TW201837865A - Method for inspecting a substrate and computer readable medium having instructions stored thereon - Google Patents

Abstract

A method for inspecting a substrate is described. The method includes providing the substrate being a large area substrate in a vacuum chamber, wherein the substrate has a thin-film with a grain structure deposited on the substrate; generating a primary charged particle beam with an imaging charged particle beam microscope, wherein the primary charged particle beam impinges on the substrate in the vacuum chamber; and generating one or more images from signal particles released from the substrate upon impingement of the primary charged particle beam, wherein the one or more images are topographic images.

Description

Method of inspecting a substrate and computer readable medium having a plurality of instructions stored thereon

The disclosure relates to the detection of a low temperature polysilicon (LTPS) layer and a method of inspecting a substrate. More specifically, the embodiments described herein relate to a method of inspecting a substrate for display fabrication, and more particularly to a large area substrate for display fabrication.

In many applications, it is desirable to deposit a film on a substrate, such as on a glass substrate. Traditionally, substrates have been coated in chambers of different coating equipment. In some applications, the substrate is coated in a vacuum using a vapor deposition technique. In the past few years, the price of electronic devices, and in particular optoelectronic devices, has been greatly reduced. In addition, the pixel density in the display continues to increase. For thin film transistor (TFT) displays, high density TFT integration is required. However, even if the number of thin film transistors (TFTs) in the device is increased, the yield is increased as much as possible and the manufacturing cost is as low as possible.

One aspect of increasing the pixel density is the use of low temperature polysilicon-TFT (LTPS-TFT), which can be used, for example, in liquid crystal displays (LCDs) or active organic light emitting displays (AMOLED displays). In the fabrication of LTPS-TFTs, the gate electrode can be used as a mask for doping the active layer of the transistor with the source and drain contact regions. The quality of this self-aligned doping can determine the yield of the manufacturing process and, therefore, the process needs to be improved and controlled. However, other self-aligned doping applications other than the LTPS-TFT process can also benefit from an improved process.

For such processes, it is beneficial to monitor the quality of the substrate to inspect the substrate, which is the deposited layer, specifically a low temperature polysilicon (LTPS) layer. For example, for the display market, a glass substrate on which a layer of coating material is deposited is fabricated. Displays are typically fabricated on large area substrates and the size of the substrates continues to increase. In addition, displays such as TFT displays are also being continuously improved. For example, low temperature polysilicon (LTPS) is a development that can achieve low power consumption and improved backlight characteristics.

The inspection of the substrate can be performed by, for example, an optical system. However, the grain structure, grain size and grain morphology at the grain boundaries of low temperature polysilicon (LTPS) are particularly difficult to observe with optical systems because the grain size may be lower than the optical resolution, resulting in grain It is invisible to the optical system. Inspection of a small portion of the substrate has also been performed using a charged particle beam device in conjunction with surface etching. Surface etching can enhance the contrast of, for example, grain boundaries, but inevitably damages the glass substrate and is therefore inspected for the small portion of the substrate rather than the entirety of the substrate. Therefore, after the substrate is inspected, it is impossible to continue processing the substrate, for example, to check the influence of the grain structure on the final product.

Therefore, there is a need for an improved method for inspecting large area substrates due to, for example, the increasing demand for quality of displays on large area substrates.

Provided herein is a method of inspecting a substrate and an apparatus using the same. The aspects, advantages, and features of the present disclosure will be more clearly understood from the scope of the appended claims.

According to an embodiment, a method of inspecting a substrate is provided. The method comprises: providing a substrate to a vacuum chamber, wherein the substrate is a large area substrate, wherein the substrate has a film having a grain structure deposited on the substrate; and utilizing an imaged charged particle beam microscope to generate a main a charged particle beam, wherein a primary charged particle beam impinges on a substrate in a vacuum chamber; and one or more images are generated from signal particles released by the substrate upon impact of the primary charged particle beam, wherein the one or more images are Topographic images.

In some embodiments, some of the innovative methods described herein can be implemented in a computer readable medium. The computer readable medium has a plurality of instructions stored thereon, and when executed, causes a charged particle beam microscope to perform any of the methods of inspecting a substrate as described herein.

A plurality of embodiments are described in detail below with reference to the drawings, which illustrate one or more examples. The examples are intended to be illustrative and not limiting as to the disclosure. For example, features illustrated or described in one embodiment can be used in other embodiments or in combination with other embodiments to derive further embodiments. The disclosure includes the above adjustments and variations.

