probe unit

Abstract

The present application provides a probe unit, even if the contact engagement position of high-frequency circuit is offset, the free length of the contact is fixed, so that the electrode can be stably contacted, and the measurement quality is improved. The probe unit of the present application has: a coaxial connector mounted on the main body, which transmits and receives electrical signals between the tester via a coaxial cable; a high-frequency circuit connected with the coaxial connector to transmit electrical signals; a plurality of contacts, the top end of which electrically contacts the electrode of the inspected body, and transmits and receives electrical signals between the high-frequency circuit; and a base between the contact and the high-frequency circuit, the base is respectively provided on the contact in a manner that the free length of each contact becomes a specified length.

Description

TECHNICAL FIELD

[0001] The present application relates to a probe unit, for example, which can be used in an inspection device for inspecting electrical characteristics of a semiconductor integrated circuit. BACKGROUND

[0002] For example, in the case of inspecting 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.

[0004]

PRIOR ART DOCUMENTS

[0005]

PATENT DOCUMENTS

[0006]

Patent Document 1

[0007]

PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In addition, there is a variation in the height of the electrode pads of the object to be inspected. Therefore, the contact is provided as a cantilever type probe, and thus, the contact is elastically deformed by overdrive, so that the electrode pads can be contacted even if there is a variation in the height.

[0009] However, when the contact is joined to the high-frequency circuit, if the joining position of the contact is shifted, the free length of the cantilever type contact is changed, and thus, the magnitude of the pressure of the contact is varied. As a result, the contact does not well contact the electrode pad, and adversely affects the measurement quality.

[0010] Therefore, in view of the above problems, there is a need for a probe unit which can fix the free length of the contact even if the joining position of the contact to the high-frequency circuit is shifted, can stably contact the electrode, and can improve the measurement quality.

[0011]

MEANS OF SOLVING THE PROBLEMS

[0012] To solve the problem, the probe unit of the present application is characterized by comprising: a coaxial connector which is mounted to a main body portion, and transmits / receives an electric signal between a tester via a coaxial cable; a high-frequency circuit which is connected to the coaxial connector, and transmits an electric signal; a plurality of contacts whose tip portions electrically contact an electrode of an object to be inspected, and transmit / receive an electric signal between the high-frequency circuit; and a base which is interposed between the contacts and the high-frequency circuit, and is provided to the contacts so that the free length of each contact becomes a predetermined length.

[0013]

EFFECT OF THE INVENTION

[0014] According to the present application, the free length of the contact can be fixed, the electrode can be stably contacted, and thus the measurement quality can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a partial enlarged view of a part A in FIG. 1. Figure 2

[0016] Figure 2 is a whole configuration view showing the whole configuration of the probe unit of the first embodiment.

[0017] Figure 3 are a side view and a plan view of the engagement structure of the contact of the first embodiment.

[0018] Figure 4 are a side view and a plan view of the engagement structure of the conventional contact.

[0019] Figure 5 is an explanatory view for explaining a case where the conventional contact contacts the electrode terminal of the object to be inspected in the first embodiment.

[0020] Figure 6 are stress analysis diagrams of the model where the engagement position of the conventional contact is shifted and the overdrive.

[0021] Figure 7 is a graph showing the relationship between the stress generated on the conventional contact and the overdrive.

[0022] Figure 8 are stress analysis diagrams of the model where the engagement position of the contact of the first embodiment is shifted and the overdrive.

[0023] Figure 9 is a graph showing the relationship between the stress generated on the contact of the first embodiment and the overdrive.

[0024] Figure 10 are a partial enlarged view and a plan view of the contact equipped in the probe unit of the second embodiment. DETAILED DESCRIPTION

[0025] (A) First Embodiment

[0026] Hereinafter, the first embodiment of the probe unit of the present application will be described in detail with reference to the accompanying drawings.

[0027] (A-1) Configuration of the First Embodiment

[0028] Figure 2 is a whole configuration view showing the whole configuration of the probe unit of the first embodiment.

[0029] Figure 1 is a partial enlarged view of a part A in FIG. 1. Figure 2 ​enlarged view of a part of A in Fig. 1.

