JP6776733B2 - Positive photosensitive resin composition - Google Patents

Description

The present invention relates to a positive photosensitive resin composition, a method for producing a pattern cured film using the same, a cured film obtained by curing the positive photosensitive resin composition, an interlayer insulating film using the cured film, a cover coat layer, or the like. The present invention relates to a surface protective film and an electronic component having the same.

Conventionally, polyimide having excellent heat resistance, electrical properties, mechanical properties, etc. has been used as a surface protective film and an interlayer insulating film of a semiconductor element. In recent years, a photosensitive polyimide having a photosensitive property imparted to the polyimide itself has been used, and when this is used, the manufacturing process of the pattern cured film can be simplified and the complicated manufacturing process can be shortened.

In the manufacturing process of the pattern cured film, an organic solvent such as N-methylpyrrolidone has been used in the developing process. However, in consideration of the environment, resin compositions that can be developed with an alkaline aqueous solution by a method of mixing a diazonaphthoquinone compound as a photosensitive agent with polyimide or a polyimide precursor have been proposed (for example, Patent Documents 1 and 2).

By the way, in recent years, the miniaturization of transistors, which has supported the high performance of computers, has reached the limit of the scaling law, and the technology of three-dimensionally stacking semiconductor elements is indispensable for further high performance and high speed. It is believed that. Against this background, three-dimensional packages using TSVs (Through Silicon Vias), 2.5-dimensional packages using interposers, and 2.1-dimensional packages have been proposed, and laminated devices represented by these have been proposed. The structure is attracting attention (for example, Non-Patent Document 1).

Among the laminated device structures, the multi-die fan-out wafer level package (Multi-die Fanout Wafer Level Packaging) is a package manufactured by collectively encapsulating a plurality of dies in one package, and has been conventionally proposed. It is attracting a great deal of attention because it can be expected to have lower cost and higher performance than a fan-out wafer level package manufactured by encapsulating one die in one package.

In the fabrication of laminated device structures such as multi-die fan-out wafer level packages, rewiring is performed after dicing chips are sealed, but due to the poor heat resistance of the sealing material, low-temperature curable rewiring layers An insulating film is required.

On the other hand, the film properties of polyimide and polybenzoxazole, especially the adhesiveness, tended to decrease as the curing temperature was lowered. In particular, when curing was performed at 200 ° C. or lower, the adhesiveness to various substrates was low.

Japanese Unexamined Patent Publication No. 2009-265520 International Publication No. 2014/115233 Pamphlet

"Semiconductor Technology Yearbook 2013 Packaging / Mounting", Nikkei BP Co., Ltd., December 2012, p. 41-50

The photosensitive resin composition in which a cross-linking agent widely used in the past is combined with a polybenzoxazole precursor has low reactivity with the polybenzoxazole precursor and has adhesiveness to various substrates after being cured at 200 ° C. Turned out to be low. Furthermore, it was also found that the cross-linking agent having low reactivity remains in the membrane in an unreacted state after curing and reduces the adhesiveness after the pressure cooker test (PCT test).

To solve the above problem, by combining a cross-linking agent having a high reactivity with the polybenzoxazole precursor, even when the resin composition is cured at a low temperature of 200 ° C. or lower, it can be applied to various substrates. We have found that it exhibits excellent adhesiveness.

However, when a highly reactive cross-linking agent is used, the polymerization reaction in which the polybenzoxazole precursor and the cross-linking agent are condensed during baking of the coating film is excessively promoted, and the exposed and unexposed areas are subjected to in the developing process. It was found that both of them have reduced solubility in a developing solution, which in turn reduces the sensitivity of the photosensitive resin composition.

Therefore, an object of the present invention is to provide a positive photosensitive resin composition having excellent solubility in a developing solution and photosensitive characteristics even when a highly reactive cross-linking agent is used.

