TWI685725B - Inspection tool, lithographic apparatus, lithographic system, inspection method and device manufacturing method - Google Patents

Abstract

An inspection tool for inspecting a semiconductor substrate is described, the inspection tool comprising: - an substrate table configured to hold the substrate; - an electron beam source configured to project an electron beam onto an area of interest of the substrate, the area of interest comprising a buried structure; - a cathodoluminescent detector configured to detect cathodoluminescent light emitted from the buried structure; - a control unit configured to: - control the electron beam source to project to electron beam onto the area of interest; - receive a signal representative of the detected cathodoluminescent light; - determine, based on the signal, a characteristic of the buried structure.

Description

Detection tool, lithography equipment, lithography system, detection method and device manufacturing method

The invention relates to a detection tool, a lithography equipment, a lithography system, a detection method and a method for manufacturing devices.

A lithography apparatus is a machine that applies a desired pattern to a substrate (usually to a target portion of the substrate). Lithography equipment can be used, for example, in the manufacture of integrated circuits (ICs). In this situation, a patterned device (which is instead referred to as a reticle or a reticle) can be used to generate circuit patterns to be formed on individual layers of the IC. This pattern can be transferred to a target part (for example, a part including a die, a die, or several die) on a substrate (for example, a silicon wafer). Pattern transfer is usually performed by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. Generally speaking, a single substrate will contain a network of adjacent target portions that are sequentially patterned. The conventional lithography apparatus includes: a so-called stepper, in which each target part is irradiated by exposing the entire pattern to the target part at once; and a so-called scanner, in which by scanning in a given direction ("scan In the "direction", the scanning pattern is simultaneously scanned in parallel or anti-parallel to the direction via the radiation beam to irradiate each target portion. It is also possible to transfer the pattern from the patterned device to the substrate by imprinting the pattern onto the substrate.

The radiation beam generally applied in the lithography apparatus may be, for example, a DUV radiation beam (for example, having a wavelength of 248 nanometers or 193 nanometers) or an EUV radiation beam (for example, having a wavelength of 11 nanometers or 13.5 nanometers).

The manufacture of integrated circuits may generally require the stacking of multiple layers, where the layers need to be accurately aligned. Without this alignment, the required connection between the layers may be defective, causing the integrated circuit to malfunction.

Typically, the bottom layer of the integrated circuit will contain minimal structures, such as transistors or their components. The structure of subsequent layers is usually larger and connects the structure in the bottom layer with the outside world. In view of this, the alignment of the two layers will be the most challenging in the bottom part of the integrated circuit.

To achieve this alignment, a layer usually made of a plurality of alignment marks provided on the substrate is used, the position of the alignment marks indicating the position of the patterned structure. Due to the various program steps performed between the exposure procedures of two consecutive layers, it may be cumbersome to determine the actual position of the alignment mark. In detail, processing steps such as CMP can cause deformation of the alignment mark. Therefore, the determination of the actual position of the alignment mark may be defective, resulting in an incorrect or inaccurate assessment of the position of the patterned structure.

In the case of an incorrect evaluation of the position of the alignment mark, overlay errors can be caused during the exposure process, and the next patterned layer is generated by the exposure process. This error can affect the functionality of the fabricated semiconductor device.

It will be beneficial to assess whether the desired functionality of the semiconductor device will be satisfied early in the manufacturing process.

There is a need to enable an early assessment of whether the semiconductor device will have the desired functionality.

According to an embodiment of the present invention, there is provided an inspection tool for inspecting a semiconductor substrate, the inspection tool includes-a substrate stage configured to hold the substrate;-an electron beam source configured to use An electron beam is projected onto a region of interest of the substrate, the region of interest includes an embedded structure;-a cathode luminescence detector configured to detect cathode luminescence emitted from the embedded structure Light;-a control unit configured to:-receive a signal representing the detected light emitted by the cathode;-determine a characteristic of the embedded structure based on the signal.

According to an embodiment of the present invention, there is provided a lithography apparatus comprising:-an illumination system configured to adjust a radiation beam;-a support member configured to support a patterned device, the patterned The device is capable of imparting a pattern to the radiation beam in the cross-section of the radiation beam to form a patterned radiation beam; a projection system configured to project the patterned radiation beam onto a target portion of a substrate Above; wherein the device further includes a detection tool according to the present invention and a stage device, the stage device is configured to position the substrate table to impart the patterned radiation beam to the substrate.

According to an embodiment of the present invention, there is provided a lithography system, which includes:-a lithography device, which includes:-an illumination system configured to adjust a radiation beam; -A support member constructed to support a patterned device capable of imparting a pattern to the radiation beam in the cross-section of the radiation beam to form a patterned radiation beam;-a projection system whose warp Configured to project the patterned radiation beam onto a target portion of a substrate;-a stage device configured to position the substrate table to impart the patterned radiation beam to the substrate;-a The detection tool according to the invention.

According to an embodiment of the present invention, a detection method is provided. The method includes the following steps:-providing a substrate having an area of interest, the area of interest including an embedded structure;-scanning the area of interest using an electron beam Area;-capture CL-light emitted from the area of interest;-determine one of the characteristics of the buried structure.

According to an embodiment of the present invention, a device manufacturing method is provided, which includes projecting a patterned radiation beam onto a substrate, wherein the step of projecting the patterned radiation beam onto the substrate is detected according to the invention Before the method.

100‧‧‧Test tool

110‧‧‧ electron beam source

112‧‧‧Control signal

120‧‧‧ electron beam

130‧‧‧Object

132‧‧‧Object table

134‧‧‧ clamping mechanism

140‧‧‧CL-light/arrow

142‧‧‧CL-light/arrow

150‧‧‧detector

152‧‧‧Signal

160‧‧‧Reflector

170‧‧‧Aperture/Control Unit

172‧‧‧Input terminal

174‧‧‧Output terminal

200‧‧‧ Spectrum

400‧‧‧Semiconductor structure/region of interest

402‧‧‧Bottom layer/adjacent structure

404‧‧‧Structure

406‧‧‧Structure

408‧‧‧Top layer/material

410‧‧‧ electron beam

412‧‧‧Top surface/area

414‧‧‧Interaction volume

420‧‧‧arrow

430‧‧‧ height or depth

500‧‧‧ area of interest

502‧‧‧ storey

508‧‧‧ storey

510‧‧‧Buried structure

510.1‧‧‧Extended vertical structure

510.2‧‧‧Enclosure structure

512‧‧‧Surface/Area

514‧‧‧Interaction volume

515‧‧‧ electron beam

520‧‧‧arrow

600‧‧‧curve

610‧‧‧curve

700‧‧‧Image

710‧‧‧ District

720 District

800‧‧‧ video

810‧‧‧ District

District 820‧‧‧

District 830‧‧‧

District 840‧‧‧

900‧‧‧Image

1000‧‧‧ Stacked pair of marks/area of interest

1005‧‧‧ storey

1010‧‧‧patterned bottom

1012‧‧‧First structure/surface/area

1014‧‧‧Interaction volume

1015‧‧‧ electron beam

1016‧‧‧ direction

1020‧‧‧Top patterned layer

1022‧‧‧Second structure

1030‧‧‧ storey

1200‧‧‧Test tool

1230‧‧‧Sample

1232‧‧‧Surface

1240‧‧‧Buried structure

1250‧‧‧Laser beam

1260‧‧‧Sonic

1270‧‧‧Strain distribution

AD‧‧‧Adjuster

B‧‧‧radiation beam

BD‧‧‧beam delivery system

C‧‧‧Target part

CO‧‧‧Concentrator

FS1‧‧‧First Spectrum

FS2‧‧‧second spectrum

IF‧‧‧Position sensor

IL‧‧‧Lighting system/illuminator

IN‧‧‧Integrator

IT‧‧‧Test Tool

M1‧‧‧ Mask alignment mark

M2‧‧‧ Mask alignment mark

MA‧‧‧patterned device/mask

MT‧‧‧mask support structure/mask table

P1‧‧‧Substrate alignment mark

P2‧‧‧Substrate alignment mark

PM‧‧‧First positioning device

PS‧‧‧Projection system

PW‧‧‧Second positioning device

SO‧‧‧radiation source

W‧‧‧Substrate

Wd‧‧‧Width

WT‧‧‧Substrate table

Embodiments of the present invention will now be described with reference to the accompanying schematic drawings as examples only. In these drawings, corresponding reference symbols indicate corresponding parts, and in these drawings: FIG. 1 depicts The lithography apparatus of the embodiment; FIG. 2 depicts a detection tool according to an embodiment of the present invention; 3 depicts the spectrum of CL-light that can be determined by the detection tool according to the present invention; FIG. 4 schematically depicts a cross-sectional view of a structure that can be inspected using the detection tool according to the present invention; FIG. 5 schematically depicts the available tool according to the present invention. A cross-sectional view of another structure inspected by the inventive inspection tool; FIG. 6 schematically depicts the change in the spectrum of the received CL-light along the area of interest.

