JP2010038726A - Probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the high-frequency characteristics of internal connecting pins by suppressing variations in the characteristic impedance of the internal connecting pins. <P>SOLUTION: A probe card includes a main substrate 10 in which a large number of internal electrodes 15 are formed in its lower surface; a contact unit 20 in which a large number of contact probes 21 are formed in its lower surface and a large number of internal electrodes 25 are formed in its upper surface; a large number of the internal connecting pins 30 arranged between the main substrate 10 and the contact unit 20 for making the internal electrodes 15 and 25 conduct; and an impedance adjustment plate 31 arranged between adjacent internal connection pins 30. Accordingly, it is possible to adjust the characteristic impedance of the internal connection pins 30 and improve the high-frequency characteristics of a probe card. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a probe card, and more particularly, to adjust characteristic impedance of an internal connection pin in a probe card in which a contact unit on which a large number of contact probes are formed and a main board are connected using internal connection pins. For the structure.

  In general, a probe device is used for electrical characteristic inspection performed in a manufacturing process of a semiconductor device. The probe device brings a probe card and a semiconductor wafer close to each other with a large number of contact probes formed on the probe card and a large number of electrode pads formed on the semiconductor wafer facing each other. Is a device that elastically contacts with each other. In this way, by bringing a large number of contact probes into contact with the corresponding electrode pads, the minute electrode pads formed on the semiconductor wafer can be brought into conduction with an external device such as a tester.

  The probe card performs an electrical property test of the inspection object by inputting the electric signal generated by the tester to the inspection object and transmitting the electric signal output from the inspection object to the tester. For this reason, a frequency characteristic corresponding to the operation speed of the inspection object is required. If a recent integrated circuit such as a DRAM is to be inspected, a signal in a frequency band of about 1.6 GHz must be transmitted, and there is a demand for improving the high frequency characteristics of the probe card.

  In order to improve the high frequency characteristics, it is necessary to suppress the dielectric loss in the probe card and to suppress the reflection. Since the reflection of the electric signal occurs at the characteristic impedance discontinuity on the transmission line, it is necessary to match the characteristic impedance of each transmission path. That is, the characteristic impedance of each transmission line in the probe card needs to match the characteristic impedance of the input / output terminals of the tester.

  The present invention has been made in view of the above circumstances, and an object thereof is to improve the high-frequency characteristics of a probe card. In particular, an object is to improve the high-frequency characteristics of the probe card by adjusting the characteristic impedance of the internal connection pin that conducts the main substrate and the contact unit and suppressing reflection at both ends of the internal connection pin.

  The probe card according to the first aspect of the present invention includes a main board having two or more first electrodes formed on the lower surface, and two or more second electrodes formed on the upper surface facing the first electrode, and electrically connected to the second electrodes. A contact unit having two or more contact probes formed on the lower surface, two or more internal connection pins arranged between the main substrate and the contact unit and conducting the first electrode and the second electrode, and a main of the internal connection pins And an impedance adjustment plate arranged to face the surface.

  With such a configuration, the capacitance of the internal connection pin can be set to a constant value according to the distance from the internal connection pin to the impedance adjustment plate. Therefore, if the distance is appropriately determined, the characteristic impedance of the internal connection pin can be set to a desired value, and the high frequency characteristics of the probe card can be improved. In particular, the capacitance can be effectively adjusted by making the main surface of the internal connection pin face the impedance adjustment plate.

  The main surface of the internal connection pin refers to a surface having the largest area when the shape of the internal connection pin is projected onto a plane. For example, when the internal connection pin is formed by bending an elongated wire rod on a plane, the curved plane is the main surface.

  In the probe card according to the second aspect of the present invention, in addition to the above configuration, two or more internal connection pins are arranged in a straight line, and each main surface of these internal connection pins is opposed to one impedance adjustment plate. Yes. With such a configuration, the characteristic impedance of two or more internal connection pins can be set to a desired value using one impedance adjustment plate.

  In the probe card according to the third aspect of the present invention, in addition to the above configuration, the impedance adjustment plates parallel to each other are arranged so as to sandwich the array of the internal connection pins. With such a configuration, the characteristic impedance of each internal connection pin can be easily set to a desired value by sandwiching an array of two or more internal connection pins between two impedance adjustment plates.

  In the probe card according to the fourth aspect of the present invention, in addition to the above configuration, the internal connection pins can be deformed in a plane parallel to the impedance adjustment plate. With such a configuration, even when the internal connection pin is deformed by being sandwiched between the main board and the contact unit, the characteristic impedance hardly changes and the variation in the characteristic impedance of the internal connection pin can be easily performed. Can be suppressed.

