Ceramics, probe guide component, probe card, and package inspection socket

Abstract

To provide a ceramic having a high coefficient of thermal expansion and a low dielectric constant.SOLUTION: 50.0 to 90.0 mass% of 2MgO and SiO2, a total of 8.0 mass% or more of one of 7.0 to 14.0 mass% of ZrO2 and 10.0 to 50.0 mass% of Al2O3 or both of 14.0 mass% or less of ZrO2 and 50.0 mass% or less of Al2O3, and 3.0 to 15.0 mass% of one or more selected from Y2O3, CaO, CeO2, and HfO2, wherein a crystalline structure of the is a cubic structure. ZrO2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to ceramics, probe guide components, probe cards, and sockets for package inspection. [Background technology]

[0002] For example, a probe card is used in the process of inspecting IC chips. FIG. 1 shows a cross-sectional view illustrating the configuration of a probe card, and FIG. 2 shows a top view illustrating the configuration of a probe guide. As shown in FIGS. 1 and 2, a probe card 10 is an inspection jig that includes needle-shaped probes 11 and a probe guide (probe guide component) 12 having a plurality of through-holes 12a for inserting the probes 11. An IC chip 14 is inspected by bringing the plurality of probes 11 into contact with the IC chip 14 formed on a wafer 13.

[0003] Patent Document 1 discloses ceramics made primarily of, by mass, 20.0 to 60.0% Si3N4 and 25.0 to 70.0% ZrO2. The ceramics disclosed in Patent Document 1 are excellent in strength, processability, etc., and are therefore suitable for use in probe guides and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 099370 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, IC chips for automotive applications and other applications have been required to operate at higher currents and voltages. This has led to the need for IC chips to operate at higher temperatures, and IC chip testing is now being conducted at higher temperatures. Probe guides do not directly contact the wafer; instead, the heat from the wafer is conducted through the probe. This means that although the temperature of the probe guide also rises, it remains at a lower temperature than the wafer. Therefore, using ceramics with a thermal expansion coefficient similar to that of the wafer material for the probe guide results in the problem of being unable to contact the probe accurately at the IC chip's location. This problem is more pronounced with IC chips that use wafers with a higher thermal expansion coefficient. Therefore, even at lower temperatures than the wafer, the probe guide must have the same thermal expansion coefficient as the wafer.

[0006] Here, the thermal expansion coefficient of silicon is 2.6×10 -6 On the other hand, the thermal expansion coefficient of wafer materials such as SiC and GaN, which have recently come into use and can be used at high temperatures, is 4.0 to 6.0 × 10 -6 Therefore, it is preferable that the thermal expansion coefficient of the ceramics used in the probe guide etc. is higher than that of the wafer, specifically 7.5 × 10 -6 / °C or more.

[0007] In IC chip testing, there is a demand for higher frequency test signals (currents). For this reason, ceramics used in probe guides and other devices must have a low dielectric constant. In other words, if the ceramic has a high dielectric constant, the area surrounded by the conductors acts like a capacitor, making it difficult for high-frequency current to flow. As a result, the signal propagation speed is slowed, causing synchronization errors in clock signals and other signals. For this reason, ceramics used in probe guides and other devices must have a sufficiently low dielectric constant, specifically, a dielectric constant of 9.0 or less.

[0008] Although the above mainly describes problems related to probe guides, similar problems occur in package inspection sockets. A package inspection socket is a socket that holds an IC chip for testing without mounting it on a printed circuit board, and like a probe guide, it has multiple fine through-holes.

[0009] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a ceramic having a higher coefficient of thermal expansion and a lower dielectric constant than silicon. [Means for solving the problem]

[0010] The inventors investigated ceramics that can be used in probe guides even when the wafer is at high temperature, and focused on forsterite (2MgO·SiO2).

[0011] Although forsterite has a high thermal expansion coefficient and a low dielectric constant, which meets the objectives of the present invention, it has the disadvantage of low bending strength. The present invention was completed by incorporating appropriate amounts of ZrO2 and Al2O3 into ceramics containing forsterite as the main phase in order to increase bending strength while maintaining a sufficiently high thermal expansion coefficient and a sufficiently low dielectric constant.

