KR101435973B1 - Wafer back cleaning device and method - Google Patents

Abstract

The present invention relates to a wafer cleaning apparatus and method, and more particularly, to a wafer cleaning apparatus and method. An upper electrode disposed in the chamber and injecting gas to a wafer loaded in the chamber; At least one wafer support stand spaced apart from the upper electrode to support the wafer; A wafer holder supporting an edge of the wafer supported by the wafer support and raising the wafer so as to have a gap with the upper electrode; And a lower electrode having a gap between the lower portion of the wafer held by the wafer holder and a gas sprayed to the rear surface of the wafer.

The wafer rear surface cleaning apparatus and method as described above can simultaneously etch the front edge portion and the rear surface of the wafer, thereby improving the efficiency. By adjusting the intensity of the plasma, the rear surface of the wafer is etched partly, So that the electrodes can be prevented from adhering to the wafer, thereby preventing breakage of the wafer.

Plasma, chamber, electrode, low frequency, high frequency, wafer, holder, discharge hole, etching

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a wafer cleaning apparatus and method, and more particularly to a wafer cleaning apparatus and method which can simultaneously etch a front edge portion and a rear surface of a wafer, thereby improving efficiency and controlling the intensity of plasma to differently etch the rear surface of the wafer, The present invention relates to a wafer rear surface cleaning apparatus and method for preventing a damage of a wafer by preventing a deposition of an electrode and a wafer by uniformly treating the wafer so that a residual time of the plasma generated between the electrodes can be maintained constant.

Generally, in a wafer processing apparatus, a thin film is deposited on the entire surface of a wafer and etched to manufacture a device having a predetermined pattern. That is, a thin film is deposited on a front surface of a wafer using a deposition apparatus, and a part of the thin film is etched by an etching apparatus in order to remove particles attached during a deposition process and an etching process.

As is well known, etching techniques for depositing wafers in a solvent or rinse to remove particles adhered to the surface of the wafer include wet etching using wet etching (wet etching) using a liquid fluoride liquid and gas such as tetrafluoromethane There is dry etching (dry etching).

Wet etching is effectively used to remove the photoresist layer applied to the wafer surface. However, since the process control is difficult, the operation cost such as the cleaning solution cost is high, and the productivity is not good due to the long run time, Dry etching is widely used.

Such conventional plasma etching equipment is disclosed in Application No. 10-2005-0101872.

1, the plasma etching apparatus includes an upper electrode unit 110 and a lower electrode unit 110, which are opposed to the upper electrode unit 110 in a vacuum chamber 100, and a semiconductor wafer (substrate) 120 is placed thereon And a lower electrode portion 126. The lower electrode unit 126 includes a lower electrode 128 to which power is supplied and an electrostatic chuck 130.

That is, the upper electrode part is configured to inject the reaction gas and to etch the entire surface of the wafer by the plasma generated by the electrode.

However, the etching process is a process of etching only the front surface of the wafer. In the rear surface of the wafer, the particles generated during the deposition process or the etching process are left without being removed. These particles may cause the wafer to warp in the subsequent process, And the like.

In addition, since the etching of the edge of the wafer is not performed smoothly, the particles deposited on the edge affect the circuit, the plasma is not smoothly discharged, the etched surface of the wafer becomes uneven, There is a concern that the wafer may adhere to the electrode portion.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to simultaneously etch a front edge portion and a rear surface of a wafer, to differently etch the rear surface of the wafer by controlling the intensity of plasma, And to prevent the electrodes and the wafer from adhering to the wafer back surface cleaning apparatus and method.

According to an aspect of the present invention, there is provided a plasma processing apparatus comprising: a chamber; An upper electrode disposed in the chamber and injecting gas to a wafer loaded in the chamber; At least one wafer support stand spaced apart from the upper electrode to support the wafer; A wafer holder supporting an edge of the wafer supported by the wafer support and raising the wafer so as to have a gap with the upper electrode; A lower electrode having a gap between the lower portion of the wafer held by the wafer holder and a gas sprayed to the rear surface of the wafer; .

