KR20040078361A - Polishing pad conditioner in chemical mechanical polishing apparatus - Google Patents

Abstract

PURPOSE: A polishing pad conditioner for CMP apparatus is provided to perform a uniform conditioning operation on all regions of a polishing pad by controlling differently the operating force of a diamond disk on the polishing pad according to the radius direction of the polishing pad. CONSTITUTION: A diamond disk(41) is used for regenerating a surface of a polishing pad. The diamond disk is moved along the radius direction of the polishing pad in order to polish the polishing pad. A diamond disk holder(42) is used for supporting the diamond disk and is moved to upper and lower directions. The first and the second driving sources(43,45) are used for providing the driving force to the diamond disk in order to move the diamond disk to the upper and the lower directions.

Description

Polishing pad conditioner in chemical mechanical polishing apparatus

TECHNICAL FIELD The present invention relates to a chemical mechanical polishing apparatus, and more particularly, to a polishing pad conditioner for regenerating a polishing pad surface.

As is well known, the chemical mechanical polishing (CMP) process is a planarization process in which a chemical reaction by a slurry and mechanical processing by a polishing pad are simultaneously performed.

This CMP process can obtain global planarization compared to the reflow or etch-back process that has been used for surface planarization, and has the advantage of being able to be performed at low temperatures.

In addition, the CMP process is proposed for surface planarization, but recently, due to the high integration of semiconductor devices, polysilicon in trench embedded oxide etching and self-aligned contact processes in a STI (Shallown Trench Isolation) process It is used in metal film etching processes in film etching and metal wiring processes, and its field of use is gradually expanding.

Hereinafter, an apparatus (hereinafter, referred to as a CMP apparatus) used in the CMP process will be briefly described.

1 and 2 are plan and cross-sectional views of a typical CMP apparatus. As shown, the conventional CMP apparatus presses a platen (1) on which a polishing pad (2) is attached on a surface, and presses the wafer (10) placed on the platen (1) at a predetermined pressure. Conditioner (6) comprising a polishing head (3), a slurry supply nozzle (4) for spraying slurry (8) on the platen (1), and a diamond disk (5) as a part for regenerating the polishing pad surface It consists of.

According to this CMP apparatus, after the wafer 10 is placed on the platen 1 in a state of being laid down by the polishing head 3, the slurry supply nozzle 4 from the platen 1, more precisely, In this state, the slurry 8 is sprayed on the polishing pad 2, and in this state, the wafer 10 is rotated in accordance with the rotation of the polishing head 3, and at the same time, the platen 1 is rotated. Polishing) is carried out.

The conditioner 6 also regenerates the polishing pad 2 in such a manner as to reciprocate in the radial direction of the polishing pad 2 while pressing the diamond disk 5 at a predetermined pressure on the polishing pad 2. That is, conditioning is performed.

However, according to the conventional CMP apparatus described above, as shown in FIG. 3, the polishing pad 6 having the diamond disk 5 is conditioned while the conditioner 6 reciprocates one cycle along the radial direction of the polishing pad 2. (2) shows that the diamond disk 5 of the conditioner 6 moving at a constant speed in relation to the rotational speed being different for each radial position of the polishing pad 2 has a different time for each pad position. For example, conditioning time is reduced toward the edge of the polishing pad. Accordingly, the polishing pad 2 having completed the conditioning has a different cross-sectional thickness for each position. That is, poor conditioning occurs.

As a result, the wafer also undergoes polishing unevenness as CMP is performed on the wafer using a non-uniformly conditioned polishing pad, resulting in a decrease in device reliability and production yield.

Accordingly, an object of the present invention is to provide a polishing pad conditioner of a CMP apparatus that can be uniformly conditioned over the entire area of the polishing pad, which is devised to solve the above problems.

It is another object of the present invention to provide a polishing pad conditioner of a CMP apparatus capable of preventing wafer polishing irregularity through uniform conditioning of the polishing pad.

1 and 2 are a plan view and a cross-sectional view showing a conventional chemical mechanical polishing device.

3 is a view for explaining a polishing pad cross-sectional thickness relationship according to the polishing pad radial position after conditioning using a conventional polishing pad conditioner.

Figure 4 is a cross-sectional view showing a polishing pad conditioner of the chemical mechanical polishing apparatus according to the present invention.

