Laminate structure for manufacturing silicon nitride substrate, method for manufacturing silicon nitride substrate having reduced warpage, and silicon nitride substrate manufactured thereby

Abstract

Provided is a laminate structure for manufacturing a silicon nitride substrate, comprising: an upper plate; a lower plate; and at least one silicon nitride laminate sheet interposed between the upper plate and the lower plate, wherein the silicon nitride laminate sheet comprises one or a plurality of laminated silicon nitride sheets, and spherical boron nitride is coated on at least one surface of the silicon nitride laminate sheet.

Description

A laminated structure for manufacturing a silicon nitride substrate, a method for manufacturing a silicon nitride substrate with suppressed warpage, and a silicon nitride substrate manufactured thereby

[0001] The present invention relates to a laminated structure for manufacturing a silicon nitride substrate, a method for manufacturing a silicon nitride substrate with suppressed warpage, and a silicon nitride substrate manufactured thereby.

[0002] Ceramic materials with high electrical insulation and thermal conductivity can be used as heat transfer media, rapidly transferring heat generated by components. Ceramic materials are used as substrates for transport devices, substrates for highly integrated electronic circuits, heat dissipation components in laser oscillation units, reaction vessel components in semiconductor manufacturing equipment, and precision machine components.

[0003] In particular, ceramic substrates used in high-power power devices require high insulation, high voltage resistance, high thermal conductivity, high strength, and low dielectric constant. Ceramic substrates that meet these requirements include aluminum nitride substrates, alumina substrates, and silicon nitride substrates.

[0004] Silicon nitride (Si3N4) substrates have high strength (500 to 800 MPa), high toughness (5 to 8 MPa m), and excellent thermal expansion coefficient compatibility with silicon (Si). Furthermore, silicon nitride (Si3N4) substrates have high thermal conductivity (70 to 170 W / mK). In other words, silicon nitride (Si3N4) substrates are suitable as materials for next-generation high-power power devices.

[0005] The purpose of the present invention is to provide a method for manufacturing a silicon nitride substrate with suppressed warpage, which can manufacture a silicon nitride substrate with a low variation in the content ratio of each component depending on the location, suppressed warpage, and reduced variation in thermal and mechanical properties.

[0006] An object of the present invention is to provide a laminated structure for manufacturing a silicon nitride substrate formed during a method for manufacturing the above-described warpage-suppressed silicon nitride substrate.

[0007] The purpose of the present invention is to provide a silicon nitride substrate manufactured by a method for manufacturing the above-described warpage-suppressed silicon nitride substrate, which has a low variation in the content ratio of each component, suppresses warpage, and reduces variation in thermal and mechanical properties.

[0008] The objectives of the present invention are not limited to those mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0009] In one embodiment of the present invention, there is provided an upper plate; a lower plate; and at least one silicon nitride laminated sheet interposed between the upper plate and the lower plate; wherein the silicon nitride laminated sheet comprises one or a plurality of laminated silicon nitride sheets;

[0010] Provided is a laminated structure for manufacturing a silicon nitride substrate, in which spherical particle-shaped boron nitride is applied on at least one surface of the above silicon nitride laminated sheet.

[0011] The cumulative volume particle size D50 of the particle diameter of the above-mentioned spherical particle-shaped boron nitride may be 10㎛ to 500㎛.

[0012] The above silicon nitride sheet may include yttrium oxide (Y2O3), magnesium oxide (MgO), or both.

[0013] A silicon nitride substrate can be manufactured by degreasing and sintering the laminated structure for manufacturing the above silicon nitride substrate.

[0014] The above-mentioned manufactured silicon nitride substrate includes magnesium (Mg), yttrium (Y), and silicon (Si), and the difference in the magnesium content measured at any two points relative to the total content of 100 mass% of magnesium (Mg), yttrium (Y), and silicon (Si) in the silicon nitride substrate may be within 7 mass%.

[0015]

[0016] In one embodiment of the present invention,

[0017] A step of forming a slurry by mixing silicon nitride powder, ceramic additives and a solvent;

[0018] A step of forming the above slurry to form a silicon nitride sheet;

[0019] A step of forming a silicon nitride laminated sheet from the above silicon nitride sheet;

[0020] A step of applying spherical particle-shaped boron nitride on at least one surface of the above silicon nitride laminated sheet;

[0021] A step of forming a laminated structure by interposing at least one silicon nitride laminated sheet between an upper plate and a lower plate;

[0022] A step of performing a degreasing process on the above laminated structure; and

[0023] A step of performing a sintering process on the above laminated structure;

[0024] A method for manufacturing a silicon nitride substrate with suppressed warpage is provided.

