JP6668714B2 - Injection mold release test method - Google Patents

Description

The present invention relates to a method for forming a pattern using an imprint technique in a manufacturing process of various products such as semiconductor devices, optical components such as optical waveguides and diffraction gratings, analysis chips related to biotechnology and chemistry, and recording media such as hard disks and DVDs. about releasability of molding de imprint testing methods used in.

  Hitherto, lithography technology has been used for nano-level fine processing such as LSI circuit patterns. In recent years, with the increase in integration, a technique for producing a finer pattern has been required, and the wavelength of an exposure light source has been reduced. However, changing the exposure light source requires enormous costs due to the introduction of manufacturing equipment and the development of peripheral technologies, making it difficult to proceed with development quickly.

  Under such circumstances, attention has been paid to an imprint technology that can easily perform nano-level fine processing in the manner of a stamp. Since imprint technology can be applied to resin processing, it has a wide range of applications in the electronics field, biotechnology field, and the like. For example, when manufacturing a semiconductor device or a recording medium, a method of forming a resin layer having a fine concavo-convex pattern transferred on the surface of a substrate (workpiece) is disclosed in Stephan Y. et al. Have proposed a method of forming a concavo-convex pattern on a resin layer by an imprint method (Non-Patent Document 1). In this imprint method, the irregularities of the mold are transferred to the resin layer by pressing the nanometer-sized irregularities formed on the original (mold) against the resin layer on the surface of the base material.

  The main imprinting methods include a thermal imprinting method, an optical imprinting method, and a room temperature imprinting method due to differences in processing processes and materials. In particular, the optical imprint method of forming a pattern with a UV-curable resin is often applied to a mass production process together with a roll-to-roll (RtoR) method capable of continuous transfer.

  In the RtoR method, a cylindrical roll is used as an original. If the desired pattern size is several tens of microns or more, the pattern may be directly processed on the roll surface by cutting, but if the size is submicron, cutting cannot be used. Therefore, a resin mold or a Ni electroformed mold is duplicated from a master mold made of quartz or silicon manufactured by using lithography using an electron beam, and the mold is wound around a roll and used as an original.

  Since these nickel electroforming molds and resin molds are both methods for transferring a pattern by directly contacting a medium to be transferred such as a film, the mold releasability between the mold and the UV-curable resin is important for producing a good product. This is an important point. In order to improve mold releasability, in the case of a nickel electroformed mold, a fluorine-based release layer is formed on the surface of the mold, and in the case of a resin mold, a resin in which a fluorine-based release component is kneaded. There is a countermeasure such as using.

  However, these countermeasures are not perfect, and the releasability lowers due to repeated transfer. Once the UV curable resin is clogged in the mold, the transferred product becomes defective. Therefore, it is necessary to quickly find out the deterioration of the mold release performance during mass production.

  As a method for evaluating the mold release performance of a mold, a contact angle measurement described in Non-Patent Document 2 is simple and general. Patent Literature 1 discloses measurement of frictional force and adhesive force using a scanning probe microscope. However, in these measurements, it is necessary to temporarily suspend mass production and remove the mold from the roll, which is not preferable in terms of throughput.

  As a solution to this, an auxiliary pattern that is likely to cause mold release failure is formed in the mold in advance, and a defect inspection device using a line sensor camera is used to check in real time during mass production whether there is a defect in the dummy pattern formed on the transferred product. An inspection method is conceivable. If this method is used, it is possible to indirectly evaluate the mold releasability by inspecting the transcript. Therefore, the mold release performance is deteriorated, and there is no need to stop the mass production line unless it is necessary to replace the mold with a new one.

Patent No. 5315973

Stephen Y. Chou "Imprint of sub 25 nm vias and trenches in polymers", Applied Physics Letters, 67 (21), (1995), 3114-6. Yoshihiko Hirai, "Basics, Technology Development and Application Development of Nanoimprint: Basic Technology of Nanoimprint and Latest Technology Development," Frontier Publishing, p29-30

  The present invention can inspect the mold releasability of a mold without stopping a mass production line by inspecting a dummy pattern formed by transferring an auxiliary pattern onto a transfer object for the presence or absence of a defect. An object of the present invention is to provide a printing mold and a method for inspecting the mold releasability of the mold.

