JP2004292700A - Semiconductor mounting film substrate and semiconductor package using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor mounting polyimide film which is free of elongation, warpage, or curling during the step of processing a TAB tape or a flexible printed board and, further, is high in temperature resistance during the step of reflow soldering for semiconductor mounting. <P>SOLUTION: The semiconductor mounting polyimide film has a mean coefficient of linear expansion of 15-30 ppm at 50-200°C, and has a difference in refractivity Δn of ≤0.17 in the film between the direction of the average orientation axis and the direction of thickness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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【表２】

【００５９】
【表３】

【００６０】
【発明の効果】
本発明により、様々な電子機器の軽量、小型化に伴い、絶縁材料として好適に使用できるポリイミドフィルムを提供でき、フレキシブルプリント基板やＴＡＢ（Ｔａｐｅ Ａｕｔｏｍａｔｅｄ Ｂｏｎｄｉｎｇ）方式に用いられるテープの反り特性を改善することができる。
【図面の簡単な説明】
【図１】膜面内の平均配向軸方向と厚み方向と屈折率の差Δｎの測定方法を表した図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyimide film used as a semiconductor mounting substrate typified by a ball grid array (BGA) manufactured by a tape automated bonding (TAB) method or the like and an interposer of a chip size package (CSP). The present invention relates to a used film carrier tape (FC tape) and a semiconductor package obtained by using the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as a method for mounting a semiconductor integrated circuit, a method using a connection substrate in which a circuit pattern is formed on an organic insulating film such as glass epoxy, liquid crystal polyester, or polyimide has been increasing. A representative example of such a system is a tape carrier package (TCP) based on a TAB system. In such a TAB method, an FC tape having a three-layer structure of a protective layer, an adhesive layer, and an organic insulating film layer (base film layer) is generally used, and an LSI is formed on a TAB tape obtained by processing the FC tape. The processing steps up to mounting are performed as follows.
[0003]
That is, the TAB tape processing steps include: (1) a step of forming sprocket holes, device holes, and via holes by punching; (2) a step of removing a protective layer and laminating a copper foil, followed by a step of curing an adhesive; (4) A TAB tape is manufactured through an arrangement pattern forming step (resist coating, copper etching, resist stripping), and (4) a plating step.
[0004]
An IC is connected on the TAB tape by gang bonding or wire bonding according to the use and use of the package. Thereafter, if necessary, a semiconductor package is completed through steps such as resin sealing and solder ball formation.
[0005]
In these processing steps, warping or curling of a flexible copper clad laminate (FCCL) or TAB tape is one of the causes of mounting failure. The warp or curl causes a formation failure of a placement pattern, a bonding failure of a semiconductor chip, or the like in a process requiring dimensional accuracy, such as formation of an arrangement pattern, inner lead bonding, or outer lead bonding. Also, since the actual process is performed on a reel-to-reel basis and tension is applied in the longitudinal direction of the TAB tape, warpage and curl in the longitudinal direction can be corrected, but warpage and curl in the tape width direction must be corrected. Can not.
[0006]
In order not to cause the above-mentioned inconveniences, specifically, in processing a TAB tape and a flexible printed wiring board, a base film having a designed coefficient of linear expansion and a coefficient of hygroscopic expansion is required.
[0007]
In recent years, when mounting the semiconductor package obtained as described above on a printed circuit board such as reflowing a solder ball formed on the lower surface of the interposer and mounting it on the printed circuit board, a method called a surface mounting method is mainly used. It has become. At this time, when an existing resin film is used, the FCCL swells at the time of solder reflow, a so-called popcorn phenomenon occurs, and there is a problem that the yield decreases.
[0008]
For example, Patent Literature 1 discloses a technique for reducing a defective rate at the time of soldering a semiconductor package by using an organic insulating film having a specified water vapor transmission rate. However, this patent document does not solve an important problem in the semiconductor package manufacturing process, that is, the problem of FCCL warpage.
[0009]
Further, Patent Literature 2 discloses a technique for reducing a popcorn phenomenon at the time of chip mounting by using a polyimide film having a specified water absorption rate and water vapor transmission rate. However, even in this patent document, an important problem in the semiconductor package manufacturing process, that is, the problem of FCCL warpage has not been solved.
