Analytical device, analytical method, and analytical program

Abstract

To monitor a processing amount to a processed material with high accuracy.SOLUTION: An analyzing device comprises: a measurement part 2 that measures a concentration or a partial pressure of a reaction product generated when processing a processed material W; and a calculation part 3 that calculates the processing amount to the processed material W by using an output value of the measurement part 2. The measurement part 2 includes: a laser beam source 22 that irradiates a laser beam to a measurement object gas containing the reaction product; a light detection device 23 that detects the laser beam penetrating a measurement object gas; and a signal processing part 242 that calculates the concentration or the partial pressure of the reaction product on the basis of a detection signal of the light detection device 23. The calculation part 3 includes: a time integration part 32 that calculates a time integration value obtained by performing a time integration of an output value of the measurement part 2; a relation data storage part 31 that stores a relation data indicating a relation between a time integration value obtained by performing the time integration of the output value of the measurement part 2 and the processing amount to the processed material; and a processing amount calculation part 33 that calculates the processing amount to the processed material from the time integration value obtained by the time integration part 32 and the relation data.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an analytical device, an analytical method, and an analytical program used in processes such as semiconductor processes. [Background technology]

[0002] Conventionally, in semiconductor processes, for example, to monitor the end point (etching depth) in an etching process, a plasma emission monitor (OES; Optical Emission Spectrometer) that detects plasma emission during the process, as shown in Patent Document 1, has been used.

[0003] However, because OES detects plasma emission generated by the action of plasma, it cannot be used in etching processes that do not use plasma. Furthermore, OES output values ​​vary from process to process, day to day, and even individual device to device due to individual differences in the process chamber and OES, installation position errors, window contamination due to process gases and reaction products, and the state of the luminescent species. For this reason, OES cannot obtain data with good reproducibility, and the endpoint is determined by using OES output values ​​relatively and observing the trend of their change.

[0004] In addition, analyzers using non-dispersive infrared (NDIR) are used to monitor endpoints. However, NDIR analyzers lack the resolution (sensitivity) to accurately measure endpoints. In particular, as semiconductors have become increasingly miniaturized in recent years, measurement errors due to insufficient resolution (sensitivity) increase as semiconductor nodes (minimum line widths) become smaller. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-170812 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and its main object is to accurately monitor the amount of processing of a workpiece in a process for processing the workpiece. [Means for solving the problem]

[0007] That is, the analytical apparatus according to the present invention comprises a measurement unit that measures the concentration, partial pressure, or values ​​related thereto of reaction products generated when a workpiece is treated in a process for treating the workpiece, and a calculation unit that calculates the processing amount for the workpiece using an output value of the measurement unit, wherein the measurement unit has a laser light source that irradiates a measurement target gas containing the reaction products with laser light, a photodetector that detects the laser light that has transmitted through the measurement target gas, and a signal processing unit that calculates the concentration, partial pressure, or values ​​related thereto of the reaction products based on a detection signal from the photodetector, and the calculation unit has a time integration unit that calculates a time integral value obtained by integrating the output value of the measurement unit over time, a relationship data storage unit that stores relationship data showing the relationship between the time integral value obtained by integrating the output value of the measurement unit over time and the processing amount for the workpiece, and a processing amount calculation unit that calculates the processing amount for the workpiece from the time integral value obtained by the time integration unit and the relationship data.

[0008] With this analytical device, the reaction products generated when the workpiece is treated in the process of treating the workpiece are measured by laser spectroscopy, so the concentration, partial pressure, and values ​​related to these of the reaction products can be measured with high accuracy.The amount of treatment for the workpiece is calculated using the relationship between the time integral value obtained by integrating the output value of the measurement unit over time and the amount of treatment for the workpiece, so the amount of treatment for the workpiece can be monitored with high accuracy.

[0009] It is preferable that the calculation unit further includes a processing determination unit that determines whether the processing speed for the workpiece has changed based on a change over time in the output value of the measurement unit. With this configuration, for example, when the same film or substance is being treated, if the output value of the measuring unit changes, it can be determined that the treatment speed of the film or substance has changed.

[0010] As described above, in a semiconductor process such as an etching process, it is conceivable that the processing speed (etching rate) of the workpiece varies within the surface. In order to calculate this variation within the surface, it is desirable that the calculation unit further includes a variation calculation unit that calculates the variation in the processing amount within the surface of the workpiece based on the time change in the output value of the measurement unit.

[0011] In order to measure the concentration, partial pressure or values ​​related thereto of the reaction product with even greater accuracy by multi-reflection laser spectroscopy, it is desirable that the measurement unit further includes a multi-reflection mirror, the laser light source causes laser light to be incident between the multi-reflection mirrors, and the photodetector detects the light emitted from between the multi-reflection mirrors.