According to the present invention, the following positive photosensitive resin compositions and the like are provided.
[1] It contains (a) a polybenzoxazole precursor, (b) a cross-linking agent, (c) a photosensitizer, (d) a solvent, and (e) an amine compound.
The component (a) contains a structural unit represented by the following formula (1), the component (b) is a compound represented by the following formula (2), and the component (e) is the following formula (3). A positive photosensitive resin composition which is a compound represented by.
(In the formula (1), U is a divalent organic group, a single bond, -O- or -SO _2- , V is a group containing an aliphatic structure, and the aliphatic structure has 1 to 1 carbon atoms. 30.)
(In the formula (2), _{R 1} is each independently at least one of the .R ₁ is a group represented by hydrogen or _{-CH 2 -O-R} 2 is _{-CH 2 -O-R} 2 a is .R ₂ is group represented by a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, when R ₂ is plural, R ₂ may be the same or different.)
(In formula (3), R ₃ is a hydrogen atom or a group represented by -R _4- W, respectively. At least one of R ₃ is a group represented by -R _4- W. R ₄ is an alkylene group having 1 to 3 carbon atoms, and when R ₄ is plural, R ₄ may be the same or different. W is a hydrogen atom, a hydroxyl group or a monovalent organic group. When there are multiple Ws, the Ws may be the same or different.)
[2] The positive photosensitive resin composition according to [1], which contains the component (b) in an amount of 5 parts by mass or more with respect to 100 parts by mass of the component (a).
[3] The positive photosensitive resin composition according to [1] or [2], which contains the component (e) in an amount of 0.3 parts by mass or more with respect to 100 parts by mass of the component (a).
[4] The positive photosensitive resin composition according to any one of [1] to [3], wherein the component (e) has a molecular weight of 50 to 350.
[5] The positive photosensitive resin composition according to any one of [1] to [4], wherein the component (c) is a diazonaphthoquinone compound.
[6] A step of applying the positive photosensitive resin composition according to any one of [1] to [5] onto a substrate and drying it to form a photosensitive resin film.
A step of exposing the photosensitive resin film to a pattern to form a resin film, and
A step of developing the exposed resin film with an alkaline aqueous solution to form a pattern resin film, and
A step of heat-treating the pattern resin film to form a pattern cured film, and
A method for producing a pattern cured film including.
[7] The method for producing a pattern cured film according to [6], wherein the heat treatment temperature is 250 ° C. or lower in the step of heat-treating the pattern resin film.
[8] A cured film obtained by curing the positive photosensitive resin composition according to any one of [1] to [5].
[9] An interlayer insulating film, a cover coat layer or a surface protective film using the cured film according to [8].
[10] An electronic component having the interlayer insulating film, cover coat layer or surface protective film according to [9].

According to the present invention, in order to obtain good adhesiveness to a substrate even when cured at low temperature, positive photosensitive having excellent solubility in a developing solution and photosensitive characteristics even when a highly reactive cross-linking agent is used. A sex resin composition can be provided.

It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. It is schematic cross-sectional view explaining the manufacturing process of a fanout package having a multi-layer wiring structure. FIG. 3 is a schematic cross-sectional view of a fan-out package having a UBM (Under Bump Metal) -free structure.

The following are the positive photosensitive resin composition of the present invention, a method for producing a pattern cured film using the same, a cured film obtained by curing the positive photosensitive resin composition, and an interlayer insulating film using the pattern cured film. Embodiments of a cover coat layer or a surface protective film and an electronic component having the same will be described in detail. The present invention is not limited to the following embodiments.

In the present specification, "A or B" may include either A or B, and may include both. Further, as for the materials exemplified below, one type may be used alone or two or more types may be used in combination unless otherwise specified. Further, in the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means quantity. In the present specification, the term "process" is included in this term not only as an independent process but also as long as the desired action of the process is achieved even if it cannot be clearly distinguished from other processes. .. The numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively.

[Positive Photosensitive Resin Composition]
The positive photosensitive resin composition of the present invention contains (a) a polybenzoxazole precursor, (b) a cross-linking agent, (c) a photosensitive agent, (d) a solvent and (e) an amine compound. Hereinafter, these components may be simply referred to as (a) component, (b) component, (c) component, (d) component and (e) component. Hereinafter, each component will be described.

(Component (a): Polybenzoxazole precursor)
The component (a) includes a structural unit represented by the following formula (1).
In formula (1), U is a divalent organic group, a single bond, -O- or -SO _2- , V is a group containing an aliphatic structure, and the aliphatic structure has 1 to 30 carbon atoms. Is.
With such a structure, the transmittance of the i-line, which is a light source used at the time of patterning, becomes high.

The divalent organic group of U is preferably a group containing an aliphatic structure having 1 to 30 carbon atoms, and more preferably a group containing an aliphatic chain structure having 2 to 20 carbon atoms. The divalent organic group of U is preferably a group containing a structure represented by the following formula (UV1).
In the formula (UV1), R ¹ and R ² are independently hydrogen atoms, fluorine atoms, alkyl groups having 1 to 6 carbon atoms or fluorinated alkyl groups having 1 to 6 carbon atoms, and a is 1 to 30. It is an integer.

