TWI407106B - High frequency cantilever probe card - Google Patents

Abstract

A high-frequency cantilever probe card, comprising a circuit board, an insulated pin base, plural signal pins, and at least one ground pin, wherein the signal pins and the ground pins are fixed at the insulated pin base and electrically connected with signal circuit of the circuit board and the ground circuit, respectively. Also, each signal pin has a probe body and a conductive film, the conductive film is coated upon the probe body along its axial direction in an electrical isolation manner so as to reduce the capacitive coupling area and decrease the insulating material thickness between the probe body and the conductive film, thereby reducing the radial cross-sectional area of the signal pins in order to help closer arrangement of the signal pins.

Description

High frequency cantilever probe card

The present invention relates to a probe device for electrical detection, and more particularly to a high frequency cantilever probe card.

The high-frequency cantilever probe card 10 shown in the first and second figures is used for transmitting a test signal of a detector to an electronic component for electrical detection, wherein the second figure is the direction of 2-2 of the first figure. Cutaway view. The probe card 10 includes a circuit board 12, a probe holder 14 and a plurality of coaxial probes 16. The circuit board 12 is provided with a plurality of coaxial wires 12a electrically connected to the coaxial probe 16, and the coaxial probe 16 is provided by a coaxial probe 16 The probe body 16a, an insulating layer 16b and a conductive shaft tube 16c, wherein the probe body 16a is used for high-frequency signal transmission, and the conductive shaft tube 16c is electrically connected to the ground potential for the purpose of making the coaxial probe 16 good. And effective high-frequency signal transmission performance.

The impedance matching between the detecting machine, the probe card 10 and the electronic component is related to the quality of the high-frequency telecommunications test project, and in order to effectively transmit the high-frequency signal, the coaxial probe 16 of the conventional probe card 10 must have The impedance of the detector and the electronic component is the same or close to the above purpose, and the problem of impedance mismatch caused by the parasitic capacitance effect between the probe body 16a and the conductive shaft tube 16c causes impedance mismatch, so that the coaxial probe 16 The thickness h1 of the insulating layer 16b must be designed in a proportional manner according to the size of the capacitive coupling area between the probe body 16a and the conductive shaft tube 16c, that is, the coaxial probe 16 for high frequency signal transmission. When the capacitive coupling area is large, the thickness h1 of the insulating layer 16b must be increased accordingly, so that the impedance matching can be achieved; however, since the capacitive coupling area of the coaxial probe 16 is large, the thickness of the insulating layer 16b is h1. With a relative increase, the radial cross-sectional area of the coaxial probe 16 at the combined portion of the probe body 16a, the insulating layer 16b and the conductive shaft tube 16c is difficult to be reduced, that is, the diameter of the coaxial probe 16 is too large. As a result, the distance between adjacent coaxial probes 16 of the probe card 10 can no longer be reduced, in other words, the existing probe card 10 is applied to detect finer and finer pitches. In the case of electronic components, the coaxial probe 16 of the probe card 10 will be difficult to align with the electronic components, which highlights the tendency of the existing probe card 10 to cope with the rapid development of the technology.

In order to solve the above problem that the thickness of the insulating layer must be increased due to the large coupling area of the capacitor, the manufacturer has changed the probe structure for transmitting the high-frequency signal to the first, based on the proportional relationship between the capacitive coupling area and the thickness of the insulating layer. As shown in FIG. 3, the probe 20 includes a signal pin 22, a grounding wire 24 and an insulating outer tube 26. The signal pin 22 and the grounding wire 24 are respectively covered by an insulating material 22a, 24a. The capacitive coupling area between the pin 22 and the ground line 24 is small, such that the only insulation distance between the pins 22 and the like is the total thickness h2 of the insulating material 22a and the insulating material 24a. The insulating outer tube 26 wraps the signal pin 22 and ground. Line 24; the foregoing structure is reduced by the overall radial cross-sectional area of the probe 20 (the basis of which is based on the probe 20 being required to be impedance matched at 50 ohms, the probe 20 cross-sectional area is the first diagram of the conventional technique of coaxial probe The one-third of the cross-sectional area of the needle 16 allows the probe card having the probes 20 to be used in applications where the electronic components are arranged more closely. Although the structure of the probe 20 described above makes the application of the probe card wider, in the era of rapid development of the technology, anyone who can master more sophisticated technology will be a winner.

