JP2014160050A - Substrate for probe card and probe card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe card that suppresses a reduction in insulation resistance between a plurality of internal wirings even when surface polishing is performed.SOLUTION: A substrate 3 for a probe card includes a base substance 1 including a plurality of mullite particles, and a plurality of internal wirings 2 formed inside the base substance 1. A distance between the plurality of internal wirings 2 is 50 to 250 μm, and an average particle diameter of the plurality of mullite particles is 2.0 to 3.0 μm.

Description

  The present invention relates to a probe card substrate having fine wiring for measuring electrical characteristics of a semiconductor wafer and a probe card using the same.

  As a device for detecting a defective product of the semiconductor element, a probe card capable of simultaneously inspecting electrical characteristics of a large number of semiconductor elements at the same time in a semiconductor wafer state is known (see, for example, Patent Document 1). ).

  This probe card includes a wiring board on which fine wiring is formed on the main surface and inside of an insulating base, and a plurality of measuring terminals called probe pins arranged on the surface of the wiring board with high precision. The probe pins are applied to the terminals of a large number of semiconductor elements, and the output when a voltage is applied is measured and compared with an expected value, whereby the quality of the large number of semiconductor elements is collectively determined.

  In such a probe card, in order to reduce the difference in thermal expansion coefficient between the probe card substrate and the semiconductor wafer, an attempt has been made to apply a mullite sintered body as an insulating base of the probe card substrate ( For example, see Patent Document 2).

Japanese Patent Laid-Open No. 11-160356 JP 2012-73162 A

  Immediately after firing, the probe card substrate has good insulation resistance between a plurality of internal wires inside the base made of mullite sintered body, but the tip of the probe pin provided on the surface of the probe card substrate is high. If the surface of the probe card substrate is polished to align the thickness, the insulation resistance between the multiple internal wires of the probe card substrate may decrease. In the future, if the distance between the multiple internal wires is reduced There is a possibility that a problem related to insulation resistance becomes conspicuous.

  A probe card substrate according to an aspect of the present invention includes a base including a plurality of mullite particles and a plurality of internal wirings formed in the base. The distance between the plurality of internal wirings is 50 to 250 μm, and the average particle diameter of the plurality of mullite particles is 2.0 to 3.0 μm.

  A probe card according to another aspect of the present invention includes the probe card substrate configured as described above and a probe terminal provided on the probe card substrate.

In the probe card substrate according to one aspect of the present invention, the distance between the plurality of internal wirings is 50 to 250 μm, and the average particle diameter of the plurality of mullite particles is 2.0 to 3.0 μm. The insulation resistance between wiring is improved. That is, the probe card substrate according to one aspect of the present invention has a plurality of internal wirings even when the density of the internal wirings is increased and the distance between the internal wirings is 50 to 250 μm. Sufficient characteristics can be ensured regarding the insulation resistance between the wirings.

  A probe card according to another aspect of the present invention includes a probe card substrate configured as described above and a probe terminal provided on the probe card substrate, thereby improving the inspection accuracy of the electrical characteristics of the semiconductor wafer. Can do.

(A) is a top view which shows the probe card in embodiment of this invention, (b) is a longitudinal cross-sectional view in the AA of the probe card shown by (a). FIG. 2 is an enlarged view of a portion indicated by a symbol B in the probe card shown in FIG. (A) is a top view of the probe card shown in FIG. 2, (b) is a plan view of the position indicated by line CC in the probe card shown in FIG. 2, (c) FIG. 3 is a bottom view of the probe card shown in FIG. 2. It is a schematic cross section explaining the crack in the base | substrate of the board | substrate for probe cards. It is a schematic cross section explaining the manganese titanate particles in the base of the probe card substrate.

  Exemplary embodiments of the present invention will be described with reference to the drawings.

  The probe card in the embodiment of the present invention includes a probe card substrate 3 and probe terminals 5 provided on the probe card substrate 3.

  As shown in FIGS. 1 to 3, the probe card substrate 3 includes a base 1 made of a ceramic sintered body, and internal wiring 2 (inner layer pattern 2a and via conductor 2b provided inside the base 1). And a surface wiring layer 4 formed on the surface of the substrate 1.

  The substrate 1 is composed of a plurality of ceramic insulating layers 1a, and each ceramic insulating layer 1a is formed of a ceramic sintered body containing mullite as a main component. Hereinafter, a ceramic sintered body containing mullite as a main component is also referred to as a mullite sintered body.

