Multilayer polyimide film and method for manufacturing same

Abstract

The present invention relates to a multilayer polyimide film with improved plating adhesion and a method for manufacturing same and, more specifically, to a multilayer polyimide film and a method for manufacturing same, wherein the multilayer polyimide film has excellent room-temperature and heat-resistant plating adhesion even with a very thin thickness by comprising a non-thermoplastic polyimide layer and a thermoplastic polyimide layer coated on one or both surfaces of the non-thermoplastic polyimide layer.

Description

Multilayer polyimide film and method for manufacturing the same

[0001] The present invention relates to a multilayer polyimide film with improved plating adhesion and a method for manufacturing the same. More specifically, the invention relates to a multilayer polyimide film having excellent room temperature and heat-resistant plating adhesion even at very thin thicknesses, comprising a non-thermoplastic polyimide layer and a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer, and a method for manufacturing the same.

[0002] Polyimide (PI) is a polymer material based on an imide ring with excellent chemical stability and a rigid aromatic main chain, and possesses the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials.

[0003] In particular, it is gaining attention as a high-performance polymer material across fields such as electrical, electronic, and optical industries due to its excellent electrical properties, such as outstanding insulation characteristics and low dielectric constant.

[0004] Recently, as electronic products become lighter and smaller, highly integrated and flexible thin circuit boards are being actively developed.

[0005] There is a growing trend to utilize a structure in which circuits containing metal foil are formed on a polyimide film that is flexible while possessing excellent heat resistance, low-temperature resistance, and insulation properties.

[0006] Flexible metal foil laminates are primarily used for such thin circuit boards; for example, this includes Flexible Copper Clad Laminate (FCCL), which uses a thin copper sheet as the metal foil. In addition, polyimide is also utilized as a protective film or insulating film for thin circuit boards.

[0007] Flexible metal foil laminates, a type of thin circuit board, are used as a key material capable of realizing flexible yet high-density circuits in response to the lightweighting and miniaturization of electronic products. In particular, metal foil (e.g., copper foil), a component of flexible metal foil laminates, provides highly reliable electrical connections, while polyimide film is used as a support and insulating layer for the metal foil, offering excellent heat resistance and durability. However, the adhesion between the metal foil and the polyimide film has a decisive impact on the performance and durability of the thin circuit board.

[0008] Currently, high-vacuum deposition technologies, such as sputtering, are widely used to form metal layers in thin circuit boards. While this process is suitable for high-density circuit designs as it allows for the deposition of metal with a fine and uniform thickness, it presents a technical challenge in that it is difficult to reliably ensure adhesion between the deposited metal layer and the polyimide film. In particular, if the adhesion between the metal layer and the substrate is insufficient, the metal layer may delaminate due to thermal or mechanical stress, or circuit reliability may be compromised. This issue becomes even more severe in the case of ultra-thin circuit boards, making the securing of stable adhesion even more critical.

[0009] For example, if the polyimide film used in thin circuit boards has low plating adhesion, there is a high possibility that it will cause critical product defects, such as short circuits in the circuit wiring, when the circuit board is exposed to harsh external environments.

[0010] Therefore, there is a need to develop polyimide films that possess excellent plating adhesion even in room temperature and high temperature environments.

[0011] The present invention aims to solve the problems of the aforementioned prior art and has the technical objective of providing a multilayer polyimide film having excellent room temperature and heat-resistant plating adhesion even at a very thin thickness, and a method for manufacturing the same, by comprising a non-thermoplastic polyimide layer and a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer.

[0012] In order to achieve the above-mentioned technical problem, according to one aspect of the present invention, a non-thermoplastic polyimide layer; A multilayer polyimide film comprising: a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer; wherein the thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and when a copper foil is formed on the opposite side of one side of the thermoplastic polyimide layer in contact with the non-thermoplastic polyimide layer, at a thickness of 12 μm of the copper foil, the room temperature plating adhesion is 0.8 kgf / cm or more and the heat-resistant plating adhesion is 0.8 kgf / cm or more, wherein the room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and the heat-resistant plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film having the copper foil formed thereon at 150°C for 30 minutes twice and at 240°C for 10 minutes once. A multilayer polyimide film is provided, which has adhesive strength between polyimide layers.

