JPH0555386A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent short circuit from occurring between wirings by a method wherein a second metal wiring is formed into a laminated structure where refractory metal is used as its upper layer, and the side wall of the second metal wiring is covered with an inorganic film. CONSTITUTION:A first metal wiring 5 is formed on an insulating film 2 provided onto a semiconductor substrate 1, the first metal wiring 5 is covered with a polyimide resin film 7, and a through-hole 7 is bored in the polyimide resin film 7 so as to enable the first metal wiring layer 5 to be exposed. Then, a second metal wiring 8 of laminated structure provided with a refractory metal layer 9 as an upper layer is formed on the polyimide resin film 7, and an inorganic film 10 is formed on all the surface including the second metal wiring 8. In succession, the inorganic film 10 is removed through anisotropical etching so as to be partially left covering the side wall of the second metal wiring 8. The polyimide resin film 7 is prebaked, and then an inorganic film 11 is formed all the surface. By this setup, short circuits are prevented from occurring between the wirings 5 ands 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a multi-layer wiring structure in which fine wiring is formed in multiple layers.

[0002]

2. Description of the Related Art Conventionally, a polyimide resin film, which is advantageous in flatness, has been used as an interlayer insulating film in this type of semiconductor device. The manufacturing method will be described with reference to FIG. First, as shown in FIG. 2A, after forming the aluminum wiring 22 on the insulating film of the semiconductor substrate 21, a silicon nitride film 23 is formed on the entire surface as shown in FIG. 2B, and then FIG. As described above, the polyimide resin film 24 is spin-coated and heat-treated.

Next, as shown in FIG. 3D, a through hole 24a is formed in the polyimide resin film 24 on the aluminum wiring 22 by using the photolithography technique and the dry etching technique. As shown in (e), the second metal wiring including the aluminum wiring 5 and the refractory metal film 26 is formed by a known technique. Then, as shown in FIG. 3F, after prebaking is performed in the P-CVD apparatus to remove water from the polyimide resin film 24, the silicon nitride film 27 of the cover is formed by the P-CVD method. The multilayer wiring structure is formed as described above.

[0004]

In the conventional manufacturing method as described above, the polyimide resin film 24 is formed after the second metal wiring is formed and immediately before the cover silicon nitride film 27 is formed.
Since pre-baking is performed to remove water from the metal, lateral hillocks 25A are generated in the aluminum wiring 25 that constitutes the second metal wiring by this pre-baking, and a short circuit occurs between wirings, resulting in a product step. There was a problem that retention and reliability deteriorated. An object of the present invention is to provide a method of manufacturing a semiconductor device in which lateral hillocks in the second metal wiring are prevented and reliability is improved.

[0005]

According to a method of manufacturing a semiconductor device of the present invention, a step of forming a first metal wiring on an insulating film of a semiconductor substrate and coating the first metal wiring with a polyimide resin film. A step of forming a through hole in which the first metal wiring is exposed in the polyimide resin film,
A step of forming a second metal wiring having a laminated structure in which at least an upper layer is a heat-resistant metal layer on the polyimide resin film, and a step of forming an inorganic film on the entire surface including the second metal wiring And a step of removing this inorganic film by anisotropic etching to leave it so as to cover the side surface of the second metal wiring, and a step of prebaking the polyimide resin film and then forming an inorganic film on the entire surface. Is included.

Here, the polyimide resin film is represented by an aromatic tetracarboxylic dianhydride represented by the general formula [Chemical formula 1], a diamine represented by the [Chemical formula 2], and a [Chemical formula 3]. It is formed by applying a solution containing a polyamic acid silicon type intermediate formed by mixing and reacting with an aminosilicon compound, and heat treating at a temperature of 150 to 200 ° C.

[0007]

[Chemical 1]

[Chemical 2]

Wherein R ¹ represents a tetravalent carbocyclic aromatic group,
R ² is a carbocyclic aromatic group having 6 to 30 carbon atoms, R ³ and R
⁴ are independently an alkyl group having 1 to 6 carbon atoms or a phenyl group,
K is a value of 1 ≦ K ≦ 3.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a method of manufacturing a semiconductor device having a two-layer wiring structure in the order of steps as one embodiment of the present invention. First, as shown in FIG. 1A, a semiconductor element active portion is formed,
Further, a phosphorus glass film 2 is formed as a base insulating film by chemical vapor deposition, then a polysilicon electrode 3 is formed, and a phosphorus glass film 4 by chemical vapor deposition is formed on the entire surface.
Next, as shown in FIG. 3B, an opening 4a is provided in the phosphor glass film 4 on the polysilicon electrode 3 by known lithography and dry etching. Subsequently, as shown in FIG. 3C, an aluminum film having a thickness of about 1 μm is formed by the sputtering method, and the first aluminum wiring 5 is formed by etching the aluminum film by photolithography and dry etching.

