JPH081503A - Polishing device for wafer - Google Patents

Abstract

PURPOSE:To provide a polishing device for a wafer capable of performing preparation and polishing work in a short time and miniaturizing a device. CONSTITUTION:This device is provided with a ribbonlike polishing cloth 7 located along a given movement path 9, a roller like jig 6 moving the polishing cloth 7 along the movement path 9 at a given speed by rotation and also pressing the polishing cloth 7 to a wafer surface, and a susceptor 5 reciprocatingly moving the relative position between a wafer 4 and the jig 6 in a horizontal direction and also adjusting the interval between the wafer 4 surface and the jig 6 so as to be always constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus for polishing the surface of a semiconductor wafer with a polishing cloth to flatten the surface.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of devices and the increase in the number of wiring layers, a technique for flattening an interlayer insulating film has become indispensable. Then, CMP (Chemical Mem) for flattening by polishing with a polishing cloth or the like
The mechanical polish) device has been attracting attention as an effective technique for reducing steps.

FIG. 9 is a plan view of a conventional wafer polishing apparatus of this type, and FIG. 10 is a sectional view taken along line XX in FIG. In the figure, 1 is a polishing cloth, and 2 is a plurality of wafers pressed on the polishing cloth 1 by a susceptor 3 as shown in the figure. In the conventional wafer polishing apparatus as described above, each wafer 2 is mounted on the susceptor 3, and the susceptor 3 is driven by, for example, air pressure to press each wafer 2 onto the polishing cloth 1. Then, a polishing agent called a slurry is flown over the surface of each wafer 2 so that each wafer 2 revolves while revolving as shown by the arrows in FIG. 9, and the polishing cloth 1 is also rotated to polish the surface of each wafer 2. are doing.

[0004]

Since the conventional wafer polishing apparatus polishes the surface of the wafer 2 as described above, when the pattern on the wafer surface is rough, the concave portion 2a on the wafer surface and the polishing cloth 1 are used. 11 and are contacted with each other, and not only the convex portion 2b which originally needs to be polished but also the concave portion 2a as shown by a broken line in the figure are polished, so that it is difficult to eliminate the step and it takes a long time to polish. There was a problem.

Each time one batch is polished, the polishing cloth 1 is dressed, that is, dressed for 5 minutes.
When the batch processing is performed, there is a problem that the polishing cloth 1 has to be replaced, and that the work time required for preparation is long.

Further, since the polishing cloth 1 has a large area, it is necessary to increase the contact pressure, which causes a problem that the apparatus becomes large.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wafer polishing apparatus which can be prepared and polished in a short time and can be miniaturized. It is a thing.

[0008]

According to a first aspect of the present invention, there is provided a wafer polishing apparatus which comprises a ribbon-shaped polishing cloth arranged along a predetermined movement path and a predetermined speed for rotating the polishing cloth at a predetermined speed. A roller-shaped jig for moving the polishing cloth against the wafer surface while moving along the moving path, a horizontal movement means for horizontally reciprocating the relative position of the wafer and the jig, and the wafer surface and the jig. And an interval adjusting means for adjusting so that the interval is always constant.

A wafer polishing apparatus according to a second aspect of the present invention is the wafer polishing apparatus according to the first aspect, wherein the polishing cloth movement path is formed in an endless shape, and a polishing cloth retention portion is provided in the middle thereof. .

According to a third aspect of the present invention, in the wafer polishing apparatus according to the first aspect, the movement path of the polishing cloth is between a pair of rollers arranged so that each end of the polishing cloth can be wound. It was formed.

A wafer polishing apparatus according to a fourth aspect of the present invention is the wafer polishing apparatus according to the second or third aspect, wherein dressing means for dressing the polishing cloth is provided in the middle of the movement path of the polishing cloth.

