JP7697905B2 - Wiring board and probe card - Google Patents

Description

This disclosure relates to wiring boards and probe cards.

Patent document 1 describes a wiring substrate for a probe card.

JP 2010-177555 A

A wiring board for a probe card has multiple probe pins bonded to its underside and multiple wiring conductors on its top side. Multiple contact conductors contact the multiple wiring conductors on the top side, respectively, and the wiring board is electrically connected to a circuit board separate from the wiring board via the contact conductors. It is desirable for the wiring board to have good contact with the contact conductors (contact that provides good conductivity with moderate pressure).

The present disclosure aims to provide a wiring board and a probe card that can achieve good contact with the contact conductor.

The wiring board according to the present disclosure includes:
an insulating substrate having a first surface and a second surface opposite to the first surface;
a plurality of wiring conductors located on the first surface and the second surface;
Equipped with
When the first surface is divided into two regions, a circular first region located at the center of the first surface, and a second region surrounding the first region and having the same area as the first region,
the plurality of wiring conductors include a plurality of first wiring conductors located in the first region and a plurality of second wiring conductors located in the second region;
The thickness of the second wiring conductors is greater than the thickness of the first wiring conductors.

The probe card according to the present disclosure comprises:
The above wiring board;
a plurality of probe pins electrically connected to a plurality of wiring conductors located on the second surface;
Equipped with.

Another aspect of the present disclosure provides a probe card comprising:
one or more bonding metal films located on the first surface;
the wiring substrate in which more than half of the total number of the bonding metal films are located in the first region;
a plurality of probe pins electrically connected to a plurality of wiring conductors located on the second surface;
A metal member bonded to the bonding metal film;
Equipped with.

This disclosure provides a wiring board and a probe card that can achieve good connectivity with the connecting conductor.

FIG. 2 is a plan view showing a wiring conductor according to the first embodiment of the present disclosure. 1A is a longitudinal sectional view showing a wiring conductor of embodiment 1, and FIG. 1B is a partially enlarged view showing the same. 1 is a vertical cross-sectional view showing a probe card according to a first embodiment of the present disclosure. FIG. 11 is a plan view showing a wiring conductor according to a second embodiment of the present disclosure. FIG. 11 is a longitudinal sectional view showing a probe card according to a second embodiment of the present disclosure.

Each embodiment of the present disclosure will be described in detail below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view showing a wiring conductor according to the first embodiment of the present disclosure. FIG. 2 is a longitudinal cross-sectional view (A) showing the wiring conductor according to the first embodiment, and partial enlarged views (B) and (C). FIG. 3 is a longitudinal cross-sectional view showing a probe card according to the first embodiment of the present disclosure. FIG. 2(A) and FIG. 3 show schematic diagrams in which the number of wiring conductors 12, 13, and 14 has been reduced, and the like has been simplified in terms of drawing. In FIG. 2(A) and FIG. 3, the aspect ratio of each component, the amount of warping of the insulating substrate 11, the thickness of the wiring conductors 12 and 13, the inclination angle of the wiring conductor 12 relative to the first surface S1, and the like are exaggerated. Hereinafter, the first surface S1 side of the wiring board 10 will be described as the upper side, and the second surface S2 side as the lower side. FIG. 1 shows the first surface S1 side of the wiring board 10.

The wiring board 10 of the first embodiment may be a wiring board 10 for a probe card. The wiring board 10 includes an insulating substrate 11 having a first surface S1 and a second surface S2 located on the opposite side of the first surface S1, a plurality of wiring conductors 12 located on the first surface S1, a plurality of wiring conductors 13 located on the second surface S2, and a wiring conductor 14 located inside the insulating substrate 11.

