Wafer, super lens, manufacturing method and application

Abstract

The invention discloses a wafer, a super lens, a manufacturing method and application, and the wafer for manufacturing the super lens comprises a substrate which is transparent to light in a specific operation bandwidth; the titanium oxide layer is formed on the surface of the substrate; the mask layer is formed on the surface of the titanium oxide layer, the surface of the mask layer comprises an opening area to be etched, and the area ratio of the opening area to the mask layer is larger than or equal to 7%; the mask layer contains a chromium element. By increasing the area ratio of the opening area of the mask layer to the mask layer, when the titanium oxide layer is etched, enough oxygen can be separated out from the titanium oxide layer, deposition of chloride of chromium is reduced, and the prepared super lens has higher refraction efficiency.

Description

Technical Field

[0001] The present invention relates to the field of optical elements, and in particular to a wafer, a super lens, a manufacturing method and uses thereof. Background Art

[0002] Metalenses, also known as super lenses, are two-dimensional flat lenses that use metasurfaces (flat two-dimensional metamaterials with sub-wavelength thickness) to focus light. The potential of metalenses to perform complex wavefront engineering in a single optical element is very attractive for a range of applications and is an ideal candidate to replace traditional lenses.

[0003] Titanium oxide is a dielectric material with a transparent window in the visible spectrum. Chromium has a high etching selectivity for titanium oxide. When etching titanium oxide on a substrate to prepare a superlens, chromium is often used as a mask. During the etching process, chromium is inevitably bombarded and deposited on the surface or grooves of the titanium oxide nanostructure, affecting the optical properties of the superlens. Summary of the invention

[0004] The object of the present invention is to provide a wafer, wherein a superlens processed from the wafer has excellent optical properties.

[0005] In order to achieve the above object, the present invention provides a wafer for making a superlens, comprising:

[0006] a substrate that is transparent to light within a specific operating bandwidth;

[0007] a titanium oxide layer formed on a surface of the substrate;

[0008] A mask layer is formed on the surface of the titanium oxide layer, the surface of the mask layer includes an opening area to be etched, and the area ratio of the opening area to the mask layer is greater than or equal to 7%; the mask layer contains chromium element.

[0009] Optionally, the mask layer includes: a chromium film layer formed on the surface of the titanium oxide layer, a hard mask layer formed on the surface of the chromium film layer, and a photoresist layer formed on the surface of the hard mask layer;

[0010] The photoresist layer includes the opening area.

[0011] Optionally, the chromium film layer is a chromium single substance film.

[0012] Optionally, the substrate is a glass substrate.

[0013] The present invention also provides a method for manufacturing a superlens, comprising:

[0014] A plasma processing device is provided, which includes a plasma processing chamber, wherein a radio frequency environment can be provided in the plasma processing chamber and an electrostatic chuck is arranged inside the chamber;

[0015] Providing a wafer for making a superlens as described above, and transferring the wafer onto the electrostatic chuck;

[0016] An etching gas is introduced into the plasma processing chamber, wherein the etching gas contains at least Cl2. The etching gas is dissociated into plasma under a radio frequency environment. The plasma etches the wafer to form the superlens.

[0017] Optionally, the step of plasma etching the wafer includes:

[0018] etching the titanium oxide layer to form a titanium oxide nanostructure;

[0019] The mask layer is removed to obtain a superlens.

[0020] Optionally, the mask layer includes: a chromium film layer formed on the surface of the titanium oxide layer, a hard mask layer formed on the surface of the chromium film layer, and a photoresist layer formed on the surface of the hard mask layer; the photoresist layer includes the opening area; and the step of plasma etching the wafer includes:

[0021] Using the photoresist layer as a mask, etching the hard mask layer so that the opening area is formed in the hard mask layer;

[0022] Using the hard mask layer as a mask, etching the chromium film layer so that the opening area is formed in the chromium film layer;

[0023] Using the chromium film layer as a mask, etching the titanium oxide layer to form the titanium oxide nanostructure;

[0024] The mask layer is removed to obtain a superlens.

