TWI572865B - Probe card - Google Patents

Description

Probe card

The invention relates to a probe card.

In recent years, with the increase in the speed of semiconductor devices, various countermeasures have been proposed for securing excellent high-frequency characteristics in probe cards. For example, the wiring of the probe card is a coaxial line, and the coaxial line is designed to have a predetermined value of impedance (for example, 50 Ω).

In the related art, a probe card is disclosed in Japanese Laid-Open Patent Publication No. 2010-139479, which is provided with a substrate having a plurality of connecting portions on the board surface and a plurality of grounding connection portions; a first probe; a fixing resin portion disposed on a surface of the substrate and fixed to an intermediate portion of the first probe; and a conductor plate disposed between the connecting portion and the fixing resin portion And the region is connected to the grounding connection portion and disposed between the grounding connection portions; and the coaxial wire is provided with the center conductor and the outer conductor, and one end of the center conductor is on the region of the conductor plate and the first probe The needle is joined such that the other end of the center conductor is joined to the first of the plurality of connecting portions, and one end of the outer conductor is joined to the conductor plate.

Figure 7 is a diagram showing a probe card 9 of the prior art. As previously mentioned, the coaxial line 26 is designed to have a predetermined value of impedance. One end of the coaxial line 26 is connected to the probe 28, and the other end is connected to the contact portion 22 disposed on the front surface side through the connection wiring 25 provided in the substrate 24. Connection wiring 25 is made to have electrical conductivity The metal wiring is formed, and measures such as providing the ground wiring to the surroundings are applied so as to have a predetermined value (for example, 50 Ω) in the connection wiring 25. Further, the ground wiring is grounded to a zero volt potential (ground potential), and has a shielding effect of isolating noise from the outside.

From the viewpoint of the workability at the time of manufacture, etc., the connection wiring 25 is an unnecessary wiring, and a so-called stub 25s may be formed, and it is difficult to be in a short line for 25 s from the viewpoint of workability and the like. A grounding wire is placed around it. Therefore, due to the existence of the short line 25s, the impedance between the connection wiring 25 and the coaxial line 26 is mismatched, which may adversely affect the high frequency characteristics of the probe card 9.

It is an object of the present invention to provide a probe card that ensures excellent high frequency characteristics.

The probe card of the present invention includes a substrate, a contact portion for contacting the detecting device is disposed on the first plate surface, a probe is in contact with the detected portion detected by the detecting device, and the fixing portion is disposed on the substrate a second plate surface opposite to the first plate surface of the substrate, and an intermediate portion of the probe; and a coaxial wire having a center conductor and an outer conductor, wherein one end of the center conductor is connected to the probe The other end of the center conductor is directly connected to the contact portion.

Further, in the probe card of the present invention, the substrate preferably has a groove portion and a through hole portion, and the groove portion is formed in a region where the support portion for supporting the substrate is disposed, and is disposed on the front coaxial line. a groove of the region; and the through hole portion is formed with a through hole through which the coaxial line directly connected to the contact portion penetrates in a region where the groove portion is provided.

Further, in the probe card of the present invention, the substrate preferably has a through hole portion provided in a region other than a region where the support portion for supporting the substrate is disposed, and is formed to be directly connected to a through hole through which the aforementioned coaxial line of the contact portion penetrates.

Further, in the probe card of the present invention, it is preferable that the substrate does not have a ground layer in a region directly under the contact portion.

8‧‧‧ Probes

9, 10, 11‧‧ ‧ probe card

12‧‧‧LSI Tester

14‧‧‧ Wafer Test System

16‧‧‧ card holder

18‧‧‧ wafer chuck

19‧‧‧ Wafer

20‧‧‧Contact pin

22‧‧‧Contacts

24‧‧‧Substrate

24B‧‧‧ bottom

24T‧‧‧ surface

25‧‧‧Connecting wiring

25s, 28E‧‧‧ short-term

26‧‧‧ coaxial cable

28‧‧‧Probe

28T‧‧‧ front end

30‧‧‧ Fixed Department

32‧‧‧Center conductor

34‧‧‧ dielectric

36‧‧‧Outer conductor

38‧‧‧Protective coating

40‧‧‧Connecting Department

4‧‧‧Ditch

42T‧‧‧ top surface

44, 45‧‧‧through hole

46‧‧‧Area

Fig. 1 is a view showing a wafer test system having a prober, a probe card, and an LSI tester in an embodiment of the present invention.

