Cleaning slurry for semiconductor device and method for manufacturing semiconductor device

Abstract

To provide a method of manufacturing a semiconductor device capable of effectively removing a fine abrasive used for chemical mechanical polishing.SOLUTION: Performing chemical mechanical polishing using a polishing slurry containing an abrasive; and supplying a cleaning slurry containing ductile particles having a lower hardness than a polishing surface and a dispersion medium to the polishing surface on which the chemical mechanical polishing is performed, A first cleaning operation of removing the abrasive from the polishing surface, wherein a zetapotential of one of the ductile particles and the abrasive at a pH of the cleaning slurry is greater than 0, and a zetapotential of the other of the ductile particles and the abrasive at the pH of the cleaning slurry is less than 0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cleaning slurry for semiconductor devices and a method for manufacturing semiconductor devices. [Background technology]

[0002] 2. Description of the Related Art Recently, due to the miniaturization of electronic devices and the resulting miniaturization of integrated circuits, various methods for forming microstructures such as metal wiring or shallow trench isolation having a width of several nanometers have been investigated.

[0003] In the step of forming such a microstructure, a polishing process may be performed to create a flat surface of the microstructure, and one such polishing process 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 (including a thin film such as a dielectric layer or a metal layer) to be polished and a polishing pad, and then the semiconductor substrate is brought into contact with the polishing pad to planarize the surface of the substrate. After the chemical mechanical polishing process, a cleaning step is required to remove remaining abrasives and polishing by-products. Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, fine abrasives measuring several nanometers to several tens of nanometers have been used to effectively perform chemical mechanical polishing on microstructures. However, these fine abrasives adhere to the surface of semiconductor substrates and are difficult to remove. Such fine abrasives that are not removed can cause defects on the semiconductor substrates, affecting productivity.

[0005] One embodiment provides a method for manufacturing a semiconductor device that can effectively remove fine abrasives used in chemical mechanical polishing.

[0006] Another embodiment provides a cleaning slurry for semiconductor devices that can effectively remove fine abrasives used in chemical mechanical polishing. [Means for solving the problem]

[0007] According to one embodiment, there is provided a method for manufacturing a semiconductor device, comprising: a first cleaning step of supplying a cleaning slurry containing ductile particles having a hardness lower than that of the polishing surface and a dispersant to the polishing surface during and after the step of performing chemical mechanical polishing using a polishing slurry containing an abrasive to remove the abrasive from the polishing surface; wherein the zeta potential of either the ductile particles or the abrasive at the pH of the cleaning slurry is greater than 0, and the zeta potential of the other of the ductile particles and the abrasive at the pH of the cleaning slurry is less than 0.

[0008] The difference between the zeta potential of the abrasive and the ductile particles at the pH of the cleaning slurry can be about 20 mV or greater.

[0009] The zeta potential of the ductile particles at the pH of the wash slurry can be between about -10 mV and -140 mV.

[0010] The zeta potential of the abrasive at the pH of the cleaning slurry can be about +10 mV to +140 mV.

[0011] The pH of the washing slurry may be in the range of 2-6.

[0012] The polishing surface can comprise an oxide, a nitride, a carbide, a semiconductor, a semiconductor compound, an organic-inorganic complex compound, a metal, a metal alloy, or a combination thereof.

[0013] The abrasive may include a fine abrasive having a particle size of about 1 nm or more and less than 50 nm.

[0014] The abrasive may include an oxide abrasive, a nitride abrasive, a carbon abrasive, or a combination thereof.

[0015] The abrasive may include a ceria abrasive.

[0016] The dispersion medium may include water.

[0017] The manufacturing method may further include a second cleaning step of removing polishing by-products from the polishing surface, and the second cleaning step may include supplying a chemical solution to remove the polishing by-products from the polishing surface, and contacting a cleaning brush with the polishing surface and / or supplying ultrasound to the polishing surface.

[0018] According to another embodiment, there is provided a method for manufacturing a semiconductor device, the method comprising: performing chemical mechanical polishing using a polishing slurry containing an abrasive; a first cleaning step of supplying a cleaning slurry to the polished surface after the chemical mechanical polishing to remove the abrasive from the polished surface; and a second cleaning step of supplying a chemical liquid to the polished surface after the chemical mechanical polishing and contacting it with a cleaning brush and / or applying ultrasonic waves, wherein the abrasive comprises a fine abrasive having a particle size of 1 nm or more but less than 50 nm, and the cleaning slurry comprises ductile particles larger than the fine abrasive and having a hardness lower than that of the polished surface, and a dispersant.

[0019] The ductile particles can include organic, inorganic, organic-inorganic composites, or combinations thereof, having a negative or positive surface charge.

[0020] The ductile particles can include polymeric beads having a negative or positive surface charge.

[0021] The ductile particles may include hexagonal boron nitride.

[0022] According to another embodiment, there is provided a cleaning slurry for semiconductor devices that is applied after chemical mechanical polishing using a polishing slurry containing an abrasive, the cleaning slurry for semiconductor devices comprising ductile particles including an organic material, an inorganic material, an organic-inorganic composite material, or a combination thereof, and a dispersant, the ductile particles having a zeta potential of -10 mV to -140 mV at the pH of the cleaning slurry.

[0023] The ductile particles may have a Mohs hardness of 1-5.

[0024] The ductile particles may have a particle size of about 30 nm to 2 μm.

[0025] The pH of the polishing slurry may be between 2 and 6.5.

[0026] The cleaning slurry may further include a pH adjuster.

[0027] The ductile particles may comprise about 0.01 to 5% by weight of the cleaning slurry.

