JP2019197769A - Manufacturing method of substrate for imprint mold - Google Patents

Abstract

To provide a manufacturing method of a substrate for imprint mold which can significantly reduce the processing stress to a pattern formation part without excessive processes and costs.SOLUTION: A manufacturing method of a substrate for imprint mold subjected to outer shape processing, when performing outer shape processing of a substrate 1 for imprint mold which has a pattern formation part 2 and a non-pattern formation part 5 using a substrate processing pedestal 3, uses the substrate processing pedestal 3 having a recess, stores the pattern formation part 2 of the substrate 1 for imprint mold in the recess, provides a space area 7 between the pattern formation part 2 and the substrate processing pedestal 3, fixes the substrate 1 for imprint mold on the substrate processing pedestal 3 by sticking the non-pattern formation part 5 and the substrate processing pedestal 3 in the state where the pattern formation part 2 is not brought into direct contact with the substrate processing pedestal 3, and performs outer shape processing onto at least a portion of the substrate 1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing an imprint mold substrate.

In imprint technology, which is one of the alternative technologies for photolithography that has become popular in recent years, various shapes of substrates are used for molds used for imprinting, and the front surface, back surface, end surface, and chamfered portion of the substrate are used. There are many cases of processing.
The imprint technology is a technique that presses a mold with a micrometer or nanometer-size concavo-convex pattern on the surface of the substrate in advance against the work material or resin formed on the surface, and transfers the fine pattern precisely at once. is there. In particular, the UV nanoimprint is advantageous in synthetic quartz glass in terms of low thermal expansion, purity, heat resistance, and chemical resistance in IC applications where a fine pattern is required.

The imprint process has advantages such as cost reduction by shortening the process and high transfer reproducibility as compared with the conventional method. However, since the imprint process is performed by 1: 1 direct contact between the mold and the workpiece, there are various imprint processes. There are problems specific to imprinting that are not found in conventional photolithography, such as defects and the need for high shape accuracy of the entire mold.
In many cases, the concavo-convex marking included in the manufacturing process of the imprint mold is performed by a photolithography method and wet etching using an apparatus for manufacturing a semiconductor or the like. The pattern position accuracy in semiconductor manufacturing is required to be on the order of several hundreds to several nanometers, but not only the processing accuracy of fine patterns but also high-precision shapes are defined up to the front and back surfaces and end surfaces of the mold.

For example, in Patent Document 1, in the method of forming a non-through hole on the surface opposite to the mold pattern, there is no pattern on the surface opposite to the locus of the rotary processing tool during processing in the Z-axis direction when forming the non-through hole. A non-through hole is formed only in a part of the desired shape so as to pass through the surface. Next, by processing the non-through hole in the XY direction and expanding the non-through hole into a desired shape, when the trajectory of the rotary processing tool passes through the opposing surface of the pattern, the processing stress in the XY direction A method of reducing the damage to the pattern by directing the vector is described.
Further, Patent Document 2 describes a pattern formation portion protection technique for protecting against damage to a mold pattern formation portion due to grinding dust discharged during mold shaping.

JP 2011-245787 A JP2015-214449A

However, in the case of Patent Document 1, the stress at the time of processing in the Z-axis direction is applied to the entire surface including the pattern, and the stress on the pattern forming portion is not zero even at the time of processing in the XY direction. Further, since the pattern forming portion is directly pasted and fixed, damage caused by pasting or damage due to processing stress is inevitable.
Also, in Patent Document 2, although foreign matter contact from the outside such as grinding scraps is reduced, damage to processing cannot be avoided since the processing stress through the protective member has not been reduced.

  The present invention has been made in view of such circumstances, and provides a method for manufacturing an imprint mold substrate that can significantly reduce processing stress on a pattern forming portion without extra steps and costs. For the purpose.

  As a result of intensive studies to achieve the above object, the present inventors have provided a concave portion capable of accommodating the pattern forming portion of the imprint mold substrate in the substrate processing pedestal so that the pattern forming portion and the pedestal The present invention was completed by finding that the outer shape of the substrate can be processed while maintaining the non-contact state.