[0012] For example, in a semiconductor process such as an etching process, it is conceivable that the processing speed (etching rate) of the workpiece varies within the surface. The in-plane distribution of this processing speed can be determined by the generation of reaction products, which can be determined from the output value of the measurement unit. Therefore, it is desirable that the calculation unit further includes a uniformity determination unit that determines the uniformity of the processing amount for the workpiece based on the time change of the output value of the measurement unit.

[0013] In a specific embodiment, the uniformity determining unit may determine the uniformity of the amount of processing for the workpiece based on the gradient of the time change in the output value of the measuring unit. For example, consider a case where a workpiece has a first layer and a second layer below the first layer, and the amount of reaction products generated per unit time by etching the first layer is different from the amount of reaction products generated per unit time by etching the second layer. In this case, if the in-plane distribution of the etching rate is highly uniform, the magnitude of the slope in the time change of the output value of the measurement unit will be large when the layer to be etched changes from the first layer to the second layer. On the other hand, if the in-plane distribution of the etching rate is low, the magnitude of the slope in the time change of the output value of the measurement unit will be small when the layer to be etched changes from the first layer to the second layer.

[0014] In order to reduce error factors due to components adhering inside the process chamber, contamination of the optical window, etc., and to measure the reaction products with high accuracy, it is desirable that the measurement unit has a zero calibration function that performs zero calibration when no processing is being performed on the workpiece. More specifically, it is desirable that the measurement unit has a zero calibration function that performs zero calibration when no reaction products are present in the process chamber, for example, (1) when no processing is being performed on the workpiece and the process chamber is evacuated, or (2) when no processing is being performed on the workpiece and an inert gas such as nitrogen or argon is flowing into the process chamber.

[0015] The laser light source may be a semiconductor laser, and this semiconductor laser is preferably a quantum cascade laser. Quantum cascade lasers are the only practical semiconductor lasers capable of oscillating at wavelengths in the mid-infrared region at room temperature, and because many gas molecules have significant absorption in the mid-infrared region, they can be used to improve analytical instruments.

[0016] Furthermore, one possible method for creating the relationship data for the above-mentioned analytical device is to use, for example, an ellipsometer to measure the processing amount at multiple points on the processed workpiece, and then find the correlation between the average processing amount at those multiple points and the time integral value of the output value of the measurement unit. However, it is necessary to measure the amount of processing at a plurality of points, which not only makes the work complicated but also may cause errors due to averaging. Therefore, the method for creating relational data for an analytical device according to the present invention is characterized in that it processes the object to be treated in a process for treating the object to be treated, calculates a time integral value by integrating the output value of the measurement unit over time, calculates the processing amount from the weight of the processed object to be treated, and generates the relational data from the calculated time integral value and the calculated processing amount.

[0017] According to this method for creating relational data for an analytical device, the processing volume is calculated from the weight of the processed object, which makes it easy to create relational data and also enables accurate relational data to be created.

[0018] Furthermore, the analytical method according to the present invention is an analytical method using a measurement unit that measures the concentration, partial pressure, or values ​​related thereto of reaction products generated when a workpiece is treated in a process for treating the workpiece, and the measurement unit has a laser light source that irradiates laser light onto a gas to be measured that contains the reaction products, a photodetector that detects the laser light that has passed through the gas to be measured, and a signal processing unit that calculates the concentration, partial pressure, or values ​​related thereto based on the detection signal of the photodetector, and is characterized in that it calculates a time integral value by integrating the output value of the measurement unit over time, and calculates the processing amount for the workpiece using relationship data that shows the relationship between the time integral value by integrating the output value of the measurement unit over time and the processing amount for the workpiece.

[0019] In addition, the analytical program according to the present invention is an analytical program used in an analytical device having a measurement unit that measures the concentration, partial pressure, or values ​​related thereto of reaction products produced when a workpiece is treated in a process for treating the workpiece, and is an analytical program for calculating a processing amount for the workpiece using an output value of the measurement unit, wherein the measurement unit has a laser light source that irradiates a measurement target gas containing the reaction products with laser light, a photodetector that detects the laser light that has passed through the measurement target gas, and a signal processing unit that calculates the concentration, partial pressure, or values ​​related thereto of the reaction products based on the detection signal of the photodetector, and the analytical program causes a computer to perform the functions of a time integration unit that calculates a time integral value obtained by integrating the output value of the measurement unit with respect to time, a relationship data storage unit that stores relationship data showing the relationship between the time integral value obtained by integrating the output value of the measurement unit with respect to time and the processing amount for the workpiece, and a processing amount calculation unit that calculates the processing amount for the workpiece from the time integral value obtained by the time integration unit and the relationship data. [Effects of the Invention]

