JP2003017447A - Cmp abrasives and method for polishing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide CMP abrasives capable of obtaining a highly planarized substrate by rapidly polishing, without generating polishing damages by reducing unevenness in a surface of a polishing speed, and to provide a method for polishing the substrate. SOLUTION: The method for polishing the substrate comprises steps of supplying the CMP abrasives containing cerium oxide particles, water-soluble polymer, water soluble organic fluorocompound and water, in such a manner that the surface tension is 5 mN/m to 50 mN/m for the polishing pad on the polishing platen, and polishing the surface of the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CMP polishing agent used in a flattening process of a substrate surface, which is a semiconductor element manufacturing technique, in particular, a flattening process of an interlayer insulating film, a shallow trench isolation forming process, and the like. The present invention relates to a method for polishing a substrate using these CMP abrasives.

[0002]

2. Description of the Related Art In the current ultra-large scale integrated circuits, there is a tendency to increase the packaging density, and various fine processing techniques have been researched and developed. Already, the design rules are on the order of sub-half micron. CMP (Chemical Mechanical P) is one of the technologies developed to satisfy such strict miniaturization requirements.
There is an illuminating technology. This technique can completely flatten the layer to be exposed in the manufacturing process of the semiconductor device, reduce the burden of the exposure technique, and stabilize the yield, so that, for example, the flattening of the interlayer insulating film or the shallow trench. This is an indispensable technique when performing separation and the like.

Conventionally, LOCO is used for element isolation in an integrated circuit.
Although the S (silicon local oxidation) method has been used, the shallow trench isolation method has been used in recent years in order to narrow the element isolation width. In the shallow trench isolation method, CMP is indispensable to remove the excess silicon oxide film formed on the wafer substrate, and a silicon nitride film is formed as a stopper under the silicon oxide film to stop polishing. It is common to

In the process of manufacturing a semiconductor device, plasma-CVD (Chemical Vapor Depos) is used.
CMP for planarizing a silicon oxide insulating film and the like formed by a method such as an ionization method, a chemical vapor deposition method) or a low pressure-CVD method.
As the polishing agent, conventionally, an alkaline silica-based polishing agent having fumed silica as polishing particles and having a pH of more than 9 has been widely used. On the other hand, an abrasive containing cerium oxide as abrasive particles, which has been frequently used as a glass surface abrasive for photomasks, lenses and the like, has recently attracted attention as a CMP abrasive. This technique is disclosed in, for example, Japanese Patent Laid-Open No. 5-326.
It is disclosed in Japanese Patent Publication No. 469. Cerium oxide-based abrasives are superior to silica-based abrasives in that they have a faster polishing rate for silicon oxide films and comparatively less polishing scratches, so various application studies have been conducted, and some of them have been commercialized as semiconductor abrasives. It is supposed to be done. This technique is disclosed in, for example, Japanese Patent Laid-Open No. 9-270402.

In recent years, as the number of layers of semiconductor elements has increased and the resolution has increased, further improvement in the yield and throughput of semiconductor elements has been demanded. Also for the semiconductor substrate obtained after the CMP polishing, there is a tendency that further flattening, that is, improvement of in-plane uniformity of substrate film thickness is desired. As a method of obtaining a highly planarized substrate,
The polishing characteristics of the polishing agent and the optimization of the polishing process may be mentioned. The optimization of the polishing process means polishing under the polishing conditions in which there is no in-plane variation in the polishing rate. For that purpose, it is essential that the polishing agent is evenly and evenly supplied to the surface of the polishing pad. However, generally, the surface tension of the resin constituting the polishing pad is within the range of 10 to 50 mN / m, which is lower than 73 mN / m of water, which is the main component of the polishing agent, so that the so-called " It is difficult to suppress the "repellency", and there is a problem that the polishing agent cannot be evenly and uniformly supplied. The present invention is a polishing agent in which cerium oxide is dispersed in water, and the surface tension of the polishing agent is brought close to that of the polishing pad constituent resin to solve the above problems. It is another object of the present invention to provide a CMP polishing agent capable of reducing the in-plane variation of the polishing rate and obtaining a highly flattened substrate, and a substrate polishing method using this polishing agent.

