JP2000129243A - Polishing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition being useful to polish the surface of a semiconductor, preferentially polishing a metallic layer and having excellent long- term storage stability by incorporating α-alumina, an antisettling agent for abrasive grains, an oxidizing agent, an insulation film abrasion inhibitor, a metal layer abrasion accelerator, an aqueous medium, and a pH buffer. SOLUTION: It is desirable that the total amount of the α-alumina used and the antisettling agent used is 2-15 wt.% that the primary particle of the α-alumina used is 10-150 nm in terms of a mean particle diameter, and the α-alumina used accounts for 10-70% of the total weight of the α-alumina used and the antisettling agent used. The antisettling agent is desirably the one selected from gibbsite, etc. The oxide is selected from aluminum nitrate, etc., and is used in an amount of 0.5-5 wt.%. Desirably, the abrasion inhibitor is selected from potassium hydrogenphthalate, etc., and is used in an amount of 0.1-3 wt.%, the abrasion accelerator is selected from ascorbic acid, etc., and is used in an amount of 0.1-5 wt.%, and the pH buffer is selected from citric acid, etc., and is used in an amount of 0.1-5 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing composition used for polishing a semiconductor surface, and more particularly to a polishing slurry which is most suitable for flattening the surface of a multilayer wiring silicon wafer.

More generally, the present invention has discovered an anti-settling agent for dispersing abrasive particles which are likely to settle for a long time, and an accelerator for selectively polishing only the metal layer and an interlayer insulating film. A suitable combination that finds a polishing inhibitor that prevents polishing at the same speed as metal layer polishing, and that the accelerator and the inhibitor do not react with each other and reduce the expected effect by half. And a polishing composition combining them.

[0003]

2. Description of the Related Art Recent semiconductor integrated circuits have become finer and denser each year. In addition, it is moving in the direction of multilayering. For example, the wiring line diameter of 64 megabytes is 0.25 μm and the density (Bits / cm ² ) is 96M, but when it becomes 256 megabytes, the wiring line diameter is further reduced to 0.18 μm, and the density (Bit
s / cm ² ) is expected to be as high as 70M. The number of layers is also expected to increase from three to five.

[0004] As described above, the wiring provided in the semiconductor integrated circuit is miniaturized and the density is increased, and the product yield of the substrates stacked in multiple stages depends on whether or not the polished surface can be finished flat. More specifically, as shown in the example of the enlarged wiring diagram shown in FIGS. 1 and 2, a metal layer 2 and an interlayer insulating film 3 are laminated and polished on a substrate 1, and the next layer is laminated and polished. In a repetitive pattern to be performed, a selective polishing mechanism that does not polish any more when polishing progresses and reaches a certain multi-layer insulating film is required. If there is no selectivity and both materials are polished at the same rate, the progress of polishing does not stop and the remaining layers are also removed. As described above, when a selective polishing slurry is developed in which the metal layer 2 is polished but the interlayer insulating film 3 is not polished, the purpose of flattening can be achieved for the first time.

More specifically, when the selectivity value is shown in the case of tungsten metal as a metal, the ratio of the polishing rate between tungsten and the interlayer insulating film is at least 5: 1 or more, preferably 10: 1 or more. Is required.

The present inventors have found that, in polishing a metal layer and an interlayer insulating film, α-alumina, ammonium hydrogen phthalate, and KlO as an oxidizing agent are used as a slurry having a high polishing rate for the metal layer and a high selectivity. _3. A polishing composition containing an aqueous solvent and a submicron abrasive was proposed (Japanese Patent Application No. 9-515279).

[0007]

However, this composition has a very high polishing rate for the metal layer and a high selectivity, but when incorporated in an actual process, the slurry has a long dispersibility, erosion, scratch, etc. Has not been completely solved and there is room for improvement. In other words, α-alumina, which tends to settle, precipitates at the bottom of the container and causes aggregation, and the aggregates cannot be sufficiently re-dispersed, so that the polished surface is scratched or eroded. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and a slurry used for chemical and mechanical polishing can obtain a large selectivity and a perfect surface free from scratches which have been conventionally required. It is an object of the present invention to provide a polishing composition which can be used.

[0009]

The polishing composition of the present invention comprises α-alumina, an aqueous solvent, an abrasive sedimentation inhibitor, an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator and a pH buffering agent. And the above-mentioned object is achieved.

[0010] In one embodiment, the total weight of the α-alumina and the abrasive sedimentation inhibitor is 2 to 15% by weight.

[0011] In one embodiment, the α-alumina has a primary particle size of T.P. E. FIG. The average particle diameter measured by the M method is 10 to 150 nm.

In one embodiment, the α-alumina accounts for 10 to 70% by weight based on the total weight of the α-alumina and the abrasive sedimentation inhibitor.

In one embodiment, the abrasive anti-settling agent is selected from the group consisting of gypsite, bayerite, heidilite, boehmite, gamma alumina, delta alumina, fumed silica, and colloidal silica.

In one embodiment, the oxidizing agent is aluminum nitrate, iron nitrate, ammonium nitrate, zirconium nitrate,
KL0 _3, selected from the group consisting of ammonia water and H ₂ 0 _2, the amount added is contained 0.5-5 wt%.

In one embodiment, the insulating film polishing inhibitor comprises potassium hydrogen phthalate, ammonium hydrogen phthalate, polyvinylpyrrolidone, ammonium hydrogen succinate,
It is selected from the group consisting of propylene glycol, ethylene glycol and polyvinyl alcohol, and is contained in an amount of 0.1 to 3% by weight.

In one embodiment, the metal layer polishing accelerator is ascorbic acid, oxalic acid, salicylic acid and salts thereof, and is contained in an amount of 0.1 to 5% by weight.

In one embodiment, the pH buffer comprises:
Selected from the group consisting of citric acid and phosphates;
1-5% by weight.

In one embodiment, the pH of the polishing composition (whole slurry) is controlled with a chemical selected from the group consisting of aqueous ammonia, piperazine, NaOH and KOH, and the pH after adjustment is adjusted to 3.0 to 3.0. 4.8
It is characterized by being.

In one embodiment, the composition is a polishing composition which is separated and stored in a liquid A and a liquid B and mixed immediately before polishing, wherein the liquid A comprises α-alumina, The solution B contains an inhibitor, an aqueous solvent, and is adjusted to pH 3.0 to 4.8. The solution B contains an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator, an aqueous solvent, and a pH buffer. Then p
H is adjusted to 3.0 to 4.8.

(Specific description of the invention) α- used as a main abrasive in the polishing composition (polishing slurry) of the present invention.
Alumina is a high-temperature sintered body with crystal growth suppressed, even if wet crushed, fumed alumina is further processed at high temperature,
Even if it is pregelatinized and then crushed, it may be any of the pre-gelatinized one by evaporating the alumina sintered body instantly by using an ultra-high temperature heat source such as plasma or laser, and then vapor-phase precipitating. It is not limited.

Examples of the abrasive sedimentation preventive include fibrous cellulose and organic polymer dispersants. For α-alumina, amorphous or similar alumina having the same chemical composition is more effective. Is the target. The reason is that the dispersibility with α-alumina is much better than cellulose or the like by having the same chemical composition.

The anti-settling agent suitable for α-alumina is desirably high-purity alumina in which amorphous boehmite and hydride and gamma-crystalline alumina which is a loose crystal are mixed. Colloidal silica and fumed silica can also be used as good sedimentation preventive agents. However, when these are used, they have different isoelectric points, so that the sedimentation preventive agent is subjected to an activation treatment, which is disclosed in Japanese Patent Application No. 7-508250. It is good to use after equipotential point control.

The total weight of α-alumina and the anti-settling agent is preferably 2 to 15% by weight of the polishing slurry, more preferably 3 to 8% by weight. Polishing using a high-concentration slurry exceeding 15% by weight sometimes causes clogging of the polishing pad, causing not only poor polishing, but also uneconomical. On the other hand, if the concentration is lower than 2% by weight, the polishing time is too long and the workability is reduced, which is not practical.

Further, the ratio of α-alumina and the anti-settling agent is preferably from 10 to 70% by weight, more preferably from 20 to 40% by weight, based on the total of these. If the content exceeds 70% by weight, the amount of the anti-settling agent is too small to maintain a uniform dispersion state, and expensive α-alumina is used in large quantities, which is uneconomical. On the other hand, if it is less than 10% by weight, it is easy to uniformly disperse and stabilize, but the polishing speed decreases and the workability deteriorates.

The particle size of α-alumina used here is as follows:
T. E. FIG. 10 to 150 n in primary particle average diameter measured in M
m, preferably 30 to 80 nm. When the average primary particle diameter is larger than 150 nm, it is liable to cause a scratch, and a particle smaller than 30 nm cannot be easily produced.

The oxidizing agent is preferably selected from among aluminum nitrate, iron nitrate, ammonium nitrate, zirconium nitrate, K10 ₃ , aqueous ammonia and H ₂ O ₂ . More preferably from KL0 _3. Iron nitrate depends on the performance of the wafer cleaning equipment. If the cleaning power of the equipment is inferior, it is not preferable to use it as an oxidizing agent since Fe remains attached to the wafer.

The amount of the oxidizing agent is preferably 0.5 to 5% by weight, more preferably 2 to 4% by weight. 5% by weight
If the amount is too large, a recess is caused. If the amount is less than 0.5 weight, the speed of oxidizing the metal layer is reduced, and the polishing rate is not increased.

Insulating film polishing inhibitors include ammonium hydrogen phthalate, potassium hydrogen phthalate, polyvinylpyrrolidone, ammonium hydrogen succinate, propylene glycol,
It is preferably selected from the group consisting of ethylene glycol and polyvinyl alcohol, more preferably ammonium hydrogen phthalate or polyvinyl pyrrolidone.

Although potassium hydrogen phthalate has a sufficient inhibitory effect, it is difficult to dissolve in an aqueous solvent. On the other hand, ammonium hydrogen succinate may not have a sufficient inhibitory effect depending on polishing conditions.

The addition amount of the insulating film polishing inhibitor is preferably from 0.1 to 3% by weight, more preferably from 0.5 to 1.0% by weight. In addition, it is not preferable because it becomes difficult to cause slurry foaming. It is preferable that the metal layer polishing accelerator, which does not sufficiently exert an inhibitory effect with an addition amount of less than 0.1% by weight, be selected from the group consisting of ascorbic acid, oxalic acid, salicylic acid and salts thereof. Preferably, the metal layer polishing accelerator is included in the slurry in an amount of 0.1 to 5% by weight,
Salicylic acid and salts. The concentration is more preferably 1 to 3%. Salicylic acid not only has the effect of promoting polishing of the metal layer but also has the effect of suppressing polishing of the insulating film.

The pH buffer is preferably selected from the group consisting of citric acid and phosphates, and 0.1 to 5% by weight is preferably added. As phosphates, for example,
There is potassium dihydrogen phosphate. More preferably, it is citric acid, and its concentration is 1 to 3%. In particular, citric acid is advantageous because it does not cause complicated interactions with other chemicals added to the slurry.

The pH of the slurry is preferably controlled with aqueous ammonia, piperazine, NaOH or KOH, and more preferably with aqueous ammonia or KOH.
OH. Even if potassium ions remain on the silicon wafer, KOH does not easily diffuse into the inside of the silicon wafer and can be easily washed. On the other hand, since NaOH has a small atomic radius of sodium ions, it diffuses and penetrates into the inside of the silicon wafer, cannot be completely washed, remains on the wafer surface, changes the electrical characteristics of the silicon wafer, and may cause a semiconductor product defect.

[0033] The pH of the slurry is preferably in the range of 3.0 to 4.8, and more preferably 3.0 to 4.0. p
As H rises to 4.8 or more, α-alumina as an abrasive contained in the composition tends to aggregate. One indicator of aggregation is the zeta potential, whereas alumina has a pH of 5.
It has an equipotential point (where the zeta potential becomes ± 0 mv) in the range of 5 to 7.5, and in this vicinity, repulsion due to particle charging cannot be expected, and aggregation is likely. On the other hand, if the pH is 3.0
When it is lower, the zeta potential is large and the particle dispersion is stable, but the acid polishing of the precision polishing machine may be caused, and the effect of suppressing the polishing of the insulating layer is reduced.

As the aqueous solvent used in the present invention, water, ethanol, methanol and the like, and a mixed solvent thereof can be used, and preferably, deionized pure water is used.

As described above, α-alumina, an aqueous solvent, an abrasive sedimentation inhibitor, an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator, and a buffer are mixed to form a predetermined range (preferably 3.0). To 4.8) (slurry (polishing composition)). The polishing composition of the present invention is particularly excellent for polishing aluminum, tungsten and barrier metal layers.

In the present invention, in particular, the polishing composition is separated and stored in a plurality of liquids (for example, liquid A and liquid B), and these are uniformly mixed at the time of use, so that the polishing composition can be stored for a long time (about 1).
Years) dispersion stability can be improved.

For example, an abrasive and a grain sedimentation inhibitor are added to the solution A, and the pH is adjusted with a known acid and alkali (for example, KOH) to form a slurry. Here, as the known acid, oxalic acid, sulfuric acid, nitric acid, phosphoric acid, and the like can be used. As the alkali, the above-mentioned ammonia water, piperazine,
NaOH and KOH can be used. The solution B is a chemical solution obtained by dissolving an oxidizing agent, a polishing inhibitor for a green film, a metal layer polishing accelerator, and a buffer in an aqueous solvent.

The polishing composition of the present invention contains a pH buffer so as to prevent a large pH fluctuation of the slurry due to dissolution of a part of the metal layer shaved during the actual polishing operation. it can.

That is, there is an appropriate pH at which the function of the insulating film polishing inhibitor contained in the composition is sufficiently exerted,
It is described in Japanese Patent Application No. 7-501033 that the inhibitory effect is lost when the pH is out of the proper range. Therefore pH
It is very important to keep constant. However, when the polishing operation was actually performed, it was found that the pH of the slurry fluctuated because a part of the metal layer shaved during the polishing was dissolved. This countermeasure is disclosed in Japanese Patent Application Nos. 7-501033 and 9
In the case of -515279, the buffer was not contained and was insufficient.

Further, in the present invention, the polishing rate of the metal layer can be improved by using the metal layer polishing accelerator.

That is, when attention is paid to polishing of the metal layer, the oxidizing agent acts on the metal layer to form an oxide MOx on the surface of the metal layer. It is quickly removed and the active surface of the metal layer is always exposed, so that the next moment the oxidizer is attacked. The mechanism by which the polishing rate is improved by repeating this phenomenon has become clear. The accelerator plays a role of quickly removing the oxide MOx.
In Japanese Patent Application No. 501033 and Japanese Patent Application No. 9-515279, the selection of the accelerator was not sufficient.

In addition, the greatest unknown unknown in a slurry containing chemicals satisfying each function is that an anti-settling agent, an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator, and a pH buffering agent are unexpectedly present. Although a complex reaction was caused to reduce the expected effect by half, in the embodiment of the present invention, α-alumina, aqueous solvent, abrasive sedimentation inhibitor, oxidizing agent, insulating film polishing inhibitor, metal layer A polishing composition comprising a polishing accelerator and a buffer for preventing pH fluctuation,
Storing the slurry in two parts, a liquid and a liquid B, can maintain the long-term stability of the slurry for one year.

In this case, the liquids A and B of the composition are uniformly mixed at the time of use, and are used when polishing a metal wiring substrate, particularly a metal layer, and are flat and free from scratches such as scratches, erosion and dishing. To obtain a polishing composition.

Here, the erosion generation mechanism will be described in detail with an example of tungsten metal polishing.

When the tungsten polishing is completed at a predetermined film thickness,
If polishing is completed when the interlayer insulating film is exposed, the portion of the insulating film is not eroded any more. (No erosion.) However, in many cases, the end point is not clear and the force of overpolishing continues to be applied. In this state, the remaining portion of the interlayer insulating film material receives erosion because it receives a higher polishing pressure than the other portions. When an effective interlayer insulating film polishing inhibitor is used for the slurry and the insulating film is sufficiently protected, erosion is less likely to occur even in an excessively polished state.

[0046]

EXAMPLES (Preparation of Polishing Composition) (Preparation of Solution A) The following weight percent of α-alumina and an abrasive sedimentation inhibitor were strongly crushed with a medium stirring mill (beads mill) to form a slurry. The stock solution was used.

Α-alumina abrasive grains have an average particle diameter of 200 n
m, 150 nm, and 100 nm are prepared. The abrasive concentration is 7.5% by weight and 21% for the 200 nm size.
Three types of weight% and 30 weight% were prepared. Others are 30
A weight% slurry was obtained.

A-α-alumina (200 nm) 30 kg Aqueous solvent adjusted to pH 3.2 with nitric acid 70 kg A-α-alumina (150 nm) 30 kg Aqueous solvent adjusted to pH 3.2 with nitric acid 70 kg A-α-alumina (100 nm) 30 kg) Aqueous solvent adjusted to pH 3.2 with nitric acid 70 kg A-α-alumina (200 nm) 7.5 kg Abrasive sedimentation inhibitor (mixture of boehmite and gamma alumina) 22.5 kg Aqueous solvent adjusted to pH 3.2 with nitric acid 70 kg A-α-alumina (200 nm) 21 kg Abrasive sedimentation inhibitor (mixture of boehmite and gamma alumina) 9 kg Aqueous solvent adjusted to pH 3.2 with nitric acid 70 kg

(Preparation of Solution B) A solution having the following composition was prepared as a drug B stock solution.

B-1 Stock solution-oxidizing agent (KlO ₃ ) 4 kg Insulating film polishing inhibitor (polyvinylpyrrolidone) 1 kg Metal layer polishing accelerator (salicylic acid) 3 kg pH buffer (citric acid) 2 kg Adjusted to pH 3.2 with nitric acid Aqueous solvent 90 kg B-2 stock solution Oxidizing agent (KlO ₃ ) 4 kg Insulating film polishing inhibitor (ammonium hydrogen phthalate) 1 kg Metal layer polishing accelerator (salicylic acid) 3 kg pH buffer (citric acid) 2 kg Nitric acid to pH 3.2 Prepared aqueous solvent 90 kg B-3 stock solution Oxidizing agent (KlO ₃ ) 4 kg Insulating film polishing inhibitor (ammonium hydrogen phthalate) 1 kg Aqueous solvent 95 kg B-3 stock solution adjusted to pH 3.2 with nitric acid is a polishing accelerator, buffer No agent was added.

The solid content in the slurry of α-alumina or the slurry of α-alumina and the abrasive sedimentation preventing agent was determined between the A solution and the B solution.
When the liquids were mixed, they were adjusted to be approximately 5% by weight. Specifically, A- ~ A- stock solution 1 part, B-1 stock solution ~
The B-3 stock solution (5 parts) was uniformly mixed and subjected to polishing of a 6-inch silicon wafer on which wiring was drawn.

(Polishing Machine) As a precision polishing machine, Westech 372M type machine (platen diameter 24 inches) was used. The surface plate of the polishing machine has a polyurethane polishing pad (Rode)
1C-1000 / suba IV) was attached and used.

(Polishing condition) The polishing condition is a processing pressure of 7 ps.
i, platen rotation 50 rpm, polishing slurry supply amount 125 c
c / min, wafer rotation speed 90rpm, back pressure 0ps
i.

(Measurement) Removal distance (Å / min): Measurement was performed by a metal mapping system of Tencor Corporation.

Erosion data: Digital I
The measurement was performed by the AFM method manufactured by Nstruments.

Particle Remaining State: Photographs were judged with a Normalsky differential interference microscope.

(Measurement Results) The results of the polishing rate for tungsten, the polishing rate for titanium, and the polishing rate for the insulating film are summarized in Table 1.

[0058]

[Table 1]

(Consideration) When the average particle diameter of α-alumina was gradually reduced, there was a possibility that the polishing rate was decreased instead of the scratch (scratch).
There was no significant difference between 150 nm and 100 nm.

The green film polishing inhibitor is changed from ammonium hydrogen phthalate to polyvinyl pyrrolidone (PVP).
When I tried it, the insulating film was more strongly protected, PV
P was found to be more selective than ammonium hydrogen phthalate. It was proved that the erosion at this time was not more than the target of 500 °. The dishing also satisfied the target of 110 ° or less.

It is further surprising that the number of particles remaining on the surface of the insulating film after polishing and washing has been drastically reduced. FIGS. 3 and 4 show the results of photographing by the normal ski method. The number of white spots indicates the remaining particles, and the combination of A- / B-1 indicates that the teaching is extremely small.

[0062]

According to the present invention, the aluminum metal layer, the tungsten metal layer, and the barrier metal layer of the highly integrated circuit drawn on the surface of the silicon wafer have a good dispersion state even after long-term storage for about one year. In the polishing of an interlayer insulating film, it is possible to provide a polishing composition which does not leave processing scratches such as scratches, erosion, dishing, etc., and can selectively polish a metal layer preferentially and hardly polishes an insulating film. it can.

In particular, when the polishing composition is separated into two or more liquids, it is mixed and used immediately before use, so that there is little sediment even after long-term storage and excellent dispersibility.

Therefore, there is provided an innovative polishing slurry which has not been generated in the past and has no scratches caused by the coarse particles, and no erosion and dishing due to the action of the antistatic agent. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross-sectional structure of a semiconductor integrated circuit in which a metal layer and an interlayer insulating layer are stacked on a silicon wafer substrate, and shows a state where the surface is not polished.

FIG. 2 is a schematic diagram showing a cross-sectional structure of a semiconductor integrated circuit in which a metal layer and an interlayer insulating layer are stacked on a silicon wafer substrate, and shows a state where the surface is polished flat.

FIG. 3 is an electron micrograph of a surface of an insulating film after polishing and washing, which is obtained by a normal ski method, using a polishing composition (combination of A- / B-1) used in Examples.

FIG. 4 is an electron micrograph of a surface of an insulating film after polishing and washing, which is obtained by a normal ski method, using a polishing composition (A- / B-3 combination) used in a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon wafer substrate 2 Metal layer 3 Interlayer insulating film

Claims (11)

[Claims] 1. A polishing composition comprising α-alumina, an aqueous solvent, an abrasive sedimentation inhibitor, an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator, and a pH buffering agent. . 2. The polishing composition according to claim 1, wherein the total weight of the α-alumina and the abrasive sedimentation inhibitor is 2 to 15% by weight. 3. The α-alumina having a primary particle size of T.P.
E. FIG. 10 to 150 nm in average particle diameter measured by M method
The polishing composition according to claim 2, which is: 4. The polishing composition according to claim 2, wherein the α-alumina contained in the total weight of the α-alumina and the abrasive sedimentation inhibitor is 10 to 70% by weight. 5. The polishing agent according to claim 4, wherein the abrasive sedimentation inhibitor is selected from the group consisting of gypsite, bayerite, heiligite, boehmite, gamma alumina, delta alumina, fumed silica and colloidal silica. Composition. 6. The oxidizing agent is selected from the group consisting of aluminum nitrate, iron nitrate, ammonium nitrate, zirconium nitrate, K10 ₃ , aqueous ammonia and H ₂ O ₂ ,
The polishing composition according to claim 1, which is contained by weight. 7. The insulating film polishing inhibitor is selected from the group consisting of potassium hydrogen phthalate, ammonium hydrogen phthalate, polyvinyl pyrrolidone, ammonium hydrogen succinate, propylene glycol, ethylene glycol and polyvinyl alcohol, The polishing composition according to claim 1, which is contained in an amount of 3% by weight. 8. The metal layer polishing accelerator is ascorbic acid, oxalic acid, salicylic acid and salts thereof,
The polishing composition according to claim 1, which is contained in an amount of 5% by weight. 9. The polishing composition according to claim 1, wherein the pH buffer is selected from the group consisting of citric acid and phosphates, and is contained in an amount of 0.1 to 5% by weight. 10. The pH control of the polishing composition,
It is made of a chemical selected from the group consisting of ammonia water, piperazine, NaOH and KOH, and has a pH adjusted to 3.
The polishing composition according to claim 1, wherein the polishing composition has a ratio of 0 to 4.8. 11. The polishing composition according to claim 1, wherein the composition is separated and stored in a liquid A and a liquid B, and mixed immediately before use. The solution B contains an anti-settling agent and an aqueous solvent, and is adjusted to pH 3.0 to 4.8. The B solution is an oxidizing agent, an insulating film polishing inhibitor, a metal layer polishing accelerator, an aqueous solvent and a pH buffering agent. And has a pH of 3.0 to 3.0.
A polishing composition adjusted to 4.8.