阅读说明：本技术 光罩处理方法及微影装置 (Mask processing method and lithographic apparatus ) 是由 廖主玮 廖啟宏 于 2019-03-12 设计创作，主要内容包括：本揭示揭露一种光罩处理方法及微影装置。根据本揭示的一些实施方式,一种光罩处理方法包含判断颗粒是否在光罩的接触表面上。若颗粒在接触表面,则光罩被清洁以由光罩的接触表面移除颗粒。在清洁光罩之后,光罩被设置于吸盘上,其中光罩的接触表面在光罩设置于吸盘上时接触吸盘。微影制程利用设置于吸盘上的光罩被执行。(A mask processing method and a lithographic apparatus are disclosed. According to some embodiments of the present disclosure, a method of processing a reticle includes determining whether particles are on a contact surface of the reticle. If particles are on the contact surface, the mask is cleaned to remove the particles from the contact surface of the mask. After cleaning the reticle, the reticle is disposed on the chuck, wherein the contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck. The photolithography process is performed using a mask disposed on a chuck.)

1. A method for processing a mask, comprising:

determining whether a particle is on a contact surface of a mask;

cleaning the mask to remove the particles from the contact surface of the mask if the particles are on the contact surface;

disposing the reticle on a chuck after cleaning the reticle, wherein the contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck; and

a photolithography process is performed using the mask disposed on the chuck.

2. The method of claim 1, wherein the mask has a patterned region and an unpatterned region, and the contact surface of the mask is in the unpatterned region.

3. The method of claim 1, wherein the reticle has a plurality of unpatterned regions and a patterned region located between the unpatterned regions, and the contact surface of the reticle is within the unpatterned regions.

4. A method for processing a mask, comprising:

determining whether a particle is on a contact surface of a mask;

determining a height of the particle if the particle is on the contact surface;

determining whether the height of the particle is less than a predetermined height;

if the height of the particle is less than the predetermined height, disposing the reticle on a chuck, wherein the contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck; and

a photolithography process is performed using the mask disposed on the chuck.

5. The method of claim 4, further comprising:

if the height of the particles is greater than the predetermined height, the mask is cleaned.

6. The method of claim 4, wherein the step of determining the height of the particles comprises:

capturing a plurality of two-dimensional images of the particle at different heights; and

determining the height of the particle using the plurality of two-dimensional images of the particle.

7. The method of claim 4, further comprising:

a holder contacting opposing sidewalls of the mask is used to hold the mask when determining whether the particles are on the contact surface of the mask.

8. The method of claim 4, further comprising:

the reticle is held by a holder that contacts opposing sidewalls of the reticle while the height of the particles is measured.

9. A lithographic apparatus, comprising:

a first compartment;

a detection system within the first compartment and configured to determine whether a particle is on a mask;

a measurement system within the first compartment and configured to determine a height of the particle while the particle is on the mask;

a second compartment, wherein the first compartment and the second compartment share a sidewall, and the sidewall has a channel communicating the first compartment and the second compartment;

a suction cup within the second compartment; and

a transfer mechanism configured to transfer the mask between the chuck, the inspection system and the measurement system.

10. The lithographic apparatus of claim 9, wherein the inspection system is configured to inspect an unpatterned region of the mask.

Technical Field

The present disclosure relates to a mask processing method and a lithographic apparatus.

Background

In the semiconductor Integrated Circuit (IC) industry, technological advances in IC materials and design have resulted in one generation of yet another integrated circuit, each of which is smaller and more complex than the previous generation. In the development of integrated circuits, the functional density (i.e., the number of interconnect elements per chip area) generally increases, while the geometry (i.e., the smallest component (or line) that can be created using a manufacturing process) decreases. Such a scaled down flow generally provides benefits by increasing production efficiency and reducing associated costs. This scaling down also increases the complexity of integrated circuit processing and fabrication.

Photolithography techniques form a patterned resist layer for various patterning processes, such as etching or ion implantation. The minimum feature size that can be patterned by such lithographic techniques is limited by the wavelength of the projection radiation source. Lithography machines have evolved from using ultraviolet light at 365 nm wavelengths to Deep Ultraviolet (DUV) light, including krypton fluoride laser (KrF laser) at 248 nm and argon fluoride laser (ArF laser) at 193 nm, and extreme ultraviolet light (EUV) at 13.5 nm wavelengths to improve resolution at each step.

Disclosure of Invention

According to some embodiments of the present disclosure, a method of processing a reticle includes: determining whether the particles are on the contact surface of the mask; cleaning the mask to remove the particles from the contact surface of the mask if the particles are on the contact surface; disposing the reticle on the chuck after cleaning the reticle, wherein the contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck; and performing a photolithography process using a mask disposed on the chuck.

According to some embodiments of the present disclosure, a method of processing a reticle includes: determining whether the particles are on the contact surface of the mask; if the particle is on the contact surface, determining the height of the particle; judging whether the height of the particles is less than the height; if the height of the particles is less than the predetermined height, disposing a reticle on the chuck, wherein a contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck; and performing a photolithography process using a mask disposed on the chuck.

