Probe structure and inspection device

Abstract

To enable matching of characteristic impedance at connection terminals as signal circuit relay points. [Solution] The present invention relates to a probe structure that transmits and receives high-frequency signals to an object under test via a contact portion that electrically contacts the electrodes of the object under test, and is characterized by comprising: a main body; a substrate holding member having a wiring board on one side and fixed to the main body on the other side; a connector joined to the wiring board of the substrate holding member and connecting the wiring of the wiring board to a coaxial cable via a connection terminal; and an impedance adjustment portion that adjusts the gap with the connection terminal to perform impedance matching.

Description

Technical Field

[0001] The present invention relates to a probe structure and an inspection apparatus, and can be applied to, for example, a probe structure and an inspection apparatus used for inspecting electrical characteristics of high-frequency devices such as semiconductor integrated circuits.

Background Art

[0002] For example, when inspecting the electrical characteristics of a semiconductor integrated circuit on a semiconductor wafer, a prober apparatus for aligning probes is used. In particular, in order to inspect the electrical characteristics of a high-frequency device, a high-frequency probe for transmitting and receiving a high-frequency signal to and from the high-frequency device is used.

[0003] FIG. 2 is a configuration diagram of a probe structure used for inspecting a conventional high-frequency test object.

[0004] In FIG. 2, a conventional probe structure 90 includes a lower ground plate 91, a probe substrate 92, a mounting portion 93, a coaxial connector 95, and an upper ground plate 99. The probe structure 90 is assembled by screwing a screw 96 into a mounting through hole 93a and a screw hole 91a. When a coaxial cable connected to the coaxial connector 95 contacts a contact pad (also referred to as an "input / output signal terminal") 951, an electrically connected state is achieved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when there is a member connected to the ground (GND) near the input / output signal terminal, the characteristic impedance may decrease at the input / output signal terminal, which may affect high-frequency measurement.

[0007] Therefore, in view of the above-mentioned problems, the present invention aims to provide a probe structure and inspection device that can achieve characteristic impedance matching at connection terminals as signal path relay points. [Means for solving the problem]

[0008] To solve these problems, the first invention provides a probe structure for exchanging high-frequency signals with an object under test via a contact portion that electrically contacts the electrodes of the object under test, characterized in that it comprises a main body, a substrate holding member having a wiring board on one side and fixed to the main body on the other side, a connector joined to the wiring board of the substrate holding member and connecting the wiring of the wiring board to a coaxial cable via a connection terminal, and an impedance adjustment portion that adjusts the gap with the connection terminal to match the impedance.

[0009] The second aspect of the present invention relates to an inspection device for inspecting the electrical characteristics of an object under inspection using a high-frequency signal, and is characterized in that it comprises a probe structure that electrically contacts an electrode of the object under inspection with a contact portion to exchange a high-frequency signal with the object under inspection, wherein the probe structure is the probe structure of the first aspect of the present invention. [Effects of the Invention]

[0010] According to the present invention, characteristic impedance matching can be achieved at connection terminals that serve as signal path relay points. [Brief explanation of the drawing]

[0011] [Figure 1] This is a configuration diagram showing the external appearance of an electrical contact according to the embodiment. [Figure 2] This is a diagram illustrating the configuration of a probe structure mounted on a conventional high-frequency probe device. [Figure 3] This is an explanatory diagram illustrating the connection structure of a conventional probe structure. [Figure 4] This is an overall configuration diagram showing the overall configuration of the semiconductor inspection apparatus according to the embodiment. [Figure 5] It is an explanatory diagram for explaining the connection configuration of the electrical contact according to the embodiment. [Figure 6] It is a diagram showing a transmission line equivalent circuit and the impedance at a conventional input / output signal terminal. [Figure 7] It is a diagram showing the impedance of the input / output signal terminal before and after adjustment in the embodiment. [Figure 8] It is a diagram showing the return loss waveforms before and after impedance adjustment in the embodiment.

Embodiment for Carrying out the Invention

[0012] (A) Embodiment Hereinafter, embodiments of the probe structure and the inspection apparatus according to the present invention will be described in detail with reference to the drawings.

[0013] In this embodiment, as an example of the inspection apparatus according to the present invention, a case of applying it to a semiconductor inspection apparatus for inspecting the electrical characteristics of high-frequency devices on a semiconductor wafer is illustrated.

[0014] Also, as an example of the probe structure according to the present invention, a case of applying it to a high-frequency probe structure mounted on a semiconductor inspection apparatus is illustrated.

[0015] Note that the probe structure and the inspection apparatus according to the present invention are not limited to the high-frequency probe structure and the semiconductor inspection apparatus of the embodiment.

