JP2013145841A - Application liquid for formation of interlayer packed bed layer of three-dimensional integrated circuit and three-dimensional integrated circuit manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an application liquid for formation of an interlayer packed bed of a three-dimensional integrated circuit, which can form, at a time of a B-stage heat treatment, a homogenous B-stage film from a coated film formed on a semiconductor substrate by evaporating and removing an organic solvent at a moderate evaporation rate by application; and which can form a favorable interlayer packed bed layer by heat hardening the B-stage film.SOLUTION: An application liquid for formation of an interlayer packed bed layer of a three-dimensional integrated circuit, includes: a thermosetting resin (A) which has a heat transfer coefficient of 0.2 W/mK and over, melt viscosity at 50°C of 500 Pa s and over, and melt viscosity at 120°C of 100 Pa s and under; an inorganic filler (B) which has a heat transfer coefficient of 2 W/mK and over, an average grain size of not less than 0.1 μm and not more than 5 μm, and a maximum grain size of 10 μm and under; a surface-active agent (D); and an organic solvent (E) which has a boiling point of 120°C and over.

Description

  The present invention relates to a coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit and a method for manufacturing a three-dimensional integrated circuit using the coating liquid.

  In recent years, in order to further improve the performance of semiconductor devices such as higher speed and higher capacity, in addition to miniaturization of transistors and wiring, three-dimensional (3D) stacking by stacking two or more semiconductor device chips Research and development of integrated circuits is underway.

  A three-dimensional integrated circuit has a structure in which semiconductor device chips are connected to each other by electrical signal terminals such as solder bumps between the chips, and at the same time, are bonded by an interlayer filling layer formed by filling an interlayer filler. have.

  Specifically, after a thin film is formed by applying a coating solution for forming an interlayer filling layer on a wafer, heating is performed to form a B stage, and then chips are cut out by dicing. There has been proposed a process of stacking, repeating temporary bonding by pressure heating, and finally performing main bonding (solder bonding) under pressure heating conditions (for example, see Non-Patent Document 1).

  Various problems have been pointed out for the practical application of such a three-dimensional integrated circuit device. One of them is a problem of heat dissipation from heat generated from devices such as transistors and wiring. This problem is generally caused by the fact that the thermal conductivity of the interlayer filling layer forming composition used for stacking semiconductor device chips is very low compared to metals, ceramics, etc. There is concern about performance degradation due to heat storage.

  One technique for solving this problem is to increase the thermal conductivity of the interlayer filling layer forming composition. Specifically, a high thermal conductivity epoxy resin is used as the thermosetting resin constituting the adhesive component of the interlayer filling layer forming composition, or such a high thermal conductivity resin and a high thermal conductivity inorganic filler are combined. The composition for forming an interlayer filling layer is made to have a high thermal conductivity. For example, Patent Document 1 describes a composition for forming an interlayer filling layer in which a spherical boron nitride aggregate is blended as a filler.

In addition to the improvement of thermal conductivity, the composition for forming an interlayer filling layer is required to have compatibility with a 3D lamination process, a thin film, and also a bonding property of electrical signal terminals between semiconductor device chips. Therefore, further technological development is needed.
That is, in the conventional process of mounting a semiconductor device chip on an interposer or the like, first, an electrical signal terminal such as a solder bump on the semiconductor device chip side is activated by flux, and then a substrate having lands (electric junction electrodes) is formed. After joining, joining is performed by filling and hardening the liquid resin or the underfill material which added the inorganic filler to the liquid resin between the board | substrates. Here, the flux is required to have an activation processing function such as removal of surface oxide film of the metal electric signal terminals such as solder bumps and land, improvement of wettability, and prevention of reoxidation of the surface of the metal terminal.
On the other hand, in the 3D stacking process of the semiconductor device chip, when the activation process of the electrical signal terminals such as solder bumps using the flux is first performed, a flux layer having low thermal conductivity is formed on the surface of the terminal, and the interlayer filling layer There is a concern that the formation composition may hinder the thermal conductivity between the laminated substrates and cause corrosion deterioration of the junction terminal due to the residual flux component.
For this reason, the flux which can be directly mixed with the composition for interlayer filling layer formation which has high heat conductivity, and has low corrosiveness to a metal terminal is calculated | required.

  Conventionally, as such a flux, in addition to an inorganic metal salt containing a halogen having excellent ability to dissolve a metal oxide film of an electric signal terminal, an organic acid, an organic acid salt, an organic halogen compound, an amine, rosin and its constituent components Are used alone or in combination (see, for example, Non-Patent Document 2).

  As described above, the conventional interlayer filling layer forming composition generally includes a thermosetting resin as an adhesive component, an inorganic filler, and a flux, but this interlayer filling layer forming composition is usually suitable. It is applied to a semiconductor substrate as a coating liquid which is dispersed or dissolved in an organic solvent and adjusted to an appropriate viscosity.

Japanese translation of PCT publication No. 2008-510878

Proceedings of the Japan Institute of Electronics Packaging, 61, 23, 2009) Basics and application of soldering (Industry Research Committee)

  After applying the coating liquid for the composition for forming the interlayer filling layer of the three-dimensional integrated circuit to the substrate surface, it is heated to form a B-stage, and further, provisional bonding and main bonding are performed to manufacture the three-dimensional integrated circuit. The organic solvent used for the preparation needs to be removed by evaporation at an appropriate evaporation rate during the heat treatment for B-stage formation. That is, when the evaporation rate of the organic solvent is too slow and cannot be efficiently removed by evaporation, the organic solvent may remain in the resulting B-staged film. It will evaporate at the time of high-temperature heating of the subsequent temporary bonding to the main bonding, and the evaporation trace of the organic solvent becomes a void and becomes a factor that hinders heat conduction between the laminated substrates. On the other hand, if the evaporation rate of the organic solvent at the time of B-stage formation is excessively high, the resulting B-stage film will be roughened by evaporation of the organic solvent, and a homogeneous B-stage film can be obtained. Can not. If the film quality of the B-staged film is inhomogeneous, the interlayer filling layer formed by further heating this from the subsequent temporary bonding to the main bonding process also becomes inhomogeneous, and the air layer is involved due to surface roughness. This causes problems such as the formation of voids due to the above, a decrease in thermal conductivity between laminated substrates, and a decrease in adhesion.

  The present invention is a coating solution for forming an interlayer filling layer capable of forming an interlayer filling layer having high thermal conductivity, and from a coating film formed by coating on a semiconductor substrate, during a heat treatment for B-stage formation, It is possible to form a homogeneous B-staged film by evaporating and removing the organic solvent at an appropriate evaporation rate. Accordingly, the B-staged film can be cured by heating to form a good interlayer filling layer. It is an object of the present invention to provide a coating liquid for forming an interlayer filling layer of an original integrated circuit and a method for manufacturing a three-dimensional integrated circuit using the coating liquid.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention formed an interlayer filling layer in which a highly heat-conductive inorganic filler and a thermosetting resin having a high heat conductivity and an appropriate melt viscosity were combined. It has been found that by using an organic solvent having a predetermined boiling point as the organic solvent of the coating liquid for the composition for use, the evaporation of the organic solvent in the B-stage can be prevented.

  The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] A thermosetting resin (A) having a thermal conductivity of 0.2 W / mK or more, a melt viscosity at 50 ° C of 500 Pa · s or more, and a melt viscosity at 120 ° C of 100 Pa · s or less, and heat An inorganic filler (B) having a conductivity of 2 W / mK or more, an average particle size of 0.1 μm to 5 μm, and a maximum particle size of 10 μm or less, a surface activator (D), and a boiling point of 120 A coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit, comprising an organic solvent (E) at a temperature of at least ° C.

[2] The coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit according to [1], wherein the boiling point of the organic solvent (E) is 130 ° C. or higher and lower than 180 ° C.

[3] The coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit according to [1] or [2], further containing an organic solvent (F) having a boiling point of 60 ° C. or higher and lower than 120 ° C.

[4] Any one of [1] to [3], containing 5% by volume to 60% by volume of the inorganic filler (B) with respect to the total volume of the thermosetting resin (A) and the inorganic filler (B). A coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit according to the above.

[5] The coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit according to any one of [1] to [4], wherein the inorganic filler (B) is a boron nitride filler.

[6] The coating solution for forming an interlayer filling layer for a three-dimensional integrated circuit according to any one of [1] to [5], further containing a curing agent (C).

[7] The coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit according to [6], wherein the curing agent (C) is at least one selected from imidazole, imidazole derivatives, and dicyandiamine compounds.

[8] The interlayer filling layer of the three-dimensional integrated circuit according to any one of [1] to [7], wherein the surface activator (D) is at least one selected from organic carboxylic acids and organic carboxylic acid derivatives. Coating liquid for forming.

[9] A coating process in which a coating film is formed by coating the surface of a semiconductor substrate with the coating liquid according to any one of [1] to [8], and the semiconductor substrate on which the coating film is formed is combined with another semiconductor substrate. A method for manufacturing a three-dimensional integrated circuit, comprising a bonding step of laminating and pressing.

[10] The method for manufacturing a three-dimensional integrated circuit according to [9], further including a drying step of drying the coating film between the coating step and the bonding step.

