JPH0334431A - Wiring method of semiconductor device - Google Patents

Abstract

PURPOSE:To firmly form a wiring part constituted of aluminum and additive metal diffused in said aluminum without generating the segregation of the additive metal, by providing insulating film forming process, surface activating process, aluminum based alloy coating film forming process, and wiring part forming process, for a substrate on which a group of semiconductor elements is formed. CONSTITUTION:On a silicon substrate 1 on which a group of semiconductor elements is formed, polyimide resin is spread, and a coating film for an insulating film is stuck, thereby forming an insulating film 2. Said substrate is accommodated in a parallel flat plates type RF plasma ashing apparatus 3, and nitrogen ion bombardment processing is performed, thereby roughening and cleaning the surface. Next, said substrate is accommodated in a DC magnetron sputtering apparatus, and aluminum alloy is stuck on the surface of the insulating film 2, thereby forming an aluminum based alloy coating film 4. A resist film 5 corresponding with a wiring pattern is formed: the aluminum based alloy coating film 4 exposed from the resist film 5 is etched, and the resist film 5 also is eliminated, thereby forming a wiring part 6 constituted of copper-added aluminum.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a wiring method for a semiconductor device having a group of semiconductor elements such as MO8 type or bipolar type on a substrate, and in particular, the present invention relates to a wiring method for a semiconductor device having a group of semiconductor elements such as MO8 type or bipolar type on a substrate. This invention relates to an improvement in a wiring method in which an additive metal diffused into aluminum and a -C structure are used.

[Prior Art] For example, as shown in FIG. 4, this type of semiconductor device includes a substrate (a), a group of semiconductor elements (not shown) provided on the substrate (a), and polyimide resin, etc. Insulation made of organic polymer 1! A device is known in which the main part thereof is constituted by a wiring part (C) connected at the electrical connection part of the semiconductor element group through (b), and this wiring part (C)
Aluminum is widely used as a constituent material due to its excellent conductivity and workability.

However, when the wiring part (C) is formed on the insulating film (b) made of an organic polymer, the adhesion between the constituent aluminum and the organic polymer is weak, so it may be necessary to remove the wiring after etching or passivation. There was a drawback that the wiring portion (C) was easily peeled off from the insulation wA(b) when subjected to high stress from a film (not shown).

For this reason, conventionally, as shown in FIG. 5(A), an insulating film (b) made of an organic polymer such as polyimide resin
was deposited on the substrate (a), and then the substrate (a) was
℃, and in this state, an aluminum film (C゛〉) for forming the wiring part (C) is deposited by sputtering, thereby forming the insulating film (b) and the aluminum film 111 (c).
') was aimed at improving the adhesion between the two (see Figure 5B).

Note that the strongly deposited aluminum film (c') is processed into a shape corresponding to the wiring pattern according to the usual photolithography method, and a wiring part (C) as shown in Fig. 5 (C) is formed. It was something to do.

[Problems to be Solved by the Invention] By the way, even if the wiring portion (C) is firmly formed on the insulation II (b) made of an organic polymer by such a method, the wiring portion (C) Compared to other metals, the aluminum that makes up the
Since aluminum is easily susceptible to migration, the wiring part (C) may be cut at the migrated area, and since aluminum has strong diffusivity, it may not be suitable for the insulation film (b) or substrate (
This has the disadvantage that it may diffuse toward the a) side, which tends to impair the functionality of the semiconductor device.

For this reason, conventionally, the above-mentioned migration has been prevented by including additive metals such as copper (Cu) and silicon (S i ) in the aluminum constituting the wiring portion (C).

However, insulating film that is heated according to the conventional method is an aluminum-based alloy film containing metals such as copper and silicon.
(b) When deposited on the insulating film (b), additive metals such as copper and silicon in the aluminum alloy film
Thermal energy may be received from the etching and segregated at the interface with the insulating film (b), which may cause after-corrosion problems when forming the wiring part (C) corresponding to the wiring pattern by etching. , there were problems such as reduced migration resistance.

[Means for Solving the Problems 1] The present invention has been made in view of the above-mentioned problems, and its object is to provide aluminum and the diffusion into this aluminum on a substrate on which a group of semiconductor elements is formed. An object of the present invention is to provide a wiring method that can firmly form a wiring section made up of an additive metal and an additive metal without causing segregation of the additive metal.

