JPS62283699A - Manufacture of multilayer interconnection board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a multilayer wiring board, and is particularly applicable to printed circuit boards such as computers that require high-density packaging, and LSI The present invention relates to a method for economically manufacturing a multilayer board used for circuit modules and the like for mounting with high performance and high reliability.

[Conventional technology]

Conventionally, circuit boards used in computers, communication equipment, etc. have been made of glass fiber impregnated with epoxy resin or polyimide resin, with copper foil on both sides.
Furthermore, there is a multilayer printed circuit board in which a conductor pattern layer is also provided on the inner layer to increase the wiring density, and the conductor patterns in each layer are connected by through-hole plating. Alternatively, a thick film wiring board with a metal pattern layer formed by a printing method on the surface of an inorganic insulating substrate such as alumina ceramic or glass, or a method such as plating or vapor deposition on the surface of a resin base material or inorganic insulating substrate. A so-called thin film wiring board in which a metal pattern layer is formed is used.

In these methods, holes are made by drilling or punching in the insulating layer for connection between the top and bottom of the conductor pattern layer, and the holes are then filled with plating or a conductive material. However, ultra-high-density wiring has become difficult due to the limits of miniaturization of drill diameters and punching pins.

In recent years, there has been a high demand for ultra-high-density wiring technology for high-speed calculations in ultra-large computers, and in response to this demand, we have applied dry etching and wet type 1/notching techniques used in LSI to form insulating layers and via holes (through holes). However, due to the complexity of the process, the manufacturing cost is extremely high, making it difficult to put it into practical use. or,
Since the wet type 1 notching method uses photoresist to etch the insulating layer, it can only form via holes with a taper angle of approximately 45°, and has the disadvantage that the diameter of the via hole depends on the thickness of the insulating layer. For example, in order to secure a small diameter of 20 μm for an insulating layer with a thickness of 20 μm, the large diameter must be 60 μm, which is an impediment to high-density packaging.

In order to solve this drawback, attempts have been made to use photoresist as it is as an insulating layer.
It is disclosed in Japanese Patent No. 19695. However, since the heat resistance of the disclosed resin is low, it cannot withstand the heat applied when LSI is mounted, and has the drawback of lacking reliability.

Furthermore, it is easily conceivable to use a photosensitive polyimide precursor to impart heat resistance to the photoresist.

However, when the photosensitive polyimide precursor described in JP-A-54-145794 and JP-A-57-168942 is used, the viscosity of the polymer solution becomes high, so it is not suitable for multilayer substrates for LSI mounting. 10cr required
It is not easy to obtain a film thickness of m or more, which is inappropriate.

Also, Special Publication No. 55-30207, Special Publication No. 55-41
When the photosensitive polyimide precursor described in JP-A-422, JP-A-59-219330, etc. is used as an insulating layer of a multilayer wiring board, a highly heat-resistant insulating layer having a high density of via holes can be easily created. Although it can be formed, the patent application
According to the method for manufacturing a multilayer wiring board described in Publication No. 2494, especially when the wiring layer is formed of copper or gold, the wiring layer may peel off from the insulating layer because the adhesive strength between copper, gold, and polyimide is low. However, it has the problem that it is easy to use and lacks reliability.

Furthermore, when two or more conductor layers are formed of copper, the lower conductor layer is likely to be oxidized by oxygen in the atmosphere, especially in the via hole portion, which poses a problem in the process of heat-treating the photosensitive polyimide to make it highly insulative. Furthermore, even under normal usage environments, exposed copper wiring may be oxidized by moisture and oxygen in the atmosphere, so sufficient reliability cannot be achieved. [Problems to be Solved by the Invention] ] The present invention eliminates the above-mentioned drawbacks, and provides a wiring board suitable for high-density mounting, which enables the formation of extremely small-diameter Zumaia holes with high accuracy and the efficient formation of a multilayer wiring board with excellent reliability. The purpose is to share the manufacturing method.