In view of the above, it is a primary object of the present invention to provide a high frequency cantilever type probe card which can be used for electrical detection in a case where electronic components are arranged more closely.

In order to achieve the above object, the high frequency cantilever probe card provided by the present invention comprises a circuit board, a socket, a plurality of signal pins and at least one grounding pin, wherein the circuit board is provided with a plurality of signal circuits and a plurality of grounding circuits. The needle holder is made of an insulating material and is coupled to the circuit board. The signal pins are fixed to the needle holder and electrically connected to the signal circuit of the circuit board. Each of the signal pins has a probe body and a body electrically connected to the probe body. Conductive film, the conductive film is disposed along the axial direction of the probe body, and does not completely cover the probe body, and the grounding pin is also fixed on the needle seat, and the conductive film and circuit board of the signal pin The ground circuit is electrically connected.

In order that the present invention may be more clearly described, the preferred embodiments are illustrated in the accompanying drawings. 4 to 6 are high-frequency cantilever probe cards 100 according to a preferred embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line 5-5 of the fourth figure. The sixth figure is a schematic diagram of the signal pin and the ground pin arrangement of the probe card. The probe card 100 can be applied to a signal connection structure of a test object such as a semiconductor die, an integrated circuit or a signal carrying substrate of other electronic circuits. The detection includes a circuit board 30, a socket 40, a plurality of signal pins 50, at least one grounding pin 60 and a plurality of metal wires 70, wherein the circuit board 30 is a disk-shaped printed circuit board having a The upper surface 30a and the lower surface 30b are electrically connected to a detecting device (not shown). The lower surface 30b is fixed to the needle holder 40, and the circuit board 30 has a complex signal circuit 32 and a plurality of grounding circuits 34. The signal circuit 32 is for transmitting the test signal of the detector to the signal pin 50, and the ground circuit 34 is for maintaining the ground potential.

The hub 40 is made of a material having good insulating properties, and is provided on the lower surface 30b of the circuit board 30.

The signal pins 50 are fixed to the needle holder 40 in a spaced arrangement, and each of the signal pins 50 is composed of a probe body 52, an insulating layer 54 and a conductive film 56. The probe body 52 has a The cantilever 52a, one end of the cantilever 52a is electrically connected to the signal circuit 32 of the circuit board 30, and the other end is bent to form a needle tip 52b. The needle tip 52b is a test pad for touching the object to be tested (not shown); the insulating layer 54 In the present embodiment, a material having good insulating properties is formed around and completely covering the surface of the cantilever 52a of the probe body 52. The insulating layer 54 has an outer surface 54a; the conductive film 56 is made of a material having conductive properties. The axial direction of the cantilever 52a is coated on the outer surface 54a of the insulating layer 54. As shown in the fifth figure, the conductive film 56 does not completely cover the insulating layer 54, that is, only the portion of the outer surface 54a of the insulating layer 54 is shielded. . In general, the conductive film 56 is formed on the outer surface 54a of the insulating layer 54 by electroplating or sputtering, or the conductive film 56 is adhered to the outer surface 54a of the insulating layer 54 using an adhesive, or otherwise achieved; It is emphasized that the cross-sectional area of the radial cross section of the probe body 52 of the signal pin 50, the insulating layer 54 and the conductive film 56 (as shown in FIG. 5) is sequentially larger than the insulating body 54 of the probe body 52. The insulating layer 54 is larger than the conductive film 56.

The grounding pin 60 is a metal conductor fixed to the hub 40 and electrically connected to the grounding circuit 34 of the circuit board 30. In this embodiment, each grounding pin 60 is coupled with a plurality of signal pins 50. A probe set is formed. The grounding pin 60 and the signal pin 50 are fixed to the hub 40 in a spaced arrangement. The grounding pin 60 and the signal pin 50 do not interfere with each other, and the matching ratio is designed according to the needs of use.

As shown in the sixth and seventh figures, the metal wires 70 are respectively connected to the conductive film 56 of the adjacent signal pin 50, and the grounding pin 60 adjacent to the signal pin 50 is connected. The conductive film 56 of the signal pin 50 and the ground pin 60 are electrically connected to the ground potential.

