In-situ detection device and grinding equipment

Abstract

The utility model provides an in-situ detection device and grinding equipment, and the in-situ detection device comprises a mechanical platform which is arranged between a suction cup and a wafer; the mechanical table can move along the direction parallel to the wafer; a detection unit is arranged on the mechanical table and used for obtaining the light intensity value of the reflected detection light in real time in the grinding process. The detection unit is provided with a transmitting end and a receiving end; the transmitting ends and the receiving ends are arranged in a one-to-one correspondence manner; the transmitting end is used for providing detection light for a wafer, the detection light enters through the back surface of the wafer and is reflected on the surface of a film layer on the wafer to form reflected light, and the receiving end is used for receiving the reflected light. According to the configuration, the detection unit is arranged between the suction cup and the wafer, so that the detection light can be incident from the back surface of the wafer, the detection unit and the detection light are not influenced by external factors such as abrasion of a grinding pad and disturbance of grinding liquid, and the detection precision is improved; and meanwhile, the movable mechanical table is arranged, so that in-situ detection can be continuously carried out on a specified position.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of semiconductor manufacturing, especially in situ detection device and polishing equipment. BACKGROUND

[0002] The existing CMP (Chemical Mechanical Polishing) in-situ end point detection (EPD) method mainly includes: motor current detection relying on friction, eddy current detection for detecting metal layer thickness and optical detection method.

[0003] Among them, the motor current detection and eddy current detection are affected by external factors such as polishing material, pad wear degree, and the detection accuracy is limited. And because the surface to be polished is closely attached to the polishing pad during polishing, the optical detection method, compared with the motor current detection and eddy current detection method, has higher accuracy and faster detection speed, but it needs to manufacture a complex detection window on the polishing pad, which increases the cost of the polishing pad as a consumable, and the influence of interference factors such as polishing pad wear on the detection process still needs to be considered during detection. At the same time, because the wafer and the polishing pad make self-rotating motion during the detection process, the motion relationship between the two is complex, which brings technical challenges to measure the specified area of the wafer, and needs to introduce accurate alignment technology or interrupt the measurement during the polishing process.

[0004] Therefore, how to reduce the influence of external interference factors such as polishing pad wear on detection accuracy, reduce the measurement cost, and realize the measurement of the specified area on the wafer has become a technical problem that needs to be solved by the person skilled in the art. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing an in-situ detection device and a polishing equipment to solve the problems that the existing optical detection method needs to install a detection window on the polishing pad to increase the cost, is easily affected by the polishing material and the polishing pad to cause the detection accuracy to drop and is difficult to realize the measurement of the specified position of the wafer.

[0006] In order to achieve the above purpose, the utility model provides an in-situ detection device, which comprises:

[0007] A mechanical table is arranged between the suction cup and the wafer.

[0008] The mechanical table is movable along the direction parallel to the wafer.

[0009] A detection unit is arranged on the mechanical table to obtain the light intensity value of the reflected detection light in real time during the polishing process.

[0010] The detection unit has a transmitting end and a receiving end; the transmitting end and the receiving end are arranged one by one; the transmitting end is used for providing detection light to the wafer, the detection light is incident on the back surface of the wafer, and is reflected on the surface of the film layer of the wafer to form reflected light; and the receiving end is used for receiving the reflected light.

[0011] Optionally, the in-situ detection device further comprises:

[0012] An optical unit is arranged between the detection unit and the back surface of the wafer, and is used for separating the detection light and the reflected light, and / or reducing reflection and refraction of the detection light and the reflected light when passing through different media.

[0013] Optionally, the optical unit comprises a light splitting piece and / or an anti-reflection film layer.

[0014] The light splitting piece is arranged between the transmitting end and the back surface of the wafer, and is used for separating the detection light and the reflected light, and reflecting the reflected light to the receiving end; and / or,

[0015] One side of the anti-reflection film layer is in contact with the back surface of the wafer, and the other side is in contact with the transmitting end and the receiving end respectively, so as to reduce reflection and refraction of the detection light and the reflected light when passing through different media.

[0016] Optionally, the anti-reflection film layer comprises a medium layer and / or an anti-reflection layer.

