KR20230081914A - Low dielectric polyimide film with improved adhesive and manufacturing method thereof - Google Patents

Abstract

The present invention provides a polyimide film and a method for manufacturing the polyimide film, which obtained by imidizing a polyamic acid solution containing a dianhydride component containing at least one selected from the group consisting of benzophenone tetracarboxylic dianhydride (BTDA), biphenyl tetracarboxylic dianhydride (BPDA), and pyromellitic dianhydride (PMDA), and a diamine component containing at least one selected from the group consisting of m-tolidine and paraphenylene diamine (PPD), wherein dielectric loss factor (Df) is 0.004 or less, surface roughness (Ra) is 0.1 nm to 3.0 nm, and surface roughness (Rz) is 3.0 nm to 20 nm. The polyimide film has low dielectric properties, low hygroscopicity, and high heat resistance, and has excellent adhesion to copper foil. In addition, it can be usefully applied to electronic components such as thin circuit boards capable of high-speed communication and flexible metal clad laminates that require such characteristics.

Description

Low dielectric polyimide film with improved adhesion and method for manufacturing the same

The present invention relates to a low dielectric polyimide film with improved adhesion and a manufacturing method thereof.

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

In particular, it is in the spotlight as a high-functional polymer material in the fields of electricity, electronics, and optics due to its excellent insulating properties, that is, excellent electrical properties such as low permittivity.

BACKGROUND ART [0002] In recent years, as electronic products have been reduced in weight and size, highly integrated and flexible thin circuit boards have been actively developed.

Such a thin circuit board tends to use a structure in which a circuit including a metal foil is formed on a polyimide film that has excellent heat resistance, low temperature resistance, and insulation characteristics and is easily bent.

As such a thin circuit board, a flexible metal clad laminate is mainly used, and as an example, a flexible copper clad laminate (FCCL) using a thin copper plate as a metal foil is included. In addition, polyimide is also used as a protective film or insulating film for thin circuit boards.

On the other hand, as various functions are inherent in recent electronic devices, fast calculation and communication speeds are required for the electronic devices, and to meet these demands, thin circuit boards capable of high-speed communication at high frequencies are being developed. In order to realize high-frequency high-speed communication, an insulator having high impedance capable of maintaining electrical insulation even at high frequencies is required. Since impedance is in inverse proportion to the frequency and dielectric constant (Dk) formed in the insulator, the dielectric constant must be as low as possible to maintain insulation even at high frequencies.

However, in the case of normal polyimide, dielectric properties are not at a level that is excellent enough to maintain sufficient insulation in high frequency communication.

In addition, it is known that as an insulator has a low dielectric characteristic, generation of undesirable stray capacitance and noise can be reduced in a thin circuit board, and thus, the causes of communication delay can be largely eliminated. Therefore, polyimide with low dielectric properties is recognized as the most important factor in the performance of thin circuit boards.

In particular, in the case of high-frequency communication, dielectric dissipation inevitably occurs through polyimide. Dielectric dissipation factor (Df) means the amount of electrical energy wasted on a thin circuit board and is closely related to the signal propagation delay that determines the communication speed. It is recognized as an important factor in the performance of the substrate.

Accordingly, conventionally, polyimides having low dielectric properties have been implemented through the application of fluorine-based and polyolefin-based monomers, but their adhesion to copper foil is significantly lower than existing products.

In order to solve this problem, the development of a polyimide material having improved adhesion to copper foil while having dielectric properties (Df) and thermal properties suitable for application of high-speed transmission materials is required.

Therefore, in order to solve the above problems, an object is to provide a polyimide film having excellent adhesion and low dielectric properties and a manufacturing method thereof.

An object of the present invention is to include at least one selected from the group consisting of benzophenonetetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) It is obtained by imidizing a polyamic acid solution containing a dianhydride component and a diamine component including at least one selected from the group consisting of m-tolidine and paraphenylene diamine (PPD), and dielectric loss rate (Df) is 0.004 or less, surface roughness (Ra) is 0.1 nm to 3.0 nm, surface roughness (Rz) is to provide a polyimide film of 3.0 nm to 20 nm.

Another object of the present invention is to provide a method for manufacturing the polyimide film.

Another object of the present invention is to provide a multilayer film including the polyimide film and a thermoplastic resin layer.

Another object of the present invention is to provide a flexible metal clad laminate comprising the polyimide film and the electrically conductive metal foil.

Another object of the present invention is to provide an electronic component including the flexible metal clad laminate.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

When amounts, concentrations, or other values or parameters herein are given as ranges, preferred ranges, or recitations of upper preferred and lower preferred values, any pair of any upper range limits, whether or not the ranges are separately disclosed, or It should be understood as specifically disclosing the preferred values and any lower range limits or all ranges formed from preferred values.

Where ranges of numerical values are recited herein, unless otherwise stated, it is intended that the ranges end points and the scope of the parent invention within the range are not limited to the specific values recited when defining the range.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, they should not be interpreted in an ideal or excessively formal meaning. don't

As used herein, “dianhydride acid” is intended to include its precursors or derivatives, which technically may not be dianhydride acids, but will nonetheless react with diamines to form polyamic acids, which in turn polyamic acids. can be converted to mid.

