CN117300884A - Detection device and detection method for chemical mechanical polishing end point - Google Patents
Detection device and detection method for chemical mechanical polishing end point Download PDFInfo
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- CN117300884A CN117300884A CN202311475173.4A CN202311475173A CN117300884A CN 117300884 A CN117300884 A CN 117300884A CN 202311475173 A CN202311475173 A CN 202311475173A CN 117300884 A CN117300884 A CN 117300884A
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- 238000005498 polishing Methods 0.000 title claims abstract description 195
- 239000000126 substance Substances 0.000 title claims abstract description 81
- 238000001514 detection method Methods 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 claims abstract description 55
- 238000012545 processing Methods 0.000 claims abstract description 26
- 239000002184 metal Substances 0.000 claims description 48
- 229910052751 metal Inorganic materials 0.000 claims description 48
- 230000008569 process Effects 0.000 claims description 26
- 230000000737 periodic effect Effects 0.000 claims description 3
- 238000007517 polishing process Methods 0.000 abstract description 16
- 230000008859 change Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 238000001914 filtration Methods 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
- B24B37/013—Devices or means for detecting lapping completion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/14—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the temperature during grinding
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- Mechanical Engineering (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Abstract
The invention relates to the technical field of chemical mechanical polishing, and discloses a device and a method for detecting a chemical mechanical polishing end point, wherein the device comprises: the high-frequency alternating magnetic field generator is fixed at a preset position of a polishing disk for chemically and mechanically polishing a wafer through rotation and rotates together with the polishing disk, and is used for generating an alternating magnetic field, and when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat; the temperature detector is fixed at a preset position of the high-frequency alternating magnetic field generator, rotates together with the polishing disk and is used for detecting the temperature of the polished surface when the wafer is periodically scanned; and the data processing module is used for judging whether the chemical mechanical polishing reaches the end point according to the temperature. According to the invention, the polishing end point is detected by the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, and the polishing quality is ensured.
Description
Technical Field
The invention relates to the technical field of chemical mechanical polishing, in particular to a device and a method for detecting a chemical mechanical polishing end point.
Background
Chemical mechanical polishing (CMP, chemical Mechanical Polishing) technology plays an important role in the large scale integrated circuit multi-layer interconnect process. The polishing process for each layer is to remove the protruding portion of each layer uniformly, a small amount and continuously to make the protruding portion even, but the thickness of the removed film needs to be controlled with high precision, and if the CMP operation cannot be monitored effectively, the wafer polishing will be excessive or insufficient. CMP endpoint detection is a critical step for integrated circuit yield.
The end point detection has various forms, such as optical, electrical, acoustic, thermal, friction force, chemical and the like, and has the characteristics of the end point detection, but has certain limitations, the most widely used and mature method for metal polishing end point detection is still optical detection at present, the polished surface is irradiated by light with a certain wavelength, and the end point is detected by the change of the reflection intensity due to the different reflection intensities of different media.
The optical endpoint detection system is complex and expensive in construction, and during the polishing process, due to the presence of the polishing liquid, the relative rotation of the polishing head and the polishing disk, the swinging of the polishing head, etc., all introduce a large number of invalid and noise signals, so that a large number of filtering and calculation are required when the receiving end receives the reflected light beam, which may cause the problem that the polishing endpoint cannot be detected, resulting in over polishing, thereby causing serious product quality problems.
In addition, in the prior art, temperature detection is carried out according to the temperature generated by hardware friction, chemical reaction and the like in the chemical mechanical polishing process, and the result has serious hysteresis, in addition, because the temperature near the polishing head is detected as a judgment basis, the actual polishing result of the polished surface cannot be well quantitatively detected, and only qualitative detection can be carried out by means of prediction and verification of a large number of experiments, the polishing end point detection is inaccurate, and over polishing is caused, so that serious product quality problems are caused.
Disclosure of Invention
In view of the above, the present invention provides a device and a method for detecting a chemical mechanical polishing endpoint, so as to solve the problem of inaccurate detection of the chemical mechanical polishing endpoint in the prior art.
