Patent Application
20250174506
The embodiment relates to a resin composition, a resin film, a printed wiring board, and a semiconductor package.
Miniaturization and increasing performance of electronic devices in recent years have also moved the fields of printed wiring boards and semiconductor packages toward higher wiring density and integration.
In an electronic device as such, an insulating material such as a thermosetting resin is used as a protective material for a semiconductor chip, a substrate material for a printed wiring board, and the like; however, stress generated due to a difference in thermal expansion coefficient between the insulating material and the semiconductor chip can be a problem. The generated stress may cause a warpage of a semiconductor package, resulting in a decrease in reliability.
As a method for bringing the thermal expansion coefficient of an insulating material closer to the thermal expansion coefficient of a semiconductor chip, a method of blending an inorganic filler with the insulating material is being practiced.
PTL 1 discloses a thermosetting resin composition that forms a cured product having low thermal expansivity and low hygroscopicity, the thermosetting resin containing an epoxy resin composition and an inorganic filler, in which the epoxy resin composition contains a biphenyl type epoxy resin monomer, and the content of biphenyl in the epoxy resin composition is 31 wt % or more.
Meanwhile, when a resin composition is formed into a resin film having a thickness sufficient to encapsulate a semiconductor chip, there are cases where a crack develops in the resin film during handling. This problem is likely to arise particularly when a thermosetting resin that allows easily achieving high heat resistance is used or when an inorganic filler that contributes to low thermal expansivity is used. To solve the problem, improving flexibility of the resin composition used for forming a resin film is considered to be effective. The phrase “flexibility of a resin composition” in the present specification means, when the resin composition contains an organic solvent or the like and is in a liquid state, flexibility of the resin composition solidified at room temperature (25° C.) by drying the organic solvent.
As a method for improving flexibility of a resin composition in a solid state, a method of causing such a small amount of an organic solvent that allows maintaining the solid state to be contained in the resin composition is conceivable. However, during heating and curing of the resin composition containing the small amount of the organic solvent, volatilization of the organic solvent may develop a void in a cured product or roughen the surface of the cured product. Since the organic solvent volatilizes during heating and curing, a need for creating a safer work environment also arises. The thicker the resin film is, the more significant these problems become, and therefore improvement is desired.
In recent years, insulating materials used in electronic parts are required to have dielectric properties that allow reducing transmission loss of high-frequency signals or, in other words, a low relative dielectric constant and a low dielectric loss tangent; in line with this, low-polarity components have become widely used in resin compositions. However, there are tendencies that use of a low-polarity component weakens adhesion of a cured product of the resin composition; in particular, when the resin composition is used in semiconductor chip encapsulation, backside protection, and the like, a problem that sufficient adhesion to a material, such as a semiconductor chip or a semiconductor wafer, processed from a silicon wafer cannot be obtained has arisen.
In view of the circumstances, an object of the embodiment is to provide a resin composition that, while being excellent in flexibility in a solid state, can suppress generation of a volatile component during heating and curing and yields a cured product having excellent adhesion to a silicon wafer, as well as a resin film, a printed wiring board, and a semiconductor package, in each of which the resin composition is used.
The present inventors have conducted studies to solve the aforementioned problems, and as a result found that the problems can be solved by the following embodiment.
Specifically, the embodiment relates to [1] to below.
The embodiment can provide a resin composition that, while being excellent in flexibility in a solid state, can suppress generation of a volatile component during heating and curing and forms a cured product having excellent adhesion to a silicon wafer, as well as a resin film, a printed wiring board, and a semiconductor package, in each of which the resin composition is used.
In the present specification, a numerical value range expressed using “to” indicates a range including the numerical values placed before and after “to” as the minimum value and the maximum value, respectively.
For example, the notation of a numerical value range “X to Y” (X and Y are real numbers) means the numerical value range of X or more and Y or less. The phrase “X or more” in the present specification means X and numerical values greater than X. The phrase “Y or less” in the present specification means Y and numerical values smaller than Y.
The lower limit value and the upper limit value of a numerical value range described in the present specification are each appropriately combined with the lower limit value or the upper limit value of another numerical value range.
In a numerical value range described in the present specification, the lower limit value or the upper limit value of the numerical value range may be replaced by a value shown in Examples.
Each of components and materials exemplified in the present specification may be used alone, or may be used in combination of two or more types unless otherwise specified.
In the present specification, the content of each component in a resin composition means, when there are a plurality of substances corresponding to the component in the resin composition, a total amount of the plurality of substances present in the resin composition unless otherwise specified.
In the present specification, a “resin composition” means a mixture of two or more components containing at least a resin and, when the resin is a thermosetting resin, also encompasses the mixture cured to B-stage. It should be noted that the type and content of each component in the resin composition in B-stage means the type and content of the component before cured to B-stage, that is, the type and blending amount of the component blended to produce the resin composition.
In the present specification, “solid content” means components other than solvents and encompasses those in a liquid state, a starch-syrup-like state, and a waxy state at room temperature. The room temperature in the present specification indicates 25° C. In the present specification, “(meth)acrylate” means “acrylate” and “methacrylate” corresponding to it. Similarly, “(meth)acryl” means “acryl” and “methacryl” corresponding to it, and “(meth)acryloyl” means “acryloyl” and “methacryloyl” corresponding to it.
In the present specification, “molecular weight” of a compound means, when the compound is not a polymer and has a structural formula that can be specified, a molecular weight that can be calculated from the structural formula; when the compound is a polymer, it means a number average molecular weight.
A number average molecular weight in the present specification means a value measured as a polystyrene-equivalent value by gel permeation chromatography (GPC). Specifically, a number average molecular weight in the present specification can be measured by the method described in Examples.
The action mechanism described in the present specification is conjecture, and does not limit a mechanism that achieves the effect of the resin composition according to the embodiment.
The embodiment also encompasses aspects in which matters described in the present specification are combined as appropriate.
A resin composition of the embodiment is a resin composition including:
In the present specification, the components may be abbreviated as the component (A), the component (B), etc., and other components may also be abbreviated similarly.
The compound (B) that is in a liquid state at 25° C., has a reactive group, and has a molecular weight of 1,000 or less may be referred to as “reactive liquid compound (B).”
Each component that may be contained in the resin composition of the embodiment is described below in turn.
In the embodiment, being in a liquid state at 25° C. means that a viscosity obtained with the following measurement method is 100,000 mPa·s or less.
In the present specification, a viscosity at 25° C. means the viscosity measured using the aforementioned method.
The reason why the resin composition of the embodiment can form a cured product having excellent adhesion to a silicon wafer and, while being excellent in flexibility, can suppress generation of a volatile component during heating and curing is presumed as follows.
The resin composition of the embodiment contains a compound that is in a liquid state at 25° C. and has a molecular weight of 1,000 or less (B) as a component that improves flexibility of the resin composition. Since the reactive liquid compound (B) is a liquid component having a relatively low molecular weight, it can be considered that the reactive liquid compound (B) can properly enter between resin component molecules and effectively weaken the interaction between the resin component molecules, thereby improving flexibility of the resin composition.
In addition, since the reactive liquid compound (B) has a reactive group, the reactive liquid compound (B) can react with the reactive liquid compound (B) or other component during heating and curing of the thermosetting resin (A). That is, the reactive liquid compound (B) suppresses volatilization by its curing reaction while simultaneously contributing to improvement in flexibility. Therefore, it can be considered that the resin composition of the embodiment can improve flexibility while simultaneously suppressing generation of a volatile component, as compared with a case where an organic solvent or the like is used as a component for improving flexibility.
Furthermore, it is presumed that by virtue of containing the silane coupling agent (D), the resin composition of the embodiment is enhanced in its adhesive interface between the cured product of the resin composition and a silicon wafer, resulting in improvement in adhesion to the silicon wafer.
Each component that may be contained in the resin composition of the embodiment is described below in turn.
The resin composition of the embodiment contains the thermosetting resin (A).
The thermosetting resin (A) may be used alone, or may be used in combination of two or more types.
Examples of the thermosetting resin (A) include an epoxy resin, a phenol resin, a maleimide resin, a cyanate resin, an isocyanate resin, a benzoxazine resin, an oxetane resin, an amino resin, an unsaturated polyester resin, an allyl resin, a dicyclopentadiene resin, a silicone resin, a triazine resin, and a melamine resin.
Among them, from the viewpoint of heat resistance, the thermosetting resin (A) is preferably a maleimide resin, and more preferably one or more selected from the group consisting of a maleimide resin having one or more N-substituted maleimide groups and a derivative of the maleimide resin.
In the following description, “one or more selected from the group consisting of a maleimide resin having one or more N-substituted maleimide groups and a derivative of the maleimide resin” may be referred to as “maleimide-based resin.”
In the following description, a maleimide resin having one or more N-substituted maleimide groups may be referred to as “maleimide resin (AX)” or “component (AX).”
A derivative of a maleimide resin having one or more N-substituted maleimide groups may be referred to as “maleimide resin derivative (AY)” or “component (AY).”
The maleimide resin (AX) is not particularly limited as long as it is a maleimide resin having one or more N-substituted maleimide groups.
From the viewpoint of conductor adhesion properties and heat resistance, the maleimide resin (AX) is preferably an aromatic maleimide resin having two or more N-substituted maleimide groups, and more preferably an aromatic bismaleimide resin having two N-substituted maleimide groups.
In the present specification, an “aromatic maleimide resin” means a compound having an N-substituted maleimide group directly bonded to an aromatic ring. In the present specification, an “aromatic bismaleimide resin” means a compound having two N-substituted maleimide groups directly bonded to an aromatic ring. In the present specification, an “aromatic polymaleimide resin” means a compound having three or more N-substituted maleimide groups directly bonded to an aromatic ring.
