Probe Unit

Abstract

To realize stable contact with an electrode and hence improve measurement quality by keeping free length of a contact to be constant even if a junction position of the contact with a high-frequency electric circuit deviates.SOLUTION: A probe unit includes: a coaxial connector that is mounted to a body part and transfers an electric signal between a tester and itself via a coaxial cable; a high-frequency electric circuit that is connected to the coaxial connector and transmits an electric signal; multiple contacts for transferring an electric signal between the high-frequency electric circuit and itself while the tip part is in electrical contact with an electrode of an inspected body; and a pedestal interposed between the contact and the high-frequency electric circuit. The pedestal is provided in each of the contacts such that the free length of the respective contacts becomes predetermined length.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a probe unit, and can be applied to, for example, a probe unit used in an inspection device that inspects electrical characteristics of a semiconductor integrated circuit. [Background technology]

[0002] For example, when inspecting the electrical characteristics of a high-frequency circuit, a high-frequency probe connected to a coaxial cable is used (see Patent Document 1).

[0003] The technology described in Patent Document 1 discloses the configuration of a high-frequency probe, and discloses that a hollow structure is provided between a signal line and a GND line. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-196821 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electrode pads of the test object vary in height, so by using a cantilever-type probe as the contactor, the contactor is elastically deformed by overdrive, making it possible to contact the electrode pads even if there is variation in height.

[0006] However, if the contactor is misaligned when it is joined to the high-frequency circuit, the free length of the cantilever-type contactor changes, causing the pressure of the contactor to vary. Teshi As a result, the contactor does not make good contact with the electrode pad, adversely affecting the quality of the measurement.

[0007] Therefore, in view of the above-mentioned problems, there is a demand for a probe unit that can keep the free length of the contactor constant even if the joining position of the contactor to the high-frequency circuit shifts, can make stable contact with the electrode, and can improve measurement quality. [Means for solving the problem]

[0008] In order to solve the above problems, the probe unit according to the present invention comprises a coaxial connector attached to a main body for transmitting and receiving electrical signals between the main body and a tester via a coaxial cable, a high-frequency circuit for transmitting electrical signals by connecting to the coaxial connector, and a plurality of contacts whose tips are in electrical contact with electrodes of a test object for transmitting and receiving electrical signals between the high-frequency circuit and the coaxial connector, Each and a base interposed between the contact and the high frequency circuit, Each contact is joined to the base so that the length from the end face of the base to the tip position of each contact is the specified length as designed. It is characterized by: Effect of the Invention

[0009] According to the present invention, the free length of the contact can be made constant, making it possible to stably contact the electrode, and improving the measurement quality. [Brief description of the drawings]

[0010] [Figure 1] FIG. 3 is a partially enlarged view of a portion A in FIG. [Diagram 2] FIG. 2 is an overall configuration diagram showing the overall configuration of a probe unit according to the first embodiment. [Diagram 3] 1A and 1B are a side view and a bottom view of a contact joining structure according to a first embodiment. [Figure 4] 1A and 1B are a side view and a bottom view of a conventional contact joining structure. [Diagram 5] FIG. 10 is an explanatory diagram for explaining a state in which a conventional contactor comes into contact with an electrode terminal of a device under test in the first embodiment. [Figure 6] This is a diagram showing a conventional model in which the contact joint position is shifted and a stress analysis diagram during overdrive. [Figure 7] FIG. 13 is a diagram showing the relationship between pressure and overdrive generated in a conventional contact. [Figure 8] 5A to 5C are diagrams illustrating a model in which the contact joint position of the first embodiment is shifted and a stress analysis diagram during overdrive. [Figure 9] 5A and 5B are diagrams illustrating the relationship between pressure generated in the contact and overdrive in the first embodiment. [Figure 10] 13A and 13B are a partial enlarged view and a bottom view of a contactor included in a probe unit of a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (A) First embodiment A first embodiment of a probe unit according to the present invention will be described in detail below with reference to the drawings.