[11] The method according to [9] or [10], wherein in the coating step, the coating liquid is applied to the surface of the semiconductor substrate by at least one coating device selected from a spin coater, a slit coater, a die coater, and a blade coater. A method of manufacturing a three-dimensional integrated circuit.

[12] The method for manufacturing a three-dimensional integrated circuit according to any one of [9] to [11], wherein the bonding step includes a heating step of heating to 200 ° C. or higher.

According to the coating liquid for forming the interlayer filling layer of the three-dimensional integrated circuit of the present invention, a highly thermally conductive interlayer filling layer can be formed. In addition, the organic solvent is evaporated and removed at an appropriate evaporation rate from the coating film formed by applying the coating liquid for forming the interlayer filling layer of the present invention on the semiconductor substrate at the time of the B-stage heat treatment. It is possible to form a uniform B-stage film without any disturbance in the film quality due to the evaporation roughening. That is, since the organic solvent contained in the coating liquid of the present invention has a relatively high boiling point of 120 ° C. or higher, it evaporates at an appropriate evaporation rate during the B-stage heat treatment, and therefore, due to evaporation roughening. It is possible to prevent the film quality from being disturbed.
Therefore, since this B-staged film can be cured by heating to form a good interlayer filling layer, a high-quality three-dimensional integrated circuit can be realized.

  Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Coating solution for forming interlayer filling layer of 3D integrated circuit]
The coating solution for forming the interlayer filling layer of the three-dimensional integrated circuit of the present invention is used to bond the semiconductor substrates constituting each layer of the three-dimensional integrated circuit to form an interlayer filling layer that fills the gap between the semiconductor substrates. A coating solution,
A thermosetting resin (A) having a thermal conductivity of 0.2 W / mK or more, a melt viscosity at 50 ° C. of 500 Pa · s or more, and a melt viscosity at 120 ° C. of 100 Pa · s or less,
An inorganic filler (B) having a thermal conductivity of 2 W / mK or more, an average particle size of 0.1 μm to 5 μm, and a maximum particle size of 10 μm or less, a surface activator (D), and a boiling point of 120 It is characterized by containing an organic solvent (E) at a temperature of not lower than ° C., and this interlayer filling layer forming coating solution preferably further contains a curing agent (C) and has a boiling point of 60 ° C. or higher and 120 ° C. You may contain the organic solvent (F) below [degreeC].
In the present invention, the “average particle size” of the inorganic filler (B) is measured by the method described in the Examples section below using a particle size distribution measuring device “SALD-2200” manufactured by Shimadzu Corporation. Indicates the value.

  Hereinafter, each component will be described.

[Thermosetting resin (A)]
In order to obtain high thermal conductivity by combining with the inorganic filler (B) as an interlayer filler, the thermal conductivity of the thermosetting resin (A) of the coating liquid for forming an interlayer filler of the present invention is 0.2 W / It must be mK or more, and is preferably 0.22 W / mK or more.

  In the present invention, the thermal conductivity of the thermosetting resin (A) is, among the components constituting the interlayer filling layer forming coating liquid of the present invention, as described in the Examples section below. When a curable resin (A), an organic solvent, and a curing agent (C) are further included in the coating solution, a cured film is formed according to a normal curing method using only the curing agent (C). Is a value obtained by the method described later.

  In addition, the thermosetting resin (A) has a melt viscosity of 500 Pa at 50 ° C. in order to perform alignment with the substrate to be bonded after forming a thin film on the substrate as a coating solution for forming an interlayer filling layer and before temporary bonding. It is essential that it is s or more, and this melt viscosity is preferably 1000 Pa · s or more. That is, when the melt viscosity at 50 ° C. of the thermosetting resin (A) is 500 Pa · s or more, the tack property at room temperature after the B-stage is reduced, and the alignment at the time of stacking the substrates is performed. In addition, it is possible to temporarily join the laminated substrates of the three-dimensional integrated circuit.

Further, when the main bonding is performed after the temporary bonding, the thermosetting resin (A) has a melt viscosity at 120 ° C. of 100 Pa · s or less in order to melt the resin by heating and connect the electric bonding terminals. It is essential that the melt viscosity is 20 Pa · s or less. That is, when the melt viscosity of the thermosetting resin (A) is 100 Pa · s or less at 120 ° C., the resin is melted before the solder bump is melted to greatly reduce the viscosity. Can be temporarily bonded to the land terminal, and further, the filler film formed on the semiconductor substrate is pressure-bonded at 200 ° C. or more to melt the solder bump and realize electrical connection with the land terminal. it can.
At this time, by adding a curing agent (C) described later, it does not harden at the B-stage or at the solder bump bonding temperature, and gels after having a short fluidity after the solder bump bonding. Then, it is preferable because a stable interlayer filling layer can be formed by complete curing thereafter.

  As the thermosetting resin (A), any thermosetting resin that satisfies the above thermal conductivity and melt viscosity conditions can be used.

Examples of the thermosetting resin (A) according to the present invention include polyimide resins such as polyimide resins, polyaminobismaleimide (polybismaleimide) resins, bismaleimide / triazine resins, polyamideimide resins, and polyetherimide resins; Examples include benzoxazole resins; polyether resins; benzocyclobutene resins; silicone resins; epoxy resins such as phenolic epoxy resins and alcoholic epoxy resins. Moreover, precursors, such as a corresponding monomer, dimer, oligomer, etc. which become the raw material of these resins may be used.
Among them, an epoxy resin, a polyether resin, a benzocyclobutene resin, and a silicone resin are preferable because of high thermal conductivity and good solubility in an organic solvent, and an epoxy resin is particularly preferable.
One of these thermosetting resins may be used alone, or two or more thereof may be used in any combination and ratio.

<Epoxy resin>
Hereinafter, an epoxy resin (hereinafter sometimes referred to as “epoxy resin (a)”) suitable as the thermosetting resin (A) will be described.

  The epoxy resin (a) may be only an epoxy resin having one type of structural unit, but a plurality of epoxy resins having different structural units may be combined as long as the melt viscosity condition is satisfied.

  In order to obtain a highly heat-conductive cured film by reducing voids at the time of joining in combination with coating properties or film-forming properties and adhesive properties, at least a phenoxy resin (hereinafter referred to as “epoxy resin”) as an epoxy resin (a). (A1) ”may be included).

  The phenoxy resin usually refers to a resin obtained by reacting an epihalohydrin with a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound with a divalent phenol compound. Among them, a phenoxy resin which is a high molecular weight epoxy resin having a weight average molecular weight of 2000 or more is particularly referred to as an epoxy resin (a1). Here, the weight average molecular weight means a value in terms of polystyrene by gel permeation chromatography. The same applies to the following.

  The epoxy resin (a1) is preferably a phenoxy resin having at least one skeleton selected from the group consisting of naphthalene skeleton, fluorene skeleton, biphenyl skeleton, anthracene skeleton, pyrene skeleton, xanthene skeleton, adamantane skeleton and dicyclopentadiene skeleton. . Among these, a phenoxy resin having a fluorene skeleton and / or a biphenyl skeleton is particularly preferable because heat resistance is further improved.

As described above, the epoxy resin (a) may include a plurality of epoxy resins having different structural units.
The epoxy resin other than the epoxy resin (a1) is preferably an epoxy resin having two or more epoxy groups in the molecule (hereinafter sometimes referred to as “epoxy resin (a2)”). Bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, triphenylmethane type epoxy resin, dicyclopentadiene Various epoxy resins, such as a type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, and a polyfunctional phenol type epoxy resin, can be mentioned.

  As the epoxy resin (a1) and the epoxy resin (a2), one type may be used alone, or two or more types may be used in any combination and ratio.

  The weight average molecular weight of the epoxy resin (a2) is preferably 100 to 2000, more preferably 200 to 1500, from the viewpoint of melt viscosity control. When the weight average molecular weight is less than 100, the heat resistance tends to be inferior. When it is more than 2000, the melting point of the epoxy resin tends to be high, and the workability tends to decrease.

  In addition, the epoxy resin (a) may contain an epoxy resin other than the epoxy resin (a1) and the epoxy resin (a2) (hereinafter referred to as “other epoxy resin”) as long as the purpose is not impaired. The content of the other epoxy resin is usually 50% by weight or less, preferably 30% by weight or less, based on the total of the epoxy resin (a1) and the epoxy resin (a2).

In the present invention, the proportion of the epoxy resin (a1) in the total epoxy resin (a) including the epoxy resin (a1) and the epoxy resin (a2) is preferably 5 to 95% by weight, with the total as 100% by weight. More preferably, it is 10-90 weight%, More preferably, it is 20-80 weight%. "Epoxy resin (a1) and all epoxy resin (a2) including epoxy resin (a2)" means that when epoxy resin (a) is only epoxy resin (a1) and epoxy resin (a2), It means the total of the epoxy resin (a1) and the epoxy resin (a2), and when it contains other epoxy resins, it means the total of the epoxy resin (a1), the epoxy resin (a2) and the other epoxy resins.
When the ratio of the epoxy resin (a1) in the epoxy resin (a) is not less than the above lower limit, the effect of improving the thermal conductivity by blending the epoxy resin (a1) can be sufficiently obtained, and the desired high heat Conductivity can be obtained. When the ratio of the epoxy resin (a1) in the epoxy resin (a) is not more than the above upper limit and the epoxy resin (a2) is particularly 10% by weight or more, the blending effect of the epoxy resin (a2) is exhibited, and the curability, The physical properties of the cured film will be sufficient.

