Anti-counterfeiting device using NANO structure and manufacturing method thereof

Abstract

The present invention relates to an anti-counterfeiting device and a method for manufacturing the same, and more specifically, to an anti-counterfeiting device using a nanostructure that is physically impossible to replicate and has high security, and a method for manufacturing the same. A method for manufacturing an anti-counterfeiting element according to one embodiment of the present invention comprises: a pattern transfer layer forming step of forming a pattern transfer layer on a plurality of protrusions formed on at least one portion of a substrate and transferring a plurality of protrusions corresponding to the plurality of protrusions of the substrate onto the pattern transfer layer; a separation step of separating the pattern transfer layer from the substrate; and an anti-counterfeiting element forming step of forming an anti-counterfeiting element by providing a predetermined external force to randomly deform at least some of the protrusions of the separated pattern transfer layer.

Description

Technology Field

[0001] The present invention relates to an anti-counterfeiting device and a method for manufacturing the same, and more specifically, to an anti-counterfeiting device that is physically impossible to replicate using a nanostructure and a method for manufacturing the same. Background Technology

[0002] A wide variety of counterfeit products are being distributed, including clothing, watches, and accessories, as well as electronic products and medicines. Counterfeit products have a significant economic and social impact that extends beyond individuals, causing intellectual property infringement, financial loss, health risks, and personal information leaks.

[0003] To prevent and detect counterfeit products, various types of anti-counterfeiting tags have been developed and attached to genuine products. Existing anti-counterfeiting tags include graphical barcodes, holograms, and watermarks. As these tags are manufactured through a deterministic process, they pose a high risk of replication by skilled counterfeiters.

[0004] Although anti-counterfeiting tags utilizing the optical and electrical specificities of nanomaterials have been proposed to prevent duplication, they face economic disadvantages and practical limitations for actual industrial application due to high manufacturing costs and the requirement for complex read-out processes.

[0005] Considering these issues, the need for unbreakable anti-counterfeiting tags is emerging. Consequently, physical unclonable functions (PUFs) and physically unclonable devices have begun to gain prominence as next-generation security technologies.

[0006] A typical PUF utilizes a random variation formed by a non-deterministic fabrication process as an anti-counterfeiting tag. When an external stimulus is applied to the PUF tag (challenge process), a unique response is obtained (response process), and the challenge-response pair (hereinafter referred to as 'CRP') is stored in a database. Subsequently, authentication is performed by applying a challenge to the PUF tag and comparing the output response with the database.

[0007] Among the various types of PUFs, there is the optical PUF. Optical PUFs utilize light stimuli applied to the PUF tag and the resulting random patterns as CRPs. Optical PUFs have the advantages of high randomness and not requiring electricity, and can be used in a wide range of product categories.

[0008] Conventional optical PUFs utilized metallic nanomaterials randomly coated via a wet chemical process as tags. However, the wet chemical process is not suitable for mass production, and market competitiveness is low due to the high cost of nanomaterials. Furthermore, even when nanomaterials are used, there are limitations in encoding capacity because the spacing between nanomaterials is not at the nanoscale.

[0009] The encoding performance of an optical PUF is determined by the number of pixels in the response and the number of output cases per pixel. If the spacing between nanomaterials becomes wider, the pixel size increases; consequently, the number of pixels decreases for the same PUF tag size, leading to a decrease in encoding performance.

[0010] Recently, research has been conducted to increase the number of output possibilities per pixel in order to enhance encoding performance. Specifically, encoding performance has been improved by increasing the number of outputs per pixel using methods such as fluorescent dyes and Raman spectra. However, this approach lacks market competitiveness because it requires complex optical equipment.

[0011] Furthermore, studies have proposed enhancing encoding performance by adding another CRP via electrical signals rather than optical stimulation, but a complex readout process is still required. Since various products are distributed through complex supply chains and the risk of counterfeiting exists at every stage, an economical and efficient readout method is necessary. The problem to be solved

[0012] The problem to be solved by the present invention is to provide an anti-counterfeiting device using a nanostructure that is physically impossible to replicate, and a method for manufacturing the same.