As used herein, "diamine" is intended to include precursors or derivatives thereof, which may not technically be diamines, but will nonetheless react with dianhydrides to form polyamic acids, which in turn will form polyamic acids. can be converted to mid.

Specific details for the implementation of the invention will be described below.

Low dielectric polyimide film with improved adhesion of the present invention

The present invention relates to a dianhydride containing at least one selected from the group consisting of benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA). It is obtained by imidizing a polyamic acid solution containing a component and a diamine component including at least one selected from the group consisting of m-tolidine and paraphenylene diamine (PPD), and the dielectric loss factor (Df ) is 0.004 or less, surface roughness (Ra) is 0.1 nm to 3.0 nm, and surface roughness (Rz) is 3.0 nm to 20 nm.

The "dielectric loss factor" of the present invention means a force dissipated by a dielectric (or insulator) when friction between molecules hinders molecular motion caused by an alternating electric field. The value of dielectric loss factor is commonly used as an index indicating the ease of dissipation of charge (dielectric loss). The higher the dielectric loss factor, the easier it is to dissipate charge. there is. That is, since the dielectric loss factor is a measure of power loss, the lower the dielectric loss factor, the faster the communication speed can be maintained while reducing the signal transmission delay caused by the power loss.

In one embodiment, the dielectric loss factor (Df) of the polyimide film may be preferably 0.0039 or less, 0.0038 or less, 0.0036 or less, 0.0035 or less, 0.0034 or less, or 0.0033 or less.

The "surface roughness" of the present invention is also referred to as surface roughness, and refers to fine curves appearing at small intervals on the surface. Surface roughness is a parameter representing center line average roughness (Ra) and 10-point average roughness (Rz). In general, the center line average roughness (Ra) in the field is calculated by calculating the average value of the deviation of all peaks and valleys that deviate from the average line over the entire reference length in the roughness curve, that is, assuming that the reference length (center average line) is flat without roughness. Measure the average height of the 10-point average roughness (Rz) by drawing a straight line parallel to the average line of the cross section and measuring the distance between the 5th highest peak and the 5th valley from the lowest to the lowest, showing the average difference, The above two parameters are representative parameters representing surface roughness. In general, as the value of the surface roughness parameter increases, the roughness of the surface increases. defined. In general, it can be interpreted that the higher the surface roughness (Ra, Rz) value, the greater the degree of roughness of the surface.

In one embodiment, the surface roughness (Ra) of the polyimide film of the present invention preferably has a lower limit of 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, 0.9 nm or more, 1.1 nm or more, 1.2 nm or more, or 1.3 nm or more. , 1.4 nm or more, 1.5 nm or more, or 1.6 nm or more, and the upper limit may be 2.5 nm or less, 2.0 nm or less, 1.8 nm or less, 1.7 nm or less, 1.6 nm or less, or 1.5 nm or less.

In one embodiment, the surface roughness (Rz) of the polyimide film of the present invention preferably has a lower limit of 3.5 nm or more, 4.0 nm or more, 4.5 nm or more, 5.0 nm or more, 7.0 nm or more, 8.0 nm or more, or 9.0 nm or more. , 10 nm or more, 11 nm or more, 12 nm or more, 13 nm or more or 14 nm or more, preferably the upper limit is 18 nm or less, 17 nm or less, 16 nm or less, 15 nm or less, 13 nm or less, 12 nm or less or 11 nm or less.

In the present invention, when the surface roughness (Ra) of the polyimide film is less than 0.1 nm and/or the surface roughness (Rz) is less than 3.0 nm, the surface roughness is low, resulting in poor adhesion to the copper foil, and the surface roughness ( When Ra) exceeds 3.0 nm and/or surface roughness (Rz) exceeds 20 nm, the adhesive strength of the film is not affected and rather the adhesive strength tends to decrease.

In the present invention, the polyimide film may be surface treated by photonic curing.

In the present invention, the surface treatment may cause a change in morphology and surface roughness of the polyimide film to affect adhesive properties.

Photonic curing is annealing thin films and materials using light from a flash lamp. Since the light exposure time is very short (generally less than 1 ms), the temperature of the substrate itself is relatively low while the film placed on the substrate is heated. maintain. That is, it is possible to apply a considerably high temperature to a thin film such as a polyimide film without damaging the plate through short pulse irradiation.

The photonic curing may be performed by a light pulse using a XENON flash lamp, and in an embodiment, a light pulse may be irradiated using a high XENON lamp.

In the present invention, the surface roughness of the polyimide treated by photonic curing is increased compared to the polyimide not subjected to photonic curing, thereby improving adhesion to the copper foil.

In one embodiment, the photonic curing is performed by light pulses having a wavelength of 100 to 800 nm, a light pulse irradiation time of 200 to 1,000 microseconds (μs), and a light energy of 0.5 to 5.0 J/cm ² . can

Preferably, the photonic curing may be performed by a light pulse having a wavelength of 100 to 800 nm, a light pulse irradiation time of 300 to 800 microseconds (μs), and a light energy of 0.7 to 3.0 J/cm ² . . More preferably, a light pulse having a wavelength of 200 to 400 nm, a light pulse irradiation time of 300 to 700 microseconds (μs), and a light energy of 1.0 to 2.6 J/cm ² may be irradiated.