[Filler]
<Inorganic filler (B)>
The inorganic filler (B) used in the present invention is an inorganic material having a thermal conductivity of 2 W / mK or more, preferably 3 W / mK or more, an average particle size of 0.1 to 5 μm, and a maximum particle size of 10 μm or less. Consists of.

  By including the inorganic filler (B) having high thermal conductivity, the coating liquid for forming the interlayer filling layer of the present invention can impart high thermal conductivity to the interlayer filling layer to be formed. The semiconductor device can be stably operated by promoting the heat conduction between them and lowering the temperature of the semiconductor device substrate to prevent heat storage.

  The inorganic filler (B) must have an average particle size of 0.1 to 5 μm and a maximum particle size of 10 μm or less, preferably an average particle size of 0.3 to 4.5 μm and a maximum particle size The diameter is 9.5 μm or less, more preferably the average particle size is 0.5 to 4 μm, and the maximum particle size is 9 μm or less.

  In the three-dimensional integrated circuit, the distance between chips has been reduced to a distance between chips of about 10 to 50 μm in order to improve performance such as higher speed and higher capacity. The maximum particle size of the filler to be blended is preferably about 1/3 or less of the thickness of the interlayer filling layer.

If the maximum particle size of the inorganic filler (B) exceeds 10 μm, the inorganic filler protrudes from the surface of the interlayer filling layer after curing, and the surface shape of the interlayer filling layer tends to deteriorate.
On the other hand, if the particle size of the inorganic filler (B) is too small, the number of necessary heat conduction paths increases and the probability of connection from the top to the bottom in the thickness direction between the chips decreases, and thermosetting with high thermal conductivity. Even in combination with the resin (A), the thermal conductivity in the thickness direction of the interlayer filling layer becomes insufficient. Moreover, when the particle size of an inorganic filler (B) is too small, an inorganic filler (B) will aggregate easily and the dispersibility in the coating liquid for interlayer filling layer formation will worsen. By setting the average particle size of the inorganic filler (B) in the above range, excessive aggregation of the fillers can be suppressed, and an interlayer filled layer having sufficient thermal conductivity in the thickness direction can be obtained.

  In the present invention, the average particle size and the maximum particle size of the inorganic filler (B) are described below for the inorganic filler (B) in the coating solution using a particle size distribution measuring device “SALD-2200” manufactured by Shimadzu Corporation. It is a value measured by the method described in the example section.

As for the inorganic material used as the inorganic filler (B), immediately after synthesis or after synthesis, the powder may aggregate and may not satisfy the above particle size range. Therefore, it is preferable to pulverize and use the inorganic material used as the inorganic filler (B) so as to satisfy the above particle size range.
The method for pulverizing the inorganic material is not particularly limited, and a conventionally known pulverization method such as a method of stirring and mixing with a pulverizing medium such as zirconia beads or jet injection can be applied.

  In addition, the inorganic filler (B) may be appropriately subjected to surface treatment in order to enhance dispersibility in the thermosetting resin (A) or the coating liquid.

Inorganic materials having a thermal conductivity of 2 W / mK or more as the inorganic filler (B) include alumina (Al ₂ O ₃ : thermal conductivity 30 W / mK), aluminum nitride (AlN: thermal conductivity 260 W / mK), nitriding Examples thereof include boron (BN: thermal conductivity 3 W / mK (thickness direction), 275 W / mK (in-plane direction)), silicon nitride (Si ₃ N ₄ : thermal conductivity 23 W / mK), and the like.

In addition to high thermal conductivity, the inorganic filler (B) preferably has both stability against high-temperature exposure to oxygen and water and low dielectric properties from the viewpoint of the reliability of the bonded device. Therefore, among the inorganic materials, as the inorganic filler (B), Al ₂ O ₃ and BN having high chemical stability are preferable, and BN having a lower dielectric constant is particularly preferable.

  In addition, an inorganic filler (B) may be used individually by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

Moreover, you may use 2 or more types of fillers from which an average particle diameter differs as an inorganic filler (B). For example, an inorganic filler having a relatively small average particle diameter, for example, 0.1 to 2 μm, preferably 0.2 to 1.5 μm, and a relatively large average particle diameter, for example, 1 to 5 μm, preferably 1 to 3 μm. By using a filler in combination, the heat conduction path between inorganic fillers with a large average particle diameter is connected with an inorganic filler with a small average particle diameter, so that a high filling can be achieved compared to the case of using only those with the same average particle diameter. It becomes possible, and higher thermal conductivity can be obtained.
In this case, the inorganic filler having a small average particle diameter and the inorganic filler having a large average particle diameter are preferably used in a weight ratio of 10: 1 to 1:10 in terms of forming a heat conduction path.

<Other fillers (B ')>
Furthermore, the coating liquid for forming an interlayer filling layer of the present invention is a filler other than the inorganic filler (B) (hereinafter, “other filler (B ′)” within the range that does not impair the effects of the present invention for the purpose of viscosity adjustment and the like. 1 type) or 2 or more types.
For example, when a filler is added for the purpose of adjusting viscosity rather than improving thermal conductivity, silica (SiO ₂ : thermal conductivity 1.4 W / mK), which is not so high in thermal conductivity, is used. be able to.
However, the average particle size and maximum particle size of the other filler (B ′) need to be in the same range as the inorganic filler (B).

<Content>
In the present invention, the content of the inorganic filler (B) is 5% by volume or more and 60% by volume or less, particularly 10% with respect to the total volume (total volume) of the thermosetting resin (A) and the inorganic filler (B). It is preferable to make it -55 volume%, especially 15-50 volume%. By setting it as such content, the coating liquid for interlayer filling layer formation of this invention can maintain sufficient viscosity that a sufficient heat conductivity is obtained, and a uniform coating film can be formed.
If the content of the inorganic filler (D) is less than the above lower limit, sufficient thermal conductivity may not be obtained in the formed interlayer filling layer, and if the upper limit is exceeded, the viscosity of the coating liquid increases. Problems such as inability to form a uniform coating may occur.

  In addition, when using said other filler (B ') together, it is preferable that content of the sum total of an inorganic filler (B) and another filler (B') shall be below the said minimum, and an inorganic filler (B ), The other filler (B ′) is 50% by volume or less, particularly 40% by volume with respect to the total filler which is the sum of the inorganic filler (B). % Or less, for example, 5 to 40% by volume is preferable.

[Surfactant (D)]
Specifically, the surface activator (D) is a method of dissolving and removing a metal electric signal terminal such as a solder bump and a surface oxide film on a land, or spreading a solder bump on the land surface of a solder bump when soldering a metal terminal. The compound which has a flux function, such as the improvement of property, and also the reoxidation prevention of the metal terminal surface of a solder bump.
More specifically, it refers to the one that gives good results in the evaluation of the solder ball melting property in Experimental Example 2 described later.

  Surface activator (D) is a coating solution for forming an interlayer filling layer that is highly soluble in monomers, oligomers, polymers, and organic solvents of thermosetting resin (A) components such as epoxy resin (a), and is uniform by mixing. What can form is preferable. In addition, when the surface activator (D) acts as a curing agent on the thermosetting resin (A) component such as the epoxy resin (a), at a temperature before B-stage or solder bump bonding, Since the thermosetting resin fat is cured to inhibit the bonding of the solder bumps and the land to the land, those having no action as such a curing agent are preferable.

  As the surface activator (D) used in the present invention, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, malic acid, tartaric acid, citric acid, lactic acid, acetic acid, propionic acid, butyric acid, oleic acid, stearic acid Organic carboxylic acids such as benzoic acid, abietic acid and rosin; and organic carboxylic acid esters which are hemiacetal esters converted by reacting organic carboxylic acids with alkyl vinyl ethers; glutamic acid hydrochloride, aniline hydrochloride, hydrazine hydrochloride, Organohalogen compounds such as cetylpyridine bromide, phenylhydrazine hydrochloride, tetrachloronaphthalene, methylhydrazine hydrochloride, methylamine hydrochloride, ethylamine hydrochloride, diethylamine hydrochloride, butylamine hydrochloride; amines such as urea and diethylenetriamine hydrazine; Ethylene glycol Polyhydric alcohols such as diethylene glycol, triethylene glycol, tetraethylene glycol, glycerin; inorganic acids such as hydrochloric acid, hydrofluoric acid, phosphoric acid, borohydrofluoric acid; potassium fluoride, sodium fluoride, ammonium fluoride, fluoride Fluorides such as copper, nickel fluoride, zinc fluoride; chlorides such as potassium chloride, sodium chloride, cuprous chloride, nickel chloride, ammonium chloride, zinc chloride, stannous chloride; potassium bromide, sodium bromide And bromides such as ammonium bromide, tin bromide and zinc bromide. These compounds may be used as they are or may be microencapsulated using a coating agent made of an organic polymer or an inorganic compound. These compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them in arbitrary combinations and ratios.

  Of these, organic carboxylic acid derivatives such as organic carboxylic acids and carboxylic acid esters are preferred because of their solubility in thermosetting resins (A) such as epoxy resins (a) and various organic solvents. Further, organic carboxylic acid esters are particularly preferred from the viewpoint of low curing acceleration ability at room temperature with respect to thermosetting resins (A) such as epoxy resins (a) and the storage stability of the coating solution for forming an interlayer filling layer.

