KR101399904B1 - Apparatus for cleaning substrate with plasma - Google Patents

Abstract

The present invention relates to a substrate cleaning apparatus capable of cleaning particles generated during a substrate processing process such as etching and vapor deposition using plasma, and a substrate cleaning apparatus of the present invention includes: And plasma is generated on the lower surface to clean the lower surface and the side surface of the substrate.

Substrate, cleaning, dry cleaning, plasma, backside

Description

[0001] APPARATUS FOR CLEANING SUBSTRATE WITH PLASMA [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning apparatus capable of cleaning particles generated during a substrate processing process such as etching, deposition, etc. using plasma.

Particles such as fine dust and moisture in the production stage of the integrated circuit manufactured by the process of developing and etching the circuit pattern on the wafer surface must be actively removed because it damages the formation of the circuit pattern.

Generally, particles generated by external factors can be prevented in advance through purification of the process atmosphere through a clean facility, but the particles of internal factors generated during the manufacturing process can not be prevented in advance. Therefore, wafers are subjected to various cleaning processes in the process of moving between processes.

As is well known, cleaning of wafers is known as wet cleaning for removing particles on the surface by dipping in a solvent or rinse, and dry cleaning for removing the surface by plasma etching.

The wet cleaning is effectively used to remove the photoresist layer applied to the wafer surface, but it is difficult to control the process, and the operation cost such as the cost consumed in the cleaning liquid is high, and the productivity is poor due to the long process time. Therefore, at present, a dry cleaning method using plasma is widely used.

Examples of such a dry cleaning apparatus include a method of removing a photoresist layer or the like applied to the wafer surface by etching and a bevel etching method of removing particles deposited on the upper and lower edges of the wafer placed on the stage.

However, such a dry cleaning apparatus also fails to clean the back surface of the wafer. However, the particles present on the backside of the wafer cause problems in the horizontality of the wafer when the wafer is placed on the stage. When the wafer mounted on the stage is not parallel to the stage surface, there arises a fatal problem that uniform processing can not be performed on the substrate in a subsequent process such as exposure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a substrate cleaning apparatus capable of simultaneously or sequentially cleaning a substrate to a back side as well as a side surface thereof using plasma.

According to an aspect of the present invention, there is provided a substrate cleaning apparatus for cleaning a bottom surface and a side surface of a substrate by generating a plasma on a side surface and a bottom surface of the substrate while gripping an upper surface of the substrate.

Specifically, the cleaning apparatus of the present invention includes: a vacuum chamber capable of maintaining the inside thereof in a vacuum state; An electrostatic chuck disposed on the upper side of the vacuum chamber and fixing the substrate in contact with the upper surface of the substrate so that the substrate edge is exposed; A moving chuck disposed below the inside of the vacuum chamber and drivable in a vertical direction; An upper insulator disposed on a side of the electrostatic chuck at a predetermined distance from a side surface of the electrostatic chuck; A substrate holder disposed on a side of the transfer chuck and surrounding the substrate such that a lower surface and a side surface of the substrate fixed to the electrostatic chuck are exposed; A lower insulator disposed outside the substrate holder and facing the upper insulator; An upper gas supply path formed in the electrostatic chuck for supplying a process gas to a space between the side surface of the electrostatic chuck and the upper insulator; A lower gas supply path formed on the transfer chuck to supply a process gas to a space between the substrate and the transfer chuck; And RF applying means formed at any one of the electrostatic chuck and the moving chuck for applying RF power.

The substrate cleaning apparatus of the present invention further includes a lift pin formed to penetrate through the transfer chuck and driven in the vertical direction to receive a substrate loaded from the outside, so that loading and unloading of the substrate into the substrate cleaning apparatus can be easily performed So that it is preferable.

Meanwhile, the electrostatic chuck of the present invention is formed such that its side faces are stepped by the thickness of the upper insulator, and the electrostatic chuck, the upper insulator, the substrate holder and the lower insulator are closely contacted to form a donut- It is possible to provide a space in which the side plasma can be formed.

At this time, the substrate holder is preferably formed as a chamfered surface having a portion facing the side surface of the substrate.

On the other hand, it is preferable that the electrostatic chuck is further provided with an upper cooling flow path for cooling the electrostatic chuck by circulating the cooling medium, because the temperature of the wafer gripped by the electrostatic chuck can be adjusted.

Further, it is preferable that the inside of the transfer chuck is further provided with a lower cooling flow path for circulating the cooling medium to cool the transfer chuck, because the temperature rise of the transfer chuck by the back plasma can be suppressed.

The electrostatic chuck of the present invention is preferably arranged so as to be able to be driven in the vertical direction because it is advantageous in forming a space for forming a back surface plasma for cleaning the back surface of the substrate.

