JPH0465166A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To effectively electrochemically treat at an independent part even if an electrode or a wiring is electrically independently disposed by conducting to the electrode or the wiring exposed from the opening of a conductive mask connected to an anode or cathode side. CONSTITUTION:In a glass board l formed with a conductive mask 4, a continuous wiring 2 exposed from the opening 5 of a mask 4 and an independent wiring 3 are conducted through the mask 4 connected to an anode + side. Thus, the wiring 2 and the wiring 3 can effectively be anodized in predetermined positions irrespective of whether a gate electrode and a lower wiring of a MOS type transistor are electrically independently disposed or not. Accordingly, since an insulating layer interposed between the electrodes or between the upper and lower wirings is formed in a 2-layer structure of a silicon nitride film and a tantalum oxide film, its insulating strength is enhanced to improve yield at the time of manufacturing and its withstand voltage can be improved.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device in which a substrate is provided with an electrode or a wiring portion made of a metal film, and in particular, the present invention relates to a method for manufacturing a semiconductor device in which a substrate is provided with an electrode or a wiring portion made of a metal film, and in particular, the present invention relates to a method for manufacturing a semiconductor device in which a substrate is provided with an electrode or a wiring portion made of a metal film. The present invention relates to a method of manufacturing a semiconductor device subjected to electrochemical treatment.

[Conventional technology]

As an example of this type of semiconductor device, for example, a thin film type semiconductor device will be explained. As shown in FIGS. a gate electrode (G) made of chromium or the like; a gate insulating film (b) made of silicon nitride (SiN) covering the gate electrode (G); A device is known in which the main part is composed of a thin amorphous silicon film (C) that acts, and a source electrode (S) and a drain electrode (D) connected to both ends of this amorphous silicon film (C). There is.

In this thin film semiconductor device, a drain voltage (V, ) is applied between the source electrode (S) and the drain electrode (D), and a predetermined gate voltage (v6) is applied to the gate electrode (G). By applying this voltage, a channel is formed in the amorphous silicon film (C) and the amorphous silicon film (C) is turned on, and the drain current (I D) flows, while the gate voltage (C) is
When VG) is lowered to below the threshold voltage VrHj, the semiconductor device turns off and the drain current (I,)
For example, it is incorporated into a contact type image sensor shown in FIGS. 15 to 16 and used for driving the sensor.

Incidentally, in this type of semiconductor device, the gate electrode (G) and the source electrode (S) are connected via the gate insulating film (b).
) ・Due to the fact that the drain electrode (D) and the drain electrode (D) are insulated from each other, the gate electrode (G
) and the source electrode (S) and drain electrode (D), and this discharge phenomenon causes the gate insulating film (b
) causes dielectric breakdown at the pinhole part of the gate electrode (G), source electrode (S), and drain electrode (D).
This has the disadvantage that the yield during manufacturing tends to drop because of short circuits between the two.

Note that the above-mentioned discharge phenomenon does not occur only between the gate electrode (G) and the source electrode (S)/drain electrode (D); for example, when an insulating layer is interposed as shown in FIG. A similar phenomenon occurs between the upper wiring (dl) and the lower wiring (d2) of the multilayer wiring structure.

For this reason, conventionally, the gate electrode (G) is anodized as shown in FIG.
As shown in FIG. 18, each electrode is In other words, the insulating layer interposed between the wirings has a two-layer structure consisting of the insulating film and the anodic oxide film (f) to increase its insulating strength and prevent a decrease in yield.

[Problem to be solved by the invention]

By the way, when electrochemical treatment such as anodic oxidation is performed on appropriate parts of the gate electrode (G) and the lower wiring (d2), conventionally, the substrate (
A) is immersed in the anodizing treatment tank (h) as shown in Figure 19, and the anodizing treatment is carried out by applying electricity with the electrodes, wiring (d), etc. connected to the anode (+) side. A method was adopted to do so.

In FIG. 19, the electrode or wiring (d) region that is not subjected to anodization treatment is covered with a resist film not shown.

