JP5282873B2 - A pair of probes for substrate inspection and a jig for substrate inspection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pair of probes for substrate inspection capable of performing four-terminal measurement, even with respect to a high-density wiring pattern. <P>SOLUTION: Each of the pair of probes has a contact part which is to be brought into contact with an inspection point on a substrate to be inspected, and one probe is used as a probe for signal measurement; and the other is used as a probe for signal supply. At least a part of the contact part of one probe of the pair of probes is positioned inside the other probe. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a pair of probes for board inspection for measuring a resistance value between wiring patterns on a circuit board and a disconnection inspection, and a jig for board inspection.

  The term “circuit board” used in the application documents is not limited to a package substrate for a semiconductor package or a film carrier, but a printed wiring board, for example, a flexible board, a multilayer wiring board, an electrode plate for a liquid crystal display or a plasma display, etc. A generic term for substrates to which various wirings are applied. That is, the circuit board includes all boards that can be subjected to four-terminal measurement.

  In recent years, in order to conduct continuity tests by accurately measuring not only continuity but also circuit board wiring resistance, four-terminal measurement has been used that can measure the resistance value without the influence of probe contact resistance. ing.

In such a four-terminal measurement, it is necessary that the voltage measurement probe and the current application probe be arranged as close as possible and reliably contact the same inspection point, and various means have been proposed.
JP 2005-315775 A discloses a configuration in which two probes are arranged in parallel and brought into contact with a pad at a point to be inspected.

  As described above, the four-terminal measurement performed by arranging two probes in parallel can be easily handled when inspecting a wiring pattern having a wide wiring pitch interval, but the wiring pitch is relatively small. When targeting a substrate on which a narrow and high-density wiring pattern is formed, there is a face that is difficult to cope with.

  Further, when two probes arranged in parallel on a spherical solder bump are brought into contact with each other, the two probes come into contact with the spherical surface descending in the opposite direction, so that they tend to be separated from each other. .

  A pair of probes and substrates for substrate inspection that can increase the number of four-terminal probes per unit area in order to perform four-terminal measurement on an inspection substrate on which a wiring pattern with a narrow wiring pitch and a high density is formed Provide inspection jigs.

  Further, even when two probes are brought into contact with a solder bump having a spherical surface, a pair of probes for substrate inspection and a substrate inspection jig capable of reliably bringing the two probes into contact with the solder bumps are provided. provide.

  In order to solve the above-mentioned problems, each of the pair of probes for inspecting a substrate according to the present invention has a contact portion that contacts an inspection point on the inspected substrate, and one of the probes is used as a probe for signal measurement The other is used as a signal supply probe, and at least a part of the contact portion of one probe is located inside the other probe.

  In a pair of probes, at least a part of the other probe is made of a wall surface having an opening along the longitudinal direction, and a part of the main body of one probe is inserted into the opening, thereby a part of the contact portion of one probe However, it may be located inside the other probe.

  The opening may be a slit, and the pair of probes may be flexible and elastic.

  In addition, each probe according to the present invention includes a member arranged so as to surround the space so that a space is formed therein, and a contact portion that contacts a point to be inspected on the substrate to be inspected. One of them can be used as a signal measurement probe, and the other can be used as a signal supply probe. Openings are formed on the side surfaces of the members of each probe, and the openings of the other probe members are formed in the openings. By inserting a part of the probe, a part of the contact portion of one probe is positioned inside the other probe.

  In addition, each of the substrate inspection jigs according to the present invention has a contact portion that contacts an inspection point on a substrate to be inspected, one of which is used as a signal measurement probe, and the other is for signal supply. A pair of probes used as probes, wherein at least part of the contact portion of one probe is provided with a plurality of pairs of probes located inside the other probe, and signals in the plurality of pairs of probes A probe for supply is connected to the signal generation unit, a probe for signal measurement is connected to the signal measurement unit, a holding plate that holds them, and a guide plate that holds and guides the vicinity of the contact part, A microspring is arranged between the holding plate and a plurality of pairs of probes.