  The organic carboxylic acid ester can be obtained by heating the organic carboxylic acid and the alkyl vinyl ether according to the following formula (I) at normal temperature, normal pressure, or if necessary. Since the reaction of formula (I) is also an equilibrium reaction, in order to increase the proportion of the organic carboxylic acid converted to the organic carboxylic acid ester, an equal amount or more of an alkyl vinyl ether is added to the carboxyl group in the organic carboxylic acid. It is preferable to make it react.

(In the formula (I), R ₁ represents the remaining molecular chain excluding one carboxyl group in the carboxylic acid. R ₂ represents an alkyl group having 1 to 6 carbon atoms.)

  The organic carboxylic acid ester is decomposed by heating in the coating solution for forming the interlayer filling layer to produce an organic carboxylic acid and vinyl ether. The organic carboxylic acid produced by the decomposition exhibits a surface activation action (flux action) on the solder balls.

  In addition, the organic carboxylic acid generated by the decomposition may exhibit a curing action on the thermosetting resin (A) such as the epoxy resin (a). This is because, for example, hydrogen ions released by dissociation of the carboxyl group may exhibit a curing action on the epoxy resin. In order to suppress the generation of hydrogen ions due to the dissociation of the carboxyl group, an organic carboxylic acid ester obtained by protecting an organic carboxylic acid with an alkyl vinyl ether is preferably used.

On the other hand, when the organic carboxylic acid ester is used, if the decomposition temperature is too low, the thermosetting resin (A) such as the epoxy resin (a) is cured at the time of temporary bonding by pressure heating at the time of manufacture. There is a risk that.
Therefore, the decomposition temperature of the organic carboxylic acid ester as the surface activator (D) is preferably 130 ° C. or more, more preferably 140 ° C. in order to avoid or suppress decomposition at the time of temporary bonding. Preferably it is 160 degreeC or more, Most preferably, it is 180 degreeC or more.

  Organic carboxylic acids used as raw materials for organic carboxylic acid esters include monocarboxylic acids such as lactic acid, acetic acid, propionic acid, butyric acid, oleic acid, stearic acid, benzoic acid, abietic acid, and rosin; succinic acid, malonic acid, succinic acid, Dicarboxylic acids such as glutaric acid, adipic acid, malic acid, tartaric acid, isophthalic acid, pyromellitic acid, maleic acid, fumaric acid, itaconic acid; citric acid, 1,2,4-trimellitic acid, tris (2-carboxyethyl) ) Tricarboxylic acids such as isocyanurate; tetracarboxylic acids such as pyromellitic acid and butanetetracarboxylic acid can be used. Among these, polycarboxylic acids having two or more carboxyl groups are preferable from the viewpoint of reactivity as a surface activator.

In addition, as alkyl vinyl ethers used as raw materials for organic carboxylic acid esters, R ₂ in the above formula (I) is preferably an alkyl group having 1 to 6 carbon atoms, among which R ₂ is a methyl group, an ethyl group, a propyl group. Group is preferably a butyl group. Among these alkyl groups, the lower the electron donating property, the higher the temperature dissociation property, so the alkyl group is preferably secondary or primary.

  As organic carboxylic acid esters, commercially available products such as Santacid G (dialkyl vinyl ether block bifunctional polymer carboxylic acid), Santacid H (monoalkyl vinyl ether block bifunctional low molecular weight carboxylic acid) manufactured by NOF Corporation, Santacid I ( Monoalkyl vinyl ether block bifunctional carboxylic acid) and the like can be preferably used.

  In the interlayer filling layer forming coating solution of the present invention, the content of the surface activator (D) is 0.1 to 10 parts by weight, preferably 0, per 100 parts by weight of the thermosetting resin (A). .5 parts by weight or more and 5 parts by weight or less. If the content of the surface activator (D) is less than the lower limit, there is a risk of poor solder connection due to a decrease in oxide film removability, and if it exceeds the upper limit, there is a risk of poor connection due to an increase in the viscosity of the coating solution. .

[Organic solvent]
As the organic solvent of the coating solution for forming the interlayer filling layer of the present invention, the solid content of the coating solution for forming the interlayer filling layer (components other than the organic solvent of the coating solution for forming the interlayer filling layer) can be uniformly dissolved or dispersed. Can be used as long as it satisfies the boiling point condition of the organic solvent of the present invention, and is not particularly limited. For example, alcohol solvents, aromatic solvents, amide solvents, alkane solvents, ethylene glycol ethers exemplified below And those having a suitable boiling point can be selected from ether / ester solvents, propylene glycol ether and ether / ester solvents, ketone solvents, and ester solvents.

(Alcohol solvent)
Methanol (boiling point 64.7 ° C), ethanol (boiling point 78.4 ° C), butanol (boiling point 117 ° C), iso-propyl alcohol (boiling point 82.4 ° C), n-propyl alcohol (boiling point 97.15 ° C), tert -Butanol (boiling point 82.4 ° C.), 1,4-butanediol (boiling point 230 ° C.) 2-ethylhexanol (boiling point 183 to 185 ° C.), etc.

(Aromatic solvent)
Toluene (boiling point 110.6 ° C), xylene (boiling point 144 ° C), etc.

(Amide solvent)
N, N-dimethylformamide (boiling point 153 ° C.), N, N-dimethylacetamide (boiling point 165 ° C.), etc.

(Alkane solvent)
n-hexane (boiling point 69 ° C.), iso-hexane (boiling point 68-70 ° C.), cyclohexane (boiling point 80.74 ° C.), methylcyclohexane (boiling point 101 ° C.), n-heptane (boiling point 98 ° C.), iso-octane ( Boiling point 99 ° C), n-decane (boiling point 174.2 ° C), etc.

(Ethylene glycol ether and ether / ester solvents)
Ethylene glycol monomethyl ether (boiling point 124 ° C), ethylene glycol ethyl ether (boiling point 135 ° C), ethylene glycol n-butyl ether (boiling point 171 ° C), ethylene glycol monoiso-butyl ether (boiling point 160 ° C), ethylene glycol hexyl ether (boiling point 208) ° C), ethylene glycol phenyl ether (boiling point 242 ° C), ethylene glycol monopropyl ether (boiling point 149.5 ° C), ethylene glycol monoiso-propyl ether (boiling point 141 ° C), diethylene glycol monomethyl ether (boiling point 194 ° C), diethylene glycol dimethyl ether (Boiling point 162 ° C), diethylene glycol monoethyl ether (boiling point 202 ° C), diethylene glycol diethyl ether (boiling point 189 ° C) Diethylene glycol n-butyl ether (boiling point 231 ° C.), diethylene glycol monoiso-butyl ether (boiling point 220 ° C.), diethylene glycol dibutyl ether (boiling point 256 ° C.), diethylene glycol hexyl ether (boiling point 259 ° C.), triethylene glycol monomethyl ether (boiling point 249 ° C.), Triethylene glycol monoethyl ether (boiling point 256 ° C.), triethylene glycol monobutyl ether (boiling point 271 ° C.), polyethylene glycol monomethyl ether (boiling point 295 ° C.), etc.

(Propylene glycol ether and ether / ester solvents)
Propylene glycol methyl ether (boiling point 120 ° C.), dipropylene glycol methyl ether (boiling point 190 ° C.), tripropylene glycol methyl ether (boiling point 242 ° C.), propylene glycol n-propyl ether (boiling point 150 ° C.), dipropylene glycol n-propyl Ether (bp 212 ° C.), tripropylene glycol n-propyl ether (bp 274 ° C.), propylene glycol n-butyl ether (bp 170 ° C.), propylene glycol-iso-butyl ether (bp 157 ° C.), dipropylene glycol n-butyl ether ( Boiling point 229 ° C.), tripropylene glycol n-butyl ether (boiling point 274 ° C.), propylene glycol phenyl ether (boiling point 243 ° C.), dipropylene glycol dimethyl ether Le (boiling point 175 ° C.), propylene glycol phenyl ether (boiling point 243 ° C.) such as

(Ketone solvent)
Acetone (boiling point 56 ° C.), methyl ethyl ketone (hereinafter abbreviated as “MEK”) (boiling point 80 ° C.), methyl propyl ketone (boiling point 102 ° C.), methyl n-butyl ketone (boiling point 128 ° C.), methyl iso-butyl ketone (hereinafter “ MIBK ") (boiling point 118 ° C), methyl iso-amyl ketone (boiling point 145 ° C), methyl n-amyl ketone (boiling point 152 ° C), ethyl butyl ketone (boiling point 149 ° C), ethyl sec-amyl ketone (boiling point 159 ° C). ), Acetylacetone (boiling point 140 ° C.), diacetone alcohol (boiling point 166 ° C.), diiso-butyl ketone (boiling point 169 ° C.), cyclohexanone (hereinafter abbreviated as “CHN”) (boiling point 157 ° C.), cyclohexylcyclohexanone (boiling point 261). ℃) etc.

