Substrate processing method

Abstract

To provide a substrate processing method capable of reducing particles in a chamber.SOLUTION: A method of processing a substrate in a substrate processing apparatus including a chamber, an upper coil generating plasma inside the chamber, and an electrostatic chuck, the method comprising: supplying plasma into the chamber; and depositing a hard mask thin film on an upper surface of the substrate, wherein a voltage is applied to a bias electrode provided in the electrostatic chuck in a predetermined waveform in the depositing the hard mask thin film. Wherein the waveform includes a first section having a predetermined positive value, and a second section which is switched to a predetermined negative value at an end of the first section and includes a slope having a predetermined gradient, and is switched to the predetermined positive value at an end of the second section, and the first section and the second section are repeated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method, and more particularly to a substrate processing method capable of reducing particles in a chamber of a substrate processing apparatus that deposits a hard mask thin film on a substrate using inductively coupled plasma in a low-temperature process. [Background technology]

[0002] In general, amorphous carbon layers are used in a wide range of fields, including biomaterials, organic light-emitting diodes (OLEDs), semiconductor integrated circuits, solar cells, OLED touch panels, and hard masks.

[0003] In particular, in the field of semiconductors, where miniaturization and high integration are progressing, ever smaller patterns are required, and amorphous carbon films for hard masks are used to form such small patterns.

[0004] To address the problem of pattern realization that can occur under low selectivity when using conventional amorphous carbon films as hard mask films, methods have been developed to improve the selectivity of thin films by increasing the process temperature, to use inductively coupled plasma (ICP) with high plasma density instead of capacitively coupled plasma (CCP), or to improve the quality by applying new precursors.

[0005] However, when high-temperature processes are used, there is a risk of reducing the durability of chamber parts and causing thermal damage when connecting to subsequent processes. In addition, there is a risk of additional processes being required to solve the problem of metal contamination in the chamber. Therefore, there is a need to develop a hard mask that can be used in low-temperature processes.

[0006] However, when forming an amorphous carbon film using a low-temperature process, an inductively coupled plasma method is preferable because it has a lower selectivity and uses higher energy than conventional hard masks. However, when using a low-temperature process, there is a risk of particle generation problems in the chamber. For this reason, there is a growing need for the development of a technology that can reduce particle generation when depositing an amorphous carbon film using an inductively coupled plasma method in a low-temperature process. Summary of the Invention [Problem to be solved by the invention]

[0007] In order to solve the above-mentioned problems, an object of the present invention is to provide a substrate processing method that can minimize particle generation in a chamber when depositing a hard mask thin film made of an amorphous carbon film on a substrate using a low-temperature process. [Means for solving the problem]

[0008] The above-described objects of the present invention can be achieved by a substrate processing method for a substrate processing apparatus including a chamber, an upper coil disposed above the chamber to generate plasma inside the chamber, and an electrostatic chuck disposed inside the chamber, the method including: supplying plasma into the chamber; and depositing a hard mask thin film on an upper surface of the substrate, wherein, in the step of depositing the hard mask thin film, a voltage having a predetermined waveform is applied to a bias electrode of the electrostatic chuck, the waveform including a first section having a predetermined positive value and a second section having a predetermined slope, the second section being switched to a predetermined negative value at an end of the first section, and the waveform being switched to the predetermined positive value at an end of the second section, and the first and second sections being repeated. [Effects of the Invention]

