KR101440276B1 - Polyimide film for electronic device component - Google Patents

Abstract

The present invention relates to a polyimide film, and more particularly, to a polyimide film comprising a polyimide film comprising 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride An aromatic dianhydride component containing 30 to 100 mol% of water in the total acid dianhydride component and an aromatic diamine component containing 50 to 100 mol% of paraphenylenediamine in the total diamine component The polyimide film of the present invention derived from a polyamide acid resin has a tensile modulus of 4.5 to 9.0 GPa, a thermal expansion coefficient of 10 to 25 ppm / 占 폚, a moisture absorption rate of 2.0% or less, a moisture absorption coefficient of expansion of 20 ppm / Since the weight loss rate is 5% or less, it exhibits excellent metal bonding strength, bending resistance, rate of dimensional change after etching, and curl when applied to electronic equipment materials, and thus can be usefully used in the field of electronic devices.

Description

POLYIMIDE FILM FOR ELECTRONIC DEVICE COMPONENTS

The present invention relates to polyimide films useful for electronic component parts.

The polyimide film is excellent in heat resistance, chemical resistance, electrical insulation and mechanical dimensional stability. Particularly, the polyimide film is advantageously used in the field of electronic equipment parts, for example, a semiconductor insulating tape, a flexible printed circuit board (FPCB), insulation tape for tape automated bonding (TAB), and chip on film (COF).

In recent years, along with the breakthrough of circuit manufacturing technology and component mounting technology, the FPCB for COF is rapidly becoming finer. In order to cope with the development of the fine pitch packaging technology of COF, it is necessary to manufacture the FPCB circuit without short circuit. For this purpose, dimensional stability of heating and tensile force of the polyimide film as the insulating material is very important . In general, the dimensional stability for heating is improved as the coefficient of thermal expansion (CTE) is lower, and the dimensional stability for the tensile force is higher as the elastic modulus is higher. Conventionally, there is known a technique for producing a film using a monomer having a high linearity and a rigid structure such as pyromellitic dianhydride or para-phenylenediamine as a method of producing a film having a low thermal expansion coefficient and a high elastic modulus. However, the above technology can achieve an extremely low coefficient of thermal expansion and a high elastic modulus because it is composed of only a rigid raw material, but the flexibility of the film is insufficient to satisfy the flexural properties required in the flexible circuit board, and pyromellitic acid dyes There is a problem that the moisture absorption rate of the final polyimide film rises when only monomers having high electron affinity such as water are used.

In addition, unlike other polymer materials, polyimide has a somewhat higher moisture absorption rate, and accordingly, there is an increasing demand for a film having a low moisture absorption rate and a low moisture absorption expansion coefficient as the circuit is progressed to fine pitch. If the moisture absorption coefficient or hygroscopic expansion coefficient is large, a dimensional change due to moisture absorption may occur during the FPCB process, thereby causing a short circuit between the circuits or a problem that the distance between the patterns changes. As a method for solving this problem, there is a process for producing a film using a fluorine-based monomer such as a monomer having a low moisture absorption rate, for example, 2,2-bis (3,4-anhydrodicarboxyphenyl) hexafluoropropane Is known. However, such fluorine-based monomers are not only expensive but also have low reactivity, making it difficult to produce resins.

On the other hand, U.S. Patent No. 5,166,308 discloses the use of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 4,4'-diaminodiphenyl ether and paraphenylene diamine A four-component polyimide film is disclosed. According to the example disclosed in the patent, the film thus produced had a coefficient of thermal expansion of 8.0 to 22.0 ppm / ° C, a coefficient of hygroscopic expansion of 16.8 to 29.8 ppm /% RH, and a coefficient of thermal expansion of 2.26% The film has a moisture absorption rate of 2.84%, which shows improved thermal expansion coefficient, moisture absorption rate and hygroscopic expansion coefficient compared to conventional two- or three-component films, but is insufficient for use in the fine pitch manufacturing process. In addition, the film thus produced has a higher alkaline etching rate than the other films as mentioned in the patent, which means that the alkali resistance is poor. When the alkali resistance is insufficient in the COF production process, there is a problem that the dimensional change occurs in the alkali etching process and it is difficult to maintain the fine pitch interval, and the adhesive strength between the film and the copper foil is lowered by the alkaline solution.

