阅读说明：本技术 测定异常检测装置及测定异常检测方法 (Measurement abnormality detection device and measurement abnormality detection method ) 是由 伊藤敦 市桥素子 我妻美千留 于 2019-12-17 设计创作，主要内容包括：本发明涉及一种测定异常检测装置,其由谐振特性值获得多个样本。多个样本作为具有时间序列的样本组来处理,且各样本具有2个以上彼此不同的量纲。测定异常检测装置具备异常检测部(24),所述异常检测部(24)使用由样本具有的全部量纲而表示的检测指标空间,通过样本组和检测指标空间的逻辑运算,来对测定部取得的样本组中是否包含检测指标空间外的样本进行判断。(The present invention relates to a measurement abnormality detection device that obtains a plurality of samples from a resonance characteristic value. The plurality of samples are processed as a group of samples having a time series, and each sample has 2 or more dimensions different from each other. The measurement abnormality detection device is provided with an abnormality detection unit (24), and the abnormality detection unit (24) uses a detection index space represented by all dimensions of the sample, and determines whether or not the sample group acquired by the measurement unit contains a sample outside the detection index space by logical operation of the sample group and the detection index space.)

1. A measurement abnormality detection device, wherein,

the measurement abnormality of the film thickness is detected using the resonance characteristic value of the crystal oscillator,

a plurality of samples obtained from the resonance characteristic value are processed as samples having a time series and respectively have 2 or more dimensions different from each other,

the measurement abnormality detection device includes an abnormality detection unit that determines whether or not the sample acquired by the measurement unit is outside the detection index space by logical operation between the sample and the detection index space using a detection index space represented by the 2 or more mutually different dimensions, and detects the measurement abnormality if it is determined that the sample is outside the detection index space.

2. The assay abnormality detection apparatus according to claim 1,

the 2 or more mutually different dimensions include film thickness.

3. The assay abnormality detection apparatus according to claim 1 or 2,

the 2 or more mutually different dimensions include at least 1 of an equivalent series resistance and a series resonance frequency.

4. A method for detecting an abnormality in measurement, wherein,

the measurement abnormality of the film thickness is detected using the resonance characteristic value of the crystal oscillator,

the assay abnormality detection method includes:

obtaining the plurality of samples, wherein a plurality of samples are obtained according to the resonance characteristic value, and the plurality of samples are treated as samples having a time series, and each of the plurality of samples has 2 or more dimensions different from each other; and

using a detection index space represented by the 2 or more mutually different dimensions, it is determined whether or not the sample acquired by the measurement unit is outside the detection index space by logical operation of the sample and the detection index space, and if it is determined that the sample is outside the detection index space, the measurement abnormality is detected.

Technical Field

The present invention relates to a measurement abnormality detection device and a measurement abnormality detection method for detecting a measurement abnormality in film thickness measurement of a deposit deposited on a crystal oscillator.

Background

The apparatus for measuring the film thickness is mounted on a film forming apparatus such as a vacuum deposition apparatus. The QCM (Quartz Crystal Microbalance) method using a film thickness measuring apparatus is used to measure the film thickness of a deposit from a series resonance frequency and a Half-Width (Half Maximum) obtained by exciting a Crystal oscillator, or to detect that the Crystal oscillator has reached the product life (for example, see patent documents 1, 2, and 3, and non-patent document 1). The relationship between the series resonance frequency of the crystal oscillator and the film thickness is expressed by, for example, the following equation (1). The relationship between the half-value width at half maximum of the crystal oscillator and the film thickness is expressed by the following equation (2), for example. In addition, 1/2 of the conductance value at the series resonance frequency is half-width, and 1/2 of the full width at half-width in a function of the mountain shape having the series resonance frequency as a vertex is half-width. In the following formula (2), 1/2 for the full width at half maximum is also referred to as the half-width at half maximum Fw. The difference Δ Fw is a variation in the half-width at half maximum Fw, and corresponds to a variation in the half-width at half maximum Fw between two different film thicknesses.

The following equation (1) is used when the series resonance frequency in the crystal oscillator at the time of deposition is used as the input of the system. The formula (1) is mainly used when a relatively hard film of metal, metal oxide, or the like is deposited on a crystal oscillator.

The following equation (2) is used when the complex elastic modulus G and the loss elastic modulus G ″ are used as the input of the system. That is, the case where the series resonance frequency and the half-value frequency in the crystal oscillator at the time of deposition are used as the system input in the calculation of the complex elastic modulus G and the loss elastic modulus G ″. The series resonance frequency may be an n-fold wave such as a fundamental wave or a 3-fold wave of the fundamental wave. The formula (2) is used when a relatively soft film such as an organic film is deposited on a crystal oscillator.

Further, the difference between the structure using formula (1) and the structure using formula (2) is as follows: in the formula (1), only the series resonance frequency is used, and thus the configuration in measurement can be simplified. On the other hand, in the equation (2), since the half-value frequency is added as a variable, etc., there is a tendency that the derived input dimensional quantity increases, that is, the number of calculation steps increases, and the configuration is more complicated than the configuration in which the equation (1) is mainly used in the measurement, but improvement in the measurement accuracy can be expected. If the n-fold wave or the like described in patent document 4 is used, the improvement in measurement accuracy becomes more remarkable.

[ mathematical formula 1]

[ mathematical formula 2]

In the formula (1), ρ_fIs the density of the deposit, t_fIs the film thickness of the deposit, p_qIs the density of the crystal oscillator, t_qIs the film thickness of the crystal oscillator, Z is the acoustic impedance ratio, f_qIs the series resonant frequency in the crystal oscillator when not deposited. Density p_fDensity rho_qFilm thickness t_qAcoustic impedance ratio Z and series resonant frequency f_qCan be treated as constants in general. In formula (1), f_cIs the series resonance frequency in the crystal oscillator at the time of deposition, is generally a value that can be measured and can be used as an input value. By using the input value of the variable and the constants, the series resonance frequency f of the variable is determined_cWith a known value of (a), the film thickness t of the deposit can be calculated_fIn other words, e.g. film thickness t_fF (series resonance frequency f)_c) That can be regarded as a series resonance frequency f_cIs noted.

