JP3932506B2 - Polyimide film, printed circuit and metal wiring board - Google Patents

Description

【００６９】
【表２】

［比較例１］
５００ｃｃのガラス製フラスコに、ＤＭＡｃ１５０ｍｌを入れ、３４’ＯＤＡをＤＭＡｃ中に供給して溶解させ、ＰＭＤＡを溶解させ、室温で、約１時間攪拌し、テトラカルボン酸二無水物成分とジアミン成分が約１００モル％化学量論で表１に示す組成の成分からなるポリアミド酸濃度２０重量％の溶液を調製した。
【００７０】
このポリアミド酸溶液を、実施例１と同じ方法で処理して、厚さ約５０μｍのポリイミドフィルムを得た。得られたポリイミドフィルムの特性値評価結果を表２に示した。
【００７１】
表１〜表２に記載された結果から明らかなように、本願で示される組成範囲のＰＭＤＡ、４４’ＯＤＡおよび３４’ＯＤＡからなる化学転化法で得られた本発明のランダムポリイミドフィルムは、本願範囲外の同種３成分ポリイミドフィルムに比較して、高弾性率、低熱膨張係数、低熱収縮率、および蒸着後の平面性を同時に満足しており、可撓性の印刷回路，ＣＳＰ，ＢＧＡまたはＴＡＢテープ用の金属配線板基材としての好適な性能を有するものである。
【００７２】
【発明の効果】
以上説明したように、本発明のポリイミドフィルムは、本願範囲外の同種３成分組成物により得られるポリイミドフィルムに比して、可撓性の印刷回路，ＣＳＰ，ＢＧＡまたはＴＡＢテープ用の金属配線板基材に適用した場合に、高弾性率、低熱膨張係数、低熱収縮率、および蒸着後の平面性を同時に満足しうるものである。
【００７３】
したがって、本発明のポリイミドフィルムを基材として、その表面に金属配線を施してなる可撓性の印刷回路，ＣＳＰ，ＢＧＡまたはテープ自動化接合テープ用の金属配線板は、高弾性率、低熱膨張係数、低熱収縮率、および蒸着後の平面性を均衡して高度に満たすという高性能な特性を発現する。[0001]
BACKGROUND OF THE INVENTION
When the present invention is used as a metal wiring board substrate for a flexible printed circuit or tape automated bonding tape (hereinafter referred to as TAB tape) formed by providing metal wiring on its surface, Polyimide film excellent in high elastic modulus, low thermal expansion coefficient and high heat resistance, and flexible printed circuit based on the polyimide film and The present invention relates to a metal wiring board for TAB tape.
[0002]
[Prior art]
The TAB tape has ultra-thin metal wiring on the surface of the heat-resistant film, which is the base material, and “windows” for mounting integrated circuit chips (ICs) on the base material. In the vicinity, a sprocket for precisely feeding the TAB tape is provided.
[0003]
In the TAB tape, the IC is inserted into a “window” opened in the TAB tape, joined to the metal wiring provided on the surface of the TAB tape, and then the TAB tape on which the IC is mounted is used as a printed circuit for electronic equipment wiring. It is used to automate the process of mounting an IC on an electronic circuit by bonding, simplify the process, improve productivity, and improve the electrical characteristics of an electronic device on which the IC is mounted.
[0004]
The TAB tape has a three-layer structure in which a conductive metal foil is laminated on the surface of a heat-resistant base film with an adhesive such as a polyester base, an acrylic base, an epoxy base, or a polyimide base. The thing of the two-layer structure which laminates | stacks a conductive metal layer directly on the surface of a conductive base film without using an adhesive agent is used.
[0005]
Therefore, the base film of the TAB tape is required to have heat resistance, especially when joining the IC and the metal wiring on the TAB tape or joining the printed circuit for wiring the electronic device and the TAB tape. Conventionally, a polyimide film has been used so as to withstand high temperatures such as solder welding applied to the base film. In particular, since an object having a deposited metal layer is required to have heat resistance, aromatic polyimide having excellent heat resistance is used for that purpose.
