Polyamide-imide resin, resin composition, and semiconductor device

Abstract

A poly(amide-imide) resin comprising a structural unit (Ia) represented by the following formula and at least one structural unit selected from the group consisting of structural units (IIa), (IIb), and (IIc) represented by the following formulae. In the structural unit (Ia), the X moieties each independently represent a hydrogen atom or a substituent selected from the group consisting of halogen atoms, C1-C9 alkyl groups, C1-C9 alkoxy groups, and hydroxyalkyl groups. In the structural units (IIa), (IIb), and (IIc), the S moieties each independently represent a C1-C3 alkyl group, a is an integer of 0-4, b is an integer of 0-3, and c is an integer of 0-4.

Description

[Technical Field]

[0001] The present embodiment relates to a polyamide-imide resin containing a cardo-type fluorene skeleton, a resin composition containing the polyamide-imide resin, and a semiconductor device using the resin composition. [Background technology]

[0002] Carbon dioxide (CO2) emitted from various industrial equipment is one of the main causes of global warming. Therefore, there is a need to build a low-carbon society in order to solve the problem of global warming. One way to achieve a low-carbon society is to apply power semiconductors to industrial equipment to reduce power loss. Power semiconductors are also used in various applications such as automobiles, and demand for them is increasing. Examples of power semiconductors for automobiles include power cards, as well as TO, SOP, QFP, BGA, and CSP packages.

[0003] In recent years, particularly with the electrification of automobiles (EVs), the power density of power semiconductors has improved, and the operating temperature (Tj) of devices has risen. As a result, the temperature required for heat cycle testing has also risen. However, in conventional power semiconductors, peeling may occur between components, such as the interface between the resin encapsulation layer and the substrate or the semiconductor element, during a heat cycle test that assumes a higher operating temperature (higher Tj). Peeling between components in a semiconductor device can lead to failure, significantly reducing the reliability of the semiconductor device.

[0004] To address the need for higher Tj in power semiconductor devices, various studies have been conducted on the resin encapsulation material that constitutes the resin encapsulation layer. For example, development of resin encapsulation materials with excellent heat resistance has been underway, and resin encapsulation materials with glass transition temperatures exceeding 230°C exhibit excellent heat resistance even at high temperatures exceeding 200°C. However, as the resin hardens, adhesion to components decreases, which can lead to reduced reliability of the semiconductor device. In addition, peeling between components can occur during the reflow process when the device is mounted. Therefore, from the viewpoint of improving the reliability of semiconductor devices, a method for improving the adhesion between components in a semiconductor device is desired in order to suppress peeling between components during high-temperature heat cycle tests and reflow processes.

[0005] To address this issue, a method is known in which a primer layer made of a resin material is formed between components of a semiconductor device to improve adhesion between the components and thereby prevent peeling. For example, a method is being considered in which a primer layer made of a polyamide-imide resin is provided between a metal lead frame and an encapsulant to suppress peeling (Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-135061 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as the Tj of power semiconductor devices increases, the conditions required for reliability tests of semiconductor devices become stricter, and it is becoming difficult for conventional resin materials to fully satisfy these conditions. Therefore, from the perspective of providing highly reliable power semiconductors, there is a continuing need for the development of resin materials with excellent heat resistance that can prevent peeling between components even in high-temperature regions exceeding 250°C, for example.

[0008] Therefore, in view of the above-mentioned circumstances, the present invention provides a resin material that has excellent heat resistance, can improve adhesion between components, and can suppress the occurrence of peeling, and can be particularly suitably used as a material for forming a primer layer provided between components of a semiconductor device. [Means for solving the problem]

[0009] To prevent peeling between components during a heat cycle test in a high-temperature range, the resin material forming the primer layer preferably has a glass transition temperature (Tg) higher than the upper limit of the operating temperature (Tj) of the power semiconductor. It is generally known that resins soften and lose adhesion at temperatures above their Tg. Therefore, if the Tg of the resin is lower than the operating temperature of the power semiconductor, the heat resistance becomes insufficient, making it difficult to ensure adhesion between components. As a result, peeling may occur, for example, between the resin encapsulation layer and the substrate or semiconductor element.

[0010] The inventors have conducted extensive research into polyamide-imide resins and resin compositions thereof as resin materials, and have found that polyamide-imide resins having a cardo structure-type fluorene skeleton have a high Tg. Furthermore, they have found that when a primer layer is formed between components, such as a resin sealing layer and a substrate or a semiconductor element, using a polyamide-imide resin having the specific structural unit or a resin composition containing this resin, excellent adhesion between the components can be achieved, which led to the completion of the present invention.

[0011] That is, the embodiments of the present invention relate to the following: However, the present invention is not limited to the following embodiments, and various modifications can be made.

[0012] One embodiment relates to a polyamideimide resin comprising a structural unit (Ia) represented by the following formula and at least one selected from the group consisting of structural units (IIa), (IIb), and (IIc) represented by the following formulas: [ka] [ka]

[0013] In the above formula (Ia), each X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a hydroxyalkyl group. In the above formulas (IIa), (IIb), and (IIc), each S independently represents an alkyl group having 1 to 3 carbon atoms, a represents an integer of 0 to 4, b represents an integer of 0 to 3, and c represents an integer of 0 to 4.

[0014] The polyamideimide resin preferably further contains a structural unit (IIIa) represented by the following formula: [ka]

[0015] In the above formula (IIIa), each R independently represents a hydrogen atom or a substituent selected from the group consisting of an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a halogen atom, and n represents an integer of 1 to 6.

[0016] The polyamide-imide resin preferably has a linear expansion coefficient of 40 to 70 ppm / °C.

[0017] In the polyamideimide resin, the proportion of the structural unit (Ia) is preferably 20 mol % or more based on the total amount of the structural unit (Ia) and at least one selected from the group consisting of the structural units (IIa), (IIb), and (IIc).

[0018] The polyamide-imide resin preferably has a glass transition temperature of 250° C. or higher, and more preferably has a glass transition temperature of 300° C. or higher.

[0019] Another embodiment relates to a polyamideimide resin composition comprising the polyamideimide resin of the above embodiment and a solvent. The polyamideimide resin composition preferably further comprises a coupling agent.

[0020] Another embodiment relates to a semiconductor device including a substrate and a film formed using the polyamide-imide resin composition of the above embodiment. The semiconductor device preferably further includes a resin sealing layer. The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2021-34526, filed on March 4, 2021, the disclosure of which is incorporated herein by reference. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a resin material that has excellent heat resistance, can increase adhesion between components, and can suppress the occurrence of peeling at high temperatures, and can be suitably used as a material for forming a primer layer between components in a semiconductor device. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0024] <Polyamide-imide resin> In one embodiment, the polyamide-imide resin contains the structural unit (Ia) described below and at least one selected from the group consisting of structural units (IIa), (IIb), and (IIc). Details of each structural unit are as follows:

[0025] The structural unit (Ia) is represented by the following formula: [ka]

[0026] In the structural unit (Ia), X may be the same or different. Each X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a hydroxyalkyl group. The halogen atom may be a fluorine atom, a chlorine atom, or a bromine atom. The alkyl group and the alkoxy group may have a linear structure, a branched structure, or a cyclic structure.

[0027] In one embodiment, each X is preferably a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, or a halogen atom. The alkyl group is more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms. In one embodiment, each X is preferably a hydrogen atom.

[0028] The structural units (IIa), (IIb), and (IIc) are each represented by the following formula: [ka]

[0029] In the structural units (IIa), (IIb), and (IIc), each S independently represents an alkyl group having 1 to 3 carbon atoms, a represents an integer of 0 to 4, b represents an integer of 0 to 3, and c represents an integer of 0 to 4. The alkyl group may have either a linear or branched structure, but preferably has a linear structure. The alkyl group more preferably has 1 or 2 carbon atoms. When the alkyl group has a linear structure, particularly when it is an alkyl group having 1 or 2 carbon atoms, it tends to be easier to obtain a resin with a rigid structure. Forming a film using a resin with a rigid structure tends to make it easier to keep the coefficient of linear expansion (CTE) low. Keeping the CTE of the film low makes it easier to keep the CTE difference with other components small, for example, in the usage environment of a semiconductor device. As a result, for example, in a semiconductor device, stress generated by heat can be reduced, and the reliability of the semiconductor device tends to be easily improved.