  Here, in the probe card substrate 3 of the present embodiment, the mullite which is the main component of the mullite sintered body constituting the base 1 is present in the form of particles.

In the present embodiment, the average particle size of the plurality of mullite particles is desirably 2.0 to 3.0 μm. Since the probe card substrate 3 of the present embodiment has such a configuration, the density of the plurality of internal wirings 2 will increase in the future, and the distance between the plurality of internal wirings 2 will be 50 to 250 μm. In this case, a sufficient insulation resistance of 1 × 10 ⁹ to 1 × 10 ¹¹ Ω can be ensured.

  As shown in FIG. 4, when the surface of the probe card substrate 3 is polished, cracks may occur in the base 1. In the probe card substrate 3 of the present embodiment, since the average particle diameter of the plurality of mullite particles is 2.0 μm or more, even if a crack starts to enter, the crack progresses in the progress direction of the crack. There is a high possibility that the surface of the mullite particles that will interfere is likely to appear, and it is difficult to lead to a decrease in insulation resistance between the plurality of internal wirings 2. As will be described later, the average particle diameter of the plurality of mullite particles is preferably 3.0 μm or less from the viewpoint of the formation accuracy of the surface wiring layer 4.

  In the probe card substrate 3 of the present embodiment, when the average particle diameter of the plurality of mullite particles is 2.4 to 3.0 μm, the insulation resistance between the plurality of internal wirings 2 is further improved. Can do.

  The average particle size of the plurality of mullite particles is measured by the intercept method. Specifically, a portion of the mullite sintered body (a part of the substrate 1) is cut out from the probe card substrate 3 and polished, etched, and then photographed at a magnification of 500 times to obtain a photograph of the cross-sectional structure. Further, 10 straight lines were drawn on the photograph, and the average value of the lengths of the straight line portions crossing each mullite particle was calculated and used as the average particle diameter.

  When the insulating substrate 1 is a mullite sintered body, the thermal expansion coefficient (room temperature to 300 ° C.) of the insulating substrate 1 can be set in the range of 3 to 5 × 10 −6 / ° C. Thereby, the probe card substrate 3 of the present embodiment can reduce misalignment between the measurement terminal provided on the probe card substrate 3 and the measurement pad formed on the surface of the Si wafer during the thermal load test, It can be suitably used for inspection of electrical characteristics.

  Next, the manufacturing method of said probe card board | substrate 3 is demonstrated.

First, in order to form the substrate 1, a mullite (3Al ₂ O ₃ · 2SiO ₂ ) powder having a purity of 99% or more and an average particle size of 0.5 to 2.5 μm is used. By making the average particle size of mullite powder 0.5 μm or more, sheet formability is improved, and by making it 2.5 μm or less, it is possible to promote densification by firing at a temperature of 1420 ° C. or less. It becomes.

Next, with respect to 100 parts by mass of mullite powder, 2.0 to 4.0 parts by mass of Mn ₂ O ₃ powder, 4.0 to 8.0 parts by mass of TiO ₂ powder, and 0.4 to 0.4% of MoO ₃ powder. Add 2.1 parts by weight. In this case, the Mn ₂ O ₃ powder used as an additive should have an average particle diameter of 0.5 to 3 μm, a TiO ₂ powder of 0.5 to ₂ μm, and a MoO ₃ powder of 0.5 to ₂ μm. .

The purity of Mn ₂ O ₃ powder, TiO ₂ powder, and MoO ₃ powder is preferably 99% by mass or more. Thereby, sheet moldability can be improved, diffusion of Mn, Ti, and Mo can be improved, and sinterability at a temperature of 1380 ° C. to 1420 ° C. can be improved.

When the probe card substrate 3 is manufactured, if the MoO ₃ powder is added together with the Mn ₂ O ₃ powder and the TiO ₂ powder to the mullite powder, the seepage of the glass phase can be suppressed, resulting in poor appearance due to foreign matter adhesion. It becomes difficult. When the MoO ₃ powder and the TiO ₂ powder are in a predetermined ratio, whitening in the vicinity of the wiring of the base body 1 obtained can be suppressed, thereby increasing the color contrast between the base body 1 and the wiring. It is possible to reduce the numerical variation when inspecting.

  Mn, Ti, and Mo may be added as carbonates, nitrates, acetates, and the like that can form oxides by firing in addition to the oxide powders described above.

