JP2014109449A - Probing tip for signal acquisition probe - Google Patents

Abstract

Broadening the bandwidth of a probing tip for a signal acquisition probe.
A curved probing tip contact having first and second arched surfaces and intersecting each other is formed at a convergence point of a non-conductive substrate included in the probing tip. A conductive material is laminated on the contact 24 by using a thin film method or a thick film method to form an electrical contact to the device under test. Resistive element 30 is formed on non-conductive substrate 12 using a thin film method. Resistive element 30 is electrically coupled to the input terminal of the amplifying circuit on integrated circuit die 36 mounted on non-conductive substrate 12 and to contact 24. The output terminal of the amplifier circuit is coupled to a transmission structure 70 formed on the second non-conductive substrate 58.
[Selection] Figure 3

Description

  The present invention relates to signal acquisition probes for measuring devices, and more particularly to probing tips formed on non-conductive substrates.

  A signal acquisition probe is used in connection with a measurement device such as an oscilloscope, a logic analyzer, a spectrum analyzer, etc., acquires a test signal from a device under test (DUT) into the measurement device, and analyzes and displays the test signal. Used for. The signal acquisition probe has at least one conductive probing tip, which is formed from a conductive material such as copper, beryllium copper, aluminum, iron, metal alloys such as nickel-palladium alloys. The shape of the probing tip is formed, for example, as a conical claw or pin that narrows toward one point. Other probing tip shapes may include tilt and wedge shapes.

  The signal acquisition probe includes a probe head having an electrically conductive hollow tube, and a substrate is disposed in the hollow tube. This substrate may be formed of ceramic or circuit board material, etc., and a passive or active circuit for preventing an increase in load on the test signal supplied to the measuring apparatus or adjusting the test signal is provided on the substrate. Provided on top. An insulating plug is provided at one end of the hollow tube, and a probing tip extends in both directions along the coaxial direction from the insulating plug. The portion of the probing tip that extends into the hollow tube is electrically connected to the substrate. The probing tip may be bonded to the substrate using spring-loaded electrical contacts, conductive fuzz buttons, wire bonding, soldering, and the like. A conductive cable is attached to the substrate to couple the conditioned electrical signal to the measuring device. The total bandwidth of a measurement probe using a metal probing tip is limited by the influence of the capacitance and inductance of the metal probing tip.

  With the increase in measurement bandwidth, there is a need for measurement probes having a bandwidth that is the same or wider than that bandwidth. The main reason that it is difficult to design a very wide bandwidth measurement probe with a bandwidth of 5 GHz or more is the effect of the capacitance (capacitance) and inductance of the probing chip (s). One way to solve this problem is to separate the probing tip from the active circuitry in the probing head of the measurement probe. US Pat. No. 6,704,670 (no corresponding Japanese application) discloses a broadband active probing system that allows the probe probing tip (s) to be separable from the probe amplification unit. ing. The probe tip unit is connected to the probe amplification unit via one or more probe cables, and the signal received by the probe tip unit is transmitted. Various types of probe tip units may be connected to the probe amplification unit. The probe tip unit may include a wide variety of electronic circuits from conductive wiring to various resistors, capacitors and other electronic elements. The advantage of such a probe design is that instead of a large measurement probe containing a probe amplifier circuit, a substantially smaller probe tip unit can be placed where it is difficult to reach the contacts.

  The probe tip unit may be single-ended or differential, and in this case includes a differential browser (signal reading unit) that can be held by hand (handheld) and adjustable in spacing. With this handheld browser, the user can manually move to various points on the device under test for testing. The probe tip unit may also have probe connection points for electrically connecting various types of probing tips to the probe tip unit. The probing tip is held at the probe connection point of the probe tip unit by soldering or compression terminal connection. Various types of probing tips, such as resistors, SMT grabbers (surface mount signal acquisition devices), wedge-shaped probe tips, etc. may be soldered to the probe connection points.

