JPH11347940A - Polishing slurry reproducing device and polishing system using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform washing of a filter and its replacement easily without lowering the rate of operation of a polishing device. SOLUTION: A polishing slurry regenerating device 20 is equipped with a plurality of filters 34a and 34b to remove foreign matter from the polishing slurry having done its work, filter selecting means 32a and 32b to supply the used polishing slurry to one of the filters 34a and 34b selectively, and a slurry sendout means 52, etc., to supply the regenerated slurry having passed the filter to the polishing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing system for flattening the surface of a flat substrate such as a semiconductor wafer using a polishing slurry. In particular, the present invention relates to an improvement in a slurry recycling apparatus for recycling used polishing slurry used in a polishing apparatus.

[0002]

2. Description of the Related Art As semiconductor devices become more highly integrated, it is required to flatten the surface of a semiconductor wafer with higher precision than ever before. At present, CMP equipment (chemical mechanical polishing equipment) is used as an equipment for flattening the surface of a wafer.
Is widely used. Generally, in a CMP apparatus, a polishing slurry is supplied between a rotating polishing pad and a semiconductor wafer. Since polishing slurries are expensive, methods for recycling used polishing slurries have already been proposed.

Generally, in a polishing slurry regenerating (circulating) apparatus, used polishing slurry that has passed through a filter and is filtered is accumulated in a regenerating tank, and is returned to the CMP apparatus when a certain amount is accumulated.

[0004]

In the conventional polishing slurry regenerating apparatus, when the filter is clogged due to long-time operation, the operation of the polishing apparatus is temporarily stopped. Then, the filter is washed, and the cleaned filter is set in the regenerating device, and then the operation of the polishing device is restarted.

As described above, since the operation of the polishing apparatus is stopped during the cleaning of the filter, there is a problem that the operation rate of the polishing apparatus is reduced. There is a similar problem when replacing an old filter.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and provides a polishing slurry regenerating apparatus capable of easily performing filter cleaning and replacement operations without lowering the operation rate of the polishing apparatus. The purpose is to:

Another object of the present invention is to provide a polishing system provided with a polishing slurry regenerating device capable of easily performing filter cleaning and replacement operations without lowering the operation rate of the polishing device.

[0008]

In order to solve the above problems, a polishing slurry regenerating apparatus (20) according to a first aspect of the present invention comprises a plurality of filters (for removing foreign substances contained in used polishing slurry). 34a, 34b); a plurality of filters (34a, 34b) used polishing slurry
Filter selection means (32a, 32b) for selectively supplying the regenerated polishing slurry to the polishing apparatus (12). I have.

A polishing system (10) according to a second aspect of the present invention includes: a polishing apparatus (12) for polishing a flat substrate surface with a polishing pad; and supplying a polishing slurry to the polishing apparatus (12). Slurry supply means (18);
Collecting means (26a, 26b) for collecting the polishing slurry used in the polishing apparatus (12); a plurality of filters (34a, 34b) for removing foreign substances contained in the collected used polishing slurry; Filter selection means (32a, 32b) for selectively supplying to one of the plurality of filters (34a, 34b). Then, the regenerated polishing slurry that has passed through the filters (34a, 34b) is supplied to the polishing apparatus (12) via the slurry supply means (18).

In the first and second aspects of the present invention as described above, each of the plurality of filters (34a, 34b) can independently store the used slurry before passing through the filters. Filter tank (74
a, 74b) (24, 24a, 24)
b) can be provided. Further, the filter selecting means can be constituted by switching means (32a, 32b) for switching the flow path of the polishing slurry so as to supply the polishing slurry to another filter when replacing the filter in use.

Preferably, a plurality of filters (34a,
34b) in each of the regeneration containers (24, 24a, 24b).
To a cartridge (64) that can be easily attached to and detached from. Further, it is preferable that each of the plurality of filters (34a, 34b) is arranged to be inclined at a predetermined angle with respect to the horizontal.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to examples. In the embodiments described below, the technical idea of the present invention is applied to a CMP apparatus for polishing the surface of a semiconductor wafer. It is needless to say that the present invention can be applied to polishing of various types of flat samples such as a magnetic disk and a glass substrate in addition to polishing of a semiconductor wafer.

[0013]

FIG. 1 shows the overall configuration of a CMP system according to an embodiment of the present invention. The CMP system 10 is roughly divided into a CMP apparatus main body 12 and a slurry supply unit (14 to 24) for supplying a polishing slurry to the CMP apparatus 12. CMP
The apparatus main body 12 polishes the surface of the semiconductor wafer using a polishing pad by a well-known configuration as shown in, for example, Japanese Patent Application Laid-Open No. 5-285825. During the polishing operation, a polishing slurry is supplied between the polishing pad and the semiconductor wafer.

