Method for producing polyimide cured film

Abstract

To provide a method for producing a polyimide film which exhibits a low dielectric loss tangent, is reduced in frequency dependency of the dielectric loss tangent, and has a high heat weight reduction temperature.SOLUTION: A method for producing a polyimide cured film includes: (1) a step of coating a photosensitive resin composition containing a polyimide precursor onto a substrate, and forming a photosensitive resin layer onto the substrate; (2) a step of drying and heating the obtained photosensitive resin layer; (3) a step of exposing the obtained photosensitive resin layer; (4) a step of developing the obtained photosensitive resin layer; and (5) a step of heating the photosensitive resin layer remaining on the substrate at 150-250°C, and forming a cured film, in which the step (2) and / or (5) is performed under a pressure of 50 torr or more and 580 torr or less, and in polyimide of the obtained polyimide cured film, an imide group concentration that is a ratio of the imide group to a molecular weight of a repeating unit including a structure derived from a tetracarboxylic acid and diamine is 12-30 wt.%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a polyimide cured film.

Background Art

[0002] Conventionally, polyimide resins having excellent heat resistance, electrical properties, and mechanical properties have been used for insulating materials of electronic components and passivation films, surface protection films, interlayer insulating films, etc. of semiconductor devices. Among these polyimide resins, those provided in the form of a photosensitive polyimide precursor composition can easily form a heat-resistant relief pattern film by coating, exposing, developing, and heat imidization treatment by curing of the composition. Such a photosensitive polyimide precursor composition has a feature that it enables a significant reduction in the number of steps compared to conventional non-photosensitive polyimide materials.

[0003] By the way, semiconductor devices (hereinafter also referred to as "devices") are mounted on printed circuit boards by various methods according to the purpose. Conventional devices have generally been manufactured by a wire bonding method in which a thin wire is connected from an external terminal (pad) of the device to a lead frame, but recently, from the viewpoints of high-speed transmission and thinning of the package height, a semiconductor chip mounting technology called fan-out wafer level package (FOWLP) has been proposed. FOWLP is a mounting technology in which a pre-processed wafer is diced to produce individual chips, the individual chips are reconstructed on a support and sealed with a molding resin, and a redistribution layer is formed after the support is peeled off.

[0004] In recent years, it has been urgent to develop packages for the fifth-generation mobile communication system (5G), a new communication standard. Different from the conventional 4G technology, 5G uses the frequency band of millimeter waves (10 GHz to 80 GHz), enabling high-speed large-capacity communication, low signal latency, and simultaneous connection of multiple terminals, which were not achievable in conventional communication. In the millimeter-wave band, the influence of transmission loss is significant in the signal wiring of printed circuit boards, raising concerns about heat generation and transmission delay. Therefore, to reduce transmission loss, a front-end module (FEM) for radio wave transmission and reception and an antenna are integrated to develop an antenna-in-package (AiP) (see, for example, Patent Document 1 below). In AiP, since the wiring length is short, it is possible to suppress the transmission loss that increases in proportion to the wiring length.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, there are also limitations in suppressing transmission loss in package design, and improvements in the material aspect are also expected. When the dielectric constant and dielectric tangent (tanδ) of the insulating material used for wiring formation are high, dielectric loss increases and transmission loss increases. In particular, although polyimide has excellent insulation performance and film physical properties, since the imide group itself is a polar functional group, the values of the dielectric constant and dielectric tangent are high, and improvement in dielectric characteristics is required.

[0007] In view of the above technical level, the problems to be solved by the present invention are to provide a method for manufacturing a polyimide cured film, a method for manufacturing a cured relief pattern, which exhibit a low dielectric tangent, have little frequency dependence of the dielectric tangent, and have a high thermogravimetric reduction temperature, and a polyimide cured film obtained by the method.

[0008] The inventor unexpectedly found that the above problems can be solved by controlling the pressure during heating within a predetermined range in the method for producing a polyimide cured film using a photosensitive resin composition containing a polyimide precursor as a raw material, and thus completed the present invention.

[0009] That is, the present invention is as follows. [1] The following steps: (1) A step of applying a photosensitive resin composition containing a polyimide precursor onto a substrate to form a photosensitive resin layer on the substrate; (2) A step of drying and heating the obtained photosensitive resin layer; (3) A step of exposing the obtained photosensitive resin layer; (4) A step of developing the obtained photosensitive resin layer; and (5) A step of heat-treating the photosensitive resin layer remaining on the substrate at 150°C to 250°C to form a cured film, which is a method for producing a polyimide cured film, wherein the step (2) and / or (5) is carried out under a pressure of 50 torr or more and 580 torr or less, and in the polyimide of the obtained polyimide cured film, the imide group concentration, which is the ratio occupied by the imide group with respect to the molecular weight of the repeating unit containing the structure derived from tetracarboxylic acid and diamine, is 12 wt% to 30 wt%. [2] The method for producing a polyimide cured film according to [1] above, wherein the dielectric loss tangent at a frequency of 10 GHz by the perturbation method split cylinder resonator method of the cured film obtained by step (5) is 0.001 to 0.007. [3] The method for producing a polyimide cured film according to [1] or [2] above, wherein the step (5) is carried out under a pressure of 50 torr or more and 580 torr or less. [4] The method for producing a polyimide cured film according to [3] above, wherein in the step (5), when the set heat curing temperature is reached, the temperature change from the set temperature is 30.0°C or less. [5] The method for producing a polyimide cured film according to any one of [3] to [5], wherein in the region where the temperature change in the step (5) is 9.5 ° C / min or less, the change in pressure is within 150 torr. [6] The method for producing a polyimide cured film according to any one of [1] to [5], wherein the weight loss rate when the obtained polyimide cured film is heated to 320 ° C is 0.01% to 0.5%. [7] The method for producing a polyimide cured film according to any one of [1] to [6], wherein the weight loss rate when the obtained polyimide cured film is heated to 350 ° C is 0.1% to 1.5%. [8] The obtained polyimide cured film satisfies the following mathematical formula (i): 0.001 <(tanδ40 - tanδ10) / tanδ10 <0.2 (i) {In the formula, tanδ40 is the dielectric loss tangent at a frequency of 40 GHz by the perturbation method split cylinder resonator method, and tanδ10 is the dielectric loss tangent at a frequency of 10 GHz by the perturbation method split cylinder resonator method.}. The method for producing a polyimide cured film according to any one of [1] to [7]. [9] The dielectric loss tangent measured at a frequency of 10 GHz by the perturbation method split cylinder resonator method is 0.001 to 0.009, and the following general formula (10):

Chemical formula

[10] The polyimide contains at least one of the structures represented by the following formula:

Chemical formula

[11] The polyimide cured film for forming an interlayer insulating film for rewiring according to [9] or

[10] above, having a weight loss rate of 0.01% to 0.5% when heated to 320 °C and a weight loss rate of 0.1% to 1.5% when heated to 350 °C.

[12] The polyimide cured film for forming an interlayer insulating film for rewiring, having a weight loss rate of 0.01% to 0.5% when heated to 320 °C, a weight loss rate of 0.1% to 1.5% when heated to 350 °C, and a dielectric tangent of 0.0021 to 0.0085 when measured at a frequency of 40 GHz by the perturbation method split cylinder resonator method.

[13] The polyimide precursor is represented by the following general formula (1):

Chemical formula

Chemical formula

[14] The manufacturing method of the polyimide cured film according to any one of [1] to [8] and

[13] above, wherein the photosensitive resin composition contains a photoinitiator.

