JPS60121740A - Multilayered wiring structure - Google Patents

Abstract

PURPOSE:To enable to obtain excellent moisture resistance by a method wherein an interlayer insulation layer is made of a photo or radiation-sensitive polyamide composite having high sensitivity and not changing in quality at the time of development. CONSTITUTION:A conductor metal is deposited on a substrate 7 with necessary built-in elements, and the lower conductor layer 8 of required pattern is formed. Next, it is coated with the solution of a photo-sensitive polyamide composite having high sensitivity and not changing in quality at the time of development, and a polyamide composite layer 9 is formed by evaporating the solvent. Then, it is exposed to light by the use of a photo mask and developed, resulting in the formation of through holes 10. The layer 9 is inverted into a polyimide resin layer 11. The upper conductor layer 12 is deposited over the whole substrate and formed by the photoetching technique into a required pattern electrically connected at the parts of the through holes 10 of the layers 8 and 11. Thereby, the multilayer wiring structure having excellent moisture resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a wiring structure for a semiconductor integrated circuit or a hybrid integrated circuit, and particularly to a multilayer wiring structure in which the wiring structure has two or more layers.

[Background of the Invention 1] Multilayer wiring structures using polyimide resin in semiconductor integrated circuits or hybrid integrated circuits have conventionally been manufactured by the method shown in FIG. That is, a lower conductor layer 2 having a predetermined pattern is formed on a substrate 1 on which necessary elements are formed by a well-known photoetching technique. Thereafter, a polyamic acid (polyimide precursor) face is applied and cured to form a polyimide resin layer 6 (FIG. 1 (α)). Next, a photoresist 4 is applied onto the polyimide resin layer 3 and dried (
Figure 1 (h)). The photoresist 4 is exposed using a predetermined photomask, developed, and dried to obtain a predetermined pattern (FIG. 1(C)).

A predetermined portion of the polyimide resin layer 6 is selectively removed by etching to form a through hole 5, and the lower conductor layer 2 in this portion is exposed (FIG. 1(d)).

Furthermore, by removing the photoresist 4 that is no longer needed, a pattern of the polyimide resin layer 5 is formed (see Fig. 1 (
t)). The upper conductor layer 6 is deposited on the entire surface of the substrate by means such as vacuum evaporation, and is formed into a predetermined pattern electrically connected to the lower conductor layer 2 through the through holes 50 of the polyimide resin layer 30 by photoetching. Figure 1 (f)
).

In this conventional technique, the polyimide resin layer must be patterned indirectly using a photoresist, and as mentioned above, there is a problem that the cost is high due to the large number of steps. In addition, various studies have been conducted to solve the above problems, for example, in Japanese Patent Application Laid-Open No. A heat-resistant photosensitive material designated as It-149754 was proposed. However, the sensitivity of this material is extremely low, on the order of several thousand meters, and the film cracks and peels when developed, making it impractical for manufacturing multilayer wiring structures. On the other hand, a polyamic acid composition with improved sensitivity has been filed as a photosensitive heat-resistant polymer composition (%Application No. 99421/1989). However, this composition had another problem in that the pattern in the exposed area was easily eluted during development, and particularly fine patterns were not formed, and it was insufficient for practical use.

[Purpose of the invention]

An object of the present invention is to solve the various problems of the prior art described above and to provide a multilayer wiring structure with high moisture resistance and reliability.

[Summary of the Invention] The above object is achieved by forming the glabellar insulating layer from a light- or radiation-sensitive polyamic acid composition that has high sensitivity and does not change in quality during development.

