Polyamide-imide resin, resin composition, and semiconductor device

Abstract

To provide a resin material suitable as a primer layer-forming material provided between members of a semiconductor device.SOLUTION: The present invention provides a polyamide-imide resin prepared by the use of a diamine component and / or a diisocyanate component, and an acid component, wherein the resin contains a structural unit (Ia), at least one selected from structural units (IIb) and (IIc), a structural unit (IIIa) having a siloxane, and a structural unit derived from a diamine component and / or a diisocyanate component different from said structural units.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This embodiment relates to a polyamideimide resin containing a cardo-structured fluorene skeleton. Further, this embodiment relates to a resin composition containing the above polyamideimide resin, and a semiconductor device using the resin composition.

Background Art

[0002] Carbon dioxide (CO2) emitted from various industrial equipment and the like is cited as one of the main causes of global warming. Therefore, in order to solve the global warming problem, the construction of a low-carbon society is required. As one method of realizing a low-carbon society, applying a power semiconductor to industrial equipment to reduce power loss can be mentioned. Power semiconductors are also applied to various uses such as automobiles, and their demand is increasing. Examples of power semiconductors for automobiles include power cards, and packages such as TO, SOP, QFP, BGA, and CSP.

[0003] In recent years, particularly with the electrification (EV conversion) of automobiles, the power density of power semiconductors has been improved, and the driving temperature (Tj) of devices has been rising. Therefore, the temperature required during the heat cycle test has also been increasing. However, in a heat cycle test assuming a high driving temperature (high Tj) of a conventional power semiconductor, peeling may occur between members such as the interface between the resin sealing layer and the substrate or the semiconductor element. When peeling occurs between members in a semiconductor device, it leads to a failure, so the reliability of the semiconductor device is significantly reduced.

[0004] To address the increasing Tj (transistor junction) of power semiconductor devices, various studies are being conducted from the perspective of resin encapsulants that constitute the resin encapsulation layer. For example, the development of resin encapsulants with excellent heat resistance is progressing, and resin encapsulants with a glass transition temperature exceeding 230°C exhibit excellent heat resistance even in high-temperature regions exceeding 200°C. However, on the other hand, as the resin hardens, the adhesion to components decreases, which can easily reduce the reliability of the semiconductor device. In addition, delamination between components may occur during the reflow process when mounting devices. Therefore, from the viewpoint of improving the reliability of semiconductor devices, there is a need for methods to improve the adhesion between components in semiconductor devices in order to suppress delamination between components during high-temperature heat cycle tests and reflow processes.

[0005] In response to this, a method is known to prevent delamination by forming a primer layer using a resin material between the components of a semiconductor device to improve the adhesion between each component. For example, a method has been investigated in which a primer layer using polyamide-imide resin is provided between a metal lead frame and a encapsulant to suppress the occurrence of delamination (Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-135061 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, with the increasing Tj of power semiconductor devices, the requirements for reliability testing of semiconductor devices have become more stringent, and it is becoming difficult to adequately satisfy these requirements with conventional resin materials. Therefore, from the perspective of providing highly reliable power semiconductors, there is a continuing need for the development of heat-resistant resin materials that can prevent delamination between components even in high-temperature regions exceeding 250°C.

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

[0009] From the viewpoint of improving delamination between components in high-temperature heat cycle tests, it is preferable that the resin material forming the primer layer has a glass transition temperature (Tg) higher than the upper limit of the power semiconductor's operating temperature (Tj). Generally, it is known that resins soften and their adhesion decreases at temperatures exceeding their Tg. Therefore, if the resin's Tg is lower than the power semiconductor's operating temperature, the heat resistance becomes insufficient, making it difficult to ensure adhesion between components. As a result, delamination may occur, for example, between the resin encapsulation layer and the substrate or semiconductor element.

[0010] The inventors conducted extensive research on polyamide-imide resins and their resin compositions as resin materials and found that polyamide-imide resins having a cardo-structured fluorene skeleton have a high Tg. Furthermore, they discovered that when a primer layer is formed between components, such as between a resin encapsulation layer and a substrate or semiconductor element, using a polyamide-imide resin having the above-mentioned specific structural unit or a resin composition containing this resin, excellent adhesion between components can be obtained, thus completing the present invention.

[0011] In other words, 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 polyamide-imide 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), X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, a C1-C9 alkyl group, a C1-C9 alkoxy group, and a hydroxyalkyl group. In the above equations (IIa), (IIb), and (IIc), S independently represents an alkyl group having 1 to 3 carbon atoms, a represents an integer from 0 to 4, b represents an integer from 0 to 3, and c represents an integer from 0 to 4.

[0014] The above polyamide-imide resin preferably further contains structural unit (IIIa) represented by the following formula. [ka]

[0015] In the above formula (IIIa), R independently represents a hydrogen atom or a substituent selected from the group consisting of C1-C9 alkyl groups, C1-C9 alkoxy groups, and halogen atoms, and n represents an integer from 1 to 6.

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

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

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

[0019] Another embodiment relates to a polyamide-imide resin composition containing the polyamide-imide resin of the above embodiment and a solvent. The above polyamide-imide resin composition preferably further contains 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 above semiconductor device preferably further has a resin sealing layer.