  US Pat. No. 7,056,134 (corresponding Japanese Patent No. 4,575,838) describes a detachable probing tip system that can be mounted on a probing tip member attached to a probe body via a coaxial cable. Yes. This detachable probing tip system has a probe tip mounting member, which is a wire lead extending from a resistive element, or conductive wiring placed on an elastic circuit member formed as a probing arm Receive various types of probing tips, such as resistors with wire leads attached to The probe tip mounting member has a mounting arm that engages the probe tip member, and the probing tip is held and electrically connected to the probe tip member.

  In the probing tip system described above, a braking resistor can be placed in close proximity to the probe contact point on the device under test using the wire lead of this resistor. By placing a resistive element near the probe contact point on the device under test, the high frequency loading of the device under test is reduced and the effect of the capacitance of the resistor metal leads is reduced. The A probe bandwidth as high as 20 GHz is realized by using the above-described probing system.

US Pat. No. 6,704,670 US Pat. No. 7,056,134

  There continues to be a need for signal acquisition probes with higher bandwidth. To do so, it is necessary to reconsider how the signal acquisition probe makes electrical contact with the test points on the device under test. Replacing traditional metal probing tips, which are traditionally metal tips, and traditional metal wire leads for resistors, is one way to increase the bandwidth of signal acquisition probes to the 30 GHz range. It is a draft.

  The present invention is a probing tip for a signal acquisition probe having a non-conductive substrate to which a thin film method / thick film method can be applied. The non-conductive substrate has a horizontal main surface and a plurality of side surfaces facing each other, and two of the plurality of side surfaces have a shape that converges toward one point. One of the side surfaces that converge toward one point has an inclined portion of about 40 degrees, and the other side surface has an inclined portion of about 10 degrees. A curved probing tip contact is formed on the non-conductive substrate at the convergence point. The curved probing tip contact has first and second arched surfaces that meet each other, and a conductive material is formed (laminated) thereon.

  The probing chip has a resistive element formed by using a thin film method or a thick film method on one of the opposing horizontal main surfaces of the non-conductive substrate, and one end of the resistive element is Electrically coupled to the conductive material on the curved probing tip contact. The probing chip also has an amplifier circuit, preferably in the form of a buffer amplifier circuit. The amplifier circuit is disposed on one of the opposing horizontal main surfaces of the non-conductive substrate and is electrically coupled to the other end of the resistive element. The resistive element is electrically coupled to the amplifier circuit by wire bonding.

  The conductive material disposed on the curved probing chip is formed of an adhesive layer and a layer of gold or platinum / gold alloy laminated on the adhesive layer. The adhesive layer is preferably formed of a titanium / tungsten alloy.

  A non-conductive substrate having a curved probing tip contact is preferably secured to a carrier formed from an insulating material such as a liquid crystal polymer. A second non-conductive substrate is also secured to the carrier, and the second non-conductive substrate has a grounded coplanar waveguide structure formed thereon. The second non-conductive substrate may be formed from a circuit board material such as FR-4 circuit board material. The amplifying circuit is coupled to a grounded coplanar waveguide structure by a gold bonding wire.

More specifically, concept 1 of the present invention is a probing tip for a signal acquisition probe,
A non-conductive substrate having a horizontal main surface and a plurality of side surfaces facing each other, wherein two of the plurality of side surfaces converge to one point, and a thin film method or a thick film method can be applied;
A curved probing tip contact formed at a converging point of the non-conductive substrate and having first and second arched surfaces that meet at a plane;
And a conductive material formed (laminated and deposited) on the curved probing tip contact.

  The concept 2 of the present invention is a probing tip for a signal acquisition probe according to the concept 1, which is formed on at least one of the thin film method and the thick film method on one of the opposed horizontal main surfaces, It further comprises a resistive element having one end electrically coupled to the conductive material on the curved probing tip contact.

  The concept 3 of the present invention is a probing tip for a signal acquisition probe according to the concept 2, which is formed on one of the opposed horizontal main surfaces and is electrically coupled to the other end of the resistive element. An amplifier circuit.

