JP3783870B2 - Film substrate for semiconductor mounting - Google Patents

Description

  The present invention relates to a film substrate suitable for application to a so-called COF in which a semiconductor chip is mounted on a film substrate using a flip chip bonding technique. More specifically, the present invention relates to a copper foil sufficient to form fine lines. The present invention relates to a film substrate for semiconductor mounting which has sufficient adhesive strength and line-to-line insulation reliability sufficient to realize fine line-to-line.

The COF technology is attracting attention as a new semiconductor substrate film substrate technology that replaces the TAB technology. TAB technology has been used recently, mounting of semiconductor devices, especially liquid crystal display elements, EL display elements, electrophoretic display elements, particle rotating display elements, etc., mounting of driving ICs such as thin displays and electronic paper Widely used as a method. Recently, a packaging method for obtaining BGA: ball grid array, micro ball grid array, and chip scale package through a film substrate for semiconductor mounting has been widely put into practical use.
The COF technology has many excellent features such as being easy to cope with the thinning and multi-pin circuit element package, and being able to adopt batch bonding for mounting semiconductor chips and the like. Have. In particular, batch bonding can significantly reduce the bonding time compared to wire bonding using a lead frame. For example, in the case of a 300-pin package, 45 to 60 seconds are required depending on the wire bonding method. The bonding operation can be completed in only about 1 to 2 seconds.

  A film substrate for semiconductor mounting usually has a structure in which a copper foil that functions as a conductive material is bonded to a long film made of an insulating material (for example, a polyimide film), and the copper foil is subjected to predetermined etching. Thus, a pad having a desired pattern is formed. These pad portions are subjected to gold, tin or solder plating, or gold plating at necessary portions in order to facilitate and surely perform a semiconductor chip bonding operation. In addition, protrusions called bumps are sometimes formed in the joint.

  One major factor that hinders the reliability of semiconductor circuit element packages produced using COF technology is cracking due to thermal strain that occurs as a result of repeated cooling and heating (conductive material, semiconductor chip, chip / conductor connection) Breaking or cracking of the part. This type of crack is caused by a difference in thermal expansion between copper, which is a conductive material, a semiconductor (silicon) chip, and a supporting base material. As another factor that hinders reliability, a crack due to strain generated as a result of expansion and contraction due to moisture absorption of the support film can be exemplified as well.

The largest application to which the COF technology is applied is mounting a driving IC for a flat display such as a liquid crystal display element. Such a driving IC is attached to two to four sides of the flat display. The so-called outer leads of the COF are connected to the electrodes drawn from the two to four sides of the flat display element. From the viewpoint of rationalization of the assembly process, it is preferable that this connection be made at a time, that is, the larger the work width and the number of leads on the outer lead side of the COF, the better. At present, the number of leads is increasing more than the work width is widened, and the distance between the lead wire width and the lead wire is becoming very narrow. When such narrowly spaced lead wires are arranged in a wide workpiece width, the lead terminal is displaced due to error accumulation, which is generally called an accumulated pitch problem. These characteristics are very important because errors are caused by differences in thermal expansion coefficient and humidity expansion coefficient.
In recent years, the chip area has been increased, and the number of input and output signal lines has increased at the same time. Therefore, the same problem has occurred on the pad side which is a connection portion with the semiconductor.

  Conventionally, a metallized polyimide film used for a so-called three-layer flexible printed wiring board in which a metal foil such as a copper foil or an aluminum foil is bonded to a polyimide film with an adhesive is known. This has the following problems considered to be caused by the adhesive used. First of all, there are drawbacks in that the dimensional accuracy is deteriorated due to thermal inferior performance than the film, and the electrical characteristics are deteriorated due to impurity ion contamination. In addition, there is a drawback that the workability such as the thickness of the adhesive layer and the through-hole drilling for both sides is lowered. Therefore, it can be said that there are many inconvenient points for reducing the size and weight.

On the other hand, a metal layer is formed on a polyimide film by vacuum deposition, sputtering, ion plating, copper plating, etc. without using an adhesive, for a two-layer flexible printed wiring board without a so-called thin film type adhesive layer Metallized polyimide films have been proposed.
For example, a flexible electric circuit carrier has been proposed in which a chromium-based ceramic vapor deposition layer, a copper or copper alloy vapor deposition layer, and a copper plating layer are sequentially provided on an insulating film (see Patent Document 1).
JP-A-4-329690

In addition, a metal-film laminate manufacturing method has been proposed in which a metal oxide by plasma is randomly arranged on a polymer film, and then a metal vapor deposition layer and a metal plating layer are provided (see Patent Document 2).
Further, a circuit material for providing a chromium / chromium oxide sputtering layer having a thickness of 25 to 150 Å on the electrically insulating support film and a copper sputtering layer having a thickness of less than 1 micron, and applying a photoresist composition to the copper layer. Has been proposed (see Patent Document 3).
JP-A-4-290742 Japanese Patent Application Laid-Open No. Sho 62-293689

In addition, part or all of the deposited metal is mixed in the film in the thickness direction facing inward from the surface of the film on one or both sides of the polyimide film containing 0.02 to 1% by mass of tin in the film. A flexible printed wiring comprising a first vapor-deposited metal layer having a thickness in a range of 10 to 300 angstroms including the mixed layer, and then a second vapor-deposited layer made of copper on the vapor-deposited layer. A substrate, wherein the first metal layer is preferably at least one selected from the group of chromium, a chromium alloy and a chromium compound, and the metal constituting the first vapor-deposited metal layer is nichrome whose chromium content is less than 20% by mass. A flexible printed wiring board is disclosed (see Patent Document 4).
JP-A-8-330728

As can be seen from these examples, the conventional thin film type metallized polyimide film is produced by first forming some base layer on the polyimide film and then forming copper as a good conductive material thereon. . There is no chemical bonding force between the metal layer, which is the conductive layer, and the polyimide film, which is the base material, and a micro base layer is microscopically applied to the surface of the base material, while copper is a metal / metal bond. Thus, the adhesive force is expressed through the underlayer.
When a non-metal or metal oxide is used for the underlayer, it is difficult to remove the underlayer by etching, and the metal oxide left between the lines due to the reducing action in the electroless plating process, etc. May be reduced and become a conductive metal foreign matter, resulting in poor insulation between wires. Further, chromium oxide often used as an underlayer is considered to be an unfavorable compound for environmental hygiene.

