CN111482903B

CN111482903B - Dresser for chemical mechanical polishing and chemical mechanical polishing device

Info

Publication number: CN111482903B
Application number: CN202010353220.8A
Authority: CN
Inventors: 许振杰; 王春龙
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2020-04-29
Filing date: 2020-04-29
Publication date: 2022-03-04
Anticipated expiration: 2040-04-29
Also published as: CN111482903A

Abstract

The invention discloses a dresser for chemical mechanical polishing and a chemical mechanical polishing device, wherein the dresser comprises a base assembly, a transmission shaft and a dressing assembly, the transmission shaft is coaxially arranged in the base assembly, and the dressing assembly is arranged at the lower side of the base assembly and rotates along with the transmission shaft; a magnetic sensor is arranged in the base component, a magnet is arranged in the trimming component, and the magnetic sensor detects the magnetic induction intensity of a magnetic field formed by the magnet so as to measure the position of the trimming component relative to the base component; the vertical distance between the magnetic sensor and the magnet is 2mm-10 mm.

Description

Dresser for chemical mechanical polishing and chemical mechanical polishing device

Technical Field

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a dresser for chemical mechanical polishing and a chemical mechanical polishing device.

Background

Chemical Mechanical Polishing (CMP) is an ultra-precise surface processing technique for global Planarization. The polishing method generally includes sucking a substrate on the lower portion of a carrier head, wherein one surface of the substrate with a deposition layer abuts against a rotating polishing pad, and the carrier head is driven by a driving part to rotate in the same direction as the polishing pad and apply downward load to the substrate; meanwhile, the polishing solution is supplied to the upper surface of the polishing pad and distributed between the substrate and the polishing pad, so that the substrate is subjected to global polishing under the combined action of chemistry and machinery.

In the chemical mechanical polishing process, in order to ensure good flatness and sharpness of the polishing pad and more contained grinding fluid to achieve efficient and stable grindability, a dressing device is used for dressing the polishing pad. Patent CN202479968U discloses a polishing pad dressing head and a polishing pad dresser having the same. The polishing pad conditioning head includes: a ring-shaped fixing member; the upper end of the guide shaft penetrates through the annular fixing piece, a first vent hole is formed in the wire guide shaft, and the first end and the second end of the first vent hole are communicated with the outside; an annular mounting member; the inner end of the flexible ring is hermetically arranged on the annular fixing piece, and the outer end of the flexible ring is hermetically arranged on the annular mounting piece; the inner end of the annular elastic disc is hermetically arranged on the guide shaft, and the outer end of the annular elastic disc is hermetically arranged on the annular mounting piece; and the clamping disc is fixed on the lower surface of the annular mounting part and is connected with the lower end of the guide shaft through a ball hinge, wherein the ball part of the ball hinge is arranged on the upper surface of the clamping disc, and the rod part of the ball hinge is connected with the lower end of the guide shaft. This patent enables pad conditioning, but does not incorporate a device for monitoring conditioner operation, does not enable closed loop conditioning, and optimizes the pad conditioning process based on the pad and other published conditions.

When the dressing device is used for dressing the polishing pad, a certain pressure needs to be applied, and the air path supply system is used for controlling the pressure of the internal cavity to adjust the grinding of the polishing pad, so that residual slurry in a gap is removed. Wherein the distance between the conditioning disk of the conditioning device and the polishing pad is directly related to the conditioning effect of the polishing pad. Therefore, it is necessary to monitor the height of the conditioning disk in real time, obtain the conditioning state of the polishing pad, and optimally adjust the conditioning process of the polishing pad according to the conditioning state of the polishing pad, so as to prolong the service life of the polishing pad and control the production cost of the chemical mechanical polishing.

Disclosure of Invention

The present invention aims to solve at least to some extent one of the technical problems existing in the prior art. To this end, the invention provides, in a first aspect, a dresser for chemical mechanical polishing, comprising a base assembly, a transmission shaft and a dresser assembly, wherein the transmission shaft is coaxially arranged in the base assembly, and the dresser assembly is arranged at the lower side of the base assembly and rotates along with the transmission shaft; a magnetic sensor is arranged in the base component, a magnet is arranged in the trimming component, and the magnetic sensor detects the magnetic induction intensity of a magnetic field formed by the magnet so as to measure the position of the trimming component relative to the base component; the vertical distance between the magnetic sensor and the magnet is 2mm-10 mm.