[0017] Optionally, the anti-reflection film layer comprises the medium layer and the anti-reflection layer; the medium layer is arranged close to the reflecting segment and the receiving end, and the anti-reflection layer is arranged close to the back surface of the wafer.

[0018] Optionally, the incident angle of the detection light provided by the transmitting end is arranged at an angle with the plane where the wafer is located.

[0019] When the incident angle of the detection light is perpendicular to the plane where the wafer is located, the optical unit comprises the light splitting piece.

[0020] Optionally, the mechanical table is movable along the direction close to or away from the wafer, so as to drive at least the optical unit to be in close contact with the back surface of the wafer during the detection process.

[0021] Optionally, the in-situ detection device further comprises a driving unit, the driving unit is connected with the mechanical table, and the driving unit is used for driving the mechanical table to move along the direction parallel to the wafer, and / or driving the mechanical table to move along the direction close to or away from the wafer.

[0022] In order to achieve the above object, the utility model also provides a kind of grinding equipment, comprising: grinding disc, grinding pad and the grinding head with in-situ detection device as described above;

[0023] The grinding pad is laid on the grinding disc, and the grinding head is located above the grinding pad for adsorbing the wafer to be ground;The grinding disc and the grinding head rotate around the shaft during grinding to cooperate with the grinding pad and grinding liquid to realize the grinding of the wafer.

[0024] Wherein, the grinding head is provided with a suction cup, and the in-situ detection device is arranged on the surface of the suction cup close to the wafer to obtain the light intensity value of the reflected detection light in real time during grinding.

[0025] Optionally, the wafer is provided with a process detection area, and the mechanical table drives the detection unit to the position corresponding to the suction cup and the process detection area during detection.

[0026] Compared with the existing optical detection method, the in-situ detection device and the grinding equipment provided by the present application have the following advantages:

[0027] The in-situ detection device provided by the present application sets the detection unit between the suction cup and the wafer, so that the detection light can be incident on the back of the wafer, avoiding the influence of the detection precision by the wear of the grinding pad;At the same time, the detection light is incident from the back of the wafer, which avoids the installation of complex detection window on the grinding pad, on the one hand, improves the detection efficiency and avoids the influence of the wear of the grinding pad on the detection process, on the other hand, also reduces the cost of the grinding pad as consumables;In addition, the mechanical table is movable along the direction parallel to the wafer, which can drive the detection unit to move to the detection area, since the suction cup is arranged on the grinding head, the grinding head rotates synchronously with the wafer during grinding, therefore, the above-mentioned detection unit can move synchronously with the wafer during grinding and continuously detect the specified position in-situ.

[0028] The grinding equipment provided by the present application sets the above-mentioned in-situ detection device on the surface of the suction cup close to the wafer, so that the detection light can be incident from the back of the wafer, which improves the detection precision and accurately determines the grinding termination point based on the obtained light intensity value, avoiding the situation that the grinding is insufficient or excessive, which affects the product yield.

[0029] Further, the mechanical table moves the detection unit to the position corresponding to the suction cup and the process detection area, so that the detection light emitted by the detection unit can be incident into the wafer from the area with simple film structure, reducing the interference of the complex film layer on the wafer to the detection light, and further improving the detection precision. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1The detection process schematic diagram of the first in-situ detection device is provided for the embodiment of the utility model.

[0031] Figure 2 The detection process schematic diagram of the second in-situ detection device is provided for the embodiment of the utility model.

[0032] Figure 3 The schematic diagram of the in-situ detection device in the termination point detection in the damascene process is provided for the embodiment of the utility model.

[0033] Figure 4 The schematic diagram of the in-situ detection device in the medium layer thickness calculation in the STI (Shallow Trench Isolation) process is provided for the embodiment of the utility model.

[0034] Figure 5 The schematic diagram of the detection light beam when the in-situ detection device calculates the medium layer thickness is provided for the embodiment of the utility model.

[0035] Figure 6 The schematic diagram of the in-situ detection device installed on the suction disc is provided for the embodiment of the utility model.