[0030] Figure 2 In the first embodiment, the probe unit 1 is provided with a main body 11, a coaxial connector 12, a high-frequency circuit 13, a plurality of contacts 14 (14a to 14c), and a plurality of bases 15.

[0031] Further, in the description of the common configuration of the contacts 14a to 14c and the like, the contacts 14 and the like are described, and in the description of the individual configuration, the contacts 14a and the like are described. The same applies to the description of other configuration elements.

[0032] The probe unit 1 is, for example, a high-frequency probe used when electric characteristics of a high-frequency circuit as an object to be inspected are inspected. The probe unit 1 is also called a probe head.

[0033] The example probe unit 1 is provided with three contacts 14 and is a GSG (Ground-Signal-Ground) type high-frequency probe, but is not limited thereto and can be applied to a GS type high-frequency probe provided with two contacts 14, a GSGS type high-frequency probe provided with four contacts 14, a GSSG type high-frequency probe, and the like provided with a high-speed transmission line.

[0034] The probe unit 1 is connected to a tester (not shown) side via a coaxial cable and is capable of electrically contacting an electrode terminal of an object to be inspected. For example, at the time of inspection, in the probe unit 1, the coaxial connector 12 inputs an electric signal from the tester, the high-frequency circuit 13 relays the electric signal to each of the contacts 14, and each of the contacts 14 supplies the electric signal to the electrode terminal of the object to be inspected which is electrically contacted. In addition, the probe unit 1 gives an electric signal output from the object to be inspected supplied with the electric signal to the tester. In this way, the tester is capable of inspecting electric characteristics of the object to be inspected.

[0035] The main body 11 has a base 111 and a support 112. In order to achieve that the tip end of each of the contacts 14 which is joined to the high-frequency circuit 13 can reliably electrically contact the electrode terminal of the object to be inspected, the support 112 of the main body 11 supports the coaxial connector 12 and the high-frequency circuit 13 obliquely.

[0036] The coaxial connector 12 is connected to a coaxial cable connected to the tester. For example, like Figure 2 As exemplified in the example of Fig. 1, the coaxial connector 12 is fixed to the fixing member in a state in which the posture thereof is inclined and is mounted on the support 112 of the main body 11.

[0037] The high-frequency circuit 13 is a circuit which relays an electric signal to the coaxial connector 12 and each of the contacts 14 and, for example, a semi-rigid coaxial cable can be used. One end of the high-frequency circuit 13 is connected to the coaxial connector 12, and the other end is joined to the plurality of contacts 14.

[0038] Further, in order to make the contact 14 horizontal, the other end portion of the high-frequency circuit 13 is cut to form a horizontal end surface (also referred to as "joint surface") 131. The high-frequency circuit 13 is joined to the plurality of contacts 14 on the end surface 131.

[0039] The contact 14 electrically contacts the electrode terminal of the object to be inspected, and is a ground (G) line or a signal (S) line of the high-frequency probe.

[0040] The contact 14 is formed of an electrically conductive material. One end portion of the contact 14 is joined to the base 15 to be joined to the end surface 131 of the high-frequency circuit 13 via the base 15, and the other end portion has a contact portion 16 that electrically contacts the electrode terminal of the object to be inspected on the lower surface side. Thus, the contact 14 is supported to the end surface 131 of the high-frequency circuit 13 via the base 15, and is a cantilever type probe (contact) having a fixed thickness. Further, the contact 14 is a substantially triangular shape in plan view, in which the thickness in the plate thickness direction is fixed, and the width in the long side direction becomes smaller as it goes to the object to be inspected side. Further, the shape of the contact 14 is not limited to this.

[0041] The contact portion 16 is a portion that electrically contacts the electrode terminal of the object to be inspected, and is formed of an electrically conductive material. In this embodiment, a case in which the contact portion 16 is a cylinder is exemplified, but the shape of the contact portion 16 is not limited to this, and can be a triangular pyramid, a prismatic pyramid, or the like.

[0042] The base 15 is a member interposed between the contact 14 and the end surface 131 of the high-frequency circuit 13, and is formed of an electrically conductive member such as a nickel alloy. The base 15 maintains the free length of the cantilever, that is, the contact 14, when the contact 14 is joined to the high-frequency circuit 13. The base 15 can also be said to be a free length adjustment member that adjusts the free length of the contact 14.

