surface of a light transmissive substrate 11, It consists of alignment marks 13.
The alignment mark 13 includes a concavo-convex pattern portion formed by digging the light transmissive substrate 11 and a light shielding film pattern 16 formed on the light transmissive substrate 11 of the concavo-convex pattern portion. Reference numeral 16 denotes a two-layer film including a light shielding film 14 and a cleaning-resistant protective film 15 provided on the light shielding film 14. In the present invention, the main pattern means a fine pattern of concavities and convexities that is pressed against a photo-curable material applied and formed on the surface of the substrate to be processed and transferred by mechanical deformation. Further, in the present invention, the photocurable material is a photocurable composition containing a photocurable resin that is usually used as a material for photoimprinting and a polymerizable monomer that is used in ink jet system coating. That means.

  In the present invention, examples of the material constituting the light-transmitting substrate 11 include optically polished synthetic quartz glass, soda glass, fluorite, and calcium fluoride. Synthetic quartz glass is used as a photomask substrate. Is more preferable because it has a proven track record and has a stable quality, and can provide an integrated light-transmitting structure by providing an uneven pattern, and a highly accurate fine uneven pattern can be formed.

  In the present invention, the light shielding film pattern 16 is composed of a two-layer film of a light shielding film 14 and a cleaning-resistant protective film 15 provided on the light shielding film 14. Uses a thin film material obtained by vacuum-depositing a chromium-based film, tantalum or the like, which has a predetermined optical density with respect to alignment light of visible light and is excellent in forming a fine pattern. Among these materials, a chromium-based film mainly composed of chromium, which has been used most for photomasks, is more preferable in terms of cost and quality of the template. For the chromium-based film, a material selected from chromium (Cr), chromium oxide (CrO), chromium nitride (CrN), chromium oxynitride (CrON), or the like is usually used. In order to increase the resolving power in pattern formation, the light shielding film itself is preferably a single layer film. In the present invention, the light-shielding film 14 also has a function as a mask material when the light-transmitting substrate 11 is etched to form uneven portions.

  Among the chromium-based materials, a chromium film or a chromium nitride film that is easy to form and highly versatile is preferable, and a chromium nitride film that can easily reduce film stress for forming a fine pattern is more preferable. For example, when a chromium nitride film is used as the light shielding film, the light shielding film is used with a film thickness in the range of about 5 nm to 10 nm. If the film thickness is less than 5 nm, it may be difficult to identify due to insufficient concentration in alignment, and if it exceeds 10 nm, it is not preferable for forming a fine pattern as an etching mask. As alignment light for alignment, visible light having a wavelength of 633 nm or the like is usually used.

  In the present invention, the cleaning-resistant protective film 15 constituting the light-shielding film pattern 16 is resistant to wet cleaning such as SPM cleaning (mixed solution of sulfuric acid and hydrogen peroxide solution), such as oxygen gas and ozone gas. A thin film material having high dry cleaning resistance is used. Among these materials, a silicon-based film is excellent in cleaning resistance and can easily form a fine pattern, and is preferable for protecting the underlying chromium-based film during cleaning. The silicon-based film is formed by vacuum deposition of silicon (amorphous; a-Si), silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), molybdenum silicide (MoSi), A material selected from thin films such as tantalum silicide (TaSi) and tungsten silicide (WSi) is used. In order to increase the resolving power in pattern formation, it is preferable to use a single-layer film as the cleaning resistant protective film itself.

  Among the above silicon-based materials, the silicon nitride film is more preferable because it has high resistance to both wet cleaning and dry cleaning. For example, when a silicon nitride film is used as a cleaning resistant protective film, the cleaning resistant protective film is used in a thickness range of about 5 nm to 10 nm. This is because when the film thickness is less than 5 nm, the resistance during cleaning is insufficient, and when it exceeds 10 nm, it is not preferable for forming a fine pattern as an etching mask.

In the present invention, the depth of the concave portion of the concavo-convex pattern formed by digging one main surface of the light transmissive substrate 11 depends on the desired pattern thickness of the resist pattern transferred and formed on the substrate to be processed. The depth of the concave portion of the concave / convex pattern is used in the range of 40 nm to 100 nm.
In the present invention, it is preferable that the depth of the concave portion of the concave and convex portion of the main pattern portion is the same as the depth of the concave portion of the concave and convex portion of the alignment mark portion. As will be described later, when the concave portion of the alignment mark of the present invention is formed simultaneously with the concave portion of the main pattern, the depth is the same.

