JP2001002415A - Cmp polishing agent and method for polishing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CMP(chemical mechanical polishing) polishing agent which is capable of effecting advanced surface planarization and polishing a surface to be polished, such as surface of a silicon oxide insulation film, at a high rate without causing any flaws in the surface by using as the components of the agent, cerium oxide grains, a dispersant, an additive selected from polyacrylamide and its derivatives, and water. SOLUTION: This CMP polishing agent has a composition consisting of cerium oxide grains, a dispersant, an additive selected from polyacrylamide and its derivatives, and water, or alternatively, a composition consisting of a cerium oxide slurry that contains cerium oxide grains, dispersant and water, and an additive liquid that contains an additive and water. This polishing method comprises: pushing a substrate provided with a film to be polished, which film is formed on the surface of a substrate base material, against a polishing cloth of a polishing turntable; then applying a pressure to the substrate; and in that state, moving the substrate and turntable while supplying the CMP polishing agent to between the film to be polished and the polishing cloth, to polish the film to be polished; wherein preferably, the crystallite size of the cerium oxide used is 5-300 nm and desirably, the total content of alkali metals, halogens and sulfur in the cerium oxide grains is controlled so as to be <=10 ppm.

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 device manufacturing technology, in particular, a flattening process of an interlayer insulating film, a forming process of shallow trench isolation, 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 At present, ultra-large-scale integrated circuits tend to increase the packing density, and various microfabrication techniques have been studied and developed. Already, design rules are on the order of sub-half microns. One of the technologies that have been developed to satisfy such strict requirements for miniaturization is a CMP (Chemical Mechanical Polishing) technology. This technology completely flattens the layer to be exposed in the semiconductor device manufacturing process, reducing the burden of the exposure technology,
Since the yield can be stabilized, the technique is indispensable when performing, for example, planarization of an interlayer insulating film, isolation of a shallow trench, and the like. Conventionally, in a semiconductor device manufacturing process, plasma-CVD (Chemical Vapor Depositio
n, chemical vapor deposition), C for planarizing an inorganic insulating film layer such as a silicon oxide insulating film formed by a method such as low pressure-CVD.
Fumed silica-based abrasives have been generally studied as MP abrasives. Fumed silica abrasives
The silica particles are produced by growing particles by a method such as thermal decomposition of tetrachlorosilicic acid and adjusting the pH. However,
Such an abrasive does not have a sufficient polishing rate for the inorganic insulating film, and there has been a technical problem of a low polishing rate for practical use. In the conventional CMP technique for planarizing an interlayer insulating film, the polishing rate greatly depends on the pattern of a film to be polished on a substrate, and the polishing rate of a convex portion differs greatly depending on the pattern density difference or the size difference. Therefore, there has been a technical problem that high-level planarization over the entire surface of the wafer cannot be realized. Further, in the CMP technique for flattening an interlayer film, it is necessary to end polishing in the middle of the interlayer film, and a process management method of controlling a polishing amount by a polishing time is generally performed. However, there has been a problem that not only the change in the pattern step shape but also the state of the polishing cloth significantly changes the polishing rate, making process management difficult. In the generation of the design rule of 0.5 μm or more, LOCOS (local oxidation of silicon) has been used for element isolation in an integrated circuit. After that, when the processing size becomes finer, the technology of narrow element isolation width is required,
Shallow trench isolation is being used. In the shallow trench isolation, CMP is used to remove an excess silicon oxide film formed on the substrate, and a stopper film having a low polishing rate is formed below the silicon oxide film to stop polishing. Silicon nitride or the like is used for the stopper film, and it is desirable that the polishing rate ratio between the silicon oxide film and the stopper film is large.

On the other hand, cerium oxide abrasives have been used as abrasives for glass surfaces such as photomasks and lenses. Cerium oxide particles have a lower hardness than silica particles and alumina particles and are therefore less likely to scratch the polished surface, and thus are useful for finish mirror polishing. However, since a cerium oxide abrasive for polishing a glass surface uses a dispersant containing a sodium salt, it cannot be directly used as an abrasive for semiconductors.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a CMP polishing agent which can be highly planarized and can be polished at high speed without damaging the surface to be polished such as a silicon oxide insulating film. It is intended to provide a CMP polishing agent having improved. The present invention also provides a substrate polishing method capable of polishing a surface to be polished of a substrate without flaws.

