JP2009198238A - Probe needle and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe needle that stably measures the electrical characteristics of a measuring object, without causing large damages to the measuring object and suppresses adhesion of component material of the measuring object to the tip of the probe needle. <P>SOLUTION: In this probe needle 1 for measuring the electrical characteristic of the measuring object by bringing its tip A into contact with an electrode of the measuring object, and projections 2 of a square pyramid or triangular pyramid shape are formed in a matrix form at the tip A. The probe needle 1 comprises a process of preparing a metal conductor, having an insulating coating of a predetermined length where the insulating coating 6 is formed on the outer periphery of the metallic conductor 5; a projection forming process of forming the projections 2 of the square pyramid or triangular pyramid shape, having a vertex angle range of 35 to 125° in the matrix shape at a pitch of 4 to 20 μm at least at one tip A of the metal conductor, having an insulating coating, a process of peeling the insulating coating from the tip of a pre-probe needle having the projections 2, and a process of forming a plating layer on an exposing section from which the insulating coating is peeled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a probe needle for measuring the electrical characteristics of a measurement object by bringing the tip into contact with an electrode of the measurement object with a predetermined load and a method for manufacturing the probe needle.

  In recent years, various circuit boards such as high-density mounting boards used for mobile phones and the like, IC package boards such as BGA (Ball Grid Array) and CSP (Chip Size Package) incorporated in personal computers, etc., are often used. Yes. Such a circuit board is subjected to, for example, a measurement of a direct current resistance value or a continuity test in the processes before and after mounting, and the electrical characteristics of the circuit board are inspected. The inspection of electrical characteristics is performed using an inspection apparatus jig (hereinafter referred to as “probe unit”) connected to an inspection apparatus for measuring electrical characteristics. For example, a pin shape mounted on the probe unit is used. The probe needle (also referred to as a contact probe) is brought into contact with the electrode of the circuit board (hereinafter also referred to as “measurement object”) (see, for example, Patent Document 1).

  By the way, an insulating film such as an oxide film is easily formed on the surface of the electrode to be measured, and the resistance value (hereinafter referred to as “contact resistance value”) between the two is only when the probe needle is simply brought into contact with the electrode. It may be too high to be accurate. Therefore, a probe needle whose tip has been processed into a needle shape has been proposed. However, since the tip of the probe needle easily breaks through the insulating film on the electrode surface, the probe needle and the electrode are reliably in contact with each other, and the contact resistance The value decreases, and as a result, the accuracy of the inspection can be improved. However, such a probe needle has a problem that the needle-shaped tip may pierce deeply into the electrode of the object to be measured, and the electrode is easily damaged, and the electrode is easily deformed. There exists a problem that it adheres and the stability by repeated measurement falls.

To prevent such problems, the use of a probe needle with a flat or curved tip can prevent scratches on the electrode, but this probe needle has a contact resistance value with the electrode of the object to be measured. It cannot be lowered sufficiently. Thus, for example, Patent Document 2 proposes a probe needle in which square pyramidal protrusions are formed in a lattice shape at the tip. By using this probe needle, it is possible to disperse the load when the grid-like quadrangular pyramid projections come into contact with the electrode of the object to be measured, thus suppressing wear of the plating layer provided at the tip of the probe needle. It can be used for a long time.
JP 2002-131334 A JP 2007-218675 A

  The probe needle described in Patent Document 2 does not lower the contact resistance value by the protrusions penetrating the insulating film on the electrode, as described in the document, and the load at the time of contact is dispersed by the plurality of protrusions. Specifically, the height of the protrusion tip is changed or a minute flat portion is formed at the protrusion tip to prevent the plating layer from being worn, thereby realizing long-term use.

  However, although the probe needle described in Patent Document 2 can disperse the contact load on the electrode and the progress of wear of the plating layer at the tip of the probe needle may be delayed, it is formed on the electrode surface of the measured object. When the oxide film is relatively thick, the contact resistance value with the electrode cannot be lowered, and accurate electrical characteristics cannot be measured.

  The present invention solves the above-described problem, and the object of the present invention is to provide a probe needle for performing electrical measurement of a measured object by bringing the tip into contact with an electrode of the measured object. It is an object of the present invention to provide a probe needle that can stably measure the electrical characteristics of a measurement object without damaging it, and can prevent the constituent material of the measurement object from adhering to the tip of the probe needle. Another object of the present invention is to provide a method for stably producing such a probe needle with a high yield.

