Micro-nano turing spot based puf and preparation and transfer method

Abstract

The application discloses a PUF based on a micro-nano Turing spot, and a preparation and transfer method of the PUF. The PUF based on the micro-nano Turing spot is composed of a substrate and a micro-nano Turing spot located on the substrate. The PUF based on the micro-nano Turing spot is formed by a spontaneous generation of a thin film internal chemical reaction and a physical diffusion process. The PUF not only has strong microscopic randomness, but also has a fingerprint-like feature, and can be compatible with a fingerprint feature recognition authentication algorithm. The PUF also has an ultrathin size, is not limited by the substrate, can be transferred and embedded into various irregular substrates and system devices, and has a wide application scenario.

Description

Technical Field

[0001] This invention relates to the fields of hardware security, identity authentication, and anti-counterfeiting encryption, specifically to physically unclonable functions based on micro-nano Turing patterns and their preparation and transfer methods. Technical Background

[0002] Physically Unclonable Functions (PUFs), as an emerging hardware security technology, possess unique and unclonable characteristics. PUFs utilize the massive number of uncontrollable degrees of freedom inherent in micro- and nano-manufacturing processes, ensuring that even the manufacturer cannot replicate a PUF entity with identical features. In recent years, PUFs have been validated in applications such as identity authentication, random number generation, communication encryption, and anti-counterfeiting, and are beginning to demonstrate significant application value in fields such as the Internet of Things, integrated circuits, and low-altitude economic security.

[0003] Optical PUFs, as the earliest proposed PUF technology, possess advantages such as high entropy content, simple fabrication, convenient readout, and resistance to machine learning attacks. However, most currently reported optical PUFs, once fabricated, are difficult to transfer between different substrates and are also difficult to fabricate on irregular curved surfaces, limiting their application range. For example, if it is necessary to embed PUFs in certain valuable items or devices, conventional optical PUF fabrication methods are difficult to apply. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a PUF based on micro-nano Turing patterns, as well as a method for the preparation and transfer of the PUF. The aim is to obtain a flexible and practical PUF that can be transferred between different types of substrates and devices through a low-cost, simple and easy-to-implement preparation method that is compatible with semiconductor micro-nano processes, so as to overcome the problems faced by current optical PUFs and meet the flexible and diverse practical application needs.

[0005] The objective of this invention is achieved through the following technical solution: a PUF based on micro-nano Turing patterns, which consists of a substrate and micro-nano Turing patterns located on the substrate. The substrate may be a rigid substrate or a flexible substrate, and the substrate may be a planar substrate or a curved substrate.

[0006] A reaction layer is spin-coated, deposited, or grown on a substrate, and a micro / nano Turing pattern is generated on the reaction layer. The micro / nano Turing pattern is a stripe and spot with a spatially random curved distribution that is spontaneously generated by chemical reactions and physical diffusion processes within the reaction layer.

[0007] The reaction layer is covered with a capping layer.

[0008] Another object of the present invention is to provide a method for preparing PUF based on micro / nano Turing patterns, which includes the following steps:

[0009] Step 1: Spin-coating, depositing, or growing a reactive layer on the substrate;

[0010] Step 2: Define the PUF region on the reactive layer by photolithography, and remove the reactive layer from the non-PUF regions;

[0011] Step 3: Coat, deposit, or grow a capping layer on the reactive layer;

[0012] Step 4: React the reaction layer of the PUF region with the reaction gas, reaction solution, or light, heat, force, electricity, or magnetic stimulation to generate micro-nano Turing patterns, thus obtaining a PUF based on micro-nano Turing patterns.

[0013] The present invention provides a PUF transfer method based on micro / nano Turing patterns, comprising the following steps:

[0014] S1. Prepare a reaction layer and a capping layer on a substrate;

[0015] S2. Generate micro-nano Turing patterns on the reaction layer to obtain PUF based on micro-nano Turing patterns;

[0016] S3. Cover the upper surface of the PUF based on micro-nano Turing patterns with a transfer layer;

[0017] S4. Peel the reaction layer, capping layer and transfer layer from the substrate;

[0018] S5. Remove the reaction layer;

[0019] S6. Transfer the transfer layer and cover layer to the surface of other items or devices.

[0020] The beneficial effects of this invention are:

[0021] (1) The PUF formation process based on micro-nano Turing patterns proposed in this invention is spontaneously generated by chemical reactions and physical diffusion processes inside the thin film. It not only has strong micro-randomness, but also has fingerprint-like characteristics and is compatible with fingerprint feature recognition and authentication algorithms.

[0022] (2) The PUF based on micro-nano Turing patterns proposed in this invention has an ultra-thin size and is not limited by the substrate. It can be transferred and embedded into various irregular substrates and system devices for use, and has a wide range of application scenarios.

[0023] (3) The proposed PUF preparation method based on micro-nano Turing patterns is compatible with semiconductor processes, low in cost, simple and easy to implement, and can be prepared in large-area batches. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a Turing pattern PUF based on photoresist and a gold thin film and its fabrication method. Wherein: 11 is the Si substrate; 12 is the photoresist; 13 is the gold thin film.

[0025] Figure 2 This is a Turing pattern PUF micrograph prepared according to the present invention based on photoresist and gold thin film.

[0026] Figure 3 The statistical results of the inter-Hamming wafer distances of 100 Turing pattern PUFs based on photoresist and gold thin films prepared in this invention are presented.

[0027] Figure 4 The statistical results of the intra-chip distance of the Turing pattern PUF based on photoresist and gold thin film prepared in this invention are shown.

[0028] Figure 5 A schematic diagram of Turing pattern PUFs based on photoresist and two-dimensional materials and their fabrication methods.

[0029] Figure 6 This is a schematic diagram of the Turing pattern PUF transfer method proposed in this invention. Wherein: 31 is the substrate; 32 is the reaction layer film; 33 is the capping layer film; 34 is the transfer layer; and 35 is the device surface. Detailed Implementation

[0030] The micro-nano Turing patterns described in this invention are stripes and spots with a spatially random curved distribution, spontaneously generated by chemical reactions and physical diffusion processes within the reaction layer.

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figure 1 As shown, a PUF based on micro-nano Turing patterns consists of a rigid Si substrate 11 and micro-nano Turing patterns located on the Si substrate; a 1μm thick photoresist 12 is spin-coated on the Si substrate 11 as a reactive layer film, and a PUF region pattern is formed on the photoresist 12 using a photomask and ultraviolet lithography, and the photoresist in the non-PUF regions is removed by development; a metal capping layer 13 is covered on the PUF region pattern.

[0034] The preparation process of this PUF is as follows:

[0035] Step 1: Spin-coat a 1 μm thick layer of photoresist onto the Si substrate 11 as a reaction layer;

[0036] Step 2: Use a photomask and ultraviolet lithography to form a PUF area pattern on the reactive layer, and develop to remove the photoresist in the non-PUF areas;

[0037] Step 3: Electron beam evaporation is used to deposit Ti and Au with thicknesses of 10 nm and 100 nm respectively on the photoresist as metal capping layers 13; Ti is used to increase the adhesion of Au, and the two TiAu layers together serve as the metal capping layer.

[0038] Step 4: Immerse the sample in acetone solution. The acetone solution penetrates through the gaps in the metal capping layer and between the metal and the photoresist, reacting with the photoresist. The reaction between the photoresist and the acetone solution generates wrinkling stress, causing random micro-wrinkles in the photoresist / TiAu bilayer film, forming Turing patterns. The pattern size and morphology of the formed micro / nano Turing patterns can be controlled by adjusting the reaction time. Remove the prepared sample and dry it to obtain a micro / nano Turing pattern PUF based on photoresist and a metal film.

[0039] Figure 2 These are optical micrographs (left) and electron micrographs (right) of the Turing pattern PUF prepared in this embodiment based on photoresist and metal thin film. It can be seen that the stripes and spots with a line width of about 3 μm are randomly curved and distributed, similar to micro fingerprints.

[0040] One hundred Turing patch images (PUFs) prepared using the method in Example 1 were read using an optical microscope, and quantitative statistical analysis was performed to obtain the inter-pattern Hamming distance and intra-pattern Hamming distance, as shown below. Figure 3 and Figure 4 As shown in the figure. The results show that the inter-chip Hamming distance is between 0.5 ± 0.015, which proves that the prepared PUF is unique; the intra-chip Hamming distance is less than 0.18, which proves that the same PUF is reproducible and robust; these results prove that the different prepared PUFs are significantly distinguishable and can be used for authentication and anti-counterfeiting.

