WO2013125807A1

WO2013125807A1 - Polishing pad and method for manufacturing same

Info

Publication number: WO2013125807A1
Application number: PCT/KR2013/001083
Authority: WO
Inventors: 안봉수; 장영준; 이상목; 정휘국; 송기천; 김승근; 서장원; 추정선
Original assignee: 케이피엑스케미칼주식회사; 삼성전자주식회사
Priority date: 2012-02-20
Filing date: 2013-02-12
Publication date: 2013-08-29
Also published as: US20130212951A1; US20140364044A1; CN103252729A; TW201338923A; KR20130095430A; JP5588528B2; JP2013169645A

Abstract

The method for manufacturing a polishing pad according to the present invention includes the steps of: mixing materials for forming a polishing layer; forming at least two types of pores by mixing the mixture of the above step with at least two of an inert gas, a capsule type foaming agent, a chemical foaming agent, and a liquid state differential element, each of which has a controllable pore size; manufacturing a polishing layer which includes at least two types of pores by gelating or hardening the mixture which is produced through the above steps; and a step of processing the polishing layer so as to distribute the pores of at least two types on the surface by opening up the pores.

Description

[Specifications

[Name of invention]

Polishing pad and manufacturing method thereof

Technical Field

The present invention relates to a polishing pad and a method for manufacturing the same, and more particularly, to a polishing pad and a method for manufacturing the same, which enables efficient slurry collection and transportation.

Background Art

Chemical Mechanical Flattening / Polishing

PLANARIZATION / CHEMICAL MECHANICAL POLISHING (hereinafter referred to as CMP) is a process introduced for the global planarization of semiconductor devices, and is further increased as the wafers have large diameters, high integrations, line widths, and wiring structures. It is becoming.

Polishing speed and flatness are important in the CMP process, which are determined by the process conditions of the polishing equipment and the polishing slurry and polishing pads, which are the consumable members used. In particular, the polishing pad uniformly distributes the supplied polishing slurry on the wafer while in contact with the surface of the wafer, and causes physical removal by the abrasive particles inside the polishing slurry and the surface protrusions of the polishing pad.

At this time, the surface of the polishing pad in direct contact with the wafer should keep the polishing slurry saturated, so that the flow of the polishing slurry may be / sourced. To this end, techniques are disclosed in US Pat. Nos. 5,578,362 and the like that allow the formation of fine holes (eg pores) in the polishing pad surface.

In order to enhance the role and performance of the polishing pad in the CMP process, it is very important to maintain the saturated slurry in the polishing pad, thus forming various grooves (GROOVE) to form a large slurry flow on the polishing pad. In addition, as described above, micropores are formed on the surface of the polishing pad by opening of a microporous material.

However, the technology has been developed in the form of attempting a variety of patterns in relation to the formation of the groove, the porous pore technology for the formation of micropores is limited to the use of a specific pore forming method. That is, the conventional. There are some advantages and disadvantages, depending on the method, and the advantages and disadvantages. In actual CMP processes, the process is adjusted to take advantage of these advantages and disadvantages. However, as the demand for more detail and sophistication in semiconductor processing

The CMP process also has a growing need for technology to produce porous pores that has evolved one step further to support this.

[Detailed Description of the Invention]

The present invention has been made in view of the above-mentioned conventional request, and an object thereof is to provide a polishing pad and a method of manufacturing the same, which can maximize polishing performance and planarization performance by collecting and using the polishing slurry during the CMP process. .

In order to achieve the above object, a polishing pad performing a polishing process by contacting and moving with a surface of an object to be polished according to the present invention, wherein the polishing pad includes a polishing layer, and the polishing layer comprises an inert gas, It consists of at least two porous pores each having pore size control by at least two of the encapsulated foaming agent, the chemical blowing agent and the liquid microelement, the pores by opening the two or more porous pores on the surface of the polishing layer It is characterized in that the distribution.

In addition, to achieve the above object, a method of manufacturing a polishing pad according to the present invention comprises the steps of mixing a polishing layer forming material; Mixing at least two types of inert gas, a capsul-type blowing agent, a chemical blowing agent, and a liquid microelement vapor, each of which is capable of pore size control, to form two or more kinds of porous pores; Gelling and curing the mixture produced through the above steps to produce an abrasive layer comprising the two or more porous pores; Processing the abrasive layer to distribute the pores by opening the two or more multi-pore pores on the surface.

