JP4219940B2 - Polishing pad - Google Patents

Description

  The present invention relates to a polishing pad for polishing or flattening the surface of a workpiece such as a semiconductor device.

  Conventional methods of polishing and planarizing workpieces have been performed with products such as polymeric substrates or polishing pads that are exposed to various working conditions that affect the choice of substrate material. For example, the nature of the workpiece being polished, variations in polishing rate and pressure, the temperature rise that occurs during the polishing operation, and the properties of the polishing slurry used in the operation affect the choice of substrate.

  Such conventional products are generally formed from multilayer laminations or stratified substrates having non-uniform physical properties throughout their thickness. An example of a typical multi-layer pad that is widely used to polish semiconductor devices is the Politex Supreme pad, commercially available from Rodel Incorporated, Newark, Delaware. A typical polytex soupream pad consists of a 1 to 2 mm thick rigid but resilient porous bottom layer of polyester felt and several layers including a polyurethane binder. A sponge-like and elastic microporous urethane layer having a thickness of about 0.05 mm to 0.3 mm is laminated on the bottom layer. The top layer is composed of vertical urethane structures with vertical, inclined pores with the pore slope narrowing towards the top of the pad. The top layer is very soft, porous and elastic. In a typical polishing operation, the top layer of such a multilayer pad wears rapidly. As the top layer wears and subsequent layers are exposed, the polishing characteristics of the pad change, resulting in a non-uniform polishing rate, resulting in non-uniform polishing characteristics on the workpiece surface.

  Conventional polymeric polishing pads often have quality variations due to inaccurate control of polymerization and mixing and cutting and molding of the final pad product. Accordingly, polishing characteristics such as surface quality, raw material removal rate and planarization rate imparted to the workpiece being polished vary particularly significantly between pad batches.

  Therefore, an object of the present invention is to provide a product for polishing or flattening a processed product.

  In order to solve the above problems, the present invention takes the following technical means.

  The present invention is a polishing pad for polishing or planarizing a semiconductor device used with a polishing slurry, wherein the polishing pad has a work surface on the polishing pad and a secondary surface adjacent to the work surface in the polishing pad. A molecular matrix; and a soluble polymer microelement in the polymer matrix, wherein the soluble polymer microelement is located on both the work surface and the subsurface, and the work surface has a convex portion of 0.1 to The polymer matrix relates to a polishing pad having an interval of 10 mm, having irregularities forming a pattern, and a polymer matrix that can become a new work surface when worn.

In addition, the present invention relates to the above polishing pad, wherein the convex portion has a length on the work surface that is smaller than 1000 times the average diameter of the polymer microelement, and the convex portion has an average diameter of the polymer microelement. The present invention relates to the above polishing pad having a depth smaller than 2000 times. Furthermore, the present invention relates to the above polishing pad, wherein the pattern is a mini-size pattern having convex portions with a width of 1 to 5 mm, and the pattern is a macro-sized pattern having convex portions with a width of more than 5 mm. The present invention relates to the polishing pad. In addition, the present invention relates to the above polishing pad, wherein the soluble polymeric microelement is sugar.

The present invention is a polishing pad for polishing or planarizing a semiconductor device used with a polishing slurry, comprising a polymer matrix and a water-soluble sugar in the matrix, the The working surface relates to a polishing pad that is located on both surfaces and has a convex portion that forms a pattern with an interval of 0.1 to 10 mm.

The present invention also relates to the above polishing pad, wherein the convex portion has a length on the work surface that is smaller than 1000 times the average diameter of the water-soluble sugar, and the convex portion has an average diameter of the water-soluble sugar. The present invention relates to the above polishing pad having a depth smaller than 2000 times. Furthermore, the present invention relates to the above polishing pad, wherein the pattern is a mini-size pattern having convex portions having a width of 1 mm to 5 mm, and the pattern is a macro-sized pattern having convex portions having a width of more than 5 mm. The present invention relates to the polishing pad.

