TW201724167A - Plasma processing device capable of improving magnetic shielding effect - Google Patents

Abstract

The present invention provides a plasma processing device for improving magnetic shielding effect. The plasma processing device includes a reaction chamber including a processing space therein; a base provided in the reaction chamber for placing a substrate; a plasma generating unit for exciting gas in the processing space into plasma; a magnetic shielding member located at a periphery of the processing space and including at least two magnetic shielding layers isolated from each other.

Description

Plasma processing device

The present invention relates to a plasma processing apparatus for processing a semiconductor element, such as a plasma etching apparatus, a plasma deposition apparatus, or the like.

In order to improve the consistency of processing of a plasma processing apparatus (such as a plasma etching apparatus), it is necessary to eliminate or suppress interference of an external magnetic field such as geomagnetism with plasma. The current mainstream solution is to cover the outside of the reaction chamber of the plasma processing apparatus with a layer of high permeability metal plate or layer to achieve a magnetic mask inside the reaction chamber. Specific technical details can be found in U.S. Patent Application Publication No. US 2007/0062449 A1, issued March 22, 2007.

However, this technology still mainly has the following problems: to achieve a magnetic mask effect of more than 90% with a single-layer magnetic mask layer, it is necessary to use a high magnetic permeability material (relative magnetic permeability usually needs to be greater than 10000), and also The magnetic mask layer has a large thickness (typically requiring more than 2 mm) and a tight seal. Due to the high price of high permeability materials, further increase in thickness can increase the magnetic mask effect, but the cost increases rapidly.

According to an aspect of the invention, there is provided a plasma processing apparatus comprising: a reaction chamber internally provided with a processing space; a susceptor disposed in the reaction chamber for placing a substrate; and a plasma generating unit for processing the space The gas inside dissociates into a plasma; a magnetic mask member, located at the periphery of the processing space, includes at least two magnetic mask layers that are isolated from each other.

Preferably, the magnetic mask comprises a side wall and a lining of the reaction chamber which are separated from each other, the lining is located in the reaction chamber and surrounds the processing space, at least one magnetic mask layer is disposed on the side wall of the reaction chamber, and at least one magnetic mask layer is disposed In the lining.

Preferably, the magnetic mask layer is disposed on the inner surface, the outer surface or the inner side of the side wall of the reaction chamber; the magnetic mask layer is disposed on the inner surface, the outer surface or the inner portion of the inner liner.

Preferably, the magnetic mask layer is disposed in an interlayer manner on the sidewall of the reaction chamber or inside the liner.

Preferably, the magnetic mask comprises a side wall of the reaction chamber, and the magnetic mask layer is disposed on the inner surface, the outer surface or the inner side of the side wall of the reaction chamber.

Preferably, the magnetic mask comprises an inner liner, the inner liner is located in the reaction chamber and surrounds the processing space, and the magnetic mask layer is disposed on the inner surface, the outer surface or the inner portion of the inner liner.

Preferably, the medium used to isolate adjacent magnetic mask layers comprises a conductor, a semiconductor, an insulator, air or a vacuum.

Preferably, the spacing between adjacent magnetic mask layers is greater than the thickness of each of the two magnetic mask layers.

Preferably, the plasma generating unit includes an opposite upper electrode, a lower electrode, and a radio frequency source connected to at least one of the upper electrode and the lower electrode.

Preferably, the plasma generating unit comprises a coupling coil disposed above the top wall of the reaction chamber and a radio frequency source connected to the coupling coil.

According to another aspect of the present invention, there is provided a plasma processing apparatus comprising: a reaction chamber internally provided with a processing space; a plasma generating unit for dissociating a gas in the processing space into a plasma; and a metal casing disposed in the reaction The periphery of the cavity is spaced apart from the reaction chamber; the magnetic mask member is located at the periphery of the processing space and includes at least two magnetic mask layers separated from each other.

Preferably, the metal casing is provided with a magnetic mask layer.

Preferably, the inner surface, the outer surface or the inner portion of the metal casing is provided with a magnetic mask layer.

Preferably, the magnetic mask layer of the magnetic mask is disposed on the metal casing, the reaction chamber wall or the inner liner, and the inner liner is located in the reaction chamber and surrounds the processing space.