[0010]
[Patent Document 1] JP-A-11-233567
[0011]
[Patent Document 2] JP-A-2001-244380
[0012]
[Problems to be solved by the invention]
In view of the above situation, the present inventors have conducted intensive studies, and as a result, in the process of forming a TAB tape or a flexible printed board, no elongation occurs, no warping or curling, and further, in a semiconductor mounting process. The present invention has been accomplished with respect to a polyimide film for semiconductor mounting having a high heat resistance temperature during solder reflow.
[0013]
[Means for Solving the Problems]
The present invention is characterized in that the average linear expansion coefficient at 50 to 200 ° C. is 20 to 30 ppm, and the difference Δn between the average orientation axis direction in the film plane and the refractive index in the thickness direction is 0.17 or less. It relates to a polyimide film.
Furthermore, the present invention relates to the polyimide film for semiconductor mounting according to claim 1, wherein Δn is 0.15 or less.
Further, the present invention relates to the polyimide film for semiconductor mounting, wherein the density is 1.46 g / cc or less.
[0014]
Further, the present invention relates to the polyimide film for semiconductor mounting, wherein the loop stiffness is 3 to 50 g / cm.
[0015]
Also, the present invention relates to 20-70 mol% of p-phenylenediamine per 100 mol% of diamine component and 20-80 mol% of 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dicarboxylic acid per 100 mol% of acid component. 4. The polyimide film for semiconductor mounting according to claim 1, wherein an anhydride is used as an essential component.
[0016]
The present invention also relates to a polyimide film with an adhesive, comprising at least the resin film, the adhesive layer, and the protective film.
[0017]
Further, the present invention relates to a semiconductor package obtained by using the polyimide film with an adhesive.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the polyimide film of the present invention will be described based on an example of the embodiment.
[0019]
As a method for producing the polyamic acid used in the present invention, any known method can be used.Usually, an aromatic dianhydride and an aromatic diamine are dissolved in substantially equimolar amounts in an organic solvent, It is manufactured by stirring the obtained polyamic acid organic solvent solution under controlled temperature conditions until the polymerization of the acid dianhydride and the diamine is completed. These polyamic acid solutions are usually obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. When the concentration is within this range, an appropriate molecular weight and solution viscosity are obtained.
[0020]
As the polymerization method, any known method can be used, and particularly preferred polymerization methods include the following methods. That is,
1) A method in which an aromatic diamine is dissolved in an organic polar solvent, and a substantially equimolar amount of an aromatic tetracarboxylic dianhydride is reacted to carry out polymerization.
2) An aromatic tetracarboxylic dianhydride and an excessively small amount of an aromatic diamine compound are reacted in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both terminals. Subsequently, a method of polymerizing using an aromatic diamine compound so that the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in all steps.
3) An aromatic tetracarboxylic dianhydride is reacted with an excess molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having amino groups at both terminals. Subsequently, after the aromatic diamine compound is additionally added, an aromatic tetracarboxylic dianhydride and an aromatic diamine compound are used in substantially all equimolar amounts in all the steps using the aromatic tetracarboxylic dianhydride. How to polymerize.
4) A method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized with an aromatic diamine compound so as to be substantially equimolar.
5) A method in which a mixture of substantially equimolar aromatic tetracarboxylic dianhydride and aromatic diamine is reacted in an organic polar solvent to carry out polymerization.
And so on.
[0021]
In these methods, from the viewpoint of controlling the linear expansion coefficient to 20 to 30 ppm and controlling the polymerization reaction relatively easily, all the aromatic diamine components used in all the steps are dissolved in an organic solvent, and then substantially dissolved. It is preferable to use a method in which an aromatic tetracarboxylic acid is added so as to be equimolar to carry out a polymerization reaction.
[0022]
Here, the materials used for the polyamic acid composition according to the present invention will be described.
[0023]
Suitable acid anhydrides that can be used in the present invention include pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. Anhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic Acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) Propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-di Carboxyphenyl) meth Dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, p-phenylenebis (trimellitic acid monoanhydride) Ester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and their analogs, either alone or in a mixture at any ratio Can be preferably used.
