JPH09277159A - Polishing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing method and a device thereof which can conduct even processes including final polishing with a single surface plate and attain the compactness of a machine effectively. SOLUTION: With polishing cloth 10 between an object W to be polished held at a retaining device 5 and a surface plate 4, the surface Wa of the object W to be polished is polished to form a flat surface contour. This method involves the first polishing process for conducting polishing with hard polishing cloth 12 provided at the surface plate 4, and the second polishing process for conducting final polishing with soft polishing cloth 11 provided at the surface plate 4. It is thus possible to conduct main polishing and final polishing efficiently and properly with only one surface plate 4 for attainment of machine compactness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and apparatus for polishing materials such as semiconductor substrates (wafers) and quartz substrates used for manufacturing semiconductor devices.

[0002]

2. Description of the Related Art For example, FIGS. 12 to 14 show a configuration example of a conventional substrate polishing apparatus 100 of this type. This substrate polishing apparatus 100 includes a wafer loader 101,
A wafer unloader 102, a main polishing surface plate 103, a finishing surface plate 104, and a holder 105 for holding the semiconductor wafer W are provided.

The main polishing platen 103 has a polishing cloth made of urethane foam or a hard non-woven cloth, or a soft non-woven cloth under the urethane foam polishing cloth 106a, in order to improve the polishing speed and polishing uniformity. A polishing cloth 106 (see FIG. 14) having a two-layer structure formed by laying 106b is used.
A polishing cloth 107 made of a soft non-woven fabric or the like is used for the finish polishing surface plate 104. Each surface plate 1
03, 104 are provided with liquid supply parts 108a, 108b such as abrasive grains or pure water.
The polishing is performed while flowing the liquid from 08a and 108b.

The holder 105 holds the semiconductor wafer W with the surface to be polished facing downward. Then, the semiconductor wafer W is transferred to the polishing cloths 106 and 107 by the holder 105. When performing general polishing, the semiconductor wafer W is conveyed to the main polishing surface plate 103 by the holder 105 as shown in FIG. 15, and the semiconductor wafer W is moved by the polishing cloth 106 on the main polishing surface plate 103. The surface of is mainly polished (see FIG. 13). In this case, the wafer holder 105 rotationally drives the semiconductor wafer W, and the liquid supply unit 108.
From a, polishing is performed while dropping abrasive grains.

After the main polishing is finished, a large amount of abrasive grains and polishing dust adhere to the surface to be polished of the semiconductor wafer W, and a large number of small scratches are easily attached. Therefore, next, as shown in FIG. 16, the semiconductor wafer W is conveyed to the finish polishing surface plate 104 by the holder 105, and the semiconductor wafer W is finish-polished by the soft polishing cloth 107 to remove the abrasive grains and scratches. In this case, the finish polishing surface plate 104 is also rotating similarly to the main polishing surface plate 103, and the finish polishing is performed while dropping the liquid from the liquid supply portion 49b.

In order to further improve such a polishing method, for example, according to Japanese Patent Laid-Open No. 6-208980, a hard polishing cloth 110 is provided with a large number of holes 11 as shown in FIG.
0a is drilled and a soft polishing cloth 1 is provided in each hole 110a.
A polishing cloth 109 in which 11 is embedded is used. According to this method, scratches and the like are removed by the soft polishing cloth 111. In addition, in FIG. 17, the semiconductor wafer W is held by a holder 105 ′, and
The surface of the semiconductor wafer W is polished on 03 '.

[0007]

However, in the conventional polishing apparatus as described above, two polishing plates, that is, the main polishing polishing plate 103 and the finish polishing polishing plate 104, are used to polish the semiconductor wafer W. I have it. For this reason, the polishing apparatus becomes large and bulky, and the area occupied by the apparatus at the semiconductor device manufacturing site must be increased. Also,
As described above, the semiconductor wafer W is transported between the main polishing surface plate 103 and the final polishing surface plate 104 by the end of polishing, so that the throughput is increased. Further, as for the polishing cloth, it is necessary to prepare two kinds of polishing cloths, which causes a problem that the polishing cost increases.

