CN114791640B - Blazed grating and manufacturing method thereof - Google Patents
Blazed grating and manufacturing method thereof Download PDFInfo
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- CN114791640B CN114791640B CN202110099729.9A CN202110099729A CN114791640B CN 114791640 B CN114791640 B CN 114791640B CN 202110099729 A CN202110099729 A CN 202110099729A CN 114791640 B CN114791640 B CN 114791640B
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 39
- 239000000463 material Substances 0.000 claims abstract description 20
- 238000005530 etching Methods 0.000 claims description 77
- 238000000034 method Methods 0.000 claims description 59
- 229920002120 photoresistant polymer Polymers 0.000 claims description 44
- 239000000758 substrate Substances 0.000 claims description 34
- 238000010894 electron beam technology Methods 0.000 claims description 15
- 238000010884 ion-beam technique Methods 0.000 claims description 12
- 238000000576 coating method Methods 0.000 claims description 11
- 239000011248 coating agent Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052681 coesite Inorganic materials 0.000 claims description 3
- 229910052906 cristobalite Inorganic materials 0.000 claims description 3
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- 229920000642 polymer Polymers 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 235000012239 silicon dioxide Nutrition 0.000 claims description 3
- 229910052682 stishovite Inorganic materials 0.000 claims description 3
- 229910052905 tridymite Inorganic materials 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 22
- 238000010168 coupling process Methods 0.000 description 13
- 238000005859 coupling reaction Methods 0.000 description 13
- 230000008878 coupling Effects 0.000 description 12
- 230000003190 augmentative effect Effects 0.000 description 8
- 238000012544 monitoring process Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 6
- 230000001154 acute effect Effects 0.000 description 5
- 241001270131 Agaricus moelleri Species 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 229910001423 beryllium ion Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1847—Manufacturing methods
- G02B5/1857—Manufacturing methods using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
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Abstract
The embodiment of the application provides a blazed grating and a manufacturing method of the blazed grating, comprising the following steps: the base layer and blazed grating teeth are arranged on the base layer and are distributed periodically; the blazed grating teeth comprise a first grating part and a second grating part which are made of different materials, the blazed grating teeth are provided with blazed surfaces and blazed surfaces, the blazed surfaces are arranged on the first grating part, the blazed surfaces are arranged on the second grating part, and the connection parts of the blazed surfaces and the blazed surfaces form sharp angles at the tops of the blazed grating teeth. The embodiment of the application provides a blazed grating and a manufacturing method of the blazed grating, which can improve diffraction efficiency of the blazed grating.
Description
Technical Field
The application relates to the technical field of augmented reality equipment, in particular to a blazed grating and a manufacturing method of the blazed grating.
Background
The implementation mode of the optical system on the head-mounted augmented reality display can be a grating waveguide scheme, namely, a slab waveguide is adopted as a light transmission medium, and a grating is used as a waveguide coupling-in and coupling-out device so as to realize light propagation. Blazed gratings can concentrate incident light energy at a specific order, and can be used as coupling devices in grating waveguides, so that the coupling efficiency of the grating waveguides can be improved.
In the related art, the processing mode of the blazed grating is that the photoresist morphology is generated by using electron beam gray level direct writing, and then the photoresist morphology is transferred to the grating substrate in an etching mode, so that the blazed grating is manufactured.
However, when the gray level of the electron beam is directly written, the electron beam can scatter on the photoresist, so that the sharp angle at the top of the photoresist is very easy to etch, and therefore, the sharp angle at the top of the blazed grating is not ideal, even a round angle with a larger radius is formed, and the round angle can lead to the reduction of diffraction efficiency, so that the diffraction efficiency of the waveguide coupled into the grating is affected.
Disclosure of Invention
The embodiment of the application provides a blazed grating and a manufacturing method of the blazed grating, which can improve diffraction efficiency of the blazed grating.
In one aspect, an embodiment of the present application provides a blazed grating, including: the device comprises a basal layer and blazed grating teeth which are arranged on the basal layer and are periodically distributed; the blazed grating teeth comprise a first grating part and a second grating part, the first grating part and the second grating part are made of different materials, the blazed grating teeth are provided with blazed surfaces and anti-blazed surfaces, the blazed surfaces are arranged on the first grating part, the anti-blazed surfaces are arranged on the second grating part, and the connection parts of the blazed surfaces and the anti-blazed surfaces form sharp corners at the tops of the blazed grating teeth.