  In the polishing pad of the present invention, since the work surface of the polishing pad is regenerated and does not change greatly as the work surface comes into contact with the workpiece, the surface of the workpiece can be uniformly flattened.

  Embodiments of the present invention will be described below with reference to the drawings.

  The planarization of the surface of the workpiece using the polishing pad of the present invention is performed so that the polymer matrix is impregnated with polymer microelements having a plurality of void spaces and has a work surface and a subsurface adjacent to the work surface. By bringing the manufactured product into contact with the work environment, at least a part of the shell of the polymer microelement located adjacent to the work surface is opened, and the opened polymer microelement is embedded in the subsurface. The work surface of the product is regenerated with less hardness than the polymer microelements.

  Referring to the accompanying drawings, like reference numerals generally indicate like elements, but FIGS. 1-3, 5-9 and 11 are labeled 10, 110, 210, 310 and 410, Examples of products used in the present invention are shown.

  Product 10 is preferably a generally circular sheet or polishing pad 12 and is best shown in FIGS. One skilled in the art will recognize that the pad 12 can be, for example, approximately square, rectangular, or any suitable shape as desired.

  The product 10 etc. can itself be used as a polishing pad, or because the polishing slurry provides the desired surface finish on semiconductor devices, silicon devices, crystals, glass, ceramics, polymeric plastic materials, metals, stones or other surfaces. It can also be used as a base material for polishing work used in the above. The polishing pad 12 comprising the product 10 or the like is well known to those skilled in the art and can be used with lubricating oils, coolants and various polishing slurries that are readily available commercially. Typical components of such slurries include liquid media such as water and oil, abrasives such as aluminum oxide, silicon carbide, silicon dioxide, cerium oxide and garnet, bases, acids, salts, surfactants, Alternatively, other drugs depending on the nature of the processed product, or combinations thereof are included.

  The product 10 or the like is useful for changing the surface (also not shown) of a workpiece (not shown) by a polishing operation such as lapping, planarization, polishing or molding, for example. The workpiece to be polished should preferably consist of fragile materials such as quartz, silicon, glass, electronic and optical substrates and high density multilayer electronic devices. The workpiece is a semiconductor device (not shown) consisting of multiple layers of polysilicon, thermal oxide, and metal material, each layer being planarized before subsequent layers are deposited thereon.

  As best shown in FIG. 1, the product 10 preferably comprises a polymeric matrix 14 that is impermeable to aqueous fluid slurries typically used in polishing and planarization operations. The polymeric matrix 14 can be formed from urethane, melamine, polyester, polysulfone, polyvinyl acetate, fluorinated hydrocarbons, and the like, mixtures, copolymers and grafts thereof. Those skilled in the art will appreciate that any other polymer with sufficient toughness and stiffness to grind wear during the polishing operation can be used in a manner consistent with the spirit and scope of the present invention. It is. In the presently preferred form, the polymer matrix 14 comprises a urethane polymer. The urethane polymer is preferably from a polyether-based liquidurethane such as a product of the Adiprene species commercially available from Uniroyal Chemical Co., Middlebury, Connecticut. It is formed. Preferred urethane prepolymers contain from about 9 to 9.3% free isocyanate by weight. Other isocyanate-bearing products and prepolymers can be used in a manner consistent with the spirit and scope of the present invention.

  The urethane prepolymer preferably reacts with polyfunctional amines, diamines, triamines or polyfunctional hydroxyl compounds or mixed functional compounds such as hydroxyl / amine present in the urethane / urea crosslinked network to react with urea chemical bonds and cure / bridges. It is intended to enable the formation of a crossed polymer network. As presently preferred, the urethane prepolymer is 4,4'-methylene-bis [commercially available as the product "Cureene (R) 442" from Anderson Development Co., Adrian, Michigan. It reacts with 2-chloroaniline] ("MOCA").

