JP7281502B2 - Polishing pad dresser and manufacturing method thereof - Google Patents

Description

The present invention relates to polishing pad dressers and methods of making same, and more particularly to chemical mechanical polishing (CMP).

Chemical-mechanical polishing (CMP) is a very important procedure in the semiconductor manufacturing process.Besides producing wafers of appropriate size, CMP also planarizes the wafer surface for the subsequent production of integrated circuits. can. CMP can use a polishing slurry and a polishing pad, the liquid of the polishing slurry is corrosive, and the particles inside fill the grooves of the polishing pad and are fixed, and then provide mechanical friction when the polishing pad rotates. By polishing the wafer with the polishing agent, the surface roughness of the wafer is reduced and a polishing effect is obtained.

However, after a period of use, the build-up of debris and hardened abrasive slurry on the polishing pad causes the surface to "glazing" or harden, i.e., the grooves become filled with hardened abrasive slurry and replaced with new ones. The inability to retain the medium particles of the filled polishing slurry reduces the polishing effect. When the polishing slurry on the surface of the polishing pad hardens to a certain degree, projections are formed, which impairs the roughness of the entire wafer surface during polishing, and the effect of flattening the wafer cannot be obtained. Hence, the polishing pad is dressed with a polishing pad dresser (also called a pad conditioner, diamond dresser) to restore the original working surface of the polishing pad by removing surface deposits, thereby prolonging the life of the polishing pad. and reduce replacement costs.

However, abrasive particles are placed on the working surface of the polishing pad dresser, and after a long period of polishing, the abrasive particles cannot be retained due to abrasion of the working surface, which causes the abrasive particles to come off and be displaced. rice field. If the abrasive particles that fall off remain on the polishing pad, they will scratch the wafer, and the misaligned abrasive particles will cause uneven dressing of the polishing pad, thereby affecting the CMP manufacturing process. Therefore, how to protect the surface of the polishing pad dresser from wear and maintain the quality of the abrasive particles is a technical problem to be solved by the polishing pad dresser.

An object of the present invention is to provide a polishing pad dresser comprising a base material, a polishing layer, and a protective layer. The abrasive layer covers the surface of the base material and includes a bonding layer and a plurality of abrasive particles embedded in the bonding layer, each abrasive particle being exposed from the bonding layer and subjected to an insulating treatment. Equipped with protrusions. The protective layer covers the surface of the bonding layer, and the protrusions are exposed outside the protective layer.

In a preferred embodiment, the protective layer is formed from an electrodeposition coating composition, the electrodeposition coating composition contains a main resin, and the main resin is an epoxy resin, an acrylic resin, a polybutadiene resin, a polyester resin, or a polyamide resin. be.

In preferred embodiments, the substrate is a metal substrate, a metal alloy substrate, a stainless steel substrate or a die steel substrate.

In preferred embodiments, the bonding layer is a brazing material, an electroplating material, a ceramic material, a metallic material or a polymeric material.

In preferred embodiments, the abrasive particles are one or more abrasive particles selected from the group of natural diamond, synthetic diamond, polycrystalline diamond, cubic boron nitride, alumina and silicon carbide.

すなわち、前記切削力（ＣＲ_completed）と前記保護層で覆われていない研磨パッドドレッサーの切削力（ＣＲ_initial）との変化率が１０％未満である。 In a preferred embodiment, the polishing pad dresser has a cutting force (CR _completed ) that, when compared to the cutting force (CR _initial ) of a polishing pad dresser not covered with a protective layer, meets the following equation:

That is, the rate of change between the cutting force (CR _completed ) and the cutting force (CR _initial ) of the polishing pad dresser not covered with the protective layer is less than 10%.

Another object of the present invention is to provide a method of manufacturing a polishing pad dresser including the following steps (a) to (d). (a) providing a substrate; (b) a bonding layer on a surface of said substrate; and a plurality of abrasive particles embedded in said bonding layer, each said abrasive particle being on said bonding layer; forming a polishing layer having exposed projections; (c) insulating said projections; (d) electrodepositing a protective layer on the surface of said bonding layer and protecting said insulation-treated projections; The process of exposing the layer to the outside.