[Means for solving problems]

Therefore, the present invention provides (a) a step of forming seven conductive turns on the surface of a base substrate (conductive layer forming step), (b) a step of forming X in the general formula (I) 3 on the conductive layer. <2+n)fi a group capable of forming a ring, n is 1 or 2, m
is Oll or 2, and C0OR and Z are in the ortho or peri position relationship with each other] or the general formula (n) [wherein the person in the formula is 4 (i [carbocyclic group or hetero represents a cyclic group, and B represents a divalent carbocyclic group or a heterocyclic group.] A photocrosslinkable polymer layer having a repeating unit represented by is provided, and light is applied onto the layer through a photomask. irradiation, forming a via hole by the phenomenon, and then heat-treating the layer to make it highly insulating (insulating layer forming step); (d) further forming a gold conductor circuit on the surface of the underlying layer, which is electrically connected to the conductive pattern in the lower layer through the via hole; The present invention relates to a method for manufacturing a multilayer wiring board characterized by comprising a connecting step (wiring layer forming step).

The conductive layer forming process of the present invention includes an alumina ceramic plate,
Plating or vapor deposition on the surface of a base substrate selected from glass plates, metal plates such as aluminum or iron insulated with resin or enamel, glass cloth-based epoxy substrates, glass cloth-based polyimide substrates, polyimide films, etc. This is a process in which a conductive pattern of copper, silver, gold, aluminum, molybdenum, etc. is formed by a method such as a method, a sputtering method, a screen printing method, or a pressure bonding method.

Specifically, the conductor is formed by cleaning the underlying substrate with a cleaning agent selected from organic solvents, acids, or aqueous alkaline solutions, or by plasma etching using a gas containing oxygen, carbon tetrafluoride, etc. Clean. Thereafter, a sputtering device is used to deposit a single layer or multiple layers on the base substrate using a metal selected from chromium, copper, gold, nickel, aluminum, etc. as a target. When sputtering is used, the adhesive strength between the base substrate and the conductor is excellent. It is also possible to form a conductor on the underlying substrate by vapor deposition. Furthermore, it is also possible to increase the thickness of the conductor by depositing a conductive metal such as gold on the conductor layer by electroplating or the like. An excellent method in terms of process is to form a nickel, copper or gold layer on the base substrate by electroless plating, and then
A method of forming a conductive pattern by a pattern plating method using a Menki resist may be mentioned.

Furthermore, cost-effective methods include a method of laminating metal foil such as copper foil and forming a pattern by chemical etching, and a method of printing a conductive material by screen printing to form a pattern.

In this conductive layer forming step, it is also possible to form a functional circuit by forming an abrasive pattern or a capacitor pattern using not only a conductor but also a paste commonly called thick film ink.

Further, a protective layer may be formed on the conductive layer if necessary.

In other words, because the photosensitive polyimide precursor has a high ultraviolet absorption rate, if the conductive layer is based on a metal with low reflectivity such as copper, the shape of the via hole will become a reverse taper (hangover) after exposure and development. This easily occurs and becomes an obstacle when forming a wiring layer.

+N metals include chromium, chromium gold, molybdenum, tungsten, aluminum, titanium, palladium,
Examples include platinum and nickel.

Formation methods include, for example, base deposition method, sputtering method, CV
Examples include D method, electrolytic flexible method, electroless plating method, and the like.

Using these methods, a protective layer with a thickness of 10 angstroms to 10 microns can be formed on the conductive layer by a normal photolithography technique.

The insulating layer forming step of the present invention is a step of forming fine via holes using a photocrosslinkable polymer as an insulating layer. This will be explained in more detail below.

First, if necessary, a polymer having a repeating unit represented by general formula (1) or general formula (n) Oo with an ultraviolet absorption peak wavelength of 300 to 300, such as Michler's ketone, is added.
Add a sensitizer at 500 nm and dissolve dimethylformamide, N-methylpyrrolidone, etc. J & Co., Ltd., coat it on the substrate on which the conductive layer is formed using a coating machine such as a spin coater, roll coater 1 or screen printer, and remove the solvent using a hot air dryer, hot plate, etc. to form a coating film.