[0030] In one embodiment, the structural units (IIa), (IIb), and (IIc) can be derived using a diamine compound or diisocyanate compound having a structure corresponding thereto. Specific examples of diamine compounds from which the structural units (IIa), (IIb), and (IIc) can be derived include, but are not limited to, the following. The amino group in the following compounds may be substituted with an isocyanate group. [ka]

[0031] [ka]

[0032] [ka]

[0033] In one embodiment, a in the structural unit (IIa) is preferably 0 to 3, more preferably 0 to 2, even more preferably 0 or 1, and most preferably 0. b in the structural unit (IIb) is preferably 0 to 2, more preferably 0 or 1, and most preferably 0. c in the structural unit (IIc) is preferably 0 to 3, more preferably 0 to 2, even more preferably 0 or 1, and most preferably 0. When the number of substituents in the structural units (IIa), (IIb), or (IIc) is smaller, particularly when they are unsubstituted (i.e., when a, b, or c is 0), it tends to be easier to obtain a resin with a rigid structure. By forming a film using a resin with a rigid structure, it tends to be easier to keep the coefficient of linear expansion (CTE) low. By keeping the CTE of the film low, it becomes easier to keep the CTE difference with other components small, for example, in the use environment of a semiconductor device. As a result, for example, in a semiconductor device, stress generated by heat can be reduced, and the reliability of the semiconductor device tends to be easily improved.

[0034] From the above viewpoint, in one embodiment, the polyamideimide resin preferably contains the structural unit (Ia) and at least one selected from the group consisting of the structural units (IIa-1), (IIb-1), and (IIc-1) represented by the following formula: Although not particularly limited, a structure in which two bonding sites (represented by "*") to other structural sites are in a para-position relationship with each other is more preferred.

[0035] [ka]

[0036] A polyamide-imide resin is a resin having an amide bond and an imide bond in its molecular skeleton, and can be obtained, for example, by reacting a diamine component or a diisocyanate component with an acid component such as a tricarboxylic acid anhydride. From this perspective, in one embodiment, a polyamide-imide resin containing the structural unit (Ia) and at least one of the structural units (IIa), (IIb), and (IIc) can be derived using a compound represented by the following formula (I) and at least one compound represented by the following formulas (IIA), (IIB), and (IIC). The structural unit (Ia) and the structural units (IIa), (IIb), and (IIc) correspond to residues obtained by removing the substituent Y (an amino group or an isocyanate group) from the compounds represented by the following formulas (I), (IIA), (IIB), and (IIC), respectively, and may be directly bonded to an amide bond site or an imide bond site in the resin structure.

[0037] [ka]

[0038] In the above formula (I), Y is an amino group (-NH2) or an isocyanate group (-NCO), and X is as explained above in the section (Ia).

[0039] [ka]

[0040] In the above formulas (IIA), (IIB), and (IIC), Y is an amino group (—NH) or an isocyanate group (—NCO), and S, a, b, and c are as previously described.

[0041] Specific examples of the compound represented by the formula (I) include 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, and 9,9-bis(4-amino-3-fluorophenyl)fluorene, etc. These can be suitably used as diamine compounds from which the structural unit (Ia) can be derived.

[0042] Specific examples of the compound represented by formula (IIA) include 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, and 3,3'-diaminodiphenylmethane, which can be suitably used as diamine compounds from which the structural unit (IIa-1) can be derived.

[0043] Specific examples of the compound represented by formula (IIB) include 1,5-naphthalenediamine and 1,8-naphthalenediamine, which can be suitably used as diamine compounds from which the structural unit (IIb-1) can be derived.

[0044] Specific examples of the compound represented by formula (IIC) include 1,3-phenylenediamine and 1,4-phenylenediamine, which can be suitably used as diamine compounds from which the structural unit (IIc-1) can be derived.

[0045] From the viewpoint of suppressing peeling between components at the operating temperature (Tj) or reflow temperature of the power semiconductor, the polyamide-imide resin preferably has a glass transition temperature higher than the upper limit of Tj or the reflow temperature. In this specification, the "glass transition temperature (Tg)" is a value obtained by using a thermomechanical analyzer to obtain a film obtained by applying a resin dissolved in a solvent and drying it by heating.

[0046] In one embodiment, a heat cycle test, which assumes a higher operating temperature (higher Tj) for power semiconductors, is performed at a temperature of 175°C or higher. Furthermore, the semiconductor mounting and reflow are performed at a high temperature of around 260°C. Therefore, in one embodiment, the Tg of the polyamide-imide resin is preferably 250°C or higher. The Tg of the polyamide-imide resin is more preferably 270°C or higher, even more preferably 290°C or higher, and even more preferably 300°C or higher.

[0047] Peeling between components during the reflow process when mounting a device occurs when the stress generated by the rapid evaporation of moisture contained in the device and the stress caused by the difference in linear expansion between the components exceed the adhesive force between the components. In one embodiment, from the viewpoint of suppressing peeling during the reflow process, the Tg of the polyamide-imide resin is preferably 300°C or higher, and more preferably 320°C or higher.

[0048] The polyamide-imide resin of the above embodiment can easily achieve a Tg of 250°C or higher. In the polyamide-imide resin of the above embodiment, the structural unit (Ia) has a backbone known as a cardo structure, which is believed to contribute to an increase in Tg. Additionally, the presence of structural units (IIa), (IIb), and (IIc) in the resin is believed to further increase Tg. Furthermore, when a film is formed using the polyamide-imide resin, the physical properties of the film, such as the CTE, modulus of elasticity, and adhesion to an adherend, tend to be easily adjustable. For example, by adjusting the compounding ratio of the structural unit (Ia) to the structural units (IIa), (IIb), and (IIc), the desired physical properties of the film, such as Tg, CTE, modulus of elasticity, and adhesion, can be easily obtained. As a result, when the polyamide-imide resin of the above embodiment is used as a constituent material of a semiconductor device, the reliability of the semiconductor device can be easily improved.

[0049] Generally, films made of resins with high Tg tend to have low flexibility. If the film has low flexibility, it will be unable to relieve stress generated within the semiconductor device and will be prone to peeling. From this perspective, in one embodiment, the polyamide-imide resin preferably contains a structural unit (IIIa) represented by the following formula: When the polyamide-imide resin of the above embodiment further contains the structural unit (IIIa), it is believed that flexibility is improved and a film with excellent flexibility can be easily obtained.

[0050] [ka]

[0051] In the structural unit (IIIa), each R independently represents a hydrogen atom or a substituent selected from the group consisting of an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a halogen atom. The halogen atom may be a fluorine atom, a chlorine atom, or a bromine atom. The alkyl group and the alkoxy group may have a linear structure, a branched structure, or a cyclic structure. In one embodiment, each R is independently preferably an alkyl group having 1 to 9 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms. n represents an integer of 1 to 6. n is preferably an integer of 2 to 4, and more preferably 3 or 4.

[0052] In one embodiment, the structural unit (IIIa) can be derived using a compound represented by the following formula (III): The structural unit (IIIa) corresponds to a residue obtained by removing the substituent Y (amino group or isocyanate group) from the compound represented by the following formula (III), and may be directly bonded to an amide bond site or an imide bond site in the resin structure. [ka]

[0053] In the above formula (III), Y is an amino group (-NH2) or an isocyanate group (-NCO), and R and n are as described above.