In the equation (2), the difference Δ Fw is defined as a half-value half-width Fw in the crystal oscillator when not deposited_qWith half-value half-width Fw in the crystal oscillator at the time of deposition_cThe difference of (a) is obtained. Half-value half-width Fw in crystal oscillator during deposition_cAre generally values that can be measured and are capable ofAs an input value. The difference Δ Fw can also be obtained using the parameters described below, as shown on the right side of equation (2). G is the complex modulus of elasticity, G 'is the modulus of elasticity, and G' is the loss modulus of elasticity. ω is the angular frequency, F₀Is the fundamental frequency, Z_qIs the crystal shear mode acoustic impedance. The complex elastic modulus G, the storage elastic modulus G', and the loss elastic modulus G ″ are obtained by measuring the series resonance frequency and the half-value frequency in the crystal oscillator during deposition by the methods described in the prior art documents, and using the measurement results as input values of the variables. The series resonance frequency can be obtained by combining the fundamental wave and an n-fold wave such as a 3-fold wave thereof. When the formula (2) is used, the series resonance frequency f is set_cAnd half value frequency as input value of variable, film thickness t of deposit_fCan be as thick as the film t_fF (series resonance frequency f)_cHalf-value frequency) as a series resonance frequency f_cAnd half-value frequency.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6078694

Patent document 2: japanese re-publication No. 2016/031138

Patent document 3: japanese patent laid-open publication No. 2019-65391

Patent document 4: japanese patent No. 5372263

Non-patent document

Non-patent document 1: sensors and actors B37 (1996)111-

Disclosure of Invention

Problems to be solved by the invention

In addition, if foreign matter is mixed in the deposit deposited on the crystal oscillator or the property state of the deposit is changed, the density ρ of the deposit in the above formulas is changed_fOr the acoustic impedance ratio Z varies and becomes different. In particular, the state where foreign matter is mixed into the deposit is a state where a part of the deposit contains particles having different densities, and it is difficult for three-dimensional local density variation in the deposit to be determined by a single parameter, that is, the density ρ_fTo indicate. However, in using the series resonance frequency and the membraneIn the film thickness measuring apparatus having a thick relation, even the density ρ of the deposit_fOr the acoustic impedance ratio Z varies as described above, and the density ρ regarded as a deposit may be set_fOr the acoustic impedance ratio Z is not changed. That is, the measured value obtained from the series resonance frequency is suitably interpreted as the density ρ of the deposit_fOr the above-mentioned relational expression having the same acoustic impedance ratio Z is output as it is when no foreign matter is mixed into the deposit. Therefore, even in a state where the crystal oscillator needs to be replaced, the density ρ of the deposit varies from that described above_fOr the measurement abnormality due to the acoustic impedance ratio Z, is not detectable by the film thickness measuring apparatus. In the present specification, the description will be given of an abnormality range including a case where the measurement abnormality cannot be detected by the conventional method, and the description will be given of an abnormality detected by the conventional method such as a product life as an individual abnormality only.

The invention aims to provide a measurement abnormality detection device and a measurement abnormality detection method which can detect measurement abnormality when measuring the film thickness of a deposit deposited on a crystal oscillator.

Means for solving the problems

The measurement abnormality detection device for solving the above-described problems is a measurement abnormality detection device for detecting a measurement abnormality of a film thickness using a resonance characteristic value of a crystal oscillator, wherein a plurality of samples obtained from the resonance characteristic value are processed as samples having a time series and each having 2 or more dimensions different from each other, and the measurement abnormality detection device includes an abnormality detection unit for determining whether or not the sample obtained by the measurement unit is outside a detection index space by logical operation between the sample and the detection index space using the detection index space represented by the 2 or more dimensions different from each other, and detecting the measurement abnormality if it is determined that the sample is outside the detection index space.

The method for detecting measurement abnormality for solving the above problem is a method for detecting measurement abnormality of film thickness using a resonance characteristic value of a crystal oscillator, and includes acquiring a plurality of samples from the resonance characteristic value. The plurality of indexes are processed as time-series samples, and each of the plurality of indexes has 2 or more dimensions different from each other. The method for detecting a measurement abnormality further includes determining whether or not the sample acquired by the measurement unit is outside the detection index space by a logical operation between the sample and the detection index space using a detection index space represented by the 2 or more mutually different dimensions, and detecting a measurement abnormality if it is determined that the sample is outside the detection index space.

According to each of the above configurations, the detection index space is two or more dimensions expressed by different dimensions, and it is determined whether or not the plurality of samples acquired by the measurement unit include a sample outside the detection index space by logical operation between the sample and the detection index space. Then, when it is determined that the sample outside the detection index space is included, it is detected that a measurement abnormality has occurred. Thus, even in a measurement environment where an abnormality cannot be determined based on only the conventional one-dimensional index, it is possible to detect the occurrence of an abnormality at the time of measurement.

The film thickness measuring apparatus may include a film thickness.

In the film thickness measuring apparatus, the 2 or more mutually different dimensions may include at least 1 of an equivalent series resistance and a series resonance frequency.

Drawings

Fig. 1 is a configuration diagram showing a configuration of a measurement abnormality detection device provided in one embodiment of a film thickness measurement device.

Fig. 2 is a circuit diagram showing an equivalent circuit of the crystal oscillator.

Fig. 3 is a graph showing the series resonance frequency and the half-value frequency in the conductance waveform.

Fig. 4 is a graph showing an example of the relationship between the frequency and the equivalent series resistance.

