TWI667723B - Cleanliness-inspection method of lithography apparatus and reflective mask - Google Patents

Abstract

A method for detecting the cleanliness of a lithography apparatus includes: placing a reflective reticle onto a reticle holder in an exposure chamber, and placing a wafer onto one of the wafer holders in the exposure chamber; via reflection The photomask performs an exposure process onto the wafer; the reflective mask is moved from the exposure chamber to an optical inspection machine; and the optical detector detects the contaminants on the reflective mask.

Description

Method for detecting the cleanliness of lithography equipment and reflective mask

The disclosure relates to a detection method and a reflective mask, and more particularly to a method for detecting the cleanliness of a lithography apparatus and a reflective mask.

Semiconductor devices have been used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic devices. The semiconductor device is fabricated substantially by sequentially depositing insulating or dielectric layers, conductive layers, and materials of the semiconductor layer to a wafer, and patterning a plurality of material layers using lithography techniques to form circuit components and components thereon. . Many integrated circuits are typically fabricated on a single wafer, and individual dies on the wafer are cut and separated along a cutting line between the integrated circuits. For example, individual dies are substantially packaged separately in a multi-wafer module or other type of package.

Due to the miniaturization of the size of the semiconductor process, ultra-ultraviolet light is used as a light source in the exposure process in the lithography apparatus to form a photoresist on the wafer to form a pattern suitable for a semiconductor process of less than 20 nm.

However, although lithographic apparatus that currently uses ultra-ultraviolet light as a light source in an exposure process meets its purpose of use, many other aspects have not been met. Therefore, there is a need to provide an improved solution for lithography equipment.

Some embodiments of the present disclosure provide a reflective reticle for use with To detect the cleanliness of a lithography apparatus, comprising: a substrate; a reflective structure disposed on the substrate; and a pattern layer disposed on the reflective structure, including a plurality of first detecting units. Each detection pattern includes a first detection unit. The first detecting units of the detecting patterns are arranged in an arrangement direction, and the area of the first detecting unit gradually becomes larger in the arrangement direction.

Some embodiments of the present disclosure provide a method for detecting the cleanliness of a lithography apparatus, including: placing a reflective reticle onto a reticle of an exposure cavity, and placing a wafer to a cavity in the exposure cavity On the round seat; performing an exposure process on the wafer via the reflective mask; moving the reflective mask from the exposure chamber to a first optical inspection machine; and detecting the reflective mask by the first optical inspection machine Contaminants on it.

1‧‧‧ lithography equipment

10‧‧‧Light source device

20‧‧‧ exposure cavity

30‧‧‧Lighting device

40‧‧‧Photomask device

41‧‧‧Photomask holder

50‧‧‧Optical projection device

51‧‧‧Mirror

60‧‧‧ Wafer Holder

70‧‧‧Photomask conveyor

80‧‧‧ wafer transfer device

A10‧‧‧ excitation cavity

A11‧‧‧Light channel

A20‧‧‧ target transmitter

A30‧‧‧ target recycler

A40‧‧‧Light concentrator

A50‧‧‧Laser transmitter

B1‧‧‧ optical inspection machine

B10‧‧‧ Carrying equipment

C1‧‧‧ first focus

C2‧‧‧ second focus

D1, D2‧‧‧ direction

E1‧‧‧

F1‧‧‧Photomask storage box

L1‧‧‧pulse laser

M1‧‧‧reflective mask

M10‧‧‧ substrate

M20‧‧‧reflective structure

M21‧‧‧ film pair

M30‧‧‧ protective layer

M40‧‧‧ pattern layer

M41‧‧‧ boron nitride layer

M42‧‧‧Boron Oxide Layer

M43‧‧‧ inspection pattern

M431, M431a, M431b, M431c, M431n‧‧‧ first detection unit

M432‧‧‧ first reference unit

M433, M433a, M433b, M433c, M433n‧‧‧ second detection unit

M434‧‧‧second reference unit

M44‧‧‧Main registration mark

M441‧‧‧First primary alignment unit

M442‧‧‧Second main alignment unit

M443‧‧‧ third main alignment unit

M45‧‧ ‧ registration mark

M451‧‧ ‧ alignment unit

M452‧‧‧ aligning ontology

M453‧‧‧Perforation

N1, N2, N3, N4, N5, N6‧‧‧ width

N11, N12, N13, N21, N22, N23‧‧‧ width

P1‧‧‧ length

Q1, Q2, Q3, Q4, Q5‧‧‧ spacing

R1, R2, R3, R4‧‧‧ path

D1, d2‧‧‧ distance

W1‧‧‧ wafer

W11‧‧‧ photoresist layer

Z1‧‧‧ first detection group

Z2‧‧‧Second detection group

1 is a schematic diagram of a lithography apparatus in accordance with some embodiments of the present disclosure.

2 is a flow chart of a method of detecting the cleanliness of a lithography apparatus in accordance with some embodiments of the present disclosure.

Figure 3 is a schematic illustration of an optical inspection machine in accordance with some embodiments of the present disclosure.

4 is a schematic illustration of a reflective reticle in accordance with some embodiments of the present disclosure.

Figure 5 is a top plan view of a reflective reticle in accordance with some embodiments of the present disclosure.

