TWI444625B - High frequency probe card - Google Patents

Description

High frequency probe card

The present invention relates to probes for measuring the electrical properties of electronic products, and more particularly to a high frequency probe card.

The main purpose of the probe card is to directly contact the solder pad or bump on the object to be tested (such as a wafer) to extract the signal of the object to be tested (wafer), and then cooperate with the peripheral test instrument and software. Control to achieve automated measurement purposes, and further screening out defective products.

However, there are many factors affecting the measurement results, one of which is whether the impedance between the probe card, the test instrument and the object to be tested can be matched, and the factors affecting the impedance matching are, for example, set on the measurement signal transmission path. The number of pads or bumps, the greater the number will increase the impedance value is not conducive to signal transmission; or, the distance between adjacent probes is often one of the factors affecting the impedance matching. Another factor that can affect the measurement results is the electrical conductivity of the probe itself. In other words, in order to obtain good and accurate measurement results, it is a viable option to effectively control the impedance matching between the probe card, the test instrument and the test object, and to select a probe with good electrical conductivity. In addition, if the two can be combined, it will be more beneficial to improve measurement accuracy.

Secondly, while the electronic products are becoming thinner and lighter, the probe card, which is known to place a large number of probes on the same plane (or the same height), will be issued. It is difficult to effectively align the probes with the object to be tested. For this reason, if the probes are effectively changed under the premise of impedance matching, the probe card can be applied to the measurement to be more refined and refined. And the fine pitch of the test object is arranged.

In view of this, the main object of the present invention is to provide a high-frequency probe card, which can improve electrical conductivity and improve measurement accuracy.

A secondary object of the present invention is to provide a high-frequency probe card which has a good impedance matching effect and can be applied to an occasion where the object to be tested is arranged more closely for electrical measurement.

In order to achieve the above object, the high frequency probe provided by the present invention comprises a signal pin and an impedance matching structure. The signal pin includes a probe body, and a high conductivity layer covers the surface of the probe body; the impedance matching structure is disposed in parallel with the signal pin and electrically isolated from the high conductivity layer.

In one embodiment, the impedance matching structure includes a metal line and an insulating layer, the metal line is outside the signal pin, and the insulating layer covers the metal line.

In another embodiment, the impedance matching structure is a metal sleeve including an insulating inner layer and a metal surface, and the signal pin passes through the insulating inner layer.

Further, in accordance with the above concept, the high conductivity layer is selected from the group consisting of gold, silver, copper, and aluminum materials. And the probe body of the signal pin has a needle tip, a needle body and a needle tail, and the high conductivity layer is coated on the needle body of the probe body.

The invention further provides a high frequency probe card comprising a circuit board, a signal pin layer and a ground potential layer. The signal pin layer is disposed on a surface of the circuit board and includes at least one signal pin, the signal pin has a probe body and a high conductivity layer, wherein the high conductivity layer covers the surface of the probe body The ground potential layer is disposed above or below the signal pin layer, and includes an electrical grounding pin and an impedance matching structure, wherein the impedance matching structure is disposed in parallel with the signal pin, and is electrically isolated from each other .

In one embodiment, the impedance matching structure is a metal line that is adjacent to but not in contact with the signal pin. Preferably, the ground potential layer further includes a conductive member electrically connected to the metal line and the ground pin.

In one embodiment, the high frequency probe card includes two or more signal pin layers, and the ground potential layer is located between the two signal pin layers, and the impedance matching structure includes two or more metal wires. Don't be adjacent to a signal pin.

In another embodiment, the high frequency probe card includes a first to fourth signal pin layer, and at least two ground potential layers, wherein a ground potential layer is between the first and second signal pin layers, and A ground potential layer is between the third and fourth signal pin layers.

Thereby, the high-frequency probe of the present invention has good electrical conductivity, and in the case of effectively controlling the impedance matching, the probe card having the high-frequency probe can be used for measurement to improve the measurement result. Precision.

In order that the present invention may be more clearly described, the preferred embodiments are illustrated in the accompanying drawings.

