JP2002012857A - Roll-off reducing agent - Google Patents

Abstract

(57) A roll-off reducing agent capable of reducing the roll-off of a substrate to be polished caused by polishing and improving the polishing rate, a roll-off reducing agent composition containing the roll-off reducing agent, A method for reducing the roll-off of a substrate to be polished using a roll-off reducing agent, and a method for manufacturing a substrate to be polished using the roll-off reducing agent. The OH group or the SH group has 2 to 20 carbon atoms.
A carboxylic acid, a monocarboxylic acid having 1 to 20 carbon atoms, a dicarboxylic acid having 2 to 3 carbon atoms and a roll-off reducing agent selected from the group consisting of salts thereof, containing the roll-off reducing agent, an abrasive and water. A roll-off reducing agent composition, a method of reducing the roll-off of a substrate to be polished using the roll-off reducing agent, and a method of manufacturing a substrate to be polished using the roll-off reducing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a roll-off reducing agent. Further, the present invention relates to a roll-off reducing agent composition containing the roll-off reducing agent, a method of reducing roll-off of a substrate to be polished using the roll-off reducing agent, and a method of manufacturing a substrate to be polished using the roll-off reducing agent. .

[0002]

2. Description of the Related Art A demand for a technology for further increasing the capacity of a hard disk is increasing year by year. As a promising means for increasing the capacity of the hard disk, means for manufacturing a substrate capable of reducing the roll-off (driving of the end face of the substrate) generated in the polishing step and recording the outer peripheral portion more is considered. Mechanical polishing conditions that can reduce roll-off, such as hardening and reducing the polishing load, have been studied. However, these mechanical polishing conditions for reducing the roll-off are effective to some extent, but are still insufficient.

As a polishing composition capable of reducing roll-off, a composition comprising water, α-alumina particles and aluminum nitrate is known (Japanese Patent Application Laid-Open No. 9-286975). At present, the roll-off reduction effect cannot be said to be sufficient, and a polishing liquid component excellent in the roll-off reduction effect has not yet been sufficiently studied.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a roll-off reducing agent capable of reducing the roll-off of a substrate to be polished during polishing and improving the polishing rate, and a roll-off reducing agent containing the roll-off reducing agent. An object of the present invention is to provide a composition, a method for reducing roll-off of a substrate to be polished using the roll-off reducing agent, and a method for producing a substrate to be polished using the roll-off reducing agent. In the present specification, the term “roll-off” refers to an end face droop generated on a substrate to be polished during polishing.

[0005]

That is, the gist of the present invention is as follows.
[1] A carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group, a monocarboxylic acid having 1 to 20 carbon atoms, and having 2 to 2 carbon atoms
3, a roll-off reducing agent selected from the group consisting of dicarboxylic acids and salts thereof, [2] a carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group, a monocarboxylic acid having 1 to 20 carbon atoms, A method of reducing roll-off of a substrate to be polished by using one or more roll-off reducing agents selected from the group consisting of 2-3 dicarboxylic acids and salts thereof, and [3] OH group or SH group. Carboxylic acid having 2 to 20 carbon atoms, monocarboxylic acid having 1 to 20 carbon atoms, 2 carbon atoms
The present invention also relates to a method for producing a substrate to be polished using at least one roll-off reducing agent selected from the group consisting of dicarboxylic acids 3 to 3 and salts thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The roll-off reducing agent used in the present invention is a carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group, a monocarboxylic acid having 1 to 20 carbon atoms, and 2 carbon atoms.
And at least one compound selected from the group consisting of dicarboxylic acids and salts thereof.

C 2-20 having an OH or SH group
Examples of the carboxylic acid include oxycarboxylic acid and compounds in which the oxygen atom of the OH group of the acid is replaced with a sulfur atom. From the viewpoint of solubility in water, the number of carbon atoms of these carboxylic acids is 2 to 20, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 6. From the viewpoint of reducing roll-off, the oxycarboxylic acid preferably has a hydroxyl group at the α-position of the carboxyl group.

The number of carbon atoms of the monocarboxylic acid is 1 to 20, preferably 1 to 12, more preferably 1 to 8, and further preferably 1 to 6, from the viewpoint of solubility in water. .

