WO2013111241A1 - Polyimide precursor and resin composition using same - Google Patents

Abstract

Provided is a polyimide precursor that has a constitutional unit represented by formula (I) and has an amino group on a part of a terminal group, wherein an integrated value of a peak (A) in the ¹H-NMR spectrum, which indicates a hydrogen atom attached to a carbon atom next to the carbon atom to which the amino group is attached, is 3 to 8% of an integrated value of a peak (B) in the ¹H-NMR spectrum, which indicates a hydrogen atom in an amide bond of the polyimide precursor. In formula (I), A¹ and A² are each a benzene ring, a group in which two benzene rings are connected by a single bond, or a group in which two or more aromatic rings are connected by -O-, -S- or -CO-. R is each a hydrogen atom or an alkyl group. A¹ and A² may each have a substituted group. (I)

Description

Polyimide precursor and resin composition using the same

The present invention relates to a polyimide precursor, a resin composition using the same, a polyimide molded body obtained from the resin composition, a protective layer comprising the molded body, a semiconductor device having a protective layer, a method for manufacturing a semiconductor device, and a semiconductor device. The present invention relates to an electric component or an electronic component.

In recent years, with the miniaturization and high integration of semiconductor packages, a multilayer wiring structure in which wirings for connecting semiconductor elements or wirings for connecting semiconductor elements to external elements is formed in many layers has attracted attention. The multilayer wiring structure has a structure in which a conductive portion (wiring) and a plurality of insulating layers are stacked. In general, a metal having good conductivity such as copper or aluminum is used for the conductive portion, and an inorganic material having an insulating property such as SiO ₂ , SiN, or SiC is used for the insulating layer.

Insulating layers using inorganic substances (hereinafter also referred to as inorganic layers) are inferior in mechanical properties (for example, elongation at break and elastic modulus), so it is necessary to form a protective layer (stress relieving material). In addition, a polyimide resin (polyimide molded body) excellent in insulation is used (Patent Document 1).

A method of forming the inorganic layer and the protective layer when a polyimide molded body is used as the protective layer will be described with reference to FIG.
First, a polyimide molded body 2 as a protective layer is formed on a base material (not shown) having an inorganic layer 1 (hereinafter also referred to as a first inorganic layer), and further an inorganic layer 3 (hereinafter referred to as a second layer). (Also referred to as an inorganic layer). As a method for forming the inorganic layers 1 and 3, there is plasma CVD (plasma chemical vapor deposition) which can form a film having a high film formation rate and high flatness.

When forming an insulating layer by plasma CVD, heat treatment at a high temperature is required. However, if heat treatment is performed at a high temperature when the second inorganic layer 3 is formed, stress is generated due to differences in thermal expansion coefficients among the first inorganic layer 1, the polyimide molded body 2, and the second inorganic layer 3. There were problems such as the polyimide molded body 2 peeling off from the inorganic layer 1 and cracks in the inorganic layer. In order to solve this problem, for example, a polyimide molded body having a relatively high Tg has been developed (Patent Document 2).

JP 2006-318989 A JP 2007-272072 A

However, even when the present inventors use the polyimide molded body of Patent Document 2, if the polyimide molded body is exposed to a high temperature exceeding the glass transition temperature (Tg), deformation of the polyimide molded body 2 occurs, The stress generated from the difference in thermal expansion coefficient between each of the inorganic layer 1, the polyimide molded body 2 and the second inorganic layer 3 cannot be sufficiently suppressed, and peeling of the polyimide molded body 2 or cracking of the inorganic layer is caused. I found that I could not prevent it enough.

The present invention provides a polyimide precursor capable of forming a polyimide molded body that can suppress the thermal expansion of the polyimide molded body itself even when heat exceeding Tg is applied and can relieve stress due to lamination of inorganic layers. For the purpose.
Specifically, it aims at providing the polyimide precursor which gives the polyimide molded object with a low thermal expansion coefficient in a temperature range higher than Tg of a polyimide molded object.
Moreover, an object of this invention is to provide the polyimide precursor which gives the polyimide molded object with high Tg.