In addition, if the mechanical, thermal, and chemical dimensional stability are not sufficiently secured, and dimensional changes occur due to some factors, the dimensional changes of the IC drive in the continuous mounting process accumulate, And finally the production yield of COF and the like may be remarkably lowered.

Therefore, it is urgently required to develop a polyimide film which simultaneously satisfies both the high modulus of elasticity, the low thermal expansion coefficient, the low moisture absorption rate and the excellent alkali resistance required for electronic equipment materials.

Accordingly, an object of the present invention is to provide a polyimide film which simultaneously satisfies the requirements of high elastic modulus, low thermal expansion coefficient, low moisture absorption rate, low moisture absorption expansion coefficient and excellent alkali resistance required for electronic equipment materials such as FPCB, COF or TAB .

In order to achieve the above object, the present invention provides a process for producing an aromatic dianhydride which comprises reacting 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride and 3,3 ' Biphenyltetracarboxylic acid dianhydride in an amount of 30 to 100 mole% of the total acid dianhydride component and 50 to 100 mole% of paraxylene diamine as an aromatic diamine component in the total diamine component And a polyimide film.

Hereinafter, the present invention will be described in more detail.

The polyimide film according to the present invention comprises 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride as the acid dianhydride component of the polyamide acid resin used as a precursor and 3 , 3 ', 4,4'-biphenyltetracarboxylic dianhydride, and paraphenylenediamine as an essential component as a diamine component.

In the present invention, 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride (BPADA) which is essentially used as an acid dianhydride component of the polyamide acid resin and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) is in the range of 6:94 to 80:20, and the content of BPADA and BPDA in the total acid dianhydride component is 30 to 100 mol%.

When the BPADA is less than 6 mol% based on the BPDA, the adhesion between the polyimide film and the copper foil is deteriorated. In particular, the adhesive strength of the two-layer flexible copper clad laminate (FCCL), which undergoes sputtering and plating, The bending resistance of the circuit may also be reduced. Also, in the present invention, since a large amount of paraphenylene diamine having a rigid structure is used as the diamine component, if the BPADA is less than 6 mol% based on the BPDA, the final film becomes too rigid and the flexing resistance suitable for the FPCB application It is difficult to secure. On the other hand, when BPADA exceeds 80 mol% with respect to BPDA, the glass transition temperature of the final film becomes too low to ensure satisfactory dimensional stability in the packaging process and it may become difficult to control bubble generation in the film production process. In addition, even when a film having good appearance is produced, the coefficient of thermal expansion becomes large, and curling becomes serious in the FPCB manufacturing process and the mounting process.

On the other hand, when the content of BPADA and BPDA in the total acid dianhydride component is less than 30 mol%, the moisture absorption rate and hygroscopic expansion coefficient of the final polyimide film may increase and the alkali resistance may become poor. Particularly, when the molar ratio of BPDA to BPADA and the content of BPDA and BPADA to the total acid dianhydride do not satisfy the above range, the alkali resistance of the final film becomes very poor.

Further, in the present invention, other aromatic dianhydrides, aliphatic acid dianhydrides and alicyclic dianhydrides may be used together with BPADA and BPDA as the acid dianhydride component used in the production of the copolymerized polyamic acid, It is preferable to use an aromatic acid dianhydride from the viewpoint of prevention of decrease in heat resistance. Examples of the aromatic acid dianhydride include pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,4,3 ', 4'-benzophenone tetracarboxylic acid dianhydride, 3,4,3', 4'- Diphenylsulfone tetracarboxylic acid dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5, 8-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride and derivatives thereof. You can choose one or a combination of two or more to work with BPADA and BPDA.

