KR101296538B1 - Grinding apparatus and controlling apparatus for the same - Google Patents

Abstract

In order to polish a large number of wafers, to improve the polishing performance of the wafer, to use the polishing apparatus for a longer time, and to prevent breakage of the polishing apparatus, the upper and lower plates; Outer gear and inner gear which are provided inside and outside of the lower plate; And a plurality of carriers supported by the lower platen, and each carrier is provided with a polishing apparatus in which one wafer is supported.

Description

GRINDING APPARATUS AND CONTROLLING APPARATUS FOR THE SAME}

The present invention relates to a polishing apparatus and a control apparatus of the polishing apparatus.

Semiconductor wafers are made by slicing thin wafers from silicon ingots. When slicing, defects, such as a saw mark of a sawing apparatus, exist in the wafer surface, but the lapping process is performed as a method for removing this defect. Lapping is to polish the wafer surface by loading the wafer and the carrier between the top plate and the bottom plate and supplying a slurry mixed with the abrasive and the dispersant under pressure at a constant pressure. This wrapping results in a somewhat uniform thickness of the wafer.

After lapping, slurry, wafer material, surface material and the like remain on the surface of the wafer, thus cleaning the wafer to remove metal contaminants, other types of particulate impurities, as well as materials such as lapping grit (eg aluminum) and organic residues. Remove

The wafer then removes portions damaged by etching and creates a smooth surface. The final step in a conventional semiconductor wafer fabrication process is a polishing step to make at least one side of the wafer a good and intact surface. Integrated circuit fabrication can be made on this polished surface. The lapping and polishing may be collectively referred to as a polishing device.

In general, the polishing apparatus rotates in opposite directions and includes an upper plate and a lower plate to polish the wafer. Carriers, which can be rotated by being engaged between an inner circumferential gear placed on the lower plate and an outer circumferential gear placed on the central axis, are supported between the upper and lower plates, and a plurality of carriers can be mounted. The carrier rotates in association with the rotational movement of the inner gear and the outer gear in an engaged state between the outer gear and the inner gear. The carrier is placed on the carrier, and the slurry is supplied through the top plate. In this state, the surface of the wafer can be smoothly processed by the friction action caused by the different movements of the upper and lower plates and the carrier and the chemical reaction of the slurry.

The upper and lower plates are generally made of cast iron. As the polishing process is repeated, the upper and lower surfaces may be worn. In particular, since the upper and lower plates are configured in a circle rotated by the rotation axis, due to the difference in the rotational angular velocity, rotation speed, rotation radius, etc. in each part, uneven wear may occur in the upper and lower plates. This may cause local damage to the wafer, cause irregularities, or cause the wafer to be convex or concave.

In addition, when the slurry supplied in the polishing process is supplied unevenly, there is a problem that the surface of the wafer to be polished is unevenly polished.

The present invention is proposed to improve the above-mentioned problem, so that the wafer can be uniformly polished in the polishing apparatus, the supply of slurry can be strictly controlled, and the polishing of the wafer can be controlled locally. In addition, by increasing the number of wafers that can be placed in the same polishing apparatus, it is possible to improve the polishing performance and polishing quality of the wafer, and to increase the service life of the polishing apparatus by preventing the occurrence of stress of the polishing apparatus. We propose a control device.

In the polishing apparatus according to the present invention, an upper plate provided with a plurality of slurry supply holes; A lower surface meshing with the upper surface; Outer gear and inner gear which are provided inside and outside of the lower plate; At least one carrier supported on the lower plate; And at least one wafer supported by the at least one carrier, wherein the slurry supply holes can be divided into at least two groups in which the supply flow rate of the slurry varies according to the positions of the carriers.

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According to another aspect of the present invention, there is provided a control apparatus for a polishing apparatus, the apparatus for controlling supply of slurry to a plurality of slurry supply holes provided on a surface plate of the polishing apparatus, the apparatus comprising: at least one hydraulic pump; And at least two flowmeters provided at an outlet side of the at least one hydraulic pump, wherein the at least two flowmeters are configured such that the flow rate of the slurry varies in a group of dividing the slurry supply holes of the polishing apparatus into at least two or more. It is characterized by controlling.

According to the present invention, a large number of wafers can be polished, the polishing performance of the wafer can be improved, the polishing apparatus can be used for a longer time, and the effect of preventing the damage of the polishing apparatus can be expected.

1 is a perspective view of a polishing apparatus according to a first embodiment.
2 is a plan view of a lower plate for observing a carrier placed on the lower plate;
3 is a plan view of an upper plate.
4 is a block diagram illustrating a control device of the polishing apparatus according to the first embodiment.
5 is a view for explaining a connection state of the slurry supply hole in the first embodiment.
6 is a plan view of the lower plate according to the second embodiment;
7 is an exploded perspective view of the polishing apparatus according to the third embodiment.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the appended embodiments, and those skilled in the art who understand the spirit of the present invention can easily add, change, delete, and add other elements included in the scope of the same idea. It may be proposed, but this is also included within the scope of the present invention.