[0005]

The CMP polishing slurry of the present invention contains cerium oxide particles, a dispersant, an additive selected from polyacrylamide and its derivatives, and water. The CMP polishing slurry of the present invention can be composed of a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and an additive solution containing an additive and water. In the polishing method of the present invention, the substrate on which the film to be polished is formed is pressed against a polishing cloth of a polishing platen and pressurized. The board is moved to polish the film to be polished.

[0006]

DETAILED DESCRIPTION OF THE INVENTION Generally, cerium oxide is a carbonate,
It is obtained by oxidizing cerium compounds of nitrates, sulfates and oxalates. A cerium oxide abrasive used for polishing a silicon oxide film formed by a TEOS-CVD method or the like can perform high-speed polishing as the primary particle diameter is larger and the crystal distortion is smaller, that is, the crystallinity is better. Polishing scratches tend to occur. Therefore, the cerium oxide particles used in the present invention are not limited to a method for producing the cerium oxide particles.
It is preferably 0 nm or less. Further, since it is used for polishing a semiconductor chip, the content of alkali metals and halogens is preferably suppressed to 10 ppm or less in the cerium oxide particles.

In the present invention, as a method for producing cerium oxide powder, calcination or an oxidation method using hydrogen peroxide or the like can be used. The firing temperature is preferably from 350 ° C. to 900 ° C. Since the cerium oxide particles produced by the above method are agglomerated, it is preferable to mechanically pulverize the particles. As the pulverization method, a dry pulverization method using a jet mill or the like or a wet pulverization method using a planetary bead mill or the like is preferable. The jet mill is described in, for example, Chemical Industry Transactions, Vol. 6, No. 5 (198
0) pages 527-532.

[0008] The CMP abrasive in the present invention is, for example,
It is obtained by dispersing a composition comprising cerium oxide particles having the above characteristics, a dispersant, and water, and further adding an additive. Here, the concentration of the cerium oxide particles is not limited, but is 0.5% by weight from the viewpoint of easy handling of the dispersion.
The range is preferably not less than 20% by weight and not more than 20% by weight. In addition, since it is used as a dispersant for polishing semiconductor chips, the content of alkali metals such as sodium ions and potassium ions, halogens, and sulfur is preferably suppressed to 10 ppm or less. For example, ammonium acrylate as a copolymerization component A polymer dispersant containing is preferred. Also, a polymer dispersant containing ammonium acrylate as a copolymer component and a water-soluble anionic dispersant, a water-soluble nonionic dispersant,
Two or more dispersants including at least one selected from a water-soluble cationic dispersant and a water-soluble amphoteric dispersant may be used. As the water-soluble anionic dispersant, for example,
Triethanolamine lauryl sulfate, ammonium lauryl sulfate, polyoxyethylene alkyl ether triethanolamine sulfate, special polycarboxylic acid type polymer dispersants, and the like.Examples of water-soluble nonionic dispersants include polyoxyethylene lauryl ether. , Polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether,
Polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxy Ethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbite tetraoleate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene Glycol distearate, polyethylene glycol monooleate, poly Carboxymethyl ethylene alkyl amines, polyoxyethylene hardened castor oil, and alkyl alkanolamide. Examples of the water-soluble cationic dispersant,
For example, polyvinylpyrrolidone, coconutamine acetate, stearylamine acetate and the like, and as the water-soluble amphoteric dispersant, for example, lauryl betaine,
Examples include stearyl betaine, lauryl dimethylamine oxide, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine.
These dispersing agents are added in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the cerium oxide particles from the relationship between the dispersibility of the particles in the slurry and the prevention of sedimentation, and the relationship between the polishing scratches and the amount of the dispersing agent added. A range of not more than parts by weight is preferred. The molecular weight of the dispersant is preferably from 100 to 50,000, and preferably 1,000 to 50,000.
-10,000 is more preferable. When the molecular weight of the dispersant is 10
If it is less than 0, a sufficient polishing rate cannot be obtained when polishing a silicon oxide film or a silicon nitride film, and if the molecular weight of the dispersant exceeds 50,000, the viscosity becomes high and C
This is because the storage stability of the MP abrasive decreases. As a method of 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 dispersion treatment using an ordinary stirrer.
The average particle size of the cerium oxide particles in the CMP polishing slurry thus produced is preferably 0.01 μm to 1.0 μm. Average particle size of cerium oxide particles is 0.01 μm
If it is less than 1.0 μm, the polishing rate becomes too low, and if it exceeds 1.0 μm, the film to be polished is easily damaged.