(Ester solvent)
Methyl acetate (boiling point 57 ° C), ethyl acetate (boiling point 77 ° C), propyl acetate (boiling point 102 ° C), iso-propyl acetate (boiling point 88 ° C), butyl acetate (boiling point 126 ° C), iso-butyl acetate (boiling point 117 ° C) ), Sec-butyl acetate (boiling point 112 ° C.), amyl acetate (boiling point 146 ° C.), methyl amyl acetate (boiling point 146 ° C.), 2-ethylhexyl acetate (boiling point 199 ° C.), ethylene glycol ether methyl acetate (boiling point 145 ° C.), Ethylene glycol ether methyl acetate (boiling point 145 ° C), ethylene glycol ether ethyl acetate (boiling point 156 ° C), ethylene glycol ether n-butyl acetate (boiling point 188 ° C), diethylene glycol ether ethyl acetate (Boiling point 217 ° C), diethylene glycol ether n-butyl acetate (boiling point 245 ° C), ethylene glycol diacetate (boiling point 191 ° C), iso-butyl-iso-butyrate (boiling point 147 ° C), ethyl lactate (boiling point 154 ° C), butyl Lactate (boiling point 188 ° C.), 3-methyl-3-methoxybutyl acetate (boiling point 188 ° C.), ethyl lactate (boiling point 155 ° C.), propylene glycol monomethyl ether acetate (hereinafter abbreviated as “PGMEA”) (boiling point 146 ° C.) , Propylene glycol diacetate (boiling point 190 ° C.), propylene monomethyl ether methyl acetate (boiling point 188 ° C.), etc.

<Organic solvent (E)>
In the coating liquid for forming an interlayer filling layer of the present invention, by using an organic solvent (E) having a boiling point of 120 ° C. or higher, it is possible to prevent the evaporation roughening due to the rapid evaporation of the organic solvent during the B-stage and to form a homogeneous B A staged film can be formed. That is, as described later, the heating temperature in the heat treatment for B-stage formation is usually 50 to 150 ° C., preferably 70 to 120 ° C. Therefore, an organic solvent having a boiling point of 120 ° C. or higher can be used for this temperature condition. For example, it is removed by evaporation at an appropriate speed without causing evaporation. However, if the boiling point of the organic solvent (E) is excessively high, it is difficult to efficiently and highly evaporate and remove the organic solvent in the coating film during the heat treatment in the B-stage. ) Is preferably less than 180 ° C., more preferably 130 ° C. or more and less than 180 ° C., particularly preferably 140 to 170 ° C.

  As the organic solvent (E), among the above-mentioned various organic solvents, those having a boiling point of 120 ° C. or higher may be selected and used. In particular, the boiling point is in the above preferred range, and the solubility of the resin is high. Since it is favorable and the stability of the mixed solution is also good, it is preferable to use propylene glycol methyl ether, methyl n-amyl ketone, cyclohexanone, PGMEA, or ethyl lactate as the organic solvent (E).

  An organic solvent (E) may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

<Organic solvent (F)>
In the interlayer filling layer forming coating liquid of the present invention, an organic solvent (F) having a boiling point of less than 120 ° C. may be used in combination with the organic solvent (E) having a boiling point of 120 ° C. or higher. By using the organic solvent (F) in combination, the evaporation efficiency of the organic solvent in the B-stage process can be increased.
However, if the boiling point of the organic solvent (F) is excessively low, a problem of evaporation roughness occurs. Therefore, the boiling point of the organic solvent (F) is preferably 60 ° C. or more, and particularly preferably 65 to 115 ° C. .

  As such an organic solvent (F), among the above-mentioned various organic solvents, those having a boiling point of less than 120 ° C. may be selected and used. In particular, the boiling point is within the above preferred range, and the organic solvent From the viewpoint of uniform mixing with (E) and good resin solubility, propyl alcohol, isopropyl alcohol, tert-butanol, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, propyl acetate, and isobutyl acetate are preferred.

  An organic solvent (F) may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

<Content>
In the coating solution for forming the interlayer filling layer of the present invention, the mixing ratio of the organic solvent (E) to the other components other than the organic solvent (total solid content other than the organic solvent in the coating solution for forming the interlayer filling layer) is particularly limited. However, it is preferably 20% by weight or more and 70% by weight or less, particularly preferably 30% by weight or more and 60% by weight or less with respect to the other components, and the solid content concentration in the coating solution is 10 to 80% by weight, particularly It is preferable to set it as 20 to 70 weight%. By setting it as such a mixing ratio, it can be set as the coating liquid excellent in the handleability with the appropriate viscosity which can form a favorable coating film by arbitrary coating methods.
If the mixing ratio of the organic solvent (E) is lower than the above lower limit, the viscosity of the coating solution may increase and a good coating film may not be obtained, or if the upper limit is exceeded, a predetermined film thickness may not be obtained. There is a possibility of coming out.

  When the organic solvent (F) is used in combination with the organic solvent (E), the total mixing ratio thereof is preferably within the above range. Further, in order to effectively obtain the effect of the combined use of the organic solvent (E) and the organic solvent (F), the organic solvent (E) and the organic solvent (F) are expressed in terms of% by weight. F) = 95 to 50: 5 to 50, and particularly preferably 90 to 60:10 to 40 (the total amount of the organic solvent (E) and the organic solvent (F) is 100% by weight).

[Curing agent (C)]
The coating solution for forming an interlayer filling layer of the present invention may contain a curing agent (C) as necessary.

  The curing agent (C) used in the present invention refers to a substance that contributes to the crosslinking reaction between the crosslinking groups of the thermosetting resin (A), such as the epoxy group of the epoxy resin (a).

  There is no restriction | limiting in particular as a hardening | curing agent (C), According to the kind of thermosetting resin to be used, it selects and uses. When the thermosetting resin is an epoxy resin, any one generally known as an epoxy resin curing agent can be used. For example, phenolic curing agents, aliphatic amines, polyether amines, alicyclic amines, aromatic amines and other amine curing agents, acid anhydride curing agents, amide curing agents, tertiary amines, imidazoles and the like Derivatives, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan curing agents, isocyanate curing agents, blocked isocyanate curing agents, and the like.

  Specific examples of the phenolic curing agent include bisphenol A, bisphenol F, 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl ether, 1,4-bis (4-hydroxyphenoxy) benzene, 1,3-bis. (4-hydroxyphenoxy) benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, phenol novolak, bisphenol A novolak, o-cresol novolak, m-cresol novolak, p-cle All novolak, xylenol novolak, poly-p-hydroxystyrene, hydroquinone, resorcin, catechol, t-butylcatechol, t-butylhydroquinone, fluoroglycinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2 , 4-Benzenetriol, 2,3,4-trihydroxybenzophenone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2, -Dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allylated or polyallylated dihydroxynaphthalene, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, allylated pyrogallol, etc. The

  Specific examples of the amine curing agent include aliphatic diamines such as ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, Examples include diethylenetriamine, iminobispropylamine, bis (hexamethylene) triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, tetra (hydroxyethyl) ethylenediamine, and the like. Examples of polyether amines include triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis (propylamine), polyoxypropylene diamine, polyoxypropylene triamines, and the like. Cycloaliphatic amines include isophorone diamine, metacene diamine, N-aminoethylpiperazine, bis (4-amino-3-methyldicyclohexyl) methane, bis (aminomethyl) cyclohexane, 3,9-bis (3-amino). Propyl) -2,4,8,10-tetraoxaspiro (5,5) undecane, norbornenediamine and the like. Aromatic amines include tetrachloro-p-xylenediamine, m-xylenediamine, p-xylenediamine, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, 2,4-diaminoanisole, 2,4 -Toluenediamine, 2,4-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-1,2-diphenylethane, 2,4-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, m-aminophenol, m-aminobenzylamine, benzyldimethylamine, 2-dimethylaminomethyl) phenol, triethanolamine, methylbenzylamine, α- (m-aminophenyl) ethylamine, α- (p-aminophenyl) ethylamine , Diaminodiethyl Examples include rudimethyldiphenylmethane, α, α'-bis (4-aminophenyl) -p-diisopropylbenzene.

  Specific examples of acid anhydride curing agents include dodecenyl succinic anhydride, polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, poly (ethyloctadecanedioic acid) anhydride, poly (phenylhexadecanedioic acid) Anhydride, Methyltetrahydrophthalic anhydride, Methylhexahydrophthalic anhydride, Hexahydrophthalic anhydride, Methylhymic anhydride, Tetrahydrophthalic anhydride, Trialkyltetrahydrophthalic anhydride, Methylcyclohexene dicarboxylic anhydride, Methylcyclohexene tetracarboxylic Acid anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitic dianhydride, het anhydride, nadic anhydride, methyl nadic anhydride, 5- ( 2, -Dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene-2-succinic acid Examples of the anhydride include 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride and the like.

  Examples of the amide type curing agent include dicyandiamide and polyamide resin.

  Examples of the tertiary amine include 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol. .

  Examples of imidazole and derivatives thereof include 1-cyanoethyl-2-phenylimidazole, 2-phenylimidazole, 2-ethyl-4 (5) -methylimidazole, 2-phenyl-4-methylimidazole, and 1-benzyl-2-methylimidazole. 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazo Lithium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methyl Imidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-dia No-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Examples include phenyl-4-methyl-5-hydroxymethylimidazole and adducts of an epoxy resin and the imidazoles.