[0025] Optionally, the etching gas further comprises: C x H y F z Gas, as an etching promoting gas, wherein 0<x≤4, y≥0, z≥0, y and z are not 0 at the same time.

[0026] Optionally, the C x H y F z The gas is C4F8.

[0027] Optionally, the C x H y F z In gases, x<2.

[0028] Optionally, the Cx H y F z The gas includes any one or more of CHF3, CH2F2, CH3F, CF4, and CH4.

[0029] Optionally, the etching gas further includes an inert gas to dilute the etching gas.

[0030] Optionally, the pressure in the plasma processing chamber is 8mT-15mT, the RF power is 1000w-3000w, the bias RF power is 100w-300w, the frequency is 300Hz-500Hz, and the temperature of the electrostatic chuck is 10°C-60°C.

[0031] Optionally, the flow rate of Cl2 is 100sccm-500sccm.

[0032] Optionally, C x H y F z The flow rate is 10sccm-100sccm.

[0033] Optionally, the flow rate of the inert gas is 50 sccm-800 sccm.

[0034] The present invention also provides a super lens, which is made by the above-mentioned manufacturing method.

[0035] The present invention also provides a use of a superlens, wherein the superlens is made by the above-mentioned manufacturing method, and the superlens is used for an optical element.

[0036] Optionally, the metalens is used for VR and AR lenses.

[0037] The beneficial effects of the present invention are:

[0038] The present invention finds that when etching an existing wafer into a superlens, due to the chromium element contained in the mask layer, the chromium is precipitated from the mask layer under the bombardment of plasma, reacts with the chlorine in the etching gas to generate chromium chloride, which is deposited in the superlens, resulting in unsatisfactory refractive efficiency of the superlens. The present invention utilizes the principle that oxygen and chlorine can simultaneously react with chromium to obtain gaseous products, creatively proposes to use a titanium oxide layer as an oxygen source, and increases the area of ​​the exposed titanium oxide layer by increasing the area ratio of the mask layer opening area to the mask layer, so that when etching the titanium oxide layer, enough oxygen elements can be precipitated from the titanium oxide layer to participate in the reaction of chromium and chlorine, thereby reducing the deposition of chromium chloride, and preparing a superlens with higher refractive efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1A schematic structural diagram of a wafer for making a superlens provided by the present invention.

[0040] Figure 2 for Figure 1 Schematic diagram of the structure of the metalens made of wafer.

[0041] Figure 3 A flow chart of a method for manufacturing a superlens provided by the present invention.

[0042] Figure 4 A schematic diagram of the structure of another wafer for making a superlens provided by the present invention.

[0043] Figure 5 To etch layer by layer using the manufacturing method provided by the present invention Figure 4 Schematic diagram of the wafer etching process structure.

[0044] Figure 6 is a photograph of a superlens made using a wafer with an area ratio of the opening area to the mask layer of 50%, wherein: Figure 6 (a) is a scanning electron microscope image of titanium oxide nanostructure. Figure 6 (b) is a schematic diagram of the distribution of chlorine elements in titanium oxide nanostructures. Figure 6 (c) is a schematic diagram of the distribution of chromium elements in titanium oxide nanostructures.

[0045] In the figure, 100-substrate, 200-titanium oxide layer, 201-titanium oxide nanostructure, 300-mask layer, 301-mask column, 302-opening area, 310-chromium film layer, 311-chromium film column, 320-hard mask layer, 321-hard mask column, 330-photoresist layer, 331-photoresist column. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0048] A superlens is an optical metasurface that realizes the function of lens imaging. It controls parameters such as the phase and amplitude of the incident light based on sub-wavelength artificial structural units to achieve the function of lens focusing or imaging. Therefore, the superlens is required to be transparent to light within a specific operating bandwidth. Titanium oxide is a dielectric material with a transparent window in the visible spectrum. The superlens obtained by arranging titanium dioxide in a specific pattern on a substrate can work effectively in the visible light range and has broad application prospects.