[0016] (A-1) Configuration of the Semiconductor Inspection Apparatus FIG. 4 is an overall configuration diagram showing the overall configuration of the semiconductor inspection apparatus according to the embodiment.

[0017] Note that although each figure shows the main components, it is not limited to the components shown, and actually includes components not shown. In each figure, the same or corresponding components are labeled with the same or corresponding reference numerals. Each figure is a schematic diagram, and it should be noted that the dimensions, thicknesses, etc. of each component are different from the actual ones. Also, the dimensions and ratios of corresponding components are different between the drawings. The embodiments shown below illustrate devices and methods for embodying the technical idea of the present invention, and do not limit the materials, shapes, structures, arrangements, etc. of the components of the present invention.

[0018] In FIG. 4, the X-direction, Y-direction, and Z-direction are defined. In FIG. 4, the X-direction (first direction) is the left-right direction of the paper surface, the Y-direction (second direction) is the depth direction of the paper surface, and the Z-direction (third direction) is the up-down direction of the paper surface.

[0019] In FIG. 4, the semiconductor inspection apparatus 1 according to the embodiment includes a base portion 2, a frame portion 3, a test object 4, a moving device 5, a mounting table 6, a top plate 7, a manipulator 8, a high-frequency probe structure mounting portion 9, and a high-frequency probe structure 10.

[0020] Note that the semiconductor inspection apparatus 1 is not limited to the configuration shown in FIG. 4. For example, it can also be applied to a prober that does not have the base portion 2 and the frame portion 3, or a prober having simple members instead of the base portion 2 and the frame portion 3. Also, it may be provided with a microscope, a laser cutter device, etc.

[0021] The semiconductor inspection apparatus 1 uses a high-frequency device (semiconductor integrated circuit) formed on a semiconductor wafer as the test object 4, and electrically contacts a contact portion (also referred to as a "contactor" or "contact pin") 14 with the electrode terminals of the test object 4 to inspect the electrical characteristics of the test object 4. The semiconductor inspection apparatus 1 is also called a prober.

[0022] During testing, the semiconductor testing apparatus 1 electrically contacts the contact portion 14 of the high-frequency probe structure 10 with the electrode terminals of the object under test 4. The semiconductor testing apparatus 1 then applies a high-frequency signal to the object under test 4 via the contact portion 14 and acquires the signal in response from the object under test 4 via the contact portion 14. In this way, the electrical characteristics of the high-frequency device are tested. For example, the semiconductor testing apparatus 1 tests the electrical characteristics of a high-frequency device using a high-frequency signal from a coaxial cable.

[0023] The mounting platform 6 is used to place semiconductor chips, wafers, or other objects to be inspected 4. The mounting platform 6 may also have a temperature control function to adjust the temperature of the objects to be inspected 4 to a high or low temperature.

[0024] The moving device 5 moves the mounting table 6 on which the object to be inspected 4 is placed, thereby positioning the electrode terminals of the object to be inspected 4 and the contact portion 14. For example, the moving device 5 has an X-axis moving unit that moves the mounting table 6 in the X-axis direction, a Y-axis moving unit that moves it in the Y-axis direction, a Z-axis moving unit that moves it in the Z-axis direction, and a θ-axis moving unit that rotates it in the θ-axis direction, enabling movement in the X, Y, Z, and θ axes. Note that the moving device 5 is not limited to moving in four axes.

[0025] The high-frequency probe structure 10 includes a contact portion 14 that electrically contacts the electrode of the object under test, and exchanges high-frequency signals with the object under test 4 via the contact portion 14. In this example, a case in which two high-frequency probe structures 10 are provided is illustrated.

[0026] The high-frequency probe structure 10 is attached to the high-frequency probe structure mounting portion 9 of the manipulator 8 and is also connected to a coaxial cable. The manipulator 8 is operated to align the contact portion 14 with the electrode of the object under inspection.

[0027] The manipulator 8 is mounted on the top plate 7 and aligns the high-frequency probe structure 10. The manipulator 8 may be manually operated by an operator or it may be automatically controlled.

[0028] (A-2) High-frequency probe structure Figure 1 is a diagram showing the external configuration of the high-frequency probe structure 10 according to the embodiment.

[0029] In Figure 1, the high-frequency probe structure 10 according to the embodiment includes a body portion 11 as the main body, an FPC holder 12 as a substrate holding member, an FPC 13 as a wiring board, a contact portion 14, connectors 15A and 15B, and impedance adjustment portions 16A and 16B.

