JP2022102856A - Plasma processing device and plasma processing method - Google Patents

Abstract

To improve processing performance.SOLUTION: A plasma processing device includes a first electrode or an antenna, a second electrode that opposes to the first electrode or the antenna and supports a substrate, a first high-frequency electric power supply portion that is connected to the first electrode, the second electrode, or the antenna, and supplies a first high-frequency electric power for generating plasma to the first electrode, the second electrode or the antenna, a second high-frequency electric power supply portion that is connected to the second electrode, and supplies a second high-frequency electric power for bias to the second electrode, a processed gas supply portion that supplies processed gas, and a control portion. The control portion sequentially outputs the first high-frequency electric power of first, second and third levels that are different 0 or more levels from the first high-frequency electric power supply portion repeatedly, simultaneously outputs the first high-frequency electric power of the first level from the first high-frequency electric power supply portion and the second high-frequency electric power of a fourth level that is 0 or more from the second high-frequency electric power supply portion, and turns off the second high-frequency electric power of the fourth level after outputting the first high-frequency electric power of the second level.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a plasma processing apparatus and a plasma processing method.

Patent Document 1 proposes a plasma processing method in which a pulse wave of high-frequency power for plasma generation and a pulse wave of high-frequency power for biasing a frequency lower than the frequency of high-frequency power for plasma generation are applied to a mounting table. do. In this plasma processing method, the pulse wave of the high frequency power for plasma generation and the pulse wave of the high frequency power for bias have a phase difference, and the duty ratio of the high frequency power for plasma generation is the duty ratio of the high frequency power for bias. Control so that it becomes the above. As a result, an offset is provided between the high-frequency power pulse wave for plasma generation and the high-frequency power pulse wave for bias.

Japanese Unexamined Patent Publication No. 2016-157735

It is important to finely control radicals, ion densities, ion incident angles, side wall protection, etc. in order to suppress or improve the bowing of etched recesses, variation in CD size, distortion and clogging of masks, etc. be.

The present disclosure provides techniques that can improve the performance of processes performed in plasma processing equipment.

According to one aspect of the present disclosure, a processing chamber capable of vacuum exhaust, a first electrode or an antenna arranged in the processing chamber, and facing the first electrode or the antenna to support a substrate to be processed. A first high frequency that is connected to the first electrode, the first electrode, the second electrode, or the antenna, and supplies the first high frequency power for plasma generation to the first electrode, the second electrode, or the antenna. A power supply unit, a second high-frequency power supply unit connected to the second electrode and supplying a second high-frequency power for bias to the second electrode, and a processing gas for supplying processing gas into the processing chamber. The control unit includes a supply unit, a control unit that controls the first high-frequency power supply unit and the second high-frequency power supply unit, and the control unit has a different level of 0 or more from the first high-frequency power supply unit. The first high-frequency power of the first level, the second level, and the third level are repeatedly output in order, and the first high-frequency power of the first level is output from the first high-frequency power supply unit. At the same time as outputting the power, the second high frequency power of 0 or more at the fourth level is repeatedly output from the second high frequency power supply unit, and the second level of the second high frequency power supply unit outputs the power. Provided is a plasma processing apparatus that controls to turn off the second high frequency power of the fourth level after outputting the high frequency power of 1.

According to one aspect, the performance of the process performed in the plasma processing apparatus can be improved.

The sectional schematic diagram which shows an example of the plasma processing system which concerns on embodiment. The figure which shows an example of the plasma processing method which concerns on 1st Embodiment. The figure which shows an example of the attenuation characteristic such as radicals. The figure which shows an example of the plasma processing method which concerns on 2nd Embodiment. The figure which shows an example of the plasma processing method which concerns on 3rd Embodiment. The figure which shows an example of the plasma processing method which concerns on 4th Embodiment. The figure which shows an example of the plasma processing method which concerns on 5th Embodiment. The figure which shows an example of the plasma processing method which concerns on 6th Embodiment.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted.