[0025] After the above degreasing process and the sintering process, the silicon nitride substrate can be formed from the silicon nitride laminated sheet.

[0026] The above ceramic additive may include yttrium oxide (Y2O3), magnesium oxide (MgO), or both.

[0027] The cumulative volume particle size D50 of the particle diameter of the boron nitride in the above spherical particle form may be 10 ㎛ to 500 ㎛.

[0028] The spherical particle-shaped boron nitride can be applied wet or dry on at least one surface of the silicon nitride laminated sheet.

[0029] A boron nitride slurry can be prepared by mixing the spherical particle-shaped boron nitride and a wet solvent on at least one surface of the silicon nitride laminated sheet, and applied by spraying.

[0030] The above boron nitride slurry can be applied to one or both sides of the silicon nitride laminated sheet using nitrogen pressure, and then the wet solvent can be removed by hot air drying.

[0031] The spherical particle-shaped boron nitride powder can be applied on at least one surface of the silicon nitride laminated sheet.

[0032]

[0033] In one embodiment of the present invention, a silicon nitride substrate is provided, wherein the difference in the magnesium content measured at any two points relative to the total content of 100 mass% of magnesium (Mg), yttrium (Y), and silicon (Si) among the silicon nitride substrates including magnesium (Mg), yttrium (Y), and silicon (Si) is within 7 mass%.

[0034]

[0035] In one embodiment of the present invention, a silicon nitride substrate is manufactured according to a method for manufacturing a silicon nitride substrate with suppressed warpage, wherein a diagonal length (L, mm) of the square silicon nitride substrate is scanned with a non-contact three-dimensional measuring device, and a difference (ΔZ, mm) between the lowest point and the highest point of one side of the silicon nitride substrate in the height direction from the sample holder is measured, and a ratio of the measured diagonal length (L) and ΔZ, ΔZ / L (mm / mm), is calculated to be 0.0015 or less.

[0036] The method for manufacturing the above-described warpage-suppressed silicon nitride substrate according to the present invention can manufacture a silicon nitride substrate in which the deviation in the content ratio of each component depending on the location is low, warpage is suppressed, and the deviation in thermal and mechanical properties is reduced.

[0037] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0038] FIG. 1 is a flowchart illustrating a method for manufacturing a silicon nitride substrate with suppressed warpage according to one embodiment of the present invention.

[0039] Figures 2 to 4 are schematic diagrams for explaining step (S10) in Figure 1.

[0040] Figure 5 is a schematic diagram for explaining step (S20) in Figure 1.

[0041] Figure 6 is a schematic diagram for explaining step (S30) in Figure 1.

[0042] Figure 7 is a schematic diagram for explaining step (S40) in Figure 1.

[0043] Figure 8 is a schematic diagram for explaining step (S50) in Figure 1.

[0044] Figure 9 is a schematic diagram for explaining step (S60) in Figure 1.

[0045] Figure 10 is a schematic diagram for explaining step (S70) in Figure 1.

[0046] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0047] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0048] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0049]

[0050] In one embodiment of the present invention, a step of forming a slurry by mixing silicon nitride powder, a ceramic additive, and a solvent;

[0051] A step of forming the above slurry to form a silicon nitride sheet;

[0052] A step of forming a silicon nitride laminated sheet from the above silicon nitride sheet;

[0053] A step of applying spherical particle-shaped boron nitride on at least one surface of the above silicon nitride laminated sheet;

[0054] A step of forming a laminated structure by interposing at least one silicon nitride laminated sheet coated with boron nitride between an upper plate and a lower plate;

[0055] A step of performing a degreasing process on the above laminated structure; and

[0056] A step of performing a sintering process on the above laminated structure;

[0057] A method for manufacturing a silicon nitride substrate with suppressed warpage is provided.

[0058] The silicon nitride substrate manufactured by the method for manufacturing the above-mentioned warpage-suppressed silicon nitride substrate is a sintered substrate manufactured by a sintering process. Typically, warpage in the silicon nitride substrate is due to a difference in composition between the edge portion and the center portion within the laminated sheet as the sintering process progresses. Additives used to facilitate liquid-phase sintering of silicon nitride include yttrium oxide, magnesium oxide, etc. These additive components sublimate during sintering, resulting in changes in content. However, since these additive components have different diffusion rates within the silicon nitride laminated sheet, a difference in the additive ratio between the edge portion and the center portion occurs, which causes warpage of the silicon nitride substrate.

