JP3104164B2 - Polishing equipment for semiconductor wafers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a semiconductor wafer, and more particularly to a CMP (Chemical-Mechano-Polishing) for chemically polishing the surface of a semiconductor wafer or glass.
Related to the device.

[0002]

2. Description of the Related Art A CMP apparatus used in a polishing apparatus for a semiconductor wafer uses softer particles than the semiconductor wafer as polishing particles, causes a solid-phase reaction between the particles and the semiconductor wafer, and causes a contact interface between the two. Is a device that generates a foreign substance by the above reaction and performs polishing while removing the portion, and has the advantage of high mirror finish and little processing deterioration.

Such a CMP apparatus includes a polishing cloth and a suction table for holding the semiconductor wafer by suction. The semiconductor table is pressed against the polishing cloth by the suction table, and the polishing cloth and the suction table are rotated or rotated relative to each other. Revolve and polish the surface of the semiconductor wafer.

[0004]

However, in the conventional CMP apparatus, the moving distance of any point on the semiconductor wafer is, for example, away from the center of rotation because the suction table only rotates or revolves and the polishing pad only rotates. There is a disadvantage that it becomes longer according to. Thereby, the conventional CMP
The apparatus has a drawback in that the polishing amount of the semiconductor wafer is not constant at each portion in the semiconductor wafer surface and the flatness is deteriorated.

[0005] Such a problem can be solved by increasing the relative rotation speed between the suction table and the polishing cloth and increasing the contact distance per hour of the semiconductor wafer with the polishing cloth. There is a disadvantage that the semiconductor wafer is broken during polishing. The present invention has been made in view of such circumstances, and provides a semiconductor wafer polishing apparatus capable of improving the flatness of a semiconductor wafer without increasing the relative rotation speed between the suction table and the polishing pad. With the goal.

[0006]

According to the present invention, in order to achieve the above object, a semiconductor wafer is pressed against a polishing cloth while being suction-held on a suction table, and the suction table and the polishing cloth are relatively rotated. In a semiconductor wafer polishing apparatus for polishing a semiconductor wafer, a vibration generating means for vibrating the suction table or the polishing cloth in a surface direction of the semiconductor wafer is provided, and the vibration generating means is driven. Rutotomoni vibrate the suction table or polishing cloth, this vibration
Attenuated to a predetermined frequency by a spring, the polishing cloth is rotated around the axis of the rotating shaft, and the polishing cloth is revolved around an axis eccentric to the axis of the rotating shaft. The method is characterized by polishing a semiconductor wafer.

According to the present invention, the suction table and the polishing pad are relatively rotated, and the polishing pad is rotated and revolved.
Allowed, and, depending Rutotomoni to vibrate the suction table or polishing cloth by driving the vibration generating means, a vibrating motion to the spring
The semiconductor wafer is polished while being attenuated to a predetermined frequency . As a result, in the present invention, the contact distance per unit time of the semiconductor wafer with the polishing pad becomes longer by the length of the vibration component, so that the polishing rate is improved. In addition, the relative contact distance between the semiconductor wafer and the polishing pad is instantaneously observed, and the amount of movement due to rotation is negligible due to vibration due to vibration components. Therefore, in the present invention, since the polishing amount of the semiconductor wafer is constant, the flatness of the semiconductor wafer can be improved without increasing the relative rotation speed between the suction table and the polishing pad.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a semiconductor wafer polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a main part structural diagram of a CMP apparatus to which a semiconductor wafer polishing apparatus according to an embodiment of the present invention is applied. The CMP apparatus 10 shown in FIG.
And a suction table 14. A semiconductor wafer 16 is held by suction on the lower surface of the suction table 14 with its polished surface facing downward.

The polishing cloth 12 has a motor 18 at the lower center.
Of the rotating shaft 20 is fixed at a predetermined speed around the axis 20A of the rotating shaft 20 by the rotating force of the motor 18 in the direction indicated by the arrow in the figure. The rotating shaft 20 includes a bearing 2
A driven pulley 24 is rotatably provided via the second pulley 24. The rotary shaft 20 is inserted and arranged at a position eccentric with respect to the axis 24A of the driven pulley 24. The driven pulley 24
The lower flange 25 is provided on the apparatus main body 10A via a bearing 26 so as to be rotatable about its axis 24A. The driven pulley 24 is wound around a driving pulley 30 via a belt 28, and an output shaft 33 of a driving motor 32 is fixed to the driving pulley 30.
Therefore, when the driving force of the driving motor 32 is transmitted to the driven pulley 24 via the driving pulley 30 and the belt 28,
The driven pulley 24 rotates about its axis 24A, and the rotating shaft 20 revolves around the axis 24A following the rotation of the driven pulley 24, so that the polishing pad 12 revolves about the axis 24A.
The motor 18 is mounted at an eccentric position of a rotary plate 36 provided on the apparatus main body 10A via a bearing 34, and revolves following the revolution of the polishing pad 12.

A rotary shaft 38 of a motor (not shown) is fixed to the upper central portion of the suction table 14, and the suction table 14 is rotated at a predetermined speed in a direction indicated by an arrow in FIG. Further, a rod of an air cylinder (not shown) is fixed to the upper part of the motor, and the motor and the suction table 14 are moved up and down by the expansion and contraction of the rod.

Accordingly, the semiconductor wafer 16 is pressed against the surface 12A of the polishing pad 12 by the downward movement of the suction table 14 due to the extension operation of the rod. Then, the semiconductor wafer 16 is polished to a polishing amount target value by rotating and revolving the polishing pad 12 and rotating the suction table 14. During polishing, a slurry (not shown) is supplied between the polishing pad 12 and the semiconductor wafer 16.

