Composition for producing silicon nitride substrate and silicon nitride substrate produced therewith

Abstract

A composition for producing a silicon nitride substrate is provided. The composition for producing a silicon nitride substrate according to one embodiment of the present invention comprises a mixed powder containing a silicon-based powder and a nitride-based sintering aid, and the mixed powder is embodied so that the particle distribution coefficient of variation (CV value) is 65 to 86%. This allows the sintered body to exhibit excellent density and thermal conductivity, as well as excellent mechanical strength such as bending strength and wear resistance, while also exhibiting uniform physical properties.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to a composition for producing a silicon nitride substrate, and more particularly to a composition for producing a silicon nitride substrate and a silicon nitride substrate produced therefrom.

[0002] [Background technology] Silicon nitride has been the subject of vigorous research into its industrial applications due to its excellent mechanical properties, oxidation resistance, and chemical stability. However, its manufacturing costs are higher than those of other materials, such as metals, due to the need for expensive raw material powder and high sintering temperatures. Furthermore, its relatively high sintering shrinkage after sintering necessitates additional surface processing to improve the dimensional accuracy of manufactured parts. Silicon nitride's high strength, hardness, and fracture toughness require expensive equipment, such as diamond abrasives, for the processing process, resulting in additional manufacturing costs. These high manufacturing costs, along with its lower reliability compared to metals, have been the most significant factors inhibiting the industrial use of silicon nitride parts.

[0003] Reaction sintering has been attracting attention as a process to improve these shortcomings of silicon nitride. The reaction sintering method for silicon nitride uses high-purity silicon powder as a starting material. That is, after forming silicon into a desired shape, it is slowly heated in a nitrogen atmosphere at 1350-1450°C for several hours, whereby the silicon reacts with the nitrogen to form silicon nitride.

[0004] During the nitriding process, nitrogen is added to the silicon structure, increasing both the mass and volume, but there is no significant difference in the size of the compact. This is because the volume expansion proceeds in the direction of filling the pores of the compact. As a result, the relative density of the compact increases from around 60% to over 70%, and the sintering shrinkage rate also decreases.

[0005] However, silicon nitride molded bodies produced by the reaction sintering method generally have the problem that they require higher sintering temperatures than those produced by processes using existing fine silicon nitride raw material powders, and the mechanical properties of the manufactured products are also poor. Additionally, conventional silicon nitride molded bodies have the problem of not being able to simultaneously exhibit all of the effects of excellent density and thermal conductivity, excellent mechanical strength such as bending strength and wear resistance, and uniform physical properties.

[0006] Therefore, research into the production of silicon nitride substrates that are excellent in density and thermal conductivity, and in mechanical strength such as bending strength and abrasion resistance, while also exhibiting uniform physical properties, is urgently needed. [Summary of the Invention] [Problem to be solved by the invention] The present invention has been devised to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a composition for producing a silicon nitride substrate, which provides a sintered body with excellent density and thermal conductivity, and excellent mechanical strength such as bending strength and abrasion resistance, while also exhibiting uniform physical properties, and a silicon nitride substrate produced using the composition.

[0007] [Means for solving the problem] In order to solve the above-mentioned problems, the present invention provides a composition for producing a silicon nitride substrate, which comprises a mixed powder containing a silicon-based powder and a nitride-based sintering aid, and the mixed powder has a particle distribution coefficient of variation (CV value) of 65 to 86%.

[0008] According to one embodiment of the present invention, the mixed powder may have an average particle size of 0.5 to 4 μm. The mixed powder may have a ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of 1:1.8 to 18.5.

[0009] The mixed powder may have a particle size distribution D10 of 0.15 to 0.55 μm, a particle size distribution D50 of 1 to 2.7 μm, and a particle size distribution D90 of 3.8 to 6.2 μm. The silicon-based powder may include a first silicon-based powder and a second silicon-based powder having an average particle size smaller than that of the first silicon-based powder.

