JPH1126579A - Manufacture of substrate having multilevel interconnection structure and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a substrate with high wiring reliability and stable adhesion, which can be easily manufactured, and which has a multilevel interconnection structure using a positive photosensitive resin composition realizing superior image formation, so as to approximately completely planarize the step of a lower wiring layer, and a semiconductor device with high wiring reliability, in which the step of a lower wiring layer is approximately completely planarized on an interlayer insulating film. SOLUTION: The method comprises formation of an interlayered insulating film using the positive photosensitive resin composition comprising (a) a complex of organic solvent soluble polyimide and basic compound, (b) photo-oxide generator and (c) solvent, on a substrate having a pattern-formed wiring layer, and forming an upper wiring layer on the interlayer insulating film. The device comprises complex of organic solvent soluble polyimide (a), a basic compound, a photooxide generator (b), and an interlayer insulating film formed by using the positive photosensitive resin composition (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing an electronic circuit board such as a semiconductor integrated circuit having a multilayer wiring structure, a high-density mounting board, and a semiconductor device.

[0002]

In the manufacture of multi-layer wiring structure in a semiconductor integrated circuit, a vacuum vapor deposition on a substrate having a wiring layer formed in the pattern, SiO _2, SiN by vapor deposition such as CVD (chemical vapor a deposition) A method is used in which an interlayer insulating film made of the same is formed, a through hole is opened, and then an upper wiring layer is formed. However, in the method of forming the interlayer insulating film by the vapor phase growth method, as shown in FIG. 7, the step of the lower wiring layer 4 remains as it is even after the formation of the interlayer insulating layer 5, and when the upper wiring layer 7 is formed, There is a problem that the wiring layer becomes extremely thin at the step portion and the wiring is liable to be cut. FIG. 7 is a cross-sectional view showing a multilayer wiring structure in which an interlayer insulating film is formed by a vapor growth method, wherein 1 is a semiconductor substrate, and 2 is a silicon dioxide film.
In order to improve this, as shown in FIG. 5, the interlayer insulating film 5 is formed by applying a solution of a polyamic acid obtained from an aromatic diamine and an aromatic tetrabasic dianhydride,
A method using a polyimide obtained by curing is proposed,
At present, it is widely used (JP-B-51-44871).

On the other hand, when polyimide is used, the film processing is performed by an etching process using a photoresist. Therefore, recently, a photosensitive polymer composition combining the functions of a photoresist has been used for the purpose of streamlining the film processing process. The development of products is under consideration. Various types of photosensitive polyimides have been proposed, but a negative type in which an unexposed portion is removed by a developing process and an exposed portion remains as a pattern, and a non-exposed portion in which the exposed portion is removed by a developing process. It is broadly divided into positive patterns that remain as patterns. As the negative type, for example, JP-A-49-11541
JP, JP-A-50-40922, JP-A-54-922
JP-A-145794 and JP-A-56-38038 propose a method of providing an acryloyl group as a photosensitive group to an polyimide precursor via an ester bond or an ionic bond. In general, the negative type is problematic in terms of environment and safety because it is difficult to increase the resolution in principle and uses a large amount of an organic solvent as a developer.

On the other hand, in the positive type, an alkaline aqueous solution is generally used as a developing solution, and since the positive type can be expected to have high resolution in principle, attention has been paid to the positive type photosensitive polyimide. I have. Examples of the positive photosensitive polyimide include, for example, Japanese Patent Publication No. 64-63030.
No. 4,395,482, JP-A-52-1331.
No. 5, JP-A-4-120171 and the like, soluble polyimide having a hydroxyl group, a polyoxazole precursor,
A method of adding naphthoquinonediazide to a polyimide precursor and a method of adding a photoacid generator to a polyimide precursor having a carboxyl group protected have been proposed. However, these have problems such as large film loss due to high-temperature treatment after development, poor viscosity stability or low efficiency of protecting group removal, and in fact, none of them have reached the practical level. is there.