  A probe needle according to the present invention for solving the above-mentioned problems is a probe needle for measuring the electrical characteristics of a measured object by bringing the distal end into contact with an electrode of the measured object. Projections made of a quadrangular pyramid or a triangular pyramid having a vertex angle of not less than 125 degrees and not more than 125 degrees are formed in a matrix with a pitch of not less than 4 μm and not more than 20 μm.

  According to the present invention, since the tip of the quadrangular pyramid or the triangular pyramid projection is formed in the range of the vertex angle, the oxide film is formed even when the oxide film is formed on the electrode surface of the object to be measured. The contact resistance value can be lowered by breaking through, and the electrical characteristics of the measured object can be measured. Furthermore, since such an apex angle is an angle range in which the electrode material (for example, solder material) of the object to be measured is not transferred to the tip of the probe needle, the tip of the probe needle is not contaminated with the electrode material and can be used for a long time. Become. Furthermore, since the projections of such a quadrangular pyramid or a triangular pyramid are formed in a matrix within the above-mentioned pitch range, a plurality of projections simultaneously contact the electrode surface of the object to be measured to disperse the contact pressure to the electrode. Can do. As a result, the projection capable of breaking through the oxide film does not cause a large scratch or deformation on the electrode of the object to be measured. Therefore, according to the present invention, the contact resistance value of the measured object with respect to the electrode can be lowered to measure the accurate electrical characteristics of the measured object, and the electrode of the measured object is hardly damaged, and the probe needle Since it is possible to prevent the electrode material from being transferred to the tip and increase the contact resistance value, repeated measurement using a probe needle can be performed stably and accurately.

  The probe needle of the present invention may be configured so that at least the tip has at least one selected from gold plating, palladium plating, rhodium plating, and nickel plating.

  The probe needle of the present invention may be configured such that the portion other than the tip of the probe needle is covered with an insulating film.

  A method of manufacturing a probe needle of the present invention that solves the above-described problem is a method of manufacturing a probe needle for measuring the electrical characteristics of a measured object by bringing the tip into contact with an electrode of the measured object. A step of preparing a metal conductor with an insulating coating having a predetermined length in which an insulating coating is formed on the outer periphery of the metal conductor, and a quadrangular pyramid having a vertex angle of not less than 35 degrees and not more than 125 degrees at the tip of at least one of the metal conductors with an insulating coating Alternatively, a protrusion forming step of forming protrusions made of a triangular pyramid in a matrix shape with a pitch of 4 μm or more and 20 μm or less, a step of peeling off the insulating film at the tip of the pre-probe needle on which the protrusion is formed, and the insulating film peeling off And a step of forming a plating layer on the exposed portion.

  According to this invention, since the protrusion forming step is before the insulating film peeling step, the protrusion is processed under the condition that the tip of the metal conductor is wrapped with the insulating film. As a result, burrs are unlikely to occur in the metal conductor during processing, and if the insulating coating is peeled off after that, it can be put into the metal plating process as it is. Therefore, according to the method for manufacturing a probe needle of the present invention, the tips on which projections made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less are formed in a matrix at a pitch of 4 μm or more and 20 μm or less. The probe needle can be efficiently manufactured without an extra step such as deburring. The “pre-probe needle” is a probe needle intermediate product before the finished product.

  In the probe needle manufacturing method of the present invention, in the projection forming step, the projection made of the quadrangular pyramid is performed by orthogonal biaxial V-groove machining, and the projection made of the triangular pyramid intersects by 60 degrees. It is preferable to configure so that

  In the preparation step of the probe needle of the present invention, in the preparation step, the metal conductor with an insulating coating is formed by continuously applying an insulating coating on the outer periphery of a long metal conductor to form a long conductor with an insulating coating; It is preferable that the long conductor with an insulating coating is prepared through a step of cutting to a predetermined length.

  According to the probe needle of the present invention, (1) even when an oxide film is formed on the electrode surface of the object to be measured, the contact resistance value can be lowered by breaking through the oxide film. Electrical characteristics can be measured accurately, (2) The tip of the probe needle is not contaminated with electrode material, and it can be used for a long period of time. (3) Multiple protrusions can be simultaneously applied to the electrode surface of the object to be measured. The contact pressure on the electrode can be dispersed by contact, and the projection capable of breaking through the oxide film does not damage or deform the electrode of the object to be measured. Therefore, according to the present invention, repeated measurement using the probe needle can be performed stably and accurately.