[0030] The body portion 11 is the main component that forms the base of the high-frequency probe structure 10. The body portion 11 is a plate member made of metal such as iron, and has a bent structure formed by bending. The bent body portion 11 has a first plate portion 111 and a second plate portion 112.

[0031] The first plate portion 111 of the body portion 11 is the part that is attached to the high-frequency probe structure mounting portion 9. For attachment to the high-frequency probe structure mounting portion 9, the first plate portion 111 has three arranged holes 111a and one hole 111b.

[0032] The second plate portion 112 of the body portion 11 is the part that electrically connects the coaxial cable, which can be connected via connectors 15A and 15B, to the wiring pattern of the FPC 13 held by the FPC holder 12.

[0033] The second plate portion 112 is provided with an elongated hole, and the first support portion (the portion where the contact portion 14 is provided) 121 of the bent FPC holder 12 is inserted into the elongated hole and set. As a result, the first support portion 121 of the bent FPC holder 12 is inserted through the elongated hole of the body portion 11 and holds the FPC holder 12.

[0034] Furthermore, with the FPC holder 12 inserted and set in the body portion 11, the first surface 112a of the second plate portion 112 and the second support portion 122 of the FPC holder 12 are overlapped, and connectors 15A and 15B are placed on top and fixed. This allows the FPC holder 12 to be sandwiched and fixed between the first surface 112a of the second plate portion 112 of the body portion 11 and the connectors 15A and 15B. Since the FPC holder 12 holds the FPC 13 made of a soft material, the connectors 15A and 15B are pressed against the FPC 13 and joined by contact pressure. Other fixing methods may also be applied.

[0035] Connectors 15A and 15B are for connecting to the coaxial cable.

[0036] The FPC13 has a wiring pattern formed on a flexible substrate and is provided on the first surface 12a of the FPC holder 12. The wiring pattern of the FPC13 is connected to the contact portion 14. As will be described later, when the connectors 15A and 16B are fixed, the input / output signal terminal 151 is connected to the wiring pattern on the FPC13, and the coaxial cable and the wiring pattern on the FPC13 can be connected via the input / output signal terminal 151.

[0037] The FPC holder 12 holds the FPC 13 and is a plate member formed from a material such as stainless steel. The FPC holder 12 has a bent structure that is bent at approximately a right angle by a bending process. The FPC 13 is bonded to the first surface 12a of the FPC holder 12 to hold the FPC 13 and support the contact portion 14.

[0038] The bent FPC holder 12 has a first support portion 121 and a second support portion 122.

[0039] The first support portion 121 of the FPC holder 12 is a member that supports the contact portion 14 at its tip. The first support portion 121 has a roughly triangular base portion 121a whose width (length in the Y-axis direction) decreases from the body portion 11 side to the tip side, an alignment portion 121c which is the tip of the base portion 121a and aligns the contact portion 14, and an elongated portion 121b between the base portion 121a and the alignment portion 121c.

[0040] The base portion 121a is roughly triangular in shape to facilitate alignment of the contact portion 14 with respect to the electrode terminals of the object under inspection 4. Similarly, the alignment portion 121c is rectangular (roughly rectangular) in shape as shown in Figure 1. Normally, inspection is performed using two high-frequency probe structures 10, and aligning the rectangular ends of a pair of alignment portions 121c to each other serves as a guide for alignment, making it easier to align the contact portion 14.

[0041] The second support portion 122 of the FPC holder 12 is the side that is fixed to the body portion 11. The second support portion 122 is fixed to the body portion 11, supports the first support portion 121, and is the component that connects the input / output signal terminals 151 of connectors 15A and 15B to the FPC 13.

[0042] The impedance adjustment sections 16A and 16B adjust the decrease in impedance that occurs near the input / output signal terminal 151, which serves as a connection terminal.

[0043] The detailed configuration of the impedance adjustment units 16A and 16B will be described later, but for example, they adjust the distance between the input / output signal terminal 151 and the impedance adjustment unit 16 to match the impedance. The impedance adjustment units 16A and 16B have a rod-shaped member (for example, a screw) with an end face at the tip, and they adjust the distance between this rod-shaped member and the input / output signal terminal 151. The impedance adjustment units 16A and 16B are also connected to ground (GND).

[0044] For example, the FPC holder 12 is provided with an adjustment hole 20 for adjusting the impedance. The body portion 11 is also provided with a through hole 115 for inserting impedance adjustment parts 16A and 16B, which are screws. By adjusting the distance between the impedance adjustment parts 16A and 16B inserted into the through hole 115 and the input / output signal terminal 151, impedance matching can be achieved.

[0045] The impedance adjustment sections 16A and 16B are provided for each of the connectors 15A and 15B.

