KR102005303B1 - A polishing slurry composition - Google Patents

Abstract

The polishing slurry composition of the present invention is superior to conventional chemical-mechanical polishing slurry compositions in terms of polishing efficiency and dispersion stability, minimizes scratches on the surface to be polished, and achieves excellent polishing efficiency in various types of wafers.
Further, the present invention can minimize the defects and scratches on the polished surface by using the modified maleic acid copolymer as the polishing assistant, and it is possible to provide an abrasive for semiconductor wafer processing, biochemical, energy, catalyst, structural materials such as biomedical, It can be widely used for energy environmental materials such as application.

Description

[0001] The present invention relates to a polishing slurry composition,

The present invention relates to a chemical-mechanical polishing slurry composition, and more particularly, to a polishing slurry composition which is excellent in polishing efficiency and dispersion stability, maintains excellent dispersion characteristics for a long period of time, To a chemical-mechanical polishing slurry composition capable of minimizing scratches on a surface to be polished.

Since the line width of the wiring pattern becomes finer and the structure becomes more and more multilayered due to the high integration and high performance of semiconductor devices, the interlayer flatness in each process is very important for improving the precision of photolithography.

The CMP process is an oxide CMP process, a metal CMP process, a poly-Si CMP process, and the like, depending on the material to be polished. And so on.

In order to polish an oxide film, a CMP slurry composition containing silica particles is mainly used. However, since a design rule becomes smaller and a device becomes thinner and planarization becomes necessary, a polishing selection ratio for a wafer in which a heterogeneous film exists A CMP slurry composition containing high cerium oxide particles was applied.

That is, the CMP slurry composition containing cerium oxide particles has a high polishing rate for the silicon oxide film and a very low polishing rate for the silicon nitride film. Therefore, when the stepped silicon oxide film and the silicon nitride film are polished together, the silicon oxide film is polished, The nitride film may have an etching termination function to finish polishing. Therefore, by applying the CMP slurry composition containing such cerium oxide particles to the oxide film CMP process, global planarization and precise control of the polishing thickness are possible.

On the other hand, in recent years, high integration and high density of semiconductor devices are required, and as the line width of the wiring pattern becomes finer and the device becomes thinner, the importance of the scratch reduction that may occur on the wafer surface is increasing.

Since the scratch level is directly related to the production yield, there is an increasing demand for CMP slurry compositions having low scratch characteristics.

Korean Patent Publication No. 10-2013-0078791 (Jul. 10, 2013)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a styrene-maleic acid copolymer as a polishing assistant, which improves dispersion stability of a metal oxide as an abrasive and suppresses generation of defects and scratches of wafers, It is an object of the present invention to provide a polishing slurry composition.

The present invention relates to a polishing composition comprising: a) one or two or more polishing agents selected from aluminum oxide, silicon oxide, zirconium oxide and cerium oxide; b) a polishing aid which binds to the surface of the polishing compound to improve the dispersibility of the polishing compound; And c) a liquid carrier, wherein the polishing assistant has a structure represented by the following formula (1).

[Chemical Formula 1]

(In the above formula (1), n is 1 to 30 and m is 5 to 1,000.)

In one embodiment of the present invention, the abrasive is characterized by being cerium oxide.

In one embodiment of the present invention, the polishing slurry composition is selected from trimethanolamine, triethanolamine, trimethylammonium hydroxide, triethylammonium hydroxide, dimethylbenzylamine, ethoxybenzylamine, sodium hydroxide and potassium hydroxide Lt; RTI ID = 0.0 > pH < / RTI >

In one embodiment of the present invention, the polishing slurry composition is characterized in that it comprises 1 to 30% by weight of an abrasive, 1 to 30% by weight of a polishing aid, and a residual liquid carrier.

The slurry composition according to the present invention is excellent in polishing efficiency and dispersion stability, minimizes scratches on the polished surface, and is superior in chemical-mechanical polishing slurry such as PE-TEOS (Plasma Enhanced-Tetra Ethylene Ortho Silicate) Film, silicon nitride film and the like can be achieved.

