CN116637873A

CN116637873A - Cleaning method of chemical mechanical polishing retaining ring

Info

Publication number: CN116637873A
Application number: CN202310625381.1A
Authority: CN
Inventors: 惠宏业; 姚力军; 许慷; 左威; 赵梓聿; 柏钧天
Original assignee: Ningbo Runping Electronic Materials Co ltd
Current assignee: Ningbo Runping Electronic Materials Co ltd
Priority date: 2023-05-30
Filing date: 2023-05-30
Publication date: 2023-08-25

Abstract

The invention provides a cleaning method of a chemical mechanical polishing retaining ring, which comprises the steps of carrying out pure water showering, cleaning and digging washing by adopting a cleaning agent and secondary pure water showering in sequence before ultrasonic cleaning, so that a threaded hole positioned on an SUS surface can be effectively ensured to be soaked by pure water first, then is dug and washed, and then is flushed by pure water at least once, black attachments at the bottom of the threaded hole can be effectively removed, the cleaning method is suitable for standardized operation of batch products, and the product quality and the product processing efficiency can be improved; in addition, the cleaning method adopts various types of cleaning, carries out all-round cleaning operation on the chemical mechanical polishing retaining ring, improves the cleaning quality and the cleaning effect of the chemical mechanical polishing retaining ring, and further prevents the wafer from being polluted by the chemical mechanical polishing retaining ring in the using process.

Description

Cleaning method of chemical mechanical polishing retaining ring

Technical Field

The invention relates to the technical field of material cleaning, in particular to a cleaning method of a chemical mechanical polishing retaining ring.

Background

In the process of manufacturing monocrystalline silicon wafers, the monocrystalline silicon wafers are firstly thinned through chemical corrosion, the roughness is in the range of 10-20 mu m, and then coarse polishing, fine polishing and the like are carried out, so that the roughness can be controlled in the range of tens of nanometers. Generally, monocrystalline silicon wafers need to be polished more than 2 times to reach integrated circuit requirements. At present, the IC element often adopts multilayer three-dimensional wiring, that is, a plurality of metal wiring layers are sequentially arranged on a monocrystalline silicon wafer, and then corresponding etching is performed to form a wiring network. Because each layer to be etched has a very high global flatness requirement, the global flatness requirement of each layer is often ensured by polishing.

Chemical mechanical polishing (Chemical Mechanical Polishing, CMP) is a critical process in integrated circuit fabrication to achieve global uniform planarization of wafers. Unlike traditional pure mechanical or pure chemical polishing methods, the CMP technique avoids surface damage caused by pure mechanical polishing by a combination of chemical and mechanical techniques, and utilizes the principle of "soft and hard grinding" in abrasion, i.e., a softer material is used for polishing to realize high-quality surface polishing, so that the effects of chemical corrosion and mechanical grinding are balanced. The main principle of the CMP technology is that a workpiece to be polished is relatively moved with respect to a polishing pad under a certain pressure and in the presence of a polishing slurry, and a smooth surface is formed on the surface of the workpiece to be polished by means of an organic combination between the abrasive action of nanoparticles and the corrosive action of an oxidizing agent.

With the continuous progress of integrated circuit chip process technology, the demand for CMP technology is increasing. CMP technology was first used in silicon oxide polishing to perform global planarization of interlayer dielectric (ILD), and after an integrated circuit chip enters a 0.35 μm node, CMP technology is more widely used in planarization processes of tungsten metal, copper, polysilicon, etc. As the number of metal wiring layers increases, more steps are required to perform CMP polishing. Taking a 28nm node process as an example, the number of times of CMP polishing required is 12-13 times, and after entering a 10nm node, the number of times of CMP polishing is doubled to 25-26 times. The first half of the CMP polishing process in the monocrystalline silicon wafer fabrication process is statistically widely used in the following processes: rugged insulators, conductors, interlayer dielectrics (ILD), damascene metals (e.g., al, cu), shallow Trench Isolation (STI), silicon oxide, polysilicon, etc. in interconnect structures.

