JP2010060388A - Pattern shape inspection method and manufacturing method for semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern shape inspection method capable of accurately inspecting a pattern shape in an SWT (Side Wall Transfer) process, and to provide a manufacturing method for a semiconductor device with improved quality. <P>SOLUTION: The pattern shape detection method inspects the cross-sectional shape of a second pattern formed by a side wall covering a side wall of a first pattern cyclically formed on a substrate, and includes: a measurement step (S21) of acquiring measurement data including amplitude ratio spectra of reflected light which is diffracted and reflected incident light to the substrate having the second pattern formed thereon and phase difference spectra; and determination steps (S22 to S25) of determining the cross-sectional form of the second pattern by calculating a plurality of calculated data including calculated amplitude ratio spectra and phase difference spectra of a plurality of cross-sectional form models each having a different form parameter for determining the cross-sectional form of the side wall and determining a form parameter so that the calculated data optimally matches the measurement data of the second pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pattern shape inspection method and a semiconductor device manufacturing method, and more particularly to a pattern shape inspection method and a semiconductor device manufacturing method when a semiconductor device is manufactured using a double patterning technique including an SWT method.

  Conventionally, in a manufacturing process of a semiconductor device or the like, a fine circuit pattern or the like is formed by performing an etching process such as plasma etching on a substrate such as a semiconductor wafer. In such an etching process, an etching mask is formed by a photolithography process using a photoresist.

Here, the resolution in photolithography is expressed as k ₁ × λ / NA using a constant k ₁ determined by process conditions and an optical system, a wavelength λ of exposure light, and a numerical aperture NA of the lens. The numerical aperture NA is proportional to the refractive index n. Therefore, the resolution is reduced by shortening the wavelength of light used for exposure and increasing the refractive index of the optical system. An example of realizing miniaturization according to this principle is ArF immersion lithography.

  However, as the state-of-the-art design rule of semiconductor devices is further miniaturized from 45 nm to 32 nm, the photolithography that exposes a photoresist film using an optical system and develops the pattern to form a pattern only with the semiconductor device. It becomes impossible to follow the miniaturization. Accordingly, various new technologies have been developed that do not depend only on miniaturization of the photolithography technology. One of them is a so-called double patterning process (double patterning technology). In this double patterning technique, etching is performed in one pattern by performing two-stage patterning of a first mask pattern forming step and a second mask pattern forming step performed after the first mask pattern forming step. A finer interval is formed than when a mask is formed (see, for example, Patent Document 1).

Also, for example, an SWT (Side Wall Transfer) process that uses a SiO ₂ film, a Si ₃ N ₄ film, or the like as a sacrificial film and forms a mask on both side walls of one pattern, There is also known a method of patterning at a finer pitch than a photoresist pattern obtained by exposing and developing a resist film. In this method, an Si ₃ N ₄ film or the like is first formed on a photoresist pattern, and then etched back so that the Si ₃ N ₄ film remains only on the side wall portion that covers the side surface of the SiO ₂ film serving as the core. Thereafter, the SiO ₂ film at the core is removed by wet etching, and the lower layer is etched using the remaining Si ₃ N ₄ film as the side wall as a mask.

In the film forming technique for forming the side wall portion, it is required to form the film at a lower temperature because the film is formed on the photoresist pattern. As a technique for forming a film at such a low temperature, a method performed by a chemical vapor deposition method is known (see, for example, Patent Document 2).
JP 2007-027742 A JP 2006-179819 A

  However, when manufacturing a semiconductor device using the double patterning technique including the SWT process, there are the following problems.

  Since the thickness (width) of the sidewall in the SWT process is very thin (currently 20 to 30 nm), a film forming step for forming a material for forming the sidewall in the SWT process, and the side wall after that, In the etch-back process for etching back the material to be formed, great care is required in order to obtain a pattern having a substantially constant shape within the wafer surface or between the wafers. If the side wall bottom width, side wall height, and side wall side tilt angle from the top surface of the substrate are not formed as designed, the side wall shape is as designed. If the process proceeds to the next process, that is, the etching process in which etching is performed using the side wall as a hard mask without knowing that the shape is not the shape, a pattern having lines and spaces as originally designed is transferred to the film under the hard mask ( Will not be transferred). Even if a defect is determined in the inspection after the etching step, it is difficult to reprocess the wafer and perform the process again after proceeding to a later step.

  Furthermore, in the SWT process, the shape of the side wall is designed on the assumption that it is a symmetric shape. Therefore, the width of the bottom of the side wall that defines the shape of the side wall, the height of the side wall, and the inclination angle of the side wall of the side wall from the top surface of the substrate are as designed as the average value of the left and right side walls. If the shape of each asymmetric side wall is not formed according to the design, if the process proceeds to the next etching process without knowing that the shape of the asymmetric side wall is not the shape as designed, the original film is formed on the lower layer of the hard mask. Even if the pattern having the designed line and space is not transferred and a defect is determined in the inspection after the etching process, it is difficult to regenerate the wafer.

  The present invention has been made in view of the above points. In a manufacturing process for manufacturing a semiconductor device using a double patterning technique including an SWT process, a pattern is obtained by measuring the shape of a sidewall (side wall) with high accuracy. A method for manufacturing a semiconductor device capable of improving the quality of a manufactured semiconductor device and the productivity of a manufacturing process by providing a pattern shape inspection method capable of inspecting the shape and including the pattern shape inspection method It is to provide.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

  A pattern shape inspection method according to a first invention is a pattern shape inspection method for inspecting a cross-sectional shape of a second pattern comprising a side wall portion covering a side wall of a first pattern periodically formed on a substrate. Then, the incident light is incident on the substrate on which the second pattern is formed at a predetermined incident angle, and measurement data is obtained that includes the amplitude ratio spectrum and the phase difference spectrum of the reflected light that is diffracted and reflected by the incident light. Using a cross-sectional shape model that models the cross-sectional shape of the second pattern including a step and a shape parameter that determines the cross-sectional shape of the side wall, and corresponding to a plurality of cross-sectional shape models having different shape parameters, The calculated amplitude ratio spectrum and phase difference spectrum of the reflected light in which the incident light is diffracted and reflected into a model pattern in which the cross-sectional shape model is periodically and continuously formed Calculating a plurality of calculation data, determining the model pattern so that the calculation data most closely matches the measurement data of the second pattern, and determining the shape parameter corresponding to the model pattern And a determining step for determining a cross-sectional shape of the second pattern.

  According to a second invention, in the pattern shape inspection method according to the first invention, after the determining step, the magnitude relationship between the determined shape parameter and a predetermined upper limit reference value and a lower limit reference value of the shape parameter is determined. And a determination step of outputting an alarm when the shape parameter is larger than the upper limit reference value or smaller than the lower limit reference value.

  According to a third aspect of the present invention, in the pattern shape inspection method according to the first or second aspect, the shape parameter is a width or a height of the side wall portion or an inclination angle from the upper surface of the substrate, respectively. To do.

  According to a fourth aspect of the present invention, in the pattern shape inspection method according to any one of the first to third aspects, the determining step calculates the plurality of calculation data in advance, and calculates the plurality of calculation data calculated in advance. Using the stored database, the model pattern is determined so that the calculation data stored in the database most closely matches the measurement data of the second pattern.

  According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an organic film on an etching target layer on a substrate; and processing the organic film by photolithography to form a first pattern having a predetermined pitch. Forming a first pattern; forming a silicon oxide film on the layer to be etched so as to cover a side surface of the first pattern; and forming the silicon oxide film on the first pattern. An etching step of etching so as to remain as a sidewall portion, a second pattern forming step of forming a second pattern composed of the sidewall portion remaining by removing the organic film of the first pattern, And a pattern shape inspection step for performing the pattern shape inspection method according to any one of the first to fourth aspects.

  A sixth invention is characterized in that, in the semiconductor device manufacturing method according to the fifth invention, the organic film is a BARC film or a photoresist film.

  According to a seventh aspect of the present invention, in the method for manufacturing a semiconductor device according to the fifth or sixth aspect, the pattern shape inspection method is performed between the etching step and the second pattern formation step.

  A manufacturing method of a semiconductor device according to an eighth invention includes a first manufacturing process for manufacturing a semiconductor device on a first substrate using the semiconductor device manufacturing method according to the seventh invention, and a first manufacturing process. And a second manufacturing step of manufacturing the semiconductor device on the second substrate using the semiconductor device manufacturing method according to the seventh invention, wherein the first manufacturing Determining the magnitude relationship between the shape parameter determined in the pattern shape inspection step included in the process and a predetermined lower limit value of the shape parameter, and when the shape parameter is smaller than the lower limit value, The etching time in the etching process included in the manufacturing process is changed to be shorter than the etching time in the etching process included in the first manufacturing process, and the second manufacturing process is performed. The features.

  According to a ninth aspect of the present invention, there is provided a pattern shape inspection method, comprising: a first side wall portion covering a side wall on one side of a first pattern periodically formed on a substrate; and the first side of the first pattern. A pattern shape inspection method for inspecting a cross-sectional shape of a second pattern including a second side wall portion covering a side wall opposite to the side, and having a predetermined incidence on the substrate on which the second pattern is formed A measurement step of entering incident light at an angle and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected; and a first step of determining a cross-sectional shape of the first side wall portion A cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern including the shape parameter of the second pattern and the second shape parameter corresponding to the first shape parameter and determining the cross-sectional shape of the second side wall portion And the first shape Corresponding to a plurality of cross-sectional shape models having different parameters or the second shape parameter, the reflected light in which the incident light is diffracted and reflected into a model pattern in which the cross-sectional shape models are periodically continuous. Calculating a plurality of calculation data composed of a calculated amplitude ratio spectrum and phase difference spectrum, determining the model pattern so that the calculation data most closely matches the measurement data of the second pattern, Determining a cross-sectional shape of the second pattern by determining the corresponding first shape parameter and the second shape parameter.

  According to a tenth aspect of the present invention, in the pattern shape inspection method according to the ninth aspect, after the determining step, a dimensional difference between the determined first shape parameter and the second shape parameter, and a predetermined reference A determination step of determining a magnitude relationship with the value and outputting an alarm when the dimensional difference is greater than the reference value.

  An eleventh invention is the pattern shape inspection method according to the ninth or tenth invention, wherein the first shape parameter and the second shape parameter are the first side wall portion and the second side wall portion, respectively. The width, the height, or the inclination angle from the upper surface of the substrate.

  A twelfth aspect of the invention is the pattern shape inspection method according to any one of the ninth to eleventh aspects of the invention, wherein the determining step calculates the plurality of calculation data in advance, and calculates the plurality of calculation data calculated in advance. Using the stored database, the model pattern is determined so that the calculation data stored in the database most closely matches the measurement data of the second pattern.

  According to a thirteenth aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: forming an organic film on an etching target layer on a substrate; and processing the organic film by photolithography to form a first pattern having a predetermined pitch. Forming a first pattern; forming a silicon oxide film on the layer to be etched so as to cover a side surface of the first pattern; and forming the silicon oxide film on the first pattern. An etching step of etching so as to remain as a sidewall portion, a second pattern forming step of forming a second pattern composed of the sidewall portion remaining by removing the organic film of the first pattern, And a pattern shape inspection step for performing the pattern shape inspection method according to any one of the ninth to twelfth inventions.

  A fourteenth invention is characterized in that, in the semiconductor device manufacturing method according to the thirteenth invention, the organic film is a BARC film or a photoresist film.

  According to a fifteenth aspect of the invention, in the semiconductor device manufacturing method according to the thirteenth or fourteenth aspect, the pattern shape inspection step is performed between the etching step and the second pattern formation step.