In addition, the present invention can minimize defects and scratches on the polished surface and maintain excellent dispersion characteristics for a long period of time by using styrene-maleic acid copolymer as a polishing assistant, and can provide abrasives for semiconductor wafer processing, biomedical, Can be widely used for energy environmental materials such as biochemistry, energy, catalyst, and application of structural materials.

1 is a graph showing the pH stability of the slurry composition of the present invention.
2 is a graph showing the conductivity stability of the slurry composition of the present invention.
3 is a graph showing the viscosity stability of the slurry composition of the present invention.
4 is a graph showing the stability of the average particle size of the abrasive contained in the slurry composition of the present invention.

Hereinafter, the present invention will be described in detail based on examples. It is to be understood that the terminology, examples and the like used in the present invention are merely illustrative of the present invention in order to more clearly explain the present invention and to facilitate understanding of the ordinary artisan, and should not be construed as being limited thereto.

Technical terms and scientific terms used in the present invention mean what the person skilled in the art would normally understand unless otherwise defined.

The chemical-mechanical polishing slurry composition of the present invention may comprise an abrasive, a polishing aid, and a liquid carrier.

The abrasive is for polishing the surface of the wafer, and can be used without limitation as long as it is commonly used in the wafer CMP process. Examples of the metal oxide include metal oxides and more specifically may include one or more selected from aluminum oxide, silicon oxide, zirconium oxide, cerium oxide, titanium oxide, magnesium oxide, molybdenum oxide, have.

The abrasive may be selected from the group consisting of aluminum oxide, silicon oxide, zirconium oxide, cerium oxide, and combinations thereof. More preferably, the use of cerium oxide is preferable because the particle size is uniform and the hardness of the particles is Is preferable.

The particle size of the abrasive is preferably 50 to 1,000 nm, and the particle size can be measured using a particle size analyzer (Horiba device or the like) or laser diffraction method.

When the particle size of the abrasive is less than 50 nm, the polishing rate and the polishing efficiency are lowered. When the particle size exceeds 1,000 nm, scratches and defects of the surface to be polished are rather increased.

Further, according to the present invention, by using two types of particles having different sizes of the abrasive, defects and scratches on the surface to be polished can be minimized without reducing the polishing rate.

Preferably, the size of the first particles of the abrasive is 50 to 300 nm, the size of the second particles is 500 to 1,000 nm, and the second particles having a large particle size preferentially polish the surface to be polished quickly, The first particles having a small size can flatten the polished surface to be polished to thereby exhibit an excellent polishing rate while minimizing the scratch on the polished surface.

The first particles and the second particles may be homogeneous abrasives or different abrasives.

The weight ratio of the first particle and the second particle is preferably 20 to 40: 60 to 80, and when the weight ratio satisfies the above range, the polishing rate can be improved while minimizing scratches.

The size of the crystallite of the abrasive is preferably 1 to 200 nm, and the size of the crystal grains can be measured using an X-ray diffraction spectrometer or a transmission type scanning microscope.

The method of preparing the abrasive is not particularly limited as long as it is a metal oxide particle production method applied in the art, and a solid phase method or a liquid phase method can be used.

Taking cerium oxide as an example, the solid phase method is a method in which raw materials such as cerium carbonate, cerium hydroxide and the like are calcined and oxidized at 600 to 1000 ° C to obtain cerium oxide and then pulverized using wet ball milling or dry ball milling Cerium powder may be prepared, or the cerium hydroxide may be dry-pulverized by ball milling followed by calcination to produce fine cerium oxide powder.

The liquid phase method is produced by reacting cerium nitrate, cerium sulfate or the like in a liquid phase under an appropriate catalyst. Unlike the solid phase method, cerium oxide thus produced generally does not require a milling process by physical milling, and it can maintain the original zeta potential because no separate dispersant is required. The cerium oxide particles produced by the liquid phase method may have a high polishing rate for the oxide film even with a small content.

The abrasive may be used in an amount of 1 to 30% by weight, preferably 5 to 20% by weight, based on 100% by weight of the total slurry composition. When the content of the abrasive is less than 1% by weight, the polishing rate is decreased. When the content is more than 30% by weight, the dispersibility of the composition is low and a large amount of scratches may occur on the surface to be polished.

The polishing assistant is used for improving the dispersion stability and polishing performance of the composition and is characterized by having a pH of 9.5 to 12 at 25 ° C.

