JP2007180309A - Polishing device and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polishing device and method capable of improving the use efficiency of slurry by a simple structure, and capable of preventing the change of the polishing characteristics. <P>SOLUTION: An outer surrounding wall 108 for surrounding a part of the perimeter of a top ring 107 abutting a semiconductor wafer 106 is provided on a polishing pad 102 stuck on the top face of a turntable 101. This outer surrounding wall 108 is constructed in the shape having a flexure 108a and holders 108b extending from the ends of this flexure 108a, e.g. in a U-shape as seen in the plan view, and the flexure 108a is pressed against the polishing pad 102 to partition it to form a polishing region S. The slurry 105 is locally supplied to this polishing region S to polish the semiconductor wafer 106, so that the use efficiency of the slurry 105 is improved. Further, the slurry is discharged from the opening on the side of both ends of the flexure 108a to suitably replace the slurry 105 during the polishing to make the polishing characteristics stable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a polishing apparatus and a polishing method, and more particularly, to a CMP (abbreviation of chemical mechanical polishing, hereinafter referred to as CMP) apparatus and a CMP method.

2. Description of the Related Art In recent years, various microfabrication techniques have been performed with increasing density and miniaturization of semiconductor devices. Among them, the CMP technique, which is a chemical mechanical polishing technique, has become an indispensable technique indispensable for planarizing an interlayer insulating film formed on a semiconductor wafer.

However, the conventional CMP apparatus used for CMP has a problem that more slurry than necessary is consumed during polishing.

Usually, in order to perform stable CMP of semiconductor wafers, etc., slurry is dropped near the center of the polishing pad, and the slurry is spread over the entire polishing pad by the action of centrifugal force, and then held inside the retainer ring of the top ring. This is done by pressing the semiconductor wafer against the polishing pad. However, in the case of a single top ring in which a semiconductor wafer is pressed and polished one by one against a single polishing pad, the slurry is dropped on the polishing pad, and then on the opposite side of the top ring from the center of the polishing pad. Slurry flowing in the direction is discharged outside the polishing pad with little contribution to polishing. Therefore, a large amount of slurry is wasted, and the use efficiency of the slurry is extremely deteriorated.

In contrast, a groove is provided on the entire upper surface of the retainer ring for locking the semiconductor wafer, and fine passages connected to the groove are provided at a plurality of locations on the inner surface of the retainer ring. There is a CMP apparatus that supplies slurry locally to a polishing pad region between an inner peripheral surface of a retainer ring and an outer peripheral surface of a semiconductor wafer by supplying the slurry (see, for example, Patent Document 1). According to this CMP apparatus, since the slurry supplied between the semiconductor wafer and the retainer ring is processed so as not to flow outside the retainer ring, the amount of slurry discharged without contributing to polishing is reduced. It can be reduced and the use efficiency of the slurry can be improved.

However, the CMP apparatus modified in this way can efficiently use the slurry, but requires a complicated process because it requires a retainer ring having a special structure. In addition, since the slurry supplied between the semiconductor wafer and the retainer ring does not sufficiently flow out of the retainer ring, the slurry containing the semiconductor wafer shavings or the like stays in the area surrounded by the retainer ring, and is polished. There is a possibility that the problem of deteriorating the characteristics may occur.
JP 2000-317812 (FIG. 3)

The present invention has been made to solve the above problems, and provides a polishing apparatus and a polishing method capable of improving the use efficiency of slurry with a simple structure and preventing deterioration of polishing characteristics. The purpose is to do.

In order to achieve the above object, a polishing apparatus according to an aspect of the present invention includes a turntable to which a polishing pad is attached, a top ring that holds a semiconductor wafer and presses the semiconductor wafer on the polishing pad, An outer peripheral wall that surrounds a part of the outer periphery of the semiconductor wafer and contacts the polishing pad, and a slurry supply pipe that supplies slurry onto the polishing pad region between the outer periphery of the semiconductor wafer and the outer peripheral wall. It is characterized by.

The polishing method according to another aspect of the present invention includes a step of bringing an outer wall into contact with a polishing pad attached to a turntable, and a step of supplying slurry to the polishing pad region surrounded by the outer wall. And a step of pressing a semiconductor wafer held on a top ring against the polishing pad region to which the slurry is supplied.