During polishing of wafers using CMP techniques, the wafer needs to be protected and held by a Retaining Ring (Retaining Ring). At present, in order to increase the chip yield and reduce the manufacturing cost, the diameter of a wafer is continuously increased, in addition, in order to improve the integration level of an integrated circuit, the width of a scribing line of the wafer is thinner and thinner, and the surface accuracy of the wafer is higher and higher, so that the difficulty of the CMP technology is increased. For wafers with the diameter of more than 150mm, the phenomenon of overgrinding is easy to form at the edge of the wafer, the polishing quality and the wafer utilization rate are reduced, and if a retaining ring with qualified quality is adopted, the polishing pad at the edge and the polishing pad below the wafer can be flattened to the same height. It follows that the retaining ring should have properties such as high wear resistance, corrosion resistance, low vibration characteristics, material stability and cleanliness.

While existing retaining ring materials include PPS, PC, arlonl (PTFE/PEEK), arlonEX-2618 and Arlonl287 (CF/PEEK), existing retaining ring fabrication processes include all plastic PEEK or PPS plus metal nuts, all plastic PEEK encapsulated 304 stainless steel and semi-plastic semi-metal viscose, but common retaining rings are integrally formed by bonding a machined PPS rubber ring and a machined SUS304 stainless steel with special glue. Because in the course of machining, especially in carrying out the machining process to the screw hole, can often use various engine oil etc. as the lubricant, lead to the greasy dirt that the adhesion is strong and be difficult to abluent has remained on the screw hole of retainer ring surface especially retainer ring, there is the grinding dust to fall into the screw hole bottom and not in time wash clean after the grinding of retainer ring SUS backplate moreover, the screw hole has not blasted clean screw hole after processing and has aqueous vapor and grinding powder to remain at the screw hole bottom, in addition, SUS backplate polishes and leads to polishing dust to fall into the screw hole bottom, therefore the screw hole bottom black attachment of retainer ring SUS backplate is more. As the black attachments on the thread hole bottom of the SUS backboard are strong, a common method is adopted by using a cotton stick, namely, 12 thread holes are picked and washed by adopting a non-woven cotton swab, and although structures such as thread hole chamfering, U-shaped grooves and the like can be effectively cleaned, the non-woven cotton swab is too thick to pick and wash the thread hole bottom, so that the black attachments on the thread hole bottom are too much. If the unwashed retaining ring is used directly in the CMP polishing process, the wafer will be severely contaminated, resulting in wafer scrap. Therefore, if the number of black attachments on the threaded hole bottom of the SUS back plate is large, the requirements of customers cannot be met.

In view of the foregoing, there is a need to develop an effective cleaning method for cmp retaining rings, particularly for removing black deposits from the threaded hole of SUS backing plates.

Disclosure of Invention

In view of the problems existing in the prior art, the invention provides a cleaning method of a chemical mechanical polishing retaining ring, which sequentially carries out pure water showering, cleaning and digging and washing by adopting a cleaning agent and secondary pure water showering before ultrasonic cleaning, can effectively ensure that a threaded hole positioned on an SUS surface is firstly soaked by pure water, then is flushed by adopting the cleaning agent and then is flushed by pure water for at least one time, can effectively remove black attachments at the bottom of the threaded hole, is suitable for standardized operation of batch products, and can improve the product quality and the product processing efficiency; in addition, the cleaning method adopts various types of cleaning, carries out all-round cleaning operation on the chemical mechanical polishing retaining ring, improves the cleaning quality and the cleaning effect of the chemical mechanical polishing retaining ring, and further prevents the wafer from being polluted by the chemical mechanical polishing retaining ring in the using process.

To achieve the purpose, the invention adopts the following technical scheme:

it is an object of the present invention to provide a cleaning method of a chemical mechanical polishing retainer ring, the cleaning method comprising the steps of:

(1) Respectively carrying out primary pure water flushing on a PPS surface and an SUS surface of a chemical mechanical polishing retaining ring to be cleaned, ensuring that the interior of a threaded hole positioned on the SUS surface is soaked in pure water, wiping the SUS surface by adopting a cleaning agent, carrying out digging and cleaning, respectively carrying out secondary pure water flushing on the PPS surface and the SUS surface, and ensuring that the interior of the threaded hole positioned on the SUS surface is flushed at least once;

(2) Placing the chemical mechanical polishing retaining ring obtained by cleaning in the step (1) into chemical cleaning liquid for ultrasonic cleaning, and then taking out and drying;

(3) And (3) wiping and cleaning the outer surface of the chemical mechanical polishing retaining ring obtained in the step (2), and then sequentially drying and vacuum packaging to complete the cleaning of the chemical mechanical polishing retaining ring.