  As best shown in FIG. 1, the polymer matrix 14 is impregnated with a plurality of polymer microelements 16. Preferably, at least some of the polymer microelements are totally flexible. Suitable polymeric microelements include inorganic salts, sugar and water soluble gums and resins. Examples of such polymeric microelements include polyvinyl alcohol, pectin, polyvinyl pyrrolidone, hydroxyethylcellulose, methylcellulose, hydropropylmethylcellulose, carboxymethylcellulose. ), Hydroxypropylcellulose, polyacrylic acids, polyacrylamides, polyethylene glycols, polyhydroxyetheracrylites, starch, maleic acid copolymers ), Polyethylene oxide, polyurethanes, and combinations thereof. The microelements 16 can be chemically modified to alter solubility, swelling power and other properties, for example by branching, blocking, and crosslinking.

  As presently preferred, each of the polymeric microelements 16 has an average diameter of about 150 μm or less, and more preferably has an average diameter of about 10 μm. One skilled in the art will appreciate that the average diameter of the microelements can vary and that the polymeric matrix 14 can be impregnated with the same or different sized microelements 16 or a mixture of different microelements 16 as required.

The presently preferred form is that each of the polymeric microelements 16 is spaced from about 1 μm to about 100 μm. Preferably, the polymeric microelements 16 are evenly distributed by high shear mixing substantially throughout the polymeric matrix 14. The resulting composite mixture is transferred to a conventional mold before the viscosity of the reactive urethane polymer becomes too high to allow sufficient blending with the microelement polymer mixture. One skilled in the art will appreciate that the low viscosity window may vary at different temperatures with various thermoset plastics and curing agents. The resulting mixture gels in the mold for about 15 minutes. Gelation time may vary based on factors such as temperature and polymer matrix and microelement selection. The mixture is then cured at about 93-107 ° C. ( about 200-225 ° F.) for about 4-6 hours and cooled to room temperature ( about 21 ° C. ( about 70 ° F. ) ). The curing temperature can vary among the factors, particularly depending on the polymer matrix and the type of microelement used.

  The resulting product 10 is removed from the mold, cut to the desired thickness by operations such as cutting and slicing, and then shaped to form the polishing pad 12. One skilled in the art will appreciate that the shaped mixture can be processed to any thickness or shape as needed in accordance with the present invention in cutting, slicing and other operations.

  Depending on the intended use or operation, the shape of at least some of the polymer microelements 16 may be generally spherical as shown in FIG. Preferably, such microspheres are hollow and each sphere has a shell having a thickness of about 0.1 μm.

  As best shown in FIG. 1, each polymeric microelement 16 has a void space 22 therein. At least some of the polymeric microelements 16 preferably have a plurality of void spaces 22 therein, as best shown in FIG. Each void space 22 generally contains a gas at a pressure higher than atmospheric pressure to help maintain the structural integrity of each of the microelements 16 ′, 16 on both the working surface 18 and the secondary surface 24 of the polymeric matrix 14. I have to.

  The polymeric microelement can have a permeable or pierceable shell 20 as best shown in FIG. 11, thereby opening a void space 22 in the microelement 16 'to the working environment.

  As best shown in FIG. 1, a preferred example of the product 10 softens when at least some of the polymeric microelements 16 'located on the work surface 18 come into contact with a work environment (not shown) or abrasive slurry. For example, water-soluble cellulose ether such as methyl cellulose dissolves as soon as it comes into contact with the water in the aqueous polishing slurry.

  As best shown in FIG. 1, in another preferred example, at least some of the polymeric microelements 16 'located on the work surface 18 expand immediately upon contact with the work environment. For example, long chain cellulose ether expands as soon as it comes into contact with moisture in the aqueous polishing slurry.

  Product 10 has a work surface 18 and a secondary surface 24 adjacent thereto, as best shown in FIGS. Preferably, the work surface 18 is about 5 μm to about 60 μm thick. The thickness of the product 10 is preferably between about 300 μm and about 400 μm in a direction generally perpendicular to the main plane (not shown) of the work surface 18.