According to the blazed grating, the first grating part and the second grating part are arranged to jointly form the blazed grating teeth, the first grating part and the second grating part are respectively provided with the blazed surface and the blazed surface, and the blazed surface jointly form an ideal sharp angle, so that the blazed grating is close to an ideal blazed grating morphology, has higher diffraction efficiency, and can improve the coupling efficiency of the grating waveguide, thereby improving the energy utilization rate of the grating waveguide.
In one possible embodiment, a first angle between the blaze face and the base layer is between 30-70 degrees and a second angle between the blaze face and the base layer is between 85-90 degrees.
In a possible embodiment, an interface is formed between the first grating portion and the second grating portion, and a third included angle between the interface and the substrate layer is between 10 and 60 degrees.
In one possible embodiment, the refractive index of the first grating portion is 1.3-2.5, and the refractive index of the second grating portion is 1.3-2.0.
The refractive index of the material of the second grating portion and the material of the first grating portion may be the same or similar to ensure the performance of the blazed grating.
In one possible embodiment, the blazed grating has a grating period of 200-500nm.
In one possible embodiment, the first grating portion is made of SiO2 and the second grating portion is made of a polymer.
Another aspect of the embodiments of the present application provides a method for manufacturing a blazed grating, including:
providing a substrate layer, a grating layer and a grating mask which are arranged on the substrate layer, and etching the grating layer and the grating mask by adopting an oblique etching process to form a triangular first grating part on the grating layer, wherein the first grating part comprises a blazed surface and an interface, and a first included angle between the blazed surface and the substrate layer is smaller than a third included angle between the interface and the substrate layer;
forming a filling layer coating the first grating part;
and etching the filling layer by adopting a vertical etching process, reserving the filling layer between the interface and the substrate layer to form a second grating part, wherein the first grating part and the second grating part form blazed grating teeth.
According to the manufacturing method of the blazed grating, the first grating part and the second grating part are arranged to jointly form the blazed grating teeth, and as the first grating part and the second grating part are not affected by the round angle caused by direct writing of electron beam gray scales in the etching process, an ideal sharp angle can be formed at the top of the blazed grating teeth by controlling the etching ratio and the etching end point monitoring, so that the blazed grating is close to an ideal blazed grating morphology, and higher diffraction efficiency is achieved.
In one possible implementation manner, a fourth included angle is formed between the inclined ion beam corresponding to the inclined etching process and the substrate layer, and the value of the fourth included angle is between the first included angle and the third included angle.
The fourth included angle is set between the first included angle and the third included angle, so that a first grating part with a preset first included angle and a preset third included angle can be formed after the inclined ion beam is etched.
In one possible implementation manner, the etching the grating layer and the grating mask by using an oblique etching process specifically includes:
and selecting a preset etching ratio, and etching the grating layer and the grating mask to ensure that the grating layer and the grating mask are consumed simultaneously, and taking the light consumption of the grating mask as an etching termination point through the end point detection of the etching process.
By controlling the etching ratio and the etching end point monitoring, the top of the first grating part can form an ideal sharp angle, so that the diffraction efficiency of the blazed grating can be improved.
In one possible implementation manner, the method for manufacturing the blazed grating further comprises:
taking the blazed grating with the basal layer and the blazed grating teeth as a nano-imprinting female die to manufacture a nano-imprinting male die;
and manufacturing the blazed grating by taking the nano-imprinting male die as a die and adopting a nano-imprinting process.
The blazed grating manufactured by the nanoimprint process also has ideal sharp angles, and the blazed grating teeth are made of the same material, so that the blazed grating has better performance; the mass replication of the blazed grating can be realized through the nanoimprint technology, the manufacturing cost of the blazed grating is reduced, the mass production is excellent, and the application universality of the blazed grating can be improved.
In one possible embodiment, the providing a substrate layer, a grating layer disposed on the substrate layer, and a grating mask specifically includes:
providing a substrate layer, and coating a grating layer, a grating mask layer and a photoresist layer on the substrate layer in sequence;
using holographic exposure or electron beam direct writing to form a photoresist mask on the photoresist layer;
and etching the grating mask layer by using the photoresist mask, and transferring the morphology of the photoresist mask to the grating mask layer to form the grating mask.
In one possible embodiment, the forming a filling layer covering the first grating portion specifically includes:
and filling the first grating part by using a film plating or photoresist coating process to form a filling layer coating the first grating part.
The process of forming the filling layer is easy to realize, and the forming process of the filling layer does not influence the structure of the first grating portion.
In one possible embodiment, the etch rate of the filler layer is greater than the etch rate of the grating layer.
By controlling the etching ratio and the etching end point monitoring, the top of the second grating part can form an ideal sharp angle, so that the diffraction efficiency of the blazed grating can be improved.
