Multi-layered hybrid security label

Abstract

The invention relates to the use of lithography and the multi-layered hybrid security label, which can be produced in harmony with the electronic industry, and the production method of this label.

Description

[0001] MULTI-LAYERED HYBRID SECURITY LABEL

[0002] Technical Field

[0003] The present invention relates to a multi-layered hybrid security label using lithography, which can be produced in harmony with the electronics industry, and a method of production of this label.

[0004] State of the Art

[0005] Today, it is an indisputable fact that the internet is everywhere in our lives with the development of digitalization and technology in every field. Where there are so many digital connections, the protection of security, personal information, material, and spiritual values is a huge problem. In addition to the software security measures taken for this purpose, it requires hardware security measures to be taken for each electronic device used.

[0006] Considering the security application areas, electronic devices in which personal security is very critical cannot be ignored. While the existence of software security measures in this field has caused controversy about reliability, it is very difficult to say that there has been progress in hardware. Especially when it comes to electronic circuit production and integrated industry, a hardware-specific security label production that can work in harmony with the lithography methods that come to mind and is produced during production appears to be a mandatory step in this field.

[0007] For each electronic device that can cause the biggest security weaknesses in our lives, we face the necessity of a fingerprint-like label that belongs to the human being and cannot be reproduced. However, difficulties in implementing existing approaches are inevitable. For example, label production is still a major challenge with the use of printing, dipping or solvent-based materials with the electronic integrated industry. Label production is almost impossible with the use of existing approaches and processes on integrated circuits produced with methods such as lithography method, especially due to the great progress of the electronic industry and the development of technology. In short, given today's technological progress, there is no procedure for producing a security label that can work in harmony with the production processes.

[0008] Apart from this, considering the current usage areas, in the studies on security labels, mostly deterministic processes and different nanomaterials are based on geometric shapes or barcode forms. However, due to their inherent nature, these security tags are susceptible to counterfeiting.

[0009] Labels based on easily accessible methods such as printing and facilitating the production of nanomaterials with the development of technology are not difficult to imitate by manufacturers of counterfeit products. On the other hand, studies involving security tags based on physically unclonable functions are limited to a few materials and applications.

[0010] The limited material used in labeling not only restricts the authentication mechanisms, but also reduces the encoding capacity. There is often a need for a limited number of surfacematerial varieties that have been treated with specific modifications to interact with specific chemical and mechanical conditions for the creation of physically unclonable functions (PUFs). Again, there are difficulties in the integration of PUFs produced with approaches based on the distribution of nanomaterials into a certain polymer matrix.

[0011] Another problem identified in prior arts is the inability of PUF structures to maintain their chemical and physical integrity against environmental influences. This is due to the application of micro-nano-sized functional materials that will serve as the PUF structure where random patterns are formed, or these structures cannot be applied directly on the product-object in polymeric matrices and / or through labels. The fact that the materials that make up both the support material and the PUF structures do not have sufficient durability, especially in humidity, temperature, and chemical environments, may cause the original keys removed from these structures to change over time, thus bringing along problems in terms of long-term and reuse. Therefore, it is of great importance to develop new generation PUF production systems and PUF materials that can be applied directly to the relevant application object and are highly resistant to environmental effects. Innovative and efficient fabrication methods and materials are needed to develop new highly durable PUF platforms suitable for direct integration. These PUF platforms should be based on stochastic processes and suitable for producing random patterns without the need for an easy and complex infrastructure. These platforms should be able to be integrated with deterministic barcoding processes when necessary.

[0012] The first study on functions that cannot be physically cloned (Science 2002, 297, 2026-2030) was carried out at Massachusetts Institute of Technology of America, inspired by mathematical one-way functions. In this study, the concept of PUF has been introduced based on the scattering of particles randomly dispersed within a polymeric matrix under laser illumination . In recent studies, PUF production has been carried out with the approaches of deposition of colloidal nanomaterials at low concentrations (Adv Funct Mater 2016, 26, 1315- 1321), folding of plasmonic gels (ACS Appl Mater Inter 2016, 8, 4031-4041), incorporation of lanthanide-doped zeolites in polymer films with luminescent properties (Science advances 2018, 4 (1), el701384), self-assembly of carbon nanotubes (Nat Nanotechnol 2016, 11, 559) and chemical vapor deposition of two-dimensional materials (ACS Nano 2017, 11 (12), 12772-12779).

[0013] It is related to the direct formation of dendritic metal structures that cannot be cloned randomly in US10223567B2 by electrolysis on the surface with solid or liquid electrolytes. These dendritic metallic structures with random shape orientation and size can form PUF keys with integrated circuits.

[0014] US 10056905 describes devices that cannot be physically cloned based on nanomaterials. Nanomaterials are randomly positioned in the PUF layer placed under a general electrode. Signals from these randomly distributed electrodes can be read as PUF keys with an integrated circuit.

[0015] W02010076733A1 relates to a semiconductor device developed for use in the manufacture of PUF. There is a physical structure inside the device for the purpose of PUF. This structure includes a dielectric layer containing lead zinc titanate and silicon deposited thereon. The dielectric layer has a rough surface. By depositing a conductive layer on this rough surface, a resistor with random values can be produced. The patent document numbered CN103124979A is based on trapping the particles on a surface with deterministically determined roughness and using the random patterns obtained in the production of PUF.

