Silicon nitride composite material and probe guide part

Abstract

The present application provides a silicon nitride composite material and a probe guide member, which stably have a thermal expansion coefficient equivalent to that of a silicon wafer and high strength. Specifically, the silicon nitride composite material of the present application contains 35 mass% or more and 70 mass% or less of Si3N4, 25 mass% or more and 60 mass% or less of ZrO2, and 0.5 mass% or more and less than 5 mass% of one or more selected from the group consisting of MgO, SiO2, Al2O3, and Y2O3, and a peak intensity ratio Iβ / (Iα+Iβ) is 0.05 or more and 0.80 or less, when a peak intensity of an (210) plane of αSi3N4 in powder X-ray diffraction is Iα and a peak intensity of an (210) plane of βSi3N4 is Iβ. The probe guide member of the present application has a plate-shaped body portion using the silicon nitride composite material, and a plurality of through-holes and / or slits through which a probe passes through the body portion.

Description

Technical Field

[0001] This invention relates to silicon nitride composite materials and probe guiding components. Background Technology

[0002] IC chips or LSI chips are fabricated on a single silicon wafer, with each chip then cut into pieces for use. Before each chip is cut, a probe card is used to check whether each chip is defective. For example, as disclosed in Patent Document 1, the probe card structure includes: a substrate with a probe mounted at one end; and a guide plate (probe guiding component) that slides freely to guide the probe. By passing the probe through a guide hole in the guide plate, the tip of the probe can accurately contact the pad (electrode) of the IC chip or LSI chip formed on the silicon wafer. Then, an electrical signal is applied in this contact state, the electrical signal output from the chip is analyzed, and the presence or absence of a defective chip is determined. This inspection is often performed at, for example, room temperature or high temperature environments (e.g., 80–150°C). Therefore, the guide plate (probe guiding component) for such a probe card is required to have a coefficient of thermal expansion similar to that of the silicon wafer within a temperature range from room temperature to approximately 200°C.

[0003] On the other hand, the probe guiding parts are also required to have mechanical strength (bending strength) to withstand probe loads, and the demand for higher strength has been increasing in recent years. Under these circumstances, Patent Document 2 discloses that, in order to obtain a ceramic with a coefficient of thermal expansion similar to that of a silicon wafer and high strength, it is effective to composite a high-expansion ceramic, ZrO2, into a high-strength ceramic, Si3N4.

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-215163

[0006] Patent Document 2: International Publication No. 2019 / 093370 Summary of the Invention

[0007] Based on the disclosure of Patent Document 2, the inventors have prepared silicon nitride composite materials containing ZrO2 in Si3N4 under various conditions. However, when evaluating their thermal expansion and strength properties, the expected properties were not fully realized due to the preparation conditions and other factors.

[0008] Therefore, the technical problem to be solved by the present invention is to provide a silicon nitride composite material and probe guiding component that stably possesses the same coefficient of thermal expansion and high strength as silicon wafers.

[0009] To address the aforementioned issues, the inventors, based on repeated experiments and research, discovered that in order to ensure that the silicon nitride composite material containing ZrO2 in Si3N4 stably possesses the same coefficient of thermal expansion and high strength as silicon wafers, it is not only necessary to control the content of each component such as Si3N4 and ZrO2, but also, importantly, to control the microstructure of the silicon nitride composite material. Furthermore, it was found that, while detailed later, it is crucial to ensure that the peak intensity ratio Iβ / (Iα+Iβ) is within a specified range when using the peak intensity of the (210) plane of αSi3N4 obtained by powder X-ray diffraction as Iα and the peak intensity of the (210) plane of βSi3N4 as Iβ.

[0010] That is, according to one aspect of the present invention, the following silicon nitride composite material can be provided.

[0011] Include:

[0012] Si3N4 with a mass percentage of 35% to 70%;

[0013] ZrO2 of 25% to 60% by mass;

[0014] and a total of 0.5% by mass and less than 5% by mass of one or more selected from MgO, SiO2, Al2O3 and Y2O3.

[0015] A silicon nitride composite material in which the peak intensity of the (210) plane of αSi3N4 obtained by powder X-ray diffraction is taken as Iα and the peak intensity of the (210) plane of βSi3N4 is taken as Iβ, and the peak intensity ratio Iβ / (Iα+Iβ) is 0.05 to 0.80.