Next, using a photomask, the parts other than the via holes are irradiated with ultraviolet rays and cured. Preferably, heat treatment is then applied as described in Japanese Patent Application No. 60-6613. This heat treatment further crosslinks the photocured portion, making it difficult to swell in the developer, resulting in a high-density pattern after development.

The temperature is preferably 50°C to 140°C, preferably a temperature at which the unexposed areas do not gel. The time is preferably 1 second to 1 hour.
More preferably, the time is 5 minutes to 20 minutes. Next, the unexposed areas are developed and removed using a developing solution such as γ-butyrolactone or N-methylpyrrolidone, or a rinsing solution such as isopropyl alcohol or xylene to form a via hole, and a heat-resistant Forms an excellent insulating layer.

In a polymer having a repeating unit represented by the general formula (1), X in the formula is a carbocyclic group or a heterocyclic group of 3 or 4 (il [i), and such X is For example, fused polycyclic aromatics such as benzene rings, naphthalene rings, anthracene rings, heterocyclic groups such as pyridine and thiophene,
and general formula (■,)'n-X, -=: red (I
II) 1 is O or 1, X2 is CH3, or CFs], and the like.

Among these, aromatic hydrocarbon groups having 6 to 14 carbon atoms,
l is −fCHぢ (l is 0 or 1), CF.

A group represented by formula (1) is preferable, and Y in the above general formula (1) is 2.3 or 41i1
5 carbocyclic or heterocyclic group, such as 21i! having a carbon number of 10 to 1 day derived from naphthalene, anthracene, etc. [i aromatic hydrocarbon group ring, heterocyclic group derived from pyridine, imidazole, etc. and formula 13 Y,
Y4 Y number [Yl in the formula is H,
CHs, (CH3)CH,0CHs, C○OH, halogen atom or SO3H, Yz is +CH2 base (however, p is O or 1), -8O, -2H3CF.

Y3 and 4 are H, CH3, CzHlI, OC)b,
Halogen atom, C00HSSO, H or NO2, '1'
11 and Y6 are HlCN, halogen atom, CH3,
OCH3, S03H or haOH] and the like. Among these, carbon number 1
0 to 14 divalent aromatic hydrocarbon ring, Y2 is -SO
, -1-〇- or -3-, a group represented by the formula (&) in which both Y3 and the blind are hydrogen atoms is preferred, and a group represented by the formula is more preferred.

Further, as a group having a reactive carbon-carbon double bond used as R, for example, OR"OHOR'R" CH= CHz (I[
Ig)OR' [In the formula, Ro is a hydrogen atom or a methyl group, R'' has 1 carbon number
to 3 alkylene groups, n represents 1 or 2. ] Examples of (L) include -CH2-CH2-0-C-CH=CH.

CH3 (As an example of ω, -CH, -O-CH) As an example of -CH, -CH, -CXCH-C8 (IIl,), OHO As an example of (■,), -CH2 -CH-C)4-CHz -CHz-CH-CH2 (-) Examples include 0CHa-CH, -CH, -NH-C-CH=CH2, and the like.

W in the general formula (I) can be converted to ROH (
R has the same meaning as above), -
A group capable of forming a ring by reacting with the carbonyl group of COOR, such as -C-N H2
A<suitable. Moreover, as n, 2 is preferable.

The polymer represented by the general formula (n) is, for example,
-138763, Mei II of patent application No. 61-33449
Examples include photosensitive polyimides described in Book I.

In formula (II), A has 6 to 20 carbon atoms.
is preferably an aromatic hydrocarbon group or a group represented by the structural formula xb.

0 CF3- Among these, the groups shown below are particularly preferred.

-5-1-〇-1-5-, R1 and R3 each represent an alkyl group having 1 to 6 carbon atoms, and R2 and D each represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ] More preferable examples of '//a include the following groups.