According to a fifth aspect of the present invention, in a wafer polishing apparatus, a ribbon-shaped polishing cloth is arranged along a predetermined moving path, and the polishing cloth is moved to a moving path at a predetermined speed by rotating. A roller-shaped jig that moves along the wafer and presses the polishing cloth against the wafer surface, a horizontal movement unit that horizontally reciprocates the relative position of the wafer and the jig, and the distance between the wafer surface and the jig is always constant. It is provided with an interval adjusting means for adjusting so as to be constant and a pressing force measuring means for measuring a pressing force when the jig is pressed against the wafer surface.

According to a sixth aspect of the present invention, in the wafer polishing apparatus according to the fifth aspect, the polishing is judged to be completed when the pressing force is constantly measured.

Further, according to a seventh aspect of the present invention, in a wafer polishing apparatus, a ribbon-shaped polishing cloth is arranged along a predetermined moving path, and the polishing cloth is moved to a moving path at a predetermined speed by rotating. A roller-shaped jig that moves along the wafer and presses the polishing cloth against the wafer surface, a horizontal movement unit that horizontally reciprocates the relative position of the wafer and the jig, and the distance between the wafer surface and the jig is always constant. It is provided with a gap adjusting means for adjusting so as to be constant and a film thickness measuring means for measuring the film thickness on the wafer surface.

Further, according to an eighth aspect of the present invention, in a wafer polishing apparatus, a ribbon-shaped polishing cloth is arranged along a predetermined moving path, and the polishing cloth is moved to a moving path at a predetermined speed by rotating. A roller-shaped jig that moves along the wafer and presses the polishing cloth against the wafer surface, a horizontal movement unit that horizontally reciprocates the relative position of the wafer and the jig, and the distance between the wafer surface and the jig is always constant. It is provided with a space adjusting means for adjusting so as to be constant and a pattern arrangement storing means for storing the pattern arrangement on the wafer surface.

[0016]

According to the first aspect of the present invention, the roller-shaped jig of the wafer polishing apparatus moves the ribbon-shaped polishing cloth along the moving path by rotating and reciprocates in the horizontal direction by the horizontal moving means. Press on the surface of a moving wafer.

Further, the polishing cloth of the wafer polishing apparatus according to the second aspect of the present invention moves along an endless movement path.

Further, the polishing cloth of the wafer polishing apparatus according to the third aspect of the present invention moves along the moving path formed between the pair of rollers, and is sequentially wound on one of the rollers.

The dressing means of the wafer polishing apparatus according to claim 4 of the present invention sharpens the polishing cloth in the middle of the movement path.

The pressing force measuring means of the wafer polishing apparatus according to claim 5 of the present invention measures the pressing force when the roller-shaped jig is pressed against the wafer surface via the polishing cloth.

Further, in the wafer polishing apparatus according to the sixth aspect of the present invention, the polishing is judged to be completed when the pressing force is constantly measured by the pressing force measuring means.

Further, the film thickness measuring means of the wafer polishing apparatus according to claim 7 of the present invention measures the film thickness on the wafer surface during polishing.

Further, the pattern arrangement storing means of the wafer polishing apparatus according to claim 8 of the present invention stores the pattern arrangement on the wafer surface before the start of polishing.

[0024]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. 1 is a diagram showing a schematic configuration of a wafer polishing apparatus in Embodiment 1 of the present invention, and FIG. 2 is an enlarged view showing an enlarged relationship between a jig shown in FIG. 1 and a wafer surface.

In the figure, 4 is a wafer having concave portions 4a and convex portions 4b on its surface, and 5 is a susceptor as a horizontal moving means and a space adjusting means for mounting the wafer 4 on its upper side. It is configured such that it can reciprocate horizontally and can move vertically.
Reference numeral 6 denotes a jig formed into a roller shape having a diameter of 10 mm and a length of 10 mm, for example, and is arranged in a movement path described later.
7 is, for example, a polishing cloth formed in a ribbon shape having a width of 10 mm and a length of 10 m, 8a to 8h are guide rollers for guiding the polishing cloth 7 to form a predetermined moving path 9, and 10 is a guide roller of the moving path 9. A holding portion provided between 8a and 8h, which temporarily holds the polishing cloth 7 by meandering, 11 is a supply pipe for supplying the slurry 12 to the surface of the wafer 4.