  The concept 4 of the present invention is the signal acquisition probe probing chip according to the concept 3, wherein the amplifying circuit is a buffer amplifying circuit.

  Concept 5 of the present invention is the signal acquisition probe probing chip according to Concept 3, further comprising a bonding wire for electrically coupling the other end of the resistive element to the amplifier circuit.

  The concept 6 of the present invention is the probing tip for a signal acquisition probe according to the concept 1, in which the conductive material is formed on the curved probing tip contact, and on the adhesive layer. And a conductive layer formed of gold.

  The concept 7 of the present invention is the probing tip for a signal acquisition probe according to the concept 6, wherein the adhesive layer is formed of titanium / tungsten.

  The concept 8 of the present invention is the probing tip for a signal acquisition probe according to the concept 1, in which the conductive material is formed on the curved probing tip contact, and the adhesive layer It is characterized in that it has a platinum gold layer formed on.

  The concept 9 of the present invention is the probing tip for a signal acquisition probe according to the concept 8, wherein the adhesive layer is formed of titanium / tungsten.

  The concept 10 of the present invention is the probing tip for a signal acquisition probe according to the concept 1, wherein one of the converging side surfaces of the non-conductive substrate has an inclination of substantially 40 degrees. Yes.

  The concept 11 of the present invention is the probing tip for a signal acquisition probe according to the concept 10, wherein the other side of the non-conductive substrate converged has an inclination of substantially 10 degrees. It is said.

  The concept 12 of the present invention is the signal acquisition probe probing chip according to the concept 1, further comprising a carrier to which the non-conductive substrate is fixed.

  The concept 13 of the present invention is the probing chip for a signal acquisition probe according to the concept 12, further comprising a second non-conductive substrate fixed to the carrier.

  Concept 14 of the present invention is a signal acquisition probe probing chip according to Concept 13, further comprising a grounded coplanar waveguide structure formed on the second non-conductive substrate.

  The concept 15 of the present invention is a signal acquisition probe probing chip according to the concept 12, wherein the non-conductive substrate is formed of a circuit board material.

  Concept 16 of the present invention is a signal acquisition probe probing chip according to Concept 14, further comprising a gold bonding wire that electrically couples the amplifier circuit to the ground coplanar waveguide structure.

  The objects, advantages and other novel features of the present invention will become apparent from the following detailed description when read in conjunction with the appended claims and drawings.

FIG. 1 is a perspective view of a probing tip for a signal acquisition probe according to the present invention. FIG. 2 is a side view of a probing tip for a signal acquisition probe according to the present invention. FIG. 3 is an exploded perspective view of a support structure and a conductive structure for a signal acquisition probe according to the present invention. FIG. 4 is an enlarged view of the front portion of the probing tip for a signal acquisition probe according to the present invention.

  1 and 2 show a perspective view and a side view of a probing tip 10 for a signal acquisition probe. The probing chip 10 has a substrate 12, which is formed from a rigid, non-conductive material such as fused quartz or ceramic material and is nominally treated at 300 degrees Fahrenheit (about 149 degrees Celsius). Thin film methods requiring temperature can be applied. The substrate has a top main surface 14, a bottom main surface 16, and a plurality of side surfaces 18. The substrate has a nominal width of 0.044 inches (about 1.1 millimeters), a nominal length of 0.060 inches (about 1.5 millimeters), and a nominal thickness of 0.010 inches (about 0.2 millimeters). One of the plurality of side surfaces 18 has an inclined portion 20, and the nominal angle with respect to the left side surface 18 in FIG. 1 is 40 degrees. On the side surface 18 adjacent to the inclined side surface portion 20, there is another inclined portion 22, and the nominal angle with respect to the right side surface 18 in FIG. 1 is 10 degrees. The inclined side surfaces 20 and 22 are formed so as to converge toward the point where the probing tip contact 24 is formed. Alternatively, the substrate 12 may be a thick film method that requires a nominal processing temperature of 850 degrees Celsius.

