JP2018076559A - Sputtering device and film production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve estimation accuracy of a film deposition speed.SOLUTION: Reactive gas and inactive gas are supplied inside a chamber in which a deposition object and a target are arranged, and power is supplied to the target by a power source to generate a plasma inside the chamber. Ions of the inactive gas in the plasma are made to collide with the target, so as to form a film on the deposition object. A CPU 251 finds an estimated deposition speed corresponding to an intensity I of light received by a light receiving part 160 using corresponding data D1 in which the light intensity is made to correspond to the deposition speed, and controls at least one of a flow rate of the reactive gas, a flow rate of the inactive gas and an output of the power source so that the estimated deposition speed R approaches to a target deposition speed R. The light intensity and the deposition speed in the corresponding data D1 has a relationship different from a proportional relationship.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sputtering apparatus for forming a film on an object to be formed by reactive sputtering, and a method for manufacturing the film.

  Sputtering is utilized for the purpose of forming a film on various film forming objects such as an optical thin film and a semiconductor integrated circuit. Sputtering for forming a thin film of a compound on an object to be formed includes high-frequency sputtering in which a compound target is sputtered by high-frequency discharge and reactive sputtering in which a reactive gas is introduced into a chamber to sputter a metal target. . In recent years, reactive sputtering has been used in order to reduce costs and improve productivity.

  In reactive sputtering, for example, as disclosed in Non-Patent Document 1, it is known that there are three states with different film formation rates and film qualities. The three states are called a metal mode, a transition mode, and a compound mode. The compound mode is also called the reactive mode. As the reactive gas reacts with atoms on the target surface, the surface of the target is coated with the compound. In the compound mode, compounding of the target surface is sufficient, but the film formation rate is slow. In the metal mode, compounding of the target surface is insufficient, but the film formation rate is fast. In the transition mode, compound and metal are mixed on the surface of the target, and the deposition rate is faster than that in the compound mode. However, the deposition rate fluctuates greatly only by slightly changing the process conditions such as the flow rate of the reactive gas. It is an unstable state.

  As a film formation control method in the transition mode, plasma emission monitor control, that is, PEM control is known. PEM control is a method of monitoring plasma emission and performing stable film formation by feedback control such as PID control.

  In Patent Document 1, as a method for accurately forming a film having a desired film thickness, when the light intensity, that is, the film formation speed is stabilized at a constant value by PEM control, the film is partitioned by a partition wall. There has been proposed a method of starting film formation by moving an object to be formed into the film formation chamber.

Japanese Patent No. 4876619

S. Berg, H .; O. Blom, T .; Larsson, and C.L. Nender: J.M. Vac. Sci. Technol. A, 5, (1987), 202

  However, conventionally, since it has been necessary to wait until the film formation rate is stabilized at a constant value after the discharge is started, the productivity of the film-formed product is reduced by the waiting time. In order to shorten the waiting time, it is conceivable to start the film formation before the film formation rate is stabilized, that is, in a state where the film formation rate varies greatly. However, when the film formation rate fluctuates greatly, for example, when the mode changes from the compound mode to the transition mode, there is a problem that an error in the estimated film formation rate with respect to the actual film formation rate increases.

  Accordingly, an object of the present invention is to improve the estimation accuracy of the film formation rate.

  The sputtering apparatus of the present invention includes a chamber in which a film formation target and a target are disposed, a reactive gas supply unit that supplies a reactive gas to the inside of the chamber, and an inert gas that supplies an inert gas to the inside of the chamber. An active gas supply unit, a power source for supplying power to the target to generate plasma in the chamber, and ions of the inert gas in the plasma collide with the target, and light emitted by the plasma are received. Using the correspondence data associated with the light receiving unit and the relationship between the light intensity and the film forming speed in a relationship different from the proportional relationship, an estimated film forming speed corresponding to the light intensity received by the light receiving unit is obtained, A control unit that controls at least one of the flow rate of the reactive gas, the flow rate of the inert gas, and the output of the power source so that the estimated deposition rate approaches the target deposition rate; Characterized in that it comprises a.

  According to the present invention, even when the film formation rate fluctuates, such as when changing from the compound mode to the transition mode, the film formation rate can be estimated with high accuracy, and the discharge is started after the discharge is started. Since the waiting time until the film is started can be shortened, the productivity of the film-formed product is improved.