According to the present invention, the following polyimide precursors and the like are provided.
<1> A polyimide precursor having a structural unit represented by the following formula (I) and having an amino group as part of a terminal group, which is bonded to a carbon atom adjacent to the carbon atom to which the amino group is bonded. integrated value of the ¹ H-NMR spectrum of a peak indicating a hydrogen atom (a) is, in 3-8% of the integrated value of the ¹ H-NMR spectrum of a peak indicating a hydrogen atom of the amide bonds of the polyimide precursor (B) A polyimide precursor.
(In the formula (I), A ¹ and A ² are each independently a benzene ring, a group in which two benzene rings are bonded by a single bond, or two or more aromatic rings are each represented by —O—, —S— , Or —CO—, A ¹ and A ² each may have a substituent, R ¹ and R ² each independently represents a hydrogen atom or an alkyl group, respectively. Is shown.)
<2> The polyimide precursor having a weight average molecular weight of 40,000 to 100,000.
<3> A resin composition comprising the polyimide precursor and a solvent.
<4> A polyimide molded body obtained by heating the resin composition at 250 to 500 ° C.
<5> A protective layer comprising the polyimide molded body.
<6> A semiconductor device having the protective layer.
<7> A step of applying the resin composition on the first inorganic layer, a step of heating the resin composition to obtain a polyimide molded body, and a temperature higher than Tg of the polyimide molded body on the polyimide molded body A method for manufacturing a semiconductor device, comprising a step of forming a second inorganic layer.
<8> A semiconductor device obtained by the manufacturing method.
<9> An electrical component or electronic component having the semiconductor device.

ADVANTAGE OF THE INVENTION According to this invention, the polyimide precursor which gives the polyimide molded body with a low thermal expansion coefficient in the temperature range higher than Tg of a polyimide molded body can be provided.
Moreover, according to this invention, the polyimide precursor which gives the polyimide molded body with high Tg can be provided.

¹ is an example of a ¹ H-NMR chart of a polyimide precursor of the present invention. It is the schematic of the plot which measured the thermal expansion of the polyimide hardened | cured material with the fixed temperature increase rate. It is a schematic cross section which shows the multilayer wiring structure of one Embodiment of the semiconductor device of this invention. It is a side view which shows a part of multilayer wiring structure in a semiconductor device.

Hereinafter, embodiments according to the present invention will be described in detail. In addition, this invention is not limited by this embodiment.

　式（Ｉ）中、Ａ^１及びＡ^２は各々独立に、ベンゼン環、２個のベンゼン環が単結合で結合した基、又は２個以上の芳香環が、－Ｏ－、－Ｓ－、又は－ＣＯ－のいずれかで結合した基を示す。Ｒ^１及びＲ^２は各々独立に、水素原子又はアルキル基を示す。尚、Ａ^１及びＡ^２はそれぞれ置換基を有していてもよい。 [Polyimide precursor]
The polyimide precursor (polyamic acid) of this invention has a structural unit shown by following formula (I), and has an amino group in a part of terminal group.
The integral value of ¹ H-NMR (nuclear magnetic resonance spectroscopy) spectrum peak (A) indicating a hydrogen atom bonded to a carbon atom adjacent to the carbon atom to which the amino group is bonded is the amide bond of the polyimide precursor. 3 to 8% of the integrated value of the ¹ H-NMR spectrum peak (B) showing the hydrogen atom having the hydrogen atom.

In the formula (I), A ¹ and A ² are each independently a benzene ring, a group in which two benzene rings are bonded by a single bond, or two or more aromatic rings are —O—, —S—, or A group bonded by any one of -CO- is shown. R ¹ and R ² each independently represent a hydrogen atom or an alkyl group. A ¹ and A ² may each have a substituent.

Examples of A ¹ include a group represented by the following formula. Examples of A ² include groups in which a group represented by the following formula is tetravalent.

A ¹ is preferably an aromatic ring or a group in which two aromatic rings are bonded by a single bond (for example, a biphenylene group).
A ² is preferably an aromatic ring or a group in which two aromatic rings are bonded by a single bond (for example, a group having a biphenylene group made tetravalent).
Examples of the aromatic ring include a benzene ring and a benzene ring having an organic group having 1 to 3 carbon atoms. A benzene ring is preferred.
The alkyl group for R is preferably an alkyl group having 1 to 4 carbon atoms, more preferably 3.

In the polyimide precursor of the present invention, the integral value of the NMR peak (A) of hydrogen in the carbon adjacent to the carbon to which the amino group present as the terminal group of the polyimide precursor is bonded is the hydrogen of the amide bond of the polyimide precursor. It is 3 to 8% of the integrated value of the NMR peak (B) showing atoms.

The terminal group of the polyimide precursor is not a substituent (side chain substituent) contained in the structural unit represented by the formula (I), but represents groups at both terminals of the structural unit represented by the formula (I). .

FIG. 1 is an example of a ¹ H-NMR chart of the polyimide precursor of the present invention.
The peak (A) is a hydrogen peak in the carbon adjacent to the carbon to which the amino group present as the end group of the polyimide precursor is bonded, and usually appears at 6 to 7 ppm.
The peak (B) is a peak indicating a hydrogen atom of the amide bond of the polyimide precursor, and usually appears at 10.4 to 10.8 ppm.

When the value obtained by [integral value of peak (A)] ÷ [integral value of peak (B)] × 100 is 3 to 8, the integrated value of peak (A) is 3 of the integrated value of peak (B). It can be said that it is ˜8%.

