JP2000072552A - Silicon nitride heat radiation member and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a silicon nitride heat radiation member having excellent sheet moldability, capable of excellently producing a member having a thin thickness such as a multilayered wiring board, etc., having a high heat conductivity. SOLUTION: Mixed powder comprising silicon nitride powder having 0.4-0.7 μm average particle diameter and 60-80% accumulation of particles having <=1 μm particle diameter and 90% accumulation with 2-5 μm particle size distribution and a sintering auxiliary is mixed with an organic solvent and a binder to prepare a slurry, which is used and formed by a sheet forming method into a sheetlike state so as to make the thickness after sintering 0.03-1.0 mm. The formed sheets are properly laminated, baked in a nonoxidizing atmosphere at <=1,800 deg.C under normal pressure, densified into >=95% relative density to give the objective silicon nitride heat radiation member having 1-3 μm average diameter of major axis particle diameter of silicon nitride crystal in the section of sintered compact, 50-70% particle size distribution of the accumulation of crystal particles of <=1 μm particle diameter and >=50 W/m.K coefficient of thermal conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon nitride heat radiating member made of a silicon nitride sintered material which is applied to various insulating substrate materials such as a package for accommodating a semiconductor element, a heat sink material and the like, and a method of manufacturing the same. Has a thickness of 0.03
The present invention relates to an improvement for producing a thin heat radiating member having high thermal conductivity based on a sintered body of about 1.0 mm.

[0002]

2. Description of the Related Art In recent years, heat generated from a semiconductor device has been increasing along with high integration of a semiconductor element. In order to eliminate malfunction of the semiconductor device, such heat is quickly released to the outside of the device. Substrate is required.

However, alumina materials used in the past, such as various insulating substrates and packages for housing semiconductor elements, have a low thermal conductivity of about 20 W / m · K, and therefore have a high thermal conductivity as an alternative. Aluminum nitride has begun to attract attention. However, it has been found that aluminum nitride cannot be applied to parts that have low strength and fracture toughness and are subject to high stress and fields that require high reliability. Accordingly, silicon nitride sintered bodies have recently been receiving attention as a material that meets demands for high thermal conductivity, high strength, and high reliability.

Hitherto, silicon nitride sintered bodies have been actively studied as high-temperature structural materials for gas turbines and the like, and some of them have been put to practical use. Such a silicon nitride sintered body needs to be added with a rare earth element oxide in order to enhance the strength characteristics from room temperature to a high temperature and fired at a very high temperature of 1800 to 2000 ° C. In order to suppress the decomposition reaction of silicon nitride at a high temperature, it is necessary to perform firing in a nitrogen atmosphere at several tens to 100 atm.

On the other hand, when characteristics at high temperatures are not required, they are manufactured by adding alumina or magnesia as a sintering aid and firing at a relatively low temperature of 1700 to 1800 ° C.

[0006]

However, while silicon nitride is predicted to have high thermal conductivity due to its constituent elements and crystal structure, much less research has been done on a heat dissipating member than on a structural material. Was. Recently, it has been found that a silicon nitride sintered body as a high-temperature structural material has a considerably high thermal conductivity, and studies on a heat dissipating member of this sintered body have begun.

[0007] Due to such circumstances, most of the research on the heat dissipating member is based on the premise of sintering at a high temperature. For example, Japanese Patent Application Laid-Open Nos.
No. 88 mainly contains a rare earth element oxide as an auxiliary agent,
By firing at 800 to 2000 ° C. in a nitrogen pressurized atmosphere, a silicon nitride sintered body having a thermal conductivity of 60 W / m · K or more can be obtained. Further, Japanese Patent Application Laid-Open No.
No. 9731 contains 90% by weight or more of silicon nitride.
Both l and O are not more than 3.5% by weight, and the density is 3.15 g.
/ Cm ³ to obtain a silicon nitride sintered body having a thermal conductivity of 40 W / m · K or more.

