Patent Application
20230082246
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-151496, filed on Sep. 16, 2021; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a substrate processing apparatus, and a method for manufacturing a semiconductor device.
In a process for manufacturing a semiconductor device, in a substrate processing apparatus, a predetermined process may be performed on a substrate placed in a processing chamber. In order to improve throughput for manufacturing the semiconductor device, it is desired that the substrate is efficiently processed in the substrate processing apparatus.
In general, according to one embodiment, there is provided a substrate processing apparatus including a first electrode, a second electrode, a third electrode, a first power supply circuit, a second power supply circuit and a control line. The first electrode is arranged in a processing chamber, and on which a substrate can be placed. The second electrode faces the first electrode. The third electrode is arranged along a side wall in the processing chamber and facing the first electrode. The first power supply circuit is connected to the first electrode. The second power supply circuit is connected to the third electrode. The control line is connected to the first power supply circuit and the second power supply circuit.
Exemplary embodiments of a substrate processing apparatus will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments.
The substrate processing apparatus according to the embodiment includes both an etching electrode and a film forming electrode. The etching includes dry etching such as reactive ion etching (RIE). The film formation includes physical film formation such as sputtering. For example, in the substrate processing apparatus, efficient processing of a substrate is achieved by devising how to drive the etching electrode and the film forming electrode.
Specifically, a substrate processing apparatus 1 includes, as illustrated in
The controller 2 integrally controls each component of the substrate processing apparatus 1. The controller 2 stores recipe information including processing procedures for a plurality of process parameters, and can control each component according to the recipe information. The plurality of process parameters include process parameters related to anisotropic etching conditions. The controller 2 may be arranged in the main body of the substrate processing apparatus 1, or may be provided outside the main body of the substrate processing apparatus 1 and communicably connected to each component of the substrate processing apparatus 1 via a wireless communication line or a wired communication line.
The lower electrode 10 is arranged in a processing chamber CH. The lower electrode 10 may have a substantially disk shape extending in the XY direction with the Z direction as the axis. A substrate SB to be treated can be placed on the surface (a surface on +Z-side) 10a of the lower electrode 10. The lower electrode 10 may be formed of a conductive material such as metal. The lower electrode 10 is used as both an etching electrode and a film forming electrode.
The processing chamber CH is a space formed by being surrounded by a vacuum vessel 2. The vacuum vessel 2 has a side wall 2b extending in a tube shape (for example, a cylindrical tube shape); a +Z-side end of the side wall 2b is closed by an upper wall 2a, and a −Z-side end of the side wall 2b is closed by a bottom wall 2c. The upper wall 2a may be formed of, for example, a dielectric.
The gas supply system 70 is configured to be able to supply a processing gas into the processing chamber CH. The gas supply system 70 includes a gas panel 71, a flow regulator 72, and a supply pipe 73. The supply pipe 73 communicates with the processing chamber CH through an opening provided in the upper wall 2a. The gas supply system 70 supplies, under the control of the controller 2, the processing gas stored in the gas panel 71 into the processing chamber CH through the supply pipe 73 while adjusting the flow rate of the processing gas by the flow regulator 72.
The exhaust system 80 is configured to be able to exhaust the processed processing gas from the processing chamber CH. The exhaust system 80 includes an exhaust device 81, a gate valve 82, and an exhaust pipe 83. The exhaust pipe 83 communicates with the processing chamber CH through an opening provided in the bottom wall 2c. The exhaust system 80 opens, under the control of the controller 2, the gate valve 82 so that the processed processing gas is exhausted from the processing chamber CH to the exhaust device 81.
The upper electrode 20 is arranged outside the processing chamber CH, on the +Z-side of the processing chamber CH. The upper electrode 20 may have a substantially disk shape extending in the XY direction with the Z direction as the axis. The upper electrode 20 is arranged on the +Z-side of the lower electrode 10 and faces the lower electrode 10 in the Z direction with the upper wall 2a interposed therebetween. The upper electrode 20 includes an antenna coil 21. The antenna coil 21 is formed by a conductive wire wound along a substantially disk shape extending in the XY direction with the Z direction as the axis. The antenna coil 21 is not illustrated in
The middle electrode 30 is disposed in the processing chamber CH. The middle electrode 30 is arranged along the side wall 2b in the processing chamber CH. The middle electrode 30 may have a substantially cylindrical shape extending in the Z direction with the Z direction as the axis. The middle electrode 30 is disposed on the +Z-side of the lower electrode 10 and faces the lower electrode 10 in a direction inclined from the Z direction. The position of the middle electrode 30 in the Z direction may be between the position of the upper electrode 20 in the Z direction and the position of the lower electrode 10 in the Z direction.
