Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/073—Multiple probes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
  • G01R31/2851—Testing of integrated circuits [IC]
  • G01R31/2886—Features relating to contacting the IC under test, e.g. probe heads; chucks
  • G01R31/2887—Features relating to contacting the IC under test, e.g. probe heads; chucks involving moving the probe head or the IC under test; docking stations
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
  • G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
  • G01R31/2831—Testing of materials or semi-finished products, e.g. semiconductor wafers or substrates

Definitions

• This application relates to alignment apparatuses for use in testing, drilling, and trimming of printed circuit boards and integrated circuit substrates and, in particular, to an improved alignment apparatus that isolates a rotational positioning mechanism ( ⁇ stage) of the apparatus from the effects of a translating workpiece positioning mechanism (X-Y stage), and vice versa.
• the manufacture of electronic circuits such as printed circuit boards and integrated circuits typically involves inspection and testing of each circuit in an array of circuit patterns formed on a substrate.
• Calibration of circuits may include probing and measurement of electrical characteristics of circuit components during a laser trimming operation that adjusts the electrical characteristics of the circuit.
• the tips of test probes of a probe card must be accurately aligned with contact locations or electrode pads of the circuit.
• Probe alignment systems use mechanical positioning equipment that adjusts the position of the substrate, the probe card, or both, to maintain accurate alignment across the array of circuit patterns.
• FIG. 1 illustrates a prior-art test probing system 10, in which a substrate 12 is supported on a chuck 16 of a motorized workpiece positioning stage 20.
• Positioning stage 20 includes a linear positioning component, X-Y stage 22, supported on a platen 24, for movement in a horizontal plane in orthogonal directions X and Y.
• Positioning stage also includes a rotational positioning component, theta ( ⁇ ) stage 26, supported on the X-Y stage 22 for rotation of the chuck 16 about a vertical Z axis.
• a Cartesian coordinate system frame of reference 30 indicates the directions X, Z, and ⁇ (the Y direction is perpendicular to the view and is not shown in FIG. 1 ).
• a probe card carriage 34 holds a probe card 38 above the positioning stage 20 while a machine vision system 42, including a camera 44, controls the rotational ( ⁇ ) and translational (X-Y) alignment of the substrate 12 to align it with probes 48 of the probe card 38.
• the probe card carriage 34 is supported below a motorized Z stage 50 that is actuated, after alignment of the probe card 38, to move the probe card 38 downwardly along the Z axis to press the probes 48 against the substrate 2 for testing of a circuit formed on the substrate 12.
• a Z-drive mechanism 56 which is supported on a stationary probe base 60, provides driving force for Z stage 50.
• a second rotational positioning stage is provided for aligning the probe card with the X and Y axes of the X-Y stage, thereby enabling probe/substrate alignment to be more accurately maintained across the entire array of circuit patterns of the substrate.
• these prior art mechanisms all include a ⁇ stage tied to the X-Y stage, every adjustment of the ⁇ stage requires a subsequent alignment compensation of the X-Y stage, as explained by Spano et al. at column 4, lines 16-24 of the '191 patent.
• the mass of the ⁇ stage adds to the inertia of the entire workpiece positioning stage.
• the added inertia slows movement in the X and Y directions and raises the center of mass of the workpiece positioning stage, thereby affecting positioning speed and accuracy.
• the ⁇ stage can also be a source of positioning error due to vibration and backlash that are induced in the ⁇ stage mechanism each time the X-Y stage is actuated.
• the coupling of the ⁇ stage with the workpiece positioning stage in conventional test probe alignment systems tends to reduce system throughput.
• Attempts to increase X-Y stage speed by minimizing the mass of the ⁇ stage and reducing the height and/or mass of the chuck tend to increase backlash, decrease stiffness, sacrifice vibration resistance, and increase settling time of the workpiece positioning stage.
• Attempts to increase the resolution and accuracy of the ⁇ stage also tend to increase the mass and height of the workpiece positioning stage. Consequently, designers of prior art systems have been forced to compromise system throughput to improve positioning accuracy, and vice versa.
• the present inventor has recognized a need for an improved test probe alignment apparatus that will facilitate increased test throughput and improved probe alignment accuracy.
• An alignment apparatus is adapted for aligning a set of test probes or other tools with a set of contact areas on a substrate, such as a printed circuit board panel or finished silicon wafer.
• the substrate is supported on a chuck of a workpiece positioning stage for linear movement in an X-Y plane.
