KR101237400B1 - plasma etching apparatus - Google Patents

Abstract

The plasma etching apparatus consists of a housing and a plasma source portion. The housing provides a process space in which the substrate is processed, and the substrate is inserted therein. The plasma source unit includes a first electrode unit installed on an outer wall of the housing and receiving a voltage from the outside, and at least one magnet unit provided on one side of the first electrode unit. The magnet unit forms a magnetic field inside the housing. Accordingly, the plasma etching apparatus can form a uniform high density plasma and improve the etching uniformity of the substrate.

Description

Plasma etching apparatus

The present invention relates to an apparatus for manufacturing a semiconductor substrate, and more particularly, to a plasma etching apparatus and method for etching a thin film formed on a semiconductor substrate using a plasma.

In general, plasma refers to an ionized gas state composed of ions, electrons, radicals, and the like, and is generated by a very high temperature, strong electric fields, or high frequency electromagnetic fields.

Particularly, plasma generation by glow discharge is performed by free electrons excited by direct current or high frequency electromagnetic field, and the excited free electrons collide with gas molecules to generate active species such as ions, radicals and electrons. ) These active species physically or chemically act on the surface of the material to change the surface properties. As such, treating the surface of a substance with active species is referred to as plasma treatment.

Plasma etching apparatuses for manufacturing semiconductor devices using plasma include capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) methods. The capacitively coupled plasma method has a low plasma density, and thus, when applied to a process of etching a semiconductor device, it is difficult to obtain a high etching rate. On the other hand, the inductively coupled plasma method has a low etching selectivity and may damage the semiconductor device due to the plasma.

An object of the present invention is to provide a plasma etching apparatus that can improve the etching efficiency.

It is also an object of the present invention to provide a method for etching a substrate using the plasma etching apparatus described above.

Plasma etching apparatus according to one feature for realizing the above object of the present invention comprises a housing, a substrate support member, and a plasma source portion.

The housing provides a process space in which the substrate is processed, has at least one gas inlet through which a process gas is introduced, and has a plasma space in which a plasma for etching the substrate is formed. A substrate supporting member is installed inside the chamber, and the substrate is seated and grounded. The plasma source unit includes a first electrode unit installed on an outer wall of the housing to receive a voltage from the outside, and at least one magnet unit installed on one side of the first electrode unit to form a magnetic field inside the housing. Gas is used to generate the plasma.

In addition, the substrate processing method according to one feature for realizing the object of the present invention, after forming a plasma using a process gas on the upper portion of the substrate introduced into the housing, and then providing the plasma to the substrate The substrate is etched. The substrate is supported by a grounded substrate support member provided inside the housing. The plasma is formed by an electromagnetic field formed inside the housing by the first electrode portion provided on the outer wall of the housing and the substrate supporting member, and inside the housing by at least one magnet unit provided on one side of the first electrode portion. The collision of electrons is increased by the magnetic field to be formed uniformly.

According to the present invention described above, in the plasma etching apparatus, by providing a magnet unit outside the first electrode part, a plasma of high density can be formed and the etching uniformity of the substrate can be improved.

1 is a view schematically showing a plasma etching apparatus of the present invention.
FIG. 2 is a plan view of the gas plate illustrated in FIG. 1. FIG.
3 is a cross-sectional view taken along the line II ′ of FIG. 1.
4 is a perspective view illustrating the first electrode unit and the first and second magnet units illustrated in FIG. 1.
5 is a perspective view illustrating the first magnet illustrated in FIG. 4.
FIG. 6 is a diagram illustrating a process of etching a substrate in the plasma etching apparatus of FIG. 1.
7 is a diagram illustrating a plasma etching apparatus according to another embodiment of the present invention.
8 is a view showing a plasma etching apparatus according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. For reference, the plasma etching apparatus to be described later may be used in an insulating layer spacer etching process such as SiN and SiO 2 or a SiN mask etching process of a gate line and a bit line.

1 is a schematic view showing a plasma etching apparatus of the present invention, Figure 2 is a plan view showing a gas plate shown in FIG.

1 and 2, the plasma etching apparatus 101 of the present invention performs a semiconductor process for processing a substrate. Hereinafter, an etching process of etching the thin film formed on the substrate by the semiconductor process will be described as an example.

The plasma etching apparatus 101 may include a chamber 110, a chuck 120, an exhaust pipe 130, a lead 140, a gas supply line 150, and a plasma source unit.