Advantages of the Invention

[0021] According to the present invention, there is provided a resin material that is excellent in heat resistance, can enhance the adhesion between members and suppress the occurrence of peeling at high temperatures, and can be suitably used as a primer layer forming material between members in a semiconductor device.

Brief Description 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.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0024] <Polyamide-imide Resin> In one embodiment, the polyamide-imide resin contains a 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.

Chemical Formula

[0026] In the above structural unit (Ia), X may be the same or different from each other. Each X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, a C1-C9 alkyl group, a C1-C9 alkoxy group, and a hydroxyalkyl group. The halogen atom may be a fluorine atom, a chlorine atom, or a bromine atom. The alkyl group and alkoxy group may be linear, branched, or cyclic.

[0027] In one embodiment, 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, X is preferably a hydrogen atom.

[0028] Structural units (IIa), (IIb), and (IIc) are represented by the following formulas, respectively. [ka]

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

[0030] In one embodiment, the above structural units (IIa), (IIb), or (IIc) can be derived using a diamine compound or diisocyanate compound having the corresponding structure. While not particularly limited, specific examples of diamine compounds capable of deriving the above structural units (IIa), (IIb), and (IIc) are listed below. The amino groups shown in the following compounds may be substituted with isocyanate groups. [ka]

[0031] [ka]

[0032] [ka]

[0033] In one embodiment, in structural unit (IIa), a is preferably 0 to 3, more preferably 0 to 2, even more preferably 0 or 1, and most preferably 0. In structural unit (IIb), b is preferably 0 to 2, more preferably 0 or 1, and most preferably 0. In structural unit (IIc), c 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 above structural units (IIa), (IIb), or (IIc) is smaller, especially when they are unsubstituted (i.e., a, b, or c is 0), it tends to be easier to obtain a rigid resin. By forming a film using a rigid resin, it tends to be easier to keep the coefficient of thermal expansion (CTE) low. By keeping the CTE of the film low, it becomes easier to minimize the CTE difference with other components, for example, in the operating environment of a semiconductor device. As a result, for example, in a semiconductor device, the 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 polyamide-imide resin preferably comprises 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 the two bonding sites (represented by "*") with other structural sites are in a para relationship with each other is more preferable.

[0035] [ka]

[0036] Polyamide-imide resins are resins having amide bonds and imide bonds in their molecular skeleton, and can be obtained, for example, by the reaction of a diamine component or a diisocyanate component with an acid component such as a tricarboxylic acid anhydride. From this viewpoint, in one embodiment, a polyamide-imide resin comprising the above structural unit (Ia) and at least one of the above 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). Structural unit (Ia) and structural units (IIa), (IIb), and (IIc) correspond to residues obtained by removing substituent Y (amino group or 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 structure of the resin.

[0037] [ka]

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

[0039] [ka]

[0040] In the above formulas (IIA), (IIB), and (IIC), Y is an amino group (-NH2) or an isocyanate group (-NCO). S, a, b, and c are as previously explained.

[0041] Specific examples of compounds represented by formula (I) above 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. These can be suitably used as diamine compounds from which structural unit (Ia) can be derived.

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

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

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

[0045] The polyamide-imide resin preferably has a glass transition temperature higher than the upper limit of the power semiconductor's operating temperature (Tj) or reflow temperature, for example, from the viewpoint of suppressing delamination between components at the power semiconductor's operating temperature (Tj) or reflow temperature. In this specification, "glass transition temperature (Tg)" refers to a value obtained using a thermomechanical analyzer with a film obtained by coating and heat-drying a resin dissolved in a solvent.

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

[0047] Delamination between components during the reflow process when mounting a device occurs when stress caused by the rapid vaporization of moisture contained in the device and stress due to differences in linear expansion between components exceed the adhesion force between components. In one embodiment, from the viewpoint of suppressing delamination 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 makes it easy to obtain a Tg of 250°C or higher. In the polyamide-imide resin of the above embodiment, structural unit (Ia) is thought to contribute to the increase in Tg by having a skeleton known as a cardi structure. In addition, it is presumed that the presence of structural units (IIa), (IIb), and (IIc) in the resin makes it possible to further increase Tg. Furthermore, when a film is formed using the polyamide-imide resin, the physical properties of the film, such as CTE, elastic modulus, and adhesion to the adherend, tend to be easily adjusted. For example, by adjusting the mixing ratio of structural unit (Ia) and structural units (IIa), (IIb), and (IIc), desired physical properties of the film, such as Tg, CTE, elastic modulus, and adhesion, can be easily obtained. As a result, when the polyamide-imide resin of the above embodiment is used as a constituent material for a semiconductor device, it becomes easy to improve the reliability of the semiconductor device.

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

[0050] [ka]

[0051] In structural unit (IIIa), R independently represents a hydrogen atom or a substituent selected from the group consisting of a C1-C9 alkyl group, a C1-C9 alkoxy group, and a halogen atom. The halogen atom may be a fluorine atom, a chlorine atom, or a bromine atom. The alkyl group and alkoxy group may be linear, branched, or cyclic. In one embodiment, R is 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 between 1 and 6. Preferably, n is an integer between 2 and 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). Structural unit (IIIa) corresponds to a residue obtained by removing 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 equation (III) above, Y is an amino group (-NH2) or an isocyanate group (-NCO), and R and n are as previously explained.

