Post CMP brush and manufacturing method

Abstract

A brush for post chemical / mechanical polishing cleaning of a semiconductor wafer, comprising a microporous core having continuous air pores and an outer layer of a plurality of loop fibers formed on the outer surface of the microporous core, the brush having a first core flow resistance R1, a second through-surface flow resistance R2, and a third flow resistance R3 across the surface, with R3 < R1 < R2, the brush being provided.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority from U.S. Provisional Patent Application No. 63 / 271,130, filed October 23, 2021, and Provisional Patent Application No. 63 / 288,472, filed with the U.S. Patent Office on December 10, 2021, the entire contents of which are incorporated herein by reference for all purposes. [Background technology]

[0002] Various exemplary embodiments of the present invention relate generally to post-CMP (chemical mechanical polishing) wafer cleaning, and more particularly to an improved post-CMP brush for reduced DIW (deionized water) usage.

[0003] Semiconductor manufacturing processes require the use of large amounts of water. Currently, at each advanced node, a completed 200mm equivalent wafer uses approximately 1300 gallons of water. See Intel Corporate Responsibility Report 2020-21. Based on a global semiconductor production capacity of approximately 135 million 200mm equivalent wafers, water usage is approximately 175 billion gallons / year. See https: / / www.eenewseurope.com / news / top-five-chip-makers-dominate-global-wafer-capacity.

[0004] As semiconductor use continues to grow, water use in semiconductor manufacturing will contribute to strain on the total available natural water resources and their availability for other purposes. Overall water use needs to be reduced to use resources efficiently in line with the current global 1.5°C climate target.

[0005] One of the key elements to reducing water usage is to address it at the source by designing more efficient processes. The Chemical Mechanical Polishing (CMP) process is one of the key processes in semiconductor wafer fabrication and is a huge consumer of water. Advanced chips using 10 nm processes may require a total of 20 or more repetitions of dielectric and metal CMP steps to fabricate a device. The wafer is polished by applying a slurry of metal oxide nanoparticles and chemicals that affect removal with a smooth finish while pressed against a polyurethane pad. The wafer is then cleaned in an integrated post-CMP (PCMP) cleaner using PVA brushes with water flowing through the brushes. See "Process Consistency in Post-CMP Cleaning: Challenges and Opportunities" Singh, Rakesh K et al.

[0006] In addition, water and cleaning agents are sprayed onto the wafer to aid in the removal of particles and debris. PVA brushes are highly porous networks of cross-linked polyvinyl acetate (PVA) with pore sizes ranging from 30-100 μm depending on the manufacturer and type of brush used. Porosity can range from 80-90%. Cleaning is accomplished by pressing a rotating brush filled with water against the spinning wafer.

[0007] A typical PCMP cleaner for 300 mm wafers has two brush stations, each with two brushes. The wafer is cleaned by placing it between the two brushes. Each brush has a water flow rate of about 0.5 liters / min, so the PCMP cleaner requires 2 liters / min of water continuously, while the additional spray nozzles are turned on during wafer cleaning. The spray nozzles use up to 2 liters / min of additional water. Thus, the PCMP cleaner uses 2 liters / min continuously and up to 4 liters / min during wafer cleaning. This equates to 1 million liters (280K gal) / year / cleaner in standby mode, or 2 million liters (560K gal) / year in 100% cleaning mode. Therefore, more DIW-efficient processes and cleaners are highly desirable.

[0008] Existing brush designs use microporous PVA (polyvinyl alcohol) brushes. The amount of water flow required to obtain uniform flow through the brush is a function of porosity and pore size. Higher porosity generally requires higher water flow rates. Also, larger pore size generally requires higher water flow rates. Similarly, the compressibility of the brush is proportional to the pore size and porosity. Thus, in current brush designs, porosity, pore size, and compressibility are strongly coupled to affect the cleaning of the wafer surface. Lowering the porosity can contribute to reducing the water flow rate, but it also reduces the compressibility, affecting the cleaning efficiency. In addition, in conventional brush cleaning, the surface contact is also controlled by the pores. The flow of DIW through the brush and the DIW sprayed on the brush-wafer during cleaning need to be optimized for cleaning. In conventional designs, the flow of DIW through the brush needs to be adequate or large enough to eliminate the risk of back-diffusion of debris into the brush. This is an important consideration that leads to high DIW usage.