In detail, the chamber 110 provides a process space in which the etching process is performed. The chamber 110 may have an open top and include a bottom surface 111 and sidewalls 112 extending vertically from the bottom surface 111 to form the process space. In one example of the present invention, the chamber 110 has a generally circular columnar shape, and an inner wall thereof is coated with an insulating material such as iridium or alumina. An exhaust port 111a is formed in the bottom surface 111 of the chamber 110, and the exhaust port 111a communicates with the exhaust pipe 130 provided below the bottom surface 111. The reaction by-products and gases formed in the process space during the etching process are discharged to the outside through the exhaust port 111a and the exhaust pipe 130.

The chuck 120 is installed inside the chamber 110. The chuck 120 is a support member for supporting the substrate, and fixes the substrate during the etching process. The chuck 120 may include a grounded support plate 121 on which the substrate is mounted, and a support shaft 122 coupled below the support plate 121. The support shaft 122 is basically not rotated, but may be installed to be rotatable about the central axis, and the support plate 121 is rotated by the rotation of the support shaft 122. In one example of the invention, the chuck 120 may be an electrostatic chuck 120.

The lid 140 is installed above the chamber 110. The lid 140 is coupled to face the chamber 110 and provides a plasma space PGS in which plasma for the etching process is formed. The lead 140 is made of an insulating material, for example, ceramic or quartz. In this embodiment, the chamber 110 and the lid 140 are combined with each other to form a housing.

In an example of the present invention, the lid 140 includes an upper surface 141 facing the support plate 121, a side wall 142 extending perpendicular to the upper surface 141, and the upper surface 141 and the side wall ( It may include a connecting portion for connecting the 142. In detail, a gas inlet 141a through which the process gas for forming the plasma is introduced is formed at the center of the upper surface 141 of the lid 140. In this embodiment, the process gas may include nitrogen and oxygen.

In this embodiment, the shape of the lead 140 is similar to the circular column shape, but may be formed in a dome shape, in which case, the gas inlet 141a is a gas plate 143 shown in FIG. It is formed in the center of the lead 140 in the form of a gas hole (143a) of the () or injection hole of the shower head.

The side wall 142 of the lid 140 extends vertically downward from the top surface 141 to form a plasma space PGS inside the lid 140. The connection part is made of a curved surface and connects the side wall 142 and the upper surface 141.

The gas plate 143 is fixedly installed in the lid 140. The gas plate 143 is disposed below the upper surface 141 of the lid 140 to face the upper surface 141, and is spaced apart from the upper surface 141, and made of an insulating material, for example, quartz or ceramic material. In one example of the present invention, the gas plate 143 has a generally disc shape and has an area equal to or larger than the upper surface of the support plate 121. The process gas is introduced into the space 141b in which the upper surface 141 of the lid 140 and the gas plate 143 are spaced apart from each other through the gas inlet 141a.

A plurality of gas holes 143a are formed in the periphery of the gas plate 143, and the plurality of gas holes 143a are continuously disposed along the periphery of the gas plate 143. Here, the arrangement of the gas holes 143a may be formed in various forms in order to improve the uniformity of the deposited film quality, and a general shower head structure is also possible. The gas inlet 141a formed on the upper surface 141 of the lid 140 is positioned to face the central portion of the gas plate 143. In this embodiment, the gas plate 143 has a gas hole at the central portion of the gas plate 143 in order to prevent the process gas introduced through the gas inlet 141a from being concentrated to the central portion of the support plate 121. 143a is not formed.

On the other hand, a gas supply line 150 for providing the process gas is installed on the lead 140, the gas supply line 150 is in communication with the gas inlet (141a). Accordingly, the process gas flows from the gas supply line 150 into the space 141b between the upper surface 141 of the lid 140 and the gas plate 143 through the gas inlet 141a. The process gas is uniformly dispersed in the separation space 141b and then flows into the plasma space PGS through the plurality of gas holes 143a.

3 is a cross-sectional view taken along the line II ′ of FIG. 1, FIG. 4 is a perspective view illustrating the first electrode part and the first and second magnet units shown in FIG. 1, and FIG. 5 is shown in FIG. 4. A perspective view showing a first magnet.

1 and 3, the sidewall 142 of the lid 140 is provided with a plasma source portion for forming the plasma in the plasma space PGS. In this embodiment, the plasma source unit generates a plasma in a capacitively coupled plasma (CCP) method that discharges by applying a voltage to the electrode. The plasma source unit may include first and second electrode units 161 and 162, a first RF generator 170, and first and second magnet units 181 and 182.