[0013] According to another aspect of the present invention, a non-thermoplastic polyimide layer; and a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer; wherein the thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and when a copper foil is formed on the opposite side of one side of the thermoplastic polyimide layer in contact with the non-thermoplastic polyimide layer, the thickness of the copper foil is 12 μm, the room temperature plating adhesion strength is 0.8 kgf / cm or more, and the heat-resistant plating adhesion strength is 0.8 kgf / cm or more, as a multilayer polyimide film, wherein the room temperature plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature, and the heat-resistant plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film having the copper foil formed thereon at 150°C for 30 minutes twice and at 240°C for 10 minutes once. A multilayer polyimide film is provided, wherein the adhesion between polyimide layers is such that the multilayer polyimide film is manufactured by heat-treating the thermoplastic polyimide layer after the thermoplastic polyimide layer is formed on one or both sides of the non-thermoplastic polyimide layer.

[0014] According to another aspect of the present invention, the method comprises the steps of: preparing a non-thermoplastic polyimide layer (1); coating a thermoplastic polyimide layer with a thickness of 0.5 to 2.5 μm on one or both sides of the non-thermoplastic polyimide layer (2); A method for manufacturing a multilayer polyimide film is provided, comprising the step (3) of heat-treating the thermoplastic polyimide layer to produce a multilayer polyimide film, wherein when a copper foil is formed on the opposite side of one surface of the thermoplastic polyimide layer that is in contact with the non-thermoplastic polyimide layer, the thickness of the copper foil is 12 μm, the room temperature plating adhesion is 0.8 kgf / cm or more, and the heat-resistant plating adhesion is 0.8 kgf / cm or more, the room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and the heat-resistant plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film on which the copper foil is formed at 150°C for 30 minutes twice and at 240°C for 10 minutes once.

[0015] The multilayer polyimide film according to the present invention has excellent room temperature and heat-resistant plating adhesion even at very thin thicknesses.

[0016] A thin circuit board comprising the multilayer polyimide film of the present invention, which has excellent room temperature and heat-resistant plating adhesion, can reduce the occurrence of critical product defects such as short circuits in circuit wiring in room temperature and high temperature environments, and can realize high-frequency high-speed communication.

[0017] FIG. 1 schematically illustrates a multilayer polyimide film of the present invention comprising a non-thermoplastic polyimide layer (100); and a thermoplastic polyimide layer (200) coated on one side of the non-thermoplastic polyimide layer (100).

[0018] FIG. 2 schematically illustrates a multilayer polyimide film of the present invention comprising a non-thermoplastic polyimide layer (100); and thermoplastic polyimide layers (200, 200') coated on both sides of the non-thermoplastic polyimide layer (100).

[0019] Hereinafter, embodiments and examples of the present invention are described in detail so that those skilled in the art to which the present invention pertains can easily implement it. However, the present invention may be embodied in various different forms and is not limited to the embodiments and examples described herein. Throughout this specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0020] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0021] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0022] In the present specification, "a to b" indicating a numerical range is defined as ≥a and ≤b.

[0023] A multilayer polyimide film according to one aspect of the present invention comprises: a non-thermoplastic polyimide layer; and a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer; wherein the thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and when a copper foil is formed on the opposite side of one side of the thermoplastic polyimide layer that is in contact with the non-thermoplastic polyimide layer, the thickness of the copper foil is 12 μm, and the room temperature plating adhesion strength is 0.8 kgf / cm or more, and the heat-resistant plating adhesion strength is 0.8 kgf / cm or more.

[0024] In one embodiment, the multilayer polyimide film of the present invention may have a thermoplastic polyimide layer (200) coated on one side of a non-thermoplastic polyimide layer (100) as shown in FIG. 1, or may have thermoplastic polyimide layers (200, 200') coated on both sides of a non-thermoplastic polyimide layer (100) as shown in FIG. 2.

[0025] The thickness of each thermoplastic polyimide layer formed on one or both sides of the above multilayer polyimide film may be 0.5 μm or more, 0.6 μm or more, 0.8 μm or more, 1.0 μm or more, 1.2 μm or more, or 1.4 μm or more, and may be 2.5 μm or less, 2.2 μm or less, 2 μm or less, 1.8 μm or less, or 1.6 μm or less, for example, 0.5 to 2.5 μm, 0.8 to 2.2 μm, or 1.0 to 1.8 μm. Accordingly, the thickness of the thermoplastic polyimide layer formed on one side of the multilayer polyimide film may be 0.5 to 2.5 μm, and the total thickness of the thermoplastic polyimide layers formed on both sides of the multilayer polyimide film may be 1.0 to 5.0 μm.

