JP2009074958A - Probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe card capable of narrowing a mounting pitch when a number of contact probes are disposed on a probe substrate. <P>SOLUTION: The probe card 10 comprises a probe substrate 12 and a plurality of planar contact probes 11 that are bonded to the probe substrate 12 with confronting their edge faces, in which the plurality of contact probes 11 are constituted by laminating conductive layers 21 to 23, and the edge faces are concavo-convex, and positions of layers projecting at the their edge faces are be the same. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a probe card, and more particularly, to an improvement in a probe card including a plurality of contact probes that are flat and have end faces butted on a probe substrate.

  In general, in the manufacturing process of a semiconductor device, an electrical characteristic test is performed on an electronic circuit formed on a semiconductor wafer. A probe card is used for the electrical characteristic test for such an inspection object. A probe card is a device in which a large number of contact probes are arranged on a probe substrate, and each contact probe is brought into contact with a large number of electrode pads on an object to be inspected to electrically connect the contact probes and the electrode pads. Characteristic testing is performed. The contact probe is formed, for example, by laminating a plurality of conductive layers, and includes a beam portion that forms a cantilever structure and a bonding portion that is bonded onto the probe substrate.

  FIG. 9 is a view showing a conventional contact probe, and shows a contact probe 100 formed by laminating conductive layers. The contact probe 100 is composed of three conductive layers 101 to 103, and a contact portion 131 formed by the end face 111 of each conductive layer and a contact portion 131 for contacting an electrode pad on the inspection object are provided at the tip portion. And the formed beam portion 120. The contact portion 131 is formed by projecting the central conductive layer 102 from the outer conductive layers 101 and 103 toward the inspection object. The contact probe 100 is fixed to the probe substrate via the joint 110. That is, the probe card is formed by mounting each contact probe 100 upright on the probe substrate so that the conductive layers 101 to 103 intersect the probe substrate.

  In recent years, by increasing the density of the terminal electrodes on the inspection object, it is desired to further reduce the mounting pitch when arranging the contact probes 100 on the probe substrate in a direction intersecting the extending direction of the beam portion 120. There is a request. Generally, in order to reduce the mounting pitch of contact probes, it is necessary not only to reduce the gap between contact probes, but also to miniaturize the contact probes themselves. However, when the contact probe is miniaturized, the electrical resistance of the probe itself increases. In addition, since the contact surface with the probe substrate is small, there is a problem that the resistance of the contact portion is also increased.

  Further, in the contact probe 100 described above, the end face 111 of each conductive layer to be bonded to the probe substrate cannot be perfectly matched due to a manufacturing process reason such as a limited positioning accuracy of the patterning mask. Variations always occur on the bonding surface to be bonded to the substrate. Due to the variation in the joint surface, the contact probe 100 fixed on the probe substrate is erected obliquely, and there is a possibility that the adjacent contact probe 100 contacts and short-circuits. For this reason, the conventional probe card has a problem that the mounting pitch of the contact probes 100 cannot be reduced.

  FIG. 10 is a view showing a conventional probe card, and shows a plurality of contact probes 100 in which joints 110 are soldered to electrode pads 210 on a probe substrate 200. In this probe card, each contact probe 100 is fixed by joining the joint portions 110 to the electrode pads 210 provided on the probe substrate 200 at regular intervals using solder 220. Each contact probe 100 is arranged on the probe substrate 200 so that the conductive layers 101 to 103 intersect the probe substrate 200 and the conductive layers of adjacent contact probes are opposed to each other. Due to variations in the joint surfaces of the contact probes 100, the contact probes 100 are tilted in the arrangement direction, and adjacent contact probes 100 are in contact with each other.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a probe card capable of narrowing a mounting pitch when a large number of contact probes are arranged on a probe substrate. It is another object of the present invention to provide a probe card that can suppress an increase in resistance of a contact portion of each contact probe with the probe substrate.