The material of the insulating substrate 11 may be mullite ceramic or other ceramics. The wiring substrate 10 and the insulating substrate 11 may be a regular polygon having eight or more corners or a circle in a plan view. By using such a shape, stress can be dispersed at the edge of the insulating substrate 11, and thus the strength of the wiring substrate 10 can be improved. The wiring substrate 10 and the insulating substrate 11 may have a size corresponding to the wafer (silicon wafer, etc.) that is the object of inspection by the probe card 1. When the wiring substrate 10 is used as the probe card 1, the first surface S1 of the wiring substrate 10 may be a surface facing the circuit substrate 20 (FIG. 3) connected to the inspection device. The second surface S2 of the wiring substrate 10 may be a surface facing the object of inspection (silicon wafer, etc.).

The wiring conductors 12, 13, and 14 (FIG. 2(A)) may be conductors that exchange (send and receive) signals or power supply voltages between the first surface S1 and the second surface S2.

The multiple wiring conductors 12 on the first surface S1 may be conductors electrically connected to the circuit board 20 via contact conductors 31 (FIG. 3). The multiple wiring conductors 12 may be electrode pads. The contact conductors 31 may have a spring effect and be configured to contact the wiring conductors 12 using the repulsive force of the spring to establish electrical continuity with the wiring conductors 12. The wiring conductors 12 may be conductors formed by forming a thin film of a pattern corresponding to the wiring conductors 12 on the first surface S1 by a thin film formation process such as a sputtering process, and then plating the thin film by an electrolytic plating process.

The multiple wiring conductors 13 on the second surface S2 may be conductors to which probe pins 41 (FIG. 3) are joined. The multiple wiring conductors 13 may be electrode pads. The wiring conductors 13 may be conductors formed by forming a thin film of a pattern corresponding to the wiring conductors 13 on the second surface S2 by a thin film formation process such as a sputtering process, and then plating the thin film by an electrolytic plating process.

The wiring conductor 14 may be a conductor that electrically connects the wiring conductor 12 on the first surface S1 and the wiring conductor 13 on the second surface S2. The insulating substrate 11 has a laminated structure in which multiple insulating layers are stacked, and the wiring conductor 14 may include a film-like or linear metallized conductor located between the multiple insulating layers and a via conductor extending between the insulating layers.

<Details of the Wiring Conductor 12 on the First Surface S1 and the Wiring Conductor 13 on the Second Surface S2>
In the following, the first surface S1 will be described by dividing it into two regions: a circular first region R1 located at the center of the first surface S1, and a second region R2 surrounding the first region R1 and having an area equal to that of the first region R1. In FIG. 1, the boundary between the first region R1 and the second region R2 is indicated by a dashed line. The center point of the first region R1 may overlap with the center point of the first surface S1. In the following, the wiring conductor 12 located in the first region R1 will be referred to as the "first wiring conductor 12a", the wiring conductor 12 located in the second region R2 will be referred to as the "second wiring conductor 12b", and the wiring conductor 13 located on the second surface S2 will be referred to as the "third wiring conductor 13".

As shown in FIG. 2A, the thickness of the second wiring conductors 12b is greater than the thickness of the first wiring conductors 12a. The thickness T1aa (FIG. 2B) of each of the first wiring conductors 12a may not be constant. Similarly, the thickness T2aa (FIG. 2C) of each of the second wiring conductors 12b may not be constant. The thickness of the first wiring conductors 12a may be the average thickness of all the first wiring conductors 12a, the median thickness, the average thickness after removing the thickest 3% of the first wiring conductors 12a and the thinnest 3% of the first wiring conductors 12a to remove extreme thicknesses, the maximum thickness, or the minimum thickness. Similarly, the thickness of the multiple second wiring conductors 12b may be the average thickness of all the second wiring conductors 12b, the median thickness, the average thickness, the maximum thickness, or the minimum thickness after removing the thickest 3% of the second wiring conductors 12b and the thinnest 3% of the second wiring conductors 12b to eliminate extreme differences. When comparing thicknesses, the same definition may be applied to the thickness of the first wiring conductor 12a and the thickness of the second wiring conductor 12b.