[0012] The present invention relates to "% by mass, 2MgO·SiO2: 50.0~90.0% ZrO2: 7.0 to 14.0% and Al2O3: 10.0 to 50.0%, or both ZrO2: 14.0% or less and Al2O3: 50.0% or less, totaling 8.0% or more; One or more selected from Y2O3, CaO, CeO2, and HfO2: 3.0 to 15.0%; Including, The crystal structure of the ZrO2 is a cubic system.

[0013] The preferred thermal expansion coefficient of the ceramic is 7.5×10 -6 / ° C. or more, and a preferred dielectric constant (25° C., 10 kHz) is 9.0 or less. The ceramics can be used, for example, in probe guide parts of probe cards or sockets for package inspection. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide ceramics that have a higher coefficient of thermal expansion than silicon, are less susceptible to plastic deformation, and have a low dielectric constant. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view illustrating the configuration of a probe card. [Figure 2] FIG. 2 is a top view illustrating the configuration of the probe guide. [Figure 3] FIG. 3 shows an example of the results of XRD measurement when identifying the crystalline phase. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, each requirement (chemical composition, crystal structure, etc.) of the ceramic of this embodiment will be described in detail. In the description of the content, "%" means "mass %" unless otherwise specified.

[0017] (2MgO·SiO2: 50.0 to 90.0%) 2MgO·SiO2 is effective in increasing the thermal expansion coefficient of ceramics. For this reason, 2MgO·SiO2 should be included at a content of 50.0% or more. However, if the 2MgO·SiO2 content is excessive, the bending strength of the ceramic may deteriorate, so its content should be 90.0% or less. The preferred lower limit of 2MgO·SiO2 is 54.5%, more preferably 60.0%, and even more preferably 65.5%. The preferred upper limit of 2MgO·SiO2 is 87.0%, more preferably 86.0%, and even more preferably 85.0%.

[0018] (ZrO2: 7.0-14.0% and Al2O3: 10.0-50.0%, or ZrO2: 14.0% or less and Al2O3: 50.0% or less, totaling 8.0% or more) Both ZrO2 and Al2O3 are effective in increasing the strength of ceramics, so one or both must be included. ZrO2 also contributes to increasing the thermal expansion coefficient. The minimum content limits for ZrO2 are 7.0% and 10.0% for Al2O3. On the other hand, if the ZrO2 content exceeds 14.0%, the volume ratio of ZrO2 in the ceramic increases, increasing the amount of zirconia present at the grain boundaries of forsterite, resulting in an excessively high dielectric constant of the ceramic. The same applies when the Al2O3 content exceeds 50.0%. For this reason, the upper limits for ZrO2 and Al2O3 are set at 14.0% and 50.0%, respectively.

[0019] The lower limit of the ZrO2 content is preferably 8.0%, and more preferably 9.0%. The upper limit of the ZrO2 content is preferably 12.0%, and more preferably 11.0%. The lower limit of the Al2O3 content is preferably 12.0%, and more preferably 15.0%, and even more preferably 20.0%. The upper limit of the Al2O3 content is preferably 46.0%, and more preferably 40.0%, and even more preferably 35.0%.

[0020] ZrO2 has a monoclinic, tetragonal, or cubic crystal structure. Generally, to impart high strength to ceramics, tetragonal ZrO2, which contains a few percent of oxides in solid solution, is preferred. However, this tetragonal ZrO2 undergoes a phase transition to monoclinic when exposed to low temperatures, for example, temperatures below 200°C, for long periods of time. This phase transition causes the dimensions of the ceramic to change. This phase transition occurs, for example, at temperatures above 40°C and becomes more pronounced at temperatures above 150°C.

[0021] Therefore, when such ceramics are used in a probe guide, dimensional changes occur as the temperature range increases, causing the position of the multiple through-holes and / or slits through which the probes pass to shift, which can hinder probe insertion. This is because the crystal structure changes in an operating environment where repeated heating and stress loads occur, and the original dimensions do not return to normal upon cooling. Furthermore, if the tetragonal crystal content exceeds a certain level, it may chemically react with moisture, etc. Therefore, the ZrO2 contained in the ceramic of this embodiment is cubic.