In general, as the polishing is continued using the slurry composition, by-products generated in the polishing process are increased, and OH ^- ions existing in the composition are bonded to and replaced with the wafer surface. Thus, the slurry composition will continuously decrease the OH < ^{- &} gt ^; ions and increase the zeta potential value in the composition. Generally, the abrasive particles are negatively charged in the periphery and can be dispersed in a colloidal form without agglomeration in the slurry composition by an appropriate electrostatic repulsive force. However, the increase of the zeta potential decreases the negative charge around the abrasive particles, The probability of cohesion increases. This increases the likelihood of generating defects and scratches on the wafer surface, resulting in poor polishing efficiency.

The polishing assistant of the present invention preferably has a pH of 9.5 to 12 in a solution state at 25 캜 in order to suppress the pH decrease of the slurry composition.

The polishing assistant is preferably a modified maleic acid copolymer, more preferably a structure represented by the following formula (1).

[Chemical Formula 1]

(In the above formula (1), n is 1 to 30 and m is 5 to 1,000.)

Conventional polishing aids have the form of a block copolymer in order to increase the dispersion stability of the abrasive particles and control the stability by adjusting the content ratio of the segments constituting the copolymer. That is, a segment having affinity with the abrasive particles and a segment having affinity with the liquid carrier are polymerized.

When a segment having affinity with an abrasive agent is present on one or both of the ends of the main chain, the molecular weight of the polishing adjuvant is relatively small as compared with other cases, so that the viscosity is low and the abrasive agent is easily dispersed. The polishing assistant tends to be detached from the abrasive even in a small impact, resulting in poor stability.

In addition, in the case of the ABA block copolymer or the random copolymer, the stability is increased due to the high molecular weight as compared with the case where the segment has an affinity for the abrasive at the end of the main chain, and the position and size of the segment having affinity with the liquid carrier The dispersibility of the abrasive varies greatly depending on the temperature and other parameters, interference is applied to the segment having affinity with the liquid carrier, so that the abrasive may easily be desorbed and the stability may be deteriorated.

DISCLOSURE OF THE INVENTION The present invention is directed to solving the disadvantages of such conventional polishing aids in that a segment having affinity with an abrasive is oriented in one direction of the main chain and a segment having affinity with a liquid carrier in another direction is branched So that the polishing assistant has a comb-like form as shown in Formula 1, thereby enhancing the affinity between the abrasive and the liquid carrier.

In the present invention, it is preferable that the polishing assistant has a structure of the following formula (2).

(2)

(In the above formula (2), m is from 20 to 100.)

Since the polishing assistant according to the present invention has the above-described structure, the affinity with the polishing compound is further improved as compared with the conventional polishing assistant having an acrylate segment as a segment having affinity with the polishing compound, and at the same time, The scratches and defects occurring in the semiconductor device can be reduced.

The abrasive aid may be prepared by emulsion polymerization of styrene, maleic anhydride and a solvent by a pre-emulsion addition method. In this case, the polymerization temperature may be 20 to 100 ° C, more preferably 50 to 55 ° C. It is preferable to adjust the pH of the polymerization composition by adding a basic substance such as ammonia when the polymerization reaction proceeds.

When the emulsion polymerization is used as the method of preparing the polishing aid, it is preferable to adjust the amount of ammonia added in the polymerization process to 1 to 20 wt%, more preferably 8 to 15 wt%, of 100 wt% of the whole composition. When the amount of ammonia added is less than 1 wt%, the polymerization of the modified maleic acid copolymer is not proceeded properly. When the amount of ammonia is more than 20 wt%, the pH stability and polishing efficiency of the slurry composition are lowered.

Water is added to the prepared styrene-maleic anhydride copolymer to conduct a ring-opening reaction, whereby a styrene-maleic acid copolymer having two carboxyl groups in the repeating unit can be prepared.

The polishing assistant is preferably contained in an amount of 1 to 30% by weight, more preferably 3 to 15% by weight, based on 100% by weight of the entire slurry composition. When the content of the polishing aid is less than 1% by weight, the dispersion stability is deteriorated. When the content is more than 30% by weight, a large amount of scratches are generated on the surface to be polished and the polishing efficiency is lowered.