[0006]
However, when a polyimide film and a metal foil or a metal layer are laminated and a metal wiring is formed by chemically etching the metal foil or the metal layer, a TAB caused by a difference in dimensional change between the polyimide film and the metal due to heat received. When the deformation of the tape is large, when the IC is mounted or when the TAB tape with the IC is bonded to the printed circuit for electronic equipment wiring, the workability is remarkably impaired or sometimes the work is made impossible. Therefore, it is required that the thermal expansion coefficient of the polyimide film be approximated to that of metal to reduce the deformation of the TAB tape.
[0007]
Furthermore, reducing the dimensional change due to the tensile and compressive forces applied to the TAB tape mounted with the IC and bonded to the printed circuit for electronic equipment wiring can also reduce the fineness of the metal wiring, reduce the strain load on the metal wiring, and It is important for reducing the strain load of the mounted IC, and the polyimide film as the substrate is required to have a higher elastic modulus.
[0008]
On the other hand, in FPC, which is the main use of polyimide film, printed circuit board products that have grown rapidly in recent years include high-density flexible substrates (http://www2.hitachi-cable.co.jp/H#cable/news/ 970821 / microbga.htm, or http://www.dnp.co.jp/jis/news99/991012.html). This means that the wiring width / inter-wiring distance (hereinafter abbreviated as inter-wiring distance) is 25-40 μm or less, and the circuit density is significantly higher than the conventional 100 microns (the smaller the wiring pitch is, the higher the circuit density is, the smaller the wiring pitch). Is growing. By 2004, the market for high-density flexible boards is expected to reach 5 to 6 billion dollars (Electronic Packaging Technology, October 2001, Vol. 17, No. 10). The deposition type mainly developed on this high-density flexible substrate deposits metal at a high temperature, so that the polyimide film as the adherend surface may lose heat. The present inventors have clarified in Japanese Patent Application No. 2000-253525 that polyimide films derived from 44′ODA, 34′ODA and PMDA are suitable for this application, but have dimensional stability and properties that do not lose heat during vapor deposition. It was not possible to clearly show a composition that can achieve both.
[0009]
[Problems to be solved by the invention]
The present invention has been achieved as a result of examining the above-described problems in the prior art as a subject, and has been achieved for a flexible printed circuit, CSP, BGA or TAB tape having a metal wiring on its surface. It is intended to provide a polyimide film excellent in high elastic modulus, low thermal expansion coefficient, and high heat resistance when applied to a metal wiring board substrate, and a metal wiring circuit board based on the polyimide film. is there. In particular, the inventors have found a composition range that can be used for vapor deposition type high-density flexible substrates.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the polyimide film of the present invention comprises pyromellitic dianhydride and more than 40 mol% to 50 mol% of 4,4′-oxydianiline and 50 mol% based on diamine. Polyamic acid comprising 3,4′-oxydianiline in excess to 60 mol% or less Obtained by imide conversion A polyimide film manufactured from
[0011]
Moreover, the polyimide film of this invention can be obtained by combining the general manufacturing method of a polyimide.
[0012]
Furthermore, the flexible printed circuit of the present invention ,and A metal wiring board for TAB is characterized in that the above polyimide film is used as a base material and metal wiring is applied to the surface thereof.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration and effects of the present invention will be described in detail.
[0014]
The polyimide constituting the film of the present invention is preferably a random polymer.
[0015]
The polyimide polymer of the present invention balances high elasticity, low thermal expansion coefficient, and high heat resistance when applied to flexible printed circuits, CSP, BGA or TAB tape metal wiring board substrates. A polyimide film satisfying the above can be realized.
[0016]
The diamine used in the present invention is obtained by using a flexible diamine such as 4,4′-oxydianiline and a quasi-linear diamine such as 3,4′-oxydianiline. It is produced by converting the polyamic acid obtained by imide conversion. Other diamines can be used in combination within a range of addition amounts that do not impair the object of the present invention.
