METHOD AND DEVICE FOR CLEANING A BRUSH SURFACE HAVING A CONTAMINATION

A method for cleaning a brush surface having a contamination is provided. The method includes steps of: providing a mechanical wave; and stripping off the contamination from the brush surface by the mechanical wave.

DETAILED DESCRIPTION

The present disclosure will be described with respect to particular embodiments and with reference to certain drawings, but the disclosure is not limited thereto but is only limited by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice.

The present disclosure will now be described by a detailed description of several embodiments. It is clear that other embodiments can be configured according to the knowledge of persons skilled in the art without departing from the true technical teaching of the present disclosure, the claimed invention being limited only by the terms of the appended claims.

Hereafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings.

Please refer toFIGS. 1A,1B and2.FIG. 1Ashows a device100for cleaning a brush surface202in accordance with an embodiment of the present disclosure;FIG. 1Billustrates a top view diagram of the device100shown inFIG. 1A; andFIG. 2illustrates a brush surface202with a first surface charge210and a contamination204with a second surface charge212in accordance with another embodiment of the present disclosure. During the post-CMP cleaning period, there are many by-products generated and accumulated on the brush surface202, which includes the contamination204. However, the contamination204on the brush surface202may scratch the wafer surface during the post-CMP cleaning period; thus, the device100shown inFIG. 1Ais used to clean the contamination204from the brush surface202. Referring toFIG. 2, the contamination204includes a contaminant particle206having a particle surface208, the brush surface202has a first surface charge210thereon, the particle surface208has a second surface charge212thereon, and the first surface charge210has an electric polarity the same with that of the second surface charge212. In one embodiment, the device100further includes a detector128used for detecting the electric polarity of one of the first and second surface charges210and212. In another embodiment, the electric polarity is negative, as shown inFIG. 2. For cleaning the brush surface202, a cleaning method is designed to repel the contaminant particle206from the brush surface202and further prevent the contaminant particle206from re-adhering to the brush surface202. The device100is configured to implement the cleaning method mentioned above to clean the brush surface202.

Please refer toFIG. 1A, which illustrates the device100for cleaning the brush surface202mentioned above, wherein the device100includes a cleaning module102configured to enhance the second surface charge212on the particle surface208to repel the contaminant particle206from the brush surface202. In one embodiment, the first surface charge210has a first charge quantity, and the second surface charge212has a second charge quantity, wherein the first charge quantity may be larger, equal or smaller than the second charge quantity. The cleaning module102is configured to enhance the second surface charge212to have a third charge quantity, wherein the third charge quantity is larger than the second electric quantity; thus, the repulsive force between the first surface charge210and the second surface charge212may be strengthen, and the contaminant particle206may be further repelled from the brush surface202. That is to say, the repelled (detached) contaminant particle206may not re-adhere to the brush surface202. In one embodiment, the cleaning module102further includes a first cleaning sub-module104and a second cleaning sub-module106to implement the cleaning method mentioned above.

In one embodiment, the device100further includes a bath108, a megasonic device110and a discharge unit112, wherein the bath108includes a pool region114, a bottom region116, an inlet region118and a first wall120. The brush (not shown) to be cleaned is disposed in the pool region114, and has the brush surface202; and the megasonic device110is disposed in the bottom region116. The discharge unit112includes an overflow region122, a second wall124and an outlet region126, wherein the overflow region122surrounds the first wall120and the second wall124surrounds the overflow region122, as shown inFIG. 1B. Referring toFIG. 1A, the cleaning module104includes the bath108and the discharge unit112; each of the first cleaning sub-module104and the second cleaning sub-module106includes the bath108and the discharge unit112; the first cleaning sub-module104performs a functional water process to reduce the oxidation/reduction potential; and the second cleaning sub-module106performs a chemical process to reduce the zeta potential. It should be appreciate that the effects of performing the functional water process and the chemical process are the same, trying to enhance the second surface charge212on the contaminant particle206, as explained later.