[0054] Specific examples of compounds 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 easily achieve both a high glass transition temperature (Tg) and flexibility by having a structural unit (IIIa) in addition to a combination of structural unit (Ia) and at least one selected from the group consisting of structural units (IIa), (IIb), and (IIc). For example, if the primer layer provided between each component of a semiconductor device contains the polyamide-imide resin of the above embodiment, excellent adhesion can be easily obtained even in tests conducted in high-temperature regions of 250°C or higher. Furthermore, when the constituent material of a power semiconductor device includes the polyamide-imide resin of the above embodiment, it is possible to suppress the softening of the resin due to heat generated during operation, which can lead to a decrease in adhesion. Therefore, the polyamide-imide resin of the above embodiment makes it possible to obtain high reliability in a power semiconductor device.

[0056] In polyamide-imide resins, the proportion of structural units (Ia) relative to the total amount of structural units derived from diamine and / or diisocyanate components 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 structural units (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 above 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 even more preferably 65 to 80 mol%.

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

[0058] On the other hand, the proportion of at least one structural unit consisting of (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 above proportion is preferably 10 to 80 mol%, more preferably 12 to 65 mol%, and even more preferably 15 to 50 mol%. Note that if the polyamide-imide resin contains two or more structural units (IIa), (IIb), and (IIc), the above proportion refers to their total proportion.

[0059] In polyamide-imide resins, the sum of the proportion of structural unit (Ia) and the proportion of at least one of (IIa), (IIb), and (IIc), based on the total amount of all structural units constituting the resin, is preferably 35 mol% or more, more preferably 40 mol% or more, and even more preferably 45 mol% or more. 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 other embodiments, the polyamide-imide resin preferably further contains structural unit (IIIa). In one embodiment, the proportion of structural unit (IIIa) relative to the total amount of structural units derived from the diamine component and / or diisocyanate component may be 20 mol% or less, 15 mol% or less, or 10 mol% or less. The proportion of 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, the sum of the proportion of structural unit (Ia), the proportion of at least one of structural units (IIa), (IIb), and (IIc), and the proportion of structural unit (IIIa) as structural units derived from the diamine component and / or diisocyanate component 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 structural unit (IIIa) may preferably be 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 structural unit (IIIa) to the above range, the properties of structural unit (Ia) and at least one of the above structural units (IIa), (IIb), and (IIc) can be easily expressed.

[0061] In yet another embodiment, the polyamide-imide resin may further include additional structural units other than those described above, in addition to structural unit (Ia), at least one selected from the group consisting of structural units (IIa), (IIb), and (IIc), and structural unit (IIIa) as needed. The additional structural units may be aromatic diamines or aromatic diisocyanates, aliphatic diamines or aliphatic diisocyanates, and alicyclic diamines or alicyclic diisocyanates, having structures different from the above structural units (Ia), (IIa), (IIb), (IIc), and (IIIa). The proportion of such additional structural units is preferably 20 mol% or less, relative to the total amount of structural units derived from the diamine component and / or diisocyanate component. The proportion of the above additional structural units is more preferably 10 mol% or less, and even more preferably 5 mol% or less.

[0062] As an example of an aromatic diamine (diisocyanate) from which additional structural units can be derived, 2,7-diaminofluorene, 9,9-Bis[4-(4-aminophenoxy)phenyl]-9H-fluorene, 2,2'-Ditrifluoromethyl-4,4'-Diaminobiphenyl, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 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 one example.

[0063] As an example of an aliphatic diamine (diisocyanate) from which additional structural units can be derived, 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 one example.

[0064] In one embodiment, when a diamine is used in the production of the polyamide-imide resin, an aliphatic or aromatic tricarboxylic acid anhydride can be used. From the viewpoint of heat resistance, it is preferable to use an aromatic tricarboxylic acid anhydride. In one embodiment, for example, it is preferable to use an acid halide of trimellitic anhydride as the acid component. Among these, 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 polyamide-imide resin preferably contains a structural unit represented by the following formula (IVa) that can be derived from the reaction of an acid halide of trimellitic anhydride with a diamine component. [ka] In one embodiment, the proportion of structural units derived from formula (IV) above 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 acid halides in trimellitic anhydride is preferably 50% by mass or more, more preferably 75% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the acid component. In one embodiment, the proportion of structural units derived from formula (IV) above to the total amount of acid components may be 100 mol%. That is, in one embodiment, the content of acid halides in trimellitic anhydride may be 100% by mass, based on the total mass of acid components.

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

[0067] The acid components that can be used may include, for example, the above tricarboxylic acid anhydrides or their acid halides other than the compound represented by formula (IV) above, and tricarboxylic acids such as trimellitic acid. In addition, tetracarboxylic acid dianhydrides such as pyromellitic acid 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 may be used as acid components.

[0068] The weight-average molecular weight (Mw) of the polyamide-imide resin is preferably in the range of 30,000 to 120,000. Polyamide-imide resins having an Mw within the above range are more likely to form a coating film of a preferred thickness, as described later, during the coating process. The Mw of the polyamide-imide 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 herein is a value measured using gel permeation chromatography on a standard polystyrene basis.