  According to the present invention, it is possible to provide a pair of probes for substrate inspection and a substrate inspection jig that can easily perform four-terminal measurement even for a high-density wiring pattern.

  Further, according to the present invention, it is possible to provide a pair of probes for substrate inspection and a substrate inspection jig that can increase the density of the probes of the substrate inspection jig.

  Furthermore, according to the present invention, there is provided a pair of probes for substrate inspection and a substrate inspection jig capable of bringing a pair of probes into contact with an inspection point having a spherical surface such as a solder bump more reliably. Can do.

Hereinafter, preferred embodiments of a probe according to the present invention will be described with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
[4-terminal measurement]
FIG. 1 is a diagram for explaining the concept of four-terminal measurement. As shown in FIG. 1, when measuring the resistance 14 of the wiring of the circuit board 16, the first and second voltage probes 12S1, 12S2 and the first and second current probes 10F1, 10F2 are connected to the resistance of the wiring. 14 is arranged so as to be in contact with both ends, and a current of a predetermined magnitude for measurement is supplied from the current generator 10 to the wiring resistor 14 via the first and second current probes 10F1 and 10F2.

  As a result, a potential difference is generated at both ends of the resistance 14 of the wiring, and the voltage measurement unit 12 measures the potential difference between the both ends via the first and second voltage probes 12S1 and 12S2. When the value of the potential difference, that is, the voltage value is obtained, the resistance value of the wiring resistor 14 can be obtained from the current value for measurement and the measured voltage value.

In this measurement, the resistance values of the wirings between the pair of first current probes 10F1 and the first voltage probe 12S1 and between the other pair of first current probes 10F2 and the first voltage probe 12S2 are calculated. It is desirable that the distance between them is small so that it can be ignored.
[Configuration of probe for substrate inspection]
FIG. 2 shows a preferred embodiment of a pair of probes constituting a substrate inspection jig according to the present invention for inspecting a wiring pattern on a substrate by four-terminal measurement. The pair of probes includes a voltage probe 20S and a current probe 20F. These probes are, for example, a combination of substantially cylindrical members having a cross-sectional diameter of 50 to 100 μm and a thickness of 10 to 15 μm. Each of these probes has a slit with a uniform width along the longitudinal direction. 22 and 23 (openings) are formed. A part 24 of the current probe 20F is inserted through the slit 22 of the voltage probe 20S, and a part 26 of the voltage probe 20S is inserted through the slit 23 of the current probe 20F. The width of the slit is formed over about 10 to 20 μm. By changing the width of the slit, it is possible to change the length of the portion where each part of the two probes enters the other. The width of the slit 22 is not particularly limited as long as it can enter the inside of the other probe as described above, but is at least larger than the thickness of the cylindrical probe (including the thickness of the insulating film) and about 1/4 of the entire arc. A size of up to is preferred. For example, when the largest slit is used, the slit 22 may be formed by cutting out the length of an arc that is a quarter of the circumference of the voltage probe 20S.

  Here, the inside of the probe is an internal space formed by the wall surface forming the probe, and in the embodiment of FIG. 2, the inside of the cylinder of the cylindrical probe is indicated. By accommodating the other probe in the internal space of the pair of probes, the cross-sectional area (the cross-sectional area in the plane) becomes smaller than the total cross-sectional area of the two probes.

  The size of the slit 22 in the length direction is formed over the entire length in the length direction in FIG. 4, but if the pair of probes can be used in combination, the slit 22 can be formed over the entire length. It is not limited to. However, it is desirable to have at least half the total length of the probe.

  An insulating film is covered over the entire surfaces of the voltage probe 20S and the current probe 20F, and the end faces of the slits 22 and 23 are also covered with an insulating film. Therefore, as shown in FIG. 2, the insulation between the voltage probe 20S and the current probe 20F is maintained even in a state where the probe portions 24 and 26 are inserted into the slits 22 and 23, respectively.

  Although the thickness of this insulating film is not particularly limited, it is formed to be 1 to 10 μm, and is formed at a portion excluding both ends of the probe. The size of the portion to be excluded is not particularly limited, but it is necessary to have a length that allows reliable contact with the abutting inspection point and other members.