[0020] According to the present invention configured as described above, it is possible to accurately monitor the amount of material being processed in a process for processing the material. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram illustrating an analysis device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a functional configuration diagram of a signal processing device and a calculation unit of the measurement unit in the embodiment. [Figure 3] 3A and 3B are schematic diagrams showing a method for modulating a laser oscillation wavelength in the embodiment. [Figure 4] 10 is a time series graph showing an example of the oscillation wavelength, the light intensity I(t), the logarithmic intensity L(t), the feature signal Fi(t), and the correlation value Si in the embodiment. [Figure 5] FIG. 10 is a diagram showing a concept of concentration or partial pressure calculation using a single correlation value and a sample correlation value according to the embodiment. [Figure 6] 10 shows experimental results showing the correlation between the output value of the measuring unit of the embodiment and the etching rate, and the correlation between the output value of a conventional plasma optical emission monitor (OES) and the etching rate. [Figure 7] FIG. 10 is a functional configuration diagram of a signal processing device and a calculation unit of a measurement unit according to a modified embodiment. [Figure 8] FIG. 10 is a diagram showing the respective stages of etching in the modified embodiment and the output values ​​of the measurement unit at each stage. [Figure 9] 10A is a functional configuration diagram of a calculation unit of a modified embodiment, and FIG. 10B is a diagram for explaining processing determination. [Figure 10] 10A is a functional configuration diagram of a calculation unit of a modified embodiment, and FIG. 10B is an explanatory diagram of variation calculation. [Figure 11] FIG. 10 is a diagram showing a method for calculating an etching end point (endpoint) in a modified embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of an analyzer according to the present invention will be described below with reference to the drawings. In addition, in all of the drawings shown below, for the sake of clarity, some parts are omitted or exaggerated as appropriate, and the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0023] The analytical device 100 according to this embodiment is for monitoring the etching depth of an etched workpiece W. The analytical device 100 measures the concentration, partial pressure, or a value related thereto of a reaction product generated when the workpiece W is etched, and calculates the etching depth using an output value indicating the concentration, partial pressure, or a value related thereto.

[0024] 1, the analysis device 100 is installed in an exhaust pipe H of a process chamber PC where etching is performed, and is configured to analyze reaction products contained in a gas (hereinafter referred to as a measurement target gas) flowing through the exhaust pipe H. In this embodiment, a turbomolecular pump TMP and a dry pump DP are installed in the exhaust pipe H, and the analysis device 100 is installed between the turbomolecular pump TMP and the dry pump DP, but this is not limiting.

[0025] Specifically, as shown in Figures 1 and 2, the analytical device 100 includes a measurement unit 2 that measures the concentration, partial pressure, or values ​​related to these of reaction products generated when the workpiece W is etched, and a calculation unit 3 that calculates the etching depth of the workpiece W using the output value of the measurement unit 2.

[0026] <Configuration of measurement unit 2> The measurement unit 2 continuously measures the concentration of reaction products (here, SiF4) contained in the gas to be measured, and uses, for example, infrared laser absorption modulation (IRLAM (Infrared Laser Absorption Modulation)) (see Patent No. 6886507).

[0027] Specifically, as shown in FIGS. 1 and 2, the measurement unit 2 includes a measurement cell 21 having a pair of multi-reflection mirrors M1 and M2 sandwiching the gas to be measured, a semiconductor laser 22 that irradiates the measurement cell 21 with laser light and causes the laser light to enter between the pair of multi-reflection mirrors M1 and M2, a photodetector 23 that detects the laser light that is emitted from between the pair of multi-reflection mirrors M1 and M2 and passes through the measurement cell 21, and a signal processing device 24 that calculates the concentration or partial pressure of the reaction product based on the detection signal of the photodetector 23.

[0028] The measurement cell 21 is a so-called Herriott cell that has a pair of multi-reflection mirrors M1 and M2 provided therein and thereby multiple-reflects the laser light. Note that, in addition to the Herriott cell, the measurement cell 21 may be a White cell having multiple multi-reflection mirrors provided on either side of the gas to be measured, or a ring cell having an annular multi-reflection mirror surrounding the gas to be measured.

[0029] The semiconductor laser 22 is a quantum cascade laser. A quantum cascade laser is a semiconductor laser that uses intersubband transitions due to a multi-stage quantum well structure, and oscillates laser light of a specific wavelength in the wavelength range of approximately 4 μm to approximately 20 μm. This semiconductor laser 22 is capable of modulating (changing) the oscillation wavelength by applying a current (or voltage).

[0030] Here, the photodetector 23 is a thermal type such as a relatively inexpensive thermopile, but other types, such as quantum photoelectric elements with good responsiveness such as HgCdTe, InGaAs, InAsSb, PbSe, etc., may also be used.

[0031] The signal processing device 24 comprises analog electrical circuits consisting of buffers, amplifiers, etc., digital electrical circuits consisting of a CPU, memory, etc., and AD converters, DA converters, etc. that mediate between these analog and digital electrical circuits.

