Optoelectronic sensor, chemical mechanical polishing apparatus, and object detection method

Abstract

Embodiments of the present application provide an optical sensor, a chemical mechanical polishing device and an object detection method. First invisible light having a first wavelength and second invisible light having a second wavelength are emitted to a detection area, wherein the reflectivity of the first invisible light and the second invisible light on an object to be detected is different, a first light receiving signal is generated according to the reflected light of the first invisible light and a second light receiving signal is generated according to the reflected light of the second invisible light, and a detection result of the object to be detected is determined according to the difference between the first light receiving signal and the second light receiving signal. Thus, the state of the object to be detected can be stably and accurately detected with a simple structure, and the detection efficiency and detection accuracy are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric transmission, and in particular to a photoelectric sensor, a chemical mechanical polishing device, and an object detection method. BACKGROUND

[0002] In the process of grinding a wafer by a chemical mechanical polishing (CMP) device, the wafer may be thrown out, and therefore, a sensor is usually arranged to detect whether the wafer is moved to be exposed from a platen, so as to monitor the wafer grinding process.

[0003] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application and for the convenience of understanding by those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art merely because they are described in the background of the present application. SUMMARY

[0004] The present inventors have found that a grinder usually has grinding pads of different colors, such as white, brown, black, etc., and needs to stably detect the presence or absence of a wafer in various wafer states, such as a front surface (wafer film-coated surface) / back surface (wafer polished surface) / original cutting surface, etc. Due to the color switching of the grinding pad and the diversification of the wafer surface state, the detection result is affected by the color, luster, transmittance, and reflectance of the wafer surface, which leads to the inability to stably and accurately detect whether the wafer has been moved or thrown out.

[0005] To solve the above problem or other similar problems, the present application provides a photoelectric sensor, a chemical mechanical polishing device, and an object detection method. Thus, the state of the object to be detected can be stably and accurately detected with a simple structure, and the detection efficiency and detection accuracy are improved.

[0006] According to an aspect of an embodiment of the present application, a photoelectric sensor is provided, the photoelectric sensor comprising,

[0007] a first detection light source arranged on a circuit substrate and emitting first invisible light having a first wavelength to a detection area,

[0008] a second detection light source arranged on the circuit substrate and emitting second invisible light having a second wavelength to the detection area, wherein the reflectivity of the first invisible light and the second invisible light on an object to be detected is different;

[0009] a light receiving unit configured to receive reflected light of the first invisible light and the second invisible light after the first invisible light and the second invisible light are projected to the detection area, respectively, and generate a first light receiving signal according to the reflected light of the first invisible light and a second light receiving signal according to the reflected light of the second invisible light;

[0010] a control unit configured to determine whether the detection area has the object to be detected according to a signal difference between the first light receiving signal and the second light receiving signal; and

[0011] an output unit configured to output a detection result of the object to be detected according to a determination result of the control unit.

[0012] In some embodiments, when the signal difference is greater than or equal to a threshold value, the detection result is that the detection area has the object to be detected.

[0013] When the signal difference is less than a threshold value, the detection result is that the detection area does not have the object to be detected.

[0014] In some embodiments, a first wavelength of the first invisible light and a second wavelength of the second invisible light are determined based on the object to be detected and / or environmental factors.

[0015] In some embodiments, a reflectivity on the object to be detected has a step at a third wavelength, the first wavelength of the first invisible light is greater than the third wavelength, and the second wavelength of the second invisible light is less than the third wavelength.

[0016] In some embodiments, the first wavelength of the first invisible light and the second wavelength of the second invisible light are also determined by a wavelength corresponding to one or more of the following environmental factors in air: oxygen, nitrogen, and moisture.

[0017] In some embodiments, the threshold value is determined based on the object to be detected, a reflectivity of the first wavelength of the first invisible light on the object to be detected, and a reflectivity of the second wavelength of the second invisible light on the object to be detected.

[0018] In some embodiments, the signal difference between the first light receiving signal and the second light receiving signal is an electrical signal difference, and the object to be detected is a wafer.

[0019] According to another aspect of embodiments of the present application, a chemical mechanical polishing apparatus is provided, including:

[0020] a polishing disc configured to rotate around a rotation axis, and having a polishing pad disposed thereon;

[0021] a wafer configured to be placed on the polishing pad and pressed by a platen; and

[0022] The photoelectric sensor according to any one of the above embodiments detects whether the wafer is exposed from the outer periphery of the press plate.