[0017]
In the present invention, 4,4′-oxydianiline increases the flexibility of the film, increases the glass transition temperature (Tg), and makes it difficult to lose heat during vapor deposition. Accordingly, when the amount of 4,4′-oxydianiline is small, the heat shrinkage ratio becomes too large and the heat resistance is deteriorated. In the present invention, 3,4'-oxydianiline acts to lower the glass transition temperature (Tg), increase the elongation of the film, and improve the film forming property. If the amount of 3,4′-oxydianiline is large, the heat shrinkage ratio becomes too large and the heat resistance is deteriorated.
[0018]
When 3,4′-oxydianiline is 50 mol% or less, the elongation of the film becomes small and the film-forming property may be deteriorated or the rigidity may be insufficient. On the other hand, when 3,4'-oxydianiline exceeds 60 mol%, the glass transition temperature becomes low, or the heat shrinkage rate at a high temperature becomes too high.
[0019]
The tetracarboxylic dianhydride used in the present invention is pyromellitic dianhydride, but tetracarboxylic dianhydride and the like can be used in combination within a range of addition amounts that do not impair the object of the present invention. For example, biphenyl tetracarboxylic dianhydride or benzophenone tetracarboxylic dianhydride can be added in less than 50 mol%.
The resulting polyamic acid is produced by imide conversion.
[0020]
The elastic modulus of the polyimide film can be adjusted by the use ratio of the 3,4'-oxydianiline component in the diamine component used when the polyamic acid is produced. When a large amount of the 3,4′-oxydianiline component is used, the high elastic modulus and dimensional stability are improved, but the heat resistance is disadvantageously reduced. Therefore, it is necessary to carefully adjust the molar ratio of each component in order to balance the respective characteristic values.
[0021]
The polyamic acid of the present invention has a molar ratio of the tetracarboxylic dianhydride component and the diamine component of about 0.90 to 1.10, preferably 0.95 at a temperature of 175 ° C. or lower, preferably 90 ° C. or lower. ˜1.05, more preferably 0.98 to 1.02, and it is produced by reacting each component in a non-reactive organic solvent.
[0022]
Each of the above components may be separately supplied to the organic solvent one after another, or may be simultaneously supplied, or the organic solvent may be supplied to the mixed components, in order to perform a uniform reaction. It is preferable to sequentially add each component to the organic solvent.
[0023]
The supply order in the case of supplying each component sequentially is determined as appropriate.
[0024]
The time required for producing the polyamic acid may be determined by the reaction temperature and the raw material ratio, but it is experientially about 1 minute to about 20 hours.
Specifically, pyromellitic dianhydride (PMDA) as a tetracarboxylic dianhydride component, and 4,4′-oxydianiline (44′ODA) and 3,4′-oxydianiline (34 as diamine components) A production example of a polyimide polymer using 'ODA) will be described below.
[0025]
First, 34′ODA is dissolved in dimethylacetamide (DMAc) as an organic solvent, and a part of PMDA is added to complete the reaction.
[0026]
Next, after 44′ODA is added to the solution and dissolved, the remaining PMDA is added to the solution and reacted to obtain a three-component polyamic acid solution in which the acid anhydride and the diamine are substantially equimolar.
[0027]
In this case, a small amount of 34′ODA is added to the PMDA supplied first, or the molar ratio of PDA and PMDA to be reacted first is made unequal, so that the terminal can be sufficiently reacted with an excess amount of the diamine component. It is possible to control the chain of molecular chains by adding a sealant, but in order to make the effect of this composition effective, the molar ratio of 34′ODA, 44′ODA and PMDA is substantially increased. It is preferable to use random polymers that are equally equivalent.
[0028]
The end-capping agent to be used can be preferably added by adding a end-capping agent such as dicarboxylic anhydride or silylating agent in the range of 0.001 to 2% with respect to the solid content (polymer concentration). As the dicarboxylic anhydride, acetic anhydride or phthalic anhydride, non-halogen hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis (trimethylsilyl) urea are particularly preferably used as the silylating agent. .
[0029]
The production end of the polyamic acid is determined by the polyamic acid concentration of the solution and the viscosity of the solution. In order to accurately determine the viscosity of the solution at the end point, it is effective to add a part of the last component to be supplied as a solution of the organic solvent used for the reaction, but the polyamic acid concentration is not lowered so much. Such adjustment is necessary.