5 is a view for explaining a polishing pad cross-sectional thickness relationship according to the polishing pad radial position after polishing pad conditioning using a polishing pad conditioner according to the present invention.

6 is a control block diagram of a polishing pad conditioner according to the present invention;

Explanation of symbols on the main parts of the drawings

41: diamond disc 42: diamond disc holder

43: pneumatic 44: electromagnet coil

45: electromagnet force 46: coil flux

50: polishing pad 61: force profile generator

62 controller 63 driver

64 pressure sensor 65 pressure / force transducer

In order to achieve the above object, the present invention is provided to regenerate the polishing pad surface in the CMP apparatus for polishing the wafer through the chemical reaction by the slurry and the mechanical processing by the polishing pad, the radial direction of the polishing pad A diamond disk for polishing the polishing pad while reciprocating along the diamond disk, a diamond disk holder configured to support the diamond disk and to move up and down, and to generate a force acting downward and upward with respect to the diamond disk, respectively. A polishing pad conditioner of a CMP apparatus, comprising a first and a second driving source such that the force acting on the polishing pad by the diamond disk is different depending on the radial position of the polishing pad.

The polishing pad conditioner of the CMP apparatus according to the present invention includes a controller for controlling the drive source, a pressure sensor for sensing a pressure applied to the polishing pad from the diamond disk, and a pressure value obtained from the pressure sensor. The apparatus further includes a pressure / force converter for converting and inputting the controller.

The polishing pad conditioner of the CMP apparatus according to the present invention further includes a force profile generator for generating and inputting a force profile to the controller according to the process conditions, wherein the force profile is polished with respect to the radial direction of the polishing pad. It is inversely proportional to the profile of the conditioning time per unit area of the pad.

In the polishing pad conditioner of the CMP apparatus according to the present invention, the first driving source for generating the downward force is a pneumatic pressure having a low control response speed, and the second driving source for generating the upward force has a control response speed. It is fast electromagnetism. The electromagnet force is generated by the path of the coil magnetic flux generated by applying a current to the electromagnet coil. The downwardly acting force is kept constant, and the upwardly acting force is adjusted to be different depending on the position of the polishing pad.

According to the present invention, since the force exerted on the polishing pad by the diamond disc is controlled, even though the rotational speed is different in the radial direction of the polishing pad, it is possible to achieve uniform conditioning over the entire area of the polishing pad.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a cross-sectional view showing a polishing pad conditioner in the CMP apparatus according to the present invention, Figure 5 is a view illustrating a polishing pad cross-sectional thickness relationship according to the polishing pad radial position after conditioning using the polishing pad conditioner according to the present invention 6 is a control block diagram of a polishing pad conditioner according to the present invention.

Referring to Figure 4, the polishing pad conditioner of the present invention to hold the diamond disk 41 and the diamond disk 41 so as to be able to move up and down by the pneumatic 43 in the downward direction and the electromagnet force 45 in the upward direction. Configured diamond disk holder 42 and electromagnet coil 44 which is one of the means for generating the upward force. At this time, the electromagnet force 44 is generated by the path of the coil magnetic flux 46 generated by applying a current to the electromagnet coil 44, therefore, the diamond disc holder 42 is made of a magnetic material desirable.

Here, in the embodiment of the present invention, as the driving source for generating the force acting in the downward direction and the upward direction, respectively, the pneumatic pressure and the electromagnet force with the high control response speed are used, but other drivers can be used. have.

According to the polishing pad conditioner of the present invention having the configuration as described above, the diamond disk is reciprocating at a constant speed with respect to the radial direction of the polishing pad, in this process the diamond disk is pressed against the polishing pad, that is, And conditioning the polishing pad with a profile of the force minus the upward electromagnet force from the downward pneumatic force.

Here, the diamond disk pressing force of the polishing pad is composed of a pneumatic force which is a downward force by a constant pneumatic force and an electromagnet force that is an upward force by an electromagnet coil, wherein the pneumatic pressure acts as a constant force regardless of the position of the polishing pad. On the other hand, the electromagnet force acts as a force that changes depending on the position of the polishing pad through the control of the current applied to the electromagnet coil.

Therefore, the force that the diamond disk presses on the polishing pad is proportional to the thickness of the polishing pad polished by the conditioner. In the polishing pad conditioner of the present invention, as shown in FIG. By controlling the pressing force of 50, the cross-sectional thickness of the conditioned polishing pad 50 can be made uniform over the entire area even though the rotational speed for each position of the polishing pad 50 is different.

