Source: http://www.google.com/patents/US7104868?dq=6,411,947
Timestamp: 2014-08-31 08:59:24
Document Index: 683217126

Matched Legal Cases: ['art 58', 'art 58', 'art 58', 'art 58', 'art 58', 'art 58', 'art 58', 'arts 79', 'art 79', 'art 79', 'arts 79', 'arts 79', 'art 82', 'art 82']

Patent US7104868 - Turning tool for grooving polishing pad, apparatus and method of producing ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsDisclosed is a turning tool for cutting circumferential grooves into a surface of a polishing pad formed of a resin material and utilized for polishing semiconductor devices. The turning tool comprising a cutting part arranged to have a tooth width within a range of 0.005�1.0 mm, a wedge angle within...http://www.google.com/patents/US7104868?utm_source=gb-gplus-sharePatent US7104868 - Turning tool for grooving polishing pad, apparatus and method of producing polishing pad using the tool, and polishing pad produced by using the toolAdvanced Patent SearchPublication numberUS7104868 B2Publication typeGrantApplication numberUS 10/830,567Publication dateSep 12, 2006Filing dateApr 23, 2004Priority dateDec 19, 2001Fee statusPaidAlso published asUS6869343, US7017246, US7140088, US20030119425, US20040198199, US20040198204, US20040209551, US20060137170Publication number10830567, 830567, US 7104868 B2, US 7104868B2, US-B2-7104868, US7104868 B2, US7104868B2InventorsTatsutoshi SuzukiOriginal AssigneeToho Engineering Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (17), Non-Patent Citations (1), Referenced by (3), Classifications (31), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetTurning tool for grooving polishing pad, apparatus and method of producing polishing pad using the tool, and polishing pad produced by using the toolUS 7104868 B2Abstract Disclosed is a turning tool for cutting circumferential grooves into a surface of a polishing pad formed of a resin material and utilized for polishing semiconductor devices. The turning tool comprising a cutting part arranged to have a tooth width within a range of 0.005�1.0 mm, a wedge angle within a range of 15�35 degrees, and a front clearance angle within a range of 65�45 degrees. A polishing pad effectively formed by using the turning tool, and an apparatus and a method of producing such a polishing pad by utilizing the turning tool are also disclosed.
1. A method of producing a polishing pad made of a resin material, comprising the steps of:
positioning a turning tool comprising a cutting part arranged to have a tooth width within a range of 0.005�1.0 mm, a wedge angle within a range of 15�35 degrees, and a front clearance angle within a range of 65�45 degrees, relative to a base for said polishing pad formed of said resin material;
rotating said cutting part of said turning tool relative to said base for said polishing pad about an axis of said base for said polishing pad, for cutting circumferential grooves into a surface of said base such that radially inner most one of said circumferential grooves has a radius of curvature of 10 mm or smaller.
2. A method of producing a polishing pad according to claim 1, wherein said turning tool comprises a plurality of cutting parts which are arranged in a predetermined direction with a pitch within a range of 0.2�2.0 mm, and wherein said circumferential grooves comprises a multiplicity of generally concentric annular grooves, said method further comprising the steps of:
simultaneously cutting a plurality of said generally concentric grooves into said surface of said base for said polishing pad such that radially inner most one of said multiplicity of generally concentric annular grooves has a radius of curvatures of 10 mm or smaller.
3. A method of producing a polishing pad according to claim 2, wherein said plurality of cutting parts are arranged in a predetermined direction with regular pitches.
4. A method of producing a polishing pad according to claim 1, wherein said turning tool comprises a plate-like shaped tool tip having a plurality of cutting parts integrally formed at one of edge portions thereof so as to protrude outwardly from said one of said edge portions and arranged in a predetermined direction with a pitch within a range of 0.2�2.0 mm, and wherein said circumferential grooves comprises a multiplicity of generally concentric annular grooves, said method further comprising the steps of:
5. A method of producing a polishing pad according to claim 4, wherein said turning tool comprises a plurality of said plate-like shaped tool tips, said tool tips being fixedly arranged with each other so as to aligned in a width direction thereof such that said cutting parts of said tool tips cooperate to form a multiplicity of cutting parts.
6. A method of producing a polishing pad according to claim 5, wherein said turning tool further comprises a predetermined tool-tip holder to which said plurality of said plate-like shaped tool tips are detachably fixed, said tool tip holder and said plurality of tool tips cooperate to constitute a tool unit.