Also, there is provided a method comprising: a first step of loading a wafer into a chamber; A second step of placing the wafer on top of a wafer support frame fixed within the chamber; A third step of raising the wafer so that the gap between the upper electrode and the upper electrode is maintained by supporting the edge of the wafer placed on the wafer support with a wafer holder; A fourth step of raising the lower electrode upward so as to have a gap with the wafer supported on the wafer holder; A fifth step of etching the front edge portion and the rear surface of the wafer spaced apart from the lower electrode and the upper electrode by plasma; A sixth step of lowering the lower electrode after etching; A seventh step in which the wafer having the front edge portion and the rear surface processed between the upper electrode and the lower electrode is seated on the wafer support by the lowering of the wafer holder; An eighth step of unloading the wafer holder out of the chamber; . ≪ / RTI >

As described above, the apparatus and method for cleaning the rear surface of a wafer according to the present invention improve the efficiency by simultaneously etching the front edge portion and the rear surface of the wafer, etch the rear surface of the wafer differently by controlling the intensity of the plasma, It is possible to maintain uniformity of the plasma remaining time between the wafer and the electrode so as to increase the uniformity of the wafer processed surface and to prevent the electrodes and the wafer from adhering, thereby preventing breakage of the wafer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a view showing the entire structure of a wafer rear surface treating apparatus according to the present invention. FIG. 3 is a view showing a state in which a wafer according to FIG. FIG. 5 is a view showing a state in which the lower electrode according to FIG. 2 rises and the rear surface of the wafer is subjected to plasma processing.

As shown in these drawings, a wafer rear surface cleaning apparatus and method according to a preferred embodiment of the present invention includes a chamber 100; An upper electrode (200) provided in the chamber (100) and injecting gas to the wafer (S) loaded in the chamber (100); At least one wafer support stand (300) spaced apart from the upper electrode (200) to support the wafer (S); A wafer holder 400 supporting the edge of the wafer S supported by the wafer support table 300 to raise the wafer S so as to have a gap with the upper electrode 200; And a lower electrode 500 having a gap between the lower portion of the wafer S supported by the wafer holder 400 and a gas sprayed to the rear surface of the wafer S.

In addition, a first step of loading the wafer S into the chamber 100; A second step of placing the wafer S on top of the wafer support table 300 fixed in the chamber 100; A third step of raising the wafer S so that a gap between the wafer S and the upper electrode 200 is maintained by supporting the edge of the wafer S mounted on the wafer support table 300 with the wafer holder 400; A fourth step of raising the lower electrode 500 upward so as to have an interval with the wafer supported on the wafer holder 400; A fifth step of etching a front edge portion and a rear surface of the wafer S spaced apart from the lower electrode 500 and the upper electrode 200 by plasma P; A sixth step of lowering the lower electrode (500) after etching; A seventh step in which the wafer S having the front edge portion and the rear surface processed between the upper and lower electrodes 200 and 500 is seated on the wafer support table 300 by the lowering of the wafer holder 400; An eighth step of unloading the wafer holder 400 to the outside of the chamber 100; .

The wafer rear surface cleaning apparatus and method of the present invention is for etching the particles deposited at the front edge portion and the rear surface of the wafer (S).

The chamber 100 may be formed in a cylindrical or rectangular box shape having a space therein, and may have a top-bottom structure or a structure that is divided into two sides.

An opening and closing part 110 through which the wafer S enters and exits is provided at one side of the chamber 100 and an exhaust device 120 for discharging particles generated in the etching process to the outside of the chamber 100 is provided at one side.

The exhaust device 120 may function not only to discharge the particles but also to make the inside of the chamber 100 vacuum in a state where the opening and closing part 110 of the chamber 100 is closed, May be provided separately with a separate vacuum means (not shown) for evacuating the inside of the chamber 100 only by the function of exhaust.

