JP4362443B2 - Intrusion control subpad - Google Patents

Description

  The present invention relates to a seamless polishing pad with a seamless polishing layer that penetrates into a porous subpad to a substantially uniform depth.

  Silicon wafers are manufactured as precursors from which microelectronic semiconductor components are manufactured. Wafers are obtained by cutting a cylindrical silicon crystal parallel to its main surface to form a thin disk typically 20-30 cm in diameter. The resulting wafer must be polished to provide a flat planar surface in order to properly form electronic components and form an integrated chip semiconductor device. Typically, a 20 cm diameter wafer yields more than 100 microprocessor chips.

  The designed size of such integrated chips is constantly decreasing, while the number of layers applied on the silicon surface increases, for example, due to various sequences of feature deposition, patterning, and etching. I am doing. Current semiconductors typically incorporate up to 7 or 8 metal layers, and future designs are expected to include more layers. With the reduction in circuit size and the increase in the number of layers applied, increasingly stringent requirements are being placed on the smoothness and planarity of silicon and semiconductor wafers throughout the chip manufacturing process. This is because an uneven surface can compromise the patterning process and the overall integrity of the resulting circuit.

  The standard wafer polishing technique currently in use is usually a disk-shaped rotary polishing pad, which must be placed on a pad mounted on a large rotating disk. Typically, a chemical / mechanical polishing (CMP) slurry is applied to the surface of the pad and polished with a rotating pad and slurry while the wafer is maintained in place with an overhead wafer carrier. This is an adaptation of the optical polishing technique used to polish lenses, mirrors, and other optical components.

  A significantly different method is the so-called Linear Planarization Technology (LPT), in which the polishing pad is mounted on a support belt. One such pad and belt combination is described in EP-A-0696495, which uses a conventional flat polyurethane polishing pad bonded to a lower belt of sheet steel or other high strength material. Have.

  The disadvantage of such conventional polishing pads is that they often contain seams. The polishing pad often peels at the seam. In addition, these seams can damage the surface of the polished part, and can limit the ability of the pad to polish the article to a high degree of flatness. A large pad made from two or more small pads should have one or more seams at the junction of the small pads. See, for example, US Pat. No. 6,179,950 (Zhang et al.). Also, when making a belt by joining the ends of a long pad, the belt always has a seam at the joint. See, for example, WO 01/83167 [Eppert et al.].

  One way to solve the seam problem is to directly produce an abrasive layer of the desired size and shape. This can be accomplished, for example, by casting a seamless continuous abrasive layer having a desired size. See, for example, WO 99/06182 [Dudovicz et al.].

  Wafer polishing using either a rotating disk or a circulating belt method typically includes laminating a hard polishing layer on a rigid support. For example, the platen under the rotating abrasive disc typically includes steel, and the circulating abrasive belt typically includes a stainless steel support belt. For this reason, it is often desirable to incorporate a relatively soft, compressible subpad under the polishing layer in the polishing pad. See, for example, US Pat. No. 5,403,228 [Pasch]. When used, the compressible subpad is sandwiched between an abrasive layer and a steel platen or belt support so that the hard abrasive layer can better conform to the surface of the wafer.

  According to conventional manufacturing methods, where the seam can be a problem, the polishing layer is attached to a compressible subpad using, for example, double-sided tape, and the laminated pad is similarly mounted on a steel platen or stainless steel. Install on the belt. We have found that when a seamless polishing layer is formed directly on a compressible subpad by coating it with a curable fluid, the curable fluid penetrates entirely into the porous subpad. It was. This can cause air to move from the subpad into the curable fluid, thereby creating voids in the cured polishing layer. In addition, the fluid penetrates the entire subpad and penetrates from subpad to different depths at different locations. As a result, the thickness of the cured polishing layer formed in these pads varies, as is the thickness of the non-intrusive portion of the subpad under the cured polishing layer. Variations in the polishing layer voids and the thickness of the hardened polishing layer and the thickness of the underlying subpad material cause corresponding variations in the compressibility of the polishing pad. As discussed previously in connection with the seam problem, if the polishing pad is not uniform in nature, even if the article being polished is a silicon wafer, an optical component, or other article, a uniform level of it is required. The pad's ability to provide smoothness and planarity may be limited.

  Thus, a polishing pad comprising a seamless polishing layer that penetrates into a porous subpad to a substantially uniform depth, and a method for producing a seamless porous subpad-containing polishing pad from a curable fluid There is a need for

BRIEF SUMMARY OF THE INVENTION The present invention provides a method for producing a seamless polishing pad that solves the problem of inhomogeneous penetration of a curable fluid into a porous subpad. The present invention also provides a seamless polishing pad that includes a polishing layer that penetrates into a porous subpad to a substantially uniform depth.

  More specifically, the present invention relates to a seamless polishing pad that includes a relatively soft compressible subpad under a relatively hard polishing layer. The polishing pad includes a seamless polishing layer formed by coating the subpad with a curable fluid, where the subpad before coating includes an open area (ie, the subpad is porous). . In accordance with the present invention, the open area of the subpad is not filled with a curable fluid or is filled to a substantially uniform depth throughout the subpad. Accordingly, the present invention provides a seamless polishing pad including a porous subpad on which a seamless polishing layer is coated, and the penetration depth of the polishing layer into the subpad is substantially uniform. I will provide a. Furthermore, the polishing pad can often be compressed substantially uniformly.

Substantially uniform depth penetration can be achieved by applying a barrier layer to the subpad and then coating the subpad (and the barrier layer ) with a curable fluid. The barrier layer preferably has the following properties: (a) it adheres well to both the subpad and the polishing layer, (b) it substantially prevents the curable fluid from penetrating into the subpad. And (c) it does not substantially change the compressibility of the subpad.

According to the method of the present invention, a seamless polishing pad including a polishing layer penetrating into a porous subpad to a substantially uniform depth includes (a) a porous subpad, and (b) a barrier to the subpad. applying a layer, and can be prepared by forming a seamless polishing layer (c) was coated with a hardenable fluid the barrier layer coating subpad. Compared to a polishing pad formed from the same material according to the same method (i.e. a polishing pad not including a barrier) except that step (b) is omitted, the polishing pad manufactured according to the method of the present invention is porous. A polishing layer having a more uniform penetration depth into the quality subpad is included.

  Compared to a polishing pad formed from the same material according to the same method except that step (b) is omitted, the polishing pad manufactured according to the method of the present invention can often be more uniformly compressed.

Detailed Description FIGS. 1 and 1a are cross-sectional views of a polishing pad including a porous subpad 3 and a polishing layer 4. At this time, the polishing layer 4 penetrates into the subpad to a non-uniform depth. ing. The polishing pad is attached on the substrate 1. In FIG. 1, the penetration depth is random throughout the pad. In FIG. 1a, the penetration depth is greater on the right side of the pad and decreases toward the left side. In both cases, the properties of the polishing pad will vary with the depth of penetration and will make it difficult to accurately and precisely produce a seamless polishing pad having the desired properties overall.

  The present invention solves that problem. Illustrated in the cross-sectional view of FIG. 2 is one embodiment of a seamless polishing pad. In this regard, it should be noted that the term “seamless polishing pad” as used herein refers to both a seamless polishing disc and a seamless polishing belt. Further, the term “polishing disc” refers to any polishing pad disc that is generally used on a rotating platen, regardless of the shape of the pad. In other words, most polishing pads used on rotating platens are actually in the shape of a disc, but the term “polishing disc” as used herein refers to such a form of polishing. It is not limited to the pad for use. It should also be noted that the abrasive belt forms a continuous loop in its longitudinal direction, and the abrasive disc has a clear outer perimeter boundary, but the belt and disc look the same in cross section. It is. Thus, these drawings depicting “polishing pads” are precise illustrations of both aspects of the polishing belt and polishing disc of the present invention.

