End point detection device, etching control system, end point detection method, and end point detection program

Abstract

To accurately perform etching treatment of a multilayer film by accurately acquiring an end point.SOLUTION: An end point detection device for detecting an end point in etching treatment of a multilayer film, comprises: a measurement unit for measuring a physical quantity varying in the etching treatment; an end point detection unit for detecting an end point of an end point detection target film on the basis of a measured value acquired by the measurement unit and using a predetermined detection algorithm; and an algorithm change unit that on the basis of a measured value acquired by the measurement unit in performing etching treatment on another film whose type is the same as that of the target film in a multilayer film which is the same as the target film under the etching treatment, changes the detection algorithm for the film under the etching treatment.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an endpoint detection device, an etching control system, an endpoint detection method, and an endpoint detection program.

Background Art

[0002] In the semiconductor manufacturing process, when etching a semiconductor wafer, a technique for stopping the etching process at a desired depth has become more important. This is because the surface roughness of the film after the etching process greatly affects the characteristics of the semiconductor device. And a technique for detecting the endpoint in the etching process in real time is required to improve the yield.

[0003] In particular, in a wafer having a multilayer film (hereinafter, a multilayer film wafer), the same wafer is etched deeper, and the deeper the depth and the smaller the aperture ratio, the more difficult it is to detect the endpoint.

[0004] Here, as in Patent Document 1, a method of determining the endpoint of the etching process by measuring the time change of the plasma emission intensity from the etching process chamber by emission spectroscopy is considered.

[0005] However, there are non-plasma processes that cannot be measured by emission spectroscopy, and a decrease in emission intensity caused by a decrease in the aperture ratio or a decrease in the etching rate accompanying an increase in the etching depth. In some cases, the endpoint cannot be accurately obtained by emission spectroscopy.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to perform the etching process of a multilayer film with high precision by accurately obtaining an endpoint.

Means for Solving the Problems

[0008] That is, an endpoint detection device according to the present invention is an endpoint detection device for detecting an endpoint in an etching process of a multilayer film, including a measurement unit that measures a physical quantity that changes with the etching process, and an endpoint detection unit that detects an endpoint in a target film by a predetermined detection algorithm based on a measurement value obtained by the measurement unit, and an algorithm change unit that changes the detection algorithm in the film being etched based on a measurement value obtained by the measurement unit when another film of the same type as the target film in the same multilayer film as the target film being etched was previously etched.

[0009] With such an endpoint detection device, based on the measurement value obtained by the measurement unit when another film of the same type as the target film in the same multilayer film as the target film being etched was previously etched, the detection algorithm for the endpoint in the film being etched in the multilayer film is changed. Therefore, the endpoint in the film being etched can be accurately obtained. As a result, the etching process of the multilayer film can be performed with high precision.

[0010] As a specific embodiment of the algorithm change unit, it is desirable that the algorithm change unit changes the detection algorithm for the endpoint in the film being etched based on two or more past measurement values obtained by the measurement unit when another film of the same type as the target film in the same multilayer film as the target film being etched was previously etched. With this configuration, by using measurement values for the past two or more times, it is possible to change the endpoint detection algorithm in the film during the etching process to an optimal one.

[0011] As a specific embodiment of the algorithm change unit, it is desirable that the algorithm change unit changes the detection threshold value of the endpoint in the film during the etching process.

[0012] As a specific embodiment of the endpoint detection unit, it is desirable that the endpoint detection unit calculates the transition time between the transition start point and the transition end point when the film being etched transitions from the film during the etching process to the next film.

[0013] The endpoint detection device according to the present invention further includes a data storage unit that stores relationship data indicating the relationship between the transition time between the transition start point and the transition end point and the slope of the measurement value between them in the measurement value obtained by the measurement unit when another film of the same type as the target film in the same multilayer film as the target film during the etching process was previously etched, and it is desirable that the endpoint detection unit calculates the transition time when the film during the etching process transitions to the next film based on the relationship data and the slope immediately after the transition start point in the film during the etching process. With this configuration, even when the film thickness of the film during the etching process is different from that of the same type of film previously etched, it is possible to accurately obtain the transition time when the film during the etching process transitions to the next film.