[0069] The above polyamide-imide resin is preferably soluble in an organic solvent at room temperature, from the viewpoint of workability during film formation. In this specification, "soluble in an organic solvent at room temperature" means that when the solution obtained by adding an organic solvent to the resin and stirring is observed visually at room temperature, there is no precipitate, no turbidity, and the entire solution is transparent. Here, "room temperature" may be in the range of approximately 10°C to 40°C, and is 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 an organic solvent, for example. The organic solvent will be described later.

[0070] (Method for producing polyamide-imide resin) Polyamide-imide resins can be produced by known methods and are not particularly limited. For example, a polyamide-imide resin can be produced by the reaction of a diamine component and / or a diisocyanate component with an acid component. The diamine component, diisocyanate component, and acid component are as previously described. The above 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 appropriately adjusted depending on the batch size, the reaction conditions adopted, etc.

[0071] The organic solvent (reaction solvent) used in the production of polyamide-imide resin is not particularly limited. Examples of usable organic solvents include ether-based 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. One of these organic solvents may be used alone, or two or more may be used 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. Polar solvents will be described later, but for example, nitrogen-containing solvents are preferred.

[0072] In one embodiment, the polyamide-imide resin can be produced by first producing a precursor of the polyamide-imide resin by a reaction between an acid component and a diamine component, and then obtaining the polyamide-imide resin by dehydrating and cyclizing this precursor. However, the method of cyclizing the precursor is not particularly limited, and methods well known in the art can be used. For example, a thermal cyclization method in which dehydration and cyclization are performed by heating under normal or reduced pressure, or a chemical cyclization method using a dehydrating agent such as acetic anhydride in the presence or absence of a catalyst can be used.

[0073] In the case of the thermal ring-closing method, it is preferable to remove the water produced in the dehydration 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, an organic solvent that can azeotrope with water, such as benzene, toluene, or xylene, may be used in combination to remove the water azeotropically.

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

[0075] Chemical dehydrating agents may be used in a ratio of 90 to 600 mol% of the total amount of diamine components, and substances that promote the cyclization reaction may be used in a ratio of 40 to 300 mol% of the total amount of diamine components. Dehydration catalysts such as triphenyl phosphite, tricyclohexyl phosphite, triphenyl phosphate, phosphoric acid, phosphorus compounds such as phosphorus pentoxide, and boron compounds such as boric acid and boric anhydride may also be used.

[0076] In the production of polyamide-imide resin, the ratio (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, it is preferable that the total amount of the diamine component be 0.90 to 1.10 moles per 1.00 mole of the total amount of the acid component, more preferably 0.95 to 1.05 moles, and even more preferably 0.97 to 1.03 moles.

[0077] <Polyamide-imide resin composition> In one embodiment, the polyamide-imide resin composition (hereinafter sometimes abbreviated as "resin composition") comprises the polyamide-imide resin of the above embodiment and a solvent. In this specification, the resin composition may also be referred to as varnish. (solvent) The solvent can be any solvent capable of dissolving polyamide-imide resin, and is not particularly limited. "A solvent capable of dissolving polyamide-imide resin" means a solvent in which, without any particular restrictions on the solvent temperature, when the solution obtained by adding polyamide-imide resin powder to the solvent and stirring is observed visually, no precipitate 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 during the production of the resin. In particular, the use of a polar solvent is preferred.

[0078] Examples of polar solvents include nitrogen-containing compounds such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, and 1,3-dimethyltetrahydro-2(1H)-pyrimidinone; sulfur-containing compounds such as 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; diethylene glycol dialkyl ethers such as ethylene glycol, glycerin, 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. Examples include triethylene glycol dialkyl ethers such as triethylene glycol dipropyl ether and triethylene glycol dibutyl 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 ethers containing 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 using two or more in combination, they can be mixed in any proportion.

[0080] Among the solvents mentioned above, solvents with relatively low boiling points are preferred from the viewpoint of film-forming properties. For example, diethylene glycol dimethyl ether, triethylene glycol, and triethylene glycol dimethyl ether can be preferably used.

[0081] The amount of solvent in the above resin composition can be adjusted as appropriate, taking viscosity into consideration. 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 above resin composition. More preferably, the solvent is added in a ratio of 5,000 to 2,000 parts by mass per 100 parts by mass of the total amount of resin.

[0082] (Additives) To the above polyamide-imide resin composition (varnish), additives such as colorants and coupling agents, and additional components such as resin modifiers may be added as needed. When the polyamide-imide resin composition contains additional components, it is preferable that the amount of additional components is 50 parts by mass or less per 100 parts by mass of the total amount of polyamide-imide resin (solid component) in the polyamide-imide resin composition. By limiting the amount of additional components to 50 parts by mass or less, it becomes easier to suppress a decrease in the physical properties of the resulting coating film.

[0083] In one embodiment, the polyamide-imide resin composition may contain a coupling agent. Examples of additional components that can be used are given below. (Coupling agent) The coupling agent that can be used is not particularly limited and may be silane-based, titanium-based, or aluminum-based, but silane-based coupling agents are most preferred. Examples of silane-based coupling agents 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, and γ-mercap. Topropyltrimethoxysilane, 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-dihydroimidazole-1-yl-propyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyldimethoxysilane, 3-cyanopropyltriethoxysilane, hexamethyldisilazane, N,Examples include O-bis(trimethylsilyl)acetamide, methyltrimethoxysilane, methyltriethoxysilane, ethyltrichlorosilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, amyltrichlorosilane, octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltri(methacryloyloxy)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, methylsilyltriisocyanate, vinylsilyltriisocyanate, phenylsilyltriisocyanate, tetraisocyanate silane, and ethoxysilane isocyanate. These may be used individually or in combination of two or more types.