[0054] Specific examples of the compound represented by formula (III) above include 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane, 1,3-bis(2-aminoethyl)1,1,3,3-tetramethyldisiloxane, 1,3-bis(aminomethyl)1,1,3,3-tetramethyldisiloxane, 1,3-bis(4-aminobutyl)1,1,3,3-tetramethyldisiloxane, 1,3-bis(5-aminopentyl)1,1,3,3-tetramethyldisiloxane, and 1,3-bis(6-aminohexyl)1,1,3,3-tetramethyldisiloxane.

[0055] As described above, the polyamide-imide resin of the above embodiment is thought to be able to easily achieve both a high glass transition temperature (Tg) and flexibility of the resin by further containing the structural unit (IIIa) in addition to the combination of the structural unit (Ia) and at least one selected from the group consisting of the structural units (IIa), (IIb), and (IIc). Therefore, for example, when a primer layer provided between components of a semiconductor device contains the polyamide-imide resin of the above embodiment, excellent adhesion can be easily obtained even in various tests conducted in a high temperature range of 250°C or higher. Furthermore, when the constituent material of the power semiconductor device contains the polyamide-imide resin of the above embodiment, it is possible to prevent the resin from softening due to heat generated during operation, which would otherwise cause a decrease in adhesion. Therefore, the polyamide-imide resin of the above embodiment makes it possible to achieve high reliability in the power semiconductor device.

[0056] In the polyamide-imide resin, the proportion of the structural unit (Ia) relative to the total amount of structural units derived from the diamine component and / or diisocyanate component may be 10 mol% or more, 15 mol% or more, 18 mol% or more, 30 mol% or more, 40 mol% or more, 45 mol% or more, 55 mol% or more, 65 mol% or more, or 70 mol% or more. The proportion of the structural unit (Ia) may be 95 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, or 75 mol% or less. In one embodiment, the proportion of the structural unit (Ia) may be 10 to 95 mol%, preferably 15 to 95 mol%, more preferably 45 to 90 mol%, even more preferably 55 to 85 mol%, and still more preferably 65 to 80 mol%.

[0057] In one embodiment, the total amount of the structural unit (Ia) and at least one of the structural units (IIa), (IIb), and (IIc) derived from the diamine component and / or the diisocyanate component may be 70 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, or 100 mol%. In one embodiment, the total amount may be 95 mol% or less. In one embodiment, the proportion of the structural unit (Ia) may be 20 mol% or more, preferably 45 mol% or more, more preferably 50 mol% or more, even more preferably 80 mol% or more, and still more preferably 85 mol% or more, based on the total amount of the structural unit (Ia) and at least one selected from the group consisting of the structural units (IIa), (IIb), and (IIc).

[0058] On the other hand, the proportion of at least one of the structural units (IIa), (IIb), and (IIc) is preferably 10 mol% or more relative to the total amount of structural units derived from the diamine component and / or diisocyanate component. In one embodiment, the proportion may be preferably 10 to 80 mol%, more preferably 12 to 65 mol%, and even more preferably 15 to 50 mol%. Note that when the polyamideimide resin contains two or more of the structural units (IIa), (IIb), and (IIc), the proportion refers to the total proportion of these structural units.

[0059] In the polyamide-imide resin, the total amount of the structural units (Ia) and at least one of (IIa), (IIb), and (IIc) is preferably 35 mol % or more, more preferably 40 mol % or more, and even more preferably 45 mol % or more, based on the total amount of all structural units constituting the resin. Here, the proportion (mol %) of each structural unit is calculated from the number of moles of the monomer compound corresponding to each structural unit.

[0060] In another embodiment, the polyamideimide resin preferably further contains a structural unit (IIIa). In one embodiment, the proportion of the structural unit (IIIa) relative to the total amount of structural units derived from the diamine component and / or the diisocyanate component may be 20 mol% or less, 15 mol% or less, or 10 mol% or less. The proportion of the structural unit (IIIa) may be 2.5 mol% or more, 5.0 mol% or more, or 7.5 mol% or more. In the above embodiment, as structural units derived from the diamine component and / or diisocyanate component, the total amount of the structural unit (Ia), the proportion of at least one of the structural units (IIa), (IIb), and (IIc), and the proportion of the structural unit (IIIa) may be 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, or 100 mol%. In the above embodiment, the proportion of the structural unit (IIIa) may be preferably 2.5 to 20 mol %, more preferably 5 to 15 mol %, and even more preferably 7.5 to 10 mol %. By adjusting the proportion of the structural unit (IIIa) within the above range, the properties of the structural unit (Ia) and at least one of the structural units (IIa), (IIb), and (IIc) can be easily exhibited.

[0061] In still another embodiment, the polyamideimide resin may further contain, in addition to the structural unit (Ia), at least one selected from the group consisting of the structural units (IIa), (IIb), and (IIc), and, if necessary, the structural unit (IIIa), an additional structural unit other than these structural units. The additional structural units may be structural units derived from aromatic diamines or aromatic diisocyanates, aliphatic diamines or aliphatic diisocyanates, and alicyclic diamines or alicyclic diisocyanates, each having a structure different from the structural units (Ia), (IIa), (IIb), (IIc), and (IIIa). The proportion of such additional structural units is preferably 20 mol% or less based on the total amount of structural units derived from the diamine component and / or diisocyanate component. The proportion of the additional structural units is more preferably 10 mol% or less, and even more preferably 5 mol% or less.

[0062] Examples of aromatic diamines (diisocyanates) from which additional structural units can be derived include: 2,7-diaminofluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]-9H-fluorene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diamino-2,2'-biphenyldisulfonic acid, 3,4'-diaminodiphenyl ether, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-phenylenediamine, 2-chloro-1,4-phenylenediamine, 1,3-phenylenediamine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 3,6-diaminocarbazole, 4,4'-bis(4-aminophenoxy)biphenyl, 2-trifluoromethyl-1,4-diaminobenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)benzidine, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl ether, 4-aminophenyl sulfide, 4,4'-diamino-3,3'-dimethylbiphenyl, naphthalenediamine, Naphthalene diisocyanate is an example.

[0063] Examples of aliphatic diamines (diisocyanates) from which additional structural units can be derived include: 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-di(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 4,4'-methylenebis(cyclohexylamine), hexamethylenediamine, Hexamethylene diisocyanate is an example.

[0064] In one embodiment, when a diamine is used in producing a polyamide-imide resin, an anhydride of an aliphatic or aromatic tricarboxylic acid can be used. From the viewpoint of heat resistance, it is preferable to use an anhydride of an aromatic tricarboxylic acid. In one embodiment, for example, it is preferable to use an acid halide of trimellitic anhydride as the acid component. Among them, it is particularly preferable to use trimellitic anhydride chloride represented by the following formula (IV). [ka]

[0065] From the above viewpoint, in one embodiment, the polyamideimide resin preferably contains a structural unit represented by the following formula (IVa) that can be derived from a reaction between an acid halide of trimellitic anhydride and a diamine component. [ka] In one embodiment, the proportion of the structural units derived from the above formula (IV) is preferably 50 mol% or more, more preferably 75 mol% or more, and even more preferably 90 mol% or more, based on the total amount of structural units derived from the acid component. That is, in one embodiment, the content of the acid halide of trimellitic anhydride is preferably 50 mass% or more, more preferably 75 mass% or more, and even more preferably 90 mass% or more, based on the total mass of the acid component. In one embodiment, the proportion of the structural unit derived from the above formula (IV) with respect to the total amount of the acid component may be 100 mol %. That is, in one embodiment, the content of the acid halide of trimellitic anhydride may be 100 mass % based on the total mass of the acid component.

[0066] In one embodiment, the polyamideimide resin may be a resin obtained by using, as the diamine or diisocyanate component, a compound represented by formula (I) above and at least one compound selected from the group consisting of formulas (IIA), (IIB), and (IIC) above, and using, as the acid component, a compound represented by formula (IV) above. In another embodiment, the polyamideimide resin may be a resin obtained by further adding, as the diamine or diisocyanate component, a compound represented by formula (III) above. In yet another embodiment, the polyamideimide resin may be a resin obtained by further using, as the acid component, a compound represented by formula (IV) above and another acid component.

