JP2001232557A - Device and method for polishing both faces of workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for polishing both faces of a workpiece capable of manufacturing such a workpiece that allows a surface and a rear surface to be distinguished easily by easily controlling luster of one polishing face of the workpiece without reducing a polishing rate for the workpiece. SOLUTION: This both face polishing device for a semiconductor wafer has an upper surface plate 3 and a lower surface plate 5 provided with polishing cloths 2, 4, a disc-shaped carrier 6 which is arranged between both surface plates 3 and 5 and in which a storage hole 9 storing the workpiece W whose both faces are polished is provided and a driven gear part 10 is formed in an outer fringe part, and a sun gear 7 and an internal gear 8 meshing with the gear part 10 of the carrier 6 to make the carrier 6 perform planetary movement. Furthermore, it has an abrasive supply device 11 supplying abrasive S from a polishing face Wa on one side of the workpiece W and a polishing inhibitor supply device 12 supplying polishing inhibitor A to a polishing face Wb on the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-side polishing apparatus for polishing a work such as a semiconductor wafer and a double-side polishing method using the same. In particular, the present invention relates to a method for uniformly polishing both polishing surfaces of a work such as a semiconductor wafer. The present invention relates to a double-side polishing apparatus and a double-side polishing method for producing a difference in polishing amount between polishing surfaces.

[0002]

2. Description of the Related Art To manufacture a semiconductor wafer, for example, a silicon wafer, a single-crystal semiconductor ingot is made from polycrystalline silicon by, for example, the Czochralski method, and the ingot is sliced to a predetermined thickness by a multi-wire saw or the like. Manufacture semiconductor wafers.

[0003] Alumina abrasive grains or the like are used to remove the uneven saw mark present on the surface of the silicon wafer and to smooth it, and to make the depth of processing strain uniform and the thickness within and between the wafers uniform. In the mirror polishing step using the lapping and polishing liquid, the surface is processed into a smooth and non-distorted mirror surface.

A conventional mirror polishing process is disclosed in Japanese Patent Laid-Open No. 10-18 / 1998.
No. 0616, an upper surface plate 3 provided with an upper polishing cloth 32 using a double-side polishing apparatus 31 as shown in FIG.
3. Carrier 37 disposed between lower surface plate 35 provided with lower polishing cloth 34 and provided with silicon wafer storage hole 36
Containing a silicon wafer W1 in an alkaline solution, and calcined silica or colloidal silica dispersed in an alkaline solution S
To an abrasive supply device 38 provided above the upper platen 33.
From the upper surface plate 33, the lower surface plate 35 and the silicon wafer W1 housed in the carrier 37, and both sides of the semiconductor wafer W1 are chemically and mechanically polished by rotation and rubbing under pressure. There are no layers and no dirt.

On the other hand, the silicon wafer W1 to be polished
There is a demand for a wafer in which the upper limit of the back surface glossiness is determined depending on the purpose. In the polishing of the wafer having the upper limit of the back surface glossiness, the backside glossiness is controlled by the conventional double-side polishing apparatus 31 by the rotation speed condition and the injection of the surfactant A. In this case, in the polishing by the conventional double-side polishing apparatus 31, the polishing agent S supplied from the polishing agent supply device 38 is switched to the surfactant A by the electromagnetic switching valve 40 controlled by the computer 39 during the polishing process, and the silicon wafer is polished. Although the surfactant A is supplied to the polishing surface of W1, a large amount of the surfactant A is supplied to the upper platen 33 side.
As a result, the polishing amount on the upper surface plate 33 side of the silicon wafer, that is, the upper polishing surface Wa, is reduced, and a difference in the polishing amount is generated between the upper and lower polishing surfaces (front and back surfaces). The polishing of the silicon wafer W1 that can identify the front and back surfaces of the silicon wafer in degrees can be performed.

