JPH0740232A - Polishing device and polishing method - Google Patents

Abstract

PURPOSE:To improve the productivity and reduce the running cost. CONSTITUTION:A polishing pad 17 with water permeability with a large number of cavity parts formed inside is adhered on a rotary surface plate 10 manufactured of porous ceramics, a polishing liquid supply passage 11 is provided inside of the rotary surface plate 10, the polishing liquid supply passage 11 is connected to a polishing liquid supply source (not graphically displayed), and the rotary surface plate 10 is installed on an axis of rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and a polishing method for polishing the surface of a workpiece such as a semiconductor wafer.

[0002]

2. Description of the Related Art One of the steps for manufacturing a semiconductor integrated circuit is a step of flattening fine irregularities on the surface of a semiconductor wafer before a wiring step. In this step, a chemical mechanical polishing apparatus with low processing cost is used. It is used. This chemical mechanical polishing apparatus is the same as a general mechanical polishing apparatus, except that a polishing liquid containing a component having a chemical action on a semiconductor wafer is used.

FIG. 4 is a schematic view showing a conventional chemical mechanical polishing apparatus. As shown in the figure, the rotary shaft 13 is attached to the output shaft of the motor 9, the rotary platen 2 is attached to the rotary shaft 13, the polishing pad 1 is stuck on the surface of the rotary platen 2, and the rotary holder 4 The semiconductor wafer 3 is attached to the polishing pad 1, and the polishing liquid supply nozzle 5 is provided above the polishing pad 1.

In this polishing apparatus, the rotary platen 2 and the polishing pad 1 are rotated by operating the motor 9, and the semiconductor wafer 3 is pressed against the polishing pad 1 while being rotated by the rotary holder 4, and the polishing liquid is supplied. By supplying the polishing liquid in which the slurry is suspended from the nozzle 5 onto the polishing pad 1, the surface of the semiconductor wafer 3 can be polished.

[0005]

However, in this polishing apparatus, as shown in FIG. 5, in the fine recesses 6 on the polishing surface of the polishing pad 1, the polishing powder 7 of the semiconductor wafer 3 and the slurry solid in the polishing liquid are formed. Since the object 8 is clogged and the processing efficiency is gradually reduced, the productivity is deteriorated. Therefore, the polishing pad 1
In order to remove the clogging of the polishing pad, it is necessary to clean and sharpen the polishing surface of the polishing pad 1 for each processing, so-called conditioning work, and it is necessary to replace and replace the polishing pad every day. Is high.

The present invention has been made to solve the above problems, and an object thereof is to provide a polishing apparatus and a polishing method which have good productivity and low running costs.

[0007]

In order to achieve this object, in the present invention, in a polishing apparatus for performing relative movement while pressing a workpiece on the polishing surface of the polishing pad, water permeability is used as the polishing pad. Using what is provided, polishing is performed while supplying a polishing liquid from the back surface of the polishing pad to the polishing surface of the polishing pad.

In this case, the polishing pad is attached on a rotary platen made of a porous material, and the polishing liquid is supplied to the polishing pad from inside the rotary platen.

In this case, the rotary platen made of porous ceramics is used.

Further, a plurality of polishing liquid supply systems are provided.

The polishing pad is attached on a rotary platen made of a porous material, and a static pressure floating pad is provided on the back surface of the rotary platen.

Further, in the polishing method in which the workpiece is pressed against the polishing surface of the polishing pad to perform relative motion, a polishing pad having water permeability is used,
Processing is performed while supplying a polishing liquid from the back surface of the polishing pad to the polishing surface of the polishing pad.

In this case, the polishing pad is attached on a rotary surface plate made of a porous material, a static pressure floating pad is provided on the back surface of the rotary surface plate, and the polishing liquid is discharged from the static pressure floating pad. It is supplied to a rotary platen and subjected to polishing while compensating the pressing force of the workpiece to the polishing pad.