[0067] Examples of the acid component that can be used include the above-mentioned tricarboxylic acid anhydrides or acid halides thereof other than the compound represented by formula (IV), and tricarboxylic acids such as trimellitic acid. Further, examples of the acid component that can be used include tetracarboxylic acid dianhydrides such as pyromellitic anhydride and biphenyltetracarboxylic acid dianhydride, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid.

[0068] The weight-average molecular weight (Mw) of the polyamideimide resin is preferably in the range of 30,000 to 120,000. A polyamideimide resin having an Mw within the above range is likely to form a coating film of the preferred thickness described below during the coating process. The Mw of the polyamideimide resin is more preferably in the range of 35,000 to 110,000, and even more preferably in the range of 38,000 to 100,000. The "Mw" described in this specification is a value measured using gel permeation chromatography in terms of standard polystyrene.

[0069] From the viewpoint of workability during film formation, the polyamide-imide resin is preferably soluble in an organic solvent at room temperature. As used herein, "soluble in an organic solvent at room temperature" means that when an organic solvent is added to a resin and stirred, the resulting solution is visually observed at room temperature, and the solution is transparent without any precipitate or turbidity. Here, the "room temperature" may generally be in the range of 10°C to 40°C, and preferably in the range of 20°C to 30°C. In one embodiment, the "solution" refers to a solution obtained by adding 1 to 30 g of the resin powder to 100 mL of organic solvent, for example. The organic solvent will be described later.

[0070] (Method of producing polyamide-imide resin) The polyamideimide resin can be produced according to a known method, and is not particularly limited. The polyamideimide resin can be produced, for example, by reacting a diamine component and / or a diisocyanate component with an acid component. The diamine component, diisocyanate component, and acid component are as described above. The reaction can be carried out without a solvent or in the presence of an organic solvent. The reaction temperature is preferably in the range of 25°C to 250°C. The reaction time can be adjusted appropriately depending on the batch size, the reaction conditions used, etc.

[0071] The organic solvent (reaction solvent) used in producing the polyamide-imide resin is not particularly limited. Examples of usable organic solvents include ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane; cyclic ester (lactone) solvents such as γ-butyrolactone; acyclic ester solvents such as cellosolve acetate; ketone solvents such as cyclohexanone and methyl ethyl ketone; nitrogen-containing solvents such as N-methyl-2-pyrrolidone, dimethylacetamide, and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone; and aromatic hydrocarbon solvents such as toluene and xylene. These organic solvents may be used alone or in combination. In one embodiment, it is preferable to select and use an organic solvent capable of dissolving the resin to be produced, and it is preferable to use a polar solvent, which will be described later, for example, a nitrogen-containing solvent.

[0072] In one embodiment, the polyamide-imide resin can be produced by first preparing a precursor of the polyamide-imide resin by reacting an acid component with a diamine component, and then dehydrating and cyclizing the precursor to obtain the polyamide-imide resin. However, the method for cyclizing the precursor is not particularly limited, and any method known in the art can be used. For example, a thermal cyclization method in which dehydration and cyclization are performed by heating under atmospheric or reduced pressure, or a chemical cyclization method in which a dehydrating agent such as acetic anhydride is used in the presence or absence of a catalyst, can be used.

[0073] In the case of the thermal ring closure method, it is preferable to carry out the dehydration reaction while removing water generated in the reaction from the system. During the dehydration reaction, the reaction solution may be heated to 80°C to 400°C, preferably 100°C to 250°C. Alternatively, water may be removed azeotropically by using an organic solvent capable of forming an azeotrope with water, such as benzene, toluene, or xylene.

[0074] In the case of the chemical ring closure method, the reaction may be carried out in the presence of a chemical dehydrating agent at 0°C to 120°C, preferably 10°C to 80°C. Examples of the chemical dehydrating agent that can be used include acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and benzoic anhydride, and carbodiimide compounds such as dicyclohexylcarbodiimide. During the reaction, it is preferable to use in combination a substance that promotes the cyclization reaction, such as pyridine, isoquinoline, trimethylamine, triethylamine, aminopyridine, and imidazole.

[0075] The chemical dehydrating agent may be used in an amount of 90 to 600 mol % based on the total amount of the diamine components, and the cyclization reaction promoter may be used in an amount of 40 to 300 mol % based on the total amount of the diamine components. Dehydration catalysts may also be used, such as phosphorus compounds (e.g., triphenyl phosphite, tricyclohexyl phosphite, triphenyl phosphate, phosphoric acid, phosphorus pentoxide), and boron compounds (e.g., boric acid, boric anhydride).

[0076] In the production of polyamide-imide resin, the molar ratio of the acid component to the diamine component (diisocyanate component) is not particularly limited and can be adjusted so that the reaction proceeds without excess or deficiency. In one embodiment, from the viewpoint of the molecular weight and degree of crosslinking of the resulting polyamide-imide resin, the total amount of the diamine component is preferably 0.90 to 1.10 mol, more preferably 0.95 to 1.05 mol, and even more preferably 0.97 to 1.03 mol per 1.00 mol of the total amount of the acid component.

[0077] <Polyamide-imide resin composition> In one embodiment, a polyamide-imide resin composition (hereinafter sometimes referred to as a resin composition) contains the polyamide-imide resin of the above embodiment and a solvent. In this specification, the resin composition may also be referred to as a varnish. (solvent) The solvent is not particularly limited as long as it can dissolve the polyamideimide resin. The term "solvent capable of dissolving the polyamideimide resin" refers to a solvent that, when the temperature of the solvent is not particularly limited and a solution obtained by adding a polyamideimide resin powder to the solvent and stirring is visually observed, no precipitation or turbidity is observed and the entire solution is transparent. In one embodiment, the solvent constituting the resin composition may be the same as the reaction solvent used in producing the resin. In particular, it is preferable to use a polar solvent.

[0078] Examples of polar solvents include nitrogen-containing compounds such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, and 1,3-dimethyltetrahydro-2(1H)-pyrimidinone; sulfolane and dimethyl sulfoxide; lactones such as γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-heptalactone, α-acetyl-γ-butyrolactone, and ε-caprolactone; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone; acyclic esters such as cellosolve acetate; ethylene glycol, glycerin; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; triethylene glycol dimethyl ether; and triethylene glycol diethyl ether. tetraethylene glycol dialkyl ethers such as tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dipropyl ether, and tetraethylene glycol dibutyl ether; diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether; triethylene glycol monoalkyl ethers such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether; and tetraethylene glycol monoalkyl ethers such as tetraethylene glycol monomethyl ether and tetraethylene glycol monoethyl ether.

[0079] In one embodiment, the solvent is preferably at least one selected from the group consisting of diethylene glycol dimethyl ether, triethylene glycol, triethylene glycol dimethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, cyclopentanone, cyclohexanone, tetrahydrofuran, 1,4-dioxane, dibutyl ether, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, dimethylacetamide, N,N-dimethylformamide, ethylene carbonate, propylene carbonate, and propylene glycol methyl acetate. When two or more solvents are used in combination, they can be mixed in any ratio.

[0080] Among the above solvents, solvents with a relatively low boiling point are preferred from the viewpoint of film-forming properties, such as diethylene glycol dimethyl ether, triethylene glycol, and triethylene glycol dimethyl ether.

[0081] The amount of solvent in the resin composition can be adjusted appropriately in consideration of viscosity. Although not particularly limited, in one embodiment, the amount of solvent is preferably 500 to 3,500 parts by mass per 100 parts by mass of the total amount of resin in the resin composition. More preferably, the amount of solvent is 5,000 to 2,000 parts by mass per 100 parts by mass of the total amount of resin.

[0082] (additives) If necessary, additional components such as additives such as colorants and coupling agents, and resin modifiers may be added to the polyamideimide resin composition (varnish). When the polyamideimide resin composition contains additional components, the amount of the additional components is preferably 50 parts by mass or less per 100 parts by mass of the total amount of polyamideimide resin (solid components) in the polyamideimide resin composition. By setting the amount of the additional components to 50 parts by mass or less, it becomes easier to suppress deterioration in the physical properties of the resulting coating film.