However, since silicon nitride is decomposed at a high temperature of 1800 ° C. or higher, a special firing method of firing in a pressurized nitrogen gas atmosphere is employed to increase the density while suppressing the decomposition of silicon nitride. Therefore, the firing cost has been increased. Also, in the above firing method, it is difficult to completely suppress the decomposition of silicon nitride itself, and the burnt surface of the product is easily roughened. This has taken time and effort, which has contributed to an increase in cost.

More recently, Japanese Patent Application Laid-Open No. 8-319187
120 W / m.
A silicon nitride sintered body having a high thermal conductivity equal to or higher than that of aluminum nitride of K or more has also been proposed. However,
These are all fired at a high temperature exceeding 1800 ° C.
Alternatively, heat treatment after densification at a relatively low temperature causes a large crystal grain size in the silicon nitride sintered body to grow, thereby achieving high thermal conductivity. However, when such large crystal particles are present, there is a problem that the coarse particles serve as a destruction source and extremely reduce the strength as a sintered body.

On the other hand, firing of silicon nitride is performed for 1800 hours.
Normal pressure (atmospheric pressure) when performed at relatively low temperature below ℃
Can be fired in a non-oxidizing atmosphere, so that a product having a fine structure and having less roughened surface can be obtained. However, the conventional silicon nitride sintered body produced by firing at a low temperature of 1800 ° C. or lower has a problem that the thermal conductivity is extremely reduced to 20 to 30 W / m · K. This is mainly performed by using a rare earth oxide (RE ₂ O ₃ ) -Al ₂ O ₃ -based composite auxiliary agent in order to enhance the sinterability at a low temperature. It is considered that this is because the thermal conductivity of the silicon nitride crystal itself decreases due to the solid solution of Al atoms and the formation of sialon.

Further, addition of a sintering aid is indispensable for achieving low-temperature sinterability, and therefore, it is difficult to achieve the same thermal conductivity as aluminum nitride ceramics. In such a case, when the product is commercialized, the thickness of the heat dissipating member is reduced to reduce the thickness of the aluminum nitride (1).
A heat dissipating member having a thermal resistance substantially equal to that of a 50 W / mK level product can be provided.

However, when a silicon nitride heat radiation member is manufactured, it is usually molded and baked by a uniaxial press molding method, a casting molding method or the like. However, in such a molding method, the thickness is reduced. Since there is a limit in reducing the thickness, a sintered body having a small thickness has to be cut out from such a sintered body having a large thickness or obtained by polishing, resulting in an increase in cost.

One of the uses of the silicon nitride heat radiation member is a multilayer wiring board having a metallized wiring layer formed on the surface or inside thereof. In manufacturing such a multilayer wiring board, a raw material powder is contained. The slurry to be made is made into a very thin molded body by the doctor blade method, etc.
Although it is obtained by laminating and firing, the production of a silicon nitride green sheet has not been specifically studied so far, and the moldability is poor, and a green sheet having a thickness of 1 mm or less may be produced. It was difficult and at the same time it was very difficult to achieve both thermal conductivity.

Accordingly, the present invention has been made to solve the above-mentioned problems, and provides a silicon nitride heat radiation member having high thermal conductivity even in a structure based on a thin sintered body of 1 mm or less. The purpose is to do so.

The present invention is also directed to the production of a silicon nitride heat radiating member having excellent sheet formability and low-temperature sinterability, and having excellent high thermal conductivity for producing a multilayer structure such as a multilayer wiring board. It is intended to provide a method.

[0016]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors can improve the sheet formability by using a silicon nitride raw material powder having a specific particle size distribution. In addition, by controlling the particle size distribution of the silicon nitride crystal in the sintered body to a specific range, it is possible to produce a thin heat-dissipating member composed of a single layer or a laminated structure without performing cutting or polishing. And have led to the present invention.

