A method for preparing a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect

Abstract

The application relates to a preparation method of a temperature-sensitive multilayer film structure with a multi-mode infrared anti-counterfeiting effect, and the specific steps are as follows: after a silicon wafer substrate is washed, the silicon wafer substrate is dried by blowing; Al is deposited on the silicon wafer substrate layer as a metal high-reflection layer; then Si is deposited on the metal high-reflection layer as a spacing layer and annealing treatment is carried out; V2O5 is deposited on the spacing layer as a phase change material layer and annealing treatment is carried out; finally, an Al top layer pattern layer composed of Al with different thicknesses is deposited on the structure surface according to the pattern requirement, and a temperature-sensitive multilayer film is obtained. The temperature-sensitive multilayer film can automatically adjust the heat emission pattern according to the temperature, does not need fluorescence excitation, and is not easy to be washed off. The application also designs an anti-counterfeiting pattern for the transition state of the phase change material layer, constructs the anti-counterfeiting effect of multiple modes, and enhances the camouflage effect. The preparation process of the application is simple, does not need micro-nano processing such as etching, is low in cost, is suitable for batch application, and has a wide application prospect in the fields of anti-counterfeiting encryption and stealth.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat radiation control and anti-counterfeiting, and particularly relates to a preparation method of a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect. BACKGROUND

[0002] Digital information is constantly penetrating into various fields of society, and cases of information leakage occur frequently. A large number of counterfeit and inferior products, including electronic products, currency, fuel, and medicines, have flooded the market, seriously endangering market safety and affecting the brand image of enterprises and the rights and interests of consumers. Therefore, it is urgent to develop a technology with large information storage capacity and high anti-counterfeiting encryption level.

[0003] Existing anti-counterfeiting technologies mainly rely on printing technology of colorless or light-colored luminescent materials (CN218996231U, CN114714792A); however, the luminescence waveband of these patterns is limited to the visible light waveband, and can be identified by the naked eye, which can be easily replaced by materials with similar luminescent properties; in addition, organic dyes often lack rigid structures and have poor chemical stability and are easily washed off.

[0004] A temperature-sensitive dynamic variable-emissivity anti-counterfeiting structure relying on phase change materials can further break through the limitations of luminescent materials, and its structure infrared emissivity changes under the stimulation of different temperatures, and an infrared thermal imaging camera can capture anti-counterfeiting patterns at different temperatures (CN113314020B); however, the anti-counterfeiting patterns designed based on phase change materials often have only two modes (CN113990176B), and micro-nano processing technologies such as photolithography and etching are often used, which is not conducive to large-scale manufacturing and application. Therefore, it is desirable to find a preparation method of a multi-mode anti-counterfeiting film with a simple preparation process and temperature-sensitive dynamic variable-emissivity. SUMMARY

[0005] The application aims to solve the above technical problems, and provides a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect.

[0006] The technical scheme of the application is a preparation method of a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect, and the specific steps are as follows:

[0007] S1: After the silicon wafer substrate is soaked in HF, it is washed with deionized water and then dried with a nitrogen gun;

[0008] S2: Al is deposited as a metal high-reflection layer on the silicon wafer substrate layer in step S1 by resistance evaporation deposition;

[0009] S3: Si is deposited as a spacer layer on the metal high-reflection layer in step S2 by electron beam evaporation deposition, and is subjected to annealing treatment;

[0010] S4: depositing V2O5 as a phase-change material layer on the interval layer in step S3 by electron beam evaporation, and converting V2O5 into VO2 by annealing treatment;

[0011] S5: depositing an Al top layer pattern layer composed of Al with different thicknesses on the structure surface in step S4 according to the pattern requirement.

[0012] Preferably, the mass concentration of HF used in step S1 is 40-55%; and the soaking time is 10-20 min.

[0013] Preferably, the thickness of the metal high-reflection layer in step S2 is 70-100 nm.

[0014] Preferably, the thickness of the interval layer in step S3 is 100-170 nm.

[0015] Preferably, the thickness of the phase-change material layer in step S4 is 90-120 nm.

[0016] Preferably, the thickness of the Al top layer pattern layer in step S5 is 2-20 nm.

[0017] Preferably, the resistance evaporation rate for depositing the metal high-reflection layer in step S2 is

[0018] Preferably, the electron beam evaporation rate for depositing the interval layer in step S3 is The annealing treatment is performed under N2 environment, the annealing temperature is 300-350℃, and the annealing time is 2-2.5 h.

[0019] Preferably, the electron beam evaporation rate for depositing the phase-change material layer in step S4 is The annealing treatment is performed under N2 environment, the annealing temperature is 400-440℃, and the annealing time is 2.5-3 h.

[0020] Preferably, the resistance evaporation rate for depositing the Al top layer pattern layer in step S5 is The thickness of the pattern is 2-20 nm.

[0021] The application further provides a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect, which is prepared by the method for preparing a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect.

