KR20060095018A - Method for cleaning shield in the metal deposition chamber - Google Patents

Abstract

The present invention discloses a shield cleaning method of a metal deposition chamber capable of increasing or maximizing productivity. Its cleaning method comprises the steps of: beading the shield to physically remove foreign substances caused on the shield surface; First polishing the beaded shield; First cleaning the shield on which the first polishing is completed; First drying by repeatedly exposing to the nitrogen gas while baking the first cleaned shield; Plasma treating the shield to electrically separate the metal foreign matter from the surface of the first dried shield; Second grinding the plasma treated shield; Second cleaning the second polished shield; And second drying by repeatedly exposing the second cleaned shield to the nitrogen gas while baking the shield, thereby improving productivity compared to the conventional simple physical cleaning method.

Shield, chamber, chopper, polishing, plasma

Description

Method for cleaning shield in the metal deposition chamber

1 is a schematic cross-sectional view showing a general metal deposition equipment.

2 is a flow chart illustrating a shield cleaning method of a metal deposition chamber according to an exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining a semiconductor manufacturing facility, and more particularly, to a shield cleaning method of a metal deposition chamber for cleaning a shield provided to protect an inner wall of a metal deposition chamber for depositing a metal thin film.

Recently, with the rapid development of the information and communication field and the popularization of information media such as computers, semiconductor devices are also rapidly developing. In terms of its functionality, the semiconductor device is required to operate at a high speed and to have a large storage capacity. Accordingly, the manufacturing technology of the semiconductor device is being researched and developed to maximize not only productivity but also production yield.

For example, metal film deposition equipment such as plasma souttering equipment is also rapidly developing.

Hereinafter, a general metal deposition apparatus will be described with reference to the accompanying drawings.

1 is a schematic cross-sectional view showing a general metal deposition equipment.

As shown in FIG. 1, the metal deposition apparatus according to the related art is largely connected to the chamber 1, the target holder 2 installed on the chamber 1, and the target holder 2. It consists of a combination of the wafer heater 5 and the like installed in the lower portion of the chamber (1).

Here, the target holder 2 serves to hold a series of metal targets 4, and a plasma electrode for exciting an inert gas between the metal target 4 and the wafer 6 with ions in a plasma state. Equipped.

In addition, the wafer heater 5 serves to support the process target wafer 6 introduced into the metal film deposition process.

At this time, between the target holder (2) and the metal target (4) is a magnetic plate (3) equipped with a permanent magnet, an electromagnet, etc. to concentrate the inert gas ions excited by the plasma electrode to the metal target (4) Is placed further.

In addition, the magnetic plate 3 serves to induce an increase in the density of the plasma generated inside the chamber 1, so that the final finished metal film can have a certain level or more of quality.

Here, the inside of the chamber 1 is further mounted with a shield 7, for example, stainless steel (hereinafter referred to as SUS), spaced apart from the wall surface of the chamber 1 by a distance. (7) interrupts between the inner wall of the chamber 1 and the process progress space, such that, for example, target metal deposits I deposited toward the process wafer 6 are unnecessarily deposited on the inner wall of the process chamber 1. And thereby prevents unexpected damage of the process chamber 1 in advance.

Since the shield 7 serves to block the target metal deposits I from being deposited on the inner wall of the process chamber 1, when a certain period of time passes, a thick metal foreign material having a predetermined thickness is accumulated on the surface thereof. There is no choice but to show symptoms.

If this shield 7 is left as it is, without further action, anticipation such as contamination of the wafer 6 by particles of the same or similar material as the metal deposits I from the shield 7 may occur. In the conventional case, the shield 7 is periodically replaced, and the aged shield 7 is cleaned through a series of cleaning processes.

Therefore, in the method of cleaning the shield 7 of the metal deposition chamber according to the prior art, the metal foreign matter applied to the shield 7 has an unexpectedly strong bond with the shield 7 base material, and thus the chemicals of strong acids such as hydrochloric acid, sulfuric acid and nitric acid ( chemical) to remove the metal foreign material.

At this time, when removing the metal foreign matter using a strong acid during the cleaning process of the shield (7), part or all of the shield (SUS) of the material (SUS) material may be excessively damaged by the strong acid shield (7) Since the service life of is reduced, the metal foreign matters of a certain portion are removed, and the metal foreign matter remaining on the surface of the shield 7 is removed by a physical method of a series of cleaning processes such as bead treatment, polishing, and cleaning. You can complete

However, the cleaning method of the shield 7 of the metal deposition chamber according to the prior art has the following problems.

The method of cleaning the shield 7 of the metal deposition chamber according to the prior art is difficult to reproducibly remove the metal foreign matter deposited on the surface of the shield 7 through the cleaning of simple physical methods such as bead treatment, polishing, and cleaning. Since the reliability of the cleaning process is difficult to secure, there is a disadvantage in that productivity is lowered.

