KR20010035657A - Apparatus for plasma etching - Google Patents

Abstract

PURPOSE: A plasma etcher for manufacturing a semiconductor is provided to easily control an etch rate and etch uniformity of a wafer, by varying a plasma formation region to vary a plasma density. CONSTITUTION: Process gas is induced to a process chamber of which inside pressure is controlled. The first radio frequency voltage is applied to a cathode(12) located in side the process chamber. The second radio frequency voltage is applied to a coil(11) located outside the process chamber. A transfer unit varies a location of the coil to control a plasma formation region formed between the cathode and the coil.

Description

Plasma etching apparatus for semiconductor manufacturing {Apparatus for plasma etching}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching apparatus for semiconductor manufacturing, and in particular, by varying the position of a coil to which a high frequency voltage is applied, so that the plasma region within the chamber can be variably controlled, thereby enabling optimization of etching rate and etching uniformity suitable for process conditions. I did it.

In general, plasma etching is a complete dry etching system, and plasma gas may be generated by electrical breakdown to cause a strong chemical reaction depending on the type of gas. That is, the plasma dry etching may etch a silicon layer, a silicon nitride film, a polysilicon film, a silicon oxide film, or the like in semiconductor manufacturing.

1 is a view for explaining a conventional semiconductor manufacturing plasma etching apparatus used for such plasma etching, the conventional semiconductor manufacturing plasma etching apparatus has a process chamber 10 in which a process gas is introduced and pressure control, process chamber There is an electrostatic chuck 13 inside which the wafer to be etched by the plasma is fixed.

In addition, a cathode 12 for forming a plasma region is located inside the chamber, and a first high frequency voltage of 13.56 MHz is applied to the cathode 12.

A coil 11 for forming a plasma region is fixedly installed between the cathode 12 and the outside of the chamber, and a second high frequency voltage of 12.56 MHz is applied to the coil 11.

In the plasma etching apparatus for semiconductor fabrication having such a structure, first, the wafer is etched, and when a wafer (not shown) is positioned on the electrostatic chuck 13, process gas is introduced into the chamber 10 and the pressure is adjusted.

When the first high frequency power of 13.56 MHz is applied to the cathode 12 and the second high frequency power of 12.56 MHz is simultaneously applied to the coil 11, electrons of the process gas are excited and collide with each other to increase the density of ions. A constant plasma region is formed between the cathode 12 and the coil 11.

When the plasma region is formed, the plasma measuring device measures the density of the plasma to adjust the flow rate of the process gas and the pressure inside the chamber to form a constant plasma density.

The ions in the plasma region are then directed to the wafer surface on the electrostatic chuck 13 by the first high frequency power source applied to the cathode 12 to etch the film.

However, the etching of the wafer by plasma changes the etching rate and the uniformity of the etching by various variables in the process.

That is, since the plasma forming region is sensitively changed to process conditions such as pressure, process gas flow rate, and applied voltage in the chamber, if the process conditions are not properly controlled, the plasma forming region is changed to lower the etching rate and etching uniformity of the wafer. do.

In particular, the conventional plasma etching apparatus for semiconductor manufacturing has a problem that the coil is fixed so that the plasma forming region formed between the coil and the cathode can only be adjusted by the pressure inside the chamber and the flow rate of the process gas.

Therefore, the conventional plasma etching apparatus for semiconductor manufacturing has a problem that it is not easy to control the etching rate and etching uniformity of the wafer.

Accordingly, an object of the present invention is to provide a plasma etching apparatus for semiconductor manufacturing that can change the plasma density by varying the plasma forming region so as to easily control wafer etching rate and etching uniformity.

Therefore, in order to achieve the above object, the plasma etching apparatus for manufacturing a semiconductor according to the present invention includes a process chamber in which process gas is introduced and an internal pressure is controlled, a cathode disposed in the process chamber and to which a first high frequency voltage is applied, and a process And a coil positioned outside the chamber to which the second high frequency voltage is applied, and moving means for controlling a plasma region formed between the cathode and the coil by varying the position of the coil.

1 is a view for explaining a conventional plasma etching apparatus for manufacturing a semiconductor.

2 is a view for explaining a plasma etching apparatus for manufacturing a semiconductor according to the present invention.