  A pattern shape inspection method according to a sixteenth aspect of the present invention is a pattern shape inspection method for inspecting a cross-sectional shape of a silicon oxide film covering a first pattern periodically formed on a substrate, wherein the silicon oxide film is A measurement step of entering incident light at a predetermined incident angle on the formed substrate and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected; and Using a cross-sectional shape model that models the cross-sectional shape of the silicon oxide film including the thickness, each of the cross-sectional shape models is configured periodically and continuously corresponding to a plurality of cross-sectional shape models having different thicknesses. A plurality of calculation data consisting of the calculated amplitude ratio spectrum and phase difference spectrum of the reflected light from which the incident light is diffracted and reflected by the model pattern; Determining the model pattern so as to best match the measurement data of the silicon oxide film, and determining the cross-sectional shape of the silicon oxide film by determining the thickness corresponding to the model pattern; It is characterized by including.

  According to a seventeenth aspect, in the pattern shape inspection method according to the sixteenth aspect, after the determining step, a magnitude relationship between the determined thickness and a predetermined upper limit reference value and lower limit reference value of the thickness is determined. And a determination step of outputting an alarm when the thickness is larger than the upper limit reference value or smaller than the lower limit reference value.

  A pattern shape inspection method according to an eighteenth aspect of the invention is a pattern shape inspection method for inspecting a cross-sectional shape of a silicon oxide film covering a first pattern periodically formed on a substrate, wherein the silicon oxide film is A measurement step of making incident light incident on the formed substrate at a predetermined incident angle and obtaining measurement data comprising an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected; and the first pattern A first thickness of the silicon oxide film covering a side wall of the first pattern, and a second thickness of the silicon oxide film covering a side wall of the first pattern opposite to the one side. Using a cross-sectional shape model that models the cross-sectional shape of the silicon oxide film, each of the cross-sectional shape models has a period corresponding to a plurality of cross-sectional shape models having different first thicknesses or second thicknesses. A plurality of calculation data consisting of a calculated amplitude ratio spectrum and a phase difference spectrum of reflected light in which the incident light is diffracted and reflected by the model pattern configured in succession, and the calculation data of the silicon oxide film The cross-sectional shape of the silicon oxide film is determined by determining the model pattern so as to most closely match the measurement data, and determining the first thickness and the second thickness corresponding to the model pattern. And a determining step.

  According to a nineteenth aspect, in the pattern shape inspection method according to the eighteenth aspect, after the determining step, a dimensional difference between the determined first thickness and the second thickness, a predetermined reference value, and And a determination step of outputting an alarm when the dimensional difference is larger than the reference value.

  According to a twentieth aspect of the invention, in the pattern shape inspection method according to any one of the sixteenth to nineteenth aspects, the determining step calculates the plurality of calculation data in advance, and calculates the plurality of calculation data calculated in advance. Using the stored database, the model pattern is determined so that the calculation data stored in the database most closely matches the measurement data of the second pattern.

  According to a twenty-first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an organic film on an etching target layer on a substrate; and processing the organic film by photolithography to form a first pattern having a predetermined pitch. A first pattern forming step to be formed; a film forming step for forming a silicon oxide film on the etching target layer so as to cover a side surface of the first pattern; A pattern shape inspection step of performing the pattern shape inspection method according to any one of the inventions 20; an etching step of etching so that the silicon oxide film remains as a sidewall portion of the first pattern; And a second pattern forming step of forming a second pattern constituted by the side wall portion remaining by removing the organic film.

  According to a twenty-second aspect of the invention, in the method of manufacturing a semiconductor device according to the twenty-first aspect, the organic film is a BARC film or a photoresist film.

  According to the present invention, when manufacturing a semiconductor device using a double patterning technique including an SWT process, the shape of the sidewall (side wall) can be measured with high accuracy. Productivity of the manufacturing process can be improved.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
A semiconductor device manufacturing method and a pattern shape inspection method according to the first embodiment of the present invention will be described with reference to FIGS.

  First, a method for manufacturing a semiconductor device according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a flowchart for explaining the procedure of each step of the semiconductor device manufacturing method according to the present embodiment. FIG. 2 is a diagram for explaining a process of the method of manufacturing a semiconductor device according to the present embodiment, and is a cross-sectional view schematically showing the structure of the semiconductor device in each process. The structure of the semiconductor device after steps S11 to S17 and S19 of FIG. 1 are performed is as shown in FIGS. 2A (a) to 2C (g) and 2C (h). It corresponds to the structure shown in each sectional view.

  As shown in FIG. 1, the method for manufacturing a semiconductor device according to the present embodiment includes a first pattern forming step, a film forming step, an etching step, a second pattern forming step, a pattern shape inspection step, Etching the layer to be etched. The first pattern forming step includes steps S11 to S14, the film forming step includes step S15, the etching step includes step S16, and the second pattern forming step includes step S17. The pattern shape inspection process includes a process of step S18, and the process of etching the etching target layer includes a process of step S19. That is, the method for manufacturing a semiconductor device according to the present embodiment is characterized in that a pattern shape inspection step is performed after the second pattern formation step.

  First, a first pattern forming process including the processes of steps S11 to S14 is performed.

  Step S11 is a process of forming an organic film on the layer to be etched on the substrate. FIG. 2A (a) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S11 is performed.

  In step S11, as shown in FIG. 2A (a), an etching target layer 12 and an organic film 13 are formed on the substrate 11 in order from the bottom. The to-be-etched layer 12 functions as a mask when performing various subsequent processing steps by forming a pattern. The organic film 13 is formed with a pattern and functions as a mask for forming the pattern of the etched layer 12. Moreover, the organic film 13 may have a function as an antireflection film (BARC: Bottom Anti-Reflecting Coating) when performing photolithography of the photoresist film 14 formed thereon.

  The material of the layer to be etched 12 is not particularly limited, and for example, amorphous silicon or polysilicon can be used. Moreover, the thickness of the to-be-etched layer 12 is not specifically limited, For example, it can be 20-200 nm.

  The material of the organic film 13 is not particularly limited. For example, amorphous carbon formed by chemical vapor deposition (CVD), polyphenol formed by spin-on, photoresist such as i-line resist, and the like. A wide range of organic materials including can be used. Moreover, the thickness of the organic film 13 is not specifically limited, For example, it can be 150-300 nm.

  Step S12 is a step of forming a photoresist film 14 and exposing and developing the formed photoresist film 14 to form a resist pattern 14a made of the photoresist film 14. As a result, as shown in FIG. 2A (b), a resist pattern 14a made of the photoresist film 14 is formed. The resist pattern 14 a functions as a mask in the step of etching the organic film 13.

  For example, an ArF resist can be used as the material of the photoresist film 14. Further, the thickness of the photoresist film 14 is not particularly limited, and can be, for example, 50 to 200 nm. The line width L4 and the space width S4 of the resist pattern 14a are not particularly limited, Both may be 60 nm, for example.

  Step S13 is a step of trimming the photoresist film 14 forming the resist pattern 14a to form a resist pattern 14b made of the photoresist film 14. FIG. 2A (c) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S13 is performed.

  The trimming method is not particularly limited, and is performed using plasma of oxygen, nitrogen, hydrogen, ammonia or the like, for example. Further, as shown in FIGS. 2A (b) and 2A (c), the line width L1 of the trimmed resist pattern 14b is narrower than the line width L4 of the resist pattern 14a before trimming. The magnitude relationship between the line width L1 and space width S1 of the resist pattern 14b and the line width L4 and space width S4 of the resist pattern 14a is L1 <L4, S1> S4. The values of L1 and S1 are not particularly limited. For example, L1 can be set to 30 nm and S1 can be set to 90 nm.

  Step S <b> 14 is a first pattern forming step of forming the first pattern 21 made of the organic film 13 by etching the organic film 13 using the resist pattern 14 b as a mask. FIG. 2B (d) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S14 is performed.

After the trimming, the organic film 13 is etched using the resist pattern 14b made of the photoresist film 14 having the line width L4 as a mask to form a pattern having the line width L1 made of the organic film 13. For example, when the organic film 13 is composed of an SOG film (or a composite film of an LTO film and a BARC), for example, CF ₄ , C ₄ F ₈ , CHF ₃ , CH ₃ F, CH It can be performed using a CF gas such as ₂ F ₂ and a mixed gas such as Ar gas, or a gas obtained by adding oxygen to the mixed gas as necessary.

Next, a film forming process including the process of step S15 is performed. Step S15 is a film forming step of forming a SiO ₂ film 15 on the first substrate pattern 21 is formed 11. FIG. 2B (e) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S15 is performed.

The SiO ₂ film corresponds to the silicon oxide film in the present invention. In the following, instead of the SiO ₂ film, a film of another composition including a SiO _x film and containing silicon and oxygen as main components may be used. A silicon oxynitride film (SiON film) can also be used.

The SiO ₂ film forming process is performed in a state where the organic film 13 remains as the first pattern 21, but the organic film 13 is generally weak at a high temperature, and thus is formed at a low temperature (for example, about 300 ° C. or less). It is preferable. The film forming method is not particularly limited as long as the film can be formed at such a low temperature. In the present embodiment, molecular layer deposition (hereinafter referred to as MLD) at low temperature, that is, low-temperature MLD is used. Can be done by. As a result, as shown in FIG. 2B (e), the SiO ₂ film 15 is formed on the entire surface of the substrate including the place where the first pattern 21 is formed and the place where the first pattern 21 is not formed. The SiO ₂ film 15 is formed on the side surfaces of the first pattern 21 so as to cover the side surfaces of the first pattern 21. When the thickness of the SiO ₂ film 15 at this time is D, the width of the SiO ₂ film 15 covering the side surfaces of the first pattern 21 also becomes D. The thickness D of the SiO ₂ film 15 is not particularly limited, and can be, for example, 30 nm.

  Here, the film formation process by low temperature MLD is demonstrated.

  In low-temperature MLD, a process of supplying a raw material gas containing silicon into a processing container and adsorbing the silicon raw material on the substrate and a process of supplying a gas containing oxygen into the processing container and oxidizing the silicon raw material are alternately performed. Repeat.

  Specifically, in the step of adsorbing the source gas containing silicon on the substrate, the source silane gas containing silicon is a mesh silane gas having two amino groups in one molecule, for example, binary butylaminosilane (hereinafter, BTBAS) is supplied into the processing container through a silicon source gas supply nozzle for a predetermined time (T1). Thereby, BTBAS is adsorbed on the substrate. The time of T1 can be set to 1 to 60 seconds, for example. The flow rate of the source gas containing silicon can be 10 to 500 mL / min (sccm). Moreover, the pressure in a processing container can be 13.3-665Pa.

Next, in the step of supplying a gas containing oxygen into the processing container and oxidizing the silicon material, as the gas containing oxygen, for example, O ₂ gas converted into plasma by a plasma generation mechanism equipped with a high-frequency power source is used. A predetermined time (T2) is supplied into the processing container through the supply nozzle. Accordingly, BTBAS adsorbed on the substrate is oxidized, SiO ₂ film 15 is formed. The time T2 can be set to, for example, 5 to 300 seconds. The flow rate of the gas containing oxygen can be set to 100 to 20000 mL / min (sccm). The frequency of the high frequency power supply can be 13.56 MHz, and the power of the high frequency power supply can be 5 to 1000 W. Moreover, the pressure in a processing container can be 13.3-665Pa.