It is explanatory drawing which shows the sputtering device which concerns on 1st Embodiment. FIG. 3A is a block diagram illustrating a configuration of a controller in the first embodiment. (B) is a block diagram showing functions of the CPU of the controller. (A) And (b) is a figure which shows the relationship of the film-forming speed | rate with respect to the flow volume of reactive gas. It is a flowchart which shows the manufacturing method of the film | membrane in 1st Embodiment. (A) is a figure which shows the relationship between the time after discharge start, and the intensity ratio of light. (B) is a figure which shows the function used for the film-forming-rate estimation process in 1st Embodiment, and the function of a comparative example. (A) is a figure which shows the relationship between the measured value of the film thickness in 1st Embodiment, and the calculated value of a film thickness. (B) is a figure which shows the relationship between the measured value of the film thickness in a comparative example, and the calculated value of a film thickness. It is a graph which shows the experimental result of the light intensity ratio and film-forming speed | rate in 2nd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an explanatory view showing a sputtering apparatus according to the first embodiment. The sputtering apparatus 100 is a DC magnetron sputtering apparatus in the first embodiment. The sputtering apparatus 100 forms a thin film such as an antireflection film on the surface of the lens substrate W, which is a film formation target, by reactive sputtering. By forming a thin film on the surface of the lens substrate W by the sputtering apparatus 100, a final product such as a lens or an intermediate product of the lens is manufactured.

  The sputtering apparatus 100 includes a chamber that is decompressed to a vacuum, that is, a vacuum chamber 101, and a controller 200. The vacuum chamber 101 is evacuated by an evacuation mechanism 120 including a turbo molecular pump 121 and a roughing pump 122, and is held at a predetermined pressure. The ultimate pressure in the vacuum chamber 101 is measured by a Pirani vacuum gauge and an ionization vacuum gauge (not shown), and the pressure during film formation is measured by a diaphragm vacuum gauge (not shown).

  A target 141 and a lens substrate W are arranged inside the vacuum chamber 101. The target 141 is held by a backing plate 142 disposed inside the vacuum chamber 101. The target 141 is a film material such as metal, and is, for example, Si.

  The lens substrate W is held by a holder 152 disposed at a position facing the target 141. The holder 152 is driven to rotate about the rotation axis by the driving device 151. The holder 152 can hold a plurality of lens substrates W, and revolves around the rotation axis by rotating around the rotation axis.

  Connected to the vacuum chamber 101 is a reactive gas supply unit 131 having a flow rate regulator 133 for adjusting the flow rate of the reactive gas and a gas introduction line 134 for introducing the reactive gas into the vacuum chamber 101. That is, the flow rate regulator 133 and the vacuum chamber 101 are connected by the gas introduction line 134. A gas cylinder 139 that is a reactive gas supply source is connected to the flow rate regulator 133.

The flow rate adjuster 133 is a mass flow controller, and adjusts the flow rate of the reactive gas supplied to the vacuum chamber 101 through the gas introduction line 134 according to the target flow rate Q _O2 ^* of the reactive gas received from the controller 200. The gas introduction line 134 has a ring-shaped tube 135 disposed between the lens substrate W and the target 141 and in the vicinity of the target 141, and is uniform from a plurality of holes provided at equal intervals in the tube 135. Reactive gas is blown out. The reactive gas is supplied into the vacuum chamber 101 by the reactive gas supply unit 131 having such a configuration. The reactive gas is a gas for forming a compound film on the lens substrate W. When the film to be formed is an oxide film such as SiO ₂ , the reactive gas is O ₂ gas.

Further, the vacuum chamber 101 includes an inert gas supply unit that includes a flow rate regulator 136 that adjusts the flow rate of the inert gas, and a gas introduction line 137 that introduces the inert gas with the adjusted flow rate into the vacuum chamber 101. 132 is connected. That is, the flow rate regulator 136 and the vacuum chamber 101 are connected by the gas introduction line 137. Note that a gas cylinder 140 that is an inert gas supply source is connected to the flow rate regulator 136. The flow rate adjuster 136 is a mass flow controller, and adjusts the flow rate of the inert gas supplied to the vacuum chamber 101 through the gas introduction line 137 according to the target flow rate Q _Ar ^* of the inert gas received from the controller 200. The gas introduction line 137 includes a ring-shaped tube 138 disposed between the lens substrate W and the target 141 and in the vicinity of the target 141, and includes a plurality of holes provided at equal intervals in the tube 138. An inert gas is ejected uniformly. An inert gas is supplied into the vacuum chamber 101 by the inert gas supply unit 132 having such a configuration. The inert gas is a gas for generating plasma in the vacuum chamber 101, and is, for example, Ar gas.

  A power source 145 that is a sputtering power source is connected to the target 141, that is, the backing plate 142. The power source 145 is a direct current pulse power source, and the target 141, that is, the backing plate 142 is used as a cathode, and the vacuum chamber 101 is used as an anode. Therefore, plasma is generated in the vicinity of the target 141 by applying a negative voltage to the target 141.

  In order to suppress the temperature rise of the target 141, a cooling system 143 that cools the target 141 with cooling water is disposed in the vicinity of the back surface of the backing plate 142. A magnet 144 is installed in the vicinity of the target 141, that is, the back surface of the backing plate 142, and can generate low-voltage, high-density plasma.

  When the reactive gas is introduced into the vacuum chamber 101 by the flow controller 133, the reactive gas reacts with the atoms of the target 141 to form a compound film on the surface of the target 141. When the output power of the power source 145 is supplied to the target 141 during the introduction of the inert gas, a discharge is generated inside the vacuum chamber 101, specifically, in front of the target 141. The generated gas is ionized, that is, plasma is generated by the generated discharge. Inert gas ions in the plasma collide with the target 141 to sputter the surface of the target 141. The particles sputtered by the ions of the inert gas are emitted in front of the target 141 and form a metal oxide film on the lens substrate W.