  When a metal other than copper is used for the underlayer, it becomes a problem whether the underlayer can be removed with a copper etching solution. If a metal having better corrosion resistance than copper is used, the removal of the underlying metal becomes insufficient, and the insulation between the lines may be lowered. In the case of a metal that is easier to etch than copper, the underlying portion is easily over-etched, and the effective adhesive strength of the conductor is likely to be reduced. Furthermore, even if the lowering of insulation due to the base metal itself is not a problem, the metal remaining during the subsequent electroless plating shows catalytic activity, and the plating metal may be deposited between the lines, resulting in a short circuit. is there. Furthermore, there is a concern that the base material remaining between the wirings may deteriorate the migration resistance between the wirings.

A base metal thin film and a copper thin film were formed on one surface of the polyimide film, and the other surface was constituted by a thin film with low oxygen permeability, and a circuit copper layer was provided on one or both surfaces of the polyimide film. Materials for flexible printed circuit boards have been proposed (see Patent Document 5).
The proposal was made from the viewpoint that the decrease in adhesive force is due to the oxidation of the interface between the metal and the polyimide film. However, all the materials with low oxygen permeability exemplified are brittle and have high flexibility. It is unsuitable for the required flexible printed wiring board.
JP-A-6-29634

From this point of view, in recent years, metalized polyimide films using nickel-chromium-based alloys as a base have attracted attention, and nickel-chromium-based alloy layers are used as base layers for general polyimide films, and further thickened with copper. There is an example of a metallized film (see, for example, Patent Document 6).
Nickel-chromium alloys are materials that have a relatively high resistance to oxidative embrittlement and can be expected to have an appropriate anchor effect. In the case of a nickel-chromium alloy, if the chromium content is relatively low, it can be easily removed with a copper etchant, resulting in poor insulation between wires due to abnormal deposition of electroless plating and the occurrence of migration. Hateful. However, if the chromium content is low, the hardness of the alloy is low, so that the anchoring effect is low, and furthermore, the oxidation resistance is lowered, so that it is difficult to obtain sufficient adhesion. Conversely, if the chromium content is large, the adhesive strength is improved, but the corrosion resistance of the alloy film is increased and the removal by etching becomes difficult, so that the insulation reliability between the wirings is lowered.
JP 2002-252257 A

  In recent years, the demand for high-density wiring in the semiconductor industry has advanced, and in the above-described advanced technology for semiconductor packaging film substrates for high-density wiring, the above-mentioned conventional technology is resistant to changes in temperature and humidity in the usage environment. Reliability such as sex cannot meet market demand.

  In view of such a situation, an advanced semiconductor substrate film substrate for high-density wiring has been made to increase reliability such as durability against changes in temperature and humidity in a use environment. Decrease in interfacial adhesion due to oxidative degradation of the formation is suppressed and durability is improved, and there is little change in the form of the polyimide film due to heat and humidity change, without reducing the etching property and plating resistance of the wiring circuit pattern, An object of the present invention is to provide a film substrate for semiconductor mounting which is excellent in migration resistance and as a result provides high reliability without lowering the adhesive strength even when exposed to long-time heating or wet heat. Another object of the present invention is to provide a film substrate for semiconductor mounting that has a copper foil adhesive strength sufficient to form fine lines and a sufficient insulation reliability between lines sufficient to realize fine line spacing.

That is, the present invention provides a metallized polyimide film having a nickel-chromium alloy sputter layer as an underlayer and a thickened metal layer , wherein the polyimide film has an aromatic diamine having a benzoxazole structure and an aromatic diamine. It consists of a polyimide obtained by reacting with tetracarboxylic acid anhydrides, the oxygen permeability of the polyimide film is 20 ml / m ² · day · atm or less, and the thermal expansion coefficient of the polyimide film is 0 to 11 ppm / ° C. It is the film substrate for semiconductor mounting characterized by using the metallized polyimide film which is this as a base material.

  The metallized polyimide film used as a substrate in the present invention is composed of a polyimide film having a specific structure having a low oxygen permeability and a low coefficient of thermal expansion, and further, the presence of the polyimide film by heat treatment in the production process. The strain generated during the manufacturing process of the metallized polyimide film is alleviated. Therefore, a decrease in interfacial adhesion due to oxidative deterioration of the underlayer is suppressed, and its durability is improved. In addition, since there is little change in the form of the polyimide film due to changes in heat and humidity, the adhesive strength decreases due to prolonged heating and exposure to wet heat without deteriorating the excellent electrical characteristics, etching characteristics of the wiring circuit pattern and plating resistance. Greatly improved. Furthermore, since it has excellent migration resistance, a film substrate for semiconductor mounting using the base material is useful as a flexible electronic circuit board material. In addition, even in a semiconductor package with high-density wiring that has been thinned, durability against changes in temperature and humidity in the usage environment of the semiconductor package is improved, and the reliability of the semiconductor is increased.

Hereinafter, embodiments of a film substrate for semiconductor mounting according to the present invention will be described in detail.
A schematic cross-sectional view of the metallized polyimide film of the present invention is shown in FIG. As shown in FIG. 1, the metallized polyimide film of the present invention comprises a base film 1-1 and a thick metal layer (1-3 conductive sputter layer and 1-4 thick metal layer (electroplating layer). In the meantime, a sputter layer 1-2 of nickel-chromium alloy is provided.