  According to the probe needle manufacturing method of the present invention, burrs are unlikely to occur in the metal conductor during processing, and if the insulating film is subsequently peeled off, it can be put into the metal plating process as it is, so that it has a vertex angle of 35 ° to 125 °. A probe needle having a tip in which protrusions made of a quadrangular pyramid or a triangular pyramid are formed in a matrix with a pitch of 4 μm or more and 20 μm or less can be efficiently manufactured without going through an extra step such as deburring.

  Hereinafter, a probe needle and a manufacturing method thereof according to the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

(Probe needle)
FIG. 1 is a schematic diagram showing a probe needle 1 of the present invention. FIG. 2 is a schematic view showing an example in which the projection 2A at the tip A of the probe needle 1 of the present invention is a quadrangular pyramid, and FIG. 3 is a diagram of the projection 2B at the tip A of the probe needle 1 of the present invention being a triangular pyramid. It is the schematic which shows an example of a case. As shown in FIG. 1, the probe needle 1 of the present invention is a probe for measuring the electrical characteristics of a measured object 12 by bringing the tip A into contact with an electrode 11 of the measured object 12 (see FIG. 5). It is a needle. Then, on the tip A of the probe needle 1, projections 2 made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less are formed in a matrix with a pitch P of 4 μm or more and 20 μm or less.

  As the metal conductor 5, a metal wire (also referred to as “metal spring wire”) having high conductivity and high spring property is used. Examples of the metal used for the metal conductor 5 include metals having a wide elastic range, for example, copper alloys such as beryllium copper, phosphor bronze, copper silver alloy, tungsten, rhenium tungsten, steel (for example, high speed steel: SKH). Etc.) can be preferably used. Such metal conductor 5 is usually subjected to plastic working such as cold or hot wire drawing until the metal becomes a linear conductor of a predetermined diameter. The length is not particularly limited, and may be a length according to the specification. Further, the diameter of the metal conductor 5 is not particularly limited, but is preferably selected from the range of 20 μm or more and 250 μm or less so as to cope with the narrow pitch of the electrodes 11 provided on the recent measurement object 12.

  Protrusions 2 having a predetermined shape are provided at a tip end A of the metal conductor 5 at a predetermined pitch P in a matrix. The protrusion 2A shown in FIG. 2 has a quadrangular pyramid shape, and the protrusion 2B shown in FIG. 3 has a triangular pyramid shape (referred to simply as “protrusion 2” when these are collectively referred to). Normally, as shown in FIG. 2 and FIG. 3, it is preferably a regular quadrangular pyramid or a regular triangular pyramid, but it is formed in such a shape that the vertex 3 is shifted from the center of the pyramid, that is, the quadrangular pyramid or the triangular pyramid is inclined. May be.

  The apex angle of the protrusion 2 is preferably in the range of 35 degrees or more and 125 degrees or less. The protrusion 2 having an apex angle within such a range, when an oxide film having a high electrical resistance is formed on the surface of the electrode 11 of the object 12 to be measured, breaks through the oxide film and contacts the electrode 11 itself. Therefore, the electrical characteristics of the measurement object 12 can be accurately measured. Further, the apex angle in the above range is an angle range in which the electrode material (for example, solder material) constituting the electrode of the measurement object 12 is not transferred to the tip A of the probe needle 1, so that the tip A of the probe needle 1 is the electrode material. It can be used repeatedly for a long period of time and can be used stably for a long time.

  When the apex angle of the protrusion A is less than 35 degrees, the tip A of the probe needle 1 is easily pierced into the electrode 11, and as a result, the shear stress when pulled out from the pierced state becomes stronger, so the electrode material constituting the electrode 11 Has a problem in that it is easily transferred and attached to the tip A of the probe needle 1. Such adhesion of the electrode material (for example, solder) contaminates the tip A of the probe needle 1 with the fine powder of the electrode material, which causes the fine powder to oxidize and increase the contact resistance. On the other hand, when the apex angle of the protrusion A exceeds 125 degrees, it becomes difficult for the tip A of the probe needle 1 to break through the oxide film on the surface of the electrode 11, and the contact resistance value with the electrode 11 increases and the measured object 12. May not be able to evaluate the exact electrical characteristics of

  A more preferable range of the vertex angle of the protrusion A is not less than 40 degrees and not more than 120 degrees. The apex angle within this range has a characteristic effect that the electrode material is more difficult to transfer and can easily break through the oxide film on the electrode surface. In particular, the protrusion 2A made of a quadrangular pyramid preferably has an angle of 40 ° to 110 °, and the protrusion 2B made of a triangular pyramid preferably has an angle of 50 ° to 120 °.

