JPH097982A - Polishing apparatus and polishing method using it - Google Patents

Abstract

PURPOSE: To ensure uniform polishing the surface of a substrate and between substrates by disposing a plurality of polishing means in which distances of rotary boars from the center are different from each other, and a radius of the rotary board covers a locus drawn on the rotary board upon polishing. CONSTITUTION: Polishing cloth 1 is sticked over a rotary board 2, and a substrate 4 of a substrate holder 5 is slidably held on the polishing cloth 1 in close contact with the same. First, second, and third polishing heads 6, 7, and 8 are disposed in order from the center of the rotary board 2 to the outer periphery of the same at a predetermined position on the upstream side of the substrate holder 5. A slurry like polishing agent 3 is supplied onto the polishing cloth 1 between the first polishing head 6 and the second polishing head 7 and between the second polishing head 7 and the third polishing head 8. The entire surface of the polishing cloth 1 is polished with the three polishing heads 6 to 8 such that a radius of the rotary board 2 covers loci T1 to T3 drawn by the bottom surface of the rotary board by the rotation of the rotary board 2. Accordingly, uniform polishing is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for performing chemical mechanical polishing, and more particularly to a polishing apparatus capable of polishing a substrate having a step with good in-plane uniformity in a manufacturing process of semiconductor devices and the like. It also relates to a polishing method using this polishing apparatus.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high integration of semiconductor devices, wiring patterns have been moving toward miniaturization and multilayering. However, when the step of the interlayer insulating film becomes large and steep due to the miniaturization and high integration of the semiconductor device, the processing accuracy and reliability of the wiring pattern formed on the interlayer insulating film are deteriorated, and the reliability of the semiconductor device itself is deteriorated. It also causes the decrease. For this reason, it is currently difficult to significantly improve the step coverage of the wiring layer made of an Al-based material mainly formed by the sputtering method. At present, it is necessary to improve the flatness of the interlayer insulating film. .

Conventionally, as a technique for flattening an interlayer insulating film, for example, a method of applying SOG (Spin On Glass),
Known methods include a method of further flattening the insulating film with a resist material and then collectively etching back these, a method of reflowing the insulating film by heat treatment, and the like.

However, even if an interlayer insulating film is formed by applying these techniques, on a wiring pattern with a wide wiring interval,
Insufficient planarization further lowers the processing accuracy and reliability of the wiring pattern formed on it, and conversely, on wiring with a narrow wiring interval, it is possible to sufficiently fill this wiring pattern with an interlayer insulating film. There was a problem that "su" was generated without doing so.

Therefore, in recent years, chemical mechanical polishing (hereinafter,
CMP. The planarization of the interlayer insulating film due to (4) has been attracting attention. In this polishing method, while the polishing agent on the slurry is supplied onto the polishing cloth stretched on the rotary platen, the surface to be polished of the wafer is brought into sliding contact with the polishing cloth to flatten the wafer. .

To perform this CMP, for example, a polishing apparatus as shown in the side view of FIG. 10 is used. This polishing apparatus mainly comprises a rotary platen 10 on which a polishing cloth 101 is stretched.
2. A polishing agent supply means 112 for supplying the polishing agent 103 onto the polishing cloth 101, and a substrate holding table 105 for closely holding a wafer (substrate) 104.

The rotary platen 102 is rotatable in the direction of arrow a by being connected to a motor (not shown) via a shaft portion 102s provided at the center thereof.

The base holding table 105 is rotatable in the direction of arrow b and connected in the direction of arrow c by being connected to a drive mechanism (not shown) through a shaft portion 105s provided at the center thereof. Is also movable, the base 1
04 can be slidably contacted with / separated from the polishing cloth 101.

In order to actually carry out the polishing by the above-mentioned polishing apparatus, first, the substrate 104 is rotated while being held by the substrate holding table 105. Further, the polishing agent 103 is supplied onto the polishing cloth 101 from the polishing agent supply means 112 while rotating the rotary platen 102. Then, the surface to be polished of the substrate 104 and the polishing cloth 101 are brought into sliding contact with each other via the polishing agent 103 to polish the substrate 104. At this time, the substrate 104 revolves by the rotation of the rotary platen 102 while rotating on its own axis by the rotation of the substrate holding table 105, so that one point on the surface to be polished of the substrate 104 is the polishing cloth 1
The locus drawn on 01 is a revolution orbit, which enables highly uniform polishing.