[0016] With patent document US20100224686A1, there is a method and device development for the generation of random codes. This patent uses a mechanical device with holes.

[0017] As a result of the above information and research, no technical solution related to the hybrid security label using lithography method has been found.

[0018] Objects and Brief Description of the Invention

[0019] The present invention relates to a hybrid security label developed using the lithography method, which has its own unique, unclonable structure such as fingerprints for electronic devices with flat surfaces such as processors and antennas, and the production method of this security label, in order to bring solutions to the above-mentioned technical problems and to bring new advantages to the relevant technical field.

[0020] The main object of the invention is to provide devices with a unique security tag, similar to a fingerprint, creating an unclonable and unique identity for each device.

[0021] Since the production of the proposed security labels is based on lithography methods, a label that can be produced in harmony with the electronic industry is aimed.

[0022] Another object of the invention is to ensure that PUFs are patterned in desired geometries.

[0023] It is a great advantage that the security labels obtained in the present invention are obtained by the lithography method. Especially considering the electronics industry, lithography methods are the most common method encountered during the production phase. This allows for the simultaneous production of security labels without the need for any additional processing during the fabrication of electronic integrated circuits. In addition, it is a great advantage of the invention that deterministic and stochastic-based working security processes can be presented on a single label and have different options for production. Some other features that make the invention different in the state of the art are as follows:

[0024] • The use of randomly generated structures by electro spraying method as physically unclonable security labelss,

[0025] • Application of lithography techniques for the production of multi-layered security label,

[0026] • Suggestion of a security label that is compatible with integrated circuit fabrication processes, allowing one-to-one compability during the manufacturing process.

[0027] Another advantage of the invention is that it is possible to create the inner layer structure from multi-layered structures by selecting many methods.

[0028] The invention has the potential to be used with all electronic devices in general. Because every electronic device contains a fundamental processor or a basic integrated circuit. Since this situation brings with it the use of lithography, it has potential in terms of this application.

[0029] Besides the security labels proposed in the present invention can offer a very high level of security, it is possible to make a hardware encryption with a label of an unclonable nature for the security of the motherboard or processor in the computer production of each electronic device, for example. With the sampling of the area of use electronically, valuable paintings, works of art have the potential to be used for every application that requires high security. If lithography compatibility is brought to the forefront, it has a wide range of potential for use for the hardware security of electronic equipment such as phones and computers.

[0030] Definitions of Figures Describing the Invention

[0031] The figures and related descriptions used for a better description of the developed invention are as follows.

[0032] Figure 1: Particle size control: Particles of different size after electro spraying of resist solutions of different viscosity and soft baking step at 95 °C for the obtained structures. Figure la: Particles obtained by direct e-spraying of a commercially available resist solution named SU8-2 (having a viscosity of 45cSt).

[0033] Figure lb: Particles obtained by direct e-spraying of a commercially available resist solution named SU8-10 (having a viscosity of 1050 cSt).

[0034] Figure 1c: Particles obtained by e-spraying diluted resist at a ratio of 3:1 by volume with the use of cyclopentanone for SU8-2 resist.

[0035] Figure Id: Particles obtained by e-spraying diluted resist at a ratio of 3:1 by volume with the use of cyclopentanone for SU8-10 resist.

[0036] Figure 2: Schematic representation of the process steps

[0037] Figure 2a: Schematic illustration for electro -spraying

[0038] Figure 2b: Schematic representation for lithography

[0039] Figure 3: PUF structures patterned in different sizes by maskless lithography; square frames with an edge length of 200-400-600 microns and resist particles randomly distributed within them.

[0040] Figure 3a: Square structure with 200-micron edge length

[0041] Figure 3b: 400-micron edge-length square structure

[0042] Figure 3c: 600-micron edge-length square structure

[0043] Figure 4: Patterning of the resist particles deposited on the surface with electrospray in the form of a QR code by photolithography.

[0044] Figure 4a: QR code structure forming the outer layer Figure 4b: A larger magnification (50x) image of a region selected over the QR code

[0045] Figure 4c: Conversion of a close-up image into a black and white format for clear particle / gap determination

[0046] Figure 4d: Transformation of the black and white image into a 256-bit barcode (inner layer)

[0047] Figure 5: Images obtained for stability tests; including images taken from the same point before and after each stability test.

[0048] Figure 5a: Untreated

[0049] Figure 5b: After 450°C temperature

[0050] Figure 5c: After washing with ethanol

[0051] Figure 5d: After washing with acetone

[0052] Figure 5e: After washing with DMF

[0053] Figure 5f: After washing with propanol

[0054] Figure 5g: After washing with chloroform

[0055] Figure 5h: After washing with chlorobenzene

[0056] Figure 5i: After washing with cyclopentanone

[0057] Description of the References

[0058] 1 Mask

[0059] 2 Sample 3 UV Lamp

[0060] Detailed Description of the Invention

[0061] This explanation is only for a better understanding of the subject and the security label, and the production method of this label are explained in detail in a way that does not have any limiting effect.

[0062] On the basis of the invention, a security label consisting of inner and outer layers with deterministic and stochastic working principle is obtained. The invention has a multi-layered unclonable label structure.

