Curable composition, cured product and electronic device

Abstract

To provide a curable composition comprising a polyimide and other components, with excellent compatibility between the polyimide and the other components, while enabling the formation of a cured film with a low dielectric loss tangent.SOLUTION: A curable composition comprises a polyimide or a precursor thereof (A) and a maleimide compound (B) with at least one aromatic ring structure and at least three maleimide groups.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a curable composition, a cured product, and an electronic device. [Background technology]

[0002] In the manufacture of electronic devices, a cured film may be formed using a curable composition containing a polyimide or a precursor thereof. As an example, Patent Document 1 describes the formation of an insulating film in an electronic component using a composition containing a polyimide resin having specific structural units. Patent Document 2 describes a polyimide resin containing a structure represented by a specific chemical formula, the use of the polyimide resin to prepare a negative-type photosensitive resin composition, and the use of the composition to form an organic insulating film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-172834 A [Patent Document 2] International Publication No. 2020 / 017920 Summary of the Invention [Problem to be solved by the invention]

[0004] It is considered that a cured film having various improved properties can be obtained by combining a polyimide with other components. For example, it is preferable to obtain a composition containing a polyimide or a precursor thereof that can form a cured film having a low dielectric loss tangent by combining a polyimide with other components. With the recent evolution of high frequency devices, there is an increasing demand for compositions capable of forming resin films with low dielectric tangents.

[0005] However, when polyimide is used in combination with other components, compatibility between the polyimide and the other components becomes an issue, and there is a concern that a homogeneous composition cannot be obtained. Furthermore, if an inappropriate compound is selected as the other component, there is a concern that a cured product having good properties such as a low dielectric tangent may not be obtained.

[0006] The present invention has been made in view of the above circumstances. An object of the present invention is to provide a curable composition containing a polyimide and other components, which has good compatibility with the polyimide and other components and is capable of forming a cured film with a low dielectric tangent. [Means for solving the problem]

[0007] The present inventors have completed the invention provided below and have solved the above problems.

[0008] 1. A polyimide or a precursor thereof (A); A maleimide compound (B) having at least one aromatic ring structure and three or more maleimide groups; 1. A curable composition comprising: 2. 1. The curable composition according to claim 1, The maleimide compound (B) is a polymer having a weight average molecular weight of 2,000 to 100,000. 3. 1. The curable composition according to 1. or 2., The maleimide compound (B) is a polymer having a weight average molecular weight of 2,000 to 50,000. 4. 1. The curable composition according to 1. or 2., A curable composition, wherein at least a part of the maleimide groups in the maleimide compound (B) is a group containing a maleimide skeleton represented by the following general formula (MI): [ka] In the general formula (MI), The Two R's 1 are each independently a hydrogen atom or a monovalent organic group, and two R 1 At least one of the groups is a monovalent organic group, * indicates a bond to another chemical structure. 5. 4. The curable composition according to claim 1, R 1 wherein the monovalent organic group is a methyl group. 6. 1. The curable composition according to 1. or 2., The maleimide compound (B) has a partial structure represented by the following general formula (I): [ka] In general formula (I), R MI represents a maleimide skeleton-containing group, L represents a single bond or a divalent linking group. R represents a monovalent substituent; m is an integer of 1 or more, n is an integer of 0 or more, and m+n≦4. 7. 1. The curable composition according to 1. or 2., A curable composition, wherein the polyimide or its precursor (A) has a maleimide group at one or both ends. 8. 7. The curable composition according to claim 7, A curable composition, wherein at least a part of the maleimide groups present at one or both ends of the polyimide or its precursor (A) is a group containing a maleimide skeleton represented by the following general formula (MI): [ka] In the general formula (MI), The Two R's 1 are each independently a hydrogen atom or a monovalent organic group, and two R 1 At least one of the groups is a monovalent organic group, * indicates a bond to another chemical structure. 9. 1. The curable composition according to 1. or 2., A curable composition, wherein the amount of the polyimide or its precursor (A) in the composition is 10 to 150 parts by mass per 100 parts by mass of the maleimide compound (B). 10. 1. The curable composition according to 1. or 2., The curable composition further comprising one or both of a photosensitizer and a photoinitiator. 11. 1. The curable composition according to 1. or 2., The curable composition further comprises an adhesion aid. 12. 1. The curable composition according to 1. or 2., The curable composition is a varnish in which the polyimide or its precursor (A) and the maleimide compound (B) are dissolved in an organic solvent. 13. A cured product of the curable composition according to 1. or 2. 14. 13. A cured product of the curable composition according to claim 12, A hardened product having a dielectric tangent of 0.006 or less at a frequency of 10 GHz. 15. 13. An electronic device comprising the cured product according to claim 13. Effect of the Invention

[0009] In the curable composition of the present invention, the polyimide has good compatibility with other components. Furthermore, by using the curable composition of the present invention, a cured film having a low dielectric loss tangent can be formed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, similar components are given similar symbols and descriptions thereof will be omitted as appropriate. In order to avoid complexity, when there are multiple identical components in the same drawing, only one of them may be labeled with a reference symbol, and not all of them. The drawings are for illustrative purposes only. The shapes and dimensional ratios of the components in the drawings do not necessarily correspond to the actual products.

[0012] In this specification, unless otherwise specified, the expression "X to Y" in the explanation of a numerical range means from X to Y. For example, "1 to 5% by mass" means "from 1% by mass to 5% by mass".

[0013] In the general formula representation of chemical structures in this specification, when a general formula 1 contains a plurality of identical symbols, each symbol may have the same chemical structure or different chemical structures within the scope of the definition of each symbol. For example, in the general formula (I) shown below, when n is 2, there are two Rs, and the two Rs may have the same chemical structure or different chemical structures.

[0014] In the description of groups (atomic groups) in this specification, when a description is made without specifying whether the group is substituted or unsubstituted, the description includes both groups having no substituents and groups having a substituent. For example, an "alkyl group" includes not only an alkyl group having no substituents (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). In this specification, the term "(meth)acrylic" refers to a concept that includes both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate." In this specification, the term "organic group" means an atomic group obtained by removing one or more hydrogen atoms from an organic compound, unless otherwise specified. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound. In this specification, the term "electronic device" is used to encompass elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

[0015] <Curable composition> The curable composition of the present embodiment contains (A) a polyimide or a precursor thereof, and (B) a maleimide compound having at least one aromatic ring structure and three or more maleimide groups.