The dicarboxylic acids are those having 2 to 3 carbon atoms, that is, oxalic acid and malonic acid, from the viewpoint of reducing roll-off. Among these roll-off reducing agents, oxycarboxylic acids are preferred from the viewpoint of improving the polishing rate. Further, from the viewpoint of reducing roll-off, dicarboxylic acids are preferred.

2 to 20 carbon atoms having an OH or SH group
Specific examples of the carboxylic acid include glycolic acid, mercaptosuccinic acid, thioglycolic acid, lactic acid, β-hydroxypropionic acid, malic acid, tartaric acid, citric acid, isocitric acid, allocitric acid, gluconic acid, glyoxylic acid,
Glyceric acid, mandelic acid, tropic acid, benzylic acid, salicylic acid and the like can be mentioned. Specific examples of monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, 2-methylhexanoic acid, octanoic acid, 2-ethylhexanoic acid, and nonane Acids, decanoic acid, lauric acid and the like. Among these, acetic acid, oxalic acid, malonic acid, glycolic acid, lactic acid,
Malic acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid are preferred, more preferably oxalic acid, malonic acid, glycolic acid, lactic acid, malic acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid, and particularly preferably. Oxalic, malonic, glycolic, tartaric and glyoxylic acids.

Further, oxalic acid, malic acid, tartaric acid, citric acid and gluconic acid can be used alone or in combination with another roll-off reducing agent to further reduce the clogging of abrasive grains and polishing residues on the polishing pad. This is preferable because it is possible to prevent polishing characteristics such as polishing rate and surface quality from deteriorating due to long-term use of the polishing pad. Further, frequent pad cleaning is not required, that is, the interval between pad dressings can be greatly extended, and productivity is improved, which is excellent in terms of economy, and is therefore preferable. Among them, oxalic acid, tartaric acid and citric acid are preferable, and citric acid is particularly preferable. In addition,
The monocarboxylic acid and dicarboxylic acid used in the present invention are selected from carboxylic acids having no OH group or SH group.

Also, salts of these acids (ie, salts of carboxylic acids having 2 to 20 carbon atoms having an OH or SH group, salts of monocarboxylic acids having 1 to 20 carbon atoms, dicarboxylic acids having 2 to 3 carbon atoms) The acid salt is not particularly limited, and specific examples thereof include salts with metals, ammonium, alkylammonium, organic amines, and the like. Specific examples of metals include
Periodic table (long period type) 1A, 1B, 2A, 2B, 3A,
Metals belonging to groups 3B, 4A, 6A, 7A or 8 are mentioned. Among these metals, metals belonging to groups 1A, 3A, 3B, 7A or 8 are preferable from the viewpoint of roll-off reduction, metals belonging to groups 1A, 3A or 3B are more preferable, and sodium and potassium belonging to group 1A are most preferable. preferable.

Specific examples of the alkyl ammonium include:
Examples include tetramethylammonium, tetraethylammonium, and tetrabutylammonium.

Specific examples of the organic amine include dimethylamine, trimethylamine, and alkanolamine.

Among these salts, ammonium salts, sodium salts and potassium salts are particularly preferred.

The roll-off reducing agent of the present invention can be used by mixing it with a polishing liquid containing an abrasive, water and the like. The polishing composition thus obtained is particularly referred to herein as a “roll-off reducing agent composition”.
That is, the roll-off reducing agent composition of the present invention contains the above-mentioned roll-off reducing agent, an abrasive and water.

[0017] The content of the roll-off reducing agent in the roll-off reducing agent composition is preferably 0.01% by weight or more from the viewpoint of reducing roll-off and improving the polishing rate. From the perspective of improving quality,
It is preferably at most 5% by weight. It is more preferably 0.01 to 3% by weight, further preferably 0.01 to 2% by weight, and most preferably 0.02 to 1% by weight. In addition, the roll-off reducing agent can be used alone or in combination of two or more.

As the abrasive used in the present invention, an abrasive generally used for polishing can be used. Examples of the abrasive include metal; metal or metalloid carbide,
Nitrides, oxides, borides; diamonds and the like. Metal or metalloid elements are listed in the Periodic Table (Long Period Type)
A, 2B, 3A, 3B, 4A, 4B, 5A, 6A, 7A
Or, it is derived from Group 8. As a specific example of the abrasive, α
-Alumina particles, silicon carbide particles, diamond particles,
Examples include magnesium oxide particles, zinc oxide particles, cerium oxide particles, zirconium oxide particles, colloidal silica particles, fumed silica particles, and the like. Use of one or more of these is preferred from the viewpoint of improving the polishing rate. Among them, α-alumina particles, cerium oxide particles, zirconium oxide particles, colloidal silica particles, fumed silica particles, and the like are more preferable, and α-alumina particles are particularly preferable.

The average particle size of the primary particles of the abrasive is preferably from 0.01 to 3 μm, more preferably from 0.02 to 0.8 μm, particularly preferably from 0.05 to 0.
5 μm. Further, when the primary particles are aggregated to form secondary particles, the average particle size of the secondary particles is similarly increased from the viewpoint of improving the polishing rate and reducing the surface roughness of the object to be polished. , Preferably 0.05 to 3 μm, more preferably 0.1 to 1.5 μm, particularly preferably 0.2 to 1.2 μm.
μm. The average particle size of the primary particles of the abrasive can be determined by observing with a scanning electron microscope (preferably 3000 to 30,000 times), analyzing the image, and measuring the particle size. The average particle size of the secondary particles can be measured as a volume average particle size by using a laser light diffraction method.

The specific gravity of the abrasive is preferably from 2 to 6, and more preferably from 2 to 5, from the viewpoints of dispersibility, supply to the polishing apparatus, and recovery and reuse.

The content of the abrasive is preferably in the roll-off reducing agent composition from the viewpoints of economical efficiency, reduction of surface roughness, and efficient polishing.
The content is 1 to 40% by weight, more preferably 2 to 30% by weight, and still more preferably 3 to 15% by weight.

The water in the roll-off reducing agent composition of the present invention is used as a medium, and its content is preferably from 50 to 9 from the viewpoint of efficiently polishing the object to be polished.
8.99% by weight, more preferably 60-98% by weight, even more preferably 70-95% by weight.

Further, the roll-off reducing composition of the present invention may contain other components as required.

Other components include organic acids and salts thereof other than the roll-off reducing agent, for example, organic acids and salts thereof such as polyvalent carboxylic acids, aminopolycarboxylic acids and amino acids, and inorganic acids and salts thereof. An oxidizing agent, a thickener, a dispersing agent, a rust inhibitor, a basic substance, a surfactant and the like can be mentioned. Specific examples of organic acids and salts thereof, inorganic acids and salts thereof, and oxidizing agents include JP-A-62-25187, page 2, upper right column, lines 3 to 11,
JP-A-63-251163, page 2, lower left column, lines 7 to 14;
No. 1-205973, page 3, upper left column, line 11 to upper right column, line 2,
No. 115383, page 2, lower right column, line 16 to page 3, upper left column, line 11,
No. 4-108887, page 2, lower left column, lines 1 to 9; JP-A-4-275387
No. 2, page 27, right column, line 27 to page 3, left column, line 12, and JP-A-4-363385, page 2, right column, lines 21 to 30.

These components may be used alone or
A mixture of more than one species may be used. Also, its content is
From the viewpoint of expressing the respective functions and the viewpoint of economy, preferably, the content of the roll-off reducing agent composition is 0.05 to 2%.
0% by weight, more preferably 0.05 to 10% by weight, still more preferably 0.05 to 5% by weight.

The concentration of each component in the roll-off reducing agent composition is a preferable concentration when polishing, but may be a concentration when the composition is manufactured. Usually, the composition is produced as a concentrated liquid, and this is often used after dilution.

The roll-off reducing composition of the present invention comprises a carboxylic acid having 2 to 20 carbon atoms, a monocarboxylic acid having 1 to 20 carbon atoms, a dicarboxylic acid having 2 to 3 carbon atoms, having the OH group or SH group. 1 selected from the group consisting of these salts
It can be produced by appropriately adding and mixing various or more additives by a known method, if necessary.

It is preferable that the pH of the roll-off reducing agent composition is appropriately determined according to the kind of the object to be polished, required quality and the like. For example, the pH of the roll-off reducing agent composition is preferably from 2 to 12, from the viewpoints of substrate cleaning properties, processing machine corrosion prevention properties, and operator safety. Further, when the object to be polished is a substrate for precision parts mainly intended for a metal such as a Ni-P plated aluminum alloy substrate, from the viewpoint of improving the polishing rate and improving the surface quality, 2 to 9 is more preferable. , 3 to 8 are particularly preferred. Moreover, polishing such as a semiconductor wafer or a semiconductor device, in particular a silicon substrate, a polysilicon film, when used for polishing, such as SiO ₂ film, from the viewpoint of improvement in improving the surface quality of the polishing rate, 7-12 preferably, 8 To 12 are more preferable, and 9 to 11 are particularly preferable. The pH is, if necessary, an inorganic acid such as nitric acid or sulfuric acid, a polyvalent carboxylic acid or an aminopolycarboxylic acid, an organic acid such as an amino acid, and a metal salt or an ammonium salt thereof, aqueous ammonia, sodium hydroxide, potassium hydroxide, It can be adjusted by appropriately mixing a basic substance such as an amine in a desired amount.

The material to be polished represented by the substrate to be polished, which is the object of the present invention, is, for example, a metal or semimetal such as silicon, aluminum, nickel, tungsten, copper, tantalum, titanium or the like, or a metal such as these. Examples include alloys, glass-like substances such as glass, glassy carbon, and amorphous carbon as main components, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium nitride, and resins such as polyimide resins. Of these, metals such as aluminum, nickel, tungsten, and copper and alloys containing these metals as main components are the objects to be polished, or semiconductor substrates such as semiconductor elements containing such metals are objects to be polished. It is preferred that In particular, it is preferable to use the roll-off reducing agent of the present invention when polishing a substrate made of a Ni-P-plated aluminum alloy, because the roll-off can be reduced.

The shape of the object to be polished is not particularly limited. For example, a shape having a flat portion such as a disk shape, a plate shape, a slab shape, a prism shape, or a shape having a curved surface portion such as a lens is used in the present invention. And a polishing target using the roll-off reducing agent composition. Among them, it is particularly excellent in polishing a disk-shaped object to be polished.

The roll-off reducing agent of the present invention is suitably used for polishing precision component substrates. For example, it is suitable for polishing a substrate of a magnetic recording medium such as a magnetic disk, an optical disk, and a magneto-optical disk, a photomask substrate, an optical lens, an optical mirror, an optical prism, and a semiconductor substrate. Polishing of a semiconductor substrate includes polishing performed in a polishing step of a silicon wafer (bare wafer), a step of forming a buried element isolation film, a step of flattening an interlayer insulating film, a step of forming a buried metal wiring, a step of forming a buried capacitor, and the like. The roll-off reducing agent composition of the present invention is particularly suitable for polishing a magnetic disk substrate.

In the method for reducing the roll-off of a substrate to be polished using the roll-off reducing agent of the present invention, the above-mentioned substrate to be polished may be treated with a polishing liquid containing the roll-off reducing agent of the present invention or the roll-off reducing agent of the present invention. By polishing using the agent composition itself as a polishing liquid, roll-off of the substrate to be polished can be significantly reduced.

For example, a polishing liquid containing the roll-off reducing agent of the present invention, or a polishing solution containing the roll-off reducing agent of the present invention is sandwiched between polishing substrates to which a nonwoven fabric-type organic polymer polishing cloth or the like is attached. By supplying the object to the polishing surface and moving the polishing board or the substrate while applying a constant pressure, a substrate with reduced roll-off can be manufactured.

In the present invention, the roll-off generated on the substrate to be polished is measured, for example, by using a stylus type or an optical shape measuring device, and the profile of the end surface is compared with the center of the disk from the profile. It can be evaluated by quantifying how much is removed.

As shown in FIG. 1, the method of digitization is to use three points on a measurement curve (meaning the shape of the end face portion of the substrate to be polished) such as points A, B and C which are at a certain distance from the center of the disk. A point is taken, a straight line connecting point A and point C is taken as a baseline, and the distance (D) between point B and the baseline is referred to. Good roll-off means that the value of D is closer to zero. The roll-off value is a value obtained by dividing D by の of the change in the thickness of the disk before and after polishing. The roll-off value is preferably 0.2 μm / μm or less, more preferably 0.15 μm / μm, and still more preferably 0.10 μm / μm.
μm.

The positions of point A, point B and point C vary depending on the size of the object to be measured. In general, point B is placed on a line connecting the end of the disk and the center from the end of the disk. 5
mm position, C point is 2.5 mm position, A point is 4.5 m
Preferably, the position is m. For example, in the case of a 3.5-inch disk, it is preferable that points A, B, and C are respectively 43 mm, 47 mm, and 45 mm from the center of the disk.

The use of the roll-off reducing agent of the present invention in the step of polishing a substrate for precision parts and the like has the advantage of not only significantly reducing the roll-off of the substrate but also improving the polishing rate. is there. In addition, oxalic acid, malic acid, tartaric acid, citric acid,
When gluconic acid and one or more of these salts are used,
Further, it is preferable because clogging of the polishing pad with abrasive grains and polishing swarf can be reduced, and deterioration of polishing characteristics such as polishing rate and surface quality due to long-term use of the polishing pad can be prevented.

In this case, among the above compounds, oxalic acid, tartaric acid, citric acid or a salt thereof is preferable, and citric acid or a salt thereof is particularly preferable. When two or more of the above compounds are used in combination, a particularly preferred combination is selected from oxalic acid, tartaric acid, citric acid and salts thereof.
A combination of at least one or oxalic acid, tartaric acid, citric acid and one or more selected from salts thereof and malonic acid;
A combination with at least one selected from glycolic acid, lactic acid, malic acid, gluconic acid and salts thereof is preferred,
Further, citric acid or a salt thereof and oxalic acid, glycolic acid,
1 selected from lactic acid, malic acid, tartaric acid and their salts
Combinations with more than one species are more preferred. A particularly preferred combination is citric acid or a salt thereof and glycolic acid or a salt thereof.

Although the polishing composition of the present invention is particularly effective in the polishing step, it can be similarly applied to other polishing steps such as a lapping step.

[0040]

Examples 1 to 10 and Comparative Examples 1 to 5 Abrasive (α-alumina having an average primary particle diameter of 0.23 μm and an average secondary particle diameter of 0.5 μm (purity: about 99.9%)) 7 Parts by weight, a predetermined amount shown in Table 1 of the roll-off reducing agent used in the examples and the compound used in the comparative examples, and the remainder of the ion-exchanged water were mixed and stirred. 4 was adjusted to pH 4 with aqueous ammonia, and Comparative Examples 1 and 5 were adjusted to p with nitric acid.
H was adjusted to 4 to obtain 100 parts by weight of the compositions of Examples 1 to 10 and Comparative Examples 1 to 5.

Using the obtained composition, a tally step (probe tip size: 25 μm) manufactured by Rank Taylor Hobson KK
m × 25μm, high pass filter: 80μm, measurement length:
0.64mm), the center line average roughness Ra is 0.2 μm
The surface of a substrate made of a Ni-P plated aluminum alloy having a thickness of 0.8 mm and a diameter of 3.5 inches is polished by a double-sided processing machine under the following double-sided processing machine setting conditions, and Ni used as a substrate for a magnetic recording medium is used. A polished aluminum alloy substrate plated with -P was obtained.

The setting conditions of the double-side processing machine are shown below. <Setting conditions of double-sided processing machine> Double-sided processing machine: Speed Farm Co., Ltd., 9B type double-sided processing machine Processing pressure: 9.8 kPa Polishing pad: Polytex DG-H (Rodel Nitta) Surface plate rotation speed: 50r / min Polishing composition supply flow rate: 100 ml / min Polishing time: 5 min Number of substrates loaded: 10

After polishing, the roll-off value generated on the substrate to be polished was determined by the following measurement method, and the relative value was determined based on Comparative Example 2. In addition, the thickness of the aluminum alloy substrate of the embodiment was measured using a film thickness meter (manufactured by Mitutoyo Corporation, laser film thickness meter Mo).
del LGH-110 / LHC-11N) to determine the rate of decrease in thickness from the change in thickness of the aluminum alloy substrate before and after polishing, and to determine the relative value (relative polishing rate) based on Comparative Example 1. Was. Table 1 shows the results.

<Measurement method of roll-off> Measuring device: Mitutoyo Form Tracer SV-C624 Contact tip radius: 2 μm (code No. 178-381) Contact pressure: 0.7 mN or less Speed: 0.2 mm / s Analysis software: SV-600 fine contour analysis system version1.0
1 Filter: LPF (Gaussian) 0.800mm

Using the above apparatus, the shape of the edge of the disk at a distance from the center of the disk of 42.5 mm to 47.5 mm was measured, and the positions of points A, B and C were respectively 43 mm, 47 mm and 45 mm from the center of the disk. Then, D was obtained by the above-described measurement method using analysis software. The value obtained by dividing the obtained D by 1/2 of the amount of change in the thickness of the disk before and after polishing was defined as a roll-off value.

[0046]

[Table 1]

From the results in Table 1, it can be seen that the roll-off reducing compositions obtained in Examples 1 to 10 all have significantly reduced roll-off as compared with the roll-off reducing compositions obtained in Comparative Examples 1 to 5. It can be seen that it has been reduced. In addition, it can be seen that the polishing rates of Examples 1 to 10 in which the roll-off reducing agent was contained were improved as compared with Comparative Example 1 in which the roll-off reducing agent was not added.

Examples 4, 10 and Comparative Example 3
Using the polishing composition prepared in the above, the polishing evaluation described above was repeated 20 times, and 20 times the first relative polishing rate.
When the ratio of the relative polishing speed at the time of the polishing was measured as the clogging prevention performance, it was 0.97 in the polishing composition of Example 4, 0.95 in Example 10, and 0.62 in Comparative Example 3.
Met. In addition, from the evaluation results of the pad clogging prevention ability of Examples 4 and 10 and Comparative Example 3, Examples 4 and 10 show Comparative Example 3.
On the other hand, it can be seen that there is little deterioration in the polishing rate and there is excellent pad clogging prevention performance.

[0049]

By using the roll-off reducing agent of the present invention for polishing a substrate for precision parts, the roll-off of the substrate can be significantly reduced and the polishing rate can be improved. Is done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a measurement curve and roll-off.

Continuation of front page (72) Inventor Yoshiaki Oshima 1334 Minato, Wakayama-shi Kao Corporation Research Laboratory F-term (reference) 3C047 GG00 3C058 AA07 AC04 DA17 5D112 AA02 AA24 BA06 GA14 JJ01

Claims (4)

[Claims] An OH or SH group having 2 to 2 carbon atoms.
A roll-off reducing agent selected from the group consisting of a carboxylic acid having 0, a monocarboxylic acid having 1 to 20 carbon atoms, a dicarboxylic acid having 2 to 3 carbon atoms, and salts thereof. 2. An OH or SH group having 2 to 2 carbon atoms.
0 carboxylic acid, monocarboxylic acid having 1 to 20 carbon atoms, dicarboxylic acid having 2 to 3 carbon atoms and one or more roll-off reducing agents selected from the group consisting of salts thereof, an abrasive and water. Roll-off reducing agent composition. 3. An OH or SH group having 2 to 2 carbon atoms.
0 carboxylic acid, monocarboxylic acid having 1 to 20 carbon atoms, dicarboxylic acid having 2 to 3 carbon atoms, and at least one roll-off reducing agent selected from the group consisting of salts thereof. How to reduce roll-off. 4. An OH or SH group having 2 to 2 carbon atoms.
A method for producing a substrate to be polished using one or more roll-off reducing agents selected from the group consisting of a carboxylic acid of 0, a monocarboxylic acid of 1 to 20 carbon atoms, a dicarboxylic acid of 2 to 3 carbon atoms and salts thereof. .