Further, polyacrylamide and its derivatives are preferred as additives. As the polyacrylamide derivative, a polyacrylamide partial hydrolyzate or the like is preferably used. The additive amount of the additive is 0.1 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of cerium oxide particles from the relationship between the dispersibility of the particles in the CMP abrasive and the prevention of sedimentation, and the relationship between the polishing scratches and the additive amount. Parts or less are preferred. If the amount is too small, the effect of adding the additive cannot be obtained, and if the amount is too large, the polishing rate is reduced. The molecular weight of polyacrylamide is preferably 10,000 or more. If the molecular weight is too low, flattening characteristics cannot be obtained.

When a cerium oxide slurry containing cerium oxide particles, a dispersant, and water and an additive solution containing an additive and water are stored as a separate CMP abrasive, the cerium oxide particles do not agglomerate, thereby increasing the storage stability. This is preferable because it can prevent generation of polishing scratches and stabilize the polishing rate. When polishing a substrate with the above-mentioned CMP abrasive, the additive liquid is supplied separately to the polishing platen and the cerium oxide slurry, and mixed on the polishing platen, or mixed with the cerium oxide slurry immediately before polishing. The method of supplying on a surface plate is taken.

As the CMP polishing slurry of the present invention, the above-mentioned CMP polishing slurry may be used as it is, but ammonia, N, N-
Additives such as diethylethanolamine, N, N-dimethylethanolamine, aminoethylethanolamine, and ammonium salts of polyacrylic acid and its derivatives can be added to make a CMP polishing agent.

As a method of forming an inorganic insulating film using the CMP polishing slurry of the present invention, low pressure CVD, plasma CVD, etc.
And the like. In forming a silicon oxide film by low-pressure CVD, monosilane: SiH _{4 is} used as a Si source, and oxygen: O ₂ is used as an oxygen source. This is obtained by performing the SiH ₄ —O ₂ -based oxidation reaction at a low temperature of 400 ° C. or less. In some cases, heat treatment is performed at a temperature of 1000 ° C. or lower after CVD. When doping phosphorus: P for planarizing the surface by high temperature reflow, SiH ₄ —O
It is preferred to use ₂ -PH ₃ system reaction gas. The plasma CVD method has an advantage that a chemical reaction requiring a high temperature can be performed at a low temperature under normal thermal equilibrium. The plasma generation method includes two types, a capacitive coupling type and an inductive coupling type. As a reaction gas, SiH ₄ is used as a Si source, and N 2 is used as an oxygen source.
₂ O The SiH ₄ -N ₂ O-based gas and TEOS-O ₂ based gas of tetraethoxysilane (TEOS) was used in the Si source used (TEOS-plasma CVD method). The substrate temperature is 250 ° C to 400 ° C, and the reaction pressure is 67 to 400.
The range of Pa is preferable. As described above, the silicon oxide film of the present invention may be doped with elements such as phosphorus and boron. Similarly, silicon nitride film formation by low pressure CVD
Dichlorosilane: SiH ₂ Cl ₂ is used as an i source, and ammonia: NH ₃ is used as a nitrogen source. This SiH ₂ Cl ₂
It can be obtained by performing an -NH ₃ -based oxidation reaction at a high temperature of 900 ° C. In the plasma CVD method, a SiH ₄ —NH ₃ gas using SiH ₄ as a Si source and NH ₃ as a nitrogen source is used as a reaction gas. Substrate temperature is 3
00 ° C to 400 ° C is preferred.