In such a polishing apparatus, the polishing cloth 10
A surface roughness of 1 has a great effect on polishing characteristics such as polishing rate and achievable flatness. Therefore, the polishing cloth 101
For this, a flexible material such as polyurethane is usually used after being adjusted to a desired surface roughness. However, since the polishing pad 101 is worn during polishing and changes the surface roughness, it is necessary to grind the polishing pad 101 in order to prevent the polishing characteristics from changing with time. Therefore, in the above-described polishing apparatus, the grinding head 106 in which the grinding grains 107 such as diamond are embedded is arranged, and the grinding grains 107 are slidably contacted with the polishing cloth 101 to perform grinding. . This grinding head 106
Is connected to a drive mechanism (not shown) via a shaft portion 106s provided at the center thereof, so that it can rotate in the direction of arrow d at a desired number of rotations and can also move in the direction of arrow e. The sliding contact / separation with respect to the polishing cloth 101 can be controlled.

Grinding using such a grinding head 106 may be carried out successively after a predetermined amount of polishing is completed,
In order to respond to changes in polishing characteristics during polishing, the polishing may be performed simultaneously with polishing.

[0012]

By the way, the base 104
In order to perform uniform polishing within the surface of the polishing cloth and between the substrates 104, not only the surface roughness of the polishing cloth 101 but also the polishing cloth 10
It is also necessary to appropriately control the cross-sectional shape of the No. 1 unit.

This is because when the polishing cloth 101 has an inappropriate unevenness in cross section, the substrate holding surface of the substrate holding table 105 is parallel to the upper surface of the rotary platen 102.
Even if 04 is slidably contacted with the polishing cloth 101, the pressing pressure of the base body 104 against the polishing cloth 101 varies within the surface.

Further, even if the parallelism between the substrate holding surface of the substrate holding table 105 and the surface of the polishing cloth 101 is too high, when the substrate 104 is brought into sliding contact with the polishing cloth 101, the substrate 104 becomes Slurry 103 because it adheres to 101
Cannot enter the central portion of the base 104. The slurry 10 originally existing near the center of the base 104
3 also tends to be expelled to the outer peripheral side with the rotation of the base body 104, and this is affected by a large linear velocity on the outer peripheral side. That is, even if the surface of the polishing pad 101 is too flat, the polishing rate is higher in the outer peripheral portion than in the central portion of the substrate 104, and sufficient in-plane uniformity cannot be achieved. Further, it is difficult to secure reproducibility in the polishing in which the in-plane uniformity cannot be achieved.

However, in the conventional polishing apparatus as described above, since the grinding grain holding surface of the grinding head 106 is a single plane, the cross-sectional shape of the polishing pad 101 cannot be freely controlled.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and provides a polishing apparatus capable of controlling the cross-sectional shape of a polishing cloth so that uniform polishing can be performed within a plane of a substrate and between substrates. The purpose is to provide. Another object of the present invention is to provide a polishing method using such a polishing apparatus.

[0017]

A polishing apparatus according to the present invention has been proposed in order to achieve the above-mentioned object, and includes a rotary platen on which a polishing cloth is stretched, and polishing on the polishing cloth. Holding the substrate in close contact with the polishing agent supply means for supplying the agent,
And a plurality of grinding means for grinding the polishing cloth by bringing the abrasive particles held by itself into sliding contact with the polishing cloth. The plurality of grinding means have different distances from the center of the rotary platen, and are arranged such that the locus drawn on the rotary platen during the grinding operation covers the radius of the rotary platen.

That is, the polishing apparatus of the present invention can control not only the surface roughness of the polishing cloth but also the cross-sectional shape of the polishing cloth by a plurality of grinding means.

In order to control the cross-sectional shape to a desired shape, at least one of the rotational speed, the pressing pressure on the polishing cloth, and the pressing angle of each grinding means can be controlled independently of the other grinding means. Needs to be done.