In a preferred embodiment, the insulation treatment includes physical insulation or chemical insulation.

In a preferred embodiment, the physical insulation includes sandblasting or plasma insulation.

In a preferred embodiment, the chemical insulation includes etching insulation.

In a preferred embodiment, the etching method uses a chemical solution to etch, wherein the chemical solution includes nitric acid, aqua regia, hydrofluoric acid, sulfuric acid, hydrogen peroxide, perchloric acid, hydrochloric acid, ferric chloride, It contains one or more ingredients selected from the group of acetic acid and ceric ammonium nitrate.

In a preferred embodiment, the bonding layer is formed by electroplating or brazing.

Compared with the prior art, the polishing pad dresser of the present invention comprises a protective layer and protrusions of abrasive particles exposed outside the protective layer, wherein the protective layer prevents bonding layer metal (e.g., nickel) from being removed during the CMP process. It can prevent deposition, so it can prevent contamination, protect the bonding layer from wear damage, hold abrasive particles, prevent abrasive particles from falling off or shifting, and protect abrasive particle protrusions. Since it is exposed to the outside of the layer, the polishing effect and life of the polishing pad dresser can be maintained. In the method of manufacturing the polishing pad dresser of the present invention, the projections of the abrasive particles are subjected to an insulation treatment, and then a protective layer is electrodeposited. Since the protective layer is not covered with the protrusions, the cutting force of the polishing pad dresser can be maintained, and the protective layer completed by electrodeposition has the advantage of being thin and evenly distributed, thus protecting the bonding layer. In addition, the height of the projection can be adjusted and maintained as required.

1 is a schematic diagram showing a polishing pad dresser of the present invention; FIG. It is a schematic diagram which shows the manufacturing method of the polishing pad dresser of a comparative example. It is a schematic diagram which shows the manufacturing method of the polishing pad dresser of this invention. 2 is a photograph taken with a scanning electron microscope (SEM) of the surface of the polishing layer of the polishing pad dresser of Example and Comparative Example 1 (FIG. (a) is the surface of the polishing layer of the polishing pad dresser of Comparative Example 1; FIG. (b) is the polishing layer surface of the polishing pad dresser of the example.)

The following embodiments should not be viewed as unduly limiting the invention. Persons of ordinary skill in the art to which this invention pertains can modify and vary the examples discussed herein without departing from the spirit or scope of the invention, and such modifications and variations may be incorporated herein. covered by the scope of the invention.

As used herein, the terms "a" and "a" refer to one or more than one (ie, at least one) of the configurations.

As shown in FIG. 1, the polishing pad dresser of the present invention comprises a substrate 1, a polishing layer 2, and a protective layer 3. The abrasive layer 2 covers the surface of the substrate 1 and includes a bonding layer 21 and a plurality of abrasive particles 22 embedded in the bonding layer 21, each abrasive particle 22 being exposed from the bonding layer 21. and has a protrusion 221 that is insulated. The protective layer 3 covers the surface of the bonding layer 21 and the protrusions 221 are exposed outside the protective layer 3 .

FIG. 2 is a diagram showing a manufacturing method of a polishing pad dresser of a comparative example. After embedding the abrasive particles 22 in the bonding layer 21, a protective layer 3 is applied on the surfaces of the abrasive particles 22 and the bonding layer 21. As shown in FIG. do. However, as a result of repeated experiments by the present inventors, when manufacturing a polishing pad dresser, any bonding method (such as brazing, electroplating/electrodeposition, or sintering) is used to bond the abrasive particles 22 together. Residues of brazing, electroplating or sintering material during the bonding process of the abrasive particles 22, even when embedded and fixed in the layer 21, render the abrasive particles 22 electrically conductive after they are fixed in the bonding layer 21. Therefore, in the next step, when the protective layer 3 is coated or covered with the bonding layer 21 by an electrodeposition method, the conductive abrasive particles 22 are covered with the protective layer 3 so that the protective layer 3 cannot be exposed outside the Compared with the polishing pad dresser without the protective layer 3, the cutting force of the polishing pad dresser with the protective layer 3 is reduced by covering the abrasive particles 22 with the protective layer 3, thus reducing the cutting force of the entire polishing pad dresser. The protective layer 3 which lowers and covers the abrasive particles 22 is easy to peel during the polishing of the polishing pad dresser, causing impurities to fall onto the polishing pad, affecting the polishing quality.