  The sputtering apparatus 100 includes a light receiving unit 160 that receives light emitted by plasma. The light receiving unit 160 includes a collimator 161 and a spectroscope 162. The collimator 161 and the spectroscope 162 are connected by an optical fiber 163. The collimator 161 is disposed inside the vacuum chamber 101 and in the vicinity of the surface of the target 141 in a direction parallel to the surface of the target 141, and collects plasma light.

  The spectroscope 162 includes a diffraction grating and a CCD sensor, and spectrally analyzes the plasma light acquired from the collimator 161 via the optical fiber 163, and information indicating the spectral intensity of light for each predetermined wavelength, that is, the light intensity I. To the controller 200 as an electrical signal. Instead of the spectroscope 162, the light intensity I may be measured by a band pass filter (BPF) and a photomultiplier tube (PMT). The controller 200 acquires information indicating the light intensity I from the spectroscope 162 of the light receiving unit 160 as an electric signal through a signal line.

  FIG. 2A is a block diagram showing a configuration of the controller 200 in the first embodiment. The controller 200 includes a CPU (Central Processing Unit) 251 as a control unit. The controller 200 includes a ROM (Read Only Memory) 252, a RAM (Random Access Memory) 253, and an HDD (Hard Disk Drive) 254. The controller 200 also includes an interface (I / F) 255.

  A ROM 252, RAM 253, HDD 254, and interface 255 are connected to the CPU 251 via a bus. The ROM 252 stores a basic program for operating the CPU 251.

The RAM 253 is a storage device that temporarily stores various data such as the calculation processing result of the CPU 251. The HDD 254 is a storage device that stores arithmetic processing results of the CPU 251 and setting data acquired from the outside, and a program 260 for causing the CPU 251 to execute various arithmetic processing described later, that is, each step of the film manufacturing method. To record. Further, the HDD 254 stores information indicating the target film formation rate R ^* , the target flow rate Q _Ar ^* of the inert gas, and the target film thickness TH ^* .

  FIG. 2B is a block diagram illustrating functions of the CPU 251 of the controller 200. The CPU 251 operates as the estimation unit 201, the PID control unit 202, the estimation unit 203, and the determination unit 204 illustrated in FIG. 2B by operating according to the program 260 recorded in the HDD 254.

The interface 255 is connected to the light receiving unit 160, the exhaust mechanism 120, the power source 145, and the flow rate adjusters 133 and 136, and receives information indicating the light intensity I and information indicating the film forming conditions as electric signals. The information indicating the film forming conditions includes information indicating the exhaust speed by the exhaust mechanism 120, information indicating the output of the power source 145, information indicating the flow rate Q _O2 of the reactive gas by the flow rate adjuster 133, and inertness by the flow rate adjuster 136. This is information indicating the gas flow rate _QAr . The information indicating the output of the power source 145 is information indicating at least one of the output voltage, output current, and output power of the power source 145, and information indicating the output power P _W in the first embodiment. The interface 255 converts the received electrical signal into an electrical signal that can be processed by the CPU 251 as necessary.

  FIG. 3A and FIG. 3B are diagrams showing the relationship between the deposition rate and the flow rate of the reactive gas. The relationship between the flow rate of the reactive gas and the film formation rate in reactive sputtering will be described with reference to FIG. In reactive sputtering, the surface state of the target 141 includes three states with different film formation speeds and film qualities. The three states are a metal mode, a compound mode, and a transition mode between the metal mode and the compound mode. The reason why these three states exist is that the reactive gas reacts with atoms on the surface of the target 141 and the surface of the target 141 is coated with a compound.

Compound mode is a gas flow area Q _III in FIG. 3 (a) and 3 (b), a state in which a sufficient amount of the reactive gas is present to maintain the compound of the surface of the target 141. In the case of this compound mode, the reaction proceeds sufficiently and it is easy to obtain a compound that satisfies the stoichiometric ratio, but the film formation rate is slower than in the other two states. The bonding force of the compound film on the surface of the target 141 and the bonding force between the target material and the compound film are stronger than the bonding force of the target material such as metal. Since more energy is required to break these bonds and sputter the target 141 to knock out the compound, the sputtering rate of the compound is lower than the sputtering rate of the metal, and as a result, the deposition rate is slow. Become.

Metal mode is a gas flow area Q _I in FIG. 3 (a) and 3 (b), there is no sufficient amount of the reactive gas the surface of the target 141 to compounding, the target 141 The surface has a higher metal ratio than the compound. As a result, the film formation rate is higher than that in the compound mode, but the thin film to be formed is a metal that is not sufficiently reacted. Therefore, the required membrane function is often not realized.

