JPH10180616A - Polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of residual foreign matters on the machined surface of a workpiece while holding both polishing efficiency and machined surface accuracy on higher levels. SOLUTION: A double-layered tank stores in one of its tank chambers 5a a normal abrasive 8a mixed with abrasive grains of elevated solid phase reactivity to a workpiece A, and in the other tank chamber 5b a finishing abrasive 8b mixed with abrasive grains of elevated solid phase reactivity to the workpiece A and with a surfactant of the same polarity as the abrasive grains. According to control commands from a CNC device 7, an abrasive feed mechanism 11 switches the abrasive to be fed to the machining surface 2a of a polishing pad 2 from the normal abrasive 8a to the finishing abrasive 8b at appropriate timing in the polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for planarizing an interlayer insulating film and a metal film of a multilayer wiring.

[0002]

_2. Description of the Related Art An ECR plasma CVD method using plasma generated by cyclotron resonance of electrons has been proposed as a technique for realizing an improvement of a flattening technique of an interlayer insulating film (SiO ₂ ) which is a main problem in a multilayer wiring technique. Pyrolysis methods and other methods utilizing the thermal decomposition of organooxysilane (TEOS) have been developed. However, it is difficult to completely suppress the unevenness generated on the interlayer insulating film at the step portion of the wiring having a high aspect ratio only by introducing such a technique. Therefore, in a general multilayer wiring process, a CMP (Chemica) is generally used to polish the surface of the interlayer insulating film using an abrasive having high solid phase reactivity with the interlayer insulating film.
By adopting a planarization process that combines the above-described technology with the above-described technology, unevenness on the surface of the interlayer insulating film is removed, and the formation of a contact hole formation defect in the contact hole formation process and the pattern in the exposure process are performed. The occurrence of defects is avoided.

In a general multi-layer wiring process, foreign substances (mainly SiO ₂ abrasive grains contained in a polishing liquid) attached to the surface of a wafer in a planarization process are usually removed. In addition, a wafer cleaning process that combines physical cleaning with pure water and chemical cleaning with ammonia and hydrogen peroxide has been introduced.

On the other hand, as a technique for realizing the improvement of the metal wiring flattening technique, which is a major problem in the multilayer wiring technique as well as the above-mentioned improvement of the interlayer insulating film flattening technique, tungsten is selectively provided only in the contact hole. A selective CVD method for embedding a film has been developed. However, the tungsten film buried in the contact hole by the selective CVD method has severe surface irregularities, and it has been necessary to finish the tungsten film in a good state suitable for multilayer wiring by some method. In addition, it is necessary to remove an unnecessary tungsten film which has been grown with micro defects on the interlayer insulating film as nuclei. Therefore, introduction of CMP into a metal wiring flattening process is being studied.

[0005]

However, the conventional CM
P has two contradictory drawbacks: if the focus is on improving the polishing efficiency, the accuracy of the finished surface will decrease, and if the focus is on improving the accuracy of the finished surface, the polishing efficiency will decrease. is there. However, it is not advisable to sacrifice either one of them, and it is currently an important task to achieve both improvement in polishing efficiency and improvement in finished surface accuracy.

Further, even after a wafer cleaning process,
In the planarization process, a considerable number of SiO ₂ abrasive grains (about 20 to 100 for a 6-inch wafer) attached to the surface of the wafer cannot be completely removed and often remain on the surface of the wafer as it is. SiO remaining on the surface of this wafer
_{(2) Since the} abrasive grains are highly likely to induce appearance defects that account for most of the LSI characteristic defects, from the viewpoint of improving the yield,
It is required to take effective measures to reduce the residual SiO ₂ abrasive grains on the surface of the wafer. In spite of these demands being increasing, there has been a tendency in the past to focus only on improving the throughput of the production line.

Accordingly, the present invention provides a high precision finished surface,
In addition, it is an object of the present invention to provide a polishing apparatus and a polishing method capable of efficiently creating a finished surface having a high foreign matter removing effect by cleaning.