7 to 9 schematically show possible images of the area of interest derived from captured CL-light.

FIG. 10 schematically depicts a cross-sectional view of the overlay mark that can be inspected using the inspection tool according to the invention.

FIG. 11 schematically depicts the CL-light spectrum and the modified spectrum that can be determined by the detection tool according to the invention.

FIG. 12 schematically illustrates an embodiment of a detection tool according to the invention, in which sound waves can be generated.

Fig. 1 schematically depicts a lithographic apparatus according to an embodiment of the invention. The device includes: a lighting system (illuminator) IL, which is configured to adjust the radiation beam B (eg, UV radiation or any other suitable radiation); a mask support structure (eg, mask stage) MT, which is constructed to support the pattern The device (eg, photomask) MA is connected to the first positioning device PM configured to accurately position the patterned device according to certain parameters. The device also includes a substrate table (e.g., wafer table) WT or "substrate support" that is constructed to hold the substrate (e.g., resist-coated wafer) W and is connected to be configured to accurately according to certain parameters Position the second positioning device PW of the substrate. The device into One step includes a projection system (eg, a refractive projection lens system) PS configured to project the pattern imparted to the radiation beam B by the patterning device MA onto the target portion C (eg, including one or more dies) of the substrate W.

The lighting system may include various types of optical components for directing, shaping, or controlling radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.

The reticle support structure supports (ie, carries) the patterned device. The reticle support structure holds the patterned device in a manner that depends on the orientation of the patterned device, the design of the lithography equipment, and other conditions (such as whether the patterned device is held in a vacuum environment). The reticle support structure may use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterned device. The reticle support structure may be, for example, a frame or a table, which may be fixed or movable according to needs. The reticle support structure can ensure that the patterned device (for example) is in a desired position relative to the projection system. It can be considered that any use of the term "reduced reticle" or "reticle" herein is synonymous with the more general term "patterned device".

The term "patterned device" as used herein should be broadly interpreted as referring to any device that can be used to impart a pattern to the radiation beam in the cross-section of the radiation beam in order to create a pattern in the target portion of the substrate. It should be noted that, for example, if the pattern assigned to the radiation beam includes phase-shifting features or so-called auxiliary features, the pattern may not exactly correspond to the desired pattern in the target portion of the substrate. Generally, the pattern assigned to the radiation beam will correspond to a specific functional layer in the device (such as an integrated circuit) produced in the target portion.

The patterned device may be transmissive or reflective. Examples of patterned devices include photomasks, programmable mirror arrays, and programmable LCD panels. Masks are well known to me in lithography, and include mask types such as binary, alternating phase shift, and attenuation phase shift, as well as various blends Type of reticle. An example of a programmable mirror array uses a matrix configuration of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The inclined mirror surface gives a pattern to the radiation beam reflected by the mirror matrix.

The term "projection system" as used herein should be broadly interpreted to cover any type of projection system suitable for the exposure radiation used or for other factors such as the use of immersion liquids or the use of vacuum, including refraction, Reflection, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof. It can be considered that any use of the term "projection lens" herein is synonymous with the more general term "projection system".

As depicted here, the device is of the transmissive type (for example, using a transmissive mask). Alternatively, the device may be of the reflective type (for example, using a programmable mirror array of the type mentioned above, or using a reflective mask).

Lithography equipment may belong to two (dual stage) or more than two substrate tables or "substrate supports" (and/or two or more than two mask tables or "mask supports") Types of. In these "multi-stage" machines, additional tables or supports can be used in parallel, or one or more tables or supports can be prepared, while one or more other tables or supports can be used simultaneously exposure.

Lithography equipment can also be of the type in which at least a portion of the substrate can be covered by a liquid with a relatively high refractive index, such as water, to fill the space between the projection system and the substrate. The infiltrating liquid can also be applied to other spaces in the lithography equipment, for example, the space between the reticle and the projection system. The infiltration technique can be used to increase the numerical aperture of the projection system. The term "wetting" as used herein does not mean that a structure such as a substrate must be submerged in liquid, but only means that the liquid is located between the projection system and the substrate during exposure.

Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. For example In other words, when the source is an excimer laser, the source and the lithography equipment can be separate entities. Under these circumstances, the source is not considered to form part of the lithographic apparatus, and the radiation beam is transferred from the source SO to the illuminator IL by means of a beam delivery system BD that includes, for example, a suitable guide mirror and/or beam expander. In other situations, for example, when the source is a mercury lamp, the source may be an integral part of the lithography device. The source SO and illuminator IL together with the beam delivery system BD (when needed) may be referred to as a radiation system.

The illuminator IL may include an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Generally, at least the outer radial range and/or the inner radial range of the intensity distribution in the pupil plane of the illuminator can be adjusted (commonly referred to as σouter and σinner, respectively). In addition, the illuminator IL may include various other components, such as an integrator IN and a condenser CO. The illuminator can be used to adjust the radiation beam to have the desired uniformity and intensity distribution in its cross-section.

The radiation beam B is incident on a patterned device (eg, reticle MA) held on a reticle support structure (eg, reticle stage MT), and is patterned by the patterned device. With the mask MA traversed, the radiation beam B passes through the projection system PS, which focuses the beam onto the target portion C of the substrate W. With the aid of the second positioning device PW and the position sensor IF (such as an interferometric measuring device, a linear encoder or a capacitive sensor), the substrate table WT can be accurately moved, for example, to position the different target parts C on the radiation beam B In the path. Similarly, the first positioning device PM and another position sensor (which are not explicitly depicted in FIG. 1) can be used, for example, after the mechanical extraction from the reticle library or during scanning, the path relative to the radiation beam B is accurate Position the photomask MA. Generally speaking, the movement of the reticle stage MT can be realized by means of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) that form part of the first positioning device PM. Similarly, a long-stroke module and a short-stroke module that form part of the second positioning device PW can be used to achieve the movement of the substrate table WT or "substrate support". In the case of a stepper (relative to a scanner), the mask stage MT may only be connected to a short-stroke actuator, or may be fixed. Mask can be used to mark Mark M1 and M2 and the substrate alignment marks P1 and P2 to align the mask MA and the substrate W. Although the illustrated substrate alignment marks occupy dedicated target portions, the marks may be located in the space between the target portions (these marks are referred to as scribe lane alignment marks). Similarly, in the case where more than one die is provided on the mask MA, the mask alignment mark may be located between the die.

The depicted device can be used in at least one of the following modes:

1. In the step mode, when the entire pattern imparted to the radiation beam is projected onto the target portion C at once, the reticle stage MT or "reticle support" and the substrate stage WT or "substrate support" remain basic Up still (that is, a single static exposure). Next, the substrate table WT or "substrate support" is displaced in the X and/or Y directions so that different target portions C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

2. In the scanning mode, when the pattern imparted to the radiation beam is projected on the target portion C, the reticle stage MT or "reticle support" and the substrate stage WT or "substrate support" (also (Single dynamic exposure). The speed and direction of the substrate table WT or "substrate support" relative to the reticle stage MT or "reticle support" can be determined by the magnification (reduction ratio) and image reversal characteristics of the projection system PS. In the scanning mode, the maximum size of the exposure field limits the width of the target portion in a single dynamic exposure (in the non-scanning direction), and the length of the scanning motion determines the height of the target portion (in the scanning direction).

