JP2006019641A - Polishing method of semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the flatting method of a metal film formed on a semiconductor wafer capable of polishing the metal film even under a low polishing pressure condition at a high speed, and capable of suppressing the occurrence of polishing surface defects such as scratches and dishing in a process flatting the metal film formed on the semiconductor wafer and a manufacturing method of the semiconductor wafer. <P>SOLUTION: The method is for chemically and mechanically polishing the metal film formed on the semiconductor wafer using such a metal polishing composition that polyoxo acid, an anionic surface-active agent and water are contained by using a chemical and mechanical device provided with a polishing pad. In the method, the polishing pad is provided with holes for supplying the metal polishing composition onto the polishing pad surface, and the chemical and mechanical polishing device is provided with a device for supplying the metal polishing composition onto the polishing pad surface through the holes of the polishing pad. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polishing composition used for polishing a metal film formed on a semiconductor wafer, a polishing apparatus, and a method for polishing a metal film formed on a semiconductor wafer using the same.

Due to the rapid development of LSI technology, integrated circuits are increasingly miniaturized and multi-layered. Multi-layer wiring in integrated circuits is a factor that causes extremely large irregularities on the surface of the semiconductor. This, combined with the miniaturization of integrated circuits, leads to disconnection, lower capacitance, and electromigration, resulting in reduced yield and reliability. This is the cause of the problem.
For this reason, various processing techniques for flattening metal wirings and interlayer insulating films in multilayer wiring wafers have been developed so far, one of which is CMP (Chemical Mechanical Polishing) technique. The CMP technique is a technique required for planarizing an interlayer insulating film, forming an embedded wiring, forming a plug, and the like in semiconductor manufacturing. CMP is performed by rotating each of the carrier and the polishing pad while pressing a flat semiconductor wafer made of a normal semiconductor material mounted on the carrier against the wet polishing pad with a constant pressure. At this time, the convex portions of the wiring and the insulating film are polished and planarized by the polishing composition introduced between the semiconductor wafer and the polishing pad.

  Conventionally, various polishing compositions and polishing methods have been proposed for polishing a metal film formed on a semiconductor wafer. As shown in “Semiconductor planarization CMP technology” by Toshiro Tohi et al. (Published by the Industrial Research Council in July 1998), page 235, metal CMP oxidizes the metal surface with an oxidizing agent in the polishing composition. On the other hand, polishing is performed with a polishing pad and abrasive grains under conditions in which the metal is slightly corroded (etching) by making the pH acidic. For example, as a polishing composition for a metal film such as aluminum formed on a semiconductor wafer, a polishing composition in which aluminum oxide is dispersed in an aqueous nitric acid solution having a pH of 3 or lower (see, for example, US Pat. No. 4,702,792) ), And a polishing composition obtained by mixing aluminum oxide or silicon oxide with an acidic aqueous solution such as sulfuric acid, nitric acid, and acetic acid (see, for example, US Pat. No. 4,944,836). Also, a polishing composition in which aluminum oxide is dispersed in hydrogen peroxide and a phosphoric acid aqueous solution (for example, see US Pat. No. 5,209,816), abrasive grains such as aluminum oxide or silicon oxide, hydrogen peroxide A polishing composition comprising an oxidizing agent such as is usually used.

  However, when aluminum oxide is used to planarize the metal film formed on the semiconductor wafer, the α type shows a high polishing rate, but defects such as micro scratches and orange peel occur on the surface of the metal film and insulating film. There was something to do. On the other hand, when abrasive grains such as γ-type, amorphous alumina, or silicon oxide are used, the occurrence of defects such as micro scratches and orange peel on the surface of the metal film or insulating film can be suppressed. There was a problem that a sufficient polishing rate could not be obtained. Thus, the polishing composition in which abrasive grains made of a metal oxide such as aluminum oxide or silicon oxide are dispersed in an aqueous solution has a problem of surface scratches due to poor dispersibility of the abrasive grains themselves. In addition, when hydrogen peroxide, which is a liquid oxidizing agent, is used as described above, or when an etching agent such as ammonium persulfate is used (for example, see JP-A-6-313164), wet etching is excessive. There is a problem in practical use such as dishing (a phenomenon in which the central portion of the metal film (d) in FIG. 1D is excessively polished from the peripheral portion) and defects such as pits and voids are generated.

  In order to improve this, a method of adding a chemical reagent (such as an anticorrosive agent or a chelating agent) that forms a protective film on the surface of the metal film in the polishing composition has also been proposed (for example, JP-A-8-83780, (See JP-A-11-195628). However, when such chemical reagents are used, the etching is surely suppressed and the occurrence of dishing can be prevented. However, since a protective film is also formed on the portion to be polished, the polishing rate is extremely reduced. Occurs. Attempts have been made to optimize the use of etching agents and chemical reagents to prevent this, but it is difficult to find conditions that satisfy the performance of both, and the results are reproducible because they are also susceptible to process conditions. There is a problem that cannot be obtained.

In addition, in order to obtain a high polishing rate of 400 nm / min or more, the protective film is also removed at a high polishing pressure of 200 g / cm ² or more (see, for example, Japanese Patent Application Laid-Open No. 2000-252242). When a porous low dielectric constant insulating film that is predicted to be used is used for manufacturing a semiconductor wafer, there is a problem with the strength of the insulating film. Occur.
In addition, if the polishing pressure is increased and mechanical polishing with the pad is performed, it becomes more susceptible to the influence of the pad surface at the time of polishing. It becomes.

  By the way, polyoxoacids, especially heteropolyacids, have a strong acidity and oxidation action as described in the “Chemistry of Polyacids” edited by the Chemical Society of Japan (August 1993, published by the Society Press). For example, Japanese Patent Application Laid-Open No. 9-505111 discloses that it is used for metal passivation treatment and etching. Examples in which a heteropoly acid is actually applied as an etching agent for a semiconductor surface (Applied Surface Science vol. 135, No. 1/4, pp65-70 (1998.10.8)), or a polyoxo acid or a salt thereof as an etching agent for polishing Attempts have also been made (see, for example, Japanese Patent Application Laid-Open No. 2000-119639). In particular, in the latter case, when only polyoxo acid or a salt thereof is used as a polishing etchant (first polishing composition) and when a known abrasive is further added as an abrasive (second polishing composition). Two usages are described.