In addition, the copolymerized polyamic acid used for producing the polyimide film of the present invention can be used in an amount of 50 to 100 mol% based on the total diamine component, as the diamine component, paraphenylenediamine (PPD). When the content of PPD is less than 50 mol%, the thermal expansion coefficient of the polyimide film increases and the tensile elastic modulus deteriorates.

In the present invention, an aliphatic diamine, an alicyclic diamine or other aromatic diamine may be used in an amount of 50 mol% or less together with the PPD as a diamine component in the production of a polyamic acid resin. It is preferable to use an aromatic diamine in order to prevent deterioration of heat resistance and elastic modulus of the film, and examples thereof include 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, benzidine, 4'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-bis (4-aminophenoxy) (3-aminophenoxy) diphenylsulfone, 3,6-dioxanthenediamine-10,10-dioxide, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenylsulfide , 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 4,4'-bis (4-aminophenoxy) phenyl) propane, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethyl po Bis (4-aminophenoxy) benzene and its derivatives, and the like. One of these compounds may be selected or a combination of two or more thereof may be used .

The copolymer polyamic acid solution which is a precursor of the polyimide of the present invention can be prepared by using a known method, for example, by using the following methods:

(1) reacting an aromatic tetracarboxylic acid dianhydride and an aromatic dianamine compound having an inferior molar amount thereinto in an organic polar solvent to obtain a prepolymer having an acid anhydride group at both ends thereof, and then reacting the aromatic tetracarboxylic dianhydride with an aromatic diamine A method of polymerizing while adding an aromatic diamine compound such that the compound is substantially equimolar;

(2) reacting an aromatic tetracarboxylic acid dianhydride and an excess molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having an amino group at both ends thereof, and then adding an aromatic tetracarboxylic dianhydride and an aromatic diamine compound A method in which an aromatic tetracarboxylic acid dianhydride is added so as to be substantially equimolar;

(3) dissolving an aromatic diamine in an organic polar solvent and reacting it with substantially equimolar aromatic tetracarboxylic dianhydride to polymerize;

(4) a method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized while adding an aromatic diamine compound so as to be substantially equimolar; or

(5) A method in which a mixture of substantially equimolar aromatic tetracarboxylic acid dianhydride and an aromatic diamine compound is reacted in an organic polar solvent to effect polymerization.

Examples of the solvent which can be used in the step of synthesizing polyamic acid include N, N-dimethylformamide, N-methyl-2-pyrrolidone and N, N-dimethylacetamide as polar aprotic solvents And one of them can be selected or a combination of two or more can be used.

The polyamic acid solution thus prepared is then imidized by conventional thermal or chemical curing methods and converted into polyimide. The thermosetting method is a method in which the imidization reaction is promoted only by heating without using a dehydrating agent or an imidation catalyst. In the chemical curing method, a dehydrating agent represented by an acid anhydride such as anhydrous acetic acid, Quinoline, p-picoline, or pyridine, and the like.

The production process of the polyimide film according to the present invention using the polyamide acid solution prepared as described above is not particularly limited and can be carried out, for example, in the following manner.

First, a dehydrating agent and an imidation catalyst are mixed in a polyamic acid solution at a low temperature, and the mixture is applied or cast on a support such as a support plate, a rotating drum or a steel belt, Is heated to a temperature in the range of 70 占 폚 to 150 占 폚 to activate the dehydrating agent and the catalyst to partially cure and dry the gel film to obtain a gel film as a self-supporting film.

Then, the end portion of the obtained polyamic acid gel film is fixed on the support and heated, and then, in order to completely imidize the remaining amide acid, dehydration cyclization drying is performed by heating at a temperature of 200 to 600 ° C for 3 to 30 minutes . At this time, if the heating temperature is higher than the above range or the heating time is prolonged, the film deteriorates, which is undesirable. Conversely, if the heating temperature is lower than the above range or the heating time is shortened, The film is fragile.

