JP2005127891A - Inductor loaded inspecting probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductor loaded inspecting probe capable of accurately inspecting, without being mutually influenced by RF signals or giving noise to other terminals via the probe which connects a power supply for bias, when inspecting electrical characteristics, by contacting a probe to a device for high frequency or high speed. <P>SOLUTION: Electrode terminals 1 are formed at both ends of a pipe 2, and at least one side of the electrode terminals 1 is formed with mobile pins 11, 12 provided so that the projection length which projects from the end of the pipe can be made variable. An inductor 3 (31) is connected in series, in between the electrode terminals 1, provided at both ends of the pipe 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a semiconductor device in which a probe is directly connected to a terminal of a semiconductor device and a power source and a signal are supplied from the outside without soldering a discrete device such as a transistor or a diode, or a semiconductor device such as an IC to a mounting substrate. The present invention relates to a probe that supplies a bias power source when inspecting the above. More specifically, for signal high frequency and high speed (analog and high frequency are called high frequency, digital and very small pulse width and pulse interval are high speed, the same applies hereinafter, both collectively referred to as RF) The present invention relates to an inductor loaded inspection probe for inspecting a semiconductor device in which the RF signal does not leak to the power supply line side and affect other terminals as noise.

  For example, when inspecting RF devices such as semiconductor wafers, ICs or discrete semiconductor devices, a direct current inspection and an inspection in actual use are performed. In the inspection in actual use, a probe such as a probe card is used. Inspection is performed by bringing a needle (probe) into contact with each electrode terminal of the device to be inspected and applying a signal, power, or the like from the inspection apparatus via the probe needle. In this case, if the lead or the like is exposed, it is easy to pick up noise at that portion. Therefore, as shown in FIG. 8A, for example, as shown in FIG. A configuration is known in which each electrode terminal 101 to 103 of the device under test 100 is connected via an inspection jig having a probe 94 and a grounding probe 95 (see, for example, Patent Document 1).

  With such an inspection jig, the RF signal is connected to the RF signal probe 93 via the coaxial cable 97, and a gap is formed between the device under test 100 and the thin presser plate 98 on the metal block 91 due to the contraction of the spring. In addition, the signal is input and output by ensuring contact between the RF signal probe 93 and the electrode terminal of the device under test 100 by a spring, so that noise is not picked up as much as possible. . In FIG. 8A, reference numeral 96 denotes a wiring board made of a printed board or the like and forming the input side power supply wiring.

On the other hand, when the electrode terminal of the device under test is the inspection of the transistor Q as shown in FIG. 8B, for example, the bias power source V _B1 and the bias power source V _B2 are connected to the base terminal B and the collector terminal C of the transistor Q. are connected via the probe P, the input terminal iN which is provided via the capacitor C ₁ to the base terminal B, signals such as RF signal is input through the probe P, the amplified signal is, the capacitor from the collector C by the output terminal OUT which is output via the C ₂ to evaluate is taken out through the probe P, the inspection of the device under test is made. In this case, if an RF signal or the like input to the base B leaks to the bias power supply V _B1 side, it interferes with the output side of the collector and cannot be accurately inspected. Therefore, as shown in FIG. Choke coils L ₁ and L ₂ are inserted between P and the power source so that the RF signal does not leak to the power source side.

In the case of an inspected device having many electrode terminals such as an IC, as shown in FIG. 8A, an inductor 961 is provided on the circuit board 96 and connected in series after the probe. In FIG. 8B, R ₁ is a bias resistor connected between the base and the ground, R ₂ and C ₃ are connected in parallel, and a current feedback resistor and a bypass capacitor connected between the emitter and the ground. It is.
JP 2001-99889 A

  As described above, when inspecting the RF device, the probe connected to the electrode terminal to which the bias power supply is connected is connected via the choke coil, so that the RF signal interferes via the power supply side. It has been done to prevent. However, with the recent miniaturization of devices and RF, the electrode terminals are arranged very close to each other, and RF signals interfere with each other through a space even if they are not directly connected by wiring or the like. Therefore, the signal on the input side goes around to the output side through the probe connected to the device under test for inspection, or the wiring or circuit board connected to the probe, or it is sent to other terminals as noise There is a problem in that it may have an influence or an accurate inspection cannot be performed.