  A probe card according to a first aspect of the present invention is a probe card comprising a probe substrate and a plurality of contact probes that are flat and end-faced on the probe substrate, and the plurality of contact probes are: A plurality of conductive layers are stacked, the end face is uneven, and the positions of the layers protruding from the end face are the same.

  According to such a configuration, since the uneven state of the joint surface to be joined to the probe substrate is uniform for each contact probe, the direction in which the contact probes are tilted can be matched between the contact probes. Moreover, since the projections and depressions are formed on the end surface by projecting the conductive layer, the contact surface with the probe substrate can be widened, and an increase in resistance at the contact portion can be suppressed.

  In the probe card according to the second aspect of the present invention, in addition to the above configuration, the contact probe has a contact portion formed by projecting a part of the conductive layer from the other conductive layer toward the inspection object. And the conductive layer forming the contact portion is configured to form a layer that protrudes most in the end face. According to such a configuration, since the conductive layer forming the contact portion forms the most protruding layer in the end face, the height of the contact portion with respect to the probe substrate can be stabilized.

  In the probe card according to the third aspect of the present invention, in addition to the above-described configuration, the contact probe is formed by laminating three conductive layers, and the central layer forms the most protruding layer in the end face. Configured as follows. According to such a configuration, compared to the case where the layers other than the central layer are protruded, the balance with respect to the arrangement direction of the contact probes is improved, so that the contact probes can be prevented from falling down.

  According to the probe card of the present invention, the uneven state of the joint surface to be joined to the probe substrate is uniform for each contact probe, so that the direction in which the contact probes are tilted can be matched between the contact probes. Therefore, it is possible to reduce the mounting pitch when a large number of contact probes are arranged on the probe substrate. Moreover, since the projections and depressions are formed on the end surface by projecting the conductive layer, the contact surface with the probe substrate can be widened, and an increase in resistance at the contact portion can be suppressed.

Embodiment 1 FIG.
<Probe card>
FIGS. 1A and 1B are views showing an example of a probe card 10 according to Embodiment 1 of the present invention, and FIG. 1A is a plan view seen from the inspection object side. (B) in a figure is a side view. The probe card 10 includes a probe substrate 12 made of glass epoxy or the like and a plurality of contact probes 11 fixed on the probe substrate 12.

  Each contact probe 11 is provided on one main surface of the probe substrate 12. When the inspection object is a semiconductor device made of a silicon substrate, the contact probe 11 is also formed on a contact substrate (not shown) made of silicon supported by the probe substrate 12, and the thermal expansion coefficients of the two are matched. It is desirable to keep it. Each of the probe substrate 12 and the contact substrate is a wiring substrate on which a wiring pattern or the like is formed.

  In this probe card 10, contact probes 11 are arranged on a straight line at a predetermined pitch, and such rows of contact probes 11 are formed in two rows with the beam tips facing each other. Usually, the probe card 10 is held horizontally and is arranged with the main surface of the probe substrate 12 on which the contact probes 11 are formed facing downward in the vertical direction. Therefore, the inspection object is disposed below the probe card 10 so as to face the main surface of the probe substrate 12.

  When performing an electrical property test of an inspection object, the alignment of the inspection object and the probe card 10 so that each contact probe 11 faces the electrode pad on the inspection object, that is, a probe for the inspection object. The alignment of the substrate 12 is performed. With the inspection object and the probe card 10 properly aligned, the tip of the contact probe 11 can be brought into contact with the electrode pad on the inspection object by bringing the probe substrate 12 and the inspection object closer to each other. it can.

  The probe substrate 12 has a circular shape, and a large number of external terminals 13 for inputting and outputting signals to and from the tester device are formed at the peripheral edge. The peripheral portion of the probe substrate 12 is held by the housing of the probe device and supported so as to be horizontal in the housing.

  The contact probe 11 is a probe (probe) that is elastically brought into contact with a fine electrode pad formed on an object to be inspected. A large number of contact probes 11 are arranged and arranged on the probe substrate 12. Yes. Each contact probe 11 is electrically connected to the external terminal 13 via each wiring of the probe substrate 12, and by bringing the contact probe 11 into contact with each other, a minute electrode pad can be electrically connected to the tester device.

