Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B37/00—Lapping machines or devices; Accessories
  • B24B37/005—Control means for lapping machines or devices
  • B24B37/0053—Control means for lapping machines or devices detecting loss or breakage of a workpiece during lapping

Definitions

• the invention relates generally to semiconductor device manufacturing and more particularly to backside chemical mechanical polishing of TSVs (through-silicon vias ) .
• CMP chemical mechanical polishing
• IC integrated circuits
• a CMP process may use abrasives and/or a chemically-active polishing solution on one or more rotating polishing pads pressed against a surface of a substrate.
• the substrate may be held in a substrate holder that rotates the substrate.
• the substrate holder may also oscillate the substrate back and forth across the surface of the rotating polishing pad(s).
• 3D packaging may be used to increase circuit functionality and/or performance in a compact footprint.
• Three-dimensional packaging may involve the interconnection of IC chips stacked on top of one another using TSVs (through silicon vias) to
• TSVs are vertical electrical conductors that extend through the substrate.
• CMP may be used in a TSV reveal process.
• a TSV reveal process may include grinding and etching a backside surface of a substrate to expose TSVs as stubs that project from the backside surface.
• a dielectric film may then be deposited on the backside surface.
• CMP may be used to remove the protruding stubs and polish the backside surface to a desired dielectric film thickness to complete the TSV reveal process.
• TSV breakage i.e., breakage of one or more stubs
• TSV breakage may occur that can ruin a substrate.
• a platen for a chemical mechanical polishing (CMP) apparatus comprises a disk-shaped base configured to receive a polishing pad on a surface thereof, the disk-shaped base having at least one through-hole, and an acoustic sensor received in the at least one through-hole and protruding from the surface of the disk-shaped base, the acoustic sensor configured to be electrically coupled to a
• a chemical mechanical polishing (CMP) apparatus configured to perform a CMP process.
• the CMP apparatus comprises a platen comprising a polishing pad, a substrate holder configured to hold a substrate to be polished, wherein the platen or the substrate holder is configured to put the substrate and the polishing pad in contact with each other, an acoustic sensor positioned proximate the polishing pad or the substrate during the CMP process, and an acoustic processor
• TSV through silicon via
• a method of monitoring and controlling a TSV (through silicon via) reveal process comprises processing a substrate using a chemical mechanical polishing (CMP) process, sensing acoustic emissions of the CMP process, and analyzing the acoustic emissions to detect TSV breakage.
• CMP chemical mechanical polishing
• FIGs. 1A-1C illustrate sequential cross-sectional views a semiconductor substrate undergoing a TSV (through silicon via) reveal process without TSV breakage according to the prior art.
• FIG. 2 illustrates a TSV without breakage
• FIG. 3 illustrates a cross-sectional view of a semiconductor substrate with TSV breakage according to the prior art
• FIG. 4 illustrates a TSV with breakage according to the prior art.
• FIG 5 illustrates a schematic partial side view of a chemical mechanical polishing (CMP) system according to embodiments .
• CMP chemical mechanical polishing
• FIGs. 6A and 6B illustrate a top view and a side cross-sectional view (taken along line 6B-6B of FIG. 6A) , respectively, of a platen and polishing pad of a CMP system according to embodiments.
• FIG. 7 illustrates a flowchart of a method of monitoring and controlling a TSV reveal process according to embodiments .
• a TSV (through silicon via) reveal process using CMP may be acoustically monitored and controlled to detect TSV breakage and to automatically respond thereto.
• CMP chemical mechanical polishing
• TSV breakage may occur more often during CMP where the TSV aspect ratio (i.e., exposed TSV stub height to TSV diameter) may be high (e.g., TSVs with small diameters) .
• High aspect ratio TSVs may allow an IC to have a greater density of chip-to-chip interconnects.
• high aspect ratio TSVs may be less rigid and thus more susceptible to breakage during a CMP process that removes exposed TSV stubs from the backside surface of a substrate .
• One or more acoustic sensors may be positioned in a CMP system to receive acoustic emissions during a CMP process.
• the one or more acoustic sensors may be coupled to, e.g., a substrate holder and/or a polishing pad platen.
• a polishing pad platen may have one or more acoustic sensors integrated therein that extend into a polishing pad mounted on the polishing pad platen.