When the integral value of the peak (A) is 3% or more of the integrated value of the peak (B), since the alpha ₂ decreases, it is possible to relax the stress due to lamination of the inorganic layer at temperatures above Tg, 8 % Or less improves the mechanical properties and heat resistance of the polyimide molded body.
The integrated value of peak (A) is preferably 5 to 8% of the integrated value of peak (B), more preferably 6 to 8%, and even more preferably 6.5 to 8%. .

The polyimide precursor of the present invention can provide a polyimide molded body having a high Tg and a low α ₂ . If the alpha ₂ was used lower polyimide molded body, a polyimide molded product even when exposed to a temperature higher than Tg, it is possible to prevent significant thermal expansion, reducing the stress resulting from the difference in thermal expansion between the inorganic layer be able to.
Furthermore, the polyimide precursor of the present invention can provide a polyimide molded body having a high Tg, a low coefficient of thermal expansion (CTE) in a temperature region lower than Tg, and excellent mechanical properties.

The weight average molecular weight in terms of standard polystyrene of the polyimide precursor of the present invention is 40000 to 100,000 from the viewpoint of further improving heat resistance (Tg, coefficient of thermal expansion (CTE), α ₂ etc.) and mechanical properties (elongation at break). It is preferably 50,000, more preferably 50,000 to 90,000, and even more preferably 50,000 to 75,000.

When the weight average molecular weight is 40000 or more, the polyimide precursor can be easily obtained by heating the polyimide precursor, and the mechanical properties of the obtained polyimide molded body tend to be improved. When the weight average molecular weight is 100,000 or less, it is easy to control the molecular weight when synthesizing the polyimide precursor, and the viscosity tends to be low, and it tends to be uniformly applied on the substrate.
A weight average molecular weight can be calculated | required by standard polystyrene conversion using a gel permeation chromatography method (GPC).

The amino group of the terminal group of the polyimide precursor of the present invention is usually a residue of diamines used for the synthesis of the polyimide precursor described below, but in order to impart a terminal group in the synthesis of the polyimide precursor. It may be an amino group derived from the aminophenol used.

[Synthesis of polyimide precursor]
The polyimide precursor of the present invention is a polyamic acid obtained by polymerizing tetracarboxylic acid and its derivatives (tetracarboxylic acids and their derivatives together, referred to as tetracarboxylic acids) and diamines. It can be obtained by polymerizing tetracarboxylic dianhydride obtained by dehydrating and ring-closing carboxylic acids and diamines.

A polyimide precursor in which the integrated value of the peak (A) is 3 to 8% of the integrated value of the peak (B) can be obtained, for example, by adjusting the ratio of the tetracarboxylic acid to be polymerized and the diamine. Is possible.
For example, by performing polymerization at a ratio of tetracarboxylic acids: diamines (molar ratio) = 96: 100 to 98: 100, the integrated value of peak (A) is 3 to 8% of the integrated value of peak (B). A certain polyimide precursor can be obtained.

As the tetracarboxylic acids used for the synthesis of the polyimide precursor of the present invention, general tetracarboxylic acids can be used. From the viewpoint of lowering CTE, it is preferable to use tetracarboxylic acids having a rigid skeleton. Specifically, for example, it is more preferable to use pyromellitic anhydride and biphenyl-3,3 ', 4,4'-tetracarboxylic dianhydride.

Examples of diamines used for the synthesis of the polyimide precursor of the present invention include commonly used aromatic diamines. For example, a compound in which 1, 2 or 3 benzene rings are linked by a single bond and 2 amino groups are bonded thereto, and 1, 2 or 3 benzene rings are —O—, —S—, or A compound in which two amino groups are bonded to each other by linking with —CO— is exemplified.
When the aromatic diamine has one benzene ring, the two amino groups are preferably bonded at the para position or the meta position. When the aromatic diamine has two or more benzene rings, the two amino groups are preferably bonded to different benzene rings. As the aromatic diamine, for example, p-phenylenediamine, m-phenylenediamine and 2,2′-dimethyl-4,4′-diaminobiphenyl are preferably used from the viewpoint of lowering CTE.

The polyimide precursor of the present invention can be synthesized by a conventionally known polyamic acid synthesis method. For example, after dissolving a predetermined amount of diamines in a solvent, tetracarboxylic dianhydride obtained by heating and dehydrating and ring-closing tetracarboxylic acids for 24 hours at 160 ° C. in a drier is obtained. Add a predetermined amount and stir.

By adjusting the blending amount of diamines and tetracarboxylic acids, the integrated value of the peak (A) of the NMR spectrum of hydrogen in the carbon adjacent to the carbon to which the amino group present as the end group of the polyimide precursor is bonded, A polyimide precursor that is 3 to 8% of the integrated value of the peak (B) of the NMR spectrum showing the hydrogen atom of the amide bond of the polyimide precursor can be obtained.