  In this embodiment, an example in which the external terminal 13 and the contact probe 11 are provided on the same substrate has been described. However, the external terminal 13 and the contact probe 11 are provided on two substrates made of different materials, respectively. A substrate in which the external terminal 13 and the wiring are formed in the portion and a substrate in which the contact probe 11 is bonded in the central portion may be bonded.

<Contact probe>
FIG. 2 is a diagram showing a configuration example of a main part of the probe card 10 of FIG. 1, and shows a contact probe 11 formed on the probe substrate 12. The contact probe 11 is formed by laminating three conductive layers 21 to 23, and is brought into contact with the joint 1 formed by the end faces 21a to 23a of the respective conductive layers 21 to 23 and the electrode pads on the inspection object. The contact part 4 for this has the beam part 2 formed in the front-end | tip part.

  The contact portion 4 is formed by projecting the central conductive layer 22 beyond the outer conductive layers 21 and 23 toward the inspection object. That is, the contact portion 4 is a structure that protrudes from the end face 3 a of the conductive layers 21 and 23.

  A low melting point layer 20 that is easily melted by heating is formed on the end faces 21a to 23a. The low melting point layer 20 is a solder bump for fixing the bonding portion 1 to the electrode pad on the probe substrate 12, and is bonded as a plating layer made of a conductive material such as solder having a lower melting point than the conductive layers 21 to 23. It is formed on the entire surface. The contact probe 11 is attached to the probe substrate 12 via the joint 1 by heating and melting the low melting point layer 20.

  The joint portion 1 is formed by projecting an end surface formed by any one of the conductive layers 21 to 23 constituting the contact probe 11 from the end surfaces of the other conductive layers. In the probe card 10 according to the present embodiment, such contact probes 11 are arranged on the probe substrate 12, thereby forming an end surface that protrudes most toward the probe substrate 12 with respect to the layer arrangement of the conductive layers 21 to 23. The positions of the conductive layers in the layer arrangement are matched with each contact probe 11.

  In this example, the end face 21 a of the outer conductive layer 21 is protruded from the end faces 22 a and 23 a of the other conductive layers 22 and 23. Here, the amount of protrusion when the end face 21a of the conductive layer 21 protrudes from the end faces 22a and 23a of the other conductive layers 22 and 23 varies with respect to the end face of each conductive layer that is considered to occur in the manufacturing process of the contact probe 11. It should be sufficiently larger than That is, the amount by which the end face 21a protrudes from the other end faces 22a and 23a is sufficiently larger than the unevenness at the joint surface that occurs accidentally during manufacturing.

  Thus, by projecting only the outer conductive layer 21, a step is formed on the joint surface to be joined to the probe substrate 12. Thereby, compared with the case where a joint surface is flat, since a contact surface with the probe board | substrate 12 becomes wide, resistance of a contact part can be made small and favorable electroconductivity can be acquired.

  Further, when the contact probe 11 is mounted on the probe substrate 12, the uneven state of the joint surface to be bonded to the probe substrate 12 is uniform for each contact probe 11, so that the direction in which the contact probes 11 are tilted is matched between the contact probes 11. be able to.

  FIG. 3 is a side view showing a main part of the probe card 10 of FIG. 1, and shows a plurality of contact probes 11 in which the joint 1 is soldered to the electrode pad 31 on the probe substrate 12. Each contact probe 11 has a bonding portion 1 bonded to an electrode pad 31 provided on the probe substrate 12 at regular intervals via solder 20a. The solder 20a is obtained by solidifying the low melting point layer 20 that is heated and melted at the time of joining.

  In this probe card 10, the unevenness of the end faces 21 a to 23 a in the joint portion 1 is uniform for each contact probe 11, and therefore the direction and amount of tilting with respect to the arrangement direction of the contact probes 11 (the left-right direction in FIG. 3) Match for contact probes.