≪ Embodiment 1 >

1 is a perspective view of a polishing apparatus according to a first embodiment.

Referring to FIG. 1, the polishing apparatus is provided with an upper plate 2 and a lower plate 1. The lower plate 1 is provided with an outer cycle gear 3 and an inner cycle gear 4 which are rotatable. A plurality of carriers 5 are placed between the outer gear 3 and the inner gear 4. One wafer is placed on each carrier 5. In this structure, when the outer gear 3 and the inner gear 4 rotate at a constant rate, the carrier 5 can rotate in a predetermined position. While the carrier 5 is being rotated, the upper and lower plates 2 and 1, which can be in contact with the upper and lower surfaces of the wafer, can perform polishing while contacting the wafer. The top plate 2 is also provided with a slurry supply hole 6 through which the slurry is supplied. The slurry supply hole 6 may be arranged uniformly with respect to the entire area of the upper plate 2 so as to cope with various arrangements of carriers and local control of the polishing state, and later, a slurry supply hose or the like. Only the connection state of can be changed.

According to the polishing apparatus as shown, only the rotational movement can be performed at a fixed position with respect to the lower plate, without the wafer rotating about the lower plate. Therefore, it is possible to perform specific processing on the wafer placed at a specific position. For example, it is possible to obtain a high polishing efficiency by injecting a large amount of slurry at a position where a specific wafer is placed, and to polish the wafer to a specific shape and structure by locally changing the shape of the surface on which the specific wafer is placed. It would also be possible. Thereby, the effect which can control grinding | polishing of a wafer locally can be acquired.

On the other hand, since the wafer does not move with respect to the lower plate and the upper plate, and polishing is continued at the same position, it is possible to obtain an advantage of improving the uniformity of the height of the wafer.

2 is a plan view of the carrier placed on the lower platen.

Referring to FIG. 2, a plurality of carriers 5 are engaged with each other in the interval between the outer gear 3 and the inner gear 4 in the lower plate 1. Looking at the rotational state of the carrier shown by way of example can be understood the rotational movement of each carrier. Briefly, when the outer gear 3 rotates clockwise, the carrier 5 in contact with the outer gear rotates counterclockwise. And when the inner gear 4 rotates counterclockwise, the carrier 5 which contacts the inner gear 4 rotates counterclockwise. And the carrier 5 located in the center is rotated clockwise. In order to carry out such a rotating action of the carrier 5, the carrier 5 lying at each distance from the center of the lower plate 1 is provided in the same number at different distances.

As described above, not only the polishing action is performed by rotating the respective carriers 5 but also the number of wafers that can be polished at once on the same size plate can be obtained. As shown in FIG. 6, which is a view of the second embodiment, in a carrier structure in which four wafers are placed in a single carrier, 20 wafers can be polished in one polishing operation. However, as can be seen in the figure of Fig. 2, it can be estimated that 27 wafers can be polished at once when one wafer is polished with each carrier. As a result, it can be seen that the number of polished wafers obtained by performing a single polishing operation in a polishing apparatus of the same size increases approximately 35%.

In addition, in the case of a carrier on which a plurality of wafers are seated, by rotating each carrier, it is possible to suppress partial stress concentration phenomenon that may occur in the gap between the carriers. This can prevent the deterioration of the polishing apparatus and increase the service life of the polishing apparatus.

On the other hand, in the first embodiment, since each carrier 5 can perform only the rotational movement, it is possible to accurately control the amount of slurry injected for each carrier.

FIG. 3 is a plan view of the top plate, and the supply amount control of the slurry will be described with reference to FIG. 3. Starting from the inside, the first group 61, the second group 62, and the third group 63 may be set, and thus the amount of slurry supplied through the slurry supply hole 6 may be varied for each group. As a result, the degree of polishing can be adjusted differently. For example, the first group 61 may supply a large amount of slurry in order to increase the amount of polished or to obtain a wafer having a high flatness as a supply state of the slurry supplied to the innermost wafer. The group 62 can supply a medium amount by making the grinding | polishing medium medium by the supply state of the slurry supplied to the wafer located in the middle. Finally, the third group 63 can supply the least amount of slurry to reduce the amount of polishing to be supplied by the supply state of the slurry supplied to the outermost wafer.

In order to achieve the effect of supplying the appropriate slurry, separate wandering systems may be installed for each of the groups 61, 62, and 63.