[Brief Description of Drawings]

1 is a cross-sectional view of a polishing pad according to an embodiment of the present invention, FIG. 2 is an enlarged image of a cross section of the polishing pad polishing layer of FIG. 1,

3 is a schematic diagram of a polishing apparatus equipped with the polishing mill of FIG. 1,

Figure 4 is a flow chart of the polishing layer manufacturing process of the polishing pad according to an embodiment of the present invention,

5 and 6 are surface pore images of the polishing layer including the pore by the inert gas and the pore by the liquid microelement according to an embodiment of the present invention, _ .7 is the name H method (Example 2 and Example 3) The figure shows the comparison of the polishing efficiency of the mold pad of the stand-up pad with the conventional method. EXAMPLE

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a polishing pad according to an embodiment of the present invention.

As shown in the figure, the polishing pad 100 according to the embodiment of the present invention is composed of a support layer 110 and the polishing layer 120. As shown in FIG. 3, the support layer 110 is a portion that allows the polishing pad 100 to adhere to the pann 3. The support layer 110 is made of a material having a resilience against the force of pressing the silicon wafer 7, which is the target to be polished, which is loaded on the head 5 opposite to the pann 3. 120 serves to support the silicon wafer 7 with a uniform elastic force. Therefore, mainly made of a non-porous solid homogeneous elastomer material, the hardness is lower than the abrasive layer 120 formed thereon.

In addition, at least a portion of the support layer 110 may be transparent or translucent to allow transmission of the light beam 170 used to detect flatness of the surface to be polished. In FIG. 3, the wafer 7 on which a to-be-polished film such as a metal or an insulating layer is formed is illustrated as the object to be polished. Of course, it can be used as a polishing target. In some cases, the polishing pad 100 may be configured without the support layer 110. In addition, FIG. 3 illustrates a case in which the shape of the polishing pad 100 is circular so as to be suitable for the rotary polishing apparatus 1, but may be modified in various shapes of rectangular and square round shapes according to the shape of the polishing apparatus 1. Of course.

As shown in FIG. 3, the polishing layer 120 is a portion in direct contact with the wafer 7 to be polished. The polishing layer 120 may be formed by mixing or chemically bonding a predetermined polishing layer forming material. That is, the polymer matrix 130 forming the polishing layer 120 is made of various known components, and descriptions of known materials and forming materials will be omitted.

The abrasive layer 120 may include two or more kinds of porous pores, each of which is formed by at least two inert gases, a capsular blowing agent, a chemical foaming agent, and a liquid microelement vapor. This corresponds to what has been done.

That is, the types of porous pores can be distinguished from each other by the method of forming the porous pores, which are formed by the inert gas. Pore produced by blowing agent, produced by liquid microelement At least two kinds of pores are included in the polishing layer 120 according to the present invention.

Here, each kind of pores may be formed to distinguish the size from each other, but the present invention is not limited thereto.

Hereinafter, as an example of the present invention, it is assumed that two kinds of porous pores, namely, a first porous pore and a second porous pore, are formed in the polishing layer 120, and in particular, the first porous pore is formed by a liquid microelement. And the second porous pore is formed by inert gas.

As such, when the first porous pore by the liquid microelement is included in the polishing layer, the material produced by the mixing mixture of the above-described polishing layer forming material is, for example, a hydrophilic polymer matrix containing polyalkylene glycol (hereinafter ' Polyalkylene glycol-containing hydrophilic polymer matrix.

That is, the polishing layer occupies a certain area in the polyalkylene glycol-containing hydrophilic polymer matrix 130 and is uniformly distributed, that is, embedded liquid microelements (hereinafter referred to as 'embedded liquid microelements'). A second porous pore 142, which is a vapor phase pore including the first porous pore 141 and an embedded inert gas, may be included.

The actual examples of the first porous pore (liquid microelement pore) 141 and the second porous pore (gas phase pore) 142 included in the polishing layer are as shown in FIG. 2. The abrasive layer surface 160 in direct contact with the wafer 7 has a plurality of micropores 141 ', 142' defined and opened by a first porous pore 141 and a second porous pore 142. These are arranged uniformly.

Here, the meaning that the pores 141 'and 142' are defined and opened by the respective porous pores 141 and 142 means that the liquid microelement or the inert gas embedded in the polishing layer 120 leaks to the outside. This means that the region containing the microelement or the inert gas remains as the pores 141 ′ to capture certain substances from the outside.

As the polishing pad 100 wears during the polishing process, the embedded porous pores 141 and 142 are continuously exposed to the polishing layer surface 160 to form pores 141 'and 142', which is a polishing slurry ( 13). Therefore, ¹ t of poly ³ L mats are present on the polishing surface (160), so that the silicon wafer (7) to be polished is not polished. It can grind uniformly. The polyalkylene glycol-containing hydrophilic polymer matrix 130 is preferably formed of a material that is insoluble in the polishing slurry _13, which is a chemical solution for planarization. For example, as shown in FIG. 3, the polishing slurry 13 supplied through the nozzle 11 of the polishing equipment 1 is formed of a material that cannot penetrate.