[0012] (A-1) Configuration of the First Embodiment Fig. 2 is an overall configuration diagram showing the overall configuration of the probe unit according to the first embodiment. Fig. 1 is a partial enlarged view of a portion A in Fig. 2.

[0013] 2, the probe unit 1 according to the first embodiment includes a main body 11, a coaxial connector 12, a high-frequency electric circuit 13, a plurality of contacts 14 (14a to 14c), and a plurality of bases 15. As shown in FIG.

[0014] When describing the common configuration of the contacts 14a to 14c, etc., they will be described as contacts 14, etc., and when describing the individual configurations, they will be described as contacts 14a, etc. The same applies to the notations for the other components.

[0015] The probe unit 1 is, for example, a high-frequency probe used when inspecting electrical characteristics of a high-frequency circuit as an object to be inspected, and is also called a probe head.

[0016] The probe unit 1 has three contacts 14 and is shown as a high-frequency probe of the GSG (Ground-Signal-Ground) type, but is not limited to this and can also be applied to high-frequency probes with high-speed transmission lines, such as a GS type with two contacts 14, a GSGS type with four contacts 14, or a GSSG type.

[0017] The probe unit 1 is connected to a tester (not shown) via a coaxial cable and can be in electrical contact with the electrode terminals of the test subject. For example, during testing, the coaxial connector 12 of the probe unit 1 inputs an electrical signal from the tester, the high-frequency circuit 13 relays the electrical signal to each contact 14, and each contact 14 supplies the electrical signal to the electrode terminal of the test subject with which it is in electrical contact. The probe unit 1 also supplies the tester with an electrical signal output by the test subject to which the electrical signal has been supplied. In this way, the tester can test the electrical characteristics of the test subject.

[0018] The main body 11 has a base 111 and a support 112. The support 112 of the main body 11 supports the coaxial connector 12 and the high-frequency circuit 13 at an angle so that the tip of each contactor 14 joined to the high-frequency circuit 13 can reliably make electrical contact with an electrode terminal of the device under test.

[0019] The coaxial connector 12 is connected to a coaxial cable that is connected to a tester. For example, as shown in FIG. 2, the coaxial connector 12 is fixed to a fixture in a tilted state and attached to the support portion 112 of the main body 11.

[0020] The high-frequency electric circuit 13 is an electric circuit that relays an electric signal to the coaxial connector 12 and each contact 14, and may be, for example, a coaxial semi-rigid cable. One end of the high-frequency electric circuit 13 is connected to the coaxial connector 12, and the other end is joined to the multiple contacts 14.

[0021] In order to make the contacts 14 horizontal, the other end of the high-frequency electric circuit 13 is partially removed to form a horizontal end surface (also called a "joint surface") 131. The high-frequency electric circuit 13 has a plurality of contacts 14 joined to the end surface 131.

[0022] The contact 14 is for electrically contacting an electrode terminal of the device under test, and is a ground line or a signal line of the high frequency probe.

[0023] The contactor 14 is made of a conductive material. One end of the contactor 14 is joined to the base 15 and joined to the end face 131 of the high frequency electric circuit 13 via the base 15, and the other end has a contact portion 16 on the lower surface side that electrically contacts an electrode terminal of the test subject. In this way, the contactor 14 is supported by the end face 131 of the high frequency electric circuit 13 via the base 15, and is a cantilever type probe (contactor) with a constant thickness. The contactor 14 has a constant thickness in the plate thickness direction, a width that decreases toward the test subject in the longitudinal direction, and an approximately triangular shape in a plan view. The shape of the contactor 14 is not limited to this.

[0024] The contact portion 16 is a portion that electrically contacts the electrode terminal of the test object and is made of a conductive material. In this embodiment, the contact portion 16 is illustrated as being cylindrical, but the shape of the contact portion 16 is not limited thereto and may be a triangular pyramid, a pyramid, or the like.