[0008]

In order to solve the above-mentioned problems, the present invention provides a polishing liquid supply means for supplying a polishing liquid containing abrasive grains between a workpiece and a polishing tool; A polishing apparatus, comprising: a pressurizing unit that applies a polishing pressure between the workpiece and a moving unit that slides the workpiece and the polishing tool, wherein a polishing liquid supplied by the polishing liquid supply unit is provided. A dispersant adding means for adding a dispersant for dispersing abrasive grains in the polishing liquid, an amount of the dispersant added by the dispersant adding means, and a magnitude of a polishing pressure given by the pressurizing means. A polishing apparatus, comprising:

According to the present polishing apparatus, the processing mode can be switched during the polishing process by controlling the magnitude of the polishing pressure during the polishing process and the amount of the dispersant added to the polishing liquid in a stepwise manner. Therefore, for example, by setting the dead weight state and starting the addition of the dispersant to the polishing liquid at an appropriate timing during the polishing process, the polishing process that emphasizes the mechanical polishing operation and the chemical polishing operation can be performed. The finish polishing process that emphasizes the above can be continuously executed. Thereby, a good finished surface can be created without lowering the polishing efficiency.

[0010] Then, at the stage when the process is shifted to the final polishing process, the dispersant is added to the polishing liquid, whereby an effect is obtained that the abrasive grains contained in the polishing liquid hardly adhere to the surface of the workpiece. You can also. The reason is that since the dispersant having a small surface energy is adsorbed on the abrasive grains, the energy state of the abrasive grains is more stabilized when the dispersant is dispersed in the liquid than when it is present on the surface of the workpiece. In addition, since the dispersant is also adsorbed on the abrasive particles remaining on the finished surface for some reason, in the subsequent cleaning process, the abrasive particles are quickly separated from the surface of the workpiece and dispersed in the cleaning liquid. . And it hardly reattaches to the surface of the workpiece.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the basic configuration of the polishing apparatus according to the present embodiment will be described with reference to FIG.

The present polishing apparatus includes a polishing platen 1 on which a polishing pad (a synthetic resin such as a hard foamed polyurethane) is adhered.
A tool shaft rotating mechanism 13 for rotating the tool shaft 9 to which the polishing platen 1 is attached; a spindle rotating mechanism 16 for rotating the spindle 10 to which the vacuum chuck 4 is mounted; and a work surface 2 a of the polishing pad 2. An abrasive supply mechanism 11 for supplying two types of abrasives 8a and 8b thereon, a feed mechanism 14 for moving a polishing head 15 containing a main shaft 10 in the x direction, and a main shaft 10 being moved in and out of the polishing head 15 in the z direction. A cutting mechanism (not shown) and a work A on the work surface 2a of the polishing pad 2.
And a CNC device 7 for controlling each mechanism. Hereinafter, each mechanism will be described.

The tool rotating mechanism 13 includes a servo motor 13a
Is transmitted to the tool shaft 9 via the speed reducer 13b to rotate the tool shaft 9. The rotation angle of the servo motor 13a is numerically controlled by the CNC device 7. Further, the speed of the servomotor 13a is controlled by a speed controller so as to suppress the fluctuation of the rotation speed of the tool shaft 9.

The spindle rotating mechanism 16 rotates the spindle 10 by transmitting the output of the servo motor 16a to the spindle 10 via the reduction gear 16b. The rotation angle of the servo motor 16a is numerically controlled by the CNC device 7. Further, the speed of the servo motor 16a is controlled by a speed controller so that the fluctuation of the rotation speed of the spindle 10 is suppressed.

The feed mechanism 14 includes a servo motor 14
The output of a is transmitted to the spline formed on the ball screw (not shown) for feeding the polishing head via the speed reducer 14b, thereby moving the polishing head 15 in the x direction.
The rotation angle of the servo motor 14a is numerically controlled by the CNC device 7.

Further, the cutting mechanism transmits the output of the servo motor to the quill for adjusting the spindle in / out position,
The spindle 10 is moved in and out of the polishing head 15. The rotation angle of the servo motor is numerically controlled by the CNC device 7. During the polishing process, a stopper provided inside the polishing head 15 restrains the spindle access adjustment quill, the axial position of the spindle 10 is maintained, and the workpiece A
The amount of incision given to is maintained.

Further, the Air Back type pressurizing mechanism fills a bag packed in the vacuum suction type chuck 4 with a gas (for example, N ₂ , air, etc.) supplied from an external compressor, and The work A is pressed against the work surface 2 a of the polishing pad 2 by applying a pressing force to the back surface of the work A mounted on the suction chuck 4. And
The opening of a valve attached to a flow path connecting the compressor and the bag is numerically controlled by a CNC device 7. In addition, here, the Air Back type pressurizing mechanism for filling the gas inside the bag inside the vacuum suction type chuck 4 is used, but it is not always necessary to use this.
Instead of the Air Back type pressurizing mechanism, for example, a Wat for filling a bag inside the vacuum suction type chuck 4 with liquid.
An er Back type pressurizing mechanism may be used.