[0009] Figure 1(a) shows a simplified schematic of a conventional brush, and Figure 1(b) shows its cross section. A PVA brush core

[0101] is assembled to a mandrel

[0103] , and DIW flows through the mandrel

[0103] and through the brush. During cleaning, the brush nodules

[0102] contact the wafer. Additional DIW

[0104] is sprayed onto the brush during cleaning.

[0010] U.S. Patent No. 4,098,728 describes a polyvinyl acetal sponge and a method for making the same. In this method, the pore space within the sponge is formed by air bubbles, rather than by pore-forming additives such as starch / sulfate combinations. The sponge disclosed in this patent does not have any starch residues, making it particularly useful in medical applications where starch residues can cause a foreign body reaction when in contact with human tissue.

[0011] The use of synthetic sponges and cleaning devices made of polyvinyl acetal is well known. For example, U.S. Patent No. 4,566,911 discloses a roller scrubbing device using polyvinyl acetal material for cleaning semiconductor chips, having a surface layer of elastic polyvinyl acetal material with an average pore diameter in the range of 10 to 200 microns. If the average pore opening is less than 10 μm, the elasticity of the porous elastic material may be low, resulting in poor performance of the cleaning roll. If the average pore opening is more than 200 μm, the porous elastic material will not be suitable for a cleaning roll due to poor pore configuration. If the 30% compressive stress is less than 15 g / cm 2 If the compressive stress is less than 150 g / cm, the porous elastic material is too soft and is distorted by the rotation of the cleaning roll. 2 If it is too high, the porous elastic material becomes too hard and the elasticity decreases.

[0012] US Patent No. 6,080,092 describes an industrial sponge roller device that includes a cylinder of polyvinyl acetal material and a number of frustoconical projections extending from the outer surface of the cylinder. Conventional synthetic sponges have a polymer structure with internal "dead-end pockets" that trap residues and trace metals, and have non-uniform pore sizes that cause fluid retention and residue buildup. As the sponge wears, these metals can come out of the sponge in the form of particulate matter. Such particulate matter can damage the surface to be cleaned. In addition, this type of sponge has small fibrils in the pores that are the result of spaces between the pore-forming additives during the cross-linking reaction. The "cross-linking" is the formation of ester bonds between two adjacent hydroxyl chains that accompanies the reaction of the polyvinyl alcohol with the aldehyde. This reaction hardens and strengthens the resulting material.

[0013] Thus, the brushes have material and structural inhomogeneities that are inherent to the manufacturing process. The material and structural inhomogeneities create uneven contact between the brush and the wafer, which leads to uneven contact forces for cleaning. In addition, the total contact density on a flat surface is inherently limited. A typical PVA brush has 4-10 mm diameter bumps on its surface, which actually perform the cleaning. Thus, the contact area is further reduced. It would therefore be highly advantageous to eliminate the aforementioned and other deficiencies inherent in the prior art. Summary of the Invention

[0014] In view of the above, a new wafer cleaning brush design with controlled surface properties and profile is provided.

[0015] According to one embodiment, there is provided a composite brush for cleaning semiconductor wafers. Thus, the brush comprises: a microporous core having an inner surface and an outer surface; and A sleeve fixedly positioned on an outer surface of the core; Equipped with an inner surface of the core configured to be removably connected onto a mandrel of a wafer cleaning device; The sleeve comprises a woven or knitted fabric having a plurality of free-standing fibers and / or fiber loops extending above the exterior surface of the sleeve.

