JPS6173331A - Dry etching device - Google Patents

Abstract

PURPOSE:To equalize the etching speed of a wafer by applying a high frequency voltage that the radical density or ion density of a dry etching reaction gas between the central disc of an upper electrode and a plurality of annular plates and lower electrodes become uniform to therebetween. CONSTITUTION:A vacuum vessel 1 and upper and lower electrodes 2, 3 provided oppositely at an interval in the vessel 1 are provided in a dry etching device. A wafer 50 to be etched is placed on the electrode 3, and dry etching reaction gas is fed from the lower center of the electrode 2 through a gas tube 7. The electrode 2 is composed of a central disc 2a and a plurality of annular plates 2b, 2c concentric with the disc 2a, and an upper electrode leading rod 4a, and annular electrode leading rods 4b, 4c are provided at the discs 2a and 2b, 2c, respectively. High frequency voltages are applied from high frequency power generators 10a-10c, respectively to between the disc 2a, the plates 2b, 2c, and the electrode 3, thereby equalizing the radical or ion density of the reaction gas.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to semiconductor manufacturing of semiconductor integrated circuit devices (IC).
The present invention relates to a dry etching apparatus for performing dry etching on a wafer to be etched, such as a wafer.

[Conventional technology]

FIG. 3 is a longitudinal cross-sectional view schematically showing main surface components of an example of a conventional dry etching apparatus.

In the figure, (1) is a vacuum container in which dry etching is performed, and (2) and (3) each have a disk shape and are arranged to face each other with a space between them in the vacuum container (1). An upper electrode plate and a lower electrode plate (4) are provided in the upper gt
The upper electrode plate pull-out rod (5) is fixed to the center of the upper surface of the electrode plate 2), and the other end is insulated and penetrates the top plate of the vacuum container (1), and is provided to the outside. A lower electrode plate pull-out rod (6) whose end is fixed to the center of the lower surface of the lower electrode plate (3) and whose other end is insulated and penetrates the bottom plate of the vacuum container (1) and exits to the outside. ) is a through hole (7) formed along the axis of the upper electrode plate pull-out rod (4) from the lower surface of the upper electrode plate (2) to the upper end surface of the upper electrode plate pull-out rod (4). The part is a through hole (
6) a gas introduction tube fixed to the upper end surface of the lower electrode plate pull-out rod (4) so as to communicate with the lower electrode plate pull-out rod (4) and introducing a reaction gas for dry etching into the vacuum container (1) through the through hole (6);
(8) has one end fixed to the bottom plate of the vacuum container (1) so as to penetrate through it and open into the vacuum container (1), and is used for gas exhaust to exhaust the reaction product gas in the vacuum container (1). tube,(
9) vi A self-biasing capacitor with one terminal connected to the upper electrode plate pull-out rod (4), αQ with one output terminal connected to the other terminal of the capacitor (9), and the other output terminal connected to the other terminal of the capacitor (9). It is connected to the lower electrode plate pull-out rod (5) and is grounded, and is connected to the vacuum vessel (1) through the through hole (6).
This is a high-frequency power generator that outputs high-frequency power to radicalize or ionize the dry etching reaction gas introduced into the dry etching chamber (active state of molecules or atoms). Note that (7) is a semiconductor wafer placed on the upper surface of the lower electrode plate (5) and subjected to dry etching on the processed surface, or a film to be etched such as a silicon oxide film to be dry etched on the upper surface. Semiconductor wafers (
In this specification, these semiconductor wafers will be referred to as "wafers to be etched").

In conventional dry etching equipment configured in this way, when performing dry etching, the gas exhaust pipe (
After evacuating the inside of the vacuum container (1) to a high vacuum through 8),
A dry etching reaction gas is introduced into the vacuum vessel (1) through the gas introduction pipe (7) and the through hole (6), which reacts with the wafer to be etched to produce a volatile gas. Next, the capacitor (
9) Through the upper electrode plate (2) and lower electrode plate (3)
A high frequency voltage is applied between. Then, the upper electrode plate (2) and the lower part 'I! Electrons are accelerated by the high frequency electric field generated between the electrode plate (3) and the accelerated electrons collide with the dry etching reaction gas, and this collision turns the reaction gas into radicals or ions. The radicals or ions of this reactive gas are
By colliding with and reacting with 7), trial etching of the wafer to be etched (2) is performed. Volatile reaction gas generated during this dry etching is exhausted to the outside through an exhaust pipe (8).

[Problem that the invention seeks to solve]

In the conventional dry etching apparatus as described above, the dry etching reciprocal (6 dregs) is introduced into the center between the upper polarization plate (2) and the lower electrode plate (3) through the Km hole (6). The concentration of the dry etching reaction gas is distributed such that it decreases as it progresses from the center between these two electrode plates [2), +3) toward the periphery.

On the other hand, the high frequency power supply device (from 10 to the upper '1 pole plate (2)
) and the bottom! The high frequency wave applied between the seed plate (3)
The electric field generated by one voltage is
+3) 2 in between are uniform. For this reason, the probability of collision between the '4 element and the dry etching reaction gas at the center between these - electrode plates (2), +3) is greater than the collision probability at the circumference, so that electrode plates L2), +
3) The radicalization efficiency or ionization efficiency due to collision with electrons of the dry etching reaction gas in the central region between the two is higher than the radicalization efficiency or ionization efficiency in the peripheral region. Therefore, the radical density or ion density of the dry etching reaction gas in the center between the electrode plates (2) and (3) is higher than the radical density or ion density of the dry etching reaction gas in the peripheral area. Another problem is that the dry etching rate on the temporarily etched quaternary ring becomes non-uniform due to collision with ions.