In a first aspect, the present invention provides an apparatus for detecting a chemical mechanical polishing endpoint, the apparatus comprising:
the high-frequency alternating magnetic field generator is fixed at a preset position of a polishing disk for chemically and mechanically polishing a wafer through rotation and rotates together with the polishing disk, and is used for generating an alternating magnetic field, and when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat;
the temperature detector is fixed at a preset position of the high-frequency alternating magnetic field generator, rotates together with the polishing disk and is used for detecting the temperature of the polished surface when the wafer is periodically scanned;
and the data processing module is used for receiving the temperature detected by the temperature detector and judging whether the chemical mechanical polishing reaches the end point or not according to the temperature.
According to the detection device for the chemical mechanical polishing end point, provided by the embodiment of the invention, the high-frequency alternating magnetic field generator and the temperature detector are driven to rotate together in the process of carrying out chemical mechanical polishing on a wafer by rotating the polishing disk, the high-frequency alternating magnetic field generator generates an alternating magnetic field in the rotating process, when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat, meanwhile, the temperature detector detects the temperature of the polished surface, and the data processing module judges whether the chemical mechanical polishing end point is reached or not according to the received temperature. According to the invention, the polishing end point is detected by the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, and the polishing quality is ensured.
In an alternative embodiment, the high frequency alternating magnetic field generator is fixedly arranged along the radial direction of the polishing disk.
According to the invention, the high-frequency alternating magnetic field generator is arranged in the radial direction of the polishing disk, and the temperature detector is fixed on the high-frequency alternating magnetic field generator, so that the high-frequency alternating magnetic field generator and the temperature detector are driven to rotate together in the process of polishing the wafer by rotating the polishing disk, the wafer is periodically scanned, the alternating magnetic field generates heat on the polished surface of the wafer in each scanning, meanwhile, the temperature of the polished surface is detected, the polishing end point can be further judged by the temperature, and the influence of detection environment is avoided.
In an alternative embodiment, the scanning range of the high-frequency alternating magnetic field generator and the detection range of the temperature detector are not smaller than the diameter of the wafer.
The invention can detect the polished surface of the whole wafer by ensuring that the working ranges of the high-frequency alternating magnetic field generator and the temperature detector are not smaller than the diameter of the wafer, thereby further improving the polishing quality.
In a second aspect, the present invention provides a method for detecting a chemical mechanical polishing endpoint, based on detecting a chemical mechanical polishing endpoint, the method comprising:
the high-frequency alternating magnetic field generator generates an alternating magnetic field in the process of chemically and mechanically polishing the wafer by rotating the polishing disk, and when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat;
the temperature detector detects the temperature of the polished surface when the wafer is periodically scanned in the rotation process of the polishing disk, and sends the temperature to the data processing module;
the data processing module receives the temperature and judges whether the chemical mechanical polishing reaches the end point according to the temperature.
According to the method for detecting the chemical mechanical polishing end point, the high-frequency alternating magnetic field generator and the temperature detector are driven to rotate together in the process of carrying out chemical mechanical polishing on the wafer by rotating the polishing disc, the high-frequency alternating magnetic field generator generates an alternating magnetic field in the rotating process, when the alternating magnetic field periodically scans the polished surface of the wafer, heat is generated by the polished surface, meanwhile, the temperature detector detects the temperature of the polished surface, and the data processing module judges whether the chemical mechanical polishing end point is reached or not according to the received temperature. According to the invention, the polishing end point is detected by the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, and the polishing quality is ensured.
In an alternative embodiment, the high frequency alternating magnetic field generator and the temperature detector are in a normally open state during rotation of the polishing platen.
According to the invention, the alternating magnetic field is continuously generated and the temperature detection is continuously carried out in the polishing process, and when the high-frequency alternating magnetic field generator and the temperature detector rotate along with the polishing disk and scan the wafer, heat can be rapidly generated and temperature change caused by the heat can be rapidly detected, so that the hysteresis of the traditional temperature detection is solved.
In an alternative embodiment, the surface being polished is subjected to a constant heat generated by chemical mechanical polishing.
In the chemical mechanical polishing process, constant heat is generated due to friction between the polishing disk and the wafer, namely, the polished surface of the wafer is stabilized at a fixed temperature, and temperature transformation caused by eddy current can be introduced on the basis of the temperature, so that the polishing end point is judged according to the temperature change.
In an alternative embodiment, the process of generating heat from a polished surface of a wafer as an alternating magnetic field is scanned over the polished surface includes: the alternating magnetic field periodically scans the wafer in the process of rotating along with the polishing disk; in the same periodic scanning process, when the alternating magnetic field scans the wafer, if metal exists on the surface to be polished, the metal forms vortex to enable the surface to be polished to generate heat, and the temperature rises; after the alternating magnetic field scans the wafer, the polished surface has no vortex and the temperature is reduced.