Examples of R ¹ and R ² include a methyl group and a trifluoromethyl group, and a trifluoromethyl group is preferable from the viewpoint of transparency of the polybenzoxazole precursor.
a is preferably an integer of 1-5.

Examples of the group containing the aliphatic structure of V include a structure derived from a dicarboxylic acid.
Examples of the raw material dicarboxylic acid include aliphatic dicarboxylic acids such as dodecanedioic acid and decanedioic acid (preferably 1 to 30 carbon atoms, more preferably 7 to 20 carbon atoms) and 2,2-bis (4-carboxyphenyl). -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (p-carboxyphenyl) propane, 5-tert-butylisophthalic acid and the like can be mentioned, and V is two carboxys from these. Corresponds to the group excluding the group.

The aliphatic structure of V has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

The polybenzoxazole precursor of the component (a) may have a structural unit other than the structural unit represented by the formula (1) as a part thereof. In this case, the ratio of the structural units represented by the formula (1) is preferably 50 mol% or more, more preferably 60 mol% or more, of all the structural units.
Examples of the structural unit other than the structural unit represented by the formula (1) include those in which V is derived from a diphenyl ether dicarboxylic acid derivative.

Since the polybenzoxazole precursor is usually developed in an alkaline aqueous solution, it is preferably soluble in an alkaline aqueous solution.
Examples of the alkaline aqueous solution include an organic ammonium aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, a metal hydroxide aqueous solution, and an organic amine aqueous solution. In general, it is preferable to use a TMAH aqueous solution having a concentration of 2.38% by mass. Therefore, the component (a) is preferably soluble in the TMAH aqueous solution.

In addition, one criterion that the component (a) is soluble in an alkaline aqueous solution will be described below. (A) The component is dissolved in an arbitrary solvent to prepare a solution, and then spin-coated on a substrate such as a silicon wafer to form a resin film having a film thickness of about 5 μm. This is immersed in any one of a tetramethylammonium hydroxide aqueous solution, a metal hydroxide aqueous solution, and an organic amine aqueous solution at 20 to 25 ° C. As a result, when it is dissolved to form a solution, it is determined that the component (a) used is soluble in an alkaline aqueous solution.

Regarding the molecular weight of the polybenzoxazole precursor of the component (a), the weight average molecular weight in terms of polystyrene is preferably 10,000 to 100,000, more preferably 15,000 to 100,000, and 20 More preferably, it is between 000 and 85,000. If the weight average molecular weight is less than 10,000, the solubility in an alkaline developer may become too high, and if it is more than 100,000, the solubility in a solvent decreases or the viscosity of the solution increases. Handleability may be reduced.
The weight average molecular weight can be measured by the gel permeation chromatograph method and can be determined by conversion using a standard polystyrene calibration curve.
The dispersity obtained by dividing the weight average molecular weight by the number average molecular weight is preferably 1.0 to 4.0, more preferably 1.0 to 3.0.

(Component (b): Cross-linking agent)
The cross-linking agent for the component (b) is a compound represented by the following formula (2).
In formula (2), R ₁ is a hydrogen atom or a group represented by -CH _2- O-R ₂ independently of each other. At least one of R ₁ is a group represented by -CH _2- O-R ₂ . R ₂ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, when R ₂ is plural, R ₂ may be the same or different.

The cross-linking agent of the component (b) reacts with the polybenzoxazole precursor even at a relatively low temperature in the step of applying, exposing and developing the positive photosensitive resin composition and then heat-treating the pattern resin film. (Crosslinking reaction) or the crosslinking agent itself polymerizes. Thereby, even when the resin composition is cured at a relatively low temperature, for example, 200 ° C. or lower, good adhesiveness, mechanical properties, chemical resistance and flux resistance can be ensured.

Of the plurality of R ₁ , some may be -CH _2- O-R ₂ , or all may be -CH _2- O-R ₂ . Preferably all _{R 1} is _{-CH 2 -O-R} 2.
The alkyl group having 1 to 6 carbon atoms R _2, and the like methyl, ethyl or butyl group.

The blending amount of the component (b) is preferably 5 parts by mass or more, more preferably 5 to 40 parts by mass, and further preferably 10 to 30 parts by mass with respect to 100 parts by mass of the component (a).

(Component (c): Photosensitizer)
The photosensitizer as a component (c) is a compound that generates an acid when irradiated with active light, and has a function of increasing the solubility of the light-irradiated portion in an alkaline aqueous solution.