The present invention was made in order to solve this problem, and aims to provide a dry etching apparatus in which the speed of dry etching on a wafer to be etched is uniform due to the collision of a reactive gas for dry etching with radicals or ions. purpose.

[Means for solving problems]

The dry etching apparatus according to the present invention includes the above-mentioned division,
The concentration of the dry etching reaction gas between the central disk, the plurality of annular plates, and the lower electrode plate, the probability of collision with electrons, and the efficiency of radicalization or ionization due to collision with electrons are considered. Then, a high frequency voltage is applied so that the radical density or ion density of the reaction gas between these becomes uniform.

[Effect]

In the apparatus of the present invention, the radical density or ion density of the reaction residue for dry etching is made uniform between the central disk and the number of annular plates constituting the upper electrode and the lower electrode plate. By applying a high frequency voltage, the radicals or 7'C of the dry etching reaction gas generated between them collide with ions, thereby uniformizing the dry etching speed of the etching target wafer.

〔Example〕

FIG. 1 is a longitudinal sectional view schematically showing the main components of an embodiment of the present invention.

In the figure, the same symbols as those shown in FIG. 3 indicate equivalent parts. (2a), (2b) and (2)) are obtained by dividing the upper electrode plate (2) shown in Fig. 3 with a space between each other, as shown in the plan view in Fig. 2. A central disk, a first annular plate, a second annular plate, and (4b) and (4c) each have one end to which an upper electrode plate pull-out rod (4a), which is a component of the upper electrode of the embodiment, is fixed. The first end is fixed to the upper surfaces of the two annular plates (2b) and (2c), and the other end is insulated through the top plate of the vacuum container (1) and extends outside through the page. Annular plate pull-out rod and second annular plate pull-out group, (10a), αO
b) and 00C), one of the output terminals is a self-bias capacitor (%), a self-bias capacitor (%), a self-bias capacitor (9b), and a self-bias capacitor (9c).
Pull out the upper electrode plate via (4a).

Annular plate pull-out rod (4b) and annular plate pull-out rod (4
c), and the other output terminal is connected to the lower electrode plate pull-out rod (5).

In the dry etching apparatus configured as described above, when dry etching is performed, the vacuum container (1) is first evacuated to a high vacuum through the gas exhaust pipe (8), and then the gas inlet pipe (7 ) and the through hole (6) into the vacuum vessel (1) to introduce dry etching scum that reacts with the quay 71 (7) to be etched to produce a volatile gas. Next, a central disk (2a) and two annular plates (
2b), (2c) and the lower electrode plate (5), considering the concentration of the reaction residue for dry etching, the probability of collision with electrons, and the efficiency of radicalization or ionization due to collision with electrons. The high frequency power generator (10a), αOb), Q
Oc) to capacitor (9a).

(9b), (9c) and pull-out rod (4a),
(4b), (4c) through the central disk (2a) and two annular plates (2b), ■) and the lower electrode plate (5)
applied between. Then, the center disk (2a), two annular plates (2b), (2c) and the lower electrode plate (
5) Since the radical density or ion density of the dry etching reaction gas generated between these is made uniform, the etching target H/ /f I+l − due to collision with the radicals or ions of the reaction gas between them. I-
+, m 8/7+L L-4 〒 , -1!
-/ /7' t 16 -A: Become a foreigner.

In this embodiment, the high-frequency 'voltages applied between the center disk (2a), the two annular plates (2b) and (2c), and the lower electrode plate (3) are separate high-frequency components. Generator (10a), αOb), (10c)
+7) Output voltage is not limited to this, but even a divided voltage obtained by dividing the output 'd voltage of one high frequency power generator can have the same effect as this embodiment.

〔Effect of the invention〕

As explained above, the present invention divides the upper electrode plate of the conventional device into a central disk and a plurality of annular plates concentric to the central disk, spaced apart from each other by the threshold of each other. A high frequency voltage is applied between the plate, the plurality of annular plates, and the lower electrode plate so that the radical density or ion density of the dry etching reaction gas is uniform between them. The dry etching rate on the etched wafer is made uniform due to the collision of the dry etching reaction residue with radicals or ions.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view schematically showing an embodiment of the present invention;
FIG. 2 is a plan view showing the constituent elements of the upper electrode of this embodiment, and FIG. 3 is a vertical sectional view schematically showing an example of a conventional dry etching apparatus. In the figure, (1) is a vacuum vessel, (2) is an upper electrode plate,
(2&) is a central disk, @J> and (2c) are annular plates,
(3) is the lower electrode plate, CIG, (10a) and α
Ob) is a high frequency power generator, and Ob is a wafer to be etched. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) comprising a vacuum container in which dry etching is performed, and an upper electrode plate and a lower electrode plate each having a disc shape and provided in the vacuum container so as to face each other with a space therebetween; A wafer to be etched is placed on the upper surface of the lower electrode plate, a reactive gas for dry etching is introduced from the center of the lower surface of the upper electrode plate, and a high frequency voltage is applied between the two electrode plates to evaporate the reactive gas. In an apparatus that performs dry etching of the wafer to be etched by radicalization or ionization, the upper electrode plate is divided into a central disk and a plurality of annular plates concentric to the central disk with intervals between them. and applying a high frequency voltage between the central disk, the plurality of annular plates, and the lower electrode plate so that the radical density or ion density of the reaction gas between them becomes uniform. Dry etching equipment featuring: