Improved method for increasing resolution of lithography

Abstract

An improved method for increasing the resolution of lithography. In the present invention, a light storage unit is arranged between an objective lens and a wafer; during exposure, after passing through a lens system, signal light is temporarily stored in the light storage unit in the form of an atomic spin wave, and the energy of the light is converted into energy for medium atoms of the light storage unit; subsequently, stored light information may be released according to an original direction, and can be regarded as one ideal point light source, and the point light source is propagated in the original direction. Since a propagation path is not limited by the aperture of a lens, an effective aperture is increased, a corresponding Airy disk is reduced, and the minimum resolvable size can be reduced. When the point light source reaches the wafer, the width of the Airy disk is narrowed, and the resolution of lithography is significantly increased, thereby achieving the benefits of reducing the requirement for the aperture of the lithography. In order to meet the resolution requirements, a lens imaging system can use a small aperture, which implicitly reduces the manufacturing difficulty and cost.

Description

Improvement 4: A method for improving the resolution of lithography machines Technical Field

[0001] The present invention relates to the technical field of photolithography machines, and in particular to an improved method for improving the resolution of a photolithography machine. Background Art

[0002] In the field of chip manufacturing, lithography machines (also known as mask alignment exposure machines, exposure systems, lithography systems, etc.) are very critical equipment. They use optical projection imaging technology to transfer the pattern on the photomask (also known as the photomask) onto the wafer, which is the key to achieving mass production of chips.

[0003] With the development of the chip industry, the same chip area needs to accommodate more and more components and wiring, and the resolution of photolithography machines needs to be continuously improved. In optical projection imaging, the diffraction limit of light is a major factor limiting resolution improvement. The diffraction limit refers to the fact that when an ideal object point is imaged by an optical system, due to the limitation of diffraction, the ideal image point is not obtained. Instead, a Fraunhofer diffraction image is obtained, the so-called Airy disk (diffuse spot). This is a key factor affecting the resolution of optical projection imaging systems. In optical imaging, two object points are imaged as two diffuse spots. If they are too close, they are difficult to distinguish. The larger the diffuse spot, the lower the resolution. In the same optical system, the smaller the wavelength of light, the smaller the diffuse spot and the higher the resolution. Therefore, reducing the wavelength of the photolithography light source can improve the resolution of the photolithography machine.

[0004] The evolution of the wavelength of the lithography light source:

[0005] When the wavelength was reduced to 193nm, further engineering became increasingly difficult because light was easily absorbed. The existing lenses, photoresists, and other supporting materials were no longer usable and had to be completely redeveloped. Therefore, at 193nm, engineers developed a new technical solution: immersion lithography. When light propagates through water, the refractive index of water is greater than that of air, thus shortening the wavelength. Using this solution, the wavelength of the light source can be shortened from 193nm to 132nm. Immersion lithography proved very effective and remains a widely used and successful solution.

[0006] To manufacture chips below 5 nanometers, the chip industry generally believes that the wavelength of the light source requires EUV. EUV has a wavelength of 13.5nm, classifying it as extreme ultraviolet light. However, it is no longer strictly optical radiation, but rather a soft X-ray. Currently, no optical material can refract it, and even air absorbs it. Therefore, the EUV lithography machine must be vacuum-evacuated. The EUV optical path system utilizes mirrors coated with multi-layer molybdenum-silicon interference optical films, rather than refractive lenses. This makes engineering implementation extremely challenging. Currently, there is only one manufacturer of EUV lithography machines, AXML of the Netherlands, and they are currently unavailable in China.

[0007] We have a deep understanding of the underlying physical laws and thinking, and have developed innovative technical routes, which greatly reduce the technical difficulty and provide excellent performance.

[0008] The inventor has filed the following Chinese patent applications on the same subject:

[0009] Patent 1 (Title: A method for improving the resolution of a photolithography machine; Application number: 2023109064718; Application date: 20230724)

[0010] Patent 2 (Title: Improved Method for Improving the Resolution of a Photolithography Machine; Application Number: 202311159318X; Application Date: 20230910; Patent Number: ZL 2023 1 1159318.X; Authorization Announcement Date: July 2, 2024)

[0011] This invention application has made some technical improvements based on the above-mentioned Patent 2. Since there are many connections between the two, this invention application retains part of the content of Patent 2. For ease of reading, the improved parts in this invention application are specially marked: "The improved part of this invention application begins" and "The improved part of this invention application ends".

[0012] Summary of the Invention

[0013] The present invention demonstrates a new technical solution for improving the resolution of a photolithography machine.

[0014] The first part of the improvement of the present invention application

[0015] In subsequent research, we discovered that while the patented method resolves interference between different photons, even a single photon, when passing through an optical system with a certain aperture, is still subject to the Rayleigh criterion for its inherent Airy disk. An ideal point light source passing through an aperture with a diameter of D, such as a small hole or a lens system, will undergo diffraction, resulting in an Airy disk. Because of the Airy disk, the minimum resolvable angle is calculated using the following formula:

[0016] In the formula, λ is the frequency of the point light source, and D is the diameter of the aperture.

[0017] The resolution of the lithography machine is limited by the Rayleigh criterion, and the minimum resolvable size of the lithography machine is calculated by the following formula:

[0018] Where λ is the wavelength of light, K1 is the process coefficient factor, NA is the numerical aperture of the lithography objective lens, NA = n.sinθ, n is the refractive index, that is, the refractive index of the medium between the wafer and the lens. If it is air, its refractive index is close to 1.0. If it is a vacuum, its refractive index is 1.0. Immersion lithography machines use transparent liquids with high refractive index, such as deionized water, whose refractive index is 1.46.

[0019] θ represents the angle of incidence.

[0020] To achieve the smallest possible minimum resolvable dimension, current lithography machines use a method 1: increasing the aperture. Consequently, the lenses used in current lithography machines are very large, which inadvertently increases manufacturing difficulty and cost. Method 2: immersion, using a high-refractive-index medium between the wafer and the lens, such as deionized water. Its refractive index n is 1.46, approximately 1.46 times that of air and a vacuum.