Fig. 2 is a view showing a state in which the probe card is viewed from the bottom surface side in the embodiment of the present invention.

Fig. 3 is a view showing the relationship between the probe and the coaxial line in the embodiment of the present invention.

Fig. 4 is a view showing a state in which the broken line X region of Fig. 1 is viewed from the front side and the bottom side.

Fig. 5 is a view showing a modification of the probe card of the wafer test system in the embodiment of the present invention.

Fig. 6 is a plan view and an impedance characteristic diagram in the case where the ground layer in the region immediately below the connection portion is not treated and removed in the embodiment of the present invention.

Figure 7 is a diagram showing a wafer testing system of the prior art.

Hereinafter, embodiments of the present invention will be described in detail using the drawings. In addition, In the following, the same elements are denoted by the same reference numerals, and the description thereof will be omitted. Further, in the description herein, the symbols previously described are used as needed.

1 is a diagram showing a wafer test system 14 having a prober 8, a probe card 10, and an LSI tester 12. Fig. 2 is a view showing a state in which the probe card 10 is viewed from the bottom surface (plate surface) 24B side of the substrate 24.

The probe device 8 is a positioning device for electrically and mechanically combining the wafer 19 on which a plurality of LSI wafers are formed and the LSI tester 12 via the probe card 10. The prober 8 has a card holder 16 and a wafer chuck 18; the card holder 16 serves as a support for supporting the probe card 10, and the wafer chuck 18 is used to hold The wafer 19 is a detected portion of the object detected by the LSI tester 12.

The LSI tester 12 is a main detecting device in the detecting step of the wafer 19, and is a device having a function of performing good or bad judgment and level discrimination, which is arbitrarily designed to test an electrical signal of the LSI chip by programming. (Test mode) is applied to the LSI chip, and the output response from the LSI chip is received and compared with the expected value at the time of good quality. The LSI tester 12 has a contact pin 20 for making contact with the contact portion 22 of the probe card 10 in order to apply the aforementioned test mode. The contact pin 20 is referred to as a so-called elastic probe (POGOPin), and the contact portion 22 is referred to as a so-called elastic (POGO) seat.

The probe card 10 includes a substrate 24, a plurality of contact portions 22, a plurality of coaxial wires 26, a plurality of probes 28, and a fixing portion 30. The substrate 24 is made of a resin such as epoxy. The contact portions 22 are disposed on the surface (plate surface) 24T of the substrate 24, and the plurality of coaxial wires 26 are connected to the plurality of contact portions. 22. The plurality of probes 28 are connected to a plurality of coaxial wires 26, and the fixing portions are disposed on the bottom surface 24B of the substrate 24. Here, the probe 28, the coaxial line 26, and the contact portion 22 are used for testing the high frequency of the LSI wafer. Here, although the high frequency is different depending on the use of the LSI chip, etc., for example, a frequency of 10 MHz or more can be set as a high frequency, and of course, a frequency lower than 10 MHz can be set as a high frequency, or a frequency higher than 10 MHz can be used. Set to high frequency.

Figure 3 is a diagram showing the relationship between the coaxial line 26 and the probe 28 that is in contact with the wafer 19. As shown in the XY line sectional view of FIG. 3 (lower side view of FIG. 3), the coaxial line 26 includes an inner conductor 32, a dielectric body 34, an outer conductor 36, and a protective cover 38; the dielectric body 34 The inner conductor 32 is coated, the outer conductor 36 covers the dielectric body 34, and the protective coating 38 covers the outer conductor 36. The inner conductor 32, the dielectric body 34, the outer conductor 36, and the protective covering 38 are coaxially nested. The inner conductor 32 is formed, for example, by a single wire or a stranded wire of a silver-plated soft copper wire or a silver-plated copper-plated copper wire. The dielectric body 34 is made of, for example, polyethylene. The outer conductor 36 is made of, for example, a braided wire made of a silver-plated soft copper wire or a tin-plated soft copper wire. The protective coating 38 is made of, for example, vinyl. Further, the outer conductor 36 is grounded to have a zero volt potential (ground potential).