3. In another mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the reticle stage MT or "reticle support" is kept substantially still, thereby holding the programmable patterned device , And move or scan the substrate table WT or "substrate support". In this mode, typically, a pulsed radiation source is used and the programmable patterned device is updated as needed after each movement of the substrate table WT or "substrate support" or between successive radiation pulses during scanning. this The operating mode can be easily applied to maskless lithography using programmable patterned devices, such as the programmable mirror arrays of the type mentioned above.

Combinations and/or variations or completely different modes of use of the modes of use described above may also be used.

In the embodiment as shown, the lithographic apparatus further comprises the detection tool IT according to the invention. This inspection tool IT can, for example, enable the determination of the characteristics of the structure, in particular the buried structure present on or in the area of interest of the substrate W processed by the lithographic apparatus. In an embodiment, as will be discussed in more detail below, the inspection tool may include an electron beam source for inspecting the substrate.

In an embodiment, the second positioning device PW may be configured to position the substrate W in the operating range of the inspection tool IT. In this embodiment, the inspection tool IT may, for example, be configured to determine the characteristics of the mentioned structure, such as electrical characteristics, material characteristics, and/or geometric characteristics. In an embodiment, this information can then be provided to the control unit of the lithography apparatus and used during the exposure process, for example by controlling one or more of the lighting system, projection system or positioning device based on the information .

In the embodiment as shown, the lithographic apparatus may be configured to apply DUV radiation for radiating the light beam. In this case, the patterned device MA may be a transmission patterned device and the projection system PS may include one or more lenses.

Alternatively, the lithographic apparatus according to the present invention may be configured to apply EUV radiation for radiating light beams. In this case, the patterned device MA may be a reflective patterned device and the projection system PS may include one or more mirror surfaces. In this embodiment, the apparatus may include one or more vacuum chambers for housing the illumination system IL and/or the projection system PS.

According to one aspect of the invention, a configuration is provided to detect, for example, a substrate Object detection tool. FIG. 2 schematically shows an embodiment of this inspection tool 100. According to the present invention, the inspection tool 100 includes an electron beam source 110, which is also referred to as an e-beam source 110.

Generally speaking, this electron beam source 110 is known and can be used in the present invention to project the electron beam 120 onto the area of an object 130 such as a substrate. In the embodiment as shown, the object 130 is mounted to the object table 132 by means of a clamping mechanism 134 (eg vacuum clamp or electrostatic clamp). The area of the object onto which the electron beam is projected can also be called a sample. The electron beam source 110 can be used, for example, to generate an electron beam 120 having an energy ranging from 0.2 keV to 100 keV. The electron beam source 110 may generally have one or more lenses for focusing the electron beam 120 onto a light spot having a diameter of about 0.4 to 5 nanometers. In an embodiment, the electron beam source 110 may further include one or more scanning coils or polarizer plates, which may deflect the electron beam 120. Thereby, the electron beam 120 can be deflected, for example, along the X axis and the Y axis (perpendicular to the X axis and the Z axis), so that the area of the object can be scanned, and the XY plane is parallel to the surface of the object.

In an embodiment of the present invention, the electron beam source is configured to project the plurality of electron beams onto the respective plurality of sub-regions of the region of interest. By this, the area of interest that can be inspected or detected per unit time can be enlarged. In addition, in embodiments of the present invention, the electron beam source can be configured to generate electron beams with different energy levels. As will be explained in more detail below, depending on the applied energy level used for the electron beam, different parts or structures may be inspected, such as buried structures.

When this electron beam 120 is irradiated on the surface, interaction on the surface and interaction with the material below the surface will occur, causing both radiation and electrons to be emitted from the exposed surface. Generally, when the electron beam 120 interacts with the sample, the electrons constituting the beam will be scattered and absorbed in the tear-like volume (referred to as the interaction volume) to lose energy. The energy exchange between the electron beam and the sample will usually produce a combination of the following: -The reflection of high-energy electrons by elastic scattering,-the emission of secondary electrons by inelastic scattering,-the emission of electrons reflected or backscattered from the interaction volume by interacting with the elastic scattering of the sample,-X Ray emission, and-for example, emission of electromagnetic radiation in the range from deep UV to IR.

Electromagnetic radiation emits light, commonly known as cathodoluminescence or CL-light. In FIG. 2, arrow 140 indicates light that emits light through the emitting cathode.

In an embodiment of the present invention, the detection tool 100 further includes a detector 150 for detecting such cathodoluminescent light 140 emitted by the sample. In the embodiment as shown, the inspection tool 100 includes a reflector 160, such as an elliptical or parabolic reflector, to redirect the CL-light 140 toward the detector 150, as indicated by arrow 142. In the embodiment as shown, the reflector 160 is provided with an aperture 170 through which the electron beam 120 can be directed toward the object 130.

The detector 150 applied in the detection tool 100 according to the present invention may be formed, for example, as a CCD array, such as a two-dimensional CCD array, a hyperspectral sensor, or a spectrometer. In one embodiment of the present invention, the detection tool further includes a control unit 170 or a processing unit for processing the CL-light 140, 142 detected by the detector 150, for example, including a microprocessor, a computer or the like . In an embodiment, the control unit 170 includes an input terminal 172 for receiving a signal 152 from the detector 150. The signal 152 represents the detected CL-light 142 emitted by the object 130.

In an embodiment, the control unit may additionally have an output terminal 174 for outputting a control signal 112 that is used to control the electron beam source 110. In an embodiment, the control unit 170 may control the electron beam source 110 to project the electron beam 120 onto the region of interest of the object to be inspected, such as a semiconductor substrate.

In an embodiment, the control unit 170 may be configured to control the electron beam source 110 to scan the region of interest.

During this scan of the area of interest of the object, the detector may receive CL-light 142 from different parts of the area of interest. As an example, the applied electron beam may, for example, have a cross section with a diameter of 1 to 4 nanometers, and the area of interest is 100 nanometers x 100 nanometers. Thus, when the area of interest has been scanned, the response to the electron beam across the area of interest can be captured by the CL-light detector 150.

In an embodiment, an electron beam with a cross-section that substantially matches or exceeds the area of interest may also be applied. In this embodiment, the detector may, for example, be configured to capture an image of the entire area of interest. This detector may, for example, comprise a two-dimensional fiber array for capturing the emitted CL-light from a plurality of different positions on the area of interest. In an embodiment, the region of interest may include, for example, a buried structure below the surface of the region of interest. This buried structure may be, for example, an alignment mark.

In an embodiment, the control unit 170 applied in the detection tool 100 according to the present invention may be configured to determine the spectrum of CL-light received by the detector 150.

FIG. 3 schematically shows a spectrum 200 indicating the intensity I of received CL-light as a function of wavelength λ.

In general, the spectrum of the received CL-light may depend on various parameters. As will be understood, the frequency spectrum may depend on the material detected by the electron beam. In the case of a semiconductor substrate, the inspected area of interest may include a structure that forms part of an integrated circuit of a semiconductor device. These structures or devices will usually contain different materials, such as different semiconductor materials with different dopant materials or different dopant concentrations. Each of these materials can cause the generation of specific CL-lights with a specific spectrum. Under the condition that the interaction volume will cover different materials or structures, since CL-light is The volume below the surface is generated in a volume called the interaction volume, so the received CL-light can originate from a combination of different materials.

As will be explained in more detail below, by changing the energy of the electron beam, it is possible to change the depth of the detected volume and in particular the detected volume (i.e. the interaction volume), thereby enabling access to buried materials and structures and Enables the generation of 3D mapping.