An object of the present invention for solving the problems according to the prior art described above, the shield cleaning of the metal deposition chamber that can reproducibly remove metal foreign matter from the shield surface, ensure the reliability of the cleaning process to increase or maximize productivity To provide a way.

According to an aspect of the present invention for achieving the above object, a shield cleaning method of a metal deposition chamber, comprising: beading the shield to physically remove foreign substances caused on the shield surface; First polishing the beaded shield; First cleaning the shield on which the first polishing is completed; First drying by repeatedly exposing to the nitrogen gas while baking the first cleaned shield; Plasma treating the shield to electrically separate the metal foreign matter from the surface of the first dried shield; Second grinding the plasma treated shield; Second cleaning the second polished shield; And second drying by repeatedly exposing to the nitrogen gas while baking the second cleaned shield.

Hereinafter, a shield cleaning method of a metal deposition chamber according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art.

2 is a flowchart illustrating a shield cleaning method of a metal deposition chamber according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the shield cleaning method of the metal deposition chamber according to the present invention includes a metal deposition chamber installed on an inner wall of the metal deposition chamber and causing a large amount of metal deposits (hereinafter, referred to as metal foreign matter). After unloading, the unloaded shield is inspected and the shield is immersed in an etching bath in which a chemical containing excellent etching characteristics of the metal foreign matter is contained, depending on the type of metal foreign matter deposited on the shield. Etching the metal foreign matter (S10).

For example, when the main component of the metal foreign matter caused to the shield is aluminum (Al), the present invention uses a H ₂ O ₂ + H ₂ O + HNO ₃ mixture or H ₂ O + KOH mixture as the etching chemical. At this time, the H ₂ O ₂ + H ₂ O + HNO ₃ mixture to maintain a mixing ratio of about 4: 2: 2, H ₂ O + KOH mixture to maintain a mixing ratio of about 20: 1 of the sus (SUS) material The metal foreign matter may be selectively removed from the shield.

As another example, when the main component of the metallic foreign material caused by the shield is titanium (Ti) or titanium nitride (TiN), a mixture of H ₂ O ₂ + H ₂ O + HNO ₃ having a mixing ratio of about 22%: 55%: 22% Alternatively, the metal foreign matter may be selectively removed from the shield using a chemical of H ₂ O + KOH mixture having a mixing ratio of about 20: 1.

In addition, when the metal foreign matter having a thickness of about several millimeters (mm, for example, about 2 mm to about 3 mm) is to be removed, the shield is immersed in the mixture chemical having a predetermined mixing ratio at regular intervals for about a time. The etching process may be performed over eight hours. At this time, when the main component of the metal foreign material is aluminum (Al), the etching property to be etched in the chemical of a predetermined concentration is excellent, so that the shield is immersed in the mixture chemical about 2 to about 3 times to remove the metal foreign matter. However, when the main component of the metal foreign material is titanium (Ti) or titanium nitride (TiN), the metal foreign material may be removed by immersing the shield in the mixture chemical about 4 to 5 times in the chemical. . In addition, when the etching process of the metal foreign matter is completed, the chemical is discharged from the etching bath (cleaning bath), the deionized water overflow (overflow) to clean the shield.

Next, after the etching process is completed, the shield is mounted on a stage, and the shield is mixed with 'mole' and 'sand' by blowing strongly with a force of, for example, about 60 psi to about 100 psi. The remaining metal foreign matter not removed in the process is further removed (S20). In this case, the bead treatment takes about 10 minutes to about 30 minutes, preferably about 20 minutes. Thereafter, the shield may be washed with a cleaning solution such as pure water, or exposed to a purging gas such as nitrogen gas injected at a predetermined pressure to remove the metal foreign matter that has been removed from the shield surface.

The shield is then mounted in a polishing facility, such as a chemical mechanical polishing (CMP) facility, followed by a series of first polishing steps to further remove stains, particles, etc. attached to the shield. (S30). In this case, H ₂ O + KOH mixture having a mixing ratio of about 20: 1 may be used as the abrasive used in the first polishing process. In addition, the first polishing process repeatedly exposes the shield to nitrogen gas to remove contaminants such as ice particles and particles caused by the polishing facility. For example, the first polishing process takes about 5 minutes to about 10 minutes, preferably 8 minutes.

Thereafter, the shield is loaded into an ultrasonic processing apparatus through the first polishing process, and the shield is immersed in a solution such as pure water, ethane or methane, and ultrasonically cleaned (S40). Here, the first cleaning process may remove metal foreign matter that is polished from the surface of the shield by the first polishing process and continuously bonded to the surface of the shield with a predetermined cohesive force from the shield by the ultrasonic vibration. The first cleaning process is, for example, about 20 minutes to about 30 minutes.

Next, the shield, in which the first cleaning process is completed, is mounted in an oven and baked. In addition, the shield baked in the oven is repeatedly exposed to nitrogen (N ₂ ) gas to be first dried (S50). Here, the first drying process is performed in the oven having a predetermined vacuum state to prevent contamination by air pollutants in the shield cleaned by the first cleaning process and to prevent thermal reaction by the baking. Is performed. For example, the shield is first dried by being heated at about 250 ° C. for about 40 minutes in a low vacuum of about 1.0 × 10 ⁻³ Torr.