[0063] The invention is about the use of randomness to be obtained on the surface with the resist solution used for lithography and creating multi-layered security labels from an outer label layer such as a barcode, QR code, text or shape patterned with lithography as a hybrid security label.

[0064] The invention provides a system and method for creating a physically unclonable function by accumulating resist solutions on the surface in a way that generates randomness (e.g., through electrospraying).

[0065] The invention is based on the deposition of resist solutions on the surface (Here, electro spraying process is used for this purpose in the production stage for electronic integration) and also on the methods of patterning the resist structures deposited on the surface with different lithography methods.

[0066] In general, the process steps of the production method of the security label carried out with the invention are as follows:

[0067] First of all, to create the physically unclonable structure forming the inner layer mentioned as the two-layer system, a resist coating is applied using a coating method that ensures randomness. For this purpose, there is an electrospray method or a resist coating to be made with different polymers (such as polystyrene brush coating) to form dewet structures (crystal structures). Here, it is desired to produce PUF (Physical Unclonable Function) stochastic labels with the basis of coating the resist in random locations, geometries, colors on the surface and image processing processes.

[0068] As a second step, there is the process of shaping the coated resist structure with lithography. Alternatively, photolithography, laser printing lithography and electron beam lithography methods can be selected for this situation. As a working principle, when the polymer-based solution, which is called the resist and coated on the surface, encounters light in the UV region (the same is the case for the Laser and Electron beam), thanks to the photoacid generators, the monomers of the resist are activated (for the negative tone resist), the parts that see the light in this way are cross-linked on the surface, while the part that does not see the light maintains its initial state. The development step is carried out with the developer solution included in the lithography step, which may differ for each resist (GBL for the SU8 resist mentioned above). This step is performed by immersing the lithography-treated sample (2) in a solution called developer and washing and rinsing it.

[0069] As a result, a label is produced with a resist layer that includes randomness (position, geometry, color) and when viewed with a larger objective, the random characteristics of the resist coating create a unique pattern.

[0070] When shaping the surface using lithography, if the desired pattern is selected as a deterministic barcode shape, then, in a general framework a barcode will be observed, which is referred to as the outer layer in the invention.

[0071] When viewed with larger objectives and closer focus, it becomes possible to obtain a stochastic label in the form of an FKF structure. As a result, a two-layer security tag, an encryption tag, is achieved.

[0072] The invention differs from the known state of the art by incorporating a coating method (such as electrospray or crystallization), a lithography step (e.g., photolithography, laser print lithography, electron-beam lithography) and image processing, matching and verification algorithms (MATLAB interface). While the deterministic security label (for example, the square code structure), which is the outer layer in the structure that requires multi-layered matching, serves as the first matching layer, the structure of the resist on the surface, which contains random location, random shape or random color, forms the other security layer stochastically or in other words, with a randomness that cannot be repeated. Basically, the first matching layer is a simple barcode, such as a QR code structure.

[0073] For the stochastic -based structure that acts as an internal security layer; the source of randomness used determines the method to be used. The source of randomness, which is the basis of PUF structures, was created with this step.

[0074] The structure to be expressed by the outer layer refers to the shape of the resist structure on the surface, regardless of how the resist layer is transferred to the surface. For example, for the example given in Figure 4, this outer layer is a QR code structure. For this reason, when using the term of multi-layered matching, scanning the QR code is a phenomenon that forms the outer layer. Secondly, it is related to the deposition of the solution, which is called a resist and can be shaped by lithography, at random locations on the surface, not as a normal film. If we need to exemplify over Figure 4, when creating the QR code structure, instead of using a film-shaped resist structure to accumulate the resist layer on the surface as a process step before forming, the resist coating on the surface was preferred with the electrospray process. The object here is to obtain particles in nano-micro sizes at random locations on the surface. An example of this situation is the figure in Figure 4b. In the case of a normal film coating, a homogeneous film image, not a particle, would be obtained on the surface, but the formation of resist particles at random locations was observed by the selected process step (electrospraying). In this case, for example, with the larger objective for figure 4, there is a chance to create a 2nd layer when the QR is focused on a region of the code and an image is received. In order to obtain this layer, images taken with a larger objective (Figure 4b) can first be translated into a black and white form (Figure 4c) and then into a barcode with the desired bit capacity (Figure 4d) and a library can be created with these barcodes. In addition, a library that requires direct image matching can be created without barcode dialing (with Figure 4b). The second layer of security or the inner layer can be created in this way. For this purpose, during the application, the image to be taken from a certain region from the surface and the library can be searched and matching is provided. This process can be performed in a simple way using MATLAB image processing and image analysis algorithms. A security label principle is ensured by the matching status and whether there is a similar shape in the library.

[0075] The presence of resist in random locations makes it possible to obtain a random and unrepeatable structure. A method that can be selected for this purpose is to produce structures that will act as physically unclonable functions (PUF) randomly positioned on surfaces by using electrohydrodynamic instabilities acting on solutions prepared from commercial resistbased materials by electro spraying method on the surface.

[0076] In order to use the randomness of different shapes, a process can be selected to obtain structures that can show random distribution at different locations on the surface or that are formed by a sub-process made on the surface with de-wetting instability.