Hereinafter, the plasma processing apparatus of the present invention will be described with reference to the embodiments and the drawings. It is emphasized that the description herein is merely exemplary and that other embodiments that utilize the invention are not excluded.

Fig. 1 is a schematic structural view of a plasma processing apparatus according to an embodiment of the present invention. In this embodiment, it is an inductively coupled plasma (ICP) processing device. As shown in Fig. 1, the plasma processing apparatus includes a reaction chamber 2 surrounded by a plurality of walls (a side wall 21, a top wall 23, and a bottom wall 25), and a processing space 20 is provided inside the reaction chamber 2. A susceptor 3 for placing the substrate W is disposed in the reaction chamber 2 and located below the processing space 20. A plasma generating unit for dissociating gas within the processing space 20 into a plasma includes a coupling coil 42 disposed above the top wall 23 of the reaction chamber, and an RF source coupled to the coupling coil 42 for providing power to the coupling coil 42. 44. The formed plasma can process the substrate W.

A magnetic mask is disposed around the processing space 20 to eliminate or attenuate interference of an external magnetic field with the plasma in the reaction chamber 2. To improve the masking effect of the magnetic masking material, the magnetic masking member includes at least two magnetic mask layers 8 that are isolated from each other. The magnetic mask layer here should be understood in a broad sense, which can be a coating applied or sputtered on the surface of the object (the coating cannot be detached or removed from the surface of the object, otherwise the coating will be damaged), or It is a magnetic mask that is pre-formed by a magnetic mask material (which can be mounted or fixed on the surface of an object or inside an object, or can be detached or removed from the object). In addition, the medium for isolating adjacent magnetic mask layers (or materials located between adjacent magnetic mask layers) may be a conductor, a semiconductor, an insulator, air or vacuum, or the like. Experiments have shown that no matter which of the above materials is between the two magnetic mask layers, the magnetic mask effect can be greatly improved.

In the embodiment illustrated in Figure 1, the magnetic shield comprises opposing reaction chamber sidewalls 21 and liner 6 that are isolated from one another. The reaction chamber side wall 21 is substantially parallel to the inner liner 6, or both extend generally in the same direction (vertical direction). The liner 6 is located within the reaction chamber 2 and surrounds (or defines) the processing space 20. The inner liner 6 may be cylindrical or cylindrical in shape such that the distribution of the plasma in all directions is as uniform as possible. The liner 6 is usually easily replaceable. During the processing, plasma or other particles inevitably form a deposited film on the surface of the liner 6, which is too thick, which will seriously affect the consistency of plasma processing. Thus, the liner 6 is usually replaced at regular intervals.

To create a magnetic masking effect, the reaction chamber sidewall 21 is provided with at least one magnetic mask layer 8, and the inner liner 6 is provided with at least one magnetic mask layer 8. There are a plurality of ways in which the magnetic mask layer 8 is provided. For example, the magnetic mask layer 8 may be disposed on the inner surface of the reaction chamber side wall 21 (or the inner liner 6), or may be disposed on the outer surface of the reaction chamber side wall 21 (or the inner liner 6). In addition, the magnetic mask layer 8 may be disposed inside the reaction chamber side wall 21 (or the inner liner 6). For example, a void may be dug inside the reaction chamber side wall 21 (or the inner liner 6) and a plate made of a magnetic mask material may be inserted into the gap.

In general, the more layers of the phase-isolated magnetic mask layer, the better the effect of the magnetic mask. In the present embodiment, the inner and outer surfaces and the inner portion of the reaction chamber side wall 21, the inner and outer surfaces of the inner liner 6, and the inner portion thereof are provided with a magnetic mask layer 8. However, in general, as long as there are two mask layers that are isolated, the mask effect can be substantially satisfied. Thus, in other embodiments, the number of magnetic mask layers can be two, three, four, five, or seven, and the like. Alternatively, it is also possible to provide the magnetic mask layer 8 only on the reaction chamber side wall 21 without the liner 6, or only the inner liner 6 and not on the reaction chamber side wall 21. When the magnetic mask layer 8 is disposed on the inner surface of the reaction chamber side wall 21 or the inner surface and the outer surface of the inner liner 6, which are often exposed to plasma, a resist layer may be disposed on the surface of the magnetic mask layer 8, such as A layer of ruthenium oxide or the like to prevent the magnetic mask layer from being corroded by the plasma.