Figure 6 is a schematic illustration of a detection pattern in accordance with some embodiments of the present disclosure.

Figure 7 is a schematic illustration of a primary alignment mark in accordance with some embodiments of the present disclosure. Figure.

Fig. 8 is an enlarged view of a portion A according to Fig. 5.

Figure 9 is a schematic illustration of a detection pattern in accordance with some embodiments of the present disclosure.

The following description provides many different embodiments, or examples, for implementing the various features of the disclosure. The components and arrangements described in the following specific examples are only used to simplify the disclosure of the disclosed embodiments, which are merely by way of example, and are not intended to limit the disclosed embodiments. For example, the description of the structure of the first feature on or above a second feature includes direct contact between the first and second features, or another feature disposed between the first and second features such that The first and second features are not in direct contact.

In addition, the same reference numerals and/or characters are used in the present description in the different examples. The foregoing is merely for purposes of simplicity and clarity and is not intended to be

The vocabulary of the first and second words of this specification are for the purpose of clarity of explanation and are not intended to be construed as limiting. In addition, the first feature and the second feature are not limited to the same or different features.

Spatially related terms used herein, such as above or below, are used to simply describe one element or the relationship of one feature to another. In addition to the orientations described in the drawings, the devices are used or operated in different orientations. The shapes, dimensions, and thicknesses of the drawings may not be drawn to scale or simplified for the purpose of clarity of description, and are merely illustrative.

1 is a lithographic apparatus 1 according to some embodiments of the present disclosure. schematic diagram. The lithography apparatus 1 is configured to perform a lithography process on a wafer W1. The lithography process can include a photoresist coating process, a soft bake process, an exposure process, a development process, a hard bake process, and other suitable processes.

In this embodiment, the lithography apparatus 1 can be an exposure apparatus for performing an exposure process on a wafer W1. The lithography apparatus 1 can include a light source device 10, an exposure chamber 20, an illumination device 30, a reticle device 40, an optical projection device 50, and a wafer holder 60. The lithography apparatus 1 may include all of the above-described devices, but as long as the lithographic apparatus 1 is used for the purpose, it is not necessary to include all of the above-described devices.

The lithography apparatus 1 should not be limited to the apparatus described in the present disclosure. The lithography apparatus 1 may include other suitable devices, such as a coating device, a soft bake device, a developing device, and/or a hard bake device, to enable the lithography apparatus 1 to implement a complete lithography process to the wafer W1.

The light source device 10 is for generating light to the illumination device 30. The above light may be EUV light. In the present embodiment, the wavelength range of the above ultra-ultraviolet light can be defined as being in the range of 1 mm to 124 nm. In some embodiments, the wavelength of the light may be between 3 mm and 20 nm. Therefore, the light source device 10 can be an ultra-ultraviolet light source device. However, the light source device 10 should not be limited to generate ultra-ultraviolet rays. Light source device 10 can be used to emit any photon from any wavelength and intensity that is excited by the target E1.

The exposure chamber 20 is disposed on one side of the light source device 10. In some embodiments, illumination device 30, photomask device 40, optical projection device 50, and wafer holder 60 can be disposed within exposure chamber 20. However, since gas molecules absorb ultra-ultraviolet rays, a vacuum can be maintained inside the exposure chamber 20 to prevent ultra-violet loss.

The illumination device 30 is configured to guide the light (ultraviolet light) provided by the light source device 10 to a reflective mask (mask, photomask, or reticle) M1 disposed in the light source device 10. Illumination device 30 can include one or more optical elements, such as at least one lens, at least one mirror, and/or at least one refractor. The light emitted by the light source device 10 is refracted, reflected, and/or condensed by the illumination device 30 and guided to the reflective reticle M1 or the reticle device 40.

The mask device 40 is for holding the reflective mask M1. In some embodiments, the reticle device 40 can be used to move the reflective reticle M1 to direct light emitted by the illuminating device 30 to different regions of the reflective reticle M1. In some embodiments, the reticle device 40 can include a reticle holder 41 for holding the reflective reticle M1. The mask holder 41 can be an electrostatic chuck (e-chuck).

An imaging optics device (or projection optics box, POB) 50 is disposed between the reflective mask M1 and the wafer holder 60 for forming a pattern of the reflective mask M1 on the wafer W1. In some embodiments, optical projection device 50 can include a plurality of optical elements, such as at least one lens, at least one mirror, and/or at least one refractive mirror. The light emitted by the reflective mask M1 carries an image defined by the pattern on the reflective mask M1, and is refracted, reflected, and/or condensed by the optical projection device 50 and guided to the wafer W1 or the wafer holder 60. .

In the present embodiment, the optical projection device 50 includes a plurality of mirrors 51 for reflecting light (or ultra-ultraviolet rays). The light emitted by the reflective mask M1 is reflected and concentrated by the optical projection device 50 and guided to the wafer W1 or the wafer holder 60.

The wafer holder 60 is disposed below the reflective mask M1. In this implementation In the example, the wafer holder 60 is disposed below the optical projection device 50. The wafer holder 60 is used to hold the wafer W1. The wafer holder 60 can be an electrostatic chuck (e-chuck).