[0016] The sleeve may comprise free-standing fibers and / or fiber loops extending in a direction that forms an angle of at least 45 degrees with the outer surface of the core.

[0017] The free-standing fibers and / or fiber loops may extend normal or nearly normal to the brush surface.

[0018] The microporous core may be made of a composite plastic material or a microporous plastic material with microchannels and / or open pores to allow water to flow from the inner surface of the core through the core and out the outer surface of the core to the sleeve.

[0019] The free-standing fibres and / or fibre loops may be from 1 micron to 200 microns in diameter, preferably from 1 to 100 microns in diameter, more preferably from 1 to 10 microns in diameter, and may extend to a height of from 0.5 mm to 10 mm above the outer surface, preferably from 1.0 mm to 7 mm above the outer surface of the sleeve, more preferably from 2.0 mm to 5.0 mm above the outer surface of the sleeve.

[0020] The fibers may be composed of a single polymer or a combination of polymers, including polyester, nylon, polyurethane, polyvinyl alcohol (PVA), polyvinyl acetate, or modified fibers such as polyparaphenylene terephthalamide, aromatic polyamides, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene, preferably polyester, nylon, and polyvinyl alcohol (PVA).

[0021] The fiber density at the base of the sleeve is 1 thread / mm 2 ~2000 threads / mm 2 , preferably 25 / mm 2 ~1000 threads / mm 2 , more preferably 50 / mm 2 ~500 threads / mm 2 may be also possible.

[0022] The density of free-standing fibers and / or fiber loops is 1 / mm 2 ~2000 fibers and / or fiber loops / mm 2 , preferably 25 / mm 2 ~1000 threads / mm 2 , more preferably 50 / mm 2 ~500 threads / mm 2 It is.

[0023] The sleeve surface may include both single free-standing fibers and fiber loops.

[0024] The sleeve surface may comprise only textile loops.

[0025] The fibers and / or fiber loops may be arranged in a linear, circumferential, spiral, arcuate, hump, or any other geometric pattern, preferably a pattern that includes a hump or helix.

[0026] The free-standing fibers and / or fiber loops may be formed on the surface of the sleeve along with the base of the sleeve in a single weaving or knitting process.

[0027] The core may be comprised of open cell microporous PVA, polyolefins such as polypropylene, polyurethanes, preferably polypropylene and PVA.

[0028] The core may consist of a meltblown polypropylene filter cartridge.

[0029] The core may be comprised of meltblown nonwoven fibers made of polyolefin, nylon, polyester or urethane.

[0030] In one embodiment, a brush for post chemical / mechanical polishing cleaning of a semiconductor wafer comprises: a composite microporous core having open cell pores that allow the passage of water; an outer sleeve disposed on an outer surface of the microporous core, the outer sleeve comprising a fabric base and a fiber loop on the fabric base extending above an upper surface of the sleeve; Equipped with The brush has a first core flow resistance R1 through the microporous core, a second flow resistance R2 through the base of the sleeve, and a third flow resistance R3 across the surface of the loop; R3 <R1<R2であってもよい。

[0031] The textile loops may be terry textile loops formed together with the base of the sleeve in a single process by weaving or knitting.

[0032] The weave density of the sleeve may be higher than the core brush density.

[0033] The core may have a porosity of 60% to 90%, and the sleeve base may have a porosity of 40% to 70%.

[0034] These and other features and advantages of the present invention will become apparent to those skilled in the art after considering the following description of the presently preferred embodiments of the invention when viewed in light of the accompanying drawings. [Brief description of the drawings]

[0035] [Figure 1(A)] FIG. 1(a) is a simplified schematic diagram of a conventional brush for cleaning wafers. [Figure 1(B)] FIG. 1(b) is a simplified schematic diagram of a conventional brush for cleaning wafers.

[0036] [Figure 2(A)] FIG. 2(a) is a simplified schematic diagram of a wafer cleaning brush according to one embodiment of the present invention.

[0037] [Figure 2(B)] FIG. 2(b) shows a cross section of the brush of FIG. 2A.