[0077] As another approach, by heating the deposited resist in the form of a spray on the surface at high temperatures, it can be used as an PUF structure, which is not possible to obtain different structures in shape and the color differences that will occur in the resist structure. After the inner layer is created, lithography processes are used to create an outer layer that can serve as a deterministic security label for the structures obtained on the surface such as barcode, square code, shape, text. This can be used as the second security layer to be formed by enclosing the PUF structure in the first layer in a suitable outer frame.

[0078] The invention provides the fabrication method of a unclonable hybrid security label using the lithography method.

[0079] In the method mentioned in the invention, there is a chance to choose many methods when forming the inner layer. Here, detailed information is given in the electrospray method, which can be selected by using many parameters previously mentioned for encoding purposes. For this selected method, basically, electro spraying method by preparing the resist solutions directly or at appropriate parameters (such as dilution) by exposing the electrohydrodynamic forces to the droplets and depositing them directly on the surfaces to be placed on the collector in solid form in the form of droplets-particle, ensuring that the resist accumulated at random locations on the surface by lithography / maskless lithography / nano-printing method for the purpose of a second label layer is cross-linked on the surface or in the development step specific for each resist and included in the process step, dissolving the area outside the formation of the shape in the solvent for the negative resist exposed to light / electron in the step of removing the unexposed area from the surface, dissolving the area outside the formation of the shape in the solvent, for example, with the gamma-butyrolactone (GBL) for SU8 resist, removing the resin from the surface by removing it from the surface in the desired security frames. The invention defines these production processes.

[0080] Regarding electro spraying equipment, electro spraying equipment mainly consists of four main components. The first of these components is a conductive nozzle with small openings, such as a syringe-like chamber to contain solutions and a syringe needle to be placed at the tip of this chamber.

[0081] The second component is the syringe pump or a pneumatic feeding system. It ensures a constant volume of solution from the chamber is fed to the conductive end per unit time.

[0082] The third component is a fixed metal plate or movable cylinder drum positioned at a horizontally or a specific distance opposite the nozzle, which is used as a conductive platform for deposition of formed droplet-particles.

[0083] The final basic component is the high-voltage source, which is the driving force for the E- spray process. The negative and positive outputs of the high voltage source are connected to the collector and nozzle, creating an electric field that allows the solution to be carried towards the collector spontaneously by the effect of electrostatic forces. The solution from the reservoir is fed to the nozzle by the feeding unit, in the other word to the end of the nozzle. The power supply creates an electric field between the conductive nozzle and the collector. The surface on which the physically unclonable function (function structure) is to be accumulated is placed on this collector. The electrohydrodynamic force generated by this electric field allows the solution sprayed from the nozzle to be scattered in particle form and move towards the collector. The nozzle acts as an outlet for the solution. It also enables the creation of an electric field due to its conductive structure, subjecting the solution to the electrohydrodynamic force. The spraying of the solution is entirely accomplished through electrohydrodynamic forces. Similarly, the scattered solution particles / droplets / particles are directed towards the collector by the electrohydrodynamic force. During the electrospraying process, the solution particles moving from the nozzle to the collector interact with each other due to the accumulated Coulombic charges on their outer surfaces, causing them to repel one another.

[0084] This continuous interaction results in the solution particles not following calculable and / or repeatable paths that can be expressed in precise locations. Since the movement of each particle from the nozzle to the collector depends on the cumulative effect of these particles on each other, a chaotic path occurs. As a result of the deposition of solution particles on the surface of the collector, completely irregular structures and patterns are formed. The aforementioned disorder is sufficiently random that these structures form a physically unclonable function (PUF). Through electro spraying, resist droplet-particles are are randomly positioned on surfaces over a wide area, continuously generated., These surfaces form the basis for the lithography procedures to be applied afterwards. The lithography step is also used for the formation of the outer layer. For this purpose, the use of maskless (laser printing) lithography or masked lithography method may be preferred. For this purpose, emphasis was placed on 2 methods.

[0085] The lithography method with an maskless laser lithography basically consists of 3 main components. The first is preferably a laser source with a wavelength of 375 nm, which scans the surface by carrying energy onto the surface in order to crosslink the resist or break the bonds with the surface and remove it from the surface. Wavelength can be preferred in the range of 200-400 nm. Selection can be made according to device features and intended use.

[0086] The second component is a horizontal axis with 3 (x-y-z) axis mobility that works integrated with various computer program interfaces where the substrate is placed under this laser source.

[0087] As the third component, it is the vacuum pump that will perform the vacuum environment needed in the realization of the process and provide the vacuum conditions in the closed box where the system is located from the position of the horizontal axis. In the lithography method with maskless laser, surfaces with negative resist-based random structures produced by electro spraying on them are placed on the table with holes that allow them to be pulled with vacuum in order not to be affected by mechanical movements in the system. A UV laser is focused on the surface by bringing it to the appropriate vertical distance with the surface by applying procedures that vary according to the laser lithography device used. The coordinate / CAD programs and previously designed barcode geometries are transferred to the table and the UV laser scans the desired surface regions linearly with the movement of the table and treats these regions with light at the appropriate wavelength (exposure). Resist forming PUF structures, which are treated with light in sufficient time, form chemical bonds with each other. Then, with the development process, the structures in the regions that do not see light are removed from the environment by washing the surface in a suitable solvent, while the particles in the exposed areas remain in the location where they are located since they become chemically insoluble in the relevant solvent. As a result, PUFs are patterned in desired geometries.

