Monitoring device of diamond dresser in chemical mechanical polishing equipment

Abstract

The utility model provides a monitoring device for a diamond dresser in chemical mechanical polishing equipment, which comprises an optical sensor arranged on the outer side of a diamond dressing head, moving along with the movement of the diamond dresser, scanning an optical signal emitted by a polishing pad dressed by the diamond dressing head, and receiving an optical signal reflected back from the polishing pad; the image shooting device is arranged at the bottom of the container and is used for shooting photos before and after the diamond finishing head works; and the detection processing part is in communication connection with the optical sensor and the image shooting device and is used for processing data output by the optical sensor and the image shooting device so as to monitor whether the diamond falls off or not. According to the technical scheme of the utility model, through the optical sensor and the image shooting, dual monitoring of diamond falling is realized, the monitoring result is accurate, and the influence of diamond falling on the finishing effect and the damage to a wafer are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical grinding, in particular to a monitoring device for a diamond dresser in chemical mechanical grinding equipment. Background Art

[0002] In the semiconductor CMP process, the surface of the wafer needs to be ground. Generally, a grinding pad is used to grind the surface of the wafer, and a grinding liquid needs to be added to the surface of the grinding pad during grinding. In order to evenly distribute the grinding liquid on the grinding pad, a diamond dresser is generally used. The diamond dresser moves relative to the surface of the grinding pad, which can evenly distribute the grinding liquid on the grinding pad.

[0003] In addition, as the grinding progresses, some grinding by-products will be produced, such as: grinding particles, dry grinding liquid particles, etc. These grinding by-products will fall into the pores and grooves on the surface of the grinding pad, causing the grinding pad to become smooth. This effect is called "glazing", which will cause the grinding rate to decrease and cause scratches on the surface of the wafer, affecting the surface of the wafer. The relative movement of the diamond dresser on the surface of the grinding pad can not only make the grinding liquid evenly distributed on the grinding pad, but also take away the grinding by-products on the surface of the grinding pad at the same time, which can not only maintain the rough state of the grinding pad surface, but also reduce the scratch defects caused by impurities on the wafer during the grinding process.

[0004] However, there are many diamonds distributed on the surface of the diamond dresser, and sometimes the diamonds will fall off, which will affect the effect of the diamond dresser. If the fallen diamonds fall on the grinding pad, the ground wafer will be scratched, causing the wafer to be scrapped, resulting in a large amount of losses. Utility Model Content

[0005] The utility model provides a monitoring device for a diamond dresser in a chemical mechanical grinding device, so as to solve the problem in the prior art that diamonds fall off, affecting the dressing effect and causing a large amount of losses.

[0006] In order to solve the above technical problems, the utility model is implemented through the following technical solutions:

[0007] The utility model provides a monitoring device for a diamond dresser in a chemical mechanical grinding device, wherein the diamond dresser comprises: a diamond dresser head, a swing arm and a container, wherein the diamond dresser head is located at one end of the swing arm; before and after the diamond dresser works, the diamond dresser head is located in the container, and the monitoring device comprises:

[0008] An optical sensor, which is disposed outside the diamond dressing head and moves along with the movement of the diamond dresser. The optical sensor sends out a light signal to scan the grinding pad trimmed by the diamond dressing head and receives a light signal reflected from the grinding pad;

[0009] An image shooting device is disposed at the bottom of the container to shoot pictures of the diamond trimming head before and after the diamond trimming head works; and

[0010] The detection processing part is connected to the optical sensor and the image capturing device for processing the data output by the optical sensor and the image capturing device; wherein:

[0011] The detection and processing part determines the particle size of the polishing pad according to the reflected light signal or determines its spectrum according to the reflected light signal; when the particle size detected by the detection and processing part exceeds a preset value or the spectrum detected by the detection and processing part is within a preset spectrum range, whether diamonds fall during the operation of the diamond dresser is monitored in combination with photos before and after the operation of the diamond dresser.

[0012] Optionally, the optical sensor is an infrared spectrum sensor.

[0013] Optionally, the infrared spectrum sensor is a miniaturized Fourier transform infrared spectrum sensor.

[0014] Optionally, the detection and processing part is a data analysis and processing module in the chemical mechanical polishing equipment.