The present invention is a releasability inspection method for inspecting releasability between a mold and a transfer-receiving medium, comprising: a base material; a main pattern provided on the surface of the base material and having a fine structure; A step of producing an imprint mold having an auxiliary pattern that is provided outside the region, has a fine structure, and is discontinuous in the feed direction of the medium to be transferred, and winding the imprint mold around a roll. , A step of preparing a roll mold, a step of applying an ultraviolet-curable resin to the surface of the transfer-receiving medium to form an ultraviolet-curable resin layer, and irradiating ultraviolet rays with the roll mold pressed against the ultraviolet-curable resin layer to, and transferring the main pattern and the auxiliary pattern ultraviolet curing resin layer, Damipata formed by transferring an auxiliary pattern to the ultraviolet-curing resin layer Based on the presence or absence of emission of a defect, and a step of examining releasability of the imprint mold, a releasing property testing method.

  According to the present invention, it is possible to inspect the mold releasability of a mold without stopping a mass production line by inspecting a dummy pattern formed by transferring an auxiliary pattern onto an object to be transferred for defects. A simple imprint mold and a method for inspecting the mold releasability of the mold can be realized.

FIG. 2 is a developed plan view of the imprint mold according to the embodiment of the present invention. It is sectional drawing which shows an example (a nickel electroforming mold) of the mold for imprint which concerns on embodiment of this invention. It is sectional drawing which shows another example (resin mold) of the mold for imprint which concerns on embodiment of this invention. FIG. 2 is a schematic configuration diagram illustrating an example of an auxiliary pattern according to an embodiment of the present invention, and a cross-sectional view taken along a cutting line B-B ′. FIG. 5 is a schematic configuration diagram illustrating a defect of an auxiliary pattern according to the embodiment of the present invention, and is a cross-sectional view taken along a cutting line B-B ′ illustrated in FIG. It is the schematic block diagram which shows another example of the auxiliary pattern which concerns on embodiment of this invention, and sectional drawing which follows the cutting-plane line C-C '. FIG. 3 is a schematic configuration diagram illustrating a general auxiliary pattern and a cross-sectional view along a cutting line D-D ′. It is a schematic structure figure showing the mold release inspection method concerning the embodiment of the present invention.

  Hereinafter, an example of an embodiment of the imprint mold of the present invention will be described with reference to FIGS. 1, 2, and 3. FIG.

  FIG. 1 is a developed plan view of an imprint mold according to an embodiment of the present invention. As shown in FIG. 1, an imprint mold 400 according to an embodiment of the present invention includes a main pattern 200 provided on the surface of a base material 100 inside a main pattern formation region 201, and a main pattern formation region 201 This is a structure including an auxiliary pattern 300 provided inside an auxiliary pattern formation region 301 located outside.

  The imprint mold 400 is copied from a quartz or silicon master mold in which a reverse pattern of a desired fine pattern (a pattern formed on the imprint mold) is formed by electron beam lithography.

  Since the imprint mold 400 is used by being wound around a roll by the RtoR method, the base material 100 is made of a material having some flexibility. The material of the base material 100 may be any material as long as a fine pattern can be reproduced, and examples thereof include nickel and resin.

  Hereinafter, an example of a method for manufacturing the imprint mold 400 will be described for a case of a nickel electroformed mold and a case of a resin mold.

  FIG. 2 is a cross-sectional view of an example of an imprint mold (a nickel electroformed mold) according to the embodiment of the present invention, and is a cross-sectional view corresponding to a section line A-A ′ shown in FIG. 1. As shown in FIG. 2, the nickel electroformed mold 401 includes a main pattern 200 and an auxiliary pattern 300 on the surface of the nickel base material 101.