  At the time of substrate inspection, two pairs of probes configured as shown in FIG. 2 are used, one pair as a first current probe and voltage probe, and the other pair as a second current probe and voltage probe. To do. The tip of the probe that contacts the inspection point may be formed in a sawtooth shape or a sharp shape.

  FIG. 3A is a partial cross-sectional side view for explaining a state where four-terminal measurement is performed using two pairs of probes 20-1 and 20-2. The object to be inspected is the resistance value and disconnection of the wiring 36 between the solder bumps 30 and 31 of the wiring pattern portion having a relatively narrow wiring pitch and a high density formed on the front side of the substrate 34 (upper side in FIG. 3A). Presence or absence.

  The two pairs of probes 20-1 and 20-2 have the same structure. For example, the pair of probes 20-1 includes a probe 20F1 connected to the current generation unit and a probe 20S1 connected to the voltage measurement unit. Each of the probe 20F1 and the probe 20S1 is formed with slits 22 and 23 as shown in FIG. 2, and parts 24 and 26 of the probes are inserted between the slits. The contact portions 24C and 26C at the ends of the probe 20F1 and the probe 20S1 are in contact with the solder bumps 31. The other pair of probes 20-2 includes a probe 20F2 connected to the current generation unit and a probe 20S2 connected to the voltage measurement unit. Similarly, as shown in FIG. 2, the probes 20F2 and the probe 20S2 are formed with slits 22 and 23, respectively, and a part of the probes 24 and 26 are inserted between the slits 22 and 23, respectively. ing. The contact portions 24C and 26C at the ends of the probe 20F2 and the probe 20S2 are in contact with the solder bump 30. The diameter of the solder bump formed on the substrate is, for example, 40 to 200 μm.

  FIG. 3B shows an enlarged view of a portion surrounded by a dashed ellipse A in FIG. 3A. As is apparent from the figure, the contact portions 24C and 26C at the ends of the probes 20F2 and 20S2 are in contact with positions slightly below the top of the solder bumps 30 that are slightly displaced in the horizontal direction. Further, the contact part 24C of the part 24 of the probe 20F2 is located inside the probe 20S2, and conversely, the contact part 26C of the part 26 of the probe 20S2 is located inside the probe 20F2.

  FIG. 3C is a schematic view for explaining the arrangement and movement of the probe when the current probe 20F and the voltage probe 20S according to the present invention are brought into contact with the solder bump 35. FIG. As shown in FIG. 2, the pair of probes is a combination of the slits 22 and 23 inserted through the parts 24 and 26 of the mutual.

  As shown in FIG. 3C, when the contact portions 24C and 26C at the ends of the current probe 20F and the voltage probe 20S are pressed against the solder bump 35, the solder bump 35 has a curved surface, and therefore, the contact portions thereof. 24C and the contact part 26C try to slide down to the lower left and the lower right, respectively, toward the drawing. Along with this, the parts 24 and 26 of the current probe 20F and the voltage probe 20S try to move in the left and right directions, respectively. That is, the current probe 20F attempts to move to the left as indicated by the arrow MF, while the voltage probe 20S attempts to move to the right as indicated by the arrow MS. Therefore, they are close to each other. As a result, the current probe 20F and the voltage probe 20S come into contact with each other and stop moving, so that the force for pressing the probes against the solder bumps 35 is an axis for effectively bringing the probes into contact with the solder bumps. It will be used as a force in the direction.

  Further, as apparent from FIG. 3C, since the width of the current probe 20F and the voltage probe 20S is smaller than the total value of the respective diameters, the arrangement density of the probes can be increased.

  On the other hand, FIG. 3D shows a state in which two probes 12S and 10F are brought into contact with the solder bump 35 in a state of being arranged in parallel as in the prior art. In this state, when each probe is pressed against the solder bump 35, the contact portion 12C of the probe 12S located on the left side moves so as to slide down the left inclined surface of the solder bump 35, and the probe 10F located on the right side. The contact portion 10 </ b> C moves so as to slide down the right inclined surface of the solder bump 35. Accordingly, the wall surfaces 12P and 10P move to the left (arrow MS direction) and the right (arrow MF direction), respectively, so that the probes 12S and 10F move away from each other. That is, the force applied to press the probes 12S and 10F against the solder bumps 35 functions as a force in a direction in which the probes and the solder bumps 35 are separated from each other. It is not functioning effectively as a force.

