TWI710535B - Sapphire coated substrate with a flexible, anti-scratch and multi-layer coating and a method for preparing the same - Google Patents

Abstract

A method for forming a substrate with a multi-layered, flexible, and anti-scratch metal oxides protective coating being deposited onto the substrate is provided in the present invention, wherein the top most layer of the coating comprises Al₂O₃ or a mixture thereof such that the top most layer acts as an anti-scratching layer. The multi-layered, flexible and anti-scratch metal oxides protective coating also retains the flexibility of the underlying substrate.

Description

Sapphire coated substrate with flexible, scratch-resistant and multilayer coating and preparation thereof method

The present invention relates to a method for depositing a composition of a multilayer metal oxide protective coating on a substrate, wherein the top layer is Al ₂ O ₃ or a mixture thereof, and the top layer is used as a scratch-resistant layer. The multilayer metal oxide protective coating can also maintain the flexibility of the underlying substrate.

Sapphire is currently actively used as the screen of smartphones and tablet computers. It is the second hardest material after diamonds. Therefore, using sapphire as the screen means that smartphones/tablets have superior scratch resistance and Crack resistant screen. The sapphire screen is a feature of the iPhone 5S (iPhone 5S), which is used in the TouchID scanner and the camera lens behind the phone. And Vertu, the manufacturer of luxury smartphones, is also developing sapphire screens. However, since sapphire is the second hardest material, it is also difficult to cut and polish. In fact, the growth of large-size single crystal sapphire is quite time-consuming, which leads to long manufacturing time and high manufacturing cost. Due to the high manufacturing cost and long manufacturing time of sapphire screens, Apple only uses sapphire in Apple Watches.

The commonly used "toughened" screen material is Gorilla Glass made by Corning, which has been used on more than 1.5 billion devices. In fact, sapphire is more difficult to scratch than Gorilla Glass, and this has been verified by many third-party organizations, such as Ah The Center for Advanced Ceramic Technology at Kazuo Inamori School of Engineering at Alfred University. On the Mohs scale of hardness, the latest Gorilla Glass has a Mohs hardness of only 6.5 Mohs, which is lower than the Mohs hardness of mineral quartz, so Gorilla Glass is still easily scratched by sand or metal. Sapphire is the second hardest material naturally produced on the earth, second only to diamonds with a Mohs hardness of 10 on the mineral Mohs hardness scale.

The Mohs hardness test is the ability of harder materials to scratch softer materials to characterize the scratch resistance of minerals. This test compares the ability of one substance to scratch other substances, so compared to crack resistance, this test is a better indicator of scratch resistance. It is shown in Figure 1.

The following is quoted from "Display Review": "Chemically strengthened glass can be very good, but sapphire is better in terms of hardness, strength and toughness." Hall explained, adding that "the fracture toughness of sapphire should be It is about four times higher than Gorilla Glass, which is about 3MPa-m0.5 and 0.7MPa-m0.5 respectively. 』

Nevertheless, this is accompanied by some considerable disadvantages. Sapphire is not only heavier, it has 3.98g per cubic centimeter (compared to 2.54g of Gorilla Glass), and it refracts slightly more light.

In addition to being heavy, sapphire, which is the second hardest, is also a material that is difficult to cut and polish. It is quite time-consuming to grow single crystal sapphire, especially when the diameter is larger (greater than 6 inches), which is very technically challenging. Therefore, the manufacturing cost of the sapphire screen is high and the manufacturing time is long. The purpose of the present invention is to provide a method for manufacturing sapphire screen material, which is fast and low-cost, and has the following advantages: ● Harder than any hardened glass; ● Less likely to break than a pure sapphire screen; ●The weight is lighter than the pure sapphire screen; ●The transparency is higher than the pure sapphire screen.

In order to harden the sapphire (Al ₂ O ₃ ) film deposition, the softening/melting temperature of the softer substrate should be high enough and higher than the annealing temperature. Most rigid substrates, such as quartz and fused silica, can meet this requirement. However, flexible substrates such as polyethylene terephthalate (PET) cannot meet this requirement. The melting temperature of PET is about 250°C, which is much lower than the annealing temperature. PET is one of the most widely used flexible substrates. The ability to transfer Al ₂ O ₃ (sapphire) film substrates to softer flexible substrates will significantly expand its application range from rigid substrates such as glass and metal to flexible substrates such as PET , Polymers, plastics, paper, and even fabrics can then improve the mechanical properties of the transferred substrate. Therefore, the Al ₂ O ₃ film is transferred from the rigid substrate to the flexible substrate, which can avoid the problem that the melting temperature of the flexible substrate is usually low.

More importantly, many substrates used in smart displays today are also flexible, and such flexible substrates are usually soft and prone to deterioration due to environmental factors. The purpose of the present invention is to prepare a composition of a multilayer metal oxide protective coating deposited on a substrate, wherein the topmost layer is Al ₂ O ₃ or a mixture thereof, so that this topmost layer also serves as a scratch-resistant layer. The multilayer metal oxide protective coating also maintains the flexibility of the underlying substrate.

According to the first aspect of the present invention, it proposes a method for forming a substrate with a flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate. The coating includes: combining two different metals An oxide layer is deposited on the substrate as layer 101 and layer 102, wherein the thickness of the metal oxide layer 101 ranges from 1 nm to 50 nm, and the thickness of the metal oxide layer 102 ranges from 10 nm to 2000 nm; and an Al The final top layer 105 of ₂ O ₃ or its mixture is deposited on the two different metal oxide layers, the mixture containing a metal selected from Mg, Si or AF, or selected from Si oxide, Ti oxide, Cr oxide , Ni oxide, Ag oxide, or Zr oxide, and the thickness of the top layer ranges from 20 nm to 200 nm.

In the first embodiment of the first aspect of the present invention, the method is provided, wherein a metal oxide layer 103 is deposited on the two different metal oxide layers 101, 102 to form three alternating layers. Metal oxide layers 101, 102, 103, wherein the metal oxide layer 103 is the same as the metal oxide layer 101, and wherein the final top layer 105 is deposited on top of the layer 103 to form a metal oxide layer 101, The multilayer structure of 102, 103 and 105.

In the second embodiment of the first aspect of the present invention, the method is provided, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form a Alternate four metal oxide layers 101, 102, 103, 104, wherein the metal oxide layer 104 is the same as the metal oxide layer 102, and the final top layer 105 is deposited on top to form a metal oxide layer 101 , 102, 103, 104 and 105 multilayer structure.

In a third embodiment of the first aspect of the present invention, the method is provided, wherein, before depositing the final top layer 105, at least one of the alternating metal oxide layers is further deposited to form a metal oxide Multi-layer structure.

In a fourth embodiment of the first aspect of the present invention, the method is provided, wherein any one or all of the deposition is performed by a physical vapor deposition method selected from an electron beam evaporation deposition process or a sputter deposition process .

In the fifth embodiment of the first aspect of the present invention, the method is provided, wherein the substrate includes sapphire, quartz, fused silica, gorilla glass, tempered glass, soda lime glass, mineral glass, metal And/or plastic polymer, and any combination thereof, and wherein the plastic polymer Including polymethyl methacrylate (PMMA), polycarbonate, polyethylene terephthalate, and polyimide.

In the sixth embodiment of the first aspect of the present invention, the method is provided, wherein the metal oxide layer 101 or the metal oxide layer 102 is selected from Al oxide, Ti oxide, Cr oxide, Ni Oxide, Si oxide, Ag oxide or Cr oxide, but the two metal oxide layers are different.

According to the second aspect of the present invention, it provides a substrate with a multilayer, flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate, and the coating includes: at least two different The metal oxide layer, which is layer 101 and layer 102, is deposited on the substrate, wherein the thickness of the metal oxide layer 101 ranges from 1 nm to 50 nm, and the thickness of the metal oxide layer 102 ranges from 10 nm to 10 nm. 2000nm; and, a final top layer 105 of Al ₂ O ₃ or a mixture thereof, which is located on two different metal oxide layers, the mixture including a metal selected from Mg, Si or AF, or selected from Si oxide, Metal oxides of Ti oxide, Cr oxide, Ni oxide, Ag oxide or Zr oxide, and wherein the thickness of the top layer ranges from 20 nm to 200 nm.

In the first embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein a metal oxide layer 103 is deposited on the two metal oxide layers 101, 102 to form Three alternate metal oxide layers 101, 102, 103, wherein the metal oxide layer 103 is the same as the metal oxide layer 101, and the final top layer 105 is deposited on top of the layer 103 to form the layers 101 , 102, 103 and 105 multilayer, flexible and scratch resistant coating.

In a second embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form an alternating four metal oxide layers 101, 102, 103, 104, wherein the metal oxide The compound layer 104 is the same as the metal oxide layer 102, and the final top layer 105 is deposited on top of the layer 104 to form a multilayer, flexible and scratch-resistant coating of the layers 101, 102, 103, 104 and 105 .

In the third embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein, before the final top layer 105 is deposited, at least one of the alternating metal oxide layers is further deposited to The multilayer, flexible and scratch resistant coating is formed.

In a fourth embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein the deposition is performed by a physical vapor deposition method including an electron beam evaporation deposition process or a sputter deposition process .

A fifth embodiment of the second aspect of the present invention provides the substrate with the coating, wherein the substrate includes sapphire, quartz, fused silica, Gorilla glass, tempered glass, soda lime glass , One or more of mineral glass, metal, and/or plastic polymer, or any combination thereof, and wherein the plastic polymer includes PMMA, polycarbonate, polyethylene terephthalate, and polyimide .

The sixth embodiment of the second aspect of the present invention provides the substrate with the coating, wherein the metal oxide layer 101 or the metal oxide layer 102 is selected from Al oxide, Ti oxide , Cr oxide, Ni oxide, Si oxide, Ag oxide or Cr oxide, and wherein the two metal oxides are different.

Those skilled in the art should understand that, in addition to those specifically described, various changes and modifications can be made to the present invention described herein.

The present invention includes all such changes and modifications. The present invention also includes all individual or common steps and features referred to or indicated in this specification, as well as any and all combinations or any two or more of these steps or features.

For those skilled in the art, after reviewing the following description, other aspects and advantages of the present invention will be obvious.

100: substrate

101, 102, 103, 104, 105: layer (film)

Through the subsequent description of the present invention and the accompanying drawings, the above and other objectives and features of the present invention will become apparent. Among them: Figure 1 shows the Mohs hardness scale of minerals; Figure 2 shows the comparison General glass, Gorilla glass, quartz and pure sapphire, the top surface hardness of "Sapphire film on quartz"; Figure 3 shows the transmittance of quartz, sapphire film on quartz and pure sapphire; Figure 4 shows the transmittance of quartz and pure sapphire. The transmittance of 190nm sapphire film on quartz annealed at 1300°C for 2 hours and unannealed; Figure 5 shows the XRD results of 400nm sapphire film on quartz annealed at 750°C, 850°C and 1200°C for 2 hours; Figure 6 shows the electron beam transmission spectra of 400nm sapphire film on quartz and sapphire substrates annealed at 1200℃ for 2 hours and unannealed quartz; Figure 7 shows the comparison between quartz and sapphire substrates , The electron beam transmission spectra of 160nm sapphire film annealed at 1150°C for 2 hours and unannealed fused silica; Figure 8A shows the preparation by sputtering deposition and annealing at 850°C, 1050°C and 1200°C for 2 hours XRD results of 400nm sapphire thin films on quartz; Figure 8B shows the XRD results of sapphire thin films with thicknesses of 220nm, 400nm and 470nm on quartz prepared by sputtering deposition and annealing at 1150°C for 2 hours; Figure 9 shows the transmission spectra of 220nm, 400nm and 470nm sapphire films on quartz prepared by sputtering deposition and annealing at 1100°C for 2 hours compared to quartz substrates; Figure 10 shows the transmission spectra of sapphire films deposited by sputtering Compared with the XRD results of 350nm sapphire film on fused silica prepared by annealing at 750℃, 850℃, 1050℃ and 1150℃ for 2 hours; Figure 11 shows the comparison with the fused silica substrate. The transmission spectrum of 180nm-600nm sapphire film on fused silica prepared by annealing at ℃ for 2 hours; Figure 12 shows the transmittance of 250nm annealed sapphire film on fused silica and fused silica, the annealed sapphire film has or does not have 10nm Titanium catalyst was annealed at 700°C and 1150°C for 2 hours; Figure 13A shows the X-ray reflectance (XRR) measurement results of different samples under different annealing conditions; Figure 13B shows different samples under different annealing conditions 14A to 14E show the EBL steps in the manufacture of absorber metamaterials, the disk array device cycle is 600nm, the disk diameter: 365nm, the gold thickness: 50nm and the chromium thickness: 30nm; Figure 14A Shown is a multilayer plasma or metamaterial device fabricated on chromium (Cr)-coated quartz; Figure 14B shows a gold/ITO film deposited on the Cr surface; Figure 14C shows ZEP520A (positron beam resist ) The film is spin-coated on top of the ITO/gold/Cr/quartz substrate, and a two-dimensional hole array is obtained on ZEP520A; Figure 14D shows the second layer of gold film coated on the electron beam patterning resist; and Figure 14E Shown is the removal of resist residues to form a two-dimensional gold disc array nanostructure; Figure 14F shows a scanning electron microscope (SEM) image of the two-dimensional gold disc array absorber metamaterial; Figures 15A to 15E show schematic diagrams of the flip chip transfer method. A three-layer absorber metamaterial with an area of 500μm times 500μm is transferred to a PET flexible substrate; Figure 15A shows the adhesion of a double-sided adhesive optically transparent adhesive 15B shows the three-layer metamaterial device in close contact with the optical adhesive, and is clamped between the rigid substrate and the optical adhesive; Figure 15C shows the quartz-based The Cr film on the material will be exposed to the air for several hours after the RF sputtering process, so that there is a thin native oxide film on the Cr surface; Figure 15D shows the three-layer metamaterial nanostructure from the Cr coated The quartz substrate is peeled off and transferred to the PET substrate; and Fig. 15E shows that the metamaterial nanostructure is covered by spin-coating the PMMA layer on the top of the device.