[Plasma processing system]
An example of the configuration of the plasma processing system will be described below. The plasma processing system includes a capacitively coupled plasma processing device 1 and a control unit 2. The plasma processing apparatus 1 includes a plasma processing chamber 10 capable of vacuum exhaust, a gas supply unit 20, a power supply 30, and an exhaust system 40. Further, the plasma processing apparatus 1 includes a substrate support portion 11 and a gas introduction portion. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction section includes a shower head 13. The substrate support portion 11 is arranged in the plasma processing chamber 10. The shower head 13 is arranged above the substrate support portion 11. In embodiments, the shower head 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The inside of the plasma processing chamber 10 has a plasma processing space 10s defined by a shower head 13, a side wall 10a of the plasma processing chamber 10, and a substrate support portion 11. The plasma processing chamber 10 has at least one gas supply port 13a for supplying at least one processing gas to the plasma processing space 10s, and at least one gas discharge port 10e for discharging gas from the plasma processing space. .. The side wall 10a is grounded. The shower head 13 and the substrate support portion 11 are electrically insulated from the housing of the plasma processing chamber 10.

The board support portion 11 includes a main body portion 111 and a ring assembly 112. The main body 111 has a central region (board support surface) 111a for supporting the substrate W, which is an example of a wafer, and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is arranged on the central region 111a of the main body 111, and the ring assembly 112 is arranged on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. In the embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is placed on the base. The upper surface of the electrostatic chuck has a substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Further, although not shown, the substrate support portion 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate W to the target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. Heat transfer fluids such as brine and gas flow through the flow path. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. In addition to the shower head 13, the gas introduction portion may include one or a plurality of side gas injection portions (SGI: Side Gas Injector) attached to one or a plurality of openings formed in the side wall 10a.

The gas supply unit 20 may include at least one gas source 21 and at least one flow rate controller 22. In the embodiment, the gas supply unit 20 is configured to supply at least one processing gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow rate controller 22. Each flow rate controller 22 may include, for example, a mass flow controller or a pressure-controlled flow rate controller. Further, the gas supply unit 20 may include one or more flow rate modulation devices that modulate or pulse the flow rate of at least one processing gas.

The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive member of the substrate support 11 and / or the conductive member of the shower head 13. Will be done. As a result, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power supply 31 may function as at least part of a plasma generator configured to generate plasma from one or more treated gases in the plasma processing chamber 10. Further, by supplying the bias RF signal to the conductive member of the substrate support portion 11, a bias potential is generated in the substrate W, and the ionic component in the formed plasma can be drawn into the substrate W.

In an embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the conductive member of the substrate support portion 11 or the conductive member of the shower head 13 via at least one impedance matching circuit, and is a source RF signal (source RF power) for plasma generation. Is configured to generate. In embodiments, the source RF signal has frequencies in the range of 13 MHz to 150 MHz. In an embodiment, the first RF generator 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support 11 or the conductive member of the shower head 13. The second RF generation unit 31b is coupled to the conductive member of the substrate support portion 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In embodiments, the bias RF signal has a lower frequency than the source RF signal. In embodiments, the bias RF signal has frequencies in the range of 400 kHz to 13.56 MHz. In embodiments, the second RF generator 31b may be configured to generate a plurality of bias RF signals with different frequencies. The generated bias RF signal is supplied to the conductive member of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

The conductive member of the shower head 13 is an example of the first electrode arranged in the plasma processing chamber 10. An inductively coupled plasma processing apparatus may be included in place of the capacitively coupled plasma processing apparatus 1. In an inductively coupled plasma processing apparatus, an antenna is provided on the upper part of the plasma processing chamber 10 facing the first electrode supporting the substrate to be processed, and the first RF generation unit 31a may be connected to the antenna. The conductive member of the base of the support portion 11 is an example of the second electrode facing the first electrode and supporting the substrate to be processed. The first RF generation unit 31a is connected to the first electrode, the second electrode or the antenna, and supplies the first high frequency power for supplying plasma to the first electrode, the second electrode or the antenna. This is an example of the department. The second RF generation unit 31b is an example of a second high-frequency power supply unit that is connected to the second electrode and supplies the second high-frequency power for bias to the second electrode. The gas supply unit 20 is an example of a processing gas supply unit that supplies the processing gas into the plasma processing chamber 10.

Further, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In the embodiment, the first DC generation unit 32a is connected to the conductive member of the substrate support portion 11 and is configured to generate the first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support portion 11. In embodiments, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In the embodiment, the second DC generation unit 32b is connected to the conductive member of the shower head 13 and is configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the shower head 13. In various embodiments, at least one of the first and second DC signals may be pulsed. The first DC generation unit 32a and the second DC generation unit 32b are provided in addition to the RF power supply 31. The second DC generation unit 32b is an example of a DC voltage source connected to the first electrode and supplying a DC voltage to the first electrode.