When dissolving each monomer component, it may be heated as necessary. The reaction temperature is preferably −30 to 200 ° C., more preferably 20 to 180 ° C., and further preferably 30 to 100 ° C. Stirring is continued at room temperature (20 to 25 ° C.) or at the reaction temperature as described above, and the time when the viscosity of the polyamic acid becomes constant is taken as the end point of the reaction.

Viscosity can be measured at 25 ° C. using an E-type viscometer (for example, manufactured by Toki Sangyo Co., Ltd.). The reaction can be usually completed in 3 to 100 hours, although depending on the types of tetracarboxylic acids and diamines used.

The polyamic acid component (hereinafter referred to as a solute) is 5 to 60% by mass with respect to the total amount of the resulting solution containing the polyimide precursor (hereinafter referred to as the polyamic acid solution) from the viewpoint of applicability to the substrate. Is preferably 10 to 50% by mass, more preferably 10 to 40% by mass.

The ratio of the solute (resin non-volatile content) in the polyamic acid solution is determined by taking the polyamic acid solution into a metal petri dish having a known mass in advance (about 1 g as a guide) and mass (mass of the metal petri dish and polyamic acid, hereinafter, Mass after heating (on a hot plate with a surface temperature of 200 ° C.) for 2 hours and the solvent is sufficiently volatilized (mass of metal petri dish and solute, hereinafter referred to as mass after heating) ) Is measured and (mass after heating−mass of metal petri dish) ÷ (mass before heating−mass of metal petri dish) × 100 is calculated.

The solvent used for synthesizing the polyimide precursor of the present invention is not particularly limited as long as it is a solvent capable of dissolving diamines, tetracarboxylic acids, and polyimide precursors. Specific examples of such solvents include aprotic solvents, phenol solvents, ethers and glycol solvents.

Examples of the aprotic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea and the like. Amide solvents: lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide; sulfur-containing dimethylsulfone, dimethylsulfoxide, sulfolane and the like Solvents: ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; ester solvents such as acetic acid (2-methoxy-1-methylethyl).

Examples of the phenol solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4 -Xylenol and 3,5-xylenol.

Examples of the ether and glycol solvents include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane, propylene glycol monomethyl ether and the like.
N-methyl-2-pyrrolidone is preferred from the viewpoint of solubility and coatability to the substrate. These solvents may be used alone or in combination of two or more.

The polyamic acid solution is preferably 500 to 200,000 mPa · s at 25 ° C., more preferably 2000 to 100,000 mPa · s, and even more preferably 5000 to 30,000 mPa · s. Here, the viscosity is a value measured at 25 ° C. using an E-type viscometer (VISCONIC EHD manufactured by Toki Sangyo Co., Ltd.). The rotation speed is usually measured in the range of 0.5 to 100 rpm, although the preferred speed varies depending on the viscosity range to be measured.

When the viscosity is 500 mPa · s or more, the polyimide precursor solution can be easily applied to the substrate, and when it is 200,000 mPa · s or less, stirring during synthesis is easy. However, in order to obtain a polyimide precursor solution having a viscosity of 200,000 mPa or less during synthesis of the polyimide precursor, it is also possible to obtain a polyamide acid solution having a good handleability by adding a solvent after the reaction and stirring. It is.

[Resin composition]
The resin composition of this invention contains said polyimide precursor and a solvent.

[solvent]
The resin composition of the present invention preferably uses a solvent (solvent) as necessary.
The solvent is not particularly limited as long as it can dissolve the polyimide precursor of the present invention, and as such a solvent, those described as solvents that can be used at the time of synthesis of the polyimide precursor can be used. The solvent may be the same as or different from the reaction solvent used in the synthesis of the polyamic acid.
The content of the solvent is preferably adjusted and added so that the viscosity of the resin composition at 25 ° C. is 5 Pa · s to 100 Pa · s.

Further, the boiling point of the solvent at normal pressure is preferably 60 to 210 ° C., more preferably 100 to 205 ° C., and further preferably 140 to 180 ° C. When the boiling point is 210 ° C. or lower, the time required for the drying step can be shortened. Further, when the temperature is 60 ° C. or higher, it is possible to suppress the roughness of the film surface and to prevent bubbles from entering the film.

[Other ingredients]
The resin composition of the present invention may contain (1) an adhesion-imparting agent, (2) a surfactant or a leveling agent, in addition to the polyimide precursor and the solvent.

[Other components: (1) Adhesiveness imparting agent]
The resin composition of the present invention may contain (1) an adhesion-imparting agent such as an organic silane compound or an aluminum chelate compound, for example, in order to enhance the adhesion of the cured film to the substrate.