(從0至45度變化)是藉由PET基材的斜率與入射光的方向來界定； 圖20所示為用於Al₂O₃薄膜轉移的製造結構；圖21所示為Al₂O₃薄膜自施體基材剝離；圖22所示為犧牲銀層的蝕刻，以完成Al₂O₃薄膜轉移至PET基材；圖23所示為準備好用於薄膜轉移的Al₂O₃總成的製造樣本；圖24所示為Al₂O₃從施體基材分離；圖25所示為不同的退火後條件下在鈉鈣玻璃(soda lime glass，SLG)上的氧化鋁膜的奈米壓痕結果；圖26所示為沈積在藍寶石薄膜上方的摻雜氧化鋁層的樣本結構；圖27所示為以300℃退火的不同強化層的奈米壓痕測量；圖28所示為在室溫下，在SLG與ASS上的強化層為1：1(氧化鋁：氧化鎂)的奈米壓痕測量；圖29所示為以300℃退火的不同強化層的透射率；圖30所示為在室溫下，在SLG與ASS上的強化層為1：1(氧化鋁：氧化鎂)的透射率結果；圖31所示為在不同的退火溫度下，場矽石(field silica，FS)上的Al₂O₃：MgO為1：1的GID；圖32所示為不具有藍寶石膜、具有藍寶石膜與具有SiO₂藍寶石膜的被挑選出來的PMMA樣本的平均透射率；圖33所示為不具有藍寶石膜、具有藍寶石膜與具有SiO₂藍寶石膜的被挑選出來的PMMA樣本的平均硬度；圖34所示為具有最頂Al₂O₃ AR層的AR結構，也是抗刮層；圖35所示為具有折射率高於1.75的第二外側材料的AR結構； 圖36所示為在玻璃基材上具有TiO₂的AR結構；圖37所示為在玻璃基材上具有TiO₂的AR結構的透射模擬；圖38所示為在玻璃基材上具有ZrO₂的AR結構；圖39所示為在玻璃基材上具有ZrO₂的AR結構的透射模擬；圖40所示為在玻璃基材上具有HfO₂的AR結構；圖41所示為在玻璃基材上具有HfO₂的AR結構的透射模擬；圖42所示為在玻璃基材上具有GaN的AR結構；圖43所示為在玻璃基材上具有GaN的AR結構的透射模擬；圖44所示為在藍寶石基材上的AR結構；圖45所示為在藍寶石基材上的AR結構的透射模擬；圖46所示為在PMMA基材上的AR結構；圖47所示為在PMMA基材上的AR結構的透射模擬；圖48所示為在除了藍寶石以外的材料的基材上的三層AR結構；圖49所示為在藍寶石基材上的三層AR結構；圖50所示為在玻璃基材上的三層AR結構的透射模擬；圖51所示為在藍寶石基材上的三層AR結構的透射模擬；圖52所示為出自J.Lopez等人，設置在基材溫度150℃的折射率；圖53所示為在玻璃基材上具有TiO₂的第二外側材料的三層AR結構；圖54所示為具有增加的內側Al₂O₃厚度的三層AR的透射模擬；圖55所示為在藍寶石基材上具有SiO₂的三層AR結構； 圖56所示為在藍寶石基材上具有SiO₂的三層AR結構的透射模擬；圖57所示為在藍寶石基材上具有LiF的三層AR結構；圖58所示為在藍寶石基材上具有LiF的三層AR結構的透射模擬；圖59所示為在藍寶石基材上具有KCl的三層AR結構；圖60所示為在藍寶石基材上具有KCl的三層AR結構的透射模擬；圖61所示為在玻璃基材上的五層AR結構；圖62所示為在藍寶石基材上的六層AR結構；圖63所示為在玻璃基材上的五層AR結構的透射模擬；圖64所示為在藍寶石基材上的六層AR結構的透射模擬；圖65所示為在除了藍寶石以外的材料的基材上的一般AR組成物；圖66所示為在藍寶石基材上的一般AR組成物；圖67所示為在玻璃上的模擬與實驗AR結構的透射光譜；以及圖68所示為在玻璃基材上的五層AR結構的透射模擬。 Figures 16A and 16B show the flexible NIR absorber metamaterial on a transparent PET substrate; the area of each partition pattern is 500μm times 500μm; Figure 17 shows the absorber metamaterial on a quartz substrate (gold Disc/ITO/gold/chromium/quartz). NIR light is usually focused on the device and reflected signal and collected by a 15X objective lens. The blue line is the experimental result, and the red line is the simulated reflection spectrum using the RCWA method; Figure 18A shows the angle-resolved back reflection spectrum measured on a flexible metamaterial (with a curved surface). The incident light and back reflection from the PET side are collected by the NIR detector; Figure 18B shows the absorption in the flexible The transmission spectrum measured on the metamaterial, the light incident from the PMMA side is collected from the PET side; Figure 18C and Figure 18D are the simulated reflection and transmission spectra on the flexible absorber metamaterial using the RCWA method; Figure 19 shows Shown is an experimental diagram of measuring the reflectance spectrum of a metamaterial device under different bending conditions; the flexible substrate is bent by adjusting the distance between A and B, and the incident angle is 90°-

(From 0 to 45 degrees) is defined by the slope of the PET substrate and the direction of the incident light; Figure 20 shows the manufacturing structure for Al ₂ O ₃ film transfer; Figure 21 shows Al ₂ O ₃ The film is peeled from the donor substrate; Figure 22 shows the etching of the sacrificial silver layer to complete the transfer of the Al ₂ O ₃ film to the PET substrate; Figure 23 shows the manufacture of the Al ₂ O ₃ assembly ready for film transfer Sample; Figure 24 shows the separation of Al ₂ O ₃ from the donor substrate; Figure 25 shows the results of nanoindentation of alumina films on soda lime glass (SLG) under different annealing conditions; Figure 26 shows the sample structure of the doped aluminum oxide layer deposited on the sapphire film; Figure 27 shows the nanoindentation measurement of different strengthening layers annealed at 300°C; Figure 28 shows the sample structure at room temperature, The strengthening layer on SLG and ASS is 1:1 (aluminum oxide: magnesium oxide) nanoindentation measurement; Figure 29 shows the transmittance of different strengthening layers annealed at 300°C; Figure 30 shows the in-chamber At temperature, the transmittance results of the strengthening layer on SLG and ASS are 1:1 (aluminum oxide: magnesium oxide); Figure 31 shows the results of field silica (FS) at different annealing temperatures. Al ₂ O ₃ : MgO is 1:1 GID; Figure 32 shows the average transmittance of selected PMMA samples without sapphire film, with sapphire film and with SiO ₂ sapphire film; Figure 33 shows no The average hardness of selected PMMA samples with sapphire film, sapphire film and SiO ₂ sapphire film; Figure 34 shows the AR structure with the top Al ₂ O ₃ AR layer, which is also a scratch-resistant layer; Shown is an AR structure with a second outer material with a refractive index higher than 1.75; Figure 36 shows an AR structure with TiO ₂ on a glass substrate; Figure 37 shows an AR structure with TiO ₂ on a glass substrate Figure 38 shows the AR structure with ZrO ₂ on the glass substrate; Figure 39 shows the transmission simulation of the AR structure with ZrO ₂ on the glass substrate; Figure 40 shows the AR structure on the glass substrate AR having the structure of HfO _2; FIG analog transmission having AR structure of HfO ₂ on a glass substrate 41; FIG. 42 is a structure having AR of GaN on a glass substrate; FIG. 43 is shown in The transmission simulation of the AR structure with GaN on the glass substrate; Figure 44 shows the AR structure on the sapphire substrate; Figure 45 shows the transmission simulation of the AR structure on the sapphire substrate; Figure 46 shows the AR structure on PMMA substrate; Figure 47 shows the transmission simulation of the AR structure on PMMA substrate; Figure 48 shows the three-layer AR structure on the substrate of materials other than sapphire; Figure 49 shows Is a three-layer AR structure on a sapphire substrate; Figure 50 shows the transparency of a three-layer AR structure on a glass substrate Figure 51 shows the transmission simulation of the three-layer AR structure on the sapphire substrate; Figure 52 shows the refractive index from J. Lopez et al., set at the substrate temperature of 150 ℃; Figure 53 shows A three-layer AR structure with a second outer material of TiO ₂ on a glass substrate; Figure 54 shows a transmission simulation of a three-layer AR with an increased inner Al ₂ O ₃ thickness; Figure 55 shows a sapphire substrate A three-layer AR structure with SiO ₂ on it; Figure 56 shows a transmission simulation of a three-layer AR structure with SiO ₂ on a sapphire substrate; Figure 57 shows a three-layer AR structure with LiF on a sapphire substrate; Figure 58 shows the transmission simulation of the three-layer AR structure with LiF on the sapphire substrate; Figure 59 shows the three-layer AR structure with KCl on the sapphire substrate; Figure 60 shows the three-layer AR structure on the sapphire substrate Transmission simulation of a three-layer AR structure of KCl; Figure 61 shows a five-layer AR structure on a glass substrate; Figure 62 shows a six-layer AR structure on a sapphire substrate; Figure 63 shows a glass substrate The transmission simulation of the five-layer AR structure on the substrate; Figure 64 shows the transmission simulation of the six-layer AR structure on the sapphire substrate; Figure 65 shows the general AR composition on the substrate of materials other than sapphire Figure 66 shows the general AR composition on the sapphire substrate; Figure 67 shows the transmission spectra of the simulated and experimental AR structures on the glass; and Figure 68 shows the five-layer AR on the glass substrate Transmission simulation of the structure.

Figure 69A shows the hardness of two coated acrylonitrile butadiene styrene (ABS) samples, as shown in Figure 69B, they are significantly harder than uncoated ABS.

Figure 69B shows that at a displacement of 50 nm, the hardness of the two uncoated acrylonitrile butadiene styrene (ABS) samples is harder than the hardness of the uncoated PMMA substrate.

Figure 70 shows the hardness of coated and uncoated ABS with SLG as a reference.

Figure 71 shows the coated PI with and without the hardness of the buffer layer compared to other materials, namely coated SLG and bare PI (both sides). Coated PI is harder than bare PI, almost as hard as SLG.

Figure 72 shows the hardness of coated PC and PCPMMA (both sides) with doped Al ₂ O ₃ and PC with Al ₂ O ₃ (both sides). Quartz and fused silica (FS) are shown for reference.

Figure 73 shows the hardness of PMMA substrates coated with different Al ₂ O ₃ thicknesses.

Figure 74 shows the structure of a sapphire coated substrate on a flexible scratch-resistant multilayer coating.

The present invention is not limited to the scope of any specific embodiment described herein. The embodiments presented below are for illustration only.

Without wanting to be limited by theory, the present inventors have achieved the transfer of harder film substrates to softer flexible substrates (such as PET, polymers, plastics, etc.) through their experiments, experiments and research. Tasks on paper, even fabric). This combination is better than pure sapphire substrate. In the natural state, the harder the material, the more brittle. Therefore, the sapphire substrate is difficult to scratch, but it is easy to chip, and vice versa. The quartz substrate is easier to scratch, but the brittleness is less than that of the sapphire substrate. . Therefore, depositing a harder film substrate on a softer flexible substrate can do two things with one stone. Softer flexible substrates are less brittle, have good mechanical properties and are less costly. The anti-scratch function is achieved by using a harder film substrate. In order to harden the sapphire (Al ₂ O ₃ ) film deposition, the softening/melting temperature of the softer substrate should be high enough and higher than the annealing temperature. Most rigid substrates, such as quartz and fused silica, can meet this requirement. However, flexible substrates, such as polyethylene terephthalate (PET), cannot meet this requirement. The melting temperature of PET is about 250°C, which is much lower than the annealing temperature. PET is one of the most widely used flexible substrates. The ability to transfer Al ₂ O ₃ (sapphire) film substrates to softer flexible substrates will significantly expand its application range from rigid substrates (such as glass and metal) to flexible substrates (such as PET). , Polymers, plastics, paper, and even fabrics), and then the mechanical properties of the transferred substrate can be improved. Therefore, the Al ₂ O ₃ film is transferred from the rigid substrate to the flexible substrate, which can avoid the problem that the melting temperature of the flexible substrate is usually low.

According to a first aspect of the present invention, there is provided a method for coating/depositing/transferring a layer of a harder film substrate onto a softer substrate. Specifically, the present invention provides a method for depositing a sapphire film layer on a softer flexible substrate, such as PET, polymer, plastic, paper and fabric. This combination will be better than pure sapphire substrate.

According to a second aspect of the present invention, there is provided a method for coating sapphire (Al ₂ O ₃ ) on a flexible substrate, which includes: a first deposition procedure, depositing at least one first film on at least one first substrate To form at least one first film-coated substrate; in the second deposition process, at least one second film is deposited on the at least one first film-coated substrate to form at least one second film-coated substrate; third The deposition procedure is to deposit at least one catalyst on the at least one second film-coated substrate to form at least one catalyst-coated substrate; the fourth deposition procedure is to deposit at least one sapphire (Al ₂ O ₃ ) film on the at least one The catalyst is coated on the substrate to form at least one sapphire (Al ₂ O ₃ ) coated substrate; the annealing process, wherein the at least one sapphire (Al ₂ O ₃ ) coated substrate is at a temperature between 300° C. and lower than sapphire (Al ₂ O ₃ ) O ₃ ) annealed at the annealing temperature of the melting point and continued for an effective period to form at least one hardened sapphire (Al ₂ O ₃ ) film coated substrate; attach at least one flexible substrate to the at least one sapphire (Al ₂ O ₃ ) The at least one hardened sapphire (Al ₂ O ₃ ) film on the film is coated on the substrate; the mechanical separation procedure is to remove the at least one hardened sapphire (Al ₂ O ₃ ) film together with the at least one second film from the at least one The first thin film is separated from the coated substrate to form at least one second thin film coated and hardened sapphire (Al ₂ O ₃ ) thin film on the at least one flexible substrate; and an etching process to remove the at least one second thin film from the at least one The at least one second film on a flexible substrate is coated with a hardened sapphire (Al ₂ O ₃ ) film and removed to form at least one sapphire (Al ₂ O ₃ ) film to coat the flexible substrate.

According to the method of the present invention, wherein the first and/or the flexible substrate comprises at least one material, the Mohs hardness value of this material is lower than the Mohs hardness value of the at least one sapphire (Al ₂ O ₃ ) film.

In the method provided in the first embodiment of the second aspect of the present invention, the first and/or second and/or third and/or fourth deposition procedures include electron beam deposition and/or sputtering Deposition.

In the method provided in the second embodiment of the second aspect of the present invention, the at least one sapphire (Al ₂ O ₃ ) coated substrate and/or the at least one hardened sapphire (Al ₂ O ₃ ) coated substrate And/or at least one second film on the at least one flexible substrate is coated with a hardened sapphire (Al ₂ O ₃ ) film and/or at least one sapphire (Al ₂ O ₃ ) film is coated on the flexible substrate including at least one sapphire (Al ₂ O ₃ ) thin film.