[0010] Additionally, the content of the first silicon-based powder may be greater than the content of the second silicon-based powder. Furthermore, the second silicon-based powder may have a larger particle distribution coefficient of variation (CV value) than the first silicon-based powder.

[0011] The first silicon-based powder may have an average particle size of 4.1 to 6.6 μm, and the second silicon-based powder may have an average particle size of 1.1 to 3.7 μm. The silicon-based powder may contain the first silicon-based powder and the second silicon-based powder in a weight ratio of 1:0.4 to 0.7.

[0012] The first silicon-based powder may have a particle size distribution D10 of 2.2 to 3.8 μm, a particle size distribution D50 of 4.1 to 6.5 μm, and a particle size distribution D90 of 6.7 to 9.1 μm, and the second silicon-based powder may have a particle size distribution D10 of 0.4 to 0.95 μm, a particle size distribution D50 of 1.1 to 2.8 μm, and a particle size distribution D90 of 3 to 6.6 μm.

[0013] The first silicon-based powder may have a particle distribution coefficient of variation (CV value) of 25 to 45%, and the second silicon-based powder may have a particle distribution coefficient of variation (CV value) of 56 to 77%. The silicon-based powder may be contained in an amount of 80 to 94% by weight based on the total weight of the mixed powder.

[0014] The nitride-based sintering aid may include at least one of MgSiN2 and Y2Si4N6C. The MgSiN2 may have an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm, and the Y2Si4N6C may have an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm.

[0015] In addition, the content of MgSiN2 may be the smallest among the total content of the nitride-based sintering aids, and the coefficient of variation (CV value) of particle distribution of MgSiN2 may be the largest among the nitride-based sintering aids. Furthermore, the MgSiN2 may have a particle distribution coefficient of variation (CV value) of 55 to 75%, and the Y2Si4N6C may have a particle distribution coefficient of variation (CV value) of 35 to 55%.

[0016] The nitride-based sintering aid may contain the MgSiN2 and Y2Si4N6C in a weight ratio of 1:1.2 to 2.6. The present invention also provides a silicon nitride substrate obtained by nitriding and sintering the above-mentioned composition for producing a silicon nitride substrate.

[0017] Meanwhile, the terms "particle size distribution D10," "particle size distribution D50," and "particle size distribution D90" used herein refer to particle sizes at 10%, 50%, and 90% cumulative levels, respectively, in a volume cumulative particle size distribution. Specifically, in a graph (volume-based particle size distribution) with particle size on the horizontal axis and volume cumulative frequency from the smallest particle size on the vertical axis, D10, D50, and D90 are the particle sizes of particles whose volume percentage cumulative values ​​from the smallest particle size to the volume cumulative value (100%) of all particles correspond to 10%, 50%, and 90%, respectively. The volume cumulative particle size distribution can be measured using a laser diffraction / scattering particle size distribution analyzer.

[0018] [Effects of the invention] The composition for producing a silicon nitride substrate of the present invention and the silicon nitride substrate produced therefrom exhibit excellent sintered body density and thermal conductivity, as well as excellent mechanical strength such as bending strength and abrasion resistance, while also exhibiting uniform physical properties. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0020] The composition for producing a silicon nitride substrate according to the present invention comprises a mixed powder containing a silicon-based powder and a nitride-based sintering aid, and the mixed powder is embodied so that the coefficient of variation (CV value) of particle distribution is 65 to 86%.

[0021] As described above, the mixed powder contained in the composition for producing a silicon nitride substrate of the present invention may have a particle distribution coefficient of variation (CV value) of 65 to 86%, and preferably a particle distribution coefficient of variation (CV value) of 67 to 84%. If the particle distribution coefficient of variation of the mixed powder is less than 65%, the density, thermal conductivity, and mechanical strength may decrease, and if the particle distribution coefficient of variation of the mixed powder is more than 86%, the density, thermal conductivity, and mechanical strength may decrease.