[0084] While there are no particular restrictions on the titanium-based coupling agent, examples include isopropyltrioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl toridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tris(n-aminoethyl) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, dicumylphenyl oxyacetate titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, tetraisopropyl titanate, tetrano Examples include malbutylate 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 triethanolamine, polyhydroxytitanium stearate, tetramethyl orthotitanate, tetraethyl orthotitanate, tetrapropyl orthotitanate, tetraisobutyl orthotitanate, stearyl titanate, cresyl titanate monomer, cresyl titanate polymer, diisopropoxy-bis(2,4-pentadionate)titanium(IV), diisopropyl-bis-triethanolaminotitanate, octylene glycol titanate, tetra-n-butoxytitanium polymer, tri-n-butoxytitanium monostearate polymer, and tri-n-butoxytitanium monostearate. These may be used individually or in combination of two or more types.

[0085] While there are no particular limitations on the aluminum-based coupling agents, examples include aluminum chelates such as ethyl acetate aluminum diisopropylate, aluminum tris(ethyl acetate), alkyl acetate aluminum diisopropylate, aluminum monoacetylacetate bis(ethyl acetate), aluminum tris(acetylacetonate), aluminum monoisopropoxymonoleoxyethyl acetate, aluminum di-n-butoxide-monoethyl acetate, aluminum di-isopropoxide-monoethyl acetate, aluminum isopropylate, mono-sec-butoxyaluminum diisopropylate, aluminum sec-butyrate, and aluminum alcoholates such as aluminum ethylate. These may be used individually 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 obtained by measuring the varnish dissolved in a solvent so that the non-volatile component (solid component) is 1 to 20% by mass, using an E-type viscometer at 25°C and 10 rpm. If the viscosity measured at 10 rpm is 10 mPa·s or higher, it is easy to ensure a sufficient film thickness during application. Furthermore, if the viscosity is 400 mPa·s or lower, it is easy to ensure a uniform film thickness during application. Therefore, by adjusting the viscosity within the above range, it is easy to obtain excellent printability.

[0087] In one embodiment, from the viewpoint of obtaining excellent coating properties, the viscosity is preferably greater than 50 mPa·s, and more preferably greater than 100 mPa·s. If the viscosity is too low, it may be difficult to handle due to wetting beyond a predetermined range. The viscosity mentioned above can be measured using, for example, a viscometer (RE type) manufactured by Toki Sangyo Co., Ltd. For measurement, the measurement temperature is set to 25°C ± 0.5°C, 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 measurement.

[0088] In one embodiment, the film thickness when the resin composition is formed 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 this 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 coating 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 above film can be carried out, for example, by heating at 50°C for 10 minutes and then drying at 260°C for 1 hour. The above elastic modulus is a value measured using a dynamic viscoelasticity measuring device. From the viewpoint of further improving the reliability in power semiconductor devices, it is preferable that the above film has appropriate flexibility. Therefore, in one embodiment, the elastic modulus of the above film is more preferably in the range of 3.0 GPa to 4.5 GPa.

[0090] The modulus of elasticity can be measured, for example, using the "Rheogel-E4000" dynamic viscoelasticity measuring device manufactured by UBM Co., Ltd. The above modulus of elasticity is a value obtained by using a film obtained by coating 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 is suitable for use as a component material for semiconductor devices because it has excellent heat resistance and flexibility. For example, an insulating layer, adhesive layer, protective layer, etc., can be formed in a semiconductor device using the above resin composition, and a semiconductor device having these layers will have excellent adhesion between components and excellent reliability. In one embodiment, the resin composition can be suitably used to form a primer layer provided between a encapsulant and a substrate, or between a encapsulant and a semiconductor element, in a semiconductor device. The adhesion between each component can be evaluated by shear strength.

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

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

[0094] Shear strength can be measured using, for example, a shear strength measuring device (Nordson Advanced Technologies, Ltd. 4000 series). For measurement, a sample can be used in which a resin composition is applied and dried on a Ni substrate to form a film, and a φ5 mm resin encapsulation layer is molded on top of it using an epoxy encapsulating resin. Typical measurement conditions may be a heat stage temperature of 260°C and a probe speed of 3 mm / min. The substrate material and the encapsulating material constituting the resin encapsulation layer can be changed as appropriate. For the measurement, a Cu substrate may be used instead of a Ni substrate, or a Cu substrate with Ag plating may be used.

[0095] As described above, when the above resin composition is used in a semiconductor device to form a primer layer provided between the encapsulant and the substrate, or between the encapsulant and the semiconductor element, it is preferable that the difference in the coefficient of linear expansion (CTE) between each component and the film made of the above resin composition is small, from the viewpoint of suppressing the generation of stress due to thermal expansion and contraction and improving adhesion. From this viewpoint, 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, it is preferable that the CTE of the resin composition containing the polyamide-imide resin is also within the above range.