[0016] Although it is speculation, it is believed that the compatibility of these two components is good because the imide ring structure of the polyimide (or the amic acid structure of the polyimide precursor) and the maleimide structure of the maleimide compound are structurally similar. In particular, the compatibility may be improved by the maleimide compound (B) having three or more maleimide groups. It is believed that the good compatibility of these two components makes it easier to prepare a uniform composition. In addition, it is presumed that the maleimide compound (B) contains an aromatic ring structure, and thus the cured product has a low dielectric tangent.

[0017] Hereinafter, the components that can be contained in the curable composition of the present embodiment and specific embodiments of the curable composition of the present embodiment will be further described.

[0018] (Polyimide or its precursor (A))

[0019] Polyimide or its precursor (A) is not particularly limited. Polyimide is a general term for polymers containing imide bonds, and is usually an aromatic polyimide in which aromatic compounds are directly linked by imide bonds. Also, polyamic acid can usually be used as a precursor of polyimide.

[0020] The polyimide or its precursor (A) preferably contains a polyimide (or its precursor) having a maleimide skeleton, that is, the polyimide or its precursor (A) preferably has a maleimide group at one or both ends. By using such a polyimide or its precursor (A), it is possible for the polyimide or its precursor (A) to react with the maleimide compound (B) to increase its molecular weight, or for the polyimide or its precursor (A) to react with itself to increase its molecular weight, which is expected to result in a stronger crosslinked structure in the cured product, leading to further improvement in heat resistance. Furthermore, an increase in the amount of maleimide groups in the composition (increased concentration) can be expected to result in an improvement in the curing speed.

[0021] Specifically, at least a part of the maleimide groups present at one or both ends of the polyimide or its precursor (A) is preferably a group containing a maleimide skeleton represented by the following general formula (MI): Also, a specific example of the maleimide group present at one or both ends of the polyimide or its precursor (A) is the maleimide group in the terminal structure represented by the below-mentioned general formula (t-1).

[0022] [ka]

[0023] In the general formula (MI), The Two R's 1 each independently represents a hydrogen atom or a monovalent organic group, * indicates a bond to another chemical structure.

[0024] R 1 The monovalent organic group is preferably a linear or branched alkyl group, more preferably a methyl group.

[0025] As an example of the group represented by the general formula (MI), 1 Preferably, one of the R1 It is more preferable that one of the R 1 The other of these is preferably a hydrogen atom. As another example, in the group represented by the general formula (MI), 1 It is preferable that both of R are monovalent organic groups, and 1 It is more preferable that both of these are methyl groups. According to the findings of the present inventors, two R 1 When one of the groups is a monovalent organic group, the curability (curing speed) tends to be the best.

[0026] Specifically, the polyimide or its precursor (A) can have a structural unit represented by the following general formula (1) (when (A) is a polyimide precursor, it can have a corresponding amic acid structural unit).

[0027] [ka]

[0028] A in the general formula (1) represents a ring structure containing two carbon atoms of the imide ring in the formula, and is preferably an aromatic ring such as a benzene ring or a naphthalene ring.

[0029] In general formula (1), Q represents a divalent organic group, and is preferably a divalent group containing an imide ring. In the general formula (1), X represents a divalent organic group containing an aromatic group. In X of the general formula (1), the aromatic group contained in the divalent organic group is preferably bonded to the nitrogen atom in the general formula (1). The two ortho positions to the carbon atom of the aromatic group bonded to the nitrogen atom are more preferably provided with electron donating groups, and even more preferably with asymmetric electron donating groups. Examples of the electron donating groups include a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, and an alkoxy group having 1 to 3 carbon atoms. The divalent organic group of X may be a divalent group represented by the following general formula (1a) or (1b): When X contains a structural unit that is one of these groups, the glass transition temperature of the cured product may be increased. X can contain at least one divalent group represented by general formula (1a) or at least one divalent group represented by general formula (1b), and can also contain a combination of these groups.

[0030] [ka]

[0031] In general formula (1a), R 1 ~R 4 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms; R 1 and R 2 are different groups, and R 3 and R 4 are different groups.

[0032] X 1 represents a single bond, -SO2-, -C(=O)-, a linear or branched alkylene group having 1 to 5 carbon atoms, or a fluorenylene group. * represents a bond.

[0033] In general formula (1b), R a , R b each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms. a R b may be the same or different. * indicates a bond. The two ortho positions (R 1 and R 2 (or R 3 and R 4 )) preferably has a specific electron-donating group in terms of further improving the effect, and X in general formula (1) is more preferably a divalent group represented by general formula (1a).

[0034] Specifically, the structural unit represented by the general formula (1) preferably contains a structural unit represented by the following general formula (1-1).

[0035] [ka]

[0036] In the general formula (1-1), X can be a divalent group represented by the general formula (1a) or (1b).

[0037] In the general formula (1-1), Y is a divalent organic group. Specifically, the divalent organic group can be selected from the following general formula (a1-1), the following general formula (a1-2), the following general formula (a1-3), and the following general formula (a1-4).

[0038] [ka]

[0039] In general formula (a1-1), R 7 and R 8 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, 7 R 8 They may be the same or different. R 7 and R 8 From the viewpoint of effectiveness, is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.

[0040] R 9 represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and 9 They may be the same or different. R 9 From the viewpoint of effectiveness, is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom. * indicates a bond.

[0041] In general formula (a1-2), R 10 and R 11 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, 10 R 11 They may be the same or different.

[0042] R 10 and R 11 From the viewpoint of effectiveness, R is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably R 10 At least one of and R 11 At least one of R is an alkyl group having 1 to 3 carbon atoms, and more preferably, three R 10 is an alkyl group having 1 to 3 carbon atoms, and one R 10 is a hydrogen atom and three R 11 is an alkyl group having 1 to 3 carbon atoms, and one R 11 is a hydrogen atom, and particularly preferably, three R 10 is a methyl group and one R 10 is a hydrogen atom and three R 11 is a methyl group and one R 11 is a hydrogen atom. * indicates a bond.

[0043] In general formula (a1-3), Z 1 represents an alkylene group having 1 to 5 carbon atoms or a divalent aromatic group. * represents a bond.