[0025] The base 15 is a member interposed between the contactor 14 and the end surface 131 of the high-frequency electric circuit 13, and is made of a conductive member such as a nickel alloy. The base 15 maintains the free length of the contactor 14, which is a cantilever, when the contactor 14 is joined to the high-frequency electric circuit 13. The base 15 can also be said to be a free-length adjusting member that adjusts the free length of the contactor 14.

[0026] In addition, when the contactors 14 come into contact with the electrode terminals of the test object, the base 15 can make the mechanical physical quantities (e.g., pressure, stress, shear force, moment of force, etc.) generated in each contactor 14 approximately the same among multiple contactors 14, thereby ensuring stable contact and improving measurement quality.

[0027] The base 15 is provided for each contact 14. The base 15 is a member having a certain thickness, and the shape of the base 15 in a plan view is not particularly limited, but may be rectangular, square, or the like.

[0028] Next, the joining structure of the contact 14 joined to the end surface 131 of the high-frequency electric circuit 13 will be described with reference to the drawings.

[0029] 3A is a side view of the joint structure of the contact 14 according to the first embodiment, and FIG. (A) 4(A) is a side view showing the joint structure of a conventional contact 94, and FIG. 4(B) is a bottom view.

[0030] Fig. 5 is an explanatory diagram for explaining a state in which the contactors 94a to 94c come into contact with the electrode terminals 5a to 5c of the device under test. Note that in Fig. 5, the joint surfaces of the high-frequency circuit 93 to which the contactors 94a to 94c are joined are abstracted.

[0031] As shown in Figs. 4(A) and 4(B), conventionally, an end face 931 of a high-frequency electric circuit 93 and a contact 94 are directly joined by a method such as brazing, ultrasonic bonding, resistance welding, or laser welding.

[0032] The contactor 94 is a cantilever-type probe supported on an end surface 931 of the high-frequency electric circuit 93. Therefore, for example, as shown in FIG. 5A, even if there is variation in the height of the electrode terminal 5 of the test object, the contactor 94 elastically deforms, so that the contactor 94 stably contacts the electrode terminal 5. 5 (See FIG. 5(B)).

[0033] For example, as shown in FIG. 5(B), when the height of the electrode terminal 5b is higher than the other electrode terminals 5a, 5c, when the contactor 94b is brought into contact with the electrode terminal 5b, a stronger pressure is generated on the contactor 94b than on the other contactors 94a, 94c, and it can be seen that the elastic deformation of the contactor 94b is greater than the elastic deformation of the other contactors 94a, 94c.

[0034] Incidentally, since the contactor 94 has a microstructure produced by MEMS (Micro Electro Mechanical Systems) or the like, when the contactor 94 is joined to the high-frequency circuit 93, it may end up being joined at a position that is shifted from the designed joining position.

[0035] If the joining position of the contactor 94 in the high-frequency electric circuit 93 is misaligned, the free length of the contactor 94 changes, which affects the magnitude of the pressure generated at the time of contact in the contactor 94. As a result, stable contact with the electrode terminal of the test object cannot be obtained, which may adversely affect the measurement quality.

[0036] Therefore, in the first embodiment, the base 15 is provided so that the free length of the contactor 14 remains at the design value even if the joining position of the contactor 14 with respect to the high-frequency electric circuit 13 deviates from the design value.

[0037] 3(A), pedestal 15 is interposed between high-frequency electric circuit 13 and contactor 14. Here, the free length of contactor 14 is designed, and when contactor 14 and pedestal 15 are joined together, contactor 14 and pedestal 15 are joined together so that the length from the position of end face 151 of pedestal 15 to the position of contact portion 16 in the longitudinal direction of contactor 14 is the designed free length.

[0038] That is, contactor 14 and base 15 are joined so that the length from end face 151 of base 15 to contact portion 16 is a design value. Then, base 15 provided on contactor 14 is joined to end face 131 of high-frequency electric circuit 13, thereby joining contactor 14 to high-frequency electric circuit 13.