Further, in the polishing method according to the above-mentioned Japanese Patent Laid-Open No. 6-208980, the semiconductor wafer W always comes into contact with the hard polishing cloth 110 during polishing, so that the surface of the semiconductor wafer W is not scratched. Occurs. Also, 1
Since it is not possible to perform the final polishing only with the surface plate 103 'of the table, a surface plate for the final polishing is required, and in this case, too, there is a problem in that the size of the apparatus is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing method and an apparatus which can perform final polishing with a single platen and at the same time effectively realize compactness of the apparatus.

[0010]

According to the polishing method of the present invention, the surface of the object to be polished is polished by interposing a polishing cloth between the object to be polished held by the holder and the surface plate. A polishing method for forming a flat surface shape, comprising a first polishing step of polishing with a hard polishing cloth provided on the surface plate, and a soft surface provided on the surface plate after the first step. It has a second polishing step of performing final polishing with a polishing cloth.

Further, the polishing apparatus of the present invention polishes the holder for holding the object to be polished, the surface plate provided so as to face the holder, and the object to be polished provided on the surface plate. And a polishing cloth for polishing the polishing cloth. The polishing cloth is composed of a plurality of polishing cloths having different properties arranged at least in the central portion and the outer peripheral portion thereof.

Alternatively, in the polishing apparatus of the present invention, a holder for holding an object to be polished, a surface plate provided so as to face the holder, and the object to be polished provided on the surface plate are polished. A polishing cloth for, which is a polishing device, wherein the polishing cloth, a soft polishing cloth arranged in the center, and a hard polishing cloth arranged along the outer periphery of the soft polishing cloth, Composed.

Further, in the polishing apparatus of the present invention, a laminated polishing cloth composed of a hard polishing cloth and a soft polishing cloth is provided along the outer periphery of the soft polishing cloth.

The polishing apparatus of the present invention further comprises a polishing cloth in which hard polishing cloths and soft polishing cloths are alternately arranged along the outer periphery of the soft polishing cloth.

[0015]

The polishing apparatus of the present invention comprises one surface plate, one piece of polishing cloth composed of a soft polishing cloth and a hard polishing cloth, and a holder for holding a material to be polished, which is installed on the surface plate. In the polishing method of the present invention using this polishing apparatus, first, a semiconductor wafer is transferred to an outer hard polishing cloth arranged on one surface plate, and the semiconductor wafer is polished by this hard polishing cloth. After the main polishing with this hard polishing cloth, the semiconductor wafer is transferred to the soft polishing cloth in the central portion, and the final polishing is performed with this soft polishing cloth.

[0016]

According to the present invention, by arranging the hard polishing cloth and the soft polishing cloth on one surface plate in this way, it is possible to perform the main polishing to the final polishing of the semiconductor wafer with one surface plate. You can That is, an effect substantially equivalent to that of the polishing apparatus having the main polishing platen and the finish polishing platen separately is obtained. Therefore, the area occupied by the device in the factory is reduced, and the required amount of polishing cloth can be reduced from two to one, so that the manufacturing cost of the semiconductor device can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a substrate polishing method and apparatus according to the present invention will be described below with reference to FIGS. 1 and 2 show a configuration example of the polishing apparatus 1 in this embodiment. This substrate polishing apparatus 1 is
As shown in the figure, the wafer loader 2, the wafer unloader 3, the surface plate 4, the holder 5 for holding the semiconductor wafer W, and the polishing liquid supply nozzle 6 are provided. The polishing cloth 10 according to the present embodiment is installed on the surface plate 4.

The holder 5 conveys the semiconductor wafer W to the surface plate 4, and the surface Wa to be polished of the semiconductor wafer W is the polishing cloth 1.
The semiconductor wafer W is held so as to face the 0 side. The holding tool 5 can rotate the held semiconductor wafer W, and the surface plate 4 is also rotatable. For example, the holder 5 holds the semiconductor wafer W and rotates it in the direction of arrow A, and the surface plate 4 is rotatable in the direction of arrow B (FIG. 2).

Here, when the surface plate 4 has a diameter of, for example, about 90 cm, the polishing cloth 10 has a soft polishing cloth 11 formed of a circular non-woven fabric or urethane having a diameter of about 30 cm as shown in FIG. This soft polishing cloth 11 is constituted by a urethane foam hard polishing cloth 12 having a width of about 30 cm, which is provided outside the concentric circles. Further, as shown in FIG. 4, a hard polishing cloth 14 and a soft polishing cloth 15 may be laminated on the outer side of the concentric circle of the soft polishing cloth 11 to provide the polishing cloth 13 having a laminated structure. In addition, these soft polishing cloths 11
The ratio to the hard polishing cloth 12 or the polishing cloth 13 is not limited to this.