[0088] The method of the invention can be applied with masked lithography methods other than maskless direct laser lithography. Masks previously designed as security barcodes can be positioned on the electro sprayed surface. Because although the barcode structure is the same, the electro sprayed resist structure in it is unique for each produced sample (2). In this case, instead of masked lithography with a mask (1) design for the barcode, operations can be performed with masked lithography. In this way, instead of using lasers for hours, the use of UV light sources in seconds can provide a great advantage in terms of speed, cost, practicality and mass production.

[0089] The masked lithography system also basically consists of 3 main components. The first component is the UV light source that will allow the resist to be dosed, the UV source with a wavelength of 350 nm can transfer 13 kJ energy to the surface per second, thus ensuring a faster process. The second component consists of the plane on the horizontal axis with the vacuum pump connected 3-axis movement in which the substrate is placed. The third component is the mask (1) slot located between the UV light source and the substrate plane, designed for placing the middle mask (1), which is an integrated structure in the substrate plane. The mask slot has a vacuum connection structure and can be disassembled and attached depending on the size of the mask (1) in order to keep the mask stable. The last main component is the designed mask. Glass, ceramic, metal or plastic structures can be preferred for the design of the mask (1), which can consist of various materials. In the application of the method in masked lithography, masks (1) designed with PUF structures electro sprayed on the surface as in the prior art and mask (1) alignment device ensure that the masks are aligned at the desired position on the surface. Lithography masks are prepared with the principle that the UV light used can pass through unmasked areas and cannot pass through masked areas. The PUF structures under the light-conducting regions of the produced masks are dosed with UV light and made chemically insoluble as in the previous method. Then, with the development process applied, while the PUF structures in the areas in the mask (1) projection remain on the surface, the PUF structures in the areas in the nondosed areas are removed from the environment and the patterning of the PUFs in the desired geometries is completed. In addition, similar results can be obtained with the use of electron beam lithography. With a logic similar to the laser scanning the surface focused on the surface used in the maskless lithography method, it is possible to obtain the desired shape on the surface by bombarding an electron beam focused on the surface in this method. For this purpose, the necessity of choosing the structure accumulated on the surface as an electronsensitive material, which will create randomness, emerges as the most important point that separates the method. Apart from this, the general operation and the principle of creating a security label proceeds similarly to the other lithography steps given. Thus, it is seen that it is possible to realize the proposed process with different options in terms of production. PUF structures formed at random locations by electro spraying method are obtained by using different viscosity resist solutions directly or by preparing (such as dilution). Different resists have been electro sprayed to illustrate the inventive concept regarding the availability of PUF structures of different sizes and geometries in the use of solutions of different viscosity.

[0090] The prepared solutions are electro sprayed onto different sized substrates taped with carbon tape on a movable conductor collector (in one example, a 70 mm diameter 100 mm wide metal rotary drum) or a stationary collector (in one example, a 100 mm x 200 mm steel leva) to produce random patterns deposited spontaneously on these substrates. As electro spraying parameters, the distance of the nozzle collector is 15 cm, the solution feed rate is 0.5 to 2 ml / h (h), the applied voltage is 15 to 22 kV, and the deposition time is 10 to 30 seconds. PUF structures can be formed by electro spraying on a wide variety of substrates such as silicon, glass, metal surfaces, electronic chips and integrated circuits. Optimizations made depending on the solution (concentration of resist, solvent conductivity used, dielectric constant and volatility) and process (applied voltage, feed rate) parameters and the average singular dimensions, dimension homogeneity and characteristic shapegeometry of the PUF structures produced as a result of the soft baking step applied at certain temperatures (95°C) and in time (5 min) are checked. Following the production of random patterns that exhibit the desired characteristics, lithography is performed to transfer the pattern structure determined as barcode-like on the surface.

[0091] According to the characteristic feature (negative, positive) of the resist used after the lithography procedure, the first step of barcode formation is performed as a result of crosslinking of the resist to the surface or disconnection from the surface for the desired pattern. In exemplary embodiments, solutions of different viscosities called SU8 were used. While this process is performed for the use of maskless lithography, the scanning speed of the laser is set in the range of 0.1-1 mm / s, the width of the laser on the surface is set to 1 micron, and the step range of the laser is set to 1-2 microns. Since the parameters here determine the amount of resist that will crosslink on the surface, optimum results were determined by experimenting with different speeds and different step intervals in the studies.

[0092] As a result, the barcode / QR code structure, which exhibits the desired characteristics, can be read on the smartphone camera and the first stage of matching or label work can be carried out. In the second stage, the unique patterns created by the resist on the surface are taken for each pixel in the large pattern through an optical microscope or lens integrated into the phone camera; the images are examined by various image analyzes applied through the computer program, and the unique random structure of each PUF structure is converted into binary keys consisting of 0 and Is and these keys are converted into 256-bit binary barcode shapes.

[0093] Randomness, homogeneity and uniqueness ratio and Hamming distances are analyzed from the images of the produced patterns to reveal the potential to be used as a PUF. The application to be authentic ated-PUF structures integrated into the object or produced directly on it can be used for the authentication of that asset.