Wafer W1 can be made of tantalum or other semiconductor materials. In some embodiments, the wafer W1 may be made of a compound semiconductor material such as silicon carbide (SiC), gallium arsenic (GaAs), indium arsenide (InAs). Or indium phosphide (InP). In some embodiments, the wafer W1 may be made of an alloy semiconductor such as silicon germanium (SiGe), silicon germanium carbide (SiGeC), gallium arsenic phosphide (gallium arsenic phosphide). , GaAsP), or gallium indium phosphide (GaInP). In some embodiments, the wafer W1 can be a silicon-on-insulator (SOI) or a germanium-on-insulator (GOI) substrate.

Further, the wafer W1 may have various device elements. For example, device components formed on wafer W1 can include transistors, diodes, and/or other suitable components. A variety of different processes can be used to form the device components described above. For example, deposition processes, etching processes, implant processes, lithography processes, and/or other suitable processes.

In some embodiments, wafer W1 is coated with a photoresist layer W11 that can chemically react to light (or ultraviolet light). When the patterned light emitted through the optical projection device 50 is irradiated to the photoresist layer W11, the photoresist layer W11 can be patterned.

The light source device 10 can use a pulsed laser to excite plasma (pulse laser Produced plasma, pulse LPP) mechanism to make the standard E1 produce plasma, and the plasma emits ultra-ultraviolet light. The light source device 10 can include an excitation cavity A10, a target emitter A20, a target recycler A30, a light concentrator A40, and a laser emitter A50.

The light source device 10 may include all of the above-described devices, but as long as the purpose of the light source device 10 is achieved, it is not necessary to include all of the above devices. Light source device 10 should not be limited to the devices described in this disclosure, and may include other suitable components.

The excitation chamber A10 may be located on one side of the exposure chamber 20. The excitation cavity A10 can be connected to the exposure chamber 20 via a light tunnel A11. Since the gas molecules absorb ultra-ultraviolet rays, a vacuum can be maintained inside the excitation chamber A10 to prevent ultra-violet loss.

The target emitter A20 is disposed above the excitation chamber A10 and can be used to emit a plurality of targets E1. The target E1 can be illuminated by the pulsed laser L1 emitted by the laser emitter A50 in the excitation chamber A10 and excites the ultra-ultraviolet light. The target E1 can be liquid or solid. In this embodiment, the target E1 may be in a liquid state and may be a tin droplet. In some embodiments, the material of the target E1 may be tin including a liquid material, for example, a eutectic alloy including tin, lithium, and xenon (Xe).

The target recycler A30 is disposed on the excitation chamber A10 for recovering the target E1 emitted by the target emitter A20 but not irradiated by the pulsed laser L1. In this embodiment, the target collector A30 and the target emitter A20 may be on opposite sides of the excitation chamber A10.

Light collector A40 for reflecting ultra-ultraviolet light The line and the ultra-ultraviolet light are transmitted to the illumination device 30 in the exposure chamber 20 via the light tunnel A11. In the present embodiment, the light concentrator A40 can be, for example, an elliptical lens having a first focus C1 located within the excitation cavity A10 and a second focus C2 within the exposure cavity 20.

When the target E1 excites the ultra-ultraviolet light after the first focus C1 is irradiated by the pulsed laser L1 emitted by the laser emitter A50, the ultra-ultraviolet light can be reflected to the second focus C2 via the light concentrator A40. Since the second focus C2 can be located in the illumination device 30 of the exposure chamber 20, the ultra-ultraviolet light can be concentrated on the illumination device 30 by the light concentrator A40 in this embodiment.

In some embodiments, the second focus C2 may be located in the excitation cavity A10 or the light channel A11, and the ultra-ultraviolet light in the second focus C2 may be irradiated to the reflective mask M1 via the illumination device 30.

It should be noted that the shape or structure of the light concentrator A40 is not limited as long as the ultraviolet light excited by the target E1 can be concentrated in an area. For example, the light concentrator A40 can be parabolic.

The laser emitter A50 is disposed on the excitation chamber A10. The laser emitter A50 can be used to generate a pulse laser L1 that passes through the light concentrator A40 and illuminates the first focus C1. When the pulsed laser L1 is irradiated to the target E1, the target E1 can be excited to become a plasma, and the plasma is caused to generate ultra-ultraviolet rays. In some embodiments, the laser emitter A50 can have two. The light source device 10 can use a dual-pulse laser produced plasma (dual-pulse LPP).

2 is a flow chart of a method of detecting the cleanliness of lithography apparatus 1 in accordance with some embodiments of the present disclosure. In step S101, one of the lithography apparatuses 1 The mask transfer device 70 places the reflective mask M1 on the mask holder 41 in the exposure chamber 20. The wafer W1 is placed on the wafer holder 60 in the exposure chamber 20 by a wafer transfer device 80 of the lithography apparatus 1.

In step S103, an exposure process is performed on the wafer W1 via the reflective mask M1. In the exposure process, the laser emitter A50 generates a pulsed laser L1 to illuminate the target E1 and produces an ultra-ultraviolet light. Ultraviolet rays are reflected to the illumination device 30 via the light concentrator A40, and are irradiated to the reflective reticle M1 via the illumination device 30. Ultraviolet light is reflected by the reflective mask M1 to form a patterned ultra-ultraviolet light. The patterned ultra-violet light is irradiated to the photoresist layer W11 on the wafer W1 via the optical projection device 50.

