CN111352304B - Focusing and leveling device, photoetching equipment and focusing and leveling method - Google Patents

Focusing and leveling device, photoetching equipment and focusing and leveling method Download PDF

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CN111352304B
CN111352304B CN201811583111.4A CN201811583111A CN111352304B CN 111352304 B CN111352304 B CN 111352304B CN 201811583111 A CN201811583111 A CN 201811583111A CN 111352304 B CN111352304 B CN 111352304B
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substrate
unit
light
focusing
leveling device
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CN111352304A (en
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毛静超
徐荣伟
庄亚政
孙建超
季桂林
李淑蓉
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Shanghai Micro Electronics Equipment Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/7085—Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70216—Mask projection systems
    • G03F7/70258—Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7023—Aligning or positioning in direction perpendicular to substrate surface
    • G03F9/7026—Focusing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7023—Aligning or positioning in direction perpendicular to substrate surface
    • G03F9/7034—Leveling

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  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
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  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)

Abstract

The invention relates to a focusing and leveling device, a photoetching device and a focusing and leveling method.A light ray emitted by a light source module is incident on a reflecting slit unit through an illuminating module, is reflected by the reflecting slit unit and then is projected onto a substrate through a projection unit, the light ray reflected by the substrate is imaged onto a detection module through an imaging unit, and the detection module processes the received light ray to obtain the position information of the substrate. The invention breaks through the dependence of the measuring mark on the slit material, and is beneficial to greatly improving the energy utilization rate of the focusing and leveling device and improving the detection signal-to-noise ratio.

Description

Focusing and leveling device, photoetching equipment and focusing and leveling method
Technical Field
The invention relates to the field of semiconductor equipment, in particular to a focusing and leveling device, photoetching equipment and a focusing and leveling method.
Background
A projection lithography machine is a device which images a mask pattern through a projection objective onto, for example, a substrate surface, a glass substrate or an LED. In order to ensure accurate exposure of the mask pattern, the surface of the substrate needs to be accurately controlled to a specified position by the focusing and leveling device. And judging whether the surface of the substrate is correctly focused and leveled by detecting the height and the inclination information of the bottom surface of the lining in the exposure field, and further adjusting the position of the workpiece table according to the measurement result to enable the surface of the substrate on the workpiece table to be positioned at the optimal focal plane of the projection objective.
In order to obtain the height and inclination information of the substrate surface in the entire exposure field, a plurality of measurement marks are provided in the exposure field, and the position information of the entire substrate surface is obtained by detecting the height and inclination information of the measurement marks. In the current focusing and leveling device, the measurement mark is mostly disposed on the transmission slit flat plate or the combination of the transmission slit and the prism. However, in the current focusing and leveling device, the transmission slit needs to depend on the substrate material, which limits the transmission band, on one hand, the current substrate material has higher transmittance only in the band of 0.2 μm to 1.25 μm, and the transmittance in other bands is lower; on the other hand, when the wavelength band is larger than 0.3 μm, the chromatic aberration is large. In addition, the energy loss of the transmitted wave obliquely incident to the slit surface needs to be considered in the transmission slit flat plate or the transmission slit and prism assembly, and when the light rays are incident to the transmission slit flat plate or the transmission slit and prism assembly at an angle of more than 80 degrees, the energy loss of the transmitted wave is large, so that the detection signal-to-noise ratio of the focusing and leveling device is greatly reduced.
Disclosure of Invention
The invention aims to provide a focusing and leveling device, a photoetching device and a focusing and leveling method, which can overcome the dependence of a measuring mark on a transmission slit substrate material, avoid the limitation on the transmission wave band of the substrate material by adopting a reflection slit and are beneficial to improving the energy utilization rate and the detection signal-to-noise ratio of the focusing and leveling device.
In order to achieve the above object, the present invention provides a focusing and leveling device for detecting position information of a substrate, including a light source module, an illumination module, a reflective slit unit, a projection unit, an imaging unit, and a detection module, wherein light emitted from the light source module is incident on the reflective slit unit through the illumination module, reflected by the reflective slit unit and then projected onto a substrate through the projection unit, the light reflected from the substrate is imaged onto the detection module through the imaging unit, and the detection module processes the received light to obtain position information of the substrate.
