JP2002370159A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device capable of reducing a consumption amount of abrasive liquid and capable of uniformly polishing substrates being a polishing object. SOLUTION: In a polishing device comprising a turn table 12 having an abrasive surface 11; a top ring 14 to hold a substrate, being a polishing object, and pressing it against the abrasive surface 11 of the polishing table 12; and a nozzle 20 through which grinding liquid is fed to the abrasive surface 11, the polishing device is provided with the nozzle 20 which is movable from a center C of the abrasive surface of the turn table 12 toward an outer peripheral part and through which grinding liquid is fed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for polishing a substrate such as a semiconductor wafer in a flat and mirror-like manner, and more particularly, to a turntable having a polished surface, and holding and pressing a substrate to be polished against the polished surface. Top ring
The present invention relates to a polishing apparatus having a nozzle for supplying a polishing liquid to the polishing surface.

[0002]

2. Description of the Related Art In recent years, as the degree of integration of semiconductor devices has increased, circuit wiring has become finer, and the distance between wirings has become smaller. In particular, in the case of optical lithography having a very narrow line width, the allowable depth of focus becomes shallow, so that a high flatness of the image forming surface of the stepper is required. Therefore, it is necessary to planarize the surface of the semiconductor wafer. As one of the planarization methods, chemical mechanical polishing (CMP) is performed using a polishing apparatus.

As the polishing apparatus, there is known a polishing apparatus which includes a top ring for holding a semiconductor wafer with respect to a rotating polishing table, and performs polishing by pressing the semiconductor wafer against a polishing surface. An example of the configuration of the polishing apparatus will be described with reference to FIG.
This polishing apparatus includes a turntable 42 having a polishing pad 40 adhered on the upper surface thereof, a top ring 44 for holding a semiconductor wafer W to be polished in a rotatable and pressable manner, and a polishing agent for supplying a polishing liquid Q to the polishing pad 40. A liquid supply nozzle 46 is provided. The top ring 44 is connected to a top ring shaft 48, and is supported by an air cylinder (not shown) so as to be vertically movable.

The top ring 44 is provided with an elastic mat 50 made of polyurethane or the like on the lower surface thereof.
The semiconductor wafer W is held in close contact with the semiconductor wafer W. Further, the top ring 44 is provided with a cylindrical guide ring 52 on the outer peripheral edge thereof so that the semiconductor wafer W does not come off from the lower surface of the top ring 44 during polishing. The guide ring 52 is fixed to the top ring 44, and its lower end surface protrudes from the holding surface of the top ring 44, and holds a semiconductor wafer W to be polished in a concave portion inside the guide ring 52. .

With this configuration, the semiconductor wafer W is held under the elastic mat 50 on the lower surface of the top ring 44, and the semiconductor wafer W is pressed against the polishing pad 40 on the turntable 42 by the top ring 44.
The polishing is performed by rotating the turntable 42 and the top ring 44 so that the polishing pad 40 and the semiconductor wafer W move relative to each other. At this time, the polishing liquid Q is supplied onto the polishing pad 40 from the polishing liquid supply nozzle 46. The polishing liquid is, for example, a suspension of abrasive grains made of fine particles such as silica in an alkaline solution. The semiconductor wafer W is formed by a combined action of a chemical polishing action using alkali and a mechanical polishing action using abrasive grains. Polish.

[0006]

As shown in FIG. 2, in a conventional polishing apparatus, a supply nozzle for a polishing abrasive Q is generally disposed substantially above a central portion of a turntable. Was. However, the polishing of the substrate to be polished actually proceeds not at the center of the turntable, but at an intermediate portion between the center of the turntable and the outer periphery. For this reason, when the polishing liquid is dropped onto the center of the turntable, it takes time for the slurry to spread over the surface to be polished of the semiconductor wafer held by the top ring, and therefore the polishing liquid is consumed excessively. There was a problem.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a polishing apparatus capable of reducing the consumption of a polishing slurry and uniformly polishing a substrate to be polished.

[0008]

To achieve the above object, a first aspect of the present invention is a turntable having a polishing surface, and a top ring for holding a substrate to be polished and pressing the substrate against the polishing surface. And a polishing apparatus provided with a nozzle for supplying a polishing liquid to the polishing surface, comprising a nozzle for supplying a movable polishing liquid from the center of the polishing surface of the turntable toward the outer peripheral portion. It is a polishing apparatus.

Here, it is preferable that the nozzle supplies the polishing liquid to the polishing surface at a substantially intermediate position from the center to the outer periphery of the polishing surface. Further, it is preferable that the nozzle is supported by an arm, and the arm has a fulcrum outside the turntable, and is rotatable around the fulcrum.