That is, the silicon nitride heat dissipation member of the present invention is made of a sintered body having a relative density of 95% or more mainly composed of a silicon nitride columnar crystal, and a silicon nitride crystal on a cut surface of the sintered body. The average particle diameter of the major axis is 1 to 3 μm, the crystal particles having a particle diameter of 1 μm or less are cumulatively 50 to 70% in particle size distribution, and the thermal conductivity is 50 W / m · K or more. It is a feature.

The heat radiation member has a thickness of 0.03 to 0.03.
1.0mm single sintered body or single layer thickness 0.03 ~
The total thickness of the sintered body of 1.0 mm is 0.1 to 10 mm
It is also a great feature that the sintered body of the present invention has a three-point bending strength of 700 MPa or more at room temperature.

Further, according to the method for manufacturing a silicon nitride heat dissipation member of the present invention, the average particle diameter is 0.4 to 0.7 μm, the cumulative number of particles of 1 μm or less is 60 to 80%, and the cumulative 90% is 2%. An organic solvent and a binder are added to and mixed with a mixed powder composed of a silicon nitride powder having a particle size distribution of ５5 μm and a sintering aid, and the thickness after sintering is 0.03 to 1 by a sheet forming method using a slurry prepared. After being formed into a sheet so as to have a thickness of 0.08 mm, the formed body is appropriately laminated, and
It is characterized by firing under normal pressure for 3 to 6 hours in a non-oxidizing atmosphere at a temperature of not more than ℃ to densify to a relative density of 95% or more, and particularly to obtain a sintered body having a thickness of 0.1 to 10 mm. It is characterized by the following.

In the sintered body or the mixed powder, the rare earth element (RE) and Mg are contained in an amount of 4 to 30 mol% in terms of oxide, and the rare earth element (RE) and Mg are converted into oxide. Is preferably contained at a molar ratio (RE ₂ O ₃ / MgO) of 0.1 to 15.

According to the present invention, the average particle size is from 0.4 to
An organic solvent and a binder are added to a mixed powder of a silicon nitride powder and a sintering aid having a particle size distribution of 0.7 μm, 1 μm or less in a cumulative particle size of 60 to 80%, and a cumulative 90% of 2 to 5 μm. By forming a sheet using the slurry prepared by adding and mixing, a thickness of 0.03 to 1.
A thin sheet-shaped molded product of 0 mm can be produced.

Then, after appropriately laminating the molded body, 180
By firing and densifying at a temperature of 0 ° C. or less, the grain growth of the sintered particles is suppressed, and finally, the average diameter of the long axis particle diameter of the silicon nitride crystal on the cut surface of the sintered body is 1 to 1. 3 μm
And crystal particles having a particle size of 1 μm or less accumulate in an amount of 50 to 70
By controlling the structure to have a grain size distribution of%, strength reduction due to abnormal grain growth can be prevented and high thermal conductivity can be exhibited.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a heat radiating member of the present invention and a method of manufacturing the same will be described in detail.

The silicon nitride heat radiation member of the present invention is mainly composed of β-type silicon nitride columnar crystals, and has a relative density of 9%.
It is made of a dense sintered body of 5% or more, particularly 97% or more. Such denseness is important for achieving high thermal conductivity and high strength. If the relative density is lower than 95%, it is 50%.
It becomes difficult to achieve a thermal conductivity of W / m · K or more, and the strength also deteriorates.

In the sintered body, the average diameter of the major axis of silicon nitride crystal grains of the silicon nitride crystal grains at the cut surface is 1%.
It is important that it is 3 μm, preferably 1.5-2.5 μm. This is because if the average diameter is larger than 3 μm, coarse particles in the sintered body become a source of fracture and reduce the strength of the sintered body, and if the average diameter is smaller than 1 μm, the thermal conductivity is extremely reduced. This is because The average aspect ratio of the columnar silicon nitride crystal is 1.2 to 4, especially 1.5.
It is desirable to be 3.5 to simultaneously increase the high strength and high thermal conductivity of the sintered body.