The wafer support table 300 has one side fixed to the inner lower part of the chamber 100 and the other side extended to be spaced apart from the lower part of the upper electrode 200.

In order to stably support the wafers S, at least three or more wafers S are preferably arranged at the same interval, but the wafers S may be provided in a larger number. In order to stably support the wafers S, The end portion may be formed into a wide flat plate shape.

The upper electrode 200 is preferably formed in a circular plate shape corresponding to the shape of the wafer S, but may be formed in various shapes without being limited thereto. In addition, it can be manufactured using various materials such as an anodized aluminum material and ceramics.

Power is applied to the upper electrode 200 through the upper power unit 240, and a non-reactive gas is supplied to the center portion and a reactive gas is supplied to the edge portion from an external gas supply unit (not shown).

A plurality of injection nozzles (not shown) are uniformly formed in the lower portion of the upper electrode 200 so that the non-reactive gas and the reactive gas can be injected.

Here, the non-reactive gas is injected from the nozzle portion at the central portion of the upper electrode 200 to the central portion of the wafer, the reactive gas is injected from the lower edge nozzle portion of the upper electrode 200 to the edge portion of the wafer, A plurality of injection nozzles may be formed along the outer edge of the wafer 200 to spray the reactive gas to the edge of the wafer S. [

The reactive gas includes CF 4, CHF 4, SF 6, C 2 F 6, C 4 F 8 And a gas including other elements capable of chemically etching a thin film or particles deposited on the wafer S may be included in addition to the fluorine-based or oxygen-based gas.

In addition, at least one anti-adhesion member 210 is provided on the lower edge of the upper electrode 200 along the circumferential direction, and a ring-shaped insulating ring 220 is provided on the outer edge of the upper electrode 200 And at least one ring-shaped cover ring 230 is provided on the lower portion of the insulating ring 220.

The deposition preventive member 210 is formed in a protrusion shape having a predetermined thickness using an insulating material and a plasma P is generated in the chamber 100 during the etching process so that the wafer S contacts the lower It is possible to prevent the wafer S from being damaged.

The insulating ring 220 is attached in a ring shape to surround the outside of the upper electrode 200 to concentrate the plasma P on the upper electrode 200. The insulating ring 220 may be formed of a material obtained by anodizing aluminum, Various materials can be used.

The cover ring 230 is attached to the lower portion of the insulating ring 220 in a ring shape and may be made of the same material as the insulating ring 220 or may be made of another material.

The covering 230 is formed to extend further downward than the upper electrode 200 so that the outer rim of the wafer S held apart from the lower portion of the upper electrode 200 during the etching process is in a state .

At this time, the outer edge of the upper electrode 200 adjacent to the inside of the covering 230 is maintained at a predetermined interval, and the edge of the wafer S is positioned at this interval, The process gas injected from the nozzle of the rim is intensively injected into the edge portion of the wafer S without being easily dispersed to the outside.

The upper electrode 200 may be provided with a cooling means (not shown) inside the upper electrode 200. The cooling means prevents the upper electrode 200 from rising above a certain temperature, P to protect the upper electrode 200. [

The gap between the upper electrode 200 and the wafer S is preferably maintained at 0.1 to 0.5 mm.

The wafer holder 400 has a ring shape surrounding the outside of the wafer support table 300 and is positioned below the upper end of the wafer support table 300 so that the wafer S is raised to a position spaced apart from the upper electrode 200 .

The wafer holder 400 may be formed as a circular ring or other shape so as to support the edge of the wafer S. A plurality of discharge holes 400a are formed along the circumference of the side wall of the wafer holder 400 Respectively. The discharge hole 400a allows the residence time of the plasma P generated between the wafer S and the electrode to be maintained constant.

The discharge hole 400a may be formed in various shapes, may be formed in the same shape along the circumference of the wafer holder 400, and may be formed in different shapes along the circumference of the wafer holder 400.