[0046] Figure 5 is an explanatory diagram illustrating the connection configuration of the high-frequency probe structure 10 according to the embodiment.

[0047] The connection configurations of connectors 15A and 15B are basically the same. Here, to explain the common configuration of connectors 15A and 15B, they will be referred to as "connector 15" and "impedance adjustment unit 16".

[0048] The FPC holder 12, body section 11, and connector 15 are electrically connected to ground. The impedance adjustment section 16 is also electrically connected to ground via the body section 11.

[0049] In Figure 5, the body portion 11 is provided with a through hole 115, and the impedance adjustment unit 16 is inserted through the through hole 115 of the body portion 11. The impedance adjustment unit 16 can be pushed and pulled within the through hole 115.

[0050] Furthermore, the impedance adjustment section 16 may be equipped with a biasing member 17 such as a coil spring to prevent loosening. When pushed towards the body section 11, the impedance adjustment section 16 can move toward the body section 11 while receiving biasing force.

[0051] In the FPC holder 12, an adjustment hole 20 is provided at a position corresponding to the through hole 115 of the body portion 11. This allows the tip portion 161 of the impedance adjustment portion 16, which is inserted through the through hole 115 of the body portion 11, to reach the adjustment hole 20. Here, the tip of the impedance adjustment portion 16 is cut off, resulting in a flat cross-section. In other words, the tip portion 161 is a cut surface. This makes it easier to adjust the size of the space in the adjustment hole 20.

[0052] The adjustment hole 20 penetrates the FPC holder 12 but not the FPC 13. Therefore, the adjustment hole 20 is a space enclosed by the FPC 13, the body portion 11, the wall surface of the FPC holder 12, and the tip portion 161 of the impedance adjustment portion 16. The size of the space in the adjustment hole 20 is variable depending on the position of the push-pull impedance adjustment portion 16. By changing the size of this space in the adjustment hole 20, the impedance can be adjusted.

[0053] Here, we will explain the decrease in characteristic impedance at the input / output signal terminal 151 of the high-frequency probe structure 10.

[0054] In the high-frequency probe structure 10, the contact portion 14 is connected to the input / output signal terminal 151 of the high-frequency signal. At this time, the design must be such that the impedance of the high-frequency circuit side (output impedance) and the impedance of the contact portion 14 (input impedance) are equal.

[0055] Conventionally, as illustrated in Figure 3, there is an FPC holder and body section (corresponding to the probe board 92 and lower ground plate 91 in Figure 3) electrically connected to ground opposite the input / output signal terminal 951. As a result, the characteristic impedance at the input / output signal terminal 951 drops, affecting high-frequency measurements.

[0056] For example, in order to prevent the generation of standing waves due to reflections that interfere with the transmission of high-frequency signals, the design is such that the impedance values ​​of the input and output impedances (e.g., 50Ω) are matched. The characteristic impedance Z0 of a high-frequency probe that transmits high-frequency signals is expressed by equation (1).

number

[0057] In equation (1), C represents capacitance and L represents impedance. The characteristic impedance Z0 is proportional to L and inversely proportional to C.

[0058] Figure 6(A) is the transmission line equivalent circuit. At input / output signal terminal 951, the FPC holder and body (corresponding to the probe board 92 and lower ground plate 91 in Figure 3) are located near the input / output signal terminal 951, so the capacitance C is large, and the characteristic impedance Z0 becomes small (see Z in Figure 6(B)).

[0059] In view of the problems of the conventional technology described above, in this embodiment, as illustrated in Figure 5, an adjustment hole 20 is provided in the FPC holder 12 to increase the distance between the input / output signal terminals 151 and the FPC holder 12 and body portion 11. Furthermore, an impedance adjustment unit 16 is provided to change the size of the space of the adjustment hole 20. In other words, the gap between the input / output signal terminals 151 and the impedance adjustment unit 16 is changed. This makes it possible to reduce the capacitance C and adjust the magnitude of the characteristic impedance Z0.

[0060] Figure 7 shows the impedance at the input / output signal terminal 151 before and after adjustment by the impedance adjustment unit 16 of the embodiment.

[0061] Before adjustment, with the impedance adjustment unit 16 not yet set, an adjustment hole 20 is provided in the FPC holder 12 and a through hole 115 is provided in the body 11 by tapping, so that the capacitance C value is low. The central axis of the through hole 115 and the central axis of the input / output signal terminal 151 are aligned coaxially (P axis in Figure 5). In this case, as shown in Figure 7, the impedance Z0 value becomes large.

[0062] Subsequently, the impedance adjustment unit 16 can obtain a GND signal from the through hole 115 of the body unit 11, and adjusts the magnitude of the impedance Z0 by pushing and pulling the impedance adjustment unit 16, which acts as a screw.