• the acoustic emissions received by the one or more acoustic sensors may be analyzed by a system controller and/or an acoustic processor to detect TSV breakage.
• the acoustic processor may be part of a CMP system controller or, alternatively, may be a
• the system controller and/or acoustic processor may
• a CMP process may be automatically modified by, e.g., reducing a down force of a substrate or a polishing pad against the other by a predetermined amount, reducing a rotation speed of a polishing pad and/or a substrate by a predetermined amount, and/or combinations of both as may be preprogrammed in the system controller and/or acoustic processor.
• a CMP process may be automatically stopped and/or control transferred to an endpoint routine of the system controller in response to detecting TSV breakage.
• FIGs. 1A-1C illustrate a substrate 100 undergoing a TSV reveal process, which may be referred to as a BVR (backside via reveal) CMP process, in accordance with the prior art.
• FIG. 1A shows substrate 100 having a backside surface 102A that has been partially-processed by the TSV reveal process.
• Substrate 100 may have a silicon base layer 104, a metal (e.g., copper) layer 106, a plurality of TSVs 108 extending from metal layer 106 and projecting beyond silicon base layer 104, a barrier layer 110 covering TSVs 108 and metal layer 106, and a dielectric layer 112 covering backside surface 102A.
• a metal e.g., copper
• TSVs 108 may have a height H above silicon base layer 104 that may range from about 2 ⁇ to about 4 ⁇ , and may vary from TSV 108 to TSV 108.
• Substrate 100 having backside surface 102A may be received at a CMP system for further TSV reveal processing as shown in FIGs. IB and 1C.
• FIG. IB shows substrate 100 having a further- processed backside surface 102B, wherein dielectric layer 112 and barrier layer 110 may have been removed from top surfaces 109 of TSVs 108 by a CMP process.
• the CMP process may continue to remove materials from and/or polish backside surface 102B of substrate 100 until backside surface 102C of FIG. 1C is produced, provided no TSV breakage occurs.
• TSVs 108 may be flush with surface 113 of dielectric layer 112 or, in some fabrication processes, slightly lower until a desired less-thick dielectric layer 112 is achieved.
• some copper dishing 111 may occur on the end surface of TSVs 108.
• a final soft buff may be provided to control surface finish and to remove small surface defects and imperfections. If no TSV breakage occurs, the final surface condition of substrate 100 may appear as shown in FIG. 1C upon completion of the TSV reveal process .
• FIG. 2 shows a micrograph of substrate 200 having a TSV 208 and a surrounding backside substrate surface 202 upon completion of a TSV reveal process without TSV
• FIG. 3 shows a substrate 300 having a processed backside surface 302 with TSV breakage in accordance with the prior art.
• TSV breakage may cause non-reworkable scratches and/or defects across a substrate surface that may adversely affect IC chip yield and reliability.
• Substrate 300 may have a silicon base layer 304, a metal (e.g., copper) layer 306, TSVs 308a and 308b, a barrier layer 310, and a dielectric layer 312.
• TSV 308b may have broken off during a CMP process. This breakage may have caused oxide gouging 315, which may expose silicon layer 304 to metal contamination during processing.
• TSV 308b may be formed with, e.g., copper, which is a relatively soft material. Copper smearing on silicon layer 304 caused by TSV breakage may potentially impact IC quality and/or reliability during post-packaging electrical testing.
• FIG. 4 shows a micrograph of a substrate 400 having a TSV 408 and a surrounding backside substrate surface 402 after TSV breakage. As shown, substantial surface scratching and defects may occur after breakage of TSV 408 during a CMP process. Furthermore, metal grains that may have been pulled out by the TSV breakage may cause, e.g., a metal pad 414 (i.e., the top surface of TSV 408) to not meet one or more specifications required for further processing, which may further impact IC yield and/or reliability .
• a metal pad 414 i.e., the top surface of TSV 408
• FIG. 5 shows a chemical mechanical polishing (CMP) system 500 in accordance with one or more embodiments.
• CMP system 500 may be configured to hold a substrate 501 in contact with a polishing pad 516 and may be used to perform a CMP process on substrate 501 as part of a TSV reveal process.
• Substrate 501 may be a silicon-containing wafer, such as a patterned wafer including partially or fully formed transistors and a plurality of TSVs formed therein.