The thickness of the first wiring conductor 12a and the thickness of the second wiring conductor 12b may be controlled by applying electrolytic plating as the plating process for forming the wiring conductors 12 and adjusting the current passed through the pattern of the first wiring conductor 12a and the current passed through the pattern of the second wiring conductor 12b during electrolytic plating.

According to the above configuration, when the multiple wiring conductors 12 and the multiple contact conductors 31 (FIG. 3) are electrically connected, the distance between the surface of the first wiring conductor 12a in the first region R1 and the contact conductor 31 becomes relatively large. On the other hand, the distance between the surface of the second wiring conductor 12b in the second region R2 and the contact conductor 31 becomes relatively small. Therefore, the pressure applied from the contact conductor 31 to the first wiring conductor 12a can be reduced, and the pressure applied from the contact conductor 31 to the second wiring conductor 12b in the second region R2 can be increased. Therefore, the contact between the second wiring conductor 12b and the contact conductor 31 is improved. Furthermore, the wiring conductors 12 tend to gather more in the first region R1 on the first surface S1. Therefore, if the pressure applied from each contact conductor 31 to each first wiring conductor 12a is large, the total pressure applied to the first region R1 becomes excessive, and the stress generated in the wiring conductor 12 increases. However, according to the above configuration of the first embodiment, the overall pressure applied to the first region R1 is reduced, so that the stress generated in the wiring board 10 can be reduced. Therefore, good contact between the wiring conductor 12 and the contact conductor 31 can be obtained in both the first region R1 and the second region R2.

The wiring conductors 12 (first wiring conductor 12a and second wiring conductor 12b) on the first surface S1 may be configured so that their thickness gradually decreases toward the center. With this configuration, the pressure applied from the contact conductors 31 to the wiring conductors 12 can be increased toward the edge of the first surface S1, and the contact between the wiring conductors 12 located near the edge of the first surface S1 and the contact conductors 31 can be further improved. Furthermore, the total pressure applied from the multiple contact conductors 31 to the center of the first surface S1 is reduced, and the stress generated in the wiring board 10 can be reduced. Therefore, the contact between the wiring conductors 12 and the contact conductors 31 in the center can be improved.

In a plan view, the total area of the multiple first wiring conductors 12a may be greater than the total area of the multiple second wiring conductors 12b. In this configuration, if the thickness of the first wiring conductor 12a and the thickness of the second wiring conductor 12b are the same, the total pressure applied from the contact conductor 31 to the first region R1 is greater than the total pressure applied from the contact conductor 31 to the second region R2. Therefore, in this configuration, by making the thickness of the first wiring conductor 12a smaller than the thickness of the second wiring conductor 12b, the total pressure in the first region R1 is reduced, and good contact is obtained in the first region R1.

When multiple types of wiring boards 10 with different patterns are prepared, the difference between the thickness (average thickness) of the multiple first wiring conductors 12a and the thickness (average thickness) of the multiple second wiring conductors 12b may be set to be greater as the difference between the total area of the multiple first wiring conductors 12a and the total area of the multiple second wiring conductors 12b increases. With this configuration, the total pressure applied from the contact conductors 31 to the first region R1 can be made to be of a good magnitude in any of the multiple types of wiring boards 10, thereby improving the contact in the first region R1.

In a plan view, the total area of the multiple first wiring conductors 12a and the multiple second wiring conductors 12b may be larger than the total area of the multiple third wiring conductors 13. In this configuration, the difference in the expansion coefficient between the conductor and the insulating substrate 11 tends to cause warping that makes the first surface S1 convex. This warping acts to increase the total pressure applied to the first region R1 from the contact conductor 31. Therefore, the effect based on the fact that the thickness of the first wiring conductor 12a is smaller than the thickness of the second wiring conductor 12b (the effect of reducing the total pressure in the first region R1) functions effectively, and the contact in the first region R1 can be improved.