[0023] According to a further aspect of the embodiments of the present application, a method for detecting an object is provided, comprising,

[0024] emitting first invisible light having a first wavelength to a region to be detected,

[0025] emitting second invisible light having a second wavelength to the region to be detected, wherein the first invisible light and the second invisible light have different reflectivity on the object to be detected;

[0026] receiving reflected light of the first invisible light and the second invisible light after being projected to the region to be detected, respectively, and generating a first light receiving signal according to the reflected light of the first invisible light and a second light receiving signal according to the reflected light of the second invisible light;

[0027] determining whether the region to be detected has the object to be detected according to a signal difference between the first light receiving signal and the second light receiving signal; and

[0028] outputting a detection result of the object to be detected according to the determination result.

[0029] In some embodiments, when the signal difference is greater than or equal to a threshold value, the detection result is that the region to be detected has the object to be detected.

[0030] When the signal difference is less than the threshold value, the detection result is that the region to be detected does not have the object to be detected.

[0031] One of the beneficial effects of the embodiments of the present application is that first invisible light having a first wavelength and second invisible light having a second wavelength are emitted to a region to be detected, wherein the first invisible light and the second invisible light have different reflectivity on the object to be detected, a first light receiving signal is generated according to the reflected light of the first invisible light and a second light receiving signal is generated according to the reflected light of the second invisible light, and a detection result of the object to be detected is determined according to a difference between the first light receiving signal and the second light receiving signal. Thus, the state of the object to be detected can be stably and accurately detected with a simple structure, and the detection efficiency and the detection accuracy are improved.

[0032] The particular implementations of the present application described in detail in the specification and illustrated in the attached drawings are suggestive of the ways in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope to the particular implementations described herein. Embodiments of the present application encompass many changes, modifications, and alternatives in the spirit and scope of the appended claims.

[0033] Features described and / or illustrated with respect to one implementation can be used in one or more other implementations in the same or similar manner, in combination with or in place of features in other implementations, or in combination with or in place of one or more features described and / or illustrated with respect to one or more other implementations.

[0034] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to mean the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0036] Figure 1 is a schematic diagram of a photoelectric sensor of an embodiment of the present application;

[0037] Figure 2 is a schematic diagram showing the transmittance of different wavelengths of non-visible light on a particular wafer material;

[0038] Figure 3 is a schematic diagram showing the transmittance of different wavelengths of non-visible light on different wafer materials;

[0039] Figure 4 is a schematic diagram showing the transmittance of different wavelengths of non-visible light on different wafer materials under different environmental factors;

[0040] Figure 5 is a schematic diagram of a chemical mechanical polishing apparatus of an embodiment of the present application;

[0041] Figure 6 is a schematic diagram of a method of object detection of an embodiment of the present application. DETAILED DESCRIPTION

[0042] The foregoing and other features of the present application will become apparent to those skilled in the art upon a reading of the following detailed description that is provided in conjunction with the drawings. Like reference numerals refer to like elements throughout the drawings. In the description provided herein, a particular embodiment is disclosed in sufficient detail to establish enabling concepts. It will be apparent to those skilled in the art, however, that modifications and variations can be made in view of these concepts without departing from the scope or spirit of the application. Various embodiments of the application are described hereinafter with reference to the drawings. These embodiments are illustrative of the application and are not intended to limit the scope of the application. One skilled in the art will readily recognize from the following description that alternative embodiments of the

[0043] In the embodiments of the present application, the terms "first", "second" and the like are used to distinguish different elements from each other, but do not indicate the spatial arrangement or the time sequence of the elements, and the elements should not be limited by these terms. The term "and / or" includes any one and all combinations of the associated listed terms. The terms "include", "have" and the like mean the presence of the stated features, elements, elements or components, but do not exclude the presence or addition of one or more other features, elements, elements or components.

[0044] In the embodiments of the present application, the singular form "a", "an" and the like includes the plural form, and should be broadly understood as "one" or "a kind" rather than limited to the meaning of "one". In addition, the term "the" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. In addition, the term "according to" should be understood as "at least partially according to", unless the context clearly indicates otherwise.

[0045] Embodiments of the first aspect

[0046] The embodiments of the first aspect of the present application provide an optical sensor.