[0022] At this time, the particle distribution coefficient of variation (CV value) can be calculated using the following calculation formula 1. [Formula 1] Coefficient of variation of particle distribution (CV value, %) = (standard deviation of particle diameter (σ) / average particle diameter (D n ))×100(%) The mixed powder may have an average particle size of 0.5 to 4 μm, preferably 1 to 3.5 μm. If the average particle size of the mixed powder is less than 0.5 μm, the denseness, thermal conductivity, and mechanical strength may decrease, and if the average particle size exceeds 4 μm, the denseness, thermal conductivity, and mechanical strength may decrease.

[0023] The mixed powder may have a ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of 1:1.8 to 18.5, and preferably a ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of 1:2.35 to 13. If the ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of the mixed powder is less than 1:1.8, the denseness, thermal conductivity, and mechanical strength may decrease, and if the ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of the mixed powder is more than 1:18.5, the denseness, thermal conductivity, and mechanical strength may decrease.

[0024] The mixed powder may have a particle size distribution D10 of 0.15 to 0.55 μm, a particle size distribution D50 of 1 to 2.7 μm, and a particle size distribution D90 of 3.8 to 6.2 μm. Preferably, the mixed powder may have a particle size distribution D10 of 0.2 to 0.5 μm, a particle size distribution D50 of 1.2 to 2.5 μm, and a particle size distribution D90 of 4.0 to 6.0 μm. If the particle size distribution D10 of the mixed powder is less than 0.15 μm, the denseness, thermal conductivity, and mechanical strength may be reduced. If the particle size distribution D10 is greater than 0.55 μm, the mechanical strength may be reduced. If the particle size distribution D50 of the mixed powder is less than 1 μm, the denseness, thermal conductivity, and mechanical strength may be reduced. If the particle size distribution D50 is greater than 2.7 μm, the mechanical strength may be reduced. If the particle size distribution D90 of the mixed powder is less than 3.8 μm, the density, thermal conductivity, and mechanical strength may decrease, and if the particle size distribution D10 exceeds 6.2 μm, the mechanical strength may decrease.

[0025] On the other hand, since the silicon-based powder described below accounts for most of the total weight of the mixed powder, the particle size distribution D10 of the mixed powder may be significantly lower than the particle size distribution D10 of the silicon-based powder. Despite this tendency, the particle size distribution D10 of the mixed powder may satisfy the above range, which may be more advantageous in achieving the object of the present invention.

[0026] Each component of the composition for producing a silicon nitride substrate of the present invention will be described below. First, the silicon-based powder will be described. The silicon-based powder serves as a main component in the composition for producing a silicon nitride substrate according to the present invention.

[0027] The silicon-based powder may be a compound in which silicon and other elements are combined, such as silicon oxide and / or silicon nitride, but is preferably silicon powder, which may be more advantageous for achieving the objectives of the present invention.

[0028] Meanwhile, the silicon-based powder may include a first silicon-based powder and a second silicon-based powder having an average particle size smaller than that of the first silicon-based powder. The first silicon-based powder may have an average particle size of 4.1 to 6.6 μm, preferably 4.3 to 6.4 μm, and the second silicon-based powder may have an average particle size of 1.1 to 3.7 μm, preferably 1.3 to 3.5 μm. If the average particle size of the first silicon-based powder is less than 4.1 μm, the density, thermal conductivity, and mechanical strength may decrease, and if it exceeds 6.6 μm, the mechanical strength may decrease. Furthermore, if the average particle size of the second silicon-based powder is less than 1.1 μm, the density, thermal conductivity, and mechanical strength may decrease, and if it exceeds 3.7 μm, the mechanical strength may decrease.

[0029] The first silicon-based powder may have a particle size distribution D10 of 2.2 to 3.8 μm, a particle size distribution D50 of 4.1 to 6.5 μm, and a particle size distribution D90 of 6.7 to 9.1 μm, preferably a particle size distribution D10 of 2.3 to 3.6 μm, a particle size distribution D50 of 4.3 to 6.3 μm, and a particle size distribution D90 of 6.9 to 8.9 μm, and the second silicon-based powder may have a particle size distribution D10 of 0.4 to 0.95 μm, a particle size distribution D50 of 1.1 to 2.8 μm, and a particle size distribution D90 of 3 to 6.6 μm, preferably a particle size distribution D10 of 0.45 to 0.8 μm, a particle size distribution D50 of 1.3 to 2.6 μm, and a particle size distribution D90 of 3.2 to 6.4 μm.