In a second aspect of the present invention, a substrate to be polished is held by a top ring and pressed against the polishing surface to rotate while supplying a polishing slurry to the polishing surface of the rotating turntable. In the polishing method for advancing the polishing, the polishing is performed while the polishing liquid is supplied from a nozzle substantially in the middle from the center to the outer periphery of the polishing surface of the turntable.

According to the present invention, since the nozzle for supplying the polishing liquid which is movable from the center of the polishing surface of the turntable to the outer peripheral portion is provided, the portion where the substrate to be polished held by the top ring exists is provided. The polishing liquid can be efficiently dropped. This makes it possible to reduce the time required for the polishing slurry to reach the most effective portion for polishing the substrate to be polished,
Slurry consumption can be reduced. In addition, since the polishing liquid is supplied to the portion most effective for polishing, the substrate to be polished can be uniformly polished.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a polishing apparatus according to the present invention will be described below with reference to FIG.

FIG. 1 is a plan view showing the overall configuration of the polishing apparatus. As shown in FIG. 1, in this polishing apparatus, a turntable 12 provided with a polishing pad 11 is rotated about a center C thereof by a drive mechanism (not shown). The polishing pad 11 is made of, for example, a nonwoven fabric such as Politex manufactured by Rodale or urethane foam such as IC1000, and is supplied with a polishing abrasive to constitute a polishing surface.

The semiconductor wafer W to be polished is held by the top ring 14, pressed against the polishing surface 11 of the turntable which is rotated by a rotation pressing mechanism (not shown), and rotated, whereby polishing proceeds. That is, top ring 1
4 presses the semiconductor wafer W against the polishing surface 11 while rotating about its center 14c. The top ring 14 is held by an arm 15 and is rotatable about a shaft 16. The top ring 14 sends the polished semiconductor wafer W to a pusher 17, and holds the unpolished semiconductor wafer W from the pusher 17 to the top ring 14. , And rotate to a predetermined polishing position.

Nozzle 2 for supplying a polishing abrasive to polishing surface 11
0 is held by the arm 21 and reference numerals 20 and (20)
It is possible to slide between and. For this reason, the supply position of the polishing abrasive liquid is slid from the center C of the polishing surface 11 to the intermediate portion D reaching the outer peripheral portion in the radial direction,
It has a structure that can be fixed at any place. Here, the intermediate portion D is a substantially intermediate portion between the center C of the polishing surface 11 and the outer peripheral portion. This intermediate portion D is also a portion passing through the center 14c of the semiconductor wafer W to be polished. Therefore, the polishing liquid supplied from the polishing liquid supply nozzle located at the intermediate portion D is efficiently rotated around the central portion 14c of the semiconductor wafer W by the rotation of the turntable 12, as shown by the arrow F in the figure. Supplied.

The distal end of the arm 21 is provided with a nozzle 25 for supplying pure water to the polishing surface 11 at the time of dressing described later. The arm 21 provided with the abrasive liquid supply nozzle 20 and the pure water supply nozzle 25 is rotatable about a shaft 23. That is, as shown in FIG.
It is possible to move to the retreat position outside the device during a test operation or during maintenance. Also, the arm 21
The pure water and the polishing liquid can be supplied to an arbitrary position in the radial direction of the polishing surface 11 by the rotation mechanism.

The dresser 27 is, for example, a diamond dresser, and sharpens and regenerates the polishing surface by pressing the rotating polishing surface 11. Dresser 27 is arm 2
8 is pressed against the polishing surface 11 by a pressing mechanism (not shown). The arm 28 is rotatable about an axis 29 and moves the dresser to the cleaning device 30 as needed. The cleaning device 30 includes a cleaning water spraying mechanism and the like, and cleans the dressing surface of the dresser 27 that has moved to regenerate the dressing function.

Next, a polishing operation using the polishing apparatus will be described. First, the arm 15 provided with the top ring 14 moves to the upper part of the pusher 17, and holds the semiconductor wafer W placed on the pusher 17 by vacuum suction or the like. Then, the arm 15 rotates about the shaft 16 and moves to the polishing position above the intermediate portion D. On the other hand, the turntable 12 is continuously rotating. The polishing supply nozzle 20 is located at the intermediate portion D, and supplies the polishing liquid to the polishing surface 11. Here, the polishing liquid is a slurry in which fine particles of silica or the like are suspended in an alkaline solution or the like, as described above.