In addition, when switching between the above-described process of adsorbing the source gas containing silicon on the substrate and the process of supplying the gas containing oxygen into the processing container and oxidizing the silicon material, immediately before each process, In order to remove the residual gas in this step, a step of supplying a purge gas made of an inert gas such as N ₂ gas into the processing vessel while evacuating the inside of the processing vessel can be performed for a predetermined time (T3). . The time T3 can be set to 1 to 60 sec, for example. The flow rate of the purge gas can be 50 to 5000 mL / min (sccm). Note that this step is not limited as long as the gas remaining in the processing container can be removed, and evacuation can be continuously performed in a state where supply of all gases is stopped without supplying purge gas.

  BTBAS is an aminosilane gas having two amino groups in one molecule used as a source gas containing silicon. As such aminosilane gas, bisdiethylaminosilane (BDEAS), bisdimethylaminosilane (BDMAS), diisopropylaminosilane (DIPAS), and bisethylmethylaminosilane (BEMAS) can be used in addition to the above-described BTBAS. Furthermore, an aminosilane gas having 3 or more amino groups in one molecule can be used as the silicon source gas, and an aminosilane gas having one amino group in one molecule can also be used.

On the other hand, as gas containing oxygen, in addition to O ₂ gas, NO gas, N ₂ O gas, H ₂ O gas, and O ₃ gas can be used, and these are converted into plasma by a high frequency electric field and used as an oxidizing agent. Can do. By using such oxygen-containing gas plasma, the SiO ₂ film can be formed at 300 ° C. or lower, and further the gas flow rate of the oxygen-containing gas, the power of the high-frequency power source, and the pressure in the processing vessel can be adjusted. By adjusting, the SiO ₂ film can be formed at 100 ° C. or less or at room temperature.

Next, an etching process including the process of step S16 is performed. Step S16 is an etching process for the SiO ₂ film 15 is etched so as to leave only as a sidewall portion 15a of the first pattern 21. FIG. 2B (f) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S16 is performed.

As shown in FIG. 2B (f), the SiO ₂ film 15 is etched so that the SiO ₂ film 15 remains only as the side wall portion 15 a that covers the side surface of the first pattern 21. Etching of the SiO ₂ film 15 is not particularly limited. For example, a CF-based gas such as CF ₄ , C ₄ F ₈ , CHF ₃ , CH ₃ F, or CH ₂ F ₂ and a mixed gas such as Ar gas are used. Alternatively, this mixed gas can be used by using a gas to which oxygen is added as necessary. To etch so that only side wall portions 15a of the first pattern 21 made of SiO ₂ film 15 is left, the first pattern 21 and the third pattern 23 made of the side wall portion 15a is formed. Assuming that the line width of the third pattern 23 is L3 and the space width is S3, when the line width L1 of the first pattern 21 is 30 nm and the thickness D of the sidewall portion 15a is 30 nm, L3 = L1 + D × 2, S3 Since L1 + S1-L3, L3 can be set to 90 nm and S3 can be set to 30 nm.

The etching performed in the etching process in step S16 is also referred to as etching back because the surface of the SiO ₂ film 15 is retreated in the thickness direction by etching.

  Next, a second pattern forming process including step S17 is performed. Step S <b> 17 is a second pattern forming step of forming a second pattern composed of the side wall portions remaining by removing the organic film 13 of the first pattern 21. FIG. 2C (g) is a cross-sectional view illustrating the structure of the semiconductor device after the process of step S17 is performed.

Etching using plasma of oxygen, nitrogen, hydrogen, ammonia or the like is performed to remove the first pattern 21 made of the organic film 13. As a result, as shown in FIG. 2C (g), the first pattern 21 made of the organic film 13 is removed, leaving only the side wall portion 15a, the line width is D, and the space width is L1 and S3 appear alternately. A second pattern 22 having such a pattern is formed. In the present embodiment, by making the line width L1 of the first pattern 21 equal to the space width S3 of the third pattern 23, the space width becomes S2 equal to L1 and S3. Further, a line width equal to D is again set to L2. As described above, by setting L1 to 30 nm, S3 to 30 nm, and the thickness of the SiO ₂ film 15 (width D of the side wall 15a) to 30 nm, the second line width L2 is 30 nm and the space width S2 is 30 nm. A pattern can be formed.

  The pitch of the second pattern in the present invention means a repetition period equal to the line width L2 and the space width S2 of the second pattern, or the total length of the line width L2 and the space width S2.

  Next, a pattern shape inspection process including step S18 is performed. Step S18 is a pattern shape inspection process as described later, and is a pattern shape inspection process for inspecting whether the cross-sectional shape of the second pattern is appropriate.

  Next, a process of etching the layer to be etched including step S19 is performed.

In step S19, the etching target layer 12 which is the lower layer of the organic film 13 is etched using the second pattern 22 as a mask, and includes the etching target layer 12 having the SiO ₂ film 15 as an upper layer portion. This is a step of forming a fourth pattern 12 a having the same shape as the first pattern 21. FIG. 2C (h) is a cross-sectional view showing the structure of the semiconductor device after the process of step S19 is performed.

The layer to be etched 12 is etched using the second pattern 22 composed of the side wall portion 15a as a mask. For example, etching of the etching target layer 12 made of amorphous silicon or polysilicon is performed by, for example, Cl ₂ , Cl ₂ + HBr, Cl ₂ + O ₂ , CF ₄ + O ₂ , SF ₆ , Cl ₂ + N ₂ , Cl ₂ + HCl, HBr + Cl ₂ + SF _6. It can be performed using plasma such as gas. As a result, as shown in FIG. 2C (h), the fourth pattern 12a is formed.

  Here, the pattern shape inspection method for inspecting the pattern shape in the pattern shape step in the method of manufacturing the semiconductor device according to the present embodiment will be described with reference to FIGS. As described above, the pattern shape inspection step is a step including step S18 in FIG. 1, and is a step of performing a pattern shape inspection method for inspecting whether the cross-sectional shape of the second pattern is appropriate.

  FIG. 3 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present embodiment. FIG. 4 is a diagram for explaining the pattern shape inspection method according to the present embodiment, and is a diagram schematically showing the configuration of the reflectance measuring apparatus. FIG. 4A schematically shows the configuration of a reflectance measuring apparatus that makes incident light incident on a substrate at a predetermined incident angle and measures the amplitude ratio spectrum and phase difference spectrum of reflected light that is diffracted and reflected by the incident light. FIG. 4B is a diagram schematically showing the configuration of the reflectance measurement system including the reflectance measurement device. FIG. 5 is a diagram for explaining the pattern shape inspection method according to the present embodiment, and is a diagram showing a cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern. 5A is a diagram showing the entire cross-sectional shape model, FIG. 5B is an enlarged view of the periphery of the side wall portion, and FIG. 5C is a diagram in which the cross-sectional shape model is periodic. It is a figure which shows the model pattern comprised continuously. FIG. 6 is a diagram for explaining the pattern shape inspection method according to the present embodiment, and the calculation of the amplitude ratio spectrum and the phase difference spectrum of the reflected light in which the incident light is diffracted and reflected by the model pattern composed of the cross-sectional shape model. It is a graph which shows an example of data.

  The pattern shape inspection method according to the present embodiment uses an optical digital profilometry (ODP) system as pattern shape inspection means. ODP is similar to spectroscopic ellipsometry, etc., in which polarized light is incident and reflectance is measured to measure the amplitude ratio spectrum and phase difference spectrum of the reflected light, and the cross-sectional shape of the pattern shape. This is an analysis method for analyzing a cross-sectional shape by using a cross-sectional shape model including a shape parameter for modeling the above and using a reflectance calculation for calculating an amplitude ratio spectrum and a phase difference spectrum in calculating reflected light.

  In the method of measuring the reflectance, incident light that is white light including a broadband wavelength and is unpolarized or polarized is incident on the object to be measured, and the reflectance of the reflected light reflected is measured. The reflectance can be measured as an absolute value, or it can be measured as a relative value normalized by a predetermined reflectance reference value.

Among these, ellipsometry can be used as a method for measuring reflectance using polarized light. When incident light composed of ordinary white light that is not polarized light passes through the polarizer, the incident light becomes linearly polarized light having an electric field vector parallel to one axis of the polarizer. The linearly polarized light is composed of s-polarized light having p-polarized light having a parallel vector component and a vector component perpendicular to the incident plane that is a plane including incident light and reflected light. Ellipsometry is a measurement method that measures the change in polarization that occurs when each of p-polarized light and s-polarized light of incident light is reflected from a certain medium. A change in polarization is composed of two components: a change in amplitude (intensity) and a change in phase. Also, the change in polarization differs between a component of incident light having an electric field vector that oscillates in the incident plane and a component of incident light having an electric field vector that oscillates perpendicular to the incident plane. Ellipsometry uses two variables, the angle Δ, which is the phase change of the reflected light from which the incident light is reflected, and the angle Ψ, which is defined as the arctangent of the amplitude ratio of the incident light and the reflected light. The reflectance ratio ρ, which is the ratio of the reflectance of the p-polarized light and the s-polarized light expressed, is measured. That is, when the reflectance of p-polarized light is r _p and the reflectance of s-polarized light is r _s , the following equation holds.

一方、本実施の形態においては、被測定物である基板上には、周期的なパターンが形成されている。被測定物が周期的なパターンである場合、被測定物は回折格子とみなすことができ、反射光は回折格子によって回折された回折反射光となる。このような回折反射光が反射される場合の反射率の計算方法は、例えば、米国特許５８３５２２５号公報又は米国特許５７３９９０９号公報に記載されているような密結合波分析Rigorous Coupled Wave Analysis、以下ＲＣＷＡという）を用いることができる。ＲＣＷＡ計算を用いる場合は、例えば、以下のような第１から第４の４つのステップを行って回折反射率を計算することができる。第１のステップでは、矩形要素の集合体として近似する等の手法により回折格子の断面形状をモデル化する。第２のステップでは、回折格子の各要素の内部での電界、磁界、誘電率をフーリエ展開し、各層について離散化された微分方程式を構築する。第３のステップでは、各要素の間の境界において、電界及び磁界の境界条件を設定する。第４のステップでは、離散化された微分方程式を解くことによって、回折反射率を得る。

On the other hand, in the present embodiment, a periodic pattern is formed on the substrate that is the object to be measured. When the object to be measured has a periodic pattern, the object to be measured can be regarded as a diffraction grating, and the reflected light becomes diffracted reflected light diffracted by the diffraction grating. The calculation method of the reflectance when such diffracted reflected light is reflected is, for example, a tightly coupled wave analysis Rigorous Coupled Wave Analysis (hereinafter, RCWA) as described in US Pat. No. 5,835,225 or US Pat. No. 5,739,909. Can be used. When the RCWA calculation is used, for example, the diffraction reflectivity can be calculated by performing the following first to fourth steps. In the first step, the cross-sectional shape of the diffraction grating is modeled by a technique such as approximation as an assembly of rectangular elements. In the second step, an electric field, a magnetic field, and a dielectric constant inside each element of the diffraction grating are Fourier-expanded, and a differential equation discretized for each layer is constructed. In the third step, electric field and magnetic field boundary conditions are set at the boundary between the elements. In the fourth step, the diffraction reflectance is obtained by solving the discretized differential equation.

  Next, the procedure of the pattern shape inspection method according to the present embodiment will be described.

  The pattern shape inspection method according to the present embodiment includes a measurement step and a determination step, as shown in FIG. The measurement step includes step S21, and the determination step includes steps S22 to S25.

  First, a measurement step including step S21 is performed. In step S21, using an ellipsometer, incident light is incident on the substrate on which the second pattern is formed at a predetermined incident angle, and an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected are measured. This is a step of obtaining measurement data.