[0028] By effectively removing the remaining fine abrasive after chemical mechanical polishing, it is possible to prevent defects in semiconductor devices and a decrease in productivity due to the remaining fine abrasive. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a graph showing the zeta potential of ductile particles according to a synthesis example and a comparative synthesis example as a function of pH. [Figure 2] 1 is an SEM photograph of ductile particles obtained from Synthesis Example 1 before mixing with ceria abrasive. [Figure 3] 1 is an SEM photograph showing ductile particles with adsorbed ceria abrasive after mixing the ductile particles obtained from Synthesis Example 1 with a ceria abrasive. [Figure 4] 1 is an SEM photograph of ductile particles obtained from Synthesis Example 2 before mixing with ceria abrasive. [Figure 5] 1 is an SEM photograph showing ductile particles with adsorbed ceria abrasive after mixing the ductile particles obtained from Synthesis Example 2 with a ceria abrasive. DETAILED DESCRIPTION OF THE INVENTION

[0030] Although the following detailed description of the embodiments will be made in order to enable those skilled in the art to easily implement the present invention, the actual structures may be implemented in various different forms and are not limited to the embodiments described herein.

[0031] Hereinafter, unless otherwise defined, the term "substituted" means that a hydrogen atom in a compound or functional group is substituted with a substituent selected from a halogen atom, a hydroxy group, an alkoxy group, a nitro group, a cyano group, an amino group, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a silyl group, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C7 to C30 arylalkyl group, a C1 to C30 alkoxy group, a C1 to C20 heteroalkyl group, a C3 to C20 heteroaryl group, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C3 to C30 heterocycloalkyl group, and combinations thereof.

[0032] As used herein, "substantially" and "about" include approximate ranges that take into account variations and errors within normal limits, for example, about ±5%, ±4%, ±3%, ±2%, or ±1%.

[0033] Hereinafter, the term "combination" includes mixtures and laminated structures of two or more materials.

[0034] Hereinafter, a cleaning slurry for semiconductor devices according to one embodiment will be described.

[0035] A cleaning slurry for semiconductor devices can be used to clean a solid surface such as the surface of a semiconductor substrate (including a thin film such as a dielectric layer or a metal layer) in the manufacturing process of a semiconductor device, and can be used, for example, to remove remaining abrasives on the polished surface after chemical mechanical polishing (CMP) using an abrasive.

[0036] The cleaning slurry for semiconductor devices according to one embodiment includes soft particles and a dispersion medium.

[0037] Ductile particles can be particles having a relatively low hardness, for example, spherical, plate-like, linear, irregular, and / or amorphous particles having a hardness lower than that of the solid surface to be cleaned.

[0038] For example, the ductile particles may have a lower hardness than the polishing surface (hereinafter referred to as the "polishing surface") that has undergone chemical mechanical polishing. Here, the polishing surface may include oxides such as silicon oxide and aluminum oxide; nitrides such as silicon nitride, aluminum nitride, titanium nitride, or gallium nitride; carbides such as silicon carbide; semiconductors such as silicon or germanium; compound semiconductors such as InP and GaAs; organic-inorganic complex compounds such as tetraethyl orthosilicate (TEOS); metals such as aluminum, copper, molybdenum, or nickel, alloys thereof, or metal oxides or semi-metal oxides produced during the chemical mechanical polishing process; or combinations thereof. The Mohs hardness of the polishing surface may be between 5 and 10. The Mohs hardness of the ductile particles may be lower than the Mohs hardness of the polishing surface, for example, between 1 and 5, and may be between 1 and 4, 1 and 3, or 1 and 2. This may prevent the ductile particles from causing damage such as scratches to the polishing surface when they come into contact with it.

[0039] The ductile particles may be larger than at least some of the abrasives (hereinafter referred to as "abrasives") used in chemical mechanical polishing. The abrasives may include abrasives of various sizes, and for example, the particle size (average particle size) of the abrasives may be in the range of about 1 nm to 150 nm.

[0040] The abrasive may include a fine abrasive, for example, from about 1 nm to less than about 50 nm, about 5 nm to 45 nm, about 10 nm to 40 nm, or about 15 nm to 35 nm, and the ductile particles may be larger than the fine abrasive. The fine abrasive may be, for example, an oxide abrasive, a nitride abrasive, a carbon abrasive, or a combination thereof, such as, but not limited to, ceria abrasive, silica abrasive, silicon nitride abrasive, SiC, diamond, fullerene or fullerene derivative, or a combination thereof. For example, the particle size (including the major axis) of the ductile particles may be at least two times larger than the particle size (major axis) of the fine abrasive, and may be 2 to 2000 times, about 5 to 200 times, about 10 to 100 times, about 15 to 50 times, or about 20 to 30 times larger within the above range.

[0041] The particle size of the ductile particles may be larger than that of the fine abrasive, for example, about 30 nm to 2 μm, about 50 nm to 1500 nm, about 60 nm to 1200 nm, about 80 nm to 1000 nm, or about 100 nm to 500 nm. Here, the particle size may be the average particle size of the particles, and the particle size can be measured by dynamic light scattering (DLS). In this way, by supplying ductile particles larger than the abrasive (fine abrasive) and washing after chemical mechanical polishing, the abrasive (fine abrasive) adhering to the polishing surface can be physically detached.

[0042] The ductile particles may be electrically charged in the cleaning slurry, and thus may have a negative or positive surface charge. The surface charge of the ductile particles may have a surface charge of the opposite sign to that of the target substance to be removed by the cleaning slurry, e.g., the abrasive (fine abrasive). For example, when the abrasive has a positive surface charge, the ductile particles may have a negative surface charge. For example, when the abrasive has a negative surface charge, the ductile particles may have a positive surface charge. Because the ductile particles have a surface charge opposite to that of the abrasive, electrostatic attraction between the ductile particles and the abrasive can effectively occur even without a surfactant, and the abrasive detached from the polishing surface can be effectively prevented from reattaching to the polishing surface and effectively adsorbed to the ductile particles.

[0043] The surface charge can be evaluated by the zeta potential. The zeta potential indicates the electrostatic potential of the particle surface at a given pH, and it is possible to confirm the type and amount of charge carried by the particles. The zeta potential can be measured using electrophoretic mobility by electrophoresis.

[0044] The zeta potential can vary with pH, ​​and at a given pH (e.g., process pH or cleaning slurry pH), the ductile particles have a zeta potential of the opposite sign to that of the abrasive, thereby ensuring electrostatic attraction between the abrasive and the ductile particles. For example, the process pH or cleaning slurry pH can be between 2 and 12, and within this range, can be between 2 and 10, 2 and 8, 2 and 6.5, 2 and 6, 3 and 6.5, 3 and 6, 3.5 and 6.5, 3.5 and 6, or 3.5 and 5.5. For example, the process pH or cleaning slurry pH can be between 2 and 6.

[0045] For example, the ductile particles and the abrasive at the pH of the cleaning slurry can have zeta potentials of opposite signs. For example, the zeta potential of one of the ductile particles and the abrasive at the pH of the cleaning slurry can be greater than 0, and the zeta potential of the other of the ductile particles and the abrasive can be less than 0. In other words, depending on the zeta potential of the abrasive at the pH of the cleaning slurry, ductile particles with a zeta potential less than 0 at the pH of the cleaning slurry can be selected, and ductile particles with a zeta potential greater than 0 at the pH of the cleaning slurry can be selected.

[0046] As an example, the zeta potential of the abrasive at the pH of the cleaning slurry may be greater than 0, and the zeta potential of the ductile particle at the pH of the cleaning slurry may be less than 0. For example, the zeta potential of the ceria abrasive at the pH of the cleaning slurry may be greater than 0, and the zeta potential of the ductile particle at the pH of the cleaning slurry may be less than 0. For example, when using a ceria abrasive, the zeta potential of the ceria abrasive at the pH of the cleaning slurry may be about +10 mV to +140 mV, and the zeta potential of the ductile particle at the pH of the cleaning slurry may be about -10 mV to -140 mV. Within the above ranges, the zeta potential of the ceria abrasive cleaning slurry at the pH may be about +20 mV to +140 mV, about +20 mV to +120 mV, about +30 mV to +120 mV, about +40 mV to +110 mV, about +50 mV to +100 mV, or about +60 mV to +90 mV, and the zeta potential of the ductile particle cleaning slurry at the pH may be about -20 mV to -140 mV, about -20 mV to -120 mV, about -30 mV to -120 mV, about -10 mV to -100 mV, about -10 mV to -90 mV, or about -20 mV to -80 mV.

[0047] As an example, the difference between the zeta potential of the abrasive and the zeta potential of the ductile particles at the pH of the cleaning slurry may be about 20 mV or more, and within the range may be about 20 mV to 280 mV, about 30 mV to 280 mV, about 40 mV to 280 mV, about 50 mV to 280 mV, about 60 mV to 280 mV, about 20 mV to 240 mV, about 30 mV to 240 mV, about 40 mV to 240 mV, about 50 mV to 240 mV, about 60 mV to 240 mV, about 70 mV to 220 mV, about 80 mV to 200 mV, or about 90 mV to 180 mV. When the difference in zeta potential between the abrasive and the ductile particles at the pH of the cleaning slurry is within the above range, a stronger electrostatic attraction acts between the abrasive and the ductile particles, more effectively preventing the abrasive that has detached from the polishing surface from re-adhering to the polishing surface and more effectively adsorbing to the ductile particles.

[0048] In this way, the ductile particles in the cleaning slurry physically detach the remaining abrasives (fine abrasives) from the polished surface after chemical mechanical polishing (CMP), and also prevent the abrasives from re-adhering to the polished surface due to electrostatic attraction, effectively adsorbing to the ductile particles. This effectively removes the remaining abrasives (fine abrasives) after chemical mechanical polishing, preventing semiconductor device defects and reduced productivity due to the remaining fine abrasives. Furthermore, the cleaning slurry can effectively remove the abrasives (fine abrasives) from the polished surface without the need for a separate surfactant. The cleaning slurry, which contains a surfactant, can prevent the effects of surfactant residues on semiconductor devices during cleaning. Furthermore, the process can be simplified by eliminating the need for an additional process for surfactant removal.

[0049] For example, when chemical mechanical polishing (CMP) is performed on a silicon oxide surface using a fine ceria abrasive with a particle size of less than about 50 nm, strong Ce-O-Si bonds are formed on the surface, making it difficult to remove the fine ceria abrasive from the polished surface. To remove the fine ceria abrasive, chemical washing with a strong acid, such as sulfuric acid, and physical washing may be required. In contrast, the cleaning slurry described above brings the fine ceria abrasive into contact with ductile particles larger than the fine ceria abrasive, effectively removing the Ce-O-Si bonds on the surface, effectively desorbing the fine ceria abrasive from the polished surface, and preventing the fine ceria abrasive from reattaching to the polished surface due to electrostatic attraction, effectively adsorbing it to the ductile particles. This allows the fine ceria abrasive to be effectively removed from the polished surface without the need for a separate surfactant in the cleaning slurry.

[0050] The ductile particles can include organic, inorganic, organic-inorganic materials, or combinations thereof, having a negative or positive surface charge. The ductile particles can include organic, inorganic, organic-inorganic materials, or combinations thereof, that exhibit the above-described zeta potential at a predetermined pH (process pH or cleaning composition pH). As an example, the ductile particles can include polymeric particles having the above-described properties, such as spherical polymer beads.

[0051] The polymer particles may include crosslinked or non-crosslinked polymers having a negative or positive surface charge in a dispersion medium (e.g., water). The crosslinked or non-crosslinked polymers may have a negative or positive surface charge in a dispersion medium (e.g., water) as described above, and may have functional groups that determine the surface charge to have such electrical properties. For example, a crosslinked or non-crosslinked polymer having a negative surface charge may have, but is not limited to, a terminal carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid, a salt derived therefrom, or a combination thereof. For example, a crosslinked or non-crosslinked polymer having a positive surface charge may have, but is not limited to, a terminal amine, amidine, trialkylamine, a salt derived therefrom, or a combination thereof. The polymer particles may include, but are not limited to, a polymer having the aforementioned electrical properties while containing, as a structural unit (or repeating unit), styrene having, as a terminal functional group, a carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid, and / or a salt derived therefrom. The polymer particles may include, but are not limited to, polymers having the electrical properties described above while containing, for example, maleic anhydride structural units, itaconic anhydride structural units, citraconic (methylmaleic) anhydride structural units, or other substituted anhydride structural units having carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid, and / or salts derived therefrom as terminal functional groups.

[0052] As mentioned above, the polymeric particles may have a zeta potential of less than 0 at the pH of the washing slurry. For example, the polymeric particles may have a zeta potential of greater than 0 at the pH of the washing slurry. For example, the zeta potential of the polymeric particles at the pH of the washing slurry may be about −10 mV to −140 mV, and within that range may be about −20 mV to −140 mV, about −20 mV to −120 mV, about −30 mV to −120 mV, about −10 mV to −100 mV, about −10 mV to −90 mV, or about −20 mV to −80 mV. For example, the difference between the zeta potential of the abrasive and the zeta potential of the polymer particles at the pH of the cleaning slurry may be about 20 mV or more, and within the range may be about 20 mV to 280 mV, about 30 mV to 280 mV, about 40 mV to 280 mV, about 50 mV to 280 mV, about 60 mV to 280 mV, about 20 mV to 240 mV, about 30 mV to 240 mV, about 40 mV to 240 mV, about 50 mV to 240 mV, about 60 mV to 240 mV, about 70 mV to 220 mV, about 80 mV to 200 mV, or about 90 mV to 180 mV.

[0053] The polymeric particles may be synthesized by various synthesis methods without other surfactants, such as soap-free emulsion polymerization, suspension polymerization, or precipitation polymerization.

[0054] By way of example, the ductile particles can include an inorganic material having the aforementioned properties, such as an oxide, nitride, oxynitride, or combinations thereof having the aforementioned properties, for example, but not limited to, hexagonal boron nitride.

[0055] The ductile particles may be present in the cleaning slurry at up to about 5% by weight, and within the ranges may be present at about 0.01 to 5% by weight, about 0.1 to 5% by weight, about 0.1 to 3% by weight, about 0.1 to 2% by weight, about 0.2 to 2% by weight, about 0.3 to 2% by weight, or about 0.4 to 2% by weight.

[0056] The cleaning slurry may further include a pH adjuster, which adjusts the pH of the cleaning slurry, for example, to 2 to 12, or within the above range, 2 to 10, 2 to 8, 2 to 6.5, 2 to 6, 3 to 6.5, 3 to 6, 3.5 to 6.5, 3.5 to 6, or 3.5 to 5.5.

[0057] The pH adjuster may be, for example, an inorganic acid, an organic acid, an inorganic base, an organic base, a salt thereof, or a combination thereof. The inorganic acid may be, for example, nitric acid, hydrochloric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, bromic acid, iodic acid, or a salt thereof. The organic acid may be, 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, glutaric acid, glutamic acid, glycolic acid, lactic acid, aspartic acid, tartaric acid, or a salt thereof. The inorganic base may be, for example, but is not limited to, NaOH, KOH, or a combination thereof. The pH adjuster may be present in the cleaning slurry in trace amounts, for example, about 1 ppm to 100,000 ppm based on the total content of the cleaning slurry.

[0058] The cleaning slurry may not contain a surfactant, since as mentioned above, the ductile particles may effectively adsorb to the ductile particles, physically detaching the remaining abrasive (fine abrasive) from the polishing surface and preventing the abrasive from redepositing on the polishing surface through electrostatic attraction.

[0059] The dispersion medium may be, for example, water. The water may be, for example, distilled water and / or deionized water. The dispersion medium may be included in the remaining amount excluding solid particles such as ductile particles and pH adjusters.

[0060] The cleaning slurry can be used in a cleaning step after a chemical mechanical polishing (CMP) step. The cleaning slurry can be used before a post-CMP cleaning step, in which physical cleaning and chemical cleaning are performed simultaneously. For example, the cleaning slurry can be applied in a buff cleaning step between a chemical mechanical polishing (CMP) step and a post-CMP cleaning step. That is, by simply supplying the cleaning slurry in the buff cleaning step, remaining fine abrasives, such as fine ceria abrasives, can be effectively removed without physical cleaning using a cleaning brush or ultrasound or chemical cleaning using a chemical solution, unlike the post-CMP cleaning step.

[0061] An example of a method for manufacturing a semiconductor device including the cleaning step will now be described.

[0062] A method for manufacturing a semiconductor device according to one embodiment includes the steps of performing chemical mechanical polishing (CMP) on a surface of an object to be polished, and cleaning the polished surface (polished surface) by supplying a cleaning slurry containing the above-described ductile particles and a dispersant.

[0063] The object to be polished can be a variety of structures, for example, a semiconductor substrate such as a silicon wafer (including a thin film such as a dielectric layer or a metal layer), and the polishing surface can include oxides such as silicon oxide and aluminum oxide; nitrides such as silicon nitride, aluminum nitride, titanium nitride, or gallium nitride; carbides such as silicon carbide; semiconductors such as silicon or germanium; compound semiconductors such as InP and GaAs; organic-inorganic complex compounds such as tetraethylorthosilicate (TEOS); metals such as aluminum, copper, molybdenum, or nickel, alloys thereof, or metal oxides or semi-metal oxides produced during chemical mechanical polishing; or combinations thereof. For example, the polishing surface can include a conductor such as a metal wiring or an insulator such as a shallow trench isolation (STI) or insulating film, for example, the polishing surface can include silicon oxide and / or silicon nitride.

[0064] Chemical mechanical polishing (CMP) can be performed using a chemical mechanical polishing apparatus that can include, for example, a lower base, a rotatable platen provided on the upper surface of the lower base, a polishing pad disposed on the platen, a pad conditioner, and a polishing slurry nozzle disposed adjacent to the polishing pad for supplying a polishing slurry to the polishing pad.

[0065] The platen may be provided rotatably on the surface of the lower base. For example, the platen may receive rotational power from a motor disposed in the lower base. This allows the platen to rotate about an imaginary axis of rotation perpendicular to the surface of the platen. The imaginary axis of rotation may be perpendicular to the surface of the lower base.

[0066] The polishing pad can be positioned 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 roughened polishing surface. Such a polishing surface can directly contact a polishing object, such as a semiconductor substrate, to mechanically polish the surface of the polishing object. The polishing pad can be made of a porous material having a plurality of microspaces, and the plurality of microspaces can receive a polishing slurry. A pad conditioner can be disposed adjacent to the polishing pad to maintain a constant condition of the polishing pad during the polishing process.

[0067] The polishing slurry nozzle may be disposed adjacent to the polishing pad and may supply polishing slurry to the polishing pad. The polishing slurry nozzle may further include a voltage supply unit capable of applying a predetermined voltage. The voltage supplied from the voltage supply unit may charge the polishing slurry in the nozzle and cause it to be ejected toward the polishing pad.

[0068] Chemical mechanical polishing can be performed by, for example, arranging an object to be polished, such as a semiconductor substrate, and a polishing pad so that they face each other, supplying a polishing slurry from a polishing slurry nozzle between the object to be polished and the polishing pad, and contacting the surface of the object to be polished with the polishing pad to perform polishing.

[0069] The polishing slurry may include an abrasive and a dispersion medium. The abrasive may include abrasives of various sizes, for example, with an average particle size of about 1 nm to 150 nm. The abrasive may include, for example, a fine abrasive with a particle size of about 1 nm or more and less than about 50 nm. The fine abrasive may include, for example, an oxide abrasive, a nitride abrasive, a carbon abrasive, or a combination thereof. The oxide abrasive may include, for example, a ceria abrasive. The nitride abrasive may include, for example, silicon nitride. The carbon abrasive may be a two-dimensional or three-dimensional abrasive particle made of or containing carbon, such as SiC, diamond, and / or fullerene or a fullerene derivative (e.g., C60, C70, C74, C76, or C78). The polishing slurry may further include additives, such as, but not limited to, a chelating agent, an oxidizing agent, a surfactant, a dispersant, a pH adjuster, or a combination thereof. The dispersion medium can be water, for example, distilled water and / or deionized water.

[0070] The polishing slurry may be supplied at a rate of about 10 ml / min to 300 ml / min, and may be supplied at a flow rate of, for example, about 2 μl to 10 μl.

[0071] The polishing step can be performed by rotating a polishing pad in contact with the surface of the object to be polished, such as a semiconductor substrate, to generate mechanical friction. For example, a pressure of about 1 psi to 5 psi may be applied during the polishing step.

[0072] After chemical mechanical polishing (CMP), the polished surface (polished surface) can be subjected to a first cleaning. The first cleaning can be separate from post-CMP cleaning, which requires both physical cleaning using a cleaning brush or ultrasonic waves and chemical cleaning using a chemical solution, and can be a step for effectively removing abrasives (fine abrasives) remaining on the polished surface after chemical mechanical polishing.

[0073] The first cleaning can be performed, for example, during the buffing step. Conventional buffing is a process of supplying water (distilled water and / or deionized water) to a heavily contaminated polishing surface to remove contaminants from the polishing surface. However, the first cleaning can be performed by supplying (e.g., spraying) a cleaning slurry containing the ductile particles and a dispersant, instead of water (distilled water and / or deionized water). Therefore, the first cleaning, which cleans the polishing surface by supplying the cleaning slurry, can be performed within the existing process rather than as an additional process. The first cleaning can be performed, for example, prior to post-CMP cleaning (second cleaning).

[0074] The first cleaning can be performed by supplying the cleaning slurry described above to the polishing surface that has undergone chemical mechanical polishing (CMP). The cleaning slurry can be supplied through the polishing slurry nozzle described above or through a separate nozzle. As described above, the cleaning slurry can contain ductile particles that are larger than the abrasive (fine abrasive) and have certain electrical properties. These ductile particles contact the abrasive to effectively detach the abrasive from the polishing surface, and the electrostatic attraction between the ductile particles and the abrasive (fine abrasive) prevents the abrasive (fine abrasive) from reattaching to the polishing surface, allowing it to be effectively adsorbed to the ductile particles. This allows the abrasive (fine abrasive) to be effectively removed from the polishing surface without the need for a separate surfactant in the cleaning slurry. A detailed description of the cleaning slurry is provided above.

[0075] After the first cleaning, post-CMP cleaning (second cleaning) can be performed. Post-CMP cleaning (second cleaning) can remove polishing by-products (e.g., oxides, nitrides, carbides, semiconductors, semiconductor compounds, organic-inorganic complex compounds, metal and / or metal alloy residues) remaining on the polished surface after chemical mechanical polishing (CMP) by physical cleaning using a cleaning brush or ultrasound, and chemical cleaning using a chemical solution.

[0076] For example, the post-chemical mechanical polishing cleaning (second cleaning) may include the steps of supplying a chemical solution to remove polishing by-products from the polishing surface, contacting the polishing surface with a cleaning brush and / or applying ultrasonic waves, and optionally drying and / or heating. The steps of supplying the chemical solution and contacting the polishing surface with a cleaning brush and / or applying ultrasonic waves may be performed simultaneously or sequentially.

[0077] The chemical solution can include, for example, organics, surfactants, and solvents that contain functional groups capable of chemically bonding (eg, coordinate, hydrogen, and / or ionic bonding) with polishing by-products.

[0078] The cleaning brush may have a cylindrical body and multiple protrusions that can rotate in a predetermined direction. The cylindrical body may be fitted to a predetermined rotation axis (not shown) and may contact the polishing surface while rotating in either a clockwise or counterclockwise direction. The multiple protrusions increase the friction between the cleaning brush and the polishing surface as the cleaning brush rotates, effectively separating polishing by-products present on the polishing surface from the polishing surface. The cleaning brush may include a polymer, such as a porous polymer that can effectively absorb and discharge liquids such as water and cleaning solutions without damaging the polishing surface (e.g., the surface of a semiconductor substrate). Examples of the porous polymer include, but are not limited to, polyvinyl alcohol (PVA)-based polymers, polyurethane (PU)-based polymers, or combinations thereof.

[0079] Drying and / or heating can be carried out, for example, at a temperature of about 25 to 200 degrees, which can dry the chemical liquid remaining on the polishing surface by spraying or the like, and can also improve the performance of the physical cleaning and / or chemical cleaning described above.

[0080] The above-mentioned embodiments will be described in more detail below through examples, which are provided for illustrative purposes only and are not intended to limit the scope of the invention.

[0081] Synthesis Example Synthesis Example 1 A solution was prepared by adding 1 g of sodium styrene sulfonate and 880 mL of deionized water to a double-walled glass reactor equipped with a mechanical stirrer, N2 inlet, and reflux condenser. The solution was then heated to 70°C and purged with N2, after which 100 g of styrene and 1 g of potassium persulfate were added. Polymerization was carried out for 18 hours at 70°C under a N2 atmosphere to obtain a ductile particle dispersion. After the reaction, the ductile particle dispersion was filtered through a glass filter to obtain ductile particles.

[0082] Synthesis Example 2 A three-neck flask equipped with a N2 inlet and reflux condenser was charged with 7.35 g of maleic anhydride, 6.51 g of divinylbenzene, 0.28 g of 2,2-azobisisobutyronitrile (AIBN), 250 ml of butyl acetate, and 125 ml of heptane. After all reactants were dissolved, the solution was purged with N2, and the flask was placed in an oil bath at 90 °C for 2 hours for polymerization. The polymerized ductile particles were separated by centrifugation and washed with butyl acetate and petroleum ether. The product was then dried overnight under vacuum. The anhydride functional groups were hydrolyzed to acid groups via the sodium salt using sodium hydroxide and hydrochloric acid. The final ductile particles were washed several times with water and ethanol and dried under vacuum to obtain ductile particles.

[0083] Synthesis Example 3 Ductile particles were obtained in the same manner as in Synthesis Example 1, except that 0.07 g of sodium styrenesulfonate was used instead of 1 g.

[0084] Synthesis Example 4 A 100 mL three-neck flask equipped with a N2 inlet and reflux condenser was charged with 2.93 g of maleic anhydride, 2.49 g of triallyl isocyanurate, 0.16 g of 2,2-azobisisobutyronitrile (AIBN), 13 g of isoamyl acetate, and 8.7 g of cyclohexane. After all reactants were dissolved, the solution was purged with N2, and the flask was placed in an oil bath at 75 °C for 5 h for polymerization. The polymerized ductile particles were separated by centrifugation and washed with isoamyl acetate and petroleum ether. The product was then dried overnight under vacuum. The anhydride functional groups were converted to sodium maleate groups by reaction with sodium hydroxide. Finally, the resulting ductile particles were washed several times with water and ethanol and dried under vacuum to obtain ductile particles.

[0085] Comparative Synthesis Example 1: A solution was prepared by dissolving 1.008 g of (vinylbenzyl)trimethylammonium chloride in 720 mL of deionized water in a double-walled glass reactor equipped with a mechanical stirrer, N2 inlet, and reflux condenser. The solution was then heated to 65°C and purged with N2, after which 80 g of styrene and 0.8 g of 2,2-azobis(2-methylpropionamidine) dihydrochloride were added. Polymerization was carried out for 6 hours at 65°C under an N2 atmosphere to obtain a ductile particle dispersion. After the reaction, the ductile particle dispersion was filtered through a glass filter to obtain ductile particles.

[0086] Rating I The size and zeta potential of the ductile particles obtained from the synthesis example and the comparative synthesis example were evaluated according to pH.

[0087] The zeta potential as a function of size and pH of the ductile particles was measured using a NanoPartica particle analyzer SZ-100VZ (Horiba). The zeta potential as a function of pH was measured while varying the pH of the ductile particle dispersions prepared by dispersing the ductile particles obtained from the synthesis example and the comparative synthesis example in deionized water, from 3 to 6.5.

[0088] The results are shown in Table 1 and FIG.

[0089] FIG. 1 is a graph showing the zeta potential of ductile particles according to a synthesis example and a comparative synthesis example as a function of pH.

[0090] [Table 1]

[0091] Referring to Table 1, it can be seen that the ductile particles obtained from the Synthesis Examples and Comparative Synthesis Examples have an average particle size of about 100 nm to 1200 nm.

[0092] Referring to FIG. 1, it can be seen that the ductile particles obtained from the Synthesis Examples exhibit a negative zeta potential within a given pH range (the pH of the ductile particle dispersion, for example, a range of 3 to 6.5), while the ceria abrasive and the ductile particles obtained from Comparative Synthesis Example 1 exhibit a positive zeta potential.

[0093] It is therefore expected that the high electrostatic repulsion between the ductile particles will result in high dispersion stability of the cleaning slurry, and that a strong electrostatic attraction will act between the ductile particles of the synthesis example and the ceria abrasive.

[0094] Rating II The adsorption performance of the fine abrasives of ductile particles obtained from the synthesis examples was evaluated.

[0095] The adsorption performance of the fine abrasive was evaluated by adding ceria abrasive (average particle size: approximately 25 nm, Sigma-Aldrich) to a ductile particle dispersion (pH = 4) prepared by dispersing the ductile particles obtained from the synthesis examples in deionized water, mixing, and drying the mixture, and then observing the image using a scanning electron microscopy (SEM).

[0096] The results are shown in Figures 2 to 5.

[0097] Figure 2 is an SEM photograph of a ductile particle obtained from Synthesis Example 1 before mixing with a ceria abrasive, Figure 3 is an SEM photograph showing a ductile particle with adsorbed ceria abrasive after mixing the ductile particle obtained from Synthesis Example 1 with a ceria abrasive, Figure 4 is an SEM photograph of a ductile particle obtained from Synthesis Example 2 before mixing with a ceria abrasive, and Figure 5 is an SEM photograph showing a ductile particle with adsorbed ceria abrasive after mixing the ductile particle obtained from Synthesis Example 2 with a ceria abrasive.

[0098] 2 and 3, it can be seen that a large amount of ceria abrasive is adsorbed on the surface of the ductile particles obtained from Synthesis Example 1. Similarly, it can be seen that a large amount of ceria abrasive is adsorbed on the surface of the ductile particles obtained from Synthesis Example 2.