7. A method of producing a polishing pad according to claim 1, wherein said turning tool comprises a plurality of cutting tips each having a cutting part and detachably fixed to each other so that cutting parts of said plurality of cutting tips cooperate to form a plurality of cutting parts which are arranged in a predetermined direction with a pitch within a range of 0.2�2.0 mm, and wherein said circumferential grooves comprises a multiplicity of generally concentric annular grooves, said method further comprising the steps of:
8. A method of producing a polishing pad according to claim 1, wherein said turning tool is adapted to cut said circumferential grooves into said surface of said base for said polishing pad at a feed per revolution of 0.005�0.05 mm/rev in a depth direction of said base.
9. A method of producing a polishing pad according to claim 1, further comprising the steps of:
blowing ionic fluid toward a vicinity of said cutting parts to neutralize said base of said polishing pad and chips which are electrically charged due to execution of said step of cutting by the turning tool said circumferential grooves into said surface of said base for said polishing pad.
This is a Division of application Ser. No. 10/026,504 filed Dec. 19, 2001 now U.S. Pat. No. 6,869,343.
The present invention relates to a turning tool for producing a polishing pad made of a resin material and usable in the fabrication of semiconductor devices, especially for chemical mechanical polishing (CMP) executed for planarizing surfaces of semiconductor wafers or devices. The present invention further relates to a polishing pad effectively formed by using the turning tool, and an apparatus and a method of producing such a polishing pad by utilizing the turning tool.
Another known example of conventionally employed polishing pad for CMP is disclosed in US Patent Publication Nos. U.S. Pat. No. 5,921,855 and U.S. Pat. No. 5,984,769. The disclosed polishing pad is provided with a plurality of annular grooves open in its polishing surface. The plurality of annular grooves are arranged in a generally concentric or coaxial relationship with each other, and are dimensioned to have a width of not smaller than 0.38 mm and a depth of not smaller than 0.51 mm, and are uniformly spaced with a pitch of 2.29 mm in a radial direction of the polishing pad. However, the disclosed polishing pad suffers from inherent structural problems, namely, difficulty in forming grooves extending in a circumferential direction in the polishing pad and difficulty in ensuring a sufficient dimensional accuracy of the grooves.
FIG. 1A is an front elevational view of a grooving machine constructed according to one preferred embodiment of the present invention, and
FIG. 1B is an plane view of the grooving machine of FIG. 1A, while
FIG. 1C is a side elevational view of the grooving machine of FIG. 1A;
FIG. 4A is a plane view of a platen of the grooving machine of FIG. 1, and
FIG. 4B is a cross sectional view of the platen of FIG. 4A taken along line B�B of FIG. 4A;
FIG. 5A is a plane view of a suction plate of the grooving machine of FIG. 1,
FIG. 5B is an axial cross sectional view of the suction plate,
FIG. 5C is a fragmentally enlarged view of the suction plate,
FIG. 5D is an enlarged view of a X portion of FIG. 5C, and
FIG. 5E is an enlarged cross sectional view taken along line E�E of FIG. 5D;
FIGS. 6A and 6B are a front and a side views of the grooving machine of FIG. 1A, which are depicted for explaining a primary pan of the grooving machine of FIG. 1A;
FIG. 10 is a fragmentally side elevational view of the grooving machine of FIG. 1A, which shows one operating state 4 the grooving machine in which a milling tool is attached to the tool holder;
FIG. 15A is a front elevational view of an ion blowing device used in the grooving machine of FIG. 1 for neutralizing charged components of the grooving machine, and
FIGS. 15B and 15C are a side and a bottom elevational view of the ion blowing device, respectively;
FIGS. 16A and 16B are a front and a side views of a turning tool having a single culling part, which is usable in the grooving machine of FIG. 1;
FIGS. 17A, 17B, and 17C are bottom, side and front views of a turning tool having a plurality of cutting parts, which is usable in the grooving machine of FIG. 1;
FIG. 21 is an explanatory view showing one example of operation state of the grooving machine of FIG. 1, in which a plurality of tool chips of FIG. 18 are fixed to the tool bolder;
FIG. 22A is an enlarged side view of one example of a multi-edged tool tip in which a plurality of cutting parts are laminated one another, and
FIG. 22B is an enlarged front elevational view of the multi-edged tool of FIG. 22A;
FIG. 23A is an enlarged side view of another example of a multi-edged tool tip in which a plurality of cutting edges are laminated one another, and