  The advantage of the present invention is that when the product 10 comes into contact with the work environment, the polymer microelements 16 ′ on the work surface 18 of the product 10 open and are harder than the polymer microelements 16 embedded in the secondary surface 24. It is to reduce. Further, the reduced polymer microelements 16 'have less support for the portion 15 of the polymer matrix 14 surrounding the reduced hardness microelements, thereby increasing the effective hardness of the surrounding portion 15 of the polymer matrix. Decrease. Thus, at least two levels of hardness are made of the product 10 with the work surface 18 generally softer than the secondary surface 24.

  Another advantage of the present invention is that as the work surface 18 of the product wears out, such as by contact with the surface of the workpiece or the work environment, the secondary surface 24 immediately adjacent to the work surface 18 becomes a new work surface. One hardness level is continuously regenerated, which allows for a more uniform and consistent polishing of the workpiece and a more even wear of the pad 12.

  Hereinafter, a specific example of the product 10 will be described. In addition, this invention is not limited to the following examples.

[Specific product example 1]
The polymer matrix was about 66 ° C. ( about 150 ° F. ) and 2997 g of Uniroyal Adiprene L-325 polyether urethane urethane prepolymer of 768 g of “Curene® 442” (4 4'-methylene-bis [2-chloroaniline] "MOCA"). At this temperature, the urethane / polyfunctional amine mixture has a pot life ("low viscosity region") of about 2.5 minutes.

  During this low-viscosity region, 69 g of Expancel 551 DE hollow polymer microspheres having void spaces containing gas at pressures greater than atmospheric pressure were obtained from the polymer mixture and Rodel Inc. Using high speed shear compounding and mixing equipment, the microspheres were compounded at 3450 rpm to distribute the entire polymer evenly throughout the polymer mixture, and the mixture was transferred to a conventional mold during the low viscosity region and 15 for gelation. Left for a minute.

The mold was then placed in a curing oven, such as commercially available from Koch Oven Corporation. The mixture was cured in an oven at about 93 ° C. ( about 200 ° F. ) for about 5 hours. After curing, power to the oven was turned off and the mixture was allowed to cool in the oven for about 4-6 hours until the temperature of the molded product 10 was about 21 ° C. ( about 70 ° F. (room temperature) ) . The molded product was then cut to form a polishing pad. The resulting average distance between the microspheres of the polishing pad 12 appears to be between about 75 μm and about 300 μm.

  As shown in FIG. 4, when a pad is used to planarize a typical semiconductor device having a pattern or chip with a spacing of about 1 mm, the planarization rate (μm-1) is an Expancel. A 20 mil thick urethane pad with embedded microspheres (indicated by a square symbol) is four times larger than a similar urethane pad without a microsphere (indicated by a circle symbol). In other words, FIG. 4 shows that using a urethane pad with embedded microelements according to the present invention flattens the device four times faster than a urethane pad without microelements.

  As shown in FIG. 10, the specific gravity of the molded product decreases as the microsphere flow rate increases. In general, it is preferred that the specific gravity of the pad be from about 0.75 to about 0.8, which corresponds to an Expancel microsphere flow rate of about 53 grams per minute.

[Specific product example 2]
Unipolymer Adiprene L-325 urethane with a polymer matrix of 2997 g was mixed with 768 g of “Cureene® 442 MOCA” and the urethane polymer was mixed with Air Products and Chemicals, Inc. (Allentown, Pa.) Products and Chemicals Corporation) were prepared by high-speed shear blending with 87 g of partially acetylated polyvinyl alcohol powder available commercially. During the low viscosity region (2.5 minutes), the mixture is poured into the mold in a manner similar to that of the product of Example 1 and cured in an oven at about 107 ° C. ( about 225 ° F. ) for about 6 hours on gelling. And wandered to room temperature. It seems that basically no reaction has occurred between the OH group of the polyvinyl alcohol and the isocyanate group of the urethane prepolymer because of the very fast reaction with the amine groups of the urethane (MOCA amino groups).