In the present invention, the photonic curing light pulse may have an ultraviolet wavelength of 100 to 400 nm and a visible light wavelength of 400 to 800 nm, preferably 100 to 400 nm, more preferably 200 to 400 nm It may be an ultraviolet wavelength of

In one embodiment, the light pulse may be irradiated at an applied voltage in the range of 250 to 650 V, preferably an applied voltage in the range of 350 to 450 V, more preferably an applied voltage in the range of 380 to 420 V, most Preferably, it may be an applied voltage of 400 V.

In the present invention, the temperature of the photonic curing may be in the range of 200 to 700 °C, preferably 300 to 600 °C, and most preferably 400 to 600 °C.

In one embodiment, the intensity of the light pulse in the photonic curing is 2 to 6 kW/cm ² , preferably 3 to 5 kW/cm ² , more preferably 3.5 to 4.5 kW/cm ² . It may be, and most preferably 4 kW / cm ² It may be.

In one embodiment, the polyimide may have a thickness ranging from 35 to 45 um, preferably from 37 to 42 um, and more preferably from 37 to 40 um.

In the present invention, the polyamic acid film is a first block obtained by imidizing a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including paraphenylene diamine (PPD). ; And an agent obtained by imidization of a dianhydride component including benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine. 2 blocks; and the content of m-tolidine is 15 mol% or more and 45 mol% or less based on 100 mol% of the total content of the diamine component of the first block and the second block. , the content of paraphenylene diamine is 55 mol% or more and 85 mol% or less, particularly preferably the content of m-tolidine is 20 mol% or more and 40 mol% or less, and the content of paraphenylene diamine is 60 mol% It may be more than 80 mol% or less.

The content of benzophenonetetracarboxylic dianhydride is 20 mol% or more and 55 mol% or less based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxylic dianhydride The hydride content may be 25 mol% or more and 55 mol% or less, and the pyromellitic dianhydride content may be 15 mol% or more and 30 mol% or less. In particular, preferably, the content of the benzophenonetetracarboxylic dianhydride is 25 mol% or more and 50 mol% or less, and the content of biphenyltetracarboxylic dianhydride is 30 mol% or more and 50 mol% or less. The content of pyromellitic dianhydride may be 20 mol% or more and 27 mol% or less.

In one embodiment, the dianhydride component may additionally include pyromellitic dianhydride.

In addition, in the present invention, the polyamic acid film is a dianhydride component including benzophenonetetracarboxylic dianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and paraphenylene diamine (PPD) A first block obtained by imidization of a diamine component containing; And a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine (m-tolidine) obtained by imidization reaction A block copolymer comprising a second block, wherein the content of m-tolidine is 20 mol% or more and 35 mol% or less based on 100 mol% of the total content of the diamine component of the first block and the second block And, the content of paraphenylene diamine is 65 mol% or more and 80 mol% or less. In particular, the content of m-tolidine is preferably 20 mol% or more and 30 mol% or less.

The content of benzophenonetetracarboxylic dianhydride is 10 mol% or more and 20 mol% or less based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxylic dian The hydride content may be 40 mol% or more and 60 mol% or less, and the pyromellitic dianhydride content may be 20 mol% or more and 45 mol% or less. Preferably, the content of the benzophenone tetracarboxylic dianhydride may be 15 mol% or more and 20 mol% or less.

In one embodiment, the dianhydride component may additionally include pyromellitic dianhydride.

In addition, in the present invention, the polyamic acid film is a dianhydride component including benzophenonetetracarboxylic dianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and paraphenylene diamine (PPD) A first block obtained by imidization of a diamine component containing; And a second block obtained by the imidization reaction of a dianhydride component containing pyromellitic dianhydride (PMDA) and a diamine component containing m-tolidine. , Based on 100 mol% of the total content of the dianhydride component, the content of the benzophenone tetracarboxylic dianhydride is 10 mol% or more and 40 mol% or less, and the content of the biphenyltetracarboxylic dianhydride is 30 mol% or more and 80 mol% or less, the content of m-tolidine is 20 mol% or more and 40 mol% or less based on 100 mol% of the total content of the diamine component, and the paraphenylene diamine content is 60 mol% It may be more than 80 mol% or less. Preferably, the content of m-tolidine may be 30 mol% or more and 40 mol% or less.

Also, preferably, the content of the benzophenonetetracarboxylic dianhydride is 10 mol% or more and 40 mol% or less based on 100 mol% of the total content of the dianhydride component, and the biphenyltetracarboxylic dianhydride The content of may be 30 mol% or more and 80 mol% or less. In particular, it is preferable that the content of the benzophenonetetracarboxylic dianhydride is 15 mol% or more and 35 mol% or less, and the content of the biphenyltetracarboxylic dianhydride is 35 mol% or more and 75 mol% or less. Also, preferably, the content of the pyromellitic dianhydride may be 50 mol% or less based on 100 mol% of the total content of the dianhydride component, or may not be included at all.

In one embodiment, pyromellitic dianhydride may be additionally included as the dianhydride component.

In one embodiment, the polyimide film of the present invention may have a coefficient of thermal expansion (CTE) of 19 ppm/°C or less, and a glass transition temperature (Tg) of 400°C.