[0014] It is desirable that the endpoint detection device according to the present invention further includes a display control unit that displays the time-series change of the measurement value obtained by the measurement unit on a display. With this configuration, by displaying the time-series change of the measurement value on a display, it can be used as a reference when the user changes the etching recipe.

[0015] As a specific embodiment of the measurement unit, it is desirable that the measurement unit measures the reaction product generated by the etching process by absorbance measurement. For example, by measuring the reaction product generated by the etching process by absorbance spectroscopy, the end point can be detected even in a non-plasma process that cannot be measured by emission spectroscopy as in the prior art.

[0016] Further, the etching control system according to the present invention includes an etching control device that controls an etching processing apparatus for etching a multilayer film, and the endpoint detection device described above. When a transition start point indicating that the transition from the film being etched to the next film has started is detected by the endpoint detection device during the etching process, it is desirable that the etching control device changes the etching recipe for the film being etched in the multilayer film. With this etching control system, after a transition start point indicating that the film being etched has started to transition from the film being etched to the next film is detected, the etching recipe for the film being etched is changed, so that an optimal recipe can be obtained and the etching process can be performed with high precision.

[0017] It is desirable that the etching control device changes the etching rate of the film being etched in the multilayer film. Here, changing the etching rate includes, for example, adjusting the flow rate of the reactive gas introduced into the process chamber for the etching process, changing the plasma power generated in the process chamber, or changing the temperature (reaction temperature) of the object to be etched (e.g., a wafer).

[0018] Furthermore, the endpoint detection method according to the present invention is an endpoint detection method for detecting an endpoint in the etching process of a multilayer film, which measures a physical quantity that changes with the etching process by a measurement unit, and based on the measurement value obtained by the measurement unit, detects an endpoint in a target film for detecting an endpoint by a predetermined detection algorithm, and it is desirable to change the detection algorithm in the film during the etching process based on the measurement value obtained by the measurement unit when another film of the same type as the target film in the same multilayer film as the target film during the etching process was previously etched.

[0019] Moreover, the endpoint detection program according to the present invention is a program used in an endpoint detection device for detecting an endpoint in the etching process of a multilayer film, which has a function as a reception unit that receives measurement value data from a measurement unit that measures changes accompanying the etching process, a function as an endpoint detection unit that detects an endpoint in a target film for detecting an endpoint by a predetermined detection algorithm based on the measurement value obtained by the measurement unit, and a function as an algorithm change unit that changes the detection algorithm in the film during the etching process based on the measurement value obtained by the measurement unit when another film having the same composition as the target film in the same multilayer film as the target film during the etching process was previously etched, and is characterized by causing a computer to have these functions.

[0020] Note that the endpoint detection program may be electronically distributed or may be recorded on a program recording medium such as a CD, DVD, or flash memory. Also, the endpoint detection program may be incorporated into the mother board of the device body.

Advantages of the Invention

[0021] Thus, according to the present invention, by accurately obtaining the endpoint, the etching process of the multilayer film can be performed with high precision.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0023] <An Embodiment of the Present Invention> Hereinafter, an embodiment of an etching control system incorporating an endpoint detection device according to the present invention will be described with reference to the drawings. Note that, for the sake of clarity, all the figures shown below are schematically drawn with appropriate omissions or exaggerations. For the same components, the same reference numerals are given and the description is omitted as appropriate.

[0024] <Device Configuration> As shown in FIG. 1, the etching control system 100 of the present embodiment controls an etching processing apparatus 200 for performing an etching process such as plasma etching. The object W of the etching process here is, as shown in FIG. 2, for example, a silicon substrate having a multilayer film structure formed on its main surface. As the multilayer film structure, a structure in which two types of films (here, SiO film and SiN film) are alternately formed can be considered. Note that the multilayer film structure may be a structure in which three or more types of films are periodically formed.

[0025] In addition, the etching processing apparatus 200 includes a process chamber 201 in which etching processing is performed, a plasma generation mechanism (not shown) that generates plasma P in the process chamber 201, and a gas introduction mechanism 202 that introduces a reactive gas into the process chamber 201. The gas introduction mechanism 202 is provided with a flow rate adjustment mechanism 202a (for example, a mass flow controller) that adjusts the flow rate of the reactive gas introduced into the process chamber 201.