Furthermore, for the reason that densification of the mullite-based sintered body and simultaneous sintering of the base body 1 and the internal wiring 2 are enhanced, it is selected from the group of Ca, Sr, B and Cr with respect to 100 parts by mass of mullite powder. One or more oxide powders (CaO powder, SrO powder, B ₂ O ₃ powder, Cr ₂ O ₃ powder) or a powder comprising carbonate, nitrate, acetate that can form oxides by firing The thermal expansion coefficient of the probe card substrate 3 in the form may not be greatly changed, and the chemical resistance may not be significantly deteriorated.

  Next, an organic binder and a solvent are added to the mixed powder, and a slurry is prepared by thoroughly mixing and dispersing using a ball mill or the like. Then, the slurry is formed into a green sheet by a molding method such as a doctor blade method or an injection method. Is made. Alternatively, an organic binder is added to the mixed powder, and a green sheet having a predetermined thickness is produced by a method such as press molding or rolling. In addition, although the thickness of a green sheet can be 50-300 micrometers, for example, it is not specifically limited.

  Then, a through hole having a diameter of 50 to 250 μm is appropriately formed on the green sheet by die punching, micro drill, laser, or the like.

  Thus, with respect to the produced green sheet, copper (Cu) powder and tungsten (W) powder become a predetermined ratio (Cu is 40 to 60% by volume, W is 40 to 60% by volume). A conductor paste is prepared by mixing, and the conductor paste is filled into the through holes of each green sheet to form a conductor to be a via-hole conductor 2b, and is printed and applied by a method such as screen printing or gravure printing to form the inner layer pattern 2a. A pattern is formed.

  In this conductor paste, alumina powder or a mixed powder of the same composition as that of the substrate 1 may be added in addition to the above metal powder in order to improve the adhesion to the substrate 1, and further, such as Ti. You may add an active metal or those oxides in the ratio of 0.05-2 volume% with respect to the whole conductor paste.

  The conductor paste need not have a composition limited to the above composition, and may be any composition that reduces the wiring resistance. In addition, a part of the composition that has a small influence on the wiring resistance and electrical characteristics is partially composed. You can change it. For example, since the via hole conductor 2b generally tends to have a larger cross-sectional area than the inner layer pattern 2a, the via hole conductor 2b and the wider inner layer pattern 2a are partially made of tungsten (W), molybdenum (Mo), You may form with the alloy.

  Thereafter, the green sheet on which the conductor paste is printed is aligned and laminated and pressure-bonded, and then the laminate is fired in a non-oxidizing atmosphere (nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen).

  Here, the maximum temperature during firing is preferably set to 1380 ° C. to 1420 ° C. When the maximum temperature during firing is 1380 ° C. to 1420 ° C., the mullite sintered body can be densified by adjusting the holding time at a temperature in this range.

  Further, in the mullite sintered body that is the base body 1 constituting the probe card substrate 3 of the present embodiment, when a predetermined amount of at least Mn, Ti, and Mo is contained and fired, neck growth of mullite particles can be suppressed, so that mullite. Thus, a mullite sintered body having a high Young's modulus can be obtained.

As shown in FIG. 5, in the substrate 1 made of a mullite sintered body containing Mn ₂ O ₃ powder and TiO ₂ powder, manganese titanate crystal phase (MnTiO ₃ ) is acicular particles. (Hereinafter also referred to as manganese titanate particles 6). It is preferable that the manganese titanate particles 6 are contained in a mass ratio of 1.1% or more with respect to the substrate 1 because the chemical resistance of the substrate 1 is improved.

As an index of chemical resistance of the substrate 1 at this time, the initial mass of the mullite sintered body and the mass of the mullite sintered body after being immersed in a 40% by weight aqueous solution of potassium hydroxide at 100 ° C. for 5 hours are used. Measured weight loss rate (“initial mass of mullite sintered body” − “mass of mullite sintered body after being immersed in an aqueous solution of 40 mass% potassium hydroxide at 100 ° C. for 5 hours”) / “mullite quality The initial mass of the sintered body ”× 100 [%] was calculated, and the case where the mass change rate was 0.12% by mass or less was used as an index for passing.