Referring toFIG. 1A, when the brush to be cleaned is disposed in the pool region114, a fluid is provided to the pool region114through the inlet region118. In one embodiment, the inlet region118is controlled to provide the fluid to the pool region114according to the position relationship between the brush and the pool region114. The fluid may include at least one of a functional water and an alkaline solution. In one aspect, for performing the functional water process by the first cleaning sub-module104, the fluid is configured to include the functional water, which is added to the pool region114to form a first solution system. For example, the functional water may include a H2 water, which is added to the pool region114to form the first solution system to reduce the oxidation/reduction potential of the first solution system, wherein the first solution system includes the contaminant particle206, the brush surface202and the H2 water. In another aspect, for performing the chemical process by the second cleaning sub-module106, the fluid is configured to include the alkaline solution, which is added to the pool region114to form a second solution system. For example, the alkaline solution may include an NH4 solution, which is added to the pool region114to reduce a zeta potential of the contaminant particle206, wherein the second solution system includes the contaminant particle206, the brush surface202and the NH4 solution. Adding the alkaline solution is used to facilitate a dissociation of a functional group from the contaminant particle206. In one embodiment, the contaminant particle206is one selected from a group consisting of PSi, Si3N4, SiO2, Al2O3, and the combination thereof. In one embodiment, the functional water is added to the pool region114to reduce the oxidation/reduction potential of the contaminant particle206for enhancing the second surface charge212of the contaminant particle206.

Please refer toFIG. 3, which shows the correlation between the PH and the zeta potential. InFIG. 3, the x axis represents the PH, and the y axis represents the zeta potential (mV). According to the correlation between the PH and the zeta potential, when the potential of hydrogen (PH) increases, the dissociation of the functional group of the contaminant particle206may increase with the potential of hydrogen and the zeta potential of the contaminant particle206is declined; thus, the second surface charge212of the contaminant particle206is to be enhanced to have the third charge quantity. Under the condition that the second surface charge212is enhanced to have the third charge quantity, the repulsive force between the brush surface202and the contaminant particle206is strengthen, thereby preventing the contaminant particle206from re-adhering to the brush surface202. In another embodiment, the fluid is acted as a medium for the mega sonic device110to provide a mechanical wave to the brush surface202to repel the contaminant particle206.

Please refer toFIGS. 1A and 4, whereinFIG. 4shows a diagram of the brush surface202having a contaminant particle206. When the brush begins to be washed, the inlet region118provides the fluid to the pool region114therethrough to form a third solution system in the pool region114, the third solution system includes the fluid, the contaminant particle206and the brush surface202. The megasonic device110is disposed in the bottom region116and provides a mechanical wave to the brush surface202. The mechanical wave forms a physical force to lift off or strip off the contaminant particle206from the brush surface202, as shown inFIG. 4, wherein the mechanical wave travels to the brush surface202through the fluid. In one embodiment, the mechanical wave is a megasonic wave; for example, the megasonic wave typically has a frequency ranging from 0.8 to 2.0 MHz. The megasonic wave repels the contaminant particle206from the brush surface202. In order to prevent the contaminant particle206from re-adhering to the brush surface202, at least one of the functional water (such as the H2 water) and the alkaline solution (such as the NH4 solution) is provided to the pool region114through the inlet region118to form the third solution system. When the functional water is provided to the brush surface202, the functional water reduces the oxidation/reduction potential of the third solution system; and when the alkaline solution is provided to the brush surface202, the alkaline solution reduces the zeta potential of the contaminant particle206. For example, the functional water reduces the oxidation/reduction potential of the contaminant particle206. In one embodiment, the first cleaning sub-module104performs a functional water process to reduce the oxidation/reduction potential of the contaminant particle206when the fluid includes the functional water and is provided to the brush surface202; and the second cleaning sub-module106performs a chemical process to reduce the zeta potential when the fluid includes the alkaline solution and is provided to the pool region114. In one embodiment, the brush surface202may be rotated in order to clean each brush surface202of the brush to be cleaned.

In another embodiment, when the pool region114overflows with the fluid, an overflow region of the fluid flows into the overflow region122and is discharged through the overflow region122and the outlet region126. In another embodiment, it can be inferred that a profile of the device100is a circular shape, as shown inFIG. 1B. In still another embodiment, the profile of the device100may be a rectangular shape.