The above is a structural description of the probe card 100 according to a preferred embodiment of the present invention. In the case of impedance matching between the detector and the object to be tested, the probe body 52 of each of the signal pins 50 is connected to the circuit board 30. The signal circuit 32 is electrically connected to transmit the high frequency signal to the object to be tested. The conductive film 56 on each of the signal pins 50 is only partially and insulatedly disposed above the probe body 52 because it does not completely surround the probe body 52. Therefore, the capacitive coupling area between the conductive film 56 and the probe body 52 is lowered, in other words, the thickness h3 of the insulating layer 54 does not need to be increased, which causes the signal pin 50 to be in the cantilever 52a of the probe body 52, the insulating layer 54 and the conductive The radial cross-sectional area of the combined portion of the membrane 56 is reduced, which is much smaller than the radial cross-sectional area of the conventional coaxial probe 16 or probe 20 shown in the second and third figures of the prior art (the basis of which is based on the signal) The needle 50 is required to have an impedance matching of 50 ohms, and the cross-sectional area of the signal pin 50 of the present invention is about one-ninth of the cross-sectional area of the first image signal of the conventional technique, which is about the second figure of the conventional technique. One-third of the cross-sectional area), therefore, The signal pins 50 of the probe card 100 of the invention are arranged more closely, and are used for the electrical detection in the case where the electronic components are closely arranged, so as to weaken the signal interference to maintain the high-frequency signal transmission quality. The grounding circuit can be realized by connecting the metal wires 70 to the grounding pins 60 in series with each other between the conductive films 56 of the signal pins 50.

Secondly, the signal pin 50 of the probe card 100 of the present invention has a rigid probe body 52 as a main supporting structure, which not only facilitates the stable bonding of the insulating layer 54 and the conductive film 56, but also provides sufficient mechanical strength. To cope with the repeated use of the actual test and possible pressure deformation.

In addition, the insulating layer of the present invention is formed in the form shown in the eighth embodiment except that the above-mentioned completely covering manner, that is, the insulating layer 54' is along the axis of the cantilever 52a in an incompletely wrapped manner. To cover the surface of the cantilever 52a, the insulating layer 54' also has an outer surface 54a' to provide a conductive film 56 which is axially covered thereon. This structure reduces the radial cross-sectional area of the signal pin and contributes to the tightness of the signal pin. arrangement.

The probe card 101 disclosed in the ninth embodiment is another preferred embodiment of the present invention. In addition to all the components of the above embodiments, the probe card 101 further includes at least one conductive medium 80, and the conductive medium 80 The metal wires 70 are connected to each other to electrically connect the conductive film 56 of the signal pin 50 to the ground pin 60.

The above description is only for the preferred embodiments of the present invention, and the equivalent structures and manufacturing methods of the present invention and the scope of the patent application are intended to be included in the scope of the present invention.

10. . . Probe card

12. . . Circuit board

12a. . . Coaxial wire

14. . . Needle seat

16. . . Coaxial probe

16a. . . Probe body

16b. . . Insulation

16c. . . Conductive shaft tube

H1. . . thickness

20. . . Probe

twenty two. . . Signal pin

22a. . . Insulation Materials

twenty four. . . Ground wire

24a. . . Insulation Materials

26. . . Insulated outer tube

H2. . . thickness

100 (101). . . Probe card

30. . . Circuit board

30a. . . Upper surface

30b. . . lower surface

32. . . Signal circuit

34. . . Ground circuit

40. . . Needle seat

50. . . Signal pin

52. . . Probe body

52a. . . cantilever

52b. . . Tip

54 (54’). . . Insulation

54a (54a’). . . The outer surface

56. . . Conductive film

H3. . . thickness

60. . . Grounding pin

70. . . metal wires

80. . . Conductive medium

The first figure is a schematic diagram of a probe card with a coaxial probe.

The second figure is a cross-sectional view taken in the direction of 2-2 of the first figure.

The third figure is a cross-sectional view of another conventional probe.

The fourth figure is a schematic view of a probe card according to a preferred embodiment of the present invention.

The fifth figure is a cross-sectional view taken in the direction of 5-5 of the fourth figure.

FIG. 6 is a schematic view showing the arrangement of the signal pins and the ground pins of the probe card according to the above preferred embodiment of the present invention.