[0038] [Diagram 3] FIG. 3 shows a simplified magnified view of a close-up of a fiber loop acting on a particle defect on the surface of a wafer.

[0039] [Figure 4] FIG. 4 shows a top view of a conventional PVA brush with multiple nodules on its top surface.

[0040] [Diagram 5] FIG. 5 shows a top view of a sleeve of a brush according to one embodiment of the invention, illustrating the nodular pattern formed on the sleeve surface by fiber loops. Detailed Description of the Invention

[0041] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. However, it should be noted that the present invention may be embodied in other different embodiments, forms, and modifications thereof, and should not be construed as being limited to the embodiments set forth herein. Rather, the described embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the various aspects and features of the present invention to those skilled in the art to which the present invention pertains. Throughout this disclosure, like reference numerals refer to like parts throughout the various drawings and embodiments of the present invention.

[0042] The drawings are not necessarily to scale and, in some instances, proportions may be exaggerated to clearly illustrate features of the embodiments.

[0043] Further, when an element is referred to as being "connected to" or "coupled to" another element, it will be understood that it may be directly connected or coupled to the other element, or there may be one or more intervening elements. In addition, when an element is referred to as being "between" two elements, it will also be understood that it may be the only element between the two elements, or there may be one or more intervening elements.

[0044] Furthermore, it will be understood that as used herein, the terms "comprise," "comprising," "include," and "including" specify the presence of stated elements but do not exclude the presence or addition of one or more other elements.

[0045] It should also be noted that in some instances, features or elements described in connection with one embodiment may be used alone or in combination with other features or elements of another embodiment, unless otherwise specified, as would be apparent to one skilled in the relevant art.

[0046] Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0047] According to a first embodiment, the brush comprises a microporous core having an inner surface and an outer surface. The inner surface may be attached to a mandrel, which itself may be attached to a cleaning device that provides deionized water to the brush through the mandrel. The inner surface may be configured to be easily assembled and fixed to the mandrel. Various well-known designs may be used. The outer surface of the microporous core is attached to a sleeve that includes a base of fabric and free-standing fibers and / or fiber loops. The base and the free-standing fibers and / or fiber loops may preferably be made of the same material.

[0048] The sleeve may be attached and secured to the microporous core by any suitable means including, for example, sonic welding, heat welding, sewing, or other means for mechanically securing the connection. In one embodiment, the sleeve may be connected to the core in a releasable manner, for example using one or more detachable connectors, allowing the sleeve to be easily replaced with a new sleeve after use.

[0049] The sleeve with the free-standing fibers and / or fiber loops is preferably formed by a weaving or knitting process and has a highly controlled height and spatial arrangement. In one embodiment, several fibers may be combined to make the fabric base, the free-standing fibers, and the fibers or threads used to knit or weave the fiber loops of the sleeve. The sleeve may also have a porous base. The porous base may, for example, be made of the same material as the free-standing fibers and / or fiber loops, and preferably use the same weaving or knitting process. Unless otherwise stated, thread and fiber are used interchangeably without changing the meaning of the present invention.

[0050] Traditional weaving processes involve combining fibers or yarns in the XY direction to create a fabric. Several long monofilament fibers or short lengths of fibers may be processed to produce yarn for the weaving or knitting process. The combination of the diameter of the individual fibers and the number of fibers defines the thickness of the yarn. Denier is a general term for classifying yarns and is the weight in grams of a 9000 meter length of yarn. A yarn of a desired denier can be formed using a few fine fibers or a few coarse fibers. Precision weaving with one or more types of yarns is used to create various patterns and textures for the sleeve. Preferably, a weaving technique known as terry may be used, which involves forming free-standing loops over the entire surface of the fabric or in a predetermined pattern. The loops are formed on the outside (upper side or top surface) of the base of the sleeve to contact the wafer. The loops thus formed can be left in a closed configuration or cut to create free-standing fibers. The bending ability of the free-standing loops or fibers allows for more uniform contact and fluid transport at the wafer-brush interface than a standard flat brush surface.