According to the invention, the high-frequency alternating magnetic field generator continuously generates the alternating magnetic field, the polishing disk is driven to periodically scan the wafer, when the metal is scanned, the metal is in the alternating magnetic field to form eddy current so as to generate heat, and after the metal is scanned, the heat is not generated any more, so that the temperature of the wafer rises and falls regularly in one scanning period, and the temperature change generated by the eddy current can be used as a detection signal, so that the influence of the inspection environment is avoided.
In an alternative embodiment, when the alternating magnetic field scans to the wafer, the method further comprises: if the polished surface does not contain metal, the metal does not form vortex, the polished surface does not generate heat caused by the vortex, and the temperature is unchanged.
The metal on the polished surface of the wafer is polished by rotating the polishing disk, and one circle of metal is polished out of one part of metal in each rotation. The alternating magnetic field can form eddy current in the metal only when the metal exists, and generates heat, so that the eddy current can not be generated after the metal does not exist on the polished surface, the temperature is unchanged, and whether the polishing reaches the end point can be judged through the temperature.
In an alternative embodiment, the process of determining whether the chemical mechanical polishing reaches an endpoint based on temperature includes: when the temperature is stabilized at a temperature corresponding to the constant heat generated by the chemical mechanical polishing within a preset time period, no metal exists on the polished surface, and the chemical mechanical polishing reaches an end point.
According to the invention, the wafer is periodically polished through rotation of the polishing disk, so that the metal on the polished surface is gradually polished, the eddy current formed by the alternating magnetic field is weaker and weaker each time, the temperature of the polished surface is lower and lower each time, and finally, the metal is completely polished, only constant heat is generated due to chemical mechanical polishing, the temperature tends to be stable at the moment, so that whether the polished end point is reached can be judged by judging whether the temperature tends to be stable or not, the temperature parameter is less influenced by the polishing environment, and the filtering and the calculation are not needed by a complex algorithm.
In an alternative embodiment, after the data processing module receives the temperature, the method further comprises: and displaying the temperatures of different positions of the polished surface according to a preset mode.
The invention can intuitively judge whether the metal on the surface of the wafer is polished or not according to the polishing conditions of the wafer by detecting the temperature of the whole polished surface of the wafer and reflecting the temperatures of different positions.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a light source scan path according to an embodiment of the present invention;
FIG. 2 is a block diagram of a chemical mechanical polishing end point detection apparatus according to an embodiment of the present invention;
FIG. 3 is a flow chart of a method for detecting a chemical mechanical polishing endpoint according to an embodiment of the invention;
FIG. 4 is a schematic view of a scanning area of a method for detecting a chemical mechanical polishing endpoint according to an embodiment of the invention;
FIG. 5 is a flow chart of another method for detecting a chemical mechanical polishing endpoint according to an embodiment of the invention;
FIG. 6 is a schematic diagram of temperature variation of another method for detecting a chemical mechanical polishing endpoint in accordance with an embodiment of the present invention;
fig. 7 is a schematic diagram showing a temperature of another method for detecting a chemical mechanical polishing endpoint according to an embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The embodiment of the invention is suitable for the scene of chemically and mechanically polishing the surface metal of the wafer. In the chemical mechanical polishing process required for integrated circuit fabrication, it is often desirable to provide an endpoint detection system (End Point Detector, EPD) to increase the process window and more effectively control the process. The working principle of the EPD device in the chemical mechanical polishing system at present mainly comprises modes of optics, vortex, driving motor current, temperature, products and the like; among the most common and most effective are optical detection means. The structure and data processing of optical detection are complex, during the polishing process, due to the existence of the polishing liquid, the relative rotation of the polishing head and the polishing disc, the swinging of the polishing head, etc., all of which can introduce a large amount of invalid and noise signals, so that a large amount of filtering and operation are needed when the receiving end receives the reflected light beam, the problem that the polishing endpoint cannot be detected may occur, in addition, due to the smaller incident light beam, the information of the whole surface cannot be collected when the wafer surface is irradiated, and the serious problems such as metal residues may occur after the endpoint detection is finished, as shown in the schematic diagram of the scanning path of the light source on the wafer surface in fig. 1, the scanning path represents that the scanning path of the rotation and swinging of the polishing disc and the polishing head is more complex only under the condition that the polishing disc rotates.
