TW201934195A - Method for manufacturing heat radiation sheet, heat radiation sheet, substrate, power semiconductor module - Google Patents

Abstract

The present invention provides a method for manufacturing a heat dissipation sheet having heat conductivity, wherein heat conductivity in the thickness direction is enhanced. This method for manufacturing a heat dissipation sheet is provided with a baking step for heating so as to polymerize a polymerizable compound while applying pressure, from the top-bottom direction with respect to the thickness of the heat dissipation sheet, to a composition including an inorganic filler, the polymerizable compound, and a curing agent for curing the polymerizable compound.

Description

Manufacturing method of heat sink, heat sink, substrate and power semiconductor module

The invention relates to a method for manufacturing a heat sink. In particular, it relates to a method for manufacturing a heat sink having excellent thermal conductivity in the thickness direction.

In recent years, semiconductor components for power control such as hybrid cars and electric vehicles, or central processing units (CPUs) for high-speed computers have been desired in order to prevent the temperature of the internal semiconductors from becoming too high. High thermal conductivity of wafers and packaging materials. That is, the ability to efficiently release heat generated from a semiconductor wafer to the outside becomes important.

As a method for solving such a heat radiation problem, a method of contacting a highly thermally conductive material (radiation member) with a heat-generating portion, and dissipating heat to the outside to dissipate heat can be mentioned. As a heat radiating member, in terms of excellent workability or insulation, the development of a heat radiating member including a resin composite material in which an inorganic material is compounded with a resin and high thermal conductivity is being developed.

High thermal conductivity of resin composites is generally achieved by adding a large amount of metal fillers or inorganic fillers to general resins such as polyethylene resins, polyamide resins, polystyrene resins, acrylic resins, and epoxy resins. . However, the thermal conductivity of an inorganic filler is a value inherent in a substance, and the upper limit has been determined. Therefore, attempts have been made to increase the thermal conductivity of general-purpose resins to increase the thermal conductivity of resin composites. Patent Document 1 discloses the following: In a heat dissipating member including a polymer having a fixed molecular arrangement, which is obtained by orienting and polymerizing a liquid crystal source of a polymerizable compound having liquid crystallinity in a predetermined direction, if When compounded with a specific highly thermally conductive inorganic filler (highly thermally conductive inorganic filler), a resin composite with extremely high thermal conductivity in the alignment direction can be obtained through the synergistic effect of the combination (paragraph 0007).

Furthermore, in the case of using a polymerizable liquid crystal compound or a plate-shaped or needle-shaped filler to produce a heat sink, the raw material flows in the plane direction of the sheet in the pressing method or the extrusion method. When the alignment is performed in the plane direction, the thermal conductivity in the plane direction becomes very high. However, there are cases where the thermal conductivity in the vertical (thickness) direction of the sheet is lower than in the non-aligned state. Therefore, in order to form the non-orientation state, an attempt was also made to agglomerate the plate-shaped filler to produce desert rose-like secondary particles and composite the secondary particles with a resin, thereby increasing the verticality of the sheet. The amount of fillers aligned in the (thickness) direction to improve thermal conductivity (Patent Document 2, paragraph 0013, Patent document 3, paragraph 0223, refer to Patent document 4, paragraph 0170). However, it is difficult for the resin component to penetrate into the inside of the secondary particles and the voids become large. As a result, there is also a problem that the thermal conductivity is reduced. Furthermore, if the secondary particles are excessively enlarged, it becomes more difficult for the resin component to penetrate into the interior, and the gap between the large fillers also becomes large. Therefore, there is also a problem that the thermal conductivity is not improved as expected.

In recent years, particularly in the field of power semiconductors, it is important to improve the efficiency of conducting heat between the power semiconductor element and the heat sink or water-cooling device, which are arranged to sandwich the insulating substrate, through the insulating substrate, thereby improving the efficiency. Thermal conductivity of the insulating substrate in the vertical (thickness) direction. [Prior Art Literature] [Patent Literature]

[Patent Literature 1] International Publication No. 2015/170744 [Patent Literature 2] Japanese Patent Laid-Open No. 2015-189609 [Patent Literature 3] Japanese Patent Laid-Open No. 2017-036190 [Patent Literature 4] Japanese Patent Laid-Open No. 2006-265527 number

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a method for manufacturing a heat sink having thermal conductivity and improving thermal conductivity in a vertical (thickness) direction. [Means for solving problems]

In view of the flow direction of the polymerizable liquid crystal compound, the inventors of the present invention focused on filling the polymerizable liquid crystal compound into a filler including a large-diameter secondary particle formed by agglomeration of the flat plate particles, and reducing the amount to the inorganic material and resin. In order to improve the thermal conductivity, voids generated between the inorganic material and the resin in the composite. As shown in FIG. 1, when the resin component is penetrated into the large-diameter secondary particle filler, the liquid resin component penetrates from the surface of the filler toward the inner direction, so that a radial flow occurs in the inner direction. That is, since the resin component is permeated and polymerized in a state aligned in a direction perpendicular to the surface of the ball, an effect of improving the thermal conductivity in a direction perpendicular to the surface of the ball, that is, in a direction penetrating the ball is expected. Especially in the case of a liquid crystal compound, since the thermal conductivity in the alignment direction is very high, this effect is large, and further high thermal conductivity can be expected. The inventors have found that during the manufacturing process of the heat sink, the liquid crystal can be aligned or the void can be reduced as shown in FIG. 2 by a combination of compression molding, heating treatment, and vacuum during the calcination or polymerization. (Filling the void or suppressing the generation of voids), as a result, the thermal conductivity in the thickness direction can be improved, and the present invention has been completed.

The method for manufacturing a heat sink according to the first embodiment of the present invention is a method for manufacturing a heat sink, which includes a firing step that includes an inorganic filler, a polymerizable compound, and a hardener that hardens the polymerizable compound. The composition is heated by applying pressure from a direction that becomes a vertical direction with respect to the thickness of the heat sink, and polymerizing the polymerizable compound. With such a structure, pressure can be continuously applied to the composition during polymerization to reduce internal voids. As a result, the manufactured heat sink can have high thermal conductivity in the thickness direction.

The method for manufacturing a heat sink according to a second embodiment of the present invention is the method for manufacturing a heat sink according to the first embodiment of the present invention, which further includes a vacuum step, which is performed before the calcination step in order to The polymerizable compound is allowed to penetrate into the filler or the gap between the fillers, apply pressure to the composition from a direction that becomes the up-down direction, and place the composition in a vacuum environment; the calcination step is performed at A step of applying pressure to the composition in a vacuum environment and heating the composition in a direction from the vertical direction. The "vacuum" means "a state in a space filled with a gas having a pressure lower than atmospheric pressure". With such a structure, pressure can be continuously applied to the composition during polymerization in a vacuum environment to further reduce internal voids. As a result, the manufactured heat sink can have higher thermal conductivity in the thickness direction. Furthermore, the density of the sheet can be increased, and the strength of the sheet can be increased.

The method for manufacturing a heat sink according to a third embodiment of the present invention is the method for manufacturing a heat sink according to the second embodiment of the present invention, and further includes a temporary forming step before the vacuum step. Applying pressure to the composition in a direction from the vertical direction under atmospheric pressure, and heating the polymerizable compound at a temperature lower than a polymerization temperature to perform compression molding. With such a configuration, when the polymerizable compound has liquid crystallinity, the liquid crystal compound can be aligned when the composition is pressed to make it strong.

A method for manufacturing a heat sink according to a fourth embodiment of the present invention is a method for manufacturing a heat sink, which includes a temporary forming step of hardening a polymer compound containing an inorganic filler, a polymerizable compound, and a polymerizable compound under atmospheric pressure or a vacuum environment. The composition of the hardener is applied with pressure in a direction that is vertical to the thickness of the heat sink, and is heated below the polymerization temperature by compression-molding the polymerizable compound; a vacuum step is performed at After the temporary forming step, in order to make the polymerizable compound penetrate into the filler or the gap between the fillers, the composition is placed in a vacuum environment; and a calcination step is performed on the composition in a vacuum environment so that The polymerizable compound is heated while being polymerized. With this configuration, the internal voids can be reduced by polymerization in a vacuum environment, and as a result, the manufactured heat sink can have high thermal conductivity in the thickness direction. Furthermore, the density of the sheet can be increased, and the strength of the sheet can be increased.

The method for manufacturing a heat sink according to a fifth embodiment of the present invention is the method for manufacturing a heat sink according to any one of the first to fourth embodiments of the present invention, wherein the inorganic filler includes a first inorganic filler and a pellet. A second inorganic filler having a diameter smaller than that of the first inorganic filler, and a mixing ratio of the first inorganic filler and the second inorganic filler is such that the filling ratio when the space ratio between the fillers is minimized is set to 100% The ratio is 70% or more, and the first inorganic filler is secondary particles obtained by aggregating needle-like or plate-like particles. Furthermore, the first inorganic filler and the second inorganic filler may be the same compound or different compounds. With such a configuration, small particles enter into the spaces between the large particles, so that the particles can be filled more densely, and the spaces in the sheet can be further reduced. Furthermore, by reducing the space ratio between the fillers and the synergistic effect of the production method of the present invention, the thermal conductivity in the thickness direction can be further improved.

