CN114995068A

CN114995068A - Exposure light frequency enhancing device, photomask and preparation method thereof

Info

Publication number: CN114995068A
Application number: CN202210649237.7A
Authority: CN
Inventors: 季明华; 黄早红; 任新平; 林岳明
Original assignee: Shanghai Chuanxin Semiconductor Co ltd
Current assignee: Shanghai Chuanxin Semiconductor Co ltd
Priority date: 2022-06-09
Filing date: 2022-06-09
Publication date: 2022-09-02

Abstract

The invention provides an exposure light frequency enhancing device, a photomask and a preparation method thereof, wherein the device comprises a light-transmitting substrate and a surface plasma excimer layer, the surface plasma excimer layer comprises a plurality of nano unit structures, the nano unit structures are respectively arranged in a first direction and a second direction of the surface plasma excimer layer plane to be periodically arranged at intervals which can be matched with the wavelength of the exposure light to generate a sum frequency effect, the sum frequency effect can form sum frequency light which penetrates through the light-transmitting substrate, and the proportion of the power of the sum frequency light to the total power of the exposure light which penetrates through the surface plasma excimer layer is less than or equal to 30%. The exposure light contains higher-frequency sum-frequency light within 30%, the resolution and the contrast of the projection type photoetching process can be improved, and a large amount of used light sources with original frequency are light sources, so that photoetching components are basically not required to be adjusted, and the energy loss is less.

Description

Exposure light frequency enhancing device, photomask and preparation method thereof

Technical Field

The invention belongs to the field of semiconductor manufacturing, and particularly relates to an exposure light frequency enhancing device for projection lithography, a photomask and a preparation method thereof.

Background

The photolithography technology has been continuously developed along with the manufacturing method of the integrated circuit, the line width has been continuously reduced, the area of the semiconductor device has become smaller and smaller, and the layout of the semiconductor has evolved from the common single function separation device to the integration of the high-density multifunctional integrated circuit; from the first IC (integrated circuit) to the next LSI (large scale integrated circuit), VLSI (very large scale integrated circuit), to today's ULSI (ultra large scale integrated circuit), the area of the device is further reduced. Considering the restrictions of adverse factors such as complexity of process development, long-term performance, high cost and the like, how to further improve the integration density of devices on the basis of the prior art level to obtain as many effective chips as possible on the same silicon chip, thereby improving the overall benefits will be more and more emphasized by chip manufacturers. The projection lithography process plays a key role, and for the lithography technology in this document, the projection lithography apparatus, the process and the mask technology are among the important aspects.

The simplest binary photomask (BIM) or phase shift Photomask (PSM) has a mask layer Cr with a thickness of about 50-100 nm. The phase shift of the phase shift photomask may be provided by the trench depth on the quartz substrate after patterning.

The bi-layer phase shift photomask may include a light-shielding Cr layer and a MoSiON layer having a MoSiON layer thickness of about 50-150nm to ensure its phase shift and attenuation functions. After patterning of the bilayer phase shift photomask is completed, the amount of phase shift and the amount of attenuation of the bilayer phase shift photomask are determined by the thickness of the MoSiON layer. The phase shift photomask may also include a multi-layer structure to achieve better photomask performance.

However, the above photomask still has problems of insufficient resolution and contrast of the pattern on the silicon wafer.

It should be noted that the above background description is only for the convenience of clear and complete description of the technical solutions of the present application and for the understanding of those skilled in the art. Such solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the present application.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention is directed to an exposure light frequency enhancing device, a photomask and a method for manufacturing the same, which are used to solve the problems of insufficient resolution and contrast of the photomask in the prior art of projection type.

To achieve the above and other related objects, the present invention provides an exposure light frequency enhancing apparatus for projection lithography, the frequency enhancing apparatus comprising: a light-transmitting substrate comprising opposing first and second faces; the surface plasmon layer is positioned on the first surface of the light-transmitting substrate and comprises a plurality of nano unit structures, the nano unit structures are arranged in the first direction and the second direction of the surface plasmon layer plane at intervals which are periodically matched with the wavelength of the exposure light to generate a sum frequency effect, the sum frequency effect can form sum frequency light penetrating through the light-transmitting substrate, and the proportion of the power of the sum frequency light to the total power of the exposure light penetrating through the surface plasmon layer is less than or equal to 30%.

Optionally, the exposure light comprises two beams of polarized light polarized parallel to the row direction and polarized parallel to the column direction.