[0044] In general formula (a1-4), Z 2 represents a divalent aromatic group, preferably a divalent benzene ring. * represents a bond.

[0045] The polyimide or its precursor (A) can contain at least one structural unit selected from the structural unit (1-1a) represented by the following general formula (1-1a) and the structural unit (1-1b) represented by the following general formula (1-1b).

[0046] [ka]

[0047] In general formula (1-1a), R 1 ~R 4 , X 1 is X in general formula (1a) 1 and Y has the same meaning as Y in general formula (1-1).

[0048] [ka]

[0049] In general formula (1-1b), R a and R b has the same meaning as in formula (1b), and Y has the same meaning as in formula (1-1).

[0050] From the viewpoint of effectiveness, the polyimide or its precursor (A) preferably has a group t-1 represented by the following general formula (t-1) at at least one of both ends, preferably at both ends. By providing the maleimide compound (B) with such a terminal structure, a cured product having excellent mechanical strength can be obtained.

[0051] [ka]

[0052] In general formula (t-1), R 5 and R 6 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R 5 and R 6 At least one of the groups is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably both are alkyl groups having 1 to 3 carbon atoms. From the viewpoint of effectiveness, the alkyl group having 1 to 3 carbon atoms is preferably an alkyl group having 1 or 2 carbon atoms, and more preferably an alkyl group having 1 carbon atom. * indicates a bond.

[0053] Q 2 represents a divalent organic group. The divalent organic group may be a known organic group, and examples thereof include divalent organic groups represented by general formula (1a) or general formula (1b).

[0054] In addition, the polyimide or its precursor (A) may have at its terminal at least one type of group selected from a group u-1 represented by the following general formula (u-1) and a group u-2 represented by the following general formula (u-2).

[0055] [ka]

[0056] In general formula (u-1), X 1 , R 1 ~R 4 represents X in general formula (1a). 1 , R 1 ~R 4 is synonymous with. In general formula (u-2), R a , R b R in general formula (1b) a , R b is synonymous with.

[0057] When the polyimide or its precursor (A) has a group u-1 and / or a group u-2, the ratio of the number of moles of the group t-1 to the total number of moles of the group t-1 and the group u-1 and / or the group u-2 (t-1) / [(t-1)+(u-1)+(u-2)] can be, for example, 0.5 or more, preferably 0.55 or more, more preferably 0.6 or more. By appropriately adjusting this ratio, unintended elution during development can be reduced.

[0058] The weight average molecular weight of the polyimide or its precursor (A) is usually 25,000 to 200,000, preferably 30,000 to 150,000, and more preferably 40,000 to 100,000.

[0059] The curable composition of the present embodiment may contain only one polyimide or its precursor (A), or may contain two or more polyimides or its precursors (A). The amount of the polyimide or its precursor (A) in the non-volatile components of the curable composition of the present embodiment is, for example, 10 to 85 mass %, preferably 20 to 80 mass %, and more preferably 30 to 70 mass %. From another viewpoint different from the above, the amount of the polyimide or its precursor (A) in the curable composition is, for example, 10 to 150 parts by mass, preferably 20 to 140 parts by mass, and more preferably 30 to 130 parts by mass, relative to 100 parts by mass of the maleimide compound (B) described below. By appropriately adjusting the quantitative ratio of the polyimide or its precursor (A) to the maleimide compound (B), the balance of various performances can be optimized.

[0060] (Maleimide Compound (B)) The maleimide compound (B) is not particularly limited as long as it is a compound having at least one aromatic ring structure and three or more maleimide groups in one molecule. The maleimide compound (B) may be a low molecular weight compound, an oligomer, or a polymer. The maleimide compound (B) may or may not have a plurality of unit structures (typically repeating structures) derived from the raw material monomer.

[0061] At least a part of the maleimide groups in the maleimide compound (B) is preferably a group containing a maleimide skeleton represented by general formula (MI) described above in the section on polyimide or its precursor (A). 1 The preferred embodiments of the polyimide or its precursor (A) are as explained in the section on polyimide or its precursor (A). In other words, from the viewpoint of curability (curing speed), 1 At least one of the groups is preferably a monovalent organic group such as a methyl group.

[0062] The maleimide compound (B) preferably has a partial structure represented by the following general formula (I). When the maleimide compound (B) is a polymer or oligomer, the partial structure represented by general formula (I) may be a unit structure or a partial structure that is not a unit structure. In other words, when the maleimide compound (B) contains a partial structure represented by general formula (I), the maleimide compound (B) may contain the partial structure represented by general formula (I) in any form. Alternatively, when the maleimide compound (B) contains a partial structure represented by general formula (I), the partial structure represented by general formula (I) may be a part of a unit structure, i.e., the maleimide compound (B) may be a polymer or oligomer having a plurality of unit structures each including the partial structure represented by general formula (I). Any number of partial structures represented by general formula (I) may be present in maleimide compound (B). Maleimide compound (B) contains, for example, 6 or more, specifically 8 or more, and more specifically 10 or more partial structures represented by general formula (I). Maleimide compound (B) contains, for example, 100 or less, specifically 75 or less, and more specifically 50 or less partial structures represented by general formula (I). In addition, when maleimide compound (B) has a molecular weight distribution, the number shown here means the number of partial structures that one molecule of maleimide compound (B) has on average.

[0063] [ka]

[0064] In general formula (I), R MI represents a maleimide skeleton-containing group, L represents a single bond or a divalent linking group. X represents a single bond or a divalent linking group; R represents a monovalent substituent; m is an integer of 1 or more, n is an integer of 0 or more, and m+n≦4; * indicates a bond to another chemical structure.

[0065] RMI The maleimide skeleton-containing group is preferably a group containing a maleimide skeleton represented by the above-mentioned general formula (MI).

[0066] In the maleimide compound (B) represented by general formula (I), at least a part of X preferably contains a group represented by the following general formula (X1).

[0067] [ka]

[0068] In general formula (X1), Y represents an aromatic ring-containing group; The Four R's 2 each independently represents a hydrogen atom or a monovalent organic group.

[0069] Examples of the aromatic ring-containing group for Y include groups containing a benzene ring, a naphthalene ring, etc. Y is preferably a phenylene group or a naphthylene group, and more preferably a phenylene group.