In the present invention, it is essential to use a polyimide film having an oxygen permeability of 20 ml / m ² · day · atm or less and a thermal linear expansion coefficient of 12 ppm / ° C. or less. Oxygen permeability is preferably from ^{14ml / m 2 · day · atm} , more preferably not more than ^{9ml / m 2 · day · atm} , and particularly preferably ^{7ml / m 2 · day · atm} .
In the metallized polyimide film, the adhesion between the metal foil and the film is governed by the anchor effect. In order for the anchor effect to be exhibited effectively, the interface needs to be robust. The greatest cause of the deterioration of the interface robustness is the oxidative deterioration of the metal surface. By using a material having a low oxygen permeability, the deterioration of the interface robustness can be minimized.

In the present invention, the thermal expansion coefficient of the polyimide film is preferably in the range of 0 to 11 ppm / ° C, more preferably in the range of 2 to 10 ppm / ° C, and still more preferably in the range of 3 to 9 ppm / ° C. By using a polyimide film having such characteristics, the above-described metallized polyimide film having excellent durability can be obtained.
If the coefficient of thermal linear expansion greatly exceeds this range, the dissociation from the coefficient of thermal linear expansion of the metal increases, and stress may be generated between the film and the metal surface when heated to cause a decrease in adhesive strength. In addition, since the region of about 12 to 18 is close to the thermal linear expansion coefficient of copper, which is a metal layer that is preferably used, it does not affect the film / metal adhesion. The dissociation from the thermal linear expansion coefficient of the element, particularly silicon or gallium athenite single crystal, is increased, and breakage of the junction is likely to occur during soldering or during a long-term temperature cycle. Furthermore, when the linear expansion coefficient is smaller than a predetermined range, the difference between both the metal and the semiconductor becomes large, so that the reliability is greatly lowered.

As described in claim 2, the water vapor permeability of the polyimide film in the present invention is preferably 3 ml / m ² · day · atm or more, more preferably 6 ml / m ² · day · atm or more, and 12 ml / m ^2. More preferably day · atm or more, particularly preferably 20 ml / m ² · day · atm or more.
Polyimide is a material that easily absorbs moisture due to its imide structure. Moisture absorption of the base film is a troublesome problem that may cause various problems in the process of releasing absorbed moisture when heated. Such moisture that has been absorbed becomes particularly problematic at the bonding interface between the film and the metal. A high water vapor transmission rate means that moisture absorbed near the interface can be effectively released. Such an effect becomes more prominent as the water vapor transmission rate is higher, and is further promoted as the water vapor transmission rate is higher than the oxygen transmission rate.

Control of the oxygen permeability and water vapor permeability of such a polyimide film can be realized, for example, by compounding a polyimide film with a material that can control gas permeability. As such a gas permeability control material, polyvinylidene chloride, polyvinyl alcohol, ethylene-polyvinyl alcohol copolymer or the like is used for a polymer material, and alumina-silica ceramic thin film, zinc sulfide thin film, SiO is used for an inorganic material. An example is a _2-X thin film. Examples of the composite form include multilayering, blending, dispersion, solid solution, blending, alloying, and the like.

  Since the polyimide film in the present invention needs to have a low thermal linear expansion coefficient as well as control of oxygen transmission rate and water vapor transmission rate, it is a preferred embodiment to use a polyimide having a specific composition described below. This method is recommended because it has a merit that durability can be improved as compared with the method in which the oxygen permeability is lowered by the above method.

In the case of polyimide, when an ether bond is introduced into the main chain, the flexibility of the molecule is increased and the free volume is increased, so that both oxygen permeability and water vapor permeability are increased. On the other hand, if the main chain has no bent structure such as an ether bond, and a component in which the planar structure of the aromatic ring is coplanar is introduced, a structure in which the aromatic ring is laminated by orientation is developed, rigidity is increased, oxygen Both the transmittance and water vapor permeability are low.
Even in such a rigid structure, the inventors have a polar structure (for example, benzoxazole structure) in the main chain, the nonpolar gas permeability is maintained in a low state, but a polar gas, for example, water vapor As a result, the inventors have found that the permeability increases, and a polyimide film having a low water vapor transmission rate and a high water vapor transmission rate has been obtained.
That is, the polyimide preferably used in the present invention specifically includes a polyimide obtained by condensation of a diamine having a benzoxazole structure and an aromatic tetracarboxylic acid anhydride. In general, a polyimide is a polyamic acid film obtained by applying a polyamic acid solution obtained by reacting a diamine and a tetracarboxylic anhydride in a solvent to a support and drying to form a polyamic acid film. The polyamic acid film is obtained by subjecting the polyamic acid film to a high temperature heat treatment in a state where it is peeled off from the base, and then performing a dehydration ring closure reaction.

Specific examples of the aromatic diamine having a benzoxazole structure in the present invention include the following.

を例示することができる。該ジアミンは、単独であっても二種以上を用いることも可能である。

Can be illustrated. Even if this diamine is individual, it is also possible to use 2 or more types.