[0051] The loops can be arranged in a pattern of multiple circumferential rings, for example, with many rings arranged in a horizontal line or across the length of the brush over a portion or the entire length. Another example of a pattern is a spiral pattern. A spiral pattern arrangement provides preferential directional motion along the diameter of the wafer. The loops can also be placed across the brush face in a geometric configuration such as a square grouping of circles of a particular size and pitch. The present invention allows for optimized cleaning efficiency and significant reduction in DIW consumption through a composite brush design with a microporous core and sleeve.

[0052] The present invention enables woven or knitted fiber loops or self-standing fiber patterns on the surface of the sleeve, i.e., an almost infinite number of configurations for an optimal layout and thus cleaning efficiency. The interaction between the thread and the wafer fragments is crucial for removing particles and residues from the wafer surface, so the thread diameter is an important factor. As the thread diameter increases, the rigidity of the loop increases, and as the elongation length of the loop increases, its flexibility and deflection increase. The mechanical properties of the fibers forming the thread also affect the rigidity and deflection. According to the present invention, therefore, the brush structure can be adjusted by a combination of fiber material, individual fiber diameter and thread diameter, and loop elongation and loop density.

[0053] According to one embodiment, the brush comprises a composite cylindrical microporous core having continuous bubble pores forming microchannels, and DIW flows from its inner surface to its outer surface through the microchannels. The sleeve is positioned and fixed on the outer surface of the core. The sleeve comprises a base made of fabric and fiber loops formed on the upper surface (or outer surface) of the base. The brush has a first core flow resistance R1, a second surface penetration flow resistance R2 of the base of the sleeve, and a third flow resistance R3 across the surface of the loop, and R3 < R1 < R2. The flow resistances R1, R2, R3 represent the water resistance per unit thickness in the flow direction at a predetermined water supply pressure. This is an indicator of how easily water flows through the three sections of the composite brush, i.e., the core, the base of the sleeve, and the loop and / or self-standing fibers.

[0054] In one embodiment, the microporous core may be made of polypropylene used for water filter applications. Melt-blown polypropylene filter cartridges are available in several pore sizes and are particularly suitable for this application. Continuous bubble, microporous PVA, urethane or wound filament filters may also be used.

[0055] In one embodiment, the yarn loops may be terry fiber loops formed by weaving or knitting. The surface weave density may be higher than the core brush density. The core may have a porosity of 60-90% and the sleeve fabric surface may have a porosity of 40-70%. Higher or lower ratios may be used as long as the porosity of the core is higher than the porosity of the sleeve fabric. In one embodiment, the brush core may have a radius of 20mm-70mm, the sleeve may have a thickness of 1-2mm, and the yarn loops and / or free-standing fibers may have a free-standing height of 2-5mm.

[0056] The yarns may be comprised of polymeric fibers of at least one of polyester, nylon, polyurethane, polyvinyl alcohol (PVA), polyvinyl acetate, or modified fibers such as polyparaphenylene terephthalamide, aromatic polyamide, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene.

[0057] In conventional brushes, the matrix material is constrained by the larger matrix and the short distance connection to the matrix. In contrast, according to the present invention, the individual nature of the loops and fiber extensions allows for more efficient contact with particles and debris on the wafer. This individual nature of the loops also improves cleaning efficiency by allowing efficient fluid distribution to and from all loop-wafer interfaces. The present invention thus provides an improved surface design for brushes that shows improved cleaning efficiency with fiber loops for cleaning the wafer surface. Improved contact dynamics improves cleaning while reducing DIW and cleaning chemical consumption.