[0021] [Corrected 02.08.2024 according to Rule 26] This application utilizes the electromagnetically induced transparency (EIT) effect. The frequency of the probe light (also known as the signal light) corresponds to the absorption transition frequency of the medium. When the probe light (also known as the signal light) is incident on the medium alone, it cannot pass through the medium due to the medium's strong resonant absorption of this frequency. A second strong control light beam (also known as coupled light) forms a three-level atomic system with the probe light. When the strong control light is present, the strong control light field causes quantum coherent interference, and the probe light passes through the medium with almost no absorption. This is electromagnetically induced transparency (EIT), resulting in a sharp change in the refractive index of the medium (see Figure 12 of the specification), which slows the group velocity of the probe light. By changing the intensity of the control light, the group velocity of the detection light can be controlled. The lower the intensity of the control light, the slower the group velocity of the detection light. When the control light is adiabatically turned off, the group velocity of the detection light becomes 0, that is, the detection light is saved to the medium in the form of atomic spin waves, and the optical information is stored in the medium. This is called the optical writing process, and the control light of this process is called the writing light. The process of reading out the stored optical information is called the optical reading process, and the control light of this process is called the reading light. When the reading light is turned on again, if the frequency and direction of the reading light are the same as those of the writing light, the stored optical information will be released according to the original frequency and direction. If the frequency and direction of the reading light are different from those of the writing light, the stored optical information will be released according to the new frequency and new direction.

[0022] [Corrected 02.08.2024 according to Rule 26] Optical storage can be achieved by detecting light, controlling writing light and reading light according to the timing of Figure 1.

[0023] [Corrected 02.08.2024 according to Rule 26] If the detection light and the control light follow the timing of Figure 2, slow light can be achieved.

[0024] Method 1 of the present application is to place an optical storage unit between an objective lens and a wafer, and control the timing of control light and detection light. During exposure, the detection light passes through the lens system and is temporarily stored in the optical storage unit in the form of atomic spin waves. The energy of the light is converted into the energy of the atoms in the medium of the optical storage unit, and then restored to light according to the original propagation direction. The process of light restoration is to convert the energy of the atoms in the medium of the optical storage unit into the energy of light. If the frequency and direction of the read light are the same as those of the write light, the stored optical information will be released according to the original frequency and direction; if the frequency and direction of the read light are different from those of the write light, the stored optical information will be released according to the new frequency and new direction. After the stored light information is released, it can be regarded as a newly generated ideal point light source. This point light source propagates in the direction of generation. In this application, it will propagate in the original direction before writing. Since the propagation path is not limited by the lens aperture, the effective aperture becomes larger, the corresponding Airy disk becomes smaller, and the minimum resolvable size will decrease. When this point light source reaches the wafer, the Airy disk width becomes narrower, and the resolution of the lithography machine is greatly improved. The benefit of this is that the aperture requirements for the lithography machine can be reduced. In order to achieve the same resolution requirements, the lens imaging system can adopt a small aperture, which invisibly reduces the difficulty and cost of manufacturing.

[0025] [Corrected 02.08.2024 according to Rule 26] Method 2 of the present application is to place a light slow-light unit between the objective lens and the wafer. During exposure, after the detection light passes through the lens system, in the light slow-light unit, because its frequency corresponds to the absorption transition frequency of the medium, when it is incident on the medium alone, the detection light cannot pass through the medium due to the medium's strong resonant absorption of this frequency. Another beam of strong control light (also called coupled light) forms a three-level atomic system with the probe light. When the strong control light is present, the strong control light field causes quantum coherent interference, and the probe light is almost not absorbed when passing through the medium, that is, electromagnetic induced transparency (EIT) occurs, and the refractive index of the medium changes dramatically (see Figure 12 of the specification), thereby causing the group velocity of the probe light to slow down. Here, our focus is on the refractive index of the medium. When a specific probe light frequency is selected, the group velocity of the probe light when passing through the medium slows down, the equivalent wavelength of the probe light becomes shorter, and the refractive index of the medium increases significantly, and the medium becomes a superrefractive medium with a large refractive index. Just like the working mechanism of an immersion lithography machine, the optical slow light unit narrows the width of the Airy disk, reduces the minimum resolvable size of the lithography machine, and improves the resolution.

[0026] End of the Improvement Part 1 of the present invention application

[0027] The present invention will be further described below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [Corrected 02.08.2024 according to Rule 26] Figure 1 is an operating timing diagram of the optical storage unit. Incident detection light refers to detection light before light is stored in the medium (414), outgoing detection light (415) refers to detection light restored after light is stored in the medium, and outgoing detection light (415) is detection light received by the photoresist (3102). Writing light refers to control light (416) for storing the detection light in the medium. Reading light and reading light 2 refer to control light (416) for restoring the detection light stored in the medium. The difference between these two reading lights is that the amplitude of the reading light and the writing light is the same, while the amplitude of the reading light 2 is greater than the amplitude of the writing light. The reading light, reading light 2, and writing light are all control light (416). They are subdivided according to different functions. The optical switch signal refers to the switch control signal of the optical switch (417, shown in Patent 2). The opening and closing of the optical switch (417) are controlled by the optical switch signal. The horizontal axis of the curve in the figure represents time, and the vertical axis represents the intensity of light. T1-T8 represent the relevant nodes on the time axis in the figure.

[0029] At time T1, the write light is turned on. A certain time later, at time T2, the incident probe light is turned on. Because the write light acts as the control light, the electromagnetically induced transparency (EIT) effect occurs, allowing the incident probe light to propagate through the medium. Due to the slow-light effect, its group velocity in the medium is lower than the speed of light in a vacuum. At time T3, the write light is turned off, eliminating its role as the control light. The incident probe light's propagation through the medium ceases and is stored in the medium. At time T4, the read light is turned on. Because the read light acts as the control light, the incident probe light, once stored in the medium, is restored as the outgoing probe light and continues to propagate. Due to the slow-light effect, its group velocity in the medium is lower than the speed of light in a vacuum. When the read light is replaced by read light 2, the restored outgoing probe light is accelerated because its amplitude is greater than the original read light, resulting in a temporal compression of the outgoing probe light pulse. If the amplitude of read light 2 is smaller than the original read light, the opposite effect occurs, causing the outgoing probe light pulse to be temporally stretched. At time T5, the outgoing detection light begins to leave the medium. At time T6, the outgoing detection light completely leaves the medium. The optical switch signal of the optical switch (417) is turned on at time T5 and turned off at time T6, precisely aligned with the timing of the outgoing detection light. Only photons within this specific time interval are selected, thereby filtering out a large amount of noise and achieving the purpose of time filtering. At time T7, the readout light (or readout light 2) is turned off. At time T8, a write-read cycle ends, and the next cycle begins.

[0030] [Corrected 02 / 08 / 2024 in accordance with Rule 26] Figure 2 is a timing diagram of the slow-light unit. At time T4, the control light is turned on. Due to the presence of the control light, the electromagnetically induced transparency (EIT) effect occurs, allowing the probe light to propagate through the medium. Due to the slow-light effect, its group velocity in the medium is lower than the speed of light in a vacuum. At time T5, the probe light is turned on. Due to the electromagnetically induced transparency (EIT) effect, the probe light can propagate through the medium. At time T6, the probe light completely leaves the medium. At time T7, the control light is turned off. At time T8, one timing cycle ends, and the next cycle begins.