The polyimide film thus prepared has an average thickness in the range of 7 to 125 占 퐉.

The polyimide film according to the present invention has a tensile modulus of 4.5 to 9.0 GPa and a thermal expansion coefficient of 10 to 25 ppm / 占 폚 as measured in a temperature range of 50 to 200 占 폚. Further, when left at room temperature for 24 hours at 99% RH, the moisture absorption rate is 2.0% by weight or less, preferably 1.5% by weight or less, and the moisture absorption coefficient of expansion at 20 to 80% RH at 23 캜 is 20 ppm / Is 18 ppm /% RH or less, and when treated with 5 wt% NaOH aqueous solution at 55 캜 for 4 hours, the alkali reduction rate is 5 wt% or less, preferably 4 wt% or less.

When the tensile modulus of elasticity is less than 4.5 GPa, the resistance against the external force of the film becomes small, and the dimensional change easily occurs even with a small external force. On the other hand, if it exceeds 9.0 GPa, the resistance to external force increases, but the stiffness of the film increases, and the flexural property of the FCCL produced by this film may become poor. On the other hand, when the thermal expansion coefficient is less than 10 ppm / ° C or more than 25 ppm / ° C, the thermal expansion coefficient deviation with the copper foil becomes large, causing curl due to heat in the FCCL manufacturing process, circuit manufacturing process, Repetition of heating and cooling repeatedly tends to cause fatigue fracture due to a variation in the coefficient of thermal expansion, which causes problems in the reliability of the circuit. When the moisture absorption rate is more than 2.0% at a room temperature of 99% RH for 24 hours, the coefficient of hygroscopic expansion of the film becomes large. In the case of the two-layer type FCCL manufactured by the sputtering and plating processes, The sputtering uniformity may be deteriorated. In addition, if the moisture absorption rate is high, the adhesive strength is severely deteriorated under severe conditions such as, for example, in a pressure cooker test (PCT).

When the coefficient of hygroscopic expansion exceeds 20 ppm /% RH, the difference between the dimensions according to the humidity environment in the manufacturing process of the FCCL and the dimension due to the humidity environment during the use of the finished FCCL becomes large, curling may occur, There is a possibility that a distance between circuits changes or a short circuit or disconnection may occur depending on the difference in the dimensional change rate.

Further, the polyimide film of the present invention has a resistance to 5 wt% NaOH aqueous solution at 55 ° C of 5 wt% or less when the alkali reduction rate is measured after immersing for 4 hours. If the weight loss of the alkali exceeds 5 wt%, the alkali resistance is poor and the dimensional change due to the alkaline solution occurs during the circuit production, causing a defect in the drive IC mounting process, and the adhesion between the film and the copper layer may be deteriorated .

The polyimide film of the present invention satisfying the above physical properties is used in electronic equipment such as a flexible circuit board according to a conventional method, and has excellent metal bonding strength, bending resistance, rate of dimensional change after etching and curl can do. For example, the polyimide film of the present invention has a metal bonding strength of 0.62 kN / m or more, preferably 0.68 kN / m or more based on the room temperature peel strength when used in the manufacture of a two-layer flexible copper clad laminate (FCCL) The peel strength is 0.45 kN / m or more, preferably 0.50 kN / m or more. Further, it is possible to impart excellent physical properties such as a flexural resistance of not less than 130 times, preferably not less than 150 times, a rate of dimensional change after etching of -0.05% to +0.05%, and a curl of not more than 2 mm.