The polyalkylene glycol-containing hydrophilic polymer matrix 130 may be formed by chemical bonding or physical mixing between the polymer matrix forming material, the hydrophilic material, and the polyalkylene glycol compound.

Here, the material of the polymer matrix produced by the material for forming the polymer matrix is polyurethane, polyether, polyester, polysulfone, polyacryl, polycarbonate, polyethylene, polymethyl methacrylate, polyvinyl acetate, polyvinyl chloride, polyethylene It may correspond to any one selected from the group consisting of imines, polyether sulfones, polyether imides, poly ketones, melamines, nylons and hydrocarbon fluorides or mixtures thereof.

The polyalkylene glycol-containing hydrophilic polymer matrix 130 corresponds to a combination of a hydrophilic material and a polyalkylene glycol compound by a chemical method or a physical method in the polymer matrix.

Hydrophilic substances include polyethylene glycol, polyethylene propylene glycol, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ether, polyethylene glycol fatty acid ester, polyoxyethylene alkyl amine ether, glycerin fatty acid ester, sugar fatty acid ester, sorbitol fatty acid. One example is any one selected from the group consisting of esters or mixtures thereof.

The polyalkylene glycol compound may be any one or a mixture thereof selected from the group consisting of compounds in which an alkylene oxide is added to a compound containing water or active hydrogen.

The material for forming the abrasive layer as described above may be configured to include various materials in addition to the description.

The embedded liquid microelement forming the first porous pore 141 is formed of a liquid material which is incompatible with the polyalkylene glycol-containing hydrophilic polymer matrix 130, and includes an aliphatic mineral oil, an aromatic mineral oil, and a silicon having no hydroxyl group at the end of the molecule. Any ^one selected from the group consisting of oil, soybean oil, palm oil, palm oil, cottonseed oil, camellia oil, and hardened oil may be mixed.

The first porous pore 141 by the embedded liquid microelement has a fine spherical shape. And is preferably dispersed and formed in the polyalkylene glycol-containing hydrophilic polymer matrix 130. It is preferable that the average diameter of a spherical shape is 1-, and it is more preferable that it is 2-10 IM. When the diameter of the sphere is in the above range, it is most suitable for the collection and supply of the abrasive slurry 13. However, the suitable spherical diameter may vary depending on the type of abrasive slurry 13 used, and the embedded liquid microelement

The size of 141 can also vary accordingly.

The shape of the first porous pore 141, i.e., the spherical mean diameter and concentration, by the embedded liquid microelement can be easily and variously controlled by changing the degree of hydrophilicity of the polyalkylene glycol-containing hydrophilic polymer matrix 130. have.

In addition, the shape of the first porous pore 141 by the embedded liquid microelement is easily and variously controlled by the increase ratio of the liquid material. Preferably, the polymer matrix forming material, such as 20 to 50% by weight, more preferably 30 to 40% by weight, based on the total amount of the polyurethane substrate, is mixed with the liquid material in a desired form. One porous pore 141 may be produced.

The size and concentration of the first porous pore 141 and the pores 141 'defined by the embedded liquid microelements may be determined by the degree of hydrophilicity and / or liquidity of the polyalkylene glycol-containing hydrophilic polymer matrix 130. Since the amount can be adjusted in various ways, there is an advantage that the production of the polishing pad 100 having various polishing performances is possible depending on the type of the polishing target and / or the type of the polishing slurry 13.

On the other hand, the second porous pore 142 is formed by injection of an inert gas, a capsul-type blowing agent, a chemical foaming agent and the like.

Here, the inert gas may be a chemically stable gas having a valence of '0', such as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), etc. It is contained in such an inert gas. Furthermore, the inert gas corresponds to any gas other than the Group 8 element of the periodic table that does not react with the polymer matrix, such as N ₂ , for example, but does not participate in urethane reaction.

In addition, the foaming agent is mixed with a predetermined raw material to generate a large amount of bubbles by vaporization or reaction by heat, and can be largely classified into a chemical foaming agent and a physical foaming agent.

Chemical blowing agent is the isocyanate group (基) activated by pressing the water because of foaming and ⁷ i in the carbon dioxide produced by banung the like water agent to the S ^. I JI, physical trace blowing agent is mixed into the gas or decomposable or Using evaporative blowing agent It does not participate in the polymer reaction because it forms bubbles. Types and features of these blowing agents are only known in the art, and thus will not be described in more detail.