According to the present invention, it is possible to provide a polishing apparatus and a polishing method capable of improving the use efficiency of the slurry with a simple structure and preventing the deterioration of the polishing characteristics.

Hereinafter, a polishing apparatus and a polishing method according to embodiments of the present invention will be described with reference to the drawings.

First, the configuration of the polishing apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1A is a cross-sectional view schematically showing a configuration of a polishing apparatus according to Embodiment 1 of the present invention, and FIG. 1B is a plan view thereof.

As shown in FIG. 1, in the polishing apparatus according to the present embodiment, a polishing pad 102 is attached to the upper surface of a turntable 101, and the turntable 101 is rotated horizontally by driving a motor (not shown). A top ring 107 that can move up and down is arranged. At the lower end surface of the top ring 107, the semiconductor wafer 106 is held by suction with the surface to be processed facing the surface of the polishing pad 102. Further, an annular retainer ring 104 is provided on the lower end surface of the top ring 107 for locking the semiconductor wafer 106 during polishing. The outer periphery of the semiconductor wafer 106 is surrounded by the inner peripheral surface of the retainer ring 104. ing.

The retainer ring 104 has the same structure as a retainer ring used in a general CMP apparatus. For example, when the semiconductor wafer 106 held on the top ring 107 is pressed against the polishing pad 102 during polishing, the retainer ring 104 is retained. The thickness is designed to create a gap between the lower end surface of the ring 104 and the polishing pad 102. The retainer ring 104 is not particularly necessary when the semiconductor wafer 106 is strongly adsorbed to the top ring 107 and there is no risk of detachment from the top ring 107 during polishing.

Although the details will be described later, an outer wall 108 is provided above the turntable 101. The outer surrounding wall 108 surrounds a part of the outer peripheral surface of the top ring 107 and is disposed in contact with the surface of the polishing pad 102.

Above the turntable 101, a slurry supply pipe 103 for supplying the slurry 105 to the polishing region S on the polishing pad 102 surrounded by the outer wall 108, and pure water of water polish to the polishing region S A water-polished pure water supply pipe 110 for supplying water is provided.

Further, a dressing pure water supply pipe 112 for supplying pure water during dressing by the dresser 111 is provided above the turntable 101 in a region outside the outer wall 108.

Here, the outer wall 108 will be described in detail.

As shown in FIG. 1B, the outer wall 108 has a shape having a curved portion 108a and a support portion 108b extending from the end of the curved portion 108a, for example, a planar U-shape, and is curved. The part 108 a is disposed on the polishing pad 102, surrounds a part of the outer peripheral surface of the top ring 107, and defines a part of the polishing pad 102 as a polishing region S. Both ends of the curved portion 108a are predetermined so that the top ring 107 and the outer wall 108 do not collide when the top ring 107 is horizontally moved to the outer edge of the polishing pad 102 after polishing and then overhanged from the polishing pad 102. Has an interval L. In the present embodiment, for example, the distance L between both ends of the curved portion 108 a is set to ¼ of the length of the entire outer edge of the polishing pad 102.

Further, the curved portion 108a of the outer wall 108 and the polishing pad 102 may be brought into close contact with each other with a certain pressing force in order to prevent the supplied slurry 105 from leaking to the outside of the curved portion 108a at these contact interfaces. desired. However, if the adhesion is too strong, the polishing pad 102 and the curved portion 108a are worn and become thinner as the polishing time increases.

Therefore, in order to press the outer wall 108 against the polishing pad 102 with a certain moderate load, the end portion of the support portion 108b of the outer wall 108 is connected to the turntable 101 via the elastic body 114 as shown in FIG. The outer casing 109 is fixed. With this elastic body 114, the pressing load of the curved portion 108a of the surrounding wall 108 on the polishing pad 102 can be appropriately adjusted. In this embodiment, this pressing load is set to 100 gf / cm ² or less. The curved portion 108a of the outer wall 108 is required to have a high chemical resistance and high wear resistance in addition to having a mechanical strength that can withstand the dynamic frictional force received from the rotating polishing pad 102. It is made of polyphenylene sulfide (PPS), fluorine resin, or the like.