[0016] Furthermore, according to other aspects of the present invention, a probe guiding component for guiding probe cards can be provided, characterized in that it comprises a plate-shaped body portion using the silicon nitride composite material of the present invention described above, and a plurality of through holes and / or slits through the probe in the body portion.

[0017] According to the present invention, a silicon nitride composite material and a probe guiding component that stably possess the same coefficient of thermal expansion as a silicon wafer and high strength can be provided. Attached Figure Description

[0018] Figure 1 These are powder X-ray diffraction intensity data of the silicon nitride composite material involved in one embodiment of the present invention (Example 4 in Table 1).

[0019] Figure 2 This is a cross-sectional SEM image of the silicon nitride composite material involved in one embodiment of the present invention (Example 8 in Table 1).

[0020] Figure 3 These are cross-sectional SEM images of the silicon nitride composite material involved in the comparative example of the present invention (Comparative Example 9 in Table 1). Detailed Implementation

[0021] The silicon nitride composite material of the present invention contains highly expandable ZrO2 in high-strength Si3N4 as the main component, and contains 35% to 70% by mass of Si3N4 and 25% to 60% by mass of ZrO2.

[0022] When the Si3N4 content is less than 35% by mass, it is difficult to obtain high strength. On the other hand, when the Si3N4 content exceeds 70% by mass, it is difficult to obtain a coefficient of thermal expansion similar to that of silicon wafers. Preferably, the Si3N4 content is 50% by mass or more and 60% by mass or less.

[0023] Furthermore, when the ZrO2 content is less than 25% by mass, a high coefficient of thermal expansion cannot be obtained, and it is difficult to achieve the same level of thermal expansion as silicon wafers. When the ZrO2 content exceeds 60% by mass, the coefficient of thermal expansion becomes too high, making it difficult to achieve the same level of thermal expansion as silicon wafers. Preferably, the ZrO2 content is between 35% and 45% by mass.

[0024] Furthermore, the combined content of Si3N4 and ZrO2 is preferably 90% by mass or more and 99.5% by mass or less, and more preferably 90% by mass or more and 98% by mass or less.

[0025] One characteristic of the silicon nitride composite material of the present invention is that, when the peak intensity of the (210) plane of αSi3N4 obtained by powder X-ray diffraction is Iα and the peak intensity of the (210) plane of βSi3N4 is Iβ, the peak intensity ratio: Iβ / (Iα+Iβ) (hereinafter simply referred to as "peak intensity ratio") is 0.05 to 0.80 or less. When the peak intensity ratio exceeds 0.8, even if the ZrO2 content is within the above-specified range, the coefficient of thermal expansion will not increase to the specified value. Furthermore, when the peak intensity ratio is less than 0.05, the mechanical strength decreases because the strength of βSi3N4, which is higher than that of αSi3N4, decreases. The reason for this will be explained below.

[0026] In silicon nitride composites, thermal expansion characteristics can be controlled not only by adjusting the content of components such as Si3N4 and ZrO2, but also by controlling the microstructure. Furthermore, the inherent high strength of silicon nitride also depends on its microstructure. The inventors have discovered that the peak intensity ratio of silicon nitride powder X-ray diffraction is crucial for accurate control.

[0027] As the raw material for silicon nitride composites, silicon nitride primarily uses αSi3N4 as the raw material, and zirconium oxide primarily uses ZrO2 stabilized by Y2O3, etc., and they are mixed in the same manner as in conventional ceramic manufacturing, and the mixed molded body is sintered. During this sintering process, ceramic particles grow into grains. Silicon nitride and zirconium oxide are the same in this respect. Furthermore, at this time, the crystal structure of silicon nitride transforms from αSi3N4 to βSi3N4. This βSi3N4 is a needle-like crystal with a high aspect ratio.

[0028] When zirconia, with its high coefficient of thermal expansion, and silicon nitride, with its low coefficient of thermal expansion, form a composite structure during sintering, their behavior during the next cooling process varies depending on their grain size. During grain growth in both materials during sintering, silicon nitride undergoes a greater transformation to βSi3N4, and the grain sizes of both αSi3N4 and zirconia also increase. However, during the transformation from α-type to β-type, αSi3N4 decreases; that is, αSi3N4 is absorbed by βSi3N4. At this point, the αSi3N4 present between zirconia particles decreases, and relatively speaking, the amount of zirconia particles bonded to adjacent zirconia particles increases. In this state, sintering ends, and during cooling, the individual particles shrink. Zirconia shrinks more than silicon nitride due to its material properties. Moreover, tensile stress acts on the bonded zirconia as it shrinks, leading to the formation of gaps and cracks between zirconia-silicon nitride or between zirconia-zirconia particles.

