KR20100006708A - Plasma treatment equipment - Google Patents

Abstract

PURPOSE: A plasma process device is provided to compensate for the lowering of the plasma density in the center of a process chamber by installing at least one antenna in an upper side and a lateral side of the process chamber. CONSTITUTION: A plasma process device includes a reactive chamber(100) and an antenna(110) installed in an upper side and a lateral side of a reactive chamber. The plasma process device includes a shower head(130) and a bottom electrode(150) to face each other in the reactive chamber. The reactive chamber maintains the substrate processing area airtightly and includes a reactive unit(100a) and a cover(100b). The antenna includes first to third antennas(110a,110b,110c) with different diameters. The first and second antennas are installed in the upper side of the reactive chamber. The third antenna surrounds the reactive chamber.

Description

Plasma treatment equipment

The present invention relates to a plasma processing apparatus, and more particularly, to a plasma processing apparatus capable of improving plasma density and uniformity.

With the development of next-generation semiconductors, micro electro mechanical systems (MEMS) and nanodevice technologies, the formation of ultra-fine patterns, precise process control, and processing of large-diameter wafers have become important challenges. Accordingly, the specific gravity of the plasma process is increasing, and a large area of high density plasma formation and control technology is essential.

The plasma processing apparatus is classified into a capacitively coupled plasma (CCP) and an inductively coupled plasma (ICP) method according to the electrode type. In general, the CCP method generates a plasma by an electric field formed in a space between electrodes by applying a high frequency to a parallel plate electrode, and a high power power source is required to generate a high density plasma. In contrast, the ICP method generally generates a plasma by applying a high frequency to a spiral antenna and accelerating electrons in the chamber with an electric field induced by a change in a magnetic field caused by a high frequency current flowing into the antenna. The ICP method has a simple structure and can generate high density and large area plasma at low pressure.

In the ICP-type plasma processing apparatus, a spiral antenna is installed on the upper side or the side of the process chamber. When the spiral antenna is installed in the upper part of the chamber, the plasma density increases in the middle part of the antenna because the strength of the magnetic field is increased compared to other parts. Therefore, the etching speed of the middle portion of the wafer is faster than the other portions, thereby reducing the etching uniformity. In order to prevent this, the thickness of the outer wall of the chamber in the middle portion of the antenna is increased to lower the plasma density of the middle portion of the antenna. However, the fabrication of the chamber is complicated because the thickness of the chamber outer wall must be made different. In addition, when the antenna is provided on the side of the chamber, the intensity of the magnetic field around the antenna is strong, so that the plasma density of the central portion of the chamber away from the antenna is reduced. Therefore, the etching speed of the center portion of the wafer is lower than that of other portions.

The present invention provides a plasma processing apparatus that can improve the density and uniformity of plasma.

The present invention provides a plasma processing apparatus that installs antennas on the top and sides of a process chamber, and connects them in parallel to apply the same high frequency power.

The present invention provides a plasma processing apparatus that can install a plurality of antennas in the upper part of the process chamber and connect a variable capacitor to the upper antenna to adjust the difference in inflow current.

Plasma processing apparatus according to an aspect of the present invention includes a reaction chamber for forming a space therein; And at least one antenna installed at each of the upper and side portions of the reaction chamber, and the antennas are connected in parallel.

At least two antennas are installed on an upper portion of the reaction chamber, and at least one antenna is installed on the side of the reaction chamber.

The antenna installed in the upper portion of the reaction chamber includes a circular first antenna installed in a central region of the reaction chamber and a circular second antenna formed spaced apart from the circular first antenna.

At least two antennas installed in the upper portion of the reaction chamber are each connected to a capacitor in series.

It further comprises at least one frequency variable antenna installed on the side of the reaction chamber.

In the plasma processing apparatus of the present invention, at least one antenna is provided at each of the upper side and the side side of the process chamber. For example, the antenna on the top of the process chamber is installed in duplicate, and the antenna on the side of the process chamber is installed in a single. In addition, a variable capacitor is connected to the dual antenna above the process chamber, and the dual antenna above the process chamber and a single antenna on the side of the process chamber are connected in parallel with the power supply.