[0009] According to the present invention having the above-mentioned configuration, when a hard mask thin film made of an amorphous carbon film is vapor-deposited on a substrate by a low-temperature process, particles in the chamber can be minimized. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side cross-sectional view showing an internal configuration of a substrate processing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a flowchart showing a substrate processing method according to the present invention; [Figure 3] 10 is a graph comparing the number of particles adsorbed to a substrate when a process is performed using the substrate processing method of the present invention with the number of particles adsorbed to a substrate when a process is performed using a substrate processing method according to conventional technology. [Figure 4] 10 is a graph comparing the number of particles adsorbed to a substrate when a process is performed using the substrate processing method of the present invention with the number of particles adsorbed to a substrate when a process is performed using a substrate processing method according to conventional technology. [Figure 5] 10 is a graph comparing the number of particles adsorbed to a substrate when a process is performed using the substrate processing method of the present invention with the number of particles adsorbed to a substrate when a process is performed using a substrate processing method according to conventional technology. [Figure 6] 10 is a graph showing a case where a voltage is applied to a bias electrode by a bias power supply according to the prior art. [Figure 7] 4 is a graph showing the application of a voltage to a bias electrode by a bias power supply according to the present invention. [Figure 8] 8 is a graph showing in more detail the waveform of the voltage applied from the bias power supply shown in FIG. 7; [Figure 9] 9 is a graph showing the ion energy distribution function (IEDF) of ions (Ion) due to plasma inside the chamber when the voltage waveform shown in FIG. 8 is applied. [Figure 10] 8 is a graph showing various properties of an amorphous carbon film when the amorphous carbon film is deposited according to the embodiment shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the structure of a substrate processing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings, and then a substrate processing method will be described.

[0012] FIG. 1 is a side cross-sectional view showing the internal configuration of a substrate processing apparatus 1000 according to one embodiment of the present invention.

[0013] Referring to FIG. 1, the substrate processing apparatus 1000 may include a chamber 100 providing a processing space 110 for a substrate, an upper coil 130 disposed in the upper portion of the chamber 100 and receiving RF power from RF power supplies 132 and 136 to generate plasma in the processing space 110, and an electrostatic chuck 300 disposed inside the chamber 100 on which the substrate W is placed and fixed.

[0014] The substrate processing apparatus 1000 according to the present invention may correspond to, for example, an apparatus for depositing a hard mask thin film on the upper surface of the substrate W. The hard mask thin film may be made of an amorphous carbon layer or the like. The substrate processing apparatus 1000 may also use inductively coupled plasma (ICP) to deposit the hard mask thin film. Furthermore, the process of depositing the hard mask thin film made of an amorphous carbon film is a low-temperature process, and the interior of the chamber 100 may have a temperature of, for example, approximately -20°C to 100°C.

[0015] On the other hand, the higher the sp3 bond composition of carbon in the amorphous carbon film, the higher the etching selectivity of the hard mask thin film in subsequent photo processes, etc. However, as the ion energy of inductively coupled plasma increases, the carbon bond changes from sp3 to sp2, decreasing the proportion of the sp3 composition.

[0016] In the present invention, the upper coil 130 controls high-density plasma in the processing space 110, and the bias electrode 332 disposed in the electrostatic chuck 300 controls ions in the processing space 110 to adjust ion energy. Therefore, in the substrate processing apparatus 1000, the bias electrode 332 controls ions in the processing space 110 to adjust the ion energy, thereby increasing the sp3 bond composition of carbon in the amorphous carbon film. This will be described in detail below.

[0017] The chamber 100 may provide an internal processing space 110 in which the substrate W is processed and plasma is generated.

[0018] The upper coil 130 is installed at the top of the chamber 100 and can be supplied with power from RF power sources 132 and 136 .

[0019] In this case, the upper coil 130 may be composed of a plurality of coils 130A, 130B spaced apart in the radial direction in the center of the chamber 100. For example, the upper coil 130 may be composed of a first coil 130A disposed in the center of the chamber 100 and a second coil 130B disposed on the outer periphery surrounding the first coil 130A. The number of coils 130A, 130B may be three or more and can be changed as appropriate.

[0020] Meanwhile, the RF power supply sources 132, 136 may be configured to include a first RF supply source 132 that provides RF power to the first coil 130A and a second RF supply source 136 that provides RF power to the second coil 130B. The RF power supply sources 132, 136 may be configured to generate high frequency (HF) power of, for example, 13.56 MHz and provide a power of approximately 500 W to 2000 W.

[0021] The first RF source 132 may include a first matcher 134, and the second RF source 136 may include a second matcher 138 to provide tuned power to the first coil 130A and the second coil 130B, respectively, thereby generating a plasma in the processing space 110.

[0022] Meanwhile, a dielectric window 140 may be provided on the upper part of the chamber 100 to maintain the pressure inside the chamber 100 and to transmit the energy generated in the upper coil 130. The upper coil 130 may be provided on the upper part of the window 140.