[0024]
Among these acid dianhydrides, use of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and / or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is particularly preferred. preferable. The preferred amount of 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride and / or 3,3', 4,4'-biphenyltetracarboxylic dianhydride is based on the total acid dianhydride. And 20 to 60 mol%, preferably 25 to 60 mol%, and more preferably 25 to 55%. If the amount of 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride and / or 3,3', 4,4'-biphenyltetracarboxylic dianhydride is below this range, the linear expansion coefficient and It tends to be difficult to balance the loop stiffness, and if it exceeds this range, the coefficient of hygroscopic expansion tends to be too large and the warpage tends to be large. Further, when the value exceeds this range, the popcorn phenomenon tends to easily occur when the semiconductor is mounted.
[0025]
Further, p-phenylenebis (trimellitic acid monoester anhydride), ethylene bis (trimellitic acid monoester anhydride), bisphenol A bis (trimellitic acid monoester anhydride) and the like are also preferable. It is also preferable to use a combination of different ester dianhydrides. Among them, p-phenylenebis (trimellitic acid monoester anhydride) is also used from the viewpoint of improving the mechanical strength, the coefficient of hygroscopic expansion and the thermal behavior of polyimide. preferable. The preferred amount of p-phenylenebis (trimellitic acid monoester anhydride) used is 10 to 60 mol%, preferably 20 to 55 mol%, more preferably 25 to 50 mol%, based on the total acid dianhydride. If the amount of p-phenylenebis (trimellitic acid monoester anhydride) falls below this range, the effect of improving the modulus of elasticity and the coefficient of hygroscopic expansion tends to be too small, and if it is greater than this range, the flexibility of the film is reduced. It tends to be smaller.
[0026]
Further, in the present invention, when another acid dianhydride is used in combination, pyromellitic dianhydride is preferably used. The preferred use amount of pyromellitic dianhydride is 10 to 60 mol%, more preferably 10 to 50 mol%, and particularly preferably 10 to 45 mol%.
Suitable diamines that can be used in the polyimide precursor polyamic acid composition according to the present invention include 4,4′-oxydianiline, p-phenylenediamine, 4,4′-diaminodiphenylpropane, and 4,4′-diamino. Diphenylmethane, benzidine, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 4,4′-oxydianiline, 3, 3'-oxydianiline, 3,4'-oxydianiline, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethyl Phosphine oxide, 4,4′-diaminodiphenyl N-methylamine, , 4'-diamino diphenyl N- phenylamine, 1,4-diaminobenzene (p- phenylene diamine), 1,3-diaminobenzene, 1,2-diaminobenzene, and their analogs thereof. These diamine compounds can be used alone or in an arbitrary mixing ratio. Among these diamines, 4,4′-oxydianiline and p-phenylenediamine are molar ratios of 1/9 to 9/1, preferably It is preferable to use in the range of 1/7 to 7/1, and more preferably in the range of 1/4 to 4/1, since a polyimide film having an excellent balance of various properties can be obtained.
[0027]
The polyimide film used in the present invention is obtained by appropriately determining the type and blending ratio of the aromatic dianhydride and the aromatic diamine so as to obtain a film having desired properties within the above range. Can be.
As a preferable solvent for synthesizing the polyamic acid, any solvent can be used as long as it can dissolve the polyamic acid, but an amide solvent, that is, N, N-dimethylformamide, N, N-dimethylacetamide, N- Examples thereof include methyl-2-pyrrolidone, and N, N-dimethylformamide and N, N-dimethylacetamide are particularly preferably used.
[0028]
Further, a filler can be added for the purpose of improving various properties of the film such as slidability, thermal conductivity, conductivity, corona resistance, and loop stiffness. Any filler may be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.