[0013] In addition, the invention provides an anti-counterfeiting device using a nanostructure that offers high security through enhanced encoding performance, and a method for manufacturing the same.

[0014] In addition, the invention provides an anti-counterfeiting device using a nanostructure capable of mass production and a method for manufacturing the same.

[0015] In addition, the invention provides an anti-counterfeiting device using a nanostructure having a low production cost and a method for manufacturing the same.

[0016] In addition, the invention provides an anti-counterfeiting element that can be read using only a simple optical device, and a method for manufacturing the same. means of solving the problem

[0017] A method for manufacturing an anti-counterfeiting element according to one embodiment of the present invention comprises: a pattern transfer layer forming step of forming a pattern transfer layer on a plurality of protrusions formed on at least one portion of a substrate and transferring a plurality of protrusions corresponding to the plurality of protrusions of the substrate onto the pattern transfer layer; a separation step of separating the pattern transfer layer from the substrate; and an anti-counterfeiting element forming step of forming an anti-counterfeiting element by providing a predetermined external force to randomly deform at least some of the protrusions of the separated pattern transfer layer.

[0018] An anti-counterfeiting element according to another embodiment of the present invention comprises: a base portion; and a plurality of protrusions protruding on one surface of the base portion and randomly deformed, wherein each of the plurality of protrusions has a shape extending in one direction, and at least two protrusions adjacent to each other among the plurality of protrusions have at least one part randomly attached to each other.

[0019] A method for reading an anti-counterfeiting element according to another embodiment of the present invention comprises: a registration step in which an original image of a plurality of protrusions of the anti-counterfeiting element captured through a camera is registered in a database; a transmission step in which an image to be verified, captured through a camera of an anti-counterfeiting element attached to a product whose authenticity has not been verified, is received by an input / output device and transmitted to the database; a reading result output step in which the original image and the image to be verified are compared in the database to determine authenticity and output a reading result; and a providing step in which the database provides the reading result to the input / output device. Effects of the invention

[0020] Using the anti-counterfeiting element and the method for manufacturing the same according to an embodiment of the present invention has the advantage of being physically impossible to duplicate.

[0021] In addition, it offers the advantage of high security through enhanced encoding performance.

[0022] In addition, there is the advantage of being able to mass-produce.

[0023] In addition, it has the advantage of low production unit costs.

[0024] In addition, there is an advantage in that reading is possible using only simple optical devices, without utilizing expensive and complex optical devices. Brief explanation of the drawing

[0025] FIGS. 1 to 9 are drawings for sequentially explaining a method for manufacturing an anti-counterfeiting device using a nanostructure according to one embodiment of the present invention. FIGS. 10 to 12 are scanning electron microscope images of anti-counterfeiting devices manufactured according to the manufacturing method of the anti-counterfeiting device shown in FIGS. 1 to 9. FIG. 13 is a graph showing the degree of integration of the protrusion (310) depending on the degree of compressive strain applied to the protrusion (310) of the pattern transfer layer (300) through bending by the external force providing device (400) shown in FIG. 6. Figure 14 is an optical image of deformed nanostructures according to various radii of curvature (7.5 mm, 10 mm, 20 mm, 40 mm) in the graph of Figure 13. FIG. 15 is a series of optical images over time of an anti-counterfeiting device actually manufactured using the manufacturing method of FIG. 1 to 9. FIG. 16 is a drawing for explaining a method of reading an anti-counterfeiting element using an anti-counterfeiting element manufactured through the manufacturing method of the anti-counterfeiting element of FIG. 1 to 9. FIG. 17 is a diagram illustrating an example of an authentication algorithm that can be used in the reading method of the anti-counterfeiting element shown in FIG. 16. Specific details for implementing the invention

[0026] Hereinafter, a detailed description of preferred embodiments of the present invention is given with reference to the accompanying drawings. It should be noted that reference numerals and identical components in the drawings are indicated by the same reference numerals whenever possible, even if they are shown in different drawings. For reference, in describing the present invention, detailed descriptions of related known functions or configurations are omitted if it is determined that such detailed descriptions may unnecessarily obscure the essence of the invention.

