JP3360488B2 - Polishing apparatus and polishing 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 polishing apparatus for performing chemical mechanical polishing, and more particularly to a polishing apparatus capable of simultaneously processing a plurality of substrates having steps in a manufacturing process of a semiconductor device or the like. The present invention also relates to a polishing method using the polishing device.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor devices, the capacity of devices has been increased, and multilayer wiring technology has become important in order to reduce the chip area as much as possible to increase the capacity. In this multi-layer wiring technology, it is necessary to flatten the base. This is because if there is unevenness in the base, a step is generated due to this, and the wiring formed on the step is cut, which causes a problem such as so-called step disconnection.

In order to flatten a wafer, a method of removing a convex portion of a step by chemical mechanical polishing (hereinafter referred to as CMP) has been applied.

In order to perform the CMP, for example, a polishing apparatus as shown in a sectional view of FIG. 13 is used. This polishing apparatus mainly includes a rotating platen 10 on which a polishing cloth 101 is stretched.
2. It comprises abrasive supply means 112 for supplying the abrasive 103 onto the polishing cloth 101, and a substrate holder 106 for holding the wafer (substrate) 104 in close contact.

The rotary platen 102 is connected to a motor (not shown) via a shaft 102s provided at the center of the rotary platen 102, so that the rotary platen 102 is rotatable in the direction of arrow A.

The base holder 106 is connected to a drive mechanism (not shown) through a shaft 106s provided at the center of the base holder 106, so that the base holder 106 can be rotated in the direction of arrow B and can be rotated in the direction of arrow C. Is also movable, and the substrate 1
04 can be brought into sliding contact with / separating from the polishing cloth 101.

To actually perform polishing by the above-described polishing apparatus, first, the substrate 104 is rotated while the substrate 104 is held on the substrate holder 106. Also, the abrasive 103 is supplied onto the polishing cloth 101 from the abrasive supply means 112 while rotating the rotary platen 102. Then, the base 104 is polished by bringing the polished surface of the base 104 into sliding contact with the polishing cloth 101 via the abrasive 103. At this time, the base 104 is revolved by the rotation of the rotary platen 102 while rotating by the rotation of the base holding table 106, so that one point on the polished surface of the base 104 is
The trajectory drawn on 01 is the revolution path, and highly uniform polishing can be performed.

In such a polishing apparatus, the polishing cloth 10
The surface roughness 1 greatly affects the polishing characteristics such as the polishing rate and the achievable flatness. For this reason, the polishing cloth 101
Usually, a flexible material such as polyurethane is used after being adjusted to a desired surface roughness. However, since the polishing cloth 101 is worn during polishing and the surface roughness changes, it is necessary to grind the polishing cloth 101 in order to prevent the polishing characteristics from changing over time.
Therefore, in the above-described polishing apparatus, a grinding head 110 in which grinding grains 108 such as diamond are embedded is provided, and the grinding is performed by bringing the grinding grains 108 into sliding contact with the polishing cloth 101. . The grinding head 110 is connected to a drive mechanism (not shown) via a shaft portion 110s provided at the center thereof, so that the grinding head 110 can be rotated in a direction indicated by an arrow D at a desired number of rotations, and can be rotated in a direction indicated by an arrow E Is also movable, so that the sliding contact / separation with the polishing cloth 101 can be controlled.

The grinding using such a grinding head 110 may be performed after a predetermined amount of polishing is completed. However, in order to suppress a change in polishing characteristics during polishing, the grinding is performed simultaneously with the polishing. (Hereinafter referred to as simultaneous grinding),
It is preferable that the surface roughness of the polishing pad 101 is always kept constant.

[0010]

By the way, in the polishing step using the polishing apparatus as described above, in order to improve the throughput, a plurality of substrate holders 106 are arranged on a single rotary platen 102. It is effective that the plurality of substrates 104 are polished at the same time.

For this purpose, for example, as shown in FIG.
A polishing apparatus that can simultaneously polish the two substrates 104 and 105 may be used.

However, in such a polishing apparatus, even if the grinding head 110 is provided and simultaneous grinding is performed, the polishing rate of the substrates 104 and 105 held between the two substrate holding tables 106 and 107 can be controlled. Polishing characteristics such as achievable flatness are different.

This is because the polishing cloth 101 immediately after being ground by the grinding head 110 has a desired surface roughness, so that the base 104 can be appropriately polished. Polishing cloth 10 on the downstream side in the rotation direction
This is because the polishing pad 101 whose surface roughness has deteriorated due to the sliding contact with the substrate 104 is polished on the substrate 105 sliding on the substrate 105.