  As shown in FIG. 4, the incident light 101 is generated by the excitation head 103 of the ellipsometer 100. The incident light 101 is composed of light having two polarization components, p-polarized light and s-polarized light, so that the photodetector 104 can measure both the intensity and phase of the reflected light 102. The optical fiber 105 carries white light from a light source (not shown) to the excitation head 103. As white light, polarized light can be used and non-polarized light can also be used. The incident light 101 is guided onto the measurement object 110 mounted on the stage 107 so that the incident angle θ with respect to the normal line n of the measurement object 110 is 20 to 90 degrees.

  The reflected light 102 is diffracted and reflected to the opposite side of the normal line n of the incident angle θ and leaves the stage 107 at an angle θ equal to the incident angle θ. The reflected light 102 diffracted and reflected is received by a detector 104 that separates the reflected light into two polarization components, and is guided to a spectrometer 109 via an optical fiber 106. The optical signal guided to the spectrometer 109 is split and then converted into an electrical signal by a charge coupled device (not shown) and further sent to the CPU 215 shown in FIG. 4B.

  The angles Δ and Ψ are calculated by the signal processing system 200 shown in FIG. 4 (b). The signal processing system 200 includes a computer 210 including a CPU 215 and a memory 220, a display 201 connected to the computer 210, a keyboard 202, a printer 203, and a mouse 204. The CPU 215 is connected to the spectrometer 109. As described above, the measurement data converted from the spectrometer 109 into an electric signal by a charge coupled device (not shown) or the like is input to the CPU 215, and then the angles Δ and Ψ are calculated by performing predetermined calculations inside the CPU 215. .

  Further, the ellipsometer 100 shown in FIG. 4A can include an optical component for converging an irradiation region irradiated with the incident light 101 to a region having a smaller area than the measurement region of the object 110 to be measured. As a result, it is possible to focus the irradiation area to, for example, 50 μm × 50 μm or less.

  Next, a determination step including steps S22 to S25 is performed.

  Step S22 is a step of creating a cross-sectional shape model by modeling the cross-sectional shape of the second pattern using a new shape parameter that determines the cross-sectional shape of the side wall portion.

  FIG. 5A shows one cross section of the cross-sectional shape model 30 having a periodic structure. The cross section of the cross-sectional shape model 30 includes a substrate model 31 corresponding to the substrate, etched layer models 32a and 32b corresponding to the layer to be etched, and two side wall models 33a and 33b having a trapezoidal cross section. Of the cross-sectional shape model 30 shown in FIG. 5A, portions other than the substrate model 31 are considered to continue infinitely in the + Y direction and the −Y direction, and the periodic structure is repeated in the + X direction and the −X direction. Is considered. Further, the substrate model 31 is considered to continue infinitely in the + Y direction and the −Y direction, and in addition to being considered to repeat the periodic structure in the + X direction and the −X direction, it continues infinitely in the + Z direction. Is considered. The normal vector n for the diffraction grating is in the −Z direction, as shown in FIG.

  Here, as shown in FIG. 5C, variables associated with a mathematical analysis of a pattern model in which a cross-sectional shape model is repeatedly generated in the + X direction and the −X direction will be exemplified.

  λ is the wavelength of the incident light 101. θ is an angle between the normal vector n of the diffraction grating 110 and the incident light 101. The incident light 101 and the normal vector n constitute the incident surface 40.

  φ is an azimuth angle of the incident light 101, that is, an angle between the direction of the periodicity of the diffraction grating along the X axis in FIG. However, in the subsequent mathematical analysis, the azimuth angle φ is set to 0 degree.

  Ψ is an angle between the electric field vector E of the incident light 101 and the incident surface 40, that is, between the electric field vector E and a projection vector E ′ of the electric field vector E onto the incident surface 40. When the incident light 101 is polarized so that φ = 0 degrees and Ψ = 90 degrees, the electric field vector E is perpendicular to the incident plane 40 and the magnetic field vector H is in the incident plane 40 and is referred to as TE polarization. On the other hand, when the incident light 101 is polarized so that φ = 0 degrees and Ψ = 0 degrees, the magnetic field vector H is perpendicular to the incident plane 40, the electric field vector E is in the incident plane 40, and TM polarized light Called. Every plane polarization is a combination of in-phase TE and TM polarizations. The calculated amplitude ratio spectrum and phase difference spectrum are calculated by separately calculating the diffraction of the TE and TM components and summing them.

  Each shape parameter in the cross-sectional shape model 30 is composed of W1, D1, H1, θ1, W3, H3, and H4 as shown in FIGS. 5 (a) and 5 (b). W1 is the width of the bottom part of the side wall part models 33a and 33b. D1 is the distance between the side wall models 33a and 33b. H1 is the height of the side wall model 33a, 33b. θ1 is an inclination angle of the side surfaces of the side wall model 33a, 33b from the upper surface of the substrate. In addition, H3 and H4 are the thicknesses of the etched layer models 32a and 32b, respectively, and W3 is the width of the cross-sectional shape model 30.

  The shape parameters in the present invention include, for example, the bottom width of the side wall models 33a and 33b, the height of the side wall models 33a and 33b, and the inclination angle of the side surfaces of the side wall models 33a and 33b from the upper surface of the substrate, that is, W1. , H1 and θ1.

  Further, the cross-sectional shape model 30 in the present embodiment can be applied to a case where the shape of the side wall model 33a, 33b is more complicated.

  Next, step S23 is performed. In step S23, the calculated amplitude ratio spectrum and phase difference spectrum of the reflected light when the incident light is diffracted and reflected on the model pattern in which the cross-sectional shape model 30 is continuously formed periodically are calculated. It is a step to get.

  Next, step S24 is performed. Step S24 is a step of determining whether or not the calculation data most closely matches (matches) the measurement data.

  Specifically, using the PAS (Profile Application Server) included in the ODP system, the measurement spectrum measured by the optical system is compared with the calculated spectrum calculated by simulation from the structural model with different shape parameters. The degree of matching between data and calculation data is output as a numerical value. Here, for example, when the correlation coefficient obtained by comparing the calculation data with the measurement data is closer to 1 than the predetermined reference value using the correlation coefficient or the like as a determination parameter, it is determined that the matching is the best. be able to. If it is not closer to 1 than the predetermined reference value, the process returns to step S22, the shape parameter is changed, and the cross-sectional shape of the second pattern is modeled by using the shape parameter different from the previous one to create a cross-sectional shape model. Thereafter, the process proceeds to step S23, and the amplitude ratio spectrum and the phase difference spectrum in the calculation of the reflected light when the incident light is diffracted and reflected by the model pattern in which the cross-sectional shape model is periodically continuous are calculated. Get the data. Step S24 is performed again to determine whether the calculation data and the measurement data are the most consistent, and the shape parameters are changed until it can be determined that they are the most consistent, and steps S22, S23, and S24 are performed. Repeat.

The calculation data includes an amplitude ratio spectrum (P1) and a phase difference spectrum (P3). An example of the calculation data is shown in FIG. Here, P1 and P3 correspond to tan (Ψ) and e ^iΔ in equation (1), respectively.

  FIG. 6 shows the calculation results when the symmetrical models of the side wall models 33a and 33b are set with H1 = 50 nm, W1 = 30 nm, θ1 = 75 °, and D1 = 30 nm.

  Thereafter, when the calculated data and the measured data are most consistent, specifically, for example, when the correlation coefficient between the calculated data and the measured data is closer to 1 than a predetermined reference value, the next step S25 is performed. Proceed to

  Step S25 is a step of determining the cross-sectional shape of the second pattern by determining the model pattern and determining the shape parameter.

  Specifically, in step S24, each shape parameter of the cross-sectional shape model corresponding to the calculation data determined to be most consistent with the measurement data using PAS is output. Further, the shape parameter can be output with a resolution equal to or lower than the wavelength of incident light. That is, the width of the bottom of the side wall that defines the shape of the side wall, the height of the side wall, and the inclination angle of the side surface of the side wall from the upper surface of the substrate can be output as numerical values with a resolution of 1.0 nm or less.

  According to the pattern shape inspection method according to the present embodiment, in the so-called double patterning technology in which a pattern having a line and space of 30 nm or less is formed using a side wall, the width, height, The angle of the slope can be inspected with a very high resolution of 1 nm or less. Therefore, in the method of manufacturing a semiconductor device using the double patterning technique, the quality of the manufactured semiconductor device can be improved and the productivity of the manufacturing process can be improved.

  Furthermore, according to the pattern shape inspection method according to the present embodiment, the reflectance can be measured at a high speed in a few seconds per point, so that the distribution of shape parameters in the substrate can be measured in a short time. Therefore, the time required for the pattern shape inspection process of the semiconductor device is very short, and the throughput in the manufacturing process of the semiconductor device can be significantly reduced as compared with the case of using another pattern shape inspection method.

  If the shape of the sidewall is measured using the pattern shape inspection method according to the present invention, the pattern shape inspection process can be performed after various steps of the SWT process. That is, 1) Immediately after the film forming step shown in step S15 of FIG. 1, that is, the step of forming a silicon oxide film (or silicon oxynitride film) so as to cover the side surface of the first pattern made of an organic film, 2) Immediately after the etching step shown in step S16 of FIG. 1, ie, the step of etching back the formed silicon oxide film (or silicon oxynitride film) by dry etching or the like 3) shown in step S17 of FIG. Immediately after the second pattern forming step of removing the organic film by wet etching or the like, or 4) Immediately after the second pattern forming step, further cleaning is performed. Among these, 3) is a pattern shape inspection process in the present embodiment. 2) is a pattern shape inspection step in the second embodiment. Moreover, 1) is a pattern shape inspection process in the third embodiment.

(First modification of the first embodiment)
Next, a pattern shape inspection method according to a first modification of the first embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification. However, in the following text, the same reference numerals are given to the parts described above, and the description may be omitted (the same applies to the following modified examples and embodiments).

  The pattern shape inspection method according to the present modification is different from the pattern shape inspection method according to the first embodiment in that a database that stores a plurality of calculation data corresponding to a plurality of different shape parameters in advance is used.

  As shown in FIG. 7, the pattern shape inspection method according to this modification performs a database creation step in advance before the pattern shape inspection step including the measurement step and the determination step. The database creation step includes steps S31 to S33. The measurement step includes step S34, and the determination step includes steps S35 to S37.

  Prior to the pattern shape inspection process, a database creation step including steps S31 to S33 is performed in advance. First, step S31 is performed. Step S31 is a step of creating a cross-sectional shape model by modeling the cross-sectional shape of the second pattern using a new shape parameter that determines the cross-sectional shape of the side wall, and the pattern shape according to the first embodiment This corresponds to step S22 in the inspection process.

  Next, step S32 is performed. In step S32, the calculated amplitude ratio spectrum and phase difference spectrum of the reflected light when the incident light is diffracted and reflected on the model pattern in which the cross-sectional shape model is periodically continuously formed are calculated, and the calculated data is stored in the database. And corresponds to step S23 in the pattern shape inspection step according to the first embodiment.

  Next, step S33 is performed. Step S33 is a step of determining whether the calculation data stored in the database is sufficient.

  Specifically, it is determined whether the number of calculation data to be calculated by changing the shape parameter is larger than a predetermined reference number. If not, the process returns to step S31 to change the shape parameter. The cross-sectional shape model is created by modeling the cross-sectional shape of the second pattern using shape parameters different from the previous ones. Thereafter, the process proceeds to step S32, and the amplitude ratio spectrum and the phase difference spectrum in the calculation of the reflected light when the incident light is diffracted and reflected on the model pattern in which the cross-sectional shape model is periodically continuous are calculated. Store data in a database. Step S33 is performed again, and the shape parameters are changed and steps S31, S32, and S33 are repeated until it can be determined whether the number of calculation data is sufficient.