The low 12 porous pore 142 is formed in the abrasive layer by mixing an inert gas or various blowing agents (capsular or chemical blowing agents), and may have a larger radius than the first porous pore 141, and preferably The second porous pore 142 is formed to have a volume 10 times or more than the first porous pore (141).

Hereinafter, a process of manufacturing a polishing layer 120 of the polishing pad 100 according to an embodiment of the present invention will be described with reference to FIG. 4.

First, materials for forming the polishing layer 120 are mixed (S100). Specifically, the materials for forming the polyalkylene glycol-containing hydrophilic polymer matrix 130 may be mixed with each other (step S100).

Here, the material for forming the polyalkylene glycol-containing hydrophilic polymer matrix 130 is a material produced by the mixing or reaction of a hydrophilic material and a polyalkylene glycol compound to the material for forming the polymer matrix. It is preferable to advance this by a stirring method.

In the mixing process, liquid substances such as mineral drifting are mixed together, which can be mixed by administering with an inert gas such as argon (or a specific blowing agent to replace it).

The amount of the liquid substance and the inert gas to be mixed here can be adjusted as much as the pore size for each type to be produced.

Subsequently, gelation and curing reaction are performed (S110). That is, the mixture is injected into a mold of a predetermined shape and solidified through gelation and curing. In this case, the gelation reaction may be performed at 80 to 90 degrees for 5 to 30 minutes, and the curing reaction may be performed at 80 to 120 degrees for 20 to 24 hours, but the specific process temperature and time may be variously changed to find the optimum conditions. Of course it can.

Finally, the resultant cured to a predetermined shape is processed (S120). Processing includes demolding, cutting, surface finishing and cleaning. First, the cured semi-coal water is taken out of the mold and cut to have a predetermined thickness, shape, and shape. In order to improve productivity, the fine abrasive layer 120 may be formed into a sheet by the method of ¾_ known in the art for the manufacture of polymer sheets such as casting and extrusion molding. All. On the surface of the polishing layer 120, the polishing slurry 13 is a working surface of the polishing layer 120. It is desirable to form various types of grooves that can be supplied evenly to the.

Thereafter, the polishing layer 120 is completed through a washing process. During the cleaning process, the liquid microelements 141 of the polishing layer surface 160 are eluted to distribute pores 141 ′ open to the polishing layer surface 160. At this time, it is preferable to proceed with the cleaning process using a cleaning liquid such that the eluted liquid microelement 141 does not remain on the polishing layer surface 160.

The polishing pad 100 may be completed using only the polishing layer 120, but if necessary, the support layer 110 may be manufactured by a method well known in the manufacturing process of the polishing pad 100, and the support layer 110 and the polishing layer ( 120 may be combined to complete polishing pad 100.

More detailed information on the present invention will be described through a comparison of the following specific experimental examples, and details not described herein will be omitted since those skilled in the art can sufficiently infer technically. Of course, the scope of the present invention is not limited by the following experimental examples.

Experimental Example 1

50 kg polytetramethylene glycol (molecular weight 1000), 50 kg polyethylene glycol (molecular weight 1000) and 52 kg of toluene diisocyanate were added to a 200 kg reaction machine, and the reaction was carried out for 4 to 5 hours at a silver temperature of 70 to 80 ° C. The content was 11.0%. The viscosity of the isocyanate prepolymer thus prepared was 6,900 cPs (25 ° C).

Experimental Example 2

100 kg of isocyanate prepolymer of Experimental Example 1, 46 kg of mineral oil (hereinafter referred to as KF-70) (manufactured by Seojin Chemical), and 33 kg of MOCA were discharged through a mixing head of 5000 rpm using a casting machine. At this time, Ar gas, an inert gas, is administered to the mixing head in a 10% volume ratio.

The mixture is then immediately poured into a square mold. The injected reaction solution is gelled for 30 minutes and then cured for 20 hours in a 100 ^° C oven.

The prepared cured product was taken out of the mold and the surface was cut to prepare a polishing layer of the polishing pad.

A side of polishing to be run; The Por_e image ¾ is also shown. -Polishing performance and planarization performance of the manufactured pad is shown in Figure 7 (polishing pad according to the present embodiment) The nap is shown in "Hybridpoe").

100 kg of isocyanate prepolymer of Experimental Example 1, 46 kg of mineral oil (hereinafter referred to as KF-70) (manufactured by Seojin Chemical), and 33 kg of MOCA were discharged through a mixing head of 5000 rpm using a casting machine. At this time, the inert gas Ar gas is administered to the mixing head at a volume ratio of 20%.