The method for manufacturing a heat sink according to a sixth embodiment of the present invention is the method for manufacturing a heat sink according to any one of the first to fifth embodiments of the present invention, wherein the inorganic filler is formed of a nitride, and The polymerizable compound is a polymerizable liquid crystal compound having a structure containing an oxetanyl group or an oxetanyl group at both ends, and a heating temperature in the firing step is at least a temperature range in which the polymerizable liquid crystal compound exhibits a liquid crystal phase. The "temperature range in which a liquid crystal phase is displayed" refers to a temperature range in which a nematic phase, a smectic phase, or a cholesterol phase is displayed. With such a configuration, the polymerizable liquid crystal compound can cause alignment in a fluid state, and can further polymerize the polymerizable liquid crystal compound in an aligned state (a state in which molecules are aligned in a specific direction) and harden together with the inorganic filler. Therefore, the heat sink can have high thermal conductivity through the synergistic effect of the thermal conductivity of the polymerized liquid crystal compound and the thermal conductivity of the inorganic filler formed of the nitride.

The method for manufacturing a heat sink according to a seventh embodiment of the present invention is the method for manufacturing a heat sink according to the sixth embodiment of the present invention, which includes the following steps: the temporary forming step or the calcination During the step temperature rise, the polymerizable liquid crystal compound stays for 1 second or longer in the development temperature region of the liquid crystal phase of the polymerizable liquid crystal compound. In this way, it is necessary to form a liquid crystal state during heating and harden it after alignment, thereby improving thermal conductivity.

The method for manufacturing a heat sink according to an eighth embodiment of the present invention is the method for manufacturing a heat sink according to the sixth or seventh embodiment of the present invention, which further includes an alignment process step, and the alignment process step is Before the temporary forming step and the calcining step, an alignment treatment of the composition is performed. With such a configuration, the polymerizable liquid crystal compound can be easily aligned.

The method for manufacturing a heat sink according to a ninth embodiment of the present invention is the method for manufacturing a heat sink according to any of the sixth to eighth embodiments of the present invention, wherein the polymerizable liquid crystal compound is the following formula (1 -1) at least one compound represented by. R ^a1 -Z- (AZ) _m1 -R ^a1 ･ ･ ･ (1-1) [In the formula (1-1), R ^a1 is the following formula (2-1) to formula (2-2) A polymerizable group represented by any of: A is 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,4-phenylene, naphthalene-2,6-diyl, tetrahydro Naphthalene-2,6-diyl, fluorene-2,7-diyl, bicyclic [2.2.2] octane-1,4-diyl, or bicyclic [3.1.0] hex-3,6-diyl, in In these rings, any -CH ₂ -may be substituted by -O-, any -CH = may be substituted by -N =, and any hydrogen may be substituted by halogen, alkyl group having 1 to 10 carbon atoms, or carbon number 1 ~ 10 halogenated alkyl substitution. In this alkyl, any -CH ₂ -may be substituted by -O-, -CO-, -COO-, or -OCO-, and any -CH ₂ CH ₂ -may be substituted by -CH = CH-, or -C≡C- substitution; Z is a single bond, or an alkylene group having 1 to 20 carbon atoms. In this alkylene group, any -CH ₂ -can be passed through -O-, -S-, -CO-, -COO-, or -OCO- substitution, any -CH ₂ CH ₂ -can be via -CH = CH-, -CF = CF-, -CH = N-, -N = CH -, -N = N-, or -C≡C- substitution, any hydrogen may be substituted by halogen; m1 is an integer from 1 to 6] [化 1] [In the formulae (2-1) to (2-2), R ^b is hydrogen, halogen, -CF ₃ , or an alkyl group having 1 to 5 carbon atoms, and q is 0 or 1] If constituted as described above, The composition may contain a compound more preferably as a polymerizable liquid crystal compound. These compounds are thermosetting and harden without being affected by the amount of the filler, and further have excellent heat resistance. In addition, since the molecular structure has symmetry and linearity, it is considered to be advantageous for phonon conduction.

The method for manufacturing a heat sink according to a tenth embodiment of the present invention is the method for manufacturing a heat sink according to the ninth embodiment of the present invention, wherein in the formula (1-1), A is a 1,4-ring ring Hexyl, 1,4-cyclohexyl with any hydrogen substituted by halogen, 1,4-phenylene, 1,4-phenyl with any hydrogen substituted by halogen or methyl, fluorene-2,7-di Or fluorene-2,7-diyl in which any hydrogen is substituted with halogen or methyl. With such a structure, the composition may contain a compound which is further preferable as the polymerizable liquid crystal compound. The molecules of these compounds have a higher linearity and are considered to be more favorable for phonon conduction.

The method for manufacturing a heat sink according to an eleventh embodiment of the present invention is the method for manufacturing a heat sink according to the tenth embodiment of the present invention, wherein in the formula (1-1), Z is a single bond,-(CH ₂ ) _a- , -O (CH ₂ ) _a -,-(CH ₂ ) _a O-, -O (CH ₂ ) _a O-, -CH = CH-, -C≡C-, -COO-,- OCO-, -CH = CH-COO-, -OCO-CH = CH-, -CH ₂ CH ₂ -COO-, -OCO-CH ₂ CH _2- , -CH = N-, -N = CH-,- N = N-, -OCF ₂ -or -CF ₂ O-, and a is an integer of 1-20. With such a configuration, the composition may contain a compound particularly preferable as the polymerizable liquid crystal compound. These compounds are preferable because they are excellent in physical properties, easy to manufacture, or easy to handle.

The method for manufacturing a heat sink according to a twelfth embodiment of the present invention is the method for manufacturing a heat sink according to any one of the first to eleventh embodiments of the present invention, wherein the inorganic filler is selected from the group consisting of boron nitride and nitrogen. At least one of aluminum nitride and silicon nitride. With such a structure, the composition may contain a compound more preferably as an inorganic filler.

A method of manufacturing a heat sink according to a thirteenth embodiment of the present invention is the method of manufacturing a heat sink according to any one of the first to twelfth embodiments of the present invention, wherein the hardener is the following formula (3-1 At least one diamine compound. H ₂ NZ- (AZ) _m2 -NH ₂ ･ ･ ･ (3-1) [In the formula (3-1), A is 1,4-cyclohexyl, or 1,4-phenylene, and Arbitrary hydrogen of these rings may be substituted by halogen or alkyl having 1 to 10 carbons; Z is a single bond or an alkylene having 1 to 10 carbons; m2 is an integer of 1 to 7] Then, the composition may contain a compound more preferably as a hardener. Especially when m2 is an even number, it is preferable that the diamine compound can be hardened without hindering the liquid crystallinity of the polymerizable liquid crystal compound.

The method for manufacturing a heat sink according to a fourteenth embodiment of the present invention is the method for manufacturing a heat sink according to any one of the first to thirteenth embodiments of the present invention, wherein the inorganic filler is a filler treated with a silane coupling agent. Or a filler surface-modified with the polymerizable compound after a silane coupling treatment. The "surface modification" refers to a silane coupling agent in which a polymerizable compound is further bonded to a filler. With such a configuration, the filler subjected to the silane coupling treatment or the surface-modified filler can form a bond with another polymerizable compound or another silane coupling agent in the composition, and thus can improve thermal conductivity.

The heat sink of the fifteenth embodiment of the present invention is formed of a composition including a polymerizable liquid crystal compound having a structure containing an oxetanyl group or an oxetanyl group at both ends; and polymerizing the polymerizable liquid crystal compound. A hardening agent that hardens a liquid crystal compound; and an inorganic filler formed of a nitride, in the heat sink, the inorganic filler includes a first inorganic filler and a second inorganic filler having a particle size smaller than the first inorganic filler, The mixing ratio of the first inorganic filler and the second inorganic filler is a ratio where the filling ratio when the space ratio between the fillers is the smallest is 100%, and the filling ratio becomes 70% or more. The first inorganic filler is Secondary particles formed by acicular or plate-shaped particles, the thickness of the heat sink is 200 μm to 1000 μm, and the thermal conductivity in the thickness direction of the heat sink exceeds 20 W / mK. With this structure, a heat sink having high thermal conductivity in the thickness direction can be obtained.

A substrate according to a sixteenth embodiment of the present invention includes: the heat sink of the fifteenth embodiment of the present invention; and a metal plate laminated on at least one side of the heat sink. With such a configuration, even if the heat sink is formed thinner in order to improve the thermal conductivity of the sheet, the mechanical strength can be secured by the metal plate.

A power semiconductor module according to a seventeenth embodiment of the present invention includes a power semiconductor substrate including the heat sink of the fifteenth embodiment of the present invention as an insulating substrate, and a conductor circuit formed on the heat sink; and A power semiconductor wafer is disposed on the power semiconductor substrate and is electrically connected to the conductor circuit. The inorganic filler is boron nitride. With this configuration, the heat sink becomes an insulating substrate, and the heat generated in the power semiconductor module can be efficiently released by the excellent thermal conductivity in the thickness direction. [Effect of the invention]

The heat sink manufactured by the manufacturing method of the heat sink of this invention has high thermal conductivity, and especially the thermal conductivity in the thickness direction is extremely excellent compared with the heat sink manufactured by the prior art.

This application is based on Japanese Patent Application No. 2017-239025 filed in Japan on December 13, 2017, and its content forms part of the content of this application. The present invention can be more fully understood from the following detailed description. The further application range of this invention will become clear by the following detailed description. However, the detailed description and specific examples are ideal embodiments of the present invention, and are described only for explanation. The reason is that, based on the detailed description, those skilled in the art will understand various changes and modifications within the spirit and scope of the present invention. The applicant does not intend to present any of the recorded embodiments to the public, and those who change or replace the statements in the case that may not be included in the scope of the patent application are also made part of the invention under the equality theory.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the same or similar parts are denoted by the same or similar symbols in each drawing, and repeated explanations are omitted. The present invention is not limited to the following embodiments.

The terms used in this manual are as follows. A "liquid crystal compound" and a "liquid crystal compound" are compounds which exhibit a nematic phase or a smectic liquid crystal phase.