[0031] The improvement part of the present invention application begins with part 2

[0032] [Corrected 02.08.2024 according to Rule 26] Figure 3 is a schematic diagram of Airy disks of different widths according to the present invention.

[0033] [Corrected 02.08.2024 in accordance with Rule 26] In Figure 3, (a) has a larger width, while (b) has a smaller width. The smaller the Airy disk width, the smaller the minimum resolvable size, and the higher the resolution of the lithography machine. The purpose of this application is to minimize the Airy disk width, thereby improving the resolution of the lithography machine.

[0034] [Corrected 02.08.2024 according to Rule 26] Figure 4 is a schematic diagram showing the Rayleigh criterion limitations of the present invention.

[0035] [Corrected 02 / 08 / 2024 according to Rule 26] In Figure 4, an ideal point light source (1501) emits light (1502) that passes through an aperture (1503) of diameter D, which can be a small hole or a lens system. Due to the diffraction effect, the resulting light spot is an Airy disk (1504). Because of the Airy disk, the minimum resolvable angle θ is calculated using the above formula 1.1.

[0036] [Corrected 02.08.2024 according to Rule 26] Figure 5 is a schematic diagram showing the principle of the minimum resolvable size of a lithography machine according to the present invention.

[0037] [Corrected 02.08.2024 according to Rule 26] In Figure 5, 1601 is the photomask, 1602 is the light-transmitting dot pattern on it, and light (1603) passes through the dot pattern (1602), causing diffraction. The lens system consists of two lenses (1604 and 1605), 1605 is the photolithography objective lens, and light (1603) propagates through the lens system. 1606 is the medium, n is its refractive index, 310 is the wafer, 3102 is the photoresist on the surface of the wafer (310), and θ is the angle of incidence of the objective lens (1605). The minimum resolvable size of the photolithography machine is calculated by the above formula 1.2. After the point light source passes through the photolithography machine lens system, due to the diffraction effect, its light spot is an Airy disk (1607). The smaller the width of the Airy disk, the higher the resolution of the photolithography machine.

[0038] [Corrected 02.08.2024 according to Rule 26] Figure 6 is a schematic diagram of the structure of relevant parts of the lithography machine in an embodiment of the present invention.

[0039] [Corrected 02.08.2024 according to Rule 26] In Figure 6, 301 is a laser, 302 is the output light of the laser (301), 303 is a reflector, 304 is a light processing unit that filters, homogenizes, and adjusts the light beam, 305 is a reflector, 306 is the core functional unit of the present invention, which is an optical storage unit in Example 1 and an optical compression and optical slowing unit in Example 2, 307 is a mask, 308 is a mask positioning table, 309 is a lens group, 310 is a wafer, 311 is a wafer table, 312 is the core functional unit of the present invention, which is an optical storage unit in Example 3 and an optical slowing unit in Example 4. Compared with the existing lithography machine, the main parts improved by the present invention are: laser (301), the core functional units of the present invention (306 and 312). The improvement of the laser (301) mainly lies in the frequency, and the selected frequency is the resonance transition frequency of the medium atoms.

[0040] [Corrected 02.08.2024 according to Rule 26] Figure 7 is a schematic diagram of the principle of the side structure of an enlarged local structure in the lithography machine in an embodiment of the present invention.

[0041] [Corrected 02.08.2024 according to Rule 26] Figure 7(a) shows an enlarged side view of a local structure in a photolithography machine. 309 is a lens group, 310 is a wafer, 311 is a wafer stage, 3102 is the photoresist on the surface of the wafer (310), 312 is the core functional unit of the present invention, which is an optical storage unit in Example 3 and an optical slow light unit in Example 4. 415 is a detection light beam, and 416 is a control light beam.

[0042] [Corrected 02 / 08 / 2024 in accordance with Rule 26] Figure 7(b) shows the structure of 312. 413 is the cryogenic cavity. To maximize the aperture and narrow the Airy disk width, the cryogenic cavity is made of a transparent material (preferably quartz, but other suitable transparent materials are also available) and has the largest possible diameter. The cryogenic cavity also includes a vacuum system and a liquid helium refrigeration system (not shown). The vacuum system provides the required vacuum environment, while the liquid helium refrigeration system lowers the cryogenic cavity temperature to 3.5K and maintains it, keeping the cryogenic cavity temperature as close to absolute zero as possible. This minimizes thermal motion of the medium and reduces noise. 414 is the medium, which can be either a praseodymium-doped yttrium silicate crystal (Pr3+:Y2SiO5) or a europium chloride hexahydrate (EuCl3.6H2O) single crystal.

[0043] [Corrected 02.08.2024 according to Rule 26] Figure 8 is a schematic diagram of the side structure principle of another enlarged local structure in the photolithography machine in an embodiment of the present invention.

[0044] [Corrected 02.08.2024 according to Rule 26] In FIG8, 309 is a lens assembly, 310 is a wafer, 311 is a wafer stage, 3102 is the photoresist on the surface of the wafer (310), 312 is the core functional unit of the present invention, which is an optical storage unit in Example 3 and an optical slow light unit in Example 4, 414 is a medium, which can be atomic vapor of a metal. 415 is a beam of detection light, and 416 is a beam of control light.

[0045] [Corrected 02.08.2024 according to Rule 26] FIG9 is a schematic diagram showing the principle of light beam preparation of an optical storage unit according to Example 3 of the present invention.

[0046] [Corrected 02.08.2024 according to Rule 26] In Figure 9, 401 is the incident light, 402 is the half-wave plate, 403 is the beam splitter, which splits the single beam into two beams, 404 is the detection light focusing lens, which focuses the light (401), 405 is the detection light paralleling lens, which collects the focused light (401) into a parallel beam with a small diameter, 406 is the detection light acousto-optic modulator (AOM), which is responsible for adjusting the frequency of the detection light to the required frequency and is also responsible for turning the light on and off to achieve timing control. 418 is the focusing lens, which focuses the detection light beam (415), 419 is the paralleling lens, which collects the focused detection light beam (415) into a parallel beam with a large diameter, and 415 is the detection light.

[0047] 420 is a beam splitter, which splits one light beam into two light beams. 408 is a control light focusing lens, which focuses the light (401). 409 is a control light parallel lens, which collects the focused light (401) into a parallel light beam with a small diameter. 410 is an acousto-optic modulator (AOM) for control light, which is responsible for adjusting the frequency of the control light to the required frequency and is also responsible for turning the light on and off to achieve timing control. 4161 is the writing light of the control light.

