CN112171513A

CN112171513A - Polishing pad processing method and chemical mechanical polishing equipment

Info

Publication number: CN112171513A
Application number: CN202011057154.6A
Authority: CN
Inventors: 李武祥; 程建秀; 许玉媛
Original assignee: Nexchip Semiconductor Corp
Current assignee: Nexchip Semiconductor Corp
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2021-01-05

Abstract

The invention provides a polishing pad processing method and a chemical mechanical polishing device. The method for processing the polishing pad supplies an oxidizing agent and an acid cleaning solution to the surface of the polishing pad to be processed, the oxidizing agent is used for enabling copper and copper compounds to generate copper ions which are easy to dissolve in water and be easily removed, negative ions supplied by the acid cleaning solution enable polishing particles embedded in grooves to be wrapped and repel with the surface of the polishing pad and be easily removed, and then the polishing pad processed by the oxidizing agent and the acid cleaning solution is washed by deionized water. The method has good cleaning effect on the grinding pad, is beneficial to prolonging the service life of the grinding pad and avoids the problems of poor subsequent grinding uniformity and possible scratching of the wafer caused by poor cleaning of the grinding pad. The chemical mechanical polishing equipment is used for executing the copper metal CMP process and the polishing pad processing method, and is favorable for improving the quality and the output of the copper metal CMP process due to the good cleaning effect of the polishing pad.

Description

Polishing pad processing method and chemical mechanical polishing equipment

Technical Field

The invention relates to the technical field of semiconductors, in particular to a polishing pad processing method and chemical mechanical polishing equipment.

Background

With the development of large-scale integrated circuits, semiconductor devices are fabricated on the surface of a wafer in a high-density cluster, and the process design allows the wafer to be finely ground in some processes. Chemical Mechanical Polishing (CMP) is a commonly used Polishing process for simultaneously performing Mechanical Polishing and Chemical Polishing on a wafer. For example, in a multilevel interconnection process using copper dual damascene technology, it is necessary to form an interlayer dielectric layer on a wafer having a semiconductor device and form a hole in the interlayer dielectric layer, fill the hole with copper, and then perform a planarization process on the wafer by using a CMP process to remove excess copper outside the hole.

The existing CMP equipment includes a polishing pad (pad) disposed on a polishing platform, the surface of the polishing pad has many small protrusions, during the polishing process, a polishing solution (slurry) is supplied onto the polishing pad, the polishing solution includes a plurality of components such as polishing particles and chemical additives, after being absorbed by the polishing head, the wafer contacts with the polishing pad and is pressed on the polishing pad to move and rotate, and the polishing pad rotates in the opposite direction, so that the material on the surface of the wafer is removed under the friction action and the chemical action. In addition, the conventional CMP apparatus generally further includes a pad conditioner (pad conditioner), in which a conditioning disk (diamond disk) of the pad conditioner is capable of reciprocating on the polishing pad, the conditioning disk has diamond particles thereon, and the polishing pad is mechanically conditioned (dressing) by mechanically rubbing the conditioning disk and the polishing pad, so that the smoothed surface of the polishing pad is cut to restore the polishing capability of the polishing pad to the wafer, and meanwhile, the conditioning is performed to clean polishing by-products and polishing particles remaining in the grooves of the polishing pad.

However, the method for dressing the polishing pad by using the above polishing pad dresser has a large loss to the polishing pad, and shortens the life of the polishing pad, and for the polishing by-products and polishing particles embedded in the grooves on the surface of the polishing pad, the by-products and the polishing particles are not easily cleaned up only by using a physical dressing method, and the unclean cleaning results in unstable distribution of polishing rate, and further results in poor uniformity of the polished wafer, and the polishing particles accumulated in the grooves of the polishing pad also easily cause scratches on the surface of the wafer, thereby increasing the risk of scrapping.

Disclosure of Invention

In order to realize efficient cleaning of the polishing pad, prolong the service life of the polishing pad and improve the polishing quality, the invention provides a polishing pad processing method. In addition, a chemical mechanical polishing device is also provided.