  In the present invention, one or two or more diamines having no benzoxazole structure exemplified below may be used as long as they are 30 mol% or less of the total diamine. For example, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3 -Aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3 , 3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,4′-diamino Diphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3, '-Diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis [ 4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1, 1-bis [4- (4-aminophenoxy) phenyl Propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-amino) Phenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl] butane, 2- [4 -(4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) -3-methylphen Nyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4- Aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,4- Bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, bis [ 4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide Bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4 ′ -Bis (3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3, 4'-diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexaph Oropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] Ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3 -Aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-α, α -Dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis 4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [ 4- (4-Amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluorophenoxy) -α, α-dimethylbenzyl] Benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-cyanophenoxy) -α , Α-dimethylbenzyl] benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-diphenoxybenzophenone, 3,4 ′ Diamino-4,5′-diphenoxybenzophenone, 3,3′-diamino-4-phenoxybenzophenone, 4,4′-diamino-5-phenoxybenzophenone, 3,4′-diamino-4-phenoxybenzophenone, 3,4 '-Diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4'-diamino-4 , 5′-dibiphenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4′-diamino-4-biphenoxybenzophenone, 3,4 '-Diamino-5'-biphenoxybenzophenone, 1,3-bis (3-amino- 4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) benzene, 1,4-bis (4-amino) -5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,3-bis ( 4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- (4-amino-α, α-dimethylbenzyl) Phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring of the above aromatic diamine are halogen atoms or alkyl groups having 1 to 3 carbon atoms. Or an alkoxy group, a cyano group, or an alkyl group or an aromatic diamine substituted with an alkyl group or a halogenated alkyl group having 1 to 3 carbon atoms substituted with a halogen atom or an alkoxy group Is mentioned.

The tetracarboxylic acid anhydrides used in the present invention are aromatic tetracarboxylic acid anhydrides. Specific examples of the aromatic tetracarboxylic acid anhydrides include the following.

の使用が好ましい。これらのテトラカルボン酸二無水物は単独でも二種以上を用いることも可能である。

Is preferred. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

  In the present invention, one or two or more non-aromatic tetracarboxylic dianhydrides exemplified below may be used in combination as long as they are 30 mol% or less of the total tetracarboxylic dianhydrides. Examples of the tetracarboxylic anhydride used include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and cyclobutanetetracarboxylic acid. Dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene-2,3,5 , 6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-ethylcyclohexane -(1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane- 1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] Heptane-2,3,5,6 lacarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane-1- ( 2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2 , 3,5,6-tetracarboxylic dianhydride, Biciku [2.2.2] Octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride Such as anhydrides. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

In addition, maleic anhydride or the like can be used to seal the molecular ends of the linear polyimide or linear polyamic acid of the present invention with terminal groups having a carbon-carbon double bond. The amount of maleic anhydride used is 0.001 to 1.0 molar ratio per mole of aromatic diamine component.
The polar organic solvent used in the synthesis of the polyamic acid of the present invention is not particularly limited as long as it dissolves both the raw material monomer and the produced polyamic acid. For example, N-methyl-2-pyrrolidone, N- Acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, halogenated phenols, etc. These solvents can be used alone or in combination. The amount of the polar organic solvent used may be an amount sufficient to dissolve the charged monomer, usually 5 to 50% by mass, preferably 10 to 20% by mass. .

  The organic solvent solution of the polyamic acid used in the present invention preferably contains 5 to 40% by mass, more preferably 10 to 30% by mass of the solid content, and the viscosity is measured by a Brookfield viscometer. Those having a viscosity of 10 to 2000 Pa · s, preferably 100 to 1000 Pa · s are preferred because stable liquid feeding is possible. The polymerization reaction is continuously carried out in the temperature range of 0 to 80 ° C. for 10 minutes to 30 hours while stirring and / or mixing in an organic solvent. The polymerization reaction can be divided or the temperature can be increased or decreased as necessary. It doesn't matter. In this case, the order of addition of the two reactants is not particularly limited, but it is preferable to add aromatic tetracarboxylic anhydrides to the solution of aromatic diamines.

In the present invention, a ring-closing catalyst may be used. Specific examples of the ring-closing catalyst used in the present invention include aliphatic tertiary amines such as trimethylamine and triethylamine, and heterocyclic tertiary amines such as isoquinoline, pyridine and betapicoline. It is preferable to use at least one amine selected from tertiary amines.
Specific examples of the ring-closing catalyst used in the present invention include aliphatic tertiary amines such as trimethylamine and triethylamine, and heterocyclic tertiary amines such as isoquinoline, pyridine and betapicoline. It is preferable to use at least one amine selected from tertiary amines.

Vacuum defoaming during the polymerization reaction is an effective method for producing a high-quality polyamic acid organic solvent solution. Moreover, you may perform polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction.
Specific examples of the dehydrating agent used in the present invention include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride, Acetic anhydride and / or benzoic anhydride are preferred. The content of the ring-closing catalyst with respect to the polyamic acid is preferably in a range where the content (mol) of the ring-closing catalyst / the content (mol) of the polyamic acid is 0.5 to 8. In addition, the content of the dehydrating agent relative to the polyamic acid is preferably in a range where the content of dehydrating agent (mole) / polyamic acid content (mole) is 0.1 to 4. In this case, a gelation retarder such as acetylacetone may be used in combination.

  The polyimide film of the present invention is a polyamic acid film obtained by continuously extruding or applying a polyamic acid solution to a support in the form of a film, and then drying (also referred to as a green film) from the support, A typical method for producing a polyimide film from an organic solvent of a polyamic acid is produced by stretching, drying, and heat treatment. By casting on a support, forming into a film, and heating and drying on the support to form a self-supporting green film, the film is peeled off from the support, and further dried and heat-treated at a high temperature. Thermal ring closure method to imidize, slit organic solvent of polydoic acid impregnated with ring closure catalyst and dehydrating agent The film is cast from a mouthpiece onto a support and formed into a film, and after imidization is partially advanced on the support to obtain a self-supporting film, the film is peeled off from the support and dried by heating / The chemical ring closure method which imidizes and heat-processes is mentioned.