[0058] The present invention employs a terry weaving process with special modified fibers to provide a PCMP brush with significantly improved cleaning performance and reduced DIW usage. The terry process allows for highly tunable wafer contact with high resolution, which significantly improves the cleaning capabilities of PCMP brushes for semiconductor wafers. Modified fiber materials and fiber diameters may be used to adjust design parameters such as loop size and surface density and bending response to optimize cleaning performance. In addition, such surfaces allow for more efficient distribution of DIW and chemicals to the wafer surface. It is understood that terry is one way to create surface textures by weaving or knitting. There are other weaving / knitting patterns that can also be used to generate 3D fiber loops or freestanding fiber structures useful for applications. An advantage of the PCMP brush of the present invention is that DIW usage is significantly reduced compared to existing PCMP brushes.

[0059] The present invention allows for the decoupling of porosity / pore size from compressibility, thereby allowing for increased cleaning efficiency while allowing for reduced water usage.

[0060] Figure 2(A) is a simplified schematic diagram of a brush according to one embodiment of the present invention. Figure 2(B) shows a cross-section thereof. Now, referring to Figures 2(A) and 2(B), there is provided by the present invention a brush generally designated by the numeral 200. Brush 200 includes a cylindrical core 201 having an inner surface 201B and an outer surface 201A. Core 201 is assembled at its inner surface 201B to a mandrel 203.

[0061] The brush 200 further comprises a woven (in the form of a textile) sleeve 206 with a sleeve base 205 and fiber loops 202 on the base 205. The sleeve 206 is fixedly attached to the outer surface of the core 201 while an additional DIW spray 204 is applied during cleaning. In operation, DIW provided by the mandrel 203 flows through the open pores / microchannels of the core into the base of the sleeve and out of the sleeve onto the loops and onto the wafer surface being cleaned. The additional DIW spray 204 may also be sprayed during cleaning.

[0062] Figure 3 shows a close-up of the fiber loop 202 acting on the particle defect 302 on the surface 301 of the wafer 300. The brush of the present invention enables a synergistic effect between the water action and the fiber loop action for cleaning any defects and / or impurities from the surface of the wafer, thereby enabling a significant reduction in water usage without compromising the cleaning effectiveness.

[0063] Since the conventional brush is composed of a homogeneous material composition, the flow resistances in the brush core, surface, and tufts are the same R1. The PCMP brush of the present invention has a core flow resistance R1, a flow resistance R2 on the brush surface, and a flow resistance R3 through the surface, which are different. In order to obtain optimal performance, preferably R3 is less than R1 and R1 is less than R2, that is, R3 < R1 < R2. The flow resistance R2 can be adjusted by the weaving / knitting density of the fibers. A dense weave causes a high pressure drop, while a lightweight weave causes a low pressure drop. The pressure drop at the surface is important because it affects the backflow of the cleaning particles. If the pressure drop is high, the possibility of backflow of the cleaning particles can be minimized. In addition, the low surface fluid flow resistance of the cleaning fiber loop R3 also preferentially directs the flow across the brush surface. It is desirable that the surface weaving density is higher than the core brush density to control R2. In one embodiment, the porosity of the brush core is 70 - 90%, while the porosity of the sleeve fabric surface is 50 - 70%.

[0064] Higher or lower porosities may be used as long as the core porosity is higher than that of the sleeve surface. The material and design of the fibers used to construct the fiber loops affect cleaning efficiency. The bending force imparted by the threads can be adjusted by the properties of the fiber material, the diameter of the fibers and threads, and the free extension of the loops on the surface. Suitable materials for the fibers include polymeric fibers including polyester, nylon, polyurethane, polyvinyl alcohol, polyvinyl acetate, and modified fibers such as polyparaphenylene terephthalamide, traded by DuPont under the name Kevlar®, aromatic polyamides (also known as aramids), polytetrafluoroethylene (PTFE), traded by DuPont under the name Teflon®, ultra-high molecular weight polyethylene (UHMWPE), and the like. The fiber material should be selected such that some softening due to water absorption is desirable, but that prolonged exposure to water and cleaning agents will not significantly affect its properties. It is desirable to use relatively small diameter threads. Microfibers may be used, preferably with thread diameters of 200 microns or less, more preferably with diameters of less than 10 microns. The extension of the fiber loops or fibers above the free surface affects their stiffness, with shorter loop or fiber extensions exhibiting higher stiffness than longer extensions. Efficient wafer cleaning requires good, uniform contact between the wafer and the brush surface. The flatness of the brush surface is a function of the uniformity of the microporous core and the outer woven sleeve. As the gap between the wafer and the brush decreases, the number of loops contacting the wafer surface increases until nearly all of the loops are in contact with the wafer surface. The overall surface height of the loops must be controlled to allow uniform contact with minimal loop compression. The gap can then be adjusted to regulate the cleaning pressure. In one embodiment, loops with nominal extensions in the range of 1-5 mm may be applied.