  Thereafter, when the number of calculation data is sufficient, specifically, for example, when the number of calculation data is greater than a predetermined reference number, the database creation step is terminated.

  With the database created, the pattern shape inspection process is started. First, the measurement step including step S34 is performed. In step S34, using an ellipsometer, incident light is incident on the substrate on which the second pattern is formed at a predetermined incident angle, and an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected are measured. This is a step of obtaining measurement data. Step S34 corresponds to step S21 in the pattern shape inspection step according to the first embodiment.

  Next, a determination step including steps S35 to S37 is performed. First, step S35 is performed. Step S35 is a step of selecting calculation data stored in the database.

  Next, step S36 is performed. Step S36 is a step of determining whether or not the selected calculation data most closely matches the measurement data.

  Specifically, using an ODP system including PAS, the measured spectrum measured by the optical system is compared with the calculated spectrum calculated by simulation from the structural model by changing the shape parameter, and the measured data and calculated data are compared. The degree of matching is output as a numerical value. Here, for example, when the correlation coefficient obtained by comparing the calculation data with the measurement data is closer to 1 than the predetermined reference value using the correlation coefficient or the like as a determination parameter, it is determined that the matching is the best. be able to. If it is not closer to 1 than the predetermined reference value, the process returns to step S35, and another data stored in the database is selected. Step S36 is performed again to determine whether the calculation data and the measurement data are most consistent, and the shape parameter is changed and steps S35 and S36 are repeated until it can be determined that the calculation data is the most consistent.

  Thereafter, when the calculated data and the measured data are most consistent, specifically, for example, when the correlation coefficient between the calculated data and the measured data is closer to 1 than a predetermined reference value, the next step S37. Proceed to

  Step S37 is a step of determining a cross-sectional shape of the second pattern by determining a model pattern and determining a shape parameter.

  Specifically, in step S36, each shape parameter of the cross-sectional shape model corresponding to the calculation data determined to be the most consistent with the measurement data using the ODP system including PAS is output. Further, the shape parameter can be output with a resolution equal to or lower than the wavelength of incident light. That is, the width of the bottom of the side wall that defines the shape of the side wall, the height of the side wall, and the inclination angle of the side surface of the side wall from the upper surface of the substrate can be output as numerical values with a resolution of 1.0 nm or less.

  By performing the semiconductor device manufacturing method including the pattern shape inspection method according to the present modification and the pattern shape inspection process performed using the pattern shape inspection method according to the present modification, the shape parameters are changed in advance and different shape parameters are obtained. Since the calculation data corresponding to the cross-sectional shape model corresponding to is calculated and the stored database is prepared, the time required for the pattern shape inspection process can be further shortened.

(Second modification of the first embodiment)
Next, a pattern shape inspection method according to a second modification of the first embodiment of the present invention will be described with reference to FIG.

  FIG. 8 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to this modification.

  The pattern shape inspection method according to the first embodiment is such that an alarm is output when the determined shape parameter is not between the upper limit reference value and the lower limit reference value. Is different.

  As shown in FIG. 8, the pattern shape inspection method according to the present modification performs a determination step after performing a measurement step and a determination step. The determination step includes step S46 and step S47. The measurement step includes step S41, and the determination step includes steps S42 to S45.

  First, a measurement step including step S41 and a determination step including steps S42 to S45 are performed. Step S41 corresponds to step S21 in the pattern shape inspection process according to the first embodiment. Steps S42 to S45 correspond to steps S22 to S25 in the pattern shape inspection process according to the first embodiment, respectively.

  Thereafter, a determination step including steps S46 and S47 is performed. First, step S46 is performed. In step S46, it is determined whether the shape parameter determined in step S45 is not included in the range between the predetermined upper limit reference value and the lower limit reference value. Specifically, when the determined shape parameter is smaller than a predetermined upper limit reference value and larger than the lower limit reference value, the pattern shape inspection process is terminated without performing step S47. If it is larger than the predetermined upper limit reference value or smaller than the predetermined lower limit reference value, the process proceeds to step S47.

  Step S47 is a step of outputting an alarm. When the determined shape parameter is not included in the range between the predetermined upper limit reference value and the lower limit reference value, an alarm is output. On the other hand, when the determined shape parameter is included in a range between the predetermined upper limit reference value and the lower limit reference value, no alarm is output.

  Specifically, for example, shape parameters such as the width W1 of the bottom portion of the side wall portion shown in FIG. 5B, the height H1 of the side wall portion, and the inclination angle θ1 of the side surface of the side wall portion from the upper surface of the substrate are determined and determined. When the set shape parameter is larger than a preset upper limit reference value or smaller than a preset lower limit reference value, the above-described PAS outputs a determination result and sends it to a host computer that manages the manufacturing process of the semiconductor device Alternatively, an alarm can be output to the controller of the manufacturing apparatus equipped with the ODP system and PAS.

  In addition, when performing the pattern shape inspection process according to this modification, the ODP measuring apparatus and the PAS are installed in a manufacturing apparatus that performs an etching process for etching a silicon oxide film (or silicon oxynitride film), and IM (Integrated Metrology) It may be configured to perform a pattern shape inspection process on a substrate immediately after processing, and is installed as a single measuring device (Stand alone) near a manufacturing apparatus, and the processed substrates are collected once for each lot. Then, the pattern shape inspection step may be performed.

  In particular, in the double patterning technology using the SWT process, it is not desirable to install the ODP system in all processing manufacturing apparatuses because it increases the price of the semiconductor manufacturing apparatus. Even in such a case, in the etching apparatus for etching the silicon oxide film (or silicon oxynitride film), by mounting IM on the load port for loading the wafer, the dimension of the cross-sectional shape of the side wall is the upper limit standard. It can be monitored that it is in the range between the value and the lower reference value. Further, based on the result of the monitoring, it is possible to identify a process step and a processing apparatus that cause a so-called defect in which the dimension of the cross-sectional shape is not in the range between the upper limit reference value and the lower limit reference value. .

  In addition, a host computer (not shown) that has received an alarm (alarm) in which PAS has occurred immediately stops processing the lot being processed in the target manufacturing apparatus, and does not process the lot remaining in the manufacturing apparatus. You may make it send the instruction | indication to collect | recover to a load port, Furthermore, the high-order computer goes to the board | substrate reproduction | regeneration processing process which peels an oxide film and an organic film by making a target lot into the next processing process to a transfer robot. An instruction to convey may be sent.

  In this modification, by determining which shape parameter out of the shape parameters used in the cross-sectional shape model 30 is out of the range between the upper limit reference value and the lower limit reference value, a method for manufacturing a semiconductor device It is possible to specify which process has a cause of the defect. For example, when D1 shown in FIG. 5B, that is, the interval between the side wall models 33a and 33b is smaller than the lower limit reference value, the organic film made of the BARC film shown in FIG. 2B and step S14 in FIG. If the etching time for etching 13 is too long, the cause can be specified. When the width W1 shown in FIG. 5B, that is, the width of the bottom of the sidewall models 33a and 33b is smaller than the lower limit reference value, the silicon oxide film (shown in FIG. 2B (f) and step S16 in FIG. Alternatively, the cause can be specified to be because the etching time of the silicon oxynitride film) is too long. Furthermore, when W1 shown in FIG. 5B, that is, the width of the bottom of the side wall models 33a and 33b is larger than the upper reference value, the film formation time for forming the silicon oxide film (or silicon oxynitride film) is increased. The cause can be identified as being too long or because the supply amount of the process gas is excessive.

  Further, even when these shape parameters vary in the plane of the substrate or between the substrates, it is possible to specify the process that caused the variation of the shape parameter and the processing apparatus corresponding to the process.

(Third modification of the first embodiment)
Next, a pattern shape inspection method according to a third modification of the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 9 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification. FIG. 10 is a diagram for explaining the pattern shape inspection method according to this modification, and is a diagram showing a cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern. FIG. 10A is a view showing the entire cross-sectional shape model, and FIG. 10B is an enlarged view showing the periphery of the side wall portion. FIG. 11 is a diagram for explaining the pattern shape inspection method according to this modification, and the calculation data of the amplitude ratio spectrum and the phase difference spectrum of the reflected light in which the incident light is diffracted and reflected by the model pattern made of the cross-sectional shape model. It is a graph which shows an example.

  The pattern shape inspection method according to this modification uses the first and second shape parameters corresponding to the first and second side wall portions to inspect the asymmetry of the cross-sectional shapes of the first and second side wall portions. This is different from the pattern shape inspection method according to the first embodiment.

  As shown in FIG. 9, the pattern shape inspection method according to the present modification includes a measurement step and a determination step. The measurement step includes step S51, and the determination step includes steps S52 to S55.

  First, a measurement step including step S51 is performed. Step S51 corresponds to step S21 in the pattern shape inspection step according to the first embodiment.

  Next, a determination step including steps S52 to S55 is performed.

  Step S52 is a step of creating a cross-sectional shape model by modeling the cross-sectional shape of the second pattern using a new shape parameter for determining the cross-sectional shape of the side wall portion. However, unlike step S22 in the pattern shape inspection step according to the first embodiment, a cross-sectional shape model 30a representing the asymmetry of the left and right side wall portions is used.

  FIG. 10A shows one cross section of a cross-sectional shape model 30a having a periodic structure. The cross section of the cross-sectional shape model 30a includes a substrate model 31 corresponding to the substrate, etched layer models 32a and 32b corresponding to the layer to be etched, and two side wall models 33a and 33b having a trapezoidal cross section. Of the cross-sectional shape model 30a shown in FIG. 10A, the portion other than the substrate model 31 is considered to continue infinitely in the + Y direction and the −Y direction, and the periodic structure is repeated in the + X direction and the −X direction. Is considered. Further, the substrate model 31 is considered to continue infinitely in the + Y direction and the −Y direction, and in addition to being considered to repeat the periodic structure in the + X direction and the −X direction, it continues infinitely in the + Z direction. Is considered.

  Further, as shown in FIGS. 10A and 10B, the shape parameters in the cross-sectional shape model 30a are different from those of the first embodiment in that the asymmetry of the left and right side wall models 33a and 33b is as follows. In order to express, it consists of W1, W2, H1, H2, θ1, θ2, D1, W3, H3, and H4. W1 and W2 are the widths of the bottoms of the side wall models 33a and 33b, respectively. H1 and H2 are the heights of the side wall part models 33a and 33b, respectively. θ1 and θ2 are inclination angles of the side surfaces of the side wall models 33a and 33b from the upper surface of the substrate. D1 is the distance between the side wall models 33a and 33b. In addition, W3 is the width of the cross-sectional shape model 30a, and H3 and H4 are the thicknesses of the etched layer models 32a and 32b, respectively.

  The first shape parameters in the present invention are the width W1 of the bottom of the right side wall model 33a, the height H1 of the right side wall model 33a, and the inclination angle of the side surface of the right side wall model 33a from the top surface of the substrate. θ1 can be set. Further, the second shape parameter in the present invention includes the width W2 of the bottom of the left side wall model 33b, the height H2 of the left side wall model 33b, and the inclination angle of the side surface of the left side wall model 33b from the top surface of the substrate. θ2 can be set.

  Next, step S53 is performed. Step S53 is the same as step S23 in the pattern shape inspection step according to the first embodiment, except that the cross-sectional shape model 30a uses the first and second shape parameters representing asymmetry.