Further, (g) is a counter electrode made of platinum (Pt) or the like.

However, with this conventional method, when the electrodes and wiring (d) are electrically isolated in a wiring pattern as shown in Figure 20, it is impossible to conduct electricity to these isolated parts, so anodic oxidation is required. There was a problem that it became impossible to perform electrochemical treatments such as

On the other hand, in the past, a metal film constituting the electrodes, wiring (d), etc. is uniformly formed, and after electrochemical treatment such as anodic oxidation is performed, this metal film is applied to the electrodes, wiring (d), etc.
) method is also used in some cases, but when such a method is used, areas that do not require that treatment are also subjected to anodizing treatment, which means that the metal film is As the wiring becomes thinner, the conductivity of the wiring (d) and the like decreases, resulting in a new problem that the operating speed thereof is delayed.

[Means to solve the problem]

The present invention has been made in view of the above-mentioned problems, and its object is to ensure that even when electrodes or wiring parts are electrically isolated, the isolated parts can be electrochemically An object of the present invention is to provide a method for manufacturing a semiconductor device that can be processed.

That is, the present invention is based on a method for manufacturing a semiconductor device in which a substrate is provided with an electrode or a wiring portion formed of a metal film and subjected to an electrochemical treatment on the surface thereof, a metal film is uniformly formed on the substrate, and a metal film is uniformly formed on the substrate. , an electrode or wiring part forming step of processing the metal film into the shape of an electrode or wiring part; a lamination step of laminating a conductive film made of a conductive material on the substrate on which the electrode or wiring part is formed; A mask forming step in which openings are formed in appropriate parts of the conductive film to turn the conductive film into a conductive mask, and the conductive mask is connected to the anode or cathode side of the substrate on which the conductive mask is formed. an electrochemical treatment step of electrochemically treating the surface of the electrode or wiring portion exposed through the opening of the conductive mask by immersing the conductive mask in an electrochemical treatment tank in a state where the conductive mask is be.

In such a technical means, the following metal materials can be used as the metal film constituting the electrode or wiring section. That is, tungsten,
High melting point metals such as molybdenum, titanium, tantalum, and cobalt, high melting point alloys such as tantalum molybdenum alloy (TaMo), tantalum tungsten alloy (TaW), and tantalum mixed with nitrogen ions as impurities can be used. Note that a low melting point metal such as aluminum can be used as the metal film formed in a portion that is rarely exposed to high-temperature heat treatment, such as the upper wiring.

In addition, ordinary photolithography and etching methods can be used as means for processing this metal film into the shape of electrodes or wiring parts, and dry etching or etching may also be used depending on the metal material used. Wet etching can be applied.

Next, as the conductive material to be laminated in the lamination step, metal materials such as aluminum, conductive photoresist materials, conductive polyimide resins, etc. can be used. Note that when the above-mentioned metal material is used as the conductive material, it is desirable to pay attention to the following points in relation to the metal material constituting the electrode or wiring section. That is,
From the viewpoint of efficiently progressing the electrochemical treatment to the metal film constituting the electrode or wiring part, the metal material constituting the conductive film is more likely to undergo anodic oxidation etc. than the metal material constituting the electrode or wiring part. It is desirable that the material be difficult to undergo electrochemical treatment. Furthermore, when a conductive photoresist material, conductive polyimide resin, or the like is used as the conductive material, it is desirable to adjust its conductivity as appropriate depending on the electrochemical treatment conditions such as anodic oxidation.

In addition, the electrochemical treatment performed on the surface of the electrode or wiring part in this technical means includes anodization treatment in which the substrate on which the conductive mask is formed is immersed in an anodization treatment tank. This also includes metal plating processing in which a substrate on which a conductive mask is formed is immersed in a metal plating tank.

The scope of application of this technical means includes the manufacture of thin film semiconductor devices that utilize amorphous silicon, polysilicon films, etc. formed on insulating substrates such as glass substrates, as well as the manufacture of thin film semiconductor devices that utilize single crystal silicon substrates, etc. Usual MO used
Naturally, the present invention can also be applied to the manufacture of S-type and bipolar-type semiconductor devices.