FIG. 4 highly schematically shows a cross-sectional view of a semiconductor structure 400 including multiple layers and different materials. The structure 400 as shown schematically in FIG. 4 includes a bottom layer 402 of a first material, and three vertically extending structures 404 of a second material are on top of the bottom layer 402, adjacent to the gap between the structures 402 The structure 406 of the third material is ground filled, and the structures 404 and 406 are covered by the top layer 408 of the fourth material. FIG. 4 further schematically shows the electron beam 410 irradiated on the top surface 412 of the structure 400. The interaction volume of the electron beam 410 is indicated by the dotted line 414, that is, the volume in which CL-light can be generated due to the applied electron beam. It may be noted that although the electron beam may only have a diameter of a few nanometers, the interaction volume will generally have a larger diameter, for example 10 to 20 nanometers. Figure 4 further illustrates the scanning of the electron beam (indicated by arrow 420) towards the right, thereby moving the interaction volume 414 across the structures 404 and 406. During this scan, the interaction volume 414 will cover various materials of the structure. Therefore, during this scanning movement, there will be changes in the CL-light spectrum; based on these changes, it can be inferred that different materials or structures exist below the surface 412. In this regard, it can be noted that the generated CL-light is usually strongly related to the material. It can also be pointed out that due to the quantum effect that can determine the CL image resolution, such as the quantum limitation of excitons, the generated CL-light also depends on the size of the illuminated object or sample. Normally, silicon has an exciton radius of about 10 nanometers, but due to geometric constraints, excitons cannot be diffused further and CL is generated in the tested nanostructure. Due to this quantum limitation, an improved resolution is obtained. Generally, CL measurements will have a resolution of about 100 nanometers to 1 micrometer. Attributable to quantum limit The resolution can be changed from 5 to 10 nanometers.

Regarding the interaction volume 414 schematically indicated in FIG. 4, it is further worth mentioning that, among other things, the height or depth 430 of the interaction volume 414 will also depend on the energy level of the applied electron beam 410. As those skilled in the art will understand, the electron beam 410 will not be able to penetrate the structure 400 at a relatively low energy level of electrons. In this situation, the interaction may be limited to the material at or near the surface 412 (ie, material 408).

When an electron beam 410 with a relatively high energy level is used to scan the surface 412, the interaction volume will extend deeper into the structure 400 based on the observed changes in the CL-light spectrum observed during the scan, resulting in detection. Test different materials and structures.

Therefore, by scanning the area of interest with electron beams having different intensity or energy levels, the positions of various structures and/or the thickness of different material layers can be known.

In addition, it can be mentioned that the location where the spectrum change is detected can be used to obtain the geometric characteristics of the inspected structure. This situation is schematically illustrated in FIG. 5.

FIG. 5 highly schematically depicts a cross-sectional view of a region of interest 500 that includes a buried structure 510 provided on a layer 502, which layer is made of a first material, for example. The embedded structure 510 includes: a vertically extending structure 510.1 made of another second material; and an enclosed structure 510.2 made of a third material and surrounding the side surface and top surface of the structure 510.1. The structure 510 is further embedded, enclosed or covered by a layer 508 of yet another material. In the case where the electron beam 515 with the interaction volume 514 is used to scan the surface 512 of the region of interest in the direction as indicated by arrow 520 as indicated, some changes in the spectrum of the emitted CL-light can be observed. In detail, under the condition that the electron beam 515 starts to move along the X axis from the position as shown, it can be expected that the frequency spectrum remains substantially constant with the first frequency spectrum until the electron beam 515 reaches the interaction volume where it will start to enclose Up to the position where the structure 510.2 interacts (along the X axis). As the electron beam 515 moves further to the right, the frequency spectrum will gradually change, will remain constant with the second frequency spectrum within one of the positioning shifts along the X axis, and will then gradually change again toward the first frequency spectrum.

This transition is shown schematically in Figure 6. FIG. 6 schematically shows the spectrum FS observed when the electron beam 515 is scanned across the region of interest, that is, in the X direction as indicated in FIG. 5. As can be seen, from the beginning of the frequency spectrum FS1, the frequency spectrum will start to change towards the second frequency spectrum FS2 at a certain moment, this second frequency spectrum may remain constant and then will gradually change again towards the first frequency spectrum FS1. Since the position of the transition can be related to the interaction volume of the electron beam (the electron beam gradually changes from the interaction with one material such as the material of the layer 508 to the interaction with another material such as the material of the enclosure structure 510.2), Based on the position of the transformation along the X axis, it may be possible to determine or estimate the width Wd of the material having the second spectrum FS2.

In a similar manner, it is expected that when a stronger electron beam is applied, ie an electron beam with an interaction volume deeper into the region of interest, a transition to the third spectrum can occur, which means that it will enable the structure to be evaluated in the X direction The material of the structure 510.1 with a width of 510.1. Therefore, in the case of using the inspection tool according to the present invention, the material or chemical properties and geometric properties of the embedded structure can be evaluated.

As an alternative to determining the geometric properties of the buried structure by evaluating the observed changes in the frequency spectrum, it is also conceivable to use the emitted CL-light to generate an image of the region of interest and evaluate any geometric properties based on the image. This image can contain areas with different intensities or colors, where the contours or boundaries can be used to evaluate the geometric properties of the structure. It may be worth mentioning that such boundaries between the two areas may be slightly blurred. This can be understood as the reason for the fact that the detection of materials actually takes place in the interaction volume, thus causing a gradual transition between materials or structures. However, it should be noted that the aforementioned quantum effect can counteract this boundary blur and produce a clearer transition.

7 schematically shows a possible image 700 of the buried structure of FIG. 5, wherein the image reveals two different regions: a region 710 in which the interaction volume of the electron beam only interacts with the material of layer 508 of FIG. 5; and A zone 720 in which the interaction zone also interacts with the enclosure structure 510.2. FIG. 8 schematically shows an image 800 of the same area of interest, but the area of interest has an interaction volume that also penetrates the structure 510.1. In the image 800, four different regions can be identified: a region 810 in which the interaction volume of the electron beam only interacts with the material of the layer 508 of FIG. 5; a region 820 in which the interaction region interacts with the layer 508 and the enclosure structure 510.2 interaction; a zone 830 where the interaction zone interacts with the layer 508, the structure 510.1 and the enclosed structure 510.2; and a zone 840 where the interaction zone interacts with the layer 508 and the structure 510.1. After reviewing the image, it can be noted, for example, that the structure 510.1 extends longer than the enclosed structure 510.2 in the Y direction. Based on images and, for example, in combination with a priori known design data, it can be recognized, for example, that the structure 510.1 can be, for example, a fin of a fin FET and the enclosed structure 510.2 can be, for example, a gate electrode that surrounds the fin of a fin FET.

In addition to evaluating the material or chemical properties of different regions or structures that interact with the interaction volume of the applied electron beam, any irregularities in the structure can also be identified. In order to operate properly, there are different requirements for different materials or structures that form semiconductor devices. These requirements include materials or structures with appropriate material properties and appropriate sizes, but different structures also need to be in proper positions relative to each other. In the case of using the inspection tool according to the invention, it can also be evaluated whether different buried structures or structural components are configured as expected with respect to each other. With reference to the structure shown in FIG. 5, it may be necessary, for example, that the gate electrode of the enclosed structure 510.2 is positioned symmetrically above the fin structure of the structure 510.1. Based on the captured CL-light image, such as image 800 of FIG. 8, it can be evaluated whether this symmetry exists. In the situation where the captured CL-light image above the area of interest looks like the image 900 in FIG. 9, it can be estimated that The gate electrode of the structure 510.2 shown in FIG. 5 is not symmetrically arranged around the fin FET which is the structure 510.1 shown in FIG. 5. This asymmetry can lead to sub-optimal operation of the fin FET.

Thus, in one embodiment of the invention, the information obtained—material properties or properties or geometric properties or both, can be used to evaluate the functionality of the manufactured semiconductor device. It should be noted that in the embodiment, the information derived from the operation of the inspection tool can also be combined with the information from other sources to obtain an evaluation of the functionality of the semiconductor device. In detail, the electrical properties of semiconductor devices can be evaluated. In detail, the inspection tool according to the present invention can be used to spatially evaluate the homogeneity and uniformity of such parameters.