According to some embodiments of the present disclosure, a lithographic apparatus includes a first compartment, an inspection system, a measurement system, a second compartment, a chuck, and a transfer mechanism. The inspection system is in the first compartment and is configured to determine whether particles are on the mask. A measurement system is within the first compartment and is configured to determine a height of the particle while the particle is on the reticle. The first compartment and the second compartment share a sidewall, and the sidewall has a channel communicating the first compartment and the second compartment. The suction cup is within the second compartment. The transfer mechanism is configured to transfer the reticle between the chuck, the inspection system, and the measurement system.

Drawings

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawing figures. It is noted that the various features are not necessarily drawn to scale. In fact, the dimensions and geometries of the various features may be arbitrarily increased or decreased for clarity of discussion.

FIG. 1 is a flow chart illustrating a method of mask processing according to some embodiments of the present disclosure;

FIG. 2 is a flow diagram depicting sub-operations of an operation of a method of mask processing, in accordance with some embodiments of the present disclosure;

FIG. 3 is a flow diagram illustrating sub-operations of an operation of a method of mask processing, according to some embodiments of the present disclosure;

FIG. 4 depicts a schematic diagram of a lithographic apparatus, according to some embodiments of the present disclosure;

FIG. 5 is a schematic diagram illustrating a first optical inspection module and a mask maintained in a first position in a lithography apparatus according to some embodiments of the present disclosure;

FIG. 6 is a schematic diagram illustrating a second optical inspection module and a mask maintained in a second position in a lithography apparatus according to some embodiments of the present disclosure;

FIG. 7 is a functional block diagram of a lithographic apparatus according to some embodiments of the present disclosure;

FIG. 8 is a schematic partial cross-sectional view of a lithographic apparatus according to some embodiments of the present disclosure.

Detailed Description

The following disclosure describes exemplary embodiments in order to implement various features of the subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. For example, it will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or one or more intervening elements may be present.

Additionally, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Furthermore, spatially relative terms, such as "under," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element (or elements) or feature (or features) as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Silicon wafers are manufactured in a series of sequential steps, including mask alignment, exposure, resist development, layer etching, and epitaxial layer growth, to form patterns that define device structures and interconnects within an Integrated Circuit (IC). To ensure robust reticle alignment, specialized alignment structures are placed within the physical layout data of the IC and used by online alignment tools within the semiconductor manufacturing flow to achieve Overlay (OVL) control during reticle alignment. The patterned wafer includes a plurality of ICs arranged in a periodic array or reticle field, where each reticle field is patterned by a step-and-repeat tool configured to align the patterned reticle to a separate reticle field based on a wafer map of the alignment structure. These alignment structures are obtained from the physical layout data of the IC. Yield and device performance rely on robust OVL control between two or more reticle alignment steps when forming layers of a device.

Accordingly, some embodiments of the present disclosure relate to methods of implementing enhanced overlay control. While the mask is held by the chuck, the contact surface of the mask that is used to contact the chuck is inspected to determine if particles are on the contact surface of the mask. If the particles are on the contact surface of the mask, the mask is cleaned to remove the particles from the contact surface of the mask. After the particles are removed from the contact surface of the reticle, the reticle is disposed on the chuck, wherein the contact surface of the reticle contacts the chuck. Since particles are removed from the contact surface of the reticle, the reticle does not have significant deformation when the contact surface of the reticle contacts the chuck, so overlay control can be enhanced.

Please refer to fig. 1. Fig. 1 is a flow chart illustrating a method 1000 of mask processing according to some embodiments of the present disclosure. The method 1000 begins with operation 1100: it is determined whether the particles are on the contact surface of the reticle. The mask processing method 1000 continues with operation 1200: if the particles are on the contact surface, the height of the particles is determined. The method 1000 continues with operation 1300: it is determined whether the height of the particles is less than a predetermined height. The method 1000 continues with operation 1400: if the height of the particles is greater than the predetermined height, the mask is cleaned. The mask processing method 1000 continues with operation 1500: the light shield is arranged on the sucker. The mask processing method 1000 continues with operation 1600: a photolithography process is performed using the mask.

Please refer to fig. 2. FIG. 2 is a flow diagram illustrating sub-operations of one operation 1100 of a method 1000 of mask processing, according to some embodiments of the present disclosure. Operation 1100 begins with sub-operation 1101: light is emitted toward the contact surface of the mask. Operation 1100 continues at sub-operation 1102: light reflected by the contact surface of the mask is detected. Operation 1100 continues at sub-operation 1103: light passing through the contact surface of the mask is detected. In some embodiments, if the mask is made of an opaque material, then sub-operation 1103 may be omitted.

Please refer to fig. 3. Fig. 3 is a flow diagram illustrating sub-operations of an operation 1200 of the mask processing method 1000, according to some embodiments of the present disclosure. Operation 1200 begins with sub-operation 1201: capturing a plurality of two-dimensional images of the particles at different heights. Operation 1200 continues with sub-operation 1202: the height of the particles is determined using a two-dimensional image of the particles.