Further, the silicon nitride sintered body of the present invention comprises:
It is important that the cumulative number of silicon nitride crystal grains having a grain size of 1 μm or less in the cross section is 50 to 70%. If the ratio is smaller than 50%, the strength is deteriorated, and if it is larger than 70%, the thermal conductivity is reduced. Preferably 5
5-65% is good.

Further, the sintered body for a silicon nitride heat dissipation member of the present invention contains an auxiliary component such as a sintering aid. In particular, it is desirable that the sintering aid contains a rare earth element and Mg. As rare earth elements, Y, La, Ce, Pr,
Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, E
Any of r, Tm, Yb, and Lu can be suitably used. Among them, Y, Ce, Sm, Dy,
Er, Yb, Lu, especially Y, Er are desirable in terms of characteristics and cost.

The rare earth element and Mg are specified in a total amount of 4 to 30 mol% in terms of oxide, and more preferably 5 to 20 mol%. Further, the molar ratio of the rare earth element and Mg in terms of oxide (RE ₂ O
₍₃ / MgO) must be in the range of 0.1 to 15, more preferably in the range of 0.5 to 13.

If the total amount is less than 4 mol%, the sinterability tends to be insufficient, and if the total amount exceeds 30 mol%, the proportion of silicon nitride in the sintered body decreases and the thermal conductivity decreases. To do that. If the molar ratio of RE ₂ O ₃ / MgO exceeds 15 or is smaller than 0.1, 1800
Densification at a temperature of not more than ° C. tends to be insufficient, and the thermal conductivity tends to decrease.

Although the compounding of an Al compound such as Al ₂ O ₃ contributes to the improvement of the sinterability, it dissolves in the Si ₃ N ₄ crystal and inhibits the diffusion of phonons. Since the conductivity is remarkably reduced, it is most preferable that the compound does not exist for the purpose of increasing the thermal conductivity.
It is desirably at most 0.5 mol%, preferably at most 0.5 mol%, more preferably at most 0.1 mol%, furthermore preferably at most 0.05 mol%.

The sintered body contains Ti, V, N for the purpose of improving mechanical properties and electrical properties or coloring.
at least one of metals belonging to Groups 4a, 5a and 6a of the Periodic Table such as b, W and Mo is 0.05 to 1% by weight in terms of oxide.
May be included.

In order to produce the silicon nitride heat radiation member of the present invention, the average particle diameter is 0.4 to 0.7 μm, the particles having a particle diameter of 1 μm or less are 60 to 80% in total and 90% in total are 2 to 2%.
It is important to use a silicon nitride powder having a particle size distribution of 5 μm. This means that particles of 1 μm or less are 60% cumulative
Less, or the average particle size is greater than 0.7 μm,
Alternatively, if the cumulative 90% exceeds 5 μm, it is difficult to densify to a relative density of 95% or more by firing at 1800 ° C. or less, and the particles of 1 μm or less cumulatively exceed 80%, or the average particle diameter exceeds 0.4 μm. Small or cumulative 9
If 0% is smaller than 2 μm, sheet molding becomes difficult, and even if the sheet is formed, cracks occur, and a molded article cannot be obtained.

In particular, a desirable range is that the average particle diameter is 0.1.
45 to 0.6 μm, particles of 1 μm or less are cumulatively 65 to 7
It is preferable to use a silicon nitride powder having a particle size distribution of 5% and a cumulative 90% of 2.5 to 4.0 μm.

Preferably, the silicon nitride powder has an impurity oxygen content of 0.5 to 3.0% by weight. This is because if the amount of impurity oxygen is more than 3.0% by weight, the surface of the sintered body may be roughened and the strength may be deteriorated. Further, it is desirable that the α ratio is 90% or more, particularly 95% or more, in order to enhance sinterability.