In the present specification, an “aliphatic maleimide resin” means a compound having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon.
From the viewpoint of dielectric properties, conductor adhesion properties, and heat resistance, the maleimide resin (AX) is preferably a maleimide resin containing a condensed ring of an aromatic ring and an aliphatic ring in a molecular structure and having two or more N-substituted maleimide groups [hereinafter sometimes referred to as “maleimide resin (A1)” or “component (A1).”].
From the viewpoint of dielectric properties, conductor adhesion properties, and heat resistance, the maleimide resin (A1) is preferably an aromatic maleimide resin containing a condensed ring of an aromatic ring and an aliphatic ring in a molecular structure and having two or more N-substituted maleimide groups.
The maleimide resin (A1) is more preferably an aromatic bismaleimide resin containing a condensed ring of an aromatic ring and an aliphatic ring in a molecular structure and having two N-substituted maleimide groups.
From the viewpoint of dielectric properties, conductor adhesion properties, and ease of manufacture, the condensed ring in the maleimide resin (A1) preferably has a condensed bicyclic structure, and more preferably is an indane ring.
The maleimide resin (A1) containing an indane ring is preferably an aromatic bismaleimide resin containing an indane ring.
In the present specification, an indane ring means a condensed bicyclic structure of an aromatic six-membered ring and a saturated aliphatic five-membered ring. At least one carbon atom among the ring-forming carbon atoms that form the indane ring has a bonding group for bonding to another group constituting the maleimide resin (A1). The ring-forming carbon atom having the bonding group and the other ring-forming carbon atoms need not to have, in addition the aforementioned bonding group, a bonding group, a substituent, or the like, but preferably have a bonding group other than the aforementioned bonding group to thereby form a divalent group.
In the maleimide resin (A1), the indane ring is preferably contained as a divalent group represented by the following general formula (A1-1).
wherein Ra1 is an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxy group, or a mercapto group; na1 is an integer of 0 to 3; Ra2 to Ra4 are each independently an alkyl group having 1 to 10 carbon atoms; and * represents a bonding site.
Examples of the alkyl group having 1 to 10 carbon atoms represented by Ra1 in the general formula (A1-1) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. These alkyl groups may be linear or branched.
Examples of the alkyl group contained in the alkyloxy group having 1 to 10 carbon atoms and the alkylthio group having 1 to 10 carbon atoms represented by Ra1 are the same as those of the alkyl group having 1 to 10 carbon atoms mentioned above.
Examples of the aryl group having 6 to 10 carbon atoms represented by Ra1 include a phenyl group and a naphthyl group.
Examples of the aryl group contained in the aryloxy group having 6 to 10 carbon atoms and the arylthio group having 6 to 10 carbon atoms represented by Ra1 are the same as those of the aryl group having 6 to 10 carbon atoms mentioned above.
Examples of the cycloalkyl group having 3 to 10 carbon atoms represented by Ra1 include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group.
When na1 in the general formula (A1-1) is an integer of 1 to 3, from the viewpoint of solvent solubility and reactivity, Ra1 is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.
Examples of the alkyl group having 1 to 10 carbon atoms represented by Ra2 to Ra4 are the same as those of Ra1 mentioned above. Among them, Ra2 to Ra4 are each preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
In the general formula (A1-1), na1 is an integer of 0 to 3 and, when na1 is 2 or 3, a plurality of Ra1s may be the same as or different from each other.
Among the foregoing, from the viewpoint of ease of manufacture, the divalent group represented by the general formula (A1-1) is preferably a divalent group represented by the following general formula (A1-1a) in which na1 is 0 and Ra2 to Ra4 are methyl groups, and more preferably a divalent group represented by the following general formula (A1-1a′) or a divalent group represented by the following general formula (A1-1a″).
wherein * represents a bonding site.
From the viewpoint of dielectric properties, conductor adhesion properties, heat resistance, and ease of manufacture, the maleimide resin (A1) containing the divalent group represented by the general formula (A1-1) is preferably one represented by the following general formula (A1-2).
wherein Ra1s to Ra4 and na1s are the same as those in the general formula (A1-1); Ra5s are each independently an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxy group, or a mercapto group; na2s are each independently an integer of 0 to 4; and na3 is a number of 0.95 to 10.0.
In the general formula (A1-2), a plurality of Ra1s, a plurality of na1s, a plurality of Ra5s, and a plurality of na2s may each be the same as or different from each other.
When na3 is more than 1, a plurality of Ra2s, a plurality of Ra3s, and a plurality of Ra4s may each be the same as or different from each other.
Examples of the alkyl group having 1 to 10 carbon atoms, the alkyloxy group having 1 to 10 carbon atoms, the alkylthio group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxy group having 6 to 10 carbon atoms, the arylthio group having 6 to 10 carbon atoms, and the cycloalkyl group having 3 to 10 carbon atoms represented by Ra5 in the general formula (A1-2) are the same as those of Ra1 mentioned above, and the same applies to preferred examples.
In the general formula (A1-2), na2 is an integer of 0 to 4, and from the viewpoint of compatibility with other resins, dielectric properties, conductor adhesion properties, and ease of manufacture, preferably an integer of 1 to 3, more preferably 2 or 3, and further preferably 2.
When na2 is 1 or more, a benzene ring and an N-substituted maleimide group form a staggered conformation, and solvent solubility tends to be further improved by suppression of intermolecular stacking. When na2 is 1 or more, from the viewpoint of suppression of intermolecular stacking, the substitution position of Ra5 is preferably an ortho position with respect to the N-substituted maleimide group.
From the viewpoint of dielectric properties, conductor adhesion properties, solvent solubility, ease of handling, and heat resistance, na3 in the general formula (A1-2) is preferably a number of 0.98 to 8.0, more preferably a number of 1.0 to 7.0, and further preferably a number of 1.1 to 6.0. Meanwhile, na3 represents the average number of structural units each containing an indane ring.
From the viewpoint of dielectric properties, conductor adhesion properties, solvent solubility, and ease of manufacture, the maleimide resin (A1) represented by the general formula (A1-2) is more preferably one represented by the following general formula (A1-3) or one represented by the following general formula (A1-4).
wherein Ra1s to Ra5s, na1s, and na3 are the same as those in the general formula (A1-2).
wherein Ra1s to Ra4, na1s, and na3 are the same as those in the general formula (A1-2). Examples of the maleimide resin (A1) represented by the general formula (A1-3) include a maleimide resin represented by the following general formula (A1-3-1), a maleimide resin represented by the following general formula (A1-3-2), and a maleimide resin represented by the following general formula (A1-3-3).
wherein na3 is the same as that in the general formula (A1-2).
From the viewpoint of dielectric properties, conductor adhesion properties, solvent solubility, and ease of manufacture, the maleimide resin (A1) represented by the general formula (A1-4) is more preferably one represented by the following general formula (A1-4-1).
wherein na3 is the same as that in the general formula (A1-2).
The number average molecular weight of the maleimide resin (A1) is not particularly limited, but from the viewpoint of compatibility with other resins, conductor adhesion properties, and heat resistance, it is preferably 600 to 3,000, more preferably 800 to 2,000, and further preferably 1,000 to 1,500.
The maleimide resin (AX) may be a maleimide resin (A2) [hereinafter sometimes referred to as “maleimide resin (A2)” or “component (A2).”] other than the maleimide resin (A1) mentioned above.
The maleimide resin (A2) is preferably a maleimide resin represented by the following general formula (A2-1).
wherein Xa11 is a divalent organic group containing no condensed ring of an aromatic ring and an aliphatic ring.
Xa11 in the general formula (A2-1) is a divalent organic group containing no condensed ring of an aromatic ring and an aliphatic ring.
Examples of the divalent organic group represented by Xa11 in the general formula (A2-1) include a divalent group represented by the following general formula (A2-2), a divalent group represented by the following general formula (A2-3), a divalent group represented by the following general formula (A2-4), a divalent group represented by the following general formula (A2-5), and a divalent group represented by the following general formula (A2-6).
wherein Ra11 is an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom; na11 is an integer of 0 to 4; and * represents a bonding site.
Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by Ra11 in the general formula (A2-2) include an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a t-butyl group, or a n-pentyl group; an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms. The aliphatic hydrocarbon group having 1 to 5 carbon atoms may be linear or branched. The aliphatic hydrocarbon group having 1 to 5 carbon atoms is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and further preferably a methyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In the general formula (A2-2), na11 is an integer of 0 to 4 and, from the viewpoint of availability, preferably an integer of 0 to 2, more preferably 0 or 1, and further preferably 0.
When na11 is an integer of 2 or more, a plurality of Ra11s may be the same as or different from each other.
wherein Ra12 and Ra13 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom; Xa12 is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, a single bond, or a divalent group represented by the following general formula (A2-3-1); na12 and na13 are each independently an integer of 0 to 4; and * represents a bonding site.
Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by Ra12 and Ra13 in the general formula (A2-3) are the same as those of Ra11 mentioned above.
Examples of the alkylene group having 1 to 5 carbon atoms represented by Xa12 in the general formula (A2-3) include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group. Examples of the alkylidene group having 2 to 5 carbon atoms represented by Xa12 in the general formula (A2-3) include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group.
In the general formula (A2-3), na12 and na13 are each independently an integer of 0 to 4 and, from the viewpoint of availability, compatibility with other resins, and suppression of gelation of a product during the reaction, preferably an integer of 1 to 3, more preferably 1 or 2, and further preferably 2.
When na12 or na13 is an integer of 2 or more, a plurality of Ra12s or a plurality of Ra13s may each be the same as or different from each other.