[0030] If the D10 of the first silicon-based powder is less than 2.2 μm, the density, thermal conductivity, and mechanical strength may decrease; if the D10 is more than 3.8 μm, the mechanical strength may decrease; if the D50 is less than 4.1 μm, the density, thermal conductivity, and mechanical strength may decrease; if the D50 is more than 6.5 μm, the mechanical strength may decrease; if the D90 is less than 6.7 μm, the density, thermal conductivity, and mechanical strength may decrease; and if the D90 is more than 9.1 μm, the mechanical strength may decrease. Furthermore, if the D10 of the second silicon-based powder is less than 0.4 μm, the density, thermal conductivity, and mechanical strength may decrease; if the D10 is more than 0.95 μm, the mechanical strength may decrease; if the D50 is less than 1.1 μm, the density, thermal conductivity, and mechanical strength may decrease; if the D50 is more than 2.8 μm, the mechanical strength may decrease; if the D90 is less than 3 μm, the density, thermal conductivity, and mechanical strength may decrease; and if the D90 is more than 6.6 μm, the mechanical strength may decrease.

[0031] Furthermore, the second silicon-based powder may have a larger coefficient of variation (CV value) of particle distribution than the first silicon-based powder. The first silicon-based powder may have a particle distribution coefficient of variation (CV value) of 25 to 45%, preferably 26 to 44%. If the particle distribution coefficient of variation of the first silicon-based powder is less than 25%, the density, thermal conductivity, and mechanical strength may decrease, and if the particle distribution coefficient of variation is more than 45%, the density, thermal conductivity, and mechanical strength may decrease.

[0032] The second silicon-based powder may have a particle distribution coefficient of variation (CV value) of 56 to 77%, preferably 58 to 75%. If the particle distribution coefficient of variation of the second silicon-based powder is less than 56%, the density, thermal conductivity, and mechanical strength may decrease, and if the particle distribution coefficient of variation is more than 77%, the density, thermal conductivity, and mechanical strength may decrease.

[0033] Furthermore, the content of the first silicon-based powder may be greater than the content of the second silicon-based powder, and preferably the silicon-based powder may include the first silicon-based powder and the second silicon-based powder in a weight ratio of 1:0.4 to 0.7, more preferably the first silicon-based powder and the second silicon-based powder in a weight ratio of 1:0.43 to 0.65. If the weight ratio of the first silicon-based powder to the second silicon-based powder is less than 1:0.4, mechanical strength may be reduced. If the weight ratio of the first silicon-based powder to the second silicon-based powder is greater than 1:0.7 or the content of the first silicon-based powder is less than the content of the second silicon-based powder, denseness, thermal conductivity, and mechanical strength may be reduced.

[0034] The silicon-based powder may be contained in an amount of 80 to 94 wt %, preferably 82 to 92 wt %, based on the total weight of the mixed powder. If the silicon-based powder is contained in an amount of less than 80 wt % of the total weight of the mixed powder, the thermal conductivity may decrease, and if the silicon-based powder is contained in an amount of more than 94 wt %, the density, thermal conductivity, and mechanical strength may decrease.

[0035] Next, the nitride-based sintering aid will be described. The nitride-based sintering aid functions to improve density, thermal conductivity, and mechanical strength, and may be any nitride-based sintering aid commonly used in the art, and may preferably include at least one of MgSiN and YSiN.