[0005]

The invention according to claims 1 and 2 uses a positive photosensitive resin composition which is easy to produce, has excellent viscosity stability, and can form a good image. An object of the present invention is to provide a method for manufacturing a substrate having a multilayer wiring structure in which steps of a wiring layer can be almost completely flattened and wiring has high reliability. According to a third aspect of the present invention, there is provided a semiconductor device in which a step of a lower wiring layer in an interlayer insulating film is almost completely flattened and wiring has high reliability.

[0006]

According to the present invention, there is provided a method comprising the steps of: (a) forming a complex formed from an organic solvent-soluble polyimide and a basic compound on a substrate having a patterned wiring layer;
(B) forming an interlayer insulating film using a positive photosensitive resin composition containing a photoacid generator and (c) a solvent, and forming an upper wiring layer thereon; The present invention relates to a method for manufacturing a substrate having a multilayer wiring structure.

The present invention also relates to a method for manufacturing a substrate having a multilayer wiring structure in which the above steps are repeated two or more times. The present invention further provides a positive photosensitive resin composition containing (a) a complex formed from an organic solvent-soluble polyimide and a basic compound, (b) a photoacid generator, and (c) a solvent. The present invention relates to a semiconductor device having an interlayer insulating film formed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a substrate having a wiring layer on which a pattern is formed includes, for example, a silicon semiconductor substrate on which an aluminum wiring layer is formed, a ceramic high-density mounting substrate on which a copper wiring layer is formed, and a copper wiring. Refers to a ceramic hybrid substrate or the like on which a layer is formed. In the production method of the present invention, a positive photosensitive resin composition is applied to a substrate having a wiring layer on which the pattern is formed, by dipping, spraying, screen printing, spin coating, or the like,
Then, by heating and drying, a coating film having no tackiness can be obtained.

Here, the positive photosensitive resin composition used in the present invention will be described. In the positive photosensitive resin composition used in the present invention, an organic solvent-soluble polyimide is used in order to form a complex of the polyimide and the base compound in an organic solvent. The organic solvent-soluble polyimide to be used may be selected from those soluble in any of the organic solvents. However, in order to be sufficiently soluble, a resin solid content concentration of 10
It is preferable to have a solubility that can be a solution by weight or more. Polyimide has the following general formula (I)

Embedded image (Wherein, R ¹ represents a tetravalent aromatic group, an alicyclic group or an aliphatic group, R ² represents a divalent aromatic group, an alicyclic group or an aliphatic group, and these groups are (Which may be substituted by a substituent such as an alkyl group, a halogen group, a nitro group, and a sulfone group).

This polyimide can be obtained by heating and ring closing a polyimide precursor obtained from a reaction between equimolar tetracarboxylic dianhydride and diamine in an organic solvent. Here, the tetracarboxylic dianhydride and the diamine used are selected so that the obtained polyimide becomes soluble in an organic solvent. When the polyimide precursor is heat-closed, it is preferable to add a solvent such as xylene to azeotropically generate water generated by imidization. At this time, a basic catalyst or the like for promoting imidization can be added.

The above tetracarboxylic dianhydride includes:
For example, oxydiphthalic dianhydride, pyromellitic dianhydride, 3,3,4,4-benzophenonetetracarboxylic dianhydride, 3,3,4,4-biphenyltetracarboxylic dianhydride, 1,2 2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,5 6,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, sulfonyldiphthalic dianhydride, m-terphenyl-3,3,4,4-tetracarboxylic acid Acid dianhydride, p-terphenyl-3,3,4,4-tetracarboxylic dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis (2,3- Or 3,4-dicarboxyphenyl ) Propane dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis {4- (2,3- or 3,4
-Dicarboxyphenoxy) phenyl} propane dianhydride, 1,1,1,3,3,3-hexafluoro-2,2
-Bis {4- (2,3- or 3,4-dicarboxyphenoxy) phenyl} propane dianhydride, having the following general formula (I
I)

Embedded image (R ³ and R ⁴ each represent a monovalent hydrocarbon group, and may be the same or different, and s is an integer of 1 or more), such as a tetracarboxylic dianhydride having a siloxane structure. Preferred are aliphatic tetracarboxylic dianhydrides, which are used alone or in combination of two or more.