In the following description of the drawings, the same reference numerals refer to the same elements. Only the differences of the respective embodiments will be described. The structures in the drawings are not necessarily shown in actual true scale, but are used to better understand the embodiments.

The term "substrate" as used herein includes a non-flexible substrate such as a glass substrate or a glass plate; and a flexible substrate such as a web and a foil. The substrate may be a coated substrate in which one or more layers of material are coated or deposited on the substrate and are completed by, for example, a physical vapor deposition (PVD) process or a chemical vapor deposition (CVD) process.

The embodiments described herein relate to large area substrates, particularly large area substrates for the display market. According to some embodiments, the large area substrate or corresponding respective substrate support may have a size of at least 1 square meter. This size may range from about 1.375 square meters (1100 mm x 1250 mm - 5th generation) to about 9 square meters, more specifically from about 2 square meters to about 9 square meters or even up to 12 square meters. The substrate or substrate receiving region provided in accordance with the structures, devices, and methods of some embodiments described herein can be a large area substrate as described herein. For example, the large-area substrate or carrier may be the 5th generation (GEN 5), which corresponds to a substrate of about 1.375 square meters (1.1 meters x 1.25 meters); the 7.5th generation (GEN 7.5), which corresponds to A substrate of approximately 4.39 square meters (1.95 meters x 2.25 meters); 8.5th generation (GEN 8.5), which corresponds to a substrate of approximately 5.7 square meters (2.2 meters x 2.5 meters); or the 10th generation (GEN10), which corresponds to a substrate of about 9 square meters (2.88 meters x 3130 meters). Even higher orders, such as the 11th generation (GEN 11) and the 12th generation (GEN 12) and their corresponding substrate regions can be implemented in a similar manner.

Without limiting the scope of protection of the present application, in the following context, a charged particle beam device, such as a charged particle beam microscope or a component thereof, will be exemplarily referred to as a charged particle beam device, including secondary particles or Detection of backscattered particles, secondary particles or backscattered particles are, for example, electrons. Various embodiments may still be applied to devices and components for obtaining detection of corpuscles of sample images, such as secondary and/or backscattered charging in the form of electrons or ions, photons, X-rays, or other signals. particle. When a particle is referred to herein, a particle is understood to mean an optical signal, wherein the particles are photons and particles, and wherein the particles are ions, atoms, electrons or other particles. As discussed herein, the discussion and description of detection is exemplarily described for electrons in a scanning electron microscope. Other types of charged particles, such as positive ions, can be used in devices of a variety of different instruments.

According to some embodiments herein, which may be combined with other embodiments, a signal (charged particle) beam or a signal (charged particle) beamlet is referred to as a secondary and/or backscattered particle beam. Typically, the signal beam or secondary beam is generated by impinging on the sample via a primary beam or a primary beam. The primary charged particle beam or the predominantly charged particle beamlet is generated via a particle beam source and directed and deflected on the sample to be inspected or to be imaged.

FIG. 1 illustrates a charged particle beam device or a charged particle beam microscope 100. An electron beam (not shown) may be generated via electron beam source 112. Additional beam shaping means, such as suppressors, extractors and/or anodes, may be provided within the gun chamber 110. The beam can be aligned with a beam limiting aperture that is sized to shape the beam, i.e., block a portion of the beam. The electron beam source compartment includes a TFE emitter. The gun chamber can be evacuated to a pressure of 10 ^-8 mbar to 10 ^-9 mbar.

A condenser lens may be disposed in an additional vacuum chamber 120 of the beam column of the charged particle beam microscope 100. For example, the concentrator lens can include a pole piece 122 and a coil 124. Additional electro-optical elements 126 may be provided in additional vacuum chambers. The additional electro-optical element 126 may be selected from the group consisting of an astigmatism device, a correction element for chromatic aberration and/or spherical aberration, and an alignment for aligning the main charged particle beam with the optical axis of the objective lens 140. A group of polarizers.

The main electron beam can be focused on the substrate 10 through the objective lens 140. The substrate 10 is positioned at a substrate location on the substrate support 150. When the electron beam impinges on the substrate 10, the signal electrons are released from the substrate 10 and can be detected by the detector 139, which is, for example, secondary and/or backscattered electrons, and/or x-rays.

In some embodiments, corresponding to that depicted in FIG. 1, a concentrator lens 123 is provided. A two-stage deflection system (not shown) may be provided between the concentrator lens and, for example, the beam limiting aperture, for aligning the beam with the aperture, and the beam limiting aperture is, for example, a beam shaping aperture. (beam shaping aperture). As shown in Fig. 1, the objective lens 140 has a magnetic lens member having pole pieces 142 and 146 and having a coil 144. The objective lens focuses the main electron beam on the substrate 10. Further, an upper electrode 152 and a lower electrode 154 form an electrostatic lens component of the objective lens 140.