Optionally, the reflective slit unit is located at the stop positions of the illumination module and the projection unit.
Optionally, a plurality of mark regions are disposed on the reflection slit unit, and the mark regions are plated with reflection films.
Optionally, an included angle between the light incident on the reflection slit unit and the reflection slit unit is smaller than 90 degrees.
Optionally, the reflective slit unit and the substrate satisfy the following conditions:
tanω＝ma tan(90°-δ)
wherein δ is an angle between the light and the reflective slit unit, ω is an incident angle of the light to the substrate, and maIs the imaging magnification of the projection unit.
Optionally, the light source module includes a point light source, a coupling light path and an optical fiber, and light emitted by the point light source sequentially passes through the coupling light path and the optical fiber and reaches the exit end of the optical fiber.
Optionally, the illumination module includes an illumination mirror group and a plane mirror, and the light passes through the illumination mirror group and the plane mirror and then enters the reflection slit unit.
Optionally, the projection unit includes a scanning mirror and a plurality of projection mirror groups, and the scanning mirror is disposed at a stop position of the projection unit and driven by a driver to perform scanning swing so as to project light reflected by the reflective slit unit onto the substrate.
Optionally, the imaging unit includes a plurality of imaging lens groups to image the light reflected by the substrate onto the detection module.
Optionally, the detection module is a photodetector.
Optionally, the detection module and the substrate satisfy the following conditions:
tan(90°-ζ)＝mb tanω
zeta is an included angle between the light ray and the detection module, omega is an incident angle of the light ray to the substrate, and mbIs the imaging magnification of the imaging unit.
The invention also provides a lithographic apparatus comprising the focusing and leveling device and a projection objective as described above, wherein the projection objective is located above a substrate.
The invention also provides a focusing and leveling method, which adopts the focusing and leveling device and comprises the following steps:
the light source module emits a light ray to the reflection slit unit through the illumination module;
the projection unit projects the light reflected by the reflection slit unit onto a substrate;
the imaging unit images the light reflected by the substrate onto a detection module, and the detection module processes the received light to obtain the position information of the substrate.
By adopting the reflection slit unit, the invention breaks through the dependence of the measurement mark on the slit material, provides larger selection space for the substrate material, and is beneficial to greatly improving the energy utilization rate of the focusing and leveling device and the signal to noise ratio of detection.
Drawings
FIG. 1 is a schematic structural diagram of a transmissive slit and prism assembly;
FIG. 2 is a schematic representation of the Scheimpflug conditions;
FIG. 3a is a graph of the total transmittance of a transmissive slit and prism assembly;
FIG. 3b is a graph of the total transmittance of a transmissive slit plate;
FIG. 4 is a schematic structural diagram of a focusing and leveling device according to an embodiment of the present invention;
FIG. 5a is a schematic structural diagram of a reflective slit unit;
FIG. 5b is a graph of the reflectivity of the EUV reflective film;
FIG. 5c is a graph of reflectance curves for various reflective films over a wavelength band of 0.5 μm to 0.8 μm;
fig. 6 is a schematic structural diagram of a focusing and leveling device according to a first embodiment of the present invention;
fig. 7 is a schematic structural diagram of a focusing and leveling device according to a second embodiment of the present invention;
in the figure:
101 a-a prism assembly; 102 a-a marker region; 103 a-incident wave; 104 a-transmitted wave;
102 b-a marker region; 103 b-incident wave; 104 b-reflected wave;
1-a light source module; 2-a lighting module; 21-an illumination lens group; 22-a plane mirror; 3-a reflective slit unit; 4-a projection unit; 5-an imaging unit; 6-a detection module; 7-a projection objective; 8-a substrate;
11-a light source module; 12-a lighting module; 121-an illumination lens group; 122-a plane mirror; 13-a reflective slit unit; 14-a projection unit; 141-front group of projection lens group; 142-a scanning mirror; 143-rear group of projection lens group; 15-an imaging unit; 151-front group of imaging lens group; 152-imaging mirror group diaphragm; 153-rear group of imaging lens group; 16-a detection module; 17-a projection objective; 18-a substrate;
21-a light source module; 22-a lighting module; 221-an illumination mirror group; 222-a plane mirror; 23-a reflective slit unit; 24-a projection unit; 241-front group of projection lens group; 242-a scanning mirror; 243-rear group of projection lens group; 25-an imaging unit; 251-front group of imaging lens group; 252-imaging mirror group diaphragm; 253-rear group of imaging lens group; 26-a detection module; 27-a projection objective; 28-substrate.