Examples of the organic silane compound include vinyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, ureapropyltriethoxysilane, methylphenylsilanediol, ethylphenylsilanediol, n- Propylphenylsilanediol, isopropylphenylsilanediol, n-butylphenylsilanediol, isobutylphenylsilanediol, tert-butylphenylsilanediol, diphenylsilanediol, ethylmethylphenylsilanol, n-propylmethylphenylsilanol, isopropylmethylphenylsilanol, n-butylmethylphenylsilanol, isobutylmethylphenylsilanol, tert-butylmethylphenylsilanol , Ethyl n-propylphenylsilanol, ethylisopropylphenylsilanol, n-butylethylphenylsilanol, isobutylethylphenylsilanol, tert-butylethylphenylsilanol, methyldiphenylsilanol, ethyldiphenylsilanol, n-propyldiphenylsilanol, isopropyldiphenylsilanol , N-butyldiphenylsilanol, isobutyldiphenylsilanol, tert-butyldiphenylsilanol, phenylsilanetriol, 1,4-bis (trihydroxysilyl) benzene, 1,4-bis (methyldihydroxysilyl) benzene, 1,4-bis (Ethyldihydroxysilyl) benzene, 1,4-bis (propyldihydroxysilyl) benzene, 1,4-bis (butyldi) Droxysilyl) benzene, 1,4-bis (dimethylhydroxysilyl) benzene, 1,4-bis (diethylhydroxysilyl) benzene, 1,4-bis (dipropylhydroxysilyl) benzene and 1,4-bis (dibutylhydroxysilyl) ) Benzene.

Examples of the aluminum chelate compound include tris (acetylacetonate) aluminum and acetylacetate aluminum diisopropylate.
When using these (1) adhesion-imparting agents, the blending amount is not particularly limited. For example, from the viewpoint of providing good adhesion, 0.1 to 20 parts by mass with respect to 100 parts by mass of the polyimide precursor It is preferably contained, and more preferably 0.5 to 10 parts by mass.

[Other components: (2) Surfactant (also called leveling agent)]
In addition, the resin composition of the present invention may contain an appropriate (2) surfactant in order to prevent coating properties, for example, striation (film thickness unevenness).
Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether.

Commercially available products include Megafax F171, F173, R-08 (trade name, manufactured by Dainippon Ink and Chemicals (DIC)), Florard FC430, FC431 (trade name, manufactured by Sumitomo 3M), organosiloxane. Examples thereof include polymers KP341, KBM303, KBM403, and KBM803 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

In the case of using these (2) surfactants, the blending amount is not particularly limited. For example, from the viewpoint of giving good coatability, 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyimide precursor It is preferable to contain 0.05 to 5 parts by mass.

The method for producing the resin composition of the present invention is not particularly limited. For example, when the reaction solvent and the solvent are the same when the polyimide precursor is synthesized, the synthesized polyamic acid solution is used as the resin composition. It can be. Further, a method of adding an organic solvent and, if necessary, other additives to the polyamide precursor solution in a temperature range of room temperature (25 ° C.) to 80 ° C. and stirring and mixing may be mentioned.

This stirring and mixing can be performed using a device such as a three-one motor (manufactured by Shinto Chemical Co., Ltd.) equipped with a stirring blade and a rotating and rotating mixer. If necessary, heat of 40 to 100 ° C. may be applied. When the reaction solvent and the organic solvent are different when synthesizing the polyimide precursor, the reaction solvent in the synthesized polyamic acid solution is removed by a method of reprecipitation or solvent distillation, and after obtaining a polyimide precursor, Examples thereof include a method obtained by adding an organic solvent and, if necessary, other additives in a temperature range of room temperature to 80 ° C., and stirring and mixing.

The viscosity at 25 ° C. of the resin composition of the present invention is preferably 5 to 100 Pa · s, preferably 5 to 50 Pa · s from the viewpoint of workability in the coating process, although it depends on the intended use and purpose. Is more preferable, and 5 to 30 Pa.s. More preferably, it is s.

[Polyimide molded product]
The polyimide molded body of the present invention can be obtained by subjecting a resin film obtained by applying and drying the resin composition of the present invention to heat treatment (imidization).

The method for producing a polyimide molded body includes (1) a step of applying the resin composition of the present invention on a substrate, (2) a step of drying the applied resin film with heat at 80 to 200 ° C. to form a resin film, (3) It is preferable to include a step of heat-treating the resin film after drying with heat at 250 ° C. to 500 ° C. to imidize the polyimide precursor in the resin composition.

Hereinafter, each step will be described.
(1) Coating process There is no restriction | limiting in particular in the coating method in a coating process, According to the desired coating thickness or the viscosity of a resin composition, etc., it can select and use a well-known coating method suitably. Specifically, application methods using a doctor blade, knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, bar coater, spin coat, spray coat, dip coat, etc., screen printing Alternatively, a printing method using a printing technique such as gravure printing can be applied.