[0070] R 2 Examples of the monovalent organic group include an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, and a cycloalkyl group. R 2 is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and further preferably a hydrogen atom. From the viewpoint of ease of synthesis, i.e., the yield during synthesis and the molecular weight of the product, four R 2 are preferably all hydrogen atoms.

[0071] X may be a single bond or a divalent linking group, but from the viewpoint of appropriate flexibility of the chemical structure and improved compatibility with other components in the composition, at least a part of X is preferably a heteroatom-containing group, more preferably an oxygen atom-containing group, and further preferably an ether bond-containing group. In addition, X is a benzene ring -LR MI (L and R MI is defined as in general formula (I).

[0072] Specific examples of the structure of X include structures including those derived from dialkenes represented by general formula (DA-1) and diols represented by general formula (DA-2) shown below.

[0073] As an example of the maleimide skeleton-containing group represented by general formula (MI), 1 Preferably, one of the R 1 It is more preferable that one of the R 1 The other of these is preferably a hydrogen atom. As another example, in the maleimide skeleton-containing group represented by general formula (MI), 1 It is preferable that both of R are monovalent organic groups, and 1 It is more preferable that both of these are methyl groups.

[0074] Based on the findings of the present inventors, in the maleimide skeleton-containing group represented by general formula (MI), 1 When both are hydrogen atoms, it is believed that two or more maleimide skeleton-containing groups are bonded through a radical polymerization reaction, thereby curing the composition. In contrast, two R 1 When both R are monovalent organic groups, the radical polymerization reaction hardly proceeds due to steric hindrance, and instead, a [2+2] photocyclization reaction proceeds. 1 When both are monovalent organic groups, it is believed that two or more maleimide skeleton-containing groups are bonded together through a [2+2] photocyclization reaction, thereby curing the composition. The Two R's 1 When one of the radicals is a monovalent organic group and the other is a hydrogen atom, the [2+2] photocyclization reaction dominates, although some radical polymerization reaction may also occur.

[0075] In this embodiment, the curing reaction may be a radical polymerization reaction or a [2+2] photocyclization reaction, or these may proceed simultaneously. However, from the viewpoint of ease of control of the reaction by heat or light, it is preferable that the [2+2] photocyclization reaction is dominant in the curing reaction. In this respect, 1 It is preferable that one or both of R are monovalent organic groups, and two R 1 It is more preferable that both of the above are monovalent organic groups. However, radical polymerization is a chain reaction, and it can be said that radical polymerization is advantageous, especially in terms of curing (curing speed). 1 When one of the R groups is a monovalent organic group and the other is a hydrogen atom, the [2+2] photocyclization reaction is dominant, but the radical polymerization reaction is also thought to proceed to a small extent. Therefore, from the viewpoint of overall performance, 1 It is considered preferable that one of the groups is a monovalent organic group (such as a methyl group) and the other is a hydrogen atom.

[0076] The maleimide compound (B) preferably contains a benzene ring, the skeleton of which is composed only of carbon and hydrogen, as an aromatic ring structure. In addition, it is preferable that the aromatic ring structure is not substituted with unnecessary substituents (particularly heteroatom-containing groups). A cured product formed using a curable composition containing such a maleimide compound (B) is expected to have particularly good dielectric properties.

[0077] In addition, since the maleimide compound (B) contains a benzene ring in the skeleton, it is considered that the cured product formed using the curable composition containing the polyimide or its precursor (A) is prevented from deteriorating due to oxidation. Since the cured product is less susceptible to oxidation, it is expected that the electronic device will have a longer life and higher reliability.

[0078] The maleimide compound (B) is preferably a polymer having a weight average molecular weight of 2000 to 100000, and more preferably a polymer having a weight average molecular weight of 2000 to 50000. The weight average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance. Incidentally, the maleimide compound (B) is usually a compound (polymer, oligomer) having a molecular weight distribution, but may be a compound having a single molecular weight. When the maleimide compound (B) is a compound having a single molecular weight, the molecular weight of the maleimide compound (B) is preferably about the above-mentioned numerical range.

[0079] The curable composition of the present embodiment may contain only one maleimide compound (B), or may contain two or more maleimide compounds (B). The amount of the maleimide compound (B) in the non-volatile components of the curable composition is, for example, 10 to 85 mass %, preferably 20 to 80 mass %, and more preferably 30 to 70 mass %.

[0080] Incidentally, it is preferable that the maleimide compound (B) does not include the following [Excluded Forms] (i) and (ii).

[0081] [Excluded forms] (i) In substantially all of the partial structures represented by general formula (I), X is -CH2-. (ii) In substantially all of the partial structures represented by general formula (I), X is a divalent group represented by general formula (X') below.

[0082] [ka]

[0083] In general formula (X'), The Two R's 3 each independently represents a group having 0 to 10 carbon atoms which may contain a heteroatom, Two m3's each independently represent an integer of 0 to 4.

[0084] (Photosensitizers and / or photoinitiators) The curable composition of the present embodiment preferably contains a photosensitizer and / or a photopolymerization initiator. This allows the curable composition of the present embodiment to have a sufficiently high sensitivity to light. In addition, the use of the photosensitizer and / or the photopolymerization initiator can improve the patterning property by light. In consideration of the mechanism of the curing reaction, some or all of the maleimide groups in the maleimide compound (B) are maleimide skeleton-containing groups represented by general formula (MI), and two R 1 When at least one of is a monovalent organic group, it is preferable to use a photosensitizer, which is believed to facilitate the [2+2] photocyclization reaction. In contrast, a part or all of the maleimide groups in the maleimide compound (B) are maleimide skeleton-containing groups represented by general formula (MI), and two R 1 When both are hydrogen atoms, it is preferable to use a photopolymerization initiator.

[0085] Preferred photosensitizers include the following compounds: Polynuclear aromatics (e.g., phenanthrene, anthracene, pyrene, perylene, triphenylene, 9,10-dialkoxyanthracene), xanthenes (e.g., fluorescein, eosin, erythrosine, rhodamine B, rose bengal), thioxanthones (isopropylthioxanthone, diethylthioxanthone, chlorothioxanthone), cyanines (e.g., thiacarbocyanine, oxacarbocyanine), merocyanines (e.g., merocyanine, carbomerocyanine), phthalocyanines, thiazines (e.g., thionine, methylene blue, toluidine blue), acridines (e.g., acridine orange, chloroflavine, acriflavine), anthraquinones (e.g., anthraquinone, laquinone), squaryliums (e.g., squarylium), acridine orange, coumarins (e.g., 7-diethylamino-4-methylcoumarin), ketocoumarin, phenothiazines, phenazines, styrylbenzenes, azo compounds, diphenylmethane, triphenylmethane, distyrylbenzenes, carbazoles, porphyrin, spiro compounds, quinacridone, indigo, styryl, pyrylium compounds, pyrromethene compounds, pyrazolotriazole compounds, benzothiazole compounds, barbituric acid derivatives, thiobarbituric acid derivatives, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone, and Michler's ketone, and heterocyclic compounds such as N-aryloxazolidinone.