[0014] As the number of substrates to be polished at the same time increases, the variation in polishing characteristics among the substrates increases. For this reason, it has been difficult to achieve both improved throughput and uniform polishing characteristics.

Accordingly, the present invention has been proposed in view of such a conventional situation, and when polishing a plurality of substrates on one rotating platen, uniform polishing characteristics are applied to all the substrates. An object of the present invention is to provide a polishing apparatus capable of performing polishing by using a polishing apparatus. Another object of the present invention is to provide a polishing method using such a polishing apparatus.

[0016]

SUMMARY OF THE INVENTION A polishing apparatus according to the present invention has been proposed to achieve the above-mentioned object, and comprises a single rotating platen on which a polishing cloth is stretched, and the polishing cloth. An abrasive supply means for supplying an abrasive onto the substrate, a plurality of substrate holders for holding the substrate in close contact with the substrate, and slidingly contacting the substrate with the polishing cloth, and at least one or more for each substrate holder Grinding means for adjusting the surface roughness of the polishing cloth by bringing the abrasive grains held by the polishing pad into sliding contact with the polishing cloth. Each of them is arranged so as to be independently rotatable on the upstream side in the rotation direction of the rotary platen.

That is, since the grinding means is provided for each of the plurality of substrate holders, the surface roughness of the substrates held on any of the substrate holders is the same by the grinding means. This is to bring the adjusted polishing cloth into sliding contact. For this purpose, it is necessary to re-adjust the surface roughness of the area of the polishing cloth by the grinding means after sliding on a certain substrate and before sliding on the next substrate.

Therefore, each of the grinding means is preferably a grinding head which is independently rotatably arranged on the upstream side in the rotation direction of the rotary platen with respect to each of the base holders. In order to appropriately control the surface roughness of the polishing cloth, it is preferable that the number of rotations of each grinding head and the pressure applied to the polishing cloth can be adjusted. In order to make a large number of substrate holders face each other within a limited area of the rotary platen, it is preferable that the area occupied by each grinding head is small. Therefore, even if the diameter is small, a wide area of the polishing cloth can be ground. In addition, it is preferable that each of the grinding heads can swing in the radial direction of the rotary platen.

Further, each of the grinding means may be provided concentrically on the outer edge of each of the substrate holders, and may be configured to rotate integrally with each of the substrate holders. For example, a ring-shaped grinding head that surrounds the periphery of each of the disk-shaped substrate holders may be used. In this grinding head, the abrasive grains may be embedded over the entire surface, or the abrasive grains may be radially divided into a plurality of regions and embedded. In such a grinding means, the number of revolutions depends on the number of revolutions of the substrate holder, and the pressure applied to the polishing pad also depends on the pressure of the substrate holder. However, if the relative position of the grinding head to the substrate holder can be adjusted, the pressing pressure of the grinding head can be controlled independently.

Further, a plurality of grinding means may be provided at the outer edge of each substrate holder, and each may be rotatable.
For example, a disk-shaped grinding head having a smaller diameter than the substrate holding table may be used. In such a grinding means, the number of revolutions of revolution follows the number of revolutions of the base holder. However, it is preferable that the number of revolutions of revolution and the pressure applied to the polishing pad can be adjusted.

In addition, as described above, at the outer edge of the base holder, a grinding means that rotates integrally with the base holder, or a grinding means that revolves around the base holder. Can be applied to a polishing apparatus having only one base holder. However, it is more effective when applied to polishing a plurality of substrates simultaneously. This is because the grinding means provided on the outer edge of the substrate holding table grinds the polishing cloth in the area that comes into sliding contact with the substrate in two stages immediately before and after sliding with the substrate. That is, by providing two or more sets of the substrate holding table and the grinding means for the outer edge portion, grinding performed immediately after sliding contact with the substrate by the grinding means around the upstream substrate and the periphery of the downstream substrate Thus, the polishing cloth can be efficiently adjusted to a predetermined surface roughness by combining with the grinding performed immediately before sliding contact with the substrate by the grinding means. Further, when the grinding means is provided on the outer edge of the base holder as described above, it is advantageous to make many base holders face each other within a limited area of the rotary platen.

In controlling the surface roughness of the polishing pad, it is important to select the hardness and particle size of the abrasive grains. This material is at least one selected from diamond, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), boron nitride (BN), titanium nitride (TiN), silicon oxide (SiO ₂ ), and cerium oxide (CeO). Seeds are preferred.