Examples of the photosensitizer include a diazonaphthoquinone compound, an aryldiazonium salt, a diallyl iodonium salt, a triarylsulfonium salt and the like, and among them, the diazonaphthoquinone compound is preferable because of its high sensitivity.
The diazonaphthoquinone compound is a compound having a diazonaphthoquinone structure.

The diazonaphthoquinone compound can be obtained, for example, by subjecting o-quinonediazidosulfonyl chlorides to a condensation reaction of a hydroxy compound, an amino compound or the like in the presence of a dehydrochloric acid agent.

Examples of o-quinone diazide sulfonyl chlorides include 1,2-benzoquinone-2-diazide-4-sulfonyl chloride, 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride, and 1,2-naphthoquinone-2-diazide. -4-sulfonyl chloride or the like can be used.

Examples of the hydroxy compound include hydroquinone, resorcinol, pyrogallol, bisphenol A, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,3,4-trihydroxybenzophenone, and the like. 2,3,4,4'-tetrahydroxybenzophenone, 2,2', 4,4'-tetrahydroxybenzophenone, 2,3,4,2', 3'-pentahydroxybenzophenone, 2,3,4,3 ', 4', 5'-Hexahydroxybenzophenone, bis (2,3,4-trihydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) propane, 4b, 5,9b, 10-tetrahydro- 1,3,6,8-tetrahydroxy-5,10-dimethylindeno [2,1-a] inden, tris (4-hydroxyphenyl) methane, tris (4-hydroxyphenyl) ethane and the like can be used.

Examples of the amino compound include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 4,4'-diaminodiphenylsulfide. , O-Aminophenol, m-Aminophenol, p-Aminophenol, 3,3'-Diamino-4,4'-Dihydroxybiphenyl, 4,4'-Diamino-3,3'-Dihydroxybiphenyl, Bis (3-) Amino-4-hydroxyphenyl) propane, bis (4-amino-3-hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (4-amino-3-hydroxyphenyl) sulfone, bis (4-amino-3-hydroxyphenyl) 3-Amino-4-hydroxyphenyl) hexafluoropropane, bis (4-amino-3-hydroxyphenyl) hexafluoropropane and the like can be used.

The blending amount of the component (c) is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the component (a) in order to improve the sensitivity and resolution at the time of exposure. It is more preferably 1 to 30 parts by mass, further preferably 0.5 to 25 parts by mass, and particularly preferably 3 to 20 parts by mass.

((D) component: solvent)
As the component (d), γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether acetate, benzyl acetate, n-butyl acetate, ethoxyethyl propionate, 3-methylmethoxypropionate, N-methyl-2-pyrrolidone, Examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphorylamide, tetramethylene sulfone, cyclohexanone, cyclopentanone, diethyl ketone, diisobutyl ketone and methyl amyl ketone. Usually, there is no particular limitation as long as other components in the photosensitive resin composition can be sufficiently dissolved.

Among these, from the viewpoint of excellent solubility of each component and coating property at the time of resin film formation, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether acetate, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N , N-Dimethylacetamide, dimethyl sulfoxide is preferably used.

The content of the component (d) is not particularly limited, but is preferably 50 to 400 parts by mass, more preferably 100 to 300 parts by mass, and even more preferably 150 to 250 parts by mass with respect to 100 parts by mass of the component (a).

(Component (e): amine compound)
The component (e) is a compound represented by the following formula (3).
In formula (3), R ₃ is a hydrogen atom or a group represented by −R _4- W, respectively. At least one of R ₃ is a group represented by -R _4- W. R ₄ is an alkylene group having 1 to 3 carbon atoms, and when _{R 4} is plural, _{R 4} may be the same or different. W is a hydrogen atom, a hydroxyl group, or a monovalent organic group, and when there are a plurality of W, the W may be the same or different.

The amine compound of the component (e) appropriately suppresses the reaction between the polybenzoxazole precursor and the cross-linking agent in the step of applying the positive photosensitive resin composition and then heating and drying the photosensitive resin film. As a result, good solubility and photosensitive characteristics can be obtained even when a highly reactive cross-linking agent is used in the step of developing after exposing the dry photosensitive resin film.

Among the plurality of _{R 3,} part may be a _-R 4 -W, all may be _-R 4 -W. Preferably all _{R 3} is _-R 4 -W.
The alkylene group having 1 to 3 carbon atoms of R _4, chain are preferred, methylene chain, ethylene chain or a propylene chain, and the like.