[0030]
The polyamic acid concentration in the solution is 5 to 40% by weight, preferably 10 to 30% by weight.
[0031]
The organic solvent is preferably selected from those that are non-reactive with each component and the polyamic acid that is the polymerization product, can dissolve all of the components, and dissolve the polyamic acid.
[0032]
Desirable organic solvents include N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone, and the like. Alternatively, they can be mixed and used in some cases together with a poor solvent such as benzene.
[0033]
In producing the polyimide film of the present invention, the polyamic acid solution thus obtained is pressurized with an extruder or a gear pump and fed to the polyamic acid film production process.
[0034]
The polyamic acid solution is mixed to the raw material, filtered to remove foreign matters, solids and high-viscosity impurities generated in the polymerization process, and formed into a film shape through a film forming die or a coating head, Extruded onto a rotating or moving support and heated from the support to produce a polyamic acid-polyimide gel film in which the polyamic acid is partially imide converted. This gel film becomes self-supporting and can be peeled off from the support. When it becomes, it peels from a support body, is introduce | transduced into a dryer, is heated with a dryer, a solvent is dried, A polyimide film is manufactured by completing imide conversion.
[0035]
At this time, the use of a 20 μm cut metal fiber sintered filter is effective for removal of the gel material produced in the middle. A metal fiber sintered filter with a cut of 10 μm is more preferable, and a metal fiber sintered filter with a cut of 1 μm is most preferable.
[0036]
The method of imide conversion of polyamic acid employs either a thermal conversion method by heating alone, a chemical conversion method in which the polyamic acid mixed with the imide conversion agent is heat-treated, or the polyamic acid is immersed in a bath of the imide conversion agent. However, in the present invention, when the chemical conversion method is applied to a flexible printed circuit, a metal wiring board substrate for CSP, BGA, or TAB tape, compared with the thermal conversion method, it is highly elastic. It is suitable for achieving a high degree of balance among the rate, the low thermal expansion coefficient, the dimensional stability and the film forming property.
[0037]
In addition, the method of mixing the imide conversion agent with the polyamic acid by the chemical conversion method, and heat-treating after forming into a film form has the advantage that the time required for imide conversion is short and the imide conversion can be performed uniformly. Is easy to peel off, and also has the advantage of being able to handle imide conversion chemicals that have strong odor and need to be sequestered in a closed system, so that it can be used as a bath for conversion chemicals and dehydrating agents after forming a polyamic acid film. It is preferably employed as compared with the dipping method.
[0038]
In the present invention, as the imide conversion agent, a tertiary amine that promotes imide conversion and a dehydrating agent that absorbs moisture generated by imide conversion are used in combination. Tertiary amines are added and mixed with polyamic acid in substantially equimolar or slightly excessive amount, and the dehydrating agent is added in about twice the molar amount or slightly excessive amount of polyamic acid, but adjusts the peeling point from the support. Is adjusted appropriately.
[0039]
The imide conversion agent may be added at any time when the polyamic acid solution reaches the film forming die or the coating head from the time when the polyamic acid is completely polymerized. Then, it is preferable to add a little before reaching the film forming die or the coaching head and to mix with a mixer.
[0040]
As the tertiary amine, pyridine or β-picoline is suitable, but α-picoline, 4-methylpyridine, isoquinoline, triethylamine and the like can also be used. The amount used is adjusted according to each activity.
[0041]
Acetic anhydride is most commonly used as the dehydrating agent, but propionic anhydride, butyric anhydride, benzoic acid, formic anhydride, and the like can also be used.
[0042]
The polyamic acid film containing the imide conversion agent is subjected to imide conversion by heat received from the support and the opposite surface space on the support, and becomes a partially polyimide-converted polyamic acid-polyimide gel film, which is peeled off from the support. .
[0043]
In this case, as the amount of heat applied from the support and the opposite surface space increases, imide conversion is promoted and peels faster, but if the amount of heat is excessive, the gas of the organic solvent between the support and the gel film deforms the gel film. Therefore, it is desirable to determine the amount of heat in consideration of the position of the peeling point and the film defect.
[0044]
The gel film peeled from the support is introduced into a dryer, and the drying of the solvent and the imide conversion are completed.