Fig. 5 is a graph showing another example of the relationship between the frequency and the equivalent series resistance.

Fig. 6 is a graph showing an example of the relationship between the equivalent series resistance and the film thickness.

Detailed Description

Hereinafter, an embodiment of a measurement abnormality detection device and a measurement abnormality detection method will be described with reference to fig. 1 to 6. In the present embodiment, an example will be described in which a film thickness measuring device including a measurement abnormality detecting device is mounted on a film forming device. The film thickness measuring apparatus measures the film thickness and determines the abnormality of the film thickness measurement. The film deposition apparatus performs feedback control or the like on the deposition rate of the film deposition material based on the film thickness and the determination result output from the film thickness measurement apparatus.

As shown in fig. 1, the film forming apparatus includes a vacuum chamber 11. The vacuum chamber 11 accommodates a vapor deposition source 12 and a detection device 14 therein. The vapor deposition source 12 is connected to an external power source 13. The vapor deposition source 12 receives power supply from a power source 13 and sublimates a film forming material toward a substrate, not shown. The sublimation system of the vapor deposition source 12 is, for example, a resistance heating system, an induction heating system, an electron beam heating system, or the like. The film-forming material is a metal compound material such as an organic material, a metal oxide, or a metal nitride. The substrate is a semiconductor substrate, a quartz substrate, a glass substrate, a resin film, or the like. The film forming material is deposited in the same manner in the substrate and the inspection apparatus 14.

The film thickness measuring apparatus includes a detecting device 14 and a control device 20. The control device 20 includes a control unit 21, a storage unit 22, a measurement unit 23, and an abnormality detection unit 24. The control device 20 has a function of controlling the film deposition apparatus in addition to the function of controlling the detection device 14.

The detection device 14 includes a crystal oscillator. The crystal oscillator has a predetermined series resonance frequency as a natural vibration number. The material constituting the crystal oscillator is, for example, an AT-cut crystal oscillator or an SC-cut crystal oscillator. The series resonance frequency of the crystal oscillator is, for example, 3MHz or more and 6MHz or less. The detecting device 14 is used for measuring the film thickness and the deposition rate of the deposition deposited on the substrate. The measured values and calculated values of the film thickness, the deposition rate, and the like are used in the film deposition apparatus as feedback amounts of the process performed by the film deposition apparatus. The detection device 14 is disposed in the vacuum chamber 11 so as to face the vapor deposition source 12. The detection device 14 outputs the detection result to the control device 20.

The surface of the crystal oscillator is disposed opposite to the vapor deposition source 12. On the surface of the crystal oscillator, a film-forming material is deposited from the evaporation source 12 at arbitrary time intervals. The film-forming material deposited on the surface of the crystal oscillator changes the vibration frequency of the crystal oscillator as a new additional mass at arbitrary time intervals. Further, the quality of the deposit on the surface of the crystal oscillator is related to the density of the deposit. That is, by measuring the change in the oscillation frequency of the crystal oscillator, the film thickness, that is, the length of the film forming material deposited on the surface of the crystal oscillator can be determined. Then, the film thickness measuring apparatus indirectly measures the film thickness from the vibration waveform as a result of the vibration by exciting the crystal oscillator.

The film thickness measuring apparatus uses an ac signal, which is a frequency signal, as an excitation source. The excited crystal oscillator responds as a system containing deposits adhering to the surface. The film thickness measuring apparatus detects a response of the crystal oscillator including a mechanical vibration phenomenon as an electrical vibration waveform via a piezoelectric effect of the crystal oscillator. The film thickness measuring apparatus stores a waveform as a detection result and analyzes the stored waveform. The film thickness measuring device extracts and outputs the film thickness included in the waveform analysis result.

FIG. 2 is a system showing response to excitation using an equivalent circuit. The equivalent circuit shown in fig. 2 is also referred to as a measurement system.

As shown in fig. 2, the crystal oscillator is shown as a parallel circuit in which a series resonant circuit composed of a dynamic capacitor C1, a dynamic inductor L1, and an equivalent series resistor R1 is connected in parallel to a shunt capacitor C0. The series resonant circuit is an equivalent circuit of a mechanical vibration element including a crystal oscillator. The shunt capacitance C0 is, for example, a capacitance between electrodes sandwiching the crystal oscillator, including a parasitic capacitance of a package or the like for holding the crystal oscillator. The equivalent series resistance R1 represents a loss component of vibration such as internal friction, mechanical loss, and acoustic loss when the crystal oscillator vibrates. The higher the equivalent series resistance R1, the more difficult the crystal oscillator is to vibrate.

Returning to fig. 1, the measuring unit 23 of the control device 20 includes a first measuring unit 23A and a second measuring unit 23B. However, the measurement unit 23 only needs to include at least one of the first measurement unit 23A and the second measurement unit 23B. That is, the measuring unit 23 may be configured to omit the first measuring unit 23A, or may be configured to omit the second measuring unit 23B. The control device 20 mainly controls the processes performed by the film formation device, and the control unit 21 mainly controls the processes performed by the film thickness measurement device.

The controller 20 causes the power source 13 to supply electric power and sublimates the film forming material from the vapor deposition source 12 toward the substrate. The control device 20 performs feedback control of the output power of the power supply 13 so that the deposition rate becomes a target value, for example, using the deposition rate obtained from the control unit 21. When the film formation using the vapor deposition source 12 is started, the control section 21 reads the measurement program, the measurement abnormality detection program, and the like stored in the storage section 22, and executes the read programs, thereby executing the film thickness measurement method and the measurement abnormality detection method.

The control unit 21 causes the measuring unit 23 to input an ac signal to the detection device 14. In the configuration including the first measurement unit 23A, the control unit 21 causes the first measurement unit 23A to measure the series resonance frequency Fs, for example. In the configuration including the second measuring unit 23B, the control unit 21 causes the second measuring unit 23B to measure the series resonance frequency Fs, the half-value frequencies F1 and F2, and the half-value bandwidth by scanning the frequency of the ac signal in the vicinity of the series resonance frequency Fs of the crystal oscillator.