Unlike the manufacturing method of the polishing pad dresser of the comparative example, as shown in FIG. (b) comprising a bonding layer 2 on the surface of said substrate 1 and a plurality of abrasive particles 22 embedded in said bonding layer 2, each said abrasive particle 22 being on said bonding layer 21; (c) applying insulation treatment to the projections 221 (the insulation treatment shown in FIG. (d) Electrodepositing a protective layer 3 on the surface of the bonding layer 21 and applying the insulation treatment to the projections 221; is exposed to the outside of the protective layer 3. In the step (c), since the protrusions 221 were subjected to an insulation treatment, the surfaces of the protrusions 221 were completely insulated. The charged resin pellet is moved to the surface of the charging electrode on the opposite side under the action of an electric field, and the surface of the projection 221 is insulated, so that the protective layer 3 cannot be formed on the surface of the projection 221, and the The protrusions 221 are exposed outside the protective layer 3 so that the abrasive particles 22 can maintain the original cutting force, and the peeling of the protective layer 3 during polishing does not cause impurities. . In addition, when the protective layer 3 covers the bonding layer 21 , it protects the bonding layer 21 from damage caused by friction during polishing, so that the bonding layer 21 firmly holds the abrasive particles 221 and the abrasive particles 221 and the polishing slurry in CMP is usually corrosive, such as an acid etchant, and said protective layer 3 is a metal (eg, nickel ) deposition to prevent contamination.

すなわち、前記切削力（ＣＲ_completed）と前記保護層で覆われていない研磨パッドドレッサーの切削力（ＣＲ_initial）との変化率が１０％未満である。本発明の研磨パッドドレッサーの製造方法で製造された研磨パッドドレッサーは、前記保護層３を前記結合層２１に電着した後、前記研磨パッドドレッサーの切削力にほとんど影響を及ぼさない。本発明の研磨パッドドレッサーの切削力は、３００μｍ／ｈｒ以上であり、好ましくは３２０μｍ／ｈｒ以上であり、より好ましくは３３０μｍ／ｈｒ以上であり；上記切削力は、一例であり、限定するものではなく、本発明の属する技術分野における通常の知識を有する者は、必要に応じて所望の研磨パッドドレッサーの切削力を調整して得ることができる。 Through tests, the polishing pad dresser of the present invention has a cutting force (CR _completed ), and the cutting force (CR _initial ) of the polishing pad dresser not covered with the protective layer 3 (that is, the bonding layer 21 does not have the protective layer 3), the rate of change of the cutting force fits the following equation.

That is, the rate of change between the cutting force (CR _completed ) and the cutting force (CR _initial ) of the polishing pad dresser not covered with the protective layer is less than 10%. The polishing pad dresser manufactured by the manufacturing method of the polishing pad dresser of the present invention hardly affects the cutting force of the polishing pad dresser after the protective layer 3 is electrodeposited on the bonding layer 21 . The cutting force of the polishing pad dresser of the present invention is 300 μm/hr or more, preferably 320 μm/hr or more, more preferably 330 μm/hr or more; However, a person having ordinary knowledge in the technical field to which the present invention belongs can obtain a desired cutting force of the polishing pad dresser by adjusting it as necessary.

The following describes the materials and manufacturing methods used to construct the polishing pad dresser of the present invention. The materials and techniques disclosed herein are exemplary only, and other materials and techniques not described can be used without departing from the scope of the invention.

In the polishing pad dresser of the present invention, the substrate 1 is made of one or more of stainless steel, metal material, plastic material and ceramic material. In fact, said substrate 1 only needs to be able to bear the polishing layer 2, and preferably the material can be a metal substrate, a metal alloy substrate, a stainless steel substrate or a die steel substrate. Specifically, the metal substrate includes, but is not limited to, copper, iron, aluminum, titanium or tin; the metal alloy substrate includes iron alloy, copper alloy, aluminum alloy, titanium alloy or magnesium alloy. Including but not limited to.