[0039] By joining the contactor 14 in this manner via the base 15, the free length of the contactor 14 can be maintained at the design value, and the pressure of the contactor 14 can be suppressed to a value close to the design value, thereby obtaining stable contact with the electrode terminal and improving measurement quality.

[0040] 6(A) to 6(C) are diagrams of stress analysis during overdrive for a model in which the joint position between high-frequency electric circuit 93 and contactor 94 is misaligned. Note that, even in the stress analysis diagram of FIG. 6, the joint surface of high-frequency electric circuit 93 to which contactor 94 is joined is depicted in an abstract manner.

[0041] 6(B), when there is no deviation in the joint position of the contacts 94 from the design value (for example, joint deviation value = ±0 mm), the stress analysis diagram of the contacts 94 during overdrive shows that approximately the same amount of pressure is generated in each of the three contacts 94. Also, the magnitude of the pressure of each contact 94 is close to the design value (designed pressure value).

[0042] Fig. 6(A) shows a stress analysis diagram when the joint position of the contactor 94 is shifted in the -X direction from the design value (for example, joint misalignment value = -0.1 mm). In this case, since the free length of the contactor 94 is shorter than the design value, it can be seen that the pressure of each contactor 94 during overdrive is larger than the magnitude of the pressure of each contactor 94 in Fig. 6(B) (design pressure value).

[0043] Fig. 6(C) shows a stress analysis diagram when the joint position of the contactor 94 is shifted in the +X direction from the design value (for example, joint misalignment value = +0.1 mm). In this case, when comparing the magnitude of pressure of each contactor 94 in Fig. 6(B), it is found that the magnitude of pressure of each contactor 94 in Fig. 6(C) is smaller than the magnitude of pressure of each contactor 94 in Fig. 6(B) (design pressure value).

[0044] As shown in FIGS. 6(A) to 6(C) and 7, if the joining position of the contactor 94 is shifted, the free length of the contactor 94 changes, which affects the magnitude of the pressure of the contactor 94.

[0045] In contrast, FIGS. 8(A) to 8(C) are diagrams showing a joint model in which base 15 having contact 14 provided thereon is joined to high-frequency electric circuit 13 in the first embodiment, and stress analysis diagrams during overdrive.

[0046] 8(B), when the contactor 14 with the base 15 is joined to the high-frequency circuit 13, the joining position of the contactor 14 does not deviate from the design value (for example, the value of the joining deviation = ±0 mm). In this case, since the free length of the contactor 14 is the design value, the magnitude of the pressure generated in each contactor 14 during overdrive is close to the design value.

[0047] In addition, as shown in FIG. 8A, when the joint position of the contactor 14 is shifted in the −X direction from the design value (for example, the value of the joint deviation = −0.1 mm), as shown in FIG. 8C, when the joint position of the contactor 14 is shifted in the +X direction from the design value (for example, the value of the joint deviation = +0.1 Even if the length is increased by 1 mm, the free length of the contact 14 does not change and the design value can be maintained.

[0048] Therefore, as shown in Fig. 9, the free length of each contact 14 can be maintained as designed regardless of the joining position, so the magnitude of pressure generated in each contact 14 during overdrive is close to the design value. As a result, reliable and stable contact with the electrode terminal is possible, and measurement quality is improved.

[0049] As described above, by interposing the base 15 when joining the contact 14 to the high-frequency electric circuit 13, the free length of the contact 14 can be maintained as designed.

[0050] The contact 14 and the base 15, and the base 15 and the high-frequency circuit 13 can be joined by using techniques such as brazing, ultrasonic bonding, resistance welding, and laser welding.

[0051] In addition, each of the multiple contactors 14 is joined to the end face 131 of the high-frequency electric circuit 13, and is designed to make the impedance (output impedance) on the high-frequency electric circuit 13 side equal to the impedance (input impedance) on the multiple contactors 14 side.