"Here, R, R, respectively represent -CHa, CHzCHa or -CH(CH3)2, and R2, respectively -R5-
CH7, -CH2CH3 or -CH(CH3). [Photopolymerization initiators useful for photocrosslinkable polymers may be those commonly used, but those suitable for the present invention include, for example, anthraquinone BB4 such as anthraquinone, 2-methylanthraquinone, and 2-ethylanthraquinone, and benzoin. , benzoin rust conductors such as benzoin methyl ether and benzoin ethyl ether, chlorthioxanthone,
Thioxanthone derivatives such as diisopropylthioxanthone, benzophenone, 4,4'-dichlorohensiphenone, Michler's ketone (4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone), dihenzohalone, Anthrone, benzophenone derivatives such as biancerani-methyl benzoyl benzoate, benzyl, benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal and other benzyl derivatives, p-dimethylaminoacetophenone,
pt-butyltrichloroacetophenone, 2. Hydroxy-2-methylpro and siphenon, acetophenone derivatives such as 2,2-jetoxyacetophenone, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propane Dione-2-(o-ethoxycarbonyl)oxime, 1
-Phenyl-1,2-propanedione-2-(o-benzoyl)oxime and other oximes are mentioned. Furthermore, sensitizers can also be used together with these initiators. Although there is no limit to the amount of these photopolymerization initiators used, it is preferably 0.1 to 30% by weight.

The base layer forming step of the present invention is a process of forming a wiring base layer selected from nickel, chromium, and chromium gold on the surface of the insulating layer for the purpose of improving the adhesion between the insulating layer and the wiring layer.

When a wiring layer is formed by electrolytic gold plating, a thin gold film is usually formed on an insulating layer by vapor deposition or electroless plating as a conductive layer, but because the adhesive strength between gold and polyimide is low, the conductive layer and wiring are The layers tend to peel off, resulting in a lack of reliability.

Therefore, various metals were investigated as adhesive base layers, and chromium, chromium gold, molybdenum, tungsten, titanium, aluminum, palladium, platinum, and nickel showed good results. Among these, chromium and nickel are the best, and can be easily patterned because they can be etched with acid or potassium ferricyanide aqueous solution. Furthermore, when it is necessary to increase the adhesion between the base layer and the gold wiring layer,
Preferably, chromium gold is used. The gold content of the chromium gold is preferably 1 to 99%, preferably 5 to 50%.

Cross uses evaporation method, sputtering method, ion coating method, C■D? method to form chromium gold layer. 1 to a thickness of 10 angstroms to 10 microns, preferably 100 angstroms to 1 micron, on one side on the insulating layer. Unnecessary portions are removed by etching after the wiring layer is formed. Etching is
Wet etching or dry etching can be selected. Examples of the wet etching solution include a mixture of an acid or ceric ammonium nitrate and perchloric acid, or a mixture of potassium ferricyanide and sodium hydroxide.

Examples of dry etching include ion milling and reactive ion etching, and examples of gases used include inert gas such as argon or chlorine gas (which may be diluted with air or an inert gas). It will be done.

In order to ensure adhesive strength between the underlayer and the insulating layer and good electrical continuity at the via hole portion, it is desirable to clean the surface of the insulating layer and the inside of the via hole before forming the underlayer.

There are two cleaning methods: a wet method and a dry method. Examples of cleaning solutions for the wet method include acids such as sulfuric acid, nitric acid, hydrofluoric acid, and acetic acid, aqueous sodium hydroxide, alkalis such as ammonia, ammonium hydroxide, hydrazine, and ethylenediamine, acetone, ethanol, trichlene,
Organic solvents such as freon, xylene, and catechol, ammonium persulfate aqueous solution, potassium ferricyanide aqueous solution,
Etchant for metals such as cerium ammonium nitrate aqueous solution can be mentioned.

Examples of the dry method include plasma ashing, plasma etching, spanner etching, and vapor phase etching. Examples of the gas used include argon, nitrogen, oxygen, carbon tetrachloride, carbon tetrafluoride, and chlorine.

The wiring layer forming process referred to in the present invention is to form a wiring pattern of gold that is difficult to oxidize on the surface of the underlying layer by plating, sputtering, vapor deposition, etc., and at the same time, make the via hole part conductive and connect it to the conductive pattern in the lower layer. This is the process of electrically connecting. More specifically, for example, in the case of a method of forming a wiring layer by plating, the surface of the underlying layer is roughened by liquid honing, plasma etching, etching with acid or alkali, etc., and the wettability and adhesion of the surface of the layer and inside the via hole are improved. improve. If necessary, a conductive layer of gold may then be formed by electroless plating or vapor deposition.