As a preferred embodiment, the base assembly comprises a base, the base is connected with the swing arm, the base is made of austenitic stainless steel, and the top of the base is provided with a groove for mounting the magnetic sensor.

As a preferred embodiment, the trimming assembly includes a protective cover, and a mounting hole is formed in the protective cover, and the magnet is bonded to the mounting hole.

As a preferred embodiment, the outer diameter of the magnet is matched with the inner diameter of the mounting hole, the bonding glue solution is filled between the magnet and the mounting hole, and the bonding glue solution on the outer periphery of the magnet is doped with anti-electromagnetic interference powder.

As a preferred embodiment, the magnet is a ferrite permanent magnet with a magnetic field grade of medium or strong magnetism.

As a preferred embodiment, the plurality of magnets form a magnetic induction of 0.2T to 2.5T.

As a preferred embodiment, the magneto-sensitive sensor can detect the change of magnetic induction intensity within the range of 0.01mm-20 mm.

As a preferred embodiment, the number of the magnetic sensors is multiple, and the magnetic sensors are uniformly distributed along the center of the base.

As a preferred embodiment, the anti-electromagnetic interference powder is silicon carbide, graphite and/or conductive fibers, and the doping volume ratio of the anti-electromagnetic interference powder is 10-30%.

In a second aspect, the invention provides a chemical mechanical polishing system comprising a polishing platen, a carrier head, a fluid supply, and a conditioning apparatus; wherein the dressing apparatus includes the above-described dresser.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: the position information of the trimming disc on the trimming assembly is accurately detected in real time, the morphology of the polishing pad is obtained, and the trimming control device can feed back and optimize the trimming process according to the position information of the trimming disc and the morphology of the polishing pad so as to prolong the service life of the polishing pad.

Drawings

The advantages of the invention will become clearer and more readily appreciated from the detailed description given with reference to the following drawings, which are given by way of illustration only, and which do not limit the scope of protection of the invention, wherein:

FIG. 1 is a schematic structural view of a dresser for chemical mechanical polishing according to the present invention;

FIG. 2 is a schematic view of the structure of the shield according to the present invention;

FIG. 3 is an exploded view of the shield and magnet of the present invention;

FIG. 4 is a schematic view of another embodiment of a conditioner for chemical mechanical polishing according to the present invention;

FIG. 5 is a schematic view of a chemical mechanical polishing apparatus according to the present invention.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following embodiments and accompanying drawings. The embodiments described herein are specific embodiments of the present invention for the purpose of illustrating the concepts of the invention; the description is intended to be illustrative and exemplary and should not be taken to limit the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification thereof, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of respective portions and their mutual relationships. It should be understood that the drawings are not necessarily to scale, the same reference numerals being used to identify the same elements in the drawings in order to clearly show the structure of the elements of the embodiments of the invention.

In the present invention, "Chemical Mechanical Polishing" is also referred to as "Chemical Mechanical Planarization (CMP)" and "substrate" is also referred to as "wafer", and the meaning and the actual function are equivalent.

Fig. 1 is a schematic structural view of a dresser 1 for chemical mechanical polishing according to the present invention, the dresser 1 for chemical mechanical polishing including a base assembly 10 and a dresser assembly 20. The base assembly 10 is fixed to the end of a swing arm of a finishing apparatus, not shown, and the finishing assembly 20 is provided to the lower side of the base assembly 10. The swing arm swings to drive the dressing assembly 20 to sweep within the radius of the polishing pad, so as to dress the surface of the polishing pad.

In fig. 1, a drive shaft 30 is provided inside the base assembly 10, an upper end of the drive shaft 30 is connected to a not-shown driving device of the dresser 1, and a lower end of the drive shaft 30 is connected to the dressing assembly 20. When the polishing pad is dressed, the dressing disk 21 located at the lower part of the dressing assembly 20 abuts against the polishing pad, the driving device drives the transmission shaft 30 to rotate, the transmission shaft 30 drives the dressing assembly 20 located at the lower side of the base assembly 10 to rotate, and the dressing disk 21 located at the bottom of the dressing assembly rotates along with the transmission shaft 30 to dress the surface of the polishing pad.