  The present invention has been made to solve such a problem, and when a probe is brought into contact with a high-frequency / high-speed semiconductor device to inspect the electrical characteristics, the probe is connected to a bias power source. It is an object of the present invention to provide an inductor loaded inspection probe that can perform an accurate inspection without causing RF signals to affect each other or causing noise to other terminals.

  Another object of the present invention is to form an inductor in the contact probe while providing a spring property by using a contact probe and connecting it to the electrode terminal of the device to be inspected. An object of the present invention is to provide a specific structure capable of blocking a signal.

  An inspection probe of an inductor loading type according to the present invention is provided on a pipe, a spring provided in the pipe, and both ends of the pipe, at least one of which can vary a protruding length protruding from an end of the pipe. Thus, the electrode terminal is a movable pin that is biased by the spring, and the inductor is connected in series between the electrode terminals provided on both ends of the pipe.

  Here, the movable pin means a pin whose tip can move along the axial direction such that the tip of the pin is contracted by the spring or the like when held and pressed by the spring or the like.

  The pipe may be formed of an insulating pipe, and the inductor may be formed of a coil shared with the spring. In this way, the inductor and the spring can be shared, and the number of parts can be reduced.

  A magnetic core is inserted into at least a part of the coil, a chip inductor is inserted in series between the electrode terminal and the coil or in the middle of the coil, or at least a part of the electrode terminal is a chip type By using an inductor, the inductance can be further increased. Here, the magnetic core means a material having a large relative permeability inserted into the coil.

  Further, the pipe is made of an insulating pipe, and the protrusion length of the movable pin is variable by providing the spring via an insulator between the electrode terminals, and a coil is provided on the outer peripheral side of the insulating pipe. It can also be provided that the inductor is formed by providing both ends thereof so as to be respectively connected to electrode terminals provided at both ends of the insulating pipe.

  A capacitor is formed by utilizing at least a part of the length of the pipe or by further providing an insulating cylinder on the outer periphery of the pipe, and a capacitor is formed between the electrode terminal and the ground. You can also

  With this configuration, the inductor is connected in the immediate vicinity of the tip of the inspection probe that contacts the electrode terminal of the device under test. Therefore, even if an RF signal is input to the device under inspection, the RF signal is inspected. Does not leak to the bias power source through the probe. Therefore, noise does not enter the device under test via the inspection probe, the wiring connected to the inspection probe, the circuit board connected between the power supply, the power supply, etc. Further, even if RF noise enters from the power supply or the circuit board side, it can be blocked by the inductor, and a very stable inspection can be performed. In addition, since the inductor can be loaded without increasing the thickness of the conventional inspection probe, the outer diameter can be reduced to about 1 mm and the device to be inspected, such as a conventional inspection jig for IC measurement. The present invention can be applied as it is even when the interval between the electrode terminals is narrow.

  Further, by using the insulating pipe or forming the capacitor on the outer periphery thereof, the RF noise mixed from the power source side can be efficiently removed by the capacitor. That is, if the RF noise has a sufficiently high frequency, it can be blocked by the inductor, but the low frequency noise that cannot be blocked by the inductor cannot be sufficiently blocked. If it is easy to input to the bias power supply and noise is input to the bias power supply, accurate inspection cannot be performed. However, since the capacitor is inserted between the bias power source probe and the ground, noise can be easily bypassed and removed. As a result, it is possible not only to prevent the cause of noise due to the RF signal leaking to the outside but also to remove noise in a wide frequency band that may enter from the outside.

  Next, the inductor loaded inspection probe of the present invention will be described with reference to the drawings. An inductor loaded inspection probe according to the present invention is provided with electrode terminals 1 (11, 12) at both ends of a pipe 2 as shown in FIG. At least one of them is formed by movable pins 11 and 12 urged by a spring 31 so that the protruding length protruding from the end of the pipe 2 can be made variable. An inductor 3 (31) is connected in series between the electrode terminals 1 provided on both ends of the pipe 2. In the example shown in FIG. 1, a coil spring 31 in which a spring that biases the movable pin and an inductor are shared is provided.