  The probe card according to the fifth aspect of the present invention is configured by connecting the impedance adjusting plate to a plate electrode formed on the upper surface of the contact unit, in addition to the above configuration. With such a configuration, the impedance adjustment plate can be connected to the stable potential of the contact unit, for example, the ground level.

  According to the present invention, since the impedance adjustment plate is provided so as to face the main surface of the internal connection pin that conducts the main substrate and the contact unit, the characteristic impedance of the internal connection pin is adjusted, and at both ends of the internal connection pin Reflection can be suppressed. Therefore, the high frequency characteristics of the probe card can be improved.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an example of a schematic configuration of a probe apparatus 1 including a probe card 100 according to Embodiment 1 of the present invention, and shows an internal state of the probe apparatus 1. The probe device 1 includes a probe card 100, a movable stage 3 on which an inspection object 2 is placed, a drive device 4 that moves the movable stage 3 up and down, and a housing 5 that houses the movable stage 3 and the drive device 4. Consists of.

  The inspection object 2 is a semiconductor device, for example, a semiconductor wafer on which a plurality of semiconductor integrated circuit chips (not shown) are formed, and is placed on the movable stage 3 with the electrode pad formation surface facing up. Yes. The movable stage 3 is a mounting table having a horizontal mounting surface, and is driven by the driving device 4 so as to be raised or lowered in the vertical direction with the inspection object 2 placed on the mounting surface. .

  An opening is formed in the upper part of the housing 5, and the probe card 100 is attached with the contact probe forming surface facing the lower surface so as to seal the opening. The movable stage 3 is disposed below the opening, and by raising the movable stage 3, the electrode pad on the inspection object 2 and the contact probe on the probe card 100 are brought into contact with each other to be conducted. Can do.

  2 to 4 are diagrams showing a configuration example of the probe card 100 of FIG. FIG. 2 shows a state where the probe card 100 is viewed from the inspection object 2 side. FIG. 3 shows a cross-sectional view taken along the line AA, and FIG. 4 shows a cross-sectional view taken along the line BB. This probe card 100 differs from the conventional probe card in that an impedance adjustment plate 31 is disposed between adjacent internal connection pins 30.

  The probe card 100 according to the present embodiment includes a main substrate 10, a contact unit 20, an internal connection pin 30, and an impedance adjustment plate 31. The main board 10 and the contact unit 20 are electrically connected via a large number of internal connection pins 30, and the characteristic impedance of these internal connection pins 30 is adjusted by an impedance adjustment plate 31.

  The main substrate 10 is a substrate attached to the probe apparatus 1 and includes a reinforcing plate 11, a large number of external electrodes 12, a contact unit support portion 13, and a large number of internal electrodes 15. As the main board 10, a multilayer printed board made of, for example, glass epoxy is used. The reinforcing plate 11 is a metal block for suppressing distortion of the main board 10 and is fixed to the upper surface of the main board 10. The external electrode 12 is a terminal for conducting with devices other than the probe card 100 such as a tester, and is formed in the vicinity of the peripheral portion of the main substrate 10 in order to widen the electrode pitch. The internal electrode 15 is a terminal that is formed near the center of the main substrate 10 and is electrically connected to the contact unit 20 via the internal connection pin 30.

  The contact unit support portion 13 holds the contact unit 20 so as to be movable up and down below the main substrate 10. Here, the contact unit support portion 13 is formed on the lower surface of the main substrate 10 as a wall surface (or arm portion) surrounding the contact unit 20. This wall surface extends downward from the main substrate 10 and has its tip bent toward the contact unit 20 side. The lower surface of the contact unit 20 is brought into contact with the upper surface of the bent tip portion so as to prevent the contact unit 20 from falling.

  The contact unit 20 includes a large number of contact probes 21, a contact substrate 22, a space converter 23, a large number of internal electrodes 25, and a large number of plate electrodes 26. The contact unit 20 is disposed below the main substrate 10 so as to be parallel to the main substrate 10 with the upper surface on which the internal electrode 25 is formed facing the main substrate 10.

  The contact probe 21 is made of a conductive metal having a cantilever structure, and its fixed end is fixed on the contact substrate 22, and at the time of inspection, the free end is elastically applied to the electrode pad on the inspection object 2. Make contact. The contact substrate 22 is a substrate made of a single crystal such as silicon, and a large number of contact probes 21 are arranged on the lower surface thereof in association with electrode pads on the inspection object 2. A space converter 23 is formed on the upper surface.

  The space converter 23 has a lower surface fixed to the contact substrate 22, and a large number of internal electrodes 25 and plate electrodes 26 are formed on the upper surface. In this example, the contact unit support portion 13 holds the contact unit 20 by supporting the peripheral edge portion of the space converter 23.