The exhaust system 40 may be connected to, for example, a gas outlet 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure adjusting valve adjusts the pressure in the plasma processing space 10s. The vacuum pump may include a turbo molecular pump, a dry pump or a combination thereof.

The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various steps described herein. For example, the control unit 2 controls the first RF generation unit 31a, the second RF generation unit 31b, and the second DC generation unit 32b. In the embodiment, a part or all of the control unit 2 may be included in the plasma processing device 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on the program stored in the storage unit 2a2. The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

Next, the plasma processing methods according to the first to sixth embodiments executed by using the plasma processing apparatus 1 will be described in order with reference to FIGS. 2 to 8. The plasma processing method according to the first to sixth embodiments is controlled by the control unit 2.

<First Embodiment>
[Plasma processing method]
First, the plasma processing method according to the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing an example of the plasma processing method according to the first embodiment. FIG. 3 is a diagram showing an example of attenuation of radicals and the like.

In the first embodiment and the second and fifth embodiments described later, for example, a hard mask layer is formed as an etching target film 101 on a silicon substrate 100, and a mask 102 such as an organic film is formed on the hard mask layer. .. However, the film structure on the substrate W is not limited to this.

In the plasma processing method according to the first embodiment, as shown in FIG. 2, the control unit 2 sets the first high frequency power for plasma generation (hereinafter, also referred to as “HF”) to 0 or more different 3 The RF pulse patterns of the first level, the second level, and the third level, which are the levels, are controlled to be repeatedly output in order.

The first level of HF is controlled to the High level output during period A, which is the first period of each cycle. The second level of HF is controlled to the Middle level output in the B period following the A period of each cycle. The HF of the third level is controlled to the Low level output in the C period and the D period following the B period of each cycle. That is, in the present embodiment, the magnitude of the HF is 1st level> 2nd level> 3rd level. Instead of controlling the HF to the Low level during the C period and the D period, it may be turned off. The Low level is a value larger than off and is the lowest level among the levels under which HF is controlled.

Further, the control unit 2 controls the second high frequency power for bias (hereinafter, also referred to as “LF”) so as to repeatedly output the pulse pattern of the fourth level RF of 0 or more. The LF of the fourth level is controlled to the Low level output during the D period of each cycle. During the period A to C, the LF is controlled to be off, that is, to 0. The LF may be turned off during the D period. The Low level is a value greater than off and is the lowest of the levels for which LF is controlled.

For example, when the HF is controlled to two levels of on and off and the LF is controlled to one level of only off, the CD (Critical Dimension) size varies and a good etching shape cannot be obtained. On the other hand, in the RF pulse pattern according to the present embodiment, the HF is controlled to three levels of High, Middle, Low, or High, Middle, 0 (off), and the LF is Low and 0 (off). It is controlled to 2 levels.

Further, when the HF is High and Middle (first level and second level), the LF is controlled to be off, and when the HF is Low (third level), the LF is controlled to be Low (or off). .. Further, the Duty of the HF power and the LF power and the phase when the HF power and the LF power are supplied are controlled, and the phase of the HF power and the LF power is shifted. Further, an off time (including the case where HF and / or LF is Low) is provided in the C period between the A period and B period of HF High and Midle and the D period of LF Low.

This makes it possible to finely control the radical density, ion density, ion / radical ratio, ion incident angle (ion incident angle), side wall protection, and the like. As a result, it is possible to suppress boeing of recesses such as etched holes H, variation of CDs, and clogging of masks, form a desired shape in a desired time, and improve process performance.

Specifically, in the plasma treatment method according to the first embodiment, the HF of the first level (High power) is applied in the A period, and the LF is off. Therefore, HF contributes to the generation of ions and radicals. Therefore, in the A period, as shown in FIG. 2A, the ion energy is high and the etching rate is high. In addition, the angle of incidence of the ions is relatively narrow, and etching tends to proceed vertically. However, the damage to the mask 102 becomes large.

In period B, the ratio of radicals to ions in the plasma is controlled. The HF is lowered from the first level (High power) to the second level (Middle power), and the LF remains off. As a result, in the B period, the generation of ions and radicals is reduced as compared with the A period, and in particular, the ion energy is lowered, and cogging and mask damage are suppressed. Along with this, as shown in FIG. 2B, the reaction products (including By-product and by-products generated by etching) are reduced, and the film to be etched is reduced while reducing the clogging of the mask 102 and the damage of the mask 102. Etching of 101 can be promoted.