The above multilayer wiring structure according to the present invention includes a first step of forming a lower conductor layer having a predetermined pattern on at least a portion of the substrate, and a polyamide acid reacting with light or radiation on the lower conductor layer. A second step of applying a solution of composition [A) and drying at a temperature of room temperature or higher and 120° C. or lower, and exposing the polyamic acid composition using a predetermined mask and then developing it to penetrate at least at a predetermined location. a third step of forming a polyamic acid composition layer having pores; a fourth step of heating and curing the polyamic acid composition layer at a temperature of 150° C. or higher and 500° C. or lower to convert it into a polyimide resin layer; a fifth step of forming an upper conductor layer in a predetermined pattern that is electrically connected to the lower conductor layer at the through-hole portion of the polyimide resin layer and extends at least partially on the polyimide resin layer; A multilayer wiring structure is manufactured by repeating the steps from the second step to the fifth step as necessary to form a plurality of wiring conductor layers.

(However, in the formula, 1 is a hexavalent or tetravalent organic group, R2 is a
A valent organic group, M represents hydrogen or ammonium ion, and L represents 2tl-. ) and (2) a bisazide represented by the general formula N, -几' Ns (rin) (wherein 几5 represents a divalent or trivalent organic group). A compound, (3) an amine compound (1) having a group having hydrogen bonded to a tertiary carbon, a group having hydrogen bonded to a secondary carbon, or an unsaturated bond in the molecule, and (4) optionally A polyamic acid composition comprising an added sensitizer.

The above bisazide compound [■] is 01 parts by weight or more and 1 ooit part or less based on the poly7]00 heavy background part having the repeating unit shown in [1] above, and the amine compound [1] is ] is preferably blended in a proportion of 1 part by weight or more and 400 parts by weight or less with respect to 100 parts by weight of the polymer having the repeating unit shown.

A method of manufacturing a multilayer wiring structure according to the present invention will be described with reference to FIG.

A conductive metal is deposited by a vacuum evaporation method or the like on the substrate Z on which necessary elements are formed, and a lower conductor layer 8 having a predetermined pattern is formed by a well-known 71) etching technique. Next, a solution of the polyamic acid composition (A) is applied, and the solvent is evaporated at a temperature above room temperature and below 100° C. to form a polyamic acid composition layer 9 (FIG. 2 (α)). Next, the through holes 10 are exposed using a predetermined mask and then developed.
form. After that, the polyamic acid composition layer 9 was coated with 15
It is converted into a polyimide resin layer 11 at a temperature in the range of 0° C. or higher and 500° C. or lower (FIG. 2(b)). Upper conductor layer 12id
It is deposited on the entire surface of the substrate by means such as vacuum evaporation, and is formed into a predetermined pattern electrically connected to the lower conductor layer 8 and the polyimide resin layer 110 at the through holes 10 by photoetching (see FIG. 2). (C)).

The composition (A) is made by reacting the carboxyl group of the polyamic acid (1) with the amine group of the amine compound (1) through ionic bonding, and blending this with a bisazide compound (Ell). The resulting bisnitrene reacts with unsaturated bonds and the like to crosslink the cibolimer and make it insolubilized in the solvent. Therefore (A) gives a negative type image.

The substrate used in the present invention is a silicon wafer, glass, ceramic, etc., and depending on the purpose, the substrate may be 5ty2°Ta205.
Any metal oxide film such as Inn20s can be provided.

The lower conductor layer and the upper conductor layer are deposited by vacuum evaporation, sputtering, or the like. Al is mainly used as the conductor metal, but Cu, Au+Pt, Cr
, i'i, Mo, W, 'ra, Mn
It is an alloy of two or more of these metals and metals.

You can.

The polyamic acid used in the present invention may consist only of the repeating unit (1), or may be a copolymer with other repeating units.

1.1] In the formula, B, +: R, 2 is preferably an aromatic organic group or a heterocyclic organic group from the viewpoint of heat resistance when used as a polyimide, but is not limited thereto. As R1, C
H.

In the formula Σ@C, the bond represents a bond with the carbonyl group of the polymer main chain, and the carboxyl group is located at the ortho position to the bond. ) are preferred, but are not limited to these. Examples of R2 include the following.