Optionally, the periodic sizes of the nano unit structures arranged in the first direction and the second direction are respectively integer multiples of 1 to 5 of the wavelength of the exposure light.

Optionally, the surface plasmon layer may generate surface plasmons under the action of the exposure light, a portion of the surface plasmons pass through the surface plasmon layer to enhance the field intensity of the near-field light, and another portion of the near-field of the surface plasmons may be resonantly matched with a first optical wave polarized in parallel to the first direction of the surface and a second optical wave polarized in the second direction based on the periodic interval arrangement to generate a sum frequency effect to form a third optical wave perpendicular to the surface plasmon layer, where the third optical wave is the sum frequency light.

Optionally, the resonant frequencies of the surface plasmon near-field optical wave in the first direction and the second direction are respectively the same as or integer times the optical frequencies of the first optical wave and the second optical wave polarized in the same direction.

Optionally, the periodic size of the nano unit structures arranged in the first direction is an integral multiple of 1 to 5 of the wavelength of the exposure light, so that the resonant frequency in the first direction is 1 to 0.2 times of the first light wavelength, the periodic size of the nano unit structures arranged in the second direction is an integral multiple of 1 to 5 of the wavelength of the exposure light, and the resonant frequency in the second direction is 1 to 0.2 times of the second light wavelength.

Optionally, the resonant frequency f1 and the wavelength λ 1 of the first direction, the resonant frequency f2 and the wavelength λ 2 of the second direction, the frequency f3 and the wavelength λ 3 of the third optical wave satisfy the following formula: f3 ═ f1+ f2, λ 3 ═ λ 1 × λ 2/(λ 1+ λ 2).

Optionally, the thickness of the surface plasmon layer is between one half and three times the wavelength of the exposure light.

Optionally, the first direction and the second direction are perpendicular.

Optionally, the material of the surface plasmon layer comprises a semi-transparent metal or a uv transparent conductive oxide.

Optionally, the material of the surface plasmon layer has a direct transmittance of exposure light of greater than or equal to 40%.

Optionally, the material of the surface plasmon layer comprises a semitransparent metal, the semitransparent metal comprises one of Al, Au, Ag and Pd, and the semitransparent metal has a thickness less than or equal to 20 nm.

Optionally, the material of the surface plasmon layer comprises a transparent conductive oxide to ultraviolet light, the transparent conductive oxide comprises one of indium oxide, tin oxide, indium tin oxide, and zinc oxide, and the thickness of the transparent conductive oxide is less than or equal to 30 nanometers.

Optionally, the translucent conductive object has a direct transmittance of 50% or more to the exposure light, and the transparent conductive object has a direct transmittance of 80% or more to the exposure light.

Optionally, the sum frequency light has a power of 10% to 20% of the total power of the exposure light passing through the surface plasmon layer.

Optionally, the wavelength of the third light wave is 15% to 25% smaller than the wavelength of the exposure light.

Optionally, the size of the nano unit structure is equal to the interval between two adjacent nano unit structures.

Optionally, the shape of the nano-cell structure comprises one of a square, a rectangle, a circle, and an ellipse.

The invention also provides a method for preparing the exposure light frequency enhancing device for projection lithography, which comprises the following steps: providing a light-transmitting substrate; and forming a surface plasma excimer layer on the light-transmitting substrate.

The present invention also provides a photomask for projection lithography, the photomask comprising: an exposure light frequency enhancing apparatus for projection lithography according to any one of the above aspects; a transparent substrate having opposing first and second faces, the second face bonded to the second face of the light-transmissive substrate of the enhancement device; and the shading layer covers the first surface of the transparent substrate, and an exposure window penetrating through the shading layer is arranged in the shading layer.

Optionally, the photomask further includes a phase shift material layer, the phase shift material layer is located between the transparent substrate and the light shielding layer, and the exposure window stops at a top surface of the phase shift material layer.

Optionally, the material of the transparent substrate includes synthetic quartz glass, the material of the light shielding layer includes one of chromium, chromium oxide and chromium nitride, and the material of the phase shift material layer includes one of molybdenum silicon oxide, molybdenum silicon oxynitride, molybdenum silicon oxycarbide, chromium silicon oxide, chromium silicon oxynitride and chromium silicon oxycarbide.