The meaning of a sentence such as "arbitrary -CH ₂ -in the alkyl group may be substituted with -O-, etc." or "arbitrary -CH ₂ CH ₂ -may be substituted with -CH = CH-, etc." For example, any of -CH ₂ -substituted with -O- or -CH = CH- in C ₄ H ₉ -is C ₃ H ₇ O-, CH ₃ -O- (CH ₂ ) _2- , CH ₃ -O-CH ₂ -O- and the like. Similarly, any of -CH ₂ CH ₂ -substituted with -CH = CH- in C ₅ H ₁₁ -is H ₂ C = CH- (CH ₂ ) _3- , CH ₃ -CH = CH- (CH ₂ ) ₂ -etc., and further any -CH ₂ -substituted with -O- is CH ₃ -CH = CH-CH ₂ -O- and the like. Thus the term "arbitrary" means "at least one selected without distinction". Furthermore, in consideration of the stability of the compound, CH ₃ -O-CH ₂ -O-, which is not adjacent to oxygen, is preferable to CH ₃ -OO-CH _2- , which is adjacent to oxygen.

In addition, regarding ring A, the phrase "arbitrary hydrogen may be substituted with halogen, alkyl having 1 to 10 carbon atoms, or halogenated alkyl having 1 to 10 carbon atoms" means, for example, 2,4-phenylene Embodiments in which at least one hydrogen at positions 3, 5, and 6 are substituted with a substituent such as fluorine or methyl, and embodiments in which the substituent is a "halogenated alkyl group having 1 to 10 carbon atoms" include Examples are 2-fluoroethyl or 3-fluoro-5-chlorohexyl.

The "compound (1-1)" means a liquid crystal compound represented by the following formula (1-1), and sometimes means at least one of the compounds represented by the following formula (1-1). When a compound (1-1) has multiple A's, any two A's may be the same or different. When multiple compounds (1-1) have A, any two A's may be the same or different. This rule also applies to other symbols and bases such as R ^a1 or Z.

[Composition I for Heat Radiation Sheet] A composition (hereinafter, referred to as a composition I) used in the method for producing a heat radiation sheet of the present invention will be described. However, the composition described below is an example, and the composition used in the present invention is not limited to this. The composition for a heat sink may further include: a polymerizable liquid crystal compound having a structure containing an oxetanyl group or an oxetanyl group at both ends; a hardener for hardening the polymerizable liquid crystal compound; and a nitride. Inorganic filler. The curing temperature of the composition I is at least the temperature range in which the polymerizable liquid crystal compound exhibits a liquid crystal phase and the temperature range in which the isotropic phase is exhibited. By using the liquid crystal phase of the polymerizable liquid crystal compound, it is possible to form a resin phase that is polymerized (cured) in a state where the molecular order is aligned. Heat can flow through aligned molecules and inorganic fillers arranged along the alignment, so that high thermal conductivity can be obtained in the alignment direction.

<Polymerizable Liquid Crystal Compound> Examples of the polymerizable liquid crystal compound include a liquid crystal compound represented by the following formula (1-1). The compound (1-1) has a liquid crystal skeleton and a polymerizable group, has high polymerization reactivity, a wide liquid crystal phase temperature range, and good miscibility. When the compound (1-1) is mixed with another liquid crystal compound, a polymerizable compound, or the like, the compound (1-1) tends to be easily uniform. R ^a1 -Z- (AZ) _m1 -R ^a1 (1-1)

By appropriately selecting the terminal group R ^a1 , the ring structure A, and the bonding group Z of the compound (1-1), physical properties such as a liquid crystal phase expression region can be arbitrarily adjusted. The effects of the types of the terminal group R ^a1 , the ring structure A, and the bonding group Z on the physical properties of the compound (1-1), and preferable examples thereof will be described below.

· A terminal group at the end group R ^a1 case where R ^a1 is a linear alkyl group, a wide temperature range of liquid crystal phase and a small viscosity. On the other hand, when R ^a1 is a branched alkyl group, compatibility with other liquid crystal compounds is good. In R ^a1 is cyano, halogen, -CF _3, -OCF ₃ of the case, also showed good liquid crystal phase temperature range, high dielectric anisotropy, having a moderate compatibility.

Examples of preferred R ^a1 include: hydrogen, fluorine, chlorine, cyano, -N = C = O, -N = C = S, alkyl, alkoxy, alkoxyalkyl, and alkoxyalkane Oxy, alkylthio, alkylthioalkoxy, alkenyl, alkenyloxy, alkenylalkyl, alkoxyalkenyl, alkynyl, alkynyloxy and the like. Among these groups, a group in which at least one hydrogen is substituted with halogen is also preferable. Preferred halogens are fluorine and chlorine, and still more preferably fluorine. Specific examples include monofluoroalkyl, polyfluoroalkyl, perfluoroalkyl, monofluoroalkoxy, polyfluoroalkoxy, perfluoroalkoxy, and the like. From the viewpoint of the phonon's easy conductivity, that is, the easy transfer of heat, these groups are more preferably linear than branched chains.

Further preferable examples of R ^a1 include hydrogen, fluorine, chlorine, cyano, -CF ₃ , -CF ₂ H, -CFH ₂ , -OCF ₃ , -OCF ₂ H, alkyl group having 1 to 10 carbon atoms, An alkoxy group having 1 to 10 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, and the like. Examples of the alkyl group, alkoxy group, and alkoxyalkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and methyl. Oxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonoxy, decoxy, methoxymethyl, methoxyethyl Wait. Particularly preferred R ^a1 is an alkyl group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms.

· Ring structure A When at least one ring in ring structure A is 1,4-phenylene, the orientation order parameter and the magnetization anisotropy are large. In addition, when at least two rings are 1,4-phenylene, the temperature range of the liquid crystal phase is wide, and the transparent point is high. When at least one hydrogen on a 1,4-phenylene ring is substituted with cyano, halogen, -CF ₃ or -OCF ₃ , the dielectric constant anisotropy is high. In addition, when at least two rings are 1,4-cyclohexyl, the transparent point is high and the viscosity is small.

As preferred A, 1,4-cyclohexyl, 1,4-cyclohexenyl, 2,2-difluoro-1,4-cyclohexyl, 1,3-dioxane- 2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1 1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2,3,5-trifluoro-1,4-phenylene, pyridine-2,5-diyl, 3- Fluoropyridine-2,5-diyl, pyrimidine-2,5-diyl, pyridazine-3,6-diyl, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene -2,7-diyl, 9-methylfluorene-2,7-diyl, 9,9-dimethylfluorene-2,7-diyl, 9-ethylfluorene-2,7-diyl, 9-fluorofluorene-2,7-diyl, 9,9-difluorofluorene-2,7-diyl, etc.

Regarding the stereo configuration of 1,4-cyclohexyl and 1,3-dioxane-2,5-diyl, the trans is better than the cis. Since the structures of 2-fluoro-1,4-phenylene and 3-fluoro-1,4-phenylene are the same, the latter is not exemplified. This rule also applies to the relationship between 2,5-difluoro-1,4-phenylene and 3,6-difluoro-1,4-phenylene.

Further preferred A is 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2- Fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4 -Phenylene etc. Particularly preferred A is 1,4-cyclohexyl and 1,4-phenylene.

Bonding group Z is a single bond to bonding group Z,-(CH ₂ ) _2- , -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH = CH-, In the case of -CF = CF- or-(CH ₂ ) _4- , especially a single bond,-(CH ₂ ) _2- , -CF ₂ O-, -OCF _2- , -CH = CH- or-( In the case of CH ₂ ) _4- , the viscosity becomes small. When the bonding group Z is -CH = CH-, -CH = N-, -N = CH-, -N = N-, or -CF = CF-, the temperature range of the liquid crystal phase is wide. When the bonding group Z is an alkyl group having about 4 to 10 carbon atoms, the melting point is lowered.

Examples of preferred Z include a single bond,-(CH ₂ ) ₂ -,-(CF ₂ ) _2- , -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH = CH-, -CF = CF-, -C≡C-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) ₃ -,-(CH ₂ ) ₂ COO-, -OCO (CH ₂ ) _2- , -CH = CH-COO-, -OCO-CH = CH-, and the like.

Further preferred Z include a single bond,-(CH ₂ ) _2- , -COO-, -OCO-, -CH ₂ O-, -OCH _2- , -CF ₂ O-, -OCF _2- , -CH = CH-, -C≡C-, etc. Particularly preferred Z is a single bond,-(CH ₂ ) _2- , -COO-, or -OCO-.

When the compound (1-1) has three or less rings, the viscosity is low, and when it has three or more rings, the transparent point is high. In addition, in this specification, a six-membered ring and a condensed ring including a six-membered ring are basically regarded as a ring. For example, a three-membered ring or a four-membered ring and a five-membered ring are not considered as a ring. A condensed ring such as a naphthalene ring or a fluorene ring is regarded as one ring.

The compound (1-1) may be optically active or optically inert. In the case where the compound (1-1) is optically active, the compound (1-1) has a case having an asymmetric carbon and a case having an asymmetric axis. The stereo configuration of the asymmetric carbon may be R or S. The asymmetric carbon may be located on either R ^a1 or A, and if it has an asymmetric carbon, the compatibility of the compound (1-1) is good. When the compound (1-1) has an asymmetric axis, the twist-inducing force is large. In addition, any of the optical rotation properties may be used. As described above, by appropriately selecting the type of the terminal group R ^a1 , the ring structure A and the bonding group Z, and the number of rings, a compound having a desired physical property can be obtained.