Another example of the evaluation of the proper relative position of a structure that can be determined using the present invention is the evaluation of overlapping pairs. Generally speaking, stacking refers to a method of aligning two consecutive layers formed on a semiconductor substrate. To evaluate this alignment, the first structure may be formed in the bottom layer, for example, during the exposure of the bottom layer, and the second structure may be formed in the top layer, for example, during the exposure of the top layer. The combination of the first and second structures may be referred to as overlay marks, for example. FIG. 10 schematically shows a cross-sectional view of this stack of indicia 1000, which shows a bottom patterned layer 1010 including the first structure 1012 and a top patterned layer 1020 including the second structure 1022, the bottom layer 1010 is configured at On the layer 1005 of the substrate, and the top layer 1020 is covered by a layer 1030 such as a resist layer. By scanning the surface 1012 of the region of interest that includes overlay marks (schematically indicated by electron beam 1015, interaction volume 1014, and direction 1016), overlay marks can be identified and evaluated in a similar manner as discussed above The embedded structure. In detail, the proper geometric structure of the first and second structures of the overlay mark and the relative position of the structure in the horizontal plane can be evaluated, thereby assessing the overlay error. As will be further explained, the detection tool according to the invention may also be equipped with a number of different sensors, such as sensors for detecting backscattered electrons or secondary electrons

In one embodiment of the invention, the detection tool according to the invention is configured to Evaluate the geometric properties of embedded structures. As an example of this geometric property, the location of the embedded structure can be mentioned. According to the present invention, the geometric properties are evaluated based on the light emitted by the received cathode light emitted during scanning the area of interest on the sample or exposing the area of interest to the electron beam.

In one embodiment of the invention, the determination of the geometric characteristics of the buried structure can be facilitated by introducing strain into the sample. According to an embodiment of the invention, this can be achieved by introducing sound waves into the sample. Due to the introduction of this sound wave, the sample will experience stress or strain. In the case where the sample contains an embedded structure with different physical or mechanical properties than its surroundings, a non-uniform strain distribution may appear in the sample. This strain or stress distribution can be detected by the detection tool according to the present invention, because when an object or structure is subjected to stress, the CL-light emitted by the object or structure in response to the application of an electron beam can vary. In one embodiment of the invention, this feature is utilized. In detail, in the present invention, the CL-light captured by the detector of the inspection tool is used to determine the stress distribution across the area of interest and the surface below the area of interest. By scanning the area of interest and observing the generated CL-light, changes in the observed spectrum can indicate the mechanical stresses that occur in the observed material (ie, the material present in the interaction volume). According to an embodiment of the present invention, the detected CL-light can be used to determine the stress or stress distribution in the volume below the surface of the region of interest.

FIG. 11 schematically illustrates the shift of the CL-optical spectrum due to the occurrence of stress in the material. In detail, FIG. 11 schematically shows the CL-light spectrum for a specific material under nominal conditions (curve 600) and when subjected to a certain stress level (curve 610). In the embodiment as shown, the stress induces a shift in the spectrum. Thus, when using electron beams to scan surface areas, such as areas 412, 512, or 1012 of the area of interest 400, 500, or 1000, shifts or generally changes in the CL-light spectrum can be observed, where such changes can be Associated with certain stress levels in the material.

With the help of experiments, the influence of a certain amount of stress on the transmitted CL-spectrum can be determined for various types of materials, and stored in a database, for example. In one embodiment of the invention, the control unit of the inspection tool, such as the control unit 170 shown in FIG. 2, can be connected to this database. It can be further pointed out that this database can be further used to distinguish between stress-induced spectrum changes and changes from one material or structure to another or changes caused by other stress sources. As indicated above, by adjusting the energy of the applied electron beam, the volume under the surface of the detected region of interest can be adjusted, that is, the interaction volume in which CL-light is generated. In particular, the use of relatively low energy electron beams will cause CL-light to be generated at or near the surface of the area of interest, while the application of relatively high energy electron beams will cause the volume of CL-light below the surface of the area of interest ( This is the interaction volume).

In one embodiment of the invention, acoustic waves can be introduced into the sample by means of a pulsed beam. FIG. 12 schematically illustrates an embodiment of a detection tool 1200 according to the present invention, in which this sound wave or ultrasonic wave can be generated. The detection tool 1200 includes an electron beam source 110 configured to project the electron beam 120 onto the region of interest of the sample 1230. In the embodiment as shown, the sample 1230 includes a plurality of stacked layers, where one of the layers configured below the surface 1232 includes a structure 1240, such as a grating or a mark. In the embodiment as shown, the detection tool 1200 further includes a detector 150 for detecting the cathodoluminescent light emitted by the sample indicated by arrow 140. In the embodiment as shown, the inspection tool 100 includes a reflector 160, such as an elliptical or parabolic reflector, to redirect the CL-light 140 toward the detector 150, as indicated by arrow 142. In the embodiment as shown, the reflector 160 is provided with an aperture 170 through which the electron beam 120 can be directed toward the sample 1230. FIG. 12 further schematically shows the light beam 1250 that can be focused onto the sample 1230 by the reflector 160. In one embodiment, the light beam 1250 may be, for example, a laser beam that generates short laser pulses. This laser beam 1250 can also be referred to as being used for pumps for example- The probe is aimed at the pump beam in progress. Due to the applied light beam 1250, acoustic waves 1260 can be generated in the sample 1230. In the embodiment as shown, the laser beam 1250 thus serves as an acoustic wave generator for generating acoustic waves 1260 in the region of interest of the sample 1230. This sound wave will interact with the buried structure 1240. Due to this interaction, stress or strain distribution will be generated in the area of interest. In detail, the acoustic wave 1260 can cause a strain distribution near the buried structure, where the strain distribution can extend to the surface 1232 of the sample 1230. Thus, due to the interaction of the acoustic wave 1260 with the buried structure, a stress or strain distribution may appear at or near the surface 1232 of the area of interest. In the embodiment as shown, the resulting stress or strain distribution is schematically indicated by line segment 1270. Since this strain distribution 1270 at or near the surface 1232 is caused by the interaction of the buried structure 1240 and the acoustic wave 1260, the strain distribution 1270 can represent the buried structure 1240, that is, it provides space for the buried structure 1240 Or geometric information. In the case of using the inspection tool 1200 as discussed above, this strain distribution 1270 may be determined based on the received CL-light during scanning of the sample 1230. Since the interaction between the buried structure 1240 and the acoustic wave 1260 can cause strain distribution at or near the surface 1232, the electron beam 120 is not required to be detected deep into the sample 1230, that is, the interaction volume of the electron beam 120 is not required Interact with the buried structure 1240 itself, but may be limited to interacting with only the upper portion or layer of the sample 1230, for example. Thus, a relatively low energy electron beam 120 can be applied.

Regarding the generation of sound waves in sample 1230, it can be pointed out that alternative methods for generating this sound wave can also be considered.

As an alternative to using a beam such as a pulsed laser beam, mention may be made of using an acoustic converter, such as a piezoelectric converter. This converter may, for example, be configured on an object table, such as object table 132 as shown in FIG. 2, on which sample 1230 is mounted.

Therefore, in one embodiment of the present invention, a detection tool is provided, which includes -An object table, such as a substrate table, which is used to hold the object to be inspected;-an electron beam source, which is configured to project the electron beam onto an area of interest of the object, where the area of interest includes an embedded type such as a grating Structure;-Acoustic wave generator, which is configured to generate acoustic waves in the region of interest, thereby generating strain distribution in the region of interest;-Cathodoluminescence detector, which is configured to when the strain distribution exists in the region of interest Detecting the cathodoluminescence light emitted from the area of interest when in the area;-the control unit, which is configured to:-receive a signal representing the light detected by the cathodoluminescence;-determine the embedded structure based on the signal characteristic.

In one embodiment, the inspection tool according to the present invention is used to determine the position of the embedded structure on the semiconductor substrate. In this embodiment, inspection tools can be used to determine the location of alignment marks such as buried structures. In this embodiment, the inspection tool may also be referred to as an alignment tool, which may, for example, be incorporated in a lithography apparatus and configured to determine a plurality of alignments before the substrate is subjected to a patterned radiation beam during the exposure process Mark the location on the substrate.