[0059] Warping in substrates increases the bonding defect rate during subsequent post-processing steps involving metal layer bonding, thereby reducing yield. Therefore, suppressing warpage in silicon nitride substrates is crucial for improving yield.

[0060] A silicon nitride substrate manufactured by the method for manufacturing a silicon nitride substrate with suppressed warpage can suppress warpage by reducing such deviation.

[0061] Hereinafter, each step of the method for manufacturing the above-mentioned warpage-suppressed silicon nitride substrate will be described in more detail.

[0062] FIG. 1 is a flowchart illustrating a method for manufacturing a silicon nitride substrate with suppressed warpage according to one embodiment of the present invention. Referring to FIG. 1, a method for manufacturing a silicon nitride substrate with suppressed warpage according to one embodiment of the present invention may include a step of mixing silicon nitride powder, a ceramic additive, and a solvent to form a slurry (S10), a step of molding the slurry to form a silicon nitride sheet (S20), a step of forming a silicon nitride laminated sheet from the silicon nitride sheet (S30), a step of applying spherical particle-shaped boron nitride on at least one surface of the silicon nitride laminated sheet (S40), a step of forming a laminated structure having at least one silicon nitride laminated sheet interposed between an upper plate and a lower plate (S50), a step of performing a degreasing process on the laminated structure (S60), and a step of performing a sintering process on the laminated structure (S70).

[0063] The ceramic additive (SA) may include yttrium oxide (Y2O3), magnesium oxide (MgO), or both. The ceramic additive (SA) may be added to the slurry in powder form.

[0064] In one embodiment, the ceramic additive (SA) may include magnesium oxide (MgO).

[0065] In one embodiment, the ceramic additive (SA) may further comprise an additional oxide (e.g., zirconium oxide).

[0066] The mass ratio of yttrium oxide (Y2O3) to the ceramic additive (SA) may be 0.3 to 0.5. The mass ratio of the magnesium oxide (MgO) to the ceramic additive (SA) may be 0.5 to 0.7.

[0067] FIG. 2 is a schematic diagram for explaining the step (S10) of forming a slurry by mixing silicon nitride powder, ceramic additive, and solvent in FIG. 1.

[0068] Referring to FIGS. 1 and 2, a solvent (SV) and a plurality of balls (BA) may be provided within a container (CON). The solvent (SV) may be an organic solvent, for example, may include isopropyl alcohol and toluene. The isopropyl alcohol and toluene may be mixed in a volume ratio of 4:6. The balls (BA) may include silicon nitride.

[0069] A first mixture (MI1) can be prepared by adding silicon nitride (Si3N4) powder (SNP), a ceramic additive (SA), and, optionally, a dispersant (DIS) to a solvent (SV) in a container (CON). A commercially available dispersant (DIS) can be used as the dispersant (DIS), for example, BYK-111, a type of ester block copolymer manufactured by BYK Chemie of Germany, can be used.

[0070] The solvent (SV) may have 40 Vol% to 60 Vol% with respect to the total volume of the first mixture (MI1). The silicon nitride powder (SNP) may have 15 Vol% to 25 Vol% with respect to the total volume of the first mixture (MI1). The ceramic additive (SA) may have 5 wt% to 10 wt% with respect to the mass of the first mixture (MI1). More specifically, the ceramic additive (SA) may have 5 wt% to 7 wt% with respect to the mass of the first mixture (MI1). The first mixture (MI1) includes the ceramic additive (SA) in the above content range, so that the silicon nitride substrate can have properties (e.g., thermal conductivity) at a predetermined level, and also, the purity of the silicon nitride substrate can be at a predetermined level.

[0071] For the first mixture (MI1), the first mixture (MI1) can be uniformly mixed, for example, using a ball milling process or basket milling. Silicon nitride balls can be used in the ball milling process or basket milling. The balls can physically assist in uniformly mixing the first mixture (MI1).

[0072] Specifically, the ball milling process may include rotating a container containing the first mixture (MI1) at a constant speed using a ball milling machine. As the container rotates, mechanical grinding and uniform mixing may be performed by balls within the container. The rotation speed of the ball milling machine may be between 100 rpm and 500 rpm.