Examples of the monovalent organic group of W include an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group, a trimethoxysilyl group, an ethoxydimethoxysilyl group, a diethoxymethoxysilyl group and a triethoxy group. Examples thereof include a trialkoxysilyl group such as a silyl group, a tripropoxysilyl group and a tributoxysilyl group, a phenyl group, an epoxy group and a glycidyl ether group. The trialkoxysilyl group is a group in which three alkoxy groups are bonded to silicon. The three alkoxy groups may be the same or different. The alkoxy group has preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms.

The molecular weight of the component (e) is preferably 50 to 350, more preferably 80 to 350. With such a molecular weight, it has good compatibility with the solvent and does not volatilize when the photosensitive resin film is heated and dried, so that it has the effect of suppressing the reaction between the polybenzoxazole precursor and the cross-linking agent. You can get enough.

The blending amount of the component (e) is preferably 0.3 parts by mass or more, more preferably 0.5 to 15 parts by mass, and 1 to 10 parts by mass with respect to 100 parts by mass of the component (a). Is even more preferable.

As the component (e), one type may be used alone, or two or more types may be used in combination. When a component (e) having a molecular weight of 300 or more is used alone, it is preferably 1 part by mass or more with respect to 100 parts by mass of the component (a).

The positive photosensitive resin composition of the present invention may contain a known coupling agent, dissolution accelerator, dissolution inhibitor, surfactant, leveling agent and the like other than the above components, if necessary.

The positive photosensitive resin composition of the present invention may essentially consist of the components (a), (b), (c), (d) and (e). For example, 80% by mass or more and 100% by mass or less (preferably 90% by mass or more and 100% by mass or less) of the positive photosensitive resin composition of the present invention may be the above component, and 95% by mass of the composition. % Or more and 100% by mass or less and 98% by mass or more and 100% by mass or less may be the above components. Further, the positive photosensitive resin composition of the present invention may consist only of the components (a), (b), (c), (d) and (e).

[Manufacturing method of pattern cured film]
The method for producing a pattern-cured film of the present invention includes a step of applying the above positive photosensitive resin composition on a substrate and drying it to form a photosensitive resin film, and a process of exposing the photosensitive resin film to a pattern to make a resin. It includes a step of forming a film, a step of developing the exposed resin film with an alkaline aqueous solution to form a pattern resin film, and a step of heat-treating the pattern resin film to form a pattern cured film.
Hereinafter, each step will be described.

(Photosensitive resin film forming process)
In this step, a positive photosensitive resin composition is applied onto a substrate and dried to form a photosensitive resin film.
Examples of the substrate include glass, semiconductors, metal oxide insulators such as TiO ₂ and SiO ₂ , silicon nitride, copper, and copper alloys. The coating method is not particularly limited, but it can be applied using a spinner or the like.

Drying can be performed using a hot plate, an oven, or the like. The heating temperature is preferably 100 to 150 ° C. The heating time is preferably 30 seconds to 5 minutes. Thereby, the photosensitive resin film can be obtained from the positive photosensitive resin composition.
The film thickness of the photosensitive resin film is preferably 5 to 100 μm, more preferably 8 to 50 μm, and even more preferably 10 to 30 μm.

(Exposure process)
In this step, the photosensitive resin film is exposed to the pattern through the mask.
Examples of the active light beam to be irradiated include ultraviolet rays including i-rays, visible light, radiation and the like, and i-rays are preferable. As the exposure apparatus, a parallel exposure machine, a projection exposure machine, a stepper, a scanner exposure machine and the like can be used.

(Development process)
By developing the resin film that has undergone the exposure step, a patterned resin film (patterned resin film) can be obtained. Generally, when a positive photosensitive resin composition is used, the exposed portion is removed with a developing solution.

An alkaline aqueous solution can be used as the developing solution, and examples of the alkaline aqueous solution include sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, tetramethylammonium hydroxide and the like. Tetramethylammonium hydroxide is preferred.
The concentration of the alkaline aqueous solution is preferably 0.1 to 10% by mass.

The development time varies depending on the type of polybenzoxazole precursor used, but is preferably 10 seconds to 15 minutes, more preferably 10 seconds to 5 minutes, and even more preferably 30 seconds to 4 minutes from the viewpoint of productivity.

Alcohols or surfactants may be added to the above developer. The amount added is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the developing solution.

(Heat treatment process)
By heat-treating the pattern resin film, a crosslinked structure can be formed between the functional groups of the component (a) or between the component (a) and the component (b), and a pattern cured film can be obtained. In addition, the polybenzoxazole precursor of the component (a) undergoes a dehydration ring closure reaction by the heat treatment step to obtain the corresponding polybenzoxazole.

The heating temperature is preferably 250 ° C. or lower, more preferably 120 to 250 ° C., and even more preferably 160 to 230 ° C. Within this range, damage to the substrate and the device can be suppressed to a small extent, the device can be produced at a high yield, and energy saving of the process can be realized. By using the positive photosensitive resin composition of the present invention, a cured film having excellent adhesiveness to various substrates can be obtained by heat treatment at 200 ° C. or lower, for example, 175 ° C.

The heating time is preferably 5 hours or less, more preferably 30 minutes to 3 hours. Within this range, the cross-linking reaction or the dehydration ring closure reaction can be sufficiently advanced. The heat treatment atmosphere may be in the atmosphere or in an inert atmosphere such as nitrogen, but a nitrogen atmosphere is preferable from the viewpoint of preventing oxidation of the patterned resin film.

Examples of the apparatus used in the heat treatment step include a quartz tube furnace, a hot plate, a rapid thermal annealing, a vertical diffusion furnace, an infrared curing furnace, an electron beam curing furnace, a microwave curing furnace, and the like.

[Manufacturing process of semiconductor devices]
Next, as an example of the method for manufacturing the pattern cured film according to the present invention, the manufacturing process of the semiconductor device will be described with reference to the drawings. 1 to 7 are schematic cross-sectional views illustrating a manufacturing process of a fan-out package having a multi-layer wiring structure, and represent a series of steps from a first step to a seventh step. FIG. 8 is a schematic cross-sectional view of a fan-out package having a UBM (Under Bump Metal) -free structure.

In these figures, the semiconductor substrate 1 such as a Si substrate having a circuit element (not shown) is covered with a protective film 2 such as a silicon oxide film except for a predetermined portion of the circuit element, and the first is on the exposed circuit element. The conductor layer 3 is formed.
A film such as a polyimide resin is formed on this as an interlayer insulating film 4 by a spin coating method or the like (first step, FIG. 1).

Next, a photosensitive resin layer 5 such as a rubber chloride type or a phenol novolac type is formed on the interlayer insulating film 4 by a spin coating method, and the interlayer insulating film 4 of a predetermined portion is exposed by a known method using this as a mask. The window 6A is provided as described above (second step, FIG. 2).

The interlayer insulating film 4 exposed to the window 6A portion is selectively etched by a dry etching means using a gas such as oxygen or carbon tetrafluoride to form the window 6B. Next, the photosensitive resin layer 5 is removed using an etching solution that corrodes the photosensitive resin layer 5 without corroding the first conductor layer 3 exposed from the window 6B (third step, FIG. 3). ).

Further, using a known method, the second conductor layer 7 is formed and electrically connected to the first conductor layer 3 (fourth step, FIG. 4). When forming a multi-layer wiring structure having three or more layers, the above steps are repeated to form each layer.

Next, the surface protective film 8 is formed as follows using the positive photosensitive resin composition of the present invention. That is, the resin composition of the present invention is applied by a spin coating method, dried, irradiated with light from a mask on which a pattern forming a window 6C is formed on a predetermined portion, and then developed with an alkaline aqueous solution to form a pattern resin film. To form. Then, this pattern resin film is heated to form a polybenzoxazole pattern cured film, that is, a surface protective film 8 (fifth step, FIG. 5). The surface protective film 8 (polybenzoxazole pattern cured film) has a function of protecting the conductor layer from external stress, α rays, and the like.

Further, usually, after forming a metal thin film on the surface of the surface protective film 8 by a sputtering treatment, a plating resist is formed according to the window 6C by a known method, and the exposed metal thin film portion is plated with UBM. A metal layer 9 called (Under Bump Metal) is deposited. Then, the plating resist is peeled off, and the metal foil film other than the formation region of the metal layer 9 is removed by etching to form the UBM (sixth step, FIG. 6). Further, an external connection terminal 10 called a bump is formed on the surface of the metal layer 9 (7th step, FIG. 7). The metal layer 9 is formed for the purpose of relaxing the stress acting on the bump 10 and for improving the electrical connection reliability.

