Nissan Chemical Industries Limited

Isao Ota

Tohru Nishimura

Kenji Tanimoto

Toshio Kasai

Noriyuki Takakuma

Takao Kaga

Kiyomi Ema

Gen Yamada

Hideo Sakata

Yoshitane Watanabe

Osamu Tanegashima

Tadafumi Ajiri

Kunio Arai

Yoshiyuki Kashima

Yutaka Ohmori

Natsumi Tsuihiji

Jun Tamaki

Noriyuki Takakura

Shin-ichi Yuki

[Problems to Be Solved] To provide a method for obtaining a polishing composition by which a polishing speed is high and the polished surface has little surface failure. [Means to Solve the Problems] The present invention relates to a production method of a polishing composition containing zirconia oxide sol including: baking at a temperature ranging from 400 to 1000&#xb0; C., a zirconium compound having d50 (where d50 represents a particle diameter meaning that the number of particles having this particle diameter or less is 50% of the total number of particles) of zirconium compound particles of 5 to 25 &#x3bc;m and d99 (where d99 represents a particle diameter meaning that the number of particles having this particle diameter or less is 99% of the total number of particles) of zirconium compound particles of 60 &#x3bc;m or less, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry; and wet-grinding a powder of zirconium oxide obtained in the above baking in an aqueous medium until d50 of zirconium oxide particles becomes 80 to 150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm, wherein d50 and d99 are measured by measuring the slurry of the zirconium compound by a laser diffractometry. [Selected Drawings]None.

Production method of polishing composition

There is provided an abrasive used for polishing a substrate which comprises silica as a main component, for example a rock crystal, a quartz glass for photomask, for CMP of an organic film, Inter Layer Dielectric (ILD) and shallow trench isolation of a semiconductor device, or for polishing a hard disk made of glass. A sol which particles are dispersed in a medium, wherein the particles have a particle size of 0.005 to 1 &#x3bc;m and comprise as a main component crystalline cerium oxide of the cubic system and as an additional component a lanthanum compound, a neodymium compound or a combination thereof, wherein the additional component is contained in X/(Ce+X) molar ratio of 0.001 to 0.5 in which X is lanthanum atoms, neodymium atoms or a combination thereof. The sol is prepared by reacting an aqueous solution which a cerium (III) salt is mixed with a lanthanum (III) salt and/or a neodymium (III) salt, with an alkaline substance to give a suspension in which cerium (III) hydroxide is homogeneously mixed with lanthanum (III) hydroxide and/or neodymium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension.

Cerium oxide sol and abrasive

A production method of a semiconductor device including: producing a polishing composition containing zirconium oxide sol; and planarizing a substrate having an uneven surface with said polishing composition, wherein the polishing composition containing zirconium oxide is produced by the steps comprising: baking at a temperature ranging from 400 to 1000&#xb0; C., a zirconium compound having d50 (where d50 represents a particle diameter meaning that the number of particles having this particle diameter or less is 50% of the total number of particles) of zirconium compound particles of 5 to 25 &#x3bc;m and d99 (where d99 represents a particle diameter meaning that the number of particles having this particle diameter or less is 99% of the total number of particles) of zirconium compound particles of 60 &#x3bc;m or less, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry; and wet-grinding a powder of zirconium oxide obtained in the above baking in an aqueous medium until d50 of zirconium oxide particles becomes 80 to 150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry.

The present invention provides an abrasive compound suitable for polishing the surface of a glass substrate for an optical disk platter or a magnetic disk platter. More specifically, the present invention provides an abrasive compound for a glass hard disk platter, characterized as comprising a stable slurry having water and, dispersed therein as an abrasive, cerium(IV) oxide particles having an average secondary particle size of 0.1 to 0.5 &#x3bc;m and containing CeOin a concentration of 0.2 to 30 wt %. Preferably, the present invention provides the above abrasive compound in which cerium amounts for 95% or more in terms of oxides of the total amount of rare earth elements in the abrasive.

Abrasive compound for glass hard disk platter

A method of milling cerium compound by means of a ball mill using a milling medium, characterized in that ratio H/r of radius r of a cylindrical ball mill container and depth Hof the milling medium in the ball mill container disposed horizontally ranges from 1.2 to 1.9, and the ball mill container is rotated at a rotational speed which is 50% or less of critical rotational speed N=299/rof the ball mill container converted from the radius r expressed in centimeter. The milling method can be carried out in a wet or dry process, and the cerium compound is preferably cerium oxide. The method can be also applied for producing a cerium compound slurry.

Method of milling cerium compound by means of ball mill

The production method for cerium oxide particles of the present invention is a method of producing a cerium oxide particle by heating a cerium compound from a normal temperature to a temperature range of 400&#xb0; C. to 1200&#xb0; C., and comprises at least a temperature raising stage of a temperature rise speed of 2&#xb0; C./hour to 60&#xb0; C./hour, or proceeds via a stage of heating while supplying a humidified gas in a temperature raising process. By the method of the present invention, a cerium oxide powder whose particle diameter distribution of primary particles is narrow can be obtained. An aqueous cerium oxide slurry produced from the powder enables an improvement in the productivity and a reduction in the cost of a polishing step, because if it is used as an abrasive a high-quality polished face is obtained without deteriorating the polishing speed. The aqueous cerium oxide slurry of the present invention is particularly useful as an abrasive for final finish of a substrate whose main component is silica.