In this regard, in the case of a polyimide film that satisfies all of the dielectric loss factor (Df), glass transition temperature, and thermal expansion coefficient, it can be used as an insulating film for flexible metal-clad laminates, and the manufactured flexible metal-clad laminates can generate high-frequency signals of 10 GHz or more. Even if it is used as an electrical signal transmission circuit that transmits, its insulation stability can be secured and signal transmission delay can be minimized.

Manufacturing method of low dielectric polyimide film with improved adhesiveness of the present invention

The present invention includes (a) at least one selected from the group consisting of benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) After forming a polyamic acid solution containing a diamine component including a dianhydride component and a diamine component including at least one selected from the group consisting of m-tolidine and paraphenylene diamine (PPD) on a support, an imidation reaction To prepare a polyamic acid film; and (b) preparing a surface-treated polyimide film through a photonic curing process by irradiating the polyamic acid film with light pulses; Including, wherein the polyimide film has a dielectric loss factor (Df) of 0.004 or less, a surface roughness (Ra) of 0.1 nm to 3.0 nm, and a surface roughness (Rz) of 3.0 nm to 20 nm, manufacturing a polyimide film provides a way

In one embodiment, the polymerization method of the polyamic acid solution in step (a) may be defined as a random polymerization method.

Preparation of the polyamic acid solution of the present invention, for example,

(1) A method in which the entire amount of the diamine component is placed in a solvent, and thereafter a dianhydride component is added so as to be substantially equimolar to the diamine component, followed by polymerization;

(2) a method in which the entire amount of the dianhydride component is placed in a solvent, and then a diamine component is added so as to be substantially equimolar to the dianhydride component, followed by polymerization;

(3) After putting some of the diamine components in a solvent, mixing some of the dianhydride components at a ratio of 95 to 105 mol% with respect to the reaction components, and then adding the remaining diamine components, followed by the remaining dianhydride components. A method of polymerizing by adding a diamine component and a dianhydride component so that they are substantially equimolar;

(4) After putting the dianhydride component in the solvent, some components of the diamine compound are mixed in a ratio of 95 to 105 mol% with respect to the reaction components, then another dianhydride component is added, and then the remaining diamine components are added, a method of polymerizing the diamine component and the dianhydride component so that they are substantially equimolar;

(5) Some diamine components and some dianhydride components are reacted in an excess amount in a solvent to form a first composition, and some diamine components and some dianhydride components in another solvent are reacted in an excess amount to form a first composition. A method of mixing the first and second compositions after forming two compositions and completing the polymerization. At this time, if the diamine component is excessive when forming the first composition, the second composition contains an excess of the dianhydride component And, when the dianhydride component is excessive in the first composition, the diamine component is excessive in the second composition, and the first and second compositions are mixed so that the entire diamine component and the dianhydride component used in these reactions are substantially equal. The method of polymerizing by making it mole, etc. are mentioned.

In one specific example, the method for producing a polyimide film according to the present invention,

(a) preparing a first polyamic acid by polymerizing a first dianhydride component and a first diamine component in an organic solvent;

(b) preparing a second polyamic acid by polymerizing the second dianhydride component and the second diamine component in an organic solvent;

(c) preparing a third polyamic acid by copolymerizing the first polyamic acid and the second polyamic acid in an organic solvent; and

(d) forming a precursor composition containing the third polyamic acid on a support, followed by imidization;

The first dianhydride component and the second dianhydride component are composed of benzophenonetetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA), respectively. The first diamine component and the second diamine component may each contain at least one selected from the group consisting of m-tolidine and para-phenylene diamine (PPD). can

The content and composition of each component in the manufacturing method of the polyimide film are as described above for the polyimide film of the present invention.

In one embodiment, the first dianhydride component comprises biphenyltetracarboxylic dianhydride (BPDA) and the second dianhydride component comprises benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic It may include dianhydride (PMDA), the first diamine component may include paraphenylene diamine (PPD), and the second diamine component may include m-tolidine. In addition, based on 100 mol% of the total content of the first diamine component and the second diamine component, the content of m-tolidine is 15 mol% or more and 45 mol% or less, and the content of paraphenylene diamine is 55 mol% or more 85 mol% or less. In addition, the content of benzophenone tetracarboxylic dianhydride is 20 mol% or more and 55 mol% or less based on 100 mol% of the total content of the first dianhydride acid and the second dianhydride component, and biphenyltetracarboxylic The content of dianhydride may be 25 mol% or more and 55 mol% or less, and the content of pyromellitic dianhydride may be 15 mol% or more and 30 mol% or less.

In another embodiment, the first dianhydride component includes benzophenonetetracarboxylic dianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA), and the second dianhydride component includes biphenyl It includes tetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride, the first diamine component includes paraphenylene diamine (PPD), and the second diamine component includes m-tolidine (m- tolidine). The content of m-tolidine is 20 mol% or more and 35 mol% or less, and the content of paraphenylene diamine is 65 mol% or more 80 mol% based on 100 mol% of the total content of the first diamine component and the second diamine component. % or less. In addition, the content of benzophenone tetracarboxylic dianhydride is 10 mol% or more and 20 mol% or less based on 100 mol% of the total content of the first dianhydride acid and the second dianhydride component, and biphenyltetracarboxylic The content of dianhydride may be 40 mol% or more and 60 mol% or less, and the content of pyromellitic dianhydride may be 20 mol% or more and 45 mol% or less.