In one aspect, the present invention provides a method for processing a polishing pad for cleaning a polishing pad used in a copper metal CMP process, the method comprising:

a first step of supplying an oxidizing agent and an acidic cleaning solution to the surface of the polishing pad, and allowing the oxidizing agent and the acidic cleaning solution to stay on the polishing pad for a period of time;

and a second step of rinsing the polishing pad with deionized water.

Optionally, a dresser is disposed above the polishing pad, and before the first step, the dresser is reciprocated on the polishing pad to polish and cut the polishing pad.

Optionally, during the cleaning process of the polishing pad, the polishing pad is rotated or vertically reciprocated.

Optionally, the rotating speed of the rotating motion is 80-150 rpm.

Optionally, the oxidant is one or a mixture of more than two of hydrogen peroxide, peracetic acid, sodium dichromate, chromic acid, nitric acid, potassium permanganate and ammonium persulfate.

Optionally, the concentration of the solution of the oxidant is 20% -40%.

Optionally, the acidic cleaning solution is one or a mixture of two or more of hydrochloric acid, dilute nitric acid, dilute sulfuric acid, acetic acid, hydrofluoric acid, sulfamic acid, citric acid and oxalic acid.

Optionally, the PH of the acidic cleaning solution is 5.8 to 7.8.

Optionally, in the first step, only dilute nitric acid is provided to the surface of the polishing pad, and the dilute nitric acid is used as the oxidizing agent and the acidic cleaning solution.

In one aspect, the present invention provides a chemical mechanical polishing apparatus for performing a copper metal CMP process and a method for processing the polishing pad, the chemical mechanical polishing apparatus having a polishing platen with a polishing pad attached thereon and a solution supply unit including a first liquid supply line, a second liquid supply line and a third liquid supply line, the first liquid supply line for supplying a polishing liquid, the second liquid supply line for supplying an oxidizing agent and the third liquid supply line for supplying an acidic cleaning liquid, all of which have liquid outlets facing the polishing pad.

The method for treating the polishing pad provided by the invention comprises the steps of providing an oxidizing agent and an acid cleaning solution on the surface of the polishing pad, wherein the oxidizing agent is used for enabling copper and copper compounds remained on the polishing pad to generate copper ions which are easy to dissolve in water, so that the copper ions are easier to remove, in addition, the acid cleaning solution is used for deeply penetrating into a groove on the surface of the polishing pad, grinding particles embedded in the groove are wrapped and repelled with the surface of the polishing pad by negative ions provided by the acid cleaning solution so as to be easy to remove, and then the polishing pad treated by the oxidizing agent and the acid cleaning solution is washed by deionized water. The method has good cleaning effect on the grinding pad, is beneficial to prolonging the service life of the grinding pad, and avoids the problems of poor subsequent grinding uniformity and possible wafer scratching caused by the cleaning failure of the grinding pad, thereby being beneficial to improving the grinding quality.

The chemical mechanical polishing equipment provided by the invention is used for executing the copper metal CMP process and the polishing pad processing method, and is favorable for improving the quality and the output of the copper metal CMP process due to the good cleaning effect of the polishing pad.

Drawings

Fig. 1 to 3 are schematic views of a CMP process for copper metal.

FIG. 4 is a side view of the new polishing pad.

Fig. 5 is a schematic view of a polishing pad to be subjected to post-polishing treatment.

FIG. 6 is a schematic diagram of a polishing pad after post-polishing treatment using a conventional process.

FIG. 7 is a schematic diagram of removing polishing particles in a trench of a polishing pad by using an embodiment of the present invention.

FIG. 8 shows the results of experiments relating to the zeta potential between the silica abrasive particles and the polishing pad and the pH of the cleaning solution.

FIG. 9 is a flow chart illustrating a method for processing a polishing pad according to an embodiment of the invention.

FIG. 10 is a graph showing the distribution of polishing rates when polishing is performed on a polishing pad treated by the method of the present invention.

Fig. 11 is a plan view of a chemical mechanical polishing apparatus according to an embodiment of the present invention.

Fig. 12 is a schematic diagram of a solution supply unit in a chemical mechanical polishing apparatus according to an embodiment of the present invention.