Therefore, the phenomenon that the plasma density decreases at the center of the process chamber by the antenna at the side of the process chamber can be efficiently compensated by the dual antenna at the top of the process chamber. Therefore, the overall plasma density and uniformity can be improved. In addition, by adjusting the capacity of the variable capacitor connected to the antenna on the upper part of the process chamber, the uniformity of the plasma may be further improved, and the yield of the process may be improved by adjusting the plasma density of the necessary part inside the process chamber.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention and to those skilled in the art. It is provided for complete information.

1 is a schematic cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of an antenna according to an embodiment of the present invention, and FIG. 3 is a circuit diagram of the antenna.

Referring to FIG. 1, a plasma processing apparatus according to an exemplary embodiment of the present invention includes a reaction chamber 100 and antennas 110a, 110b, and 110c installed at upper and side portions of the reaction chamber 100. In addition, the reaction chamber 100 includes a shower head 130 and the lower electrode portion 150 that are located opposite each other.

The reaction chamber 100 keeps the substrate processing area airtight and at the same time secure grounded. The reaction chamber 100 is located on the reaction part 100a having a predetermined space with a reaction part 100a having a predetermined space, including a substantially circular planar part and a sidewall part extending upwardly from the planar part. It includes a cover (100b) to keep the airtight. In addition, the reaction part 100a and the cover 110b may include an insulating material so that the magnetic field may be effectively transferred into the reaction chamber 100, and may be made of, for example, a ceramic material. Of course, the reaction part 100a and the cover 100b may be manufactured in various shapes in addition to the circular shape, for example, may be manufactured in a shape corresponding to the shape of the substrate.

The antenna 110 has different diameters as shown in FIG. 2 and includes circular first, second and third antennas 110a, 110b and 110c. That is, the diameter of the second antenna 110b is larger than that of the first antenna 110a, and the diameter of the third antenna 110c is larger than the second antenna 110b. Here, the first and second antennas (110a and 110b) is installed on the upper portion of the reaction chamber 100, the third antenna (110c) is installed to surround the side of the reaction chamber (100). That is, the first antenna 110a is installed at, for example, an upper center region of the reaction chamber 100, and the second antenna 110b is spaced apart from the first antenna 110a and is an upper edge region of the reaction chamber 100. Is installed on. In addition, the first, second and third antennas 110a, 110b and 110c are connected in parallel with the first high frequency power source 122. That is, one terminal is connected to the first high frequency power supply 122 and the other terminal is grounded in the first, second and third antennas 110a, 110b, and 110c. Also, the first and second variable capacitors C1 and C2 are connected to the first and second antennas 110a and 110b with the first matcher 121.

One side of the antenna 100 is connected to the first high frequency power source 122 through the first matcher 121. A high frequency of 13.56 MHz is output from the first high frequency power source 122, and the high frequency magnetic field generated from the antenna 110 is applied to the plasma region in the reaction chamber 100. The first matcher 121 detects the impedance of the reaction chamber 100 and generates an impedance imaginary component of a phase opposite to the imaginary component of the impedance so that the maximum power in the reaction chamber 100 is equal to the pure resistance of the real component. And to generate an optimal plasma accordingly.

The showerhead 130 is located at the top in the reaction chamber 100. The shower head 130 includes an upper electrode plate 131 having a plurality of discharge holes 132 formed therein, and an electrode support 133 that supports the upper electrode plate 131 and is made of a conductive material. The electrode support 133 and the upper electrode plate 131 of the shower head 130 are installed in the reaction chamber 100, but the electrode support 133 may be installed outside the reaction chamber 100. That is, at least a part of the lid 100b of the reaction chamber 100 may be configured by the upper electrode plate 131, and the electrode support 133 may be provided on the upper portion thereof.

The gas inlet 140 is installed at the upper center of the electrode support 133, and the gas inlet 140 is branched into a plurality of lines to connect the gas supply source 141. Each line is equipped with a valve 142 and a mass flow controller 143, which are connected to a gas source 141. Therefore, the reactive gas for plasma treatment is supplied from the gas supply source 141 to the shower head 130. As the reaction gas, a gas containing a halogen element such as a fluorocarbon gas or a hydrofluorocarbon gas may be appropriately used. Ar, He, C ₄ F ₈ , N ₂ gas may also be provided.