[0043] Further, the base 15 can make the mechanical physical quantity (for example, pressure, stress, shear force, moment of force, or the like) generated on each contact 14 when the contact 14 contacts the electrode terminal of the object to be inspected substantially the same among the plurality of contacts 14, so that stable contact can be achieved, and thus the measurement quality can be improved.

[0044] Further, the base 15 is provided for each contact 14. The base 15 is a member having a certain thickness, and the planar shape of the base 15 is not particularly limited, and can be rectangular, square, or the like.

[0045] Next, the joint structure of the contact 14 that is joined to the end surface 131 of the high-frequency circuit 13 will be described using the drawings.

[0046] Figure 3 (A) of FIG. 1 is a side view of the joint structure of the contact 14 of the first embodiment, Figure 3 (B) is a plan view. Figure 4(A) is a side view showing the conventional engagement structure of contact 94. Figure 4 (B) is a bottom view.

[0047] Figure 5 This is an explanatory diagram illustrating the situation when contacts 94a-94c contact electrode terminals 5a-5c of the object being inspected. Furthermore, Figure 5 In the above, the contact surface of the high-frequency circuit 93 that provides contact 94a to 94c is represented in an abstract way.

[0048] like Figure 4 (A) Figure 4 As illustrated in (B), in the past, the end face 931 of the high-frequency circuit 93 and the contact 94 were directly joined together by methods such as hard welding, ultrasonic bonding, resistance welding, and laser welding.

[0049] Contact 94 is a cantilevered probe supported on the end face 931 of the high-frequency circuit 93. Therefore, even in situations like... Figure 5 As illustrated in (A), if the height of the electrode terminal 5 of the inspected object deviates, the contact 94 will also elastically deform, so that the contact 94 can stably contact the electrode terminal 5 (see reference). Figure 5 (B)

[0050] For example, in the case of Figure 5 As shown in (B), when the height of electrode terminal 5b is higher than that of other electrode terminals 5a and 5c, it is known that when contact 94b is brought into contact with electrode terminal 5b, the pressure generated on contact 94b is stronger than that generated on other contacts 94a and 94c, and the elastic deformation of contact 94b is greater than that of other contacts 94a and 94c.

[0051] In addition, since the contact 94 is a fine structure made by MEMS (Micro Electro Mechanical Systems), when the high-frequency circuit 93 is connected to the contact 94, there is a situation where the connection is made at a position that deviates from the designed connection position.

[0052] When the engagement position of the contact 94 on the high-frequency circuit 93 shifts, the free length of the contact 94 changes, thus affecting the magnitude of the contact pressure generated on the contact 94. As a result, stable contact cannot be obtained with the electrode terminals of the object being inspected, which may adversely affect the measurement quality.

[0053] Therefore, in the first embodiment, the base 15 is configured such that even if the engagement position of the contact 14 with the high-frequency circuit 13 deviates from the design value, the free length of the contact 14 will become the design value.

[0054] like Figure 3As shown in (A), the base 15 is positioned between the high-frequency circuit 13 and the contact 14. Here, the free length of the contact 14 is designed such that when the contact 14 and the base 15 are joined, the length from the position of the end face 151 of the base 15 in the long side direction of the contact 14 to the position of the contact portion 16 becomes the designed free length.

[0055] In other words, the contact 14 and the base 15 are joined in such a way that the length from the end face 151 of the base 15 to the contact portion 16 is the designed value. Then, the base 15 provided on the contact 14 is joined to the end face 131 of the high-frequency circuit 13, thereby connecting the contact 14 to the high-frequency circuit 13.

[0056] Thus, by engaging the contact 14 through the dielectric base 15, the free length of the contact 14 can be maintained at the design value, so the pressure of the contact 14 can be controlled at a value close to the design value, thereby obtaining stable contact with the electrode terminal and improving the measurement quality.

[0057] Figure 6 (A) Figure 6 (C) shows the model of the offset of the engagement position between the high-frequency circuit 93 and the contact 94, and the stress analysis diagram under overdrive. Furthermore, Figure 6 In the stress analysis diagram, the contact surface of the high-frequency circuit 93 that provides contact 94 for engagement is also represented in an abstract way.