During the exposure process, if there is dust or the like in the exposure chamber 20, it may fall and adhere to the reflective mask M1. If the surface of the reflective mask M1 is contaminated with contaminants, it will cause a photoresist layer W11, which in turn affects the yield of the wafer W1.

Figure 3 is a schematic illustration of an optical inspection machine B1 in accordance with some embodiments of the present disclosure. The optical inspection machine B1 can be a lightning detection optical inspection machine or an electron microscope inspection machine. In step S105, the mask transfer device 70 removes the reflective mask M1 from the exposure chamber 20 and puts it into a mask storage case F1. The reticle storage box F1 equipped with the reflective reticle M1 can be moved to the carrier 埠B10 of the optical inspection machine B1 via a transport device (not shown).

In step S107, the optical detecting machine B1 moves the reflective mask M1 on the carrier B10 to the inside of the optical detecting machine B1 for detection. The optical inspection machine B1 detects the number, distribution, and size of contaminants on the reflective mask M1.

In step S109, when the optical detecting machine B1 detects that the amount of the contaminant on the reflective mask M1 exceeds a predetermined value, a mask cleaning process can be performed. In the mask cleaning process, the reflective mask M1 can be used to remove contaminants from the reflective mask M1 via a mask cleaning machine (not shown).

In some embodiments, the reflective reticle M1 is a product reticle, so that a pattern of the circuit layout corresponding to the product can be formed on the wafer W1 by the product reticle. By the method for detecting the cleanliness of the lithography apparatus 1 of the present disclosure, it is possible to effectively prevent the use of the reflective mask M1 which causes exposure defects in the exposure process of the wafer W1 of the product, thereby improving the yield of the wafer W1. .

In addition, when the optical detecting machine B1 detects that the amount of the contaminant on the reflective mask M1 exceeds a predetermined value, it may represent that the cleanliness in the exposure chamber 20 is too low, and a machine cleaning procedure may be performed. At this time, the operation of the lithography apparatus 1 can be stopped, and the operation of removing the contaminants for the exposure chamber 20 can be performed, for example, the components inside the exposure chamber 20 are wiped with a clean liquid to remove the contamination attached to the components inside the exposure chamber 20. Things.

In some embodiments, the optical inspection machine B1 can be an electron microscope, which can be used to capture the surface of the reflective mask M1, and analyze the image of the surface of the reflective mask M1 and the number and location of contaminants on the image. . In some embodiments, the optical inspection machine B1 can be a laser detection machine that can be used to emit a laser to scan the surface of the reflective reticle M1 and analyze the laser reflection through the surface of the reflective reticle M1. The number and location of contaminants on the surface of the reflective mask M1.

Accordingly, in the present disclosure, by detecting the contaminants on the reflective mask M1, the exposure chamber 20 can be immediately cleaned by the machine to avoid the reflective mask. M1 is defective in the wafer W1 due to the contamination of the contaminants in the exposure chamber 20.

In some embodiments, after the wafer W1 is subjected to the complete lithography process, the wafer W1 can be transported to the optical inspection machine B1 to detect the developed photoresist layer W11. The optical inspection machine B1 can further compare the pattern of the photoresist layer W11 and the detection result of the reflective mask M1 to further analyze the number, distribution, and size of the contaminants to more accurately determine whether to perform a mask cleaning. Program and / or a machine cleaning program. In addition, the influence of the contaminants on the reflective mask M1 on the pattern of the photoresist layer W11 of the wafer W1 can be analyzed, thereby serving as a basis for improving the lithography apparatus 1.

In some embodiments, the wafer W1 and the reflective mask M1 are detected using the same optical inspection station B1. In some embodiments, the wafer W1 and the reflective mask M1 are separately detected using different optical inspection stations.

FIG. 4 is a schematic illustration of a reflective reticle M1 in accordance with some embodiments of the present disclosure. In some embodiments, the reflective reticle M1 is a detection reticle. The detection reticle can be used to detect the cleanliness within the exposure chamber 20. The reflective mask M1 has a pattern layer M40 designed for the detection method of the cleanliness of the lithography apparatus 1, whereby the number, distribution, and size of the contaminants on the reflective mask M1 can be more accurately analyzed. In turn, it is possible to more accurately determine whether to perform a mask cleaning procedure and/or a machine cleaning procedure.

The reflective reticle M1 may include a substrate M10, a reflective structure M20, a protective layer M30, and a pattern layer M40. The material of the substrate M10 may include a low thermal expansion metal (LTEM). The aforementioned low thermal expansion material may comprise doped titanium oxide (TiO ₂₎ of silicon oxide (SiO _2), and / or other low thermal expansion material. The substrate M10 formed of a low thermal expansion material minimizes image distortion problems caused by the heating mask. In some embodiments, the materials included in some embodiments have a low defect level and a smooth surface.

The reflective structure M20 is disposed on the substrate M10 for reflecting light or ultra-ultraviolet light. In some embodiments, the reflective structure M20 is a multi-layer structure. The reflective structure M20 may include a film pair M21, such as a molybdenum-silicon (Mo/Si) film pair, wherein in each film pair M21, one layer of molybdenum is disposed on or under another layer of germanium. . In some embodiments, the film pair M21 may be a molybdenum-beryllium (Mo/Be) film pair or other suitable material capable of highly reflecting ultraviolet light.

