JP2015183050A - Insulation film and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation film which is excellent in film characteristics and heat resistance after hardening and has a thermal conductivity of 3.0 W/m K or higher.SOLUTION: An insulation film comprises (A) a novolak type epoxy resin, (B) a butadiene-acrylonitrile copolymer, (C) an aralkyl phenol resin, (D) a hardening catalyst and (E) an insulation filler having a thermal conductivity of 20 W/m K or higher. The content of the ingredient (B) relative to the total of the ingredients (A) to (C) of 100 pts. mass is 10-20 pts. mass, and the content of the ingredient (E) is 60-85 vol.% relative to 100 vol.% of the insulation film.

Description

  The present invention relates to an insulating film and a semiconductor device, and more particularly to an insulating film having excellent heat resistance and thermal conductivity after curing, and a highly reliable semiconductor device including a cured product of the insulating film.

  In the field of semiconductor devices such as power devices, there is an increasing demand for highly thermally conductive insulating materials. On the other hand, in the manufacturing process of a semiconductor device, the semiconductor device being manufactured may be exposed to a high temperature by soldering or the like, and the semiconductor adhesive used in the semiconductor device to improve the heat resistance reliability of the semiconductor device Requires heat resistance. As a material with improved heat resistance, a protective film layer sealant (Patent Document 1) containing a cresol novolac-type epoxy resin, a phenol aralkyl resin, and a phenol-modified xylene resin is disclosed.

  On the other hand, in recent years, an adhesive film is often used instead of an adhesive because of good handling. In this case, the adhesive film is applied on a base film such as polyethylene terephthalate (PET) and supplied as a coating film dried in an uncured state. Film properties such as flexibility are necessary.

JP 2009-91424 A

  However, when used as a high thermal conductivity application, when a high thermal conductive filler is highly filled in a sealant for a protective film layer containing the above cresol novolac type epoxy resin, phenol aralkyl resin, and phenol-modified xylene resin, There is a problem that the film becomes hard and brittle and cannot be formed into a film.

  Then, the objective of this invention is providing the insulating film which is excellent in film property, is excellent in heat resistance after hardening, and has a heat conductivity of 3.0 W / m * K or more.

The present invention relates to an insulating film and a semiconductor device which have solved the above problems by having the following configuration.
[1] (A) novolac type epoxy resin, (B) butadiene acrylonitrile copolymer, (C) aralkylphenol resin, (D) curing catalyst, and (E) insulating filler having a thermal conductivity of 20 W / m · K or more Including
(B) A component is 10-20 mass parts with respect to a total of 100 mass parts of (A)-(C) component, and (E) component is 60-85 with respect to 100 volume% of insulating films. An insulating film characterized by being in volume%.
[2] The insulating film according to [1], wherein the component (D) is an imidazole curing catalyst.
[3] The insulating film according to [1] or [2], wherein the component (E) is at least one selected from the group consisting of aluminum oxide, magnesium oxide, and boron nitride.
[4] The component (E) includes an insulating filler (E1) having an average particle size of 0.1 to 0.8 μm, an insulating filler (E2) having an average particle size of 2 to 6 μm, and an average particle size of 7 to 30 μm. The insulating film according to any one of the above [1] to [3], comprising the insulating filler (E3).
[5] The insulating film according to [4], wherein the average particle size of the component (E3) is 15 to 30 μm.
[6] A semiconductor device comprising a cured product of the insulating film according to any one of [1] to [5].

  According to the present invention [1], an insulating film having excellent film properties and excellent heat resistance after curing and having a thermal conductivity of 3.0 W / m · K or more can be provided.

  According to the present invention [6], a highly reliable semiconductor device can be provided by a cured body of an insulating film having excellent heat resistance and thermal conductivity.

It is a schematic diagram for demonstrating the method of scraping application | coating.

[Insulating film]
The insulating film of the present invention comprises (A) a novolac type epoxy resin, (B) a butadiene acrylonitrile copolymer, (C) an aralkylphenol resin, (D) a curing catalyst, and (E) a thermal conductivity of 20 W / m · K. Including the above insulating filler,
(B) A component is 10-20 mass parts with respect to a total of 100 mass parts of (A)-(C) component, and (E) component is 60-85 with respect to 100 volume% of insulating films. It is characterized by volume%.