The slurry composition may further include a styrene-maleic anhydride copolymer represented by the following formula (3) as a polishing assistant.

(3)

(In the above formula (3), n is 1 to 30 and m is 5 to 1,000.)

The styrene-maleic anhydride copolymer preferably has a structure represented by the following formula (4).

[Chemical Formula 4]

(In the formula (4), m is from 20 to 100.)

When the styrene-maleic acid copolymer and the styrene-maleic anhydride copolymer are used simultaneously as the dispersion auxiliary agent, the weight ratio of the styrene-maleic acid copolymer and the styrene-maleic anhydride copolymer is 60 to 80:20 to 40, .

The liquid carrier is for dispersing the abrasive, and any liquid can be used as long as it can be mixed with the abrasive and the polishing aid to form a dispersion and a slurry state. Suitable liquid carriers are preferably polar solvents, preferably deionized water (deionized water).

In addition, the polishing slurry composition of the present invention may further comprise a pH adjuster to keep the zeta potential constant.

The pH adjusting agent is used to adjust the pH of the polishing slurry composition to a range of 9.5 to 12, and the kind of the pH adjusting agent is not limited within the scope of achieving the object of the present invention. Examples of the solvent include trimethanolamine, triethanolamine, trimethylammonium hydroxide, triethylammonium hydroxide, dimethylbenzylamine, ethoxybenzylamine, amine, sodium hydroxide, and potassium hydroxide, and may contain 0.0001 to 1% by weight based on 100% by weight of the total slurry composition. In this range, the polishing efficiency of the slurry composition is not reduced, and the dispersion stability of the abrasive does not deteriorate.

The slurry composition may be a (meth) acrylic acid polymer or an ammonium salt thereof; Water-soluble organic polymers such as polyvinyl alcohol; Water-soluble anionic surfactants such as ammonium lauryl sulfate and ammonium polyoxyethylene lauryl ether sulfate; A water-soluble nonionic surfactant such as polyoxyethylene lauryl ether, polyethylene glycol monostearate, and the like.

The content of the dispersant is preferably 1 to 10 parts by weight based on 100 parts by weight of the polishing assistant.

Further, the slurry composition according to the present invention may further contain at least one anti-adsorption agent to prevent the abrasive from remaining on the wafer and contaminating the wafer even after polishing. The adsorption inhibitor is not limited to the present invention but may be, for example, 1-butanol, mercaptoethanol, hydroxyethyl methacrylate, N-octyl acrylate, acrylate, fluorescein monoacrylate, tert-butyl acrylate ethylene glycol, trifluoroethyl acrylate, N-hydroxysuccinimidyl methacrylate, N-hydroxysuccinimidyl methacrylate, and methyl methacrylate. Any one or two or more of them may be used in combination.

In the present invention, the adsorption inhibitor is preferably added in an amount of 0.1 to 1% by weight based on 100% by weight of the total slurry composition. When the amount is less than the above range, the effect of preventing the adsorption of the abrasive agent is not properly exhibited. If the amount is exceeded, the abrasion of the wafer may be adversely affected.

The slurry composition according to the present invention may further contain at least one phase change material to prevent a decrease in polishing efficiency due to a temperature change of the slurry composition. The phase change material may be mixed with the adsorption inhibitor to further enhance the adsorption prevention effect of the polishing slurry.

The phase change material should have a melting temperature at the desired temperature and have a high latent heat per unit amount. In addition, there should be a high specific heat for the heat storage and a high thermal conductivity in both solid and liquid state. Here, the characteristics should be maintained even in repeated phase changes.

Examples of such phase change materials include paraffin wax, n-eicosane, n-octadecane, n-triacontane, hexadecane, But are not limited to, hexadecane, nonadecane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, polyethylene glycol, But are not limited to, lauric acid, propyl palmitate, capric acid, isopropyl stearate, butyl stearate, palmitic acid, Myristic acid, vinyl stearic acid, etc. These may be used singly or in combination of two or more kinds. If necessary, the materials may be encapsulated to block mixing with the slurry composition.