Compound (1-1) The compound (1-1) can also be represented by the following formula (1-a) or (1-b). PY- (AZ) _m -R ^a (1-a) PY- (AZ) _m -YP (1-b)

In the formulae (1-a) and (1-b), A, Z, and R ^a have the same meanings as A, Z, and R ^a1 defined by the formula (1-1), and P represents the following formula (2-1) to the polymerizable group represented by formula (2-2), Y represents a single bond or an alkylene group having 1 to 20 carbon atoms, preferably an alkylene group having 1 to 10 carbon atoms, and the alkylene group In the group, any -CH ₂ -may be substituted by -O-, -S-, -CO-, -COO-, -OCO-, or -CH = CH-. Particularly preferred Y is a -CH ₂ -O-substituted alkylene group at one or both ends of an alkylene group having 1 to 10 carbon atoms. m is an integer of 1 to 6, preferably an integer of 2 to 6, and more preferably an integer of 2 to 4.

Examples of the preferable compound (1-1) include the compounds (a-1) to (g-20) shown below.

[Chemical 2]

[Chemical 3]

[Chemical 4]

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In the chemical formula (a-1) to the chemical formula (g-20), R ^a , P, and Y are as defined in the formula (1-a) and the formula (1-b). Z ¹ is a single bond,-(CH ₂ ) ₂ -,-(CF ₂ ) ₂ -,-(CH ₂ ) _4- , -CH ₂ O-, -OCH ₂ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -CH = CHCOO-, -OCOCH = CH-,-(CH ₂ ) ₂ COO-, -OCO (CH ₂ ) _2- , -C≡C-, -C≡C-COO-, -OCO-C≡C-, -C≡C-CH = CH-, -CH = CH-C≡C- , -CH = N-, -N = CH-, -N = N-, -OCF ₂ -or -CF ₂ O-. Furthermore, a plurality of Z ¹ may be the same or different.

Z ² is-(CH ₂ ) ₂ -,-(CF ₂ ) ₂ -,-(CH ₂ ) _4- , -CH ₂ O-, -OCH ₂ -,-(CH ₂ ) ₃ O-, -O ( CH ₂ ) _3- , -COO-, -OCO-, -CH = CH-, -CF = CF-, -CH = CHCOO-, -OCOCH = CH-,-(CH ₂ ) ₂ COO-, -OCO ( CH ₂ ) _2- , -C≡C-, -C≡C-COO-, -OCO-C≡C-, -C≡C-CH = CH-, -CH = CH-C≡C-, -CH = N-, -N = CH-, -N = N-, -OCF ₂ -or -CF ₂ O-.

Z ³ is a single bond, an alkyl group having 1 to 10 carbon atoms,-(CH ₂ ) _a- , -O (CH ₂ ) _a O-, -CH ₂ O-, -OCH _2- , -O (CH ₂ ) ₃ -,-(CH ₂ ) ₃ O-, -COO-, -OCO-, -CH = CH-, -CH = CHCOO-, -OCOCH = CH-,-(CH ₂ ) ₂ COO-, -OCO ( CH ₂ ) _2- , -CF = CF-, -C≡C-, -CH = N-, -N = CH-, -N = N-, -OCF ₂ -or -CF ₂ O-, multiple Z ³ can be the same or different. a is an integer of 1-20.

X is a substituent of 1,4-phenylene and fluorene-2,7-diyl in which any hydrogen may be substituted with halogen, alkyl, or fluorinated alkyl, and represents halogen, alkyl, or fluorinated alkyl.

A more preferred embodiment of the compound (1-1) will be described. A more preferable compound (1-1) can be represented by the following formula (1-c) or (1-d). P ¹ -Y- (AZ) _m -R ^a (1-c) P ¹ -Y- (AZ) _m -YP ¹ (1-d) In the formula, A, Y, Z, R ^a and m As defined above, P ¹ represents a polymerizable group represented by the following formulae (2-1) to (2-2). In the case of the formula (1-d), two P ¹ represent the same polymerizable group (2-1) to polymerizable group (2-2), two Y represent the same group, and two Y are Bonded in a way that becomes symmetrical.

[Chemical 16]

More specific examples of the compound (1-1) are shown below.

[Chemical 17]

[Chemical 18]

[Chemical 19]

-Method for synthesizing compound (1-1) The compound (1-1) can be synthesized by a combination of methods known in organic synthetic chemistry. Methods for introducing target end groups, ring structures, and bonding groups into starting materials, such as Houben-Weyl (Methods of Organic Chemistry), Georg Thieme Verlag, Stuttgart), Organic Syntheses (John Wily & Sons, Inc.), Organic Reactions, John Wily & Sons Inc .)), Comprehensive Organic Synthesis (Pergamon Press), New Experimental Chemistry Lecture (Maruzen) and other books are recorded. Also, refer to Japanese Patent Laid-Open No. 2006-265527.

<Hardener> Examples of preferred hardeners are shown below. Examples of the amine-based hardener include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, o-xylenediamine, m-xylenediamine, p-xylenediamine, and trimethylhexamethylenediamine. Amine, 2-methylpentamethylenediamine, diethylaminopropylamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis (4-amino-3 -Methylcyclohexyl) methane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane, 3,9-dipropylamine-2,4,8,10 -Tetraoxaspiro [5,5] undecane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, o-phenylenediamine , M-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylphosphonium, polyoxypropylenediamine, polyoxypropylenetriamine, polycyclohexylpolyamine, N-aminoethylpiperazine Wait. In particular, a diamine is preferable because it can harden the polymerizable liquid crystal compound without hindering the liquid crystallinity of the polymerizable liquid crystal compound. The amount of the curing agent may be appropriately selected depending on the epoxy equivalent or the oxetane equivalent.

<Inorganic filler> Examples of the inorganic filler include nitrides such as aluminum nitride, boron nitride, and silicon nitride that can be used as a filler with high thermal conductivity. Can also be diamond, graphite, silicon carbide, silicon, beryllium oxide, magnesium oxide, aluminum oxide, zinc oxide, silicon oxide, copper oxide, titanium oxide, cerium oxide, yttrium oxide, tin oxide, oxide ', bismuth oxide, cobalt oxide , Calcium oxide, aluminum nitride, boron nitride, silicon nitride, magnesium hydroxide, aluminum hydroxide, gold, silver, copper, platinum, iron, tin, lead, nickel, aluminum, magnesium, tungsten, molybdenum, stainless steel, etc. Inorganic filler and metal filler. Examples of the shape of the filler include a spherical shape, an amorphous shape, a fibrous shape, a rod shape, a tube shape, and a plate shape. The shape of the filler is preferably a shape in which alignment is easily caused by the flow, such as a plate shape or a needle shape, and these agglomerates are easy to effectively exhibit the characteristics of liquid crystals, and are therefore preferred. The type, shape, size, and addition amount of the filler can be appropriately selected according to the purpose. When the obtained heat sink requires insulation, it may be a conductive filler if the desired insulation is maintained.

Preferred are boron nitride and aluminum nitride. Particularly preferred is hexagonal boron nitride (h-BN) or aluminum nitride. Boron nitride and aluminum nitride are preferable because the thermal conductivity in the plane direction is very high, the dielectric constant is also low, and the insulation is also high. In addition, if the plate-shaped filler is aligned in the plate-like direction, the thermal conductivity in the horizontal direction increases, but the thermal conductivity in the vertical direction (thickness direction) decreases. Therefore, secondary particles, such as desert rose, are preferably formed by agglomerating fillers such as spherical, amorphous, needle-like (fibrous, rod-like), cylindrical, and plate-like fillers.

The inorganic filler can also be directly used without modification (Figure 3 left). If an unmodified inorganic filler is used, the preparation steps can be reduced, so it is preferable. Alternatively, a surface treated with a coupling agent may be used (center in FIG. 3). For example, as shown in FIG. 3, boron nitride (h-BN) is treated with a silane coupling agent. In the case of boron nitride, since there is no reactive group in the plane of the particle, a silane coupling agent is bonded only around the particle. It is thought that boron nitride treated with a silane coupling agent can form a bond with the polymerizable liquid crystal compound having a specific bonding group in the composition via the silane coupling agent, and this bond contributes to heat conduction. The silane coupling agent preferably reacts with an oxetanyl group or a hardening agent, and is therefore preferably an amine system or has an oxetanyl group at the terminal. For example, Sila-Ace S310, Sila-Ace S320, Sila-Ace S330, Sera-Ace manufactured by JNC (Sila-Ace) S360, Sila-Ace S510, Sila-Ace S530, etc.

The inorganic filler can also be treated with a silane coupling agent and then surface-modified with a polymerizable liquid crystal compound (Figure 3 right). For example, as shown in FIG. 3, a boron nitride (h-BN) treated with a silane coupling agent is surface-modified with a polymerizable liquid crystal compound. It is considered that boron nitride surface-modified with a polymerizable liquid crystal compound can form a bond with the polymerizable liquid crystal compound in the composition, and this bond contributes to heat conduction.

The inorganic filler may be a particle having a large particle size (first inorganic filler), and a particle having a small particle size (second inorganic filler) is added and mixed. By mixing and filling, small particles enter into the spaces between the large particles, so that the particles can be filled more densely, and the spaces can be further reduced. The first inorganic filler is preferably the secondary particle, and the second inorganic filler is only required to have a particle diameter smaller than that of the first inorganic filler, and may be a secondary particle or a primary particle. Furthermore, in the two-component mixed filling, if the large particles and the small particles are filled at the mixing ratio (volume ratio or weight ratio) that can be the most densely packed, it can help reduce voids and is better. . The average particle size of the large particles is preferably 10 μm to 1000 μm, more preferably 10 μm to 500 μm, and even more preferably 25 μm to 500 μm.