Additionally, a scan deflector assembly 170 can be provided. The scan deflector assembly 170 can be, for example, a magnetic component, but is preferably an electrostatic scan deflector assembly configured for high pixel rates. Scanning deflector assembly 170 can be a single stage component, as shown in FIG. Alternatively, a two-stage deflector assembly or even a three-stage deflector assembly can be provided for scanning. Each stage has a different position along the optical axis.

The lower electrode 154 is connected to a voltage source (not shown). The lower electrode serves as the decelerating electrode of the immersed lens member of the objective lens, the immersed lens member, that is, the retarding field lens member, and the lower electrode is usually at a potential which causes the charged particles on the substrate to have a wavelength equal to or less than 2 keV. The landing energy is, for example, 500 V or 1 keV. As shown in FIG. 1, according to some embodiments, the substrate support 150 can be set to a ground potential. Thus, the lower electrode 154 can have a positive voltage of about 200 V to 1 kV, for example to generate a landing energy of 200 eV to 1 keV.

According to some embodiments herein, which may be combined with other embodiments, the primary charged particle beam may be decelerated in the vicinity of the substrate 10, such as within an objective lens, behind an objective lens, or a combination thereof. Deceleration can be provided separately via the lower electrode 154, that is, the decelerating electric field lens. Deceleration can be provided via an electrostatic lens component such as an objective lens. For example, further or alternatively, a deceleration bias voltage can be applied to the substrate 10 and/or the substrate support to provide a decelerating electric field lens component in accordance with some embodiments described herein. The objective lens may be an electrostatic-magnetic composite lens having, for example, an axial gap or a radial gap, or the objective lens may be an electrostatically decelerating electric field lens.

According to some embodiments herein, which may be combined with other embodiments, the distance between the lower portion or edge of the objective lens and the substrate or substrate support may be from 1 millimeter (mm) to 3 millimeters, for example 1.5 millimeters, while the lower portion of the objective lens or The edge is, for example, the lower electrode 154. The resolution of the image measured on the large-area substrate is less than 15 nm, for example, 3 nm to 12 nm, for example, about 10 nm, and the large-area substrate has, for example, an area equal to or greater than 1 The square meter is, for example, a substrate equal to or larger than 1.5 square meters. The resolution is primarily separated by the size of the substrate support of the large area substrate and the vibration and motion caused by the size of the substrate support.

An advantage of having a landing energy equal to or less than 2 keV, in particular a landing energy equal to or less than 1 keV, is that the main electron beam impinging on the substrate produces a stronger signal than the high energy electron beam. Since the layers deposited on the substrate are very thin, such layers are, for example, LTPS layers, and because high energy electrons penetrate deep into the substrate, ie below the layer, only a small amount of electrons can produce information containing information about the deposited layer. Detector signal. In contrast, low energy electrons, such as electrons having landing energy equal to or less than 2 keV, penetrate only into the shallow regions of the substrate, thus providing more information about the deposited layer. Thus, some embodiments as described herein can provide an improved image, such as an improved image of a grain boundary, even when the substrate is not surface etched. Moreover, some embodiments described herein provide an electron microscope image under vacuum conditions on a large area substrate, wherein the large area substrate is a substrate having an area equal to or greater than 1 square meter. An electron microscope image is provided under vacuum, thereby allowing a low landing energy having, for example, 2 keV or less, for example, equal to or less than 1 keV.

For high-resolution applications, it is beneficial to provide, for example, a landing energy equal to or less than 2 keV and a high charged particle beam energy in the beam column, and a landing energy equal to or less than 2 keV is equal to or less than 1 keV, the high charged particle beam energy is, for example, a beam energy equal to or greater than 10 keV, such as equal to or greater than 30 keV. Some embodiments may include deceleration prior to the substrate 10, such as within the objective lens and/or a coefficient between the objective lens and the substrate 10 being equal to or greater than 5, such as a factor equal to or greater than 10. For other applications, it is also possible to provide low landing energy, for example equal to or less than 2 keV, without deceleration, for example if the beam energy in the beam column is not higher than 2 keV.

