A method for manufacturing a polishing slurry and a semiconductor device

Abstract

To provide polishing slurry and a method of manufacturing a semiconductor device.SOLUTION: Polishing slurry includes a fullerene derivative and a compound having at least one positively charged functional group. Also provided is a method of manufacturing a semiconductor device using the polishing slurry.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polishing slurry and a method for manufacturing a semiconductor device.

Background Art

[0002] Recently, due to the miniaturization of electronic devices and the accompanying miniaturization of integrated circuits, various methods for forming fine structures such as metal wiring with a width of several nanometers or shallow trench isolation have been studied.

[0003] At the stage of forming such fine structures, a polishing process is performed to create a flat surface of the fine structure. One of the polishing processes is chemical mechanical polishing (CMP). Chemical mechanical polishing is a process in which a polishing slurry containing an abrasive is provided between a semiconductor substrate on which the polishing process is performed and a polishing pad, and then the semiconductor substrate is brought into contact with the polishing pad to flatten the surface of the substrate.

[0004] A polishing slurry containing existing polishing particles with a particle size of several tens of nanometers such as silica used for forming fine structures may cause damage and morphological deformation of fine pitch structures.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One embodiment of the present invention provides a polishing slurry capable of improving polishing performance while reducing damage and morphological deformation of a structure.

[0006] Another embodiment of the present invention provides a method for manufacturing a semiconductor device using the polishing slurry.

[0007] According to one embodiment of the present invention, there is provided a polishing slurry containing a fullerene derivative and a compound having at least one positively charged functional group.

Means for Solving the Problem

[0008] The fullerene derivative can have at least one negatively charged functional group. The negatively charged functional group can include at least one selected from a hydroxy group, a carbonyl group, a carboxylate group, a sulfonic acid group, a sulfate group, a sulfhydryl group, and a phosphate group.

[0009] The fullerene derivative is represented by the following Chemical Formula 1. [Chemical Formula 1] C x (OH) y (Here, x is 60, 70, 74, 76 or 78, and y is 12 to 44.)

[0010] The average particle diameter of the fullerene derivative can be less than 10 nm. The compound having at least one positively charged functional group can have a LUMO energy level of 4.3 eV or more and 5.3 eV or less. The positively charged functional group can include a nitrogen-containing functional group.

[0011] The nitrogen-containing functional group can include at least one of an amino group, a nitro group, a secondary amine group, a tertiary amine group, a quaternary ammonium group, a diamine group, a polyamine group, an azo group, an amide group, and a nitrogen-containing heterocyclic group.

[0012] The compound having the positively charged functional group further includes an oxygen-containing functional group, and the atomic ratio of nitrogen (N) to oxygen (O) contained in the compound having the positively charged functional group can be 0.25 or more.

[0013] The oxygen-containing functional group can include at least one of a hydroxy group, an ester group, a carbonyl group, and a carboxylic acid group. The compound having the positively charged functional group can have at least two positively charged functional groups.

[0014] Examples of the compound having a positively charged functional group include at least one of leucine, lysine, methionine, valine, serine, cysteine, cystine, arginine, asparagine, aspartic acid, alanine, ornithine, isoleucine, threonine, tyrosine, glutamine, glutamic acid, glycine, histidine, phenylalanine, proline, urea, or betaine.

[0015] The compound having a positively charged functional group can include a first compound containing one positively charged functional group and a second compound containing two or more positively charged functional groups.

[0016] The first compound can include at least one of leucine, methionine, valine, serine, cysteine, aspartic acid, alanine, isoleucine, threonine, tyrosine, glutamic acid, glycine, phenylalanine, proline, or betaine, and the second compound can include at least one of lysine, cystine, arginine, asparagine, ornithine, glutamine, histidine, or urea.

[0017] The first compound and the second compound can be included in a weight ratio of about 1:3 to 10:1. The compound having a positively charged functional group can have a positive charge in water.

[0018] The fullerene derivative is included in the polishing slurry at 0.001% to 5% by weight, and the compound having a positively charged functional group is included in the polishing slurry at 0.001% to 1% by weight.

[0019] The pH of the polishing slurry can be 1.0 to 7.0. The polishing slurry can further include an oxidizing agent, a chelating agent, a surfactant, a dispersant, an acidity regulator, a solvent, or a combination thereof.

[0020] According to another embodiment of the present invention, there is provided a method for manufacturing a semiconductor device, including the steps of disposing a semiconductor substrate to face a polishing pad, supplying the polishing slurry between the semiconductor substrate and the polishing pad, and performing polishing by bringing the surface of the semiconductor substrate into contact with the polishing pad.

[0021] The polishing slurry can polish metal wiring in the semiconductor substrate. The metal wiring can contain tungsten.

[0022] The ratio of the polishing rate of tungsten to the etching rate of tungsten can be 2 or more.

[0023] The polishing performance can be improved while reducing damage and morphological deformation of the fine pitch structure.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field can easily implement them. However, the actually applied structure is embodied in various different forms and is not limited to the embodiments described here.

[0026] In the drawings, the thicknesses are exaggerated to clearly show various layers and regions. Throughout the specification, like reference numerals have been used for like components. When a part such as a layer, film, region, plate, etc. is "on" another part, this includes not only the case where it is directly "on" the other part, but also the case where there are other parts in between. Conversely, when a part is "directly on" another part, it means that there are no other parts in between.

[0027] Hereinafter, a polishing slurry according to an embodiment of the present invention will be described. A polishing slurry according to an embodiment of the present invention can include a fullerene derivative and a compound having at least one positively charged functional group.

[0028] The fullerene derivative can have a fullerene core and at least one functional group bonded to the fullerene core. The fullerene core can generally be hydrophobic, for example, C 60 、C 70 、C 74 、C 76 or C 78 but is not limited thereto.

[0029] The functional group bonded to the fullerene core can be, for example, a negatively charged functional group, and can include at least one selected from, for example, a hydroxy group, a carbonyl group, a carboxylate group, a sulfonic acid group, a sulfate group, a sulfhydryl group, and a phosphate group, but is not limited thereto. As an example, the negatively charged functional group can be a hydroxy group. The negatively charged functional group means a functional group having a local negative charge or a functional group having an unshared electron pair on oxygen. The fullerene derivative can be a hydrophilic fullerene.

[0030] Fullerene derivatives may have, per fullerene core, an average of one or more negatively charged functional groups bonded thereto. For example, they may have an average of one or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of two or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of three or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of five or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of eight or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of ten or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of twelve or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of sixteen or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of twenty or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of twenty-four or more and less than 44 negatively charged functional groups bonded thereto. For example, they may have an average of twenty-four to forty negatively charged functional groups bonded thereto. For example, they may have an average of twenty-four to thirty-six negatively charged functional groups bonded thereto. For example, they may have an average of twenty-eight to forty-four negatively charged functional groups bonded thereto. For example, they may have an average of twenty-eight to forty negatively charged functional groups bonded thereto. For example, they may have an average of thirty to thirty-eight negatively charged functional groups bonded thereto. For example, they may have an average of thirty to thirty-four negatively charged functional groups bonded thereto.

[0031] Here, the average number of negatively charged functional groups of the negatively charged fullerene can be confirmed by methods such as elemental analysis, thermogravimetric analysis, spectroscopic analysis, and mass spectrometry. For example, it can be the average value of the two highest peaks in liquid chromatography mass spectrometry (LC-MS).

[0032] As an example, the fullerene derivative may be a hydroxyl fullerene represented by the following Chemical Formula 1. [Chemical Formula 1] C x (OH) y (where x is 60, 70, 74, 76 or 78, and y is 2 to 44.)

[0033] Here, the average number of hydroxy groups of the hydroxyl fullerene can be confirmed by methods such as elemental analysis, thermogravimetric analysis, spectroscopic analysis, and mass spectrometry. For example, it can be the average value of the two highest peaks in liquid chromatography mass spectrometry (LC-MS).

[0034] As an example, the fullerene derivative is C x (OH) y (where x is 60, 70, 74, 76 or 78, and y is 12 to 44), and can be a hydroxylated fullerene represented thereby.

[0035] As an example, the fullerene derivative is C x (OH) y (where x is 60, 70, 74, 76 or 78, and y is 24 to 44), and can be a hydroxylated fullerene represented thereby.

[0036] As an example, the fullerene derivative is C x (OH) y (where x is 60, 70, 74, 76 or 78, and y is 32 to 44), and can be a hydroxylated fullerene represented thereby and can carry a negative charge in water.

[0037] The fullerene derivative can effectively act as an abrasive in a polishing slurry, and different from existing abrasives with particle sizes in the tens to hundreds of nanometers such as silica, by having a very small particle size of less than about 10 nm, it can be effectively applied to a fine pitch structure with a width of about 10 nm or less.

[0038] In addition, the negatively charged functional group bonded to the fullerene core can further impart chemical polishing characteristics, and can reduce damage and morphological deformation such as scratch, dishing and / or erosion to the structure to be polished.

[0039] As an example, the fullerene derivative can be fine particles having an average particle diameter of less than about 10 nm, and within the above range, it can have an average particle diameter of less than about 8 nm, less than about 7 nm, less than about 5 nm, for example less than about 3 nm, for example less than about 2 nm or for example less than about 1 nm, and for example it can have an average particle diameter of not less than about 0.01 nm and less than 10 nm, for example not less than about 0.01 nm and less than 8 nm, for example not less than about 0.01 nm and less than 7 nm, for example not less than about 0.01 nm and less than 5 nm, for example not less than about 0.01 nm and less than 3 nm, for example not less than about 0.01 nm and less than 2 nm or for example not less than about 0.01 nm and less than 1 nm. The average particle diameter of the fullerene derivative is measured using MADLS (multi-angle dynamic light scattering).