  In the case of the first polishing composition, when the heteropolyacid is used alone as an etching agent for polishing a metal film, the heteropolyacid is soluble in water and thus acts as a liquid oxidizing agent. Both performances cannot be satisfied. That is, when the concentration of the heteropolyacid is increased in order to increase the polishing rate, etching progresses simultaneously and dishing occurs. On the other hand, when a basic substance such as ammonia is allowed to act on the heteropolyacid to be used as a heteropolyacid salt, etching is suppressed, but at the same time, the polishing rate is reduced. Therefore, for the purpose of increasing the polishing rate, it has been proposed that this type of first polishing composition contains an abrasive to form a second polishing composition. In this case, too, the above-described first polishing composition and Similarly, it is difficult to suppress the occurrence of dishing by the progress of etching. Therefore, it does not meet the purpose of obtaining a high polishing rate at a low polishing pressure while suppressing the occurrence of dishing.

Further, as an improvement of the polishing apparatus, chemical mechanical polishing for polishing the semiconductor wafer by relatively moving the polishing pad and the semiconductor wafer with a polishing liquid interposed between the polishing pad and the semiconductor wafer. In the apparatus, there has been reported a chemical mechanical polishing apparatus characterized in that the polishing pad is provided with a hole for supplying a polishing liquid to the surface of the polishing pad (see, for example, JP-T-2004-505435). When the chemical mechanical polishing apparatus according to the present invention was used, dishing was suppressed, but the polishing rate was insufficient (generally 300 nm / min or less).
US Pat. No. 4,702,792 US Pat. No. 4,944,836 US Pat. No. 5,209,816 JP-A-6-313164 JP-A-8-83780 JP-A-11-195628 JP 2000-252242 A JP-A-9-505111 JP 2000-119639 A JP 2004-505435 A Toshiro Tohi et al., “Semiconductor planarization CMP technology”, first edition, published by Industrial Research Council, July 15, 1998, page 235 The Chemical Society of Japan, “Chemistry of Polyacids”, first edition, Society Publishing Center, August 25, 1993, 86-87, 112-123 A. Rothschild, C.I. Debemme-Chouvy, A.M. Etcheberry, “Study of the interaction at rest potential between silicotungstantiopolyolation solution and GaAs surface, April, 1998. 135, no. 1/4, pp65-70

  According to the present invention, a metal film formed on a semiconductor wafer can be polished at high speed even under a low polishing pressure, and the etching property causing dishing is controlled to a low level, and at the same time, scratch and erosion (FIG. 1D) And a method for polishing a metal film formed on a semiconductor wafer capable of suppressing the occurrence of defects on the surface to be polished, such as a phenomenon in which the insulating film (b) around the metal film (d) is polished) It aims at providing the manufacturing method of. The semiconductor wafer polishing method includes from the stage of loading a semiconductor wafer before polishing into the polishing apparatus to the stage of removing the polished semiconductor wafer from the apparatus.

  As a result of intensive studies to solve the above problems, the present inventors have found that a metal polishing composition comprising a polyoxoacid, an anionic surfactant and water, and the polishing pad converts the metal polishing composition into the polishing pad. Conventionally, it has been difficult to use a chemical mechanical polishing apparatus having a hole for supplying to the surface and a device for supplying the metal polishing composition to the surface of the polishing pad through the hole of the polishing pad. It has been found that it is possible to achieve both a high etching rate at a low polishing pressure while suppressing etching and dishing, and it is effective in polishing a metal film formed on a semiconductor wafer. That is, the present invention is as follows.

1) Chemical mechanical polishing apparatus comprising a polishing pad for a metal film formed on a semiconductor wafer using a metal polishing composition comprising polyoxoacid, an anionic surfactant and water In the method of chemical mechanical polishing by pressing the metal film surface against the polishing pad, the polishing pad has a hole for supplying the metal polishing composition to the polishing pad surface, and the chemical mechanical polishing An apparatus includes an apparatus for supplying the metal polishing composition to the surface of the polishing pad through a hole in the polishing pad, and supplying the metal polishing composition between the metal film and the polishing pad during polishing from the hole. A method for polishing a semiconductor wafer.
2) The semiconductor wafer polishing method of the invention of 1), wherein the polyoxoacid is a heteropolyacid. 3) The chemical mechanical polishing apparatus holds a support base connected to orbitally move the polishing pad and a semiconductor wafer. The method for polishing a semiconductor wafer according to 1) or 2) further comprises a carrier for pressing a metal film surface on the semiconductor wafer against the polishing pad.

4) The method for polishing a semiconductor wafer according to 3), wherein the carrier is a front reference carrier.
5) The method for polishing a semiconductor wafer according to 3), wherein the carrier is a back reference carrier.
6) The method for polishing a semiconductor wafer according to any one of 3) to 5), wherein the polishing pad is orbited horizontally with respect to the semiconductor wafer with the orbital radius of less than 4 mm.
7) The method for polishing a semiconductor wafer according to any one of 3) to 6), wherein the polishing pad is orbited at an orbital speed exceeding 400 rpm.

8) The method of polishing a semiconductor wafer is
(A) loading a semiconductor wafer onto a carrier (i) placing the semiconductor wafer close to the polishing pad (iii) pressing the semiconductor wafer against the polishing pad (e) orbiting the polishing pad The semiconductor wafer according to any one of the inventions 1) to 7), comprising the steps of (1) to (5), and (ii) removing the semiconductor wafer from the polishing pad in the order of Polishing method.

9) The method for polishing the semiconductor wafer comprises:
(8) The method for polishing a semiconductor wafer according to (8), comprising a step of rotating the semiconductor wafer before removing the semiconductor wafer from the polishing pad.
10) The method for polishing the semiconductor wafer includes (i) rotating the semiconductor wafer alternately clockwise and counterclockwise before removing the semiconductor wafer from the polishing pad 8) A method for polishing a semiconductor wafer according to the present invention.
11) In the polishing method of the semiconductor wafer, the step (iii) applies a first pressure to a central zone on the back surface of the semiconductor wafer, and the first pressure is applied to a peripheral zone concentric with the central zone. 8) The method for polishing a semiconductor wafer according to 8), comprising a step of applying a second pressure different from that of the invention.

  According to the method for manufacturing a semiconductor wafer of the present invention, it is possible to polish a metal film such as a copper film at a high speed even under a low polishing pressure, while suppressing the generation of etching, dishing, erosion and scratches, which has been difficult with the prior art. It becomes possible.

The present invention will be specifically described below.
In the present invention, the low polishing pressure means about 150 g / cm ² or less, and the high-speed polishing means a polishing rate of about 450 nm / min or more.
The present invention is applied to polishing and planarization of a metal film formed on a semiconductor wafer. The metal film formed on the semiconductor wafer to be polished is a known metal film for wiring, plug, contact metal layer, barrier metal layer, for example, aluminum, copper, tungsten, titanium, tantalum, aluminum alloy And a metal film selected from the group consisting of copper alloy, titanium nitride, tantalum nitride, and the like. In particular, application to a metal film made of copper and a copper alloy having a low surface hardness and easily causing defects such as scratches and dishing is recommended.
As shown in FIG. 1C, for the semiconductor wafer obtained by embedding the metal film for wiring (d), an extra metal film other than the grooves or openings as shown in FIG. It removes and planarizes by grind | polishing using the polishing composition of this invention.