Further, in order to polish a plurality of substrates with uniform polishing characteristics, in addition to polishing so that the surface roughness of the polishing cloth to be brought into sliding contact is substantially equal, a polishing agent may be used. It is also necessary that they are supplied under substantially equal conditions. For this reason, it is preferable that at least one abrasive supply means is provided for each substrate holder.

In the polishing method according to the present invention, the substrate is polished by using the above-described polishing apparatus.
That is, while the abrasive is supplied onto the polishing cloth stretched on a single rotary platen, the surfaces to be polished of the plurality of substrates respectively held on the plurality of substrate holding tables are brought into sliding contact with the polishing cloth. Accordingly, when the plurality of substrates are simultaneously polished, at the same time as the polishing, a polishing pad is provided with at least one polishing pad for each of the substrate holders so that the surface roughness of the polishing pad is substantially equal in a region where the substrate is in sliding contact with any of the substrates. And at least one of the base holders is ground by an independently rotating grinding means on the upstream side in the rotation direction of the rotary platen.

Here, in order to grind the surface roughness of the polishing cloth so as to be substantially equal in the area where the polishing cloth slides on any of the substrates, a grinding means having the above-described structure may be used.
At least one abrasive supply means may be provided for each substrate holder.

[0026]

According to the present invention, if one or more grinding means are provided for each substrate holder, a polishing cloth having substantially the same surface roughness can be slid on the substrate held on any substrate holder. It is possible to make contact.

In the case where each of the grinding means is a grinding head which is arranged so as to be independently rotatable on the upstream side in the rotation direction of the rotary platen with respect to each of the substrate holders, a plurality of substrates are provided. Even if polishing is performed at the same time, since the surface roughness of the polishing cloth can be readjusted on the upstream side of each substrate, a polishing cloth having substantially the same surface roughness can be brought into sliding contact with any of the substrates. it can.

If the grinding head can be swung in the radial direction of the rotary platen, the diameter can be reduced, so that many substrate holders can be opposed to each other within a limited area of the rotary platen. It becomes possible.

In the case where each of the grinding means is disposed concentrically on the outer edge of each of the substrate holders and is disposed so as to rotate integrally with each of the substrate holders, or Even when a plurality of base holders are provided on the outer edge of the base holder and each can rotate, it is easy to make many base holders face each other within a limited area of the rotary platen. Further, two-stage grinding is performed until a certain area of the polishing cloth comes into sliding contact with the substrate, namely, grinding immediately after sliding with the upstream substrate and grinding immediately before sliding with the downstream substrate. Therefore, the grinding of the polishing pad and the polishing of the base can be performed efficiently by providing two or more sets of the base support and the accompanying grinding means.

When the grinding means is arranged so as to rotate integrally with each substrate holder, no new driving mechanism is required to operate the grinding means, and the grinding means has a simple structure. Sufficient grinding can be performed.

In the case where a plurality of grinding means are provided at the outer edge of each substrate holder and each of them is rotatable, the grinding means is more effective for polishing the polishing cloth than when it is operated only by rotating the substrate holder. The relative sliding speed can be increased, and more uniform grinding can be performed.

Therefore, when a plurality of substrates are simultaneously polished using the above-described polishing apparatus, the polishing characteristics between the substrates can be made uniform while improving the throughput.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a polishing apparatus according to the present invention and a polishing method used therein will be described with reference to specific examples.

Embodiment 1 In the polishing apparatus of this embodiment, two grinding units are provided so as to be independently rotatable with respect to two substrate holders on the upstream side in the rotation direction of the rotary platen. Means. Hereinafter, the polishing apparatus will be described with reference to a plan view shown in FIG. 1, a cross-sectional view taken along line aa 'of FIG. 1, and a cross-sectional view taken along line bb' of FIG. 1 shown in FIG. I will explain while.

This polishing apparatus has an average roughness Ra of 0.5 μm.
a rotating platen 2 on which an abrasive cloth 1 of m is stretched; abrasive supply means 12 for supplying an abrasive 3 in a slurry state onto the polishing cloth 1;
A first substrate holder 6 and a second substrate holder 7 for holding the substrate 13 and the substrates 4 and 5 in close contact with each other, and bringing the substrates into sliding contact with the polishing pad 1; The first grinding head 10 and the second grinding head 11 are each independently rotatably arranged at a predetermined point on the side.

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

The first base holder 6 and the second
The base holding table 7 also has shaft portions 6s, 7 provided at the center thereof.
By being connected to a drive mechanism (not shown) via s, the bases 4 and 5 can be rotated in the direction of arrow B and can also be moved in the direction of arrow C, so that sliding contact / separation with the polishing cloth 1 is possible. It has been made controllable.

The first grinding head 10 and the second grinding head 11 are respectively buried with grinding abrasive grains 8 and 9 made of diamond having a particle diameter of 100 μm, and are brought into sliding contact with the polishing cloth 1 while rotating them. A predetermined surface roughness is generated on the downstream side. In addition,
These first grinding head 10 and second grinding head 1
1 is connected to a drive mechanism (not shown) via shafts 10s and 11s provided at the center thereof, thereby being able to rotate in the direction of arrow D at a desired number of rotations.
It is also movable in the direction of arrow E, so that the sliding contact / separation of the abrasive grains 8, 9 against the polishing cloth 1 and the pressing pressure can be controlled. The first grinding head 10 and the second grinding head 11 can swing in the radial direction of the rotary platen 2 (the direction of arrow F).

When such a polishing apparatus is used, the polishing cloth 1
Then, the abrasive grains 8 and 9 of the first grinding head 10 and the second grinding head 11 are brought into sliding contact with each other to generate a predetermined surface roughness on the downstream side thereof. Polishing can be performed by bringing the polished surfaces of the substrates 4 and 5 held by the first base holder 6 and the second base holder 7 into sliding contact with the polishing cloth 1.

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

First, as shown in FIG. 4, a lower insulating film 52 made of silicon oxide and an Al
Pattern 53 made of a base material, said wiring pattern 53
A wafer was prepared in which an interlayer insulating film 54 covering the layers was formed in order. Here, the interlayer insulating film 54 is formed under the following film forming conditions.

Film formation conditions for 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 base having the above-described structure was polished as described below, thereby removing the projecting portions of the steps of the interlayer insulating film 54 and flattening.

More specifically, first, the two wafers (substrates 4 and 5) described above are firstly held on the first substrate holder 6 and the second substrate holder so that the interlayer insulating film 54 faces the polishing pad 1, respectively. The rotating platen 2 was rotated at 17 rpm while being held on the table 7 and rotated at 17 rpm.
A slurry-like abrasive 3 composed of potassium hydroxide / water was supplied. The polishing cloth 1 has a first grinding head 1.
The holding surfaces of the abrasive grains 8, 9 in the 0, second grinding head 11 were brought into sliding contact with a pressing pressure of 30 kgf while rotating at 50 rpm. Then, the bases 4 and 5 were brought into sliding contact with the polishing pad 1 on which the first and second grinding heads 10 and 11 had been ground.

By such simultaneous grinding, polishing is performed on each of the bases 4 and 5 in a state where the average roughness of the polishing pad 1 is made equal, and as shown in FIG. , 5 are flattened.

Thereafter, the substrates 4 and 5 are separated from the polishing cloth 1, the substrates 4 and 5 are washed with a hydrogen fluoride (HF) aqueous solution, and the polishing agent 3 adhered to the polished surfaces of the substrates 4 and 5. Was removed.

As shown in FIG. 6, the surface roughness of the polishing cloth at a certain point x is reduced from R ₁ to R ₂ by sliding contact with the substrate 4 or the substrate 5, and the abrasive grains 8 or The change of R ₂ to R ₁ by sliding contact with the abrasive grains 9 is repeated. Here, R ₁ has an average roughness Ra = 0.5 μm, and R ₂ has an average roughness Ra = 0.3 μm.

Therefore, when the polishing is performed as in this embodiment, even if the base 4 and the base 5 are simultaneously polished, a polishing cloth having substantially the same surface roughness can be brought into sliding contact with both the base 4 and the base 5. it can. For this reason, it was possible to achieve both improvement in throughput and uniform polishing characteristics without variation in polishing characteristics between the substrates 4 and 5.

Embodiment 3 The polishing apparatus of this embodiment is provided with a grinding means which is disposed concentrically on each outer edge of two substrate holders and rotates integrally with each of the substrate holders. . Hereinafter, the polishing apparatus will be described with reference to a plan view shown in FIG.
Description will be made with reference to a cross-sectional view taken along line -a '. Members having the same configuration as the polishing apparatus shown in the first embodiment are denoted by the same reference numerals, and the common description is omitted.

In this polishing apparatus, a rotating platen 2 on which a polishing cloth 1 is stretched, and an abrasive 3 in a slurry state
Abrasive supply means 12 and 13 for supplying the liquid and the substrates 4 and 5 are held in close contact with each other, and the first
The first and second substrate holders 6 and 7 correspond to the first embodiment.
It has the same configuration as that of the polishing apparatus of (1). Then, in the polishing apparatus of the present embodiment, instead of providing the first grinding head 10 and the second grinding head 11 that can be independently rotated, the outer edge of the first base holder 6 is A first grinding head 20 that rotates integrally with the first substrate holder 6 is provided, and rotates at the outer edge of the second substrate holder 7 integrally with the second substrate holder 7. A second grinding head 21 is provided.

The first grinding head 20 and the second grinding head 21 are formed in a ring shape so as to surround the outer edges of the first base holder 6 and the second base holder 7, respectively. Grinding abrasive grains 18 and 19 made of diamond having a particle diameter of 80 μm are embedded in the surface facing the cloth 1. Note that, as shown in FIG. 9, the bottom surface of the first grinding head 20, the abrasive grains 18 are embedded in a plurality of regions radially divided into a plurality of regions.
Similarly, on the bottom surface, the abrasive grains 19 are radially divided and embedded in a plurality of regions.

The first grinding head 20 and the second grinding head 21 rotate in the direction of arrow B in accordance with the rotation of the first base holder 6 and the second base holder 7, and the base holders 6 and 21 rotate. , 7 can also be moved in the direction of arrow C. However, both grinding heads 20, 2
Reference numeral 1 indicates that the relative position of each of the base holders 6 and 7 can be adjusted, and the polishing cloth 1 can be ground at a desired pressing pressure.

Using such a polishing apparatus, the polishing cloth 1
While the abrasive grains 18 and 19 of the first and second grinding heads 20 and 21 are slid in contact with each other, the first and second substrate holders 6 and 7 on the inner peripheral side thereof are brought into contact with each other.
When the surfaces to be polished of the substrates 4 and 5 held by the polishing pad 1 are brought into sliding contact with each other, the area of the polishing pad 1 is brought into contact with the substrate 4 by the second grinding head 21 immediately after the sliding contact with the substrate 5. , And grinding by the first grinding head 20 immediately before sliding contact with the base 4 is performed in two stages. Similarly, a certain area of the polishing cloth 1 is ground by the first grinding head 20 immediately after the sliding contact with the substrate 4 and by the second grinding head 21 immediately before the sliding contact with the substrate 5 before sliding on the substrate 5. , A two-stage grinding is performed.

For this reason, in the polishing apparatus of the present embodiment, the substrates 4 and 5 can be polished while the polishing cloth 1 is efficiently ground. Further, in this polishing apparatus, a new driving mechanism is not required for operating the grinding heads 20 and 21, and sufficient grinding can be performed with a simple configuration.

Embodiment 4 Hereinafter, an example in which the step of forming an interlayer flattening film in the semiconductor device manufacturing process is performed using the polishing apparatus of Embodiment 3 as described above will be described.

Specifically, first, as in the second embodiment, a lower insulating film 5 made of silicon oxide is formed on a silicon substrate 51.
2. Two wafers (substrates 4 and 5) in which a wiring pattern 53 made of an Al-based material and an interlayer insulating film 54 covering the wiring pattern 53 are sequentially formed, and the interlayer insulating film 54 is The first substrate holder 6 and the second substrate holder 7 were held so as to face each other.

The rotating platen 2 is rotated at 17 rpm to supply the abrasive 3 onto the polishing pad 1, while the first substrate holder 6 and the second substrate holder 7 are each rotated at 17 rpm. By doing so, the first base holder 6 and the first base holder 7 provided at the outer edge of the second base holder 7 are respectively provided.
The grinding head 20 and the second grinding head 21 were also rotated.

Then, the bases 4 and 5 held on the first base holder 6 and the second base holder 7 and the abrasive grains embedded in the first grinding head 20 and the second grinding head 21, respectively. 18 and 19 were brought into sliding contact with the polishing cloth 1. here,
The pressing pressure of the grinding heads 20 and 21 against the polishing pad 1 was adjusted according to the relative positions of the base holders 6 and 7 to 30 kgf.

By such simultaneous grinding, polishing was performed on both of the substrates 4 and 5 in a state where the average roughness Ra of the polishing cloth 1 was equalized, and the interlayer insulating film 54 was flattened. Thereafter, the substrates 4 and 5 were separated from the polishing pad 1, and the polishing agent 3 attached to the polished surfaces of the substrates 4 and 5 was removed in the same manner as in Example 2.

As shown in FIG. 10, the point y of the polishing cloth 1 is brought into sliding contact with the abrasive grains 18 on the outer peripheral side thereof immediately before the sliding contact with the substrate 4, so that the surface roughness becomes r. It was allowed to recover to r ₁ from _2, sliding contact with the base body 4. Then, by the sliding contact with the base body 4, the surface roughness from r ₁ r
_{Even if} it drops to ₃ , immediately after that,
The surface roughness is restored from r ₃ to r ₂ by sliding on. Similarly, the surface roughness that maintained r ₂ is
Immediately before the sliding contact with the base member 5, the sliding member comes into sliding contact with the abrasive grains 19 on the outer peripheral side thereof, thereby recovering to r ₁ . Immediately after that, even if the temperature decreases from r ₁ to r ₃ due to the sliding contact with the base member 5, immediately after that, it is restored from r ₃ to r ₂ again by the sliding contact with the abrasive grains 19. As described above, the polishing cloth 1 is repeatedly ground immediately before and after sliding on the bases 4 and 5 by the abrasive grains 18 and 19 provided on the outer peripheral side of the bases 4 and 5. Here, r ₁ is the average roughness Ra = 0.4 μm, and r ₂ is the average roughness Ra = 0.37.
μm and r ₃ are average roughness Ra = 0.3 μm.

Therefore, when the polishing is performed as in this embodiment, even if the substrate 4 and the substrate 5 are simultaneously polished, a polishing cloth having substantially the same surface roughness can be brought into sliding contact with both. it can. Therefore, it was possible to achieve both improvement in throughput and uniform polishing characteristics without variation in polishing characteristics between the substrates 4 and 5.

Embodiment 5 In the polishing apparatus of this embodiment, a plurality of grinding means are provided at each outer edge of two base holders, and the grinding means themselves rotate. Hereinafter, the polishing apparatus will be described with reference to the plan view of FIG. Members having the same configurations as those of the polishing apparatuses shown in the first and third embodiments are denoted by the same reference numerals, and the common description is omitted.

In this polishing apparatus, a rotating platen 2 on which a polishing cloth 1 is stretched, and a slurry-like polishing agent 3 on the polishing cloth 1
Abrasive supply means 12 and 13 for supplying the liquid and the substrates 4 and 5 are held in close contact with each other, and the first
The first and second substrate holders 6 and 7 correspond to the first embodiment.
It has the same configuration as that of the polishing apparatus of (1). On the outer edge of the first base holder 6, eight first disc-shaped first orbits that revolve with the rotation of the first base holder 6 and rotate themselves.
A grinding head 30 is provided. Similarly, the outer edge of the second base holder 7 revolves along with the rotation of the second base holder 7, and the disk head 8 also rotates itself. A second grinding head 31 is provided.

The first grinding head 30 and the second grinding head 31 each have a smaller diameter than the base holders 6 and 7, and as shown in a sectional view of FIG. Grinding abrasive grains 28 and 29 made of diamond having a particle diameter of 100 μm are embedded respectively. The respective centers are connected to a motor (not shown) via the shaft portions 30s and 31s, so that they can rotate in the direction of arrow G. In addition, the motor has eight first grinding heads 3.
It is not necessary to be connected one by one to each of the 0, 8 second grinding heads 31. Here, the eight first grinding heads 30 are rotated by one motor, and the eight second grinding heads 30 are rotated. Was rotated by another motor.

Therefore, these first grinding heads 30
The second grinding head 31 revolves in the direction of arrow B in accordance with the rotation of the first base holder 6 and the second base holder 7, and revolves to rotate the abrasive grains 28 and 29. Make a revolution. The sliding contact / separation of the first grinding head 30 and the second grinding head 31 with respect to the polishing cloth 1 is performed with the movement of the first base holder 6 and the second base holder 7. Each grinding head 3
The pressing pressures of 0 and 31 on the polishing cloth 1 are each adjustable.

Using such a polishing apparatus, the polishing cloth 1
While the abrasive grains 28 and 29 of the first and second grinding heads 30 and 31 are slid in contact with each other, the first and second substrate holders 6 and 7 on the inner peripheral side of these are fixed.
When the surfaces to be polished of the substrates 4 and 5 held in contact with each other are brought into sliding contact with each other, as in the case of using the polishing apparatus of the third embodiment, a certain area of the polishing cloth 1 Immediately after the sliding contact, the first grinding head 30 and the second grinding head 31 perform two-stage grinding, and then come into sliding contact with the substrates 4 and 5.

Therefore, in the polishing apparatus of this embodiment, the substrates 4 and 5 can be polished while efficiently polishing the polishing pad 1. Also, in this polishing apparatus, eight first grinding heads 30 and second grinding heads 31 are provided, each of which is arranged to rotate on its own. Abrasive grains 2 for
The relative sliding speed of 8, 29 can be increased, and more uniform grinding can be performed.

Embodiment 6 Hereinafter, an example in which a step of forming an interlayer flattening film in a semiconductor device manufacturing process is performed using the polishing apparatus of Embodiment 5 as described above will be described.

Specifically, first, as in the second embodiment, a lower insulating film 5 made of silicon oxide is formed on a silicon substrate 51.
2. Two wafers (substrates 4 and 5) in which a wiring pattern 53 made of an Al-based material and an interlayer insulating film 54 covering the wiring pattern 53 are sequentially formed, and the interlayer insulating film 54 is The first substrate holder 6 and the second substrate holder 7 were held so as to face each other.

The rotating platen 2 is rotated at 17 rpm to supply the abrasive 3 onto the polishing pad 1, while the first substrate holder 6 and the second substrate holder 7 are each rotated at 17 rpm.
By rotating at m, the first grinding head 30 and the second grinding head 31 provided at the outer edges of the base holders 6 and 7 revolved, respectively. At the same time, each of the grinding heads 30, 31 was rotated.

The bases 4 and 5 held on the first base holder 6 and the second base holder 7 and the abrasive grains embedded in the first grinding head 30 and the second grinding head 31, respectively. 28 and 29 were brought into sliding contact with the polishing pad 1. here,
The pressing pressure of each of the grinding heads 30, 31 against the polishing pad 1 was 30 kgf.

By such simultaneous grinding, polishing was performed on both the substrates 4 and 5 in a state where the average roughness of the polishing cloth 1 was equalized, and the interlayer insulating film 54 was flattened. Thereafter, the substrates 4 and 5 were separated from the polishing pad 1, and the polishing agent 3 attached to the polished surfaces of the substrates 4 and 5 was removed in the same manner as in Example 2.

Incidentally, a certain point z of the polishing cloth 1 is the same as in the fourth embodiment, except that the abrasive grains 2 provided on the outer peripheral side of the substrates 4 and 5
According to Nos. 8 and 29, grinding was performed immediately before and immediately after sliding on the substrates 4 and 5 to recover the surface roughness in two stages, and then sliding on the substrates 4 and 5 was repeated.

Therefore, when the polishing is performed as in the present embodiment, even if the base 4 and the base 5 are simultaneously polished, a polishing cloth having substantially the same surface roughness can be brought into sliding contact with both. it can. Therefore, it was possible to achieve both improvement in throughput and uniform polishing characteristics without variation in polishing characteristics between the substrates 4 and 5.

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 embodiment, and various modifications can be made. For example, in the polishing apparatus of the first embodiment, the first
The grinding head 10 and the second grinding head 11 are made smaller in diameter than the bases 4 and 5 and are swung in the radial direction of the rotary platen 2. If the rotary platen 2 has a sufficient area, Alternatively, the swinging may not be performed by setting the diameters of the two grinding heads 10 and 11 to be equal to or larger than those of the bases 4 and 5.

In the polishing apparatus according to the third embodiment, the areas where the abrasive grains 18 and 19 are embedded and the areas where the abrasive grains 18 and 19 are not embedded are provided on the surfaces of the first grinding head 20 and the second grinding head 21 facing the polishing cloth 1. However, the abrasive grains 18 and 19 may be embedded over the entire surface.

Further, in the polishing apparatus of the fifth embodiment,
Eight grinding heads 3 for each base holder 6, 7
Although 0 and 31 are provided, the number is not limited to this.
Further, one motor may be provided for each of the grinding heads 30 and 31.

In addition, various modifications can be made without departing from the spirit of the present invention, such as by increasing the number of substrate holders and grinding heads so that three or more substrates can be polished at once. is there.

The present invention can be applied not only to the flattening of an interlayer insulating film but also to the formation of a flattened element isolation region, the inside of a trench of a buried insulating film formed on a semiconductor substrate having a trench. It may be applied to remove parts other than. Also, the present invention relates to a bonded SOI (silicon
It can also be applied to the formation of a silicon active layer using an (insulator) substrate.

[0080]

As is apparent from the above description, by applying the present invention, a polishing apparatus provided with one or more grinding means for each substrate holder can be used for any substrate holder. On the other hand, it is possible to bring a polishing cloth having a substantially equal surface roughness into sliding contact.

Therefore, using such a polishing apparatus,
When a plurality of substrates are polished at the same time, the polishing characteristics between the substrates can be made uniform while improving the throughput.

Therefore, when the present invention is applied to, for example, flattening in a manufacturing process of a semiconductor device, it is possible to manufacture a device having a multilayer wiring structure having a high reliability with an excellent throughput.

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view showing a section taken along line aa ′ in FIG. 1;

FIG. 3 is a schematic sectional view showing a section taken along line bb ′ in FIG. 1;

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

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

FIG. 6 is a time chart showing a change in surface roughness at a certain point x of the polishing pad in polishing using an example of the polishing method according to the present invention.

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

FIG. 8 is a schematic sectional view showing a section taken along line aa ′ in FIG. 7;

FIG. 9 is a schematic bottom view showing the grinding head in FIG. 7;

FIG. 10 is a time chart showing a change in surface roughness at a certain point x of a polishing pad in polishing using another example of the polishing method according to the present invention.

FIG. 11 is a schematic plan view showing still another configuration example of the polishing apparatus according to the present invention.

FIG. 12 is a schematic sectional view showing the grinding head in FIG. 11;

FIG. 13 is a schematic cross-sectional view showing one configuration example of a conventional polishing apparatus.

FIG. 14 is a schematic plan view showing another configuration example of a conventional polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing cloth 2 Rotating surface plate 3 Abrasive 4,5 Substrate 6 First substrate holder 7 Second substrate holder 8,9 Grinding abrasive grain 10 First grinding head 11 Second grinding head 12,13 Polishing Agent supply pipe 51 Silicon substrate 52 Lower insulating film 53 Wiring pattern 54 Interlayer insulating film

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI H01L 21/304 H01L 21/304 622R B24B 37/00 B24B 37/00 A (58) Fields investigated (Int. Cl. ⁷ , DB Name) H01L 21/304 621 H01L 21/304 622 B24B 37/00

Claims (10)

(57) [Claims] 1. A single rotating platen on which a polishing cloth is stretched, an abrasive supply means for supplying an abrasive onto the polishing cloth, and a substrate held in close contact with the polishing pad while rotating the substrate. A plurality of substrate holders for sliding contact with, at least one or more provided for each substrate holder,
Grinding means for adjusting the surface roughness of the polishing cloth by bringing the abrasive grains held by itself into sliding contact with the polishing cloth; and the grinding means comprises: A polishing apparatus, wherein each of the polishing apparatuses is arranged so as to be independently rotatable on an upstream side in a rotation direction of the board. 2. The polishing apparatus according to claim 1, wherein said grinding means is swingable in a radial direction of said rotary platen. 3. The apparatus according to claim 1, wherein each of the grinding means is concentrically disposed on an outer edge portion of each of the substrate holders, and is rotatable integrally with each of the substrate holders. The polishing apparatus according to the above. 4. The polishing apparatus according to claim 1, wherein a plurality of said grinding means are provided at an outer edge portion of each base holder, and each of said grinding means is capable of rotating. 5. The method according to claim 1, wherein the abrasive grains are diamond, silicon carbide, aluminum oxide, boron nitride, titanium nitride,
At least one selected from silicon oxide and cerium oxide
The polishing apparatus according to claim 1, wherein the polishing apparatus is made of a seed. 6. The polishing apparatus according to claim 1, wherein at least one abrasive supply means is provided for each of said substrate holders. 7. A polishing cloth is stretched on a single rotating platen, and a polishing agent is supplied onto the polishing cloth. When the plurality of substrates are polished at the same time by being brought into sliding contact with each other, the polishing cloth is held at the same time as the polishing so that the surface roughness of each of the substrates is substantially equal in a region where any of the substrates comes into sliding contact with each other. A polishing method, characterized in that at least one or more is provided for each base, and each of the base holders is ground by an independently rotating grinding means on the upstream side in the rotation direction of the rotary platen. 8. The polishing method according to claim 7, wherein said grinding means is swung in a radial direction of said rotary platen. 9. The polishing method according to claim 7, wherein at least one kind of abrasive grains selected from diamond, silicon carbide, aluminum oxide, boron nitride, titanium nitride, silicon oxide, and cerium oxide is used. 10. A method according to claim 1, wherein at least one
The polishing method according to claim 7, wherein the polishing agent is supplied onto the polishing cloth by at least one polishing agent supply means.