In addition, the shield on which the first drying process is completed is mounted in a plasma facility to electrically charge the metal foreign matter on the shield surface (S60).

Here, the plasma apparatus is a plasma inert gas ion (eg, positive charge) while a high-pressure charge (eg, negative charge) is applied to the metal foreign matter protruding from the shield surface. The metal foreign material may be charged to the metal foreign material to remove the metal foreign material from the shield surface. In this case, the metal foreign matter may be peeled off from the surface of the shield by the plasma treatment of the shield. For example, the plasma treatment is performed over about a few minutes, the inert gas may be used argon (Ar).

Therefore, the shield cleaning method of the metal deposition chamber according to the present invention, the surface of the shield, the predetermined etching process, bead treatment process, the first polishing process, the first cleaning process and the first drying process is completed, the plasma treatment of the method It is possible to increase or maximize productivity because the foreign metal reproducibly removes the furnace and ensures the reliability of the cleaning process.

However, some or all of the metal foreign matter may be removed by the plasma treatment, but the surface property may be degraded by roughening the surface by damaging the shield base material of the sus material. Therefore, similarly to the first polishing process, the first cleaning process, and the first drying process, a second polishing process, a second cleaning process, and a second drying process are required to make the surface of the shield that has been plasma-processed uniform. do.

Again, the shield is mounted on the polishing facility, and the shield having poor surface properties is second polished (S70). Here, the second polishing process may not only make the surface of the shield uniform, but also remove the metal foreign matter that could not be removed during the plasma treatment. For example, the abrasive used in the second polishing process may also be a mixture of H ₂ O + KOH having a mixing ratio of about 20: 1, and the second polishing process may be performed by the polishing equipment such as the stains and particles. The shield is run for about 5 minutes to about 10 minutes with repeated exposure to nitrogen gas to remove contaminants.

Next, the shield is completed by the second polishing process in a solution such as pure water in an ultrasonic treatment facility and ultrasonically treated (ultra sonic) for a second cleaning (S80). In this case, the second cleaning process may vibrate the shield in the ultrasonic treatment facility to release the metal foreign matters that could not be removed in the second polishing process from the shield. For example, the second cleaning process proceeds for about 30 minutes.

Next, the shield, in which the second cleaning process is completed, is mounted in an oven and baked (S90). In addition, the shield baked in the oven is repeatedly exposed to nitrogen (N ₂ ) gas to dry second. For example, the shield is heated for about 40 minutes to about 1 hour at about 250 ° C. in a low vacuum state of about 1.0 × 10 ⁻³ Torr and then dried.

Finally, although not shown, the second dried shield is vacuum packed and stored until inserted into the metal deposition chamber. In this case, the surface of the second dried shield is inspected to check whether the shield is deformed, and then the shield, which is confirmed to be normal, may be vacuum packed and placed in a carrier box and transported to a storage warehouse.

As a result, the shield cleaning method of the metal deposition chamber according to the present invention, after physically etching, beading, first polishing, first cleaning, and first drying of the shield caused by the metal foreign matters, is electrically plasma treated, The second polishing, the second cleaning and the second drying are physically removed to regenerate the metal foreign matter reproducibly, and the reliability of the cleaning process can be ensured, thereby increasing or maximizing productivity.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Such modifications or equivalent equivalent structures made by those skilled in the art may be variously changed, substituted, and changed without departing from the spirit or scope of the invention described in the claims. For example, detailed conditions of the etching process, the first polishing process, the first cleaning process, the first drying process, the plasma treatment process, the second polishing process, the second cleaning process, and the second drying process may be It may vary depending on the type and thickness of the metal foreign matter caused to the shield.

As described above, according to the present invention, after the physically chemically etched, beaded, first polished, first cleaned and first dried, the shield caused by the metal foreign matter is electrically plasma treated, and then the second physically The polishing, the second cleaning and the second drying can reproducibly remove the metal foreign matter and ensure the reliability of the cleaning process, thereby increasing or maximizing productivity.

Claims (4)

Beading the shield to physically remove foreign substances caused on the shield surface; First polishing the beaded shield; First cleaning the shield on which the first polishing is completed; First drying by repeatedly exposing to the nitrogen gas while baking the first cleaned shield; Plasma treating the shield to electrically separate the metal foreign matter from the surface of the first dried shield; Second grinding the plasma treated shield; Second cleaning the second polished shield; And And secondly drying the second cleaned shield by exposure to the nitrogen gas while baking the second cleaned shield. The method of claim 1, The first polishing and the second polishing is a shield cleaning method of the metal deposition chamber, characterized in that using an abrasive consisting of H ₂ O + KOH mixture. The method of claim 2, And the H ₂ O + KOH mixture has a mixing ratio of about 20: 1. The method of claim 1, And the first cleaning and the second cleaning are ultrasonic cleaning.

Images