[0026]

[0027] When a copper foil is formed on the opposite side of one side of a thermoplastic polyimide layer that is in contact with the above-mentioned non-thermoplastic polyimide layer, and the thickness of the copper foil is 12 μm, the room temperature plating adhesion of the multilayer polyimide film of the present invention may be, for example, 0.8 kgf / cm or more, 0.84 kgf / cm or more, or 0.88 kgf / cm or more, and the upper limit may be 1.5 kgf / cm or less, although the upper limit is not specifically limited.

[0028] In addition, the heat-resistant plating adhesion strength of the multilayer polyimide film of the present invention may be 0.8 kgf / cm or more, 0.82 kgf / cm or more, or 0.84 kgf / cm or more, and the upper limit may be 1.5 kgf / cm or less, although the upper limit is not specifically limited.

[0029] Here, room temperature plating adhesion and heat-resistant plating adhesion refer to the sputter adhesion between the copper foil and the thermoplastic polyimide layer of the multilayer polyimide film when a copper foil is formed on the opposite side of one side of the thermoplastic polyimide layer in contact with the non-thermoplastic polyimide layer, and the thickness of the copper foil is 12 μm.

[0030] The above sputtering adhesion refers to the adhesion between a polyimide film (layer) and a metal foil (seed layer + plating layer) formed by sputtering on the upper surface of a polyimide film (layer) and plating a metal (such as copper) on the upper surface through electroplating. Since the thickness of the seed layer is at the level of several nanometers, it was assumed that it does not affect the adhesion and the thickness of the metal foil.

[0031] More specifically, the above room temperature plating adhesion refers to the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature (25℃±5℃), and the heat-resistant plating adhesion refers to the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature (25℃±5℃) after forming a seed layer by sputtering on the thermoplastic polyimide layer and then forming a copper foil on the seed layer through electroplating, and then heat-treating the multilayer polyimide film on which the copper foil is formed twice at 150℃ for 30 minutes and once at 240℃ for 10 minutes.

[0032] In one embodiment, the above plating adhesion strength can be measured by etching a multilayer polyimide film with a copper foil deposited thereon into a 2mm wide rod shape using a wet etching method, and then performing a 90° peel test with a Universal Testing Machine and pulling at a speed of 20mm / min.

[0033] To achieve the described plating adhesion, the present invention may apply a specific range of heat during the heat treatment of a thermoplastic polyimide layer. In one embodiment, the total amount of heat used for the heat treatment of the thermoplastic polyimide layer is 122 kcal / m² 2 Above, for example, 123 kcal / m²2 124 kcal / m² or more 2 It may be higher, 200 kcal / m² 2 Below, 190 kcal / m² 2 Below, 180 kcal / m² 2 170 kcal / m² or less 2 It may be less than.

[0034] For example, the total amount of heat used in the heat treatment of the thermoplastic polyimide layer is 122 to 200 kcal / m² 2 , 123 to 190 kcal / m² 2 , or 124 to 170 kcal / m² 2 It may be possible. If the total amount of heat used for the heat treatment of the thermoplastic polyimide layer is within the above range, the multilayer polyimide film may have the room temperature and heat-resistant plating adhesion required in the present invention.

[0035] When analyzing the XPS depth of the multilayer polyimide film of the present invention, the surface oxygen concentration of the thermoplastic polyimide layer may be 3% or more, 3.01% or more, 3.02% or more, or 3.04% or more, and may be 5.0% or less, 4.98% or less, 4.95% or less, or 4.93% or less, for example, 3.0% to 5.0%, 3.01% to 4.98%, or 3.04% to 4.93%.

[0036] The above surface oxygen concentration may be determined by checking the surface oxygen concentration when X-rays are incident on the surface of a sample for 30 seconds using XPS Depth of a multilayer polyimide film having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer laminated therein.

[0037] The oxygen concentration is attributed to functional groups on the surface of the thermoplastic polyimide film, and it may vary depending on the calorific conditions during the thermoplastic polyimide manufacturing process. X-ray photoelectron spectroscopy is an instrument that allows one to determine the composition and chemical bonding state of a sample surface by irradiating the surface with X-rays and measuring the energy of the emitted photoelectrons.

[0038] In addition, the contact angle of the thermoplastic polyimide layer of the multilayer polyimide film of the present invention may be 17° or more, 17.1° or more, 17.2° or more, or 17.3° or more. When the surface oxygen concentration and the contact angle are above the above ranges, the multilayer polyimide film may have the room temperature and heat-resistant plating adhesion required in the present invention.

[0039] In the present invention, the polyimide precursor may include an acid anhydride monomer and a diamine monomer, and the monomer used in the present invention includes the monomers described herein and their isomers.