The present invention also provides a method of manufacturing a photomask for projection lithography according to any one of the above aspects, the method comprising the steps of: providing a light-transmitting substrate, wherein the light-transmitting substrate is provided with a first surface and a second surface which are opposite; forming a surface plasma excimer layer on the first surface of the light-transmitting substrate; providing a transparent substrate, wherein the transparent substrate is provided with a first surface and a second surface which are opposite, a shading layer is formed on the first surface of the transparent substrate, and an exposure window is formed in the shading layer; and bonding the second surface of the light-transmitting substrate and the second surface of the transparent substrate.

The present invention also provides a photomask for projection lithography, the photomask comprising: an exposure light frequency enhancing apparatus for projection lithography according to any one of the above aspects; and the shading layer covers the second surface of the light-transmitting substrate, and an exposure window penetrating through the shading layer is arranged in the shading layer.

Optionally, the photomask further includes a phase shift material layer, the phase shift material layer is located between the light-transmitting substrate and the light-shielding layer, and the exposure window stops at a top surface of the phase shift material layer.

Optionally, the material of the light-shielding layer includes one of chromium, chromium oxide and chromium nitride, and the material of the phase-shift material layer includes one of molybdenum silicon oxide, molybdenum silicon oxynitride, molybdenum silicon carbide oxynitride, chromium silicon oxide, chromium silicon oxynitride and chromium silicon carbide oxynitride.

The present invention also provides a method of manufacturing a photomask for projection lithography according to any one of the above aspects, the method comprising the steps of: providing a light-transmitting substrate, wherein the light-transmitting substrate is provided with a first surface and a second surface which are opposite; forming a surface plasma excimer layer on the first surface of the light-transmitting substrate; and forming a light shielding layer on the second surface of the light-transmitting substrate, and forming an exposure window in the light shielding layer.

As described above, the exposure light frequency enhancing apparatus, the photomask and the method for manufacturing the same according to the present invention have the following advantageous effects:

the invention provides an exposure light frequency enhancing device, which is characterized in that a surface plasma laser element layer is arranged on the surface of a light-transmitting substrate, the surface plasma laser element layer comprises a plurality of nano unit structures, the material of the surface plasma laser element layer comprises a semitransparent conductive object or a conductive object transparent to ultraviolet rays, the surface plasma excimer layer comprises a plurality of nano unit structures, the nano unit structures are respectively arranged in a first direction and a second direction of the plane of the surface plasma laser element layer and can be matched with the wavelength of exposure light ((such as 365nm i-line light, 248nm ultraviolet UV, 193nm deep ultraviolet DUV and the like) to generate periodic interval arrangement of sum frequency effect, the sum frequency effect can form sum frequency light penetrating through the light-transmitting substrate, the ratio of the power of the sum frequency light to the total power of the exposure light penetrating through the surface plasma laser element layer is less than or equal to 30%, the scheme is based on the sum frequency effect, if the resonant frequencies of the surface plasmon near-field optical waves in the first direction and the second direction are respectively the same as or integral fractional times of the optical frequencies of the first optical wave and the second optical wave polarized in the same direction, a third optical wave (sum frequency light) which has a sum frequency effect and is perpendicular to the surface can be formed, the frequency of the third optical wave is the sum of the resonant frequencies in the first direction and the second direction, and the wavelength of the third optical wave is smaller than the wavelength of the first optical wave and smaller than the wavelength of the second optical wave, so that the exposure light after passing through the surface plasmon layer has a first part with the unchanged wavelength and a second part with the shortened wavelength, thereby greatly improving the resolution and the contrast of the lithography process. Meanwhile, under the scheme, a large number of light sources with the original frequency are used, photoetching assemblies with the wavelengths of the original light sources can be basically not used or less adjusted, high light transmittance is guaranteed, and energy loss is less.

The surface plasma excimer layer is a semitransparent or transparent conductive object, so that surface plasmons can be generated to enhance exposure light on one hand, and shielding of the exposure light can be effectively reduced, transmittance of the exposure light is improved, and final light intensity of a photoetching process is guaranteed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the application, are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is to be understood that the drawings in the following description are of some embodiments of the application only.

Fig. 1 to 4 are schematic diagrams showing structures of steps of a method for manufacturing an exposure light frequency enhancing device according to embodiment 1 of the present invention, in which fig. 3 is a schematic diagram showing a cross-sectional structure of the exposure light frequency enhancing device according to embodiment 1 of the present invention, and fig. 4 is a schematic diagram showing a top view structure of the exposure light frequency enhancing device according to embodiment 1 of the present invention.