• Substrate 501 may be affixed (e.g., via adhesives) to a second carrier wafer or other suitable backing such that a TSV reveal process may be performed on substrate 501.
• Polishing pad 516 may be mounted on a platen 518, which may be disk-shaped and rotated by a suitable motor (not shown) coupled to platen 518 by a shaft 520. Platen 518 may be rotated at between about 10-200 rpm. Other rotational speeds may be used.
• Substrate 501 may be held in a substrate holder 522. Substrate holders may also be referred to as retainers or carrier heads. In some embodiments, substrate 501 may be held to substrate holder 522 via a vacuum. Other suitable substrate holding techniques may be used. In some
• substrate holder 522 may be configured to move substrate 501 (i.e., up and down as shown) into contact with, and away from, polishing pad 516. Substrate holder 522 may be rotated and, and in some embodiments, oscillated back and forth across the surface of polishing pad 516 as polishing pad 516 is being rotated in contact with the backside surface of substrate 501. In some embodiments, the oscillation rate of substrate holder 522 may be between about 0.1 mm/sec and 5 mm/sec. Other oscillation rates may be used. In some embodiments, substrate holder 522 may be rotated at between about 10-200 rpm. Other rotational speeds may be used. The oscillation may take place between a center and a radial side of polishing pad 516. In some embodiments, substrate holder 522 may be a Contour, 5-zone pressure head available from Applied Material of Santa Clara, California.
• polishing pad 516/platen 518 and substrate 501/substrate holder 522 may be reversed. That is, polishing pad 516 and platen 518 may be part of or mounted to an overhead assembly or polishing head configured to move polishing pad 516 upward away from, and downward into contact with, the backside surface of substrate 501 held in substrate holder 522.
• Slurry 524 (a chemical polishing solution) may be applied to polishing pad 516 and inserted between polishing pad 516 and substrate 501 by a distributor 526.
• Distributor 526 may be coupled to a slurry supply 528 via one or more suitable conduits.
• a pump 530, a valve 532, or other liquid conveying and transfer mechanism may supply a metered amount of slurry 524 to the surface of polishing pad 516.
• slurry 524 may be dispensed by distributor 526 onto the surface of polishing pad 516 ahead of substrate 501 such that slurry 524 may be received in front of substrate 501 and may be drawn between polishing pad 516 and substrate 501 by the rotation of polishing pad 516.
• one or more parts of CMP system 500 may be equivalent to or based on those of, e.g., a Reflexion® GTTM CMP System, by Applied Material, of Santa Clara, California.
• CMP system 500 may also include one or more acoustic sensors 534a and/or 534b operable to sense acoustic emissions occurring during a CMP process performed on substrate 501.
• CMP system 500 may include only one of acoustic sensors 534a or 534b.
• CMP system 500 may include both acoustic sensors 534a and 534b.
• CMP system 500 may include more than two acoustic sensors, which may be positioned other than as shown for acoustic sensors 534a and 534b.
• Acoustic sensors 534a and/or 534b may be any suitable sensors 534a and/or 534b.
• acoustic sensor 534a may be physically coupled to platen 518 (or an overhead polishing head) in any suitable manner.
• acoustic sensor 534a may be mounted in a bracket that is mechanically fastened to platen 518.
• platen 518 may be an assembly that includes an upper platen and a lower platen (not shown) attached together.
• the upper platen may have a polishing pad 516 mounted thereon, wherein acoustic sensor 534a may be integrated or mounted below the upper platen or integrated or mounted to, e.g., an outside edge of the lower platen via, e.g., a bracket or other suitable mechanism.
• the bracket or other suitable mechanism may include a spring-loading mechanism to ensure that acoustic sensor 534a maintains constant contact with a polishing pad.
• the bracket or other suitable mechanism may include a cushioning pad to reduce signal attenuation or degradation.
• a power supply and signal cable (which may be represented at least partially by signal connection 536a) may, in some embodiments, be routed through platen 518 (or the lower platen of the platen assembly described above) and connected to sensor 534a via a high frequency (e.g., about 1 MHz) 8-terminal slip ring.
• acoustic sensor 534b in addition or alternative to acoustic sensor 534a, may be physically coupled to substrate holder 522 in any suitable manner.