In another embodiment, the first polyamic acid is a first dianhydride component including benzophenonetetracarboxylic dianhydride and biphenyltetracarboxylic dianhydride and a first diamine including paraphenylene diamine component, and the second polyamic acid may include a second dianhydride component including pyromellitic dianhydride and a second diamine component including m-tolidine. The first diamine component and the second diamine component are characterized in that they include at least one selected from the group consisting of m-tolidine and para-phenylene diamine (PPD). Based on 100 mol% of the total content of the first diamine component and the second diamine component, the content of m-tolidine is 20 mol% or more and 40 mol% or less, and the content of paraphenylene diamine is 60 mol% or more 80 mol% mol% or less, and the content of the benzophenonetetracarboxylic dianhydride is 10 mol% or more and 40 mol% or less based on 100 mol% of the total content of the first dianhydride component and the second dianhydride component, and the ratio The content of phenyltetracarboxylic dianhydride may be 30 mol% or more and 80 mol% or less.

In addition, the organic solvent for synthesizing the polyamic acid is not particularly limited, and any organic solvent can be used as long as it dissolves the polyamic acid, but an amide solvent is preferable. Specifically, the organic solvent may be an organic polar solvent, and in detail, may be an aprotic polar solvent, for example, N,N-dimethylformamide (DMF), N,N -It may be one or more selected from the group consisting of dimethylacetamide, N-methyl-pyrrolidone (NMP), gamma butyrolactone (GBL), and diglyme, but is not limited thereto, and may be used alone as needed Or it can use in combination of 2 or more types.

In one embodiment, N,N-dimethylformamide and N,N-dimethylacetamide may be particularly preferably used as the solvent.

Since the polymerization method produces a relatively short length of the repeating unit in the polymer chain described above, there may be limitations in exhibiting the excellent characteristics of each polyimide chain derived from the dianhydride component. Therefore, the polymerization method of the polyamic acid that can be particularly preferably used in the present invention may be a block polymerization method.

In one embodiment of the present invention, photonic curing in step (b) may be to irradiate at an applied voltage in the range of 250 to 650 V, preferably at an applied voltage in the range of 350 to 450 V, more preferably at 380 V. to 420 V, most preferably 400 V.

In one embodiment, the photonic curing is performed in the range of the above-described applied voltage, with a wavelength of 100 to 800 nm, a light pulse irradiation time of 200 to 1,000 microseconds (μs), and light of 0.5 to 5.0 J/cm ^{2 .} It may be by a light pulse irradiated under the condition of energy.

In one embodiment, the photonic curing is performed in the range of the above-described applied voltage, with a wavelength of 100 to 800 nm, a light pulse irradiation time of 300 to 800 microseconds (μs), and light of 0.5 to 3.0 J/cm ^{2 .} It may be by a light pulse irradiated under the condition of energy. Preferably, it may be by a light pulse irradiated under conditions of a wavelength of 200 to 400 nm, a light pulse irradiation time of 300 to 700 microseconds (μs), and light energy of 1.0 to 2.6 J/cm ² .

In the present invention, the photonic curing light pulse may have an ultraviolet wavelength of 100 to 400 nm and a visible light wavelength of 400 to 800 nm, preferably 100 to 400 nm, more preferably 200 to 400 nm It may be an ultraviolet wavelength.

In the present invention, the temperature of the photonic curing may be in the range of 200 to 700 °C, preferably 300 to 600 °C, and most preferably 400 to 600 °C.

As the photonic curing process is performed in the present invention, by irradiating the polyamic acid film with short pulses of UV light, it is possible to improve adhesion by causing a change in the morphology of the surface to maintain excellent dielectric properties and heat resistance properties.

The coefficient of thermal expansion (CTE), glass transition temperature, and moisture absorption of the polyimide film prepared according to the method for manufacturing the polyimide film of the present invention are as described above for the polyimide film of the present invention.

Multi-layer film, flexible metal laminate and electronic component containing the polyimide film of the present invention

The present invention provides a multilayer film comprising the above-described polyimide film and a thermoplastic resin layer, and a flexible metal-clad laminate comprising the above-described polyimide film and electrically conductive metal foil.

As the thermoplastic resin layer, for example, a thermoplastic polyimide resin layer may be applied.

The metal foil used is not particularly limited, but in the case of using the flexible metal clad laminate of the present invention for electronic devices or electrical devices, for example, copper or copper alloy, stainless steel or its alloy, nickel or nickel alloy (42 alloy) Also included), it may be a metal foil containing aluminum or aluminum alloy.

In general flexible metal clad laminates, copper foils such as rolled copper foil and electrolytic copper foil are often used, and they can be preferably used in the present invention as well. Moreover, a rust prevention layer, a heat resistance layer, or an adhesive layer may be applied to the surface of these metal foils.

In the present invention, the thickness of the metal foil is not particularly limited, and may be any thickness capable of exhibiting sufficient functions depending on its use.