Fig. 5 to 9 are schematic views showing structures of steps of the method for manufacturing a photomask according to embodiment 2 of the present invention, wherein fig. 8 and 9 are schematic views showing structures of two photomasks according to embodiment 2 of the present invention, respectively.

Fig. 10 and 11 are schematic structural views of two photomasks according to embodiment 3 of the invention.

Description of the element reference numerals

101 light-transmitting substrate

102 surface plasmon layer

201 transparent substrate

202 light-shielding layer

203 layer of phase shift material

Detailed Description

The following embodiments of the present invention are provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

Example 1

As shown in fig. 3 and 4, the present embodiment provides an exposure light frequency enhancing apparatus for projection lithography, the enhancing apparatus comprising: a light-transmitting substrate 101 including opposing first and second faces; the surface plasmon layer 102 is located on the first surface of the light-transmitting substrate 101, the surface plasmon layer 102 includes a plurality of nano-unit structures, the plurality of nano-unit structures are respectively arranged in the row direction and the column direction to be arranged at periodic intervals capable of cooperatively generating a sum frequency effect, the surface plasmon layer 102 is used for generating surface plasmon polaritons under the action of exposure light, part of the surface plasmon polaritons penetrate through the surface plasmon layer 102 to enhance the field strength of the near-field light, and the near field of the other part of the surface plasmon polaritons can be matched with a first light wave polarized in the first direction parallel to the surface and a second light wave polarized in the second direction based on the periodic interval arrangement to generate a third light wave perpendicular to the surface plasmon polaritons through the sum frequency effect; the exposure light includes two beams of polarized light polarized parallel to the row direction and polarized parallel to the column direction. The wavelength of the third light wave can be designed to be smaller than the wavelength of the first light wave and smaller than the wavelength of the second light wave. The invention provides an exposure light frequency enhancing device, which is characterized in that a surface plasmon layer is arranged on the surface of a light-transmitting substrate and comprises a plurality of nano unit structures which are periodically arranged at intervals in the row direction and are periodically arranged at intervals in the column direction, the surface plasmon layer can generate surface plasmon polaritons under the action of exposure light (the wavelength of the exposure light can be 365nm, 248nm, 193nm and the like), part of the surface plasmon polaritons can enhance the field intensity of the exposure light after penetrating through the surface plasmon polariton layer, the other part of the surface plasmon polariton is polarized into a first light wave in the first direction and a second light wave in the second direction, the first light wave and the second light wave form a third light wave through the sum frequency effect after penetrating through the surface plasmon polariton layer, the wavelength of the third light wave is smaller than the wavelength of the first light wave and smaller than the wavelength of the second light wave, and the exposure light has a first part with unchanged wavelength and a wavelength after penetrating through the surface plasmon polariton layer The second portion is shortened, thereby greatly improving the resolution and contrast of the lithographic process.

In one embodiment, the resonant frequencies of the surface plasmon near-field optical waves in the first direction and the second direction are respectively the same as or integer times the optical frequencies of the first optical wave and the second optical wave polarized in the same direction.

In one embodiment, the light transmittance of the light-transmitting substrate 101 is greater than 80%, and the light-transmitting substrate 101 may include synthetic quartz glass, soda glass, or the like, but is preferably synthetic quartz glass. The thickness of the transparent substrate 101 may be a conventional thickness or thinner, and by way of example, the thickness of the transparent substrate 101 may be between 2 mm and 8 mm, for example, the thickness of the transparent substrate 101 may be 6 mm.

In one embodiment, the exposure light includes, for example, 365nm i-line light, 248nm UV light, 193nm DUV light, and the like.

In one embodiment, surface plasmons are generated when exposure light is irradiated to the surface plasmon layer 102, and the surface plasmons of the present embodiment, which are surface wave modes of an electromagnetic field propagating at an interface between a conductor (e.g., a metal) and a medium, are formed by bulk oscillation of a high-density free electron gas in the conductor under excitation of the electromagnetic field of the exposure light, and have a high degree of near-field enhancement effect and super-diffraction-limited optical field locality, so that the field intensity of the exposure light on the surface of the mask substrate can be effectively enhanced.

In one embodiment, the material of the surface plasmon layer 102 has a direct transmittance of exposure light of greater than or equal to 40%. To minimize the shielding of the exposure light by the surface plasmon layer 102.

In one embodiment, the surface plasmon layer 102 comprises a semi-transparent conductor or a transparent conductor. To minimize the shielding of the exposure light by the surface plasmon layer 102.

In one embodiment, the translucent conductive material has a transmittance of 50% or more to the exposure light, and the transparent conductive material has a transmittance of 80% or more to the exposure light.