That is, the manufacturing method of the imprint mold substrate subjected to the outer shape processing according to the present invention performs the outer shape processing of the imprint mold substrate having the pattern forming portion and the non-pattern forming portion using the substrate processing base. The substrate processing base having a recess is used, and the pattern forming portion of the imprint mold substrate is accommodated in the recess, and a space region is provided between the pattern forming portion and the substrate processing base, thereby forming the pattern forming portion and the substrate. After the non-pattern forming part and the substrate processing base are pasted in a state where they are not in direct contact with the processing base and the imprint mold substrate is fixed to the substrate processing base, the outer shape processing is performed on at least a part of the substrate. Is to do.
In this way, by providing a space region between the pattern forming portion and the substrate processing base, damage, breakage, and micro defects of the pattern forming portion due to stress during outline processing are reduced, and micro defects are found in the pattern forming portion. Generation | occurence | production or a foreign material adhering can be prevented efficiently.

At this time, in the space region provided between the pattern forming portion and the substrate processing base, if the pattern forming portion and the substrate processing base are not in direct contact, there is no particular limitation on the distance between them, workability, From the viewpoint of process stability and the like, the separation distance in the XY direction is preferably at least 100 μm, particularly preferably 1 mm or more, and the upper limit is not particularly limited, but is preferably 10 mm or less, particularly preferably 5 mm or less.
From the same viewpoint, the Z-direction separation distance is preferably at least 10 μm, particularly preferably 50 μm or more.

  Furthermore, in order to avoid contact between the pattern forming part and the substrate processing base when the substrate processing base is removed before and after the outer shape processing, the substrate processing base can be detached from the base separately from the above-mentioned recesses. In addition, it is preferable to provide a movable part configured such that when it is removed, the concave part communicates with the end surface of the pedestal to form a concave groove. With such a configuration, the imprint mold substrate can be slid from the end surface of the pedestal and detached.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to avoid the process stress at the time of external shape processing, and the damage to the pattern formation part by contact support, and can provide the high quality imprint mold substrate by which the external shape process was carried out.

It is sectional drawing of the board | substrate for imprint molds used by one Embodiment of the manufacturing method of this invention. One Embodiment of the base for board | substrate processing used for the manufacturing method of this invention is shown, (A) is a top view, (B) is sectional drawing. It is a figure which concerns on one Embodiment of the manufacturing method of this invention, and is sectional drawing of the state which affixed the board | substrate for imprint molds on the base for board | substrate processing. It is a figure which concerns on one Embodiment of the manufacturing method of this invention, and is explanatory drawing which shows an example which carries out external shape processing of the back surface of the board | substrate for imprint molds. It is a top view concerning the modification of the base for substrate processing used for the manufacturing method of the present invention. It is a perspective view of the base for substrate processing which shows the modification of the base for substrate processing used for the manufacturing method of this invention, and has a movable part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an imprint having a rectangular shape in plan view, provided with a convex pattern forming portion 2 on the surface of which a fine uneven pattern (not shown) is used, which is used in an embodiment of the manufacturing method of the present invention. A cross-sectional view of the mold substrate 1 is shown.
The raw material substrate of the imprint mold substrate 1 is formed of a synthetic quartz glass into a desired shape, annealed, sliced to a desired thickness, and then ground on a surface and optionally polished on the outer periphery. Then, it is obtained through rough polishing and precision polishing.
After the raw material substrate thus manufactured is cleaned, a metal such as Cr, Cu, Mo, Ni, or a metal oxide film or a metal nitride film thereof is usually formed on the raw material substrate using a vapor deposition apparatus or a sputtering apparatus. Is laminated.
The film thickness to be laminated is preferably 200 nm or less, more preferably 10 to 50 nm.

  Next, a photoresist is applied onto the laminated metal, metal oxide film, or metal nitride film. The photoresist may be either a positive type or a negative type, but a positive type resist is preferably used from the viewpoint of accuracy and environment. Resist types corresponding to those for electron beam, EUV, ArF, KrF, I-line, and g-line are selected according to the exposure wavelength, and the resist is also a corresponding type. The resist film thickness can generally be selected in the range of several nm to several tens of μm. As the coating method, spin coating, spray coating, slit coating, or the like can be used, but spin coating is preferable because it can be applied more uniformly.