[0073] Referring to FIGS. 1 and 3, after the ball milling process, a second mixture (MI2) may be prepared by adding a binder (BI) and a plasticizer (PL) to a first mixture (MI1). The binder (BI) may include at least one of a cellulose derivative such as ethyl cellulose, methyl cellulose, nitrocellulose, and carboxycellulose; a resin such as polyvinyl alcohol, an acrylic acid ester, a methacrylic acid ester, and polyvinyl butyral; and a mixture of the derivatives and the resins. For example, the binder (BI) may include polyvinyl butyral (PVB). The plasticizer (PL) may include dibutyl phthalate or dioctyl phthalate. The mass of the plasticizer (PL) added may be about 50% of the mass of the binder (BI) added. Additionally, more solvent may be added to the first mixture (MI1).

[0074] For the second mixture (MI2), the second mixture (MI2) can be uniformly mixed, for example, by a method such as ball milling or basket milling. By uniformly mixing the second mixture (MI2) through the ball milling process, a slurry (SL) can be formed (S120). The ball milling process can be substantially the same as or similar to the ball milling process described above. The balls can then be removed.

[0075] Referring to FIGS. 1 and 4, volatile gases can be removed from a slurry (SL) formed by a ball milling process by aging the slurry (SL). During the aging of the slurry (SL), the slurry (SL) can be stirred using a stirrer (SIT). The aging can be performed for approximately 24 hours.

[0076] FIG. 5 is a schematic diagram for explaining the step (S20) of forming a silicon nitride sheet by molding the slurry in FIG. 1.

[0077] Referring to FIGS. 1 and 5, the slurry (SL) prepared in step (S10) can be formed into a silicon nitride sheet (SH) by a tape casting process (S130). Specifically, the tape casting process can be performed by pouring the slurry (SL) onto a blade set to a constant dam height, and applying the slurry (SL) onto a moving substrate film. The solvent can be evaporated from the slurry (SL) applied onto the substrate film and removed, thereby obtaining a silicon nitride sheet (SH) molded body. The substrate film can be a stainless steel tape, an oil-based paper tape, or a polymer tape such as polyester. For example, the slurry (SL) can be poured onto a doctor blade set to a dam height of about 0.3 mm, and the slurry (SL) can be applied onto a substrate film moving at a predetermined speed (e.g., 0.1 m / min to 1 m / min). Afterwards, a drying process and a process of removing the substrate film are performed to obtain a silicon nitride sheet (SH).

[0078] The tape casting process can be performed at a temperature of 30°C to 80°C. The silicon nitride sheet (SH) formed by the tape casting process can be cut to an appropriate size. The thickness of the silicon nitride sheet (SH) can be 0.1 mm to 0.5 mm.

[0079] The silicon nitride sheet (SH) may have a size of M × N. Each of M and N may be from 60 mm to 300 mm, but is not particularly limited. That is, each of M and N may be changed depending on the size of the desired silicon nitride substrate.

[0080] FIG. 6 is a schematic diagram illustrating a step (S30) of forming a silicon nitride laminated sheet from the silicon nitride sheet in FIG. 1. A silicon nitride laminated sheet may also be formed by laminating multiple silicon nitride sheets. Although the silicon nitride laminated sheet may also be formed from a single silicon nitride sheet, for convenience, it is collectively referred to as a "laminated" sheet. Hereinafter, a process of forming a silicon nitride laminated sheet by laminating multiple silicon nitride sheets will be described by way of example.

[0081] Referring to FIGS. 1 and 6, a plurality of silicon nitride sheets (SH) prepared in step (S20) can be laminated. A lamination process can be performed on the laminated silicon nitride sheets (SH) to form a silicon nitride laminated sheet (SSH) (S30). For example, one to three silicon nitride sheets (SH) can be laminated to form a silicon nitride laminated sheet (SSH). The lamination process can be performed at a pressure of about 10 MPa and a temperature of about 60°C.

[0082] A silicon nitride laminated sheet (SSH) can be pressurized. The pressurization process can utilize a warm isostatic press (WIP). The pressurization process can be performed at a pressure of about 30 MPa and a temperature of about 70°C. Finally, the thickness (TH) of the silicon nitride laminated sheet (SSH) can be 0.3 mm to 4 mm.

[0083] The silicon nitride laminated sheet (SSH) may be formed by overlapping sheets (SH), and the size of the silicon nitride laminated sheet (SSH) may also be substantially the same as the size of the sheets (SH). In other words, the silicon nitride laminated sheet (SSH) may have a size of M × N. Each of M and N may be from 60 mm to 300 mm.

[0084] FIG. 7 is a schematic diagram for explaining a step (S40) of applying spherical particle-shaped boron nitride on at least one surface of the silicon nitride laminated sheet in FIG. 1.

[0085] FIG. 7 illustrates a silicon nitride laminated sheet (SSH) obtained in step (S30) in which spherical particle-shaped boron nitride is applied to one or both sides of the silicon nitride laminated sheet (SSH), where BNP represents the applied spherical particle-shaped boron nitride.