However, when the polishing process is continuously repeated,
As shown in FIG. 8, both polishing surfaces contain the same amount of surfactant A, and the etching function of the polishing agent S on the surface of the silicon wafer W1 decreases, and the polishing rate decreases. As shown in the third conventional method, a predetermined polishing amount cannot be obtained, and the effect of the surfactant is not exerted on the polishing surface on the lower platen 37 side, that is, the lower polishing surface, so that the lower polishing of the silicon wafer W1 is performed. The polishing amount of the surface (surface) exceeds a predetermined value, and the glossiness of the lower polishing surface often exceeds the upper limit as shown in the conventional method of FIG.

Therefore, by making it possible to easily control the gloss of one polished surface of the work without lowering the polishing rate for the work, it is possible to manufacture a work whose front and back surfaces can be easily identified. There has been a demand for a polishing apparatus and a double-side polishing method.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables the gloss of one polished surface of a work to be easily controlled without lowering the polishing rate for the work. Accordingly, an object of the present invention is to provide a double-side polishing apparatus and a double-side polishing method capable of manufacturing a work whose front and rear surfaces can be easily identified.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention of claim 1 of the present application is directed to an upper platen and a lower platen provided with a polishing pad, and disposed between the platens. A carrier provided with a storage hole for storing a workpiece to be polished, and having a disk-shaped outer peripheral portion and a driven gear portion formed thereon, and a sun gear that meshes with the gear portion of the carrier and causes the carrier to perform planetary motion. A double-side polishing apparatus having an internal gear, comprising: a polishing agent supply device that supplies a polishing agent from one polishing surface of a work; and a polishing inhibitor supply device that supplies a polishing inhibitor to the other polishing surface. The gist of the present invention is a double-side polishing apparatus.

[0010] In the invention of claim 2 of the present application, the abrasive supply device supplies the abrasive from the upper polishing surface of the work, and the polishing suppressor supply device supplies the polishing suppressor to the lower polishing surface of the work. The gist is a double-side polishing apparatus according to the first aspect.

According to a third aspect of the present invention, in the double-side polishing apparatus according to claim 2, the polishing inhibitor supplying apparatus supplies the polishing agent to a lower polishing surface of the work from a lower region of the sun gear. The gist is that

According to a fourth aspect of the present invention, in a double-side polishing method using a double-side polishing apparatus, after attaching a work to the double-side polishing apparatus, polishing is performed while supplying an abrasive to both surfaces of the work. The gist of the present invention is a double-sided polishing method characterized in that a polishing inhibitor is supplied to one surface of a work to generate a difference in the amount of polishing between both polishing surfaces of the work.

According to a fifth aspect of the present invention, there is provided the double-side polishing method according to the sixth aspect, wherein the supply of the polishing inhibitor to one surface of the work is a supply to the lower polishing surface of the work. The gist is that.

According to a sixth aspect of the present invention, there is provided a double-side polishing method according to the seventh aspect, wherein the supply of the work to the lower polishing surface is performed from a lower region of the sun gear. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a double-side polishing apparatus and a double-side polishing method using the same according to the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a double-side polishing apparatus 1 used for polishing a work, for example, a silicon wafer which is a semiconductor wafer, comprises an upper platen 3 provided with an upper polishing cloth 2, and an upper platen 3. A lower platen 5 provided with a lower polishing cloth 4 provided opposite to 3; a carrier 6 disposed between the upper and lower platens 3, 5; and a sun gear 7 for making the carrier 6 planetary. And an internal gear 8. A carrier, for example, a silicon wafer W
A storage hole 9 for storing the gear portion 1 is provided, and a driven gear portion 10 is formed in an outer edge portion in a disk shape.
0, the sun gear 7 and the internal gear 8 mesh with each other, so that the carrier 6 performs a planetary motion between the upper and lower polishing cloths 2 and 4, and the upper polishing surface (front surface) Wa and the lower polishing surface (back surface) Wb of the silicon wafer W. Is to be polished.