[0027] Hereinafter, a method for manufacturing an anti-counterfeiting tag according to one embodiment of the present invention and an anti-counterfeiting tag manufactured by said method will be described in detail with reference to the attached drawings.

[0028] FIGS. 1 to 9 are drawings for sequentially explaining a method for manufacturing an anti-counterfeiting device using a nanostructure according to one embodiment of the present invention.

[0029] Referring to FIG. 1, a nanostructure protrusion (110) is formed on a substrate (100). The substrate (100) may be a silicon wafer. The protrusion (110) may have a shape that protrudes upward from one side of the substrate (100) and extends along one direction (X) parallel to said side.

[0030] The protrusion (110) may have a first width (w1) of nano size. The first width (w1) may be constant from the bottom to the top of the protrusion (110), or the bottom side may be larger than the top side.

[0031] The protrusions (110) may be arranged in multiple numbers along another direction (Y) on one surface of the substrate (100). Here, the other direction (Y) may be a direction perpendicular to the direction (X). The multiple protrusions (110) may be arranged at a certain distance from each other.

[0032] Next, referring to FIG. 2, a substrate (100) having a plurality of protrusions (110) shown in FIG. 1 is used to form an oxidized protrusion (110') using a wet oxidation process. The oxidized protrusion (110') may have a second width (w2) that is relatively larger than the first width (w1) of the protrusion (110).

[0033] Next, referring to FIG. 3, a photolithography process is performed using a photoresist (200). The photolithography process can be performed by forming the photoresist (200) on a portion of the oxidized substrate (100'). The photoresist (200) may be, for example, NR-9.

[0034] An area on a plurality of oxidized protrusions (110') that is not covered by photoresist (200) is defined as an anti-counterfeiting area. The anti-counterfeiting area may be the size of the anti-counterfeiting element according to an embodiment of the present invention. The anti-counterfeiting area where photoresist (200) is not formed may vary depending on the size or shape of the anti-counterfeiting element.

[0035] Meanwhile, although not illustrated in a separate drawing, as another method of forming an anti-counterfeiting area, unlike the method described above, a photoresist may be formed in the anti-counterfeiting area, and other areas not covered by the photoresist may be distinguished through an etching process. Additionally, as yet another method of forming an anti-counterfeiting area, a plurality of protrusions (110) may be formed only on a specific part of the upper surface of the substrate (100) rather than on the entire surface of the substrate (100) without using photoresist. In this case, a part of the substrate (100) where the plurality of protrusions (110) are formed becomes the anti-counterfeiting area.

[0036] Next, referring to FIG. 4, a pattern transfer layer (300) is formed on the anti-counterfeiting region of a plurality of oxidized protrusions (110') and on the photoresist (200). Here, the pattern transfer layer (300) may be composed of, for example, PDMS (Polydimethylsiloxane), but is not limited thereto.

[0037] The pattern transfer layer (300) can be formed by pouring liquid PDMS onto the anti-counterfeiting area of ​​the oxidized protrusions (110') and the photoresist (200) and baking it.

[0038] Next, when the baked pattern transfer layer (300) shown in FIG. 4 is flipped over after being separated from the oxidized substrate (100') and the photoresist (200), the appearance shown in FIG. 5 can be observed. As shown in FIG. 5, the pattern transfer layer (300) includes a plurality of protrusions (310). Each protrusion (310) has a third width (w3), and two adjacent protrusions (310) have a gap corresponding to a second width (w2). The second width (w2) of the oxidized protrusion (110') of the substrate (100') shown in FIG. 2 becomes the gap between two adjacent protrusions (310) of the pattern transfer layer (300).