The polyamic acid represented by the repeating structural unit (1) is usually used in a state dissolved in an aprotic polar solvent. As an aprotic polar solvent, N-methyl-2
-pyrrolidone, N.

N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-acetyl-ε-caprochrome, 1,3-dimethyl-2-imidazolidinone, and the like are preferably used. Furthermore, two or more of the above solvents may be used in combination.

Examples of the bisazide compound (1) used in the present invention include 4.4'-diazidodiphenylmethane, 4.4'-diazidodiphenyl, 4.4'-diazidoacetophenone, 4.4'-diazidostilbene, 4゜4'-Diazidochalcone, 4. /I'-Diazidobenzalacetone, 2
, 6-di(4'-azidobenzal)-cyclohexanone, 2,6-di(4'-azidobenzal)-4-methylcyclohexanone, 2,6-di(4'-azidobenzal)
-4-hydroxycyclohexanone, 2,6-di(4'
-azidobenzal)-,4-hydroxymethylcyclohexanone, 4,4'-diazido-6,6'-dicarboxystilbene, 2-di(4-azidocinnamoyloxy)ethane, 2,6-di(4'-azido) Cinnamiriden)
-4-hydroxymethylcyclohexanone, 6-azido-2-(4'-azidostyryl)benzimidazole,
Examples include, but are not limited to, 6-azido-2-(4'-azidostyryl)benzthiazole and 5-azido-2'-(,1'-azidostyryl)benzoxazole. The blending ratio of bisazide compound (n) is (1
) is desirably used in an amount of 01 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of the polymer having the repeating unit. More preferably, it is used in an amount of 05 parts by weight or more and 50 parts by weight or less. Outside this range, developability,
This will have a negative impact on the storage stability of the festival.

Examples of amine compounds used in the present invention include allylamine, diallylamine, triallylamine, 2-methyl-2-butenylamine, 1,'5-dimethyl-1-
Propenylamine, 2,4-pentagenylamine, tri(2-butenyl)amine, di(2-methyl-2-propenyl)amine, 2-(N,N-dimethylamino)ethylcinnamate, s -(N, N-dimethylamino)propyl acrylate, 5-(N,N-dimethylamino)
propyl metharylate, 3-(N,N-dimethylamino)propylsinname), N,N-dimethylamine,
N-methyl-diallylamine, N-propyldiallyl
Amino, 2-vinylpyridine, 2-vinyl-6-methylpyridine, 2-vinyl-5-ethylpyridine, 4-butenylpyridine 1,1l-(1-propenylbutenyl)pyridine, 4-pentenylpyridine, 4-(1 -7" tenylpentenyl) pyridine, 2-(4-pyridyl) allyl alcohol, etc. The blending ratio of the amine compound [I] is (I) a polymer having 1 repeating unit 10
It is desirable to use 1 part by weight or more and 400 parts by weight or less, more preferably 10 parts by weight or more and 40 parts by weight relative to 0 parts by weight.
It is desirable to use it in an amount of 0 parts by weight or less. Deviation from the above range will have an adverse effect on the developability or the quality of the polyimide film of the final product.

A sensitizer may be appropriately added to the polyamic acid composition that reacts with light or radiation for the purpose of further improving sensitivity. The amount added is [1].

(If), 01 of the total weight of the compound represented by (1)
- It is preferable to use it in a range of 10% or less. Outside this range, the developability and the quality of the polyimide film of the final product will be adversely affected. Sensitizers for bisazide compounds include anthrone, 1,9-benzaantrone, acridine, cyanoacridine, nitropyrene, 1,8-dinitropyrene,
Mihiraketone, 5-nitroacenaphthene, 2-nitrofluorene, pyrene-1,6-quinone, 9-fluorenone, 1,2-benzanthraquinone, 2-chloro-1,2
-benzanthraquinone, 2-bromobenzanthraquinone, 2-chloro-1,8-phthaloylnaphthalene, and the like are preferably used.