The lower electrode unit 150 is installed at a lower portion of the reaction chamber 100 to face the shower head 130. The lower electrode unit 150 is configured to electrostatically adsorb the substrate lifter 151 positioned on the bottom of the reaction chamber 100, the lower electrode 152 positioned above the substrate lifter 151, and the substrate 10. An electrostatic chuck 153. When the substrate 10 to be processed is seated on the lower electrode unit 150, the substrate lifter 151 moves the lower electrode unit 150 to approach the shower head 130. In addition, the chiller 154 is connected to the lower electrode 152, and the refrigerant circulation unit 155 is connected between the lower electrode 152 and the chiller 154. By introducing and circulating the refrigerant from the chiller 154 into the refrigerant circulation unit 155, the cooling heat is transferred to the substrate 10 through the lower electrode 152. That is, the temperature of the process surface of the board | substrate 10 can be controlled to desired temperature.

In addition, the second matching unit 161 and the second high frequency power source 162 are connected to the lower electrode 152, which serves to supply power into the reaction chamber 100.

An electrostatic chuck 153 having substantially the same shape as the substrate 10 is provided on the lower electrode 152. The electrostatic chuck 153 has a lower electrode plate (not shown) provided between the insulating materials, and DC power is applied from the high voltage DC power supply 163 connected to the lower electrode plate. Thus, the substrate 10 is held by the electrostatic chuck 153 by the electrostatic force. In this case, the substrate 10 may be held by a mechanical force in addition to the electrostatic force.

An annular focus ring 164 is provided to surround the outer circumferential surfaces of the lower electrode 152 and the electrostatic chuck 153. The focus ring 164 is made of an insulating material, and serves to direct the plasma to the substrate 10.

In addition, an exhaust pipe 171 is connected to the lower side of the reaction chamber 100, and an exhaust device 172 is connected to the exhaust pipe 171. In this case, a vacuum pump such as a turbo molecular pump may be used as the exhaust device 171, so that the inside of the reaction chamber 100 may be vacuum sucked up to a predetermined pressure, for example, to a predetermined pressure of 0.1 mTorr or less. It is composed. The exhaust pipe 171 may be installed at the lower side of the reaction chamber 100 as well as the side surface. In addition, a plurality of exhaust pipes 171 and a vacuum pump 172 may be further installed to reduce the time for evacuation. Moreover, the gate valve 173 is provided in the reaction chamber 100 side wall, and the board | substrate 10 is conveyed with the adjacent load lock chamber (not shown) in the state which opened this gate valve 173. FIG. The gate valve 173 is installed on one side of the reaction chamber 100, but may be further formed on the other side facing the one side. This may carry out the substrate 10 introduced through one side through the other side.

Referring to the plasma processing method using a plasma processing apparatus according to an embodiment of the present invention configured as described above are as follows.

First, the substrate 10 having completed the preceding process is brought into the reaction chamber 100 after the gate valve 173 is opened. The loaded substrate 10 is seated on an upper surface of the electrostatic chuck 153, and a high voltage direct current power source 163 is applied to the electrostatic chuck 153 so that the substrate 10 is held by the electrostatic chuck by the electrostatic chuck 153. do.

Thereafter, the inside of the reaction chamber 100 is maintained in a vacuum state by the vacuum pump 172, the valve 142 connected to the gas source 141 is opened to control the flow rate by the mass flow controller 143 The reaction gas is supplied from the gas supply source 141. In this case, one or more reactant gases may be introduced as necessary. The reaction gas is provided to the shower head 130 through the gas line and the gas introduction pipe 140, and is uniformly injected into the reaction chamber 100 through the discharge hole 132 of the upper electrode plate 131. At this time, the reaction chamber 100 is maintained at a predetermined pressure while the reaction gas is supplied.

The high frequency power for plasma generation is applied from the first high frequency power supply 122 to the first, second and third antennas 110a, 110b and 110c, and the high frequency power is supplied from the second high frequency power source 162 to the lower electrode portion. Is applied to 150. At this time, the high frequency current is applied to the antenna 110 to generate an electric field induced by the high frequency around the reaction chamber 100, and accelerate the electrons in the reaction chamber 100 by the electric field to generate the plasma. In this case, the first and second antennas 110a and 110b compensate for the decrease in the plasma density of the central portion of the reaction chamber 100 by the third antenna 110c, thereby improving the density and uniformity of the plasma.