The following discussion describes embodiments of a lithography apparatus 100 that may operate in accordance with the reticle handling method 1000 of FIGS. 1-3. While the reticle handling method 1000 is illustrated and described below as a series of acts or events, it should be appreciated that the illustrated ordering of such acts or events are not to be interpreted in a limiting sense. For example, some acts may occur in different orders and/or concurrently with other acts or events apart from those illustrated and/or described herein. In addition, not all illustrated acts may be required to implement a single feature or embodiment described in this disclosure. Further, one or more acts depicted in the present disclosure may be performed in one or more separate acts and/or phases.

Please refer to fig. 4. FIG. 4 is a schematic diagram illustrating a lithographic apparatus 100, according to some embodiments of the present disclosure. The lithographic apparatus 100 includes a housing 110, two load ports 120a, 120b, a robot 130, a first clamp 140a, and a second clamp 140 b. The housing 110 has a first compartment 111. Two load ports 120a, 120b are arranged on a first side of the first compartment 111 and communicate with the first compartment 111. Each of the two load ports 120a, 120b is configured to load the mask 200 into the first compartment 111 and configured to unload the mask 200 from the first compartment 111. The robot 130, the first gripper 140a, and the second gripper 140b are located in the first compartment 111. The robot 130 is configured to transfer the mask 200 between at least the two load ports 120a, 120b, the first gripper 140a, and the second gripper 140 b. For example, the robot 130 is configured to transfer the mask 200 from one of the two load ports 120a, 120b to the first gripper 140a, configured to transfer the mask 200 from the first gripper 140a to the second gripper 140b, and configured to transfer the mask 200 from the second gripper 140b to one of the two load ports 120a, 120b to unload the mask 200. The first clamp 140a is configured to hold the mask 200 in a first position within the first compartment 111. The second clamp 140b is configured to hold the mask 200 in a second position within the first compartment 111. In some embodiments, the first and second clamps 140a, 140b are adjacent to a second side of the first compartment 111 opposite to the first side where the two load ports 120a, 120b are located, and the robot 130 is between the two load ports 120a, 120b and the first and second clamps 140a, 140 b.

As shown in fig. 4, the housing 110 further has a second compartment 112. The second compartment 112 shares a side wall with the first compartment 111. The side wall has a channel 113 therein. The first compartment 111 communicates with the second compartment 112 via a passage 113. The lithographic apparatus 100 further comprises a turret 170 and a chuck 180. The turret 170 and suction cups 180 are located within the second compartment 112. The turret 170 is located between the channel 113 and the suction cup 180. The robot 130 is further configured to transfer the mask 200 from the first compartment 111 to the turret 170 via the channel 113, and configured to transfer the mask 200 from the turret 170 to the chuck 180 via the channel 113. The turret 170 is configured to transfer the mask 200 to the chuck 180 and is configured to remove the mask 200 from the chuck 180. The combination of the robot 130 and turret 170 may be considered a transfer mechanism configured to transfer the mask 200 between the chuck 180, the first gripper 140a, and the second gripper 140 b.

In some embodiments, the turret 170 is rotatable and includes two supports 171a, 171 b. The turret 170 is configured such that one of the supports 171a, 171b is adjacent to the channel 113 and the other is adjacent to the suction cup 180, and is configured to rotate to exchange the positions of the supports 171a, 171 b. In some embodiments, the mask 200 is transferred to one of the supports 171a, 171b adjacent the channel 113 by the robot 130, and the mask 200 may then be transferred to the chuck 180 by rotating the turret 170. In some embodiments, the mask 200 held on the chuck 180 may be removed by one of the supports 171a, 171b adjacent to the chuck 180, and the mask 200 may then be moved to adjacent the channel 113 and picked up by the robot 130 by rotating the turret 170. In other words, after another mask 200 has been transferred to one of the supports 171a, 171b adjacent to the channel 113, the mask 200 held on the chuck 180 may be exchanged for this other mask 200 by rotating the turret 170.

Please refer to fig. 5. FIG. 5 is a schematic diagram illustrating the first optical inspection module 150 and the mask 200 maintained in a first position by the first gripper 140a in the lithography apparatus 100 (see FIG. 4) according to some embodiments of the present disclosure. In some embodiments, as shown in fig. 5, the mask 200 includes a substrate 210 and a membrane element 220. The substrate 210 has a first surface 210a and a second surface 210b opposite to each other. Pellicle assembly 220 includes pellicle frame 221 and transparent pellicle 222. The film frame 221 is fixed to the first surface 210a of the substrate 210. The transparent film 222 is fixed above the film frame 221. The substrate 210 may be divided into a patterned region 210c and an unpatterned region 210d by a film frame 221. For example, a portion of the substrate 210 within a range surrounded by the film frame 221 may be regarded as a patterned region 210c, and a portion of the substrate 210 within a range outside the film frame 221 may be regarded as an unpatterned region 210 d. The membrane element 220 protects the patterned region 210c from the falling particles and keeps the particles away from focus so that they do not create a patterned image that may cause defects when the mask 200 is used in a lithography process. In some embodiments, the transparent film 222 is stretched and secured over the film frame 221 and attached to the film frame 221 by glue or other adhesive. The first clamp 140a is configured to abut opposing sidewalls of the substrate 210 of the mask 200 to thereby hold the mask 200 in the first position. The contact surface 210e of the mask 200 contacts the chuck 180 when the mask 200 is disposed on the chuck 180, and the contact surface 210e of the mask 200 is a portion of the first surface 210a located in the non-patterned region 210 d. That is, the contact surface 210e of the mask 200 is a portion of the first surface 210a not covered by the film element 220. In some embodiments, the reticle 200 has a plurality of non-patterned regions 210d, and the patterned regions 210c are located between the non-patterned regions 210 d.