Rare earth element compounds, Mg compounds, and sometimes A
As described above, the composition of the compact using the compound 1 is such that the rare earth element and Mg are 4 to 30 mol% in total in terms of oxide,
In particular, it is 5 to 20 mol%, and the molar ratio (RE ₂ O ₃ / MgO) of the rare earth element and Mg in terms of oxide is 0.1 to 15,
In particular, it is contained so as to be in the range of 0.5 to 13, and
The Al content is preferably adjusted to 1.0 mol% or less, particularly 0.5 mol% or less, more preferably 0.1 mol% or less, further preferably 0.05 mol% or less in terms of oxide.

The rare earth element and M
g is added as an oxide powder having an average particle diameter of 1 μm or less and a purity of 99% or more, as well as a compound capable of forming an oxide by firing, such as carbonate and acetate.

After a slurry is prepared by adding an organic binder and a solvent to the mixed powder composed of the silicon nitride powder and the sintering aid powder blended as described above,
Using this slurry, according to a sheet-shaped forming method such as a doctor blade method or a rolling method, the thickness after firing is 0.03 m.
m or more, particularly 0.1 mm or more, and more preferably 0.3 mm or more. In addition, the thickness of the sheet-like molded body is determined by the shrinkage ratio due to firing (generally 75 to 85).
%) Can be determined as appropriate.

At this time, it is difficult to produce a sheet-like molded body having a thickness of less than 0.03 mm after firing. However, according to the present invention, by using the silicon nitride powder having the above specific particle size distribution, the thickness after firing is 1.0 mm or less, particularly 0.7 mm or less, and more preferably 0.5 mm or less.
It is possible to produce a sheet-shaped molded product having a thickness of not more than mm.

At this time, the slurry used is such that an organic binder such as an acrylic resin or a polyvinyl butyral resin is added in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the ceramic solid component.
Parts by weight, an organic solvent such as toluene or isopropyl alcohol is mixed at a ratio of 30 to 60 parts by weight, and the viscosity is 10 to 10 parts by weight.
Desirably, it is 50 poise.

Next, the molded body obtained as described above is subjected to a binder removal treatment in a weakly oxidizing atmosphere, and then, in a nitrogen-containing non-oxidizing atmosphere, at a temperature of 1800 ° C. or less, particularly 150 ° C.
The sintered body having a relative density of 95% or more can be produced by firing at a temperature of 0 to 1800 ° C., and further at 1600 to 1780 ° C. for 3 to 6 hours. If the baking time at this time is shorter than 3 hours, it is difficult to densify to a relative density of 95% or more.
If the time is exceeded, the grain growth in the sintered body is promoted, and the average long-axis particle diameter of the silicon nitride crystal exceeds 3 μm or 1 μm.
The accumulation of particles below m is less than 50% and the strength is reduced.

The silicon nitride radiating member of the present invention is based on a thin sintered body having a thickness of 1 mm or less after firing according to the above-described manufacturing method. The above-mentioned sheet-like molded body is appropriately laminated and pressed to adjust its thickness, fired at a time, and constituted by a laminated sintered body, so that it can be applied to products of all thicknesses.
However, when the thickness of the silicon nitride heat radiating member of the present invention exceeds 10 mm, the heat resistance of the member itself increases, so that high heat dissipation characteristics equivalent to that of aluminum nitride cannot be expected. Is 10 mm or less, especially 5 mm
Below, it is particularly desirable that it is 1 mm or less.

As a specific application of the heat radiation member of the present invention,
For example, it can be used as a heat sink member for a semiconductor element, and can be applied to an insulating substrate of a multilayer wiring board such as a wiring board in a package on which a semiconductor element is mounted.

