中科微点-全球专利检索

  1. Login
  2. Sign Up

Search Results

15 records (took 0.017 seconds)

    11.
    发明专利
    未知

    公开(公告)号：DE2525235A1

    公开(公告)日：1976-01-15

    申请号：DE2525235

    申请日：1975-06-06

    Applicant: IBM

    Inventor： DAVIS DONALD E ,  HABEGGER MILLARD A ,  MOORE RICHARD D ,  WEBER EDWARD V ,  WOODARD OLLIC C

    IPC: G05D3/12 ,  H01J37/304 ,  H01L21/027 ,  H01J3/10

    Abstract: 1508903 Wave energy position finding INTERNATIONAL BUSINESS MACHINES CORP 23 May 1975 [27 June 1974] 22919/75 Heading G1A [Also in Division H4] The position of a registration mark on a target (e.g. a semi-conductor wafer) is detected by irradiating the mark with a beam of charged particles. The present invention is stated to be an improvement over the system described in Specification 1480562. As described, each mark 42, Fig. 17, consists of vertical and horizontal bars 44, 43 (raised portions or depressions), the position of the mark being determined from 20 horizontal (X) scans followed by 20 vertical (Y) scans, successive scans being in opposite directions. Peak signals corresponding to the edges of a bar are detected and applied to threshold circuitry which is updated during each scan. Diodes 45, 46 and 45', 46' detect radiation during X, Y scans respectively, the arrangement including extra diodes 47 and an extra lead going to a respective preamplifier 48-66 for noise suppression. X-scanning: The outputs 70, 71 from diodes 45, 46 contain peaks 72 &c. corresponding to the edges of a bar 44. These signals pass to a differential amplifier 69 via balancers 58, 60 which compensate for the fact that the mark being scanned will be nearer one diode than the other. The output 85, Fig. 13, from amplifier 69 contains positive and negative peaks 86, 87 corresponding to the edges of a bar. The signals are shown without any ramp component. Such component is removed in filter 89 to leave the peak signals plus a substantially constant residual baseline voltage, Figs. 14 and 15 (not shown). The output from filter 89 is fed via an AGC circuit 90 to positive and negative peak detectors 99, 100 and an averaging circuit 122. During the first scan, outputs 103, 104 from detectors 99, 100 are used to set the gain levels in AGC 90 for subsequent scans so as to compensate for the surface conditions on the wafer in the region of the mark being scanned. At the end of the first scan the contents of 99, 100, 122 are passed to stores 143, 128, 136 the outputs of which are combined by means of resistors 144, 140, 137 to produce positive and negative threshold signals 134 and 141 which are correlated with the residual baseline voltage. These signals pass via differential amplifiers 135, 142 to act as threshold levels for voltage comparators 118, 119 receiving signals from AGC 90 via a switch 116 (blocked during the first scan). During the second scan, fresh data is fed to detectors 99 &c. and stores 143 &c. and switch 116 is enabled to pass the output of AGC 90 to the comparators, outputs of which are however not used until the third scan. During the third and subsequent scans, comparators 118, 119 produce signals whenever the signals from AGC 90 cross the levels set during the preceding scan by amplifiers 135, 142. The ORed outputs from 118, 119 enable a gate 151, so that clockpulses 153 pass to a feedback channel 152 and a computer 19 which uses the detected-edge signals, averaged over the last 18 scans, to determine the location of mark 42. Since successive scans occur in opposite directions, stores 143, 136 incorporate means for reversing the sign of their outputs, so that detectors 99, 100 continue to detect the same edge of a bar 44 during successive scans. The Y-scan is then performed in the same way. The various blocks of Fig. 2 are described in detail with reference to Figs. 3-9 (not shown).