[Effect]

According to the above-mentioned technical means, an electrode or wiring part forming step of uniformly forming a metal film on a substrate and processing this metal film into the shape of an electrode or wiring part; a lamination step of laminating a conductive film made of a conductive material on the substrate formed with the above conductive film, and a mask forming step of forming openings at appropriate parts of the conductive film to use the conductive film as a conductive mask. The substrate on which the conductive mask is formed is immersed in an electrochemical treatment tank with the conductive mask connected to the anode or cathode side, and the electrode or wiring portion exposed from the opening of the conductive mask. An electrochemical treatment step for electrochemically treating the surface of Therefore, even in the case of a wiring pattern in which the electrodes or wiring portions are electrically isolated, it is possible to reliably perform electrochemical treatment on the isolated electrodes or wiring portions. .

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, an embodiment in which the present invention is applied to a thin film MO3 type transistor will be described in detail with reference to the drawings.

◎First Example First, a tantalum metal film is formed on a glass substrate (1) by sputtering, and this is patterned to form gate electrodes and lower wiring as shown in Figures 1 and 2. A continuous wiring portion (2) and an isolated wiring portion (3) are formed.

Next, as shown in FIGS. 3 to 4, an aluminum film (40) is formed in a --like pattern on this surface, and by photolithography and wet etching, as shown in FIGS. As shown in FIG. 6, openings (5) are provided in portions corresponding to the anodic oxide film forming regions of the continuous wiring portion (2) and the isolated wiring portion (3), respectively, and the aluminum film (40) is formed.
is used as a conductive mask (4).

Then, as shown in FIG. 12, the glass substrate (1) on which the conductive mask (4) is formed is immersed in an anodizing tank (6) filled with an aqueous citric acid solution, and the conductive mask (4) is Anodizing is performed with the mask (4) connected to the anode (+) side and the platinum counter electrode (7) placed facing the glass substrate (1) connected to the cathode (-) side. 7th
As shown in Fig. 8, the opening (5) of the conductive mask (4)
) Continuous wiring part (2) and isolated wiring part (3) exposed from
An anodized film (8) of Tag is formed on the surface of the tag.

Next, the entire surface is etched to remove the conductive mask (4) as shown in FIGS. 9 and 10, and the partially anodized continuous wiring part (2) and isolated wiring part (3) are removed. After exposing this surface, a gate insulating film (not shown) of silicon nitride film (SiN) is formed on this surface by plasma CVD method, and then an amorphous silicon film, source/drain film is formed according to the usual process. Electrodes, upper wiring, etc. were formed to obtain a thin film MO3 type transistor.

In this way, according to the manufacturing method according to the example, the anode (+)
A continuous wiring portion (
2) and the isolated wiring part (3), regardless of whether the gate electrode and the lower wiring in the MO3 transistor are electrically isolated, the continuous wiring part (2) Thus, it is possible to reliably perform anodic oxidation treatment on a predetermined portion of the isolated wiring portion (3).

Therefore, the insulating layer interposed between the upper wiring and the lower wiring for each electrode has a two-layer structure of silicon nitride film and tantalum oxide film, which increases the insulation strength and improves the manufacturing yield. It also has the advantage of improving voltage resistance.

Moreover, according to this method, only the necessary parts of the continuous wiring part (2) and the isolated wiring part (3) can be selectively anodized, and as shown in FIGS. Since the film loss in the continuous wiring part (2) and the isolated wiring part (3) due to oxidation treatment can be minimized, the increase in wiring resistance due to this film loss is reduced, which also prevents delays in operation speed. It has the advantage of being able to

Further, the continuous wiring section (2) is connected through the conductive mask (4).
) and all parts of the isolated wiring section (3) are electrically connected, so the anodizing treatment tank (6
) in the anode (+) side electrode and each wiring part (2) (
3) has the advantage of facilitating connection operations.