[0022] The present application regulates the degree of closure of the constructed F-P cavity and the local intensity of infrared light by changing the thickness of the Al top layer, so as to obtain the infrared emissivity of different regions of the pattern, so that different thermal emission temperatures are presented under the same ambient temperature, and a multi-mode infrared anti-counterfeiting pattern is constructed. At the same time, the change rate of the local intensity of infrared light of the F-P cavity with different degrees of closure is different with the change of temperature and the change of the properties of the phase change layer material, so that the relative infrared emissivity of different regions changes with temperature, thereby obtaining the multi-mode anti-counterfeiting effect of different infrared imaging patterns under different temperature excitation. Compared with the traditional fluorescent anti-counterfeiting pattern, the temperature-sensitive multilayer film of the present application can automatically adjust the thermal emission pattern according to the temperature, without the need for fluorescent excitation, and is not easy to be washed off. Compared with the simple double-mode anti-counterfeiting technology, the present application also designs corresponding anti-counterfeiting patterns for different transition states of the phase change material VO2 layer, thereby realizing multiple modes of infrared imaging patterns at multiple temperatures, constructing multiple modes of anti-counterfeiting effects, and enhancing the performance of anti-counterfeiting encryption. In addition, the preparation process of the present application is simple, does not need to be etched and other micro-nano processing, has low cost, is suitable for batch application, and has wide application prospect in the fields of anti-counterfeiting encryption and stealth.

[0023] Beneficial effects: Compared with the traditional fluorescent anti-counterfeiting pattern, the temperature-sensitive multilayer film of the present application can automatically adjust the thermal emission pattern according to the temperature, without the need for fluorescent excitation, and is not easy to be washed off. Compared with the simple double-mode anti-counterfeiting technology, the present application also designs anti-counterfeiting patterns for the transition state of the phase change material layer, thereby constructing multiple modes of anti-counterfeiting effects and enhancing the camouflage effect. In addition, the preparation process of the present application is simple, does not need to be etched and other micro-nano processing, has low cost, is suitable for batch application, and has wide application prospect in the fields of anti-counterfeiting encryption and stealth. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a cross-sectional structure schematic diagram of the anti-counterfeiting multilayer film of the embodiment of the present application; wherein: 11 is a substrate layer, 12 is a high-reflection metal layer, 13 is a spacer layer, 14 is a phase change material layer, and 15 is an Al top layer pattern layer;

[0025] Figure 2 It is the multi-mode infrared anti-counterfeiting effect of embodiments 1-3 of the present application. Wherein a is embodiment 1, b is embodiment 2, and c is embodiment 3. DETAILED DESCRIPTION

[0026] The specific embodiments of the present application will be described in detail below in conjunction with the drawings: The present embodiment case takes the temperature-sensitive multilayer film structure of the multi-mode infrared anti-counterfeiting effect of the present application as the premise, but the protection scope of the present application is not limited to the following embodiments and cases.

[0027] The structure schematic diagram of the embodiment of the present application is as follows Figure 1As shown, including substrate layer 11, high reflection metal layer, spacer layer 13, phase change material layer 14 and Al top layer pattern layer 15.

[0028] This embodiment uses three different temperature-sensitive multilayer film patterns to control the infrared band thermal radiation pattern at different temperatures.

[0029] Example 1

[0030] The silicon wafer is selected as the substrate, and the specific preparation process is as follows:

[0031] The silicon wafer substrate is soaked in 40% HF for 20 min, washed with deionized water and dried with a nitrogen gun;

[0032] A 70nm Al film is deposited on the treated silicon wafer by resistance evaporation, and the evaporation rate is

[0033] A 170nm Si film is deposited on the Al film by electron beam evaporation, and the evaporation rate is Annealing at 350°C for 2h in N2 environment to obtain a crystalline Si film;

[0034] A 120nm V2O5 film is deposited on the Si film by electron beam evaporation, and the evaporation rate is Annealing at 440°C for 3h in N2 environment to obtain a phase change material VO2 film;

[0035] A 2nm square Al film is deposited on the VO2 film by resistance evaporation, and the evaporation rate is

[0036] Example 2

[0037] The silicon wafer is selected as the substrate, and the specific preparation process is as follows:

[0038] The silicon wafer substrate is soaked in 50% HF for 15 min, washed with deionized water and dried with a nitrogen gun;

[0039] An 80nm Al film is deposited on the treated silicon wafer by resistance evaporation, and the evaporation rate is

[0040] A 130nm Si film is deposited on the Al film by electron beam evaporation, and the evaporation rate is Annealing at 300°C for 2.5h in N2 environment to obtain a crystalline Si film;

[0041] A 100nm V2O5 film is deposited on the Si film by electron beam evaporation, and the evaporation rate is Annealing at 400 ℃ for 3 h under N2 environment to obtain a phase-change material VO2 film;