The mixture is then immediately poured into a square mold. The injected reaction solution is gelled for 30 minutes and then cured for 20 hours at 100 ^° C. Aubon.

The surface pore image of this polishing layer is shown in FIG. 6.

Polishing performance and planarization performance of the prepared pad are shown in FIG. 7 (a polishing pad according to the present embodiment is known as “hybrid pore 2”). In the drawings, the "solid capsular pore" shows the case of a polishing pad using only a single solid capsular pore rather than using different kinds of composite pores (i.e., a giant U porous pore and a low 12 porous pore) as in the present invention. (Wherein the solid capsule may mean a fine powder with an empty interior), the “liquid microelement pore” also has different types of composite pores (ie, the first porous pore and the second porous pore) as in the present invention. It does not use, but shows a case of a polishing pad including only a single liquid microelement. In the case of using composite pores having different sizes as described above, the relatively small first porous pore collects a small amount of abrasive slurry particles to enable precise polishing, and the second large porous pore is relatively large at once. By collecting large amounts of abrasive slurry particles, high polishing rates can be achieved.

As such different types of pores are simultaneously included in the polishing layer of the polishing pad, more precise polishing can be performed.

In the above-described embodiment, two types of porous pores have been described mainly for forming, but the present invention is not limited thereto. As described above. That is, the polishing pad according to the present invention includes three or more types of pores formed by liquid microelements, pores formed by solid capsules, pores formed by injection of inert gas, and pores formed by chemical blowing agents. ^ Sizes of porous pore types generated at this time may be as described above. Of course, it may be changed depending on the type of the material for forming the pore or to increase the polishing efficiency.

In particular, although each pore forming method can control the pore size by the concentration of the mixed material and the reaction silver, the pore of each type does not have to have a different size.

On the other hand, the present invention is not limited to the above specific embodiments, but can be modified and modified in various ways without departing from the spirit of the present invention.

【Industrial Availability】

As described above, according to the present invention, it is possible to implement more efficient CMP polishing performance by enabling efficient slurry capture and transfer by controlling multiple (two dipole) pores instead of a single pore. This makes it possible to achieve the sophistication of the CMP process required by the miniaturization of the semiconductor process.

Claims

[Claims]

[Claim 1]

(a) mixing the abrasive layer forming material;

(b) mixing at least two of an inert gas, a capsular blowing agent, a chemical blowing agent, and a liquid microelement capable of controlling pore size in the mixture of step (a), respectively, to form two or more kinds of porous pores;

(c) gelling and curing the mixture produced through step (b) to produce an abrasive layer comprising the two or more porous pores;

(d) processing the polishing layer to distribute the pores by opening the two or more types of porous pores on the surface.

[Claim 2]

The method of claim 1, wherein the inert gas is selected from a group 8 element of the periodic table and a gas that does not react with the polishing layer forming material.

[Claim 3]

The liquid material of claim 1, wherein the liquid substance constituting the liquid microelement is any one selected from the group consisting of aliphatic mineral oil, aromatic mineral oil, silicone oil having no hydroxyl group at the end of the molecule, soybean oil, palm oil, palm oil, cottonseed oil, camellia oil, and hydrogenated oil. A method for producing a polishing pad, characterized in that a mixture thereof.

[Claim 4]

A polishing pad for performing a polishing process by moving in contact with a surface to be polished,

The polishing pad includes a polishing layer,

The abrasive layer comprises two or more porous pores each having a pore size control by at least two of an inert gas, an encapsulating foaming agent, a chemical blowing agent and a liquid microelement,

Polishing pads, characterized in that the pores are distributed by the opening of the two or more porous pores on the surface of the polishing layer.

[Claim 5]

The can 4 ⁰ i i-on,? I _u ^ groups are inactivated jugieul Table _8 group _yo circle "^ eu and the _ grinding-dance. Polishing characterized in that it is selected from forming materials and gases which do not react pad.

[Claim 6]

The liquid material of claim 4, wherein the liquid substance constituting the liquid microelement is any one selected from the group consisting of aliphatic mineral oil, aromatic mineral oil, silicone oil having no hydroxyl group at the end of the molecule, soybean oil, palm oil, palm oil, cottonseed oil, camellia oil, and hydrogenated oil. A polishing pad, characterized in that a mixture thereof.

[Claim 7]

The method of claim M, wherein the polishing layer is a first porous pore by the liquid microelement, the size of the first porous pore is larger than the injection of the inert gas the injection of the capsular foam, the injection of the chemical blowing agent A polishing pad comprising a second porous pore formed by at least one.