  As shown in FIG. 2, the members of the seamless polishing pad are the porous subpad 3 and the seamless polishing layer 4, where the polishing layer 4 is formed by applying a curable fluid to the surface of the subpad 3. Form. The polishing layer 4 penetrates into the subpad 3 at a substantially uniform distance. Also shown in FIG. 2 are a substrate 1 and an adhesive 2 which are two optional members of a seamless polishing pad. In the disc embodiment, the substrate 1 is a support material such as a rotating platen, while in the belt embodiment, the substrate 1 is a belt constructed from a rigid material such as stainless steel.

Another embodiment of a seamless polishing pad is depicted in cross section in FIG. Subpad 3, polishing layer 4, and substrate 1 are the same as described in connection with FIG. In addition to the subpad 3 and the polishing layer 4, the polishing pad includes a barrier layer 5 as an additional member, which forms the polishing layer 4, so that the subpad 3 is coated with the curable fluid before the subpad 3 is coated. Apply. In this embodiment, the barrier layer 5 and the polishing layer 4 penetrate into the subpad 3 at a substantially uniform distance.

Then, taking each of these members, the subpad 3 can comprise any suitable compressible material. Prior to coating with the barrier layer 5 and / or the polishing layer 4, the subpad 3 must contain open areas such as pores. Furthermore, it is often preferred that the subpad be compressible substantially uniformly.

  Suitable materials for the subpad 3 are well known in the art and include foamed polymers and fibers. The subpad 3 preferably comprises a nonwoven material, such as a synthetic and natural fiber nonwoven, including polyester, polyamide, polyurethane, polyolefin, fluoropolymer, cotton, wool, and combinations thereof. By way of example, a suitable material for use as subpad 3 is the 817 subpad material sold by Thomas West (Sunnyvale, Calif.).

The typical size of the subpad 3 is shown in FIGS . 2 and 3 as a relative relationship with respect to other members of the polishing pad. Typically, the width of the subpad 3 is equal to or smaller than the width of the substrate 1. As previously mentioned, the polishing belt is a continuous loop in the longitudinal direction, whereas the polishing disc has an outer peripheral boundary consisting of separate parts. Thus, in the polishing disc embodiment, the length / diameter of the subpad 3 is typically less than or equal to the length / diameter of the substrate 1. However, in the aspect of the polishing belt, the length of the subpad 3 (the length measured by the inner periphery thereof) is substantially equal to the length of the substrate 1 (the length measured by the outer periphery thereof). Although it is preferable, the length of the subpad 3 may be shorter than the length of the substrate 1. Before coating with a barrier layer 5 or the polishing layer 4, subpad 3 is typically have a thickness of about 0.0254 mm ~ about 5.08 mm, but is more often from about 0.254 mm ~ about 2.54mm Any suitable thickness can be used. When the adhesive layer is applied to the bottom surface and / or the top surface of the subpad, the thickness of the subpad does not include the thickness of the adhesive layer (s).

The barrier layer 5 is typically a material that increases in viscosity after application to the subpad 3. However, when applied to the subpad 3, any material having the following properties can be used as the barrier layer 5: (a) The barrier layer should adhere strongly to both the subpad 3 and the polishing layer 4. Being (b) the barrier layer should substantially prevent the polishing layer 4 from penetrating through the barrier layer into the subpad 3, and (c) the barrier layer of the subpad 3. The compressibility should not be changed substantially.

Although other bonding methods are possible, the barrier layer 5 is bonded to the subpad 3 and the polishing layer 4 by chemical adhesive force and / or mechanical fixing interaction, and promotes strong bonding between the members of the polishing pad. It is preferable that it is possible. The chemical adhesion of the barrier layer will vary depending on the composition of the subpad 3 and the polishing layer 4. Materials that can adhere strongly to the various components of the subpad 3 and polishing layer 4 are well known to those skilled in the art. For example, if the subpad 3 includes polyester fibers and the polishing layer 4 includes polyurethane, polymer adhesives such as polyurethane, acrylic, methacrylic, urethane, cyanoacrylate, vinyl, epoxy, or styrenic adhesives may be used. It will often give good chemical adhesion between the polymer members. Likewise suitable are hot melts, contact cements, anaerobic adhesives (acrylic), UV curable adhesives, emulsions (white adhesives), sealants (silicones, acrylics, urethanes, butyls, and polysulfides). ), Modified phenolic adhesive, plastisol (modified PVC dispersion), rubber adhesive (solution, latex), polyvinyl acetate (emulsion), special adhesive (pressure sensitive, cohesive natural sealing) , Dispersibility, heat sealability, foams and fabrics, etc.), and labeling adhesives (resin adhesives, latex adhesives, etc.). Polyurethane and acrylic adhesives are preferred.

Another way to maximize chemical adhesion is to use a barrier layer 5 that can be chemically bonded to the polishing layer 4. For example, if both the barrier layer 5 and the curable fluid that yields the polishing layer 4 contain reactive molecules from the outset, the curable fluid may be deposited on the barrier layer 5 before it completely reacts. If coated, a cross-linking reaction between members would be possible.

Sub-pads that have a textured surface morphology rather than smooth can also be used to maximize mechanical fixation interactions. For example, you may use the subpad containing a fiber nonwoven fabric. Alternatively or additionally, the surface of the subpad may be modified to add such a rough surface (eg, by buffing, molding, embossing, cutting, scratching, etc.). In a preferred embodiment, the barrier layer 5 is sufficiently fluid to fill up to the bottom of the roughened portion of the subpad 3 when applied, but is viscous enough to take the roughened form of the subpad 3. Including material with properties. Such a combination of properties can be applied at relatively low viscosities, but can be found in materials such as curable fluids that rapidly increase in viscosity after application. An adhesive whose viscosity increases after application, such as an adhesive applied in a volatile solvent, is preferably used as the barrier layer 5. Examples include polyurethane adhesives such as D2596H adhesive and D2597 crosslinker available from DELA, Inc. (Ward Hill, Mass.), Lord Corporation® An acrylic adhesive such as Chemlok® 213 available from Cary, NC) is included. Alternatively or additionally, the surface of the barrier 5 may be modified to add such a rough surface.

The barrier layer 5 must substantially prevent the polishing layer 4 from passing through the barrier layer 5 and into the subpad 3. This requires that the barrier layer 5 be applied as a continuous layer so that substantially no open areas remain where the polishing layer can contact the subpad 3. Materials that can be applied as a continuous layer are well known to those skilled in the art. For example, a polymer such as a polymer adhesive is generally suitable for forming the barrier layer 5.

The barrier layer 5 should not substantially change the compressibility of the subpad 3. That is, the barrier layer 5 is preferably applied to the subpad 3 in such a way that the barrier layer 5 penetrates into the subpad 3 to a substantially uniform depth. Such application methods are well known to those skilled in the art and include spray coating, dip coating, doctor blade coating, coating with a knife on a roll, extrusion, injection of a high viscosity material suspended or dissolved in a low viscosity fluid. Molding, coating, and optionally all of them may then be passed through the coated subpad through a nip roller to further penetrate the barrier layer 5 into the subpad 3. If the barrier layer 5 is applied as a curable fluid, it should be applied in such a way that the entire subpad is uniformly coated with substantially the same viscosity material. Although it is not common, it is possible to make the material used for the barrier layer 5 have substantially the same compressibility as the subpad 3. In that case, even if the barrier layer 5 penetrates into the subpad 3 at various depths, the compressibility of the subpad will not be substantially changed.