[0083] In one embodiment, the polyamideimide resin composition may contain a coupling agent. Examples of usable additional components are listed below. (coupling agent) The coupling agent that can be used is not particularly limited, and may be any of silane-based, titanium-based, and aluminum-based, but silane-based coupling agents are most preferred.The silane-based coupling agent is not particularly limited, and examples thereof include vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptosilane, Tripropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltris[2-(2-methoxyethoxy)ethoxy]silane, N-methyl-3-aminopropyltrimethoxysilane, triaminopropyltrimethoxysilane, 3-4,5-dihydroimidazol-1-ylpropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyldimethoxysilane, 3-cyanopropyltriethoxysilane, hexamethyldisilazane, N,Examples of the alkylsilane include O-bis(trimethylsilyl)acetamide, methyltrimethoxysilane, methyltriethoxysilane, ethyltrichlorosilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, amyltrichlorosilane, octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltri(methacryloyloxyethoxy)silane, methyltri(glycidyloxy)silane, N-β(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, trimethylsilyl isocyanate, dimethylsilyl isocyanate, methylsilyl triisocyanate, vinylsilyl triisocyanate, phenylsilyl triisocyanate, tetraisocyanate silane, and ethoxysilane isocyanate. These may be used alone or in combination of two or more.

[0084] The titanium-based coupling agent is not particularly limited, and examples thereof include isopropyl trioctanoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctylphosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, isopropyl tris(n-aminoethyl)titanate, tetraisopropyl bis(dioctylphosphite) titanate, tetraoctyl bis(ditridecylphosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, dicumylphenyloxyacetate titanate, bis(dioctylpyrophosphate)oxyacetate titanate, tetraisopropyl titanate, tetraisopropyl bis(dioctylpyrophosphate)oxyacetate ... butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium ethylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium chiriethanolamine, polyhydroxytitanium stearate, tetramethyl orthotitanate, tetraethyl orthotitanate, tetrapropyl orthotitanate, tetraisobutyl orthotitanate, stearyl titanate, cresyl titanate monomer, cresyl titanate polymer, diisopropoxy-bis(2,4-pentadionato)titanium(IV), diisopropyl-bis-triethanolamino titanate, octylene glycol titanate, tetra-n-butoxytitanium polymer, tri-n-butoxytitanium monostearate polymer, tri-n-butoxytitanium monostearate, and the like. These may be used alone or in combination of two or more.

[0085] The aluminum coupling agent is not particularly limited, but examples thereof include aluminum chelate compounds such as ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetate bis(ethyl acetoacetate), aluminum tris(acetylacetonate), aluminum-monoisopropoxymonoleoxyethyl acetoacetate, aluminum-di-n-butoxide-mono-ethyl acetoacetate, and aluminum-di-isopropoxide-mono-ethyl acetoacetate, and aluminum alcoholates such as aluminum isopropylate, mono-sec-butoxyaluminum diisopropylate, aluminum-sec-butylate, and aluminum ethylate. These may be used alone or in combination of two or more.

[0086] In one embodiment, the viscosity of the polyamide-imide resin composition is preferably in the range of 10 mPa·s to 400 mPa·s, and more preferably in the range of 10 mPa·s to 300 mPa·s. Here, the viscosity is a value obtained by measuring a varnish dissolved in a solvent so that the nonvolatile components (solid components) are 1 to 20 mass% using an E-type viscometer at 10 rpm at 25°C. If the viscosity measured at 10 rpm is 10 mPa·s or more, it is easy to ensure a sufficient film thickness when applied. Furthermore, if the viscosity is 400 mPa·s or less, it is easy to ensure a uniform film thickness when applied. Therefore, by adjusting the viscosity within the above range, excellent printability can be easily obtained.

[0087] In one embodiment, from the viewpoint of obtaining excellent applicability, the viscosity is preferably greater than 50 mPa·s, and more preferably greater than 100 mPa·s. If the viscosity is too low, the composition may spread beyond the predetermined range, making it difficult to handle. The viscosity can be measured, for example, using a viscometer (RE type) manufactured by Toki Sangyo Co., Ltd. In the measurement, the measurement temperature is set to 25°C ± 0.5°C, and then 1 mL to 1.5 mL of the resin composition (varnish) is placed in the viscometer, and the viscosity is recorded 10 minutes after the start of the measurement.

[0088] In one embodiment, the thickness of the film formed from the resin composition is not particularly limited, but may be in the range of 0.5 to 50 μm. Having a thickness within this range tends to make it easier to ensure sufficient adhesion. From the above viewpoint, the film thickness is preferably in the range of 1 to 15 μm, and more preferably in the range of 3 to 15 μm.

[0089] In one embodiment, the elastic modulus at 35°C of a 10 μm-thick film obtained by applying and heat-drying a resin composition (varnish) is preferably in the range of 0.5 GPa to 8.0 GPa, more preferably in the range of 1.0 GPa to 5.0 GPa, and even more preferably in the range of 2.0 GPa to 4.5 GPa. The heat-drying to form the film can be performed, for example, under conditions of heating at 50°C for 10 minutes and then drying at 260°C for 1 hour. The elastic modulus is a value measured using a dynamic viscoelasticity measuring device. From the viewpoint of further improving the reliability of the power semiconductor device, it is preferable that the film have appropriate flexibility. Therefore, in one embodiment, the elastic modulus of the film is more preferably in the range of 3.0 GPa to 4.5 GPa.

[0090] The elastic modulus can be measured, for example, using a dynamic viscoelasticity measuring device "Rheogel-E4000" manufactured by UBM Co., Ltd. The elastic modulus is a value obtained by measuring, for example, a film obtained by applying and drying a resin composition (varnish) under conditions of a measurement frequency of 10 MHz and a measurement temperature of 35°C.

[0091] The resin composition of the above embodiment has excellent heat resistance and flexibility, and therefore can be suitably used as a constituent material of a semiconductor device. For example, the resin composition can be used to form an insulating layer, an adhesive layer, a protective layer, etc. in a semiconductor device, and a semiconductor device having these layers will have excellent adhesion between each member and excellent reliability. In one embodiment, the resin composition can be suitably used to form a primer layer provided between an encapsulant and a substrate, or between an encapsulant and a semiconductor element, in a semiconductor device. The adhesion between each member can be evaluated by shear strength.

[0092] In one embodiment, the shear strength between members having a primer layer made of the resin composition at 260°C is preferably 11 MPa or more, more preferably 15 MPa or more, and even more preferably 17 MPa or more. If the shear strength at 260°C is 11 MPa or more, it is easy to obtain excellent adhesion even when the resin composition is applied to a power semiconductor device.

[0093] In one embodiment, a laminate having a primer layer and a resin sealing layer, each composed of the resin composition, sequentially formed on a substrate can have a shear strength of 11 MPa or more between the substrate and the resin sealing layer at 260° C. The laminate can be obtained by applying a resin composition (varnish) to a substrate and drying it to form a film, and then forming a resin sealing layer thereon.

[0094] The shear strength can be measured using, for example, a shear strength measuring device (4000 Series manufactured by Nordson Advanced Technologies, Inc.). For example, a sample can be used for the measurement, in which a resin composition is applied to a Ni substrate and dried to form a film, and then a φ5 mm resin sealing layer is molded on top of the film using an epoxy-based sealing resin. Typical measurement conditions are a heat stage temperature of 260°C and a probe speed of 3 mm / min. The substrate material and the sealing material constituting the resin sealing layer can also be changed as appropriate. In the measurement, a Cu substrate may be used instead of the Ni substrate, or a Cu substrate plated with Ag may be used.