[0032] 2, the signal processing device 24 functions as a light source control unit 241 that controls the output of the semiconductor laser 22, and a signal processing unit 242 that receives a detection signal from the photodetector 23 and processes the received signal to calculate the concentration, partial pressure, or a value related thereto of the component to be measured. Note that the value related to the concentration or partial pressure includes a value correlated with the concentration or partial pressure, such as absorption intensity.

[0033] Each unit will be described in detail below, taking as an example the case where the signal processing unit 242 calculates the concentration of the component to be measured.

[0034] The light source control unit 241 controls the current source (or voltage source) of the semiconductor laser 22 by outputting a current (or voltage) control signal. Specifically, the light source control unit 241 changes the drive current (or drive voltage) of the semiconductor laser 22 at a predetermined frequency, and modulates the oscillation wavelength of the laser light output from the semiconductor laser 22 at a predetermined frequency with respect to the center wavelength (see FIG. 3). This causes the semiconductor laser 22 to emit modulated light modulated at a predetermined modulation frequency.

[0035] In this embodiment, the light source control unit 241 changes the drive current to a triangular wave shape, and modulates the oscillation frequency to a triangular wave shape (see "Oscillation Wavelength" in FIG. 4). In practice, the drive current is modulated using a different function so that the oscillation frequency becomes a triangular wave shape. Also, as shown in FIG. 3, the oscillation wavelength of the laser light is modulated with the peak of the optical absorption spectrum of the component to be measured as the center wavelength. Alternatively, the light source control unit 241 may change the drive current to a sine wave shape, a sawtooth wave shape, or any other function shape, and modulate the oscillation frequency to a sine wave shape, a sawtooth wave shape, or any other function shape.

[0036] The signal processing unit 242 includes a logarithmic calculation unit 242a, a correlation value calculation unit 242b, a storage unit 242c, a concentration calculation unit 242d, and the like.

[0037] The logarithmic calculation unit 242a performs logarithmic calculation on the light intensity signal, which is the detection signal of the photodetector 23. The function I(t) showing the time-series change of the light intensity signal obtained by the photodetector 23 is shown as "light intensity I(t)" in Fig. 4, and by performing logarithmic calculation, it becomes shown as "logarithmic intensity L(t)" in Fig. 4.

[0038] The correlation value calculation unit 242b calculates correlation values ​​between an intensity-related signal related to the intensity of sample light obtained when measuring the measurement target gas and a plurality of predetermined feature signals. A feature signal is a signal for extracting waveform features of the intensity-related signal by correlating it with the intensity-related signal. The feature signal can be, for example, a sinusoidal signal or any other signal that matches the waveform feature to be extracted from the intensity-related signal. Here, the correlation value calculation unit 62 uses a logarithmically calculated light intensity signal (logarithmic intensity L(t)) as the intensity-related signal.

[0039] Furthermore, the correlation value calculation unit 242b calculates a number of characteristic signals F that is greater than the total number of types of measurement target components (reaction products in this embodiment) and the number of types of interference components. i (t) (i=1, 2, . . . , n), a plurality of sample correlation values ​​S, which are correlation values ​​between the intensity-related signal of the sample light and each of the plurality of feature signals, are calculated by the following equation (1): i where T in Equation 1 is the modulation period.

[0040]

number

[0041] When calculating the sample correlation value, the correlation value calculation unit 242b calculates the sample correlation value by using the intensity-related signal L(t) of the sample light and the plurality of feature signals F as shown in Equation 1. i (t) and the correlation value S i from the reference light intensity related signal L0(t) and multiple feature signals F i (t) is the correlation value with the reference correlation value R i The corrected sample correlation value S i It is desirable to calculate '. This removes the offset contained in the sample correlation value, resulting in a correlation value proportional to the concentrations of the component to be measured and the interfering component, thereby reducing measurement errors. Note that a configuration may be adopted in which the reference correlation value is not subtracted.

[0042] Here, the timing of acquiring the reference light may be simultaneous with the sample light, before or after measurement, or at any other timing. The intensity-related signal or reference correlation value of the reference light may be acquired in advance and stored in the storage unit 242c. In addition, one possible method of simultaneously acquiring the reference light is to provide two photodetectors 23, split the modulated light from the semiconductor laser 22 using a beam splitter or the like, and use one for measuring the sample light and the other for measuring the reference light.

[0043] In this embodiment, the correlation value calculation unit 242b calculates the correlation value based on a plurality of feature signals F i For (t), a function that more easily captures the waveform characteristics of the logarithmic intensity L(t) than a sine function is used. For sample gas containing the target component and one interfering component, two or more feature signals F1(t) and F2(t) may be used. For example, the two feature signals F1(t) and F2(t) may be a function based on a Lorentzian function that approximates the shape of the absorption spectrum, and a differential function of the Lorentzian function. Furthermore, instead of a function based on a Lorentzian function, a function based on a Voigt function or a Gaussian function may also be used as the feature signal. Using such a function as the feature signal can obtain a larger correlation value than when a sine function is used, thereby improving measurement accuracy.