[0086] In terms of the progress of the [2+2] photocyclization reaction, the sensitizer is preferably one having a maximum light absorption in the wavelength region of 300 to 450 nm.

[0087] When a photosensitizer is used, only one photosensitizer may be used, or two or more photosensitizers may be used. When a photosensitizer is used, the amount thereof is preferably from 1 to 50% by mass, and more preferably from 3 to 30% by mass, based on the non-volatile components of the curable composition.

[0088] Examples of the photopolymerization initiator include known photoradical generators. Specifically, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropane -1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone and other alkylphenone compounds; benzophenone, 4,4'-bis(dimethylamino)benzophenone, 2-carboxybenzophenone, etc. benzophenone compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzoin compounds such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-ethoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(4-ethoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine. halomethylated triazine compounds such as 2-trichloromethyl-5-(2'-benzofuryl)-1,3,4-oxadiazole, 2-trichloromethyl-5-[β-(2'-benzofuryl)vinyl]-1,3,4-oxadiazole, 4-oxadiazole, and 2-trichloromethyl-5-furyl-1,3,4-oxadiazole;Biimidazole compounds such as 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole; oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime); Bis(η; 5 Examples of the compound include titanocene-based compounds such as (2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium; benzoate-based compounds such as p-dimethylaminobenzoic acid and p-diethylaminobenzoic acid; and acridine-based compounds such as 9-phenylacridine.

[0089] When a photopolymerization initiator is used, only one photopolymerization initiator may be used, or two or more photopolymerization initiators may be used. When a photopolymerization initiator is used, the amount thereof is preferably from 1 to 50% by mass, more preferably from 3 to 30% by mass, based on the non-volatile components of the curable composition.

[0090] (Adhesion aid) The curable composition of the present embodiment may contain an adhesion aid, which can enhance the adhesion of the cured film to a substrate.

[0091] The adhesion aid that can be used is not particularly limited. For example, a silane coupling agent such as an aminosilane, an epoxysilane, a (meth)acrylic silane, a mercaptosilane, a vinylsilane, a ureidosilane, an acid anhydride functional silane, or a sulfide silane can be used.

[0092] Examples of aminosilanes include bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane.

[0093] Examples of epoxy silanes include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidylpropyltrimethoxysilane.

[0094] Examples of the (meth)acrylsilane include γ-(methacryloxypropyl)trimethoxysilane, γ-(methacryloxypropyl)methyldimethoxysilane, and γ-(methacryloxypropyl)methyldiethoxysilane.

[0095] An example of the mercaptosilane is 3-mercaptopropyltrimethoxysilane.

[0096] Examples of vinyl silanes include vinyl tris(β-methoxyethoxy) silane, vinyl triethoxy silane, and vinyl trimethoxy silane.

[0097] An example of the ureidosilane is 3-ureidopropyltriethoxysilane.

[0098] An example of an anhydride functional silane is 3-trimethoxysilylpropylsuccinic anhydride.

[0099] Examples of sulfide silanes include bis(3-(triethoxysilyl)propyl) disulfide and bis(3-(triethoxysilyl)propyl) tetrasulfide.

[0100] When an adhesion aid is used, only one adhesion aid may be used, or two or more adhesion aids may be used. When an adhesion aid is used, the amount thereof is preferably 1 to 50 mass %, more preferably 3 to 30 mass %, based on the non-volatile components of the curable composition. By setting the amount within this range, it is easy to sufficiently increase adhesion while maintaining a balance with other properties.

[0101] (Other optional ingredients) The curable composition of the present embodiment may contain optional components such as a curing reaction accelerator, an antioxidant, a filler, and a surfactant, as necessary.

[0102] (solvent) The curable composition of the present embodiment preferably contains a solvent. Specifically, the curable composition of the present embodiment is preferably a composition in which the above-mentioned components are dissolved or dispersed in a solvent. More specifically, the curable composition of the present embodiment is a varnish-like composition in which the polyimide or its precursor (A) and the maleimide compound (B) are dissolved in an organic solvent. The solvent is typically an organic solvent, and preferably consists essentially of an organic solvent and is substantially free of water.

[0103] Examples of the solvent include N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, cyclopentanone, cyclohexanone, methyl-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, methyl pyruvate, ethyl pyruvate, and methyl-3-methoxypropionate.

[0104] From the viewpoint of the solubility of the polyimide or its precursor (A) and the maleimide compound (B), the solvent preferably contains an amide solvent such as N-methylpyrrolidone and / or a lactone solvent such as γ-butyrolactone.

[0105] The solvent may be a single solvent or a mixed solvent. When a solvent is used, the amount used may be such that the concentration of non-volatile components in the curable composition becomes, for example, 5 to 40% by mass, and preferably 10 to 30% by mass.

[0106] <Cured product and electronic device> A cured product can be obtained by heating the curable composition of the present embodiment. This cured product is preferably incorporated into an electronic device. In other words, the curable composition of the present embodiment is preferably used to form a permanent film in an electronic device. A permanent film is a cured film that remains in an electronic device as a final product, such as an insulating film, unlike a sacrificial film such as a resist film. The permanent film can be a protective film, an interlayer film, a dam material, etc. of a semiconductor device. The cured product of the curable composition of this embodiment tends to have a relatively small dielectric loss tangent. Specifically, the cured product of the curable composition of this embodiment can have a dielectric loss tangent of 0.006 or less at a frequency of 10 GHz. The curable composition of this embodiment can be preferably applied to the manufacture of electronic devices such as high-frequency devices.