[0049] Before making a superlens, a titanium oxide layer and a mask layer are deposited on the substrate in sequence to obtain wafer A. The mask layer includes an opening area to be etched, that is, the mask layer only covers a specific area of ​​the titanium oxide layer, and the titanium oxide layer covered by the mask layer will not be etched, and a patterned titanium oxide layer can be formed in the end. At this time, the titanium oxide layer is composed of a number of columnar titanium oxide nanostructures arranged in an array. After the titanium oxide nanostructure is formed, the mask layer is removed by other processes to obtain a superlens.

[0050] After the existing etching process is completed, the refraction efficiency of visible light in the super lens is still not ideal. The inventors have found that after the etching is completed, there are deposits containing chromium and chlorine on the top and side walls of the titanium oxide nanostructure. The inventors analyzed that the formation mechanism may be: because chromium has a higher etching selectivity for titanium oxide, the mask layer contains chromium, and the etching gas contains chlorine. Under the bombardment of chlorine, the chromium in the mask layer reacts with the chlorine as shown in formula (1) and formula (2):

[0051] Cl2+Cr→CrCl3(↓)(1)

[0052] Cl2+Cr→CrCl2(↓)(2)

[0053] According to formula (1) and formula (2), after chromium reacts with chlorine, chromium dichloride and chromium trichloride are generated. These sediments will adhere to the top, sidewalls and grooves between adjacent titanium dioxide nanostructures of the titanium oxide nanostructure. As analyzed above, the presence of each element in the titanium oxide nanostructure will affect the optical performance of the super lens. Therefore, how to reduce the deposition of chromium chloride on the titanium oxide nanostructure is the key to improving the refractive efficiency of the super lens.

[0054] Although chromium reacts with chlorine alone to form deposits such as chromium dichloride and chromium trichloride, if chromium reacts with chlorine and oxygen at the same time, CrO2Cl2 gas can be generated and evaporated from the wafer, as shown in formula (3):

[0055] Cl2+O2+Cr→CrO2Cl2(↑)(3)

[0056] However, in addition to chlorine, the etching gas also includes carbon-containing gases (including carbon fluorine gas or carbon hydrogen fluorine gas). If oxygen is directly added to the etching gas, the oxygen may preferentially react with the carbon-containing gas in the etching gas on the surface of the wafer. Since etching is usually carried out from the surface of the wafer to the inside of the wafer, the chromium in the mask layer falls toward the titanium oxide layer after being bombarded and falls into the inside of the wafer. However, the oxygen in the etching gas has been consumed by the carbon-containing gas before entering the inside of the wafer and reacting with the chromium, so it is difficult for the oxygen in the etching gas to contact and react with the chromium. Therefore, in order to reduce the deposition of chromium chloride, it is necessary to find a suitable oxygen source separately.

[0057] The inventor unexpectedly discovered that as etching proceeds, oxygen atoms in the titanium oxide layer are also bombarded by the high-energy etching gas and precipitated from the titanium oxide layer; and the amount of oxygen atoms precipitated is related to the area of ​​the titanium oxide layer exposed to the etching gas environment. The larger the exposed area of ​​the titanium oxide layer, the greater the amount of oxygen atoms precipitated, and the easier it is for the oxygen atoms to come into contact with the chromium that is bombarded and dropped, and react with the chlorine in the etching gas as shown in formula (3), rather than being consumed by the carbon-containing gas on the wafer surface.

[0058] In order to further verify the relationship between the amount of oxygen atoms precipitated and the deposition of chromium chloride, a silicon-containing layer without oxygen was deposited on the substrate to obtain wafer B. A mask layer was deposited on the silicon-containing layer, the same opening area was processed on the mask layer, and the silicon-containing layer was etched to form a columnar silicon nanostructure on the substrate surface. There were deposits containing chromium and chlorine elements on the top and sidewalls of the silicon nanostructure.