[0014]

In this polishing apparatus and polishing method,
Since the polishing liquid is supplied from the back surface of the polishing pad to the polishing surface of the polishing pad, it is possible to prevent the polishing powder of the semiconductor wafer and the slurry solids in the polishing liquid from being clogged in the fine recesses of the polishing surface of the polishing pad. Moreover, it is not necessary to perform conditioning work for each processing, and it is not necessary to replace and replace the polishing pad every day.

When the polishing pad is attached on a rotary platen made of a porous material and the polishing liquid is supplied to the polishing pad from the rotary platen, the temperature of the polishing liquid is set to a predetermined condition. By supplying it, the rotary platen can be brought to a predetermined temperature.

When the rotary platen made of porous ceramics is used, the rotary platen can be easily manufactured.

When a plurality of polishing liquid supply systems are provided, the type of polishing liquid can be changed during polishing.

Further, when the polishing pad is attached on a rotary platen made of a porous material and a static pressure levitation pad is provided on the back surface of the rotary platen, the thickness of the rotary platen can be reduced. .

Further, the polishing pad is attached on a rotary surface plate made of a porous material, a static pressure levitation pad is provided on the back surface of the rotary surface plate, and the polishing liquid is supplied from the static pressure levitation pad to the rotary surface plate. When polishing is performed while compensating the pressing force of the work piece against the polishing pad, the amount of polishing liquid used can be reduced.

[0020]

1 is a schematic sectional view showing a part of a polishing apparatus according to the present invention. As shown in the figure, a water-permeable polishing pad 17 having a large number of cavities formed therein is attached onto a rotary platen 10 made of porous ceramics, and the polishing liquid is placed inside the rotary platen 10. A supply path 11 is provided, the polishing solution supply path 11 is connected to a polishing solution supply source (not shown), and the rotary platen 10 is attached to a rotary shaft 13.

Next, a method of polishing a semiconductor wafer with the polishing apparatus shown in FIG. 1 will be described. First, by operating the motor, the rotating surface plate 10,
When the polishing pad 17 is rotated and the semiconductor wafer 3 is rotated by the rotary holder and pressed against the polishing pad 17, and the polishing liquid 12 is supplied to the polishing liquid supply path 11, the polishing liquid 1
2 passes through the holes of the rotary platen 10 and further passes through many cavities existing inside the polishing pad 17, reaches the polishing surface of the polishing pad 17, and the surface of the semiconductor wafer 3 is polished. . The pressure for supplying the polishing liquid 12 is preferably such that the polishing liquid 12 slightly exudes when the semiconductor wafer 3 is pressed against the polishing surface of the polishing pad 17.

In such a polishing apparatus and polishing method, since the polishing liquid 12 is supplied from the back surface of the polishing pad 17 to the polishing surface of the polishing pad 17, the semiconductor wafer 3 is placed in the fine recesses on the polishing surface of the polishing pad 17. Since it is possible to prevent clogging of the polishing powder and the slurry solids in the polishing liquid, the processing efficiency does not decrease, the productivity is good, and it is necessary to perform conditioning work for each processing. Since it does not exist, the life of the polishing pad 17 can be extended and the running cost can be reduced. Further, since the polishing liquid is supplied to the polishing pad 17 from the inside of the rotary platen 10, it is possible to bring the rotary platen 10 to a predetermined temperature by setting the temperature of the polishing liquid 12 to a predetermined condition and supplying the same. Therefore, stable polishing can be performed. Further, since the rotary platen 10 made of porous ceramics is used, the rotary platen 10 can be easily manufactured, so that the manufacturing cost is low. Further, since the amount of the expensive polishing liquid 12 used is about half that of the polishing apparatus shown in FIG. 4, the polishing processing cost can be reduced. Further, since it is possible to prevent the fine recesses on the polishing surface of the polishing pad 17 from being clogged with polishing powder or the like of the semiconductor wafer 3, it is possible to reduce the frequency of occurrence of scratches on the semiconductor wafer 3. Further, if pure water or the like is supplied instead of the polishing liquid 12 after the processing work, the polishing pad 17 can be cleaned without brushing, so that the polishing pad 17 need not be replaced every day.