The coaxial line 26 has a characteristic impedance ZA of the coaxial wire 26 when the inner diameter of the outer conductor 36 is DAmm, the diameter of the inner conductor 32 is dAmm, and the relative dielectric constant of the dielectric body 34 is ε A . Determined by 138/√ ε Axlog10(DA/dA). Here, the coaxial line 26 is matched with the impedance of the substrate 24, and the impedance is set, for example, to 50 Ω. Further, the outer diameter of the coaxial line 26 DA _all Just one example is 620μm to 960 m, and the length LA _all Just one example of the coaxial line 26 is 50mm to 100mm. One end of the inner conductor 32 of the coaxial line 26 is connected to the probe 28, and the other end is directly connected to the contact portion 22 as will be described later.

As previously mentioned, the base end portion 28E of the probe 28 is coupled to the inner conductor 32 of the coaxial line 26. Specifically, it is joined and fixed by welding to form the connecting portion 40. Further, the diameter of the connecting portion 40 is determined according to the amount of the welding consumable required for joining.

The fixing portion 30 is a portion that allows the probe 28 to pass and that fixes the probe 28 so as not to swing. Further, the front end portion 28T of the probe 28 for detecting the wafer 19 is attached to the output side of the fixing portion 30 so as to protrude. The fixing portion 30 is made of, for example, an epoxy resin. The fixing portion 30 has a predetermined width so that the probe 28 can withstand the stress when it comes into contact with the input and output terminals of the wafer 19.

Hereinafter, the arrangement relationship between the substrate 24 and the coaxial line 26 and the like will be described in detail using FIGS. 1 , 2 , and 4 . Fig. 4 is a view showing a state in which the broken line X region of Fig. 1 is viewed from the side of the front surface 24T and the side of the bottom surface 24B. In addition, in the first drawing, the coaxial wires 26 are simply arranged one by one from the fixing portion 30 in the outer diameter direction. However, as shown in FIGS. 2 and 4, the coaxial line 26 is actually provided. A plurality of roots are present and each is directly connected to the corresponding contact portion 22.

In the substrate 24, a region in which the coaxial line 26 is disposed in a region where the card holder 16 is disposed is provided with a groove portion 42 for forming a groove having a size and a width that can accommodate a plurality of coaxial lines 26. The width of the groove portion 42 can be, for example, 4.25 mm, and the depth can be, for example, 1.5 mm. Further, the groove portion 42 can be formed by applying a concave process using a cutting jig (not shown) or the like.

Further, in the substrate 24, a through hole portion 44 through which a through hole penetrating directly to the coaxial line 26 of the contact portion 22 is formed is provided in a region where the groove portion 42 is provided. The through hole portion 44 has a diameter slightly larger than the outer diameter DA _{all of the} coaxial line 26 and is disposed in the vicinity of the contact portion 22 . For example, the diameter of the hole through the hole portion 44 can be set to 1.5 mm. Here, the vicinity of the connecting portion 22 means a position at which the length of the coaxial wire 26 is drawn along the surface 24T side. In the vicinity of the connection portion 22, it is preferable that the through hole portion 44 is disposed between the contact portion 22 belonging to the connection destination of the coaxial line 26 and the adjacent contact portion 22. Further, the through hole portion 44 can be formed by using an opening jig or the like (not shown).

As described above, after the groove portion 42 and the through hole portion 44 are formed, the coaxial line 26 is disposed along the bottom surface 24 of the substrate 24 in a region where the card holder 16 is not disposed, and the card holder 16 is disposed. In the region, the inner conductor 32 is directly connected to the contact portion 22 while passing through the through hole portion 44 along the top surface 42T of the groove portion 42 and passing through the through hole portion 44.