Hereinafter, an outline of an example of a method for manufacturing a semiconductor wafer will be described.
First, as shown in FIG. 1A, after an insulating film (b) is formed on a semiconductor wafer (a) such as a silicon wafer, a groove for metal wiring is formed in the insulating film (b) by photolithography and etching. Alternatively, an opening for connection wiring is formed. Next, as shown in FIG. 1B, a barrier metal layer made of titanium nitride (TiN), tantalum nitride (TaN) or the like is formed in the groove or opening formed in the insulating film (b) by a method such as sputtering or CVD. c). Next, as shown in FIG. 1C, a metal film (d) for wiring is embedded so that the thickness is equal to or greater than the height of the groove or opening formed in the barrier metal layer (c). Next, as shown in FIG. 1D, the excess metal film (d) other than the grooves or openings is removed by a method of polishing using the polishing composition of the present invention. Furthermore, by forming an insulating film on the obtained flattened surface and repeating the above method as many times as necessary, a semiconductor wafer having a multilayer wiring structure as an electronic component can be obtained.

  The metal polishing composition used in the method for producing a semiconductor wafer of the present invention comprises a polyoxoacid, an anionic surfactant and water. The polishing composition of the present invention includes components such as abrasive particles and additives that are usually used within a range that does not impair the effects of the present invention as described later, or according to the purpose. It is a feature that the object of the present invention can be achieved with only the above. That is, the polishing composition of the present invention is characterized by exhibiting excellent polishing performance even when substantially free of abrasive grains. Here, the phrase “substantially free of abrasive grains” refers to a state in which the proportion of the mass of abrasive grains in the total mass of the polishing composition is less than 1%.

  The polyoxo acid used in the present invention is a condensate of an oxygen acid composed of elements such as Mo, V, W, Ti, Nb, Ta, etc., and an isopoly acid and a heteropoly acid correspond to this. The isopolyacid is a condensed oxygen acid composed of a single element among the constituent elements of the polyoxoacid, and examples thereof include polymolybdic acid, polyvanadic acid, polytungstic acid, polytitanic acid, polyniobic acid, and polytantalic acid. Of these, polymolybdic acid, polyvanadic acid, and polytungstic acid are preferred from the viewpoint of the polishing rate of the resulting metal polishing composition in the present invention for metal polishing.

  The heteropolyacid is obtained by incorporating a heteroelement as a central element into the isopolyacid, and its structure is composed of a condensed coordination element, a central element and oxygen. Here, the condensed coordination element means a constituent element of the polyoxoacid, and among them, those containing at least one selected from the group consisting of Mo, W and V are mentioned as preferred examples, and other Nb, Ta Or the like. The central element of the heteropolyacid is selected from the group consisting of P, Si, As, Ge, Ti, Ce, Mn, Ni, Te, I, Co, Cr, Fe, Ga, B, V, Pt, Be, and Zn. The atomic ratio of the condensed coordination element to the central element (condensed coordination element / central element) is 2.5-12.

  Specific examples of the heteropolyacids described above include, for example, phosphomolybdic acid, silicomolybdic acid, phosphovanad molybdic acid, cayvanadomolybdic acid, lintongue molybdate, cytongusto molybdic acid, phosphovanad tungstomolybdic acid, and cayvanado tungst. Molybdic acid, phosphovanad tungstic acid, cayvanadotungstic acid, phosphorus molybdoniobic acid, boromolybdic acid, borotungstomolybdic acid, borovanadomolybdic acid, borovanad tungstic acid, cobalt molybdic acid, cobalt vanadotungstic acid, phosphorus Examples include, but are not limited to, tungstic acid, silicotungstic acid, phosphovanadic acid, and silicovanadic acid. Among the polyoxoacids, heteropolyacids are preferable from the viewpoint of sufficient acid strength and oxidizing power sufficient for etching a metal for polishing purposes, preferably phosphomolybdic acid, silicomolybdic acid, and phospho-phosphoric acid into which vanadium is further introduced. Examples thereof include nadmolybdic acid and caivanadomolybdic acid.

The polyoxo acids may be used alone or in combination. In addition, for the purpose of adjusting the acidity of the resulting polishing composition and controlling the polishing performance, it is also possible to add basic substances to these polyoxo acids and use some or all of the polyoxo acids as polyoxo acid salts. It is. Examples of polyoxo acid salts include salts of the above polyoxo acids with metals, ammonium and organic amines.
The content of the polyoxo acid in the polishing composition of the present invention is not particularly limited, but is preferably used in the range of 0.1 to 30% by mass, more preferably 0.5 to 15% by mass. It is a range. From the viewpoint of obtaining a high polishing rate, it is preferably 0.1% by mass or more, and from the viewpoint of easy dishing suppression, it is preferably 30% by mass or less.

By including an anionic surfactant in the composition of the present invention, it becomes possible to suppress the etching of the metal to be polished by polyoxo acid, and it has polishing performance such as planarization of the metal film to be polished and suppression of dishing. A polishing composition is obtained.
The anionic surfactant used in the present invention is not particularly limited. For example, fatty acid or a salt thereof, alkylsulfonic acid or a salt thereof, alkylbenzenesulfonic acid or a salt thereof, alkylsulfosuccinic acid or a salt thereof, polyoxyethylene alkylsulfuric acid Or a salt thereof, polyoxyethylene alkylarylsulfuric acid or a salt thereof, p-styrenesulfonic acid or a salt thereof, an alkylnaphthalenesulfonic acid or a salt thereof, a naphthalenesulfonic acid or a salt thereof, a naphthenic acid or a salt thereof, an alkyl ether carboxylic acid or Its salt, α-olefin sulfonic acid or its salt, N-acylmethyl taurine, alkyl ether sulfuric acid or its salt, polyoxyethylene alkyl phenyl ether sulfuric acid or its salt, alkyl ether phosphoric acid ester or its Salts, alkylphosphoric acid ester or a salt thereof, acylated peptides, formalin polycondensate, condensate of higher fatty acids and amino acids, monoglysulfate, secondary higher alcohol ethoxy sulfates, and the like dialkyl sulfosuccinate salts.

In the present invention, a saturated type that does not contain any carbon-carbon double bond (excluding a benzene ring) is preferable because it does not easily deteriorate due to oxidation and does not deteriorate over time. Alkylsulfonic acid or a salt thereof, Alkylbenzenesulfonic acid or a salt thereof, alkylsulfosuccinic acid or a salt thereof, polyoxyethylene alkylsulfuric acid or a salt thereof, polyoxyethylene alkylarylsulfuric acid or a salt thereof is preferably used. More preferably, alkylsulfonic acid, alkylbenzenesulfonic acid, alkylsulfosuccinic acid, polyoxyethylene alkylsulfuric acid, and polyoxyethylenealkylarylsulfuric acid are used.
That is, from the viewpoint of the polishing rate of the metal polishing composition in the present invention, the anionic surfactant is preferably an acid type rather than a salt.
In the present invention, the anionic surfactants can be used alone or in combination of two or more thereof.