[0022] Here, the crystalline structure of ZrO2 is determined by the following procedure. Specifically, peak intensities are measured by XRD, and the peak intensities of each crystalline phase (monoclinic, cubic, and tetragonal) on the (200) plane of ZrO2 are determined, as shown in Figure 3. In Figure 3, the 34.2° angle indicated by △ is the monoclinic peak, the 34.9° angle indicated by ○ is the cubic peak, and the 35.3° angle indicated by □ is the tetragonal peak. In this application, considering ease of identification of the crystalline phase, the determination is made based on the intensity at a diffraction angle 2θ of approximately 35°. Then, when the sum of the above three peak intensities is taken as 100%, if the cubic peak intensity is 80% or more, the crystalline structure of ZrO2 is determined to be cubic. Note that to eliminate noise during measurement, a baseline can be drawn in the diffraction angle 2θ range of 32 to 38° to determine the above-mentioned peak intensities.

[0023] As mentioned above, if the amount of ZrO2 and / or Al2O3 is large, they tend to aggregate at the grain boundaries of forsterite, resulting in an excessively high dielectric constant. This tendency becomes more pronounced when the ZrO2 content is high. For this reason, it is preferable to limit the amount of ZrO2 in terms of volumetric ratio. Specifically, it is preferable to limit the volumetric ratio of ZrO2 to 10.0% or less. A more preferable volumetric ratio is 8.0% or less.

[0024] (One or more selected from Y2O3, CaO, CeO2, and HfO2: 3.0 to 15.0%) To give ZrO2 a cubic crystal structure, it is preferable to include a certain amount of stabilizer, such as Y2O3. Y2O3 is the most common stabilizer, but other stabilizers include CaO, CeO2, and HfO2. The content of one or more stabilizers selected from Y2O3, CaO, CeO2, and HfO2 should be 3.0% or more. However, excessive content reduces the thermal expansion coefficient of the ceramic. Therefore, the total stabilizer content is preferably 15.0% or less. The preferred upper limit of the total stabilizer content is 12.0%, more preferably 10.0%, and even more preferably 8.0%. The preferred lower limit of the total stabilizer content is 4.0%, more preferably 5.0%.

[0025] (Other compounds) In addition to the above compounds, the ceramic of this embodiment may also contain sintering aids as needed. Examples of sintering aids include TiO2, SiO2, MoO3, Ta2O5, Yb2O3, LaO, and B2O3. The content of the sintering aid is not particularly limited, but to obtain dense ceramics, it is preferable to include 0 to 5.0% of one or more selected from these compounds. If the content exceeds 5.0%, the grain boundary phase composed of low-strength glass or crystals increases, making the strength more likely to decrease. The ceramic of this embodiment may contain various compounds within a range that does not adversely affect the desired performance, and may contain the remainder, by mass, of one or more selected from Si3N4, BN, and AlN, up to 10.0%. However, it is preferable to avoid SiC because it may significantly degrade the dielectric constant.

[0026] The content of each compound is measured, for example, by the following procedure. For example, in the case of the content of ZrO2, the amounts of Mg, Si, Zr, Al, Y, etc. are determined using an ICP optical emission spectrometer, and the amounts are converted into oxides to determine the content of each compound. The ICP optical emission spectrometer used is a 5110 manufactured by Agilent Technologies. Three measurements were taken, and the amount of each element was determined based on the average value. Other measurement conditions are RF power 1200 W, auxiliary gas flow rate 1 L / min, nebulizer gas flow rate 0.7 L / min, plasma gas flow rate 12 L / min, and Ar gas type.

[0027] (thermal expansion coefficient) The thermal expansion coefficient of the ceramic of this embodiment is 7.5 × 10 -6 / °C or more. This is because even if the wafer is heated to a high temperature, specifically, 125 to 250°C, and a temperature difference occurs between the wafer and the probe guide, the probe guide is likely to thermally expand to the same extent as the wafer. The upper limit of the thermal expansion coefficient is not particularly limited, but is preferably 1.2 × 10 -5 / ℃. The upper limit of the thermal expansion coefficient is 1.1×10 -5 / °C, preferably 1.0 x 10 -5 / °C is preferred.

[0028] The thermal expansion coefficient is measured at a temperature rise rate of 5°C / min using a thermal dilatometer in accordance with JIS R 3251:1990, and the average linear expansion coefficient at -50 to 200°C is calculated.

[0029] (bending strength) In the ceramic of this embodiment, the bending strength is not particularly limited. When used for applications such as a probe guide, for example, it is preferably 200 MPa or more, more preferably 230 MPa or more, and even more preferably 250 MPa or more. The upper limit of the bending strength is not particularly limited, but it is preferably 500 MPa. The bending strength refers to the three-point bending strength and is calculated based on JIS R 1601:2008.