[0107] When the curable composition is photosensitive, a cured product (permanent film) can be formed by the following procedure: (1) The curable composition is applied onto a substrate to obtain an unexposed film. (2) The unexposed film is prebaked, exposed, and developed to obtain a pattern of the desired shape. The developer used for development may be an alkaline developer or an organic solvent-based developer, but is preferably an organic solvent-based developer. (3) The pattern thus obtained is post-baked to harden it. The permanent film can be used as a protective film, an interlayer film, a dam material, etc. in semiconductor devices.

[0108] In the above (2), examples of the alkaline developer include (i) aqueous solutions of inorganic alkali such as sodium hydroxide, sodium carbonate, sodium silicate, and ammonia; (ii) aqueous solutions of organic amines such as ethylamine, diethylamine, triethylamine, and triethanolamine; and (iii) aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide.

[0109] In the above (2), examples of the organic solvent contained in the organic solvent-based developer include ketone-based solvents, ester-based solvents, ether-based solvents, and alcohol-based solvents. Specific examples include acetophenone, methylacetophenone, diisobutyl ketone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 2-nonanone, cyclohexanone, methylcyclohexanone, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate, butenyl acetate, methyl propionate, ethyl propionate, methyl lactate, ethyl lactate, propyl lactate, butyric acid, and the like. Examples of the developer include a developer mainly composed of ethyl 3-ethoxypropionate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl crotonate, ethyl crotonate, methyl valerate, methyl pentenoate, methyl benzoate, benzyl formate, phenyl acetate, ethyl benzoate, phenylethyl formate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, 2-phenylethyl acetate, methyl 3-phenylpropionate, benzyl propionate, ethanol, 1-propanol, 2-propanol, etc. The organic solvent-based developer may contain only one organic solvent, or may contain two or more organic solvents. The organic solvent-based developer is usually composed of 90% or more by mass of the organic solvent. The organic solvent-based developer may contain other components in addition to the organic solvent, as long as the performance as the developer is not impaired. Examples of the other components include surfactants, etc. Examples of the surfactant include fluorine-based surfactants and silicone-based surfactants.

[0110] An example of an electronic device having a cured product (permanent film) is shown in FIG. The electronic device 100 can be a device including a cured product (permanent film). Specifically, in the electronic device 100, one or more of the group consisting of the passivation film 32, the insulating layer 42, and the insulating layer 44 can be a resin film including the cured product of the present embodiment.

[0111] The electronic device 100 is, for example, a semiconductor chip. In this case, for example, the electronic device 100 is mounted on a wiring board via bumps 52 to obtain a semiconductor package.

[0112] The electronic device 100 includes a semiconductor substrate on which semiconductor elements such as transistors are provided, and a multi-layer wiring layer (not shown) provided on the semiconductor substrate. The uppermost layer of the multi-layer wiring layer includes an interlayer insulating film 30 and a top-layer wiring 34 provided on the interlayer insulating film 30. The top-layer wiring 34 is made of, for example, aluminum Al. A passivation film 32 is provided on the interlayer insulating film 30 and the top-layer wiring 34. An opening is provided in a part of the passivation film 32 to expose the top-layer wiring 34.

[0113] A rewiring layer 40 is provided on the passivation film 32. The rewiring layer 40 has an insulating layer 42 provided on the passivation film 32, a rewiring 46 provided on the insulating layer 42, and an insulating layer 44 provided on the insulating layer 42 and the rewiring 46. An opening connected to the top layer wiring 34 is formed in the insulating layer 42. The rewiring 46 is formed on the insulating layer 42 and in the opening provided in the insulating layer 42, and is connected to the top layer wiring 34. An opening connected to the rewiring 46 is provided in the insulating layer 44.

[0114] Bumps 52 are formed, for example, via a UBM (Under Bump Metallurgy) layer 50, in the openings provided in the insulating layer 44. The semiconductor device 100 is connected, for example, via the bumps 52 to a wiring board or the like.

[0115] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention.

[0116] <Production method of maleimide compound (B)> The production method of the maleimide compound (B) will now be explained. The maleimide compound (B) can be produced, for example, through the following polymerization process and maleimidization process. Incidentally, the polymerization process utilizes the Friedel-Crafts reaction (particularly the Friedel-Crafts alkylation reaction). In elementary organic chemistry, it is known that a monoalkene or monool is reacted with an aromatic ring to obtain a low molecular weight compound, but in this embodiment, a dialkene or diol is used to obtain a compound (polymer or oligomer) having a relatively large molecular weight in which a plurality of aromatic ring-containing structures are linked via a linking group. In addition, a compound having a relatively large molecular weight can also be obtained by using an appropriate compound such as a diamine as the benzene ring-containing amine compound shown below.

[0117] ·Polymerization process In the presence of an acid, a benzene ring-containing amine compound substituted with at least one group represented by -L-NH2 (L represents a single bond or a divalent linking group) is reacted with a dialkene represented by the following general formula (DA-1) or a diol represented by the following general formula (DA-2) to obtain a polyfunctional amine having a plurality of partial structures represented by the following general formula (AM-2).

[0118] [ka]

[0119] In general formulas (DA-1) and (DA-2), Y represents an aromatic ring-containing group; R 2 each independently represents a hydrogen atom or a monovalent organic group. Y and R 2 A specific embodiment of the formula (X1) is 2 From the viewpoint of yield and high molecular weight of the product, 2 are preferably all hydrogen atoms.

[0120] [ka]

[0121] In the general formula (AM-2), L represents a single bond or a divalent linking group. X represents a single bond or a divalent linking group; R represents a monovalent substituent; m is an integer of 1 or more, n is an integer of 0 or more, and m+n≦4; * indicates a bond to another chemical structure. Specific embodiments of L, X, R, m, and n in general formula (AM-2) are the same as L, X, R, m, and n in general formula (I).

[0122] Maleimidation process: The polyfunctional amine obtained in the polymerization step is reacted with an acid anhydride represented by the following general formula (AA) to convert the -NH2 group in the polyfunctional amine into a maleimid group.

[0123] [ka]

[0124] In the general formula (AA), The Two R's 1 are each independently a hydrogen atom or a monovalent organic group. The Two R's 1 Regarding a specific embodiment of the above, two R 1 is the same as:

[0125] Examples of compounds that can be preferably used as the starting material in the polymerization step, which is a benzene ring-containing amine compound substituted with at least one group represented by -L-NH2, are given below.

[0126] [ka]

[0127] Examples of dialkenes or diols that are preferably used in the polymerization step are given below.