Further, when the mass ratio of the manganese titanate particles 6 to the mullite sintered body exceeds 1.5 mass%, the manganese titanate crystal has a low insulation resistance value, so that the average particle size of mullite is as described above. Even if the thickness is 2.4 to 3.0 μm, the insulation resistance value between the internal wirings 2 is 1 × 10 ⁹ to 1 × 10 ¹¹ Ω, and the insulation resistance is somewhat reduced. Therefore, the mass ratio of the manganese titanate particles 6 to the mullite sintered body is preferably 1.5% by mass or less.

  Further, it is preferable that the maximum particle size of the manganese titanate particles is 15 μm or less because the possibility that the insulation resistance between the wirings is lowered can be reduced even when the distance between the internal wirings 2 is as small as about 50 μm.

  That is, in the probe card substrate 3 of the present embodiment, the base 1 is provided with a plurality of manganese titanate particles 6 having a maximum particle size of 15 μm or less, 1.1 to 1 with respect to the mullite sintered body. .5 mass% can ensure higher characteristics regarding the insulation resistance between the plurality of internal wirings 2, and even if the distance between the internal wirings 2 is as small as about 50 μm, Insulation can be improved more stably.

  The maximum diameter of the manganese titanate particles 6 contained in the substrate 1 can be obtained as follows. Since the manganese titanate particles 6 are needle-like crystals, the major axis of the manganese titanate particles 6 is the particle size of the manganese titanate particles 6. First, an area of 300 μm square on the surface of the sample polished for analysis is observed using a scanning electron microscope provided with an X-ray microanalyzer (EPMA) to confirm the manganese titanate particles 6. Among the manganese titanate particles 6 confirmed in the 300 μm square region, the longest diameter of the largest particle was measured and set as the maximum diameter of the manganese titanate particles 6.

  In addition, about the mass ratio in which the crystalline phase of manganese titanate is contained in a mullite sintered body, the base | substrate 1 is grind | pulverized and the quantitative analysis by X-ray diffraction is performed, and the mass ratio with respect to a mullite sintered body is calculated. Can be determined by

  Further, when producing the probe card substrate 3 of the present embodiment, the rate of temperature increase from 1000 ° C. to densify the mullite sintered body to the highest firing temperature is 50 ° C./hr to 150 ° C./hr, It is desirable that the temperature is 75 ° C./hr to 100 ° C./hr, and the rate of temperature decrease from the highest firing temperature to 1000 ° C. is 50 ° C./hr to 300 ° C./hr, in particular 50 ° C./hr to 100 ° C./hr. It is desirable.

  Furthermore, the firing atmosphere is a non-oxidizing atmosphere containing hydrogen and nitrogen and having a dew point of + 30 ° C. or lower, particularly + 25 ° C. or lower, for the purpose of suppressing diffusion of Cu in the internal wiring 2. desirable. If the dew point during firing is + 30 ° C or less, the oxide ceramics react with moisture in the atmosphere during firing to form an oxide film, which reduces the possibility of this oxide film reacting with copper. The resistance of the conductor can be reduced. Note that an inert gas such as argon gas may be mixed in this atmosphere as desired.

Next, the surface of the sintered wiring board is polished, and a sputter method is used to sequentially form a bonding metal layer such as titanium and chromium and a main conductor layer such as copper on the entire surface of the wiring board, and then a conductive thin film Layer. You may form a barrier layer etc. as needed. Next, the conductive thin film layer was patterned by photolithography to form a thin film wiring. Next, an electrolytic plating film of nickel and gold was formed in order on the surface of the thin film wiring, and the surface wiring layer 4 was formed on the surface of the wiring board, whereby the probe card substrate 3 was obtained.

  The probe card substrate 3 manufactured by the method described above includes Cu and W as main components, has an internal wiring 2 with low wiring resistance, and has a thermal expansion coefficient equal to that of the Si wafer to be inspected. It will be close.

  Next, a Si probe terminal 5 is joined to the surface of the surface wiring layer 4 formed on the surface of the probe card substrate 3 to produce a probe card.

For 100 parts by mass of mullite powder with a purity of 99% and an average particle size of 2.1 μm, 2% by mass of Mn 2 O 3 powder with a purity of 99% and an average particle size of 1.5 μm and an average particle size of 99% purity Is mixed with 4% by mass of 1.0 μm of TiO ² powder and 99% of purity and MoO ₃ powder with an average particle diameter of 1.0 μm at a ratio of 0.5% by mass, and further molded organic resin (organic binder). ) Was mixed with an acrylic binder and toluene as an organic solvent to prepare a ceramic slurry, which was then formed into a 200 μm thick sheet by a doctor blade method to prepare a ceramic green sheet.

