JP2008192935A - Slurry supply device of cmp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slurry supply device of a CMP device improved in polishing performance for a wafer by efficiently supplying a necessary amount of slurry to a wafer portion on a polishing pad. <P>SOLUTION: The slurry supply device of the CMP device is constituted such that a dripping position of the slurry S on a polishing pad 6 is set to a predetermined position upstream from a polishing head 3 in a platen rotating direction by fixing a slurry piping 9 transporting the slurry S to a nozzle 11 along a bearing 7 supporting a rotary shaft 8 of a polishing head 3, and by disposing the nozzle 11 at a predetermined position upstream from the polishing head in the platen rotating direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a slurry supply apparatus in a CMP apparatus, and more particularly, to a slurry supply apparatus in a CMP apparatus capable of improving the polishing performance of a wafer in chemical mechanical polishing (CMP). is there.

  The oxide film formed on the semiconductor wafer is subjected to lithography and etching to form a groove pattern corresponding to the wiring pattern, and a conductive film made of Cu or the like for filling the groove pattern is formed thereon, A process for forming a wiring pattern or the like by polishing and removing unnecessary portions of the conductive film by CMP is known. Such polishing of the wafer by CMP is performed by pressing the wafer held by the polishing head against the polishing pad on the rotating platen with a predetermined pressure and supplying slurry to the wafer portion on the polishing pad.

  In the wafer polishing process, various parameters such as the number of rotations of the polishing head and the platen and the pressure on the wafer are combined in order to obtain a required polishing performance. However, the flow of the slurry dropped on the polishing pad changes due to the parameter setting change, and the amount of the slurry supplied to the wafer portion changes accordingly. For this reason, a slipout or the like due to a change in the polished shape of the wafer or insufficient supply of slurry to the wafer portion may occur. In order to prevent these, it is necessary to change the slurry dropping position on the polishing pad according to the set parameters.

  As a related art related to this, for example, the following slurry supply apparatus for a chemical mechanical polishing apparatus is known. In this prior art, a slurry transfer pipe for transferring slurry sent from a slurry supply source, an arm having a base end attached to a polishing table on the side of the platen and holding the slurry transfer pipe, A knob that is rotatably attached to the tip, and a nozzle that is connected to the slurry transfer pipe and supported by the knob and disposed at an upper position near the center of the polishing pad. The position of the nozzle can be adjusted in a circular orbit range centered on the center. By manually turning the knob, the supply position of the slurry is adjusted within a limited range near the center of the polishing pad to improve the polishing profile of the wafer (see, for example, Patent Document 1). ).

As another conventional technique, for example, the following polishing apparatus is known. This prior art includes a fulcrum on the outside of a turntable (platen), and an arm that is rotatable about the fulcrum. A nozzle for supplying abrasive liquid (slurry) is provided at the tip of the arm, and the nozzle is movable from the center of the polishing surface (polishing pad) of the turntable toward the outer periphery by the operation of the arm. . Abrasive liquid is supplied onto the polishing surface substantially in the middle from the center to the outer periphery of the polishing surface by the nozzle. The abrasive liquid supplied from the nozzle is supplied to the semiconductor wafer portion held by the top ring by the rotation of the turntable. Then, the polishing proceeds as the semiconductor wafer is pressed and rotated by the polishing surface of the rotating turntable (see, for example, Patent Document 2).
JP 2004-63888 A (pages 4-6, FIG. 3). JP 2002-370159 (pages 2 to 3, FIG. 1).

  In the prior art described in Patent Document 1, the nozzle for slurry discharge is attached to the knob portion at the tip of the arm and can be adjusted in a limited range near the center of the polishing pad. However, since the nozzle is disposed on the tip side of the arm, the slurry discharge position by the nozzle cannot follow the movement of the wafer due to the oscillation of the polishing head. For this reason, it is difficult to efficiently supply the required amount of slurry to the wafer portion at all times.

  In the prior art described in Patent Document 2, since the nozzle is provided at the tip of the arm having a fulcrum on the outside of the turntable, the slurry discharge position by the nozzle is the same as the above. It is impossible to follow the movement of the wafer due to the swinging of the wafer. For this reason, it is difficult to efficiently supply the required amount of slurry to the wafer portion at all times.

  This will be further described with reference to (a) to (d) of FIG. FIGS. 3A to 3D show the dripping of the slurry onto the polishing pad at every set rotation speed of the platen when the rotation speed of the platen is changed among various parameters in the wafer polishing process. The case where the position is adjusted is described. FIG. 3A shows a case where the dropping position of the slurry S from the nozzle 12 onto the polishing pad 6 is adjusted to the optimum position corresponding to the low-speed rotation with the platen rotation speed set to the low-speed rotation. Show. In FIG. 3B, the adjustment position of the nozzle 12 remains in the state shown in FIG. 3A, and the platen rotation speed is changed to a high-speed rotation according to the progress of the polishing state of the wafer. At this time, the flow of the slurry S on the polishing pad 6 changes. Therefore, in FIG. 3C, the position of the nozzle 12 on the polishing pad 6 is adjusted to the optimum position corresponding to the high speed rotation. At this time, the slurry S on the polishing pad 6 changes to an appropriate flow. FIG. 3D shows a case where the polishing head 3 is moved by rocking or the like in the proper adjustment state shown in FIG. At this time, the position of the nozzle 12 cannot follow the movement of the polishing head 3, that is, the movement of the wafer, and it becomes difficult to supply a required amount of slurry to the wafer portion.