[0095] When the resin composition is used to form a primer layer between an encapsulant and a substrate, or between an encapsulant and a semiconductor element, in a semiconductor device, it is preferable that the difference in the coefficient of linear expansion (CTE) between each component and a film made of the resin composition be small, in order to suppress stress caused by thermal expansion and contraction and improve adhesion. From this perspective, in one embodiment, the coefficient of linear expansion (CTE) of the polyamide-imide resin is preferably in the range of 40 to 90 ppm / °C, more preferably in the range of 50 to 70 ppm / °C, and even more preferably in the range of 55 to 65 ppm / °C. Furthermore, the CTE of a resin composition containing a polyamide-imide resin is also preferably within the above range.

[0096] The CTE is a value measured using a film obtained by applying and drying a varnish of a resin or a resin composition. Measurements can be performed using, for example, a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation, "SS7100"). Measurement conditions can be a chuck distance of 10 mm, a load of 10 g, and a heating rate of 10°C / min. The CTE defined in this specification is a value calculated from the slope of a straight line connecting the values at 70°C and 140°C.

[0097] <Semiconductor device> One embodiment relates to a semiconductor device having a substrate and a dry film formed using the resin composition of the above embodiment. The components of the semiconductor device generally include a semiconductor element mounted on a substrate and a sealing member (sealing layer). The semiconductor element is typically made of inorganic materials such as semiconductor chips (Si, SiC, GaN), Cu, Ni plating, Ag plating, Au plating, Au / Pd / Ni plating, solder, sintered silver, sintered copper, Al wire, Au wire, and ceramic substrates (alumina, alumina zirconia, aluminum nitride, silicon nitride). The sealing layer is typically made of an organic material such as resin. Hereinafter, a sealing layer made of resin will be referred to as a resin sealing layer.

[0098] In the semiconductor device, by forming a dry film using the resin composition of the embodiment as a primer layer between each component, adhesion between the components can be easily improved. More specifically, for example, by forming a dry film of the resin composition between the resin encapsulation layer and the substrate, or between the resin encapsulation layer and the semiconductor element, adhesion between the components can be ensured and peeling during cycle testing can be prevented. From this perspective, in one embodiment, the semiconductor device includes a substrate, a semiconductor element mounted on the substrate, a primer layer provided on at least the semiconductor element mounting surface of the substrate, and a resin encapsulation layer provided on the primer layer, and the primer layer is preferably composed of a dry film formed using the resin composition for semiconductor devices of the embodiment. The substrate may be a lead frame composed of a die pad for mounting the semiconductor element and leads, and the electrode pads of the semiconductor element and the leads of the lead frame are electrically connected via wires.

[0099] In one embodiment, the resin composition can be suitably used as a constituent material of a power semiconductor device using the silicon carbide (SiC) substrate or the gallium nitride (GaN) substrate. When the resin composition is used to form a power semiconductor device, a decrease in adhesion between components during a heat cycle test can be easily suppressed.

[0100] A typical structure of the semiconductor device of the above embodiment will be specifically described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment of a semiconductor device. The semiconductor device shown in FIG. 1 has a die pad 1a, a semiconductor element 2, a primer layer 3, leads 1b, wires 4, and a resin encapsulation layer 5, and the primer layer 3 is formed from the resin composition of the above embodiment. As shown in FIG. 1, the primer layer 3 formed from the resin composition is provided on the semiconductor element mounting surface of the substrate 1 that contacts the resin encapsulation layer 5 (the surface of the lead 1b and the die pad 1a on which the semiconductor element 2 is mounted), thereby easily improving adhesion between the various components.

[0101] In one embodiment, a method for manufacturing a semiconductor device includes at least the steps of applying the resin composition of the above embodiment to the surface of a substrate carrying a semiconductor element and drying it to form a primer layer, and forming a resin sealing layer on the primer layer.

[0102] In the above embodiment, the primer layer is formed using the resin composition of the above embodiment. From the viewpoint of workability, it is preferable to use a resin composition (varnish) containing a polyamideimide resin as the resin component. The primer layer can be obtained by applying the resin composition to a predetermined location and drying the coating.

[0103] The material of the lead frame, which is composed of a die pad on which a semiconductor element is mounted and leads, is not particularly limited and can be selected from materials well known in the art. From the viewpoint of application to a power semiconductor device, the die pad material is preferably at least one selected from the group consisting of Ni and Cu. Furthermore, the one selected from the group consisting of Ni and Cu may have Ag plating on its surface. The lead material of the lead frame is preferably selected from the group consisting of Ni and Cu. The material of the semiconductor element is not particularly limited, and may be, for example, a silicon wafer, a silicon carbide wafer, or the like.

[0104] The resin encapsulation layer may be formed using an encapsulant known in the art. For example, the resin encapsulant may be a liquid or solid epoxy-based resin composition. The resin encapsulation layer may be formed by, for example, transfer molding using the resin encapsulant. In another embodiment, a method for manufacturing a semiconductor device includes, for example, a step of applying and drying the resin composition of the above embodiment to a semiconductor substrate on which multiple wirings of the same structure are formed to form a resin layer, and a step of forming rewiring on the resin layer, which is electrically conductive with the electrodes on the semiconductor substrate, as needed. In addition to the above steps, the method may also include a step of forming a protective layer (resin layer) on the rewiring or the resin layer using the resin composition of the above embodiment. Furthermore, in addition to the above steps, the method may also include a step of forming external electrode terminals on the resin layer, as needed, and then dicing as needed.

[0105] The method for applying the resin layer (primer layer) is not particularly limited, but is preferably spin coating, spray coating, or dispense coating. The resin layer can be dried by a method known in the art. The resin composition of the above embodiment also has excellent properties such as sputtering resistance, plating resistance, and alkali resistance, which are required in the process of forming rewiring. Therefore, the resin composition of the above embodiment can be suitably used as a material for any semiconductor device, without being limited to the configuration of the semiconductor device described above. [Example]

[0106] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples and includes various embodiments.

[0107] <1> Synthesis of polyamide-imide resin (Synthesis Example 1) A 1-liter four-neck flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a condenser with an oil-water separator was charged with 25.1 g of 9,9-bis(4-aminophenyl)fluorene, 3.6 g of 4,4'-diaminodiphenylmethane, and 2.5 g of 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane under a nitrogen stream, and 284 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) was added and dissolved to obtain a solution. Next, 21.1 g of trimellitic anhydride chloride (hereinafter referred to as TAC) was added to the above solution while cooling so that the temperature did not exceed 20° C. After stirring at room temperature for 2 hours, 12.1 g of triethylamine (hereinafter referred to as TEA) was added and the mixture was allowed to react at room temperature for at least 12 hours to obtain a polyamic acid solution. The resulting polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamideimide resin solution. This polyamideimide resin solution was poured into water, and the resulting precipitate was separated, crushed, and dried to obtain a powdered polyamideimide resin (PAI-1). The resulting polyamideimide resin powder (PAI-1) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight average molecular weight (Mw) of the obtained polyamideimide resin (PAI-1) was measured using gel permeation chromatography (hereinafter referred to as GPC) in terms of standard polystyrene, and was found to be 57,000 to 68,000.

[0108] The GPC measurement conditions are as follows: Liquid transfer pump: Shimadzu Corporation LC-20AD UV-Vis detector: Shimadzu Corporation SPD-20A, UV 270 nm Eluent: tetrahydrofuran / dimethylformamide = 1 / 1 (volume ratio) + 0.06M phosphoric acid + 0.06M lithium bromide Column: Hitachi High-Technologies Corporation Gel Pack GL-S300MDT-5 x 2 Column size: 8mm l.D x 300mm Sample concentration: 5mg / 1mL Flow rate: 1 mL / min Column temperature: 40°C Molecular weight standards: Standard polystyrene

[0109] (Synthesis Example 2) Powdered polyamideimide resin (PAI-2) was obtained in the same manner as in Synthesis Example 1, except that in the preparation of polyamideimide resin (PAI-1) described in Synthesis Example 1, the amount of 9,9-bis(4-aminophenyl)fluorene was changed to 15.7 g and the amount of 4,4'-diaminodiphenylmethane was changed to 8.9 g. The polyamideimide resin powder (PAI-2) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight average molecular weight (Mw) of the resulting polyamideimide resin (PAI-2) was measured in terms of standard polystyrene and found to be 72,000. The Mw was measured in the same manner as in Synthesis Example 1.