The polishing slurry supply units (14 to 24)
A slurry supply source 14 that supplies a new slurry stock solution that is not reused, and a slurry stock solution supplied from the slurry supply source 14 is mixed with a diluent or an additive such as pure water at a predetermined ratio,
A slurry mixing unit 16 for adjusting the concentration to a predetermined value. The polishing slurry supplied from the slurry mixing unit 16 is sent to the slurry supply unit 18.

On the other hand, the used slurry discharged from the CMP apparatus main body 12 is supplied to a discharge unit 24 and a regeneration unit 20. The slurry supplied to the discharge unit 24 is a slurry that does not have an appropriate concentration, such as a polished wafer or a discharged slurry immediately after the CMP apparatus main body 12 is washed with pure water, and is discarded without being recycled. On the other hand, the slurry supplied to the regeneration unit 20 is a slurry having an appropriate concentration, and is returned to the slurry supply unit 18 after the filtration and regeneration processing is performed. The detailed configuration of the reproduction unit 20 will be described later.

The slurry supply unit 18 includes a new polishing slurry supplied from the slurry mixing unit 16;
The regenerated slurry supplied from the regenerating unit 20 is mixed and supplied to the filter unit 22. The filter unit 22 filters the polishing slurry immediately before being supplied to the CMP apparatus main body 12.

Next, the overall operation of the CMP system 10 configured as described above will be briefly described. The stock slurry supplied from the slurry supply source 14 to the slurry mixing unit 16 is mixed with pure water at a predetermined ratio, and then sent to the slurry supply unit 18.

On the other hand, it is discharged from the CMP apparatus main body 12 and
The used slurry supplied to the regeneration unit 20 is subjected to filtration and regeneration treatment in the regeneration unit 20,
The regenerated slurry is supplied to the slurry supply unit 18.

The new slurry supplied from the slurry mixing unit 16 and the regenerated slurry supplied from the regenerating unit 20 are mixed in the slurry supplying unit 18 and then sent to the filter unit 22.
Then, the slurry filtered again by the filter unit 22 is supplied to the CMP apparatus main body 12.

FIG. 2 shows a detailed configuration of the above-mentioned reproducing unit 20. The main feature of the present invention is that the reproduction unit 2
Exists in 0. The regenerating unit 20 plays a role as a slurry regenerating device, and includes first and second regenerating containers 24a and 24b for regenerating used slurry.
And pipes 26a and 26b for guiding the used slurry recovered from the CMP apparatus main body 12 to the first and second regeneration vessels 24a and 24b, respectively.

A valve 32a is provided at a connection portion of the pipe 26a with the first regeneration container 24a. Similarly, a valve 3 is connected to the connection between the pipe 26b and the second regeneration container 24b.
2b is provided. These valves 32a, 32b
Is that one is closed and the other is released,
The valve is selectively opened and closed, and a manual valve or an electromagnetic valve can be used. In this embodiment, an electromagnetic valve is used.

A filter 34a is disposed inside the first regeneration container 24a. Similarly, the second regeneration container 24b
A filter 34b is arranged inside. As these filters 34a and 34b, for example, 100
A mesh or a filter having a roughness of 200 mesh can be used. Each of the filters 34a and 34b is arranged at an inclination of about 30 degrees with respect to the horizontal. Note that the inclination angles of the filters 34a and 34b are desirably determined in consideration of the roughness of the filters, the viscosity of the slurry, and the like, and can be set, for example, in the range of 10 to 60 degrees. The filters 34a, 34b
Is actually mounted on a cartridge as shown in FIG. 3, and its configuration will be described later.

By inclining the filters 34a and 34b, the used slurry can be easily spread over the entire surface of the filter, and the filter surface can be used effectively, so that the effect of extending the life of the filter can be expected.

The inside of the first regeneration container 24a contains a filter 34.
a first filter tank 74a, which is above the a and in which used slurry is supplied and can store the slurry before passing through the filter 34a, and a first filter tank 74a which stores the slurry after passing through the filter 34a below the filter 34a. It is divided into one regeneration tank 76a. Similarly, inside the second regeneration container 24b, the second filter tank 74b and the second
And a regeneration tank 76b.

The upper portions of the first filter tank 74a and the second filter tank 74b are connected by an overflow line 36. And, when the slurry is about to overflow in the filter tank in the regeneration vessel during the filtration operation in one regeneration vessel, the slurry that is about to overflow is automatically transferred to the other regeneration vessel. It is to be sent.