In order to know the dressing condition of the polishing pad, it is possible to monitor the positional information of the dressing disk 21 in the height direction on the lower portion of the dressing assembly 20. In order to monitor the change in positional information of the conditioning disc 21 in the height direction in real time, a sensor for detecting the positional information of the conditioning disc may be provided inside the conditioner 1.

In the embodiment shown in fig. 1, a magnetically sensitive sensor 40 is provided on base 11 of base assembly 10 and finishing assembly 20 is provided with a magnet 50. The magnet 50 is located within the vertical projection of the magnetic sensor 40. As the dresser 1 dresses the polishing pad, positional information of the dressing disk 21 in the height direction changes. The distance between magnet 50 of conditioning assembly 20 relative to magnetically sensitive sensor 40 also changes. Since the magnetic induction is related to the distance between the magnet 5 and the magnetic sensor 40, the magnetic induction detected by the magnetic sensor 40 changes as the height position of the conditioning disc 21 changes. The operator can judge the position change of the dressing disk 21 along the height direction according to the change of the magnetic induction intensity, obtain the dressing profile of the polishing pad, optimize and adjust the dressing process of the dresser, and prolong the service time of the polishing pad.

In the embodiment shown in fig. 1, the vertical distance between the magnetic sensor 40 and the magnet 50 should be no greater than 10mm, and should be no less than 2 mm. Preferably, the vertical distance between the magnetic sensor 40 and the magnet 50 is 8mm to ensure the detection accuracy of the magnetic sensor 40 and accurately acquire the position change of the conditioning disk 21 of the conditioning assembly 20.

Further, the magnetic sensor 40 is arranged on the top of the base 11, which is beneficial to leading out corresponding signal lines and power lines, effectively improves the convenience of dismounting and mounting the magnetic sensor 40, and facilitates the daily maintenance and overhaul of the dresser for chemical mechanical polishing.

In the embodiment shown in FIG. 1, the magneto-sensitive sensor 40 can detect changes in magnetic induction in the range of 0.01mm to 20 mm. Preferably, the optimal detection distance of the magnetic sensor 40 is related to the model of the corresponding magnetic sensor. The technician can determine the specific installation location of the magnet 50 and the magnetic sensor 40 according to the model of the magnetic sensor 40.

As an embodiment of the present invention, the magnetic sensor 40 may be a magnetic switch, which senses the strength of the magnetic field formed by the magnet 50 and triggers the reed-pull action to close the circuit. The circuit communicated in the magnetic switch can generate a current signal and transmit the current signal to the monitoring terminal so as to realize the monitoring of the position change of the trimming disk of the trimmer. As another embodiment of the present invention, the magneto-sensitive sensor 40 may alternatively be an analog type sensor, which may also detect the strength of the magnetic field. When the distance between the magnetic sensor 40 and the generated magnetic field changes, the magnetic induction intensity detected by the magnetic sensor 40 changes accordingly, and the voltage value output by the change in the magnetic induction intensity also changes accordingly. The position detection of the conditioning disk 21 can be realized by converting the voltage value corresponding to the magnetic induction.

In order to reduce the influence of external factors on the detection precision of the magnetic sensor 40, the base 11 provided with the magnetic sensor 40 is made of austenite steel or aluminum alloy. As an embodiment of the present invention, the base 11 may be made of austenitic stainless steel, so as to reduce the interference of ferrite material on the detection of the magnetic sensor 40 and ensure the accuracy of the detection of the magnetic sensor 40. It is understood that the base 11 and the internal components thereof may also be made of austenite or aluminum alloy, so as to avoid or reduce the use of ferrite-containing material as much as possible, so as to reduce the influence of external factors on the accuracy of the magnetic sensor 40. In some embodiments, the inner side wall of the base 11 is coated with an anti-electromagnetic interference coating, such as a tin foil layer, with a thickness of 0.1 μm to 2 μm, so as to prevent interference of metal components in the base 11 with the detection result and ensure the detection accuracy of the magnetic sensor 40.