Description of reference numerals:

110-interlayer dielectric layer; 120-copper; 130-copper lower material; 10-a polishing pad; 20-solution supply unit.

Detailed Description

The polishing pad treating method and the chemical mechanical polishing apparatus according to the present invention will be described in detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, but merely as a convenient and clear aid in describing embodiments of the invention, which should not be construed as limited to the specific shapes of regions illustrated in the drawings. For the sake of clarity, in all the drawings for assisting the description of the embodiments of the present invention, the same components are denoted by the same reference numerals in principle, and the duplicated description thereof is omitted. The terms "first," "second," "first type," "second type," and the like in the following description are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances.

With the reduction of the feature size of semiconductor devices, copper is used to replace aluminum as the material of metal plugs disposed in dielectric layers in the subsequent processes of integrated circuits. The copper process requires a polishing process, typically a CMP process. Fig. 1 to 3 are schematic views of a CMP process for copper metal. Referring to fig. 1 to 3, as an example, in a multilevel interconnection process using a copper dual damascene technique, after forming an interlayer dielectric layer 110 on a wafer and forming a hole in the interlayer dielectric layer 110, an electroplating process is used to fill the hole with copper 120, and excess copper covers the upper surface of the interlayer dielectric layer 110 (fig. 1), a CMP process for copper may be performed in two times, wherein the first grinding (fig. 2) is mainly used to remove Bulk copper (Bulk Cu) on the interlayer dielectric layer 110, i.e., rough grinding, and the second grinding (fig. 3) has higher precision compared to the first grinding and is mainly used to remove copper closer to the surface of the interlayer dielectric layer 110 and a copper underlying material 130, and the copper underlying material 130 includes, for example, an oxide and titanium nitride.

Existing CMP equipment includes a polishing pad (pad) disposed on a polishing platen. FIG. 4 is a side view of the new polishing pad. Referring to fig. 4, a plurality of small protrusions are formed on a side of the polishing pad 10 facing a wafer in a CMP process, and during a polishing process, a polishing solution (slurry) including a plurality of components such as polishing particles and chemical assistants is supplied onto the polishing pad 10, the wafer is adsorbed by the polishing head, then contacts the polishing pad and is pressed on the polishing pad 10 to move and rotate, and the polishing pad 10 rotates in an opposite direction, so that materials on the surface of the wafer are removed by friction and chemical action. Fig. 5 is a schematic view of a polishing pad to be subjected to post-polishing treatment. Referring to fig. 5, as the polishing time and frequency increase, the polishing pad 10 has residues such as polishing by-products (indicated by triangles in fig. 5) and polishing particles (indicated by circles in fig. 5) adhered to the regions between the small protrusions (referred to as grooves in the polishing pad 10), which need to be cleaned. FIG. 6 is a schematic diagram of a polishing pad after post-polishing treatment using a conventional process. Referring to fig. 6, the current cleaning method for the polishing pad 10 mainly uses a conditioning disk to rub the polishing pad 10 for conditioning, the side of the conditioning disk contacting the polishing pad 10 is provided with diamond particles, by conditioning, the protrusions on the polishing pad 10 are cut off by a layer, and in combination with the deionized water rinsing, some residues attached to the surface of the polishing pad 10 can be removed.

However, the cutting thickness is large, which increases the deterioration speed of the polishing pad 10, and when the polishing pad 10 is worn to a certain extent, the polishing pad 10 may have poor control capability of the polishing thickness and the polishing quality may be deteriorated, and a new polishing pad may be required to be replaced, which results in high process cost. In addition, the removal effect of the residue is poor only by a physical cutting method, which affects the polishing quality of the copper metal CMP process.

In order to achieve efficient cleaning of a polishing pad, extend the usable time of the polishing pad, and improve the polishing quality, embodiments of the present invention first relate to a polishing pad processing method for processing a polishing pad used in a copper metal CMP process.

Specifically, the polishing pad processing method of the embodiment of the invention comprises the following steps: a first step of providing an oxidizing agent and an acidic cleaning solution to the surface of a polishing pad and allowing the oxidizing agent and the acidic cleaning solution to stay on the polishing pad for a period of time; and secondly, washing the grinding pad by deionized water.