In some embodiments, the number of the film pairs M21 in the reflective structure M20 is between 20 and 80, but is not limited thereto. In some embodiments, the reflective structure M20 comprises 40 film pairs M21.

The protective layer M30 is disposed above the reflective structure M20. In some embodiments, the protective layer M30 disposed over the reflective structure M20 serves to prevent oxidation of the reflective structure M20. In some embodiments, the protective layer M30 can include a single film or a multilayer film to have additional functionality. In some embodiments, the protective layer M30 can serve as an etch stop layer in the patterning or repair process of the pattern layer M40.

In some embodiments, the material of the protective layer M30 comprises ruthenium (Ru), a ruthenium compound such as ruthenium boride (RuB) or ruthenium (RuSi), chromium (Cr), chromium oxide (CrO), or chromium nitride (CrN). ).

The pattern layer M40 is disposed above the protective layer M30. As shown in FIG. 4, the pattern layer M40 covers the partial reflection structure M20. Pattern layer M40 absorbs illumination The ultra-ultraviolet light thereon, and the reflective structure M20 not covered by the pattern layer M40 reflects ultra-ultraviolet rays. Therefore, the ultra-ultraviolet light reflected by the reflective mask M1 forms a patterned ultra-ultraviolet light.

The pattern layer M40 may include a plurality of film layers, and the material of each film layer may include chromium, chromium oxide, chromium nitride, titanium, titanium oxide, titanium nitride, tantalum, hafnium oxide, tantalum nitride, niobium oxynitride, nitrogen. Boron bismuth, boron oxynitride, boron oxynitride, aluminum, aluminum-copper, aluminum oxide, silver, silver oxide, palladium, rhodium, molybdenum, other suitable materials or combinations thereof. As shown in FIG. 4, the pattern layer M40 includes a boron nitride tantalum (TaBN) layer M41 over the protective layer M30 and a boron oxide tantalum (TaBO) layer M42 over the boron nitride layer M41. In some embodiments, the boron nitride layer M41 has a thickness of about 50 nm to 80 nm, such as about 68 nm. In some embodiments, the boron oxynitride layer M42 has a thickness of about 1 nm to 10 nm, such as about 2 nm.

Figure 5 is a top plan view of a reflective reticle M1 in accordance with some embodiments of the present disclosure. The pattern layer M40 includes a plurality of detection patterns M43, a main alignment mark M44, and a plurality of sub-alignment marks M45. The detection patterns M43 may be arranged in an array in the pattern layer M40. The number of detection patterns M43 depends on the size of the reflective mask M1 and is not limited. In some embodiments, the number of detection patterns M43 may be from 16 to 900. The detection pattern M43 may be rectangular, but is not limited thereto.

The width N1 of the detection pattern M43 may be between about 3 mm and 7 mm. In some embodiments, the detection pattern M43 may have a width N1 of about 5 mm. The length P1 of the detection pattern M43 may be between about 5 mm and 9 mm. In some embodiments, the length P1 of the detection pattern M43 can be about 7 mm. The above width N1 can be measured in the arrangement direction D1. The above length P1 can enter along the arrangement direction D2 Line measurement. The arrangement direction D1 may be perpendicular to the arrangement direction D2.

The minimum pitch Q1 of the two adjacent detection patterns M43 is between about 0.5 mm and 3 mm. In some embodiments, the minimum spacing Q1 of the two adjacent detection patterns M43 is about 1 mm. The distance between the detection pattern M43 and the edge of the reflective mask M1 is between about 0.5 mm and 3 mm. In some embodiments, the minimum spacing Q2 of the two adjacent detection patterns M43 is about 1 mm or 1.5 mm.

In some embodiments, the detection patterns M43 arranged in the arrangement direction D1 may be the same. The detection patterns M43 arranged in the arrangement direction D2 may be different. For example, the detection pattern M43 of the third row in FIG. 5 may be a standard detection pattern, and the detection pattern M43 of the fourth row in FIG. 5 may be a product detection pattern. Standard inspection patterns and product inspection patterns present one or more circuit layouts.

In some embodiments, the detection patterns M43 are arranged in an array, and the main alignment mark M44 is adjacent to a corner of the array formed by the detection pattern M43. In some embodiments, the reflective reticle M1 is a quadrilateral. The main registration mark M44 is adjacent to a corner of the reflective mask M1. Further, the main alignment mark M44 may be adjacent to a corner of the reflective mask M1 and the primary alignment mark M45. In some embodiments, the detection pattern M43 can be a quadrilateral. The sub-alignment mark M45 is adjacent to a corner located in each of the detection patterns M43.

Figure 6 is a schematic illustration of a detection pattern M43 in accordance with some embodiments of the present disclosure. The detection pattern M43 may include a plurality of first detecting units M431 (M431a, M431b, M431c...M431n), a plurality of first reference units M432, a plurality of second detecting units M433a (M433b, M433c...M433n), and a plurality of second references Unit M434. In some embodiments, a first detecting unit M431 and a plurality of first reference units M432 form a first detecting group Z1, and the above The plurality of first reference units M432 are arranged around one of the first detecting units M431. A second detecting unit M433 and a plurality of second reference units M434 form a second detecting group Z2, and the plurality of second reference units M434 are arranged around a second detecting unit M433.

