KR20080061939A

KR20080061939A - Chemical mechanical polishing apparatus and method

Info

Publication number: KR20080061939A
Application number: KR1020060137148A
Authority: KR
Inventors: 이원모
Original assignee: 주식회사 하이닉스반도체
Priority date: 2006-12-28
Filing date: 2006-12-28
Publication date: 2008-07-03

Abstract

A chemical mechanical polishing apparatus and a method thereof are provided to extend the life span of a polishing pad by effectively removing residues remaining in a groove through a polishing pad conditioning process. A chemical mechanical polishing apparatus(200) comprises a polishing pad(204), a polishing head(208), a slurry supplying unit(210), and a polishing pad conditioner(212). The polishing pad is fixed to a rotary table and is formed with a groove. The polishing head rotates a semiconductor substrate(206) formed with a thin film to be polished. The slurry supplying unit supplies slurry onto the polishing pad. The polishing pad conditioner adjusts the surface roughness of the polishing pad. The polishing pad conditioner rotates in the first direction for a predetermined time, and then rotates in the second direction opposite to the first direction.

Description

Chemical and mechanical polishing apparatus and method {CHEMICAL MECHANICAL POLISHING APPARATUS AND METHOD}

1 is a SEM photograph showing the appearance of the vertical groove on the polishing pad before use,

Figure 2 is a schematic diagram briefly showing the appearance of the grooves after using the polishing pad for a certain time,

3 is a view briefly showing the operation of the chemical and mechanical polishing apparatus during the first time period according to an embodiment of the present invention,

4 is a view briefly showing the operation of the chemical and mechanical polishing apparatus of FIG. 3 during the second time period.

The present invention relates to a chemical and mechanical polishing apparatus capable of suppressing groove pull on a polishing pad and a chemical and mechanical polishing method using the same.

In general, a semiconductor device is manufactured by performing a series of unit processes such as a thin film forming process, an etching process, a photolithography process, an etching process, an ion implantation process, and a polishing process. Among these unit processes, the polishing process has emerged as an important process technology for improving the structural and electrical reliability of semiconductor devices. In recent years, such a polishing process includes chemical reaction between a slurry and a thin film to be polished, polishing pads, and polishing contained in the slurry. Chemical and mechanical polishing (CMP) processes for polishing the thin film to be polished by using mechanical friction between particles and the thin film to be polished are mainly applied.

The CMP apparatus for this purpose is typically a polishing pad fixed on a rotating table, a polishing head for fixing and rotating a semiconductor substrate on which a polishing target thin film is formed on the polishing pad, a slurry supply unit for supplying a slurry on the polishing pad; And a polishing pad conditioner rotating on the polishing pad to adjust a surface state of the polishing pad. In addition, a plurality of grooves are formed on the surface of the polishing pad for the flow of the slurry.

The CMP process of the polishing target thin film on the semiconductor substrate using such a conventional CMP apparatus is as follows.

First, the polishing target thin film on the semiconductor substrate is polished by rotating the semiconductor substrate fixed to the polishing head while supplying the slurry on the polishing pad to the slurry supply unit. That is, in this polishing process, as the semiconductor substrate on which the thin film to be polished is formed rotates in contact with the polishing pad, a slurry flows through a groove on the polishing pad and chemically reacts with the thin film to be polished on the semiconductor substrate. Mechanical polishing occurs between the abrasive particles included in the slurry and the polishing pad and the polishing thin film to polish the polishing thin film.

However, when the polishing process is performed, slurry residues or various polishing residues derived from the thin film to be polished are accumulated in grooves or micropores on the polishing pad, and the polishing process is performed as the use time of the polishing pad elapses. The uniformity or reliability of the may be lowered.

For this reason, in order to adjust the surface state of the said polishing pad, such as removing the slurry residue and other abrasive residue which accumulate | stored in the groove etc., the conditioning process with respect to the said polishing pad is progressing. Specifically, the conditioning process is performed while the polishing pad conditioner is rotated on the polishing pad, and the in-situ conditioning process and the X which are performed while the polishing process is not performed simultaneously with the polishing process are performed. It can be roughly classified into an ex-situ conditioning process.

In the conventional in-situ and ex-situ conditioning processes, the conditioning process is performed while rotating the polishing pad conditioner in the same direction as the rotational direction of the polishing head and the semiconductor substrate in the polishing process. For this reason, as the use time of the polishing pad has elapsed, groove pull occurs in which the groove ends on the polishing pad are oriented to one side. Accordingly, the polishing pad has a shortened life and polishing residues accumulated in the grooves even when the conditioning process is performed. In many cases, the surface condition of the polishing pad was not properly adjusted because water was not properly removed.

For reference, FIG. 1 is an SEM photograph showing that vertical grooves are formed on the polishing pad before use, and FIG. 2 shows that the ends of the grooves 104 on the polishing pad 102 are pulled to one side after using the polishing pad for a predetermined time. It is a schematic diagram showing the appearance of groove pull.