In this embodiment, the curved portion 108 a of the outer wall 108 may be processed to have a flat bottom surface portion that comes into contact with the polishing pad 102 to improve the adhesion to the polishing pad 102. Further, in order to suppress load concentration on the polishing pad 102, the corners of the lower surface may be chamfered.

The CMP process using the polishing apparatus according to this embodiment of the present invention will be described below.

First, the end of the support part 108b of the outer wall 108 is fixed to the casing 109 of the turntable via an elastic body 114, and the curved part 108a of the outer wall 108 is brought into contact with the polishing pad 102 with a predetermined pressure by the elastic body 114. Then, the turntable 101 is rotated at a predetermined rotation number in the direction of the arrow in FIG. 1B within a horizontal plane by a drive motor (not shown).

Next, the slurry 105 is dropped from the slurry supply pipe 103 onto the polishing region S of the polishing pad 102 surrounded by the curved portion 108a. In this manner, the slurry 105 is locally supplied only to the polishing region S of the polishing pad 102 surrounded by the curved portion 108a, not to the entire surface of the polishing pad 102.

Here, the slurry supply amount is adjusted so that the slurry 105 does not overflow from the upper portion of the curved portion 108a. However, in order to ensure the minimum thickness of the slurry layer necessary for stable polishing, the height of the curved portion 108a is set higher than a certain level.

Further, after finishing the polishing pad for sufficiently wetting the polishing pad 102 with the slurry 105, the top ring 107 holding the semiconductor wafer 106 is moved above the polishing region S of the polishing pad 102 supplied with the slurry 105. To the polishing pad 102 while being rotated in the same direction as the turntable 101 in a horizontal plane by a drive motor (not shown), and the surface to be processed of the semiconductor wafer 106 is pressed against the polishing pad 102 with a predetermined pressure. To do. In this manner, the surface to be processed of the semiconductor wafer 106 is polished by rubbing on the rotating polishing pad 102 through the slurry 105. At this time, for example, the slurry 105 can move into and out of the retainer ring 104 from the gap between the polishing pad 102 and the retainer ring 104 or an opening provided in the retainer ring 104.

However, at this time, the dropping position A of the slurry 105 is set closer to the center of the polishing pad 102 than the top ring 107 in the polishing region S described above. This is because the slurry 105 flowing out toward the outer edge of the polishing pad 102 due to the centrifugal force is sufficiently supplied to the semiconductor wafer 106 held by the top ring 107.

After the polishing with the slurry 105 is completed, water polishing pure water is dropped from the water polish pure water supply pipe 110 onto the polishing pad 102 to perform water polishing, and the slurry 105 attached to the semiconductor wafer 106 is washed away. The applicable range of the dripping position B of the pure water for water polishing is the same as the dripping position A of the slurry 105. At the time of this water polishing, most of the attached dirt due to the slurry 105 such as the interface between the curved portion 108a and the polishing pad 102 is also washed away.

Next, the polished semiconductor wafer 106 is horizontally moved to the outer edge of the polishing pad 102 and overhanged, and then transferred to a post-cleaning module (not shown) and subjected to post-cleaning processing. In the meantime, the surface of the polishing pad 102 is dressed by the dresser 111. This dressing is performed by rubbing the dresser 111 on the polishing pad 102 outside the curved portion 108 a, and the pure water for dressing is applied to the polishing pad 102 outside the curved portion 108 a from the dressing pure water supply pipe 112. It is dripped. The dripping position C is adjusted to be closer to the center of the polishing pad 102 than the dresser 111. This is because the dressing 111 is sufficiently supplied with pure water for dressing that flows toward the outer edge of the polishing pad 102 by the action of centrifugal force.

As described above, when the dressing is completed, the semiconductor wafer 106 to be polished next is similarly polished.

Thus, in the polishing apparatus according to the present embodiment, the slurry 105 is locally supplied only to the polishing region S surrounded by the curved portion 108a of the outer wall 108 of the polishing pad 102, not the entire surface of the polishing pad 102. This makes it possible to secure the minimum thickness of the slurry layer required for polishing the semiconductor wafer 106 with a small amount of the slurry 105, as compared with a normal CMP apparatus, thereby reducing the amount of slurry used for polishing. And the use efficiency of the slurry 105 can be improved.