[0044] Here, it is desirable to remove the DC component from the feature signal, i.e., to adjust the offset so that it becomes zero when integrated over the modulation period. This makes it possible to eliminate the effect of an offset on the intensity-related signal due to fluctuations in light intensity. Note that instead of removing the DC component from the feature signal, the DC component may be removed from the intensity-related signal, or the DC components may be removed from both the feature signal and the intensity-related signal. Alternatively, the feature signal may be a sample value of the absorption signal of the measurement target component and / or interference component, or a value simulating either of them.

[0045] By using two feature signals F1(t) and F2(t) as orthogonal function sequences or function sequences close to orthogonal function sequences, the features of the logarithmic intensity L(t) can be extracted more efficiently, and the concentration obtained by the simultaneous equations described later can be more accurately calculated.

[0046] The storage unit 242c stores the intensity-related signals and the plurality of characteristic signals F when the measurement target component and each interference component are present alone. i The individual correlation values, which are the correlation values ​​per unit concentration of the measurement target component and each interfering component, calculated from (t), are stored. i (t) is a plurality of feature signals F used in the correlation value calculation unit 242b. i It is the same as (t).

[0047] Here, when storing the single correlation value, the storage unit 242c desirably subtracts the reference correlation value from the correlation value when the measurement target component and each interference component are present alone, and then stores the corrected single correlation value converted to a value per unit concentration. This removes the offset contained in the single correlation value, resulting in a correlation value proportional to the concentrations of the measurement target component and interference components, thereby reducing measurement errors. Note that a configuration in which the reference correlation value is not subtracted is also possible.

[0048] The concentration calculation section 242d calculates the concentration of the measurement target component using the plurality of sample correlation values ​​obtained by the correlation value calculation section 242b.

[0049] Specifically, concentration calculation unit 242d calculates the concentration of the component to be measured based on the plurality of sample correlation values ​​obtained by correlation value calculation unit 242b and the plurality of single correlation values ​​stored in storage unit 242c. More specifically, concentration calculation unit 242d calculates the concentration of the component to be measured by solving simultaneous equations consisting of the plurality of sample correlation values ​​obtained by correlation value calculation unit 242b, the plurality of single correlation values ​​stored in storage unit 242c, and the concentrations of the component to be measured and each interfering component. Note that Fig. 5 shows a conceptual diagram of concentration or partial pressure calculation using the single correlation values ​​and sample correlation values ​​in concentration calculation unit 242d.

[0050] When the measurement target gas contains one measurement target component (here, SiF4) and one interference component, the concentration calculation unit 242d calculates the sample correlation values ​​S1' and S2' calculated by the correlation value calculation unit 242b and the single correlation value s 1t , s 2t , s 1i , s 2i and the concentration C of the target component and each interfering component tar , C int Solve the following simultaneous equations with two unknowns: 1t is the single correlation value of the measurement target component in the first feature signal, s 2t is the single correlation value of the measured component in the second feature signal, s 1i is the single correlation value of the interference component in the first feature signal, s 2i is the single correlation value of the interference component in the second feature signal.

[0051]

number

[0052] This allows the concentration C of the measurement target component (reaction product) with interference effects removed to be calculated by a simple and reliable calculation of solving the simultaneous equations in the above formula (Equation 2). tar can be determined.

[0053] Even when it is assumed that two or more interfering components are present, the concentration of the component to be measured, with the effects of interference removed, can be determined by adding a single correlation value equal to the number of interfering components and solving a system of equations with the same number of elements as the number of component types.

[0054] <Configuration of Calculation Unit 3> Next, we will explain the calculation unit 3, which calculates the etching depth of the workpiece W using the output value of the measurement unit 2. Here, the output value of the measurement unit 2 is the concentration of the reaction product obtained by the signal processing unit 242 or a value related to the concentration.

[0055] The calculation unit 3 comprises analog electrical circuits consisting of buffers, amplifiers, etc., digital electrical circuits consisting of a CPU, memory, etc., and AD converters, DA converters, etc. that mediate between these analog and digital electrical circuits.

[0056] The calculation unit 3 has a relational data storage unit 31 that stores relational data for determining the etching depth (amount of processing), a time integration unit 32 that calculates a time integral value obtained by integrating the output value of the measurement unit 2 over time, and a depth calculation unit (amount of processing) 33 that calculates the etching depth (amount of processing) from the time integral value obtained by the time integration unit 32 and the relational data, as shown in FIG. 2, by the CPU and its peripheral devices working together in accordance with a predetermined analysis program stored in a predetermined area of ​​the memory.