  The apex 3 of the protrusion 2 is preferably acute enough to break through the oxide film. Specifically, the apex 3 does not have a flat part or a curved part, and is preferably sharp (see FIG. 6). In addition, as the electrode 11, although what normally has solder mounted on a copper pad is mentioned, it is not limited to this, Electrode 11, such as a gold pad and an aluminum pad, can be mentioned. The probe needle 1 of the present invention is preferably used as a contact with such an electrode 11.

  In the case of a quadrangular pyramid, the apex angle of the protrusion A is defined by a value measured as an angle between opposing inclined surfaces constituting the quadrangular pyramid. On the other hand, the triangular pyramid is defined as a value measured as an angle between one inclined surface constituting the triangular pyramid and two ridge lines of the inclined surfaces facing each other with the apex 3 interposed therebetween. It should be noted that instead of such vertex angle, it is expressed as an angle between a virtual surface when the protrusion 2 is formed on a plane and an inclined surface forming a quadrangular pyramid, or the virtual surface and a triangular pyramid are configured. It can be expressed as an angle with the inclined surface. When expressed in such an angle, a range from 72.5 degrees (corresponding to a vertex angle of 35 degrees) to 27.5 degrees (corresponding to a vertex angle of 125 degrees) can be shown.

  The protrusions 2 are formed in a matrix at the tip A of the probe needle 1. Specifically, as shown in FIG. 2, they are arranged in a direction intersecting at a predetermined pitch P of 90 degrees. Further, as shown in FIG. 3, they are arranged in respective directions intersecting at an angle of 60 degrees with a predetermined pitch P. The pitch P of the protrusions 2 is preferably 4 μm or more and 20 μm or less. At this time, when the quadrangular pyramids shown in FIG. 2 are formed in a matrix, the pitch P can be expressed by the distance between vertices of adjacent quadrangular pyramids, and the triangular pyramids shown in FIG. 3 are arranged in a matrix. If formed, the apex 3 between the nearest triangular pyramids can be represented by a value measured in a direction orthogonal to the direction in which one side is parallel. In addition, although it represents with the distance between the vertexes 3 and 3 here, you may represent with the distance between trough parts. A particularly preferable pitch P is 7 μm or more and 15 μm or less from the viewpoint of reducing contact resistance and making a scratch on the electrode to be measured inconspicuous.

  When the pitch P of the protrusions 2 is formed in a two-dimensional plane within the above range, the plurality of protrusions 2 at the probe needle tip A simultaneously contact the surface of the electrode 11. As a result, the contact pressure when the probe needle tip A contacts the electrode 11 can be distributed to the plurality of protrusions 2. Therefore, the protrusion 2 that can break through the oxide film does not damage or deform the electrode 11 of the measurement object 12. Moreover, since the plurality of protrusions 2 at the probe needle tip A can break through many places in the oxide film even in a pressure-distributed state, the contact resistance value between the probe needle 1 and the electrode 11 can be reduced, and as a result. Therefore, it is possible to perform stable measurement of electrical characteristics for a long time.

  When the pitch P of the protrusions 2 is less than 4 μm, the distance between the protrusions 2 is too small and the contact pressure is excessively dispersed in the many protrusions 2, so that the contact pressure with respect to one vertex 3 decreases, and the oxide film described above It becomes difficult to break through. On the other hand, when the pitch P of the protrusions 2 exceeds 20 μm, the distance between the protrusions 2 is too coarse, and the contact pressure is excessively concentrated on the plurality of protrusions 2. May cause large scratches or deformation. Such an excessive increase in contact pressure makes it easy for the apex 3 of the protrusion 2 to pierce deeply into the electrode, so that the electrode material easily adheres to the probe needle 1 and becomes one of the factors that increase the contact resistance value.

The pitch P is a distance between the apexes of the protrusions 2, but may be expressed as a protrusion density as a form of the protrusion 2. For example, in the case of a quadrangular pyramid having a vertex pitch of 10 μm, the density is approximately 10,000 / mm ² , and the density of the protrusions 2 formed with the pitch P of 4 μm to 20 μm is 62500 / mm ^{2 to} 2500 / mm ^2. It can be expressed as.