The barrier layer 5 can be applied in any suitable thickness, but a typical thickness is about 0.001 mm to about 5.08 mm , often about 0.01 mm to about 2.54 mm , and more often about It will be from 0.00254 mm to about 0.254 mm . The barrier layer 5 may penetrate into the subpad 3 to any suitable depth. However, the barrier layer 5 will typically be less compressible than the subpad 3 and the function of the subpad 3 in the polishing pad is to provide a cushion against the article to be polished, so that the barrier layer 5 Generally only penetrates into the subpad 3 to a limited extent. In order to maximize adhesion, it is generally preferred that the barrier layer 5 penetrates into the subpad 3 at least a distance. For example, the barrier layer 5 may penetrate from about 0 to about 0.0508 mm into the subpad 3. If the cushioning effect is acceptable or desirable, the barrier layer 5 may penetrate deeper into the subpad 3 and may even penetrate all the way to the bottom surface of the subpad 3. FIG. 4 is a cross-sectional view of the polishing pad. In this case, the barrier layer 5 penetrates into the subpad 3 to about half. FIG. 4 a shows a cross section of the polishing pad when the barrier layer 5 has completely penetrated into the subpad 3. By selecting the type of barrier layer 5 and the penetration depth, the degree of cushion provided by the polishing pad can be adjusted.

The seamless polishing layer 4 includes a curable fluid coated on the subpad 3. The curable fluid can be coated directly on the subpad 3 (eg, in the embodiment of FIG. 2) or coated on the subpad 3 coated with the barrier layer 5 (eg, in the manner of FIG. 3). . By “curable fluid” is meant a fluid that has a sufficient fluidity that allows it to be evenly coated on the subpad 3 but that provides a durable and durable seamless polishing layer. Generally, the curable fluid comprises one or more types of reactive molecules (eg, prepolymers, monomers, resins, oligomers, etc.) and one or more types of reaction initiators (eg, polymerization initiators, vulcanizing agents, A catalyst, a curing agent, etc.). Alternatively, the reaction may be initiated using light and / or heat. Optionally, the reactive molecule (s) and initiator (s) may be dissolved in a suitable solvent. The curable fluid is one or more types of reactive molecules that often have the desired stiffness, durability, and seamlessness when the reaction is completed as well as the desired fluidity and coatability characteristics at the beginning of the reaction. including. The curable fluid may optionally contain one or more non-reactive molecules. For example, the polymer can be suspended or dissolved in a suitable solvent and coated on the subpad 3. Upon contact with subpad 3 and / or barrier layer 5, the polymer can be deposited to form polishing layer 4.

The polishing layer 4 should also adhere strongly to the subpad 3 (eg, the embodiment of Example 2) and / or the barrier layer 5 (eg, the embodiment of FIG. 3) so that the polishing pad is less likely to peel off during use. is there. As described above in connection with the barrier layer 5, a polishing layer 4, by maximizing the chemical adhesion and / or mechanical fixation interaction between the subpad 3 and / or the barrier layer 5, Peeling can be prevented. The same measures and techniques as discussed above apply to the polishing layer 4 as well.

The polishing pad preferably does not easily peel the polishing layer 4 from the subpad 3 and / or the barrier layer 5 to such an extent that the polishing layer 4 cannot be peeled without destroying the integrity of the respective layers. In other words, the cohesive strength of one or more members of the polishing pad (subpad 3, seamless polishing layer 4, and optionally barrier layer 5) is less than the adhesive force connecting them is lost. It is lost before.

The peel resistance of the abrasive belt can be tested in the following manner. The polishing belt can be run by a belt roller device as shown in FIG. For example, the belt can be run at about 91.44 m 2 / min on a roller having a diameter of about 30.48 cm . In the meantime, pressure may be applied on the polishing belt by placing a urethane roller having a weight of about 56.7 kg on the belt while it is running. When the contact area of the roller is about 30.48 cm × about 6.35 mm , the applied pressure is about 275790 Pascal . Finally, a liquid such as water or CMP slurry may be poured continuously over the entire width of the belt at a rate of about 1 liter / minute. Preferably, the polishing belt will run in such a device for at least about 50 hours without showing any signs of delamination (ie, no visible gap between the belt members). More preferably, the abrasive belt will run for at least about 75 hours without showing signs of delamination. Most preferably, the abrasive belt will run for at least about 100 hours without showing signs of delamination.

  The seamless polishing layer 4 preferably comprises a non-hollow or cellular polyurethane, such as a polyurethane having a Shore D hardness of about 10 to about 90, although other suitable hardnesses may be used. The curable fluid used to form the polishing layer 4 preferably includes a polyurethane prepolymer and a curing agent therefor. Alternatively, the abrasive layer 4 can be any thermoset or thermoplastic polymer, copolymer, having desired properties such as sufficient flexibility, abrasion resistance, water resistance, and chemical resistance. Or it can also contain a mixture. Examples of possible polymers include polyurethanes, polyamides, polyesters, polycarbonates, polyethers, polyacrylates, polymethacrylates, substituted vinyl polymers, polyacrylamides, polyacrylonitriles, polyketones, silicones, saturated and unsaturated polymer hydrocarbons, Examples include, but are not limited to, fluoropolymers and epoxy resins.

A preferred method of coating the subpad 3 (with or without the barrier layer 5) with a curable fluid that forms the seamless polishing layer 4 is casting. As is known to those skilled in the art, casting involves filling a mold with a curable fluid. The mold typically fills from the top of the opening or through the injection point on the bottom and / or side. One feature of the particularly advantageous casting is that it combines the polishing layer 4 with the substrate 1 to form a continuous outer surface of the polishing pad, completely enveloping the subpad 3 against water intrusion, It is possible to be sealed. That is, the subpad 3 is prevented from coming into contact with a corrosive slurry used in chemical or mechanical polishing of silicon or semiconductor wafers. If a portion of the subpad gets wet, its compressibility will change. If the corrosive slurry degrades the subpad, the subpad compressibility may change further. If the slurry deteriorates the adhesive 2 between the layers of the polishing pad, for example, by degrading the adhesive 2, peeling may occur.

It is preferred to use a casting method in which the curable fluid is applied quickly and continuously over the entire area of the subpad 3. In this way, the possibility of intrusion into the subpad 3 is reduced. Alternatively or additionally, combining the reactive molecule (s) and initiator (s) and applying the curable fluid to any given part of the subpad It is also possible to equalize the time between. In addition, the properties of the curable fluid (eg, composition, temperature, etc.) can be modified to ensure that its viscosity does not substantially increase during the time applied to the subpad. Also these casting methods, with or without barrier layer 5 (e.g., as shown in FIGS. 2 and 3), can be used to make the polishing pad. The polishing pad manufactured according to the above casting method is formed of the same material with the penetration depth into the porous subpad, but in the case of the polishing pad formed using different casting methods. It includes a polishing layer that is more uniform than the penetration depth of the polishing layer. Furthermore, the polishing pads manufactured according to the above casting method are formed from the same material, but often have compressibility uniformity compared to polishing pads formed using different casting methods. Will be improved.

  Other suitable methods for coating the subpad 3 with the curable fluid to form the abrasive layer 4 include reaction injection molding, spray coating, foam blowing, foam coating, compression molding, and extrusion. . As discussed above in connection with the casting method of forming the polishing layer 4, any of these methods can be used to wrap and seal the subpad 3 against water intrusion.