Therefore, the embodiment of the invention provides a detection device for a chemical mechanical polishing end point, which can achieve the effect of accurately judging the polishing end point by detecting the temperature change of the surface of a wafer caused by vortex. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function.
The embodiment of the invention provides a device for detecting a chemical mechanical polishing end point, as shown in fig. 2, a system comprises:
a high-frequency alternating magnetic field generator 201 fixed at a preset position of a polishing disk for performing chemical mechanical polishing on a wafer by rotation and rotating together with the polishing disk for generating an alternating magnetic field, and generating heat on a polished surface of the wafer when the alternating magnetic field periodically scans the polished surface;
a temperature detector 202 fixed at a preset position of the high-frequency alternating magnetic field generator and rotated together with the polishing disk, for detecting the temperature of the polished surface when the wafer is periodically scanned;
the data processing module 203 is configured to receive the temperature detected by the temperature detector, and determine whether the chemical mechanical polishing reaches an endpoint according to the temperature.
Specifically, in an embodiment of the present invention, the process control of chemical mechanical polishing comprises three steps: removing a large amount of metal on the surface of a wafer, and leaving a small amount of metal; the second step, completely removing the metal on the surface of the wafer and exposing the barrier layer; and thirdly, completely removing the blocking layer to expose the dielectric layer. The polishing endpoint detection of the embodiments of the present invention is directed to the second step of detecting whether the metal on the wafer surface is completely polished. The polishing disk is a main component of the conventional chemical mechanical polishing device, the chemical mechanical polishing device fixes a wafer to be polished on the polishing head, so that the polishing disk is in contact with the polished surface of the wafer, the polished surface of the wafer is polished by rotating, meanwhile, the polishing disk is provided with polishing liquid, and the polishing head drives the wafer to rotate in situ, so that the metal on the polished surface of the wafer is continuously mechanically polished and chemically corroded.
In an alternative embodiment, as shown in fig. 2, the embodiment of the present invention fixes the high-frequency alternating magnetic field generator 201 at a preset position on the polishing disk, and fixes the temperature detector 202 at a preset position of the high-frequency alternating magnetic field generator 201. In the embodiment of the present invention, the high-frequency alternating magnetic field generator 201 is fixedly arranged along the radial direction of the polishing disc, and the temperature detector 202 is fixed at the upper center position of the high-frequency alternating magnetic field generator 201 and is integrated with the high-frequency alternating magnetic field generator 201, but not limited thereto. During polishing, the high frequency alternating magnetic field generator 201 and the temperature detector 202 rotate with the polishing platen, and thus can periodically scan to a wafer in a fixed position. The high-frequency alternating magnetic field generator 201 generates an alternating magnetic field during rotation, and causes the polished surface of the wafer to generate heat when the alternating magnetic field periodically scans the polished surface, and at the same time, the temperature detector 202 detects the temperature of the polished surface.
In an alternative embodiment, in order to ensure that the whole polished surface of the wafer can be scanned and detected, the scanning range of the high-frequency alternating magnetic field generator 201 and the detection range of the temperature detector 202 adopted in the embodiment of the invention are not smaller than the diameter of the wafer, and the temperature generated by the eddy current drops rapidly due to the short time of each scanning of the wafer by the detection device and the existence of the grinding fluid, so that the temperature detection by the high-sensitivity temperature detector is selected to better capture the change of the temperature, which is only by way of example and not by way of limitation.
In an alternative implementation manner, the data processing module 203 is integrated on the high-frequency alternating magnetic field generator 201, the temperature detected by the temperature detector 202 is sent to the data processing module 203 in a wired manner, or is sent to the data processing module 203 outside the polishing disc in a wireless manner, but not limited to this, then the data processing module 203 determines whether the polishing reaches the end point according to the temperature, and stops polishing if the polishing reaches the end point.
According to the detection device for the chemical mechanical polishing end point, provided by the embodiment of the invention, the high-frequency alternating magnetic field generator and the temperature detector are driven to rotate together in the process of carrying out chemical mechanical polishing on a wafer by rotating the polishing disk, the high-frequency alternating magnetic field generator generates an alternating magnetic field in the rotating process, when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat, meanwhile, the temperature detector detects the temperature of the polished surface, and the data processing module judges whether the chemical mechanical polishing end point is reached or not according to the received temperature. According to the invention, the polishing end point is detected by the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, and the polishing quality is ensured.