[Specific product example 3]
A polymeric matrix was prepared in a manner similar to that of Example 1 by mixing 3625 g of Adiprene L-213 with 930 g of “Curene® 442 MOCA”. During the low viscosity region (approximately 2.5 minutes), 58 g of pectin powder, commercially available from Freeman Industries Inc., Tuckahoe, New York, is high speed shear compounded with urethane polymer to mix the pectin powder with the entire urethane mixture. Evenly distributed. During the low viscosity region (2.5 minutes), the resulting urethane / pectin mixture is injected into the mold in a manner similar to that shown in Example 1 and is about 107 ° C ( about 225 ° C) on gelling. F ) for about 6 hours, cured, wrinkled and processed.

[Example 4 of product]
Adiprene L-325 with a polymeric matrix of 2997 g is commercially available from BASF Chemicals Corp. of Parisipany, NJ or GAF Chemicals Corp. of Wayne, NJ Prepared by mixing with 65 g of polyvinylpyrrolidone powder for about 30 seconds to make a homogeneous formulation. “Curene® 442MOCA” (768 g) is melted at a temperature of about 212-228 ° F. and high speed shear compounded with a urethane / polyvinylpyrrolidone mixture between the low viscosity regions, ie, before 2.5 minutes have elapsed. Was injected into the mold. The resulting mixture is gelled in the same manner as shown in Example 1 and then heated at about 107 ° C. ( about 225 ° F. ) for about 6 hours and cut into a polishing pad shape. It was.

[Specific product example 5]
A polymer matrix was prepared by mixing 3625 g of “Adiprene L-213” with 930 g of “Cureene® 442 MOCA”. 65 g of white, free-flowing hydroxyethylcellulose (available commercially from Union Carbide Chemicals and Plastics Corp., Danbury, Conn.) During the low viscosity range is a urethane mixture It was formulated. Hydroxyethylcellulose is insoluble in organic solvents, but dissolves in hot or cold water. The composite mixture was then processed in a manner similar to that shown in Example 1.

  In another example best shown in FIGS. 5-9, the work surface 18 of the product 10 may further be provided with mini- or macro-sized patterns or grooves 26 comprising concave and / or convex portions or processing structures 28. The grooves 26 can be formed in at least a portion of the work surface 18 by mechanical grooving methods such as machining, embossing, turning, polishing, copying and laser machining. One skilled in the art will appreciate that the grooves 26 can be formed by a variety of other mechanical or chemical methods such as etching.

  Grooving the work surface 18 can expose up to 50% or more of the surface to facilitate removal of wrinkles during polishing. In addition, the grooving of the work surface 18 enhances the polishing action by increasing the number of microelements 16 'exposed to the work environment. The grooves 26 can be formed in various patterns, contours, grooves, spirals, radii, dots, or any other shape as desired. Grooving the work surface 18 of the pad 12 results in a series of hardness changes on a microscale. For example, the processed structure 28 can be shaped to form a cone or tip with a hard core and a soft outer surface in addition to the harder subsurface 24.

  Preferably, the work structure 28 is spaced at a distance between about 0.1 mm and about 10 mm and has a depth between about 1 mm and about 10 mm. In general, it is preferred that the processed structure 28 has a length that is less than about 1000 times the average diameter of the polymeric microelements 16 in the first dimension. It is also preferred that the processed structure 28 has a depth that is less than about 2000 times the average diameter of the polymeric microelements 16.

  As best shown in FIGS. 5 and 6, the work surface 18 can comprise a mini-sized groove that includes a processing structure 28 having a width of between about 1000 μm and 5 mm. Although the mini-sized grooves shown in FIGS. 5 and 6 are eccentric circular patterns, those skilled in the art will appreciate that the mini-sized grooves can be spirals or other patterns including those described above.

  As best shown in FIGS. 7 and 8, the work surface 18 may comprise macro-sized grooves that include a machining structure 28 each having a width greater than about 5 mm. As shown in FIGS. 7 and 8, although the mini-sized grooves are generally rectangular grids, those skilled in the art will understand that the mini-sized grooves can be formed in any pattern, including those described above, as needed. I can do it.