  The probe needle 1 of the present invention having such a characteristic tip shape can measure the accurate electrical characteristics of the measurement object 12 by reducing the contact resistance value of the measurement object 12 with respect to the electrode 11. It is difficult to damage the electrode 11, and it is possible to prevent the electrode material from being transferred to the probe needle tip A to prevent the contact resistance value from increasing, so that repeated measurement using the probe needle 1 can be performed stably and accurately. There is a special effect. Further, when the electrode 11 of the measurement object 12 is a solder bump, even if the contact position is slightly off the bump center, the protrusion 2 at the probe needle tip A grips on the solder bump, and the probe needle from the solder bump. 1 will not slide down.

  The shape of the rear end B, which is the end opposite to the tip A, is not particularly limited, and may be the same shape as the projection 2 as described above, and has a general conical shape and a hemispherical shape at the apex. Any one selected from a conical shape, a conical shape having a flat shape at the apex, and the like may be used. The “hemispherical shape” and “conical shape” here include an accurate hemisphere and a cone, but also include a substantially cone and a substantially hemisphere. Note that the end B may be processed by electrolytic polishing or wet etching, and in that case, the shape of the rear end B is slightly rounded, but is not necessarily limited to such a shape.

  The insulating coating 6 is provided on the outer periphery of the metal conductor 5 and prevents a short circuit by preventing electrical contact with the adjacent probe needle 1 when the probe needle 1 is attached to a probe unit 10 described later. Acts as follows. The insulating coating 6 may be provided on the outer periphery of the metal conductor 5 over the longitudinal direction, may be provided directly, or may be provided via another layer. In addition, since the front end A and the rear end B are in contact with the electrode 11 and the lead wire 50, respectively, the insulating coating 6 is peeled from the end by a predetermined length.

  The insulating coating 6 is not particularly limited as long as it is an insulating coating, but it is any one selected from polyurethane resin, nylon resin, polyester resin, epoxy resin, polyesterimide resin, polyamide resin and polyamideimide resin. Is preferred. Usually, it is formed of one kind of resin. Since the insulating film made of these resins has different heat resistance, it can be arbitrarily selected in consideration of the heat generated during the inspection. For example, when more heat resistance is required, the insulating coating 6 is preferably formed of a polyesterimide resin, a polyamideimide resin, or the like. Especially, it is preferable that the insulating film 6 is formed as a baking enamel film. As will be described later, the baking enamel coating is formed in a continuous process by repeated application of coating and baking, so that the productivity is good, the adhesiveness with the metal conductor 5 is high, and the coating strength is higher. be able to.

  The insulating coating 6 is provided to prevent a short circuit between adjacent probe needles 1. In the present invention, as shown in FIG. 5, the stepped portion 7, which is the end surface on the tip A side of the insulating coating 6, is a probe. It is preferable to have the action of preventing the probe needle 1 from falling by being caught on the guide plate 20 of the unit 10 or the action of locking the probe needle 1. The thickness of the insulating coating 6 for forming the stepped portion 7 having such an effect varies depending on the diameter of the metal conductor 5, but is preferably 5 μm or more and 20 μm or less, for example.

  A plating layer may be provided at the tip A or the rear end B of the probe needle in order to suppress an increase in the contact resistance value between the metal conductor 5 and the measured object 12 or the lead wire 50 of the inspection apparatus. . Examples of the metal constituting the plating layer include metals such as gold, palladium, rhodium, and nickel, and alloys such as gold alloys. The plating layer may be a single layer or a multilayer. Preferred examples of the multi-layered plating layer include those in which a gold plating layer is formed on a nickel plating layer. Since such a plating layer prevents the tip of the probe needle from being oxidized, a more stable contact resistance can be obtained, and a stable measurement over a longer period of time can be achieved.

  Further, from the viewpoint of facilitating the mounting of the probe needle 1 to the probe unit 10, the straightness of the metal conductor 5 is preferably high, and specifically, the straightness is preferably 1000 mm or more in terms of the radius of curvature R. The metal conductor 5 having high straightness can be usually obtained by performing straightening treatment in advance before the insulating coating 6 is provided. The straightening process here is performed, for example, by a rotary die type straightening apparatus or the like. The length of the probe needle 1 is not particularly limited, but is usually about 10 mm or more and 40 mm or less.