[0094] Exemplary embodiments of the invention: Exemplary Embodiment 1:

[0095] In one example of the invention, continuous PUF structures were formed on silicon substrate of cumulatively controllable morphology and size thanks to SU8 solutions of different viscosities and different electro spraying parameters applied while creating patterned areas consisting of random PUF structures. In this process, two different SU8 solutions with a viscosity of 45 cSt and 1050 cSt (stock per cent) were electro sprayed. The solutions of SU8 (a kind of epoxy-based resist solution containing a resin group) to be electro sprayed were first taken into syringes with a volume of 10 mL. The syringe was used as a conductive nozzle with a flat tip at 18g opening.

[0096] Electro spraying was carried out by depositing 10x10 mm2surfaces on silicon substrates treated with fluoroalkyl silane molecules in the gas phase through carbon tape on the metal drum located at a horizontal distance of 15 cm from the syringe tip. The solution was electro sprayed on these substrates at different solution feed rates (0.25, 0.5, 1, 1.5 and 2 mL / h) with different potential differences (15, 19 and 22 kV). These structures were subjected to a preheating process called soft baking in order to increase the adhesion of the PUF structures, which are continuously accumulated on the electro sprayed surfaces, with the surface and to ensure shape homogeneity. This process was carried out by holding the substrates containing PUF on a heating table at 95 °C for 5 minutes. The application of different electro spraying parameters followed by the soft baking process is shown in Figure 1, where cumulatively average sizes of controllable PUF structures can be obtained. The obtained structures were cross-linked under UV light with a wavelength of 365 nm and continuous PUF structures were created.

[0097] Exemplary Embodiment 2:

[0098] In another embodiment of the invention, deposition was made on silicon substrates treated with fluoroalkyl silane molecules using two different SU8 resist solutions with different viscosity (45-1050 cSt) by electro spraying. 15-22 kV was selected as the potential difference applied during electro spraying and 0.25 to 2 mE / h as the solution feed rate. The obtained PUF structures were subjected to soft baking by holding the substrates containing PUF on a hotplate at a temperature of 95°C for 5 minutes. The layer of resist particles formed at random locations on the substrate was patterned in maskless lithography in order to apply the PUF structures as the second layer in order to be able to be patterned in specific regions. The patterning process was carried out in square geometries of different sizes (200x200, 400x400, 600x600 pm2). The pattern structure in the desired geometries was realized by scanning the area on the silicon substrate of the UV laser at the coordinates entered in the CAD program. When performing the patterning, the laser was selected as full power (1 Watt), the scanning speed as 0.1 mm per second, and the laser scanning step range as 1 micron. Due to the character of the SU8 resist, the resist is cross-linked where the negative laser scans.

[0099] After the patterning process, the development process is carried out. This step is performed by immersing the resist in the SU8 developer for 45 seconds in order to remove the parts of the resist that are not exposed to scanning from the surface, and then a 30-second immersion is performed in the propanol to clean the developer solution on the surface. In Figure 2, the production steps of the patterned PUF structures are schematized. In Figure 3, SU8 PUFs patterned on square areas of different sizes are given. Non-copyable keys were extracted from PUF structures patterned in different sizes and geometries. This process takes place by taking images from the surface at different magnifications with the use of an optical microscope, examining them with various image analyzes applied through the MATLAB program, and obtaining 256-bit binary codes from random PUF structures. Figure 4 shows the extraction of the keys consisting of 0 and 1 bits obtained from a region consisting of a patterned PUF.

[0100] Exemplary Embodiment 3:

[0101] In another embodiment of the invention, the SU8 resist (with a viscosity of 45 cSt) was deposited on the silicon substrate by electrospraying and then patterned in the form of QR codes by masked lithography method. As a result of transferring the square code structure in the determined lithography mask to the surface, a 2-step authentication / security label was created. When performing electro spraying, 1 mL / h feed rate and 19 kV potential difference were used as parameters.

[0102] Electro spraying was performed on surface modified silicon substrates with fluoroalkyl silane for 30 seconds. The continuous PUF structure produced was subjected to preheating at 95°C for 5 minutes. Subsequently, barcode transfer to the surface was performed using masked lithography. For this purpose, the mask with a barcode shape on it is a glass-based structure. The barcode structure to be transferred to the surface in these masks is designed to have 25x25 square and each square has 2-micron edge length. In order to create the desired barcode structure, some squares are transparent, and some squares are opaque within the barcode area on the mask (1). Thanks to the UV light exposure reaching the surface from the transparent areas in the mask (1) when exposed to UV light, negative tone PUF structures are cross-linked on the surface, and the areas corresponding to the opaque parts of the mask (1) cannot form cross-links in the work-drop areas and are removed from the surface with the next step, the development step. Thus, a square code structure is obtained by grouping the particles obtained at random locations with electrospray. The PUF patterns in the QR code structure are readable by the phone camera or barcode reader, and this constitutes the first basic layer of security verification and security measure.