  Examples of organic phosphines include tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine and the like, and phosphonium salts include tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenylborate, Examples include tetrabutylphosphonium / tetrabutylborate, and examples of the tetraphenylboron salt include 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / tetraphenylborate, and the like.

  These hardening | curing agents (C) may be used individually by 1 type, and 2 or more types may be mixed and used for them in arbitrary combinations and ratios.

  Among the above curing agents, imidazole or its derivatives and dicyandiamine compounds are preferably used.

  When the organic carboxylic acid ester whose decomposition product has an epoxy resin curing action is used as the surface activator (D), the organic carboxylic acid ester is used as the curing agent (C). It may be used as

It is preferable that content of the hardening | curing agent (C) in the coating liquid for interlayer filling layer formation of this invention shall be 0.1-60 weight part with respect to 100 weight part of thermosetting resins (A).
In particular, when the curing agent (C) is a phenol-based curing agent, an amine-based curing agent, or an acid anhydride-based curing agent, the equivalent ratio of the epoxy group in the epoxy resin to the functional group in the curing agent is 0.8 to It is preferable to use it in the range of 1.5. Outside this range, unreacted epoxy groups and functional groups of the curing agent may remain, and desired physical properties may not be obtained.
Curing agents are amide-based curing agents, tertiary amines, imidazoles and their derivatives, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan-based curing agents, isocyanate-based curing agents. In the case of a curing agent, a blocked isocyanate curing agent, etc., it is preferably used in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin.

  In the case of a dicyandiamine compound, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin.

[Other additives]
The coating liquid for forming the interlayer filling layer of the three-dimensional integrated circuit of the present invention may contain various additives within the range not impairing the effects of the present invention for the purpose of further improving the functionality.

As such other additives, as an additive component for improving the adhesion between the substrate and the matrix resin and the inorganic filler, a coupling agent such as a silane coupling agent or a titanate coupling agent, Examples thereof include an ultraviolet ray inhibitor, an antioxidant, a plasticizer, a flame retardant, a colorant, a dispersant, a fluidity improver, and an adhesion improver with a base material for improving storage stability.
In addition, thermoplastic oligomers can also be added to the coating liquid for forming an interlayer filling layer of the present invention from the viewpoint of improving fluidity during molding and improving adhesion to a substrate.
In addition, surfactants, emulsifiers, low elasticity agents, diluents, antifoaming agents, ion trapping agents, and the like that improve the dispersibility of each component in the coating solution can be added.
Any of these may be used alone or in a combination of two or more in any combination and ratio.

  There is no restriction | limiting in particular in the compounding quantity of another additive, It is used with the compounding quantity of a normal resin composition to such an extent that required functionality is obtained.

Among the above additives, it is preferable to include a coupling agent from the viewpoint of improving the adhesion between the thermosetting resin component and the inorganic filler (B).
Here, as the silane coupling agent, epoxy silane such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ, -Aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyltri Aminosilane such as ethoxysilane, mercaptosilane such as 3-mercaptopropyltrimethoxysilane, p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysila And vinyl silanes such as γ-methacryloxypropyltrimethoxysilane, and epoxy, amino and vinyl polymer type silanes.

  On the other hand, titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl / aminoethyl) titanate, diisopropyl bis (dioctyl phosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis ( Ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate It is done.

  A coupling agent may be used individually by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

  The addition amount of the coupling agent is preferably about 0.1 to 2.0% by weight with respect to the total solid content in the coating liquid for forming the interlayer filling layer. If the amount of the coupling agent is small, the effect of improving the adhesion between the matrix resin and the inorganic filler due to the incorporation of the coupling agent cannot be sufficiently obtained, and if it is too much, the coupling agent is obtained from the cured film obtained. There is a problem that bleeds out.

  Thermoplastic oligomers include C5 and C9 petroleum resins, styrene resins, indene resins, indene / styrene copolymer resins, indene / styrene / phenol copolymer resins, indene / coumarone copolymer resins, indene / benzothiophene. Examples thereof include copolymer resins. The addition amount is usually in the range of 2 to 30 parts by weight with respect to 100 parts by weight of the thermosetting resin (A).

As the surfactant, any of conventionally known anionic surfactants, nonionic surfactants, and cationic surfactants can be used.
For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfates, alkyl Examples include sulfonates, sulfosuccinate esters, alkylbetaines, amino acids, and the like.
In addition, fluorine surfactants in which some or all of the CH bonds are CF bonds in these surfactants can also be preferably used.

  Surfactant may be used individually by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

  The addition amount of the surfactant is preferably about 0.001 to 5% by weight with respect to the total solid content in the coating liquid for forming the interlayer filling layer. If the addition amount of the surfactant is less than the above lower limit, the predetermined film thickness uniformity may not be obtained, and if it exceeds the upper limit, phase separation from the thermosetting resin component may be caused.

[Method for producing coating liquid]
The manufacturing method of the coating liquid of this invention is not specifically limited, What is necessary is just to follow a conventionally well-known method, and can manufacture by mixing the structural component of a coating liquid. At that time, for the purpose of improving the uniformity of the composition, defoaming, etc., it may be mixed using a paint shaker, bead mill, planetary mixer, stirring type disperser, self-revolving stirring mixer, three rolls, etc. preferable.
The mixing order of each compounding component is arbitrary as long as there is no particular problem such as reaction or precipitation, and any two components or three or more components of the coating solution are mixed in advance, and then the remaining components are mixed. The components may be mixed or all at once.

[Method of manufacturing a three-dimensional integrated circuit]
Below, the manufacturing method of the three-dimensional integrated circuit which uses the coating liquid for interlayer filling layer formation of this invention is demonstrated.

  The method for producing a three-dimensional integrated circuit of the present invention comprises: a coating process for coating the interlayer filling layer forming coating liquid of the present invention on a semiconductor substrate surface to form a coating film; and a semiconductor substrate on which the coating film is formed. And a bonding step of laminating and pressurizing with another semiconductor substrate, and usually drying the coating film into a B-stage between the coating step and the bonding step (hereinafter referred to as “B-stage forming step”) .)

  The method for manufacturing a three-dimensional integrated circuit according to the present invention will be specifically described below.

<Application process>
In the production method of the present invention, first, a coating film of the coating liquid for forming an interlayer filling layer of the present invention is formed on the surface of a semiconductor substrate.
That is, a coating film is formed by the dip method, spin coating method, spray coating method, blade method, or any other method using the interlayer filling layer forming coating solution of the present invention. A coating film having a predetermined film thickness can be uniformly formed on a semiconductor substrate by using a coating apparatus such as a spin coater, a slit coater, a die coater, or a blade coater for coating the coating liquid of the present invention. It is preferable.

<B-stage process>
In order to remove the solvent and low molecular components from the coating film formed by applying the coating liquid of the present invention, it is usually heat-treated at an arbitrary temperature of 50 to 150 ° C., preferably 70 to 120 ° C. for about 10 to 120 minutes. To form a B-staged film.

If the heating temperature for the B-stage formation is too low or the heating time is too short, the organic solvent in the coating film cannot be sufficiently removed, and the organic solvent remains in the resulting B-stage formation film. The organic solvent thus evaporated evaporates by high-temperature treatment in the next bonding step, and the evaporation trace of the residual solvent becomes a void, so that an interlayer filling layer having high thermal conductivity, high insulation, and a predetermined physical strength cannot be formed. On the other hand, if the heating temperature for B-stage formation is too high or the heating time is too long, curing of the resin proceeds and a good B-stage film cannot be obtained. Accordingly, the heating condition for the B-stage film varies depending on the film thickness of the formed B-stage film, the boiling point of the organic solvent in the coating solution, and the type of the thermosetting resin used. Is 1 to 50 μm, it is preferably about 30 to 120 minutes at 70 to 110 ° C., and preferably about 80 to 120 minutes at 80 to 120 ° C. if the B-staged film thickness is 50 to 200 μm.
At this time, the heat treatment may be performed at a constant temperature, but the heat treatment may be performed under a reduced pressure condition in order to smoothly remove volatile components such as an organic solvent in the coating solution. Moreover, you may perform the heat processing by a stepwise temperature rise in the range in which hardening of a thermosetting resin (A) does not advance. For example, first, heat treatment may be performed at 50 to 70 ° C., for example, 60 ° C., then at 70 to 90 ° C., for example, 80 ° C., and further at 90 to 150 ° C., for example, 120 ° C. for about 5 to 30 minutes. it can.

  In addition, since the interlayer filling layer forming coating solution of the present invention has sufficient stretchability suitable for film forming, the interlayer filling layer forming coating solution of the present invention is formed into a film and the film is placed on a semiconductor substrate. By doing so, you may form into a film. According to the coating liquid for forming an interlayer filling layer of the present invention, even in this case, a uniform film can be formed while preventing deterioration of film quality due to evaporation evaporation during film formation.

<Joint process>
Next, after the formed B-stage film is heated to exhibit tackiness, temporary bonding is performed with the semiconductor substrate to be bonded. Although it depends on the thermosetting resin (A) used, the temperature for temporary bonding is preferably 80 to 150 ° C., and more preferably 90 to 140 ° C. for about 1 second to 120 seconds. When the semiconductor substrate is bonded to a plurality of layers, the temporary bonding may be repeated for the number of layers of the substrate, or a plurality of substrates on which the B-staged film is formed are overlapped, and then heated and collectively bonded. You may do it. In the temporary bonding, it is preferable to apply a load of 1 gf / cm ^{2 to 5} Kgf / cm ² between the laminated substrates as necessary.