In some embodiments, as shown in FIG. 5, the lithographic apparatus 100 (see FIG. 4) further comprises a first optical inspection module 150. The first optical inspection module 150 is configured to inspect the contact surface 210e of the mask 200 while the mask 200 is held by the first holder 140 a. The first optical inspection module 150 is disposed in the first compartment 111 (see fig. 4) and configured to determine whether the particles P are on the contact surface 210e of the mask 200. In some embodiments, the first optical detection module 150 is a dark field microscope or the like. Specifically, the first optical detection module 150 includes a light source 151a and a detector 152 a. The light source 151a is configured to emit light toward the contact surface 210e of the mask 200 when the mask 200 is held by the first holder 140 a. The detector 152a is configured to detect light reflected by the contact surface 210e of the mask 200. Thus, by analyzing the light reflected by the contact surface 210e of the mask 200, it can be determined whether the particles P are on the contact surface 210e of the mask 200. The detector 152a can be used to detect the particles P on the contact surface 210e of the mask 200, regardless of whether the substrate 210 of the mask 200 is a transmissive substrate or a reflective substrate. In some embodiments, as shown in fig. 5, when the mask 200 is held by the first holder 140a, the light source 151a and the detector 152a are on a side of the first holder 140a adjacent to the first surface 210a of the substrate 210 and away from the second surface 210 b.

In some embodiments, as shown in fig. 5, the first optical detection module 150 further comprises another detector 152 b. The detector 152b is configured to detect light passing through the mask 200. Thus, by analyzing the light reflected by the contact surface 210e of the mask 200 and the light passing through the mask 200, it can be determined whether the particles P are on the contact surface 210e of the mask 200. By comparing the results obtained by the detectors 152a, 152b, the detection of the particles P can be more accurate. In other words, if the substrate 210 of the mask 200 is a transparent substrate, the detector 152b can be further used to increase the precision of detecting the particles P. In some embodiments, the detector 152b may be turned off if the substrate 210 of the mask 200 is a reflective substrate. In some embodiments, detector 152b may be omitted because detector 152a can detect particles P whether substrate 210 is a transmissive substrate or a reflective substrate. In some embodiments, the substrate 210 of the mask 200 may comprise glass, quartz, silicon carbide, black diamond, combinations of the foregoing materials, or the like. In some embodiments, as shown in fig. 5, when the mask 200 is held by the first holder 140a, the detector 152b is on a side of the first holder 140a adjacent to the second surface 210b of the substrate 210 and away from the first surface 210 a.

In some embodiments, as shown in fig. 5, the first optical detection module 150 further comprises an objective lens 153. The objective lens 153 is configured to focus light emitted by the light source 151a on the contact surface 210e of the reticle 200.

In some embodiments, as shown in fig. 5, the first optical detection module 150 further comprises a beam splitter 154 and another detector 152 c. The beam splitter 154 is between the light source 151a and the objective lens 153, and is configured to split the light emitted by the light source 151a into a light beam directed to the contact surface 210e of the reticle 200 via the objective lens 153 and a light beam directed to the patterned region 210 c. The detector 152c is configured to detect light reflected by the transparent film 222 of the mask 200. In some embodiments, the light emitted from the light source 151a is laser light with a single wavelength, and the beam splitter 154 is a Polarization Beam Splitter (PBS) configured to split the laser light into two laser beams with different polarizations. Thus, by analyzing the light reflected by the transparent film 222 of the mask 200, contaminants (e.g., particles, dust, or the like) on the transparent film 222 of the film element 220 may be detected. In some embodiments, as shown in fig. 5, when the mask 200 is held by the first holder 140a, the beam splitter 154 and the detector 152c are on a side of the first holder 140a adjacent to the first surface 210a of the substrate 210 and away from the second surface 210 b.