Next, the operation of the wafer polishing apparatus according to the first embodiment having the above structure will be described. First, while moving the susceptor 5 in the horizontal direction, the wafer 4
The gap is adjusted by moving upward so that the gap between the surface of the jig and the jig 6 becomes a predetermined value. Next, while supplying the slurry 12 to the surface of the wafer 4 from the supply pipe 11, the jig 6
When the tool is rotated, the polishing cloth 7 moves the guide rollers 8a to 8h.
3A begins to move in the movement path 9 formed by the step 6 and the surface of the wafer 4 is rubbed by the pressing force of the jig 6.
As shown by the broken line, a part of the upper surface of the convex portion 4b of the wafer 4 is removed by polishing.

When a part of the upper surface of the convex portion 4b is removed by this polishing, the distance between the surface of the wafer 4 and the jig 6 is increased by the amount of the removed portion, so that the susceptor 5 is moved upward by that amount. Adjust the movement to return the interval to the specified value. Thereafter, by repeating this operation, as shown in FIG. 3 (B), the convex portion 4b is gradually removed by polishing and becomes lower, and the polishing operation ends when all the convex portions 4b are removed.

As described above, according to the first embodiment, the moving ribbon-shaped polishing cloth 7 is pressed against the surface of the wafer 4 which reciprocates in the horizontal direction while the roller-shaped jig 6 maintains a predetermined interval. However, since it is polished by rubbing,
Only the convex portion 4b is surely polished, the step is eliminated in a short time regardless of the density of the pattern on the surface of the wafer 4, and polishing with good uniformity can be performed.

Since the contact between the wafer 4 and the polishing cloth 7 is almost linear contact and the contact area is small, in order to obtain the pressure (about 300 g / cm ² ) applied between the wafer 4 and the polishing cloth 7 during polishing. Since the required driving pressure is small and the ribbon-shaped polishing cloth 7 is used, the apparatus can be downsized. Furthermore, since the retention part 9 is provided in the movement path 9 of the polishing cloth 7 and the length of the polishing cloth 7 is lengthened, the replacement frequency can be greatly reduced. Since only the specific convex portion 4b on the surface of the wafer 4 can be polished,
Workability can also be improved.

Example 2. In the first embodiment, as the horizontal moving means and the space adjusting means, the case where the susceptor 5 is reciprocally moved in the horizontal direction and is moved in the vertical direction has been described. However, the susceptor 5 is fixed and the jig 6 is used. The reciprocal movement in the horizontal direction and the vertical movement may be performed, and the same effect as that of the first embodiment can be obtained.

Example 3. FIG. 4 is a diagram showing a schematic configuration of a wafer polishing apparatus in Embodiment 3 of the present invention. In the figure, 13 is both guide rollers 8e and 8f of the moving path 9.
The dressing means is provided between the dressing means and for dressing the polishing cloth 7. The configuration other than that the dressing means 13 is provided is the same as that of the first embodiment shown in FIG. The dressing means 13 is configured to press the abrasive grain layer, in which diamond grains and the like are embedded, against the polishing cloth 7 while flowing cold water.

FIG. 5 is a characteristic diagram showing the relationship between the cumulative amount of polishing and the polishing rate when no dressing is performed. FIG. 5A shows the case of a thermal oxide film, and FIG. 5B shows the pattern. The case of the attached BPSG film is shown. From these characteristic diagrams, it is clear that the polishing rate decreases as the cumulative polishing amount increases in any case. The reason for this is that the irregularities on the surface of the polishing pad 7 become clogged, and it is well understood that dressing is an indispensable task.