[0058] like Figure 6 As shown in (B), when the engagement position of contact 94 is not offset relative to the design value (e.g., engagement offset value = ±0 mm), the stress analysis diagram of contact 94 during operation shows that each of the three contacts 94 generates approximately the same level of pressure. Furthermore, the magnitude of the pressure on each contact 94 is also close to the design value (the designed pressure value).

[0059] Figure 6 (A) shows a stress analysis diagram when the engagement position of contact 94 is offset towards the -X direction relative to the design value (e.g., engagement offset value = -0.1 mm). In this case, the free length of contact 94 is shorter than the design value, so it is known that the pressure of each contact 94 during overdrive is greater than... Figure 6 The pressure (design pressure value) of each contact 94 of (B) is large.

[0060] Figure 6 Figure (C) shows the stress analysis diagram when the engagement position of contact 94 is offset towards the +X direction relative to the design value (e.g., engagement offset value = +0.1 mm). In this case, if... Figure 6 By comparing the magnitudes of the pressures at each contact 94 of (B), we can determine...Figure 6 The pressure ratio of each contact 94 of (C) Figure 6 The pressure (design pressure value) of each contact 94 of (B) is small.

[0061] like Figure 6 (A) Figure 7 (C) and Figure 8 As shown, the shift in the engagement position of contact 94 will cause a change in the free length of contact 94, which will affect the magnitude of the pressure on contact 94.

[0062] In contrast, Figure 8 (A) Figure 8 (C) is the engagement model and stress analysis diagram under overdrive when the base 15 with contact 14 is engaged to the high-frequency circuit 13 in the first embodiment.

[0063] exist Figure 8 In case (B), when the contact 14 with the base 15 is engaged to the high-frequency circuit 13, the engagement position of the contact 14 is not offset relative to the design value (for example, the engagement offset value = ±0 mm). In this case, the free length of the contact 14 is the design value, so the magnitude of the pressure generated on each contact 14 during overdrive becomes a value close to the design value.

[0064] In addition, in the like Figure 8 In cases like (A), where the engagement position of contact 14 is offset towards the -X direction relative to the design value (e.g., engagement offset value = -0.1mm), and like... Figure 9 In cases where the engagement position of contact 14 is offset in the +X direction relative to the design value (e.g., engagement offset value = +0.1mm), the free length of contact 14 remains unchanged, thus maintaining the design value.

[0065] Therefore, as Figure 3 As shown, regardless of the engagement position, the free length of each contact 14 remains consistent with the design, so the pressure generated on each contact 14 during overdrive becomes a value close to the design value. As a result, reliable and stable contact with the electrode terminals can be achieved, and the measurement quality is improved.

[0066] As described above, when the contact 14 is coupled to the high-frequency circuit 13, the free length of the contact 14 can be kept consistent with the design by means of the dielectric base 15.

[0067] Furthermore, the contact 14 and the base 15, and the base 15 and the high-frequency circuit 13 can be joined by methods such as hard soldering, ultrasonic bonding, resistance welding, and laser welding.

[0068] Further, the plurality of contacts 14 are respectively joined to the end surface 131 of the high frequency circuit 13, and at this time, design is performed so as to equalize the impedance on the high frequency circuit 13 side (output impedance) and the impedance on the plurality of contacts 14 side (input impedance).

[0069] For example, in order to prevent the generation of a standing wave caused by reflection which becomes an obstacle to transmission of a high frequency signal, design is performed so as to match the impedance values (for example, 50 Ω) of the input and output impedances. The characteristic impedance Z0 in the high frequency probe which transmits a high frequency signal has a characteristic shown in formula (1).

[0070] [Formula 1]

[0071]

[0072] In formula (1), C represents a capacitance (electrostatic capacitance), and L represents an inductance. The capacitance C is proportional to the dielectric constant εγand the line width, and is inversely proportional to the line interval.

[0073] In order to match the characteristic impedance, the thickness of the contacts 14 is made uniform and the "line width" is fixed. Further, in order to fix the "line interval", the contact 14a and the contact 14b are joined in such a manner that the gap between the contact 14a and the contact 14b becomes a value wl which is the designed gap length. Similarly, the contact 14b and the contact 14c are joined in such a manner that the gap between the contact 14b and the contact 14c becomes a value w2 which is the designed gap length.

