JP2690378B2 - Method of forming fine pattern - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for forming a fine slit-shaped pattern in a semiconductor element manufacturing process.

(Prior Art) Conventionally, as a technology in such a field, there has been already proposed, for example, Japanese Patent Application No. 63-232699 filed by the applicant of the present application.

FIG. 2 is a sectional view of the conventional process of forming a fine pattern.

First, as shown in FIG. 2A, a material layer 2 and a resist 3 are continuously applied on a substrate 1, and then a reverse taper-shaped slit 4 having a width of about 0.5 μm is formed on the resist 3 by a light exposure method or the like. Patterning by.

After forming this pattern, as shown in FIG.
The Al film 5 as a vapor deposition mask material is vacuum vapor-deposited from a direction forming an angle θ with the vertical direction of the substrate 1. Then, a shadow portion 6 of the vapor deposition mask material in which slits are to be formed appears in the slit 4.

Therefore, as shown in FIG. 2C, a slit 8 is formed in the material layer 2 in the shadow portion 6 by performing anisotropic etching using the Al film 5 as the vapor deposition mask material as a mask. Then, a fine pattern is formed.

(Problems to be Solved by the Invention) However, according to the above-described conventional method of forming a fine pattern, it is difficult to control the slit 4 having the inverse taper shape of the pattern of the resist 3, and if the taper angle becomes large. , Other than the planned shadow portion 6 of the Al film 5,
On the opposite side of the slit pattern, another shadow portion 7 which is not planned to be covered with the Al film 5 is formed. Next, the material layer 2 is anisotropically etched, but it is difficult to completely anisotropically etch it. Therefore, there is a problem that the shadow portion 7 other than the shadow portion 6 is simultaneously etched.

Further, if the vapor deposition angle θ of the Al film as the mask material is reduced in order to form a finer pattern, another shaded portion that is not covered with the Al film as the mask material also occurs, which is a problem. .

The present invention eliminates the above-mentioned problems and forms a fine pattern with good reproducibility by depositing a mask material a plurality of times at different angles so as to eliminate the other shadowed portions in the step of depositing the mask material. It is an object of the present invention to provide a method for forming a fine pattern capable of achieving the above.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention provides a material for forming a slit-shaped fine pattern on a substrate in a method for forming a fine slit-shaped pattern in the production of a semiconductor device. A step of forming a layer, a step of forming a resist layer on the substance layer, a step of forming an inverse taper-shaped slit in the resist layer and selectively exposing the substance layer, and a step of vertically exposing the substrate. A step of vacuum-depositing a plurality of mask materials so as to cover the entire surface of the material layer except for a shadow portion which is set at a plurality of inclined angles; and the material layer using the plurality of mask materials as a mask. And a step of forming a fine pattern by dry etching.

(Operation) According to the present invention, as described above, even if a shadow portion appears in a portion other than a predetermined portion in order to form a fine pattern, a plurality of mask materials are vacuum-deposited at different angles. That portion can be completely covered with a mask material, and a desired highly precise fine pattern can be formed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a fine pattern forming process showing an embodiment of the present invention.

First, as shown in FIG. 1 (a), an ODUR resist (made by Tokyo Ohka) 12 is applied on a semi-insulating gallium arsenide substrate as a substrate 11 to a thickness of 4000 Å, and then an LMR resist (made by Fuji Chemical). Apply 13 to a thickness of 4000Å. Then, by deep UV contact exposure, the reverse taper-shaped slit 14 having a width dimension of the opening of the upper end of 0.5 μm is patterned. The angle (ω) of the angle of the inversely tapered LMR resist is about 60 °.

Next, as shown in FIG. 1 (b), as a mask material,
The Al film 15 is vapor-deposited by an electron beam vapor deposition method from an oblique direction at an angle θ ₁ (20 °) with respect to the vertical direction to a thickness of 3000 Å. As a result, the shadow portion 16 of the Al film 15 appears, and another shadow portion 17 appears at the corner opposite to the shadow portion 16.

Next, as shown in FIG. 1 (c), as a mask material,
The Al film 18 is also vapor-deposited by an electron beam vapor deposition method to a thickness of 300 Å from an oblique direction at an angle θ ₂ (70 °) with respect to the vertical direction. As a result, the Al film 18 is also vapor-deposited on the shadow portion 17 of the Al film 15.

Then, as shown in FIG. 1 (d), the LMR resist 13
Using the Al films 15 and 18 as a mask material obtained by obliquely depositing the ODUR resist 12 at the edge of the pattern of RIE (Re
O ₂ dry etching by active ion etching is performed vertically under conditions of high anisotropy.

Through the above steps, the slit 19 having a width dimension of about 0.15 μm can be formed.