(Probe needle manufacturing method)
Next, a method for manufacturing the probe needle of the present invention will be described. The method for manufacturing the probe needle 1 according to the present invention is a method for manufacturing the probe needle 1 according to the present invention, wherein a metal conductor with an insulating coating having a predetermined length in which an insulating coating 6 is formed on the outer periphery of the metal conductor 5 is prepared. Forming a projection 2 made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less at a pitch of 4 μm or more and 20 μm or less at the tip A on the electrode side of at least the electrode side of the metal conductor with an insulating coating; A protrusion forming step, a step of peeling the insulating coating 6 at the tip of the pre-probe needle on which the protrusion 2 is formed, and a step of forming a plating layer on the exposed portion where the insulating coating 6 is peeled off. The “pre-probe needle” is a probe needle intermediate product before the finished product. Hereinafter, it demonstrates in order.

  The step of preparing a metal conductor with an insulating coating is a step of preparing a metal conductor with an insulating coating having a predetermined length in which an insulating coating 6 is formed on the outer periphery of the metal conductor 5. The metal conductor with an insulating coating may be prepared as a purchased product, or a step of continuously applying the insulating coating 6 on the outer periphery of the long metal conductor 5 to form a long conductor with an insulating coating, and the insulating coating You may prepare through the process of cut | disconnecting an attached long conductor to predetermined length. Moreover, the plastic processing process which processes the metal conductor 5 to a predetermined diameter may be included. The continuous coating of the insulating coating 6 may be performed in a process of baking the insulating coating 6 on the outer periphery of the metal conductor 5 using an enameled wire manufacturing apparatus. In addition, after cutting to a predetermined length, the rear end B of the probe needle 1 is ground or irradiated with a laser to remove the portion of the insulating film 6 that contacts the lead wire 50, and the metal conductor 5 is removed. You may make it expose.

  The projection forming step is a matrix-like projection 2 made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less at least at the tip A on the electrode side of the metal conductor with an insulating coating. It is the process of forming. In this projection forming step, it is preferable that the projection 2A made of a quadrangular pyramid is formed by orthogonal biaxial V-groove machining, and the projection 2B made of a triangular pyramid is made by triaxial V-groove machining intersecting at 60 degrees. Such grooving can be performed by using an appropriate means depending on the material of the metal conductor 5 to be processed, for example, by adopting precision machining means such as ultrasonic cutting or rotary grindstone processing. In this way, the matrix-shaped protrusions 2A and 2B shown in FIGS. 2 and 3 can be processed.

  In the present invention, such a process of forming the protrusions 2A and 2B is performed with V-groove processing in a state where the insulating coating 6 covers the outer peripheral end of the metal conductor 5 (the insulating coating 6 is not provided at the tip which is a cut end surface). There is also a feature. FIG. 4 is a configuration diagram when a V-groove is processed at the tip of a metal conductor with an insulating coating. In processing the V-groove, as shown in FIG. 4, the metal conductors with insulating coating are stacked, and the metal conductor with insulating coating does not shift during the V-groove processing by applying pressure F from at least one or two sides. To fix. In the present invention, since the insulating coating 6 is covered up to the outer peripheral end on the front end side of the metal conductor 5, when the pressure F is applied, the insulating coating 6 that is more elastic than the metal conductor 5 is adjacent to the metal with the insulating coating. The contact 8 is elastically deformed by pressing against the insulating coating 6 of the conductor, and grips each other. As a result, the tip of the metal conductor with an insulating coating is not displaced during the V-groove processing, so that accurate V-groove processing can be performed. Moreover, since the outer periphery is covered with the insulating coating 6 in close contact with the metal conductor 5, it is possible to prevent the metal conductor from sagging during the V-groove processing, and further, burrs are generated at the periphery of the metal conductor. There is an effect not seen in the prior art that can be prevented.

  The insulating coating peeling process is a process of peeling the insulating coating 6 at the tip of the pre-probe needle on which the protrusions 2 are formed. The means for the peeling at this time is not particularly limited as long as a predetermined length can be accurately peeled, but may be peeling by laser or mechanical peeling, for example. By this peeling step, the stepped portion 7 shown in FIG. 1 can be formed. The stepped portion 7 contacts the guide plate 20 of the probe unit 10 and acts to prevent the probe needle 1 from falling.

  The plating layer forming step is a step of forming a plating layer on the exposed portion from which the insulating coating 6 has been peeled off. The plating layer can be formed by wet plating such as electroplating or electroless plating using a plating solution selected from the above types. Moreover, you may form into a film by what is called PVD methods (dry plating), such as vapor deposition and sputtering.