[0040] The fullerene derivative can be contained in an amount of about 0.001% by weight to 5% by weight based on the total content (including the solvent) of the polishing slurry. Within the above range, the fullerene derivative can be contained in an amount of about 0.001% by weight to 3% by weight, about 0.001% by weight to 2% by weight, about 0.001% by weight to 1% by weight, about 0.001% by weight to 0.8% by weight or about 0.001% by weight to 0.5% by weight.

[0041] The compound having a positively charged functional group can contain at least one positively charged functional group in the molecule. The compound having a positively charged functional group can have, for example, at least 2 positively charged functional groups, can have, for example, at least 3 positively charged functional groups, can have, for example, at least 4 positively charged functional groups, but is not limited thereto. The compound having a positively charged functional group can have, for example, 1 to 7 positively charged functional groups, and within the above range, can have, for example, 2 to 7, 3 to 7 or 4 or 7 positively charged functional groups.

[0042] As an example, the difference between the lowest unoccupied molecular orbital (LUMO) energy level of a compound having a positively charged functional group and the work function of the metal to be polished may be small. For example, the difference between the LUMO energy level of a compound having a positively charged functional group and the work function of the metal to be polished can be about 1.0 eV or less, within the above range, it can be about 0.9 eV or less, about 0.8 eV or less, about 0.7 eV or less, about 0.6 eV or less, about 0.5 eV or less, about 0.4 eV or less, about 0.3 eV or less, about 0.2 eV or less, for example, about 0.1 eV or more and 1.0 eV or less, about 0.1 eV or more and 0.9 eV or less, about 0.1 eV or more and 0.8 eV or less, about 0.1 eV or more and 0.7 eV or less, about 0.1 eV or more and 0.6 eV or less, about 0.1 eV or more and 0.5 eV or less, 0.1 eV or more and 0.4 eV or less, about 0.1 eV or more and 0.3 eV or less, about 0.1 eV or more and 0.2 eV or less.

[0043] As an example, the LUMO energy level of a compound having a positively charged functional group can be about 5.3 eV or less, within the above range, it can be about 5.2 eV or less, about 5.1 eV or less, about 5.0 eV or less, about 4.9 eV or less, about 4.8 eV or less, about 4.7 eV or less, about 4.6 eV or less, about 4.5 eV or less, about 4.4 eV or less, for example, 4.3 eV or more and 5.3 eV or less, 4.3 eV or more and 5.2 eV or less, 4.3 eV or more and 5.1 eV or less, 4.3 eV or more and 5.0 eV or less, 4.4 eV or more and 5.0 eV or less, 4.5 eV or more and 5.0 eV or less, 4.5 eV or more and 4.9 eV or less, 4.5 eV or more and 4.8 eV or less, 4.6 eV or more and 4.8 eV or less.

[0044] Although not wishing to be bound by a particular theory, compounds having a positively charged functional group with such a LUMO energy level have a small energy difference from the work function of a metal to be polished, such as tungsten or copper. Therefore, electrons generated during a polishing process, for example, during the oxidation process of the metal to be polished, can easily move to the compound having a positively charged functional group. Thus, it can be understood that the energy barrier for the movement of electrons generated from the metal to be polished becomes low and the electron mobility is improved, resulting in easy formation of an oxide of the metal to be polished and an increase in the material removal rate (MRR) of the metal to be polished.

[0045] As an example, the positively charged functional group can include a nitrogen-containing functional group. For example, it can include at least one of an amino group, a nitro group, a secondary amine group, a tertiary amine group, a quaternary ammonium group, a diamine group, a polyamine group, an azo group, an amide group, and a nitrogen-containing heterocyclic group, but is not limited thereto. As an example, the nitrogen-containing functional group can be an amino group. For example, the compound having a positively charged functional group can be a compound that is positively charged in water.

[0046] As an example, the compound having a positively charged functional group can further include an oxygen-containing functional group in the compound. For example, it can include at least one of a hydroxy group, an ester group, a carbonyl group, and a carboxylic acid group, but is not limited thereto.

[0047] As an example, the atomic ratio of nitrogen (N) to oxygen (O) in a compound having a positively charged functional group can be about 0.25 or more, and within the above range, it can be about 0.3 or more, about 0.4 or more, about 0.5 or more, about 0.6 or more, about 0.67 or more, about 0.7 or more, about 0.8 or more, about 0.9 or more, about 1.0 or more, about 1.2 or more, about 1.5 or more, about 2.0 or more, about 2.5 or more. For example, it can be about 0.25 or more and 2.5 or less, about 0.3 or more and 2.0 or less, about 0.5 or more and 2.0 or less, about 0.6 or more and 2.0 or less, about 1.0 or more and 2.0 or less, about 1.5 or more and 2.0 or less. Generally, the higher the atomic ratio of nitrogen (N) to oxygen (O) contained in the compound, the more likely it is to preferentially adsorb onto the surface of a metal such as tungsten with a negative surface charge due to electrostatic attraction when polishing the metal, and the effect of reducing or preventing over-etching of the metal surface can be improved.