Accordingly, the present invention is to provide a chemical and mechanical polishing apparatus capable of suppressing groove pull on the polishing pad.

Another object of the present invention is to provide a chemical and mechanical polishing method using the chemical and mechanical polishing apparatus.

The present invention is a polishing pad which is fixed on the rotary table, the groove is formed for the flow of the slurry; A polishing head configured to fix and rotate the semiconductor substrate on which the polishing target thin film is formed on the polishing pad; A slurry supply unit supplying a slurry on the polishing pad; And a polishing pad conditioner that rotates on the polishing pad to adjust the surface condition of the polishing pad, wherein the polishing pad conditioner rotates in a first direction for a first time and is opposite to the first direction for a second time. Provided are chemical and mechanical polishing devices that rotate in two directions.

In the chemical and mechanical polishing apparatus, the polishing head may rotate the semiconductor substrate in the first direction.

In this case, the first time may correspond to a time during which the polishing head rotates the semiconductor substrate in the first direction while chemically and mechanically polishing the thin film to be polished on the semiconductor substrate, and further, the second time. May correspond to a time during which chemical and mechanical polishing of the thin film to be polished on the semiconductor substrate is not performed. In this case, the polishing pad conditioner may rotate at a speed of 0.1 to 100 rpm for the second time.

Further, in the chemical and mechanical polishing apparatus, the first direction may be counterclockwise and the second direction may be clockwise.

In the chemical and mechanical polishing apparatus, the polishing pad fixed on the rotary table may rotate in the same direction as the polishing pad conditioner.

The present invention also provides a chemical and mechanical polishing method using the chemical and mechanical polishing apparatus, wherein the semiconductor substrate fixed to the polishing head is rotated while supplying a slurry on the polishing pad to the slurry supply unit, thereby polishing the polishing target on the semiconductor substrate. Chemically and mechanically polishing the thin film; A first conditioning step of adjusting the surface condition of the polishing pad by rotating the polishing pad conditioner in a first direction for a first time; And a second conditioning step of adjusting the surface condition of the polishing pad by rotating the polishing pad conditioner in a second direction opposite to the first direction for a second time period.

In this chemical and mechanical polishing method, in the chemical and mechanical polishing step, the semiconductor substrate may be rotated in the first direction.

At this time, the chemical and mechanical polishing step may proceed simultaneously with the first conditioning step for the first time, and further, the second time is the time during which the chemical, mechanical polishing and first conditioning step are not in progress. It may correspond to. In this case, in the second conditioning step, the polishing pad conditioner may be rotated at a speed of 0.1 to 100 rpm.

Further, in the chemical and mechanical polishing method, the first direction may be counterclockwise, and the second direction may be clockwise.

In the chemical and mechanical polishing method, the polishing pad may rotate in the same direction as the polishing pad conditioner.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. However, this is presented as an example and thereby does not determine the scope of the present invention.

3 is a view briefly showing the operation of the chemical and mechanical polishing apparatus during the first time according to an embodiment of the present invention, Figure 4 is a view of the operation of the chemical, mechanical polishing apparatus of the second time during It is a figure which shows briefly.

First, according to one embodiment of the invention, a chemical, mechanical polishing apparatus (CMP apparatus) is provided.

3 and 4, the CMP apparatus 200 includes a polishing pad 204 secured on a turntable 202. The polishing pad 204 may be a hard pad made of a material such as polyurethane or a soft pad made of a material such as polytax. In addition, grooves (not shown) for the flow of the slurry are formed on the polishing pad 204, and micropores for accommodating the slurry may be formed. The groove may be formed radially on the polishing pad 204, for example.

In addition, the CMP apparatus 200 includes a polishing head 208 that fixes and rotates the semiconductor substrate 206 on which the polishing target thin film is formed on the polishing pad 204. The polishing head 208 rotates the semiconductor substrate 206 in a predetermined direction in contact with the polishing pad 204 during the polishing process. Accordingly, while the slurry flows through the groove on the polishing pad 204, the slurry reacts chemically with the thin film to be polished on the semiconductor substrate 206, and the abrasive particles included in the slurry and the polishing pad 204 and the polishing layer. Mechanical friction occurs between the thin films to be polished.

In addition, the CMP apparatus 200 includes a slurry supply unit 210 for supplying a slurry on the polishing pad 204. As the slurry is supplied to the polishing pad 204 by the slurry supply unit 210 and the slurry flows through the groove, the thin film to be polished on the semiconductor substrate 206 is polished as described above.

The CMP apparatus 200 also includes a polishing pad conditioner 212 that adjusts the surface condition of the polishing pad 204 while rotating in a predetermined direction on the polishing pad 204.