Therefore, the polishing liquid supplied to the polishing surface 11 spreads radially inward and outward from the intermediate portion D,
By the rotation of the turntable 12, it is supplied to the lower part of the top ring 14 in the shortest distance according to the arrow F. Then, while rotating the top ring 14, the arm 15 is lowered and the surface to be polished of the semiconductor wafer W is
Pressing to 1 advances polishing. As described above, since the polishing liquid is supplied around the substantially central portion of the semiconductor wafer to be polished, the polishing liquid is efficiently used for polishing.

After the polishing of the predetermined thickness is completed, the semiconductor wafer W is separated from the polished surface, moved and moved by the pusher 17.
Is returned to. Then, if necessary, the dresser 27 is pressed against the polishing surface 11 to perform required dressing. At this time, pure water is supplied from the nozzle 25 at the tip of the arm 21 and is provided for dressing. The dressing may be performed while polishing the semiconductor wafer.

When the polishing liquid is supplied from the polishing liquid supply nozzle 20, the polishing liquid supply nozzle 20 is slidable on the arm 21 as described above. Accordingly, for example, when it is preferable to supply the abrasive fluid to the radially inner side from the intermediate portion D, the abrasive fluid can be easily moved to that position. Thus, it is possible to supply a preferable polishing liquid according to the state of the object to be polished or the like. Similarly, the arm 21 is connected to the shaft 23
, The abrasive liquid supply nozzle 20 and the pure water supply nozzle 25 can be moved to any position in the radial direction. Even with such an operation, it is possible to supply an optimal polishing abrasive liquid or pure water according to the state of the object to be polished.

Therefore, the time required for the polishing liquid to reach the most effective portion on the turntable can be shortened by the moving mechanism of the polishing liquid supply nozzle, and as a result, the consumption of the polishing liquid can be reduced. be able to. According to the experimental results, it is possible to reduce the consumption amount of the polishing abrasive liquid to about 1/2 compared with the case where the polishing abrasive liquid is supplied to the center portion of the conventional polishing surface. For this reason, the production cost of the polishing step can be reduced. Further, even if the supply position of the polishing liquid is changed to reduce the supply amount, the polishing process of the semiconductor wafer is not adversely affected. That is, the slurry is supplied most abundantly near the center of the substrate to be polished, so that the substrate to be polished can of course be satisfactorily polished.

In the above embodiment, the example in which the polishing liquid supply nozzle and the pure water supply nozzle are provided on the same arm has been described. However, these may be provided separately. Also, the abrasive liquid supply nozzle is not limited to the above-described example, and various forms can be used. Thus, various modifications can be made without departing from the spirit of the present invention.

[0024]

According to the present invention as described above,
By arranging and supplying the nozzle at approximately the middle from the center to the outer periphery of the polishing surface of the turntable, the polishing agent can be efficiently supplied to the polishing surface of the substrate to be polished.
As a result, the consumption of the polishing slurry can be reduced, and the substrate to be polished can be uniformly polished.

[Brief description of the drawings]

FIG. 1 is a plan view of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a main part of a conventional polishing apparatus.

[Explanation of symbols]

 Reference Signs List 11 polishing pad (polishing surface) 12 turntable 14 top ring 17 pusher 20 abrasive liquid supply nozzle 21 arm 25 pure water supply nozzle 27 dresser

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Yagi 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 3C058 AA07 AC04 CA01 CB05 DA12 DA17 4F041 AA06 AB02 AB05 BA21

Claims (4)

[Claims] 1. A polishing apparatus comprising: a turntable having a polishing surface; a top ring for holding a substrate to be polished and pressing against the polishing surface; and a nozzle for supplying a polishing liquid to the polishing surface. A polishing apparatus comprising: a nozzle for supplying a polishing liquid movable from a center of a polishing surface of a table to an outer peripheral portion. 2. The polishing apparatus according to claim 1, wherein the nozzle supplies the polishing liquid to the polishing surface at a substantially intermediate position from the center to the outer periphery of the polishing surface. 3. The nozzle is supported by an arm,
The arm has a fulcrum outside the turntable,
The polishing apparatus according to claim 1, wherein the polishing apparatus is rotatable about the fulcrum. 4. A polishing method in which a substrate to be polished is held by a top ring while a polishing abrasive liquid is supplied to a polishing surface of a rotating turntable, and the substrate is pressed against the polishing surface and rotated to perform polishing. A polishing method, wherein the polishing is performed while the polishing liquid is supplied from a nozzle at a substantially intermediate position from the center to the outer periphery of the polishing surface of the turntable.