In the above method, the oxidizing agent is used to react the copper remaining on the polishing pad (including in the grooves between the protrusions) with the copper compound (which is a component of the polishing by-product) to form water-soluble copper ions, which are easily washed away by the deionized water. The oxidizing agent may be selected from those known in the art that are readily available, easily recovered by disposal, and readily reacted with copper or copper compounds. The oxidant can be one or more than two of hydrogen peroxide, peracetic acid, sodium dichromate, chromic acid, nitric acid, potassium permanganate, ammonium persulfate and the like. Illustratively, the solution concentration of the oxidizing agent is about 20% to 40%, e.g., 30%. The solution of the oxidizing agent may be mixed with the acidic cleaning solution and then supplied to the surface of the polishing pad, or may be supplied to the surface of the polishing pad through different pipelines as required.

As an example, the chemical relationship of the reaction between copper attached to the polishing pad and hydrogen peroxide is as follows:

Cu+H₂O₂+2H⁺＝Cu²⁺+2H₂O

it can be seen that the dissolution of residual copper is facilitated and is more easily removed by providing an oxidizing agent on the polishing pad during post-polishing cleaning. Similarly, some copper insoluble compounds can be easily removed by reacting them with an oxidizing agent.

Some of the copper compounds or byproducts remaining on the polishing pad may react in an acidic environment to form a product that is readily soluble in water and thus easily removed from the polishing pad. As an example, copper oxide reacts with hydrogen ions (H) in an acidic environment⁺) The chemical relationship of the reaction is as follows:

2H⁺+CuO＝Cu²⁺+H₂O

the inventors have found that since the polishing slurry commonly used in copper metal CMP processes is acidic, the polishing particles on the polishing pad gradually have a positive charge during the polishing process, and correspondingly, the polishing pad gradually has a negative charge. After polishing, the portion of the polishing particles remaining on the polishing pad remains positively charged, while the polishing pad (particularly at the protrusions) remains negatively charged. FIG. 7 is a schematic diagram of removing polishing particles in a trench of a polishing pad by using an embodiment of the present invention. Referring to fig. 7, in the embodiment of the present invention, an acidic environment is formed on the surface of the polishing pad 10 by using an acidic cleaning solution, negative ions provided by the acidic cleaning solution enter the grooves of the polishing pad 10 to wrap the positively charged polishing particles embedded in the grooves, and the negatively charged wrapping objects form a repulsive force with the surface of the negatively charged polishing pad 10, so that the adhesive force is reduced, and the negatively charged wrapping objects are easily washed away by deionized water, thereby increasing the cleaning capability of the polishing pad.

The acidic cleaning solution used in the first step may be selected according to the cleaning effect of the polishing pad. For example, in one embodiment, the acidic cleaning solution may be one or a mixture of two or more selected from hydrochloric acid, dilute nitric acid, dilute sulfuric acid, acetic acid, hydrofluoric acid, sulfamic acid, citric acid, and oxalic acid. In one embodiment, the acidic cleaning solution may be a small-molecule organic acid. In general, the present solution utilizes negative ions in an acidic cleaning solution to facilitate removal of positively charged abrasive particles on the polishing pad, and in order to coat the positively charged abrasive particles attached to the depth of the grooves with negative charges for easy removal, the acidic cleaning solution preferably employs an acidic solution with a relatively small solute molecular weight in order to facilitate the negative ions to enter between the small protrusions (i.e., inside the grooves) on the surface of the polishing pad. It should be noted that, although some acidic liquid and some oxidizing agent are added to the polishing slurry used in the copper metal CMP process in some application scenarios, the acidic liquid and the oxidizing agent in the polishing slurry cannot achieve the effect of the oxidizing agent and the acidic cleaning solution added to the polishing pad in the first step, because the polishing slurry is continuously discharged along with the progress of the polishing process.