[0065] Working Example

[0066] sleeve

[0067] Example 1: In one embodiment, a sleeve was made from a thread of 30 polyester fibers, each with a diameter of about 5 microns. The base of the sleeve was approximately 50 / mm 2 and a fiber density of 50 / mm 2 The loops had a loop density of 1000 nm. The loop height was 4 mm. A top view of the sleeve with the nodular pattern is shown in FIG. 5. Each nodule consists of a collection of fiber loops. This is in contrast to the nodules in FIG. 4, which shows a simplified schematic of a conventional PVA brush with multiple PVA nodules on its surface. The nodules in FIG. 4 have a diameter of 10 mm and are 5 mm high.

[0068] Example 2: In another embodiment, a sleeve was made from a thread of 30 polyester fibers, each with a diameter of about 5 microns. The base of the sleeve was about 50 / mm 2 The loops were arranged in a 10 mm ring with a pitch of 15 mm. The loop density was 50 / mm at the ablation. 2 , which is 12.5 / mm on average across the entire brush surface. 2 The loop height was maintained at 4 mm.

[0069] Example of composite brush

[0070] Examples 3 and 4

[0071] The sleeves of Example 1 and Example 2 were attached and secured to the outside of a Parker Corporation polypropylene filter model AVS20M20. The filter cartridge is 20 inches long and 2.5 inches in diameter, with the element rated for 20 micron particle removal. The filter cartridge was cut to match the 218 mm length required to fit into a Lam Corporation Ontrak Synergy wafer cleaner. The filter diameter of 2.5 inches cylinder and 5 mm loop height match the final brush diameter specification of 72 mm.

[0072] Example 5 and Example 6

[0073] The sleeves of Examples 1 and 2 were attached and secured to the exterior of a 20 inch long, 2.5 inch diameter, 25 micron particle filter cartridge model SP-P25-20 manufactured by SpiroPure Corporation.

[0074] Examples 7 and 8

[0075] The sleeves of Examples 1 and 2 were attached and secured to the exterior of a filter cartridge, Model SP-P50-20, manufactured by SpiroPure Corporation, which has the same dimensions as the SP-P25-20 model and is rated for 50 micron particles.

[0076] The brushes of Examples 3 to 8 exhibited a significant improvement in cleaning efficiency and a reduction in water consumption compared to the conventional PVA brush having nubs as shown in FIG.

[0077] While the invention has been described in terms of specific embodiments, it is to be understood that many other embodiments can be envisioned by those skilled in the art to which the invention pertains without departing from the scope or spirit of the invention as defined by the following claims.

Claims

1. 1. A composite cylindrical brush for cleaning semiconductor wafers, said brush comprising: a microporous core having an inner surface and an outer surface; and a sleeve positioned and fixed to the outer surface of the core; Equipped with the inner surface of the core is configured to be connected onto a mandrel of a wafer cleaning device; The brush, wherein the sleeve comprises a woven or knitted fabric having a plurality of free-standing fibers and / or fiber loops extending above the exterior surface of the sleeve.

2. The brush of claim 1 , wherein the sleeve comprises free-standing fibers and / or fiber loops extending in a direction that forms an angle of at least 45 degrees with the outer surface of the core.