The polyimide film according to the present invention satisfies both the high modulus of elasticity, the low coefficient of thermal expansion, the low moisture absorption rate, the low moisture absorption expansion coefficient and the excellent alkali resistance, and is excellent in metal adhesion, bending resistance, It can be usefully used in the field of electronic device parts.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

Example 1

After 635.21 g of dimethylacetamide (DMAc) was charged into the reactor, the reaction temperature was set at 40 占 폚. Thereto were added 17.39 g of p-phenylenediamine (PPD) (60 mol% of the total diamine component) and 21.40 g of 4,4'-diaminodiphenyl ether (DPE) (40 mol% of the total diamine component) And the mixture was stirred until completely dissolved. After the dissolution was completed, 63.21 g of 3,3 ', 3,4'-biphenyltetracarboxylic dianhydride (BPDA) (80 mol% of the total acid dianhydride component) and 2,2'-bis (4- 28.11 g (20 mol% of the total acid dianhydride component) of the dianhydride was adjusted to be substantially equimolar with the acid dianhydride and the diamine was stirred, followed by stirring for 1 hour To obtain a polyamic acid solution in DMAc.

The polyamic acid solution obtained above is mixed with 5 molar equivalents of acetic anhydride (AA) (based on 1 molar equivalent of polyamic acid) and 1 molar equivalent of isoquinoline (IQ) based on 1 molar equivalent of polyamic acid, Was applied on a glass plate to have a uniform thickness, dried at 110 DEG C for 10 minutes and peeled to prepare a gel film. Then, the gel film was fixed to the support frame with a pin, and then heated at 250 캜 for 5 minutes and at 450 캜 for 5 minutes, followed by dehydration ring closure drying to obtain a polyimide film having a thickness of 38 탆.

Example 2

(60 mol%) and BPDAA (24.46 g, 40 mol%) were used as the diamine component, 33.70 g (100 mol%) of PPD as the diamine component, and 54.98 g And a polyimide film having a thickness of 38 mu m was produced by carrying out the same procedure.

Example 3

(60 mol%) of DPD as a diamine component, 23.80 g (40 mol%) of DPE and 67.33 g (77 mol%) of BPDA as an acid dianhydride component, 7.81 g (5 mol% A polyimide film having a thickness of 38 탆 was prepared in the same manner as in Example 1 except that 11.77 g (18 mol%) of melted acid dianhydride (PMDA) was used.

Example 4

(100 mol%) of PPD as diamine component and 7.06 g (8 mol%) of BPDA, 50.49 g (32 mol%) of BPADA and 39.68 g (60 mol%) of PMDA as an acid dianhydride component , A polyimide film having a thickness of 38 탆 was prepared.

Example 5

(30 mol%) of DPE and 7.06 g (8 mol%) of BPDA as an acid dianhydride component, 37.48 g (24 mol%) of BPADA and 23.39 g of PMDA A polyimide film having a thickness of 38 탆 was produced in the same manner as in Example 1, except that 44.47 g (68 mol%) was used.

Comparative Example 1

(30 mol%) of DPE, and 39.69 g (40 mol%) of BPDA and 44.25 g (60 mol%) of PMDA as the diamine component, 25.0 g , A polyimide film having a thickness of 38 탆 was prepared.

Comparative Example 2

(60 mol%) of DPD and 20.40 g (40 mol%) of DPE and 35.10 g (60 mol%) of PMDA and 55.69 g (40 mol%) of BPADA as the dianhydride component , A polyimide film having a thickness of 38 탆 was prepared.

Comparative Example 3

Except that 63.70 g of DMAc, 62.20 g (100 mol%) of DPE was used as a diamine component, and 67.80 g (100 mol%) of PMDA was used as an acid dianhydride component. To prepare a polyimide film.

Comparative Example 4

(70 mol%) of DPE and 59.68 g (80 mol%) of BPDA as an acid dianhydride component and 26.55 g (20 mol%) of BPADA as a diamine component , A polyimide film having a thickness of 38 탆 was prepared.

Test Example 1

The polyimide films prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to additional heat treatment at 320 DEG C for 10 minutes under an emulsion force, and various performances were evaluated by the following methods. The results are shown in the following Table 1 Respectively.