[0052] For example, in order to prevent the occurrence of standing waves due to reflections that impede the transmission of high-frequency signals, designs are made to match the impedance values ​​of the input and output impedances (e.g., 50 Ω). The characteristic impedance Z0 of a high-frequency probe that transmits high-frequency signals has the characteristics expressed by formula (1).

[0053]

number

[0054] In order to match the characteristic impedance, the thickness of the contact 14 is made uniform to make the "line width" constant. Furthermore, in order to make the "line spacing" constant, the contact 14a and the contact 14b are joined so that the gap between the contact 14a and the contact 14b is the designed gap length value w1. Similarly, the contact 14b and the contact 14c are joined so that the gap between the contact 14b and the contact 14c is the designed gap length value w2.

[0055] 3B, for contacts 14a and 14c which are ground lines, the widths (lengths in the Y direction) of bases 15a and 15c are made larger than the widths of contacts 14a and 14c. For contact 14b which is a signal line, the width of base 15b is made approximately the same as the width of contact 14b.

[0056] (A-2) Effects of the First Embodiment As described above, according to the first embodiment, by providing a base on the contactor so that the length from the base end face position to the contact portion position in the longitudinal direction of the contactor is a designed free length, the contactor can be joined to the high-frequency circuit without changing the free length of the contactor, enabling stable contact and improving measurement quality.

[0057] (B) Second embodiment Next, a second embodiment of the probe unit according to the present invention will be described in detail with reference to the drawings.

[0058] (B-1) Configuration of the second embodiment The probe unit according to the second embodiment is referred to as a probe unit 1A, and the contacts are referred to as contacts 24 and the like.

[0059] The basic configuration of a probe unit 1A of the second embodiment is the same as the configuration of the probe unit 1 of the first embodiment shown in Fig. 2. Therefore, the second embodiment will also be described using Fig. 2 of the first embodiment.

[0060] 10A is a partially enlarged view of a portion A of a probe unit 1A according to the second embodiment in FIG. 2, and FIG. 10B is a bottom view of portion A. As shown in FIG.

[0061] In the probe unit 1A of the second embodiment, the structure of the contactor 24 is different from that of the contactor 14 of the first embodiment. Therefore, in the second embodiment, the structure of the contactor 24 will be mainly described in detail.

[0062] In the probe unit 1A of the second embodiment, similarly to the first embodiment, a base 15 is provided for each contact 24, and the high-frequency electric circuit 13 and the contact 24 are joined with the base 15 interposed between them.

[0063] 10(A), the contacts 24 (24a to 24c) are ground lines or signal lines of the high-frequency probe, similar to the first embodiment. The contacts 24 are made of a conductive material and have a uniform thickness. The contacts 24 are supported on an end surface 131 of the high-frequency circuit 13 via a base 15.

[0064] The contact 24 has a hole formed in the central region that penetrates in the thickness direction (the direction perpendicular to the arrangement direction of the contacts 24 ).

[0065] Here, the reason for forming the space 241 in the contactor 24 will be described. The probe unit 1A needs to match the impedance with the high-frequency electric circuit 13. For example, in the first embodiment, the thickness of the contactor 14 is made uniform, Ground Impedance is matched by making the air gap between the line contact 14a (or contact 14c) and the signal line contact 14b constant.

[0066] However, if the probe is designed with priority given to impedance matching, problems may occur such as the pressure (e.g., stress, shear force, moment of force, etc.) acting on the contact being too strong or too weak.

[0067] Therefore, in the second embodiment, a spatial area is formed that penetrates the contactor 24 in the deformation direction, and the magnitude of the pressure generated in the contactor 24 is adjusted without changing the thickness of the signal line and the ground line (the thickness of the contactor 24) and the length of the air gap between the signal line and the ground line (between the contactors 24).

[0068] Special The electrochemical impedance Z0 has the characteristics expressed by the above-mentioned formula (1).

[0069] As described above, in formula (1), the capacitance C is proportional to the dielectric constant εγ and the line width, and inversely proportional to the line spacing. Then, the characteristic impedance Z0 converges to the capacitance C and inductance L, and is affected by the electrical properties of the component materials, the width and length of the contact 24, the thickness of the contact 24, and the proximity of the signal line and the ground line (the air gap length).