[0086] Sintering is performed in a crucible with multiple silicon nitride laminated sheets (SSH) overlapped (see S70), and in order to recover each silicon nitride substrate manufactured from each silicon nitride laminated sheet (SSH) after sintering, boron nitride powder can be applied dry or wet as a release agent to one or both sides of the silicon nitride laminated sheets (SSH) before performing a degreasing process.

[0087] In one embodiment, a boron nitride slurry is prepared by mixing the spherical particle-shaped boron nitride and a wet solvent, and can be applied by spraying. The wet solvent of the boron nitride slurry can be acetone or water. Specifically, the boron nitride slurry can be prepared by dispersing 10 to 20 mass% of boron nitride in acetone. The boron nitride slurry can be dispersed and used using a ball mill, a bead mill, a basket mill, or the like. The boron nitride slurry can be applied to one or both sides of a silicon nitride laminated sheet (SSH) using nitrogen pressure.

[0088] After application, the wet solvent of the boron nitride slurry is removed. For this purpose, hot air drying at 70 to 90°C can be performed.

[0089] In one embodiment, the spherical boron nitride particles may be applied dry in a powder state.

[0090] As the spherical boron nitride particles are positioned between the silicon nitride laminated sheets (SSH), microscopic spaces are created between the silicon nitride laminated sheets (SSH). As the sublimation rate of the ceramic additive in the center of the silicon nitride laminated sheets (SSH) becomes similar to that in the edge, the difference in composition ratio within the silicon nitride laminated sheets (SSH) due to sintering is reduced. As a result, since the ratio of the ceramic additive within the silicon nitride substrate obtained by sintering becomes relatively uniform, the deviation in physical properties according to position within the substrate is reduced, and warpage of the silicon nitride substrate can be suppressed.

[0091] In one embodiment, the cumulative volume particle size D50 of the particle diameter of the spherical boron nitride particles may be 10 µm to 500 µm, specifically, 10 µm to 300 µm, and more specifically, 10 µm to 35 µm. The spherical boron nitride particles may be used with the aforementioned particle size to uniformly adjust the ratio of the ceramic additive within the silicon nitride laminated sheet (SSH) upon sintering, thereby assisting in the manufacture of a silicon nitride substrate with suppressed warpage.

[0092] The above “cumulative volume particle size D50 of particle diameter” can be defined as a particle diameter corresponding to 50% of the volume accumulation amount, and can be measured using, for example, a laser diffraction method.

[0093] The above "spherical particle" is a particle having an aspect ratio of the shortest axis length to the longest axis length greater than 0.5. The lengths of the shortest axis and the longest axis refer to the lengths connecting two points where an axis, which is a straight line passing through the center point of the particle, intersects the surface of the particle. The center point of the particle may be the geometric center of the volume. In the case of a perfect sphere, the aspect ratio may be 1, but irregular shapes that naturally occur in the production of particles are not meaningfully considered in the context of the present invention, and a spherical particle is defined by the aspect ratio.

[0094] In one embodiment, the aspect ratio of the boron nitride in the spherical particle form may be 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more.

[0095] FIG. 8 is a schematic diagram for explaining a step (S50) of forming a laminated structure by interposing at least one silicon nitride laminated sheet coated with boron nitride between the upper plate and the lower plate of FIG. 1.

[0096] Referring to FIGS. 1 and 8, a laminated structure (SS) can be prepared. The laminated structure (SS) can include a lower plate (PLT1), an upper plate (PLT2), and a silicon nitride laminated sheet (SSH) coated with boron nitride interposed therebetween. Preparing the silicon nitride laminated structure (SS) can include interposing the silicon nitride laminated sheet (SSH) prepared in step (S40) between the lower plate (PLT1) and the upper plate (PLT2) (S150). If the boron nitride is wet-coated, the wet solvent of the boron nitride slurry is sufficiently removed by hot air drying, and then a plurality of the silicon nitride laminated sheets (SSH) are overlapped and positioned between the lower plate (PLT1) and the upper plate (PLT2).

[0097] The upper plate (PLT1) and the lower plate (PLT2) may include boron nitride. For example, the upper plate (PLT1) and the lower plate (PLT2) may be boron nitride plates.

[0098] Although FIG. 8 illustrates one silicon nitride laminate sheet (SSH) interposed between the lower plate (PLT1) and the upper plate (PLT2), the present invention is not limited thereto. In one embodiment, two or more laminate sheets (SSH) may be interposed between the lower plate (PLT1) and the upper plate (PLT2).