The content of the anionic surfactant used in the polishing composition of the present invention varies depending on the type and the type and amount of the polyoxo acid (its salt) and nonionic surfactant used, but is preferably 0.00. It is used in the range of 1 to 50% by mass, and more preferably in the range of 0.3 to 20% by mass. When the amount is 0.1% by mass or more, a sufficient stabilizing effect of the composition is exhibited, and when it is 50% by mass or less, dishing is small, or there is no inconvenience such as an increase in viscosity.
The polishing composition of the present invention usually uses water as a medium. The polyoxo acid and the anionic surfactant are dissolved by stirring using a commonly used stirring blade, but it is preferable to sufficiently stir using a homogenizer, ultrasonic waves, a wet medium mill or the like.

  In the polishing composition of the present invention, the details of the polishing mechanism are not clear, but when a polishing composition in which only polyoxo acid is dissolved is used, an extremely high polishing rate is obtained due to its high etching property to the metal to be polished. Although the surface of the metal film is not flattened and severe dishing occurs, the polyoxoacid is mixed with an anionic surfactant at an appropriate ratio to obtain the polishing composition of the present invention. It was found that the etching property of the acid was suppressed, the polishing progressed only at the portion where the convex portion of the metal film to be polished was in contact with the polishing pad, a flat metal film surface was obtained, and the occurrence of dishing was also suppressed. From this, the anionic surfactant suppresses the etching property of polyoxo acid by some action, and further, the friction generated by the polishing pad and the convex part of the metal film or the high share generated in the liquid film causes the anionic surfactant to It is presumed that the effect of suppressing the etching property of polyoxo acid is hindered and only the convex portions of the metal film are polished.

  Therefore, the polishing composition of the present invention is characterized in that it does not require abrasive grains that have been conventionally added for the purpose of mechanical polishing, and is a problem derived from the abrasive grains. This eliminates scratches and sedimentation of abrasive grains. Further, in the conventional polishing composition that requires mechanical polishing with abrasive grains, it is known that the polishing rate is proportional to the polishing pressure. However, when the polishing composition of the present invention is used, the polishing rate is not polished. The polishing is not proportional to the pressure, and polishing does not proceed below a certain threshold of the polishing pressure, and a high polishing rate can be obtained rapidly at a polishing pressure exceeding the threshold. The threshold value varies depending on the composition of the polishing composition of the present invention. By selecting a composition having a low threshold value, a high polishing rate can be obtained at a low polishing pressure. Problems such as damage are resolved.

  In the present invention, it is preferable to contain an organic compound having both a nitrogen atom and a carboxyl group in the molecule from the viewpoint of suppressing dishing. Examples of organic compounds having a nitrogen atom and a carboxyl group in the molecule include cystine, glycine, glutamic acid, aspartic acid, quinaldic acid, quinolinic acid, picolinic acid, nicotinic acid, histidine, benzotriazole carboxylic acid, glutamine, glutathione, glycyl Glycine, alanine, γ-aminobutyric acid, ε-aminocaproic acid, arginine, titrulline, tryptophan, threonine, cysteine, N-acetylcysteine, oxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, phenylglycine, proline, serine, tyrosine And valine are preferable examples, and more preferable examples are quinaldic acid and histidine.

The addition amount of the organic compound having both a nitrogen atom and a carboxyl group in the molecule is 5000 ppm or less, preferably 1000 ppm or less, more preferably 200 ppm or less, from the viewpoint of polishing rate and from the viewpoint of expression of dishing suppression effect.
In the polishing composition of the present invention, the etching property of the metal film that causes dishing is extremely low, so it is not necessary to use a protective film forming agent known in the industry, but the polishing rate is lowered. Within a practically acceptable range, the protective film forming agent may be added as necessary to further suppress the etching property. Particularly when the metal is copper or a copper alloy containing copper as a main component, for example, benzotriazole, benzimidazole, tolyltriazole, quinoline, isoquinoline, indole, isoindole, quinazoline, cinnoline, glucose, quinoxaline, phthalazine, acridine, dodecyl mercaptan, etc. Can be mentioned as a preferred example.

The addition amount of these protective film forming agents is 500 ppm or less, preferably 200 ppm or less, more preferably 100 ppm or less, from the viewpoint of polishing rate and from the viewpoint of manifesting the effect of suppressing dishing.
Including the water-soluble polymer compound and / or the polyhydric alcohol compound in the metal polishing composition of the present invention is preferable from the viewpoint of improving the polishing uniformity of the obtained polished surface. Examples of the water-soluble polymer used in the present invention include ethers such as polyethylene glycol, polypropylene glycol, and polyethylene glycol alkyl ether; vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrolein; polyacrylic acid, polymethacrylic acid, Polycarboxylic acids such as polyacrylamide, polyamic acid and ammonium polyacrylate and their salts; polysaccharides such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, cellulose acetate, cellulose nitrate, cellulose sulfate, pectin, etc. , Starch, albumin and the like are preferable examples. Polyethylene glycol, hydroxyethyl cellulose, hydroxypropyl Pills cellulose, carboxymethyl cellulose, but are mentioned as more preferable examples.

In the present invention, the polyhydric alcohol compound is a low molecular compound other than the above water-soluble polymer compound, and refers to a compound having a plurality of hydroxyl groups in one molecule, such as ethylene glycol, glycerin, propanediol, pentaerythritol, Fructose, sucrose, diethylene glycol, triethylene glycol and the like are listed as preferred examples, and ethylene glycol, glycerin, diethylene glycol and triethylene glycol are listed as more preferred examples.
The content of the water-soluble polymer compound and / or polyhydric alcohol compound used in the polishing composition of the present invention varies depending on the type and the type and amount of the polyoxo acid (salt) to be used, but is preferably 0.00. It is the range of 01-50 mass%, More preferably, it is the range of 0.1-20 mass%. That is, 0.01% by mass or more is preferable from the viewpoint of the effect of addition, and 50% by mass or less is preferable from the viewpoint of increase in viscosity due to addition.

  As described above, the polishing composition of the present invention can perform desired polishing without including abrasive grains that are usually used for the purpose of mechanical polishing, but uses abrasive grains for the purpose of further increasing the polishing rate. It is also possible. Examples of the abrasive grains used here include inorganic particles such as alumina, silica, ceria, zirconia, and magnesium oxide, and organic particles such as organic polymer, amorphous carbon, and carbon black. Among these, colloidal is preferable. Alumina and colloidal silica.