[0023] Further, a gas distribution plate 150 may be disposed below the window 140 to supply a process gas to the processing space 110. The gas distribution plate 150 may have a plurality of supply holes (not shown) for supplying a process gas. Therefore, the process gas supplied from the process gas supply source 160 may be supplied to the processing space 110 through the gas distribution plate 150.

[0024] Meanwhile, the chamber 100 may be provided with an exhaust passage 180 for exhausting gases or by-products from within the processing space 110, and the exhaust passage 180 may be provided with an exhaust pump 182. The exhaust passage 180 may also be provided with a pressure control valve (not shown).

[0025] In this case, the exhaust pump 182 may be, for example, a turbo molecular pump, which can realize a low process pressure inside the chamber 100 and increase the mean free path of ions, thereby reducing energy loss due to ion collisions.

[0026] Furthermore, an electrostatic chuck 300 on which the substrate W is placed may be provided inside the chamber 100. The electrostatic chuck 300 may include a chuck electrode 322 that secures the substrate W by electrostatic force, and a bias electrode 332 to which bias power that induces ions in the processing space 110 is supplied.

[0027] For example, the electrostatic chuck 300 may include an upper plate 310 made of a dielectric material, a heating plate 340 disposed below the upper plate 310 to heat the substrate W, and a support plate 360 ​​disposed below the heating plate 340.

[0028] The upper plate 310 may be a flat plate made of a dielectric material, and may be made of at least one ceramic material, such as aluminum oxide (alumina: Al2O3), aluminum nitride, silicon carbide, silicon nitride, and yttrium oxide (yttria: Y2O3), but is not limited thereto.

[0029] The chuck electrode 322 and the bias electrode 332 may be disposed on the upper plate 310. In this case, the chuck electrode 322 may be disposed on the upper portion of the upper plate 310, and the bias electrode 332 may be disposed on the upper plate 310 below the chuck electrode 322. Since the electrostatic force of the chuck electrode 322 gradually increases inversely proportional to the square of the distance as the distance from the substrate W increases, it is preferable that the chuck electrode 322 be disposed above the bias electrode 332 so that the chuck electrode 322 stably holds the substrate W.

[0030] The chucking electrode 322 may be electrically connected to a DC power supply 324. When a DC voltage is applied to the chucking electrode 322 from the DC power supply 324, an electrostatic force is generated between the chucking electrode 322 and the substrate W. The substrate W is held on the upper surface of the upper plate 310 by this electrostatic force.

[0031] Meanwhile, the substrate processing apparatus 1000 may further include a bias power supply 334 that provides RF power to the bias electrode 332 to induce ions in the processing space 110. The bias power supply 334 may be configured to generate low frequency (LF) power of, for example, 360 kHz to 390 kHz and provide a power of approximately 500 W to 2000 W. The low frequency power induces ions in a wide energy range, allowing a hard mask thin film to be deposited on the substrate W.

[0032] The bias power supply 334 may be electrically connected to the bias electrode 332 of the top plate 310 through a third matcher 336 .

[0033] Meanwhile, a heating plate 340 for heating the substrate W may be provided below the upper plate 310. The heating plate 340 may be configured, for example, by incorporating a film heater (not shown). However, the film heater is merely an example and may be configured in various shapes. Bonding layers (not shown) may be provided on the top and bottom of the heating plate 340.

[0034] Furthermore, a support plate 360 ​​may be provided below the heating plate 340. The support plate 360 ​​may be made of a metal such as aluminum. Although the support plate 360 ​​is shown as a single member in the drawings, it is not limited thereto and may be made of two or more members.

[0035] The support plate 360 ​​may include a heat transfer channel 362 through which a heat transfer fluid flows. The heat transfer fluid flowing through the heat transfer channel 362 can adjust the temperature of the support plate 360.

[0036] Meanwhile, the upper plate 310 may have a plurality of grooves 312 formed therein, and the plurality of grooves 312 may be distributed over the upper surface of the upper plate 310 .

[0037] In this case, a gas passage 314 may be formed to penetrate the electrostatic chuck 300 and communicate with the groove 312. That is, the gas passage 314 may be connected to the groove 312 by penetrating the support plate 360, the heating plate 340, and the upper plate 310 from below.