In the flexible metal clad laminate according to the present invention, a metal foil is laminated on one surface of the polyimide film, or an adhesive layer containing thermoplastic polyimide is added to one surface of the polyimide film, and the metal foil is attached to the adhesive layer. It may be a laminated structure.

The present invention also provides an electronic component including the flexible metal clad laminate as an electrical signal transmission circuit. The electrical signal transmission circuit may be an electronic component that transmits a signal at a high frequency of at least 2 GHz, specifically at a high frequency of at least 5 GHz, and more specifically at a high frequency of at least 10 GHz.

The electronic component may be, for example, a communication circuit for a portable terminal, a communication circuit for a computer, or a communication circuit for aerospace, but is not limited thereto.

The polyimide film according to the present invention has low dielectric properties, low hygroscopicity and high heat resistance, and excellent adhesion to copper foil. In addition, it can be usefully applied to electronic components such as thin circuit boards and flexible metal clad laminates capable of high-speed communication devices requiring such characteristics.

1 is a schematic diagram of a manufacturing process of a polyimide film according to the present invention.
Figure 2 shows the AFM analysis results of the polyimide film according to the present invention.

Examples are presented to aid understanding of the present invention. The following examples are only provided to more easily understand the present invention, but the content of the present invention is not limited by the examples.

<Example 1> Preparation of polyamic acid film

Inject DMF while injecting nitrogen into a 500 ml reactor equipped with a stirrer and nitrogen inlet/discharge pipe, set the temperature of the reactor to 30 ° C or less, and then paraphenylene diamine (PPD) as a diamine component and biphenyl as a dianhydride component It is confirmed that at least one of tetracarboxylic dianhydride (BPDA) and benzophenone tetracarboxylic dianhydride (BTDA) is completely dissolved. After raising the temperature to 40 ° C. under a nitrogen atmosphere and continuing stirring for 120 minutes while heating, a first polyamic acid having a viscosity of 200,000 cP at 23 ° C. was prepared.

NMP was injected while nitrogen was injected into a 500 ml reactor equipped with a stirrer and nitrogen inlet/discharge pipe, and the temperature of the reactor was set to 30 ° C. m-tolidine as a diamine component and benzophenone tetracarboxylic dianhydride as a dianhydride component It is confirmed that at least one of fluoride and pyromellitic dianhydride is completely dissolved. After raising the temperature to 40 ° C. under a nitrogen atmosphere and continuing stirring for 120 minutes while heating, a second polyamic acid having a viscosity of 200,000 cP at 23 ° C. was prepared.

Then, after heating the first polyamic acid and the second polyamic acid to 40 ° C. under a nitrogen atmosphere, stirring was continued for 120 minutes, and the final viscosity at 23 ° C. was 200,000 cP, and the diamine component and the dianhydride component To prepare a third polyamic acid containing as shown in Table 1.

Air bubbles were removed from the third polyamic acid prepared above by high-speed rotation of 1,500 rpm or more. Thereafter, the degassed polyimide precursor composition was applied to the glass substrate using a spin coater. Thereafter, a gel film was prepared by drying under a nitrogen atmosphere at a temperature of 120° C. for 30 minutes, heating the gel film to 450° C. at a rate of 2° C./min, heat treatment at 450° C. for 60 minutes, and heating the gel film to 30° C. It was cooled at a rate of 2 °C/min to obtain a polyamic acid film.

Examples 1-1 to 1-12: Preparation of polyamic acid films

It was prepared according to <Example 1> described above, but the composition ratio of the dianhydride component and the diamine component was adjusted as shown in Table 1 below.

dianhydride component (mol%) Diamine component (mol%) polyamic acid
polymerization method BPDA
(mole%) BTDA
(mole%) PMDA
(mole%) m-Tolidine
(mole%) PPD
(mole%) Example 1-1 33 40 27 30 70 block polymerization Example 1-2 50 25 25 20 80 block polymerization Example 1-3 30 50 20 40 60 block polymerization Example 1-4 35 40 25 30 70 block polymerization Example 1-5 40 17 43 30 70 block polymerization Example 1-6 45 17 38 30 70 block polymerization Examples 1-7 55 17 28 30 70 block polymerization Examples 1-8 60 17 23 30 70 block polymerization Examples 1-9 75 25 - 30 70 block polymerization Examples 1-10 50 17 33 30 70 block polymerization Example 1-11 35 17 48 30 70 block polymerization Examples 1-12 35 32 33 30 70 block polymerization

<Example 2> Preparation of polyimide film

The polyamic acid film obtained in Example 1 was irradiated with light under the conditions shown in Table 2 below to perform a photonic curing process to obtain surface-treated polyimide films of Examples 2-1 to 2-3. The photonic curing process used Novacentrix's photonic curing equipment that irradiates UV light.

The thickness of the prepared polyimide film was 40±5 μm. The thickness was measured using Anritsu's electric film thickness tester.