[0042] A 3 nm square Al film is deposited on the VO2 film by resistance evaporation, and a 5 nm square Al film and a 20 nm square Al film are sequentially deposited by the same method as the Al top pattern layer, with an evaporation rate of

[0043] Example 3

[0044] A silicon wafer is selected as the substrate, and the specific preparation process is as follows:

[0045] The silicon wafer substrate is soaked in 55% HF for 10 min, washed with deionized water, and then dried with a nitrogen gun;

[0046] A 100 nm Al film is deposited on the treated silicon wafer by resistance evaporation, with an evaporation rate of

[0047] A 100 nm Si film is deposited on the Al film by electron beam evaporation, with an evaporation rate of Annealing at 300 ℃ for 2 h under N2 environment to obtain a crystalline Si film;

[0048] A 90 nm V2O5 film is deposited on the Si film by electron beam evaporation, with an evaporation rate of Annealing at 440 ℃ for 2.5 h under N2 environment to obtain a phase-change material VO2 film;

[0049] A 10 nm square Al film is deposited on the VO2 film by resistance evaporation, and a 3 nm square Al film and a 15 nm square Al film are sequentially deposited by the same method as the Al top pattern layer, with an evaporation rate of

[0050] The multi-mode anti-counterfeiting performance of the samples obtained in Examples 1-3 is detected as shown in Figure 2 The infrared thermal images show that the samples of different examples exhibit different thermal pattern changes under different temperature excitations, and the change modes are different in different examples. As shown in Figure 2 a, the pattern of Example 1 presents a relatively deep-dark-deepest pattern from left to right at 65 ℃, the color of the deepest region changes to the middle square at 67 ℃, and the colors of the regions are slightly close to each other, and the deepest region changes to the leftmost square at 70 ℃. As shown in Figure 2 b, the colors of the regions of Example 2 are nearly uniform at 60 ℃, the color of the left region is lighter than that of the middle and right regions at 65 ℃, and a shallow-deep-deepest gradient pattern is presented at 67 ℃. As shown in Figure 2As shown in Fig. c, the color of each region of Example 3 is very close at 55℃, only the middle region is slightly lighter at 65℃, and it changes back to nearly uniform light color at 75℃. This is due to the thickness variation of the Al top layer pattern layer, which regulates the degree of closure of the constructed F-P cavity and its local intensity to infrared light, presents different thermal emission temperatures at the same temperature, and constructs an infrared anti-counterfeiting pattern. With the change of temperature, the local effect of the constructed F-P cavity on infrared light changes with the change of the optical properties of the phase change material layer, and the change rate of each region is not the same, thereby presenting a multi-mode anti-counterfeiting effect at different temperatures.

[0051] Therefore, the temperature-sensitive multilayer film structure of the present application exhibits a multi-mode thermal infrared anti-counterfeiting pattern at different temperatures, and can realize the effect of multi-mode anti-counterfeiting.

Claims

1. A method for preparing a temperature-sensitive multilayer film structure with multi-mode infrared anti-counterfeiting effect, comprising the following steps: S1: soaking the silicon substrate in HF, then washing with deionized water and blowing dry with a nitrogen gun; S2: depositing Al as a metal high-reflection layer on the silicon substrate layer in step S1 by resistance evaporation; S3: depositing Si as a spacer layer on the metal high-reflection layer in step S2 by electron beam evaporation, and performing annealing treatment; S4: depositing V2O5 as a phase change material layer on the spacer layer in step S3 by electron beam evaporation, and performing annealing treatment, wherein V2O5 is converted into VO2; S5: depositing an Al top layer pattern layer composed of Al with a thickness of 2-20 nm on the surface of the structure in step S4 according to the pattern needs.

2. The method of claim 1, wherein: The mass concentration of HF used in step S1 is 40-55%, and the soaking time is 10-20 min.

3. The method of claim 1, wherein: The thickness of the metal high-reflection layer in step S2 is 70-100 nm.

4. The method of claim 1, wherein: The thickness of the spacer layer in step S3 is 100-170 nm.

5. The method of claim 1, wherein: The thickness of the phase change material layer in step S4 is 90-120 nm.

6. The method of claim 1, wherein: The resistance evaporation rate for depositing the metal high-reflection layer in step S2 is 0.6-1.0 Å / s.

7. The method of claim 1, wherein: The electron beam evaporation rate for depositing the spacer layer in step S3 is 0.8-1.2 Å / s, and the annealing treatment is performed in N2 environment at an annealing temperature of 300-350℃ for 2-2.5 h.

8. The method of claim 1, wherein: The electron beam evaporation rate for depositing the phase change material layer in step S4 is 0.6-1.2 Å / s, and the annealing treatment is performed in N2 environment at an annealing temperature of 400-440℃ for 2.5-3 h.

9. The method of claim 1, wherein: The resistance evaporation rate for depositing the Al top layer pattern layer in step S5 is 0.6-1.0 Å / s.

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