(1) Tensile modulus

It was measured according to the method of ASTM D882 using an UTM instrument of Instron.

(2) Coefficient of thermal expansion

Using a TMA-2940 manufactured by TA Corporation, a load of 0.05 N was applied. The substrate was heated from 400 ° C to room temperature for 5 minutes at a heating rate of 10 ° C per minute, and then cooled to 30 ° C at a cooling rate of 10 ° C per minute. The thermal expansion coefficient in the range of 50 to 200 캜 was measured during the cooling process.

(3) Absorption rate

The polyimide film was dried at 150 占 폚 for 30 minutes and its weight was measured (Ww1). This film was treated for 24 hours in a constant temperature and humidity chamber under conditions of 23 DEG C and 99% RH. The surface of the film thus treated was polished and again weighed (Ww2). The moisture absorption rate was calculated from the measured Ww1 and Ww2 by the following equation (1).

Moisture absorption rate (% by weight) = [(Ww2 - Ww1) / Ww1] x100

(4) Moisture expansion coefficient

The polyimide film was allowed to stand at 23 캜 and 20% RH for 24 hours, and its length was measured (L1). The film was again left under the conditions of 23 ° C and 80% RH for 24 hours, and its length (L2) was measured. The coefficient of hygroscopic expansion was calculated by the following formula (2).

(5) Alkali reduction rate

The polyimide film was dried at 150 DEG C for 30 minutes and its weight was measured (Wa1). Subsequently, this film was completely immersed in an aqueous 5 wt% NaOH solution and allowed to stand at 55 캜 for 4 hours. The treated film was washed with distilled water for 5 minutes to completely remove NaOH remaining on the surface, dried again in an oven at 150 ° C. for 30 minutes, and the weight thereof was measured (Wa2). From the measured Wa1 and Wa2, the alkali reduction rate was measured by the following equation (3). The alkali reduction rate generally has a negative value, and the smaller the number, the more the alkali resistance is poor.

Alkali reduction rate (% by weight) = [(Wa2-Wa1) / Wa1] x100

From the results shown in Table 1, it can be seen that the polyimide film produced in the example according to the present invention has better physical properties than the polyimide film according to the comparative example.

Examples 6 to 10 and Comparative Examples 5 to 8: Preparation of two-layer flexible copper-clad laminate (FCCL)

Two-layer type flexible copper clad laminate (FCCL) was produced by the following method using the polyimide films obtained in Examples 1 to 5 and Comparative Examples 1 to 4.

First, the surface of the polyimide film was subjected to a reduced pressure plasma treatment in oxygen and argon atmosphere, followed by vacuum sputtering using nickel and chromium alloy. Subsequently, this substrate was vacuum-sputtered again with copper as a target to prepare a substrate to which a metal layer was adhered. At this time, the thickness of the metal layer was fixed to 2500 Å. The obtained deposited film was electrolytically plated again to finally produce a 2-layer type FCCL plated with copper of 8 mu m +/- 1 mu m.

The thus prepared two-layer type FCCL was etched to form a pattern with a circuit width of 1 mm and a space width of 1.5 mm.

Test Example 2

The properties of the two-layer type FCCL prepared by the methods of Examples 6 to 10 and Comparative Examples 5 to 8 were measured according to the following method, and the results are shown in Table 2 below.

(1) Metal bond strength

(1) Peel strength at room temperature: The peel strength at 90 ° was measured at room temperature according to the method of IPC TM 650 2.4.9, and the average value was measured ten times.

(2) Pressure Cooker Test (PCT) Peel strength: The produced circuit was treated for 96 hours at 120 ° C, 100% RH and 2 atmospheric pressure, and then the 90 ° peel strength was measured 10 times and the average was taken.