In this embodiment, a plurality of polishing liquid supply nozzles 6 are provided so that a plurality of liquids such as a polishing liquid, a chemical liquid and pure water used for polishing can be supplied. In this example, FIG.
Two polishing liquid supply nozzles 6a, 6 as shown in FIG.
b is installed at two locations, that is, directly above the center of the surface plate 4 and immediately above the boundary between the soft polishing cloth 11 and the hard polishing cloth 12.

Next, the polishing apparatus 1 configured as described above
In, an example of a method for polishing the semiconductor wafer W will be described. First, when main polishing is performed, the semiconductor wafer W is transported from the wafer loader 2 to the polishing cloth 12 on the surface plate 4 by the holder 5 as shown in FIG. Then, polishing is performed while dropping a predetermined polishing liquid from the polishing liquid supply nozzle 6b. At this time, the semiconductor wafer W is rotated by the holder 5 and the surface plate 4 is also rotated (FIG. 5 (B)).

Since a large amount of abrasive grains are attached to the surface of the semiconductor wafer W after the main polishing with the hard polishing cloth 12 is completed, foreign matter may not be completely removed by the cleaning in the next step as it is. Further, if a large number of scratches are generated, it may cause defects in the manufactured semiconductor device.

Therefore, the semiconductor wafer W is further transported by the holder 5 to the polishing cloth 11 on the surface plate 4 as shown in FIG. In this case, the final polishing is performed while dropping a predetermined polishing liquid (pure water, chemical liquid such as alkali) from the polishing liquid supply nozzle 6a. By this finish polishing, foreign matters and scratches attached to the surface of the semiconductor wafer W can be eliminated. The semiconductor wafer W that has been finish-polished is then transported to the unloader 3 by the holder 5.

The polishing of the semiconductor wafer W is completed by the above steps. By performing the polishing with the polishing apparatus 1 as described above, it is possible to obtain a flat and uniform polished surface without scratches and the like. In this case, the polishing apparatus 1 is provided with only a single surface plate 4, so that not only the required number of surface plates can be reduced to one, but also the area occupied by the polishing apparatus 1 in the factory can be reduced. it can. Also, surface plate 4
Since the number of polishing pads is reduced to one, the number of polishing cloths 10 required for polishing can be reduced to half, so that the process cost can be remarkably facilitated.

Next, a second embodiment of the present invention will be described. FIG. 7 shows a configuration example of the polishing pad 20 in this embodiment. The structure of the polishing apparatus 1 is substantially the same as that of the first embodiment described above, and thus detailed description thereof will be omitted.

In the polishing cloth 20 of the second embodiment, when the surface plate 4 has a diameter of, for example, about 60 cm, as shown in FIG. The outer peripheral portion is cut out to a thickness of about half the radius of 1/2. A hard polishing cloth 23 is attached to the hollowed-out portion to form a polishing cloth 22, that is, the polishing cloth 22 has a laminated structure in which the outer peripheral portion of the soft polishing cloth 21 and the hard polishing cloth 23 are bonded together.

In the second embodiment, the semiconductor wafer W
In the case of performing the main polishing of, the semiconductor wafer W is transported to the polishing cloth 22 on the surface plate 4 by the holder 5. Then, similarly to the above-described first embodiment, polishing is performed while dropping a predetermined polishing liquid from the polishing liquid supply nozzle 6b. In this case, by forming the upper layer portion of the polishing cloth 22 by the hard polishing cloth 23 and the lower layer portion by the soft polishing cloth 21, respectively, the hard polishing cloth 23 improves the uniformity in the chip and the soft polishing cloth 21 The uniformity within the semiconductor wafer W can be improved.

After the main polishing with the hard polishing cloth 22 is completed, the semiconductor wafer W is further conveyed to the polishing cloth 21 installed at the center of the fixed platen 4. By the final polishing with the polishing cloth 21, it is possible to eliminate foreign matters and scratches attached to the surface of the semiconductor wafer W. Also in the second embodiment, only one plate is required, and the area occupied by the polishing apparatus 1 in the factory can be reduced. Also, surface plate 4
Since the number of polishing pads 20 is reduced to one, the number of polishing cloths 20 required for polishing can be reduced to half, so that the process cost can be remarkably facilitated.