In one embodiment, the material of the surface plasmon layer 102 comprises a translucent metal comprising one of Al, Au, Ag, and Pd, and the thickness h of the translucent metal is less than or equal to 20 nanometers. In this embodiment, the material of the surface plasmon layer 102 is gold (Au), and the thickness of the gold is 15 nm. The metal can have a certain light transmittance and is semitransparent by adjusting the thickness of the metal, and meanwhile, the metal needs to have a certain thickness to ensure the amount of the excited surface plasmon, and in a preferred embodiment, the thickness h of the semitransparent metal is preferably 10 nanometers to 20 nanometers.

In one embodiment, the material of the surface plasmon layer 102 comprises a transparent conductive oxide comprising one of indium oxide, tin oxide, indium tin oxide, and zinc oxide, and the thickness of the transparent conductive oxide is less than or equal to 30 nanometers. When the surface plasmon layer 102 is a transparent conductive oxide, the surface plasmon layer 102 can be set to a large thickness so as to increase the amount of the excited surface plasmons, and at the same time, the transparent conductive oxide increases in thickness without significantly decreasing the transmittance of the exposure light, and preferably, the surface plasmon layer 102 can have a thickness of 20 nm to 30 nm.

In this embodiment, the first direction is perpendicular to the second direction. The resonance frequency of the surface plasmon layer in the first direction is positively correlated with the wavelength of the first light wave and the structural period size of the nano-unit structures arranged in the first direction, and the resonance frequency of the surface plasmon layer in the second direction is positively correlated with the wavelength of the second light wave and the structural period size of the nano-unit structures arranged in the second direction. The periodic size of the nano unit structures arranged in the first direction and the periodic size of the nano unit structures arranged in the second direction are controlled through design, so that the resonant frequency of plasmons in the first direction and the second direction is equal to or integer times of the frequency of the first light wave and the second light wave, a sum frequency effect is formed, and a third light wave perpendicular to the surface is generated, wherein the frequency of the third light wave is the sum of the resonant frequencies in the first direction and the second direction.

In one embodiment, the resonant frequency f1 and wavelength λ 1 of the first direction, the resonant frequency f2 and wavelength λ 2 of the second direction, the frequency f3 and wavelength λ 3 of the third optical wave satisfy the following formula: f3 ═ f1+ f2, λ 3 ═ λ 1 × λ 2/(λ 1+ λ 2).

In one embodiment, the nano-unit structures arranged in the first direction have a period size of one to five times the wavelength of the exposure light, such that the resonance frequency in the first direction is 1 to 0.2 times the wavelength of the first light, the nano-unit structures arranged in the second direction have a period size of one to five times the wavelength of the exposure light, and the resonance frequency in the second direction is 1 to 0.2 times the wavelength of the second light.

For example, when the exposure light is the same light, and the period size of the nano unit structures arranged in the first direction is equal to the wavelength of the exposure light, and the period size of the nano unit structures arranged in the second direction is equal to the wavelength of the exposure light, the frequency of the first light wave and the second light wave is f, the wavelength is λ, the frequency of the third light wave is 2f, and the wavelength is λ/2. However, for exposure light with a shorter wavelength λ (such as 193nm DUV), the period size of the nano-unit structures arranged in the first direction may be equal to the wavelength of the exposure light, the wavelength of the polarized first light wave is equal to the wavelength of the exposure light, both λ and λ, and the period size of the nano-unit structures arranged in the second direction is three times the wavelength of the exposure light, so that the polarized second wavelength may be increased to 3 λ, and the wavelength of the third light wave is 3/4 λ, so that on one hand, the wavelength of the third light wave may be shortened, and the wavelength of the third light wave may not be too short to be easily absorbed by the transparent substrate 101, thereby ensuring that the third light wave has a certain intensity. With the above arrangement rule, it is preferable that the wavelength of the third light wave is set to be 15% to 25% smaller than the wavelength of the exposure light.

Since the third light wave has a shorter wavelength and is weaker than the original wavelength of the exposure light, it is preferable to ensure a certain amount of the original wavelength of the exposure light and a part of the third light wave with a shorter wavelength during the photolithography exposure to ensure the exposure intensity and simultaneously improve the resolution and contrast of the photolithography process, and based on this, in one embodiment, the power of the third light wave accounts for less than or equal to 20% of the total power of the exposure light passing through the surface plasmon layer 102. For example, the power of the third light wave is preferably 10% to 20% of the total power of the exposure light passing through the surface plasmon layer 102.

