JPS59172236A - Reactive ion etching device - Google Patents

Abstract

PURPOSE:To increase the etching rate of an Si series material without increasing electric power to be fed from an electric power source by a method wherein a ring manufactured of polytetrafluoroethylene is provided around an etching material on a base electrode, or a porous plate manufactured of polytetrafluoroethylene is provided between the base electrode and a counter electrode. CONSTITUTION:A vacuum vessel 8, a vacuum exhaust vent 9, a treating gas supply piping 10, a base electrode 11, a counter electrode 12, a high-frequency electric power source 13 are provided, and as a porous plate 15 manufactured of polytetrafluoroethylene, a plate having holes of 8mm. diameter, the 10mm. hole pitch, 3mm. thickness is used. The material of struts 16 to support the porous plate 15 is an insulator of alumina. The struts are so set as to make the interval between the porous plate 15 and an etching material 14 (the top surface of a wafer) to be 10mm.. As a ring 17 manufactured of polytetrafluoroethylene, a ring having 101mm. of the internal diameter, 152mm. of the external diameter, 3mm. of thickness is used.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reactive ion etching apparatus used in the manufacturing process of electronic parts such as semiconductors.

Structure of the conventional example and its problems The conventional reactive ion etching apparatus for Si-based materials is
As shown in the figure, a vacuum exhaust connection port 2 is connected to a vacuum exhaust means (not shown) to the vacuum container 1. Processing gas supply piping 3. A substrate electrode 4 and a counter electrode 5 were provided, a high frequency power source 6 was connected to the substrate electrode 4, and a fluorine compound (CF4, 03F8, etc.) was used as a processing gas. 7 is the object to be etched. However, in the above-mentioned reactive ion etching apparatus for Si-based materials, in order to increase the etching rate of Sj-based materials, it is necessary to increase the power from the power supply. This has the disadvantage that the etching rate selectivity (etching rate of Si-based material/etching rate of resist material) with respect to the resist material forming the pattern decreases, making it impossible to carry out reactive ion etching in accordance with the mask pattern.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention provides a reactive ion etching apparatus for Si-based materials that increases the etching rate of Si-based materials without increasing the power from the power supply.

Structure of the Invention The present invention is basically a conventional reactive ion etching apparatus for Si-based materials, by providing a ring made of polytetrafluoroethylene around the object to be etched on a substrate electrode, or by adding a polytetrafluoroethylene ring around the object to be etched on a substrate electrode. By providing a porous plate made of polytetrafluoroethylene between the counter electrode and the counter electrode, when the discharge of the fluorine compound processing gas (CF4, 03F8, etc.) starts, the material that contributes to etching from the processing gas (fluorine and fluorine Since substances that contribute to etching are generated not only from compound ions or radicals, but also from the polytetrafluoroethylene ring and porous plate, the selectivity ratio of etching rate to resist is reduced as in the conventional example. Zuni, Si
It has the unique effect of increasing the etching rate of the system material.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 shows a schematic diagram of a reactive ion etching apparatus for Si-based materials in an embodiment of the present invention.

In Fig. 2, 8 is a vacuum container, 9 is a vacuum exhaust port, and 10 is a vacuum container.
11 is a processing gas supply pipe, 11 is a substrate electrode, 12 is a counter electrode, 13 is a high frequency power source, and 14 is an object to be etched. 1
Reference numeral 5 denotes a porous plate made of polytetrafluoroethylene, and in this example, one with a hole diameter of 8 mm, a hole pitch of 10 mb, and a thickness of 3 mm was used. Reference numeral 16 denotes a column for supporting the perforated plate, and the material is an insulator made of alumina. In this embodiment, 017 is a ring made of polytetrafluoroethylene, and the support is set so that the distance between the perforated plate and the object to be etched (the upper surface of the wafer) is 10 mm. In this embodiment, the ring 17 used had an inner diameter of 101 m, an outer diameter of 152 m, and a thickness of 3 mm. Using the apparatus configured as described above, reactive ion etching of the Si-based material of the present invention was carried out under the etching conditions shown below.

Processing scum 203F8 (perfluoropropane) gas flow rate:
tsoSCCM Vacuum level 20, 08 Torr Power supply 200-300W Object to be etched: Si wafer top 5i with an outer diameter of 100 mm
02 film (6,0008) Figure 3 shows the etching rate of the Sio2 film in this example and the selectivity ratio of the etching rate to the resist;
The results are compared with the results obtained when reactive ion etching was performed under the same etching conditions using the conventional apparatus shown in FIG. 1, where A shows the case of this embodiment and B shows the case of the conventional example. According to this embodiment, as is clear from FIG. 3, a ring made of polytetrafluoroethylene is provided around the object to be etched, and a porous plate made of polytetrafluoroethylene is placed between the counter electrode and the substrate electrode. By providing this, the etching rate of the Sio2 film can be increased without decreasing the selectivity of the etching rate to the resist. This is because, in addition to substances such as ions or radicals of fluorine and fluorine compounds that contribute to the etching of polytetrafluoroethylene, substances that contribute to etching are also generated from polytetrafluoroethylene.

In this embodiment, as shown in FIG. 2, both the porous plate 15 made of polytetrafluoroethylene and the ring 17 made of polytetrafluoroethylene were provided, but it is also possible to install only one of them. I can't say enough good things about it. Furthermore, in this example, the object to be etched was the 8102 film, but the object to be etched may be any of a single crystal, polycrystalline St film, and nitride St film. In reactive ion etching of system materials, a ring made of polytetrafluoroethylene is placed around the object to be etched, or a porous plate made of polytetrafluoroethylene is placed between the counter electrode and the substrate electrode. The etching rate of Si-based materials can be increased without decreasing the etching rate selectivity, and the effect is significant.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional reactive ion etching device for Si-based materials, FIG. 2 is a schematic diagram of a reactive ion etching device for Si-based materials according to an embodiment of the present invention, and FIG. 3 is a schematic diagram of a reactive ion etching device for Si-based materials according to an embodiment of the present invention. High frequency power and Sio in one embodiment and conventional example
FIG. 3 is a diagram comparing the relationship between the etching rates of the two films and the relationship between high frequency power and etching rate selectivity. -I- 8... Vacuum container, 9... Vacuum exhaust connection port, 10... Processing gas supply piping, 11...
...Substrate electrode, 12...Counter electrode, 13...
...High frequency power supply, 14...Object to be etched,
15...7... Ring made of polytetrafluoroethylene, 1
7...Porous plate made of polytetrafluoroethylene. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (3)

[Claims] (1) A vacuum container, a vacuum evacuation means connected to the vacuum container, a processing gas supply means, a substrate electrode provided in the vacuum container for placing an object to be etched, and the A counter electrode provided opposite to the substrate electrode, a high frequency power source electrically connected to either one of the electrodes in the vacuum container, and a polytetrafluoride provided in a plasma generation region in the vacuum container. A reactive ion etching device consisting of ethylene members. (2) The reactive ion etching apparatus according to claim 1, wherein the member made of polytetrafluoroethylene is a ring provided around the object to be etched on the substrate electrode. (3) The reactive ion etching apparatus according to claim 1, wherein a porous plate is provided between the substrate electrode and the counter electrode as the polytetrafluoroethylene member.