According to the manufacturing method of the blazed grating and the blazed grating, the first grating part and the second grating part are arranged to form the blazed grating teeth together, and as the first grating part and the second grating part are not affected by the round angle caused by direct writing of electron beam gray scales in the etching process, and the top of the blazed grating teeth can form ideal sharp angles by controlling the etching ratio and the etching end point monitoring, the blazed grating is close to the ideal blazed grating morphology, the diffraction efficiency is higher, the coupling efficiency of the grating waveguide can be improved, and the energy utilization rate of the grating waveguide is improved.
Drawings
FIG. 1 is a schematic diagram of a grating waveguide according to the related art;
fig. 2 is a schematic structural view of a grating waveguide with blazed grating according to the related art;
FIG. 3 is a schematic diagram illustrating a method for fabricating a blazed grating according to the related art;
FIG. 4 is a second schematic process diagram of a method for fabricating a blazed grating according to the related art;
FIG. 5 is a schematic diagram of a blazed grating according to an embodiment of the present disclosure;
FIG. 6 is a schematic structural view of a substrate layer according to an embodiment of the present disclosure;
FIG. 7 is a schematic diagram of a structure for fabricating a photoresist mask according to one embodiment of the present application;
FIG. 8 is a schematic diagram of a structure for fabricating a grating mask according to an embodiment of the present disclosure;
FIG. 9 is a schematic diagram of an intermediate process of etching a grating layer according to an embodiment of the present disclosure;
FIG. 10 is a schematic diagram illustrating an intermediate process of fabricating a first grating portion according to an embodiment of the present disclosure;
FIG. 11 is a schematic structural diagram of a first grating portion according to an embodiment of the present disclosure;
FIG. 12 is a schematic diagram of a structure for fabricating a filling layer according to an embodiment of the present disclosure;
FIG. 13 is a schematic diagram of an intermediate process for fabricating a second grating portion according to an embodiment of the present disclosure;
fig. 14 is a blazed grating manufactured by a nanoimprint process according to an embodiment of the present application.
Reference numerals illustrate:
100-slab waveguide; 11-an in-coupling device; 200-blazed gratings; 21-a substrate layer; 22-blazed grating teeth; 221-a first grating section; 2211-blaze face; 222-a second grating portion; 2221—glint surface; 223-interface; 300-photoresist layer; 31-a photoresist mask; 400-grating layer; 500-grating mask layer; 51-grating mask; 600-filling layer; a1-a first included angle; a2-a second included angle; a3-a third included angle; a4-fourth included angle.
Detailed Description
Augmented reality (augmented reality, AR) technology is a technology that calculates the position and angle of an image emitted from a light engine system (also called a projector or an optical machine) in real time and adds a corresponding image. Because the augmented reality technology enables the virtual world to interact with the real world, the method is widely applied to augmented reality devices, such as AR glasses, head-mounted augmented reality displays and the like, and can project virtual images into human eyes to realize superposition of the virtual images and the real images.
The optical system of the AR device such as the head-mounted augmented reality display and the AR glasses has various architectures, such as a free-form surface scheme, a geometric array waveguide scheme, a grating waveguide scheme and other various technical paths. Fig. 1 is a schematic structural view of a grating waveguide provided in the related art, and fig. 2 is a schematic structural view of a grating waveguide provided in the related art with a blazed grating. Referring to fig. 1 and 2, the grating waveguide scheme uses a slab waveguide 100 as a light transmission medium, and uses a grating as a waveguide coupling-in device 11 and a coupling-out device to realize light propagation. After the incident light is incident on the coupling-in grating, diffraction occurs on the coupling-in grating, and part of energy is coupled into the light direction shown in the figure, and the light in the direction satisfies the total reflection condition and can travel back and forth in the slab waveguide 100.
The grating can comprise a surface relief grating or a holographic grating and the like, and the surface relief grating can be replicated in batches by a nanoimprint technology, so that the grating has excellent mass productivity and is widely applied.
The coupling device 11 of the grating waveguide may have various configurations, such as a rectangular grating, an inclined grating, a blazed grating, etc., and the blazed grating 200 has grating teeth of an asymmetric structure, which may concentrate the incident light energy on a certain specific order, and there are application requirements in many fields, when the blazed grating is used as the coupling device 11 in the grating waveguide, referring to fig. 2, the blazed grating 200 of an ideal morphology has a higher coupling efficiency, and may diffract the incident light more into a desired propagation direction.
Fig. 3 is a schematic process diagram of a method for manufacturing a blazed grating according to the related art, fig. 4 is a schematic process diagram of a second method for manufacturing a blazed grating according to the related art, and referring to fig. 3 and 4, in the related art, the blazed grating 200 is manufactured by directly writing a photoresist layer 300 with electron beam gray scale to form a shape identical to an ideal shape of the blazed grating 200, and then transferring the shape of the photoresist layer 200 to the grating layer 400 by etching.