  In the chemical mechanical polishing apparatus used in the present invention, the polishing pad provided has a hole for supplying a metal polishing composition to the surface of the polishing pad, and the chemical mechanical polishing apparatus performs the polishing through the hole of the polishing pad. An apparatus for supplying the metal polishing composition to the pad surface is provided. Furthermore, it is preferable that a device for orbiting the polishing pad is provided.

An example of a preferable chemical mechanical polishing apparatus used in the present invention will be described below.
The polishing pad is connected to a supporting base having means for orbiting or connected to the orbiting device. The carrier is preferably a front reference carrier and holds the semiconductor wafer against the polishing pad while the support base orbits the polishing pad.

  Also, during the polishing process, the carrier can be connected to a motor via a shaft to rotate or otherwise move the semiconductor wafer. Furthermore, it is preferable to use a carrier to which a plurality of different pressure zones can be applied on the back surface of the semiconductor wafer, since further flexibility can be obtained for the planarization process. By adjusting the track radius and / or track speed, the polishing process can be optimized for various semiconductor wafers and thin films deposited on the semiconductor wafer. By orbiting the polishing pad with a smaller orbital radius, or orbiting the polishing pad with a faster orbital velocity, preferably by combining the two, the result of the polishing can be improved.

  The polishing method of the present invention can be carried out by placing a semiconductor wafer in a carrier, preferably a front reference carrier, and placing the semiconductor wafer in proximity to a polishing pad attached to a substantially rigid platen. The semiconductor wafer is polished by pressing the semiconductor wafer against the polishing pad while orbiting the polishing pad, preferably with a radius of less than 4 mm, at a speed exceeding 400 orbits / minute. Also, the carrier can be rotated to smooth and remove patterns that are often formed on the front surface of the semiconductor wafer. Alternatively, the carrier can be rotated alternately in the clockwise and counterclockwise directions, preferably at an angle of less than 360 degrees, to simplify the supply of fluid to the carrier.

  When using a front reference carrier with a plurality of individually controllable pressure zones, a further improvement is obtained for the polishing process. The pressure applied to the semiconductor wafer in contact with the back surface of the semiconductor wafer can be increased or decreased according to the zone where the material to be removed is large or small on the front surface of the semiconductor wafer. The semiconductor wafer polishing process can be terminated by removing the semiconductor wafer from the polishing pad or stopping the relative movement between the semiconductor wafer and the polishing pad.

  With reference to FIG. 2, an example of an apparatus for carrying out the present invention will be described in detail. The front reference carrier 215 can be used to hold the semiconductor wafer 216 and press the semiconductor wafer 216 against the polishing pad 207 during the planarization process. The front reference carrier 215 applies a substantially uniform pressure to the back surface of the semiconductor wafer 216 even when there are protrusions on the back surface of the semiconductor wafer 216. For this reason, the problem relating to the back-reference carrier protrusions, that is, the occurrence of a strong local pressure at the spot on the front surface of the semiconductor wafer opposite to the protrusions, is avoided. The front reference carrier 215 typically applies pressure to the back surface of the semiconductor wafer 216 using a pressurized fluid (eg, filtered air, deionized water, etc.) and / or a flexible membrane / diaphragm 203. Some examples of front reference carriers that can be used to practice the present invention are described, for example, in US Pat. No. 5,423,716 (Strasbaugh), US Pat. No. 5,449,316 (Strasbaugh), US Pat. No. 5,635,083 (Breivogel et al.), US Pat. No. 5,851,140 (Barns et al.), US Pat. No. 6,012,964 (Arai et al.) And US Pat. , 024,630 (Shendon et al.) And the like. The front reference carrier 215 can have a plurality of zones 204, 228, which are usually concentric with each other and can be individually pressurized to produce a plurality of uniform pressure zones. In other words, different pressures are applied to each zone, but the pressure within each zone is substantially uniform.

  A front reference carrier 215 having multiple zones can be suitably used to quickly remove excess material from a concentric zone having a bulge in front of the semiconductor wafer 216. In particular, the front reference carrier 215 having a plurality of zones can apply a higher uniform pressure to the back surface of the semiconductor wafer 216 opposite to the bulge. At the same time, a lower, uniform pressure is applied in other zones on the backside of the semiconductor wafer 216, such as the zone between bulges.

  Examples of multi-zone front reference carriers that can be used to practice the present invention are described, for example, in US Pat. No. 5,941,758 (Mack), US Patent Application No. 09 / 540,476, and US Patent Application. No. 08 / 504,686 and the like. FIG. 2 also shows an example of a front reference carrier 215 having uniform pressure zones 204 and 228 that can be individually controlled. The pressure source 227 can supply pressure to the two pressure regulators 223 and 224 via the manifold 229. The pressure regulators 223 and 224 are preferably computer controlled and can be connected to the control system 230. The pressure regulators 223 and 224 can send pressurized fluid to a corresponding rotary coupler (not shown) in the carrier shaft 201. The rotating coupler can then route pressurized fluid through the tubes or channels 225, 226 in the carrier shaft 201 to the corresponding tubes or channels in the front reference carrier 215. The tubes or channels in the front reference carrier 215 then flow pressurized fluid to the zones 204, 228 in the front reference carrier 215 to control the pressure applied to the corresponding zone on the backside of the semiconductor wafer 216. Zones 204 and 228 are separated by one or more ring-shaped barriers 205 so that each zone can have a separate internal pressure.

  For this reason, the control system 230 can individually control the pressure applied to the two zones 204 and 228 on the back surface of the semiconductor wafer 216. It should be understood that various other carriers can be used to facilitate applying the desired pressure on the backside of the semiconductor wafer 216. Here, the front reference carrier 215 is particularly described in detail, and the present invention is preferably implemented using the front reference carrier, but the present invention can also be implemented using various front reference carriers and back reference carriers. It is.

  The front reference carrier 215 can be held stationary or can perform various movements, for example, linear, orbital, oscillating or rotating on the polishing pad 207. For example, the front reference carrier 215 can be rotated by the motor 222 via the carrier shaft 201. When the front reference carrier 215 rotates, it is desirable to rotate at about 10 to 20 rpm. It has been observed that rotating the front reference carrier 215 smoothes or removes patterns that tend to occur on the front surface of the semiconductor wafer 216 due to the periodicity of the orbital motion of the polishing pad 207. Further, the front reference carrier 215 can be alternately rotated clockwise and counterclockwise.

  This is particularly advantageous and preferred when using a front reference carrier with multiple chambers. Every chamber requires an additional fluid communication path to operate. When the front reference carrier 215 rotates in only one direction, complicated fluid supply means such as a rotary coupling is required. However, when the front reference carrier 215 rotates alternately in the clockwise and counterclockwise directions, and more preferably when it does not rotate up to 360 degrees, a conventional fluid supply means such as a tube can be used.