The control unit 21 causes the storage unit 22 to store the vibration waveform to which the detection device 14 responds. The control unit 21 causes the storage unit 22 to store various values processed by the measurement unit 23 and the abnormality detection unit 24. The control unit 21 analyzes the vibration waveform, or causes the measurement unit 23 to analyze the vibration waveform. The control unit 21 causes the measuring unit 23 to calculate the film thickness at a predetermined time interval, that is, the deposition rate. Then, the control unit 21 causes the abnormality detection unit 24 to process the various values input from the measurement unit 23.

When receiving a message from the control device 20 that the film formation has been completed, the control unit 21 terminates the execution of the measurement program.

The control unit 21 is configured by hardware and software for a computer, such as a CPU (central processing unit), a RAM (random access memory), and a ROM (read only memory). The control unit is not limited to processing all of the various processes by software. For example, the control unit may include an integrated circuit (ASIC) for determination purposes as dedicated hardware for executing at least a part of various processes. The control unit may be configured to include 1 or more dedicated hardware circuits such as ASICs, 1 or more microcomputers functioning as processors in accordance with software as a computer program, or a combination of these circuits.

The storage unit 22 stores various values such as a target value, an index, a detection index space, a sample, a voltage vibration waveform, an excitation frequency range, and an excitation signal waveform, a film thickness measurement program, a measurement abnormality detection program, and data. The control unit 21 reads various values, film thickness measurement programs, and data stored in the storage unit 22, and executes the film thickness measurement programs, thereby causing the measurement unit 23 to execute various processes. The control section 21 executes various processes. The various values, measurement abnormality detection program, and data stored in the storage unit 22 are read, and the measurement abnormality detection program is executed to cause the abnormality detection unit 24 to execute various processes including determination of measurement abnormality.

The first measurement unit 23A is configured to: in cooperation with the storage unit 22 and the control unit 21, the series resonance frequency Fs of the crystal oscillator, which is an example of the resonance characteristic value, can be measured. The first measurement unit 23A includes, for example, an oscillation circuit and a measurement circuit. The oscillation circuit uses the ac signal as an excitation signal, and inputs a specific frequency, such as the series resonance frequency Fs of the crystal oscillator when deposition is not performed or a frequency in the vicinity thereof, to the crystal oscillator provided in the detection device 14, to vibrate the crystal oscillator. The measurement circuit measures a voltage oscillation waveform, which is an attenuation response after stopping the excitation, for example, and records the result in the storage unit 22. The control unit 21 calculates a required resonance characteristic value for the recorded voltage oscillation waveform by using a known analysis method prepared in advance. An example of the analysis method is a method using exponential-functional attenuation (hereinafter, also referred to as Ring-down analysis). Ring-down analysis is an analysis method using: the fluctuating mass attached to the surface of the crystal oscillator can be observed as a kinetic energy release fluctuation in the decay response.

The second measurement section 23B functions as a so-called network analyzer. The second measurement unit 23B is configured to: the series resonance frequency Fs and the half-value frequencies F1 and F2 can be measured without cooperating with the storage unit 22 and the control unit 21. The second measurement unit 23B is configured to: the oscillation signal supplied to the crystal oscillator is removed from a voltage oscillation waveform which is a response of the superposition of the oscillation signal, and only the response signal is separated. For example, the signal supply circuit inputs an ac signal as an excitation signal to a crystal oscillator provided in the detection device 14. The excitation signal is, for example, a sine wave sweep signal around the series resonance frequency Fs of the crystal oscillator. The measurement circuit obtains the series resonance frequency Fs, the half-value frequencies F1 and F2, and the half-value half width Fw from the response signal, for example. The series resonance frequency Fs, the half-value frequencies F1, F2, and the half-value half-width Fw are examples of resonance characteristic values.

In this way, when the measuring unit 23 has a configuration including the first measuring unit 23A or the second measuring unit 23B, it is possible to obtain an input value for deriving a function of the film thickness, that is, a variable in the equation (1) or the equation (2). The control unit 21 may be configured to select one of the first measurement unit 23A and the second measurement unit 23B based on the measurement result. The measurement unit 23 may be configured to calculate variables other than the variables described in expressions (1) to (6) as necessary.

As shown in fig. 3, the half-value frequencies F1, F2 are 1/2 frequencies that give the maximum value of conductance (conductance) in the series resonance frequency Fs. The half-value bandwidth is twice the half-value bandwidth Fw and is a difference value between the half-value frequency F1 on the one hand and the half-value frequency F2 on the other hand. In other words, the half-width Fw is 1/2 of the half-width.

However, the Q value and the D value, which are indexes of the accuracy and stability of the oscillation frequency in the crystal oscillator, are expressed by the following expressions (3) and (4). When the equivalent series capacitance C1 can be treated as a constant without changing, the dynamic inductance L1 is expressed by the following expression (5) using the series resonance frequency Fs, and the equivalent series resistance R1 is expressed by the following expression (6). These equations are stored in the storage unit 22. The control unit 21 calculates various values using the above equations. For example, the controller 21 performs calculations based on the above equation in time series each time the half-value frequencies F1 and F2 and the series resonance frequency Fs are obtained in the measuring unit 23. The calculation performed by the control unit 21 may be performed by the abnormality detection unit 24. The calculation values that are the results of the calculation performed in time series are stored in the storage unit 22 after the time index values are assigned in time series. The same time index value is given to the result of calculation using half-value frequencies F1 and F2 and series resonance frequency Fs obtained at the same opportunity in measurement unit 23. The time index value is given by any one of the measurement unit 23, the control unit 21, and the abnormality detection unit 24.

