JPS6331939B2 - - Google Patents

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] 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) varnish is applied and cured to form a polyimide resin layer 3 (FIG. 1a). Next, a photoresist 4 is applied onto the polyimide resin layer 3 and dried (FIG. 1b). The photoresist 4 is exposed using a predetermined photomask, developed, and dried to obtain a predetermined pattern (FIG. 1c). Predetermined portions of the polyimide resin layer 3 are selectively removed by etching.
A through hole 5 is formed to expose this portion of the lower conductor layer 2 (FIG. 1d). Further, by removing unnecessary photoresist 4, a pattern of polyimide resin layer 3 is formed (FIG. 1e). The upper conductor layer 6 is deposited on the entire surface of the substrate by means such as vacuum evaporation, and the lower conductor layer 2 is deposited by a photo-etching technique.
and are formed in a predetermined pattern electrically connected at the through holes 5 of the polyimide resin layer 3 (first
Figure 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 made to solve the above problems, and for example, a heat-resistant photosensitive material has been proposed as disclosed in Japanese Patent Application Laid-Open No. 149754/1983. However, this material has a low sensitivity of several thousand mj/cm ³ and the film easily cracks 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 (Japanese Patent Application No. 1983-99421). However, this composition has another problem in that the pattern in the exposed area is easily eluted during development, and particularly fine patterns are not formed.
It was insufficient for practical use. [Object 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 interlayer 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 includes a first step of forming a lower conductor layer having a predetermined pattern on at least a portion of the substrate, and a polyamic acid composition that reacts with light or radiation on the lower conductor layer. A]
a second step of applying a solution of and drying at a temperature above room temperature and below 120°C, and exposing the polyamic acid composition using a predetermined mask and then developing it to form a polyamic acid composition having through holes at least at predetermined locations. A third step of forming a composition layer, 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, and forming a through-hole in the polyimide resin layer. a fifth step of forming an upper conductor layer having a predetermined pattern that is electrically connected to the lower conductor layer at a portion thereof and extending at least a portion of the upper conductor layer on the polyimide resin layer; A multilayer wiring structure is manufactured by repeating the steps from step to fifth step to form a plurality of wiring conductor layers. [A](1) General formula (However, in the formula, R ¹ is a trivalent or tetravalent organic group,
R ² represents a divalent organic group, M represents hydrogen or ammonium ion, and n represents 1 or 2. )
A polymer having a repeating unit represented by (2) a bisazide compound represented by the general formula N ₃ −R ³ −N ₃ [] (wherein R ³ represents a divalent or trivalent organic group) and (3) an amine compound 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) an additive added as necessary. A polyamic acid composition comprising a sensitizing agent. In addition, the above bisazide compound [] is a polymer 100 having the repeating unit shown in the above [].
0.1 parts by weight or more and 100 parts by weight or less based on parts by weight, and the amine compound [ ] is 1 part by weight per 100 parts by weight of the polymer having the repeating unit shown in [ ] above.
It is preferable that the amount is blended in a proportion of not less than 400 parts by weight. 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 vacuum evaporation or the like on the substrate 7 on which the necessary elements are formed, and a lower conductive layer 8 having a predetermined pattern is formed by a well-known photo-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. 2a). Next, exposure is performed using a predetermined photomask, followed by development to form the through hole 10. After that, the polyamic acid composition layer 9 was heated to 150°C.
It is converted into a polyimide resin layer 11 at a temperature in the range from above to 500° C. (FIG. 2b). The upper conductor layer 12 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 at the through-holes 10 of the polyimide resin layer 11 by photo-etching. formed (Fig. 2c). The composition [A] is a product in which the carboxyl group of polyamic acid [] and the amino group of an amine compound [] are reacted through ionic bonding, and a bisazide compound [] is blended with this, and the bisazide is separated from the bisazide when irradiated with light or radiation. The produced bisnitrene reacts with unsaturated bonds and the like to crosslink the polymer and make it insolubilized in the solvent. Therefore, [A] gives a negative type image. The substrate used in the present invention is silicon wafer, glass, ceramic, etc., and depending on the purpose, SiO ₂ ,
A metal oxide film such as Ta ₂ O ₅ or In ₂ O ₃ 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,
It may be a metal such as Cr, Ti, Mo, W, Ta, Mn, or an alloy film or multiple film of two or more of these metals. The polyamic acid used in the present invention may consist only of repeating units [ ] or may be a copolymer with other repeating units. []
In the formula, R ¹ and R ² are preferably aromatic organic groups or heterocyclic organic groups from the viewpoint of heat resistance when used as polyimide, but are not limited thereto. As R ¹