[0059] Compared with the titanium oxide nanostructure obtained after etching wafer A, the silicon nanostructure obtained after etching wafer B has a wider bottom width, indicating that there are more deposits on the sidewalls of the silicon nanostructure; more chlorine and chromium elements are deposited on the top and sidewalls of the silicon nanostructure. The above proves that when the amount of oxygen atoms precipitated decreases, the deposition of chromium chloride increases.

[0060] Using the above findings, the present invention has developed a wafer for making a superlens, which has a larger opening area so that the exposed area of ​​the titanium oxide layer is larger, more oxygen atoms can be precipitated, and chromium contamination during the etching process is reduced.

[0061] like Figure 1As shown, the present invention provides a wafer for making a superlens, comprising: a substrate 100, the substrate 100 is transparent to light within a specific operating bandwidth, and optionally, the substrate is a glass substrate, which is transparent in the visible light range (wavelength 390nm-780nm); a titanium oxide layer 200, the titanium oxide layer 200 is formed on the surface of the substrate 100; and a mask layer 300, the mask layer 300 is formed on the surface of the titanium oxide layer 200. Since chromium has a higher etching selectivity to titanium oxide, the mask layer 300 contains chromium elements. In order to form a Figure 2 The columnar titanium oxide nanostructure 201 shown is patterned on the surface of the mask layer 300, that is, the mask layer 300 includes a plurality of mask columns 301, the mask columns 301 are located on the surface of the mask layer 300, and the area between two adjacent mask columns 301 is used as an opening area 302 to be etched. The etching gas enters the opening area 302, and along the thickness direction of the mask layer 300, etches the portion of the titanium oxide layer 200 corresponding to the opening area 302, and the pattern set on the surface of the mask layer 300 is transferred to the titanium oxide layer 200, forming a columnar titanium oxide nanostructure 201 on the titanium oxide layer 200. Then, the mask layer 300 is removed. The larger the area of ​​the opening area 302 is, the larger the area of ​​the titanium oxide layer 200 exposed to the etching gas when etching the titanium oxide layer 200, and the more oxygen atoms are precipitated from the titanium oxide layer 200. After multiple experimental adjustments, the inventors found that when the area ratio of the opening region 302 to the mask layer 300 is greater than or equal to 7%, the amount of oxygen atoms precipitated is sufficient to consume the chromium chloride into gas, thereby ensuring the performance of the superlens. Therefore, in the wafer for making a superlens provided by the present invention, the area ratio of the opening region 302 to the mask layer 300 is greater than or equal to 7%.

[0062] It should be noted that the present invention only limits the area ratio of the opening region 302 to the mask layer 300 to be greater than or equal to 7%, and no longer limits the size of the titanium oxide nanostructure in the superlens, and the upper limit of the area of ​​the opening region 302 and the mask layer 300. It is easy to understand that when the area of ​​the opening region is too large, the area of ​​the oxidized nanostructure will be correspondingly reduced. Therefore, those skilled in the art can reasonably design a superlens that meets the imaging requirements according to the imaging principle of the superlens to realize the function of the superlens focusing light.

[0063] like Figure 3 As shown, the present invention also provides a method for manufacturing a superlens, comprising:

[0064] Step S1, providing a plasma processing device.

[0065] The plasma processing device may be an inductively coupled plasma (ICP) reaction device or a capacitively coupled plasma (CCP) reaction device. The plasma processing device comprises a plasma processing chamber, wherein a radio frequency environment is provided in the plasma processing chamber and an electrostatic chuck is arranged inside the chamber. The radio frequency environment is used to provide plasma. The electrostatic chuck is also provided with an adsorption electrode, and a voltage can be applied to the adsorption electrode.

[0066] Step S2, transferring the wafer for making the superlens onto the electrostatic chuck.

[0067] The wafer includes a substrate 100, a titanium oxide layer 200 formed on the surface of the substrate 100, and a mask layer 300 formed on the surface of the titanium oxide layer 200, wherein the mask layer 300 contains chromium. A plurality of mask pillars 301 are arranged on the mask layer 300, and an opening area 302 to be etched is formed between two adjacent mask pillars 301, and an area ratio of the opening area 302 to the mask layer 300 is greater than or equal to 7%.