As illustrated in
The power supply circuit 50 illustrated in
The power supply circuit 50 includes a source power supply 51 and a matching circuit 52. The source power supply 51 generates radio frequency power having a frequency FR1 and supplies the radio frequency power to the antenna coil 21. The frequency FR1 is a frequency suitable for plasma generation, and is, for example, 13.56 MHz. The matching circuit 52 performs impedance matching so that the impedance on the source power supply 51 side with respect to the matching circuit 52 and the impedance on the antenna coil 21 side with respect to the matching circuit 52 are equal. The antenna coil 21 uses the radio frequency power supplied in a state where the impedance matching is performed to generate an electromagnetic wave (radio frequency magnetic field). The electromagnetic wave generated by the antenna coil 21 passes through the upper wall 2a (dielectric wall) so as to be introduced into the space of the processing chamber CH. In the space of the processing chamber CH, the processing gas is discharged to generate plasma PL, and ions (for example, F+, CF3+, and/or the like) are generated from the processing gas together with radicals (F radical, CF radical, and/or the like).
The power supply circuit 40 is connected to the lower electrode 10. The power supply circuit 50 can generate, under the control of the controller 2, radio frequency power and supply the radio frequency power to the lower electrode 10.
The power supply circuit 40 includes a bias power supply 41, a source power supply 42, and a matching circuit 43. The bias power supply 41 generates radio frequency power having a frequency FR2 (relatively low frequency) and supplies the radio frequency power to the lower electrode 10. The frequency FR2 is lower than the frequency FR1. The frequency FR2 is a frequency suitable for ion acceleration, and is, for example, 2.0 MHz. The source power supply 42 can generate radio frequency power having the frequency FR1; however, the source power supply 42 is not used in the present embodiment. The matching circuit 43 performs impedance matching so that the impedance on the bias power supply 41 side with respect to the matching circuit 43 and the impedance on the lower electrode 10 side with respect to the matching circuit 43 are equal. The lower electrode 10 uses the radio frequency power having the frequency FR2 supplied in a state where the impedance matching is performed to accelerate the ions toward the lower electrode 10.
Thus, the substrate processing apparatus 1 can etch the substrate SB to be processed. At this time, a by-product can adhere to the middle electrode 30. The by-product may be a carbon component.
Here, the middle electrode 30 has, as illustrated in
The power supply circuit 60 illustrated in
The power supply circuit 60 includes a sputtering power supply 61 and a matching circuit 62. The sputtering power supply 61 generates radio frequency power having a frequency FR3 and supplies the radio frequency power to the middle electrode 30. The frequency FR3 is lower than the frequency FR1 and lower than the frequency FR2. The frequency FR3 is a frequency suitable for sputtering, and is, for example, 100 kHz. The matching circuit 62 performs impedance matching so that the impedance on the sputtering power supply 61 side with respect to the matching circuit 62 and the impedance on the middle electrode 30 side with respect to the matching circuit 62 are equal. The middle electrode 30 uses the radio frequency power having the frequency FR3 supplied in a state where the impedance matching is performed to strike the ions on the middle electrode 30. Thus, the by-product adhered to the middle electrode 30 is sputtered toward the lower electrode 10.
The control line 90 illustrated in
Specifically, the power supply circuit 40 and the power supply circuit 60 transmit and receive, via the control line 90, a synchronization signal related to at least one of the power supply by the power supply circuit 40 and the power supply by the second power supply circuit. The synchronization signal may be a pulse signal having a predetermined pulse width. The predetermined pulse width may be a pulse width with which the reception destination can identify the start of power supply and/or the stop of power supply.