Further, in the conventional CMP apparatus in which the slurry use efficiency is improved by remodeling the retainer ring, a groove is provided on the entire upper surface of the retainer ring surrounding the semiconductor wafer, and fine slurry is formed at a plurality of locations on the inner surface of the retainer ring. A retainer ring with a special structure that forms a supply passage is used, and complicated processing is required for the apparatus. Furthermore, in this conventional CMP apparatus, the retainer ring has a substantially sealed structure so that the slurry supplied between the retainer ring and the semiconductor wafer during polishing is sufficiently held inside the retainer ring so as not to leak to the outside. ing. Therefore, there is a problem that the slurry used for polishing, that is, the slurry waste liquid or the discharge of the polishing waste stays inside the retainer ring, and the polishing characteristics in the polishing process of the semiconductor wafer deteriorate.

On the other hand, the CMP apparatus according to the present embodiment is obtained by attaching a surrounding wall 108 having a simple structure such as a plane U-shape to a normal CMP apparatus, and thus does not require complicated processing. . Further, since the outer wall 108 is opened at the outer edge of the polishing pad 102, the slurry waste liquid and polishing waste can be sufficiently discharged, and the unused slurry 105 can always be supplied to the semiconductor wafer 106. Thus, it is possible to stabilize the polishing characteristics.

From the above, according to the present embodiment, it is possible to provide a polishing apparatus and a polishing method capable of improving the use efficiency of the slurry with a simple structure and preventing the deterioration of the polishing characteristics.

(Modification of Example 1)
FIG. 2 is a plan view showing a schematic configuration of a polishing apparatus according to a modification of the first embodiment.

In this modification, the outer wall 208 has a shape having a curved portion 208a and a support portion 208b extending to one end of the curved portion 208a, for example, a fishhook shape, and the support portion 208b is a casing outside the turntable 101. The second embodiment is different from the first embodiment in that it is fixed to 109 and the other end of the curved portion 208a is brought into contact with the polishing pad 102 in the vicinity of the outer edge of the turntable 101 as a free end. Since the other constituent parts are the same, the same constituent parts are denoted by the same reference numerals and detailed description thereof is omitted.

  That is, the outer wall 208 is fixed to the casing 109 of the turntable 101 via the elastic body 114 at a support portion 208b provided to extend to one end of the curved portion 208a. On the other hand, the other end portion of the curved portion 208a is not fixed and is set as a free end, and the free end is provided so as to contact the polishing pad 102 near the outer edge of the turntable 101 so as not to protrude outward from the outer edge. ing. Here, one end of the curved portion 208a of the outer wall 208 may be fixed and the other end may be a free end.

  As a result, the slurry waste liquid, polishing scraps, and the like are also discharged from the gap between the free end of the curved portion 208a and the outer edge of the turntable 101 in addition to the slurry discharge portion shown in the first embodiment.

  According to the polishing apparatus of the modified example, as in the first embodiment, it is possible to improve the use efficiency of the slurry with a simple structure, and discharge of slurry waste liquid, polishing waste, and the like compared to the polishing apparatus of the first embodiment. Thus, the slurry can be replaced more efficiently, and the polishing characteristics can be stabilized.

Next, the configuration of a polishing apparatus according to Embodiment 2 of the present invention will be described with reference to FIG.

FIG. 3 is a plan view showing a schematic configuration of a polishing apparatus according to Embodiment 2 of the present invention.

The present embodiment is different in that a slit 315 for discharging slurry is provided in the curved portion 108a of the outer peripheral wall 108 of the polishing apparatus according to the first embodiment described above, and the other configurations are the same. About a structure, the same number is attached | subjected and detailed description is abbreviate | omitted.

That is, in the polishing apparatus according to the present embodiment, the polishing pad 102 is attached to the upper surface of the turntable 101 as shown in FIG. A top ring 107 for adsorbing and holding the wafer 106 is disposed, and an annular retainer ring 104 for locking the semiconductor wafer 106 during polishing is provided on the lower end surface of the top ring 107. .

Above the turntable 101, a slurry supply pipe 103, a water polished pure water supply pipe 110, and a dressing pure water supply pipe 112 are provided.

Furthermore, as shown in FIG. 3, the outer periphery of the top ring 107 is surrounded by an outer wall 308 disposed in contact with the polishing pad 102.