As described above, according to the third embodiment, the polishing cloth 7 is applied by the dressing means 13 while polishing the wafer 4.
Since the polishing is performed, the polishing cloth 7 can always be polished in a state immediately after the polishing, so that stable polishing work can be performed without lowering the polishing rate, and workability can be improved. Further, since the polishing work and the dressing work can be performed independently of each other, it is possible to prevent dust and the like generated during the dressing work from adversely affecting the polishing work.

Embodiment 4 FIG. FIG. 6 is a view showing the schematic arrangement of a wafer polishing apparatus according to Embodiment 4 of the present invention. In the figure, the same parts as those in each of the above-described embodiments are designated by the same reference numerals and the description thereof is omitted. Reference numerals 14 and 15 denote a pair of rollers. One roller 14 stores the polishing cloth 7 in a predetermined length, and the other roller winds and collects the dressed polishing cloth 7.
Then, the polishing cloth 7 moves along the movement path 16 formed between the rollers 14 and 15.

As described above, according to the fourth embodiment, the movement path 16 of the polishing cloth 7 is formed between the pair of rollers 14 and 15, and the polishing cloth 7 accommodated in one roller 14 is moved along the movement path 16. Since it is pulled out and collected by the other roller 15 after polishing, the polishing cloth 7 can be lengthened with a simple configuration and the frequency of replacement can be reduced.

Example 5. In this fifth embodiment, although not shown, for example, the roller-shaped jig 6 of the polishing apparatus in the first embodiment shown in FIG. 1 is provided with a pressing force measuring means for measuring the pressing force applied during polishing. Now, as shown in FIG. 7A, when the polishing cloth 7 and the convex portion 4b of the wafer 4 are in contact with each other and the convex portion 4b is being polished, a force is exerted on the jig 6 and a pressing force is applied. The pressing force is measured by the measuring means. On the other hand, as shown in FIG. 7B, when passing through the concave portion 4a of the wafer 4, no force is applied to the jig 6, and the pressing force is not measured by the pressing force measuring means. Further, as shown in FIG. 7C, when all the convex portions 4b are removed by polishing, the entire surface of the wafer 4 is polished, so that the jig 6 is always subjected to a force, and the pressing force measuring means is used. The pressing force is constantly measured.

As described above, according to the fifth embodiment, since the pressing force applied to the jig 6 during polishing is measured by the pressing force measuring means, the pressing force of the wafer 4 is monitored by monitoring the pressing force. It becomes possible to grasp the surface condition, and
Since it can be determined that the polishing is completed while the jig 6 is constantly being pressed, it becomes easy to detect the polishing end point.

Example 6. FIG. 8 is a diagram showing a schematic configuration of a wafer polishing apparatus in Embodiment 6 of the present invention. In the figure, the same parts as those in each of the above-described embodiments are designated by the same reference numerals and the description thereof is omitted. Reference numeral 17 denotes an optical film thickness meter as a film thickness measuring means utilizing interference, and successively measures the film thickness on the surface of the wafer 4 along with each step of polishing the surface of the wafer 4.

As described above, in the sixth embodiment, the film thickness on the surface of the wafer 4 is successively measured by the optical film thickness meter 17 at each stage where the surface of the wafer 4 is polished. It is possible to monitor the film thickness of the polished portion in real time, and it becomes easy to detect the polishing end point.

Example 7. In the sixth embodiment, the case where the optical film thickness meter is used as the film thickness measuring means has been described, but the invention is not limited to this.
It is needless to say that a step meter that measures the step of the surface by raising a needle on the surface of the above can obtain the same effect as that of the sixth embodiment.

Example 8. In the eighth embodiment, although not shown, a pattern arrangement storage means for storing the pattern arrangement on the surface of the wafer is provided to store the pattern arrangement before the polishing is started. Only the part is polished.

As described above, according to the eighth embodiment, it is possible to selectively polish only the convex portions to be polished, based on the pattern arrangement information before the start of polishing stored in the pattern arrangement storage means. The time for polishing is shortened, workability can be improved, and unnecessary wear of the polishing cloth can be avoided, so that the life of the polishing cloth can be extended.