The divalent group represented by the general formula (A2-3-1), which is represented by Xa12 in the general formula (A2-3), is as follows.
wherein Ra14 and Ra15 are each independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom; Xa13 is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond; na14 and na15 are each independently an integer of 0 to 4; and * represents a bonding site.
Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by Ra14 and Ra15 in the general formula (A2-3-1) are the same as those of Ra11 mentioned above.
Examples of the alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms represented by Xa13 in the general formula (A2-3-1) are the same as those of Xa12 mentioned above.
In the general formula (A2-3-1), na14 and na15 are each independently an integer of 0 to 4 and, from the viewpoint of availability, preferably an integer of 0 to 2, more preferably 0 or 1, and further preferably 0.
When na14 or na15 is an integer of 2 or more, a plurality of Ra14s or a plurality of Ra15s may be the same as or different from each other.
wherein na16 is an integer of 0 to 10; and * represents a bonding site.
From the viewpoint of availability, na16 in the general formula (A2-4) is preferably an integer of 0 to 5, more preferably an integer of 0 to 4, and further preferably an integer of 0 to 3.
wherein na17 is a number of 0 to 5; and * represents a bonding site.
wherein Ra16 and Ra17 are each independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms; na18 is an integer of 1 to 8; and * represents a bonding site.
Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by Ra16 and Ra17 in the general formula (A2-6) are the same as those of Ra11 mentioned above.
In the general formula (A2-6), na18 is an integer of 1 to 8, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and further preferably 1. When na18 is an integer of 2 or more, a plurality of Ra16s or a plurality of Ra17s may each be the same as or different from each other.
The maleimide resin (A2) is preferably a polymaleimide resin represented by the following general formula (A2-7).
wherein Xa14s are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms; and na19 is an integer of 2 to 5.
Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by Xa14 in the general formula (A2-7) include a divalent aliphatic hydrocarbon group such as an alkylene group having 1 to 5 carbon atoms or an alkylidene group having 2 to 5 carbon atoms; and a divalent hydrocarbon group including an aromatic hydrocarbon group represented by the following general formula (A2-8).
Examples of the alkylene group having 1 to 5 carbon atoms include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group. The alkylene group having 1 to 5 carbon atoms is preferably an alkylene group having 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and further preferably a methylene group.
The alkylidene group having 2 to 5 carbon atoms is preferably an alkylidene group having 2 to 4 carbon atoms, more preferably an alkylidene group having 2 or 3 carbon atoms, and further preferably an isopropylidene group.
[Chem. 15]
*—Xa15—Ara1—Xa16—* (A2-8)
wherein Ara1 is a divalent aromatic hydrocarbon group; Xa15 and Xa16 are each independently a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms; and * represents a bonding site.
Examples of the divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by Xa15 and Xa16 in the general formula (A2-8) include an alkylene group having 1 to 5 carbon atoms and an alkylidene group having 2 to 5 carbon atoms and are the same as those of Xa14 in the general formula (A2-7). Among them, a methylene group is preferred.
Examples of the divalent aromatic hydrocarbon group represented by Ara1 in the general formula (A2-8) include a phenylene group, a naphthylene group, a biphenylene group, and an anthranylene group. Among them, a biphenylene group is preferred. Examples of the biphenylene group include a 4,2′-biphenylene group, a 4,3′-biphenylene group, a 4,4′-biphenylene group, and a 3,3′-biphenylene group; among them, a 4,4′-biphenylene group is preferred.
Among the above options, Xa14 in the general formula (A2-7) is preferably a divalent hydrocarbon group including an aromatic hydrocarbon group represented by the general formula (A2-8), and more preferably a divalent hydrocarbon group represented by the general formula (A2-8) in which Xa15 and Xa16 are methylene groups and Aral is a 4,4′-biphenylene group.
In the general formula (A2-7), na19 is an integer of 2 to 5, preferably an integer of 2 to 4, and more preferably 2 or 3.
Examples of the maleimide resin (A2) include an aromatic bismaleimide resin, an aromatic polymaleimide resin, and an aliphatic maleimide resin.
Specific examples of the maleimide resin (A2) include, for example, bis(4-maleimidophenyl) methane, polyphenylmethane maleimide, m-phenylenebismaleimide, 2,2-bis [4-(4-maleimidophenoxy)phenyl]propane, 4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, polyphenylmethanemaleimide, and biphenyl aralkyl-based maleimide. Among them, biphenyl aralkyl-based maleimide is preferred.
The maleimide resin derivative (AY) is preferably an aminomaleimide resin having a structural unit derived from the maleimide resin (AX) mentioned above and a structural unit derived from a diamine compound.
The aminomaleimide resin has a structural unit derived from the maleimide resin (AX) and a structural unit derived from a diamine compound.
The aminomaleimide resin is obtained by, for example, allowing Michael addition to occur between the maleimide resin (AX) and a diamine compound.
Examples of the diamine compound that can be used are the same amine compounds each having at least two primary amino groups in one molecule as those mentioned in JP 2020-200406 A. Among them, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-4,4′-diaminodiphenylmethane, 2,2-bis [4-(4-aminophenoxy)phenyl]propane, 4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline, 4,4′-[1,4-phenylenebis(1-methylethylidene]bisaniline, and 3,3′-diethyl-4,4′-diaminodiphenylmethane are preferred.
The thermosetting resin (A) preferably has a viscosity at 25° C. measured by the aforementioned method of more than 100,000 mPa·s, and more preferably is in a solid state at 25° C.
In the resin composition of the embodiment, the content of the thermosetting resin (A) is not particularly limited, but it is preferably 5 to 60 mass %, more preferably 8 to 40 mass %, further preferably 10 to 30 mass %, and particularly preferably 15 to 25 mass %, relative to the total amount (100 mass %) of resin components in the resin composition of the embodiment.
When the content of the thermosetting resin (A) is equal to or more than the lower limit value, heat resistance, formability, processability, and conductor adhesion properties tend to be improved. When the content of the thermosetting resin (A) is equal to or less than the upper limit value, dielectric properties tend to be improved.
The upper limit value of the content of the thermosetting resin (A) may be 80 mass % or less, 70 mass % or less, or 60 mass % or less, relative to the total amount (100 mass %) of the thermosetting resin (A) and the reactive liquid compound (B). The lower limit value of the content of the thermosetting resin (A) may be 5 mass % or more, 10 mass % or more, or 15 mass % or more, relative to the total amount (100 mass %) of the thermosetting resin (A) and the reactive liquid compound (B).
In the present specification, a “resin component” means a resin and a compound that forms a resin by a curing reaction.
In the resin composition of the embodiment, for example, the component (A) and the component (B) correspond to resin components.
When the resin composition of the embodiment contains, in addition to the aforementioned components, a resin or a compound that forms a resin through a curing reaction as an optional component, the optional component is also included in the resin components. Examples of the optional component corresponding to a resin component include a component (E), a component (F), and the like described later.
On the other hand, the component (C) and the component (D) are not included in the resin components.
The content of the resin components in the resin composition of the embodiment is not particularly limited, but from the viewpoint of low thermal expansivity, heat resistance, flame retardance, and conductor adhesion properties, it is preferably 5 to 80 mass %, more preferably 10 to 60 mass %, and further preferably 20 to 40 mass %, relative to the total solid content (100 mass %) of the resin composition of the embodiment.
The content of the maleimide-based resin in the thermosetting resin (A) is not particularly limited, but it is preferably 80 to 100 mass %, more preferably 90 to 100 mass %, and further preferably 95 to 100 mass %, relative to the total amount (100 mass %) of the thermosetting resin (A).
When the content of the maleimide-based resin is equal to or more than the lower limit value, heat resistance, formability, processability, and conductor adhesion properties tend to be improved. When the content of the maleimide-based resin is equal to or less than the upper limit value, dielectric properties tend to be improved.
The reactive liquid compound (B) is not particularly limited as long as it is a compound that is in a liquid state at 25° C., has a reactive group, and has a molecular weight of 1,000 or less. It should be noted that, in the embodiment, the silane coupling agent is not encompassed in the concept of the reactive liquid compound (B).
The reactive liquid compound (B) may be used alone, or may be used in combination of two or more types.
The reactive liquid compound (B) preferably has two or more reactive groups, more preferably two to five reactive groups, further preferably two to four reactive groups, and particularly preferably two or three reactive groups in one molecule.
When the number of reactive groups falls within the aforementioned range, excellent flexibility tends to be easily achieved and simultaneously volatilization during heating and curing is effectively suppressed.
The molecular weight of the reactive liquid compound (B) is 1,000 or less, preferably 100 to 800, more preferably 150 to 600, and further preferably 200 to 400.
When the molecular weight of the reactive liquid compound (B) is equal to or more than the lower limit value, volatilization of the reactive liquid compound (B) before the resin composition is heated and cured tends to be easily suppressed. When the molecular weight of the reactive liquid compound (B) is equal to or less than the upper limit value, more excellent flexibility tends to be easily achieved.
The viscosity at 25° C. of the reactive liquid compound (B) is preferably 1 to 5,000 mPa·s, more preferably 2 to 1,000 mPa·s, and further preferably 4 to 500 mPa·s.
When the viscosity at 25° C. of the reactive liquid compound (B) is equal to or more than the lower limit value, volatilization of the reactive liquid compound (B) tends to be easily suppressed. When the viscosity at 25° C. of the reactive liquid compound (B) is equal to or less than the upper limit value, more excellent flexibility tends to be easily achieved.
The viscosity at 25° C. of the reactive liquid compound (B) can be measured by the measurement method mentioned above.
The reactive liquid compound (B) preferably has, as the reactive group, one or more selected from a functional group having an ethylenically unsaturated bond, an epoxy group, a hydroxy group, a carboxy group, and an amino group.