[0040] The above non-thermoplastic polyimide layer comprises one or more acid dianhydride monomers selected from the group consisting of pyromellitic acid dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4-biphenyltetracarboxylic acid dianhydride (a-BPDA), oxydiphthalic acid anhydride (ODPA), bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), and combinations thereof; and

[0041] It may be formed from a non-thermoplastic polyimide precursor comprising one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline (4,4'-ODA), 3,4'-oxydianiline (3,4'-ODA), p-phenylenediamine (PPD), m-phenylenediamine (MPD), 4,4'-methylenedianiline (4,4'-MDA), 3,3'-methylenedianiline (3,3'-MDA), m-tolidine (m-tolidine) and combinations thereof.

[0042] In one embodiment, the non-thermoplastic polyimide layer may comprise an acid dianhydride monomer comprising 50 to 70 mol% of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) and 30 to 50 mol% of pyromellitic acid dianhydride (PMDA) based on 100 mol% of the total acid dianhydride monomer; and a diamine monomer comprising 60 to 80 mol% of p-phenylenediamine (PPD) and 20 to 40 mol% of m-tolydine based on 100 mol% of the total diamine monomer.

[0043] The lower limit of the content of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) included in the above non-thermoplastic polyimide layer may be 50 mol% or more, 51 mol% or more, 52 mol% or more, 53 mol% or more, 54 mol% or more, or 55 mol% or more based on 100 mol% of the total acid dianhydride monomer, and the upper limit may be 70 mol% or less, 65 mol% or less, 62 mol% or less, 60 mol% or less, or 58 mol% or less. For example, the content of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) may be 50 to 70 mol%, 52 to 65 mol%, or 54 to 60 mol% based on 100 mol% of the total acid dianhydride monomer.

[0044] The lower limit of the content of pyromellitic acid dianhydride (PMDA) included in the above non-thermoplastic polyimide layer may be 30 mol% or more, 32 mol% or more, 35 mol% or more, 40 mol% or more, or 42 mol% or more based on 100 mol% of the total acid dianhydride monomer, and the upper limit may be 50 mol% or less, 48 ​​mol% or less, 46 mol% or less, 45 mol% or less, or 44 mol% or less. For example, the content of pyromellitic acid dianhydride (PMDA) may be 30 to 50 mol%, 32 to 48 mol%, or 40 to 45 mol% based on 100 mol% of the total acid dianhydride monomer.

[0045] The lower limit of the content of p-phenylenediamine (PPD) included in the above non-thermoplastic polyimide layer may be 60 mol% or more, 62 mol% or more, 65 mol% or more, 66 mol% or more, or 68 mol% or more based on 100 mol% of the total diamine monomer, and the upper limit may be 80 mol% or less, 78 mol% or less, 76 mol% or less, 74 mol% or less, or 72 mol% or less. For example, the content of p-phenylenediamine (PPD) may be 60 to 80 mol%, 62 to 78 mol%, or 66 to 74 mol% based on 100 mol% of the total diamine monomer.

[0046] The lower limit of the content of m-tolydine included in the above non-thermoplastic polyimide layer may be 20 mol% or more, 22 mol% or more, 24 mol% or more, 26 mol% or more, or 28 mol% or more based on 100 mol% of the total diamine monomer, and the upper limit may be 40 mol% or less, 38 mol% or less, 36 mol% or less, 34 mol% or less, or 32 mol% or less. For example, the content of m-tolydine may be 20 to 40 mol%, 22 to 38 mol%, or 26 to 34 mol% based on 100 mol% of the total diamine monomer.

[0047] When the content of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), pyromellitic acid dianhydride (PMDA), p-phenylenediamine (PPD), and m-tolydine included in the above non-thermoplastic polyimide layer is within the above range, the multilayer polyimide film can have excellent dielectric loss rate and mechanical properties.

[0048] The thermoplastic polyimide layer comprises a selected acid dianhydride monomer consisting of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4-biphenyltetracarboxylic acid dianhydride (a-BPDA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride) (BPADA), pyromellitic acid dianhydride (PMDA), and combinations thereof; and

[0049] It may be formed from a thermoplastic polyimide precursor comprising one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline (4,4'-ODA), 3,4'-oxydianiline (3,4'-ODA), 1,4-bis(4-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)benzene (APB), 1,4-bis(3-aminophenoxy)benzene (143BAPB), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-bis(3-aminophenoxy)biphenyl (43BAPOBP), 4,4'-(1,3-phenylenedioxy)dianiline (TPE-R), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and combinations thereof.