[0036] Wherein, the explanation of each figure mark is as follows:

[0037] 1-detection unit; 10-emitting end; 11-receiving end;

[0038] 2-optical unit; 20-splitting piece; 21-anti-reflection film layer; 210-medium layer; 211-anti-reflection layer

[0039] 3-mechanical table;

[0040] 4-wafer; 5-film layer; 6-suction disc. DETAILED DESCRIPTION

[0041] In order to make the purpose, advantages and characteristics of the utility model more clear, the utility model is further explained in detail below by combining with the drawings and specific embodiments. It should be noted that the drawings are all very simplified forms and are not drawn according to scale, and are only used to facilitate and clearly assist the purpose of explaining the embodiment of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing needs to be different, and sometimes different scales are used.

[0042] As used in this specification, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. The term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise. The term "and / or" means and or. The term "at least two" generally means two or more, unless the context clearly dictates otherwise. The terms "first," "second," "third," etc. are used only to describe a certain feature, and do not imply a relative importance or a specific number of the features. Thus, features defined with "first," "second," "third," etc. can include one or at least two of the features explicitly or implicitly. The terms "one end" and "the other end," and "proximal" and "distal" generally refer to two parts corresponding to each other, which not only include end points, but also include other relative positional relationships. The terms "mounting," "connecting," and "connecting" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be directly connected, or indirectly connected through an intermediate medium; can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in this specification, a component disposed in another component generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two components, and the two components can be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate component, and cannot be understood as indicating or implying the spatial positional relationship between the two components, i.e. one component can be in any position inside, outside, above, below or one side of another component, unless the context clearly indicates otherwise. The terms "up," "down," "top," "bottom" are generally relative positional relationships arranged according to the direction of gravity; the terms "vertical direction" and "vertical direction" generally refer to the direction along the gravity, which is generally perpendicular to the ground, and the terms "horizontal direction" and "horizontal plane direction" generally refer to the direction parallel to the ground; the specific meaning of the above terms in this specification can be understood according to the specific circumstances by those skilled in the art.

[0043] The utility model discloses a kind of in-situ detection device and grinding equipment, to solve the problem that the detection precision is reduced by the influence of grinding material and grinding pad in the existing optical detection method needs to install detection window on grinding pad to affect grinding process.

[0044] As can be understood by those skilled in the art, the existing endpoint detection methods (EPD) of CMP process mainly include motor current endpoint detection and optical reflection method. Among them, the motor current endpoint detection mainly monitors the change of motor current during polishing. When the polishing resistance (such as the change of material thickness or the change of contact surface) changes, the motor load current will fluctuate, so as to judge the endpoint. However, since the polishing resistance will also change due to the wear of the polishing pad, the monitoring accuracy of the above method is limited. The optical reflection method has higher accuracy than the motor current endpoint detection. It monitors the change of the intensity of the reflected light on the polishing surface, judges the material thickness or the metal coverage, and then determines the polishing endpoint. For example, in the STI CMP process, a detection window is used to measure the film thickness of the silicon dioxide film on the wafer surface by infrared spectrum interference method to determine the endpoint. However, the existing optical reflection method needs to set a detection window on the polishing pad, which is not only easy to be affected by external factors such as wear of the polishing pad, but also increases the cost of the polishing pad as a consumable. At the same time, since the wafer and the polishing pad make self-rotating motion respectively during the detection process, the motion relationship between them is complex, which brings technical challenges to the measurement of the specified area of the wafer, and requires the introduction of precise alignment technology or the interruption of measurement during the polishing process. Based on this, the embodiment provides an in-situ detection device and a polishing equipment. By setting the optical detection unit between the chuck and the wafer, the detection light beam is incident on the back surface of the wafer, which can effectively reduce the influence of the wear of the polishing pad on the detection result, and also avoid setting the detection window on the polishing pad to affect the polishing process, thereby improving the detection accuracy and efficiency.