Detailed Description
The following describes in more detail embodiments of the present invention with reference to the schematic drawings. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
As mentioned in the background, in the current focusing and leveling device, the measurement mark is mostly disposed on the transmission slit flat plate or the combination of the transmission slit and the prism. However, in the current focusing and leveling device, the transmission slit needs to depend on the substrate material, and the substrate material limits the transmission waveband. The substrate material is required to have stable physical and chemical properties, the common fused quartz has high transmittance only in the wavelength range of 0.2-1.25 μm, and the transmittance in other wavelength ranges is low; on the other hand, when the wavelength band is larger than 0.3 μm, the chromatic aberration is large.
In addition, the transmissive slit plate or the transmissive slit and prism assembly also needs to consider the energy loss of the transmitted wave obliquely incident to the slit surface. Fig. 1 is a schematic structural diagram of a transmissive slit and prism assembly 101 a. As shown in fig. 1, the prism assembly 101a is made of fused silica and has a plurality of transparent mark areas 102a, and the energy relationship between the incident wave 103a and the transmitted wave 104a can be obtained according to the fresnel formula:
Figure BDA0001918393000000041
Figure BDA0001918393000000042
wherein, tausIs the transmittance, τ, of the s-wave component of the incident wave 103apTransmittance of p-wave as component of incident wave 103a, n1For the refractive index of fused silica, the total transmittance τ is expressed as (τ) for the case of incident natural lights+τp)/2。
According to the currently known application of transmission slits, in order to improve the sensitivity of the measurement and to reduce the influence of the process film layer on the measurement result, an imaging system complying with the Scheimpflug condition is usually adopted, i.e. the transmission slit is at an angle (not equal to 90 °) to the optical axis and is imaged on the surface of a substrate such as a silicon wafer at a larger incident angle. The Scheimpflug condition is shown in fig. 2, and the relationship between the inclination angle α of the object plane and the inclination angle β of the image plane is related to the magnification m of the optical system, and satisfies the following formula:
Figure BDA0001918393000000051
the exit angle of the light ray at the transmission slit surface is theta according to the application2Wherein 80 DEG < theta2< 90 DEG, from fused silica refractive index n at different wavelengths1Angle of refraction theta2The angle of incidence θ can be calculated from the law of refraction1Further calculating from the above formula to obtain τs、τp. Thus, when the light is vertically incident on the prism, the light is refracted by the angle theta2The total transmittance τ of the entire transmissive slit and the prism assembly upon exiting the transmissive slit has a value between 0% and 60%. From the calculated data, the refraction angle in air theta2The larger the total transmittance τ is. When angle of refraction theta2At 85 deg., the total transmittance at each wavelength band is shown in fig. 3a, and the total transmittance tau of the entire transmissive slit and prism assembly is between 40.5% and 43.5%.
Similarly, when the light ray is at the refraction angle theta2When the light exits from the flat plate with the transmission slit, the whole transmission slit is narrowThe total transmittance of the slit plate is between 0 and 39 percent. When angle of refraction theta2At 85 deg., the total transmittance at each wavelength band is shown in FIG. 3b, and the total transmittance tau of the whole transmissive slit plate is between 16% and 20%.
The substrate material of the visible transmission slit limits the transmission wave band, when light is incident to the transmission slit flat plate or the transmission slit and prism assembly at an angle larger than 80 degrees, the energy loss is large, the total transmittance is small, and the detection signal-to-noise ratio of the focusing and leveling device is greatly reduced.