[0048] As an example, compounds having a positively charged functional group can include at least one of leucine, lysine, methionine, valine, serine, cysteine, cystine, arginine, asparagine, aspartic acid, alanine, ornithine, isoleucine, threonine, tyrosine, glutamine, glutamic acid, glycine, histidine, phenylalanine, proline, urea, betaine, or derivatives thereof, but are not limited thereto. For example, lysine can be L-lysine, D-lysine, or DL-lysine, and arginine can be L-arginine, D-arginine, or DL-arginine, but are not limited thereto.

[0049] Compounds having a positively charged functional group can exhibit positive charge properties in water. As a result, compounds having a positively charged functional group can exhibit charge properties with opposite signs to those of a fullerene derivative having a negatively charged property in water. Therefore, when polishing a metal such as tungsten generally having a negative surface charge, a compound having a positively charged functional group can be preferentially adsorbed onto the surface of the metal rather than the fullerene derivative due to electrostatic attraction.

[0050] The compound having a positively charged functional group preferentially adsorbed onto the surface of the metal can serve as a reaction inhibitor that reduces or prevents over-etching of the metal surface due to an undesired chemical reaction during and / or after the chemical mechanical polishing process.

[0051] For example, during a polishing process using a fullerene derivative, over-etching generated because the etching rate of the metal to be polished is faster than the polishing rate by the fullerene derivative which is a fine polishing particle can be prevented. For example, after the polishing process, excessive etching of the metal surface due to an undesired continuous chemical reaction of fine polishing particles such as a fullerene derivative can be prevented.

[0052] Therefore, by including a compound having a positively charged functional group in the polishing slurry, the etching rate of metal wiring or the like can be decreased in the polishing slurry process. The etching rate is a measure indicating the degree of chemical conversion of the polishing slurry, and the faster the etching rate, the faster the etching of the related metal surface can be indicated.

[0053] As an example, the polishing slurry can contain two or more compounds having a positively charged functional group. For example, it can contain two or more compounds having different numbers of positively charged functional groups. For example, it can contain a first compound containing one positively charged functional group and a second compound containing two or more positively charged functional groups.

[0054] As the first compound, it can contain at least one of leucine, methionine, valine, serine, cysteine, aspartic acid, alanine, isoleucine, threonine, tyrosine, glutamic acid, glycine, phenylalanine, proline, betaine, or derivatives thereof, but is not limited thereto.

[0055] As the second compound, it can contain at least one of lysine, cystine, asparagine, ornithine, glutamine, histidine, urea, or derivatives thereof, but is not limited thereto.

[0056] As an example, the first compound and the second compound can be contained in a weight ratio of, for example, about 1:3 to 10:1, and within the above range, about 1:3 to 9:1, or about 1:3 to 8:1, or about 1:3 to 7:1, or about 1:3 to 5:1, or about 1:3 to 3:1, or about 1:1 to 10:1, or about 1:1.2 to 10:1, or about 1:1.4 to 10:1, or about 1:1.6 to 10:1, or about 1:1.8 to 10:1, or about 1:2 to 10:1.

[0057] The compound having a positively charged functional group can be contained in an amount of about 0.001 wt% to 1 wt% based on the total content (including the solvent) of the polishing slurry. Within the above range, the compound having a positively charged functional group can be contained in an amount of 0.001 wt% to 0.8 wt%, about 0.001 wt% to 0.6 wt%, about 0.001 wt% to 0.4 wt%, about 0.001 wt% to 0.2 wt%, about 0.001 wt% to 0.1 wt% or about 0.001 wt% to 0.05 wt%.

[0058] The pH of the polishing slurry can be achieved or maintained by any suitable means in consideration of any polishing rate, dispersion stability, etc. As an example, the pH of the polishing slurry can be, for example, about 1.0 to 7.0, and within the above range, about 1.0 to 5.0, or about 1.0 to 4.0, or about 1.0 to 3.0, or about 1.0 to 2.5, or about 1.2 to 2.5, or about 1.5 to 2.5, or about 1.5 to 2.0, or about 1.5 to 1.8.

[0059] The polishing slurry can further contain additives, and the additives can further include, for example, oxidizing agents, chelating agents, surfactants, dispersants, acidity regulators, solvents, or combinations thereof, but are not limited thereto.

[0060] The oxidizing agent can be added to the polishing composition during the manufacturing process of the polishing slurry or immediately before the polishing process. For example, it can be hydrogen peroxide solution, periodic acid, potassium iodide, potassium permanganate, ammonium sulfate, ammonium molybdate, iron nitrate, nitric acid, potassium nitrate, sodium hydroxide, potassium hydroxide, or combinations thereof, but is not limited thereto.