After the temporary bonding, the semiconductor substrate is finally bonded.
In the main bonding, the melt viscosity of the thermosetting resin (A) in the B-staged film is increased by pressing the temporarily bonded semiconductor substrate at a temperature of 200 ° C. or higher, preferably 220 ° C. or higher for about 10 to 60 seconds. This is performed by lowering and promoting the connection of electrical terminals between the semiconductor substrates, and at the same time activating the surface activator (D) in the B-staged film to realize solder bonding between the semiconductor substrates. The upper limit of the heating temperature for the main bonding is a temperature at which the thermosetting resin (A) to be used is not decomposed or altered, and is appropriately determined depending on the type and grade of the resin, but is usually 300 ° C. or lower.
In addition, it is preferable to apply a load of 10 gf / cm ² to 10 Kgf / cm ² between the substrates as needed during the heat bonding.

EXAMPLES Hereinafter, although this invention is demonstrated still in detail using an Example, this invention is not limited to a following example, unless it deviates from the meaning.

[Composition ingredients]
The compounding components of the coating solution for forming the interlayer filling layer used in the following are as follows.
<Epoxy resin (a)>
Epoxy resin (a1): Phenoxy resin
Weight average molecular weight: 26,000
Epoxy equivalent: 4,600 g / equivalent
30% by weight methyl ethyl ketone / cyclohexanone solution Epoxy resin (a2): Product name “YL6800” manufactured by Mitsubishi Chemical Corporation
Epoxy resin (a3): Mitsubishi Chemical Corporation product name “1032H60”
Epoxy resin (a4): Mitsubishi Chemical Corporation product name “1001”
Epoxy resin (a5): Mitsubishi Chemical Corporation product name “4004”

<Inorganic filler (B)>
Boron nitride BN (thermal conductivity 3 W / mK (thickness direction), manufactured by Nissin Reflatec Co., Ltd.,
275W / mK (in-plane direction))
<Curing agent (C)>
2-phenyl-4,5-dihydroxymethylimidazole manufactured by Shikoku Chemicals Co., Ltd.
Product name "2PHZ-PW"
<Surfactant (D)>
Adipic acid reagent special grade manufactured by Wako Pure Chemical Industries, Ltd.

<Organic solvent (E)>
Organic solvent (E1): Wako Pure Chemical Industries, Ltd. Cyclohexanone (CHN)
(Boiling point 157 ° C.) Reagent special grade organic solvent (E2): Propylene glycol monomethyl ether manufactured by Wako Pure Chemical Industries, Ltd.
Teracetate (PGMEA) (boiling point 146 ° C.) Reagent special grade organic solvent (E3): methyl isobutyl ketone (MIBK) manufactured by Wako Pure Chemical Industries, Ltd.
(Boiling point 118 ° C) Reagent special grade <Organic solvent (F)>
Organic solvent (F1): Methyl ethyl ketone (MEK) manufactured by Wako Pure Chemical Industries, Ltd.
(Boiling point 80 ° C) Reagent special grade Organic solvent (F2): Wako Pure Chemical Industries, Ltd. Acetone (boiling point 56 ° C) Reagent special grade

In addition, the phenoxy resin as the said epoxy resin (a1) was produced as follows.
YL6121H (epoxy equivalent of 171 g / equivalent, 1: 1 mixture of 4,4′-biphenol type epoxy resin and 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol type epoxy resin (Mitsubishi Chemical Corporation) 215 parts by weight, 3,3′-dimethyl-4,4′-biphenol (OH equivalent 107 g / equivalent, manufactured by Honshu Chemical Co., Ltd.) 127 parts by weight, 0.32 parts by weight of a 27% by weight tetramethylammonium hydroxide aqueous solution 228 parts by weight of cyclohexanone as a solvent for reaction was placed in a pressure-resistant reaction vessel equipped with a stirrer, and reacted at 180 ° C. for 5 hours in a nitrogen gas atmosphere. Then, 171 parts by weight of cyclohexanone and 399 parts by weight of methyl ethyl ketone were used as solvents for dilution. The solvent was removed from the reaction product by a conventional method to obtain a 30% by weight resin solution. .

[Evaluation of various physical properties and characteristics]
(1) Melt viscosity of epoxy resin Melt viscosity (parallel plate dynamic viscosity) was measured using a viscoelasticity measuring device Physica MCR301 manufactured by Anton Paar Japan.
First, the solvent was distilled off from the epoxy resin to be measured to obtain a solid, and then the solid was press-molded to obtain a plate sample having a thickness of about 1 mm. This sample was placed between a parallel plate dish and a parallel plate (25 mmφ), and the parallel plate dynamic viscosity was measured.
The measurement condition was that 20% sinusoidal distortion was applied to the sample, the angular frequency of the distortion was 10 rad / sec, and the viscosity was measured from 40 ° C. to 200 ° C. in the process of raising the temperature at a rate of 3 ° C. per minute. .

(2) Thermal conductivity of epoxy resin The cured film of epoxy resin was measured by measuring the thermal diffusivity, specific gravity, and specific heat using the following apparatus, and multiplying these three measured values.
1) Thermal diffusivity: Eye Phase Co., Ltd. “I Phase Mobile 1u”
2) Specific gravity: METTLER TOLEDO Co., Ltd. “Balance XS-204” (Using solid specific gravity measurement kit)
3) Specific heat: Seiko Instruments Inc. “DSC320 / 6200”

(3) Particle size of inorganic filler The coating solution for forming an interlayer filling layer after stirring and mixing was dispersed with cyclohexanone and measured with a particle size distribution measuring device “SALD-2200” manufactured by Shimadzu Corporation. From the obtained particle size distribution, the average particle size and the maximum particle size of the pulverized inorganic filler were determined.

(4) Homogeneity of B-staged film The obtained B-staged film was visually observed and evaluated according to the following criteria.
○: There is no evaporation evaporation of the solvent, and a homogeneous film is formed.
X: The film is heterogeneous due to rough evaporation of the solvent.

(5) Residual solvent amount of B-staged film The obtained B-staged film was dissolved in an organic solvent, and the obtained solution was quantitatively analyzed by gas chromatography (GC) to obtain a B-staged film. The ratio of residual solvent to was calculated.

[Experimental Example 1]
As the epoxy resin (a), 3.33 g of the above epoxy resin (a1) solution, 3.50 g of the epoxy resin (a2), 0.63 g of the epoxy resin (a3) solution (80 wt% cyclohexanone solution) (as a resin excluding the solvent) Mixing weight ratio 20:70:10 The melt viscosity of the mixed epoxy resin (a) of the epoxy resin (a1), the epoxy resin (a2) and the epoxy resin (a3) is 800 Pa · s (50 ° C.) and 4 Pa · s. (120 ° C.) was added 0.20 g of the curing agent (C), 0.15 g of the surface activator (D), and 1.94 g of the organic solvent (E1), and 2000 rpm using a self-revolving stirrer. For 6 minutes to obtain an epoxy resin solution (coating solution).
This resin solution is applied to a separator (silicone-treated polyethylene terephthalate film, thickness: 100 μm), and the solvent is removed by heating at 60 ° C. for 15 minutes, then at 80 ° C. for 15 minutes, and then under reduced pressure at 100 ° C. for 15 minutes. Thus, a B-staged film was obtained. After that, after placing another separator on the obtained B-staged film, it was first cured at 130 ° C. for 1 hour and then at 150 ° C. for 1 hour to obtain a cured film having a thickness of about 100 μm. It was.
When the thermal conductivity of this cured film was measured, the thermal conductivity of the epoxy resin (a) was 0.22 W / mK.

[Experiment 2]
After mixing the surfactant compound shown in Table 1 and an organic solvent (methyl ethyl ketone and cyclohexanone mixed in a mixing weight ratio (35:65)) at the surfactant concentration shown in Table 1, the mixture was stirred and mixed. A surface activator solution was obtained.
After 50 μL of this surface activator solution was dropped on a 10 mm × 10 mm copper substrate, solder balls (Sn3.0Ag0.5Cu, diameter 300 μm) were added to the surface activator droplets. The substrate was heated on a hot plate at 120 ° C. for 1 minute to distill off the solvent.
Next, this substrate was heated on a hot plate at 250 ° C. for 10 seconds at 250 ° C. to evaluate whether the solder balls had good melting properties (◯) or not (×) with respect to the copper substrate. The results are shown in Table 1.

  As is apparent from Table 1, when organic carboxylic acid and organic carboxylic acid ester were used as the surface activator, the solder balls melted at a predetermined temperature to form a good bond with the copper substrate. On the other hand, amino acids have low solubility in solvents, and imidazoles have a low action as a flux and solder balls and copper substrates cannot be joined.