■ Brief description of the main parts of the drawing ■

10 chamber 11 coil

12 cathode (cathode) 13 electrostatic chuck

100: insulation guide 101: screw groove

102: threaded rod 103: Timing Belt

104: drive motor

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the plasma etching apparatus for semiconductor manufacturing according to the present invention.

As shown in FIG. 2, the plasma etching apparatus for semiconductor manufacturing according to the present invention includes a process chamber 10 in which an electrostatic chuck 13 for fixing a wafer to be etched is located.

Although not shown, the process chamber 10 has a gas inlet and an exhaust port through which the process gas is introduced and the reaction gas is exhausted, and the internal pressure is controlled by a pressure regulator.

A cathode 12 is positioned at an inner lower end of the process chamber 10, and a first high frequency voltage of 13.56 MHz is applied to the cathode 12.

In addition, a coil 11 to which a second high frequency voltage of 12.56 MHz is applied is wound several times on the outer upper end of the process chamber 10, and the coil 11 is provided with a moving means to change its position in the up and down directions. .

As a moving means of the coil 11, first, there is a coil guide piece 100 which surrounds the coil 11 outside the chamber and has a screw groove 101 formed thereon.

The screw rod 101 and the screw rod 102 that are treated with the screw are coupled to the screw groove 101, and the screw rod 102 is connected to the screw rod 102 and the timing belt 103 to rotate. Comprising 102 is screwed along the groove 101 is made of a drive motor 104 for conveying the coil guide piece 100 in the up and down direction.

Here, the coil guide piece 100 and the screw rod 102 serve as an insulator so that the second high frequency voltage applied to the coil 11 does not flow, and the drive motor 104 is a stepping motor.

The plasma etching according to the present invention having such a structure will be described.

First, when the wafer is placed on the electrostatic chuck 13, the process gas is introduced into the chamber 10 and the pressure is adjusted.

Then, when the first high frequency power source of 13.56 MHz is applied to the cathode 12 and the second high frequency power source of 12.56 MHz is simultaneously applied to the coil 11, electrons of the process gas are excited and actively collide with each other to actively move, The density is increased to form a constant plasma region between the cathode 12 and the coil 11.

At this time, the plasma density inside the chamber 10 is measured through a separate plasma density detection device (not shown).

Then, the flow rate of the process gas is adjusted according to the measured plasma density, the pressure inside the chamber 10 is controlled, and the etching rate and the etching uniformity of the wafer are controlled.

To this end, the driving motor 104 rotates the timing belt 103 so that the screw rod 102 moves up and down along the screw groove 101 of the threaded insulating guide piece to change the plasma region.

That is, when the insulation guide piece is moved upward, the distance between the coil 11 and the cathode 12 is widened to increase the plasma formation region, thereby reducing the plasma density. When the insulation guide piece is moved downward, the coil 11 and the cathode ( As the spacing of 12) is narrowed, the plasma formation area is reduced, and the density is increased, thereby inducing a desired wafer etching rate and etching uniformity.

When the plasma region is formed, ions in the plasma region are guided to the wafer surface on the electrostatic chuck 13 by the first high frequency voltage applied to the cathode 12 to etch the film.

As described above, in the plasma etching apparatus for semiconductor manufacturing according to the present invention, the plasma density control according to the process conditions is performed not only by the process gas flow rate and the pressure change in the process chamber but also by the variation of the plasma region according to the position of the coil. Precise plasma density control is possible.

Therefore, the desired wafer etching rate and the uniformity of etching can be improved to obtain the precision of the etching process.

Claims (3)

A process chamber in which process gas inflow and pressure inside are adjusted; A cathode positioned inside the process chamber and to which a first high frequency voltage is applied; A coil positioned outside the process chamber and to which a second high frequency voltage is applied; Plasma etching apparatus for semiconductor manufacturing comprising a moving means for adjusting the position of the coil to adjust the plasma forming region formed between the cathode and the coil. The method according to claim 1, The means for moving, A fixing piece having a screw groove formed therein and surrounding the coil; A screw rod which is screwed with the screw groove; Plasma etching apparatus for semiconductor manufacturing characterized in that the screw rod is connected to the mutual timing belt and made of a stepping motor so that the screw rod is elevated by the screw groove. The method according to claim 2, The fixing piece and the screw rod is a plasma etching apparatus for semiconductor manufacturing, characterized in that consisting of an insulator.