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[Formula] (In the formula, 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.), but is not limited thereto. As an example of R ² ,

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[Embodiments of the invention]

The present invention will be explained below with reference to Examples. Solutions of polyamic acid compositions shown in Table 1 No. 1 and No. 2 were obtained in advance in the following manner. 100 g (0.5 mol) of 4,4'-diaminodiphenyl ether was dissolved in 1791 g of N-methyl-2-pyrrolidone under a nitrogen stream. Next, 109 g (0.5 mol) of pyromellitic dianhydride was added to the solution while stirring and maintaining the temperature at about 15° C. by cooling with ice. After the addition was completed, the reaction was continued for 3 hours at about 15°C to form a polyamic acid solution with a viscosity of 60 poise (30°C) [B].
I got it. 1.57 g of 2-(N,N-dimethylamino)ethyl methacrylate and 0.37 g of 2,6-di(4'-azidobenzal)-4-methylcyclohexanone were dissolved in 20 g of solution [B], and then filtered using a 5 μm pore filter. The polyamic acid composition No. 1 in Table 1 was filtered under pressure.
A solution of 1 was obtained. Similarly, under a nitrogen stream, 90 g (0.45 mol) of diaminodiphenyl ether, 11.4 g of 4,4'-diaminodiphenyl ether-3-albonamide
(0.05 mol) with N-methyl-2-pyrrolidone and N,
Mixed solvent of N-dimethylacetamide in the same volume ratio
1764g, and cooled this solution to about 15℃ by ice-cooling.
While stirring at a temperature of
(0.25 mol) was added. After the addition is complete, let the reaction continue for 3 hours at approximately 15°C until the viscosity is 55 poise (30°C).
foliamic acid

[Formula] (However, R ⁴ is

[Formula] and

[Formula] is 1:1, R ⁵ is

[Formula] and

A solution [C] having the formula [formula] of 9:1) was obtained. 1.57 g of 2-(N,N-dimethylamino)ethyl methacrylate and 0.74 g of 2,6-di(4'-azidobenzal)-4-methylcyclohexanone were dissolved in 20 g of solution [C], and then filtered using a 5 μm pore filter. Polyamic acid composition No. 2 in Table 1
A solution of was obtained. Thereafter, solutions of polyamic acid compositions shown in Table 1 Nos. 3 to 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. Approximately 1000 Å thick Ta ₂ O ₅ layer 1 is placed on the glazed alumina substrate 13 as an etching barrier.
4, and sequentially deposit approximately 1000Å by sputtering.
Cr-Si layer 15, about 1000 Å Cr layer 16, about 2 μm thick
An Al layer 17 was deposited, and a resist pattern was obtained using OMR-83 (negative resist manufactured by Tokyo Ohka Co., Ltd.).
Next, the Al layer 17 was coated with an etching solution consisting of phosphoric acid, sulfuric acid, acetic acid, and water, the Cr layer 16 was coated with aqueous ceric ammonium nitrate solution, and the Cr layer 16 was coated with a mixed acid of fluoric acid and nitric acid.
The Cr--Si layer 15 was selectively etched in sequence. After that, remove the resist with S-502 (manufactured by Tokyo Ohka),
A first wiring conductor layer having a wiring width of 90 μm and a wiring interval of 35 μm is formed. Next, using another mask, Al and Cr were etched in the same manner as above to obtain a rectangular Cr--Si resistor pattern with one side of 90 .mu.m and the other side of 250 .mu.m. A 2 μm layer is sequentially applied to the resistor using mask sputtering.
Resistor protection layer 18 with SiO ₂ and 3 μm Ta ₂ O ₅
shall be. To increase the adhesive strength between the polyimide layer and the base layer 1
% aluminum monoethyl acetoacetate diisopropylate in an oxygen atmosphere.
An oxide film of Al was obtained by heat treatment at 350°C. Polyimide layer 19 was formed as follows. The composition solution of Table 1 No. 1 was applied by spin coating at 80°C.
A coating film of 4 μm thickness was dried for 30 minutes and exposed to ultraviolet light using a prescribed emulsion mask. Then N-
It was developed with a mixture of 4 volumes of methyl-2-pyrrolidone and 1 volume of ethanol, and rinsed with ethanol to obtain circular through holes 20 with a diameter of 50 μm. Furthermore, the sensitivity is
It is 118mj/ ^cm2 and the pattern edges are clear.