Preferably, the present invention selects to use dilute nitric acid which is small molecule and has strong oxidizing property to perform the first step, i.e. before the second step of washing, only dilute nitric acid is provided to the surface of the polishing pad, and the polishing pad is cleaned by using the dilute nitric acid as the oxidizing agent and the acidic cleaning solution. The dilute nitric acid has strong water solubility, is easy to permeate into the grooves with small gaps on the grinding pad, and can react Cu and byproducts to generate Cu which is easy to dissolve in water²⁺And is easier to remove under the washing of deionized water. In addition, in the mixing process of some oxidants (such as hydrogen peroxide) and acidic solution, the decomposition is accelerated to generate water without oxidability, the stability control of the cleaning capability is not good, and the problem can be avoided by adopting single dilute nitric acid to provide oxidability and acidity.

It was found that the residual abrasive particles on the polishing pad had different Zeta potentials (Zeta potentials) from the polishing pad under different pH conditions, and thus different aggregation states. Taking the main component of the abrasive particles, silica, for example, the relationship between the state and the zeta potential is shown in the following table.

Watch 1

Zeta potential	State of silica
		0mV～-5mV	Producing colloids and causing coagulation or aggregation
-10mV～-30mV	Unstable state
		-30mV～-40mV	General stability
-40mV～-60mV	Better stability

FIG. 8 shows the results of experiments relating to the zeta potential between the silica abrasive particles and the polishing pad and the pH of the cleaning solution. Referring to fig. 8, when the PH of the acid cleaning solution is in the range of 5.8 to 7.8, the polishing particles can be controlled to be in a stable state, so as to prevent the polishing particles from generating colloid to be condensed and adhered to the surface of the polishing pad, thereby being easier to remove from the polishing pad. Therefore, in the polishing pad treatment method of the present embodiment, the PH of the acidic cleaning solution in the first step is preferably 5.8 to 7.8.

FIG. 9 is a flow chart illustrating a method for processing a polishing pad according to an embodiment of the invention. Referring to fig. 9, in some embodiments, a dresser used in an existing CMP process may be used, and before the first step in the polishing pad processing method of the present disclosure, the dresser may be used to perform a reciprocating motion on the polishing pad 10 to polish and cut the polishing pad 10, so as to quickly recover the polishing capability. Moreover, because the first step provides the oxidizing agent and the acidic cleaning solution onto the polishing pad and the polishing pad is kept for a period of time (e.g., about 5s to 10s) for chemical cleaning, so that the oxidizing agent and the acidic cleaning solution chemically react with the residues on the surface of the polishing pad to generate ions easy to remove and negatively charged inclusions, and the second step washes the polishing pad with deionized water, the removal effect of the residues on the polishing pad can be greatly improved, so that compared with the prior art, the intensity of physical dressing of the polishing pad by using the dresser in the embodiment of the present invention can be reduced, or in the same polishing pad treatment process, the thickness of the polishing pad cut by using the dresser can be reduced compared with the technical scheme, and the same or better cleaning effect can still be achieved. Therefore, the scheme of the embodiment of the invention is beneficial to prolonging the service life of the single polishing pad, namely prolonging the service life of the single polishing pad, and the consumption of the polishing pad can be reduced, thereby being beneficial to reducing the process cost.

In the first step, the oxidizing agent and the acidic cleaning solution may be provided on the polishing pad 10 by dripping, spraying, sprinkling, etc., and distributed uniformly on each area of the polishing pad 10 to be cleaned as much as possible, and before performing the second step of deionized water rinsing, the oxidizing agent and the acidic cleaning solution are allowed to stay on the polishing pad 10 for a period of time, for example, 5s to 10s, so that the oxidizing agent and the acidic cleaning solution are sufficiently spread and penetrated into the polishing pad 10, the oxidizing agent is sufficiently chemically reacted, and the negative charges in the acidic cleaning solution may penetrate into the grooves of the polishing pad to wrap the positively charged polishing particles or other substances, thereby being easily removed. In addition, some organic matters on the grinding pad can be ionized and salinized under an acidic environment, so that the organic matters are dissolved in water and are convenient to remove. Alternatively, in order to accelerate the penetration, reaction and mixing of the oxidizing agent and the acidic cleaning solution in the polishing pad 10, the polishing pad 10 may be rotated during the whole cleaning process or during a part of the cleaning process, and the rotation speed of the rotation may be set to 80-150 rpm. Alternatively, the polishing pad 10 may be reciprocated up and down by controlling the work table under the polishing pad 10, for example, as micro-vibration, so that the polishing pad 10 reciprocates vertically with the work table, for example, the amplitude of the vertical reciprocation may be less than 1 cm. The rotation motion and the vertical reciprocation motion may be alternately performed.