In the present specification, an “ethylenically unsaturated bond” means a carbon-carbon double bond to which addition reaction can be made, and does not include an aromatic ring double bond.
Examples of the functional group having an ethylenically unsaturated bond include a vinyl group, an allyl group, a 1-methylallyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a styryl group, an N-substituted maleimide group, and a (meth)acryloyl group.
Among them, the reactive group is more preferably a functional group having an ethylenically unsaturated bond or an epoxy group, further preferably, from the viewpoint of easily achieving more excellent dielectric properties, a functional group having an ethylenically unsaturated bond, and particularly preferably a (meth)acryloyl group.
Specific examples of the reactive liquid compound (B) having, as the reactive group, a (meth)acryloyl group include a (meth)acrylate such as a mono(meth)acrylate, a di(meth)acrylate, or a (meth)acrylate having three or more functional groups.
Examples of the mono(meth)acrylate include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, isooctyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, dodecyl(meth)acrylate, lauryl(meth)acrylate, tridecyl(meth)acrylate, stearyl(meth)acrylate, cyclohexyl(meth)acrylate, cyclopentyl(meth)acrylate, benzyl(meth)acrylate, dicyclopentenyl(meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate, methoxyethyl(meth)acrylate, ethoxyethyl(meth)acrylate, butoxyethyl(meth)acrylate, phenoxyethyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and 4-hydroxybutyl (meth)acrylate.
Examples of the di(meth)acrylate include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, tricyclodecane di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, and dioxane glycol di(meth)acrylate.
Examples of dioxane glycol di(meth)acrylate include 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxan-2-yl]-2,2-dimethylethyl acrylate.
Examples of the (meth)acrylate having three or more functional groups include trimethylolpropane tri(meth)acrylate, pentaethritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.
Among the options mentioned above, the (meth)acrylate is preferably a di(meth)acrylate.
The di(meth)acrylate is preferably a diacrylate represented by the following general formula (B-1) or a dimethacrylate represented by the following general formula (B-2), and more preferably a dimethacrylate represented by the following general formula (B-2).
wherein Rb1 is an alkylene group having 1 to 20 carbon atoms.
From the viewpoint of flexibility and volatilization suppression, the number of carbon atoms in the alkylene group having 1 to 20 carbon atoms represented by Rb1 in the general formulae (B-1) and (B-2) is preferably 4 to 18, more preferably 6 to 15, and further preferably 8 to 12.
Examples of the alkylene group having 1 to 20 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tetradecylene group, and a pentadecylene group. The alkylene group may be linear, branched, or cyclic, and preferably is linear.
In the resin composition of the present embodiment, the content of the reactive liquid compound (B) is not particularly limited, but it is preferably 5 to 60 mass %, more preferably 8 to 40 mass %, further preferably 10 to 30 mass %, and particularly preferably 15 to 25 mass %, relative to the total amount (100 mass %) of the resin components in the resin composition of the embodiment.
In the resin composition of the present embodiment, the content of the reactive liquid compound (B) is not particularly limited, but it is preferably 0.5 to 20 mass %, more preferably 1.0 to 15 mass %, and further preferably 1.5 to 10 mass %, relative to the total solid content (100 mass %) of the resin composition.
When the content of the reactive liquid compound (B) is equal to or more than the lower limit value, more excellent flexibility tends to be easily achieved. When the content of the reactive liquid compound (B) is equal to or less than the upper limit value, generation of a volatile component during heating and curing tends to be easily suppressed.
By virtue of containing the inorganic filler (C), the resin composition of the embodiment is likely to easily achieve more excellent low thermal expansivity, heat resistance, and flame retardance.
In particular, since the resin composition of the embodiment is excellent in flexibility, it is possible to further improve low thermal expansivity by increasing the content of the inorganic filler (C).
The inorganic filler (C) may be used alone, or may be used in combination of two or more types.
Examples of the inorganic filler (C) include silica, alumina, titanium oxide, mica, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay, talc, aluminum borate, and silicon carbide. Among them, from the viewpoint of low thermal expansivity, heat resistance, and flame retardance, silica, alumina, mica, and talc are preferred, and silica and alumina are more preferred.
Examples of the silica include precipitated silica produced by a wet process and having a high moisture content and dry process silica produced by a dry process and containing little bound water. Specific examples of the dry process silica include crushed silica, fumed silica, and molten silica, which vary in production method.
From the viewpoint of improving dispersibility and adhesion to organic components, the inorganic filler (C) may have been surface-treated with a surface treatment agent such as a silane coupling agent.
The mean particle diameter of the inorganic filler (C) is not particularly limited, but from the viewpoint of dispersibility of the inorganic filler (C) and fine patternability, it is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, further preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm.
In the present specification, the mean particle diameter of the inorganic filler (C) is a particle diameter of a point corresponding to 50% by volume on a distribution curve of particle diameter cumulative frequencies where the total volume of particles is 100%. The mean particle diameter of the inorganic filler (C) can be measured with, for example, a particle size distribution measuring device using a laser diffraction scattering method.
The inorganic filler (C) has a spherical shape or a crushed shape, for example, and preferably a spherical shape.
In the resin composition of the embodiment, the content of the inorganic filler (C) is not particularly limited, but it is preferably 20 to 95 mass %, more preferably 40 to 90 mass %, and further preferably 60 to 80 mass %, relative to the total solid content (100 mass %) of the resin composition.
When the content of the inorganic filler (C) is equal to or more than the lower limit value, low thermal expansivity, heat resistance, and flame retardance tend to be easily improved. When the content of the inorganic filler (C) is equal to or less than the upper limit value, formability and conductor adhesion properties tend to be easily improved.
By virtue of containing the silane coupling agent (D), the resin composition of the embodiment can yield a cured product that is excellent in adhesion to a silicon wafer.
The silane coupling agent (D) may be used alone, or may be used in combination of two or more types.
The silane coupling agent (D) is preferably a compound having a hydrolyzable group directly bonded to a silicon atom and a reactive organic group directly bonded to the silicon atom.
The hydrolyzable group is preferably an alkoxy group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.
When the silane coupling agent (D) has an alkoxy group, the number of the alkoxy groups is not particularly limited, but it is preferably 1 to 3, more preferably 2 or 3, and further preferably 3. In short, the silane coupling agent (D) is preferably trialkoxysilane.
The reactive organic group is an organic group having a reactive group.
Examples of the reactive group in the reactive organic group include an epoxy group, an amino group, a mercapto group, an isocyanate group, and a functional group having an ethylenically unsaturated bond. Among them, from the viewpoint of adhesion to a silicon wafer, a functional group having an ethylenically unsaturated bond is preferred. In other words, the silane coupling agent (D) preferably has a functional group having an ethylenically unsaturated bond.
Examples of the functional group having an ethylenically unsaturated bond include a vinyl group, a 1-methylallyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a styryl group, an N-substituted maleimide group, and a (meth)acryloyl group. Among them, from the viewpoint of the dielectric properties and low thermal expansivity, a vinyl group and a (meth)acryloyl group are preferred.
From the viewpoint of further enhancing adhesion between a cured product of the resin composition and a silicon wafer, the reactive group in the silane coupling agent (D) is preferably reactive with one or more selected from the group consisting of the component (A) and the component (B), and more preferably reactive with both the component (A) and the component (B). From this viewpoint, each of the reactive group in the component (A), the reactive group in the component (B), and the reactive group in the component (D) is preferably a functional group having an ethylenically unsaturated bond. In this case, the component (A), the component (B), and the component (D) can react with each other by radical polymerization to achieve further improvement in adhesion to a silicon wafer.
When the reactive group in the silane coupling agent (D) is one that can directly bond to a silicon atom, it may be directly bonded to the silicon atom. In this case, the reactive group corresponds to the reactive organic group. Alternatively, the reactive group may be indirectly bonded to the silicon atom as a substituent of the hydrocarbon group directly bonded to the silicon atom.
The hydrocarbon group that can have a reactive group as a substituent is preferably an alkyl group. The number of carbons in the hydrocarbon group is not particularly limited, but it is preferably 1 to 15, more preferably 2 to 12, and further preferably 3 to 10.
Examples of the silane coupling agent (D) include a silane coupling agent containing an amino group, such as γ-aminopropyltrimethoxysilane, aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, or N-phenyl-γ-aminopropyltriethoxysilane; a silane coupling agent containing a mercapto group, such as γ-mercaptopropyltrimethoxysilane or γ-mercaptopropyltriethoxysilane; a silane coupling agent containing an epoxy group, such as 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane; a silane coupling agent containing an isocyanate group, such as 3-isocyanatepropyltriethoxysilane; a silane coupling agent containing a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, or (7-octenyl)trimethoxysilane; and a silane coupling agent containing a (meth)acryloxy group, such as γ-methacryloxypropyltrimethoxysilane, γ-γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, methacryloxypropylmethyldiethoxysilane, γ-γ-acryloxypropyltrimethoxysilane, acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropylmethyldiethoxysilane, or 8-methacryloxyoctyltrimethoxysilane.
Among them, from the viewpoint of adhesion to a silicon wafer, a silane coupling agent containing a vinyl group and a silane coupling agent containing a (meth)acryloxy group are preferred, and 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, vinyltrimethoxysilane, and (7-octenyl)trimethoxysilane are more preferred.
In the resin composition of the present embodiment, the content of the silane coupling agent (D) is not particularly limited, but it is preferably 0.1 to 5 mass %, more preferably 0.5 to 3 mass %, and further preferably 0.8 to 1.5 mass %, relative to the total amount (100 mass %) of the resin components in the resin composition of the embodiment. When the content of the silane coupling agent (D) is equal to or more than the lower limit value, adhesion to a silicon wafer tends to be easily improved. When the content of the silane coupling agent (D) is equal to or less than the upper limit value, not only excellent cost efficiency is achieved but also the resin film is less likely to become tacky.