The substrate on which the resin composition is applied is not particularly limited as long as it has heat resistance at the drying temperature in subsequent steps.
For example, glass substrate, silicon wafer substrate, metal substrate such as stainless steel, alumina, copper, nickel, PET (polyethylene terephthalate), OPP (stretched polypropylene) polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamideimide, polyether Examples of the resin substrate include imide, polyetheretherketone, polyethersulfone, polyphenylenesulfone, and polyphenylenesulfide.

In addition, since the resin composition of the present invention is particularly useful to be applied on an inorganic layer such as SiN, SiC, SiO ₂ and used to form a protective layer, the resin composition is applied to a substrate including these inorganic layers. It is preferable to use it.

The film thickness when applying the resin composition of the present invention is appropriately adjusted depending on the thickness of the target polyimide molded body and the resin non-volatile content in the resin composition, but is usually 0.1-100 μm. Degree. The resin non-volatile content can be obtained by the method described above. The coating step is usually performed at room temperature, but the resin composition may be heated in the range of 40 to 80 ° C. for the purpose of reducing the viscosity and improving workability.

(2) A drying step is performed following the coating step. A drying process is performed in order to remove a solvent. In the drying process, devices such as a hot plate, a box-type dryer, and a conveyor-type dryer can be used. The drying temperature is preferably 80 to 200 ° C, and more preferably 100 to 150 ° C.

Subsequently, (3) a heating step is performed. This heating step is a step of (2) removing the solvent remaining in the resin film in the drying step and advancing the imidization reaction of the polyimide precursor in the resin composition.
A heating process can be performed using apparatuses, such as an inert gas oven, a hot plate, a box-type dryer, and a conveyor type dryer. Moreover, this process may be performed simultaneously with said (2) drying process, or may be performed sequentially.

The heating step may be performed in an air atmosphere, but is preferably performed in an inert gas atmosphere from the viewpoint of safety and oxidation prevention. Examples of the inert gas include nitrogen and argon.

The heating temperature is appropriately adjusted depending on the type of the organic solvent, but is preferably 250 ° C. to 400 ° C., more preferably 350 to 400 ° C. from the viewpoint of providing a cured film having good mechanical properties. In view of the good progress of imidization, 250 ° C. or higher is preferable. Moreover, 400 degrees C or less is preferable at the point which is excellent in heat resistance. The heating time is usually about 0.5 to 3 hours.

The obtained polyimide molded body can also form a pattern by a resist process according to a use.
Examples of the resist process include (3) a method of applying a resist after the heating step and forming a pattern by exposure and development.

Resist materials and materials used for etching are not particularly limited as long as they are used in a normal resist process. For example, it is possible to apply either wet etching or dry etching as an etching method, and examples of the etching solution used for wet etching include hydrazine hydrate, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, and the like. It is done.

Also, as dry etching, methods such as oxygen plasma etching and oxygen sputter etching can be employed. After the pattern formation, the resist can be peeled off from the polyimide molded body using an organic solvent. Examples of the organic solvent include ethanolamine, NMP (N-methyl-2-pyrrolidone), DMSO (dimethyl sulfoxide), and a mixture thereof can also be used.

The amount of residual organic solvent after the production of the polyimide molded body of the present invention is preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less. The amount of residual solvent can be measured by GC-MS (gas chromatography mass spectrometry).

As for the mechanical properties of the polyimide molded body of the present invention, the tensile modulus is preferably 3 GPa or more in both the width direction and the operation direction. The tensile strength is preferably 100 MPa or more, and more preferably 200 MPa or more. The breaking elongation is preferably 30 to 100%.
All of these mechanical properties can be determined by a tensile test using a tensile test apparatus.
If the polyimide molded body has these mechanical characteristics, the inorganic layer can be sufficiently protected in the multilayer wiring structure. Moreover, it is said that it has sufficient toughness as a polyimide molded body utilized as a semiconductor device, and can be used practically.

The glass transition temperature (Tg) of the polyimide molded body of the present invention is preferably 250 to 440 ° C, more preferably 350 to 400 ° C. A Tg of 350 to 400 ° C. is regarded as having excellent heat resistance when used in a semiconductor device. Tg can be measured by the method described in Examples described later.

[Protective layer / semiconductor device / semiconductor device manufacturing method / electrical / electronic component]
The protective layer of the present invention uses the polyimide molded body described above. For example, in a semiconductor device, it can be used as a protective layer for protecting a first inorganic layer such as SiN, SiC, or SiO ₂ .

Examples of the semiconductor device of the present invention include a multilayer wiring structure. Such a semiconductor device includes a step of applying a resin composition on a substrate having an inorganic layer (also referred to as a first inorganic layer), a step of heating the resin composition to obtain a polyimide molded body, and the polyimide It can be manufactured by a step of further forming an inorganic layer (also referred to as a second inorganic layer) on the molded body at a temperature higher than Tg of the polyimide molded body.
As a method of forming the first or second inorganic layer, there is plasma CVD (plasma chemical vapor deposition) that can form a film having a high film formation rate and high flatness.