Here, in order to cover the radius of the rotary platen by the loci drawn by a plurality of grinding means, the diameter of each grinding means is equal to the radius of the rotary platen divided by the number of grinding means, or The diameter or number of grinding means may be set so as to increase. In this case, the respective grinding means are arranged so that the path drawn by each grinding means by the rotation of the rotary platen is in contact with or partially overlaps the path drawn by the adjacent grinding means. The trajectory drawn may be divided into concentric circles on the rotary platen.

Even if the diameter of each grinding means is smaller than the length obtained by dividing the radius of the rotary surface plate by the number of grinding means, each grinding means can swing in the radial direction of the rotation surface plate. If provided, the radius of the rotary platen can be covered by the locus drawn by these grinding means. In this case, in order to continuously change the grinding conditions generated on the polishing cloth in the radial direction, it is preferable that the locus drawn by each grinding means partially overlaps the locus drawn by the adjacent grinding means. The number of revolutions of each of the grinding means, the pressing pressure on the polishing cloth, and the pressing angle may be changed in synchronization with the swing.

Further, the polishing agent supply means performs the polishing uniformly and further holds the polishing agent evenly on the ground polishing cloth, so that the polishing agent is applied to one or more locations in the vicinity of the polishing means as described above. It is preferable that they are arranged so that they can be supplied.

The polishing method of the present invention is carried out by using the above-described polishing apparatus, and the polishing agent is supplied to the polishing cloth stretched on the rotary platen and held on the substrate holding table. After the surface to be polished of the substrate is brought into sliding contact with the polishing cloth, the substrate is polished, or while the polishing is being performed, the abrasive grains held by the grinding means are brought into sliding contact with the polishing cloth. When grinding the polishing cloth, the distance from the center of the rotary platen is different from each other, and
The cross-sectional shape of the polishing cloth is controlled to a desired shape by using a plurality of grinding means arranged so that the locus drawn on the rotary platen for the grinding operation covers the radius of the rotary platen. .

Here, in order to control the cross-sectional shape of the polishing cloth to a desired shape, at least one of the number of revolutions in each of the grinding means, the pressing pressure against the polishing cloth, and the pressing angle is independent of the other grinding means. It suffices to grind while controlling. Further, the grinding means may be swung in the radial direction of the rotary platen.

Further, in order to carry out the grinding uniformly and further to hold the polishing agent uniformly on the ground polishing cloth, it is preferable to supply the polishing agent to one or more places in the vicinity of the grinding means.

Any conventionally known material can be used as the grinding abrasive grains embedded in the grinding means, but diamond, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), boron nitride ( BN), titanium nitride (TiN), silicon oxide (SiO ₂ ), cerium oxide (CeO) and the like.

[0027]

By applying the present invention, a plurality of grinding means are arranged such that the distances from the center of the rotary platen are different from each other and the trajectory drawn on the rotary platen covers the radius of the rotary platen. If the grinding conditions (rotation speed, pressing pressure, pressing angle, etc.) are made different for each grinding means, the cross-sectional shape of the polishing cloth can be freely controlled.

If the grinding conditions are changed in synchronism with the swing of each grinding means, the grinding conditions can be continuously changed in the radial direction of the rotary platen. Become.

If the polishing agent can be supplied to one or more locations in the vicinity of the grinding means, the polishing agent can be uniformly supplied to each grinding means. It becomes possible to stabilize. Further, since the polishing agent can be uniformly held on the polishing cloth that has been given a predetermined surface roughness by grinding, the polishing conditions for the substrate can be stabilized.

Therefore, by using such a polishing apparatus, it becomes possible to perform uniform polishing within the plane of the substrate and between the substrates.

[0031]

EXAMPLES Hereinafter, a polishing apparatus according to the present invention and a polishing method used for the same will be described with reference to specific examples.

Example 1 The polishing apparatus of this example is provided with three grinding means so that the distances from the center of the rotary platen are different from each other. Hereinafter, the polishing apparatus will be described with reference to the side view shown in FIG. 1 and the top view shown in FIG.

In this polishing apparatus, a rotating surface plate 2 on which a polishing cloth 1 is stretched and a substrate 4 are held in close contact with each other, and a substrate holding table 5 for slidingly contacting this with the polishing cloth 1 is provided. Three grinding means (first grinding head 6, second grinding head 7, third grinding head 8) arranged in order from the center of the rotary platen 2 toward the outer peripheral portion at a predetermined point on the upstream side. And the slurry-like abrasive 3 on the polishing cloth 1 between the first grinding head 6 and the second grinding head 7 and between the second grinding head 7 and the third grinding head 8, respectively. The polishing agent supply means 12 and 13 for supplying.

Here, the rotary platen 2 is rotatable in the direction of arrow A by being connected to a motor (not shown) via a shaft portion 2s provided at the center thereof.

The substrate holding table 5 is arranged at a position where the center of the substrate 4 faces the center of the radius of the rotary platen 2. Then, by connecting to a drive mechanism (not shown) through a shaft portion 5s provided at the center thereof, the base body 4 can be rotated in the direction of arrow B and can also be moved in the direction of arrow C. It is possible to control sliding contact / separation with respect to.

The first grinding head 6, the second grinding head 7, and the third grinding head 8 each have a disk-shaped grinding means having a diameter larger than a length obtained by dividing the radius of the rotary platen 2 into three equal parts. Is. The first grinding head 6 is arranged on the innermost peripheral part of the rotary platen 2, the second grinding head 7 is arranged on the center part of the radius of the rotary platen 2, and the third grinding head 8 is provided.
Are arranged on the outermost periphery of the rotary platen 2. Note that these three
The three grinding heads 6, 7 and 8 are so arranged that the trajectories T ₁ , T ₂ and T ₃ drawn by the bottom surface thereof by the rotation of the rotary platen 2 pass over the entire surface of the polishing cloth 1, that is, the three grinding heads. 6, 7 and 8 are arranged so that the entire surface of the polishing pad 1 can be ground. However, since all three grinding heads 6, 7, and 8 cannot be lined up within the same radius, here, the second grinding head 7 is arranged more than the first grinding head 6 and the third grinding head 8. It was arranged on the upstream side.

Further, on the bottom surface of each grinding head 6, 7, 8 as shown in FIG.
Grinding abrasive grains 9, 10 and 11 each made of diamond having a grain size of 100 μm are embedded. Here, the region in which the grinding abrasive grains 9, 10, 11 are embedded is formed so as to protrude more than the other regions.

The grinding heads 6, 7 and 8 are respectively connected to drive mechanisms (not shown) via shafts 6s, 7s and 8s provided at the centers thereof, so that each of them has a desired rotation speed. And is movable in the direction of arrow E, so that the sliding contact / separation and pressing pressure of the abrasive grains 9, 10, 11 with respect to the polishing cloth 1 are controlled. Has been done. Further, each of the grinding heads 6, 7 and 8 can be tilted in the arrow F direction by the driving mechanism described above, whereby the tilt of the shaft portions 6s, 7s and 8s from the vertical direction (hereinafter, tilt angle will be described). Is called)) is adjusted.

Using such a polishing apparatus, the first grinding head 6, the second grinding head 7, and the third grinding head 8
With the rotational speed, the pressing pressure, and the tilt angle set to desired values, respectively.
11 can be brought into sliding contact with the polishing cloth 1, and the polishing cloth 1 can be made to have a desired cross-sectional shape.

Further, the polishing agent 3 is placed on the polishing cloth 1 between the first grinding head 6 and the second grinding head 7 and between the second grinding head 7 and the third grinding head 8, respectively. Since it can be supplied, the polishing agent 3 can be supplied to the respective grinding heads 6, 7, and 8 substantially uniformly. This leads to stabilization of the grinding conditions performed by the grinding heads 6, 7, and 8. Further, the abrasive 3 can be uniformly held on the polishing cloth 1 which has been given a predetermined surface roughness by grinding.

Example 2 An example in which the step of forming an interlayer flattening film in the manufacturing process of a semiconductor device is performed using the polishing apparatus of Example 1 as described above will be described below.

First, as shown in FIG. 4, a lower insulating film 52 made of silicon oxide and an Al film are formed on a silicon substrate 51.
Wiring pattern 53 made of a system material, the wiring pattern 53
A wafer having an interlayer insulating film 54 covering the above was sequentially prepared. Here, the interlayer insulating film 54 is formed under the following film forming conditions.

Film forming conditions for the interlayer insulating film 54 Source gas: TEOS flow rate 350 sccm O ₂ flow rate 350 sccm Pressure: 1330 Pa (10 Torr) Temperature: 400 ° C. RF power: 360 W However, TEOS is tetraethoxysilane. .

Then, the wafer (substrate 4) having the above-mentioned structure was polished as follows to remove the convex portions of the steps of the interlayer insulating film 54 and flatten it.

Specifically, first, the rotary platen 2 is set to 50 rp.
While rotating at m, the number of rotations of the first grinding head 6, the second grinding head 7, and the third grinding head 8, the pressing pressure to the polishing cloth 1, and the tilt angle are set as follows. The respective abrasive grains 9, 10, 11 were brought into sliding contact with the polishing cloth 1.

Setting of first grinding head 6 Rotation speed: 50 rpm Pressing pressure: 900 g / cm ² Tilt angle: 3 ° Setting of second grinding head 7 Rotation speed: 50 rpm Pressing pressure: 700 g / cm ² Tilt angle: 0 ° Setting of third grinding head 8 Rotational speed: 50 rpm Pressing pressure: 900 g / cm ² Tilt angle: -3 ° The tilt angle is the shaft portion 6 of each grinding head 6, 7, 8.
The direction of inclining s, 7s, and 8s toward the center of the rotary platen 2 is shown as plus (+), and the direction of tilting toward the outer peripheral side of the rotary platen 2 is shown as minus (-).

Then, while the abrasive 3 in the form of a slurry of silica / potassium hydroxide / water is supplied onto the polishing cloth 1 which has been ground under the above-mentioned conditions, the substrate 4 is covered with the interlayer insulating film 54. Are held by the substrate holding table 5 so as to face the polishing cloth 1 and rotated at 50 rpm so that the substrate holding surface of the substrate holding table 5 is parallel to the upper surface of the rotary platen 2. 4 was brought into sliding contact with the polishing cloth 1.

As a result, the substrate 4 was polished, and the interlayer insulating film 54 on the substrate 4 was flattened, as shown in FIG. Then, the substrate 4 was separated from the polishing cloth 1, and the surface to be polished was washed with an aqueous solution of hydrogen fluoride (HF) to remove the attached abrasive 3.

When polishing was carried out as in this example, the in-plane surface of the substrate 4 could be polished with uniform polishing characteristics. By adjusting the pressing pressure and the tilt angle in each of the grinding heads 6, 7, and 8, the cross-sectional shape of the polishing cloth 1 is relative at the center of the radius of the rotary platen 2 as shown in FIG. This is because the height is controlled to be relatively high, and the height becomes relatively lower toward the center and the outer peripheral edge of the rotary platen 2, that is, the shape in which the center of the radius rises. Specifically, the cross section of the polishing cloth 1 has a convex shape such that the center of the radius is relatively higher by 30 μm.

When the polishing cloth 1 has such a cross-sectional shape, the base body 4 held on the base body holding base 5 is
The center of the abrasive cloth 1 is pressed against a portion of the polishing cloth 1 having a relatively high height, and the outer peripheral side of the substrate 4 is pressed against a portion of the polishing cloth 1 having a relatively low height. Not only on the outer peripheral side of the base 4, but also into the center of the base 4, it is easy to enter, and the center of the base 4 can be sufficiently polished.

The polishing agent 3 is used for each of the grinding heads 6, 7, 8
The fact that the polishing cloth 1 that has been supplied from between the above and subjected to predetermined grinding is uniformly held is also one of the reasons why sufficient polishing can be performed up to the central portion of the substrate 4.

Further, when this embodiment was applied and other substrates were similarly polished, polishing with excellent reproducibility was achieved.

Embodiment 3 The polishing apparatus of this embodiment has a grinding means capable of swinging in the radial direction of a rotary platen. Hereinafter, this polishing apparatus will be described with reference to the side view shown in FIG. 7 and the top view shown in FIG. It should be noted that members having the same configurations as those of the polishing apparatus shown in Example 1 are designated by common reference numerals, and redundant description will be omitted.

In this polishing apparatus, the rotary platen 2 on which the polishing cloth 1 is stretched and the substrate 4 which holds the substrate 4 in close contact with each other and makes sliding contact with the polishing cloth 1 are the same as those in Example 1. It has the same configuration as the device.

Then, in the polishing apparatus of this embodiment,
Grinding means (first grinding head 16 and second grinding head 17) having a diameter smaller than a length obtained by dividing the radius of the rotary platen 2 into two equal parts is arranged at a predetermined point on the upstream side of the substrate holding table 5. Further, the abrasive supply means 12 is arranged so that the abrasive 3 can be supplied onto the polishing cloth 1 between the first grinding head 16 and the second grinding head 17.

The grinding heads 16 and 17 are the rotary platen 2
The first grinding head 16 and the second grinding head 17 are disposed on the same radius of the inner surface of the rotary platen 2 and the outer surface of the rotary platen 2, respectively. Also, on the bottom of each,
Similar to the grinding heads 6, 7, and 8 of Example 1, grinding abrasive grains 19 and 20 made of diamond having a grain size of 100 μm, respectively.
Is buried.

Further, the grinding heads 16 and 17 are respectively connected to a drive mechanism (not shown) via shafts 16s and 17s provided at the centers thereof, whereby the respective grinding heads 16 and 17 are rotated at a desired rotational speed in the direction of arrow D. In addition to being rotatable, it is also movable in the direction of arrow E, and the sliding contact / separation of the abrasive grains 19 and 20 with respect to the polishing cloth 1 and the pressing pressure are controlled respectively.

Further, each of the grinding heads 16 and 17 can be tilted in the direction of arrow F by the driving mechanism described above, whereby the tilt angle is adjusted. Also, arrow G
It is also possible to swing in any direction at a desired speed. Due to this swinging motion, these two grinding heads 16 and 17 are
The locus of the bottom surface covers the radius of the rotary platen 2, that is, the entire surface of the polishing pad 1 can be ground.

By using such a polishing apparatus, the first grinding head 16 and the second grinding head 17 are set in a state in which the rotational speed, the pressing pressure, the tilt angle and the swing speed are set to desired values, respectively. The abrasive grains 19 and 20 can be brought into sliding contact with the polishing cloth 1 to generate a desired cross-sectional shape on the polishing cloth 1. In addition, in each of the first grinding head 16 and the second grinding head 17, it is possible to perform grinding while synchronizing with the swing and changing the rotation speed, the pressing pressure, and the tilt angle.

Example 4 Hereinafter, an example of performing the step of forming an interlayer flattening film in the manufacturing process of a semiconductor device using the polishing apparatus of Example 4 as described above will be described.

Specifically, first, as in the second embodiment, the lower insulating film 52 and the wiring pattern 5 are formed on the silicon substrate 51.
3. The wafer (substrate 4) on which the interlayer insulating film 54 covering the wiring pattern 53 was sequentially formed was held on the substrate holder 5 so that the interlayer insulating film 54 faced the polishing cloth 1.

Further, the rotary platen 2 is rotated at 50 rpm, and the rotational speeds of the first grinding head 16 and the second grinding head 17, the pressing pressure to the polishing cloth 1, and the rocking speed are set as follows. Then, the respective grinding abrasive grains 19 and 20 were brought into sliding contact with the polishing cloth 1 in a state where the tilt angle was changed as described below in synchronization with the swing.

Setting of the first grinding head 16 Rotational speed: 50 rpm Pressing pressure: 900 g / cm ² Swinging speed: 30 times / min Tilt angle: 3 from the center of the rotary platen 2 toward the center of the radius of the rotary platen 2. Continuous change from ° to 0 ° Setting of the second grinding head 17 Rotation speed: 50 rpm Pressing pressure: 900 g / cm ² Swing speed: 30 times / min Tilt angle: Rotation constant from the radius center of the turn table 2 Board 2
It continuously changes from 0 ° to −3 ° toward the outer periphery of the first grinding head 16 and the second grinding head 17 are always oscillated in synchronization in the same direction, and the moving range of both Are so arranged that they partially overlap each other at the radius center of the rotary platen 2.

Then, while supplying the polishing agent 3 onto the polishing cloth 1 whose cross-sectional shape is controlled in this way, the substrate holding table 5 holding the substrate 4 is rotated at 50 rpm,
The substrate 4 was brought into sliding contact with the polishing cloth 1 such that the substrate holding surface of the substrate holding table 5 was parallel to the upper surface of the rotary platen 2.

As a result, the substrate 4 was polished and the interlayer insulating film 54 on the substrate 4 was flattened. After that, the substrate 4 was separated from the polishing cloth 1 and the surface to be polished was washed to remove the abrasive 3 adhering thereto.

When polishing was carried out as in this example, the in-plane surface of the substrate 4 could be polished with uniform polishing characteristics. This is because the tilt angle of the first grinding head 16 and the second grinding head 17 is changed while swinging the grinding head 16, so that the polishing cloth 1 rises at the center of the radius of the rotary platen 2. This is because the cross-sectional shape could be changed. When the cross-sectional shape of the polishing cloth 1 is controlled in this way, the polishing agent 3
Can easily enter not only the outer peripheral side of the substrate 4 but also the central portion of the substrate 4, and sufficient polishing can be performed to the central portion of the substrate 4. Further, even when polishing was performed on other substrates in the same manner, polishing with excellent reproducibility was achieved.

Although the polishing apparatus according to the present invention and the polishing method using the same have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

For example, in the polishing apparatus of Example 1,
Although the three grinding heads 6, 7 and 8 are arranged, four or more grinding heads may be arranged so that the cross-sectional shape of the polishing pad 1 can be strictly controlled. If the cross-sectional shape of the polishing pad 1 is simply a shape in which the center of the radius of the rotary platen 2 is raised, two grinding heads having a diameter larger than the length obtained by halving the radius of the rotary platen 2 are used. It is also possible to achieve this by providing each with a predetermined tilt angle.

Furthermore, in the polishing apparatus of Example 3,
A drive mechanism that can change the tilt angle while swinging is provided for the two grinding heads 16 and 17, but if the cross-sectional shape to be given to the polishing cloth 1 is determined, as shown in FIG. Is provided with a guide rail 21 at a position where the distance to the curved surface to be given to the polishing cloth 1 is equal, and the grinding heads 16 and 17 are moved along the guide rail along arrow H.
You may make it move to a direction. With such a configuration, by moving the grinding heads 16 and 17, the tilt angle can be automatically changed to a desired value, and the drive mechanism can be simplified.

Instead of changing the tilt angle, the rotation speed of the grinding heads 16 and 17 and the pressure applied to the polishing cloth 1 may be changed in synchronization with the swing. Furthermore, the cross-sectional shape of the polishing pad 1 may be controlled by changing the rocking speed itself depending on the radial position of the rotary platen 2.

Furthermore, it is possible to provide three or more grinding heads, or two or more abrasive supply pipes 12.

Further, in Examples 2 and 4, the cross-sectional shape of the polishing cloth 1 was ground so that the center of the radius of the rotary platen 2 was raised, but different cross-sections may be used as required. A shape may be formed.

In each embodiment, the grinding heads 6, 7,
8 and the bottoms of the grinding heads 16 and 17 have grinding grains 9,
Although 10, 11 and the grinding abrasive grains 19, 20 are embedded only in a part of the outer peripheral edge portion, they may be embedded over the entire outer peripheral edge portion or the entire bottom surface.

In addition, in order to simultaneously polish two or more substrates at the same time, the number of substrate holders and grinding heads is increased, or the substrates are polished and then the polishing cloth 1 is ground. To recover the cross-sectional shape, etc.
Various modifications can be made without departing from the spirit of the present invention.

The present invention is applied not only to the planarization of the interlayer insulating film but also to the inside of the groove of the embedded insulating film formed on the semiconductor substrate having the groove when forming the planarized element isolation region. It may be applied to remove other parts. It can also be applied to the formation of a silicon active layer using a bonded SOI (silicon on insulator) substrate.

[0076]

As is apparent from the above description, by applying the present invention, a plurality of grinding means are provided so that the distances from the center of the rotary platen are different from each other, and the grinding conditions are different for each grinding means. By doing so, it becomes possible to freely control the cross-sectional shape of the polishing cloth.

Therefore, when such a polishing apparatus is used, uniform polishing can be performed within the surface of the base and between the bases.

Therefore, when the present invention is applied to, for example, planarization in a semiconductor device manufacturing process, it becomes possible to manufacture a highly reliable device having a multilayer wiring structure.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a configuration example of a polishing apparatus according to the present invention.

FIG. 2 is a schematic top view of the polishing apparatus of FIG.

FIG. 3 is a schematic bottom view showing a grinding head.

FIG. 4 is a schematic cross-sectional view showing a process of flattening an interlayer insulating film to which the present invention is applied, showing a substrate in a state where an interlayer insulating film covering a wiring pattern is formed.

5 is a schematic cross-sectional view showing a state in which the substrate of FIG. 4 is polished and flattened.

FIG. 6 is a schematic cross-sectional view showing a cross-sectional shape of a polishing cloth when an example of the polishing method according to the present invention is applied.

FIG. 7 is a schematic side view showing another configuration example of the polishing apparatus according to the present invention.

8 is a schematic top view of the polishing apparatus of FIG.

9 is a schematic side view of essential parts showing a modified example of the polishing apparatus of FIG.

FIG. 10 is a schematic side view showing a configuration example of a conventional polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing cloth 2 Rotating surface plate 3 Abrasive agent 4 Substrate 5 Substrate holding table 6 First grinding head 7 Second grinding head 8 Third grinding head 9, 10, 11 Grinding abrasive grains 12 Abrasive supply pipe 51 Silicon substrate 52 lower layer insulating film 53 wiring pattern 54 interlayer insulating film

Claims (8)

[Claims] 1. A rotary surface plate on which a polishing cloth is stretched, an abrasive supply means for supplying an abrasive onto the polishing cloth, and a substrate which are held in close contact with each other and are brought into sliding contact with the polishing cloth while rotating the substrate. And a plurality of grinding means for grinding the polishing cloth by bringing the abrasive grains held by itself into sliding contact with the polishing cloth, wherein the plurality of grinding means are the rotary platen. The polishing apparatus is characterized in that the distances from the center of the rotating platen are different from each other, and the locus drawn on the rotating platen during the grinding operation is arranged so as to cover the radius of the rotating platen. 2. Each of the grinding means is capable of controlling at least one of the number of rotations, a pressing pressure against the polishing cloth, and a pressing angle independently of the other grinding means. Item 1. The polishing apparatus according to Item 1. 3. The polishing apparatus according to claim 2, wherein each of the grinding means is swingable in a radial direction of the rotary platen. 4. The polishing apparatus according to claim 1, wherein the polishing agent supply means is arranged so that the polishing agent can be supplied to one or more locations in the vicinity of the grinding means. 5. The polishing pad is stretched on a rotary platen, and the polishing agent is supplied to the polishing pad while the polishing target surface of the substrate held on the substrate holding table is brought into sliding contact with the polishing pad. After polishing, or while performing this polishing, when grinding the polishing cloth by bringing the abrasive grains held by the grinding means into sliding contact with the polishing cloth, the distance from the center of the rotary platen. Are different from each other, and
A feature is that the cross-sectional shape of the polishing cloth is controlled to a desired shape by using a plurality of grinding means arranged so that the locus drawn on the rotary platen during the grinding operation covers the radius of the rotary platen. And polishing method. 6. The polishing method according to claim 5, wherein at least one of the number of revolutions of each of the grinding means, the pressing pressure against the polishing cloth, and the pressing angle is controlled independently of the other grinding means. . 7. The polishing method according to claim 6, wherein each of the grinding means is swung in the radial direction of the rotary platen. 8. The polishing method according to claim 5, wherein the polishing agent is supplied to one or more locations near the grinding means.