  Modifications may be made to provide optimum polishing performance before, during, or after the formation of the seamless polishing layer 4. The polishing layer 4 may include a porous or microcellular structure throughout a part or the whole of the layer. The microcellular structure can be formed by any suitable technique such as blowing, foaming, adding hollow microelements, particle sintering, and the like. The polishing layer 4 may comprise at least one layer of partially fused polymer particles, or two or more different thermoplastic polymers having different melting points. Abrasive particles or fibers may be added to the polishing layer 4. Furthermore, the polishing surface may have fine or large rough surfaces, grooves or discontinuities. It may have hard and soft polymer areas, or may have transparent and opaque material areas, or it may have uneven areas. It distributes and removes wet slurry and generated scraped particles during the polishing process, reduces hydroplaning, and makes contact between the polishing layer and the article being polished closer, A groove (for example, extending in the belt running direction) may be formed. The slurry may be any suitable including, but not limited to, using one or more high pressure water jets, rotating fine brushes, or hard non-metallic (eg, ceramic) stylus. The method can be used to remove the groove.

As shown in FIGS. 2 and 3, optional member seamless polishing pad is a substrate 1 and adhesive 2. Any suitable adhesive can be used, such as a pressure sensitive adhesive. For example, the subpad 3 may be adhered to the substrate 1 using UHA8791 sold by Avery Dennison Corporation (Pasadena, Calif.). As an example, many commercial subpads have a suitable adhesive backing, such as the 817 subpad material from Thomas West, Inc. (Sunnyvale, Calif.).

  In the polishing disc embodiment, the substrate 1 can be the rotating platen itself. In that case, the bottom of the subpad 3 will be bonded via adhesive 2 to the top of the rotating platen used. Alternatively, the substrate 1 can be any flat support material such as a polymer or plastic sheet. In that case, the support material, not the subpad, would be attached to the top of the rotating platen used.

Next, in terms of the belt aspect, the substrate 1 is preferably in contact with a mechanical roller that rotates the belt during operation, so that the substrate 1 preferably comprises a durable material such as stainless steel. The belt substrate is measured as the inner periphery of the annular belt and has a length of 1 m to 4 m (often 1.5 m to 3 m ) and a width of 0.1 m to 1 m (often 0.2 m to 0.6 m ). Typically, the thickness is from 0.01 cm to 0.6 cm . An additional layer of protective material, such as a polyethylene backing material, can be applied to the inner surface of the substrate 1 to protect the substrate 1 and the mechanical part of the polishing apparatus.

  With this seamless polishing pad, any type of material or layer can be polished in any of the various polishing steps of semiconductor manufacturing. Typical materials to be polished include, but are not limited to, silicon, polysilicon, silicon dioxide, low k dielectric materials, tantalum, tantalum nitride, copper, tungsten, and aluminum. A polishing pad can selectively polish one material over another, or polish different materials at the same rate, or work specifically for certain types of slurries and solutions You may design it. The seamless polishing pad according to the present invention can be applied to polish and flatten other industries such as magnetic disk drives, optical planes and mirrors. Seamless polishing pads are particularly suitable for chemically and mechanically polishing silicon and semiconductor wafers.

As previously mentioned, the seamless polishing pad includes a polishing layer 4 that penetrates into the subpad 3 to a substantially uniform depth. The uniformity of penetration of the polishing layer 4 (and / or the barrier layer 5) into the subpad 3 can be measured according to the following protocol that gives the penetration variation rate (PVF). In a broad sense, a typical measurement of the penetration depth using a caliper is made by cutting and opening the polishing pad and viewing the cross section with a microscope (set at least 30 times). The penetration depth is measured from the top of the subpad (ie, the surface to which the curable fluid is applied). During the application of the curable fluid to the subpad, the viscosity may change, resulting in penetration inhomogeneities (i.e., the material applied when the viscosity is low is higher than the material applied when the viscosity is high). Therefore, the representative distribution of the subpad portions initially, intermediate, and last coated with the curable fluid must be measured. For example, if the polishing pad is manufactured by coating the subpad from one end, continuing across the subpad, and ending at the opposite edge, a typical measurement is Should be done at the same distance from one end to the other.

Furthermore, at least about 40 measurements should be taken so that the pad can be systematically evaluated over its entire area. For example, if a polishing pad is coated from one edge to the other and the distance between the edges is 254 mm , take four equally spaced sections perpendicular to their edges and Ten measurements can be taken at 25.4 mm intervals along.

  Using these obtained measurement values, (a) 2.5% of the highest measurement value (where the polishing layer penetrated the largest distance) was discarded, and the lowest measurement value (the penetration distance of the polishing layer was the smallest) The PVF is calculated by discarding 2.5% of (2), (b) subtracting the remaining lowest measurement from the remaining highest measurement, and (c) dividing the result by the average thickness of the subpad. Therefore, if 40 measurements are taken, (a) the highest and lowest measurements are discarded, and (b) the remaining lowest measurement (second lowest in the original data set) Is subtracted from the remaining highest measurement (the second highest in the original data set) and (c) the result is divided by the average thickness of the subpad. PVF can be obtained by multiplying the result by 100%.

  The PVF of the polishing layer 4 is preferably lower than 75%. More preferably, the PVF of the polishing layer 4 is less than about 50%. Even more preferably, the PVF of the polishing layer 4 is less than about 25%. Even more preferably, the PVF of the polishing layer 4 is less than about 10%. Even more preferably, the PVF of the polishing layer 4 is less than about 5%. Most preferably, the PVF of the polishing layer 4 is less than about 1%.

The PVF of the barrier layer 5 is preferably less than or equal to about 65%. More preferably, the PVF of the barrier layer 5 is less than or equal to about 50%. Even more preferably, the PVF of the barrier layer 5 is less than or equal to about 25%. Even more preferably, the PVF of the barrier layer 5 is less than or equal to about 10%. Even more preferably, the PVF of the barrier layer 5 is less than or equal to about 5%. Most preferably, the PVF of the barrier layer 5 is less than or equal to about 1%.

Seamless polishing pads often have a substantially uniform compressibility. One way to measure compressibility uniformity is to measure the peak value with a durometer. Four 50.8 mm x 50.8 mm samples must be cut at regular intervals from the area of the polishing pad initially coated with the curable fluid. Next, four 50.8 mm x 50.8 mm samples must be cut at equal intervals from the area of the polishing pad covered with the curable fluid. Durometer measurements can be performed using Shore A, B, C, or D gauges, such as those manufactured by Rex Gauge Company (Buffalo Grove, Ill.). Each 50.8 mm x 50.8 mm sample is measured 5 times and the peak value is recorded each time to obtain a total of 40 data points. Average and standard deviation are calculated for 40 durometer measurements, then in-belt non-uniformity (WIBNU) is calculated by multiplying the standard deviation by 6, dividing by the average, and multiplying by 100%.

  The durometer WIBNU of the polishing pad is preferably less than or equal to about 10%. More preferably, the durometer WIBNU of the polishing pad is less than or equal to about 9%. Even more preferably, the durometer WIBNU of the polishing pad is less than or equal to about 8%. Even more preferably, the durometer WIBNU of the polishing pad is less than or equal to about 7%. Even more preferably, the durometer WIBNU of the polishing pad is equal to or less than about 6%. Most preferably, the durometer WIBNU of the polishing pad is less than or equal to about 5%.