[0099] FIG. 9 is a schematic diagram for explaining a step (S60) of performing a degreasing process on the laminated structure of FIG. 1.

[0100] Referring to FIGS. 1 and 9, a debinding process (Binder Burn Out, BBO) may be performed (S60) on the laminated structure (SS) prepared in step (S50). As a result, organic substances such as binders, dispersants, and plasticizers within the silicon nitride laminated sheet (SSH) may be incinerated and removed. In one embodiment, the debinding process may be performed at a predetermined temperature under atmospheric pressure for about 30 to 100 hours. For example, the debinding process may be performed at a temperature of about 600°C for about 30 hours in an atmospheric furnace (AF). That is, the debinding process may be performed under the atmosphere (air).

[0101] FIG. 10 is a schematic diagram for explaining a step (S70) of performing a sintering process on the laminated structure of FIG. 1.

[0102] Referring to FIGS. 1 and 10, after step S60, a layered structure (SS) may be provided within a crucible (CRU). By placing a bedding powder (NP) within the crucible (CRU), the layered structure (SS) may be embedded within the bedding powder (NP). The bedding powder (NP) may include boron nitride powder, silicon nitride powder, or a mixture thereof. When the bedding powder (NP) includes a mixture of boron nitride powder and silicon nitride powder, the boron nitride powder and the silicon nitride powder may be mixed in a 1:1 ratio. In one embodiment, as shown in FIG. 10, the crucibles (CRU) may be stacked in a multi-stage structure, and a separate layered structure (SS) may be provided for each layer within each crucible (CRU).

[0103] By heating the crucible (CRU), a sintering process can be performed on the laminated structure (SS) (S70). As a result, the silicon nitride laminated sheet (SSH) can be sintered, thereby forming a silicon nitride substrate.

[0104] In one embodiment, the sintering process may be performed at a temperature of 1700°C to 2000°C for 6 to 12 hours. For example, the sintering process may be performed at a temperature of about 1900°C for about 6 hours. The sintering process may be performed in a nitrogen atmosphere. A sintered silicon nitride laminated sheet (SSH) may be obtained as a silicon nitride substrate.

[0105] The silicon nitride substrate may have a size of MXN, where M and N may each be from 40 mm to 200 mm. In one embodiment of the present invention, the size of the silicon nitride substrate may be reduced compared to the size of the silicon nitride laminated sheet (SSH) by a sintering process.

[0106]

[0107] In one embodiment of the present invention,

[0108] top plate;

[0109] lower plate; and

[0110] At least one silicon nitride laminated sheet interposed between the upper plate and the lower plate;

[0111] The above silicon nitride laminated sheet comprises one or a plurality of laminated silicon nitride sheets,

[0112] Boron nitride in the form of spherical particles is applied on at least one surface of the above silicon nitride laminated sheet.

[0113] A laminated structure for manufacturing a silicon nitride substrate is provided.

[0114] The above-described laminated structure for manufacturing a silicon nitride substrate may be a laminated structure for manufacturing a silicon nitride substrate manufactured in step (S50) of the method for manufacturing a silicon nitride substrate with suppressed warpage described above.

[0115] Accordingly, a detailed description of the laminated structure for manufacturing the above silicon nitride substrate is as described in the method for manufacturing the above silicon nitride substrate with suppressed warpage.

[0116] The cumulative volume particle size D50 of the particle diameter of the boron nitride in the above spherical particle form may be 10 ㎛ to 500 ㎛.

[0117] In the method for manufacturing a silicon nitride substrate with suppressed warpage described above, since the ceramic additive (SA) may include magnesium oxide (MgO), the silicon nitride sheet may include magnesium oxide (MgO). As described above, in addition to magnesium oxide (MgO), the silicon nitride sheet may further include a component included in the ceramic additive (SA).

[0118] A silicon nitride substrate can be manufactured by degreasing and sintering the laminated structure for manufacturing the above silicon nitride substrate.

[0119] The above-described laminated structure for manufacturing a silicon nitride substrate is manufactured according to the method for manufacturing a silicon nitride substrate with suppressed warpage, and thus, a silicon nitride substrate manufactured by degreasing and sintering the above-described laminated structure for manufacturing a silicon nitride substrate has a low variation in the content ratio of each component depending on the position, for example, a low variation in the content ratio of a magnesium component, and warpage is suppressed, and accordingly, the variation in thermal properties and mechanical properties is reduced.