Further, it is preferable that a baffle is further provided between the lower insulator and the side wall of the vacuum chamber, and the baffle may be arranged to be vertically drivable.

According to the present invention, it is possible to simultaneously clean the edge and the back surface of the substrate by simultaneously forming a plasma on the side surface and the back surface side of the substrate, and also have the effect of drastically shortening the processing time.

Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1, the substrate cleaning apparatus 1 according to the present embodiment includes a vacuum chamber 10, an electrostatic chuck 20, a moving chuck 30, an upper insulator 40, a substrate holder 50, A lower insulator 60, an upper gas supply path 70, a lower gas supply path 80, and an RF applying means 90.

First, the vacuum chamber 10 has an overall shape of the substrate cleaning apparatus 1 according to the present embodiment, and has a structure capable of keeping the internal space in a vacuum state. Accordingly, the vacuum chamber 10 is sealed and the gate valve 14 is formed in the substrate entry / exit port 12 through which the substrate enters and exits. When the substrate entry / exit process is completed, the substrate entry / exit port 12 is sealed . The vacuum chamber 10 is provided with a pumping system 18 for evacuating the gas in the chamber interior to create a vacuum state and a venting system for injecting gas to make the pressure inside the chamber at atmospheric pressure ).

Further, an insulating member may be further provided on the inner wall of the vacuum chamber 10 according to the present embodiment. That is, an insulating member such as ceramic may be attached to the inner wall surface of the vacuum chamber 10 to prevent damages to the inner wall of the chamber by the plasma, and the volume of the chamber may be reduced to reduce the time required for pumping .

Next, the electrostatic chuck 20 is disposed inside the vacuum chamber 10, and is a component for fixing the substrate in contact with the upper surface of the substrate W so that the substrate edge is exposed. Since the substrate cleaning apparatus 1 according to the present embodiment cleans not only the edge of the substrate W but also the back surface of the substrate, the back surface and the edge portion of the substrate must be exposed. Accordingly, the electrostatic chuck 20 comes into contact with the upper surface of the substrate so as to expose the edge of the substrate W, thereby lifting the substrate, thereby exposing the back surface of the substrate W. As shown in FIGS. 1 and 2, the electrostatic chuck 20 of the present embodiment is formed such that its side faces are stepped by the thickness of the upper insulator 40 so that the edges and top edge portions of the substrate are exposed.

Here, the electrostatic chuck 20 of the present embodiment grips the substrate W using electrostatic force, so that the circuit formed on the upper surface of the substrate is not damaged. Therefore, a DC voltage for generating an electrostatic force is applied to the electrostatic chuck 20.

The electrostatic chuck 20 can be driven in the vertical direction. As shown in FIG. 1, the electrostatic chuck 20 is driven up and down inside the chamber by using an electrostatic chuck drive unit 22 disposed above the vacuum chamber 10. By driving the electrostatic chuck 20 up and down as described above, it is advantageous to secure a minimum space for generating the side plasma and the back plasma.

On the surface of the electrostatic chuck 20, a circuit pattern protective layer (not shown) is formed of a material having a hardness smaller than the hardness of a circuit pattern formed on the substrate surface, in order to protect circuit patterns formed on the substrate surface. May be further included. The circuit pattern protective layer may be formed on all or a part of the electrostatic chuck that contacts the upper surface of the substrate, and may be made of a material such as polyimide film.

Further, the electrostatic chuck 20 may further include an insulating member for protecting the exposed portion, that is, the side surface, the stepped surface, and the like. As shown in FIG. 1, the exposed portion of the electrostatic chuck 20 may be damaged by plasma, so that an insulating member is separately formed and protected.

Next, the transfer chuck 30 is a component disposed below the vacuum chamber 10 and drivable in the vertical direction. The moving chuck 30 is disposed in parallel with the above-described electrostatic chuck 20 and is arranged to be vertically drivable by a moving chuck driving part 32 provided at the lower part of the chamber, as shown in Fig. By moving the transfer chuck 30 up and down, a proper space for formation of the back surface plasma can be ensured. Of course, when the electrostatic chuck 20 has a structure capable of driving up and down, the moving chuck 30 may not be driven up and down.

Next, the upper insulator 40 is a component disposed on the side of the electrostatic chuck 20 at a predetermined distance from the side surface of the electrostatic chuck. As shown in FIG. 2, the upper insulator 40 is disposed opposite to and spaced apart from the side surface of the electrostatic chuck 20, and provides a space for side plasma formation for edge cleaning of the substrate. The upper insulator 40 has a ring shape as a whole. On the other hand, the upper insulator 40 may be further provided with an auxiliary insulator surrounding itself.