That is, the present invention provides a semiconductor device in which a wiring section made of aluminum and an additive metal diffused into the aluminum is formed on a substrate on which a group of semiconductor elements is formed, through an insulating film made of an organic polymer. Assuming the wiring method, an insulating film forming step of forming an insulating film made of an organic polymer on the substrate on which the above-mentioned semiconductor element group is formed with the electrical connection portions of each semiconductor element exposed; A surface activation treatment step in which the surface of the film is roughened and cleaned, and an aluminum-based alloy film composed of aluminum and an additive metal is uniformly applied on the activated insulating film at room temperature. a wiring part forming step of processing this aluminum alloy film into a shape according to a wiring pattern and forming a wiring part connected at an electrical connection part of the semiconductor element group. , and.

In such technical means, the above-mentioned polyimide resin or the like can be used as the organic polymer constituting the insulating film.

Further, in the insulating film forming step, as a means for depositing the organic polymer on the substrate on which the semiconductor element group is formed, a method of applying a liquid polymer material and curing it, etc. can be applied.

Furthermore, in the surface activation treatment process, any means for roughening and cleaning the surface of the insulating film deposited on the substrate is optional. For example, nitrogen ions, argon ions are applied to the surface of the insulating film under vacuum conditions. An ion bombardment treatment method that performs this by irradiating with an inert gas such as can be applied.

In this case, by appropriately setting the internal pressure in the vacuum chamber in which the ion bombardment process is performed, the type of inert gas applied, the gas flow rate, power, processing time, etc., the insulating film made of the applied organic polymer can be Appropriate surface roughening and cleaning treatment can be performed to obtain sufficient adhesion with the aluminum alloy film.

Next, as additive metals added to aluminum,
In addition to the above-mentioned copper (Cu) and silicon (S i ), there are titanium (T i ), magnesium (Mg), tungsten (W), and the like. Moreover, the addition ratio of the above-mentioned additive metal to aluminum is set to an appropriate value based on the compatibility between aluminum and the additive metal.

In addition, in the process of forming an aluminum alloy film, sputtering is used as a method for uniformly depositing an aluminum alloy film composed of aldinium and a conversion metal on the activated insulating film. , vapor deposition, CVD (chemical vapor deposition), and the like can be applied. Further, the temperature conditions during deposition must be at room temperature, specifically in the range of 50° C. or lower, in order to prevent segregation of the conversion metal.

Next, in the wiring part forming process, the conventional method of processing the aluminum alloy film into a shape according to the wiring pattern is RIE (reactive ion
Etching method, sputtering method, wet etching method, etc. can be applied.

Further, regarding a substrate constituting a part of a semiconductor device, an MO8 type or bipolar type semiconductor element group is formed in or on the substrate.

[Operation] According to the above-mentioned technical means, the surface of the insulating film is roughened and cleaned in the surface activation treatment process, so that the insulating film is not heated and softened. That is, an aluminum alloy film composed of aluminum and an additive metal can be deposited on this insulating film at room temperature, and segregation of the conversion metal can be reliably prevented.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 1(A), a polyimide resin in a solution state is applied by a normal method onto a silicon (Sl) substrate (1) on which a group of semiconductor elements (not shown) is formed. After depositing an insulating film and then subjecting it to beta treatment at 165°C for 20 minutes, and creating openings (not shown) at the electrical connection parts of the semiconductor element group by photolithography, 230 C. for 90 minutes to form an insulation fi! (2) with a thickness of 1.5 μm.

Next, the silicon substrate (1) on which this insulating film (2) was formed
is housed in a parallel plate type RF plasma ashing device (3) as shown in FIG. 2, and the insulation 1! Regarding (2), as shown in FIG. 1(B), nitrogen ion bombardment treatment was performed to roughen and clean the surface.

In this case, the setting conditions for the ion bombardment treatment were as follows.

Inert gas applied: Nitrogen gas Flow rate of nitrogen gas: 200 sec Internal pressure inside the processing chamber: 0.6 torr Power: 1.0 W Processing time: 10 minutes In the figure, (31) is an electrode plate that holds the silicon substrate (1), (32) is an electrode plate provided opposite to this electrode plate (31), (33) is an exhaust hole connected to a vacuum pump, 〈34〉 denotes a valve provided in this exhaust hole (33〉), and 〈35〉 denotes a nitrogen gas inlet.