The resin composition of the embodiment preferably further contains the elastomer having a molecular weight of more than 1,000 (E) [hereinafter sometimes referred to as “elastomer (E).”].
When the resin composition of the embodiment contains the elastomer (E), more excellent dielectric properties tend to be easily achieved.
The “elastomer” used herein means a polymer having a glass transition temperature of 25° C. or lower measured by differential scanning calorimetry in accordance with JIS K 6240:2011.
The elastomer (E) may be used alone, or may be used in combination of two or more types.
The molecular weight of the elastomer (E) is more than 1,000, preferably 1,050 to 500,000, more preferably 1,100 to 350,000, and further preferably 1,150 to 200,000.
When the molecular weight of the elastomer (E) is equal to or more than the lower limit value, heat resistance and the like of the resulting resin composition tend to be easily kept favorably. When the molecular weight of the elastomer (E) is equal to or less than the upper limit value, dielectric properties and conductor adhesion properties of the resulting resin composition tend to be easily improved.
Preferred examples of the elastomer (E) include a conjugated diene polymer (E1), a modified conjugated diene polymer (E2), and a styrene-based elastomer (E3).
Hereinafter, preferred aspects of these components will be described.
In the present specification, a “conjugated diene polymer” means a polymer of conjugated diene compound.
When the resin composition of the embodiment contains the conjugated diene polymer (E1), more excellent dielectric properties tend to be easily achieved.
The conjugated diene polymer (E1) may be used alone, or may be used in combination of two or more types.
Examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene.
The conjugated diene polymer (E1) may be a polymer of one type of conjugated diene compounds or may be a copolymer of two or more types of conjugated diene compounds.
The conjugated diene polymer (E1) may be a copolymer of one or more types of conjugated diene compounds and monomers other than the one or more types of conjugated diene compounds.
When the conjugated diene polymer (E1) is a copolymer, its polymerization type is not particularly limited, and may be any one of random polymerization, block polymerization, and graft polymerization.
From the viewpoint of compatibility with other resins and dielectric properties, the conjugated diene polymer (E1) is preferably a conjugated diene polymer having a plurality of vinyl groups in side chains.
The number of vinyl groups in one molecule of the conjugated diene polymer (E1) is not particularly limited, but from the viewpoint of compatibility with other resins and dielectric properties, it is preferably 3 or more, more preferably 5 or more, and further preferably 10 or more.
The upper limit of the number of vinyl groups in one molecule of the conjugated diene polymer (E1) is not particularly limited, and may be 100 or less, 80 or less, or 60 or less.
Examples of the conjugated diene polymer (E1) include a polybutadiene having a 1,2-vinyl group, a butadiene-styrene copolymer having a 1,2-vinyl group, and a polyisoprene having a 1,2-vinyl group. Among them, from the viewpoint of dielectric properties and heat resistance, a polybutadiene having a 1,2-vinyl group and a butadiene-styrene copolymer having a 1,2-vinyl group are preferred, and a polybutadiene having a 1,2-vinyl group is more preferred. The polybutadiene having a 1,2-vinyl group is preferably a polybutadiene homopolymer having a 1,2-vinyl group.
The 1,2-vinyl group derived from butadiene in the conjugated diene polymer (E1) is a vinyl group contained in a butadiene-derived structural unit represented by the following formula (E1-1).
When the conjugated diene polymer (E1) is a polybutadiene having a 1,2-vinyl group, the content of the structural unit having a 1,2-vinyl group relative to all the structural units derived from butadiene constituting the polybutadiene [hereinafter sometimes referred to as “vinyl group content.”] is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, and heat resistance, it is preferably 50 mol % or more, more preferably 70 mol % or more, and further preferably 85 mol % or more. The upper limit of the vinyl group content is not particularly limited, and may be 100 mol % or less, 95 mol % or less, or 90 mol % or less. The structural unit having a 1,2-vinyl group is preferably the butadiene-derived structural unit represented by the formula (E1-1).
From the same viewpoint, the polybutadiene having a 1,2-vinyl group is preferably a 1,2-polybutadiene homopolymer.
The number average molecular weight of the conjugated diene polymer (E1) is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, and heat resistance, it is preferably 1,050 to 3,000, more preferably 1,100 to 2,000, and further preferably 1,150 to 1,500.
The modified conjugated diene polymer (E2) is a polymer obtained by modifying a conjugated diene polymer.
When the resin composition of the embodiment contains the modified conjugated diene polymer (E2), more excellent dielectric properties tend to be easily achieved while possessing favorable heat resistance and low thermal expansivity.
The modified conjugated diene polymer (E2) may be used alone, or may be used in combination of two or more types.
For example, when the thermosetting resin (A) contains a maleimide-based resin, from the viewpoint of compatibility with other resins, dielectric properties, and conductor adhesion properties, the modified conjugated diene polymer (E2) is preferably a modified conjugated diene polymer obtained by modifying a conjugated diene polymer having a vinyl group in a side chain (e1) [hereinafter sometimes referred to as “conjugated diene polymer (e1).”] with a maleimide resin having two or more N-substituted maleimide groups (e2) [hereinafter sometimes referred to as “maleimide resin (e2).”].
As the conjugated diene polymer (e1), for example, the conjugated diene polymer having a vinyl group in a side chain described as the conjugated diene polymer (E1) can be used; the same applies to preferred aspects.
The conjugated diene polymer (e1) may be used alone, or may be used in combination of two or more types.
As the maleimide resin (e2), for example, the maleimide resin having two or more N-substituted maleimide groups described as the maleimide resin (AX) can be used; the same applies to preferred aspects.
The maleimide resin (e2) may be used alone, or may be used in combination of two or more types.
The modified conjugated diene polymer (E2) preferably has, in a side chain, a substituent [hereinafter sometimes referred to as “substituent (x).”] obtained by a reaction between the vinyl group in the conjugated diene polymer (e1) and the N-substituted maleimide groups in the maleimide resin (e2).
From the viewpoint of compatibility with other resins, dielectric properties, low thermal expansivity, and heat resistance, the substituent (x) is preferably a group having a structure represented by the following general formula (E2-1) or (E2-2) as a structure derived from the maleimide resin (e2).
wherein Xe1 is a divalent group obtained by removing two N-substituted maleimide groups from the maleimide resin (e2); *e1 is a site at which the conjugated diene polymer (e1) bonds to a carbon atom derived from a vinyl group in a side chain; and *e2 is a site for bonding to another atom.
The modified conjugated diene polymer (E2) preferably has the substituent (x) and a vinyl group (y) in side chains.
To know the proportion of the substituent (x) in the modified conjugated diene polymer (E2), the ratio of vinyl groups modified with the maleimide resin (e2) to vinyl groups in the conjugated diene polymer (e1) [hereinafter sometimes referred to as “vinyl group modification rate.”] can be used as an index.
The vinyl group modification rate is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, low thermal expansivity, and heat resistance, it is preferably 20 to 70%, more preferably 30 to 60%, and further preferably 35 to 50%. The vinyl group modification rate used herein is a value obtained by the method described in Examples.
The vinyl group (y) is preferably a 1,2-vinyl group in a butadiene-derived structural unit.
The number average molecular weight of the modified conjugated diene polymer (E2) is not particularly limited, but from the viewpoint of compatibility with other resins, dielectric properties, low thermal expansivity, and heat resistance, it is preferably 1,100 to 6,000, more preferably 1,300 to 4,000, and further preferably 1,500 to 2,000.
The modified conjugated diene polymer (E2) can be produced by allowing the conjugated diene polymer (e1) to react with the maleimide resin (e2).
A method for reacting the conjugated diene polymer (e1) with the maleimide resin (e2) is not particularly limited. For example, the modified conjugated diene polymer (E2) may be obtained by causing a reaction to occur by placing the conjugated diene polymer (e1), the maleimide resin (e2), a reaction catalyst, and an organic solvent in a reaction vessel and performing heating, keeping the temperature, stirring, and the like as necessary.
From the viewpoint of workability and suppression of gelation of a product during the reaction, the reaction temperature for the reaction is preferably 70 to 120° C., more preferably 80 to 110° C., and further preferably 85 to 105° C.
From the viewpoint of productivity and sufficient promotion of the reaction, the reaction time of the reaction is preferably 0.5 to 15 hours, more preferably 1 to 10 hours, and further preferably 3 to 7 hours.
It should be noted that these reaction conditions may be appropriately adjusted depending on the types of raw materials to use and the like, and are not particularly limited.
The ratio (Mm/Mv) of the number of moles (Mm) of the N-substituted maleimide group in the maleimide resin (e2) to the number of moles (Mv) of the side-chain vinyl group in the conjugated diene polymer (e1) in the reaction is not particularly limited, but from the viewpoint of compatibility of the resulting modified conjugated diene polymer (E2) with other resin and suppression of gelation of a product during the reaction, it is preferably 0.001 to 0.5, more preferably 0.005 to 0.1, and further preferably 0.008 to 0.05.
The styrene-based elastomer (E3) is not particularly limited as long as it is an elastomer having a styrene-based-compound-derived structural unit.
When the resin composition of the embodiment contains the styrene-based elastomer (E3), more excellent dielectric properties tend to be easily achieved.
The styrene-based elastomer (E3) may be used alone, or may be used in combination of two or more types.
The styrene-based elastomer (E3) preferably has a styrene-based-compound-derived structural unit represented by the following general formula (E3-1).
wherein Re1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; Re2 is an alkyl group having 1 to 5 carbon atoms; and ne1 is an integer of 0 to 5.