Next, the action of the probe card 10 of the wafer test system 14 will be described. As described above, in the probe card 10, the coaxial line 26 matching the impedance of the substrate 24 is elongated and passes through the through hole portion 44, and the inner conductor 32 of the coaxial line 26 is directly connected to the contact portion 22. . That is, the contact portion 22 is not connected via the connection wiring 25 of the substrate 24 as in the prior art. Thereby, since the electric resistance between the coaxial wire 26 and the substrate 24 can be integrated, excellent high frequency characteristics can be ensured.

Hereinafter, the probe card 11 which is a modification of the probe card 10 will be described. Figure 5 is a diagram showing a wafer test system 15 having a prober 8, a probe card 11, and an LSI tester 12. The description will be given focusing on the difference between the probe card 11 and the probe card 10.

The probe card 11 is different from the probe card 10, and the groove portion 42 is not formed. Further, the through hole portion 45 of the probe card 11 and the through hole portion 44 of the probe card 10 are located. The difference is set, so the difference is described in detail.

The through hole portion 45 is provided in a region other than the card holder 16 where the card holder 16 is not disposed, that is, in a region where the card holder 16 is not disposed, so as to penetrate from the bottom surface 24B of the substrate 24 to the surface 24T. That is, the through hole portion 45 is provided closer to the inner diameter side of the probe card 11 than the card holder 16. The penetrating portion 45 has a diameter slightly larger than the outer diameter DA _{all of the} coaxial line 26, and for example, the diameter of the through hole portion 45 can be set to 1.5 mm. Further, the through hole portion 45 can be formed by using an opening jig or the like (not shown).

As described above, after the through hole portion 45 is formed, the coaxial line 26 is disposed along the bottom surface 24B of the substrate 24 in the region where the card holder 16 is not disposed, and passes through the through hole portion 45 toward the substrate 24 After the surface 24T side is pulled out, it is disposed along the surface 24T of the substrate 24 toward the connecting portion 22, and the inner conductor 32 is directly connected to the contact portion 22.

As described above, in the probe card 11, similarly to the probe card 10, the coaxial wire 26 is directly connected to the contact portion 22 without passing through the connection wiring 25 in the dielectric substrate 24. Therefore, the same effect as the probe card 10 is achieved. Further, as described above, in the probe card 11, although the coaxial line 26 is disposed along the surface 24T of the substrate 24, the case may be formed on the surface 24T of the substrate 24 and the groove portion 42. In the same groove, the coaxial wire 26 is disposed so as to accommodate the coaxial wire 26 in the groove, and the inner conductor 32 is directly connected to the contact portion 22.

Further, the probe cards 10 and 11 are described with respect to all of the probes 28, the coaxial wires 26, and the connection portion 22 for performing high-frequency testing of the LSI wafer, but of course, some of them may be used for performing the test. Low frequency test. At this time, the coaxial line 26 for high frequency can also be directly connected to the contact portion 22 as described above, and the low frequency can be used. Similarly to the conventional technique, the coaxial line 26 is connected to the connecting portion 22 via the connection wiring 25, but it is of course possible to directly connect the high-frequency and low-frequency coaxial wires 26 to the contact portion 22.

Further, it is known that in any of the probe cards 10 and 11, the contact portion 22 is also disposed in a region directly under the contact portion 22 by not providing a ground layer or performing a removal (removal) process. The impedance characteristics are improved. Here, the region directly under the contact portion 22 refers to a region overlapping the contact portion 22 when the contact portion 22 is viewed in plan in the substrate 24 . Further, the ground layer is a wiring provided inside the substrate 24. The ground plane is grounded to a zero volt potential (ground potential) and has a shielding effect that isolates noise from the outside.

The upper left side view of Fig. 6 shows a plan view and an impedance characteristic diagram when the process of removing the ground layer is not performed in the region directly under the contact portion 22. The top right side view of Fig. 6 shows a plan view and impedance characteristics when the ground layer is removed in the region directly under the contact portion 22, and the diameter of the contact portion 22 is substantially the same as the area 46 where the ground layer is removed. Figure. The upper right side view of Fig. 6 shows a plan view and an impedance characteristic diagram when the ground layer is removed in the region directly under the contact portion 22, and the region 46 where the ground layer is removed is made larger than the diameter of the contact portion 22. . Further, each of the lower drawings of Fig. 6 is an impedance characteristic map measured by a TDR (Time Domain Reflectometry) method well known for measuring a characteristic impedance.