  The component (A) imparts heat resistance to the insulating film. The component (A) is preferably a cresol novolak type epoxy resin from the viewpoint of heat resistance. Specifically, the cresol novolak type epoxy resin is represented by the formula (1):

(Wherein, n represents an average value and is 1 to 10, preferably 1 to 5.), a cresol novolak type epoxy resin. The epoxy equivalent of the component (A) is preferably 150 to 300 g / eq from the viewpoint of heat resistance after curing of the composition for an insulating film. The composition for an insulating film will be described later. (A) As a commercial item of a component, the cresol novolak-type epoxy resin (product name: N-665-EXP) made from DIC is mentioned. (A) A component may be individual or may use 2 or more types together.

  (B) A component is used for film properties, such as a softness | flexibility, and can use a liquid thing at normal temperature. Examples of the component (B) include butadiene acrylonitrile copolymers that are liquid at room temperature, for example, having a relatively low average molecular weight. As the component (B), a butadiene acrylonitrile copolymer having a group that reacts with an epoxy group at the terminal can be used. Component (B) is, in particular, (A) reactive with a novolac type epoxy resin and (A) compatible with a novolak type epoxy resin, carboxyl group-terminated butadiene acrylonitrile copolymer, amino group-terminated butadiene acrylonitrile. A copolymer and an epoxy group-terminated butadiene acrylonitrile copolymer are preferred. 10-40 mass% is preferable and, as for the acrylonitrile content of these butadiene acrylonitrile copolymers, 15-30 mass% is more preferable. In the case of a carboxyl group-terminated butadiene / acrylonitrile copolymer, the carboxyl group ratio is preferably 1.8 to 3.0%. The component (B) preferably has a weight average molecular weight of 3,000 to 5,000. The weight average molecular weight is a value obtained by gel permeation chromatography (GPC) using a standard polystyrene calibration curve. (B) As a commercial item of a component, Ube Industries butadiene acrylonitrile rubber | gum (Product name: HYCAR CTBN1300 is mentioned. (B) A component may be individual or may use 2 or more types together.

  As the component (C), the formula (2):

(In the formula, R ₁ independently represents a halogen atom, a hydroxyl group, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a phenyl group, and r is 0. An integer of ˜3, preferably r is 0, m is an average value, 1 to 10, preferably 1 to 5, and particularly preferably 1.). . By blending the component (C), the heat resistance and crack resistance of the cured insulating film can be improved. (C) As a commercial item of a component, Mitsui Chemicals aralkyl phenol resin (product name: XLC4L) is mentioned.

  (D) A component should just have the hardening ability of an insulating film. With the component (D), the curing time of the insulating film can be shortened, and the curing process can be shortened. Moreover, the (D) component improves the curability of the insulating film, and the cured insulating film has good characteristics. Examples of the component (D) include imidazole-based curing catalysts, amine-based curing catalysts, carboxylic acid dihydrazide curing catalysts, and the like. From the viewpoint of curability of the insulating film, an imidazole-based curing catalyst is more preferable.

  Examples of the imidazole curing catalyst include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2,4- Diamino-6- [2′-methylimidazolyl- (1 ′)] ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2, Examples include 3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, and the like, such as 2-ethyl-4-methylimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′). )] Ethyl-s-triazine and the like are preferable from the viewpoint of the curing rate of the insulating film.

  Examples of the amine curing catalyst include chain aliphatic amines, cycloaliphatic amines, aliphatic aromatic amines, aromatic amines, and the like, and aromatic amines are preferable. Examples of the carboxylic acid dihydrazide curing catalyst include adipic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, and adipic acid dihydrazide is preferable.

  As a commercial item of (D) component, Shikoku Kasei 2-ethyl-4-methylimidazole (product name: 2E4MZ), Shikoku Kasei 2,4-diamino-6- [2'-methylimidazolyl- (1 ')] -Ethyl-s-triazine (product name: 2MZ-A), Nippon Kayaku's amine curing agent (product name: Kayahard A-A), Nippon Finechem's adipic acid dihydrazide (product name: ADH), and the like. Ingredients are not limited to these product names. (D) A component may be individual or may use 2 or more types together.