[0061] The oxidizing agent can be contained in an amount of about 0.1 wt% to 10 wt% based on the total content (including the solvent) of the polishing slurry. Within the above range, the oxidizing agent can be contained in an amount of 0.1 wt% to 8 wt%, about 0.1 wt% to 6 wt%, about 0.1 wt% to 4 wt%, about 0.1 wt% to 3 wt%, about 0.1 wt% to 2 wt%, or about 0.1 wt% to 1 wt%.

[0062] The chelating agent can be, for example, phosphoric acid, nitric acid, citric acid, malonic acid, salts thereof, or combinations thereof, but is not limited thereto.

[0063] The chelating agent can be contained in an amount of about 0.002 wt% to 20 wt% based on the total content (including the solvent) of the polishing slurry. Within the above range, the chelating agent can be contained in an amount of 0.002 wt% to 10 wt%, about 0.002 wt% to 5 wt%, about 0.002 wt% to 1 wt%, about 0.002 wt% to 0.5 wt%, about 0.002 wt% to 0.1 wt%, about 0.002 wt% to 0.07 wt%, about 0.002 wt% to 0.04 wt%, or about 0.002 wt% to 0.02 wt%.

[0064] The surfactant can be an ionic or non-ionic surfactant. For example, it can be a copolymer of ethylene oxide, a copolymer of propylene oxide, an amine compound, or combinations thereof, but is not limited thereto.

[0065] The dispersant can promote the dispersion of carbon abrasive particles and can include, for example, water-soluble monomers, water-soluble oligomers, water-soluble polymers, metal salts, or combinations thereof. The weight average molecular weight of the water-soluble polymer can be, for example, about 10,000 or less, for example, about 5,000 or less, for example, about 3,000 or less. The metal salt can be, for example, a copper salt, nickel salt, cobalt salt, manganese salt, tantalum salt, ruthenium salt, or combinations thereof. The dispersant can be selected from, for example, poly(meth)acrylic acid, poly(meth)acrylic maleic acid, polyacrylonitrile-co-butadiene-acrylic acid, carboxylic acid, sulfonic acid ester, sulfonic acid, phosphoric acid ester, cellulose, diol, salts thereof, or combinations thereof, but is not limited thereto.

[0066] The pH adjuster can adjust the pH of the polishing slurry and can be, for example, an inorganic acid, an organic acid, salts thereof, or combinations thereof. The inorganic acid can include, for example, nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, or salts thereof, and the organic acid can include, for example, formic acid, malonic acid, maleic acid, oxalic acid, adipic acid, citric acid, acetic acid, propionic acid, fumaric acid, lactic acid, salicylic acid, benzoic acid, succinic acid, phthalic acid, butyric acid, glycolic acid, malic acid, tartaric acid, or salts thereof, but is not limited thereto.

[0067] Each additive can be independently included in a trace amount, for example, about 1 ppm to 100,000 ppm, but is not limited thereto.

[0068] The polishing slurry can further include a solvent capable of dissolving or dispersing the above-described components. The solvent can be, for example, a polar solvent and can be, for example, water, alcohol, acetic acid, acetone, or a mixture thereof. As an example, the solvent can be water and can be, for example, distilled water, deionized water, ion-exchanged water, and / or ultrapure water.

[0069] The above-described polishing slurry can be applied during the formation of various structures, for example, it can be applied to the polishing process of conductors such as metal wiring or to the polishing process of insulators such as shallow trench isolation (STI) or insulating films. As an example, the polishing slurry can be used to polish a conductive layer, an insulating layer, and / or a semiconductor layer having a charged surface in a semiconductor substrate. For example, it can be effectively used to polish a conductive layer, an insulating layer, and / or a semiconductor layer generally having a negatively charged surface.

[0070] As an example, the polishing slurry can be used to polish conductors such as metal wiring in a semiconductor substrate, for example, it can be used to polish conductors such as copper (Cu), tungsten (W), or alloys thereof.

[0071] Hereinafter, an example of a method for manufacturing a semiconductor device using the above-described polishing slurry will be described. FIGS. 1 to 4 are cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

[0072] Referring to FIG. 1, an interlayer insulating film 20 is formed on a semiconductor substrate 10. The interlayer insulating film 20 can include an oxide, a nitride, and / or an oxynitride. Next, the interlayer insulating film 20 is etched to form a trench 20a. The trench 20a can have a width of about 10 nm or less. Then, a barrier layer 30 is formed on the wall surface of the trench. The barrier layer 30 can include, for example, Ta and / or TaN, but is not limited thereto.

[0073] Referring to FIG. 2, a metal such as copper (Cu) is embedded inside the trench to form a metal layer 40.