Another way to measure compressibility uniformity is to measure the stress at -0.05 deformation. Three 50.8 mm x 50.8 mm samples must be cut at equal intervals from the area initially coated with the curable fluid of the polishing pad. Next, three 50.8 mm x 50.8 mm samples must be cut at equal intervals from the area of the polishing pad covered with the curable fluid. Next, compressive stress deformation data must be obtained for each sample using the following experimental conditions. Each sample must be placed on a stationary platen with a diameter of 15.24 cm with the substrate 1 side down. The top surface of the sample must then be indented with a load platen having a diameter of 1.27 cm . Tests can be suitably performed on an MTS2 / G (MTS Systems Corp. Minneapolis, MN) tester equipped with a 10 kN load cell. The experiment must be performed while controlling the movement at a constant displacement speed of 0.254 mm / min. During the experiment, each sample must be compressed to a predetermined displacement and then the load removed. The top load platen force and displacement are recorded as a function of time. The forces and displacements are then converted to engineering stresses and deformations by the following equations:

Where
● F = Applied force (1 bf)
● A ₀ = Cross-sectional area of the top load platen (in ² )
● d = Displacement of top load platen ● L ₀ = Initial thickness of sample (in)

  The stress at -0.05 deformation is recorded for each sample. Averages and standard deviations are calculated for 6 samples and in-belt non-uniformity (WIBNU) is calculated by dividing the standard deviation by the average and multiplying by 100%.

  The polishing pad stress / deformation WIBNU is preferably less than or equal to about 35%. More preferably, the stress / deformation WIBNU of the polishing pad is equal to or less than about 30%. Even more preferably, the stress / deformation WIBNU of the polishing pad is equal to or less than about 25%. Even more preferably, the stress / deformation WIBNU of the polishing pad is less than or equal to about 20%. Even more preferably, the stress / deformation WIBNU of the polishing pad is equal to or less than about 15%. Most preferably, the stress / deformation WIBNU of the polishing pad is less than or equal to about 10%.

  As noted above, it is generally desirable to make a polishing pad that has a substantially uniform compressibility, but this is not always the case. It is sometimes desirable to make a polishing pad with a predictable non-uniform compressibility. For example, it may be desirable to make a polishing pad that is thick in some areas and thin in other areas and has a thin or thick polishing layer in each of those areas. Such a polishing pad will intentionally have non-uniform compressibility. However, it is still preferred that the polishing layer 4 penetrates into the non-uniform subpad 3 to a uniform depth (measured from the top surface of the subpad, not the flat bottom). The present invention makes it possible to better predict and consistently produce such custom forms. A polishing pad that has been intentionally changed in compressibility can provide, for example, a desired mixed polishing performance from the center to the edge of a silicon wafer. In other words, the present invention is not limited to flat, rectangular subpads. The PVF of such a polishing pad can be measured by dividing the penetration depth range by the average thickness of the subpad and would preferably correspond to the range quoted above.

In accordance with the method of the present invention, the seamless polishing pad comprises: (a) a porous subpad; (b) a barrier layer applied to the subpad; and (c) the barrier layer coated subpad coated with a curable fluid. It can be manufactured by forming a seamless polishing layer. The seamless polishing pad comprises: (a) a substrate; (b) a porous subpad attached to the substrate; (c) a barrier layer applied to the subpad; and (d) the barrier layer coated subpad being cured. It can also be produced by coating with a possible fluid and forming a seamless abrasive layer. The seamless polishing pad comprises: (a) a porous subpad; (b) applying a barrier layer to the subpad; (c) attaching the barrier-coated subpad to the substrate; and (d) curing the barrier-coated subpad. It can also be produced by coating with a possible fluid and forming a seamless abrasive layer. The seamless polishing pad comprises: (a) a porous subpad; (b) applying a barrier layer to the subpad; (c) coating the barrier layer- coated subpad with a curable fluid; It can also be manufactured by (d) attaching the polishing layer and the barrier layer- coated subpad to a substrate.

The polishing pad manufactured according to one of the above methods (polishing pad of the present invention) has the same penetration depth into the porous subpad, but according to the method except the step of applying the barrier layer. And a polishing layer that is made more uniform than the penetration depth of the polishing layer of a polishing pad (same polishing pad but without a barrier layer ) formed from the same material. Improvements in penetration depth uniformity include: (a) Subtracting the penetration variation rate (PVF) of the polishing layer of the polishing pad of the present invention from the PVF of the polishing layer of the same polishing pad but without the barrier layer. (B) The result obtained can be measured by dividing by the PVF of the polishing layer of the same polishing pad but without the barrier layer . The PVF improvement of the polishing layer of the polishing pad of the present invention is preferably equal to or greater than about 10%. More preferably, the PVF improvement of the polishing layer of the polishing pad of the present invention is equal to or greater than about 30%. Even more preferably, the PVF improvement of the polishing layer of the polishing pad of the present invention is equal to or greater than about 50%. Even more preferably, the PVF improvement of the polishing layer of the polishing pad of the present invention is equal to or greater than about 70%. Even more preferably, the PVF improvement of the polishing layer of the polishing pad of the present invention is equal to or greater than about 90%. Most preferably, the PVF improvement of the polishing layer of the polishing pad of the present invention is equal to or greater than about 99%.

The polishing pad manufactured according to the method of the present invention (the polishing pad of the present invention) is the same method, but the polishing pad formed from the same material according to the method except step (b) (with the same polishing pad) The uniformity of compressibility will often be improved as compared to a pad with no barrier layer ). Improvements in compressibility uniformity include (a) subtracting the durometer WIBNU of the polishing pad of the present invention from the durometer WIBNU of the same polishing pad but without the barrier layer , and (b) the result of the same polishing It can be measured by dividing by a durometer WIBNU of a pad which is a pad for use but has no barrier layer . Preferably, the polishing pad durometer WIBNU improvement of the present invention is equal to or greater than about 5%. More preferably, the improvement of the polishing pad durometer WIBNU of the present invention is equal to or greater than about 15%. Even more preferably, the improvement of the durometer WIBNU of the polishing pad of the present invention is equal to or greater than about 30%. Even more preferably, the improvement of the durometer WIBNU of the polishing pad of the present invention is equal to or greater than about 45%. Even more preferably, the improvement of the polishing pad durometer WIBNU of the present invention is equal to or greater than about 55%. Most preferably, the improvement of the polishing pad durometer WIBNU of the present invention is equal to or greater than about 65%.

The improvement in compressibility uniformity is: (a) the stress / deformation WIBNU of the polishing pad of the present invention is subtracted from the stress / deformation WIBNU of the same polishing pad but without the barrier layer , and (b) the result Can be measured by dividing by the stress / deformation WIBNU of the same polishing pad but without the barrier layer . Preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 10%. More preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 25%. Even more preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 40%. Even more preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 55%. Even more preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 70%. Most preferably, the improvement in stress / deformation WIBNU of the polishing pad of the present invention is equal to or greater than about 85%.

Example 1
A polishing pad was manufactured by casting a polyurethane polishing layer on a commercially available subpad material laminated to a circulating stainless steel belt.

Circulating stainless steel belt (substrate 1) had a length of about 2.3876M, width 33.02Cm, and a thickness of 0.0508 cm. The circulating stainless steel band in this example was obtained from Belt Technologies, Inc. (Agawam, Mass.).

Subpad 3 of this example was obtained from Thomas West (Sunnyvale, Calif.). The product number of the subpad is 817. This material is a yellow nonwoven material impregnated with a soft elastomer composition. Despite impregnation, the subpad material is still porous and compressible. A rubber-based pressure sensitive adhesive was supplied to one side of the subpad material and laminated. The subpad was obtained as a rectangular piece having a width of about 30.48 cm and a length of 79.375 cm . The combined thickness of the subpad and adhesive was about 0.7112 mm , where the subpad layer was about 0.508 mm thick and the adhesive layer was about 0.1524 mm thick.