  In the present invention, the shape of the alignment mark is not particularly limited, and a commonly used alignment mark shape can be applied corresponding to the alignment mark of the substrate to be processed. For example, it is possible to use a cross mark having a concave pattern of a concave / convex pattern having a cross shape with a width of 1 μm to 10 μm and a depth of 40 nm to 100 nm. A light-shielding film pattern having a width of 1 μm to 10 μm formed by a two-layer film of a cleaning protective film is provided, and the alignment mark can be formed by the concave cross mark and the light-shielding film pattern.

  The alignment mark of the present invention is a two-layer film provided with a cleaning-resistant protective film on the light-shielding film, so that the contrast is sufficiently high even in in-liquid alignment and high-precision alignment is possible. When the template for cleaning is cleaned, an alignment mark having excellent cleaning resistance is obtained, in which the alignment mark does not decrease in film thickness and the light shielding property does not deteriorate.

(Second Embodiment)
FIG. 2 is a schematic cross-sectional view of a template having imprint alignment marks in the second embodiment of the present invention. In FIG. 2, an imprint template 20 includes a main pattern 22 for transferring to a photocurable material on a substrate to be processed, which is a concavo-convex pattern formed by digging one main surface of a light transmissive substrate 21, It is comprised from the alignment mark 23. FIG.
The alignment mark 23 includes a concavo-convex pattern portion formed by digging the light transmissive substrate 21 and a light shielding film pattern 26 formed on the light transmissive substrate 21 of the concavo-convex pattern portion. The light shielding film pattern 26 is composed of a two-layer film of a light shielding film 24 and a cleaning resistant protective film 25 provided on the light shielding film 24, and the cleaning resistant protective film is also formed in the concave portion of the concave and convex pattern portion of the alignment mark 23. 25 is formed.

  In the present embodiment, the light-transmitting substrate 21, the light-shielding film 24 and the wash-resistant protective film 25 constituting the light-shielding film pattern 26 are used with the same material and film thickness as those in the first embodiment, and thus description thereof is omitted. In addition, the alignment mark has the same shape and dimensions as in the first embodiment. Since the cleaning-resistant protective film 25 provided in the concave portion of the concavo-convex pattern portion is formed in the same film forming process as the cleaning-resistant protective film 25 provided on the light shielding film 24 as will be described later, the manufacturing process is simplified. The same material as the washing-resistant protective film 25 provided on the light-shielding film 24 is preferable.

  The alignment mark of this embodiment is provided with a two-layer film by providing a cleaning-resistant protective film on the light shielding film, so that the contrast is sufficiently high even in in-line alignment, and high-precision alignment is possible. At the time of cleaning the printing template, the alignment mark is excellent in cleaning resistance so that the film does not decrease in film thickness and the light shielding property does not deteriorate.

  Further, since the alignment mark of the present embodiment is formed by etching and patterning the light shielding film and then forming a cleaning-resistant protective film, not only the upper surface side of the patterned light shielding film but also the side surfaces are constant. It will be covered with a thick cleaning-resistant protective film (not shown), and it can be an alignment mark with higher cleaning resistance.

(Third embodiment)
FIG. 3 is a schematic cross-sectional view of a template having imprint alignment marks in the third embodiment of the present invention. In FIG. 3, an imprint template 30 includes a main pattern 32 for transferring to a photocurable material on a substrate to be processed, which is a concavo-convex pattern formed by digging one main surface of a light transmissive substrate 31, and It is comprised from the alignment mark 33. FIG.
The alignment mark 33 includes a concavo-convex pattern portion formed by digging the light transmissive substrate 31 and a light shielding film pattern 36 formed on the light transmissive substrate 31 of the concavo-convex pattern portion. The light shielding film pattern 36 is composed of a two-layer film of a light shielding film 34 and a cleaning-resistant protective film 35 provided on the light shielding film 34, and the concave and convex patterns of the concave and convex pattern portion of the alignment mark 33 and the concave and convex pattern of the main pattern 32. A cleaning-resistant protective film 35 is also formed in the recess.

  In the present embodiment, the light-transmitting substrate 31, the light-shielding film 34 constituting the light-shielding film pattern 36, and the wash-resistant protective film 35 are used with the same material and film thickness as those in the first embodiment, and thus description thereof is omitted. In addition, the alignment mark has the same shape and dimensions as in the first embodiment. The cleaning resistant protective film 35 provided in all the concave portions of the concavo-convex pattern is formed in the same film forming process as the cleaning resistant protective film 35 provided on the light shielding film 34 as described later, thereby simplifying the manufacturing process. Therefore, the same material as the cleaning resistant protective film 35 provided on the light shielding film 34 is preferable.