In particular, when manufacturing a wiring substrate having a wiring layer formed on or in the insulating substrate, Cu, W, Mo-Mn, Mo, Pd-Ag is added to the surface of the sintered insulating substrate.
Or a conductor paste containing a high melting point metal such as tungsten or molybdenum is screen-printed on the surface of the green sheet having a thickness of 0.03 to 1.0 mm after sintering in the form of a circuit pattern. Alternatively, a through hole may be formed in a green sheet using a microdrill or a laser, and the hole may be filled with the conductive paste, followed by simultaneous firing under the same conditions as described above.

[0044]

The oxygen content was 1.0% by weight and the α-form content was 93%.
%, Silicon nitride raw material powders manufactured by various direct nitriding methods having particle size distributions as shown in Tables 1 and ₂ , and Er ₂ O
₃ is 5 mol%, MgO is 8 mol%, Al ₂ O ₃ is 0.2
% Of MoO _{3 and} 0.5% by weight of MoO _{3. To} 100 parts by weight of the mixed powder, 20 parts by weight of an acrylic resin and 50 parts by weight of toluene were added as a molding binder. To obtain a slurry having a viscosity of 30 poise.

Using this slurry, a green sheet having a thickness of 0.6 mm after sintering was produced by a doctor blade method. The prepared green sheets were subjected to an appearance inspection to check for cracks and the like. Then, the green sheets were laminated and pressure-bonded and cut to produce a disk-shaped laminated molded body having a diameter of 12 mm and a thickness of 5 mm. Also, for strength measurement, 60 × 6 ×
A 4 mm rectangular parallelepiped laminated molded body was produced.

After debinding the thus obtained molded body in a weakly oxidizing atmosphere at a predetermined temperature, it is fired in a nitrogen atmosphere at normal pressure under the firing conditions shown in Tables 1 and 2 to obtain a silicon nitride sintered body. It was prepared and used as a sample for evaluation.

Using the evaluation sample, the density of the silicon nitride sintered body was first measured by the Archimedes method, and the ratio (relative density) to the theoretical density was calculated. Then, the thermal conductivity (sample thickness 3 mm) was measured by a laser flash method. Further, the three-point bending strength of the burnt skin surface at room temperature was measured according to JISR1601.

The particle size distribution of the silicon nitride crystal particles was determined by mirroring any cut surface of the obtained sintered body,
_{After the} grain boundary phase was etched in the mixed acid of No. ₃ , an SEM photograph was taken and determined by image analysis processing using Luzex. The results are shown in Tables 1 and 2.

[0049]

[Table 1]

[0050]

[Table 2]

As shown in Tables 1 and 2, the sample of the present invention
Each of them was densified to a relative density of 95% or more, and had excellent properties of a thermal conductivity of 50 W / m · K or more and a three-point bending strength of 700 MPa or more.

On the other hand, in Sample No. 1 in which the accumulation of particles of 1 μm or less of the silicon nitride powder is less than 60%, the accumulation ratio of the sintered body of 1 μm or less is less than 50% and 1%.
At 750 ° C., it could not be sufficiently densified, and both thermal conductivity and strength were low.

Sample No. 5 in which the above-mentioned accumulation in the powder exceeds 80%, Sample No. 6 in which the average particle size is smaller than 0.4 μm, and Sample No. 10 in which the 90% -accumulation particle size is smaller than 2 μm. In each case, generation of fine cracks was observed in the green sheet.

Further, in Sample No. 13 in which the 90% cumulative particle diameter of the powder is larger than 5 μm, the long axis average diameter of the sintered body becomes smaller than 1 μm, the densification becomes insufficient, and the thermal conductivity and strength are reduced. Decreased. In samples Nos. 14 and 15 having a firing time shorter than 3 hours, the relative density and thermal conductivity were low due to insufficient sintering. In samples 18 and 19 having a firing time longer than 6 hours, abnormal grain growth was observed. Therefore, the strength deteriorated. Further, the sample No. having a firing temperature exceeding 1800 ° C.
In No. 23, the silicon nitride was severely decomposed, and the characteristics could not be evaluated.