  As described above, according to the method for manufacturing the probe needle 1 of the present invention, since the protrusion forming step is before the insulating film peeling step, the protrusion A is formed in a state where the tip A of the metal conductor 5 is wrapped with the insulating film 6. 2 is processed. As a result, burrs are unlikely to occur at the periphery of the metal conductor 5 during processing, and if the insulating coating 6 is subsequently peeled off, it can be directly put into the metal plating step without performing a deburring process or the like. Therefore, according to the method for manufacturing the probe needle 1 of the present invention, the projections 2 made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less are formed in a matrix with a pitch P of 4 μm or more and 20 μm or less. The probe needle 1 having the tip A can be efficiently manufactured without an extra step such as deburring.

(How to use the probe needle)
Next, an electrical property inspection method using the above-described probe needle 1 of the present invention will be described with reference to FIG. The probe needle 1 of the present invention is mounted on a probe unit 10 and used for checking the quality of electrical characteristics of a measured object 12 such as a circuit board. As shown in FIG. 5, the probe unit 10 includes a plurality of thousands of probe needles 1, a plate 20 that guides the probe needles 1 to the electrodes 11 of the object to be measured 12, and the probe needles 1 that lead the inspection apparatus. And a plate 30 that guides the wire 50. The plate 30 on the inspection apparatus side has a guide hole 31 that is slightly larger than the diameter of the probe needle 1, and the guide hole 31 guides each probe needle 1 to the lead wire 50. The plate 20 on the measured object side has a guide hole 21 slightly larger than the diameter of the metal conductor 5, and the guide hole 21 guides the tip A of the metal conductor 5 of each probe needle 1 to the electrode 11. .

  The step portion 7 provided in the probe needle 1 acts so as to hold the probe needle 1 so that it does not fall by hitting the guide plate 20 on the electrode 11 side.

  The position of the probe unit 10 and the measured object 12 are controlled so that the probe needle 1 and the electrode 11 of the measured object 12 correspond to each other when the electrical characteristics of the measured object 12 are inspected. The electrical property inspection is performed by moving either the probe unit 10 or the measured object 12 up and down and pressing the tip A of the probe needle 1 against the electrode 11 with a predetermined pressure using the elastic force of the probe needle 1. Is called. At this time, the rear end B of the probe needle 1 is in contact with the lead wire 50 at all times or at any time, and an electric signal from the measured object 12 is sent to the inspection device (not shown) through the lead wire 50. In addition, the code | symbol 40 in FIG. 5 shows the holding plate for lead wires.

  Unlike the conventional probe needle, the probe needle 1 of the present invention has an effect which is superior to that of the prior art by specifying the shape of the protrusion 2 and the pitch P. Therefore, the probe needle 10 is operated to operate the probe. If the needle 1 is pressed against the electrode 11, long-term stable measurement can be accurately performed.

  The present invention will be described more specifically by conducting the following experiments. Note that the following experimental results are merely examples, and the present invention is not limited to the following experimental results.

(Experimental example)
A number of samples with various apex angles and apex pitches P were produced and tested. First, a long tungsten wire (diameter: 90 μm) was used as the metal conductor 5. A polyurethane resin-based enamel paint was used as a coating for the insulating coating, and a polyurethane coating 6 having a thickness of 15 μm was continuously baked by an insulating coating baking apparatus (not shown) to produce a tungsten wire with an insulating coating. Next, it cut | disconnected to 30 mm length with the fixed length cutting device. Next, the tungsten wire with an insulating coating was stacked and fixed on a predetermined jig in the manner shown in FIG. 4, and the tip A was V-grooved. The V-groove processing was performed by ultrasonic cutting, the quadrangular pyramid was performed by orthogonal biaxial V-groove processing, and the triangular pyramid was performed by triaxial V-groove processing intersecting at 60 degrees. In the V-groove processing, the vertex angle and the vertex pitch P were variously changed to produce the forms shown in Table 1. In addition, the example of the form of the obtained quadrangular pyramid was shown in FIG. The center of FIG. 6 is a tungsten wire, and the outer peripheral part is a polyurethane resin layer.