[0006]

According to the invention of claim 1, it is possible to obtain a highly flattened substrate by reducing the in-plane variation of the polishing rate and performing high-speed polishing without generating polishing scratches. It provides a CMP abrasive. Further, the invention according to claim 2 provides a method for polishing a substrate, which can reduce in-plane variation in polishing rate and can perform high-speed polishing without generating polishing scratches to obtain a highly flattened substrate. To do.

[0007]

The present invention relates to a CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water and having a surface tension of 5 mN / m or more and 50 mN / m or less. Further, the present invention is a semiconductor chip on which a silicon oxide insulating film is formed by supplying a CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water to a polishing pad on a polishing platen. It is characterized in that the surface of the substrate is polished by bringing the surface of the substrate into contact with the surface to be polished of the substrate and moving the polishing pad relative to each other, and polishing the surface of the substrate through a polishing pad in which a CMP abrasive having a weakened surface tension of water is distributed. The present invention relates to a method for polishing a substrate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cerium oxide particles according to the present invention are obtained by calcining or oxidizing a cerium compound of carbonate, nitrate, sulfate or oxalate. In the examples of the present invention, firing or oxidation with hydrogen peroxide or the like can be used as a method for producing the cerium oxide powder. The firing temperature is preferably 350 ° C or higher and 900 ° C or lower.
Since the cerium oxide particles produced by the above method are agglomerated, it is preferable to mechanically grind them. As the crushing method, a dry crushing method using a jet mill or a wet crushing method using a planetary bead mill is preferable. The jet mill is, for example, a collection of chemical industry papers, Vol. 6, No. 5 (1980) 527.
~ P.532.

The CMP polishing agent in which the surface tension of the polishing agent is close to that of the resin for forming the polishing pad is to wash the cerium oxide particles synthesized by the above method, and to dissolve the water-soluble polymer, water-soluble organic fluorine compound, water and, if necessary, water. It is obtained by dispersing the composition to which a dispersant has been added accordingly. For washing, a method in which solid-liquid separation is repeated several times by centrifugation or the like can be used.

The degree of reduction in surface tension varies depending on the type of the water-soluble organic fluorine compound, but it is relatively easy to adjust an abrasive having any surface tension. However, the surface tension of the CMP abrasive must be 5 mN / m or more and 50 mN / m or less, and more preferably 10 mN / m or more and 40 mN / m or less. When the surface tension is less than 5 mN / m, the ability of holding the CMP abrasive on the pad surface is lowered, and the polishing rate tends to be lowered. Surface tension is 50m
If it is larger than N / m, it tends to be difficult to equalize the CMP abrasive concentration distribution on the pad surface. Examples of the surface tension measuring method include the annular method by Dunui and the vertical plate method by Wilhelmy. The pH of the CMP abrasive is
It is preferably 3 or more and 9 or less, and more preferably 5 or more and 8 or less. When the pH is less than 3, the chemical action becomes small and the polishing rate is lowered. If the pH is higher than 9, the particles agglomerate and the contact area with the film to be polished decreases.
The polishing rate tends to decrease. Further, since it is used for polishing semiconductor chips, it is preferable to keep the content of alkali metals and halogens in the cerium oxide particles to 10 ppm or less.

It is generally considered that the cerium oxide particles dispersed in water are not completely separated one by one, and the measured value of the particle diameter of cerium oxide dispersed in water is in the powder state. It is larger than the primary particle size measurement value obtained by using a method such as SEM photography. The secondary particle diameter of cerium oxide dispersed in water is preferably 1 nm or more and 300 nm or less. If the secondary particle diameter is smaller than 1 nm, the effect of the abrasive grains on the film to be polished is reduced, and the polishing rate is reduced. When the secondary particle diameter is larger than 300 nm, the contact area with the film to be polished becomes small and the polishing rate tends to decrease. The particle size is measured by a photon correlation method (for example, Zetasizer 3000HS manufactured by Malvern Instruments Ltd.). Also,
The primary particle size of cerium oxide is larger than 0 nm and 300
It is necessary to be less than nm. When the primary particle size is 0 nm, the silicon oxide film is not polished at all. If the crystallite size is larger than 300 nm, the secondary particle size will be larger than 300 nm and the polishing rate will decrease.