Please refer toFIGS. 5A and 5B, whereinFIG. 5Aillustrates the experiment result about the remained amount of the contaminant particle206for a first group of cleaning processes, andFIG. 5Billustrates the experiment result about the remained amount of the contaminant particle206for a second group of cleaning processes. As shown inFIG. 5A, the x axis represents the type of the cleaning process performed on the brush surface202, wherein the first group of cleaning processes are denoted in the x axis, and includes the post-CMP cleaning process (after CMP), the ultra pure water without mega sonic process (UPW w/o MS), the ultra pure water plus mega sonic process (UPW+MS), the H2 water plus ultra pure water without mega sonic process (H2-UPW w/o MS) and H2 water plus ultra pure water plus mega sonic process (H2-UPW+MS); and the y axis represents the remained amount of the contaminant particle206after performing each of the processes mentioned above. According to the experiment result inFIG. 5A, after the post-CMP cleaning process, there are more than 20,000 contaminant particles remained on the brush surface202, and after cleaning the brush surface202by applying the ultra pure water without the mega sonic process, there are still 5,500 contaminant particles remained on the brush surface202; in contrast therewith, after cleaning the brush surface202by applying ultra pure water with mega sonic process, there are 680 contaminant particles remained on the brush surface. It can be seen that cleaning the brush surface202by applying the mega sonic process may get better cleaning performance; that is to say, cleaning the brush by applying the mega sonic process may repel much more contaminant particle than cleaning the brush merely with ultra pure water. On the other hand, after cleaning the brush surface202by applying the functional water process (such as H2 plus ultra pure water) without mega sonic process, there are 2,600 contaminant particles remained on the brush surface; in contrast therewith, after cleaning the brush surface202by applying the functional water process (such as H2 plus ultra pure water) with mega sonic process, there are merely less than 200 contaminant particles remained on the brush surface; that is to say, cleaning the brush by applying the mega sonic process may repel much more contaminant particle than cleaning the brush merely with H2 plus ultra pure water. According to the experiment data mentioned above, the method of cleaning the brush surface202by combining the mega sonic process with the functional water process provides the best performance.

As shown inFIG. 5B, the x axis represents the chemical process performed by applying the type of the fluid, wherein the second group of cleaning processes are denoted in the x axis, and includes the post-CMP cleaning process, and the chemical processes performed by applying the anode water, the conventional water, the NH4 solution and the NH4 solution plus the H2 water, respectively; the y axis represents the amount of the contaminant particle remained on the brush surface.FIG. 5also shows the respective potential of hydrogen (PH) of a solution system (such as the first solution system, the second solution system or the third solution system) and the respective oxidation/reduction potential (ORP) of the contaminant particle for each of the chemical processes. According to the experiment result inFIG. 5B, after the post-CMP cleaning process (before the brush cleaning process), there are above 20,000 contaminant particles206remained on the brush surface202. After cleaning the brush surface202by applying the anode water, the remained amount of the contaminant particles206is declined to about 1,500, wherein the solution system has a first pH equal to 2.0, and the oxidation/reduction potential of the contaminant particle equals to 1.35V. After cleaning the brush surface202by applying the conventional ultra pure water, the remained amount of the contaminant particles206is declined to about 500, the solution system has a second pH equal to 7.0, and the oxidation/reduction potential of the contaminant particle206equals to 0.49V. After cleaning the brush surface202by applying the NH4 solution, the remained amount of the contaminant particles206is declined to less than 500, the solution system has a third pH equal to 8.5, and the oxidation/reduction potential of the contaminant particle206equals to 0.31V. Further, after cleaning the brush surface202by applying the NH4 solution plus the H2 water, the remained amount of the contaminant particles206is declined to less than 100, the solution system has a fourth pH equal to 8.5, and the oxidation/reduction potential of the contaminant particle206equals to −0.49V. Based on the above mentioned experiment data, the method of cleaning the brush surface202by combining the functional water process with the chemical process provides an excellent performance.