According to the cleaning method, the primary pure water showering, the cleaning with the cleaning agent, the digging and washing and the secondary pure water showering are sequentially carried out before the ultrasonic cleaning, so that the threaded holes on the SUS surface are effectively guaranteed to be soaked by the pure water firstly, then the cleaning with the cleaning agent is carried out, and then the threaded holes are flushed at least once by the pure water, black attachments at the bottoms of the threaded holes can be effectively removed, the cleaning method is suitable for standardized operation of batch products, and the product quality and the product processing efficiency can be improved; in addition, the cleaning method adopts various types of cleaning, carries out all-round cleaning operation on the chemical mechanical polishing retaining ring, improves the cleaning quality and the cleaning effect of the chemical mechanical polishing retaining ring, and further prevents the wafer from being polluted by the chemical mechanical polishing retaining ring in the using process.

Because the black attachments on the thread hole bottom are mainly grinding powder, polishing dust and the like adhered by oil stains, the whole chemical mechanical polishing retaining ring cannot be cleaned by ultrasonic cleaning. In this regard, the inventor has verified through many experiments that it is required to carry out the pure water drenching in proper order before ultrasonic cleaning, wipe and draw and wash with the cleaner, the secondary pure water drenches, the pure water drenches once and is required to guarantee to be located the screw hole inside infiltration pure water of SUS face, draw and wash for the follow-up adoption cleaner and supply wet state, it can smoothly dissolve greasy dirt and break away from the screw hole inner wall to be convenient for follow-up adoption cleaner to draw and wash, after the completion to wipe and draw with the cleaner, the secondary pure water drenches can be effectively with the black attachment that breaks away from the screw hole inner wall and wash out the screw hole, especially limit and guarantee to be located the screw hole inside of SUS face is washed at least once, can realize the technological effect that the black attachment of screw hole bottom is effectively cleared away, be applicable to the standardized operation of batch product, can improve product quality and product machining efficiency.

The following technical scheme is a preferred technical scheme of the invention, but is not a limitation of the technical scheme provided by the invention, and the technical purpose and beneficial effects of the invention can be better achieved and realized through the following technical scheme.

In the step (1), the primary pure water shower and the secondary pure water shower are performed in a cleaning tank.

Preferably, in step (1), the primary pure water shower and the secondary pure water shower use ultrapure water having a resistivity of more than 18.2 Ω.

It is worth to say that the primary pure water showering and the secondary pure water showering of the invention need to strictly use ultrapure water, especially cannot use tap water for residents or even industrial water, so that white spots on the surface of the chemical mechanical polishing retaining ring after water evaporation are avoided, namely slight scale is generated after water evaporation, and the wafer is prevented from being polluted during the use of the chemical mechanical polishing retaining ring.

As a preferred technical solution of the present invention, in the step (1), the primary pure water shower includes: and (3) one circle of the PPS surface is showered, and two circles of the SUS surface are showered.

It is worth to say that the one-time pure water showering of the invention showers the SUS surface with two circles, and the water flow speed needs to be properly reduced, so as to ensure that the inside of the threaded hole positioned on the SUS surface is soaked with pure water, and the cleaning agent is adopted for subsequent cleaning and elution.

As a preferred embodiment of the present invention, in step (1), the wiping includes: and placing the chemical mechanical polishing retaining ring on a turntable in a state that the SUS surface faces upwards, and wiping the SUS surface by wiping the Kelin to be dipped in water and dipping the detergent.

It should be noted that the PPS surface of the cmp retaining ring cannot be wiped with the wiping crellin, and it is necessary to prevent the PPS surface from being scratched.

In the step (1), the preferred technical scheme of the invention includes primary cleaning, secondary cleaning and tertiary cleaning which are sequentially carried out.

Preferably, the one-time scooping includes: adopt green non-woven fabrics cotton swab to draw and wash screw hole chamfer and U type groove, because green non-woven fabrics cotton swab is thicker, can't go deep into the screw hole inside and draw and wash.