When the polishing process as described above is performed using the polishing head 208, the polishing pad 204, and the slurry supply unit 210, slurry residues, various polishing residues derived from the polishing target thin film, and the like are subjected to the polishing pad. Accumulated in grooves or micropores on the 204 and the like, the uniformity or reliability of the polishing process may decrease as the use time of the polishing pad 204 elapses. Accordingly, the polishing pad conditioner 212 may be placed on the polishing pad 204 in a predetermined direction to adjust the surface state of the polishing pad 204, such as to remove slurry residue or other polishing residue accumulated in the groove. The conditioning process for the polishing pad 204 proceeds with rotation.

Such conditioning processes are roughly divided into, for example, an in-situ conditioning process that is performed simultaneously with the above-described polishing process and an ex-situ conditioning process that is performed while the polishing process is not in progress. Can be.

On the other hand, in the CMP apparatus 200, the polishing pad conditioner 212 rotates in a first direction, for example, counterclockwise, for a first time and in a second direction opposite to the first direction for a second time. , For example, rotate clockwise. In this case, the first time is performed while the polishing head 204 polishes the thin film to be polished on the semiconductor substrate 206 while rotating the semiconductor substrate 206 in the first direction, that is, the above-described polishing process is performed. May correspond to a time during the second operation, and the second time may correspond to a time during which the polishing process is not performed.

That is, in the CMP apparatus 200, the polishing pad conditioner 212 is in a first direction for a first time, for example, during a polishing process of the polishing target thin film on the semiconductor substrate 206. For example, the in-situ conditioning process may proceed while rotating counterclockwise (see FIG. 3), and during the second time, for example, during the time when the polishing process does not proceed, the first direction may be reversed. The X-situ conditioning process may be performed while rotating in a second direction, for example, a clockwise direction (see FIG. 4; in FIG. 4, the polishing head is omitted since the polishing process does not proceed).

Accordingly, the polishing pad conditioner 212 does not always proceed with the conditioning process while always rotating in only one direction, but may be rotated in opposite directions in each of the in-situ and ex-situ conditioning processes, respectively. Proceed. Thus, even if the use time of the polishing pad 204 elapses, there is a great reduction in the risk of groove pull-up caused by groove grooves on the polishing pad 204, thereby increasing the service life of the polishing pad 204 and the conditioning. The process can effectively remove the abrasive residue accumulated in the grooves.

Meanwhile, when the polishing process is performed on the thin film to be polished on the semiconductor substrate 206, the polishing head 208 and the semiconductor substrate 206 may be in a first direction, for example, the polishing pad conditioner 212. It can rotate in the same counterclockwise direction. As such, the polishing head 208 and polishing pad conditioner 212 can perform polishing and in-situ conditioning, respectively, without interfering with each other.

In addition, in the CMP apparatus 200, the polishing pad 204 fixed on the rotating table 202 may rotate in the same direction as the polishing pad conditioner 212. That is, the polishing pad 204 may rotate in a first direction, for example, counterclockwise, for a first time, and rotate in a second direction, for example, clockwise, for a second time. As such, the conditioning process by the polishing pad conditioner 212 may preferably proceed.

In the CMP apparatus 200, the polishing pad conditioner 212 rotates at a speed of 0.1 to 100 rpm during the second time, for example, during the time when the polishing process is not performed. For example, the X-situ conditioning process may proceed. Rotation of the groove on the polishing pad 204 can be appropriately suppressed by rotating the polishing pad conditioner 212 in the second direction opposite to the first direction at a rotational speed of about this time.

Next, according to another embodiment of the invention, a chemical and mechanical polishing method (CMP method) using the above-described CMP apparatus is provided.

In the above-described CMP apparatus 200, the semiconductor substrate 206 fixed to the polishing head 208 is supplied in a predetermined direction, for example, while supplying a slurry onto the polishing pad 204 to the slurry supply unit 210. The polishing target thin film on the semiconductor substrate 206 is polished by rotating counterclockwise. In this polishing process, the slurry flows through the grooves on the polishing pad 204 and chemically reacts with the polishing target thin film on the semiconductor substrate 206 while the abrasive particles and the polishing pad 204 are included in the slurry. Mechanical friction occurs between the thin film to be polished and the polishing target thin film.

At this time, a slurry residue or various polishing residues derived from the polishing target thin film are accumulated in grooves or micropores on the polishing pad 204 and the like, and thus, as the use time of the polishing pad 204 elapses, Uniformity or reliability may be degraded.

Accordingly, the polishing pad conditioner 212 may be placed on the polishing pad 204 in a predetermined direction to adjust the surface state of the polishing pad 204, such as to remove slurry residue or other polishing residue accumulated in the groove. The first conditioning process is performed on the polishing pad 204 while rotating. More specifically, the polishing pad conditioner 212 is the same as the first direction, for example, the polishing head 208 and the semiconductor substrate 206 during the first time, for example, the time during which the polishing process is performed. The first conditioning process is performed by rotating counterclockwise.