  Macro-sized and mini-sized grooves can be formed by typical machining methods such as embossing, turning, polishing, replication, and laser machining, and various other methods well known to those skilled in the art.

[Example 6 of the product]
Using a standard lathe and a single tip tool, each of the circular and square grid patterns is superimposed on the work surface 18 vacuum mounted to the lathe or milling machine rotating plate to provide the work surface shown in FIGS. 18 was cut. Conventional milling machines with custom cutting combs with ganged cutting tools or serrated teeth spaced at regular intervals are used to machine the working surface 18 into the desired pattern. It was.

  As best shown in FIG. 5, annular mini-sized grooves are applied to the polishing pad to form grooves having a pitch of 1.397 mm (0.055 ″), each groove being 0.356 mm. (0.014 ″) depth. The shape of the groove is a buttress thread with a 60 degree slope towards the inner diameter of the pad, as shown in FIG.

  The square lattice macro-sized grooves 28 shown in FIGS. 7 and 8 are machined on a horizontal milling machine and are 0.813 mm (0.032 ″) wide and 0.635 mm (0.025 ″) deep grooves. This groove defines a 6.35 mm (0.025 ″) processed structure 28.

  As best shown in FIG. 9, the work surface 18 can also be provided with mini-sized grooves that include processing features 28 having a width between about 1000 μm and 5 mm, produced by the use of a carbon dioxide laser. Preferably, the micro-sized grooves are made in the form of a debris pattern on the work surface 18. The “fractal pattern” as defined herein means a repetitive pattern having repetitive machining structures with different machining structures. The debris pattern can be a deterministic or non-deterministic mathematical expression such as the Gosper Island variant ("Gosperpattern") (shown in FIG. 9) of the Koch Island & Lake debris pattern. formulas). Although suitable debris models include round, spherical and Swiss cheese tremas, those skilled in the art will appreciate that other suitable debris patterns can be used in accordance with the present invention as needed. Preferably, the debris pattern is chaotic or random.

[Specific product example 7]
As best shown in FIG. 9, grooves or mini-sized grooves were processed into the polishing pad 12 using a typical carbon dioxide laser having a 100 watt continuous wave output. The power rating, power, and beam focus were selected to cut a groove having a depth of about 0.458 mm (0.018 ") and a width of about 0.127 mm (0.005") or less. The mini-size groove was the Gosper Island variant of the Koch Island & Lake fragment pattern described above. The debris pattern image was electronically read and programmed into a conventional computer numerical controller that controls the movement of the laser beam to form a debris pattern on the work surface 18 of the pad 12. An adhesive mask was placed on the pad to prevent accumulation of gas marks. This adhesive shield also reduced the attendant minor that welded to the edge of the groove.

  Alternatively, or additionally, an isolated “mesa” pattern can be embossed on the work surface 18 to form a mini-sized groove. For example, using a conventional 30-ton press, a pressure of about 25 tons can be applied to emboss a mini-size groove on the work surface 18 of the pad 12. Heat can be applied to enhance the relief effect.

  A method according to the present invention for planarizing the surface of a semiconductor device utilizing an article 10 or less according to the present invention is generally described below.

  1-3, the method generally comprises an initial stage of providing a product 10 or 110 comprising a polymeric matrix 14. The polymer matrix 14 is impregnated with a plurality of polymer microelements 16. Details of the steps of providing the polymer matrix 14 and impregnating the matrix 14 with the microelements 16 have been described above, and further discussion thereof is considered unnecessary and seems to be unlimited. Preferably, the working surface 18 of the product 10 or 110 is grooved to form a work structure 28 to provide an enlarged work surface, and if the work surface is generally flat, the microelements that are not normally exposed are removed from the work environment. Shall be exposed.