[0047] Figure 1 is a schematic diagram of an optical sensor 100 according to an embodiment of the present application. As shown in Figure 1 , the optical sensor 100 includes a first detection light source 10, a second detection light source 20, a light receiving part 30, a control part 40, an output part 50, and a circuit substrate 60.

[0048] The first detection light source 10 is disposed on the circuit substrate 60 and emits first invisible light having a first wavelength toward a to-be-detected area 70.

[0049] The second detection light source 20 is disposed on the circuit substrate 60 and emits second invisible light having a second wavelength toward the to-be-detected area 70. Wherein the first invisible light and the second invisible light have different reflectivities on the to-be-detected object.

[0050] The light receiving part 30 receives the reflected light of the first invisible light and the second invisible light after being projected onto the to-be-detected area 70, respectively, and the reflected light of the first invisible light generates a first light receiving signal and the reflected light of the second invisible light generates a second light receiving signal.

[0051] The control part 40 determines whether the to-be-detected area 70 has the to-be-detected object (not shown) according to the signal difference between the first light receiving signal and the second light receiving signal. Figure 1

[0052] The output part 50 outputs the detection result of the to-be-detected object according to the determination result of the control part 40.

[0053] ​Thus, the first invisible light with the first wavelength and the second invisible light with the second wavelength are emitted to the to-be-detected region, the reflectivity of the first invisible light and the second invisible light on the to-be-detected object is different, the first light receiving signal is generated according to the reflected light of the first invisible light, the second light receiving signal is generated according to the reflected light of the second invisible light, and the detection result of the to-be-detected object is determined according to the difference between the first light receiving signal and the second light receiving signal. Thus, the state of the to-be-detected object can be stably and accurately detected in a simple structure, and the detection efficiency and the detection accuracy are improved.

[0054] In some embodiments, in a case where the signal difference between the first light receiving signal and the second light receiving signal is greater than a threshold value, the detection result is that the to-be-detected region has the to-be-detected object; in a case where the signal difference between the first light receiving signal and the second light receiving signal is less than the threshold value, the detection result is that the to-be-detected region does not have the to-be-detected object.

[0055] Thus, by comparing the signal difference between the first light receiving signal and the second light receiving signal with a specific threshold value, it can be determined whether the to-be-detected object is detected. In addition, the present application is described by taking the reflectivity as an example, but the transmittance or the light transmittance can also be used, and the present application is not limited thereto.

[0056] In some embodiments, the first wavelength of the first invisible light and the second wavelength of the second invisible light are determined based on the to-be-detected object, and / or the first wavelength of the first invisible light and the second wavelength of the second invisible light are determined based on environmental factors.

[0057] In some embodiments, the to-be-detected object is a wafer, and the to-be-detected region is the circumferential outermost edge of a pressing plate on the upper part of the wafer. Optionally, the wafer is pressed on the center of a grinding pad by the pressing plate, and the wafer is polished. During the polishing of the wafer, the wafer will deviate from the center of the pressing plate due to the centrifugal force, causing the wafer to leak out from the edge of the pressing plate.

[0058] In some embodiments, by detecting whether the wafer appears at the circumferential outermost edge of the pressing plate, it can be determined whether the wafer deviates from the predetermined position to cause the risk of the wafer flying out. Specifically, the wafer material is a semiconductor material, such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), etc.

[0059] In some embodiments, the reflectivity on the to-be-detected object has a step at a third wavelength, the first wavelength of the first invisible light is greater than the third wavelength, and the second wavelength of the second invisible light is less than the third wavelength. In the present application, the "step" refers to, for example, a large change in reflectivity within a very short wavelength range; however, the present application is not limited thereto, and the specific meaning of the "step" can also be referred to related technologies.

[0060] Thus, two wavelengths on both sides of the certain wavelength where the step occurs are selected as the first wavelength and the second wavelength for detection, so that the signal difference between the first light receiving signal and the second light receiving signal is more obvious, and thus it is easier to determine whether the specific object to be detected is detected, and the detection accuracy is further improved.

[0061] In some embodiments, Figure 2 is a schematic diagram showing the transmittance of different wavelengths of invisible light on a specific wafer material, taking the material of the wafer as silicon, as shown in Figure 2 , wherein the silicon is a band gap semiconductor, and the band gap width between the conduction band and the valence band is large. After the light wavelength is 1200 nm (third wavelength), the frequency decreases, according to the quantum theory, the energy provided by each light quantum decreases accordingly, and it is not enough for the photon to cross the band gap, so the absorption rate of the photon decreases sharply, and the transmittance decreases sharply, and the reflectivity increases sharply.