[0045]
This gel film contains a large amount of organic solvent, and its volume is greatly reduced during the drying process. Therefore, in order to concentrate the dimensional shrinkage due to the volume reduction in the thickness direction, the both ends of the gel film are gripped by the tenter clip, and the gel film is introduced into the dryer (tenter) by the movement of the tenter clip. In general, the drying of the solvent and the imide conversion are performed consistently by heating.
[0046]
This drying and imide conversion are performed at a temperature of 200 to 500 ° C. The drying temperature and the imide conversion temperature may be the same temperature or different temperatures, but at the stage of drying a large amount of solvent, lower the temperature to prevent bumping of the solvent, and if there is no risk of bumping of the solvent, raise the temperature. It is preferable to increase the temperature stepwise so as to promote imide conversion.
[0047]
In the tenter, the distance between the tenter clips at both ends of the film can be expanded or reduced to stretch or relax. As the draw ratio, the machine axis direction is 1.0 to 1.3 times. The draw ratio in the width direction is 0.9 to 1.3 times.
[0048]
Preferably, a cut sheet-like polyimide film obtained by imide conversion by a chemical conversion method can be produced by cutting from a continuous film produced as described above. As shown in the examples, a random polyamic acid is produced in a resin or glass flask, and a mixed solution obtained by mixing the polyamic acid solution with a chemical conversion agent is used as a support such as a glass plate. Cast on top, heat, and partially imide-converted as a self-supporting polyamic acid-polyimide gel film, peeled off from the support, fixed to a metal fixing frame, etc. and heated while preventing dimensional changes Thus, it can be produced by a method of solvent drying and imide conversion.
[0049]
Thus, the polyimide film of the present invention obtained by imide conversion by the chemical conversion method is used for flexible printed circuits, CSP, BGA, or TAB tape even when compared with the polyimide film obtained by the thermal conversion method. When applied to the metal wiring board substrate, it is suitable for simultaneously satisfying a high elastic modulus, a low thermal expansion coefficient, and a low hygroscopic expansion coefficient, and has excellent thermal dimensional stability.
[0050]
Therefore, a flexible printed circuit formed by using the polyimide film of the present invention as a base material and a metal wiring on the surface thereof, a metal wiring board for CSP, BGA or TAB has a high elastic modulus, a low thermal expansion coefficient, a thermal dimension. It exhibits high performance characteristics that satisfy both stability and film-formability at the same time.
[0051]
In the polyimide film of the present invention, the elastic modulus is preferably 3.5 to 4.5 GPa. If the elastic modulus is small, the film travelability is poor and difficult to handle, and if it is high, the flexibility is poor.
[0052]
Whether the linear expansion coefficient is too large or too small, the curl becomes too large when bonded to a metal, and the thermal expansion coefficient is preferably 16 to 24 ppm / ° C. More preferably, it is 17.5-22.5 ppm / ° C. When the deposited metal is directly laminated, there is no adhesive layer having a role of a stress buffer layer. Therefore, the thermal expansion coefficient needs to be controlled more strictly than when the metal is laminated via the adhesive.
[0053]
The water absorption is 2% or less, particularly preferably 1% or less.
[0054]
Metals such as copper, nickel, chromium, and silicon, and metal oxides such as silicon dioxide, indium oxide, and tin oxide, all have a melting point of 1000 ° C. or higher. Is exposed to high temperature, it is better that the heat shrinkage rate at high temperature is small. For example, it may be difficult to use when the thermal shrinkage at 350 degrees exceeds 1%. Preferably it is 0.5% or less, More preferably, it is 0.2% or less.
[0055]
Further, since the film is exposed to a high temperature close to 300 ° C. during the solder bath process, it is preferable that the thermal contraction rate is small. As the environmental problem of lead elution is taken up, the solder melting point tends to be used on the high temperature side, and there is an increasing demand to reduce the thermal shrinkage at 350 ° C. If the thermal shrinkage rate exceeds 0.5%, the flatness is deteriorated and it may be difficult to use. Preferably it is 0.2%, More preferably, it is 0.1% or less.