In some embodiments, as shown in fig. 5, the first optical detection module 150 further includes another light source 151b and another detector 152 d. When the mask 200 is held by the first holder 140a, the light source 151b is configured to emit light toward the patterned region 210 c. The detector 152d is configured to detect light reflected by the patterned region 210c of the substrate 210 (i.e., reflected by the second surface 210 b). With this optical configuration, light emitted by the light source 151b will be reflected by the second surface 210 b. The light beam reflected by the second surface 210b is then received by the detector 152 d. As such, by analyzing the light reflected by the second surface 210b within the patterned region 210c, contaminants (e.g., particles, dust, or the like) on the second surface 210b within the patterned region 210c may be detected. In some embodiments, as shown in fig. 5, when the mask 200 is held by the first holder 140a, the light source 151b and the detector 152d are disposed on a side of the first holder 140a adjacent to the second surface 210b of the substrate 210 and away from the first surface 210a, and the light sources 151a and 151b are disposed on two opposite sides of the first holder 140 a.

In some embodiments, as shown in fig. 5, the first optical detection module 150 further comprises a reflector 155 a. Reflector 155a is configured to redirect light reflected by contact surface 210e of mask 200 toward detector 152 a. In some embodiments, as shown in fig. 5, the first optical detection module 150 further includes two reflectors 155b, 155 c. Reflector 155b is configured to redirect light passing through mask 200 toward reflector 155 c. Reflector 155c is configured to redirect light reflected by reflector 155b toward detector 152 b.

With the aforementioned optical configuration, the light emitted by the light source 151a is split into the first light beam and the second light beam by the beam splitter 154. The first light beam propagates toward the objective lens 153. The first light beam propagating toward the objective lens 153 is converged by the objective lens 153 and propagates to the contact surface 210 e. The first portion of the condensed first light pattern is reflected by the contact surface 210e and propagates to the reflector 155 a. A first portion of the first light beam propagating to reflector 155a is reflected by reflector 155a, propagates to detector 152a, and is then received by detector 152 a. The second portion of the condensed first light beam propagates through the substrate 210 toward the reflector 155 b. The second portion of the first light beam propagating to reflector 155b is reflected by reflector 155b and propagates to reflector 155 c. A second portion of the first light beam propagating to reflector 155c is reflected by reflector 155c, propagates to detector 152b, and is then received by detector 152 b. The second beam from the beam splitter 154 is reflected by the transparent film 222. The second light beam reflected by transparent film 222 is then received by detector 152 c. As such, by using the reflectors 155a, 155b, 155c, the physical size of the first optical detection module 150 can be flexibly adjusted.

In some embodiments, as shown in fig. 5, when the mask 200 is held by the first holder 140a, the light source 151a, the detectors 152a, 252c, the objective lens 153, the beam splitter 154 and the reflector 155a are on a side of the first holder 140a adjacent to the first surface 210a and away from the second surface 210b, and may be grouped into the first optical group 150a of the first optical inspection module 150. When the mask 200 is held by the first holder 140a, the light source 151b, the detectors 152b, 152d, and the reflectors 155b, 155c are on a side of the first holder 140a adjacent to the second surface 210b and away from the first surface 210a, and can be grouped into the second optical assembly 150b of the first optical inspection module 150.

In some embodiments, the first holder 140a and the first optical detection module 150 are movable relatively. In some embodiments, as illustrated in FIG. 5, the lithographic apparatus 100 comprises a movement module 135 a. When the mask 200 is held by the first gripper 140a, the moving module 135a is configured to move the first gripper 140a in a direction a1 substantially parallel to the substrate 210 of the mask 200. In some embodiments, as illustrated in FIG. 5, the lithographic apparatus 100 further comprises a movement module 135b, 135 c. When the mask 200 is held by the first gripper 140a, the moving module 135b is configured to move the first optics group 150a in the direction a1, and the moving module 135c is configured to synchronously move the second optics group 150b in the direction a 1. In other words, the direction a1 may be substantially perpendicular to the sidewall of the first clamp 140a, the sidewall of the first clamp 140a being configured to abut against the sidewall of the substrate 210 of the mask 200. In some embodiments, at least one of the moving modules 135a, 135b, 135c is a linear actuator that can generate a linear motion to move one of the first gripper 140a, the first optical assembly 150a, and the second optical assembly 150b in a straight line along the direction a 1. In other embodiments, when the mask 200 is held by the first holder 140a, at least one of the moving modules 135a, 135b, 135c is a two-dimensional moving module that can generate motion to move one of the first holder 140a, the first optical assembly 150a, and the second optical assembly 150b in a plane substantially parallel to the substrate 210. In some other embodiments, at least one of the moving modules 135a, 135b, 135c is a three-dimensional moving module that generates three-dimensional motion to move one of the first gripper 140a, the first optical assembly 150a, and the second optical assembly 150 b. In some embodiments, the moving module 135a may be omitted. In some embodiments, the movement modules 135b, 135c may be omitted. In some embodiments, the moving module 135b is configured to move one or more components of the first optical assembly 150a in the direction a 1. In some embodiments, the moving module 135c is configured to move one or more components of the second optical assembly 150b in the direction a 1.