[0062] On the contrary, the reflectivity of light of different wavelengths will not change much when it is projected onto the polishing pad. That is, for the wafer, the reflectivity will have a step near the third wavelength (1200 nm), but for the polishing pad (background material), the reflectivity will not have a step near the third wavelength (1200 nm). Optionally, taking the material of the wafer as silicon, the reflectivity of light of different wavelengths on the silicon has a step at the third wavelength (1200 nm), therefore, the first wavelength of the first invisible light can be determined as 1550 nm (greater than the third wavelength), and the second wavelength of the second invisible light is determined as 1000 nm (less than the third wavelength).

[0063] Taking the first wavelength of the first detection light source as 1550 nm and the second wavelength of the second detection light source as 1000 nm as an example, Table 1 below is a comparison table of reflectivity of different detection light sources projected onto different colored polishing pads and different shaped wafers.

[0064] Table 1

[0065]

[0066] In combination Figure 2 And taking the first row of Table 1 as an example, when the first wavelength of the first invisible light is W1 (for example, 1550 nm) and the second wavelength of the second invisible light is W2 (for example, 1000 nm), the reflectivity of the first invisible light after being projected onto the wafer is 50%, and the reflectivity of the second invisible light after being projected onto the wafer is 10%; that is, when the first invisible light and the second invisible light are projected onto the wafer, the reflectivity difference is 40%.

[0067] The reflectivity of the first non-visible light after being projected to the white polishing pad is 90%, and the reflectivity of the second non-visible light after being projected to the white polishing pad is 90%. Thus, the difference of the reflectivity of the first non-visible light and the second non-visible light is 0.

[0068] Therefore, if there is only the polishing pad in the to-be-detected area, the difference between the first light receiving signal and the second light receiving signal generated by the light receiving part is 0, and the difference between the first light receiving signal and the second light receiving signal generated by the light receiving part is less than the threshold value, and the control part can determine that there is no wafer in the to-be-detected area. If a wafer appears in the to-be-detected area, the difference between the first light receiving signal and the second light receiving signal generated by the light receiving part is 40%, and the difference between the first light receiving signal and the second light receiving signal generated by the light receiving part is greater than the threshold value, and the control part can determine that there is a wafer in the to-be-detected area. Thus, it can be determined whether the first non-visible light and the second non-visible light are transmitted to the wafer.

[0069] In some embodiments, the first wavelength of the first non-visible light and the second wavelength of the second non-visible light are determined based on the to-be-detected object.

[0070] Figure 3 is a schematic diagram showing the transmittance of light of different wavelengths on different wafer materials.

[0071] For example, for different wafer materials, the first wavelength of the first non-visible light and the second wavelength of the second non-visible light can be determined according to the wafer material, such as Figure 3 As shown, for the wafer being silicon (Si), the first wavelength of the first non-visible light is 1550 nm and the second wavelength of the second non-visible light is 1000 nm; for the wafer being gallium arsenide (GaAs), the first wavelength of the first non-visible light is 1000 nm and the second wavelength of the second non-visible light is 800 nm; for the wafer being germanium (Ge), the first wavelength of the first non-visible light is 2500 nm and the second wavelength of the second non-visible light is 1500 nm.

[0072] In some embodiments, the first wavelength of the first non-visible light and the second wavelength of the second non-visible light are determined based on environmental factors. Optionally, the first wavelength of the first non-visible light and the second wavelength of the second non-visible light are also determined by the wavelength corresponding to one or more of the following environmental factors in the air: oxygen, nitrogen, moisture. Optionally, the first wavelength of the first non-visible light and the second wavelength of the second non-visible light can also be determined by the wavelength corresponding to one or more of the following environmental factors in the air: ozone, carbon dioxide, methane, nitrous oxide.

[0073] For example, when deciding the first wavelength of the first invisible light and the second wavelength of the second invisible light, the wavelengths corresponding to oxygen, nitrogen and water in the air can be avoided. For other non-main components, they can be filtered out by the clean room. That is, in the specific implementation, the cleaned air can be used, and in this case, only the wavelengths corresponding to the main components such as oxygen, nitrogen and water need to be avoided. The present application is not limited to this, for example, only nitrogen can be avoided, or only oxygen can be avoided, and the like; that is, one of the above components or any combination thereof can be considered.