The polyamic acid composition used in the present invention can be patterned using ordinary photolithography techniques. Application to the substrate can be appropriately selected from methods such as spin coating, dipping, spraying, and printing. Good adhesion is often obtained by performing a well-known coupling treatment using an adhesion aid as a pre-treatment for coating. As an adhesion aid, organosilicon compounds such as γ-aminepropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-meccryloxypropyltrimethoxysilane, or aluminum monoethylacetoacetate diisopropylene are used as adhesion aids. rate,
Aluminum chelate compounds such as aluminum tris (ethyl rare heptoacetate) and aluminum tris (malonic acid ethyl ester) fx are used.

Drying is performed at a temperature selected from the range of room temperature or higher and 100° C. or lower. If the temperature is lower than room temperature, it will take a long time for the solvent to evaporate, making it impractical. If the temperature is higher than 100°C, thermal decomposition of the bisazide compound occurs and it no longer functions as a photosensitive group. Also, good results are often obtained by drying under reduced pressure.

Ultraviolet light is usually used for exposure, but visible light, deep ultraviolet light, electron beams, X-rays, and ion beams may also be used.

As a developer, N-methyl-2-pyrrolidone, N,N-
Dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexameflL, phosphoric triamide, N-acetyl-ε-caglolactam, 1
．． Aprotic polar solvents such as 3-dimethyl-2-imidazolidinone alone or methanol, ethanol,
It can be used as a mixed solution of polyamic acid with a non-solvent such as isopropyl alcohol, benzene, toluene, xylene, and methyl cellosolve.

The pattern formed by development is washed with a rinse solution to remove the developing solvent gold. For the rinsing solution, a polyamic acid non-solvent having good miscibility with the developer is used, and preferred examples include methanol, ethanol, isopropyl alcohol, benzene, toluene, xylene, and methyl cellosolve.

The polyamic acid composition obtained by the above treatment is heat-treated to form a pattern of a heat-resistant polymer having imide rings and other cyclic groups. The heating temperature is selected from the range of 150°C or higher and 500°C or lower. If the temperature is lower than 150°C, the ring-closing reaction may not occur or may be extremely slow, making it impractical.

If the temperature is higher than 500°C, thermal decomposition of the polymer will occur, which is not preferable. When the heat treatment temperature exceeds 300°C, it is desirable to use an inert gas atmosphere such as N2.

Prior treatment of the polyimide in a plasma discharge atmosphere before depositing the top conductor gold P4 improves the adhesion between the polymer and the top conductor. Oxygen plasma is commonly used for this purpose. Further, in order to make the electrical connection between the lower conductor and the upper conductor more reliable at the through-hole portion, surface treatment can be performed. This is a process for removing a thin oxide film formed on the surface of the lower conductor, and is accomplished by using an etching solution for the lower conductor metal or an oxide etching solution.

[Embodiments of the invention]

The present invention will be explained below with reference to Examples. In advance, Table 1 11. A solution of a polyamic acid composition shown in /162 was obtained.

4,4'-diaminodiphenyl ether 1 under nitrogen stream
ao,q (0.5 mol) was dissolved in N-methyl-2-pyrrolidone 1791y. Next, pyromellitic dianhydride 109y (0.5 mol) was added to this solution while stirring while maintaining the temperature at about 15° C. by water cooling. After the addition, the reaction was further carried out at about 15°C for 3 hours to add 2-(
N,N-dimethylamino)ethyl methacrylate 1.5
Dissolve 7g, 2.6-di(4'-azidobenzal)-4-methylcyclohexanone, 0.37.9g, then 5μ
The mixture was filtered under pressure using an m-pore filter to obtain a solution of waste 1 in Table 1 of the polyamic acid composition.