FIG. 23B is an enlarged front elevational view of the tool tip of FIG. 23A;
FIG. 24A is a side view of one example of a cutting device usable in the grooving machine of FIG. 1,
FIG. 24B is a front elevational view of the cutting device, and
FIG. 24C is a cross sectional view of the cutting device, taken along line C�C of FIG. 24B;
FIG. 25A is a plane view of one example of a milling cutter attachable to the milling tool of FIG. 10, and
FIG. 25B is a fragmentally enlarged view of the milling cutter of FIG. 25A;
FIG. 26A is a plane view of one example of a drill attached to a drill unit of FIG. 11, and
FIG. 26B is an exploded view of a major cutting edge portion of the drill of FIG. 26A;
FIG. 30 is still another example of polishing pad of foamed urethane according to examples 1 and 2 by using the grooving machine of FIG. 1 equipped with the turning tool of FIG. 17:
FIG. 31 is a fragrnentally enlarged view in axial cross section of the polishing pad of FIG. 30;
FIG. 32A is a microscopic photographic view of 30 times magnification and
FIG. 32B is a microscopic photographic view of 100 times magnification, which shows a cross sectional shape of grooves of one example of a polishing pad of the present invention, which grooves are formed by using the turning tool of the present invention;
FIG. 33A is a microscopic photographic view of 30 times magnification and
FIG. 33B is a microscopic photographic view of 100 times magnification, which shows a cross sectional shape of grooves of a comparative example of a polishing pad;
The hollow center shaft 17 has a bore 17 b serving as an air passage. The bore 17 b is held in fluid-tight communication at its upper end with a plurality of communication holes 1 a formed through the central portion of the circular platen 1, and at its lower end with an air hose 28 of the suction blower 25 via a coupling 27 supported by a support 26 fixed to a seat portion 3 b of the bed 3. In this condition, the vacuum generated in the suction blower 25 is applicable to the rear surface of the foamed urethane pad placed on the upper surface of the circular platen 1 through the bore 17 b of the center shaft 17 and the communication holes 1 a of the circular platen 1. Therefore, the vacuum application needed for holding the foamed urethane pad on the surface of the circular plate 1 can be executed during the rotation of the center shaft 17. In this respect, the upper open end of the communication holes 1 a are closed by a suction plate 16 which is placed on the upper surface of the circular platen 1. As shown in FIG. 5, the suction plate 16 is formed with a plurality of suction holes in the form of air holes 16 a and grooves 16 b, so that the vacuum is evenly applied in the upper surface of the suction plate 16 through the communication holes la and the air holes 16 a and the grooves 16 b, thus assuring firmly holding of the foamed urethane pad 15 on the surface of the suction plate 16. As is understood from the aforementioned description, the position holding member 38, the drive motor 21 and the suitable power transmittal members cooperates to form a drive mechanism adapted to rotate the circular platen 1 and place the circular platen 1 at a suitable angular position, in the present embodiment.
Referring next to FIG. 13, there is shown a block diagram schematically showing a control system of the NC device 102 adapted to control operation of the grooving machine. Described in detail, the NC device 102 includes data input section 101, a central processing unit (CUP) 103, a data storage section 104 and an I/O interface. Upon starting the grooving process under control of the NC device 102, a tool command representing a kind of required tool, and dimensional information of the required tool is applied to the numerical control device 102 through the data input section 101. The required tool is suitably determined depending upon a desired groove pattern, e.g., a grid pattern or a generally concentric annular groove pattern. This tool command is stored in the data storage section 104 via the CPU 103. Once an operation command is applied from the input section 101, the CPU 103 controls operation of the respective motors 13A, 13B, 21, 40, 47, 48, and the cutting device 77 according to a suitable processing program with reference to data stored in the storage section 104, so that the operations of the circular platen 1, the gate-shaped column 11, the saddles 8A, 8B, the tool rests 18 ,19 and the milling cutter unit 59, the drill unit 65 are accurately controlled. Each motor is equipped with an encoder. An amount of rotation of the motor detected by the encoder is applied to the NC device so that the NC device controls the operation of the grooving machine in a feedback control fashion. The CPU 103 also controls operation of the suction blower 25, the position holding member 38 of the circular platen 1, the ion blower 114, and a chip collection device 115.