  Next, step S24 is performed. Step S24 is a step of determining whether or not the calculation data most closely matches (matches) the measurement data. Step S54 is also the same as step S24 in the pattern shape inspection step according to the first embodiment, except that the cross-sectional shape model uses the first and second shape parameters representing asymmetry.

The calculation data includes an amplitude ratio spectrum (P1) and a phase difference spectrum (P3). An example of the calculation data is shown in FIG. Here, P1 and P3 correspond to tan (Ψ) and e ^iΔ in equation (1), respectively.

  In FIG. 11A, H1 = 50 nm and H2 = 0 nm, and the other shape parameters are W1 = W2 = 30 nm, θ1 = θ2 = 75 °, D1 = 30 nm, and the asymmetric cross sections of the side wall models 33a and 33b. It is a calculation result when a shape model is set. For comparison, FIG. 11B shows that the side wall portion model 33a has H1 = H2 = 50 nm, and other shape parameters are W1 = W2 = 30 nm, θ1 = θ2 = 75 °, and D1 = 30 nm. It is a calculation result when the symmetric model of 33b is set. Note that the calculation data in FIG. 11B is the same as the calculation data in FIG.

  Comparing FIG. 11 (a) and FIG. 11 (b), the shape of the P1 spectrum in the vicinity of 300 nm is different, and the minimum of P1 in the vicinity of 300 nm in the calculation result of the asymmetric cross-sectional shape model shown in FIG. It can be seen that the value is larger than the minimum value of P1 in the vicinity of 300 nm in the calculation result of the symmetrical cross-sectional shape model shown in FIG. In this way, if the symmetry is lost, the spectrum shape is greatly different. Therefore, the left-right symmetry of the side wall can be easily measured by quantifying the degree of matching between the calculated data and the measured data. can do.

  Thereafter, when the calculated data and the measured data are most consistent, specifically, for example, when the correlation coefficient between the calculated data and the measured data is closer to 1 than a predetermined reference value, the next step S55 is performed. Then, the first and second shape parameters are determined, and the cross-sectional shape of the second pattern is determined. Step S55 is the same as step S25 in the pattern shape inspection step according to the first embodiment, except that the cross-sectional shape model 30a uses the first and second shape parameters representing asymmetry.

(Fourth modification of the first embodiment)
Next, a pattern shape inspection method according to a fourth modification of the first embodiment of the present invention will be described with reference to FIG.

  FIG. 12 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to the present modification is a third modification of the first embodiment in that a database that stores a plurality of calculation data corresponding to a plurality of different first and second shape parameters in advance is used. This is different from the pattern shape inspection method according to the example.

  As shown in FIG. 12, the pattern shape inspection method according to the present modification performs a database creation step in advance before the pattern shape inspection step including the measurement step and the determination step. The database creation step includes steps S61 to S63. The measurement step includes step S64, and the determination step includes steps S65 to S67.

  In addition, each step from step S61 to step S67 in the present modification is the same as that of the first embodiment except that the cross-sectional shape model 30a uses the first and second shape parameters representing asymmetry. This is the same as steps S31 to S37 in the modification.

  The first and second shape parameters can be obtained in advance by performing a semiconductor device manufacturing method including a pattern shape inspection method according to the present modification and a pattern shape inspection process performed using the pattern shape inspection method according to the present variation. Since the calculation data corresponding to the cross-sectional shape models corresponding to the different first and second shape parameters is calculated and the stored database is prepared, the time required for the pattern shape inspection process is further reduced. Can do.

(Fifth modification of the first embodiment)
Next, a pattern shape inspection method according to a fifth modification of the first embodiment of the present invention will be described with reference to FIG.

  FIG. 13 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to this modification is the third embodiment of the first embodiment in that an alarm is output when the dimensional difference between the determined first and second shape parameters is larger than a predetermined reference value. This is different from the pattern shape inspection method according to the modified example.

  As shown in FIG. 13, the pattern shape inspection method according to the present modification performs a determination step after performing a measurement step and a determination step. The determination step includes step S76 and step S77. The measurement step includes step S71, and the determination step includes steps S72 to S75.

  In addition, each step of step S71 to step S75 in this modification example is the second of the first embodiment except that the cross-sectional shape model 30a uses the first and second shape parameters representing asymmetry. This is the same as steps S41 to S45 in the modification.

  In the determination step including step S76 and step S77, it is determined in step S76 whether the dimensional difference between the first shape parameter and the second shape parameter determined in step S75 is greater than or equal to a predetermined reference value. Specifically, when the dimensional difference between the determined first shape parameter and the second shape parameter is smaller than a predetermined reference value, the pattern shape inspection process is terminated without performing step S77. If the dimensional difference between the first shape parameter and the second shape parameter is larger than the predetermined reference value, the process proceeds to step S77.

  Step S77 is a step of outputting an alarm. When the dimensional difference between the determined first shape parameter and the second shape parameter is larger than a predetermined reference value, an alarm is output. On the other hand, when the dimensional difference between the determined first shape parameter and the second shape parameter is smaller than a predetermined reference value, no alarm is output.

  In the present modification, for which shape parameter of the cross-sectional shape model 30a, it is determined whether the dimensional difference between the first shape parameter and the second shape parameter is greater than a predetermined reference value, whereby a method for manufacturing a semiconductor device It is possible to specify which process has a cause of failure. For example, when the dimensional difference between W1 and W2 shown in FIG. 10B is larger than the reference value, the silicon oxide film (or silicon oxynitride film) shown in FIG. 2B (f) and step S16 in FIG. In the etch back process, the cause can be identified as being due to some problem in the apparatus.

(Second Embodiment)
Next, a method for manufacturing a semiconductor device and a pattern shape inspection method according to the second embodiment of the present invention will be described with reference to FIGS.

  First, a method for manufacturing a semiconductor device according to the present embodiment will be described with reference to FIG.

  FIG. 14 is a flowchart for explaining the procedure of each step of the semiconductor device manufacturing method according to the present embodiment.

  The semiconductor device manufacturing method according to the present embodiment is different from the semiconductor device manufacturing method according to the first embodiment in that the pattern shape inspection method is performed between the etching step and the second pattern formation step. To do.

  As shown in FIG. 14, the method of manufacturing a semiconductor device according to the present embodiment includes a first pattern forming step, a film forming step, an etching step, a pattern shape inspection step, a second pattern forming step, Etching the layer to be etched. The first pattern forming step includes steps S81 to S84, the film forming step includes step S85, the etching step includes step S86, and the pattern shape inspection step includes step S87. The second pattern formation step includes a step S88, and the step of etching the etching target layer includes a step S89. That is, the method for manufacturing a semiconductor device according to the present embodiment is characterized in that a pattern shape inspection step is performed after the second pattern formation step.

  Steps S81 to S86 in the present embodiment correspond to steps S11 to S16 according to the first embodiment. Steps S87, S88, and S89 in the present embodiment correspond to Step S18, Step S17, and Step S19 according to the first embodiment, respectively. That is, the semiconductor device manufacturing method according to the present embodiment corresponds to the semiconductor device manufacturing method according to the first embodiment in which the procedures of Step S17 and Step S18 are reversed.

  Next, the pattern shape inspection method according to the present embodiment will be described with reference to FIGS.

  FIG. 15 is a diagram for explaining the pattern shape inspection method according to the present embodiment, and is a diagram showing a cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern.

  The pattern shape inspection method according to the present embodiment is the pattern according to the first embodiment except that the first pattern made of the organic film is not removed in the cross-sectional shape of the object to be measured for inspecting the pattern shape. This is the same as the shape inspection method, and the steps S21 to S25 shown in FIG. 3 are performed.

  Each shape parameter in the cross-sectional shape model 30b is composed of W1, H1, θ1, and D1, as shown in FIG. W1 is the width of the bottom part of the side wall part models 33a and 33b. H1 is the height of the side wall model 33a, 33b. θ1 is an inclination angle of the side surfaces of the side wall model 33a, 33b from the upper surface of the substrate. D1 is the distance between the side wall part models 33a and 33b and the width of the first pattern model 34. This point is different from the cross-sectional shape model 30 in the first embodiment.

  As described above, by performing the pattern shape inspection method according to this embodiment, the cross-sectional shape immediately after the step of etching back the silicon oxide film (or silicon oxynitride film) by dry etching or the like can be inspected.

(First Modification of Second Embodiment)
Next, with reference to FIG. 16, a method for manufacturing a semiconductor device according to a first modification of the second embodiment of the present invention will be described.

  FIG. 16 is a flowchart for explaining the procedure of each step of the semiconductor device manufacturing method according to the present modification.

  The manufacturing method of the semiconductor device according to the present modification example uses the etching time of the subsequent substrate as the etching time of the previous substrate when the shape parameter determined in the pattern shape inspection process of the previous substrate is smaller than a predetermined lower limit value. It is characterized by being made shorter.

  As shown in FIG. 16, the semiconductor device manufacturing method according to the present modification is the first semiconductor device manufacturing method including steps S181 to S187, which are the same as steps S81 to S87 shown in FIG. After the first manufacturing process is performed on the first substrate, the semiconductor device manufacturing method including steps S281 to S287 that are the same as steps S81 to S87 shown in FIG. 14 is used as the second manufacturing process. This is performed on the second substrate. Further, step S180 is included before the first manufacturing process, and steps S188 and S189 to S280 are included between the first manufacturing process and the second manufacturing process.

  First, step S180 is performed. Step S180 is a step of setting an etching time for etching the silicon oxide film (or silicon oxynitride film).

  Next, a first manufacturing process for manufacturing a semiconductor device on the first substrate is performed. Similar to the second embodiment, steps S181 to S187 are performed.

  Next, step S188 is performed. Step S188 is a step of determining whether or not the shape parameter determined in step S185 of the first manufacturing process is smaller than the lower limit reference value. Specifically, the determination can be made with respect to W1, which is the width of the bottom of the side wall models 33a and 33b shown in FIG. As a result of the determination in step S188, if W1 is smaller than the predetermined lower limit reference value, the process proceeds to step S189, and the etching time is set shorter than that for the first substrate (during the first manufacturing process). If it is determined in step S188 that W1 is not smaller than the predetermined lower limit reference value, the process proceeds to step S280, and the etching time is set to be the same as that for the first substrate (during the first manufacturing process). To do.

  Next, a second manufacturing process for manufacturing a semiconductor device on the second substrate is performed. Similar to the second embodiment, steps S281 to S287 are performed.

  As described above, by performing the semiconductor device manufacturing method including the pattern shape inspection method according to this modification and the pattern shape inspection process according to the pattern shape inspection method according to this modification, a highly accurate pattern can be obtained in an appropriate process. Since the inspection of the shape can be performed and the process recipe can be adjusted in an appropriate process based on the result, the purpose of the double patterning technology of forming a fine structure exceeding the resolution limit of the exposure machine can be achieved. it can.

  In addition, in this modification, although the example of the procedure which performs all the steps of a 2nd manufacturing process after all the steps of a 1st manufacturing process is shown, step S284 in a 2nd manufacturing process is a 1st manufacturing process. Step S184 may be performed after step S184, and other steps S181 to S183 and S185 to S187 and steps S281 to S283 and S285 to S287 are the same as the first manufacturing process and the second step. These manufacturing steps may be performed simultaneously, and the second manufacturing step may be performed before the first manufacturing step.

(Second modification of the second embodiment)
Next, a pattern shape inspection method according to a second modification of the second embodiment will be described with reference to FIG.

  FIG. 17 is a diagram for explaining the pattern shape inspection method according to this modification, and is a diagram showing a cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern.