For example, the matching circuit 43 may transmit, in response to the stop of power supply, a synchronization signal to the matching circuit 62 via the control line 90. According to the synchronization signal, the matching circuit 62 can grasp the timing at which the power supply circuit 40 stops power supply to the lower electrode 10, and can start impedance matching operation.
The matching circuit 62 may transmit, in response to the stop of power supply, a synchronization signal to the matching circuit 43 via the control line 90. According to the synchronization signal, the matching circuit 43 can grasp the timing at which the power supply circuit 60 stops power supply to the middle electrode 30, and can start impedance matching operation.
The operation of the substrate processing apparatus 1 will be described below with reference to
Before timing t1, a substrate W is placed on the lower electrode 10, and the exhaust system 80 exhausts the processing chamber CH so that the processing chamber CH is in a depressurized state.
At timing t1, the power supply circuit 50 performs impedance matching, and starts supplying radio frequency power having the frequency FR1 from the source power supply 51 to the upper electrode 20. At the same time, the gas supply system 70 starts to supply the processing gas into the processing chamber CH. Consequently, plasma is generated in the processing chamber CH.
After timing t1, a state in which the radio frequency power is supplied from the power supply circuit 50 to the upper electrode 20 is maintained, and a state in which the processing gas having a substantially constant gas flow rate F1 is supplied into the processing chamber CH is maintained. Consequently, a state in which plasma is generated in the processing chamber CH is maintained.
At timing t2, the power supply circuit 40 performs impedance matching, and starts supplying radio frequency power having the frequency FR2 from the bias power supply 41 to the lower electrode 10. Consequently, the substrate W starts to be etched in the processing chamber CH.
During the period from timing t2 to timing t3, etching processing of the substrate W as illustrated in
When etching processing is performed under the condition of anisotropic etching using the resist pattern RP as a mask, immediately after the start of etching, a top portion 101a between the hole patterns HP in the semiconductor oxide film 101 is temporarily covered with a by-product film corresponding to the processing gas; however, when the semiconductor film 104 is exposed at the bottom portion of the hole patterns HP, the by-product film is etched and disappears. At this time, the by-product may adhere to the surface 30a of the middle electrode 30. The by-product contains, for example, a carbon component.
Thus, as illustrated in
At timing t3 illustrated in
The power supply circuit 40 transmits, in response to the stop of power supply, a synchronization signal to the power supply circuit 60 via the control line 90. The power supply circuit 60 receives the synchronization signal via the control line 90. According to the received synchronization signal, the power supply circuit 60 can recognize that the power supply circuit 40 has stopped supplying power to the lower electrode 10.
At timing t4 when a predetermined time has elapsed since the synchronization signal was received, the power supply circuit 60 performs impedance matching, and starts supplying the radio frequency power having the frequency FR3 from the sputtering power supply 61 to the middle electrode 30.
Thus, in the period from timing t4 to timing t5, the by-product is deposited (sputtered) from the middle electrode 30 to the lower electrode 10, and a by-product film (for example, a film containing a carbon component) 110 is formed on the substrate W, as illustrated in
At timing t5, the power supply circuit 60 stops supplying the radio frequency power to the middle electrode 30. Consequently, the sputtering of the substrate W in the processing chamber CH is stopped.
The power supply circuit 60 transmits, in response to the stop of power supply, a synchronization signal to the power supply circuit 40 via the control line 90. The power supply circuit 40 receives the synchronization signal via the control line 90. According to the received synchronization signal, the power supply circuit 40 can recognize that the power supply circuit 60 has stopped supplying power to the middle electrode 30.
At timing t6 when a predetermined time has elapsed since the synchronization signal was received, the power supply circuit 40 performs impedance matching, and starts supplying radio frequency power of the frequency FR2 from the bias power supply 41 to the lower electrode 10. Consequently, the substrate W starts to be etched in the processing chamber CH.
During the period from timing t6 to timing t7, etching processing of the substrate W as illustrated in
At timing t7 illustrated in
The power supply circuit 40 transmits, in response to the stop of power supply, a synchronization signal to the power supply circuit 60 via the control line 90. The power supply circuit 60 receives the synchronization signal via the control line 90. According to the received synchronization signal, the power supply circuit 60 can recognize that the power supply circuit 40 has stopped supplying power to the lower electrode 10.