[0050] In one embodiment, the thermoplastic polyimide layer may comprise one or more acid dianhydride monomers selected from 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride), pyromellitic acid dianhydride, and combinations thereof; and one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline, 4,4'-(1,3-phenylenedioxy)dianiline (TPE-R), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and combinations thereof.

[0051]

[0052] According to another aspect of the present invention, a non-thermoplastic polyimide layer; and a thermoplastic polyimide layer coated on one or both sides of the non-thermoplastic polyimide layer; wherein the thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and when a copper foil is formed on the opposite side of one side of the thermoplastic polyimide layer in contact with the non-thermoplastic polyimide layer, the thickness of the copper foil is 12 μm, the room temperature plating adhesion strength is 0.8 kgf / cm or more, and the heat-resistant plating adhesion strength is 0.8 kgf / cm or more, as a multilayer polyimide film, wherein the room temperature plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature, and the heat-resistant plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film having the copper foil formed thereon at 150°C for 30 minutes twice and at 240°C for 10 minutes once. A multilayer polyimide film is provided, wherein the adhesion between polyimide layers is such that the multilayer polyimide film is manufactured by heat-treating the thermoplastic polyimide layer after the thermoplastic polyimide layer is formed on one or both sides of the non-thermoplastic polyimide layer.

[0053] The multilayer polyimide film of the present invention can be manufactured by heat-treating the thermoplastic polyimide layer after the thermoplastic polyimide layer is coated on one or both sides of the non-thermoplastic polyimide layer. After completing the coating of the thermoplastic polyimide layer through heat treatment, the multilayer polyimide film of the present invention having improved room temperature and heat-resistant plating adhesion compared to conventional films can be manufactured by additionally heat-treating the thermoplastic polyimide layer.

[0054]

[0055] Additionally, according to another aspect of the present invention, the method comprises the steps of: preparing a non-thermoplastic polyimide layer (1); and coating a thermoplastic polyimide layer with a thickness of 0.5 to 2.5 μm on one or both sides of the non-thermoplastic polyimide layer (2). A method for manufacturing a multilayer polyimide film is provided, comprising the step (3) of heat-treating the thermoplastic polyimide layer to produce a multilayer polyimide film, wherein when a copper foil is formed on the opposite side of one surface of the thermoplastic polyimide layer that is in contact with the non-thermoplastic polyimide layer, the thickness of the copper foil is 12 μm, the room temperature plating adhesion is 0.8 kgf / cm or more, and the heat-resistant plating adhesion is 0.8 kgf / cm or more, the room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and the heat-resistant plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film on which the copper foil is formed at 150°C for 30 minutes twice and at 240°C for 10 minutes once.

[0056] In step (1) above, a non-thermoplastic polyimide layer can be prepared. The non-thermoplastic polyimide layer can be formed from the aforementioned non-thermoplastic polyimide precursor, and the following polyimide precursor polymerization method can be used.

[0057] For example, (i) a method of polymerizing by adding the entire amount of diamine monomer into a solvent, and then adding a dianhydride monomer in substantially equimolarity with the diamine monomer;

[0058] (ii) A method of polymerizing by placing the entire amount of dianhydride monomer into a solvent, and then adding a diamine monomer in substantially equimolarity with the dianhydride monomer;

[0059] (iii) a method of polymerization in which some components of the diamine monomer are placed in a solvent, some components of the dianhydride monomer are mixed with the reaction components, the remaining diamine monomer is added, and subsequently the remaining dianhydride monomer is added so that the diamine monomer and the dianhydride monomer are substantially equimolar;

[0060] (iv) There is a method of polymerization in which a dianhydride monomer is placed in a solvent, some components of the diamine compound are mixed with the reaction components, another dianhydride monomer is added, and then the remaining diamine monomer is added so that the diamine monomer and the dianhydride monomer are substantially equimolar.

[0061] A polyimide precursor can be formed on a support and dried to produce a gel, and a polyimide layer can be prepared by curing the gel.

[0062] The step of curing the gel can be performed through a process of preparing a gel film by drying a polyimide precursor formed on the support at a temperature of 20 to 120°C for 5 to 60 minutes, increasing the temperature of the gel film to 30 to 500°C at a rate of 1 to 8°C / minute, heat-treating it at 450 to 500°C for 5 to 60 minutes, and cooling it to 20 to 120°C at a rate of 1 to 8°C / minute.

[0063] The step of curing the gel film can be performed at 30 to 500°C. For example, the step of curing the gel film can be performed at 30 to 400°C, 30 to 300°C, 30 to 200°C, 30 to 100°C, 100 to 500°C, 100 to 300°C, 200 to 500°C, or 400 to 500°C.