In one embodiment of the invention, an applied electron beam may also be applied that may have a cross-section that substantially matches or exceeds the area of interest. In this embodiment, the detector may, for example, be configured to capture an image of the entire area of interest. In an embodiment, the region of interest may include, for example, a buried structure below the surface of the region of interest. This buried structure may be, for example, an alignment mark. By applying an electron beam whose cross-section matches or exceeds the size of the embedded structure, an image of the entire embedded structure can be generated. This image can then, for example, cover an area of about 80 microns x 40 microns or 50 microns x 50 microns or greater; the applied electron beam can, for example, have a field of view having a diameter of 100 microns. In this embodiment, the entire area of interest can be exposed to wide unshaped electrons Beam, thereby causing CL-light to be emitted from the entire exposed area of interest. With the aid of suitable optics, an image that emits CL-light can be generated and directed to a detector, for example.

In one embodiment, the generated image can be imaged on the reference grating. In this embodiment, the multimode fiber can collect the light transmitted through the reference grating and direct it to the detector of the detection tool, such as a spectrometer. During the scanning of the electron beam across the region of interest, the region of interest contains the buried grating, the measured CL-light can then oscillate between the following two different CL-spectrums: the frequency corresponding to the spectrum of the buried grating One spectrum, one corresponding to the material in the groove between the gratings. In this regard, reference may be made to FIG. 4, for example, where the structure 404 may, for example, represent a buried grating, and the trenches between the gratings may contain structures 406 of different materials.

In an alternative embodiment, the CL-light emitted image may be supplied to an optical fiber array, such as a two-dimensional optical fiber array, where each fiber in the optical fiber array may be connected to a spectrometer. In this embodiment, each fiber and corresponding spectrometer will collect CL-light from different locations on the sample; each fiber will thus obtain CL-light from a specific sub-region of the region of interest. With this configuration, it is possible to use a wide, unshaped electron beam to illuminate or expose the entire area of interest and generate an image, such as the characteristics of the embedded structure of the grating, which can be derived from the image. Compared with an embodiment using a reference grating, this embodiment can be made independent of the spacing, which refers to the distance between grating structures (such as the structure 404 of FIG. 4).

In one embodiment of the invention, for example, a wide electron beam that spans the region of interest including the embedded grating can be used to determine the position of the embedded grating. This embodiment of the inspection tool can therefore also be used as an alignment tool in lithographic equipment.

In one embodiment, the inspection tool according to the present invention is configured to evaluate the characteristics, material properties or geometric characteristics of the buried structure, or to evaluate the functionality for a plurality of such structures distributed across the semiconductor substrate. By this, any change of these parameters can be detected at the initial stage and It can be used to adjust various procedures that the substrate is subjected to. In one embodiment of the present invention, the detection tool according to the present invention is applied as an in-line tool configured in a lithography apparatus. In this embodiment, the substrate stage used during the evaluation of the stress distribution by the inspection tool is also used during the subsequent exposure of the substrate to the patterned radiation beam. Thus, in one embodiment, the present invention provides a lithography system including a lithography apparatus and an inspection tool, wherein the lithography apparatus includes a stage apparatus configured to position the substrate stage within the operating range of the electron beam In order to scan the substrate with the electron beam of the electron beam source used for detection, and position the substrate table in the operating range of the projection system, so as to impart the patterned radiation beam generated by the projection system to the substrate. In this embodiment, the lithography system can be configured to:-detect the substrate when the substrate is clamped on the substrate table positioned by the stage device of the lithography equipment;-determine the area of interest on the substrate Characteristics of the embedded structure;-The substrate is positioned relative to the patterned radiation beam by the stage equipment when the substrate is on the substrate table, wherein the procedure of positioning the substrate table or generating the patterned radiation beam can be based on the determined characteristics .

In the case where the detection tool is incorporated in the lithography apparatus, it may be provided, for example, in a vacuum chamber of the apparatus, for example, a dedicated vacuum chamber or a vacuum chamber already exists such as in an EUV lithography apparatus.

In this configuration, care should also be taken to ensure that the inspection tools, especially the electron beam source, are not affected by magnetic fields that can be generated by stage equipment or other possible sources such as actuators. To achieve this, electromagnetic shielding may be applied.

As an alternative to incorporating the inspection tool in the lithography apparatus, the lithography system according to the present invention may include the lithography apparatus, the inspection tool according to the present invention, and for self-inspection of the substrate Transfer the test tool to the transfer system of the lithography equipment. In this embodiment, the transfer system can transfer the substrate when the substrate is clamped onto the substrate table, that is, the substrate and the substrate table are collectively transferred from the inspection tool to the lithography apparatus in the clamped state, for example.

As another alternative, the inspection tool according to the present invention may be a stand-alone tool having its own substrate stage and an interface for transferring the substrate to and from the tool.

In the above, it has been discussed that changes in CL-light, especially changes in the spectrum of captured CL-light, can be used to identify different structures and materials and various characteristics of such materials or structures. In this regard, it is worth pointing out that in addition to the spectrum, other characteristics of CL-light can also be used to evaluate the state of the substrate or to detect the substrate. In addition to observing the spectrum of the received CL-light or as an alternative, other characteristics of the received CL-light can also be considered in order to evaluate the transition between structures or materials or to evaluate various characteristics of such materials or structures. Examples of such other characteristics may be, for example, the polarization characteristics of CL-light, the orientation of received CL-light, or the transient characteristics of CL-light. In a similar way to evaluating the CL-light spectrum and its changes across the area of interest, the evaluation of the polarization characteristics of the received CL-light can also be used to determine the occurrence of changes in the material properties including stress. Similarly, orientation, especially angular orientation through received CL-light, can also be used to evaluate the transition between structures or materials or to characterize such structures or materials. It should be noted that the angular orientation of CL-light can be determined or characterized, for example, by the position of the light impinging on the detector. Referring to FIG. 2, those skilled in the art should understand that the angular orientation of CL-light indicated by arrow 140 affects the position of light irradiating on reflector 160 and therefore also the position of CL-light irradiation detector 150. Another characteristic of CL-light is any transient that can be perceived in the captured light, that is, any change over time.

The detection tool according to the present invention is configured to detect CL-light emitted by an area of interest (eg, a portion of a semiconductor substrate). Inspection of substrate or part based on CL-light detection The measurement can be performed faster than detection based on backscattered electrons. Generally, a relatively large number of photons are generated during the exposure of the substrate with an electron beam, so that the yield or yield of this detection method is relatively high compared to, for example, the detection of backscattered electrons. However, it can be pointed out that the resolution of the detector for detecting backscattered electrons can be greater than the detector for detecting CL-light.

In an embodiment of the invention, the detection tool may be equipped with different types of detectors, including, for example, a backscatter (BS) electron detector or a secondary electron (SE) detector. In this embodiment, the BS-detector or SE-detector can be used for calibration purposes, for example. As an example, a BS-detector or SE-detector can be used, for example, to calibrate a CL-light detector.

In one embodiment of the invention, the data obtained from the inspection tool can be combined with the data obtained from other tools such as other inspection tools or metrology tools, wherein the combined set of data is used to determine the functional characteristics of the manufactured semiconductor device Or device functionality. As an example, the data of the inspection tool according to the invention can be combined with data from scanning electron microscope (SEM) or from optical critical dimension (OCD) metrology, for example, or can be combined with design parameters rather than other measurements. In the case of using data obtained from the inspection tool according to the present invention or combined data, device functionality such as device resistance, layer thickness, dopant concentration, threshold voltage, and other functionalities can be determined.

Using this information as a feedback to the lithography equipment, for example, to control the exposure process performed enables both device performance and equipment yield to be improved. The obtained information can also be used in machine learning techniques to, for example, generate empirical models that link the determined CL-light characteristics to device characteristics such as overlay characteristics.