In some embodiments of the present invention, after performing the first step, the method for treating a polishing pad may further include providing an appropriate amount of surfactant to the polishing pad for removing some organic impurities from the polishing pad 10. The surfactant may be one selected from the group consisting of a hydroxy acid salt, a sulfuric acid ester salt, a sulfonic acid salt, an amine salt, and a phosphoric acid ester salt. In some embodiments, the surfactant may also be mixed with an oxidizing agent or an acidic cleaning solution prior to addition to the polishing pad.

Referring to fig. 9, after the oxidizing agent and the acidic cleaning solution are sufficiently reacted and mixed with the residue on the polishing pad, the second step of the embodiment of the invention is to rinse the polishing pad 10 with deionized water, so that the copper ions, polishing particles and other residues on the polishing pad 10 are washed away. The deionized water may be ultrapure water to avoid introducing impurities, and in addition, when the polishing pad 10 is rinsed, high-pressure deionized water is preferably sprayed onto the surface of the polishing pad to rinse, so as to improve the removal effect and restore the polishing pad 10 to be electrically neutral. The time for rinsing with deionized water is about 4 s-6 s. After the second step, the polishing pad 10 may be further wetted with deionized ultrapure water to ensure that the polishing pad 10 is wet, which may reduce the risk of being scratched relative to a dry state.

In the method for processing a polishing pad described in the embodiments of the present invention, when a polishing pad used in a copper metal CMP process is processed, an oxidizing agent and an acidic cleaning solution are provided to a surface of the polishing pad, and the oxidizing agent is used to generate copper ions that are easily soluble in water from copper and copper compounds remaining on the polishing pad, so that the copper ions are easily removed. The method has good cleaning effect on the grinding pad, is beneficial to prolonging the service life of the grinding pad, and avoids the problems of poor subsequent grinding uniformity and possible wafer scratching caused by the cleaning failure of the grinding pad, thereby being beneficial to improving the grinding quality. FIG. 10 is a graph showing the distribution of polishing rates when polishing is performed on a polishing pad treated by the method of the present invention. Referring to fig. 10, wherein the abscissa is the distance (in mm) between each position on the wafer surface and the center of the wafer, and the ordinate corresponds to the polishing rate at each position, cycles 1 through 6 refer to the number of times the wafer reciprocates on the polishing pad. As can be seen from fig. 10, when the polishing pad treated by the above-mentioned polishing pad treatment method is used for performing the copper metal CMP process, the polishing rate difference between different positions from the center of the polishing pad is small, and the polishing rate is stable, which indicates that the residue on the polishing pad is substantially removed and the cleaning effect is good.

Embodiments of the present invention further relate to a chemical mechanical polishing apparatus for performing a copper metal CMP process and a polishing pad treatment method thereof, the chemical mechanical polishing apparatus having a polishing platen to which a polishing pad 10 (see fig. 4 to 7) is attached and a solution supply unit 20 (see fig. 12) including a first liquid supply line, a second liquid supply line, and a third liquid supply line, each of which has a liquid outlet facing the polishing pad 10, the first liquid supply line being configured to supply a polishing liquid, the second liquid supply line being configured to supply an oxidizing agent, and the third liquid supply line being configured to supply an acidic cleaning liquid.

Fig. 11 is a plan view of a chemical mechanical polishing apparatus according to an embodiment of the present invention. Referring to fig. 11, in one embodiment, the chemical mechanical polishing apparatus includes four polishing stations a-D, wherein the polishing stations a and C are used for polishing and removing bulk copper on the wafer, and the polishing stations B and D are used for further fine polishing the wafer polished by the polishing stations a and C, respectively, to remove copper closer to the surface of the interlayer dielectric layer 110 and copper underneath materials (such as silicon oxide and titanium nitride). After polishing, the polished wafer may be subjected to a cleaning process and a drying process by a cleaning apparatus (not shown).