In the polishing pad dresser of the present invention, the bonding layer 21 is used to place between the layers of the abrasive particles 22 and is attached to the substrate 1, and the abrasive particles 22 are mainly attached to the bonding layer 21. Embedded and fixed. The bonding layer 21 can be made of various materials, such as resin organic bonding method, electroplating method, electrodeposition by brazing method, and the material is brazing material, electroplating material, ceramic material, metal material or polymer material. and the invention is not limited thereto. Specifically, the brazing material, the electroplating material, or the metal material includes at least one selected from the group consisting of iron, cobalt, nickel, chromium, manganese, silicon, aluminum, and combinations thereof; Said polymeric materials include epoxy resins, polyester resins, polyacrylic resins or phenolic resins; said ceramic materials include various metal oxides, nitrides, carbides, borides, silicides or combinations thereof such as silicon carbide, silicon nitride, aluminum nitride, alumina, titanium carbide, titanium diboride or boron carbide).

In the polishing pad dresser of the present invention, said abrasive particles 22 are one or more abrasive particles 22 selected from the group of natural diamond, synthetic diamond, polycrystalline diamond, cubic boron nitride, alumina and silicon carbide. As used herein, the “protrusion 221 of the abrasive particle 22” means the portion of the upper end of the abrasive particle 22 that is not covered with the protective layer 3, and has an outer shape of pyramid, cone, or the like. It may be arcuate, cylindrical, edged, or prismatic, but is not limited thereto.

As used herein, "the protrusions 221 are insulated" means that the abrasive particles 22 are embedded and fixed in the bonding layer 21 through a bonding process, and the protrusions 221 of the abrasive particles 22 are is electrically conductive due to the residue of brazing, electroplating or sintering materials in the bonding process, which means further insulation treatment after the bonding process, said insulation treatment being physical insulation or chemical insulation. mentioned. The physical insulation includes insulation by sandblasting or plasma, the principle of which is to use sandblasting or plasma to cleanly remove the conductive material on the protrusion 221, so that it has no conductivity. The sandblasting particles used in the sandblasting method have a particle size of about 50 to 200 μm, and the temperature of the plasma method is about 150 to 350°C. The chemical insulation includes insulation by an etching method, the etching method etching with a chemical solution, and removing the conductive material on the protrusion 221 after etching with the chemical solution; the chemical solution includes nitric acid and aqua regia. , hydrofluoric acid, sulfuric acid, hydrogen peroxide, perchloric acid, hydrochloric acid, ferric chloride, acetic acid, ceric ammonium nitrate, potassium chloride, potassium iodide, ammonium persulfate, ammonium chloride or combinations thereof, but these is not limited to Said chemical solution comprises one or more components selected from the group of nitric acid, aqua regia, hydrofluoric acid, sulfuric acid, hydrogen peroxide, perchloric acid, hydrochloric acid, ferric chloride, acetic acid and ceric ammonium nitrate. is preferred. After the above-described insulation treatment, the surface of the projection 221 is insulated and is not charged, and the protective layer 3 cannot be electrodeposited on the surface of the projection 221 thereafter. can be exposed to

In the polishing pad dresser of the present invention, the protective layer 3 is preferably formed of an electrodeposition coating composition, electrodeposition is a kind of surface treatment, the polishing pad dresser is immersed in the electrodeposition coating composition, and the The polishing layer 2 is placed between the electrodes and an electric current is applied to deposit the electrodeposition coating composition on the surface of the bonding layer 21 by electrical action to form a uniform protective layer 3 . Although other surface treatments (such as spray coating and spin coating) can also be used, electrodeposition coating can be used to obtain a uniform and thin protective layer 3; , which is advantageous for maintaining the cutting force of the abrasive particles 22 . The thickness of the protective layer 3 is preferably 10 to 30 μm, but is not limited, and the thickness difference at each position is preferably controlled to 1.0 to 3.0 μm, more preferably 1.5 μm. be. The electrodeposition coating composition contains a main resin, and the main resin is an epoxy resin, an acrylic resin, a polybutadiene resin, a polyester resin, or a polyamide resin. Specific examples include amine-modified epoxy resins (for example, modified epoxy resins containing diethyltriamine), acrylic resins containing carboxyl groups and hydroxyl groups, and epoxidized polybutadiene resins, but the present invention is not limited thereto.