The particle size of the filler is not particularly limited because it is determined by the properties of the film to be modified and the type of filler to be added, but the average particle size is generally 0.05 to 100 μm, preferably 0.1 to 100 μm. To 75 μm, more preferably 0.1 to 50 μm, particularly preferably 0.1 to 25 μm. If the particle size is below this range, the modifying effect is less likely to be exhibited, and if it exceeds this range, the surface properties may be significantly impaired, or the mechanical properties may be significantly reduced. Also, the number of fillers to be added is not particularly limited because it is determined by the film properties to be modified, the filler particle diameter, and the like. Generally, the filler is added in an amount of 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight, based on 100 parts by weight of the polyimide. If the amount of the filler is less than this range, the effect of modifying by the filler is unlikely to appear, and if it exceeds this range, the mechanical properties of the film may be significantly impaired. The addition of filler
(1) Method of adding to a polymerization reaction solution before or during polymerization
(1) After completion of polymerization, kneading the filler using three rolls
{Circle around (1)} A method in which a dispersion liquid containing a filler is prepared and mixed with a polyamic acid organic solvent solution
Any method may be used, but a method of mixing a dispersion containing a filler with a polyamic acid solution, particularly a method of mixing immediately before film formation is preferable because contamination by a filler in a production line is minimized. When preparing a dispersion containing a filler, it is preferable to use the same solvent as the polymerization solvent for the polyamic acid. Further, in order to disperse the filler well and to stabilize the dispersion state, a dispersant, a thickener and the like can be used within a range that does not affect the physical properties of the film.
[0029]
As a method for producing a polyimide film from these polyamic acid solutions, a conventionally known method can be used. This method includes a thermal imidation method and a chemical imidization method, and the film may be produced using either method, but the imidation by the chemical imidation method is preferably used in the present invention. There is a tendency that a polyimide film for semiconductor mounting having various characteristics is easily obtained.
[0030]
In the present invention, a particularly preferred process for producing a polyimide film includes:
a) reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride in an organic solvent to obtain a polyamic acid solution;
b) casting a film-forming dope containing the polyamic acid solution on a support,
c) after heating on the support, peeling off the gel film from the support;
d) further heating to imidize the remaining amic acid and drying.
It is preferable to include
[0031]
Taking a preferred embodiment of the present invention as an example, a process for producing a polyimide film will be described.
Chemical curing method, a polyamic acid organic solvent solution, a dehydrating agent represented by an acid anhydride such as acetic anhydride, and an imidation catalyst represented by a tertiary amine such as isoquinoline, β-picoline, and pyridine. Is a method of acting. A thermal imidation method may be used in combination with the chemical imidization method. Heating conditions can vary depending on the type of polyamic acid, film thickness, and the like.
The dehydrating agent and the imidization catalyst are mixed at low temperature into the polyamic acid solution to obtain a film forming dope. Subsequently, the film-forming dope is cast into a film on a support such as a glass plate, an aluminum foil, an endless stainless steel belt, or a stainless steel drum, and the temperature of the support is set to 80 ° C to 200 ° C, preferably 100 ° C to 180 ° C. The dehydrating agent and the imidization catalyst are activated by heating in the region to partially cure and / or dry, and then peeled from the support to obtain a polyamic acid film (hereinafter, referred to as a gel film).
[0032]
The preferred amount of the dehydrating agent is 1 to 5 mol, preferably 1.5 to 4 mol, per 1 mol of the amide acid unit in the polyamic acid.
The preferred amount of the imidation catalyst is 0.2 to 3 mol, preferably 0.3 to 2 mol.
[0033]
If the dehydrating agent and the imidization catalyst are below the above ranges, the chemical imidization is insufficient, and the material may be broken during firing or the mechanical strength may be reduced. On the other hand, when these amounts exceed the above range, imidization proceeds too quickly, and it may be difficult to cast into a film, which is not preferable.
[0034]
The edge of the gel film is fixed and dried while avoiding shrinkage during curing, water, residual solvent, residual converting agent and catalyst are removed, and the remaining amic acid is completely imidized to obtain the present invention. A polyimide film is obtained.
[0035]
At this time, it is preferable to finally heat at a temperature of 400 to 600 ° C. for 5 to 400 seconds. If the temperature is higher than this temperature and / or the time is longer, the film may be thermally degraded to cause a problem. Conversely, if the temperature is lower than this temperature and / or the time is short, the predetermined effect may not be exhibited.
[0036]
Typically, among the polyimide films obtained as described above, a polyimide film suitable for a semiconductor mounting application of the present invention has the following characteristics.