Preferably, the secondary washing includes: the cleaning liquid is dipped by a Japanese fine cotton swab to be picked up and washed at the bottom of the threaded hole and the sealing groove. In the actual operation process, a Japanese fine cotton swab can only wash the bottom of a threaded hole, and if the color of the cotton swab head of the Japanese fine cotton swab is black, the Japanese fine cotton swab needs to be immediately replaced, and the cleaning is continued until black attachments are not visible to the naked eye.

Preferably, the three-pass scooping includes: the suction nozzle hairbrush is adopted to wash the exhaust hole.

As a preferable embodiment of the present invention, in the step (2), the chemical mechanical polishing retainer ring obtained by cleaning in the step (1) is placed in an ultrasonic cleaning machine in a state where the SUS surface is facing down, and the chemical cleaning liquid is allowed to permeate at least 2cm beyond the PPS surface.

It should be noted that if the cmp retaining ring is ultrasonically cleaned with PPS facing down, the cmp retaining ring is jostled, so that it is necessary to ensure that the SUS is placed in the ultrasonic cleaner with the PPS facing down.

Preferably, in step (2), the chemical cleaning solution comprises isopropyl alcohol.

Preferably, the purity of the isopropanol is greater than or equal to 99.9wt%.

In the step (2), the ultrasonic cleaning time is 3-8min, for example, 3min, 4min, 5min, 6min, 7min or 8min, but the present invention is not limited to the above-mentioned values, and other values not shown in the above-mentioned value ranges are equally applicable.

Preferably, in the step (2), the ultrasonic electric power of the ultrasonic cleaning is 200-500W, for example, 200W, 250W, 300W, 350W, 400W, 450W or 500W, etc., but not limited to the listed values, and other non-listed values within the above-mentioned range are equally applicable.

Preferably, in the step (2), the ultrasonic working frequency of the ultrasonic cleaning is 30-100kHz, for example, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, 90kHz or 100kHz, etc., but not limited to the recited values, and other non-recited values within the above range are equally applicable.

As a preferred embodiment of the present invention, the wiping and cleaning in step (3) includes: and (3) wiping and cleaning the outer surface of the chemical mechanical polishing retaining ring obtained by drying in the step (2) by adopting dust-free cleaning cloth soaked with isopropanol.

Preferably, the wiping clean of step (3) comprises at least 3 wiping clean cycles in a clockwise direction along the outer surface of the chemical mechanical polishing retaining ring.

As a preferable technical scheme of the invention, the drying in the step (2) and the drying in the step (3) are both air drying.

Preferably, the air drying comprises: and placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun.

Preferably, the gas used for drying the gas is nitrogen or dry compressed air.

Preferably, the drying time of the air blow-drying to the bottom of the threaded hole is 10-30s, for example 10s, 15s, 20s, 25s or 30s, but not limited to the recited values, and other non-recited values in the above range are equally applicable.

The drying time of the gas blow-drying, particularly the drying time of the threaded hole of the chemical mechanical polishing retaining ring is controlled to be 10-30s, so that residues in the threaded hole with small size can be effectively removed.

As a preferable technical scheme of the invention, the cleaning method comprises the following steps:

(1) Respectively carrying out primary pure water flushing on a PPS surface and an SUS surface of a chemical mechanical polishing retaining ring to be cleaned, ensuring that pure water is soaked in a threaded hole in the SUS surface, placing the chemical mechanical polishing retaining ring on a turntable in a state that the SUS surface faces upwards, adopting a wiping and cleaning solution to be dipped in water and cleaning the SUS surface, and sequentially carrying out primary cleaning, secondary cleaning and tertiary cleaning, and respectively carrying out secondary pure water flushing on the PPS surface and the SUS surface, so as to ensure that the threaded hole in the SUS surface is flushed at least once;

wherein the primary pure water shower and the secondary pure water shower are performed in a cleaning tank; the primary pure water showering and the secondary pure water showering adopt ultrapure water with resistivity more than 18.2 omega; the primary pure water shower comprises: one circle of the PPS surface is showered, and two circles of the SUS surface are showered;

the primary cleaning comprises the following steps: adopting a green non-woven cotton swab to wash the chamfer and the U-shaped groove of the threaded hole; the secondary cleaning comprises: dipping a Japanese fine cotton swab into the detergent, and cleaning the bottom of the threaded hole and the sealing groove; the three times of digging and washing comprise: the exhaust hole is cleaned by adopting a suction nozzle brush;

