JPH0733568B2 - Thin film formation method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for application in manufacturing a semiconductor circuit device having a thin film such as an insulating film having a required pattern on a semiconductor substrate. Regarding the forming method.

2. Description of the Related Art Conventionally, as a thin film forming method, a method described below with reference to FIG. 2 has been proposed.

That is, a mask layer 3 made of photoresist, for example, is formed on a main surface 2 of a substrate 1 on which a thin film such as an insulating film having a desired pattern is to be formed on the main surface of a semiconductor substrate, for example. It is formed (Fig. 2A).

Next, by using the mask layer 3 as a mask on the main surface 2 of the substrate 1, a sputtering deposition process is performed from above the substrate 1 to form a material such as SiO ₂ on the main surface 2 of the substrate 1. The thin film 4 is formed to have a smaller thickness than the mask layer 3 (FIG. 2B). In this case, at the same time when the thin film 4 is formed, a layer 6 made of the same material as the thin film 4 is additionally formed on the side surface of the mask layer 3, and a layer made of the same material as the thin film 4 is also formed on the upper surface of the mask layer 3. 5 is formed.

Next, the layer 6 deposited on the side surface of the mask layer 3 is formed.
Is more fragile than the thin film 4 formed on the main surface 2 of the substrate 1 and the layer 5 formed on the upper surface of the mask layer 3, so that the required etchant was used. When the etching process is performed, the layer 6 is etched at a higher speed than the thin films 4 and 5, and thus the layer 6 is masked by the etching process using a required etchant. From the side surface (Fig. 2C).

Next, the thin film 4 and the layer 5 cannot be removed, or even if they can be removed, the solvent is harder to remove than the mask layer 3 (the mask layer 3 is a photoresist, and the thin film 4 and the layer 5 are SiO _2).
In the case of 1), the mask layer 3 is removed from the substrate 1 together with the layer 5 formed thereon by dissolving away the mask layer 3 using an organic solvent (FIG. 2D).

As described above, the thin film 4 having the required pattern inverted from the mask layer 3 is formed on the substrate 1.

The above is the conventionally proposed thin film forming method.

Problems to be Solved by the Invention However, in the case of the above-described conventional thin film forming method, the sputtering deposition process performed in the step of forming the thin film 4 by the sputtering deposition method becomes the thin film 4 disposed above the substrate 1. Performed with a target of material, and the target has an area, and
Since there is a limit to making the distance between the target and the substrate 1 sufficiently large, the vicinity of the mask layer 3 side of the substrate 1 is shaded when viewed from the side of the target. 2, the mask layer 3 side is gradually thinned toward the mask layer 3 side, so that the thin film 4 has a desired thickness over the entire area. It had the inconvenience that it was not formed.

By the means for solving the problem, the present invention proposes a novel thin film forming method capable of effectively avoiding the above-mentioned inconvenience.

The thin film forming method according to the present invention has a step of forming a mask layer on a substrate as in the case of the conventional thin film forming method described above with reference to FIG. After that, on the substrate, using the mask layer as a mask, from above the substrate, the sputtering deposition process and the sputtering etching process are sequentially and alternately repeated, or by performing a process performed simultaneously,
A step of forming a thin film on the substrate so as to have a smaller thickness than that of the mask layer is performed, and thereafter, the thin film is formed on the substrate in the same manner as in the conventional thin film forming method described above with reference to FIG. In the step of removing the layer of the same material as the thin film adhered and formed on the side surface of the mask layer in the step of forming, and the mask layer is formed by melting the mask layer to form the thin film on the substrate. With the layer of the same material as the thin film formed on the upper surface of the mask layer in the step of
The target thin film is obtained by the step of removing from the substrate.

According to such a thin film forming method of the present invention, since the sputtering etching process is performed in the step of forming the thin film on the substrate, the sputtering deposition process is performed in the step of forming the same thin film. Etches a layer of the same material as the thin film deposited on the upper edge region of the mask layer, and the same material as the thin film protruding from the mask layer by the etching is mainly near the mask layer side of the thin film. Reattach to.
Therefore, the thin film is formed in the region on the mask layer side to have substantially the same thickness as the other regions.

EFFECTS OF THE INVENTION Therefore, according to the thin film forming method of the present invention, there is an effect that the target thin film can be formed to have a uniform thickness in each portion.

Example 1 FIG. 1 shows a first example of a thin film forming method according to the present invention, and a thin film is formed by the following sequential steps.

That is, although not shown, similar to the case of the conventional thin film forming method described above with reference to FIG. 2, on the main surface 2 of the substrate 1 similar to that described above with reference to FIG. Mask layer 3
To form.

Next, as in the case of the conventional thin film forming method described above with reference to FIG. 2, the mask layer 3 is used as a mask on the substrate 1 to perform the sputtering deposition process from above the substrate 1 to thereby form the substrate 1 On the main surface of the thin film 4a ′ made of, for example, SiO _2.
Is formed to be thinner than the mask layer 3 (FIG. 1A). In this case, at the same time when the thin film 4a 'is formed, the layer 6a' of the same material as the thin film 4a 'is formed on the side surface of the mask layer 3 and the layer of the same material is also formed on the upper surface of the mask layer 3.
5a 'is formed.