FIG. 2 is a schematic partial sectional view showing a part of another polishing apparatus according to the present invention. As shown in the figure, the rotary shaft 13 of the rotary platen 10 is provided with polishing liquid supply paths 11a and 11b connected to the polishing liquid supply path 11, and the polishing liquids 12a and 12b are supplied to the polishing liquid supply paths 11a and 11b. Rotating shaft seals 14a and 14b are provided for this purpose. That is, a plurality of polishing liquid supply systems are provided.

In this polishing apparatus, two kinds of polishing liquids 12a and 12b can be supplied at the same time, and the polishing liquids 12a and 12b can be switched during processing, so that excellent polishing can be performed. . If pure water is supplied to one of the polishing liquid supply passages, for example, the polishing liquid supply passage 11b, the concentration of the polishing liquid 12a can be controlled during processing.

FIG. 3 is a schematic view showing a part of another polishing apparatus according to the present invention. As shown in the figure, the rotary shaft 13
A rotary platen 15 made of porous ceramics and having a thickness of 5 mm is attached to the rotary platen 15, and a polishing pad 17 is attached to the rotary platen 15.
Is attached, and a static pressure floating pad 16 that moves in conjunction with the rotary holder 4 is provided below the rotary platen 15.

Next, a method of polishing a semiconductor wafer with the polishing apparatus shown in FIG. 3 will be described. First, the rotating platen 1 is operated by operating the motor 9.
5. The polishing pad 17 is rotated, and the semiconductor wafer 3 is pressed against the polishing pad 17 while being rotated by the rotation holder 4.
Moreover, if the polishing liquid 12 is supplied to the static pressure floating pad 16,
The polishing liquid 12 passes through the holes of the rotary platen 15 and further passes through many cavities inside the polishing pad 17, reaches the polishing surface of the polishing pad 17, and the surface of the semiconductor wafer 3 is polished. To be done. In this case, the rolling load of the rotary holder 4 and the lifting load of the rotary platen 15 by the static pressure floating pad 16 are set to be the same.

In this polishing apparatus and polishing method, since no thrust load is applied to the rotary platen 15,
Since the thickness of the rotary platen 15 can be reduced, the polishing liquid 12 can be easily supplied. Further, since it is sufficient to supply the polishing liquid 12 only to the portion where the semiconductor wafer 3 is in contact with the polishing pad 17, the amount of the expensive polishing liquid 12 used is 1/10 of that of the polishing processing apparatus shown in FIG. Since it can be extremely reduced, the polishing processing cost can be reduced. Further, when the polishing pad 17 is exhausted, the polishing pad 17 can be replaced together with the rotary platen 15 for more automation.

Although the polishing pad 17 having water permeability is used in the present invention, the polishing pad 17 can be manufactured by the following method. That is, the conventional polishing pad 17
By impregnating a cloth with a polymer resin such as polyurethane or foaming the polyurethane resin to form a cavity, fine irregularities necessary for polishing are formed on the polishing surface of the polishing pad 17. In order to obtain the water permeability necessary for the present invention, in the final manufacturing step of these conventional polishing pads 17, many through-hole fine holes are processed by mechanical processing such as laser beam irradiation or chemical treatment such as etching. Can be achieved. It can also be manufactured by a method in which a large number of air-core fine fibers are bundled, impregnated with a resin, and then sliced.

In the above embodiments, the case where the work piece is the semiconductor wafer 3 has been described, but the present invention can be applied to the case where the work piece is a metal plate, a ceramic plate or the like. Further, in the above-described embodiment, the rotary platens 10 and 15 are made of porous ceramics, but the rotary platens may be made of another porous material such as a honeycomb structure.