  The surface of the probing chip contact 24 is curved, and a conductive material is formed thereon (lamination, vapor deposition, etc.). The curved surface includes a first arched surface 26 and a second arched surface 28. The first arched surface 26 has a curve with a nominal radius of 0.000020 inch (0.051 millimeter), and the second arched surface 28 has a curve with a nominal radius of 0.0040 inch (0.10 millimeter). The first arched surface and the surface intersect to form a substantially circular contact. An adhesive layer is formed on the curved probing chip contact 24, and a conductive material is formed (laminated and evaporated) on the adhesive layer. In a preferred embodiment, the adhesive layer is a titanium / tungsten alloy, and a gold conductive layer is formed (laminated or deposited) thereon. Alternatively, the conductive layer may be a platinum gold alloy or similar material with similar properties. A three-dimensional spherical probing tip contact 24 is formed by arched surfaces 26 and 28 where the surfaces meet.

  A thin film or thick film resistive element 30 is formed (laminated, vapor deposited) on the upper major surface 14 of the non-conductive substrate 12. The conductive contacts 32 and 34 are formed (laminated and vapor-deposited) on both ends of the resistive element 30 using a thin film method or a thick film method. The electrical contacts 32 and 34 are formed together with an adhesive layer of titanium / tungsten alloy, and a conductive layer is formed on the adhesive layer. Electrical contact 32 electrically connects curved probing tip contact 24 to resistive element 30, and electrical contact 34 provides electrical for wire bonding resistive element 30 to integrated circuit die 36. Functions as a contact pad. The integrated circuit die 36 is fixed to the upper main surface 14 of the non-conductive substrate 12 using a non-conductive adhesive such as an epoxy resin. The integrated circuit die 36 includes amplifier circuitry and bonding pads 38 and 40. The amplifier circuit is preferably a buffer amplifier circuit. A conductive wire 42 is bonded to one of the plurality of bonding pads 38 and the electrical contact 34, thereby electrically connecting the resistive element 30 to the input terminal of the amplifier circuit on the integrated circuit die 36. . The other bonding pad 38 is coupled to the output terminal of the amplifier circuit on the integrated circuit die 36.

  Alternatively, the integrated circuit die 36 may be secured to the upper major surface 14 of the non-conductive substrate 12 using flip-chip technology. A plurality of solder pads are formed on the upper major surface 14, and one solder pad is electrically connected to the electrical contacts 34 of the resistive element 30 through conductive traces disposed on the upper major surface 14. Combined. When fixed, the integrated circuit die 36 is provided with solder balls (solder mass) formed on the integrated circuit die 36 in a form corresponding to the solder pads on the upper major surface 14. A solder ball corresponding to a solder pad that is electrically coupled to resistive element 30 is electrically coupled to an input terminal of the amplifier circuit. The plurality of solder balls of the integrated circuit die 36 are in positions corresponding to the solder pads and are heated to secure the integrated circuit die to the upper major surface 14 of the non-conductive substrate 12. The integrated circuit die 36 is mounted on the upper main surface 14 while the solder ball is in a molten state, whereby the integrated circuit die 36 is fixed on the upper main surface 14.