[0015] The monitoring device of the diamond dresser in the chemical mechanical polishing equipment provided by the utility model can scan the surface of the polishing pad through the optical sensor during the polishing process of the diamond dresser to determine whether the particle size on the surface of the polishing pad exceeds a preset value, and if so, it means that there may be diamonds dropped on the surface of the polishing pad; then, by comparing the photos of the diamond dresser head taken by the image shooting device before and after the work, it can be determined whether the diamond dresser has dropped during the working process; the monitoring device of the utility model can timely detect the drop of diamonds, avoid the drop of diamonds to affect the polishing effect of the corrector, and avoid the drop of diamonds to damage the wafer, thereby avoiding losses; and dual monitoring is achieved through the optical sensor and the image shooting device, so that the monitoring result is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1a A side view of a diamond dresser in one state according to an embodiment of the utility model;

[0018] Figure 1b A top view of a diamond dresser in one state according to an embodiment of the utility model;

[0019] Figure 1c A side view of a diamond dresser according to an embodiment of the present invention in another state;

[0020] Figure 2 A schematic diagram of a monitoring device according to an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of light signal determination of an optical sensor according to an embodiment of the utility model;

[0022] Figure 4 A schematic diagram of the installation position of an optical sensor of a monitoring device according to an embodiment of the utility model;

[0023] Figure 5 A schematic diagram of the installation position of an optical sensor of a monitoring device according to another embodiment of the utility model;

[0024] Description of reference numerals:

[0025] 11-Diamond trimming head,

[0026] 12-Swing arm,

[0027] 13- receiving container;

[0028] 21- abrasive pad;

[0029] 31- Optical sensor,

[0030] 32- Image capture device. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] In the description of the utility model specification, it is necessary to understand that the orientation or position relationship indicated by the terms "upper part", "lower part", "upper end", "lower end", "lower surface", "upper surface", etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0033] In the description of the utility model specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0034] In the description of the present invention, "plurality" means multiple, such as two, three, four, etc., unless otherwise clearly and specifically defined.

[0035] In the description of the utility model specification, unless otherwise clearly specified and limited, the term "connection" and other terms should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.

[0036] The following specific embodiments are used to describe the technical solution of the utility model in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0037] In one embodiment of the present invention, a monitoring device for a diamond dresser in a mechanical grinding device is provided. The diamond dresser comprises: a diamond dresser head 11, a swing arm 12 and a container 13, please refer to Figure 1a , 1b, 1c. The diamond trimming head 11 is located at one end of the swing arm 12; before and after the diamond trimmer works, the diamond trimming head 11 is located in the receiving container 13, such as Figure 1a , 1b shown. Figure 1c The schematic diagram of the diamond dresser during operation is shown. The swing arm 12 can drive the diamond dresser head 11 to swing on the surface of the grinding pad 21 .

[0038] Furthermore, the monitoring device includes: an optical sensor 31, an image capturing device 32, and a detection processing part.

[0039] Please refer to Figure 2 , the optical sensor 31 is arranged on the outside of the diamond dressing head 11, and moves with the movement of the diamond dresser. The optical sensor 31 scans the light signal emitted by the grinding pad trimmed by the diamond dressing head, and receives the light signal reflected from the grinding pad. The diamond dressing head swings at a certain angle, and the grinding pad also rotates at the same time; the optical sensor is arranged on the outside of the diamond dressing head, and can basically scan the entire surface of the grinding pad. First of all, different materials absorb and reflect the light emitted by the optical sensor differently, and the signals generated are also different. Due to the different compositions of diamond particles and grinding liquid particles, the reflected spectra are also different, such as: different nitrogen peaks, etc. Therefore, according to the different spectral ranges, it is also possible to preliminarily judge whether diamonds have fallen. Secondly, because the size of diamonds and grinding fluid particles is quite different, generally speaking, the size of diamonds is at the micron level, while the size of grinding fluid particles is generally at the nanometer level. Therefore, the absorption and reflection of light signals by the two are quite different, and the intensity of light signals reflected back by the two is also quite different. Different particle sizes correspond to different light signal intensities. Therefore, according to the light signal intensity of the signal reflected back by the optical sensor, the particle size on the surface of the grinding pad can be judged. When the light signal intensity fluctuates greatly and exceeds the preset range, it can also be preliminarily judged that diamonds may have fallen.

[0040] like Figure 3 As shown in the figure, the optical signal data reflected from the polishing pad is illustrated as an example. The optical sensor performs real-time scanning and returns. Under normal circumstances, there will be contaminated particles and polishing liquid particles on the surface of the polishing pad, so the data reflected by the optical sensor will be in a fluctuating state. When a large abnormal fluctuation occurs and exceeds the preset range, such as part A in the figure, it can be preliminarily determined that a diamond may have fallen. Among them, the corresponding relationship between the reflected optical signal data and the particle size can be obtained based on the known particle size on the polishing pad and its corresponding optical signal data.