[15] In the general formula (1), X 1 is the following formula:

Chemical formula

[14] , which is at least one of the structures represented by

[16] In the general formula (1), X 1 is the following formula: [Chemical formula] {In the formula, * represents a connecting part.} The method for producing a polyimide cured film according to any one of the above

[13] to

[15] , which is at least one of the structures represented by [Advantages of the Invention]

[0010] The method for producing a polyimide cured film according to the present invention can provide a polyimide cured film having low frequency dependence of dielectric loss tangent and suppressed thermal weight loss at a temperature equal to or higher than the heat curing temperature by performing heating under reduced pressure. [Modes for Carrying Out the Invention]

[0011] Hereinafter, modes for carrying out the present invention (hereinafter abbreviated as "embodiments") will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist. Throughout this specification, in the general formula, when there are a plurality of structures represented by the same reference numeral in the molecule, they are independently selected unless otherwise specified, and they may be the same or different from each other. Also, the structures represented by the common reference numerals in different general formulas are also independently selected unless otherwise specified, and they may be the same or different from each other.

[0012] [Method for Producing Cured Film] One embodiment of the present invention includes the following steps: (1) A step of applying a photosensitive resin composition containing a polyimide precursor onto a substrate to form a photosensitive resin layer on the substrate; (2) A step of drying and heating the obtained photosensitive resin layer; (3) A step of exposing the obtained photosensitive resin layer; (4) A step of developing the obtained photosensitive resin layer; and (5) A step of heat-treating the photosensitive resin layer remaining on the substrate at 150°C to 250°C to form a cured film, which is a method for producing a polyimide cured film. In the above steps (2) and / or (5), the steps are carried out under a pressure of 50 torr or more and 580 torr or less. In the polyimide of the obtained polyimide cured film, the imide group concentration, which is the ratio occupied by the imide group with respect to the molecular weight of the repeating unit containing the structure derived from tetracarboxylic acid and diamine, is 12 wt% to 30 wt%. From the perspective of dielectric loss tangent, it is preferable that step (5) is carried out under a pressure of 50 torr or more and 580 torr or less. Such a pressure is preferably 80 torr to 580 torr, more preferably 100 torr to 500 torr, still more preferably 120 torr to 450 torr, and even more preferably 160 torr to 420 torr. Without being bound by a specific theory, when heating under a pressure of 580 torr or less, the boiling point of the low molecular weight compounds present in the film decreases, making them easier to vaporize. By being removed from the film, a cured film with low dielectric loss in the high frequency region can be obtained. At the same time, since there are fewer components that volatilize when the cured film is heated, the weight loss rate during heating decreases. Also, without being bound by theory, heating under a pressure of 50 torr or more prevents the solvent molecules from vaporizing immediately under reduced pressure and does not inhibit the progress of imidization by heat curing.

[0013] Hereinafter, each step will be described. [(1) A step of applying a photosensitive resin composition containing a polyimide precursor onto a substrate to form a photosensitive resin layer on the substrate] In step (1), a photosensitive resin composition containing a polyimide precursor is applied onto a substrate, and if necessary, it is then dried to form a photosensitive resin layer. As the coating method, methods conventionally used for coating a photosensitive resin composition can be employed, for example, methods of coating with a spin coater, a bar coater, a blade coater, a curtain coater, a screen printing machine, etc., or a method of spray coating with a spray coater can be used.

[0014] [(2) Step of drying and heating the obtained photosensitive resin layer] In step (2), if necessary, a coating film made of the photosensitive resin composition can be dried. As the drying method, for example, methods such as air drying, heat drying by an oven or a hot plate, and vacuum drying are used. Specifically, when performing air drying or heat drying, the temperature can be carried out at 20°C to 140°C, more preferably 80°C to 140°C, and even more preferably 80°C to 120°C. The drying time can be carried out for 1 minute to 1 hour, more preferably 2 minutes to 30 minutes, and even more preferably 2 minutes to 10 minutes. By drying under the above conditions, a photosensitive resin layer can be formed on the substrate as described above. When performing the (2) drying and heating step by vacuum drying, the heat source is preferably selected from a hot plate or an infrared lamp. Further, from the viewpoint of heating efficiency under reduced pressure, it is preferable to heat with the wafer on which the coating film is formed placed on the heat source. The (2) drying and heating step can be carried out under a pressure of 50 torr or more and 580 torr or less. The change in pressure from the set value is preferably within 150 torr, more preferably within 100 torr, even more preferably within 80 torr, and even more preferably within 60 torr.

[0015] [(3) Step of exposing the obtained photosensitive resin layer] In step (3), the photosensitive resin layer formed in the above step (1) is exposed using an exposure apparatus such as a contact aligner, a mirror projection, a stepper, etc., through a photomask or reticle having a pattern or directly by an ultraviolet light source or the like. Thereafter, for the purpose of improving photosensitivity and the like, post-exposure baking (PEB) and / or pre-development baking may be performed as needed, with any combination of temperature and time. The range of baking conditions is preferably such that the temperature is 40°C to 120°C and the time is 10 seconds to 240 seconds. However, it is not limited to this range as long as it does not inhibit the various properties of the negative photosensitive resin composition.

[0016] [(4) Step of developing the obtained photosensitive resin layer] In step (4), when the photosensitive resin composition is negative, the unexposed portion of the photosensitive resin layer after exposure is developed and removed. As a developing method for developing the photosensitive resin layer after exposure (irradiation), any method can be selected and used from conventionally known photoresist developing methods, such as the spin spray method, the paddle method, the dipping method with ultrasonic treatment, etc. Further, after development, a post-development bake may be performed as needed with any combination of temperature and time for the purpose of adjusting the shape of the relief pattern. As the developer used for development, for example, a good solvent for the negative photosensitive resin composition or a combination of the good solvent and a poor solvent is preferable. Examples of the good solvent include N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N,N-dimethylacetamide, cyclopentanone, cyclohexanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, etc. Examples of the poor solvent include toluene, xylene, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol methyl ether acetate, and water. When the good solvent and the poor solvent are mixed and used, it is preferable to adjust the ratio of the poor solvent to the good solvent according to the solubility of the polymer in the negative photosensitive resin composition. Also, two or more kinds of each solvent, for example, several kinds can be combined and used.

[0017] [(5) Step of forming a cured film by heat-treating the photosensitive resin layer remaining on the substrate at 150°C to 250°C] In step (5) (heating and curing step), the photosensitive resin layer (relief pattern) remaining on the plate obtained by the above development is heated to diffuse the photosensitive component, and (A) the polyimide precursor is imidized to convert it into a cured film made of polyimide. As the method of heat curing, for example, various methods such as those using a hot plate, those using an oven, and those using a temperature-programmable oven with a temperature increase function can be selected, but preferably a temperature-programmable oven is used. The heating pressure in the temperature-programmable oven can be carried out under normal pressure (760 torr), reduced pressure, or increased pressure, but preferably under reduced pressure (760 torr or less).

[0018] The heat curing step preferably includes a temperature increase step, a constant temperature step, and a temperature decrease step. The constant temperature step may be carried out at one temperature or at two or more different temperatures. In the temperature increase step, it is preferable that the temperature changes by 10 to 30 °C per minute. The heating temperature in the constant temperature step can be carried out at 150 °C to 250 °C, preferably at 170 to 250 °C, and more preferably at 170 to 230 °C from the viewpoint of the residual film rate before and after heating. The temperature inside the furnace in the constant temperature step preferably changes by 30.0 °C or less from the set value, more preferably 20.0 °C or less, and preferably 15.0 °C or less from the viewpoint of heating efficiency. In the constant temperature step, when the pressure is kept constant, the change in pressure from the set value is preferably within 150 torr, more preferably within 100 torr, still more preferably within 80 torr, and even more preferably within 60 torr. By keeping the pressure constant, the temperature inside the furnace in the constant temperature step becomes stable. The pressure adjustment step can be carried out in any step, but preferably before the temperature increase step from the viewpoint of temperature uniformity. When adjusting the pressure, the inside of the chamber may be replaced with nitrogen, and it is preferable to repeat the reduced pressure and nitrogen replacement two or more times. The oxygen concentration inside the chamber is preferably 10 ppm or less. In the temperature decrease step, it is preferable that the temperature changes by 10 to 50 °C per minute. The heating in the heat curing step can be carried out under the conditions of 30 minutes to 5 hours, more preferably 1 hour to 3 hours, and even more preferably 90 minutes to 3 hours. As the atmosphere gas during heat curing, air may be used, or an inert gas such as nitrogen or argon can also be used.