Next, parts other than the wiring pattern are masked using photoresist, and the gold wiring pattern and the inside of the via hole are plated by electroplating. Next, the photoresist is peeled off and quick etching is performed with sulfuric acid to remove unnecessary underlying layers other than the wiring areas. Instead of the electroless plating method in this method, there is also a method of forming a wiring pattern by sputtering or vapor deposition. A protective layer may also be formed on the wiring layer if necessary.

By repeating this insulating layer formation and wiring layer formation, a multilayer wiring board having multiple wiring layers can be manufactured.

〔Example〕

Next, the present invention and its effects will be explained using Examples, but the present invention is not limited thereto.

First, a method for producing a photocrosslinkable polymer forming an insulating layer used in the present invention will be explained using Reference Examples 1 to 4.

Reference Example 1 In a 500 m1 S' separable flask, 21.9 g of pyromellitic anhydride, 27.0 g of 2-hydroxyethyl methacrylate), and 100 m1 of r-butyrolactone.
was added, and 17.0 g of pyridine was added while stirring under water cooling.

After stirring at room temperature for 16 hours, a solution of 41.2 g of dicyclohexylcarbodiimide in 40 ml of γ-butyrolactone was added over 10 minutes while cooling with water, followed by 16.0 g of 4,4'-diaminodiphenyl ether over 15 minutes. After stirring for 3 hours under water cooling, 5 ml of ethanol was added and further stirred for 1 hour. After filtering the precipitate, the resulting solution was
In addition to ethanol in Step 1, the resulting precipitate was washed with ethanol and then vacuum dried to obtain a light brown powdered polymer (A-1).
) was obtained. Intrinsic viscosity [η] of the obtained A-1 polymer at 30° CIg/dl in N-methylpyrrolidone
was 0.22. The weight average molecular weight determined by GPC was 13,000.

A-1 Polymer 10g5 0.6g of Michler's ketone was dissolved in 14g of N-methylpyrrolidone to prepare polymer solution C.
-1 was obtained.

Reference Example 2 Synthesis was carried out in the same manner as in Reference Example 1 except that 32.2 g of benzophenone tetracarboxylic dianhydride was used instead of pyromellitic dianhydride.

10g of this powdered polymer, 0.6g of Michler's ketone
was dissolved in 14 g of N-methylpyrrolidone to obtain polymer solution C-2.

Reference Example 3 An amine solution was prepared by dissolving 110 g of diaminodiphenyl ether in 290 g of N-methylpyrrolidone.

177 g of hensifhenonetetracarboxylic dianhydride was dissolved in 310 g of dimethylacetamide, and then N-
180 g of methylpyrrolidone was added and dissolved to prepare an acid solution. 3j! 60℃ using a separable flask.
A polymer solution was obtained by adding an acid solution to the amine solution and reacting for 3 hours. 50 g of this polymer solution, a solution of 1.2 g of Michler's ketone dissolved in 30 g of N-methylpyrrolidone, and a solution of 9.6 g of dimethylaminoethyl meccrylate dissolved in 10 g of N-methylpyrrolidone were mixed, and polymer solution C-3 was prepared. I got it.

Reference Example 4 4°4°-diamino-3,3',5.5'-tetramethyldiphenylmethane in a cylindrical container equipped with a stirrer, a dropping funnel, an internal temperature needle, and a nitrogen inlet tube under a nitrogen gas atmosphere. Dissolve 70.1 g (0.28 mol) in 900 ml of N-methylpyrrolidone (NMP) and heat at 0 to 5°C.
Cool to Here, 90.2 g (0.28 mol) of benzophenone tetracarboxylic dianhydride (BTDA) was prepared and added in small amounts over 4 hours. The last addition 3
After 0 minutes, 62.3 g of triethylamine (0,63
mol) and 256.9 g (2.52 mol) of acetic anhydride are added dropwise, and the resulting polyamic acid is cyclized to polyimide. After stirring at room temperature for 16 hours, the f4 solution is poured into 201 water with vigorous stirring and the precipitated product is filtered. The product is treated with fresh 20 J of water, filtered and dried under vacuum at 80°C. 25 as a 0.5% solution of NMP
Intrinsic viscosity ηinh measured at °C is 0.79 dl/g
It is. The glass transition temperature (Tg) measured with a differential scanning calorimeter (DSC) is 309°C.