1 to 3 show a high-frequency probe card 100 according to a first preferred embodiment of the present invention. A plurality of signal contacts 10a and a plurality of ground contacts 10b are disposed on a bottom surface of a circuit board 10, and a plurality of signals are provided. One end of the pin 12 is connected to the corresponding signal contact 10a, and the ground pin 14 is electrically connected to the ground contact 10b.

The high-frequency probe card 100 is suitable for measuring more delicate and fine objects to be tested, and the signal pins 12 and the grounding pins 14 are designed in a layered manner, that is, the probes for different purposes are placed. In the same plane (or the same height), in the embodiment, the high-frequency probe card 100 is divided into a signal pin layer 12A for transmitting high-frequency signals and a ground potential layer 14A, and has two layers of signal pin layers. For example, the ground potential layer 14A of 12A and one layer is located between the two signal pin layers 12A.

1 and 4, each of the signal pins 12 of the signal pin layer 12A is composed of a probe body 121 and a high conductivity layer 122. The probe body 121 has a needle tip 121a, a needle body 121b and a needle tail 121c for contacting an object to be tested (not shown). The needle tail 121c is a signal contact point 10a with the circuit board 10. The high-conductivity layer 122 is made of a group of gold, silver, copper, and aluminum materials. In this embodiment, silver is taken as an example, and the high-conductivity layer 122 is coated. The needle body 121b of the probe body 121 is exposed to expose the needle tip 121a to contact the object to be tested. Since the surface of each of the signal pins 12 has a skin effect in a high-frequency measurement environment, and the surface of each of the signal pins 12 has the high-conductivity layer 122, the electrical conductivity of the signal pin 12 is improved.

In addition to the grounding pin 14, the ground potential layer 14A includes a conductive member 16 and an impedance matching structure. In this embodiment, the conductive member 16 is exemplified by a copper foil, and the impedance matching structure is two metal wires 18, and each metal wire 18 is parallel to a corresponding signal pin 12. The conductive member 16 is disposed in an unfolded manner, and the grounding pin 14 and one end of each of the metal wires 18 are respectively disposed on the surface of the conductive member 16, thereby achieving electrical connection; and for each of the metal wires 18, The signal pin 12 is disposed in proximity to but not in contact with the corresponding signal pin 12, which not only ensures electrical isolation between the signal pin 12 and the metal wire 18, but also causes the signal pin 12 to be good because the metal wire 18 is connected to the ground potential. Impedance matching effect.

Moreover, an insulating sleeve 20 is disposed on the outer side of the two adjacent metal wires 18 and the signal pin 12 to maintain the spacing between the signal pin 12 and the metal wire 18.

Since the high-frequency probe card 100 pairs the signal pin layer 12A for transmitting the high-frequency signal and the ground potential layer 14A including the metal wire 18 for impedance matching, the layer is made by layering, so that the space is skillfully utilized. The distance between the signal pins 12 can be measured in a close proximity to each other in a case where the objects to be tested are arranged more closely without being interfered with each other.

In this embodiment, the impedance matching effect between the high-frequency probe card 100, the test instrument, and the object to be tested is effectively controlled by the setting of the impedance matching structure, and the high conductivity layer 122 is present on the surface of each of the signal pins 12. In addition, the ability to transmit high-frequency signals and the transmission quality are enhanced, so that the high-frequency probe card 100 can improve the accuracy of the measurement results when measuring. Please refer to FIG. 5, which is a comparison diagram of a frequency (freq) and an energy loss (ie, attenuation value (dB)) of the signal pin 12 of the present embodiment having good electrical conductivity. The line is the measurement result of the signal pin 12, and the lower line is the measurement result of the general use of the 铼 tungsten needle as the signal pin. For example, the case of the frequency at 2.5 GHz can be found to represent the m1 point of the signal pin 12. The corresponding attenuation value (dB) is about 4.6, and the attenuation value (dB) corresponding to the m2 point representing the 铼 tungsten needle is about 7.1. The significant difference between the two data indicates the surface coating of this embodiment. The signal pin 12, which is made of a silver material and has a high conductivity layer 122, greatly enhances the electrical conductivity of the high frequency signal.