[0019] [Hardened film] The obtained polyimide hardened film satisfies a predetermined dielectric tangent and has a ratio of peaks near 1380 cm -1 and near 1500 cm -1 in the IR spectrum that preferably satisfies a predetermined value. From the viewpoint that the photosensitive resin composition used as a raw material in the method for producing the polyimide hardened film of the present embodiment satisfies the following mathematical formula (i) and / or (ii), it preferably contains 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent. More preferably, it contains a photo radical polymerization initiator as the photosensitizer, and even more preferably, the photosensitive resin composition is a negative type.

[0020] [Dielectric tangent]< The obtained polyimide hardened film preferably has a dielectric tangent of 0.001 to 0.009, more preferably 0.001 to 0.007, and even more preferably 0.003 to 0.0065 when measured at 10 GHz by the perturbation method split cylinder resonator method. The dielectric tangent when measured at 28 GHz is preferably 0.0021 to 0.008, more preferably 0.0030 to 0.0075, and even more preferably 0.0035 to 0.0075. The dielectric tangent when measured at 40 GHz is preferably 0.0021 to 0.0085, more preferably 0.0030 to 0.0075, and even more preferably 0.0035 to 0.0075. The dielectric tangent when measured at 60 GHz is preferably 0.0021 to 0.009, more preferably 0.0030 to 0.0085, and even more preferably 0.0035 to 0.0082. By setting it within this range, signal delay and the like tend to decrease when used as a package such as an AiP.

[0021] The obtained polyimide hardened film has the following mathematical formula (i): 0.001 < (tanδ 40-tanδ 10 ) / tanδ 10 <0.2 (i) {wherein, tanδ 40 is the dielectric tangent at a frequency of 40 GHz by the perturbation method split cylinder resonator method, and tanδ 10 is the dielectric tangent at a frequency of 10 GHz by the perturbation method split cylinder resonator method.}, and / or the following mathematical formula (ii): 0.001 < (tanδ 60 -tanδ 10 ) / tanδ 10 <0.29 (ii) {wherein, tanδ 60 is the dielectric tangent at a frequency of 60 GHz by the perturbation method split cylinder resonator method, and tanδ 10 is the dielectric tangent at a frequency of 10 GHz by the perturbation method split cylinder resonator method.} is preferably satisfied. When the above mathematical formula (i) and / or (ii) is satisfied, by reducing the polarity of the cured film, the dielectric tangent can be reduced, and since the compatibility between the resins is good, the resin composition before curing can be stored without phase separation, and the resolution at the time of relief pattern formation tends to be maintained.

[0022] <IR spectrum> The obtained polyimide cured film preferably satisfies a ratio of a peak around 1380 cm -1 to a peak around 1500 cm -1 in the IR spectrum of 0.30 to 0.54, more preferably 0.35 to 0.54, still more preferably 0.40 to 0.54, and even more preferably 0.45 to 0.54. By making the peak ratio of 1380 cm -1 to 1500 cm -1 in the IR spectrum 0.54 or less, it is possible to reduce the polarity of the entire film and suppress an increase in the dielectric tangent. On the other hand, making the peak ratio 0.30 or more is effective for maintaining the toughness of the resin, the adhesion to the metal, and the thermal properties. Furthermore, the IR spectrum can be measured by an ATR-FTIR measuring apparatus shown in the examples described later.

[0023] <Weight loss rate> From the viewpoint of the frequency dependence of the dielectric loss tangent, the obtained polyimide cured film preferably has a weight loss rate of 0.01% to 0.5% when heated to 320 ° C, more preferably 0.05% to 0.4%, and also preferably has a weight loss rate of 0.1% to 1.5% when heated to 350 ° C, more preferably 0.2% to 1.2%.

[0024] [Photosensitive resin composition] The photosensitive resin composition containing the polyimide precursor contains (A) a polyimide precursor, (B) a photosensitizer, and (D) a solvent, and optionally, the photosensitive resin composition contains other components. Each component will be described in order below.

[0025] The photosensitive resin composition may be either negative type or positive type depending on the desired application, and is preferably negative type from the viewpoint of the physical properties of the (A) polyimide precursor described later. (A) Polyimide precursor (A) The polyimide precursor is a resin component contained in the photosensitive resin composition, and preferably has the following general formula (1): [Chemical formula] {In the formula, X 1 is a tetravalent organic group having 6 to 40 carbon atoms, Y 1 is a divalent organic group having 6 to 40 carbon atoms, n 1 is an integer of 2 to 150, and R 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. However, at least one of R 1 and R 2 has the following general formula (2): [Chemical formula] (In the formula, R 3 , R 4and R 5 is each independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and m 1 is an integer of 2 to 10. It is a polyamide having a structural unit represented by.).

[0026] (A) The ratio of the monovalent organic group represented by the general formula (2) to all of R 1 and R 2 in the precursor represented by the general formula (1) contained in the polyimide precursor is preferably 50 mol% to 100 mol% from the viewpoint of high resolution, and more preferably 75 mol% to 100 mol% from the viewpoints of high chemical resistance and sensitivity.

[0027] From the viewpoints of the photosensitive characteristics and mechanical characteristics of the photosensitive resin composition, n1 in the general formula (1) is preferably an integer of 3 to 100, and more preferably an integer of 5 to 70.

[0028] In the general formula (1), the tetravalent organic group represented by X 1 is preferably an organic group having 6 to 40 carbon atoms in terms of achieving both heat resistance and photosensitive characteristics, and more preferably a -COOR 1 group and a -COOR 2 group and a -CONH- group are aromatic groups or alicyclic aliphatic groups in ortho positions to each other. As the tetravalent organic group represented by X 1 , specifically, an organic group having 6 to 40 carbon atoms containing an aromatic ring, for example, the following general formula (20):

Chemical formula

Chemical formula

[0029] X 1 As the structure represented by, among the structures represented by the above formula (20), particularly the following formula (X1):

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0030] X 1 As the structure represented by, the following formula:

Chemical formula

[0031] In the above general formula (1), Y 1 The divalent organic group represented by is preferably an aromatic group having 6 to 40 carbon atoms in that it achieves both heat resistance and photosensitive properties. For example, the following formula (21):

Chemical formula

Chemical formula

[0032] Y 1 As the group, among the structures represented by the above formula (21), in particular, the following formula (Y1): [Chemical formula] {In the formula, each Rz is independently a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a is an integer from 0 to 4, A is an oxygen atom or a sulfur atom, and B is a single bond or the following formula: [Chemical formula] at least one group represented by.} The structure represented by is preferable from the viewpoint of reducing the dielectric tangent, and further the following formula: [Chemical formula] Or the following formula: [Chemical formula] Or the following formula: [Chemical formula] Structures represented by are preferable from the viewpoints of low dielectric tangent, low dielectric constant, and lithography properties.

[0033] R in the above general formula (2) 3 is preferably a hydrogen atom or a methyl group, R 4 and R5 is preferably a hydrogen atom from the viewpoint of photosensitive properties. Also, m 1 is an integer of 2 or more and 10 or less, preferably an integer of 2 or more and 4 or less, from the viewpoint of photosensitive properties.

[0034] In this specification, the term "imide group concentration" refers to the ratio of the mass occupied by imide groups to the molecular weight of the repeating unit containing the structure derived from tetracarboxylic acid and diamine in the polyimide of the polyimide cured film obtained by heating and curing the photosensitive resin composition according to this embodiment. In this embodiment, the imide group concentration of the obtained polyimide cured film is 12 wt% to 30 wt%, preferably 12 wt% to 24 wt%. When the imide group concentration is 12 wt% or more, the adhesion between the mold resin and the cured relief pattern tends to be good. The imide group concentration is preferably 12.5 wt% or more, more preferably 13.5 wt% or more. On the other hand, when the imide group concentration is 30 wt% or less, the dielectric tangent of the obtained polyimide cured film tends to be good. The imide group concentration is preferably 24.0 wt% or less, more preferably 23.0 wt% or less, and even more preferably 21.0 wt% or less.