[0128] [ka]

[0129] Incidentally, when a dialkeny represented by the general formula (DA-1) is used in the polymerization process, X is -C(CH3)R 2 -YC(CH3)R 2 In contrast, when a diol represented by the general formula (DA-2) is used in the polymerization step, X is -CR 2 R 2 -Y-CR 2 R 2 - This includes the structure represented by the formula:

[0130] The polymerization step is carried out in the presence of an acid, which is not particularly limited, but includes hydrochloric acid, sulfuric acid, phosphoric acid, aluminum chloride, methanesulfonic acid, p-toluenesulfonic acid and its hydrates, activated clay, and the like. The polymerization step may be carried out with or without a solvent, and in the latter case, if some of the raw materials are solid at room temperature, the raw materials may be heated to melt them and then stirred to allow the reaction to proceed. The reaction temperature in the polymerization step is preferably 100 to 250° C., and the reaction time is preferably 1 to 24 hours. Other reaction conditions can be determined by reference to past knowledge regarding the Friedel-Crafts alkylation reaction.

[0131] In the polymerization step, as a part of the raw material amine, a substituted aniline having an aniline skeleton and in which the hydrogen atom bonded to the carbon atom adjacent to the carbon atom bonded to the -NH2 group is replaced with a group other than a hydrogen atom, that is, a substituted aniline in which the ortho position is not a hydrogen atom, may be used. Since such a substituted aniline can undergo the Friedel-Crafts reaction only at the para position, it is incorporated into the terminal of the polyfunctional amine obtained in the polymerization step (the reaction of increasing the molecular weight is completed when the dialkene or diol reacts with the substituted aniline). Specific examples of such a substituted aniline include 2-methyl-6-ethylaniline and 2,6-dimethylaniline. By using such a substituted aniline to introduce an -NH2 group to the end of the polyfunctional amine obtained in the polymerization step, a maleimide compound (B) having a group represented by general formula (MI) also at the end can be produced.

[0132] In the maleimidation step, the polyfunctional amine having a plurality of partial structures represented by general formula (AM-2) obtained in the polymerization step is reacted with an acid anhydride represented by general formula (AA) to maleimidize the -NH2 group in the polyfunctional amine. The maleimidization is usually carried out using a solvent. Since the maleimidization reaction is a dehydration reaction, it is preferable to carry out the reaction while removing water from the reaction system, for example, by using a Dean-Stark apparatus. From the viewpoint of suppressing unintended side reactions, a polymerization inhibitor or stabilizer such as hydroquinone, hydroquinone monomethyl ether, or 4-tert-butylcatechol may be used in the maleimidization reaction. The reaction temperature in the maleimidization step is preferably 80 to 200° C., and the reaction time is preferably 1 to 24 hours.

[0133] It is preferable that impurities in the obtained product are reduced through procedures such as dilution of the reaction solution, precipitation using a poor solvent, and washing.

[0134] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. EXAMPLES

[0135] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. It should be noted that the present invention is not limited to the Examples.

[0136] <Synthesis of polyimide (A)> Polyimide (A-1) having a maleimide skeleton was synthesized according to the description of paragraph 0194 and Example 1 of WO 2022 / 270529. This polyimide (A-1) contained a structural unit represented by the following formula and had a dimethylmaleimide group at the end. This polyimide (B-1) had a weight average molecular weight Mw of 74,000, a polydispersity (weight average molecular weight Mw / number average molecular weight Mn) of 2.62, and a terminal blocking rate of 65%.

[0137] [ka]

[0138] <Synthesis of maleimide compound (B)> The maleimide compound (B-3) used in Examples 3 and 4 described later was synthesized according to the following procedure. (1) Synthesis of polyfunctional amines The following monomers: TPE-M, PXG, and 26DMA were mixed in a molar ratio of 125 / 100 / 50 to form a first mixture. To this mixture, p-toluenesulfonic acid monohydrate was further added to form a second mixture. The amount of p-toluenesulfonic acid monohydrate was 10% by mass relative to the amount of TPE-M and PXG. The second mixture was placed in a reaction vessel and heated with stirring at 180° C. for 6 hours. Incidentally, this heating caused the TPE-M and PXG, which were solid at room temperature, to melt. After the heating was completed, N-methylpyrrolidone (NMP) was added to the reaction vessel so that the solid content concentration was about 30% to stop the reaction. In this way, a solution containing a polyfunctional amine was obtained.

[0139] [ka]

[0140] (2) Synthesis of maleimide compounds (maleimidization) A mixed solution was prepared by adding the following MMMA, toluene (2.5 times the amount of NMP) and hydroquinone monomethyl ether (0.5% relative to the amount of the polyfunctional amine obtained in (1)) to the solution containing the polyfunctional amine obtained in (1). The amount of MMMA was 1.4 mol per 1 mol of amino groups in the polyfunctional amine. Thereafter, the mixture was heated using a Dean-Stark apparatus to carry out maleimidization (dehydration reaction) of the amino groups in the polyfunctional amine. The reaction temperature was adjusted between 120 and 170° C. while checking the reflux state. The reaction time (heating time) was 5 hours. After the reaction was completed, the reaction solution was diluted with acetone, and a precipitate was obtained using a poor solvent of isopropanol / water=4 / 1, and then the precipitate was dried at 50° C. overnight. In this manner, the maleimide compound (B-3) was synthesized.

[0141] [ka]

[0142] The maleimide compound (B-3) thus obtained was subjected to GPC analysis using polystyrene as a standard substance. As a result of the analysis, the weight average molecular weight of the maleimide compound was 14,400 and the polydispersity was 4.0.

[0143] For reference, the chemical structure of the maleimide compound (B-3) is shown below. The maleimide compound (B-3) having the following chemical structure was obtained by (i) confirming dehydration during the reaction, (ii) confirming the consumption of MMMA using GPC, and (iii) 1 This was achieved through the confirmation of peaks suggesting the formation of methylene chains using H-NMR.

[0144] [ka]

[0145] The maleimide compound (B-1) used in Example 1 was synthesized in accordance with the above (1) and (2), except that the monomers were the above TPE-M and the following m-DIPEB, and the following DMMA was used in the maleimide formation instead of the above MMMA. The weight average molecular weight of (B-1) was 2280, and the polydispersity was 1.4.

[0146] [ka]

[0147] For reference, the chemical structure of the maleimide compound (B-1) is shown below.