    METHOD AND APPARATUS FOR CONTROLLING AN ELECTRON BEAM
    12.
    发明专利
    METHOD AND APPARATUS FOR CONTROLLING AN ELECTRON BEAM 未知

    公开(公告)号：CA942429A

    公开(公告)日：1974-02-19

    申请号：CA99714

    申请日：1970-12-03

    Applicant: IBM

    Inventor： KRUPPA ROBERT W ,  WEBER EDWARD V ,  WOODARD OLLIE C

    IPC: H01J37/30 ,  G05B19/39 ,  H01J37/304 ,  H01L21/00 ,  H01L21/027

    Abstract: 1329559 Programmed control INTERNATIONAL BUSINESS MACHINES CORP 3 Dec 1970 [15 Dec 1969] 57380/70 Heading G3N [Also in Division H1] A beam of charged particles, scanning in a raster over a workpiece, is precisely positioned by determining beam error with respect to a reference position, storing the error and correcting the raster position accordingly. As shown, an electron beam from a gun 10 is directed through a square aperture 12, which shapes it to a beam 11 of a size equal to the minimum line width of a raster pattern to be formed on a workpiece mounted on a table 29. The beam is electro-magnetically focussed by a coil 15 and passes between blanking plates 16. The beam 11 is then passed through a circular aperture 19, which passes only axial charged particles, so that a square shaped spot without distortion is produced. The beam is subjected to co-ordinate deflections by electromagnetic coils 21-24 and electro-static plates 25-28. The table 29 is moved in co-ordinate directions by motors 30, 31, 31'. To ascertain the correct focus and astigmatism of the beam 11 a grid 47 of copper foil is mounted on the table and the focus detected by a PIN diode, not shown, the output of which through an interface circuit 17 is interrogated by a computer 18 which provides signals to the circuit 17 for control of the electron beam. The calibration of the beam 11 is ascertained by use of a grid 60 of copper foil having a pattern with accurately dimensioned square openings. The beam is detected by a PIN diode, not shown, and the error is determined by and stored within the computer for subsequent use during the execution of a programmed electron beam machining operation on chips on a semi-conductor substrate positioned by co-ordinate movement of the table. The beam is moved across the substrate in a raster pattern by signals from the interface circuit to coils 21-24 under control of the computer and correction signals applied to plates 25-28. The beam is held stationary in a position determined by the programme by the application of a bucking sawtooth waveform to the X electrostatic plates 25, 26. It is stated that the electrostatic plates 25-26 could be replaced by high frequency electromagnetic coils and the focus grid 47 omitted and the calibration grid 60 utilized for focusing. Facilities are provided whereby, on substitution of a substrate, the table can be rotated by a motor, not shown, to the align the substrate with the scanning directions.

    METHOD AND APPARATUS FOR CONTROLLING BRIGHTNESS AND ALIGNMENT OF A BEAM OF CHARGED PARTICLES
    14.
    发明专利
    METHOD AND APPARATUS FOR CONTROLLING BRIGHTNESS AND ALIGNMENT OF A BEAM OF CHARGED PARTICLES 未知

    公开(公告)号：CA1041178A

    公开(公告)日：1978-10-24

    申请号：CA231509

    申请日：1975-07-15

    Applicant: IBM

    Inventor： HALL ALAN V ,  PERKINS MERLYN H ,  PFEIFFER HANS C ,  WEBER EDWARD V ,  WOODARD OLLIE C

    IPC: H01J37/305 ,  H01J37/147 ,  H01J37/304 ,  H01L21/027 ,  H01J37/31

    Abstract: METHOD AND APPARATUS FOR CONTROLLING BRIGHTNESS AND ALIGNMENT OF A BEAM OF CHARGED PARTICLES A beam of charged particles has its alignment and brightness alternately controlled in accordance with the current of the beam. The measurements of the current and any corrections for alignment or brightness are made when the beam is not applied to a target. In operation the beam is applied to the target for a predetermined period of time. When the beam is not applied to the target it's positioning on the target is aligned and the brightness of the beam is controlled. This aligning and controlling occurs during a predetermined period of time between the periods of time when the beam is actually applied to the target. Apparatus for maintaining the substantially uniform current density of the beam of charge particles is also provided.

Patent Agency Ranking