[0038] A cooling gas such as helium (He) can be supplied from the cooling gas source 190 through the gas flow passage 314 and supplied toward the lower surface of the substrate W through the grooves 312 to cool the substrate W.

[0039] In particular, when the substrate W is fixed and held on the upper surface of the upper plate 310 by the chuck electrode 322, the cooling efficiency of the cooling gas supplied through the grooves 312 can be improved. In addition, the bias electrode 332 can prevent the temperature of the substrate W from rising, which may occur when ions in the processing space 110 move toward and collide with the substrate W.

[0040] On the other hand, when an amorphous carbon film is formed using inductively coupled plasma in a low-temperature process as in the present invention, there is a risk of problems with particles in the chamber. Hereinafter, a substrate processing method that can reduce particles in the chamber 100 in the substrate processing apparatus 1000 having the above-mentioned configuration will be described.

[0041] FIG. 2 is a flowchart showing a substrate processing method according to the present invention.

[0042] 1 and 2, the substrate processing method may include a step of supplying plasma into the chamber 100 (S210), a step of depositing a hard mask thin film on an upper surface of the substrate W (S230), and a step of stopping the supply of plasma into the chamber 100 (S250).

[0043] First, the substrate W is loaded into the chamber 100 and placed on the electrostatic chuck 300 .

[0044] Then, argon (Ar) gas is supplied to generate plasma in the processing space 110 through the gas distribution plate 150 , and RF power is supplied to the upper coil 130 .

[0045] In this case, if the target RF power, for example, 1000 W, is immediately supplied to the upper coil 130 from the beginning, the plasma may damage the inner wall of the chamber 100, resulting in the generation of a large number of particles.

[0046] To solve this problem, in the present invention, in the step of supplying plasma into the chamber 100, RF power is supplied to the upper coil 130, and then the RF power is gradually increased.

[0047] Furthermore, when the RF power supplied to the upper coil 130 is gradually increased, the RF power may be increased in stages. For example, a power of 100 W to 300 W may be initially supplied to the upper coil 130, and after a predetermined time, a power of 400 W to 1000 W may be supplied. In this manner, the number of stages by which the RF power is increased may be changed as appropriate.

[0048] As in the present invention, by gradually increasing the RF power supplied to the upper coil 130, the plasma density gradually changes from a low density state to a high density state, thereby minimizing damage to the inner wall of the chamber 100 and suppressing the generation of particles.

[0049] Meanwhile, when increasing the RF power step by step, it is preferable to maintain a constant difference in the RF power between each step. For example, the upper coil 130 may be initially supplied with a power of 100 W to 300 W, then with a power of 400 W to 600 W, and finally with a power of 700 W to 900 W. In this case, the intensity of the plasma inside the processing space 110 can be increased in the same manner, thereby reducing particles that may be generated on the inner wall of the chamber 100.

[0050] Then, a voltage is applied to the chucking electrode 322 of the electrostatic chuck 300 to hold the substrate W, and a process gas is supplied through the gas distribution plate 150 to deposit a hard mask thin film on the upper surface of the substrate W.

[0051] In this case, RF power may be supplied to the upper coil 130 and also to the bias electrode 332 .

[0052] After the hard mask thin film is deposited on the upper surface of the substrate W, the supply of plasma inside the chamber 100 is stopped.

[0053] In this case, if the RF power supplied to the upper coil 130 is turned off all at once, there is a risk that particles and the like that have been captured by the plasma electric field and are located on the top of the substrate W will fall from the top surface of the substrate W as soon as the RF power is turned off.

[0054] Therefore, in the present invention, in the step of stopping the supply of plasma inside the chamber 100, the RF power supplied to the upper coil 130 is gradually reduced to turn off the RF power.

[0055] In this case, when the RF power is gradually reduced, the RF power can be reduced step by step.

[0056] For example, the RF power supplied to the upper coil 130 can be gradually reduced over multiple steps.