<Production method by duplication of nickel electroformed mold>
First, a quartz master mold on which an inverted pattern of a desired fine pattern is formed by electron beam lithography is prepared. Next, nickel is formed as a seed layer on the surface of the master mold by a vacuum evaporation method. The thickness of the seed layer is about 100 nm to 1 μm. Next, it is immersed in a nickel plating solution, and the thickness is adjusted by the immersion time. The thickness of the nickel base material 101 shown in FIG. 2 is such that it can be easily wound around a roll and can maintain a certain level of durability, and is, for example, about 50 to 500 μm. By such a method, the nickel electroformed mold 401 on which the main pattern 200 and the auxiliary pattern 300 are formed is obtained.

  FIG. 3 is a cross-sectional view illustrating another example (resin mold) of the imprint mold according to the embodiment of the present invention, and is a cross-sectional view corresponding to a section line A-A ′ illustrated in FIG. 1. As shown in FIG. 3, the resin mold 402 includes a main pattern 200 and an auxiliary pattern 300 on the surface of the resin layer 102 formed on the base material 103.

<Production method by duplication of resin mold>
First, a quartz master mold on which an inverted pattern of a desired fine pattern is formed by electron beam lithography is prepared. Next, a PET film capable of transmitting UV light (for example, Cosmoshine manufactured by Toyobo) is used as a base material 103, and a UV curable resin layer 102 is formed on the surface of the base material 103 by a die coating method, an inkjet method, or the like. The thickness of the resin layer 102 is about 500 nm to 50 μm. The UV curable resin used for the resin mold contains a component for lowering the surface energy in order to improve the releasability from the transferred resin. Next, the pattern forming surface of the master mold is pressed onto the UV curable resin layer 102, and UV light is irradiated from the master mold side, thereby obtaining the resin mold 402 on which the main pattern 200 and the auxiliary pattern 300 are formed.

  The auxiliary pattern 300 is formed inside the auxiliary pattern formation area 301, and the auxiliary pattern formation area 301 is located outside the main pattern formation area 201. In order to improve the detection speed and sensitivity of the defect inspection machine as much as possible, it is preferable that the area scanned by the line sensor camera is small. More preferably, in order to detect only the dummy pattern portion, the main pattern forming region 201 and the auxiliary pattern forming region 301 are arranged so as not to be mixed in the feeding direction of the transfer medium.

  Further, if the main pattern forming area 201 and the auxiliary pattern forming area 301 are arranged so as not to be mixed, the auxiliary pattern 300 can be cut off by a cutting process to obtain an object to be transferred composed only of the main pattern 200. .

  Next, the auxiliary pattern 300 according to the present embodiment will be described with reference to FIGS. FIG. 4 is a schematic configuration diagram illustrating an example of an auxiliary pattern according to the embodiment of the present invention and a cross-sectional view along a cutting line BB ′. FIG. 5 illustrates defects of the auxiliary pattern according to the embodiment of the present invention. 6 is a cross-sectional view taken along a cutting line BB ′ shown in FIG. 4A, and FIG. 6 is a schematic diagram showing an auxiliary pattern and a cutting line C according to the embodiment of the present invention. 7 is a schematic configuration diagram showing a general auxiliary pattern and a cross-sectional view taken along a cutting line DD ′.

  The auxiliary pattern 300 is formed in a shape in which a defect is easily generated so that deterioration of the mold releasability can be quickly detected. Specifically, the shape is such that the surface continuous in the feed direction of the transfer-receiving medium is eliminated so that the stress applied to the pattern at the time of releasing the mold is increased. For example, as shown in FIG. 4A, a pattern in which a line and a space (L & S) extending in a direction orthogonal to the feed direction of the transfer medium are arranged at a ratio of 1: 1 in the feed direction of the transfer medium is used as an auxiliary pattern. When this auxiliary pattern is transferred, there is a tendency that projections 310 and pattern peeling as shown in FIG. For example, as shown in FIG. 6A, a dot-shaped pattern may be used as an auxiliary pattern. On the other hand, in the case of a shape having a continuous surface in the feeding direction of the medium to be transferred as shown in FIG. 7A, the protrusion 310 and the pattern peeling are less likely to occur. Therefore, the auxiliary pattern 300 may be configured by L & S or dot shape as shown in FIGS.