In the two-component mixed filling, the space ratio (gap between particles) changes due to the mixing ratio. The mixing ratio that can become the smallest space ratio (closest packing) can be known by methods such as "Suzuki Doro," The effect of particle physical properties on dense packing of powders ", Journal of Powder Engineering Society, Powder Engineering Society , 2003, Vol. 40, No. 5, p22-28 ". Specifically, the space ratio (ε) can be obtained by the following two expressions. In the following two formulas, ε1 and ε2 are individual space ratios of large and small particles, and SV1 and SV2 are volume-based mixing fractions of large and small particles. ε = 1- (1-ε1) / SV1 ε = 1- (1-ε2) / {1- (SV2 × ε2)} uses the space ratio calculated by the two expressions of Furnas ( ε) to determine the mixing ratio. Regarding the content of the inorganic filler, if the filling rate is 100% when the densest packing is performed at the mixing ratio that can be the closest packing (when the space ratio (ε) is the smallest), the filling rate is preferably 70%. The above amount is more preferably an amount of 80% or more, further preferably an amount of 90% or more, and most preferably 100%. The same applies to the filling of one component and the mixed filling of two or more components. As for the mixing ratio at a preferable filling ratio, a large value of the space ratio (ε) calculated by the two expressions of Furnas is used, and the space ratio and the mixing ratio (volume ratio or weight) are used. Ratio, etc.). Furthermore, the inorganic filler may have three or more components or irregularly shaped particles and a particle size distribution. The mixing ratio that can be the most densely packed can be achieved by a known method, for example, refer to "Suzuki Doro," Space ratio of a three-component particle random packing layer ", Proceedings of Chemical Engineering, Society of Chemical Engineering, 1984, Vol. 10 , No. 6, p721-727 "," Suzuki Doro, "Space ratio of random packing layer of multi-component particles with particle size distribution", Proceedings of Chemical Engineering, Society of Chemical Engineering, 1985, Vol. 11, No. 4 No., p438-443 ".

<Other components> The composition I used in the present invention is composed of at least one of the compounds (1-1) and compounded with an inorganic filler as a highly thermally conductive inorganic filler. The composition may include two or more compounds (1-1), and may also include a combination of at least one compound (1-1) and at least one compound other than compound (1-1). The constituent elements other than the compound (1-1) are not particularly limited, and examples thereof include polymerizable compounds (hereinafter also referred to as "other polymerizable compounds") other than the compound (1-1), and non-polymerizable liquid crystal properties. Compounds, polymerization initiators, and solvents.

<Non-polymerizable liquid crystal compound> The composition I used in the present invention may include a liquid crystal compound having no polymerizable group as a constituent element. Examples of such non-polymerizable liquid crystal compounds are available in a liquid crystal database (LiqCryst, LCI Publisher GmbH, Hamburg, Germany), etc. as a library of liquid crystal compounds. Record. By polymerizing the composition containing a non-polymerizable liquid crystal compound, a composite material of a polymer of the compound (1-1) and a liquid crystal compound can be obtained. In such a composite material, for example, a non-polymerizable liquid crystal compound is present in a polymer mesh such as a polymer dispersed liquid crystal.

<Polymerization initiator> The composition I used in the present invention may have a polymerization initiator as a constituent element. The polymerization initiator may be, for example, a photoradical polymerization initiator, a photocationic polymerization initiator, a thermal radical polymerization initiator, or the like according to the polymerization method of the composition. Examples of preferred initiators for thermal radical polymerization include benzamidine peroxide, diisopropyl peroxydicarbonate, tert-butyl peroxy-2-ethylhexanoate, and triperoxide. Tert-butyl methyl acetate, di-tertiary butyl peroxide (DTBPO), tertiary butyl diisobutyrate, lauryl peroxide, dimethyl 2,2'-azobisisobutyrate Ester (MAIB), azobisisobutyronitrile (AIBN), azobiscyclohexanecarbonitrile (ACN), etc.

<Solvent> The composition I used in the present invention may contain a solvent. The polymerization of the composition may be performed in a solvent, or may be performed without a solvent. The composition containing a solvent may be applied to a substrate by, for example, a spin coating method, and then the solvent may be removed to perform photopolymerization. In addition, it may be heated to an appropriate temperature after photo-curing, and post-treatment may be performed by thermal curing. Examples of preferred solvents include benzene, toluene, xylene, mesitylene, hexane, heptane, octane, nonane, decane, tetrahydrofuran, γ-butyrolactone, and N-methylpyrrolidine. Ketones, dimethylformamide, dimethylmethylene, cyclohexane, methylcyclohexane, cyclopentanone, cyclohexanone, propylene glycol monomethyl ether acetate (PGMEA), etc. . The solvents may be used singly or in combination of two or more kinds. Furthermore, it does not make much sense to limit the use ratio of the solvent during the polymerization, as long as the polymerization efficiency, the cost of the solvent, the energy cost, and the like are taken into consideration and determined separately for each case.

<Others> Since the compound (1-1) has high polymerizability, a stabilizer may be added in order to facilitate handling. As such a stabilizer, a known one can be used without limitation, and examples thereof include hydroquinone, 4-ethoxyphenol, and 3,5-di-third-butyl-4-hydroxytoluene (BHT). Further, in order to adjust the viscosity or color of the composition I, additives (such as oxides) may be added. Examples include fine powders of titanium oxide to form white, carbon black to form black, and silicon dioxide to adjust viscosity. In order to further increase the mechanical strength, additives may be added. Examples include inorganic fibers or cloths such as glass and carbon fibers, or fibers or long molecules such as polyvinyl formaldehyde, polyvinyl butyral, polyester, polyamide, and polyimide as polymer additives. In addition, in order to improve reliability, additives such as an antioxidant and a lightfastener may be added.

[Composition for heat sink II] The composition used in the method for producing a heat sink of the present invention may be a polymerizable compound (other polymerizable compound) other than at least one compound (1-1), and may be used as A composite of inorganic fillers of a highly thermally conductive inorganic filler (hereinafter, referred to as composition II). Such a polymerizable compound is preferably a compound that does not lower film formability and mechanical strength. The polymerizable compound is classified into a compound having no liquid crystallinity and a compound having liquid crystallinity. Examples of the polymerizable compound having no liquid crystal properties include a vinyl derivative, a styrene derivative, a (meth) acrylic acid derivative, a sorbic acid derivative, a fumaric acid derivative, an itaconic acid derivative, and the like. The composition II can be the same component as the composition I except that a polymerizable compound having no liquid crystallinity is used instead of the polymerizable liquid crystal compound.

[Manufacturing method of composition] <When performing a coupling treatment and surface modification of a polymerizable liquid crystal compound> When using an inorganic filler treated with a coupling agent, a coupling treatment is performed on the inorganic filler. For the coupling treatment, a known method can be used. As an example, first, inorganic filler particles and a coupling agent are added to a solvent. Stir using a stirrer or the like and let stand. After the solvent is dried, heat treatment is performed under a vacuum condition using a vacuum dryer or the like. A solvent is added to the inorganic filler particles, and the particles are pulverized by ultrasonic treatment. This solution was separated and purified using a centrifugal separator. After discarding the supernatant, the same operation was performed several times by adding a solvent. The purified inorganic filler particles are dried using an oven. Next, the coupling-treated inorganic filler particles and the polymerizable liquid crystal compound are mixed with an agate mortar or the like, and then kneaded with a biaxial roller or the like. Thereafter, separation and purification were performed by ultrasonic treatment and centrifugation. After further mixing the amine hardener with an agate mortar or the like, the mixture is kneaded with a biaxial roller or the like. Thereby, the composition I which does not contain a solvent can be obtained.

[Manufacturing method of heat sink] As an example, the manufacturing method of the heat sink according to the first embodiment of the present invention will be specifically described using the composition I containing no solvent. The method for producing a heat sink of the present invention includes a firing step, and the firing step is heating at a temperature at which the polymerizable liquid crystal compound contained in the composition I is polymerized. (1) Put the composition I containing no solvent into the mold of a compression molding machine, and apply pressure (press) under the atmospheric pressure in a vertical direction relative to the thickness of the finished fins to form a compressed state. (Solid state). It should be noted that the direction that becomes the vertical direction with respect to the thickness of the fins after finishing is the direction of the arrow in FIG. 4. (2) Pressure is applied to the composition I in a solid state and the temperature is gradually increased to thereby orient the molecular flow of the polymerizable liquid crystal compound. After the temperature rises to the polymerization temperature, the composition I is polymerized by maintaining the temperature (calcination step) ). Or (1) Put the composition I containing no solvent into the mold of a compression molding machine, and apply pressure (press) under the atmospheric pressure from the direction of the up-down direction relative to the thickness of the finished heat sink to form a compressed State (solid state). Since compression is performed before evacuation, scattering of particles contained in the composition I is preferably suppressed. (2) A pressure is applied to the composition I in a solid state, and it is evacuated by placing it in a vacuum oven at room temperature (vacuum step). (3) In a vacuum environment, pressure is applied to the composition I in a solid state and the temperature is gradually increased to thereby orient the molecular flow of the polymerizable liquid crystal compound. After the temperature rises to the polymerization temperature, the temperature is maintained to make the composition I Polymerization is carried out (calcination step).

As an example, the manufacturing method of the heat sink of the 2nd Embodiment of this invention is demonstrated using composition I which does not contain a solvent. The method for manufacturing a heat sink of the present invention includes a temporary forming step and a firing step. The temporary forming step is performed by heating the composition at a temperature for compression molding. The firing step is performed by polymerizing the polymerizable liquid crystal compound contained in the composition I. The temperature is heated. (1) Put the composition I containing no solvent into the mold of a compression molding machine, apply pressure (press) under the atmospheric pressure from the direction of up-down relative to the thickness of the finished heat sink, and at the polymerization temperature Next, heating is performed to form a compressed state (solid state) (temporary forming step). (2) A pressure is applied to the composition I after the temporary forming step, and the resultant is placed in a vacuum oven to be evacuated (vacuum step). (3) In a vacuum environment, pressure is applied to the composition I after the temporary forming step, and the temperature is gradually increased, so that the molecular flow alignment of the polymerizable liquid crystal compound is maintained, and the temperature is maintained after the temperature rises to the polymerization temperature. The composition I is polymerized by heating (calcination step). Or (1) Put the composition I containing no solvent into the mold of a compression molding machine, and apply pressure (press) under the atmospheric pressure or vacuum environment from the direction of the thickness of the finished heat sink to the vertical direction. Then, heating is performed to form a compressed state (solid state) (temporary forming step). (2) Put no pressure on the composition I after the temporary forming step, and put it into a vacuum oven to evacuate (vacuum step). (3) Slowly increase the temperature in a vacuum environment, thereby orienting the molecular flow of the polymerizable liquid crystal compound, maintain the temperature after the temperature rises to the polymerization temperature, and polymerize the composition I after the temporary molding step by heating ( Calcination step).