[0026] Specifically, as shown in FIG. 1, the etching control system 100 includes an etching control device 2 that controls an etching processing apparatus 200 for etching a multilayer film, and an endpoint detection device 3 that detects an endpoint in the etching processing of the multilayer film.

[0027] <Etching control device 2> The etching control device 2 etches the multilayer film by controlling the etching processing apparatus 200.

[0028] Specifically, the etching control device 2 controls the etching processing apparatus 200 based on a recipe preset for each film in the multilayer film, and controls evacuation of the process chamber 201, plasma generation by the plasma generation mechanism, introduction of the reactive gas by the gas introduction mechanism 202, etc., to control the etching processing of the multilayer film. This etching control device 2 can control the etching rate by controlling the flow rate adjustment mechanism 202a of the gas introduction mechanism 202.

[0029] <Endpoint detection device 3> The endpoint detection device 3 detects an endpoint in the etching processing of the multilayer film, and also detects the transition from the currently etched film in the multilayer film to the next film.

[0030] Note that in the following embodiments, an endpoint is the end point of the transition time from the current film being etched to the next film. Note that the endpoint may be determined artificially by comparing the signal obtained from the measurement unit 31 described later with the etching processing result. For example, the start point of the transition period may be used as the endpoint, or the midpoint of the transition period may be used as the endpoint.

[0031] Specifically, the endpoint detection device 3 includes a measurement unit 31 that measures a physical quantity that changes with the etching process, and an endpoint detection unit 32 that changes the detection algorithm of the endpoint in the current film being etched in the multilayer film based on the measurement value obtained by the measurement unit 31 and detects the endpoint.

[0032] The measurement unit 31 of the present embodiment measures the reaction product (by-product) generated by the etching process by absorption spectroscopy. Specifically, the measurement unit 31 uses infrared laser absorption spectroscopy, and includes a laser light source 31a that irradiates an infrared laser into the process chamber 201 or the exhaust pipe 203 connected to the process chamber 201, a photodetector 31b that detects the infrared laser that has passed through the process chamber 201 or the exhaust pipe 203 connected to the process chamber 201, and an arithmetic unit 31c that calculates the concentration or partial pressure of the measurement target component using the light intensity signal of the photodetector 31b. Note that the measurement unit 31 of the present embodiment uses the infrared laser absorption modulation method (Japanese Patent No. 6886507), but other absorption spectroscopy methods may be used.

[0033] Here, the laser light source 31a is a semiconductor laser. Specifically, the laser light source is a quantum cascade laser (QCL), which is a type of semiconductor laser, and oscillates mid-infrared (2.5 to 25 μm) laser light. This laser light source 31a can modulate (change) the oscillation wavelength by a given current (or voltage). Note that as long as the oscillation wavelength is variable, other types of lasers may be used, and the temperature may be changed or the like to change the oscillation wavelength.

[0034] Further, the photodetector 31b may be a thermal photodetector such as a thermopile, or may be a photodetector using a quantum photoelectric element such as HgCdTe, InGaAs, InAsSb, or PbSe.

[0035] The arithmetic unit 31c calculates the absorption signal (absorbance signal) of the gas from the light intensity signal output from the photodetector 31b, extracts the feature amount from the absorption signal, and thereby calculates the concentration or partial pressure of the component to be measured. The concentration or partial pressure of the component to be measured calculated by the arithmetic unit 31c is output as a measurement value to the endpoint detection unit 32 and the algorithm change unit 33. Note that the arithmetic unit 31c includes an analog electric circuit composed of a buffer, an amplifier, etc., a digital electric circuit composed of a CPU, a memory, etc., and an AD converter, a DA converter, etc. that mediate between these analog / digital electric circuits.

[0036] The endpoint detection unit 32 detects the endpoint of the target film for detecting the endpoint by a predetermined detection algorithm based on the measurement value obtained by the measurement unit 31, and also detects the transition from the film currently being etched in the multilayer film to the next film. Here, the endpoint detection unit 32 can detect the endpoint in the etching process of the multilayer film based on the measurement value itself obtained by the measurement unit 31 or other parameters obtained based on the measurement value.