In this embodiment, in particular, the LMR resist 13 is formed with an inversely tapered slit 14, and the first mask material 15 and the second mask material 15 are formed.
The mask material 18 of is made of Al film, and the LMR resist 1
It is possible to form a highly precise fine pattern by the sharp edge of the inverse taper shape of 3.

Incidentally, instead of the ODUR resist 12 in the above embodiment,
An insulating film such as a SiO ₂ film is used, and the first mask material 15
Instead of the Al film as the second mask material 18, nickel, titanium, or a combination thereof may be used.

FIG. 3 is a sectional view of a fine pattern forming process showing another embodiment of the present invention.

First, as shown in FIG. 3A, an ODUR resist 12 is applied on a semi-insulating gallium arsenide substrate as a substrate 11, and then an LMR resist 13 is applied. Then, by deep UV contact exposure, the slit 14 having an inversely tapered opening at the upper end is patterned. This step is similar to the step shown in FIG.

Next, as shown in FIG. 3 (b), as a mask material,
The Al film 20 is vapor-deposited by an electron beam vapor deposition method from an oblique direction at an angle θ ₃ with respect to the vertical direction. As a result, the surface of the ODUR resist 12 is covered with the Al film 20 so that no shadow portion is formed on the side opposite to the side where the fine pattern is to be formed, and the side where the fine pattern is to be formed is considerably wide. Form a shaded portion 21.

Next, as shown in FIG. 3 (c), as a mask material,
The Al film 22 is also vapor-deposited by an electron beam vapor deposition method from an oblique direction at an angle θ ₄ with respect to the vertical direction. As a result, a shadow portion 23 of a predetermined width is formed on the side where the fine pattern is to be formed.
And the other portions are covered with Al films 20 and 22.

Then, as shown in FIG. 3D, the LMR resist 13
Using the Al films 20 and 22 as a mask material in which the ODUR resist 12 at the edge portion of the pattern is obliquely vapor-deposited as a mask, O ₂ dry etching by RIE is performed to perform vertical etching under conditions of high anisotropy.

The fine slits 24 can be formed by the above steps.

FIG. 4 is a process sectional view of a main part of a fine pattern showing still another embodiment of the present invention.

As shown in FIG. 4A, when the angle (ω ₀ ) of the LMR resist 13 is considerably small, first,
In order to set a shaded portion 30 required to form a predetermined fine pattern, an Al film 31 as a mask material is vapor-deposited by an electron beam vapor deposition method from an oblique direction at an angle θ ₅ with respect to the vertical direction. .

Next, as shown in FIG. 4 (b), in order to cover the corner portion on the side opposite to the side on which the fine pattern is formed, the Al film 32 as a mask material is also vertically formed by the electron beam evaporation method. On the other hand, vapor deposition is performed from an oblique direction with an angle θ ₆ . A shadow portion (gap) 33 is still formed by this vapor deposition.

Next, as shown in FIG. 4C, in order to cover this shadow portion (gap) 33, an Al film 34 is vapor-deposited by an electron beam vapor deposition method from an oblique direction at an angle θ ₇ with respect to the vertical direction.

With such a configuration, it is possible to completely cover except a shadow portion necessary for forming a predetermined fine pattern.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the gist of the present invention.
They are not excluded from the scope of the present invention.

(Effects of the Invention) As described in detail above, the present invention has the following effects.

Even if a shadow portion appears in a portion other than the predetermined portion where the fine pattern is to be formed, that portion can be completely covered with the mask material, so that the desired fine pattern with high accuracy can be formed.

[Brief description of the drawings]

1 is a sectional view of a fine pattern forming process showing an embodiment of the present invention, FIG. 2 is a sectional view of a conventional fine pattern forming process, and FIG. 3 is a fine pattern forming process of another embodiment of the present invention. FIG. 4 is a process sectional view showing a fine pattern forming process showing still another embodiment of the present invention. 11 …… Substrate, 12 …… ODUR resist, 13 …… LMR resist, 14,19,24 …… Slit, 15,18,20,22,31,32,34 ……
Al film (mask material), 16,21,23,30 …… Shadow area, 17 …… Other shadow area, 33 …… Shadow area (gap).

Claims (1)

(57) [Claims] 1. A method of forming a fine slit-shaped pattern in the manufacture of a semiconductor device, comprising: (a) forming a material layer on which a slit-shaped fine pattern is to be formed, and (b) the material layer. A step of forming a resist layer thereon, (c) a step of forming an inverse taper-shaped slit in the resist layer to selectively expose the material layer, and (d) a plurality of tilts with respect to a vertical direction with respect to the substrate. A step of vacuum-depositing a plurality of mask materials so as to cover the entire surface of the material layer except for a shadow portion which is set at an angle, and (e) the material layer is formed by using the plurality of mask materials as a mask. Forming a fine pattern by dry etching.