As the component (E), aluminum oxide (alumina, Al ₂ O ₃ ), magnesium oxide (MgO), zinc oxide (ZnO), boron nitride (BN), silicon carbide (SiC), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), diamond and the like. The component (E) is preferably at least one selected from the group consisting of aluminum oxide, magnesium oxide, and boron nitride from the viewpoint of durability against thermal conductivity, humidity, and the like. As an example of the thermal conductivity measurement result of each material (unit is W / m · K), Al ₂ O ₃ is 20 to 40, MgO is 45 to 60, ZnO is 54, BN is 30 to 80, SiC is 140 to 170, AlN is 150 to 250, Si ₃ N ₄ is 30 to 80, and diamond is 1000 to 2000. (E) Component commercial products include spherical alumina (Al ₂ O ₃ ) powder (product names: ASFP-20, DAM-03, DAM-05, DAM-07) manufactured by Denki Kagaku Kogyo, and spherical alumina (Al ₂ O ₃ ) powder (product name: CB-A20S), and magnesium oxide powder (product name: SMO-05) manufactured by Sakai Chemical Industry.

The component (E) includes an insulating filler (E1) having an average particle size of 0.1 to 0.8 μm, an insulating filler (E1) having an average particle size of 2 to 6 μm, and an insulating filler having an average particle size of 7 to 30 μm. (E3) is preferably included. By using fillers of these particle sizes in combination, the insulating filler is more densely distributed in the insulating film, so that the thermal conductivity of the insulating film after curing is higher even with the same amount of insulating filler. can do. Here, the average particle size of the component (E) is measured by a laser analysis type particle size analyzer. (E) A component may be individual or may use 2 or more types together.

  (E3) It is more preferable from a viewpoint of thermal conductivity that the average particle diameter of a component is 15-30 micrometers. By containing a filler having a coarse particle size in the component (E), higher thermal conductivity can be given to the insulating film after curing. However, when an insulating filler having an average particle size exceeding 30 μm is contained, the coating film surface of the insulating film composition becomes rough due to the coarse particles, and the appearance of the coating film is impaired, or streaks are generated when the insulating film composition is applied. In addition, problems such as damage to the insulating properties of the cured insulating film are likely to occur, so that it is difficult to obtain a thin insulating film.

  (A) A component is preferable in it being 30-50 mass parts with respect to a total of 100 mass parts of (A)-(C) component.

  (B) component is 10-20 mass parts with respect to a total of 100 mass parts of (A)-(C) component, and when it is less than 10 mass parts, an insulating film becomes hard and defects, such as a crack, exist. It tends to occur and film properties cannot be obtained. On the other hand, when the component (B) exceeds 20 parts by mass, the resin component becomes too soft, and the contact with the insulating filler of the component (E) is weakened, so that the thermal conductivity is lowered.

  The phenol equivalent of component (C) is preferably 1.0 to 1.6 times, more preferably 1.2 to 1.4 times the epoxy equivalent of component (A). If it is less than 1.0 times, sufficient heat resistance cannot be obtained. On the other hand, when the phenol equivalent of (C) component exceeds 1.6 times, hardened | cured material will become hard and weak and it will become easy to crack.

  The component (D) is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the total of the components (A) to (D) from the viewpoint of storage stability and curability of the insulating film.

  (E) A component is 60-85 volume% with respect to 100 volume% of insulating films, and if it is less than 60 volume%, the required thermal conductivity will not be obtained, and when it exceeds 85 volume%, it is for insulating films. The film properties of the composition are deteriorated, the insulating film becomes brittle, or the adhesive strength of the insulating film after curing is lowered. Moreover, it is preferable when 5-15 mass% of (E1), 5-55 mass% of (E2), and 35-85 mass% of (E3) are included with respect to the insulating filler total mass. From the viewpoint of thermal conductivity, (E3) preferably has an average particle size of 15 to 30 μm, and (E3) in this case is preferably contained in an amount of 30 to 50% by mass with respect to the total mass of the insulating filler.

[Insulating film composition]
An insulating film composition (hereinafter also referred to as a composition) for forming an insulating film contains the above-described components (A) to (E). In addition, the composition for an insulating film is an additive such as a silane coupling agent, a tackifier, an antifoaming agent, a flow regulator, a film forming auxiliary agent, a dispersing agent, etc., as long as the effects of the present invention are not impaired. Organic solvents can be included.

  Examples of the organic solvent include aromatic solvents such as toluene and xylene, and ketone solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone. The organic solvents may be used alone or in combination of two or more. Moreover, the usage-amount of an organic solvent is although it does not specifically limit, It is preferable to use so that solid content may be 20-50 mass%. From the viewpoint of workability, the insulating film composition preferably has a viscosity range of 200 to 3000 mPa · s. The viscosity is a value measured using an E-type viscometer at a rotation speed of 10 rpm and 25 ° C.