  Therefore, a technical problem to be solved in order to efficiently supply a required amount of slurry to the wafer portion on the polishing pad and improve the polishing performance for the wafer arises, and the present invention solves this problem. For the purpose.

  The present invention has been proposed in order to achieve the above-mentioned object, and the invention according to claim 1 presses a wafer held by a polishing head against a polishing pad on a rotating platen and drops the wafer onto the polishing pad. In a slurry supply apparatus in a CMP apparatus that supplies slurry to a wafer portion on the polishing pad and polishes the wafer, a dropping position of the slurry on the polishing pad is set to a predetermined upstream side of a platen rotation direction with respect to the polishing head. Provided is a slurry supply device in a CMP apparatus set at a position.

  According to this configuration, the slurry is dropped at a predetermined position on the upstream side in the platen rotation direction with respect to the polishing head, so that an appropriate flow of the slurry to the polishing head side is generated on the polishing pad, and a required amount is generated in the wafer portion. A slurry is supplied. Even if the polishing head moves due to rocking or the like, the dropping position of the slurry follows the polishing head while maintaining a predetermined positional relationship. Therefore, even if the polishing head moves, a required amount of slurry is always supplied to the wafer portion.

  According to a second aspect of the present invention, the slurry pipe for transferring the slurry to the nozzle for dropping the slurry is fixed along the bearing supporting the rotating shaft of the polishing head, and the nozzle is upstream of the platen rotation direction with respect to the polishing head. Provided is a slurry supply apparatus in a CMP apparatus which is located at a predetermined position on the side.

  According to this configuration, the slurry pipe is fixed along the bearing supporting the rotating shaft of the polishing head, so that the slurry pipe does not rotate even if the polishing head rotates. Therefore, the positional relationship between the polishing head and the slurry dropping nozzle is always kept constant.

  According to the first aspect of the present invention, the slurry dropping position on the polishing pad is set to a predetermined position upstream of the polishing head in the platen rotation direction. Even when there is a change in parameter settings in the polishing process, the slurry dropping position follows the polishing head while maintaining a predetermined positional relationship. Accordingly, an appropriate flow of the slurry flowing toward the polishing head always occurs on the polishing pad, so that the required amount of slurry can be efficiently supplied to the wafer portion at all times. As a result, the wafer can be accurately polished into a uniform polished shape. Further, since the slurry can be efficiently supplied to the wafer portion, there is an advantage that the amount of the slurry used can be reduced.

  According to a second aspect of the present invention, the slurry pipe for transferring the slurry to the nozzle for dropping the slurry is fixed along the bearing supporting the rotating shaft of the polishing head, and the nozzle is upstream of the platen rotation direction with respect to the polishing head. Therefore, there is an advantage that the positional relationship between the polishing head and the slurry dropping nozzle can always be kept constant.

  In order to achieve the purpose of efficiently supplying the required amount of slurry to the wafer portion on the polishing pad to improve the polishing performance for the wafer, the wafer held by the polishing head is pressed against the polishing pad on the rotating platen In addition, in the slurry supply device in the CMP apparatus for supplying the slurry dropped on the polishing pad to the wafer portion on the polishing pad and polishing the wafer, the dropping position of the slurry on the polishing pad is determined by the polishing head. This is realized by setting a predetermined position on the upstream side of the platen rotation direction with respect to.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a slurry supply device in a CMP apparatus, and FIG. 2 is a diagram for explaining a relationship between a polishing head and a slurry dropping position.

  First, the configuration of the slurry supply apparatus in the CMP apparatus according to the present embodiment will be described. In FIG. 1, a CMP apparatus (chemical mechanical polishing apparatus) 1 is mainly composed of a platen 2 and a polishing head 3. The platen 2 is formed in a disc shape, and a rotating shaft 4 is connected to the center of the lower surface thereof. A polishing pad 6 is attached to the upper surface of the platen 2.

  The polishing head 3 is formed in a disk shape smaller than the platen 2, and a rotary shaft 8 supported by a bearing 7 is connected to the center of the upper surface thereof. The polishing head 3 is driven by a motor (not shown) attached to the rotary shaft 8 and rotates in the direction of arrow B in FIG.