[0120] In one embodiment, the difference in the magnesium content measured at any two points of the manufactured silicon nitride substrate may be within 7%, specifically, within 5%, and more specifically, within 3%.

[0121] In one embodiment of the present invention, a silicon nitride substrate is provided, wherein the difference in the magnesium content measured at any two points relative to the total content of 100 mass% of magnesium (Mg), yttrium (Y), and silicon (Si) among the silicon nitride substrates including magnesium (Mg), yttrium (Y), and silicon (Si) is within 7 mass%. The silicon nitride substrate can be manufactured by the method for manufacturing a silicon nitride substrate with suppressed warpage described above.

[0122] In one embodiment of the present invention, a silicon nitride substrate is manufactured according to a method for manufacturing a silicon nitride substrate with suppressed warpage, wherein a diagonal length (L, mm) of the square silicon nitride substrate is scanned with a non-contact three-dimensional measuring device, and a difference (ΔZ, mm) between the lowest point and the highest point of one side of the silicon nitride substrate in the height direction from the sample holder is measured, and a ratio of the measured diagonal length (L) and ΔZ, ΔZ / L (mm / mm), is calculated and has a value of 0.0015 or less, so as to provide a silicon nitride substrate. The silicon nitride substrate can be manufactured by the method for manufacturing a silicon nitride substrate with suppressed warpage described above.

[0123]

[0124] Hereinafter, examples and comparative examples of the present invention will be described. The following examples are merely exemplary of the present invention, and the present invention is not limited to the examples described below.

[0125]

[0126] (Example)

[0127] Example 1

[0128] A silicon nitride substrate was manufactured using the manufacturing method described in FIGS. 1 to 10. The cumulative volume particle size D50 of the spherical boron nitride particles used was 15 μm, and a boron nitride slurry was manufactured by mixing boron nitride powder with a wet solvent, which was then sprayed onto both sides of a silicon nitride laminated sheet (SSH). After coating, hot air drying was performed at 80°C to remove the wet solvent from the boron nitride slurry.

[0129]

[0130] Example 2

[0131] A silicon nitride substrate was manufactured in the same manner as in Example 1, except that the cumulative volume particle size D50 of the spherical particle-shaped boron nitride used was 30 μm.

[0132]

[0133] Comparative Example 1

[0134] A silicon nitride substrate was manufactured in the same manner as in Example 1, except that instead of the spherical particle-shaped boron nitride used in Example 1, plate-shaped particle-shaped boron nitride (with a cumulative volume particle size D50 of 7 μm) was used.

[0135]

[0136] (Experimental example)

[0137] bending measurement

[0138] Warpage was measured using a non-contact method. A square silicon nitride substrate (140 mm × 190 mm × 0.32 mm) was scanned in the diagonal direction of the silicon nitride substrate using a non-contact 3D measuring device. The ratio of the scanned diagonal length (L, mm) and the difference between the lowest and highest points (△Z, mm) on one side of the silicon nitride substrate in the height direction from the sample support, △Z / L (mm / mm), was defined as the warpage value.

[0139]

[0140] Measurement of magnesium content

[0141] Magnesium content was measured using XRF (Rigaku AZX400). A 140x190mm sample was loaded into the device to map the entire substrate. The mapping elements were selected as magnesium (mg), yttrium (y), and silicon (Si), and the measurement was performed semi-quantitatively to ensure that all three elements were 100%.

[0142] The measurement range for a single measurement was set to Φ10 mm, and the entire substrate was mapped sequentially to measure the element content (mass%) for each region. In this measurement, the number of measurement points was set to 109 and the measurement was performed.

[0143] The measured values ​​were calculated as ratios for each section based on the center of the silicon nitride substrate.

[0144]

[0145] The evaluation results of Examples 1-2 and Comparative Example 1 are shown in Table 1.

[0146] Deflection (mm / mm) Magnesium content ratio Magnesium content (wt%) @ CenterMinimum magnesium ratio by sectionMaximum magnesium ratio by sectionExample 10.0010±3%1.440.971.02Example 20.0015±5%1.460.951.03Comparative example 10.0023±9%1.510.911.07

[0147] Comparative Example 1 showed greater warpage and a greater deviation in magnesium content compared to Examples 1-2. Since the microscopic spaces that can be created by spherical boron nitride particles are reduced when plate-shaped boron nitride particles are used, the effect of similarly increasing the sublimation rate of ceramic additives in silicon nitride laminated sheets (SSH) is also reduced. Accordingly, it can be confirmed that Comparative Example 1 has inferior effects compared to Examples 1-2.