Three subpad pieces were secured to the outer surface of the stainless steel belt using an adhesive backing (Adhesive 2). The subpad was positioned so that the subpad was approximately centered between the ends of the stainless steel, leaving about 1.27 cm of exposed steel along both edges. The three pieces were also placed and, if necessary, trimmed to leave a gap of about 0.762 mm to 1.524 mm between the ends of the pieces.

  A laminate of stainless steel and subpad was placed inside the cylindrical mold with the edges down. The mold is composed of two concentric cylinders arranged on a substrate. The top of the mold is open and there is an inlet that goes up through the substrate.

  The mold containing the stainless steel and subpad laminate was preheated to the desired casting temperature in a furnace. Once the mold has reached the desired temperature, a polyurethane resin (ADIPRENE® LF750D available from Crompton Corporation, Middlebury, Conn.) And a diamine curing agent (Albemarle Corporation) A curable fluid, which is a mixture of Ethacure 300 (E300) manufactured by Baton Rouge, Louisiana, was injected into the mold. Casting and curing conditions including the amount of curing agent, processing temperature, and processing time were set in accordance with guidelines published as LF750D and E300 product data paper available from Crompton.

The polishing layer 4 solidifies within a few minutes after filling the mold. After about 10-15 minutes, the part was removed from the mold and placed in an oven to complete the curing process. After the part was fully cured, it was removed from the furnace, allowed to cool to room temperature, and further processed by a series of secondary operations necessary to trim the part to the desired final size. The final polishing belt has a seamless polishing layer with grooves and buffing surface finish. The total thickness is 2.159 mm to 2.3114 mm , which includes an abrasive layer with a thickness of 0.9398 mm to 1.0922 mm .

  The finished belt was cut into pieces, and the various pieces were used for qualitative peel testing, to determine penetration depth and durometer, and to determine compressive stress deformation data.

  The qualitative peel test shows that the bond between the polishing layer and the subpad is very strong, and the polishing layer can be peeled from the subpad layer without destroying the cohesiveness of the subpad itself. There wasn't.

Penetration depth measurements were made by examining the cross section at each of four different locations approximately 90 ° apart along the length of the belt at 11 points across the width of the belt. Therefore, a total of 44 different locations were examined. Each sample piece examined had a length of about 1.27 cm . The penetration depth of the polishing material into the subpad layer was measured using a microscope and caliper set to 30 times. Since there was a large amount of obvious variation between each sample, the maximum and minimum penetration depths were recorded for each of the 44 sample pieces, yielding a total of 88 actual measurements. The maximum and minimum measurements for each sample were averaged to obtain a representative value for the penetration depth for each sample. Forty-four representative values were classified from maximum to minimum, and then the effective range of penetration was determined after removing 2.5% of the maximum and 2.5% of the minimum. In this example, this resulted in the removal of one maximum value and one minimum value and determining the effective range from the remaining 42 values. Once the penetration depth was determined, the penetration variation rate was calculated by dividing the penetration depth coverage by the average thickness of the subpad layer. This rate of variation will be greater for samples with large penetration depth variations and will be smaller for samples with more consistent penetration depths. The belt in this example has a penetration variation rate (PVF) of 66%.

The durometer measurement was performed on a 50.8 mm × 50.8 mm sample cut from the belt. Four samples were cut from the 76.2 mm wide area at the upper edge of the belt and 4 samples were cut from the 76.2 mm wide area at the lower edge of the belt. These samples were located 50.8 mm to 101.6 mm apart along each edge. The upper edge refers to the edge that was at the top of the mold during casting and the lower edge refers to the edge of the belt that was at the bottom of the mold being cast. The durometer measurement was performed using a Shore C gauge manufactured by Rex Gauge. Each sample of 50.8 mm × 50.8 mm was measured five times, and the peak value was recorded each time. Thus, in this example, a total of 40 data points were recorded for that belt. Averages and standard deviations were calculated from 40 Shore C measurements, then the standard deviation was multiplied by 6 and divided by the average to calculate a measure of inhomogeneity within the belt (WIBNU). The belt of this example resulted in WIBNU (6s) = 9.9% for the peak shore C durometer.

Six additional 50.8 mm x 50.8 mm samples were cut from the belt for compression testing. Three of these samples were taken from near the top edge and three from the bottom edge of the belt. Compressive stress deformation data was obtained for each sample using the following experimental conditions. Each sample was tested by placing the sample on a 15.24 cm diameter stationary platen with the steel side down, and then compressing the top surface of the sample by indenting it with a load platen having a diameter of 12.7 mm. did. The test was performed on an MTS2 / G tester equipped with a 10 kN load cell. The experiment was performed by controlling the displacement at a constant displacement rate of 0.254 cm 2 / min. During the experiment, each sample was compressed to a predetermined displacement and then the load was removed. The force and displacement of the top load platen was recorded as a function of time. The forces and displacements were then converted to engineering stresses and deformations by the following equations:

Where
● F = Applied force (lbf)
● A ₀ = Cross-sectional area of the top load platen (in ² )
● d = Displacement of the top surface load platen ● L ₀ = Initial thickness of sample (in)

  The stress at -0.05 deformation was recorded for each sample. Averages and standard deviations were calculated for 6 samples, and then the in-belt non-uniformity (WIBNU) magnitude was calculated by dividing the standard deviation by the average. The belt of this example has a result of WIBNU (1 s) = 37% with respect to stress at a deformation of −0.05.

  The above measurements indicate that the abrasive material penetrated unevenly into the subpad layer, which resulted in varying compressibility and durometer measurements. Furthermore, it is logical to infer that other properties, such as dynamic mechanical properties, will vary from place to place along the belt, given a non-uniform cross-section.

Example 2
The method of Example 1 was repeated using different nonwoven materials as subpad 3. In this example, a non-woven fabric called AQUILINE (trade name) manufactured by TEXON International (Lester, UK) was used with the same rubber-based pressure sensitive adhesive 2 used in Example 1. And laminated on one side. The Aquiline material contains non-woven polyester fibers with much less impregnating material compared to the 817 material from Thomas West. A comparison of these two different subpad materials using a microscope or SEM shows that the Aquiline material has much more open structure and higher porosity than 817. The aquiline subpad was cut into rectangular pieces having a width of about 30.48 cm and a length of 79.375 cm . The combined thickness of the subpad and adhesive was about 0.9652 mm , where the subpad layer was about 0.8128 mm thick and the adhesive layer was about 0.1524 mm thick.

In accordance with the same method described in Example 1, the subpad was laminated to the stainless steel belt substrate 1, a mold was made, the abrasive layer 4 was cast, and the abrasive belt was finished. The total thickness is 21.59 mm to 2.3114 mm , including a polishing layer thickness of 0.6858 mm to 0.9652 mm . The finished belt was cut and subjected to the same number of tests as described in Example 1. Sample number and technical differences are noted below.

  A qualitative peel test showed that the bond between the polishing layer and the subpad was very strong, and the polishing layer could not be peeled from the subpad layer without destroying the cohesiveness of the subpad itself.

Penetration depth measurements were taken at 11 different locations across the width, 7 different locations along the length, and 77 different locations around the belt. Each of the penetration depths observed in the 12.7 mm long sample was more uniform in this example than in Example 1. Therefore, only one representative intrusion measurement was recorded for each sample instead of two. In this example, the effective range is determined by totaling 4 points. The belt of this example has 91% PVF.

  Durometer measurements (8 samples) and compressive stress deformation measurements (6 samples) were obtained in the same manner as described in Example 1. The belt of this example resulted in WIBNU (6 s) = 15% for the peak shore C durometer and WIBNU (1 s) = 83% for the stress at -0.05 deformation.