At timing t8 when a predetermined time has elapsed since the synchronization signal was received, the power supply circuit 60 performs impedance matching, and starts supplying the radio frequency power having the frequency FR3 from the sputtering power supply 61 to the middle electrode 30.
Thus, in the period from timing t8 to timing t9, the by-product is deposited (sputtered) from the middle electrode 30 to the lower electrode 10, and the by-product film 110 is formed on the substrate W, as illustrated in
After timing t10, operations similar to those at timing t6 to timing t10 are repeated.
A period ET1 from timing t2 to timing t3, a period ET2 from timing t6 to timing t7, and a period ET3 from timing t10 to timing t11 illustrated in
A period ST1 from the timing t4 to the timing t5 and a period ST2 from the timing t8 to the timing t9 are sputtering periods in which sputtering is performed. A period TP11 from the timing t1 to the timing t4, a period TP12 from the timing t5 to the timing t8, and a period TP13 after the timing t9 are sputtering stop periods in which sputtering period is stopped.
The etching periods ET1, ET2, and ET3 are included in the sputtering stop periods TP11, TP12, and TP13, respectively. The sputtering periods ST1 and ST2 are included in the etching stop periods TP1 and TP2, respectively. In other words, the substrate processing apparatus 1 can perform etching and sputtering alternately and exclusively. For example, switching between etching and sputtering can be performed at high speed (for example, a speed comparable to a pulse frequency).
As described above, in the embodiment, in the substrate processing apparatus 1, the power supply circuit 40 and the power supply circuit 60 are connected via the control line 90. The power supply circuit 40 and the power supply circuit 60 transmit and receive, via the control line 90, a synchronization signal related to at least one of the power supply by the power supply circuit 40 and the power supply by the power supply circuit 60. In response to the synchronization signal, the power supply circuit 40 and the power supply circuit 60 synchronize the power supply by the power supply circuit 40 and the power supply by the power supply circuit 60. Thus, it is possible to alternately perform etching and film formation (for example, sputtering) while maintaining the supply of the same processing gas into the processing chamber CH, and therefore it is possible to efficiently perform etching processing for a plurality of closely arranged hole patterns that are difficult to mask with a resist pattern, for example. In other words, the substrate W can be efficiently processed.
For example, in a case where an etching protection film corresponding to the by-product film is deposited on the substrate W by In-situ atomic layer deposition (ALD), since a processing gas different from that used for etching is used, the processing is put on standby during an operation time when the gas supply system 70 switches the processing gas. Thus, throughput for processing the substrate W decreases, so that productivity in a method for manufacturing a semiconductor device including the processing of the substrate W may decrease.
In contrast, in the embodiment, it is possible to alternately perform etching and film formation (for example, sputtering) while maintaining the supply of the same processing gas into the processing chamber CH. Thus, when etching is performed substantially with no dry etching mask without being able to apply a resist or the like, productivity of the method for manufacturing the semiconductor device including the processing of the substrate W can be improved.
The lower electrode 10 may have another shape, instead of being limited to the substantially disk shape extending in the XY direction with the Z direction as the axis. The lower electrode 10 may have a substantially rectangular parallelepiped shape extending in the XY direction with the Z direction as the axis.
The upper electrode 20 may have another shape, instead of being limited to the substantially disk shape extending in the XY direction with the Z direction as the axis. The upper electrode 20 may have a substantially rectangular parallelepiped shape extending in the XY direction with the Z direction as the axis.
The middle electrode 30 may have another shape, instead of being limited to the substantially cylindrical shape extending in the Z direction with the Z direction as the axis. The middle electrode 30 may have a substantially rectangular tube shape extending in the Z direction with the Z direction as the axis. In this case, the middle electrode 30 extends in a rectangular annular shape when viewed from the XY plane.
The middle electrode 30 may be provided with a temperature control mechanism. With such a configuration, the adhesion amount of the by-product to the middle electrode 30 can be adjusted.