  The size of the auxiliary pattern 300 may include at least a pattern of a size that can be detected by the defect inspection machine. The resolution of the defect inspection machine varies greatly depending on the transfer speed of the transfer medium and the performance of the line sensor camera, but the transfer speed of the transfer medium is 10 to 100 m / min, the number of pixels is 8192 bits, and the driving frequency is 320 kHz. When a line sensor camera is used, the resolution is about 3 to 100 μm. Therefore, it suffices that a pattern such as L & S or dot shape of about 3 to 100 μm is included.

  Next, a method for inspecting the release performance of the imprint mold 400 of the present invention will be described with reference to FIG. FIG. 8 is a schematic configuration diagram illustrating a releasability inspection method according to the embodiment of the present invention.

  First, as preparation before transfer, the imprint mold 400 is wound around a roll using an adhesive or a tape to form a roll mold 501. As the transfer medium 600, for example, a transparent film having a high UV transmittance such as Cosmoshine (registered trademark) manufactured by Toyobo is used.

  Next, a UV curable resin is coated on the surface of the transfer target medium 600 by the resin discharge unit 502. The thickness of the resin depends on the pattern size to be processed, but is about 1 to 20 μm. Next, in a state where the roll mold 501 is pressed against the UV curable resin on the surface of the transfer target medium 600, UV light having a wavelength of 400 nm or less is irradiated using a UV light source 503 such as a high-pressure mercury lamp to cure the UV curable resin. Thus, a pattern is formed on the surface of the transfer-receiving medium 600.

  Thereafter, the line sensor camera 701 scans the dummy pattern of the transfer-receiving medium 600 on which the pattern is formed, and the inspection result display unit 702 displays the presence or absence of a defect such as an abnormal pattern shape, peeling, or chipping.

  When the defect is displayed as “present”, mass production is stopped, and the imprint mold 400 whose demolding performance has deteriorated is replaced with a new one.

  According to the imprint mold according to the present embodiment, since the auxiliary pattern has a discontinuous shape in the feed direction of the transfer medium, defects such as pattern peeling appear in the dummy pattern transferred to the transfer medium. Cheap. Therefore, according to the method for inspecting the releasability of the imprint mold according to the present embodiment, the mass production line is determined based on the presence or absence of a defect in the dummy pattern formed by transferring the auxiliary pattern to the resin layer of the transfer-receiving medium. Because the mold release property of the imprint mold can be inspected without stopping, the imprint mold can be replaced with a new one at the optimal timing before the transfer failure of the main pattern occurs. , Leading to an improvement in yield.

  Examples of the imprint mold of the present invention and a method of inspecting the mold releasability of the mold will be described below. However, the present invention is not limited to the embodiments.

(Example 1)
First, a quartz master mold in which a desired reverse pattern of the main pattern 200 and the auxiliary pattern 300 was formed by electron beam lithography was prepared. Next, nickel having a thickness of 200 nm was formed as a seed layer on the surface of the master mold by a vacuum evaporation method. Next, it was immersed in a nickel plating solution for 180 minutes to obtain a nickel electroformed mold 401 having a thickness of 150 μm.

  The main pattern 200 was a random pattern of about 100 nm to 1 μm, and the auxiliary pattern 300 was a 1: 1 L & S pattern extending in a direction orthogonal to the transfer medium transfer direction as shown in FIG. The L & S sizes were 100 nm, 500 nm, 1 μm, 5 μm, 10 μm, 50 μm, and 100 μm.

  Next, as preparation before transfer, a release agent (Optur HD-2100 made by Daikin) was dip-coated to form a release layer on the surface of the nickel electroformed mold 401. Subsequently, the nickel electroformed mold 401 was wound and adhered with an adhesive so that no gap was formed between the roll and the nickel electroformed mold 401, thereby forming a roll mold 501. Subsequently, Cosmoshine (registered trademark) manufactured by Toyobo and PAK02 (manufactured by Toyo Gosei) were prepared as a transfer medium 600 and a UV curable resin.