[0035] The imide group concentration per repeating unit of polyimide is calculated using the molecular weights of the tetracarboxylic acid and diamine used in the preparation of the polyimide precursor by the following formula (I): 70.02×2 / [Mw(A)+Mw(B)] ×100 (I) {In formula (I), Mw(A) represents the molecular weight of the tetracarboxylic acid, and Mw(B) represents the molecular weight of the diamine.} It is represented by. When two or more types of tetracarboxylic acids and / or diamines are used, for example, when adjusting using two types of tetracarboxylic acids and / or diamines, the following formula (II): 70.02×2 / [Mw(A1)×a 1 +Mw(A2)×a 2 +Mw(B1)×b 1 +Mw(B2)×b 2 ×100 (II) In formula (II), Mw(A1) represents the molecular weight of the first tetracarboxylic acid, Mw(A2) represents the molecular weight of the second tetracarboxylic acid, a 1 represents the content of the first tetracarboxylic acid, a 2 represents the content of the second tetracarboxylic acid, Mw(B1) represents the molecular weight of the first diamine, Mw(B2) represents the molecular weight of the second diamine, b 1 represents the content of the first diamine, and b 2 represents the content of the second diamine. However, a 1 a 2 b 1 b 2 respectively satisfy a 1 +a 2 = 1, b 1 +b 2 = 1.} It is represented by When using three or more types of tetracarboxylic acids and / or diamines, it is similarly required. When using tetracarboxylic dianhydride as a raw material, it is calculated by converting it to tetracarboxylic acid.

[0036] (A) Preparation method of polyimide precursor The polyimide precursor containing the structure represented by the above general formula (1) is, for example, a tetracarboxylic dianhydride containing the tetravalent organic group X having 6 to 40 carbon atoms described above 1 and (a) alcohols having a structure in which a monovalent organic group represented by the above general formula (2) and a hydroxyl group are bonded, and optionally (b) alcohols having a structure other than the group represented by the above general formula (2) are reacted to prepare a partially esterified tetracarboxylic acid (hereinafter, also referred to as an acid / ester form); Subsequently, the obtained acid / ester form and diamines containing the divalent organic group Y having 6 to 40 carbon atoms described above 1 are polycondensed. It is obtained by a method including

[0037] (Preparation of acid / ester form) Tetravalent organic group X having 6 to 40 carbon atoms 1Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, diphenyl ether-3,3’,4,4’-tetracarboxylic dianhydride, benzophenone-3,3’,4,4’-tetracarboxylic dianhydride, biphenyl-3,3’,4,4’-tetracarboxylic dianhydride, diphenyl sulfone-3,3’,4,4’-tetracarboxylic dianhydride, diphenylmethane-3,3’,4,4’-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane, 4,4‘-(4,4’-isopropylidenediphenoxy) dianhydride, etc. These can be used alone or in combination of two or more.

[0038] (b) Examples of the alcohols having a structure other than the group represented by the general formula (2) include aliphatic alcohols having 5 to 30 carbon atoms or aromatic alcohols having 6 to 30 carbon atoms, such as 1-pentanol, 2-pentanol, 3-pentanol, neopentyl alcohol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, benzyl alcohol, etc.

[0039] By dissolving and mixing the above tetracarboxylic dianhydride and the alcohols in (a) in a reaction solvent in the presence of a basic catalyst such as pyridine, the half-esterification reaction of the dianhydride proceeds to obtain the desired acid / ester form. The reaction conditions preferably include stirring at a reaction temperature of 20 to 50°C for 4 to 10 hours.

[0040] As the above reaction solvent, those capable of dissolving the acid / ester compound and the polyimide precursor which is a polycondensation product of the acid / ester compound and diamines are preferred. Examples of the reaction solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, gamma-butyrolactone, ketones, esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, chlorobenzene, o-dichlorobenzene, hexane, heptane, benzene, toluene, xylene, and the like. These may be used alone or in combination of two or more as necessary.

[0041] (Preparation of Polyimide Precursor) To the above acid / ester compound (typically a solution in the above reaction solvent), a known dehydrating condensing agent is mixed under ice cooling to convert the acid / ester compound into a polyacid anhydride, and then, diamines containing a divalent organic group Y having 6 to 40 carbon atoms 1 dissolved or dispersed separately in a solvent are added dropwise and polycondensed to obtain a polyimide precursor. Examples of the dehydrating condensing agent include dicyclohexylcarbodiimide, 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, 1,1-carbonyldioxy-di-1,2,3-benzotriazole, N,N'-disuccinimidyl carbonate, and the like.

[0042] The divalent organic group Y having 6 to 40 carbon atoms 1Examples of diamines include p-phenylenediamine, m-phenylenediamine, 4,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, ortho-tolidine sulfone, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis{3-methyl-4-(4-aminophenoxy)phenyl}propane, bis{4-(4-aminophenoxy)phenyl}ketone, and those in which some of the hydrogen atoms on these benzene rings are substituted with a methyl group, ethyl group, hydroxymethyl group, hydroxyethyl group, halogen, etc., for example, 3,3'-dimethyl-4,4'-Diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, mixtures thereof, etc. may also be mentioned. However, the diamines are not limited to these.,

[0043] In order to improve the adhesion between the photosensitive resin layer formed on the substrate by applying the photosensitive resin composition on the substrate and various substrates, during the preparation of the (A) polyimide precursor, diaminosiloxanes such as 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(3-aminopropyl)tetraphenyldisiloxane can also be copolymerized.,

[0044] After completion of the above polycondensation reaction, the water-absorbing by-products of the dehydrating condensing agent coexisting in the reaction solution may be filtered off as necessary, and then a poor solvent such as water, a lower aliphatic alcohol, or a mixture thereof may be added to the reaction solution to precipitate the polymer component. Furthermore, the polymer may be purified by repeating the above redissolution and reprecipitation operations. Then, the polymer can be vacuum dried to isolate the polyimide precursor. In order to improve the degree of purification, the solution of this polymer may be passed through a column filled with an anion and / or cation exchange resin swollen with an appropriate organic solvent to remove ionic impurities.,

[0045] (A) The molecular weight of the polyimide precursor is preferably 8,000 to 150,000, more preferably 9,000 to 50,000, and particularly preferably 18,000 to 40,000 when measured by polystyrene-equivalent weight-average molecular weight by gel permeation chromatography. If the weight-average molecular weight is 8,000 or more, it is preferable because the mechanical properties are good. On the other hand, if it is 150,000 or less, it is preferable because the dispersibility in the developer and the resolution performance of the relief pattern are good. As the developing solvent for gel permeation chromatography, tetrahydrofuran and N-methyl-2-pyrrolidone are recommended. The molecular weight is determined from a calibration curve prepared using standard monodisperse polystyrene. As the standard monodisperse polystyrene, it is recommended to select from the organic solvent-based standard sample STANDARD SM-105 manufactured by Showa Denko K.K.

[0046] (B) Photosensitizer The photosensitive resin composition contains a photosensitizer. In one embodiment, the photosensitizer may be a photopolymerization initiator. The photopolymerization initiator is preferable for promoting the curing of the relief pattern by light irradiation. As the photopolymerization initiator, a photo radical polymerization initiator is preferably used, and benzophenone derivatives such as benzophenone, methyl o-benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone, acetophenone derivatives such as 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, thioxanthone derivatives such as thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl derivatives such as benzyl, benzyldimethyl ketal, benzyl-β-methoxyethyl acetal, benzoin derivatives such as benzoin, benzoin methyl ether, oximes such as 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, N-aryl glycines such as N-phenylglycine, peroxides such as benzoyl perchloride, aromatic biimidazoles, titanocenes, photoacid generators such as α-(n-octanesulfonyloxyimino)-4-methoxybenzyl cyanide, etc. are preferably mentioned, but are not limited thereto. Among the above photopolymerization initiators, oximes are more preferable particularly in terms of photosensitivity.