As a substrate, a silicon oxide film layer or a silicon nitride film layer is formed on a semiconductor substrate such as a semiconductor substrate in which circuit elements and wiring patterns are formed, and a semiconductor substrate in which circuit elements are formed. Substrate can be used. By polishing the silicon oxide film layer or the silicon nitride film layer formed on such a semiconductor substrate with the above-mentioned CMP polishing agent, the unevenness on the surface of the silicon oxide film layer is eliminated,
A smooth surface can be provided over the entire surface of the semiconductor substrate. It can also be used for shallow trench isolation. For use in shallow trench isolation, it is necessary that the ratio of the polishing rate of the silicon oxide film to the polishing rate of the silicon nitride film and the polishing rate of the silicon oxide film / the polishing rate of the silicon nitride film be 10 or more. If the ratio is less than 10, the difference between the polishing rate of the silicon oxide film and the polishing rate of the silicon nitride film is small, and it becomes impossible to stop polishing at a predetermined position when performing shallow trench isolation. When this ratio is 10 or more, the polishing rate of the silicon nitride film is further reduced, and the polishing can be easily stopped, which is more suitable for shallow trench isolation. In addition, in order to use it for shallow trench isolation, it is necessary that the generation of scratches during polishing be small. Here, as a polishing apparatus, a general polishing apparatus having a holder for holding a semiconductor substrate and a platen on which a polishing cloth (pad) is attached (a motor or the like capable of changing the number of rotations is attached) is used. it can. As the polishing cloth, general nonwoven fabric, foamed polyurethane, porous fluororesin and the like can be used, and there is no particular limitation. Further, it is preferable that the polishing cloth is subjected to a groove processing for accumulating a CMP abrasive. The polishing conditions are not limited, but the rotation speed of the surface plate is preferably 200 rpm or less so that the semiconductor substrate does not jump out, and the pressure applied to the semiconductor substrate is 1 kg / kg so as not to cause scratches after polishing.
cm ² or less is preferred. During polishing, the slurry is continuously supplied to the polishing cloth by a pump or the like. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the slurry.

After the polishing is completed, the semiconductor substrate is preferably washed well in running water, and then dried using a spin drier or the like to remove water droplets adhering to the semiconductor substrate. After forming the shallow trench thus flattened, an aluminum wiring is formed on the silicon oxide insulating film layer, and a silicon oxide insulating film is formed again between the wirings and on the wiring by the above method. By polishing using the above-mentioned CMP polishing agent, irregularities on the surface of the insulating film are eliminated, and a smooth surface is formed over the entire surface of the semiconductor substrate. By repeating this process a predetermined number of times, a semiconductor having a desired number of layers is manufactured.

In order to achieve global flattening, it is necessary that an additive is adsorbed on the surface of the silicon oxide film to form a film. The additive film formed on the silicon oxide film inhibits the action of the cerium oxide particles on the surface of the film to be polished, and as a result, reduces the polishing rate. On the other hand, at a high polishing load, the cerium oxide particles break through the additive film and the polishing rate increases. If the film to be polished (silicon oxide film) has irregularities,
Since the effective polishing load of the convex portion is larger than that of the concave portion, the convex portion is selectively polished, and global flattening with little pattern dependency can be achieved. Here, the charges on the surfaces of the silicon oxide film and the silicon nitride film greatly depend on pH, and
When an ionic additive is used, the degree of ionization greatly depends on the pH. Therefore, strict pH control is often required for the ionic additive and the film to be polished to be adsorbed. However, since the polyacrylamide additive of the present invention is nonionic, it physically adsorbs hydrophobically to the film to be polished,
A constant polishing rate independent of H can be expected, and there is an advantage that strict pH control is not required.