  Next, a UV curable resin having a film thickness of 1 μm is ejected from the resin ejection unit 502 of the transfer device 510 onto the surface of the transfer medium 600 by inkjet, and then the roll mold 501 is pressed against the UV curable resin on the surface of the transfer medium 600. In this state, a pattern was formed on the surface of the transfer-receiving medium 600 by irradiating UV light using a high-pressure mercury lamp as the UV light source 503 to cure the UV-curable resin. At this time, the feeding speed of the medium to be transferred was 10 m / min.

  Thereafter, a dummy pattern of the transfer-receiving medium 600 on which the pattern was formed was scanned by a line sensor camera 701 having a pixel count of 8192 bits and a driving frequency of 320 kHz. After the number of transfers of the roll mold 501 passed 10,000 times, a defect in which the pattern was peeled was displayed on the inspection result display unit 702. Therefore, mass production was stopped, and the imprint mold 400 whose mold release performance was deteriorated was replaced with a new one. . Observation of the main pattern transferred to the transfer-receiving medium 600 before the mass production was discontinued with an optical microscope showed no defects such as pattern peeling. As a result, all the transferred materials obtained before the mass production was discontinued and after the mass production was resumed were good. became.

(Example 2)
First, a quartz master mold in which a desired reverse pattern of the main pattern 200 and the auxiliary pattern 300 was formed by electron beam lithography was prepared. Next, nickel having a thickness of 200 nm was formed as a seed layer on the surface of the master mold by a vacuum evaporation method. Next, it was immersed in a nickel plating solution for 180 minutes to obtain a nickel electroformed mold 401 having a thickness of 150 μm.

  The main pattern 200 was a random pattern of about 100 nm to 1 μm, and the auxiliary pattern 300 was a 1: 1 dot pattern as shown in FIG. The dot size was 100 nm, 500 nm, 1 μm, 5 μm, 10 μm, 50 μm, and 100 μm.

  Next, as preparation before transfer, a release agent (Optur HD-2100 made by Daikin) was dip-coated to form a release layer on the surface of the nickel electroformed mold 401. Subsequently, the nickel electroformed mold 401 was wound and adhered with an adhesive so that no gap was formed between the roll and the nickel electroformed mold 401, thereby forming a roll mold 501. Subsequently, Cosmoshine (registered trademark) manufactured by Toyobo and PAK02 (manufactured by Toyo Gosei) were prepared as a transfer medium 600 and a UV curable resin.

  Next, a UV curable resin having a film thickness of 1 μm is ejected from the resin ejection unit 502 of the transfer device 510 onto the surface of the transfer medium 600 by inkjet, and then the roll mold 501 is pressed against the UV curable resin on the surface of the transfer medium 600. In this state, a pattern was formed on the surface of the transfer-receiving medium 600 by irradiating UV light using a high-pressure mercury lamp as the UV light source 503 to cure the UV-curable resin. At this time, the feeding speed of the medium to be transferred was 10 m / min.

  Thereafter, a dummy pattern of the transfer-receiving medium 600 on which the pattern was formed was scanned by a line sensor camera 701 having a pixel count of 8192 bits and a driving frequency of 320 kHz. After the number of transfers of the roll mold 501 passed 10,000 times, a defect in which the pattern was peeled was displayed on the inspection result display unit 702. Therefore, mass production was stopped, and the imprint mold 400 whose mold release performance was deteriorated was replaced with a new one. . Observation of the main pattern transferred to the transfer-receiving medium 600 before the mass production was discontinued with an optical microscope showed no defects such as pattern peeling. As a result, all the transferred materials obtained before the mass production was discontinued and after the mass production was resumed were good. became.

(Comparative Example 1)
First, a quartz master mold in which a desired reverse pattern of the main pattern 200 and the auxiliary pattern 300 was formed by electron beam lithography was prepared. Next, nickel having a thickness of 200 nm was formed as a seed layer on the surface of the master mold by a vacuum evaporation method. Next, it was immersed in a nickel plating solution for 180 minutes to obtain a nickel electroformed mold 401 having a thickness of 150 μm.