    This composition can be obtained by dispersing the component (E) in a liquid raw material containing the components (A) to (D) dissolved in an organic solvent. The apparatus for dissolving or dispersing these raw materials is not particularly limited, and a dissolver, a planetary mixer, a likai machine, a three-roll mill, a ball mill, a bead mill and the like can be used. These devices may include a heating device. You may use combining these apparatuses suitably.

  The insulating film can be obtained by applying the above-described composition to a desired support and then drying. The support is not particularly limited, and examples thereof include metal foils such as copper and aluminum, organic films such as polyester resins, polyethylene resins, and polyethylene terephthalate resins. The support may be release-treated with a silicone compound or the like.

  The method for applying the composition to the support is not particularly limited, but the microgravure method, the slot die method, and the doctor blade method are preferable from the viewpoint of film thickness reduction and film thickness control. By the slot die method, an insulating film having a thickness after thermosetting of 10 to 300 μm can be obtained.

  The drying conditions can be set as appropriate according to the type and amount of the organic solvent used in the composition, the thickness of the coating, and the like, for example, at 50 to 120 ° C. and about 1 to 30 minutes. it can. The insulating film thus obtained has good storage stability. In addition, an insulating film can be peeled from a support body at a desired timing.

  For example, the insulating film can be thermally cured at 130 to 220 ° C. for 30 to 180 minutes to adhere the adherend. When bonding the adherend that is a heating element and the adherend that is a heat receiving body, the cured insulating film releases heat from the adherend that is the heating element to the adherend side that is the heat receiving body, It plays the role of heat transfer to dissipate heat on the adherend side which is a heat receiver. Furthermore, the cured insulating film plays a role of relieving stress caused by a difference in coefficient of thermal expansion between the adherend that is a heating element and the adherend that is a heat receiving body.

  The thickness of the insulating film is preferably 10 μm or more and 300 μm or less, more preferably 20 μm or more and 150 μm or less. If it is less than 10 μm, the desired insulating property may not be obtained. When it exceeds 300 μm, there is a possibility that heat dissipation of the adherend that generates heat cannot be sufficiently performed.

  The cured insulating film preferably has a thermal conductivity of 3 W / m · K or more. Further, when the thermal conductivity of the cured insulating film is less than 3 W / m · K, heat transfer from the heating element to the heat receiver may be insufficient. The thermal conductivity of the cured insulating film can be controlled by the type and content of component (E).

The cured insulating film preferably has a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more. The high thermal conductivity layer preferably has a volume resistivity of 1 × 10 ¹² Ω · cm or more, and more preferably 1 × 10 ¹³ Ω · cm or more. When the volume resistivity of the cured insulating film is less than 1 × 10 ¹⁰ Ω · cm, the insulation required for the semiconductor device may not be satisfied.

[Semiconductor device]
The semiconductor device of the present invention includes a cured body of the above-described insulating film. A highly reliable semiconductor device can be provided by a cured body of an insulating film having excellent heat resistance and thermal conductivity. As a semiconductor device, a heating element such as a module or an electronic component and a heat receiving body such as a substrate are bonded with a cured product of an insulating film, or the heat of a substrate that receives heat from the heating element, Furthermore, what adhered the heat sink etc. which receive heat with the hardened | cured material of an insulating film is mentioned.

  The present invention will be described with reference to examples, but the present invention is not limited thereto. In the following examples, parts and% indicate parts by mass and mass% unless otherwise specified.

[Examples 1-9, Comparative Examples 1-7]
First, the (A) component, the (B) component, and the (C) component were dissolved and diluted with MEK so that NV (nonvolatile content, that is, the (A) to (C) components) was 30% by mass. Next, in order of the components (A) to (C) and (D), the additive, and the component (E), a predetermined amount of each raw material is weighed in a container, and is stirred for 5 minutes with a rotating / revolving stirrer (Mazerustar). After stirring and mixing, dispersion is performed using a planetary mixer, and the viscosity is 1000 to 5000 mPa.s with MEK. The composition for insulating films was adjusted to s.