[0068] Step S3, introducing etching gas into the plasma processing chamber.

[0069] The etching gas at least contains Cl2, and the etching gas dissociates into plasma under a radio frequency environment. The plasma etches the wafer to form the superlens.

[0070] In some embodiments, the step of plasma etching the wafer includes: etching the titanium oxide layer to form a titanium oxide nanostructure; and then removing the mask layer to obtain a super lens.

[0071] In some embodiments, the etching gas further comprises: C x H y F z Gas, as an etching promoting gas, wherein 0<x≤4, y≥0, z≥0, y and z are not 0 at the same time; Optionally, the C x H y F z The gas is C4F8. x H y F z The shorter the carbon chain of the gas, the lower the sensitivity of the wafer to temperature. Optionally, x < 2, the C x H y F z The gas includes any one or more of CHF3, CH2F2, CH3F, CF4, and CH4.

[0072] In some embodiments, the etching gas further includes an inert gas to dilute the etching gas.

[0073] In some embodiments, the pressure in the plasma processing chamber is 8mT-15mT, the RF power is 1000w-3000w, the frequency is 60MHz, the bias RF power is 100w-300w, the frequency is 300Hz-500Hz, and the temperature of the electrostatic chuck is 10℃-60℃.

[0074] In some embodiments, the flow rate of Cl2 is 100 sccm-500 sccm, C x H y F z The flow rate of the inert gas is 10sccm-100sccm, and the flow rate of the inert gas is 50sccm-800sccm.

[0075] like Figure 4 As shown, the present invention also provides another wafer for making a superlens, comprising: a substrate 100, the substrate 100 is transparent to light within a specific operating bandwidth, and optionally, the substrate is a glass substrate, which is transparent in the visible light range; a titanium oxide layer 200, the titanium oxide layer 200 is formed on the surface of the substrate 100; a mask layer 300, the mask layer 300 is formed on the surface of the titanium oxide layer 200. The mask layer 300 comprises: a chromium film layer 310 formed on the surface of the titanium oxide layer 200, a hard mask layer 320 formed on the surface of the chromium film layer 310, and a photoresist layer 330 formed on the surface of the hard mask layer 320. In some embodiments, the hard mask layer 320 is a bottom anti-reflection layer, and the chromium film layer 310 is a chromium single substance film.

[0076] In order to form the columnar titanium oxide nanostructure 201, the surface of the photoresist layer 330 is patterned, and a plurality of photoresist columns 331 are arranged on the surface of the photoresist layer 330. The area between two adjacent photoresist columns 331 is used as an opening area 302 to be etched, and the area ratio of the opening area 302 to the photoresist layer 330 is greater than or equal to 7%. The etching gas enters the opening area 302, and sequentially etches the hard mask layer 320, the chromium film layer 310 and the titanium oxide layer 200 corresponding to the opening area 302 along the thickness direction of the photoresist layer 330. The pattern arranged on the surface of the photoresist layer 330 is finally transferred to the titanium oxide layer 200, and the columnar titanium oxide nanostructure 201 is formed on the titanium oxide layer 200.

[0077] In order to Figure 4 The wafer shown is etched into a superlens, such as Figure 5 As shown, in the method for manufacturing a superlens provided by the present invention, in step S3, the step of plasma etching the wafer further includes:

[0078] S3.1: The area between two adjacent photoresist pillars 331 serves as the opening area 302 to be etched. The etching gas enters the opening area 302 and etches the portion of the hard mask layer 320 corresponding to the opening area 302 along the thickness direction of the photoresist layer 330 using the photoresist layer 330 as a mask. The pattern set on the surface of the photoresist layer 330 is transferred to the hard mask layer 320, and a hard mask pillar 321 is formed on the hard mask layer 320.

[0079] S3.2: The area between two adjacent hard mask pillars 321 is used as the opening area 302 to be etched. The hard mask layer 320 is used as a mask to etch the portion of the chrome film layer 310 corresponding to the opening area 302 , and the pattern on the surface of the hard mask layer 320 is transferred to the chrome film layer 310 , forming a chrome film pillar 311 on the chrome film layer 310 .