Transition mode is a gas flow area Q _II in FIG. 3 (a) and 3 in (b), a state where the intermediate corresponding to the amount of the reactive gas with the compound mode and metal mode exists. A compound is partially formed on the surface of the target 141, and the compound and the metal are mixed. Therefore, the film formation rate is faster than the compound mode, but it is in an unstable state.

Consider a case where the flow rate of the reactive gas is decreased from the compound mode corresponding to point A in FIG. Up to point B, the surface of the target 141 is coated with a compound. In the gas flow area Q _II, also a compound of the surface of the target 141 is sputtered metallic surfaces appeared, the metal surface is coated again compound reacts immediately reactive gases. If the reactive gas flow rate is further decreased from the point B, the amount of reactive gas necessary for compounding the metal surface appearing on the surface of the target 141 becomes insufficient. Then, not only compound sputtering but also metal sputtering starts from the metal surface. Metal particles generated by metal sputtering react with part of the introduced reactive gas. Therefore, the reactive gas used for the reaction of the metal surface of the target 141 is further insufficient. As a result, the ratio of the metal mode on the surface of the target 141 rapidly increases, and the point B shifts from the compound mode B point to the metal mode D point as shown by the broken line. Similarly, when the flow rate of the reactive gas is increased from the metal mode, an abrupt change of state occurs, and a transition is made from the point C in the metal mode to the point A in the compound mode along the broken line. As a result, as shown in FIG. 3A, in the reactive sputtering, the relationship between the flow rate of the reactive gas and the film formation rate becomes a hysteresis curve. Depending on conditions, a hysteresis curve may not be obtained as shown in FIG.

  In the first embodiment, film formation is performed by plasma emission monitor control, that is, PEM control, in the transition mode in which the film formation rate is higher than that of the compound mode. Hereinafter, the PEM control by the controller 200, that is, the CPU 251 will be specifically described. FIG. 4 is a flowchart showing a film manufacturing method by PEM control in the first embodiment.

The CPU 251 outputs the command values Q _O2 ^* and Q _Ar ^* to the flow rate regulators 133 and 136 to control the flow rate of the inert gas and the reactive gas, and outputs the command value P _W ^* to the power source 145. Then, the power supplied to the target 141 is controlled to start discharging (S1).

  The CPU 251 periodically acquires information indicating the spectral intensity of the plasma light, that is, information indicating the light intensity I from the light receiving unit 160 (S2). That is, the CPU 251 measures the light intensity I at a predetermined cycle. The predetermined cycle is, for example, a cycle of 50 [msec].

  As shown in FIG. 2A, the HDD 254 stores mathematical expressions as correspondence data D1 in which light intensity and film formation speed are associated with each other. The correspondence data D1, which is a mathematical expression, is created in advance through experiments and simulations. The CPU 251 functions as the estimation unit 201 illustrated in FIG. 2B, and uses the correspondence data D1 stored in the HDD 254 to obtain an estimated film formation rate R corresponding to the intensity I of light received by the light receiving unit 160. Obtain (S3). That is, the CPU 251 estimates the film formation speed R.

In the first embodiment, the light intensity in the correspondence data D1 is the light intensity ratio I _Si / I _Ar (= the light intensity I _Si emitted from the material of the target 141 and the light intensity I _Ar emitted from the inert gas). Ip). The CPU 251 calculates a light intensity ratio I _Si / I _Ar between the light intensity I _Si emitted from the material of the target 141 and the light intensity I _Ar emitted from the inert gas from the light intensity I received by the light receiving unit 160. The film formation speed R is estimated using the correspondence data D1.

Next, the CPU 251 functions as the PID control unit 202 shown in FIG. 2B, and calculates the feedback amount so that the estimated film formation speed R approaches the target film formation speed R ^* stored in the HDD 254 in advance. And converted into a control signal. In the first embodiment, the feedback amounts are the target flow rate Q _O2 ^* and the target output power P _W ^* . The CPU 251 transmits a control signal indicating the target flow rate Q _O2 ^* to the flow rate regulator 133 to control the flow rate of the reactive gas, and transmits a control signal indicating the target output power P _W ^* to the power source 145 to The output is controlled (S4). The algorithm of feedback control in the CPU 251 is proportional-integral-derivative (PID) control. Thus, CPU 251, a film formation rate was R estimation approaches the target deposition rate R ^*, i.e. so that the difference between the deposition rate R and the target deposition rate R ^* estimate is reduced, the inert gas The flow rate and the output of the power source 145 are controlled. In the first embodiment, the CPU 251 controls the output power of the power source 145 as the output of the power source 145. Note that PID control is preferably performed as feedback control, but P control or PI control may be performed.

  The CPU 251 functions as the estimation unit 203 shown in FIG. 2B, and obtains the estimated film thickness TH from the estimated film formation speed R in step S3 (S5). That is, the CPU 251 estimates the film thickness TH. The film thickness estimation method will be described in detail. In step S3, the product of the estimated film formation rate R and the predetermined period, that is, the time interval for acquiring the light intensity I is calculated, and the calculation results are integrated. Thus, the film thickness TH is obtained. In other words, the CPU 201 obtains the film thickness TH by time-integrating the estimated film formation rate R from the time when discharge is started.