[0110] (Synthesis Example 3) Powdered polyamideimide resin (PAI-3) was obtained in the same manner as in Synthesis Example 1, except that in the preparation of polyamideimide resin (PAI-1) described in Synthesis Example 1, the amount of 9,9-bis(4-aminophenyl)fluorene was changed to 6.3 g and the amount of 4,4'-diaminodiphenylmethane was changed to 14.3 g. The polyamideimide resin powder (PAI-3) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight average molecular weight (Mw) of the resulting polyamideimide resin (PAI-3) was measured in terms of standard polystyrene and found to be 100,000. The Mw was measured in the same manner as in Synthesis Example 1.

[0111] (Synthesis Example 4) A 1-liter four-neck flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a condenser with an oil-water separator was charged with 15.7 g of 9,9-bis(4-amino-3-methylphenyl)fluorene, 7.1 g of 1,5'-diaminonaphthalene, and 2.5 g of 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane under a nitrogen stream, and 250 g of NMP was added and dissolved to obtain a solution. Next, 21.1 g of TAC was added to the above solution while cooling it so that the temperature did not exceed 20° C. After stirring at room temperature for 2 hours, 12.1 g of TEA was added and reacted at room temperature for at least 12 hours to produce a polyamic acid solution. The resulting polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamideimide resin solution. This polyamideimide resin solution was poured into water, and the resulting precipitate was separated, crushed, and dried to obtain a powdered polyamideimide resin (PAI-5). The polyamideimide resin powder (PAI-5) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight average molecular weight (Mw) of the obtained polyamideimide resin (PAI-5) was measured using GPC in terms of standard polystyrene and found to be 65,000. The Mw was measured in the same manner as in Synthesis Example 1.

[0112] (Synthesis Example 5) A 1-liter four-neck flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a condenser with an oil-water separator was charged with 15.7 g of 9,9-bis(4-amino-3-methylphenyl)fluorene, 4.9 g of 1,4-phenylenediamine, and 2.5 g of 1,3-bis(3-aminopropyl)1,1,3,3-tetramethyldisiloxane under a nitrogen stream, and 238 g of NMP was added and dissolved to obtain a solution. Next, 21.1 g of TAC was added to the above solution while cooling it so that the temperature did not exceed 20° C. After stirring at room temperature for 2 hours, 12.1 g of TEA was added and reacted at room temperature for at least 12 hours to produce a polyamic acid solution. The resulting polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamideimide resin solution. This polyamideimide resin solution was poured into water, and the resulting precipitate was separated, crushed, and dried to obtain a powdered polyamideimide resin (PAI-5). The polyamideimide resin powder (PAI-5) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight average molecular weight (Mw) of the obtained polyamideimide resin (PAI-5) was measured using GPC in terms of standard polystyrene and found to be 42,000. The Mw was measured in the same manner as in Synthesis Example 1.

[0113] (Synthesis Example 6) Under a nitrogen stream, 102.4 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 6.9 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane were placed in a 1-liter four-neck flask fitted with a thermometer, a stirrer, a nitrogen inlet tube, and a condenser equipped with an oil-water separator, and 700 g of NMP was added and dissolved to obtain a solution. Next, 59.0 g of TAC was added to the above solution while cooling the reaction solution so that it did not exceed 20° C. After stirring at room temperature for 1 hour, 34.0 g of TEA was added while cooling the reaction solution so that it did not exceed 20° C., and the mixture was allowed to react at room temperature for 3 hours to produce a polyamic acid solution. The resulting polyamic acid solution was further subjected to dehydration condensation at 190° C. for 6 hours to produce a polyamideimide resin solution. This polyamideimide resin varnish was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain a powdered polyamideimide resin (PAI-6). The weight average molecular weight (Mw) of the resulting polyamideimide resin (PAI-6) was measured using gel permeation chromatography (GPC) in terms of standard polystyrene, and was found to be 75,000. The Mw measurement was performed in the same manner as in Synthesis Example 1.

[0114] <2> Preparation of polyamide-imide resin composition In the following examples and comparative examples, polyamideimide resin compositions (primer varnishes for semiconductor devices) were prepared using the polyamideimide resin powders (PAI-1) to (PAI-6) prepared in the above Synthesis Examples 1 to 6, respectively.

[0115] Example 1 In a 0.5-liter four-neck flask, 12 g of the polyamideimide resin powder (PAI-1) obtained in Synthesis Example 1, 60.9 g of N-methyl-2-pyrrolidone, 26.1 g of butyl cellosolve acetate, and 1.2 g of a silane coupling agent (product name KBM-402 (3-glycidoxypropylmethyldimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.) were added under a nitrogen stream and stirred for 12 hours to obtain a yellow reaction mixture. The resulting yellow reaction mixture was loaded into a filter KST-47 (manufactured by Advantec Co., Ltd.) and filtered under pressure at a pressure of 0.3 MPa to obtain a primer varnish for semiconductor devices (P-1).

[0116] Example 2 A primer varnish for semiconductor devices (P-2) was prepared in the same manner as in Example 1, except that the polyamideimide resin powder (PAI-1) used in Example 1 was replaced with (PAI-2) obtained in Synthesis Example 2.

[0117] Example 3 A primer varnish for semiconductor devices (P-3) was prepared in the same manner as in Example 1, except that the polyamideimide resin powder (PAI-1) used in Example 1 was replaced with (PAI-3) obtained in Synthesis Example 3.

[0118] Example 4 A primer varnish for semiconductor devices (P-4) was prepared in the same manner as in Example 1, except that the polyamideimide resin powder (PAI-1) used in Example 1 was replaced with (PAI-4) obtained in Synthesis Example 4.

[0119] Example 5 A primer varnish for semiconductor devices (P-5) was prepared in the same manner as in Example 1, except that the polyamideimide resin powder (PAI-1) used in Example 1 was replaced with (PAI-5) obtained in Synthesis Example 5.

[0120] (Comparative Example 1) A primer varnish for semiconductor devices (P-6) was prepared in the same manner as in Example 1, except that the polyamideimide resin powder (PAI-1) used in Example 1 was changed to (PAI-6) obtained in Synthesis Example 6, and the solvent was changed to 35 g of N-methyl-2-pyrrolidone and 52 g of butyl cellosolve acetate.

[0121] <3> Evaluation of polyamide-imide resin composition (primer varnish for semiconductor devices) Various properties were evaluated as follows. (elastic modulus) The primer varnishes (P-1) to (P-6) for semiconductor devices obtained in Examples 1 to 5 and Comparative Example 1 were applied to a substrate using a bar coater and dried by heating to obtain a dried film having a thickness of 10 μm. The drying by heating to form the dried film was carried out under the conditions of heating at 50°C for 10 minutes, followed by drying at 260°C for 1 hour. The dry film obtained as described above was used as a measurement sample, and the following measurements were carried out. The measurement sample was placed in a dynamic viscoelasticity measuring device (Rheogel-E4000) manufactured by UBM Co., Ltd., and the elastic modulus of the polyamide-imide resin was measured. The measurement was performed at a chuck distance of 20 mm, a temperature of 35°C, and a measurement frequency of 10 MHz, and the measured value was taken as the elastic modulus. The measured values are shown in Table 1.