[0063] For example, by pushing the impedance adjustment unit 16 into the through hole 115 and narrowing the distance between the input / output signal terminal 151 and the impedance adjustment unit 16, the capacitance C value increases, and the impedance value of the input / output impedance can be designed to (for example, 50Ω) as shown in Figure 7.

[0064] Figure 8 shows the return loss waveforms before and after impedance adjustment in the embodiment.

[0065] When dealing with high-frequency signals, all impedances should be matched during design to minimize reflection. For example, if the input and output impedances are designed to be 50Ω, and there is a point in the signal path where the impedance changes, some of the signal will not reach the receiver but will instead return to the transmitter; this phenomenon is called reflection.

[0066] As shown in Figure 8, comparing the return loss before and after adjustment, we can see that the reflection is reduced after adjustment compared to before adjustment, indicating that the characteristics have been improved.

[0067] (A-3) Effects of the Embodiment As described above, according to this embodiment, the impedance adjustment unit, which can be pushed and pulled through the through-hole in the body, adjusts the gap with the input and output signal terminals, thereby achieving characteristic impedance matching at the connection terminals as signal path relay points.

[0068] (B) Other embodiments Although various modified embodiments have been mentioned in the embodiments described above, the present invention can also be applied to the following modified embodiments.

[0069] (B-1) In the embodiments described above, the example shown is that the high-frequency probe structure has two connectors, but the method can also be applied to cases where it has one or three or more connectors. In that case as well, the connection structure at each connector will be the same as the connection structure described in the embodiments described above, and the same effect will be obtained.

[0070] (B-2) Generally, impedance matching in circuits using high-frequency signals requires precise control of the connection structure. However, in this embodiment, a rod-shaped member such as an adjustment screw can be pushed and pulled, allowing impedance to be controlled with a simple structure. While it is desirable for the central axis of the input / output signal terminal and the axis of the impedance adjustment section to be the same axis, impedance can be adjusted without perfectly aligning the axes. [Explanation of Symbols]

[0071] 1...Semiconductor inspection device, 2...Base unit, 3...Frame unit, 4...Object to be inspected, 5...Moving device, 6...Mounting platform, 7...Top plate, 8...Manipulator, 9...Probe block mounting unit, 10...High-frequency probe structure, 11...Body part, 111...First plate part of the body part, 111a and 111b...Hole parts, 112...Second plate part of the body part, 112a...First surface of the second plate part of the body part, 115...Through hole, 12...FPC holder, 12a...First surface of the FPC holder, 121...First support part of the FPC holder, 121b...Base part of the FPC holder, 121c...Alignment part of the FPC holder, 122...Second support part of the FPC holder, 13...FPC, 14...Contact part, 15 (15A and 15B)... Connector, 151... Input / Output signal terminal, 16 (16A and 16B)...Impedance adjustment section, 161...Tip of impedance adjustment section, 17...Biasing member, 20...Adjustment hole, 90...Probe structure, 91...Body part, 92...FPC holder, 93...FPC, 94...Contact part, 951...Input / output signal terminal.

Claims

1. In a probe structure that exchanges high-frequency signals with an object under test via a contact portion that electrically contacts the electrode of the object under test, The main body and A circuit board holder member is provided on one side and fixed to the main body on the other side, A connector is joined to the wiring board of the substrate holding member and connects the wiring of the wiring board and a coaxial cable via a connection terminal, An impedance adjustment unit adjusts the gap with the aforementioned connection terminal to match the impedance. A probe structure characterized by comprising the following features.

2. The substrate holding member provides space around the connection terminals, The main body portion is provided with through holes at positions corresponding to the space provided in the substrate holding member, The impedance adjustment unit has a rod-shaped member that can be pushed and pulled through the through hole in the main body, and adjusts the gap between the connection terminal and the rod-shaped member. The probe structure according to claim 1.

3. The probe structure according to claim 1, characterized in that the substrate holding member, the main body, the connector, and the impedance adjustment unit are connected to ground.

4. The probe structure according to claim 1, characterized in that the tip of the rod-shaped member of the impedance adjustment section is an end face.

5. The probe structure according to claim 1, characterized in that the wiring substrate of the substrate holding member is a flexible substrate.

6. In an inspection device that uses high-frequency signals to inspect the electrical characteristics of an object under inspection, The probe structure comprises a contact portion that electrically contacts the electrodes of the object to be inspected, and transmits and receives high-frequency signals between the probe structure and the object to be inspected. The probe structure is the probe structure according to any one of claims 1 to 5. An inspection device characterized by the following features.

Images