  During the polishing process, the front surface of the semiconductor wafer 216 is generally pressed against the polishing pad 207 secured to the platen 221 in the presence of slurry. The polishing pad 207 may be, for example, IC1000 / Suba400 or IC1400. Both products are available from Rodel Inc., headquartered in Phoenix, Arizona. Manufactured and provided commercially. The specific polishing pad 207 to be used can be changed according to the characteristics of the semiconductor wafer 216, but is usually made of a urethane-based material. As shown in FIG. 3, the polishing pad 207 includes a hole 322 for supplying slurry to the surface of the polishing pad 207. The polishing pad 207 can also include grooves (not shown) to assist in spreading the slurry across the surface of the polishing pad 207.

Referring back to FIG. 2, the platen 221 can be made from a hard material having a substantially flat surface for mounting the polishing pad 207. The platen 221 of the present invention should be rigid to support the polishing pad. For example, the platen 221 is composed of aluminum, stainless steel, ceramic, titanium or other hard and preferably non-corrosive material.
During the polishing process, the platen 221 can be orbited by the support table 220. The trajectory motion of the polishing pad 207 will be described in detail with reference to FIG. The polishing pad 207 moves to positions 207a, 207b, 207c, and 207d at time 1, time 2, time 3, and time 4, respectively. As a result, “X” on the polishing pad moves while drawing a circle 400a. Note that the polishing pad 207 does not rotate during orbital motion. The orbital radius is the same as the radius of the circle 400a or other circles drawn by one orbital motion point on the polishing pad. The magnitude of the orbital motion indicated by the circle 400a is larger than normally desired in order to facilitate explanation of the orbital movement.

  Referring to FIG. 5, a semiconductor wafer 216 is shown with a plurality of circular motions 400b. Circular motion 400b represents the movement followed by each point on the front surface of semiconductor wafer 216 during orbital motion. The radius of the trajectory that produces the circular motion 400b is significantly smaller than the radius of the trajectory that produces the circular motion 400a. The orbit radius can be controlled by the mechanism used to produce the orbital motion, and some examples are considered here. For example, US Pat. No. 5,582,534 (Shendon) and US Pat. No. 5,938,884 (Hoshizaki et al.) Disclose several mechanisms for producing the orbital motion of a carrier. The principles of these mechanisms disclosed to produce orbital motion can be applied by those skilled in the art to make a support base 220 that can orbit the platen 221.

  FIG. 6 is a cross-sectional view of an exemplary support base 220 that can be used to cause the orbital motion of the platen 211. This support is generally disclosed in US Pat. No. 5,554,064 (Breivogel et al.), Which is hereby incorporated by reference. The support table 220 includes a rigid fixed frame 502 that can be firmly fixed to the ground. The fixed frame 502 is used to support and balance the motion generator. The outer ring 504 of the lower bearing 506 is firmly fixed to the fixed frame 502 by a clamp. The fixed frame 502 prevents the outer ring 504 of the lower bearing 506 from rotating. A wave generator 508 formed by a circular hollow hard stainless steel body is attached to the inner ring 510 of the lower bearing 506. The wave generator 508 is also attached to the outer ring 512 of the upper bearing 514. The wave generator 508 places the upper bearing 514 in parallel with the lower bearing 506. The wave generator 508 offsets the central axis 515 of the upper bearing 514 from the central axis 517 of the lower bearing 506.

  The aluminum circular platen 211 is disposed symmetrically with respect to the inner ring 519 of the upper bearing 514 and is secured thereto. The polishing pad or polishing pad assembly can be secured to a ridge 525 formed around the outer edge of the top surface of the platen 211. A universal joint 518 having two pivot points 520 a and 520 b is firmly fixed to the fixed frame 502 and the lower surface of the platen 211. The lower part of the wave generator 508 is rigidly connected to a hollow and cylindrical drive spool 522 which is then connected to a hollow and cylindrical drive pulley 523. Drive pulley 523 is coupled to motor 526 by belt 524. The motor 526 may be a variable speed three-phase two-horsepower AC motor.

  The orbital motion of the platen 211 is caused by spinning the wave generator 508. The wave generator 508 is rotated by a variable speed motor 526. As the wave generator 508 rotates, the central axis 515 of the upper bearing 514 rotates around the central axis 517 of the lower bearing 506. The track radius of the upper bearing 514 is equal to the offset (R) 526 between the central axis 515 of the upper bearing 514 and the central axis 517 of the lower bearing 506. Upper bearing 514 rotates about central axis 517 of lower bearing 506 at a speed equal to the rotation of wave generator 508. Note that as wave generator 508 rotates, outer ring 512 of upper bearing 514 orbits and rotates (spins) at the same time.

The function of the universal joint 518 is to prevent torque due to rotation or spin of the platen 211. The two pivot points 520a and 520b of the universal joint 518 allow the platen 211 to move in all directions except the rotational direction. By connecting the platen 211 to the inner ring 519 of the upper bearing 514 and connecting the universal joint 518 to the platen 211 and the fixed frame 502, the rotational movement of the inner ring 519 and the platen 211 is prevented, so that the platen 211 is Only orbital motion is performed. The orbital speed of the platen 211 is equal to the rotational speed of the wave generator 508, and the orbital radius of the platen 211 is equal to the offset of the central axis 515 of the upper bearing 514 from the central axis 517 of the lower bearing 506. It should be understood that various other known means can be used to facilitate the orbiting of the polishing pad. Although specific methods for generating orbital motion have been described in detail, the present invention can be implemented using various techniques for orbiting the polishing pad on the platen 211.

  A typical operation method of the chemical mechanical polishing apparatus used in the present invention will be described with reference to FIGS. The first step is to load the semiconductor wafer 216 onto the front reference carrier 215 (step 600). Although a back reference carrier can also be used, in the present invention, good results were obtained when the front reference carrier 215 was used. If the semiconductor wafer 216 has one or more concentric bulges on its front surface, it is appropriate to use a front reference carrier 215 having a plurality of individually controllable pressure zones. The individually controllable pressure zone can apply a higher pressure to the backside of the semiconductor wafer that abuts the bulge than the pressure applied to the recess or low point of the semiconductor wafer. The number and location of bulges can be determined, for example, by taking measurements in situ or knowing the shape of a typical semiconductor wafer produced by a pretreatment process.