The double-side polishing apparatus 1 further includes an abrasive supply device 11 for supplying the abrasive S to the polishing surfaces Wa and Wb of the silicon wafer W, and a polishing inhibitor such as an interface, for example, on one surface of the polishing surface, for example, the lower polishing surface Wb. A polishing inhibitor supplying device 12 for supplying the activator A.

The abrasive supply device 11 includes a plurality of distribution paths 13 provided on the upper surface plate 3, a distribution pipe 14 communicating with the distribution path 13, and a distribution pipe 14 communicating with the distribution pipe 14 to distribute the abrasive S. And a distributor 15 for distributing the slurry to an abrasive supply pipe 16. The distributor 15 is connected to an abrasive supply pipe 16. Abrasive supply device (not shown)
Is communicated to.

As shown in FIGS. 1 and 2, the polishing-suppressing agent supply device 12 penetrates a gear rotation shaft 19 for rotating the sun gear 7, and a gear mounting portion 20 provided on the gear rotation shaft 19. A polishing inhibitor supply passage 22 provided with a supply port 21 which is formed in the lower region of the sun gear 7 and opens to the lower polishing surface Wb of the polishing surface.
As shown in FIG. 1, a polishing inhibitor supply device (not shown) through a polishing inhibitor supply electromagnetic opening / closing valve 24 controlled by a computer 17 via a polishing inhibitor supply pipe 22 and a coupling 23. Is communicated to.

The supply port 21 is provided in the lower region of the sun gear 7, for example, in the gear mounting portion 20 located on the lower surface of the sun gear 7. It may be provided.

The computer 17 is a computer 1
7, an upper platen driving device 25 provided to be able to rotate and raise and lower the upper platen 3, a sun gear driving device 26 for rotating the sun gear 7, and a lower platen 5 are rotated. The lower platen driving device 27 to be driven is controlled.

Next, a method for double-side polishing a silicon wafer using the double-side polishing apparatus 1 according to the present invention will be described.

When the silicon wafer W is mirror-polished on both sides, first, as shown in FIG. 1, the carrier 6 is placed on the lower polishing cloth 4 provided on the lower platen 5 while the gear portion of the carrier 6 is being polished. 10 is engaged with the sun gear 7 and the inner gear 8. Next, the silicon wafer W is inserted into the storage hole 9 of the carrier 6.
To be stored.

Thereafter, the upper platen driving device 25 is operated by the computer 17 containing the program to lower the upper platen 3, and the lower platen 5 provided with the lower polishing cloth 4 and the upper polishing cloth 2 are provided. After the carrier 6 is pressed and clamped between the upper stools 3, the computer 17 activates the abrasive supply electromagnetic opening / closing valve 18 to transfer the abrasive S from the abrasive supply device to the abrasive supply pipe 16, Polishing surface Wa of the silicon wafer W via the vessel 15, the distribution pipe 14 and the distribution path 13
To the lower polishing surface Wb.

Further, while the abrasive S is being supplied to both polishing surfaces Wa and Wb, the upper platen driving device 25 is operated by the computer 17 to operate the upper platen 3 and the sun gear driving device 26 so that the sun gear is driven. 7. The lower platen driving device 27 is operated to rotate the lower platen 5, thereby rotating the carrier 6 between the both platens 3 and 5 in a planetary manner. With the planetary rotation of the carrier 6, the semiconductor wafer W stored in the storage hole 9 of the carrier 6 repeats the rotation according to the revolution and rotation of the carrier 6, and the polishing liquid S and the two polishing cloths 2, 4 act to perform the silicon rotation. Both polished surfaces Wa and Wb of the wafer W are chemically and mechanically polished.

In the course of this polishing step, the computer 17 opens the electromagnetic opening / closing valve 24 for supplying the polishing suppressant based on the program, and as shown in FIG. Supplies the polishing inhibitor A to the lower polishing surface Wb of the silicon wafer W. Lower polishing surface Wb
When the polishing inhibitor A is supplied to the lower polishing surface Wb, the lower polishing surface Wb is in a state in which the polishing inhibitor A is contained more than the polishing agent S. As a result, the polishing amount of the lower polishing surface Wb of the silicon wafer is reduced, Gloss is suppressed.