  FIG. 3 is an exploded perspective view of the support structure for the signal acquisition probe probing tip 10. The support structure has a substantially triangular carrier 50, and the carrier 50 has a recessed portion 54 adjacent to the raised pedestal portion 52. The carrier 50 is composed of a low dielectric, high strength non-conductive material such as a liquid crystal polymer, and may be formed by, for example, an injection molding method. The non-conductive substrate 12 of the probing chip 10 is fixed to the pedestal 52 using a non-conductive adhesive such as an epoxy resin. The curved probing tip contact 24 extends beyond the tip of the pedestal 52 to allow the curved probing tip contact 24 to engage a test point on the device under test. At the opposite end (back side in FIG. 3) of the pedestal 52, there is a vertical wall 56 that is a boundary with the recess 54. The second non-conductive substrate 58 is formed of a non-conductive material such as an FR-4 circuit board member, a ceramic member, etc., and has a similar external shape to the concave portion 54 so that it can be fixed on the concave portion 54. It has become. The substrate 58 has a top main surface 60 and a bottom main surface 62, and a front surface 64 that contacts the vertical wall 56 of the pedestal 52. The substrate 65, which is a conductive layer, is disposed on the bottom major surface 62 of the substrate 58 as a ground (ground) layer. A notch (cut) 66 is formed at the end of the substrate 58 on the opposite side (the back side in FIG. 3) so as to receive the coaxial signal connector 68. The substrate 58 has a thickness adjusted so that the upper main surface 60 and the upper main surface 14 of the non-conductive substrate 12 of the probing chip 10 are aligned on the same surface. The transmission structure 70 is disposed on the upper main surface 60 of the substrate 58. The transmission structure 70 is preferably a grounded coplanar transmission structure and has a conductive trace 72 electrically connected to the central signal conductor 74 of the coaxial signal connector 68. Two ground planes 76 are disposed adjacent to both sides of the conductive trace 72. The ground plane 76 is electrically connected to a tab 78 extending from the coaxial signal connector 68. A recess 80 is formed at the end opposite to the pedestal 52 of the carrier 50 and receives the lower part of the coaxial signal connector 68. The upper cover 82 is fixed to the carrier 50 using a known fixing means such as ultrasonic welding or an adhesive such as an epoxy resin.

  FIG. 4 is a detailed enlarged view of the front portion of the probing tip 10. Conductive wires 90 extend from the plurality of bonding pads 38 of the integrated circuit die 36 to the corresponding conductive traces 72 and ground plane 76 of the transmission structure. Conductive wire 90 connects bonding pad 38 to conductive trace 72 and ground plane 76 by wire bonding. Conductive wires (not shown for simplicity) extend from the plurality of bonding pads 40 of the integrated circuit die 36 to conductive traces (not shown for simplicity) on the substrate 58 for power and communication. The signal is supplied to the integrated circuit die 36. In another example embodiment using flip chip technology, bonding pads 38 and 40 are formed on the exposed surface of the integrated circuit die 36 and are connected to conductive traces 72, ground planes via conductive wires. 76 and coupled to conductive traces that provide power and communication signals.

  While specific embodiments of the present invention have been illustrated and described for purposes of illustration, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention.

10 Probing tips
12 Non-conductive substrate 14 Upper main surface 16 Bottom main surface 18 Side surface (plural)
20 Inclined portion 22 Inclined portion 24 Probing tip contact 26 First arched surface 28 Second arched surface 30 Resistive element 32 Conductive contact 34 Conductive contact 36 Integrated circuit die 38 Bonding pad 40 Bonding pad 42 Conductive wire 50 Carrier 52 Pedestal portion 54 Recessed portion 56 Vertical wall 58 Second non-conductive substrate 60 Upper main surface 62 Bottom main surface 65 Conductive substrate (ground layer)
66 Notch 68 Coaxial signal connector 70 Transmission structure 72 Conductive trace 74 Center signal conductor 76 Ground plane 78 Tab 80 Recess 82 Top cover 90 Conductive wire

Claims (3)

A non-conductive substrate having a main surface and a plurality of side surfaces opposed to each other, two of the plurality of side surfaces being converged to one point, and applying a thin film method or a thick film method;
A curved probing tip contact formed at a converging point of the non-conductive substrate and having first and second arched surfaces that meet at a plane;
A probing tip for a signal acquisition probe, comprising: a conductive material formed on the curved probing tip contact.   Formed on one of the opposed main surfaces using at least one of a thin film method or a thick film method, and one end portion is electrically coupled to the conductive material on the curved probing tip contact The probing tip for a signal acquisition probe according to claim 1, further comprising a resistive element.   3. The probing tip for a signal acquisition probe according to claim 2, further comprising an amplifier circuit formed on one of the opposing main surfaces and electrically coupled to the other end of the resistive element.

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