◎Second Example This example differs from the manufacturing method of the first example except that a conductive photoresist was used as the constituent material of the conductive mask.

The conductive photoresist was sufficiently post-baked at a temperature of 120° C. or higher before being immersed in the anodizing bath.

Also, in the manufacturing method according to this embodiment, as in the first embodiment, the yield and withstand voltage during manufacturing can be improved.
In addition, this embodiment has the advantage that delays in operation speed can be prevented, and the process of removing the conductive mask is simpler than that of the first embodiment.

〔Effect of the invention〕

According to the present invention, it is possible to conduct electricity to the electrode or wiring section exposed from the opening of the conductive mask through the conductive mask connected to the anode side or the cathode side. Even in the case of a wiring pattern in which electrodes or wiring portions are electrically isolated, it is possible to reliably perform electrochemical treatment on the isolated electrodes or wiring portions.

Therefore, for example, when anodizing the electrodes or wiring parts, it is possible to improve the yield and withstand voltage during manufacturing, and also to minimize the loss of film in the wiring parts, etc. This also has the effect of preventing delays in operating speed.

[Brief explanation of the drawing]

1 to 12 show embodiments of the present invention.
The figure is a partial perspective view of a glass substrate on which a continuous wiring part and an isolated wiring part are formed, FIG. 2 is a plan view of FIG. Fig. 4 is a plan view of Fig. 3, Fig. 5 is a perspective view of a state in which a conductive mask is formed, Fig. 6 is a plan view of Fig. 5, and Fig. 7 is a state of anodizing treatment. 8 is a plan view of FIG. 7, FIG. 9 is a perspective view with the conductive mask removed, FIG. 10 is a plan view of FIG. 9, and FIG. 11 (A) is a plan view of FIG. 11(B) is a sectional view taken along the plane XIB-XIB of FIG. 9, and FIG. 12 is a schematic perspective view of the anodizing treatment tank. Figure 13 ~ 2nd
Fig. 0 shows a conventional example, Fig. 13 is a schematic perspective view of a thin film type semiconductor device, and Fig. 14 shows the XIVXIV of Fig. 13.
15 is a schematic perspective view of a contact type image sensor incorporating this semiconductor device, FIG. 16 is a plan view of FIG. 15, and FIG. 17 is a thin film type image sensor in which the gate electrode is anodized. FIG. 18 is a cross-sectional view of a semiconductor device, and FIG. 19 is a plan view of a multilayer wiring structure in which a portion of the lower wiring is anodized.
Figures 1 to 20 are schematic perspective views of the anodizing tank used for the treatment. [Explanation of symbols] (1)...Glass substrate (2)...Continuous wiring section (3)...Isolated wiring section (4)...Conductive mask (5)...Opening (6) ...Anodic oxidation treatment tank Figure 1 Figure 2 Glass substrate patent Applicant: Fuji Serotox Co., Ltd. Agent
Patent Attorney Tomohiro Nakamura (2 others) Figure 4υ Figure Figure 4 Conductive mask Figure 10 Figure 11 Figure 13 Figure 14 Figure 12 Figure Anodizing treatment Figure 17 f Figure 18 Figure 19

Claims (1)

[Scope of Claims] A method for manufacturing a semiconductor device in which a substrate includes an electrode or a wiring portion formed of a metal film and subjected to an electrochemical treatment on the surface thereof, wherein a metal film is uniformly formed on the substrate, and an electrode or wiring part forming step in which the metal film is processed into the shape of an electrode or wiring part; a lamination step in which a conductive film made of a conductive material is laminated on the substrate on which the electrode or wiring part is formed; A mask forming step in which openings are formed at appropriate locations in the conductive film to turn the conductive film into a conductive mask, and the conductive mask is connected to the anode or cathode side of the substrate on which the conductive mask is formed. an electrochemical treatment step in which the semiconductor device is immersed in an electrochemical treatment tank while the semiconductor device is in an electrochemical treatment bath, and the surface of the electrode or wiring portion exposed through the opening of the conductive mask is electrochemically treated. Production method.