Since the polishing inhibitor A is supplied to the lower polishing surface Wb from the supply port 21 located in the lower region of the sun gear 7, it is hardly supplied to the upper polishing surface Wa. Since the neutralizing action with S is suppressed, the polishing is continued, and the upper polished surface Wa is polished by a predetermined polishing amount to increase the gloss.

Therefore, by supplying the polishing agent S and the polishing inhibitor A having different effects on polishing from different positions, the polishing rate for the upper polishing surface (surface) Wa is secured (suppression of reduction), and the polishing is suppressed. Agent A has lower polishing surface (back surface) Wb
And the gloss of the lower polished surface Wb can be easily reduced (glossiness control), and the front and rear surfaces can be easily formed by the difference in gloss between the upper polished surface (front) Wa and the lower polished surface (back) Wb. Can be identified.

[0029]

EXAMPLE (Test 1) TSC-1 (polyoxyethylene alkyl phenyl ether) was used as a surfactant by using a silicon wafer having a diameter of 8 inches as a work using a double-side polishing apparatus according to the present invention as shown in FIG. Then, both sides were polished, and the polishing rate of the upper polished surface and the over-gloss ratio of the lower polished surface were examined and compared with the conventional example.

FIG. 3 shows the test results of the polishing rate of the upper polishing surface.
Shown in Result: As can be seen from FIG. 3, the polishing rate of the example was 0.36 μm / min and that of the conventional example was 0.27 μm / min.
It was found to show a value about 33% larger than that of.

FIG. 4 shows the test result of the gloss over rate of the lower polished surface. Result: As can be seen from FIG. 4, the gloss over-rate of the example was 0.01%, which was drastically reduced to 1/25 as compared with 0.25% of the conventional example.

(Test 2) The relationship between the polishing amount of the lower polished surface and the flatness STIR and the relationship between the polishing amount of the lower polished surface and the glossiness were examined in the same manner as in the above Test 1. However,
The angle of incidence of the gloss meter is 20 degrees.

FIG. 5 shows the relationship between the polishing amount of the lower polishing surface and the flatness STIR. Result: As can be seen from FIG. 5, the flatness improves with the polishing amount, and becomes almost constant when the polishing amount is 4 μmm or more.

FIG. 6 shows the relationship between the polishing amount of the lower polishing surface and the glossiness.
Shown in Result: As can be seen from FIG. 6, the glossiness increases with the polishing amount, and the surface becomes a mirror surface with the polishing amount of about 4 μm.

From the above test results, it has been found that in order to polish the silicon wafer to a high flatness and to polish the lower polishing surface to a non-mirror surface, the polishing amount must be 4 μm or less. Also, to clearly identify the upper and lower polishing surfaces,
It has been found that it is preferable to make the polishing amount of the lower polishing surface smaller than 1.5 μm.

[0036]

According to the double-side polishing apparatus and the polishing method of the present invention, when it is necessary to control the gloss of the back surface of the wafer, the gloss of one polished surface of the work can be easily reduced without lowering the polishing rate for the work. Thus, it is possible to provide a double-side polishing apparatus and a double-side polishing method capable of manufacturing a work whose front and back surfaces can be easily identified.

That is, since there is provided a polishing agent supply device for supplying a polishing agent from one polishing surface of the semiconductor wafer and a polishing inhibitor supply device for supplying a polishing inhibitor to the other polishing surface of the polishing surface, By supplying a polishing agent and a polishing inhibitor that act differently from different positions, the polishing rate for the front surface of the work is secured, the polishing inhibitor is sufficiently distributed on the back surface, and the gloss on the back surface is easily reduced. The front surface and the back surface can be easily identified based on the difference in gloss between the front surface and the back surface of the work.