Based on the above research, the present embodiment provides a focusing and leveling device, as shown in fig. 4, the focusing and leveling device is configured to detect position information of a substrate 8, and includes a light source module 1, a lighting module 2, a reflection slit unit 3, a projection unit 4, an imaging unit 5, and a detection module 6, light emitted by the light source module 1 is incident on the reflection slit unit 3 through the lighting module 2, is reflected by the reflection slit unit 3 and then is projected onto the substrate 8 through the projection unit 4, light reflected by the substrate is imaged onto the detection module 6 through the imaging unit 5, and the detection module 6 processes the received light to obtain position information of the substrate 8.
Specifically, light emitted by the light source module 1 is incident on the reflection slit unit 3 through the illumination module 2, the projection unit 4 projects the light reflected by the reflection slit unit 3 onto the substrate 8, the substrate 8 is located right below a projection objective 7, the projection unit 4 enables the light reflected by the substrate 8 to be imaged on the detection module 6 through the imaging unit 5 after the light is reflected by the substrate 8, and the detection module 6 processes information to obtain the accurate position of the substrate 8.
The light source module 1 includes, for example, a point light source, a coupling light path and an optical fiber, and light emitted from the point light source sequentially passes through the coupling light path and the optical fiber and reaches the exit end of the optical fiber. The coupling optical path can comprise a coupling lens group and a filter plate, and is used for improving the optical coupling efficiency and selecting the working waveband required by the focusing and leveling device.
The illumination module 2 includes, for example, an illumination mirror group 21 and a plane mirror 22, and the light passes through the illumination mirror group 21 and is reflected by the plane mirror 22, and finally enters the reflection slit unit 3. The lighting lens group 21 includes a collimating lens group and a stray light eliminating diaphragm, the collimating lens group is used for collimating the light emitted by the light source module, and the stray light eliminating diaphragm is used for eliminating part of stray light.
The projection unit 4 includes, for example, a scanning mirror and a plurality of projection lens groups, and the scanning mirror is disposed at a stop position of the projection unit 4 and driven by a driver to perform scanning swing so as to project the light reflected by the reflective slit unit 3 onto the substrate 8. Specifically, the scanning mirror slightly rotates around a fixed shaft in a clockwise direction or a counterclockwise direction under the driving of the driver, so as to project the light onto different positions on the substrate 8.
The imaging unit 5 for example comprises several imaging lens groups to image the light reflected by the substrate 8 onto the detection module 6.
Further, a plurality of mark regions 102b are disposed on the reflection slit unit 3, and the mark regions 102b are plated with a reflection film. The mark area on the reflective slit unit 3 is a mark area required for detecting information on the height and inclination of the substrate 8, and the mark area may be generally rectangular, and is not limited in number, size, and arrangement layout, and the number of the mark areas may be plural, and the size and arrangement layout of the mark areas may be various. Referring to fig. 5a, 5b and 5c, in fig. 5a, the mark regions 102b are arranged in 2 rows, each row has 6 lines, light enters the mark region 102b of the reflective slit unit 3, and the incident wave 103b is reflected to form a reflected wave 104 b. The reflection slit unit 3 is plated with a reflection film in the mark area 102b, according to the mature process at present, refer to fig. 5b, in which k is a reflection rate curve of the far ultraviolet reflection film, and the reflection rate of the far ultraviolet reflection film at the wave band of 0.17-11 μm is greater than 85%; referring to fig. 5c, reflectance curves of various reflective films at a wavelength band of 0.5 to 0.8 μm are shown, wherein a is a reflectance curve of an aluminum film, b is a reflectance curve of a gold film, c is a reflectance curve of a silver film, d is a reflectance curve of a super-wide multilayer electrolyte film, e is a reflectance curve of a 500nm wide band multilayer electrolyte film, f is a reflectance curve of a 600nm wide band multilayer electrolyte film, g is a reflectance curve of a 405nm multilayer electrolyte film for laser, h is a reflectance curve of a 500nm multilayer electrolyte film for laser, and i is a reflectance curve of a 670nm multilayer electrolyte film for laser. It can be seen that the reflectivity of the silver film in the wave band of 0.5-0.8 μm is more than 98%. The reflection slit unit 3 is not coated with a reflection film in the other region than the mark region 102b, and may be coated with a reflection reducing coating such as a black matting paint. The reflected light can be reduced in various ways, and the selection of the base material is independent of the working wavelength of the focusing and leveling device.