In addition, when an additive, which is an electrolyte, is mixed with a slurry, if a large amount of the additive is used, particles precipitate due to salting out, and there is a problem in storage stability. Since the polyacrylamide additive of the present invention is nonionic, it has a feature of being excellent in storage stability.

The CMP polishing slurry of the present invention can be used not only for a silicon oxide film formed on a semiconductor substrate, but also for a silicon oxide film formed on a wiring board having predetermined wiring, an inorganic insulating film such as glass and silicon nitride, and a polycrystalline silicon oxide. Silicon, Al, Cu, Ti, TiN,
A film mainly containing W, Ta, TaN, etc .; an optical glass such as a photomask / lens / prism; an inorganic conductive film such as ITO; an optical integrated circuit / optical switching element / optical waveguide composed of glass and a crystalline material; Optical fiber end face, optical single crystal such as scintillator, solid-state laser single crystal, sapphire substrate for blue laser LED, SiC, Ga
A semiconductor single crystal such as P or GaAs, a glass substrate for a magnetic disk, a magnetic head, or the like can be polished.

[0018]

EXAMPLES Example 1 (Preparation of cerium oxide particles) 2 kg of cerium carbonate hydrate
Was placed in a platinum container, and calcined at 800 ° C. for 2 hours in the air to obtain about 1 kg of a yellowish white powder. When this powder was subjected to phase identification by an X-ray diffraction method, it was confirmed that the powder was cerium oxide. The particle diameter of the calcined powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle diameter of cerium oxide surrounded by the grain boundaries was measured, the median of the volume distribution was 190 nm and the maximum was 500 nm. 1 kg of cerium oxide powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to the small particles having the same size as the primary particle diameter, large pulverized residual particles of 1 to 3 μm and 0.5 to 1
Residual particles of μm were mixed.

(Preparation of Cerium Oxide Slurry) 1 kg of the cerium oxide particles prepared above, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight), and 8977 of deionized water
g was mixed and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered through a 1-micron filter, and further 5% by weight of slurry was obtained by adding deionized water. The slurry pH was 8.3. In order to measure the slurry particles with a laser diffraction type particle size distribution analyzer, the slurry particles were diluted to an appropriate concentration and measured.
It was 0 nm. 600 g of the above cerium oxide slurry (solid content: 5% by weight) and a molecular weight of 900 as an additive,
36 g of polyacrylamide and 236 deionized water
4 g were mixed to prepare a cerium oxide abrasive (solid content: 1% by weight) to which a surfactant was added. The abrasive pH
Was 6.5. Further, in order to measure the particles in the abrasive with a laser diffraction particle size distribution analyzer, the particles were diluted to an appropriate concentration and measured. As a result, the median value of the particle diameter was 190 nm.

(Polishing of insulating film layer) Line / Space width is 0.05 to 5 mm and height is 100
After forming a 0 nm Al wiring line part, TEO
A patterned wafer having a silicon oxide film formed to a thickness of 2000 nm by S-plasma CVD is manufactured. The pattern wafer was set on a holder to which a suction pad for attaching a substrate to be held was attached, and the holder was placed with the insulating film face down on a φ600 mm platen to which a polishing pad made of porous urethane resin was attached, Further, the processing load is 300 gf / cm ²
Set to. While dropping the cerium oxide abrasive (solid content: 1% by weight) at a rate of 200 cc / min on the platen, the platen and the wafer were rotated at 50 rpm for 2 minutes,
The insulating film was polished. The polished wafer was thoroughly washed with pure water and then dried. Similarly, polishing time is 3 minutes, 4 minutes, 5 minutes,
The pattern wafer was polished for 6 minutes. Using a light interference type film thickness measurement device, measure the film thickness difference before and after polishing,
The polishing rate was calculated. Line / polishing rate of the Line portion of Space width 1 mm R ₁ and Line / polishing rate of the Line portion of Space width 3 mm R _3, and Line / Space polishing rate ratio of the polishing speed R ₅ of the Line portion of width 5 mm R ₅ / R ₁ and R ₃ / R
_{In No. 1} , the value increased with the polishing time during the polishing time of 2 to 4 minutes, and was substantially constant during the polishing time of 4 to 6 minutes.
Polishing time when the pattern width dependence of the polishing rate became constant 4
For minutes, the polishing rate R ₁ of the Line portion of Line / Space Width 1mm is 344 nm / min (amount of polishing 1377nm), Line /
Polishing rate R ₃ of the Line portion of Space width 3mm is 335nm
/ Min (polishing amount 1338nm), Line / Space width 5mm
Polishing rate R ₅ of the Line portion 315 nm / min (amount of polishing 12
59 nm), and the polishing rate ratios R ₅ / R ₁ and R ₃ / R
₁ was 0.91 and 0.97, respectively. Also,
Line of each Line / Space width when polishing time is 5 minutes and 6 minutes
The polishing amount of the portion was almost the same as that in the case of 4 minutes, and it was found that the polishing hardly progressed after 4 minutes.