Referring next to FIGS. 15A, 15B, there is shown the ion-blowing device 114 adapted to generate and blow positive ions formed by corona discharge. The ion-blowing device 114 includes a compressed air generator (not shown) and a blower nozzle 76, so that the generated positive ions are discharged through the blower nozzle 76 together with the compressed air. Alternatively, the positive ions are discharged through holes 71 (a), 72(a) which will be described later. This ion-blowing device 114 is disposed in a portion of the grooving machine such that a protruded open-end portion of the blower nozzle 76 is located in the vicinity of the attached cutting tool, e.g., the fixed tool 69 or the rotative tool 57 (the multi-edged tool 74 is attached in FIGS. 15A�15C by way of example). When the foamed urethane pad 15 is subjected to the grooving process, cut fragments or chips of the foamed urethane pad 15 are likely to be electrically charged due to friction between the cutting tools and the urethane pad 15, and stick to the surface of the urethane pad 15 and the cutting tools, resulting in difficulty in removing the charged chips from the surfaces of the cutting tool and the urethane pad. To cope with this problem, the ion blowing device 114 is operated to blow the positive ions on the chips stuck to the cutting tool and the foamed urethane pad 15, while the grooving process is executed for the foamed urethane pad 15, whereby the chips are effectively neutralized and removed from the cutting tool and the urethane pad 15. When the multi-edged tool 74 of the fixed tool is used for forming simultaneously a plurality of grooves on the foamed urethane pad 15, in which a plurality of cutting edges are juxtaposed to each other, it is required to evenly blow the positive ions on the respective cutting edges so that the positive ions forcedly come into collision with the charged chips. To meet this requirement, the protruded open-end portion of the nozzle 76 may be suitably arranged.
FIGS. 16A and 16B show a front and a side elevational view of the single edged tool 58 as one example of the fixed tool 69. FIGS. 17A�17C shows a bottom, a front and a side elevational view of the multi edged tool 74 as another example of the fixed turning tool 69. The single edge tool 58 and the multi edged tool 74 are suitably used for the grooving process in which the plurality of generally concentric annular grooves are formed on the surface of the foamed urethane pad 15.
The single edged tool 58 has a cutting part 58 a that is arranged as follows so that the single edged tool 58 is suitable for cutting a working piece made of a resin material, e.g., a foamed urethane pad. Namely, the cutting part 58 a of the single edged tool 58 has a tooth width: W1 within a range of 0.005�1.0 mm, a side clearance angle: θ1 within a range of 0�2 degrees, as shown in FIG. 16A. Further, the cutting tooth of the single edged tool 58 has a wedge angle: θ2 within a range of 30�35 degrees, a rake angle: θ3 within a range of 10�20, and a front clearance angle θ4 within a range of 45�55 degrees, as shown in FIG. 16B. These angles of respective parts of the cutting part 58 a of the single edged part 58 a are determined taking into account a problem of interface between the cutting part 58 a and walls of the foamed grooves and a required strength of the cutting part 58 a. Preferably, the single edged part 58 a is made of a rigid material, such as hard metal, high speed steel, carbon steel, ceramics, cermet, and diamonds.
Referring next to FIGS. 24A�24C, there are respectively shown a side elevational view, a front elevational view and a cross sectional view taken along line C�C of FIG. 24B of the cutting device 77 which is adapted to be mounted on the tool rest 18 (19) disposed on the saddle 8A (8B) of the cutting machine constructed according to the present embodiment. The cutting device 77 is operable to cut primary peripheral portion of the foamed urethane pad 15 to shape the external form of the foamed urethane pad 15 desirably. More specifically described, the cutting device 77 includes: a base 78; a fourth guide rails 63A, 63B disposed on the base 78 so as to extend parallel to each other in the Z-axis direction; a tool rest 64 disposed on the base 78 via the pair of fourth guide rails 63A. 63B so as to be movable in the Z-axis direction; a cutting tool holder 66 mounted on the tool rest 64; and a power source 62 disposed on the base 78 so as to generate a drive power by which the tool rest 64 is moved in the Z-axis direction. A cutting tool 61 is fixed to the cutting tool holder 66 such that a base portion of the cutting tool 61 is fitted into a cutting tool base 83 formed in the cutting tool holder 66, while being supported by the a pair of tool supports 65 with its protruding end portion supported by a stopper pin 80. An output member of the power source 62 is connected to a support member 67 disposed on the tool rest 64 via a connecting metal member 68, thus transmitting output power of the power source 62 to the tool rest 64. Thus, the cutting tool 61 is driven in the Z-axis direction. It should be understood that the power source 62 may comprises a piston-cylinder mechanism of pneumatics type or hydraulic type, or a solenoid-type actuator. It should be further understood that the cutting tool 61 may otherwise be constituted by a suitable turning tool for assuring further improved cutting ability of the cutting device 77.
