JPH0573051B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a method for manufacturing semiconductor devices, in which the surface of a workpiece is uniformly etched, side etching is small, and side etching is small.
The present invention also relates to a plasma etching apparatus capable of performing reactive ion etching with high productivity.

[Conventional technology]

FIG. 2 is a sectional view of a main part of a conventional plasma etching apparatus disclosed in, for example, Japanese Patent Application Laid-Open No. 56-67925. In the figure, 11 is an etching chamber;
12 and 13 are electrode plates installed in parallel to each other in the etching chamber 11; 14 is a gas introduction pipe attached to the electrode plate 12 for introducing an etching reaction gas between the electrode plates 12 and 13; and 15 is a gas introduction pipe in the etching chamber 11. A gas exhaust pipe 16 attached thereto for exhausting the gas inside the etching chamber 11 to the outside is a target object to be etched, which is placed on the electrode plate 12. 17
is a high frequency power source connected to both electrodes 12 and 13 for generating plasma of an etching reaction gas.

In order to etch the object to be processed 16 using the plasma etching apparatus configured in this way,
A reactive gas such as CF ₄ or CCl ₄ is introduced into the etching chamber through the gas introduction pipe 14, and is exhausted through the gas exhaust pipe 15 using a vacuum pump to form the etching chamber 11.
Maintain a vacuum level of 10 ^-2 to several Torr inside. Then, a high frequency voltage of 500 V to 1 KV and 13.56 MHz is applied between the electrode plates 12 and 13 to generate plasma by high frequency glow discharge. Then, the active chemical species present in this plasma react with the object to be processed 16 such as silicon or silicon nitride to generate volatile compounds, which are removed by exhaust from the exhaust pipe 15 to the outside of the etching chamber. Etching progresses.

[Problem that the invention seeks to solve]

Since conventional plasma etching equipment is configured as described above, the plasma concentration in the etching chamber is non-uniform within the electrode surface, and plasma may be generated only in areas with high potential, resulting in poor etching reproducibility. There were problems such as poor etching speed and poor uniformity of etching rate.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a plasma etching apparatus and an etching method that can improve the reproducibility of etching and the uniformity of etching rate.

[Means for solving problems]

The plasma etching apparatus according to the present invention includes a counter electrode on which a workpiece is placed, and a rotating magnetic field generating means for generating a rotating magnetic field for confining plasma between the two electrodes and rotating the plasma within the electrode plane. and rotating magnetic field moving means for moving the rotating magnetic field relative to both electrodes. Further, in the etching method according to the present invention, plasma generated by glow discharge between electrode surfaces is confined in a rotating magnetic field and rotated, and is moved within the electrode surface toward the object to be processed. It is designed to be etched.

[Effect]

In this invention, plasma generated by glow discharge between the electrode surfaces is confined by a magnetic field and moves within the electrode surface as the magnetic field rotates, and during this movement it becomes stabilized and the object to be processed is etched in this state. This allows for reproducible and uniform etching.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1A and 1C are sectional views of the main parts of the apparatus during plasma generation, respectively, for explaining a plasma etching apparatus and etching method according to an embodiment of the present invention, and FIG. 1B is a top view of the main parts thereof. It is. In the figure, 1 and 2 are upper and lower electrode plates installed parallel to each other, 3 is a high-frequency power source connected to both electrodes 1 and 2 and used to generate a plasma of reaction gas for etching, 4 is a magnetic field, and 5 6 is a plasma generated by applying high frequency power to the electrodes 1 and 2, and 6 is a plurality of electromagnets arranged in a ring shape so as to be able to move up and down between the electrode plates 1 and 2, which are provided around the plasma 5. This is because only a pair of opposing electromagnets are magnetized to N and S poles, forming a bridge of magnetic field between them, and the magnetized pair of N and S poles electrically move across the ring. It is now possible to move. Reference numeral 7 denotes a target object placed on the lower electrode plate 2 and to be etched.
Further, 8 is an etching chamber.

Next, an etching method using this apparatus will be explained.

As shown in figure a, upper and lower electrodes 1 and 2
When high-frequency power is applied by the high-frequency power supply 3 in between, plasma is generated over the entire area between the electrodes. At this time, when a magnetic field 4 is applied to this plasma, the plasma is confined by the magnetic field 4, forming a bridge on the upper electrode surface as shown in FIG. Furthermore, when this bridge of plasma is electrically rotated in the circumferential direction by the ring-shaped electromagnet 6, the plasma spreads over the entire area of the upper electrode surface. Such plasma is generated at a position isolated from the object to be processed 7, as shown in FIG. 1A, and then, as shown in FIG. The plasma 5 is moved by moving down to the point where the object to be processed 7 is exposed to the plasma 5 and etched. At this time, by increasing the strength of the magnetic field generated by the electromagnet, the plasma concentration within the etching chamber 8 becomes constant over the entire area between the electrodes.

As described above, in this embodiment, the plasma is confined in a rotating magnetic field and the plasma is moved from the upper electrode to the lower electrode where the object to be processed is located for etching. This enables reproducible and uniform etching without exposing the etching. Furthermore, by adjusting the rotational speed of the magnetic field and the number of electromagnets, stable intermittent plasma etching is also possible.

In the above embodiment, the ring-shaped electromagnet is moved up and down, but the etching chamber may be moved up and down.

Furthermore, although the ring-shaped electromagnet is provided outside the etching chamber in the above embodiment, it may also be provided inside the etching chamber.

〔Effect of the invention〕

As described above, according to the present invention, the plasma generated between the opposing electrodes is confined in a magnetic field, the magnetic field is rotated, and the plasma is moved vertically within the surface of the opposing electrodes relative to the object to be processed. let me,
Since the object to be processed is etched using the plasma, the plasma is stabilized in the rotating magnetic field, and uniform etching with reproducibility can be achieved.

[Brief explanation of the drawing]

1A and 1C are cross-sectional views of the main parts of the apparatus during plasma generation and etching, respectively, for explaining a plasma etching apparatus and etching method according to an embodiment of the present invention, and FIG. 1B is a top view of the main parts thereof. 2 are cross-sectional views showing a conventional plasma etching apparatus. DESCRIPTION OF SYMBOLS 1... Upper electrode, 2... Lower electrode, 3... High frequency power supply, 4... Magnetic field, 5... Plasma, 6... A pair of electromagnets arranged in a ring shape (rotating magnetic field generating means), 7... Object to be processed.

Claims (1)

[Scope of Claims] 1. An upper electrode and a lower electrode, an object to be processed placed on the lower electrode, a high frequency power source that generates plasma by applying power between the upper and lower electrodes, and the plasma A rotating magnetic field generating means for generating a rotating magnetic field for rotating the object within the surface of the electrode, and a rotating magnetic field moving means for moving the rotating magnetic field vertically relative to the object to be processed. Characteristic plasma etching equipment. 2. The rotating magnetic field generating means includes a plurality of electromagnets disposed around the plasma and facing each other to form a magnetic field, and the magnetic fields of the plurality of electromagnets sequentially rotate in a circumferential direction to generate the rotating magnetic field. A plasma etching apparatus according to claim 1, characterized in that the plasma etching apparatus generates the following: 3. The plasma etching apparatus according to claim 1 or 2, wherein the rotating magnetic field moving means moves the electromagnet. 4. In a method of etching the object to be processed using plasma generated by glow discharge between opposing electrode surfaces on which the object to be processed is placed, the generated plasma is confined in a magnetic field and rotated, and the An etching method characterized in that the object to be processed is etched by moving the electrode in the direction of the object to be processed.