[0045] Embodiment 1

[0046] Please refer to Figure 1 and Figure 3In the Damascus process, the film layer 5 on the wafer 4 is a metal thin film. The embodiment provides an in-situ detection device, which comprises a mechanical table 3 arranged between a chuck 6 and the wafer 4; the mechanical table 3 is movable along a direction parallel to the wafer 4; the mechanical table 3 is provided with a detection unit 1 for acquiring a light intensity value of reflected detection light in real time during the grinding process; the detection unit 1 has an emission end 10 and a receiving end 11; the emission end 10 and the receiving end 11 are arranged in one-to-one correspondence; the emission end 10 is configured to provide the wafer 4 with detection light, the detection light is incident on the back surface of the wafer 4 and is reflected at the interface between the wafer 4 and the metal thin film to form reflected light, and the receiving end 11 is configured to receive the reflected light. It should be noted that the detection light is a waveband capable of transmitting the wafer 4, such as infrared light or visible light. Since the metal has strong reflection ability to electromagnetic waves, when the surface of the wafer 4 is completely covered with the metal thin film, the reflectivity of the detection light at the interface between the wafer 4 and the metal thin film is close to 100%. Therefore, when the local pattern of the metal thin film is ground open, the light intensity value of the reflected light will change abruptly. The machine table can determine the grinding termination point based on the change rate of the light intensity value, and stop grinding when the grinding is performed to the grinding termination point, so as to avoid the conditions of under-grinding or over-grinding.

[0047] In this way, by arranging the detection unit 1 between the chuck 6 and the wafer 4, the detection light can be incident on the back surface of the wafer 4, and during the entire detection process, the detection unit 1 and the detection light are not affected by external factors such as wear of the grinding pad, disturbance of the grinding liquid, etc., thereby improving the detection accuracy; at the same time, the detection window is avoided to be installed on the grinding pad, so that the entire grinding process and the detection process are separated and do not interfere with each other; at the same time, by moving the mechanical table 3, the detection unit 1 is aligned with the to-be-detected area, and the detection unit 1 moves synchronously with the wafer 4 during grinding, so that the specified area on the wafer 4 can be detected in real time and in-situ.

[0048] Optionally, an optical unit 2 is arranged between the detection unit 1 and the back surface of the wafer 4, so as to Figure 1For example, the detection light passes through the wafer 4 to reach the detected metal film in an oblique incidence manner. At this time, the optical unit 2 can be provided with only the anti-reflection film layer 21, and the detection light emitted by the emitting end 10 passes through the anti-reflection film layer 21 to be incident on the back surface of the wafer 4. The anti-reflection film layer 21 can include a medium layer 210 and an anti-reflection layer 211. The medium layer 210 can be formed of a medium (such as monocrystalline silicon, polycrystalline silicon, etc.) having a refractive index close to that of the wafer 4; and the anti-reflection layer 211 can be formed of an anti-reflection material (such as SiO2, Si3N4, etc.). As can be understood by those skilled in the art, the medium layer 210 is used to eliminate the refraction phenomenon and avoid the interference of the reflected light into the receiving end 11 when the detection light enters the medium layer 210; and the anti-reflection layer 211 can reduce the reflection of the detection light at the interface between the medium layer 210 and the wafer 4. Of course, in other embodiments, the medium layer 210 and the anti-reflection layer 211 can also be provided with only one of them as needed. The provision of the anti-reflection film layer 21 can reduce the reflection and refraction of the detection light when it passes through different media, reduce the change of the light intensity value caused by the reflection and refraction of different media, and further improve the accuracy of the measured light intensity value.

[0049] When the detection light passes through the wafer 4 to reach the detected metal film in a perpendicular incidence manner, the optical unit 2 is preferably provided with a light splitting member 20 (such as shown in FIG. 2B). Figure 2 When the detection light passes through the wafer 4 to reach the detected metal film in a perpendicular incidence manner, the optical unit 2 is preferably provided with a light splitting member 20 (such as shown in FIG. 2B).

[0050] It should be noted that, regardless of the configuration of the optical unit 2, it should be integrally provided with the detection unit 1 in the present embodiment, that is, the mechanical table 3 can drive the detection unit 1 and the optical unit 2 to move together.

[0051] Further, the in-situ detection device can further include a driving unit (not shown in the figure) connected with the mechanical table 3. The driving unit can drive the mechanical table 3 to move in a direction parallel to the wafer 4, so that the mechanical table 3 moves to a designated measurement area; and the driving unit can also drive the mechanical table 3 to move in a direction approaching or away from the wafer 4. After the mechanical table 3 reaches the designated measurement area, the driving unit drives the mechanical table 3 to move in a direction approaching the wafer 4 and continuously press down to keep at least the optical unit 2 in contact with the back surface of the wafer 4 during the detection process, thereby avoiding the influence of the external environment on the detection light during the detection process.