Examples of the alkyl group having 1 to 5 carbon atoms represented by Re1 and Re2 in the general formula (E3-1) include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a t-butyl group, and a n-pentyl group. The alkyl group having 1 to 5 carbon atoms may be linear or branched. Among them, an alkyl group having 1 to 3 carbon atoms is preferred, an alkyl group having 1 or 2 carbon atoms is more preferred, and a methyl group is further preferred.
In the general formula (E3-1), ne1 is an integer of 0 to 5, preferably an integer of 0 to 2, more preferably 0 or 1, and further preferably 0.
The styrene-based elastomer (E3) may contain a structural unit other than the styrene-based-compound-derived structural unit.
Examples of the structural unit other than styrene-based-compound-derived structural unit that may be contained in the styrene-based elastomer (E3) include a butadiene-derived structural unit, an isoprene-derived structural unit, a maleic-acid-derived structural unit, and a maleic-anhydride-derived structural unit.
The butadiene-derived structural unit and the isoprene-derived structural unit may be hydrogenated. When hydrogenated, the butadiene-derived structural unit is a structural unit in which an ethylene unit and a butylene unit are mixed, while the isoprene-derived structural unit is a structural unit in which an ethylene unit and a propylene unit are mixed.
Examples of the styrene-based elastomer (E3) include a hydrogenated styrene-butadiene-styrene block copolymer, a hydrogenated styrene-isoprene-styrene block copolymer, and a styrene maleic anhydride copolymer.
Examples of the hydrogenated styrene-butadiene-styrene block copolymer include SEBS where carbon-carbon double bonds in a butadiene block are completely hydrogenated and SBBS where the carbon-carbon double bond of 1,2-binding site in a butadiene block is partially hydrogenated. The complete hydrogenation in SEBS is typically 90% or more of all carbon-carbon double bonds; it may be 95% or more, 99% or more, or 100%. The partial hydrogenation rate in SBBS is, for example, 60 to 85% of all carbon-carbon double bonds. The hydrogenated styrene-isoprene-styrene block copolymer is obtained as SEPS where a polyisoprene block is hydrogenated.
Among them, from the viewpoint of dielectric properties, conductor adhesion properties, heat resistance, glass transition temperature, and low thermal expansivity, SEBS and SEPS are preferred, and SEBS is more preferred.
In the styrene-based elastomer (E3), the content of the styrene-based-compound-derived structural unit [hereinafter sometimes referred to as “styrene content.”] is not particularly limited, but it is preferably 5 to 60 mass %, more preferably 7 to 40 mass %, and further preferably 10 to 20 mass %.
The melt flow rate (MFR) of the styrene-based elastomer (E3) is not particularly limited, but under measurement conditions of 230° C. and a load of 2.16 kgf (21.2 N), it is preferably 0.1 to 20 g/10 min, more preferably 1 to 10 g/10 min, and further preferably 3 to 7 g/10 min.
The number average molecular weight of the styrene-based elastomer (E3) is not particularly limited, but it is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and further preferably 100,000 to 200,000.
Examples of the elastomer (E) other than the conjugated diene polymer (E1), the modified conjugated diene polymer (E2), and the styrene-based elastomer (E3) include a polyolefin resin, a polyphenylene ether resin, a polyester resin, a polyamide resin, and a polyacrylic resin other than these.
When the resin composition of the embodiment contains the elastomer (E), the content of the elastomer (E) is not particularly limited, but it is preferably 10 to 80 mass %, more preferably 30 to 70 mass %, and further preferably 50 to 60 mass %, relative to the total amount (100 mass %) of the resin components in the resin composition of the embodiment. When the content of the elastomer (E) is equal to or more than the lower limit value, more excellent dielectric properties tend to be easily achieved. When the content of the elastomer (E) is equal to or less than the upper limit value, more excellent heat resistance tends to be easily achieved.
The total content of one or more selected from the group consisting of the conjugated diene polymer (E1), the modified conjugated diene polymer (E2), and the styrene-based elastomer (E3) is not particularly limited, but from the viewpoint of dielectric properties and conductor adhesion properties, it is preferably 60 to 100 mass %, more preferably 80 to 100 mass %, and further preferably 90 to 100 mass %, relative to the total amount (100 mass %) of the elastomer (E).
From the viewpoint of dielectric properties and compatibility, the elastomer (E) preferably contains the styrene-based elastomer (E3) and one or more selected from the group consisting of the conjugated diene polymer (E1) and the modified conjugated diene polymer (E2).
When the elastomer (E) contains the styrene-based elastomer (E3) and one or more selected from the group consisting of the conjugated diene polymer (E1) and the modified conjugated diene polymer (E2), {[(E1)+ (E2)]/(E3)}, the ratio of the total content of the conjugated diene polymer (E1) and the modified conjugated diene polymer (E2) to the content of the styrene-based elastomer (E3), is not particularly limited, but from the viewpoint of dielectric properties and compatibility, it is preferably 0.1 to 5, more preferably 0.2 to 1, and further preferably 0.3 to 0.7.
The resin composition of the embodiment preferably further contains the curing accelerator (F).
When the resin composition of the embodiment contains the curing accelerator (F), more excellent dielectric properties, heat resistance, and conductor adhesion properties tend to be easily achieved.
The curing accelerator (F) may be used alone, or may be used in combination of two or more types.
From the viewpoint of efficiently forming chemical bonds of resin components during heating, the curing accelerator (F) preferably contains a radical polymerization initiator. The radical polymerization initiator acts as a polymerization initiator for radical polymerization, and is decomposed into species having unpaired electrons when exposed to energy such as light or heat. Examples of the radical polymerization initiator include organic peroxides, inorganic peroxides, and azo compounds described later, and an organic peroxide is preferred.
Examples of the curing accelerator (F) include an acid catalyst such as p-toluenesulfonic acid; an amine compound such as triethylamine, pyridine, tributylamine, or dicyandiamide; an imidazole compound such as methylimidazole, phenylimidazole, or 1-cyanoethyl-2-phenylimidazole; an isocyanate-masked imidazole compound such as an addition reaction product of a hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; a tertiary amine compound; a quaternary ammonium compound; a phosphorous-containing compound such as triphenyl phosphine; an organic peroxide such as dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy) hexine-3, 2,5-dimethyl-2,5-bis(t-butylperoxy) hexane, t-butylperoxy isopropyl monocarbonate, or 1,3-di(t-butylperoxy isopropyl)benzene; an inorganic peroxide such as potassium persulfate, sodium persulfate, or ammonium persulfate; an azo compound such as 2,2′-azobisisobutylonitrile, 2,2′-azobis(2,4-dimethylvaleronitrile), or 2,2′-azobis(4-methoxy-2′-dimethylvaleronitrile); and a carboxylic acid salt of manganese, cobalt, zinc, or the like.
Among them, from the viewpoint of a curing acceleration effect and storage stability, an imidazole compound, an isocyanate-masked imidazole compound, an organic peroxide, and a carboxylic acid salt are preferred, and an isocyanate-masked imidazole compound and an organic peroxide are more preferred.
When the resin composition of the embodiment contains the curing accelerator (F), the content of the curing accelerator (F) is not particularly limited, but it is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and further preferably 4 to 8 parts by mass, relative to the total amount (100 parts by mass) of the thermosetting resin (A) and the reactive liquid compound (B).
When the content of the curing accelerator (F) is equal to or more than the lower limit value, sufficient curing acceleration effect tends to be easily achieved. When the content of the curing accelerator (F) is equal to or less than the upper limit value, storage stability tends to be improved.
When the resin composition of the embodiment contains, as the curing accelerator (F), a radical polymerization initiator, the content of the radical polymerization initiator is not particularly limited, but it is preferably 0.05 to 7 parts by mass, more preferably 0.5 to 5 parts by mass, and further preferably 2 to 4 parts by mass, relative to the total amount (100 parts by mass) of the thermosetting resin (A) and the reactive liquid compound (B).
When the content of the radical polymerization initiator is equal to or more than the lower limit value, sufficient curing acceleration effect tends to be easily achieved and generation of a volatile component tends to be easily suppressed. When the content of the radical polymerization initiator is equal to or less than the upper limit value, storage stability tends to be improved.
The resin composition of the embodiment may further contain one or more optional components selected from the group consisting of a resin material other than the aforementioned components, a flame retarder, an antioxidant, a thermal stabilizer, an antistat, an ultraviolet absorber, a pigment, a colorant, a lubricant, an organic solvent, and the other additives as necessary.
Each of the optional components may be used alone, or may be used in combination of two or more types.
In the resin composition of the embodiment, the content of the optional component is not particularly limited, and may be used as necessary within a range not impairing the effects of the embodiment.
The resin composition of the embodiment may not contain the optional component depending on desired performance.
Since the resin composition of the embodiment has excellent flexibility, it is suitable as a resin composition constituting a resin film.
From the viewpoint of more effectively exhibiting features of the resin composition of the embodiment having excellent flexibility, the resin composition of the embodiment is preferably used for forming a resin film having a thickness of 10 μm or more, more preferably used for forming a resin film having a thickness of 50 μm or more, further preferably used for forming a resin film having a thickness of 80 μm or more, still more preferably used for forming a resin film having a thickness of 100 μm or more, still more preferably used for forming a resin film having a thickness of 130 μm or more, and particularly preferably used for forming a resin film having a thickness of 150 μm or more.
From the viewpoint of ease of handling, the resin composition of the embodiment is preferably used for forming a resin film having a thickness of 1,000 μm or less, more preferably used for forming a resin film having a thickness of 700 μm or less, and further preferably used for forming a resin film having a thickness of 500 μm or less.