10 g of the obtained polymer was mixed with 20 g of N-methylpyrrolidone.
Polymer solution C-4 was obtained.

Example 1 A ceramic substrate of 50 mm square and 1 mm thick was degreased and cleaned. Next, after activating the surface using a dedicated centitizer and activator, a Ni layer was formed to a thickness of 500 cores using a Ni electroless plating solution (manufactured by Uezai Kogyo Co., Ltd.).

Thereafter, a photoresist (Microposi Nodo TF-20, Shipley Co., Ltd.) for mesochyrecyst was buttered to a thickness of 60 μm. Next, it was placed in an electrolytic gold metal 7ki bath (manufactured by Uezai Kogyo Co., Ltd.), and the current density was 50 mA/cn! Gold plated with 5 μm thickness, 50 μm in line, and 10 land diameter.
0 A! m, a gold pattern with a land spacing of 500 μm was obtained (conductive layer formation).

After removing the Menki resist with a special remover, a 500X Ni layer was formed in the same manner, and then a Ni protective layer was formed on the conductive layer using an etching photoresist (OMR-83 manufactured by Tokyo Ohka Co., Ltd.). Sulfuric acid was used as the Ni etching solution (forming a protective layer).

Polymer solution C-1 prepared in Reference Example 1 was applied to the substrate on which the conductive layer and the protective layer were formed using a spin coater for 700 min.
After forming a film by rotating at rpm for 10 seconds, it was dried for 120 minutes using a hot air dryer at 70°C. Then add 75μ to this
A photomask with mφ black circles arranged at 500 μm grid spacing was placed in close contact with the photomask, and exposure was performed for 2 minutes using a mask liner (exposure machine) equipped with a 250 W ultra-high pressure mercury lamp. After exposure at 70°C for 15 minutes, a developer solution of γ-butyrolactone/isopropyl alcohol (volume ratio of 1 layer: 1)
Second Pj: After crushing, rinse with isopropyl alcohol. Subsequently, under nitrogen atmosphere at 200°C for 1 hour, and then for an additional 40
It was heat-treated at 0° C. for 1 hour to be thermally cured. The thickness of the obtained insulating layer was 1011 m (insulating layer formation).

Next, the surface of the insulating layer and the inside of the via hole were cleaned and roughened with oxygen plasma (0.4 Torr, 100-110 minutes) using a dry etching device (OEM-451 manufactured by Nikkei Anelha Co., Ltd.), and then the Ni layer was formed to a thickness of 5,000 yen by electroless plating in the same manner as described above (base layer formation).

Next, a 5 μm thick gold wiring pattern was formed by electroplating in the same manner as the conductive pattern was formed.
It was electrically connected to the underlying conductive pattern via a via hole (wiring layer formation).

In the same manner, insulating layer formation and wiring layer formation were repeated to produce a multilayer wiring board consisting of seven conductor layers.

Using this multilayer wiring board having 1000 via holes, a via hole connection reliability test was conducted using a thermal shock tester (TSB-IL manufactured by Tabai Corporation). After 100 cycles of 150°C and -65°C, connection reliability was evaluated and no abnormalities such as disconnection were found.

Further, the increase in resistivity of the wiring layer was within 1%.

Example 2.3 A multilayer wiring board having an eight-layer conductor layer structure was manufactured in the same manner as in Example 1 using polymer solutions C-2 and C-4.

When the via hole connection reliability was evaluated in the same manner as in Example 1, no abnormality was found. Further, the increase in resistivity of the wiring layer was within 1%.