For example, each of the first detecting units M431a, M431b, M431c... or M431n in FIG. 6 forms a first detecting group Z1 with the four first reference units M432. The first detection group Z1 may be a rectangle, and the four first reference units M432 are respectively located at the corners of the first detection group Z1. Each of the second detecting units M433a, M433b, M433c... or M433n in FIG. 6 also forms a second detecting group Z2 with the four second reference units M434. The second detection group Z2 may be a rectangle, and the four second reference units M434 are respectively located at the corners of the second detection group Z2. It should be noted that the number of the first reference units M432 in each of the first detection groups Z1 and the number of the second reference units M434 in each of the second detection groups Z2 may be adjusted as needed.

The plurality of first detection groups Z1 are arranged in the arrangement direction D1. The plurality of second detection groups Z2 are arranged along the arrangement direction D1. In some embodiments, the first detection group Z1 and the second detection group Z2 are staggered in the arrangement direction D2. For example, in the arrangement direction D2, the second detection group Z2 of the second row is located between the first detection group Z1 of the first row and the first detection group Z1 of the third row, and the third row The first detection group Z1 is located between the second detection group Z2 of the second row and the second detection group Z2 of the fourth row, and so on.

In the first detection group Z1 of each column, the first detection units M431a, M431b, M431c...M431n are arranged along the arrangement direction D1, and the areas of the first detection units M431a, M431b, M431c...M431n are arranged along the arrangement direction. D1 gradually becomes larger. The area of each of the first reference units M432 may be the same. In some embodiments, the center of each first reference unit M432 is equal to the shortest distance d1 of the center of one of the first detecting units M431a, M431b, M431c...M431n.

In some embodiments, the width N12 of the first detecting unit M431b is greater than the width N11 of the first detecting unit M431a. The difference between the width N12 of the first detecting unit M431b and the width N11 of the first detecting unit M431a is 0.5 nm. The width N13 of the first detecting unit M431c is larger than the width N12 of the first detecting unit M431b. The difference between the width N13 of the first detecting unit M431c and the width N12 of the first detecting unit M431b is 0.5 nm. In other words, the width of the first detecting unit M431 is gradually increased by a predetermined value in the arrangement direction D1. In some embodiments, the predetermined value may be between 0.2 nm and 1.0 nm.

In the second detection group Z2 of each column, the second detection units M433a, M433b, M433c...M433n are arranged along the arrangement direction D1, and the areas of the second detection units M433a, M433b, M433c...M433n are gradually reduced along the arrangement direction D1. . The area of each second reference unit M434 may be the same. In some embodiments, the center of each second reference unit M434 is equal to the shortest distance d2 of the center of one of the second detection units M433b, M433c...M433n.

In some embodiments, the width N2 of the second detecting unit M433b is smaller than the width N21 of the second detecting unit M433a. The difference between the width N22 of the second detecting unit M433b and the width N21 of the second detecting unit M433a is 0.5 nm. The width N33 of the second detecting unit M433c is larger than the width N32 of the second detecting unit M433b. The difference between the width N33 of the second detecting unit M433c and the width N32 of the second detecting unit M433b is 0.5 nm. In other words, the second test list The width of the element M433 is gradually reduced by a predetermined value along the arrangement direction D1. In some embodiments, the predetermined value may be between 0.2 nm and 1.0 nm.

With the design of the detection pattern M43 of the present disclosure, when the plurality of contaminants are dropped onto the different detection patterns M43, the optical inspection machine B1 can accurately analyze the pollutants after analyzing the surface of the reflective mask M1. They are dropped onto those detection patterns M43, respectively, and the number, position and area of the contaminants covering the detection pattern M43 can be calculated. Therefore, the optical inspection machine B1 can more accurately analyze the number, distribution, and size of the contaminants to more accurately determine whether or not to perform a mask cleaning process and/or a machine cleaning program.

Figure 7 is a schematic illustration of a primary alignment mark M44 in accordance with some embodiments of the present disclosure. The maximum width N2 of the main registration mark M44 may be between about 150 um and 250 um. In some embodiments, the maximum width N2 of the primary alignment mark M44 can be approximately 200 um. The above width N2 is measured along the extending direction D1.

The main registration mark M44 includes a plurality of first main alignment units M441, a plurality of second main alignment units M442, and a plurality of third main alignment units M443. In some embodiments, the first primary alignment unit M441, the second primary alignment unit M442, and the third primary alignment unit M443 may be polygonal or quadrilateral, but are not limited thereto. In some embodiments, the first primary alignment unit M441, the second primary alignment unit M442, and the third primary alignment unit M443 may be rectangular. The area of the first main aligning unit M441 is larger than the area of the second main aligning unit M442. The area of the second main aligning unit M442 is larger than the area of the third main aligning unit M443.

The maximum width N3 of the first main alignment unit M441 may be between about 40 um to 140 um. In some embodiments, the maximum width N3 of the first primary alignment unit M441 may be approximately 90 um. Two adjacent first main alignment units M441 The minimum spacing Q3 between may be between about 10 um and 30 um. In some embodiments, the minimum spacing Q3 between two adjacent first primary alignment units M441 may be approximately 20 um. The width N3 and the pitch Q3 are measured along the extending direction D1.