[0057] Also, the RF power can be gradually reduced, and the supply amount of inert gas such as argon gas supplied through the gas distribution plate 150 can be increased. For example, the supply amount of inert gas can be approximately two to three times the amount of inert gas supplied during the process on the substrate W.

[0058] In this way, by increasing the supply of argon gas, the exhaust pump 182 can more effectively exhaust foreign matter such as particles from inside the chamber 100, thereby reducing the adhesion of particles and the like to the substrate W.

[0059] The RF power supplied to the bias electrode 332 may be gradually reduced or may be turned off immediately.

[0060] Meanwhile, when a hard mask thin film is deposited on the upper surface of the substrate W and the RF power supplied to the upper coil 130 is stopped, the supply of RF power to the first coil 130A disposed in the center of the chamber 100 may be stopped first, and after a predetermined time has elapsed, the supply of RF power to the second coil 130B may be stopped.

[0061] In this case, if the supply of RF power to the first coil 130A is stopped first, the plasma will disappear below the first coil 130A, and the plasma will remain below the second coil 130B located at the outer periphery. Furthermore, as the plasma region moves toward the outer periphery of the processing space 110, particles and the like will move toward the outer periphery or edge of the processing space 110.

[0062] In this state, if the supply amount of inert gas such as argon gas supplied through the gas distribution plate 150 is increased, foreign matter such as particles inside the chamber 100 can be more effectively exhausted, thereby reducing the adhesion of particles and the like to the substrate W.

[0063] The supply of RF power to the first coil 130A may be discontinued, and after a predetermined time, the supply of RF power to the second coil 130B may be discontinued.

[0064] Next, the voltage supply to the chucking electrode 322 of the electrostatic chuck 300 is stopped, the substrate W is dechucked, and the substrate W is transferred to the outside of the chamber 100 .

[0065] In this case, there is a risk that the opening (not shown) of the chamber 100 will open, causing a sudden change in the pressure inside the chamber 100, which may lead to the scattering of particles and the like inside the chamber 100.

[0066] Therefore, in order to prevent such particle scattering, the supply amount of inert gas, such as argon gas, supplied through the gas distribution plate 150 can be adjusted to maintain a constant pressure inside the chamber 100 when the substrate W is moved.

[0067] That is, the flow rate of the argon gas can minimize the change in pressure inside the chamber 100, thereby suppressing the scattering of particles that may occur due to a sudden change in pressure inside the chamber 100.

[0068] Meanwhile, after depositing a hard mask thin film made of an amorphous carbon film on the substrate W through the above steps, a step of cleaning the inside of the chamber 100 may be performed. This cleaning step may be performed by depositing a hard mask thin film on the substrate W once, or by performing the deposition process multiple times. For example, the deposition process may be performed four times and the cleaning process may be performed once, and these numbers of times may be adjusted as appropriate.

[0069] The amorphous carbon thin film inside the chamber 100 is cleaned by an ashing process using oxygen (O2) plasma. By cleaning the amorphous carbon thin film by the reaction of hydrogen with oxygen, particles that have peeled off from the inner wall of the chamber 100 and water (H2O) absorbed into the inner wall of the chamber 100 can be removed.

[0070] In this case, the step of supplying RF power to the upper coil 130 and the bias electrode 332 while supplying oxygen into the chamber 100 and the step of supplying RF power only to the upper coil 130 may be repeated several times.

[0071] That is, RF power may be supplied to both the upper coil 130 and the bias electrode 332 to clean the lower part of the interior of the chamber 100, and then RF power may be supplied only to the upper coil 130 to clean the upper part of the interior of the chamber 100. By repeating these steps, the interior of the chamber 100 can be effectively cleaned.

[0072] Meanwhile, in the step of cleaning the inside of the chamber 100, a step of supplying hydrogen into the inside of the chamber 100 to generate plasma may be performed.

[0073] That is, after the step of cleaning the interior of the chamber 100 is completed, hydrogen plasma may be generated by supplying hydrogen gas into the interior of the chamber 100 and supplying RF power to the upper coil 130 or the upper coil 130 and the bias electrode 332. By performing post-treatment using hydrogen plasma in this manner, residual impurities adhering to the inner wall of the chamber 100 can be removed, thereby reducing particles.