Three sensors 38a, 40a and 42a are inserted in the first regeneration container 24a. Sensor 3
8a is a float type lower limit sensor,
It detects that the level of the slurry inside has reached the pumping stop position. When the pumping stop position is detected by the lower limit sensor 38a, the discharge (suction) of the slurry by the pump 52 is stopped. The sensor 40a is a float type upper limit sensor,
It detects that the level of the slurry in the regeneration tank 76a has reached the pumping start position.

When the pumping start position is detected by the upper limit sensor 40a, the pump 52 starts discharging (sucking) the slurry. The sensor 42a is an overflow sensor, detects the upper limit position of the slurry in the filter tank 74a, issues an alarm when the slurry reaches the position of the sensor 42a, and controls the valves 32a and 32b, The regeneration container to be used is changed.

In the second regenerating container 24b, three sensors 38b, 40b and 42 are provided similarly to the first regenerating container 24a.
b is arranged. The sensor 38b is a float-type lower limit sensor, and detects that the level of the slurry in the regeneration tank 76b has reached the pumping stop position. When the pumping stop position is detected by the lower limit sensor 38b, the discharge (suction) of the slurry by the pump 52 is stopped. The sensor 40b is a float type upper limit sensor, and detects that the level of the slurry in the regeneration container 24b has reached the pumping start position.

When the pumping start position is detected by the upper limit sensor 40b, the pump 52 starts discharging (sucking) the slurry. The sensor 42b is an overflow sensor, detects the upper limit position of the slurry in the filter tank 74a, issues an alarm when the slurry reaches the position of the sensor 42b, and controls the valves 32a and 32b, The regeneration container to be used is changed.

A drain pipe 44a is connected to the first regenerating vessel 24a, and the slurry in the regenerating vessel 76a is discharged (discarded) to a receiving tray 46a via a valve 48a as required. . Similarly to the first regeneration container 24a, the second regeneration container 24b is also connected to the drain pipe 44b, and discharges (disposes) the slurry in the regeneration tank 76b to the tray 46b via the valve 48b as necessary.
It is supposed to.

The first regeneration tank 76a has a regeneration pipe 50a
Are connected at one end. The multi-end of the regeneration pipe 50a
It is connected to the magnet type pump 52 via a valve 54a and a check valve 56a. And the valve 54
By driving the pump 52 with a opened, the slurry in the first regeneration tank 76a is sucked up.

As in the case of the first regeneration tank 76a, one end of the regeneration pipe 50b is connected to the second regeneration tank 76b. The multi-end of the regeneration pipe 50b includes a valve 54b and a check valve 56b.
Is connected to the pump 52 via the. Then, by driving the pump 52 with the valve 54b opened, the slurry in the second regeneration tank 76b is sucked up. The first and second regenerating containers 24a and 24b are each formed of a transparent acrylic plate into a quadrangular prism shape so that the internal state can be easily observed.

A circulation pipe 58 and a waste pipe 60 are connected to the pump 52. Usually, the slurry pumped by the pump 52 is sent to the slurry supply unit 18 (FIG. 1) through the circulation pipe 58. It has become. On the other hand, when the slurry in the regenerating tanks 76a and 76b is emptied, the slurry remaining in the regenerating tanks 76a and 76b that cannot be completely discharged from the drain pipe 44a is discharged from the waste pipe 60. Each of the above-mentioned pipes is made of an acid-resistant (slurry-resistant) material such as vinyl chloride (for example, polypropylene).

FIG. 3 shows the structure of the cartridge 64 of the filter 34a set in the first regeneration container 24a. FIG. 4 shows the inside of the regeneration container 24a in which the cartridge 64 is set. The second regeneration container 2
Since the same cartridge is used for the filter 34b in the filter 4b, only the cartridge 64 of the filter 34a will be described here. The filter cartridge 64 includes a cartridge main body 66 for holding the filter 34a, and a handle 7 provided with the main body 66 installed in the regeneration container 24a and further provided for easy removal.
0 and 72.

The cartridge main body 66 includes the first regeneration container 2.
The outer peripheral portion is formed in a flange shape so as to be held well with respect to the protrusion 82 projecting inward of 4a. An opening 72a is provided at an upper portion of the handle 72 so that the operator can easily grasp the opening 72a. (Handle 70
The same applies)

As shown in FIG. 4, a cartridge 64 is set in the first regeneration container 24a. First regeneration container 24a
Is a first filter tank 74a in which used slurry is supplied through a pipe 26a and is separated from the filter 34a by a partition plate 84, and a first filter tank 74a for storing the slurry after being filtered by the filter 34a. Regeneration tank 76
a. When the filter 34a is clogged, the filter tank 74a
A certain amount of used slurry before passing through can be stored. The overflow line 36 is connected to the upper part of the filter tank 74a,
Before the used slurry stored in the filter tank 74a overflows, it can flow out to the other filter tank 74b. Sensor 42a is in filter tank 74a, and sensors 38a and 40a are in regeneration tank 76a.
It is installed in. For convenience of explanation, FIG. 4 shows only the sensor 38a.