〔Evaluation method〕
1. Measurement of Thermal Conductivity The obtained composition for an insulating film was scraped and applied on a 50 μm-thick PET film to which a release agent was applied so that the film thickness after drying was 200 to 500 μm. In FIG. 1, the schematic diagram for demonstrating the method of scraping application | coating is shown. First, spacers are stacked in two rows on a PET film with a release agent so as to have an appropriate thickness, and then attached with an adhesive tape (FIG. 1 (A)). An appropriate amount of the composition for an insulating film is poured onto a PET film with a release agent (FIG. 1B). A slide glass is placed on a spacer, and the composition for an insulating film is scraped off and applied (FIGS. 1C to 1E). Next, after sufficiently drying the applied composition for insulating film, the obtained insulating film is peeled off from the PET film and cured under the conditions of 200 ° C. × 60 minutes and 0.1 MPa using a vacuum press. It was. The cured insulating film was cut into 10 × 10 mm to prepare a test piece for measuring thermal conductivity. The thermal conductivity of the manufactured test piece for measuring thermal conductivity was measured with a thermal conductivity meter (model number: LFF447 Nanoflash) manufactured by NETSCH. Tables 1 and 2 show the measurement results of thermal conductivity.

2. Film properties Using a coating machine, the obtained composition for an insulating film is placed on a PET film having a thickness of 20 μm on a 50 μm-thick PET film to which a release agent has been applied so that the film thickness after drying becomes 50 to 100 μm. Applied. The applied composition for an insulating film was dried at 80 ° C. for 20 minutes to obtain an insulating film. The obtained insulating film was wound up on a reel with a width of 50 mmφ and a width of 40 cm, and the film property was visually evaluated. Since there was sufficient flexibility, a case where no crack was generated was indicated as “◯”, and a case where a crack was generated was indicated as “X”. Tables 1 and 2 show the film properties.
3. Solder heat resistance Using a coating machine, the obtained composition for an insulating film is placed on a 50 μm-thick PET film to which a release agent is applied so that the film thickness after drying is 50 to 100 μm. And applied. The applied composition for an insulating film was dried at 80 ° C. for 20 minutes to obtain an insulating film with a PET film. The PET film was peeled off from the obtained insulating film with PET film, sandwiched between two 50 mm × 100 mm × 30 μm copper foils, and cured using a vacuum press at 200 ° C. for 60 minutes at 0.1 MPa. . The cured sample was cut into 30 × 30 mm, immersed in a solder bath at 290 ° C. for 2 minutes, and visually evaluated. Here, as the solder in the solder bath, Japanese superior lead-free solder (product name: SN96Cl (010), tin: silver: copper: flux = 91.7: 4: 1.3: 3 (mass%)) was used. The case where the cured sample has no peeling or blistering is indicated as “◯”, and the case where the cured sample has peeling and / or swelling is indicated as “X.” Tables 1 and 2 show the results of solder heat resistance. Show.

  As can be seen from Tables 1 and 2, in all of Examples 1 to 9, all results of thermal conductivity, film properties, and solder heat resistance were good. On the other hand, Comparative Example 1 having too much component (E) had poor film properties. (E) The comparative example 2 with too few components had low heat conductivity. (B) The comparative example 3 which has too many components also had low heat conductivity. (B) The comparative example 4 with too few components had bad film property. Comparative Example 5 using phenol-modified xylene instead of the component (C) also had poor film properties. Comparative Example 6 using an acid anhydride system instead of the component (C) also had poor film properties. Comparative Example 7 using bisphenol A type epoxy resin instead of the (A) component and the (C) component had poor solder heat resistance.

  As described above, the insulating film of the present invention has excellent film properties and excellent heat resistance after curing, and has a thermal conductivity of 3.0 W / m · K or more. A semiconductor device with a high level can be provided.

Claims (6)

(A) a novolac type epoxy resin, (B) a butadiene acrylonitrile copolymer, (C) an aralkylphenol resin, (D) a curing catalyst, and (E) an insulating filler having a thermal conductivity of 20 W / m · K or more,
(B) A component is 10-20 mass parts with respect to a total of 100 mass parts of (A)-(C) component, and (E) component is 60-85 with respect to 100 volume% of insulating films. An insulating film characterized by being in volume%.   The insulating film according to claim 1, wherein the component (D) is an imidazole curing catalyst.   The insulating film according to claim 1 or 2, wherein the component (E) is at least one selected from the group consisting of aluminum oxide, magnesium oxide, and boron nitride.   The component (E) is an insulating filler (E1) having an average particle size of 0.1 to 0.8 μm, an insulating filler (E2) having an average particle size of 2 to 6 μm, and an insulating filler having an average particle size of 7 to 30 μm. The insulating film of any one of Claims 1-3 containing (E3).   (E3) The insulating film of Claim 4 whose average particle diameter of a component is 15-30 micrometers.   The semiconductor device containing the hardened | cured material of the insulating film of any one of Claims 1-5.