[0096] The above CTE is a value measured using a film obtained by applying and drying a varnish of a resin or resin composition. The measurement can be performed using, for example, a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation "SS7100"). The 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 as defined herein 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 dried film made using the resin composition of the above embodiment. The components of a semiconductor device generally include semiconductor elements mounted on a substrate and a sealing member (sealing layer). Semiconductor elements are 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 a resin. Hereinafter, a sealing layer made of resin will be referred to as a resin sealing layer.

[0098] In the semiconductor device described above, the adhesion between components can be easily improved by forming a dried film using the resin composition of the above embodiment as a primer layer between each component. More specifically, for example, by forming a dried film of the resin composition between the resin encapsulation layer and the substrate, or between the resin encapsulation layer and the semiconductor element, the adhesion between components can be ensured, and delamination during cycle testing can be prevented. From this viewpoint, in one embodiment, the semiconductor device comprises 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, wherein the primer layer is preferably composed of a dried film formed using the semiconductor device resin composition of the above embodiment. The substrate may be a lead frame composed of a die pad on which the semiconductor element is mounted 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 for a power semiconductor device using the silicon carbide (SiC) substrate or gallium nitride (GaN) substrate. When a power semiconductor device is constructed using the resin composition, the decrease in adhesion between components during heat cycle testing can be easily suppressed.

[0100] The following will provide a detailed explanation of a typical structure of the semiconductor device according to the above embodiment, with reference to the figures. Figure 1 is a schematic cross-sectional view showing one embodiment of a semiconductor device. The semiconductor device shown in Figure 1 comprises a die pad 1a, a semiconductor element 2, a primer layer 3, a lead 1b, a wire 4, and a resin encapsulation layer 5, the primer layer 3 being formed from the resin composition of the above embodiment. As shown in Figure 1, by providing the primer layer 3 formed from the above resin composition on the semiconductor element mounting surface of the substrate 1 that is in contact with the resin encapsulation layer 5 (the surface of the die pad 1a on which the lead 1b and semiconductor element 2 are mounted), the adhesion between each component can be easily improved.

[0101] In one embodiment, the 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 on which a semiconductor element is mounted 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 polyamide-imide resin as the resin component. The primer layer can be obtained by applying the resin composition to a predetermined location and drying the coating film.

[0103] The material of the lead frame, which consists 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 power semiconductor devices, the die pad material is preferably at least one selected from the group consisting of Ni and Cu. Furthermore, 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 device is not particularly limited and may be, for example, a silicon wafer, a silicon carbide wafer, etc.

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

[0105] The method for applying the above-mentioned resin layer (primer layer) is not particularly limited, but spin coating, spray coating, or dispense coating is preferred. The drying method for the above-mentioned resin layer can be carried out by a method known in the art. The resin composition of the above embodiment also has excellent properties such as sputter resistance, plating resistance, and alkali resistance required in the process of forming rewiring. For this reason, the resin composition of the above embodiment can be suitably used as a material for any semiconductor device, not limited to the configuration of the semiconductor device described above. [Examples]

[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 resins (Synthesis Example 1) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 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 were added under a nitrogen stream. Then, 284 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) was added and dissolved to obtain the solution. Next, 21.1 g of trimellitic anhydride chloride (hereinafter referred to as 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 triethylamine (hereinafter referred to as TEA) was added and the mixture was reacted at room temperature for at least 12 hours to obtain a polyamic acid solution. The obtained polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamide-imide resin solution. This polyamide-imide resin solution was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-1). The obtained polyamide-imide 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 polyamide-imide resin (PAI-1) was measured using gel permeation chromatography (hereinafter referred to as GPC) on a standard polystyrene basis, and the Mw was found to be between 57,000 and 68,000.

[0108] The measurement conditions for GPC are as follows: Liquid transfer pump: Shimadzu Corporation LC-20AD UV-Vis detector: Shimadzu Corporation SPD-20A, UV270nm 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: 5 mg / 1 mL Flow rate: 1 mL / min Column temperature: 40°C Molecular weight standard material: Standard polystyrene

[0109] (Synthesis Example 2) In the preparation of the polyamide-imide resin (PAI-1) described in Synthesis Example 1, powdered polyamide-imide resin (PAI-2) was obtained by following the same method as in Synthesis Example 1, except that 15.7 g of 9,9-bis(4-aminophenyl)fluorene and 8.9 g of 4,4'-diaminodiphenylmethane were used. The polyamide-imide resin powder (PAI-2) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight-average molecular weight (Mw) of the obtained polyamide-imide resin (PAI-2) was measured on a standard polystyrene basis and found to be 72,000. The Mw measurement was performed in the same manner as described in Synthesis Example 1.

[0110] (Synthesis Example 3) In the preparation of the polyamide-imide resin (PAI-1) described in Synthesis Example 1, powdered polyamide-imide resin (PAI-3) was obtained by following the same method as in Synthesis Example 1, except that 6.3 g of 9,9-bis(4-aminophenyl)fluorene and 14.3 g of 4,4'-diaminodiphenylmethane were used. The polyamide-imide resin powder (PAI-3) was soluble in a polar solvent (NMP) at room temperature (25°C). The weight-average molecular weight (Mw) of the obtained polyamide-imide resin (PAI-3) was measured on a standard polystyrene basis and found to be 100,000. The Mw measurement was performed in the same manner as described in Synthesis Example 1.