[0057] The relational data storage unit 31 stores relational data indicating the relationship between the etching depth and a time integral value obtained by time-integrating the output value of the measurement unit 2. This relational data is created in advance and stored in the relational data storage unit 31.

[0058] Here, a method for creating the relationship data will be described. First, the workpiece W is etched, and the output value of the measuring unit 2 is time-integrated (0 to t1) to obtain a time-integrated value G t1 Calculate.

[0059] The weight W of the etched workpiece W t1Measure the difference from the initial weight W0 (W0-W t1 Then, the etching depth d is calculated using the density ρ of the processed object (etched film) and the area A of the etched region by the following formula. d t1 =(W0-W t1 ) / (ρ×A)

[0060] Next, the calculated time integral value G t1 and the calculated etching depth d t1 As described above, this relational data is generated from a set of data (G t1 ,d t1 ) or multiple sets of data (G t1 ,d t1 )~(G tn ,d tn ) It is also conceivable that the relational data may be created in advance according to the type of layer structure, material, etc. of the workpiece W.

[0061] The time integration unit 32 receives the output value of the measurement unit 2 and integrates the output value over time to obtain a time integration value G T Here, the time integration unit 32 calculates the elapsed time T E Then, the output value of the measurement unit 2 is time-integrated. In this embodiment, the output value of the measurement unit 2 is the concentration calculated by the concentration calculation unit 242d.

[0062] The depth calculation unit (processing amount calculation unit) 33 calculates the time integral value G obtained by the time integration unit 32. T and calculates the etching depth d from the relational data stored in the relational data storage unit 31. T The etching depth d obtained by the depth calculation unit 33 is calculated. TThe etching depth d obtained by the depth calculation unit 33 may be displayed on the display unit 4 such as a display, or may be output in other ways, such as by transmitting the data to another device. In addition, the display unit 4 can display a graph showing the output value of the measurement unit 2 or its change over time, or can display the etching rate. In addition, the calculation unit 3 calculates the etching depth d obtained by the depth calculation unit 33. T The information processing device may have a notification unit that issues an alarm when a predetermined condition is met, such as when the value of the power consumption exceeds a predetermined threshold.

[0063] <Effects of this embodiment> The thus configured analyzing apparatus 100 of this embodiment uses multi-reflection semiconductor laser spectroscopy to measure the reaction products generated when etching the workpiece W, thereby enabling accurate measurement of the concentration or partial pressure of the reaction products. The etching depth is calculated using the relationship between the time integral value obtained by time-integrating the output value of the measuring unit 2 and the etching depth, enabling accurate monitoring of the etching depth.

[0064] In particular, in this embodiment, the use of an IRLAM in the measurement unit 2 can reduce the influence of interference from interfering components other than the reaction product, which is the component to be measured. As a result, the concentration of the reaction product can be measured with high accuracy, the relationship data can be made accurate, and the etching depth can be calculated with high accuracy.

[0065] 6 shows the experimental results showing the correlation between the output value of the measuring unit (IRLAM) of this embodiment and the etching rate, and the correlation between the output value of a conventional plasma optical emission monitor (OES) and the etching rate. In the "1st" and "2nd" stages, the same workpieces were etched under the same etching conditions, and the correlation between the measuring unit 2 of this embodiment and the etching rate (IRLAM vs. ER) and the correlation between the conventional plasma optical emission monitor (OES) and the etching rate (OES vs. ER) were determined for each stage.

[0066] In the measurement unit 2 of this embodiment, it is found that the correlation between the etching rate and the output value is reproducible, and that the correlation between the etching rate and the output value is always linear. Since the correlation between the etching rate and the output value is reproducible, it is also found that the correlation between the time integral value of the etching rate (etching depth) and the time integral value of the output value is reproducible. On the other hand, in a conventional plasma optical emission monitor (OES), the correlation between the etching rate and the output value is not reproducible, and in some cases, the sign (±) of the slope changes.

[0067] <Other embodiments> 7, the calculation unit 3 may further include a uniformity determination unit 34 that determines the uniformity of the etching based on the time change in the output value of the measurement unit 2. The uniformity determination unit 34 determines the uniformity of the etching based on the slope of the time change in the output value of the measurement unit 2.

[0068] When etching a workpiece having a resist film formed on a semiconductor substrate having an SiO2 film formed on a Si substrate, the output value of the measuring unit 2 (here, the partial pressure of SiF4) becomes as shown in Figure 8 due to the in-plane distribution of the etching rate.

[0069] In Figure 8, (1) and (2) indicate the state in which only the SiO2 film on the semiconductor substrate is etched, and (3) indicates the state in which not only the SiO2 film but also the Si substrate on the semiconductor substrate is etched. Furthermore, (4) and (5) indicate the state in which etching of the SiO2 film on the semiconductor substrate has finished but etching of only the Si substrate is continuing. The slope of the time change in the output value in (3) can be used to determine the uniformity of the etching. A steep slope in the time change in the output value in (3) indicates high uniformity of the in-plane distribution of the etching, while a shallow slope indicates low uniformity of the in-plane distribution of the etching.