Comparative Example 1 (Preparation of cerium oxide particles) 2 kg of cerium carbonate hydrate
Was placed in a platinum container, and calcined at 800 ° C. for 2 hours in the air to obtain about 1 kg of a yellowish white powder. When this powder was subjected to phase identification by an X-ray diffraction method, it was confirmed that the powder was cerium oxide. The particle diameter of the calcined powder was 30 to 100 μm. When the surface of the fired powder particles was observed with a scanning electron microscope, grain boundaries of cerium oxide were observed. When the primary particle diameter of cerium oxide surrounded by the grain boundaries was measured, the median of the volume distribution was 190 nm and the maximum was 500 nm. 1 kg of cerium oxide powder was dry-ground using a jet mill. Observation of the pulverized particles with a scanning electron microscope revealed that, in addition to the small particles having the same size as the primary particle diameter, large pulverized residual particles of 1 to 3 μm and 0.5 to 1
Residual particles of μm were mixed.

(Preparation of cerium oxide slurry) 1 kg of the cerium oxide particles prepared above, 23 g of an aqueous solution of ammonium polyacrylate (40% by weight), and deionized water 8977
g was mixed and subjected to ultrasonic dispersion for 10 minutes while stirring. The obtained slurry was filtered through a 1-micron filter, and 5% by weight of an abrasive was obtained by adding deionized water. The slurry pH was 8.3. 600 g of the above cerium oxide slurry (solid content: 5% by weight) and 2400 g of deionized water were mixed to prepare a cerium oxide abrasive (solid content: 1% by weight). The pH of the abrasive is 7.4
In addition, in order to measure the particles in the abrasive with a laser diffraction type particle size distribution analyzer, the particles were diluted to an appropriate concentration and measured. As a result, the median value of the particle diameter was 190 nm.

(Polishing of insulating film layer) Line / Space width is 0.05 to 5 mm and height is 100
After forming a line portion of 0 nm Al wiring, TE
A pattern wafer in which a silicon oxide film is formed to a thickness of 2000 nm by an OS-plasma CVD method is manufactured. The pattern wafer was set on a holder to which a suction pad for attaching a substrate to be held was attached, and the holder was placed with the insulating film face down on a φ600 mm platen to which a polishing pad made of porous urethane resin was attached, Further processing load is 300g / cm ²
Set to. While the cerium oxide slurry (solid content: 1% by weight) was dropped at a rate of 200 cc / min on the platen, the platen and the wafer were rotated at 50 rpm for 1 minute to polish the insulating film. The polished wafer was thoroughly washed with pure water and then dried. Similarly, the polishing of the pattern wafer was performed with a polishing time of 1.5 minutes and 2 minutes. Line / Space
Polishing rate of the Line portion of width 1 mm R ₁ and Line / Space Width 3
Polishing speed R ₃ of Line part of mm and Line / Space width 5
polishing rate ratio between the polishing rate R ₅ of the Line portion of mm R ₅ / R
₁ and R ₃ / R ₁ were almost constant during the polishing time of 1 to 2 minutes. When the polishing time is 1.5 minutes in which the pattern width dependence of the polishing rate is constant depending on the polishing time, Line / Spac
e polishing rate R ₁ of the Line portion of the width 1mm is 811 nm / min (amount of polishing 1216nm), Line / Space Width 3mm of Line
The polishing rate R _{3 of the} portion is 616 nm / min (the polishing amount is 924 n
m), Line / Space Polishing rate R _{5 of} a line part with a width of 5 mm
Was 497 nm / min (polishing amount: 746 nm), and the polishing rate ratios R ₅ / R ₁ and R ₃ / R ₁ were 0.61 and 0.76, respectively. With a polishing time of 2 minutes, Line / Space
In the Line portion having a width of 0.05 to 1 mm, the polishing reached the Al wiring underlying the silicon oxide film.