[0103] The pattern created by the PUF structures in the selected unit square regions within the QR code structure is displayed with an optical microscope, and then 256-bit unclonable security keys are extracted from each specific image region in the MATLAB program. In Figure 5, PUF structures with 2-layer security verification produced by masked (1) lithography are defined. In this example of the invention, it has been shown that solid patterns in the form of random, non-reproducible particle-droplets can be obtained by electro spraying SU8 solutions, and the usability of these patterns as PUF structures has been shown. Unique 256-bit physical security switches were obtained with electrospray PUFs.

[0104] While the barcode structure can be observed with a smartphone camera; patterns consisting of random electrospray resist structures can be viewed directly under a light microscope. Controlling the structure-dimension scale at certain levels thanks to both the barcode structure and the electro spraying process ensures that this imaging process can also be done with lenses integrated into a smartphone.

[0105] Exemplary Embodiment 4:

[0106] In another embodiment of the invention, a highly durable reusable PUF system is defined, which is produced using both maskless and masked lithography techniques under chemical effects and high temperature. The stability of the patterned PUF systems, created with appropriate electrospray parameters and lithography procedures, is tested before and after prolonged exposure to high temperatures and organic solvents. The results demonstrate the chemical resistance and stability of the PUF system under challenging conditions, ensuring its long-term viability and repeatability of PUF keys.

[0107] In one example, PUF patterns produced in the form of QR codes have yielded 256-bit codes containing PUF keys. Subsequently, the samples (2) were heated at temperatures of 300°C and 450°C for 72 hours each. After each heating step, PUF morphology was compared with its preheating state by imaging under an optical microscope. No morphologically significant change was observed in PUF structures. On the other hand, the keys extracted before heating matched the keys extracted after heating. The same processes were performed after immersion tests in organic solvents (acetone, propanol, ethanol, DCM (Dichloromethane), Toluene, Chloroform, DMF (Dimethylformamide), Chlorobenzene) for 3 hours, apart from these, the durability of SU8 resist was observed by repeating the immersion tests in cyclopentanone, which is its own solvent, and in its own developer. The pre-test and post-test images of the samples (2) prepared for each test were compared and it was confirmed that the PUF structures remained intact, and the security codes extracted from PUF were reusable even after exposure to various environmental conditions, including high temperatures and organic solvents

[0108] After each test, it was observed that the barcode structures, which serve as the first security layer, could still be read using a barcode reader. The images taken were subjected to matching via MATLAB and almost complete matching was observed with the images after the test. This situation is shown in Table 1. In addition, PUFs with high durability from the result of temperature and chemical exposure tests are shown in Figure 6. In addition, as in this application, the table below shows the formation of random colors with images taken in more detail for the same structures and that they can be used for coding in these colors. For this purpose, a high-capacity security label was obtained following the creation of RGB color codes for each pixel and digitization using color codes similar to the above exemplary application.

[0109] Table 1: Matching ratios of the image before and after each application

[0110] Based on Table 1, it was observed that there were approximately 99% of matches.

[0111] Hybrid security label:

[0112] • An outer label layer, which serves as the first matching layer, patterned with the lithography printing method to create multi-layered security labels and the use of nonrepeatable randomness obtained on the surface with the resist solution,

[0113] • It contains multiple properties created on the same surface with the electro spraying method (the density of the structure given in Figure 1 on the surface, having different geometries randomly, and making visible reflections in different colors with external factors such as heating are among the features that can be used for PUF structures) and internal security layer with multiple security layers (As stated in the upper part; the outer layer and the inner layer can be qualified as the structure) (The inner security layer is the part that forms the stochastic security foundation and the physically unclonable label structure because it is a random structure).

[0114] Hybrid security label production method with the use of lithography characterized in that it comprises the following:

[0115] • Degradation of the resist solutions into droplets by exposure to electrohydrodynamic forces by electro spraying method by being prepared such as diluting the resist solutions with cyclopentanone, which is its solvent, in different proportions and in the form of 1: 1-2:1 etc. by volume and subjecting it to electro-spray treatment, and depositing it in the form of droplets-particles directly on the surfaces to be placed on the collector (expressing the drum part where the sample (2) is located in the electrospin device used in the electrospray process and on which the substrate is fixed),

[0116] • Lithography / maskless lithography / nano for the purpose of a second label layer (the situation intended to be expressed here, the main purpose of the photolithography process is to shape the solution called resist and in which we cover the surface with the use of a light source or electrons of appropriate wavelengths. For the resist working in a negative tone, this process is carried out by clinging and forming the shape of the resist on the surface by cross-linking.) cross-linking of the resist accumulating at random locations on the surface by the printing method (When the resist interacts with UV light, photoacid generators in the resist are activated, this activates resin-based chemical monomers and starts to bond with the end part that wants to bond within the chemical structure, and as a result, a stable resist structure is obtained on the surface with the realization of a cross-linking. In other words, this situation does not occur in the points that do not interact with the light, and these nonbonding parts in the developer solution form a bond with the solution and are ultimately removed from the surface) and by washing with the developer and removing from the surface, creating multi-layered security barcodes patterned on the surface in desired geometries (formation of irregular polygonal (such as hexagonal, octagonal) structures and formation of circular structures in general have been observed).

[0117] Lithography is performed to transfer the pattern structure determined as barcode on the surface after the production of random patterns that exhibit the desired characteristic features (for example, particles in random locations in each microscope image taken, particles with different geometry, structures that show different color formation according to their size when subjected to heat treatment, exhibit a characteristic structure that cannot be repeated for each particle).