The diamine is not particularly restricted but includes 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl and 2,2 '. , 6,6'-Tetramethyl-4,4 '
-Diaminobiphenyl, 3,3 ', 5,5'-tetramethyl-4,4'-diaminobiphenyl, 4,4- (or 3,4-, 3,3-, 2,4-, 2,2- ) Diaminodiphenyl ether, 4,4 (or 3,4-, 3,3-,
2,4-, 2,2-) diaminodiphenylmethane, 4,
4- (or 3,4-, 3,3-, 2,4-, 2,2-)
Diaminodiphenyl sulfone, 4,4- (or 3,4
-, 3,3-, 2,4-, 2,2-) sulfide, 3,
3-diaminodiphenyl sulfone and paraphenylenediamine, metaphenylenediamine, p-xylylenediamine, m-xylylenediamine, o-tolidine, o-tolidinesulfone, 4,4-methylene-bis- (2,6-
Diethylaniline), 4,4-methylene-bis- (2,
6-diisopropylaniline), 2,4-diaminomesitylene, 1,5-diaminonaphthalene, 4,4-benzophenonediamine, bis- {4- (4-aminophenoxy) phenyl} sulfone, 1,1,1,3, 3,3-hexafluoro-2,2-bis (4-aminophenyl) propane, 2,2-bis {4- (4-aminophenoxy)
Phenyl} propane, 3,3-dimethyl-4,4-diaminodiphenylmethane, 3,3,5,5-tetramethyl-4,4-diaminodiphenylmethane, bis {4- (3
Preferred are aromatic diamines such as -aminophenoxy) phenyl} sulfone and 2,2-bis (4-aminophenyl) propane, and these are used alone or in combination of two or more.

In order to improve the adhesion and the like, the following general formula (III)

Embedded image (Wherein, R ⁵ and R ⁶ represent a divalent hydrocarbon group, R ⁷ and R ⁸ represent a monovalent hydrocarbon group, and a plurality of R ⁷ and R ⁸ may be the same or different. , T is an integer of 1 or more), or an aliphatic diamine such as diaminopolysiloxane.

A complex of a polyimide and a basic compound can be produced by adding a basic compound to the above-mentioned organic solvent-soluble polyimide and stirring and mixing at room temperature. It is considered that this complex is formed by coordinating a basic compound to the carbonyl group of the polyimide. The basic compound is not particularly limited, and a generally known basic compound can be used. Preferred are a monoalkylamine having an alkyl group having 1 to 15 carbon atoms, a dialkylamine having an alkyl group having 1 to 8 carbon atoms, and a trialkyl having an alkyl group having 1 to 6 carbon atoms. Amines such as amines, having 1 to 6 carbon atoms
(Metals include sodium, potassium, calcium, and aluminum). Specifically preferred examples of the monoalkylamine include monomethylamine, monoethylamine, monopropylamine, monobutylamine, and monohexylamine.
Examples of the dialkylamine include dimethylamine, diethylamine, dipropylamine, and dihexylamine.Examples of the trialkylamine include trimethylamine, triethylamine, tripropylamine, tributylamine, and trihexylamine.Examples of the alkoxide include sodium methoxide and potassium methoxy. , Sodium ethoxide, potassium ethoxide and the like.

The amount of the basic compound used for forming the complex is not particularly limited, but is a repeating unit represented by the above general formula (I) showing the structure of the polyimide, ie, 2 units of the polyimide.
It is preferable to use an amount in which the number of molecules of the basic compound is in the range of 0.2 to 20, with the total number of repeating units having one repeating unit containing one imide bond as one unit. More preferably, an amount of 5 to 15 is used.

As the organic solvent used for the production of the polyimide, the complex formation and the production of the photosensitive composition, a polar solvent which completely dissolves the polyimide is generally preferable, and among them, an aprotic polar solvent is more preferable. Specific preferred compounds include -methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, tetramethylurea, hexamethylphosphoric triamide, γ-butyrolactone, cyclohexanone, and the like.

Other than the polar solvent, ketones,
Esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate , Diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4
-Dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like can also be used. These are preferably used in combination with the above-mentioned polar solvent, and in that case, the content is preferably not more than 80% by weight based on the total amount of the solvent.

The amount of the solvent in the photosensitive resin composition is not particularly limited, but is preferably from 1 to 80% by weight based on the total amount of the polyimide and the polyimide, from the viewpoints of viscosity, coatability, and the like. , More preferably 10 to 50% by weight, particularly preferably 15 to 40% by weight.

The photoacid generator used in the photosensitive resin composition has a function of generating an acid upon irradiation with light, and is not particularly limited, and a generally well-known photoacid generator is used. be able to. For example, triphenylsulfonium hexafluoroantimonate, nitrobenzyl tosylate, hydroxybenzophenone methanesulfonate ester, diaryliodonium salt, diphenyl-4-thiophenoxyphenylsulfonium salt, 2,
Preferred compounds include 4,6- (trichloromethyl) triazine and tris (2,3-dibromopropyl) isocyanurate. From the standpoint of photosensitivity, the amount is preferably 0.2 to 30, with the total number of repeating units represented by the general formula (I) indicating the structure of polyimide being 1, and 0.5 to 0.5. More preferably, it is set to 20.

In the photosensitive resin composition, a photosensitizer can be used, if necessary, in addition to the photoacid generator. The photosensitizer is not particularly limited, and examples thereof include Michler's ketone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, 2-t
-Butyl anthraquinone, 2-ethylanthraquinone,
4,4-bis (diethylamino) benzophenone, acetophenone, benzophenone, thioxanthone, 2,2
-Dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-
[4- (methylthio) phenyl] -2-morpholino-
1-propanone, benzyl, diphenyl disulfide,
Phenanthrenequinone, 2-isopropylthioxanthone, riboflavin tetrabutyrate, 2,6-bis (p
-Diethylaminobenzal) -4-methyl-4-azacyclohexanone, N-ethyl-N- (p-chlorophenyl) glycine, N-phenyldiethanolamine, 2-
(O-ethoxycarbonyl) oxyimino-1,3-diphenylpropanedione, 1-phenyl-2- (o-ethoxycarbonyl) oxyiminopropan-1-one,
3,3,4,4-tetra (t-butylperoxycarbonyl) benzophenone, 3,3-carbonylbis (7-
Diethylaminocoumarin), bis (cyclopentadienyl) -bis- [2,6-difluoro-3- (pyri-1-
Yl) phenyl] titanium and the like. These are used alone or in combination of two or more. When these are used, their amounts are not particularly limited, but are preferably 0.001 to 10% by weight based on the total amount of polyimide.

The photosensitive resin composition is applied onto the above-mentioned base material by a method such as a silicon wafer, a metal substrate, a ceramic substrate or the like by a dipping method, a spray method, a screen printing method, a spin coating method or the like, and a solvent is removed. By heating and drying appropriately, a coating film having no tackiness can be obtained. The coating film is irradiated with actinic rays or actinic rays through a mask on which a desired pattern is drawn. The actinic rays or actinic rays to be irradiated include a contact / proximity exposure machine using an ultra-high pressure mercury lamp, a mirror projection exposure machine, an i-ray stepper, a g-ray stepper, other ultraviolet rays, a visible light source,
X-rays and electron beams can be used. After the irradiation, a through hole is formed by dissolving and removing the irradiated portion with a developing solution.