[0029] Although the silicon nitride and zirconium oxide expand together when the silicon nitride composite material obtained under these conditions is heated, the expansion of zirconium oxide is absorbed by the aforementioned cracks and does not contribute to an increase in overall thermal expansion. Therefore, the value remains below the theoretical coefficient of thermal expansion.

[0030] Conversely, when no grain growth occurs in either material during sintering, the amount of silicon nitride transforming into βSi3N4 is less, resulting in αSi3N4 with a grain size similar to that of zirconium oxide, and a state where βSi3N4 exists to some extent in the interwoven matrix of both materials. In this state, sintering is completed, and during cooling, due to the smaller zirconium oxide particles, less thermal stress is generated, thus preventing the aforementioned cracks.

[0031] When the silicon nitride composite material obtained under these conditions is heated, the silicon nitride and zirconium oxide expand together, and the coefficient of thermal expansion is higher than that of the silicon nitride monomer material.

[0032] The inventors have discovered that, as a control parameter for the microstructure of such silicon nitride composite materials, the peak strength ratio is preferably 0.05 or more and 0.80 or less.

[0033] When the peak intensity ratio exceeds 0.80, there is more βSi3N4 and less αSi3N4, meaning that a lot of αSi3N4 undergoes β-oxidation. Although αSi3N4 is also present, its quantity is small, resulting in a zirconia grain growth and bonding structure, leading to a smaller increase in the coefficient of thermal expansion. Therefore, it is difficult to obtain the same coefficient of thermal expansion as silicon wafers.

[0034] Furthermore, even as a condition for maintaining the high strength of silicon nitride ceramics, the peak strength ratio has an impact. Specifically, the greater the amount of β-formed needle-like crystals (βSi3N4) of αSi3N4, the higher the strength. Therefore, when the peak strength ratio is less than 0.05, due to the small amount of β-formed needle-like crystals (βSi3N4) of αSi3N4, it is difficult for silicon nitride to maintain the high strength of the ceramic.

[0035] In addition, a peak intensity ratio of 0.25 or higher and 0.65 or lower is preferred.

[0036] Since silicon nitride is a material with strong covalent bonds, it cannot be sintered in a monomeric state. Therefore, oxides are usually added, and sintering is performed in a liquid phase. The oxides act as sintering aids that readily generate a liquid phase during sintering. In this invention, only a small amount of such oxide is needed, and one or more selected from MgO, SiO2, Al2O3, and Y2O3 can be used. Furthermore, although the oxide film on the surface of silicon nitride particles, i.e., SiO2, can also serve as a SiO2 source, silicon oxide, which can also act as a SiO2 source, can be added separately.

[0037] Although the liquid phase is primarily amorphous after sintering, some crystallization occurs. Furthermore, there is a possibility that some zirconium oxide may dissolve into the liquid phase. After sintering, these phases exist at or near the grain boundaries surrounding the silicon nitride particles. The content of the aforementioned oxide components is a total of 0.5% by mass or more but less than 5% by mass. When the content is less than 0.5% by mass, it is impossible to obtain a liquid phase that controls only the crystalline phase of silicon nitride in sintered silicon nitride. On the other hand, when the content is 5% by mass or more, zirconium oxide particles easily sinter together, and for the reasons mentioned above, cracks may appear between zirconium oxide and silicon nitride or between zirconium oxide particles, resulting in a gapped state. The expansion of zirconium oxide is absorbed by these cracks, failing to contribute to an increase in overall thermal expansion. Furthermore, there is a possibility that other oxides may form, making it impossible to maintain the inherent high strength of silicon nitride.

[0038] In addition, it is preferable that the content of the above-mentioned oxide components is more than 1% by mass and less than 3% by mass.

[0039] Although the silicon nitride composite material of the present invention, as described above, uses αSi3N4 as the basic silicon nitride and ZrO2 stabilized by Y2O3 as the basic zirconium oxide, and can be obtained by mixing and sintering the molded body in the same manner as conventional ceramic manufacturing, βSi3N4 can also be used if the quantity is small. Furthermore, cubic ZrO2 stabilized by Y2O3 is preferred, but partially cubic ZrO2 stabilized by Y2O3 can also be used. Additionally, although the ZrO2 stabilized by Y2O3 contains stabilizing components such as Y2O3, the silicon nitride composite material of the present invention also includes the content of stabilizing components such as Y2O3 in the ZrO2 content. In other words, the content of stabilizing components such as Y2O3 contained in the ZrO2 is not included in the content of the oxide components that function as sintering aids as described above.