  The support in the present invention is a drum or belt-like rotating body used when forming a polyamic acid solution into a film. The polyamic acid solution is applied on a support and is self-supporting by heat drying. The surface of the support may be metal, plastic, glass, porcelain, etc., preferably metal, and more preferably SUS material that does not rust and has excellent corrosion resistance. Further, metal plating such as Cr, Ni, or Sn may be performed. The surface of the support in the present invention can be mirror-finished or processed into a satin finish if necessary.

The sputter layer 1-2 of nickel-chromium alloy provided on the surface of the base film has a thickness of 20 to 2000 mm, preferably 40 to 1000 mm, and more preferably 80 to 500 mm. If the thickness of the sputter layer 2 of nickel-chromium alloy is less than 20 mm, the adhesion is not sufficient, and if it exceeds 2000 mm, abnormal deposition of electroless tin plating applied to the circuit board becomes remarkable.
The thickness of the sputter layer of nickel-chromium alloy was measured by the fundamental parameter method (FP method) of fluorescent X-rays.
Further, the chromium content in the nickel-chromium alloy is desirably 1 to 10% by mass, more preferably 2 to 8% by mass, and still more preferably 3 to 6% by mass. If the chromium content is less than 1% by mass, the effect of improving the migration resistance is not present, and if it exceeds 10% by mass, the effect of improving the migration resistance is almost the same. There is a problem that the footsteps of copper increase.
The chromium content in the nickel-chromium alloy is measured by high frequency inductively coupled emission analysis.
The thickness of the thick metal layer provided on the nickel-chromium alloy sputter layer is preferably 1 to 12 μm, more preferably 1 to 9 μm, and even more preferably about 2 to 5 μm.
The thickness of the thick metal layer is measured by cross-sectional observation with a scanning electron microscope.

  The manufacturing method of the metallized polyimide film of this invention is demonstrated. In the present invention, as described in claim 7, after the surface of the polyimide film is subjected to plasma treatment, a nickel-chromium alloy is deposited to a thickness of 20 to 2000 mm by sputtering, and then the conductive layer is sputtered. It is a preferred embodiment to deposit by a vapor deposition method and / or an electroless plating method, and then further electroplating a thickened metal and performing a heat treatment at 200 to 350 ° C.

  First, the surface of the polyimide film is subjected to surface treatment by plasma treatment. Such plasma is inert gas plasma, and nitrogen gas, Ne, Ar, Kr, and Xe are used as the inert gas. There is no particular limitation on the method for generating plasma, and an inert gas may be introduced into the plasma generator to generate plasma. There is no particular limitation on the plasma treatment method, and a plasma treatment apparatus used for forming a metal layer on the base film may be used. The time required for the plasma treatment is not particularly limited, and is usually 1 second to 30 minutes, preferably 10 seconds to 10 minutes. There are no particular restrictions on the frequency and output of the plasma during the plasma processing, the gas pressure for generating the plasma, and the processing temperature as long as they can be handled by the plasma processing apparatus. The frequency is usually 13.56 MHz, the output is usually 50 W to 1000 W, the gas pressure is usually 0.01 Pa to 10 Pa, and the temperature is usually 20 ° C. to 250 ° C., preferably 20 ° C. to 180 ° C. If the output is too high, the substrate film surface may crack. Further, if the gas pressure is too high, the smoothness of the surface of the electrical insulating layer may be reduced. There is no particular limitation on the sputtering method, and DC bipolar sputtering, high-frequency sputtering, magnetron sputtering, counter target sputtering, ECR sputtering, bias sputtering, plasma controlled sputtering, multi-target sputtering, and the like can be used. Among these, direct current bipolar sputtering or high frequency sputtering is preferable. There are no particular restrictions on the output during sputtering processing, the gas pressure for generating plasma, and the processing temperature, so long as they can be handled by the sputtering apparatus. The output is usually 10 W to 1000 W, the gas pressure is usually 0.01 Pa to 10 Pa, and the temperature is usually 20 ° C. to 250 ° C., preferably 20 ° C. to 180 ° C. The film forming rate is 0.1 Å / second to 1000 Å / second, preferably 1 Å / second to 100 Å / second. If the film formation rate is too high, the formed metal film may be cracked. Moreover, when gas pressure is too high, there exists a possibility that adhesiveness may fall.

  Next, a nickel-chromium alloy is deposited on the surface-treated surface by sputtering to form a sputter layer of nickel-chromium alloy having a thickness of 20 to 2000 mm. The sputtering conditions are arbitrary. The sputter layer of nickel-chromium alloy may be a method using a nickel-chromium alloy target, a method of performing dual simultaneous sputtering, or a method of sputtering nickel and chromium independently and diffusing both in a later step. Can do.

  Next, a thick metal layer is formed. The thick metal layer is composed of a conductive layer and a thick layer, and the conductive layer may be formed by any one of a sputtering method, a vapor deposition method, and a wet electroless plating method, and preferably two or more. It is formed by combining methods. In the present invention, after a nickel-chromium alloy sputter layer, a copper layer of about 0.1 to 3 μm is first formed as a conductive layer by sputtering, vapor deposition, or electroless plating, and then thickened. As the layer, a method of further increasing the thickness of the copper layer by electroplating can be preferably used. As the metal of the thick metal layer, silver, copper, gold, platinum, rhodium, nickel, aluminum, iron, zinc, tin, brass, white copper, bronze, monel, tin lead solder, tin copper solder, tin silver A system solder or the like is used, but copper is a preferred embodiment in terms of a balance between performance and economy.

  Further, in the present invention, a method of forming a metal copper layer of about 0.1 to 3 μm by a vapor deposition method as a conductive layer after a sputter layer of nickel-chromium alloy can be particularly preferably used. Of course, the thickness of the metal copper layer can be increased by an electroplating method or the like thereafter. The film during vapor deposition is maintained at 100 ° C to 400 ° C, preferably 150 ° C to 300 ° C. By this method, the adhesion between the base layer and the copper layer becomes more robust. In such a process, it is presumed that a part of the base alloy and the metal copper to be deposited are diffused to each other, and a region having a composition gradient is formed at the interface. It is a preferable embodiment that copper is used for the metal as described above.