A resin film of the embodiment is a resin film including the resin composition of the embodiment.
The resin film of the embodiment can be produced by, for example, applying the resin composition of the embodiment containing an organic solvent or, in other words, a resin varnish, to a support and then heating and drying it.
Examples of the support include a plastic film, a metal foil, and a release paper.
Examples of the plastic film include a film of polyolefin such as polyethylene, polypropylene, or polyvinyl chloride; a film of polyester such as polyethylene terephthalate [hereinafter sometimes referred to as “PET.”] or polyethylene naphthalate; a polycarbonate film; and a polyimide film. Among them, from the viewpoint of cost efficiency and ease of handling, a polyethylene terephthalate film is preferred.
Examples of the metal foil include a copper foil and an aluminum foil. When a copper foil is used as the support, the copper foil may be used as it is as a conductor layer for forming a circuit. In this case, as the copper foil, a rolled copper foil, an electrolytic copper foil, or the like may be used. When a thin copper foil is used, a copper foil with carrier may be used from the viewpoint of improving workability.
The support may have been subjected to surface treatment such as matte finishing or corona treatment. The support may have been subjected to release treatment with a silicone resin-based release agent, an alkyd resin-based release agent, a fluororesin-based release agent, or the like.
The thickness of the support is not particularly limited, but from the viewpoint of ease of handling and cost efficiency, it is preferably 10 to 150 μm, more preferably 20 to 100 μm, and further preferably 25 to 50 μm.
As a coater for applying the resin varnish, a coater known to those skilled in the art such as a comma coater, a bar coater, a kiss coater, a roll coater, a gravure coater, or a die coater may be used. Selection from these coaters may be made appropriately depending on the thickness of the film to be formed.
Conditions for drying the resin varnish after applying it are not particularly limited, and may be appropriately determined depending on the content, boiling point, and the like of the organic solvent.
For example, for a resin varnish containing 40 to 60 mass % of aromatic hydrocarbon-based solvent, the drying temperature is not particularly limited, but from the viewpoint of productivity and curing the resin composition of the embodiment to an appropriate extent into B-stage, it is preferably 50 to 200° C., more preferably 80 to 150° C., and further preferably 100 to 130° C.
For the aforementioned resin varnish, the drying time is not particularly limited, but from the viewpoint of productivity and curing the resin composition of the embodiment to an appropriate extent into B-stage, it is preferably 1 to 30 minutes, more preferably 2 to 15 minutes, and further preferably 3 to 10 minutes.
The content of the organic solvent in the resin film of the embodiment is preferably 2 mass % or less, more preferably 1 mass % or less, further preferably 0.5 mass % or less, or may be 0 mass %, relative to the total amount (100 mass %) of the resin film. When the content of the organic solvent in the resin film falls within the aforementioned range, the amount of the organic solvent that volatilizes during heating and curing tends to be easily suppressed sufficiently.
The mass reduction rate during heating and drying in an air atmosphere at 170° C. for 30 minutes [hereinafter sometimes referred to as “170° C. mass reduction rate.”] of the resin film of the embodiment is preferably 2.0 mass % or less, more preferably 1.5 mass % or less, further preferably 1.0 mass % or less, or may be 0 mass %.
When the 170° C. mass reduction rate falls within the aforementioned range, the amount of volatile component during heating and curing tends to be easily suppressed sufficiently.
The 170° C. mass reduction rate can be measured by the method described in Examples.
The thickness of the resin film of the embodiment may be appropriately determined depending on use application of the resin film, but from the viewpoint of achieving sufficient insulation reliability and enabling embedding of a semiconductor chip and the like, it is preferably 10 μm or more, more preferably 50 μm or more, further preferably 80 μm or more, still more preferably 100 μm or more, still more preferably 130 μm or more, and particularly preferably 150 μm or more.
From the viewpoint of ease of handling, the thickness of the resin film of the embodiment is preferably 1,000 μm or less, more preferably 700 μm or less, and further preferably 500 μm or less.
The resin film of the embodiment may have a protective film. The protective film may be disposed on the side opposite to the side where the support is disposed of the resin film of the embodiment, and is used to prevent adhesion of a foreign substance and the like to the resin film and scratching.
The relative dielectric constant (Dk) at 10 GHz of a cured product of the resin composition of the embodiment and that of the resin film may be less than 3.0, less than 2.9, or less than 2.8. The smaller the relative dielectric constant (Dk), the more preferred it is; the lower limit value thereof is not particularly limited, but it may be, for example, 2.4 or more or 2.5 or more with balance with other physical properties taken into account.
The dielectric loss tangent (Df) at 10 GHz of the cured product of the resin composition of the embodiment and that of the resin film may be less than 0.0030, less than 0.0025, or less than 0.0015. The smaller the dielectric loss tangent (Df), the more preferred it is; the lower limit value thereof is not particularly limited, and may be, for example, 0.0010 or more or 0.0015 or more with balance with other physical properties taken into account.
From the viewpoint of achieving sufficient insulation reliability and enabling embedding of a semiconductor chip and the like, it is preferable that the resin film of the embodiment be a resin film having a thickness of 150 μm or more, and a cured product of the resin film have a relative dielectric constant (Dk) at 10 GHz of less than 2.8 and a dielectric loss tangent (Df) of less than 0.0030.
The relative dielectric constant (Dk) and the dielectric loss tangent (Df) are values in conformity with a cavity resonator perturbation method and, more specifically, values measured by the method described in Examples.
The resin film of the embodiment is suitable as, for example, a resin film for forming an insulation layer of a printed wiring board such as a multilayer printed wiring board, a resin film for semiconductor encapsulation of a semiconductor package, or a backside protective film of a semiconductor chip. In particular, since the resin film of the embodiment is excellent in adhesion to a silicon wafer and flexibility, and is excellent in ease of handling when formed into a thick resin film, it is suitable as a resin film for semiconductor encapsulation.
A printed wiring board of the embodiment is a printed wiring board including a cured product of the resin composition of the embodiment.
The printed wiring board of the embodiment can be manufactured by, for example, forming a conductor circuit on one or more selected from the group consisting of a cured product of a prepreg of the embodiment, and a cured product and a laminate plate of the resin film of the embodiment by a known method. It is also possible to manufacture a multilayer printed wiring board by further applying multilayer-forming adhesion processing as necessary. A conductor circuit can be formed by, for example, appropriately performing perforating, metal plating, metal foil etching, and the like.
A semiconductor package of the present embodiment is a semiconductor package including a cured product of the resin film of the embodiment. That is, the semiconductor package of the embodiment can be said to be a semiconductor package including the resin film of the embodiment.
For example, the semiconductor package of the embodiment may be configured such that a semiconductor chip is mounted on the printed wiring board of the embodiment, or may include a semiconductor chip protected by a cured product of the resin film of the embodiment.
The semiconductor package configured such that a semiconductor chip is mounted on the printed wiring board of the embodiment can be manufactured by, for example, mounting a semiconductor chip, a memory, and the like on the printed wiring board of the embodiment by a known method. The printed wiring board of the embodiment for use in manufacturing of a semiconductor package is preferably a multilayer printed wiring board.
Examples of the semiconductor package including a semiconductor chip protected by a cured product of the resin film of the embodiment include a semiconductor package including a semiconductor chip encapsulated with a cured product of the resin film of the embodiment and a semiconductor package including a semiconductor chip of which the backside is protected by a cured product of the resin film of the embodiment.
The semiconductor package including a semiconductor chip encapsulated with a cured product of the resin film of the embodiment can be manufactured by, for example, the following method.
Firstly, the resin film of the embodiment is disposed on a semiconductor chip. Subsequently, the resin film is heated and melted to embed the semiconductor chip in the resin composition constituting the resin film. Thereafter, the resin composition in which the semiconductor chip is embedded is cured under heating to form a semiconductor chip encapsulated with the cured product of the resin film; the post-encapsulation semiconductor chip is mounted on a substrate; thus, the semiconductor package can be manufactured.
Regarding the semiconductor package including a semiconductor chip of which backside is protected by a cured product of the resin film of the embodiment, for example, by applying the resin film of the embodiment to backside of a semiconductor wafer and curing the resin composition by heating it, a protective film is formed on the backside of the semiconductor wafer. By grinding and dicing the semiconductor wafer with protective film, a semiconductor chip with protective film is obtained; by mounting the semiconductor chip on a substrate, the semiconductor package can be manufactured.
Hereinafter, the embodiment is described specifically by way of Examples. It should be noted that the embodiment is not limited to the following Examples.
The number average molecular weights were measured by the following procedure.
The number average molecular weights were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) (manufactured by TOSOH CORPORATION, trade names). GPC measurement conditions are given below.
In a 2-L heatable and coolable glass flask equipped with a thermometer, a reflux condenser, and a stirrer, 33.8 parts by mass of 1,2-polybutadiene homopolymer (number average molecular weight=1,200, vinyl group content=85% or more), 1.43 parts by mass of aromatic bismaleimide resin containing an indane ring (the compound represented by the general formula (A1-4-1), number average molecular weight=1,300), 0.0035 parts by mass of t-butyl peroxy isopropyl carbonate, and toluene as an organic solvent were placed. Subsequently, they were stirred in a nitrogen atmosphere at 90 to 100° C. for five hours to allow them to react; thus, a solution of modified conjugated diene polymer (solid content concentration: 35 mass %) was obtained. The number average molecular weight of the obtained modified conjugated diene polymer was 1,700.