The seventh figure is a cross-sectional view showing the electrical connection structure between the signal pin and the ground pin.

The eighth figure is a cross-sectional view showing that the insulating layer is fabricated in an incompletely coated manner.

Figure 9 is a schematic view of a probe card according to another preferred embodiment of the present invention.

50. . . Signal pin

56. . . Conductive film

60. . . Grounding pin

70. . . metal wires

Claims (16)

A signal pin for a probe card, comprising: a probe body having a cantilever and forming a tip on one end of the cantilever; and an insulating layer formed by attaching an insulating material to the cantilever surface of the probe body, The insulating layer has an outer surface; a conductive film attached to the outer surface of the insulating layer and not completely covering the insulating layer; wherein: the probe body, the insulating layer and the conductive film are in the same radial direction The cross-sectional area of the cross-section is such that the probe body is larger than the insulating layer, and the insulating layer is larger than the conductive film. The signal pin for a probe card according to claim 1, wherein the insulating layer completely covers the cantilever surface of the probe body, and the conductive film is coated on an outer surface of the insulating layer along an axial direction of the cantilever. The signal pin for a probe card according to claim 1, wherein the insulating layer is coated on the cantilever surface along an axial direction of the cantilever in an incompletely wrapped manner, and the conductive film is also axially covered. The outer surface of the insulating layer. A cantilever probe set comprising: a signal pin comprising: a probe body having a cantilever and forming a tip at one end of the cantilever; and an insulating layer attached to the cantilever surface of the probe body by an insulating material Forming, the insulating layer has an outer surface; a conductive film attached to an outer surface of the insulating layer and not completely covering the insulating layer; A grounding pin is electrically connected to the conductive film of the signal pin. The cantilever probe set according to claim 4, wherein the insulating layer of the signal pin completely covers the cantilever surface of the probe body, and the conductive film is coated outside the insulating layer along the axial direction of the cantilever surface. The cantilever probe set according to claim 4, wherein the insulating layer of the signal pin is coated on the cantilever surface along the axial direction of the cantilever in an incompletely wrapped manner, and the conductive film is also axially Covered on the outer surface of the insulating layer. The cantilever probe set according to claim 4, wherein the grounding pin and the conductive film of the signal pin are electrically connected by a metal wire in series. The cantilever probe set according to claim 4, further comprising a conductive medium electrically connected to the conductive film of the signal pin and the ground pin. The cantilever probe set according to claim 4, wherein a cross-sectional area of the probe body of the signal pin, the insulating layer and the conductive film at the same radial section is sequentially larger than the needle body An insulating layer that is larger than the conductive film. A probe card comprising: a circuit board on which a plurality of signal circuits and a plurality of ground circuits are disposed; a needle holder is made of an insulating material and coupled to the circuit board; and a plurality of signal pins are fixed to the needle And electrically connected to the signal circuit of the circuit board, each of the signal pins has a probe body and at least one conductive film, the conductive film is electrically connected to the axial direction of the probe body, and the conductive The film does not completely cover the probe body; and at least one grounding pin is also fixed to the needle holder and the conductive film of the signal pin and the The grounding circuit of the circuit board is electrically connected. The probe card of claim 10, wherein the probe body of the signal pin comprises a cantilever and a tip, an insulating layer is attached to the cantilever surface of the probe body and has an outer surface, and the conductive film is attached. The outer surface of the insulating layer is not completely covered with the insulating layer. The probe card of claim 11, wherein the insulating layer completely covers the cantilever surface of the probe body, and the conductive film is coated on an outer surface of the insulating layer along an axial direction of the cantilever. The probe card of claim 11, wherein the insulating layer is coated on the cantilever surface along an axial direction of the cantilever in an incompletely coated manner, and the conductive film is also axially coated on the insulating layer. The outer surface. The probe card of claim 10, wherein the grounding pin and the conductive film of the signal pins are electrically connected by a metal wire. The probe card of claim 10, further comprising a conductive medium electrically connected to the conductive film of the signal pin and the ground pin. The probe card of claim 11, wherein the probe body of the signal pin, the cross section of the radial cross section of the insulating layer and the conductive film are sequentially larger than the insulating layer. The insulating layer is larger than the conductive film.