• the alignment apparatus also facilitates engagement of the test probes with the contact areas on the substrate after alignment, by driving the test probes in a Z direction.
• the alignment apparatus includes a rotatable stage that is decoupled from the workpiece positioning stage so that the chuck can move in the X-Y plane without moving the rotatable stage, thereby inhibiting vibration in and inertia of the workpiece positioning stage, and improving the speed and accuracy of chuck movements.
• the rotatable stage is driven for rotation about an axis of rotation substantially perpendicular to the plane of movement of the chuck.
• the rotatable stage preferably supports a carriage adapted for mounting a set of probes.
• the carriage rotates in concert with the rotatable stage when the rotatable stage is rotated, to thereby align the set of probes with the contact areas on the substrate.
• the probing stage is driven for linear translation of the carriage relative to the rotatable stage along the axis of rotation of the rotatable stage to thereby engage the probes with the contact areas on the substrate.
• the rotatable stage is decoupled from the workpiece positioning stage, it is less constrained by space and mass limitations than prior art systems. Thus, it can include larger, more massive mechanisms that are more accurate than the ⁇ stages used with workpiece positioning stages of prior-art test systems.
• FIG. 1 is a schematic front elevation of a prior-art test probing system
• FIG. 2 is a schematic front elevation of a test probing system including a test probe alignment apparatus in accordance with simplified first embodiment
• FIG. 3 is a top perspective view showing a test probe alignment apparatus in accordance with a second embodiment, with Z-drive belts of the alignment apparatus omitted for clarity;
• FIG. 4 is a bottom perspective view of the test probe alignment apparatus of FIG. 3;
• FIG. 5 is a top right frontal perspective view of a third embodiment test probe alignment apparatus, with a probe card holder of the probe alignment apparatus omitted;
• FIG. 6 is a top left perspective view of the test probe alignment apparatus of FIG. 5;
• FIG. 7 is a top plan view of the test probe alignment apparatus of FIG. 5;
• FIG. 8 is a right side elevation of the test probe alignment apparatus of FIG. 5;
• FIG. 9 is a front side elevation of the test probe alignment apparatus of FIG. 5; [0023] FIG. 10 is an exploded view of the test probe alignment apparatus of
• FIG. 5 with a left front Z-screw of the alignment apparatus omitted to show detail of a ⁇ stage pedestal of the alignment apparatus;
• FIG. 11 is an enlarged partial top plan view of the test probe alignment apparatus of FIG. 5, showing detail of a ⁇ stage driver mechanism.
• FIG. 2 is a schematic front elevation of a test probing system 100 including a test probe alignment apparatus 108 in accordance with simplified first preferred embodiment.
• test probing system 100 includes a workpiece positioning stage 110 consisting essentially of an X-Y stage 114 that supports a chuck 116 having an upper surface 118.
• the X-Y stage 114 moves over a stationary horizontal platen 124 in orthogonal X and Y directions lying in a substantially horizontal plane (the X direction is indicated by arrow 126 and Cartesian coordinate reference frame 128; the Y direction extends perpendicular to the drawing and is, therefore, not depicted on reference frame 128) in response to • actuation of an X-Y forcer mechanism 130 of X-Y stage 114.
• X-Y stage 114 may be in a stacked configuration, having the X-stage supported on the Y-stage or vice versa; however, X-Y stage preferably includes an X-Y dual axis single plane stepping motor with air bearing.
• X-Y table 114 may include non-orthogonal forcers, so long as they do not cause chuck 116 to rotate.
• Platen 124 may be securely mounted to a frame 132 of test probing system 100, for example.
• Upper surface 118 of chuck 116 is sized to fit a substrate 134 on which one or more circuits are formed. Preferred embodiments are used in connection with testing and/or trimming of circuits on substrates such as printed circuit boards (PCBs), including PCB panels carrying an array of printed circuit boards (not shown).
• PCBs printed circuit boards
• chuck 116 could be sized up to 26 inches wide and 30 inches long, for example, and weigh up to 17 pounds (mass 7.7 kg).
• Embodiments are also contemplated to be scaled down for use in testing smaller substrates, such as miniaturized integrated circuits and wafers having an array of integrated circuit dice formed thereon, in which case chuck 116 and X-Y stage 114 would be sized much smaller than for PCB testing.
• a probe stage 140 includes a stationary base plate 144, which may be securely mounted to frame 132 of test probing system 100 or to another rigid stationary support.