(2) Placing the chemical mechanical polishing retaining ring obtained by cleaning in the step (1) in an ultrasonic cleaning machine in a state that the SUS faces downwards, enabling chemical cleaning liquid to permeate at least 2cm beyond the PPS surface, performing ultrasonic cleaning, and then taking out and drying;

wherein the chemical cleaning liquid comprises isopropyl alcohol with the purity of more than or equal to 99.9 weight percent; the ultrasonic cleaning time is 3-8min; the ultrasonic electric power of the ultrasonic cleaning is 200-500W; the ultrasonic working frequency of the ultrasonic cleaning is 30-100kHz;

the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; the drying time of the air blow-drying to the bottom of the threaded hole is 10-30s;

(3) Wiping and cleaning the outer surface of the chemical mechanical polishing retaining ring obtained by the drying in the step (2) by adopting dust-free cleaning cloth immersed with isopropanol, wherein the wiping and cleaning comprises at least 3 circles of wiping and cleaning along the outer surface of the chemical mechanical polishing retaining ring in a clockwise direction, and then sequentially drying and vacuum packaging to finish the cleaning of the chemical mechanical polishing retaining ring;

wherein the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; and the drying time of the air blow-drying to the bottom of the threaded hole is 10-30s.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) According to the cleaning method, the primary pure water showering, the cleaning with the cleaning agent, the digging and washing and the secondary pure water showering are sequentially carried out before the ultrasonic cleaning, so that the threaded holes on the SUS surface are effectively guaranteed to be soaked by the pure water firstly, then the cleaning with the cleaning agent is carried out, and then the threaded holes are flushed at least once by the pure water, black attachments at the bottoms of the threaded holes can be effectively removed, the cleaning method is suitable for standardized operation of batch products, and the product quality and the product processing efficiency can be improved;

(2) The cleaning method adopts various types of cleaning, carries out all-round cleaning operation on the chemical mechanical polishing retaining ring, improves the cleaning quality and the cleaning effect of the chemical mechanical polishing retaining ring, and further prevents the wafer from being polluted by the chemical mechanical polishing retaining ring in the using process.

Drawings

FIG. 1 is a magnified view of a screw hole microscope on the SUS surface at 40 Xmagnification before cleaning according to example 1 of the present invention;

FIG. 2 is a magnified view of a screw hole microscope on the SUS surface at 40 Xmagnification after cleaning according to example 1 of the present invention;

FIG. 3 is a magnified view of a screw hole microscope on the SUS surface at 40 Xmagnification before cleaning according to comparative example 1 of the present invention;

FIG. 4 is a magnified view of a screw hole microscope at an SUS surface at 40 times after cleaning according to comparative example 1 of the present invention;

FIG. 5 is a magnified view of a screw hole microscope at an SUS surface at 40 times before cleaning according to comparative example 2 of the present invention;

FIG. 6 is a magnified view of a screw hole microscope at the SUS surface at 40 Xmagnification after washing according to comparative example 2 of the present invention.

Detailed Description

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.

For a better illustration of the present invention, which is convenient for understanding the technical solution of the present invention, exemplary but non-limiting examples of the present invention are as follows:

example 1

The embodiment provides a cleaning method of a chemical mechanical polishing retaining ring, comprising the following steps:

wherein the chemical cleaning liquid comprises isopropyl alcohol with the purity of more than or equal to 99.9 weight percent; the ultrasonic cleaning time is 5min; the ultrasonic electric power of the ultrasonic cleaning is 400W; the ultrasonic working frequency of the ultrasonic cleaning is 60kHz;

the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; the drying time of the air blow-drying to the bottom of the threaded hole is 20s;

wherein the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; and the drying time of the air blow-drying to the bottom of the threaded hole is 20s.

For the chemical mechanical polishing retaining ring to be cleaned in this embodiment, before cleaning, a threaded hole on the SUS surface is optionally selected for observation by an artificial microscope, and an enlarged view of 40 times of the microscope is shown in fig. 1, it can be seen that black attachments are distributed at the bottom of the threaded hole, so that the threaded shape is completely covered; after the cleaning method in this example, the same screw hole on the SUS surface was observed by an artificial microscope, and the enlarged view of the microscope at 40 times is shown in fig. 2, so that the thread form can be clearly seen, and the original black attachments can be effectively removed.