[0039] Next, referring to FIG. 6, an external force is applied to a pattern transfer layer (300) having a plurality of protrusions (310) so that some of the protrusions among the plurality of protrusions (310) randomly stick together. To do this, the pattern transfer layer (300) having a plurality of protrusions (310) shown in FIG. 5 can be flipped over and provided to an external force providing device (400).

[0040] The external force providing device (400) is a device configured to apply an external force to the pattern transfer layer (300) so that protrusions, which are nanostructures of a part of the pattern transfer layer (300), are randomly attached to each other and deformed. For example, the external force providing device (400) may include a bending surface (410) that directly applies an external force to the pattern transfer layer (300).

[0041] When a pattern transfer layer (300) is placed on a bending surface (410) such that a plurality of protrusions (310) face the bending surface (410), as shown in FIG. 7, two or more protrusions adjacent to each other among the plurality of protrusions (310) are randomly attached to each other to form deformed protrusions (310'). A pattern transfer layer (300) having randomly deformed protrusions (310') can be used as an anti-counterfeiting element.

[0042] The anti-counterfeiting element illustrated in FIG. 7 includes a base layer (330) and a plurality of modified protrusions (310') disposed on the base layer (330). Each protrusion (310') has a predetermined width, and the distance between two adjacent protrusions (310') is equal to the second width (w2) of the oxidized protrusion (110') of the substrate (100') illustrated in FIG. 2. The plurality of modified protrusions (310') may include two randomly adjacent protrusions (310') that are completely attached to each other, or part(s) of two randomly adjacent protrusions (310) that are attached to each other.

[0043] As illustrated in FIG. 8, a thin film (500) can be coated on a pattern transfer layer (300) having additionally deformed protrusions (310'). By forming the thin film (500) on the deformed protrusions (310'), there is an advantage that the structure of the protrusions (310'), which have been deformed once, is not deformed again by other external forces. Here, the thin film (500) may be made of a metal or non-metal material. In addition, the thin film (500) may have a thickness of nano-units or less.

[0044] As shown in FIG. 9, a passivation layer (600) can additionally be formed on the thin film (500). The passivation layer (600) may be composed of PDMS.

[0045] The method for manufacturing the anti-counterfeiting device illustrated in FIGS. 1 to 9 has the advantage of enabling mass production through an 8-inch large-area process using MEMS technology. Furthermore, economic efficiency can be enhanced by using PDMS, which is a relatively inexpensive material compared to conventional nanomaterials. Additionally, by utilizing nanostructures instead of nanomaterials, high complexity can be achieved as protrusions, which are random nano-patterns at nano-intervals, exist. Moreover, no additional optical or electrical devices are required for manufacturing. Furthermore, the manufactured anti-counterfeiting device can be read using a simple optical microscope.

[0046] FIGS. 10 to 12 are SEM images of anti-counterfeiting devices manufactured according to the manufacturing method of the anti-counterfeiting device shown in FIGS. 1 to 9.

[0047] FIG. 10 is SEM images of an oxidized substrate (100') having oxidized protrusions (110') as shown in FIG. 2, FIG. 11 is SEM images of a pattern transfer layer (300) having a plurality of protrusions (310) as shown in FIG. 5, and FIG. 12 is SEM images of a pattern transfer layer (300) having deformed protrusions (310') as shown in FIG. 7.

[0048] In FIG. 10 (a) to (c), each protrusion (110') made of silicon oxide (SiO2) has a pitch of 1200 nm, a width of 350 nm, and a height of 550 nm. An oxidized wafer having a plurality of protrusions (110') becomes a master template.

[0049] In Figures 11 (d) to (f), protrusions (310) in the shape of protruding from the PDMS transferred from the master template can be seen.