In addition, the second conditioner is rotated by rotating the polishing pad conditioner 212 in a second direction opposite to the first direction, for example, in a clockwise direction, for a second time, for example, a time when the polishing process is not performed. Proceed with the process. In this case, the second conditioning process may proceed while the polishing pad conditioner 212 rotates at a speed of 0.1 to 100 rpm.

And, during the first and second conditioning process, the polishing pad 204 fixed to the rotary table 202 is in the same direction as the polishing pad conditioner 212, that is, the first direction and the second during the first time. It may rotate in the second direction during the time.

In the above-described CMP method, the polishing pad conditioner 212 is in a first direction, for example, during a polishing process for a thin film to be polished on the semiconductor substrate 206, for example, during a first time. , The first conditioning process (in-situ conditioning process) can proceed while rotating in a counterclockwise direction (see FIG. 3), and during the second time, for example, during the time when the polishing process is not in progress, the first direction The second conditioning process (ex-situ conditioning process) may proceed while rotating in a second direction, for example clockwise, as opposed to (see FIG. 4).

Thus, the polishing pad conditioner 212 does not always proceed in the first and second conditioning process while rotating in only one direction, but instead rotates in the opposite direction in, for example, these first and second conditioning processes. Each conditioning process proceeds. Therefore, even if the use time of the polishing pad 204 elapses, there is a significant decrease in the risk of groove pull-up caused by groove grooves on the polishing pad 204, thereby increasing the service life of the polishing pad 204 and the conditioning. The process can effectively remove the abrasive residue accumulated in the grooves.

According to the present invention, there can be provided a chemical and mechanical polishing apparatus and a chemical and mechanical polishing method using the same that can suppress the groove pull on the polishing pad.

Thus, the life of the polishing pad can be further increased, and the surface condition of the polishing pad can be preferably adjusted by effectively removing the polishing residue accumulated in the groove through the polishing pad conditioning process.

Therefore, the uniformity and reliability of the polishing process can be further improved.

Claims

A polishing pad fixed on the rotary table, the groove having a groove for flowing the slurry formed therein;

A polishing head configured to fix and rotate the semiconductor substrate on which the polishing target thin film is formed on the polishing pad;

A slurry supply unit supplying a slurry on the polishing pad; And

A polishing pad conditioner that rotates on the polishing pad to adjust a surface condition of the polishing pad,

Wherein the polishing pad conditioner rotates in a first direction for a first time and rotates in a second direction opposite the first direction for a second time.

The chemical and mechanical polishing apparatus of claim 1, wherein the polishing head rotates the semiconductor substrate in a first direction.

3. The chemical and mechanical polishing apparatus of claim 2, wherein the first time corresponds to a time during which the polishing head rotates the semiconductor substrate in the first direction while chemically and mechanically polishing the thin film to be polished on the semiconductor substrate. .

The chemical and mechanical polishing apparatus of claim 3, wherein the second time corresponds to a time during which chemical and mechanical polishing of the thin film to be polished on the semiconductor substrate is not in progress.

3. The chemical and mechanical polishing apparatus of claim 2, wherein the first direction is counterclockwise and the second direction is clockwise.

2. The chemical and mechanical polishing apparatus of claim 1, wherein the polishing pad fixed on the rotary table rotates in the same direction as the polishing pad conditioner.

5. The chemical and mechanical polishing apparatus of claim 4, wherein the polishing pad conditioner is rotated at a speed of 0.1-100 rpm for the second time period.

A chemical and mechanical polishing method using the chemical and mechanical polishing apparatus of claim 1,

Chemically and mechanically polishing the thin film to be polished on the semiconductor substrate by rotating the semiconductor substrate fixed to the polishing head while supplying the slurry on the polishing pad to the slurry supply unit;

A first conditioning step of adjusting the surface condition of the polishing pad by rotating the polishing pad conditioner in a first direction for a first time; And

And a second conditioning step of rotating the polishing pad conditioner in a second direction opposite the first direction for a second time to adjust the surface condition of the polishing pad.

The method of claim 8, wherein in the chemical and mechanical polishing step, the semiconductor substrate is rotated in a first direction.

10. The method of claim 9, wherein the chemical and mechanical polishing step is performed concurrently with the first conditioning step for the first time.

11. The method of claim 10, wherein the second time corresponds to a time during which the chemical and mechanical polishing steps and the first conditioning step are not in progress.

10. The method of claim 9, wherein the first direction is counterclockwise and the second direction is clockwise.

9. The method of claim 8, wherein the polishing pad rotates in the same direction as the polishing pad conditioner.

12. The method of claim 11, wherein said polishing step rotates said polishing pad conditioner at a speed of 0.1-100 rpm.