Next, the silicon substrate (1) subjected to ion bombardment treatment is placed in a DC magnetron sputtering apparatus, and the insulating film (2) is deposited under room temperature conditions.
1μ with 1% silicon and 0.5% copper added on the surface
To form an aluminum-based alloy skin PI (4) by depositing an aluminum alloy film of the same thickness as the door, see Fig. 1C>.

In this case, the setting conditions for the sputtering were as follows.

Room temperature conditions without heating the silicon substrate (1) > Internal pressure inside the device: 9.0 x 10' torr power density
...1114/ci Next, as shown in FIG. 1(D), a resist I corresponding to the wiring pattern is applied to the aluminum alloy film (4>
I! <5), and then the above-mentioned resist II! The aluminum-based alloy film (4) exposed from <5') is etched and the resist jl (5) is also removed, resulting in a wiring made of aluminum doped with copper as shown in FIG. 1(E). Section (6) was formed.

As described above, according to the wiring method according to the embodiment, the insulating film (2) deposited on the silicon substrate (1) is subjected to ion bombardment treatment to roughen and clean the surface. , without heating the silicon substrate (1), that is, at room temperature. J(
2) The aluminum alloy skin 11 (4) can be firmly adhered thereon, and segregation of the additive metals such as copper and silicon can be reliably prevented.

Therefore, it has the advantage that the wiring portion (6) made of aluminum and the additive metal can be formed firmly without reducing migration resistance or the like.

Furthermore, Fig. 3 is a graph showing the relationship between the ion bombardment treatment time and the rate of peeling of the wiring section (6) corresponding to this treatment time. If applied, the wiring part (6>
It can be confirmed that the peeling phenomenon can be prevented.

[Effects of the Invention] According to the present invention, since the surface of the insulating film is roughened and cleaned in the surface activation treatment process, the insulating film is not heated to a softened state, that is, it is not heated to room temperature. An aluminum-based alloy film composed of aluminum and an additive metal can be deposited on the insulating film below, thereby making it possible to reliably prevent segregation of the conversion metal.

Therefore, it is possible to strongly form a wiring portion made of aluminum and an additive metal without reducing migration resistance or the like.

[Brief explanation of drawings]

Figures 1 to 3 relate to embodiments of the present invention;
Figures (A) to (E) are process explanatory diagrams of the wiring method according to the embodiment, Figure 2 is a schematic configuration diagram of a plasma ashing device that performs ion bombardment processing, and Figure 3 is ion bombardment processing time and this processing. Graphs showing the relationship between the occurrence rate of peeling of the wiring part and time are shown, and FIG. 4 is a perspective view of a semiconductor device equipped with a conventional wiring part, and FIGS. C) shows a process explanatory diagram of a conventional wiring method. [Description of symbols] (1>... Substrate (2>... Insulating film (4)... Aluminum alloy film (5)... Resist film (6)... Wiring portion patent applicant Fuji Xerox Co., Ltd. Representative Patent Attorney Tomohiro Nakamura (2 others) Fig. 2 Fig. 0 Nitrogen ion bombardment treatment time (minutes) Fig. Fig.

Claims (2)

[Claims] (1) A wiring method for a semiconductor device in which a wiring section made of aluminum and an additive metal diffused into the aluminum is formed on a substrate on which a group of semiconductor elements is formed, via an insulating film made of an organic polymer. an insulating film forming step of forming an insulating film made of an organic polymer on the substrate on which the semiconductor element group is formed with the electrical connection portions of each semiconductor element exposed; A surface activation treatment process that roughens and cleans the surface, and an aluminum alloy film composed of aluminum and an additive metal is uniformly deposited on the activated insulating film at room temperature. an aluminum-based alloy film forming step; and a wiring portion forming step of processing the aluminum-based alloy film into a shape according to a wiring pattern to form a wiring portion connected at an electrical connection portion of the semiconductor element group. A wiring method for a semiconductor device, characterized in that: (2) The wiring method for a semiconductor device according to claim 1, wherein the surface activation treatment step comprises ion bombardment treatment in which the surface of the insulating film is irradiated with an inert gas. .