Next, a sputtering etching process is performed from above the substrate 1. Since then, the sputter etching process is carried out with a dependence on the surface topography of the layers to be etched thereby, mainly layers 5a ′ and 6a.
Area 7 attached to the upper edge area of the mask layer 3 of a '
a'is etched, and the thin film 4a 'and the layers 5a' and 6a 'which are etched out and protrude from the mask layer 3 are etched.
The same material as in (1) is reattached mainly to the vicinity of the mask layer 3 side of the thin film 4a ', and the thin film 4a' is attached to the mask layer 3 side of the thin film 4a '.
A layer 4b 'of the same material as the
A thin film 4'comprising b'is formed (FIG. 1B).

Next, the same steps as those for forming the thin film 4a 'are taken again, and a thin film 4a "similar to the above-mentioned thin film 4a' is formed on the thin film 4 '.
Are formed (FIG. 1C). In this case, a similar layer 6a ″ is formed on the layer 6a ′ described above, and the layer 5a
A similar layer 5a ″ is also formed on a ′.

Next, by performing the same sputtering etching process as when forming the layer 4b ′ described above, a layer 4b ″ similar to the layer 4b ′ described above is formed in the vicinity of the mask layer 3 side of the layer 4a ″. Therefore, the thin film 4 consisting of the thin film 4 ′ and the layers 4a ″ and 4b ″ is formed on the substrate 1, and the layers 5a ′ and
A layer 5 of 5a ″ is formed on the upper surface of the mask layer 3 and a layer 6 of layers 6a ′ and 6a ″ is formed on the side surface of the mask layer 3 (FIG. 1D).

Then, in the same manner as described above with reference to FIG. 2, the layer 6 is formed by performing an etching process using a required etchant.
It is removed from the side surface on the mask layer 3 side (FIG. 1E).

Next, as in the case described above with reference to FIG. 2, the mask layer 3 is removed from the substrate 1 together with the layer 5 formed thereon by dissolving away the mask layer 3 using a solvent. (Fig. 1F).

As described above, the thin film 4 having the required pattern inverted from the mask layer 3 is formed on the substrate 1.

The above is the first embodiment of the thin film forming method according to the present invention.

According to such a first embodiment of the present invention, the above-mentioned layer 4 is formed by the above-mentioned sputtering etching process.
power applied to the substrate 1 when forming b ′ and 4b ″,
It will be apparent that the thickness of the layers 4b 'and 4b "can be controlled by controlling the time for performing the sputter etching process, so that the thin film 4 can be uniformly formed in each part.

Example 2 In the above-described first example of the present invention, the case where the thin film 4 is formed by sequentially and alternately repeating the sputtering deposition process and the sputtering etching process has been described.

However, in the second embodiment according to the present invention, although detailed description is omitted, instead of sequentially performing the sputtering deposition process and the sputtering etching process described above with reference to FIG. According to the present invention described above, the same steps as those of the thin film forming method according to the present invention described above with reference to FIG. 1 are performed, except that the sputtering deposition process and the sputtering etching process are simultaneously performed by the method. The target thin film 4 is formed in the same manner as in the first embodiment.

By controlling the electric power applied to the substrate 1 when the sputtering deposition process and the sputtering etching process are simultaneously performed by the thin film forming method according to the present invention as well, the target thin film 4 is formed to have a uniform thickness in each part. It will be clear that it can be formed into

Note that, in the above, only two examples of the present invention are shown, and when the above-described sputtering deposition treatment and sputtering etching treatment are sequentially performed, these are repeated to form a target thin film. You can also do it. In this case, if the number of repetitions is increased, but the thin film is formed as thin as possible when performing each sputtering deposition process, the target thin film is almost the same as the other parts up to the vicinity of the mask layer. The thickness of the target thin film 4 can be increased, and since the layer formed on the side surface of the mask layer 3 in each sputtering deposition process is formed to be thin, the target thin film 4 can be formed on the side surface (mask (Formed by being regulated by the layer 3) can have an inclined surface with few steps.

Besides, various modifications and changes may be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic sectional view in a sequential process showing a thin film forming method according to the present invention. FIG. 2 is a schematic cross-sectional view in sequential steps showing a conventional thin film forming method. 1 ... Substrate 2 ... Main surface 3 ... Mask layer 4,4 ', 4a', 4a "... Thin film 4b, 4b" ... Layer 5,5a ', 5a "... Layer 6,6a', 6a "……layer

Claims (1)

[Claims] 1. A process of forming a mask layer in a desired pattern on a substrate, and a sputtering deposition process and a sputtering etching process from above the substrate using the mask layer as a mask on the substrate. By performing processing that is repeated alternately in sequence, or performed simultaneously,
The same as the thin film deposited on the side surface of the mask layer in the step of forming a thin film on the substrate to a thickness smaller than that of the mask layer and the step of forming the thin film on the substrate. The step of removing the layer of material and the step of forming the thin film on the substrate by melting away the mask layer are the same as the thin film formed on the upper surface of the mask layer. A method of forming a thin film, which comprises a step of removing from the substrate together with a layer of material.