JPH05129302A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To prevent a pinhole from being produced in a gold-plated film and to prevent an electrode film at the lower layer from being corroded in a gold- plated interconnection. CONSTITUTION:Titanium 102 and platinum 103 as an electrode film for plating use are formed on an Si substrate 101; a desired pattern is formed by a photoresist. In addition, while the electrode film is used as an electrode, an Ni-plated film 104 is formed in a part where the resist does not exist; in succession, a gold-plated film 105 is formed, at a pH of 4, on the Ni-plated film. When the Ni-plated film is formed at the lower layer before the gold-plated film is formed, it is possible to prevent a pinhole from being produced in the gold-plated film and to prevent the electrode film at the lower layer from being corroded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring structure of a semiconductor device, and more particularly to a wiring forming method by a plating method.

[0002]

2. Description of the Related Art A conventional semiconductor device and its manufacturing method are
Since the electrode film titanium and platinum were directly plated with gold, and the pH of the plating solution was 7 to 8, pinholes were easily generated in the gold plating film. Therefore, if there were pinholes in the gold plating film, gold would be ionized. Since the tendency was small, the lower electrode film was corroded to increase the contact resistance and reduce the reliability.

This will be described with reference to the conventional steps. First, in FIG. 3, titanium 302 and platinum 303 are formed as a first electrode film for plating on a Si substrate 301, and a first photoresist is used to form a film. A desired pattern is formed on the first electrode film.

Subsequently, plating is performed using the first electrode film, a first gold plating film 304 is formed on a portion where the first photoresist does not exist, and the first photoresist is removed. .. Further, the first electrode film is etched using the first gold plating film as a mask.

Next, an oxide film 305 is formed as an interlayer insulating film, and a hole portion is provided on the first gold plating film by photoetching.

Subsequently, titanium 306 and platinum 307 are formed on the oxide film as a second electrode film for plating.
Furthermore, a second photoresist having a desired pattern is formed on the second electrode film, plating is performed using the second electrode film, and a portion where the second photoresist does not exist, A second gold plating film 308 is formed.

Finally, the second photoresist is removed, and the second electrode film is etched using the second gold plating film as a mask.

The above is the conventional process.

[0009]

However, in the above-mentioned conventional technique, the electrode film titanium and platinum were directly plated with gold, and the pH of the plating solution was 7 to 8. Therefore, pinholes were generated in the gold plating film. Therefore, if there is a pinhole in the gold-plated film, gold has a small ionization tendency, so the electrode film in the lower layer is corroded, the contact resistance increases, and the reliability decreases.

Therefore, the present invention solves such a problem, and an object of the present invention is, when forming a gold plating film, plating Ni on the lower layer of the gold plating film and further adjusting the pH of the plating solution to 3 to 10. By setting the number to 5, the occurrence of pinholes can be prevented and a more reliable semiconductor device can be formed.

[0011]

The semiconductor device of the present invention comprises:
It is characterized in that the plurality of wiring layers formed by using the plating method are multilayer wiring layers in which a Ni plating film is formed between the gold plating film and the lower electrode film.

The method of manufacturing a semiconductor device of the present invention is
a) a step of forming titanium and platinum as a first electrode film for plating on a semiconductor substrate, and b) a step of forming a desired pattern on the first electrode film with a first photoresist, c) Ni plating using the first electrode film as an electrode to form a first Ni plating film on a portion where the first photoresist does not exist, and d) Electrode the first electrode film. As a step of forming a first gold-plated film on the first Ni-plated film by performing gold-plating in a pH range of the plating solution of 3 to 5, and e) a step of removing the first photoresist. , F) a step of etching the first electrode film using the first gold plating film and the Ni plating film as a mask, and g) forming an oxide film as an interlayer insulating film, and photoetching the first electrode film. Hole on gold plating film And h) forming titanium and platinum as a second electrode film on the insulating film and the first gold plating film, and i) forming a desired pattern on the second electrode film. Forming a second photoresist, and j) performing Ni plating using the second electrode film as an electrode, and forming a second Ni plating film on a portion where the second photoresist does not exist. And k) a step of forming a second gold-plated film on the second Ni-plated film by performing gold-plating with the second electrode film as an electrode in a pH range of 3 to 5 of the plating solution. l) a step of removing the second photoresist, and m) a step of etching the second electrode film using the second gold plating film as a mask.

[0013]

According to the above structure of the present invention, after the electrode film is formed, the Ni plating film is formed on the electrode film, the gold plating film is formed, and the pH of the Au plating solution is set to 3 to 5. It is possible to prevent the occurrence of pinholes in the gold plating film, improve the hardness of the plating film, suppress migration, and configure a semiconductor device with higher reliability.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device of the present invention has the structure shown in FIG.

101 is a Si substrate, 102 is titanium (T
i), 103 is platinum (Pt), 104 is a Ni plating film,
Reference numeral 105 is a gold plating film, 106 is an oxide film, 107 is titanium, 108 is platinum, 109 is a Ni plating film, and 110 is a gold plating film. The details will be described below by following FIGS. 2 (a) to 2 (m).