Example 2

wherein the chemical cleaning liquid comprises isopropyl alcohol with the purity of more than or equal to 99.9 weight percent; the ultrasonic cleaning time is 3min; the ultrasonic electric power of the ultrasonic cleaning is 200W; the ultrasonic working frequency of the ultrasonic cleaning is 30kHz;

the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; the drying time of the air blow-drying to the bottom of the threaded hole is 10s;

wherein the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; and the drying time of the air blow-drying to the bottom of the threaded hole is 10s.

For the chemical mechanical polishing retaining ring to be cleaned in the embodiment, before cleaning, a threaded hole positioned on the SUS surface is selected for observation by an artificial microscope in a magnification of 40 times, and it can be seen that black attachments are distributed at the bottom of the threaded hole, so that the thread form is completely covered; after the cleaning method in this embodiment, the same threaded hole on the SUS surface is observed by a manual microscope with a magnification of 40 times, so that the thread form can be clearly seen, and the original black attachments are effectively removed.

Example 3

wherein the chemical cleaning liquid comprises isopropyl alcohol with the purity of more than or equal to 99.9 weight percent; the ultrasonic cleaning time is 8min; the ultrasonic electric power of the ultrasonic cleaning is 500W; the ultrasonic working frequency of the ultrasonic cleaning is 100kHz;

the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; the drying time of the air blow-drying to the bottom of the threaded hole is 30s;

wherein the drying is gas blow-drying; the gas blow-drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun; the gas adopted by the gas blow-drying is nitrogen or dry compressed air; and the drying time of the air blow-drying to the bottom of the threaded hole is 30s.

Comparative example 1

This comparative example provides a cleaning method of a chemical mechanical polishing retainer ring, which is different from example 1 in that step (1) is completely omitted and the chemical mechanical polishing retainer ring to be cleaned is directly subjected to step (2).

For the chemical mechanical polishing retaining ring to be cleaned in this comparative example, a threaded hole on the SUS surface is optionally selected for observation by a human microscope before cleaning, and the enlarged view of the microscope by 40 times is shown in FIG. 3, it can be seen that black attachments are distributed on the bottom of the threaded hole, and the thread form is completely covered; after the cleaning method described in this comparative example, the same screw hole on the SUS surface was observed by an artificial microscope, and the enlarged view of the microscope at 40 times is as shown in fig. 4, black attachments still exist, and the screw thread form was still covered.

Comparative example 2

The comparative example provides a cleaning method of a chemical mechanical polishing retainer ring, which is different from example 1 in that the primary pure water shower in step (1) is completely omitted, and the specific contents are as follows:

(1) Placing a chemical mechanical polishing retaining ring to be cleaned on a turntable in a state that an SUS surface faces upwards, wiping the SUS surface by wiping the Kelin to be dipped in water and dipping a detergent to wipe the SUS surface, sequentially carrying out primary cleaning, secondary cleaning and tertiary cleaning, respectively carrying out secondary pure water flushing on the PPS surface and the SUS surface of the chemical mechanical polishing retaining ring, and ensuring that the interior of a threaded hole positioned on the SUS surface is flushed at least once;

wherein the secondary pure water showering is performed in a cleaning tank; the secondary pure water showering adopts ultrapure water with resistivity more than 18.2 omega;

the primary cleaning comprises the following steps: adopting a green non-woven cotton swab to wash the chamfer and the U-shaped groove of the threaded hole; the secondary cleaning comprises: dipping a Japanese fine cotton swab into the detergent, and cleaning the bottom of the threaded hole and the sealing groove; the three times of digging and washing comprise: the suction nozzle hairbrush is adopted to wash the exhaust hole.

For the chemical mechanical polishing retaining ring to be cleaned in this comparative example, a threaded hole on the SUS surface is optionally selected for observation by a human microscope before cleaning, and the enlarged view of the microscope by 40 times is shown in FIG. 5, it can be seen that black attachments are distributed on the bottom of the threaded hole, and the thread form is completely covered; after the washing method described in this comparative example, the same screw hole located on the SUS surface was observed by an artificial microscope, and an enlarged view of 40 x magnification of the microscope was shown in fig. 6, and although a part of black deposit was removed, the screw thread morphology was not apparent.