[0074] Figure 4 is a schematic diagram showing the transmittance of different wavelengths of invisible light on different wafer materials under different environmental factors. For example, as shown in Figure 4 , wherein the meaning of SW-R is short-wave infrared, the meaning of MW-R is medium-wave infrared, and the meaning of LW-R is long-wave infrared; Figure 4 The white part of the following figure indicates that the white wavelength part should be avoided due to the large attenuation caused by air and water vapor.

[0075] Therefore, in order to avoid the influence of water, the first wavelength of the first invisible light can be selected as 1500nm, and the second wavelength of the second invisible light can be selected as 1000nm. Figure 3 and Figure 4 The transmittance of various substances or materials is exemplarily described, but the present application is not limited thereto, and other parameters in Figure 3 and Figure 4 can be referred to related technologies, and will not be described here.

[0076] In some embodiments, the first wavelength of the first invisible light and the second wavelength of the second invisible light can also be determined based on environmental factors and the properties of the object to be detected. For example, when the object to be detected is silicon, and considering the influence of water in the environmental factors, the first wavelength of the first invisible light can be selected as 1550nm, and the second wavelength of the second invisible light can be selected as 1000nm.

[0077] For example, the maximum wavelength selection range can be determined as (200nm, 2000nm) first. If the object to be detected is a wafer, the first wavelength can be determined to be greater than 1200nm (third wavelength), and then the water vapor and the like corresponding to the wavelength are excluded in the range of (1200nm, 2000nm), and the first wavelength of the first invisible light can be selected as 1550nm. In addition, the second wavelength can be determined to be less than 1200nm (third wavelength), and then the water vapor and the like corresponding to the wavelength are excluded in the range of (200nm, 1200nm), and the second wavelength of the second invisible light can be selected as 1000nm.

[0078] Therefore, the first wavelength of the first invisible light and the second wavelength of the second invisible light are determined according to the object to be detected, different wavelengths are set for specific objects to be detected, and the detection accuracy is further improved. In addition, different first wavelengths of the first invisible light and different second wavelengths of the second invisible light are selected according to environmental factors, so that the detection process is more stable, is not disturbed by environmental factors such as water vapor and CO2, and the detection accuracy of the object to be detected is improved.

[0079] In some embodiments, the signal difference between the first light receiving signal and the second light receiving signal is an electrical signal difference. Optionally, after the light receiving unit receives the reflected light of the first invisible light and the reflected light of the second invisible light respectively after the first invisible light and the second invisible light are projected onto the detection area, the reflected light of the first invisible light and the reflected light of the second invisible light are converted into electrical signals respectively, and the first light receiving signal of the reflected light of the first invisible light and the second light receiving signal of the reflected light of the second invisible light are generated, and then the control unit compares the electrical signals of the first light receiving signal and the second light receiving signal to obtain the signal difference between the first light receiving signal and the second light receiving signal. In addition, the conversion of the optical signal into the electrical signal can refer to the prior art, and the present application does not limit this.

[0080] In some embodiments, the threshold is determined based on the object to be detected and the first wavelength of the first invisible light and the second wavelength of the second invisible light.

[0081] For example, in Table 1, the minimum reflectivity difference value on the wafer of each row is 40%, so the threshold can be set to 3dB. When the electrical signal difference between the first light receiving signal and the second light receiving signal is greater than or equal to 3dB, it is confirmed that the object to be detected exists, and when the electrical signal difference between the first light receiving signal and the second light receiving signal is less than 3dB, it is confirmed that the object to be detected does not exist. Optionally, different thresholds can be set by using different first wavelengths of the first invisible light and different second wavelengths of the second invisible light and different wafer materials, and the present application does not limit this.

[0082] For example, in combination with Table 1, when the wafer does not move to the edge of the platen, the first invisible light and the second invisible light are projected onto the polishing pad, the polishing pad reflects the reflected light of the first invisible light and the reflected light of the second invisible light to the light receiving unit, the light receiving unit generates the first light receiving signal and the second light receiving signal corresponding to the reflected light of the first invisible light and the reflected light of the second invisible light, and the control unit detects that the intensity of the first light receiving signal and the intensity of the second light receiving signal are the same. Therefore, the signal difference between the first light receiving signal and the second light receiving signal is 0, the control unit determines that the detection area does not have a wafer, and the output unit outputs the above detection result to an external device.