[0070] For example, the uniformity determining unit 34 may compare the gradient of the time change in the output value resulting from a change in the layer to be etched with a predetermined threshold value to determine the uniformity of the in-plane distribution of the etching.

[0071] Furthermore, the calculation unit 3 may further include a processing determination unit 35 that determines whether the processing speed for the workpiece has changed based on the time change in the output value of the measurement unit 2.

[0072] For example, when the thickness of the film being etched is known, the process determination unit 35 determines whether the etching rate has changed based on the time change in the output value of the measurement unit 2 while the same type of film is being etched. Specifically, while the same type of film is being etched, the output value of the measurement unit 2 is expected to remain constant or approximately constant unless the etching conditions are changed. In this case, as shown in FIG. 9 , the process determination unit 35 determines that the etching rate is unstable if the output value increases or decreases by more than a predetermined value. Note that determining whether the output value is during the etching of the same type of film, rather than the output value during the transition period when the film being etched changes, can be performed by calculating the etching depth from the time integral of the output value and the relational data and comparing it with the known film thickness. In other words, if the etching depth calculated from the time integral of the output value and the relational data is smaller than the known film thickness, it can be determined that the same type of film is being etched.

[0073] Furthermore, the calculation unit 3 may further include a variation calculation unit 36 ​​that calculates the variation in the processing amount within the surface of the workpiece based on the time change in the output value of the measurement unit 2.

[0074] As shown in FIG. 10, this variation calculation unit 36 ​​can calculate the maximum etching depth and the minimum etching depth from a first stable section (etching of only the first layer) in the output value of the measurement unit 2, a transition section (etching of the first layer and the second layer below it) following the stable section, and a second stable section (etching of only the second layer) following the transition section.

[0075] Here, the maximum etching rate is x1, the minimum etching rate is x2, and the average etching rate is x ave If the end point of the first stable section is t1 and the end point of the transition section is t2, the film thickness h of the first layer can be calculated from the time integral G of the output value of the measuring unit 2, and the following relationship is obtained: t1=h / x1, t2=h / x2 From these equations, t2 / t1=x1 / x2(t2:t1=x1:x2). This allows t2:t1:t ave =x1:x2:x ave and t1, t2, x ave is known and t ave = (t1 + t2) / 2, so x1 and x2 can be calculated. ave is found by dividing the average etching depth, which is found from the time integral value and the relational data, by time, or may be found from the correlation between the etch rate and the output value. As a result, the maximum etching depth (x1×t2) and the minimum etching depth (x2×t2) can be calculated, and the variation in etching depth can be determined.

[0076] 11, the calculation unit 3 may calculate the etching end point (end point) by first or second differentiation of the output value of the measurement unit 2. Here, an example is shown in which the end point is detected when the transition period from the first layer (SiO2) to the second layer (Si) ends in a processing object having a first layer (SiO2) and a second layer (Si).

[0077] The measurement unit 2 of the above embodiment has a zero calibration function that performs zero calibration when no etching is being performed. More specifically, the measurement unit 2 has a zero calibration function that performs zero calibration when no reaction products are present in the process chamber PC, for example, when (1) no processing is being performed on the workpiece W and the process chamber PC is evacuated, or when (2) no processing is being performed on the workpiece W and an inert gas such as nitrogen or argon is being flowed into the process chamber PC. This reduces error factors due to components adhering to the inside of the process chamber PC or contamination on the optical window, and enables accurate measurement of reaction products.

[0078] Although the measurement unit 2 in the above embodiment measures the concentration of the reaction product or a value related to the concentration, it may measure the partial pressure of the reaction product in the measurement target gas or a value related to the partial pressure. In this case, the output value of the measurement unit 2 is the partial pressure of the reaction product obtained by the signal processing unit 242 or a value related to the partial pressure.

[0079] Furthermore, in the above embodiment, the measurement unit 2 is configured to be incorporated into the exhaust pipe H of the process chamber PC, but it may also be configured to be provided in a bypass pipe branching off from the exhaust pipe H, or in a measurement pipe connected to the process chamber PC separately from the exhaust pipe H. Also, a pair of multi-reflection mirrors M1, M2 may be provided inside the process chamber PC, or may be connected to an enclosing wall such as a side wall or top wall of the process chamber PC.

[0080] Furthermore, the functions of the signal processing device 24 and the calculation device 3 of the measurement device 2 in the above embodiment may be provided in one computer (information processing device).

[0081] In the above embodiment, an etching process is taken as an example of a semiconductor process, and a configuration for calculating the etching depth and the like is described, but the present invention may be applied to other semiconductor processes, such as a configuration for calculating the amount of film formation by measuring reaction products generated in a film formation process, or a configuration for calculating the amount of processing in a cleaning process of a process chamber or a workpiece such as a wafer. The present invention can also be applied to manufacturing processes for organic electroluminescence (EL) devices, solar cells, etc.