[0122] (glass transition temperature) The primer varnishes (P-1) to (P-6) for semiconductor devices obtained in Examples 1 to 5 and Comparative Example 1 were applied to a substrate using a bar coater and dried by heating to obtain a dried film having a thickness of 10 μm. The drying by heating to form the dried film was carried out under the conditions of heating at 50°C for 10 minutes, followed by drying at 260°C for 1 hour. The dried film obtained as described above was used as a measurement sample and the following measurements were carried out. The measurements were carried out using a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation "SS7100") under the conditions of a chuck distance of 10 mm, a load of 10 g, and a heating rate of 10 °C / min. The inflection point from α1 to α2 in the linear expansion coefficient obtained by the TMA measurement was taken as the glass transition temperature.

[0123] (coefficient of linear expansion) The primer varnishes (P-1) to (P-6) for semiconductor devices obtained in Examples 1 to 5 and Comparative Example 1 were applied to a substrate using a bar coater and dried by heating to obtain a dried film having a thickness of 10 μm. To form the dried film, the coating was heated at 50°C for 10 minutes, and then dried at 260°C for 1 hour. The dry film obtained as described above was used as a measurement sample to measure the coefficient of linear expansion (CTE). The measurement was carried out using a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation "SS7100") under the conditions of a chuck distance of 10 mm, a load of 10 g, and a heating rate of 10 ° C / min. The displacements at 70 ° C and 140 ° C were connected by a straight line, and the value calculated from the slope was used as the CTE value.

[0124] (Adhesion (shear strength)) The primer varnishes for semiconductor devices (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were evaluated for adhesion using a 4000 series shear strength measuring device manufactured by Arctec Corporation. Specifically, the primer varnish was first applied to a Ni substrate using a spray coating device (model number: SV91) manufactured by Sanei Tech Co., Ltd., and then heated and dried to obtain a dried film with a thickness of 10 μm. Next, a resin sealing layer having a diameter of 5 mm was molded on the dried film to obtain a measurement sample. The sealing material used was an epoxy sealing resin (CEL-420HFC) manufactured by Showa Denko Materials Co., Ltd. The obtained measurement sample was placed on the heat stage of a 4000 series shear strength measurement device manufactured by Arctec Co., Ltd., and the shear strength was measured. The measurement was carried out at a temperature of 260°C and a probe speed of 3 mm / min. The results are shown in Table 1.

[0125] The adhesion in the high temperature range was evaluated based on the results of the shear strength measurement at 260°C according to the following criteria. The evaluation results are shown in Table 1. <Adhesion standards in high temperature ranges> A: The shear strength at 260°C is 18.0 MPa or more. B: The shear strength at 260°C is 11 MPa or more and less than 18.0 MPa. C: The shear strength at 260°C is less than 11 MPa.

[0126] (Reliability evaluation (moisture absorption reflow test)) The primer varnishes for semiconductor device (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were subjected to a moisture absorption reflow test. Specifically, a package was first assembled with a Cu lead frame and a Si chip mounted on it, and then the primer varnish was applied and dried using a spray coating device (model number: SV91) manufactured by Sanei Tech Co., Ltd. The drying conditions were a temperature of 260°C and a drying time of 1 hour. Next, a resin sealing layer was formed on the dried film using a sealing material manufactured by Showa Denko Materials Co., Ltd. under the product name "CEL-8240" to obtain a sample for evaluation. Next, the obtained evaluation sample was subjected to a moisture absorption reflow test under the following conditions. Moisture absorption conditions: JEDEC MSL 1 (85℃ / 85%RH x 168 hours), Reflow conditions: 260°C / 10 seconds x 3 times

[0127] Next, the semiconductor devices were observed using a high-precision ultrasonic microscope (C-SAM) before and after a reliability test (moisture absorption reflow test) to check for peeling between the resin encapsulation layer, the dried resin film (primer layer), and the lead frame. The results are shown in Table 1. The evaluation results of the reliability test shown in Table 1 are shown as the number of samples in which peeling was confirmed (numerator) relative to the total number of samples evaluated (denominator). The observation conditions were as follows: Equipment: High-precision ultrasonic microscope (C-SAM), Sonoscan D9600, frequency 30MHz Conditions: Room temperature (25°C ± 5°C), pure water used.

[0128] The results of the evaluation of each characteristic in Examples 1 to 5 and Comparative Example 1 are summarized in Table 1. [Table 1]

[0129] In Table 1, diamine-derived structural units I'-II' are structural units derived from 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0130] As described above, the resin compositions of the present invention (Examples 1 to 5) were able to obtain excellent adhesion even under high-temperature conditions of 260°C. On the other hand, the resin composition of Comparative Example 1 had a lower Tg than Examples 1 to 5, and showed significantly poor results in adhesion tests under high-temperature conditions of 260°C. The resin composition of Comparative Example 1 uses a polyamideimide resin that does not have a cardo structure-type fluorene skeleton. Furthermore, the results of the reliability test by the moisture absorption reflow test in Examples 1 to 3 show that Tg can be easily increased by adjusting the ratio of the structural unit (Ia) and the structural unit (IIa). Furthermore, as seen in Examples 1, 4, and 5, when Tg exceeds 300°C, not only is excellent adhesion under high temperature conditions obtained, but also good results are obtained in the moisture absorption reflow test, making it easy to improve reliability. From the above, it can be seen that according to the present invention, by having a polyamide-imide resin that has a combination of a structural unit having a cardo structure-type fluorene skeleton and a specific structural unit, it is possible to provide a resin and a resin composition that have excellent adhesion in high temperature regions and can improve the reliability of semiconductor devices. [Explanation of symbols]

[0131] 1 Lead frame, Cu substrate 1a Die Pad 1b lead 2. Semiconductor elements 3. Primer layer (resin composition film) 4 wire 5 Resin sealing layer

Claims

1. A polyamide-imide resin composition used as a primer layer-forming material to be provided between components of a semiconductor device, the polyamide-imide resin composition comprising a polyamide-imide resin obtained using a diamine component and / or a diisocyanate component and an acid component, and a solvent, the polyamide-imide resin contains, relative to the total amount of structural units derived from the diamine component and / or diisocyanate component, 10 to 80 mol % of structural units (Ia) represented by the following formula, 10 to 80 mol % of structural units (IIa) represented by the following formula, and 7.5 to 10 mol % of structural units (IIIa) represented by the following formula, and further contains structural units (IVa) represented by the following formula: The polyamideimide resin composition has a linear expansion coefficient of 40 to 70 ppm / °C. 【Chemical 1】 [In formula (Ia), each X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a hydroxyalkyl group.] 【Chemistry 2】 [In formula (IIa), each S independently represents an alkyl group having 1 to 3 carbon atoms, and a represents an integer of 0 to 4.] 【Chemistry 3】 [In formula (IIIa), each R independently represents a hydrogen atom or a substituent selected from the group consisting of an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a halogen atom, and n represents an integer of 1 to 6.] 【Chemistry 4】

2. 2. The polyamideimide resin composition according to claim 1, wherein in formula (Ia), each X independently represents a hydrogen atom or a substituent selected from the group consisting of an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and a hydroxyalkyl group.

3. 3. The polyamideimide resin composition according to claim 1, wherein the polyamideimide resin is composed of the structural unit (Ia), the structural unit (IIa), the structural unit (IIIa), and the structural unit (IVa).

4. The polyamideimide resin composition according to any one of claims 1 to 3, wherein the polyamideimide resin composition has a modulus of elasticity at 35°C when formed into a film of 3.0 to 4.5 GPa.

5. The polyamideimide resin composition according to any one of claims 1 to 4, which has a glass transition temperature of 250°C or higher.

6. The polyamideimide resin composition according to any one of claims 1 to 5, which has a glass transition temperature of 300°C or higher.

7. The polyamideimide resin composition according to any one of claims 1 to 6, wherein the polyamideimide resin has a weight average molecular weight of 30,000 to 120,000.

8. 8. The polyamideimide resin composition according to claim 7, wherein the weight average molecular weight of the polyamideimide resin is 57,000 to 120,000.

9. A semiconductor device comprising a substrate and a film formed using the polyamideimide resin composition according to any one of claims 1 to 8.

10. The semiconductor device according to claim 9 , further comprising a resin sealing layer.

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