JPS63104424A - Manufacture of semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To realize the formation of a minute pattern by a method wherein, after a substance layer containing carbon has been formed by being irradiated by an electron beam in a vacuum whose degree of vacuum is comparatively low, this layer is used for an etching mask. CONSTITUTION:An organic film 9 is applied on an aluminum film 8 which is formed on an interlayer insulating film 7 formed on a semiconductor substrate 1. An inorganic film 10 is applied on this assembly. The semiconductor substrate 1 is put in a vacuum chamber where a gas containing carbon has been introduced; the surface of this inorganic film 10 is irradiated by an electron beam 11 by keeping the degree of vacuum in the chamber at a comparatively low level. With this process, a substance layer 12 containing carbon is formed on the surface of the inorganic film 10. The width of this substance layer 12 is extremely narrow, i.e. about the same as the diameter of the electron beam 11. After the inorganic film 10, the organic film 9 and the aluminum film 8 have been etched in succession by making use of this substance layer 12 as a mask, it is possible to form an extremely minute wiring part 14.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to semiconductor integrated circuit devices! ! This article relates to 12 manufacturing methods, and in particular, to photolithography, which is an effective technique that can be applied to form fine patterns that can be realized.

[Conventional technology]

2. Description of the Related Art Recently, in semiconductor integrated circuit devices, with the miniaturization of elements, techniques for forming fine patterns with submicron widths have become extremely important.

[Problem that the invention seeks to solve]

However, in the conventional exposure method using light, the width is 0.
It is impossible to form a fine pattern of about 5 μm or less. On the other hand, as an alternative technology to this light exposure method,
There is an exposure method using an electron beam with a shorter wavelength, but in this case, the resolution of the electron beam resist becomes lower than expected from the wavelength of the electron beam due to the effect of backscattering of incident electrons.

That is, there is a problem that miniaturization is restricted by the electron beam resists 1 to 1.

An object of the present invention is to provide a technique that can easily form an extremely fine pattern with a width comparable to the diameter of an electron beam.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

As a result of intensive studies to correct the drawbacks of the prior art as described above, the inventor of the present invention discovered that when an arbitrary surface is irradiated with an electron beam in a vacuum with a relatively poor degree of vacuum, the residual gas contained in the vacuum is The inventors have discovered that as a result of organic substances being decomposed by the electron beam and deposited on the surface, a fine material layer containing at least carbon is formed in the irradiated area, and based on this finding, the present invention has been devised. .

Outline of typical inventions disclosed in this application is as follows.

That is, a material layer containing at least carbon, which is formed by irradiating an electron beam in a relatively low degree of vacuum, is used as an etching mask.

[For production]

According to the above-mentioned means, it is possible to form an etching mask made of a fine material layer with a width comparable to the diameter of the electron beam. An extremely fine pattern with a width comparable to the diameter of the beam can be easily formed.

〔Example〕

The arrangement of the present invention will be described below based on one embodiment with reference to the drawings.

In all figures, parts having the same functions are denoted by the same reference numerals, and repeated explanations thereof will be omitted.

As shown in FIG. 1, first, by selectively thermally oxidizing the surface of a semiconductor substrate 1 such as a P-type silicon substrate, a field insulating film 2 made of a 5i02 film is formed to perform element isolation. On the surface of the active region surrounded by this field insulating film 2, insulating films 1 to 3, such as SiO2 films, are formed, and further on this gate insulating film 3, a gate electrode 4 made of, for example, a polycrystalline silicon film is formed. form. Next, using this gate electrode 4 as a mask, n-type impurities are ion-implanted into the semiconductor substrate l, thereby forming, for example, a II'' type source region 5 and drain region 6 in a self-alignment line with respect to the gate electrode Fi4.

Next, after forming an interlayer insulating film 7 such as a phosphosilicate glass (PSG) film or a 5102 film on the entire surface, predetermined portions of the interlayer insulating film 7 are removed by etching to form contact holes 7a and 7b.

Next, for example, an aluminum film 8 is formed on the entire surface by, for example, sputtering, and then an organic film 9 for planarization is applied on this aluminum film 8. The surface of the organic film 9 after this coating becomes flat. Next, a film thickness of, for example, 0 is applied on this organic film 9.
．． An inorganic film lO such as a spin-on glass (SOG) film with a thickness of about 1 μm is applied. Note that these inorganic films 10
The organic film 9 is not necessarily required and can be omitted if necessary.