The embodiment of the invention provides a method for detecting a chemical mechanical polishing end point, which can achieve the effect of accurately judging the polishing end point by detecting the temperature change of the surface of a wafer caused by vortex. It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.
In this embodiment, a method for detecting a chemical mechanical polishing endpoint is provided, which may be used in the computer, and fig. 3 is a flowchart of a method for detecting a chemical mechanical polishing endpoint according to an embodiment of the present invention, as shown in fig. 3, where the flowchart includes the following steps:
in step S301, the high-frequency alternating magnetic field generator generates an alternating magnetic field during the chemical mechanical polishing of the wafer by rotating the polishing disk, and generates heat when the alternating magnetic field periodically scans the polished surface of the wafer.
Specifically, in the embodiment of the present invention, during the chemical mechanical polishing process of the polished surface of the wafer by rotating the polishing disk, the high-frequency alternating magnetic field generator 201 is driven to rotate together, and the high-frequency alternating magnetic field generator 201 is in a normally open state, so as to continuously generate the high-frequency alternating magnetic field, as shown in fig. 4, the shaded portion is a scanning area through which the high-frequency alternating magnetic field generator 201 rotates for one circle. Therefore, the polishing disk drives the wafer to rotate, and the high-frequency alternating magnetic field can periodically scan the polished surface of the wafer. When the alternating magnetic field periodically scans the surface to be polished, the surface to be polished can quickly form eddy due to the existence of metal, so that heat is generated on the metal of the surface to be polished.
In step S302, the temperature detector detects the temperature of the polished surface when the wafer is periodically scanned during the rotation of the polishing disk, and sends the temperature to the data processing module.
Specifically, in the embodiment of the present invention, since the high-frequency alternating magnetic field generator 201 and the temperature detector 202 are fixed as a unit, when the high-frequency alternating magnetic field generator 201 rotates with the polishing pad, the temperature detector 202 also rotates together. Therefore, when the high-frequency alternating magnetic field generator 201 periodically scans the wafer along with the rotation of the polishing disk and generates heat on the surface of the wafer, the temperature detector 202 is also periodically positioned at the wafer position and detects the temperature of the polished surface of the wafer. The temperature detector 202 transmits the detected temperature to the data processing module 203 for further analysis in real time, but not limited thereto.
In step S303, the data processing module receives the temperature and determines whether the chemical mechanical polishing reaches the endpoint according to the temperature.
Specifically, in the embodiment of the present invention, the high frequency alternating magnetic field generator 201 and the temperature detector 202 rotate with the polishing platen and periodically scan and temperature detect the wafer. As the metal on the polished surface of the wafer is continuously polished, the heat generated by the polished surface is gradually reduced, so that the data processing module 203 can determine whether the chemical mechanical polishing reaches the end point according to the received temperature. The polishing endpoint is judged by utilizing the temperature, the influence of the polishing environment can be avoided, the judging process is simple, and the filtering and the calculation are not required to be carried out by a complex algorithm.
According to the method for detecting the chemical mechanical polishing end point, the high-frequency alternating magnetic field generator and the temperature detector are driven to rotate together in the process of carrying out chemical mechanical polishing on the wafer by rotating the polishing disc, the high-frequency alternating magnetic field generator generates an alternating magnetic field in the rotating process, when the alternating magnetic field periodically scans the polished surface of the wafer, heat is generated by the polished surface, meanwhile, the temperature detector detects the temperature of the polished surface, and the data processing module judges whether the chemical mechanical polishing end point is reached or not according to the received temperature. According to the invention, the polishing end point is detected by the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, and the polishing quality is ensured.
In this embodiment, a method for detecting a chemical mechanical polishing endpoint is provided, which may be used in the computer, and fig. 5 is a flowchart of a method for detecting a chemical mechanical polishing endpoint according to an embodiment of the present invention, as shown in fig. 5, where the flowchart includes the following steps:
in step S501, the high-frequency alternating magnetic field generator generates an alternating magnetic field during the chemical mechanical polishing of the wafer by rotating the polishing disk, and generates heat when the alternating magnetic field periodically scans the polished surface of the wafer.