Fs/(2 × Fw) … formula (3)

D1/Q … type (4)

L1＝1/((2π×Fs)²X C1) … formula (5)

R1 ═ 4 pi × L1 × Fw … formula (6)

The measurement unit 23 repeatedly performs a process including measurement and analysis of the resonance characteristic value at predetermined time intervals, and transfers the measurement value and the calculated value to the storage unit 22. The time interval for measurement may be fixed to the shortest time within a range that can be handled from the viewpoint of accuracy, but may be variable including a temporary interruption of the control device 20 or the control unit 21. Since the time variation is recorded in the storage unit 22 as a relative relationship with the time index value, it can be used for the subsequent numerical processing such as the calculation processing of the deposition rate at each predetermined time.

Returning to fig. 1, the abnormality detection unit 24 is configured to: the signal used by the measurement unit 23 for measurement and analysis and the measurement value and the calculation value stored in the storage unit 22 can be used. Examples of the measured value and the calculated value stored in the storage unit 22 include voltage vibration waveforms, which are time response waveforms of excitation and response, half-value frequencies F1 and F2, a series resonance frequency Fs, a conductance value at a resonance frequency, an equivalent series resistance R1, a film thickness, and the like. The index value for specifying the detection index space is a value experimentally determined in advance for determining the presence or absence of a measurement abnormality, and is manually input to the storage unit 22 via the control device 20, for example.

The abnormality detection unit 24 is configured to process a combination of 2 or more values given the same time index value as a sample. That is, a plurality of samples become spreadsheet (Spread Sheet) -like data having time index values. In addition, when processing a sample, the measurement unit and the control unit 21 may create a sample group that is a plurality of samples, store the sample group in the storage unit 22, and then use the sample group for the abnormality detection unit 24.

The following describes an outline of detection of measurement abnormality by the abnormality detection unit 24. In the following description, the abnormality detection unit 24 includes the specification unit 25 and the detection unit 26.

First, in the preparation step, the abnormality detection unit 24 sets a detection index space based on the index value stored in the storage unit 22. The index value is a value specific to a normal range in the dimension for setting the detection index space. The detection index space is a space indicating a normal range in measurement, and is a space having a two-dimensional or more area. In the present embodiment, each dimension of the detection index space is set to correspond to each physical quantity. The dimensions and the physical quantities have a one-to-one correspondence, and the dimensions may be replaced with the corresponding physical quantities. Next, in the preparation step, the abnormality detection unit 24 selects each physical quantity so that the measurement value measured by the measurement unit 23 or the measurement value or the calculation value stored in the storage unit 22 becomes a value corresponding to the dimension of the set detection index space.

The abnormality detection unit 24 acquires a selected physical quantity value, which is a selected physical quantity, in a working process in accordance with a processing command from the control unit 21. The acquisition of the value of the selected physical quantity may be sequential processing synchronized with the processing by the measuring unit 23, or may be processing not synchronized with the processing by the measuring unit 23 when a time index value is given to the value of the selected physical quantity. In addition, the following describes the case of sequential processing. The value of the selected physical quantity acquired by the abnormality detection unit 24 is processed as a sample. The samples are indexed using the time index value. By using the index, for example, the amount of change per unit time between arbitrary samples can be calculated. In the above description, the values acquired by the abnormality detection unit 24 are examples of the selected physical quantities, but the values acquired by the abnormality detection unit 24 may be various values such as dimensionless values as will be described later.

The abnormality detection unit 24 is configured to display the samples as dots in the same space as the detection index space. In the present embodiment, the abnormality detection unit 24 is configured to display the detection index space and the sample on the same two-dimensional plane. The abnormality detection unit 24 causes the determination unit 25 to execute the above-described operation, for example. The determination section 25 specifies a point on the two-dimensional plane where the sample is displayed, and then determines whether or not the sample is outside the detection index space. For example, with respect to each coordinate value of the sample in the two-dimensional plane, it is determined whether or not the sample is within the normal range of the detection index space display by performing logical operations such as determination of the magnitude relation with each index value specifying the normal range. In the present embodiment, the specification unit 25 specifies the detection index space as a closed two-dimensional plane, and determines that the measurement is normal when the coordinates of the sample are present in the normal range, and determines that the measurement is abnormal when the coordinates of the sample are not present in the normal range.

When determining that the measurement is abnormal, the specification unit 25 inputs the detection of the occurrence of the measurement to the storage unit 22, for example. When receiving the message of the occurrence of the measurement abnormality from the storage unit 22 or the specification unit 25, the detection unit 26 performs necessary processing and then outputs a message indicating that the occurrence of the measurement abnormality is detected. When the control unit 21 or the control device 20 receives an output indicating that a measurement abnormality has occurred, for example, a work for replacing the crystal oscillator or a work for stopping the film formation apparatus is started. The necessary processing performed by the detection unit 26 is processing relating to a time region, and is signal processing representing a noise reduction method, for example. For example, a process of detecting a measurement abnormality after a plurality of abnormality determinations is performed. However, in particular, if the processing for the time domain is not necessary, the result determined by the determination unit 25 may be immediately output. In the above configuration, the detection unit 26 may be omitted.

When the abnormality detection unit 24 determines that the measurement is normal, the control unit 21 instructs execution again at a predetermined time interval, and acquires a value of the selected physical quantity to cause the abnormality detection unit 24 to perform the determination. Normally, this process is repeated until the control device 20 of the film deposition apparatus finishes the film deposition.