Cerium oxide particles and production method therefor

For aluminum disks and glass-made hard disks, those disks having a mean waviness of less than 3 &angst; are being desired in order to increase the density of memory capacity. The present invention provides polishing compositions that can give smoothly polished surfaces for the disks. The polishing compositions are polishing compositions for aluminum disks or substrates having silica on the surface thereof, which contain colloidal silica particle groups having different particle size distributions and have a SiO concentration of 0.5 to 50% by weight.

Polishing composition

Substantially monodisperse crystalline ceric oxide sols and processes for producing such sols are provided. Sols include crystalline ceric oxide particles having a particle size I (particle size converted from specific surface area by gas absorption method) ranging from 10 nm to 200 nm and a ratio of particle size II (particle size measured by dynamic light scattering method) to particle size I ranging from 2 to 6. Sols can be prepared by reacting a cerium (III) salt with an alkaline substance in an aqueous medium under an inert gas atmosphere to obtain a suspension of cerium (III) hydroxide, immediately blowing oxygen or a gas containing oxygen into the suspension to obtain a sol comprising crystalline ceric oxide particles, and wet grinding the resulting sol. Sols are also prepared by calcining cerium carbonate at a temperature of 300 to 1100&deg; C. to give cerium oxide particles, and wet-grinding the resulting particles.

Crystalline ceric oxide sol and process for producing the same

Production of an alumina powder characterized by having a single or multiple crystal structure selected from the group consisting of &ggr;, &dgr; and &thgr;-forms, a primary particle size of 10 to 50 nm, a mean secondary particle size of 100 to 500 nm, and a granular primary particle shape, or an alumina powder characterized by having an a-form crystal structure, a primary particle size of 60 to 150 nm, a mean secondary particle size of 200 to 500 nm, and a granular primary particle shape, using as a raw material an alumina hydrate comprising rectangular plate-like primary particles having a boehmite structure and having a length of one side of 10 to 50 nm; and preparation of a polishing composition comprising the alumina powder, water and a polishing accelerator.

Alumina powder, process for producing the same and polishing composition

The present invention relates to a polishing composition for polishing alumina disks, polishing substrates having silica surfaces and semiconductor wafers, comprising a stable aqueous silica sol containing moniliform colloidal silica particles having a ratio (D /D ) of a particle diameter D nm (as measured by dynamic light scattering method) to a mean particle diameter D (as measured by nitrogen absorption method) of 3 or more, wherein D is between 50 to 800 nm and D is between 10 to 120 nm, said moniliform colloidal silica particles being composed of spherical colloidal silica particles and a metal oxide-containing silica bond which bonds these spherical colloidal silica particles together, wherein the spherical colloidal silica particles are linked together in rows in only one plane by observation through an electron microscope, and further wherein said polishing composition contains 0.5 to 50% by weight of said moniliform colloidal silica particles.

According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 &mgr;m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce ) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95&deg; C. and at an atmospheric pressure.

Polishing abrasive of crystalline ceric oxide particles having surfaces modified with hydroxyl groups

A sensor for detecting a gas comprises a gas detecting portion comprising an anhydrous zinc antimonate semiconductor. The sensor for detecting a gas is preferably hydrogen sulfide. A method for producing the sensor for detecting a gas comprising the steps of: mixing a zinc compound with colloidal antimony oxide in a ZnO/Sb,O,molar ratio of 0.8 to 1.2; calcining the mixture at 300 to 680&deg; C. and grinding the mixture to form electroconductive anhydrous zinc antimonate powder; preparing a sol of the electroconductive anhydrous zinc antimonate; coating the sol of the electroconductive anhydrous zinc antimonate on a substrate of a device; and heating the substrate at a temperature exceeding 680&deg; C., but below 1,000&deg; C.

Anhydrous zinc antimonate semiconductor gas sensor and method for producing the same

A method of producing electroconductive anhydrous zinc antimonate, comprising the steps of mixing a zinc compound and a colloidal antimony oxide in a ZnO/Sb.sub.2 O.sub.5 molar ratio of 0.8 to 1.2; and calcining the mixture of 300 to 680.degree. C. in a gas containing steam to produce an electroconductive anhydrous zinc antimonate having a ZnO/Sb.sub.2 O.sub.5 molar ratio of 0.8 to 1.2 and a primary particle diameter of 5 to 100 nm. The substance is useful as an antistatic agent, an ultraviolet absorbent, a heat ray absorbent, and a sensor, for example.

Method of producing anhydrous zinc antimonate

A polishing composition for an aluminum disk includes water, an alumina abrasive agent and a polishing accelerator. The polishing accelerator is preferably basic aluminum nitrate. A process for polishing an aluminum disk using the polishing composition is also provided.

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Nei-gun, Japan

Isao Ota