[0050] In (g) to (i) of FIG. 12, it can be seen that a predetermined external force by an external force providing device is applied to a PDMS having a plurality of protrusions (310), thereby forming randomly deformed protrusions (310'). The deformed protrusions (310') may include two randomly adjacent protrusions (310') that are completely attached to each other, or parts(s) of two randomly adjacent protrusions (310) that are attached to each other. Due to the random arrangement of the deformed protrusions (310') and the length of each deformed protrusion (310'), it can be used as an anti-counterfeiting device with high complexity, such as an anti-counterfeiting tag.

[0051] FIG. 13 is a graph showing the degree of line integration of a protrusion (310) depending on the degree of compressive strain applied to a protrusion (310) of a pattern transfer layer (300) through bending by an external force providing device (400) illustrated in FIG. 6, and FIG. 14 is an optical image of the deformed protrusions according to various radii of curvature (7.5 mm, 10 mm, 20 mm, 40 mm) in the graph of FIG. 13.

[0052] The graph shown in FIG. 13 is a graph when the thickness of the PDMS used as the transfer pattern layer (300) shown in FIG. 7 is 3 mm. Referring to FIG. 13, it can be seen that when the radius of curvature of the bending surface (410) shown in FIG. 6 is less than 20 mm, the line integration ratio of the multiple protrusions (310) becomes greater than 0. Conversely, when the radius of curvature of the bending surface (410) is 20 mm or more, the line integration ratio becomes 0.

[0053] Referring to Fig. 14, it can be seen that when the radius of curvature is smaller than 20 mm, randomly deformed protrusions are formed.

[0054] FIG. 15 is a series of optical images over time of an anti-counterfeiting device actually manufactured using the manufacturing method of FIG. 1 to 9.

[0055] As shown in FIG. 15, since the deformed protrusions (310') are fixed by coating a thin film (500) of metal material in FIG. 8, it can be confirmed that the deformed nanostructures maintain their shape even after several days.

[0056] As illustrated in FIGS. 13 to 15, when the compressive strain of the pattern transfer layer (300) increases, greater compressive stress is applied to the protrusions, which are a plurality of nanostructures, thereby increasing the degree of integration of the deformed protrusions. Sufficient stress required for contact and nanostructure integration within the plurality of protrusions occurs after a certain amount of deformation is applied. Once the integration of the nanostructures occurs, it is maintained over time by the coating of a thin film made of metal material.

[0058] FIG. 16 is a drawing for explaining a method of reading an anti-counterfeiting element using an anti-counterfeiting element manufactured through the manufacturing method of the anti-counterfeiting element of FIG. 1 to 9.

[0059] Referring to FIG. 16, the anti-counterfeiting element (1000) manufactured through the manufacturing method of FIG. 1 to 9 is produced at the factory (11) of a sales company (Vendor, 10), attached or mounted on a product (15) to be protected, and then sold. Here, before the anti-counterfeiting element (1000) is attached or mounted on the product (15), the sales company (10) stores original image(s) captured through a camera (e.g., a CCD camera) of the modified protrusions (310') of the anti-counterfeiting element (1000), as shown in FIG. 7 or FIG. 12, in a database (17).

[0060] Later, a customer (Customer, 20) who has purchased or intends to purchase the product (15) can verify the authenticity of the product (15) that they have purchased or intend to purchase. Verification of authenticity may include the steps of shining a light source (30) on an anti-counterfeiting element (1000) attached to a product (15), an optical device (optical microscope, 40) photographing the anti-counterfeiting element (1000), an input / output device (50) receiving an image of the anti-counterfeiting element (1000) (hereinafter referred to as "image to be read") from the optical device (40), the input / output device (50) transmitting the received image to be read to a database (17), the database (17) outputting the authenticity (genuine or fake) by comparing the image to be read with the stored original images using a predetermined authentication algorithm, and the input / output device (50) receiving the authenticity from the database (17) and displaying it on a display unit such as a monitor.