  Next, a method for assembling the probe according to the present invention will be described with reference to FIGS. FIG. 4 is a plan view and a side view of one probe 20. As shown in the figure, a cylindrical member having a space inside is used as a probe member. A slit 22 is formed along the longitudinal side surface of the probe. The width of the slit 22 needs to be large enough to allow at least part of the other probe member to be inserted. The slit can be processed using, for example, a laser. After the slit is formed, the entire surface is covered with an insulating film except for the surfaces of the upper and lower end portions.

  FIG. 5 is a plan view and a side view showing a process in the middle of preparing two probes shown in FIG. 4 and combining them. In this case, one slit has a part 24 of the other probe 20 </ b> F inserted in the slit 22 of the probe 20 </ b> S and a part 26 of the other probe 20 </ b> S inserted in the other slit 23.

  FIG. 6 is a plan view and a side view showing a state in which the other parts 26 and 24 are completely inserted into the slits 23 and 22 of the probes 20F and 20S, respectively. The probe pair is used as a pair of voltage and current probes.

  FIG. 7 shows a schematic flow of the assembly process of a pair of probes. First, in step S71, two cylindrical probe members are prepared. Next, in step S72, as shown in FIG. 4, the side surface of each probe member is irradiated with a laser along the longitudinal direction to remove a predetermined width portion to form a slit. The wider the slit, the smaller the width in the diameter direction of the pair of probes when two probes are combined. In step S73, after the slit is formed, an insulating film is coated on the entire surface of each probe. However, the surfaces of both end portions in the longitudinal direction for making electrical contact are excluded. Next, in step S74, first, two probes are arranged in series in the longitudinal direction, and a part of one of the two probes is inserted into the slit of the other probe as shown in FIG. Then, it is slid and moved relatively in the longitudinal direction, and as shown in FIG. 6, the entire length of a part of each probe is inserted into the slit of the other probe.

  FIG. 8 shows an example of a state in which three pairs of voltage and current probes 20-1, 20-2 and 20-3 are in contact with the solder bumps 30 on the inspection substrate 80. These probes are formed of a material having flexibility and elasticity, and an end portion thereof is held by the base plate 86 through the intermediate plate 84. Further, the leading end portions thereof are guided to related solder bumps by the guide plate 82. The fixed ends are connected to a current generator and a voltage measuring unit (not shown), respectively.

  In FIG. 8, the base plate 86 and the intermediate plate 84 are lowered to bring the contact portions 24C, 26C of the three pairs of voltage and current probes 20-1, 20-2, 20-3 into contact with the solder bumps. If the descent continues, the voltage and current probes 20-1 and 20-2 that were straight at the beginning are bent and curved as shown in FIG. This is because the surface of the substrate 80 and the wiring circuit is uneven, or the height of the solder bumps is slightly different, so the distance between the intermediate plate 84 and the top surface of the solder bumps may be different. This is because the difference in distance is absorbed by the bending and bending of each probe in accordance with the difference. Since the probe has elasticity, it can return to its original straight state when it is lifted away from the solder bump.

  9 differs from FIG. 8 in that three pairs of voltage and current probes 20-1, 20-2, and 20-3 are brought into contact with the solder bumps 30 on the test substrate 80 using the microspring 88. FIG. An example of a state is shown. These probes abut against the lower end surface of the microspring 88 disposed in the base plate 86 through the intermediate plate 84 at the end. Similarly to FIG. 8, the tip end for measurement is guided to an appropriate solder bump by the guide plate 82. The end portions of the probes are connected to the current generation unit and the voltage measurement unit, respectively.