Comparative Example 2 (Polishing of insulating film layer) Line / Sp
ace Al with width of 0.05-5mm and height of 1000nm
After forming the line portion of the wiring, a patterned wafer having a 2000 nm-thick silicon oxide film formed thereon by TEOS-plasma CVD is manufactured. Polishing was performed for 2 minutes using a commercially available silica slurry in the same manner as in the example. The p of this commercial slurry
H is 10.3 and contains 12.5 wt% of SiO ₂ particles. The polishing conditions are the same as in the embodiment. Similarly, the pattern wafer was polished by setting the polishing time to 3 minutes, 4 minutes, 5 minutes, and 6 minutes. The difference in film thickness before and after polishing was measured using an optical interference type film thickness measuring device, and the polishing rate was calculated. Polishing rate R ₁ of the Line portion of Line / Space Width 1mm
Line / Space Polishing rate R ₃ of 3 mm wide Line portion, and
Line / polishing rate ratio between the polishing rate R ₅ of the Line portion of Space width 5 mm R ₅ / R ₁ and R ₃ / R _1, the polishing time 2-5
During the minute, the value increased with the polishing time, and was substantially constant in the polishing time of 5 to 6 minutes. If the polishing time is 5 minutes when the dependence of the polishing rate on the pattern width is constant, Line / Sp
polishing rate R ₁ of the Line portion of ace width 1mm is 283 nm /
Min (polishing amount 1416nm), Line / Space 3mm width Li
The polishing rate R ₃ of the ne portion is 218 nm / min (polishing amount 109
2 nm), the polishing rate R ₅ of the Line portion of Line / Space Width 5mm is 169 nm / min (amount of polishing 846 nm), the polishing rate ratio R ₅ / R ₁ and R ₃ / R ₁ are each 0.6
0 and 0.77. When the polishing time is 6 minutes, the polishing rate at the line portion of each Line / Space width is almost the same as that at 5 minutes, and after the polishing rate dependence becomes constant, the polishing rate remains the same. It was found that the polishing proceeded.

[0025]

The CMP polishing slurry of the present invention can be highly planarized, can polish a surface to be polished such as a silicon oxide insulating film at high speed, and has excellent storage stability. In addition, by the polishing method of the present invention, the surface to be polished of the substrate, without scratches,
Polishing becomes possible.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Yoshida 48 Wadai, Tsukuba, Ibaraki Prefecture Within Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd. 4G076 AA02 AA24 AA26 AB09 BA22 BA39 BA46 BC08 BD01 CA05 CA15 CA26 DA30 4J037 AA08 CB16 CC16 DD24 EE08 EE28 EE43 FF18 FF23

Claims (3)

[Claims] 1. A CMP polishing slurry containing cerium oxide particles, a dispersant, an additive selected from polyacrylamide and its derivatives, and water. 2. The CMP polishing slurry according to claim 1, comprising a cerium oxide slurry containing cerium oxide particles, a dispersant and water, and an additive liquid containing an additive and water. 3. A substrate on which a film to be polished is formed is pressed against a polishing cloth of a polishing platen and pressurized, and the CMP polishing agent according to claim 1 or 2 is supplied between the polishing film and the polishing cloth. A substrate polishing method for polishing a film to be polished by moving a polishing platen.