According to some embodiments herein, which may be combined with other embodiments, an electron microscope image of a film having crystal grains is provided. For example, a scanning electron microscope image of a portion of a film deposited on a large area substrate is provided. This image is provided under vacuum conditions that allow low energy imaging where the beam energy of the electron beam on the film is equal to or less than 2 keV, such as about 1 keV. Thus, embodiments of the present disclosure relating to low energy imaging provide non-destructive imaging as compared to, for example, high energy electron beam imaging (< 7 keV) using an air scanning electron microscope (AIR SEM). Thus, electron beam observation can be provided during the manufacture of an optoelectronic device, such as a display fabricated on a large area substrate.

The charged particle beam microscope 100 as shown in FIG. 1 includes a detector 139 located in a detection vacuum region 130. The detector 139, also shown in FIG. 2, includes a scintillator device 136. The scintillator device 136 has an opening 201, such as an opening in the center of the scintillator device. The opening 201 is for passing the path of the main charged particle beam through the detector 139.

The scintillator device 136 is segmented to have two or more scintillator segments 236. According to some embodiments herein, which may be combined with other embodiments, there may be four scintillator segments, that is, a quad detector. The four segments make it possible to present a topographic image in both dimensions x and y of the substrate plane. Each image is shown in Figure 3A.

A light guide 134 is coupled to each of the scintillator segments 236. Additionally, one photomultiplier or another signal detecting element 132 can be provided for each light guide. Accordingly, some embodiments herein that may be combined with other embodiments include an Everhart-Thornley detector device as a detector 139. Some embodiments may also use an avalanche photodiode as a signal detecting component or a microchannel plate.

According to some embodiments herein, which may be combined with other embodiments, the scintillator device may be fabricated from a low noise scintillator having a lower bandwidth, which results in a better signal to noise ratio, which may be further averaged by flicker The plurality of segments of the device 136 are improved. For example, the scintillator can have a decay time of 50 nanoseconds to 100 nanoseconds, such as about 60 nanoseconds. Measurements in accordance with some embodiments of the present disclosure may have a pixel rate of 3 MHz to 10 MHz, such as approximately 5 MHz.

In some embodiments herein, which may be combined with other embodiments, the primary charged particle beam may be tilted to impinge on the substrate at a predetermined oblique beam landing angle. For example, the inclined primary charged particle beam can have an angle of inclination (relative to the normal on the substrate), that is, an angle of incidence greater than 5°, such as 10° to 20°, such as about 15°. The un-tilted primary charged particle beam may have an angle of incidence of less than 3°. According to some embodiments described herein, an imaged charged particle beam microscope as described herein can be imaged via one or more oblique beams. Thus, 3D imaging, imaging of steps, and other highly structured imaging can be improved.

According to an embodiment, a beam tilt having an inclination angle may be generated via a pre-lens deflection unit, and the pre-lens deflecting unit may include two deflection coils (deflection coils) ) to deflect the beam away from the optical axis. Due to these two stages, the beam can be deflected to appear to appear from a point coincident with the apparent location of the charged particle beam source. The pre-lens deflecting unit can be disposed between the charged particle source and the objective lens. An intra-lens deflecting unit may be disposed within the field of the objective lens such that the fields overlap. The in-lens deflecting unit can be a two-stage unit comprising two deflecting coils. The in-lens deflecting unit can redirect the direction of the beam such that the beam passes through the center of the objective lens at the optical axis, that is, the center of the focusing action. Reorientation is such that the charged particle beam strikes the surface of the substrate from one direction, and this direction is substantially opposite to the direction in which no beam passes through the optical axis. The combined action of the in-lens deflecting unit and the objective lens directs the primary charged particle beam back to the optical axis such that the primary charged particle beam hits the sample at a predetermined oblique beam landing angle.

According to another embodiment, a beam tilt can be generated via a deflection unit comprising two deflectors to deflect the beam away from the optical axis. Due to these two stages, the beam can be deflected to appear to appear from a point coincident with the apparent location of the charged particle beam source. The pre-lens deflecting unit can be disposed between the charged particle source and the objective lens. A Wien filter that generates an orthogonal electromagnetic field may be disposed above the pre-lens deflecting unit. The off-axis path of the charged particle beam causes the first chromatic aberration through the objective lens. The energy dispersion effect of the Wien filter introduces the same kind of second chromatic aberration as the first chromatic aberration. By appropriately selecting the electric field E of the Wien filter and the intensity of the magnetic field B, the second chromatic aberration can be adjusted to have the same magnitude but opposite direction as the first chromatic aberration. In fact, the second chromatic aberration substantially compensates for the first chromatic aberration in the plane of the substrate surface. The main charged particle beam is tilted by the off-axis travel through the objective lens and the focusing action of the objective lens.