Specifically, the step S501 includes:
in step S5011, the alternating magnetic field periodically scans the wafer during rotation of the polishing disk. Please refer to step S301 in the embodiment shown in fig. 3 in detail, which is not described herein.
In step S5012, when the wafer is scanned by the alternating magnetic field during the same periodic scanning, if the metal exists on the surface to be polished, the metal forms an eddy current to generate heat on the surface to be polished, and the temperature rises.
Specifically, in the embodiment of the invention, during the chemical mechanical polishing of the polished surface of the wafer by the rotation of the polishing disk, the metal of the polished surface is gradually reduced. The alternating magnetic field only forms eddy current when metal exists, and the eddy current can enable the metal to generate heat. Therefore, when the polished layer is still provided with metal, eddy currents are formed when the alternating magnetic field scans the polished layer, and the temperature of the polished surface is increased.
In an alternative embodiment, the heat generated by the polished surface includes not only eddy current induced heat, but also constant heat generated by the physical friction and chemical reaction of the chemical mechanical polishing.
In step S5013, after the wafer is scanned by the alternating magnetic field, the polished surface has no eddy current, and the temperature is reduced.
Specifically, in the embodiment of the present invention, when the high-frequency alternating magnetic field generator 201 rotates through the wafer, the temperature of the polished layer of the wafer rapidly rises due to the presence of the alternating magnetic field, and after scanning, the temperature rapidly drops due to the absence of eddy currents. According to the embodiment of the invention, the wafer is periodically scanned, so that the temperature of the polished surface of the wafer is repeatedly increased and decreased. And although there is no heat caused by the eddy current after scanning, since the chemical mechanical polishing is always present, the lowest temperature detected by the temperature detector 202 is a constant temperature corresponding to a constant heat generated by the chemical mechanical polishing.
In step S5014, if no metal exists on the surface to be polished, no eddy current is formed on the surface to be polished, and no heat is generated on the surface to be polished due to the eddy current, and the temperature is unchanged.
Specifically, in the embodiment of the invention, the metal on the polished surface of the wafer is gradually reduced by continuously polishing the polishing disc, and after the metal is thoroughly polished, eddy current is not formed when the alternating magnetic field periodically scans the wafer, and the temperature of the polished surface is not increased.
In step S502, the temperature detector detects the temperature of the polished surface when the wafer is periodically scanned during the rotation of the polishing disk, and sends the temperature to the data processing module. Please refer to step S302 in the embodiment shown in fig. 3 in detail, which is not described herein.
In step S503, the data processing module receives the temperature, and determines whether the chemical mechanical polishing reaches the endpoint according to the temperature.
Specifically, the step S503 includes:
in step S5031, when the temperature is stabilized at a temperature corresponding to the constant heat generated by the chemical mechanical polishing for a predetermined period of time, the polished surface is free of metal, and the chemical mechanical polishing reaches the end point.
Specifically, in the embodiment of the invention, after the metal on the polished surface of the wafer is thoroughly polished gradually, heat caused by eddy current is not generated when the alternating magnetic field is scanned to the polished surface again, and only a constant temperature corresponding to constant heat generated by physical friction and chemical reaction of chemical mechanical polishing is remained at the detected temperature. The temperature detected by the temperature detector 202 received by the data processing module 203 is thus as shown in fig. 6: in the initial stage, the metal on the polished surface is thicker, the temperature rises during the period of scanning, the scanning is finished, the temperature is reduced, and the process is repeated; the second stage, the metal part is polished gradually, and the highest temperature is reduced gradually during each scanning; and in the third stage, the metal part is polished, and the temperature after each scanning is fixed, wherein the temperature is caused by heat generated in the chemical mechanical polishing process. According to the embodiment of the invention, when the temperature tends to be stable within the preset time period, the chemical mechanical polishing is judged to reach the end point, and the polishing is stopped. The predetermined period of time according to the embodiment of the present invention is determined according to the polishing process, for example, copper polishing is generally 10s-20s, which is only used as an example and not limited thereto.
Step S5032, displaying the temperatures of different positions of the polished surface according to a preset mode.
Specifically, in the embodiment of the present invention, the temperature detector 202 can detect the temperatures of different positions of the whole polished surface, and the temperatures can represent the polishing conditions of the metal, so that the embodiment of the present invention uses different colors to represent the temperatures of the polished surface of the wafer, and according to the graph, whether the metal of the polished surface is polished can be intuitively determined, as shown in fig. 7, by way of example only, and not by way of limitation.