[0080] S3.3: The area between two adjacent chromium film pillars 311 is used as the opening area 302 to be etched. The chromium film layer 310 is used as a mask to etch the portion of the titanium oxide layer 200 corresponding to the opening area 302, and the pattern on the surface of the chromium film layer 310 is transferred to the titanium oxide layer 200, forming a columnar titanium oxide nanostructure 201 on the titanium oxide layer 200.

[0081] When plasma etches the titanium oxide layer 200 , the sidewalls of the chromium film pillars 311 are inevitably bombarded, causing the chromium atoms to fall toward the titanium oxide layer 200 after being bombarded, and tend to react with chlorine to form deposits. However, since the wafer provided by the present invention has an area ratio of the opening region 302 to the photoresist layer 330 that is greater than or equal to 7%, the pattern formed on the photoresist layer 330 will be transferred to the hard mask layer 320 and the chrome film layer 310 in sequence. Therefore, in step S3.2, after the chrome film pillar 311 is formed on the chrome film layer 310, the area ratio of the opening region 302 to the chrome film layer 310 is also greater than or equal to 7%. The portion of the titanium oxide layer 200 corresponding to the opening region 302 is exposed to the plasma environment, so that when the plasma bombards the titanium oxide layer 200, sufficient oxygen atoms can be precipitated from the titanium oxide layer 200. The oxygen atoms contact the chlorine in the etching gas and react with the fallen chromium atoms in the reaction of formula (3) to generate gaseous CrO2Cl2, which greatly reduces the formation of solid deposits on the top and side walls of the titanium oxide nanostructure 201 and in the grooves between adjacent titanium dioxide nanostructures.

[0082] S3.4: removing the mask layer 300 to obtain a superlens.

[0083] In some embodiments, between step S3.2 and step S3.3, a step of removing the photoresist layer 330 and the hard mask layer 320 remaining on the top surface of the chrome film column 311 is also included; at this time, in step S3.4, removing the mask layer 300 includes removing the chrome film layer 310.

[0084] The metalens prepared by the present invention has the advantages of thinner volume, lighter weight, lower cost, better imaging, and easier integration. It provides a solution for compact integrated optical systems and can be used for optical elements, such as VR and AR lenses.

[0085] Example

[0086] A wafer C for making a superlens is provided, comprising: a substrate 100, which is a glass substrate; a titanium oxide layer 200, which is formed on the surface of the substrate 100; and a mask layer 300, which is formed on the surface of the titanium oxide layer 200. The mask layer 300 comprises: a chromium film layer 310 formed on the surface of the titanium oxide layer 200, a hard mask layer 320 formed on the surface of the chromium film layer 310, and a photoresist layer 330 formed on the surface of the hard mask layer 320. The hard mask layer 320 is an amorphous carbon layer, and the chromium film layer 310 is a chromium single substance film. A plurality of photoresist columns 331 are arranged on the surface of the photoresist layer 330, and the area between two adjacent photoresist columns 331 is used as an opening area 302 to be etched, and the area ratio of the opening area 302 to the photoresist layer 330 is 50%.

[0087] The wafer C of this embodiment is made into a superlens, including:

[0088] S1, providing a plasma processing device.

[0089] The plasma processing equipment is an inductively coupled plasma (ICP) reaction device. The plasma processing equipment includes a plasma processing chamber, in which a radio frequency environment can be provided and an electrostatic chuck is arranged inside. The radio frequency environment is used to provide plasma. The electrostatic chuck is also provided with an adsorption electrode, and a voltage can be applied to the adsorption electrode.

[0090] S2, transferring the wafer for making the superlens onto the electrostatic chuck.

[0091] S3, introducing etching gas into the plasma processing chamber.