However, when the gray scale of the electron beam is written directly, the electron beam will scatter on the photoresist 300, resulting in the diffusion of the focused electron beam spot, which results in the undesirable top sharp angle of the blazed grating 200, and even forms a rounded angle with a larger radius, the radius of the rounded angle is generally between 20 nm and 50nm, and the rounded angle will cause the decrease of diffraction efficiency, thereby affecting the diffraction efficiency of the coupling grating of the grating waveguide.
Based on the above problems, the embodiment of the application provides a blazed grating and a manufacturing method of the blazed grating, wherein the first grating part and the second grating part are arranged to form blazed grating teeth together, and as the first grating part and the second grating part are not affected by a round angle caused by direct writing of electron beam gray in the etching process, and the etching ratio and the etching end point monitoring are controlled, the top of the blazed grating teeth can form an ideal sharp angle, so that the blazed grating is close to an ideal blazed grating morphology, the diffraction efficiency is higher, the coupling efficiency of a grating waveguide can be improved, and the energy utilization rate of the grating waveguide is improved.
The structure of the blazed grating provided in the present application is described below with reference to the drawings and specific embodiments.
Fig. 5 is a schematic structural diagram of a blazed grating according to an embodiment of the present disclosure. Referring to fig. 5, in one aspect, the present embodiment provides a blazed grating 200, including a base layer 21 and blazed grating teeth 22 disposed on the base layer 21, where a plurality of blazed grating teeth 22 are periodically distributed.
The blazed grating teeth 22 include a first grating portion 221 and a second grating portion 222, the first grating portion 221 and the second grating portion 222 are made of different materials, the blazed grating teeth 22 have a blaze surface 2211 and a blaze surface 2221, the blaze surface 2211 is disposed on the first grating portion 221, the blaze surface 2221 is disposed on the second grating portion 222, and a junction of the blaze surface 2211 and the blaze surface 2221 forms a sharp corner at the top of the blazed grating teeth 22.
Wherein in some embodiments of the present application, a first angle a1 between the blaze surface 2211 and the substrate layer 21 is between 30-70 degrees and a second angle a2 between the blaze surface 2221 and the substrate layer 21 is between 85-90 degrees.
The first grating portion 221 and the second grating portion 222 form an interface 223 therebetween, and a third angle a3 between the interface 223 and the substrate layer 21 has a value between the first angle a1 and the second angle a2 within a range of 10-60 degrees.
The refractive index of the first grating portion 221 may be 1.3-2.5, and the refractive index of the second grating portion 222 may be 1.3-2.0. The refractive index of the material of the second grating portion 222 and the material of the first grating portion 221 may be the same or similar to ensure the performance of the blazed grating 200.
In the embodiment of the present application, the grating period of the blazed grating 200 may be 200-500nm.
Wherein the first grating portion 221 is made of SiO2 and the second grating portion 222 is made of a polymer.
According to the blazed grating, the first grating part and the second grating part are arranged to jointly form the blazed grating teeth, the first grating part and the second grating part are respectively provided with the blazed surface and the blazed surface, and the blazed surface jointly form an ideal sharp angle, so that the blazed grating is close to an ideal blazed grating morphology, has higher diffraction efficiency, and can improve the coupling efficiency of the grating waveguide, thereby improving the energy utilization rate of the grating waveguide.
The method for manufacturing the blazed grating provided by the application is described below with reference to the accompanying drawings and specific embodiments.
Fig. 6 is a schematic structural diagram of a substrate layer according to an embodiment of the present disclosure. Referring to fig. 6, a method for fabricating the blazed grating 200 may include: a base layer 21 is provided, and a grating layer 400, a grating mask layer 500, and a photoresist layer 300 are sequentially coated on the base layer 21.
The material of the base layer 21 is not particularly limited, and may be, for example, siO 2 And the like. The grating layer 400 is used to make blazed grating teeth 22 of the blazed grating 200, which may be made of SiO 2 And the like to improve the diffraction efficiency of the blazed grating 200. The grating mask layer 500 is used as a mask for etching the grating layer 400, and may be made of various materials such as Cr. The photoresist layer 300 is used to fabricate a photoresist mask for etching the grating mask layer 500, and the photoresist layer 300 may be made of an organic compound such as a photosensitive resin.