The value of the sample is typically a physical quantity constituting each item of the formulae (1) to (6), but each item may be a dimensionless quantity by changing the formulae (1) to (6). In this case, the dimensional value of the detection index space is set, that is, the index value stored in the storage unit 22 is also a dimensionless amount. Even in the configuration using the dimensionless quantity, the same result can be obtained by determining whether or not a sample exists in the detection index space. The number of dimensions constituting the sample may be equal to or larger than the dimensions constituting the detection index space. In the present embodiment, as shown in fig. 4 and 5, a set of the series resonance frequency fs (mhz) and the equivalent series resistance R1(Ω) and a set of the film thickness (μm) and the equivalent series resistance R1(Ω) are used as two-dimensional samples. Further, if there is a correlation between 2 physical quantities, physical quantities not present in the above-described equations (1) to (6) may be used. For example, the current flowing through the entire equivalent circuit shown in fig. 2, the current flowing through the shunt capacitor C0, and the like may be included in the dimension of the sample.

Since the plurality of samples have time index values, the abnormality detection section 24 can specify samples of a specific time range from now on, and can extract a sample group of the specified range. That is, the abnormality detection unit 24 may determine each sample, count the determination results, and calculate the occurrence rate of the most recent abnormality per hour, that is, the abnormality rate in dimensional units. This indicates that each dimension can set the abnormality detection sensitivity of the time zone. In other words, the abnormality detection unit 24 performs the following processing: an index which becomes a normal range is set for each physical quantity, an abnormality determination is performed, and further, whether or not an abnormality rate per unit time exceeds a predetermined value is repeatedly determined for each physical quantity, and then, a measurement abnormality is detected. As another similar method, for example, a numerical operation method simulating one-time lag may be substituted, and the same function can be achieved.

An example of detection of measurement abnormality using 2 dimensions will be described with reference to fig. 4. Fig. 4 and 5 show samples in which the normal case and the membranous abnormal case have been previously determined by experiments performed in advance.

The measurement of the film thickness is a time-series measurement when the film formation material is deposited on the crystal oscillator. Therefore, as the deposition of the film formation material on the crystal oscillator proceeds, the series resonance frequency Fs decreases by the added mass, and the state shifts toward the left end of the frequency axis. That is, the right end of the frequency axis in fig. 4 shows a state where the film formation material is not deposited on the crystal oscillator and the film thickness is zero. Then, the crystal oscillator when the film thickness was zero was shown to resonate in series at 5 MHz.

< first embodiment >

In the example shown in fig. 4, a first embodiment is included in which the deposit is gold. The abnormality detection unit 24 sets 5MHz or less and 4.2MHz or more as the first detection index corresponding to the series resonance frequency Fs as 1 dimension. The abnormality detection unit 24 sets a value of 20 Ω to 50 Ω as a second detection index corresponding to the equivalent series resistance R1, which is another dimension. The 2 indices are 4 sets of coordinate points, and define a detection index space in which a rectangular plane is defined. The first detection index may be 4.2MHz or more, and this configuration is suitable for a case where abnormality determination is not necessary for the upper limit of the first detection index so that a crystal oscillator or the like subjected to inspection is used.

Here, in the conventional technology as in patent document 3, for example, when the series resonance frequency Fs is lower than 4.2MHz, it is assumed that the usable period of the crystal oscillator is ended by deposition, that is, it is determined that the crystal oscillator has reached the end of its service life. That is, when the series resonance frequency Fs obtained by analyzing the vibration waveform is lower than 4.2MHz, it is determined that the individual abnormality has occurred. The individual abnormality detection selects only 1 dimension of the series resonance frequency Fs, sets the detection index in the selected 1 dimension to be 5MHz or less and 4.2MHz or more, determines that the index value is normal in the linear range of the set range, and determines that the individual abnormality is outside the range. In other words, the detection of the individual abnormality can be said to be detection using only the magnitude relationship between the sample of the series resonance frequency Fs and the index value. In this case, the method is also applicable to a noise reduction method in which the index value is multi-step, or the abnormality rate per hour of the sample group is used as described in patent document 3.

In contrast, in the first embodiment, two indexes of the first detection index and the second detection index are used for the determination. That is, a two-dimensional detection index space surrounded by a rectangular shape is used for the determination. The determination unit 25 determines whether or not each sample is located in a plane serving as a detection index space by logical operation, and assigns a state indicating whether or not each sample is normal or abnormal to each sample.

The state assigning process is a sequential process obtained in time series of samples. The shape of the space shown in the detection index space is not limited to a rectangular shape, and may be set to a triangular shape or an irregular shape according to the selected detection index or index value. For example, the second detection index corresponding to the equivalent series resistance R1 is set to 20 Ω to 50 Ω in 5MHz, and 30 Ω to 80 Ω in 4.2MHz, and is formed as a trapezoidal detection index space corresponding to a tendency of the equivalent series resistance R1 to change in one direction with deposition. Thus, the optimum detection sensitivity can be maintained even in any deposition state. In the present embodiment, the results of the determination by the determination section 25 are sequentially output via the detection section 26.

As described above, if the configuration uses the detection index space having two or more dimensions, it is possible to detect measurement abnormalities for a plurality of dimensions. In the configuration in which the one-dimensional detection index space having only the series resonance frequency Fs is set as in the conventional example, a sample having an abnormal film quality, which is a result of only the variation in the equivalent series resistance R1 shown in fig. 4, cannot be detected as a measurement abnormality. Even if the abnormality rate per hour is used for the series resonance frequency, the film quality abnormality shown in fig. 4 and indicated between 4.4MHz and 4.5MHz cannot be detected as a measurement abnormality, and even measured as a normal measurement. This is because the variation in the equivalent series resistance R1 is not correlated with the variation in the time region of the series resonance frequency Fs. On the other hand, if the two-dimensional detection index space is configured using the region in which the equivalent series resistance R1 is used in addition to the series frequency region, the sample with abnormal membranous shown in fig. 4 can be detected as a measurement abnormality. The physical quantity used as an index for determining a measurement abnormality can be appropriately selected according to a requirement such as sensitivity determined as a measurement abnormality, for example, according to a measurement abnormality occurring, such as a membranous abnormality.