In recent years, from the viewpoint of reducing manufacturing costs, in order to omit the step of forming such a metal layer 9 (UBM), a UBM-free structure has been proposed in which a window 6C is formed on the surface protective film 8 and then bumps 10 are directly formed. Has been done. In the UBM-free structure, it is preferable to form the second conductor layer 7 connected to the bump 10 thicker than usual in order to suppress an increase in electrical resistance due to the formation of an intermetallic compound. Further, it is preferable that the stress acting on the bump 10 is relaxed by the surface protective film 8. Therefore, it is preferable to cover the thickly formed second conductor layer 7 and to form the surface protective film 8 thickly in order to enhance the stress relaxation ability (FIG. 8). Therefore, in the UBM-free structure, when the window 6C is formed on the surface protective film 8, it is preferable to apply a thicker resin film, expose the film, and develop the window 6C.

[Electronic components]
Next, the electronic component of the present invention will be described. The electronic component of the present invention has a cured film obtained from the positive photosensitive resin composition of the present invention. For example, it is possible to have a pattern cured film obtained by the above method for producing a pattern cured film.

Specifically, a cured film such as a pattern cured film can be used as a surface protective film for electronic components, a cover coat layer, an interlayer insulating film, an interlayer insulating film for a multilayer wiring board, and the like.
Examples of electronic components include semiconductor devices, multilayer wiring boards, and various electronic devices. The above-mentioned semiconductor device is an embodiment of the electronic component of the present invention, but is not limited to the above, and may have various structures.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. The present invention is not limited to the following examples.

[(A) Synthesis of polybenzoxazole precursor]
In a 0.2 liter flask equipped with a stirrer and a thermometer, 60 g of N-methylpyrrolidone was charged, and 13.92 g (38 mmol) of 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was added. It was added and dissolved by stirring. Subsequently, 7.48 g (28 mmol) of dodecanedioic acid dichloride and 3.56 g (12 mmol) of 4,4'-diphenyl ether dicarboxylic acid dichloride were added dropwise over 10 minutes while maintaining the temperature at 0 to 5 ° C., and then in a flask. The solution was stirred for 60 minutes. The above solution was poured into 3 liters of water, the precipitate was collected, washed with pure water three times, and then reduced under reduced pressure to obtain a polyhydroxyamide (polybenzoxazole precursor) (hereinafter referred to as Polymer I). To do). The weight average molecular weight of Polymer I was 33,100 and the dispersity was 2.0. The weight average molecular weight was determined by gel permeation chromatography (GPC) method standard polystyrene conversion.

The measurement conditions of the weight average molecular weight by the GPC method are as follows. The measurement was carried out using a solution of 1 ml of a solvent [tetrahydrofuran (THF) / dimethylformamide (DMF) = 1/1 (volume ratio)] with respect to 0.5 mg of the polymer.
Measuring device: Detector L4000 manufactured by Hitachi, Ltd.
UV pump: L6000 manufactured by Hitachi, Ltd.
C-R4A Chromatopac manufactured by Shimadzu Corporation
Measurement conditions: Column Gelpack GL-S300MDT-5 × 2
This eluent: THF / DMF = 1/1 (volume ratio)
LiBr (0.03 mol / l), H ₃ PO ₄ (0.06 mol / l)
Flow velocity: 1.0 ml / min
Detector: UV270nm

Examples 1-12, Comparative Examples 1-4
[Preparation of photosensitive resin composition]
Each component was mixed with the components and blending amounts shown in Table 1 to prepare a photosensitive resin composition. The blending amount shown in Table 1 is the mass part of each component with respect to 100 parts by mass of the component (a).
The components used in Examples 1 to 12 and Comparative Examples 1 to 4 are as follows.

<Component (a): Polybenzoxazole precursor>
(A-1): Polymer I obtained by the above synthesis

<Component (b): Cross-linking agent>
(B-1): Acid-modified alkylated melamine formaldehyde having the following structure (manufactured by Allnex, trade name "Simel 300")

<Component (c): Photosensitizer>
(C-1): Compound having the following structure (manufactured by Daito Chemix Corp., trade name "TPPA428")

<(D) component: solvent>
BLO: γ-butyrolactone

<(E) component: amine>
(E-1): Compound having the following structure (manufactured by Gelest, trade name “SIB1140.0”)
(E-2): Trimethoxysilane having the following structure (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-903")
(E-3): Triethoxysilane having the following structure (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBE-903")
(E-4): 2-Dimethylaminoethanol (e-5): N, N-diethylethanolamine (e-6): N-methyldiethanolamine (e-7): N-ethyldiethanolamine

<(E') component>
(E'-1): Triethoxysilane having the following structure (manufactured by UCT, trade name "UCT-801")
(E'-2): Pyridine (e'-3): Trimethoxysilane having the following structure (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-803")

[Manufacturing of dry membrane]
The obtained photosensitive resin composition was spin-coated on a Si substrate and heated at 110 ° C. on a hot plate to form a coating film of 11.0 to 11.5 μm. The obtained coating film was subjected to reduced projection exposure on i-line (365 nm) using a mask with an i-line stepper (FPA-3000iW manufactured by Canon). The coating film after exposure was developed with a 2.38% aqueous solution of tetramethylammonium hydroxide, and developed so that the residual film thickness was about 70 to 80% of the initial film thickness.