The outer wall 308 according to the present embodiment is fixed to the casing 109 of the turntable 101 via the elastic body 114 in the support portion 308b as in the first embodiment. Further, as shown in FIG. 3, the outer surrounding wall 308 has a U-shape, and the curved portion 308 a in contact with the polishing pad 102 in the outer surrounding wall 308 is opened at the outer edge of the polishing pad 102. Has been. In the present embodiment, for example, the distance L between both ends of the curved portion 308 a is set to ¼ of the length of the entire outer edge of the polishing pad 102.

Further, the outer wall 308 according to the present embodiment is provided with a plurality of slits 315. The slit 315 is provided in order to efficiently replace the slurry 105 supplied to the semiconductor wafer 106 by adjusting the discharge amount of the slurry waste liquid or the like.

The CMP process using the polishing apparatus according to the above embodiment will be described below. Here, the same process as the CMP process by the polishing apparatus shown in the first embodiment will be described with the details omitted.

First, the support part 308b of the outer wall 308 is fixed to the casing 109 of the turntable 101 via the elastic body 114, and the curved part 308a of the outer wall 308 is brought into contact with the polishing pad 102 with a predetermined pressure by the elastic body 114. The turntable 101 is rotated. Next, the slurry 105 is locally supplied to the polishing region S of the polishing pad 102 surrounded by the curved portion 308a.

Here, the slurry 105 supplied to the polishing region S surrounded by the curved portion 308 a flows out to the outside of the polishing region S through the slit 315.

Thereafter, the top ring 107 holding the semiconductor wafer 106 is rotated and pressed against the polishing region S to which the slurry 105 is supplied to polish the semiconductor wafer 106. At this time, the dropping position A of the slurry 105 is set closer to the center of the polishing pad 102 than the top ring 107 in the polishing region S.

Subsequently, pure water for water polishing is dropped onto the polishing pad 102 from the water polish pure water supply pipe 110 to wash away the slurry 105 adhering to the semiconductor wafer 106. The applicable range of the dripping position B of the pure water for water polishing is the same as the dripping position A of the slurry 105.

The semiconductor wafer 106 thus polished is transferred to a post cleaning module (not shown) and subjected to post cleaning processing. Meanwhile, pure water for dressing is dropped on the polishing pad 102 outside the outer wall 308 during this period, and the polishing pad 102 is dressed by the dresser 111. The dripping position C of the pure water for dressing is positioned closer to the center of the polishing pad 102 than the dresser 111.

As described above, in the polishing apparatus according to the present embodiment, similarly to the polishing apparatus according to the first embodiment, the outer wall 308 of the polishing pad 102 is not the entire surface of the polishing pad 102 by the outer wall 308 having a simple structure. The slurry 105 is locally supplied and polished only in the polishing region S surrounded by the curved portion 308a. Therefore, the amount of slurry used for polishing can be reduced, and the use efficiency of the slurry can be improved.

Furthermore, in the polishing apparatus according to the present example, a part of the slurry 105 supplied to the polishing region S surrounded by the curved portion 308a of the outer wall 308 is discharged from the open portion on the end side of the curved portion 308a. In addition to this, it can flow out of the polishing region S through the slit 315 of the curved portion 308a. As a result, it is possible to sufficiently discharge slurry waste liquid, polishing scraps, and the like, and it is possible to replace the slurry more effectively than the polishing apparatus according to the first embodiment, thereby stabilizing the polishing characteristics.

In the above embodiment, by changing the position, size, quantity, and the like of the slits 315, the discharge amount of slurry waste liquid and the like can be adjusted. Furthermore, for example, if means for changing the size of the slit 315 during polishing is provided, the discharge amount of slurry waste liquid and the like can be adjusted even during polishing.

Next, the configuration of a polishing apparatus according to Embodiment 3 of the present invention will be described with reference to FIG.

FIG. 4A is a cross-sectional view showing an outline of an outer wall provided with a temperature control function, and FIG. 4B is a plan view thereof.

In each of the above-described examples, for example, Example 1, when the dynamic frictional force increases between the semiconductor wafer 106 and the polishing pad 102 during polishing, the surface temperature of the polishing pad 102 is abnormally increased, and the polishing characteristics are adversely affected. There is. In addition, in order to improve the polishing rate, it may be desired that the surface temperature of the polishing pad 102 be positively increased. Therefore, in this embodiment, an outer wall 408 having a temperature adjustment function is used that adjusts the temperature of the surface of the polishing pad 102 during polishing by using heat exchange by contact with the polishing pad 102.