Since the polymerizable liquid crystal compound is subjected to alignment molding by compression molding, it is preferable to perform alignment molding and polymerization at a temperature range above the temperature range in which the liquid crystal phase is displayed to form a polymer, which is preferable. The pressure to be applied to the composition I may be a range in which the mold is not damaged, and examples thereof include 5 MPa to 500 MPa. The pressure during compression is basically preferably high. However, it is preferable to appropriately change according to the strength of the mold or the target physical properties (in which direction the thermal conductivity is important, etc.), and to apply an appropriate pressure. The pressure applied during the temporary forming and the firing may be the same or different. The temperature during heating may be a temperature at which the composition can be compression-molded in the temporary molding step and the calcination step, and the polymerizable liquid crystal compound can be more easily immersed in the void in a vacuum state. Hold or maintain the liquid crystal state. In addition, the firing step varies depending on the polymerizable liquid crystal compound in the composition, and it may take time to heat linearly, may be heated at a specific temperature for a specific time, or may be heated stepwise at a specific temperature for a specific time. As long as it is a heating method which accelerates a polymerization reaction as described above, it is appropriately selected depending on the constituent elements of the composition. The time for which the liquid crystal state is retained or held is preferably 1 second to 4 hours, more preferably 1 second to 1 hour, and even more preferably 1 second to 30 minutes. The pressure during vacuum is basically preferably low. For example, the vacuum is 0.1 MPa or less, preferably 1 KPa or less, more preferably 100 Pa or less, and even more preferably 10 Pa or less.

As described above, the composition is combined with compression and heated under atmospheric pressure or vacuum to manufacture a heat sink. It is considered that the production method of the present invention can suppress the generation of voids in the heat sink, and the generated voids can be filled with the resin in the composition, and as a result, the thermal conductivity in the vertical (thickness) direction can be improved.

As an example, the manufacturing method of the heat sink of 3rd Embodiment of this invention is demonstrated concretely using the composition I containing a solvent. (1) The composition I is coated on a substrate and the solvent is dried and removed to form a coating film layer having a uniform film thickness. Examples of the coating method include spin coating, roll coating, curtain coating, flow coating, printing, microgravure coating, gravure coating, line coding, dip coating, spray coating, and meniscus coating. .

The drying and removal of the solvent can be performed, for example, by air-drying at room temperature, drying by a hot plate, drying by a drying furnace, and blowing by warm air or hot air. The conditions for removing the solvent are not particularly limited, as long as it is dried until the solvent is substantially removed, and the fluidity of the coating film layer disappears. Furthermore, depending on the type and composition ratio of the compound used in the composition I, the molecular alignment of the liquid crystal molecules in the coating film layer may be completed during the process of drying the coating film layer. However, in order to make the alignment of the liquid crystal molecules in the coating film layer more uniform, it is preferable to perform heat treatment and polymerization treatment on the coating film layer after the drying step to fix the alignment. Therefore, the steps after the drying step can be the same as when the composition containing no solvent is used.

Examples of the polymerization method of the composition I include radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization. In order to fix the molecular arrangement or the helical structure, it is suitable to use electron beam, ultraviolet light, Thermal or photopolymerization of light or heat such as visible light or infrared rays (hot rays). The thermal polymerization is preferably performed in the presence of a radical polymerization initiator, and the photopolymerization is preferably performed in the presence of a photoradical polymerization initiator. In addition, depending on the content of the inorganic filler, thermal polymerization using heat is preferred. The obtained polymer may be any of a homopolymer, a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer, and may be appropriately selected depending on the application and the like.

It is also possible to perform an alignment treatment on the substrate surface before coating the composition I. As a method for performing an alignment treatment on the substrate surface, for example, a method of using a vertical alignment agent for a liquid crystal display on a substrate, and the like.

[Heat Sink] FIG. 2 is an image diagram of a heat sink when boron nitride is used as the inorganic filler. The heat sink of the fourth embodiment of the present invention has a thermal conductivity exceeding 20 W / mK in the thickness direction. The thermal conductivity is preferably 25 W / mK or more, and more preferably the thermal conductivity is 30 W / mK or more. Such a heat sink can be manufactured by the manufacturing method of the heat sink of the said 1st-3rd embodiment.

A polymer obtained by controlling and polymerizing composition I containing at least one compound (1-1) has high thermal conductivity in the alignment direction, and a sheet produced by the method for producing a heat sink of the present invention Furthermore, it can have excellent thermal conductivity in the thickness direction.

The polymer obtained by polymerizing the composition I containing at least one compound (1-1) is preferably a thermosetting resin. When the compound (1-1) having a polymerizable group at both ends is used, a thermosetting resin is easily obtained. The thermosetting resin has a three-dimensional crosslinked structure. Since such a polymer is insoluble in a solvent, the molecular weight cannot be measured. However, in the case where the heat sink is obtained by applying the composition I on the substrate to fix the molecular alignment and polymerize it, the molecular weight is not a problem because no further processing is performed, as long as the conditions are satisfied in the use environment. can. In order to further increase the molecular weight, a crosslinking agent may be added. Thereby, a polymer excellent in chemical resistance and heat resistance can be obtained. As such a crosslinking agent, a known one can be used without limitation, and examples thereof include tris (3-mercaptopropionate).

The polymer obtained by controlling and polymerizing the composition I containing at least one compound (1-1) has a characteristic that the molecular orientation is fixed in an arbitrary direction. In this way, by fixing the liquid crystal molecules of the liquid crystal molecules as uniformly as possible in a certain direction, a polymer having high thermal conductivity in the alignment direction can be obtained. The alignment direction can be arbitrarily controlled by aligning liquid crystal molecules before polymerization.

Furthermore, by laminating films arranged in a certain direction in each direction, high thermal conductivity in all directions can be achieved. Such a laminated structure can also be formed by repeating the process of "application of the composition → polymerization → application of the composition → polymerization". Forming the laminated structure in this manner is also useful for alleviating the anisotropy of the mechanical strength of the obtained heat sink. In addition, the film arranged in a certain direction may be cut out, and the film may be arranged so that the film is aligned in the vertical direction, thereby improving the thermal conductivity in the thickness direction of the film.

In addition to the sheet, the heat sink of the present invention may be used in the shape of a film, a film, a fiber, a molded body, or the like. The thickness of the heat sink of the present invention is 5 μm or more, preferably 10 μm to 1000 μm, and more preferably 20 μm to 500 μm. The thickness may be appropriately changed according to the application. For example, the heat sink of the present invention can also be used as an adhesive sheet having excellent thermal conductivity, and the thickness in this case is several tens of μm. When a heat sink is used as an insulating substrate for a semiconductor, the thickness is several hundred μm. In this way, the heat sink of the present invention can also be used as a heat sink substrate, a heat sink film, a heat sink adhesive sheet, and a heat sink molded product.

[Substrate] A substrate according to a fifth embodiment of the present invention includes the heat sink and the metal plate of the fourth embodiment. Examples of the substrate including a heat sink and a metal plate include a combination of a heat sink and a heat sink, or a combination of a heat sink and a metal electrode. Examples of the metal plate include copper, aluminum, nickel, gold, nickel-plated copper, and gold-plated copper.

[Power semiconductor module] A power semiconductor module according to a sixth embodiment of the present invention includes a power semiconductor substrate including the heat sink of the fourth embodiment as an insulating substrate, and a conductor formed on the heat sink. A circuit; and a power semiconductor wafer, which is disposed on the power semiconductor substrate and is electrically connected to the conductor circuit. The heat sink of the present invention has high heat resistance and high insulation in addition to high thermal conductivity. Therefore, the power semiconductor module is particularly effective for, for example, an insulated gate bipolar transistor (IGBT) module that requires a more efficient heat dissipation mechanism due to high power. IGBT is one of the semiconductor components. It is a bipolar transistor formed by combining a metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) into the gate, which can be used for power control applications. Electronic devices including IGBTs include main converter elements of high-power inverters, non-stop power supply devices, variable voltage and frequency control devices for AC motors, control devices for railway vehicles, hybrid vehicles, and trams. Electric conveyors, induction heat (IH) conditioners, etc. [Example]

Hereinafter, the present invention will be described in detail using examples. However, the present invention is not limited to the contents described in the following examples.