It should be noted that, in addition to the combination of the grounding pin 14, the conductive member 16 and the metal wire 18 shown in FIG. 3, the structure for generating the impedance matching effect of the present invention may have the following structural changes, wherein: FIG. 6 The impedance matching structure of the second preferred embodiment is also disposed in parallel with the signal pin 12, and includes a metal wire 30 and an insulating layer 32. The metal wire 30 is covered by the insulating layer 32, and The signal pin 12 remains electrically isolated.

The impedance matching structure of the third preferred embodiment shown in FIG. 7 is a metal sleeve 40. The metal sleeve 40 includes an insulating inner layer 42 and a metal surface layer 44, wherein the signal pin 12 passes through the The insulating inner layer 42, in other words, the metal sleeve 40 is disposed coaxially with the signal pin 12.

It should be noted that the number of layers of the signal pin layer and the ground potential layer is not limited to the above, and may be appropriately increased or decreased according to requirements to meet the actual use requirements. The above is only a preferred embodiment of the present invention, and equivalent structural changes to the scope of the present invention and the scope of the claims are intended to be included in the scope of the present invention.

100‧‧‧High frequency probe card

10‧‧‧ boards

10a‧‧‧ Signal contacts

10b‧‧‧ Grounding contacts

12A‧‧‧ Signal Layer

12‧‧‧Signal needle

121‧‧‧ probe body

121a‧‧‧ needle tip

121b‧‧‧ needle body

121c‧‧‧needle tail

122‧‧‧High conductivity layer

14A‧‧‧ Ground potential layer

14‧‧‧ Grounding pin

16‧‧‧Electrical parts

18‧‧‧Metal wire

20‧‧‧Insulation sleeve

30‧‧‧Metal wire

32‧‧‧Insulation

40‧‧‧Metal casing

42‧‧‧Insulated inner layer

44‧‧‧Metal surface

1 is a cross-sectional view showing a high frequency probe card according to a first preferred embodiment of the present invention;

2 is a top plan view showing the high frequency probe card of the above preferred embodiment;

Figure 3 is a cross-sectional view taken along line 3-3 of Figure 2;

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 2;

Figure 5 is a comparative diagram illustrating the energy loss of the signal pin of the present invention and a general xenon tungsten needle;

Figure 6 is a cross-sectional view showing the relationship between the impedance matching structure and the signal pin of the second preferred embodiment of the present invention;

Figure 7 is a cross-sectional view showing the relationship between the impedance matching structure and the signal pin of the third preferred embodiment of the present invention.

100‧‧‧High frequency probe card

10‧‧‧ boards

10a‧‧‧ Signal contacts

10b‧‧‧ Grounding contacts

12‧‧‧Signal needle

121‧‧‧ probe body

121a‧‧‧ needle tip

121b‧‧‧ needle body

121c‧‧‧needle tail

122‧‧‧High conductivity layer

14‧‧‧ Grounding pin

16‧‧‧Electrical parts

18‧‧‧Metal wire

20‧‧‧Insulation sleeve

Claims (4)

A high frequency probe card comprising: a circuit board; a signal pin layer disposed on a surface of the circuit board and including at least one signal pin, the signal pin having a probe body and a high conductivity layer, wherein the signal pin The high conductivity layer covers the surface of the probe body; a ground potential layer is disposed above or below the signal pin layer, and includes an electrical grounding pin and an impedance matching structure, wherein the impedance matching structure and The signal pins are arranged in parallel and are electrically isolated from each other. The high frequency probe card of claim 1, wherein the impedance matching structure is a metal wire adjacent to but not contacting the signal pin. The high frequency probe card of claim 2, wherein the ground potential layer further comprises a conductive member electrically connected to the metal line and the ground pin. The high frequency probe card of claim 1 includes two or more signal pin layers, and the ground potential layer is located between the two signal pin layers, and the impedance matching structure includes more than two metal wires. Each adjacent to the signal pin.