In period C, the HF is lowered from the second level (Middle power) to the third level (Low power), and the LF remains off. As a result, in the C period, the ion energy is small by utilizing the difference between the decay times of the ions and the radicals, and the damage of the mask 102 is reduced.

FIG. 3 shows the attenuation characteristics of electrons, ions and radicals. The horizontal axis of FIG. 3 is time, and the vertical axis is the normalized amount of attenuation. When the RF power (HF) is switched from on to off, the plasma temperature first drops sharply. Next, the ions (Plasma Density) are attenuated. In contrast, radical decay is gradual.

As described above, the electron temperature and the ions decay relatively rapidly, while the radical decays relatively slowly. Therefore, in the C period, the ratio of the radicals to the ions increases, and the effect of protecting the side wall becomes superior. In addition, the side wall protection can be appropriately maintained by exhausting excess components and reaction products.

As a result, in the C period and the D period, the ratio of ions in the plasma is further reduced as compared with the B period, and the amount of the reaction product is relatively large. Therefore, as shown in FIG. 2C, the reaction product adheres to the side wall of the hole H and the side wall of the mask 102 to form the protective film 103. The protective film 103 may be formed on the upper part of the mask 102. This makes it possible to prevent distortion of the mask shape and deterioration of the mask 102 due to the mask 102 becoming too thin. In addition, the exhaust of reaction products can be controlled.

In the D period, the HF of the third level is maintained, and the LF of the fourth level of 0 or more of Low (or off) is output in the period until the HF of the first level is output. By controlling the LF to Low, as shown in FIG. 2D, ions are drawn into the hole H, removing the clogging G of the mask 102, and protecting the side wall by forming the protective film 103 and the reaction product. Exhaust of (by-product) can be controlled.

The HF and LF pulse patterns are repeatedly executed with the period A to D described above as one cycle. By controlling the combination of HF and LF pulse patterns and the distribution of each power for each period in this way, the ratio of radicals to ions, plasma density, ion energy, etc. can be controlled. This makes it possible to improve the Boeing of the etched recesses, the variation of the CD, the clogging of the mask 102, the distortion of the mask 102, and the like.

For example, when the HF is controlled to High or Middle as in the A period and the B period, the ion energy is high. In this case, when the ions collide with the side wall, etching is promoted. On the other hand, when the HF is controlled to Low or Off as in the C period and the D period, the ion energy is low. In this case, even if the ions collide with the side wall, the ions are reflected by the wall and reach the bottom of the etched recess because there is not enough energy to scrape the side wall. This improves the CD at the bottom of the recess.

That is, in the C period and the D period, the side wall protection by the reaction product can be promoted by the decrease in the ion energy, and the exhaust of the excess reaction product can be promoted as well. In particular, when both HF and LF are turned off, the exhaust angle of extra components and reaction products can be controlled, and the incident angle of ions can be controlled by reducing the electron temperature.

In the C period and the D period, when the HF is controlled to Low, the pulse control of the HF and LF can be stabilized without the plasma disappearing as compared with the case where the HF is controlled to be off. In the C period and the D period, when HF is controlled to be off, a radical-rich plasma state in which the ratio of radicals to ions is higher is obtained due to the difference in decay time in FIG. 3 as compared with the case where HF is controlled to Low, and the protective film 103 It is possible to promote the protection of the side wall by the wind.

That is, when HF is off, it becomes radical rich due to the difference in decay time between the ion and electron temperature and the radical. As shown in FIG. 3, the lightest electron has the fastest decay speed. Next, the plasma (ion) is attenuated, the radical is the most difficult to attenuate, and the ion and electron temperature and the radical exist for the longest time. The difference in decay time can be used to control the ion / radical ratio.

By controlling the LF to Low in the D period, the reflection probability of ions and radicals on the surface of the mask 102 increases due to the decrease in ion energy. Therefore, the number of ions and radicals that enter the inside of the etching is reduced, the number of ions and radicals that reach the bottom of the recess is increased, and the variation of the CD at the bottom is improved. Further, by controlling the LF to Low, etching becomes possible while lowering the ion energy.

<Second Embodiment>
[Plasma processing method]
Next, the plasma processing method according to the second embodiment will be described with reference to FIG. FIG. 4 is a diagram showing an example of the plasma processing method according to the second embodiment. In the second embodiment, only the processing different from the plasma processing method according to the first embodiment will be described, and the description of the same processing will be omitted.