  The above measurements indicate that the abrasive material penetrated unevenly into the subpad layer, which resulted in varying compressibility and durometer measurements. Furthermore, it is logical to infer that other properties, such as dynamic mechanical properties, will vary from point to point along the belt, given a non-uniform cross-section. The variability is greater in this example than in Example 1.

Example 3
In this example, the method of Example 2 was repeated except that the barrier layer 5 was applied to the aquiline subpad material before casting of the polishing layer 4. The barrier layer is a polyurethane adhesive composition (D2596H adhesive and D2597 crosslinker available from DELA Inc.) using one of the nonwoven materials using a knife-over-roll technique. It was formed by applying the pressure sensitive adhesive on the other side before laminating the pressure sensitive adhesive on the other side of the nonwoven fabric. The barrier layer material was formed as a very thin film on the upper surface of the nonwoven material and shaped the nonwoven fabric and structural features, substantially sealing the upper surface of the subpad layer. A single belt was used for qualitative peel tests, penetration measurements, hardness measurements, and compression tests. Other abrasive belts were made according to the same method and used to check the lamination integrity with the belt roller apparatus depicted in FIG.

A qualitative peel test showed that the bond between the polishing layer and the subpad was very strong, and the polishing layer could not be peeled from the subpad layer without destroying the cohesiveness of the subpad itself. . Further, several belts according to this example were run on a belt / roller apparatus as shown in FIG. 5 to examine the lamination integrity under dynamic wet conditions. The belt ran at about 91.44 m 2 / min on rollers (100, 11) having a diameter of about 30.48 cm . A urethane roller (8) having a weight of about 56.70 kg placed on one of the mounting rollers (10) for forming a nip through which the belt is continuously moved is continuously applied to the upper surface of the polishing belt. Pressure was applied. The contact area between the upper roller and the top surface of the belt was about 30.48 cm x about 6.35 mm , thereby providing an applied pressure of about 275790 Pascal . Water was continuously poured over the entire width of the belt at a rate of about 1 liter / minute. After running for as long as 67 hours, the abrasive belt showed no signs of delamination. That is, no visible gap was generated between the belt layers.

As described in Example 1, the penetration depth of both the polishing layer 4 and the barrier layer 5 into the subpad 3 was measured and the PVF was calculated. The polishing layer 4 did not penetrate through the barrier layer 5. Barrier layer 5 had a consistent penetration depth of about 50.8 μm to about 101.6 μm . In other words, the PVF of the polishing layer was less than about 1%, while that of the barrier was about 6%. The 6 and Figure 6a, has a substantially uniform depth of penetration depicted, show photomicrographs of scanning electron microscopy of a representative cross-section of the polishing belt (SEM).

  Durometer measurements (8 samples, 5 measurements per sample) and compressive stress deformation measurements (6 samples) were obtained in the same manner as described in Example 1. The polishing belt of this example resulted in WIBNU (6s) = 5.0% for the peak shore C durometer and WIBNU (1s) = 11% for the stress at -0.05 deformation.

Polishing pad of the present embodiment having the barrier layer 5, in terms of except that no barrier layer 5 as compared with the polishing pad of Example 2 made of the same material according to the same manner as the polishing pad of this example Uniformity was improved. That is, the PVF of the polishing layer 4 is improved by at least about 99% [(91-1) / 91] [If the PVF of the barrier layer 5 is compared to Example 2, the improvement is at least about 93% [(91 Note that the peak shore C durometer WIBNU is improved by at least about 67% [(15-5) / 15], and the stress WIBNU at -0.05 deformation is At least about 87% [(83-11) / 83] improvement. In addition, it is logical to infer that other properties, such as dynamic mechanical properties, will be more uniform for the polishing belt of this example as compared to the polishing belts of Examples 1 and 2. Is. It should be noted that these increased uniformity is achieved while maintaining the desired adhesion between the polishing layer 4 and the subpad 3.

Example 4
A highly saturated subpad material was produced using the same materials described in Example 3 and by the same method, but with the following changes. In this example, the aquiline subpad 3 was passed through a bath containing the same barrier layer 5 and a large amount of barrier layer material was introduced into the subpad. Next, the barrier layer introduction subpad was processed through a nip roller and cured, and then a rubber adhesive was laminated on one side. The barrier layer 5 penetrates the entire thickness of the subpad, but the subpad was still porous and more compressible than the non-porous material. It is considered that the porosity was obtained by the expansion of the subpad as it came out of the nip roller. Nevertheless, the barrier layer 5 still prevented the polishing layer 4 from penetrating into the subpad 3.

If PVF and WIBNU were measured as in Example 3, the PVF of both polishing layer 4 and barrier layer 5 was less than about 1%, with the peak shore C durometer WIBNU and -0.05 variations. It is expected that the stress would have been less than about 5% and less than about 10%, respectively. In other words, the polishing pad of the present embodiment, the polishing pad of Example 2 was made in terms of except that no barrier layer 5 of the same material and the same method as the polishing pad of the present embodiment having the barrier layer 5 It is estimated that the uniformity should have been improved compared to That is, the PVF of the polishing layer 4 is improved by at least about 99% (based on the PVF of the barrier layer 5 is improved by at least about 99%), the peak shore C durometer WIBNU is improved by at least about 67%, and -0.05 deformation It is estimated that the stress WIBNU at should have improved by at least about 88%.

Example 5
In this example, Example 1 was repeated except that the barrier layer 5 was applied to the subpad 3 and then the polishing layer 4 was cast. That is, a thin layer of an acrylic adhesive, Chemlok® 213, was brushed uniformly on the surface of the subpad for about 30 minutes before casting. The barrier layer 5 penetrated into the subpad 3 to a depth of about 0.0254 mm to about 0.0508 mm . The polishing layer 4 did not penetrate into the subpad through the barrier. The polishing layer could not be separated from the subpad layer without destroying the cohesiveness of the subpad. The PVF of the barrier layer is about 4.5%.

If PVF and WIBNU were measured as in Example 3, the PVF of polishing layer 4 and barrier layer 5 would be less than about 1% and less than about 5%, respectively, and the peak shore C durometer WIBNU and It is expected that the stress at -0.05 deformation would have been less than about 5% and less than about 10%, respectively. In other words, the polishing pad of the present embodiment having the barrier layer 5, than other points except that no barrier layer 5 polishing example 1 made of the same material and the same method as the polishing pad of this example It is presumed that the uniformity should have been improved compared to the medical pad. That is, the PVF of the polishing layer 4 is improved by at least about 99% (at least about 90% improvement based on the PVF of the barrier layer 5), and the peak shore C durometer WIBNU is improved by at least about 50%, -0.05 deformation It is estimated that the stress WIBNU at should have improved by at least about 70%.

Example 6
A rectangular sheet of 817 subpad material similar to the subpad material described in Example 1 was obtained from Thomas West (Sunnyvale, Calif.). However, these subpads had a pressure sensitive adhesive (PSA) applied to the upper surface as the barrier layer 5 in addition to the rubber-based pressure sensitive adhesive applied to the lower surface. Top surface PSA is routinely used to laminate 817 subpads to polyurethane polishing pads, such as the IC1000 polishing pad available from Rodel, Inc. (Newark, Del.). It was a double-sided tape. The subpad 3 was secured to the stainless steel belt substrate 1 and the polishing layer 4 was cast and worked as described in Example 1 to produce a final polishing belt. However, the polishing layer 4, the subpad 3 and the barrier layer 5 are sometimes easily separated from each other during removal from the mold, or sometimes during machining, or sometimes during actual use. It was not suitable for use as the barrier layer 5 together with other members.