[0074] Referring to FIG. 3, a planarized and embedded metal layer 40a is formed such that the surface of the metal layer 40 coincides with the surface of the interlayer insulating film 20. The planarization can be performed by chemical mechanical polishing (CMP) using a CMP apparatus, and the above-described polishing slurry can be used. This will be described later. As an example, when the barrier layer 30 is a Ta layer and the metal layer 40 is a Cu layer, the higher the polishing selectivity of the Ta with respect to the Cu in the polishing slurry, the more preferable it is, for example, preferably higher than about 50:1.

[0075] Referring to FIG. 4, a capping layer 50 is formed on the embedded metal layer 40 and the interlayer insulating film 20. The capping layer 50 can include, but is not limited to, SiN and / or SiC.

[0076] Hereinafter, the planarization step for forming the embedded metal layer 40a will be described. The planarization step can be performed by chemical mechanical polishing using a CMP apparatus as described above.

[0077] The chemical mechanical polishing apparatus can include, for example, a lower base; a platen rotatably provided on the upper surface of the lower base; a polishing pad disposed on the platen; a pad conditioner; and at least one polishing slurry supply device disposed adjacent to the polishing pad for supplying the polishing slurry to the polishing pad.

[0078] The platen can be rotatably provided on the surface of the lower base. For example, the platen can receive rotational power from a motor disposed within the lower base. Thereby, the platen can rotate about a virtual rotation axis perpendicular to the surface of the platen. The virtual rotation axis can be perpendicular to the surface of the lower base.

[0079] The platen may be provided with one or more supply lines through which a liquid can be injected and discharged. Water is injected into and discharged from inside the platen through the supply lines, and the temperature of the platen can be adjusted by the injected water. For example, cooling water is injected into and discharged from inside the platen through the supply lines, whereby the temperature of the overheated platen can be lowered. For example, hot water is injected into and discharged from inside the platen through the supply lines, whereby an increase in the temperature of the platen can be induced.

[0080] The polishing pad is disposed on the surface of the platen so as to be supported by the platen. The polishing pad can rotate together with the platen. The polishing pad can have a coarsely formed polishing surface. Such a polishing surface can mechanically polish the surface of the semiconductor substrate 10 in direct contact with the semiconductor substrate 10. The polishing pad is made of a porous material having a large number of micro spaces, and the large number of micro spaces can accommodate a polishing slurry.

[0081] The pad conditioner is disposed adjacent to the polishing pad and can maintain the state of the polishing surface so that the surface of the semiconductor substrate 10 can be effectively polished during the polishing process.

[0082] The polishing slurry supply device is disposed adjacent to the polishing pad and can supply the polishing slurry to the polishing pad. The polishing slurry supply device can include a nozzle that can supply the polishing slurry onto the polishing pad during the polishing process, and a voltage supply unit that can apply a predetermined voltage to the nozzle. The polishing slurry in the nozzle can be charged by the voltage applied from the voltage supply unit and ejected toward the polishing pad. The polishing slurry supply device can supply the above-described polishing slurry.

[0083] Chemical mechanical polishing is performed, for example, by arranging the semiconductor substrate 10 and the polishing pad to face each other, supplying the above-described polishing slurry from a polishing slurry supply device between the semiconductor substrate 10 and the polishing pad, and performing polishing by bringing the surface of the semiconductor substrate 10 into contact with the polishing pad.

[0084] As an example, the polishing slurry can be used to polish conductors such as metal wirings in the semiconductor substrate, and can be used to polish conductors such as copper (Cu), tungsten (W), or alloys thereof, but is not limited thereto.

[0085] As an example, the step of supplying the polishing slurry can be performed at a rate of, for example, about 10 ml / min to 100 ml / min, and can be supplied at a flow rate of, for example, about 2 μl to 10 μl.

[0086] The polishing step can be performed by mechanical friction by bringing the surface of the semiconductor substrate 10 into contact with the polishing pad and rotating it. For example, a pressure of about 1 psi to 5 psi is applied in the polishing step.

[0087] As an example, when the metal layer 40 and the embedded metal layer 40a contain tungsten, the ratio of the polishing rate (material removal rate, MRR) of tungsten to the etching rate (ER) of tungsten by the polishing slurry is preferably higher, for example, about 1 or more, about 2 or more, about 3 or more, about 4 or more, about 5 or more, about 6 or more, about 7 or more, about 8 or more, about 9 or more, about 10 or more, about 11 or more, about 12 or more, about 13 or more, about 14 or more, about 15 or more, about 16 or more, about 17 or more, about 18 or more, about 19 or more, about 20 or more, and can be about 1 to 20, about 2 to 20, about 3 to 20, about 3 to 19, about 3 to 18, about 3 to 17 within the above range.

[0088] By having such a ratio of the polishing rate to the etching rate, the etching rate of the metal wiring is decreased, thereby ensuring the flatness of the semiconductor substrate after the polishing process and solving problems such as recesses.

[0089] Hereinafter, the above-described embodiments will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights of the present invention.

[0090] Synthesis Example: Synthesis of Fullerene Hydroxide A container (vessel) for a bead mill with a height of about 100 mm and a diameter of about 50 mm was filled with beads to about 1 / 3 of its volume, and 1 g of fullerene (C 60 )(Nanom purple ST, manufactured by Frontier Carbon), 0.5 g / L of a dispersant (polyacrylic acid, Mw 1800, manufactured by Merck), and 100 g of water were added. The beads included 50 g of zirconia beads with an average particle size of 500 μm, 50 g of zirconia beads with an average particle size of 5 mm, and 50 g of zirconia beads with an average particle size of 10 mm.

[0091] Next, after rotating the container for 40 hours, a sample was taken out and its particle size was measured. The particle size was measured using a Zeta-Potential&Particle Size Analyzer ELS-Z (manufactured by Ohkura Electronics Co., Ltd.), which is a dynamic light scattering type particle size distribution meter.

[0092] Next, after confirming that the particle size of the sample became 100 nm or less, 100 g of 30 wt% hydrogen peroxide solution was added thereto to remove the beads. Then, the sample was stirred at about 70 °C for 8 days to produce a fullerene hydroxide dispersion.

[0093] The particle size of the fullerene hydroxide was measured using a dynamic light scattering type particle size distribution meter (Zeta-Potential&Particle Size Analyzer ELS-Z).

[0094] The average number of hydroxyl groups in hydroxylated fullerene was evaluated by Fourier transform infrared spectroscopy (FTIR) and was calculated from the average value of two of the highest peaks in the mass spectrum of hydroxylated fullerene.

[0095] As a result, the average particle size was 2.5 nm and the average number of hydroxyl groups was 36. 60 (OH) 36 It was confirmed that a hydroxide fullerene represented by the formula:

[0096] Manufacturing Example Manufacturing Example 1 C obtained in the synthesis example 60 (OH) 36 0.1% by weight of hydroxide fullerene, 2.4% by weight of hydrogen peroxide, 0.04% by weight of malic acid, 0.0031% by weight of iron nitrate, and 0.1% by weight of L-arginine (N / O=2.0) were mixed in water, and nitric acid was added to adjust the pH to 1.8 to produce 100g of polishing slurry. Here, LUMO is a value measured using ultraviolet photoelectron spectroscopy (XPS, Quantum2000, manufactured by PHI), and N / O is the atomic ratio of nitrogen (N) to oxygen (O) contained in the compound.

[0097] Manufacturing Example 2 A polishing slurry was produced in the same manner as in Production Example 1, except that 0.2% by weight of hydroxide fullerene was used instead of 0.1% by weight of hydroxide fullerene.

[0098] Production Example 3 A polishing slurry was produced in the same manner as in Production Example 1, except that 0.02 wt % of hydroxide fullerene was used instead of 0.1 wt % of hydroxide fullerene, and 0.03 wt % of L-arginine was used.

[0099] Production Example 4 A polishing slurry was produced in the same manner as in Production Example 1, except that 0.02% by weight of hydroxylated fullerene was used instead of 0.1% by weight of hydroxylated fullerene.

[0100] Production Example 5 A polishing slurry was produced in the same manner as in Production Example 1, except that 0.02% by weight of fullerene hydroxide was used instead of 0.1% by weight of fullerene hydroxide, and a mixture of glycine (LUMO: 4.83 eV, N / O = 0.5) and L-arginine at a weight ratio of 7:1 was used to make 0.1% by weight instead of 0.1% by weight of L-arginine.

[0101] Production Example 6 A polishing slurry was produced in the same manner as in Production Example 5, except that lysine (LUMO: 4.93 eV, N / O = 1.0) was used instead of L-arginine.

[0102] Production Example 7 A polishing slurry was produced in the same manner as in Production Example 5, except that a mixture of glycine and glutamine (LUMO: 4.90 eV, N / O = 0.67) at a weight ratio of 1:1.4 was used to make 0.1% by weight instead of the mixture of glycine and L-arginine.

[0103] Production Example 8 A polishing slurry was produced in the same manner as in Production Example 7, except that glutamic acid (LUMO: 4.48 eV, N / O = 0.25) was used instead of glutamine.

[0104] Production Example 9 A polishing slurry was produced in the same manner as in Production Example 1, except that lysine was used instead of L-arginine.

[0105] Production Example 10 A polishing slurry was produced in the same manner as in Production Example 1, except that cysteine (LUMO: 5.23 eV, N / O = 0.5) was used instead of L-arginine.

[0106] Production Example 11 A polishing slurry was produced in the same manner as in Production Example 1, except that glycine was used instead of L-arginine.

[0107] Comparative Production Example 1 A polishing slurry was produced in the same manner as in Production Example 1, except that it did not contain L-arginine.