Specifically, the first electrode part 161 is provided on the outer surface of the side wall 142 of the lead 140 and has a ring shape surrounding the side wall 142 of the lead 140. In this embodiment, the first electrode part 161 covers the entire outer surface of the sidewall 142 of the lead 140.

The first electrode unit 161 is connected to the first RF generator 170. The first RF generator 170 outputs RF power to the first electrode unit 161, whereby an electromagnetic field is formed in the plasma space PGS by the first electrode unit 161 and the chuck 120. do. The first RF generator 170 outputs a high frequency power source to form a high density electromagnetic field in the plasma space PGS. The first RF generator 170 uses a frequency of 13.56 MHz, but may be a high frequency of about 160 MHz to about 400 MHz to 60 MHz, and may use a microwave of 2.45 Hz. The frequency of the first RF generator 170 can be appropriately selected according to the type of process gas used for the substrate processing and the pressure during the process. The process gas introduced into the plasma space PGS through the gas plate 143 forms a plasma by the electromagnetic field.

Although not shown in the drawing, the first RF generator 170 is connected to a matching box that adjusts the intensity of the power output from the first RF generator 170, and is output from the first RF generator 170. Power is provided to the first electrode unit 161 through the matching box.

Since the first electrode part 161 is installed on the sidewall 142 of the lead 140, the first electrode part 161 is formed in the plasma space PGS by the chuck 120 and the first electrode part 161 installed in the chamber 110. As the intensity of the electromagnetic field moves away from the sidewall 142 of the lead 140, the strength of the electromagnetic field may decrease. That is, the strength of the electromagnetic field formed in the center of the plasma space PGS may be weaker than that in other areas.

In order to compensate for these disadvantages, the second electrode part 162 is installed at the connection part to which the upper surface 141 and the side wall 142 of the lead 140 are connected to improve the plasma uniformity in the chamber 110. The intensity of the electromagnetic field at the center of the plasma space PGS is prevented from decreasing. The second electrode part 162 is spaced apart from the first electrode part 162 and has a shape corresponding to the connection part, that is, a curved surface, and has a ring shape surrounding the lead 140. The second electrode unit 162 receives RF power from the first RF generator 170 similarly to the first electrode unit 161. Accordingly, an electromagnetic field of uniform intensity may be formed in the inner space of the lead 140 by the first and second electrode parts 161 and 162 and the chuck 120.

In this embodiment, the plasma source portion includes two electrode portions 161 and 162, but may include only the first electrode portion 161. A structure having only the first electrode portion 161 will be described in detail later with reference to FIG. 8.

Meanwhile, first and second magnet units 181 and 182 are attached to the outer side of the first electrode part 161. The first and second magnet units 181 and 182 are spaced apart from each other vertically and surround the first electrode part 161, respectively. An upper end of the first magnet unit 181 is coupled to an upper end of the first electrode unit 161, and a lower end of the second magnet unit 182 is coupled to a lower end of the first electrode unit 161. In this embodiment, the plasma etching apparatus 101 includes two magnet units 181 and 182, but the number of magnet units 181 and 182 may increase or decrease depending on the process efficiency.

When the plasma is formed, a magnetic field is formed between the first and second magnet units 181 and 182 by the first and second magnet units 181 and 182 in the plasma space PGS, and within the plasma space PGS. Electrons collide with each other by changing their direction of travel under the influence of the magnetic fields formed by the first and second magnet units 181 and 182. Accordingly, in the plasma etching apparatus 101, since the high density uniform plasma is formed in the plasma space PGS, the etching uniformity of the substrate may be improved. As such, since the plasma etching apparatus 101 may improve the uniformity of plasma through the first and second magnet units 161 and 162, separate showers having a plurality of holes formed thereon to provide a uniform plasma to the substrate. There is no need to have a head. In particular, as the number of magnet units 181 and 182 disposed up and down increases due to the shape of the magnetic field, the magnetic field formed by the magnet units 181 and 182 is uniformly formed in the entire plasma space PGS. . That is, as the number of magnet units 181 and 182 installed in the vertical direction increases, the uniformity of the magnetic field increases, the collision of electrons and the intensity of the electromagnetic field increase, and the uniformity of the plasma formed in the lead 140 is improved. Accordingly, the plasma etching apparatus 101 may improve the etching uniformity and the etching speed of the substrate.