  Electroplating can be used for forming the copper layer that is preferably used as the thickening layer of the thick metal layer of the present invention. As the electroplating method, copper pyrophosphate plating or copper sulfate plating can be preferably used.

  In the present invention, it is a great feature that the composite of the polyimide film and metal obtained by the above method is further heat-treated at 200 to 350 ° C. 220-330 degreeC is preferable and 240-310 degreeC is more preferable. The heat treatment reduces the strain of the base film and the strain generated in the manufacturing process of the metallized polyimide film, and can more effectively express the effects of the present invention. Reliability can be improved. If it is less than 200 ° C., the effect of alleviating the strain becomes small. Conversely, if it exceeds 350 ° C., the polyimide film of the base material is deteriorated, which is not preferable.

The metallized polyimide film of the present invention thus obtained is coated with a photoresist on the copper layer side by an ordinary method, dried, and then exposed, developed, etched, and stripped of the photoresist by a step of removing the photoresist. Then, if necessary, solder resist coating, curing, and electroless tin plating are performed to obtain a circuit board.
Next, the manufacturing method of the film substrate for semiconductor mounting of the present invention, so-called COF tape will be described. The single-sided COF is produced by the following process.
(1) First, a metal foil (copper foil) is formed on a polyimide film slit to a predetermined width by the method described so far.
(2) Drill holes for alignment.
(3) The copper foil is patterned by a normal subtractive method.
(4) An etching resist is formed by a photo process or the like.
(5) Etching and stripping the resist.
(7) A solder resist is formed on a predetermined portion.
This is the single-sided COF tape. further,
(8) Mount an IC chip.
(9) The IC chip is sealed.
Through the above steps, a predetermined portion is cut out and mounted on the main board. FIG. 2 shows a schematic diagram of a method for producing single-sided COF.

The double-sided COF is produced by the following process.
(1) First, a metal foil (copper foil) is formed on both sides of a polyimide film slit to a predetermined width by the method described so far.
(2) Drill holes for alignment and through-hole connection.
(3) Through-hole plating (generally, electroless copper plating + electric thick plating).
(4) The copper foil is patterned by a normal subtractive method.
(5) An etching resist is formed by a photo process or the like.
(6) Etching and stripping the resist.
(7) A solder resist is formed on a predetermined portion.
This is the double-sided COF tape. further,
(8) Mount an IC chip.
(9) The IC chip is sealed.
Through the above steps, a predetermined portion is cut out and mounted on the main board. FIG. 3 shows a schematic diagram of a method for producing a double-sided COF of the present invention.

Hereinafter, the effectiveness of the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, the evaluation method of the physical property in the following examples is as follows.
1. Reduced viscosity of polyamic acid (ηsp / C)
A solution dissolved in N-methyl-2-pyrrolidone so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. using an Ubbelohde type viscosity tube.

2. Film thickness of polyimide film The thickness of the film was measured using a micrometer (manufactured by Fine Reef, Millitron 1245D).
3. Tensile modulus, tensile breaking strength and breaking elongation of polyimide film Test piece by cutting the dried film into a strip of 100 mm length and 10 mm width in the longitudinal direction (MD direction) and the width direction (TD direction), respectively. Then, using a tensile tester (manufactured by Shimadzu Autograph (R) model name AG-5000A), measurement was performed at a tensile speed of 50 mm / min and a distance between chucks of 40 mm to obtain tensile elastic modulus, tensile strength, and elongation at break .

4). Linear expansion coefficient (CTE) of polyimide film
The expansion / contraction rate was measured under the following conditions, and the range from 30 to 300 ° C. was divided at 15 ° C. intervals and obtained from the average value of the expansion / contraction rate / temperature of each divided range.
Device name: TMA4000S manufactured by MAC Science
Sample length; 20mm
Sample width: 2 mm
Temperature rise start temperature: 25 ° C
Temperature rising end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

5. Melting point of polyimide film, glass transition temperature A sample was subjected to DSC measurement under the following conditions, and a melting point (melting peak temperature Tpm) and a glass transition point (Tmg) were determined under the following measurement conditions in accordance with JIS K7121.
Device name: DSC3100S manufactured by MAC Science
Pan ： Aluminum pan (non-airtight)
Sample weight; 4mg
Temperature rising start temperature: 30 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

6). Thermal decomposition temperature of polyimide film The thermal decomposition temperature was defined by 5% weight loss by TGA measurement (thermobalance measurement) of a sufficiently dried sample under the following conditions.
Device name: TG-DTA2000S manufactured by MAC Science
Pan ： Aluminum pan (non-airtight)
Sample weight: 10mg
Temperature rising start temperature: 30 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

7). Oxygen permeability of polyimide film MOCON oxygen permeability measuring device OX-TRAN ten. Using fifty, measurement was performed at 23 ° C. and 65% RH by a method in accordance with JIS K7126 B method.
8). Water vapor transmission rate of polyimide film Using a water vapor transmission rate measuring device PERMATRAN-W 3/31 manufactured by MOCON, measurement was performed at 40 ° C. and 90% RH by a method in accordance with JIS K7129.