The following examples provide methods of making the polishing pad dresser of the present invention. It should be understood that the examples are for illustrative purposes only and are not intended to limit the invention.

Example - Polishing Pad Dresser with Insulated Protrusions of the Present Invention A polishing layer was formed on the surface of stainless steel with molten nickel-chromium alloy and diamond particles, and the molten nickel-chromium alloy was applied to each diamond particle by surface tension. Part of the side surface is covered, and the diamond grains are embedded, supported, and fixed. An insulation treatment is applied to the protrusions of each diamond particle by plasma method to insulate the surface of the protrusions. Finally, an epoxy resin (manufactured by US Industries, Inc. (PPG)) was electrodeposited on the surface of the bonding layer to form a protective layer to obtain the polishing pad dresser of the present invention.

Comparative Example 1 - Polishing Pad Dresser with No Insulation Treatment for Protrusions The manufacturing method of the polishing pad dresser of Comparative Example 1 is the same as that of the Example, and the difference is that Comparative Example 1 performs insulation treatment on the protrusions of each diamond particle. is not applied.

結果は、下表１に示す。

Test 1. Cutting Force The cutting forces of the polishing pad dressers of Example and Comparative Example 1 were tested, and the rate of change in cutting force was calculated using the following formula.

The results are shown in Table 1 below.

As shown in Table 1, the rate of change in cutting force after covering the bonding layer of the polishing pad dresser of the example with the protective layer was less than 10%, which is less than that of the example even when covered with the protective layer. It shows that the cutting force of the polishing pad dresser does not decrease. In contrast, after the polishing layer of the polishing pad dresser of Comparative Example 1 was covered with the protective layer, the rate of change in cutting force exceeded 10% and decreased from 318 μm/hr to 202 μm/hr. The difference between Example and Comparative Example 1 is whether or not the protective layer covers the projections of the diamond grains. As can be seen from Comparative Example 1, when the protective layer covered the protrusions, the cutting force of the polishing pad dresser was significantly reduced.

Test 2. Imaging of Surface of Polishing Layer of Polishing Pad Dresser with Scanning Electron Microscope (SEM) FIG. 4A shows the polishing layer surface of the polishing pad dresser of Comparative Example 1, and FIG. 4B shows the polishing layer surface of the polishing pad dresser of Example. As shown in FIG. 4(b), the projections of the abrasive particles of the polishing pad dresser of Example have sharp cutting edges because the protective layer cannot be electrodeposited on the surface due to the insulation treatment. In contrast, as shown in FIG. 4(a), the protrusions of the abrasive particles of the polishing pad dresser of Comparative Example 1 were not insulated, and the protective layer was electrodeposited on the surface. It is dull and does not have a sharp cutting edge.

Comparative example 2. Polishing pad dresser without protective layer A polishing layer is formed on the surface of stainless steel with molten nickel-chromium alloy and diamond particles, and the molten nickel-chromium alloy is covered by a part of the oblique side of each diamond particle by surface tension, said A polishing pad dresser without a protective layer was obtained when diamond particles were embedded, supported and fixed.

Test 3. Comparison of Metal Deposition The polishing pad dressers of Example and Comparative Example 2 were each immersed in a 3% nitric acid solution, and the amount of metal in the 3% nitric acid solution after immersion was tested 24 hours later. The results are shown in Table 2 below. .

As shown in Table 2, the stock 3% nitric acid solution contained low concentrations of chromium, iron, nickel, and cobalt, and after the polishing pad dresser of the example was soaked, the chromium, iron, nickel, and cobalt concentrations were low. There was precipitation, but the concentration was not high. In contrast, the polishing pad dresser of Comparative Example 2 had very high deposition concentrations of chromium, iron, nickel and cobalt due to the absence of the protective layer.