In the method provided in the third embodiment of the second aspect of the present invention, the thickness of the at least one first substrate and/or the at least one flexible substrate is greater than the thickness of the at least one sapphire (Al ₂ O ₃ ) The thickness of the film is one or more orders of magnitude larger.

In the method provided in the fourth embodiment of the second aspect of the present invention, the thickness of the at least one sapphire (Al ₂ O ₃ ) film is about that of the at least one first substrate and/or the at least one flexible film. 1/1000 of the thickness of the base material.

In the method provided in the fifth embodiment of the second aspect of the present invention, the thickness of the at least one sapphire (Al ₂ O ₃ ) film is between 150 nm and 600 nm.

In the method provided in the sixth embodiment of the second aspect of the present invention, the valid period is not less than 30 minutes.

In the method provided in the seventh embodiment of the second aspect of the present invention, the valid period does not exceed 2 hours.

In the method provided in the eighth embodiment of the second aspect of the present invention, the annealing temperature range is between 850°C and 1300°C.

In the method provided in the ninth embodiment of the second aspect of the present invention, the annealing temperature range is between 1150°C and 1300°C.

In the method provided in the tenth embodiment of the second aspect of the present invention, the at least one material includes quartz, fused silica, silicon, glass, toughened glass, PET, polymer, plastic, paper, fabric Or any combination thereof; and, wherein the material used for the at least one flexible substrate cannot be etched by the at least one etching process.

The method provided in the eleventh embodiment of the second aspect of the present invention, wherein the adhesion between the at least one flexible substrate and the at least one hardened sapphire (Al ₂ O ₃ ) film Stronger than the bond between the at least one first film and the second film.

In the method provided in the twelfth embodiment of the second aspect of the present invention, the at least one first film includes chromium (Cr) or is between the at least one first film and the at least one second film Any material that forms a weak bond; wherein the material used for the at least one first thin film cannot be etched by the at least one etching process.

In the method provided in the thirteenth embodiment of the second aspect of the present invention, the at least one second film includes silver (Ag) or is between the at least one first film and the at least one second film Any material that forms a weaker bond; wherein the material used for the at least one second thin film cannot be etched by the at least one etching process.

In the method provided in the fourteenth embodiment of the second aspect of the present invention, the at least one catalyst includes a metal selected from titanium (Ti), chromium (Cr), nickel (Ni) , The group consisting of silicon (Si), silver (Ag), gold (Au), germanium (Ge), and a metal having a higher melting point than the at least one first substrate.

In the method provided in the fifteenth embodiment of the second aspect of the present invention, the at least one catalyst coated substrate includes at least one catalyst membrane; wherein, the at least one catalyst membrane is discontinuous; wherein, the The thickness of the at least one catalyst film is between 1 nm and 15 nm; and wherein, the at least one catalyst film includes nanodots with a diameter between 5 nm and 20 nm.

definition:

For clarity and completeness, the following is the definition of terms used in this disclosure.

The term "sapphire", when used here, refers to a material or substrate, and it is also known as a mineral corundum gem type with different impurities in this material or substrate, alumina ( alpha-Al ₂ O ₃ ) or alumina. Pure corundum (alumina) is colorless, or corundum with ~0.01% titanium. Due to the presence of different chemical impurities or trace elements, the various sapphire colors caused are:

●A typical blue sapphire has this color from trace amounts of iron and titanium (only 0.01%).

●The combination of iron and chromium produces yellow or orange sapphires.

●Only chromium will produce pink or red (ruby); at least 1% chromium will produce deep red ruby.

●Only iron produces light yellow or green.

●Violet or purple sapphire has this color because of vanadium.

The term "harder", when used here, refers to the relative value of the hardness of a material compared to another material. For more clarity, when the first material or substrate is defined as being harder than the second material or substrate, the Mohs hardness value of the first material or substrate is higher than the Mohs hardness of the second material or substrate value.

The term "softer", when used here, refers to the relative value of the hardness of a material compared to another material. For more clarity, when the first material or substrate is defined as softer than the second material or substrate, the Mohs hardness value of the first material or substrate is lower than the Mohs hardness of the second material or substrate value.

The term "flexible", when used here, means that the substrate can be physically manipulated using force to change the mechanical properties of its physical shape without breaking the substrate.

The term "screen", when used as a noun here, refers to the cover glass, cover screen, cover window, display screen, display window, cover surface or cover plate of the device. In order to be more clear, in many actual cases, the screen on a specific device has the dual function of displaying the device interface and protecting the surface of the device. For such cases, good light transmittance is a required feature of the screen; The lightness is not necessary, and in other cases where only the surface protection function is required, the light transmission of the screen is not necessary.

In one embodiment of the present invention, a method for developing a transparent screen is provided. The screen is harder and better than Gorilla Glass, comparable to a pure sapphire screen, but has the following advantages: ● Harder than any hardened glass; ● It is less likely to be brittle than a pure sapphire screen; ●weight is lighter than a pure sapphire screen; ●transparency is higher than a pure sapphire screen.

A method for depositing a sapphire film on a quartz substrate is provided in an embodiment of the present invention. By post-deposition processing, such as thermal annealing, an embodiment of the present invention has achieved a top surface hardness of up to 8-8.5 Mohs, which is close to the sapphire single crystal hardness of 9 Mohs. An embodiment of the invention is here It is "Sapphire Film on Quartz". Figure 2 shows the hardness of the top surface of the "sapphire film on quartz" compared to ordinary glass, gorilla glass, quartz and pure sapphire.

The quartz substrate itself is single crystal SiO ₂ , and its Mohs hardness value is higher than that of glass. In addition, its melting point is 1610°C, which can withstand the high temperature of annealing. In addition, the substrate can be cut to a desired size, and an embodiment of the present invention can then deposit a sapphire film on the substrate. The thickness of the deposited sapphire film is exactly 1/1000 of that of the quartz substrate. The cost of synthetic quartz crystal is relatively low (when the present invention is disclosed at this time, it is only less than US$10/kg). Therefore, compared with the production of pure sapphire substrates, the production cost and production time in an embodiment of the present invention are significantly reduced.

Features and benefits of an embodiment of the invention

Higher hardness than hardened glass

In an embodiment of the present invention, the developed sapphire film on quartz has a maximum hardness of 8.5 Mohs on the top surface. The hardness value of the new Gorilla Glass for smartphone screens is only about 6.5 Mohs, while the hardness value of the natural quartz substrate is 7 Mohs. Therefore, compared with the newly advanced technology, the present invention significantly improves the top surface hardness. The hardness value of the sapphire film on quartz is 8.5 Mohs, which is very close to the hardness value of pure sapphire 9 Mohs, and the sapphire film on quartz has the advantage of lower manufacturing cost and requires less manufacturing time.

Less cracked and lighter than sapphire

In the natural state, the harder the material, the more brittle it is. Therefore, the sapphire substrate is difficult to scratch, but it is easy to chip, and vice versa. Quartz has a relatively low modulus of elasticity, making it far more resistant to impact than sapphire.

In addition, in an embodiment of the present invention, the deposited sapphire film is very thin compared to the quartz substrate, and the thickness of the deposited sapphire film is only 1/1000 of that of the quartz substrate. Therefore, the overall weight of the sapphire film on quartz is almost the same as that of the quartz substrate, which is only 66.6% (or 2/3) of the weight of the pure sapphire substrate with the same thickness. This is because the density of quartz is only 2.65 g/cm ³ , the density of sapphire is 3.98 g/cm ³ , and the density of Gorilla Glass is 2.54 g/cm ³ . In other words, the quartz substrate is only 4.3% heavier than Gorilla Glass, but the pure sapphire substrate is about 1.5 times heavier than Gorilla Glass and Quartz. Table 1 shows the density comparison of quartz, Gorilla Glass and pure sapphire.

In a recently published patent application (US Patent Application No. 13/783,262, Apple), it is pointed out that it has created a way to fuse sapphire and glass layer to produce sapphire laminated glass to combine the durability of sapphire And the weight and flexibility of glass. However, polishing larger area (greater than 6 inches) and thin (less than 0.3 mm) sapphire substrates is quite challenging. Therefore, the use of sapphire film on quartz is the best combination for the screen to have a lighter weight, higher top surface hardness, and less cracked substrate.

Higher transparency than sapphire

Since the refractive indices of sapphire crystal, quartz crystal and Gorilla Glass are 1.76, 1.54 and 1.5 respectively, due to Fresnel's reflection loss, their overall transmittance is 85%, 91% and 92% . This means that there is a slight trade-off between transmittance and durability. Sapphire transmits less light, which can result in darker devices or shorter device battery life. When more light can be When transmitting, more energy will be saved and the battery life of the device will be longer. Figure 3 shows the transmittance of quartz, sapphire film on quartz and pure sapphire.

Most crystals, including sapphire and quartz, have birefringence problems. By comparing their normal ray and the abnormal ray refractive index (n ₀ and n _e), the difference value by the birefringence △ n is quantified. In addition, the value of Δn in an embodiment of the present invention is also relatively small, so that the birefringence problem in applications with a thinner substrate thickness (≦1 mm) is not serious. For example, pure sapphire is used as the cover lens of the iPhone 5S (iPhone 5S) camera, and it has not been disclosed that it will cause any blurry images. Table quartz and sapphire refractive index (n ₀ and n _e) for a normal ray and the abnormal ray with the difference value thereof birefringence △ n in FIG 2.

Shorter manufacturing time and lower manufacturing cost than pure sapphire

Recently, both synthetic sapphire and quartz single crystals have grown and are commercially available. Since the melting point of sapphire is higher than that of quartz, the growth of sapphire is more difficult and costly. More importantly, the growth time of sapphire is much longer than that of quartz. Growing sapphire for products larger than 6 inches is also challenging, and only a limited number of companies can do it. Therefore, the production volume is limited, making the production cost of the sapphire substrate higher than that of quartz. Table 3 shows the chemical formula, melting point and Mohs hardness value of quartz and sapphire.

Another challenge in the use of pure sapphire is that the hardness of the sapphire crystal is 9 Mohs, which is extremely difficult to cut and polish. So far, polishing large area (greater than 6 inches) and thin (less than 0.3 mm) sapphire substrates is still quite challenging. Although a larger number of sapphire crystal growth furnaces are currently in operation, the success rate is not very high, and this prevents the price of sapphire substrates from being reduced too much. Corning has claimed that the cost of a sapphire screen can be as much as 10 times that of Gorilla Glass. In contrast, quartz has a hardness value of 7 Mohs and it is easy to cut and polish. In addition, the cost of synthetic quartz crystals is relatively inexpensive (at the time of the disclosure of the present invention, the cost was only below US$10/kg).

Therefore, the additional cost of the sapphire film on quartz lies in the deposition of the sapphire film on the quartz substrate and the post-processing of the sapphire film on the quartz. In an embodiment of the present invention, when all conditions are optimized, the mass production process can be faster and lower in cost.

An embodiment of the present invention provides a method for depositing a harder sapphire film on a quartz substrate. The film thickness is in the range of 150nm-1000nm. By post-deposition treatment, such as thermal annealing at 500°C-1300°C, the embodiment of the present invention has reached a hardness of 8-8.5 Mohs, which is very close to the hardness of sapphire single crystal 9 Mohs. In another embodiment of the present invention, the sapphire film with a thickness of 150nm-500nm and a hardness of 8-8.5 Mohs is very close to the hardness of sapphire single crystal 9 Mohs, and it also has good optical properties with low scattering loss. The annealing temperature is from 1150 to 1300°C. Figure 4 shows the transmittance of a 190nm sapphire film on quartz and annealed at 1300°C for 2 hours and unannealed quartz. Therefore, in terms of hardness, the sapphire film on quartz is equivalent to a pure sapphire screen, and since the density of quartz is only 2.65g/cm ³ and the density of sapphire is 3.98g/cm ³ , its weight is almost the same as that of glass/quartz substrate Same, approximately 66.6% of the weight of the pure sapphire substrate. Since people can cut the substrate to a desired size according to the method of the present invention and can then deposit a sapphire film, the manufacturing cost and time will be significantly reduced compared to a pure sapphire substrate.

In fact, the hardness value of the sapphire film deposited by electron beam is not very high. In an embodiment of the present invention, the hardness value is measured to be lower than 7 Mohs. However, after the thermal annealing process, the film hardness will increase significantly. In an embodiment of the present invention, it is found that the sapphire film will soften when annealed at 1300°C for 2 hours. The film thickness shrinks by about 10%, and the film hardness increases to 8-8.5 Mohs. Because the quartz substrate is single crystal SiO ₂ with a melting point of 1610°C, it can withstand the high temperature of annealing. Therefore, the hardness of the annealed sapphire film on the quartz substrate can reach 8.5 Mohs. Figure 4 shows the transmittance of a 190nm thick sapphire film on quartz and annealed at 1300°C for 2 hours and unannealed quartz.

In addition, in other embodiments of the present invention, the annealing process of the sapphire film may be performed on other substrates. For example, a sapphire film annealed at 1000°C on a fused silica substrate, and a sapphire film annealed at 500°C on a glass substrate.

Electron beam (E-beam) and sputtering deposition are the two most common methods for depositing sapphire films on quartz and other related substrates. These two common deposition methods are used in some embodiments of the present invention.

Sapphire film deposited by electron beam

The outline of electron beam deposition to deposit sapphire film on a specific substrate is as follows:

●Since alumina has a very high melting point of 2040°C, the deposition of sapphire thin films uses electron beam evaporation. The white particles or colorless crystals in the small-sized pure alumina are used as the source of electron beam evaporation. The high melting point alumina also allows the annealing temperature to reach below the melting point of sapphire (for example, 2040°C under atmospheric pressure).

●The substrate is vertically stuck on the sample holder 450mm away from the evaporation source. When deposition occurs, the sample holder is rotated at 1-2 RPM.

●The basic vacuum of the evaporation chamber is less than 5x10 ^-6 Torr, and when deposition occurs, the vacuum is kept below 1x10 ^-5 Torr.

●The thickness of the film deposited on the substrate is about 150nm to 1000nm. The deposition rate is about 1-5Å/s. The substrate is not externally cooled or heated during deposition. The film thickness is measured by the ellipsometry method and/or scanning electron microscope (SEM).

●Higher temperature film deposition from room temperature to 1000°C is possible.

The process of depositing a sapphire film on another substrate by electron beam is described in more detail as follows:

1) Since aluminum oxide has an extremely high melting point of 2040°C, the deposition of sapphire thin films uses electron beam evaporation. Alumina particles are used as the source of evaporation. The high melting point alumina also allows the annealing temperature to reach below the melting point of sapphire (for example, 2040°C under atmospheric pressure).