Subsequently, when an exposure machine is used, a photomask having a desired pattern and an alignment mark is set. When direct drawing is performed, desired pattern data is set.
In the case of an exposure machine, a raw material substrate in which the above-described metal, metal oxide film or metal nitride film and a resist film are stacked is set in an exposure machine, and exposure is performed through a photomask pattern. In general, a photomask having a size larger than that of the raw material substrate is used to cover the entire area to be exposed. The dimensions of the photomask and the raw material substrate are not particularly limited, but it is preferable to select one of 5-7 inch square and 9 inch square defined in SEMI standards.
In the case of direct drawing, an electron beam or a laser is used to aim only at a desired pattern formation place on a raw material substrate in which the above-mentioned metal, metal oxide or metal nitride film and a resist film are laminated using an electron beam or a laser beam. A pattern is formed by direct irradiation.
After exposure with an exposure amount corresponding to the resist type and resist film thickness, the resist film is developed, rinsed with pure water, and dried.

Thereafter, the metal film, the metal oxide film or the metal nitride film is etched by wet etching with a chromium etching solution, an acidic aqueous solution, an alkaline aqueous solution, or the like, or dry etching with a chlorine or fluorine-based gas, and the like, After obtaining a metal oxide or metal nitride pattern, the substrate is etched based on the pattern to obtain an imprint mold substrate 1 having a pattern forming portion 2 as shown in FIG.
Etching of the imprint mold substrate is performed using a wet etching method in which the imprint mold substrate is immersed in an etching aqueous solution containing hydrofluoric acid or sodium fluoride, and a fluorine-based gas that is converted into plasma by applying a high frequency. There is a dry etching method for performing etching.
In any method, the metal, metal oxide, or metal nitride pattern formation portion 2 is etched to etch the glass, so that the metal, metal oxide, or metal nitride pattern formation portion 2 is formed as shown in FIG. A structure having a convex shape is obtained.

Subsequently, an outer shape process is performed on at least a part of the imprint mold substrate 1 obtained above. This contour processing is intended to form a highly accurate shape required for an imprint mold substrate by performing contour processing into a desired shape. Specifically, it may be performed on at least a part of the substrate 1 for imprint molding, that is, on any one of the substrate surface, the back surface, the end surface, and the chamfered portion, or may be performed on these plural locations.
Since it is necessary to protect the pattern forming portion 2 of the imprint mold substrate 1 during the outer shape processing, it is preferable to provide a protective film that protects the pattern forming portion 2. As the protective film for protecting the pattern forming portion 2, a metal such as Cr, Cu, Mo, or Ni, an oxide or nitride film of these metals, or an organic compound photoresist film is used.

An imprint mold substrate 1 in which the pattern forming portion 2 is protected by a protective film (not shown) is fixed to a substrate processing base 3 shown in FIG. The substrate processing pedestal 3 can accommodate the pattern forming portion 2 in a manner that does not contact the substrate processing pedestal 3 so that the pattern forming portion 2 of the imprint mold substrate 1 does not directly contact the substrate processing pedestal 3. A concave portion 4 having a size and depth and having a rectangular shape in plan view is provided at substantially the center thereof. The material for the substrate processing base 3 is not particularly limited, and examples thereof include ceramics, glass, and metal.
The formation method of the said recessed part 4 is not specifically limited, About the board | substrate processing base 3, it cuts and forms larger than the said pattern formation part 2, or board | substrate processing from the raw material plate for bases which formed the recessed part 4 previously. The method of producing the pedestal 3 is mentioned. As a method for forming the recess 4, a known method such as cutting or etching can be used.

As shown in FIG. 3, the pattern forming portion 2 is accommodated in the concave portion 4, and the non-pattern forming portion 5 and the substrate processing pedestal 3 are bonded to each other via the adhesive member 6 to imprint mold. The substrate 1 is fixed to the substrate processing base 3. At this time, as the adhesive member 6, wax, epoxy, acrylic resin adhesive, UV curable resin, or the like is used.
In the present embodiment, since the recess 4 is provided in the substrate processing pedestal 3, as shown in FIG. 3, when the non-pattern forming portion 5 and the substrate processing pedestal 3 are pasted, the pattern forming portion A space region 7 is formed between 2 and the substrate processing base 3. As a result, damage, breakage, and microdefects of the pattern forming unit 2 due to stress during subsequent outer shape processing are reduced, and it is possible to prevent microdefects from occurring in the pattern forming unit 2 and foreign matters from adhering.