3. 2. The brush of claim 1, wherein the free-standing fibers and / or fiber loops extend normal or approximately normal to the brush surface.

4. 2. The brush of claim 1, wherein the microporous core is made of a composite plastic material or a microporous plastic material having microchannels and / or open pores, allowing water to flow from the inner surface of the core through the core and out the outer surface of the core to the sleeve.

5. 2. The brush of claim 1, wherein the freestanding fibers and / or fiber loops are from 1 micron to 200 microns in diameter, preferably from 1 to 100 microns in diameter, more preferably from 1 to 10 microns in diameter, and extend to a height of from 0.5 mm to 10 mm above the outer surface, preferably from 1.0 mm to 7 mm above the outer surface of the sleeve, more preferably from 2.0 mm to 5.0 mm above the outer surface of the sleeve.

6. 10. The brush of claim 1, wherein the fibers are comprised of a single polymer or a combination of polymers including polyester, nylon, polyurethane, polyvinyl alcohol (PVA), polyvinyl acetate, or modified fibers such as polyparaphenylene terephthalamide, aromatic polyamide, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene, preferably polyester, nylon, and polyvinyl alcohol (PVA).

7. The fiber density at the base of the sleeve is 1 thread / mm ２ ~2000 threads / mm ２ , preferably 25 lines / mm ２ ~1000 threads / mm ２ , more preferably 50 pieces / mm ２ ~500 threads / mm ２ 2. The brush of claim 1, wherein:

8. The density of the free-standing fibers and / or fiber loops is 1 fiber / mm ２ ~2000 fibers and / or fiber loops / mm ２ , preferably 25 lines / mm ２ ~1000 threads / mm ２ , more preferably 50 pieces / mm ２ ~500 threads / mm ２ 2. The brush of claim 1, wherein:

9. 10. The brush of claim 1, wherein the sleeve surface includes both single free-standing fibers and fiber loops.

10. 10. The brush of claim 1, wherein the sleeve surface includes only fiber loops.

11. 2. The brush of claim 1, wherein the fibers and / or fiber loops are arranged in a linear, circumferential, spiral, arcuate, nodular, or any other geometric pattern, preferably a pattern comprising nodules or spirals.

12. the free-standing fibers and / or fiber loops are formed on the surface of the sleeve together with the base of the sleeve in a single weaving or knitting process; 2. A brush according to claim 1, wherein the core is made of open-cell microporous PVA, polyolefins such as polypropylene, polyurethane, preferably polypropylene and PVA.

13. 10. The brush of claim 1, wherein the core comprises a polypropylene nonwoven filter cartridge.

14. 10. The brush of claim 1, wherein the core is a fabric made of meltblown polymer.

15. 1. A brush for post chemical / mechanical polishing cleaning of semiconductor wafers, said brush comprising: a composite microporous core having open-cell pores; and an outer sleeve disposed on an outer surface of the microporous core; the outer sleeve comprises a fabric base and a fiber loop on the fabric base extending above an upper surface of the sleeve; the brush has a first core flow resistance R1 through the microporous core, a second flow resistance R2 through the base of the sleeve, and a third flow resistance R3 across the surface of the loop; A brush, where R3<R1<R2.

16. 15. The brush of claim 14, wherein the loops are terry fiber loops formed together with the base of the sleeve in a single process by weaving or knitting.

17. 15. The brush of claim 14, wherein the sleeve weave density is higher than the core brush density.

18. 15. The brush of claim 14, wherein the core has a porosity of 60% to 90% and the sleeve base has a porosity of 40% to 70%.

19. 15. The brush of claim 14, wherein the yarn fibers are polymer fibers made of at least one of polyester, nylon, polyurethane, polyvinyl alcohol (PVA), polyvinyl acetate, or modified fibers such as polyparaphenylene terephthalamide, aromatic polyamide, polytetrafluoroethylene (PTFE), and ultra-high molecular weight polyethylene.

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