  Each internal electrode 25 is electrically connected to the corresponding contact probe 21 through the wiring 24 in the space converter 23 and the through hole in the contact substrate 22. Since the contact probes 21 are arranged at a narrow pitch, while the internal electrodes 25 are arranged at a wider pitch, the corresponding contact probes 21 and the internal electrodes 25 are electrically connected using the space converter 23. I am letting. That is, the space converter 23 adjusts the difference in the arrangement positions of the contact probe 21 and the internal electrode 25.

  The plate electrode 26 is an electrode to which the impedance adjustment plate 31 is connected. The plate electrode 26 is held at a stable potential level with respect to the ground level (ground potential) of the contact substrate 22. Here, it is assumed that the plate electrode 26 is electrically connected to the ground internal electrode 25 via the wiring 24 in the space converter 23 and holds the impedance adjustment plate 31 at the ground level.

  The internal connection pin 30 is made of an elastically deformable conductive metal, and conducts the internal electrodes 15 and 25 facing each other of the main substrate 10 and the contact unit 20. In consideration of productivity, it is desirable that the internal connection pin 30 is fixed to one of the internal electrodes 15 and 25 and elastically abuts on the other. In this example, one end of the internal connection pin 30 is connected to the main connection pin 30. Soldered to the internal electrode 15 of the substrate 10, the other end is in contact with the internal electrode 25 of the contact unit 20. The internal connection pin 30 has a curved shape in a plane and is configured to be elastically deformed in the plane. By deforming such an internal connection pin 30 between the main substrate 10 and the contact unit 20, the internal connection pin 30 can be brought into contact with the internal electrode 25 while being urged. For this reason, the corresponding internal electrodes 15 and 25 can be reliably conducted via the internal connection pin 30.

  The impedance adjustment plate 31 is a thin plate made of a conductive metal, and is fixed to the upper surface of the space converter 23 in a state of being electrically connected to the plate electrode 26. The impedance adjustment plate 31 is disposed so as to be parallel to the main surface 30 m of the corresponding internal connection pin 30, and forms a capacitive element with the internal connection pin 30. For this reason, if the distance from the internal connection pin 30 to the impedance adjustment plate 31 is set to a predetermined length, the characteristic impedance of the internal connection pin 30 can be adjusted to a desired value.

  The main surface 30m of the internal connection pin 30 refers to a surface having the largest area when the shape of the internal connection pin 30 is projected onto a plane. In the present embodiment, a plane (curved plane) in which each internal connection pin 30 is curved is the main surface 30m, and the impedance adjustment plate 31 is arranged to be parallel to the curved plane. For this reason, the electrostatic capacitance of the internal pin 30 can be adjusted efficiently, and even if the internal connection pin 30 is deformed, the characteristic impedance does not change significantly.

  FIG. 5 is a diagram showing a configuration example of the contact unit 20 of FIGS. 3 and 4. This figure is a diagram showing a state when the contact unit 20 is viewed from the upper surface side, and shows an upper surface of the space converter 23 in which the internal electrode 25, the plate electrode 26, and the impedance adjustment plate 31 are arranged. Yes.

  The internal electrodes 25 are arranged in a matrix on the upper surface of the space converter 23. Here, the two or more internal connection pins 30 are aligned in the row direction so that the main surfaces 30m are on the same plane, and the two or more internal connection pins 30 are arranged at a constant pitch with the main surfaces 30m facing each other. A large number of internal electrodes 25 are arranged in a matrix so as to be aligned in the column direction. Two or more plate electrodes 26 are arranged between each row of the internal electrodes 25. These plate electrodes 26 are provided for each internal connection pin 30, and an impedance adjustment plate 31 is fixed to each plate electrode 26 by soldering or the like. That is, the internal connection pins 30 and the impedance adjustment plate 31 are arranged in a one-to-one correspondence.

  FIG. 6 is a diagram showing another configuration example of the contact unit 20 of FIGS. 3 and 4, and shows a state when the contact unit 20 is viewed from the upper surface side, as in FIG. 5. In this contact unit 20, one impedance adjustment plate 31 is associated with two or more internal connection pins 30, and the distance from each internal connection pin 30 to the impedance adjustment plate 31 is a fixed length.

  One plate electrode 26 is arranged between each row of the internal electrodes 25. These plate electrodes 26 have an elongated shape extending in the row direction, and an elongated impedance adjusting plate 31 extending in the row direction is fixed on each plate electrode 26 by soldering or the like. That is, one impedance adjustment plate 31 is associated with all the internal electrodes 25 arranged in the row direction.