FIG. 5 shows a configuration of a control system of the slurry regenerating apparatus (regenerating unit) of the present embodiment. The slurry regenerating apparatus is generally controlled by a controller 90. Each sensor (38a, 40a, 42a, 38b, 40b, 42b) inserted into the first and second regeneration containers 24a, 24b as input data to the controller 90.
Are supplied. The controller 90 controls these sensors (38a, 40a, 42a, 38b, 40b,
Based on the data from 42b), the valves 32a, 54
a, 32b, 54b and the pump 52 as well as an alarm 92.

Next, the method of use and operation of the slurry regenerating apparatus 20 configured as described above will be described. First, in order to use the first regeneration container 24a, the valve 32a is opened and the valve 32b is closed under the control of the controller 90. As a result, the used slurry sent from the CMP apparatus main body 12 is supplied only to the first filter tank 74a via the pipe 26a. First
The used slurry supplied into the filter tank 74a flows along the slope of the filter 34a of the filter cartridge 64, and at the same time, passes through the filter 34a, is filtered, and falls downward.

When the upper limit sensor 40a detects that the amount (level) of the slurry in the first regenerating tank 76a has reached the pumping start position, the controller 90 sets the valve 5
4a is opened to start the operation of pumping the regenerated slurry by the pump 52. On the other hand, when the lower limit sensor 38a detects that the amount (level) of the slurry in the first regeneration tank 76a has reached the pumping stop position, the controller 90 closes the valve 54a and stops the pump 52 from pumping the regenerated slurry. I do.

The first regeneration tank 74 is driven by driving the pump 52.
The regenerated slurry pumped from a
Is supplied to the slurry supply unit 18 (FIG. 1). In such a circulation operation of the slurry, the first filter tank 7 may be removed due to clogging of the filter 34a or the like.
If the amount of slurry in 4a continues to increase and overflow sensor 42a is activated, controller 90 activates alarm 92 and simultaneously closes valve 32a and opens valve 32b. Here, the overflow sensor 42a does not operate normally or the filter 34
When the slurry rises rapidly due to clogging or the like, the slurry in the first filter tank 74a is supplied to the second filter tank 74b via the overflow line 36.

When the alarm 92 is activated, or when the operator determines that the filter 43a needs to be cleaned, the valve 32a is closed and the valve 32b is opened under the control of the controller 90, whereby
The flow path of the used slurry collected from the CMP apparatus main body 12 is switched to the second regeneration container 24b. And the second
While the used slurry is being filtered using the regeneration container 24b, the filter cartridge 64 of the first regeneration container 24a is removed, and the filter 34a is washed. Here, it is also possible to remove the entire first regeneration container 24a from the apparatus and completely clean the inside of the container 24a.

FIG. 6 shows a slurry regenerating apparatus according to a second embodiment. The regenerating apparatus shown in FIG. 6 differs from the first embodiment in that a regenerating tank for storing the slurry after passing through the two filters 34a and 34b is shared.
Two filter tanks in one regeneration vessel 24, that is, a first filter vessel 74a formed by a partition plate, a regeneration vessel inner wall, a filter cartridge 64a, and a filter 34a, a partition plate, a regeneration vessel inner wall, a filter cartridge 64b, and a filter A second filter tank 74b formed by 34b is formed.

The first filter tank 74a has a pipe 26a.
However, the pipe 26b is connected to the second filter tank 74b, and the used slurry is supplied to one of the filter tanks by controlling the valves 32a and 32b. The first filter tank 74a and the second filter tank 74b are connected by an overflow line 35. The sensors 38 and 40 are inserted into the regeneration tank 76, and the overflow sensors 42a and 42b are connected to the filter tanks 74a and 74b, respectively.
b. Other uses and functions are the same as those in the first embodiment.

[0044]

As described above, according to the present invention,
The washing and replacement work of the filter of the slurry regenerating apparatus can be easily performed without lowering the operation rate of the CMP apparatus. That is, even when the filter is clogged due to long-term operation, the filter can be washed or replaced without stopping the operation of the polishing apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a CMP according to a first embodiment of the present invention;
FIG. 1 is a schematic diagram illustrating an entire configuration of a system.