[0148] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the exemplary embodiments disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical spirit of the invention. Furthermore, even if the operational effects of the configurations of the invention have not been explicitly described and explained while describing the exemplary embodiments of the invention, it is also to be understood that the effects predictable by the configurations should be acknowledged.

Claims

1. Upper plate; lower plate; and At least one silicon nitride laminated sheet interposed between the upper plate and the lower plate; The above silicon nitride laminated sheet comprises one or a plurality of laminated silicon nitride sheets, Boron nitride in the form of spherical particles is applied on at least one surface of the above silicon nitride laminated sheet. A laminated structure for manufacturing silicon nitride substrates.

2. In paragraph 1, The cumulative volume particle size D50 of the boron nitride particle diameter of the above spherical particles is 10㎛ to 500㎛. A laminated structure for manufacturing silicon nitride substrates.

3. In paragraph 1, The above silicon nitride sheet comprises yttrium oxide (Y2O3), magnesium oxide (MgO) or both. A laminated structure for manufacturing silicon nitride substrates.

4. In paragraph 3, The above-mentioned silicon nitride substrate manufacturing laminated structure is degreased and sintered to manufacture a silicon nitride substrate. A laminated structure for manufacturing silicon nitride substrates.

5. In paragraph 4, The above-mentioned manufactured silicon nitride substrate contains magnesium (Mg), yttrium (Y) and silicon (Si), and the difference in the magnesium content measured at any two points relative to the total content of 100 mass% of magnesium (Mg), yttrium (Y) and silicon (Si) in the silicon nitride substrate is within 7 mass%. A laminated structure for manufacturing silicon nitride substrates.

6. A step of forming a slurry by mixing silicon nitride powder, ceramic additives and a solvent; A step of forming the above slurry to form a silicon nitride sheet; A step of forming a silicon nitride laminated sheet from the above silicon nitride sheet; A step of applying spherical particle-shaped boron nitride on at least one surface of the above silicon nitride laminated sheet; A step of forming a laminated structure by interposing at least one silicon nitride laminated sheet between an upper plate and a lower plate; A step of performing a degreasing process on the above laminated structure; and A step of performing a sintering process on the above laminated structure; A method for manufacturing a silicon nitride substrate with suppressed warpage.

7. In paragraph 6, After the above degreasing process and the sintering process, the silicon nitride substrate is formed from the silicon nitride laminated sheet. A method for manufacturing a silicon nitride substrate with suppressed warpage.

8. In paragraph 6, The above ceramic additive comprises yttrium oxide (Y2O3), magnesium oxide (MgO) or both. A method for manufacturing a silicon nitride substrate with suppressed warpage.

9. In paragraph 6, The cumulative volume particle size D50 of the boron nitride particle diameter of the above spherical particles is 10㎛ to 500㎛. A method for manufacturing a silicon nitride substrate with suppressed warpage.

10. In paragraph 6, The spherical particle-shaped boron nitride is wetly or dryly applied on at least one surface of the silicon nitride laminated sheet. A method for manufacturing a silicon nitride substrate with suppressed warpage.

11. In paragraph 6, A boron nitride slurry is prepared by mixing the spherical particle-shaped boron nitride and a wet solvent on at least one surface of the silicon nitride laminated sheet, and is applied by spraying. A method for manufacturing a silicon nitride substrate with suppressed warpage.

12. In paragraph 11, The above boron nitride slurry is applied to one or both sides of the silicon nitride laminated sheet using nitrogen pressure, and then the wet solvent is removed by hot air drying. A method for manufacturing a silicon nitride substrate with suppressed warpage.

13. In paragraph 6, Applying the spherical particle-shaped boron nitride powder on at least one surface of the silicon nitride laminated sheet A method for manufacturing a silicon nitride substrate with suppressed warpage.

14. A silicon nitride substrate containing magnesium (Mg), yttrium (Y), and silicon (Si), wherein the difference in the magnesium content measured at any two points relative to the total content of 100 mass% of magnesium (Mg), yttrium (Y), and silicon (Si) is within 7 mass%.

15. A silicon nitride substrate manufactured according to a method for manufacturing a silicon nitride substrate with suppressed warpage according to Article 6, wherein the diagonal length (L, mm) of the square silicon nitride substrate is scanned with a non-contact three-dimensional measuring device, and the difference (ΔZ, mm) between the lowest point and the highest point of one side of the silicon nitride substrate in the height direction from the sample support is measured, and the ratio of the measured diagonal length (L) and ΔZ, ΔZ / L (mm / mm), is calculated to be 0.0015 or less.

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