[0064] The above support may be, for example, an inorganic substrate, and examples of inorganic substrates include glass substrates and metal substrates. The inorganic substrate may be a substrate on which amorphous silicon (a-Si), an inter-poly dielectric layer (IPD), silicon nitride (SiNx), or silicon oxide (SiOx) is deposited. The glass substrate may be soda-lime glass, borosilicate glass, alkali-free glass, etc., but is not limited to these.

[0065] The total amount of heat used for the heat treatment of the thermoplastic polyimide layer in steps (2) and (3) is 122 kcal / m² 2 Above, for example, 123 kcal / m² 2 124 kcal / m² or more 2 It may be higher, 200 kcal / m² 2 Below, 190 kcal / m² 2 Below, 180 kcal / m² 2 170 kcal / m² or less 2 It may be less than or equal to. For example, the total amount of heat used for the heat treatment of the thermoplastic polyimide layer is 122 to 200 kcal / m². 2 , 123 to 190 kcal / m² 2 , or 124 to 170 kcal / m² 2 It may be possible. If the total amount of heat used for the heat treatment of the thermoplastic polyimide layer is within the above range, the multilayer polyimide film may have the room temperature and heat-resistant plating adhesion required in the present invention.

[0066] When XPS Depth analysis of a multilayer polyimide film produced by the method for producing a multilayer polyimide film of the present invention, the surface oxygen concentration of the thermoplastic polyimide layer may be 3% or more, 3.01% or more, 3.02% or more, or 3.04% or more, and may be 5.0% or less, 4.98% or less, 4.95% or less, or 4.93% or less, for example, 3.0% to 5.0%, 3.01% to 4.98%, or 3.04% to 4.93%.

[0067] In addition, the contact angle of the thermoplastic polyimide layer of the multilayer polyimide film of the present invention may be 17° or more, 17.1° or more, 17.2° or more, or 17.3° or more. When the surface oxygen concentration and the contact angle are above the above ranges, the multilayer polyimide film may have the room temperature and heat-resistant plating adhesion required in the present invention.

[0068]

[0069] The present invention will be described in more detail below with reference to examples. However, these are presented as preferred examples of the present invention and should not be interpreted in any way as limiting the present invention.

[0070]

[0071] [Example]

[0072]

[0073] 1. Preparation of a non-thermoplastic polyimide layer

[0074]

[0075] DMF was added to a 500 ml reactor equipped with a stirrer and nitrogen injection / discharge pipes while injecting nitrogen, and the reactor temperature was set to 25°C. Then, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) and pyromellitic acid dianhydride (PMDA) as acid dianhydride monomers, and p-phenylenediamine (PPD) and m-tolidine as diamine monomers were added in the order and mol% listed in Table 1 below, and it was confirmed that they were completely dissolved. (Reaction 1)

[0076] Subsequently, pyromellitic acid dianhydride (PMDA) was additionally added, and the reactor temperature was raised to 30°C under a nitrogen atmosphere while stirring was continued for 120 minutes to produce polyamic acid. (Reaction 2)

[0077] A polyimide precursor composition was prepared by adding a particulate polymer in an adjusted amount to the polyamic acid prepared in this way and stirring to disperse it, and adding a catalyst and a dehydrating agent in an adjusted amount. Then, the degassed polyimide precursor composition was coated onto a glass substrate using a spin coater. Subsequently, a gel film was prepared by drying at a temperature of 120°C for 30 minutes under a nitrogen atmosphere, the gel film was heated to 450°C at a rate of 2°C / min, heat-treated at 450°C for 60 minutes, and cooled to 30°C at a rate of 2°C / min to obtain a non-thermoplastic polyimide layer.

[0078] [Table 1]

[0079]

[0080] 2. Preparation and Heat Treatment of Multilayer Polyimide Films

[0081]

[0082] As shown in Table 2 below, a thermoplastic polyimide precursor containing 100 mol% of 4,4'-oxydianiline (ODA) and 100 mol% of 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride) (BPADA) as polymerization units was applied to one side of the manufactured non-thermoplastic polyimide layer, and a first heat treatment was performed to form a thermoplastic polyimide layer (thickness 1.5 μm). Comparative Examples 1 to 3, which did not perform a second (additional) heat treatment, and Examples 1 to 10, which performed a second (additional) heat treatment, were prepared.

[0083]

[0084] The amount of heat used for heat treatment, room temperature and heat-resistant plating adhesion, contact angle, dielectric loss rate, and XPS depth of the multilayer polyimide films of Comparative Examples 1 to 3 and Examples 1 to 10 were measured and listed in Table 2.