2) The coated substrate is vertically stuck on the sample holder 450mm away from the evaporation source. When deposition occurs, the sample holder is rotated at 2RPM.

3) The thickness of the film deposited on the substrate is about 190 nm to 1000 nm. The deposition rate is about 1Å/s. The substrate is not externally cooled or heated during deposition. The film thickness is measured by ellipsometry.

4) After the sapphire film is deposited on the substrate, it is annealed in a furnace at 500°C to 1300°C. The temperature rise rate is 5°C/min, and the drop rate is 1°C/min. The time ranges from 30 minutes to 2 hours and is maintained at a specific thermal annealing temperature.

5) The deposition substrate includes quartz, fused silica and (toughened) glass. Their melting points are 1610°C, 1140°C, and 550°C, respectively, and the annealing temperature of the sapphire film coated on them is 1300°C, 1000°C, and 500°C, respectively.

6) The transmittance of 190nm sapphire film on quartz and 190nm sapphire film annealed at 1300°C for 2 hours and unannealed quartz is shown in FIG. 4. The transmittance percentage in the entire visible light region of 400nm-700nm is greater than 86.7%, and the maximum is 91.5% at 550nm, while the transmittance percentage of the pure sapphire substrate is only 85-86%. The more light is transmitted, it means that the backlight of the display panel saves more energy, so the battery life of the device will be longer.

Annealing procedure of an embodiment of the present invention

After the sapphire film is deposited on the substrate, it is annealed in a furnace at 500°C to 1300°C. The temperature rise rate is 5°C/min, and the drop rate is 1°C/min. The annealing time ranges from 30 minutes to 2 hours and is kept at a specific thermal annealing temperature. Within the above range, multiple steps of annealing at different temperatures are also used to enhance the hardness and also reduce the micro-crack of the film. Table 4 shows the surface hardness and XRD characteristic peaks prepared by electron beam deposition at different annealing temperatures. This table also shows the various sapphire crystal phases present in the film; the most common phases are α, θ, and δ.

Table 4 shows that the surface hardness of the sapphire film changes with the annealing temperature ranging from 500°C to 1300°C. In fact, the initial hardness value of the unannealed electron beam deposited sapphire film is about 5.5 Mohs. However, after the thermal annealing process, the film hardness will be significantly improved. By using annealing temperatures in the range of 500℃-850℃, 850℃-1150℃ and 1150℃-1300℃, the hardness values of the sapphire film on quartz are 6-7 Mohs and 7-8 respectively in the hardness scale. Mohs and 8-8.5 Mohs.

Figure 5 shows the XRD results of a 400nm sapphire film on quartz annealed at 750°C, 850°C and 1200°C for 2 hours. When the annealing temperature is greater than 850°C, the film will begin to partially crystallize. The appearance of new XRD peaks will correspond to the mixing of alumina θ and δ structure phases.

When the annealing temperature is above 1300°C, the film will begin to develop some larger grains, which can obviously scatter visible light, which will reduce the transmission intensity. In addition, as these larger crystal grains accumulate more and more, the film will break and some tiny fragments will separate from the substrate.

In an embodiment of the present invention, the sapphire film on the quartz substrate is found to be annealed at 1150°C to 1300°C for half an hour to two hours. The film thickness will shrink by about 10%, and the film hardness will increase to 8-8.5 Mohs. Since the quartz substrate is a single crystal SiO ₂ with a melting point of 1610°C, it can withstand such a high annealing temperature. At this annealing temperature, the hardness of the annealed sapphire film on the quartz substrate has reached 8.5 Mohs.

As shown in Fig. 6, it is the transmittance of 400nm sapphire film on quartz and sapphire substrates annealed at 1200°C for 2 hours and unannealed quartz. The transmittance of the sapphire film on quartz in the visible light region of 400-700nm is greater than 88%, and the maximum value is 92% at 550nm. The interference pattern is due to the difference between the refractive index of the material and the thickness of the film. The overall average transmittance is about 90%, while the pure sapphire substrate is only 85-86%. In addition, at certain wavelengths, the light transmission spectrum of the sapphire film on quartz is consistent with that of the quartz substrate, which indicates excellent optical performance and low scattering loss. Maximum intensity and minimum intensity of interference pattern The difference between the degrees is only about 4%. For practical applications, the more light is transmitted, the more energy can be saved by the backlight of the display panel, and therefore the longer the battery life of the device is.

Thickness of sapphire film on quartz

Sapphire films on quartz with thicknesses in the range of 150nm-1000nm have been tested. In an embodiment of the present invention, when the annealing temperature is 1150° C. to 1300° C., a sapphire film with a thickness of 150 nm-500 nm with good optical properties and low scattering loss is provided. However, when the thickness is greater than 600 nm, the film may be broken, causing significant scattering, which may reduce the transmission intensity.

For the sapphire film deposited on quartz with a thickness of 150nm-500nm and annealed at 1150℃ to 1300℃, the measured hardness can reach 8-8.5 Mohs in the Mohs hardness scale, which means even thinner The coating film can also be used as a scratch-resistant layer.

Other substrates that may be used for scratch-resistant coating

In addition to quartz substrates, other embodiments of the present invention have also studied the deposition of sapphire films on different substrates (such as fused silica and silicon). Other tempered glass or transparent ceramic substrates with higher annealing or melting temperature, which can withstand the annealing temperature of 850°C within 30 minutes to 2 hours, may also be used as a scale to enhance the surface hardness to Mohs hardness 7-8 Mohs base material. For example, Schott Nextrema transparent ceramics have a short heating temperature at 925°C; Corning Gorilla Glass has a softening temperature of 850°C.

Since the annealing temperature of fused silica is about 1160°C, it is a good candidate for starting to study the suitability of its substrate. However, compared to the sapphire film on quartz annealed at 850°C to 1150°C, the sapphire film on fused silica exhibits a different behavior even though they are deposited under the same deposition conditions. The adhesion of the sapphire film on the fused silica is not as good as that on the quartz (due to the significant difference in the coefficient of expansion), and local peeling of the film and micro-size cracks will appear on the fused silica substrate. However, the use of a thinner film will substantially alleviate these problems that can cause light scattering. Figure 7 shows the transmittance of a 160nm sapphire film annealed at 1150°C for 2 hours and on unannealed fused silica. The transmittance of the sapphire film on fused silica in the entire visible light region of 400nm-700nm is greater than 88.5%, and reaches a maximum of 91.5% at 470nm. The overall average transmittance percentage is about 90%, while the pure sapphire substrate is only 85%-86%. In addition, the measured surface hardness is maintained above 8 Mohs on the Mohs hardness scale.

Silicon with a melting temperature of about 1410°C is an opaque substrate material. Under the same deposition conditions, compared to the quartz substrate, the sapphire film on the silicon substrate shows similar characteristics in the Mohs hardness, and they are also divided into two temperature ranges. However, because silicon is not a transparent substrate, it cannot be applied to transparent cover glass or windows. Therefore, the sapphire film can only provide scratch resistance, as a protective layer to protect the silicon surface from scratches (the Mohs hardness of silicon is 7 Mohs). This type of protective layer can potentially eliminate thick glass encapsulation, which increases light absorption and therefore increases light collection efficiency. Other solar cells based on inorganic semiconductors that can withstand high-temperature processing can also have similar sapphire film deposition on them. Through the embodiments of the present invention described here, it is conceivable that those skilled in the art should be able to fully apply the present invention to deposit a sapphire film on other substrates, so that the sapphire film can be used as the scratch resistance of the underlying substrate. Protective layer, and these substrates can withstand the duration of the annealing temperature of the present invention.

Annealed sapphire film deposited by sputtering

Sapphire film deposited by sputtering

The steps for depositing a sapphire film on a specific substrate by sputtering deposition are provided as follows:

1) The deposition of the sapphire film can be carried out by sputtering deposition with aluminum or alumina as the target.

2) These substrates are attached to the sample holder about 95 mm from the target. When deposition occurs, the sample holder is rotated to achieve thickness consistency, for example, at 10 RPM.

3) The basic vacuum of the evaporation chamber is lower than 3x10 ^-6 mbar, and the coating pressure is about 3x10 ^-3 mbar.

4) The thickness of the film deposited on the substrate is about 150 nm to 600 nm.

5) Film deposition at higher temperatures from room temperature to 500°C is possible.

Annealing procedure of another embodiment of the present invention

After the sapphire film is deposited on the substrate, they are annealed in a furnace at a temperature varying between 500°C and 1300°C. The temperature rise rate is 5°C/min and the drop rate is 1°C/min. The time ranges from 30 minutes to 2 hours while maintaining at a specific thermal annealing temperature. The multiple steps of annealing at different temperatures are also used to enhance the hardness and also reduce the microcracks of the film. This is shown in Table 5.

Table 5 shows the change in the surface hardness of the sapphire film on quartz with the annealing temperature varying between 500°C and 1300°C. In fact, the initial hardness value of the sapphire film deposited by sputtering and not annealing is slightly higher than that of the sapphire film deposited by electron beam, about 6-6.5 Mohs. After the thermal annealing process, the hardness of the film is different from that of the film deposited by electron beam. When the annealing temperature is in the range of 500°C-850°C, the film hardness has no significant change. In the range of 850℃-1150℃, the film coated on quartz is easy to peel off. However, in the range of 1150℃-1300℃, the film forms a hard film; when the thickness is 150nm-300nm, the surface hardness is 8-8.5 Mohs, and when the thickness is 300nm-500nm, the surface hardness is 8.5-8.8 Mohs.

Figure 8A shows the XRD results of a 400nm sapphire film on quartz annealed at 850°C, 1050°C and 1200°C for 2 hours. The XRD peaks that appear correspond to the mixing of the delta, theta and alpha structural phases of alumina. Unlike electron beam evaporation, in the XRD results of sputtering deposition, the presence of the alpha phase of alumina leads to a harder surface or higher surface hardness, with an average of 8.7 Mohs. Figure 8B shows the XRD results of sapphire films with thicknesses of 220 nm, 400 nm and 470 nm on quartz annealed at 1150°C for 2 hours. The appearance of the α phase starts from the thickness of about 300 nm, and when the thickness of the sapphire film increases to 470 nm, the original mixed structure phase almost transforms into the α phase. Under this condition, the surface hardness is the highest. However, further increasing the thickness of the sapphire film will cause the film to peel off.

As shown in FIG. 9, it is the light transmission spectra of 220nm, 400nm, and 470nm sapphire thin films on quartz prepared by sputter deposition and annealed at 1100°C for 2 hours compared to the quartz substrate. Regarding the annealed 220nm sapphire film on quartz, its optical properties are excellent and there is only a small amount of scattering loss. The transmittance in the entire visible light region of 400nm-700nm is greater than 87%, and reaches a maximum of 91.5% at 520nm. The overall average transmittance is about 90.2%. The difference between the maximum intensity and the minimum intensity of the interference pattern is only about 4.5%.

However, when the thickness of the sapphire film is greater than 300 nm, the light transmission intensity begins to decrease, especially in the UV range, which means that Rayleigh scattering begins to take the lead. The strong wavelength dependence of Rayleigh scattering is suitable for scattering particles with a particle size of less than 1/10 wavelength, which is due to the The formation of alpha phase in sapphire film with crystal size less than 100nm. Therefore, the surface hardness will become higher, but the transmittance will become worse.

For 400nm and 470nm sapphire films annealed on quartz, the transmittance percentages in the entire 400nm-700nm visible light region are within 81%-88% and 78%-87%, respectively. Their overall average transmittance values are approximately 85.7% and 83.0%, respectively.

However, when the thickness of the sapphire film is greater than 500 nm, the larger crystal grains will accumulate with microcracks, the film will be broken, and some tiny flakes will be separated from the substrate.

Sapphire film on fused silica deposited by sputtering

In addition to quartz substrates, since the annealing temperature of fused silica is about 1160°C, low-cost fused silica is a potential candidate for sapphire film-coated substrates.

Table 6 shows the surface hardness of the sapphire film on fused silica with the annealing temperature varying between 750°C and 1150°C. In fact, the initial hardness value of the sapphire film on sputtered and unannealed fused silica is slightly lower than the initial hardness value of the sapphire film on quartz, which is about 5.5-6 Mohs. In the range of 850°C to 1150°C, the hardness of all 150nm-600nm thick sapphire films is even worse, below 5 Mohs. However, at 1150°C, the film can form a hard film again, and for all sapphire films of 150nm-600nm, the surface hardness is 8-8.5.

Figure 10 shows the XRD results of a 350nm thick sapphire film on fused silica prepared by sputtering and annealing at 750°C, 850°C, 1050°C and 1150°C for 2 hours. XRD results show that the mixture of theta and alpha structural phases of alumina coexist on the fused silica substrate. Therefore, the sapphire film has a hard surface of 8-8.5 Mohs, while the fused silica substrate has only 5.3-6.5 Mohs.

Compared with the fused silica substrate, the transmission spectrum of the 180nm-600nm thick sapphire film on the fused silica prepared by sputtering deposition and annealing at 1150°C for 2 hours is shown in FIG. 11.

For 180nm and 250nm thick sapphire films annealed on fused silica, the optical properties are excellent and there is only some scattering loss. The transmittance of the sapphire film is between 88.9%-93.1% and 84.8%-92.8% in the entire 400-700nm visible light region. Their overall average transmittance values are about 91.3% and 90.7%, respectively.

For 340nm and 600nm thick sapphire films annealed on fused silica, the transmittance across the 400nm-700nm visible region is between 75%-86% and 64%-80%, respectively. Their overall average transmittance is about 81.7% and 74.1%, respectively.

Therefore, the sapphire film on fused silica annealed at 1150°C with a thickness of 150nm-300nm has good optical properties and a transmittance of approximately 91%, and also has a hard surface hardness greater than 8 Mohs.

Low temperature annealing program

The commonly used "toughened" screen material is Corning's Gorilla Glass, which has been used on more than 1.5 billion devices. On the Mohs hardness scale, the Mohs hardness of the latest Gorilla Glass is only 6.5-6.8, which is lower than the Mohs hardness of mineral quartz. As a result, Gorilla Glass is still easily scratched by sand. Therefore, another method is to deposit a harder film on a glass substrate. However, for most commonly used cover glasses, the maximum allowable annealing temperature is in the range of 600°C to 700°C. In this temperature range, the hardness of the previously annealed sapphire film can only reach 6-7 Mohs, which is close to the hardness of the glass substrate itself. Therefore, a new technology using annealing temperatures below 700°C was developed to promote the Mohs hardness of the annealed sapphire film to exceed 7.