Alternatively, a middle electrode 30i of a substrate processing apparatus li may be divided into a plurality of sub-electrodes 31i to 34i as illustrated in
For example, the sub-electrodes 31i to 34i illustrated in
Alternatively, a middle electrode 30j of a substrate processing apparatus 1j may be configured such that a surface 30aj thereof is inclined in a direction facing the lower electrode 10 with respect to the side wall 2b, as illustrated in
The middle electrode 30j may have a substantially hollow truncated cone shape in which the width in the XY direction decreases toward the +Z direction with the Z direction as the axis. An inner surface of the substantially hollow truncated cone shape constitutes the surface 30aj of the middle electrode 30j. The surface 30aj is inclined in a direction toward the lower electrode 10. With such a configuration, in sputtering, when ions of the processing gas are struck against the surface 30aj of the middle electrode 30j, the by-product adhering to the surface 30aj of the middle electrode 30j is more likely to be sputtered to the substrate W on the lower electrode 10.
Alternatively, a middle electrode 30k of a substrate processing apparatus 1k may be divided into a plurality of sub-electrodes 31k to 34k as illustrated in
For example, the sub-electrodes 31k to 34k illustrated in
The above embodiment is described based on an example in which the substrate processing apparatus 1 configured by adding a film forming electrode and a power supply circuit to a configuration corresponding to an inductive coupling plasma (ICP) type RIE apparatus; however, the substrate processing apparatus 1 is not limited to this configuration. For example, the substrate processing apparatus 1 may be configured by adding a film forming electrode and a power supply circuit to a configuration corresponding to an electron cycrotron resonance (ECR) type RIE apparatus.
Alternatively, a substrate processing apparatus 201 may be configured by adding the middle electrode 30 and the power supply circuit 60 for film formation to a configuration corresponding to a two-frequency parallel plate type (capacitive coupling type) RIE apparatus, as illustrated in
The substrate processing apparatus 201 includes an upper electrode 220 instead of the upper electrode 20 (see
The upper electrode 220 is arranged in the processing chamber CH so as to face the lower electrode 10. The upper electrode 220 is arranged in the processing chamber CH, on the +Z-side of the lower electrode 10, and extends in the XY direction. The upper electrode 220 is provided with an opening penetrating in the Z direction. The supply pipe 73 of the gas supply system 70 communicates with the processing chamber CH via the opening provided in the upper wall 2a and the opening provided in the upper electrode 220.
The source power supply 42, instead of the source power supply 51 (see
For example, at timing t1 illustrated in
On the other hand, at timing t2, the power supply circuit 40 performs impedance matching, and starts supplying radio frequency power having the frequency FR2 from the bias power supply 41 to the lower electrode 10. In other words, the power supply from the bias power supply 41 to the lower electrode 10 is started. Consequently, the substrate W starts to be etched in the processing chamber CH.
At timing t3, the power supply circuit 40 stops supplying the radio frequency power having the frequency FR2 to the lower electrode 10. In other words, the supply of power (etching power) from the bias power supply 41 to the lower electrode 10 is stopped. Consequently, the etching of the substrate W in the processing chamber CH is stopped.
The fourth modification of the embodiment is similar to the embodiment in that the power supply circuit 40 transmits a synchronization signal to the power supply circuit 60 via the control line 90 in response to the stop of power supply, and the power supply circuit 60 transmits a synchronization signal to the power supply circuit 40 via the control line 90 in response to the stop of power supply.
In such a manner, in the substrate processing apparatus 201, the power supply circuit 40 and the power supply circuit 60 also transmit and receive, via the control line 90, a synchronization signal related to at least one of the supply of power (sputtering power) by the power supply circuit 40 and the supply of power (etching power) by the power supply circuit 60. In response to the synchronization signal, the power supply circuit 40 and the power supply circuit 60 synchronize the power supply by the power supply circuit 40 and the power supply by the power supply circuit 60. Thus, it is possible to alternately perform etching and film formation (for example, sputtering) while maintaining the supply of the same processing gas into the processing chamber CH, and therefore it is possible to efficiently perform etching processing for a plurality of closely arranged hole patterns that are difficult to mask with a resist pattern, for example. In other words, the substrate W can be efficiently processed.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-151496 | Sep 2021 | JP | national |