  Thereafter, the excimer laser was irradiated to the tip A, and the insulating coating 6 having a thickness of about 2.5 mm was peeled off from the tip to produce the probe needle 1 having the mode shown in FIG. The rear end B of the probe needle 1 was ground into a hemispherical shape by a grinding machine. Further, on the tip A after peeling off the insulating coating 6, in order to prevent oxidation of the probe needle tip A and reduce the contact resistance value with the electrode 11, a 0.5 μm thick palladium plating is applied by electroplating. Formed. Thus, no. Samples 1 to 20 were prepared.

(Measurement and results)
Each sample obtained as described above is mounted on the probe unit 10 shown in FIG. 5, and the contact load is applied to the electrode 11 of bump (diameter 80 μm) made of solder (63% tin, 37% lead). Was repeatedly contacted as 10 g, and the contact resistance value, electrode appearance scratches, and electrode material adhesion at that time were evaluated. Moreover, comprehensive evaluation was performed based on the result. The contact resistance value is measured with a multimeter. When the contact resistance value after contacting the probe needle 1 and the electrode 11 1000 times with the load is 1.5Ω or more, “x” is indicated, and when the contact resistance value is less than 1.5Ω. Was marked as “◯”. Similarly to the above, the electrode appearance scratch was observed with a microscope magnified 300 times after the electrode 11 was contacted 1000 times, and “○” was indicated when it was an acceptable scratch (maximum scratch width was less than 10 μm). In the case of an unacceptable scratch (the maximum width of the scratch is 10 μm or more), “x” was given. In addition, as in the case of the electrode material adhesion, “◯” indicates that the probe needle tip A after 1000 times contact was observed with a microscope and was not adhered at all or was slightly adhered to the extent that the electrode material color was attached. The case where the pyramid was attached to such an extent that the outline of the pyramid was changed was defined as “x”. The results are summarized in Table 1.

It is a typical schematic diagram showing probe needle 1 of the present invention. It is the schematic which shows an example in case the processus | protrusion 2A of the front-end | tip A of the probe needle 1 of this invention is a quadrangular pyramid. It is the schematic which shows an example in case the processus | protrusion 2B of the front-end | tip A of the probe needle 1 of this invention is a triangular pyramid. It is explanatory drawing of the process of forming the processus | protrusion 2 of the front-end | tip A of the probe needle 1 of this invention. It is a typical block diagram which shows the structural example of the probe unit 10 equipped with the probe needle 1 of this invention. It is an electron micrograph which shows the front-end | tip shape of the probe needle 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probe needle 2, 2A, 2B Protrusion 3 Vertex 4 Valley part 5 Metal conductor 6 Insulation film 7 Step part (contact part)
A front end B rear end P pitch F weight 11 electrode 12 object to be measured

Claims (6)

A probe needle for measuring the electrical characteristics of the measurement object by bringing the tip into contact with the electrode of the measurement object,
A probe needle characterized in that protrusions made of a quadrangular pyramid or a triangular pyramid having a vertex angle of 35 degrees or more and 125 degrees or less are formed in a matrix at a pitch of 4 μm or more and 20 μm or less on the tip.   The probe needle according to claim 1, wherein at least the tip has at least one selected from gold plating, palladium plating, rhodium plating, and nickel plating.   The probe needle according to claim 1 or 2, wherein a portion other than the tip of the probe needle is covered with an insulating film. A probe needle manufacturing method for measuring the electrical characteristics of a measured object by bringing the tip into contact with an electrode of the measured object,
Preparing a metal conductor with an insulating coating having a predetermined length in which an insulating coating is formed on the outer periphery of the metal conductor;
A protrusion forming step of forming a protrusion made of a quadrangular pyramid or a triangular pyramid having a vertex angle of not less than 35 degrees and not more than 125 degrees in a matrix form at a pitch of not less than 4 μm and not more than 20 μm on at least one end of the metal conductor with an insulating coating;
Peeling the insulating coating at the tip of the pre-probe needle on which the protrusion is formed;
Forming a plating layer on the exposed portion from which the insulating coating has been peeled;
A method of manufacturing a probe needle, comprising:   5. The probe according to claim 4, wherein, in the protrusion forming step, the protrusion made of the quadrangular pyramid is performed by orthogonal biaxial V-groove processing, and the protrusion made of the triangular pyramid is performed by triaxial V-groove processing intersecting at 60 degrees. Needle manufacturing method.   In the preparation step, the metal conductor with an insulating coating is formed by continuously applying an insulating coating on the outer periphery of a long metal conductor to form a long conductor with an insulating coating; The method for manufacturing a probe needle according to claim 4, wherein the probe needle is prepared through a step of cutting.

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