Examples 2-1 to 2-3: Preparation of polyimide film

The polyimide films of Examples 2-1 to 2-3 were prepared by the method of <Example 2> described above, but under the conditions shown in Table 2 below for the light pulse irradiation time, intensity, light energy, and surface treatment temperature. manufactured.

applied voltage
(V) light pulse irradiation time
(duration) (μs) robbery
(kW/cm ² ) light energy
(J/cm ² ) temperature
(℃) thickness
(μm) Example 2-1 400 319 4.00 1.08 400 37.8 Example 2-2 400 463 4.00 1.72 500 38.9 Example 2-3 400 670 4.00 2.59 600 39.2

<Experimental example>

Experimental Example 1: Dielectric loss factor (Df) measurement

The dielectric loss factor (Df) of the polyimide films prepared according to Examples 2-1 to 2-3 was measured by a split post dielectric resonator (SPDR) method, and an ENA Vector Network Analyzer (E5063A, Keysight) model was used. and SPDR was used by QWED. In order to measure the dielectric properties, the polyimide films of Examples 2-1 to 2-3 were prepared in a size of 50 mm x 50 mm, respectively, and then dried at a temperature of 130° C. for 30 minutes to remove moisture. After aging for 24 hours in a constant temperature and humidity chamber set at 23° C./50% RH, the dielectric properties of the film sample aged for 24 hours were measured using an ENA device. The results are shown in Table 3 below.

Referring to Table 3, the dielectric loss factor (Df) of the polyimide films prepared according to Examples 2-1 to 2-3 of the present invention is 0.004 or less, indicating a remarkably low dielectric loss factor.

Dielectric loss factor (Df) Example 2-1 0.00344 Example 2-2 0.00332 Example 2-3 0.00328

Experimental Example 2: Morphology analysis using AFM (Atomic Force Microscopy)

Polyimide film before surface treatment using photonic curing (Ref) (a) and Example 2-1 (b), Example 2-2 (c), Example 2-3 (d) of the polyimide film Surface morphology was measured using an AFM device. The results are shown in Figure 2.

Experimental Example 3: Surface Roughness (Ra, Rz) Analysis

OP (Optical profiler, nanoview of Nanosystems) was used to measure the surface roughness of the polyimide film (Ref) before surface treatment using photonic curing and the polyimide film obtained in Examples 2-1 to 2-3 The surface roughness values Rz and Ra values were compared and measured. The results are shown in Table 4.

Referring to Table 4, it was found that a change occurred on the surface by surface treatment using photonic curing. At a temperature of 300℃ or higher, the roughness tended to increase continuously, which is correlated with the cause of change in adhesive force, which is one of the characteristics for FPCB substrates. The higher the surface roughness (roughness), the higher the adhesive force. can be formed

Ra Rz Ref 0.001 0.006 Example 2-1 1.223 10.816 Example 2-2 1.44 12.049 Example 2-3 1.67 14.750

Experimental Example 4: Analysis of adhesion of the polyimide film of the present invention to copper foil

In order to measure the adhesion of the polyimide film of the present invention to the copper foil, the surface of the polyimide (Ref) not subjected to surface treatment using photonic curing and the polyimide of Examples 2-1 to 2-3 After coating the adhesive layer, it was dried at 110°C to 350°C. After the sample was laminated, a laminate was prepared by laminating with Cu foil using a hot press (condition: 320 ° C temperature, 15 MPA, for 40 seconds). After cutting the sample into 100 mm x 100 mm with a rotating wheel, 90-degree peel method, the Cu foil and the film were separated and the Cu foil was pulled at 90 degrees to measure the adhesive strength. The results are shown in Table 5.

Feel Strength (g/cm) Ref 430 Example 2-1 524 Example 2-2 577 Example 2-3 603

Referring to Table 5, the adhesive strength of the films of Examples 2-1 to 2-3, which are polyimide films surface-treated by photonic curing, compared to the polyimide film (Ref) without photonic curing was found to be high. When the surface morphology analysis results of Experimental Example 2 and the surface roughness analysis results of Experimental Example 3 were combined, it was analyzed that the increase in surface roughness and the increase in adhesive strength between the polyimide film and the Cu foil were in a mutually proportional relationship.

Experimental Example 5: Thermal expansion coefficient and glass transition temperature measurement

For the coefficient of thermal expansion (CTE), TA's thermomechanical analyzer Q400 model was used, and the polyimide films of Examples 1-1 to 1-12 were cut into a width of 4 mm and a length of 20 mm, and then 0.05 N in a nitrogen atmosphere. While applying a tension of , the temperature was raised from room temperature to 300 ° C at a rate of 10 ° C / min, and then cooled again at a rate of 10 ° C / min to measure the slope of the 100 ° C to 200 ° C section. The results are shown in Table 6 below.

For the glass transition temperature (Tg), the loss modulus and storage modulus of each film were obtained using DMA, and the inflection point was measured as the glass transition temperature in the tangent graph. The results are shown in Table 6 below.

CTE
(ppm/℃) Tg
(℃) Example 1-1 18.8 335 Example 1-2 15.8 345 Example 1-3 15.7 338 Example 1-4 13.9 352 Example 1-5 8.3 310 Example 1-6 11.3 306 Examples 1-7 13.5 303 Examples 1-8 15.2 301 Examples 1-9 - 320 Examples 1-10 - 320 Example 1-11 - 368 Examples 1-12 - 350

In the specification, details that can be sufficiently recognized and inferred by those skilled in the art of the present invention are omitted, and the technical spirit or essential configuration of the present invention other than the specific examples described in the present specification is not changed. More diverse modifications are possible within a limited range. Therefore, the present invention may be practiced in a manner different from that specifically described and exemplified herein, which can be understood by those skilled in the art.