[0030] (Dielectric constant) The dielectric constant of the ceramic of this embodiment is not particularly limited. When used in applications such as a probe guide, the dielectric constant at 25°C and 10 kHz is preferably 9.0 or less. The upper limit of the dielectric constant is preferably 8.5. The lower the dielectric constant, the better, but the practical lower limit is 5.0. The dielectric constant of ceramics is measured and calculated based on JIS R 1641:2007.

[0031] (Application) The ceramic of this embodiment is suitable for a member having a plurality of fine through holes, such as a probe guide component (probe guide) or a socket for package inspection, etc. The probe guide component using the ceramic of this embodiment is suitable for a probe card.

[0032] (Manufacturing method) The ceramic of this embodiment can be stably produced, for example, by the following production method.

[0033] Raw powders of forsterite, ZrO2 and / or Al2O3, and other stabilizers and sintering aids added as needed, as well as powders of sintering aids added as needed, are mixed using a known method such as a ball mill. That is, the powders are mixed in a container with a solvent and ceramic or resin balls with iron cores to form a slurry. In this case, water or alcohol can be used as the solvent. Furthermore, additives such as dispersants and binders can be used as needed.

[0034] The particle size of the forsterite used as the raw material is not particularly limited, but if it is too large, the variation in bending strength will increase, so the average particle size is preferably less than 20 μm, more preferably less than 10 μm, more preferably less than 5 μm, and even more preferably less than 2 μm.

[0035] The particle size of ZrO2 used as a raw material is not particularly limited, but if it is too large, the variation in bending strength will increase, so the average particle size is preferably less than 20 μm, more preferably less than 10 μm, more preferably less than 5 μm, and even more preferably less than 2 μm.

[0036] The particle size of Al2O3 used as a raw material is not particularly limited, but if it is too large, the variation in bending strength will increase, so the average particle size is preferably less than 20 μm, more preferably less than 10 μm, more preferably less than 5 μm, and even more preferably less than 2 μm.

[0037] The resulting slurry is granulated by a known method such as spray drying or a reduced pressure evaporator, i.e., by spray drying with a spray dryer to form granules, or by drying with a reduced pressure evaporator to form powder.

[0038] The resulting powder is sintered under high temperature and pressure using a known method such as hot pressing or HIP (hot isostatic pressing) to obtain a ceramic sintered body. In the case of hot pressing, firing may be performed in a nitrogen atmosphere or pressurized nitrogen. The firing temperature should be in the range of 1200 to 1700°C. If the temperature is too low, sintering will be insufficient, while if the temperature is too high, problems such as elution of oxide components will occur. In order to increase bending strength, the lower the firing temperature within the above range, the better.

[0039] The pressure is preferably in the range of 15 to 35 MPa. In order to increase the thermal expansion coefficient, a higher pressure is preferable within the above range. The duration of pressure application depends on the temperature and dimensions, but is usually about 1 to 3 hours. In the case of HIP, the firing conditions, such as temperature and pressure, can be appropriately set. Other known firing methods, such as atmospheric pressure firing and atmospheric pressure firing, may also be employed.

[0040] The ceramics according to the present invention will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples. [Example]

[0041] The powder raw materials prepared to have the ratios shown in Table 1 were mixed with water, a dispersant, a resin, and ceramic balls, and the resulting slurry was spray-dried with a spray dryer to form granules. The obtained granules were filled into a graphite die, and hot press sintering was performed at a pressure of 30 MPa in a nitrogen atmosphere for 2 hours in the range of 1200 to 1700 °C according to the raw materials, to obtain a test specimen with a length of 150 × width of 150 × thickness of 30 mm. Test pieces were taken from the obtained test specimen and various tests were conducted. Also, for the obtained test pieces, the content was measured using an ICP emission spectroscopic analyzer.

[0042] <Each content> For any of the compounds, the amounts of Mg, Si, Zr, Al, Y, etc. were specified, and the contents of the respective compounds were obtained by converting them to oxides. In addition, the contents of the stabilizer and the sintering aid were also taken as the values obtained by converting the amounts of the respective elements contained to oxides.