[0083] For another example, when the wafer moves to the edge of the pressing plate, the first invisible light and the second invisible light are respectively projected onto the wafer, the wafer reflects the reflected light of the first invisible light and the reflected light of the second invisible light to the light receiving part, the light receiving part generates the first light receiving signal and the second light receiving signal corresponding to the reflected light of the first invisible light and the reflected light of the second invisible light, and the control part detects that the intensity of the first light receiving signal and the intensity of the second light receiving signal are different by more than a threshold value (3 dB), the control part determines that the to-be-detected area has a wafer, and the output part outputs the above detection result to an external device.

[0084] Therefore, by the characteristic that the wafer has different reflectivities to different wavelengths of invisible light, it can be accurately detected whether the wafer is located in a specific area, so that the state of the to-be-detected object can be stably and accurately detected with a simple structure, and the detection efficiency and detection accuracy are improved.

[0085] In some embodiments, the first detection light source and the second detection light source can respectively use two independent light receiving parts. Alternatively, the first detection light source and the second detection light source can simultaneously emit the first invisible light and the second invisible light to the to-be-detected area, and then the two independent light receiving parts respectively receive the reflected light of the first invisible light after being projected to the to-be-detected area and the reflected light of the second invisible light after being projected to the to-be-detected area, and then generate the first light receiving signal and the second light receiving signal respectively. In addition, the specific process of generating the first light receiving signal and the second light receiving signal is similar to the above-mentioned embodiments of the present application, which will not be repeated here.

[0086] Therefore, by setting two independent light receiving parts, the size of the photosensor is increased, and the wavelength range is wider; and compared with the first detection light source and the second detection light source needing to share the same light receiving part through time division multiplexing, using two independent light receiving parts can simultaneously project the first detection light source and the second detection light source, so that the detection result is more accurate.

[0087] The above embodiments are only exemplary, but the present application is not limited thereto, and appropriate modifications can be made on the basis of the above embodiments. For example, each of the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0088] According to the above embodiments of the present application, by the characteristic that the wafer has different reflectivities to different wavelengths of invisible light, it can be accurately detected whether the wafer is located in a specific area, so that the state of the to-be-detected object can be stably and accurately detected with a simple structure, and the detection efficiency and detection accuracy are improved.

[0089] Embodiments of the second aspect

[0090] The embodiment of the second aspect of the present application provides a chemical mechanical polishing device, which comprises the photoelectric sensor 100 in the embodiment of the first aspect, and the same content as in the embodiment of the first aspect will not be repeated here.

[0091] Figure 5 The chemical mechanical polishing device 200 is an embodiment of the present application. As shown in Figure 5 The chemical mechanical polishing device 200 comprises:

[0092] The polishing disc 201 rotates around the rotation axis 205, and the polishing pad 202 is arranged on the polishing disc 201;

[0093] The wafer 203 is placed on the polishing pad 202 and is pressed by the platen 204; and

[0094] The photoelectric sensor 100 as described in the embodiment of the first aspect detects whether the wafer 203 is exposed from the outer periphery of the platen 204.

[0095] Therefore, the first invisible light with the first wavelength and the second invisible light with the second wavelength are emitted to the to-be-detected area, the reflectivity of the first invisible light and the second invisible light on the to-be-detected object is different, the first light receiving signal is generated according to the reflected light of the first invisible light, the second light receiving signal is generated according to the reflected light of the second invisible light, and the detection result of the to-be-detected object is determined according to the difference between the first light receiving signal and the second light receiving signal. Therefore, the state of the to-be-detected object can be stably and accurately detected with a simple structure, and the detection efficiency and the detection accuracy are improved.

[0096] In some embodiments, whether the wafer is at risk of flying out can be detected by arranging a plurality of photoelectric sensors 100 in the circumferential direction of the platen 204. For example, four photoelectric sensors are arranged on the upper and lower parts and the left and right parts of the platen, so that whether the wafer is at risk of flying out in each direction can be detected, and the detection accuracy is further improved.

[0097] For the application of the chemical mechanical polishing device of the embodiment of the present application, the descriptions of the components of the photoelectric sensor of the embodiment of the first aspect can be referred to.