• acoustic sensor 534b may be mounted in a bracket that is mechanically fastened to substrate holder 522.
• Acoustic sensors 534a and/or 534b may alternatively be located at other suitable positions relative to substrate 501 and polishing pad 516.
• acoustic sensors 534a and/or 534b may be built directly into, or integrated with, platen 516, substrate holder 522, and/or any other suitable component of CMP system 500 (see, e.g., platen 616 described below in connection with FIGs. 6A and 6B) .
• Acoustic sensors 534a and/or 534b may be
• acoustic processor 538 configured to detect TSV breakage based on acoustic
• Acoustic processor 538 may be part of system controller 540 as shown, or a separate, stand-alone
• System controller 540 may include a processor 542, which may control the operation of CMP system 500, including one or more CMP processes used in a TSV reveal process.
• system controller 540 may not be coupled to and/or may not include acoustic processor 538, but instead may have processor 542
• acoustic processor 538 additionally perform the functions of acoustic processor 538 described herein.
• Acoustic processor 538 may be configured to receive one or more signals representing acoustic emissions transmitted by acoustic sensors 534a and/or 534b. Acoustic processor 538 may be configured to detect TSV breakage by analyzing the one or more signals received from acoustic sensors 534a and/or 534b. The one or more signals received from acoustic sensors 534a and/or 534b may have amplitudes (representing, e.g., acoustic emission intensity) that may vary over time. Acoustic processor 538 may be configured to receive the time-varying signals and may compare the amplitudes thereof against one or more thresholds and/or threshold bands. Signal amplitudes exceeding those
• processing of received signals may involve comparing certain aspects or areas of received signal waveforms to preset thresholds.
• Acoustic processor 538 may include suitable signal filtering, amplifying, conversion (e.g., A/D conversion), and
• processing components may include suitable memory configured to store data and one or more analyses .
• the data and analyses may be stored, for example, in any suitable storage medium (e.g., RAM, ROM, or other memory) of acoustic processor 538 and/or system controller 540.
• the one or more stored analyses and data may be used to monitor and control one or more CMP processes relative to detection of TSV breakage .
• a frequency-based analysis may be used to process acoustical data.
• a high sampling rate acquisition of acoustical signals from acoustic sensors 534a and/or 534b may allow use of stationary signal analysis such as fast Fourier transformations (FFT) or non-stationary signal analysis such as wavelet packet transformations (WPT) .
• WPT may decompose a received acoustic signal into two parts, a low-frequency component that may yield
• the decomposition may be iterated with subsequent approximations being decomposed in turn.
• a time-based analysis may be used to process acoustical data. For example, a simple root mean square (rms) of received acoustical signals from acoustic sensors 534a and/or 534b may be monitored, provided TSV breakage events possess sufficiently large signal spikes in terms of signal-to-noise ratio.
• rms root mean square
• a first setup substrate with no protruding TSV stubs may undergo a CMP process to create baseline acoustical signal data for normalization.
• a second setup substrate with very high protruding TSV stubs e.g., 15 ]im stub lengths with 5 ⁇ diameters
• the second setup substrate may be inspected after processing for TSV breakage using, e.g., an optical
• Any signal spikes visible in the acoustic activity above the baseline signal during steady state CMP processing may be categorized as breakage signals, which may then be used to correlate TSV breakage events .
• Acoustic processor 538 may automatically respond to detection of TSV breakage by initiating one or more remedial actions .
• the remedial actions may include
• remedial actions may additionally or alternatively include
• the remedial actions may
• acoustic processor 538 may be configured to automatically reduce a down force applied by substrate holder 522 against polishing pad 516 (or vice versa) and/or automatically reduce a rotation speed of substrate holder 522, platen 518, or both in accordance with one or more programmed routines executed by acoustic processor 538 or system controller 540 in response to detecting TSV breakage. This may allow CMP system 500 to automatically continue processing subsequent substrates with the modified processing parameters.
• FIGs. 6A and 6B show an assembly 600 of a
• Platen 618 may include a disk- shaped base 644 configured to receive polishing pad 616 on a surface 617 of disk-shaped base 644.
• Disk-shaped base 644 may have one or more through-holes 633a, 633b, and 633c. That is, in some embodiments, disk-shaped base 644 may have only one of through-holes 633a, 633b, and 633c, or only two of through-holes 633a, 633b, and 633c, or more than the three through-holes 633a, 633b, and 633c.