[0030]

As described above, in the polishing apparatus and the polishing method according to the present invention, the fine recesses on the polishing surface of the polishing pad are clogged with the polishing powder of the semiconductor wafer or the slurry solid in the polishing liquid. Can be prevented,
Since the processing efficiency does not decrease, the productivity is good, and it is not necessary to carry out the conditioning work for each processing, and since it is not necessary to replace and replace the polishing pad every day, the running cost is low.

Further, when the polishing pad is attached on a rotary platen made of a porous material and the polishing liquid is supplied to the polishing pad from the rotary platen, the temperature of the polishing liquid is set to a predetermined condition. By supplying, the rotating platen can be brought to a predetermined temperature, and stable polishing can be performed.

When the rotary platen made of porous ceramics is used, the rotary platen can be easily manufactured, so that the manufacturing cost is low.

Further, when a plurality of polishing liquid supply systems are provided, the polishing liquid can be switched during the polishing process, so that excellent polishing process can be performed.

Further, when the polishing pad is attached to the rotary platen made of a porous material and the static pressure floating pad is provided on the back surface of the rotary platen, the thickness of the rotary platen can be reduced. Therefore, the polishing liquid can be easily supplied.

Further, the polishing pad is attached on a rotary surface plate made of a porous material, a static pressure floating pad is provided on the back surface of the rotary surface plate, and the polishing liquid is supplied from the static pressure floating pad to the rotary surface plate. When the polishing is performed while compensating the pressing force of the workpiece against the polishing pad, the amount of the polishing liquid used can be reduced, so that the polishing cost can be reduced.

As described above, the effect of the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is a sectional view showing a part of a polishing apparatus according to the present invention.

FIG. 2 is a schematic partial sectional view showing a part of another polishing apparatus according to the present invention.

FIG. 3 is a schematic view showing a part of another polishing apparatus according to the present invention.

FIG. 4 is a schematic view showing a conventional chemical mechanical polishing apparatus.

5 is a detailed cross-sectional view showing a part of the chemical mechanical polishing apparatus shown in FIG.

[Explanation of symbols]

 3 ... Semiconductor wafer 10 ... Rotating surface plate 11a, 11b ... Polishing liquid supply path 14a, 14b ... Rotating shaft seal 15 ... Rotating surface plate 16 ... Static pressure floating pad 17 ... Polishing pad

Front page continued (72) Inventor Kenji Furusawa 1-280, Higashi Koikekubo, Kokubunji, Tokyo, Hitachi Central Research Laboratory (72) Inventor Masayuki Nagasawa 1-280, Higashi Koikeku, Tokyo Kokubunji City Central Research Laboratory, Hitachi, Ltd.

Claims (7)

[Claims] 1. A polishing apparatus for performing relative motion while pressing a workpiece on a polishing surface of a polishing pad, wherein a polishing pad having water permeability is used, and the polishing pad is polished from the back surface of the polishing pad. A polishing apparatus that performs polishing while supplying a polishing liquid to the surface. 2. The polishing pad is attached to a rotary platen made of a porous material, and the polishing liquid is supplied to the polishing pad from inside the rotary platen.
Polishing device 3. The polishing apparatus according to claim 2, wherein the rotating platen made of porous ceramics is used. 4. The polishing apparatus according to claim 1, wherein a plurality of polishing liquid supply systems are provided. 5. The polishing according to claim 1, wherein the polishing pad is attached on a rotary platen made of a porous material, and a static pressure floating pad is provided on the back surface of the rotary platen. Processing equipment. 6. A polishing method in which a workpiece is pressed against the polishing surface of a polishing pad to cause relative motion, and a polishing pad having water permeability is used, and the polishing pad is polished from the back surface of the polishing pad. A polishing method, wherein the polishing is performed while supplying a polishing liquid to the surface. 7. The polishing pad is attached on a rotary platen made of a porous material, a static pressure floating pad is provided on the back surface of the rotary platen, and the polishing liquid is rotated from the static pressure floating pad. 7. The polishing method according to claim 6, wherein the polishing is performed while supplying the surface plate and compensating the pressing force of the workpiece against the polishing pad.