Example 4 After degreasing and cleaning a 50 mm square, 1 mm thick ceramic substrate, a sputtering device (5PF-43 manufactured by Nikkei Anelva) was used.
08), 5000 people of CrAu (Au content 1
0% by weight). After that, a photoresist (Microposit TF-20, Shipley Co., Ltd.) for metsukiresist was patterned to a thickness of 6 μm.Next, it was placed in an electrolytic gold plating bath (Kamizai Kogyo Co., Ltd.!!!1!) at a current density of 50 mA/ Gold plated with ant, thickness 5 μm, line width 50 μm, land diameter 100 μm, land spacing 50 μm.
A gold pattern of 0 μm was obtained (conductive layer formation).

CrAu of 2500 A is deposited on the obtained conductive layer substrate in the same manner as the sputtering method described above. A protective layer is formed on the conductive layer using an etching photoresist (Tokyo Ohka Co., Ltd. jlOMR-83). As the etching solution, a potassium ferricyanide aqueous solution was used (to form a protective layer).

Polymer solution C-1 prepared in Reference Example 4 was applied to the substrate on which the conductive layer and the protective layer were formed using a spin coater for 700 min.
After forming a film by rotating at rpm for 10 seconds, it was dried for 120 minutes using a hot air dryer at 70°C. Then, 75 μm
A photomask with black circles of φ at 500 μm grid spacing was placed in close contact with the photomask, and exposure was performed for 2 minutes using a mask aligner (exposure machine) equipped with a 250 W ultra-high pressure mercury lamp. After exposure 7
After processing at 0° C. for 15 minutes, it was immersed in a developer of T-butyrolactone/isopropyl alcohol (1 layer, 1 volume ratio) for 60 seconds, and then rinsed with isopropyl alcohol. Subsequently, heat treatment was performed at 200° C. for 1 hour and then at 400° C. for 1 hour in a nitrogen atmosphere for heat curing. The thickness of the obtained insulating layer is 10μ
m (insulating layer formation).

Next, the surface of the insulating layer and the inside of the via hole were cleaned and roughened with oxygen plasma (0.4 Torr, 100 W, 10 minutes) using a dry etching device (OEM-451 manufactured by Nikkei Anelha Co., Ltd.). Subsequently, a CrAu (Au content: 10% by weight) layer of 500K was formed in the same manner as the sputtering method described above (base layer formation).

Next, a 5 μm thick gold wiring pattern was formed by electroplating in the same manner as the conductive pattern was formed.
It was electrically connected to the underlying conductive pattern via a via hole (wiring layer formation).

In the same manner, insulating layer formation and wiring layer formation were repeated to produce a multilayer wiring board consisting of seven conductor layers.

Using this multilayer wiring board having 1000 via holes, a via hole connection reliability test was conducted using a thermal shock tester (TSB-IL manufactured by Tabai Corporation). 150℃ and 16
After 100 cycles at 5°C, connection reliability was evaluated and no abnormalities such as disconnection were found.

Further, the increase in resistivity of the wiring layer was within 1%.

Comparative Example 1 A conductive layer and a protective layer were formed in the same manner as in Example 1 except that C-3 was used as the polymer solution, and when an attempt was made to further form an insulating layer, it was only possible to form a film up to a thickness of 5 μm. .

Comparative Example 2 Degreasing a 50 mm square, 1 m square ceramic substrate.
After cleaning, sputtering equipment (5PF-
430H), 1oooi of Cr, and 2500λ
of Cu is deposited. Thereafter, a photoresist (Microposit TF-20, Shipley Co., Ltd.) for metsukiresist was patterned to a thickness of 6 μm. Subsequently, it was placed in a copper sulfate plating bath, and copper plating was performed at a current density of 5 A/cdr, with a thickness of 5 μm, 50 μm in one line, and a land of 110 μm.
A gold pattern with a land spacing of 500 μm was obtained (conductive layer formation).

After removing the Menki resist with a special remover, remove unnecessary C with an ammonium persulfate aqueous solution and a cerium nitrate aqueous solution.
Quick etching was performed on u and Crt:l.

On the obtained conductive layer, Cu of 1000 λ and Cr of 2500 type are deposited in the same manner as the sputtering method described above.

Photoresist for etching (OMR-8 manufactured by Tokyo Ohka Co., Ltd.
3) to form a protective layer on the conductive layer. As the etching solution, an ammonium persulfate aqueous solution and a cerium nitrate aqueous solution were used.