As shown in the diagram on the left side of Fig. 6, when the treatment for removing the ground layer is not performed in the region directly under the contact portion 22, the impedance of the contact portion 22 is about 24 Ω. On the other hand, as shown in the figure of the center of FIG. 6, the process of removing the ground layer is performed in the area directly under the contact portion 22, and the diameter of the contact portion 22 is removed. When the region 46 of the ground layer has substantially the same area, the impedance of the contact portion 22 is about 30 Ω. Further, as shown in the diagram on the right side of FIG. 6, the process of removing the ground layer is performed in the region directly under the contact portion 22, and the region 46 from which the ground layer is removed is made larger than the diameter of the contact portion 22. At this time, the impedance of the contact portion 22 becomes about 40 Ω.

It is known from the foregoing that the impedance of the contact portion 22 can be integrated to be more similar to the ideal impedance (with the substrate 24 and the ground layer by directly removing the ground layer in the region directly under the contact portion). The impedance integrated with the coaxial line 26 (for example 50 Ω)). Further, it is known that when the ground layer is removed, it is also larger than the diameter of the contact portion 22, so that the impedance can be more approximated. Thus, by removing the ground layer and improving the impedance, the parasitic capacitance existing between the contact portion 22 and the ground layer and adversely affecting the impedance characteristics can be improved by the removal of the ground layer. As described above, by removing the ground layer in the region directly under the contact portion 22, the impedance of the contact portion 22 can be improved, and excellent high-frequency characteristics can be ensured.

Further, although no other region is provided between the contact portion 22 and the region 46 where the ground layer is removed, other regions may be provided between the contact portion 22 and the region 46. For example, in the case where a power supply layer, a signal layer or a dummy layer is disposed between the surface 24T where the contact portion 22 is provided and the ground layer, even if the region directly under the contact portion 22 is removed as the region 46 in the layers The same effect can be achieved when the size is approximately the same.

In addition, although the probe cards 10 and 11 are described as a cantileve type, other structures may be used. For example, even a vertical type, a blade type, or the like may have the same effect.

8‧‧‧ Probes

10‧‧‧ probe card

12‧‧‧LSI Tester

14‧‧‧ Wafer Test System

16‧‧‧ card holder

18‧‧‧ wafer chuck

19‧‧‧ Wafer

20‧‧‧Contact pin

22‧‧‧Contacts

24‧‧‧Substrate

24B‧‧‧ bottom

24T‧‧‧ surface

26‧‧‧ coaxial cable

28‧‧‧Probe

30‧‧‧ Fixed Department

32‧‧‧Center conductor

42‧‧‧Ditch

42T‧‧‧ top surface

44‧‧‧through hole

Claims (4)

A probe card includes a substrate having a first plate surface on which a contact portion for contacting a detecting device is disposed, and a second plate surface opposite to the first plate surface, wherein the substrate includes a ground layer. The ground layer is disposed inside the substrate between the first plate surface and the second plate surface; the probe is in contact with the detected portion detected by the detecting device; and the fixing portion is disposed in the second portion a plate surface, the intermediate portion of the probe is fixed; and a coaxial wire having a center conductor and an outer conductor, wherein one end of the center conductor is connected to the probe, and the other end of the center conductor is directly connected to the contact portion; In the substrate, when the contact portion is viewed in plan from the first plate surface side, the ground layer is removed in a region directly under the contact portion of the region overlapping the contact portion. The probe card according to claim 1, wherein the substrate has a groove portion, and a groove provided in a region where the front coaxial line is disposed is formed in a region where a support portion for supporting the substrate is disposed And the through hole portion is formed with a through hole through which the coaxial line directly connected to the contact portion penetrates in a region where the groove portion is provided. The probe card according to claim 1, wherein the substrate has a through hole portion and is provided in a region where a support portion for supporting the substrate is disposed. A region other than the domain is formed with a through hole through which the coaxial line directly connected to the contact portion penetrates. The probe card according to any one of the preceding claims, wherein the area of the substrate in which the ground layer is removed is equal to or larger than the area of the substrate directly under the contact portion. The area of the area directly below the contact.