[0036] In this case, the MgSiN2 may have an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm, and preferably an average particle size of 0.5 to 3 μm, a particle size distribution D10 of 0.1 to 0.5 μm, a particle size distribution D50 of 0.5 to 3 μm, and a particle size distribution D90 of 1.5 to 5 μm. If the average particle size of the MgSiN2 is less than 0.3 μm, it will be difficult to achieve uniform physical properties, and if the average particle size exceeds 0.4 μm, the density, thermal conductivity, and mechanical strength may decrease. Furthermore, if the particle size distribution D10 of the MgSiN2 is less than 0.08 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 0.55 μm, the density, thermal conductivity, and mechanical strength may decrease. If the particle size distribution D50 of the MgSiN2 is less than 0.3 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 4 μm, the density, thermal conductivity, and mechanical strength may decrease. If the particle size distribution D90 of the MgSiN2 is less than 1.5 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 6 μm, the density, thermal conductivity, and mechanical strength may decrease.

[0037] The Y2Si4N6C may have an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm, and preferably has an average particle size of 0.5 to 3 μm, a particle size distribution D10 of 0.1 to 0.5 μm, a particle size distribution D50 of 0.5 to 3 μm, and a particle size distribution D90 of 1.5 to 5 μm. If the average particle size of the Y2Si4N6C is less than 0.3 μm, it is difficult to achieve uniform physical properties, and if the average particle size exceeds 4 μm, the density, thermal conductivity, and mechanical strength may decrease. Furthermore, if the particle size distribution D10 of the Y2Si4N6C is less than 0.08 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 0.55 μm, the density, thermal conductivity, and mechanical strength may decrease. If the particle size distribution D50 of the Y2Si4N6C is less than 0.3 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 4 μm, the density, thermal conductivity, and mechanical strength may decrease. If the particle size distribution D90 of the Y2Si4N6C is less than 1.5 μm, it is difficult to exhibit uniform physical properties, and if it exceeds 6 μm, the density, thermal conductivity, and mechanical strength may decrease.

[0038] Meanwhile, the content of MgSiN2 may be the smallest in the total content of the nitride-based sintering aid, and preferably the nitride-based sintering aid may include the MgSiN2 and Y2Si4N6C in a weight ratio of 1:1.2 to 2.6, and more preferably the nitride-based sintering aid may include the first sintering aid and the second sintering aid in a weight ratio of 1:1.3 to 2.5. If the content of MgO in the total content of the nitride-based sintering aid is not the smallest, or if the weight ratio of MgSiN2 and Y2Si4N6C is less than 1:1.2, it may be difficult to achieve uniform physical properties, and if the weight ratio exceeds 1:2.6, the density, thermal conductivity, and mechanical strength may be reduced.

[0039] Furthermore, among the nitride-based sintering aids, MgSiN2 may have the largest coefficient of variation (CV value) of particle distribution. If MgSiN2 does not have the largest coefficient of variation of particle distribution among the nitride-based sintering aids, it may be difficult to achieve uniform physical properties, and the density, thermal conductivity, and mechanical strength may be reduced.

[0040] The MgSiN2 may have a particle distribution coefficient of variation (CV value) of 55 to 75%, preferably 56 to 74%, and the Y2Si4N6C may have a particle distribution coefficient of variation (CV value) of 35 to 55%, preferably 36 to 54%.

[0041] If the coefficient of variation of the particle distribution of the MgSiN2 is less than 55%, it is difficult to express uniform physical properties, and the density, thermal conductivity, and mechanical strength may decrease; if it exceeds 75%, it is difficult to express uniform physical properties, and the density, thermal conductivity, and mechanical strength may decrease; if the coefficient of variation of the particle distribution of the Y2Si4N6C is less than 35%, it is difficult to express uniform physical properties, and the density, thermal conductivity, and mechanical strength may decrease; and if it exceeds 55%, it is difficult to express uniform physical properties, and the density, thermal conductivity, and mechanical strength may decrease.

[0042] Meanwhile, the present invention provides a silicon nitride substrate obtained by nitriding and sintering the above-mentioned composition for producing a silicon nitride substrate. In this case, the order of nitriding and sintering the composition is not particularly limited, and nitriding may be performed first and then sintering, or sintering may be performed first and then nitriding, and is not particularly limited in the present invention.