According to further embodiments, which may be further or alternatively applied, the beam column may also be mechanically tilted to introduce a beam tilt, i.e., relative to the optical axis of the substrate. Tilting the charged particle beam by providing an oblique beam path within the beam column provides for faster switching between several beam angles and reduces the introduction of vibration as compared to mechanical motion.

According to some embodiments, an apparatus for inspecting a substrate, particularly an apparatus for inspecting a substrate for display manufacturing, is provided. This device includes a vacuum chamber as described herein. As described herein, the apparatus further includes a substrate support disposed in the vacuum chamber as described herein. The apparatus further includes a first imaged charged particle beam microscope and a second imaged charged particle beam microscope as described herein. The second imaged charged particle beam microscope is spaced from the first imaged charged particle beam microscope by a distance of at least 5 centimeters to 60 centimeters, such as from about 25 centimeters to 35 centimeters.

The image shown in Fig. 3A is an image of four segments of the detector 139 of the grain structure of the low temperature polysilicon. Techniques for fabricating TFTs on glass substrates include amorphous germanium (a-Si) processes and low temperature polysilicon (LTPS) processes. The main difference between the amorphous tantalum process and the low temperature polysilicon process is the electrical characteristics of the device and the complexity of the process. Low temperature polycrystalline germanium (LTPS) TFTs have high mobility, but the process for fabricating low temperature polycrystalline germanium TFTs is complicated. Although the amorphous germanium TFT has a low mobility, the process for fabricating the amorphous germanium TFT is simple. According to some embodiments described herein, a low temperature polysilicon TFT process system that can improve and control the process is beneficial. The low temperature polysilicon TFT process is an example of an embodiment that can be advantageously used in the embodiments described herein. In order to fabricate a low temperature polycrystalline germanium TFT, a deposited layer is partially melted by laser radiation. For example, the laser radiation can have a width of approximately 60 cm. Therefore, a distance of approximately 30 cm between the charged particle beam microscopes is sufficient in this region to provide a process analysis.

Provided is a method of inspecting a substrate, the method comprising generating a primary charged particle beam in a vacuum chamber and generating one or more images from the signal particle, wherein the one or more images are topographic images. As shown in FIG. 3A, a topographic image can be provided by imaging a portion of a film having a grain structure by a segmented detector, for example, a segmented detector having four segments. Quad detector. A plurality of topographical images as shown in FIG. 3A may be combined to a combined-perspective secondary electronic image as shown in FIG. 3B. According to some embodiments described herein, the image described herein can be compared to an optical image of a light source having two or more illumination angles, such as four illumination angles, wherein the values from the illumination angle of the imaging grain structure are Shadows can be used to obtain optical images. This is different from measuring with an oblique beam, which corresponds to a stereoscopic optical image.

In Figure 3B, an algorithm has been provided to highlight the grain boundaries of the grains of the LTPS film. The topographic image as shown in Fig. 3A or the combined image as shown in Fig. 3B can be used to detect, for example, an LTPS layer in the display industry, or other thin film layers having a grain structure. The electron beam observed according to the method described herein is capable of imaging a film having a grain structure such as a plurality of LTPS layers having a plurality of viewing angles. Improved terrain information can be provided. This allows a more accurate evaluation of the grain structure.

For comparison, Figure 4 presents the measurement results of the prior art. Figure 4 presents an image of a destructive measurement in which the LTPS layer has been etched and imaged with a high energy electron beam. The image surface can present a majority of the line 42 and can identify peaks corresponding to points 44. It will be apparent that one or more images as shown in Figure 3A or a combined image as shown in Figure 3B provides improved topographical information and is therefore used to better evaluate the grain structure. Furthermore, the images obtained as shown in Figures 3A and 3B are non-destructive. Thus, the imaged film or a corresponding substrate as shown in Figures 3A and 3B can be further processed in accordance with the embodiments described herein.

According to some embodiments described herein, a grain structure can be described by the size of the grains, the shape of the grains, the distribution of the grains, the area of the grains, and the like. Such parameters may be evaluated via statistical analysis methods corresponding to one or more of the parameters described above. For example, a feature of the grain of the grain structure can be used as an arithmetic mean, a quadratic average, a weighted average, and/or a median value.