The CPU 251 functions as the determination unit 204, compares the estimated film thickness TH calculated in step S5 with the target film thickness TH ^* stored in the HDD 254 (S6), and as a result of the comparison, the estimated film thickness TH is If it is less than the target film thickness TH ^* (S6: No), the process returns to step S2. If the estimated film thickness TH is equal to or greater than the target film thickness TH ^* (S6: Yes), the CPU 251 transmits a command value to the flow rate regulators 133, 136 and the power source 145, stops discharging, and ends the film formation. . As described above, the CPU 251 performs film formation until the estimated film thickness TH reaches the target film thickness TH ^* .

FIG. 5A is a diagram showing the relationship between the time after the start of discharge and the light intensity ratio I _Si / I _Ar . Immediately after the start of discharge, the film formation rate, that is, the light intensity ratio I _Si / I _Ar is low, and the compound mode shown in FIG. 3A or FIG. When the flow rate of the reactive gas is decreased from this state, the compound mode is shifted to the transition mode, and the film formation rate, that is, the light intensity ratio I _Si / I _Ar is increased as shown in FIG. I will do it. The film formation speed, that is, the light intensity ratio I _Si / I _Ar approaches the target film formation speed R ^* in the transition mode, and stabilizes to a constant value after the time T1.

  FIG. 5B is a diagram illustrating a function used for the film forming speed estimation process in the first embodiment and a function of a comparative example. In the first embodiment, film formation is started before time T1 at which the film formation speed, that is, the intensity ratio of light is stabilized. Here, when film formation is started after time T1, the relationship between the light intensity and the film formation speed in the corresponding data is regarded as linear, that is, as a proportional relationship as shown by the broken line in FIG. However, the error of the estimated film formation rate with respect to the actual film formation rate is small. However, in the case where film formation is started before time T1, an error in the estimated film formation rate with respect to the actual film formation rate is large when regarded as a proportional relationship.

Therefore, in the first embodiment, since the film formation is started before the time T1 when the film formation speed fluctuates, the light intensity ratio I _Si / I _Ar and the film formation in the correspondence data D1 used for the estimation process in step S3. The speed is different from the proportional relation. Specifically, the mathematical formula as the correspondence data D1 is a non-linear type represented by a solid line in FIG. 5B, which is represented by a variable indicating the light intensity ratio I _Si / I _Ar and a variable indicating the film formation rate. It is a function.

Hereinafter, the function used for the estimation process of step S3 will be described in detail. Ip [a. u. ] Is a variable indicating the light intensity ratio I _Si / I _Ar , and rate [nm / sec] is a variable indicating the deposition rate. Further, a0, a1, a2, a3, and a4 are constants. Constants a0, a1, a2, a3, and a4 are values obtained in advance by experiments. In the first embodiment, the correspondence data D1 is a quartic function represented by a quaternary expression whose variable rate is a variable Ip, and is represented by the following expression (1). However, a4 ≠ 0.
rate = a0 + a1 × Ip + a2 × Ip 2 + a3 × Ip 3 + a4 × Ip 4 (1)

Expression (1) is stored in the HDD 254. In step S3, the CPU 251 obtains the light intensity ratio I _Si / I _Ar from the measurement result in step S2, substitutes I _Si / I _Ar for Ip in the formula (1) read from the HDD 254, and estimates the film formation speed. Ask for. Then, the CPU 251 obtains the estimated film thickness TH from the estimated film formation speed R in step S5, and ends the film formation when the estimated film thickness TH reaches the target film thickness TH ^* in step S6.

  Hereinafter, a method for obtaining the nonlinear function of the first embodiment and the linear function of the comparative example, which are used for the estimation of the film forming speed in step S3, will be described with reference to actual examples. The function of the first embodiment and the function of the comparative example can be obtained by experiments.

  The film thickness of the film formed by the experiment is determined using an evaluation apparatus. The evaluation apparatus uses a spectrophotometer U-4150 manufactured by Hitachi High-Technologies Corporation to measure the reflectance at an incident angle of 5 degrees and a wavelength range of 250 to 800 [nm], and use the calculation software to measure the reflectance. Fitting is calculated from the result. As calculation software, for example, it is possible to calculate using software commercially available from each company in addition to Film Wizard of Scientific Computing International. The film formation rate is calculated from the film thickness obtained by the above calculation and the actual time required for film formation.

The sputtering apparatus 100 used for the experiment was under the following conditions.
Volume of vacuum chamber 101: width 600 mm × depth 600 mm × height 800 mm
Exhaust mechanism 120: turbo molecular pump 200 L / sec, rotary pump Power supply 145: DC pulse power supply Target 141 shape: diameter φ8 inch × thickness 5 mm
Target 141 material: Si
Inert gas: Ar
Reactive gas: O ₂
Ultimate pressure: 1 × 10 ⁻⁴ Pa
Lens substrate W: synthetic quartz φ30 × 1mm thickness

  The lens substrate W was placed on the holder 152, and the distance between the surface of the lens substrate W and the surface of the target 141 was fixed at a position of about 50 [mm], and film formation was performed. Table 1 shows film formation conditions and film thickness measurement results of the first embodiment in which film formation was actually performed.