The abrasive supply mechanism 11 opens one of the flow paths 12a and 12b connecting between the tank chambers 5a and 5b of the two-layer tank and the nozzle 12A,
Further, by driving the pump with a motor, the abrasives 8a and 8b stored in one of the tank chambers 5a and 5b of the two-layer tank are discharged from the nozzle 12A. The valve 6a attached to the supply pipe 12
Is numerically controlled by the CNC device 7. Then, in one tank chamber 5a of the two-layer tank, an abrasive 8a containing abrasive grains rich in solid-phase reactivity with the workpiece A is provided.
(Hereinafter, usually referred to as an abrasive 8a), and the other tank chamber 5b contains abrasive grains having a high solid phase reactivity with the workpiece A and a surfactant having the same polarity as the abrasive grains. Is stored (hereinafter, referred to as finishing abrasive 8b). When polishing a Si wafer,
An alkaline solution in which about 10% by weight of SiO ₂ abrasive having a particle size of about 37 nm is suspended is usually used as an abrasive 8a,
It is desirable to use the normal abrasive 8a to which an anionic surfactant is added as the finishing abrasive 8b. When polishing a metal film, the particle size is about 37 nm.
An acidic solution in which about 10% by weight of alumina abrasive grains are suspended is usually used as a polishing agent 8a, and a mixture of this normal polishing agent 8a and a cationic surfactant is used as a finishing polishing agent 8b. Is desirable. Further, in the present embodiment, the finishing abrasive 8b containing the optimum amount of the surfactant determined based on the experimental results is used, but the optimum amount of the surfactant is determined. It will be described later together with the experimental results used as the basis. And
By the rotation of the magnetic stirrer provided inside each of the tank chambers 5a and 5b, the normal abrasive 8a and the finishing abrasive 8b are constantly stirred at a stirring speed of about 20 rpm to 400 rpm.

Next, control processing executed by the CNC device 7 during polishing will be described. However, here,
It is assumed that the rotation of the polishing platen has started and the mounting of the workpiece A on the vacuum chuck 4 has been completed.

First, the CNC device 7 includes the abrasive supply mechanism 1
The supply of the normal abrasive 8a by the abrasive supply mechanism is started by controlling the first valve 6a and the pump. Specifically, the flow path 12a connecting the tank chamber 5a of the two-layer tank and the nozzle 12A is opened, and further, the pump is driven by the motor, and the work surface of the polishing pad 2 by the polishing agent supply mechanism 11 is operated. The release of the normal abrasive 8a toward 2a is started.

After that, the CNC device 7 controls the servomotor of the cutting mechanism to control the work A by the cutting mechanism.
Initiate the incision movement of the Air Back
By controlling the valve of the air pressure type pressurizing mechanism, the application of the polishing load by the Air Back type pressurizing mechanism is started. Specifically, the spindle 10 is extruded from the polishing head 15, and a predetermined amount of cut is given to the workpiece A from the work surface 2 a of the polishing pad 2, and gas is filled in the bag inside the vacuum suction type chuck 4. Then, a set polishing pressure is generated between the work surface 2a of the polishing pad 2 and the workpiece A.

Thereafter, the CNC device 7 controls the servo motor 14a of the feed mechanism 14 to start the feed motion of the polishing head 15 in the x direction.

The work surface 2a of the polishing pad 2 and the workpiece A are slid while applying an appropriate polishing pressure in this manner, so that the surface of the workpiece A has abrasive grains usually contained in the abrasive 8a. The cutting edge can act positively. Therefore, while maintaining such a state, it is possible to perform polishing processing with high polishing efficiency.