[0098] According to the above-mentioned embodiments of the present application, one of the beneficial effects of the embodiments of the present application is that, by using the characteristic that the invisible light with different wavelengths has different reflectivity on the wafer, whether the wafer is located in a specific area can be accurately detected, so that the state of the to-be-detected object can be stably and accurately detected with a simple structure, and the detection efficiency and the detection accuracy are improved.

[0099] Embodiment of the third aspect

[0100] The embodiment of the third aspect of the present application provides a method for object detection. The photoelectric sensor 100 in the embodiment of the first aspect is applied, and the same content as in the embodiment of the first aspect will not be repeated.

[0101] Figure 6 is a schematic diagram of the method for object detection in the embodiment of the present application. As shown in the figure, Figure 6 the method comprises the following steps.

[0102] In step 601, first invisible light with a first wavelength is emitted to a region to be detected.

[0103] In step 602, second invisible light with a second wavelength is emitted to the region to be detected, wherein the reflectivity of the first invisible light and the second invisible light on the object to be detected is different.

[0104] In step 603, the reflected light of the first invisible light and the second invisible light after being projected to the region to be detected is respectively received, and a first light receiving signal is generated according to the reflected light of the first invisible light and a second light receiving signal is generated according to the reflected light of the second invisible light.

[0105] In step 604, whether the region to be detected has the object to be detected is determined according to the signal difference between the first light receiving signal and the second light receiving signal.

[0106] In step 605, a detection result of the object to be detected is output according to the determination result.

[0107] Therefore, the first invisible light with the first wavelength and the second invisible light with the second wavelength are emitted to the region to be detected, wherein the reflectivity of the first invisible light and the second invisible light on the object to be detected is different, the first light receiving signal is generated according to the reflected light of the first invisible light and the second light receiving signal is generated according to the reflected light of the second invisible light, and the detection result of the object to be detected is determined according to the difference between the first light receiving signal and the second light receiving signal. Therefore, the state of the object to be detected can be stably and accurately detected with a simple structure, and the detection efficiency and the detection accuracy are improved.

[0108] In some embodiments, the method can further comprise:

[0109] In the case where the signal difference is greater than or equal to a threshold value, the detection result is that the region to be detected has the object to be detected.

[0110] In the case where the signal difference is less than the threshold value, the detection result is that the region to be detected does not have the object to be detected.

[0111] The object detection method of the embodiments of the present application can also refer to the descriptions of the photoelectric sensor of the embodiments of the first aspect and the components of the chemical mechanical polishing apparatus of the embodiments of the second aspect.

[0112] According to the above embodiments of the present application, one of the beneficial effects of the embodiments of the present application is that, by using the characteristic that different wavelengths of invisible light have different reflectivity on the object to be detected (e.g., a wafer), it can be accurately determined whether the object to be detected is located in a specific area, so that the state of the object to be detected can be stably and accurately detected with a simple structure, and the detection efficiency and accuracy are improved.

[0113] Embodiments of the fourth aspect

[0114] The embodiments of the fourth aspect of the present application can provide an electronic device including a processor and a memory. The memory stores data and programs and is coupled to the processor. The processor can be configured to execute the programs to implement the method in the embodiments of the third aspect.

[0115] For example, the electronic device is connected with a photoelectric sensor including Figure 1 The processor of the electronic device can perform the functions of the control unit 40 and the output unit 50 as shown in the first detection light source 10, the second detection light source 20, and the light receiving unit 30.

[0116] The processor is configured to control the photoelectric sensor to emit first invisible light having a first wavelength to a detection area, control the photoelectric sensor to emit second invisible light having a second wavelength to the detection area, wherein the reflectivity of the first invisible light and the second invisible light on the object to be detected is different, control the photoelectric sensor to receive reflected light after the first invisible light and the second invisible light are projected to the detection area, respectively, and generate a first light receiving signal according to the reflected light of the first invisible light and a second light receiving signal according to the reflected light of the second invisible light, determine whether the detection area has the object to be detected according to the signal difference of the first light receiving signal and the second light receiving signal, and output a detection result of the object to be detected according to the determination result.

[0117] The control unit described in combination with the embodiments of the present application can be directly embodied as hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings and / or a combination of one or more of the functional block diagrams can correspond to each software module of the computer program flow, or to each hardware module. These software modules can correspond to the steps shown in the embodiments, respectively. These hardware modules can be implemented by, for example, a field programmable gate array (FPGA) that fixes the software modules.