  An inner layer pattern is formed by printing on the surface of each green sheet a conductor paste prepared with Cu powder and W powder so that Cu is 45% by volume and W is 55% by volume on the produced green sheet. A ceramic green sheet structure in which a via hole conductor 2b was formed by forming 2a and filling a through-hole with a conductive paste was produced.

At this time, a part of the inner layer pattern is a linear pattern having a width of 100 μm and a length of 100 mm after baking for measuring the insulation resistance, and 51 evaluation patterns having each pattern distance of each dimension in Tables 1 to 5 are provided. A total of five layers were formed (so that the pattern distance could be measured at 50 locations). The inner layer pattern 2a was connected to the via hole conductor 2b, and a land pattern was formed at the end of the inner layer pattern 2a for connection to the via hole conductor 2b.

  Each ceramic green sheet structure produced in this way was aligned and 30 layers were laminated and pressed to produce a laminate.

  The obtained laminate was degreased at room temperature to 600 ° C. in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C., and then fired. The firing temperature was around 1380 ° C., and firing was performed in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C., followed by cooling to obtain a mullite sintered body. The substrate size was 340 mm × 340 mm and the thickness was 5 mm.

  The diameter of the mullite particles was adjusted by adjusting conditions such as slurry adjustment conditions, firing temperature, temperature profile, and keep time. As a result, samples of 12 levels were prepared with an average particle size of mullite particles ranging from 1.4 μm to 3.6 μm, including 5 levels of pattern distance in one substrate.

  Next, the surface of the produced wiring board was polished, and a conductive thin film of titanium and copper having a thickness of about 2 μm was sequentially formed on the entire surface of the wiring board using a sputtering method.

  Next, a thin film wiring was formed by patterning a conductive thin film of titanium and copper by photolithography. As a surface wiring pattern for evaluation, a linear pattern having a width of 50 μm and a length of 100 mm was formed.

Thin film formation was evaluated using a metallographic microscope. 5μ in the width direction on the surface wiring pattern for evaluation
If a pattern chipping of m or more occurs, it is determined that the pattern forming property is insufficient, and “bad” is determined, and if the pattern chipping dimension in the width direction is less than 5 μm, it is determined that there is sufficient pattern forming property and “good” " When the average particle size of the mullite particles is 3.2 μm or more, the formability of the thin film pattern becomes insufficient. It seems that pattern defects are likely to occur.

  Next, an electrolytic plating film of nickel and gold was formed in order on the surface of the thin film wiring, and the surface wiring layer 4 was formed on the surface of the wiring board, whereby the probe card substrate 3 was obtained.

  The insulation resistance value for each distance of the internal wiring 2 was measured for each level of the average particle diameter of each mullite particle. The insulation resistance was measured by measuring the current that flowed by applying a voltage of 100 V between the test terminals.

When the insulation resistance range between the internal wirings 2 of all 50 measured values is 1 × 10 ⁹ to 1 × 10 ¹¹ Ω, it is judged that it can be used as a high-density circuit board, and the insulation resistance between the internal wirings 2 When the range is 1 × 10 ⁹ to 1 × 10 ¹² Ω, it is judged as having a sufficient characteristic as a high-density circuit board, and “good”, and the insulation resistance includes a value smaller than 1 × 10 ⁹ Ω Was judged as “bad” because it was judged unusable.

  It was judged that the thin film pattern formability and the insulation resistance between the internal wirings 2 were both good or good as the probe card substrate 3, and it was judged good or good.

From the above, since the insulation resistance is 1 × 10 ⁹ to 1 × 10 ¹¹ Ω even if the distance between the internal wirings 2 is formed as high as 50 to 250 μm, the average particle size of mullite is 2.0 to 3.0 μm. It is desirable that

Even if the distance between the internal wirings 2 is 50 to 250 μm, the insulation resistance is 1 × 10 ⁹ to 1 × 10 ¹² Ω. Therefore, the average particle size of mullite is 2.4 to 3.0 μm. More desirable.

  A laminate was prepared in the same manner as in Example 1 except that the evaluation pattern was set such that the distance between the inner layer patterns was only 50 μm.