Claims (10)

A dianhydride component containing at least one selected from the group consisting of benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) and m -Obtained by imidization reaction of a polyamic acid solution containing a diamine component containing at least one selected from the group consisting of m-tolidine and paraphenylene diamine (PPD),
The dielectric loss factor (Df) is 0.004 or less,
The surface roughness (Ra) is 0.1 nm to 3.0 nm,
A polyimide film having a surface roughness (Rz) of 3.0 nm to 20 nm. According to claim 1,
The polyimide film,
The dielectric loss factor (Df) is 0.0035 or less,
The surface roughness (Ra) is 1.0 nm to 2.0 nm,
A polyimide film having a surface roughness (Rz) of 5.0 nm to 18 nm. According to claim 1,
The polyimide film,
Dielectric loss factor (Df) is 0.0034 or less,
The surface roughness (Ra) is 1.0 nm to 1.8 nm,
A polyimide film having a surface roughness (Rz) of 10.0 nm to 15 nm. The method of claim 1, wherein the polyimide film is surface-treated by photonic curing,
The photonic curing has a wavelength of 100 to 800 nm,
A light pulse irradiation time of 200 to 1,000 microseconds (μs), and
0.5 to 5.0 J / cm ² By the light pulse having a light energy of, a polyimide film. The method of claim 4, wherein the light pulse is irradiated at an applied voltage in the range of 250 to 650 V,
The temperature of the photonic curing is in the range of 200 to 700 ℃, the polyimide film. The first method of claim 1, wherein the polyamic acid film is obtained by imidizing a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including paraphenylene diamine (PPD). block; and
Second obtained by imidization of a dianhydride component including benzophenone tetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine Including a block copolymer comprising a block;
The content of m-tolidine is 15 mol% or more and 45 mol% or less, and the content of paraphenylene diamine is 55 mol% or more 85 less than mol%,
The content of benzophenonetetracarboxylic dianhydride is 20 mol% or more and 55 mol% or less based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxylic dianhydride A hydride content of 25 mol% or more and 55 mol% or less, and a pyromellitic dianhydride content of 15 mol% or more and 30 mol% or less, a polyamic acid film;
An agent obtained by imidization of a dianhydride component including benzophenonetetracarboxylic dianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including para-phenylene diamine (PPD) 1 block; and
An agent obtained by imidization of a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine. 2 block; including a block copolymer comprising,
Based on 100 mol% of the total content of the diamine components of the first block and the second block, the content of m-tolidine is 20 mol% or more and 35 mol% or less, and the content of paraphenylene diamine is 65 mol% or more 80 less than mol%,
The content of benzophenonetetracarboxylic dianhydride is 10 mol% or more and 20 mol% or less based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxylic dian A hydride content of 40 mol% or more and 60 mol% or less, and a pyromellitic dianhydride content of 20 mol% or more and 45 mol% or less, a polyamic acid film; and
An agent obtained by imidization of a dianhydride component including benzophenonetetracarboxylic dianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including para-phenylene diamine (PPD) 1 block; and
A second block obtained by imidization of a dianhydride component containing pyromellitic dianhydride (PMDA) and a diamine component containing m-tolidine; Including a block copolymer comprising,
The content of the benzophenonetetracarboxylic dianhydride is 10 mol% or more and 40 mol% or less based on 100 mol% of the total content of the dianhydride component, and the content of the biphenyltetracarboxylic dianhydride is 30 mol % or more and 80 mol% or less,
Based on 100 mol% of the total content of the diamine component, the content of the m-tolidine is 20 mol% or more and 40 mol% or less, and the content of the paraphenylene diamine is 60 mol% or more and 80 mol% or less, a polyamic acid film ; At least one selected from the polyimide film. The method of claim 1, wherein the coefficient of thermal expansion (CTE) is 19 ppm / ℃ or less,
The glass transition temperature (Tg) is 400 ℃ or more,
polyimide film. (a) dianhydride containing at least one selected from the group consisting of benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) A polyamic acid solution containing a component and a diamine component including at least one selected from the group consisting of mtolidine and paraphenylene diamine (PPD) is formed on a support, and then subjected to imidation reaction to polyamic acid. making a film; and
(b) preparing a surface-treated polyimide film through a photonic curing process by irradiating light pulses to the polyamic acid film; including,
The polyimide film,
The dielectric loss factor (Df) is 0.004 or less,
The surface roughness (Ra) is 0.1 nm to 3.0 nm,
A method for producing a polyimide film having a surface roughness (Rz) of 3.0 nm to 20 nm. The method of claim 8, wherein the photonic curing is performed at an applied voltage in the range of 250 to 650 V,
wavelengths from 100 to 800 nm;
Light pulse irradiation time of 200 to 1,000 microseconds (μs) and
0.5 to 5.0 J / cm ² By light pulses irradiated under conditions of light energy, a method for producing a polyimide film. A flexible metal clad laminate comprising the polyimide film according to claim 1 and the electrically conductive metal foil.

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