According to the first embodiment, since the wafer may be fixed in position with respect to the surface plate, it is possible to control the supply amount of the slurry so as to achieve the polishing degree set for each wafer. That is, when the degree of pressure exerted by the top plate becomes larger toward the outside, an even polishing degree is achieved by increasing the amount of slurry supplied to the inner wafer, that is, the wafer belonging to the first group 61. You can do it.

In addition, the division of each group shown in FIG. 3 is only an illustration. For example, instead of varying the amount of slurry supplied by performing grouping in the radial direction as shown in the examples, the amount of slurry supplied by performing grouping in the circumferential direction may be changed. In such a case, when a problem arises in slicing, and when it is necessary to change the degree of polishing for a specific group of wafers, the wafers of the specific group are arranged in a specific circumferential direction and high polishing is achieved compared to other wafers. You can do it.

4 is a block diagram illustrating a control device of the polishing apparatus according to the first embodiment.

Referring to FIG. 4, when a different amount of slurry is to be supplied, slurry supplied from a single or two or more hydraulic pumps 7 is supplied in different amounts through different wanders 71, 72, and 73. Indicates what can be done.

For example, the first flow meter 71 is connected to the first group 61, the second wander meter 72 is connected to the second group 62, and the third wander meter 73 is the third group. May be connected to (63). At this time, as shown in FIG. 3 and the description thereof, the first flow meter 71 is opened relatively large to supply a large amount of slurry, and the third flow meter 73 is opened relatively small to supply a small amount of slurry. I can do it. Of course, it is only an example to be presented, it is also possible to use a plurality of hydraulic pumps instead of one. As another example, the number of groups 61, 62, 63 and the number of flow meters 71, 72, 73 are not limited to three, but can be adjusted more or smaller as needed. Of course, the connection state of the flowmeter can be changed to the number of different cases.

As will be explained, according to the first embodiment, the amount of slurry supplied can be more actively controlled. As a result, the degree of polishing of the wafer or the flatness of the wafer can be more strictly controlled.

5 illustrates a connection state of the slurry supply hole in the first embodiment.

Referring to FIG. 5, the slurry supply hole corresponding to the center of each carrier is connected to the discharge part of the flowmeter, so that the slurry supply holes of each carrier are supplied with the slurry from the same flowmeter along the first group 61. can see.

According to the first embodiment, the wafer can be polished by a rotating action in a state where the wafer is stopped with respect to the surface plate, so that the wafer can be polished uniformly, and the polishing of the wafer can be controlled in a locally controlled state. In addition, the number of wafers that can be placed in a polishing apparatus of the same size is increased compared to a carrier on which a plurality of wafers are seated, thereby increasing the number of wafers polished at one time, thereby increasing the use efficiency of the polishing apparatus. In addition, since the supply amount of the slurry can vary depending on the structure / shape / arrangement of the polishing apparatus and the state of the wafer, the effect of improving the polishing quality of the wafer can be expected. In addition, since the stress generated in the gap between the carriers is eliminated by the movement of the carrier of large size, the service life of the polishing apparatus can be increased.

≪ Embodiment 2 >

In the first embodiment, the control device of the polishing apparatus for varying the supply flow rate of the slurry for each group can be used differently from the configuration in which only one wafer is placed on one carrier. The second embodiment shows such an embodiment. However, in the parts to which the same description can be applied, the description of the first embodiment is used, and only the parts to be changed will be described in detail.

6 is a plan view of the lower plate according to the second embodiment.

Referring to FIG. 6, four wafers are placed in one carrier 70 and five carriers 70 are mounted in one polishing apparatus, and the carrier is rotated by gears engaged with the carrier 70. It rotates and the wafer rotates about the carrier.

In this case, the polishing action may be changed by various other factors, but as an example, since the contact portion of the surface plate corresponding to the center of the carrier has a great chance of contact with the wafer, more slurry may be supplied. Since the contact portion of the surface plate corresponding to the outside has a small contact opportunity with the wafer, it is desirable to reduce the supply amount of the slurry.

In this case, the supply amount of the slurry to the second group 82 may be increased, and the supply amount of the slurry to the first group 81 and the third group 83 may be reduced.

In the second embodiment, even when the wafer shows the rotational state of idle, the supply amount of the slurry may be different for each group, thereby improving the processing state of the wafer. However, the adjustment of the supply flow rate of the slurry can have a greater effect in the case of the embodiment in which the local control of the polishing can be performed for each wafer as in the first embodiment. In other words, in the case where the wafer has only rotating movement without revolving movement, it is possible to obtain an effect that more precise local polishing can be controlled by appropriately supplying the slurry to a predetermined position.