The substrate holder 50 is disposed on the side of the transfer chuck 30 and surrounds the substrate so that the lower surface and the side surface of the substrate W fixed to the electrostatic chuck 20 are exposed. 1 and 2, the substrate holder 50 is disposed in contact with the side surface of the transfer chuck 30 so that the substrate W is held on the side surface of the substrate with the substrate W gripped by the electrostatic chuck 20, And covers the lower surface and the side surface of the substrate so that the lower surface and the lower surface are exposed. The substrate holder 50 approaches the above-described upper insulator 40 and forms a space for forming the side plasma together with the upper insulator.

As shown in FIGS. 1 and 2, the substrate holder 50 may be formed so that a portion of the substrate holder 50 facing the side surface of the substrate W has a smooth curved surface or a chamfered surface. It may also be made of a generally angled edge. This is for adjusting the plasma sheath shape for edge cleaning of the substrate, and the shape of the substrate holder 50 may be variously changed. Thus, by changing the shape of the substrate holder 50, the etching rate of the edge portion of the substrate W can be changed.

Next, the lower insulator 60 is disposed outside the substrate holder 50, as shown in FIGS. 1 and 2, and is a component opposed to the upper insulator 40. This lower insulator 60 adheres to the upper insulator 50 during the substrate cleaning process to help stably form the side plasma.

The upper gas supply path 70 is formed in the electrostatic chuck 20 to supply a process gas to a space between the side surface of the electrostatic chuck 20 and the upper insulator 40. The upper gas supply path 70 is formed through the inside of the electrostatic chuck 20 as shown in FIGS. 1 and 2. The end of the upper gas supply path 70 is a space between the upper insulator 40 and the electrostatic chuck 20 . Accordingly, the process gas supplied from the outside is supplied to the space between the side surface of the electrostatic chuck 20 and the upper insulator 40 so that the side plasma is generated. One end of the upper gas supply path 70 is connected to an external process gas supply source 62, as shown in FIG.

The lower gas supply path 80 is a component formed in the transfer chuck 30 and supplies the process gas to a space between the substrate W and the transfer chuck 30. [ 1, the lower gas supply path 80 is formed through the transfer chuck 30 and supplies a process gas to a space between the substrate W and the transfer chuck 30, The back-side plasma for etching the back surface of the substrate is formed by the process gas thus supplied. Of course, as shown in FIG. 1, a lower gas supply path 80 may also be formed in the substrate holder 50 to supply the process gas to the side plasma forming space. One end of the lower gas supply path 80 is connected to a process gas supply source 82 provided outside and receives a process gas.

Meanwhile, the lower gas supply path 80 may have a multi-layer structure as shown in FIG. In the case of such a multilayer structure, the process gas is uniformly diffused through each layer, and the process gas can be uniformly supplied toward the substrate.

Next, the RF applying means 90 is connected to the electrostatic chuck 20 to apply RF power, as shown in FIG. Although FIG. 1 shows that the RF applying means 90 is connected to the electrostatic chuck 20, the RF applying means may be connected to the moving chuck to apply RF power to the moving chuck. When the RF power is applied to the electrostatic chuck, the mobile chuck is grounded, and when the RF power is applied to the mobile chuck, the electrostatic chuck is grounded.

The substrate cleaning apparatus 1 according to the present embodiment may further include a lift pin 100. 1, the lift pin 100 is formed to penetrate through the moving chuck 30 and is vertically driven to receive a substrate loaded from the outside. The lift pins 100 are connected to the lift pin assembly 102 and are simultaneously driven so that during the loading of the substrate W into the vacuum chamber 10, And receives the substrate from the end effector. Then, the substrate W is transferred to the electrostatic chuck 20.

In the process of unloading the substrate, the lower portion of the substrate W gripped by the electrostatic chuck 20 is supported, and the substrate is transferred from the electrostatic chuck. Then, the substrate is transferred to the end effector that enters through the substrate entrance 12. Therefore, the loading unloading process of the substrate smoothly proceeds by the lift pins 100.

In addition, an upper cooling channel (24) may be further formed in the electrostatic chuck (20). 1, the upper cooling channel 24 is formed inside the electrostatic chuck 20 so that the cooling medium is circulated and a function of cooling the substrate W gripped on the electrostatic chuck in the process progress is provided do.

Likewise, the moving chuck 30 may further include a lower cooling channel 34 for cooling the moving chuck by circulating the cooling medium. The lower cooling channel 34 functions to cool the moving chuck 30 heated by plasma during the process.

Next, a baffle 110 may be further provided between the lower insulator 60 and the side wall of the vacuum chamber 10. The baffle 110 serves to uniformize the flow of the process gas or the like discharged to the gas discharge port 16 formed under the vacuum chamber 10 to increase the process uniformity. The baffle 110 may be arranged to be vertically drivable for completeness of the process. This is because the process conditions can be changed by adjusting the height of the baffle 110.

Hereinafter, a process of simultaneously cleaning the side surface and the bottom surface of the substrate using the substrate cleaning apparatus 1 according to the present embodiment will be described.

First, the substrate is transferred into the vacuum chamber 10 using the end effector. The lift pin 100 then rises to receive the substrate from the end effector. Then, when the end effector is retracted out of the vacuum chamber, the gate valve 14 is closed and the pressure inside the chamber is adjusted to the process conditions.

Thereafter, the lift pins 100 are raised or the electrostatic chuck 20 is lowered so that the electrostatic chuck 20 and the substrate W are brought into contact with each other, and DC power is applied to the electrostatic chuck 20 to generate electrostatic force . Then, the substrate is fixed to the electrostatic chuck by electrostatic force. When the substrate is fixed to the electrostatic chuck 20, the lift pin 100 is lowered.

The distance between the electrostatic chuck 20 and the moving chuck 30 is adjusted so that a space suitable for generating plasma is formed on the side and back side of the substrate while the substrate W is gripped on the electrostatic chuck 20. [ Then, the process gas is supplied to the side surface and back side of the substrate through the upper gas supply path 70 and the lower gas supply path 80. When the RF power is applied to the electrostatic chuck 20 in this state, the side plasma P1 and the rear plasma P2 are generated as shown in FIG. 3, so that the side surface and the back surface of the substrate are simultaneously cleaned.

Here, the side plasma P1 is a plasma formed in the space formed by the side surface of the electrostatic chuck 20, the upper insulator 40, and the substrate holder 50, as shown in Fig. 3, The side surface and the edge portion of the substrate W are cleaned by the cleaning tool P1.

The rear plasma P2 is a plasma formed in the space between the back surface of the substrate W and the moving chuck 30 as shown in Fig. The back surface is cleaned.

When the cleaning process is completed, the substrate is taken out of the vacuum chamber in the reverse order of the substrate carry-in described above.

1 is a cross-sectional view showing a structure of a substrate cleaning apparatus according to an embodiment of the present invention.

2 is a partially enlarged view of a substrate cleaning apparatus according to an embodiment of the present invention.

3 is a state in which a plasma is generated in a substrate cleaning apparatus according to an embodiment of the present invention.

4 is a cross-sectional view showing a structure of a transfer chuck according to an embodiment of the present invention.

Claims (9)

Plasma is generated on the side surfaces and the lower surface of the substrate while the upper surface of the substrate is gripped to clean the lower surface and the side surface of the substrate, The substrate cleaning apparatus includes: A vacuum chamber capable of maintaining the inside thereof in a vacuum state; An electrostatic chuck disposed on the upper side of the vacuum chamber and fixing the substrate in contact with the upper surface of the substrate so that the substrate edge is exposed; A moving chuck disposed below the inside of the vacuum chamber and drivable in a vertical direction; An upper insulator disposed on a side of the electrostatic chuck at a predetermined distance from a side surface of the electrostatic chuck; A substrate holder disposed on a side of the transfer chuck and surrounding the substrate such that a lower surface and a side surface of the substrate fixed to the electrostatic chuck are exposed; A lower insulator disposed outside the substrate holder and facing the upper insulator; An upper gas supply path formed in the electrostatic chuck for supplying a process gas to a space between the side surface of the electrostatic chuck and the upper insulator; A lower gas supply path formed on the transfer chuck to supply a process gas to a space between the substrate and the transfer chuck; And RF applying means for applying RF power to the electrostatic chuck or the moving chuck. delete The method according to claim 1, Further comprising a lift pin formed to penetrate the moving chuck and driven in a vertical direction to receive a substrate loaded from the outside. The electrostatic chuck according to claim 1, Wherein the side surface is formed to be stepped by the thickness of the upper insulator so that the electrostatic chuck, the upper insulator, the substrate holder, and the lower insulator are closely contacted to form a donut-shaped space. The method according to claim 1, Wherein the electrostatic chuck is further provided with an upper cooling channel for cooling the electrostatic chuck by circulating the cooling medium. The method according to claim 1, Further comprising a lower cooling channel for cooling the moving chuck by circulating the cooling medium in the moving chuck. The method according to claim 1, Wherein the electrostatic chuck is arranged so as to be able to be driven in the vertical direction. The method according to claim 1, Wherein a baffle is further provided between the lower insulator and the side wall of the vacuum chamber. 9. The method of claim 8, Wherein the baffle is disposed so as to be able to be driven in the vertical direction.

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