Meanwhile, a tray-like holder 40 is fixed to the upper surface of the suction table 14 with its open part facing downward. The holder 40 has an opening 40A formed in the upper central portion, and the rotating shaft 38 is disposed through the opening 40A. The holder 40 is rotated together with the suction table 14 by the rotation of the rotating shaft 38. As shown in FIGS. 1 and 2, a piezo element (vibration generating means) 42 and two springs 44, 4 are provided between the holder 40 and the suction table 14.
4 are arranged. The piezo element 42 is arranged so that its distortion direction indicated by an arrow in the drawing is parallel to the surface of the semiconductor wafer 16, and the flange of the holder 40 is oriented such that the distortion direction is directed to the center 14 A of the suction table 14. The portion 41 and the side surface of the suction table 14 are fixed. The piezo element 42 is connected to the drive section 46 shown in FIG. 1 and is distorted in the above direction when a voltage is applied from the drive section 46. The driving section 46 is controlled by a control section (not shown) so that the piezo element 42 is intermittently distorted at high speed. Therefore, when the piezo element 42 is driven,
The suction table 14 is vibrated in the surface direction of the semiconductor wafer 16.

As shown in FIG. 2, the springs 44 are provided between the flange 41 of the holder 40 and the suction table 14.
And an extension line L1 of a line segment L1 connecting the piezo element 42 and the center 14A of the suction table 14.
2 are symmetrically arranged. These springs 44, 44 move from the piezo element 42 to the suction table 1.
The vibration given to 4 is attenuated to a predetermined frequency.

Next, the operation of the semiconductor wafer polishing apparatus configured as described above will be described. First, the suction table 14 is moved upward by a predetermined amount, and the semiconductor wafer 16
Is held on the suction table 14 by suction. Next, the suction table 14 is moved downward to move the semiconductor wafer 16 to the polishing cloth 1.
2 against the surface 12A. Next, the suction pad 14 is rotated while rotating and revolving the polishing cloth 12,
Then, the semiconductor wafer 16 is polished while driving the piezo element 42 to vibrate the suction table 14.

During the polishing, as shown in FIG. 3A, a movement locus 48 of an arbitrary point A on the semiconductor wafer 16 is obtained.
Is obtained by adding the movement of the vibration component by the piezo element 42 to the relative rotational movement of the polishing pad 12 and the suction table 14, so that the trajectory moves in an arc while moving in a zigzag. On the other hand, in a conventional polishing apparatus for polishing a semiconductor wafer only by the relative rotation between the polishing pad and the suction table, as shown in FIG. It becomes a circular locus.

Therefore, in the present embodiment, the contact distance per hour of the semiconductor wafer 16 with the polishing pad 12 is
Since the length is longer by the length of the vibration component than in the conventional apparatus, the polishing rate can be improved. Further, in the present embodiment, the relative contact distance between the semiconductor wafer 16 and the polishing pad 12 due to the vibration component is equal at all points in the semiconductor wafer surface, so that the polishing amount is constant.

Therefore, in the present embodiment, the flatness of the semiconductor wafer 16 can be improved without increasing the relative rotation speed between the suction table 14 and the polishing pad 12. In the present embodiment, the semiconductor wafer 1 is used as a work.
Although 6 was applied, a sheet glass may be applied instead. In the present embodiment, the suction table 14 is vibrated. However, the polishing cloth 12 may be vibrated, or both the suction table 14 and the polishing cloth 12 may be vibrated.

Further, in the present embodiment, the piezo element 42 is applied as the vibration generating means. However, the present invention is not limited to this. .

[0019]

As described above, according to the semiconductor wafer polishing apparatus of the present invention, the suction table and the polishing pad are relatively rotated, and the polishing pad is rotated and revolved.
And drive the vibration generating means to
Vibrates the polishing cloth, and the vibration is
Therefore, the semiconductor wafer is polished while being attenuated to a predetermined frequency , so that the flatness of the semiconductor wafer can be improved without increasing the relative rotation speed between the suction table and the polishing pad.

[Brief description of the drawings]

FIG. 1 is a main part structural view of a CMP apparatus to which a semiconductor wafer polishing apparatus of the present invention is applied.

FIG. 2 is an explanatory view showing the arrangement positions of a piezo element and a spring.

FIG. 3 is a comparative explanatory diagram showing a movement locus of an arbitrary point A in a semiconductor wafer surface;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... CMP apparatus 12 ... Abrasive cloth 14 ... Suction table 16 ... Semiconductor wafer 18, 32 ... Motor 40 ... Holder 42 ... Piezo element 44 ... Spring 46 ... Drive part

Continuation of the front page (56) References JP-A-7-299732 (JP, A) JP-A-6-21029 (JP, A) JP-A-58-202768 (JP, A) JP-A-59-53159 (JP) , A) Fully open sho 59-173551 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24B 37/00 B24B 37/04 H01L 21/304 621 H01L 21/304 622

Claims (1)

(57) [Claims] 1. A semiconductor wafer polishing apparatus for polishing a semiconductor wafer by pressing a semiconductor wafer against a polishing cloth while holding the semiconductor wafer on a suction table and rotating the suction table and the polishing cloth relative to each other. vibration generating means for vibrating the suction table or the polishing pad in the surface direction of the semiconductor wafer is provided, when by driving the vibration generating means Ru vibrate the suction table or polishing cloth
In both cases, the vibration is damped to a specified frequency by a spring
Then, the polishing cloth is rotated about the axis of the rotating shaft, and the semiconductor wafer is polished by revolving the polishing cloth about the axis eccentric to the axis of the rotating shaft. Semiconductor wafer polishing apparatus.