The conventional cleaning method in the prior art does not set pure water shower treatment or inject pure water into each threaded hole for infiltration, so that black attachments cannot be thoroughly removed when the cleaning agent is adopted for cleaning, the black attachments and the SUS threaded hole bottoms are firmly bonded, no special mode is adopted, and the black attachments and the SUS threaded hole bottoms cannot be removed by common operation.

In contrast, the cleaning method sequentially carries out one-time pure water showering, cleaning and digging washing by adopting the cleaning agent and two-time pure water showering before ultrasonic cleaning, can effectively ensure that the threaded hole on the SUS surface is soaked by pure water, then is dug and washed, and then is flushed by pure water at least one time, can effectively remove black attachments at the bottom of the threaded hole, is suitable for standardized operation of batch products, and can improve the product quality and the product processing efficiency; in addition, the cleaning method adopts various types of cleaning, carries out all-round cleaning operation on the chemical mechanical polishing retaining ring, improves the cleaning quality and the cleaning effect of the chemical mechanical polishing retaining ring, and further prevents the wafer from being polluted by the chemical mechanical polishing retaining ring in the using process.

The detailed structural features of the present invention are described in the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope of the present invention and the scope of the disclosure.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.

In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.

Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims

1. A method of cleaning a chemical mechanical polishing retaining ring, the method comprising the steps of:

2. The cleaning method according to claim 1, wherein in step (1), the primary pure water shower and the secondary pure water shower are performed in a cleaning tank;

3. The cleaning method according to claim 1 or 2, wherein in step (1), the primary pure water shower comprises: and (3) one circle of the PPS surface is showered, and two circles of the SUS surface are showered.

4. A cleaning method according to any one of claims 1 to 3, wherein in step (1), the wiping with a cleaning agent comprises: and placing the chemical mechanical polishing retaining ring on a turntable in a state that the SUS surface faces upwards, and wiping the SUS surface by wiping the Kelin to be dipped in water and dipping the detergent.

5. The cleaning method according to any one of claims 1 to 4, wherein in the step (1), the scooping includes a primary scooping, a secondary scooping, and a tertiary scooping which are sequentially performed;

preferably, the one-time scooping includes: adopting a green non-woven cotton swab to wash the chamfer and the U-shaped groove of the threaded hole;

preferably, the secondary washing includes: dipping a Japanese fine cotton swab into the detergent, and cleaning the bottom of the threaded hole and the sealing groove;

6. The cleaning method according to any one of claims 1 to 5, wherein in the step (2), the chemical mechanical polishing retainer ring obtained by the cleaning in the step (1) is placed in an ultrasonic cleaning machine in a state where the SUS face is downward, and the chemical cleaning liquid is made to permeate at least 2cm beyond the PPS face;

preferably, in step (2), the chemical cleaning solution comprises isopropyl alcohol;

preferably, the purity of the isopropanol is greater than or equal to 99.9wt%.

7. The method according to any one of claims 1 to 6, wherein in the step (2), the ultrasonic cleaning is performed for 3 to 8 minutes;

preferably, in the step (2), the ultrasonic electric power of the ultrasonic cleaning is 200-500W;

preferably, in the step (2), the ultrasonic working frequency of the ultrasonic cleaning is 30-100kHz.

8. The cleaning method of any one of claims 1-7, wherein the wiping clean of step (3) comprises: wiping and cleaning the outer surface of the chemical mechanical polishing retaining ring obtained by drying in the step (2) by adopting dust-free cleaning cloth immersed with isopropanol;

9. The cleaning method of any one of claims 1-8, wherein the drying in step (2) and step (3) is gas blow drying;

preferably, the air drying comprises: placing the chemical mechanical polishing retaining ring on a blow-drying table, and sequentially blow-drying the PPS surface, the SUS surface and the bottom of the threaded hole by adopting a dust blowing air gun;

preferably, the gas adopted by the gas blow-drying is nitrogen or dry compressed air;

preferably, the drying time of the air blow-drying to the bottom of the threaded hole is 10-30s.

10. The cleaning method according to any one of claims 1 to 9, characterized in that the cleaning method comprises the steps of: