JP3353510B2 - Chemical mechanical polishing method, chemical mechanical polishing apparatus, and semiconductor device manufacturing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing semiconductor devices and the like.
Relates chemical mechanical polishing method and a chemical mechanical polishing apparatus in, more particularly to flat processing step of the example manufacturing process interlayer insulating film and the electrode wiring on the substrate to be processed that occurs in, suitable for global planarization The present invention relates to a chemical mechanical polishing method, a chemical mechanical polishing apparatus, and a method for manufacturing a semiconductor device .

[0002]

2. Description of the Related Art The degree of integration of semiconductor devices such as LSIs has increased.
As the design rules are refined from sub-half micron to quarter micron, the pattern width of the internal wiring is also being reduced. On the other hand, in order to keep the wiring resistance at a low level and prevent delay in signal propagation and various migrations, it is necessary to secure a cross-sectional area of the wiring. That is, since the height of the wiring cannot be reduced so much, the aspect ratio of the wiring tends to increase.

In order to form a multilayer wiring structure having such fine wiring as a lower layer, a flattening interlayer insulating film is formed so as to fill a step or a recess formed by the lower wiring to secure a flat surface. It is necessary to repeat the process of forming the upper layer wiring thereon. This is important not only to prevent disconnection of the upper wiring, but also from the viewpoint of compensating for a decrease in the depth of focus due to a shorter wavelength of exposure light in lithography for resist patterning and a higher NA of the lens. As an example, KrF having a wavelength of 248 nm
In order to pattern a 0.3 μm rule line and space with good controllability by excimer laser stepper exposure, the surface step of the exposed surface is required to be 0.3 to 0.4 μm or less.

Conventionally, various methods for forming a planarized interlayer insulating film have been developed. For example, monthly Semiconductor World Magazine (published by Press Journal), November 1989, 7th edition.
A review of these formation methods is provided on pages 4-95. These forming methods either improve the self-flow characteristics by optimizing the film forming conditions, or improve the reflow shape by heat treatment after film forming. In any of the methods, there is room for improvement with respect to the flat shape of the interlayer insulating film in a stepped recess having a large wiring interval and prevention of voids in the interlayer insulating film in a portion having a small wiring interval.

On the other hand, in recent years, a global flattening method by chemical mechanical polishing (CMP) applying a mirror polishing method of a silicon wafer has been proposed. The chemical mechanical Migaku Ken method is a promising method for reliably planarize various steps of the target substrate once formed.

FIG. 4 is a schematic sectional view showing a conventional chemical mechanical polishing apparatus. In the figure, the rotating carrier 12
The substrate 11 to be processed, which is attached with the polished surface facing downward, is set so as to face a platen 13 which is also a rotating polishing plate. A slurry 17 is supplied from a slurry supply system 15 to a polishing cloth called a pad 14 on a platen via a nozzle 16, and the substrate 11 to be processed is pressed against the pad 14 at a predetermined pressure to perform polishing. At this time, the adjustment of the rotation speed and rotation axis of the carrier 12 and the platen 13 is optimized, and the polishing particles and pH suitable for the substrate to be processed are adjusted.
One of the points is the selection of slurries having the same. As an example, in the case of polishing a silicon oxide-based interlayer insulating film, a so-called CMP (CMP) in which a chemical reaction and mechanical polishing are used in combination using a KOH aqueous solution or the like in which fine silica particles are suspended is used.
chemical-Mechanical Polish
ing).

[0007]

However, the flattening method by the chemical mechanical polishing method has problems to be solved for practical use. One of the reasons is that the polishing rate for flattening is low, and polishing of one substrate to be processed usually requires 10 minutes or more. In the planarization of an interlayer insulating film, a silicon oxide-based insulating film or the like that is thickly deposited by absorbing a step of an underlying wiring layer or the like is polished, so that an improvement in throughput by increasing the polishing rate is an important issue. .

Another problem is that the polishing rate depends on the pattern. That is, a difference may occur between the polishing rate of the step protrusion having a small area and the polishing rate of the step protrusion having a large area. In the case of flattening the interlayer insulating film, the polishing rate of the stepped portion having a large area is reduced, and the controllability of flattening in this portion is deteriorated.

In order to solve these problems, a part of the step protrusion in the thickness direction of the interlayer insulating film is removed in advance by isotropic etching using a resist pattern as a mask.
Thereafter, a method of performing chemical mechanical polishing is disclosed in U.S. Pat.
No. 4,459. This method is illustrated in FIG.
This will be described with reference to FIG.

A plurality of wiring layers 2 having different line widths are patterned on a first interlayer insulating film 1 on a semiconductor substrate (not shown), and a second interlayer insulating film 3 is formed thick. The second interlayer insulating film 3 has a mixture of step protrusions having a large area and step protrusions having a small area. If the polishing is carried out in this state, the polishing rate of the step protrusion having a large area is particularly reduced, which is satisfactory. Global flattening cannot be achieved. Therefore, a resist pattern 4 is formed in the step recess as shown in FIG. 3A, and a part of the step pattern in the thickness direction of the interlayer insulating film is removed as shown in FIG. When the resist pattern 4 is removed, the second interlayer insulating film 3 is removed as shown in FIG.
Only leave microprojections. Since the microprojections have a substantially uniform volume, the polishing time can be reduced by polishing from the state shown in FIG. 3 (c), and as shown in FIG. Excellent flattening can be achieved.

According to this prior art, flattening independent of the underlying wiring pattern can be achieved, but it is necessary to add a process of forming a resist pattern, etching and removing the resist pattern. A new problem that the throughput is reduced occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemical mechanical polishing method and a chemical mechanical polishing apparatus which have a higher polishing rate than conventional ones and are excellent in a flattened shape independent of a pattern.

[0013]

SUMMARY OF THE INVENTION The chemical mechanical polishing method of the present invention is proposed to solve the above-mentioned problem, and comprises a step of flattening a surface of a substrate having a step. In the method, chemical mechanical polishing is performed while applying ultrasonic waves to the substrate to be processed. Further, chemical mechanical during polishing Luke continuously or stepwise changing the amplitude of the ultrasonic wave, in the chemical mechanical polishing step Ru continuously or stepwise changing <br/> ultrasonic frequency Or applying ultrasonic waves of multiple frequencies simultaneously ,
Or even characterized by intermittently applying ultrasonic waves
It is.

Further, the chemical mechanical polishing apparatus of the present invention is a chemical mechanical polishing apparatus for flattening a substrate having a step, which comprises means for applying ultrasonic vibration to the substrate to be processed and control means therefor. It is characterized by having. The ultrasonic vibration applying means only needs to excite either the platen or the carrier of the chemical mechanical polishing apparatus. As the ultrasonic vibration applying means, a known piezoelectric or electromagnetic type electric / acoustic transducer can be used. The control means of the ultrasonic vibration applying means controls the input to the electric / acoustic transducer, and a computer or the like in which a control program is input in advance can be used. Further, in the method of manufacturing a semiconductor device according to the present invention, in the manufacturing method including a step of flattening a surface of the substrate to be processed having a step by chemical mechanical polishing, the chemical mechanical polishing is performed while applying ultrasonic waves to the substrate to be processed. one of the time, during the chemical mechanical polishing step, continuous or stepwise variation of the ultrasonic wave amplitude or frequency applied ultrasonic simultaneous application of a plurality of frequencies, intermittent application of ultrasound
It is characterized in that to perform.

[0015]

The point of the present invention is that ultrasonic waves are applied to the substrate to be processed during the chemical mechanical polishing process. The energies involved in polishing in conventional chemical mechanical polishing, excluding the chemical reaction, are the relative movement speed of the mutually rotating carrier and platen, and the contact pressure between the substrate to be processed and the pad. In the present invention, in addition to these conventional polishing mechanisms, ultrasonic vibration is applied as a new polishing energy source. Thereby, the polishing rate can be increased without forcibly increasing the relative speed or the contact pressure.

By applying ultrasonic vibration during the polishing step, the slurry can be efficiently spread over the minute gap between the substrate to be processed and the pad. In addition, since this effect is less affected by the area of the step protrusions and the density, a uniform and good flat surface independent of the pattern can be obtained.

Further, a configuration is provided in which the amplitude and frequency of the ultrasonic vibration are changed stepwise or continuously during the polishing step, thereby changing the vibration mode applied to the substrate to be processed and avoiding the influence of the standing wave. If employed, a uniform polishing effect can be ensured. Further, it is also possible to selectively use the amplitude of the applied ultrasonic wave in the bulk polishing step in which the polishing rate is high in the initial or middle stage of the polishing and in the micro polishing step in which the polishing surface shape is prioritized in the final stage of polishing.

When the ultrasonic waves are applied intermittently during the polishing step, the polished slurry used during the application of the ultrasonic waves is
It is discharged from the minute gap between the substrate to be processed and the pad while no ultrasonic wave is applied, and is replaced with a new slurry. Therefore, polishing with fresh slurry is always possible, and pattern dependency and the microloading effect of polishing can be suppressed, and more precise chemical mechanical polishing can be performed.

Another point of the present invention resides in that an ultrasonic vibration applying means and a control means of the ultrasonic vibration applying means are mounted on a chemical mechanical polishing apparatus. The ultrasonic vibration applying means is mounted on a carrier of the substrate to be processed or a platen on which a pad is mounted so that the ultrasonic vibration can be applied to the substrate to be processed most efficiently. Can be achieved.
In addition, if the optimal ultrasonic application program corresponding to the type of the substrate to be processed is input to the control unit of the ultrasonic vibration applying unit, uniform chemical mechanical polishing can always be performed under the optimal ultrasonic vibration application conditions. Becomes

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, before describing the actual polishing process, the chemical mechanical polishing apparatus of the present invention will be described.

FIG. 2 is a schematic sectional view showing an example of the configuration of the chemical mechanical polishing apparatus of the present invention. Since the basic configuration is the same as that of the conventional chemical mechanical polishing apparatus shown in FIG. 4, the description of the overlapping parts will be omitted. Characteristic parts of the chemical mechanical polishing apparatus of the present invention include a first ultrasonic vibration applying means 18 for exciting the carrier 12 to which a substrate to be processed is attached, a first ultrasonic oscillator 20 for driving the same, and a polishing plate. In that a second ultrasonic vibration applying means 19 for exciting the platen 13 and a second ultrasonic oscillator 21 for driving the same are added. Also, the first ultrasonic oscillator 20 and the second
A feature of the chemical mechanical polishing apparatus of the present invention is that a control means 22 of an ultrasonic vibration applying means is added at the preceding stage of the ultrasonic oscillator 21. Control means 2 for ultrasonic vibration applying means
2 is a first ultrasonic oscillator 20 and a second ultrasonic oscillator 2
1 can be controlled individually or simultaneously.

The control means 22 of the ultrasonic vibration applying means can arbitrarily control the output level, output frequency and output waveform of the first ultrasonic oscillator 20 and the second ultrasonic oscillator 21. Although the output waveform is generally a sine wave, a rectangular wave, a sawtooth wave, or the like may be selected according to the purpose. Process factors such as an output level, an output frequency, and an output waveform are determined in advance by carrying out experiments on optimum conditions for each substrate to be processed, and this data is input to the control means 22 of the ultrasonic vibration applying means, and based on the input data. It is desirable to control the actual process. The control device has other factors, such as the number of revolutions of the carrier 12 and the platen 13,
By inputting optimum values such as the contact pressure between the substrate 11 and the pad 14, the pH of the slurry 17, the concentration, and the temperature conditions, automation of the entire process can be achieved.

Embodiment 1 This embodiment is an example in which the present invention is used for flattening an interlayer insulating film formed on an Al-based metal wiring, which is shown in FIGS.
This will be described with reference to FIG. Incidentally, portions having the same functions as those in FIG 3 that were subjected to the description of the conventional chemical mechanical polishing method (a) ~ (d) shall be denoted by the same reference numerals.

First, as shown in FIG. 1A, a first interlayer insulating film 1 such as SiO ₂ and a wiring layer 2 made of an Al-based metal or the like are formed on a semiconductor substrate (not shown) such as Si. .
The wiring layer 2 has a distribution in pattern density and wiring width. The line and space of the dense part of the wiring layer 2 is 0.35 μm as an example, and that of the sparse part is 2.0 μm. Each of the wiring layers has a height of 0.5 μm. Next, the second interlayer insulating film 3 is formed thick by plasma CVD, low pressure CVD, or the like, for example, to a thickness of 0.8 μm in a flat portion.
The sample formed so far is used as a substrate to be processed.

Next, using the chemical mechanical polishing apparatus shown in FIG. 2, the above-mentioned substrate 11 to be processed is stuck downward on the carrier 12 using wax or the like, and the platen 13 is excited while being excited under the following conditions as an example. The chemical mechanical polishing of the second interlayer insulating film 3 was performed. As a slurry, silica fine particles were converted to KOH.
A general suspension suspended in a / alcohol / water-based solvent was used. Platen rotation speed 50 rpm Carrier rotation speed 17 rpm Polishing pressure 8 psi Pad temperature 30-40 ° C. Slurry flow rate 225 ml / min Ultrasonic output 300 W (output of second ultrasonic oscillator) Ultrasonic frequency 40 kHz (second ultrasonic wave) Sound wave frequency)

As a result, as shown in FIG. 1B, the second interlayer insulating film 3 was flatly chemically and mechanically polished. The polishing rate is about twice as high as that of the conventional method without applying ultrasonic waves.
The pattern density dependence of the underlying wiring layer 2 was hardly measured, and a uniform flat surface was obtained. Polishing of the second interlayer insulating film is completed on the wiring layer, leaving a thickness of, for example, 0.2 μm. If necessary, an insulating film is further added by plasma CVD, low pressure CVD, or the like to form an upper wiring. . According to this embodiment, in addition to the conventional chemical mechanical polishing method, by exciting the second ultrasonic vibration applying means built in the platen, good results can be obtained in both the polishing rate and the flatness of the polished surface. did it.

Embodiment 2 In Embodiment 1, the ultrasonic vibration was continuously applied to the platen 13. In this embodiment, the substrate to be processed and other polishing conditions were the same as in Embodiment 1, and the ultrasonic vibration was applied. A method of intermittent application was adopted. As an example, when the application of ultrasonic vibration to the platen 13 was performed in a cycle of ON for 10 seconds and OFF for 10 seconds, the polishing speed was about 1.5 times as compared with the conventional method in which no ultrasonic wave was applied. The pattern density dependence of the wiring layer 2 was hardly measured, and an extremely uniform flat surface was obtained.

Embodiment 3 This embodiment is an example in which ultrasonic vibration is applied to the carrier 12 using the same substrate to be processed and the chemical mechanical polishing apparatus as in the previous embodiment. The description overlapping with the above embodiment is omitted, and only an example of the polishing conditions is described below. Platen rotation speed 50 rpm Carrier rotation speed 17 rpm Polishing pressure 8 psi Pad temperature 30-40 ° C. Slurry flow rate 225 ml / min Ultrasonic power 300 W (first ultrasonic oscillator output) Ultrasonic frequency 50 kHz (first supersonic wave) Sound wave frequency)

As a result, as shown in FIG. 1B, the second interlayer insulating film 3 was flatly chemically and mechanically polished. Polishing rate is about 2.5 times compared to the conventional method without applying ultrasonic waves.
The pattern density dependence of the underlying wiring layer 2 was hardly measured, and a uniform flat surface was obtained. Polishing of the second interlayer insulating film is completed while leaving a thickness of 0.2 μm on the wiring layer. If necessary, an insulating film is further added by low-pressure CVD or the like to form an upper wiring. According to this embodiment, in addition to the conventional chemical mechanical polishing method, the first ultrasonic vibration applying means built in the carrier 13 is excited to obtain good results in both the polishing rate and the flatness of the polished surface. Was completed. In the present embodiment, the substrate to be processed is excited by the first ultrasonic vibration applying means located very close to the substrate to be processed, so that the effect of applying ultrasonic vibration can be further improved.

Embodiment 4 In Embodiment 3, the ultrasonic vibration was continuously applied to the carrier 12, but in this embodiment, the substrate to be processed and other polishing conditions were not applied.
3 and the ultrasonic vibration intermittently
2 was applied. Carrier 12 as an example
When the application of ultrasonic vibration to the substrate was performed in a cycle of ON for 10 seconds and OFF for 10 seconds, the polishing rate was about 2.0 times as compared with the conventional method in which ultrasonic waves were not applied. The pattern density dependence was hardly measured, and a very uniform flat surface was obtained.

Embodiment 5 This embodiment is an example in which ultrasonic vibration is applied to both the carrier 12 and the platen 13 using the same substrate to be processed and the chemical mechanical polishing apparatus as in the previous embodiment. The description overlapping with the above embodiment is omitted, and only an example of the polishing conditions is described below. Platen rotation speed 50 rpm Carrier rotation speed 17 rpm Polishing pressure 8 psi Pad temperature 30-40 ° C. Slurry flow rate 225 ml / min Ultrasonic output 150 W (first ultrasonic oscillator output) Ultrasonic frequency 50 kHz (first ultrasonic Ultrasonic oscillator frequency) Ultrasonic output 200 W (Second ultrasonic oscillator output) Ultrasonic frequency 40 kHz (Second ultrasonic oscillator frequency)

As a result, as shown in FIG. 1B, the second interlayer insulating film 3 was flatly chemically and mechanically polished. Polishing rate is about 3.0 compared to the conventional method without applying ultrasonic waves.
The pattern density dependence of the underlying wiring layer 2 was hardly measured, and a uniform flat surface was obtained. Polishing of the second interlayer insulating film is completed while leaving a thickness of 0.2 μm on the wiring layer. If necessary, an insulating film is further added by low-pressure CVD or the like to form an upper wiring. According to the present embodiment, in addition to the conventional chemical mechanical polishing method, by exciting the first ultrasonic vibration applying means built in the carrier 13, good results can be obtained in both the polishing rate and the flatness of the polished surface. Was completed. According to this embodiment, by exciting both the carrier 12 and the platen 13, more efficient polishing can be performed as compared with the previous embodiment.

Although the present invention has been described with reference to the five embodiments, the present invention is not limited to these embodiments.

The ultrasonic wave may be a sine wave , a rectangular wave, a sawtooth wave, or a composite wave thereof. The applied frequency basically employs an ultrasonic wave of several tens of kHz to several hundreds of kHz.
A megasonic band on the order may be used. A plurality of frequencies may be superimposed, and excitation by white noise or pink noise is also possible.

Although the ultrasonic vibration applying means employs a configuration in which either the carrier or the platen is excited, or simultaneously, the ultrasonic vibration applying means may be configured to excite the rotation axis of the carrier or the rotation axis of the platen. Basically, the polishing speed can be improved by reducing the vibration attenuation by bringing the ultrasonic vibration applying means close to the substrate to be processed.

The planarization of an interlayer insulating film made of SiO ₂ of a semiconductor device as a substrate to be processed has been exemplified.
Silicate glass such as G, BPSG, AsSG or SiO
The insulating film such as N, Si ₃ N ₄ may be flattened. Further, the present invention may be applied to isolation between elements or flattening of a trench forming a capacitor cell of a DRAM with an insulating material or a dielectric material. Further, it may be used for flattening after forming a high melting point metal layer such as W or CVD or after forming an Al-based metal layer. The chemical mechanical polishing apparatus of the present invention can be used for mirror polishing of a semiconductor substrate or the like that does not involve a chemical reaction.

The illustrated combination of the silica fine particles and KOH / ethanol / aqueous solvent as a slurry but, A1 ₂ O ₃
Other abrasive fine particles or another type of solvent may be selected according to the substrate to be processed. For example, H ₂ O ₂ is used for flattening the W layer.
/ Solvent KOH system to be suitable, the flattening of the Al-based metal layer may be used _{H 3 PO 4 / H 2 O} 2 based solvents.

[0038]

As is apparent from the above description, according to the present invention, the ultrasonic vibration is applied to the substrate to be processed at the time of chemical mechanical polishing, which is about one time smaller than the conventional chemical mechanical polishing method. The polishing rate can be improved by a factor of at least 0.5. Since this effect can be achieved without forcibly increasing the rotation speed of the carrier and the platen and the polishing pressure, damage to the substrate to be processed is small.

Further, unevenness of the polishing rate due to the density of the pattern to be flattened and the size of the area to be flattened on the surface of the substrate to be processed is eliminated, and a good uniform flat surface can be obtained.

The above-described uniform and high-throughput chemical mechanical polishing method is achieved by employing a chemical mechanical polishing apparatus in which an ultrasonic wave applying means is added to a carrier as a support member of a substrate to be processed and a platen as a polishing plate. Since the composition of the slurry and the like may be the same as before, the effect can be enjoyed relatively easily.

With the above effects, the improvement of the throughput and the uniformity of the process of flattening the surface of a semiconductor device having a high step due to the adoption of the multilayer wiring structure are simultaneously achieved, and the present invention is highly integrated. The effect of contributing to the manufacturing process of semiconductor devices and the like is extremely large.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic cross-sectional views illustrating a chemical mechanical polishing method of the present invention, wherein FIG. 1A shows a state in which a step occurs in an interlayer insulating film formed on a plurality of wiring layers, and FIG. Is a flattened state.

FIG. 2 is a schematic sectional view showing a chemical mechanical polishing apparatus of the present invention.

3A and 3B are schematic cross-sectional views illustrating a conventional chemical mechanical polishing method, in which FIG. 3A shows a state in which a step occurs in an interlayer insulating film formed on a plurality of wiring layers, and FIG. A state in which a resist pattern is formed on the stepped recess, (c) a state in which the stepped part of the interlayer insulating film is removed by etching using the resist pattern as a mask, and (d) a state in which the interlayer insulating film is flattened by chemical mechanical polishing. It is.

FIG. 4 is a schematic sectional view showing a conventional chemical mechanical polishing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first interlayer insulating film 2 wiring layer 3 second interlayer insulating film 4 resist pattern 11 substrate to be processed 12 carrier 13 platen 14 pad 15 slurry supply system 16 nozzle 17 slurry 18 first ultrasonic vibration applying means 19 second Ultrasonic vibration applying means 20 first ultrasonic oscillator 21 second ultrasonic oscillator 22 control means for ultrasonic vibration applying means

Claims (8)

(57) [Claims] 1. A chemical mechanical polishing method comprising a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the substrate is subjected to chemical mechanical polishing while applying ultrasonic waves to the substrate. A chemical mechanical polishing method characterized in that the amplitude of ultrasonic waves is changed stepwise during the chemical mechanical polishing step. 2. A chemical mechanical polishing method having a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the substrate is subjected to chemical mechanical polishing while applying ultrasonic waves. A chemical mechanical polishing method characterized by continuously changing the amplitude of an ultrasonic wave during a chemical mechanical polishing step. 3. A chemical mechanical polishing method comprising a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the substrate is subjected to chemical mechanical polishing while applying ultrasonic waves to the substrate. A chemical mechanical polishing method characterized by gradually changing an ultrasonic frequency during a chemical mechanical polishing step. 4. A chemical mechanical polishing method comprising a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the chemical mechanical polishing is performed while applying ultrasonic waves to the substrate to be processed. A chemical mechanical polishing method characterized by continuously changing an ultrasonic frequency during a chemical mechanical polishing step. 5. A chemical mechanical polishing method comprising a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the substrate is subjected to chemical mechanical polishing while applying ultrasonic waves to the substrate. A chemical mechanical polishing method characterized by simultaneously applying ultrasonic waves of a plurality of frequencies during the chemical mechanical polishing step. 6. A chemical mechanical polishing method having a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the chemical mechanical polishing is performed while applying ultrasonic waves to the substrate to be processed. A chemical mechanical polishing method characterized by intermittently applying ultrasonic waves during the chemical mechanical polishing step. 7. A chemical mechanical polishing apparatus for flattening a surface of a substrate having a step by chemical mechanical polishing, comprising: means for applying ultrasonic vibration to the substrate to be processed; The apparatus further includes control means, wherein the control means continuously or stepwise changes in the amplitude or frequency of the ultrasonic wave applied by the ultrasonic vibration applying means,
A chemical mechanical polishing apparatus characterized in that the ultrasonic vibration applying means performs one of simultaneous application of ultrasonic waves of a plurality of frequencies and intermittent application of ultrasonic waves. 8. A method of manufacturing a semiconductor device including a step of flattening a surface of a substrate having a step by chemical mechanical polishing, wherein the substrate is subjected to chemical mechanical polishing while applying ultrasonic waves to the substrate. during chemical mechanical polishing step, continuous or stepwise variation of the ultrasonic wave amplitude or frequency applied, simultaneous application of ultrasound of a plurality of frequencies, to carry out one of the intermittent application of ultrasound A method for manufacturing a semiconductor device.