JPH01128421A - Glass substrate for semiconductor element and manufacture thereof - Google Patents

Abstract

PURPOSE:To make a semiconductor film having excellent characteristics grow graphoepitaxy at the surface of a substrate, by dry-etching selectively a thin film after forming the thin film that is affected by etching with greater ease than a glass plate having a uniform thickness at the surface of a glass plate having a flat surface. CONSTITUTION:Rectangular grooves 2 at a semiconductor element glass substrate where a plurality of the rectangular grooves are arranged at the surface of the substrate are composed of side walls that are formed by sectional faces of a thin film which is affected by etching with greater ease than a glass plate that is provided at base walls that are formed by the surface of the glass plate as well as at the surface of the glass plate. Such glass substrate is formed by the following processes. A nitriding silicon film 4 having 100nm thickness uniformly is formed with a plasma, process at the surface of the glass plate 1 and a photoresist film 5 is provided on the nitriding silicon film 4 and then a mask material is obtained by performing the treatment of exposure and development. After that, the glass plate with the mask material is etched by dry-etching process where a CH2 F2d gas is used. Then, the glass plate with the mask material is taken out in a state that its mask material is etched and after that the mask material is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a glass substrate for a semiconductor element on which a semiconductor film is coated to form a semiconductor device, and a method for manufacturing the same. The present invention relates to a glass substrate for semiconductor devices on which a film can be formed and a method for manufacturing the same.

[Prior Art] As a method for forming a semiconductor film with a single crystal plane on a glass substrate, a graphoepitaxy method using a groove shape formed on a glass substrate has been known. FIG. 2 shows a conventional glass substrate used in the graphoepitaxy method. The glass substrate has a rectangular groove 2 formed on the main surface of the glass substrate 1 using a dry etching method or the like, and when the groove 2 is rectangular in shape,
It is known that a (100)-plane semiconductor film grows graphoepitaxially in the vertical direction using the corner 3 of the trench 2 as a crystal nucleus. (For example, Appl.

Phys, Lett, LL-71 (1979) [Problems to be Solved by the Invention] In the above-mentioned grapho-epitaxial growth, the directionality of the growing crystal is influenced by the directionality of the corner 3 and exhibits good characteristics. In order to grow a semiconductor film, the corner 3
needed to form accurate rectangular corners.

However, in the conventional glass substrate for semiconductor elements, the groove 2 is a U-shaped groove due to the method of forming the groove (dry etching 11). However, it has not been possible to grow a semiconductor film having a single crystal plane. This has been a problem in producing high-speed operating semiconductor devices.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and is directed to a glass substrate for semiconductor devices in which a large number of rectangular grooves are provided on the surface of the glass substrate. The mold groove is constituted by a bottom wall formed by the glass plate surface and a side wall formed by a cross section of a thin film that is more easily etched than the glass plate provided on the glass plate surface.

The glass substrate for semiconductor devices can be produced, for example, by a method in which a thin film that is more easily etched than a glass plate with a uniform thickness is formed on the surface of a glass plate with a flat surface, and then the thin film is selectively dry-etched. can.

The thickness of the thin film is preferably 3 nm to 1 μm.
If it is thinner than 3 nm, the depth of the groove formed by the thickness of the thin film becomes too shallow, making it ineffective for graphite epitaxial growth, and if it is thicker than 1 .mu.m, productivity tends to decrease.

The thin film needs to be a thin film that is more easily etched than a glass plate, but the effect of the present invention will not be achieved if the thin film is etched more easily than a glass plate.

The thin film that is more easily etched than the glass plate is
For example, a thin film such as a silicon nitride film formed by a plasma method, in which the bonding strength between elements within the thin film is relatively weak, is used.

The grooves formed in the glass substrate for semiconductor devices have a width of 0.5 mm, similar to conventional grooves, from the viewpoint of grapho-epitaxial growth.
0.01-1μ field, 3nm-1μm deep groove
It is preferable to provide them at intervals of m.

[Example] A silicon nitride film 4 having a thickness of 1100 nm was uniformly formed on the surface of a glass plate 1 by a plasma method.

Thereafter, a photoresist film 5 (not shown) is provided on the silicon nitride film 4, and a mask material 6 (not shown) is formed by exposure and development.
And so. After that, read the glass plate with 6 masking materials CH2F2
Dry etching method using ff gas (gas pressure 0.05
Tor r r% RF power density 0, IOW/cffF)
I etched it with After etching for about 3 minutes, the glass plate with the mask material 6 was taken out and the mask material 6 was removed.

The etching speed under the above etching conditions is about 30 nm/min and about 1.5 nm/min for the silicon nitride film and the glass plate, respectively, and the etching speed of the glass plate is about 1/20 of the etching speed of the silicon nitride film, Therefore, the surface of the glass plate 1 was exposed as the bottom surface of the groove 2 formed by etching, and the side surface of the silicon nitride film was exposed as the side surface of the groove 2, so that an approximately accurate rectangular groove was formed.

Note that the above etching uses CH2F2 instead of CH2F2.
This can also be done using F3, but to form a rectangular groove, C
H2F2 is preferred.

The groove-shaped cane of the glass substrate for semiconductor devices produced in this example has almost exact rectangular grooves as shown in FIG. Roundness or fine grooves called sub-trenches, which are seen in the grooves of glass substrates, were not formed.

Using the glass substrate for a semiconductor element prepared according to this example, a semiconductor film was grown on the surface of the substrate by grapho-epitaxial growth. The semiconductor film had a good crystal plane and was a film with good characteristics.

[Effects of the Invention] According to the present invention, since the rectangular shape of the groove formed on the substrate surface is accurate, a semiconductor film having good characteristics can be grown on the surface by graphite epitaxial growth. Further, according to the manufacturing method of the present invention, it is possible to easily manufacture a glass substrate for a semiconductor element having an accurate rectangular shape.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing a glass substrate for semiconductor devices produced in accordance with an example, and FIG. 2 is a cross-sectional view schematically showing a conventional glass substrate for semiconductor devices.

Claims (3)

[Claims] (1) In a glass substrate for semiconductor devices in which a large number of rectangular grooves are provided on the glass substrate surface, the rectangular grooves are etched more than the bottom wall formed by the glass plate surface and the glass plate provided on the glass plate surface. A glass substrate for a semiconductor device, characterized in that the sidewall is formed by a cross section of a thin film that is easily damaged. (2) The glass substrate for a semiconductor device according to claim 1, wherein the thin film has a thickness of 3 nm to 1 μm. (3) In a method for manufacturing a glass substrate for semiconductor devices having a large number of rectangular grooves on the surface, a thin film that is more easily etched than a glass plate with a uniform thickness is created on the surface of a glass plate with a flat surface, and then the thin film is A method for manufacturing a glass substrate for semiconductor devices, characterized by selective dry etching.