  The electrode terminal 1 is provided at both ends of the probe (pipe) so as to contact both the inspection apparatus side and the device under test side, and at least one of them ensures contact with the electrode terminal of the device under test. The tip end portion is expanded and contracted so that the protruding length is variable. In the example shown in FIG. 1, both end portions are formed at the sharp ends 11 a and 12 a, the sharp ends 11 a and 12 a protrude from both ends of the pipe 2, and the movable length is provided so that the protruding length is variable. It is formed by pins (plungers) 11 and 12. However, it is not necessary that both electrode terminals 1 are movable pins, and only one of them may be a movable pin depending on the application. That is, one of them may be a structure that is fixed to a circuit board or the like by being soldered without being a movable pin. As shown in FIG. 1, the movable pins 11, 12 are provided so that one end thereof is a sharp end 11 a, 12 a and the other end is formed on a base part 11 b, 12 b so that it can slide in the pipe 2. In order to prevent the movable pins 11 and 12 from coming out of the pipe 2, the base portions 11 b and 12 b are stopped by the bush 4 or the like at the end of the pipe 2.

  The sharp ends 11a and 12a are sharply formed so as to easily come into contact with the electrode terminals of the device to be inspected. However, it may be a curved surface such as a convex surface or a flat surface. Further, the bottom surfaces of the base portions 11b and 12b are flat surfaces, and are structured to be joined to a coil spring 31 or an end portion of the spring described later. Then, due to the spring property of the coil spring 31 to be described later, the base parts 11b and 12b are pressed until they hit the bush 4 so that the sharp ends 11a and 12a protrude from the end of the insulating pipe 21, and the When the sharp ends 11a, 12a are pressed, the sharp ends 11a, 12a are contracted, and the sharp ends 11a, 12a and the electrode terminals of the device to be inspected are completely in contact with each other by the force of the spring.

  The pipe 2 holds both the electrode terminals 1 at regular intervals, and when it is necessary to electrically insulate and hold the two electrode terminals 1, the two electrode terminals 1 are electrically connected by an insulating pipe. When it is not necessary to insulate, the metal pipe may be used. In the example shown in FIG. 1, the pipe 2 is constituted by an insulating pipe 21 in order to use a coil spring 31 provided between both electrode terminals 1 as a current path. As the insulating pipe 21, for example, resins such as polyimide and polycarbonate, and tubes such as ceramics can be used. As long as the distance between the electrode terminals 1 provided at both ends can be held so as not to exceed a certain distance, there is no problem even if the electrode terminals 1 are bent slightly, and mechanical strength like that of a conventional metal pipe is not necessarily required. In the case of a metal pipe, it can be formed of a copper / nickel alloy pipe, for example.

  The thickness of the pipe 2 is determined by the terminal interval of the device to be inspected. If the terminal interval is about several mm or more with a discrete element, an outer diameter of 1 mm or more can be used. If the element is small, the outer diameter needs to be about 1 mm or less. If the wall thickness is about 0.1 to 0.2 mm, the mechanical strength for holding the electrode terminal 1 can be obtained. In addition, the length of other signal probes, etc., becomes too long, so that the inductance becomes large and an accurate inspection cannot be performed. Therefore, when considering the length of the probe, it is preferably about 10 mm or less.

  In the example shown in FIG. 1, the inductor 3 includes a coil spring 31. The coil spring 31 forms an inductance and also acts as a spring that presses the movable pins 11 and 12 outward. In other words, if it functions only as an inductor, the coil may be formed without gaps, and a thin wire material such as copper having a low resistance can be used. However, in order to provide a function as a spring, A gap between the coil elements that can be shrunk is required, and a material having a spring property, for example, an iron-based material such as a piano wire or a stainless steel wire is required. Therefore, in order to form a thin and short inspection probe, if an inductor and a spring are shared, a sufficiently large inductance may not be formed due to size restrictions. In addition, when the electrical resistance is increased by using an iron-based material, it is necessary to perform plating such as gold plating on the surface.