FIG. 4 shows an example of a multilayer wiring structure, in which the multilayer wiring structure and a part thereof are enlarged. In FIG. 4, 10 is a semiconductor substrate, 20 is a semiconductor element, 30 is an insulating layer, and 40 is a metal wiring. Insulating layer, SiN, SiC, consists SiO _2, polyimide (PI) molding body is used in the present invention as a protective layer.

Since the polyimide molded body of the present invention has a small coefficient of thermal expansion (α ₂ ) in a temperature region higher than Tg, even when the second inorganic layer is formed at a temperature higher than Tg, it can prevent significant expansion of the film. , Deformation or misalignment of the film can be prevented.
If the alpha ₂ was used low polyamide molding material, also polyimide molded product is exposed to a temperature higher than Tg, it is possible to prevent significant thermal expansion, reducing the stress generated by the difference in thermal expansion between the inorganic layer It is thought that deformation of the polyimide molded body can be prevented.

The semiconductor device of the present invention can be used for electronic components because the polyimide molded body has heat resistance and mechanical properties. Here, as an electronic component, a semiconductor device, a multilayer wiring board, a mobile phone, a smart phone, various electronic devices used for a computer, etc. are included.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Synthesis example 1
[Synthesis of Polymer A]
In a 0.3 liter flask equipped with a stirrer and a thermometer, 238 g of N-methylpyrrolidone and 10.8 g (100 mmol) of p-phenylenediamine were charged, dissolved by stirring, and then biphenyl-3,3 ′, 4,4 28.25 g (96 mmol) of '-tetracarboxylic dianhydride was added and stirred well to dissolve completely. Then, it stirred for about 24 hours until molecular weight became fixed, and the polyimide precursor solution (polymer A solution) was obtained. In addition, the resin non volatile matter (NV) of the polymer A solution was 14.1%.

In addition, content (resin non-volatile content) of a polyimide precursor takes a polyimide precursor composition to a metal petri dish whose mass is known beforehand (about 1 g as a guide), and mass (metal petri dish and polyimide precursor composition). Mass, hereinafter referred to as mass before heating), and then heated on a hot plate for 2 hours to sufficiently evaporate the solvent, etc. (mass of metal petri dish and polyimide precursor, hereinafter, after heating) The mass was measured and calculated by (mass after heating−mass of metal petri dish) ÷ (mass before heating−mass of metal petri dish) × 100.

The weight average molecular weight of the polymer A was determined by standard polystyrene conversion using a gel permeation chromatography method. The weight average molecular weight of the polymer A was 50,000.

Specifically, the weight average molecular weight was measured with the following apparatus and conditions.
Measuring device: Detector L4000UV manufactured by Hitachi, Ltd.
Pump: L6000 manufactured by Hitachi, Ltd.
C-R4A Chromatopac manufactured by Shimadzu Corporation
Measurement conditions: Column Gelpack GL-S300MDT-5 × 2 eluent: THF / DMF = 1/1 (volume ratio)
LiBr (0.03 mol / l), H ₃ PO ₄ (0.06 mol / l)
Flow rate: 1.0 ml / min, detector: UV 270 nm
The measurement was performed using a solution of 1 ml of a solvent [THF / DMF = 1/1 (volume ratio)] with respect to 0.5 mg of the polymer.

Further, the ¹ H-NMR spectrum of polymer A was measured. The measurement conditions are as follows.
Measuring instrument: AV400M manufactured by Bruker BioSpin
Magnetic field strength: 400MHz
Reference material: Tetramethylsilane (TMS)
Solvent: DMSO

In the obtained NMR spectrum, the value obtained by [integral value of peak (A)] ÷ [integral value of peak (B)] × 100 is the integrated value of peak (B) of the integrated value of peak (A). It shows in Table 1 as a ratio with respect to.
In the formula, the peak (A) is a peak indicating a hydrogen atom bonded to a carbon atom adjacent to the carbon atom to which the amino group of the terminal group is bonded, and the peak (B) is a hydrogen having an amide bond of the polyimide precursor. It is an atomic peak.
The ratio of the integrated value of peak (A) to the integrated value of peak (B) reflects the ratio of amino groups as terminal groups in polymer A.

Synthesis Examples 2-7
[Synthesis of Polymers B to I]
Polyimide precursors (Polymers B to I) were synthesized in the same manner as in Synthesis Example 1 except that the compounding amounts of amine, acid and NMP were changed as shown in Table 1. The same amine and acid as those used for polymer A were used. Further, in the same manner as in Synthesis Example 1, the ratio of the integrated value of peak (A) to the integrated value of weight average molecular weight (Mw) and peak (B) was determined. The results are shown in Table 1.