[0047] The compounding amount of the photoinitiator is preferably 0.1 part by mass or more and 10 parts by mass, more preferably 1 part by mass or more and 8 parts by mass or less, based on 100 parts by mass of the (A) polyimide precursor. The above compounding amount is preferably 0.1 part by mass or more from the viewpoint of photosensitivity or patterning property, and preferably 10 parts by mass or less from the viewpoint of the physical properties of the photosensitive resin layer after curing of the photosensitive resin composition.

[0048] (C) Solvent The photosensitive resin composition of this embodiment contains a solvent. From the viewpoint of solubility in the (A) polyimide precursor, it is preferable to use a polar organic solvent as the solvent. Specifically, examples of the solvent include N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, 2-octanone, etc. These can be used alone or in combination of two or more.

[0049] The above solvent can be used in the range of, for example, 50 parts by mass to 300 parts by mass, preferably 100 parts by mass to 300 parts by mass, based on 100 parts by mass of the (A) polyimide precursor, according to the desired coating film thickness and viscosity of the photosensitive resin composition.

[0050] From the viewpoint of improving the storage stability of the photosensitive resin composition, a solvent containing alcohols is preferred. The alcohols that can be preferably used are typically alcohols having an alcoholic hydroxyl group in the molecule and no olefinic double bond. Specific examples include alkyl alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, etc.; lactate esters such as ethyl lactate; propylene glycol monoalkyl ethers such as propylene glycol-1-methyl ether, propylene glycol-2-methyl ether, propylene glycol-1-ethyl ether, propylene glycol-2-ethyl ether, propylene glycol-1-(n-propyl) ether, propylene glycol-2-(n-propyl) ether; monoalcohols such as ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether; 2-hydroxyisobutyrate esters; and dialcohols such as ethylene glycol and propylene glycol. Among these, lactate esters, propylene glycol monoalkyl ethers, 2-hydroxyisobutyrate esters, and ethyl alcohol are preferred, and ethyl lactate, propylene glycol-1-methyl ether, propylene glycol-1-ethyl ether, and propylene glycol-1-(n-propyl) ether are more preferred.

[0051] When the solvent contains an alcohol having no olefinic double bond, the content of the alcohol having no olefinic double bond in the total solvent is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 30% by mass, based on the mass of the total solvent. When the above content of the alcohol having no olefinic double bond is 5% by mass or more, the storage stability of the photosensitive resin composition becomes good. On the other hand, when it is 50% by mass or less, it is preferable because the solubility of the (A) polyimide precursor becomes good.

[0052] [Other components] The photosensitive resin composition may further contain components other than the above components (A), (B), and (C). Examples of other components include resin components other than the (A) polyimide precursor; sensitizers; monomers having a photopolymerizable unsaturated bond; auxiliary agents; thermal polymerization inhibitors; azole compounds; and hindered phenol compounds.

[0053] The photosensitive resin composition may further contain a resin component other than the (A) polyimide precursor. Examples of resin components that can be contained in the photosensitive resin composition include polyimide, polyoxazole, polyoxazole precursor, phenol resin, polyamide, epoxy resin, siloxane resin, acrylic resin, etc. The blending amount of these resin components is preferably in the range of 0.01 parts by mass to 20 parts by mass with respect to 100 parts by mass of the (A) polyimide precursor.

[0054] When preparing a positive photosensitive resin composition using a polyoxazole precursor together with the (A) polyimide precursor, as the positive photosensitive material, a compound having a quinonediazide group, for example, a compound having a 1,2 - benzoquinonediazide structure or a 1,2 - naphthoquinonediazide structure, etc. may be used in combination.

[0055] The photosensitive resin composition can optionally contain a sensitizer to improve photosensitivity. Examples of the sensitizer include Michler's ketone, 4,4'-bis(diethylamino)benzophenone, 2,5-bis(4'-diethylaminobenzal)cyclopentane, 2,6-bis(4'-diethylaminobenzal)cyclohexanone, 2,6-bis(4'-diethylaminobenzal)-4-methylcyclohexanone, 4,4'-bis(dimethylamino)chalcone, 4,4'-bis(diethylamino)chalcone, p-dimethylaminocinnamylidene indanone, p-dimethylaminobenzylidene indanone, 2-(p-dimethylaminophenylbiphenylene)-benzothiazole, 2-(p-dimethylaminophenylvinylene)benzothiazole, 2-(p-dimethylaminophenylvinylene)isonaphthothiazole, 1,3-bis(4'-dimethylaminobenzal)acetone, 1,3-bis(4'-diethylaminobenzal)acetone, 3,3'-carbonyl-bis(7-diethylaminocoumarin), 3-acetyl-7-dimethylaminocoumarin, 3-ethoxycarbonyl-7-dimethylaminocoumarin, 3-benzyloxycarbonyl-7-dimethylaminocoumarin, 3-methoxycarbonyl-7-diethylaminocoumarin, 3-ethoxycarbonyl-7-diethylaminocoumarin, N-phenyl-N'-ethylethanolamine, N-phenyldiethanolamine, N-p-tolyldiethanolamine, N-phenylethanolamine, 4-morpholinobenzophenone, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzothiazole, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 2-(p-dimethylaminostyryl)naphtho(1,2-d)thiazole, 2-(p-dimethylaminobenzoyl)styrene, and the like. These can be used alone or in combination of two or more (for example, 2 to 5 types).

[0056] The compounding amount of the sensitizer is preferably 0.1 part by mass to 25 parts by mass with respect to 100 parts by mass of the (A) polyimide precursor.

[0057] In order to improve the resolution of the relief pattern, the photosensitive resin composition can optionally contain a monomer having a photopolymerizable unsaturated bond. Such monomers are preferably (meth)acrylic compounds that undergo radical polymerization by a photopolymerization initiator, and particularly include, but are not limited to, ethylene glycol or polyethylene glycol mono- or diacrylate or methacrylate such as diethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate, propylene glycol or polypropylene glycol mono- or diacrylate or methacrylate, glycerol mono-, di- or triacrylate or methacrylate, cyclohexane diacrylate or dimethacrylate, 1,4-butanediol diacrylate or dimethacrylate, 1,6-hexanediol diacrylate or dimethacrylate, neopentyl glycol diacrylate or dimethacrylate, bisphenol A mono- or diacrylate or methacrylate, benzene trimethacrylate, isobornyl acrylate or methacrylate, acrylamide, its derivatives, methacrylamide, its derivatives, trimethylolpropane triacrylate or methacrylate, glycerol di- or triacrylate or methacrylate, pentaerythritol di-, tri- or tetraacrylate or methacrylate, and compounds such as ethylene oxide or propylene oxide adducts of these compounds. These monomers may be used alone or as a mixture of two or more.

[0058] The blending amount of the monomer having a photopolymerizable unsaturated bond is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the (A) polyimide precursor.

[0059] In order to improve the adhesion between the film formed using the photosensitive resin composition and the substrate, the photosensitive resin composition can optionally contain an adhesion promoter. Examples of the adhesion promoter include silane coupling agents such as γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxy-3-glycidoxypropylmethylsilane, N-(3-diethoxymethylsilylpropyl)succinimide, N-[3-(triethoxysilyl)propyl]phthalic acid, benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamide)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-[3-triethoxysilyl]propylamide)-2,5-dicarboxylic acid, 3-(triethoxysilyl)propyl succinic anhydride, N-phenylaminopropyltrimethoxysilane, etc., and aluminum-based adhesion promoters such as aluminum tris(ethylacetoacetate), aluminum tris(acetylacetonate), ethylacetoacetate aluminum diisopropylate, etc. Also, these adhesion promoters may be used alone or as a mixture of two or more.