[0074] Meanwhile, after the step of cleaning the inside of the chamber 100, the step of purging the inside of the chamber 100 may be performed.

[0075] In this case, in order to effectively exhaust remaining gases and residues inside the chamber 100, a purge gas such as helium (He) gas may be repeatedly supplied and stopped to the inside of the chamber 100. This allows for a so-called "cyclic purge" in which the pressure inside the chamber 100 fluctuates rapidly. Meanwhile, the exhaust pump 182 may include the purge step and be continuously driven during the purge step.

[0076] Meanwhile, the substrate processing apparatus 1000 may further include a remote plasma source (RPS) (not shown) for providing remote plasma into the chamber 100, thereby providing remote plasma into the chamber 100.

[0077] That is, the step of depositing a hard mask thin film on the substrate W may be repeated multiple times, and the step of cleaning the chamber 100 may also be repeated multiple times, followed by the step of providing the remote plasma. For example, the step of depositing a hard mask thin film on the substrate W may be repeated approximately 40 times, and the step of cleaning the chamber 100 may be repeated approximately 10 times, followed by the step of providing the remote plasma.

[0078] Meanwhile, the remote plasma source (RPS) is connected to the side or bottom of the chamber 100 to supply remote plasma into the chamber 100, thereby efficiently cleaning the lower space inside the chamber 100.

[0079] On the other hand, Figures 3 to 5 are graphs comparing the number of particles adsorbed to a substrate when a process is performed using the substrate processing method of the present invention described above with the number of particles adsorbed to a substrate when a process is performed using a substrate processing method according to conventional technology.

[0080] First, Figure 3 (A) is a graph comparing the number of particles adsorbed on the substrate when RF power is supplied to the upper coil 130 during the step of supplying plasma into the chamber 100 and then the RF power is gradually increased to proceed with the process (Example 1), and when a conventional substrate processing method (Comparative Example) is applied that does not include such a step of gradually increasing the RF power.

[0081] Referring to FIG. 3(A), it can be seen that when the process is carried out according to Example 1, the particles are reduced by approximately 20% to 33% compared to the comparative example.

[0082] Also, (B) of Figure 3 is a graph comparing the number of particles adsorbed to the substrate when the process of gradually reducing the RF power supplied to the upper coil 130 and turning off the RF power during the step of interrupting the supply of plasma inside the chamber 100 (Example 2) is carried out, and when a substrate processing method according to conventional technology (Comparative Example) is applied that does not include such a step of gradually reducing the RF power is applied.

[0083] Referring to FIG. 3(B), it can be seen that when the process is carried out according to Example 2, the number of particles is reduced by approximately 38% to 55% compared to the comparative example.

[0084] On the other hand, (A) of Figure 4 is a graph comparing the number of particles adsorbed to the substrate when a process including a step of reducing the pressure change inside the chamber 100 using argon gas is carried out when the substrate W is transported from the inside of the chamber 100 to the outside (Example 3) and when a substrate processing method using conventional technology that does not include a step of reducing such pressure change is applied (Comparative Example).

[0085] Referring to FIG. 4(A), it can be seen that when the process is carried out according to Example 3, particles are reduced by approximately 20% to 28% compared to the comparative example.

[0086] FIG. 4B is a graph comparing the number of particles adsorbed on the substrate when a process including the aforementioned hydrogen plasma treatment step (Example 4) is carried out and when a substrate treatment method using conventional technology that does not include such a hydrogen plasma treatment step (Comparative Example) is applied.

[0087] Referring to FIG. 4(B), it can be seen that when the process is carried out according to Example 4, particles are reduced by approximately 22% to 34% compared to the comparative example.

[0088] On the other hand, FIG. 5 is a graph comparing the number of particles adsorbed onto a substrate when a process including both of the steps shown in FIGS. 3 and 4 (Example 5) is carried out, and when a substrate processing method according to conventional technology not including both of the steps shown in FIGS. 3 and 4 (Comparative Example) is applied.

[0089] Referring to FIG. 5, it can be seen that when the process is carried out according to Example 5, the number of particles is significantly reduced by about 6% to 11% compared to the comparative example.