The inductance L (unit: H) of the cylindrical coil is as follows. The Nagaoka coefficient is K, the magnetic permeability in the coil is μ, the number of turns of the coil is n, the cross-sectional area of the coil is S, and the axial length of the coil is a. ,
L = K ・ μ ・ n ²・ S / a
It is known to be given in That is, in order to make the inductance as large as possible, it is preferable that the number of turns n of the coil is large and the cross-sectional area is large. However, as described above, the overall length of the probe is preferably about 10 mm or less. In order to reduce the overall probe thickness to about 1 mmφ or less, assuming that the terminal spacing for inspecting tools and miniaturized transistors is small, the outer diameter of the coil spring 31 needs to be about 0.5 mmφ. There is.

  If a coil with a thickness of about 0.1 mmφ and a coil with an outer diameter of about 0.5 mmφ is formed, about 30 turns can be formed, and an inductance of about 40 nH can be obtained. Even an inductance of this level can be cut off if it is an RF signal of about 1 GHz or more. However, if an attempt is made to cut off a signal of about 50 MHz, for example, an inductance of about 1 μH is required and a winding number of about 150 turns is required. The Therefore, it is necessary to further increase the inductance as in an example in which a ferrite core is inserted into a coil to be described later, a chip inductor is connected in series, or the inductor and the spring are formed of different members. In addition, the function as a spring should just have the spring property which the sharp end of the above-mentioned movable pins 11 and 12 protrudes from the edge part of the pipe 2, and becomes depressed if it pushes.

  As described above, the bush 4 is provided when the pipe 2 is formed of an insulating resin or the like and cannot be caulked. The movable pins 11 and 12 are connected to the insulating pipe 21. The stoppers of the base portions 11b and 12b of the movable pins 11 and 12 are used so as not to come out. When the pipe 2 is made of metal, the movable pins 11 and 12 can be prevented from popping out by caulking without providing a bush. The bush 4 is a ring-shaped member having an inner diameter which is smaller than the diameter of the base portions 11b and 12b of the movable pins 11 and 12 and through which the sharp end portions 11a and 12a can pass. It can be used as a stopper for the movable pins 11 and 12 by being fixed to each other with an adhesive or the like. Therefore, the bush 4 may be a conductive material or an insulating resin as long as it has mechanical strength.

  With this configuration, the coil spring 31 and the spring that pushes the sharp ends 11a and 12a of the movable pins 11 and 12 outward from the end of the pipe 2 and the inductor 3 are shared, so the number of parts is small. Therefore, the inductor 3 can be loaded on the inspection probe at a very low cost.

  FIG. 2 is a modification of FIG. 1 in which the shape of the bush 4 is changed. That is, in the example shown in FIG. 2, the bush 4 is fixed to the outer periphery of both ends of the insulating pipe 21, and the bush 4 enters the inner peripheral side of the insulating pipe 21 on the end side of the insulating pipe 21. It is formed by bending. As a result, the bush 4 is securely fixed, and the length for fixing the bush 4 in the insulating pipe 21 is not required. Therefore, the number of turns of the inductor 3 can be increased correspondingly. The bush 4 may be either an insulating material or a conductive material, as in the above example, and the other parts are the same as in the example shown in FIG. 1, and the same parts are denoted by the same reference numerals. The description is omitted.

  FIG. 3 is a cross-sectional explanatory view showing another embodiment of the present invention. In this example, a magnetic core 32 made of a high permeability material such as ferrite or permalloy is inserted into a part of the inner periphery of the coil spring 31. 3 is constituted. As shown in the above equation (1), the inductance L increases as the magnetic permeability μ in the coil increases. Therefore, as described above, when the probe is thin and there is a dimensional restriction that cannot be made long, the inductance 32 can be reduced even by a small dimension by inserting the magnetic core 32 having a high magnetic permeability in the inner periphery of the coil spring 31. Can be bigger. For example, the relative permeability of ferrite is 1000 to 30000, which is much larger than the permeability of air, and the coil spring 31 also acts as a spring. Therefore, the magnetic core 32 cannot be put in the entire length of the coil spring 31 in an extended state. Even if the coil spring 31 is inserted about 2/3 of the length of the coil spring 31 in the extended state, the inductance can be increased to about 1000 times. The magnetic core 32 may be inserted into the coil spring 31 in a free state. However, if the magnetic core 32 is fixed to the base portion 12b of one movable pin 12, the magnetic core 32 can move even if the coil spring 31 expands or contracts. There is no hindrance to the function of the spring.