[Evaluation of solubility in developer]
The film thickness after development was measured, and the dissolution rate per second was determined.
The case where the dissolution rate of the unexposed portion was 50 nm / s or more was evaluated as ⊚, the case of less than 50 nm / s to 15 nm / s or more was evaluated as ◯, and the case of less than 15 nm / s was evaluated as x. The results are shown in Table 1.

[Evaluation of photosensitive characteristics]
The developed film was observed with a microscope to determine the minimum exposure required for opening the pattern. The case where the pattern was opened at less than 300 mJ / cm ² was evaluated as ◯, and the case where the pattern was opened at 300 mJ / cm ² or more was evaluated as x. The results are shown in Table 1.
The pattern resin film was heat-treated to obtain a pattern cured film.

From Table 1, it can be seen that the dry film obtained from the positive photosensitive resin composition of the present invention is excellent in solubility in an alkaline developer and photosensitive characteristics.

1 Semiconductor substrate 2 Protective film 3 1st conductor layer 4 Interlayer insulating film 5 Photosensitive resin layer 6A, 6B, 6C Window 7 2nd conductor layer 8 Surface protective film 9 Metal layer 10 External connection terminal

Claims (10)

It contains (a) a polybenzoxazole precursor, (b) a cross-linking agent, (c) a photosensitizer, (d) a solvent, and (e) an amine compound.
The component (a) contains a structural unit represented by the following formula (1), the component (b) is a compound represented by the following formula (2), and the component (e) is the following formula (3). A positive photosensitive resin composition which is a compound represented by.
(In the formula (1), U is a divalent organic group, a single bond, -O- or -SO _2- , V is a group containing an aliphatic structure, and the aliphatic structure has 1 to 1 carbon atoms. 30.)
(In the formula (2), _{R 1} is each independently at least one of the .R ₁ is a group represented by hydrogen or _{-CH 2 -O-R} 2 is _{-CH 2 -O-R} 2 a is .R ₂ is group represented by a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, when R ₂ is plural, R ₂ may be the same or different.)
(In formula (3), R ₃ is a hydrogen atom or a group represented by -R _4- W, respectively. At least one of R ₃ is a group represented by -R _4- W. R ₄ is an alkylene group having 1 to 3 carbon atoms, and when R ₄ is plural, R ₄ may be the same or different. W is a hydrogen atom, a hydroxyl group or a monovalent organic group. When there are a plurality of Ws, the Ws may be the same or different, except that at least one of the Ws is a hydroxyl group or a trialkoxysilyl group. ) The positive photosensitive resin composition according to claim 1, wherein the component (b) is contained in an amount of 5 parts by mass or more with respect to 100 parts by mass of the component (a). The positive photosensitive resin composition according to claim 1 or 2, wherein the component (e) is contained in an amount of 0.3 parts by mass or more with respect to 100 parts by mass of the component (a). The positive photosensitive resin composition according to any one of claims 1 to 3, wherein the component (e) has a molecular weight of 50 to 350. The positive photosensitive resin composition according to any one of claims 1 to 4, wherein the component (c) is a diazonaphthoquinone compound. A step of applying the positive photosensitive resin composition according to any one of claims 1 to 5 onto a substrate and drying it to form a photosensitive resin film.
A step of exposing the photosensitive resin film to a pattern to form a resin film, and
A step of developing the exposed resin film with an alkaline aqueous solution to form a pattern resin film, and
A step of heat-treating the pattern resin film to form a pattern cured film, and
A method for producing a pattern cured film including. The method for producing a pattern cured film according to claim 6, wherein the heat treatment temperature is 250 ° C. or lower in the step of heat-treating the pattern resin film. A cured film obtained by curing the positive photosensitive resin composition according to any one of claims 1 to 5. An interlayer insulating film, a cover coat layer, or a surface protective film using the cured film according to claim 8. An electronic component having the interlayer insulating film, cover coat layer or surface protective film according to claim 9.