As the developing solution, a basic solution such as an aqueous solution of tetramethylammonium hydroxide or an aqueous solution of triethanolamine is preferable. In addition, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-
A good solvent such as 2-pyrrolidone or a mixed solvent thereof with a poor solvent such as lower alcohol, water or aromatic hydrocarbon can also be used. . Next, by heating at a temperature of 100 to 500 ° C., preferably 120 to 400 ° C. for several tens of minutes to several hours, an interlayer insulating film, which is a polyimide resin film from which the photosensitive agent and the solvent have been completely removed, is formed. The step can be flattened at a specific portion of the surface. At the time of the above-mentioned film formation, it is also possible to add an adhesion auxiliary agent such as aminosilane or epoxysilane to the photosensitive resin composition, if necessary, for the purpose of increasing the adhesion to the substrate surface.

An upper wiring layer is vacuum-deposited, sputtered, and CVD on the interlayer insulating film in which the through-hole is formed.
(Chemical vapor deposition) and the like can be used. As a result, a multilayer wiring structure is formed. By further patterning the upper wiring layer and repeating the above manufacturing method twice or more, a substrate having a wiring structure in which the wiring layer and the insulating layer are more multilayered can be obtained. . The semiconductor device of the present invention has an interlayer insulating film formed by using the positive photosensitive resin composition. This semiconductor device usually has a multilayer wiring structure formed by the above-described method for manufacturing a multilayer wiring structure.

[0024]

【Example】

a. Production of photosensitive resin composition In a three-necked flask equipped with a stirrer, a thermometer and a nitrogen inlet tube, 73.3 g of 4,4, -methylene-bis (2,6-diisopropylaniline) and 500 g of N-methyl-2-pyrrolidone were placed. Was added and stirred and dissolved at room temperature under a stream of nitrogen. To this solution was added 43.6 g of pyromellitic dianhydride, and 5
After stirring for a time, a polyimide precursor solution was obtained. 150 g of xylene was added to this polyimide precursor solution,
After heating for an hour, the remaining xylene was distilled off under reduced pressure to obtain a polyimide solution. Further, 14.6 g of diethylamine was added and stirred at room temperature for 3 hours to obtain a polyimide-amine complex solution. 1.6 g of triphenylsulfonium hexafluoroantimonate as a photoacid generator was added to 10 g of the obtained polyimide-amine complex solution, and the mixture was stirred and mixed, and then filtered to obtain a photosensitive resin composition.

B. 1. Fabrication of Semiconductor Device Having Multilayer Wiring Structure As shown in FIG.
CVD (Chemical Vapor Deposition) is applied to the surface of the semiconductor substrate 1 on which the semiconductor element composed of the semiconductor region
As a result, a silicon dioxide film 2 was formed. Next, a predetermined portion serving as an electrode lead-out portion was removed by etching by a usual photolithography process, a via hole (window) 3 was provided in the silicon dioxide film, and a part of the emitter region and the base region was exposed. Further, an aluminum wiring layer was formed on the via hole by a sputtering method, and a photolithography process was performed to form a lower wiring layer 4. This wiring layer has a thickness of 1 μm and a thickness of 0.5 μm.
It had a width of ２2 μm.

Next, the photosensitive resin composition of the above a was spin-coated on the lower wiring layer (FIG. 2), heated at 80 ° C./60 seconds using a hot plate, and then using an ultra-high pressure mercury lamp through a photomask 6. To expose (exposure amount: 1000 mJ / cm ² ) (FIG. 3). Next, when developed with an aqueous solution of tetramethylammonium hydroxide, an exposed portion was dissolved, and a good positive pattern in which an unexposed portion remained was obtained. Next, it was cured at 350 ° C. for 1 hour in a convection oven to obtain a polyimide interlayer insulating film 5 having a thickness of 2 μm (FIG. 4). Thereafter, an upper aluminum wiring layer 7 was formed by a sputtering method, and a semiconductor device having a two-layer wiring structure shown in FIG. 5 was obtained. In FIG. 5, reference numeral 5 denotes a polyimide interlayer insulating film.

