JPH07161690A - Method for etching silicon carbide body - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for etching a silicon carbide body capable of etching the silicon carbide body at a high etching rate without generating particles that hinder fine processing. A silicon carbide body is arranged on an electrode in a vacuum chamber, a mixed gas of a fluorine-based gas and oxygen is supplied into the chamber, and plasma is generated between the electrode and a counter electrode to form the silicon carbide body. In the method for performing reactive ion etching, the silicon carbide body is placed on the electrode in a state of being placed on a plate made of quartz glass or silicon having a size similar to the area of the electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a silicon carbide body, and more particularly to reactive ion etching (R
It relates to a method of etching a silicon carbide body by the IE) method.

[0002]

2. Description of the Related Art As one of uses of a silicon carbide body, application to a blue light emitting diode, for example, is considered. The blue light emitting diode has a structure in which electrodes are formed on a p-type layer and an n-type layer of silicon carbide having a pn junction, respectively. The blue light emitting diode has a p-type due to dicing.
In order to avoid introducing defects into the n-junction, the RIE method is used to selectively etch the pn-junction in advance, and then,
A method of dicing to separate each element is adopted.

By the way, as a method of etching the above-mentioned silicon carbide body, a silicon carbide body is conventionally arranged on an electrode made of Al or the like in a vacuum chamber, and a fluorine-based gas (for example, SF ₆ ) and oxygen are mixed in the chamber. A method of reactively etching the silicon carbide body by supplying a gas and applying high-frequency power to the electrode to generate plasma between opposed electrodes (for example, a chamber container) is used. However, the silicon carbide body is small, for example, 2 cm, and a large diameter wafer such as a silicon wafer used for manufacturing a semiconductor device cannot be manufactured. Therefore, when it is arranged on the electrode, a considerable area of the electrode is exposed. As a result, an electrode material (for example, A
There is a problem in that l) is sputtered and adheres to the etching surface of the silicon carbide body to cause a micromask phenomenon, which hinders the progress of etching.

For this reason, electrodes made of graphite have been used. When an electrode made of such a material is used, the substance to be sputtered is carbon, which is a constituent element of the silicon carbide body, so that the above-mentioned micromask phenomenon can be avoided, but it is fragile and becomes an obstacle to fine processing. Particles are generated.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for etching a silicon carbide body capable of etching a silicon carbide body at a high etching rate without producing particles that hinder fine processing. To do.

[0006]

In the method for etching a silicon carbide body according to the present invention, a silicon carbide body is arranged on an electrode in a vacuum chamber, and a mixed gas of a fluorine-based gas and oxygen is supplied into the chamber. In the method of performing reactive ion etching on the silicon carbide body by generating plasma between the electrode and the counter electrode, a dish made of quartz glass or silicon having a size similar to the area of the silicon carbide body. It is characterized in that it is placed on the electrode in a state of being placed on the electrode.

Examples of the fluorine-based gas include SF ₆ and C
F ₄ , NF _3, etc. can be used. The electrodes are made of, for example, Al. The electrodes are connected to a high frequency power source and a high frequency of 13.56 MHz is applied.

As the counter electrode, an electrode separately arranged in a vacuum chamber may be used, or a container of the chamber may be used as an electrode. The etching method according to the present invention allows magnetron etching to be performed by providing a magnet close to the outside of the vacuum chamber.

[0009]

According to the present invention, a silicon carbide body is placed on an electrode in a vacuum chamber in a state of being placed on a plate made of quartz glass or silicon having a size similar to the area of the electrode, and fluorine is placed in the chamber. By supplying a mixed gas of a system gas and oxygen to generate plasma between the electrode and the counter electrode, the electrode having a larger area than that of the silicon carbide can be covered with the dish. Sputtering of (for example, Al) can be prevented. As a result, the micromask phenomenon that accompanies the sputtering of the electrode material can be avoided. During the etching, the quartz glass or silicon dish is also sputtered, but its component is Si, which is one component of the silicon carbide body,
Since it can be removed with an etchant of a silicon carbide body, the micromask phenomenon can be avoided. Therefore, the silicon carbide body can be etched at a high rate. Further, since quartz glass or silicon has sufficiently high strength, it is possible to prevent the generation of particles which hinders fine processing. Furthermore, the etching surface can be smoothed by avoiding the micromask phenomenon.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a magnetron etching apparatus used in Examples 1 and 2 of the present invention. A vacuum chamber 2 is formed in a reaction container 1 made of a conductive material that also serves as a counter electrode. The reaction vessel 1 is grounded. The electrode 3 made of, for example, Al is arranged in the chamber 1. The high frequency power source 4 is the electrode 3
To the blocking capacitor 5 via.
An O ₂ gas supply pipe 6 is connected to the reaction vessel 1, and a mass flow controller 7 and a valve 8 are sequentially provided in the supply pipe 6 from the O ₂ gas supply source side. SF
_{A 6} gas supply pipe 9 is connected to the reaction vessel 1, and a mass flow controller 10 and a valve 11 are sequentially provided in the supply pipe 9 from the SF ₆ gas supply source side.
The exhaust pipe 12 is connected to the reaction container 1, and the exhaust pipe 12 is provided with a turbo molecular pump 13 and a dry pump 14 in this order from the reaction container 1 side. The Macnet 15 is arranged above the vessel 1 so that its N and S poles face the upper surface of the reaction vessel 1, and is rotated by a rotating shaft 16 in a clockwise direction, for example.