  The alignment mark of this embodiment is provided with a two-layer film by providing a cleaning-resistant protective film on the light shielding film, so that the contrast is sufficiently high even in in-line alignment, and high-precision alignment is possible. At the time of cleaning the printing template, the alignment mark is excellent in cleaning resistance so that the film does not decrease in film thickness and the light shielding property does not deteriorate.

Furthermore, the alignment mark of the present embodiment is formed by an etching method by depositing a cleaning-resistant protective film on all the recesses of the main pattern used for transfer, and the corners on the bottom surface of the recesses that are likely to be sharp. The effect of relaxing the shape of the part and improving the releasability of the resin during imprinting can be obtained.
Next, a method for manufacturing a template having the above alignment mark will be described.

(Manufacturing method of the first embodiment)
FIG. 4 is a schematic cross-sectional view showing a manufacturing process of the template of the present invention having the alignment mark of the first embodiment shown in FIG. In FIG. 4, the same reference numerals are used to indicate the same parts as in FIG.

  A light-shielding film 14 such as chromium is formed on one main surface of the light-transmitting substrate 11 such as quartz glass, and then a cleaning-resistant protective film 15 is formed to form a two-layer film (FIG. 4A). ). A conventionally known sputtering method can be applied to form the light shielding film 14 and the cleaning resistant protective film 15.

  Next, a first electron beam resist is applied on the cleaning-resistant protective film 15, drawn with an electron beam, and developed to form a first resist pattern 18 having a main pattern and an alignment pattern (FIG. 4 ( b)).

  Next, using the first resist pattern 18 as a mask, dry-etching is performed in the order of the cleaning-resistant protective film 15, the light-shielding film 14, and the light-transmitting substrate 11, and the uneven pattern that becomes the main pattern 12 on the light-transmitting substrate 11. Then, a concavo-convex pattern as the alignment mark 13 is formed (FIG. 4C).

In the formation of the concavo-convex pattern in FIG. 4C, when the cleaning-resistant protective film 15 is a silicon-based thin film, a fluorine-based gas such as CF ₄ , CHF ₃ , C ₂ F ₆ or SF ₆ , C ₄ F ₈ , Alternatively, by using these mixed gases or a gas obtained by mixing oxygen in these gases as an etching gas, dry etching can be performed to form a pattern. At this time, if the light shielding film 14 in the lower layer of the two-layer film is a chromium-based thin film, it is resistant to fluorine-based gas, so that it has a function of an etching stop layer during dry etching of the upper cleaning-resistant protective film 15 It is.

When the light shielding film 14 is a chromium-based thin film, dry etching is performed using a mixed gas of chlorine (Cl ₂ ) and oxygen as an etching gas, and the cleaning resistant protective film 15 and the light transmissive substrate 11 are not damaged. A chrome pattern can be formed. Chlorine gas can be used in place of other chlorine-based gases such as CHCl ₃ , SiCl ₄ , and CCl ₄ .

When the light-transmitting substrate 11 is quartz glass, fluorine-based gas such as CF ₄ , CHF ₃ , C ₂ F _6, SF ₆ , C ₄ F ₈ , a mixed gas thereof, or oxygen in these gases By using a mixed gas as an etching gas, dry etching can be performed to form an uneven pattern.

  Next, after the first resist pattern 18 is peeled off, a second electron beam resist is applied, drawn with an electron beam, and developed to form a second resist pattern 19 for alignment marks (FIG. 4). (D)).

  Next, using the first resist pattern 19 as a mask, the cleaning resistance protection film 15 and the light shielding film 14 are dry-etched in this order to remove the cleaning resistance protection film and the light shielding film other than the alignment mark portion (FIG. 4 ( e)).

  Next, the second resist pattern 19 is peeled off, and the template 10 having the main pattern 12 composed of a concavo-convex pattern and the alignment mark 13 is obtained (FIG. 4F). The alignment mark 13 includes a concavo-convex pattern portion formed by digging a light-transmitting substrate and a light-shielding film pattern portion formed on the light-transmitting substrate of the concavo-convex pattern portion. It is composed of a two-layer film of a light shielding film 14 and a cleaning resistant protective film 15.

  According to the manufacturing method of the present embodiment, it is composed of an uneven pattern portion formed by digging a light-transmitting substrate and a light-shielding film pattern portion composed of a two-layer film of a light-shielding film and a wash-resistant protective film. A high-precision template having a positioning mark and having high cleaning resistance can be manufactured.