(2) Flexibility

The manufactured circuit was mounted on an MIT-DA tester manufactured by Toyo Seiki Co., Ltd., and the bending angle was measured with a bending angle of ± 135 ° and a load of 200 g until the disconnection occurred.

(3) Dimensional change rate after etching

The pre-circuit length of the specified section of the fabricated FCCL was measured (Le1). Then, the circuit is fabricated by etching the FCCL, and the length of the previously designated section is re-measured (Le2) to calculate the dimensional change rate after etching according to the following equation (4).

(%) After etching = [(Le2-Le1) / Le1] x 100

(4) Curl

The fabricated FCCL was cut into a size of 10 cm × 10 cm and heat-treated at 400 ° C. for 30 seconds in order to simulate an FPCB manufacturing process or a mounting process. The sample was placed on a flat floor and the height at which the end floated from the floor was measured. The smaller the result of the curl measurement, the better.

From the results shown in Table 2, it can be seen that the FCCL using the polyimide film excellent in elastic modulus, thermal expansion coefficient, moisture absorption rate, hygroscopic expansion coefficient and alkali resistance, produced in the example according to the present invention, The flexural resistance, the dimensional change rate after etching, and curl can be confirmed.

As described above, the polyimide film according to the present invention satisfies both the high modulus of elasticity, the low coefficient of thermal expansion, the low moisture absorption rate, the low moisture absorption coefficient and the excellent alkali resistance, Dimensional change rate and curl, it can be usefully used in the field of electronic device parts.

Claims (8)

As the aromatic acid dianhydride component, 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride are reacted with total acid And 30 to 100 mol% of dianhydride components, wherein the aromatic diamine component comprises para-phenylenediamine in an amount of 50 to 100 mol% of the total diamine component, Wherein the molar ratio of the 2,2'-bis (4- (3,4-dicarboxyphenoxy) phenyl) propane dianhydride to the 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride is from 6: 80:20. ≪ / RTI > delete The method according to claim 1, Wherein said acid dianhydride component is selected from the group consisting of pyromellitic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,4,3 ', 4'-benzophenone tetracarboxylic acid dianhydride, 3,4,3' Diphenylsulfone tetracarboxylic acid dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5, Characterized in that it further comprises at least one aromatic acid dianhydride component selected from the group consisting of 8-naphthalene tetracarboxylic acid dianhydride, 3,4,9,10-perylene tetracarboxylic acid dianhydride, and derivatives thereof. Mid-film. The method according to claim 1, Wherein the diamine component is selected from the group consisting of 4,4'-diaminodiphenyl propane, 4,4'-diaminodiphenyl methane, benzidine, 4,4'-diaminodiphenyl ether, , 4,4'-diaminodiphenylsulfone, 4,4'-bis (4-aminophenoxy) diphenylsulfone, 4,4'-bis Dioxane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenyl ether, 3,4'-diamino Diphenyl ether, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 4,4'-bis (4-aminophenoxy) biphenyl, 2,2'- Silane) phenyl) propane, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, Orthophenylenediamine, 1,3-bis (4-aminophenoxy ) ≪ / RTI > benzene, and derivatives thereof. ≪ Desc / Clms Page number 13 > The method according to claim 1, Wherein the film has a tensile modulus of 4.5 to 9.0 GPa and a thermal expansion coefficient of 10 to 25 ppm / 占 폚 at a temperature of 50 to 200 占 폚. The method according to claim 1, Wherein the film has a moisture absorption rate of not more than 2.0% by weight when the film is allowed to stand at 99% RH for 24 hours at room temperature and a moisture absorption coefficient of expansion of not more than 20 ppm /% RH at 20 to 80% RH at 23 占 폚. Mid-film. The method according to claim 1, Wherein the film has an alkali reduction rate of 5% by weight or less when the film is treated with a 5 wt% NaOH aqueous solution at 55 캜 for 4 hours. An electronic device part comprising a polyimide film according to any one of claims 1 to 7.