In the polishing cloth 20, especially the polishing cloth 22
However, an example in which the soft polishing cloth 21 and the hard polishing cloth 23 have a two-layer structure has been described, but a laminated structure of three or more layers may be used if necessary.

Next, a third embodiment of the present invention will be described. FIG. 8 and FIG. 9 show an example of the main part configuration in this embodiment. The configuration of the polishing apparatus 1 is substantially the same as that of the first and second embodiments described above, and thus detailed description thereof will be omitted.

In the polishing cloth 30 according to the third embodiment, the soft polishing cloth 3 is provided so as to substantially correspond to the central portion of the surface plate 4.
1 is arranged, and a hard polishing cloth 32 is arranged outside the soft polishing cloth 31. In this example, the soft polishing cloth 3
1 is formed in a shape with sharp corners as shown, that is, a star shape, for example. The tip of the soft polishing cloth 31 extends to the edge of the surface plate 4. The hard polishing cloth 32 is formed to have a circular outer periphery so as to fill the space between the hard polishing cloth 32 and the pointed portion of the soft polishing cloth 31.

Also in this third embodiment, two polishing liquid supply nozzles 6a and 6b are provided, that is, the polishing liquid supply nozzle 6a is near the center of the surface plate 4, and the polishing liquid supply nozzle 6b is fixed. They are arranged in the center of the board 4 and in the vicinity of an intermediate position between the edges thereof.

In the above case, in the hard polishing cloth 32, as in the first embodiment (see FIG. 4), a soft polishing cloth is provided as the lower layer, that is, a polishing cloth having a laminated structure of a hard polishing cloth and a soft polishing cloth. May be used.

Next, an example of a method for polishing the semiconductor wafer W in the polishing apparatus 1 according to the third embodiment will be described. First, when performing main polishing, as shown in FIG. 10, the semiconductor wafer W is transported from the wafer loader 2 to the polishing cloth 30 on the surface plate 4 by the holder 5. In this case, it is assumed that the soft polishing cloth 31 and the hard polishing cloth 32 are conveyed to a region alternately arranged along the circumference. Then, polishing is performed while dropping a predetermined polishing liquid from the polishing liquid supply nozzle 6b. At this time, the semiconductor wafer W is rotated by the holder 5 and the surface plate 4 is also rotated.

When the semiconductor wafer W is rotated, the semiconductor wafer W is alternately polished by the soft polishing cloth 31 and the hard polishing cloth 32. Therefore, the effect of improving the uniformity in the chip by the hard polishing cloth 32 and the softness It is possible to achieve both the effect of improving the uniformity within the wafer by the polishing cloth 31.

Since a large amount of abrasive grains are attached to the surface of the semiconductor wafer W after the main polishing is completed, the foreign matter may not be completely removed by the cleaning in the next step as it is. Also,
If many scratches occur, it may cause defects in the manufactured semiconductor device.

Then, the semiconductor wafer W is further transported by the holder 5 to the polishing cloth 31 located around the central portion of the surface plate 4 as shown in FIG. In this case, the final polishing is performed while dropping a predetermined polishing liquid (pure water, chemical liquid such as alkali) from the polishing liquid supply nozzle 6a. By this finish polishing, foreign matters and scratches attached to the surface of the semiconductor wafer W can be eliminated. The semiconductor wafer W that has been finish-polished is then transported to the unloader 3 by the holder 5.

The polishing of the semiconductor wafer W is completed by the above steps. By performing the polishing with the polishing apparatus 1 as described above, it is possible to obtain a flat and uniform polished surface without scratches and the like. In this case, the polishing apparatus 1 is provided with only a single surface plate 4, so that not only the required number of surface plates can be reduced to one, but also the area occupied by the polishing apparatus 1 in the factory can be reduced. it can. Also, surface plate 4
Since the number of polishing pads is reduced to one, the number of polishing cloths 30 required for polishing can be reduced to half, so that the process cost can be remarkably facilitated.

Here, in the third embodiment, an example in which the star-shaped soft polishing cloth 31 constituting the polishing cloth 30 is used has been described, but the soft polishing cloth 31 and the hard polishing cloth 32 are alternately arranged on the semiconductor wafer W. The shape is not limited to the star shape in the illustrated example, and other shapes can be adopted as appropriate as long as they are in contact with each other.