Therefore, the reaction gas jetted from the shower head 130 is converted into plasma, and the substrate 10 is processed by this plasma.

Subsequently, when the processing of the substrate 10 by the plasma is completed, power supply is stopped from the high voltage direct current power source 132, the first high frequency power source 122, and the second high frequency power source 162, and the substrate 10 is connected to the gate valve 173. It is carried out to the outside of the reaction chamber 100 through) to complete the process.

As described above, in the plasma processing apparatus of the present invention, the first and second antennas 110a and 110b are installed on the reaction chamber 100, and the third antenna 110c is provided on the side of the reaction chamber 100. By installing them in parallel, high frequency power is applied from the first high frequency power source 122. Accordingly, the first and second antennas 110a and 110b compensate for the decrease in the plasma density of the center portion of the reaction chamber 100 by the third antenna 110c, thereby improving the density and uniformity of the plasma. However, since the characteristics of the lengths and materials of the first and second antennas 110a and 110b and the third antenna 110c connected in parallel are different, a difference in applied current is generated, and accordingly, the inside of the reaction chamber 100 Changes in plasma density may occur locally. Accordingly, the variable capacitors C1 and C2 are connected to the first and second antennas 110a and 110b, respectively, in order to generate a high-density uniform plasma in the reaction chamber 100, and the variable capacitors C1 and C2, respectively. By adjusting the capacitance of the first and second antennas 110a and 110b and the third antenna 110c connected in accordance with the characteristics such as the length or material of the difference in the generated current can be adjusted. That is, as shown in the circuit diagram of FIG. 3, the currents flowing into the first and second antennas 110a and 110b are referred to as I1 and I2, respectively, and the current flowing into the third antenna 110c is referred to as I3.

Current is I = I1 + I2 + I3 The current flowing into each antenna may be represented by [Equation 1], [Equation 2] and [Equation 3].

In the above equations, L1, L2, and L3 values are determined according to the characteristics of the first, second, and third antennas 110a, 110b, and 110c. Thus, the first and second values may be adjusted by adjusting the capacitance of the variable capacitor. I1 and I2 current values flowing into the second antennas 110a and 110b may be adjusted.

In addition, a frequency-variable magnetic field antenna may be further installed below the third antenna 110c to increase the plasma density. Increasing the frequency applied to the frequency-variable magnetic antenna increases the mobility of charged particles in the plasma, increases the number of collisions, and consequently increases the density of the plasma. In addition, the position of the magnetic field antenna can be installed to be moved up and down to enable the position change according to the characteristics of the reaction chamber.

Although the technical spirit of the present invention has been described in detail according to the above embodiment, it should be noted that the above embodiment is for the purpose of description and not for the purpose of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention. For example, more than two antennas installed on the upper portion of the reaction chamber 100 may be installed. In addition, two or more antennas installed on the side of the reaction chamber 100 may be installed, and a plurality of variable magnetic antennas may also be installed.

1 is a schematic cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention.

2 is a block diagram of an antenna according to an embodiment of the present invention.

3 is a circuit diagram of an antenna according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: reaction chamber 110: antenna

110a: first antenna 110b: second antenna

110c: third antenna 130: showerhead

150: lower electrode portion

Claims (5)

A reaction chamber defining a space therein; And At least one antenna installed on each of the upper and side portions of the reaction chamber, The antenna is a plasma processing apparatus connected in parallel. The plasma processing apparatus of claim 1, wherein at least two antennas are installed at an upper portion of the reaction chamber, and at least one antenna is installed at a side of the reaction chamber. 3. The plasma of claim 2, wherein the antenna installed on the reaction chamber comprises a circular first antenna disposed in a center region of the reaction chamber and a circular second antenna spaced apart from the circular first antenna. Processing unit. The plasma processing apparatus of claim 2, wherein at least two antennas installed on the reaction chamber are connected in series with a capacitor. The plasma processing apparatus of claim 1, further comprising at least one frequency-variable antenna installed at a side of the reaction chamber.

Images