That is, the polishing pad conditioner of the present invention controls the conditioning speed and pressure to be different according to the radial position of the polishing pad, and at the same time makes the conditioning time per pad unit area different, thereby making it possible to cross the pad cross section over the entire area of the polishing pad 50. It can be conditioned to be uniform in thickness.

On the other hand, the polishing pad conditioner according to the present invention described above, to control the conditioning time per unit area of the polishing pad, as shown in Figure 6, the controller 62 for controlling the drive source such as pneumatic and electromagnet force, and diamond A pressure sensor 64 for sensing the pressure applied to the polishing pad from the disk, and a pressure / force converter 65 for converting the pressure value obtained from the pressure sensor 64 into force and re-entering the controller 62. It includes.

In addition, the polishing pad conditioner of the present invention further includes a force profile generator 61 which generates and inputs a force profile to the controller 62 according to the process conditions. In this case, the force profile may be understood as being inversely proportional to the profile of the conditioning time per unit area of the polishing pad relative to the radial direction of the polishing pad.

As a result, in the polishing pad conditioner of the present invention, the profile of the force on which the diamond disc presses the polishing pad is generated by the force profile generator 61 when the rotational speed of the polishing pad is determined under the polishing conditions of each process. When the optimum force profile is generated by the generator 61, the control value is inputted by the conditioner controller 62 to the electromagnet coil 63, which is the driver of the upward force, along the profile, and the pressure provided to the driver. The pressure is sensed by the sense line 64 and the force pressed by the diamond disc at each polishing pad position by the pressure / force transducer 65 is re-entered into the controller 62.

By conditioning the polishing pad with the optimal force profile in this order, the cross-sectional thickness of the conditioned polishing pad is equal to the polishing pad even if the conditioning time per unit area varies with respect to the inner and outer circumference when the conditioner reciprocates on the polishing pad at a constant speed. It can be made constant regardless of the position of.

In the above, conditioning on the polishing pad may be performed simultaneously with the wafer polishing process, or may be performed before the wafer polishing process.

As described above, the present invention can control the force applied to the polishing pad so that the diamond disk is different from one position to another in the radial direction of the polishing pad so that uniform conditioning can be made over the entire area of the polishing pad. Polishing uniformity to the wafer can be increased.

On the other hand, since the embodiments of the present invention described above are for the purpose of illustration, various modifications, changes, and additions will be possible to those skilled in the art within the spirit and scope of the present invention, and therefore, such modifications and changes are claimed It should be seen as belonging to a range.

Claims (8)

In the chemical mechanical polishing apparatus for polishing a wafer through a chemical reaction by a slurry and a mechanical processing by a polishing pad, the polishing pad is provided to regenerate the polishing pad surface, and the polishing pad is polished while reciprocating along the radial direction of the polishing pad. A diamond disc comprising a diamond disc, a diamond disc holder configured to support the diamond disc and capable of vertical movement, and first and second driving sources generating forces acting downward and upward with respect to the diamond disc, respectively And a force acting on the polishing pad according to a radial position of the polishing pad. According to claim 1, wherein the controller for controlling the drive source, a pressure sensor for sensing the pressure applied to the polishing pad from the diamond disk, and converts the pressure value obtained from the pressure sensor into a force to input to the controller A polishing pad conditioner of a chemical mechanical polishing device, further comprising a pressure / force transducer. 3. The polishing pad conditioner of claim 2, further comprising a force profile generator for generating and inputting a force profile to the controller according to process conditions. 4. The polishing pad conditioner of claim 3, wherein the force profile is inversely proportional to the profile of conditioning time per unit area of the polishing pad relative to the radial direction of the polishing pad. 2. The polishing pad conditioner of claim 1, wherein the first driving source generating the downward force is pneumatic with a low control response speed. 2. The polishing pad conditioner of claim 1, wherein the second driving source generating the upward force is an electromagnet force having a fast control response speed. 7. The polishing pad conditioner of claim 6, wherein the electromagnet force is generated by a path of a coil flux generated by applying a current to the electromagnet coil. The polishing pad conditioner of claim 1, wherein the downwardly acting force is kept constant and the upwardly acting force is adjusted to be different according to the position of the polishing pad.