[0043] In addition, the specific method and conditions for the nitriding and sintering are not particularly limited in the present invention, as publicly known methods can be used. The composition for producing a silicon nitride substrate of the present invention and the silicon nitride substrate produced therefrom exhibit excellent sintered body density and thermal conductivity, as well as excellent mechanical strength such as bending strength and abrasion resistance, while also exhibiting uniform physical properties.

[0044] Example The present invention will be described in more detail through the following examples, but the following examples should not be construed as limiting the scope of the present invention, but should be construed as being intended to aid in the understanding of the present invention.

[0045] Example 1 First, 87% by weight of silicon-based powder containing a first silicon-based powder having an average particle size of 5.4 μm, a particle size distribution D10 of 3 μm, a D50 of 5.3 μm, a D90 of 7.9 μm, and a particle distribution coefficient of variation (CV value) of 35% and a second silicon-based powder having an average particle size of 2.4 μm, a particle size distribution D10 of 0.68 μm, a D50 of 2.0 μm, a D90 of 4.8 μm, and a particle distribution coefficient of variation (CV value) of 66.6% in a weight ratio of 1:0.54, and a second silicon-based powder having an average particle size of 1.7 μm, a particle size distribution D10 of 0.23 μm, a D50 of 1.6 μm, a D90 of 4.3 μm, and a particle distribution coefficient of variation (CV value) of 66.6%. MgSiN2 with a coefficient of variation (CV) of 65% and Y2Si4N6C with an average particle size of 1.8μm, particle size distribution D10 of 0.38μm, D50 of 1.74μm, D90 of 3.1μm, and a coefficient of variation (CV) of 45% were mixed in a premixer with 13 wt% of a nitride-based sintering aid containing Y2Si4N6C in a weight ratio of 1:1.89. The mixture was then milled in a basket mill to produce a mixed powder slurry with an average particle size of 2.3μm, particle size distribution D10 of 0.36μm, D50 of 1.9μm, D90 of 5μm, and a coefficient of variation (CV) of 75.5%.

[0046] 100 parts by weight of the mixed powder was then mixed and dispersed in a primary mixer with 80 parts by weight of solvent and 1 part by weight of dispersant, followed by secondary mixing with 10 parts by weight of organic binder polyvinyl butyral (PVB) and 5 parts by weight of dioctyl phthalate (DOP) to prepare a casting slurry. The resulting slurry was then used to produce 250 μm-thick silicon green sheets using a doctor blade method. The green sheets were cut to account for sintering shrinkage, and both sides of the sheets were coated with BN (boron nitride) to prevent reaction between the sheets during sintering. Several BN-coated sheets were stacked and subjected to binder burnout (BBO), a process to remove the organic binder, at 900°C in a reducing gas atmosphere to prevent silicon decomposition. The sheet after BBO was placed in a BN box to control the reactivity with carbon in a reducing atmosphere. Using GPS (gas pressure sintering), the sheet was nitrided at 1400°C for 2 hours and sintered at 1900°C for 6 hours to produce a silicon nitride substrate.

[0047] <Examples 2 to 8 and Comparative Examples 1 and 2> The same procedure as in Example 1 was carried out to produce silicon nitride substrates as shown in Tables 1 and 2 below, with the average particle size of the mixed powder, the coefficient of variation of particle distribution, the ratio of particle size distributions D10 and D50, the particle size distributions D10, D50, and D90, the contents and average particle sizes of the first silicon-based powder and the second silicon-based powder, etc. being changed.

[0048] <Experimental Example 1> The silicon nitride substrates produced in Examples 1 to 8 and Comparative Examples 1 and 2 were evaluated for the following physical properties, and the results are shown in Tables 1 and 2.

[0049] 1. Density (compactness) evaluation The density of each of the silicon nitride substrates produced in Examples 1 to 8 and Comparative Examples 1 and 2 was measured using the Archimedes method.