  The method provides that at least a portion of the work surface 18 of the product 10 or 110 is harder than the polymer microelement 16 located on the adjacent subsurface 24 where the polymer microelement 16 'in the work surface 18 of the product 10 or 110 is adjacent. The method further includes contacting the work environment so as to reduce. For example, a portion of the shell 20 of at least some of the polymer microelements 16 located in the vicinity of the work surface 18 may be sliced, ground, cut and drilled by at least one method, or chemically. A part of the polymer microelement 16 ′ of the work surface 18 is opened by changing or softening a part, so that the hardness of the microelement 16 located on the sub-surface 24 is reduced. Details regarding how the stiffness of the polymeric element 16 ′ on the work surface 18 can be reduced have been described above, and further discussion thereof is deemed unnecessary and seems unlimited.

  The method further comprises contacting a surface of a semiconductor device (not shown) (also not shown) with at least a portion of the work surface 18 of the product such that the surface of the semiconductor device is sufficiently planarized. To do. Product 10 or polishing pad 12 is attached to a conventional polishing machine as is well known to those skilled in the art. Preferably, the work surface 18 is oriented generally parallel to the surface of the semiconductor device to be planarized, for example with linear or circular sliding contact so as to planarize or grind the surface of the semiconductor device as required. Shall be moved.

  As the working surface 18 of the pad 12 is ground in sliding contact with the surface of the semiconductor device, a portion of the minor surface 24 is exposed and the microelements 16 on the minor surface 24 are ground or undergo chemical changes. Alternatively, it is softened to form a new work surface 18 having physical properties similar to the previously ground work surface. Accordingly, the work surface 18 that contacts the surface of the semiconductor device is substantially continuously regenerated, providing a consistent planarization or polishing action to the surface of the semiconductor device.

  A method according to the present invention for regenerating a work surface 18 of a product according to the present invention is generally described below.

  In FIG. 11, the method includes providing an article 410 or pad 12 comprising a polymeric matrix 14 and impregnating the matrix 14 with a plurality of polymeric microelements 16. Details of the stage of forming the product 10 have been described above, and further discussion is considered unnecessary and seems unlimited.

  The method opens at least a portion of the shell 20 of at least some of the polymeric microelements 16 located near the work surface 18 so that the open microelements 16 ′ are less rigid than the microelements 16 of the secondary surface 24. The method further includes the step of: The step of opening the polymer microelement can comprise slicing, grinding, cutting and drilling a portion of each shell 20 of the microelement 16. As best shown in FIG. 11, the shell 20 of the microelement 16 ′ on the work surface 18 is perforated by a combined pommelgation and drilling device 30, a portion of which is shown in cross section in FIG. 11. I can dawn. The apparatus 30 can be formed from any material that has sufficient rigidity to drill into the work surface 18 and the microelements 16, such as stainless steel, aluminum, or other metals. The apparatus 30 includes a plurality of sharp tools or needles 32 that drill holes in at least a portion of the shell 20 of the polymeric microelement 16 located near the work surface 18.

  In addition to the needle 32, the device 30 comprises at least one, preferably a plurality of pads 34, that prevent the needle 32 from being drilled too deeply into the work surface 18. Preferably, the needle 32 is drilled in the working surface 18 at a depth of about 60 μm, but those skilled in the art can take any depth in which the drilling depth of the device 30 increases or decreases from 60 μm as needed. I can understand that. For example, a long needle 32 can be used to drill a hole in the working surface 18 that reaches a depth greater than 60 μm.

  One skilled in the art will appreciate that the microelements 16 can be opened multiple times or the pads 12 can be drilled as needed.

  In another example, at least a portion of the shell 20 of the polymeric microelement 16 located in the vicinity of the work surface 18 is a high height where the partially altered polymeric microelement 16 on the work surface 18 is embedded in the secondary surface 24. It is chemically changed or softened by the working environment so that the hardness is reduced as compared with the molecular microelement 16. For example, the polymeric microelement 16 can be formed from water-soluble cellulose ether comprising methylcellulose or propylmethylmethylcellulose that is at least partially dissolved when contacted with a working environment containing water.