Please refer to fig. 6. FIG. 6 is a schematic diagram illustrating the second optical inspection module 160 and the mask 200 maintained in the second position by the second clamp 140b in the lithography apparatus 100 according to some embodiments of the present disclosure. When the mask 200 is held by the second holder 140b, the second optical inspection module 160 is disposed on a side of the second holder 140b adjacent to the first surface 210a and away from the second surface 210b of the substrate 210, and is configured to measure the height of the particles P. The second optical inspection module 160 is disposed in the first compartment 111 and configured to determine the height of the particles P when the particles P are on the contact surface 210e of the mask 200. In some embodiments, the second optical detection module 160 is a confocal microscope, such as a confocal laser scanning microscope. Specifically, the second optical detection module 160 includes a light source 161, a dichroic mirror 162, an objective lens 163, a confocal aperture 164, and a detector 165. The dichroic mirror 162 is configured to reflect a portion of the light emitted by the light source 161 toward the contact surface 210e of the mask 200. The objective lens 163 is configured to focus the light reflected by the dichroic mirror 162 on the contact surface 210e of the reticle 200. The dichroic mirror 162 is between the objective lens 163 and the confocal aperture 164, and the confocal aperture 164 is between the dichroic mirror 162 and the detector 165. In other words, the objective lens 163, the dichroic mirror 162, the confocal aperture 164, and the detector 165 are sequentially arranged in a line. The detector 165 is arranged to obtain an image sequentially through the confocal aperture 164, dichroic mirror 162 and objective lens 163. In some embodiments, the detector 165 is a photomultiplier tube (PMT) or the like.

With the aforementioned optical configuration, light emitted by the light source 161 is at least partially reflected by the dichroic mirror 162 and then propagates toward the objective lens 163. The reflected light beam is converged by the objective lens 163 and propagates to the contact surface 210 e. The condensed light beam is reflected by the contact surface 210e, propagates through the dichroic mirror 162 and the confocal aperture 164, and is received by the detector 165. In some embodiments, the light beam reflected by dichroic mirror 162 and propagating toward objective lens 163 has a first wavelength (e.g., a wavelength in the range of about 450nm to about 495 nm), while the light beam reflected by contact surface 210e has a second wavelength (e.g., a wavelength in the range of about 495nm to about 570 nm) and is allowed to propagate through dichroic mirror 162. In some embodiments, the light beam emitted by the light source 161 is a white light beam (e.g., having a wavelength of about 380nm to about 780 nm). In some embodiments, the light beam emitted by the light source 161 is a laser beam having a single wavelength, and the wavelength is selected such that the light beam is reflected by the dichroic mirror 162.

In some embodiments, the second holder 140b and the second optical detection module 160 are movable relatively. In some embodiments, as shown in FIG. 6, the lithographic apparatus 100 includes a movement module 135 d. When the mask 200 is held by the second gripper 140b, the moving module 135d is configured to move the second gripper 140b in a direction a2 substantially perpendicular to the substrate 210 of the mask 200. In some embodiments, as shown in FIG. 6, the lithographic apparatus 100 further comprises a movement module 135 e. The moving module 135e is configured to move the second optical detection module 160 in the direction a 2. In other words, the direction a2 can be parallel to the sidewall of the second clamp 140b, and the sidewall of the second clamp 140b is configured to abut against the sidewall of the substrate 210 of the mask 200. In some embodiments, at least one of the moving modules 135d, 135e is a linear actuator capable of generating a linear motion to move one of the second clamp 140b and the second optical detection module 160 in a straight line along the direction a2, but the disclosure is not limited thereto. In other embodiments, when the mask 200 is held by the second holder 140b, at least one of the moving modules 135d, 135e is a two-dimensional moving module that can generate motion to move one of the second holder 140b and the second optical inspection module 160 in a plane substantially parallel to the substrate 210 of the mask 200. In some other embodiments, at least one of the moving modules 135d, 135e is a three-dimensional moving module capable of generating three-dimensional motion to move one of the second clamp 140b and the second optical detection module 160. In some embodiments, one of the movement modules 135d, 135e may be omitted. In some embodiments, the moving module 135e is configured to move one or more components (e.g., the objective lens 163) in the second optical detection module 160 in the direction a 2.

Please refer to fig. 4, 5 and 7. FIG. 7 is a functional block diagram illustrating a lithographic apparatus 100, according to some embodiments of the present disclosure. The lithographic apparatus 100 further comprises a controller 190. The controller 190 is electrically connected to the robot 130. In some embodiments, when the mask 200 is loaded by one of the two load ports 120a, 120b, the controller 190 controls the robot 130 to transfer the mask 200 to the first position to be held by the first clamp 140 a. The first optical inspection module 150 then inspects the contact surface 210e of the mask 200. The controller 190 is also configured to determine whether particles are on the contact surface 210e of the mask 200 by analyzing the image received by the first optical inspection module 150. Specifically, the controller 190 can control the moving modules 135a, 135b, 135c to move the first gripper 140a, the first optical assembly 150a, and the second optical assembly 150b, respectively, so as to completely or partially scan, for example, the contact surface 210e, the first surface 210a in the unpatterned region 210d, the transparent film 222, and/or the second surface 210b through the first optical detection module 150.