• a ⁇ stage 148 is mounted on base plate 144 and includes a pedestal 150 that driven by a ⁇ drive mechanism 154 of ⁇ stage 148 for rotation about an axis of rotation 156 perpendicular to the X-Y plane in which chuck 116 moves.
• a translating Z stage 160 is supported by pedestal 150 and moves with pedestal 150 in response to actuation of ⁇ drive mechanism 154.
• a carriage 164 is hung from Z stage 160 below pedestal 150 and adapted for mounting a probe card 166 having a set of test probes 167. Probe card 166 is mounted such that probes 167 face chuck 116.
• Carriage 164 rotates in concert with Z stage 160 when ⁇ stage 148 is rotated, to thereby align the set of probes 167 with contact areas (not shown) on substrate 134.
• Z stage 160 preferably extends beyond an upper face 168 of pedestal 150 where Z stage 160 is coupled to a Z-drive mechanism 172 that drives Z stage 160 and carriage 164 for linear translation along Z-axis relative to ⁇ stage 148.
• Driving of Z stage 160 and carriage 164 along the Z-axis causes the tips of test probes 167 to press against the contact areas of substrate 134 for purposes of electrical testing, laser trimming, or any other process involving probing.
• Z stage 160 and/or Z-drive mechanism 172 may be arranged so that Z stage 160 or Z-drive mechanism 172 or both do not rotate together with ⁇ stage 148 and carriage 164. Decoupling of Z stage 160 or Z-drive mechanism from ⁇ stage 148 would require a special rotating- or slide bearing- type coupling to allow carriage 164 to rotate independently of the
• Motion controller 186 includes control software stored in a computer-readable data storage medium, such as computer memory (not shown) of motion controller 186 or a remote data storage device that can be accessed by motion controller 186.
• a computer-readable data storage medium accessible by motion controller 186 is also adapted to store movement vector data representing preprogrammed movements of X-Y stage 114, ⁇ stage 148, and/or Z stage 160.
• a step-and-repeat indexing plan is stored in the data storage medium for positioning substrate 134 to test multiple sets of circuits or dice on substrate 134.
• motion controller 186 uses position information sensed by sensor 180 to adjust the alignment of ⁇ stage 148 and X-Y stage 114 before or during execution of the preprogrammed movements.
• FIGS. 3 and 4 respective top and bottom perspective views show a test probe alignment apparatus 200 in accordance with a second preferred embodiment.
• FIG. 3 omits an X-Y stage and detail of probe cards and probes, which are components well known in the art. The manner of using the X-Y stage and probe cards in conjunction with test probe alignment apparatus 200 will be readily appreciated and understood by anyone of skill in the art.
• Alignment apparatus 200 includes a stationary base plate 204 that is mounted to a frame (not shown) above the X-Y stage (not shown).
• a ⁇ stage 210 includes a ring bearing 214 having a pair of opposing bearing races (not shown), including a first (fixed) bearing race securely attached to base plate 204.
• a pedestal 218 is mounted to a second
• a ⁇ drive mechanism 230 includes a ⁇ drive servo 232 that actuates a linear slide 234 of a taut-band mechanism 236, which is connected to pedestal 218.
• Taut-band mechanism 236 provides highly reliable and precise control for rotation of ⁇ stage 210, while eliminating backlash. Actuation of linear slide 234 causes ⁇ stage
• Test probe alignment apparatus also includes a Z stage 250, comprising a
• Z-stepper motor 254 coupled to Z-pulleys 258 of each of four Z-screws 260a, 260b,
• Non-rotating lead screws 264 of Z-screws 260a-d are threaded into and extend downwardly from Z- pulleys 258 through pedestal 218 so that they telescope in the Z direction in response to actuation of Z-stepper motor 254.
• a carriage 270 is rigidly attached to the ends of lead screws 264 for movement therewith.
• a probe card holder 274 is attached to carriage 270 and includes a pair of opposing card slot rails 278a and
• ⁇ stage 210 and Z stage 250 are also contemplated to be within the scope of the present application.
• a Z-stage could directly connect to pedestal 218 and a lightweight ⁇ stage could be mounted to a working end of the Z-stage.
• FIGS. 5 and 6 are respective top/right frontal perspective and top left perspective views of a third embodiment test probe alignment apparatus 300, with a probe card holder of the probe alignment apparatus omitted for clarity.
• FIG. 7 is a top plan view of test probe alignment apparatus 300.
• FIGS. 8 and 9 are respective right side and front side elevations of test probe alignment apparatus 300.