[0037] Further, the algorithm change unit 33 changes the detection algorithm for the film being etched currently based on the measurement values obtained by the measurement unit 31 when another film having the same composition as the target film in the same multilayer film that was etched previously is etched. Here, the algorithm change unit 33 can change the detection algorithm based on the measurement values themselves obtained by the measurement unit 31, or parameters related to the endpoint obtained based on the measurement values (for example, transition time, slope of the measurement value, value obtained by differentiating the measurement value once, value obtained by differentiating the measurement value twice, etc.). Note that the same type of film refers to a film having the same film constituent components, crystal structure, etc.

[0038] Here, the "measurement values obtained by the measurement unit 31 when etched previously" are the measurement values obtained by the measurement unit 31 when another film of the same type as the target film being etched currently is etched previously within the multilayer film being etched currently. For example, when the film being etched currently in the multilayer film is, for example, the 5th layer SiO film, the measurement values are those obtained by the measurement unit 31 when the 1st layer or 3rd layer SiO film, which is a layer above the 5th layer in the multilayer film, is etched previously.

[0039] Also, as shown in FIG. 3, the detection method of the endpoint detection unit 32 of the present embodiment is performed by detecting the transition start point (first change point X1) and the transition end point (second change point X2) of the transition from the film being etched currently to the next film in the time-series graph of the measurement values.

[0040] Specifically, as shown in FIG. 3, the endpoint detection unit 32 detects the transition start point (first change point X1) using two regression lines L1 and L2, and detects the transition end point (second change point X2) using two regression lines L3 and L4. Here, by the endpoint detection unit 32 detecting the transition end point (second change point X2), it can be determined that the etching process of the film being etched currently is completed.

[0041] Then, changing the detection algorithm of the endpoint detection unit 32 by the algorithm change unit 33 includes changing the parameters used in the above-described detection method, and includes changing the period during which the endpoint is not subjected to regression analysis, the period during which the endpoint is subjected to regression analysis, the confidence interval of the regression line, the period during which endpoint determination is not performed, the threshold value of the measurement value, the detection threshold value of the endpoint, or the filter frequency, etc.

[0042] <Calculation method 1 of transition time> The endpoint detection unit 32 calculates the transition time from the currently etched film to the next film based on the measurement values of two or more previous times obtained by the measurement unit 31 when etching another film of the same type as the currently etched film. Hereinafter, although the film being etched is a SiO film, the same applies when the film being etched is a SiN film.

[0043] For example, as shown in FIG. 4, in a multilayer film, when the currently etched film is the fifth-layer SiO film, based on the measurement value obtained by the measurement unit 31 when etching the first-layer SiO film and the measurement value obtained by the measurement unit 31 when etching the third-layer SiO film, the transition time of the currently etched fifth-layer SiO film is calculated. Note that the transition time is the elapsed time from the transition start point (here, the transition start point from the fifth layer to the sixth layer) to the transition end point (here, the transition end point from the fifth layer to the sixth layer).

[0044] Specifically, the transition time of the fifth-layer SiO film can be calculated by obtaining the ratio of the transition time of the first-layer SiO film to the transition time of the third-layer SiO film. In addition to using the measurement value itself obtained by the measurement unit 31, a value obtained by differentiating the measurement value once can be used, or a value obtained by differentiating the measurement value twice can be used.

[0045] For example, when the transition time of the first-layer SiO is T1 and the transition time of the third-layer SiO is T3 (= T1 × k (coefficient)), the transition time T5 of the fifth-layer SiO is T5 = T3 × k = T1 × k 2It can be obtained as such. Thereby, the transition time T5 of the fifth-layer SiO can be calculated, and the time to reach the endpoint can be predicted.

[0046] <Calculation method 2 of transition time> Also, the endpoint detection unit 32 calculates the transition time from the currently etched film to the next film based on the relationship between the transition time in the measurement values obtained by the measurement unit 31 when etching a film of the same type as the currently etched film previously and the slope of the measurement values between them, and the slope of the measurement value immediately after the transition start point in the currently etched film.

[0047] Here, the relationship data indicating the relationship between the transition time between the transition start point and the transition end point in the measurement values obtained by the measurement unit when etching a film of the same type as the currently etched film previously and the slope of the measurement values between them is stored in the data storage unit D1 (see FIG. 1). The relationship between the transition time and the slope of the measurement value in the present embodiment is the ratio (α / T) of the slope (α) of the measurement value at the transition time (T) to the transition time (T). Also, this relationship data may be calculated by the endpoint detection unit 32 or may be calculated by an external calculation device.