In a plan view, the total area of the multiple first wiring conductors 12a may be 55% or more and 76% or less of the total area of the multiple wiring conductors 12 (first wiring conductor 12a, second wiring conductor 12b) located on the first surface S1. This configuration makes it easy to provide an appropriate thickness difference between the first wiring conductor 12a and the second wiring conductor 12b, and this thickness difference can improve the contact between the contact conductor 31 and the first wiring conductor 12a and the second wiring conductor 12b.

The following relationship table 1 shows an example of the relationship between the conductor area ratio (the ratio of the total area of the multiple first wiring conductors 12a located in the first region R1 to the total area of the multiple wiring conductors 12 located on the first surface S1) and the thickness of the first wiring conductor 12a, the thickness of the second wiring conductor 12b, and the difference in thickness that provides good contact.

<Relationship Table 1>

(Probe card)
3, the probe card 1 according to the first embodiment of the present disclosure includes the above-described wiring substrate 10 and a plurality of probe pins 41 respectively joined to a plurality of wiring conductors 13 on the second surface S2. The probe pins 41 may be joined to the wiring conductors 13 via a joining material such as solder.

The probe card 1 may further include a circuit board 20 connected to an inspection device (not shown), a frame 22 supporting the wiring board 10, and a plurality of contact conductors 31 interposed between the circuit board 20 and the wiring board 10. The frame 22 may be configured to support the edge of the wiring board 10 from below. The frame 22 may be fixed to the circuit board 20, and the wiring board 10 and the circuit board 20 may be integrated. The plurality of contact conductors 31 may contact a plurality of electrode pads 21 located on the lower surface of the circuit board 20 and a plurality of wiring conductors 12 of the wiring board 10, thereby electrically connecting the corresponding electrode pads 21 and wiring conductors 12.

The multiple contact conductors 31 may be integrated with each other by having their central portions supported by an insulating plate or sheet (not shown). The integrated multiple contact conductors 31 may be called an interposer.

According to the probe card 1 having this configuration, the probe pins 41 of the probe card 1 are connected to electrodes on the silicon wafer to be inspected. Then, an inspection device (not shown) connected to the circuit board 20 can inspect the inspection object by exchanging signals and/or power supply voltage with the inspection object via the circuit board 20, the multiple contact conductors 31, the wiring board 10, and the probe pins 41.

The probe card 1 of embodiment 1 achieves good contact between the wiring board 10 and the contact conductor 31, allowing good exchange of signals and/or power supply voltage between the inspection device and the subject to be inspected.

(Embodiment 2)
Fig. 4 is a plan view showing a wiring conductor according to the second embodiment of the present disclosure. Fig. 5 is a vertical cross-sectional view showing a probe card according to the second embodiment of the present disclosure. Fig. 5 shows a schematic diagram that has been simplified in terms of drawing.

The wiring board 10A and probe card 1A of embodiment 2 differ in that another element is added to the configuration in which the circuit board 20A supports the wiring board 10A, but the other components may be the same as those of embodiment 1.

The wiring board 10A of the second embodiment may further include a bonding metal film 16 for bonding a supporting metal member 24, as shown in FIG. 4, in addition to the same components as those of the first embodiment. The bonding metal film 16 may be located on the first surface S1. The wiring board 10A may include multiple bonding metal films 16, or may include only one bonding metal film 16. The bonding metal film 16 may have an area larger than each of the wiring conductors 12, 13 in a plan view. The bonding metal film 16 may be polygonal, circular, or elongated in one direction in a plan view.

The bonding metal film 16 may be a conductor formed by forming a thin film having a pattern corresponding to the bonding metal film 16 on the first surface S1 by a thin film formation process such as a sputtering process, and then plating the thin film by an electrolytic plating process.

In the probe card 1A, the metal member 24 is bonded to the bonding metal film 16, and the metal member 24 supports the wiring board 10A from above (see FIG. 5). That is, the metal member 24 exerts a force in a direction that lifts the bonding metal film 16. This force counteracts the force of the multiple contact conductors 31 in the direction that presses the wiring board 10A, and acts to counteract the distortion of the wiring board 10A caused by the pressure of the multiple contact conductors 31.