(Manufacturing method of the second embodiment)
FIG. 5 is a schematic cross-sectional view showing a manufacturing process of the template of the present invention having the alignment mark of the second embodiment shown in FIG. In FIG. 5, the same reference numerals are used to indicate the same parts as in FIG.

  A light shielding film 24 of chromium or the like is formed on one main surface of the light transmissive substrate 21 such as quartz glass (FIG. 5A). A conventionally known sputtering method can be applied to form the light shielding film 24.

  Next, a first electron beam resist is applied on the light shielding film 24, drawn with an electron beam, and developed to form a first resist pattern 28 having a main pattern and an alignment pattern (FIG. 5B). .

  Next, using the first resist pattern 28 as a mask, the light shielding film 24 and the light-transmitting base material 21 are dry-etched in this order, and the light-transmitting base material 21 is used as the concave / convex pattern and the alignment mark 23 that become the main pattern 22. An uneven pattern is formed (FIG. 5C).

5C, when the light shielding film 24 is a chromium-based thin film, dry etching is performed using a mixed gas of chlorine (Cl ₂ ) and oxygen as an etching gas, and the cleaning-resistant protective film 25 and The chromium pattern can be formed without damaging the light transmissive substrate 21. Chlorine gas can be used in place of other chlorine-based gases such as CHCl ₃ , SiCl ₄ , and CCl ₄ .

When the light-transmitting substrate 21 is quartz glass, a fluorine-based gas such as CF ₄ , CHF ₃ , C ₂ F _6, SF ₆ , C ₄ F ₈ , a mixed gas thereof, or oxygen in these gases By using a mixed gas as an etching gas, dry etching can be performed to form an uneven pattern.

  Next, after removing the first resist pattern 28, a cleaning-resistant protective film 25 is formed on the entire surface of the one main surface on which the concave / convex pattern of the light-transmitting substrate 21 is formed (FIG. 5D). . At this time, the cleaning-resistant protective film 25 is also formed in the recesses of the uneven pattern. A conventionally known sputtering method is used to form the cleaning resistant protective film 25.

  Next, a second electron beam resist is applied, drawn with an electron beam, and developed to form a second resist pattern 29 for alignment marks (FIG. 5E).

  Next, using the second resist pattern 29 as a mask, the unnecessary cleaning-resistant protective film 25 and light shielding film 24 other than the alignment mark portion are removed by dry etching (FIG. 5F).

  Next, the second resist pattern 29 is peeled off to obtain a template 20 having a main pattern 22 made of a concavo-convex pattern and an alignment mark 23 (FIG. 5G). The alignment mark 23 includes a concavo-convex pattern portion formed by digging a light-transmitting substrate and a light-shielding film pattern portion formed on the light-transmitting substrate of the concavo-convex pattern portion. It is composed of a two-layer film of a light shielding film 24 and a cleaning resistant protective film 25. A cleaning-resistant protective film 25 is also formed in the concave portion of the concave / convex pattern portion of the alignment mark 23.

  In the manufacturing method of the present embodiment, the washing-resistant protective film can be formed also on the side surface portion of the light-shielding film pattern by taking the step of forming the washing-resistant protective film after patterning the light-shielding film. By eliminating the exposed portion of the film pattern, it is possible to obtain an alignment mark having higher cleaning resistance.

(Manufacturing method of the third embodiment)
FIG. 6 is a schematic cross-sectional view showing a manufacturing process of the template of the present invention having the alignment mark of the third embodiment shown in FIG. In FIG. 6, the same reference numerals are used to indicate the same parts as in FIG.

  A light-shielding film 34 such as chromium is formed on one main surface of the light-transmitting substrate 31 such as quartz glass (FIG. 6A). A conventionally known sputtering method can be applied to form the light shielding film 34.

  Next, a first electron beam resist is applied onto the light-shielding film 34, drawn with an electron beam, and developed to form a first resist pattern 38 having a main pattern and an alignment pattern (FIG. 6B). .

  Next, using the first resist pattern 38 as a mask, the light shielding film 34 and the light-transmitting substrate 31 are dry-etched in this order to form the concave / convex pattern and the alignment mark 33 that become the main pattern 32 on the light-transmitting substrate 31. An uneven pattern is formed (FIG. 6C).