First, Ti (15 nm) 202 is formed on the entire surface of the Si substrate 201 as a first electrode film for plating, and further Pt (100 nm) 203 is formed.
(FIG. 2A) Next, a desired pattern is formed on the first electrode film by the first photoresist 204. (FIG. 2 (b)) Subsequently, plating is performed using the first electrode film as an electrode,
A first Ni plating film 205 is formed on a portion where the first photoresist does not exist. (FIG. 2 (c)) Furthermore, using the first electrode film as an electrode, the plating solution temperature 60
Gold plating is performed under the condition of ℃. At this time, the pH of the plating solution
Is 4 and the film thickness is 500 nm on the first Ni plating film.
The first gold-plated film 206 is formed. (FIG. 2D) Further, the first photoresist is removed (see FIG.
(E)) Using the first gold plating film and the first Ni plating film as a mask, the first electrode film is etched. (FIG. 2F) Next, an oxide film 207 is formed as an interlayer insulating film. At this time, TEOS (Si (OC
₂ H ₅ ) ₄ ) to remove the oxide film in plasma to 500 nm
Form. A hole portion is provided on the first gold-plated film by photoetching in the interlayer insulating film thus formed. (FIG. 2G) Subsequently, Ti (15 nm) 208 is formed as a second electrode film on the interlayer insulating film and the first gold plating film, and Pt (100 nm) 209 is further formed. (FIG. 2 (h)) Next, a second photoresist 210 having a desired pattern is formed on the second electrode film (FIG. 2 (i)).
A second N is formed on the portion where the second photoresist does not exist.
The i-plated film 211 is formed. (FIG. 2 (j)) Furthermore,
A second gold plating film 212 is formed on the second Ni plating film. (FIG. 2 (k)) Finally, the second photoresist is removed (see FIG.
(L)) The second electrode film is etched using the second gold plating film as a mask. (FIG. 2 (m)) In comparison with the conventional semiconductor device, the semiconductor device of the present invention thus formed has pin holes generated by plating Ni on the lower layer of the gold plating film and further setting the pH of the plating solution to 4. And the corrosion of the lower electrode film can be prevented.

The pH of about 3 to 5 is effective.

[0018]

As described above, according to the present invention, as compared with the conventional structure, the lower layer of the gold plating film is plated with Ni and the pH of the plating solution is set to 4 to prevent the occurrence of pinholes. It is possible to provide a more reliable semiconductor device that can prevent corrosion of the lower electrode film.

[Brief description of drawings]

FIG. 1 is a main cross-sectional view showing a semiconductor device of the present invention.

2A to 2M are cross-sectional views of the manufacturing process of the present invention.

FIG. 3 is a cross-sectional view showing a conventional semiconductor device.

[Explanation of symbols]

101, 201, 301 ... Si substrate 102, 202, 302 ... Titanium (Ti) 103, 203, 303 ... Platinum (Pt) 204 ... Resist 104, 205 ... Nickel plated film 105, 206, 304 ... Gold plated film 106, 207, 305 ... Oxide film (SiO ₂ ) 107, 208, 306 ... Titanium (Ti) 108, 209, 307 ... Platinum (Pt) 210 ... Resist 109, 211 ・ ・ ・ Nickel plated film 110, 212, 308 ・ ・ ・ Gold plated film

Claims (2)

[Claims] 1. A semiconductor device, wherein a plurality of wiring layers formed by a plating method is a multilayer wiring layer in which a Ni plating film is formed between a gold plating film and a lower electrode film. 2. A step of forming titanium and platinum as a first electrode film for plating on a semiconductor substrate, and b) using a first photoresist to form a desired electrode on the first electrode film. A step of forming a pattern, c) Ni plating using the first electrode film as an electrode, and forming a first Ni plating film on a portion where the first photoresist does not exist, d) Using the first electrode film as an electrode, gold plating is performed within a pH range of the plating solution of 3 to 5,
a step of forming a first gold plating film on the i plating film,
e) a step of removing the first photoresist, and f)
Etching the first electrode film using the first gold plating film and the first Ni plating film as a mask;
g) a step of forming an oxide film as an interlayer insulating film and providing a hole portion on the first gold plating film by photoetching; and h) a second electrode on the insulating film and the first gold plating film. Forming titanium and platinum as a film, i) forming a second photoresist having a desired pattern on the second electrode film, and j) using the second electrode film as an electrode Ni plating is performed, and a step of forming a second Ni plating film on a portion where the second photoresist does not exist; k) Using the second electrode film as an electrode, the pH of the plating solution is 3 to 5; Gold plating in the range,
Forming a second gold plating film on the second Ni plating film; l) removing the second photoresist; and m) using the second gold plating film as a mask A method for manufacturing a semiconductor device, comprising the step of etching the electrode film.