[0048] 429 is a beam splitter, which splits one light beam into two light beams. 430 is a control light focusing lens, which focuses the light (401). 431 is a control light parallel lens, which collects the focused light (401) into a parallel light beam with a small diameter. 432 is an acousto-optic modulator (AOM) for control light, which is responsible for adjusting the frequency of the control light to the required frequency and is also responsible for turning the light on and off to achieve timing control. 4162 is the readout light of the control light.

[0049] 421 is a reflector, 422 is a pump light focusing lens, which focuses the light (401), 423 is a pump light paralleling lens, which collects the focused light (401) into a parallel beam with a small diameter, 424 is an acousto-optic modulator (AOM) for the pump light, which is responsible for adjusting the frequency of the pump light to the required frequency and is also responsible for turning the light on and off to achieve timing control, and 427 is the pump light beam. The components described in this paragraph constitute auxiliary pump light beam splitting, referred to as pump light beam splitting, which functions to pump particles in the ground state energy level to a high energy level during the initial state preparation of electromagnetic induced transparency (EIT). Pump light beam splitting is of an auxiliary nature and may not be used in some application scenarios.

[0050] [Corrected 02.08.2024 according to Rule 26] Figure 10 is a schematic diagram of the principle of light beam preparation of an optical slow light unit in Example 4 of the present invention.

[0051] [Corrected 02.08.2024 according to Rule 26] In Figure 10, 401 is the incident light, 402 is the half-wave plate, 403 is the beam splitter, which splits the single beam into two beams, 404 is the detection light focusing lens, which focuses the light (401), 405 is the detection light paralleling lens, which collects the focused light (401) into a parallel beam with a small diameter, 406 is the detection light acousto-optic modulator (AOM), which is responsible for adjusting the frequency of the detection light to the required frequency and is also responsible for turning the light on and off to achieve timing control. 418 is the focusing lens, which focuses the detection light beam (415), 419 is the paralleling lens, which collects the focused detection light beam (415) into a parallel beam with a large diameter, and 415 is the detection light.

[0052] 420 is a beam splitter, which splits one light beam into two light beams. 408 is a control light focusing lens, which focuses the light (401). 409 is a control light parallel lens, which collects the focused light (401) into a parallel light beam with a small diameter. 410 is an acousto-optic modulator (AOM) for controlling the light, which is responsible for adjusting the frequency of the control light to the required frequency and is also responsible for turning the light on and off to achieve timing control. 416 is the control light.

[0053] 421 is a reflector, 422 is a pump light focusing lens, which focuses the light (401), 423 is a pump light paralleling lens, which collects the focused light (401) into a parallel beam with a small diameter, 424 is an acousto-optic modulator (AOM) for the pump light, which is responsible for adjusting the frequency of the pump light to the required frequency and is also responsible for turning the light on and off to achieve timing control, and 427 is the pump light beam. The components described in this paragraph constitute auxiliary pump light beam splitting, referred to as pump light beam splitting, which functions to pump particles in the ground state energy level to a high energy level during the initial state preparation of electromagnetic induced transparency (EIT). Pump light beam splitting is of an auxiliary nature and may not be used in some application scenarios.

[0054] [Corrected 02.08.2024 according to Rule 26] FIG11 is a schematic diagram showing the principle of achieving the electromagnetic induced transparency (EIT) effect by multiple reflections with a relatively low controlled light intensity in an embodiment of the present invention.

[0055] [Corrected 02.08.2024 according to Rule 26] In Figure 11, 312 is the core functional unit of the present invention, and this figure shows its top plan view. In Example 3, it is an optical storage unit, and in Example 4, it is an optical slow light unit. 413 is a low-temperature cavity. There are quartz light-transmitting windows on two sides of the low-temperature cavity. The low-temperature cavity also includes a vacuum system and a liquid helium refrigeration system, which are not shown in the figure. The vacuum system provides the required vacuum environment, and the liquid helium refrigeration system reduces the temperature of the low-temperature cavity to 3.5K and maintains it, making the temperature of the low-temperature cavity as close to absolute zero as possible, so that the thermal motion of the medium can be reduced and the noise can be reduced. 414 is a medium, and praseodymium-doped yttrium silicate crystal (Pr3+:Y2SiO5) or europium chloride hexahydrate (EuCl3.6H2O) single crystal can be selected. 4161 is a control light beam serving as writing light, 4162 is a control light beam serving as reading light, 427 is a beam serving as auxiliary light, 1803 and 1804 are half-mirrors that merge the two beams into one, 1801 is a high-reflectivity mirror located on the left, and 1802 is a high-reflectivity mirror located on the right.

[0056] [Corrected 02.08.2024 according to Rule 26] Figure 12 shows the probe light transmittance curve and the refractive index curve of the medium when the electromagnetic induced transparency (EIT) effect occurs. This figure is quoted from the reference: "Reducing the speed of light to 17 m / s in an ultracold atomic gas", Nature, Vol. 397, pp. 594–598 (1999).

[0057] [Corrected 02.08.2024 according to Rule 26] In Figure 12, a is the detection light transmittance curve, and b is the refractive index curve.

[0058] End of the Improvement Part 2 of the Present Invention Application DETAILED DESCRIPTION

[0059] Now, in conjunction with the above-mentioned drawings, the specific implementation process of the present invention is described in detail:

[0060] The invention application improves the beginning of part 3

[0061] The medium used in the present invention to achieve the slow light effect, optical storage, or quantum storage functions can be in the form of gas, liquid, or solid. Gaseous media include, but are not limited to, metal atomic vapors such as rubidium (Rb), cesium (Cs), potassium (K), sodium (Na), strontium (Sr), lead (Pb), praseodymium (Pr), and cerium (Ce). When using gases, a transparent gas chamber and a system to maintain a constant temperature are often required. Because gases and liquids flow, which can lead to storage distortion, solids are the preferred storage medium.

[0062] The slow light effect is an important technical feature of the present invention. All currently known methods for achieving slow light can be applied to the present invention, including but not limited to: electromagnetic induced transparency (EIT), coherent population oscillation (CPO), spectral hole burning (SHO), Brillouin scattering (Brillouin scattering), Raman scattering, etc.