9. Sputtering layer thickness of nickel-chromium alloy Using the fundamental parameter method (FP method) of fluorescent X-rays, the thickness of the sputtered layer was measured by analysis software installed in a personal computer attached to the fluorescent X-ray analyzer. . In addition, for the purpose of improving the accuracy of the analysis value, one-point measurement for correcting the X-ray intensity with a nickel-chromium alloy thin film (composition ratio: nickel / chromium = 95/5, thickness: 2000 mm) whose composition and thickness are known. The method was used. The measurement conditions for fluorescent X-rays are shown below.
(Measurement condition)
Device name: Scanning X-ray fluorescence analyzer ZSX100e type X-ray tube manufactured by Rigaku Denki Kogyo Co., Ltd .; Rh (Rhodium)
X-ray output: 50 kV, 50 mA
Spectroscopic crystal; LiF
Line type used: Kα line Sample rotation: Yes (To average sample unevenness)

10. Chromium Content in Nickel-Chromium Alloy The sample polymer component was carbonized and incinerated at a temperature of 550 ° C., and the residue was heated and dissolved with dilute sulfuric acid, and the volume was adjusted after cooling. The chromium content in the solution was determined from a high frequency inductively coupled emission spectrometer. The measurement conditions for high frequency inductively coupled emission spectrometry are shown below.
(Measurement condition)
Device name: High frequency inductively coupled emission spectrometer CIROS120 manufactured by Rigaku Corporation
High frequency output: 1400W
Frequency: 27.12 MHz
Measurement emission line: 267.716 nm
11. Thickness of Thickened Metal Layer A metallized film embedded with an epoxy resin was subjected to chamfering and polishing using a microtome (Microtome JUNG RM2065 manufactured by Leica Corporation). Thereafter, the cross section of the sample after polishing was observed with a scanning electron microscope (S-4500, manufactured by Hitachi, Ltd.), and the thickness of the thick metal layer was measured. Note that the magnification of observation with a scanning electron microscope was appropriately adjusted according to the thickness of the thick metal layer.

12 Initial conductor adhesion of metallized polyimide film A 90-degree peel test was performed by a method according to JIS C5016.
13. Conductor adhesion after heating test of metallized polyimide film After leaving in a dry oven at 150 ° C. for 100 hours, a 90 ° peel test was performed by a method in accordance with JIS C5016.
14 Conductor adhesion after pressurization and humidification test of metalized polyimide film After processing for 100 hours under a PCT tester manufactured by Hirayama Seisakusho at 121 ° C and 2 atmospheres (saturated water vapor pressure atmosphere), a 90 ° peel test was conducted. The method was performed in accordance with C5016.
In addition, in copper foil 5 micrometers, since copper foil cutting frequently occurred and satisfactory evaluation could not be performed, only with respect to the items (7) to (9), the copper foil thickness was further increased to 35 μm by electroplating and evaluated. went.

15. Volume resistivity of metallized polyimide film It was performed by a method according to JIS C6481.
16. Surface resistance of metallized polyimide film It was performed by a method according to JIS C6481.
17. Migration resistance of metalized polyimide film Voltage (DC60V) is imprinted on a comb electrode with a pitch of 40μm and placed in a constant temperature and humidity chamber (FX412P type, manufactured by ETAC) at 85 ° C and 85% RH. The insulation resistance value was measured and recorded every 5 minutes as it was, and the time for the resistance value between the lines to reach 100 M ohms or less was measured for migration evaluation.

Example 1
<Polyimide polymer and film production example 1>
After the inside of a reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, 500 parts by weight of 5-amino-2- (p-aminophenyl) benzoxazole was charged. Next, 5000 parts by weight of N-methyl-2-pyrrolidone was added and completely dissolved, and then 485 parts by weight of pyromellitic dianhydride was added and stirred at a reaction temperature of 25 ° C. for 15 hours. A polyamic acid solution was obtained. Ηsp / C of this product was 2.0.
Subsequently, this polyamic acid solution was coated on a stainless steel belt so as to have a wet film thickness of 180 microns and dried at 80 ° C. for 60 minutes. The polyamic acid film that became self-supporting after drying was peeled from the stainless steel belt to obtain a green film. The obtained green film was passed through a continuous drying furnace, heated from 200 ° C. to 400 ° C. almost linearly in 20 minutes, cooled in 10 minutes, and a brown polyimide film (film 1) having a thickness of 25 μm was obtained. Obtained. Table 1 shows the characteristic values of the obtained polyimide film. In Table 1, Kapton (R) H is a polyimide film manufactured by Toray DuPont. Upilex S is a polyimide film manufactured by Ube Industries.

<Production method of metallized film>
The film 1 was cut into a square of 25 cm × 25 cm and fixed by being sandwiched between stainless steel frames having a direct 24 cm opening. Next, plasma treatment of the film surface was performed. The plasma treatment conditions were a xenon gas, a frequency of 13.56 MHz, an output of 100 W, a gas pressure of 0.8 Pa, a treatment temperature of 25 ° C., and a treatment time of 5 minutes. Next, a thickness of 13.56 MHz, an output of 400 W, a gas pressure of 0.8 Pa, a nickel-chromium (3 mass%) alloy target, and a thickness of 10 mm / sec by RF sputtering under a xenon atmosphere. A 50-mm nickel-chromium alloy coating (underlayer) was formed. Next, the temperature of the substrate was raised to 250 ° C., and copper was deposited at a rate of 100 Å / sec to form a copper thin film (conductive layer) having a thickness of 0.5 μm.
The obtained metallized film is re-fixed to a plastic frame, and a thick copper plating layer (thickening layer) with a thickness of 5 μm is formed using a copper sulfate plating bath, followed by heat treatment at 300 ° C. for 10 minutes. The intended metallized polyimide film was obtained.
Using the obtained metallized polyimide film, photoresist: FR-200, manufactured by Shipley Co., Ltd. was applied and dried, then contacted and exposed with a glass photomask, and further developed with a 1.2% by mass aqueous KOH solution. Next, etching is performed with a cupric chloride etching line containing HCl and hydrogen peroxide at 40 ° C. and a spray pressure of ² kgf / cm ² to form a test pattern necessary for an evaluation test described later, and then a thickness of 0.5 μm. Then, electroless tin plating was performed. Thereafter, annealing was performed at 125 ° C. for 1 hour.
Test evaluation was performed using the obtained test pattern. The results are shown in Table 2.