In another embodiment of the present invention, one or more layers of higher hardness sapphire film are deposited on a lower hardness substrate (for example, Gorilla glass, toughened glass, soda lime glass, etc.), and the maximum allowable annealing temperature Below 850°C. Therefore, a harder scratch-resistant film can be coated on the glass. This is the fastest and lower cost way to improve their surface hardness.

In yet another embodiment of the present invention, by using nano-layers of metals such as Ti and Ag, it shows that the polycrystalline sapphire film can be grown at a lower temperature. This catalytic enhancement can be induced at temperatures significantly lower than when the nanometal catalyst is not used. This enhancement comes from the crystallization that will begin once there is enough kinetic energy to allow the deposition of atoms to gather, and the annealing temperature can start at 300°C. The low temperature annealing of the present invention starting at 300°C is shown in Table 7.

Figure 13A shows the X-ray reflectance (XRR) measurement results of different samples under different annealing conditions in each embodiment of Table 7, and Figure 13B shows the measurement results of different samples in each embodiment of Table 7. Optical transmission spectra under different annealing conditions.

In one embodiment, a method developed is to deposit a very thin "discontinuous" metal catalyst and a thicker sapphire film on a glass substrate. By post-deposition treatment, such as thermal annealing at 600-700°C, a hardness of 7-7.5 Mohs can be achieved, which is higher than that of most glasses.

The nanometal catalyst deposited by a deposition system (such as electron beam evaporation or spraying) should have a thickness of 1-15 nm. This catalyst is not a continuous membrane, as shown by SEM. The deposited metal may have a nano-dot (ND) shape with a diameter of 5-20 nm. The metal includes titanium (Ti) and silver (Ag). Thicker sapphire films will be in the range of 100-1000nm.

In fact, the hardness value of the sapphire film deposited by electron beam or sputtering is not too high, only about 5.5-6 Mohs. However, after the thermal annealing process, the film hardness will increase significantly. Mi Jin In the case of a catalyst, the film hardness annealed at an annealing temperature of 600-850°C is about 6-7 Mohs. After adding a nanometal catalyst, the hardness of the film annealed at an annealing temperature of 600-700°C will increase to 7-7.5 Mohs, and annealed at an annealing temperature of 701-1300°C will reach a hardness of 8.5 to 9 Mohs.

This is a significant improvement in the surface hardness of the glass substrate, especially its annealing temperature is lower than the softening temperature of the glass. This means that the glass will not deform during annealing. Therefore, the role of the metal catalyst is not only to enhance the adhesion between the sapphire film and the glass substrate, but also to induce the hardening of the sapphire film. The surface hardness of sapphire films prepared by electron beam deposition and at different annealing temperature ranges with and without nanometal catalysts are shown in Table 8.

The outline of depositing sapphire film on glass substrate by electron beam deposition is as follows:

1) The basic vacuum of the evaporation chamber is lower than 5x10 ^-6 Torr, and when deposition occurs, the deposition vacuum is kept below 1x10 ^-5 Torr.

2) The substrate is attached to the sample holder at a distance from the evaporation source, for example, the distance is 450 mm. When depositing, the sample holder rotates at 1-2 RPM.

3) The deposition of nano metals with higher melting points (such as Ti, Cr, Ni, Si, Ag, Au, Ge, etc.) uses deposition systems (such as electron beam evaporation and sputtering). The thickness of the metal catalyst directly deposited on the substrate is about 1-15 nm as monitored by the QCM sensor. The deposition rate of nanometal catalyst is about 0.1Å/s. The substrate is not externally cooled or heated during deposition. The morphology of the film is measured by SEM top view and cross-sectional view.

4) The deposition of the sapphire film uses electron beam evaporation, because it has an extremely high melting point of 2040°C. Small-size white particles or colorless crystals of pure alumina are used as electron beam evaporation sources. High melting point alumina can also make the annealing temperature reach below the melting point of sapphire (for example, 2040°C under atmospheric pressure).

5) The thickness of the sapphire film deposited on the substrate is about 100 nm to 1000 nm, and the deposition rate is about 1-5 Å/s. The substrate is at room temperature during deposition, and the active temperature is not necessary. The film thickness can be measured by ellipsometry or other suitable methods with similar or better accuracy.

6) After the sapphire films are deposited on the substrate, they are annealed in a furnace at a temperature varying between 500°C and 1300°C. The temperature rise gradient should be gradual, such as 5°C/min, and the drop gradient should also be gradual, such as 1-5°C/min. Within the specific thermal annealing temperature range, the annealing time is between 30 minutes and 10 hours. Multiple annealing steps at different temperatures within the above range can also be used to enhance the hardness and reduce the microcracks of the film.

The transmittances of fused silica and 250nm annealed sapphire film on fused silica with or without 10nm titanium catalyst and annealed at 700°C and 1150°C for 2 hours are shown in FIG. 12. For the annealing results at 700°C, the average transmittance percentage in the visible light region of 400-700nm is greater than 89.5%, and reaches a maximum of 93.5% at 462nm, while the average transmittance of the fused silica substrate is 93.5%.

Film transfer procedure

In another embodiment of the present invention, a method and device for manufacturing a multilayer flexible metamaterial is provided, which uses flip chip transfer (FCT) technology. Such metamaterials include harder film substrates that are transferred to softer flexible substrates. This technology is different from other similar technologies, such as the metal stripping process or nano-printing technology in which nanostructures are directly fabricated on flexible substrates. It is a solution-free FCT technology that uses a double-sided optical adhesive as an intermediate transfer layer, and the three-layer metamaterial nanostructure on a rigid substrate can be transferred to the adhesive first. Another embodiment of the present invention is such a manufacturing method and equipment, which enables metamaterials to be transferred from rigid substrates such as glass, quartz, and metals to flexible substrates such as plastic or polymer films. Therefore, flexible metamaterials can be manufactured independently of the original substrate used.

Device manufacturing

The schematic manufacturing process of the multilayer metamaterial is shown in FIG. 14. First, using the existing EBL process, a multilayer plasma or metamaterial device is manufactured on chromium (Cr) coated quartz. The 30nm thick Cr layer serves as a sacrificial layer. Then, using thermal evaporation and RF sputtering methods, respectively, a gold/ITO (50nm/50nm) film was deposited on the Cr surface. Next, a ZEP520A (positron beam resist) film with a thickness of about 300 nm was spin-coated on top of the ITO/gold/Cr/quartz substrate, and a two-dimensional hole array was obtained on the ZEP520A using EBL processing. To obtain the gold nanostructure (disc pattern), a second layer of 50nm thick gold film was coated on the electron beam patterning resist. Finally, the resist residue is removed to form a two-dimensional gold disk array nanostructure. The area of each metamaterial pattern is 500 μm by 500 μm, the period of the disk array is 600 nm, and the diameter of the disk is ~365 nm.

Flip Chip Transfer (FCT) Technology

The transfer process of the flexible absorber metamaterial is shown in Figure 15. A double-sided viscous optically transparent adhesive (50 μm thick, such as a commercial product manufactured by 3M) is attached to a PET substrate (70 μm thick). Therefore, the three-layer metamaterial device is in close contact with the optical adhesive, and is clamped on the rigid substrate for the optical adhesive Between agents. It should be noted that the Cr film on the quartz substrate will be exposed to the air for several hours after the RF sputtering process, resulting in a thin native oxide film on the Cr surface. Therefore, compared to the gold/ITO/gold disc/optical adhesive area, the surface adhesion between Cr and gold will be much weaker. This allows the three-layer metamaterial nanostructure to be peeled from the Cr-coated quartz substrate. Once the metamaterial nanostructure is transferred to the PET substrate, it will have enough flexibility to bend into various shapes. Finally, by spin-coating a 300nm thick PMMA layer on top of the device, the metamaterial nanostructure will be coated.

In another embodiment, the present invention provides a novel NIR metamaterial device that can be transformed into various shapes by bending the PET substrate.

Figure 16(a) shows a flexible absorbent metamaterial sandwiched by transparent PET and PMMA films. Several nanostructures of absorber metamaterials with an area of 500μm by 500μm were fabricated on a flexible substrate. In fact, using the flexible properties of the PET layer, the absorbent metamaterial device can conform to many shapes, such as cylindrical (Figure 16(b)). The minimum radius of the cylindrical substrate is about 3mm. After 10 repeated bending tests, no obvious defects are observed on the metamaterial device.

Optical properties and simulation

The three-layer metal/dielectric nanostructure described above is an absorber metamaterial device. The design of the device makes the incident light energy tightly concentrated in the ITO layer. The absorption effect of the NIR three-layer metamaterial architecture can be explained as local surface plasmon resonance or magnetic resonance. The absorption phenomenon mentioned here is different from the transmission suppression in the metal disc array, in which the incident light will be largely absorbed due to the abnormal resonance of the ultra-thin metal nanostructure. In order to characterize the optical characteristics of the gold disc/ITO/gold absorber metamaterial, Fourier transform infrared spectrometer (FTIR) is used to measure the reflectance spectrum of the absorber metamaterial. By combining an infrared microscope and an FTIR spectrometer, the transmission and reflection spectra of the nanophotonic device in the micro-area can be measured. In Figure 17, the reflectance spectrum from the air/metamaterial interface (experimental Line graph) is measured with a sampling area of 100μm by 100μm. At the absorption peak with a wavelength of about 1690nm, the reflection efficiency is about 14%, that is, the absorber metamaterial works at this wavelength. In the RCWA simulation (simulated line drawing), the physical optical constants of E.D. Palik, Handbook of optical constants of solids, Academic Press, New York, 1985 will be used; the content is incorporated herein by reference in its entirety. At the resonance wavelength, the experiment and calculation agree with each other.

The reflection spectrum of the flexible absorber metamaterial is shown in Fig. 18(a) (0° line graph). Compared with the FTIR results shown in Figure 17, the absorption drop of the flexible metamaterial has been redshifted to about 1.81μm. This red shift is mainly due to the change in refractive index of the surrounding medium (the refractive index of the optical adhesive and PET is about 1.44). In Figure 18(c) and Figure 18(d), the three-dimensional rigorously coupled wave analysis (RCWA) method is used to calculate the reflection and transmission spectra on the absorber metamaterial, and gold, ITO, Cr, SiO ₂ and Experimentally verified parameters of PET materials. In theoretical simulations, resonance absorption at a wavelength of about 1.81μm can also be observed. However, in the measured reflectance spectrum, there are two resonance drops of about 1.2 μm. In the RCWA calculation (Figure 18(c)), the double descent is reproduced and can be attributed to the two local resonance modes because they are not very sensitive to the angle of incidence. For the calculation of angular dependence, TE polarized light (electric field perpendicular to the plane of incidence) is used to fit the experimental results. When the incident angle changes from 0 degrees to 45 degrees, the reflection efficiency shows an increasing trend because the light cannot be effectively concentrated under a large angle of incidence. However, the back reflection efficiency in the experiment (Figure 18(a)) was significantly reduced. This is because the current experimental setup (described in the next paragraph) only allows the collection of back reflection signals (incident and collection directions are the same as each other), and The collection efficiency for large incident angles is very low. In Figure 18(b), the transmission spectrum of the flexible metamaterial is measured using the same FTIR configuration. The main difference is the incidence of light from the air/PMMA interface. The Fano-type transmission peak is observed at a wavelength of about 1.85 μm. At the resonance wavelength, the experimental transmission efficiency is higher than the theoretical simulation (Figure 18(d)). This can be attributed to the defects on the gold plane film and the two-dimensional disk array, which enhance the efficiency of leaking radiation and thus result in a higher transmission efficiency in the measurement results.

)是由超材料裝置位置處的彎曲斜率來決定。如圖18(a)，當入射角由0度增加至45度時，可以觀察到背反射的強度變得較弱且吸收下降變得較淺。儘管如此，其可顯示出撓性吸收體超材料的共振吸收波長對光的入射角並不敏感。超材料製成的裝置可製成非常靈敏的感測器。本發明提供一種在撓性基材上製造超材料裝置的新穎技術，撓性讓此裝置可彎曲與拉伸，並改變此裝置結構。由於每一裝置的共振頻率為裝置結構的一種功能，因而共振頻率可藉由基材的彎曲與拉伸來微調。因此，本發明的另一個實施例為一種超材料，其允許以物理方式改變材料的結構，這會導致其自身共振頻率的變化，且無需改變材料組成。如此，本發明之超材料的一實施例是一種撓性電漿子或超材料奈米結構裝置，其可作為電磁波吸收體。 As shown in Figure 19, the curved PET substrate allows the absorber metamaterial to measure the optical response under different curved shapes. The shape of the curved PET substrate is controlled by adjusting the distance between the ends of the substrate (A and B), and the angle of the analytical back reflection on the absorber device is measured by changing the bending conditions. As shown in Figure 19, the incident angle (90°-

) Is determined by the bending slope at the location of the metamaterial device. As shown in Figure 18(a), when the incident angle is increased from 0 degrees to 45 degrees, it can be observed that the intensity of back reflection becomes weaker and the absorption drop becomes shallower. Nevertheless, it can be shown that the resonance absorption wavelength of the flexible absorber metamaterial is not sensitive to the incident angle of light. Devices made of metamaterials can be made into very sensitive sensors. The present invention provides a novel technology for manufacturing a metamaterial device on a flexible substrate. The flexibility allows the device to bend and stretch, and to change the structure of the device. Since the resonance frequency of each device is a function of the device structure, the resonance frequency can be fine-tuned by bending and stretching of the substrate. Therefore, another embodiment of the present invention is a metamaterial, which allows the structure of the material to be changed in a physical manner, which causes a change in its own resonance frequency without changing the material composition. Thus, an embodiment of the metamaterial of the present invention is a flexible plasma or metamaterial nanostructure device, which can be used as an electromagnetic wave absorber.

According to the above-mentioned embodiments of the present invention, a three-layer absorber metamaterial device that operates at NIR wavelengths and has high flexibility can be realized. Using the FCT method, the three-layer gold disc/ITO/gold absorber metamaterial is transferred from the quartz substrate to the transparent PET substrate with an optically transparent adhesive (such as a commercial product manufactured by 3M). In addition, the three-layer absorber metamaterial is covered with a PMMA film and an optical adhesive layer to form a flexible device. FTIR experiments have shown that the absorber metamaterial works well on quartz substrates and on highly flexible PET substrates. On this flexible metamaterial, it can be observed that the angle-insensitive absorption effect resonates with Fano-type transmission.

Moreover, the solution-free FCT technology described in the present invention can also be used to transfer other visible light-NIR metal/dielectric multilayer metamaterials to flexible substrates. Flexible metamaterials acting under the visible light-NIR system have many advantages in manipulating light in three-dimensional space, especially when the metamaterial structure is designed on a curved surface. In another embodiment of the present invention, the FCT technology of the present invention can be used to transfer a hardened film to a softer flexible substrate.