• Platen 618 may also include one or more acoustic sensors 634a, 634b, and/or 634c received in respective through-holes 633a, 633b, and 633c.
• acoustic sensors 634a, 634b, and/or 634c may be friction fit in respective through-holes 633a, 633b, and 633c.
• acoustic sensors 634a, 634b, and/or 634c may be physically coupled to or integrally formed with disk-shaped base 644 in any suitable manner.
• platen 618 may have through-holes 633a, 633b, and 633c that do not have an acoustic sensor received therein.
• acoustic sensors 634a, 634b, and/or 634c may protrude from surface 617 of disk-shaped base 644 by a distance Dl .
• Distance Dl may be selected to reduce acoustical signal attenuation that may occur in, e.g., a polyurethane soft SUBATM portion of some embodiments of polishing pad 616.
• distance Dl may be about 50 mils (about 1.27 mm) . This may ensure that one or more of acoustic sensors 634a, 634b, and/or 634c may be in close proximity to polishing surface 621 of polishing pad 616, yet not likely to be damaged during polishing.
• acoustic sensor 634a may be located at about the center of platen 618. This center position may ensure that the distance of acoustic sensor 634a to a substrate being processed remains constant.
• Acoustic sensor 634b may be located radially outward from the center of platen 618 by about a distance D2, and acoustic sensor 634c may be located radially outward from the center of platen 618 by about a distance D3.
• distance D2 may be about 5 inches (about 12.7 cm) radially outward from the center of platen 618
• distance D3 may be about 10 inches (about 25.4 cm) radially outward from the center of platen 618.
• the D3 distance of about 10 inches (about 25.4 cm) may ensure that acoustic sensor 634c is positioned nearest the substrate on every rotating pass.
• received acoustic data may be filtered out.
• Distances D2 and/or D3 may alternatively have other suitable dimensions .
• Acoustic sensors 634a, 634b, and/or 634c may each be configured to be electrically coupled to a controller or acoustic processor via a wired or wireless connection.
• acoustic sensors 634a, 634b, and/or 634c may include electrical connectors 646a, 646b, and/or 646c, respectively, accessible below platen 618 (i.e., opposite surface 617) .
• polishing pad 616 may be mounted to disk-shaped base 644 and may have one or more non-through holes 635a, 635b, and 635c on a base-side surface 619 of polishing pad 616.
• Non-through holes 635a, 635b, and 635c may have a depth of about distance Dl and may be configured to receive therein the protruding portion of one or more of respective acoustic sensors 634a, 634b, and/or 634c.
• the number and positions of non-through holes 635a, 635b, and 635c may correspond respectively to the number and positions of through-holes 633a, 633b, and 633c of platen 618.
• Polishing pad 616 may be identical or similar to, e.g., an IC1000TM polishing pad with SUBATM IV subpad having one or more non-through holes 635a, 635b, and/or 635c formed therein.
• any one or more of acoustic sensors 534a, 534b, 634a, 634b, and/or 634c may be a piezoelectric, a transducer, and/or an accelerometer type sensor, and each may have a high signal to noise ratio.
• Acoustic sensors 534a, 534b, 634a, 634b, and/or 634c may include, in some embodiments, a flat frequency response over a region of about 100-500 kHz. In some embodiments, any one or more of acoustic sensors 534a, 534b, 634a, 634b, and/or 634c may amplify an acoustic signal with a gain of about 40- 60 dB . Acoustic sensors 534a, 534b, 634a, 634b, and/or 634c may include, in some embodiments, a high pass filter having a range of about 50Hz-100Hz. Any suitable acoustic sensor may be used for sensors 534a, 534b, 634a, 634b, and/or 634c.
• FIG. 7 illustrates a method 700 of monitoring and controlling a TSV reveal process in accordance with one or more embodiments.
• method 700 may include processing a substrate using a CMP process.
• the CMP process may be part of a TSV reveal process.
• substrate 100 having backside surface 102A may be received at CMP system 500.
• Substrate 100 may be mounted or attached to substrate holder 522 and pressed against polishing pad 516 for CMP processing as shown and described in connection backside surfaces 102B and 102C or possibly 302.