That is, as shown in FIG. 4, the curved portion 408a of the outer wall 408 that comes into contact with the polishing pad 102 has a hollow structure, and the inlet of the pipe 416 of the temperature control water circulation device (not shown) is connected to, for example, the hollow portion. Connect to one end of both ends.

For example, the temperature adjusting water 417 adjusted to various temperatures is passed through the curved portion 408a of the outer wall 408 to change the temperature of the curved portion 408a itself of the outer wall 408, and the outer wall 408 is further polished during polishing. Allows the heat generated from the surface of the polishing pad 102 to be absorbed or the heat to be applied to the surface of the polishing pad 102, and the temperature of the surface of the polishing pad 102 to be adjusted during polishing. become.

As the material of the outer surrounding wall 408, for example, high thermal conductive plastic or SiC may be used. In this case, only the bottom surface of the outer wall 408 may be changed to a material having high thermal conductivity.

Here, the temperature adjusting water 417 is passed through the outer wall 408, but a fluid such as a gas whose temperature has been adjusted may be passed.

As a result of the experiment, the polishing apparatus that does not have the temperature adjustment function has the temperature adjustment function of this embodiment when the surface temperature of the polishing pad 102 rises from room temperature to 60 ° C. during the polishing and adversely affects the CMP performance. In this polishing apparatus, it was confirmed that the maximum temperature of the surface of the polishing pad 102 during polishing was suppressed to 40 ° C. when 15 ° C. temperature-controlled water was passed through the outer wall 408.

In the above polishing apparatus according to the present embodiment, as with the polishing apparatus according to the first embodiment, the use efficiency of the slurry used for polishing can be improved by providing the outer wall 408 with a simple structure. It is possible to sufficiently discharge the slurry waste liquid and polishing scraps, to effectively replace the slurry, and to stabilize the polishing characteristics.

Furthermore, since the temperature adjusting water is circulated with the curved portion 408a of the outer wall 408 in contact with the polishing pad 102 as a hollow structure, the temperature of the surface of the polishing pad 102 during polishing can be adjusted, and the polishing characteristics can be controlled.

  Next, a polishing apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5A is a cross-sectional view schematically showing a configuration of a polishing apparatus according to Embodiment 4 of the present invention, and FIG. 5B is a plan view thereof.

This embodiment is different from the first and second embodiments in that an outer wall 508 is provided in the casing 509 of the top ring 107, and the other components are the same. Detailed description will be omitted.

That is, as shown in FIG. 5, the polishing pad 102 is attached to the upper surface of the turntable 101 as in the first embodiment, and the slurry supply pipe 103 and the semiconductor wafer 106 are sucked and held on the turntable 101. A top ring 107 is disposed, and an annular retainer ring 104 for locking the semiconductor wafer 106 is provided on the lower end surface of the top ring 107.

Similar to the first embodiment, the outer wall 508 is configured in a plane U shape having a curved portion 508a and a support portion 508b extending from the end of the curved portion 508a. The curved portion 508a is disposed so as to surround a part of the outer peripheral surface of the top ring 107, and the support portion 508b is fixed to the casing 509 of the top ring via the elastic body 114. The elastic body 114 presses the curved portion 508 a of the outer wall 508 against the polishing pad 102 with a predetermined pressure.
The polishing process by the polishing apparatus having the above-described structure is the same as that in the first embodiment. First, the curved portion 508a of the outer wall 508 is brought into contact with the surface of the polishing pad 102 with a predetermined pressure, and the polishing surrounded by the curved portion 508a is performed. Slurry is supplied to the region S from the slurry supply pipe 103, and polishing is performed by rotating and rotating the top ring 107 holding the semiconductor wafer 106 to the polishing region S to which the slurry is supplied.

In the polishing apparatus according to this example described above, the slurry is locally supplied only to the polishing region S surrounded by the curved portion 508a of the outer wall 508, as in the first example. This makes it possible to secure the minimum thickness of the slurry layer required for polishing a semiconductor wafer with a small amount of slurry as compared with a normal CMP apparatus, so that the amount of slurry used for polishing can be reduced. The use efficiency of the slurry can be improved.

