KR20010004982A - Method of manufacturing a slurry for polishing an oxide film in a semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a slurry polishing an oxide layer of a semiconductor device is provided to improve a polishing characteristic of a slurry by manufacturing colloidal silica particles formed with silica powders of uniform and small sizes. CONSTITUTION: A hydrolysis process is performed by dissolving a TEOS and a distilled water into an isopropyl alcohol according to various mixing ratios of the isopropyl alcohol. A muriatic acid of an ammonium of a predetermined ratio are added to the resultant of the hydrolysis. A colloidal silica sol is generated therefrom. An abrasive powder is manufactured by drying the colloidal silica sol. The silica abrasive powder is reacted with a basic solution.

Description

Method for manufacturing a slurry for polishing an oxide film in a semiconductor device

The present invention relates to a method for producing an oxide film polishing slurry of a semiconductor device.

Generally, a slurry used for planarization of an oxide in a chemical mechanical polishing (CMP) process includes fine silica (SiO ₂ ) in a basic solution. Such a slurry includes colloidal silica and silica depending on the shape of the abrasive after the manufacturing process. It can be roughly classified as fumed silica.

The method for producing colloidal silica is as follows. First, water is added to sodium silicate as a starting material and hydrolyzed. Then, couples the ^{Na2 +, K +, Ca2 +} , to extract the alkali component, such as Mg2 ⁺ and acidity (pH) of 2 to 3 or an acidic silica sol by cation exchange method primarily. An oxide film polishing silica having a final pH range of 10 to 11 is prepared by combining a basic solution such as NaOH or Na ₂ Si ₂ O ₈ for particle size stability of the abrasive silica particles. Commercial slurries prepared in this manner include Fujimi's 4101 oxide film slurry and Rodel's Klebosol 1050 oxide film slurry.

The manufacturing method of fumed silica is as follows. First, a silica composite is obtained by spray pyrolysis while simultaneously supplying oxygen and hydrogen to silicon chloride (SiCl ₄ ) as a starting material. Thereafter, primary fumed silica abrasive grains are extracted from the silica composite by removing the HCl component and the water component, and the slurry is prepared by dispersing it in a basic solution together with a dispersant by a mechanical method. Commercial slurries prepared in this manner include Cabot's SS series and Moyco's P-1500 slurry.

Of these silica slurry manufacturing process, precisely controlling the chemical manufacturing process up to the first synthesized abrasive has an important effect on the physical properties of the final slurry, such as the purity, average particle size and distribution and specific gravity of the abrasive particles, This requires careful review and control. As a result of applying a series of commercially available slurries to polishing, a large amount of scratches and contamination of the polished film surface are a serious problem, which is considered to be caused by the particle size irregularity of the abrasive particles contained in the slurry. .

Accordingly, the present invention can improve the particle size uniformity of the slurry and improve the polishing properties by preparing the cooidal silica particles of the silica powder having a very uniform and small particle size by the sol-gel powder synthesis method and the supercritical drying method. It is an object of the present invention to provide a method for producing an oxide film polishing slurry of a semiconductor device.

Method for producing an oxide film polishing slurry of a semiconductor device according to the present invention for achieving the above object is a step of dissolving the TEOS dissolved in isopropanol with distilled water, hydrochloric acid, ammonia while varying the mixing ratio of isopropanol; Hydrochloric acid and ammonia are added to the result of the hydrolysis at different ratios according to the respective sol conditions, thereby reacting the colloidal silica sol according to the respective sol conditions; Determining the characteristics of acidity, viscosity, concentration, etc. of each colloidal silica sol solution and preparing a silica abrasive powder by supercritical drying reaction of each colloidal silica sol solution; And reacting the silica abrasive powder with a basic solution.

The present invention introduces a sol-gel powder synthesis method and a supercritical precursor method in the production method of abrasive particles for preparing a slurry, thereby producing colloidal silica particles of silica powder having excellent uniformity and fine particle size. It is possible to prepare a slurry having excellent polishing properties and to compensate for the disadvantages caused by the particle size unevenness of the slurry. More specifically described as follows.

As starting materials for preparing abrasive particles of the slurry according to the present invention, TEOS, isopropanol and distilled water are used, and hydrochloric acid (HCl) and ammonia (NH ₄ OH) solutions are used as acidic and basic catalysts.

First, a certain amount of TEOS is dissolved in isopropanol. At this time, in order to adjust the size of the abrasive particles according to the viscosity it is reacted by changing the mixing ratio of the isopropanol to TEOS and distilled water. For example, TEOS: isopropanol: distilled water = 1: X (X = 3, 6, 9): 1 Add and react to rapidly hydrolyze for 1 hour. In addition, during the hydrolysis, the reaction vessel is stirred vigorously to speed up the reaction rate. Hydrochloric acid and ammonia were added in different ratios according to the respective sol conditions for peptification to control the viscosity of the sol to be formed thereafter and the particle size in the sol. The reaction is carried out for a time to obtain a colloidal silica sol. The amount of hydrochloric acid added to adjust the viscosity and final particle size of the colloidal silica sol is 1.5 to 2.0 x 10 ^-3 moles per 1 mole of TEOS, and the amount of ammonia is 7.5 to 8.5 x 10 ^-3 moles per 1 mole of TEOS. Be sure to Then, the characteristics of the acidity, viscosity, concentration, etc. of each of the colloidal silica sol solution synthesized. Next, the various kinds of sol solutions thus prepared are subjected to supercritical drying at 250 ° C. and 1100 to 1160 psi to obtain silica abrasive powder for preparing the final slurry. Thereafter, the silica abrasive powder is combined with the basic solution to produce a final slurry.

As described above, the present invention can expand the range of slurry that can be selected by producing co-idal silica particles of silica powder having a very uniform and small particle size by sol-gel powder synthesis method and supercritical drying method. In addition, there is an effect that can improve the particle size uniformity of the slurry and ensure excellent polishing characteristics.

Claims (6)

Hydrolyzing TEOS by dissolving it in isopropanol with distilled water while varying the mixing ratio of isopropanol; Hydrochloric acid and ammonia are added to the result of the hydrolysis at different ratios according to the respective sol conditions, thereby reacting the colloidal silica sol according to the respective sol conditions; Determining the characteristics of acidity, viscosity, concentration, etc. of each colloidal silica sol solution and preparing a silica abrasive powder by supercritical drying reaction of each colloidal silica sol solution; A method for producing an oxide film polishing slurry of a semiconductor device comprising the step of reacting the silica abrasive powder with a basic solution. The method of claim 1, Mixing ratio of the TEOS, distilled water and isopropanol is TEOS: isopropanol: distilled water = 1: X (X = 3, 6, 9): 1 method for producing a slurry for polishing oxide film of a semiconductor device. The method of claim 1, Wherein said hydrolysis is performed for 1 hour. The method of claim 1, The reaction process of adding hydrochloric acid and ammonia to the product of the hydrolysis is carried out for 2 hours. The method of claim 1, The amount of hydrochloric acid added to the product of the hydrolysis is 1.5 to 2.0 × 10 ^-3 mol per 1 mol of TEOS, and the amount of ammonia is 7.5 to 8.5 × 10 ^-3 mol per 1 mol of TEOS A method for producing an oxide film polishing slurry of an element. The method of claim 1, The supercritical drying reaction is a slurry manufacturing method for the oxide film polishing of a semiconductor device, characterized in that carried out at 250 ℃, 1100 to 1160psi conditions.