[Preparation of coating solution for forming interlayer filling layer]
<Manufacture example 1: Preparation of the coating liquid of Examples 1-4 and 14-19>
As epoxy resin (a), the above-mentioned epoxy resin (a1) solution 1.67 g, epoxy resin (a2) 1.25 g, epoxy resin (a3) solution (80 wt% cyclohexanone solution) 0.31 g, and epoxy resin (a4) solution (70 wt% cyclohexanone solution) 0.71 g (weight ratio 20: 50: 10: 20 as a resin excluding the solvent. This epoxy resin (a1), epoxy resin (a2), epoxy resin (a3) and epoxy resin ( The melt viscosity of the mixed epoxy resin (a) of a4) is> 1000 Pa · s (50 ° C.) and 12 Pa · s (120 ° C.), and the thermal conductivity is 0.20 W / mK. (B) 2.5 g and 3.11 g of organic solvent (E1) are charged into a PE container, and 12 g of zirconia balls (YTZ-2) having a diameter of 2 mm are added. It was stirred for 30 minutes at 2000rpm using a revolving agitator. After completion of the stirring, the beads are removed by filtration, 0.10 g of the curing agent (C) and 0.05 g of the surface activator (D) are added, and the mixture is further stirred for 6 minutes by a revolving stirrer to apply an interlayer filling layer. A liquid (the solid content concentration was 50% by weight and the content of the inorganic filler (B) was 34% by volume with respect to the total with the epoxy resin (a)) was obtained.
The average particle size of the inorganic filler (B) determined from the particle size distribution of the inorganic filler (B) in the obtained coating liquid for forming the interlayer filling layer after pulverization was 4 μm, and the maximum particle size was 9 μm.
In addition, as said organic solvent, the organic solvent shown in Table 2 was used for every Example.
Each component composition of the coating liquid for forming an interlayer filling layer prepared in Production Example 1 is defined as “Coating liquid composition I”.

[Production Example 2: Preparation of coating solutions of Examples 5 and 6 and Comparative Examples 1 to 3]
In Production Example 1, the organic solvent shown in Table 2 was used for each Example and Comparative Example, and the epoxy resin (a) was changed to 0.31 g of an epoxy resin (a3) solution (80 wt% cyclohexanone solution) and epoxy resin (a4). ) 2.14 g of solution (70 wt% cyclohexanone solution) and 0.75 g of epoxy resin (a5) (weight ratio 10:60:30 as a resin excluding the solvent. This epoxy resin (a3), epoxy resin (a4) The melt viscosity of the mixed epoxy resin (a) of the epoxy resin (a5) is 12000 Pa · s (50 ° C.) and 3 Pa · s (120 ° C.), and the thermal conductivity is 0.21 W / mK. In the same manner, except for the mixed composition, the coating solution for forming the interlayer filling layer (the solid content concentration is 50% by weight and the content of the inorganic filler (B) is based on the total amount with the epoxy resin (a)). 34 vol%) was prepared.
The average particle diameter of the inorganic filler (B) determined from the particle size distribution of the inorganic filler (B) in the obtained coating liquid for forming the interlayer filling layer after pulverization was 3 μm, and the maximum particle diameter was 9 μm.
Each component of the coating liquid for forming the interlayer filling layer prepared in Production Example 2 is referred to as “Coating liquid composition II”.

[Production Example 3: Preparation of coating solutions of Examples 7 to 13]
In Production Example 1, using the organic solvent shown in Table 3 for each Example and Comparative Example, the epoxy resin (a) was 1.67 g of the epoxy resin (a1) solution, 1.25 g of the epoxy resin (a2), and the epoxy resin. (A3) 0.31 g of the solution (80 wt% cyclohexanone solution) and 0.71 g of the epoxy resin (a4) solution (70 wt% cyclohexanone solution) (compounding weight ratio 20: 50: 10: 20 as the resin excluding the solvent). The melt viscosity of the mixed epoxy resin (a) of the epoxy resin (a1), the epoxy resin (a2), the epoxy resin (a3) and the epoxy resin (a4) is 800 Pa · s (50 ° C.) and 4 Pa · s (120 ° C. And the thermal conductivity is 0.22 W / mK.) The coating liquid for forming an interlayer filling layer is similarly formed except that the mixed composition is (solid content concentration is 50% by weight, no The content of the filler (B) was prepared with epoxy resin 34% by volume relative to the total of (a)).
The average particle diameter of the inorganic filler (B) determined from the particle size distribution of the inorganic filler (B) in the obtained coating liquid for forming the interlayer filling layer after pulverization was 3 μm, and the maximum particle diameter was 9 μm.
Each component of the coating liquid for forming the interlayer filling layer prepared in Production Example 3 is referred to as “Coating liquid composition III”.

[Examples 1-6, Comparative Examples 1-3]
Using the organic solvent shown in Table 2, the interlayer filling layer forming coating solution prepared by adopting the coating solution composition shown in Table 2 is stationary on a 2-inch silicon substrate using a spin coater (manufactured by Kyowa Riken Co., Ltd.). After coating at 800 rpm, coating was performed at 800 rpm for 10 seconds, followed by 2000 rpm for 30 seconds, and B-staged under the heating conditions shown in Table 2 to obtain a B-staged film.
In addition, the heat treatment for B-stage was performed in two stages in Examples 1 to 4 and Comparative Examples 1 and 2, and in one stage in Examples 5, 6 and Comparative Example 3.
The obtained B-staged film was evaluated for homogeneity by the method described above, and the results are shown in Table 2.

  From Table 2, by using cyclohexanone having a boiling point of 157 ° C. or PGMEA having a boiling point of 146 ° C., a B-staged film excellent in homogeneity without disturbance of the film quality caused by evaporation of the organic solvent during the B-stage formation is formed. I can see that On the other hand, in Comparative Examples 1 to 3 using acetone having a boiling point of 56 ° C., methyl ethyl ketone having a boiling point of 80 ° C., and methyl isobutyl ketone having a boiling point of 118 ° C., the evaporation rate of the solvent at the time of heating is too high. The resulting film quality is greatly disturbed, and a homogeneous B-stage film cannot be obtained.

[Examples 7 to 19]
Using the organic solvent shown in Table 3, the interlayer filling layer forming coating solution prepared by adopting the coating solution composition shown in Table 3 is stationary on a 2-inch silicon substrate using a spin coater (manufactured by Kyowa Riken Co., Ltd.). After coating at 800 rpm, coating was performed at 800 rpm for 10 seconds, followed by 2000 rpm for 30 seconds, and B-staged under the heating conditions shown in Table 3 to obtain a B-staged film having the thickness shown in Table 3.
The B-stage heat treatment was performed in one stage in Examples 7 to 13, and two stages in Examples 14 to 19.
The obtained B-staged film was evaluated for the amount of residual solvent by the method described above, and the results are shown in Table 3.

  From Table 3, it can be seen that according to the coating solution of the present invention, a B-staged film can be formed with a small amount of residual solvent and no problem of void generation.

According to the present invention, a high-quality interlayer filling layer having high thermal conductivity can be formed simultaneously with bonding of solder bumps between semiconductor device substrates and lands.

Claims (12)

  A thermosetting resin (A) having a thermal conductivity of 0.2 W / mK or more, a melt viscosity at 50 ° C. of 500 Pa · s or more, and a melt viscosity at 120 ° C. of 100 Pa · s or less, and a thermal conductivity of An inorganic filler (B) having a mean particle size of 0.1 μm or more and 5 μm or less and a maximum particle size of 10 μm or less, a surface activator (D), and a boiling point of 120 ° C. or more. A coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit, comprising an organic solvent (E).   The coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit according to claim 1, wherein the boiling point of the organic solvent (E) is 130 ° C or higher and lower than 180 ° C.   The coating solution for forming an interlayer filling layer of a three-dimensional integrated circuit according to claim 1 or 2, further comprising an organic solvent (F) having a boiling point of 60 ° C or higher and lower than 120 ° C.   The inorganic filler (B) is contained in an amount of 5% by volume or more and 60% by volume or less based on the total volume of the thermosetting resin (A) and the inorganic filler (B). A coating solution for forming an interlayer filling layer of the three-dimensional integrated circuit described.   The coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit according to any one of claims 1 to 4, wherein the inorganic filler (B) is a boron nitride filler.   The coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit according to any one of claims 1 to 5, further comprising a curing agent (C).   The coating liquid for forming an interlayer filling layer of a three-dimensional integrated circuit according to claim 6, wherein the curing agent (C) is at least one selected from imidazole, an imidazole derivative, and a dicyandiamine compound.   The interlayer filling layer formation of the three-dimensional integrated circuit according to any one of claims 1 to 7, wherein the surface activator (D) is at least one selected from organic carboxylic acids and organic carboxylic acid derivatives. Coating liquid.   A coating step of applying a coating liquid according to any one of claims 1 to 8 to form a coating film on a surface of a semiconductor substrate, and laminating the semiconductor substrate on which the coating film is formed with another semiconductor substrate A method of manufacturing a three-dimensional integrated circuit.   The method for manufacturing a three-dimensional integrated circuit according to claim 9, further comprising a drying step of drying the coating film between the coating step and the bonding step.   11. The three-dimensional integration according to claim 9, wherein in the coating step, the coating liquid is applied to a semiconductor substrate surface by at least one coating device selected from a spin coater, a slit coater, a die coater, and a blade coater. Circuit manufacturing method.   The method of manufacturing a three-dimensional integrated circuit according to any one of claims 9 to 11, further comprising a heating step of heating to 200 ° C or higher in the bonding step.