  In this example, each contact probe 11 is formed by protruding the left conductive layer 21, and the right corner of the right conductive layer 23 and the right corner of the left conductive layer 21 are in contact with the electrode pad 31. Each contact probe 11 is tilted to the right.

  In this way, since the direction and amount of tilting are the same for each contact probe 11, the position of the contact portion 4 is prevented from varying in the arrangement direction and the height direction from the probe substrate 12 (vertical direction in FIG. 3). be able to. Further, it is possible to prevent the adjacent contact probe 11 from coming into contact and short-circuiting.

<Contact probe formation process>
4 to 6 are cross-sectional views schematically showing a process of forming the joint 1 of the contact probe 11 of FIG. FIG. 4A shows a silicon substrate 40 for forming a contact probe on which a sacrificial layer 41 is formed. When forming the junction 1 of the contact probe 11, first, a sacrificial layer 41 made of a conductive material different from the conductive layers 21 to 23 is formed on the silicon substrate 40 for forming the contact probe.

  FIG. 4B shows a silicon substrate 40 in which a resist layer 42 is formed on the sacrificial layer 41 in FIG. 4A, and the conductive layer 21 is formed in a portion where the resist layer 42 is removed. Yes. After the sacrificial layer 41 is formed, a photoresist made of a photosensitive organic material is applied on the sacrificial layer 41 to form a resist layer 42. Then, a patterning mask (first mask) is formed on the surface of the resist layer 42, and the resist layer 42 is partially exposed by selectively exposing the surface of the resist layer 42.

  In the portion where the resist layer 42 is removed in this way, the first conductive layer 21 is formed by electroplating.

  FIG. 4C shows the silicon substrate 40 from which the resist layer 42 of FIG. 4B has been completely removed. After the formation of the conductive layer 21, the resist layer 42 is completely removed.

  FIG. 4D shows a silicon substrate 40 in which a sacrificial layer 43 is formed on the sacrificial layer 41 and the conductive layer 21 of FIG. 4C and the surface of the sacrificial layer 43 is polished until the conductive layer 21 is exposed. Has been. A sacrificial layer 43 is formed on the sacrificial layer 41 and the conductive layer 21 exposed by removing the resist layer 42 by electroplating. The surface of the sacrificial layer 43 is polished until it is completely exposed. The sacrificial layer 43 is used to form the contact portion 4 on the needle tip portion 3.

  5A, a silicon substrate 40 in which a resist layer 44 is formed on the conductive layer 21 and the sacrificial layer 43 in FIG. 4D, and the conductive layer 22 is formed in a portion where the resist layer 44 is removed. It is shown. A photoresist is applied on the conductive layer 21 and the sacrificial layer 43 that are made smooth, and a resist layer 44 is formed.

  Then, a patterning mask (second mask) is formed on the surface of the resist layer 44, and the surface of the resist layer 44 is selectively exposed to remove the resist layer 44 in a region facing the conductive layer 21. The In the portion where the resist layer 44 is removed, the second conductive layer 22 is formed by electroplating.

  FIG. 5B shows the silicon substrate 40 in which the resist layer 44 of FIG. 5A is completely removed and then the sacrificial layer 45 is formed and polished. On the sacrificial layer 43 and the conductive layer 22 exposed by removing the resist layer 44, a sacrificial layer 45 is formed by electroplating, and the surface of the conductive layer 22 is removed in order to remove the extra sacrificial layer 45 formed. The surface of the sacrificial layer 45 is polished until it is completely exposed. The sacrificial layer 45 is used to project the end face of the third conductive layer 23 from the end face of another conductive layer.

  5C shows a silicon substrate 40 in which a resist layer 46 is formed on the conductive layer 22 and the sacrificial layer 45 in FIG. 5B, and the conductive layer 23 is formed on the portion where the resist layer 46 is removed. It is shown. A photoresist is applied on the smooth conductive layer 22 and the sacrificial layer 45 to form a resist layer 46.