• FIG. 10 is an exploded view of test probe alignment apparatus 300, with a left front Z-screw
• FIGS. 5-10 many elements are shown with reference numbers that have the same last two digits and the reference numbers shown in of FIGS. 3 and 4 for corresponding components. These elements are listed below by name for reference.
• a set of four Z-drive belts 380 engages Z-pulleys 358 and Z-stepper motor 354 to drive Z-screws 360a-d in response to actuation of Z-stepper motor 254.
• Z-drive belts 380 are preferably endless timing belts, but could be implemented with other types of linkage devices.
• Multiple tensioner idlers 384 are provided for maintaining tension of Z-drive belts 380.
• Z-screws 360a-d are preferably ball screws.
• a set of dust covers 386 is provided to protect the screw portions (not shown) of Z-screws 360a-d.
• a pair adjustable anti- backlash springs 388 is provided for biasing carriage 370 along the Z-axis to eliminate axial play in the ball screws.
• Springs 388 are connected at one end to carriage 370 and their other end to a pair of spring posts 390 mounted on pedestal 318. Springs 388 are preferably in tension to urge carriage 370 toward pedestal
• Spring posts 390 facilitate installation and adjustment of a spring preload of springs 388.
• FIG. 11 is an enlarged partial top plan view of the test probe alignment apparatus 300, showing detail of ⁇ drive mechanism 330.
• taut-band mechanism 336 includes a crossed pair of flexible bands 410 and 412, which are highly inelastic along their lengths. Each of the bands 410 and 412 extend between and are attached at one end to linear slide 334, and at their other end to respective adjustment clamps 418 and 420 (see also FIG. 9). Throughout the range of travel of ⁇ drive mechanism 330, the bands 410 and 412 remain in contact with a curved face of a taut block 430, to which adjustment clamps 418 and 420 are mounted.
• a home switch 440 is provided for re-zeroing taut-band mechanism 336
• the test probe alignment apparatus may include a memory adapted to store an indexing plan corresponding to the circuit array pattern.
• the indexing plan includes a set of movement vectors defining spatial offsets between pairs of circuits in the array pattern and may be preprogrammed in memory for a known array pattern or "taught" or otherwise input to the system when needed.
• a position sensor such as a machine vision system and camera 182 (FIG. 2), is provided for measuring angular misalignment of the array pattern relative to orthogonal axes of the chuck within the plane of movement of the chuck.
• Fiducial marks on the substrate which are typically formed in the same lithography process as the array pattern, facilitate accurate optical measurement by the position sensor.
• the position sensor may also measure the translational misalignment of the array pattern relative to the orthogonal axes.
• motion controller 186 in communication with the memory and the sensor, performs a coordinate transformation on the movement vectors based on the angular misalignment measured by the system.
• Probe alignment apparatuses in accordance with the various embodiments described herein eliminate the need to twice perform the steps of measuring the misalignment and adjusting the position of the substrate (once for angular position adjustment and once for adjusting in the translational position).
• the invention obviates the two stage alignment process of the prior art by using the angular and/or positional offset of the substrate measured by the sensor to compensate in software (with coordinate transformations) for misalignment between the array pattern and the axes of movement of the chuck.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• General Engineering & Computer Science (AREA)
• Testing Or Measuring Of Semiconductors Or The Like (AREA)
• Measuring Leads Or Probes (AREA)
• Tests Of Electronic Circuits (AREA)

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Citations (5)

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• 2003
  • 2003-03-21 US US10/393,955 patent/US7119566B2/en not_active Expired - Lifetime
  • 2003-03-21 GB GB0416819A patent/GB2400447B/en not_active Expired - Fee Related
  • 2003-03-21 JP JP2003580875A patent/JP4803959B2/ja not_active Expired - Fee Related
  • 2003-03-21 DE DE10392404T patent/DE10392404T5/de not_active Withdrawn
  • 2003-03-21 WO PCT/US2003/008913 patent/WO2003083494A1/en not_active Ceased
  • 2003-03-21 TW TW092106285A patent/TWI272392B/zh active
  • 2003-03-21 CN CNB038047314A patent/CN100430735C/zh not_active Expired - Fee Related
  • 2003-03-21 CA CA002476389A patent/CA2476389A1/en not_active Abandoned
  • 2003-03-21 AU AU2003218348A patent/AU2003218348A1/en not_active Abandoned
  • 2003-03-21 KR KR1020047014885A patent/KR101163972B1/ko not_active Expired - Lifetime

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