  The size of the space region 7 provided between the pattern forming unit 2 and the substrate processing pedestal 3 is not particularly limited unless the pattern forming unit 2 and the substrate processing pedestal 3 are in direct contact with each other. As described above, from the viewpoint of workability, process stability, etc., the distance in the XY direction is preferably at least 100 μm and at most 10 mm, more preferably at least 1 mm and at most 5 mm. Further, the distance in the Z direction is preferably at least 10 μm or more, and more preferably 50 μm or more.

After fixing the imprint mold substrate 1 to the substrate processing pedestal 3 by the above method, as shown in FIG. 4, using the rotary grindstone tool 9, the pattern forming surface, the front surface, the back surface, the end surface, the chamfered portion The outer shape is processed for at least part or all of the above.
This outer shape processing is often performed using an automatic processing machine such as a machining center in which a desired shape is programmed. In this case, the rotary grindstone tool 9 includes, for example, diamond, cubic boron nitride, etc. on the main axis of the automatic processing machine. Is fixed by electrodeposition or metal bond (not shown).
The rotational speed of the spindle of the rotating grindstone tool 9 is preferably 100 to 30,000 rpm, more preferably 1,000 to 15,000 rpm, from the viewpoint of processing accuracy and productivity. The grinding speed is preferably 1 to 10,000 mm / min, more preferably 10 to 1,000 mm / min, from the viewpoint of processing accuracy and productivity.
Further, for cooling and removal of chips, it is preferable to carry out the processing with an emulsion, water-soluble or oil-based cutting fluid.

As shown in FIG. 4, when externally processing the back surface of the imprint mold substrate 1 having the pattern forming portion 2 on the front surface, the Z direction (the lower direction in FIG. 4) when processing the non-through hole 10. ) Exceeds the destructive stress of the imprint mold substrate 1, the imprint mold substrate 1 may be cracked or broken in the space region 7 portion not in contact with the substrate processing base 3. In such a case, the shape of the rotary grindstone tool 9 used for the outer shape processing is designed to facilitate chip discharge, a sharp grindstone material, and a combination of conditions such as mild processing conditions. The processing conditions can be such that the fracture stress is not exceeded. In addition, when the outer shape processing area is larger than the non-contact area including the pattern forming unit 2, processing is performed so that a part of the locus of the rotary grindstone tool 9 during the outer shape processing always passes directly behind the contact area. By doing this, the processing stress in the Z direction during processing can be suppressed, and the fracture stress can be prevented from exceeding.
The external shape processing may include substrate size, end surface processing for improving the flatness of the end surface, and chamfered portion processing between the front surface or the back surface and the end surface that protrudes from the pedestal. And a cutting fluid.

Since the imprint mold substrate subjected to the outer shape processing in this way is often non-mirror surface, mirror polishing is performed as necessary to improve the strength of the processed portion, the cleanliness, the residual stress, and the like.
As a method, polishing is performed by moving one or both of the rotary polishing pad and the rotary polishing pad so that the rotary polishing pad is relatively rocked while the rotary polishing pad is in contact with the imprint mold substrate at a constant pressure. Preferably it is done.
The rotary polishing pad may be impregnated with an abrasive, but it is preferable to perform the processing in a state where a polishing abrasive slurry is interposed. The material of the polishing part of the rotary polishing pad is not limited as long as it can process and remove the work piece such as foamed polyurethane, cerium oxide impregnated polyurethane, zirconium oxide impregnated polyurethane, nonwoven fabric, suede, rubber, wool felt, etc. .
Examples of the abrasive grains when performing polishing with the abrasive grain slurry interposed include silica, ceria, alundum, white alundum (WA), FO, zirconia, SiC, diamond, titania, germania, and the like. The particle size is preferably 10 nm to 10 μm, and these water slurries can be suitably used.
In addition, as a method of pressing the rotating polishing pad against the side surface of the substrate to be polished with a constant pressure, a method using a pressurizing mechanism such as a pneumatic piston or a load cell can be cited.