[0092] The etching gas comprises Cl2, CH3F and He, and the etching gas is dissociated into plasma under a radio frequency environment. The steps of etching the wafer with the plasma include:

[0093] S3.1: The area between two adjacent photoresist pillars 331 serves as the opening area 302 to be etched. The etching gas enters the opening area 302 and etches the portion of the hard mask layer 320 corresponding to the opening area 302 along the thickness direction of the photoresist layer 330 using the photoresist layer 330 as a mask. The pattern set on the surface of the photoresist layer 330 is transferred to the hard mask layer 320, and a hard mask pillar 321 is formed on the hard mask layer 320.

[0094] S3.2: The area between two adjacent hard mask pillars 321 is used as the opening area 302 to be etched. The hard mask layer 320 is used as a mask to etch the portion of the chrome film layer 310 corresponding to the opening area 302 , and the pattern on the surface of the hard mask layer 320 is transferred to the chrome film layer 310 , forming a chrome film pillar 311 on the chrome film layer 310 .

[0095] S3.3: removing the photoresist layer 330 and the hard mask layer 320 remaining on the top surface of the chrome film pillar 311 .

[0096] S3.4: The area between two adjacent chromium film pillars 311 is used as the opening area 302 to be etched. The chromium film layer 310 is used as a mask to etch the portion of the titanium oxide layer 200 corresponding to the opening area 302, and the pattern on the surface of the chromium film layer 310 is transferred to the titanium oxide layer 200, forming a columnar titanium oxide nanostructure 201 on the titanium oxide layer 200.

[0097] When etching the titanium oxide layer, the pressure in the plasma processing chamber is 10mT, the power of the RF power source is 2000W, the power of the bias RF power source is 250W, the temperature of the electrostatic chuck is 40°C, the flow rate of Cl2 is 300sccm, which is used to etch the titanium oxide layer; the flow rate of CH3F is 30sccm, which is used as an etching gas; the flow rate of He is 400sccm, which is used to dilute the etching gas and adjust the uniformity of gas distribution.

[0098] S3.5: Remove the chromium film layer 310 to obtain a super lens.

[0099] The existing wafer A used to make superlenses has an area ratio of its opening area to the mask layer that is less than 7%; the wafer C provided in this embodiment has an area ratio of its opening area to the mask layer that is 50%; the two differ only in the area ratio of the opening area to the mask layer.

[0100] The titanium oxide nanostructure of the superlens produced in this embodiment is as follows Figure 6 Compared with the titanium oxide nanostructure obtained after etching wafer A, the titanium oxide nanostructure obtained after etching wafer C has more vertical sidewalls and narrower bottom width, indicating that there is less deposit on the sidewall of the titanium oxide nanostructure in this embodiment. Figure 6 In (b), the fluorescent part is the distribution of chlorine in the titanium oxide nanostructure. Figure 6 In (c), the fluorescent part is the distribution of chromium in the titanium oxide nanostructure. Figure 6The fluorescent area of ​​(b) and (c) is smaller, indicating that the content of chlorine and chromium in the top and sidewall of the titanium oxide nanostructure in this embodiment is reduced. Therefore, this embodiment can effectively reduce the formation of chromium chloride deposition and improve the optical performance of the super lens by increasing the area of ​​the opening area on the mask layer.

[0101] In summary, a wafer, a superlens, a manufacturing method and a use are provided, wherein the wafer for manufacturing the superlens comprises a substrate, a titanium oxide layer and a mask layer, the surface of the mask layer comprises an opening area to be etched, and the mask layer contains a chromium element. When etching the titanium oxide layer, since the chromium will inevitably be bombarded and react with chlorine to generate a deposit, the wafer provided by the present invention has an area ratio of the opening area to the mask layer of greater than or equal to 7%. When etching the titanium oxide layer, under the bombardment of plasma, sufficient oxygen can be precipitated from the titanium oxide layer, and the oxygen and chlorine react with chromium together to generate a gaseous product, reducing the deposition of chromium chloride, and the prepared superlens has a higher refractive efficiency.