< second embodiment >

In the example shown in fig. 4, a second embodiment is included in which the deposit is aluminum. In the second embodiment, the same detection as in the first embodiment is performed except that a two-dimensional detection index space having a polygonal boundary imitating a curve or a two-dimensional detection index space having a curved boundary is set instead of the detection index space described in the first embodiment. Hereinafter, a detection index space different from that of the first embodiment will be described.

In the first embodiment, the first detection index and the second detection index are set to 4 groups of coordinate points at maximum, while in the second embodiment in which a polygonal-shaped boundary or a curved boundary that imitates a curve is set, 3 or more values are set as the first detection index, and coordinate points exceeding 4 groups are spatially specified as the detection index. Hereinafter, the first detection index that sets the polygonal boundary or the curved boundary that simulates a curve is also referred to as a curved index.

Hereinafter, a method of calculating the curved index will be described.

For example, an index function expressed as equivalent series resistance R1 ═ f (series resonance frequency) is derived in advance using a storage elastic modulus G' of aluminum, which is a physical parameter of 26GPa, and a loss elastic modulus G ″ of aluminum, which is 0.2 GPa. The above equation and the like are used for deriving the index function. The controller 20 uses the index function to perform scanning in the range of 5MHz or less and 4.2MHz or more, which is the range of the first detection index, and calculates the equivalent series resistance value at each frequency. The broken line shown in fig. 4 indicates a coordinate trajectory at the time of range scanning of the first detection index.

Since the broken line shown in fig. 4 is a calculated value based on the physical parameter, the controller 20 sets the allowable range of variation to, for example, ± 10% of the calculated value. That is, 1.1 times the value indicated by the broken line in fig. 4 is set as a curved indicator indicating the upper limit of the first detection indicator, and 0.9 times the value indicated by the broken line in fig. 4 is set as a curved indicator indicating the lower limit of the first detection indicator.

In the second embodiment, the detection index is defined as a multiple of a Scalar (Scalar) value with respect to a dimension of the equivalent series resistance, but the perturbation direction of the broken line allowing the variation may include a dimension on the series resonance frequency side. That is, the amount of shooting may be defined by a vector value. Thus, even when the tendency of fluctuation spans 2 dimensions, the detection of the measurement abnormality can be performed more accurately. Further, since the detection index space is set without requiring various experiments, the work for setting the detection index space can be simplified. In addition, by combining the experiment result performed in advance with the calculated value, the perturbation amount becomes clear, and the accuracy of determination of the measurement abnormality can be further improved.

Even if the detection is performed by setting the detection index space having the boundary indicated by the curved index, the sample example of the membranous abnormality shown in fig. 4 can be detected as a measurement abnormality. For example, as in the conventional example, in the configuration in which only the one-dimensional detection index space of the equivalent series resistance R1 is set and the one-dimensional detection index space is 20 Ω to 700 Ω, the sample with the membranous abnormality shown in fig. 4 cannot be detected as a measurement abnormality. Even when the range in which the equivalent series resistance R1 is 50 Ω or less is set as the detection index space, a sample with a membranous abnormality in which the equivalent series resistance R1 is 100 Ω can be detected as a measurement abnormality, but a normal sample with a series resonance frequency Fs of 4.6MHz or less is detected as a measurement abnormality. As a result, the lifetime of the crystal oscillator, i.e., the usable period, is significantly shortened. In contrast, in the configuration using the detection index space having the boundary indicated by the curved index, in other words, the detection index space having the curved boundary, even if the deposit is an aluminum film, the normal sample and the abnormal sample in fig. 4 can be clearly distinguished.

< third embodiment >

In the third embodiment, a case where a region where the loss elastic modulus G ″ can be ignored, that is, a region where the complex elastic modulus G, the storage elastic modulus G', and the loss elastic modulus G ″ hardly fluctuate with respect to the intrinsic value of the crystal oscillator even if the film formation material is deposited on the crystal oscillator, is described as a range of the first detection index. In the third embodiment, the density ρ of the deposit is determined_fAn index function expressed as equivalent series resistance R1 ═ f (series resonance frequency) was derived as a value of an organic material as a film forming material.

The controller 20 scans the range of the first detection index using the index function, and calculates the equivalent series resistance value for each frequency. The straight line shown in fig. 5 indicates a coordinate trajectory when scanning is performed in the first detection index range. The controller 20 perturbs the straight line shown in fig. 5 in the same manner as in the second embodiment, and sets a rectangular detection index space by combining the first detection index with the straight line. Then, the control device 20 detects a measurement abnormality using the detection index space thus set.

In addition, in terms of density ρ of deposit_fIn the configuration in which the detection index space is set, the density ρ of the deposit can be set_fTo gold or aluminum. That is, the density ρ of the deposit can be changed_fA two-dimensional detection index space is selected. That is, in other words, the detection index space can be selected by utilizing the density ρ of the deposit_fAnd equivalent series resistance R1 and series resonance frequency Fs, and a two-dimensional detection index space corresponding to the type of deposit is selected. In this way, the detection index space is not limited to two dimensions, and can be appropriately used for a space having three or more dimensions.

< fourth embodiment >

In the fourth embodiment, the dimension used as the detection index space of the second embodiment is changed from the series resonance frequency Fs to the film thickness. The fourth embodiment then detects a measurement abnormality using a two-dimensional detection index space having a polygonal boundary imitating the same curve as in the second embodiment or a two-dimensional detection index space having a curved boundary.