The CNC device 7 measures an elapsed time from the time when the polishing process is started by such a series of processes. When the predetermined polishing time elapses, the valve 6a and the pump of the abrasive supply mechanism 11 are controlled so that the finishing abrasive 8b by the abrasive supply mechanism 11 is controlled.
Is started, and the valve of the Air Back type pressurizing mechanism is controlled to terminate the polishing load by the Air Back type pressurizing mechanism. Specifically, a flow path 12b connecting between the tank chamber 5b of the two-layer tank and the nozzle 12A is opened, and further, a pump is driven by a motor, and the working surface of the polishing pad 2 by the polishing agent supply mechanism 11 is operated. The release of the finishing abrasive 8b toward 2a is started. On the other hand, the gas filled in the bag inside the vacuum suction type chuck 4 is released, and the polishing pressure applied between the work A and the work surface 2a of the polishing pad 2 is released. .

By thus sliding the work surface 2a of the polishing pad 2 and the workpiece A without applying a polishing pressure, chemical polishing of the abrasive grains contained in the finishing abrasive 8b is performed. The action positively acts on the surface of the workpiece A. Therefore, while maintaining this state,
Only the very thin damaged layer provided by the mechanical polishing action of the abrasive cutting edge can be completely removed.

The CNC device 7 measures the elapsed time from the time when the final finishing process is started by such a series of processes. Then, after the set final finishing time has elapsed, the abrasive supply mechanism 11, the cutting mechanism, and the feed mechanism 14 are returned to the initial state, and the polishing is completed.

By the control processing of the CNC device 7, the surface of the workpiece A can be continuously subjected to the polishing processing with emphasis on the mechanical polishing action and the final finishing processing with emphasis on the chemical polishing action. Therefore, a reduction in the total polishing efficiency can be prevented by the polishing performed first, and the level of the final finished surface accuracy is also guaranteed by the final finishing performed later.

Further, since the finishing abrasive 8b used in the final finishing step contains a surfactant having a dispersing action, it is better than the case where the normal abrasive 8a is used. In addition to the usual effect that a finished surface can be created, it is possible to obtain an effect that abrasive grains hardly adhere to the surface of a workpiece. that is,
Because the surface active substance having a small surface energy is adsorbed on the abrasive grains, the energy state of the abrasive grains is more stabilized when dispersed in a liquid than when present on the surface of the workpiece A. is there.

Further, since the surface active substance is also adsorbed on the abrasive particles remaining on the finished surface at this time, if the work A is thereafter washed, the abrasive particles remaining on the finished surface are promptly removed. Separates from the finished surface and disperses in the cleaning solution. And there is almost no redeposition on the finished surface. Therefore,
Extremely high foreign matter removal effect by washing.

It should be noted that it is easily confirmed that such an effect is obtained by using the above two types of abrasives continuously, based on the results of a comparative experiment performed under the following conditions. can do. Here, it is assumed that a 6-inch Si wafer having a surface on which an interlayer insulating film is formed is to be polished.

[Polishing Conditions Common to All Machining Cases] Rotational angular speed of tool shaft 20 rpm to 30 rpm Rotational angular speed of main shaft 20 rpm to 30 rpm Temperature of polishing platen 25 ° C. to 30 ° C. Feed rate of workpiece 2 mm / sec to 5 mm / sec Abrasive supply rate 50 cc / min to 200 cc / min Initial polishing pressure 500 kgf / cm2 to 800 kgf / cm2 Final finishing polishing pressure About 0 kgf / cm2 Polishing processing time Total about 10 minutes Final finishing processing time About 30 seconds to 1 minute Abrasive Condition of (A) Only normal abrasive 8a containing about 10% by weight of SiO ₂ abrasive grains is used.

(B) Normal abrasive 8a and about 0.05% by weight
Finishing abrasive 8b to which an anionic surfactant is added
And are used continuously.

As a result, as shown in FIG. 2, (A) the case where only the normal abrasive 8a is used and (B) the case where the normal abrasive 8a and the finishing abrasive 8b are used continuously, most differences with respect to the polishing efficiency did not occur, it was found that remarkable differences occur with respect to the surface roughness R _max of the surface finish. Specifically, when only (A) the normal abrasive 8a was used, the surface roughness R _max of the finished surface was at most about 2 nm, whereas (B) the normal abrasive 8a When the finishing abrasive 8b was used continuously, the surface roughness R _max of the finished surface was suppressed to about 0.7 nm. Comparing the two results, it was found that the regular abrasive 8a and the finish abrasive 8b were used continuously.
By (B), while preventing a reduction in total polishing efficiency,
At the same time, it is clear that the maintenance of the final level of finished surface accuracy has been achieved.

Also, using an optical foreign matter inspection device,
As a result of inspecting the finished surface for the presence of foreign matter (particle size 0.3 μm or more), as shown in FIG.
It has been found that there is a marked difference in the number of foreign substances adhering on the finished surface between the case where only the abrasive is used and the case where (B) the regular abrasive 8a and the finish abrasive 8b are used continuously. . Specifically, when only (A) normal abrasive 8a is used, about 20 to 100 foreign substances adhere to the 6-inch wafer surface, whereas (B) normal abrasive 8a When the finishing abrasive 8b is used continuously, 6
Only about 5 to 10 foreign substances adhered to the surface of the inch wafer. Comparing the two results, it is apparent that the continuous use of the normal abrasive 8a and the finish abrasive 8b (B) resulted in the effect of making it difficult for abrasive grains to adhere to the finished surface. It is.

After two physical cleaning processes using pure water, two chemical cleaning processes using aqueous ammonia and a drying process, foreign matter (particles) on the finished surface is measured using an optical foreign matter inspection device. As a result of re-examination of the presence or absence of a diameter of 0.3 μm or more, as shown in FIG. 4, (A) the case where only the normal abrasive 8a was used, and (B) the normal abrasive 8a and the finishing abrasive 8b It has been found that there is a marked difference in the number of foreign substances remaining on the finished surface after cleaning, when compared with the case of using the same. Specifically, (A) When only the normal abrasive 8a is used, about 5 to 5
While about 10 foreign matter still remained, (B) when the normal abrasive 8a and the finishing abrasive 8b were continuously used, almost no foreign matter was present on the surface of the 6-inch wafer. Was not remained. Comparing the two results, it is apparent that the continuous use of the normal abrasive 8a and the finishing abrasive 8b (B) has improved the foreign matter removing effect by cleaning.

By the way, such an effect cannot be achieved only by using the polishing apparatus shown in FIG.

For example, as shown in FIG. 5, a surfactant 8c is stored in one tank chamber 5f of the two-layer tank, and an abrasive 8a is normally stored in the other tank chamber 5e.
The same effect can be obtained by adjusting the finishing abrasive by mixing the normal abrasive 8a and the surfactant inside the mixing tank 5g only in the final finishing step. In this case, at the start of polishing, the CNC device 7
Controls the valve 6e of the abrasive supply mechanism 11 to open only the flow path 12e connecting the tank chamber 5e of the two-layer tank and the mixing tank 5g. Thereby, the abrasive supply mechanism 11 starts supplying the normal abrasive 8a to the inside of the mixing tank 5g. And a certain amount of the normal abrasive 8a
Is stored inside the mixing tank 5g, the CNC device 7
Further, the valve 6g of the abrasive supply mechanism 11 is controlled to open a flow path 12g connecting the mixing tank 5g and the nozzle 12A. Thereby, the abrasive supply mechanism 11 starts discharging the normal abrasive 8a toward the work surface 2a of the polishing pad 2. Then, when the set polishing time has elapsed, the CNC device 7 controls the valve 6f of the abrasive supply mechanism 11 to
The flow path 12f connecting between the tank chamber 5f of the two-layer tank and the mixing tank 5g is also opened. Thereby, the abrasive supply mechanism 11 starts supplying the surfactant 8c to the inside of the mixing tank 5g. In this way, initially, the normal abrasive 8
is supplied onto the work surface 2a of the polishing pad 2, and after the set polishing time elapses, the finishing polishing agent 8b adjusted inside the mixing tank 5g is replaced with the normal polishing agent 8a that has been supplied so far. 1 is newly supplied onto the work surface 2a of the polishing pad 2, so that, similarly to the polishing apparatus shown in FIG. 1, a polishing process that emphasizes a mechanical polishing operation and a final finish polishing process that emphasizes a chemical polishing operation. Can be executed continuously.

Alternatively, as shown in FIG. 6, a surfactant 8c is stored in one tank chamber 5c of the two-layer tank, and an abrasive 8a is usually stored in the other tank chamber 5d.
Work surface 2 of polishing pad 2 only at the stage of final finishing
The same effect can be obtained even when an appropriate amount of the surfactant 8c is directly supplied on the surface a. In this case,
CNC apparatus 7, during polishing starts, by controlling the valve 6d of the polishing agent supply mechanism 11, to open only the flow path 12d connecting between the tank chamber 5d and the nozzle 12A ₁ of a two-layer tank. Thereby, the abrasive supply mechanism 11
The release of the normal abrasive 8a toward the work surface 2a of the polishing pad 2 is started. Then, when the set polishing time has elapsed, the CNC device 7 controls the valve 6c of the polishing agent supply mechanism 11 to control the tank chamber 5c of the two-layer tank and the nozzle 12A.
Also, the flow path 12c connecting between the _two is opened. As a result, the polishing agent supply mechanism 11 moves the work surface 2a of the polishing pad 2
Also, the supply of the surfactant 8c is started. By doing so, initially, only the normal abrasive 8a is supplied onto the work surface 2a of the polishing pad 2, and after the set polishing time has elapsed, the surfactant 8c is also provided on the work surface 2a of the polishing pad 2. Since the supply is started at the same time, similarly to the polishing apparatus shown in FIG. 1, the polishing processing emphasizing the mechanical polishing action and the final finish polishing processing emphasizing the chemical polishing action can be continuously performed. In this case, unlike the polishing apparatus shown in FIGS. 1 and 5, the normal polishing agent 8a and the surfactant 8c are separately supplied onto the work surface 2a of the polishing pad 2. Work surface 2a of polishing pad 2 and workpiece A
As a result, the abrasive 8a and the surfactant 8c are almost uniformly mixed by the sliding, so that the effect of reducing the effect is hardly observed.

Finally, the optimum content of the surfactant in the above-mentioned finishing abrasive 8b will be described.

As the final finishing abrasive of the polishing apparatus shown in FIG. 1, a plurality of types of finishing abrasives having mutually different surfactant contents were experimentally used for polishing the surface of a 6-inch wafer. The effect of differences in surfactant content was studied. However, in consideration of the current situation that most of the generally used off-the-shelf abrasives contain about 10% by weight of SiO ₂ abrasive grains, here,
A finishing abrasive was prepared by adding an anionic surfactant to an abrasive containing about 10% by weight of SiO ₂ abrasive grains.

[0042] As a result, although little change in polishing efficiency even using any of the finishing abrasive was observed, the surface roughness R _max of the surface finish, type i.e. anionic finishing abrasives It was found that a change as shown in FIG. 7 was observed depending on the amount of the surfactant added. From this result, using the finishing abrasive agent added anionic surfactant in the range of about 0.01 wt% to 0.08 wt%, the surface roughness R _max of the surface finish that has the minimum value is it is obvious. On the other hand, it was also found that the number of foreign substances adhering to the finished surface changed as shown in FIG. 8 depending on the type of the finishing abrasive, that is, the amount of the anionic surfactant added. From these results, it can be seen that about 0.01% by weight to 0.0%
It is apparent that the use of the finishing abrasive to which the anionic surfactant is added in the range of 8% by weight also minimizes the number of foreign substances adhered on the finished surface. Therefore, when polishing a silicon wafer, the effect of suppressing the surface roughness _Rmax of the finished surface is the highest, and the effect of reducing the number of foreign substances adhering to the finished surface is about 0.01% by weight to 0%. It is recommended to use a finishing abrasive to which an anionic surfactant is added in the range of 0.08% by weight. In this embodiment, it is assumed that an anionic surfactant is added to an original abrasive containing about 10% by weight of SiO ₂ abrasive grains to adjust the finish abrasive, so that about 0 wt. 0.01% by weight
It is recommended to add an anionic surfactant in the range of ~ 0.08% by weight. However, when using raw abrasives having different contents of SiO ₂ abrasive grains, It is desirable to make adjustments such as adjusting the amount of addition.

A similar tendency is observed when a finishing abrasive obtained by adding a cationic surfactant to an original abrasive containing about 10% by weight of alumina abrasive grains is used for polishing the surface of a metal film. About 0.01% by weight
It is recommended to use a finishing abrasive to which a cationic surfactant is added in the range of 0.08% by weight.

[0044]

According to the polishing apparatus and the polishing method of the present invention, it is possible to efficiently create a good finished surface having a high foreign matter removing effect by cleaning. Therefore, if the present polishing apparatus is introduced into the multilayer wiring process, the yield can be improved without reducing the conventional throughput. In addition, other parts that require high shape accuracy (for example, optical elements, etc.)
It goes without saying that even if this polishing apparatus is introduced into the polishing step, the beneficial effect of efficiently creating a good finished surface can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a basic configuration of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram in which polishing solution conditions, measurement results of polishing efficiency, and measurement results of surface roughness are associated with each other.

FIG. 3 is a diagram in which a polishing liquid condition is associated with a measurement result of the number of foreign substances adhering to a finished surface.

FIG. 4 is a diagram in which polishing liquid conditions are associated with measurement results of the number of foreign substances remaining on a finished surface after cleaning.

FIG. 5 is a diagram for explaining a basic configuration of a polishing apparatus according to one embodiment of the present invention.

FIG. 6 is a diagram for explaining a basic configuration of a polishing apparatus according to an embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the amount of a surfactant added to a finishing abrasive and the finished surface roughness.

FIG. 8 is a graph showing the relationship between the amount of a surfactant added to a finishing abrasive and the number of foreign particles attached to a finished surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polishing surface plate 2 ... Polishing pad 4 ... Vacuum suction type chuck 5a, 5b, 5c, 5d, 5e, 5f ... Tank room of a two-layer tank 5g ... Mixing tank 6a, 6b, 6c, 6d, 6e, 6f, 6g: Valve 7: CNC device 8a: Normal abrasive 8b: Finishing abrasive 8c: Surfactant 9: Tool shaft 10: Main shaft 11: Abrasive supply mechanism

Continued on the front page (72) Inventor Hiroyuki Kojima 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd.Production Technology Laboratory (72) Inventor Nobuo Kayaba 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.

Claims (14)

[Claims] A polishing liquid supply means for supplying a polishing liquid containing abrasive grains between a workpiece and a polishing tool; a pressurizing means for applying a polishing pressure between the polishing tool and the workpiece; A polishing apparatus comprising: a moving unit configured to slide the workpiece and the polishing tool, wherein a dispersant for dispersing abrasive grains in the polishing liquid is added to a polishing liquid supplied by the polishing liquid supply unit. Dispersant addition means, the amount of the dispersant added by the dispersant addition means,
A polishing apparatus, comprising: a control unit that controls a magnitude of a polishing pressure given by the pressurizing unit. 2. A polishing liquid supply means for supplying a polishing liquid between a workpiece and a polishing tool; a pressurizing means for applying a polishing pressure between the polishing tool and the workpiece; What is claimed is: 1. A polishing apparatus comprising: a moving means for sliding a polishing tool; and a mixing tank for storing a polishing liquid supplied by said polishing liquid supply means while stirring, and a polishing for storing a polishing stock solution containing abrasive grains. An undiluted solution storage tank; an undiluted polishing solution supply means for supplying the undiluted polishing solution stored in the undiluted polishing solution storage tank to the mixing tank; and a dispersant storing a dispersant for dispersing abrasive grains in the undiluted polishing solution. A tank, a dispersant addition unit that adds the dispersant stored in the dispersant storage tank to the polishing liquid in the mixing tank, and an addition amount of the dispersant added by the dispersant addition unit,
The amount of the polishing stock solution supplied by the polishing stock solution supply means,
A polishing means for controlling the magnitude of the polishing pressure provided by the pressurizing means. 3. The polishing apparatus according to claim 2, wherein said pressurizing means applies a predetermined magnitude of polishing pressure until a predetermined polishing time elapses, and said dispersant adding means. Wherein the addition of the dispersant is started when the predetermined polishing time has elapsed. 4. The polishing apparatus according to claim 3, wherein the polishing stock solution is stored in the polishing stock solution storage tank as one of:
A polishing liquid containing 0% by weight of SiO ₂ abrasive grains is stored; an anionic surfactant is stored in the dispersant storage tank as the dispersant; and the control means is the predetermined polishing time. After the lapse of, the content of the dispersant in the polishing liquid in the mixing tank is about 0.0
Controlling the amount of the polishing stock solution supplied by the polishing stock solution supply unit and the addition amount of the dispersant added by the dispersant addition unit so that the amount is 1% by weight or more and 0.08% by weight or less. Characteristic polishing equipment. 5. A polishing liquid supply means for supplying a polishing liquid containing abrasive grains between a workpiece and a polishing tool, a pressurizing means for applying a polishing pressure between the polishing tool and the workpiece, A polishing apparatus comprising: a moving unit that slides the workpiece and the polishing tool, wherein a dispersant that disperses abrasive grains in the polishing liquid is supplied between the workpiece and the polishing tool. A polishing apparatus, comprising: a dispersant supply unit; and a control unit for controlling an amount of the dispersant supplied by the dispersant supply unit and a magnitude of a polishing pressure given by the pressurization unit. 6. The polishing apparatus according to claim 5, wherein the pressing means has a predetermined size between the workpiece and the polishing tool only until a predetermined polishing time elapses. When the predetermined polishing time has elapsed, the dispersant supply means starts supplying a predetermined amount of the dispersant between the workpiece and the polishing tool. Characteristic polishing equipment. 7. The polishing apparatus according to claim 6, wherein a polishing liquid containing 10% by weight of SiO ₂ abrasive grains is used as the polishing liquid, and an anionic surfactant is used as the dispersant. A polishing apparatus, wherein the dispersant supply means supplies about 0.01% to 0.08% by weight of an anionic surfactant to the polishing liquid supplied by the polishing liquid supply means. 8. A polishing agent supply means for supplying a polishing liquid between a workpiece and a polishing tool; a pressurizing means for applying a polishing pressure between the polishing tool and the workpiece; A polishing apparatus comprising: a moving means for sliding a polishing tool; and a polishing liquid supplied by the polishing agent supply means, a normal polishing liquid containing abrasive grains, and a solution having the same composition as the normal polishing liquid. A tank storing two types of polishing liquids of a finishing polishing liquid to which a dispersant for dispersing abrasive grains in the solution has been added, and a type of polishing liquid supplied by the polishing agent supply means,
A polishing means for controlling the magnitude of the polishing pressure provided by the pressurizing means. 9. A polishing apparatus according to claim 8, wherein said pressurizing means applies a predetermined polishing pressure until a predetermined polishing time elapses, and said polishing liquid supply means. Until a predetermined polishing time elapses, supply the stock solution stored in the first tank as the polishing liquid, and after the predetermined polishing time elapses, the polishing liquid is used as the polishing liquid. A polishing apparatus for supplying a finishing polishing liquid stored in two tanks. 10. The polishing apparatus according to claim 9, wherein a polishing liquid containing 10% by weight of SiO ₂ abrasive grains is used as the normal polishing liquid, and the normal polishing liquid is used as the finishing polishing liquid. A polishing apparatus characterized by using a polishing liquid obtained by adding about 0.01% by weight to 0.08% by weight of an anionic surfactant to a solution having the same composition. 11. A polishing method for polishing a workpiece by sliding the workpiece and the polishing tool while supplying a polishing liquid containing abrasive grains between the workpiece and the polishing tool. A polishing step of polishing the workpiece while applying a polishing pressure of a predetermined magnitude between the workpiece and the polishing tool until a predetermined polishing time elapses; After the elapse of the polishing processing time, while adding a dispersant for dispersing abrasive grains in the polishing liquid to the polishing liquid supplied between the workpiece and the polishing tool, the processing object and the polishing tool A finishing polishing step of polishing the workpiece without applying a polishing pressure therebetween. 12. The polishing method according to claim 11, wherein the polishing liquid contains 10% by weight of SiO ₂ abrasive particles, the dispersant is an anionic surfactant, and added in the polishing step. The amount of the dispersant to be added is about 0.01% to 0.08% by weight based on the polishing liquid
A polishing method characterized by the following. 13. A polishing method for polishing a workpiece by sliding the workpiece between the workpiece and the polishing tool while supplying a polishing liquid containing abrasive grains between the workpiece and the polishing tool. A method, wherein the workpiece is polished while applying a predetermined magnitude of polishing pressure between the workpiece and the polishing tool, and after the predetermined polishing time has elapsed, the workpiece and A polishing liquid to be supplied between the polishing tool and the polishing liquid currently being supplied, and a polishing agent for finishing in which a dispersant for dispersing abrasive grains in the solution to a solution having the same composition as the polishing liquid being supplied is added. A polishing method characterized by switching to a liquid and polishing the workpiece without applying a polishing pressure between the workpiece and the polishing tool. 14. The polishing method according to claim 13, wherein the polishing liquid contains 10% by weight of SiO ₂ abrasive grains, and the polishing liquid for finishing is about 0.01% by weight to 0.08%.
A polishing method characterized by containing not more than% by weight of an anionic surfactant.