Although the concentration of cerium oxide particles is not limited,
The range of 0.5% by weight or more and 20% by weight or less is preferable from the viewpoint of easy handling of the dispersion.

As the water-soluble polymer, polyvinyl sulfonic acid, polymethacrylic acid, polystyrene sulfonic acid, polyacrylic acid, polyacrylic acid derivative, poly (4-vinylpyridinium salt), poly (1 (3-sulfonyl) -2
-Vinylpyridinium betaine-co-p-styrene sulfonic acid), polyvinyl alcohol derivative, polyacrolein, poly (vinyl acetate-co-methyl methacrylate), poly (styrene-co-maleic anhydride), poly (olefin-co- Maleic anhydride), polyacrylamide partial hydrolyzate, poly (acrylamide-co-
Acrylic acid), alginic acid, polymethyl acrylate, polymethyl methacrylate, and water-soluble anionic surfactants such as ammonium salts, amine salts or potassium salts of polyacrylic acid or polymethacrylic acid; water-soluble polyvinylpyrrolidone, etc. At least one selected from nonionic surfactants can be used, and preferably,
Polymethacrylic acid, polyacrylic acid, polyvinyl alcohol derivative, polyacrylamide partial hydrolyzate, poly (acrylamide-co-acrylic acid), ammonium salt of polyacrylic acid or polymethacrylic acid, and amine salt can be used. Here, the amine salt is N,
Examples thereof include salts with N-dimethylaminoethanol. The weight average molecular weight of the water-soluble polymer is 1000
-100,000 are preferable. There is no particular limitation on the ratio of the number of moles of the monomer unit of the water-soluble polymer / the number of moles of the water-soluble polymer and the amine that forms a salt, but it is necessary to set the pH of the polishing agent to 3 or more and 9 or less, and therefore 10/7 or more It is preferably 10/14 or less. The water-soluble polymer needs to be mixed with the CMP abrasive so that the amount thereof is 1 to 3 times the weight of the cerium oxide particles. If the amount is less than 1 times by weight, the effect of the water-soluble polymer is weakened and the flattening property is deteriorated. If the amount exceeds 3 times by weight,
The polishing rate tends to be low. Further, the concentration of the water-soluble polymer is preferably 1 to 5 weight from the viewpoint of handleability, mixing workability and the like.

As the water-soluble organic fluorine compound, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl sulfonate, perfluoroalkyl trimethyl ammonium salt, perfluoroalkyl aminosulfone sun salt, perfluoroalkyl group / hydrophilic group-containing At least one selected from oligomers and the like can be used. The concentration of these water-soluble organic fluorine compounds,
The range of 0.0001% by weight or more and 1.0% by weight or less is preferable, and the range of 0.0005% by weight or more and 0.005% by weight or less is more preferable. If it is 0.0001% by weight or less, the desired surface tension cannot be obtained, and even if it is added in an amount of 1.0% by weight or more, the surface tension does not change, which adversely affects the dispersibility of the cerium oxide particles.