In the present invention, it is preferable that the phase-change material is mixed in an amount of 0.1 to 1% by weight based on 100% by weight of the total slurry composition. When the amount is less than the above range, the reduction of the polishing efficiency of the slurry may be conspicuous depending on the temperature change, and if it is added in excess of the above range, the abrasive action of the abrasive agent is disturbed.

In the present invention, the polishing slurry is not limited to the production method. For example, the polishing slurry may be prepared by, for example, 1) firing an abrasive as a raw material to form an oxidized state and then pulverizing the primary raw material, 2) mixing the primary pulverized abrasive with a solvent and a polishing assistant To prepare a slurry. The prepared slurry can be milled using 3) beads.

In the present invention, the step 1) may be performed by heat treatment at a temperature of 600 to 1,200 ° C. for 30 minutes to 6 hours, and the fired abrasive may be primarily fired by a ball milling method, a bead milling method, a jet milling method, Pulverized and pulverized.

In the present invention, the undifferentiated abrasive does not limit the average particle diameter after the primary pulverization but may be, for example, 0.5 to 1.5 탆.

In the present invention, step 2) is a step of preparing slurry by mixing all of the above-mentioned compositions, and mixing can be carried out at the same composition ratio.

In the present invention, the step 3) is a step of performing dispersion by secondary milling in order to make a stable and uniform slurry, and to remove the major particles having an average particle size of 3 μm or more to further increase the dispersion stability.

In the present invention, the milling in the step 3) is performed by adjusting the milling speed in the range of 20 to 120 rpm to apply low energy to the abrasive particles at the time of milling, and using balls having a diameter of 2 to 20 mm, more preferably 5 to 10 mm The milling time is not limited, but it is preferably 1 to 200 hours. It is also preferable that the amount of the abrasive particles in the slurry after the milling is 0.05 to 1 占 퐉.

Also, in order to further increase dispersibility as required, ultrasonic dispersion may be performed in the slurry of step c). The ultrasound dispersion may be a method known to those skilled in the art as a method of dispersing by ultrasonic waves commonly used for particle dispersion, and is not particularly limited in the present invention, but examples thereof include a bath type, a tip type, And continuous type.

In the present invention, the output of the ultrasonic dispersing apparatus may range from 500 to 3,000 W, preferably from 1,500 to 2,000 W. The average particle diameter of the abrasive particles can be maintained at 1 占 퐉 or less under the above conditions. The dispersion time is not limited, but it is preferable to proceed for 1 to 24 hours.

The present invention can polish the surface of a substrate with a slurry composition with a known polishing system.

The substrate may be silicon oxide, silicon nitride, polycrystalline silicon, or the like, and may be formed of borophosphosilicate glass (BPSG), plasma enhanced tetraethylorthosilicate (PETEOS) ), A thermal oxide, a nitrogen doped silicate glass, an undoped silicate glass, and a high density plasma (HDP) oxide, but the present invention is not limited thereto.

In the present invention, the polishing system may be applied to a conventional technique. For example, a wafer is fixed to a polishing system comprising a fiber polishing pad, the wafer is pressed against the polishing pad while controlling pressure, speed and temperature conditions, the pad and wafer are moved relative to each other, The film quality of the wafer can be chemically and mechanically polished.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. The following examples are intended to illustrate the practice of the present invention and are not intended to limit the scope of the present invention.

(Example 1)

62% by weight of water and 8% by weight of ammonia were mixed as a solvent in 30% by weight of a polymer composition prepared by mixing maleic anhydride and styrene at a ratio of 25 mol% and 75 mol%, respectively, To obtain a styrene-maleic anhydride copolymer of n = 3 and m = 100.

Next, 10 parts by weight of water and 0.1 part by weight of dicumyl peroxide were added to 100 parts by weight of the styrene-maleic anhydride copolymer, and the ring-opening reaction was carried out at 185 DEG C for 6 hours under a nitrogen atmosphere to obtain two carboxyl groups Styrene-maleic acid copolymer (SMA).

16 wt% of cerium oxide particles having an average particle size of 100 nm was dispersed in 80 wt% of ultrapure water, and 4 wt% of the styrene-maleic acid copolymer was added and stirred for 2 hours to obtain a polishing slurry composition.