[0063] Optical quantum storage is a key technical feature of this embodiment. Currently, solid-state optical storage or quantum storage functions reported in the literature are mostly achieved in rare-earth-doped crystals. Optical storage phenomena in pure rare-earth compound single crystals have also been reported, such as in EuCl3.6H2O (europium chloride hexahydrate) single crystals. Due to lattice distortion caused by impure rare-earth ions, it is generally difficult to directly increase the rare-earth ion concentration to achieve a higher absorption depth. Using pure rare-earth compound crystals offers a solution. Their lattice structure is perfect, free of lattice distortion caused by doping, and they exhibit extremely high optical density. The key to the successful implementation of this invention lies in the perfect distribution of dielectric atoms. A perfect distribution of atoms in a crystal, forming an orderly arrangement of materials, is currently difficult to manufacture on a factory-scale in nanostructures. Ensuring uniform distribution of each atom during doping is also challenging. Therefore, the optical storage medium for photolithography machines is preferably a single or compound crystal, a key feature of this invention to achieve its desired results. Those skilled in the art will understand that, guided by the core spirit of this invention and inspired by its exposition, a wide variety of suitable dielectric materials will continue to be discovered along this path, including but not limited to rare earth element metal crystals, pure rare earth compound crystals, non-rare earth element crystals, and non-rare earth element compound crystals. Any modifications, variations, and alterations within the scope of this patent protection can be successfully implemented, and such modifications, variations, and alterations should fall within the scope of this invention. Another advantage of using pure rare earth compound crystals is their perfect lattice structure, free of lattice distortion caused by doping, effectively reducing scattering noise. In the lithography machine applications of this invention, light source noise can significantly impact lithography results. Therefore, to minimize noise, pure rare earth compound crystals are preferably used, and their chemical purity should be maximized to improve crystal growth process control and reduce lattice distortion. In addition to chemical purity, isotopic purity should also be maximized. Atoms have different isotopes. Publicly available literature indicates that isotopic purification of the chlorine (Cl) element can effectively improve the inhomogeneous broadening (IB) of EuCl₃.6H₂O (europium chloride hexahydrate), resulting in a very narrow linewidth. Isotopic purification of all elements in the compound can further narrow the linewidth, which can improve the efficiency of photon quantum storage. These methods can all be applied in the present invention, and a wide variety of suitable dielectric materials with very narrow IBs will continue to be discovered, achieving optimal implementation results.

[0064] It should be noted that for crystalline media, their lattice structure is highly consistent and often has anisotropic characteristics. The incident direction of the detection light and the control light needs to be precisely adjusted and maintain a certain angle with the lattice structure to achieve good results.

[0065] There are many optical storage solutions, including electromagnetically induced transparency (EIT), the similar spectral hole burning (SHB), off-resonant Raman excitations, photon echoes, and Faraday rotation of light. Within the broad category of photon echoes, there are many sub-categories, including controlled reversible inhomogeneous broadening (CRIB), atomic frequency combs (AFC), gradient echo memory (GEM), and hybrid photon echo (HYPER). The principles of EIT and off-resonant Raman excitations are similar: light is stored in the medium in the form of atomic spin waves. The optical storage of the present invention can adopt all known optical storage technology solutions, including but not limited to the above-mentioned optical storage technology solutions, and is not limited to electromagnetic induced transparency (EIT).

[0066] The frequency of the detection light (415) corresponds to the resonant absorption frequency of the medium of the optical slow light unit or optical storage unit. The frequency is determined by the transition absorption frequency of the energy level selected by the medium (414). If the medium is a praseodymium-doped yttrium silicate crystal (Pr3+:Y2SiO5) and the 3H4→1D2 energy level transition is selected, the wavelength corresponding to the transition frequency is 605.78nm (nanometers). If the medium is a europium chloride hexahydrate (EuCl3.6H2O) single crystal and the 7F0→5D0 energy level transition is selected, the wavelength corresponding to the transition frequency is 579.7033nm.

[0067] [Corrected 02.08.2024 according to Rule 26] Example 3: In this example, an optical storage unit is placed between the objective lens and the wafer. FIG7 shows one type of optical storage unit of this example, and FIG8 shows another type of optical storage unit of this example.

[0068] [Corrected 02.08.2024 according to Rule 26] Figure 1 is a timing diagram of the operation of the optical storage unit. At time T1, the writing light (4161) of the control light (416) is turned on. After a certain period of time, at time T2, the incident detection light (415) is turned on. Due to the presence of the writing light as the control light, an electromagnetically induced transparency (EIT) effect is generated, and the incident detection light can propagate in the medium. Due to the slow light effect, its group velocity in the medium is lower than the speed of light propagating in a vacuum. At time T3, the writing light is turned off. The writing light no longer exists as the control light, and the incident detection light stops propagating in the medium and is stored in the medium. At time T4, the readout light (4162) of the control light (416) turns on. Because the readout light acts as the control light, the incident probe light stored in the medium is restored and converted into the outgoing probe light, which continues to propagate. Due to the slow light effect, its group velocity in the medium is lower than the speed of light propagating in a vacuum. When the readout light is replaced by readout light 2, because the amplitude of readout light 2 is greater than that of the readout light, the restored outgoing probe light is accelerated, thereby achieving compression of the outgoing probe light pulse on the time axis. If the amplitude of readout light 2 is less than that of the readout light, the opposite effect occurs, and the outgoing probe light pulse is stretched on the time axis. At time T5, the outgoing probe light begins to leave the medium. At time T6, the outgoing probe light completely leaves the medium. At time T7, the readout light (or readout light 2) turns off. At time T8, a write-read cycle ends, and the next cycle begins.

[0069] The control light (416) includes a writing light (4161) and a reading light (4162). The frequency, intensity and Airy disk width of the writing light and the reading light can be the same or different. When they are different, they can have a lot of matching options, and any combination of these can be applied in the present invention. When the intensity of the reading light is greater than the intensity of the writing light, the light group speed will increase after the stored light information is released. Conversely, when the intensity of the reading light is less than the intensity of the writing light, the light group speed will slow down after the stored light information is released. The writing light and the reading light can be modulated by optical systems with different apertures, and thus have different Airy disk widths. By using different Airy disk widths, the release process of the stored light information can be fine-tuned and intervened to achieve the best effect. Any combination of the above can be applied in the present invention. By fine-tuning and intervening in the release process of the stored light information, the most suitable parameter combination can be found to achieve the best effect. The present invention has no restrictions on the combination of parameters.