Similarly, under a nitrogen stream, diaminodiphenyl ether/
L/90 g (0.45 mol), 4,4'-diaminodiphenyl ether-3-alponamide 1t41(O
, OS mol) with N-methyl-2-pyrrolidone and N,N-
1764g of mixed solvent with the same volume ratio of dimethylacetamide
54.5F of pyromellitic dianhydride under stirring while maintaining this solution at a temperature of about 15°C by cooling with water.
(0,25 mol), 3,3',4,4'-benzophenonato dicarboxylic dianhydride eo, sg (0,
25 mol) was added. After the addition is complete, the temperature is further increased to about 15°C.
2-(N,N-dimethylamino) was added to the polyamic acid solution (C) 20y with a viscosity of 55 Boise (30°G) for 3 hours.
ethyl methacrylate) 1.57y, 2,6-di(4'-
azidobenzal)-4-methylcyclohexanone 074
g was dissolved and then filtered under pressure using a filter with 5 μm pores to obtain a solution of polyamic acid composition 762 in Table 1.

Thereafter, solutions of polyamic acid compositions shown in Table 1/163 to Scrap 9 were obtained in the same manner.

Example 1 FIG. 3 shows a sectional view of a thermal recording head manufactured according to the present invention. A Tα205 layer 14 of approximately i ooo
Si layer 15, about 1000 07 layers 16, about 2 pm A
Four layers 17 were deposited, and a resist pattern was obtained using a negative type resist with an OMf of -83 (Tokyo Ohka Co., Ltd.). Next, A6 layer 1 was removed using an etching solution consisting of phosphoric acid, nitric acid, acetic acid, and water.
7. Cr layer with ceric ammonium nitrate aqueous solution,
16, and the Cr-Si layer 15 with a mixed acid of fluoric acid and nitric acid)
i-th selection etching was performed.

L, j-; After 6, the resist is removed using S-502 (Tokyo Ohkasho) to form a first wiring conductor layer with a wiring width of 90 μm and a wiring interval of 35 μm. Next, use another mask to etch A, L, and Cr in the same manner as above, so that each side is 90 μm.
A rectangular Cr-8i resistor pattern with the other side of 250 μm was obtained. Sequentially 2μm on the resistor by mask sputtering
A resistor protection layer 18 is formed by providing 5tO2 and 3μm of Ta205.

In order to increase the adhesive strength between the polyimide layer and the base, a 1% solution of aluminum monoethyl acetoacetate diisopropylate was applied and heat treated at 350° C. in an oxygen atmosphere to obtain an oxide film of A7.

Nineteen polyimide layers were formed as follows.

The composition solution of Table 1/r61 was spin-coated and
After drying for 0 minutes, a coating film with a thickness of 4 μm was formed and exposed to ultraviolet light using a predetermined emulsion mask. Next, it was developed with a mixture of 4 volumes of N-methyl-2-pyrrolidone and 1 volume of ethanol.
Rinse with ethanol and create a circular through hole 2 with a diameter of 50 μm.
I got o. The sensitivity was 116 m)'/cm2, and the pattern edges were clear. Next, in a nitrogen atmosphere,
A polyimide layer 19 having a thickness of about 2 μm was formed by heat treatment at 50° C. for 50 minutes.

The pattern edges were the same as before heat treatment. Then again,
Repeat coating, drying, exposure, development, and heat treatment for a total of approximately 4 times.
A μm layer polyimide layer 19 was obtained.

The second layer wiring conductor was formed as follows. The above substrate on which the polyimide layer was formed was treated with oxygen plasma to give a
Cr 21 with a thickness of λ and Cu 22 with a thickness of about 1.2 μm are deposited by one-shot sputtering to form a photoresist image. After that, about 6 itm of Cu, 22 was applied by electroplating.
, 2ttm of PA and 3ttm of Sn are formed.

Next, the resist was removed, and CIL1Cγ was selectively removed by sequential etching. The plated Pb and Sn are melted by heat treatment at 380° C. and become solder 23, completing the second layer wiring.

The obtained multilayer wiring structure was heated at 120°C and 2 atm.

When left in an atmosphere of 854RH and subjected to a moisture resistance test,
50% corrosion occurred after 25 hours.