  Then, a patterning mask (third mask) is formed on the surface of the resist layer 46, and the surface of the resist layer 46 is selectively exposed, whereby the region facing the conductive layer 22 and the conductivity of the sacrificial layer 45 are exposed. The resist layer 46 in the region facing the end on the layer 22 side is removed. A third conductive layer 23 is formed by electroplating in the portion where the resist layer 46 has been removed.

  The resist pattern formed by the third mask is a pattern in which a portion that becomes the end surface 21a is protruded from the resist pattern formed by the first and second masks.

  FIG. 5D shows the silicon substrate 40 from which the resist layer 46 of FIG. 5C has been completely removed. After the formation of the third conductive layer 23, the resist layer 46 is completely removed.

  FIG. 6A shows a silicon substrate 40 in which a resist layer 47 is formed on the conductive layer 23 and the sacrificial layer 45 in FIG. 5D, and the resist layer 47 is partially removed. Photoresist is applied again on the conductive layer 23 and the sacrificial layer 45 after the resist layer 46 is removed, and a resist layer 47 is formed.

  Then, by selectively exposing the surface of the resist layer 47, the resist layer 47 in a region facing the end face 21a is removed.

  FIG. 6B shows the silicon substrate 40 from which the sacrificial layers 45, 43, and 41 where the resist layer 47 of FIG. 6A has been removed are removed by etching. The sacrificial layer 45 exposed in the portion where the resist layer 47 has been removed, and the sacrificial layers 43 and 41 facing below the sacrificial layer 45 in that portion are removed by etching. Thereby, the end faces 21a to 23a are exposed, and a space 48 is formed in front of these end faces.

  This space 48 is adjacent to the end faces of all the conductive layers constituting the joint 1, and the low melting point layer 20 is formed in the space 48 thus formed. Here, in the state shown in FIG. 6B, the surface of the silicon substrate 40 having no conductivity is exposed through the space 48. Therefore, when a plating layer is formed in the space 48 by electroplating, the plating layer is formed on the end surfaces adjacent to the space 48 in the conductive layers 21 to 23 and the sacrificial layers 41, 43 and 45 made of a conductive material. Will be formed.

  FIG. 6C shows a silicon substrate 40 in which a plating layer 49 made of a conductive material having a low melting point is formed in the space 48 of FIG. 6B. In the space 48, the conductive layers 21 to 23 and the portions along the respective end surfaces of the sacrificial layer 41 where these conductive layers are laminated, the sacrificial layer 41 where these conductive layers are not laminated, and this A plating layer 49 composed of portions along the end faces of the sacrificial layers 43 and 45 laminated on the sacrificial layer 41 is formed by electroplating.

  FIG. 6D shows the silicon substrate 40 in which the surface of the resist layer 47 and the plating layer 49 is polished until the third conductive layer 23 is completely exposed after the formation of the plating layer 49 in FIG. 6C. Has been. In order to remove the excessively formed plated layer 49, the surfaces of the resist layer 47 and the plated layer 49 are polished until the third conductive layer 23 is completely exposed, whereby the low melting point layer 20 is formed on the end surface of the base. The joined portion 1 is completed.

  When the resist layer 47 is completely removed from the structure thus formed and the sacrificial layers 45, 43 and 41 are further removed, the contact probe 11 as shown in FIG. 2 is completed.

  According to the present embodiment, since the uneven state of the joint surface to be joined to the probe substrate 12 is uniform for each contact probe 11, the direction in which the contact probes 11 fall can be matched between the contact probes 11. Therefore, it is possible to reduce the mounting pitch when a large number of contact probes 11 are arranged on the probe substrate 12. Further, since the unevenness is formed on the joint surface by projecting the end surface of the conductive layer toward the probe substrate 12, the contact surface with the probe substrate 12 can be widened, and the increase in resistance at the contact portion can be suppressed. it can.

Embodiment 2. FIG.
In the first embodiment, the example in which the joint portion 1 is formed by projecting the end face 21a of the outer conductive layer 21 beyond the end faces of the other conductive layers 22 and 23 has been described. In contrast, in the present embodiment, a case will be described in which the end face of the conductive layer forming the contact portion 4 is protruded from the end faces of other conductive layers.

  FIG. 7 is a diagram showing a configuration example of the contact probe 51 according to the second embodiment of the present invention. Compared with the contact probe 11 of FIG. 2, the contact probe 51 is different in the uneven state of the end faces 21 a to 23 a in the joint portion 1.

  In the contact probe 51, the joint portion 1 is formed by projecting the end face 22 a formed by the central conductive layer 22 beyond the end faces 21 a and 23 a of the other conductive layers 21 and 23. That is, the center layer of the three conductive layers constituting the contact probe 51 forms an end face that protrudes most in the joint portion 1. Further, the conductive layer 22 that forms the contact portion 4 forms the end face that protrudes most in the joint portion 1.

  FIG. 8 is a side view showing the main part of the probe card 10 formed using the contact probe 51 of FIG. In this probe card 10, since the concave and convex states of the end faces 21 a to 23 a in the joint portion 1 are uniform for each contact probe 51, the direction and amount of collapse are the same between the contact probes 51.

  In this example, each contact probe 51 is formed by projecting the central conductive layer 22, the entire end surface 22 a of the conductive layer 22 contacts the surface of the electrode pad 31, and each contact probe 51 almost falls down. Arranged without.

  According to the present embodiment, since the conductive layer 22 forming the contact portion 4 forms the end face 22a that protrudes most in the joint portion 1, the height of the contact portion 4 with respect to the probe substrate 12 can be stabilized. it can. In addition, since the balance with respect to the arrangement direction of the contact probes 51 is improved as compared with the case where the conductive layers other than the central conductive layer are protruded, the contact probes 51 can be prevented from falling down.

It is the figure which showed an example of the probe card 10 by Embodiment 1 of this invention. FIG. 2 is a view showing a configuration example of a main part of the probe card 10 of FIG. 1, and shows a contact probe 11 formed on a probe substrate 12. FIG. 2 is a side view showing the main part of the probe card 10 of FIG. 1, and shows a plurality of contact probes 11 soldered to electrode pads 31 on a probe substrate 12. FIG. 3 is a cross-sectional view schematically showing a process of forming the joint portion 1 of the contact probe 11 of FIG. 2 and shows a process until a sacrificial layer 43 for forming the contact part 4 is formed. FIG. 3 is a cross-sectional view schematically showing a process of forming the joint portion 1 of the contact probe 11 of FIG. 2, showing a process until a third outer layer 21 is formed. FIG. 3 is a cross-sectional view schematically showing a process of forming the joint portion 1 of the contact probe 11 of FIG. 2 and shows a process until a low melting point layer 20 is formed. It is the figure which showed one structural example of the contact probe 51 by Embodiment 2 of this invention. It is the side view which showed the principal part of the probe card 10 formed using the contact probe 51 of FIG. It is the figure which showed the conventional contact probe. FIG. 2 is a view showing a conventional probe card, and shows a plurality of contact probes 100 soldered to electrode pads 210 on a probe substrate 200.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Junction part 2 Beam part 3a End surface 4 Contact part 10 Probe card 11 Contact probe 12 Probe board 13 External terminal 20 Low melting point layer 21-23 Conductive layer 21a-23a End surface 31 Electrode pad 51 Contact probe

Claims (3)

In a probe card comprising a probe board and a plurality of contact probes which are joined in a flat plate shape with their end faces butted on the probe board,
The probe card, wherein the plurality of contact probes are formed by laminating a plurality of conductive layers, the end face is uneven, and the positions of the layers protruding from the end face are the same. The contact probe has a contact portion formed by projecting a part of the conductive layer from another conductive layer toward the inspection object,
2. The probe card according to claim 1, wherein the conductive layer forming the contact portion forms a layer that protrudes most in the end face.   3. The probe card according to claim 1, wherein the contact probe is formed by laminating three conductive layers, and a central layer forms a layer that protrudes most in the end face. .

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