FIG. 2 is an explanatory diagram illustrating a configuration of a slurry regenerating apparatus (regenerating unit) according to the first embodiment.

FIG. 3 is a perspective view illustrating a configuration of a filter cartridge according to the first embodiment.

FIG. 4 is a sectional view showing a use state of the filter cartridge shown in FIG. 3;

FIG. 5 is a block diagram illustrating a configuration of a control system of the slurry regenerating apparatus (regenerating unit) according to the first embodiment;

FIG. 6 is an explanatory diagram showing a configuration of a slurry regenerating apparatus (regeneration unit) according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... CMP system 12 ... CMP apparatus main body 18 ... Slurry supply unit 20 ... Regeneration unit 24a, 24b ... Regeneration container 34a, 34b ... Filter 32a, 32b ... Valve 64. ..Filter cartridges

Claims (17)

[Claims] An apparatus for regenerating a polishing slurry used in a polishing apparatus, comprising: a plurality of filters for removing foreign substances contained in a used polishing slurry; and a method for applying the used polishing slurry to one of the plurality of filters. A polishing slurry regenerating apparatus, comprising: a filter selecting means for selectively supplying the regenerated polishing slurry having passed through the filter to the polishing apparatus. 2. The apparatus according to claim 1, further comprising a regeneration vessel having a filter tank capable of independently storing the used slurry before passing through the filters, for each of the plurality of filters. 2. The polishing slurry regeneration device according to 1. 3. A filter tank capable of independently storing the used slurry before passing through the filter for each of the plurality of filters, and a regenerating tank storing polishing slurry after passing through the filter. The polishing slurry regenerating apparatus according to claim 1, wherein the regenerating vessels having the following are provided independently of each other. 4. A polishing slurry regenerating apparatus according to claim 1, wherein said filter selecting means is a switching means for switching a flow path of said polishing slurry. 5. The polishing slurry regenerating apparatus according to claim 2, wherein each of the plurality of filters is mounted on a cartridge that can be easily attached to and detached from the regenerating container. 6. The polishing slurry recycling apparatus according to claim 1, wherein each of the plurality of filters is arranged at a predetermined angle with respect to the horizontal. 7. An inclination angle of the filter is from 10 degrees to 6 degrees.
The polishing slurry regenerating apparatus according to claim 6, wherein the angle is 0 degree. 8. When the polishing slurry in the filter tank to which the filter in use is attached has reached a predetermined level or more, surplus polishing slurry in the filter tank is automatically sent to another filter tank side. 5. The method according to claim 2, further comprising an overflow path.
The polishing slurry regenerating apparatus according to 5, 6, or 7. 9. A polishing apparatus for polishing a flat substrate surface with a polishing pad; a slurry supply means for supplying a polishing slurry to the polishing apparatus; and a collecting means for collecting the polishing slurry used in the polishing apparatus. A plurality of filters for removing foreign substances contained in the collected used polishing slurry; and a filter selecting means for selectively supplying the used polishing slurry to one of the plurality of filters, A polishing system, wherein a regenerated polishing slurry that has passed through a filter is supplied to the polishing apparatus via the slurry supply unit. 10. The polishing apparatus according to claim 9, wherein said slurry supply means is configured to mix said regenerated polishing slurry and new polishing slurry at a predetermined ratio and to supply them to said polishing apparatus. system. 11. A regenerating container having a filter tank capable of independently storing the used slurry before passing through the filters, for each of the plurality of filters. The polishing system according to 9 or 10. 12. A filter tank capable of independently storing the used slurry before passing through the filter for each of the plurality of filters, and a regenerating tank storing polishing slurry after passing through the filter. 11. The polishing system according to claim 9, wherein regeneration vessels each comprising 13. The polishing system according to claim 9, wherein said filter selecting means is switching means for switching a flow path of said polishing slurry. 14. The polishing system according to claim 11, wherein each of said plurality of filters is mounted on a cartridge which is easily detachable from said regeneration container. 15. The polishing system according to claim 9, wherein each of the plurality of filters is arranged at a predetermined angle with respect to the horizontal. 16. An inclination angle of the filter is 10 degrees or more.
The polishing system according to claim 15, wherein the angle is 60 degrees. 17. When the polishing slurry in the filter tank to which the used filter is attached reaches a predetermined level or more, the surplus polishing slurry in the filter tank is automatically sent to another filter tank side. 11. The method according to claim 9, further comprising an overflow path.
The polishing system according to claim 11, 12, 13, 14, 15, or 16.