Polymer solution C-1 prepared in Reference Example 1 was applied to the substrate on which the conductive layer and the protective layer were formed using a spin coater for 700 min.
After forming a film by rotating at rpm for 10 seconds, it was dried for 120 minutes using a hot air dryer at 70°C. Then, 75 μm
A photomask with black circles of φ at 500 μm grid spacing was placed in close contact with the photomask, and exposure was performed for 2 minutes using a mask aligner (exposure machine) equipped with a 250 W ultra-high pressure mercury lamp. 70 after exposure
After processing at ℃ for 15 minutes, it was immersed in a developer of γ-butyrolactone/isopropyl alcohol (1 layer, 1 volume ratio) for 60 seconds, and then rinsed with isopropyl alcohol. Subsequently, heat treatment was performed at 200° C. for 1 hour and then at 400° C. for 1 hour in a nitrogen atmosphere for heat curing. The thickness of the obtained insulating layer was 10 μm (insulating layer formation).

Next, the surface of the insulating layer and the inside of the via hole were etched with oxygen plasma 7 (0.4 Torr, 100 W, 10 minutes) using a dry etching device (OEM-451 manufactured by Nikkei Anelva Co., Ltd.).
Cleaned and roughened the surface. Then Cr1OOO74
, Cu2500λ layers were formed in the same manner as above.

Next, a 5 μl thick copper wiring pattern was formed by electroplating in the same manner as the conductive pattern was formed.
Electrically connected to a conductive pattern via a via hole (wiring layer formation).

In the same manner, insulating layer formation and wiring layer formation were repeated to produce a multilayer wiring board consisting of seven conductor layers.

Using this multilayer wiring board having 1000 via holes, a via hole contact@reliability test was conducted using a thermal shock tester (TSB-IL manufactured by Tabai Corporation). 150℃ and 16
After 100 cycles at 5° C., connection reliability was evaluated and no abnormalities such as disconnection were found.

Next, when the resistivity of the wiring layer was measured, an increase of 5% was observed.

〔Effect of the invention〕

As explained above, according to the manufacturing method of the present invention, a base layer is provided on the insulating layer to improve adhesive strength with the wiring layer, and the wiring layer is formed of gold that is difficult to oxidize, so reliability is improved. It is possible to manufacture multilayer structure substrates with high efficiencies. Furthermore, the polymer used to form the insulating layer of the present invention has a feature that allows for easy formation of high-density via holes required for applications such as LSI mounting modules.

Claims (1)

[Claims] (1) (a) Step of forming a conductive pattern on the surface of the base substrate (conductive layer formation step); (b) General formula (I) ▲Mathematical formula, chemical formula, table, etc. are present on the conductive layer▼( I) [In the formula, X is a (2+n)-valent carbocyclic group or heterocyclic group, Y is a (2+m)-valent carbocyclic group or heterocyclic group, and Z is There are ▼, ▲mathematical formulas, chemical formulas,
There are tables, etc.▼, or▲There are mathematical formulas, chemical formulas, tables, etc.▼, R is a group having a carbon-carbon double bond, W is a group that can react with the carbonyl group of -COOR by heat treatment to form a ring, n is 1 or 2, m is 0
, 1 or 2, and COOR and Z are in the ortho or peri position] or general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (II) [However, in the formula, A is It represents a tetravalent carbocyclic group or a heterocyclic group, and B represents a divalent carbocyclic group or a heterocyclic group. ] A step of providing a photocrosslinkable polymer layer having a repeating unit represented by the formula, irradiating the layer with light through a photomask, forming a via hole by development, and subsequently heat-treating the layer to make it highly insulating. (insulating layer forming step), (c) forming a wiring layer base layer selected from nickel, chromium, and chromium gold on the surface of the insulating layer (base layer forming step), (d) further forming the base layer. A method for manufacturing a multilayer wiring board, comprising the steps of forming a gold conductor circuit on the surface of the board and electrically connecting it to a lower conductive pattern via a via hole (wiring layer formation step).