According to the method for detecting the chemical mechanical polishing end point, provided by the embodiment of the invention, the polishing end point is detected through the temperature, so that the influence of the detection environment on the temperature in the polishing process can be avoided, the accuracy of polishing end point detection is improved, the polishing quality is ensured, the judging process is simple and easy to realize, and complex algorithm support is not needed.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.
Claims (10)
1. A chemical mechanical polishing endpoint detection apparatus, comprising:
the high-frequency alternating magnetic field generator is fixed at a preset position of a polishing disk for chemically and mechanically polishing a wafer through rotation and rotates together with the polishing disk, and is used for generating an alternating magnetic field, and when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat;
the temperature detector is fixed at a preset position of the high-frequency alternating magnetic field generator, rotates together with the polishing disk and is used for detecting the temperature of the polished surface when the wafer is periodically scanned;
and the data processing module is used for receiving the temperature detected by the temperature detector and judging whether the chemical mechanical polishing reaches an end point or not according to the temperature.
2. The apparatus according to claim 1, wherein the high-frequency alternating magnetic field generator is fixedly disposed along a radial direction of the polishing disk.
3. The apparatus of claim 2, wherein a scanning range of the high frequency alternating magnetic field generator and a detection range of the temperature detector are not smaller than a diameter of the wafer.
4. A method for detecting a chemical mechanical polishing endpoint, wherein the method is based on the apparatus of claims 1-3, and comprises:
the high-frequency alternating magnetic field generator generates an alternating magnetic field in the process of chemically and mechanically polishing a wafer by rotating a polishing disk, and when the alternating magnetic field periodically scans the polished surface of the wafer, the polished surface generates heat;
the temperature detector detects the temperature of the polished surface when the wafer is periodically scanned in the rotation process of the polishing disk, and sends the temperature to the data processing module;
the data processing module receives the temperature and judges whether the chemical mechanical polishing reaches an end point or not according to the temperature.
5. The method of claim 4, wherein the high frequency alternating magnetic field generator and the temperature detector are in a normally open state during rotation of the polishing platen.
6. The method of claim 4, further comprising, during chemical mechanical polishing of the wafer by rotation of the polishing platen:
the polished surface generates constant heat by chemical mechanical polishing.
7. The method according to claim 5 or 6, wherein the process of generating heat from the polished surface of the wafer when the alternating magnetic field is scanned onto the polished surface comprises:
the alternating magnetic field periodically scans the wafer in the process of rotating along with the polishing disk;
in the same periodic scanning process, when the alternating magnetic field scans the wafer, if metal exists on the surface to be polished, the metal forms eddy current to enable the surface to be polished to generate heat, and the temperature rises; after the alternating magnetic field scans the wafer, the polished surface has no vortex and the temperature is reduced.
8. The method of claim 7, wherein when the alternating magnetic field is scanned to the wafer, further comprising:
if the polished surface does not contain metal, the polished surface does not form eddy current, the polished surface does not generate heat caused by the eddy current, and the temperature is unchanged.
9. The method of claim 8, wherein said determining whether the chemical mechanical polishing has reached an endpoint based on the temperature comprises:
and when the temperature is stabilized at a temperature corresponding to constant heat generated by chemical mechanical polishing in a preset time period, the polished surface is free of metal, and the chemical mechanical polishing reaches an end point.
10. The method of claim 4, wherein after the data processing module receives the temperature, further comprising: and displaying the temperatures of different positions of the polished surface according to a preset mode.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311475173.4A CN117300884A (en) | 2023-11-07 | 2023-11-07 | Detection device and detection method for chemical mechanical polishing end point |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311475173.4A CN117300884A (en) | 2023-11-07 | 2023-11-07 | Detection device and detection method for chemical mechanical polishing end point |
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| CN117300884A true CN117300884A (en) | 2023-12-29 |
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| CN202311475173.4A Pending CN117300884A (en) | 2023-11-07 | 2023-11-07 | Detection device and detection method for chemical mechanical polishing end point |
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| Country | Link |
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| CN (1) | CN117300884A (en) |
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- 2023-11-07 CN CN202311475173.4A patent/CN117300884A/en active Pending
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