  The main pattern 200 was a random pattern of about 100 nm to 1 μm, and the auxiliary pattern 300 was a 1: 1 L & S pattern arranged in parallel to the transfer medium transfer direction as shown in FIG. The L & S sizes were 100 nm, 500 nm, 1 μm, 5 μm, 10 μm, 50 μm, and 100 μm.

  Next, as preparation before transfer, a release agent (Optur HD-2100 made by Daikin) was dip-coated to form a release layer on the surface of the nickel electroformed mold 401. Subsequently, the nickel electroformed mold 401 was wound and bonded with an adhesive so that no gap was formed between the roll and the nickel electroformed mold 401, thereby forming a roll mold 501. Subsequently, Cosmoshine (registered trademark) manufactured by Toyobo and PAK02 (manufactured by Toyo Gosei) were prepared as a transfer medium 600 and a UV curable resin.

  Next, a UV curable resin having a film thickness of 1 μm is ejected from the resin ejection unit 502 of the transfer device 510 onto the surface of the transfer medium 600 by inkjet, and then the roll mold 501 is pressed against the UV curable resin on the surface of the transfer medium 600. In this state, a pattern was formed on the surface of the transfer-receiving medium 600 by irradiating UV light using a high-pressure mercury lamp as the UV light source 503 to cure the UV-curable resin. At this time, the feeding speed of the medium to be transferred was 10 m / min.

  Thereafter, the line sensor camera 701 scans the dummy pattern of the transfer-receiving medium 600 on which the pattern has been formed. Even when the number of times of transfer of the roll mold 501 exceeded 20,000 times, no defect in which the pattern was peeled was detected. However, at that stage, the mass production was temporarily stopped, and when the main pattern transferred to the transfer-receiving medium 600 was observed with an optical microscope, pattern peeling was partially confirmed. Needs arise. As a result, the transfer object of the roll mold 501 after the transfer number of 10,000 times was a defective product, and the yield was reduced.

  The present invention relates to the formation of patterns using imprint technology in the manufacturing process of various products such as semiconductor devices, optical components such as optical waveguides and diffraction gratings, analysis chips related to biochemistry and chemistry, and recording media such as hard disks and DVDs. The method can be suitably used as an imprint mold used for performing the method and a method for inspecting the mold releasability of the mold.

100 Base material 101 Base material (nickel)
102 Base material (resin)
103 Base material 200 Main pattern 201 Main pattern formation area 300 Auxiliary pattern 301 Auxiliary pattern formation area 302 Part of auxiliary pattern 303 Part of auxiliary pattern 304 Auxiliary pattern Part 310: Projection 400: Imprint mold 401: Nickel electroformed mold 402: Resin mold 501: Roll mold 502: Resin discharge part 503: UV light source 510: Transfer device 600: Transfer target medium 701 Line sensor camera 702 Inspection result display

Claims (2)

A method for inspecting the releasability of an imprint mold,
A base material, a main pattern provided on the surface of the base material and having a fine structure; and a shape provided outside the main pattern formation region, having a fine structure, and being discontinuous in the feeding direction of the transfer medium. A step of producing an imprint mold having an auxiliary pattern that is
Wrapping the imprint mold around a roll, to produce a roll mold,
A step of applying an ultraviolet-curable resin on the surface of the transfer-receiving medium to form an ultraviolet-curable resin layer,
A step of ultraviolet irradiation and transferring the main pattern and the auxiliary pattern to said ultraviolet curable resin layer in a state of pressing the roll mold before Symbol ultraviolet curing resin layer,
Inspecting the releasability of the imprint mold based on the presence or absence of a defect in the dummy pattern formed by transferring the auxiliary pattern to the ultraviolet-curable resin layer. . The method according to claim 1, wherein the auxiliary pattern is a pattern in which lines and spaces extending in a direction orthogonal to the transfer direction of the transfer medium are arranged in the transfer direction of the transfer medium, or a dot-shaped pattern. 2. The mold releasability inspection method according to 1.

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