Next, the semiconductor substrate 1 is placed in a vacuum chamber of an electron beam lithography apparatus, and the electron beam 1z 11 is placed in a relatively low vacuum state and the beam diameter is narrowed to, for example, about 0.5 to 0.01 μm. By scanning, the surface of the inorganic film 10 at a position corresponding to a wiring 12 to be described later is irradiated with the electron beam 11. As a result, organic substances such as hydrocarbons contained in the residual gas in the vacuum are decomposed by the irradiation of the electron beam 11 and deposited on the inorganic film 10, as shown in FIG. A material layer 12 containing at least carbon is formed on the surface of the inorganic film IO in the portion irradiated with the electron beam 11.

The width of this material layer 12 is approximately the same as the diameter of the electron beam 11, which is extremely small. Note that introducing a gas containing at least carbon, such as hydrocarbon, into the vacuum chamber,
Irradiation with the electron beam 11 may be performed in this state.

Next, as shown in FIG. 3, using this material layer 12 as a mask, the inorganic film 10 is subjected to, for example, dry etching to form a predetermined pattern of the inorganic film. In this case, the inorganic film IO is extremely thin and has a high selectivity to the material layer 12 during dry etching, so the material layer 12
It is possible to pattern the inorganic film 10 even if the thickness of the inorganic film 10 is small. Next, using this predetermined pattern as a mask, the organic film 9 is anisotropically etched in a direction perpendicular to the substrate surface by, for example, reactive ion etching (R, IE) to form a predetermined pattern made of an organic film. Using this predetermined pattern as a mask, the aluminum film 8 is anisotropically etched by, for example, RIE to form a wiring pattern 13. Of the wiring pattern 13 formed in this way, the wiring portion with a small width is
The width is approximately the same as the diameter of the electron beam 11, and therefore extremely fine wiring 13 can be formed.

Moreover, as shown in FIG. 1, a material layer 12 is formed by irradiating the surface of the inorganic film 10 in a region where the wiring 13 is to be formed with an electron beam 11, and using this as a mask, the inorganic film 10 and the organic film 9 are Since the wiring pattern 13 is formed by sequentially etching the aluminum film 8 and the aluminum film 8, the fine wiring 13 can be easily formed.

Thereafter, the inorganic film 10 and the organic film 9 are removed by etching to complete the intended semiconductor integrated circuit device as shown in FIG.

As above, the invention made by the present inventor has been specifically explained based on the above embodiments, but the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist of the invention. It is.

For example, in the above-mentioned embodiment, the case where the wiring pattern 13 of aluminum was formed was explained, but the present invention can also be applied to the case where various fine patterns other than wiring are formed. Furthermore, the present invention can be applied to various semiconductor integrated circuit devices that require the formation of fine patterns.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions will be briefly explained.

It is as follows.

That is, an extremely fine pattern with a width comparable to the diameter of the electron beam can be formed.

=7-

[Brief explanation of the drawing]

1 to 4 are cross-sectional views for sequentially explaining a method for manufacturing a semiconductor integrated circuit device according to an embodiment of the present invention. In the figure, 1... semiconductor substrate, 4... gate electrode, 7...
...Interlayer insulating film, 8...Aluminum film, 9...Organic film, 10...Inorganic film, 11...Electron beam, 12.
...Material layer, 13... Wiring pattern. A) Figure 4

Claims (1)

[Claims] 1. A semiconductor integrated circuit device characterized in that a material layer containing at least carbon, which is formed by irradiating an electron beam in a vacuum with a relatively low degree of vacuum, is used as an etching mask. manufacturing method. 2. The method of manufacturing a semiconductor integrated circuit device according to claim 1, wherein a gas containing at least carbon is introduced into the vacuum. 3. A patent claim characterized in that an organic film and an inorganic film are sequentially formed on the film to be etched, and the material layer is formed on the inorganic film by irradiating the inorganic film with the electron beam. A method for manufacturing a semiconductor integrated circuit device according to item 1 or 2.