GPC of a solution containing 1,2-polybutadiene homopolymer and aromatic bismaleimide resin containing an indane ring before initiation of the reaction and that of the solution after the reaction were measured using the aforementioned method to determine peak areas derived from the aromatic bismaleimide resin containing an indane ring before and after the reaction. Subsequently, a vinyl group modification rate of the aromatic bismaleimide resin containing an indane ring was calculated using the following equation. The vinyl group modification rate corresponds to the reduction rate of the peak area derived from the aromatic bismaleimide resin containing an indane ring due to the reaction.
The vinyl group modification rate determined using the equation was 40%.
The components listed in Table 1 and toluene were blended in accordance with the blending amounts listed in Table 1, and then stirred and mixed under heating at 25° C. or to 50 to 80° C., thereby prepared resin compositions having a solid content concentration of approximately 50 mass %. In Table 1, the unit for blending amount of each component is parts by mass, and that for a solution means parts by mass on a solid content basis.
The resin composition obtained in each Example was applied to one side of a 50-μm-thick PET film (manufactured by TOYOBO CO., LTD, trade name “Purex A53”) such that a resin layer after drying achieved a thickness of 150 μm. Thereafter, the resin composition was cured to B-stage by heating and drying it at 105° C. for five minutes; thus, a resin film with PET film on one side (1) (the thickness of the resin film was 150 μm) was prepared.
Next, the obtained resin film with PET film on one side (1) was cut out into 200 mm×200 mm pieces, which were overlaid on one another with the resin films facing each other. Subsequently, the pieces were bonded to each other using a vacuum laminator at a temperature of 100° C. for a pressing time of five seconds; thus, a resin film with PET film on both sides (2) (the thickness of the resin film was 300 μm) was obtained.
[Production of Resin Plate with Copper Foil on Both Sides]
The obtained resin film with PET film on both sides (2) was cut out into a piece of 90 mm in length and 50 mm in width, and the PET film was peeled and removed from each side. A 0.3-mm-thick Teflon (registered trademark) sheet die-cut into a size of 90 mm in length and 50 mm in width was placed on a copper foil, the resin film from which the PET films were peeled off was put on the die-cut portion and, furthermore, a copper foil was placed thereon to obtain a laminate. As the copper foil, a low-profile copper foil having a thickness of 18 μm (manufactured by MITSUI MINING & SMELTING CO., LTD, trade name “3EC-VLP-18”) was used, and it was placed such that its matte side faces the resin film. Subsequently, the laminate was formed by heating and pressing it under temperature, pressure, and time conditions of 180° C., 2.0 MPa, and 60 minutes to cure the resin film while forming it into a resin plate; thus, a resin plate with copper foil on both sides was prepared. The thickness of the resin plate portion of the obtained resin plate with copper foil on both sides was 0.3 mm.
Measurement and evaluation were performed using the resin films and the resin plates with copper foil on both sides obtained in Examples and Comparative Examples in accordance with the following methods. The results are shown in Table 1.
The resin film with PET film on one side (1) obtained in each Example was wound around a resin cylinder having a diameter of 85 mm with the resin film surface facing outward at 25° C. The appearance of the wound resin film was visually observed and evaluated against the following criteria. In the following criteria, “A” means most excellent.
The resin plate with copper foil on both sides obtained in each Example was immersed in a 10 mass % solution of ammonium persulfate (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.), which was a copper etchant, to remove the copper foil. A test piece was produced by cutting out a piece of 0.4 mm in width and 20 mm in length from the obtained resin plate and then drying it at 105° C. for one hour. Both longitudinal ends of the test piece were gripped with upper and lower jaws with a clearance of 10 mm between the jaws. Subsequently, a dimensional change was determined using a thermo-mechanical analyzer (TMA) (manufactured by Seiko Instruments Inc., trade name “SS6100”) in a tensile mode at a temperature range of 30 to 300° C., with a temperature increasing rate of 5° C./min, and a load of 4 g. A glass transition temperature and a linear expansion coefficient were evaluated against the following criteria, in which the glass transition temperature is the inflection point of the dimensional change with respect to the temperature, and the linear expansion coefficient is the mean value of dimensional changes per unit temperature at 30 to 150° C. In the following criteria, “A” means most excellent.
The resin plate with copper foil on both sides obtained in each Example was immersed in a 10 mass % solution of ammonium persulfate (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.), which was a copper etchant, to remove the copper foil. A test piece was produced by cutting out a piece of 10 mm in width and 40 mm in length from the obtained resin plate and then drying it at 105° C. for one hour. Both longitudinal ends of the test piece were gripped with upper and lower jaws with a clearance of 20 mm between the jaws. Subsequently, the tensile modulus of elasticity of the test piece was determined using a compact table-top universal tester (manufactured by Shimadzu Corporation, trade name “EZ-TEST”) in an environment of 25° C. under a condition of a tensile speed of 2 mm/min. Five identical samples were prepared, the tensile moduli of elasticity of them were determined under the same conditions as mentioned above, and their mean value was determined as a tensile modulus of elasticity at 25° C. Other detailed conditions and the method for calculating the tensile modulus of elasticity were in accordance with international organization for standardization ISO 5271 (1993). The obtained tensile modulus of elasticity at 25° C. was evaluated against the following criteria. In the following criteria, “A” means most excellent.
A test piece was produced by processing the copper foil of the resin plate with copper foil on both sides obtained in each Example into a 5-mm-wide straight ribbon by etching, and then drying it at 105° C. for one hour. The thus-formed straight-ribbon-like copper foil was attached to a compact table-top universal tester (manufactured by Shimadzu Corporation, trade name “EZ-TEST”) and peeled off in a direction of 90° to measure the peel strength of the copper foil. The tensile speed for peeling off the copper foil was 50 mm/min. The obtained peel strength was evaluated against the following criteria. In the following criteria, “A” means most excellent.
The resin film with PET film on one side (1) obtained in each Example was laminated to a silicon wafer (of 8-inch size) with the resin film adhered thereto. The lamination was performed by a method of, after reducing the pressure at 100° C. for 15 seconds to 0.5 MPa, applying the pressure for 45 seconds, and thereafter performing pressing at 130° C. for 60 seconds with a press-bonding pressure of 0.5 MPa.
Subsequently, the resin film, to which the PET film was still attached, was heated in an explosion-proof dryer at 180° C. for 60 minutes to form a cured resin layer by curing the resin film, and the PET film was peeled off from the cured resin layer.
Adhesion of the cured resin layer on the silicon wafer formed as described above to the silicon wafer was evaluated by a cross-cut test.
Specifically, a lattice pattern was cut into the cured resin layer prepared as described above by making six cuts with 2-mm spacing using an utility knife and then, at an angle of 90 degrees with respect to these cuts, making six cuts with 2-mm spacing. Subsequently, after firmly applying a cellulose tape (manufactured by NICHIBAN Co., Ltd., trade name “Cellotape (registered trademark)”) over the lattice-pattern cut, the cellulose tape was removed by pulling it off at an angle of 45 degrees. After peeling off the cellulose tape, observation for any detachment of the cured resin layer on the silicon wafer was made, and evaluation was conducted against the following criteria. In the following criteria, “A” means most excellent.
The resin plate with copper foil on both sides obtained in each Example was immersed in a 10 mass % solution of ammonium persulfate (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.), which was a copper etchant, to remove the copper foil. A test piece was produced by cutting out a piece of 2 mm×50 mm from the obtained resin plate and then drying it at 105° C. for one hour. Subsequently, the relative dielectric constant (Dk) and the dielectric loss tangent (Df) of the test piece were measured at an atmosphere temperature of 25° C. in 10 GHz band in accordance with a cavity resonator perturbation method, and evaluated against the following criteria. In the following criteria, “A” means most excellent.
A test piece was produced by cutting out a piece of 10 mm in length and 10 mm in width from the resin plate obtained by removing the copper foil from the resin plate with copper foil on both sides obtained in each Example by etching. The test piece was blackened using a graphite spray, and thereafter its thermal diffusivity was evaluated using a xenon flash analyzer (manufactured by NETZSCH, trade name “LFA447 nanoflash”). The thermal conductivity of the test piece was calculated from the product of this value, the density measured by an Archimedes method, and a specific heat measured using a differential scanning calorimeter (DSC) (manufactured by Perkin Elmer, trade name “DSC Pyris1”). The obtained thermal conductivity was evaluated against the following criteria. In the following criteria, “A” means most excellent.
An evaluation sample was prepared as B-stage powder by peeling and removing the PET film from the resin film with PET film on one side (1) obtained in each Example and then grinding the resin film. Using the evaluation sample, a mass reduction rate during heating and drying in an air atmosphere at 170° C. for 30 minutes [{(mass before heating-mass after heating at 170° C. for 30 minutes)/(mass before heating)}×100] was determined as 170° C. mass reduction rate. The results are shown in Table 1. In Table 1, “<1.0” indicates that the 170° C. mass reduction rate was 1.0 mass % or less.
Details of the components listed in Table 1 are as follows.
The above results show that the cured products of the resin compositions obtained in Examples 1 to 17 of the embodiment are each excellent in adhesion to a silicon wafer, and the resin films formed from the resin compositions are excellent in flexibility. Furthermore, the resin films of Examples 1 to 17 have the 170° C. mass reduction rate of 1.0 mass % or less, which indicates that generation of a volatile component during heating and curing is suppressed. On the other hand, the resin films of Comparative Examples 1 and 2 are inferior in flexibility, and the cured product of the resin composition of Comparative Example 3 is inferior in adhesion to a silicon wafer.
The resin composition of the embodiment is useful for printed wiring boards, semiconductor packages, and the like because, while being excellent in flexibility in a solid state, it can suppress generation of a volatile component during heating and curing and forms a cured product having excellent adhesion to a silicon wafer.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-212314 | Dec 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/046436 | 12/25/2023 | WO |