In each of the above-described embodiments, an example in which urethane foam is used as the hard polishing cloth and nonwoven fabric is used as the soft polishing cloth has been described, but the hard polishing cloth or the soft polishing cloth may be formed of other materials. You can In addition to the semiconductor wafer, materials to be generally polished such as glass and metal may be used as the material to be polished. Further, in the present invention, an example in which a soft polishing cloth is used on the inner side of the polishing cloth and a hard polishing cloth is used on the outer side thereof has been described, but the positional relationship between the two is not limited to this case. For example,
A hard polishing cloth may be placed on the inside and a soft polishing cloth may be placed on the outside, and it can be appropriately selected as necessary.

[0041]

As described above, according to the present invention, 1
Since the main polishing to the final polishing can be performed collectively on the table of the table, the number of the table of the polishing device can be reduced to one, and the area occupied by the device in the factory of the polishing device can be reduced. Space saving can be effectively realized. Further, since the number of surface plates is reduced to one, the number of polishing cloths required for polishing can be reduced to half, so that the process cost can be reduced. As a result, there is an advantage that the manufacturing cost and the product cost can be substantially reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the polishing apparatus according to the first embodiment of the present invention.

FIG. 3 is a plan view and a side sectional view of the polishing cloth according to the first embodiment of the present invention.

FIG. 4 is a plan view and a side sectional view showing a modified example of the polishing cloth according to the first embodiment of the present invention.

5A and 5B are a plan view and a side sectional view showing the operation of the polishing apparatus according to the first embodiment of the present invention.

6A and 6B are a plan view and a side sectional view showing the operation of the polishing apparatus according to the first embodiment of the present invention.

FIG. 7 is a plan view and a side sectional view of a polishing cloth according to a second embodiment of the present invention.

FIG. 8 is a plan view of a polishing apparatus according to a third embodiment of the present invention.

FIG. 9 is a side view of a polishing apparatus according to a third embodiment of the present invention.

FIG. 10 is a plan view showing the operation of the polishing apparatus according to the third embodiment of the present invention.

FIG. 11 is a plan view showing the operation of the polishing apparatus according to the third embodiment of the present invention.

FIG. 12 is a plan view showing a configuration example of a conventional polishing apparatus.

FIG. 13 is a side view showing a configuration example of a conventional polishing apparatus.

FIG. 14 is a side sectional view of a polishing cloth according to a conventional polishing apparatus.

FIG. 15 is a plan view showing the operation of the conventional polishing apparatus.

FIG. 16 is a plan view showing the operation of the conventional polishing apparatus.

FIG. 17 is a side sectional view showing a modified example of the conventional polishing apparatus.

[Explanation of symbols]

 1 Polishing Device 2 Wafer Loader 3 Wafer Unloader 4 Surface Plate 5 Holder 6 Polishing Liquid Supply Nozzle 10, 20, 30 Polishing Cloth W Semiconductor Wafer

Claims (5)

[Claims] 1. A polishing method in which a polishing cloth is interposed between an object to be polished held by a holder and a surface plate to polish the surface of the object to be polished to form a flat surface shape. A first polishing step for polishing with a hard polishing cloth provided on the surface plate, and a second polishing for performing final polishing with a soft polishing cloth provided on the surface plate after the first step is completed. A polishing method comprising the steps of: 2. A holder for holding an object to be polished, a surface plate provided so as to face the holder, and a polishing cloth provided on the surface plate for polishing the object to be polished. A polishing apparatus provided with the polishing cloth, wherein the polishing cloth is composed of a plurality of polishing cloths having different properties arranged at least in a central portion and an outer peripheral portion thereof. 3. A holder for holding an object to be polished, a surface plate provided so as to face the holder, and a polishing cloth for polishing the object to be polished provided on the surface plate. A polishing apparatus provided with the polishing cloth, wherein the polishing cloth is composed of a soft polishing cloth arranged in a central portion and a hard polishing cloth arranged along an outer periphery of the soft polishing cloth. Polishing equipment. 4. The polishing apparatus according to claim 3, further comprising a laminated polishing cloth made of a hard polishing cloth and a soft polishing cloth, which is provided along the outer periphery of the soft polishing cloth. 5. The polishing apparatus according to claim 3, further comprising a polishing cloth in which hard polishing cloth and soft polishing cloth are alternately arranged along an outer circumference of the soft polishing cloth.