In addition, as the area of the first and second electrode portions 161 and 161 covering the outer surface of the lid 140 and the volume of the first and second magnet units 181 and 182 increase, the plasma of the lid 140 is increased. The uniformity and density of the plasma formed in the space PGS increases. Therefore, the plasma etching apparatus 101 may adjust the uniformity and density of the plasma by optimizing the area of the first and second electrode units 161 and 162 and the volume of the first and second magnet units 181 and 182. .

3 to 5, the first magnet unit 181 is composed of a plurality of first magnets 181a. The plurality of first magnets 181a are continuously disposed along the circumference of the first electrode unit 161 and are connected to each other in parallel with each other. Each first magnet 181a has a rod shape extending in the width direction of the first electrode portion 161 and is a permanent magnet. The first magnet 181a includes an N pole 81 and an S pole 82, and the N pole 81 and the S pole 82 of the first magnet 181a have a width of the first electrode portion 161. Arranged side by side in the direction. In this embodiment, the N pole 81 of the first magnet 181a is positioned above the S pole 82 of the first magnet 181a.

The second magnet unit 182 is composed of a plurality of second magnets 182a. In this embodiment, the arrangement relationship of the plurality of second magnets 182a and the configuration of each of the second magnets 182a correspond to the arrangement relationship of the plurality of first magnets 181a and the configuration of each of the first magnets 181a. Since each is the same, a detailed description thereof will be omitted.

In this embodiment, the first and second magnet units 181 and 182 are each made of a plurality of permanent magnets 181a and 182a, but may be made of an electromagnet formed of a coil to receive a power to form a magnetic field.

Referring back to FIG. 1, the plasma etching apparatus 101 may further include a second RF generator 191 that provides RF power to the chuck 120. The RF power output from the second RF generator 191 is provided to the support plate 121 by adjusting its intensity through the matching box 192. When RF power is applied to the support plate 121, the flow rate of the ions formed inside the lead 140, that is, the ion energy increases, so that the plasma etching apparatus 101 may improve the etching speed of the substrate.

Hereinafter, a process of etching the substrate by the plasma etching apparatus 101 using plasma will be described in detail with reference to the accompanying drawings.

FIG. 6 is a diagram illustrating a process of etching a substrate in the plasma etching apparatus of FIG. 1.

Referring to FIG. 6, first, the substrate 10 is seated on an upper surface of the support plate 121 of the chuck 120.

Subsequently, process gas is introduced into the plasma space PGS of the lead 140 through the gas injection hole 141a of the lead 140.

In the plasma generation space PGS, an electromagnetic field is formed by the first and second electrode portions 161 and 162 of the plasma source portion and the grounded chuck 120, and the process gas is in a plasma state by the electromagnetic field. In this case, a magnetic field is formed in the plasma generation space PGS by the first and second magnet members 181 and 182, and the magnetic force lines LI of the magnetic field are the first magnet member 181 and the second magnet member. It is formed in the shape of a curve connecting the 182.

The collision of electrons is increased by the magnetic fields formed by the first and second magnet members 181 and 182 so that the plasma is uniformly formed and a high density plasma is formed. Accordingly, since the plasma etching apparatus 101 can uniformly provide high-density plasma to the entire upper surface of the substrate 10, the plasma etching apparatus 101 does not have a separate shower head for providing a uniform plasma. The uniformity may be efficiently improved, and the etching uniformity of the substrate 10 may be adjusted.

In addition, during the etching process of the substrate 10 using the plasma, the second RF generator 191 may provide RF power to the support plate 121. In this case, since high ion energy may be obtained by adjusting RF power output from the second RF generator 191, the plasma etching apparatus 101 may improve the etching speed of the substrate 10.

7 is a diagram illustrating a plasma etching apparatus according to another embodiment of the present invention.

Referring to FIG. 7, the plasma etching apparatus 102 has the same configuration as the plasma etching apparatus 101 illustrated in FIG. 1 except that the plasma etching apparatus 102 does not include the second RF generator 191. Therefore, in the following description of the configuration of the plasma etching apparatus 102, the same reference numerals are given to the same components as those of the plasma etching apparatus 101 shown in FIG. 1, and detailed description thereof will be omitted.