(Examples 2 to 4)
The same operation as in Example 1 was performed except that the thickness of the nickel-chromium alloy layer was changed, and evaluation was performed. The results are shown in Table 2.
(Examples 5 to 8)
<Polyimide polymer and film production example 2>
A polyamic acid solution was obtained in the same manner as in Example 1 (Film 1) except that 653 parts by weight of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was used as the tetracarboxylic dianhydride. Ηsp / C of this was 1.5, and a brown polyimide film (film 2) having a thickness of 25 μm was obtained in the same manner as in Example 1 (film 1). Table 1 shows the characteristic values of the obtained polyimide film.
<Production method of metallized film>
Except having changed the base film into the said film 2, it operated similarly to Examples 1-4 and evaluated. The results are shown in Table 3.
(Examples 9 and 10)
Using the polyimide film 1, the chromium content of the nickel-chromium alloy was changed, and the other operations were performed and evaluated in the same manner as in Example 1. The results are shown in Table 4.
(Examples 11 and 12)
Using the film 2, the chromium content of the nickel-chromium alloy was changed, and other operations were performed and evaluated in the same manner as in Example 5. The results are shown in Table 4.

(Comparative Examples 1-4)
Operations were evaluated in the same manner as in Examples 1 to 4 except that the base film was changed to Kapton (R) H manufactured by Toray DuPont. The results are shown in Table 5.
(Comparative Examples 5 to 8)
The same operation as in Examples 1 to 4 was performed, except that the base film was changed to Upilex (R) S manufactured by Ube Industries, Ltd., and evaluated. The results are shown in Table 6.
(Comparative Examples 9-12)
The film 1 was used as the base film, and the film thickness of the nickel-chromium layer and the chromium content were changed, and the evaluation was performed in the same manner. The results are shown in Table 7.

  The film substrates for semiconductor mounting obtained in Examples 1 to 12 are excellent in adhesive strength between the conductor and the base film, particularly after heat treatment and after the humidification heating test, and abnormal deposition of electroless tin plating In addition, there is no problem in migration resistance, and the insulation reliability is excellent and the quality is high. On the other hand, the film substrates for semiconductor mounting obtained in Comparative Examples 1 to 8 have low adhesive strength between the conductor and the base film after the humidification heating test. The film substrates for semiconductor mounting obtained in Comparative Examples 9 to 12 tend to cause abnormal deposition of electroless tin plating, or have poor migration resistance and poor insulation reliability.

  As described above, the film substrate for semiconductor mounting according to the present invention is a metallized polyimide film used as a base material, and a polyimide film having a specific structure with a low oxygen permeability and a low coefficient of thermal expansion is used as a constituent material. Furthermore, the distortion which the polyimide film has and the distortion which arises in the manufacture process of a metallized polyimide film are relieved by the heat treatment in the manufacturing process. Therefore, a decrease in interfacial adhesion due to oxidative deterioration of the underlayer is suppressed, and its durability is improved. In addition, since there is little change in the form of the polyimide film due to changes in heat and humidity, the adhesive strength decreases due to prolonged heating and exposure to wet heat without deteriorating the excellent electrical characteristics, etching characteristics of the wiring circuit pattern and plating resistance. Greatly improved. Furthermore, since it has excellent migration resistance, a film substrate for semiconductor mounting using the base material is useful as a flexible electronic circuit board material. Further, even in a thinned semiconductor package with high-density wiring, durability against changes in temperature and humidity in the usage environment of the semiconductor package is improved, and the reliability of the semiconductor is increased.

It is a schematic sectional drawing of the metallized polyimide film used for this invention. It is sectional drawing explaining the single-sided COF manufacturing method of this invention. It is sectional drawing explaining the double-sided COF manufacturing method of this invention.

Explanation of symbols

1-1. Polyimide film 1-2. Sputtered nickel-chromium layer (underlayer)
1-3. Thick metal layer (conductive layer)
1-4. Thickened metal layer (thickened layer)
1. 1. Base film Copper foil Through-hole plated copper 4. 4. Etching resist Solder resist IC chip 7. Sealing material

Claims (6)

A metallized polyimide film having a nickel-chromium alloy sputter layer as an underlayer and a thickened metal layer , wherein the polyimide film has a benzoxazole structure and an aromatic tetracarboxylic acid anhydride A metallized polyimide comprising a polyimide obtained by reacting with a polyimide, wherein the polyimide film has an oxygen permeability of 20 ml / m ² · day · atm or less and a thermal expansion coefficient of the polyimide film of 0 to 11 ppm / ° C. A film substrate for semiconductor mounting, characterized by using a film as a substrate. The film substrate for semiconductor mounting according to claim 1, wherein the polyimide film has a water vapor transmission rate of 3 ml / m ² · day · atm or more.   The film substrate for semiconductor mounting according to claim 1 or 2, wherein the nickel-chromium alloy sputter layer has a thickness of 20 to 2000 mm.   The film substrate for semiconductor mounting according to any one of claims 1 to 3, wherein the chromium content of the sputter layer of the nickel-chromium alloy is 1 to 10% by mass.   The film substrate for semiconductor mounting according to any one of claims 1 to 4, wherein the thickness of the thickened metal layer is 1 to 12 µm.   After the polyimide film surface is plasma treated, a nickel-chromium alloy is deposited by sputtering to a thickness of 20 to 2000 mm, and then a conductive layer is deposited by sputtering and / or vapor deposition and / or electroless plating. The metallized polyimide film obtained by carrying out the electroplating of the thickening metal after that, and also performing the heat processing of 200-350 degreeC further is used as a base material. Film substrate for semiconductor mounting.

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