(1) The average coefficient of linear expansion at 50 to 200 ° C is 20 to 30 ppm
{Circle around (1)} The difference Δn between the average orientation axis direction and the thickness direction in the film plane is 0.17 or less.
The preferred value of the average linear expansion coefficient, other properties that the polyimide film has, for example, because it can fluctuate due to the moisture expansion coefficient, it can not be clearly defined, but when using a polyimide film having a linear expansion coefficient in the above range. A TAB tape having generally good warpage characteristics can be obtained. For example, in the case of a polyimide film having a moisture expansion coefficient of about 5 to 10 ppm, the average linear expansion coefficient is preferably 15 to 30 ppm, more preferably 20 to 27 ppm, and particularly preferably 21 to 25 ppm. The tendency is that the larger the coefficient of hygroscopic expansion becomes, the larger the preferable average linear expansion coefficient becomes, and the smaller the coefficient of hygroscopic expansion becomes, the smaller the preferable average linear expansion coefficient becomes. The average linear expansion coefficient is preferably within the above range in all directions in the film plane. When the above range is not satisfied in all directions in the film plane, the warpage and the curl tend to increase.
[0037]
In the present invention, the difference Δn between the average orientation axis direction and the thickness direction in the film plane is preferably 0.10 to 0.17, more preferably 0.11 to 0.16, and particularly preferably 0.1 to 0.16. 12 to 0.15. Although the reason is not clear, it has been found that when a polyimide film having a refractive index difference Δn in the above range is used as a semiconductor mounting substrate, the popcorn phenomenon, which is one of the problems, that is, the solder heat resistance is improved. . When the thermal conductivity exceeds the above range, the solder heat resistance tends to be inferior, that is, the popcorn phenomenon easily occurs. When the thermal conductivity is below the above range, the coefficient of linear expansion tends to deviate from a suitable range. If the ratio is below the above range, the elastic modulus tends to decrease, and in the TAB tape in the middle of the semiconductor mounting process, the warpage with the wiring pattern of the conductive layer inward in the width direction is likely to occur, and Time alignment is difficult, and the yield is likely to be reduced.
[0038]
Further, the density of the polyimide film used in the present invention is preferably 1.46 g / cc or less, particularly preferably 1.45 g / cc or less. If the density exceeds this range, the solder heat resistance tends to be inferior, that is, the popcorn phenomenon tends to occur.
Furthermore, the loop stiffness of the polyimide film suitably used in the present invention is 3 to 50 g / cm or more, preferably 4 to 40 g / cm, more preferably 4.5 to 40 g / cm, and particularly preferably 5.0 to 50 g / cm. 30 g / cm. If the loop stiffness is below this range, the warpage tends to deteriorate, and if it exceeds this range, the solder heat resistance tends to deteriorate.
[0039]
The polyimide film suitably used in the present invention preferably further has the following various properties.
(1) The water absorption is 3% or less, preferably 2.5% or less, particularly preferably 2.3% or less. (1) The elastic modulus is 4.5 to 8.0 GPa, preferably 5.0 to 7.5 GPa.
(1) The coefficient of hygroscopic expansion is 15 ppm or less, preferably 13 ppm or less, particularly preferably 12 ppm or less.
{Circle around (1)} The thickness is 10 to 125 μm, preferably 20 to 100 μm, more preferably 25 to 80 μm, and particularly preferably 40 to 65 μm.
If these properties deviate from the preferred ranges described above, undesired results may be obtained in terms of warpage properties, solder heat resistance and punching properties in the process of TAB tape processing.
[0040]
Furthermore, when a TAB tape is prepared using the polyimide film thus obtained, the adhesive is completely cured, and after humidifying for 100 hours in an environment of 23 ° C. and 60% RH (etching of conductive layer). No), the amount of warpage is such that the warpage on the inside of the adhesive surface is plus and the warpage on the outside of the adhesive surface is minus, preferably 0.5 mm or less, more preferably 0 mm or less, particularly preferably -0.5 mm or less. And the amount of warpage after completely removing the conductive layer by etching and controlling the humidity for 100 hours in an environment of 23 ° C. and 60% RH is preferably 3.0 mm or less, more preferably 2.5 mm or less. Particularly preferably, it is 2.0 mm or less. When the amount of warpage after the conductive layer is attached and after the conductive layer is fully etched satisfies these ranges at the same time, it is possible to eliminate defects caused by warpage in the processing and mounting steps.
[0041]
Furthermore, the solder heat resistance temperature of such a TAB tape is preferably 260 ° C. or higher, more preferably 265 ° C. or higher, and particularly preferably 270 ° C. or higher. If the soldering heat-resistant temperature falls below this range, an undesired phenomenon such as a popcorn phenomenon occurs in the solder reflow process at the time of semiconductor mounting, which is one of the causes of a decrease in yield.
[0042]
The adhesive used for the polyimide film with the adhesive, which is another object of the present invention, is usually in a semi-cured state, and after a conductive layer such as a copper foil is formed, it is completely cured by a method such as heating. The thickness of the adhesive layer is 3 to 50 μm, preferably 5 to 40 μm, particularly preferably 5 to 30 μm. If the thickness is below this range, the adhesion between the conductive layer and the base film tends to be small, and if it is above this, the wiring pattern tends to be difficult to be fine.
[0043]
The chemical structure of the adhesive is not particularly limited, but contains at least one resin selected from a polyamide resin, an epoxy resin, a phenol resin, a polyimide resin, a polyamideimide resin, a maleimide resin, and the like. And a thermoplastic resin are preferably used in combination.
[0044]
As the epoxy resin, any epoxy resin having two or more epoxy groups in one molecule may be used. However, bisphenol A, bisphenol F, bisphenol S, dihydroxynaphthalene, diglycidyl ether, dihydroxynaphthalene, dihydroxynaphthalene, Cyclopentadiene diphenol, epoxidized phenol novolak, epoxidized cresol novolak and the like.
[0045]
As the phenol resin, any known phenol resin such as a novolak type or a resol type may be used. Examples thereof include cyclic alkyl-modified phenols such as phenol, cresol, alkyl-substituted phenol, and dicyclopentadiene, and resins composed of polyfunctional phenols such as bisphenol A, bisphenol F, bisphenol S, resorcinol, and pyrogallol.
[0046]
As the maleimide resin, it is preferable to use one having two or more functionalities. For example, bisimide represented by N, N ′-(4,4′-diphenylmethane) bismaleimide, N, N′-p-phenylenebismaleimide and the like are preferable. Maleimide and the like.
[0047]
Further, a curing agent and / or a curing accelerator of the thermosetting resin may be added to the adhesive layer used in the present invention. For example, any known compounds such as an amine complex of boron trifluoride, an imidazole derivative, an organic acid anhydride such as phthalic anhydride and trimellitic anhydride, dicyandiamide, triphenylphosphine, and diazabicycloundecene may be used. When these curing agents and / or effect promoters are added, 0.1 to 15% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.2 to 8% by weight, based on 100% by weight of the adhesive layer. It is preferable to add at a ratio of weight%.
[0048]
Resins such as polyimide, polyamide imide, and polyamide as thermoplastic resin components that can be contained in the adhesive layer include a softening temperature of the adhesive layer, an adhesive strength in a semi-cured state, an adhesive strength during curing, flexibility, and low water absorption. It can be added for the purpose of expressing the property. The preferable addition amount of such a thermoplastic resin component is 25 to 60% by weight, further 30 to 55% by weight, particularly 30 to 50% by weight based on 100% by weight of the adhesive layer.
[0049]
In addition, these thermoplastic resins have in their molecules amino, carboxyl, epoxy, hydroxyl, methylol, isocyanate, vinyl, silanol groups, and other functional groups that can react with phenolic or epoxy resins. Is also good.
[0050]
As the adhesive used in the present invention, it is preferable to use an adhesive having a high modulus of elasticity at high temperature after complete curing for the purpose of avoiding sinking of the conductive layer during wire bonding. For example, it is preferable to use one having a storage modulus at 150 ° C. of 50 to 300 MPa, more preferably 60 to 250 MPa, and particularly preferably 70 to 220 MPa. If the storage elastic modulus is below this range, sinking of the conductive layer tends to occur during wire bonding, and if it exceeds this range, the warpage during full etching of the conductive layer tends to increase.
[0051]
Further, as the protective film that can be used in the present invention, any material may be used as long as it can be easily peeled off from the adhesive layer. Examples thereof include a polyester film and a polyolefin film surface-treated with silicone or a fluorine compound. Is mentioned.
[0052]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples.
(Elastic modulus)
The measurement of the elastic modulus was performed according to ASTM D882.
(Linear expansion coefficient)
The linear expansion coefficient at a temperature of 50 to 200 ° C. was measured using a TMA120C manufactured by Seiko Denshi Co., Ltd. (sample size: 3 mm, length: 10 mm), and once heated from 10 ° C. to 400 ° C. at a load of 3 g at 10 ° C./min. After warming, the temperature was cooled to 10 ° C., the temperature was further raised at 10 ° C./min, and the average value was calculated from the thermal expansion coefficients at 50 ° C. and 200 ° C. at the time of the second temperature rise.
(Hygroscopic expansion coefficient)
The coefficient of moisture expansion was allowed to stand for 24 hours in an environmental tester at 50 ° C. and 30% Rh, and the film dimensions were measured (L1). Then, the film was allowed to stand in an environmental tester at 50 ° C. and 80% Rh for 24 hours. The dimensions are measured (L2) and calculated by the following equation.
Hygroscopic expansion coefficient (ppm) = (L1-L2) {L1} (80-30) × 10⁶
〔density〕
The density of the film was determined to two decimal places in accordance with ASTM D1505.
[Loop stiffness]
Using a loop stiffness tester manufactured by Toyo Seiki, sample width was 10 mm, loop length was 50 mm, and crushing distance was 10 mm.
[Warp measurement]
The value of the warpage is as follows: TAB tape prepared by the following procedure is cut into a length of 40 mm × a width of 35 mm, left in a room at a humidity of 60% RH and a temperature of 23 ° C. for 72 hours, and is then left still on a flat surface and at four corners. The lifting height was measured and indicated by the average value of the data of four points.
[Punching property]
The FC tape with the protective film was punched out with a mold, and the occurrence of burrs was observed with a microscope.
(Measurement of average molecular orientation axis in film plane)
The measurement was performed on a sample cut into 4 cm × 4 cm using a microwave molecular orientation meter MOA2012A manufactured by KS Systems.
[Solder heat resistant temperature]
After the copper-capped tape was conditioned for 48 hours in an environment of 85 ° C. and 85% RH, the tape was immersed in a solder bath at a predetermined temperature for 1 minute to observe the presence or absence of swelling.
[Measurement of refractive index difference Δn between average orientation axis direction and thickness direction in film plane]
The width of the sample was measured with a microscope. The number of interference fringes was counted using a polarizing microscope and a sodium lamp, and the difference Δn between the average orientation axis direction in the film plane and the refractive index in the thickness direction was calculated.
[0053]
(Reference example) TAB tape creation
(1) 50 parts by weight of a polyamide resin (Platabond M1276 manufactured by Nippon Rilsan), 30 parts by weight of a bisphenol A type epoxy resin (Epicoat 828 manufactured by Yuka Shell Epoxy), 10 parts by weight of a cresol novolak type epoxy resin, and toluene / isopropyl alcohol 1 An adhesive solution was prepared by mixing 45 parts by weight of a diaminodiphenyl sulfone / dicyandiamide 4/1 20% methyl cellosolve solution with a solution obtained by mixing 150 parts by weight of a 1/1 mixed solution,
{Circle around (1)} An adhesive was applied on a 25 μm-thick PET film so as to have a thickness of 11 μm after drying, and dried at 120 ° C. for 2 minutes. The PET film with the B-stage adhesive was slit to a width of 26 mm.
{Circle around (1)} A PET film with a B-stage adhesive is adhered to the center of a 35 mm wide polyimide film, and 1 kg / cm at 90 ° C.²Pressure. The PET film was peeled off and bonded to a copper foil (manufactured by Mitsui Kinzoku, VLP 18 μm thickness) by a roll lamination method. The bonding temperature is 120 ° C and the pressure is 2kg / cm²It is. (TAB tape without etching)
(1) The above copper-clad product is heated at 60 ° C. for 3 hours, at 80 ° C. for 3 hours, at 120 ° C. for 3 hours, at 140 ° C. for 3 hours, and at 160 ° C. for 4 hours. Was cured. (Tape with copper)
(1) After the adhesive was cured, the copper foil was completely removed by etching. (Copper full etching tape)
The following abbreviations are used in the examples.