As the CMP abrasive, a composition in which a dispersant is added to the abrasive as necessary to disperse the composition can be used. As the dispersant, in addition to the above-mentioned water-soluble polymer, at least one selected from water-soluble anionic dispersants, water-soluble nonionic dispersants, water-soluble cationic dispersants, and water-soluble amphoteric dispersants. It is possible to use two or more dispersants including Examples of the water-soluble anionic dispersant include triethanolamine lauryl sulfate, ammonium lauryl sulfate, triethanolamine polyoxyethylene alkyl ether sulfate, and the like, but anionic water-soluble polymers described later may also be used. As the water-soluble nonionic dispersant, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octylphenyl ether, Polyoxyethylene nonyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, Polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, tetraoleic acid poly Xyethylene sorbit, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol monooleate, polyoxyethylene alkylamine, polyoxyethylene hydrogenated castor oil, alkyl alkanolamide, etc. Examples of the water-soluble cationic dispersant include coconut amine acetate and stearyl amine acetate, and examples of the water-soluble amphoteric dispersant include lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, and 2-alkyl-N. -Carboxymethyl-N
-Hydroxyethyl imidazolinium betaine and the like can be mentioned. The amount of these dispersants added is in the range of 0.01 parts by weight or more and 2.0 parts by weight or less with respect to 100 parts by weight of the cerium oxide particles in view of dispersibility and prevention of sedimentation, and the relationship between polishing scratches and the amount of the dispersants added. Is preferred. As a method for dispersing these cerium oxide particles in water, a homogenizer, an ultrasonic disperser, a wet ball mill, or the like can be used in addition to the usual dispersion treatment using a stirrer.

As a method for producing an inorganic insulating film to be polished with a CMP polishing agent, a constant pressure CVD method, a plasma CVD method and the like can be mentioned. In forming the silicon oxide insulating film by the constant pressure CVD method, monosilane: SiH _{4 is} used as the Si source, and oxygen: O ₂ is used as the oxygen source. It is obtained by carrying out this SiH ₄ —O ₂ system oxidation reaction at a low temperature of about 400 ° C. or lower. When phosphorus: P is doped to achieve surface flattening by high temperature reflow, SiH ₄ —O ₂ —P
It is preferable to use an H ₃ -based reaction gas. Plasma CV
Method D has the advantage that chemical reactions that require high temperatures under normal thermal equilibrium can be performed at low temperatures. There are two plasma generation methods, a capacitive coupling type and an inductive coupling type. The reaction as a gas, SiH ₄ as an Si source, an oxygen source as _{N 2} O was used was _SiH 4 -N ₂ O-based gas and _{TEOS-O 2} based gas using tetraethoxysilane (TEOS) in an Si source (TEOS- Plasma CVD method). The substrate temperature is 250 ° C to 400 ° C, and the reaction pressure is 67 to 400 Pa.
Is preferred. Elements such as phosphorus and boron may be doped in the silicon oxide insulating film. Similarly, low pressure CVD
The silicon nitride film is formed by the method as follows: dichlorosilane: SiH ₂ Cl ₂ as a Si source and ammonia: NH 3 as a nitrogen source.
To use. This SiH ₂ Cl ₂ —NH ₃ system oxidation reaction is
It is obtained by carrying out at a high temperature of 00 ° C. The plasma CVD method uses SiH ₄ as a Si source and NH as a nitrogen source.
₃ include _SiH 4 -NH ₃ based gas was used. The substrate temperature is preferably 300 to 400 ° C.