  The inert gas Ar was set to a common condition at a flow rate of 20 [sccm]. The condition of the power source 145 was a common condition for constant power of power 510 [W] and DC pulse output. During the film formation, the intensity I of the plasma light was monitored by the light receiving unit 160.

Details of the light receiving unit 160 will be described. The spectroscope 162 spectrally decomposes the plasma light via the collimator 161, and the spectral intensity I of the light is acquired. The spectrometer 162 has a wavelength range of 200 to 850 [nm] and a wavelength resolution of 1.0 [nm]. From the light spectral intensity I, the intensity ratio I _Si / I _Ar between the light intensity I _Si that is the emission line of the material Si of the target 141 and the light intensity I _Ar that is the emission line of the inert gas _Ar was calculated.

  In Table 1, condition 1 is a film forming condition in the compound mode, and all conditions except the condition 1 are conditions in which the film formation is started by starting from the compound mode and continuously changing the film forming speed up to the transition mode. It is. The film thickness was measured and calculated using the evaluation apparatus described above.

  Using the above experimental results, the constants a0, a1, a2, a3, and a4 in Equation (1) can be obtained. First, assuming equation (1), the following equation (2) obtained by time-integrating equation (1) is used. However, T is the film formation time [sec], and d is the calculated value [nm] of the film thickness.

  Constants a0, a1, a2, a3, and a4 are obtained so that the residual thickness between the film thickness d calculated using Equation (2) and the measured film thickness is minimized.

  A method for obtaining a linear function will be described as a comparative example. The film formation rate rate [nm / sec] is expressed by the following formula (3).

              rate = a × Ip (3)

  However, a is a constant. When the equation (3) is time-averaged over the entire film formation time, the following equation (4) is obtained.

  Using equation (4), the value of the constant a can be obtained from the film formation result of one of the conditions in Table 1.

  FIG. 6A is a diagram showing the relationship between the measured value of the film thickness and the calculated value of the film thickness in the first embodiment. FIG. 6B is a diagram showing the relationship between the measured thickness value and the calculated thickness value in the comparative example. In the comparative example, the constant “a” was obtained from the film formation result under the condition 3, and the calculated values of the film thickness under all conditions were obtained using the following formula (5).

  As a result of comparison between FIG. 6A and FIG. 6B, compared to the case where the film formation rate is calculated by the expression (3) of the comparative example, the compound mode is obtained by using the expression (1) according to the first embodiment. The film thickness can be calculated with high accuracy under all conditions including

  As described above, according to the first embodiment, even when the film formation speed fluctuates, such as when changing from the compound mode to the transition mode, even at the time 0 or more and less than the time T1 shown in FIG. The film formation rate R can be estimated. Further, the film thickness TH can be estimated with high accuracy by the integration process. Therefore, the film formation can be started at a timing from time 0 to less than time T1, and the waiting time from the start of discharge to the start of film formation can be shortened. improves.

  In addition, if the film formation is started at time 0, that is, when the discharge is started, the standby time can be shortened to 0, so that the productivity of the film formation product is further improved. In addition, by starting film formation at the start of discharge, it is not necessary to separately provide a shutter and a driving mechanism for driving the shutter in the vacuum chamber 101, thereby reducing costs.

  In the first embodiment, the light intensity in the correspondence data D1 is a light intensity ratio between the light intensity emitted from the material Si of the target 141 and the light intensity emitted from the inert gas Ar. In this case, the correlation between the light intensity ratio and the film formation rate is stable, i.e., the change in the film formation rate with respect to the change in the light intensity ratio is stable without being steep, and it is achieved with higher accuracy. The film speed R can be estimated.

  In the first embodiment, the function used for estimating the film deposition rate R is a quartic function in which the variable rate is expressed by a quartic expression of the variable Ip. The higher the order, the higher the accuracy of the estimated film formation rate R, but the number of film formations necessary for obtaining the function increases. Even in the fifth or higher order formula, the accuracy of the deposition rate R is almost the same as that in the fourth order formula. For this reason, the function used for estimating the deposition rate R is a quartic function, so that the number of depositions required to obtain the function is suppressed, and the deposition rate R can be estimated with high accuracy.

[Second Embodiment]
In the first embodiment, the case where the function used for the estimation of the deposition rate R is a quartic function has been described. In order to suppress the calculation load to the level of the comparative example and estimate the deposition rate R with higher accuracy than the comparative example, the function in the correspondence data D1 is expressed by the equation (6) represented by a linear expression whose variable rate is the variable Ip. It is preferable to use a linear function of However, in Expression (6), b0 and b1 are constants, and b0 ≠ 0 and b1 ≠ 0. That is, the constant b0 that is an intercept is not zero.
rate = b0 + b1 × Ip (6)

Also in this case, the constants b0 and b1 may be obtained by experiments. FIG. 7 is a graph showing experimental results of the light intensity ratio I _Si / I _Ar and the film formation rate in the second embodiment. The broken line is a linear function of Equation (6), and the constant b0 may be obtained from the intercept of the broken line, and the constant b1 may be obtained from the slope of the broken line. From the result of FIG. 7, the constant b0 is obtained as a positive value. In FIG. 7, the light intensity ratio and the film formation rate at each point correspond to the experimental values under each condition in Table 1. As described above, the function used for estimating the deposition rate R is a linear function with a constant b0 ≠ 0, so that the deposition rate R can be estimated easily and with high accuracy.

  The present invention is not limited to the embodiment described above, and many modifications are possible within the technical idea of the present invention. In addition, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

  In the above embodiment, the case where the function used for the estimation of the deposition rate R is a quartic function or a linear function has been described. However, the present invention is not limited to this. For example, the function is a quadratic function, a cubic function, Alternatively, it may be a fifth or higher order function. That is, it is preferable that the function indicating the correspondence data D1 is a function in which the variable rate indicating the film formation rate is expressed by a first-order or higher expression of the variable Ip indicating the speed of light. In the correspondence data D1, if the relationship between the light intensity and the film formation speed is different from the proportional relationship, the function in the correspondence data D1 is not limited to an n-order function (n is an integer of 1 or more), for example, an exponential function. Or a logarithmic function.

In the above embodiment, the intensity of the light in the correspondence data D1 is represented by the intensity ratio I _Si / I _Ar between the intensity I _{Si of the} light emitted from the material of the target 141 and the intensity I _{Ar of the} light emitted from the inert gas. Although the case has been described, the present invention is not limited to this.

For example, in the correspondence data D1, the light intensity is only the light intensity I _Si emitted from the material of the target 141, only the light intensity I _Ar emitted from the inert gas, or only the light intensity I _O2 emitted from the reactive gas. There may be. Also, a combination of two or more of these light intensities I _Si , I _Ar , and I _O2 , for example, an average value may be used. That is, the light intensity in the correspondence data D1 may be one or more of the light intensities I _Si , I _Ar , and I _O2 .

Further, the intensity ratio I _Ar / I _O2 between the light intensity I _Ar emitted by the inert gas and the light intensity I _O2 emitted by the reactive gas, the light intensity I _Si emitted by the material of the target 141, and the reactive gas are emitted. It may be an intensity ratio I _Si / I _O2 to the light intensity I _O2 . Furthermore, the intensity ratio may be a combination of light intensities I _Si , I _Ar , and I _O2 . For example, the intensity ratio I _Si / {(I _Ar + I _O2 ) / 2} may be used. That is, the light intensity in the correspondence data D1 may be a light intensity ratio including two or more of the light intensities I _Si , I _Ar , and I _O2 . Moreover, in the intensity ratio, the relationship between the denominator and the numerator described above may be reversed.

  Moreover, although the said embodiment demonstrated the case where CPU251 controlled the flow volume of a reactive gas and the output of a power supply as feedback control of a control part, it is not limited to this feedback control. For example, the control unit may control only the flow rate of the inert gas, may control only the flow rate of the reactive gas, or may control only the output of the power source. In addition, when the control unit controls the flow rate of the reactive gas and the flow rate of the inert gas, when the control unit controls the flow rate of the inert gas and the output of the power source, or the flow rate of the inert gas, the flow rate of the reactive gas, and the power source It may be a case of controlling the output. That is, the control unit may control at least one of the flow rate of the reactive gas, the flow rate of the inert gas, and the output of the power source so that the estimated film formation rate approaches the target film formation rate.

  Moreover, although the said embodiment demonstrated the case where the output power of a power supply was controlled as control of the output of a power supply, it is not limited to this. For example, when controlling the output voltage of the power supply, controlling the output current of the power supply, controlling the output voltage and output current of the power supply, controlling the output voltage and output power of the power supply, output current and output of the power supply It may be a case where power is controlled. In addition, the output voltage, output current, and output power of the power supply may be controlled. That is, at least one of the output voltage, output current, and output power may be controlled.

  Moreover, although the said embodiment demonstrated the case where Si was used as the target 141, it is not limited to Si, A various metal can be used. For example, Nb, Y, Sn, In, Zn, Ti, Th, V, Ta, Mo, W, Cu, Cr, Mn, Fe, Ni, Co, Sm, Pr, Bi, or the like can be used as a target. .

In the above embodiment has described the case of using an O ₂ gas as the reactive gas, not limited to O ₂ gas, it is possible to use various reactive gases. For example, as a reactive _gas, N _2, O 3, CO, etc. ₂ gas can be used.

  Moreover, although the said embodiment demonstrated the case where Ar gas was used as inert gas as carrier gas, it is not limited to Ar gas, Various inert gas can be used. For example, He, Ne, Kr, Xe, Rn gas, etc. can be used as the inert gas.

  Moreover, although the said embodiment demonstrated the case where a sputtering device was a DC magnetron sputtering device, it is not limited to this. For example, the present invention can be applied to various sputtering apparatuses such as a DC sputtering apparatus, an RF sputtering apparatus, and an RF magnetron sputtering apparatus.

  Moreover, although the said embodiment demonstrated the case where a memory | storage part was HDD254, it is not limited to this. The storage unit may be any storage device such as a USB memory, a memory card, or an SSD. The storage unit is not limited to a storage device built in the controller, and may be a storage device externally attached to the controller.

  In the above embodiment, the case where the correspondence data D1 is a mathematical formula has been described. However, the present invention is not limited to this, and the correspondence data D1 may be a table.

  The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program It can also be realized by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 100 ... Sputtering apparatus, 101 ... Vacuum chamber (chamber), 131 ... Reactive gas supply part, 132 ... Inert gas supply part, 141 ... Target, 145 ... Power supply, 160 ... Light receiving part, 251 ... CPU (control part), D1: Corresponding data, W: Lens substrate

Claims (13)

A chamber in which a film formation target and a target are placed;
A reactive gas supply unit for supplying a reactive gas into the chamber;
An inert gas supply unit for supplying an inert gas into the chamber;
A power source for supplying electric power to the target to generate plasma inside the chamber, and causing ions of the inert gas in the plasma to collide with the target;
A light receiving unit that receives light emitted by the plasma;
Using correspondence data in which the light intensity and the film formation speed are associated with each other in a relationship different from the proportional relation, an estimated film formation speed corresponding to the light intensity received by the light receiving unit is obtained, and the estimation is completed. And a control unit that controls at least one of the flow rate of the reactive gas, the flow rate of the inert gas, and the output of the power source so that the film speed approaches a target film formation speed. apparatus.   2. The sputtering apparatus according to claim 1, wherein the correspondence data is a function in which a variable indicating a film formation speed is expressed by a first-order or higher expression of a variable indicating a light speed. When the rate is a variable indicating the deposition rate, Ip is a variable indicating the light intensity, a0, a1, a2, a3, a4 are constants, and a4 ≠ 0,
rate = a0 + a1 × Ip + a2 × Ip 2 + a3 × Ip 3 + a4 × Ip 4
The sputtering apparatus according to claim 2, which is a quartic function represented by: The function is as follows: rate is a variable indicating the deposition rate, Ip is a variable indicating the light intensity, b0 and b1 are constants, and b0 ≠ 0 and b1 ≠ 0.
rate = b0 + b1 × Ip
The sputtering apparatus according to claim 2, wherein the sputtering function is a linear function represented by:   The intensity of light in the correspondence data is an intensity ratio between the intensity of light emitted from the target material and the intensity of light emitted from the inert gas, according to any one of claims 1 to 4. The sputtering apparatus as described.   The sputtering apparatus according to claim 1, further comprising a storage unit that stores the correspondence data.   The control unit periodically obtains the estimated film formation rate, obtains an estimated film thickness from the estimated film formation rate, and performs film formation until the estimated film thickness reaches a target film thickness. The sputtering apparatus according to any one of claims 1 to 6.   The control unit controls a flow rate of the reactive gas and an output of the power source so that the estimated film formation rate approaches the target film formation rate. The sputtering apparatus according to item. A reactive gas and an inert gas are supplied to the inside of the chamber in which the film formation target and the target are arranged, and power is supplied to the target by a power source to generate plasma in the chamber, and the plasma in the plasma A method of manufacturing a film that collides an inert gas ion with the target to form a film on the film formation target,
Using the correspondence data in which the light intensity and the film formation speed are associated with each other in a relationship different from the proportional relation, an estimated film formation speed corresponding to the light intensity received by the light receiving unit is obtained, and the estimated film formation is performed. A method for producing a film, comprising: controlling at least one of a flow rate of the reactive gas, a flow rate of the inert gas, and an output of the power source so that the speed approaches a target film formation speed.   10. The film manufacturing method according to claim 9, wherein the correspondence data is a function in which a variable indicating a film formation speed is expressed by a first-order or higher expression of a variable indicating a light speed. The correspondence data is as follows: rate is a variable indicating the film formation rate, Ip is a variable indicating the light intensity, a0, a1, a2, a3, a4 are constants, and a4 ≠ 0.
rate = a0 + a1 × Ip + a2 × Ip 2 + a3 × Ip 3 + a4 × Ip 4
The method for producing a film according to claim 10, wherein the film is a quartic function represented by: The correspondence data is as follows: rate is a variable indicating the film formation speed, Ip is a variable indicating the light intensity, b0 and b1 are constants, and b0 ≠ 0 and b1 ≠ 0.
rate = b0 + b1 × Ip
The film production method according to claim 11, wherein the film is a linear function represented by:   The intensity of light in the correspondence data is an intensity ratio between the intensity of light emitted from the target material and the intensity of light emitted from the inert gas, according to any one of claims 9 to 12. A method for producing the described film.

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