[0102] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A wafer for making a superlens, characterized in that: include: a substrate that is transparent to light within a specific operating bandwidth; a titanium oxide layer formed on a surface of the substrate; A mask layer, wherein the mask layer is formed on a surface of the titanium oxide layer, the surface of the mask layer includes an opening area to be etched, and an area ratio of the opening area to the mask layer is greater than or equal to 7%; The mask layer contains chromium element.

2. The wafer for making a superlens according to claim 1, characterized in that: The mask layer includes: a chromium film layer formed on the surface of the titanium oxide layer, a hard mask layer formed on the surface of the chromium film layer, and a photoresist layer formed on the surface of the hard mask layer; The photoresist layer includes the opening area.

3. The wafer for making a superlens according to claim 2, characterized in that: The chromium film layer is a chromium single substance film.

4. The wafer for making a superlens according to claim 1, characterized in that: The substrate is a glass substrate.

5. A method for manufacturing a metalens, characterized in that: include: A plasma processing device is provided, which includes a plasma processing chamber, wherein a radio frequency environment can be provided in the plasma processing chamber and an electrostatic chuck is arranged inside the chamber; Providing a wafer for making a superlens according to any one of claims 1 to 4, and transferring the wafer onto the electrostatic chuck; An etching gas is introduced into the plasma processing chamber, wherein the etching gas contains at least Cl2. The etching gas is dissociated into plasma under a radio frequency environment. The plasma etches the wafer to form the superlens.

6. The method for manufacturing a superlens according to claim 5, wherein: The step of plasma etching the wafer comprises: etching the titanium oxide layer to form a titanium oxide nanostructure; The mask layer is removed to obtain a superlens.

7. The method for manufacturing a superlens according to claim 6, wherein: The mask layer includes: a chromium film layer formed on the surface of the titanium oxide layer, a hard mask layer formed on the surface of the chromium film layer, and a photoresist layer formed on the surface of the hard mask layer; the photoresist layer includes the opening area; The step of plasma etching the wafer comprises: Using the photoresist layer as a mask, etching the hard mask layer so that the opening area is formed in the hard mask layer; Using the hard mask layer as a mask, etching the chromium film layer so that the opening area is formed in the chromium film layer; Using the chromium film layer as a mask, etching the titanium oxide layer to form the titanium oxide nanostructure; The mask layer is removed to obtain a superlens.

8. The method for manufacturing a superlens according to any one of claims 5 to 7, characterized in that: The etching gas further comprises: C x H y F z Gas, as an etching promoting gas, wherein 0<x≤4, y≥0, z≥0, y and z are not both 0.

9. The method for manufacturing a superlens according to claim 8, wherein: The C x H y F z The gas is C4F8.

10. The method for manufacturing a superlens according to claim 9, wherein: The C x H y F z In gases, x<2.

11. The method for manufacturing a superlens according to claim 10, wherein: The C x H y F z The gas includes any one or more of CHF3, CH2F2, CH3F, CF4, and CH4.

12. The method for preparing a metalens according to any one of claims 5 to 7, characterized in that: The etching gas also includes an inert gas.

13. The method for manufacturing a superlens according to any one of claims 5 to 7, characterized in that: The pressure in the plasma processing chamber is 8mT-15mT, the RF power is 1000w-3000w, the bias RF power is 100w-300w, the frequency is 300Hz-500Hz, and the temperature of the electrostatic chuck is 10°C-60°C.

14. The method for manufacturing a superlens according to any one of claims 5 to 7, characterized in that: The flow rate of Cl2 is 100sccm-500sccm.

15. The method for manufacturing a superlens according to claim 8, wherein: C x H y F z The flow rate is 10sccm-100sccm.

16. The method for manufacturing a superlens according to claim 12, wherein: The flow rate of the inert gas is 50 sccm-800 sccm.

17. A superlens, characterized in that: The superlens is made by the manufacturing method described in any one of claims 5-16.

18. A use of a metalens, characterized in that: The superlens is made by the manufacturing method described in any one of claims 5 to 16, and the superlens is used for an optical element.

19. The use of the metalens according to claim 18, characterized in that: The super lens is used for VR and AR lenses.

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