[0043]

As described above, according to the first aspect of the present invention, a ribbon-shaped polishing cloth arranged along a predetermined moving path, and the polishing cloth is moved to a moving path at a predetermined speed by rotating. A roller-shaped jig for moving along the wafer and pressing the polishing cloth against the surface of the wafer, and a horizontal direction moving means for horizontally reciprocating the relative position of the wafer and the jig,
To provide a wafer polishing apparatus capable of performing preparation and polishing work in a short time and downsizing, since the wafer is provided with a space adjusting means for adjusting so that the space between the wafer surface and the jig is always constant. You can

According to a second aspect of the present invention, in the first aspect, the movement path of the polishing cloth is formed in an endless shape, and a retaining portion for the polishing cloth is provided in the middle thereof. Not only the polishing work can be performed in a short time and downsizing, but also the polishing work can be shortened by changing the length of the polishing cloth to reduce the replacement frequency. A device can be provided.

According to a third aspect of the present invention, in the first aspect, the movement path of the polishing cloth is formed between the pair of rollers which are arranged so that each end of the polishing cloth can be wound. It is possible to perform the preparation and polishing work in a short time and to downsize the wafer, and further to shorten the preparation work time by lengthening the polishing cloth and reducing the replacement frequency. It is possible to provide the polishing apparatus.

According to claim 4 of the present invention, in claim 2 or 3, the dressing means for dressing the polishing cloth is provided in the middle of the movement path of the polishing cloth. It is possible to provide a wafer polishing apparatus capable of performing stable polishing work and improving workability, as well as being capable of performing the above-described process and downsizing.

According to a fifth aspect of the present invention, a ribbon-shaped polishing cloth arranged along a predetermined moving path, and the polishing cloth is moved along the moving path at a predetermined speed by rotating. Adjust the roller jig for pressing the polishing cloth against the wafer surface, the horizontal movement means for horizontally reciprocating the wafer and the relative position of the jig, and the distance between the wafer surface and the jig to be always constant. Since the gap adjusting means and the pressing force measuring means for measuring the pressing force when the jig is pressed against the wafer surface are provided, preparation, polishing and polishing work can be performed in a short time and the size can be reduced. Of course, it is possible to provide a wafer polishing apparatus in which the polishing endpoint can be easily detected.

According to the sixth aspect of the present invention, in the fifth aspect, it is determined that the polishing is completed when the pressing force is constantly measured. Therefore, the preparation and the polishing work are performed in a short time, and It is possible to provide a wafer polishing apparatus in which the end point of polishing can be detected more easily as well as being downsized.

Further, according to claim 7 of the present invention, a ribbon-shaped polishing cloth arranged along a predetermined moving path and the polishing cloth is moved along the moving path at a predetermined speed by rotating. A roller-shaped jig for pressing the polishing cloth against the wafer surface, a horizontal movement means for horizontally reciprocating the relative position of the wafer and the jig, and a gap between the wafer surface and the jig are always constant. Since the interval adjusting means for adjusting and the film thickness measuring means for measuring the film thickness on the wafer surface are provided, it goes without saying that the preparation and polishing operations can be performed in a short time and the size can be reduced. It is possible to provide a wafer polishing apparatus in which it is possible to easily detect the end point.

According to the eighth aspect of the present invention, a ribbon-shaped polishing cloth arranged along a predetermined moving path and the polishing cloth is moved along the moving path at a predetermined speed by rotating. In addition, a roller-shaped jig for pressing the polishing cloth against the wafer surface, a horizontal movement means for horizontally reciprocating the relative position of the wafer and the jig, and a distance between the wafer surface and the jig are always constant. Since the interval adjusting means for adjusting to and the pattern arrangement storing means for storing the pattern arrangement on the wafer surface are provided, it goes without saying that the preparation and polishing operations can be performed in a short time, and the size can be reduced. It is possible to provide a wafer polishing apparatus capable of extending the life of the polishing cloth.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a wafer polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing an enlarged relationship between the jig shown in FIG. 1 and a wafer surface.