In addition, a holder holding portion 410 having a predetermined length may be formed outside the lower portion of the wafer holder 400. At least one lower driving shaft 420a which is lifted and lowered from the lower driving part 420 is connected to the lower part of the holder holding part 410 so that the wafer holder 400 can move up and down with the wafer S supported thereon.

The lower electrode 500 is formed in the same or corresponding shape as the upper electrode 200 and may be made of the same material as the upper electrode 200. However,

Power is applied to the lower electrode 500 through the lower power source unit 520 outside or inside the chamber 100 and the reactive gas supplied from the gas distributor 530 outside or inside the chamber 100 is injected upward A plurality of gas injection nozzles (not shown) are arranged uniformly on the upper portion.

That is, the reactive gas is injected through the injection nozzle, and power is applied to etch the rear surface of the wafer S with the plasma P.

To this end, a lower power source unit 520 for controlling the intensity of the plasma P by controlling the intensity of the frequency applied to the rear center portion and the edge portion of the wafer S is provided.

The lower power source unit 520 includes a low frequency power source unit 520a and a high frequency power source unit 520b so as to apply different power sources to the rear center or edge of the wafer S, respectively.

In addition, the gas distributor 530 controls the amount of the reactive gas injected to the rear center portion and the edge portion of the wafer S, respectively, so that the intensity of the plasma P can be varied.

That is, a different frequency is applied to the rear central portion and the edge portion of the wafer S by the low-frequency power source unit 520a and the high-frequency power source unit 520b, and the gas distributor 530 is applied to the rear central portion and the edge portion of the wafer S, The back surface of the wafer S can be uniformly etched by controlling the amount of the reactive gas to be injected.

At least one electrode drive shaft 510a, which is lifted and lowered by the electrode drive unit 510, is connected to a lower portion of the lower electrode 500. [

The wafer S is supported by the wafer holder 400 so that the wafer S is positioned at a position where the upper electrode 200 maintains a certain gap with the upper electrode 200 and then the upper electrode 200 is spaced apart from the rear surface of the wafer S The front edge portion of the wafer S and the backside etching operation are simultaneously performed.

In other words, the conventional wafer etching apparatuses can etch only the front surface of the wafer S, whereas the wafer rear surface cleaning apparatus and method of the present invention are capable of etching the front edge portion of the wafer S and the wafer S The particles deposited on the backside can be simultaneously etched, which is very effective.

Hereinafter, the method of the wafer rear surface cleaning apparatus according to the present invention will be described step by step with reference to FIG. 2 to FIG.

Step 1

As shown in FIG. 3, the pre-processed wafer S is horizontally loaded to the inside of the chamber 100 by loading means.

At this time, the loaded wafer S is positioned apart from the wafer support table 300 of the second stage, which will be described later, in a state where the central portion of the wafer S is aligned.

The chamber 100 may be formed in a cylindrical or rectangular box shape having a space therein, and may be formed as an upper-lower structure or a structure separated from the upper and lower sides.

An opening and closing part 110 through which the wafer S can enter and exit is provided at one side of the chamber 100 and an exhaust device 120 for exhausting the particles to the outside of the chamber 100 is provided at one side during the etching process.

The exhaust device 120 may function not only to discharge particles but also to make the inside of the chamber 100 vacuum in a state where the opening and closing part 110 of the chamber 100 is closed, May be provided separately with a separate vacuum means (not shown) for evacuating the inside of the chamber 100 only by the function of exhaust.

Step 2

As shown in FIG. 3, the wafer S is placed on top of the wafer support table 300 fixed in the chamber 100.

The wafer support table 300 has one side fixed to the inner lower part of the chamber 100 and the other side extended to be spaced apart from the lower part of the upper electrode 200.

In order to stably support the wafers S, at least three or more wafers S are preferably arranged at the same interval, but the wafers S may be provided in a larger number. In order to stably support the wafers S, The end portion may be formed into a wide flat plate shape.