[0048] For example, as shown in FIG. 4, when the endpoint detection unit 32 detects the slope (α3) immediately after the transition start point of the third-layer SiO film using the ratio (α1 / T1) of the slope (α1) of the transition time T1 of the first-layer SiO film to the transition time T1, the transition time T3 of the third-layer SiO film can be obtained as T3 = (α3 / α1) × T1 from the detected slope (α3) of the transition time T3 of the third-layer SiO film and the ratio (α1 / T1) of the first-layer SiO. Also, when the endpoint detection unit 32 detects the slope (α5) immediately after the transition start point of the fifth-layer SiO film using the ratio (α3 / T3) of the slope (α3) of the transition time T3 of the third-layer SiO film to the transition time T3, the transition time T5 of the fifth-layer SiO film can be obtained as T5 = (α5 / α3) × T3 from the detected slope (α5) of the transition time T5 of the fifth-layer SiO film and the ratio (α3 / T3) of the third-layer SiO.

[0049] Further, the endpoint detection device 3 may include a data storage unit D1 that stores the time-series data of the measurement values of each layer obtained by the measurement unit 31, and a display control unit 34 that displays the time-series data of the measurement values of each layer on the display 4. This display control unit 34 can display not only the time-series data of the measurement values of each layer, but also the data of the first derivative or the second derivative thereof, and can also display the transition time calculated by the endpoint detection unit 32 and the like.

[0050] Note that the above-described endpoint detection unit 32, algorithm change unit 33, display control unit 34, and data storage unit D1 are composed of, for example, a so-called computer including a CPU, a memory, an A / D·D / A converter, and input / output means. When the endpoint detection program stored in the memory is executed and various devices cooperate, functions as the endpoint detection unit 32, algorithm change unit 33, display control unit 34, data storage unit D1, etc. are exhibited.

[0051] Then, when the etching control device 2 detects a transition start point indicating that the transition from the current film being etched to the next film has started by the endpoint detection device 3, the etching recipe for the current film being etched can be changed.

[0052] Specifically, it is conceivable to change the etching rate of the film currently being etched in the etching control apparatus 2. At this time, the etching control apparatus 2 controls the etching rate by controlling the flow rate adjustment mechanism 202a of the gas introduction mechanism 202 or the like. For example, it is conceivable that the etching control apparatus 2 controls the flow rate adjustment mechanism 202a to reduce the flow rate of the reactive gas, thereby reducing the etching rate. In addition, it is conceivable to reduce the etching rate by changing the plasma power generated in the process chamber. Further, it is conceivable to reduce the etching rate by changing the temperature (reaction temperature) of the object to be etched (e.g., wafer) in the etching process. Further, as the transition time elapses, the flow rate of the reactive gas or the like may be continuously or stepwise changed. Then, when the transition time of the film currently being processed has elapsed, the etching control apparatus 2 can stop the etching process or change to a recipe corresponding to the next film.

[0053] <Effects of this Embodiment> As described above, according to the etching control system 100 in this embodiment, based on the measurement value obtained by the measurement unit 31 when another film of the same type as the film currently being etched was previously etched, the detection algorithm for the endpoint of the film currently being etched in the multilayer film is changed. Therefore, the endpoint of the film currently being etched can be accurately obtained. As a result, the etching process of the multilayer film can be performed with high precision. Further, since the reaction product generated by the etching process is measured by absorption spectroscopy, the endpoint can be detected even in a process that generates a reaction product that cannot be measured by emission spectroscopy as in the prior art.

[0054] <Other Embodiments> For example, in the above-described embodiment, the endpoint detection device was incorporated into the etching control system, but it may also be configured not to be incorporated into the etching control system. In this case, the user may feedback data such as transition time obtained by the endpoint detection device to the etching control device.

[0055] Also, in the case where the thicknesses of a plurality of films of the same type in the multilayer film are different, if the relationship between those film thicknesses and the etching rate is known in advance, the transition time and the like measured by the endpoint detection unit 32 can also be corrected based on them.

[0056] Furthermore, although the above-described embodiment detects the endpoint in the etching process, it can also be applied to detecting the endpoint of chamber conditioning such as cleaning of the process chamber 201.