[0040] In the silicon nitride composite material of the present invention, the content of each of the above-mentioned components can be basically determined by ICP-luminescence spectrophotometry. Furthermore, although ICP-luminescence spectrophotometry cannot distinguish between stabilizing components such as Y₂O₃ contained in the ZrO₂ raw material and oxide components that function as sintering aids, since the content of stabilizing components such as Y₂O₃ contained in the ZrO₂ raw material can be determined in advance, the content of oxide components that function as sintering aids can be determined by subtracting the content of stabilizing components such as Y₂O₃ contained in the ZrO₂ raw material from the value determined by ICP-luminescence spectrophotometry.

[0041] Although other components besides those mentioned above may include Si2N2O, silicon oxynitride, and Y3Al5O, the silicon nitride composite material of the present invention may contain Si2N2O, silicon oxynitride, and Y3Al5O. 12 YAG (yttrium aluminum garnet), R2SiO4 (R is Mg, Fe, Mn, Ca, etc.), and forsterite, etc., but preferably their content is less than 9% by mass in total.

[0042] While one of the characteristics of the silicon nitride composite material of the present invention is that the peak strength ratio is 0.05 or more and 0.80 or less, as described above, this peak strength ratio can be controlled by using the sintering temperature. Specifically, as shown in the embodiments described later, by setting the sintering temperature to 1500°C or more and 1670°C or less, the peak strength ratio can be made to be 0.05 or more and 0.80 or less.

[0043] As described above, by keeping the content of each component and the peak intensity ratio within a specified range, a silicon nitride composite material with a stable coefficient of thermal expansion and high strength comparable to that of a silicon wafer can be obtained. Specifically, as shown in the examples described later, a coefficient of thermal expansion of 3 × 10⁻⁶ can be stably obtained from room temperature to 200°C.-6 / ℃ or above 6×10 -6 Thermal expansion characteristics below / ℃ and strength characteristics with a bending strength of 400MPa or more.

[0044] The silicon nitride composite material of the present invention can be appropriately used as the body portion of a probe guiding part for guiding probes of a probe card. That is, the probe guiding part of the present invention has a plate-shaped body portion using the silicon nitride composite material of the present invention and a plurality of through holes and / or slits through which probes pass.

[0045] Furthermore, as an application requiring the same performance as a probe guide component that guides the probes of a probe card, the silicon nitride composite material of the present invention can also be used for encapsulating inspection sockets and the like.

[0046] Example

[0047] To confirm the effectiveness of the present invention, α-Si3N4 powder with modified proportions, stabilized ZrO2 powder, one or more oxide powders selected from MgO, Y2O3, Al2O3, and SiO2, were mixed with water, dispersant, forming aid, and ceramic balls in a ball mill. The resulting slurry was then spray-dried to form granules. The granules were then stamped into a 40×30mm diameter body at a pressure of 140MPa, and the forming aid was degreased. The degreased body was then placed in a graphite die and hot-pressed at 1450℃ to 1700℃ for 2 hours under a nitrogen atmosphere while applying a pressure of 30MPa, resulting in a test material with dimensions of 40×40×15mm. Test pieces were then selected from the obtained test material, and the peak strength ratio, coefficient of thermal expansion, and flexural strength were evaluated. A comprehensive evaluation was then conducted based on these evaluation results.

[0048] Table 1 shows the composition and evaluation results of the silicon nitride composite materials involved in the embodiments and comparative examples of the present invention. Additionally, in Table 1, as mentioned above, "other components" are Si2N2O: silicon oxynitride, Y3Al5O 12 YAG (yttrium aluminum garnet), R2SiO4 (R is Mg, Fe, Mn, Ca, etc.): forsterite, etc.

[0049] Table 1

[0050]

[0051] The evaluation of peak strength ratio, coefficient of thermal expansion and flexural strength, as well as the comprehensive evaluation, shall be carried out in accordance with the following principles.

[0052] (Peak intensity ratio)

[0053] exist Figure 1 As an example of powder X-ray diffraction, the powder X-ray diffraction intensity data of Example 4 in Table 1 are shown. Based on such powder X-ray diffraction intensity data, the peak intensity of the (210) plane of αSi3N4: Iα and the peak intensity of the (210) plane of βSi3N4: Iβ were obtained, and the peak intensity ratio: Iβ / (Iα+Iβ) was calculated.