As the substrate, as shown in FIGS. 1A and 1B, a semiconductor substrate, that is, a semiconductor substrate at a stage where a circuit element and a wiring pattern are formed, a semiconductor substrate at a stage where a circuit element is formed, and the like. A substrate having a silicon oxide film or a silicon oxide film and a silicon nitride film formed thereon can be used. By polishing the silicon oxide film layer formed on such a semiconductor substrate with the above-mentioned polishing agent, unevenness on the surface of the silicon oxide film layer is eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate.
Specifically, it is a semiconductor chip having a silicon oxide insulating film formed by supplying a CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water to a polishing pad on a polishing platen. The surface of the substrate is polished by bringing the surface of the substrate and the polishing pad into relative motion by bringing them into contact with the surface of the substrate to be polished, and polishing the surface of the substrate through the polishing pad in which the CMP polishing agent having the surface tension of water weakened is distributed. In the case of shallow trench isolation, the lower silicon nitride layer is polished while eliminating the irregularities of the silicon oxide film layer, leaving only the silicon oxide film embedded in the element isolation portion. At this time, if the polishing rate ratio with respect to the silicon nitride serving as the stopper is large, the polishing process margin becomes large. Further, in order to use for shallow / trench separation, it is also necessary that the number of scratches generated during polishing is small.
Here, as a polishing device, a general polishing device having a holder for holding a semiconductor substrate and a surface plate to which a polishing cloth (pad) is attached (a motor or the like whose rotation speed is changeable) is used is used. it can. FIG. 2 is a schematic diagram showing a CMP apparatus used in the present invention. A CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water is supplied onto the polishing pad 17 attached on the polishing platen 18 to form a substrate 1 which is a semiconductor chip.
The silicon oxide insulating film 14 formed in 3 is attached to the wafer holder 11 as a surface to be polished, the silicon oxide insulating film 14 is brought into contact with the polishing pad, and the surface to be polished and the polishing pad are relatively moved,
Specifically, the wafer holder 11 and the polishing platen 18 are rotated to perform CMP, that is, polishing of the substrate.
As the polishing pad, general non-woven fabric, polyurethane foam, porous fluororesin, etc. can be used without any particular limitation. Further, it is preferable that the polishing pad is grooved so that the polishing agent is accumulated. The polishing conditions are not limited, but the rotation speed of the surface plate is preferably low rotation of 100 rpm or less so that the semiconductor does not jump out. The pressing pressure of the semiconductor substrate having the film to be polished against the polishing pad is preferably 10 to 100 kPa, and 20 to 50 kPa is required to satisfy the in-plane uniformity of the polishing rate and the flatness of the pattern.
Is more preferable. During polishing, a polishing agent is continuously supplied to the polishing pad by a pump or the like. Although there is no limitation on the supply amount, it is preferable that the surface of the polishing pad is always covered with the abrasive.

FIG. 3 is a diagram showing a CMP process in the present invention. In order to perform CMP with the surface state of the polishing pad always the same, a polishing pad conditioning step is inserted before CMP. Specifically, polishing is performed with a liquid containing at least water using a dresser with diamond particles. Subsequently, the polishing step of the present invention is performed, and further, 1) brush cleaning for removing foreign matters such as particles adhered to the substrate after polishing 2) megasonic cleaning for replacing abrasives with water 3) A wafer cleaning step consisting of spin drying to remove water from the substrate surface is added. It is preferable that the semiconductor substrate after the polishing is thoroughly washed in running water, and then water droplets adhering to the semiconductor substrate are removed by using a spin dryer or the like and then dried. Thus, after forming the shallow trench isolation on the Si substrate, the silicon oxide insulating film layer and the aluminum wiring are formed thereon, and the silicon oxide insulating film formed thereon is flattened. A second layer of aluminum wiring is formed on the flattened silicon oxide insulating film layer, and a silicon oxide film is formed again between the wirings and on the wiring by the above method, and then polished with the above polishing agent. As a result, the unevenness on the surface of the silicon oxide insulating film is eliminated and the entire surface of the semiconductor substrate is made smooth. By repeating this process a predetermined number of times, a semiconductor having a desired number of layers is manufactured.

The CMP abrasive is not only a silicon oxide film or a silicon nitride film formed on a semiconductor substrate, but also a silicon oxide film formed on a wiring board having a predetermined wiring, an inorganic insulating film such as glass or silicon nitride, Optical glass such as photomasks, lenses and prisms, inorganic conductive films such as ITO, optical integrated circuits, optical switching elements and optical waveguides composed of glass and crystalline materials, optical fiber end faces, optics such as scintillators It is used for polishing substrates such as semiconductor single crystals for lasers, solid-state lasers single crystals, LED sapphire substrates for blue lasers, semiconductor single crystals for SiC, GaP, GaAs, etc., glass substrates for magnetic disks, magnetic heads, etc. .