Fig. 2 is a schematic structural view of the protection cover 20 according to the present invention, and the finishing assembly 20 includes the protection cover 22, and a plurality of magnets 50 are detachably disposed inside the protection cover 22. In one aspect of this embodiment, the magnet 50 is ferromagnetic in magnetic field level and is disposed within the shield 22. Fig. 2 is a cross-sectional view of the shield 22 containing a magnet 50, in this embodiment the magnet 50 is a cylindrical structure bonded within the mounting hole of the shield 22 by glue. Specifically, the mounting hole of the shield 22 is matched with the magnet 50, the outer diameter of the magnet 50 is slightly smaller than the inner diameter of the mounting hole of the shield 22, and the space between the magnet 50 and the mounting hole is filled with the adhesive. In some embodiments, the end surface and the cylindrical surface of the magnet 50 are coated with an adhesive solution to ensure the reliability of the fixation of the magnet 50. As an aspect of this embodiment, the adhesive glue solution located on the outer periphery of the magnet 50 is doped with anti-electromagnetic interference powder, where the anti-electromagnetic interference powder includes metal micro powder, barium chloride, silicon carbide, graphite, and/or conductive fiber, so as to prevent the external environment from affecting the detection accuracy of the magnetic sensor 40. The doping volume ratio of the anti-electromagnetic interference powder is not more than 30% and not less than 10%. Preferably, the anti-electromagnetic interference powder is conductive fiber, and the doping volume ratio of the conductive fiber is 15% so as to ensure the detection precision of the magnetic sensor 40.

Further, the magnetic field level of the magnet 50 may be a medium magnetic field. The magnets 50 of medium magnetic properties 50 are more densely arranged than the magnets 50 of stronger magnetic properties. As an embodiment of the present invention, the height of the magnet is 1mm to 30 mm. Preferably, the height of the magnet 50 is 15 mm.

Fig. 3 is an exploded view of the shield 22 including magnets 50, with the magnets 50 evenly spaced along the center of the shield 22. Magnets 50 are arranged in a uniform pattern to facilitate a substantially uniform magnetic field within conditioning assembly 20. When the dresser 1 is in operation, the dressing assembly 20 rotates relative to the base assembly 10, and the magnetic sensor 40 inside the base assembly 10 can detect the strength of the magnetic field formed by the magnet 50 inside the dressing assembly 20 in real time. The uniform arrangement of the magnets 50 can effectively avoid the influence of the nonuniformity of the magnetic field inside the trimming assembly 20 on the detection of the magnetic induction intensity, and ensure the accuracy of the position detection of the trimming disc.

In fig. 3, the number of the magnets 50 is 10, which are uniformly distributed inside the shield 22. It is understood that the number of magnets 50 may be other, such as 15, 18, etc., i.e., the number of magnets 50 may be an even number or an odd number. The denser the arrangement of the magnets 50, the stronger the magnetic field formed by the magnets 50 inside the conditioning assembly 20, and the more accurately the magnetic sensor 40 can detect the height variation of the conditioning disc 21 of the conditioner 1.

As an aspect of the present embodiment, the shield 22 is made of a non-metal material so as to reduce the influence of the metal material on the magnetic field formed by the plurality of magnets 50 and improve the accuracy of the magnetic induction detection. In some embodiments, the shield 22 may be made of Polytetrafluoroethylene (PTFE), which is chemically inert, enabling the use of a chemical mechanical polishing environment. It is understood that it may also be made of Polyethylene (PE), Polymethylmethacrylate (PMMA), Polycarbonate (PC), Polyurethane (PU), polypropylene (PP), Polystyrene (PS) and/or Polyoxymethylene (POM).

In the embodiment shown in fig. 3, magnet 50 may be a ferrite permanent magnet or a metal alloy magnet. Magnet 50 may be a ru-fe-b magnet, a samarium-co magnet, or an alnico magnet. The magnet 50 disposed inside the shield 22 forms a magnetic induction of 0.2T to 2.5T. Preferably, the magnet 50 disposed inside the shield 22 forms a magnetic induction of 1.25T.

The vertical distance between the top surface of the magnet 50 and the magnetic sensor 40 should be no greater than 30mm and no less than 5mm, and preferably, the vertical distance between the top surface of the magnet 50 and the bottom surface of the magnetic sensor 40 should be no greater than 20mm and no less than 5mm, so that the magnetic sensor 40 can accurately acquire the variation of the magnetic induction intensity of the trimming assembly 20 containing the magnet 50 and determine the variation of the height of the trimming disk 21.