  The pattern shape inspection method according to this modification uses the first and second shape parameters corresponding to the first and second side wall portions to inspect the asymmetry of the cross-sectional shapes of the first and second side wall portions. This is different from the pattern shape inspection method according to the second embodiment.

  The pattern shape inspection method according to this modification is the third shape of the first embodiment, except that the first pattern made of the organic film is not removed in the cross-sectional shape of the object to be measured for inspecting the pattern shape. This is the same as the pattern shape inspection method according to the modified example, and the steps S51 to S55 shown in FIG. 9 are performed.

  Further, each shape parameter in the cross-sectional shape model 30c includes W1, W2, H1, H2, θ1, θ2, and D1, as shown in FIG. W1 and W2 are the widths of the bottoms of the side wall models 33a and 33b, respectively. H1 and H2 are the heights of the side wall part models 33a and 33b, respectively. θ1 and θ2 are inclination angles of the side surfaces of the side wall models 33a and 33b from the upper surface of the substrate. D1 is the distance between the side wall part models 33a and 33b and the width of the first pattern model 34. This point is different from the cross-sectional shape model 30a in the third modified example of the first embodiment. .

  As described above, by performing the pattern shape inspection method according to this modification, it is possible to inspect the asymmetry of the cross-sectional shape immediately after the step of etching back the silicon oxide film (or silicon oxynitride film) by dry etching or the like. .

(Third embodiment)
Next, a semiconductor device manufacturing method and a pattern shape inspection method according to the third embodiment of the present invention will be described with reference to FIGS.

  First, a method for manufacturing a semiconductor device according to the present embodiment will be described with reference to FIG.

  FIG. 18 is a flowchart for explaining the procedure of each step of the semiconductor device manufacturing method according to the present embodiment.

  The semiconductor device manufacturing method according to the present embodiment is different from the semiconductor device manufacturing method according to the first embodiment in that the pattern shape inspection method is performed between the film forming step and the etching step.

  As shown in FIG. 18, the manufacturing method of the semiconductor device according to the present embodiment includes a first pattern forming step, a film forming step, a pattern shape inspection step, an etching step, a second pattern forming step, Etching the layer to be etched. The first pattern forming step includes steps S91 to S94, the film forming step includes step S95, the pattern shape inspection step includes step S96, and the etching step includes step S97. The second pattern forming process includes the process of step S98, and the process of etching the etching target layer includes the process of step S99. That is, the method for manufacturing a semiconductor device according to the present embodiment is characterized in that a pattern shape inspection process is performed after the film formation process.

  Next, the pattern shape inspection method according to the present embodiment will be described with reference to FIGS. 19 and 20.

  FIG. 19 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present embodiment. FIG. 20 is a diagram for explaining the pattern shape inspection method according to the present embodiment, and is a diagram showing a cross-sectional shape model that models the cross-sectional shape of a silicon oxide film (or silicon oxynitride film).

  The pattern shape inspection method according to the present embodiment is different from the pattern shape inspection method according to the first embodiment in that the cross-sectional shape of the silicon oxide film (or silicon oxynitride film) is inspected.

  The pattern shape inspection method according to the present embodiment includes a measurement step and a determination step, as shown in FIG. The measurement step includes step S101, and the determination step includes steps S102 to S105. The pattern shape inspection method according to the present embodiment is the same as the pattern shape inspection method according to the first embodiment except that the cross-sectional shape of the silicon oxide film (or silicon oxynitride film) is inspected. That is, each step from step S101 to step S105 shown in FIG. 19 corresponds to step S21 to step S25 shown in FIG.

  Each shape parameter in the cross-sectional shape model 30d can include WT1 as shown in FIG. WT1 is the thickness of the silicon oxide film model 33c.

  As described above, by performing the pattern shape inspection method according to this embodiment, the cross-sectional shape immediately after the step of forming the silicon oxide film (or silicon oxynitride film) can be inspected.

(First modification of the third embodiment)
Next, a pattern shape inspection method according to a first modification of the third embodiment of the present invention will be described with reference to FIG.

  FIG. 21 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to the present modification is a third embodiment in that a database that stores a plurality of calculation data corresponding to the thicknesses of a plurality of different silicon oxide films (or silicon oxynitride films) in advance is used. This is different from the pattern shape inspection method according to FIG.

  In the pattern shape inspection method according to this modification, as shown in FIG. 21, a database creation step is performed in advance before the pattern shape inspection step including the measurement step and the determination step. The database creation step includes steps S111 to S113. The measurement step includes step S114, and the determination step includes steps S115 to S117.

  Further, each step from step S111 to step S117 in the present modification is the same as that of the first embodiment except that the cross-sectional shape model 30d uses the thickness WT1 of the silicon oxide film (or silicon oxynitride film). This is the same as steps S31 to S37 in the first modification.

  A silicon oxide film (or oxynitridation) is also performed in advance by performing a semiconductor device manufacturing method including a pattern shape inspection method according to the present modification and a pattern shape inspection method according to the present embodiment. To change the thickness of the silicon film), calculate the calculation data corresponding to the cross-sectional shape model corresponding to the thickness of the different silicon oxide film (or silicon oxynitride film), and prepare the stored database, The time required for the pattern shape inspection process can be shortened.

(Second modification of the third embodiment)
Next, a pattern shape inspection method according to a second modification of the third embodiment of the present invention will be described with reference to FIG.

  FIG. 22 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to this modification is the first point that an alarm is output when the determined thickness of the silicon oxide film (or silicon oxynitride film) is not between the upper limit reference value and the lower limit reference value. This is different from the pattern shape inspection method according to the third embodiment.

  As shown in FIG. 22, the pattern shape inspection method according to the present modification performs a determination step after performing a measurement step and a determination step. The determination step includes step S126 and step S127. The measurement step includes step S121, and the determination step includes steps S122 to S125.

  Steps S121 to S127 in this modification are different from those in step S41 in the second modification of the first embodiment except that the cross-sectional shape model 30d uses the thickness WT1 of the silicon oxide film. To step S47.

  In this modification, whether or not there is a cause of a defect in the silicon oxide film formation process by determining whether the thickness of the silicon oxide film is in a range between a predetermined upper limit reference value and a lower limit reference value. Can be specified.

(Third Modification of Third Embodiment)
Next, a pattern shape inspection method according to a third modification of the third embodiment of the present invention will be described with reference to FIGS.

  FIG. 23 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification. FIG. 24 is a diagram for explaining the pattern shape inspection method according to the present modification, and is a diagram showing a cross-sectional shape model that models the cross-sectional shape of the silicon oxide film.

  The pattern shape inspection method according to this modification uses the first and second thicknesses corresponding to the thickness of the silicon oxide film covering both sides of the first pattern made of an organic film, and both sides of the first pattern. This is different from the pattern shape inspection method according to the third embodiment in that the asymmetry of the cross-sectional shape of the silicon oxide film covering the film is inspected.

  The pattern shape inspection method according to this modification includes a measurement step and a determination step, as shown in FIG. The measurement step includes step S131, and the determination step includes steps S132 to S135.

  Steps S131 to S135 in this modification are different from steps S51 to S135 in the third modification of the first embodiment except that the cross-sectional shape model 30e uses the thickness of the silicon oxide film. Same as step S55.

  Further, as shown in FIG. 24, each shape parameter in the cross-sectional shape model 30e includes WT1 and WT2 in order to represent the asymmetry of the silicon oxide film model 33d, unlike the third embodiment.

  In this modification, as described in the third modification of the first embodiment, the spectral shape is greatly different if the left-right symmetry is lost. ) Is quantified, the symmetry of the thickness of the silicon oxide film can be easily measured.

(Fourth modification of the third embodiment)
Next, a pattern shape inspection method according to a fourth modification of the third embodiment of the present invention will be described with reference to FIG.

  FIG. 25 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to the present modification uses a database for storing a plurality of calculation data corresponding to a plurality of different first and second thicknesses in advance, and the pattern shape inspection method according to the third embodiment. It is different from the method.

  As shown in FIG. 25, the pattern shape inspection method according to the present modification performs a database creation step in advance before the pattern shape inspection step including the measurement step and the determination step. The database creation step includes steps S141 to S143. The measurement step includes step S144, and the determination step includes steps S145 to S147.

  In addition, each step of step S141 to step S147 in this modification example is the first of the third embodiment, except that the cross-sectional shape model 30e uses the first and second thicknesses representing asymmetry. This is the same as steps S111 to S117 in the modification.

  The first and second thicknesses can also be obtained in advance by performing a semiconductor device manufacturing method including a pattern shape inspection method according to the present modification and a pattern shape inspection process performed using the pattern shape inspection method according to the present modification. Since the calculation data corresponding to the cross-sectional shape models corresponding to the different first and second thicknesses is calculated and the stored database is prepared, the time required for the pattern shape inspection process is further reduced. Can do.

(Fifth modification of the third embodiment)
Next, a pattern shape inspection method according to a fifth modification of the third embodiment of the present invention will be described with reference to FIG.

  FIG. 26 is a flowchart for explaining the procedure of each step of the pattern shape inspection method according to the present modification.

  The pattern shape inspection method according to the present modification is such that an alarm is output when the difference between the determined first and second thicknesses is greater than a predetermined reference value, and the pattern shape according to the third embodiment It is different from the inspection method.

  As shown in FIG. 26, the pattern shape inspection method according to the present modification performs a determination step after performing a measurement step and a determination step. The determination step includes step S156 and step S157. The measurement step includes step S151, and the determination step includes steps S152 to S155.

  In addition, each step of step S151 to step S157 in the present modification is the second of the third embodiment except that the cross-sectional shape model 30e uses the first and second thicknesses representing asymmetry. This is the same as steps S121 to S127 in the modification.

  In the determination step including step S156 and step S157, it is determined in step S156 whether the dimensional difference between the first thickness WT1 and the second thickness WT2 determined in step S155 is equal to or greater than a predetermined reference value. To do. Specifically, when the dimensional difference between the determined first thickness WT1 and second thickness WT2 is smaller than a predetermined reference value, the pattern shape inspection process is terminated without performing step S157. When the determined dimensional difference between the first thickness WT1 and the second thickness WT2 is larger than a predetermined reference value, the process proceeds to step S157.

  Step S157 is a step of outputting an alarm. When the determined dimensional difference between the first thickness WT1 and the second thickness WT2 is greater than a predetermined reference value, an alarm is output. On the other hand, when the determined dimensional difference between the first thickness WT1 and the second thickness WT2 is smaller than a predetermined reference value, no alarm is output.