[0020]

EXAMPLES The present invention will be described below with reference to examples. Example 1 (Preparation of Additive Solution A) 2 kg of cerium carbonate hydrate was placed in a platinum container and baked in the air at 850 ° C. for 2 hours to obtain about 1 kg of cerium oxide powder. 1 kg of the cerium oxide powder prepared above, 11 g of a 40% aqueous solution of ammonium polyacrylate (weight average molecular weight 10,000) in which the ratio of the number of moles of carboxyl groups in the polymer to the number of moles of ammonium ions in the polymer was adjusted to 1: 1; Fluoroalkyl group-containing oligomer (Dega Nippon Ink Megafac F-
171) 1 g and deionized water 18988 g were mixed.
The mixture was subsequently subjected to ultrasonic dispersion for 10 minutes with stirring. The product obtained by further filtering through a 1 μm filter was used as an additive liquid A (cerium oxide particle concentration: 6% by weight). (Preparation of Additive Solution B) A weight average molecular weight of 4000, a ratio of the number of moles of carboxyl groups in the polymer and the number of moles of ammonium ions in the polymer was adjusted to 1: 1 and polyacrylic acid ammonium salt was diluted with deionized water, A 4% by weight aqueous solution (additive solution B) was used. (Preparation of Abrasive) The additive liquid A and the additive liquid B were mixed at a weight ratio of 1: 3, and the cerium oxide particle concentration was 1.5% by weight, the polymer concentration was 1% by weight, and the perfluoroalkyl group-containing oligomer concentration was A 0.001 wt% CMP abrasive was made. The pH of the polishing agent was 6.8. When the secondary particle diameter was measured by a photon correlation method using an abrasive stock solution, the median value was 280 nm. Further, the surface tension of the abrasive was 37 mN / m as measured by the annular method by Dunui using a surface tension measuring device (TOMBO BORL, manufactured by Furukawa Seisakusho).

(Polishing of Insulating Film Layer and Shallow Trench Separation Layer) Al wiring Li having a Line / Space width of 0.05 to 5 mm and a height of 1000 nm is formed on an 8-inch Si substrate.
After forming the ne portion, TEOS-plasma CV is formed on the ne portion.
An insulating film layer patterned wafer having a silicon oxide film formed to a thickness of 2000 nm is manufactured by the D method. Polished for 3 minutes with the above CMP polishing agent (plate rotation speed: 50 rpm, polishing load: 30 kP
a, supply amount of abrasive: 200 ml / min). as a result,
The step difference between the convex portion and the concave portion after polishing was 40 nm, which showed high flatness. Further, as shown in FIG. 1A, a convex portion having a side of 350 nm to 0.1 mm square and a depth of 4 is formed on an 8-inch Si substrate.
The concave portion of 00 nm is formed, and the convex portion density is 2 to 40, respectively.
%, A shallow trench isolation layer patterned wafer was prepared. Subsequently, as shown in FIG. 1B, a nitric oxide film having a thickness of 100 nm was formed on the convex portion, and a silicon oxide film having a thickness of 600 nm was formed thereon by the TEOS-plasma CVD method. This patterned wafer was polished for 2 minutes with the above CMP polishing agent (plate rotation number: 50 rpm, polishing load: 30 kPa, polishing agent supply rate: 200 ml / min). As a result,
As shown in (c), the polishing of the convex portion is stopped by the silicon nitride film,
The level difference after polishing was 42 nm, showing high flatness. No polishing scratches were observed in any polishing.

(Polishing of Insulating Film Layer Blanket Wafer) Next, an 8-inch silicon oxide film blanket wafer was polished with the above CMP polishing agent (plate rotation number: 50 rpm, polishing load: 30 kPa, polishing agent supply amount: 200 ml). / Minute). After polishing, the wafer was removed from the holder and washed with a PVA sponge brush while flowing deionized water. After cleaning, the wafer was rotated on a spin dryer at 1000 rpm for 1 minute to remove water droplets. As a result, the outer peripheral portion 5
The average polishing rate at 49 points on concentric circles within the range excluding mm is 150 nm / min. Using the measured film thickness after polishing at 49 points, film thickness uniformity = (film thickness maximum value− The film thickness uniformity calculated by substituting into the formula of (film thickness minimum value) / (film thickness maximum value + film thickness minimum value) × 100 was 3%. No polishing scratches were observed.