[0052] As an optional embodiment, the driving unit can include a first motor for providing driving force to the mechanical table 3 and a track installed on the chuck, the mechanical table 3 being slidably connected to the track, thereby realizing the movement of the mechanical table 3 in the direction parallel to the wafer 4. Similarly, the driving unit can also include a second motor for providing driving force to a pneumatic cylinder, the pneumatic cylinder being a telescopic cylinder, one end of which is slidably connected to the track and the other end of which is connected to the mechanical table 3; after the mechanical table 3 is moved to the designated measurement area in the direction parallel to the wafer 4, the pneumatic cylinder is extended outward, thereby driving the mechanical table 3 to move in the direction close to the wafer 4 until the back surface of the wafer 4 is abutted.

[0053] Embodiment 2

[0054] Please refer to Figure 2 , Figure 4 and Figure 5 , in the STI (Shallow Trench Isolation) process, the film layer 5 on the wafer 4 is a silicon dioxide film. In this embodiment, the in-situ detection device also includes a mechanical table 3 and a detection unit 1. Different from Embodiment 1, since the silicon dioxide film in this embodiment is a non-metallic film, after the detection light passes through the interface between the wafer 4 and the silicon dioxide film, a part of the detection light is transmitted and a part of the detection light is reflected, the transmitted detection light is reflected again at the lower surface of the silicon dioxide film, returns to the upper surface of the silicon dioxide film, and interferes with the detection light reflected from the upper surface, and finally the reflected light formed after the interference is received by the receiving end 11. It should be noted that in the above embodiments, the detection light is a waveband that can transmit the wafer 4, such as monochromatic or polychromatic infrared coherent light.

[0055] As an optional embodiment, by using the principle of optical interference, the film thickness of the silicon dioxide film can be calculated by the intensity of the reflected light, and the polishing end point can be determined by the change of the film thickness. When a plurality of coherent lights with different wavelengths are used as detection light, more accurate film thickness information can be obtained by fitting.

[0056] As shown in Figure 4 and Figure 5 , when a parallel coherent light is vertically incident on the silicon dioxide film from the wafer 4, the incident light and the reflected light will occur respectively, and a part of the incident light is reflected at the interface between the silicon dioxide film and the polishing pad and re-incident on the wafer 4 to form interference with the original reflected light. The phase difference between the reflected light and the original reflected light can be obtained by formula 1:

[0057]

[0058] In the formula, d is the film thickness of the silicon dioxide film, n is the refractive index of the silicon dioxide film, and λ is the wavelength of the detection light. is the phase difference; d is the film thickness; n1 is the refractive index of the wafer 4; n2 is the refractive index of the silicon dioxide film; it is noted that although in this embodiment, the detection light is perpendicular to the wafer 4 (as shown in Figure 2 the patent does not necessarily require the detection light to be perpendicular to the incident. For the case of oblique incidence of the detection light, it can be calculated by the following formula:

[0059]

[0060] wherein, is the phase difference; d is the film thickness; n1 is the refractive index of the wafer 4; n2 is the refractive index of the silicon dioxide film; i is the incident angle; i' is the refraction angle.

[0061] And the refraction angle and the incident angle have the following relationship:

[0062] n1sini = n2sini' Formula 3

[0063] In combination with Formula 1 and Formula 2, we can get:

[0064]

[0065] The light intensity after the superposition of the two reflected lights is:

[0066]

[0067] wherein, I is the measured light intensity value; I1 and I2 are the original light intensity values of the two detection light beams.

[0068] It is noted that the half-wave loss is not considered in Formula 1, Formula 2 and Formula 4, such as the reflected light of the light-lean medium to the light-dense medium, which needs to be superimposed with the half-wave loss π / 2.