FIG. 25A shows a front view of one example of a milling cutter 81 for forming a fine groove, which is fixed to the grooving milling cutter unit 59. FIG. 25B shows an enlarged view of cutting parts 79 of the milling cutter 81 of FIG. 25A. The milling cutter 81 is a thin circular disk member, which has a center hole 81 a formed therethrough and a plurality of cutting part 79 integrally formed in its outer peripheral portion such that the plurality of cutting part 79 are arranged in a circumferential direction of the grooving milling cutter 81 with a uniform pitch. Each of the cutting parts 79 is dimensioned to have a wedge angle: θ5 within a range of 20�45 degrees, since the wedge angle: θ5 smaller than 20 degrees may cause undesirable shortening of the life of the grooving milling cutter 81, while the wedge angle: θ5 larger than 45 degrees may cause deterioration of cutting capability of the cutting tooth 79. Further, the each cutting parts 79 is dimensioned to have a rake angle: θ6 within a range of 30�40 degrees, more preferably at around 30 degrees, since the rake angle: θ6 smaller than 30 degrees may cause deteriorated stability of the milling cutter 81, while the rake angle: θ6 larger than 40 degrees may cause deterioration of cutting capability of the cutting tooth 79. Yet further, the each cutting tooth 79 is dimensioned to have a side cutting edge angle within a range of 0�2 degrees and a tooth width within a range of 0.3 mm�2.0 mm. The thus formed milling cutter 81 is disposed radially outwardly on a tool shaft formed on the lower portion of the grooving milling cutter unit 59 and rotated in a predetermined circumferential direction by the drive motor 126. The number of the milling cutter 81 fixed to the tool shaft is not particularly limited. For instance, a plurality of grooving milling cutters 81 may be fixed to the tool shaft with constant intervals within a range of 0.1 mm or more, so that a plurality of grooves arranged in a grid pattern are formed on the foamed urethane pad 15 with improved efficiency.
FIG. 26A shows a front elevational view of one example of a drill 82 to be fixed to the drill unit 65, and FIG. 26B shows an exploded view of a cutting part 82 a of the drill 82. As shown in FIG. 26A, the drill 82 has a diameter: D1 within a range of 0.5 mm�1.5 mm and a length: L1 within a range of 20�30 mm. As shown in FIG. 26B, the cutting part 82 a of the drill 81 includes two cutting edges 83, 83. The end edge portion of the drill 82 has a cone angle θ8 within a range of 55�65 degrees, more preferably at around 60 degrees, thus assuring a smooth inserting of the drill 81 into the work piece. A helix angle: θ7 of the two cutting edges 83, 83 is arranged to be held within a range of 1�10 degrees, preferably at about 5 degrees. This arrangement makes it possible to gradually cut a part of the foamed urethane pad 15 located around the edge of the drill 82, thereby forming a desired hole having a predetermined diameter. The number of the drill 82 fixed to the drill unit 65 is not particularly limited. For instance, a plurality of drill 82 may be fixed to the drill unit 65 to form a multi-shaft type drill unit, so that a plurality of holes are formed into the foamed urethane pad 15 with improved efficiency.
