Package making – Methods – With contents treating
Reexamination Certificate
1999-03-24
2001-01-23
Vo, Peter (Department: 3721)
Package making
Methods
With contents treating
C053S431000, C053S469000, C053S477000, C206S207000, C206S209000
Reexamination Certificate
active
06176067
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the manufacture of objects. More particularly, the present invention provides a method for cleaning and packaging a sponge or porous polymeric product such as an ultra clean “scrubbing” brush or surface treatment device for the manufacture of integrated circuits, for example. Merely by way of example, the present invention is applied to a packaging method for a scrubbing device for the manufacture of integrated circuits. But it will be recognized that the invention has a wider range of applicability; it can also be applied to the manufacture of semiconductor substrates, hard disks, and the like.
In the manufacture of electronic devices such as integrated circuits, the presence of particulate contamination, trace metals, and mobile ions on a wafer is a serious problem. Particulate contamination can cause a wide variety of problems such as electrical “opens” or “shorts” in the integrated circuit. These opens and shorts often lead to reliability and functional problems in the affected integrated circuit. Mobile ion and trace metal contaminants can also lead to reliability and functional problems in the integrated circuit. The combination of these factors is the main source of lower device yields on a wafer, thereby increasing the cost of an average functional device on the wafer.
Chemical-mechanical polishing (“CMP”) is a commonly used technique for planarizing a film on a wafer prior to subsequent processing of the wafer. CMP often requires introduction of a polishing slurry onto a surface of a film on the semiconductor wafer as the wafer is being mechanically polished against a rotating polishing pad. The slurries typically are water based and can contain fine abrasive particles such as silica, alumina, and other abrasive materials. After polishing is complete, the processed wafers must be cleaned to completely remove residual slurry and other residue from the polishing process to ready the surface for other processing steps such as etching, photolithography, and others.
To clean residual slurry material from the polished surface, cleaning brushes have been used. A cleaning brush of this type often comprises a member that is cylindrical in shape, which generally rotates along a center axis of the cylindrical shaped member. The cleaning brushes are also often made of a foam or porous polymeric material such as polyvinyl alcohol (“PVA”). A combination of rotational movement of the brush and force or pressure placed on the brush against the wafer causes residual slurry materials to be removed from the surface of the wafer. Unfortunately, it has been found that the brushes themselves often contain residual materials from the brush manufacturing process. These residual materials include, among others, residual particles and impurities such as ions and particulate contamination. Given that brushes received directly from a manufacturer are often “dirty” it is difficult to maintain the cleanliness of an integrated circuit manufacturing process by using such dirty brushes. Other impurities also may be introduced to the brush during the packaging process.
In some cases, conventional sponge or porous polymeric materials such as PVA attract microorganisms. More particular, microorganisms such as bacteria often introduce themselves on the wet surfaces and pores of the materials and reproduce at significant rates. These microorganisms contaminate the pores and surface area of the material. They also form particulate contamination, which should not be introduced in the manufacture of electronic devices such as integrated circuits. Furthermore, the microorganisms often degrade the quality of the material, which shortens it's life and resiliency. These and other microorganisms can also degrade the porous polymeric product material.
From the above, it is seen that an improved technique for maintaining cleanliness of a surface treatment device is highly desired.
SUMMARY OF THE INVENTION
According to the present invention, a technique for packaging sponge or porous polymeric products is provided. In an exemplary embodiment, the present invention provides a method for cleaning and packaging an ultraclean surface treatment device, which includes a scrubbing brush for the manufacture of substrates for the electronics industry.
In a specific embodiment, the present invention provides a novel method for packaging a sponge or porous polymeric product, which can be made of PVA and other sponge-like materials. The method includes a step of providing a porous polymeric member, which has an outer surface and may also include inner surfaces, e.g., pores. The member also has a plurality of impurities (e.g., ions, particles) distributed through the member. These impurities can be introduced into the member through the manufacturing process, which is commonly “dirty” and does not provide substantially clean polymeric products. In addition, other impurities may be introduced to the brush during the packaging process. In some embodiments, the impurities are a by-product of the manufacturing process. The present method includes a wash cycle for the member for cleaning purposes that removes a substantial portion of the impurities from the products. The wash cycle can be performed by a washing-type machine, as well as other types of apparatus. The wash cycle can include at least one or more treatments to remove selected impurities from the member. The treatments include washes using an acid, a base, a solvent, and other cleaning materials. In this way, selected impurities are removed in a desirable manner.
Once the washing treatment has concluded, the brush can be removed from the treatment medium and placed within the containment package. In a specific embodiment, these packaging steps are carried out in a Class 100 cleanroom, Class 10 cleanroom, Class 1 cleanroom, or cleaner environment. Preferably, the porous polymeric member is packaged in a preservative such as a basic solution (e.g., ammonium hydroxide) to prevent growth of impurities such as bacteria and the like. This containment package can be single, double, or triple contained, depending upon the application. The containment package can then be heat sealed, which prevents the preservative from evaporating and keeps impurities from coming in contact with the porous polymeric member.
In an alternative embodiment, the wash cycle includes a treatment step that introduces a preservative onto the porous polymeric member. In one aspect, the wash cycle sprays, wets, doses or applies a basic solution such as ammonium hydroxide onto the porous polymeric member. The ammonium hydroxide solution has a concentration in the member ranging from a pH of 9.0 and greater, or preferably a pH of 9.5 and greater. Depending upon the application, other types of preservatives also can be used. These preservatives include TMAH and the like. Once the preservative is deposited on the member, the member is packaged. The packaged member is sealed from the environment, which also prevents the preservative from escaping in some embodiments.
Numerous advantages are achieved using the present invention over conventional techniques. For example, in some embodiments the present invention provides an ultraclean or microclean process for cleaning polymeric products. The present process is easy to use with standard chemicals and provides an improved polymeric product, which tends to introduce fewer particles or impurities onto a substrate to be processed. Additionally, the present brush product is cleaner “out of the box.” That is, the present brush product is much cleaner on delivery than the conventional products on the market at the filing date of this present application. Accordingly, the present brush product is easier to use and provides for a more efficient manufacturing process, which is important in the manufacture of integrated circuits, for example. The present invention can also be applied to other porous polymeric products. Furthermore, the improved packaging technique of the present process maintains the cleanline
Huynh Louis K.
Rippey Corporation
Townsend and Townsend / and Crew LLP
Vo Peter
LandOfFree
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