C. Evaluation of flattening rate and embedding property The flattening rate of the initial step by the polyimide film thus obtained was measured by the values of a and b shown in FIG.

(Equation 1) Was about 90%. Further, when the silicon substrate was cut at the groove pattern portion and the cross-sectional shape was observed with a scanning electron microscope, it was found that all the grooves were sufficiently filled with the polyimide resin.

D. Evaluation of Developing Processability The photosensitive resin composition of the present invention was spin-coated on a silicon substrate at the same film thickness as described above, and 80
The film was heated at 60 ° C. for 60 seconds, and exposed to light (exposure amount: 1000 mJ / cm ² ) through a photomask using an ultra-high pressure mercury lamp. Next, when developed with an aqueous solution of tetramethylammonium hydroxide, an exposed portion was dissolved, and a good positive pattern in which an unexposed portion remained was obtained.

Comparative Example A photosensitive resin composition was obtained in the same manner as in the example except that diethylamine added to the polyimide solution was not added. Hereinafter, in the same manner as in the example, the step flattening rate, the embedding property of the groove pattern, the development workability, and the film state after development were evaluated. As a result, the flattening rate was 90% and the embedding property was also good. However, when the development workability was evaluated in the same manner as in the example, there was no difference in the dissolution time between the exposed part and the unexposed part. Was not made.

[0030]

According to the production method according to claims 1 and 2,
Since the step of the lower wiring layer can be almost completely flattened by the interlayer insulating film by using a photosensitive resin composition process that does not require a resist coating process, the reliability of the wiring is almost completely eliminated due to the multilayer wiring. A substrate having a multi-layered wiring structure having a remarkably superior multilayer wiring structure can be obtained. According to a third aspect of the present invention, the step in the lower wiring layer is almost completely flattened by the interlayer insulating film, and the wiring is excellent in reliability with almost no step due to the multilayer wiring.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor device having a lower wiring layer.

FIG. 2 is a cross-sectional view showing a state where a photosensitive resin composition is applied on a semiconductor device having a lower wiring layer.

FIG. 3 is a cross-sectional view showing a state in which the photosensitive resin composition has been exposed through a photomask.

FIG. 4 is a cross-sectional view showing a state after a step of forming a polyimide insulating layer has been completed.

FIG. 5 is a cross-sectional view of a semiconductor device having a two-layer wiring structure planarized by a polyimide insulating layer.

FIG. 6 is a diagram showing a method for evaluating a flattening rate in an example of the present invention.

FIG. 7 is a cross-sectional view of an example of a conventional multilayer wiring structure in which an SiO ₂ film formed by a vapor deposition method is used as an interlayer insulating film.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor substrate 2 silicon dioxide film 3 via hole (window) 4 lower wiring layer 5 interlayer insulating film 6 photomask 7 upper wiring layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/46 H05K 3/46 BT

Claims (3)

[Claims] 1. A substrate having a wiring layer on which a pattern is formed, comprising: (a) a complex formed by an organic solvent-soluble polyimide and a basic compound; (b) a photoacid generator; and (c) a solvent. A method of manufacturing a substrate having a multilayer wiring structure, comprising the steps of forming an interlayer insulating film using the positive photosensitive resin composition thus formed, and forming an upper wiring layer thereon. 2. A method for manufacturing a substrate having a multilayer wiring structure in which the step according to claim 1 is repeated two or more times. 3. A positive photosensitive resin composition comprising (a) a complex formed of an organic solvent-soluble polyimide and a basic compound, (b) a photoacid generator and (c) a solvent. A semiconductor device having the formed interlayer insulating film.