6C, when the light-shielding film 34 is a chromium-based thin film, dry etching is performed using a mixed gas of chlorine (Cl ₂ ) and oxygen as an etching gas, and the cleaning-resistant protective film 35 and A chromium pattern can be formed without damaging the light transmissive substrate 31. Chlorine gas can be used in place of other chlorine-based gases such as CHCl ₃ , SiCl ₄ , and CCl ₄ .

When the light-transmitting substrate 31 is quartz glass, fluorine-based gas such as CF ₄ , CHF ₃ , C ₂ F _6, SF ₆ , C ₄ F ₈ , a mixed gas thereof, or oxygen in these gases By using a mixed gas as an etching gas, dry etching can be performed to form an uneven pattern.

  Next, after removing the first resist pattern 38, a cleaning-resistant protective film 35 is formed on the entire main surface of the light-transmitting substrate 31 on which the concave / convex pattern is formed (FIG. 6D). At this time, the cleaning-resistant protective film 35 is also formed in the recesses of the uneven pattern. A conventionally known sputtering method is used to form the cleaning resistant protective film 35.

  Next, a second electron beam resist is applied, drawn with an electron beam, and developed to form a second resist pattern 39 for the alignment mark 33 and the main pattern 32 (FIG. 6E).

  Next, using the second resist pattern 39 as a mask, the cleaning-resistant protective film 35 and the light-shielding film 34 that do not require the alignment mark portion and the main pattern portion are removed by dry etching (FIG. 6F).

  Next, the second resist pattern 39 is peeled off to obtain a template 30 having a main pattern 32 made of a concavo-convex pattern and an alignment mark 33 (FIG. 6G). The alignment mark 33 includes a concavo-convex pattern portion formed by digging a light-transmitting substrate and a light-shielding film pattern portion formed on the light-transmitting substrate of the concavo-convex pattern portion. It is composed of a two-layer film of a light shielding film 34 and a cleaning resistant protective film 35. A cleaning-resistant protective film 35 is also formed in the concave portion of the concave / convex pattern portion of the alignment mark 33 and the concave portion of the concave / convex pattern portion of the main pattern 32.

  In the manufacturing method of the present embodiment, the washing-resistant protective film can be formed also on the side surface portion of the light-shielding film pattern by taking the step of forming the washing-resistant protective film after patterning the light-shielding film. By eliminating the exposed portion of the film pattern, it is possible to obtain an alignment mark having higher cleaning resistance. Furthermore, the cleaning-resistant protective film is deposited in all the concave portions of the main pattern used for transfer, thereby relaxing the corner shape of the bottom surface of the concave portions and improving the mold releasability during imprinting. Can be manufactured. Moreover, the familiarity of the resist with the pattern can be improved by controlling the properties of the protective film such as resist wettability and porosity. It is also possible to manufacture a template with improved filling properties.

(Manufacturing method of other embodiment)
In the template manufacturing method, in the second resist pattern formation, a method of forming a resist pattern by a photosensitive resist or a method of forming a resist pattern by an imprint method is used instead of electron beam drawing by an electron beam resist. It is also possible. According to the imprint method, there is an effect that the resist is sufficiently filled in the concave portions of the concave / convex pattern of the alignment mark.

  A chromium nitride film having a thickness of 10 nm was formed as a light-shielding film on quartz glass by a sputtering method, and then a silicon nitride film having a thickness of 5 nm was formed as a cleaning-resistant protective film to form a two-layer film. Next, a first electron beam resist was applied onto the silicon nitride film, drawn with an electron beam, and developed to form a first resist pattern having a main pattern and an alignment pattern.

Next, using the first resist pattern as a mask, the silicon nitride film is dry-etched sequentially with CF ₄ gas, the chromium nitride film is mixed with chlorine and oxygen, and quartz glass is CF ₄ gas. A concavo-convex pattern and a concavo-convex pattern were formed as alignment marks. The depth of the recesses of the concavo-convex pattern is 50 nm for both the main pattern and the alignment mark, the main pattern is a plurality of line and space patterns with a recess width of 30 nm and a pitch of 60 nm, and the alignment mark is a cross mark shape with a recess width of 2 μm. .

Next, after peeling off the first resist pattern, a second electron beam resist is applied, drawn with an electron beam, and developed to form a second resist pattern for alignment marks. Using the pattern as a mask, the silicon nitride film was dry-etched in order with CF ₄ gas and the chromium nitride film was mixed with chlorine and oxygen, and the silicon nitride film and the chromium nitride film other than the alignment mark portion were removed.