Comparative Example 1 (Preparation of Abrasive) 1 g of a perfluoroalkyl group-containing oligomer used in the preparation of the additive liquid A of Example 1
Eliminate 0 and the amount of deionized water accordingly 18
A CMP polishing slurry was prepared in the same manner as in Example 1 except that the amount was changed from 988 g to 18989 g. The pH of the abrasive was 6.8, and the median secondary particle diameter was 270 nm.
The surface tension of the abrasive was 71 mN / m.

(Polishing of Insulating Film Layer and Shallow Trench Separation Layer) Using the CMP polishing agent prepared as described above, the same insulating film layer patterned wafer as in Example 1 was polished under the same polishing conditions for 5 minutes. As a result, the step difference between the convex portion and the concave portion after polishing was 41 nm. Further, using the above CMP abrasive, a nitric oxide film having a thickness of 100 nm was formed on the convex portion of the shallow trench isolation layer pattern wafer in the same manner as in Example 1, and a silicon oxide film was formed thereon by TEOS-plasma CVD method.
The 0 nm film was polished for 4 minutes under the same polishing conditions as in Example 1. As a result, the step difference after polishing was 44 nm, indicating high flatness. No polishing scratches were observed in any polishing. (Polishing of Insulating Film Layer Blanket Wafer) Next, Example 1
The same 8-inch silicon oxide film blanket wafer and silicon nitride film blanket wafer were also polished using the above CMP polishing agent under the same polishing conditions as in Example 1,
The polishing rate and the film thickness uniformity were calculated. As a result, the polishing rate was 146 nm / min, and the film thickness uniformity after polishing was 10%. No polishing scratches were observed.

Example 1 in which the CMP polishing agent amount distribution on the pad surface was made uniform by using a CMP polishing agent containing a water-soluble organic fluorine compound and having a surface tension of 5 mN / m or more and 50 mN / m or less. On the other hand, in Comparative Example 1, the polishing rate is the same, but the film thickness uniformity after polishing is poor.

[0026]

According to the present invention, it is possible to provide a CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water and having a surface tension of 5 mN / m or more and 50 mN / m or less. . Further, by using this polishing agent to polish the substrate surface through a polishing pad in which a CMP polishing agent having a weakened surface tension of water is distributed, in-plane variation in polishing rate is reduced and polishing scratches are generated. It is possible to apply a substrate polishing method capable of obtaining a highly planarized substrate by performing high-speed polishing without performing the polishing.

[Brief description of drawings]

FIG. 1 is an explanatory view showing flattening of unevenness on a substrate surface of the present invention.

FIG. 2 is a diagram showing a CMP apparatus embodying the present invention.

FIG. 3 is an explanatory diagram showing a CMP process of the present invention.

FIG. 4 is an explanatory diagram showing the correlation between the water-soluble organic fluorine compound concentration and the surface tension in the CMP polishing slurry of the present invention.

[Explanation of symbols]

1 Si Substrate 2 Silicon Nitride Film 3 Silicon Oxide Film, 11 Wafer Holder 12 Retainer 13 Semiconductor Chip Substrate 14 Silicon Oxide Insulating Film 15 Abrasive Supplying Mechanism 16 Cerium Oxide Particles Water-Soluble Polymer Water-Soluble Organic Fluorine Compound and Polishing Containing Water Agent 17 Polishing pad 18 Polishing surface plate

Claims (2)

[Claims] 1. A surface tension including cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water is 5 mN / m.
A CMP abrasive having a content of 50 mN / m or less. 2. A semiconductor chip on which a silicon oxide insulating film is formed by supplying a CMP abrasive containing cerium oxide particles, a water-soluble polymer, a water-soluble organic fluorine compound and water to a polishing pad on a polishing platen. It is characterized in that the surface of the substrate is polished by bringing the surface of the substrate into contact with the surface to be polished of the substrate and moving the polishing pad relative to each other, and polishing the surface of the substrate through a polishing pad in which a CMP abrasive having a weakened surface tension of water is distributed. Substrate polishing method.