[0148] [ka]

[0149] The maleimide compound (B-2) used in Example 2 was synthesized in accordance with the above (1) and (2) except that the above TPE-M and PXG were used as monomers and DMMA was used instead of MMMA in the maleimide formation. The weight average molecular weight of (B-2) was 20200 and the polydispersity was 5.7.

[0150] For reference, the chemical structure of the maleimide compound (B-2) is shown below.

[0151] [ka]

[0152] <Preparation of Curable Composition> The above polyimide (A-1), maleimide compounds (B-1) to (B-3), photosensitizer, adhesion aid and solvent were mixed uniformly in the amounts described below to prepare a curable composition. The components other than the polyimide and the maleimide compound will be described in detail below.

[0153] Photosensitizers (C-1): 2,4-diethylthioxanthone (commercially available product) Adhesion aid (D-1) 3-Trimethoxysilylpropylsuccinic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-12-967C") ·solvent NMP: N-methylpyrrolidone GBL: gamma-butyrolactone

[0154] <Evaluation> (Solubility / Compatibility with other ingredients) The prepared curable compositions were visually observed. When the composition was transparent, it was rated as good, and when the composition was cloudy, it was rated as bad.

[0155] (Dielectric tangent) First, a cured film for measuring the dielectric tangent was prepared according to the following procedure. The curable composition prepared above was applied onto a substrate and dried at 120°C for 10 minutes to obtain a resin film. This resin film was exposed to PLA (800mJ) and then heated at 200°C for 120 minutes. In this way, a cured film having a film thickness of 100μm was obtained. The obtained cured film was peeled off from the substrate using a hydrofluoric acid solution, then thoroughly washed with water, and thoroughly dried.

[0156] After drying, the dielectric loss tangent of the cured film was measured at 10 GHz by a cavity resonator method.

[0157] (sensitivity) The prepared curable composition was applied onto an 8-inch silicon wafer using a spin coater. After application, the wafer was prebaked at 120° C. for 4 minutes on a hot plate in the atmosphere. This resulted in a coating film having a thickness of about 6.5 μm. This coating was irradiated with i-line through a mask with a 20 μm wide via pattern by using an i-line stepper (Nikon Corporation, NSR-4425i). After the irradiation, the substrate was spray-developed for 60 seconds using cyclopentanone as a developer, thereby dissolving and removing the unexposed areas to obtain a via pattern. The cross section of the obtained via pattern was observed using a tabletop SEM. The width at the midpoint between the bottom surface of the via pattern and the opening was taken as the via width. The sensitivity was evaluated based on the exposure dose E at which a pattern with a via width of 20 μm was opened.

[0158] The results were evaluated according to the following criteria: Excellent: Exposure E is 10 J / cm 2 below Good: Exposure E is 10 J / cm 2 Greater than 100J / cm 2 below Possible: Exposure E is 100J / cm 2 Greater than 1000J / cm 2 below

[0159] The composition and evaluation results are summarized in the table below.

[0160] [Table 1]

[0161] As shown in the above table, transparent and uniform compositions were obtained in Examples 1 to 4. This indicates that the polyimide or its precursor (A) had good compatibility with the maleimide compound (B). In addition, the dielectric tangents of the cured products of the curable compositions of Examples 1 to 4 were small. This indicates that the curable composition of the present embodiment can be preferably applied to, for example, the manufacture of high-frequency devices. [Explanation of symbols]

[0162] 30 Interlayer insulating film 32 Passivation film 34 Top layer wiring 40 Redistribution layer 42 Insulating layer 44 Insulating layer 46 Rewiring 50 UBM layers 52 Bump 100 Electronic Devices

Claims

1. A polyimide or a precursor thereof (A); A maleimide compound (B) having at least one aromatic ring structure and three or more maleimide groups; 1. A curable composition comprising:

2. 2. The curable composition according to claim 1, The maleimide compound (B) is a polymer having a weight average molecular weight of 2,000 to 100,000.

3. The curable composition according to claim 1 or 2, The maleimide compound (B) is a polymer having a weight average molecular weight of 2,000 to 50,000.

4. The curable composition according to claim 1 or 2, At least a part of the maleimide groups in the maleimide compound (B) is a group containing a maleimide skeleton represented by the following general formula (MI): 【Chemistry 1】 In the general formula (MI), Two R's １ are each independently a hydrogen atom or a monovalent organic group, and two R １ At least one of the groups is a monovalent organic group, * indicates a bond to another chemical structure.

5. The curable composition according to claim 4, The R １ wherein the monovalent organic group is a methyl group.

6. The curable composition according to claim 1 or 2, The maleimide compound (B) has a partial structure represented by the following general formula (I): 【Chemistry 2】 In general formula (I), R ＭＩ represents a maleimide skeleton-containing group, L represents a single bond or a divalent linking group; R represents a monovalent substituent; m is an integer of 1 or more, n is an integer of 0 or more, and m+n≦4.

7. The curable composition according to claim 1 or 2, A curable composition, wherein the polyimide or its precursor (A) has a maleimide group at one or both ends.

8. The curable composition according to claim 7, a curable composition, wherein at least a part of the maleimide groups present at one or both ends of the polyimide or its precursor (A) is a group containing a maleimide skeleton represented by the following general formula (MI): 【Chemistry 3】 In the general formula (MI), Two R's １ are each independently a hydrogen atom or a monovalent organic group, and two R １ At least one of the groups is a monovalent organic group, * indicates a bond to another chemical structure.

9. The curable composition according to claim 1 or 2, A curable composition, wherein the amount of the polyimide or its precursor (A) in the composition is 10 to 150 parts by mass per 100 parts by mass of the maleimide compound (B).

10. The curable composition according to claim 1 or 2, The curable composition further comprising one or both of a photosensitizer and a photoinitiator.

11. The curable composition according to claim 1 or 2, The curable composition further comprises an adhesion aid.

12. The curable composition according to claim 1 or 2, A curable composition comprising the polyimide or its precursor (A) and the maleimide compound (B) dissolved in an organic solvent as a varnish.

13. A cured product of the curable composition according to claim 1 or 2.

14. A cured product of the curable composition according to claim 13, A cured product having a dielectric tangent of 0.006 or less at a frequency of 10 GHz.

15. An electronic device comprising the cured product according to claim 13.

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