According to some embodiments herein, which may be combined with other embodiments, the terrain information may be used by a software algorithm, such as detecting and analyzing grain structures in, for example, an LTPS grain structure. The calculation of grain structure characteristics may also include a watershed algorithm. The calculation based on one or more images may provide at least one feature of a grain of a grain structure selected from the group consisting of: an area of a grain of a grain structure, a length of a grain of a grain structure, a crystal of a grain structure a minimum size of the grain, a maximum size of the grain of the grain structure, a size of the grain of the grain structure along a predetermined direction, and a peak height of the grain boundary of the grain of the grain structure, and the above one Or multiple images are a combination of terrain images or terrain images. For example, a two-channel or multi-channel detector is used to image LTPS terrain from two or more quasi illumination sources in a top-down SEM image, where two channels or The multi-channel detector is, for example, a four-channel detector, and two or more viewing angles are, for example, four different viewing angles. Such two or more, for example four, viewing angles give surface information for detecting the size, uniformity, local distribution and all statistical data of the parameters used to describe the film having the grain structure. Measured and evaluated, and the film with grain structure is the LTPS layer.

According to some embodiments herein, which may be combined with other embodiments, statistical data on the characteristics of the grain structure and/or the parameters of the grain structure may be used to verify process parameters of a method of fabricating the deposited film. A process of feeding back a film having a grain structure can be provided. For example, a low temperature polysilicon (LTPS) TFT process can be controlled by electron beam review (EBR) according to some embodiments described herein.

According to some embodiments herein that may be combined with other embodiments, the algorithm for identifying statistical data of the features of the grain structure or the grain structure of the film may be applied to the combined image as shown in FIG. 3B. It has been found that applying these algorithms to the various topographical images shown in Figure 3A and combining the multiple values produced by such algorithms into a combined value for evaluating the grain structure may be beneficial.

According to some embodiments described herein, the area of the grains in the grain structure, the perimeter of the grains in the grain structure, and one or more dimensions of the grains in the grain structure can be measured. For example, a grain having a size of about 100 nm to 500 nm can be measured. According to some embodiments herein, which may be combined with other embodiments, a field of view that may be measured via scanning a primary electron beam over a substrate may have a size of up to 10 micrometers (μm).

The grains are typically surrounded by a grain boundary having a peak at the grain boundary, and the peaks may have a peak height equal to or less than 50 nm. According to some embodiments herein, which may be combined with other embodiments, the normal operation of a charged particle beam microscope has a non-inclined beam, i.e., the beam may have an angle of incidence of 3 or less on the substrate. The height of the peak can be determined by the length of the shadow of one or more terrain images. The length of the shadow can be calibrated to the measured peak height.

For calibration, the primary charged particle beam can be tilted to an angle that is equal to or greater than 5°, such as about 15°. A height of the height profile can be measured via an oblique beam image or two or more oblique beam images, and the height of the height profile is also the grain boundary of the grain. The above-mentioned one oblique beam image or two or more oblique beam images may be obtained on a film having a grain structure or on a substrate having an artificial alignment feature, and the film having a grain structure is, for example, a low temperature polysilicon ( LTPS) layer. The height of the grain boundaries of the grain structure or the absolute value of the artificial calibration features can be obtained from the measurement of an oblique beam. After the tilt is removed and the normal operating angle of incidence is provided, the topographic image can be measured and the length of the shadow can be calibrated to the previous measured height, where the normal operating angle of incidence is, for example, less than 3°, such as 0 The degree of tilt of °.

According to some embodiments, the apparatus for inspecting a large area substrate for display manufacturing may be an in-line device, that is, the device may be provided in accordance with another prior test or process, and Still another subsequent test or process is provided consistently, and the device may include a load lock for loading and unloading the substrate imaged by the charged particle beam microscope in the vacuum chamber, imaged charged The particle beam microscope is, for example, a scanning electron microscope (SEM). Since the charged particle beam for imaging on the substrate has a low energy, for example, equal to or less than 2 kV, the structure disposed on the substrate is not destroyed. Thus, the substrate can be provided to a display manufacturer for further processing. As understood herein, the number of substrates to be tested may be from 10% to 100% of the total number of substrates in the display manufacturer. Therefore, even if an apparatus for inspection and including an imaged charged particle beam microscope can be provided as an in-line tool, it is not necessary to test 100% of the substrates in the production line.

The vacuum chamber may include one or more valves that connect the vacuum chamber to another chamber, particularly when the device is an in-line device. Once a substrate is directed into the vacuum chamber, the one or more valves can be closed. Thus, the gas atmosphere in the vacuum chamber can be controlled via a vacuum generation technique, for example, via one or more vacuum pumps. One benefit of inspecting the substrate in a vacuum chamber is that vacuum conditions can facilitate inspection of the substrate using a low energy charged particle beam as compared to, for example, at atmospheric pressure. For example, the low energy charged particle beam may have a landing energy equal to or less than 2 keV, specifically equal to or less than 1 keV, such as 100 eV to 800 eV. The low energy beam does not penetrate deep into the inside of the substrate compared to the high energy beam, and thus can provide excellent information about, for example, a coating layer on the substrate.