[0054] (Coefficient of thermal expansion)

[0055] For each example of test specimens, the coefficient of thermal expansion from room temperature to 200°C was determined according to JIS (Japanese Industrial Standard) R1618. Coefficient of thermal expansion (unit: 10⁻⁶) -6 The rating for ( / ℃) is as follows: 3.5 or above and 5 or below is ◎ (excellent); 3 or above and less than 3.5 or more than 5 and less than 6 is 〇 (good); less than 3 is × (low) (poor); and more than 6 is × (high) (poor).

[0056] (Flexural strength)

[0057] For each example test piece, the four-point bending strength was determined according to JIS (Japanese Industrial Standard) R1601. The bending strength (unit: MPa) was evaluated as follows: 600 or above was ◎ (excellent), 400 or above but less than 600 was 〇 (good), and less than 400 was × (poor).

[0058] (Overall Evaluation)

[0059] The case where both the coefficient of thermal expansion and the flexural strength are rated as ◎ (excellent) is considered as ◎ (excellent); the case where at least one of the ratings is 〇 (good) and there is no × (poor) rating is considered as 〇 (good); and the case where at least one of the ratings is × (poor) is considered as × (poor).

[0060] In Table 1, the composition (content of each component) and peak intensity ratio of Examples 1 to 12 are all within the range of the present invention, and the overall evaluation is ◎ (excellent) or 0 (good), thus obtaining good results. Among them, Examples 7 to 12, whose composition and peak intensity ratio are both within the preferred range, are rated ◎ (excellent), and particularly good results can be obtained.

[0061] in addition, Figure 2 The image shows a cross-sectional SEM photograph of the silicon nitride composite material involved in Example 8. It can be seen that needle-like crystals, namely βSi3N4, exist in a heterogeneous matrix on which ZrO2 and αSi3N4 of the same grain size are interwoven.

[0062] In Table 1, Comparative Example 1 is an example of low Si3N4 content and low peak strength. Its flexural strength is rated as × (poor). Furthermore, in Comparative Example 1, the ZrO2 content is also relatively high, and its coefficient of thermal expansion is rated as "× (high)".

[0063] On the other hand, Comparative Example 2 is an example of excessively high Si3N4 content and peak intensity. The coefficient of thermal expansion is rated as "× (low)".

[0064] Comparative Example 3 is an example of excessively low ZrO2 content. Its coefficient of thermal expansion is rated as "× (low)". Comparative Example 4 is an example of excessively high ZrO2 content. Its coefficient of thermal expansion is rated as "× (high)".

[0065] Comparative Example 5 is an example that does not contain oxide components (MgO content) and has an excessively low peak strength. Its flexural strength is rated × (poor).

[0066] Comparative Example 6 is an example of excessively high oxide content (MgO content). This also resulted in a flexural strength rating of × (poor).

[0067] Comparative Example 7 is an example of excessively high oxide content (MgO content) and peak strength ratio. The flexural strength is rated × (poor), and the coefficient of thermal expansion is rated × (low).

[0068] Comparative Examples 8 and 9 are examples of excessively high peak strength ratios. Their coefficients of thermal expansion are both rated "× (low)". Comparative Example 10 is an example of excessively low peak strength ratios. Its flexural strength is rated "× (poor)".

[0069] in addition, Figure 3 The image shows a cross-sectional SEM image of the silicon nitride composite material involved in Comparative Example 9. It can be seen that αSi3N4 is almost entirely transformed into βSi3N4 and grows together with ZrO2.

Claims

1. A silicon nitride composite material, characterized in that, Include: Si3N4 with a mass percentage of 35% to 70%; ZrO2 of 25% to 60% by mass; and a total of 0.5% by mass and less than 5% by mass of one or more selected from MgO, SiO2, Al2O3 and Y2O3. When the peak intensity of the 210 plane of αSi3N4 obtained by powder X-ray diffraction is taken as Iα and the peak intensity of the 210 plane of βSi3N4 is taken as Iβ, the peak intensity ratio: Iβ / (Iα+Iβ) is above 0.05 and below 0.

80.

2. A probe guide component for guiding probes of a probe card, characterized in that, It has a plate-shaped body portion using the silicon nitride composite material of claim 1 and a plurality of through holes and / or slits through the probe in the body portion.

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