In one embodiment, the size of the nano-unit structure and the interval between two adjacent nano-unit structures are equal.

In one embodiment, the shape of the nano-cell structure comprises one of a square, a rectangle, a circle, and an ellipse.

The invention provides an exposure light frequency enhancement device, which is characterized in that a surface plasmon layer is arranged on the surface of a light-transmitting substrate and comprises a plurality of nano unit structures which are periodically arranged at intervals in the row direction and are periodically arranged at intervals in the column direction, the surface plasmon layer can generate surface plasmon polaritons under the action of exposure light (the wavelength of the exposure light can be 365nm, 248nm, 193nm and the like), part of the surface plasmon polaritons can enhance the field intensity of the exposure light after penetrating through the surface plasmon polaritons layer, the other part of the surface plasmon polaritons is polarized into a first light wave in the first direction and a second light wave in the second direction, the first light wave and the second light wave form a third light wave after penetrating through the surface plasmon polaritons layer through the sum frequency effect, and the wavelength of the third light wave is smaller than that of the first light wave and smaller than that of the second light wave, so that the exposure light after penetrating through the surface plasmon polaritons layer has a first part and a constant wavelength The second portion is shortened, thereby greatly improving the resolution and contrast of the lithographic process.

As shown in fig. 1 to 4, this embodiment further provides a method for preparing an exposure light frequency enhancing device for projection lithography according to any one of the above aspects, including the steps of: 1) providing a transparent substrate 101, as shown in fig. 1; 2) a surface plasmon layer 102 is formed on the transparent substrate 101 through a sputtering process and a photolithography-etching process, as shown in fig. 2 and 3.

Example 2

As shown in fig. 8 and 9, the present embodiment provides a photomask for projection lithography, the photomask comprising:

the structure of the exposure light frequency enhancing device used for projection lithography is as described in embodiment 1, and is not described herein.

The transparent substrate 201 has opposite first and second faces, the second face being bonded to the second face of the light-transmissive substrate 101 of the enhancement device.

The light-shielding layer 202 covers the first surface of the transparent substrate 201, and an exposure window penetrating through the light-shielding layer 202 is formed in the light-shielding layer 202.

In one embodiment, the material of the transparent substrate 201 includes synthetic quartz glass, and the material of the light-shielding layer 202 includes one of chromium, chromium oxide, and chromium nitride.

In one embodiment, as shown in FIG. 9, the photomask further comprises a phase shift material layer 203, the phase shift material layer 203 is located between the transparent substrate 201 and the light-shielding layer 202, and the exposure window stops at the top surface of the phase shift material layer 203. The phase shift material layer 203 is made of one of molybdenum silicon oxide, molybdenum silicon oxynitride, molybdenum silicon oxycarbide, chromium silicon oxide, chromium silicon oxynitride, and chromium silicon oxycarbide.

As shown in fig. 1 to 9, the present embodiment also provides a method for manufacturing a photomask for projection lithography, the method comprising the steps of: 1) providing a light-transmitting substrate 101, wherein the light-transmitting substrate 101 has a first side and a second side opposite to each other, as shown in fig. 1; 2) forming a surface plasmon layer 102 on the first surface of the light-transmitting substrate 101 through a sputtering process and a photolithography-etching process, as shown in fig. 2 and 3; 3) providing a transparent substrate 201, wherein the transparent substrate 201 has a first surface and a second surface opposite to each other, forming a light-shielding layer 202 on the first surface of the transparent substrate 201, and forming an exposure window in the light-shielding layer 202, as shown in fig. 5 to 7; 4) the second face of the transparent substrate 101 and the second face of the transparent substrate 201 are bonded as shown in fig. 8.

In the embodiment, the photomask integrated with the exposure light frequency enhancing device and used for projection lithography is formed in a bonding mode, and the surface plasmon layer 102 and the light shielding layer 202 can be respectively prepared on different substrates, so that the surface plasmon layer 102 and the light shielding layer 202 are not affected with each other, and finally, only two substrates need to be bonded through a bonding process, and the stability and yield of photomask manufacturing can be effectively ensured.

Example 3

As shown in fig. 10 and 11, the present embodiment provides a photomask for projection lithography, including: an exposure light frequency enhancing device for projection lithography, the structure of which is as described in embodiment 1 and is not described herein, and a light shielding layer 202.