Referring next to FIGS. 27A, 27B, there is shown a polishing pad fabricated according to one preferred embodiment of the invention by way of example. The polishing pad is formed by cutting a multiplicity of generally concentric grooves into the surface of the foamed urethane pad 15 having a thickness: T1 within a range of 1.0 mm�2.0 mm. The generally concentric grooves have a width: W1 within a range of 0.005�1.0 mm, a depth: D1 within a range of 0.2�2.0 mm, and a pitch: L2 within a range of 0.2�2.0 mm. For producing the polishing pad of the present invention, initially, the single-edged cutting tool 58 or the multi-edged cutting tool 74 is fixed to the tool rest 18(19), while a base for desired polishing pad, e.g., the foamed urethane pad 15 is placed on the suction plate 16 of the circular platen 1. Preferably, the foamed urethane pad 15 is shaped to have a circular-disk shape identical in size with the circular platen 1 in advance, by cutting. The cutting of the foamed urethane pad 15 may be executed by means of cutting device 77 fixed to the tool rest 18 (19). In the case where the foamed urethane pad 15 has a diameter smaller than the suction plate 16, an annular covering member may be placed on the outer peripheral portion of the suction plate 16 located radially outward of the foamed urethane pad 16, so that the air holes 16 a open in the outer peripheral portion of the suction plate 16 is effectively closed by the annular covering member. The suction plate 16 may be modified so that only a portion of the suction plate 16 serving for suctioning the urethane pad 15 is provided with the air holes 16 a. Alternatively, the communication grooves 16 b formed in the suction plate 16 may be partially closed so that distribution of the suction force on the suction plate 16 is divided into local sections.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5329735 *Jun 8, 1992Jul 19, 1994Charlton Thomas JSystem for forming and polishing grooves in glass panelsUS5398458Nov 19, 1992Mar 21, 1995Craftsman Marble, Granite & Tile Co.Process of manufacturing stone tile mosaics and apparatus thereforUS5921855May 15, 1997Jul 13, 1999Applied Materials, Inc.Polishing pad having a grooved pattern for use in a chemical mechanical polishing systemUS5984769Jan 6, 1998Nov 16, 1999Applied Materials, Inc.Polishing pad having a grooved pattern for use in a chemical mechanical polishing apparatusUS6238271Apr 30, 1999May 29, 2001Speed Fam-Ipec Corp.Methods and apparatus for improved polishing of workpiecesUS6241585Jun 25, 1999Jun 5, 2001Applied Materials, Inc.Apparatus and method for chemical mechanical polishingUS6464563 *May 18, 2001Oct 15, 2002Advanced Microdevices, Inc.Method and apparatus for detecting dishing in a polished layerUS6561891May 22, 2001May 13, 2003Rodel Holdings, Inc.Eliminating air pockets under a polished padUS6572445May 16, 2001Jun 3, 2003Speedfam-IpecMultizone slurry delivery for chemical mechanical polishing toolUS6602436Aug 9, 2001Aug 5, 2003Rodel Holdings, IncChemical mechanical planarization of metal substratesUS6641471Oct 20, 2000Nov 4, 2003Rodel Holdings, IncPolishing pad having an advantageous micro-texture and methods relating theretoUS6749741 *Dec 20, 2001Jun 15, 2004Uop LlcApparatus and process for prewashing a hydrocarbon stream containing hydrogen sulfideUS6783436 *Apr 29, 2003Aug 31, 2004Rohm And Haas Electronic Materials Cmp Holdings, Inc.Polishing pad with optimized grooves and method of forming sameJP2000094303A Title not availableJPH1170463A Title not availableJPS4716044A Title not availableJPS6322002A Title not available* Cited by examinerNon-Patent CitationsReference1The Science of CMP; Aug. 20, 1997; pp. 113-119; Chapter 4, Part III "Structures and Feature of th polishing pad".Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7240562 *May 17, 2005Jul 10, 2007Utah State UniversityMethod for modeling material constitutive behaviorUS7516536 *Dec 12, 2005Apr 14, 2009Toho Engineering Kabushiki KaishaMethod of producing polishing padUS7927186 *Jul 16, 2009Apr 19, 2011Asahi Glass Company, LimitedMethod for producing glass substrate for magnetic disk* Cited by examinerClassifications U.S. Classification451/28, 451/319, 83/875, 451/324International ClassificationB24B37/26, B24D13/14, B23C5/10, B23B27/04, B24D18/00, B23Q16/04, B24B1/00, B23C5/08, B23Q1/52Cooperative ClassificationB23B2210/02, B24B37/26, B23Q16/04, B23C5/10, B23B2251/50, B24D18/00, B23Q1/52, B23C5/08, B23B27/04, B23B2210/022, B23B2220/12European ClassificationB24B37/26, B24D18/00, B23B27/04, B23C5/10, B23Q1/52, B23Q16/04, B23C5/08Legal EventsDateCodeEventDescriptionApr 25, 2014REMIMaintenance fee reminder mailedDec 21, 2010CCCertificate of correctionMar 12, 2010FPAYFee paymentYear of fee payment: 4Mar 20, 2007CCCertificate of correctionRotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google