It will be appreciated that the thickness of the grating mask layer 500 may be not less than the thickness of the photoresist layer 300 so that the morphology of the photoresist mask formed after the photoresist layer 300 is etched may be completely transferred to the grating mask layer 500, and the thickness of the grating layer 400 may be not less than the thickness of the grating mask layer 500 so that the grating layer 400 may obtain blazed grating teeth 22 after the grating mask layer 500 is depleted of light.
The specific thickness ranges of the base layer 21, the grating layer 400, the grating mask layer 500, and the photoresist layer 300 may not be particularly limited in the embodiments of the present application. In some embodiments, the photoresist layer 300 may have a thickness ranging between 10-500nm, the grating mask layer 500 may have a thickness ranging between 10-200nm, and the grating layer 400 may have a thickness ranging between 10-800 nm.
Fig. 7 is a schematic structural diagram of a photoresist mask according to an embodiment of the present application. Referring to fig. 7, the photoresist layer 300 may be formed into the photoresist mask 31 shown in fig. 7 by exposure, development, or the like using a hologram exposure or electron beam direct writing method or the like on the basis of fig. 6.
The photoresist mask 31 includes a plurality of mask units arranged periodically, and the cross-sectional shape of the mask units may be rectangular or semicircular as shown in fig. 7, for example.
Fig. 8 is a schematic structural diagram of a grating mask according to an embodiment of the present application. Referring to fig. 8, the photoresist mask 31 is used to etch the grating mask layer 500 on the basis of fig. 7, and the morphology of the photoresist mask 31 is transferred onto the grating mask layer 500 to form the grating mask 51.
Specifically, the gate mask layer 500 is etched, and the etching process used may be ion beam etching or reactive ion beam etching. After transferring the morphology of the photoresist mask 31 onto the grating mask layer 500, the morphology of the formed grating mask 51 is nearly identical to the morphology of the photoresist mask 31. The grating mask 51 may also comprise a plurality of periodically arranged mask units, which may have a rectangular cross-sectional shape or a semicircular shape as shown in fig. 8, for example.
In this embodiment, the photoresist layer 300 is used to manufacture the photoresist mask 31, and then the photoresist mask 31 is used to manufacture the grating mask 51 to obtain the grating mask 51 with a preset shape, so that the manufacturing process is simple, the structure of the grating mask 51 with a wider size and shape range can be obtained, the size range and shape range of the blazed grating 200 can be expanded, and the applicability of the blazed grating 200 can be improved.
In another possible embodiment, the grating mask layer 500 may also be etched directly, resulting in the grating mask 51 shown in fig. 8. At this time, the manufacturing steps of the blazed grating 200 can be saved, the production efficiency can be improved, and the production cost can be saved.
Fig. 9 is a schematic structural diagram of an intermediate process of etching a grating layer according to an embodiment of the present application, fig. 10 is a schematic structural diagram of an intermediate process of manufacturing a first grating portion according to an embodiment of the present application, and fig. 11 is a schematic structural diagram of the first grating portion according to an embodiment of the present application. Referring to fig. 9 to 11, on the basis of providing the base layer 21, the grating layer 400 and the grating mask 51 provided on the base layer 21 in fig. 8, the grating layer 400 and the grating mask 51 may be etched using an oblique etching process such that the grating layer 400 forms the triangular first grating portion 221.
The first grating portion 221 includes a blaze surface 2211 and an interface 223, where the blaze surface 2211, the interface 223 and the upper surface of the substrate layer 21 together enclose a triangle, the triangle is an obtuse triangle, an angle formed by the blaze surface 2211 and the interface 223 is a vertex angle of the triangle first grating portion 221, the vertex angle is an acute angle smaller than 90 degrees, a first included angle a1 between the blaze surface 2211 and the substrate layer 21 is one base angle of the triangle first grating portion 221, the base angle is an acute angle smaller than 90 degrees, a complementary angle of a third included angle a3 between the interface 223 and the substrate layer 21 is another base angle of the triangle first grating portion 221, and the base angle is an obtuse angle.
The first included angle a1 and the third included angle a3 are acute angles and are oriented consistently. The first angle a1 between the interface 223 and the blaze surface 2211 of the upper surface of the base layer 21 and the base layer 21 may be smaller than the third angle a3 between the interface 223 and the base layer 21 to satisfy the obtuse triangle configuration. In one possible embodiment, the first angle a1 between the blaze surface 2211 and the substrate layer 21 is between 30-70 degrees and the third angle a3 between the interface 223 and the substrate layer 21 is between 10-60 degrees.
The etching of the grating layer 400 and the grating mask 51 by using an oblique etching process specifically includes: the grating layer 400 and the grating mask 51 are etched by selecting a preset etching ratio, and the adopted etching process can be ion beam etching or reactive ion beam etching, so that the grating layer 400 and the grating mask 51 are consumed simultaneously, and the light consumption of the grating mask 51 is used as an etching termination point through the end point detection of the etching process.