[0082] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0083] 100...Analyzer W: Workpiece 2...Measurement part M1, M2...Multi-reflection mirrors 22. Semiconductor laser (laser light source) 23. Photodetector 242 Signal processing section 3... Arithmetic section 31. Relational data storage section 32...Time integration part 33 Depth calculation unit (processing amount calculation unit) 34...Uniformity determination section

Claims

1. a measuring unit that measures the concentration, partial pressure, or values ​​related thereto of a reaction product generated when treating the object to be treated in a process of treating the object to be treated; a calculation unit that calculates a processing amount for the object to be processed using an output value of the measurement unit, The measurement unit a laser light source that irradiates a laser beam onto the measurement target gas containing the reaction product; a photodetector that detects laser light that has passed through the measurement target gas; a signal processing unit that calculates the concentration, partial pressure, or a value related thereto of the reaction product based on the detection signal of the photodetector, The calculation unit a time integration unit that calculates a time integral value by integrating the output value of the measurement unit with respect to time; a relational data storage unit that stores relational data indicating the relationship between a time integral value obtained by time-integrating the output value of the measurement unit and a processing amount for the workpiece; a processing amount calculation unit that calculates a processing amount for the workpiece based on the time integral value obtained by the time integration unit and the relationship data; and a variation calculation unit that calculates the variation in the processing amount within the surface of the workpiece based on the change over time in the output value of the measurement unit.

2. The analyzer according to claim 1 , wherein the calculation unit further comprises a process determination unit that determines whether a process speed for the object to be processed has changed based on a change over time in the output value of the measurement unit.

3. the measurement unit further includes a multi-reflection mirror, the laser light source causes laser light to be incident between the multiple reflection mirrors, 2. The analyzer according to claim 1, wherein the photodetector detects light emitted from between the multiple reflection mirrors.

4. The analyzer according to claim 1 , wherein the calculation unit further comprises a uniformity determination unit that determines the uniformity of the processing amount for the workpiece based on a change over time in the output value of the measurement unit.

5. The analyzer according to claim 4 , wherein the uniformity determination unit determines the uniformity of the amount of processing for the workpiece based on a gradient of a time change in the output value of the measurement unit.

6. The analyzer according to claim 1 , wherein the measurement unit has a zero calibration function for performing zero calibration in a state where no processing is being performed on the object to be processed.

7. the process is etching, The analytical device according to claim 1 , wherein the processing amount for the object is an etching depth.

8. A method for creating relationship data for an analytical device according to any one of claims 1 to 7, comprising: treating the object to be treated in a process for treating the object to be treated; The output value of the measurement unit is integrated over time to calculate a time integral value; Calculating the amount of treatment from the weight of the treated object; A method for creating relational data, which generates the relational data from a calculated time integral value and a calculated processing amount.

9. An analytical method using a measurement unit that measures a concentration, partial pressure, or a value related thereto of a reaction product generated when a workpiece is treated in a process of treating the workpiece, comprising: the measurement unit includes a laser light source that irradiates laser light onto the measurement target gas containing the reaction product, a photodetector that detects the laser light that has transmitted through the measurement target gas, and a signal processing unit that calculates the concentration, partial pressure, or values ​​related thereto of the reaction product based on a detection signal from the photodetector; An analysis method comprising: calculating a time integral value obtained by integrating the output value of the measurement unit over time; calculating the processing amount for the workpiece using relational data showing the relationship between the time integral value obtained by integrating the output value of the measurement unit over time and the processing amount for the workpiece; and calculating the variation in the processing amount within the surface of the workpiece based on the change over time in the output value of the measurement unit.

10. An analytical program for use in an analytical device having a measurement unit that measures a concentration, partial pressure, or a value related thereto of a reaction product generated when a workpiece is treated in a process for treating the workpiece, the program calculating a treatment amount for the workpiece using an output value of the measurement unit, The measurement unit a laser light source that irradiates a laser beam onto the measurement target gas containing the reaction product; a photodetector that detects laser light that has passed through the measurement target gas; a signal processing unit that calculates the concentration, partial pressure, or a value related thereto of the reaction product based on the detection signal of the photodetector, The analysis program a time integration unit that calculates a time integral value by integrating the output value of the measurement unit with respect to time; a relational data storage unit that stores relational data indicating the relationship between a time integral value obtained by time-integrating the output value of the measurement unit and a processing amount for the workpiece; a processing amount calculation unit that calculates a processing amount for the workpiece based on the time integral value obtained by the time integration unit and the relationship data; and a variation calculation unit that calculates the variation in the processing amount within the surface of the workpiece based on the change over time in the output value of the measurement unit.

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