Experimental details of transferring films to flexible substrates

A method used to transfer Al ₂ O ₃ film from a rigid substrate to a PET substrate, which uses a metal intermediate layer with weak adhesion. This method is based on the referenced US non-provisional patent application filed on December 23, 2012, application number 13/726,127 and the US non-provisional patent application filed on December 23, 2012, application number 13/726,183. Both claim the priority of the US provisional patent application filed on December 23, 2011, application number 61/579,668. An embodiment of the present invention uses a transparent polyester tape and applies mechanical stress to completely separate the Al ₂ O ₃ film from the sacrificial metal layer. Then, the Al ₂ O ₃ film is transferred to the PET substrate, and the sacrificial metal layer can be removed by acid etching.

First, a thin (ie 30-100nm thick) chromium (Cr) film is deposited on the fused silica substrate, and then a thin (ie 30-100nm thick) silver (Ag) film is deposited on top of the Cr. Next, another metal layer, such as a Ti film (3-10 nm thick), is deposited and used for the annealing process. Next, a thin film of Al ₂ O ₃ (for example, 100-500 nm) is deposited on the metal layer. Next, as in each embodiment of the low-temperature annealing procedure of the present invention described above, annealing is performed in a temperature range of 300°C to 800°C. The flexible transparent polyester tape with an optical transmittance higher than 95% will adhere to the Al ₂ O ₃ film, and the hardened Al ₂ O ₃ film will be mechanically peeled off. The manufacturing structure is outlined in Figure 20. Due to the different surface energies, the adhesion between Cr and Ag is weak, and therefore can be easily overcome by applying stress. The applied stress consists of a pure tensile stress mode and a shear stress mode. These two modes will ensure complete separation between Ag and Cr. Under the applied stress, the hardened Al ₂ O ₃ film itself separates from the rigid substrate together with the sacrificial Ag layer and the flexible transparent polyester tape, as shown in FIG. 21. Finally, the sacrificial Ag layer will be etched away by immersing the assembly with acid. The assembly is shown in Figure 21. The acid is diluted HNO ₃ (1:1). Since the tape and Al ₂ O ₃ film are acid resistant, the etchant solution will only etch away the sacrificial Ag layer relatively quickly. After the Ag film is completely etched away, Al ₂ O ₃ will be completely transferred to the PET substrate shown in FIG. 22.

result

Figure 23 shows a sample fabricated to transfer Al ₂ O ₃ thin films. On the fused silica substrate, Cr is first sprayed on the substrate with a sputtering rate of about 5nm/min, and its general thickness is 50nm. Then, 50nmAg will be deposited on top of it by electron beam evaporation. Finally, about 200nm thick Al ₂ O ₃ will be deposited on the assembly by electron beam evaporation.

Figure 24 shows the separation of the Al ₂ O ₃ film from the fused silica substrate and Cr after applying mechanical peeling with a transparent tape. Al ₂ O ₃ together with the Ag film and tape are completely and smoothly separated from the rigid substrate without any cracks or bubbles. After etching off the sacrificial Ag layer in acid, Al ₂ O _{3 was} successfully transferred to the flexible PET substrate.

In another embodiment of the present invention, through their experiments, experiments and research, the inventors discovered and completed the deposition of a higher hardness (sapphire) film layer onto a lower hardness substrate, such as soda lime glass (SLG) , Quartz and toughened glass. This composition will be better than sapphire alone. In the natural state, materials with higher hardness will have poor toughness. Therefore, the sapphire substrate is difficult to scratch, but it is easy to break. Coating a harder film on a weaker substrate is the best combination. Substrates with relatively weak hardness have low fracture probability, good mechanical properties and low cost. The anti-scratch function can be achieved by using a thin film coating with higher hardness.

In the present invention, a method for depositing a high-hardness aluminum oxide (alumina) film on a quartz substrate is provided. The film thickness is in the range of 100nm-1000nm. By post-deposition treatment, such as thermal annealing at 25°C-375°C and 25°C as room temperature, the embodiment of the present invention has reached a hardness exceeding 14 GPa, which is higher than the 8-8.5 GPa of uncoated soda lime glass Generally the hardness is still hard. This technology is called "sapphire film coated substrate". Therefore, in terms of hardness, the sapphire film-coated substrate is comparable to a pure sapphire screen, and since the density of quartz is only 2.65g/cm ³ and the density of sapphire is 3.98g/cm ³ , its weight is almost the same as that of glass/quartz base Compared with the pure sapphire substrate, it is only about 66.6% of the weight. Since the substrate can be cut to the required size, and then the sapphire film is deposited, the manufacturing cost and time will be significantly reduced compared to the pure sapphire substrate.

The aluminum oxide film is spray-coated on the soda lime glass and annealed at 25°C for 0.5 hours, and it is found to be harder than the uncoated soda lime glass. The film hardness is increased to more than 14GPa. Therefore, the hardness of the annealed alumina film on the soda lime glass substrate is greater than that of the uncoated soda lime glass.

Moreover, in the present invention, the annealing procedure of the aluminum oxide film on other substrates is performed at room temperature.

Deposition procedure

Depositing substrate, such as soda lime glass, quartz, glass.

The substrate temperature during deposition: room temperature to 1000°C.

Film thickness: 100nm-1000nm.

Thermal annealing time: 30 minutes to 2 hours.

The deposition of aluminum oxide film is sputtering or electron beam.

The thickness of the film deposited on the substrate is about 100 to 1000 nm, and the deposition rate is about 1 Å/s. The substrate is not externally cooled or heated during deposition. The film thickness is measured by ellipsometry.

After the aluminum oxide film is deposited on the substrate, they are annealed at 25°C. The time range is from 30 minutes to 2 hours, during which a specific thermal annealing temperature will be maintained.

The deposition substrate includes soda lime glass.

The results of nanoindentation of alumina film on soda lime glass (SLG) under different annealing conditions are shown in Figure 25.

Further embodiment of the invention

In a further embodiment of the present invention, the doped aluminum oxide (sapphire) thin film layer can be deposited on the sapphire thin film coated substrate and used as a strengthening layer. Figure 26 shows the structure of this sample. Compared to aluminum, dopant materials need to be quite different in atomic size, such as chromium or chromium oxide, magnesium or magnesium oxide. Two kinds of atoms of different sizes will form the connection mechanism in the film, which can increase the surface hardness of the film. This connection mechanism is similar to chemically strengthened glass, which uses potassium instead of sodium in the glass. The transmittance and hardness of the sample can be controlled by the thickness, doping ratio and doping material of the strengthening layer.

The unique doping of this kind of aluminum oxide (sapphire) film can also be used as a unique identifier for a specific aluminum oxide (sapphire) film coating coated on a specific substrate. Therefore, another embodiment of the present invention provides a manufacturing method, which can track the doped sapphire coating they make by identifying the proportion and type of dopants in the doped sapphire thin film coating.

In one of the experiments described in the present invention, when the ratio of the strengthening layer is 1:3 (aluminum oxide: chromium oxide), its thickness is about 30nm, and it is placed on a 200nm sapphire film coated substrate, and thermally annealed at 300°C , On the nanoindentation measurement (Figure 27), the present invention has reached a hardness of 17GPa, which is equivalent to 7.2-7.5 Mohs on the Mohs scale.

In another experiment, it was described that when the ratio of the strengthening layer is 1:1 (aluminum oxide: magnesium oxide), its thickness is about 30nm, and it is located on a 200nm sapphire film coated substrate, and it is at room temperature without annealing , On the nanoindentation measurement (Figure 28), the present invention has reached a hardness of 17GPa, which is equivalent to Mohs scale 7.2-7.5 Mohs. Figure 28 shows the data of strengthening layers deposited on different substrates at room temperature with a ratio of 1:1 (aluminum oxide: magnesium oxide), namely soda lime glass (SLG) and chemically strengthened aluminosilicate glass (ASS). These data are shown in Table 9.

Figure 29 shows the transmittance of the samples. These samples have different strengthening layer ratios. When the strengthening layer ratio is 1:2 (alumina: chromium oxide), the transmittance in the visible light range is about 80%.

Figure 30 shows the transmittance of samples deposited on two different substrates at room temperature. These samples have different strengthening layer ratios of 1:1 (alumina: magnesia). The substrate is Soda lime glass (SLG) and chemically strengthened aluminosilicate glass (ASS). When the ratio of the strengthening layer is 1:1 (alumina: Magnesium oxide), the transmission rate in the visible range (400nm to 700nm) is greater than 90%. These data are shown in Table 10.

The as-deposited sapphire film deposited by electron beam or sputtering has a hardness value of about 12-13 GPa, which is about 5.5-6.5. After the thermal annealing process, the film hardness will increase significantly. However, the softening point of glass is about 500°C, which means that the annealing temperature will not be high enough to convert sapphire into crystals. On the other hand, due to the strengthening of the layer, strengthened glass (such as Corning's Gorilla Glass) even has a lower annealing temperature of 400 ℃. After adding a strengthening layer doped with aluminum, the hardness of the film will increase to 7.2-7.5 Mohs at a specific doping ratio of the strengthening layer and an annealing temperature of 300°C. For strengthened glass substrates treated at lower annealing temperatures, this method can bring significant improvements to the surface hardness and decompression problems.

The procedure of depositing the doped alumina strengthening layer on the sapphire film coated substrate by sputtering deposition is described as follows:

1. The deposition of sapphire film follows the same process as in the U.S. non-provisional patent application "Sapphire Film Coated Substrate" filed on March 9, 2015 with application number 14/642,742. To proceed with the preamble and experimental details, this patent claims the priority of the US provisional patent application filed on September 12, 2014 with application number 62/049,364.

2. The base vacuum of the chamber is higher than 5x10 ^-6 mbar, and when deposition occurs, the deposition vacuum is maintained above 5x10 ^-3 mbar.

3. The substrate is attached to the sample holder at a distance from the splash source, for example, the distance is 150 mm. When deposition occurs, the sample holder is rotated at 10 RPM.

4. Co-sputtering technology is used to deposit a doped aluminum oxide layer on the sample. Two spray guns containing two different targets will operate synchronously during coating, and the doping ratio will be controlled by the spray force. It is also possible to perform electron beam deposition in a similar configuration.

5. The thickness of the doped aluminum oxide layer is 10 nm to 100 nm, and depends on the target material used, such as oxide and metal targets, and the deposition rate is about 1-20 nm/min. The substrate is at room temperature during deposition, and the active temperature is not necessary. The film thickness can be measured by ellipsometry or other suitable methods with similar or better accuracy.

6. After the doped aluminum oxide layer is deposited on the sapphire film coated substrate, they are annealed in a furnace at 50°C to 1300°C. The temperature rise gradient should be gradual, such as 5°C/min, and the drop gradient should also be gradual, such as 1-5°C/min. Within the specific thermal annealing temperature range, the annealing time is between 30 minutes and 10 hours. Multiple annealing steps at different temperatures within the above range can also be used to enhance the hardness and reduce the microcracks of the film.

Other possible dopants include beryllium, beryllium oxide, lithium, lithium oxide, sodium, sodium oxide, potassium, potassium oxide, calcium, calcium oxide, molybdenum, molybdenum oxide, tungsten, and tungsten oxide. In fact, one embodiment of the present invention has spinel (MgAl ₂ O ₄ ), which is manufactured in a doped alumina (sapphire) thin film coating, which is on a softer substrate, and The ratio of alumina: magnesia is 1:1. From the data in Figure 31, it can be observed that when a doped aluminum oxide (sapphire) film with MgO mixed oxide (aluminum oxide to magnesium oxide ratio of 1:1) is deposited on fused silica (FS ) On the substrate and annealed at different temperatures, that is, at room temperature (RT), at 200°C (S 200A), at 400°C (S 400A), at 600°C (S 600A), At 800°C (S 800A) and at 1000°C (M 1000A), different grades/concentrations of spinel can be detected using XRD, and it is obvious that the most prominent peak of spinel is at 1000°C Measured under (M 1000A). In any case, even at room temperature (RT), the XRD signal of the spinel can still be detected, and when it is not annealed, that is, at room temperature (RT), the doped sapphire film with MgO is just right In the hardest state. Moreover, at 1000°C (M 1000A), the XRD peak of alumina is detected, and except for 1000°C (M 1000A), under all the tested annealing temperature conditions, the XRD peak representing MgO will also be detected. Detected. The physical deposition process used can be electron beam deposition or sputtering, wherein the deposition is not externally cooled or heated, and the entire process will be completed at room temperature. Moreover, according to the information presented in Table 11, it can be seen that the aluminum oxide (sapphire) thin film layer is used to provide adhesion to bond the MgO mixed oxide to the substrate during deposition at room temperature.

Further embodiment of the invention

Sapphire film has mechanical properties of high hardness, which means that it is very hard. Therefore, when it is deposited on a soft or flexible substrate, and the film is too thick or cracked due to the stress between the substrate and the film, the sapphire The difference in mechanical properties with the substrate will cause the film to peel off. For example, when the film thickness exceeds 200nm, the sapphire film will begin to peel off the PMMA or PET substrate.

In addition, the difference in refractive index between the two materials indicates that the light passing through will be trapped between the two materials. Therefore, a further embodiment of the present invention provides a buffer layer, which can be used as a mechanical and optical intermediate layer. In terms of mechanical properties, the buffer layer is hard and sandwiched between the soft substrate and the sapphire film, which can relieve the high stress caused by the large difference in hardness between the two materials. Within the optimal thickness range, thicker sapphire film can be grown. Because it is necessary to have enough thickness to prevent the film from being broken or punctured to resist scratches, a thicker sapphire film is required. In addition, the buffer layer can reduce the stress between the interfaces, so that the film has better adhesion.

Further invention

The embodiment of the present invention proposes:

1. A buffer layer with a thickness of 10-100nm is deposited on a softer substrate, such as PMMA and PET.

2. The deposition method can be thermal deposition, sputtering or electron beam, and does not require heating of the substrate, that is, it is deposited without external cooling or heating.

3. The mechanical hardness of the buffer layer material should be higher than the base material and lower than the general sapphire film. The general hardness scale is in the range of 1-5.5 Mohs.

4. The refractive index of the buffer layer material should be higher than the substrate but lower than the general sapphire film. The general refractive index is in the range of 1.45-1.65.

5. This buffer layer can also improve the adhesion of the sapphire film, because it can reduce the stress caused by the large difference in hardness.