Step 3

3, an edge of the wafer S mounted on the wafer support table 300 is supported by a ring-shaped wafer holder 400 so that the gap between the upper electrode 200 and the wafer S ).

The upper electrode 200 is preferably formed in a circular plate shape corresponding to the shape of the wafer S, but may be formed in various shapes without limitation. In addition, it can be manufactured using various materials such as an anodized aluminum material or a ceramic material.

Power is applied to the upper electrode 200 through the upper power unit 240, and a non-reactive gas is supplied to the center portion and a reactive gas is supplied to the edge portion from an external gas supply unit (not shown).

A plurality of injection nozzles (not shown) are uniformly formed in the lower portion of the upper electrode 200 so that the non-reactive gas and the reactive gas can be injected.

The non-reactive gas is injected from the nozzle portion at the center of the upper electrode 200 to the central portion of the wafer S and the reactive gas is injected from the lower edge nozzle portion of the upper electrode 200 to the edge portion of the wafer S The reactive gas may be injected into the edge portion of the wafer S by a plurality of injection nozzles formed along the outer edge of the upper electrode 200. [

The reactive gas may include a fluorine-based or an oxygen-based gas such as CF 4, CHF 4, SF 6, C 2F 6, and C 4F 8. In addition, the reactive gas may include other gases that can chemically etch thin films or particles deposited on the wafer S A gas containing an element may also be included.

In addition, at least one anti-adhesion member 210 is provided on the lower edge of the upper electrode 200 along the circumferential direction, a ring-shaped insulating ring 220 is provided on the outer edge of the upper electrode 200, At least one ring-shaped covering 230 is provided on the lower portion of the insulating ring 220.

The deposition preventive member 210 is formed in a protrusion shape having a predetermined thickness using an insulating material and a plasma P is generated in the chamber 100 during the etching process so that the wafer S contacts the lower It is possible to prevent the wafer S from being damaged.

The insulating ring 220 is attached in a ring shape to surround the outer edge of the upper electrode 200 to concentrate the plasma P on the upper electrode 200. The insulating ring 220 may be formed of a material obtained by anodizing aluminum, Can be used.

The cover ring 230 is attached to the lower portion of the insulating ring 220 in a ring shape and may be made of the same material as the insulating ring 220 or may be made of another material.

The covering 230 is formed to extend further downward than the upper electrode 200 so that the covering 230 surrounds the outer side of the wafer S which is spaced apart from the lower portion of the upper electrode 200 during the etching process do.

At this time, the outer edge of the upper electrode 200 adjacent to the inside of the covering 230 is maintained at a predetermined interval, and the edge of the wafer S is positioned at this interval, The process gas injected from the nozzle of the rim is intensively injected into the edge portion of the wafer S without being easily dispersed to the outside.

The upper electrode 200 may be provided with cooling means (not shown) inside the upper electrode 200. This cooling means prevents the upper electrode 200 from rising above a certain temperature, P to protect the upper electrode 200. [

The gap between the upper electrode 200 and the wafer S is preferably maintained at 0.1 to 0.5 mm.

At this time, at least one holder driving shaft 420a, which is raised and lowered by the lower holder driving part 420, is connected to the lower part of the wafer holder 400 and can be raised and lowered.

The wafer holder 400 has a ring shape surrounding the outside of the wafer support table 300 and is positioned below the upper end of the wafer support table 300 so that the wafer S is raised to a position spaced apart from the upper electrode 200 .

The wafer holder 400 may be formed as a circular ring or other shape so as to support the edge of the wafer S and a plurality of discharge holes 400a may be formed in the vertical body portion of the wafer holder 400 along the circumference. Respectively. The discharge hole 400a allows the residence time of the plasma P generated between the wafer S and the electrode to be maintained constant.

The discharge hole 400a may be formed in various shapes, may be formed in the same shape along the circumference of the wafer holder 400, or may be formed in different shapes along the circumference of the wafer holder 400.