The inventors have further discovered that when the spacing between adjacent two magnetic mask layers (referring to the distance between their adjacent surfaces) is greater than the thickness of each of the two magnetic mask layers, the magnetic mask The effect will also be significantly better. Therefore, in actual implementation, the spacing of adjacent magnetic mask layers can be set according to this principle.

For the inductively coupled plasma processing apparatus as described above, the magnetic shield layer is generally not disposed except for the top wall 23 of the reaction chamber (since the magnetic field generated by the coupling coil 42 enters the reaction chamber 2 through the top wall 23, the top wall In addition to the nature of the magnetic mask, the other walls (side wall 21, bottom wall 25) may be provided with an isolated magnetic mask layer 8 to enhance the magnetic mask effect.

Fig. 2 is a view showing the configuration of a plasma processing apparatus according to another embodiment of the present invention. In this embodiment, it is a capacitively coupled plasma (CCP) processing device. It differs from the embodiment of Fig. 1 only in the plasma generating unit and the top wall 23. For the description of the same structure, reference may be made to the description of the embodiment of Fig. 1, which will not be described later. The following only describes the differences between the two.

As shown in Fig. 2, the plasma generating unit includes a relatively disposed upper electrode 232, a lower electrode (the lower electrode is a part of the susceptor 3), and a radio frequency source (not shown) connected to at least one of the upper and lower electrodes. Since the top wall 23 is no longer necessary to have magnetic permeability, the top wall 23 in this embodiment can be provided with the magnetic mask layer 8.

In addition, the plasma processing apparatus of each of the above embodiments may further include a metal casing (not shown) disposed at the periphery of the reaction chamber 2 and spaced apart from the reaction chamber 2 (or two). There is a gap between the people). To improve the magnetic masking effect, the metal casing may be provided with a magnetic mask layer as described above. The manner in which the magnetic mask layer is disposed is not limited. It may be disposed on the inner surface and the outer surface of the metal outer casing, or may be disposed inside the metal outer casing, or may be disposed at any two places or at any two of them or Multiple places.

Figure 3 is a schematic illustration of the magnetic masking effect of a single layer magnetic mask layer. A schematic view of the structure to be tested is shown in (a) of Fig. 3, and the magnetic mask layer has a single layer structure (i.e., only one magnetic mask layer from the external magnetic field to the magnetic mask region). The material of the magnetic mask layer is permalloy 1J85. An external, constant vertical magnetic field passes through the magnetic mask layer from above into the magnetic mask region. The magnetic mask effect of the magnetic mask layer can be measured by measuring the magnetic field strength of the magnetic mask region. (b) of Fig. 3 shows the corresponding test results. When the thickness of the magnetic mask layer is 0.2 mm (mm), the measured magnetic field strength is about 0.5 Gauss (Gauss); when the thickness of the magnetic mask layer is increased to 1.0 mm (mm), the measured magnetic field strength is reduced to about 0.2 Gauss. (Gauss).

Figure 4 is a schematic illustration of the magnetic mask effect of a two-layer magnetic mask layer. A schematic view of the structure to be tested is shown in (a) of Fig. 4, and the magnetic mask layer has a two-layer structure (i.e., two magnetic mask layers separated from each other from the external magnetic field to the magnetic mask region). The material of the two-layer magnetic mask layer is also permalloy 1J85. The thickness of each layer of the magnetic mask layer is maintained at 0.5 millimeters (mm), and the total thickness of the two layers is 1 millimeter (mm). The medium between the two magnetic mask layers is air (or air interlayer). An external, constant vertical magnetic field (the intensity of which is the same as in Figure 3) passes through the double layer magnetic mask layer from above into the magnetic mask region. The magnetic mask effect of the double-layer magnetic mask layer can be measured by measuring the magnetic field strength of the magnetic mask region. (b) of Fig. 4 shows the corresponding test results. When the thickness of the air interlayer is 1 millimeter (mm), the measured magnetic field strength is about 0.15 Gauss. When the thickness of the air interlayer is increased to 8 mm (mm), the measured magnetic field strength is reduced to about 0.05 Gauss (Gauss) - which is much smaller than the 0.2 Gauss (Gauss) of the same thickness single-layer magnetic mask layer in Figure 3. That is, the magnetic mask effect is improved by 75%.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the description Various modifications and alterations of the present invention will be apparent to those skilled in the <RTIgt; Therefore, the scope of the invention should be limited by the scope of the appended claims.