  The material of the magnetic core is not limited to the above-mentioned example, and supermalloy, amorphous alloy, sendust, pure iron, etc. can be used, but it is necessary to be electrically insulated from the coil spring 31. The other parts of the example shown in FIG. 3 are the same as the example shown in FIG. 1, and the same parts are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 4 is a similar cross-sectional explanatory view showing still another embodiment of the present invention. In this example, a chip type inductor 33 is inserted between the base portion 12 b of one movable pin 12 and the coil spring 31. The chip type inductor 33 is manufactured by, for example, laminated ceramics, and can form a coil by stacking very thin layers, and can make a small and large inductance. For example, an inductance of about 2 μH can be obtained with a chip type inductor having a 0.8 mm square and a thickness of about 1.6 mm. In this case, since a large inductance is obtained by the chip type inductor 33, it is not necessary to expect much of the inductance by the coil spring 31. Therefore, the coil pitch and the like can be set so that the function as a spring is sufficiently achieved. However, inductance also appears in the coil spring 31 portion, and the inductance can be further increased by inserting a magnetic core as shown in FIG. The other parts are the same as those in the previous examples, and the same parts as those in FIG.

  FIG. 5 expects only the action of the inductor 3 as the chip-type inductor 33 and the coil as the spring 5 as a spring for urging the movable pins 11 and 12. In this example, a chip type inductor 33 is shown inserted in the middle of the movable pin 12. Therefore, the pipe 2 does not need to be insulative, and in the example shown in FIG. 5, the spring 5 and the movable pins 11 and 12 are inserted into both ends of the metal pipe 22 as in the conventional contact probe. Both ends of the pipe 22 are used as stoppers for the base portions 11b and 12b of the movable pins 11 and 12 by caulking. However, as described above, an insulating pipe may be used as the pipe 2 and the chip inductor 33 may be inserted between the movable pin and the coil or between the coils. In this case, the spring 5 also functions as a coil and generates inductance.

  Since the chip-type inductor 33 is used in this way, a large inductance can be obtained in a small space, and it is not necessary to expect the inductance by the spring 5. Therefore, if the spring is formed so as to obtain a necessary spring property. In general, the electrical characteristics of the inductance and the mechanical characteristics of the spring characteristic can be formed to have desired characteristics by using separate components. In addition, since the spring 5 may be electrically short-circuited, the outer periphery can be constituted by the metal pipe 22, and the stoppers of the movable pins 11 and 12 can be constituted only by caulking of the metal pipe 22. Instead of inserting the chip inductor 33 in the middle of the movable pin 12, the entire electrode terminal 1 (11, 12) can be formed by a chip inductor. When the chip inductor 33 is inserted into the pipe 2, it is necessary to use an insulating pipe instead of a metal pipe.

  In the example shown in FIG. 6, as in the example shown in FIG. 5, the spring function for moving the electrode terminal (movable pins 11, 12) and the coil as the inductor are configured by different parts. This is another example. That is, in this example, the pipe into which the spring 5 and the movable pins 11 and 12 are inserted is constituted by the insulating pipe 21 as in the example shown in FIG. 1, and the coil 34 serving as the inductor 3 is formed on the outer periphery thereof. . As a result, the spring 5 may be formed so as to satisfy only the mechanical characteristics, and the coil 34 may be designed so as to satisfy only the electrical characteristics so as to obtain a desired inductance. As shown in FIG. 6, the insulator 6 is interposed between the movable pins 11 and 12 and the spring 5, because all the current between the electrodes 1 flows through the coil 34, thereby increasing the inductance. Is preferable. Although the insulator 6 is provided at both ends in FIG. 6, if it is provided only at one end, the current can be interrupted, so that the object can be achieved.

  With this configuration, since the coil 34 can be formed on the outer periphery of the insulating pipe 21, the outer diameter can be formed as large as about 0.8 mm and the spring property is not required. If the wire) is used, the number of turns can be greatly increased by dense winding. As a result, even an RF signal having a relatively low frequency can be sufficiently blocked. In this example, since the movable pins 11 and 12 at both ends need to be electrically connected via the coil 34, the bushes 41 at both ends of the insulating pipe 21 are formed of a metal material, and the coil 34. And the movable pins 11 and 12 are electrically connected by the metal bush 41 and also function as a stopper for the movable pins 11 and 12.