In addition, a holder holding portion 410 having a predetermined length may be formed outside the lower portion of the wafer holder 400. At least one lower driving shaft 420a which is lifted and lowered from the lower driving part 420 is connected to the lower portion of the holder holding part 410 so that the wafer holder 400 can be raised and lowered while supporting the wafer S thereon.

Step 4

As shown in FIG. 4, the lower electrode 500 spaced apart from the wafer S supported by the wafer holder 400 is lifted upward to have a proper clearance with the wafer S, as shown in FIG.

The lower electrode 500 may be formed in the same or corresponding shape as the upper electrode 200 or may be made of the same material. However, the lower electrode 500 may be formed in a material different from or different from the upper electrode 200.

Power is applied to the lower electrode 500 through the lower power source unit 520 outside or inside the chamber 100 and the reactive gas supplied from the gas distributor 530 outside or inside the chamber 100 is injected upward A plurality of gas injection nozzles (not shown) are arranged uniformly on the upper portion.

That is, the reactive gas is injected through the injection nozzle, and power is applied to etch the rear surface of the wafer S with the plasma P.

To this end, a lower power source unit 520 is provided which controls the intensity of the frequency applied to the rear center portion and the edge portion of the wafer S to vary the intensity of the plasma P. [

The lower power source unit 520 may be divided into a low frequency power source unit 520a and a high frequency power source unit 520b so as to apply different power sources to the rear center or edge of the wafer S, respectively.

In addition, the gas distributor 530 controls the amount of the reactive gas injected to the rear center portion and the edge portion of the wafer S, respectively, so that the intensity of the plasma P can be varied.

At least one electrode drive shaft 510a, which is lifted and lowered by the electrode drive unit 510, is connected to a lower portion of the lower electrode 500. [

Step 5

5, etching the front edge portion and the rear surface of the wafer S spaced apart from the lower electrode 500 and the upper electrode 200 by plasma (P).

The lower power source unit 520 applies power to the rear central portion and the edge portion of the wafer S and supplies the gas to the upper and lower sides of the wafer S by applying power to the upper electrode 200 and the reactive gas to the non- Spray.

That is, the front edge portion of the wafer is etched with the plasma P generated between the upper electrode 200 and the wafer S, and the plasma P generated between the lower electrode 500 and the wafer S Etch the backside.

The lower electrode 500 applies different frequencies to the rear central portion and the edge portion of the wafer S via the lower power source unit 520 and the center portion and the edge portion of the wafer S via the gas distributor 530, The rear surface of the wafer S can be uniformly etched by spraying a different amount of reactive gas.

Step 6

The lower electrode 500 is lowered by the lower driving unit 420 to return to the original position after the rear etching process of the wafer S is completed as described above. .

Step 7

The wafer S having the front edge portion and the backside processed between the upper and lower electrodes 200 and 500 is placed on the wafer support table 300 by the lowering of the wafer holder 400.

Step 8

Thereafter, the vacuum is released, and the opening / closing means 11 is opened to unload the wafer (S) subjected to the plasma (P) processing to the outside of the chamber (100).

That is, the wafer holder 400 is positioned below the wafer support table 300, so that the wafer S is placed on the wafer support table 300 while descending, and only the wafer holder 400 is further lowered to the wafer support table 300 300, the wafer S is seated.

Then, the opening and closing part 110 of the chamber 100 is opened, and the loading means lifts the wafer S and unloads the wafer S horizontally out of the chamber 100.

As a result, the efficiency is improved by simultaneously etching the front edge portion and the rear surface of the wafer S, and the rear surface of the wafer S is etched differently by controlling the intensity of the plasma P, It is possible to uniformize the machined surface of the wafer S by keeping the residence time of the plasma P generated between the electrode and the wafer S constant, do.

Although the technical idea of the present invention has been specifically described in accordance with the above preferred embodiments, it is to be noted that the above-described embodiments are intended to be illustrative and not restrictive. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

1 is a view showing a conventional plasma processing apparatus.