2‧‧‧Reaction chamber
20‧‧‧Processing space
21‧‧‧ side wall
23‧‧‧ top wall
232‧‧‧Upper electrode
25‧‧‧ bottom wall
3‧‧‧Base
42‧‧‧Coupling coil
44‧‧‧RF source
6‧‧‧ lining
8‧‧‧Magnetic mask
W‧‧‧ substrates

Fig. 1 is a schematic structural view of a plasma processing apparatus according to an embodiment of the present invention. Fig. 2 is a view showing the configuration of a plasma processing apparatus according to another embodiment of the present invention. Figure 3 is a schematic illustration of the magnetic masking effect of a single layer magnetic mask layer. Figure 4 is a schematic illustration of the magnetic masking effect of a two-layer magnetic mask layer.

2‧‧‧Reaction chamber

20‧‧‧Processing space

21‧‧‧ side wall

23‧‧‧ top wall

25‧‧‧ bottom wall

3‧‧‧Base

42‧‧‧Coupling coil

44‧‧‧RF source

6‧‧‧ lining

8‧‧‧Magnetic mask

W‧‧‧ substrates

Claims (14)

A plasma processing apparatus comprising: a reaction chamber internally provided with a processing space; a susceptor disposed in the reaction chamber for placing a substrate; and a plasma generating unit for dissociating the gas in the processing space into a plasma And a magnetic mask member located at a periphery of the processing space, including at least two magnetic mask layers separated from each other. The plasma processing apparatus of claim 1, wherein the magnetic mask comprises sidewalls and a liner of the reaction chamber isolated from each other, the liner being located in the reaction chamber and surrounding the processing space, at least one The magnetic mask layer is disposed on the sidewall of the reaction chamber, and at least one of the magnetic mask layers is disposed on the liner. The plasma processing apparatus of claim 2, wherein the magnetic mask layer is disposed on an inner surface, an outer surface or an inner side of the side wall of the reaction chamber; the magnetic mask layer is disposed on an inner surface of the inner liner, Outer surface or interior. The plasma processing apparatus of claim 3, wherein the magnetic mask layer is disposed in an interlayer manner on a sidewall of the reaction chamber or inside the liner. The plasma processing apparatus of claim 1, wherein the magnetic mask comprises a reaction chamber sidewall disposed on an inner surface, an outer surface or an inner portion of the reaction chamber sidewall. The plasma processing apparatus of claim 1, wherein the magnetic mask comprises an inner liner, the inner liner is located in the reaction chamber, and surrounds the processing space, and the magnetic mask layer is disposed on the inner liner. Inner surface, outer surface or interior. The plasma processing apparatus of claim 1, wherein the medium for isolating the adjacent magnetic mask layer comprises a conductor, a semiconductor, an insulator, air or a vacuum. The plasma processing apparatus of claim 1, wherein a spacing between two adjacent magnetic mask layers is greater than a thickness of each of the two magnetic mask layers. The plasma processing apparatus of claim 1, wherein the plasma generating unit comprises an opposite upper electrode, a lower electrode, and a radio frequency source connected to at least one of the upper electrode and the lower electrode. The plasma processing apparatus of claim 1, wherein the plasma generating unit comprises a coupling coil disposed above a top wall of the reaction chamber, and a radio frequency source connected to the coupling coil. A plasma processing apparatus comprising: a reaction chamber internally provided with a processing space; a plasma generating unit for dissociating the gas in the processing space into a plasma; and a metal casing disposed at a periphery of the reaction chamber and The reaction chambers are separated by a distance; and a magnetic mask member is located at the periphery of the processing space and includes at least two magnetic mask layers that are isolated from each other. The plasma processing apparatus of claim 11, wherein the metal casing is provided with the magnetic mask layer. The plasma processing apparatus of claim 11, wherein the inner surface, the outer surface or the inner portion of the metal casing is provided with the magnetic mask layer. The plasma processing apparatus of claim 11, wherein the magnetic mask layer of the magnetic mask is disposed on the metal casing, the reaction chamber wall or the inner liner, and the liner is located in the reaction chamber. And surround the processing space.