In the polishing pad dresser manufactured by subjecting the projections of the above specific examples to insulation treatment, since the projections of the diamond particles are not covered with a protective layer, the cutting force can be maintained and the polishing effect may be reduced. It is possible to maintain the polishing power of the polishing pad dresser. Also, if the bonding layer of the polishing pad dresser is covered with a protective layer, the bonding layer metal can be protected from deposition.

In summary, the polishing pad dresser of the present invention has a protective layer, and the protective layer can prevent the deposition of the metal (eg, nickel) of the bonding layer during the CMP process, thus preventing contamination. It can protect the bonding layer from damage due to abrasion, hold the abrasive particles, prevent the shedding or displacement of the abrasive particles, and peeling of the protective layer during polishing of the polishing pad dresser, causing impurities to damage the polishing pad. Since there is no falling situation, the polishing effect and life of the polishing pad dresser can be maintained. It should be noted that, in the manufacturing method of the polishing pad dresser of the present invention, an insulation treatment and electrodeposition are used, and the insulation treatment insulates the projections of the abrasive particles so that the protective layer is not covered with the projections during subsequent electrodeposition. The protective layer completed by electrodeposition has the advantage of being thin and evenly distributed, so that the height of the protrusions can be maintained, ie the cutting force of the polishing pad dresser can be maintained. Therefore, the polishing pad dresser of the present invention is suitable for use in CMP and has industrial applicability.

Although the present invention has been described in detail above, the above descriptions are only preferred embodiments of the present invention, and the scope of implementation of the present invention cannot be limited thereby, i.e., the scope of the claims of the present invention. Variations and embellishments made on the basis within the equivalent range are covered by the protection scope of the present invention.

REFERENCE SIGNS LIST 1 substrate 2 abrasive layer 21 bonding layer 22 abrasive particles 221 projections 3 protective layer 4 plasma nozzle

Claims (7)

The steps of (a) providing a substrate,
(b) polishing comprising a bonding layer on the surface of the substrate and a plurality of insulating abrasive particles embedded in the bonding layer, each abrasive particle having a protrusion exposed above the bonding layer; forming a layer;
(c) applying a physical insulation treatment to each of all said projections;
(d) electrodepositing a protective layer on the surface of the bonding layer and exposing the physically insulated protrusions outside the protective layer;
The physical insulation treatment is a treatment for removing conductive residues generated in the step of forming the polishing layer,
The method for manufacturing a polishing pad dresser, wherein the physical insulation treatment includes insulation treatment by a sandblast method or a plasma method. The manufacturing method according to claim 1, wherein the bonding layer is formed by an electroplating method or a brazing method. Obtained by the production method according to claim 1 or 2,
a substrate;
covering the surface of the substrate and comprising a bonding layer and a plurality of insulating abrasive particles embedded in the bonding layer, each abrasive particle being exposed from the bonding layer to form an abrasive layer; a polishing layer provided with said projections , each of which undergoes a physical insulation treatment, including a sandblasting or plasma insulation treatment, to remove the conductive residue produced in the
a protective layer covering the surface of the bonding layer and having the projections exposed outside the protective layer;
with
The cutting force (CR _completed ) and the polishing pad dresser not covered with the protective layer are compared with the cutting force (CR _initial ) of the polishing pad dresser not covered with the protective layer, which has the cutting force (CR _completed ). with the cutting force (CR _initial ) of less than 10%. 4. According to claim 3, wherein the protective layer is formed from an electrodeposition coating composition, and the electrodeposition coating composition contains a main resin, and the main resin is an epoxy resin, an acrylic resin, a polybutadiene resin, a polyester resin, or a polyamide resin. Polishing pad dresser as described. 5. The polishing pad dresser according to claim 3 or 4, wherein said substrate is a metal substrate, a metal alloy substrate, a stainless steel substrate or a die steel substrate. The polishing pad dresser according to any one of claims 3 to 5, wherein the bonding layer is brazing material, electroplating material, ceramic material, metallic material or polymeric material. The abrasive according to any one of claims 3 to 6, wherein said abrasive particles are one or more abrasive particles selected from the group of natural diamond, synthetic diamond, polycrystalline diamond, cubic boron nitride, alumina and silicon carbide. pad dresser.

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