[0118] The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC. The software modules can be stored in a memory of the mobile terminal, or in a memory card that can be inserted into the mobile terminal. For example, if the electronic device uses a MEGA-SIM card or a flash memory device with a large capacity, the software modules can be stored in the MEGA-SIM card or the flash memory device.

[0119] One or more of the functional blocks described in the figures and / or one or more combinations of the functional blocks can be implemented as a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof, for performing the functions described in this disclosure. One or more of the functional blocks described in the figures and / or one or more combinations of the functional blocks can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0120] The present application has been described above with the attachment of particular embodiments, and it is clear to those skilled in the art that such description is exemplary only and not a limitation of the scope of the present application. Various modifications and changes can be made to the present application in accordance with the principles of the present application, and such modifications and changes are intended to be within the scope of the present application.

Claims

1. A photosensor, characterized by, The photoelectric sensor includes, a first detection light source disposed on a circuit substrate and emitting first invisible light having a first wavelength toward a region to be detected, a second detection light source disposed on the circuit substrate and emitting second invisible light having a second wavelength toward the region to be detected, wherein the first invisible light and the second invisible light have different reflectivities on an object to be detected; a light receiving section that receives reflected light of the first invisible light and the second invisible light after the first invisible light and the second invisible light are projected toward the region to be detected, respectively, and generates a first light receiving signal from the reflected light of the first invisible light and a second light receiving signal from the reflected light of the second invisible light; a control section that determines whether or not the region to be detected has the object to be detected based on a signal difference between the first light receiving signal and the second light receiving signal; and an output section that outputs a detection result of the object to be detected based on a determination result of the control section, wherein the first wavelength of the first invisible light and the second wavelength of the second invisible light are determined based on the object to be detected and environmental factors, wherein the reflectivity on the object to be detected has a step at a third wavelength, the first wavelength of the first invisible light is greater than the third wavelength, and the second wavelength of the second invisible light is less than the third wavelength.

2. The photoelectric sensor according to claim 1, wherein in a case where the signal difference is greater than or equal to a threshold value, the detection result is that the region to be detected has the object to be detected, in a case where the signal difference is less than the threshold value, the detection result is that the region to be detected does not have the object to be detected.

3. The photosensor of claim 1, wherein, The first wavelength of the first invisible light and the second wavelength of the second invisible light are determined based on at least one or more of wavelengths corresponding to oxygen, nitrogen, and moisture in the air.

4. The photosensor of claim 2, wherein, The threshold value is determined based on the object to be detected and the reflectivity of the first invisible light on the object to be detected and the reflectivity of the second invisible light on the object to be detected.

5. The photosensor of claim 1, wherein, The signal difference between the first light receiving signal and the second light receiving signal is an electrical signal difference, and the object to be detected is a wafer.

6. A chemical mechanical polishing apparatus characterized by comprising: The chemical mechanical polishing apparatus includes: a polishing pad that rotates around a rotation axis, the polishing pad having a polishing pad disposed thereon; a wafer that is placed on the polishing pad and is pressed by a platen; and a photoelectric sensor according to any one of claims 1 to 5 that detects whether or not the wafer is exposed from an outer periphery of the platen.

7. An object detection method characterized by, The method includes, emitting first invisible light having a first wavelength toward a region to be detected, emitting second invisible light having a second wavelength toward the region to be detected, wherein the first invisible light and the second invisible light have different reflectivities on an object to be detected; receiving reflected light of the first invisible light and the second invisible light after the first invisible light and the second invisible light are projected toward the region to be detected, respectively, and generating a first light receiving signal from the reflected light of the first invisible light and a second light receiving signal from the reflected light of the second invisible light; determine whether the to-be-detected region has the to-be-detected object according to a signal difference between the first light receiving signal and the second light receiving signal; and output a detection result of the to-be-detected object according to the determination result, wherein a first wavelength of the first invisible light and a second wavelength of the second invisible light are determined based on the to-be-detected object and environmental factors, wherein a reflectivity on the to-be-detected object has a step at a third wavelength, the first wavelength of the first invisible light is greater than the third wavelength, and the second wavelength of the second invisible light is less than the third wavelength.

8. The object detection method of claim 7, wherein in a case where the signal difference is greater than or equal to a threshold value, the detection result is that the to-be-detected region has the to-be-detected object; in a case where the signal difference is less than the threshold value, the detection result is that the to-be-detected region does not have the to-be-detected object.

Images