An included angle δ between the light incident on the reflection slit unit 3 and the reflection slit unit 3 is smaller than 90 degrees, so that energy loss of transmitted waves incident on a slit surface by incident waves is reduced. The reflective slit unit 3 and the substrate 8 satisfy the following conditions:
tanω＝matan (90 ° - δ) formula (1)
In formula (1), δ is an angle between the light ray and the reflective slit unit 3, ω is an incident angle of the light ray incident on the substrate 8, and maIs the imaging magnification of the projection unit 4.
Specifically, the reflection slit unit 3 is located at the stop positions of the illumination module 2 and the projection unit 4, and is also located at the object plane position between the illumination module 2 and the substrate 8. An included angle delta between the reflection slit unit 3 and the light incident on the reflection slit unit 3 is smaller than 90 degrees, and the reflection slit unit 3 and the substrate 8 meet the Scheimpflug condition.
The detection module 6 is, for example, a photodetector, and is configured to convert the received optical signal into an electrical signal for information processing. Further, the detection module 6 and the substrate 8 satisfy the following conditions:
tan(90°-ζ)＝mbtan omega equation (2)
In formula (2), ζ is an angle between the light and the detection module 6, and ω is an angle at which the light is incidentAngle of incidence, m, to said substrate 8bIs the imaging magnification of the imaging unit 5.
That is, the detection module 6 and the substrate 8 satisfy the Scheimpflug condition.
Further, the invention also provides a lithographic apparatus comprising the focusing and leveling device and a projection objective as described above, wherein the projection objective is located above a substrate. And the surface of the substrate on the workpiece table is positioned at the optimal focal plane of the projection objective by the focusing and leveling device.
Further, the present invention also provides a focusing and leveling method, which adopts the above-mentioned focusing and leveling device, and includes:
the light source module emits a light ray to the reflection slit unit through the illumination module;
the projection unit projects the light reflected by the reflection slit unit onto a substrate;
the imaging unit images the light reflected by the substrate onto a detection module, and the detection module processes the received light to obtain the position information of the substrate.
Referring to fig. 6, which is a schematic structural diagram of a focusing and leveling device according to an embodiment of the present invention, the structure in fig. 4 is further refined, and the focusing and leveling device includes a light source module 11, an illumination module 12, a reflection slit unit 13, a projection unit 14, an imaging unit 15, and a detection module 16, and is applicable to a visible light near-infrared band. The illumination module 12 includes an illumination mirror group 121 and a plane mirror 122, the projection unit 14 includes a projection mirror group front group 141, a scanning mirror 142 and a projection mirror group rear group 143, the scanning mirror 142 is located at a stop position of the projection unit 14, and the scanning mirror 142 is controlled by a driver to perform scanning swing; the imaging unit 15 includes a front group 151 of imaging lens groups, an aperture 152 of the imaging lens groups, and a rear group 153 of the imaging lens groups, and is configured to image the light reflected by the substrate 18 onto the detection module 16. The front group 141, the rear group 143, the front group 151 and the rear group 153 of the projection lens group are transmissive lens groups.
The substrate 18 is located right below the projection objective 17, after the light is reflected by the substrate 18, the light with the height and tilt information of the substrate 18 is imaged on the detection module 16 by the imaging unit 15, and the detection module 16 processes the information to obtain the accurate position of the substrate 18.