[0070] During exposure, the detection light (415) passes through the lens system and is temporarily stored in the optical storage unit (312) in the form of atomic spin waves. The energy of the light is converted into the energy of the atoms in the optical storage unit medium and then restored to light in the original propagation direction. The light restoration process is to convert the energy of the atoms in the optical storage unit medium into the energy of light. If the frequency and direction of the read light are the same as those of the write light, the stored optical information will be released in the original frequency and direction; if the frequency and direction of the read light are different from those of the write light, the stored optical information will be released in the new frequency and new direction. After the stored light information is released, it can be regarded as an ideal point light source. This point light source propagates in the direction of generation. In this application, it propagates in the original direction before writing. Ideally, since the propagation path has no lens aperture limitation and no other aperture limitation, the aperture is almost infinite. According to the above formula 1.1, the minimum resolvable angle will be infinitesimal. In the actual physical world, infinitesimal does not exist because this leads to infinite energy density. This is a very small unit, much smaller than the resolution target nanometer we need to achieve. We call it the extreme small. The corresponding Airy disk is the extreme small, and the minimum resolvable size will be reduced to the extreme small. When this point light source reaches the wafer, the impact of the Airy disk on the resolution can be ignored, and the resolution of the lithography machine is greatly improved. The above is the most ideal situation. In actual applications, the medium (414) requires support (not shown in the figure) and a low-temperature cavity (413), and the aperture cannot be infinite. The low-temperature cavity is made of a transparent material (preferably quartz material, including other available transparent materials) and has a diameter as large as possible. After the light information stored in the medium (414) is released, it can be regarded as an ideal point light source. This point light source propagates in the direction of generation. The propagation path is not limited by the lens aperture. The propagation path is a transparent quartz material with a diameter as large as possible. The aperture limit becomes smaller, the Airy disk becomes narrower, and the resolution of the lithography machine is improved. As long as the aperture is large enough, the Airy disk will be narrow enough, and the resolution of the lithography machine will be high enough to meet the design requirements. It should be noted that the features described in this paragraph are not only applicable to Example 3, but also to Example 4. The optical storage unit can reduce the minimum resolvable size. The benefit of this is that the aperture requirement for the lithography machine can be reduced. In order to achieve the same resolution requirement, a small aperture can be used, which invisibly reduces the difficulty and cost of manufacturing.

[0071] In the description of this embodiment, the optical storage unit (312) is placed between the objective lens and the wafer. However, since the light propagates in a straight line in the form of a point light source after leaving the optical storage unit, there is no aperture restriction. Therefore, the optical storage unit can be placed at any position between the mask and the wafer. However, considering that the stored light information is released in the original direction, there will be a certain deviation in the direction, which is called the beam direction deviation in the present invention. The smaller the distance between the medium (414) in the optical storage unit (312) and the wafer, the better. This can reduce the exposure position deviation caused by the direction deviation. This is also suitable for Example 4. It will be explained later that, at the microscopic level, Example 4 is essentially also Example 3. When light passes through the fine pattern on the mask, it will be diffracted. Therefore, in this embodiment, the optical storage unit should not be placed in front of the mask on the optical path. The optical storage unit can be close to the mask and the wafer. There are examples of this in practice. For example, the well-known near-field optical microscopy technology is to make the distance between the probe and the object to be detected as small as possible, so as to break through the diffraction limit and achieve nanometer-level resolution.

[0072] [Corrected 02.08.2024 according to Rule 26] Example 4: In this example, a light slow-light unit is placed between the objective lens and the wafer. FIG7 shows one type of light slow-light unit of this example, and FIG8 shows another type of light slow-light unit of this example.

[0073] [Corrected 02.08.2024 according to Rule 26] Figure 2 is a timing diagram of the operation of the optical slow light unit. At time T4, the control light (416) is turned on. Due to the presence of the control light, the electromagnetic induced transparency (EIT) effect is generated, and the detection light (415) can propagate in the medium (414). Due to the slow light effect, its group velocity in the medium is lower than the speed of light propagating in a vacuum. At time T5, the detection light (415) is turned on. Due to the electromagnetic induced transparency (EIT) effect, the detection light can propagate in the medium. At time T6, the detection light completely leaves the medium. At time T7, the control light is turned off. At time T8, one timing cycle ends and the next cycle begins.

[0074] [Corrected 02.08.2024 according to Rule 26] During exposure, after the probe light (415) passes through the lens system, it is in the slow light unit. Because its frequency corresponds to the absorption transition frequency of the medium, when it is incident on the medium (414) alone, the medium strongly resonates and absorbs the frequency, so the probe light cannot pass through the medium. Another beam of control light (416) forms a three-level atomic system with the probe light. When the control light exists, the control light field causes quantum coherent interference, and the probe light is almost not absorbed by the medium, that is, electromagnetic induced transparency (EIT) occurs. The refractive index of the medium changes sharply (see Figure 12 of the specification), thereby causing the group velocity of the probe light to slow down. Here, our focus is on the refractive index of the medium. The frequency of the probe light is selected. At this frequency, the refractive index is at a maximum position. According to formula 1.2, when the refractive index of the medium increases, its minimum resolvable size decreases. When the refractive index increases, the frequency of the light remains unchanged. The group velocity of the light slows down, and the effective wavelength of the light decreases. All of these lead to a narrowing of the Airy disk width.

[0075] In the description of this embodiment, the optical slow light unit is placed between the objective lens and the wafer. However, because the optical slow light unit allows light to exchange energy with the medium, the width of the Airy disk of the light has become narrower. Therefore, the optical slow light unit can be placed at any position between the mask and the wafer. However, due to the deviation of the light beam direction, the distance between the medium (414) in the optical storage unit (312) and the wafer should be as small as possible.

[0076] Light diffracts when passing through fine patterns on a photomask. Therefore, in this embodiment, the optical slow-down unit should not be placed in front of the photomask in the optical path. The optical slow-down unit can be placed in close proximity to the photomask and wafer. This is practically possible, for example, in the well-known near-field optical microscopy technique, which minimizes the distance between the probe and the object being detected, thereby breaking the diffraction limit and achieving nanometer-level resolution.

[0077] It should be noted that other descriptions in this specification or in the following patents:

[0078] Patent 1 (Title: A method for improving the resolution of a photolithography machine; Application number: 2023109064718; Application date: 20230724)

[0079] Patent 2 (Title: Improved Method for Improving the Resolution of a Photolithography Machine; Application Number: 202311159318X; Application Date: 20230910; Patent Number: ZL 2023 1 1159318.X; Authorization Announcement Date: July 2, 2024)

[0080] Unless otherwise specified, the features described in these explanations also apply to Example 3 and Example 4, and these explanations will not be repeated below. The following is a summary of some common features of the above-mentioned Example 3 and Example 4:

[0081] [Corrected 02.08.2024 according to Rule 26] In the above embodiment, in order to make the Airy disk width as narrow as possible and thus achieve better resolution, the measures taken include: 1) referring to FIG7(b), in order to increase the aperture as much as possible, the low-temperature cavity (413) is made of a transparent material (preferably quartz material, including other available transparent materials) and has a diameter as large as possible, and the manufacturing difficulty of its parallel plate structure is lower than that of a lens; 2) the distance between the medium (414) and the wafer (310) is reduced as much as possible; 3) a medium (414) that can be used at room temperature is developed, so that no container is required, including a low-temperature container (413) and a constant temperature heating container (not shown in the figure); 4) the support structure (not shown in the figure) of the medium (414) is made of a transparent material (preferably quartz material, including other available transparent materials) and has a diameter as large as possible, and at the same time, the pressing structure for fixing the medium (414) is designed to be as small as possible to minimize interference with light propagation.

[0082] [Corrected 02.08.2024 according to Rule 26] In the above embodiment, according to existing photolithography technology, the exposure area of ​​the wafer is on the order of 33mm x 26mm. The area of ​​the medium (414) is even larger than this. In such a large area, to achieve the electromagnetic induced transparency (EIT) effect, the required control light (416) intensity is very high. In order to reduce the requirement for the control light intensity, it is preferred to adopt the structure shown in Figure 11, which is called multi-reflected control light to reduce the requirement for the control light intensity. The control light (416) includes writing light (4161) and reading light (4162). High-reflectivity mirrors (1801 and 1802) are used to allow the control light (416) to be reflected multiple times inside the medium (414). The mirrors (1801 and 1802) in the figure can be separate or integrated. The mirror (1801) on the left side of the figure is connected to form a large mirror, and the mirror (1802) on the right side of the figure is connected to form a large mirror.

[0083] In the above embodiments, the core spirit of the present invention is described using a transmissive lens system. The EUV lithography machine uses a reflective projection system, and this type of reflective projection system can also apply the present invention to improve resolution.

[0084] In the above embodiments, the main purpose is to improve the resolution of the lithography machine. The lithography machine is essentially an optical imaging system, so the present invention can be applied to any optical imaging system to narrow the Airy disk width to improve the resolution, including but not limited to microscopes, telescopes, radars, cameras, and other optical imaging systems.

[0085] In the above embodiment, after the exposure light is processed by the optical slow light or optical storage unit, the Airy disk width becomes narrower in the medium and after leaving the medium. In the above embodiment, the feature of the narrowing Airy disk width after passing through the medium is utilized, but in fact, the feature of the narrowing Airy disk width already exists in the medium and can also be utilized.

[0086] In the above-mentioned embodiments, the light slowing down or light storage unit and the feature of narrowing the Airy disk width already exist in the medium and can also be utilized, so the light slowing down or light storage unit can be integrated into the photoresist, so that the photoresist itself is the light slowing down or light storage unit, which can narrow the Airy disk width and thus improve the resolution.

[0087] [Corrected 02.08.2024 according to Rule 26] In the above embodiments, the optical slow-light or optical storage unit, its medium form includes gas, liquid and solid. The optical slow-light or optical storage unit can be in direct contact with the wafer, similar to the immersion lithography technology, where the high-refractive-index liquid is in direct contact with the wafer. In this application environment, it is necessary to add containers for carrying the medium, filtering the medium, circulating the medium, and recovering the medium; when the medium is gas, it is necessary to add auxiliary equipment to make the medium environment reach vacuum. The vacuum environment can be a closed vacuum in a local area of ​​the wafer workbench, or it can be a closed vacuum in the entire lithography machine; in non-vacuum applications, it is necessary to add heating and insulation equipment to keep the medium at a constant temperature. In practical applications, when a container is required, the design of FIG. 7 (b) is followed. The container is made of a transparent material (preferably quartz, including other available transparent materials) and has a diameter as large as possible. The light propagating in the medium (414) includes: a) the originally propagated light; b) or the stored light information after being released, which can be regarded as an ideal point light source, and this point light source propagates in the generated direction. The light propagating in the medium (414) propagates along a path of transparent quartz material with a diameter as large as possible. Without a lens aperture, the aperture limitation is reduced, the Airy disk width is narrowed, and the resolution of the lithography machine is improved. As long as the aperture is large enough, the Airy disk width is narrow enough, and the resolution of the lithography machine is high enough to meet the design requirements. It should be noted that these features in this paragraph apply to all embodiments.

[0088] In the aforementioned embodiments, the direction of the control light in the optical slow light or optical storage unit includes the same direction as the detection light, the opposite direction, the perpendicular direction, and any angle relative to the detection light. An additional consideration for selecting the direction of the control light is that it must not interfere with wafer exposure. When the control light directly impinges on or indirectly reflects onto the exposure area of ​​the wafer, anti-interference measures must be implemented. Method 1 is to select a control light frequency that is outside the photosensitive frequency range of the photoresist.

[0089] In the above embodiment, the measures for reducing optical noise include: 1) in order to prevent the noise of the control light and the noise of the detection light from interfering with the exposure process of the photoresist, a shutter switch of a physical mechanical structure or an electronic structure such as a liquid crystal can be set at the optical path position on the wafer, and the switching time of the shutter switch is precisely coordinated with the switching timing of the control light, and the shutter switch is opened and closed when needed; 2) increasing the absorption depth, and using pure rare earth compound crystals is a solution. Its lattice structure is perfect, there is no lattice distortion caused by doping, and it has an extremely high optical density; 3) increasing the physical thickness of the medium (414); 4) leaving a larger redundancy in the timing control; 5) precisely controlling the intensity of the control light and the detection light.

[0090] In the above embodiment, in order to improve efficiency, the optical storage process can be arranged during the unready time of the workbench. At this time, the workbench is not yet ready for photolithography exposure, but the optical storage step can be performed first. After the workbench is ready, the stored optical information is released for the exposure process.

[0091] In the above-mentioned embodiment, the writing light of the control light, the reading light of the control light, and the detection light can come from the same laser light source or from different laser light sources.

[0092] In the above embodiment, the control light writing light (4161), the control light reading light (4162), and the auxiliary light (427) share a single optical path. This can be changed to a configuration where the control light writing light and the control light reading light share a single optical path, and the auxiliary light separately replicates a similar optical path on the other two sides of the optical slow light or the optical storage unit (312). If the parameters of the control light writing light and the control light reading light are exactly the same, then only one optical path is sufficient.