[0050] 2.Thermal conductivity evaluation For each silicon nitride substrate manufactured in Examples 1 to 8 and Comparative Examples 1 and 2, a test piece with a thickness of approximately 500 μm and a size of 10 mm x 10 mm was prepared. The thermal conductivity was measured using the international standard ASTM E1461 (standard Test Method for Thermal Diffusivity by the laser Flash Method), and the thermal diffusivity was measured using a laser flash apparatus (NETZCH, Germany). The specific heat was also measured and calculated using the following equation 2.

[0051] [Formula 2] Thermal conductivity (k)=α·ρ·Cp In the above formula 2, α is the thermal diffusion coefficient (mm 2 / S), ρ is density (g / cm 3 ), and Cp indicates heat capacity (J / (kg·K)).

[0052] 3. Bending strength evaluation For each of the silicon nitride substrates manufactured in Examples 1 to 8 and Comparative Examples 1 and 2, the bending strength was measured in accordance with the international standard ISO 14704 (Fine ceramics (advanced ceramics, advanced technical ceramics) - test method for flexural strength of monolithic ceramics at 100 mm temperature). A universal testing machine was used to support the test specimen at two support points spaced 30 mm apart, and a load was applied to the midpoint between the two support points using a crosshead that moved at a speed of 1 mm per minute. The maximum load at which the test specimen broke was measured, and the bending strength was calculated using the following equation 3.

[0053] [Formula 3] Bending strength (σ) = 3 × P × L / 2 × w × t 2 In the above formula 3, P represents the maximum load, L represents the length of the test piece, w represents the width of the test piece, and t represents the thickness of the test piece.

[0054] [Table 1]

[0055] [Table 2]

[0056] As can be seen from Tables 1 and 2, Examples 1 to 3, which satisfy all of the requirements for the average particle size, particle distribution coefficient of variation, particle size distribution D10 to D50 ratio, particle size distribution D10, D50 and D90, and the respective contents and average particle sizes of the first silicon-based powder and the second silicon-based powder, of the mixed powder according to the present invention, can simultaneously achieve significantly superior effects in terms of density, thermal conductivity and mechanical strength compared to Examples 4 to 9 and Comparative Examples 1 and 2, which do not satisfy any of these requirements.

[0057] <Examples 9 to 16 and Comparative Example 3> The silicon nitride substrates shown in Tables 3 to 5 below were manufactured by carrying out the same procedure as in Example 1, and varying the weight ratio of the first silicon-based powder to the second silicon-based powder, the average particle size, the particle distribution variation coefficient, the particle size distribution D10, D50, and D90, and the average particle size, the particle distribution variation coefficient, and the ratio of the particle size distribution D10 to D50 of the mixed powder.

[0058] <Experimental Example 2> The density, thermal conductivity, and bending strength of each of the silicon nitride substrates according to Examples 1, 5 to 16, and Comparative Examples 2 and 3 were evaluated in the same manner as in Experimental Example 1, and the results are shown in Tables 3 to 5 below.

[0059] [Table 3] TIFF2026507339000004.tif86158

[0060] [Table 4] TIFF2026507339000006.tif83157

[0061] [Table 5] TIFF2026507339000008.tif84157

[0062] As can be seen from Tables 3 to 5, Example 1, which satisfies all of the requirements for the weight ratio, average particle size, particle distribution coefficient of variation, particle size distributions D10, D50, and D90 of the first silicon-based powder and the second silicon-based powder according to the present invention, as well as the average particle size, particle distribution coefficient of variation, and particle size distribution D10 to D50 ratio of the mixed powder, can simultaneously achieve significantly superior effects in density, thermal conductivity, and mechanical strength compared to Examples 5 to 16 and Comparative Examples 2 and 3, which do not satisfy any of these requirements.

[0063] Although one embodiment of the present invention has been described above, the concept of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the concept of the present invention can easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same concept, which would also fall within the scope of the concept of the present invention.

Claims

1. A mixed powder containing a silicon-based powder and a nitride-based sintering aid is included, The mixed powder has a particle distribution coefficient of variation (CV value) of 65 to 86%.