Next, as shown in FIG. 2D, P is used to improve the adhesion by using a mixed gas of N ₂ NH ₃ SiH _4.
Using the CVD method, the flow rate of N ₂ is 1 SLM, the flow rate of NH ₃ is 300 SCCM, the flow rate of SiH ₄ is 0.87 SLM, and the pressure is 0.
Film thickness 1500 with 36TOW, temperature 300 ℃, applied voltage 1KW
A Å silicon nitride film 6 is formed. Furthermore, a coating solution obtained by mixing and reacting an aminosilicon compound, a diamine, and an aromatic tetracarboxylic dianhydride was spin-coated at 2000 rpm for 30 seconds, and heat-treated at 200 ° C. for 30 minutes in a nitrogen gas atmosphere,
A polyimide resin film 7 is formed by applying heat treatment at 400 ° C. for 1 hour in a nitrogen gas atmosphere. Next, as shown in FIG. 6E, photolithography and CF ₄ , O _{2 are performed.}
CF using reactive ion etching using mixed gas
The flow rate of ₄ is 20 SCCM, the flow rate of O ₂ is 20 SCCM, the pressure in the chamber is 5 pa, and the applied power is 300 W. The polyimide resin film 7 is provided with through holes 7a.

Subsequently, as shown in FIG. 3F, an aluminum film having a thickness of about 1 μm and a titanium nitride film having a thickness of 0.1 μm are formed by the sputtering method, and the second aluminum wiring 8 is formed by photolithography and dry etching. Then, a second metal wiring having a laminated structure including the titanium nitride film 9 is formed.

Next, as shown in FIG. 3G, a silicon nitride film 10 having a film thickness of 3000 Å is formed on the entire surface by P-CVD. Then, as shown in FIG. 6H, reactive ion etching using CF ₄ gas is used, and the flow rate of CF ₄ is 20 SCCM,
The pressure is 5 pa and the applied power is 300 W, and the silicon nitride film 10 is etched back to form the silicon nitride film 10 only on the side wall of the wiring. Then, as shown in (i) of the figure, PC
After prebaking at 320 ° C. for 1 hour in a VD apparatus to remove water from the polyimide resin film 7, P-CVD is performed.
A two-layer wiring structure is formed by forming a cover silicon nitride film 11 having a film thickness of 1 μm using the method.

Here, the above-mentioned polyimide resin film 7 is
The coating solution is prepared by mixing and reacting an aminosilicon compound, a diamine, and an aromatic tetracarboxylic dianhydride. As the aminosilicon compound, P-aminophenyltrimethoxysilane represented by [Chemical Formula 4] is used. Is used. Further, diaminodiphenyl ether is used as the diamine, and benzophenonetetracarboxylic dianhydride is used as the aromatic tetracarboxylic dianhydride. The molar concentration of P-aminophenyltrimethoxysilane is 40%, dimethylacetamide is used as the solvent, and the viscosity of this solution is 300 cm · poise.

[0013]

[Chemical 4]

[0014]

As described above, according to the present invention, the second metal wiring has a laminated structure using a heat resistant metal as an upper layer,
Moreover, since the side wall is covered with an inorganic film, lateral hillocks may be generated in the aluminum alloy used for the second metal wiring even if baking is performed to remove water in the polyimide resin that is the interlayer film. In other words, there is an effect that short-circuiting between wirings can be suppressed and product yield and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a manufacturing method of the present invention in the order of manufacturing steps.

FIG. 2 is a sectional view showing a conventional manufacturing method in the order of manufacturing steps.

FIG. 3 is a cross-sectional view showing a conventional problem.

[Explanation of symbols]

 1 Semiconductor Substrate 2,4 Phosphorous Glass 3 Polysilicon Electrode 5 First Aluminum Wiring 6 Silicon Nitride Film 7 Polyimide Resin Film 8 Second Aluminum Wiring 9 Titanium Nitride Film 10,11 Silicon Nitride Film

Claims (2)

[Claims] 1. A step of forming a first metal wiring on an insulating film of a semiconductor substrate, a step of coating the first metal wiring with a polyimide resin film, and a step of coating the polyimide resin film with the first metal wiring. And a step of forming a second metal wiring having a laminated structure in which at least an upper layer of the heat resistant metal layer is formed on the polyimide resin film; A step of forming an inorganic film on the entire surface including the metal wiring, a step of removing this inorganic film by anisotropic etching and leaving it so as to cover the side surface of the second metal wiring, and a pre-baking for the polyimide resin film. A method of manufacturing a semiconductor device, comprising a step of forming an inorganic film on the entire surface after the step. 2. The polyimide resin film has a general formula:
A polyamic acid silicon type intermediate formed by mixing and reacting an aromatic tetracarboxylic dianhydride represented by the formula (4), a diamine represented by the formula (2) and an aminosilicon compound represented by the formula (3) The method for manufacturing a semiconductor device according to claim 1, wherein the solution containing the body is applied and heat-treated at a temperature of 150 ° C to 200 ° C. [Chemical 1] [Chemical 2] [Chemical 3] However, R ¹ represents a tetravalent carbocyclic aromatic group, R ² is a carbocyclic aromatic group having 6 to 30 carbon atoms, and R ³ and R ⁴ are independently an alkyl group having 1 to 6 carbon atoms. Or phenyl group, K is 1 ≦
It is a value of K ≦ 3.