Fig. 2 is an overall structural view of a wafer rear surface treating apparatus according to the present invention; Fig.

Fig. 3 is a view showing a state in which a wafer according to Fig. 2 is inserted and seated on a wafer support. Fig.

Fig. 4 is a view showing a state in which the wafer holder according to Fig. 2 raises the wafer to the working position; Fig.

Fig. 5 is a view showing a state in which the lower electrode according to Fig. 2 rises and the rear surface of the wafer is subjected to plasma processing; Fig.

  Description of the Related Art

 S ... Wafer P ... Plasma

 100 ... chamber 110 ... opening /

 120 ... exhaust device 200 ... upper electrode

 210: attachment preventing member 220: insulating ring

 230 ... Covering 240 ... Top power supply

 300 ... Wafer support 400 ... Wafer holder

 400a ... discharge hole 410 ... holder inner holder

 420 ... holder drive section 420a ... holder drive shaft

 500 ... lower electrode 510 ... electrode driver

 510a ... electrode drive shaft 520 ... lower power supply unit

 520a ... Low frequency power source unit 520b ... High frequency power source unit

 530 ... gas distributor

Claims (22)

A chamber 100; An upper electrode (200) provided in the chamber (100) and injecting gas to the wafer (S) loaded in the chamber (100); At least one wafer support stand (300) spaced apart from the upper electrode (200) to support the wafer (S); A wafer holder 400 supporting the edge of the wafer S supported by the wafer support table 300 to raise the wafer S so as to have a gap with the upper electrode 200; And a lower electrode (500) having a gap with a lower portion of the wafer (S) supported on the wafer holder (400) and injecting gas onto the rear surface of the wafer (S) Wherein the wafer holder (400) has a plurality of exhaust holes (400a) formed along the circumference thereof. A chamber 100; An upper electrode (200) provided in the chamber (100) and injecting gas to the wafer (S) loaded in the chamber (100); At least one wafer support stand (300) spaced apart from the upper electrode (200) to support the wafer (S); A wafer holder 400 supporting the edge of the wafer S supported by the wafer support table 300 to raise the wafer S so as to have a gap with the upper electrode 200; And a lower electrode (500) having a gap with a lower portion of the wafer (S) supported on the wafer holder (400) and injecting gas onto the rear surface of the wafer (S) The lower electrode 500 is provided with a lower power source unit 520 including a low frequency power source unit 520a and a high frequency power source unit 520b for controlling the intensity of a frequency applied to a center portion and an edge portion of the rear portion of the wafer S Wherein the wafer is cleaned. 3. The method according to claim 1 or 2, The upper electrode (200) At least one insulation ring 220 is formed on the outer side of the upper electrode 200 and at least one insulation ring 220 is formed on the lower side of the insulation ring 220, Wherein at least one covering (230) is provided. 3. The method according to claim 1 or 2, The lower electrode (500) And a gas distributor (530) for controlling the amount of reactive gas injected into the center portion and the edge portion of the rear portion of the wafer (S). 3. The method according to claim 1 or 2, The upper electrode (200) Characterized in that at least one protrusion-preventing member (210) is provided on the lower edge along the circumference of the wafer. 3. The method according to claim 1 or 2, The upper electrode (200) Wherein at least one insulating ring (220) is provided on an outer edge of the insulating ring (220), and at least one covering (230) is provided below the insulating ring (220). 6. The method of claim 5, The upper electrode (200) Wherein at least one insulating ring (220) is provided on an outer edge of the insulating ring (220), and at least one covering (230) is provided below the insulating ring (220). delete delete The method of claim 3, The lower electrode (500) And a gas distributor (530) for controlling the amount of reactive gas injected into the center portion and the edge portion of the rear portion of the wafer (S). The method according to claim 1, The upper electrode (200) At least one insulation ring 220 is formed on the outer side of the upper electrode 200 and at least one insulation ring 220 is formed on the lower side of the insulation ring 220, At least one covering 230 is provided, The wafer holder (400) A plurality of discharge holes 400a are formed along the circumference, The lower electrode (500) A lower power source unit 520 for controlling the intensity of a frequency applied to a central portion and an edge portion of the rear surface of the wafer S, And a gas distributor (530) for controlling the amount of reactive gas injected into the center portion and the edge portion of the rear portion of the wafer (S). A first step of loading the wafer S into the chamber 100; A second step of placing the wafer S on top of the wafer support table 300 fixed in the chamber 100; A third step of raising the wafer S so that a gap between the wafer S and the upper electrode 200 is maintained by supporting the edge of the wafer S mounted on the wafer support table 300 with the wafer holder 400; A fourth step of raising the lower electrode 500 upward so as to have an interval with the wafer supported on the wafer holder 400; A fifth step of etching a front edge portion and a rear surface of the wafer S spaced apart from the lower electrode 500 and the upper electrode 200 by plasma P; A sixth step of lowering the lower electrode (500) after etching; A seventh step in which the wafer having the front edge portion and the rear surface processed between the upper and lower electrodes 200 and 500 is seated on the wafer support table 300 by the lowering of the wafer holder 400; An eighth step of unloading the wafer holder 400 to the outside of the chamber 100; Wherein the wafer is cleaned. 13. The method of claim 12, The upper electrode (200) At least one insulation ring 220 is formed on the outer side of the upper electrode 200 and at least one insulation ring 220 is formed on the lower side of the insulation ring 220, Wherein at least one covering (230) is provided. 13. The method of claim 12, The wafer holder (400) Wherein a plurality of exhaust holes (400a) are formed along the circumference. 13. The method of claim 12, The lower electrode (500) A lower power source unit 520 including a low frequency power source unit 520a and a high frequency power source unit 520b for controlling the intensity of a frequency applied to a center portion and an edge portion of the rear portion of the wafer S, Wherein a gas distributor (530) is provided for controlling the amount of reactive gas injected into the central portion and the edge of the rear portion of the wafer (S). The method according to any one of claims 12, 14 and 15, The upper electrode (200) Wherein at least one protrusion-preventing member (210) is provided on the lower edge along the circumference of the wafer. The method according to any one of claims 12, 14 and 15, The upper electrode (200) Wherein at least one insulating ring (220) is provided on an outer edge of the insulating ring (220), and at least one covering (230) is provided below the insulating ring (220). 17. The method of claim 16, The upper electrode (200) Wherein at least one insulating ring (220) is provided on an outer edge of the insulating ring (220), and at least one covering (230) is provided below the insulating ring (220). 15. The method according to any one of claims 12 to 14, The lower electrode (500) And a lower power source unit 520 including a low frequency power source unit 520a and a high frequency power source unit 520b for controlling the intensity of a frequency applied to a center portion and an edge portion of the rear portion of the wafer S are provided. 15. The method according to any one of claims 12 to 14, The lower electrode (500) Wherein a gas distributor (530) is provided for controlling the amount of reactive gas injected into the central portion and the edge of the rear portion of the wafer (S). 20. The method of claim 19, The lower electrode (500) Wherein a gas distributor (530) is provided for controlling the amount of reactive gas injected into the central portion and the edge of the rear portion of the wafer (S). 13. The method of claim 12, The upper electrode (200) At least one insulation ring 220 is formed on the outer side of the upper electrode 200 and at least one insulation ring 220 is formed on the lower side of the insulation ring 220, At least one covering 230 is provided, The wafer holder (400) A plurality of discharge holes 400a are formed along the circumference, The lower electrode (500) A lower power source unit 520 for controlling the intensity of a frequency applied to a central portion and an edge portion of the rear surface of the wafer S, Wherein a gas distributor (530) is provided for controlling the amount of reactive gas injected into the central portion and the edge of the rear portion of the wafer (S).

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