[0060] Among these adhesion promoters, it is more preferable to use a silane coupling agent from the viewpoint of adhesion strength. The blending amount of the adhesion promoter is preferably in the range of 0.5 parts by mass to 25 parts by mass with respect to 100 parts by mass of the (A) polyimide precursor.

[0061] In order to improve the viscosity and light sensitivity stability of the photosensitive resin composition, especially when stored in the state of a solution containing a solvent, the photosensitive resin composition can optionally contain a thermal polymerization inhibitor. Examples of the thermal polymerization inhibitor include hydroquinone, N-nitrosodiphenylamine, p-tert-butylcatechol, phenothiazine, N-phenylnaphthylamine, ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, glycol ether diamine tetraacetic acid, 2,6-di-tert-butyl-p-methylphenol, 5-nitroso-8-hydroxyquinoline, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 2-nitroso-5-(N-ethyl-N-sulfopropylamino)phenol, N-nitroso-N-phenylhydroxylamine ammonium salt, N-nitroso-N(1-naphthyl)hydroxylamine ammonium salt, and the like. These thermal polymerization inhibitors may be used alone or as a mixture of two or more.

[0062] As the blending amount of the thermal polymerization inhibitor, the range of 0.005 parts by mass to 12 parts by mass is preferable with respect to 100 parts by mass of the (A) polyimide precursor.

[0063] For example, when using a substrate made of copper or a copper alloy, in order to suppress substrate discoloration, the photosensitive resin composition can optionally contain an azole compound. Examples of the azole compound include 1H-triazole, 5-methyl-1H-triazole, 5-ethyl-1H-triazole, 4,5-dimethyl-1H-triazole, 5-phenyl-1H-triazole, 4-t-butyl-5-phenyl-1H-triazole, 5-hydroxyphenyl-1H-triazole, phenyltriazole, p-ethoxyphenyltriazole, 5-phenyl-1-(2-dimethylaminoethyl)triazole, 5-benzyl-1H-triazole, hydroxyphenyltriazole, 1,5-dimethyltriazole, 4,5-diethyl-1H-triazole, 1H-benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, hydroxyphenylbenzotriazole, tolyltriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H-benzotriazole, 4-carboxy-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 1-methyl-1H-tetrazole, and the like. Particularly preferred are tolyltriazole, 5-methyl-1H-benzotriazole, and 4-methyl-1H-benzotriazole. These azole compounds may be used alone or as a mixture of two or more.

[0064] The compounding amount of the azole compound is preferably 0.1 part by mass to 20 parts by mass, more preferably 0.5 part by mass to 5 parts by mass, based on 100 parts by mass of the (A) polyimide precursor. When the compounding amount of the azole compound is 0.1 part by mass or more based on 100 parts by mass of the (A) polyimide precursor, discoloration of the surface of copper or a copper alloy is suppressed when the photosensitive resin composition is formed on copper or a copper alloy. On the other hand, when it is 20 parts by mass or less, it is preferable because of excellent photosensitivity.

[0065] To suppress the discoloration of copper, the photosensitive resin composition can contain a hindered phenol compound. Examples of the hindered phenol compound include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butyl-hydroquinone, octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-thio-bis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2'-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], tris(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-isopropylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-s-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-(1-ethylpropyl)-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione,

[0066] 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-phenylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5,6-trimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5,6-diethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione and the like can be mentioned, but are not limited thereto. Among these, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione is particularly preferred.

[0067] The compounding amount of the hindered phenol compound is preferably 0.1 part by mass to 20 parts by mass, more preferably 0.5 part by mass to 10 parts by mass, based on 100 parts by mass of the polyimide precursor (A). When the compounding amount of the hindered phenol compound with respect to 100 parts by mass of the polyimide precursor (A) is 0.1 part by mass or more, for example, when a photosensitive resin composition is formed on copper or a copper alloy, discoloration and corrosion of the copper or copper alloy are prevented. On the other hand, when it is 20 parts by mass or less, it is preferable because of excellent photosensitivity.

[0068] The photosensitive resin composition may contain an organic compound containing a metal element selected from titanium or zirconium. The organic compound preferably contains one metal element selected from titanium or zirconium in one molecule. The organic group preferably includes a hydrocarbon group and a hydrocarbon group containing a hetero atom. By containing the organic compound, the imidization rate of the photosensitive resin composition increases and the dielectric tangent of the cured film decreases.

[0069] Examples of usable organic titanium or zirconium compounds include those in which an organic chemical substance is bonded to a titanium or zirconium atom via a covalent bond or an ionic bond.

[0070] Specific examples of the organic titanium or zirconium compound are shown in the following I) to VII): I) As the chelate compound, a compound having two or more alkoxy groups is more preferable because of the storage stability of the photosensitive resin composition and the ability to obtain a good pattern. Specific examples of the chelate compound include titanium bis(triethanolamine) diisopropoxide, titanium di(n-butoxide) bis(2,4-pentanedionate), titanium diisopropoxide bis(2,4-pentanedionate), titanium diisopropoxide bis(tetramethylheptanedionate), titanium diisopropoxide bis(ethyl acetoacetate), and compounds in which the titanium atom of these compounds is replaced with a zirconium atom, but are not limited thereto.

[0071] II) Examples of the tetraalkoxy compound include, but are not limited to, titanium tetra(n-butoxide), titanium tetraethoxide, titanium tetra(2-ethylhexoxide), titanium tetraisobutoxide, titanium tetraisopropoxide, titanium tetramethoxide, titanium tetramethoxypropoxide, titanium tetramethylphenoxide, titanium tetra(n-nonoxide), titanium tetra(n-propoxide), titanium tetrastearate, titanium tetrakis[bis{2,2-(allyloxymethyl)butoxide}], and compounds in which the titanium atom of these compounds is substituted with a zirconium atom.

[0072] III) Examples of the titanocene or zirconocene compound include, but are not limited to, pentamethylcyclopentadienyltitanium trimethoxide, bis(η 5 -2,4-cyclopentadien-1-yl)bis(2,6-difluorophenyl)titanium, bis(η 5 -2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, and compounds in which the titanium atom of these compounds is substituted with a zirconium atom.

[0073] IV) Examples of the monoalkoxy compound include, but are not limited to, titanium tris(dioctyl phosphate) isopropoxide, titanium tris(dodecylbenzenesulfonate) isopropoxide, and compounds in which the titanium atom of these compounds is substituted with a zirconium atom.

[0074] V) Examples of the titanium oxide or zirconium oxide compound include, but are not limited to, titanium oxide bis(pentanedionate), titanium oxide bis(tetramethylheptanedionate), phthalocyanine titanium oxide, and compounds in which the titanium atom of these compounds is substituted with a zirconium atom.

[0075] VI) Examples of the titanium tetraacetylacetonate or zirconium tetraacetylacetonate compound include, but are not limited to, titanium tetraacetylacetonate and compounds in which the titanium atoms of these compounds are substituted with zirconium atoms.

[0076] VII) Examples of the titanate coupling agent include, but are not limited to, isopropyltridodecylbenzenesulfonyl titanate.

[0077] Among the above I) to VII), it is preferable from the viewpoint of exhibiting better dielectric loss tangent that the organic titanium compound is at least one compound selected from the group consisting of the above I) titanium chelate compound, II) tetraalkoxytitanium compound, and III) titanocene compound. In particular, titanium diisopropoxide bis(ethylacetoacetate), titanium tetra(n-butoxide), and bis(η 5 -2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium are preferable.

[0078] When blending the organic titanium or zirconium compound, the blending amount is preferably 0.05 parts by mass to 10 parts by mass, and more preferably 0.1 parts by mass to 2 parts by mass with respect to 100 parts by mass of the (A) resin. If the blending amount is 0.05 parts by mass or more, the imidization rate of the good photosensitive resin composition and the dielectric loss tangent of the cured film are exhibited. On the other hand, if it is 10 parts by mass or less, it is preferable because the storage stability of the photosensitive resin composition is excellent.

[0079] [Polyimide] The structure of the polyimide contained in the cured relief pattern (polyimide cured film) formed from the above polyimide precursor composition is represented by the following general formula (11):

Chemical formula

[0080] Another embodiment of the present invention is that the weight loss rate when heated to 320 ° C is 0.01% to 0.5%, the weight loss rate when heated to 350 ° C is 0.1% to 1.5%, and the dielectric loss tangent when measured at a frequency of 40 GHz by the perturbation method split cylinder resonator method is 0.0021 to 0.0085, which is the polyimide cured film itself for forming an interlayer insulating film for rewiring.

[0081] [Semiconductor device] Still another embodiment of the present invention is a semiconductor device having a cured relief pattern obtained by the method for manufacturing the cured relief pattern described above, that is, a semiconductor device having a substrate that is a semiconductor element and a cured relief pattern of polyimide formed on the substrate by the method for manufacturing the cured relief pattern described above. Further, the method for manufacturing a polyimide cured film according to the present invention can also be applied to a method for manufacturing a semiconductor device that uses a semiconductor element as a substrate and includes the method for manufacturing the cured relief pattern described above as part of the process. The semiconductor device of this embodiment can be manufactured by forming the cured relief pattern formed by the above-described cured relief pattern manufacturing method as a surface protection film, an interlayer insulating film, a rewiring insulating film, a protection film for a flip chip device, a protection film for a semiconductor device having a bump structure, etc., and combining it with a known semiconductor device manufacturing method.

[0082] [Display device] Still other embodiments of the present invention are display devices including display pixels and a cured film provided on top of the display pixels, where the cured film is the above-described cured relief pattern. Here, the cured relief pattern may be laminated in direct contact with the display pixels, or may be laminated with another layer interposed therebetween. For example, examples of the cured film include surface protective films, insulating films, planarization films, protrusions for MVA type liquid crystal display devices, and partitions for organic EL element cathodes of TFT liquid crystal display elements and color filter elements.

[0083] The method for manufacturing a polyimide cured film according to the present invention is useful not only for application to semiconductor devices as described above, but also for applications such as interlayer insulation of multilayer circuits, cover coating of flexible copper clad laminates, solder resist films, and liquid crystal alignment films.

Examples

[0084] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples. In the examples, comparative examples, and production examples, various physical properties and the like were measured and evaluated using the following measurement and evaluation methods.

[0085] [Measurement and Evaluation Methods] (1) Weight average molecular weight The weight average molecular weight (Mw) of each resin was measured by gel permeation chromatography (standard polystyrene conversion). The column used for the measurement was the trade name "Shodex 805M / 806M series" manufactured by Showa Denko K.K., the standard monodisperse polystyrene was the trade name "Shodex STANDARD SM-105" manufactured by Showa Denko K.K., the developing solvent was N-methyl-2-pyrrolidone, and the detector was the trade name "Shodex RI-930" manufactured by Showa Denko K.K.

[0086] (2) Measurement of dielectric constant (Dk) and dielectric loss tangent (Df) On a 6-inch silicon wafer (manufactured by Fujimi Electronics Industry Co., Ltd., thickness 625 ± 25 μm), 100 nm thick aluminum (Al) was sputtered using a sputtering apparatus (L-440S-FHL type, manufactured by Canon Anelva Corporation) to prepare a sputtered Al wafer substrate. A negative photosensitive resin composition was spin-coated onto the above sputtered Al wafer substrate using a spin coater (D-spin60A type, manufactured by SOKUDO Co., Ltd.), and heat-dried at 110 °C for 3 minutes to form a spin-coated film. Then, the entire surface was exposed with ghi-line at an exposure dose of 600 mJ / cm2 using an aligner (PLA-501F, manufactured by Canon Inc.), and heat-cured at a predetermined temperature for 2 hours in a nitrogen atmosphere using a vacuum gas replacement oven (450PB8-2P-CP, manufactured by YES Co., Ltd.) to form a cured film. The film thickness of the cured film was measured using a step gauge (P-15, manufactured by KLA-Tencor Corporation). This cured film was cut into a size of 80 mm in length and 60 mm in width, or 40 mm in length and 30 mm in width using a dicing saw (manufactured by DISCO, model name DAD-2H / 6T), immersed in a 10% hydrochloric acid aqueous solution to peel it off from the silicon wafer, and used as a film sample.

[0087] The relative permittivity and dielectric loss tangent of the film sample at 10, 28, 40, and 60 GHz were calculated by the resonator perturbation method. The details of the measurement method were as follows. (Measurement method) Perturbation method: Split cylinder resonator method (Device configuration) Network analyzer: PNA Network analyzer E5224B (Manufactured by Agilent technologies) Split cylinder resonator: CR-710 (manufactured by Kanto Electronic Application Development Co., Ltd., measurement frequency: about 10 GHz), CR-728 (manufactured by Kanto Electronic Application Development Co., Ltd., measurement frequency: about 28 GHz), CR-740 (manufactured by Kanto Electronic Application Development Co., Ltd., measurement frequency: about 40 GHz), CR-760 (manufactured by Kanto Electronic Application Development Co., Ltd., measurement frequency: about 60 GHz)

[0088] (3) Measurement of weight loss rate A photosensitive resin composition was spin-coated on a 6-inch silicon wafer so that the film thickness after curing would be about 10 μm. After pre-baking on a hot plate at 110 °C for 180 seconds, it was heated at 230 °C for 2 hours in a nitrogen atmosphere using a vacuum gas replacement oven (450PB8-2P-CP, manufactured by YES Corporation) to obtain a cured polyimide coating film. The film thickness was measured using a film thickness measuring device, Lambda Ace (manufactured by Dainippon Screen Co., Ltd.). The obtained polyimide coating film was scraped off, and when the temperature was raised from room temperature at 10 °C / min using a thermogravimetric analyzer (TGA-50, manufactured by Shimadzu Corporation), the weight of the film when it reached 230 °C was W 230 , the weight of the film when it reached 320 °C was W 320 , and the weight of the film when it reached 350 °C was W 350 . Then, the following formulas: 320 °C weight loss rate (%) = (W 230 - W 320 ) / W 230 350 °C weight loss rate (%) = (W 230 - W 350 ) / W 230 were calculated respectively.

[0089] [(A) Production of polyimide precursor] <Production Example 1> ((A) Synthesis of polyimide precursor (Polymer A-1)) 155.1 g of 4,4'-oxydiphthalic dianhydride (ODPA) was placed in a 2-liter separable flask, 134.0 g of 2-hydroxyethyl methacrylate (HEMA) and 400 ml of γ-butyrolactone were added, and 79.1 g of pyridine was added while stirring at room temperature to obtain a reaction mixture. After the exothermic reaction ended, it was allowed to cool to room temperature and further allowed to stand for 16 hours.

[0090] Next, under ice-cooling, a solution prepared by dissolving 206.3 g of dicyclohexylcarbodiimide (DCC) in 180 ml of γ-butyrolactone was added to the reaction mixture over 40 minutes with stirring. Subsequently, a suspension prepared by suspending 175.9 g of 2,2-bis{4-(4-aminophenoxy)phenyl}propane (BAPP) in 350 ml of γ-butyrolactone was added over 60 minutes with stirring. After further stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added and stirred for 1 hour, and then 400 ml of γ-butyrolactone was added. The precipitate formed in the reaction mixture was removed by filtration to obtain a reaction solution.

[0091] The obtained reaction solution was added to 3 liters of ethyl alcohol to form a precipitate composed of a crude polymer. The formed crude polymer was collected by filtration and dissolved in 1.5 liters of tetrahydrofuran to obtain a crude polymer solution. The obtained crude polymer solution was purified using an anion exchange resin ("Amberlyst TM 15" manufactured by Organo Corporation) to obtain a polymer solution. The obtained polymer solution was dropped into 28 liters of water to precipitate the polymer. The obtained precipitate was collected by filtration and then vacuum-dried to obtain powdery polymer A-1. When the weight average molecular weight (Mw) of this polymer A-1 was measured, it was 22,000. The imide group concentration per repeating unit of the polyimide cured film obtained from polymer A-1 was 19.4 wt%.

[0092] <Production Example 2> ((Synthesis of (A) polyimide precursor (polymer A-2))) In the above Production Example 1, a reaction was carried out in the same manner as the method described in Production Example 1, except that 93.0 g of 4,4'-oxydianiline (ODA) was used instead of 175.9 g of BAPP, to obtain polymer A-2. When the weight average molecular weight (Mw) of this polymer A-2 was measured, it was 22,000. The imide group concentration per repeating unit of the polyimide cured film obtained from polymer A-2 was 27.4 wt%.

[0093] <Production Example 3> ((Synthesis of (A) polyimide precursor (polymer A-3))) In Production Example 1 described above, a reaction was carried out in the same manner as the method described in Production Example 1, except that 260.2 g of 4,4'-(4,4'-isopropylidenediphenoxy) dianhydride (BPADA) was used instead of 155.1 g of ODPA, and 92.88 g of 2,2'-dimethylbiphenyl-4,4'-diamine (m-TB) was used instead of 175.9 g of BAPP, to obtain Polymer A-3. When the weight average molecular weight (Mw) of this Polymer A-3 was measured, it was 23,000. The imide group concentration per repeating unit of the polyimide cured film obtained from Polymer A-3 was 19.1 wt%.

[0094] <Production Example 4> ((A) Synthesis of polyimide precursor (Polymer A-4)) In Production Example 1 described above, a reaction was carried out in the same manner as the method described in Production Example 1, except that 109.1 g of pyromellitic dianhydride was used instead of 155.1 g of ODPA, and 93.0 g of ODA was used instead of 175.9 g of BAPP, to obtain Polymer A-4. When the weight average molecular weight (Mw) of this Polymer A-4 was measured, it was 20,000. The imide group concentration per repeating unit of the polyimide cured film obtained from Polymer A-4 was 33.5 wt%.

[0095] [Production of photosensitive resin composition] The following compounds were used in the examples. Photoinitiator B-1: TR-PBG-3057 (manufactured by Changzhou Qiangli Electronics Co., Ltd.) Solvent D-1: γ-butyrolactone (GBL)

[0096] <Example 1> A negative photosensitive resin composition was prepared by the following method using polyimide precursor A-1. (A) 100 g of A-1 as the polyimide precursor, (B) 5 g of B-1 as the photoinitiator, and (D) dissolved in 100 g of D-1. The viscosity of the resulting solution was adjusted to about 40 poise by further adding a small amount of GBL to obtain a negative photosensitive resin composition. A cured film was prepared and evaluated according to the above-described method. The heat curing step (step (5)) was carried out at 230 °C for 2 hours under a pressure of 380 torr. The results are shown in Table 1 below.

[0097] <Examples 1 to 7, Comparative Examples 1 to 4> Adjusted at the mixing ratios shown in Table 1 below, and the same evaluation as in Example 1 was carried out using the temperature and pressure of the heat curing step shown in Table 1.

[0098] <Examples 8, 9> Prepared at the mixing ratios shown in Table 1 below, and the same evaluation as in Example 1 was carried out using the pressure shown in Table 1. The heat curing step was carried out at 150 °C for 1 hour, and then the temperature was raised to 230 °C for 1 hour.

[0099]

Table 1

[0100] As can be seen from Table 1, in the cured films of the examples, cured films with low frequency dependence of the dielectric tangent could be obtained. Also, compared to the comparative examples, the weight loss rate when the cured film was heated to 320 °C and 350 °C decreased.

Industrial Applicability

[0101] According to the method for producing a polyimide cured film according to the present invention, it is possible to provide a cured film having low frequency dependence of the dielectric tangent and suppressed thermal weight loss at temperatures above the heat curing temperature. Therefore, the method for producing a polyimide cured film according to the present invention can be suitably used, for example, in fields such as semiconductor devices and multilayer wiring boards.

Claims

1. The following steps: (1) A step of applying a photosensitive resin composition containing a polyimide precursor onto a substrate to form a photosensitive resin layer on the substrate; (2) A step of drying and heating the obtained photosensitive resin layer; (3) A step of exposing the obtained photosensitive resin layer; (4) A step of developing the obtained photosensitive resin layer; and (5) A step of heat-treating the photosensitive resin layer remaining on the substrate at 150°C to 250°C to form a cured film; A method for producing a polyimide cured film, comprising: wherein the step (2) and / or (5) is carried out under a pressure of 50 torr or more and 580 torr or less, and in the polyimide of the obtained polyimide cured film, the imide group concentration, which is the ratio occupied by the imide group with respect to the molecular weight of the repeating unit containing the structure derived from tetracarboxylic acid and diamine, is 12 wt% to 30 wt%.

2. The method for producing a polyimide cured film according to claim 1, wherein the dielectric loss tangent at a frequency of 10 GHz by the perturbation-mode split-cylinder resonator method of the cured film obtained in step (5) is 0.001 to 0.

007.

3. The method for producing a polyimide cured film according to claim 1 or 2, wherein the step (5) is carried out under a pressure of 50 torr or more and 580 torr or less.

4. The method for producing a polyimide cured film according to claim 3, wherein when the set heating and curing temperature is reached in the step (5), the temperature change from the set temperature is 30.0°C or less.

5. The method for producing a polyimide cured film according to claim 3 or 4, wherein in the region where the temperature change in the step (5) is 9.5°C / min or less, the pressure change is within 150 torr.

6. The method for producing a polyimide cured film according to any one of claims 1 to 5, wherein the weight loss rate when the obtained polyimide cured film is heated to 320°C is 0.01% to 0.5%.

7. The method for producing a polyimide cured film according to any one of claims 1 to 6, wherein the weight loss rate when the obtained polyimide cured film is heated to 350°C is 0.1% to 1.5%.

8. The obtained polyimide cured film has the following formula (i): 0.001 < (tanδ40 - tanδ10) / tanδ10 < 0.2 (i) {In the formula, tanδ40 is the dielectric loss tangent at a frequency of 40 GHz by the perturbation method split cylinder resonator method, and tanδ10 is the dielectric loss tangent at a frequency of 10 GHz by the perturbation method split cylinder resonator method.} The method for producing a polyimide cured film according to any one of claims 1 to 7, which satisfies the above.

9. The polyimide precursor is represented by the following general formula (1): 【Chemical 3】 {In the formula, X 1 is a tetravalent organic group having 6 to 40 carbon atoms, Y 1 is a divalent organic group having 6 to 40 carbon atoms, n 1 is an integer of 2 to 150, and R 1 and R 2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. However, at least one of R 1 and R 2 is represented by the following general formula (2): 【Chemical Formula 4】 (wherein R 3 , R 4 and R 5 are each independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and m 1 is an integer of 2 to 10).) A method for producing a polyimide cured film according to any one of claims 1 to 8, having a structure represented by {}.

10. The method for producing a polyimide cured film according to any one of claims 1 to 9, wherein the photosensitive resin composition contains a photoinitiator.

11. In the general formula (1), X 1 is the following formula: 【Chemical Formula 5】 【Chemical Formula 6】 {In the formula, R6 is a monovalent group selected from the group consisting of a hydrogen atom, a fluorine atom, a C1-C10 hydrocarbon group, and a C1-C10 fluorinated hydrocarbon group, l is an integer selected from 0 to 2, m is an integer selected from 0 to 3, and n is an integer selected from 0 to 4.} The method for producing a polyimide cured film according to claim 9, which is at least one of the structures represented by the above.

12. In the general formula (1), X 1 is the following formula: [Chemical Formula 7] {In the formula, * represents a connecting portion.} The method for producing a polyimide cured film according to claim 9, which is at least one of the structures represented by the above.

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