Please refer toFIG. 6, which illustrates a flow chart of a method600for cleaning the brush surface202having a contamination204in accordance with an embodiment of the present disclosure. In step602, the mega sonic device110provides a mechanical wave. In step604, the mechanical wave strips off the contamination204from the brush surface202. In one embodiment, the contamination202includes a contaminant particle206having a particle surface208, the brush surface202has a first surface charge210thereon, the particle surface208has a second surface charge212thereon, and the first surface charge210has an electric polarity the same with that of the second surface charge212. In order to avoid the detached contaminant particle206attached back to the brush surface202, the method600further includes step606to enhance the second surface charge212on the particle surface208, so as to reinforce the repulsive force between the first surface charge210and the second surface charge212. In step608, the brush surface202is caused to have a motion. In one embodiment, the motion is a rotation.

In accordance with embodiments of the present disclosure, a method for cleaning a brush surface having a contamination is provided. The method includes steps of: providing a mechanical wave; and stripping off the contamination from the brush surface by the mechanical wave.

In various implementations, the contamination includes a contaminant particle having a particle surface, the brush surface has a first surface charge thereon, the particle surface has a second surface charge thereon, the first surface charge has an electric polarity the same with that of the second surface charge, and the method further includes steps of: enhancing the second surface charge, so that the contaminant particle is repelled from the brush surface; and causing the brush surface to have a motion, wherein the electric polarity is negative; and the motion includes a rotation. In one aspect, the step of enhancing the second surface charge on the particle surface is performed by a functional water process. In another aspect, the step of enhancing the second surface charge on the particle surface is performed by a chemical process. The mechanical wave is a megasonic wave, and is applied to the brush surface through a fluid, the fluid includes one of a functional water and an alkaline solution; and the brush surface is used to clean a wafer in a chemical-mechanical planarization process.

In accordance with embodiments of the present disclosure, a method for cleaning a brush surface having a first surface charge and a contaminant particle having a particle surface having a second surface is provided, wherein the first surface charge has an electric polarity the same with that of the second surface charge. The method includes the following steps: causing the second surface charge to be enhanced, so that the contaminant particle is repelled from the brush surface. In one aspect, the electric polarity is negative. In another aspect, the step of enhancing the second surface charge is performed by a functional water process. In still another aspect, the functional water process is performed by adding an H2 water to form a solution system for reducing a oxidation/reduction potential of the solution system. In still another aspect, the step of enhancing the second surface charge is performed by a chemical process. In still another aspect, the chemical process is performed by adding an alkaline solution to reduce a zeta potential of the contaminant particle. In still another aspect, the chemical process is used to facilitate a dissociation of a functional group from the contaminant particle.

In accordance with some embodiments of the present disclosure, a device for cleaning a brush surface having a first surface charge and a contaminant particle having a particle surface having a second surface charge is provided, wherein the first surface charge has an electric polarity the same with that of the second surface charge. The device includes a cleaning module configured to enhance the second surface charge on the particle surface, so that the contaminant particle is repelled from the brush surface. In one aspect, the device further includes a bath, a megasonic device and a discharge unit. The bath includes a pool region, a bottom region, an inlet region and a first wall disposed above the inlet region, wherein the inlet region provides a fluid to the pool region therethrough, and the fluid includes at least one of a functional water and an alkaline solution. The megasonic device is disposed in the bottom region, and provides a mechanical wave. The discharge unit includes an overflow region surrounding the first wall, a second wall surrounding the overflow region, and an outlet region, wherein when the pool region overflows, an overflow portion of the fluid is discharged through the overflow region and the outlet region. In another aspect, the mechanical wave is a megasonic wave. In still another aspect, the cleaning module performs a functional water process to reduce a oxidation/reduction potential of the fluid. In still another aspect, the cleaning module performs a chemical process to reduce a zeta potential of the contaminant particle, and the contaminant particle is one selected from a group consisting of PSi, Si3N4, SiO2, Al2O3, and the combination thereof. In still another aspect, the device further includes a detector used for detecting an electric polarity of one of the first and second surface charges.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclose embodiments. Therefore, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.