JP2003200348A - Polishing method for wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CMP device that can uniformize a polishing amount of each of simultaneously polished wafers and can appropriately supply abrasive slurry to the wafers even when the supplied abrasive slurry has a high flow rate. <P>SOLUTION: The CMP device comprises a surface plate 10 driven for rotation about a first rotation axis Ax1, an abrasive pad 11 stuck on the surface plate 10, two sets of carriers 20 driven for rotation about second rotation axes Ax2 eccentric to the first rotation axis Ax1 and designed to hold wafers 12 and press them against the abrasive pad 11 respectively, a supply nozzle 30 for supplying abrasive slurry 13 onto the abrasive pad 11, and a regulation mechanism 40 for regulating a tip position of the supply nozzle 30 relative to the abrasive pad 11. The tip of the supply nozzle 30 is moved appropriately in dependence on the supply of the abrasive slurry, the positions of the wafers, and the like to regulate the supply position of the abrasive slurry. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method in a manufacturing process of a semiconductor device and a polishing apparatus used in this method, and more particularly, to chemical mechanical polishing (Chemica).
l Mechanical Polish (CMP) device.

[0002]

15 and 16 show a state of polishing using a conventional CMP apparatus. FIG. 15 is a side view and FIG. 16 is a plan view. The main part of the CMP apparatus is two sets of carriers 2a, which hold and rotate the wafers 1a and 1b, respectively.
2b and a rotatable surface plate 4 having a polishing pad 3 fixed to the upper surface thereof. The carriers 2a and 2b rotate while pressing the wafers 1a and 1b against the polishing pad 3. In addition, the CMP apparatus includes an abrasive on the polishing pad 3.
A supply nozzle 6 for supplying (slurry) 5 is provided.

During polishing, pressure is applied while rotating the carriers 2a and 2b to press the wafers 1a and 1b against the polishing pad 3 and rotate the surface plate 4. At the same time, the polishing slurry 5 is supplied onto the polishing pad 3 from the supply nozzle 6.
As a result, the surfaces of the wafers 1a and 1b are polished by the polishing pad 3
And the polishing slurry 5 are used to chemically and mechanically polish and planarize.

[0004]

However, in the above-mentioned conventional CMP apparatus, since the supply nozzle 6 is fixedly provided at one location, the polishing slurry 5 does not spread evenly on the polishing pad 3, and However, there is a problem in that the polishing amount is uneven. For example, when the surface plate 4 rotates counterclockwise as shown in FIG. 16, the carrier 2a located upstream in the rotation direction with respect to the supply position of the polishing slurry 5 is more than the other carrier 2b side. Wafer 1a, which is supplied with the polishing slurry 5 and held by the carrier 2a
1 whose polishing amount is held by the other carrier 2b
It becomes larger than the polishing amount of b.

The amount of polishing slurry supplied per hour
(Flow rate) depends on the process of the wafer to be polished,
When the flow rate is relatively large, the flow velocity of the polishing slurry discharged from the supply nozzle 6 increases, and the polishing slurry bounces on the polishing pad 3 and is not supplied to the wafer, but jumps out of the polishing pad 3. There's a problem.

The present invention has been made in view of the above-mentioned problems of the prior art. When polishing a plurality of wafers at the same time, the polishing amount between the wafers can be made uniform, and the wafers can be supplied. It is an object to provide a CMP apparatus that can appropriately supply the polishing slurry to the wafer even when the flow rate of the polishing slurry is large.
And

[0007]

Therefore, the present invention has been made in view of the above matters, that is, the present invention is based on the first aspect.
The wafer is pressed against a polishing pad attached on a surface plate that is rotationally driven about the rotation axis of the carrier by a carrier that is rotationally driven about a second rotation axis that is eccentric from the first rotation axis. The method is characterized by including a step of driving the disk and the carrier to polish the wafer, and a step of supplying a polishing slurry onto the polishing pad while moving a nozzle.

Further, the tip of the nozzle according to the present invention may have a shape bent downward.

Further, a plurality of supply holes may be formed at the tip of the nozzle in the present invention.

Further, according to the present invention, a polishing pad attached on a surface plate which is rotationally driven about a first rotation axis is rotated about a second rotation axis eccentric from the first rotation axis. The wafer is pressed by the driven carrier, the step of polishing the wafer by driving the surface plate and the carrier, and supplying the polishing slurry to the slurry pool provided in the rotating shaft part, and from the slurry pool. And a step of discharging polishing slurry to a polishing pad.

In addition, the slurry reservoir in the present invention is a hole provided in the polishing pad, and it is preferable that the polishing slurry is supplied from the hole to the polishing pad.

Further, the slurry pool in the present invention is
The holes may be holes provided in the polishing pad and the surface plate, and the polishing slurry may be supplied from the holes to the polishing pad.

Further, the slurry reservoir in the present invention is a container provided in the first rotating shaft portion, and the polishing slurry may be supplied from this container to the polishing pad.

Further, the chemical mechanical polishing apparatus according to the present invention comprises a surface plate which is rotationally driven about a first rotation axis, a polishing pad attached on the surface plate, and a first rotation axis. A carrier that is rotationally driven about an eccentric second rotation axis and holds a wafer and presses it against a polishing pad, a supply nozzle that supplies polishing slurry onto the polishing pad, and a tip position of the supply nozzle relative to the polishing pad. And an adjusting mechanism for adjusting manually.

With the above arrangement, the tip of the supply nozzle can be appropriately moved to adjust the supply position of the polishing slurry, and the polishing slurry can be spread evenly on the polishing pad. The feed nozzle can be configured to eject polishing slurry in multiple directions from the tip.
At this time, it is desirable that the adjusting mechanism be capable of adjusting the vertical position of the tip of the supply nozzle.

Further, the chemical mechanical polishing apparatus according to the present invention comprises a surface plate which is rotationally driven about a first rotation axis, a polishing pad attached on the surface plate, and a first rotation axis. A carrier that is rotationally driven about an eccentric second rotation axis, holds a wafer and presses it against a polishing pad, a supply nozzle that supplies polishing slurry onto the polishing pad, and a supply nozzle that is arranged at the center of the polishing pad. It is characterized in that the polishing slurry to be discharged is once stored and then is stored around the slurry.

The slurry pool is composed of a single hole formed in the polishing pad, or a first hole formed in the polishing pad and a second hole formed in the surface plate so as to communicate therewith, or , As a container placed on the polishing pad. When the slurry reservoir is composed of a container, a hole for accommodating a part of the container is formed in the polishing pad or the polishing pad and the surface plate, and the part of the container is inserted into the hole and arranged. May be.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Three embodiments of a chemical mechanical polishing (CMP) apparatus according to the present invention will be described below.

FIG. 1 is a side view showing a main part of a CMP apparatus according to the first embodiment, and FIG. 2 is a plan view. This CM
The main part of the P device is a surface plate 10 which is driven to rotate about a first rotation axis Ax1, a polishing pad 11 attached on the surface plate 10, and a second surface eccentric from the first rotation axis Ax1. It is driven to rotate about the rotation axis Ax2, and each wafer 1
Two sets of carriers 20, 20 which hold 2, 12 and press against the polishing pad 11, a supply nozzle 30 for supplying the polishing slurry 13 onto the polishing pad 11, and a tip position of the supply nozzle relative to the polishing pad 11. And an adjusting mechanism 40 for adjusting the target.

A backing plate 21 is fixed to the center of the carrier 20 as shown in an enlarged view in FIG. 3, and this backing plate 21 has a protruding portion having the same outer diameter as that of the wafer 12. A backing film 22 is attached to the lower side of the surface.

The wafer 12 has a backing film 22.
In close contact with the backing plate 21, it is fastened to the backing plate 21 by a clamp ring 24 via a retainer ring 23. That is, the retainer ring 23 is arranged so as to surround the outer periphery of the protruding portion of the backing plate 21 and the wafer 12, and the clamp ring 24 has a function of fixing the retainer ring 23 from the outside.

The backing plate 21 is a rigid body such as ceramic, and its lower surface has extremely high flatness. The backing film 22 is an elastic body such as foamed polyurethane, and has a function of maintaining high adhesion of the wafer 12 and a function of maintaining polishing uniformity by absorbing and dispersing shocks during polishing.

The adjusting mechanism 40 is, in this example, the supply nozzle 3
The tip position of 0 can be slid and adjusted independently of each other in the directions of the two orthogonal axes. That is, the adjusting mechanism 40
As shown in an enlarged view in FIG. 4, the two fixed rails 41, 41 arranged in parallel to each other and the fixed rail 41 are slid along the extending direction x of the fixed rail 41. It is composed of a movable frame 42 that can be moved and a holding member 43 that is attached to the movable frame 42 so as to be slidable in a direction y orthogonal to the sliding direction of the fixed frame 42. The tip of the supply nozzle 30 is fixed so as to penetrate almost the center of the holding member 43, and the moving frame 42 and the holding member 43 are slid to adjust the slurry supply position on the polishing pad 11 to the sliding range. It can be arbitrarily adjusted within.

According to the first embodiment, the supply nozzle 30
By adjusting the supply position of the polishing slurry by appropriately moving the tip of the polishing slurry according to the supply amount of the polishing slurry, the position of the wafer, etc., the polishing slurry can be spread evenly on the polishing pad 11, It is possible to suppress both the variation in the polishing amount within the wafer and the imbalance in the polishing rate among a plurality of wafers.

For example, when the supply amount (flow rate) of the polishing slurry per unit time is relatively large, the tip of the supply nozzle 30 is retracted as compared with the case where the flow rate is small, whereby the polishing slurry on the polishing pad 11 is removed. The supply position can be kept constant regardless of the flow velocity.

FIG. 5 shows a first modification of the first embodiment. In this example, the supply nozzle 31 in which only the tip portion is bent downward is used. Supply nozzle 3 of FIG.
1 is also attached to the adjusting mechanism 40 similar to the above-described embodiment. However, when the supply nozzle 31 of FIG. 5 is used, the slurry supply position can be kept constant even if the flow rate of the polishing slurry changes, so that the linear supply nozzle 30 of the first embodiment can be used. By comparison, the need for adjusting the nozzle position is reduced.

FIG. 6 shows a second modification of the first embodiment. In this example, the supply nozzle 3 having a plurality of supply holes 32a is formed so as to discharge the polishing slurry in multiple directions.
2 is used. Since the supply nozzle 32 disperses and discharges the polishing slurry in multiple directions, the difference in the flow rate of the polishing slurry corresponds to the size of the range in which the polishing slurry is dispersed.
The center of the dispersion range hardly changes. Therefore, in this case, as the adjusting mechanism, if the vertical position of the tip of the supply nozzle 32 can be adjusted, the range of the dispersion range can be changed. However, also in the modified example of FIG. 6, the position of the supply nozzle 32 may be adjusted by an adjustment mechanism that can be driven in two directions similar to the first embodiment. In this case, the positional accuracy of the supply nozzle 32 with respect to the polishing pad 11 is relaxed, and the adjusting means can be controlled with a lower accuracy than in the first embodiment.

FIG. 7 is a sectional view showing the main part of the CMP apparatus according to the second embodiment, and FIG. 8 is a plan view thereof. The CMP apparatus according to the second embodiment is eccentric from the surface plate 10 that is rotationally driven about the first rotation axis Ax1, the polishing pad 11 attached on the surface plate 10, and the first rotation axis Ax1. Two sets of carriers 20, 20 that are rotationally driven about the second rotation axes Ax2, Ax2 and hold the wafers 12, 12 respectively and press them against the polishing pad 11, and the polishing pad 1.
1, a supply nozzle 30 for supplying the polishing slurry 13 onto
A slurry reservoir 50 is disposed in the center of the polishing pad 11 and temporarily stores the polishing slurry discharged from the supply nozzle 30 and then discharges it to the surroundings. In this example, the slurry reservoir 50 is formed as a hole 11 a penetrating the polishing pad 11, and the polishing pad 11 with a hole is formed.
By sticking on the surface plate 10, a cylindrical container-like space having the upper surface of the surface plate 10 as the bottom surface and the periphery of the hole 11a as the side surface is formed, and this serves as the slurry reservoir 50.

The structure of the surface plate 10, the carrier 20, etc. is the same as that of the first embodiment, but a slurry reservoir 50 is provided, a supply nozzle 30 is fixedly provided, and an adjusting mechanism 40 is provided. The difference is that it is not.

In the first embodiment, when the flow rate of the polishing slurry increases, the polishing slurry may bounce on the surface of the polishing pad 11, making it difficult to uniformly supply the polishing slurry to the entire surface of the polishing pad. is there. In this regard, in the second embodiment, since the polishing slurry is stored in the slurry reservoir 50, there is no rebound on the surface of the polishing pad 11 even if the flow rate increases, and the polishing slurry is uniformly supplied to the entire surface of the polishing pad. It becomes possible.

According to the configuration of the second embodiment, the polishing slurry discharged from the supply nozzle 30 is temporarily stored in the slurry reservoir 50, and the amount of slurry supplied exceeding the capacity overflows from the slurry reservoir 50 and spreads around. . The spread of the polishing slurry is uniform irrespective of the direction of the supply nozzle 30, whereby the polishing slurry can be spread uniformly on the polishing pad 11, and variations in the polishing amount within a single wafer and It is possible to reduce the imbalance of the polishing rate among a plurality of wafers together.

Since the polishing pad 11 is a consumable item and is replaced at any time, the capacity of the slurry reservoir 50 can be easily changed by changing the size of the hole formed as necessary.

FIG. 9 is a sectional view showing a modification of the second embodiment. The CMP apparatus of the modified example has a surface plate 10 so as to communicate with the first hole 11a formed in the polishing pad 11.
Also, a second hole 10a is formed therein, and a slurry reservoir 51 for storing the polishing slurry is formed by these first and second holes 11a and 10a. According to this configuration,
Since the depth of the slurry pool can be made deeper than that in the second embodiment, even if the flow rate of the polishing slurry discharged from the supply nozzle 30 is large, the splashing of the polishing slurry can be prevented and the polishing slurry The uniformity of supply can be improved.

In order to change the capacity of the slurry reservoir 51, the sizes of the first and second holes 11a and 10a may be changed. However, the size of the first hole 11a formed in the polishing pad 11 can be changed by replacing the polishing pad 11, but the surface plate 10 cannot be replaced. Therefore, when using the CMP apparatus of the modified example of FIG.
By inserting a cylindrical filling member into the second hole 10a formed in No. 0 as needed, the inner diameter of the hole 10a is adjusted stepwise to adjust the volume of the polishing slurry stored in the slurry reservoir 51. 10 and 11 show the second hole 1
It is sectional drawing and the top view which show the state which inserted the 1st and 2nd filling member 60, 61 into 0a. First filling member 6
Reference numeral 0 denotes a cylindrical member having an outer diameter substantially equal to the inner diameter of the hole 10a and having a through hole formed in the center, and the second filling member 61 is fitted into the through hole of the first filling member 60. It is a cylindrical member having a matching outer diameter and having a through hole formed in the center. When the filling member is not used, the capacity of the slurry reservoir 51 is the largest, when the first filling member 60 alone is inserted, the intermediate volume, and when both the first and second filling members are inserted together, the minimum volume. It becomes capacity.

FIG. 12 is a CMP according to the third embodiment.
FIG. 13 is a cross-sectional view showing the main part of the device, and FIG. 13 is a plan view thereof. The CMP apparatus of the third embodiment includes a surface plate 10, a polishing pad 11, two sets of carriers 20, 20, a supply nozzle 30, and a slurry reservoir 52, like the apparatus of the second embodiment. In this example, the slurry reservoir 52 is configured as a bottomed cylindrical container 70 arranged on the polishing pad 11.

The container 70 is attached to the upper surface of the polishing pad 11, the polishing slurry discharged from the supply nozzle 30 is temporarily stored in the container 70, and the amount of the slurry supplied exceeding the capacity overflows from the container 70 to the surroundings. spread. Similar to the second embodiment, the spread of the polishing slurry is caused by the supply nozzle 30.
Is uniform irrespective of the orientation of the polishing pad, whereby the polishing slurry can be spread evenly on the polishing pad 11, the variation in the polishing amount within a single wafer, and the polishing rate between a plurality of wafers can be improved. Both imbalances can be kept small. Further, since it is not necessary to process the polishing pad 11 and the surface plate 10 and the installation position of the container 70 can be arbitrarily selected according to the flow rate of the polishing slurry and the like, the degree of freedom is high and more types of CMP processes are possible. Can correspond to.

FIG. 14 shows a modification of the above-described third embodiment, which is a combination of the modification of the second embodiment shown in FIG. That is, the polishing pad 11 and the surface plate 10 have first and second holes 11 a, 1 that communicate with each other.
0a is formed, and a bottomed cylindrical container 71 having a depth higher than the depth of the hole is inserted and fixed in these holes to form a slurry reservoir 53. According to this configuration, the hole 11
The depth of the slurry pool can be made deeper than when a and 10a are directly used as the slurry pool, and the jumping up when the flow rate of the polishing slurry is large can be more effectively prevented.

[0038]

As described above, C according to the present invention
According to the MP apparatus, by providing the adjusting mechanism for adjusting the tip position of the supply nozzle relative to the polishing pad, the tip of the supply nozzle can be appropriately moved to adjust the supply position of the polishing slurry. The polishing slurry can be spread evenly on the polishing pad.

According to the present invention, the polishing slurry can be discharged in multiple directions from the tip of the supply nozzle, and the difference in the flow rate of the polishing slurry is that the polishing slurry is dispersed. In order to correspond to the wide range of the dispersion range, the adjustment mechanism can change the dispersion range if the vertical position of the tip of the supply nozzle can be adjusted.

According to the CMP apparatus of the present invention,
At the center of the polishing pad, there is a slurry pool that temporarily stores the polishing slurry discharged from the supply nozzle and then discharges it to the surroundings.Therefore, even if the flow rate of the polishing slurry increases, there is no bounce on the surface of the polishing pad and It becomes possible to uniformly supply the polishing slurry to the entire surface of the pad.

When a single hole formed in the polishing pad is used as a slurry reservoir, only the polishing pad, which is a consumable item, can be processed. Therefore, most of the conventional apparatus can be used.

When the slurry pool is composed of the first hole formed on the polishing pad and the second hole formed on the surface plate so as to communicate with the first hole, the depth of the slurry pool is increased. Therefore, even when the flow rate of the polishing slurry discharged from the supply nozzle is high, the splashing of the polishing slurry can be prevented and the uniformity of the supply of the polishing slurry can be further improved.

When a container arranged on the polishing pad is used as a slurry reservoir, it is not necessary to process the polishing pad or the surface plate, and the installation position of the container can be arbitrarily selected according to the flow rate of the polishing slurry. Therefore, the degree of freedom is high,
More kinds of CMP processes can be supported.

When a part of the container is placed in the polishing pad or inserted in the hole formed with the polishing pad and the surface plate, the hole of the slurry reservoir is used rather than the hole being directly used as the slurry reservoir. The depth can be increased, and the jumping up when the flow rate of the polishing slurry is high can be more effectively prevented.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of a CMP apparatus according to a first embodiment.

FIG. 2 is a plan view of the CMP apparatus shown in FIG.

3 is an enlarged sectional view of a carrier portion of the CMP apparatus shown in FIG.

FIG. 4 is an enlarged view of an adjusting mechanism portion of the CMP apparatus shown in FIG.

FIG. 5 is a CMP according to a first modified example of the first embodiment.
The side view which shows the principal part of an apparatus.

FIG. 6 is a side view of a supply nozzle showing a second modification of the first embodiment.

FIG. 7 is a sectional view showing a main part of a CMP apparatus according to a second embodiment.

FIG. 8 is a plan view of the CMP apparatus shown in FIG.

FIG. 9 is a cross-sectional view showing a modified example of the second embodiment.

10 is a sectional view of a surface plate portion of the CMP apparatus shown in FIG.

11 is a plan view of a surface plate portion of the CMP apparatus shown in FIG.

FIG. 12 is a sectional view showing a main part of a CMP apparatus according to a third embodiment.

13 is a plan view of the CMP apparatus shown in FIG.

FIG. 14 is a cross-sectional view of a CMP apparatus showing a modification of the third embodiment.

FIG. 15 is a side view showing a main part of a conventional CMP apparatus.

16 is a plan view of the CMP apparatus shown in FIG.

[Explanation of symbols]

10 surface plate 11 polishing pad 12 wafers 20 career 30, 31, 32 supply nozzle 40 adjustment mechanism 50 slurry pool 70 containers

Claims (7)

[Claims] 1. A carrier rotatably driven around a second rotation axis eccentric from the first rotation axis on a polishing pad attached on a surface plate rotatably driven around a first rotation axis. Of the wafer characterized by including the step of pressing the wafer with the step of driving the surface plate and the carrier to polish the wafer, and the step of supplying the polishing slurry onto the polishing pad while moving the nozzle. Polishing method. 2. The method of polishing a wafer according to claim 1, wherein the tip of the nozzle has a shape bent downward. 3. The method of polishing a wafer according to claim 1, wherein a plurality of supply holes are formed at the tip of the nozzle. 4. A carrier rotatably driven around a second rotation axis eccentric from the first rotation axis on a polishing pad attached on a surface plate rotatably driven around the first rotation axis. The step of pressing the wafer with the step of driving the surface plate and the carrier to polish the wafer, and supplying the polishing slurry to the slurry reservoir provided in the rotating shaft portion, and polishing the slurry pad from the slurry reservoir to the polishing pad. And a step of discharging a slurry. 5. The method of polishing a wafer according to claim 4, wherein the slurry reservoir is a hole provided in the polishing pad, and the polishing slurry is supplied from the hole to the polishing pad. 6. The wafer polishing according to claim 4, wherein the slurry reservoir is a hole provided in the polishing pad and the surface plate, and polishing slurry is supplied to the polishing pad through the hole. Method. 7. The slurry reservoir is a container provided in the first rotating shaft portion, and the polishing slurry is supplied from the container to the polishing pad.
The method for polishing a wafer according to.