In some embodiments, the controller 190 is further configured to control the light source 151a to emit light toward the contact surface 210e of the mask 200 when the mask 200 is held by the first holder 140 a. The controller 190 is configured to receive the image from the detector 152a and configured to determine the presence and location of the particles P on the contact surface 210e of the mask 200 by analyzing the image received by the detector 152 a. In some embodiments, the controller 190 is further configured to receive the image from the detector 152b and configured to determine the presence and location of the particle P on the contact surface 210e of the mask 200 by analyzing the image received from the detector 152 b. If the particle P is on the contact surface 210e of the mask 200, the controller 190 is further configured to control the robot 130 to move the mask 200 from the first position to the second position to be held by the second holder 140 b. The detection result may also include the position of the particles P on the contact surface 210e of the mask 200.

In some embodiments, the controller 190 is further configured to determine whether a contaminant (e.g., a particle, dust, or the like) is on the transparent film 222 of the film assembly 220. In some embodiments, the controller 190 is configured to control the light source 151a to emit light toward the transparent film 222 when the mask 200 is held by the first holder 140 a. Controller 190 is configured to receive the image from detector 152c and is configured to determine the presence and location of contaminants on transparent film 222 by analyzing the image received from detector 152 c.

In some embodiments, the controller 190 is further configured to determine whether a contaminant (e.g., a particle, dust, or the like) is on the second surface 210b of the substrate 210. In some embodiments, the controller 190 is configured to control the light source 151b to emit light toward the second surface 210b of the substrate 210 when the mask 200 is held by the first holder 140 a. The controller 190 is configured to receive the image from the detector 152d and configured to determine the presence and location of contaminants on the second surface 210b of the substrate 210 by analyzing the image received from the detector 152 d.

Please refer to fig. 4, fig. 6 and fig. 7. In some embodiments, the second optical detection module 160 then determines the height of the particle P at the second position. Specifically, the controller 190 can control the moving module 135e to move the second optical detection module 160 to capture a plurality of images of the particle P at different heights. The controller 190 is configured to control the light source 161 to emit light and is configured to receive an image of the particle P from the detector 165. These images are two-dimensional images. The focal plane of the light reflected by the dichroic mirror 162 is parallel to the contact surface 210e of the mask 200. The height of the particles P can be determined based on whether the particles P are present in the image. For example, if a particle P is present in one image and not present in the next image, the height of the focal plane corresponding to the previous image relative to the contact surface 210e of the mask 200 can be considered as the height of the particle P.

In some embodiments, the controller 190 is configured to control the robot 130 to move the mask 200 from the second position to one of the load ports 120a, 120b to unload the mask 200 when the height of the particles P is determined to be greater than the predetermined height. In some embodiments, the mask 200 may then be cleaned to remove the particles P from the contact surface 210e of the mask 200. In some embodiments, the mask 200 may be cleaned by a tool external to the lithographic apparatus 100. In some embodiments, after the mask 200 is cleaned, the contact surface 210e of the mask 200 is determined again whether there are particles P.

In some embodiments, the controller 190 is configured to control the robot 130 to move the mask 200 from the first position to one of the load ports 120a, 120b to unload the mask 200 when a particle P is determined to be present on the contact surface 210e of the mask 200. Regardless of whether the height of the particles P is greater than the predetermined height, the mask 200 is then cleaned to remove the particles P from the contact surface 210e of the mask 200.

In some embodiments, the controller 190 is configured to control the robot 130 to move the mask 200 from the second position to the chuck 180 with the assistance of the turret 170 when the height of the particle P is determined to be less than the predetermined height. In some embodiments, the mask 200 is moved to the chuck 180 when the height of the particles P is determined to be less than about 40 μm. If particles P having a height greater than about 40 μm are on the contact surface 210e of the reticle 200, the reticle 200 may have significant deformation when the contact surface 210e of the reticle 200 contacts the chuck 180. In some embodiments, the controller 190 is configured to control the robot 130 to move the mask 200 from the first position to the chuck 180 with the assistance of the turret 170 when no particles P are detected.

As shown in fig. 4, the robot 130 may first move the mask 200 to the turret 170 via the channel 113, and the turret 170 may then rotate to transfer the mask 200 to the chuck 180. Then, the mask 200 is held by the chuck 180, and the photolithography process is performed using the held mask 200. In some embodiments, after performing the photolithography process, the mask 200 may be transferred to one of the load ports 120a, 120b via the turret 170 and the robot 130 in sequence for unloading. The suction cup 180 holds the mask 200 by suction. In some embodiments, the controller 190 may comprise a plurality of processing units arranged in the lithographic apparatus 100, and the above-described functions of the controller 190 may be allocated to be performed by these processing units.

Please refer to fig. 8. FIG. 8 is a partial cross-sectional schematic diagram illustrating a lithographic apparatus 100, according to some embodiments of the present disclosure. The lithographic apparatus 100 further comprises a light source 181, a shutter 182, lenses 183a, 183b, and a wafer stage 184. The chuck 180 is configured to hold a substrate 210 of the mask 200. The contact surface 210e of the mask 200 contacts the chuck 180. Light source 181 is above chuck 180. The shutter 182 is between the suction cup 180 and the light source 181, and has an exposure slit 182 a. The lens 183a is between the blocking plate 182 and the chuck 180, and is configured to focus light emitted from the light source 181 on the substrate 210. A wafer stage 184 is below the chuck 180 and is configured to support a wafer W thereon. The lens 183b is between the wafer stage 184 and the chuck 180 and is configured to focus light passing through the substrate 210 onto the wafer W. With this optical configuration, light emitted from the light source 181 propagates to the lens 183a via the exposure slit 182a of the shutter 182. The light transmitted to the lens 183a is converged by the lens 183b and transmitted to the wafer W. The lithographic apparatus 100 is configured to perform a lithographic process that transfers a pattern of the geometry on the substrate 210 to a thin layer of photosensitive material (referred to as photoresist) that covers the surface of the wafer W. The exposure method used by the lithographic apparatus 100 is projection printing or the like. In some embodiments, the lithographic apparatus 100 uses a stepper, referred to as a scanner, which moves the wafer stage 184 and the chuck 180 relative to each other during exposure as a means of increasing the size of the exposure field and increasing the imaging performance of the lenses 183a, 183 b.

By monitoring and controlling the topography of the contact surface 210e of the reticle 200, the reticle 200 does not have significant deformation when the contact surface 210e of the reticle 200 contacts the chuck 180. Thus, the overlay control can be enhanced.

In some embodiments, a method of processing a reticle includes determining whether particles are on a contact surface of the reticle. If particles are on the contact surface, the mask is cleaned to remove the particles from the contact surface of the mask. After cleaning the reticle, the reticle is disposed on the chuck, wherein the contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck. The photolithography process is performed using a mask disposed on a chuck.

In some embodiments, the method further comprises determining again whether particles are on the contact surface of the reticle after cleaning the reticle.

In some embodiments, the step of determining whether the particles are on the contact surface of the reticle and the step of disposing the reticle on the chuck are performed in the same tool.

In some embodiments, the step of determining whether particles are on the contact surface of the reticle is performed using dark field inspection.

In some embodiments, a reticle has a patterned region and an unpatterned region. The contact surface of the reticle is within the unpatterned region.

In some embodiments, a reticle has a plurality of non-patterned regions and patterned regions located between the non-patterned regions. The contact surface of the reticle is within a plurality of non-patterned regions.

In some embodiments, a mask includes a substrate and a pellicle assembly. The film assembly covers a portion of the substrate. The contact surface of the mask is not covered by the pellicle.

In some embodiments, the step of determining whether particles are on the contact surface of the reticle and the step of cleaning the reticle are performed in different tools.

In some embodiments, a method of processing a reticle includes determining whether particles are on a contact surface of the reticle. If the particles are on the contact surface, the height of the particles is determined. The height of the particles is judged to be less than the height. If the height of the particles is less than the predetermined height, a reticle is disposed on the chuck, wherein a contact surface of the reticle contacts the chuck when the reticle is disposed on the chuck. A mask disposed on the chuck is utilized to perform a photolithography process.

In some embodiments, the method further comprises cleaning the mask if the height of the particles is greater than a predetermined height.

In some embodiments, the step of determining the height of the particles is performed using a confocal laser scanning microscope.

In some embodiments, the step of determining the height of the particle comprises capturing a plurality of two-dimensional images of the particle at different heights. Multiple two-dimensional images of the particle are utilized to determine the height of the particle.

In some embodiments, the step of determining whether the particles are on the contact surface of the reticle and the step of determining the height of the particles are performed in the same tool.

In some embodiments, the method further comprises holding the reticle with a holder contacting opposing sidewalls of the reticle when determining whether the particles are on the contact surface of the reticle.

In some embodiments, the method further comprises holding the reticle with a holder contacting opposing sidewalls of the reticle while determining the height of the particles.

In some embodiments, a lithographic apparatus includes a first compartment, an inspection system, a measurement system, a second compartment, a chuck, and a transfer mechanism. The inspection system is in the first compartment and is configured to determine whether particles are on the mask. A measurement system is within the first compartment and is configured to determine a height of the particle while the particle is on the reticle. The first compartment and the second compartment share a sidewall, and the sidewall has a channel communicating the first compartment and the second compartment. The suction cup is within the second compartment. The transfer mechanism is configured to transfer the reticle between the chuck, the inspection system, and the measurement system.

In some embodiments, the detection system comprises a dark field microscope.

In some embodiments, the measurement system comprises a confocal microscope.

In some embodiments, the lithographic apparatus further comprises a load port in communication with the first compartment.

In some embodiments, the detection system is configured to detect an unpatterned region of the reticle.

The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that the present disclosure may be readily utilized as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. It should be emphasized that many variations and modifications to the above-described embodiments may be effected, the elements of which are to be understood as being among other acceptable examples. Such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.