[0056]
Unlike the linear expansion coefficient, the thermal contraction rate is an irreversible change, so the smaller the absolute value is better. As a preferable method for reducing the heat shrinkage rate, a method of performing heat treatment at a multi-stage temperature can be mentioned. In this case, the initial heat treatment temperature is higher than the temperature at which heat treatment is subsequently performed. Specific methods include a method in which a roll wound with a film is left in a heating oven and a method in which heat treatment is performed under no tension, but from the viewpoint of reducing heat shrinkage stress, heat treatment without tension is preferable. . The temperature for the heat treatment is preferably 200 ° C to 400 ° C. More preferably, it is 300 to 350 degreeC. The cooling rate after the heat treatment is preferably 1 ° C to 1000 ° C per minute. Furthermore, 5-100 degreeC is preferable.
[0057]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. Each film characteristic value is measured by the following method.
[0058]
In the following examples, the abbreviation DMAc is dimethylacetamide, PMDA is pyromellitic dianhydride, 44'ODA is 4,4'-oxydianiline, and 34'ODA is 3,4 '. -Abbreviation for oxydianiline.
(1) Elastic modulus and elongation at break
The elastic modulus was determined from the slope of the initial rising portion of the tension-strain curve obtained at a tensile speed of 300 mm / min with a Tensilon type tensile tester manufactured by ORIENREC at room temperature according to JISK7113.
[0059]
The elongation at break was taken when the sample broke.
(2) Thermal expansion coefficient
The coefficient of thermal expansion was 50 at the time of the second rise (fall) temperature using a TMA-50 type thermomechanical analyzer manufactured by Shimadzu Corporation at a rate of temperature increase of 10 ° C./min and a rate of temperature decrease of 5 ° C./min. It calculated | required from the dimensional change between 0 degreeC and 200 degreeC.
(3) Evaluation of warpage of metal laminate
The polyimide film is dried in an oven at 350 ° C. for 10 minutes, and then 0.5 μm thick copper is ion-deposited. The obtained metal laminate was cut into a sample size of 35 mm × 120 mm, left in an atmosphere at 25 ° C. and 60 RH% for 24 hours, and then warpage of each sample was measured. For warping, a sample was placed on a glass plate, and the heights of the four corners were measured and averaged. Evaluation criteria were determined as follows according to the amount of warpage. When the x level is used as a metal wiring circuit board, it is a level at which handling becomes difficult at the time of transport in a subsequent process.
[0060]
○ Warpage less than 1mm
△ Warpage amount 1mm or more and less than 3mm
× Warpage amount 3mm or more
(4) Film forming properties
The prepared film was stretched by a biaxial constant-speed biaxial stretching method at 400 ° C. using a research polymer film biaxial stretching apparatus (BIX-703, manufactured by Iwamoto Seisakusho Co., Ltd.) to determine the film break area. Preheating time 60 seconds, one-side stretching speed 10 cm / min.
[0061]
◎: Extremely good Breaking stretch plane ratio exceeds 1.3 times
○: Good The ratio of the stretched stretched surface is 1.1 to 1.2 times
Δ: No practical problem Breaking stretch ratio is 1 to 1.1 times
X: Difficult to form film Breaking stretch ratio is 1 times or less
(5) Thermal contraction rate
A. 300 ° C heat shrinkage
According to JIS-C2318, the dimensional change rate before and after heating at 300 ° C. for 1 hour is measured.
[0062]
Thermal contraction rate C (%) = 100 (A−B) / A
However, A ... Film dimensions before heating
B ... Film dimensions after heating
◎; 0.1% or less
○: Over 0.1% to 0.2% or less
Δ: Over 0.2% to 0.5% or less
X: Over 0.5%.
[0063]
B. 350 ° C heat shrinkage
According to JIS-C2318, the dimensional change rate before and after heating at 350 ° C. for 30 minutes is measured.
[0064]
Thermal contraction rate C (%) = 100 (A−B) / A
However, A ... Film dimensions before heating
B ... Film dimensions after heating
◎; 0.2% or less
○: Over 0.2% to 0.5% or less
Δ: Over 0.5% to 1% or less
X: Over 1%.