6. One example of this material is silicon dioxide (SiO ₂ ).

Using SiO ₂ as the buffer layer, the thickness of the sapphire layer on PMMA can be increased to 300 nm before film peeling is observed. For a sapphire film without SiO ₂ , film peeling can be observed at a thickness of 150 nm or more (the "peeling" thickness can be referred to as the critical thickness). Therefore, the buffer layer improves the mechanical stability of the sapphire film, so that the critical thickness is increased by more than 100%.

The introduction of SiO ₂ as a buffer layer improves the overall light transmission rate of the coated substrate in the optical range by less than 2%. The enhancement of the transmittance brings about the matching of the refractive index of the buffer layer, so that the light energy can pass through the substrate to the sapphire film with a lower loss. This enhancement can be attributed to the decrease in the refractive index difference between the two material layers (such as the substrate and the buffer layer, the buffer layer and the sapphire film), and the decrease in the refractive index will increase the Brewster angle, It defines the amount of light that penetrates from one medium, through the interface between the mediums, to another medium. The larger the Brewster angle, the more light can penetrate this interface. Therefore, the introduction of a buffer layer between the substrate and the sapphire film can increase the amount of light penetration. This is shown in Figure 32.

As shown in Figure 33, when measured by nanoindentation, the hardness can reach at least 5 GPa or higher when the thickness is 200 nm or more (buffer layer and sapphire film). This is a significant improvement in the hardness of uncoated substrates. For example, the hardness of PMMA is 0.3GPa, which can reach 5.5GPa after improvement, which means that the hardness has increased by more than ten times, and this also proves that by introducing a buffer layer between the soft substrate and the sapphire film, the hardness and light penetration can be enhanced. Firing rate.

Further embodiment of the invention

The further embodiments of the present invention described herein are not intended to limit the scope of any specific embodiments, and are merely presented as examples.

Without wanting to be limited by theory, the inventors have discovered the design of the composition of the AR layer through their experiments, experiments, and research. The purpose is to match the underlying substrate such as glass, chemically strengthened glass and plastic. Refractive index to maximize the transmitted light. For devices with a sapphire film with anti-scratch protection, since sapphire has a different refractive index from the underlying substrate, the existing AR layer will not be able to perform its due function. Not only is the amount of light penetrating in the past reduced, its transmission range will also be changed, which will damage the image and/or the color of the display. Therefore, an integrated AR with a sapphire film with the top AR layer eliminates this problem. The top AR layer is Al ₂ O ₃ and can also be used as an anti-scratch layer. This involves replacing one of the materials in the AR layer with Al ₂ O ₃ , so that the top AR layer is Al ₂ O ₃ , which can also serve as a scratch-resistant layer.

Further embodiments of the present invention propose the following characteristics:

1. Use Al ₂ O _{3 to} replace one of the AR coatings to achieve anti-reflection function;

2. Usually at least two AR materials are Al ₂ O ₃ and TiO ₂ , and the refractive index difference between these two materials should be as large as possible.

3. The top AR layer should be Al ₂ O ₃ , which can also serve as a scratch-resistant layer.

4. The number of layers is from 4 to 20.

5. The deposition procedure can be RF, DC sputtering or a combination thereof, and/or electron beam deposition.

6. The annealing temperature ranges from 50 to 800°C, and annealing is used to further increase the scratch resistance.

7. The annealing time is 0.5 to 2 hours.

8. Without annealing, AR or scratch resistance will not decrease.

9. The doped sapphire can be an additional layer on the top sapphire layer to further increase the hardness.

10. Before integrating the deposition of AR and scratch-resistant layer, a buffer layer can be added to the flexible/soft substrate to improve adhesion.

11. It can be applied to mobile phones, watches, camera lenses, binoculars, glasses, tablets and optical sensors.

Use Al ₂ O _{3 to} replace one of the AR film layers to achieve the anti-reflection function.

Figure 34 shows the AR structure in which Al ₂ O ₃ is used to replace the top AR film to achieve not only the anti-reflection function, but also the anti-scratch function. By matching the refractive index of other deposited AR layers to the substrate and the top Al ₂ O ₃ layer alternately high and low, this structure can generally be applied to all transparent substrates.

AR structure design

2 ^nd outermost layer of n>1.75

The composition of the AR layer is used to match the refractive index of the top sapphire layer and the underlying substrate. In one embodiment, as shown in FIG. 35, in the visible light range, the refractive index of the specific AR layer below the outermost sapphire layer must be higher than the refractive index of Al ₂ O ₃ , and the range is 1.75 to 1.78. TiO ₂ is a typical AR material with a refractive index higher than that of Al ₂ O ₃ . Fig. 36 and Fig. 37 show other embodiments, which are respectively an AR structure with TiO ₂ on a glass substrate and its transmission simulation.

In the AR structure, a possible material with n>1.75 is used as the second outer layer

All materials with a refractive index higher than 1.75 in the visible light range can be considered as possible candidates for the second outer layer in the AR structure. These materials include YAG, AlAs, ZnSiAs2, AgBr, TlBr, C, B ₄ C, SiC , AgCl, TlCl, BGO, PGO , CsI, KI, LiI, NaI, RbI, CaMoO 4, PbMoO 4, SrMoO 4, AlN, GaN, Si 3 N 4, LiNbO 3, HfO 2, Nb 2 O 5, Sc 2 O ₃ , Y ₂ O ₃ , ZnO, ZrO ₂ , GaP, KTaO ₃ and BaTiO ₃ . The other embodiments shown in FIG. 38 and FIG. 39 are respectively an AR structure with ZrO ₂ on a glass substrate and its transmission simulation. The embodiments shown in FIG. 40 and FIG. 41 are respectively an AR structure with HfO ₂ on a glass substrate and its transmission simulation. The other embodiments shown in FIG. 42 and FIG. 43 are respectively an AR structure with GaN on a glass substrate and its transmission simulation.

AR structure on different substrates

In addition to being deposited on glass and chemically strengthened glass substrates, AR structures can also be applied to substrates of other materials, such as sapphire, quartz, fused silica and plastics. The embodiments shown in Figure 44, Figure 45, Figure 46 and Figure 47 are respectively AR structure on sapphire substrate, specific AR transmission simulation on sapphire, AR structure on PMMA substrate, and specific AR structure on PMMA. AR transmission simulation.

For the first AR layer of the three-layer AR structure

For a total of three layers of AR structure, the first AR layer deposited on the substrate of materials other than sapphire is Al ₂ O ₃ . For the sapphire substrate, the refractive index of the material of the first AR layer is lower than Al ₂ O ₃ , namely 1.75. A typical material with a low refractive index is MgF ₂ . The embodiments shown in FIG. 48 and FIG. 49 are respectively a three-layer AR structure on a substrate made of materials other than sapphire and a sapphire substrate. Figure 50 and Figure 51 respectively show the transmission simulation of the three-layer AR structure with the second outer AR layer of TiO ₂ on the glass substrate and the second outer AR layer on the sapphire substrate with TiO ₂ and the first AR. Transmission simulation of a three-layer AR structure with MgF ₂ layer.

Minimum thickness of AR layer

The thickness of each AR layer should be at least 10 nm, and a film with a thickness of less than 10 nm may not be a physically complete film. In these AR layers and the substrate, the matching of the refractive index will be affected by the change of the refractive index of these layers. In addition, when the film thickness is less than 10 nm, the refractive index of the layer cannot be accurately measured. The refractive index of the ultra-thin film is very different from that of the bulk material, and this difference will shrink when the film thickness is equal to or more than 10 nm. Fig. 52 shows the refractive index of a two-layer structure with different thicknesses alternately formed with Al ₂ O ₃ and ZnO. It can be seen that when the thickness of the two-layer film is higher than 10 nm, the refractive index changes less.

Maximum thickness of AR layer

Fig. 54 shows the structure transmission simulation of other embodiments, which is a three-layer AR on a glass substrate with a second outer layer of TiO ₂ as shown in Fig. 53 and different thicknesses of Al ₂ O ₃ The thickness of the first AR layer is increased from 400 nm to 1000 nm. By comparing the average transmittance of the glass substrate and the AR structure with the first Al ₂ O ₃ AR layer of 1000 nm in the visible light range, it can be known that after the effect of AR is eliminated, those with AR have lower transmittance. The maximum thickness of the AR layer cannot exceed 800 nm.

In the AR composition, a possible material with n<1.75 as a low refractive index layer is used

Except for MgF ₂ , all materials with a refractive index lower than 1.75 in the visible light range can be considered as possible candidates for the low refractive index layer in the AR structure. These materials include KCl, NaCl, RbCl, CaF ₂ , KF, LaF _3. LiF, LiCaAlF ₆ , NaF, RbF, SrF ₂ , ThF ₄ , YLiF ₄ , GeO ₂ , SiO ₂ , KH ₂ PO ₄ and CS ₂ . Figure 55 and Figure 56 respectively show a three-layer AR structure with SiO ₂ as the first AR layer on a sapphire substrate and its transmission simulation. Fig. 57 and Fig. 58 show further embodiments, respectively, a three-layer AR structure with LiF as the first AR layer on a sapphire substrate and its transmission simulation. The embodiments shown in FIGS. 59 and 60 are respectively a three-layer AR structure with KCl as the first AR layer on a sapphire substrate and its transmission simulation.

For AR layers with more than three layers, examples of AR compositions

The embodiments shown in Figure 61 and Figure 62 are respectively a five-layer AR structure on a glass substrate and a six-layer AR structure on a sapphire substrate. For these two structures, when TiO ₂ is used as the second In the case of the outer layer, SiO ₂ is regarded as a low refractive index AR layer. Figure 63 and Figure 64 show the transmission simulation spectra, respectively.

Generally speaking, the AR layer includes alternating Al ₂ O ₃ films and low refractive index layers deposited on the substrate. For substrates of materials other than sapphire, the Al ₂ O ₃ AR layer is deposited first, followed by the low refractive index layer, while for sapphire substrates, the opposite is the case, that is, the Al ₂ O ₃ AR layer It is deposited after the low refractive index layer is deposited first. These sequences can be extended to a larger number of layers. The high refractive index AR layer as the second outer layer is coated on top of a pair of Al ₂ O ₃ and low refractive index layers, and finally the top Al ₂ O ₃ AR layer is made.

Figures 65 and 66 show general embodiments of the present invention, which are AR composition substrates and sapphire substrates of materials other than sapphire, respectively.

Experimental results on simulated transmission

Fig. 67 shows an example of AR structure of [glass/Al ₂ O ₃ (160nm)/LiF (75nm)/Al ₂ O ₃ (80nm)/TiO ₂ (96nm)/Al ₂ O ₃ (75nm)], There are simulations of only glass substrates, specific compositions, and transmission of AR layer coating samples made by electron beam evaporation and sputtering. As shown in Figure 67, the agreement between the experimental transmission and the simulation is very high. Comparing the experimental results with the simulated data, the difference in the average transmittance in the visible light range is less than 1%. With the AR structure, more light from 91.7% to 94% will penetrate the substrate in the visible light range. This also proves that AR structures can be manufactured by different physical vapor deposition (PVD) methods, such as electron beam evaporation and sputtering.

The embodiments of the present invention can also be applied to soft and flexible substrates, such as polymers, plastics, paper, and fabrics.

Modifications and changes that are obvious to the skilled person can be regarded as within the scope of the present invention.

Other further embodiments of the present invention will be described later:

AR composition with diamond-like carbon (DLC) layer

The AR structure can be combined with a diamond-like carbon (DLC) layer to reduce light reflection. FIG. 68 shows the simulated transmission spectrum of an AR structure having a diamond-like carbon layer in the composition on a sapphire substrate.

Another embodiment of the invention

The aforementioned claimed invention provides a method that can deposit one or more layers of sapphire/alumina film with higher hardness on a substrate with a lower hardness and a maximum allowable annealing temperature of less than 850°C, such as Gorilla Glass and Steel Chemical glass, soda lime glass, mineral glass, metal and various types of plastics such as PMMA, polyimide (PI), etc. Therefore, a harder scratch-resistant film can be coated on the glass. This is the fastest and lower cost method to improve their surface hardness.

Recently, it has been shown that for ultra-thin oxide films of 10 nm or smaller, especially aluminum oxide and silicon oxide, the superplastic properties are very prominent, which makes the ultra thin film extremely easy to stretch. This means that when the film is stretched, it will not break, and even if it does, it will recover on its own. So when it is bent/stretched in a foldable/wearable device, the film will maintain its properties without deterioration.

Therefore, when a film, such as a single layer or multiple layers, is sandwiched between other layers, it/they will not break and maintain a complete multilayer structure, thereby maintaining its functionality, such as scratch resistance.

In the claimed invention, a method of depositing a multilayer, flexible, scratch-resistant coating is provided. The coating includes a first ultra-thin metal oxide layer, namely sapphire/Si oxide, which is deposited on the substrate and has a thickness of 1-50 nm. Next, a second thicker oxide film is deposited. If the first ultra-thin layer is sapphire, the subsequent second layer can be SiO ₂ or other oxides. If the first ultra-thin layer is SiO ₂ , the subsequent second layer can be sapphire or other oxides. The thickness of the thicker oxide film is in the range of 10-2000 nm, and the first ultra-thin layer may be optional.

The third layer and the fourth layer may be the repetition of the first layer and the second layer, and this deposition may be repeated several times. Finally, the top layer or the top layer should be sapphire or a mixture thereof, including metals such as Mg, Si, Ti, etc., and the thickness of the top layer should be within 20-200 nm.

The thickness of the ultra-thin metal oxide layer should be between 1-50 nm, which is deposited by deposition methods such as electron beam evaporation or sputtering. The thickness of the thicker oxide film is in the range of 10-2000 nm.

When the coating is bent and stretched, the ultra-thin aluminum oxide/silicon layer with a thickness of 1-50nm can maintain the integrity of the multilayer coating. Its liquid-like state exhibits superplastic properties, which allows severe bending and Stretch without permanent fracture. The top layer functions as an anti-scratch layer. Fig. 74 schematically shows the structure of the claimed invention.

Manufacturing process

1. Referring to the schematic diagram of FIG. 74, the deposition of the metal oxide layer 101 such as Al, Ti, Cr, Ni, Si, Ag, or Zr oxide is using a deposition method such as electron beam evaporation or sputtering. The thickness of the metal oxide layer 101 directly deposited on the substrate 100 is about 1-50 nm.

2. Next is a thicker oxide film 102; if the ultra-thin layer 101 is SiO ₂ , the connecting layer 102 can be sapphire or other oxides. If the ultra-thin layer 101 is sapphire, the connecting layer 102 may be SiO ₂ or other oxides. The thickness of the thicker oxide film is in the range of 10-2000 nm, and the ultra-thin layer 101 is optional.