Illustratively, the grating layer 400 may be SiO 2 The grating mask 51 mayAt this time, the simultaneous elimination of the two materials can be realized by adjusting the components of the etching gas, and the etching selection ratio of the two materials can be controlled by controlling the etching parameters such as the components of the gas and the like.
Referring to fig. 8 to 9, when the oblique ion beam current corresponding to the oblique etching process extends from top left to bottom right as indicated by the arrow in the figure, since the grating layer 400 and the grating mask 51 are consumed simultaneously and oblique etching is adopted, the etching of the grating layer 400 on the left side of the mask unit of the grating mask 51 is faster than the etching of the grating layer 400 on the right side, and the included angle of the left side with respect to the base layer 21 is larger than the included angle of the right side with respect to the base layer 21. Near the end of the etching process, as shown in fig. 10, when the grating mask 51 consumes light, the etching is terminated, as shown in fig. 11, resulting in a first grating portion 221 having sharp corners.
The inclined ion beam corresponding to the inclined etching process forms a fourth included angle a4 with the substrate layer 21, and the value of the fourth included angle a4 is between the first included angle a1 and the third included angle a3, so that the first grating portion 221 having the preset first included angle a1 and the third included angle a3 can be formed after the inclined ion beam is etched. In one possible embodiment, the fourth angle a4 may have a value close to one half of the sum of the first angle a1 and the third angle a 3.
Fig. 12 is a schematic structural diagram of a manufacturing filling layer according to an embodiment of the present application. Referring to fig. 12, in addition to the structure of the base layer 21 having the first grating portion 211 provided in fig. 11, the method of manufacturing the blazed grating 200 may further include forming a filling layer 600 covering the first grating portion 221.
The forming of the filling layer 600 covering the first grating 221 may specifically include:
the first grating portion 221 is filled using a plating film or a photoresist coating process to form a filling layer 600 covering the first grating portion 221.
The filling layer 600 on the base layer 21 has a height higher than that of the first grating portion 221 to entirely cover the first grating portion 221. The material of the filling layer 600 is not particularly limited in the embodiment of the present application, and in order to achieve etching, the etching speed of the filling layer 600 may be set to be greater than that of the first grating portion 221, that is, the filling layer 600 has a sufficiently high etching selectivity with respect to the grating layer 400. The desired coating material or photoresist material may be obtained by adding high refractive index particles to the polymer material, for example.
Fig. 13 is a schematic structural diagram of an intermediate process of fabricating the second grating portion according to an embodiment of the present application. Referring to fig. 13, the next step in the manufacturing method of the blazed grating 200 may be to etch the filling layer 600 by a vertical etching process, so as to leave the filling layer 600 between the interface 223 and the base layer 21 to form the second grating portion 222, and the first grating portion 221 and the second grating portion 222 form the blazed grating teeth 22, as shown in fig. 5.
As shown by the arrow direction in fig. 13, the ion beam vertically etched can retain the morphology of the first grating portion 221 and obtain the second grating portion 222 when the material removal in the vertical direction is performed due to the directionality of the ion beam and the high etching selectivity of the grating layer of the first grating portion 221 to the filling layer 600.
The second grating portion 222 includes an anti-blazed surface 2221, and the second grating portion 222 is a triangle formed by the filler layer 600, and the interface 223, the anti-blazed surface 2221, and the upper surface of the base layer 21 together define a triangle, which approximates to a right triangle. The angle formed by the blaze reflecting surface 2221 and the interface surface 223 is an acute angle smaller than 90 degrees, the third angle a3 between the interface surface 223 and the base layer 21 is one base angle of the triangular second grating portion 222, the complementary angle of the second angle a2 between the blaze reflecting surface 2221 and the base layer 21 is the other base angle of the triangular second grating portion 222, and the base angle is close to a right angle.
It should be noted that, the first included angle a1 and the third included angle a3 are acute angles, and the directions of the first included angle a1, the second included angle a2 and the third included angle a3 are consistent. In one possible embodiment, the second angle a2 between the blaze surface 2221 and the base layer 21 is between 85-90 degrees, i.e. around 90 degrees.
The first grating portion 221 and the second grating portion 222 together constitute blazed grating teeth 22, and the blazed surface 2211 of the first grating portion 221 and the blazed surface 2221 of the second grating portion 222 constitute sharp corners at the top of the blazed grating teeth 22. Since the first grating part 221 and the second grating part 222 are not affected by the rounded angle caused by the direct writing of the electron beam gray scale in the etching process, and the top of the blazed grating teeth 22 can form an ideal sharp angle by controlling the etching ratio and the etching end point monitoring, the diffraction efficiency of the blazed grating 200 can be improved.