[0041] Please refer to Figure 2The image capture device 32 is arranged at the bottom of the container 13 to capture photos of the diamond trimming head before and after the work. According to the signal reflected by the optical sensor, it can be determined whether there are particles exceeding the preset size on the surface of the grinding pad, which may be fallen diamonds, but may also be other large particles. Therefore, the data obtained based on the optical sensor alone may not be accurate. On the basis of the optical sensor determining that there are larger particles and diamonds may have fallen, the image capture device can be combined to accurately determine whether diamonds have fallen. By comparing the photos of the diamond trimming head taken by the image capture device after the work with the photos taken before the work, it can be determined whether there is a problem of missing diamonds after the work (such as: it can be determined by comparing the number of diamonds on the diamond trimming head, and it can also be determined by comparing whether the diamond array has defects, etc.), and then it can be accurately determined whether diamonds have fallen.

[0042] The detection and processing part is connected to the optical sensor and the image capture device for communication, and is used to receive the data output by the optical sensor and the image capture device, and then process the data output by the optical sensor and the image capture device.

[0043] The detection and processing part can determine the particle size of the grinding pad based on the reflected light signal. When the particle size detected by the detection and processing part exceeds the preset value, it means that there may be diamonds dropped on the surface of the grinding pad. Whether diamonds have dropped can be further confirmed by combining the photos taken by the image shooting device. Specifically, whether diamonds have dropped during the operation of the diamond dresser can be determined by comparing the photos taken before and after the operation of the diamond dresser.

[0044] In one embodiment, when it is determined that a diamond may have fallen based on the light signal reflected back by the optical sensor, the operation is stopped immediately, which can effectively avoid the problem of a large number of wafers being scratched and scrapped in the future.

[0045] As an implementation method, the optical sensor 31 can be disposed at the front end of the diamond trimming head 11, please refer to Figure 4 .

[0046] As another embodiment, the optical sensor 31 can also be arranged on the side of the diamond trimming head 11, please refer to Figure 5 .

[0047] In one embodiment, there can be multiple optical sensors, and the multiple optical sensors can be distributed at different positions of the diamond dressing head, so that the scan is more comprehensive, and when one of the optical sensors fails, the remaining optical sensors can still transmit data back, and the failure rate is low.

[0048] In one embodiment, the optical sensor may be an infrared spectrum sensor.

[0049] Furthermore, the infrared spectrum sensor may be a miniaturized Fourier transform infrared spectrum sensor.

[0050] In one embodiment, it may further include: a fill light unit, which is used to perform fill light during the shooting process of the image shooting device.

[0051] In one embodiment, the container can be set as a transparent container, so that the image capture device has a better shooting angle and shooting environment, thereby achieving a better shooting effect.

[0052] In one embodiment, the storage container is a detachable structure.

[0053] Pragmatically, the detection and processing part may be a data analysis and processing module in a chemical mechanical polishing device.

[0054] It should be understood that the present invention mainly provides a monitoring device for a diamond dresser with an improved structure, wherein the detection and processing part can be implemented by circuits or electronic devices, and the software part that may be involved in its use is not an improvement of the present invention.

[0055] In the description of this specification, the description with reference to the terms "an implementation", "an example", "a specific implementation process", "an example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A monitoring device for a diamond dresser in a chemical mechanical polishing device, the diamond dresser comprising: A diamond trimming head, a swing arm and a storage container, wherein the diamond trimming head is located at one end of the swing arm; Before and after the diamond dresser works, the diamond dresser head is located in the container, and the monitoring device includes: An optical sensor, which is disposed outside the diamond dressing head and moves along with the movement of the diamond dresser. The optical sensor sends out a light signal to scan the grinding pad trimmed by the diamond dressing head and receives a light signal reflected from the grinding pad; An image shooting device is disposed at the bottom of the container to shoot pictures of the diamond trimming head before and after the diamond trimming head works; and The detection processing part is connected to the optical sensor and the image capturing device for processing the data output by the optical sensor and the image capturing device; wherein: The detection and processing part determines the particle size of the polishing pad according to the reflected light signal or determines its spectrum according to the reflected light signal; when the particle size detected by the detection and processing part exceeds a preset value or the spectrum detected by the detection and processing part is within a preset spectrum range, whether diamonds fall during the operation of the diamond dresser is monitored in combination with photos before and after the operation of the diamond dresser.

2. The monitoring device of the diamond dresser according to claim 1, characterized in that: The optical sensor is an infrared spectrum sensor.

3. The monitoring device of the diamond dresser according to claim 2, characterized in that: The infrared spectrum sensor is a miniaturized Fourier transform infrared spectrum sensor.

4. The monitoring device of the diamond dresser according to claim 1, characterized in that: The detection and processing part is a data analysis and processing module in the chemical mechanical polishing equipment.

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