First, an index function expressed as equivalent series resistance f (film thickness) is derived. In the derivation of the index function, the same conditions as in the second embodiment are used. That is, a function corresponding to a change in the deposition amount of aluminum and a change in the equivalent series resistance R1 is derived as an index function. The controller 20 scans the range of the first detection index, that is, the range of the film thickness using the index function, and calculates the value of the equivalent series resistance in each film thickness. The dotted line shown in fig. 6 indicates the coordinate trajectory when scanning using the index function. Next, the control device 20 sets the first detection index. The first detection index may be calculated by an experiment performed in advance, but is 0 μm or more and 60 μm or less under the same conditions as in the second embodiment. The range of the film thickness is a value corresponding to 5MHz or less and 4.2MHz or more of the first detection index of the second embodiment. Next, the control device 20 sets a detection index space for perturbing the broken line in fig. 6. Thereafter, the procedure for detecting the measurement abnormality is the same as in the second embodiment.

That is, the fourth embodiment is substantially the same in the first detection index and the second detection index as compared with the second embodiment, and is different from the second embodiment in that the dimension constituting the detection index space is one-dimensional. Specifically, the series resonance frequency Fs constituting the detection index space of the second embodiment is replaced with the film thickness in the fourth embodiment. Then, since the detection index space in the fourth embodiment is a case where aluminum is used as the physical parameter, it can be used when the deposit is aluminum.

Here, as shown by the dotted line in fig. 6, in a space having dimensions of the film thickness and the equivalent series resistance, a normal sample and an abnormal sample of the film quality are shown in which aluminum is a deposit, and silver and tris (8-hydroxyquinoline) aluminum (Alq) are shown in addition to these samples₃) As a normal sample of the deposit. In this example, the normal sample is considered to be: the first detection index is 0 μm or more and 20 μm or less, and the second detection index is the same as the first detection indexThe same ranges were used in the examples. Then, the coordinate value of the sample regarded as the membranous abnormality is far from the second detection index.

As described above, the perturbation in the fourth embodiment may be performed so long as the above-described mode is satisfied, and although it is sufficient to use the detection index space of aluminum as the physical parameter, it is sufficient to perform determination using the detection index space, and detection of measurement abnormality can be performed also for gold, silver, and tris (8-hydroxyquinoline) aluminum (Alq3) which is an organic substance. Further, since the detection of the measurement abnormality can be performed with respect to the deposits having different densities from each other, the measurement abnormality can be determined without increasing the number of calculation steps of the control device 20.

As described above, the following effects can be obtained in the above embodiment.

(1) Since abnormality determination is performed using a detection index space of two or more dimensions, it is possible to detect a measurement abnormality that cannot be detected by a one-dimensional detection index.

(2) In a structure including the film thickness in the dimension constituting the detection index space, the measurement abnormality can be determined whether the deposit is a relatively hard film or a relatively soft film.

(3) Since the equivalent series resistance R1 and the series resonance frequency Fs are dimensions that respectively strongly respond to a change in mass of deposits deposited on the crystal oscillator, it can be considered that the detection device is suitable for detecting a measurement abnormality depending on a change in mass even in a detection index space including at least 1 of the series resonance frequency Fs and the equivalent series resistance R1.

(4) The density ρ is measured when a relatively soft film in which the internal friction and the complex elastic modulus contribute to the equivalent series resistance R1 is a measurement target, or when a relatively hard film in which the internal friction and the complex elastic modulus do not contribute to the equivalent series resistance R1 is a measurement target_fAre all dimensions that respond directly to the change in mass of the deposit deposited on the crystal oscillator. Therefore, the inclusion density ρ is used_fThe structure of the three-dimensional detection index of (1) can be regarded as particularly suitable for determining whether or not a change occurs depending on the qualityThe measurement abnormality of (2) is detected.

(5) In the case of a structure including the density of the film in the dimension constituting the detection index space, the common detection index space can be applied to both the case where the deposit is a relatively hard film and the case where the deposit is a relatively soft film.

(6) In the case of a configuration in which the series resonance frequency Fs and the half-value frequencies F1 and F2 are used as the resonance characteristic values for obtaining the sample group, the above expression 2 can be used, and therefore, the range of the dimension for expressing the detection index can be expanded as compared with the case of using only the above expression 1.

< other embodiments >

The dimensions constituting the detection index space may be the series resonance frequency Fs and the equivalent series resistance R1, or a D value, and an equivalent series resistance R1 obtained from the series resonance frequency Fs and a half-value bandwidth. The dimensions for expressing the detection index may be two or more selected from the group consisting of the series resonance frequency Fs, the equivalent series resistance R1, the Q value, the half width at half maximum, the film thickness, and the value of the current flowing in the crystal oscillator. For example, the first detection index value may be 1 value out of a group consisting of the series resonance frequency Fs, the equivalent series resistance R1, the Q value, the half width at half maximum, the film thickness, and the value of the current flowing into the crystal oscillator, and the second detection index value may be 1 value out of the first detection index values in the same group. In this case, from the viewpoint of improving the accuracy of detection of the measurement abnormality, it is preferable to select a group of variables in which the second detection index value greatly changes from the first detection index value.

In addition, for example, as a measure against noise, the detection unit 26 adds a time delay element to detect a measurement abnormality. An example of the additional time delay element is a so-called primary time delay element that is given to perform determination when determining a state of sequential processing in time series. Specifically, when the detection unit 26 receives a predetermined number of samples each time, the predetermined number of samples giving a state indicating that a sample is abnormal, the detection unit 26 determines that a measurement abnormality has occurred. In addition, when it is desired to improve the temporal detection sensitivity with respect to the selected index, the dimensional direction of the index may be subjected to detection processing as immediate judgment without adding the above-described primary delay element or the like. That is, the technical idea of the present invention can be performed as an appropriate noise countermeasure in each dimension.

Description of the symbols

C1 dynamic capacitor

Fs series resonance frequency

F1, F2 half-value frequency

Fw is half-value frequency width

L1 dynamic inductor

R1 equivalent series resistance

11 vacuum tank

12 vapor deposition source

13 power supply

14 detection device

20 control device

21 a control part

22 storage section

23 measuring section

23A first measuring section

23B second measurement unit

24 abnormality detection unit

25, a determination section

26: a detection unit.