In one possible embodiment, the blazed grating 200 manufactured by the above manufacturing steps may be directly used as the coupling device 11 of the grating waveguide, and the refractive index of the material of the second grating portion 222 and the refractive index of the material of the first grating portion 221 may be the same or similar, so as to ensure the performance of the blazed grating 200.
In another possible embodiment, the blazed grating 200 manufactured by the above steps can be used to produce nano-imprint templates to realize mass production of the blazed grating 200. In the present embodiment, the refractive index of the second grating portion 222 is not particularly limited, and the refractive index of the first grating portion 221 may be 1.3 to 2.5 and the refractive index of the second grating portion 222 may be 1.3 to 2.0, for example.
On the basis of the above embodiment, in the embodiment of the present application, the method for manufacturing a blazed grating may further include the following steps:
a first step of manufacturing a nanoimprint male mold by using a blazed grating 200 having a base layer 21 and blazed grating teeth 22 as a nanoimprint female mold;
in the second step, the blazed grating 200 is manufactured by using the nano-imprint male mold as a mold and adopting a nano-imprint process.
Fig. 14 is a blazed grating manufactured by a nanoimprint process according to an embodiment of the present application. Referring to fig. 14, the blazed grating 200 manufactured by the nanoimprint process has a blazed surface 2211 and a blazed surface 2221, and the outer contour of the blazed grating teeth 22 is identical to the outer contour of the blazed grating teeth 200 in fig. 5, and has ideal sharp angles. In contrast, blazed grating teeth 200 are made of the same material and have better performance.
In addition, in the embodiment of the application, the batch replication of the blazed grating 200 can be realized by the nanoimprint technology, so that the manufacturing cost of the blazed grating 200 is reduced, the mass productivity is excellent, and the application universality of the blazed grating 200 can be improved.
According to the manufacturing method of the blazed grating and the blazed grating, the first grating part and the second grating part are arranged to form the blazed grating teeth together, and as the first grating part and the second grating part are not affected by the round angle caused by direct writing of electron beam gray scales in the etching process, and the top of the blazed grating teeth can form ideal sharp angles by controlling the etching ratio and the etching end point monitoring, the blazed grating is close to the ideal blazed grating morphology, the diffraction efficiency is higher, the coupling efficiency of the grating waveguide can be improved, and the energy utilization rate of the grating waveguide is improved.
In the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, indirectly connected via an intermediate medium, or capable of communicating between two elements or of interacting between two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances. The terms first, second, third and the like in the description and in the claims of the embodiments and in the above-described figures are used for other similar objects and are not necessarily used for describing a particular order or sequence.
Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although embodiments of the present application have been described in detail with reference to the foregoing embodiments, it will be appreciated by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions.
Claims (9)
1. A blazed grating comprising: the device comprises a basal layer and blazed grating teeth which are arranged on the basal layer and are periodically distributed;
the blazed grating teeth comprise a first grating part and a second grating part, the first grating part and the second grating part are made of different materials, the blazed grating teeth are provided with blazed surfaces and anti-blazed surfaces, the blazed surfaces are arranged on the first grating part, the anti-blazed surfaces are arranged on the second grating part, and the connection parts of the blazed surfaces and the anti-blazed surfaces form sharp corners at the tops of the blazed grating teeth;
a first included angle between the blaze face and the base layer is between 30 and 70 degrees, and a second included angle between the blaze face and the base layer is between 85 and 90 degrees;
the refractive index of the first grating part is 1.3-2.5, and the refractive index of the second grating part is 1.3-2.0.
2. A blazed grating according to claim 1, wherein an interface is formed between the first grating portion and the second grating portion, and a third angle between the interface and the substrate layer is between 10-60 degrees.
3. A blazed grating as recited in any one of claims 1-2, wherein the blazed grating has a grating period of 200-500nm.
4. Blazed grating according to any one of claims 1-2, wherein the first grating portion is made of SiO2 and the second grating portion is made of a polymer.