In the plasma treatment method according to the first embodiment, the HF of the second level in the B period was controlled to be smaller than the HF of the first level in the A period. On the other hand, in the plasma processing method according to the second embodiment, as shown in FIG. 4, the HF of the second level in the B period is controlled to be larger than the HF of the first level in the A period. .. The control of the C period and the D period of the HF and the control of the LF are the same as those in the first embodiment.

As a result, the formation of the protective film 103 is promoted during the C period, and the side wall can be protected.

As an example of selection of the plasma treatment method of the first embodiment and the plasma treatment method of the second embodiment, either one may be selected depending on the film thickness and film quality of the etching target film 101 and the mask 102. For example, when the mask 102 is relatively hard, the plasma treatment method of the first embodiment may be used, and when the mask 102 is relatively soft, the plasma treatment method of the second embodiment may be used. This makes it possible to control radicals, ion densities, ion incident angles, side wall protection, etc. that match the film structure on the substrate W, suppress boeing, CD variation, mask clogging, etc., and perform vertical etching. It can be done efficiently. However, the method for selecting the plasma processing method of the first embodiment and the plasma processing method of the second embodiment is not limited to this.

<Third Embodiment>
[Plasma processing method]
Next, the plasma processing method according to the third embodiment will be described with reference to FIG. FIG. 5 is a diagram showing an example of the plasma processing method according to the third embodiment.

In the third embodiment and the fourth embodiment described later, for example, SiO ₂ (silicon oxide film) is formed as the etching target film 101 on the silicon substrate 100, and a mask 102 such as a resist film is formed on the SiO 2 (silicon oxide film). .. However, the film structure on the substrate W is not limited to this.

In the plasma processing method according to the third embodiment, as shown in FIG. 5, the control unit 2 sets the HF at three different levels of 0 or more, that is, a first level, a second level, and a third level. It is controlled so that it is repeatedly output in order by the pulse pattern of RF.

The first level of HF is controlled to High, which is output during period A, which is the first period of each cycle. The second level of HF is controlled by the Middle that is output during the B and C periods following the A period of each cycle. The third level of HF is controlled by the Low output during the D period following the C period of each cycle. That is, in the present embodiment, the HF is controlled so that the first level> the second level> the third level, as in the first embodiment. The HF may be turned off during the D period.

Further, the control unit 2 controls the LF to be repeatedly output with a pulse pattern of a fourth level RF of 0 or more. In the present embodiment, the fourth level LF is output in the A period and the B period of each cycle and is controlled to High. LF is turned off during the C period and the D period.

In addition, in the present embodiment, during the A period and the B period in which the LF of the fourth level is applied, the first negative voltage (-V1) is applied to the conductive member of the shower head 13 from the second DC generation unit 32b. ) Is applied. During the C period and the D period, the second negative voltage (−V2) from the second DC generation unit 32b is controlled to be applied. The absolute value of the second negative voltage (-V2) is larger than the absolute value of the first negative voltage (-V1). The first negative voltage may be 0 (off).

In the plasma processing method according to the third embodiment, HF and LF are controlled to High during the A period. As a result, as shown in FIG. 5A, the HF mainly contributes to the generation of ions and radicals, and the LF mainly narrows the angle of incidence of the ions, enabling vertical etching of the hole H.

During the B period, the LF maintains High and the HF is lowered to Middle, thereby lowering the radical density and increasing the ion / radical ratio, as shown in FIG. 5 (b). As a result, the etching rate is maintained high, and the corners of the shape I of the mask 102 are removed to control the clogging of the mask.

Further, during the A period and the B period, cations are driven into the shower head 13 by applying a first negative voltage (−V1) from the second DC generation unit 32b to the conductive member of the shower head 13. .. As a result, secondary electrons are generated from the shower head 13, the secondary electrons reach the bottom of the hole H (recess), and the charge charge by the cations accumulated in the bottom can be canceled. As described above, by applying the first negative voltage (-V1) to the conductive member of the shower head 13 in addition to the LF, the electron density is increased and the bottom of the hole H is charge-cancelled (the bottom of the hole H). (Neutralize the charge).

During the C period, the HF maintains the Middle, controls the LF to be off, and applies a second negative voltage (-V2) from the second DC generation unit 32b, as shown in FIG. 5 (c). Control the radical ratio to ions and increase the ratio of radicals. As a result, the reaction product is attached to the mask 102 to eliminate the distortion of the mask 102 and improve the shape I of the mask 102. The first negative voltage (-V1) and the second negative voltage (-V2) are examples of the first DC voltage.