The light-shielding layer 202 covers the second surface of the light-transmitting substrate 101, and an exposure window penetrating through the light-shielding layer 202 is formed in the light-shielding layer 202. The material of the light-shielding layer 202 includes one of chromium, chromium oxide, and chromium nitride.

In one embodiment, as shown in FIG. 11, the photomask further comprises a phase shift material layer 203, the phase shift material layer 203 is located between the transparent substrate 101 and the light-shielding layer 202, and the exposure window stops at the top surface of the phase shift material layer 203. The phase shift material layer 203 is made of one of molybdenum silicon oxide, molybdenum silicon oxynitride, molybdenum silicon oxycarbide, chromium silicon oxide, chromium silicon oxynitride, and chromium silicon oxycarbide.

As shown in fig. 1 to 3, fig. 10 and fig. 11, the present embodiment further provides a method for manufacturing a photomask for projection lithography, including the steps of: 1) providing a light-transmitting substrate 101, wherein the light-transmitting substrate 101 has a first side and a second side opposite to each other, as shown in fig. 1; 2) forming a surface plasmon layer 102 on the first surface of the light-transmitting substrate 101 through a sputtering process and a photolithography-etching process, as shown in fig. 2 and 3; 3) a light-shielding layer 202 is formed on the second surface of the transparent substrate 101, and an exposure window is formed in the light-shielding layer 202, as shown in fig. 10.

The surface plasmon layer 102 and the light shielding layer 202 of the embodiment are prepared on the same substrate, one substrate can be saved, and one bonding process can be saved, so that the cost of the preparation process can be effectively reduced, and compared with the bonding of two substrates, the whole thickness of the photomask can be effectively reduced by adopting the same substrate, and the transmittance of exposure light is improved.

the exposure light frequency enhancing device provided by the invention is characterized in that a surface plasmon layer is arranged on the surface of a light-transmitting substrate and comprises a plurality of nano unit structures which are periodically arranged at intervals in the row direction and are periodically arranged at intervals in the column direction, the surface plasmon layer can generate surface plasmons under the action of exposure light (the wavelength of the exposure light can be 365nm, 248nm, 193nm and the like), part of the surface plasmons can enhance the field intensity of the exposure light after penetrating through the surface plasmon layer, the near field of the other part of the surface plasmons can interact with a first light wave polarized in a first direction and a second light wave polarized in a second direction which are parallel to the surface, if the resonant frequencies of the near field light waves of the surface plasmons in the first direction and the second direction are the same as or are integer multiples of the light frequencies of the first light wave and the second light wave polarized in the same direction respectively, a third light wave with a sum frequency effect and perpendicular to the surface is formed, the frequency of the third light wave is the sum of the resonant frequencies in the first direction and the second direction, and the wavelength of the third light wave is smaller than that of the first light wave and smaller than that of the second light wave, so that the exposure light after passing through the surface plasmon layer has a first part with unchanged wavelength and a second part with shortened wavelength, thereby greatly improving the resolution and contrast of the photolithography process.

Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. An exposure light frequency enhancing apparatus for projection lithography, the frequency enhancing apparatus comprising:

a light-transmitting substrate including opposing first and second faces;

the surface plasmon layer is positioned on the first surface of the light-transmitting substrate and comprises a plurality of nano unit structures, the nano unit structures are respectively arranged in the first direction and the second direction of the surface plasmon polariton layer plane at periodic intervals which can be matched with the wavelength of the exposure light to generate a sum frequency effect, the sum frequency effect can form sum frequency light which penetrates through the light-transmitting substrate, and the proportion of the power of the sum frequency light in the total power of the exposure light which penetrates through the surface plasmon polariton layer is less than or equal to 30%.

2. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the exposure light includes two polarized lights polarized parallel to the first direction and polarized parallel to the second direction.

3. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the periodic sizes of the nano unit structures arranged in the first direction and the second direction are respectively integral multiples of 1-5 of the wavelength of the exposure light.

4. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the surface plasmon layer can generate surface plasmon under the action of the exposure light, one part of the surface plasmon penetrates through the surface plasmon layer to enhance the field intensity of near-field light, the other part of the near field of the surface plasmon can be in resonance matching with a first light wave polarized in a first direction parallel to the surface and a second light wave polarized in a second direction based on the periodic interval arrangement to generate a sum frequency effect to form a third light wave perpendicular to the surface plasmon layer, and the third light wave is the sum frequency light.