2. 2. The composition for producing a silicon nitride substrate according to claim 1, wherein the mixed powder has an average particle size of 0.5 to 4 μm.

3. 2. The composition for producing a silicon nitride substrate according to claim 1, wherein the mixed powder has a ratio of particle size distribution D10 (μm) to particle size distribution D50 (μm) of 1:1.8 to 18.

5.

4. 2. The composition for producing a silicon nitride substrate according to claim 1, wherein the mixed powder has a particle size distribution D10 of 0.15 to 0.55 μm, a particle size distribution D50 of 1 to 2.7 μm, and a particle size distribution D90 of 3.8 to 6.2 μm.

5. 2. The composition for producing a silicon nitride substrate according to claim 1, wherein the silicon-based powder comprises a first silicon-based powder and a second silicon-based powder having an average particle size smaller than that of the first silicon-based powder.

6. The composition for producing a silicon nitride substrate according to claim 5 , wherein the content of the first silicon-based powder is greater than the content of the second silicon-based powder.

7. 6. The composition for producing a silicon nitride substrate according to claim 5, wherein the second silicon-based powder has a larger particle distribution coefficient of variation (CV value) than the first silicon-based powder.

8. the first silicon-based powder has an average particle size of 4.1 to 6.6 μm; 6. The composition for producing a silicon nitride substrate according to claim 5, wherein the second silicon-based powder has an average particle size of 1.1 to 3.7 μm.

9. 6. The composition for producing a silicon nitride substrate according to claim 5, wherein the silicon-based powder comprises the first silicon-based powder and the second silicon-based powder in a weight ratio of 1:0.4 to 0.

7.

10. The first silicon-based powder has a particle size distribution D10 of 2.2 to 3.8 μm, a particle size distribution D50 of 4.1 to 6.5 μm, and a particle size distribution D90 of 6.7 to 9.1 μm; 6. The composition for producing a silicon nitride substrate according to claim 5, wherein the second silicon-based powder has a particle size distribution D10 of 0.4 to 0.95 μm, a particle size distribution D50 of 1.1 to 2.8 μm, and a particle size distribution D90 of 3 to 6.6 μm.

11. the first silicon-based powder has a particle distribution coefficient of variation (CV value) of 25 to 45%, 6. The composition for producing a silicon nitride substrate according to claim 5, wherein the second silicon-based powder has a particle distribution coefficient of variation (CV value) of 56 to 77%.

12. 2. The composition for producing a silicon nitride substrate according to claim 1, wherein the silicon-based powder is contained in an amount of 80 to 94 wt % of the total weight of the mixed powder.

13. The nitride-based sintering aid is MgSiN ２ and Y ２ Si ４ N ６ The composition for producing a silicon nitride substrate according to claim 1 , further comprising at least one of C.

14. The MgSiN ２ has an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm, The Y ２ Si ４ N ６ 14. The composition for producing a silicon nitride substrate according to claim 13, wherein C has an average particle size of 0.3 to 4 μm, a particle size distribution D10 of 0.08 to 0.55 μm, a particle size distribution D50 of 0.3 to 4 μm, and a particle size distribution D90 of 1.5 to 6 μm.

15. The total content of the nitride-based sintering aid is MgSiN ２ The content of is the lowest, Among the nitride-based sintering aids, MgSiN ２ 14. The composition for producing a silicon nitride substrate according to claim 13, wherein the particle distribution coefficient of variation (CV value) is the largest.

16. The MgSiN ２ has a particle distribution coefficient of variation (CV value) of 55 to 75%, The Y ２ Si ４ N ６ 14. The composition for producing a silicon nitride substrate according to claim 13, wherein C has a particle distribution coefficient of variation (CV value) of 35 to 55%.

17. The nitride-based sintering aid is MgSiN ２ and Y ２ Si ４ N ６ The composition for producing a silicon nitride substrate according to claim 13, comprising C in a weight ratio of 1:1.2 to 2.

6.

18. A silicon nitride substrate obtained by nitriding and sintering the composition for producing a silicon nitride substrate according to any one of claims 1 to 17.

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