And by adjusting conditions such as slurry adjustment conditions, firing temperature, temperature profile, keep time, etc., as shown in Table 6 to Table 8, the diameter of mullite particles is 2.0 μm to 3.0 μm. Samples shown in Tables 6 to 8 were prepared in the same manner as in Example 1 except that the maximum particle size of the manganese titanate particles 6 was adjusted to 5 μm to 35 μm with respect to the particle size. Accordingly, the maximum particle size of the manganese titanate particles 6 is 5 μm to 35 μm with respect to each substrate having an average particle size of mullite particles of 2.0 μm, 2.4 μm, and 3.0 μm with a distance between patterns of 50 μm. A total of 21 types of samples were prepared.

  Evaluation of thin film formation was evaluated in the same manner as in Example 1. In all the samples, no pattern chipping occurred and it was found that there was good formability. In the same manner as in Example 1, the surface wiring layer 4 was formed on the surface of the wiring substrate, whereby the probe card substrate 3 was obtained.

  A 300 μm square region on the surface of each polished sample is observed using a scanning electron microscope equipped with an X-ray microanalyzer (EPMA), and the manganese titanate particles 6 are confirmed to confirm the sample manganese titanate particles. A maximum diameter of 6 was confirmed.

  About the mass ratio (content rate) of the crystalline phase of manganese titanate in the mullite sintered body, about 1 g is cut out from the substrate 1 and pulverized, and quantitative analysis by X-ray diffraction is performed. It calculated | required by calculating the mass ratio of the crystal phase of manganese titanate. In the case of cutting out, a portion not including the internal wiring 2 or the surface wiring layer 4 is cut out so that the mass ratio of the manganese titanate crystal phase to the mullite sintered body can be measured more accurately. Is good.

In the same manner as in Example 1, the insulation resistance value between the internal wirings 2 was measured. When the range of the insulation resistance value is 1 × 10 ⁹ to 1 × 10 ¹¹ Ω, it is determined that it can be used as a high-density circuit board, and the insulation resistance range between the internal wirings 2 is 1 × 10 ¹⁰ to 1 × 10. ^In the case of ¹¹ Ω, it was judged as “good” because it was judged to have sufficient characteristics as a high-density circuit board. When the insulation resistance range between the internal wirings 2 is 1 × 10 ¹⁰ to 1 × 10 ¹² Ω, it is judged as “excellent” because it is judged to have excellent insulation characteristics as a high-density circuit board.

  In Example 2, the thin film pattern formability was good in all samples. Those having an insulation resistance between the internal wirings 2 of “Yes” were judged to be usable as the probe card substrate 3, and “Yes” was determined in the overall judgment. Similarly, it was determined that the insulation resistance between the internal wirings 2 was “good” or “excellent” as the probe card substrate 3 and was determined as “good” or “excellent” in the overall determination.

  From the results of Tables 6 to 8, when the maximum particle size of the plurality of manganese titanate particles 6 is 15 μm or less, the insulation resistance between the internal wirings is the case where the maximum particle size of the manganese titanate particles 6 is 20 μm or more. It was found that the improvement was more stable than At this time, the content rate of the manganese titanate particle 6 was 1.1-1.5 mass%.

In addition, when the distance of the internal wiring 2 is wider than 50 μm, it is clear that the insulation resistance between the internal wirings 2 becomes higher. From this, when the average particle diameter of mullite is 2.0 to 3.0 μm, the insulation resistance becomes 1 × 10 ¹⁰ Ω or more even if the distance between the internal wirings 2 is formed at a high density of 50 to 250 μm. .

DESCRIPTION OF SYMBOLS 1 ... Base 1a ... Ceramic insulating layer 2 ... Internal wiring 2a ... Inner layer pattern 2b ... Via hole conductor 3 ... Probe card substrate 4 ... ... Surface wiring layer 5 ... Probe terminal 6 ... Manganese titanate particles

Claims (4)

A substrate comprising a plurality of mullite particles;
A plurality of internal wirings formed in the substrate,
A probe card substrate, wherein a distance between the plurality of internal wirings is 50 to 250 μm, and an average particle diameter of the plurality of mullite particles is 2.0 to 3.0 μm.   2. The probe card substrate according to claim 1, wherein an average particle diameter of the plurality of mullite particles is 2.4 to 3.0 μm.   3. The probe card substrate according to claim 1, wherein the base includes a plurality of manganese titanate particles having a maximum particle size of 15 μm or less. A probe card substrate according to claim 1;
A probe card comprising: a probe terminal provided on the probe card substrate.

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