Fig. 12 is a schematic diagram of a solution supply unit in a chemical mechanical polishing apparatus according to an embodiment of the present invention. Referring to fig. 12, in the chemical mechanical polishing apparatus according to the embodiment of the invention, the solution supply unit 20 can supply a polishing solution onto the polishing pad 10 during the CMP process by using the first liquid supply line i to perform a copper metal CMP process, and can supply an oxidizing agent (in a liquid manner) through the second liquid supply line ii according to the cleaning requirement of the polishing pad 10 after polishing is finished, and supply an acidic cleaning solution through the third liquid supply line iii, as described in the method for processing the polishing pad according to the embodiment of the invention, the oxidizing agent can make the copper and the copper compound remaining on the polishing pad generate copper ions that are easily dissolved in water and are more easily removed, while the acidic cleaning solution penetrates into the grooves on the surface of the polishing pad 10, and the polishing particles embedded in the grooves are wrapped and repelled from the positively charged surface of the polishing pad by using negative ions provided by the acidic cleaning solution and are easily removed (flowed away or removed by rinsing with subsequent deionized water), so that the removal effect of the residue adhered to the polishing pad 10 can be improved. In one embodiment, the chemical mechanical polishing apparatus may further include a deionized water supply unit (not shown), which sprays high-pressure deionized water to the polishing pad 10 to be cleaned through a corresponding pipeline, cleans the polishing pad by using a physical external force, and carries residues with poor adhesion away from the polishing pad.

The above description is only for the purpose of describing the preferred embodiments of the present invention and is not intended to limit the scope of the claims of the present invention, and any person skilled in the art can make possible the variations and modifications of the technical solutions of the present invention using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention, and therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention belong to the protection scope of the technical solutions of the present invention.

Claims

1. A method for processing a polishing pad, which is used for cleaning the polishing pad used in a copper metal CMP process, is characterized in that the method for processing the polishing pad comprises the following steps:

and a second step of rinsing the polishing pad with deionized water.

2. A method for treating a polishing pad as recited in claim 1, wherein a dresser is provided above the polishing pad, and the dresser is reciprocated on the polishing pad before the first step to perform dressing cutting on the polishing pad.

3. The method of claim 1, wherein the polishing pad is rotated or vertically reciprocated during the cleaning of the polishing pad.

4. The method of claim 3, wherein the rotational speed of the rotational motion is 80 to 150 rpm.

5. The method for treating a polishing pad according to claim 1, wherein the oxidizing agent is one or a mixture of two or more selected from hydrogen peroxide, peracetic acid, sodium dichromate, chromic acid, nitric acid, potassium permanganate, and ammonium persulfate.

6. The method of claim 5, wherein the solution concentration of the oxidizer is 20% to 40%.

7. The method of claim 1, wherein the acidic cleaning solution is one or a mixture of two or more selected from the group consisting of hydrochloric acid, dilute nitric acid, dilute sulfuric acid, acetic acid, hydrofluoric acid, sulfamic acid, citric acid, and oxalic acid.

8. The method of claim 1, wherein the acidic cleaning solution has a pH of 5.8 to 7.8.

9. The method of claim 1, wherein in the first step, dilute nitric acid is provided only to the surface of the polishing pad, and the dilute nitric acid is used as the oxidizing agent and the acidic cleaning solution.

10. A chemical mechanical polishing apparatus for performing a copper metal CMP process and the polishing pad treatment method of any one of claims 1 to 9, the chemical mechanical polishing apparatus having a polishing platen with a polishing pad attached thereon and a solution supply unit including a first liquid supply line, a second liquid supply line, and a third liquid supply line, the first liquid supply line for supplying a polishing liquid, the second liquid supply line for supplying an oxidizing agent, and the third liquid supply line for supplying an acidic cleaning liquid, all of which have liquid outlets directed toward the polishing pad.