Further, the polishing agent supply device supplies the polishing agent from the upper polishing surface of the work, and the polishing suppressor supply device supplies the polishing inhibitor to the lower polishing surface of the work.
Almost no polishing inhibitor is supplied to the upper polishing surface (surface), and the neutralizing action with the polishing agent is suppressed. Therefore, the surface is continuously polished, the surface is polished to a predetermined polishing amount, the gloss increases, and the lower polishing surface is increased. The polishing inhibitor is sufficiently distributed on the (back surface), the gloss of the back surface can be easily reduced, and the front surface and the back surface can be easily distinguished by the difference in gloss between the front surface and the back surface.

Further, since the polishing inhibitor supplying device supplies the polishing agent to the lower polishing surface of the work from the lower region of the sun gear, almost no polishing inhibitor is supplied to the upper polishing surface, and the surface is polished to a predetermined level. It is polished to increase the gloss, the backside is sufficiently spread with the polishing inhibitor, the gloss of the backside can be easily reduced, and the difference between the gloss of the front side and the backside can be easily distinguished from the front side. Things.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a double-side polishing apparatus according to the present invention.

FIG. 2 is a schematic view of a polishing step using a double-side polishing apparatus according to the present invention.

FIG. 3 is a view showing test results of a polishing rate of an upper polished surface using an example.

FIG. 4 is a view showing a test result of an over gloss ratio of a lower polished surface using an example.

FIG. 5 shows the polishing amount and flatness STI of the lower polished surface using the example.
The figure which shows the relationship of R.

FIG. 6 is a diagram illustrating a relationship between a polishing amount and a glossiness of a lower polishing surface using an example.

FIG. 7 is an explanatory view of a conventional double-side polishing manufacturing apparatus.

FIG. 8 is a schematic view of a polishing step using a conventional double-side polishing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 double-side polishing device 2 upper polishing cloth 3 upper polishing plate 4 lower polishing cloth 5 lower polishing plate 6 carrier 7 sun gear 8 internal gear 9 storage hole 10 gear portion 11 abrasive supply device 12 polishing inhibitor supply device 13 distribution path 14 minute pipe REFERENCE SIGNS LIST 15 Distributor 16 Abrasive supply pipe 17 Computer 18 Electromagnetic on-off valve for supplying abrasive 19 Gear rotating shaft 20 Gear mounting portion 21 Supply port 22 Polishing inhibitor supply passage 23 Coupling A Polishing inhibitor S Abrasive

Claims (6)

[Claims] 1. An upper surface plate and a lower surface plate provided with a polishing cloth, and a storage hole for storing a work to be polished on both sides, which is disposed between the upper and lower surface plates, and a disk-shaped outer edge portion. In a double-side polishing apparatus having a carrier in which a driven gear portion is formed, a sun gear that meshes with the gear portion of the carrier, and causes the carrier to planetary move, an abrasive is supplied from one polishing surface of the work. A polishing agent supply device for supplying a polishing inhibitor to the other polishing surface. 2. The polishing apparatus according to claim 1, wherein the polishing agent supply device supplies the polishing agent from an upper polishing surface of the work, and the polishing inhibitor supplying device supplies the polishing inhibitor to the lower polishing surface of the work. A double-side polishing apparatus according to item 1. 3. The double-side polishing apparatus according to claim 2, wherein the polishing agent supplying apparatus supplies the polishing agent to a lower polishing surface of the work from a lower region of the sun gear. 4. In a double-side polishing method using a double-side polishing apparatus, after attaching a work to the double-side polishing apparatus, polishing is performed while supplying an abrasive to both sides of the work, and polishing is performed on one side of the work during the polishing process. A double-sided polishing method comprising supplying an inhibitor and causing a difference in a polishing amount between both polishing surfaces of a work. 5. The double-side polishing method according to claim 4, wherein the supply of the polishing inhibitor to one surface of the work is a supply to a lower polishing surface of the work. 6. The double-side polishing method according to claim 5, wherein the supply of the work to the lower polishing surface is performed from a lower region of a sun gear.