(Example 2)

A polishing slurry composition was obtained in the same manner as in Example 1 except that 15.5 wt% of cerium oxide particles and 4.5 wt% of styrene-maleic acid copolymer were used.

(Example 3)

A polishing slurry composition was obtained in the same manner as in Example 1, except that 15 wt% of cerium oxide particles and 5 wt% of styrene-maleic acid copolymer were used.

(Example 4)

A polishing slurry composition was obtained in the same manner as in Example 1, except that N-octyl acrylate as an adsorption inhibitor was added in an amount of 0.5% by weight based on 100% by weight of the total slurry composition.

(Example 5)

A polishing slurry composition was obtained in the same manner as in Example 1, except that 3 wt% of styrene-maleic acid copolymer and 1 wt% of styrene-maleic anhydride copolymer were used instead of 4 wt% of styrene-maleic acid copolymer.

(Comparative Example 1)

A polishing slurry composition was obtained in the same manner as in Example 1, except that a styrene-acrylate copolymer having a weight average molecular weight of 2,000 g / mol was used instead of the styrene-maleic acid copolymer.

(Subject to polishing)

The wafers used were flat silicon nitride films (NIT), silicon oxide films (PE-TEOS) and polysilicon wafers (Poly). The silicon nitride film wafer is formed by depositing 1000 Å of PE-TEOS on a silicon wafer and then depositing a silicon nitride film of 1800 Å by a chemical vapor deposition method. The silicon oxide wafers were obtained by depositing PE-TEOS to a thickness of 10,000 Å on a silicon wafer. The polysilicon wafer is formed by depositing polysilicon with a thickness of 3000 Å on a silicon wafer.

(CMP process conditions)

The polishing process conditions are shown in Table 1 below.

CMP parameter CMP condition equipment POLI-380 (G & P Teechnology) Abrasive pad IC-1300 (Rodel) Slurry inflow rate 90 ml / min Head speed 60rpm Table speed 40 rpm pressure 3 psi Polishing time 60 seconds

(Size of abrasive particle size)

An appropriate amount of the CMP polishing liquid was put into the container, and the chips with the pattern wiring wafers cut at 2 cm square were immersed in the container for about 30 seconds. Then, the chips were transferred to a container filled with pure water, rinsed for about 30 seconds, and the chips were subjected to nitrogen blow drying. Thereafter, a chip was placed on a sample stand for SEM observation, and an acceleration voltage of 10 kV was applied using a scanning electron microscope (product name: S-4800, manufactured by Hitachi High-Technologies Corporation) A plurality of images were photographed. 20 particles were arbitrarily selected from the obtained images. With respect to each of the collected particles, the biaxial average particle diameter was determined based on the scale shown in the SEM image. The average value of the obtained biaxial average particle diameters was defined as the average particle diameters of the particles.

(Slurry treatment)

The prepared slurry was divided and stored in an oven. At this time, the temperature of the oven was set to 10 ° C. and 60 ° C., respectively, and the storage time was immediately after storage (0 hour) and 2 hours.

(Polishing efficiency)

The thickness of the specimen wafer before and after polishing was confirmed by ADE 9500 and ADE Corp. At this time, nine identical points in the clockwise direction from the center to the edge were measured and averaged for each wafer in order to prevent the measurement error.

(pH stability)

HandyLab pH / LF12, Schott. The slurry was measured immediately after the preparation, at 1 day, 4 days, 5 days, 6 days and 7 days.

(Viscosity stability)

The shear rate was measured in a range of 0 to 120 sec ^-1 using a viscometer (DV-II + Pro Viscometer, Brookfield). The slurry was measured immediately after manufacture, 1 day, 4 days, 5 days, 6 days and 7 days.

(Electrical conductivity stability)

Measured with a thermostatable instrument (Nano ZS, Malvern Instruments Ltd.). The slurry was measured immediately after manufacture, 1 day, 4 days, 5 days, 6 days and 7 days.

(Abrasive particle size stability)

Measured with a thermostatable instrument (Nano ZS, Malvern Instruments Ltd.). The slurry was measured immediately after manufacture, 1 day, 4 days, 5 days, 6 days and 7 days.