[0099] This confirms that there is sufficient electrostatic attraction between the ductile particles obtained from the synthesis example and the ceria abrasive, and therefore it is expected that the ductile particles obtained from the synthesis example can effectively remove the ceria abrasive from the polishing surface.

[0100] Preparation of cleaning slurry Manufacturing Example 1 A washed slurry was prepared by diluting the ductile particles obtained from Synthesis Example 1 with deionized water to a solids content of 0.5 wt%. The washed slurry was sonicated for 10 minutes before use. The washed slurry did not contain surfactants or other stabilizers.

[0101] Manufacturing Example 2 The ductile particles from Synthesis Example 2 were diluted with deionized water to a solids content of 0.5 wt% and sonicated for 10 minutes to prepare a washed slurry. The pH was adjusted by adding HCl. The washed slurry did not contain surfactants or other stabilizers.

[0102] Manufacturing Example 3 A washing slurry was prepared in the same manner as in Production Example 1, except that the ductile particles obtained from Synthesis Example 3 were used instead of the ductile particles obtained from Synthesis Example 1.

[0103] Manufacturing Example 4 A cleaning slurry was prepared by diluting hexagonal boron nitride (mean particle size: approximately 200 nm) as ductile particles with deionized water to a solids content of 2.0 wt%. The cleaning slurry was ultrasonically treated for 10 minutes before use. The cleaning slurry did not contain surfactants or other stabilizers.

[0104] Manufacturing Example 5 The ductile particles from Synthesis Example 4 were diluted with deionized water to a solids content of 0.5 wt% and sonicated for 10 minutes to prepare a washed slurry. The pH was adjusted by adding HCl. The washed slurry did not contain surfactants or other stabilizers.

[0105] Comparative Manufacturing Example 1 A washed slurry was prepared by diluting the ductile particles obtained from Comparative Synthesis Example 1 with deionized water to a solids content of 0.5 wt %. The washed slurry was sonicated for 10 minutes before use. The washed slurry did not contain surfactants or other stabilizers.

[0106] Rating III The zeta potential of the ductile particles contained in the cleaning slurries of the Example and Comparative Example was evaluated. The zeta potential of the cleaning slurries was measured using a Nano Partica particle analyzer SZ-100VZ (Horiba).

[0107] The results are shown in Table 2.

[0108] [Table 2]

[0109] Referring to Table 2, it can be seen that the ductile particles contained in the cleaning slurry according to Comparative Preparation Example 1 exhibit a positive zeta potential at the pH of the cleaning slurry, while the ductile particles contained in the cleaning slurries according to Preparation Examples 1 to 5 exhibit a negative zeta potential at the pH of the cleaning slurry.

[0110] As a result, the high electrostatic repulsion between the ductile particles results in high dispersion stability of the cleaning slurry, and it is expected that a strong electrostatic attraction acts between the ductile particles contained in the cleaning slurries of Preparation Examples 1 to 5 and the ceria abrasive.

[0111] Rating IV The hardness of the ductile particles contained in the cleaning slurry of the Manufacturing Example was evaluated by spraying the cleaning slurry of the Manufacturing Example onto a wafer on which a silicon oxide film (Mohs hardness: 6.5) had been deposited, and determining whether scratches were generated on the surface of the silicon oxide film.

[0112] The results are shown in Table 3.

[0113] [Table 3]

[0114] Referring to Table 3, it can be seen that the cleaning slurry according to the Preparation Example does not cause scratches on the surface of the silicon oxide film, and therefore, it can be seen that the hardness of the ductile particles contained in the cleaning slurry according to the Preparation Example is lower than the hardness of the silicon oxide film. [Example]

[0115] Example 1 A ceria polishing slurry was prepared by dispersing colloidal ceria abrasive (N10, DITTO) in deionized water. The average particle size of the ceria abrasive was 15 nm. A wafer with a silicon oxide film deposited thereon was subjected to chemical mechanical polishing (CMP) using a Bruker-CP4 under the conditions shown in Table 4 below. The CM-polished wafer was then immersed in the ceria polishing slurry for 1 minute, rinsed with deionized water, and dried under nitrogen flow to prepare a contaminated sample. The contaminated sample was then cleaned using the cleaning slurry prepared in Preparation Example 1. The cleaning was performed for 120 seconds using the same pad (IT-2000, KPX Chemical Co.) as used for CMPA under the same conditions (Table 4) as used for CMPA.

[0116] Example 2 Cleaning was carried out in the same manner as in Example 1, except that the cleaning slurry of Preparation Example 2 was used instead of the cleaning slurry of Preparation Example 1.

[0117] Example 3 Cleaning was carried out in the same manner as in Example 1, except that the cleaning slurry of Preparation Example 3 was used instead of the cleaning slurry of Preparation Example 1.

[0118] Example 4 Cleaning was carried out in the same manner as in Example 1, except that the cleaning slurry of Preparation Example 4 was used instead of the cleaning slurry of Preparation Example 1.

[0119] Example 5 Cleaning was carried out in the same manner as in Example 1, except that the cleaning slurry of Preparation Example 5 was used instead of the cleaning slurry of Preparation Example 1.

[0120] Example 6 Washing was carried out in the same manner as in Example 1, except that washing was carried out for 60 seconds.

[0121] Example 7 Washing was carried out in the same manner as in Example 1, except that washing was carried out for 30 seconds.

[0122] Example 8 Ceria polishing slurry was prepared by dispersing ceria particles (Sigma Aldrich) in deionized water at 0.2 wt %. The average particle size of the ceria particles was 25 nm. A wafer with a silicon oxide film deposited on it was immersed in the ceria polishing slurry for 1 minute, rinsed with deionized water, and dried under nitrogen flow to prepare a contaminated sample. The contaminated sample was then cleaned using the cleaning slurry from Preparation Example 1. Cleaning was performed for 120 seconds under the same conditions as for chemical mechanical polishing (CMP) (Table 4), with the cleaning slurry from Preparation Example 1 sprayed onto the contaminated sample.