[0041] Example 2

[0042] like Figure 5 As shown, a PUF based on micro-nano Turing patterns consists of a flexible PET plastic substrate 21 and micro-nano Turing patterns on the PET plastic substrate 21. A 5μm thick photosensitive polymer 22 is spin-coated on the PET plastic substrate 21 as a reaction layer, and a PUF region pattern is formed on the photosensitive polymer using a photomask and ultraviolet lithography. The photoresist in the non-PUF regions is removed by development. Finally, an MXene two-dimensional material is grown on the photosensitive polymer as a capping layer 23 using an electrochemical etching method.

[0043] The preparation process of this PUF is as follows:

[0044] Step 1: Spin-coat a 5 μm thick layer of photosensitive polymer onto a PET plastic substrate 21 as a reaction layer 22;

[0045] Step 2: Use a photomask and ultraviolet lithography to form a PUF region pattern on the photosensitive polymer, and develop and remove the non-PUF regions of the photosensitive polymer.

[0046] Step 3: An MXene two-dimensional material is grown on a photosensitive polymer as a capping layer 23 using an electrochemical etching method;

[0047] Step 4: Irradiate the entire sample from the back (i.e., the bottom surface of the substrate) with a laser to stimulate the photosensitive polymer. Under the stimulation of the laser, the photosensitive polymer generates wrinkle stress, causing random micro-wrinkles in the photosensitive polymer / MXene two-dimensional material to form Turing patterns. By controlling the laser power and stimulation time, the pattern size and morphology of the formed micro-nano Turing patterns are adjusted to obtain a PUF based on the micro-nano Turing patterns.

[0048] Example 3

[0049] like Figure 6 As shown, the present invention provides a PUF transfer method based on micro-nano Turing patterns, which utilizes micro-transfer technology to transfer the formed micro-nano Turing patterns onto other articles or devices. Specifically, it includes the following steps:

[0050] S1. Prepare a reaction layer 32 and a capping layer 33 on a substrate 31;

[0051] S2. Generate micro-nano Turing patterns on the reaction layer 32 to obtain a PUF based on micro-nano Turing patterns;

[0052] S3. A transfer layer 34 is applied to the upper surface of the PUF based on micro-nano Turing patterns;

[0053] S4. Peel the reaction layer 32, the capping layer 33 and the transfer layer 34 from the substrate 31;

[0054] S5. Remove the reaction layer 32. The coating layer solidifies after forming wrinkles. Removing the reaction layer will not affect the wrinkles that have already formed.

[0055] S6. Transfer the transfer layer 34 and the cover layer 33 to the surface of other articles or devices 35.

[0056] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A PUF based on micro / nano Turing patterns, characterized in that, It consists of a substrate and micro / nano Turing patterns located on the substrate.

2. The PUF based on micro / nano Turing patterns as described in claim 1, characterized in that, The substrate may be a rigid substrate or a flexible substrate, and the substrate may be a planar substrate or a curved substrate.

3. The PUF based on micro / nano Turing patterns as described in claim 1, characterized in that, A reaction layer is spin-coated, deposited, or grown on a substrate to generate micro / nano Turing patterns on the reaction layer.

4. The PUF based on micro / nano Turing patterns as described in claim 3, characterized in that, The micro-nano Turing patterns are stripes and spots with a spatially random, curved distribution, spontaneously generated by chemical reactions and physical diffusion processes within the reaction layer.

5. The PUF based on micro / nano Turing patterns as described in claim 3, characterized in that, The reaction layer is covered with a capping layer.

6. A method for preparing PUF based on micro / nano Turing patterns, used to prepare PUF based on micro / nano Turing patterns as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Spin-coating, depositing, or growing a reactive layer on the substrate; Step 2: Define the PUF region on the reactive layer by photolithography, and remove the reactive layer from the non-PUF regions; Step 3: Coat, deposit, or grow a capping layer on the reactive layer; Step 4: React the reaction layer of the PUF region with the reaction gas, reaction solution, or light, heat, force, electricity, or magnetic stimulation to generate micro-nano Turing patterns, thus obtaining a PUF based on micro-nano Turing patterns.

7. A method for transferring PUFs based on micro / nano Turing patterns, characterized in that, Includes the following steps: S1. Prepare a reaction layer and a capping layer on the substrate; S2. Generate micro-nano Turing patterns on the reaction layer to obtain PUF based on micro-nano Turing patterns; S3. Cover the upper surface of the PUF based on micro-nano Turing patterns with a transfer layer; S4. Peel the reaction layer, capping layer and transfer layer from the substrate; S5. Remove the reaction layer; S6. Transfer the transfer layer and cover layer to the surface of other items or devices.

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