(Slurry remaining)

First, a copper wafer (thickness of about 10,000 Å) was immersed in a dilute HF (DHF) solution of 100: 1 for 30 seconds and DIW cleaning was performed for 60 seconds. The washed copper wafer was immersed in the prepared slurry for 20 seconds and again washed with ultrapure water for 60 seconds. After the washed wafer was dried through nitrogen, the surface of the treated wafer was observed at a magnification of 5,000 times using a field emission scanning microscope (PE-SEM), and the number of the remaining slurry was checked and evaluated as follows.

◎: Less than 20

○: 20 or more, less than 30

B: 30 or more, less than 40

X: 40 or more

(Whether scratching)

After polishing, the substrate was cleaned and the substrate was observed for defects and scratches by an optical microscope. The results were excellent, good, normal, and defective.

The physical properties of the polishing slurry compositions obtained from the above Examples and Comparative Examples were measured and shown in the following table.

pH (10 ° C) pH (60 DEG C) 0 hours 2 hours 0 hours 2 hours Example 1 0 days 9.40 9.40 9.40 9.40 1 day 9.61 9.31 9.15 9.26 4 days 9.62 9.38 9.06 9.41 5 days 9.69 9.38 9.04 9.20 6 days 9.64 9.17 9.02 9.23 7 days 9.66 9.26 9.16 9.40 Example 2 0 days 9.40 9.40 9.40 9.40 1 day 9.77 9.32 9.01 9.31 4 days 9.71 9.39 9.07 9.46 5 days 9.69 9.38 9.03 9.41 6 days 9.71 9.17 9.11 9.15 7 days 9.79 9.32 9.23 9.41 Example 3 0 days 9.40 9.40 9.40 9.40 1 day 9.69 9.32 9.01 9.37 4 days 9.62 9.36 9.06 9.43 5 days 9.72 9.38 9.04 9.43 6 days 9.69 9.20 9.12 9.26 7 days 9.71 9.32 9.15 9.41 Comparative Example 1 0 days 9.40 9.40 9.40 9.40 1 day 8.61 8.67 8.64 8.67 4 days 8.64 8.67 8.64 8.64 5 days 8.62 8.64 8.61 8.64 6 days 8.61 8.65 8.62 8.65 7 days 8.61 8.62 8.63 8.61

Conductivity (10 ℃) Conductivity (60 ℃) 0 hours 2 hours 0 hours 2 hours Example 1 0 days 180 180 180 180 1 day 151 173 200 252 4 days 153 200 211 223 5 days 190 197 215 209 6 days 189 191 228 223 7 days 190 201 220 228 Example 2 0 days 180 180 180 180 1 day 205 176 201 199 4 days 205 207 200 234 5 days 203 220 235 250 6 days 203 206 217 242 7 days 202 215 220 261 Example 3 0 days 180 180 180 180 1 day 200 203 203 199 4 days 201 219 202 240 5 days 201 230 209 277 6 days 202 227 257 268 7 days 206 231 260 270 Comparative Example 1 0 days 180 180 180 180 1 day 181 187 183 183 4 days 184 184 184 182 5 days 181 186 184 183 6 days 183 187 183 181 7 days 182 184 181 186

Viscosity (10 ° C) Viscosity (60 ° C) 0 hours 2 hours 0 hours 2 hours Example 1 0 days 1.32 1.32 1.32 1.32 1 day 1.39 1.34 1.33 1.32 4 days 1.42 1.38 1.27 1.35 5 days 1.41 1.37 1.35 1.39 6 days 1.39 1.40 1.31 1.36 7 days 1.41 1.28 1.40 1.40 Example 2 0 days 1.32 1.32 1.32 1.32 1 day 1.39 1.34 1.29 1.32 4 days 1.42 1.35 1.34 1.34 5 days 1.41 1.38 1.26 1.39 6 days 1.42 1.37 1.29 1.37 7 days 1.38 1.38 1.31 1.32 Example 3 0 days 1.32 1.32 1.32 1.32 1 day 1.40 1.34 1.32 1.30 4 days 1.39 1.38 1.25 1.33 5 days 1.39 1.36 1.24 1.34 6 days 1.41 1.35 1.35 1.35 7 days 1.33 1.36 1.29 1.39 Comparative Example 1 0 days 1.32 1.32 1.32 1.32 1 day 1.24 1.25 1.21 1.30 4 days 1.21 1.22 1.22 1.23 5 days 1.21 1.23 1.23 1.21 6 days 1.28 1.25 1.22 1.20 7 days 1.21 1.25 1.21 1.20