[0057] The measurement unit 31 in the above-described embodiment uses an absorption spectroscopy such as infrared laser absorption spectroscopy, but it may also use an optical measurement method such as emission spectroscopy or ICP emission spectroscopy. Also, the measurement unit 31 may use a mass spectrometry method such as quadrupole mass spectrometry. Also, as long as the measurement unit 31 measures a physical quantity that changes with the etching process, in addition to the absorption intensity, it may measure the emission amount or other physical quantities.

[0058] In addition, various modifications and combinations of embodiments may be made as long as they do not contravene the spirit of the present invention.

Explanation of Reference Numerals

[0059] 100 ··· Etching control system 2 ··· Etching control device 3 ··· Endpoint detection device 31 ··· Measurement unit 32 ··· Endpoint detection unit 33 ··· Algorithm change unit 34 ··· represents the control unit D1 ··· data storage unit 4 ··· display

Claims

1. An endpoint detection device for detecting an endpoint in an etching process of a multilayer film, comprising: a measurement unit that measures a physical quantity that changes with the etching process; an endpoint detection unit that detects an endpoint in a film to be detected by a predetermined detection algorithm based on a measurement value obtained by the measurement unit; an algorithm change unit that changes the detection algorithm in the film being etched based on measurement values obtained by the measurement unit when another film of the same type as the film being etched was previously etched in the same multilayer film as the film being etched.

2. The endpoint detection device according to claim 1, wherein the algorithm change unit changes a detection threshold value of the endpoint in the film being etched.

3. The endpoint detection device according to claim 1 or 2, wherein the endpoint detection unit calculates a transition time between a transition start point and a transition end point when the film being etched transitions from the film being etched to the next film.

4. The endpoint detection device according to any one of claims 1 to 3, wherein the algorithm change unit changes the detection algorithm of the endpoint in the film being etched based on two or more past measurement values obtained by the measurement unit when another film of the same type as the film being etched was previously etched in the same multilayer film as the film being etched.

5. further comprising a data storage unit that stores relationship data indicating a relationship between a transition time between a transition start point and a transition end point in the measurement values obtained by the measurement unit when another film of the same type as the film being etched was previously etched in the same multilayer film as the film being etched, and a slope of the measurement values therebetween; The endpoint detection device according to claim 4, wherein the endpoint detection unit calculates the transition time when the film being etched transitions to the next film based on the relationship data and a slope of the measurement value immediately after the transition start point in the film being etched.

6. The endpoint detection device according to any one of claims 1 to 5, further comprising a display control unit that displays a time-series change of the measurement value obtained by the measurement unit on a display.

7. The endpoint detection device according to any one of claims 1 to 6, wherein the measurement unit measures the reaction product generated by the etching process by absorbance measurement.

8. An etching control device that controls an etching processing device for etching a multilayer film, and an endpoint detection device according to any one of claims 1 to 7, wherein when a transition start point indicating that the film being etched by the endpoint detection device has started to transition from the film being etched to the next film is detected, the etching control device changes the etching recipe for the film being etched in the multilayer film. An etching control system.

9. The etching control system according to claim 8, wherein the etching control device changes the etching rate of the film being etched in the multilayer film.

10. An endpoint detection method for detecting an endpoint in the etching process of a multilayer film, measuring a physical quantity that changes with the etching process by a measurement unit, detecting an endpoint in the target film to be detected by a predetermined detection algorithm based on the measurement value obtained by the measurement unit, changing the detection algorithm for the film being etched based on the measurement value obtained by the measurement unit when previously etching another film of the same type as the target film in the same multilayer film as the target film being etched. An endpoint detection method.

11. A program used for an endpoint detection device for detecting an endpoint in the etching process of a multilayer film, a function as a reception unit that receives measurement value data from a measurement unit that measures changes associated with the etching process, a function as an endpoint detection unit that detects an endpoint in the target film to be detected by a predetermined detection algorithm based on the measurement value obtained by the measurement unit, and a function as an algorithm change unit that changes the detection algorithm for the film being etched based on the measurement value obtained by the measurement unit when previously etching another film of the same type as the target film in the same multilayer film as the target film being etched. An endpoint detection program that causes a computer to have.

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