[0070] In this case, in the second embodiment, the thickness of the contact 24 is constant, and the length of the air gap between the signal line and the ground line is also constant. Therefore, the space 241 is provided so that the widths of the edges 242 and 243, which are parts of the contact 24 surrounding the space 241, are constant.

[0071] The structure of the contact 24a in Fig. 10(B) will be described as an example. The signal line contact 24b and the ground line contact 24c also have the same structure.

[0072] 10B, the edge 242a and the edge 243a are both ends in the width direction (Y direction) of the contact 24a that is substantially triangular in plan view. In other words, the edge 242a and the edge 243a are located on both sides in the left and right direction (Y direction) of the space region 241a. The width lengths of the edge 242a and the edge 243a in the width direction are constant in the free length.

[0073] In this way, by providing a space area 241 in each contact 24, it is possible to match impedance while adjusting the pressure of each contact 24 without changing the thickness of each contact 24 and the air gap between the signal line and the ground line.

[0074] (B-2) Effects of the Second Embodiment As described above, according to the second embodiment, in addition to the effects described in the first embodiment, the following effects are achieved.

[0075] According to the second embodiment, while keeping constant the thickness of the signal line and the ground line and the length of the air gap between the signal line and the ground line, a spatial area is formed between the signal line and the ground line, and the impedance can be adjusted while adjusting the pressure generated on the contacts when they make contact.

[0076] (C) Other embodiments Although various modified embodiments have been mentioned in the first and second embodiments described above, the following modified embodiments can also be applied to the present invention.

[0077] (C-1) In the second embodiment, the spatial region 241 is an elongated hole having a substantially triangular shape in accordance with the shape of the contact 24, but the shape of the spatial region 241 is not limited to this.

[0078] Also, two rows of space regions may be arranged along the longitudinal direction of the contact 24, and in this case too, the edge of the contact existing between the two rows of space regions has a constant width.

[0079] (C-2) In the above embodiment, the contacts are illustrated as having a substantially triangular shape in a plan view, but the shape of the contacts is not particularly limited.

[0080] (C-3) In the above-described embodiment, an example was described in which the pedestal was joined to the contact, but the contact and the pedestal may be formed integrally using MEMS or the like. [Explanation of symbols]

[0081] 1 and 1A...probe unit, 5 (5a to 5c)...electrode terminal, 11...main body, 111...base, 112...support, 12...coaxial connector, 13...high-frequency circuit, 131...end surface, 14 (14a to 14c) and 24 (24a to 24c)...contactor, 15 (15a to 15c)...base, 151...end surface, 16...contact portion, 241...spatial area, 242a...edge, 243a...edge.

Claims

1. a coaxial connector attached to the main body for transmitting and receiving electrical signals between the main body and the tester via a coaxial cable; a high-frequency circuit that is connected to the coaxial connector and transmits an electrical signal; a plurality of contacts, each having a tip portion that electrically contacts an electrode of an object to be inspected and that transmits and receives an electric signal between the contacts and the high-frequency electric circuit; a base interposed between each of the contacts and the high frequency circuit; Equipped with Each of the contacts is joined to the base so that the length from the end face of the base to the tip position of each of the contacts is a predetermined designed length. A probe unit comprising:

2. 2. The probe unit according to claim 1, wherein each of said contacts is a cantilever type contact.

3. 2. The probe unit according to claim 1, wherein each of the contacts is integrally formed with the base.

4. Each of the contacts has a space area that is a through hole and has a first edge and a second edge around the space area; The spatial region is formed so that the width of the first edge portion and the width of the second edge portion are a predetermined length. The probe unit according to any one of claims 1 to 3.

5. 5. The probe unit according to claim 1, wherein the plurality of contacts include a contact serving as a signal line and a contact serving as a ground line.

Images