3. The third layer 103 and the fourth layer 104 are optional, and may be a sequential repetition of the first layer and the second layer. And, this deposition can be repeated several times (the number of repetitions depends on each specific mechanical requirement).

4. The final top layer 105 can be sapphire or a mixture thereof, such as sapphire mixed with Mg, Si, Ti, etc., or SiO ₂ , or other oxides, and the thickness of the top layer 105 is in the range of 20-200 nm.

5. This substrate can be sapphire, quartz, fused silica, gorilla glass, tempered glass, soda lime glass, mineral glass, metal, various types of plastics such as PMMA, polycarbonate (PC), polyterephthalene Ethylene formate (PET) and/or polyimide (PI) or any combination thereof.

6. The multi-layer coating or film formed on the substrate is used for scratch resistance and acts as a barrier to prevent the diffusion of water and oxygen. Multilayer films are highly flexible and suitable for foldable/wearable electronic products.

Nanoindentation hardness of deposited films on different plastic substrates

Use the hardness of coated ABS and uncoated PMMA as a comparison

Figure 69A shows the hardness of coated ABS with (open square) and without (open circle) SiO ₂ buffer. Compare the hardness of the coated ABS shown in FIG. 69A with the hardness of the uncoated ABS and PMMA of FIG. 69B.

Figure 70 shows the hardness of coated and uncoated PI (top and bottom), while the hardness of quartz, fused silica and SLG are for reference.

Figure 71 is a summary of the hardness measured at the coated PI; a single layer of Al ₂ O ₃ film or multiple layers including Al ₂ O ₃ . The hardness of coated PI is compared with quartz, fused silica, coated and bare SLG, and bare PI. The hardness of the two coated PIs is comparable to that of the bare SLG. Table 12 summarizes the hardness, calibration hardness and Mohs hardness of the different samples.

Table 12 shows that an increase in the thickness of the Al ₂ O ₃ layer (from 130 to 160 nm) will lead to an increase in indentation hardness

Film on PC and PCPMMA

Figure 72 shows the corresponding hardness of coated PC and PCPMMA. FIG. 72 also shows the coated PC and has the hardness of Al ₂ O ₃ , and shows the hardness of quartz and fused silica as a reference. Coated PC is harder than fused silica.

Table 13 shows that compared to the surface hardness of Al ₂ O ₃ , the surface hardness of doped Al ₂ O ₃ will be improved accordingly.

As the interface layer, with different SiO ₂ The thickness of the coated PMMA hardness.

FIG. 73 shows PMMA coated with a multilayer structure of SiO ₂ as a buffer layer and Al ₂ O ₃ with a thickness of 200-500 nm, and the hardness of the coated PMMA is 6 to 8 times higher than that of bare PMMA.

PI with typical multilayer structure

Table 14: Typical multilayer structure deposited on PI

Structure S1PI-D vs. S1PI-S (i.e. different cushioning materials)

Table 14 shows that the structure of the samples with different buffer materials resulted in similar performance.

Table 15 shows the hardness of samples with different cushioning materials and substrates.

According to the first aspect of the present invention, it proposes a method for forming a substrate with a flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate. The coating includes: combining two different metals The oxide layer is deposited on the substrate as layer 101 and layer 102, wherein the thickness of the metal oxide layer 101 is in the range of 1 nm to 50 nm, and the thickness of the metal oxide layer 102 is in the range of 10 nm to 2000 nm; and an Al ₂ O ₃ or a final top layer 105 of a mixture thereof is deposited on the two different metal oxide layers, the mixture containing a metal selected from Mg, Si or AF, or selected from Si oxide, Ti oxide, Cr oxide, Ni The metal oxide of oxide, Ag oxide or Zr oxide, and wherein the thickness of the top layer ranges from 20 nm to 200 nm.

In the first embodiment of the first aspect of the present invention, the method is provided, in which a metal oxide layer 103 is deposited on the two different metal oxide layers 101, 102 to form alternating three metal oxide layers. The oxide layers 101, 102, 103, wherein the metal oxide layer 103 is the same as the metal oxide layer 101 and different from the metal oxide layer 102, and wherein the final top layer 105 is deposited on top of the layer 103 to A multilayer structure of metal oxide layers 101, 102, 103, and 105 is formed.

In the second embodiment of the first aspect of the present invention, the method is provided, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form Into an alternating four metal oxide layers 101, 102, 103, 104, wherein the metal oxide layer 104 is the same as the metal oxide layer 102 and different from the metal oxide layer 101, and the final top layer 105 is deposited on On the top of the layer 104, a multilayer structure of metal oxide layers 101, 102, 103, 104 and 105 is formed.

In a third embodiment of the first aspect of the present invention, the method is provided, wherein, before depositing the final top layer 105, at least one of the alternating metal oxide layers is further deposited to form a metal oxide Multi-layer structure.

In a fourth embodiment of the first aspect of the present invention, the method is provided, wherein any one or all of the deposition is performed by a physical vapor deposition method selected from an electron beam evaporation deposition process or a sputter deposition process .

In the fifth embodiment of the first aspect of the present invention, the method is provided, wherein the substrate includes sapphire, quartz, fused silica, gorilla glass, tempered glass, soda lime glass, mineral glass, metal And/or plastic polymer, and any combination thereof, and wherein the plastic polymer includes PMMA, polycarbonate, polyethylene terephthalate, and polyimide.

In the sixth embodiment of the first aspect of the present invention, the method is provided, wherein the metal oxide layer 101 or the metal oxide layer 102 is selected from Al oxide, Ti oxide, Cr oxide, Ni Oxide, Si oxide, Ag oxide or Cr oxide, but the two metal oxide layers are different.

According to the second aspect of the present invention, it provides a substrate with a multilayer, flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate, the coating includes: two different metals An oxide layer, which is layer 101 and layer 102, which are deposited on the substrate, wherein the thickness of the metal oxide layer 101 is in the range of 1 nm to 50 nm, and the thickness of the metal oxide layer 102 is in the range of 10 nm to 2000 nm; and , A final top layer 105 of Al ₂ O ₃ or a mixture thereof, which is located on two different metal oxide layers, the mixture includes a metal selected from Mg, Si or AF, or selected from Si oxide, Ti oxide , Cr oxide, Ni oxide, Ag oxide, or Zr oxide, and the thickness of the top layer ranges from 20 nm to 200 nm.

In the first embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein a metal oxide layer 103 is deposited on the two metal oxide layers 101, 102 to form Three alternate metal oxide layers 101, 102, 103, wherein the metal oxide layer 103 is the same as the metal oxide layer 101 or different from the metal oxide layer 102, and the final top layer 105 is deposited on the layer 103 To form a multilayer, flexible and scratch-resistant coating of these layers 101, 102, 103 and 105.

In a second embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form an alternating four metal oxide layers 101, 102, 103, 104, wherein the metal oxide layer 104 is the same as the metal oxide layer 102 or the metal oxide layer 101 is different, and the final top layer 105 is deposited on top of the layer 104 to form a multilayer, flexible and scratch-resistant coating of the layers 101, 102, 103, 104, and 105.

The coating is provided in the third embodiment of the second aspect of the present invention, wherein, before the final top layer 105 is deposited, at least one of the alternating metal oxide layers is further deposited to form the multilayer, flexible With anti-scratch coating.

In a fourth embodiment of the second aspect of the present invention, the substrate with the coating is provided, wherein the deposition is performed by a physical vapor deposition method including an electron beam evaporation deposition process or a sputter deposition process .

In the fifth embodiment of the second aspect of the present invention, the coating is provided, wherein the substrate includes sapphire, quartz, fused silica, gorilla glass, tempered glass, soda lime glass, mineral glass, One or more of metals, and/or plastic polymers, or any combination thereof, and wherein the plastic polymers include PMMA, polycarbonate, polyethylene terephthalate, and polyimide.

In the sixth embodiment of the second aspect of the present invention, the coating is provided, wherein the metal oxide layer 101 or the metal oxide layer 102 is selected from Al oxide, Ti oxide, Cr oxide, Ni Oxide, Si oxide, Ag oxide or Cr oxide, and the two metal oxides are different.

If necessary, the different functions discussed herein can be executed in a different order and/or simultaneously with each other. In addition, if necessary, one or more of the above functions can be arbitrarily selected or can be combined.

In the entire specification, unless other explanations are required in the context, the word "comprise" or its variations, such as "comprises" or "comprising", can be understood as including all Mention of a whole or group of wholes does not exclude any other whole or group of wholes. It should also be noted that in this disclosure, and especially in the scope and/or paragraphs of the patent application, some terms such as "comprises", "comprised", "comprising" and similar terms , May have the meaning attributed to the US patent law. For example, these terms can mean "includes", "included", "including" and similar terms; and for example, "consisting essentially of" and " Terms such as "consists essentially of" have the meaning described in the US patent law. For example, they allow elements that are not explicitly cited, but exclude elements that are available in the prior art or that may affect the basic or novel characteristics of the invention.

In addition, in the entire specification and the scope of the patent application, unless other explanations are required in the context, the word "include" or the modified term, such as "includes" Or "including" can be understood as including the mentioned whole or group of wholes, but does not exclude any other whole or whole group.

For other definitions of terms selected here, they can be found in the detailed description of the present invention and applied anywhere. Unless there are other definitions, all other technical terms used herein have the same meaning as generally understood by those skilled in the art.

The above-mentioned invention has been described with respect to various embodiments and examples, but it should be understood that other embodiments are still within the scope of the following claims and their equivalent scope. In addition, the above specific embodiments should be construed as only illustrative in nature, without limiting the rest of the disclosure in any way. It is believed that those skilled in the art can use the present invention to the fullest extent based on the description herein without further elaborate design. All publications listed in this article are incorporated by reference in their entirety.

In this document or anywhere else, any reference or clarification should not be construed as an admission that such reference documents can be used as prior art in this application

Industrial applicability:

The present invention relates to a composition of a multilayer metal oxide protective coating deposited on a substrate, wherein the topmost layer contains Al ₂ O ₃ or a mixture thereof, so that the topmost layer also serves as a scratch-resistant layer. The multilayer metal oxide protective coating also maintains the flexibility of the underlying substrate.

100: substrate

101, 102, 103, 104, 105: layer (film)

Claims (12)

A method of forming a substrate with a multilayer, flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate, the method includes: depositing two different metal oxide layers on the substrate The thickness of the metal oxide layer 101 is in the range of 1nm to 50nm, and the thickness of the metal oxide layer 102 is in the range of 10nm to 2000nm, wherein the metal oxide layer 101 or the metal The oxide layer 102 is selected from Al oxide, Cr oxide, Ni oxide, Ag oxide, Zr oxide or a combination thereof, but the two metal oxide layers are not the same; and an Al ₂ O ₃ or a combination thereof The final top layer 105 of the mixture is deposited on the two different metal oxide layers. The mixture contains selected from Mg, Si, AF, Si oxide, Ti oxide, Cr oxide, Ni oxide, Ag oxide or Zr. A substance of oxide, and the thickness of the top layer ranges from 20 nm to 200 nm. The method according to claim 1, wherein a metal oxide layer 103 is deposited on the two different metal oxide layers 101, 102 to form three alternate metal oxide layers 101, 102, 103, The metal oxide layer 103 is the same as the metal oxide layer 101, and the final top layer 105 is deposited on the top of the layer 103 to form a multilayer structure of metal oxide layers 101, 102, 103, and 105. The method according to claim 2, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form an alternating four metal oxide layers 101, 102, 103, 104, wherein the metal oxide layer 104 is the same as the metal oxide layer 102, and The final top layer 105 is deposited on top of the layer 104 to form a multilayer structure of metal oxide layers 101, 102, 103, 104, and 105. The method according to claim 3, wherein, before depositing the final top layer 105, at least one of the alternating four metal oxide layers is further deposited to form a metal oxide multilayer structure. The method according to claim 1, wherein any one or all of the deposition is performed by a physical vapor deposition method selected from an electron beam evaporation deposition process or a sputter deposition process. The method according to claim 1, wherein the substrate comprises one or more of sapphire, quartz, fused silica, strengthened glass, tempered glass, metal, and/or plastic polymer, and any combination thereof, and The plastic polymer includes polymethyl methacrylate, polycarbonate, polyethylene terephthalate, or polyimide. A substrate with a multilayer, flexible and scratch-resistant coating, and the coating is a protective barrier in the environment of the substrate, the coating includes: two different metal oxide layers, which are layer 101 and layer 102, which is deposited on the substrate, wherein the thickness of the metal oxide layer 101 ranges from 1 nm to 50 nm, and the thickness of the metal oxide layer 102 ranges from 10 nm to 2000 nm, wherein the metal oxide layer 101 or the The metal oxide layer 102 is selected from Al oxide, Cr oxide, Ni oxide, Ag oxide, Zr oxide or a combination thereof, but the two metal oxide layers are not the same; and, an Al ₂ O ₃ or The final top layer 105 of the mixture is located on two different metal oxide layers 101, 102. The mixture includes selected from Mg, Si, AF, Si oxide, Ti oxide, Cr oxide, Ni oxide, A substance of Ag oxide or Zr oxide, and the thickness of the top layer ranges from 20 nm to 200 nm. The substrate according to claim 7, wherein a metal oxide layer 103 is deposited on the two metal oxide layers 101, 102 to form three alternate metal oxide layers 101, 102, 103, wherein The metal oxide layer 103 is the same as the metal oxide layer 101, and the final top layer 105 is deposited on top of the layer 103 to form a multilayer, flexible and scratch resistant layer of the layers 101, 102, 103, and 105 Floor. The substrate according to claim 8, wherein another metal oxide layer 104 is deposited on the alternating three metal oxide layers 101, 102, 103 to form an alternating four metal oxide layers 101 , 102, 103, 104, wherein the metal oxide layer 104 is the same as the metal oxide layer 102, and the final top layer 105 is deposited on top of the layer 104 to form the layers 101, 102, 103, 104 and 105 multi-layer, flexible and scratch-resistant coating. The substrate according to claim 9, wherein, before depositing the final top layer 105, at least one of the alternating four metal oxide layers is further deposited to form the multilayer, flexible and scratch-resistant coating. The substrate according to claim 7, wherein the deposition is performed by a physical vapor deposition method including an electron beam evaporation deposition process or a sputter deposition process. The substrate according to claim 7, wherein the substrate comprises one or more of sapphire, quartz, fused silica, strengthened glass, tempered glass, metal, and/or plastic polymer, or any combination thereof, And wherein the plastic polymer includes polymethyl methacrylate, polycarbonate, polyethylene terephthalate or polyimide.

Images