[0043] An ICP emission spectroscopic analyzer, Agilent Technologies 5110, was used, and the number of measurements was set to 3 times. Based on the average value, the amounts of each element were specified. Other measurement conditions were RF power of 1200 W, auxiliary gas flow rate of 1 L / min, nebulizer gas flow rate of 0.7 L / min, plasma gas flow rate of 12 L / min, and the type of gas was Ar. Hereinafter, the components obtained in this way were described in Table 1.

[0044] <Crystal structure of ZrO2> Peak intensities were measured by XRD to determine the peak intensities of each crystalline phase (monoclinic, cubic, and tetragonal) on the (200) plane of ZrO2. The monoclinic peak was at 34.2°, the cubic peak at 34.9°, and the tetragonal peak at 35.3°. When the sum of the above three peak intensities was taken as 100%, the cubic peak intensity was determined to be 80% or higher, indicating that the ZrO2 crystal structure was cubic. To eliminate noise during measurement, a baseline was drawn in the diffraction angle 2θ range of 32 to 38° to determine the above peak intensities. An XRD manufactured by BRUKER was used for the measurements. It was confirmed that the crystal structures of ZrO2 in Examples 1 to 4 and Comparative Example 1 were all cubic.

[0045] Each test material was used to examine the following properties.

[0046] <Thermal expansion coefficient> The thermal expansion coefficient of the ceramics was measured using a thermal dilatometer at a temperature increase rate of 5° C. / min, and the average linear expansion coefficient was calculated from the temperature range of −50 to 200° C. The measurement was carried out in accordance with JIS R 3251:1990.

[0047] <Bending strength> The three-point bending strength of the ceramics was determined based on JIS R 1601:2008.

[0048] <Relative density> The relative density of ceramics was calculated by determining the bulk density based on JIS C 2141: 1992 and dividing the bulk density by the theoretical density. A relative density of 90% or more was considered good.

[0049] <Dielectric constant> The dielectric constant of the ceramics was determined at 25°C and 10 kHz based on JIS R 1641:2007.

[0050] [Table 1]

[0051] Examples 1 to 6, which satisfy the requirements of this embodiment, have a thermal expansion coefficient of 7.5 × 10 -6 / °C or more, and the dielectric constant at 25°C and 10 kHz was 9.0 or less. On the other hand, Comparative Examples 1, 3, and 6 to 8, which do not satisfy the requirements of this embodiment, were poor in at least one of the thermal expansion coefficient and the dielectric constant. In Comparative Example 2, the crystalline phase of ZrO2 was tetragonal. Comparative Examples 4 and 5 were poor in bending strength.

[0052] The ceramics of Example 1 and Comparative Example 2 were held at 150°C for 100 hours, then naturally cooled to room temperature, and the dimensional change (change per 100 mm) before and after holding at 150°C was measured. The dimensional change of the ceramics of Example 1 was 5 μm, while the dimensional change of the ceramics of Comparative Example 2 was 135 μm. [Explanation of symbols]

[0053] 10. Probe Card 11. Probe 12. Probe guide (probe guide part) 12a.Through hole 13. Silicon wafer 14. IC chip

Claims

1. In mass%, 2MgO.SiO ２ : 50.0 to 90.0% ZrO ２ : 7.0 to 14.0% and Al ２ O ３ : 10.0 to 50.0%, or ZrO ２ : 14.0% or less and Al ２ O ３ : Both 50.0% or less, total 8.0% or more, Y ２ O ３ , CaO, CeO ２ and HfO ２ One or more selected from: 3.0 to 15.0%; Including, The ZrO ２ The crystal structure of ceramics is cubic.

2. Furthermore, TiO ２ , SiO ２ , MoO ３ , Ta ２ O ５ , Yb ２ O ３ , LaO and B ２ O ３ The ceramic according to claim 1, containing 0 to 5.0% of one or more selected from the following.

3. Thermal expansion coefficient is 7.5 x 10 －６ The ceramic according to claim 1 or 2, wherein the temperature is 1000 K / °C or higher.

4. 3. The ceramic according to claim 1, wherein the dielectric constant at 25°C and 10 kHz is 9.0 or less.

5. A probe guide component comprising the ceramic according to claim 1 or 2.

6. A probe card comprising the probe guide component according to claim 5 .

7. A package inspection socket comprising the ceramic according to claim 1 or 2.

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