Example 7
This example demonstrates the case where five different polyurethane latexes are used as the barrier layer 5. Different latexes, W-240, W-253, W-290, and W-505, all obtained from CK Witco Corp. (Greenwich, Connecticut) and separated 10.16 cm X30.48 cm Brushed by hand on subpad 3 (817 in Example 1) and dried in oven overnight. The barrier layer 5 had substantially the same surface shape as the surface shape of the subpad 3. Next, the same urethane polishing layer 4 as used in Example 1 was poured onto the upper surface of each barrier layer- coated subpad to cure the polishing layer 4. Each polishing pad member had a high resistance to peeling.

Each polishing pad was examined for penetration depth. In each of the polishing pads, the polishing layer 4 penetrated into the barrier layer 5 but did not exceed it. In the polishing pad formed from W-240 latex, the polishing layer 4 penetrated into the subpad 3 to a depth that varied from about 0.0254 mm to about 0.00754 mm . In those formed from W-253, W-290, and W-505 latex, the polishing layer 4 penetrated into the subpad 3 to a depth that varied from about 0.0254 mm to about 0.0508 mm .

Example 8
This example demonstrates the case where the barrier layer 5 applied as a mixture of a reactive molecule and a reaction initiator therefor is used. Both are mixed together with a urethane prepolymer (Adiprene® L100) obtained from Crompton (Middleberry, Conn.) And a block curing agent [CAYTUR® 31], and then 10 It was poured on the aquiline subpad 3 of 16 cm × 30.48 cm . The mixture was embedded into the subpad using heavy steel rotating pins. The same curable fluid used in Example 1 was poured onto the barrier coated subpad and then placed in an oven to initiate and complete the curing process. The resulting sample was cut and examined for intrusion. No intrusion of the polishing layer 4 to pass through the barrier 5, barrier itself had penetrated to a range of 0.381 mm ~ 0.508 mm. The adhesion between the layers was very good.

Example 9
All belts were made by first fully impregnating the 817 subpad with a combination of prepolymer and curing agent formulated to achieve a 30 Shore A durometer. After fixing the subpad to the stainless steel belt, the 30A formulation was mixed and applied by hand to the subpad. The 30A formulation was catalyzed to cure in a short time in an oven. When the material became solid, the abrasive layer was cast according to the method of Example 1. The final belt showed that the 30A barrier layer penetrated 100% into the subpad. This was consistent at all positions in the belt. Range 0 is interpreted as a rate of change of 0.

Example 10
Smaller pads and full belts were made using sprayed polyurethane varnish as the barrier layer. Both the thin and thick sprayed urethane coatings appeared to be effective as barrier layers, stopping the penetration of the polishing layer into the subpad.

FIG. 1 is a cross-sectional view of a polishing pad illustrating the problem of non-uniform penetration of a polishing layer into a subpad. FIG. 1a is another cross-sectional view of a polishing pad illustrating the problem of non-uniform penetration of the polishing layer into the subpad. FIG. 2 is a cross-sectional view of the polishing pad of the present invention. FIG. 3 is a cross-sectional view of another embodiment of the polishing pad of the present invention. FIG. 4 is a cross-sectional view of another embodiment of the polishing pad of the present invention. FIG. 4a is a cross-sectional view of another embodiment of the polishing pad of the present invention. FIG. 5 depicts a belt roller apparatus that can be used to test the peel resistance of an abrasive belt. FIG. 6 is a scanning electron microscope (SEM) micrograph of the cross section of the polishing pad of the present invention. FIG. 6a is a scanning electron microscope (SEM) micrograph of a cross section of the polishing pad of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base body 2 Adhesive 3 Porous subpad 4 Polishing layer 5 Barrier layer

Claims (14)

A porous subpad layer (3) having a seamless polishing layer (4) thereon as a seamless polishing pad, and a barrier disposed between the polishing layer (4) and the subpad layer (3) includes a layer (5), said barrier layer (5) is not penetrated until uniform in a flat depth into the subpad layer (3), non-uniformity of the compression of the pad as measured by the durometer than 10% Small, seamless polishing pad.   The seamless polishing pad according to claim 1, wherein the barrier layer (5) is adhesively bonded to the seamless polishing layer (4) and the subpad layer (3), thereby preventing peeling. . It said barrier layer (5) is not change the compressibility of the subpad layer (3), seamless polishing pad according to claim 1.   The seamless polishing pad of claim 1, wherein the seamless polishing layer (4) is a curable fluid comprising at least one reactive molecule and at least one reaction initiator.   The seamless polishing pad according to claim 1, wherein the seamless polishing layer (4) is cast and cured on the subpad layer (3). A seamless polishing pad comprising a porous subpad layer (3), a seamless polishing layer (4) formed from a curable fluid, and a barrier layer (5) disposed therebetween, said barrier layer (5) is not penetrated until the subpad layer (3) uniform one depth into the inhomogeneities is less than 10%, the pad for seamless polishing compressible measured the pad by durometer. In a method for manufacturing a seamless polishing pad,
Providing a porous subpad layer (3) and a seamless polishing layer (4) disposed thereon;
Introducing a barrier layer (5) between said seamless polishing layer (4) and said subpad layer (3),
It said barrier layer (5) have have a a step of entering to the porous subpad layer (3) uniform one depth into,
A method for producing a seamless polishing pad, wherein the non-uniformity of compressibility of the pad measured by a durometer is less than 10%. The method for manufacturing a seamless polishing pad according to claim 7 , wherein the seamless polishing layer (4) is cast on the barrier layer (5). In a method for manufacturing a seamless polishing pad,
Introducing barriers layer (5) is a porous subpad layer disposed thereon (3) into a mold,
Heating the mold to a predetermined temperature;
Filling the mold with a curable fluid from the top opening or through an inlet and casting the curable fluid onto the barrier layer (5) to form a polishing layer (4). ,
Thereby penetrate the barrier layer (5) is the subpad layer (3) uniform one depth in a smaller nonuniformity of the compressibility of the pad as measured by the durometer 10%, welt without polishing A method for manufacturing a pad. In a method for manufacturing a seamless polishing pad,
A step of laminating the subpad layer (3) on the outer surface of the circulating stainless steel belt to form a laminate;
Placing the laminate into a cylindrical mold having an inlet and heating the mold to a predetermined temperature;
Disposing a barrier layer (5) on the subpad layer (3);
Injecting a curable fluid into the mold and casting the fluid onto the barrier layer (5) to form a polishing layer (4),
Said barrier layer (5) is penetrated until uniform one depth in said subpad layer (3), less non-uniformity of the compression of the pad as measured by the durometer 10%, producing a seamless polishing pad How to do. The method for producing a seamless polishing pad according to claim 10 , wherein the subpad layer (3) is a nonwoven fabric. The method for manufacturing a seamless polishing pad according to claim 10 , wherein the curable fluid is a mixture of a polyurethane resin and a diamine curing agent. In a method for manufacturing a seamless polishing pad,
Providing a porous subpad layer (3);
Applying a barrier layer (5) to the subpad layer (3);
As engineering to or cast coated seamless polishing layer (4) thereon,
And have a step of entering said barrier layer (5) to said porous subpad layer (3) uniform one depth into,
A method for producing a seamless polishing pad, wherein the non-uniformity of compressibility of the pad measured by a durometer is less than 10% and the seamless polishing layer (4) is a curable fluid. Methods for the barrier layer (5) is to produce the porous subpad layer (3) of invading to 10% or less of the depth of the thickness, seamless polishing pad according to claim 13.

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