【table】

[Table] Atsuta. Next, heat treatment was performed at 350° C. for 30 minutes in a nitrogen atmosphere to form a polyimide layer 19 with a thickness of about 2 μm.
The pattern edges were the same as before heat treatment. Next, coating, drying, exposure, development, and heat treatment were repeated again to obtain a polyimide layer 19 having a total thickness of approximately 4 μm. The second layer wiring conductor was formed as follows. The substrate on which the polyimide layer is formed is treated with oxygen plasma, and Cr21 of about 500 Å and Cu22 of about 1.2 μm are sequentially deposited by sputtering to form a photoresist image. After that, Cu22 is removed by electroplating.
6 μm thick, 2 μm thick Pb layer, and 3 μm thick Sn layer. Next, the resist was removed, and Cu and Cr were selectively removed by 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 to 120℃, 2 atmospheres, and 85℃.
When a moisture resistance test was performed by leaving it in an atmosphere of %RH, the Al wiring corroded 50% 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 the polyamic acid compositions No. 2 to No. 9 in Table 1. In all Examples, the sensitivity and pattern accuracy of polyamic acid were excellent, and the two-layer wiring structure of the thermal recording head could be easily manufactured. A moisture resistance test of the obtained multilayer wiring structure was carried out in Example 1.
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. Openings are provided in the SiO ₂ 28 in order to take out the emitter 25, collector 26, and base 27 formed in the silicon wafer 24. The first layer wiring conductor is formed by depositing Al29 with a thickness of about 2 .mu.m by vacuum evaporation, and a predetermined pattern is obtained 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 at 350°C in oxygen. The polyimide layer 30 was formed by patterning the polyamic acid composition of Table 1 No. 1 in the same manner as in Example 1 to obtain through holes 31, and heat-treating the layer at 400° C. in a nitrogen atmosphere.
The sensitivity of polyamic acid was 100 mj/cm ² and the pattern accuracy was good. Note that the polyimide layer 30
The film thickness is approximately 4 μm, and each side of the through hole 29 is 10 μm.
It is a square of m. In order to increase the adhesive strength between the polyimide layer and the second layer wiring structure, the polyimide layer is treated with oxygen plasma. Next, approximately 3μm Al32
is deposited by vacuum evaporation and patterned by photo-etching to form a second layer wiring conductor. A moisture resistance test of the obtained multilayer wiring structure was carried out in Example 1.
The same results as in Example 1 were obtained. Examples 11 to 14 In the same manner as Example 10, No. 2, No. 6, and No. 1 in Table 1 were prepared.
A semiconductor integrated circuit was manufactured using the polyamic acid composition No. 8 and No. 9. In either case, the sensitivity and pattern accuracy of the polyamic acid composition are excellent;
A two-layer wiring structure could be easily manufactured. A moisture resistance test of the obtained multilayer wiring structure was carried out in Example 1.
The same results as in Example 1 were obtained. Comparative Example 1 The experimental results according to the above-mentioned Japanese Patent Application Laid-Open No. 145794/1986 are shown as a comparative example. 2-(N,
N-dimethylamino)ethyl methacrylate 1.57
g was dissolved and filtered under pressure using a 5 μm pore filter. 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 3200 mj/cm ² , as shown in Table 1.
It was lower than any of the polyamic acid compositions No. 1 to 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 heat-sensitive 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 detailed above, the multilayer wiring structure of the present invention has
Moisture resistance was superior to conventional products.

[Brief explanation of the drawing]

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. 1 to 9, and FIG. 4 is a cross-sectional view showing Examples 10 to 9 of the multilayer wiring structure according to the present invention.
14. FIG. 7: Substrate, 8: Lower conductor layer, 9: Polyamic acid composition layer, 10: Through hole, 11: Polyimide resin layer, 12: Upper conductor layer.

Claims (1)

[Scope of Claims] 1. A multilayer wiring structure characterized in that the interlayer insulating layer is made of a cured product of a light- or radiation-sensitive polyamic acid composition shown in [A] below. [A](1) General formula (However, in the formula, R ¹ is a trivalent or tetravalent organic group,
R ² represents a divalent organic group, M represents hydrogen or ammonium ion, and n represents 1 or 2. )
A polymer having a repeating unit represented by (2) a bisazide compound represented by the general formula N ₃ −R ³ −N ₃ [] (wherein R ³ represents a divalent or trivalent organic group) (3) an amine compound 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) an additive added as necessary. A polyamic acid composition comprising a sensitizing agent.