(8) Glass transition temperature (Tg)
It is determined from tan δ and E ′ (storage modulus) from dynamic viscoelasticity measured by a tensile method using a rheometric viscoelasticity analyzer (RSA2). The temperature at which the slope of E ′ changes three times or more from 280 ° C. to 380 ° C. or the temperature at which the tan δ peak showing the maximum value rises is defined as Tg.
[0065]
[Example 1]
In a 500 cc glass flask, 150 ml of DMAc is added, 34′ODA is fed into DMAc to dissolve, and then 44′ODA and PMDA are fed in sequence, followed by stirring at room temperature for about 1 hour. Finally, a solution with a polyamic acid concentration of 20% by weight was prepared, in which the tetracarboxylic dianhydride component and the diamine component consisted of components having the composition shown in Table 1 at about 100 mol% stoichiometry.
[0066]
A mixed solution was prepared by mixing 30 g of this polyamic acid solution with 12.7 ml of DMAc, 3.6 ml of acetic anhydride and 3.6 ml of β-picoline, and this mixed solution was cast on a glass plate. Was heated for about 4 minutes on a hot plate heated to form a self-supporting polyamic acid-polyimide gel film, which was peeled from the glass plate.
[0067]
This gel film is fixed to a metal fixing frame having a large number of pins, heated for 30 minutes while being heated from 250 ° C. to 330 ° C., then heated at 400 ° C. for about 5 minutes, and then taken to room temperature over about 1 hour. Cooled and removed. A polyimide film having a thickness of about 50 μm was obtained. Table 1 shows the evaluation results of the characteristic values of the obtained polyimide film.
[0068]
[Table 1]

[0069]
[Table 2]

[Comparative Example 1]
In a 500 cc glass flask, 150 ml of DMAc is added, 34′ODA is fed into DMAc and dissolved, PMDA is dissolved, and stirred at room temperature for about 1 hour. The tetracarboxylic dianhydride component and the diamine component are about A solution having a polyamic acid concentration of 20% by weight comprising the components shown in Table 1 at 100 mol% stoichiometry was prepared.
[0070]
This polyamic acid solution was treated in the same manner as in Example 1 to obtain a polyimide film having a thickness of about 50 μm. The evaluation results of the characteristic values of the obtained polyimide film are shown in Table 2.
[0071]
As is clear from the results described in Tables 1 and 2, the random polyimide film of the present invention obtained by the chemical conversion method comprising PMDA, 44′ODA and 34′ODA in the composition range shown in the present application is Compared to the same kind of three-component polyimide film out of the range, it simultaneously satisfies the high elastic modulus, low thermal expansion coefficient, low thermal contraction rate, and flatness after vapor deposition, flexible printed circuit, CSP, BGA or TAB It has suitable performance as a metal wiring board substrate for tape.
[0072]
【The invention's effect】
As described above, the polyimide film of the present invention is a flexible printed circuit, CSP, BGA or TAB tape metal wiring board as compared with a polyimide film obtained by using the same three-component composition outside the scope of the present application. When applied to a substrate, it can satisfy a high elastic modulus, a low thermal expansion coefficient, a low thermal contraction rate, and flatness after vapor deposition at the same time.
[0073]
Therefore, a flexible printed circuit, CSP, BGA or tape automatic bonding tape metal wiring board formed by using the polyimide film of the present invention as a base material and metal wiring on the surface thereof has a high elastic modulus and a low thermal expansion coefficient. In addition, it exhibits high performance characteristics that balance the low thermal shrinkage rate and the flatness after deposition to a high degree.

Claims (3)

From pyromellitic dianhydride and from 40 mol% to 50 mol% or less of 4,4′-oxydianiline and from 50 mol% to 60 mol% of 3,4′-oxydianiline based on diamine A polyimide film produced from a polyimide obtained by converting an obtained polyamic acid into an imide . As a substrate a polyimide film according to claim 1, the flexible printed circuits of which is characterized by comprising subjecting a metal wiring on its surface. A metal wiring board for tape automated joining tape, wherein the polyimide film according to claim 1 is used as a base material and metal wiring is applied to the surface thereof.