The component materials used in the examples of the present invention are as follows. <Inorganic filler> · Boron nitride h-BN particles, manufactured by Momentive Performance Materials Japan (commercial), (brand name) PolarTherm PTX-25, PolarTherm PT -670 · Boron nitride, manufactured by Japan 3M Corporation, Platelets 003 <Polymerizable liquid crystal compound> · Polymerizable oxelanyl compound, manufactured by JNC Corporation, as follows Formula (1) (1) <Amine-based hardener> · 4,4'-ethylenediphenylamine, manufactured by Tokyo Chemical Industry Co., Ltd. <silane coupling agent> · N- (2-aminoethyl) -3-aminopropyltrimethylamine Oxysilane, manufactured by JNC (stock), (brand name) Sila-Ace S320 [Chem. 21]

<Example 1> The production amount of the inorganic filler mixture was 0.774 g of Compound (1) manufactured by JNC Corporation and 0.223 with 4,4'-diamino-1,2-diphenylmethane. g, put in an agate mortar, grind thoroughly, and mix. The weight ratio of this mixture is calculated | required from epoxy equivalent and active hydrogen equivalent of an amine. This mixture is called mixture A. Put 0.997 g of this mixture A and 5 g of PTX-25 in an aluminum container, and stir and heat on a hot plate at 55 ° C. for 10 minutes. This is called a PTX-25 mixture. In addition, 55 ° C is the temperature at which the compound (1) manufactured by JNC Corporation becomes a liquid crystal state. Similarly, 0.997 g of mixture A and 5 g of PT-670 were treated in the same manner. This is called a PT-670 mixture. Measure 0.1 g of the PTX-25 mixture and 0.82 g of the PT-670 mixture separately and mix thoroughly. PTX-25 and PT-670, which have different particle sizes, determine the mixing ratio and content so that the space ratio between the particles is the smallest (so that it is the most densely packed).

Forming and polymerization As shown in Fig. 4, the obtained mixture of the PTX-25 mixture and the PT-670 mixture was sandwiched in a mold through which the shape of the heat sink was cut out, and the mold was sandwiched by an aluminum thick plate from above and below. Bolts hold the aluminum plates to each other. The M16 bolt was tightened with a torque wrench at 30 N · m, and the mixture existing in the mold was pressed under atmospheric pressure. In a pressurized state, a square vacuum thermostatic dryer (trade name DP300) manufactured by Yamato Scientific was used to heat the component at a pressure of 0.1 KPa or less and a temperature of 150 ° C for 15 hours to produce a heat dissipation member. At this time, the temperature rise rate in the mold from 23 ° C to 150 ° C was about 0.5 ° C / min, and it took about 30 minutes to pass through the temperature range of the liquid crystal state of the compound (1) manufactured by JNC Corporation. . Finally, it reached 150 ° C, and polymerization was performed while maintaining the temperature.

<Example 2> In Example 1, PTX-25 and PT-670 having different particle diameters were mixed at a mixing ratio in which the space ratio between the particles was the smallest (closest packing). If this filling ratio is set to 100%, in Example 2, PTX-25 and PT-670 are mixed so that the filling ratio becomes 70%. Except that, a heat sink was produced in the same manner as in Example 1.

<Example 3> 10 g of boron nitride (PolarTherm PTX-25 manufactured by Momentive Performance Materials Japan) was combined with a silane coupling agent (JNC) (stock 1 g of S320 manufactured) was added to 100 mL of toluene, and stirred at 500 rpm for 1 hour using a stirrer, and the obtained mixture was dried at 40 ° C for 4 hours. Furthermore, after drying the solvent, a vacuum dryer set at 120 ° C. was used, and heat treatment was performed under vacuum for 5 hours. Let the obtained particles be filler A. Filler A is a particle in a state where an inorganic filler is modified with a silane coupling agent. A heat sink was produced in the same manner as in Example 1 except that the filler A was replaced with PTX-25 of Example 1.

<Example 4> The obtained mixture of the PTX-25 mixture and the PT-670 mixture was sandwiched between molds, and pressurized to 30 MPa using a compression molding machine (IMC-19EC manufactured by Imoto Manufacturing Co., Ltd.) set at 150 ° C. , Heating for 10 minutes, thereby temporarily molding under atmospheric pressure. Further, as shown in FIG. 4, the obtained fins after the temporary forming were clamped in a mold cut out into a shape of a fin, and the mold was sandwiched by an aluminum thick plate from above and below, and the aluminum plates were fixed to each other with M16 bolts. . The M16 bolt was tightened with a torque wrench at 30 N · m, and the mixture existing in the mold was pressed under atmospheric pressure. In a state of pressure and pressing, a square vacuum constant temperature dryer (trade name DP300) manufactured by Yamato Scientific was used to heat the fins at a pressure of 0.1 KPa or less and a temperature of 150 ° C. for 15 hours. At this time, the temperature rise rate in the mold from 23 ° C to 150 ° C was about 0.5 ° C / min, and it took about 30 minutes to pass through the temperature range of the liquid crystal state of the compound (1) manufactured by JNC Corporation. . Finally, it reached 150 ° C, and polymerization was performed while maintaining the temperature.

<Example 5> As shown in FIG. 4, the obtained mixture of the PTX-25 mixture and the PT-670 mixture was sandwiched in a mold cut into a shape of a heat sink, and the mold was sandwiched by an aluminum thick plate from above and below. M16 bolts hold the aluminum plates to each other. The M16 bolt was tightened with a torque wrench at 30 N · m, and the mixture existing in the mold was pressed under atmospheric pressure. In a state of pressure and pressing, a square vacuum constant temperature dryer (trade name DP300) manufactured by Yamato Scientific was used to heat the fins at 150 ° C for 15 hours under an atmospheric pressure environment. At this time, the temperature rise rate in the mold from 23 ° C to 150 ° C was about 0.5 ° C / min, and it took about 30 minutes to pass through the temperature range of the liquid crystal state of the compound (1) manufactured by JNC Corporation. . Finally, it reached 150 ° C, and polymerization was performed while maintaining the temperature.

<Example 6> In Example 1, PTX-25 and PT-670 having different particle diameters were mixed at a mixing ratio in which the space ratio between the particles was the smallest (closest packing). If this filling rate is 100%, in Example 6, PTX-25 and PT-670 were mixed so that the filling rate would become 70%. This mixture was measured so that the thickness became 230 μm. As in Example 4, as shown in FIG. 4, the obtained mixture of the PTX-25 mixture and the PT-670 mixture was sandwiched into a mold cut through a shape of a heat sink, and the mold was sandwiched into the mold from above and below , Fix the aluminum plates to each other with M16 bolts. The M16 bolt was tightened with a torque wrench at 30 N · m, and the mixture existing in the mold was pressed under atmospheric pressure. After that, the fins that have been temporarily formed are removed from the mold, and are not pressurized. A square vacuum thermostatic dryer (trade name DP300) manufactured by Yamato Scientific is used to heat at a pressure of 0.1 KPa or less and a temperature of 150 ° C. The heat sink was made in 15 hours. At this time, the temperature rise rate in the mold from 23 ° C to 150 ° C was about 0.5 ° C / min, and it took about 30 minutes to pass through the temperature range of the liquid crystal state of the compound (1) manufactured by JNC Corporation. . Finally, it reached 150 ° C, and polymerization was performed while maintaining the temperature.

<Example 7> For boron nitride, Platelets 003 manufactured by Japan 3M Co., Ltd. was used instead of PTX-25, and 0.033 g of a mixture of Plateltes and PT were measured respectively. A heat sink was produced in the same manner as in Example 1 except that 0.930 g of the -670 mixture was sufficiently mixed. Platelets 003 and PT-670 with different particle sizes determine the mixing ratio and content in such a way that the space ratio between the particles is the smallest (in order to become the most densely packed).

<Evaluation of Thermal Conductivity> The specific thermal conductivity of the heat sink is determined in advance (measured with a high-sensitivity differential scanning calorimeter Thermo Plus EVO2 DSC-8231 manufactured by Rigaku) and specific gravity (produced by Shin Optoelectronics) (Measured by DME-220, a specific electronic balance type hydrometer), and multiplying this value by the thermal diffusivity obtained by an LFA467 thermal diffusivity measuring device manufactured by NETZSCH Japan (Stock), thereby calculating The thermal conductivity in the thickness direction. <Evaluation of thermal expansion coefficient> A 4 mm × 20 mm test piece was cut out of the obtained sample, and the thermal expansion coefficient was determined in a range of 50 ° C. to 200 ° C. (determined using a TMA-SS6100 thermomechanical analysis device of SII (stock) ). The length of the test piece is appropriately prepared according to the shape of the sample to be measured. The measurement results are shown in FIGS. 5 to 8.

Regarding the heat sinks of Examples 1 to 7, Table 1 shows the thermal conductivity in the thickness direction, the thickness, and the linear expansion coefficient (TMA). [Table 1]

As described above, the thermal conductivity in the thickness direction of the heat sink of the present invention is improved. Furthermore, the linear expansion coefficient measured using thermomechanical analysis (TMA) shows the linear expansion coefficient (Si: 2.4 ppm / K, GaN: 4.0 ppm / K, SiC: 4.3 ppm / K) of the previous semiconductor substrate and The median value of copper is 16.8 ppm / K. Therefore, it is considered that when the heat sink of the present invention is used as a semiconductor substrate, a decrease in reliability due to a difference in linear expansion coefficient can be suppressed.

For the publications cited in this specification, and all documents including Japanese patent applications and Japanese patents, each document is specifically indicated and incorporated into the present case by reference, and its entire contents are the same as described in the present case This case is incorporated by reference.

The use of nouns and the same designations used in connection with the description of the present invention (especially in connection with the scope of patent applications below), as long as it is not specifically pointed out in this specification or is not clearly contradictory to the context, can be understood as involving the singular and Plural. The words "including", "having", "containing", and "including" can be understood as open end terms (ie, "including ~ but not limited to") unless otherwise specified. The detailed description of the numerical range in this specification is only intended to play a role as a notation to describe each value within the range as long as it is not specifically stated in the specification, such as listing each value in this specification one by one Generally incorporated into the manual. All the methods described in this specification can be performed in all appropriate order as long as they are not specifically pointed out in this specification or are not clearly contradictory to context. All examples or illustrative words (such as "etc.") used in this specification are only intended to better illustrate the present invention, and are not intended to limit the scope of the present invention, unless otherwise specifically claimed. Any wording in the specification should not be interpreted to mean an element that is not described in the scope of a patent application that is indispensable for implementing the present invention.