In FIG. 9, the base plate 86 and the intermediate plate 84 are lowered to bring the contact portions 24C, 26C of the three pairs of voltage and current probes 20-1, 20-2, 20-3 into contact with the solder bumps. As the descent continues, the microspring is pushed from the end of the probe and contracts. The contracted length corresponds to the difference in the distance between the intermediate plate 84 and the top surface of the solder bump, as in the case of FIG. Thereby, it is possible to absorb errors due to the unevenness of the surface of the substrate 80 and the wiring circuit and the difference in the height of the solder bumps. Further, the contact portions 24C and 26C of the probe can be brought into contact with the surface of the solder bump more reliably by the biasing force of the microspring.
[Alternative examples]
The preferred embodiment of the substrate inspection jig according to the present invention has been described above, but the present invention is not limited to the embodiment, and additions, deletions, modifications, etc. that can be easily made by those skilled in the art It should be understood that it is included in the invention. The technical scope of the present invention is defined by the description of the appended claims.

  In the above embodiment, an example of a probe having a cylindrical cross section in the diametrical direction has been described, but even if it is not cylindrical, for example, a U shape, a V shape, a C shape, Any shape may be used as long as the shape has a notch in part.

FIG. 1 is a diagram for explaining the concept of the four-terminal measurement method. FIG. 2 is a perspective view of an embodiment of a pair of probes used in the substrate inspection jig according to the present invention. FIG. 3A is a partial cross-sectional side view showing a state where two pairs of probes of the board inspection jig according to the present invention are brought into contact with solder bumps of a board to be inspected. FIG. 3B is an enlarged view of a portion surrounded by a dashed ellipse in FIG. 3A. FIG. 3C is a side view for explaining a state in which a pair of probes of the board inspection jig according to the present invention are in contact with solder bumps. FIG. 3D is a side view for explaining a state in which two conventional probes are arranged in parallel and brought into contact with solder bumps. 4A and 4B are a plan view and a side view for explaining one probe used in the substrate inspection jig according to the present invention. FIG. 5 is a plan view and a side view for explaining a process of assembling a pair of probes used in the board inspection jig according to the present invention. 6A and 6B are a plan view and a side view for explaining a state in which a pair of probes used in the board inspection jig according to the present invention is assembled. FIG. 7 is a flowchart showing an assembly process of a pair of probes used in the board inspection jig according to the present invention. FIG. 8 is a side view showing an example of a state where three pairs of voltage and current probes are brought into contact with solder bumps on the inspection board. FIG. 9 is a side view showing another example of a state in which three pairs of voltage and current probes are in contact with solder bumps on the inspection board.

Explanation of symbols

10: Voltage measurement unit, 12: Current generation unit, 20-1, 20-2, 20-3: A pair of probes, 20S1, 20S2, 20S3: Voltage probe, 20F1, 20F2, 20F3: Current probe, 22, 23: Slit, 24, 26: part, 24C, 26C: contact part

Claims (5)

Each has a contact portion that contacts a point to be inspected on a substrate to be inspected, one is used as a signal measuring probe, and the other is a pair of probes used as a signal supplying probe,
At least a part of the other probe is a wall surface having an opening along the longitudinal direction, and a part of the main body of the one probe is inserted into the opening so that a part of the contact portion of the one probe Is a pair of probes located inside the other probe. The pair of probes according to claim 1, wherein the opening is a slit. The pair of probes according to claim 1, wherein the pair of probes has flexibility and elasticity. A pair of probes which consist of a member arrange | positioned so that a pair of probe of Claim 1 may surround the space so that a space may be formed in an inside.   Each has a contact portion that contacts an inspection point on a substrate to be inspected, one of which is used as a signal measurement probe and the other is a pair of probes used as a signal supply probe. At least a part of the probe is made of a wall surface having an opening along the longitudinal direction, and a part of the main body of the one probe is inserted into the opening so that a part of the contact portion of the one probe is A plurality of pairs of probes located inside the other probe, and
The signal supply probe of the plurality of pairs of probes is connected to the signal generation unit, the signal measurement probe is connected to the signal measurement unit, and a holding plate for holding them,
A guide plate for holding and guiding the vicinity of the contact portion,
A substrate inspection jig in which a microspring is disposed between the holding plate and the plurality of pairs of probes.

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