[0069] In combination with Formula 3 and Formula 4, other variables except the film thickness can be obtained, and then the corresponding film thickness can be calculated, and then the polishing end point can be determined according to the change of the film thickness. When using multiple different wavelengths of coherent light as detection light, the calculation can be performed respectively, and the fitting can be performed according to the relationship between the light intensity and the wavelength in Formula 4 and Formula 5 to obtain more accurate film thickness information.

[0070] Further, Figure 2For example, since the detection light is emitted in a perpendicular incidence manner, the optical unit 2 can include a light splitting piece 20 and an anti-reflection film layer 21. The light splitting piece 20 can be a half mirror placed at 45° with the detection light. The emission end 10 emits the detection light to the wafer 4, the detection light first passes through the light splitting piece 20, part of which is reflected to other areas, and another part is transmitted downward, and after passing through the anti-reflection film layer 21, it is vertically incident on the wafer 4. After being reflected on the upper surface and the lower surface of the silicon dioxide film respectively and interfering to form reflected light, it passes through the anti-reflection film layer 21 again and is reflected by the light splitting piece 20 to the receiving end 11. The anti-reflection film layer 21 can include a dielectric layer 210 and / or an anti-reflection layer 211. In this embodiment, the detection unit 1 is integrally arranged with the optical unit 2, and the mechanical table 3 can drive the detection unit 1 and the optical unit 2 to move together.

[0071] It should be noted that although the embodiment 1 in the present application is described by taking the metal thin film as an example, Figure 1 for example, the embodiment 2 is described by taking the silicon dioxide film as an example; Figure 2 but this does not mean that the metal thin film in the embodiment 1 can only be detected by using the oblique incidence manner as shown in Figure 1 for example, it can also be detected by using the perpendicular incidence manner as shown in Figure 2 correspondingly, the silicon dioxide film in the embodiment 2 can also not only be detected by using the perpendicular incidence manner as shown in Figure 2 for example, it can also be detected by using the oblique incidence manner as shown in Figure 1 .

[0072] The configuration of the driving unit can refer to the embodiment 1, and the embodiment will not be described here.

[0073] Embodiment 3

[0074] Please refer to Figure 6 , the utility model discloses a kind of grinding equipment, comprising: grinding disc (not shown in the figure), grinding pad (not shown in the figure) and the grinding head with in-situ detection device as described above;Grinding pad is laid on grinding disc, and grinding head is located above grinding pad, for adsorbing wafer 4 to be ground;Grinding disc and grinding head rotate around shaft during grinding, to cooperate with grinding pad and grinding liquid, realize the grinding of wafer;Wherein, suction cup 6 is provided on the grinding head, and in-situ detection device is arranged on the face of suction cup close to the wafer 4, to obtain the light intensity value after detection light reflection in real time during grinding.

[0075] So set, by the above-mentioned in-situ detection device is arranged on the face of suction cup 6 close to wafer 4, to make detection light can be incident from the back of wafer 4, improve detection precision, and can accurately determine grinding termination point based on the obtained light intensity value, avoid the case that grinding is insufficient or grinding is excessive and then affect product yield.

[0076] Optionally, the wafer 4 is provided with a process detection area in the scribe lane in design, the film layer structure of the process detection area is simple, when detecting, the mechanical table 3 drives the detection unit 1 to the position corresponding to the process detection area of the suction cup 6, so that the detection light beam emitted by the in-situ detection device can be shot into the wafer inside the area with simple film layer structure, the interference of the complex film layer on the wafer to the detection light beam is reduced, and the detection precision is further improved.

[0077] In summary, in the in-situ detection device and the grinding equipment provided in the embodiments of the present application, the in-situ detection device comprises: a mechanical table arranged between the suction cup and the wafer; the mechanical table is movable along a direction parallel to the wafer; the mechanical table is provided with a detection unit for acquiring the light intensity value of the reflected detection light in real time during the grinding process; the detection unit has an emission end and a receiving end; the emission end and the receiving end are arranged one by one in correspondence; the emission end is used for providing the wafer with detection light, the detection light is incident on the back surface of the wafer and is reflected on the film layer surface of the wafer to form reflected light, and the receiving end is used for receiving the reflected light.

[0078] In this way, by arranging the detection unit between the suction cup and the wafer, the detection light can be incident on the back surface of the wafer, so that the detection precision is not affected by the wear of the grinding pad; at the same time, the detection light is incident on the back surface of the wafer, which also avoids the installation of a complex detection window on the grinding pad, on the one hand, the detection efficiency is improved, and the influence of the wear of the grinding pad on the detection process is avoided, on the other hand, the cost of the grinding pad as a consumable is also reduced; in addition, the mechanical table is movable along a direction parallel to the wafer, so that the detection unit can be moved to the area to be detected, since the suction cup is arranged on the grinding head, the grinding head rotates synchronously with the wafer during the grinding process, therefore, the above-mentioned detection unit can move synchronously with the wafer during the grinding process, and continuously detects the specified position in-situ.

[0079] The above description is only a description of the preferred embodiments of the present application, and does not limit the scope of the present application in any way, any modification or modification of the above-mentioned content by a person skilled in the art belongs to the protection scope of the claims.

Claims

1. An in-situ detection device, characterized in that, include: The mechanical stage is positioned between the chuck and the wafer; The mechanical stage is movable in a direction parallel to the wafer; The machine platform is equipped with a detection unit, which is used to acquire the light intensity value after the detection light is reflected in real time during the grinding process; The detection unit has a transmitter and a receiver; the transmitter and the receiver are arranged in a one-to-one correspondence; the transmitter is used to provide detection light to the wafer, the detection light is incident on the back side of the wafer and reflected by the film surface on the wafer to form reflected light, and the receiver is used to receive the reflected light.

2. The in-situ detection device as described in claim 1, characterized in that, The in-situ detection device further includes: An optical unit is disposed between the detection unit and the back side of the wafer for separating the detection light from the reflected light, and / or reducing the reflection and refraction of the detection light and the reflected light as they pass through different media.

3. The in-situ detection device as described in claim 2, characterized in that, The optical unit includes a beam splitter and / or an anti-reflective coating; The beam splitter is disposed between the emitting end and the back side of the wafer, for separating the detection light and the reflected light, and reflecting the reflected light to the receiving end; and / or, One side of the anti-reflective film is in contact with the back of the wafer, and the other side is in contact with the transmitting end and the receiving end, respectively, so as to reduce the reflection and refraction of the detection light and the reflected light when passing through different media.

4. The in-situ detection device as described in claim 3, characterized in that, The anti-reflective coating layer includes a dielectric layer and / or an anti-reflective layer.

5. The in-situ detection device as described in claim 4, characterized in that, The anti-reflective coating includes the dielectric layer and the anti-reflective layer; the dielectric layer is disposed near the reflective section and the receiving end, and the anti-reflective layer is disposed near the back side of the wafer.

6. The in-situ detection device as described in claim 3, characterized in that, The incident angle of the detection light provided by the transmitting end is set at an angle to the plane where the wafer is located; When the incident angle of the detection light is perpendicular to the plane of the wafer, the optical unit includes the beam splitter.

7. The in-situ detection device as described in claim 2, characterized in that, The mechanical stage is movable in a direction approaching or away from the wafer to drive at least the optical unit to come into contact with the back of the wafer during the detection process.

8. The in-situ detection device as described in claim 7, characterized in that, The in-situ detection device further includes a driving unit connected to the mechanical stage. The driving unit is used to drive the mechanical stage to move in a direction parallel to the wafer, and / or to drive the mechanical stage to move in a direction closer to or farther from the wafer.

9. A grinding apparatus, characterized in that, include: A grinding disc, a grinding pad, and a grinding head having an in-situ detection device as described in any one of claims 1 to 8; The polishing pad is laid on the polishing disc, and the polishing head is located above the polishing pad for adsorbing the wafer to be polished; The grinding disc and the grinding head rotate around an axis during the grinding process to cooperate with the grinding pad and the grinding fluid to grind the wafer. The grinding head is equipped with a suction cup, and the in-situ detection device is located on the surface of the suction cup close to the wafer to acquire the light intensity value after the detection light is reflected in real time during the grinding process.

10. The grinding equipment as described in claim 9, characterized in that, The wafer is provided with a process inspection area, and the mechanical stage drives the inspection unit to the position of the chuck corresponding to the process inspection area during inspection.

Images