The reflective slit unit 13 is located at a stop position between the illumination module 12 and the scanning mirror 142 in the projection unit 14, and is also located at an object plane position between the illumination module 12 and the substrate 18. The included angle between the light ray and the reflective slit unit 13 is delta1The incident angle of the light ray to the substrate 18 is ω1The imaging magnification of the projection unit 14 is m1The reflective slit unit 13 and the substrate 18 satisfy the Scheimpflug condition, i.e.
tanω1＝m1tan(90°-δ1) Formula (3)
The included angle between the light ray and the detection surface of the detection module 16 is zeta1The imaging magnification of the imaging unit 15 is m2The detection plane of the substrate 18 and the detection module 16 satisfies the Scheimpflug condition, i.e.
tan(90°-ζ1)＝m2tanω1Formula (4)
When the substrate 18 is displaced from the focal plane of the projection objective 17 by a distance Δ Z1At time, i.e. defocus of the substrate 18, is Δ Z1In fig. 6, the solid line represents the best focal plane of the projection objective 17, the dashed line represents the actual position of the surface of the substrate 18, and the light reflected by the substrate 18 has a corresponding variation Δ L on the detection module 161Defocus Δ Z1And the variation quantity DeltaL1The following relationship is satisfied:
ΔL1＝2ΔZ1m2sinω1formula (5)
In the formula (5), ω1The angle of incidence, m, of the light to the substrate 182Is the optical magnification of the imaging unit 15. By defocus amount DeltaZ1And the variation quantity DeltaL1By measuring the amount of change DeltaL1The defocus amount DeltaZ of the substrate 18 can be obtained1。
Referring to fig. 7, which is a schematic structural diagram of a focusing and leveling device according to a second embodiment of the present invention, the focusing and leveling device includes a light source module 21, an illumination module 22, a reflection slit unit 23, a projection unit 24, an imaging unit 25, and a detection module 26, and is applicable to an ultraviolet band. The illumination module 22 includes an illumination mirror group 221 and a plane mirror 222, the projection unit 24 includes a projection mirror group front group 241, a scanning mirror 242 and a projection mirror group rear group 243, the scanning mirror 242 is located at a stop position of the projection unit 24, and the scanning mirror 242 is controlled by a driver to perform scanning swing; the imaging unit 25 includes a front group 251, a stop 252 and a rear group 253 of the imaging lens group for imaging the light reflected by the substrate 28 onto the detection module 26. The front group 241, the rear group 243, the front group 251 and the rear group 253 are all mirrors.
Light emitted by the light source module 21 is incident on the reflective slit unit 23 through the illumination module 22, the projection unit 24 projects the light reflected by the reflective slit unit 23 onto the substrate 28, the scanning mirror 242 performs scanning swing in a one-dimensional direction, the substrate 28 is located right below the projection objective 27, after the light is reflected by the substrate 28, the light with height and inclination information of the substrate 28 is imaged onto the detection module 26 through the imaging unit 25, and the detection module 26 processes the information to obtain an accurate position of the substrate 28.
The reflective slit unit 23 is located at a stop position between the illumination module 22 and the scanning mirror 242 in the projection unit 24, and is also located at an object plane position between the illumination module 22 and the substrate 28. The included angle between the light ray and the reflective slit unit 23 is delta2The incident angle of the light ray to the substrate 28 is ω2The imaging magnification of the projection unit 24 is m3The reflective slit unit 23 and the substrate 28 satisfy the Scheimpflug condition, i.e.
tanω2＝m3tan(90°-δ2) Formula (6)
The included angle between the light ray and the detection surface of the detection module 26 is zeta2The imaging magnification of the imaging unit 25 is m4Of substrate 28 and of detection module 26The detection surface satisfies the Scheimpflug condition, i.e.
tan(90°-ζ2)＝m4tanω2Formula (7)
When substrate 28 is offset from the focal plane of projection objective 27 by a distance Δ Z2At time, i.e. defocus of the substrate 28 is Δ Z2In fig. 7, the solid line represents the best focal plane of projection objective 27, the dashed line represents the actual position of the surface of substrate 28, and the light reflected by substrate 28 has a corresponding variation Δ L on detection module 262Defocus Δ Z2And the variation quantity DeltaL2The following relationship is satisfied:
ΔL2＝2ΔZ2m4sinω2formula (8)
In the formula (8), ω2The angle of incidence, m, of light rays incident on the substrate 284Is the optical magnification of the imaging unit 25. By defocus amount DeltaZ2And the variation quantity DeltaL2By measuring the amount of change DeltaL2The defocus amount DeltaZ of the substrate 28 can be obtained2。
In summary, in the focusing and leveling device, the lithographic apparatus and the focusing and leveling method provided in the embodiments of the present invention, the reflective slit unit is adopted, so that the dependence of the measurement mark on the slit substrate material is broken through, a larger selection space is provided for the substrate material, and no chromatic aberration exists when the wavelength band is greater than 0.3 μm, which is beneficial to greatly improving the energy utilization rate of the focusing and leveling device and improving the signal-to-noise ratio of detection.