In general, if the inductance per unit length is L and the capacitance is C, the characteristic impedance can be represented by (L / C) ^1/2 . For this reason, if the shape of each internal connection pin 30 is the same, these characteristic impedances are also constant. Therefore, if the impedance adjustment plate 31 is provided and the distance from the internal connection pin 30 to the impedance adjustment plate 31 and the shape of the internal connection pin 30 are appropriately designed, the characteristic impedance of each internal connection pin 30 is set to a desired value. Can be.

  If the characteristic impedance of the signal input / output terminal of the tester is 50Ω, the main substrate 10 and the contact unit 20 are also designed to have a characteristic impedance of 50Ω, and the impedance of each signal propagation path is matched. In addition, if the impedance adjustment plate 31 is used, the characteristic impedance of each internal connection pin 30 can be designed to be 50Ω, and reflection of high frequency signals at both ends of each internal connection pin 30 can be suppressed. become able to. That is, by providing the impedance adjustment plate 31, the loss in the probe card 100 can be remarkably reduced and the high frequency characteristics can be remarkably improved.

  According to the present embodiment, in the probe card 100 that conducts the internal electrode 15 on the main substrate 10 and the internal electrode 25 on the contact unit 20 facing the internal electrode 15 using a large number of internal connection pins 30. By arranging the impedance adjustment plate 31 facing the main surface 30m of the internal connection pin 30 in the vicinity of the internal connection pin 30, the characteristic impedance of each internal connection pin 30 can be set to a desired value. The reflection of the high frequency signal at both ends of the pin 30 can be suppressed. In addition, the characteristic impedance can be prevented from changing depending on the deformation state of the internal connection pin 30.

  Further, in the present embodiment, two or more internal connection pins 30 that are elastically deformed in a plane are arranged on a straight line so that the planes coincide with each other, and the impedance adjustment plate is parallel to the plane. Is arranged. For this reason, the characteristic impedance of each of the two or more internal connection pins 30 can be adjusted by the same impedance adjustment plate 31.

  In the present embodiment, the internal connection pin 30 is fixed to the internal electrode 25 on the main substrate 10, and the impedance adjustment plate 31 is fixed to the internal electrode 15 on the contact unit 20. The main connection pin 30 and the contact unit 20 are arranged to face each other using the contact unit support portion 13, so that the internal connection pins 30 are in elastic contact with the contact unit 20. For this reason, the probe card according to the present invention can be easily manufactured as compared with the case where both the internal connection pin 30 and the impedance adjustment plate 31 are fixed to the contact unit 20.

Embodiment 2. FIG.
In Embodiment 1, the example in the case of arrange | positioning the internal connection pin 30 and the impedance adjustment plate 31 alternately was demonstrated. On the other hand, in the second embodiment, a case where two impedance adjustment plates 31 are arranged between the rows of the internal connection pins 30 will be described.

  FIG. 7 is a view showing a state when the contact unit 20 according to the second embodiment of the present invention is viewed from the upper surface side. The space conversion in which the internal electrode 25, the plate electrode 26, and the impedance adjustment plate 31 are arranged is shown. The top surface of the vessel 23 is shown. Compared to FIG. 6 (Embodiment 1), in the contact unit 20 according to Embodiment 2, two plate electrodes 26 are formed between adjacent internal electrodes 25, and each plate electrode 26 has an impedance adjustment plate. The difference is that 31 is arranged.

  As in the case of FIG. 6, the internal electrodes 25 are arranged in a matrix on the upper surface of the space converter 23. That is, the internal connection pins 30 whose main surfaces 30m are on the same plane are aligned in the row direction at a constant pitch, and the internal connection pins 30 that face each other's main surfaces 30m are aligned in the column direction at a constant pitch. As described above, the internal electrode 25 is arranged.

  FIG. 8 is an explanatory diagram of a method for obtaining the distance between the internal connection pin 30 and the impedance adjustment plate 31 using a theoretical formula. In the drawing, a plurality of internal connection pins 30 each having a rectangular shape with a width W and a thickness t are arranged at a pitch P so that the main surfaces 30m are on the same plane. These internal connection pins 30 are sandwiched between two parallel impedance adjustment plates 31 and are disposed at positions that are equidistant from each impedance adjustment plate 31.

If the internal connection pin 30 is regarded as a strip line and a theoretical formula of the strip line is applied, a relational expression between the distance H between the internal connection pin 30 and the impedance adjustment plate 31 and the characteristic impedance Zo of the internal connection pin 30 can be obtained. it can. If the relative dielectric constant of the medium between the internal connection pin 30 and the impedance adjustment plate 31 is ε, the distance H between the internal connection pin 30 and the impedance adjustment plate 31 is expressed by the following equation.

  For example, if the desired characteristic impedance Zo is 50Ω, the width W of the internal connection pin 30 is 100 μm, and the thickness t is 8 μm, along with the relative permittivity of air 1.0 and substituting these values into the above formula, About 200 μm can be obtained as the distance H between the connection pin 30 and the impedance adjustment plate 31. That is, if the distance H is about 200 μm, the characteristic impedance of the internal connection pin 30 can be 50Ω. In addition, the inter-row pitch of the internal electrodes 25 is normally secured to 1 mm or more.

  In order to set the characteristic impedance Zo of the internal connection pin 30 to a desired value, it is necessary to make the distance H between the internal connection pin 30 and the impedance adjustment plate 31 coincide with the length h corresponding to the desired characteristic impedance Zo. is there. If the pitch between the rows of the internal connection pins 30 is larger than 2h, H = h can be obtained by arranging two impedance adjustment plates 31 between the adjacent internal connection pins 30. Since the capacitance of the internal connection pin 30 is determined by the distance to the adjacent impedance adjustment plate 31, two impedance adjustment plates 31 are arranged between the internal connection pins 30 when the pitch of the internal connection pins 30 is wide. For example, the characteristic impedance Zo of the internal connection pin 30 can be set to a desired value regardless of the pitch. Needless to say, when the pitch between the rows of the internal connection pins 30 is equal to 2h, one impedance adjustment plate 31 may be arranged at the center between the rows of the internal connection pins 30.

  In the above embodiment, the configuration example in which the internal connection pin 30 is fixed to the internal electrode 15 of the main substrate 10 and the impedance adjustment plate 31 is fixed to the plate electrode 26 of the contact unit 20 has been described. The probe card according to the invention is not limited to such a configuration. For example, the internal connection pin 30 may be fixed to the internal electrode 25 of the contact unit 20, and the impedance adjustment plate 31 may be fixed to a plate electrode (not shown) formed on the lower surface of the main substrate 10. . Further, the internal connection pin 30 and the impedance adjustment plate 31 may be both fixed to the main substrate 10 or may be fixed to the contact unit 20 together.

It is the figure which showed an example of schematic structure of the probe apparatus 1 containing the probe card 100 by Embodiment 1 of this invention. The state when the probe card 100 of FIG. 1 is viewed from the inspection object 2 side is shown. A cross-sectional view when the probe card of FIG. 2 is cut along an AA cutting line is shown. A cross-sectional view of the probe card of FIG. 2 taken along the line BB is shown. It is the figure which showed the mode at the time of seeing an example of the contact unit 20 of FIG.3 and FIG.4 from the upper surface side. It is the figure which showed the mode at the time of seeing the other example of the contact unit 20 of FIG.3 and FIG.4 from the upper surface side. It is the figure which showed the mode at the time of seeing the contact unit 20 by Embodiment 2 of this invention from the upper surface side. It is explanatory drawing of the method of calculating | requiring the distance H between the internal connection pin 30 and the impedance adjustment plate 31 using a theoretical formula.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probe apparatus 2 Inspection object 10 Main board 12 External electrode 13 Contact unit support parts 15 and 25 Internal electrode 20 Contact unit 21 Contact probe 22 Contact board 26 Plate electrode 30 Internal connection pin 30m Main surface 31 of internal connection pin Impedance adjustment Plate 100 Probe card H Distance between internal connection pin and impedance adjustment plate P Internal connection pin pitch W Internal connection pin width t Internal connection pin thickness Zo Characteristic impedance of internal connection pin

Claims (5)

A main substrate having two or more first electrodes formed on the lower surface;
A contact unit in which two or more second electrodes are formed on the upper surface facing the first electrode, and two or more contact probes respectively connected to the second electrode are formed on the lower surface;
Two or more internal connection pins disposed between the main substrate and the contact unit and conducting the first electrode and the second electrode;
A probe card, comprising: an impedance adjustment plate arranged to face the main surface of the internal connection pin.   2. The probe card according to claim 1, wherein two or more internal connection pins are arranged on a straight line, and each main surface of the internal connection pins is opposed to one impedance adjustment plate.   The probe card according to claim 2, wherein the impedance adjustment plates parallel to each other are arranged so as to sandwich the array of the internal connection pins.   The probe card according to claim 1, wherein the internal connection pin is deformable in a plane parallel to the impedance adjustment plate.   The probe card according to claim 1, wherein the impedance adjustment plate is connected to a plate electrode formed on an upper surface of the contact unit.

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