In this specification, in order to implement the present invention, a preferred embodiment of the present invention will be described including the best form known to the inventors. For those skilled in the art, after reading the description, modifications of the preferred embodiments will be clear. The present inventor anticipates that a skilled person may suitably apply such a modification, and plans to implement the present invention by methods other than those specifically described in this specification. Therefore, as permitted by the benchmark method, the present invention includes all changes and equivalents described in the scope of patent application accompanying this specification. Furthermore, as long as it is not specifically pointed out in the present specification or is not clearly contradictory to the context, any combination of the elements in all the modifications is included in the present invention.

1‧‧‧ stainless steel plate

2‧‧‧ aluminum plate

3‧‧‧ Bolt

FIG. 1 is a view showing an image when a secondary particle of boron nitride is used as an inorganic filler. FIG. 2 is an image diagram showing a heat sink of the present invention. FIG. 3 shows an unmodified filler (left), a filler treated with a silane coupling agent (center), an inorganic filler contained in a composition used in the present invention, and a surface modification with a polymerizable compound after the treatment with a silane coupling agent. Image of the filler (right). FIG. 4 is a schematic diagram of a device for applying pressure to a composition in an example. 5 is a graph (9 ppm / K) showing an average linear expansion coefficient from 50 ° C. to 200 ° C. in the TMA of Example 1. FIG. FIG. 6 is a graph (7 ppm / K) showing the average linear expansion coefficient from 50 ° C to 200 ° C in the TMA of Example 3. FIG. FIG. 7 is a graph (7 ppm / K) showing the average linear expansion coefficient from 50 ° C. to 200 ° C. in the TMA of Example 4. FIG. FIG. 8 is a graph (10 ppm / K) showing the average linear expansion coefficient from 50 ° C. to 200 ° C. in the TMA of Example 5. FIG.

Claims (17)

A method for manufacturing a heat sink is a method for manufacturing a heat sink, and the method for manufacturing a heat sink includes a calcining step, wherein the calcining step includes curing an inorganic filler, a polymerizable compound, and the polymerizable compound. The composition of the hardener is heated in such a manner as to apply pressure from a direction that becomes the vertical direction with respect to the thickness of the heat sink, and polymerizes the polymerizable compound. The method for manufacturing a heat sink according to item 1 of the scope of patent application, further comprising a vacuum step, in which the polymerizable compound penetrates into the filler or the gap between the fillers before the calcination step. In the method, pressure is applied to the composition from a direction that becomes the up-down direction, and the composition is placed in a vacuum environment, and the calcination step is performed under the vacuum environment to the composition from the up-down direction. Apply pressure and heat in the direction of. The method for manufacturing a heat sink according to item 2 of the scope of patent application, further comprising a temporary forming step. The temporary forming step is before the vacuum step, and the composition is turned into the vertical direction at atmospheric pressure. A pressure is applied in a direction of 50 ° C., and the polymerizable compound is heated at a temperature lower than a polymerization temperature so as to be compression-molded. A method for manufacturing a heat sink, which is a method for manufacturing a heat sink. The method for manufacturing a heat sink includes: a temporary forming step, including an inorganic filler, a polymerizable compound, and a polymerizable compound under atmospheric pressure or a vacuum environment. The composition of the hardened hardener is applied with pressure from a direction that is up and down with respect to the thickness of the heat sink, and is heated below the polymerization temperature by compression-molding the polymerizable compound; a vacuum step is performed at After the temporary forming step, in order to make the polymerizable compound penetrate into the filler or the gap between the fillers, the composition is placed in a vacuum environment; and a calcination step is performed on the composition in a vacuum environment. Heating is performed so as to polymerize the polymerizable compound. The method for manufacturing a heat sink according to any one of claims 1 to 4, wherein the inorganic filler comprises a first inorganic filler and a second inorganic filler having a particle size smaller than the first inorganic filler. A mixing ratio of the first inorganic filler and the second inorganic filler is a ratio in which a filling ratio when a space ratio between fillers is minimum is set to 100%, and the filling ratio becomes 70% or more, the first inorganic filler The filler is secondary particles obtained by aggregating acicular or plate-like particles. The method for manufacturing a heat sink according to any one of claims 1 to 4, wherein the inorganic filler is formed of a nitride, and the polymerizable compound has oxetanyl groups at both ends. In the polymerizable liquid crystal compound having an oxetanyl group or an oxetanyl group, the heating temperature in the firing step is at least the temperature range in which the polymerizable liquid crystal compound exhibits a liquid crystal phase. The method for manufacturing a heat sink according to item 6 of the patent application scope, comprising the steps of: in the liquid crystal phase of the polymerizable liquid crystal compound, when the temperature of the temporary forming step or the calcining step is elevated. It stays in the display temperature region for more than 1 second or stays for more than 1 second. The method for manufacturing a heat sink according to item 6 of the patent application, further comprising an alignment processing step, wherein the alignment processing step is performed before the temporary forming step and the calcining step. The method for manufacturing a heat sink according to item 6 of the application, wherein the polymerizable liquid crystal compound is at least one compound represented by the following formula (1-1), R ^a1 -Z- (AZ) _m1 -R ^a1 ･ ･ ･ (1-1) In the formula (1-1), R ^a1 is a polymerizable group represented by any one of the following formulae (2-1) to (2-2); A 1,4-cyclohexyl, 1,4-cyclohexenyl, 1,4-phenylene, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene-2 , 7-diyl, bicyclic [2.2.2] octane-1,4-diyl, or bicyclic [3.1.0] hex-3,6-diyl, among these rings, any -CH ₂ -may Substituted by -O-, any -CH = may be substituted by -N =, any hydrogen may be substituted by halogen, alkyl group having 1 to 10 carbon atoms, or halogenated alkyl group having 1 to 10 carbon atoms. In the group, any -CH ₂ -may be substituted by -O-, -CO-, -COO-, or -OCO-, and any -CH ₂ CH ₂ -may be -CH = CH-, or -C≡C. -Substitution; Z is a single bond or an alkylene group having 1 to 20 carbon atoms, in the alkylene group, any -CH ₂ -may be passed through -O-, -S-, -CO-, -COO -, Or -OCO- substitution, any -CH ₂ CH ₂ -can be via -CH = CH-, -CF = CF-, -CH = N-, -N = CH-, -N = N-, or -C≡C- substitution, any hydrogen may be substituted by halogen; m1 is an integer from 1 to 6, In the formulae (2-1) to (2-2), R ^b is hydrogen, halogen, -CF ₃ , or an alkyl group having 1 to 5 carbon atoms, and q is 0 or 1. The method for manufacturing a heat sink according to item 9 of the scope of patent application, wherein in the formula (1-1), A is 1,4-cyclohexyl, and any hydrogen is substituted with a 1,4-cyclo ring Hexyl, 1,4-phenylene, 1,4-phenylene with any hydrogen substituted with halogen or methyl, fluorene-2,7-diyl with any hydrogen substituted with halogen or methyl 2,7-diyl. The method for manufacturing a heat sink according to item 10 of the scope of patent application, wherein in the formula (1-1), Z is a single bond,-(CH ₂ ) _a- , -O (CH ₂ ) _a -,- (CH ₂ ) _a O-, -O (CH ₂ ) _a O-, -CH = CH-, -C≡C-, -COO-, -OCO-, -CH = CH-COO-, -OCO-CH = CH-, -CH ₂ CH ₂ -COO-, -OCO-CH ₂ CH _2- , -CH = N-, -N = CH-, -N = N-, -OCF _2- , or -CF ₂ O -, Said a is an integer of 1-20. The method for manufacturing a heat sink according to any one of claims 1 to 4, wherein the inorganic filler is at least one selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride. The method for manufacturing a heat sink according to any one of claims 1 to 4, wherein the hardener is at least one diamine compound represented by the following formula (3-1), H ₂ NZ -(AZ) _m2 -NH ₂ ･ ･ ･ (3-1) In the formula (3-1), A is 1,4-cyclohexyl, or 1,4-phenylene. Any of these rings Hydrogen may be substituted by halogen or an alkyl group having 1 to 10 carbon atoms; Z is a single bond or an alkylene group having 1 to 10 carbon atoms; m2 is an integer of 1 to 7; The method for manufacturing a heat sink according to any one of claims 1 to 4, wherein the inorganic filler is a filler treated with a silane coupling agent, or the polymerizable polymer is treated by the silane coupling agent. Compounds are surface-modified fillers. A heat sink is formed of a composition comprising: a polymerizable liquid crystal compound having a structure containing an oxetanyl group or an oxetanyl group at both ends; a hardening agent for the polymerizable liquid crystal Compound hardening; and an inorganic filler formed of a nitride, and in the heat sink, the inorganic filler includes a first inorganic filler, and a second inorganic filler having a particle size smaller than the first inorganic filler, the first inorganic filler The mixing ratio of the filler and the second inorganic filler is a ratio in which the filling ratio becomes 70% or more when the filling ratio when the space ratio between the fillers is the smallest is 100%, and the first inorganic filler is a needle or a plate Secondary particles formed by agglomerating particles, the thickness of the heat sink is 200 μm to 1000 μm, and the thermal conductivity in the thickness direction of the heat sink exceeds 20 W / mK. A substrate includes: the heat sink according to item 15 of the scope of patent application; and a metal plate laminated on at least one side of the heat sink. A power semiconductor module includes: a substrate for a power semiconductor, which has a heat sink as an insulating substrate as described in item 15 of the scope of patent application, and a conductor circuit formed on the heat sink; and a power semiconductor chip, configured The inorganic filler is boron nitride on the power semiconductor substrate and is electrically connected to the conductor circuit.