The maximum width N4 of the second main alignment unit M442 may be between about 13 um to 23 um. In some embodiments, the maximum width N4 of the second primary alignment unit M442 can be approximately 18 um. The minimum spacing Q4 of the two adjacent second primary aligning units M442 may be between about 2 um and 6 um. In some embodiments, the minimum spacing Q4 between two adjacent second primary alignment units M442 may be approximately 4 um. The width N4 and the pitch Q4 are measured along the extending direction D1.

The maximum width N5 of the third main alignment unit M443 may be between about 1 um to 3 um. In some embodiments, the maximum width N5 of the third primary alignment unit M443 may be approximately 2 um. The minimum spacing Q4 of the two adjacent third primary aligning units M443 may be between about 0.5 um to 1.5 um. In some embodiments, the minimum spacing Q4 between two adjacent third primary alignment units M443 may be approximately 1 um. The width N5 and the pitch Q5 are measured along the extending direction D1.

In some embodiments, the number of first primary alignment units M441 can be three. The center of the first main alignment unit M441 is located at the three top ends of a rectangular path R1, and the second main alignment unit M442 is adjacent to the other top end of the rectangular path R1. The area of any of the first primary alignment units M441 is greater than the total area of the second primary alignment unit M442.

In some embodiments, the number of second primary alignment units M442 can be three. The center of the second main aligning unit M442 is located at the three top ends of a rectangular path R2, and the third main aligning unit M443 is adjacent to the other top end of the rectangular path R2. The area of any one of the second primary alignment units M442 is greater than the third primary alignment table Yuan M443.

In some embodiments, the number of third primary alignment units M443 may be three, and the center of the third primary alignment unit M443 is located at three top ends of a rectangular path R3. The rectangular path R2 described above surrounds the rectangular path R3, and the rectangular path R1 surrounds the second rectangular path R2. In some embodiments, the rectangular paths R1, R2, R3 described above may be square paths.

By the design of the main alignment mark M44 of the above disclosure, the influence of the contaminant mark pattern formed on the photoresist layer W11 of the wafer W1 when the contaminant is covered by the main alignment mark M44 can be more accurately analyzed. .

Fig. 8 is an enlarged view of a portion A according to Fig. 5. Each of the alignment marks M45 is adjacent to one detection pattern M43. The secondary alignment mark M45 may include a plurality of secondary alignment units M451. The shape of the sub-alignment unit M451 may be a polygon or a quadrangle, but is not limited thereto. The shape of the secondary alignment unit M451 may be a rectangle or a square. In some embodiments, the number of secondary alignment units M451 can be three. The center of the secondary alignment unit M451 is located at the three top ends of a rectangular path R4. One corner of the detection pattern M43 is located at the other top end of the rectangular path R4. In some embodiments, the rectangular path R4 described above can be a square path.

Figure 9 is a schematic illustration of a detection pattern M43 in accordance with some embodiments of the present disclosure. Each alignment unit M451 includes a pair of bit bodies M452 and a plurality of alignment holes M453. The registration hole M453 is formed in the alignment body M452. In some embodiments, the alignment holes M453 are arranged in an array. The number of alignment holes is between about 100 and 10,000, but is not limited thereto. The width N6 of the alignment holes M453 may be between about 50 nm and 200 nm. In some embodiments, the width N6 of the alignment holes M453 can be about 100 nm. The above width N6 is along the extending direction D1 Make measurements.

The design of the sub-alignment mark M45 according to the above disclosure can more accurately analyze the influence on the alignment mark pattern formed by the photoresist layer W11 of the wafer W1 when the contaminant covers the sub-alignment mark M45. In addition, since each of the alignment marks M45 corresponds to one detection pattern M43, the optical inspection machine B1 can also be configured to analyze the number, distribution, and size of the contaminants to more accurately determine whether or not to perform a mask cleaning process and / or a machine cleaning program.

In some embodiments, the first main aligning unit M441, the second main aligning unit M442, and the third main aligning unit M443 may form a plurality of aligning holes according to the design of the secondary aligning unit M451.

In summary, the lithographic apparatus of the present disclosure utilizes the amount of contaminants on the reflective reticle to determine whether to perform a reticle cleaning procedure on the reflective reticle and/or a machine cleaning procedure for the lithographic apparatus. Can reduce wafer defects and increase wafer yield.

Some embodiments of the present disclosure provide a reflective reticle for detecting the cleanliness of a lithography apparatus, including: a substrate; a reflective structure disposed on the substrate; and a patterned layer disposed on the reflective structure, A plurality of first detecting units are included. Each detection pattern includes a first detection unit. The first detecting units of the detecting patterns are arranged in an arrangement direction, and the area of the first detecting unit gradually becomes larger in the arrangement direction.

In some embodiments, the pattern layer further includes a plurality of first reference cells arranged around the first detecting unit, wherein a center of each of the first reference cells has a shortest distance from a center of one of the first detecting units .

In some embodiments, each detection pattern further includes a second inspection The measuring unit, wherein the second detecting units of the detecting patterns are arranged in the arrangement direction, and the area of the second detecting unit gradually becomes smaller in the arrangement direction.

In some embodiments, each of the detection patterns further includes a plurality of second reference units arranged around the second detection unit, wherein the center of each of the second reference units and the center of one of the second detection units are the shortest The distance is equal.