  Next, the second resist pattern was peeled off to produce a template having a main pattern composed of a concavo-convex pattern and an alignment mark. The alignment mark of the template of this embodiment is composed of an uneven pattern portion formed by digging quartz glass and a light shielding film pattern portion formed on the quartz glass of the uneven pattern portion, and the light shielding film pattern portion is shielded from light. It is composed of a two-layer film of a chromium nitride film as a film and a silicon nitride film as a cleaning resistant protective film.

  About the template of said Example, several samples (evaluation sample No. 1-4) were prepared and the following washing | cleaning tolerance evaluation test was done. For comparison, a template in which the alignment mark is composed only of a conventional chromium film (single layer) is prepared, and a plurality of samples (evaluation samples No. 5 to 7) are prepared. The cleaning resistance evaluation test was conducted. The template of the comparative example was made of the same material and configuration as the above examples except that the alignment mark was formed of a chromium film (single layer) having a thickness of 10 nm.

The evaluation test of the cleaning resistance was performed for the following three cleaning conditions A to C. A parallel plate type plasma ashing apparatus was used for ashing.
(A) After heating the template to 150 ° C. and ashing in an oxygen gas atmosphere for 5 minutes, the amount of change (%) in the thickness of the light shielding film pattern portion was measured.
(B) After heating the template to 250 ° C. and ashing in an oxygen gas atmosphere for 5 minutes, the amount of change (%) in the thickness of the light shielding film pattern portion was measured.
(C) After the template was wet washed with SPM (mixed solution of sulfuric acid and hydrogen peroxide solution), the amount of change (%) in the thickness of the light shielding film pattern portion was measured.
The amount of change in film thickness was measured by measuring the initial film thickness of the protective film on the light-shielding film before the cleaning resistance evaluation test and the film thickness after the cleaning test with an atomic force microscope. Rate).
The evaluation test results are shown in Table 1.

Evaluation sample Nos. As shown in 1-4, the template evaluation sample which consists of a two-layer film of the chromium nitride film and the silicon nitride film of the example is for ashing (dry cleaning) by oxygen gas, and for wet cleaning by SPM. The amount of change in film thickness (thickness reduction rate) was within several percent, and all showed high cleaning resistance.
On the other hand, evaluation sample Nos. 5-7, the template evaluation sample which consists of a conventional chromium single layer film has caused damage to the extent that the chromium film almost disappears by ashing with oxygen gas. Further, the chromium film concentration also decreased by wet cleaning with SPM.

  From the above test results, it is composed of a concavo-convex pattern portion formed by digging quartz glass and a light-shielding film pattern portion formed on the quartz glass of this concavo-convex pattern portion, and the light-shielding film pattern portion is chromium nitride as a light-shielding film The excellent cleaning resistance of the alignment mark of the template of the present invention composed of a two-layer film of a film and a silicon nitride film as a cleaning resistant protective film was confirmed.

10, 20, 30 Template 11, 21, 31 Light transmissive substrate 12, 22, 32 Main pattern 13, 23, 33 Alignment mark 14, 24, 34 Light shielding film 15, 25, 35 Wash-resistant protective film 16, 26, 36 Light-shielding film patterns 18, 28, 38 First resist pattern 19, 29, 39 Second resist pattern 70, 80 Template 72, 82 Main pattern 73, 83 Alignment mark 75 Wafer 76 Wafer alignment mark 77 Resin 81 Quartz glass 84 Light-shielding thin film 88, 89 Resist pattern 91 Transfer pattern 92 Resin residue 93 Defect

Claims (4)

By pressing a template having a concavo-convex pattern on one main surface of a light-transmitting substrate against a photocurable material on a substrate to be processed and irradiating light that sensitizes the photocurable material through the template A template used for imprinting by photocuring the photocurable material to transfer the concavo-convex pattern,
On the convex part of the concave-convex pattern of the template, it has a light-shielding film pattern serving as an alignment mark,
A template, wherein an upper surface and a side surface of the light shielding film pattern are covered with a cleaning-resistant protective film.   The template according to claim 1, wherein the cleaning-resistant protective film is also formed in a concave portion of the concave-convex pattern of the template.   The template according to claim 1 or 2, wherein the light shielding film constituting the light shielding film pattern is a chromium-based thin film, and the cleaning-resistant protective film is a silicon-based thin film.   The cleaning resistance of the cleaning resistant protective film is less than 10% of the initial film thickness when the template is heated and cleaned by ashing with oxygen gas. The template according to claim 1, wherein the template is any one of claims 1 to 3.

Images