[0093] In the above embodiment, the directional stability of the controlled light determines the accuracy of the direction in which the stored optical information is released. Assuming that the effective average distance L between the optical slow light or the medium of the optical storage unit and the wafer is 3 cm, to achieve a deviation accuracy Δ of 1 nm, the maximum allowable deviation of the direction angle is

[0094] It can be deduced that the maximum allowable deviation of the direction angle is 3.33x10 -8 To reduce the deviation, the following measures are taken: a) increase the size of the laser resonant cavity that controls the light and the base size of the laser resonant cavity reflector; b) improve the shockproof capability; c) include a laser direction feedback correction device in the optical slow light unit or optical storage unit. According to the above calculation, the direction deviation of the laser at a 10-meter optical path cannot be greater than 3.33x10 -7Meter, that is, 0.333 microns. The function of the feedback correction device is to measure the directional deviation in real time. When a directional deviation occurs, the angle of the reflector of the laser resonator is fine-tuned in real time to keep the directional deviation within the target range. d) Slight changes in temperature can cause deformation of the material. Precise temperature control must be achieved for all relevant components in the laser optical path. e) Light propagates in the medium - after energy exchange between light and the medium, the light energy is converted into the atomic spin wave energy storage of the medium - the atomic spin wave energy storage of the medium is converted into light in the original direction and continues to propagate. The shorter the interval of this energy conversion process, the smaller the impact of the controlled light deviation will be. Therefore, shorter pulse timing and faster frequency switching speed of light closing and opening control are required to achieve this goal. The most ideal effect is that this interval is small enough to be ignored, that is, when switching from the mode of Example 3 to the mode of Example 4, the process of continuous propagation of light in the medium is a continuous process of continuous energy conversion. Therefore, controlling the directional stability of light is equally important for Example 3 and Example 4. In essence, Example 4 is a version of Example 3, except that its light energy conversion process is very fast. The control light with continuous intensity at the macro level has discrete photons. At the micro level, the instantaneous light intensity of its photons at the medium atoms also switches on and off. This is more obvious when the control light intensity is low.

[0095] In the third embodiment described above, if the frequency of the readout light differs from the write light, the stored optical information is released at the new frequency. After the stored optical information is released, it can be considered an ideal point light source, which propagates in the direction it was generated. Since there is no lens system in the propagation path, chromatic aberration is not a concern. Light of different frequencies propagates in the same direction, so the difference in the frequency of the readout light and the write light does not cause chromatic aberration.

[0096] The essential differences between the above-mentioned Examples 3 and 4 and Examples 1 and 2 are: a) in position. The preferred positions of Examples 3 and 4 are between the objective lens and the wafer, while the preferred positions of Examples 1 and 2 are before the photomask; b) in the physical features utilized. Examples 3 and 4 mainly utilize the feature of slowing down light or the medium of the optical storage unit to narrow the Airy disk, while Examples 1 and 2 mainly utilize the feature of slowing down light or the medium of the optical storage unit to slow down light.

[0097] End of the Improvement Part 3 of the present invention application

[0098] While the method and specific embodiments of the invention have been described above with reference to the accompanying drawings and examples, those skilled in the art will appreciate that the invention may be implemented in many different ways. Therefore, it should be understood that the invention is not limited to the preferred embodiments described, but rather encompasses all variations, modifications, and alterations within the scope of the invention, as set forth in the appended claims.

Claims

1. Improvement 4: A method for improving the resolution of a photolithography machine, comprising a light slow light or light storage unit, characterized in that: After the exposure light is processed by the light slowing unit or the light storage unit, the width of the Airy disk becomes narrower in the medium and after leaving the medium.

2. The method according to claim 1, characterized in that The feature "after the exposure light is processed by the optical slow light or the optical storage unit, its Airy disk width becomes narrower in the medium and after leaving the medium" is replaced by the feature "after the exposure light is processed by the optical storage unit, its Airy disk width becomes narrower in the medium and after leaving the medium".

3. The method according to claim 1, characterized in that The feature "after the exposure light is processed by the optical slow-light unit, the Airy disk width becomes narrower in the medium and after leaving the medium" is replaced by the feature "after the exposure light is processed by the optical slow-light or optical storage unit, the Airy disk width becomes narrower in the medium and after leaving the medium".

4. The method according to claim 1, characterized in that The feature "the exposure frequency corresponds to the absorption frequency of the medium of the optical slow-light or optical storage unit, and the Airy disk width of the exposed light becomes narrower in the medium and after leaving the medium after being processed by the optical slow-light or optical storage unit" is replaced by the feature "the exposure frequency corresponds to the absorption frequency of the medium of the optical slow-light or optical storage unit, and the Airy disk width of the exposed light becomes narrower in the medium and after leaving the medium after being processed by the optical slow-light or optical storage unit".

5. The method according to claim 1, characterized in that The feature "the optical storage medium of the optical slow-light or optical storage unit is a monomer or compound crystal, the material is a rare earth element, and the Airy disk width of the exposed light becomes narrower in the medium and after leaving the medium after being processed by the optical slow-light or optical storage unit" is used to replace the feature "the Airy disk width of the exposed light becomes narrower in the medium and after leaving the medium after being processed by the optical slow-light or optical storage unit".

6. The method according to claims 1 to 5, wherein the optical slow light or optical storage unit is characterized by any one of the following features: (a) The light slow light or light storage unit described above controls the direction of the light including the same direction as the detection light, the opposite direction of the detection light, the perpendicular direction to the detection light, and any angle to the detection light. (b) The optical storage schemes selected include Electromagnetically Induced Transparency (EIT), Off-Resonant Raman-type excitations storage or Photo Echo storage.

7. The method according to claims 1 to 5, wherein the optical slow light or optical storage unit is characterized by any one of the following features: (a) Light Slowing Schemes for slowing down the speed of light or optical storage units include electromagnetically induced transparency (EIT), coherent population oscillation (CPO), spectral hole burning, Brillouin scattering or Raman Scattering (b) The exposure frequency corresponds to the resonant absorption frequency of the medium of the optical slow light or optical storage unit. (c) The optical slow light or optical storage unit described above, wherein the medium thereof comprises gas, liquid and solid (c) The optical slow light or optical storage unit can be integrated into the photoresist (d) Multiple reflections of the control light to reduce the requirements for the control light intensity (e) A laser direction feedback correction device is included to monitor and correct the direction deviation of the control light or the detection light in real time. (f) The medium of the optical slow light or optical storage unit is isotopically purified for some or all of its elements to obtain a narrow inhomogeneous broadening.

8. A chip, characterized in that: The chip is prepared by any one of the methods of claims 1 to 7.

9. An optical imaging system, characterized in that: The optical imaging system is prepared by any one of the methods of claims 1 to 7.

10. The optical imaging system according to claim 9, wherein the optical imaging system comprises a microscope, a telescope, a radar, a camera and a video camera.

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