[0111] (Synthesis Example 4) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 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 were added under a nitrogen stream, and then 250 g of NMP was added and dissolved to obtain the 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 the mixture was reacted at room temperature for at least 12 hours to produce a polyamic acid solution. The obtained polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamide-imide resin solution. This polyamide-imide resin solution was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-5). The polyamide-imide 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 polyamide-imide resin (PAI-5) was measured using GPC on a standard polystyrene basis, and the Mw was found to be 65,000. The Mw was measured in the same manner as described in Synthesis Example 1.

[0112] (Synthesis Example 5) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 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 were added under a nitrogen stream, and then 238 g of NMP was added and dissolved to obtain the 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 the mixture was reacted at room temperature for at least 12 hours to produce a polyamic acid solution. The obtained polyamic acid solution was further subjected to dehydration condensation at 180°C for 8 hours to obtain a polyamide-imide resin solution. This polyamide-imide resin solution was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-5). The polyamide-imide 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 polyamide-imide resin (PAI-5) was measured using GPC on a standard polystyrene basis, and the Mw was found to be 42,000. The Mw was measured in the same manner as described in Synthesis Example 1.

[0113] (Synthesis Example 6) In a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser with oil-water separator, 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 added under a nitrogen stream, and then 700 g of NMP was added to dissolve the compounds and 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 reacted at room temperature for 3 hours to produce a polyamic acid solution. The obtained polyamic acid solution was further subjected to dehydration condensation at 190°C for 6 hours to produce a polyamide-imide resin solution. The polyamide-imide resin varnish was poured into water, and the resulting precipitate was separated, pulverized, and dried to obtain powdered polyamide-imide resin (PAI-6). The weight-average molecular weight (Mw) of the obtained polyamide-imide resin (PAI-6) was measured using gel permeation chromatography (GPC) on a standard polystyrene basis, and the Mw was found to be 75,000. The measurement of Mw was carried out in the same manner as described in Synthesis Example 1.

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

[0115] (Example 1) In a 0.5-liter four-necked flask, under a nitrogen stream, 12 g of polyamide-imide 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 silane coupling agent (product name KBM-402 (3-glycidoxypropylmethyldimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.) were added and stirred for 12 hours to obtain a yellow reaction mixture. The obtained yellow reaction mixture was packed into a filter KST-47 (manufactured by Advantec Co., Ltd.) and subjected to pressure filtration at a pressure of 0.3 MPa to obtain a primer varnish (P-1) for semiconductor devices.

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

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

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

[0119] (Example 5) A primer varnish (P-5) for semiconductor devices was prepared in the same manner as in Example 1, except that the polyamide-imide 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 (P-6) for semiconductor devices was prepared in the same manner as in Example 1, except that the polyamide-imide resin powder (PAI-1) used in Example 1 was replaced with (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) The various characteristics were evaluated according to the following criteria. (modulus of elasticity) The semiconductor device primer varnishes (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were coated onto a substrate using a bar coater and then heat-dried to obtain a dried film with a thickness of 10 μm. The heat drying to form the above dried film was carried out under 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 sample for measurement, and the following measurements were performed. The elastic modulus of polyamide-imide resin was measured using a dynamic viscoelasticity measuring device (Rheogel-E4000) manufactured by UBM Corporation. The measurement was performed with a chuck distance of 20 mm, a temperature of 35°C, and a measurement frequency of 10 MHz. The measured values ​​are shown in Table 1.

[0122] (Glass transition temperature) The semiconductor device primer varnishes (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were coated onto a substrate using a bar coater and then heat-dried to obtain a dried film with a thickness of 10 μm. The heat drying to form the above dried film was carried out under 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 sample for measurement, and the following measurements were performed. The measurements were performed 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 of the linear expansion coefficient obtained from the TMA measurement, from α1 to α2, was defined as the glass transition temperature.

[0123] (Coefficient of linear expansion) The semiconductor device primer varnishes (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were coated onto a substrate using a bar coater and then heat-dried to obtain a dried film with a thickness of 10 μm. To form the above dried film, heating was performed 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 sample for measurement, and the coefficient of linear thermal expansion (CTE) was measured. The measurement was performed using a thermomechanical analyzer (TMA, Hitachi High-Tech Science Corporation "SS7100") under 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 of the line was defined as the CTE value.

[0124] (Adhesion (Shear Strength)) The adhesion properties of the semiconductor device primer varnishes (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1 were evaluated using a 4000 series shear strength measuring device manufactured by Arctec Co., Ltd. Specifically, first, the primer varnish was applied to a Ni substrate using a spray coating device (model number: SV91) manufactured by San-ei Tech Co., Ltd., and a dried film was obtained by heating and drying. The thickness of the dried film was 10 μm. Next, a φ5 mm resin encapsulation layer was molded onto the above-mentioned dried film to obtain a sample for measurement. Showa Denko Materials Co., Ltd.'s epoxy encapsulation resin (CEL-420HFC) was used as the encapsulant. The obtained sample was placed on the heat stage of a 4000 series shear strength measuring device manufactured by Arctech Co., Ltd., and the shear strength was measured. The measurement was performed at a temperature of 260°C with 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 shear strength measurement results at 260°C, according to the following criteria. The evaluation results are shown in Table 1. <Standards for adhesion in high-temperature environments> A: The shear strength at 260℃ is 18.0 MPa or higher. B: The shear strength at 260℃ is 11 MPa or higher and less than 18.0 MPa. C: The shear strength at 260℃ is less than 11 MPa.