Fig. 4 is a schematic view of another embodiment of the dresser for chemical mechanical polishing according to the present invention, in which the base assembly 10 includes a base 11 coupled to a swing arm of a dressing apparatus, and the base 11 is provided with a groove for mounting a magnetic sensor 40. The power line corresponding to the magnetic sensor 40 is led out from the upper part of the base 11 so as to provide power for the magnetic sensor 40.

As an aspect of this embodiment, the magnetic sensor 40 further includes a wireless transmission module, the magnetic sensor 40 transmits the acquired magnetic induction intensity data to the monitoring terminal through the wireless transmission module, and the monitoring terminal compares and analyzes the magnetic induction intensity data and optimizes and adjusts the trimming parameters of the trimmer 1. It is understood that the magnetic sensor 40 can also transmit the detection data to the monitoring terminal by wire.

Since the magnetic induction data acquired by each magnetic sensor 40 may be affected by the position factor and thus different, the number of the magnetic sensors 40 may be multiple, and the multiple magnetic sensors are disposed in the groove on the top of the base 11. The data measured by each magnetic sensor 40 is processed averagely or weighted averagely, so that the interference of external factors on the magnetic induction intensity detection can be filtered out, and the accuracy of measurement is ensured.

FIG. 5 is a schematic view of a chemical mechanical polishing apparatus 100 according to the present invention, which includes a polishing platen 6, a carrier head 5, a liquid supply device 4, and a dressing device 2; wherein the dressing apparatus 2 includes the above-described dresser 1. The dresser 1 is provided on a swing arm of the dressing apparatus, and the dresser 1 rotates to dress the polishing pad 3 on the polishing disk 6. During the dressing process of the dresser 1, the position change of the dressing assembly 20 and the base assembly 10 can be determined through the magnetic induction intensity obtained by the magnetic sensor 40, that is, the position of the dressing disk 21 relative to the polishing pad 3 shown in fig. 1 is obtained, and the topography of the polishing pad 3 is obtained on line in real time, so as to further optimize and adjust the dressing process of the polishing pad and prolong the service life of the polishing pad.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A dresser for chemical mechanical polishing comprises a base assembly, a transmission shaft and a dressing assembly, wherein the base assembly comprises a base, the transmission shaft is coaxially arranged in the base assembly, and the dressing assembly is arranged on the lower side of the base assembly and rotates along with the transmission shaft; the trimming device is characterized in that a magnetic sensor is arranged in the base component, a magnet is arranged in the trimming component, and the magnetic sensor detects the magnetic induction intensity of a magnetic field formed by the magnet so as to measure the position of the trimming component relative to the base component; the vertical distance between the magnetic sensor and the magnet is 2mm-10 mm; the number of the magnets is multiple, and the magnets are uniformly distributed along the center of the protective cover of the trimming assembly; the number of the magnetic sensors is multiple, the magnetic sensors are uniformly distributed along the center of the base and are positioned in the groove in the top of the base, and the pose of the trimming disc of the trimming assembly is obtained through mutual induction of the magnetic sensors and the magnet; the inside of the protective cover is provided with a mounting hole, and the magnet is bonded to the mounting hole; the outer diameter of the magnet is matched with the inner diameter of the mounting hole, a bonding glue solution is filled between the magnet and the mounting hole, and the bonding glue solution positioned on the outer peripheral side of the magnet is doped with anti-electromagnetic interference powder; the magnet is located within the vertical projection range of the magnetic sensor.

2. A dresser according to claim 1, wherein the base is made of austenitic stainless steel and is provided at a top thereof with a recess in which the magnetic sensor is mounted.

3. The dresser of claim 1, wherein the magnet is a ferrite permanent magnet having a magnetic field rating of medium or strong magnetism.

4. The dresser of claim 1, wherein the plurality of magnets form a magnetic induction of 0.2T to 2.5T.

5. A conditioner in accordance with claim 2 wherein said magnetic sensor senses changes in magnetic induction in the range of 0.01mm to 20 mm.

6. A conditioner in accordance with claim 1, wherein said emi resistant powder is silicon carbide, graphite and/or conductive fibers doped in a volume ratio of 10% to 30%.

7. A chemical mechanical polishing device comprises a polishing disk, a bearing head, a liquid supply device and a finishing device; characterized in that the dressing apparatus comprises the dresser of any one of claims 1 to 6.