  In this modification, it is determined that there is some problem in the silicon oxide film deposition apparatus by determining whether the degree of symmetry of the thickness of the silicon oxide film is more asymmetric than a predetermined reference value. Can be specified.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

It is a flowchart for demonstrating the procedure of each process of the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the process of the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention, and is sectional drawing (the 1) which shows the structure of the semiconductor device in each process typically. It is a figure for demonstrating the process of the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention, and is sectional drawing (the 2) which shows the structure of the semiconductor device in each process typically. It is a figure for demonstrating the process of the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention, and is sectional drawing (the 3) which shows the structure of the semiconductor device in each process typically. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 1st Embodiment of this invention, and is a figure which shows typically the structure of a reflectance measuring device. It is a figure for demonstrating the pattern shape inspection method which concerns on the 1st Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the 2nd pattern. It is a figure for demonstrating the pattern shape inspection method which concerns on the 1st Embodiment of this invention, and the amplitude ratio spectrum and phase difference spectrum of the reflected light by which incident light is diffracted and reflected by the model pattern which consists of a cross-sectional shape model It is a graph which shows an example of calculation data. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 1st modification of the 1st Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 2nd modification of the 1st Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 3rd modification of the 1st Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 3rd modification of the 1st Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the 2nd pattern. It is a figure for demonstrating the pattern shape inspection method which concerns on the 3rd modification of the 1st Embodiment of this invention, and the amplitude ratio of the reflected light in which incident light is diffracted and reflected by the model pattern which consists of a cross-sectional shape model It is a graph which shows an example of the calculation data of a spectrum and a phase difference spectrum. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 4th modification of the 1st Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 5th modification of the 1st Embodiment of this invention. It is a flowchart for demonstrating the procedure of each process of the manufacturing method of the semiconductor device which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 2nd Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the 2nd pattern. It is a flowchart for demonstrating the procedure of each process of the manufacturing method of the semiconductor device which concerns on the 1st modification of the 2nd Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 2nd modification of the 2nd Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the 2nd pattern. It is a flowchart for demonstrating the procedure of each process of the manufacturing method of the semiconductor device which concerns on the 3rd Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 3rd Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the silicon oxide film. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 1st modification of the 3rd Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 2nd modification of the 3rd Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 3rd modification of the 3rd Embodiment of this invention. It is a figure for demonstrating the pattern shape inspection method which concerns on the 3rd modification of the 3rd Embodiment of this invention, and is a figure which shows the cross-sectional shape model which modeled the cross-sectional shape of the silicon oxide film. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 4th modification of the 3rd Embodiment of this invention. It is a flowchart for demonstrating the procedure of each step of the pattern shape inspection method which concerns on the 5th modification of the 3rd Embodiment of this invention.

Explanation of symbols

11 substrate 12 to be etched layer 13 organic film 14 a photoresist film 14a, 14b resist pattern 15 SiO ₂ film 15a sidewall portion 21 first pattern 22 second pattern 23 third pattern 30,30a~30e sectional shape model 31 substrate Model 32, 32a, 32b Etched layer model 33a, 33b Side wall model 34 First pattern model

W Wafers L1, L2, L3, L4 Line widths S1, S2, S3, S4 Space width D Thickness S
W1, W2, H1, H2, θ1, θ2 Shape parameters D1, W3, H3, H4 Shape parameters WT1, WT2 Thickness

Claims (22)

A pattern shape inspection method for inspecting a cross-sectional shape of a second pattern including a side wall portion covering a side wall of a first pattern periodically formed on a substrate,
A measurement step of entering incident light at a predetermined incident angle on the substrate on which the second pattern is formed, and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected; ,
Using a cross-sectional shape model that models the cross-sectional shape of the second pattern including a shape parameter that determines the cross-sectional shape of the side wall portion, each of the cross-sections corresponding to a plurality of cross-sectional shape models having different shape parameters. A plurality of calculation data consisting of a calculated amplitude ratio spectrum and a phase difference spectrum of reflected light in which the incident light is diffracted and reflected on a model pattern in which a shape model is continuously formed periodically is calculated. A determination step of determining a cross-sectional shape of the second pattern by determining the model pattern so as to most closely match the measurement data of the second pattern and determining the shape parameter corresponding to the model pattern. A pattern shape inspection method comprising:   After the determining step, the magnitude relationship between the determined shape parameter and predetermined upper limit reference value and lower limit reference value of the shape parameter is determined, and when the shape parameter is larger than the upper limit reference value or the lower limit reference value The pattern shape inspection method according to claim 1, further comprising a determination step of outputting an alarm when smaller.   The pattern shape inspection method according to claim 1, wherein the shape parameter is a width and a height of the side wall portion or an inclination angle from an upper surface of the substrate.   In the determining step, the plurality of calculation data are calculated in advance, a database storing the plurality of calculation data calculated in advance is used, and the calculation data stored in the database is the measurement data of the second pattern. The pattern shape inspection method according to any one of claims 1 to 3, wherein the model pattern is determined so as to most closely match. Forming an organic film on the layer to be etched on the substrate;
A first pattern forming step of processing the organic film by photolithography to form a first pattern having a predetermined pitch;
A film forming step of forming a silicon oxide film on the layer to be etched so as to cover a side surface of the first pattern;
An etching step of etching so that the silicon oxide film remains as a sidewall portion of the first pattern;
A second pattern forming step of forming a second pattern composed of the side wall portions remaining by removing the organic film of the first pattern;
A method for manufacturing a semiconductor device, comprising: a pattern shape inspection step for performing the pattern shape inspection method according to claim 1.   6. The method of manufacturing a semiconductor device according to claim 5, wherein the organic film is a BARC film or a photoresist film.   7. The method of manufacturing a semiconductor device according to claim 5, wherein the pattern shape inspection method is performed between the etching step and the second pattern formation step. A first manufacturing process for manufacturing a semiconductor device on the first substrate using the method for manufacturing a semiconductor device according to claim 7;
A method for manufacturing a semiconductor device, comprising: a second manufacturing step for manufacturing a semiconductor device on a second substrate using the method for manufacturing a semiconductor device according to claim 7 after the first manufacturing step;
When determining the magnitude relationship between the shape parameter determined in the pattern shape inspection step included in the first manufacturing step and a predetermined lower limit value of the shape parameter, and when the shape parameter is smaller than the lower limit value Changing the etching time in the etching step included in the second manufacturing step to be shorter than the etching time in the etching step included in the first manufacturing step, and performing the second manufacturing step. A method of manufacturing a semiconductor device. A first side wall portion covering one side wall of the first pattern periodically formed on the substrate; and a second side wall covering the side wall opposite to the one side of the first pattern. A pattern shape inspection method for inspecting a cross-sectional shape of a second pattern including a side wall portion,
A measurement step of entering incident light at a predetermined incident angle on the substrate on which the second pattern is formed, and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light from which the incident light is diffracted and reflected; ,
A first shape parameter that determines a cross-sectional shape of the first side wall portion; and a second shape parameter that corresponds to the first shape parameter and determines the cross-sectional shape of the second side wall portion. A cross-sectional shape model obtained by modeling the cross-sectional shape of the second pattern is used, and each of the cross-sectional shape models has a period corresponding to the first shape parameter or a plurality of cross-sectional shape models having different second shape parameters. A plurality of calculation data consisting of a calculated amplitude ratio spectrum and a phase difference spectrum of reflected light in which the incident light is diffracted and reflected by a model pattern configured continuously, and the calculation data is the second pattern The model pattern is determined so as to most closely match the measurement data of the pattern, and the first shape parameter and the second shape parameter corresponding to the model pattern are determined. By determining the over data, the pattern shape inspection method characterized by comprising a determining step of determining a cross-sectional shape of the second pattern.   After the determining step, a dimensional difference between the determined first shape parameter and the second shape parameter and a predetermined reference value is determined, and the dimensional difference is larger than the reference value. The pattern shape inspection method according to claim 9, further comprising a determination step of outputting an alarm in the case.   The first shape parameter and the second shape parameter are a width and a height of the first side wall portion and the second side wall portion or an inclination angle from the upper surface of the substrate, respectively. The pattern shape inspection method according to claim 9 or 10.   In the determining step, the plurality of calculation data are calculated in advance, a database storing the plurality of calculation data calculated in advance is used, and the calculation data stored in the database is the measurement data of the second pattern. The pattern shape inspection method according to claim 9, wherein the model pattern is determined so as to most closely match. Forming an organic film on the layer to be etched on the substrate;
A first pattern forming step of processing the organic film by photolithography to form a first pattern having a predetermined pitch;
A film forming step of forming a silicon oxide film on the layer to be etched so as to cover a side surface of the first pattern;
An etching step of etching so that the silicon oxide film remains as a sidewall portion of the first pattern;
A second pattern forming step of forming a second pattern composed of the side wall portions remaining by removing the organic film of the first pattern;
A method for manufacturing a semiconductor device, comprising: a pattern shape inspection step for performing the pattern shape inspection method according to claim 9.   14. The method of manufacturing a semiconductor device according to claim 13, wherein the organic film is a BARC film or a photoresist film.   15. The method of manufacturing a semiconductor device according to claim 13, wherein the pattern shape inspection step is performed between the etching step and the second pattern formation step. A pattern shape inspection method for inspecting a cross-sectional shape of a silicon oxide film covering a first pattern periodically formed on a substrate,
A measurement step of entering incident light at a predetermined incident angle on the substrate on which the silicon oxide film is formed and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light that is diffracted and reflected by the incident light;
Using a cross-sectional shape model obtained by modeling the cross-sectional shape of the silicon oxide film including the thickness of the silicon oxide film, each of the cross-sectional shape models is periodically corresponding to the plurality of cross-sectional shape models having different thicknesses. A plurality of calculation data consisting of a calculated amplitude ratio spectrum and a phase difference spectrum of reflected light in which the incident light is diffracted and reflected by the model pattern configured in succession, and the calculation data of the silicon oxide film Determining the model pattern so as to most closely match the measurement data, and determining the cross-sectional shape of the silicon oxide film by determining the thickness corresponding to the model pattern. Pattern shape inspection method.   After the determining step, the magnitude relationship between the determined thickness and a predetermined upper limit reference value and lower limit reference value of the thickness is determined, and when the thickness is greater than the upper limit reference value or from the lower limit reference value The pattern shape inspection method according to claim 16, further comprising a determination step of outputting an alarm when it is small. A pattern shape inspection method for inspecting a cross-sectional shape of a silicon oxide film covering a first pattern periodically formed on a substrate,
A measurement step of entering incident light at a predetermined incident angle on the substrate on which the silicon oxide film is formed and obtaining measurement data including an amplitude ratio spectrum and a phase difference spectrum of reflected light that is diffracted and reflected by the incident light;
A first thickness of the silicon oxide film covering a side wall on one side of the first pattern, and a second thickness of the silicon oxide film covering a side wall opposite to the one side of the first pattern. A cross-sectional shape model obtained by modeling a cross-sectional shape of the silicon oxide film including the thickness of the first oxide layer, and a plurality of cross-sectional shape models different in the first thickness or the second thickness. Calculating a plurality of calculation data composed of a calculated amplitude ratio spectrum and a phase difference spectrum of reflected light in which the incident light is diffracted and reflected in a model pattern in which a cross-sectional shape model is periodically and continuously formed; Determining the model pattern so as to most closely match the measurement data of the silicon oxide film, and determining the first thickness and the second thickness corresponding to the model pattern Pattern shape inspection method characterized by comprising a determining step of determining a cross-sectional shape of the silicon oxide film.   After the determining step, a dimensional difference between the determined first thickness and the second thickness and a predetermined reference value are determined, and when the dimensional difference is larger than the reference value The pattern shape inspection method according to claim 18, further comprising a determination step of outputting an alarm.   In the determining step, the plurality of calculation data are calculated in advance, a database storing the plurality of calculation data calculated in advance is used, and the calculation data stored in the database is the measurement data of the second pattern. The pattern shape inspection method according to any one of claims 16 to 19, wherein the model pattern is determined so as to most closely match. Forming an organic film on the layer to be etched on the substrate;
A first pattern forming step of processing the organic film by photolithography to form a first pattern having a predetermined pitch;
A film forming step of forming a silicon oxide film on the layer to be etched so as to cover a side surface of the first pattern;
After the film forming step, a pattern shape inspection step for performing the pattern shape inspection method according to any one of claims 16 to 20,
An etching step of etching so that the silicon oxide film remains as a sidewall portion of the first pattern;
A method of manufacturing a semiconductor device, comprising: a second pattern forming step of forming a second pattern composed of the side wall portions remaining by removing the organic film of the first pattern.   22. The method of manufacturing a semiconductor device according to claim 21, wherein the organic film is a BARC film or a photoresist film.

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