[0085] The total amount of heat used in the above first and second heat treatments was calculated as follows.

[0086] Heat output (kcal / m²) = Output (kW) × 860 (1kW = 860 kcal / h) / (Heater width (mm) * Film width (mm)) / 60 min

[0087]

[0088] [Table 2]

[0089]

[0090] The measurement method for room temperature and heat-resistant plating adhesion, contact angle, and XPS depth of the manufactured polyimide film is as follows.

[0091]

[0092] (1) Room temperature and heat-resistant plating adhesion

[0093] A seed layer was formed on the multilayer polyimide film of the above comparative example and example using a sputtering method, and a plating layer was formed on the upper part of the seed layer through electroplating to produce a multilayer polyimide film having a copper foil (seed layer + plating layer) with a thickness of 12 μm.

[0094] - Room temperature plating adhesion: At room temperature (25℃±5℃), the multilayer polyimide film on which the copper foil was formed was etched into a 2mm wide rod shape using a wet etching method, and then a 90° peel test was performed using a Universal Testing Machine to measure the adhesion between the copper foil and the thermoplastic polyimide layer by pulling at a speed of 20mm / min.

[0095] - Heat-resistant plating adhesion: After heat-treating the multilayer polyimide film with the copper foil formed thereon twice at 150°C for 30 minutes and once at 240°C for 10 minutes, the multilayer polyimide film was etched into a 2mm wide rod shape using a wet etching method at room temperature (25°C±5°C), and then a 90° peel test was performed using a Universal Testing Machine to measure the adhesion between the copper foil and the thermoplastic polyimide layer by pulling at a speed of 20mm / min.

[0096]

[0097] (2) Contact angle

[0098] The contact angle was measured using a contact angle measuring instrument from SEO, with benzyl alcohol as the measurement solvent.

[0099]

[0100] (3) XPS Depth

[0101] XPS Depth (X-ray Photoelectron Spectrocopy) was performed using the K-Alpha facility to analyze the concentration of surface elements (Oxygen) by etching the surface with X-rays for 30 seconds.

[0102]

[0103] As can be seen from Table 2, the room temperature and heat-resistant plating adhesion strength of the multilayer polyimide film of the present invention is 0.8 kgf / cm or more. Since excellent plating adhesion strength can be secured even in very thin thicknesses and in room temperature and high temperature environments, it was confirmed that the occurrence of critical product defects such as short circuits in circuit wiring can be reduced and high-frequency high-speed communication can be realized.

[0104]

[0105] From the foregoing description, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. In this regard, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention should be interpreted as including all modifications or variations derived from the meaning and scope of the claims set forth below and their equivalents, rather than from the detailed description above.

Claims

1. Non-thermoplastic polyimide layer; and A multilayer polyimide film comprising a thermoplastic polyimide layer coated on one or both sides of the above-mentioned non-thermoplastic polyimide layer, The thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and When forming a copper foil on the opposite side of one surface of the thermoplastic polyimide layer that is in contact with the above-mentioned non-thermoplastic polyimide layer, At a thickness of 12㎛ of the copper foil, the room temperature plating adhesion is 0.8 kgf / cm or more, and the heat-resistant plating adhesion is 0.8 kgf / cm or more, and The above room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and The above heat-resistant plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film having the copper foil formed thereon at 150°C for 30 minutes twice and at 240°C for 10 minutes once. Multilayer polyimide film.

2. In Paragraph 1, The above non-thermoplastic polyimide layer is, One or more acid dianhydride monomers selected from the group consisting of pyromellitic acid dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4-biphenyltetracarboxylic acid dianhydride (a-BPDA), oxydiphthalic acid anhydride (ODPA), bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), and combinations thereof; and Formed from a non-thermoplastic polyimide precursor comprising one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline (4,4'-ODA), 3,4'-oxydianiline (3,4'-ODA), p-phenylenediamine (PPD), m-phenylenediamine (MPD), 4,4'-methylenedianiline (4,4'-MDA), 3,3'-methylenedianiline (3,3'-MDA), m-tolidine, and combinations thereof. Multilayer polyimide film.