  Fig.7 (a) is the same cross-sectional explanatory drawing which shows other embodiment of this invention. In this example, a coil spring 31 is interposed as the inductor 3 between the movable pins 11 and 12, and a feedthrough capacitor (a capacitor 7 connected between the movable pins 11 and 12 and the ground) is connected in parallel with the probe. It is characterized by being. That is, a part of the insulating pipe 21 is thinned at the outer periphery to form a thin part 21a, and the metal tube 71 is inserted into the outer peripheral part to form one electrode, and the thin part 21a of the insulating pipe 21 is formed. On the inner periphery, a conductor part 72 having a long base portion of the movable pin 11 is formed, so that the other electrode of the capacitor 7 is formed, and the thin part 21a of the insulating pipe 21 is formed as a dielectric film. Has been. As a result, as shown in an equivalent circuit diagram in FIG. 7B, the inductor 3 is connected in series to the probe (movable pins 11 and 12), and the capacitor 7 is connected between the probe and the ground. Yes.

  With this configuration, it is possible not only to prevent the RF signal from leaking through the contact probe by the inductor 3, but also to remove noise entering from the outside such as a power source even at a relatively low frequency. It is possible to prevent intrusion to the device under test side, and it is possible to perform a very stable inspection by removing noise in a wide band. In FIG. 7A, the inductor and the capacitor are formed side by side in the vertical direction, but both may be formed side by side (concentrically). That is, a capacitor can be formed on the outer periphery with the structure shown in FIG. 1 or the like, or a capacitor can be formed on the inner side of the insulating pipe 21 or on the outer periphery of the coil 34 with the structure shown in FIG. it can.

  The present invention can be used when a probe is brought into contact with a semiconductor device such as a transistor or an IC, in particular, an RF device, and inspection similar to mounting is performed without soldering.

It is a section explanatory view showing one embodiment of the inspection probe by the present invention. FIG. 8 is a cross-sectional explanatory view showing a modification of the inspection probe shown in FIG. 1. It is a section explanatory view showing other embodiments of the inspection probe by the present invention. It is a section explanatory view showing other embodiments of the inspection probe by the present invention. FIG. 5 is an explanatory cross-sectional view showing a modification of FIG. It is a section explanatory view showing other embodiments of the inspection probe by the present invention. It is a section explanatory view showing other embodiments of the inspection probe by the present invention. It is a figure which shows the structural example of the inspection jig | tool of the conventional high frequency and high speed device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode terminal 2 Pipe 3 Inductor 5 Spring 7 Capacitor 11, 12 Movable pin 21 Insulating pipe 22 Metal pipe 31 Coil spring 32 Magnetic core 33 Chip type inductor 34 Coil

Claims (6)

  A pipe, a spring provided in the pipe, and a movable pin that is provided at both ends of the pipe and at least one of which is urged by the spring so that a protruding length protruding from an end of the pipe can be made variable. An inductor-loaded inspection probe comprising an electrode terminal and an inductor connected in series between the electrode terminals provided on both ends of the pipe.   The inspection probe according to claim 1, wherein the pipe is an insulating pipe, and the inductor is a coil shared with the spring.   The inspection probe according to claim 2, wherein a magnetic core is inserted into at least a part of the coil.   4. The inspection probe according to claim 1, wherein a chip inductor is inserted in series between the electrode terminal and the coil or in the middle of the coil, or at least a part of the electrode terminal is formed of a chip inductor. .   The pipe is made of an insulating pipe, and the spring is provided between the electrode terminals via an insulator so that the projecting length of the movable pin can be made variable. The inspection probe according to claim 1, wherein the inductor is formed by providing a portion so as to be connected to electrode terminals provided at both ends of the insulating pipe.   A capacitor is formed by utilizing at least a part of the length of the pipe or by further providing an insulating cylinder on the outer periphery of the pipe, and the capacitor is formed between the electrode terminal and ground. Item 6. The inspection probe according to any one of Items 1 to 5.

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