In addition, the shape of each member used in the method for manufacturing an imprint mold substrate subjected to the outer shape processing according to the present invention is not limited to the above-described embodiment, and the scope of achieving the objects and effects of the present invention. Modifications and improvements in the above are included in the present invention.
That is, in the above-described embodiment, the substrate processing base 3 having a rectangular shape in plan view having the concave portion 4 having a rectangular shape in plan view is used. However, the substrate processing base 3 is not limited to this shape, and as shown in FIG. Depending on the shape of the substrate for imprint molding and the pattern forming portion, a circular shape in plan view, or a combination of a circular shape and a rectangular shape in plan view may be combined, and other shapes may be adopted as necessary. Good.

  Further, in order to avoid contact between the pattern forming portion and the substrate processing pedestal when the substrate processing pedestal is attached and detached before and after the outer shape processing, as shown in FIG. The substrate processing pedestal 3 may be used that has a movable portion 8 that is detachable from the pedestal 3 and that is configured so that the recessed portion 4 communicates with the end surface of the pedestal 3 to form a recessed groove when removed. With such a configuration, there is an advantage that the imprint mold substrate can be slid and detached from the end surface of the pedestal.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.
[Example 1]
A synthetic quartz glass substrate (imprint mold substrate 1) having a pattern forming portion 2 at the center 30 mm square of a synthetic quartz glass substrate having a size of 152 × 152 mm and a thickness of 6.35 mm, and a central 35 mm square range is engraved by 1 mm. A substrate processing base 3 having 140 × 140 mm and a thickness of 10 mm having a concave portion 4 was prepared.
The non-pattern forming portion 5 and the substrate processing pedestal 3 are made of rosin-based synthetic wax as the adhesive member 6 so that a space region 7 is provided between the pattern forming portion 2 of the synthetic quartz glass substrate and the substrate processing pedestal 3. Pasted.
Next, in order to externally process a non-through hole on the back surface of the synthetic quartz glass substrate, the center of the rotary grindstone tool 9 is set to the center of the non-through hole to be processed using a 32 mmφ rotary polishing grindstone tool 9. It circulated while keeping the state shifted by 16 mm. Thereby, a non-through hole 10 of 64 mmφ was formed. At this time, the rotary grindstone tool 9 was processed such that the non-contact portion between the substrate processing base 3 and the surface of the synthetic quartz glass substrate and the back side of the contact portion were always in contact.
As a result, a non-through hole 10 having a diameter of 64 mm, a depth of about 5.5 mm, and a remaining thickness of about 1 mm was processed on the back surface of the synthetic quartz glass substrate.
When the imprint mold substrate subjected to the outer shape processing was cleaned and a micro defect was measured using an automatic defect inspection apparatus, none of the surfaces including the pattern forming portion 2 was damaged.

[Comparative Example 1]
A synthetic quartz glass substrate of the same raw material as in Example 1 was attached to a flat substrate processing pedestal that was not processed with a step using the rosin synthetic wax.
Next, after performing the same processing as in Example 1, cleaning was performed, and a minute defect was measured using an automatic defect inspection apparatus. It was done. Moreover, the chip | tip was seen in the edge of a pattern formation part.

DESCRIPTION OF SYMBOLS 1 Imprint mold substrate 2 Pattern formation part 3 Substrate processing base 4 Recessed part 5 Non-pattern formation part 6 Adhesive member 7 Space area 8 Movable part 9 Rotary grindstone tool 10 Hole

Claims (2)

A method for manufacturing an imprint mold substrate subjected to outer shape processing, which performs outer shape processing of an imprint mold substrate having a pattern forming portion and a non-pattern forming portion using a substrate processing base,
The substrate processing pedestal has a recess, and in the recess, the pattern forming portion of the imprint mold substrate is accommodated, and a space region is provided between the pattern forming portion and the substrate processing pedestal. The imprint mold substrate is fixed to the substrate processing pedestal by pasting the non-pattern forming portion and the substrate processing pedestal in a state where the forming portion and the substrate processing pedestal are not in direct contact with each other. A method of manufacturing an imprint mold substrate subjected to contour processing, wherein contour processing is performed on at least a part.   2. The imprint mold substrate according to claim 1, wherein a separation distance between the pattern forming portion in the XY direction and the substrate processing base in the space region is at least 100 μm or more, and a separation distance in the Z direction is at least 10 μm or more. Manufacturing method.

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