During the D period, the LF is kept off, the HF is controlled to Low (or off), and the second negative voltage (-V2) from the second DC generation unit 32b is applied. As a result, the electron temperature and ions decay relatively rapidly, while the radical decays relatively slowly, so that the ratio of ions in the plasma decreases, the ion energy decreases, and the amount of reaction products increases. Therefore, the reaction product adheres to the side wall of the hole H and the side wall and the upper part of the mask 102 to form the protective film 103. In addition, the extra components and by-products generated during etching are exhausted, so that the side wall protection can be appropriately maintained.

In the C period and the D period, a second negative voltage (−V2) is applied to the conductive member of the shower head 13 from the second DC generation unit 32b. In this way, by applying a larger negative voltage from the second DC generator 32b in synchronization with the LF off period, the electron density of the plasma and the incident angle of the ions can be controlled, and a larger charge can be canceled (Hall H). Can contribute to (neutralize the bottom of the).

<Fourth Embodiment>
[Plasma processing method]
Next, the plasma processing method according to the fourth embodiment will be described with reference to FIG. FIG. 6 is a diagram showing an example of the plasma processing method according to the fourth embodiment. In the fourth embodiment, only the processing different from the plasma processing method according to the third embodiment will be described, and the description of the same processing will be omitted.

In the plasma processing method according to the third embodiment, the LF of the fourth level was turned off during the period when the HF of the second level was output. On the other hand, in the plasma processing method according to the fourth embodiment, the LF of the fourth level is controlled to be turned off during the period when the HF of the third level is output.

That is, the control of HF, LF, and DC in the A period, B period, and D period shown in FIG. 6 is the same as the control of each of the A period, B period, and D period shown in FIG. Only the control of DC is the opposite of the control of the third embodiment. Specifically, the HF in the C period is controlled to Low (or off), the LF in the C period is controlled to High following the B period, and the DC in the C period is controlled to the first negative voltage (-V1). To.

As a result, in the C period shown in FIG. 5 (c), the ratio of radicals to ions was increased to make the reaction product rich, but in the C period shown in FIG. 6 (c), the ratio of radicals to ions was decreased. To make it a state without reaction products.

For example, when boeing is generated on the side wall of the hole H, the plasma treatment method according to the third embodiment is applied to protect the mask 102 while suppressing boeing by making the reaction product rich in the C period. Is preferable.

On the other hand, for example, when there is no problem in the shape of the mask 102 and it is desired to increase the ion energy as much as possible to increase the etching rate, the plasma treatment method according to the fourth embodiment is applied, and a reaction product-free state is applied during the C period. It is preferable to increase the etching rate. This can improve the throughput.

<Fifth Embodiment>
[Plasma processing method]
Next, the plasma processing method according to the fifth embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram showing an example of the plasma processing method according to the fifth embodiment. In the fifth embodiment, only the processing different from the plasma processing method according to the fourth embodiment will be described, and the description of the same processing will be omitted.

In the plasma treatment method according to the fourth embodiment, HF and LF were controlled to High during the A period. On the other hand, in the plasma processing method according to the fifth embodiment, the phases of HF and LF are shifted. That is, the LF of the first level and the HF of the second level are lowered (or turned off), and then the LF of the fourth level (High) is output.

When HF and LF are superposed and supplied, the ion energy becomes high and the damage to the mask 102 becomes large. On the other hand, when the phases of HF and LF are out of phase as in the present embodiment, the ion energy can be controlled, and the shape of the mask 102 is as shown in FIGS. 7 (a) to 7 (c) during the period A to C. Can be kept good. In the A period and the B period, the ratio of radicals to ions is controlled by controlling the HF to High or Middle, and the shape of the mask 102 and the clogging of the mask 102 are controlled.

In the off section of the C period, the electron temperature drops at once (see plasma potential ( _Te ) in FIG. 3). Utilizing this, the diffusion of electrons and cations is suppressed in the off-section of the C period. The incident angle of the ions in the subsequent D period is narrowed, and verticality can be ensured. Further, in the C period, the lowering of the ion energy promotes the protection of the side wall by the protective film 103.

By controlling the LF to High during the D period, the reaction product-less state is achieved by the action of the LF, the incident angle of the ions is narrowed, and the hole H can be vertically etched.

In the period A to C, the second negative voltage (-V2) is applied from the second DC generation unit 32b, and in the period D, the first negative voltage (-V1) is applied from the second DC generation unit 32b. Is applied. In this way, by changing the magnitude of the negative voltage in synchronization with the control of the LF, it is possible to contribute to the control of the electron density of the plasma and the incident angle of the ions and the charge cancellation.