In the above, the use of the inspection tool according to the present invention has been described for the purpose of inspecting a semiconductor substrate. However, it can be pointed out that it can also be used to detect EUV blanks or EUV masks, for example. EUV blanks or quartz substrates used to manufacture EUV reticle or patterned devices The board may contain defects. It can be pointed out, for example, that the yield of manufacturing processes for such sufficiently defect-free EUV blanks is relatively low. The detection of this EUV blank before the application of, for example, a multilayer stack of Mo-Si can cause the detection of defective blanks in the initial stage. The detection tool according to the invention can realize such detection. In detail, the CL-light generated when the surface of the EUV blank is exposed to an electron beam is strongly affected by the surface morphology. In this way, different types of defects can also be distinguished. For example, defects in quartz on the surface can produce recombination centers, where the emission of CL-light will be high. Thus, the presence of defects will be highlighted and the location can be determined. Crystallization defects can also be detected in a similar manner. Therefore, in the case of using the inspection tool according to the present invention, the surface of the EUV blank can be imaged at a relatively high speed with a resolution of <10 nm.

In addition, the inspection tool according to the present invention can also be applied to inspect a multi-layer mask or a reduced-magnification mask, such as a stacked mask with Mo and Si layers.

Therefore, in one embodiment of the present invention, there is provided an inspection tool for detecting EUV blanks or EUV masks, the inspection tool comprising-an object table configured to hold an EUV blank or EUV mask;- Electron beam source, which is configured to project the electron beam onto the area of interest of the EUV blank or EUV mask;-Cathodoluminescence detector, which is configured to detect the cathodoluminescence emitted from the area of interest Light;-control unit, which is configured to:-control the electron beam source to project the electron beam onto the area of interest;-receive a signal representing the light detected by the cathode;-determine the area of interest based on the signal The characteristics or locations of the above defects.

This tool can be configured to perform the following detection methods: A detection method comprising the following steps:-providing an EUV blank or EUV mask with an area of interest;-scanning the area of interest using an electron beam;-capturing CL-light emitted from the area of interest;-based on the captured Optically determine the characteristics or locations of defects on the area of interest.

The following items can be used to further describe the embodiment:

1. An inspection tool for inspecting a semiconductor substrate, the inspection tool comprising-a substrate stage configured to hold the substrate;-an electron beam source configured to project an electron beam onto the substrate On one of the regions of interest, the region of interest includes an embedded structure;-a cathode luminescence detector configured to detect the light emitted by the cathode from the embedded structure;-a control unit , Which is configured to:-receive a signal representing the detected light emitted by the cathode;-determine a characteristic of the embedded structure based on the signal.

2. The inspection tool of item 1, wherein the control unit is further configured to:-control the electron beam source to project the electron beam onto the area of interest;

3. The inspection tool of item 1 or 2, wherein the characteristic is at least a part of the material characteristic of the embedded structure.

4. The inspection tool of item 3, wherein the material characteristic is an electrical characteristic or a chemical characteristic.

5. The detection tool according to clause 3 or 4, wherein the control unit is configured to determine a spectrum of the detected light emitted by the cathode.

6. The inspection tool of clause 5, wherein the control unit is configured to determine the material properties based on the frequency spectrum.

7. The inspection tool of clause 5 or 6, wherein the control unit is further configured to receive a signal representing a geometric characteristic of the structure, and wherein the control unit is configured to be based on the material characteristic and the geometric characteristic Evaluate the functionality of semiconductor devices.

8. The inspection tool of item 1 or 2, wherein the characteristic is a geometric characteristic of the structure.

9. The inspection tool of clause 8, wherein the geometric characteristics include position information of the structure.

10. The inspection tool of clause 9, wherein the position information includes a position of the structure relative to another structure.

11. The inspection tool of clause 10, wherein the structure and the additional structure are positioned in different layers of the semiconductor substrate.

12. The inspection tool of clause 11, wherein the structure and the additional structure form a stack of pairs of marks.

13. The inspection tool of any one of clauses 8 to 12, wherein the signal represents an image of the embedded structure, and wherein the control unit is configured to determine the embedded structure based on image processing of the image The geometric characteristics.

14. The inspection tool according to any one of the preceding clauses, wherein the control unit includes an output terminal for outputting a signal representing the determined characteristic.

15. The inspection tool according to any one of the preceding clauses, wherein the region of interest includes a plurality of embedded structures distributed across the substrate, and wherein the control unit is further configured to target the plurality of embedded types The structure determines that one of the characteristics changes.

16. The inspection tool of clause 15, wherein the control unit is configured to output a signal representing the change in the characteristic.

17. The inspection tool according to any one of the preceding clauses, wherein the electron beam source is configured to project a plurality of electron beams onto respective plurality of sub-regions of the region of interest.

18. The inspection tool of any of the preceding clauses, wherein the electron beam source is configured to generate electron beams with a different energy level.

19. The inspection tool according to item 18, wherein the control unit is configured to:-control the electron beam source to project a plurality of electron beams with different energy levels onto the region of interest;-receive to indicate that the Multiple signals of the light emitted by the cathode are detected;-based on the multiple signals, the characteristics of the embedded structure are determined.

20. The detection tool according to any of the preceding items, further comprising a backscatter (BS) electron detector configured to detect the emission from the area of interest Backscattered electrons.

21. The detection tool of clause 20, wherein the control unit is configured to:-receive a signal representing the detected backscattered electrons, and-based on the light representing the detected cathode light emission The signal and the signal representing the detected backscattered electrons determine the characteristic.

22. The detection tool according to any one of the preceding clauses, wherein the control unit is configured to:-determine an angular orientation, a polarization, or a transient state of the detected light emitted by the cathode.

23. The detection tool of clause 22, wherein the control unit is configured to:-determine the characteristic of the buried structure based on the angular orientation, the polarization, or the transient state of the detected cathodoluminescence light .

24. A lithography apparatus, comprising:-an illumination system configured to adjust a radiation beam; -A support member constructed to support a patterned device capable of imparting a pattern to the radiation beam in the cross-section of the radiation beam to form a patterned radiation beam;-a projection system whose warp Configured to project the patterned radiation beam onto a target portion of a substrate; wherein the device further includes a detection tool as described in any one of the preceding clauses and a stage equipment, the stage equipment is It is configured to position the substrate table so as to impart the patterned radiation beam to the substrate.

25. The lithography apparatus of clause 24, further comprising a stage control unit configured to control the stage equipment, the stage control unit configured to receive representations A signal of the characteristic of the embedded structure, and wherein the stage control unit is configured to control the stage equipment based on the characteristic.

26. The lithography apparatus of item 24 or 25, further comprising a projection control unit configured to control the projection system and the lighting system, the projection control unit configured to receive the embedded signal A signal of the characteristic of the structure, and wherein the projection control unit is configured to control the projection system and/or the illumination system based on the characteristic.

27. The lithography apparatus of any one of clauses 25 to 26, wherein the substrate table includes a clamping mechanism for clamping the substrate to the substrate table.

28. The lithography apparatus of any one of clauses 26 to 27, further comprising a vacuum chamber configured to enclose the electron beam source.

29. The lithography apparatus of item 28, wherein the vacuum chamber further encloses the projection system.

30. The lithography apparatus of any one of clauses 24 to 29, wherein the stage apparatus includes one or more electromagnetic motors, and wherein the lithography apparatus further includes a shielding member, the shielding member is It is configured to shield the electron beam source from the magnetic field of one of the stage devices.

31. A lithography system, comprising:-a detection tool as in any one of clauses 1 to 23, and-a lithography equipment, comprising:-an illumination system configured to adjust a radiation beam ;- A support, which is constructed to support a patterned device capable of imparting a pattern to the radiation beam in the cross-section of the radiation beam to form a patterned radiation beam;-A projection system, which Configured to project the patterned radiation beam onto a target portion of a substrate;-a stage device configured to position the substrate table to impart the patterned radiation beam to the substrate.

32. A detection method comprising the following steps:-providing a substrate having an area of interest, the area of interest including a buried structure;-scanning the area of interest using an electron beam;-capturing from the site Focus on the CL-light emitted by the area;-Determine one of the characteristics of the buried structure.

33. The detection method of clause 32, further comprising:-generating an image of the embedded structure based on the captured CL-light; and-determining the characteristic of the embedded structure based on the generated image.

34. The detection method of clause 32 or 33, wherein the embedded structure includes a stack, the stack includes a first layer and a second layer, and the geometric attribute is the embedded structure in the first layer Of A relative position between a first portion and a second portion of the buried structure in the second layer.

35. A device manufacturing method comprising projecting a patterned radiation beam onto a substrate, wherein the step of projecting the patterned radiation beam onto the substrate is detected in any one of items 32 to 34 Before the method.

36. An inspection tool for inspecting a semiconductor substrate, the inspection tool comprising-a substrate stage configured to hold the substrate;-an electron beam source configured to project an electron beam onto the substrate On a region of interest, the region of interest includes an embedded structure;-an acoustic wave generator configured to generate an acoustic wave in the region of interest, thereby generating a strain in the region of interest Distribution;-a cathodoluminescence detector, which is configured to detect the cathodoluminescence light emitted from the area of interest when the strain distribution is present in the area of interest;-a control unit, which is configured To:-receive a signal representing the detected light emitted by the cathode;-determine a characteristic of the embedded structure based on the signal.

37. The inspection tool of clause 36, wherein the acoustic wave generator comprises a laser configured to generate a laser pulse for generating the acoustic wave in the area of interest.

38. The inspection tool of clause 36, wherein the acoustic wave generator includes an acoustic transducer for generating the acoustic wave in the area of interest.

39. The inspection tool of any one of clauses 36 to 38, wherein the embedded structure includes a grating and wherein the characteristic of the embedded structure includes a position of the grating.

40. The inspection tool according to any one of items 1 to 24 or 36 to 39, wherein the electron beam source is It is configured to project an electron beam onto the area of interest, and a cross-sectional area of the electron beam substantially spans the area of interest.

41. The detection tool of clause 40, wherein the cathodoluminescence detector includes an optical fiber array configured to receive the cathodoluminescence light emitted from the area of interest.

42. The inspection tool of clause 41, wherein the optical fiber array comprises a two-dimensional optical fiber array, and each optical fiber in the optical fiber array is configured to receive cathodoluminescence light emitted from a sub-region of the region of interest.

43. The detection tool of clause 41 or 42, wherein the cathodoluminescence detector further comprises a spectrometer array, each spectrometer in the spectrometer array being connected to a respective optical fiber in the optical fiber array.

44. The detection tool of clause 40, wherein the cathodoluminescence detector includes an optical fiber for receiving the cathodoluminescence light and providing the cathodoluminescence light to a spectrometer of the cathodoluminescence detector.

45. The inspection tool of item 44, further comprising a reference grating, which is used to give the cathode light.

46. The inspection tool of clause 45, wherein the cathodoluminescence light is imaged onto the reference grating, and wherein the cathodoluminescence light transmitted through the reference grating is provided to the spectrometer.

47. The inspection tool according to any one of clauses 36 to 39, wherein the strain distribution contains information about the embedded structure.

Although specific reference may be made herein to the use of lithographic devices in IC manufacturing, it should be understood that the lithographic devices described herein may have other applications, such as manufacturing integrated optical systems, guides for magnetic domain memories Introduce and detect patterns, flat panel displays, liquid crystal displays (LCD), thin film magnetic heads, etc. Those familiar with this technology should understand the content of these alternative applications In the background, any use of the terms "wafer" or "die" herein may be considered as synonymous with the more general terms "substrate" or "target portion", respectively. This article can be processed in, for example, automated photoresist coating and development systems (tools that typically apply a resist layer to the substrate and develop the exposed resist), metrology tools, and/or inspection tools before or after exposure The mentioned substrate. Where applicable, the disclosures in this article can be applied to these and other substrate processing tools. In addition, the substrate can be processed more than once, for example, to produce a multilayer IC, so that the term "substrate" as used herein may also refer to a substrate that already contains multiple processed layers.

Although the above may specifically refer to the use of embodiments of the present invention in the context of optical lithography, it should be understood that the present invention can be used in other applications (for example, embossing lithography), and where the context of the content permits Not limited to optical lithography. In imprint lithography, the topography in the patterned device defines the pattern created on the substrate. The configuration of the patterned device can be pressed into the resist layer supplied to the substrate, where the resist is cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterned device is removed from the resist, leaving a pattern therein.

The terms "radiation" and "beam" as used herein encompass all types of electromagnetic radiation, including ultraviolet (UV) radiation (eg, having a wavelength of about 365, 248, 193, 157, or 126 nanometers) and extreme ultraviolet (EUV) Radiation (for example with a wavelength in the range of 5 to 20 nanometers), and particle beams, such as ion beams or electron beams.

The term "lens" may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic, and electrostatic optical components, as the context permits.

Although specific embodiments of the invention have been described above, it should be understood that the invention may be practiced in other ways than those described. For example, the present invention can be used to In the form of the following: a computer program that contains one or more sequences of machine-readable instructions describing the method as disclosed above; or a data storage medium (such as semiconductor memory, magnetic disk, or optical disk) that stores this Computer program.

The above description is intended to be illustrative, not limiting. Therefore, it will be obvious to those skilled in the art that the described invention can be modified without departing from the scope of the patent application scope set forth below.

1000‧‧‧ Stacked pair of marks/area of interest

1005‧‧‧ storey

1010‧‧‧patterned bottom

1012‧‧‧First structure/surface/area

1014‧‧‧Interaction volume

1015‧‧‧ electron beam

1016‧‧‧ direction

1020‧‧‧Top patterned layer

1022‧‧‧Second structure

1030‧‧‧ storey

Claims (15)

An inspection tool for inspecting a semiconductor substrate, the inspection tool includes: a substrate stage configured to hold the substrate; an electron beam source configured to project an electron beam to one of the substrates On an area of interest, the area of interest includes a buried structure; a cathodoluminescence detector configured to detect the cathodoluminescence light emitted from the buried structure ( cathodoluminescent light); a control unit configured to: receive a signal representing the detected light emitted by the cathode; determine a characteristic of the embedded structure based on the signal. The inspection tool of claim 1, wherein the control unit is further configured to: control the electron beam source to project the electron beam onto the region of interest. The inspection tool according to claim 1 or 2, wherein the characteristic is at least a part of the material characteristic of the embedded structure. The testing tool according to claim 3, wherein the material property is an electrical property or a chemical property. The detection tool according to claim 3, wherein the control unit is configured to determine a spectrum of the detected light emitted by the cathode. The inspection tool of claim 5, wherein the control unit is configured to determine the material properties based on the frequency spectrum. The inspection tool of claim 5, wherein the control unit is further configured to receive a signal representing a geometric characteristic of the structure, and wherein the control unit is configured to evaluate the semiconductor device based on the material characteristic and the geometric characteristic Feature. The inspection tool according to claim 1 or 2, wherein the characteristic is a geometric characteristic of the structure. As in the inspection tool of claim 8, wherein the geometric characteristic includes the position information of the structure. The inspection tool of claim 9, wherein the position information includes a position of the structure relative to another structure. The inspection tool of claim 10, wherein the structure and the additional structure are positioned in different layers of the semiconductor substrate. The inspection tool of claim 8, wherein the signal represents an image of the embedded structure, and wherein the control unit is configured to determine the geometric characteristics of the embedded structure based on image processing of the image. The inspection tool of claim 1 or 2, wherein the electron beam source is configured to produce a Electron beams of the same energy level, and wherein the control unit is configured to: control the electron beam source to project a plurality of electron beams with different energy levels onto the region of interest; receiving indicates that the detected Multiple signals of the light emitted by the cathode; the characteristics of the embedded structure are determined based on the multiple signals. The detection tool of claim 1 or 2 further includes a back-scattering (BS) electron detector configured to detect the emission from the area of interest Backscattered electrons, and wherein the control unit is configured to: receive a signal representing the detected backscattered electrons, and based on the signal representing the detected light emitted by the cathode and represent the The signal after detecting backscattered electrons determines the characteristic. The detection tool according to claim 1 or 2, wherein the control unit is configured to: determine an angular orientation, a polarization, or a transient of the detected cathode light, and based on the The angle orientation, the polarization, or the transient state of the light emitted by the cathode is determined to determine the characteristic of the buried structure.

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