[0090] 6 illustrates a substrate processing method according to another embodiment. Specifically, this may correspond to a method of adjusting the voltage applied to the bias electrode 332 during the step of depositing a hard mask thin film on the upper surface of the substrate W (S230) or during an etching process such as a photo process that follows the hard mask thin film.

[0091] FIG. 6 is a graph showing the application of a voltage to the bias electrode 332 by the bias power supply 334 according to the prior art.

[0092] As shown in FIG. 6A, in the case of the conventional technology, the bias power supply 334 can apply a voltage having a waveform of a so-called “sine wave” to the bias electrode 332 .

[0093] In this case, as shown in FIG. 6B, when the ion energy distribution function (IEDF) of ions due to the plasma inside the chamber 100 is examined, it appears as a shape having two peaks, such as a bimodal shape or a twin peak shape.

[0094] When the ion energy distribution function (IEDF) of ions (Ions) appears as a bimodal or twin-peak shape, the ion energy is dispersed over a wide range. In this case, the ion energy contributing to the deposition of a thin film is concentrated in a specific band, and only a portion of the ion energy contributes to the film formation. The remaining energy may increase the temperature of the substrate and increase the stress in the thin film. Furthermore, the sp2 bond composition of carbon in the amorphous carbon film may increase, degrading the quality of the thin film.

[0095] FIG. 7 is a graph showing a case where a voltage is applied to the bias electrode 332 by the bias power supply 334 according to this embodiment.

[0096] As shown in Figure 7A, the bias power supply 334 can apply a voltage with a predetermined waveform, which will be described in more detail with reference to Figure 8.

[0097] When a waveform corresponding to (A) of Figure 7 is applied to the bias electrode 332, the ion energy distribution function (IEDF) of ions (Ion) generated by the plasma inside the chamber 100 changes from a bimodal or twin-peak shape to a single-peak shape. (B) of Figure 7 shows the single-peak distribution according to this embodiment as well as the bimodal shape according to the conventional technology.

[0098] When the ion energy distribution function (IEDF) of ions appears as a single peak, the ion energy can be concentrated in a narrow range. In this case, most of the ion energy contributes to the deposition of the thin film, which minimizes the increase in substrate temperature, as was the case in the past. In addition, the increase in stress in the thin film can be minimized, and the sp3 bond composition of carbon in the amorphous carbon film can be increased, improving the quality of the thin film.

[0099] 8 is a graph showing in more detail the waveform of the voltage applied from the bias power supply 334 shown in FIG. 7. FIG. 8(A) is a graph showing the waveform of the voltage (V output ) and (B) of FIG. 8 is a graph (V sheath ) (C) and (D) of Figure 8 show the electrons or positive ions occupying the substrate W in the waveform. On the other hand, Figure 9 shows the ion energy distribution function (IEDF) of ions (Ion) due to the plasma inside the chamber 100 when the voltage waveform shown in Figure 8 is applied.

[0100] As shown in Figure 8A, the waveform may include a first section (circled number 1) having a predetermined positive value (V1), and a second section (circled number 2) having a predetermined slope (Slope) that switches to a predetermined negative value at the end of the first section (circled number 1). At the end of the second section (circled number 2), the voltage may switch to the predetermined positive value, and the first section (circled number 1) and the second section (circled number 2) may be repeated.

[0101] Also, as shown in FIG. 8A, as the waveform changes, the voltage on the substrate W can also change.

[0102] For example, as shown in Figure 8 (B), in the first section (number 1 in circle), the voltage of the substrate W may have a constant positive value. Also, in the second section (number 2 in circle), the voltage of the substrate W may have a negative value. Also, when adjusting the gradient of the slope in the second section (number 2 in circle), the voltage of the substrate W may maintain a substantially constant negative value.

[0103] On the other hand, in the first section (circled number 1), as shown in Fig. 8(C), electrons are attracted to and occupied by the substrate W. Then, in the second section (circled number 2), as shown in Fig. 8(D), cations are attracted to and occupied by the substrate W.