[0108] Evaluation I The polishing rate (MRR: Material Removal Rate) and the etching rate (ER: Etch Rate) were evaluated by polishing under the following conditions. Polishing apparatus: MA-200e (manufactured by Musashino Denshi) Workpiece to be polished: (1) Wafer for measuring the polishing rate: Prepare a 20 mm × 20 mm wafer with a 1.5 μm thick tungsten (W) film formed on a silicon substrate. (2) Specimen for measuring the etching rate: Prepare a 20 mm × 20 mm tungsten (work function: 4.63 eV) pattern specimen. This specimen is composed of tungsten lines with a width of 0.20 μm and silicon oxide spacer lines with a width of 0.20 μm between the tungsten lines. (3) Polishing pad: IC1000 (manufactured by KPX) (4) Rotation speed of the polishing platen: 90 rpm (5) Rotation speed of the polishing pad: 90 rpm (6) Polishing liquid supply method: Place 200 ml of the polishing slurry on the polishing pad and perform polishing. (7) Polishing pressure: 14 kPa (8) Polishing temperature: 25 °C

[0109] For the polishing rate, polishing was carried out for 5 minutes, and the thickness of the tungsten (W) film before and after polishing was obtained by conversion from the electrical resistance value, and calculated by the speed conversion method. For the etching rate, after the above polishing, the changed weight of the specimen was measured and calculated by the method of converting it with the etching amount of tungsten. The results are as shown in Table 1.

[0110] [Table 1]

[0111] Referring to Table 1, it can be confirmed that when polishing a tungsten (W) film using the polishing slurry according to the production example, the etching rate decreased compared to the case of using the polishing slurry according to the comparative production example, and it was confirmed that the ratio of the polishing rate to the etching rate was good. Also, when polishing a tungsten (W) film using the polishing slurry according to the production example, it was confirmed that the smaller the difference in the LUMO energy level between tungsten (W), the metal to be polished, and the compound having a positively charged functional group contained in the polishing slurry, the higher the polishing rate.

[0112] As described above, the embodiments of the present invention have been described in detail, but the scope of the rights of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims also belong to the scope of the rights of the present invention.

Explanation of Reference Numerals

[0113] 10: Semiconductor substrate 20: Interlayer insulating film 20a: Trench 30: Barrier layer 40: Metal layer 40a: Embedded metal layer 50: Capping layer

Claims

1. A fullerene derivative and at least one compound having at least one positively charged functional group, comprising a polishing slurry, wherein the fullerene derivative is contained in the polishing slurry at 0.005% to 2% by weight, the at least one compound having at least one positively charged functional group is contained in the polishing slurry at 0.001% to 1% by weight, the at least one compound having at least one positively charged functional group is arginine, lysine, or cysteine, or the at least one compound having at least one positively charged functional group includes a first compound containing one positively charged functional group and a second compound containing two or more positively charged functional groups, the first compound is glycine, and the second compound is arginine or lysine, the first compound and the second compound are contained in a weight ratio of 3:1 to 10:1, the fullerene derivative is hydroxylated fullerene, the polishing slurry is used for polishing a tungsten film, a polishing slurry.

2. The polishing slurry according to claim 1, wherein the fullerene derivative is represented by the following chemical formula 1: [Chemical formula 1] C ｘ (OH) ｙ (where x is 60, 70, 74, 76 or 78, and y is an integer from 12 to 44.)

3. The polishing slurry according to claim 1 or 2, wherein the average particle size of the fullerene derivative is less than 10 nm.

4. The polishing slurry according to any one of claims 1 to 3, wherein the at least one compound having at least one positively charged functional group has a LUMO energy level of 4.3 eV or more and 5.3 eV or less.

5. The polishing slurry according to any one of claims 1 to 4, wherein the first compound and the second compound are contained in a weight ratio of 5:1 to 8:

1.

6. The polishing slurry according to any one of claims 1 to 5, wherein the at least one compound having a positively charged functional group has a positive charge in water.

7. The fullerene derivative is contained in the polishing slurry at 0.01% to 0.8% by weight, the compound having a positively charged functional group is contained in the polishing slurry at 0.01% to 0.4% by weight, the polishing slurry according to any one of claims 1 to 6.

8. The polishing slurry according to any one of claims 1 to 7, wherein the pH of the polishing slurry is 1.0 to 7.

0.

9. The polishing slurry according to any one of claims 1 to 8, further comprising an oxidizing agent, a chelating agent, a surfactant, a dispersant, an acidity regulator, a solvent, or a combination thereof.

10. Disposing a semiconductor substrate and a polishing pad opposite to each other; Supplying the polishing slurry according to any one of claims 1 to 9 between the semiconductor substrate and the polishing pad; Contacting the surface of the semiconductor substrate and the polishing pad to perform polishing, and The polishing slurry polishes metal wiring in the semiconductor substrate, A method for manufacturing a semiconductor device, wherein the metal wiring contains tungsten.

11. The method for manufacturing a semiconductor device according to claim 10, wherein a ratio of a polishing rate of the tungsten to an etching rate of the tungsten is 2 or more.

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