FIG. 3 is a diagram showing a process of the polishing apparatus in FIG.

FIG. 4 is a diagram showing a schematic configuration of a wafer polishing apparatus in Embodiment 3 of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between a cumulative polishing amount and a polishing rate when no dressing is performed.

FIG. 6 is a diagram showing a schematic configuration of a wafer polishing apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a diagram for explaining the principle of a wafer polishing apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing a schematic configuration of a wafer polishing apparatus in embodiment 6 of the present invention.

FIG. 9 is a plan view of a conventional wafer polishing apparatus.

10 is a cross-sectional view taken along the line XX in FIG.

FIG. 11 is a diagram for explaining a problem of a polishing state of the polishing apparatus in FIG.

[Explanation of symbols]

4 wafer, 4a concave portion, 4b convex portion, 5 susceptor,
6 jigs, 7 polishing cloth, 8a to 8h guide rollers,
9 and 16 movement paths, 10 retention section, 13 dressing means, 14 and 15 rollers, 17 optical film thickness meter.

Claims (8)

[Claims] 1. A ribbon-shaped polishing cloth arranged along a predetermined moving path, and by rotating the polishing cloth, the polishing cloth is moved along the moving path at a predetermined speed and the polishing cloth is placed on a wafer surface. A roller-shaped jig for pressing, a horizontal moving means for horizontally reciprocating the relative position of the wafer and the jig, and an interval for adjusting so that the interval between the wafer surface and the jig is always constant. An apparatus for polishing a wafer, comprising: adjusting means. 2. The wafer polishing apparatus according to claim 1, wherein the movement path of the polishing cloth is formed in an endless shape, and a retaining portion of the polishing cloth is provided on the way. 3. The wafer polishing apparatus according to claim 1, wherein the polishing cloth movement path is formed between a pair of rollers arranged so that each end of the polishing cloth can be wound. . 4. The wafer polishing apparatus according to claim 2, wherein dressing means for dressing the polishing cloth is provided in the middle of the movement path of the polishing cloth. 5. A ribbon-shaped polishing cloth arranged along a predetermined movement path, and by rotating the polishing cloth, the polishing cloth is moved along the movement path at a predetermined speed and the polishing cloth is placed on the wafer surface. A roller-shaped jig that presses against
The horizontal movement means for horizontally reciprocating the relative position of the wafer and the jig, the distance adjusting means for adjusting the distance between the wafer surface and the jig to be always constant, and the jig are A polishing apparatus for a wafer, comprising: a pressing force measuring unit that measures a pressing force when the wafer surface is pressed. 6. The wafer polishing apparatus according to claim 5, wherein the polishing is judged to be completed when the pressing force is constantly measured. 7. A ribbon-shaped polishing cloth arranged along a predetermined moving path, and by rotating the polishing cloth, the polishing cloth is moved along the moving path at a predetermined speed and the polishing cloth is placed on a wafer surface. A roller-shaped jig for pressing, a horizontal moving means for horizontally reciprocating the relative position of the wafer and the jig, and an interval for adjusting so that the interval between the wafer surface and the jig is always constant. An apparatus for polishing a wafer, comprising: adjusting means; and film thickness measuring means for measuring the film thickness on the surface of the wafer. 8. A ribbon-shaped polishing cloth arranged along a predetermined moving path, and by rotating the polishing cloth, the polishing cloth is moved along the moving path at a predetermined speed, and the polishing cloth is placed on a wafer surface. A roller-shaped jig for pressing, a horizontal moving means for horizontally reciprocating the relative position of the wafer and the jig, and an interval for adjusting so that the interval between the wafer surface and the jig is always constant. A wafer polishing apparatus comprising: an adjusting unit; and a pattern arrangement storing unit that stores the pattern arrangement on the surface of the wafer.