<Sixth Embodiment>
[Plasma processing method]
Next, the plasma processing method according to the sixth embodiment will be described with reference to FIG. 8 (a) and 8 (b) are diagrams showing an example of the plasma processing method according to the sixth embodiment. In the plasma treatment method according to the sixth embodiment of FIG. 8A, the HF and LF are turned off during the A period and the B period as compared with the plasma treatment method according to the first embodiment of FIG. There is. There is also an F period during which the HF and LF are turned off between the D period and the A period of the next cycle.

Further, in the plasma treatment method according to the sixth embodiment of FIG. 8B, HF and LF are turned off during the period A and the period B as compared with the plasma treatment method according to the third embodiment of FIG. There is an E period. There is also an F period during which the HF and LF are turned off between the D period and the A period of the next cycle.

That is, in the plasma processing method according to the sixth embodiment, it is controlled to provide a period for turning off the HF and the LF after the output period of the LF of the fourth level and before the output period of the HF of the first level. You may.

Further, in the plasma processing method according to the sixth embodiment, it is controlled to provide a period for turning off HF and LF after the output period of the first level HF and before the output period of the second level HF. You may.

During the E period and the F period when the HF and LF are turned off, it is possible to promote the protection of the side wall by lowering the ion energy and the promotion of exhaust gas. The period for turning off HF and LF may be at least one of the E period and the F period. Further, the E period and the F period may be controlled so that the HF and / or the LF is turned off or low.

[Common matters in the first, second, and fifth embodiments]
The HF and / or LF control options common to the first, second, and fifth embodiments will be described. The fourth level LF of the D period of the first, second and fifth embodiments is smaller than the first level HF of the A period of the first, second and fifth embodiments, and the B period It may be controlled to be smaller than the second level HF.

The fourth level LF of the D period may be controlled to be smaller than the first level HF of the A period and larger than the second level HF of the B period.

The first level HF of the A period may be controlled to be smaller than the LF of the fourth level of the D period and larger than the HF of the second level of the B period.

The output period of the fourth level LF may be controlled to be shorter than the output period of the third level HF.

The output period of the fourth level LF may be controlled to be longer than the output period of the third level HF.

A DC voltage may be applied from the second DC generator 32b during the output period of the fourth level LF. The DC voltage may be a negative voltage.

[Common matters in the third and fourth embodiments]
The HF and / or LF control options common to the third and fourth embodiments will be described. The fourth level LF of the third and fourth embodiments may be controlled to be turned off during the period when the second level HF is output.

The LF of the 4th level may be controlled to be turned off during the period when the HF of the 3rd level is output.

The LF of the fourth level may be controlled to be smaller than the HF of the first level and the HF of the second level.

The LF of the fourth level may be controlled to be smaller than the HF of the first level and larger than the HF of the second level.

The HF of the first level may be controlled to be smaller than the LF of the fourth level and larger than the HF of the second level.

The output period of the fourth level LF may be controlled to be shorter than the total output period of the first level and the second level HF.

The output period of the fourth level LF may be controlled to be longer than the total output period of the first level and the second level HF.

A DC voltage may be applied from the second DC generator 32b during the output period of the fourth level LF. The DC voltage may be a negative voltage.

As described above, according to the plasma processing apparatus and the plasma processing method of the present embodiment, the performance of the process can be improved.

It should be considered that the plasma processing apparatus and the plasma processing method according to the embodiment disclosed this time are exemplary in all respects and are not restrictive. The embodiments can be modified and improved in various forms without departing from the scope of the appended claims and their gist. The matters described in the plurality of embodiments may have other configurations within a consistent range, and may be combined within a consistent range.

The plasma processing apparatus of the present disclosure is not limited to Capacitively Coupled Plasma (CCP), but is limited to Inductively Coupled Plasma (ICP), Atomic Layer Deposition (ALD) apparatus, Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), Helicon. Applicable to any type of device of Wave Plasma (HWP).