Next, the semiconductor wafer 216 is disposed adjacent to the polishing pad 207 fixed to the platen 221 (step 601). Mechanical means for moving the semiconductor wafer 216 to a position proximate the polishing pad 207 are known in the art and will not be mentioned in order to avoid unnecessarily obscuring the present invention.
The semiconductor wafer 216 is pressed against the polishing pad 207 by the pressure applied to the back surface of the semiconductor wafer 216 (step 604). The optimum pressure applied to the backside of the semiconductor wafer 216 can vary depending on the characteristics of the semiconductor wafer 216, the polishing pad 207, the slurry, the desired removal rate, and other factors. However, pressures between about 0.5 psi and about 2 psi produced very good results. However, the present invention can be easily used at lower or higher pressures.

At substantially the same time as the semiconductor wafer 216 is pressed against the polishing pad 207 (step 604), the polishing pad 207 can begin an orbital motion (step 602) and the carrier can begin to rotate (step 603). It is desirable that the polishing pad 207 orbits at a speed exceeding 400 revolutions / minute, and an extremely good flattening is obtained at an orbit radius of 16 mm and an orbital speed of about 600 times / minute. Further, the orbit radius of the polishing pad 207 can be made less than 6 mm, and an extremely good flattening was obtained at an orbital rotation frequency of about 6400 revolutions / minute and an orbital radius of about 1.5 mm. Small trajectory radii generally require a higher trajectory period to maintain a given rate of material removal from the front surface of the semiconductor wafer 216. The front reference carrier 215 can rotate at a speed lower than 30 rpm, and a speed between about 10 and about 20 rpm is desirable. If the front reference carrier 215 rotates alternately without rotating up to 360 degrees clockwise or counterclockwise, the tubes or channels 225 and 226 can be simplified.
The semiconductor wafer 216 can be removed from the polishing pad 207 based on the input from the end point detection system or based on the time required for the specific planarization process determined by experience, and the planarization process can be completed.

Hereinafter, the present invention will be described based on examples.
[Formulation Example 1]
After dissolving 12 g of phosphovanadomolybdic acid (trade name: PVM-1-11, manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) as a polyoxoacid in 187 g of water, dodecylbenzenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as an anionic surfactant After adding 1 g and mixing, water was added and diluted 3 times to obtain a metal polishing composition (A).
[Formulation Example 2]
After dissolving 12 g of phosphovanadomolybdic acid as polyoxo acid in 187 g of water, 0.55 g of dodecylbenzenesulfonic acid and 0.02 g of glycine (manufactured by Wako Pure Chemical Industries, Ltd.) were added and mixed as an anionic surfactant, By adding water and diluting 3 times, a metal polishing composition (I) was obtained.

[Composition Example 3]
After 12 g of phosphovanadotungstic acid (trade name PVW-1-11 manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) was dissolved in 187 g of water as polyoxo acid, 0.5 g of methanesulfonic acid, 0.03 g of histidine as an anionic surfactant, After adding and mixing 0.008 g of quinaldic acid (made by Wako Pure Chemical Industries, Ltd.), water was added and diluted 3 times to obtain a metal polishing composition (U).
[Formulation Example 4]
10 g of silicomolybdic acid (trade name SM manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) as a polyoxo acid was dissolved in 189 g of water, and then 0.4 g of dodecylbenzenesulfonic acid, 0.02 g of histidine, 0.02 g of quinaldic acid as an anionic surfactant. After 01 g was added and mixed, water was added and diluted 3 times to obtain a metal polishing composition (D).

[Formulation Example 5]
After 12 g of phosphomolybdic acid as polyoxo acid was dissolved in 187 g of water, 0.5 g of paratoluenesulfonic acid and 0.02 g of proline (manufactured by Wako Pure Chemical Industries, Ltd.) were added and mixed as an anionic surfactant. Was added and diluted 3 times to obtain a metal polishing composition (e).
[Composition Example 6]
After dissolving 12 g of silicotungstic acid as a polyoxo acid in 187 g of water, 0.5 g of benzenesulfonic acid and 0.02 g of nicotinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) are added and mixed as an anionic surfactant. Was added and diluted 3 times to obtain a metal polishing composition (f).

[Composition Example 7]
After dissolving 12 g of phosphomolybdic acid (trade name: PVW-1-11 manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) in 187 g of water as a polyoxo acid, 0.5 g of methanesulfonic acid, 0.03 g of histidine, quinaldine as an anionic surfactant After adding and mixing 0.008g of acid (made by Wako Pure Chemical Industries, Ltd.), water was added and diluted 3 times to obtain a metal polishing composition (ki).
[Formulation Example 8]
A polishing composition for metal (ku) in which 4 g of phosphovanadmolybdic acid was dissolved in 196 g of water was obtained.

[Formulation Example 9]
A metal polishing composition (ke) was prepared by dissolving 4 g of phosphovanad tungstic acid in 196 g of water.
[Formulation Example 10]
A metal polishing composition (co) in which 4 g of silicomolybdic acid was dissolved in 196 g of water was obtained.
[Formulation Example 11]
A metal polishing composition (sa) in which 1 g of dodecylbenzenesulfonic acid was dissolved in 199 g of water was obtained.
[Composition Example 12]
A polishing composition for metal (si) in which 1 g of methanesulfonic acid was dissolved in 199 g of water was obtained.
[Formulation Example 13]
A polishing composition for metal (su) in which 0.01 g of histidine was dissolved in 200 g of water was obtained.
[Formulation Example 14]
A polishing composition for metal (C) in which 0.01 g of quinaldic acid was dissolved in 200 g of water was obtained.
[Formulation Example 15]
A metal polishing composition (So) was obtained in exactly the same manner as in Formulation Example 5, except that the same amount of lauryltrimethylammonium chloride was used as the cationic surfactant instead of the nonionic surfactant. In addition, sedimentation of the particles was confirmed after leaving this composition for 1 day.

[Example 1]
As a semiconductor wafer, a silicon wafer provided with a copper film on a silicon oxide insulating film having a diameter of 300 mm is used, and the metal polishing composition (a) obtained in Formulation Example 1 is used as an abrasive from the hole of the polishing pad in an amount of 300 ml / min. Supply a pad made of polyurethane resin as a polishing pad, and use a NOVELLUS MOMENTUM300 as a polishing device, carrier rotation speed 20 rpm, polishing pad rotation speed 700 rpm, polishing pad orbit radius 4 mm, applied to the wafer Polishing was performed at a polishing pad pressure of 1.4 psi (100 g / cm ² ) to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 850 nm / min and the dishing was 16 nm.

[Example 2]
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (A) obtained in Formulation Example 2 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 810 nm / min and the dishing was 19 nm.

Example 3
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (C) obtained in Formulation Example 3 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 780 nm / min and the dishing was 19 nm.

Example 4
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (D) obtained in Formulation Example 4 was used as an abrasive to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 765 nm / min and the dishing was 23 nm.

Example 5
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (e) obtained in Formulation Example 5 was used as an abrasive, to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 687 nm / min and the dishing was 22 nm.

Example 6
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (f) obtained in Formulation Example 6 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 697 nm / min and the dishing was 22 nm.

Example 7
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition (ki) obtained in Formulation Example 3 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 735 nm / min and the dishing was 27 nm.

[Comparative Example 1]
Polishing was performed in the same manner as in Example 1 except that the metal polishing composition was supplied not from the hole of the polishing pad but from above the polishing pad to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 430 nm / min and the dishing was 35 nm.

[Comparative Example 2]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (A) obtained in Formulation Example 2 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 503 nm / min and the dishing was 55 nm.

[Comparative Example 3]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (c) obtained in Formulation Example 3 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 551 nm / min and the dishing was 53 nm.

[Comparative Example 4]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (D) obtained in Formulation Example 4 was used as an abrasive to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 487 nm / min and the dishing was 78 nm.

[Comparative Example 5]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (e) obtained in Formulation Example 5 was used as an abrasive to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 509 nm / min and the dishing was 87 nm.

[Comparative Example 6]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (f) obtained in Formulation Example 6 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 501 nm / min and the dishing was 72 nm.

[Comparative Example 7]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (ki) obtained in Formulation Example 7 was used as an abrasive, and a semiconductor wafer having a pattern width of 150 μm was obtained. The polishing rate was 511 nm / min and the dishing was 87 nm.

[Comparative Example 8]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (K) obtained in Formulation Example 8 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 545 nm / min and the dishing was 490 nm.

[Comparative Example 9]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (K) obtained in Formulation Example 9 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 534 nm / min and the dishing was 523 nm.

[Comparative Example 10]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (co) obtained in Formulation Example 10 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 522 nm / min and the dishing was 443 nm.

[Comparative Example 11]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (sa) obtained in Formulation Example 11 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 50 nm / min or less, and dishing could not be measured.

[Comparative Example 12]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (B) obtained in Formulation Example 12 was used as an abrasive, and a semiconductor wafer having a pattern width of 150 μm was obtained. The polishing rate was 50 nm / min or less, and dishing could not be measured.

[Comparative Example 13]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (s) obtained in Formulation Example 13 was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 10 nm / min or less, and dishing could not be measured.

[Comparative Example 14]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (se) obtained in Formulation Example 14 was used as an abrasive, and a semiconductor wafer having a pattern width of 150 μm was obtained. The polishing rate was 10 nm / min or less, and dishing could not be measured.

[Comparative Example 15]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (So) obtained in Formulation Example 15 was used as an abrasive to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 430 nm / min and the dishing was 370 nm.

[Comparative Example 16]
Polishing was performed in the same manner as in Comparative Example 1 except that the metal polishing composition (ta) sold by Company A was used as the polishing agent to obtain a semiconductor wafer having a pattern width of 150 μm. The polishing rate was 180 nm / min and the dishing was 27 nm.

  According to the method for manufacturing a semiconductor wafer of the present invention, it becomes possible to polish a metal film such as a copper film at a high speed even under a low polishing pressure while suppressing etching and dishing, which has been difficult in the prior art. The present invention has found a method for manufacturing a semiconductor wafer that is extremely useful for polishing a metal film formed on a semiconductor wafer, and has a great industrial utility value.

It is a schematic sectional drawing which shows the example of formation of the metal wiring using CMP technique. FIG. 6 is a cross-sectional view of a front reference carrier that holds a semiconductor wafer against a polishing pad attached to a platen. It is a top view of the semiconductor wafer adjacent to the polishing pad which orbits. 1 is a plan view of a stationary semiconductor wafer, shown with orbiting polishing pads at four different times during the orbiting of the polishing pad. FIG. FIG. 2 is a front view of a semiconductor wafer showing the movement experienced at every point on the front side of the semiconductor wafer only by orbital motion. FIG. 6 is a cross-sectional view of one possible mechanism for causing orbital motion of the polishing pad. It is a figure explaining an example of the grinding | polishing method.

Explanation of symbols

(A) Semiconductor wafer (b) Insulating film (c) Barrier metal layer (d) Metal film

Claims (11)

  A chemical mechanical polishing apparatus equipped with a polishing pad is used to form a metal film formed on a semiconductor wafer using a metal polishing composition comprising a polyoxoacid, an anionic surfactant and water. In the method of chemical mechanical polishing by pressing the metal film surface against the polishing pad, the polishing pad comprises a hole for supplying the metal polishing composition to the polishing pad surface, and the chemical mechanical polishing apparatus comprises An apparatus for supplying the metal polishing composition to the surface of the polishing pad through the hole of the polishing pad is provided, and the metal polishing composition is supplied between the metal film and the polishing pad during polishing from the hole. A method for polishing a semiconductor wafer.   The method for polishing a semiconductor wafer according to claim 1, wherein the polyoxoacid is a heteropolyacid.   The chemical mechanical polishing apparatus includes a support base connected to orbit the polishing pad, and a carrier that holds the semiconductor wafer and presses the metal film surface on the semiconductor wafer against the polishing pad. The semiconductor wafer polishing method according to claim 1, wherein the semiconductor wafer is polished.   4. The semiconductor wafer polishing method according to claim 3, wherein the carrier is a front reference carrier.   4. The semiconductor wafer polishing method according to claim 3, wherein the carrier is a back surface reference carrier.   6. The method for polishing a semiconductor wafer according to claim 3, wherein the support pad is moved orbitally with respect to the semiconductor wafer by an orbit radius of less than 4 mm.   The method for polishing a semiconductor wafer according to claim 3, wherein the polishing pad is caused to orbit at a trajectory speed exceeding 400 rpm. Semiconductor wafer polishing method
(A) loading a semiconductor wafer onto a carrier (i) placing the semiconductor wafer close to the polishing pad (iii) pressing the semiconductor wafer against the polishing pad (e) orbiting the polishing pad The semiconductor wafer according to any one of claims 1 to 7, comprising a step of moving and a step of removing the semiconductor wafer from the polishing pad in the order of (a) to (o). Polishing method. The semiconductor wafer polishing method comprises:
9. The method for polishing a semiconductor wafer according to claim 8, further comprising the step of rotating the semiconductor wafer before removing the semiconductor wafer from the polishing pad. The semiconductor wafer polishing method comprises:
9. The method for polishing a semiconductor wafer according to claim 8, further comprising a step of alternately rotating the semiconductor wafer clockwise and counterclockwise before removing the semiconductor wafer from the polishing pad.   In the polishing method of the semiconductor wafer, the step (ii) applies a first pressure to a central zone on the back surface of the semiconductor wafer, and the first pressure is applied to a peripheral zone concentric with the central zone. The method for polishing a semiconductor wafer according to claim 8, further comprising applying a different second pressure.

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