[0061] The process of determining the authenticity of such products (15) can be performed not only at the customer (20) but also throughout the supply chain, and since the reading can be done through a simple optical device (40) and a simple input / output device (50) equipped with a communication unit, a display unit and a control unit that controls them, the economic burden for reading can be reduced.

[0062] FIG. 17 is a diagram illustrating an example of an authentication algorithm that can be used in the reading method of the anti-counterfeiting element shown in FIG. 16.

[0063] Referring to FIG. 17, the database (17) of FIG. 16 can perform image processing on the original images of the anti-counterfeiting element attached to the genuine product. Image processing can convert the original images into grayscale images to remove changes due to light intensity, or extract the main feature portions of the deformed protrusions from the original images of the anti-counterfeiting element.

[0064] In order to recognize and compare anti-counterfeiting elements regardless of rotation or scaling of the original image in the database (17) of FIG. 16, the database (17) may use a scale-invariant feature transformation (SIFT) algorithm.

[0065] The SIFT algorithm identifies features of the original image and the image to be read, and compares features between the two images. The similarity between the two images is determined by the Correct match ratio (CMR), which is the ratio of matching features between the images, as defined in <Equation 1> below.

[0066]

[0067] In the above <Mathematical Formula 1>, a higher CMR value indicates a higher degree of similarity between images.

[0068] In the authentication system of FIGS. 16 and 17, if the CMR is 0.1 (10%) or higher, it can be considered genuine. Using the authentication algorithm, the inventors were able to confirm authenticity without error by obtaining a CMR of 34.3% even under rotation and other lighting conditions. Conversely, in the case of an unregistered counterfeit, the CMR value was close to 0, allowing for effective identification of the counterfeit.

[0069] The authentication algorithm illustrated in FIGS. 16 and 17 is robust against factors such as brightness, background noise, magnification, and rotation, and can verify anti-counterfeiting elements even with low computing power, making it suitable for deployment to end users and various supply chains.

[0070] Although embodiments of the present invention have been described above with reference to the attached drawings, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims. Explanation of the symbols

[0071] 100: Substrate 110: Protrusion 100': Oxidized substrate 110': Oxidized protrusion 200: Photoresist 300: Pattern transfer layer 310: Protrusion 310': Modified protrusion 400: External force supply device 500: Thin film 600: Passivation layer

Claims

Claim 1 A method for manufacturing an anti-counterfeiting device, comprising: a step of setting an anti-counterfeiting area, wherein a photoresist is formed on at least one portion of a plurality of protrusions formed on at least one portion of a substrate, and an anti-counterfeiting area is set on the remaining portion where the photoresist is not formed; a step of forming a pattern transfer layer composed of PDMS (Polydimethylsiloxane) on a plurality of protrusions within the anti-counterfeiting area, wherein a plurality of protrusions corresponding to the plurality of protrusions within the anti-counterfeiting area are transferred to the pattern transfer layer; a separation step, wherein the pattern transfer layer is separated from the substrate; and a step of forming an anti-counterfeiting device, wherein a predetermined external force is applied to at least some of the protrusions of the separated pattern transfer layer so as to randomly deform the anti-counterfeiting device. Claim 2 A method for manufacturing an anti-counterfeiting device according to claim 1, further comprising an oxidation step of oxidizing a plurality of protrusions of the substrate prior to the step of forming the pattern transfer layer. Claim 3 delete Claim 4 A method for manufacturing an anti-counterfeiting element, further comprising a thin film forming step of forming a thin film on a plurality of modified protrusions of the anti-counterfeiting element in claim 1. Claim 5 A method for manufacturing an anti-counterfeiting device, further comprising a passivation layer forming step of forming a passivation layer on the thin film in claim 4. Claim 6 A method for manufacturing an anti-counterfeiting device according to claim 5, wherein the passivation layer is PDMS. Claim 7 A method for manufacturing an anti-counterfeiting element according to claim 1, wherein, in the step of forming the anti-counterfeiting element, at least one part of at least two of the protrusions among the portions are randomly attached to each other by the external force. Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete

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