[0104] Meanwhile, in the first section (circled number 1), the predetermined positive value (V1) can be adjusted to shift the ion energy distribution function (IEDF) of the ions shown in (A) of Figure 9. For example, if the predetermined positive value (V1) is increased along the arrow in the first section (circled number 1), the ion energy distribution function (IEDF) of the ions can shift to the right and exhibit higher energy, as shown in (A) of Figure 9.

[0105] On the other hand, when the gradient of the slope is changed in the second section (circled number 2), the negative value of the voltage on the substrate W can be changed as shown in FIG. 8(B).

[0106] Furthermore, in the second section (circled number 2), when the gradient value (dV / dt) of the slope is increased in the direction of the arrow as shown in FIG. 8A, the upper end of the ion energy distribution function (IEDF) of the ions has a more pointed (sharp) shape as shown in FIG. 9B, thereby adjusting the degree of energy concentration.

[0107] Furthermore, if the gradient of the slope is made larger or smaller, or if the gradient of the slope is changed to have a positive value, the negative value of the voltage of the substrate W can be changed, and the voltage of the substrate W can also be changed to a value having a constant gradient rather than a constant negative value.

[0108] On the other hand, FIG. 10 is a graph showing various properties of the amorphous carbon film when the amorphous carbon film is deposited according to the embodiment shown in FIG.

[0109] FIG. 10(A) shows the G peak position and I(D) / I(G) value of the amorphous carbon film, FIG. 10(B) shows the H content (at%) and full width at half maximum (FWHM) (G) of the amorphous carbon film, and FIG. 10(C) shows the density (g / cm) of the amorphous carbon film. 3 10, the horizontal axis represents the value of the voltage applied from the bias power supply source 334.

[0110] As shown in FIG. 10, as the voltage increases, the density (g / cm) of the amorphous carbon film 3) and RI value increase. It is also found that the G peak position and I(D) / I(G) value of the amorphous carbon film increase. Furthermore, it is also found that the FWHM(G) of the amorphous carbon film increases, while the H content (at%) decreases.

[0111] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will be able to implement the present invention with various modifications and changes without departing from the spirit and scope of the present invention as defined in the claims below. Therefore, as long as the modified embodiments basically include the elements of the claims of the present invention, they should all be considered to be included in the technical scope of the present invention. [Explanation of symbols]

[0112] 100: Chamber 110: Processing space 130: Upper coil 130A: First coil 130B: Second coil 140: Window 150: Gas supply plate 160: Process gas supply source 190: Cooling gas source 300: Electrostatic chuck 310: Upper plate 312: Groove 314: Gas flow path 322: Chuck electrode 332: Bias electrode 340: Heating plate 360: Support plate 1000: Substrate processing equipment

Claims

1. A substrate processing method for a substrate processing apparatus including a chamber, an upper coil disposed in an upper portion of the chamber to generate plasma inside the chamber, and an electrostatic chuck disposed inside the chamber, comprising: providing a plasma inside the chamber; depositing a hard mask thin film on an upper surface of the substrate; Including, In the step of depositing the hard mask thin film, a voltage having a predetermined waveform is applied to a bias electrode provided in the electrostatic chuck; a second section configured to switch to a predetermined negative value at an end of the first section and have a slope with a predetermined gradient, and wherein the waveform switches to the predetermined positive value at an end of the second section, and the first section and the second section are repeated.

2. 2. The substrate processing method of claim 1, wherein an ion energy distribution function (IEDF) of ions inside the chamber has a single peak when a voltage having the waveform is applied to the bias electrode.

3. 2. The method of claim 1, wherein the positive value of the voltage applied from the first section is adjusted to shift an ion energy distribution function (IEDF) of ions inside the chamber.

4. 2. The method of claim 1, further comprising adjusting a gradient of the slope in the second section to adjust a concentration of an ion energy distribution function (IEDF) of ions inside the chamber.

5. 2. The substrate processing method according to claim 1, wherein the substrate has a predetermined positive voltage value in the first interval, and the substrate has a predetermined negative voltage value in the second interval.

6. 2. The substrate processing method according to claim 1, further comprising adjusting a gradient of the slope in the second section to adjust a negative voltage value of the substrate.

7. 2. The substrate processing method of claim 1, wherein the gradient of the slope is adjusted in the second section so that the substrate has a constant negative voltage value.

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