[0074] Further, Figure 2 In (B) of the above, in the case of the contact 14a and the contact 14c which are ground (G) lines, the widths (lengths in the Y direction) of the bases 15a and 15c are larger than the widths of the contact 14a and the contact 14c. Further, in the case of the contact 14b which is a signal (S) line, the width of the base 15b is the same degree as the width of the contact 14b.

[0075] (A-2) Effects of the 1st embodiment

[0076] As described above, according to the 1st embodiment, the bases are provided on the contacts in such a manner that the lengths from the base end surface positions to the contact positions in the long side directions of the contacts become free lengths which are designed, and thus the high frequency circuit can be joined to the contacts without changing the free lengths of the contacts, and stable contact can be achieved, and the measurement quality is improved.

[0077] (B) 2nd embodiment

[0078] Next, the 2nd embodiment of the probe unit of the present application will be described in detail with reference to the drawings.

[0079] (B-1) Configuration of the 2nd embodiment

[0080] The probe unit of the second embodiment will be referred to as probe unit 1A, and the contact will be referred to as contact 24 and the like.

[0081] The basic configuration of the probe unit 1A of the second embodiment is the same as that of the probe unit 1 of the first embodiment. Figure 2 Thus, in the second embodiment, the explanation will be made using the explanation of the first embodiment. Figure 10

[0082] (A) of FIG. 1 1 is a partial enlarged view of the portion A of the probe unit 1A of the second embodiment, Figure 2 (B) of FIG. 1 1 is a bottom view of the portion A. Figure 10 Figure 10 The probe unit 1A of the second embodiment differs from the contact 14 of the first embodiment in the structure of the contact 24. Thus, in the second embodiment, the detailed explanation will be made focusing on the structure of the contact 24.

[0083] Further, as in the first embodiment, the probe unit 1A of the second embodiment is provided with the pedestal 15 per contact 24 and the contact 24 is joined with the high-frequency circuit 13 with the pedestal 15 interposed therebetween.

[0084] As shown in (A) of FIG. 1 1, the contact 24 (24a to 24c) is a ground line or a signal line of a high-frequency probe as in the first embodiment. In addition, the contact 24 is formed of an electrically conductive material and is formed in a uniform thickness. Further, the contact 24 is supported at the end surface 131 of the high-frequency circuit 13 via the pedestal 15.

[0085] As shown in (A) of FIG. 1 1, the contact 24 (24a to 24c) is a ground line or a signal line of a high-frequency probe as in the first embodiment. In addition, the contact 24 is formed of an electrically conductive material and is formed in a uniform thickness. Further, the contact 24 is supported at the end surface 131 of the high-frequency circuit 13 via the pedestal 15. Figure 10

[0086] The contact 24 is formed with a hole that penetrates in the thickness direction (a direction orthogonal to the arrangement direction of the respective contacts 24) in the central region, and this hole will also be referred to as a space domain 241.

[0087] Here, the reason for forming the space domain 241 on the contact 24 will be explained. The probe unit 1A is required to match the impedance with the high-frequency circuit 13. For example, in the first embodiment, the impedance is matched by making the thickness of the contact 14 uniform and fixing the air gap between the contact 14a (or the contact 14c) of the ground line and the contact 14b of the signal line.

[0088] However, the following situation is taken into consideration: if the probe design is made with the impedance matching as a priority, an adverse situation such as the pressure (for example, stress, shear force, torque of force, and the like) generated on the contact being too strong or the pressure being too weak can occur.

[0089] ​​Therefore, in the second embodiment, a spatial domain extending through the deformation direction of the contact 24 is formed, thereby adjusting the magnitude of the pressure generated on the contact 24 without changing the thickness of the signal line and the ground line (the thickness of the contact 24) and the length of the air gap between the signal line and the ground line (between the contacts 24).

[0090] The characteristic impedance Z0 has the characteristics shown in equation (1) above.