Example 1 First, a silicon carbide substrate 17 was placed on the electrode 3 of the chamber 2 in a state of being placed on a quartz glass dish 18 having substantially the same area as the electrode 3. Subsequently, the turbo molecular pump 13 and the dry pump 14 were operated to evacuate the gas in the chamber 2 through the exhaust pipe 12 and maintain the degree of vacuum at 0.05 torr. Subsequently, SF ₆ and O ₂ gas are supplied to the supply pipes 6 and 9
To the chamber 2 through SF ₆ ; 30 sccm, O
₂ ; 70 sccm, SF ₆ ; 65 sccm, O ₂ ; 35
sccm, and SF ₆ ; 90 sccm, O ₂ ; 10 s
Supply so as to be ccm, and high frequency power source 4 to 13.5
High-frequency power of 6 MHz and 300 W is applied to the electrode 3 through the blocking capacitor 5, and at the same time, the magnet 15 is rotated by the rotating shaft 16 at a speed of 500 rpm to generate plasma in the chamber 2 between the electrode 3 and the reaction vessel 1. Then, the silicon carbide substrate 17 was etched by the generated ions and radicals.

The etching rate of the silicon carbide substrate was measured when a mixed gas of the above three kinds of SF ₆ and O ₂ gas was used. The result is shown in FIG. As is clear from FIG. 2, the silicon carbide substrate 17 is formed on the electrode 3 of the chamber 2.
It can be understood that the etching can be performed at a high rate by arranging the electrodes on the quartz glass plate 18 having the same area as that of the electrode 3 in a state of being placed.

Further, the silicon carbide substrate 1 after the etching
Observation of the etched surface of No. 7 revealed that it was extremely smooth. Example 2 Example 2 is an example applied to the manufacture of a blue light emitting diode element.

First, as shown in FIG. 3 (a), an n-type crystalline silicon carbide body doped with phosphorus is produced by a pulling method, and an n-type crystalline silicon carbide substrate 21 is cut out therefrom, and then the substrate is formed. A p-type crystalline silicon carbide layer 22 doped with boron was formed on the surface 21 by an epitaxial growth method. Subsequently, an Au film was sputter-deposited on the surface of the silicon carbide layer 22 and patterned to form a plurality of Au electrodes 23 also serving as an etching mask.

Then, the silicon carbide substrate 21 was placed on the electrode 3 of the vacuum chamber 2 of the magnetron etching apparatus shown in FIG. 1 in the state of being placed on the quartz glass dish 18 as in the first embodiment. Then, in the same manner as in Example 1, the turbo molecular pump 13 and the dry pump 14 are operated to evacuate the gas in the chamber 2 and maintain the degree of vacuum at 0.05 torr, and supply SF ₆ and O ₂ gas to the supply pipe 6, SF ₆ ; 65 sccm, O ₂ ; 35 sc into the chamber 2 through 9
It is supplied so that it becomes cm, and the high frequency power source 4 to 13.56
High frequency power of 300 W at MHz is applied to the electrode 3 through the blocking capacitor 5, and at the same time the magnet 1
5 was rotated at a speed of 500 rpm by the rotating shaft 16 to generate plasma in the chamber 2 between the electrode 3 and the reaction vessel 1. At this time, the portion of the silicon carbide layer 22 exposed from the Au electrode 23 is selectively etched by the ions and radicals generated as shown in FIG. 3B, and the silicon carbide layer 22 and the silicon carbide substrate are further etched. The surface layer of the silicon carbide substrate 21 was etched across 21 pn junctions.

Next, the substrate 21 after etching is taken out from the vacuum chamber 2, and is diced at the substrate 21 at the bottom of the etching section 24 shown in FIG. 3B, and the Au electrode is formed on the back surface of the substrate 21 after dicing. By forming 25, the blue light emitting diode element 26 shown in FIG. In the dicing step, since the etching surface of the silicon carbide substrate 21 at the bottom of the etching portion 24 was extremely smooth, dicing could be performed smoothly.

The obtained blue light emitting diode element 26 is
pn of p-type silicon carbide substrate 21 and n-type silicon carbide layer 22
It was confirmed that there was no defect in the junction and highly efficient blue light emission was performed.

[0018]

As described in detail above, according to the method for etching a silicon carbide body of the present invention, it is possible to etch the silicon carbide body at a high etching rate without generating particles that hinder fine processing. As a result, remarkable effects such as effective utilization for manufacturing blue light emitting diode elements can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view showing a magnetron etching apparatus used in an embodiment of the present invention.

FIG. 2 SF ₆ in a mixed gas supplied to a vacuum chamber
FIG. 3 is a characteristic diagram showing the relationship between the ratio of C ₂ and O ₂ and the etching rate of a silicon carbide body.

FIG. 3 is a cross-sectional view showing the manufacturing process of the blue light emitting diode element according to the second embodiment of the present invention.

[Explanation of symbols]

1 ... reactor 2 ... vacuum chamber, 3 ... electrode 4 ... high-frequency power source, 6 ... O ₂ supply pipe, 9 ... SF ₆ supply pipe, 12 ... exhaust pipe, 15 ... macro net.

Claims (1)

[Claims] 1. A silicon carbide body is disposed on an electrode in a vacuum chamber, a mixed gas of a fluorine-based gas and oxygen is supplied into the chamber, and plasma is generated between the electrode and a counter electrode to perform the carbonization. In the method of performing reactive ion etching on a silicon body, the silicon carbide body is placed on the electrode while being placed on a plate made of quartz glass or silicon having a size similar to the area of the electrode. Etching method of silicon carbide body.