[0055]

As described above in detail, according to the present invention, a slurry prepared by adding and mixing an organic solvent and a binder to a mixed powder comprising a silicon nitride powder having a specific particle size distribution and a sintering aid. By forming a sheet using the above, a thin sheet-shaped formed body having a thickness of 0.03 to 1.0 mm can be produced. Then, after appropriately laminating the compact, the compact is fired at a temperature of 1800 ° C. or less and densified, thereby suppressing the grain growth of the sintered particles, and finally, the silicon nitride crystal on the cut surface of the sintered body. The average diameter of the long axis particle diameter is 1 to 3 μm, and the crystal grain having a particle diameter of 1 μm or less is controlled to have a structure having a particle size distribution of 50 to 70% in a cumulative manner, thereby preventing a decrease in strength due to abnormal grain growth and increasing the strength. A heat dissipating member having thermal conductivity can be manufactured.

As a result, a thin sintered body having a reduced thermal resistance can be easily manufactured without cutting or polishing, and a package such as a heat sink or a semiconductor element mounted package or a multilayer wiring board can be easily manufactured. It can be applied as a circuit board.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Okayama 1-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Yasuhiko Yoshihara 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Kyocera 4G001 BA03 BA06 BA08 BA12 BA32 BA73 BB03 BB06 BB08 BB12 BB32 BC12 BC13 BC56 BD03 BD14 BE03 BE22 BE32 4G052 AB04

Claims (7)

[Claims] 1. A sintered body mainly composed of silicon nitride columnar crystals having a relative density of 95% or more, wherein the average diameter of the major axis of the silicon nitride crystal on the cut surface of the sintered body is 1 to 3 μm. 50 to 70% in total of crystal particles having a particle size of 1 μm or less
A silicon nitride heat dissipation member, characterized by having a particle size distribution of, and having a thermal conductivity of 50 W / m · K or more. 2. A single sintered body having a thickness of 0.03 to 1.0 mm or a sintered body having a single layer thickness of 0.03 to 1.0 mm having a total thickness of 0.1 to 10 mm. 2. The heat-dissipating silicon nitride member according to claim 1, wherein the heat-dissipating member comprises a laminated sintered body. 3. The silicon nitride heat radiation member according to claim 1, wherein the three-point bending strength of the sintered body at room temperature is 700 MPa or more. 4. The sintered body has a rare earth element (RE) and Mg in a total amount of 4 to 30 mol% in terms of oxide, and a molar ratio (R) of the rare earth element (RE) and Mg in terms of oxide.
E ₂ O ₃ / MgO) is silicon nitride radiator member according to claim 1, characterized in that it contains a proportion to be 0.1-15. 5. An average particle diameter of 0.4 to 0.7 μm, 1 μm
The following particles have a cumulative value of 60 to 80% and a cumulative value of 90:
% After sintering by a sheet forming method using a slurry prepared by adding an organic solvent and a binder to a mixed powder comprising a silicon nitride powder having a particle size distribution of 2 to 5 μm and a sintering aid. After being formed into a sheet so as to have a thickness of 03 to 1.0 mm, the formed body is appropriately laminated, and
A method for producing a silicon nitride-based heat radiation member, characterized in that the member is baked at normal pressure in a non-oxidizing atmosphere at a temperature of not more than 00C and baked for 3 to 6 hours to densify it to a relative density of 95% or more. 6. The method according to claim 5, wherein a sintered body having a thickness of 0.1 to 10 mm is obtained. 7. The mixed powder contains a rare earth element (RE) and Mg in a total amount of 4 to 30 mol% in terms of oxides, and a molar ratio (RE) of the rare earth element (RE) and Mg in terms of oxides. ₂ O ₃ / MgO) is the method according to claim 5, wherein the silicon nitride radiator member, characterized in that it contains a proportion to be 0.1-15.