5. The exposure light frequency enhancing apparatus for projection lithography according to claim 4, wherein: the resonant frequencies of the surface plasmon near-field optical wave in the first direction and the second direction are respectively the same as or integral-fraction times of the optical frequencies of the first optical wave and the second optical wave polarized in the same direction.

6. The exposure light frequency enhancing apparatus for projection lithography according to claim 4, wherein: the periodic size of the nano unit structures distributed in the first direction is an integral multiple of 1 to 5 times of the wavelength of the exposure light, so that the resonant frequency in the first direction is 1 to 0.2 times of the wavelength of the first light, the periodic size of the nano unit structures distributed in the second direction is an integral multiple of 1 to 5 times of the wavelength of the exposure light, and the resonant frequency in the second direction is 1 to 0.2 times of the wavelength of the second light.

7. The exposure light frequency enhancing apparatus for projection lithography according to claim 4, wherein: the resonant frequency f1 and the wavelength λ 1 of the first direction, the resonant frequency f2 and the wavelength λ 2 of the second direction, and the frequency f3 and the wavelength λ 3 of the third light satisfy the following formula: f3 ═ f1+ f2, λ 3 ═ λ 1 × λ 2/(λ 1+ λ 2).

8. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the thickness of the surface plasma laser element layer is between one half and three times of the wavelength of the exposure light.

9. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the first direction and the second direction are perpendicular.

10. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the power of the sum frequency light accounts for 10% -20% of the total power of the exposure light passing through the surface plasma excimer layer.

11. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the direct transmittance of the material of the surface plasma excimer layer to exposure light is greater than or equal to 40%.

12. The exposure light frequency enhancing apparatus for projection lithography according to claim 1, wherein: the material of the surface plasmon layer comprises a semitransparent metal or a transparent conductive oxide for ultraviolet rays.

13. The exposure light frequency enhancing apparatus for projection lithography according to claim 12, wherein: the semitransparent metal comprises one of Al, Au, Ag and Pd, and the thickness of the semitransparent metal is less than or equal to 20 nanometers; the transparent conductive oxide includes one of indium oxide, tin oxide, indium tin oxide, and zinc oxide, and a thickness of the transparent conductive oxide is less than or equal to 30 nanometers.

14. The exposure light frequency enhancement device for projection lithography according to claim 12, wherein: the translucent conductive object has a direct transmittance of 50% or more to the exposure light, and the transparent conductive object has a direct transmittance of 80% or more to the exposure light.

15. A method of manufacturing an exposure light frequency enhancing device for projection lithography according to any one of claims 1 to 14, comprising the steps of:

providing a light-transmitting substrate;

and forming a surface plasma excimer layer on the light-transmitting substrate.

16. A photomask for projection lithography, said photomask comprising:

the exposure light frequency enhancing apparatus for projection lithography according to any one of claims 1 to 14;

a transparent substrate having opposing first and second faces, the second face bonded to the second face of the light-transmissive substrate of the enhancement device;

and the shading layer covers the first surface of the transparent substrate, and an exposure window penetrating through the shading layer is arranged in the shading layer.

17. The photomask for projection lithography according to claim 16, wherein: the photomask also comprises a phase shift material layer, the phase shift material layer is positioned between the transparent substrate and the shading layer, and the exposure window is stopped at the top surface of the phase shift material layer.

18. A method of manufacturing a photomask for projection lithography according to any of claims 16 to 17, comprising the steps of:

providing a light-transmitting substrate, wherein the light-transmitting substrate is provided with a first surface and a second surface which are opposite;

forming a surface plasma excimer layer on the first surface of the light-transmitting substrate;

providing a transparent substrate, wherein the transparent substrate is provided with a first surface and a second surface which are opposite, a shading layer is formed on the first surface of the transparent substrate, and an exposure window is formed in the shading layer;

and bonding the second surface of the light-transmitting substrate and the second surface of the transparent substrate.

19. A photomask for projection lithography, said photomask comprising:

and the shading layer covers the second surface of the light-transmitting substrate, and an exposure window penetrating through the shading layer is arranged in the shading layer.

20. The photomask for projection lithography according to claim 19, wherein: the photomask also comprises a phase shift material layer, the phase shift material layer is positioned between the light-transmitting substrate and the light shielding layer, and the exposure window is stopped at the top surface of the phase shift material layer.

21. A method of manufacturing a photomask for projection lithography according to any of claims 19 to 20, comprising the steps of:

and forming a light shielding layer on the second surface of the light-transmitting substrate, and forming an exposure window in the light shielding layer.