[0126] (Reliability evaluation (moisture absorption reflow test)) Moisture absorption reflow tests were performed on the semiconductor device primer varnishes (P-1) to (P-6) obtained in Examples 1 to 5 and Comparative Example 1. Specifically, first, a package was assembled with a Cu lead frame and Si chips mounted on it. Then, the primer varnish was applied and dried using a spray coating device (model number: SV91) manufactured by San-ei Tech Co., Ltd. to obtain a dried film. The drying conditions were a temperature of 260°C and a drying time of 1 hour. Next, a resin encapsulation layer was molded on the above-mentioned dried film using "CEL-8240," a product manufactured by Showa Denko Materials Co., Ltd., as the encapsulating material, to obtain an evaluation sample. Next, using the obtained evaluation samples, a moisture absorption reflow test was performed 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, a high-precision ultrasonic microscope (C-SAM) was used to observe whether delamination had occurred between the resin encapsulation layer, the dried resin film (primer layer), and the lead frame in the semiconductor devices before and after the reliability test (moisture-absorbing reflow test). The results are shown in Table 1. The reliability test results shown in Table 1 are presented as the number of samples in which delamination 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℃±5℃), using pure water.

[0128] The results of the characteristic evaluations in Examples 1-5 and Comparative Example 1 are summarized in Table 1. [Table 1]

[0129] In Table 1, the 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 1-5) 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 1-5, and the adhesion test under high temperature conditions of 260°C yielded significantly inferior results. The resin composition of Comparative Example 1 uses a polyamide-imide resin that does not have a cardo-structured fluorene skeleton. Furthermore, the results of the reliability tests using the moisture-absorbing reflow test in Examples 1 to 3 show that the Tg can be easily increased by adjusting the ratio of structural unit (Ia) to structural unit (IIa). Moreover, as seen in Examples 1, 4, and 5, when the Tg exceeds 300°C, it is easy to improve reliability by obtaining good results in the moisture-absorbing reflow test as well as excellent adhesion under high-temperature conditions. From the above, it can be seen that, according to the present invention, by having a polyamide-imide resin that has a combination of structural units having a cardioid fluorene skeleton and specific structural units, it is possible to provide a resin and 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 Diaper 1b Lead 2 Semiconductor elements 3. Primer layer (film of resin composition) 4 wires 5. Resin encapsulation layer

Claims

1. A polyamide-imide resin obtained using a diamine component and / or a diisocyanate component and an acid component, The polyamide-imide resin comprises, in relation to the total amount of structural units derived from the diamine component and / or diisocyanate component, 10 to 85 mol% of structural unit (Ia) represented by the following formula, at least one selected from the group consisting of structural units (IIb) and (IIc) represented by the following formulas in amounts of 10 to 80 mol%, 5 to 15 mol% of structural unit (IIIa) represented by the following formula, and structural units derived from the diamine component and / or diisocyanate component in amounts of 20 mol% or less that are different from structural units (Ia), (IIb), (IIc), and (IIIa), and further comprises structural unit (IVa) represented by the following formula. 【Chemistry 1】 [In formula (Ia), X independently represents a hydrogen atom or a substituent selected from the group consisting of a halogen atom, a C1-C9 alkyl group, a C1-C9 alkoxy group, and a hydroxyalkyl group.] 【Chemistry 2】 [In formulas (IIb) and (IIc), S independently represents an alkyl group having 1 to 3 carbon atoms, b represents an integer from 0 to 3, and c represents an integer from 0 to 4.] 【Transformation 3】 [In formula (IIIa), R independently represents a hydrogen atom or a substituent selected from the group consisting of C1-C9 alkyl groups, C1-C9 alkoxy groups, and halogen atoms, and n represents an integer from 1 to 6.] 【Chemistry 4】

2. The polyamide-imide resin according to claim 1, wherein the polyamide-imide resin is composed of structural unit (Ia), structural unit (IIb) or (IIc), structural unit (IIIa), and structural unit (IVa).

3. The polyamide-imide resin according to claim 1 or 2, wherein the coefficient of linear thermal expansion is 40 to 70 ppm / °C.

4. The polyamide-imide resin according to claim 1, wherein the weight-average molecular weight is 30,000 to 120,000.

5. A polyamide-imide resin according to any one of claims 1 to 4, wherein the glass transition temperature is 250°C or higher.

6. A polyamide-imide resin according to any one of claims 1 to 5, wherein the glass transition temperature is 300°C or higher.

7. A polyamide-imide resin composition comprising the polyamide-imide resin according to any one of claims 1 to 6 and a solvent.

8. A semiconductor device comprising a substrate and a film formed using the polyamide-imide resin composition described in claim 7.

9. Furthermore, the semiconductor device according to claim 8, further comprising a resin sealing layer.

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