Figure 5 is a flow diagram of some methods of inspecting a substrate, such as for display manufacturing. As shown in block 502, a large area of substrate is provided into the vacuum chamber, wherein the large area substrate has a film having a grain structure deposited on the substrate. The substrate can be measured as part of a conventional process, i.e., sample preparation that does not require similar etching. Furthermore, the measurement steps shown below are non-destructive and the substrate can be further processed after electron beam observation. As shown by block 504, a predominantly charged particle beam is produced and the primary charged particle beam strikes the film on the large area substrate under vacuum conditions. The vacuum conditions may result in a low energy landing energy on the substrate, for example, may have an energy equal to or less than 2 keV, such as 1 keV. Block 506 in Figure 5 refers to generating one or more terrain images. According to some embodiments described herein, the topographic image is produced by a non-tilted beam. Non-inclined beams are beneficial for easy control of electron beam microscopy and are therefore advantageous for throughput. The terrain image can be generated via a segmentation detector so that multiple viewing angles of the non-tilted beam can be achieved via one measurement. Topographic images can be used to determine one or more characteristics or parameters of the grain structure, such as grain structures in the LTPS layer.

Figure 6 is a flow chart of another method of inspecting a substrate. To calibrate the shadow length of the topographic image measured at a non-tilted beam angle, the primary charged particle beam can be tilted to an angle of incidence equal to or greater than 5°, such as 10° to 20°. The above steps are as shown in block 602. In block 604, one or more images of an area are generated via an oblique beam. As shown in block 606, the height of a structure or feature is measured from one or more images having an oblique beam. In block 608, the same area and/or the same structure of features are measured with a non-slanted beam, wherein one or more topographic images are generated, such as test images. The height measured as an absolute value as shown by block 606 is obtained from one or more topographic images that are calibrated to the length of the shadow of the image measured in block 608. In block 608, the test image is measured using a non-tilted beam such that the length of the shadow can be calibrated to the measured height of the absolute value. This calibration is shown as block 610. In block 612, the height of the peaks of the grain boundaries used to measure the grain structure is calibrated via calibration results and based on the shadow length. According to some embodiments described herein, the process illustrated by block 612 may be repeated a plurality of times based on the calibration generated by block 602 to block 610. Therefore, the calibration can be provided regularly or at a predetermined time interval. Measurements can be made during the observation of the substrate during the manufacturing process using a non-tilted beam. Calibration can be used to determine the height of the grain boundaries of the grain structure based on previously completed calibration results. This helps to increase the measurement speed and thus increase the yield. For example, the calibration needs to be performed once, and can be performed, for example, once a week or even once a month or even longer, where measurements are continued.

The disclosure has disclosed some embodiments, such as the scope of protection defined by the scope of the appended claims, which may be modified to provide other further embodiments, and the scope of protection is as disclosed in the appended claims. Defined.

10‧‧‧Substrate

42‧‧‧ line

44‧‧‧ points

100‧‧‧Charged particle beam microscope

110‧‧‧ gun chamber

112‧‧‧Electronic beam source

120‧‧‧vacuum chamber

122, 142, 146‧‧ ‧ pole pieces

123‧‧‧ concentrator lens

124, 144‧‧‧ coil

126‧‧‧electron optical components

130‧‧‧Detecting vacuum area

132‧‧‧Another signal detection component

134‧‧‧Light Guide

136‧‧‧Scintillator device

139‧‧‧Detector

140‧‧‧ objective lens

150‧‧‧Substrate support

152‧‧‧Upper electrode

154‧‧‧ lower electrode

170‧‧‧Scanning deflector assembly

201‧‧‧Opening

236‧‧‧Scintillator segmentation

Blocks 502, 504, 506, 602, 604, 606, 608, 610, 612‧‧

In the remainder of the specification, a complete and achievable disclosure of those skilled in the art is set forth in more detail, including reference to the drawings as follows: Figure 1 is for use in the description herein A side view of an imaged charged particle beam microscope of some embodiments. 2 is a detection device including a segmented scintillator for use with some embodiments described herein. Figure 3A is a topographical image in accordance with some embodiments of the present disclosure. 3B is a combined image of a plurality of topographical images combined in accordance with some embodiments of the present disclosure. Figure 4 is an image measured with a prior art air scanning electron microscope (SEM) in which an etched sample surface was measured. Figure 5 is a flow diagram of a method in accordance with some embodiments described herein, particularly a method for inspecting a large area substrate. Figure 6 is a flow diagram of a further method in accordance with some embodiments described herein, particularly for calibrating and inspecting, for example, a method for manufacturing a large area substrate.