Examples 2 to 9 Multilayer wiring structures for thermal recording heads were manufactured in the same manner as in Example 1 using polyamic acid compositions of /162 to A9 in Table 1. In all Examples, the sensitivity and pattern accuracy of the polyamic acid were excellent, and the two-layer wiring structure of the thermal recording head could be easily manufactured.

The obtained multilayer wiring structure was subjected to a moisture resistance test in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Example 10 FIG. 4 shows a cross-sectional view of a semiconductor integrated circuit manufactured according to the present invention. Emitter 2 built into silicon wafer 24
5. In order to take out the electrodes from each region of the collector 26 and base 27, an opening is provided at 5t0228. The first layer wiring conductor is formed by depositing A129 with a thickness of about 2 μm by vacuum evaporation, and obtaining a predetermined pattern by photoetching. In order to increase the adhesive strength between the polyimide layer and the base, a thin film of aluminum monoethyl acetoacetate diisopropylate is formed and heat treated in oxygen at 350°C. Thirty polyimide layers were patterned using the polyamic acid composition shown in Table 1 A6A in the same manner as in Example 1 to obtain through holes 51, which were formed by heat treatment at 400° C. in a nitrogen atmosphere. The sensitivity of polyamic acid was 100 m/cnL2, and the pattern accuracy was good. Note that the film thickness of polyimide/1i30 is about 4 μm, and the through hole 29 is a square with one side of 10 μm. In order to increase the adhesive strength between the polyimide layer and the second layer wiring conductor, the polyimide layer is treated with oxygen plasma. Next, an Al hole 2 of about 3 μm is deposited by vacuum evaporation and patterned by photoetching to form a second layer wiring conductor.

The obtained multilayer wiring structure was subjected to a moisture resistance test in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Examples 11-14 A2. of Table 1 was carried out in the same manner as in Example 10. A6, A6B,
A semiconductor integrated circuit was manufactured using the polyamic acid composition of No. 469. In either case, the sensitivity and pattern accuracy of the polyamic acid composition were excellent, and a two-layer wiring structure could be easily manufactured.

The obtained multilayer wiring structure was subjected to a moisture resistance test in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Comparative Example 1 The experimental results obtained from the above-mentioned JP-A-54-145794ζ are shown as a comparative example.

2-(N,N
-dimethylamino)ethyl methacrylate (1.57y) was dissolved and filtered under pressure using a filter with 5 μm pores. Using this composition (film thickness: 4 μm), an attempt was made to manufacture a two-layer wiring structure for a thermal recording head in the same manner as in Example 1, but the sensitivity was 320 am)'/am' in Table 1. I6
It was lower than any of the polyamic acid compositions No. 9, and the pattern obtained by development had cracks from the ends of the openings of the through holes, making it impossible to manufacture a multilayer wiring structure.

Comparative Example 2 A two-layer wiring structure for a thermal recording head was manufactured using thermosetting polyamic acid. This multilayer wiring structure was subjected to the same moisture resistance test as in Example 1.

As a result, the aluminum wiring corroded 50% in 15 hours.

As described in detail above, the multilayer wiring structure of the present invention was superior in moisture resistance to conventional products.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a method for manufacturing a multilayer wiring structure according to the prior art, FIG. 2 is a diagram showing a method for manufacturing a multilayer wiring structure according to the present invention, and FIG. 3 is an example of a multilayer wiring structure according to the present invention. FIG. 4 is a sectional view showing Examples 10 to 14 of the multilayer wiring structure according to the present invention. 7: Substrate 8: Lower conductor layer 9: Boriamic acid composition layer 10: Through hole 11: Polyimide resin layer 12: Upper conductor layer Fig. 1

Claims (1)

[Claims] A multilayer wiring structure characterized in that the glabella insulating layer is made of a cured product of a light- or radiation-sensitive polyamic acid composition having high sensitivity and good developer resistance.