The bonding metal film 16 may be entirely located in the first region R1 as shown in FIG. 4, or more than half of the total area may be located in the first region R1. With this configuration, most of the bonding metal film 16 is included in the first region R1 where the pressure of the multiple contact conductors 31 is large, so that the first region R1 acts against the distortion of the bonding metal film 16, and the stress of the wiring board 10A in the first region R1 can be alleviated. Furthermore, around the bonding metal film 16, the force of the bonding metal film 16 lifting the wiring board 10A and the force of the multiple contact conductors 31 pressing down on the wiring board 10A cancel each other out. Therefore, the concentration of stress around the bonding metal film 16 can be alleviated.

The probe card 1A of the second embodiment may further include a metal member 24 (e.g., a bolt and a nut) and a support portion (through hole, etc.) 26 located on the circuit board 20A, in addition to the same components as those of the first embodiment. The metal member 24 may be joined to the joining metal film 16 via a joining member 8 such as a brazing material. Then, another portion of the metal member 24 may engage with the support portion 26 of the circuit board 20A, so that the circuit board 20A supports the wiring board 10A via the metal member 24.

The wiring board 10A of the second embodiment realizes good contact between the multiple wiring conductors 12 on the first surface S1 and the contact conductor 31, and can relieve stress on the wiring conductors 12. The probe card 1A of the second embodiment realizes good exchange of signals and/or power supply voltage between the inspection device and the inspection target by the wiring board 10A that provides the above-mentioned effects.

Each embodiment of the present disclosure has been described above. However, the wiring board and probe card of the present disclosure are not limited to the above-described embodiments. The details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

REFERENCE SIGNS LIST 1, 1A Probe card 8 Bonding member 10, 10A Wiring board 11 Insulating board 12, 14 Wiring conductor 12a First wiring conductor 12b Second wiring conductor 13 Wiring conductor (third wiring conductor)
16 Bonding metal film R1 First region R2 Second region T1aa, T2aa Thickness 20, 20A Circuit board 21 Electrode pad 22 Frame 24 Metal member 26 Support portion 31 Contact conductor 41 Probe pin

Claims (8)

an insulating substrate having a first surface and a second surface opposite to the first surface;
a plurality of wiring conductors located on the first surface and the second surface;
Equipped with
When the first surface is divided into two regions, a circular first region located at the center of the first surface, and a second region surrounding the first region and having the same area as the first region,
the plurality of wiring conductors include a plurality of first wiring conductors located in the first region and a plurality of second wiring conductors located in the second region;
The thickness of the second wiring conductors is greater than the thickness of the first wiring conductors.
Wiring board. a total area of the plurality of first wiring conductors is larger than a total area of the plurality of second wiring conductors in a plan view;
The wiring board according to claim 1. the plurality of wiring conductors include a plurality of third wiring conductors located on the second surface,
a total area of the plurality of first wiring conductors and the plurality of second wiring conductors is larger than a total area of the plurality of third wiring conductors in a plan view;
The wiring board according to claim 1 or 2. a total area of the plurality of first wiring conductors is 55% or more and 76% or less of a total area of the plurality of wiring conductors located on the first surface in a plan view;
The wiring board according to claim 1 . The insulating substrate has a regular polygonal shape having eight or more corners or a circular shape in a plan view.
The wiring board according to claim 1 . one or more bonding metal films located on the first surface;
In a plan view, half or more of a total area of the bonding metal film is located in the first region.
The wiring board according to claim 1 . The wiring board according to any one of claims 1 to 6,
a plurality of probe pins electrically connected to a plurality of wiring conductors located on the second surface;
A probe card comprising: The wiring board according to claim 6 ;
a plurality of probe pins electrically connected to a plurality of wiring conductors located on the second surface;
A metal member bonded to the bonding metal film;
A probe card comprising:

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