Claims (20)

A method of inspecting a substrate, the method comprising: providing the substrate to a vacuum chamber, the substrate being a large area substrate, wherein the substrate has a film having a grain structure deposited on the substrate Generating a primary charged particle beam using an imaged charged particle beam microscope, wherein the primary charged particle beam impinges on the substrate in the vacuum chamber; and signal particles released from the substrate upon impact of the primary charged particle beam One or more images are generated, wherein the one or more images are topographic images. The method of claim 1, wherein a landing energy of the primary charged particle beam impinging on the substrate is equal to or less than 2 keV. The method of claim 1, wherein the one or more images are generated by a segmentation detector, in particular a four segment detector having four segments. The method of claim 2, wherein the one or more images are generated by a segmentation detector. The method of claim 3, wherein the one or more images are generated by a quad detector having four segments. The method of claim 3, wherein the one or more images are produced by the primary charged particle beam having an angle of inclination that is equal to or less than 3°. The method of claim 1, wherein the one or more images are produced by the primary charged particle beam having an angle of inclination that is equal to or less than 3°. The method of any one of clauses 1 to 7, further comprising: calculating at least one characteristic of a grain of the grain structure from the one or more images, the crystal of the grain structure The at least one characteristic of the particles is selected from: an area of the grain of the grain structure, a circumference of the grain of the grain structure, a minimum size of the grain of the grain structure, and a crystal of the grain structure a maximum dimension of the grain, a dimension of the grain of the grain structure along a predetermined direction, and a peak height of a grain boundary of the grain of the grain structure. The method of claim 8, wherein the at least one characteristic of the grain of the grain structure is an arithmetic mean value, a quadratic average value, a weighted average value, a minimum value, a maximum value, And at least one of a median value. The method of claim 8, wherein the calculating is performed using a watershed algorithm. The method of claim 8, wherein the two or more images of the one or more images are combined to form a combined image, and the calculation is performed using the combined image. The method of claim 8, wherein the calculating is performed using the one or more images to form one or more corresponding calculated values, and wherein the one or more corresponding calculated values are combined. The method of claim 8, further comprising: verifying a process parameter of a manufacturing method of the film via the at least one feature of the grain of the grain structure. The method of any one of clauses 1 to 7, further comprising: tilting the main charged particle beam by an angle which is equal to or greater than 5°; measuring a height of a height profile Rotating the primary charged particle beam back to a normal operating angle; generating one or more test images from the signal particles released by the substrate when the primary charged particle beam strikes at the normal operating angle, wherein the one or more test images The plurality of test images are terrain images; and the height of the measurements is used to calibrate a length of the shadow of the one or more images of the terrain image. The method of claim 8, further comprising: tilting the main charged particle beam by an angle equal to or greater than 5°; measuring a height of a height profile; tilting the main charged particle beam Returning to a normal operating angle; generating, by the substrate, one or more test images from signal particles released when the primary charged particle beam strikes at the normal operating angle, wherein the one or more test images are topographic images And using the measured height to calibrate a length of a shadow of the one or more images of the terrain image. The method of any one of clauses 1 to 7, wherein the method of inspection is an intermediate process of a manufacturing method of a display. The method of any one of clauses 1 to 7, further comprising: generating an additional primary charged particle beam by an additional imaged charged particle beam microscope, wherein the additional primary charged particle beam strikes On the substrate in the vacuum chamber; and additional signal particles released from the substrate upon impact of the additional primary charged particle beam to produce one or more additional images, wherein the one or more additional images It is a terrain image. The method of claim 17, wherein the primary charged particle beam and the additional primary charged particle beam have a distance from the surface of the substrate that is impacted on the substrate, the distance being from 5 cm to 60 cm. A computer readable medium having a plurality of instructions stored thereon, wherein when the instructions are executed, a charged particle beam microscope performs a method of inspecting a substrate as claimed in claim 1 The method of any one of item 7. The computer readable medium of claim 19, wherein the method further comprises: calculating at least one feature of the grain of the grain structure from the one or more images, the grain of the grain structure The at least one characteristic is selected from: an area of the grain of the grain structure, a circumference of the grain of the grain structure, a minimum size of the grain of the grain structure, a grain of the grain structure a maximum dimension, a dimension of the grain of the grain structure along a predetermined direction, and a peak height of a grain boundary of the grain of the grain structure.