Third Embodiment

In the first embodiment and the second embodiment, the flow rate of the slurry is changed for each group so as to obtain an optimum polishing state. In addition, in order to achieve these objects, in the first embodiment, one wafer is placed in one carrier, and in the second embodiment, a plurality of carriers are placed in a single polishing apparatus, and at least two in each carrier. Two wafers to be polished. The idea of the present invention is not limited to this embodiment, but a single carrier may be placed in a single polishing apparatus, and a plurality of wafers may be placed in the single carrier. The third embodiment presents such a polishing apparatus. However, in the parts to which the same description can be applied, descriptions of the first embodiment and the second embodiment are used, and only the parts to be changed will be described in detail.

7 is a perspective view of a polishing apparatus according to a third embodiment.

Referring to FIG. 7, the polishing device according to the third embodiment is provided with an upper plate 2 and a lower plate 1. The lower plate 1 is provided with an outer cycle gear 3 and an inner cycle gear 4 which are rotatable. A single carrier 55 lies between the outer gear 3 and the inner gear 4. One feature of this embodiment is that the carrier placed in the gap between the upper plate 2 and the lower plate 1 is characterized by one.

In the single carrier 55, an inner gear 56 in contact with the outer gear 3 and an outer gear 57 in contact with the inner gear 4 are provided in the form of inner and outer edges, respectively. In addition, the first seating portion 58, the second seating portion 59, and the third seating portion 60 are provided in an order close to the inner gear 56, and the wafer is placed therein. The number of seating portions may be provided in the same manner as the number of carriers in the first embodiment.

In this structure, when the outer gear 3 and the inner gear 4 rotate at the same angular velocity?, The single carrier 55 can itself rotate. While the single carrier 55 is rotated, the upper surface plate 2 may perform polishing while contacting the wafer. The top plate 2 is also provided with a slurry supply hole 6 through which the slurry is supplied. The slurry supply hole 6 may be arranged uniformly with respect to the entire area of the upper plate 2 so as to cope with various arrangements of carriers and local control of the polishing state, and later, a slurry supply hose or the like. Only the connection state of can be changed. For example, the first group 61, which is a slurry supply hole aligned with the first seating part 58, the second group 62, which is a slurry supply hole aligned with the second seating part 59, and the third seating. The third group 63, which is a slurry supply hole aligned with the part, can be set. In addition, the supply amount of the slurry through the slurry supply hole 6 may be changed for each group. Specifically, when the single carrier 55 rotates at the same angular velocity, a large amount of slurry is supplied to the first group 61 which has the greatest polishing action by the action with the upper plate 2, and A small amount of slurry may be supplied to the third group 63 which has a small polishing action.

Another embodiment included in the spirit of the present invention is further presented. For example, in the embodiment it is described that the grouping for the supply of the slurry is separated from each other in an annular, but not limited thereto, and a large amount of slurry only for the slurry supply hole in the circumferential direction, or only a specific position of the slurry supply hole It can also be supplied. As another example, when a polishing apparatus is large, one carrier is also large, and in this case, a plurality of wafers may be seated on one carrier to perform polishing, but such a structure must overcome efficiency. There is a problem.

According to the present invention, a large number of wafers can be polished, the polishing performance of the wafer can be improved, the polishing apparatus can be used for a longer time, and the effect of preventing the damage of the polishing apparatus can be expected. Thus, the applicability is expected to be higher in modern times where high performance wafers are required due to improved integration of semiconductors.

5: carrier
55: single carrier
61, 62, 63: Slurry Feed Group

Claims (15)

An upper plate having a plurality of slurry supply holes;
A lower surface meshing with the upper surface;
Outer gear and inner gear which are provided inside and outside of the lower plate;
At least one carrier supported on the lower plate; And
At least one wafer supported on the at least one carrier,
The slurry supply holes, the polishing apparatus can be divided into at least two groups in which the supply flow rate of the slurry varies by position of the carrier. The method of claim 1,
And one carrier supported on the lower plate and the outer gear and the inner gear rotate in the same direction. The method of claim 1,
There are a plurality of carriers supported on the lower plate,
The polishing apparatus of any one of the plurality of carriers rotates in engagement with an adjacent carrier. The method of claim 1,
The slurry supply holes are divided into at least two types based on a radial distance from the outer gear,
Polishing apparatus that is supplied with the same amount of slurry to the slurry supply holes are divided into the same type. The method of claim 1,
Polishing apparatus that the slurry supply holes are provided at equal intervals in the upper plate. A device for controlling the supply of slurry to a plurality of slurry supply holes provided on the surface plate of the polishing apparatus,
At least one hydraulic pump; And
At least two flowmeters are provided at the outlet side of the at least one hydraulic pump,
And the at least two flowmeters control the supply flow rate of the slurry to a group of dividing the slurry supply holes of the polishing apparatus into at least two or more. The method according to claim 6,
The slurry supply hole is provided in the upper plate of the polishing device, the same group of the slurry supply hole is a slurry supply hole of the slurry supply hole located at the same distance in the radial direction from the center of the lower plate. delete delete delete delete delete delete delete delete

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