The plasma etching apparatus 102 does not include the second RF generator 191 of the plasma etching apparatus 101 shown in FIG. 1, but has a variable capacitor in the matching box 192 to obtain ion energy for etching. Can be. The variable capacitor is a capacitor that stores electric charge, and is a capacitor capable of changing capacitance, and is installed in the matching box 192. The variable capacitor adjusts the correction capacitance to match the resonance frequency between the first electrode portion 161 and the support plate 121, thereby increasing the ion energy. Thus, the plasma etching apparatus 102 may improve the etching speed of the substrate 10. In addition, since the plasma etching apparatus 102 may obtain high ion energy without providing a separate RF generator for providing RF power to the chuck 120, the plasma etching apparatus 102 may reduce costs.

8 is a view showing a plasma etching apparatus according to another embodiment of the present invention.

Referring to FIG. 8, the plasma etching apparatus 103 has the same configuration as the plasma etching apparatus 101 illustrated in FIG. 1 except that the second electrode portion 162 illustrated in FIG. 1 is not provided. Therefore, the same reference numerals are given to the same components as those of the plasma etching apparatus 101 shown in FIG. 1 among the components of the plasma etching apparatus 103. In addition, since the description of the components of the plasma etching apparatus 103 has been made in the configuration description of the plasma etching apparatus 101 shown in FIG. 1, detailed description thereof will be omitted. As shown in FIG. 8, the plasma etching apparatus 103 may not include the second electrode unit 162 shown in FIG. 1 according to process efficiency and process conditions, thereby reducing manufacturing costs. have.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

101, 102, 103: plasma etching apparatus 110: chamber
120: Chuck 140: Lead
161 and 162: electrode unit 170: first RF generator
181, 182: magnet unit 191: second RF generator
192: Matching Box 193: Variable Condenser

Claims (24)

delete delete delete delete A housing providing an etching space in which an etching process of the substrate is performed, having a at least one gas inlet through which a process gas is introduced, and a plasma space in which a plasma for etching the substrate is formed;
A substrate support member installed inside the housing and on which the substrate is mounted and grounded; And
A first electrode unit installed on an outer wall of the housing to receive RF power from the outside, and at least one magnet unit installed on one side of the first electrode unit to form a magnetic field in the housing, and using the process gas To include the plasma source portion for generating the plasma;
The housing includes:
A chamber which provides a process space in which a process of the substrate is made and which is open at the top; And
A lid provided on the chamber and coupled to the chamber and providing the plasma space,
The lead is an upper surface on which the gas inlet is formed, extends perpendicularly to the upper surface to form the plasma space, a sidewall on which the first electrode portion and the magnet unit are installed, and a curved portion connecting the sidewall and the upper surface. It is provided with the connection part which consists of,
The plasma source unit may further include a second electrode unit disposed in the connection unit, spaced apart from the first electrode unit, and having a curved shape corresponding to the connection unit. The method of claim 5,
The lead is formed in a dome shape, the gas inlet is plasma etching apparatus, characterized in that formed in the center of the lead. The method according to claim 6,
The first electrode portion is provided on the outer wall of the lead, the magnet unit is plasma etching apparatus, characterized in that provided on the outer surface of the first electrode portion. The method of claim 5, wherein the plasma source unit,
Plasma power is connected to the first electrode portion has the same potential as a whole, and the ground or bias power is connected to the substrate support member, the plasma etching apparatus, characterized in that the plasma source portion of the capacitively coupled plasma type. The method of claim 5,
And the first electrode unit and the magnet unit each have a ring shape to surround sidewalls of the housing. 10. The method according to any one of claims 5 to 9,
The magnet unit is provided with a plurality,
The plurality of magnet units are spaced apart from each other in the width direction of the first electrode portion, each plasma etching apparatus, characterized in that surrounding the first electrode portion. The method of claim 10, wherein each of the plurality of magnet units,
Plasma etching apparatus comprising a plurality of magnets continuously arranged along the circumference of the first electrode portion parallel to each other. 12. The plasma etching apparatus of claim 11, wherein the plurality of magnets are disposed in contact with each other. The method of claim 11,
Each of the plurality of magnets includes two different poles arranged side by side in the width direction of the first electrode part,
Two magnet units adjacent to each other are plasma etching apparatus, characterized in that different poles are arranged adjacent to each other. The method of claim 11,
Wherein each of the magnets is a permanent magnet. The method of claim 10,
The magnet unit is a plasma etching apparatus, characterized in that made of electromagnets. The method of claim 5, wherein the plasma source unit,
And a first RF generator configured to apply the RF power to the first electrode part. 17. The method of claim 16,
And a second RF generator for providing RF power to the substrate support member. 17. The method of claim 16,
And a variable capacitor connected to the substrate support member and adjusting a resonance frequency between the substrate support member and the first electrode portion.


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