1 Plasma processing device 2 Control unit 2a Computer 2a1 Processing unit 2a2 Storage unit 2a3 Communication interface 10 Plasma processing chamber 11 Board support unit 13 Shower head 21 Gas source 20 Gas supply unit 30 Power supply 31 RF power supply 31a First RF generation unit 31b First 2 RF generation unit 32a 1st DC generation unit 32b 2nd DC generation unit 40 Exhaust system 100 Silicon substrate 101 Etching target film 102 Mask 111 Main body 112 Ring assembly

Claims (13)

With a processing chamber that can be evacuated
With the first electrode or antenna arranged in the processing chamber,
A second electrode facing the first electrode or the antenna and supporting the substrate to be processed, and a second electrode.
A first high-frequency power supply unit connected to the first electrode, the second electrode, or the antenna and supplying the first high-frequency power for plasma generation to the first electrode, the second electrode, or the antenna.
A second high-frequency power supply unit connected to the second electrode and supplying a second high-frequency power for bias to the second electrode,
A processing gas supply unit that supplies processing gas into the processing chamber,
A control unit for controlling the first high-frequency power supply unit and the second high-frequency power supply unit is provided.
The control unit
The first high frequency power of 0 or more different levels, the first level, the second level, and the third level, is repeatedly output from the first high frequency power supply unit in order.
The first high-frequency power of the first level is output from the first high-frequency power supply unit, and at the same time, the second high-frequency power of 0 or more at the fourth level is repeated from the second high-frequency power supply unit. Output and
A plasma processing apparatus that controls to turn off the second high-frequency power of the fourth level after outputting the first high-frequency power of the second level from the first high-frequency power supply unit. The control unit controls the second high frequency power of the fourth level to be turned off during the period when the first high frequency power of the second level is output.
The plasma processing apparatus according to claim 1. The control unit controls the second high frequency power of the fourth level to be turned off during the period when the first high frequency power of the third level is output.
The plasma processing apparatus according to claim 1. The control unit makes the second high frequency power of the fourth level smaller than the first high frequency power of the first level and the first high frequency power of the second level. Control,
The plasma processing apparatus according to any one of claims 1 to 3. The control unit makes the second high frequency power of the fourth level smaller than the first high frequency power of the first level and smaller than the first high frequency power of the second level. Control to grow,
The plasma processing apparatus according to any one of claims 1 to 3. The control unit makes the first high frequency power of the first level smaller than the second high frequency power of the fourth level and smaller than the first high frequency power of the second level. Control to grow,
The plasma processing apparatus according to any one of claims 1 to 3. The control unit controls the output period of the second high-frequency power of the fourth level to be shorter than the total output period of the first high-frequency power of the first level and the second level. do,
The plasma processing apparatus according to any one of claims 1 to 6. The control unit controls the output period of the second high-frequency power of the fourth level to be longer than the total output period of the first high-frequency power of the first level and the second level. do,
The plasma processing apparatus according to any one of claims 1 to 6. Further, a DC voltage source connected to the first electrode and supplying a DC voltage to the first electrode is provided.
The control unit controls to apply a first DC voltage from the DC voltage source during the output period of the second high frequency power of the fourth level.
The plasma processing apparatus according to any one of claims 1 to 8. The DC voltage is a negative voltage.
The plasma processing apparatus according to claim 9. The control unit performs the first high frequency power and the first high frequency power after the output period of the second high frequency power of the fourth level and before the output period of the first high frequency power of the first level. Control to provide a period during which the second high frequency power is turned off or at the lowest of the controlled levels.
The plasma processing apparatus according to any one of claims 1 to 10. The control unit performs the first high frequency power and the first high frequency power after the output period of the first high frequency power of the first level and before the output period of the first high frequency power of the second level. Control to provide a period during which the high frequency power of 2 is turned off or at the lowest of the controlled levels.
The plasma processing apparatus according to any one of claims 1 to 11. With a processing chamber that can be evacuated
With the first electrode or antenna placed in the processing chamber,
A second electrode facing the first electrode or the antenna and supporting the substrate to be processed, and a second electrode.
A first high-frequency power supply unit connected to the first electrode, the second electrode, or the antenna and supplying the first high-frequency power for plasma generation to the first electrode, the second electrode, or the antenna.
A second high-frequency power supply unit connected to the second electrode and supplying a second high-frequency power for bias to the second electrode,
A plasma processing method executed by a plasma processing apparatus including a processing gas supply unit for supplying processing gas into the processing chamber.
The first high frequency power of 0 or more different levels, the first level, the second level, and the third level, is repeatedly output from the first high frequency power supply unit in order.
The first high-frequency power of the first level is output from the first high-frequency power supply unit, and at the same time, the second high-frequency power of 0 or more at the fourth level is repeated from the second high-frequency power supply unit. Output and
A plasma processing method in which the second high-frequency power of the second level is output from the first high-frequency power supply unit and then the second high-frequency power of the fourth level is turned off.

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