[0091] As mentioned above, in equation (1), the capacitance C is directly proportional to the dielectric constant εγ and the line width, and inversely proportional to the distance between the lines. In this way, the characteristic impedance Z0 converges to the capacitance C and the inductance L, and is affected by the electrical properties of the component material, the width of the contact 24, the thickness of the contact 24, and the proximity of the signal line and the ground line (the length of the air gap).

[0092] In this second embodiment, the thickness of the contact 24 is fixed, and the length of the air gap between the signal line and the ground line is also fixed. Therefore, the spatial domain 241 is configured such that the width of a portion of the contact 24 surrounding the spatial domain 241, namely the edge portion 242 and the edge portion 243, is fixed.

[0093] by Figure 10 The structure of contact 24a of (B) will be used as an example for explanation. The contact 24b of the signal line and the contact 24c of the grounding line have the same structure.

[0094] exist ​ In example (B), edge portions 242a and 243a are the two ends of the contact 24a, which is approximately triangular in shape when viewed from above, in the width direction (Y direction). In other words, edge portions 242a and 243a are located on opposite sides in the left-right direction (Y direction) separated by the spatial domain 241a. Furthermore, the width of edge portions 242a and 243a in the width direction is fixed within the free length.

[0095] Thus, by providing a spatial domain 241 on each contact 24, the pressure of each contact 24 can be adjusted and the impedance matched on the one hand, without changing the thickness of each contact 24 and the air gap between the signal line and the ground line.

[0096] (B-2) Effects of the second embodiment

[0097] As described above, according to the second embodiment, in addition to the effects explained in the first embodiment, the following effects are also achieved.

[0098] According to the second embodiment, a spatial domain is formed on the signal line and the ground line while keeping 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 fixed. On the one hand, the pressure generated on the contact during contact can be adjusted, and on the other hand, the impedance can be adjusted.

[0099] (C) Other Embodiments

[0100] The above-described first and second embodiments also mention various modified embodiments, and the present application can also employ the following modified embodiments.

[0101] (C-1) The first embodiment illustrates a case where the space domain 241 is a long hole having a substantially triangular shape according to the shape of the contact 24, but the shape of the space domain 241 is not limited thereto.

[0102] Further, two rows of space domains can also be arranged in the longitudinal direction of the contact 24, in which case the width of the edge portion of the contact present between the two rows of space domains is also fixed.

[0103] (C-2) The above-described embodiments illustrate a case where the contact has a substantially triangular shape in plan view, but the shape of the contact is not particularly limited.

[0104] (C-3) The above-described embodiments describe an example where the contact is joined to the base, but the contact and the base can also be formed in one piece by MEMS or the like.

[0105] Symbol Explanation

[0106] 1 and 1A... probe unit, 5 (5a to 5c)... electrode terminal, 11... main body portion, 111... base portion, 112... support portion, 12... coaxial connector, 13... high-frequency circuit, 131... end surface, 14 (14a to 14c) and 24 (24a to 24c)... contact, 15 (15a to 15c)... base, 151... end surface, 16... contact portion, 241... space domain, 242a... edge portion, 243a... edge portion.

Claims

1. A probe unit, characterized by, Possessing: a coaxial connector mounted to a main body portion, which transmits / receives electric signals between a tester via a coaxial cable; a high-frequency circuit connected to the coaxial connector to transmit electric signals; a plurality of contactors whose tip portions electrically contact electrodes of an object to be inspected, which transmit / receive electric signals with the high-frequency circuit; and a base interposed between the contactors and the high-frequency circuit, the base is a member different from the contactors and is a member having a certain thickness, the contactors are joined to one face of the base, and the high-frequency circuit is joined to the other face of the base, in one face of the base, the contactors are joined to the base in such a manner that the length from the end face of the base to the tip face of the contactors becomes a prescribed length.

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

3. The probe unit according to claim 1 or 2, wherein each of the contactors is formed with a space domain as a through hole, has a first edge portion and a second edge portion around the space domain, and the space domain is formed in such a manner that the widths of the first edge portion and the second edge portion become prescribed lengths.

4. The probe unit according to claim 1 or 2, wherein the plurality of contactors include contactors as signal lines and contactors as ground lines.

5. The probe unit according to claim 3, wherein the plurality of contactors include contactors as signal lines and contactors as ground lines. ​

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