[0118] The above-mentioned lithography method can be applied in the invention with or without a mask.

[0119] Based on the detailed information above, the invention in question is a security label with a deterministic and stochastic working logic, characterized in that it comprises the following:

[0120] • At least one inner layer shaped by lithography, which cannot be physically cloned with a resist coating that provides randomness,

[0121] • At least one deterministic outer layer with barcode structure, which is the first matching layer and has different shapes formed by the resist structure in random position, geometry and colors formed by the resistive structure on the surface. Other preferred embodiments of the invention comprise the following:

[0122] • The resist coating is a resist coating made by electro-spraying Different dyes or polymers in order to increase the number of security layers.

[0123] • The mentioned dyes are Rhodamine, Coumarin, Methylene Blue or Quantum dots.

[0124] • The inner layer has random colors to be used as a security label in the inner layer.

[0125] • The QR code serving as a deterministic security label for reading the outer layer using a smart device or camera is barcode, QR code, shape or text.

[0126] A security label production method with deterministic and stochastic working logic characterized in that it comprises the following:

[0127] • Making a resist coating with a coating method that will provide randomness in order to create the inner layer, which is one of the two layers that create a security label, to be physically unclonable,

[0128] • Creating the barcode structures in the outer layer by means of an interface of the lithography shaping and image processing, matching and verification method of the coated resist structure.

[0129] The resist mentioned in the method is a polymer-based solution coated on the surface.

[0130] The resist, which can be shaped by the lithography mentioned in the art, is applied on the surface by accumulating at random locations, not as film.

[0131] The coating method with randomness mentioned in the method is the application of the electro-spraying method or the crystallization method using crystalline polymers with random irradiation in order to obtain at random locations by providing nanomicro -sized particle formation at random locations on the surface.

[0132] Photolithography, laser printing lithography, electron beam lithography, masked or maskless lithography methods are used instead of the lithography method mentioned in the method.

[0133] The invention comprises the following:

[0134] • Creating nanomicro-sized structures preferably by electro spraying,

[0135] • Creating barcode structure with lithography method (masked or maskless),

[0136] • Using random structures created by electro spraying method as physically unclonable security labels, • Using lithography method for the production of multi-layered security label,

[0137] • Submitting a security label that is compatible with the integrated circuit production and produced during the fabrication process,

[0138] • Creating an inner layer with multiple security layers with random structures with multiple properties created on the same surface with the electro spraying method,

[0139] • Increasing the number of security layers by adding different dyes (can be dyes such as rhodamine, coumarin, methylene blue and quantum dot) or polymers,

[0140] • Using the random colors formed in the inner layer as a security label,

[0141] • A combination of many different methods (for example, the acquisition of random structures in the interior with electrospray and the photolithography step were mentioned above, alternatively, crystal structures called dwet can be formed on the surface as an alternative to the electrospray method. In this case, randomly radiating crystals can be obtained. As an alternative to the photolithography method, similar procedures can be performed with electron beam lithography. In summary, there are options such as photolithography, laser, maskless lithography, electron beam lithography with any coating that will create randomness (including random dripping on the surface, many coating methods) and lithography methods.

Claims

CLAIMS1. A security label with deterministic and stochastic working logic, characterized in that it comprises the following elements:• At least one inner layer shaped by lithography, which cannot be physically cloned with a resist coating that provides randomness,• At least one deterministic outer layer with barcode structure, which is the first matching layer with different shapes formed by the entire resist structure in random positions, geometries and colors formed by the resist structure on the surface.

2. The security label according to Claim 1, characterized in that said resist coating is a resist coating made by electro-spraying or crystalline polymer.

3. The security label according to Claim 1, characterized in that it has different dyes or polymers in order to increase the number of security layers.

4. The security label according to Claim 1, characterized in that said dyes are rhodamine, coumarin, methylene blue or quantum dot.

5. The security label according to Claim 1, characterized in that the inner layer has random colors for use as a security label in its inner layer.

6. The security label according to Claim 1, characterized in that said outer layer is a QR code, barcode, 2-d barcode, shape or text that serves as a deterministic security label for reading using a smart device or camera.

7. The security label production method with deterministic and stochastic working principles, characterized in that it comprises the following process steps:• Making a resist coating with a coating method that will provide randomness in order to create the inner layer, which is one of the two layers that create a be physically unclonable security label,• Creating the barcode structures in the outer layer by means of an interface of the lithography patterning and image processing, matching and verification method of the coated resist features.

8. The method according to Claim 7, characterized in that said resist is a surface-coated polymer-based solution.

9. The method according to Claim 7, characterized in that the resist, which can be patterned by lithography, is applied on the surface by accumulating at random locations, not as a normal film.

10. The method according to Claim 7, characterized in that the coating method comprising randomness is an electro -spraying method for obtaining at random locations by providing nano-micro-sized particle formation at random locations on the surface or a crystallization method using crystalline polymers with random irradiation.

11. The method according to Claim 7, characterized in that photolithography, laser printing lithography, electron beam lithography, masked or maskless lithography methods are used instead of the lithography method mentioned in the method.

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