  From the foregoing description, the present invention reduces the effective stiffness of a product that changes the surface of a workpiece, such as a semiconductor device, and a polymeric microelement located on a portion of the work surface of such a product, such as It can be seen that it comprises a method of reclaiming the work surface of a product and planarizing the surface of the semiconductor device using such a product. This product can be used to polish or planarize substrates and other workpieces more quickly and uniformly.

  The polishing pad is impregnated with a plurality of polymer microelements that are used in conjunction with the polishing slurry to polish or planarize the workpiece and do not substantially polish the surface of the workpiece itself. There are also products made of a polymer matrix (except those in which the polymer microelements have void spaces containing gas at a pressure greater than atmospheric pressure). A product having a work surface and a sub-surface adjacent to the work surface impregnated with a polymer microelement having a plurality of void spaces in the polymer matrix is brought into contact with the work environment, thereby adjacent to the work surface. At least a part of the shell of the polymer microelement located at the top is opened, the polymer microelement opened is less hard than the polymer microelement embedded in the secondary surface, and the work surface of the product is regenerated Like to do.

  The shell of the polymer microelement may be opened by any one of thinning, grinding, cutting and drilling of a part of the shell.

  The polymer microelement located in the vicinity of the work surface is less hard than the polymer microelement embedded in the sub-surface when at least a part of the shell is chemically changed by the work environment. can do.

  A portion of the work surface can be grooved to reduce stiffness when in contact with the work environment.

  Further, the processed product can be a semiconductor device.

  Those skilled in the art will recognize that other modifications can be made to the examples without departing from the broad inventive idea of the above examples. Accordingly, it is to be understood that the invention is not intended to be limited to the disclosed examples, but is intended to encompass all modifications within the spirit and scope of the invention as defined by the appended claims.

The schematic sectional drawing of the product used by this invention. The schematic sectional drawing of the change aspect of the product used by this invention. The schematic sectional drawing which shows the state expanded when the micro element in the product work surface of the change aspect of the product used by this invention contacted the working environment. FIG. 5 is a graph of the planarization rate as a function of interpattern distance at the surface of a typical semiconductor device. The schematic diagram of the change aspect of the mini size grooved pad used by this invention. FIG. 6 is an enlarged partial cross-sectional view of the pad taken along line 6-6 of FIG. The schematic diagram of the change aspect of the macro size grooved pad used by this invention. FIG. 8 is an enlarged partial cross-sectional view of the pad taken along line 8-8 of FIG. A variation of the mini-sized grooved pad of the fractal pattern used in the present invention. FIG. 5 is a bar graph showing the specific gravity as a function of the flow rate of the microspheres of the product used in the present invention. 1 is a schematic diagram of a device that pierces a part of a shell of a microelement on a work surface of a product used in the present invention by pommelgate. FIG.

Explanation of symbols

10 Products 18 Work surface 16 Polymer microelement 20 Shell 24 Subsurface 22 Void space

Claims (5)

A polishing pad having a work surface for planarizing a multilayer electronic device comprising:
The polishing pad includes a polymer matrix and a soluble polymer microelement that is uniformly embedded in the polymer matrix in the depth direction, where the polymer microelement includes polyvinyl alcohol, pectin, polyvinyl Pyrrolidone, hydroxyethyl cellulose, methyl cellulose, hydropropyl methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, polyacrylic acid, polyacrylamide, polyethylene glycol, polyhydroxyether acrylate, starch, maleic acid copolymer, polyethylene oxide and Selected from the group consisting of polyurethane,
The work surface of the polishing pad is provided with a groove,
When the work surface is worn in the process of flattening the multilayer electronic device, a new work surface is regenerated.
Polishing pad.   The polishing pad of claim 1, wherein the grooves are provided to form spirals, dots, square grids, concentric circles, or debris patterns.   The polishing pad according to claim 1 or 2, wherein the groove has a depth smaller than 2000 times the average diameter of the polymer microelements. The polishing pad according to claim 1, wherein the soluble polymer microelement is starch . The polishing pad according to claim 1, wherein the polymer matrix is urethane.

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