Particle size (10 ℃) Particle diameter (60 DEG C) 0 hours 2 hours 0 hours 2 hours Example 1 0 days 205 210 210 210 1 day 240 241 241 240 4 days 240 253 253 251 5 days 236 211 204 224 6 days 238 207 202 227 7 days 240 243 242 248 Example 2 0 days 253 251 250 250 1 day 245 258 212 237 4 days 258 236 253 261 5 days 211 217 200 238 6 days 205 229 230 221 7 days 287 257 251 246 Example 3 0 days 230 230 246 237 1 day 250 247 264 263 4 days 297 294 264 251 5 days 214 197 207 238 6 days 196 211 200 179 7 days 250 249 240 250 Comparative Example 1 0 days 207 194 197 194 1 day 198 198 194 194 4 days 194 196 193 187 5 days 198 197 194 193 6 days 194 195 196 175 7 days 192 187 192 197

As shown in Tables 2 to 5 and FIGS. 1 to 5, the slurry prepared according to the present invention shows excellent values in terms of pH stability, electrical conductivity stability, viscosity stability, and particle size stability.

On the other hand, in the case of the polishing slurry using the ordinary styrene-acrylate copolymer of the comparative example, the viscosity and the pH stability were poor and the slurry was aggregated in many cases, but the slurry of the example showed stable dispersion even at high temperature.

Ultraviolet transmittance
(%) Electrical conductivity stability
(㎲ / cm) Polishing efficiency
(Å / min) PE-TEOS NIT Poly Example 1 94.0 28.32 4805 1087 1236 Example 2 90.6 28.44 5084 1280 1477 Example 3 91.2 28.25 4913 1151 1207 Comparative Example 1 85.4 23.64 2238 650 853

As shown in Table 6, the slurry prepared according to the present invention showed significantly increased ultraviolet transmittance, electrical conductivity stability and polishing efficiency for the three types of wafers as compared with Comparative Example 1 using the slurry prepared by adding the conventional dispersant as the polishing assistant .

Polishing efficiency Residual slurry Scratch PE-TEOS NIT Poly Example 1 5021 1234 1405 ○ usually Example 4 5084 1280 1437 ○ Good Example 5 5217 1304 1520 ◎ eminence Comparative Example 1 3541 891 1039 × Bad

From the results in Table 2, it can be seen that Examples 1, 4 and 5 increase the polishing efficiency and minimize the occurrence of residual slurry and scratches.

In particular, in Examples 4 and 5, it is understood that the polishing rate and the polishing efficiency are the most excellent, and the occurrence of scratches on the polished surface is minimized.

Claims (4)

a) one or two or more abrasives selected from aluminum oxide, silicon oxide, zirconium oxide and cerium oxide;
b) a polishing aid which binds to the surface of the polishing compound to improve the dispersibility of the polishing compound; And
c) a polishing slurry composition comprising a liquid carrier,
The polishing slurry composition comprises 1 to 30% by weight of an abrasive, 1 to 30% by weight of a polishing aid, and a residual liquid carrier,
The abrasive aid is a styrene-maleic acid copolymer having a structure represented by the following formula (1) and a styrene-maleic anhydride copolymer having a structure represented by the following formula (3)
Wherein the weight ratio of the styrene-maleic acid copolymer and the styrene-maleic anhydride copolymer is 60 to 80:20 to 40.

[Chemical Formula 1]

(In the above formula (1), n is 1 to 30 and m is 5 to 1,000.)

(3)

(In the above formula (3), n is 1 to 30 and m is 5 to 1,000.)
The method according to claim 1,
Wherein the abrasive is cerium oxide.
The method according to claim 1,
The polishing slurry composition further comprises at least one pH adjusting agent selected from trimethanolamine, triethanolamine, trimethylammonium hydroxide, triethylammonium hydroxide, dimethylbenzylamine, ethoxybenzylamine, sodium hydroxide, and potassium hydroxide By weight of the polishing slurry composition.
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