  A slurry pipe 9 for transferring the slurry is fixed to the outer surface portion of the bearing 7 by fixing members 10 and 10 along the bearing 7, and a slurry dropping nozzle 11 is provided at the tip of the slurry pipe 9. Is attached. With this attachment mode, the nozzle 11 is located at a predetermined position upstream of the polishing head 3 in the platen 2 rotation direction.

A wafer (not shown) held by the polishing head 3 is placed and pressed on the upper surface of the polishing pad 6, and the wafer is polished by rotating the platen 2 and the polishing head 3 and supplying slurry from the nozzle 11. . Although the rotation speeds of the platen 2 and the polishing head 3 are different from each other, even if they rotate relative to each other, the wafer polishing is not hindered.

  Next, the operation of the slurry supply apparatus in the CMP apparatus configured as described above will be described with reference to FIGS. Since the slurry pipe 9 is fixed to the bearing 7, even if the polishing head 3 rotates, the slurry pipe 9 does not rotate, and the nozzle 11 is always at a predetermined position upstream of the platen 2 in the rotation direction with respect to the polishing head 3. Located in.

  Therefore, as shown in FIG. 2B, the slurry S is always dripped onto the polishing pad 6 at a predetermined position upstream of the polishing head 3 in the rotation direction of the platen 2. As a result, an appropriate flow for the slurry S to flow toward the polishing head 3 is generated on the polishing pad 6, and a required amount of slurry is supplied to the wafer portion.

  Even if the polishing head 3 moves due to rocking or the like, the positional relationship between the polishing head 3 and the nozzle 11 does not change, and the dropping position of the slurry S always follows the polishing head 3 while maintaining a predetermined positional relationship. Therefore, even if the polishing head 3 moves or the like, the required amount of slurry S is always supplied to the wafer portion.

  Thus, by always supplying the required amount of slurry S to the wafer portion, the wafer is accurately polished into a uniform polishing shape, and problems such as slipout due to insufficient supply of slurry S may occur. There is no.

  Further, a retainer ring (not shown) surrounding the periphery of the wafer is provided on the lower surface of the polishing head 3. A plurality of slurry channels are formed at equal intervals on the lower surface of the retainer ring, while a plurality of grooves (not shown) communicating from the center of the surface portion to the edge portion are formed on the surface portion of the polishing pad 6. In some cases, the slurry S flowing toward the polishing head 3 on the polishing pad 6 is more easily spread over the entire wafer, and the slurry that contributes to polishing including polishing by-products is efficiently removed outside the polishing pad 6. As a result, the wafer is accurately polished into a more uniform polishing shape.

  As described above, in the slurry supply apparatus in the CMP apparatus according to the present embodiment, even when the polishing head 3 is moved due to rocking or the like, or when the parameter setting is changed in the wafer polishing process, the slurry is supplied. The dropping position of S can be made to follow the polishing head 3 while maintaining a predetermined positional relationship.

  An appropriate flow for the slurry S to flow toward the polishing head 3 always occurs on the polishing pad 6, so that the required amount of the slurry S can be efficiently supplied to the wafer portion at all times. Therefore, the wafer can be accurately polished into a uniform polished shape.

  The slurry S can be efficiently supplied to the wafer portion, and the usage amount of the slurry S can be reduced.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The perspective view of the rally supply apparatus in the CMP apparatus which concerns on the Example of this invention. It is a figure which shows the relationship between the polishing head and the dripping position of a slurry in a present Example, (a) is a side view of a polishing head part, (b) is a figure for demonstrating the relationship between the dripping position of a polishing head and a slurry. It is a group diagram for demonstrating adjustment of the slurry dripping position for every setting rotation speed of the platen by the conventional slurry supply apparatus, (a) is a figure which shows the state which adjusted the dripping position of the slurry by low speed rotation, (b) Is a diagram showing a change in slurry flow when adjusted to high speed rotation while adjusting for low speed rotation, (c) is a diagram showing a state in which the dropping position of the slurry is adjusted for high speed rotation, (d) is for high speed rotation The figure which shows the state which a motion produced in the polishing head, adjusting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CMP apparatus 2 Platen 3 Polishing head 4 Rotating shaft 5 Motor 6 Polishing pad 7 Bearing 8 Rotating shaft 9 Slurry piping 10 Fixing member 11 Nozzle 12 Nozzle

Claims (2)

In a slurry supply apparatus in a CMP apparatus for pressing a wafer held by a polishing head against a polishing pad on a rotating platen and supplying slurry dropped onto the polishing pad to a wafer portion on the polishing pad to polish the wafer ,
A slurry supply device in a CMP apparatus, wherein the dropping position of the slurry on the polishing pad is set to a predetermined position upstream of the polishing head in the platen rotation direction. A slurry pipe for transferring the slurry to the nozzle for dropping the slurry is fixed along a bearing that supports the rotating shaft of the polishing head, and the nozzle is positioned at a predetermined position upstream of the polishing head in the platen rotation direction. The slurry supply apparatus in a CMP apparatus according to claim 1.

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