The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (11)

1. A focusing and leveling device is used for detecting position information of a substrate and is characterized by comprising a light source module, an illumination module, a reflection slit unit, a projection unit, an imaging unit and a detection module, wherein light rays emitted by the light source module are incident on the reflection slit unit through the illumination module, are reflected by the reflection slit unit and then are projected onto the substrate through the projection unit, the light rays reflected by the substrate are imaged onto the detection module through the imaging unit, the detection module processes the received light rays to obtain position information of the substrate, and the reflection slit unit is located at diaphragm positions of the illumination module and the projection unit; the reflection slit unit is provided with a plurality of mark areas, the mark areas are plated with reflection films, and other areas except the mark areas are coated with coatings for reducing reflection.
2. The focusing and leveling device of claim 1 wherein the angle between the light incident on the reflective slit unit and the reflective slit unit is less than 90 degrees.
3. The focusing and leveling device according to claim 2, wherein the reflective slit unit and the substrate satisfy the following condition:
tanω＝matan(90°-δ)
wherein δ is an angle between the light and the reflective slit unit, ω is an incident angle of the light to the substrate, and maIs the imaging magnification of the projection unit.
4. The focusing and leveling device according to claim 1, wherein the light source module comprises a point light source, a coupling light path and an optical fiber, and light emitted from the point light source sequentially passes through the coupling light path and the optical fiber to reach the exit end of the optical fiber.
5. The focusing and leveling device according to claim 1, wherein the illumination module comprises an illumination lens group and a plane mirror, and the light is incident to the reflective slit unit after passing through the illumination lens group and the plane mirror.
6. The focusing and leveling device according to claim 1, wherein the projection unit comprises a scanning mirror and a plurality of projection mirror groups, and the scanning mirror is disposed at a stop position of the projection unit and driven by a driver to perform scanning swing so as to project the light reflected by the reflective slit unit onto the substrate.
7. The focusing and leveling device of claim 1 wherein the imaging unit comprises a plurality of imaging lens groups to image light reflected from the substrate onto the detection module.
8. The focusing and leveling device of claim 1 wherein the detection module is a photodetector.
9. The focusing and leveling device of claim 8 wherein the detection module and the substrate satisfy the following condition:
tan(90°-ζ)＝mbtanω
zeta is an included angle between the light ray and the detection module, omega is an incident angle of the light ray to the substrate, and mbIs the imaging magnification of the imaging unit.
10. A lithographic apparatus comprising a focusing and leveling device according to any one of claims 1 to 9 and a projection objective, said projection objective being located above a substrate.
11. A focus leveling method using the focus leveling apparatus according to any one of claims 1 to 9, comprising:
the light source module emits a light ray to the reflection slit unit through the illumination module;
the projection unit projects the light reflected by the reflection slit unit onto a substrate;
the imaging unit images the light reflected by the substrate onto a detection module, and the detection module processes the received light to obtain the position information of the substrate.
CN201811583111.4A 2018-12-24 2018-12-24 Focusing and leveling device, photoetching equipment and focusing and leveling method Active CN111352304B (en)

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US5748323A (en) * 1997-01-23 1998-05-05 Advanced Micro Devices Method and apparatus for wafer-focusing
JP3713354B2 (en) * 1997-03-21 2005-11-09 株式会社トプコン Position measuring device
JP4136067B2 (en) * 1997-05-02 2008-08-20 キヤノン株式会社 Detection apparatus and exposure apparatus using the same
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