In some embodiments, the first detecting unit and the second detecting unit are staggered in a direction perpendicular to the arrangement direction.

In some embodiments, the pattern layer further includes a main alignment mark adjacent to a corner of one of the arrays formed by the detection pattern, and the main alignment mark includes a plurality of first main alignment units and a plurality of second main pairs a bit unit, wherein an area of any one of the first main aligning units is greater than a total area of the second main aligning unit, wherein the number of the first main aligning units may be three, and the center of the first main aligning unit is located The three top ends of a rectangular path, and the second main alignment unit is adjacent to the other top end of the rectangular path.

In some embodiments, the pattern layer further includes a plurality of sub-alignment marks, wherein each of the alignment marks is adjacent to a corner of one of the detection patterns, and each of the alignment marks includes at least three sub-alignment units, The centers of the at least three sub-alignment units are respectively located at three top ends of a rectangular path, wherein one of the detection patterns is located at the other top end of the rectangular path, and each alignment unit includes a plurality of alignments arranged in an array manner Holes, and the number of alignment holes is greater than 100.

Some embodiments of the present disclosure provide a method for detecting the cleanliness of a lithography apparatus, including: placing a reflective reticle onto a reticle of an exposure cavity, and placing a wafer to a cavity in the exposure cavity On the round seat; performing an exposure process on the wafer via the reflective mask; moving the reflective mask from the exposure chamber to a a first optical inspection machine; and detecting a contaminant on the reflective reticle by the first optical inspection machine.

In some embodiments, the method of detecting the cleanliness of the lithography apparatus includes performing a reticle cleaning procedure and/or a machine cleaning procedure when the amount of contaminants on the reflective reticle exceeds a predetermined value.

In some embodiments, the method of detecting the cleanliness of the lithography apparatus comprises: moving the wafer onto a second optical inspection machine; and detecting the exposure pattern on the wafer via the second optical inspection machine.

The present disclosure is disclosed in the above embodiments, but is not intended to limit the scope of the disclosure. Any one skilled in the art can make some changes without departing from the spirit and scope of the disclosure. With retouching. Therefore, the above embodiments are not intended to limit the scope of the disclosure, and the scope of the disclosure is defined by the scope of the appended claims.

Claims (10)

A reflective reticle for detecting the cleanliness of a lithography apparatus, comprising: a substrate; a reflective structure disposed on the substrate; and a pattern layer disposed on the reflective structure and including a plurality of detection patterns Each of the detection patterns includes a first detecting unit; wherein the first detecting units of the detecting patterns are arranged along an arrangement direction, and an area of the first detecting units gradually becomes larger along the arrangement direction. The reflective reticle of claim 1, wherein each of the detection patterns further comprises a plurality of first reference units arranged around the first detection unit, wherein each of the first reference units The center is equal to the shortest distance of the center of one of the first detection units. The reflective reticle of claim 2, wherein each of the detection patterns further comprises a second detecting unit, wherein the second detecting units of the detecting patterns are arranged along the arrangement direction, and the The area of the second detecting unit gradually becomes smaller along the arrangement direction. The reflective reticle of claim 3, wherein each of the detection patterns further comprises a plurality of second reference units arranged around the second detection unit, wherein each of the second reference units The center is equal to the shortest distance of the center of one of the second detecting units. The reflective reticle of claim 4, wherein the first detecting unit and the second detecting unit are staggered in a direction perpendicular to the arranging direction. The reflective reticle of claim 1, wherein the pattern layer is further Included as a primary alignment mark adjacent to a corner of one of the arrays formed by the detection patterns, and the primary alignment mark includes a plurality of first primary alignment units and a plurality of second primary alignment units, wherein The area of any one of the first primary aligning units is greater than the total area of the second primary aligning units, wherein the number of the first primary aligning units is three, and the centers of the first primary aligning units Located at three top ends of a rectangular path, and the second primary alignment unit is adjacent to the other top end of the rectangular path. The reflective reticle of claim 1, wherein the pattern layer further comprises a plurality of sub-alignment marks, wherein each of the sub-alignment marks is adjacent to a corner of one of the detection patterns, And each of the secondary alignment marks includes at least three secondary alignment units, the centers of the at least three secondary alignment units are respectively located at three top ends of a rectangular path, wherein one of the detection patterns is located in the rectangle At the other top of the path, each of the equal-order alignment units includes a plurality of alignment holes arranged in an array, and the number of the alignment holes is greater than 100. A method for detecting the cleanliness of a lithography apparatus, comprising: placing a reflective mask as described in claim 1 to a mask holder in an exposure chamber, and placing a wafer into the exposure chamber Performing an exposure process on the wafer via the reflective mask; moving the reflective mask from the exposure chamber to a first optical inspection machine; and by using the first optical The inspection machine detects the contaminants on the reflective reticle. The detection method of the cleanliness of the lithography apparatus as described in claim 8 The method includes: performing a reticle cleaning procedure and/or a machine cleaning procedure when the amount of the contaminant on the reflective reticle exceeds a predetermined value. The method for detecting the cleanliness of a lithography apparatus according to claim 8, comprising: moving the wafer to a second optical inspection machine; and detecting the wafer via the second optical inspection machine Exposure graphics on.