5. A method of fabricating a blazed grating, comprising:
providing a substrate layer, a grating layer and a grating mask which are arranged on the substrate layer, and etching the grating layer and the grating mask by adopting an oblique etching process to form a triangular first grating part on the grating layer, wherein the first grating part comprises a blazed surface and an interface, and a first included angle between the blazed surface and the substrate layer is smaller than a third included angle between the interface and the substrate layer;
forming a filling layer coating the first grating part;
etching the filling layer by adopting a vertical etching process, and reserving the filling layer between the interface and the basal layer to form a second grating part, wherein the first grating part and the second grating part form blazed grating teeth;
the etching speed of the filling layer is larger than that of the grating layer;
the etching of the grating layer and the grating mask by adopting an oblique etching process specifically comprises:
and selecting a preset etching ratio, and etching the grating layer and the grating mask to ensure that the grating layer and the grating mask are consumed simultaneously, and taking the light consumption of the grating mask as an etching termination point through the end point detection of the etching process.
6. The method of claim 5, wherein a fourth included angle is formed between the oblique ion beam corresponding to the oblique etching process and the substrate layer, and the fourth included angle is between the first included angle and the third included angle.
7. A method of producing a blazed grating as recited in claim 5, further comprising:
taking the blazed grating with the basal layer and the blazed grating teeth as a nano-imprinting female die to manufacture a nano-imprinting male die;
and manufacturing the blazed grating by taking the nano-imprinting male die as a die and adopting a nano-imprinting process.
8. The method for producing a blazed grating according to any one of claims 5 to 7, wherein the providing a substrate layer, a grating layer disposed on the substrate layer, and a grating mask, comprises:
providing a substrate layer, and coating a grating layer, a grating mask layer and a photoresist layer on the substrate layer in sequence;
using holographic exposure or electron beam direct writing to form a photoresist mask on the photoresist layer;
and etching the grating mask layer by using the photoresist mask, and transferring the morphology of the photoresist mask to the grating mask layer to form the grating mask.
9. The method of manufacturing a blazed grating according to any one of claims 5 to 7, wherein the forming of the filling layer coating the first grating portion comprises:
and filling the first grating part by using a film plating or photoresist coating process to form a filling layer coating the first grating part.
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| CN202110099729.9A CN114791640B (en) | 2021-01-25 | 2021-01-25 | Blazed grating and manufacturing method thereof |
| PCT/CN2022/070323 WO2022156536A1 (en) | 2021-01-25 | 2022-01-05 | Blazed grating and manufacturing method for blazed grating |
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| CN202110099729.9A CN114791640B (en) | 2021-01-25 | 2021-01-25 | Blazed grating and manufacturing method thereof |
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| CN1576903A (en) * | 2003-07-09 | 2005-02-09 | Asml荷兰有限公司 | Mirror and lithographic apparatus with mirror |
| US7175773B1 (en) * | 2004-06-14 | 2007-02-13 | Carl Zeiss Laser Optics Gmbh | Method for manufacturing a blazed grating, such a blazed grating and a spectrometer having such a blazed grating |
| CN103257383A (en) * | 2013-04-16 | 2013-08-21 | 华中科技大学 | Preparation method of blazing-angle-variable blazed grating and double-blazed grating and products |
| CN103901520A (en) * | 2014-04-23 | 2014-07-02 | 中国科学技术大学 | Method for manufacturing triangular groove echelon gratings with 90-degree vertex angles |
| CN110082847A (en) * | 2019-04-29 | 2019-08-02 | 重庆大学 | A kind of preparation method of silicon substrate MEMS balzed grating, |
| CN110244395A (en) * | 2019-06-28 | 2019-09-17 | 中国科学技术大学 | A kind of production method of the double angle balzed grating,s of plane |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4310080B2 (en) * | 2002-06-17 | 2009-08-05 | キヤノン株式会社 | Diffractive optical element and optical system and optical apparatus provided with the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1576903A (en) * | 2003-07-09 | 2005-02-09 | Asml荷兰有限公司 | Mirror and lithographic apparatus with mirror |
| US7175773B1 (en) * | 2004-06-14 | 2007-02-13 | Carl Zeiss Laser Optics Gmbh | Method for manufacturing a blazed grating, such a blazed grating and a spectrometer having such a blazed grating |
| CN103257383A (en) * | 2013-04-16 | 2013-08-21 | 华中科技大学 | Preparation method of blazing-angle-variable blazed grating and double-blazed grating and products |
| CN103901520A (en) * | 2014-04-23 | 2014-07-02 | 中国科学技术大学 | Method for manufacturing triangular groove echelon gratings with 90-degree vertex angles |
| CN110082847A (en) * | 2019-04-29 | 2019-08-02 | 重庆大学 | A kind of preparation method of silicon substrate MEMS balzed grating, |
| CN110244395A (en) * | 2019-06-28 | 2019-09-17 | 中国科学技术大学 | A kind of production method of the double angle balzed grating,s of plane |
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| WO2022156536A1 (en) | 2022-07-28 |
| CN114791640A (en) | 2022-07-26 |
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