Further, since the outer wall 508 is a simple structure having a planar U-shape, the outer wall 508 has a simpler structure than the conventional polishing apparatus that achieves an improvement in slurry use efficiency by remodeling the retainer ring structure. Furthermore, since the outer wall 508 is opened at the outer edge of the polishing pad 102, it is possible to sufficiently discharge slurry waste liquid and polishing debris and to always supply unused slurry to the semiconductor wafer. The polishing characteristics can be stabilized.

From the above, according to each embodiment of the present invention, it is possible to provide a polishing apparatus and a polishing method capable of improving the use efficiency of the slurry with a simple structure and preventing the deterioration of the polishing characteristics. It becomes possible.

The present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention.

For example, in each of the embodiments described above, the interval L between both ends of the curved portion is set to ¼ of the length of the entire outer edge of the polishing pad. By adjusting the size of the interval L, the slurry It is also possible to adjust the use efficiency and the replacement efficiency of the. However, the distance L is larger than a certain size so that the top ring and the outer wall do not collide when the semiconductor wafer is overhanged by horizontally moving the top ring to the outer edge of the polishing pad after polishing. It is necessary to.

In addition, the shape of the outer wall in each embodiment is a plane U-shape, but may be a U-shape, for example, as long as it is in contact with the polishing pad and surrounds a part of the outer periphery of the semiconductor wafer. .

Further, in each embodiment, when the slurry gradually adheres to the outer wall, and there is a possibility that the loss of the adhering matter may be caused by the scratch of the wafer to be polished, this adhering matter removing process step is added. Also good. For example, each time a lot of semiconductor wafers are processed, the outer wall is lifted from the polishing pad and washed with a hand shower, or a mechanism capable of automatically performing such washing may be added. Good.

Further, the above embodiments may be combined. For example, Example 3 may be combined with Examples 1, 2, and 4, and Example 2 may be combined with Example 4.

Schematic which shows the structure of the grinding | polishing apparatus which concerns on Example 1 of this invention. Schematic which shows the structure of the grinding | polishing apparatus which concerns on the modification of Example 1 of this invention. Schematic which shows the structure of the grinding | polishing apparatus which concerns on Example 2 of this invention. Schematic which shows the structure of the grinding | polishing apparatus which concerns on Example 3 of this invention. Schematic which shows the structure of the grinding | polishing apparatus which concerns on Example 4 of this invention.

Explanation of symbols

101 ... turntable 102 ... polishing pad 103 ... slurry supply tube 104 ... retainer ring 105 ... slurry 106 ... semiconductor wafer 107 ... top ring 108, 208, 308, 408, 508 ... Outer walls 108a, 208a, 308a, 408a, 508a ... Bending portions 108b, 208b, 308b, 408b, 508b ... Supporting portion 114 ... Elastic body 315 ... Slit 417 ... Temperature Adjusted water 509 ... Top ring casing

Claims (7)

A turntable to which a polishing pad is attached;
A top ring for holding a semiconductor wafer and pressing the semiconductor wafer onto the polishing pad;
Enclosing a part of the outer periphery of the semiconductor wafer, and an outer peripheral wall contacting the polishing pad;
A slurry supply pipe for supplying slurry onto the polishing pad region between the outer periphery of the semiconductor wafer and the outer wall;
A polishing apparatus comprising: The top ring has a retainer ring that surrounds the outer periphery of the semiconductor wafer,
The polishing apparatus according to claim 1, wherein the outer surrounding wall surrounds a part of the outer periphery of the semiconductor wafer outside the retainer ring. The polishing apparatus according to claim 1, wherein the outer wall is pressed onto the polishing pad by an elastic body. The polishing apparatus according to claim 1, wherein the slurry is supplied to a position closer to the center of the polishing pad than the top ring. The polishing apparatus according to claim 1, wherein the outer wall has a hollow portion to which a fluid having a temperature different from that of the outer wall is supplied. The polishing apparatus according to claim 1, wherein the outer wall includes a slit. Contacting the outer wall on the polishing pad affixed to the turntable;
Supplying slurry to the polishing pad region surrounded by the outer wall;
Pressing the semiconductor wafer held on the top ring to the polishing pad region to which the slurry is supplied; and
A polishing method comprising:

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