3. In Paragraph 1, The above thermoplastic polyimide layer is, One or more acid anhydride monomers selected from the group consisting of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4-biphenyltetracarboxylic acid dianhydride (a-BPDA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride) (BPADA), pyromellitic acid dianhydride (PMDA), and combinations thereof; and Formed from a thermoplastic polyimide precursor comprising one or more diamine monomers selected from the group consisting of 4,4'-oxydianiline (4,4'-ODA), 3,4'-oxydianiline (3,4'-ODA), 1,4-bis(4-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)benzene (APB), 1,4-bis(3-aminophenoxy)benzene (143BAPB), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 4,4'-bis(3-aminophenoxy)biphenyl (43BAPOBP), 4,4'-(1,3-phenylenedioxy)dianiline (TPE-R), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and combinations thereof. Multilayer polyimide film.

4. In Paragraph 1, The above non-thermoplastic polyimide layer is, An acid dianhydride monomer comprising 50 to 70 mol% of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) and 30 to 50 mol% of pyromellitic acid dianhydride (PMDA), based on 100 mol% of the total acid dianhydride monomer; and A diamine monomer comprising 60 to 80 mol% of p-phenylenediamine (PPD) and 20 to 40 mol% of m-tolydine based on 100 mol% of the total diamine monomer; Multilayer polyimide film.

5. In Paragraph 3, The above thermoplastic polyimide layer is, One or more acid anhydride monomers selected from the group consisting of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride), pyromellitic acid dianhydride, and combinations thereof; and One or more diamine monomers selected from the group consisting of 4,4'-oxydianiline, 4,4'-(1,3-phenylenedioxy)dianiline (TPE-R), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and combinations thereof; comprising Multilayer polyimide film.

6. In Paragraph 1, A multilayer polyimide film having a surface oxygen concentration of 3.0% to 5.0% in the thermoplastic polyimide layer upon XPS depth analysis.

7. In Paragraph 1, A multilayer polyimide film having a contact angle of 17° or greater in a thermoplastic polyimide layer.

8. Non-thermoplastic polyimide layer; and A thermoplastic polyimide layer coated on one or both sides of the above-mentioned non-thermoplastic polyimide layer; comprising The thickness of the thermoplastic polyimide layer is 0.5 to 2.5 μm, and When forming a copper foil on the opposite side of one surface of the thermoplastic polyimide layer that is in contact with the above-mentioned non-thermoplastic polyimide layer, A multilayer polyimide film having a copper foil thickness of 12㎛, a room temperature plating adhesion strength of 0.8 kgf / cm or more, and a heat-resistant plating adhesion strength of 0.8 kgf / cm or more, wherein The above room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and The above heat-resistant plating adhesion strength is the adhesion strength between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film on which the copper foil is formed at 150°C for 30 minutes twice and at 240°C for 10 minutes once. The above multilayer polyimide film is manufactured by heat-treating the thermoplastic polyimide layer after the thermoplastic polyimide layer is formed on one or both sides of the non-thermoplastic polyimide layer. Multilayer polyimide film.

9. In Paragraph 8, The total amount of heat used for the heat treatment of the thermoplastic polyimide layer is 122 kcal / m² 2 Lee Sang-in, Multilayer polyimide film.

10. Step of preparing a non-thermoplastic polyimide layer (1); Step (2) of coating a thermoplastic polyimide layer with a thickness of 0.5 to 2.5 μm on one or both sides of a non-thermoplastic polyimide layer; and The method includes the step (3) of heat-treating the thermoplastic polyimide layer to produce a multilayer polyimide film, and When forming a copper foil on the opposite side of one surface of the thermoplastic polyimide layer that is in contact with the above-mentioned non-thermoplastic polyimide layer, At a thickness of 12㎛ of the copper foil, the room temperature plating adhesion is 0.8 kgf / cm or more, and the heat-resistant plating adhesion is 0.8 kgf / cm or more, and The above room temperature plating adhesion is the adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature, and The above heat-resistant plating adhesion is the plating adhesion between the copper foil and the thermoplastic polyimide layer measured at room temperature after heat-treating the multilayer polyimide film having the copper foil formed thereon at 150°C for 30 minutes twice and at 240°C for 10 minutes once. Method for manufacturing a multilayer polyimide film.

11. In Paragraph 10, The total amount of heat used for the heat treatment of the thermoplastic polyimide layer in steps (2) and (3) is 122 kcal / m² 2 Lee Sang-in, Method for manufacturing a multilayer polyimide film.

12. In Paragraph 10, A method for manufacturing a multilayer polyimide film in which, when XPS Depth analysis is performed on the multilayer polyimide film obtained in step (3), the surface oxygen concentration of the thermoplastic polyimide layer is 3.0% to 5.0%.

13. In Paragraph 10, A multilayer polyimide film obtained in step (3), wherein the contact angle of the thermoplastic polyimide layer of the multilayer polyimide film is 17° or greater.

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