[0123] Example 9 Washing was carried out in the same manner as in Example 8, except that washing was carried out for 60 seconds.

[0124] Example 10 Cleaning was carried out in the same manner as in Example 8, except that the cleaning head pressure was changed as shown in Table 4.

[0125] Example 11 Cleaning was carried out in the same manner as in Example 8, except that cleaning was carried out for 60 seconds and the cleaning head pressure was changed as shown in Table 4.

[0126] Comparative Example 1 Cleaning was carried out in the same manner as in Example 1, except that deionized water was used instead of the cleaning slurry from Preparation Example 1.

[0127] Comparative Example 2 Cleaning was carried out in the same manner as in Example 1, except that the cleaning slurry of Comparative Preparation Example 1 was used instead of the cleaning slurry of Preparation Example 1.

[0128] [Table 4]

[0129] Rating V The surfaces of the contaminated samples were observed before and after cleaning in the examples and comparative examples. The surface roughness of the contaminated sample surfaces before and after cleaning was measured using an AFM (NX20, Park system Co.). The concentration of Ce ions on the surface of the contaminated samples before and after cleaning was measured using an X-ray photoelectron spectrometer (XPS Quantera II, Ulvac-PHI).

[0130] The results are shown in Table 5.

[0131] [Table 5]

[0132] Referring to Table 5, it can be seen that after cleaning according to the example, the ceria abrasive was completely removed and the surface roughness of the contaminated sample was significantly reduced. In contrast, cleaning according to Comparative Example 1 using water and cleaning according to Comparative Example 2 using ductile particles with the same zeta potential as the ceria abrasive left a considerable amount of remaining ceria abrasive, and the surface roughness of the contaminated sample was also relatively high. This confirms that cleaning according to the example is effective in removing ceria abrasive from the surface of the contaminated sample.

[0133] Although the embodiments have been described in detail above, the scope of the invention is not limited to these examples, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the claims below also fall within the scope of the invention.

Claims

1. performing chemical mechanical polishing using a polishing slurry containing an abrasive; and a first cleaning step of supplying a cleaning slurry containing ductile particles having a hardness lower than that of the polished surface and a dispersion medium to the polished surface that has been subjected to the chemical mechanical polishing, thereby removing the abrasive from the polished surface; Including, the zeta potential of either the ductile particles or the abrasive at the pH of the cleaning slurry is greater than 0; The method for manufacturing a semiconductor device, wherein the zeta potential of the other of the ductile particles and the abrasive at the pH of the cleaning slurry is less than 0.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the difference between the zeta potential of the abrasive and the ductile particles at the pH of the cleaning slurry is 20 mV or more.

3. 2. The method of claim 1, wherein the zeta potential of the ductile particles at the pH of the cleaning slurry is −10 mV to −140 mV.

4. 2. The method of claim 1, wherein the zeta potential of the abrasive at the pH of the cleaning slurry is +10 mV to +140 mV.

5. 2. The method of claim 1, wherein the pH of the cleaning slurry is in the range of 2 to 6.

5.

6. The method of claim 1 , wherein the polishing surface comprises an oxide, a nitride, a carbide, a semiconductor, a semiconductor compound, an organic-inorganic complex compound, a metal, a metal alloy, or a combination thereof.

7. The method of manufacturing a semiconductor device according to claim 1 , wherein the abrasive comprises a fine abrasive having a particle size of 1 nm or more and less than 50 nm.

8. The method of claim 1 , wherein the abrasive comprises an oxide abrasive, a nitride abrasive, a carbon abrasive, or a combination thereof.

9. The method for manufacturing a semiconductor device according to claim 1 , wherein the abrasive includes a ceria abrasive.

10. further comprising a second cleaning step of removing polishing by-products from the polishing surface; The second washing step comprises: providing a chemical solution to remove the polishing by-products from the polishing surface; and contacting the polishing surface with a cleaning brush or applying ultrasonic waves; The method for manufacturing a semiconductor device according to claim 1 , comprising:

11. performing chemical mechanical polishing using a polishing slurry containing an abrasive; a first cleaning step of supplying a cleaning slurry to the polishing surface that has been subjected to the chemical mechanical polishing to remove the abrasive from the polishing surface; and a second cleaning step in which a chemical solution is supplied to the polished surface that has been subjected to chemical mechanical polishing, and a cleaning brush is brought into contact with the polished surface and / or ultrasonic waves are applied; Including, The abrasive includes a fine abrasive having a particle size of 1 nm or more and less than 50 nm, The cleaning slurry has a hardness lower than that of the polishing surface and contains ductile particles larger than the fine abrasive and a dispersion medium.

12. The method of claim 11 , wherein the ductile particles comprise an organic material, an inorganic material, an organic-inorganic composite material, or a combination thereof, having a negative or positive surface charge.

13. The method of claim 11 , wherein the ductile particles comprise polymeric beads having a negative or positive surface charge.

14. The method of manufacturing a semiconductor device according to claim 11 , wherein the ductile particles comprise hexagonal boron nitride.

15. A cleaning slurry for semiconductor devices that is applied after chemical mechanical polishing using a polishing slurry containing an abrasive, Ductile particles comprising organic, inorganic, organic-inorganic, or a combination thereof, exhibiting a zeta potential of −10 mV to −140 mV at the pH of the cleaning slurry; and dispersion medium, A cleaning slurry for semiconductor devices comprising:

16. 16. The cleaning slurry for semiconductor devices according to claim 15, wherein the ductile particles have a Mohs hardness of 1 to 5.

17. 16. The cleaning slurry for semiconductor devices according to claim 15, wherein the ductile particles have a particle size of 30 nm to 2 μm.

18. 16. The cleaning slurry for semiconductor devices according to claim 15, wherein the polishing slurry has a pH of 2 to 6.

19. The cleaning slurry for a semiconductor device according to claim 15, further comprising a pH adjuster.

20. 16. The cleaning slurry for semiconductor devices according to claim 15, wherein the ductile particles are contained in an amount of 0.01 to 5 wt % based on the weight of the cleaning slurry.

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