KR20010038944A - Plasma etching apparatus - Google Patents

Abstract

PURPOSE: A plasma etcher is provided to prevent a wafer from being damaged by ions irradiated to the wafer, by varying and applying a positive power supply and a negative power supply to positive and negative electrodes, respectively. CONSTITUTION: A wafer(230) is mounted between a positive electrode and a negative electrode. The wafer is etched by using plasma generated by a high voltage. BC(blocking capacitor) provide RF power source of which direct current and a low frequency component are eliminated, to a switch(100). The switch makes a positive power supply and a negative power supply varied and supplied to respective electrodes.

Description

Plasma Etching Equipment {PLASMA ETCHING APPARATUS}

The present invention relates to an apparatus for manufacturing a semiconductor device, in particular, by switching the RF (RF) power applied to the chamber (chamber) during plasma etching to vary the positive and negative power to the lower electrode and the upper electrode in the chamber It relates to a plasma etching apparatus for supplying.

In general, a plasma etching method uses a reactive ion etching (RIE) method in which a wafer is mounted on a positive electrode side and ions generated from a plasma and an injected gas are etched by a collision.

1 is a schematic view showing a structure of a conventional plasma etching apparatus, as shown therein, a blocking capacitor (BC) receiving a RF power and removing direct current and low frequency components; It is composed of a lower electrode 11 and a lower electrode 12 to form and etch plasma on the wafer 13 mounted in the chamber 10 by RF power input from the coupling capacitor BC. The operation of the configured conventional device will be described.

First, when the wafer 13 to be etched is mounted on a wafer stage (not shown) installed in the chamber 10, gas is supplied into the chamber 10 through a gas injection plate (not shown).

In this case, a blocking capacitor BC receives RF power and removes DC and low frequency components and applies the same to the chamber 10.

Then, a negative power is applied to the upper electrode 12 installed above the chamber 10, and a positive power is applied to the lower electrode 11 installed on the wafer stage (not shown), thereby providing the chamber 10. Plasma is formed in this case, and a region called sheath is created by the difference in weight between ions and electrons, and a voltage difference (Self-DC) is generated between the plasma and the wafer 13.

Due to the voltage difference Self-DC, ions are incident in a direction perpendicular to the wafer 13, which hits the surface of the wafer 13 to perform anisotropic etching.

Here, when the voltage difference (Self-DC) between the plasma and the wafer 13 is small, as in the case where a negative power is applied after the wafer 13 is mounted on the lower electrode 11, the incident force of ions is weak. Thus, the surface of the wafer 13 is isotropically etched by activated particles called radicals.

As described above, when the wafer is mounted on a positive electrode during plasma etching and etched, when the RF power is increased to obtain a desired etching rate, the wafer surface is lost by ions having a high incident energy and negative. When the wafer is mounted on the electrode and etched, there is a problem that isotropic etching is performed by activated particles called radicals rather than etching by ions.

Accordingly, an object of the present invention is to provide a plasma etching apparatus, which is created to solve the conventional problems as described above, by varying and applying positive power and negative power to the lower electrode and the upper electrode by switching input power. There is this.

1 is a schematic view showing the structure of a conventional plasma etching apparatus.

Figure 2 is a schematic diagram showing the structure of the plasma etching apparatus of the present invention.

*** Description of the symbols for the main parts of the drawings ***

100: switch 200: chamber

210: lower electrode 220: upper electrode

230: wafer BC: coupling capacitor

RF: RF Power

In order to achieve the above object, the present invention provides a device for etching a wafer using a plasma generated by a high voltage after mounting a wafer between a positive electrode and a negative electrode. Receiving the removed RF power is characterized in that it further comprises a switch for switching so that the positive power and the negative power is supplied to each electrode variable.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic diagram showing the structure of the plasma etching apparatus of the present invention, as shown therein is a coupling capacitor (BC) for receiving a DC (RF) power source to remove direct current and low frequency components; A switch (100) for switching RF power applied from the coupling capacitor (BC); According to the present invention configured as the lower electrode 210 and the upper electrode 220 to form a plasma on the wafer 230 mounted in the chamber 200 by the power applied through the switch 100, The operation and operation of one embodiment will be described in detail.

First, when the wafer 230 to be etched is mounted on a wafer stage (not shown) installed in the chamber 200, gas is supplied into the chamber 200 through a gas injection plate (not shown).

At this time, the blocking capacitor BC receives RF power and removes direct current and low frequency components and applies the switch 100 to the switch 100. The switch 100 is initially located at the position of the contact point a and the chamber. A negative power is applied to the upper electrode 220 installed on the upper portion of the 200, and a positive power is applied to the lower electrode 210 provided on the wafer stage (not shown).

Then, plasma is formed through the electrodes 210 and 220 to form an etching of a reactive ion etching (RIE) method. At this time, a region called sheath is formed by the difference in weight between ions and electrons, and the plasma and the wafer 230 are formed. ), There is a voltage difference (Self-DC).

Due to the voltage difference Self-DC, ions are incident in a direction perpendicular to the wafer 230, which hits the surface of the wafer 230 to perform anisotropic etching.

Subsequently, when a predetermined time passes and the switch 100 is switched from the contact point a to the contact point b in the finishing step of the process, a positive power is applied to the upper electrode 220 installed on the chamber 200 and the wafer stage ( Negative power is applied to the lower electrode 210 installed in the drawing (not shown) so that the etching by the ions becomes negligibly small, and the etching is performed by radicals, which are another particles in the plasma.

That is, in the initial stage of the etching process, a rapid etching is performed by the RIE method, and in the last step, the etching is performed by radicals to chemically etch the surface etched by the ions.

As described above, the present invention has an effect of reducing damage caused by ions incident on the wafer by varying and applying a positive power source and a negative power source to each electrode.

Claims (1)

An apparatus for etching a wafer by using a plasma generated by a high voltage after mounting a wafer between a positive electrode and a negative electrode, each of the electrodes receiving an RF power source from which direct current and low frequency components are removed through a coupling capacitor Plasma etching apparatus characterized in that it further comprises a switch for switching so that the positive power and the negative power is supplied to vary.