ODA: 4,4'-oxydianiline
PDA: p-phenylenediamine
BAPP: 2,2'-bis [(4-aminophenoxy) phenyl] propane
TMHQ: p-phenylene bis (trimellitic acid monoester anhydride)
BTDA: 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride
BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride
DMF: N, N-dimethylformamide
(Example 1)
After dispersing 0.027 g of calcium hydrogen phosphate (maximum particle size 5 μm) in 815 g of DMF, 37.31 g of ODA and 20.15 g of PDA were dissolved, and the solution was kept at 0 ° C. Here, 60.04 g of BTDA was gradually added and stirred for 1 hour to completely dissolve BTDA. After slowly adding 51.24 g of TMHQ to this solution and stirring for 1 hour, further adding 16.26 g of PMDA and stirring for 1 hour, the solution viscosity at 23 ° C. was 3000 poise, and the solid content concentration was 18.5 wt%. Was obtained (ODA / PDA / BTDA / TMHQ / PMDA = 50/50/50/30/20).
[0054]
A curing agent composed of 11.4 g of acetic anhydride, 4.8 g of isoquinoline, and 33.8 g of DMF was mixed with 100 g of the polyamic acid solution, stirred, defoamed by centrifugation, and then cast on an aluminum foil. The process from stirring to defoaming was performed while cooling to 0 ° C. The laminate of the aluminum foil and the polyamic acid solution was heated at 90 ° C. for 600 seconds to obtain a self-supporting gel film. This gel film was peeled off from the aluminum foil and fixed to a frame. After heating this gel film at 120 ° C., 250 ° C., 350 ° C., and 450 ° C. for 180 seconds each, and further heating it in a far infrared oven at 400 ° C. for 180 seconds, a 50 μm-thick polyimide film was obtained. Created a tape. Table 1 shows the characteristics of the polyimide film and the TAB tape.
[0055]
(Examples 2 to 11)
Using various monomer compositions, a polyamic acid solution having a solid content of 18.5% by weight and a solution viscosity of 2500 to 3500 poise was obtained in the same manner as in Example 1, and then a polyimide film and a TAB tape were formed using the same process. Obtained. Tables 1 and 2 show the characteristics of these polyimide films and TAB tapes.
[0056]
(Comparative Examples 1-4)
A polyamic acid solution, a polyimide film and a TAB tape were obtained in the same manner as in Example 1. Table 3 shows the properties of the polyimide film and the TAB tape.
[0057]
[Table 1]

[0058]
[Table 2]

[0059]
[Table 3]

[0060]
【The invention's effect】
According to the present invention, a polyimide film that can be suitably used as an insulating material can be provided with the reduction in weight and size of various electronic devices, and the warpage characteristics of a tape used in a flexible printed board or TAB (Tape Automated Bonding) system are improved. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram showing a method for measuring a difference Δn between a refractive index and an average orientation axis direction in a film surface and a thickness direction.

Claims (7)

A polyimide film for semiconductor mounting, wherein the average linear expansion coefficient at 50 to 200 ° C. is 15 to 30 ppm, and the difference Δn between the average orientation axis direction in the film plane and the refractive index in the thickness direction is 0.17 or less. 2. The polyimide film for semiconductor mounting according to claim 1, wherein Δn is 0.15 or less. 3. The polyimide film for semiconductor mounting according to claim 1, wherein the density is 1.46 g / cc or less. 4. The polyimide film for semiconductor mounting according to claim 1, wherein the loop stiffness is 3 to 50 g / cm. Essential components are 20-70 mol% of p-phenylenediamine based on 100 mol% of the diamine component, and 20-80 mol% of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride based on the acid component. The polyimide film for semiconductor mounting according to claim 1, wherein the polyimide film is used as: A polyimide film with an adhesive, comprising at least the polyimide film according to claim 1, an adhesive layer, and a protective film. A semiconductor package obtained by using the polyimide film with an adhesive according to claim 6.

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