Example 1
[Preparation of cured film]
The polymer A solution (resin composition) was filtered using a 5 μm filter (Millipore, SLLS025NS).
The obtained resin composition was spin-coated on a silicon wafer and dried at 110 ° C. for 3 minutes and 140 ° C. for 3 minutes to form a resin film having a thickness of 10 μm. This was further heated in a nitrogen atmosphere using an inert gas oven to obtain a cured film (polyimide molded product) having a film thickness of 5 μm.

The conditions for heating with the inert gas oven are as follows.
Equipment: Inert gas oven manufactured by Koyo Thermo System Co., Ltd. Conditions: Temperature rise Room temperature to 200 ° C (5 ° C / min)
Hold 200 ° C (30 minutes)
Temperature increase 200 ° C to 375 ° C (5 ° C / min)
Hold 375 ° C (60 minutes)
Cooling 375 ° C to room temperature (60 minutes)

[Evaluation of Tg, CTE, α ₂ and elongation at break]
Next, this cured film was peeled off from the silicon wafer using a 4.9% by mass hydrofluoric acid aqueous solution, washed with water and dried, and then at a glass transition temperature (Tg), a coefficient of thermal expansion (CTE), and a temperature higher than Tg. The coefficient of thermal expansion (α ₂ ) and elongation at break were examined.
FIG. 2 is a schematic diagram of a plot in which the thermal expansion of the polyimide cured product is measured at a constant temperature increase rate. Tg is the temperature at the intersection of the tangent a and b, CTE is the slope of the tangent b, alpha ₂ is the slope of the tangent a.

In this example, a TMA / SS6000 manufactured by Seiko Instruments Inc. is used to automatically calculate the Tg, I asked the CTE and α _2. The elongation at break was determined by a tensile test using Autograph AGS-100NH manufactured by Shimadzu Corporation under room temperature conditions (15 to 30 ° C.).

Examples 2 to 5 and Comparative Examples 1 to 4
A resin composition and a cured film were prepared and evaluated in the same manner as in Example 1 except that the type of polymer and the amount of the solvent (NMP, water) were changed as shown in Table 1. The results are shown in Table 1.

When using a polyimide precursor in which the ratio of the integrated value of the peak (A) to the integrated value of the peak (B) is 3 to 8% as in Examples 1 to 5, good Tg, CTE, α ₂ , The elongation at break was shown.
On the other hand, when the ratio of the integrated value of the peak (A) to the integrated value of the peak (B) was more than 8% as in Comparative Example 1 or 2, the Tg was low and the elongation at break was also reduced. If the ratio of the integrated value of the peak (A) to the integral value of the peak (B) as in Comparative Example 2 or 3 is less than 3%, alpha ₂ is increased.

As described above, the polyimide molded body using the resin composition of this example has high Tg, low α ₂ , low CTE, and excellent mechanical properties.
Since the polyimide molded body of this example has a high Tg and a low α ₂ , thermal expansion is required when forming a multilayer wiring structure in which an inorganic layer is formed on the polyimide formed body at a temperature higher than Tg. It is possible to prevent deformation and misalignment of the polyimide molded body due to.

The polyimide molded body of the present invention can be used as a display substrate or a protective film.

Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will appreciate that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.
The contents of the documents described in this specification and the specification of the Japanese application that is the basis of Paris priority of the present application are all incorporated herein.

Claims (9)

A polyimide precursor having a structural unit represented by the following formula (I) and having an amino group as a part of a terminal group, wherein a hydrogen atom bonded to a carbon atom adjacent to the carbon atom to which the amino group is bonded. ¹ integrated value of H-NMR spectrum of the peak (a) is a polyimide precursor is 3-8% of the integrated value of the ¹ H-NMR spectrum of a peak indicating a hydrogen atom of the amide bonds of the polyimide precursor (B) shown body.

(In the formula (I), A ¹ and A ² are each independently a benzene ring, a group in which two benzene rings are bonded by a single bond, or two or more aromatic rings are —O—, —S—, or A group bonded by any one of —CO—, R ¹ and R ² each independently represents a hydrogen atom or an alkyl group, and A ¹ and A ² each may have a substituent. The polyimide precursor according to claim 1, having a weight average molecular weight of 40,000 to 100,000. A resin composition comprising the polyimide precursor according to claim 1 or 2 and a solvent. A polyimide molded body obtained by heating the resin composition according to claim 3 at 250 to 500 ° C. A protective layer comprising the polyimide molded body according to claim 4. A semiconductor device having the protective layer according to claim 5. The process of apply | coating the resin composition of Claim 3 on the inorganic layer of the base material which has an inorganic layer, the process of heating the said resin composition and obtaining a polyimide molded body, and the said polyimide on the said polyimide molded body The manufacturing method of a semiconductor device including the process of forming an inorganic layer further at temperature higher than Tg of a molded object. A semiconductor device obtained by the manufacturing method according to claim 7. An electrical component or electronic component having the semiconductor device according to claim 8.

Images