• sensing acoustic emissions of the CMP process may occur.
• sensing acoustic emissions may be performed by any one or more of acoustic sensors 534a, 534b, 634a, 634b, and/or 634c.
• the acoustic emissions may be from a CMP process in which a substrate, such a, e.g., substrate 100 having backside surface 102A of FIG. 1A or substrate 501 of FIG. 5, is being processed with a polishing pad, such as polishing pad 516 of FIG. 5 or polishing pad 616 of FIGs. 6A and 6B.
• Acoustic sensors 534a, 534b, 634a, 634b, and/or 634c may sense the acoustic emissions resulting from the processing of substrate 100 or 501 and may transmit electrical signals representing those acoustic emissions to a controller and/or acoustic processor, such as, e.g., system controller 540 and/or acoustic processor 538.
• a controller and/or acoustic processor such as, e.g., system controller 540 and/or acoustic processor 538.
• method 700 may include analyzing the acoustic emissions to detect TSV breakage. Analysis of the acoustic emissions may include comparing one or more parameters (e.g., amplitude) of one or more received signals to one or more thresholds and/or threshold ranges.
• the one or more received signals may represent acoustic emissions from a CMP process, and the one or more thresholds and/or threshold ranges may indicate whether or not TSV breakage has occurred during the CMP process.
• the one or more thresholds and/or threshold ranges may have been predetermined during one or more baseline CMP processes performed on first and second setup substrates where TSV breakage has and has not occurred, respectively.
• method 700 may proceed to process block 710.
• a high spike in a received acoustical signal may trigger method 700 to proceed to process block 710 in accordance with a pre-defined algorithm that may be part of a program executing on, e.g., acoustic processor 538, or part of endpoint software executing on, e.g., system controller 540. If TSV breakage is not detected, method 700 may proceed to decision block 712.
• method 700 may include automatically responding to the detection of TSV breakage. In some embodiments, this may include automatically
• method 700 may respond to detection of TSV breakage by additionally or alternatively automatically modifying the CMP process by, e.g., reducing a down force, reducing a rotation speed, or both.
• Method 700 may additionally or alternatively respond to detection of TSV breakage by automatically stopping the CMP process. This may occur by proceeding directly to terminal block 714 (path shown in dashed line) or, in some embodiments, by proceeding to decision block 712 wherein a YES response may automatically be triggered, thus
• Method 700 may otherwise proceed to decision block 712.
• method 700 may include determining whether an endpoint of a CMP process has been detected.
• Endpoint detection may be performed by a system controller of a CMP system, such as, e.g., system controller 540 of CMP system 500.
• endpoint detection for a TSV reveal process may include detecting the point at which TSVs are planarized flush to a dielectric oxide surface, such as shown in FIGs. 1C and 2.
• This endpoint detection may be determined by, e.g., acoustical analysis and/or motor torque feedback of a motor driving, e.g., the rotation of a polishing pad. Both acoustical analysis and motor torque feedback may be based on
• a frictional change may occur between the substrate surface and a polishing pad that may be indicated in one or more received acoustical signals and/or in received motor torque feedback.
• endpoint detection for a TSV reveal process may be determined based on a white light spectrograph indicating a specific oxide thickness. If an endpoint has been detected at decision block 712, method 700 may proceed to termination block 714. Otherwise, method 700 may return to process block 704.
• method 700 and the processing of a substrate using a CMP process may end.
• process block 704 may be performed simultaneously with process blocks 706 and/or 710 and/or with decision blocks 708 and/or 712.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Manufacturing & Machinery (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=51841646

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (17)

Citations (5)

Family Cites Families (28)

• 2013
  • 2013-05-01 US US13/874,495 patent/US20140329439A1/en not_active Abandoned
• 2014
  • 2014-04-28 TW TW103115201A patent/TWI686264B/zh active
  • 2014-04-28 JP JP2016511785A patent/JP6397896B2/ja active Active
  • 2014-04-28 WO PCT/US2014/035756 patent/WO2014179241A1/en not_active Ceased
  • 2014-04-28 KR KR1020157034275A patent/KR102242321B1/ko active Active
  • 2014-04-28 CN CN201480024607.1A patent/CN105164794B/zh active Active

Patent Citations (5)

Also Published As

Similar Documents

Legal Events