WO2023079919A1 - Procédé d'évaluation d'épaisseur de film d'un film d'oxyde et procédé de production d'un substrat de silicium avec un film d'oxyde - Google Patents

Procédé d'évaluation d'épaisseur de film d'un film d'oxyde et procédé de production d'un substrat de silicium avec un film d'oxyde Download PDF

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WO2023079919A1
WO2023079919A1 PCT/JP2022/038112 JP2022038112W WO2023079919A1 WO 2023079919 A1 WO2023079919 A1 WO 2023079919A1 JP 2022038112 W JP2022038112 W JP 2022038112W WO 2023079919 A1 WO2023079919 A1 WO 2023079919A1
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oxide film
film thickness
silicon substrate
thickness
film
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Japanese (ja)
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康太 藤井
達夫 阿部
剛 大槻
健作 五十嵐
正彬 大関
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信越半導体株式会社
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Priority to KR1020247014988A priority Critical patent/KR20240095229A/ko
Priority to CN202280073945.9A priority patent/CN118235236A/zh
Publication of WO2023079919A1 publication Critical patent/WO2023079919A1/fr

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    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/20—Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
    • G—PHYSICS
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    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
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    • G01B11/0641—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of polarization
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J4/00—Measuring polarisation of light
    • G01J4/04—Polarimeters using electric detection means
    • H—ELECTRICITY
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02164—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon oxide, e.g. SiO2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
    • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
    • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
    • H01L21/02238—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor silicon in uncombined form, i.e. pure silicon
    • H—ELECTRICITY
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    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H—ELECTRICITY
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31105—Etching inorganic layers
    • H01L21/31111—Etching inorganic layers by chemical means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/10—Measuring as part of the manufacturing process
    • H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B2210/00—Aspects not specifically covered by any group under G01B, e.g. of wheel alignment, caliper-like sensors
    • G01B2210/56—Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth

Definitions

  • the present invention relates to a method for evaluating the thickness of an oxide film and a method for manufacturing a silicon substrate with an oxide film.
  • the main surface is finished by a polishing process. Furthermore, there is a cleaning process to remove abrasives and metal impurities adhered to the surface of the silicon wafer during the polishing process. In this cleaning process, a cleaning method called RCA cleaning is used.
  • This RCA cleaning is a cleaning method that combines SC1 (Standard Cleaning 1) cleaning, SC2 (Standard Cleaning 2) cleaning, and DHF (Diluted Hydrofluoric Acid) cleaning according to the purpose.
  • SC1 cleaning is a cleaning method using an alkaline cleaning solution in which ammonia water and hydrogen peroxide solution are mixed at an arbitrary ratio. This cleaning method utilizes repulsion to remove particles while suppressing redeposition to silicon wafers.
  • SC2 cleaning is a cleaning method for dissolving and removing metal impurities on the surface of a silicon wafer with a cleaning liquid in which hydrochloric acid and hydrogen peroxide are mixed at an arbitrary ratio.
  • DHF cleaning is a cleaning method for removing a natural oxide film on the surface of a silicon wafer with dilute hydrofluoric acid. Furthermore, ozone water cleaning with strong oxidizing power is sometimes used to remove organic matter adhering to the silicon wafer surface and to form a natural oxide film on the silicon wafer surface after DHF cleaning. Surface quality such as particles and surface roughness of silicon wafers after cleaning is important, and these cleanings are combined depending on the purpose.
  • Semiconductor elements such as MOS (Metal Oxide Semiconductor) capacitors and transistors are formed on the surface of a semiconductor silicon wafer.
  • An insulating film such as a gate oxide film formed in these semiconductor elements is used under a high electric field strength, and a silicon oxide film, which is easy to form, is often used as the insulating film.
  • Measurement using an ellipsometer can be cited as a method for evaluating the thickness of the oxide film on the silicon substrate.
  • An ellipsometer obtains a phase difference ( ⁇ delta) and an amplitude ratio ( ⁇ psi) by making polarized light incident on a substrate sample and measuring changes in the polarization state of the incident light and the reflected light.
  • incident light changes its polarization state by being reflected by the silicon oxide film on the outermost surface and the interface between the silicon oxide film and the silicon substrate.
  • ellipsometers There are two types of ellipsometers: a single-wavelength type that uses a laser as a light source and a spectroscopic type that uses a white light source containing multiple wavelength components. In contrast to measurement, the spectroscopic type can measure the delta and psi for each wavelength, and it is known that the spectroscopic type, which has a large amount of information, can be used to accurately evaluate the film thickness.
  • the information obtained by measuring the ellipsometer is the phase difference and amplitude ratio, and the film thickness cannot be obtained directly.
  • a model corresponding to the substrate sample is created, and the delta and psi obtained theoretically from this model are compared with the delta and psi obtained by ellipsometer measurement.
  • the model is created by setting conditions according to the physical properties of the sample. and so on. For setting each item, a known reference corresponding to the sample, a required dispersion formula showing the wavelength dependence of the dielectric constant and having a plurality of parameters, etc. are usually used.
  • a process of changing the parameters of the dispersion formula and the film thickness of each layer of the model is performed (also called fitting) so that the degree of difference between the two is minimized in the above comparison.
  • the difference between the two is usually obtained by calculation using the method of least squares, and when it is determined that the result obtained by the method of least squares has decreased to some extent by fitting, the value of the parameter of the dispersion formula at that time can be used to determine the thickness of the membrane.
  • the film thickness can be obtained by obtaining the refractive index and the extinction coefficient and specifying the film thickness at that time as the film thickness of the sample. Modeling, fitting, etc. are generally performed manually or automatically based on a required program using a computer.
  • the concept of effective medium approximation may be used (for example, Patent Document 1, etc.).
  • This method is a method of improving the calculation result of the least-squares method by defining roughness and voids as one plane layer.
  • the effective medium approximation is applied not only to the case where roughness exists on the film surface of the sample, but also to the interface layer where roughness exists at the interface between the substrate and the film or between the film layers.
  • the effective medium approximation is sometimes used to lower the value of the refractive index as an analytical technique, regardless of the presence of roughness.
  • the use of the effective medium approximation changes the calculation result of the least squares method, and as a result, the value of the film thickness also changes. It is necessary to judge from
  • Patent Document 2 describes that the film thickness of a native oxide film on a silicon wafer obtained with an ellipsometer changes depending on the surface roughness. Specifically, it discloses a method of quantitatively evaluating the surface roughness from the correlation between the roughness and the film thickness of the native oxide film. Also, an atomic force microscope (AFM) is known as a method for evaluating surface roughness on a silicon substrate. As an index of roughness, an arithmetic average height such as Ra value or Sa value is often used. Ra is the arithmetic average height in the reference length and is a two-dimensional roughness index, and Sa is a parameter obtained by extending Ra to a surface and is a three-dimensional roughness index.
  • AFM atomic force microscope
  • a method of evaluating roughness it is also possible to perform conversion to the spatial frequency domain by spectrum analysis.
  • This method can extract a specific wavelength component from the measured surface profile, for example, a specific spatial wavelength and a parameter related to the amplitude intensity at that wavelength, such as PSD (Power Spectrum Density). be done.
  • PSD Power Spectrum Density
  • a haze value obtained by a particle counter can be used as an index of roughness. Haze is expressed as so-called haze, and is widely used as an index of silicon surface roughness. A high haze level indicates that the surface of the wafer is rough.
  • a dense silicon oxide film with high insulating properties is produced by thermally oxidizing a silicon wafer. is often processed on silicon wafers on which a native oxide film is formed. At this time, it is known that the thickness of the thermal oxide film is affected by the film quality (film thickness and structure) of the natural oxide film before thermal oxidation (Patent Document 3).
  • the thermal oxide film is desired to be thin, the natural oxide film should also be thin, and if the thermal oxide film is to be thick, the natural oxide film should also be thick. Therefore, in recent years, it is especially demanded to control the thickness of the native oxide film within a certain range with good reproducibility.
  • Patent Document 3 describes the relationship between silicon wafers cleaned under various conditions and oxide film thickness after thermal oxidation. Specifically, when the concentration of NH 4 OH in the SC1 cleaning solution is increased, the amount of OH groups contained in the natural oxide film increases and the film thickness after thermal oxidation increases. A method is disclosed for controlling the film thickness after thermal oxidation by using the correlation with the film thickness after thermal oxidation.
  • the surface roughness of the substrate is formed by polishing and subsequent cleaning.
  • SC1 cleaning, hydrofluoric acid cleaning, and ozone water cleaning are used for cleaning substrates after polishing, and it is known that SC1 cleaning, which has etching action, mainly roughens the surface in the cleaning process.
  • Patent Document 3 describes the surface roughness Ra after SC1 cleaning and ozone water cleaning, and its value is about 0.06 to 0.12. Such an Ra value is the roughness value of silicon substrates used in recent years.
  • Patent Document 2 discloses that the surface roughness of the substrate affects the film thickness of the native oxide measured by an ellipsometer. ⁇ 2.05 nm, which is very high compared with the surface roughness Ra value of 0.06 to 0.12 nm described above.
  • the thickness of a natural oxide film is about 1 nm
  • the film thickness of the natural oxide film is 0.097 nm and the Ra value is 1.23 nm.
  • the film thickness of the natural oxide film is 1.586 nm, and the film thickness of the natural oxide film is 3.313 nm when the Ra value is 2.05 nm.
  • the surface roughness and film thickness of the native oxide film described in Patent Document 2 are significantly different from the surface roughness and film thickness of silicon substrates used in recent years.
  • Patent Document 3 focusing on the AFM Ra value and the thermal oxide film thickness obtained by the spectroscopic ellipsometry when the NH 4 OH concentration in SC1 cleaning is varied, which are described in Patent Document 3, it can be seen that the NH 4 OH concentration is The higher the level, the higher the AFM Ra value, and the tendency is obtained that the thermal oxide film thickness also becomes thicker (Fig. 9 of Patent Document 3).
  • the composition (film quality) of a natural oxide film (chemical oxide film) formed in a cleaning process for example, the OH group measured by the ATR (Attenuated Total Reflectance)-FT (Fourier Transform)-IR (Infrared Spectroscopy) method. It is disclosed that the amount of is correlated with the thickness of the thermal oxide film, and it is stated that the higher the NH 4 OH concentration, the thicker the thermal oxide film because the amount of OH groups increases.
  • the surface roughness of the substrate formed in the manufacturing process of the silicon substrate such as an Ra value of 0.06 to 0.12 nm, is one of the factors affecting the oxide film thickness, natural oxide film and In terms of controlling the film thickness of the thermal oxide film, it can be considered as an important quality like the structure (film quality) of the above-described natural oxide film.
  • the present invention has been made to solve the above-mentioned problems, and the film thickness value of the silicon substrate to be evaluated measured by an ellipsometer is different from the surface roughness of the silicon substrate formed in the manufacturing process of the silicon substrate.
  • the present invention has been made to achieve the above objects, and provides a method for evaluating an oxide film on a silicon substrate having a surface roughness Sa value of 0.5 nm or less as measured by an atomic force microscope. and a reference silicon substrate having an average value of power spectral density of 0.1 nm 3 or less at a spatial frequency of 60 to 90 / ⁇ m on the substrate surface.
  • a first film thickness measuring step of measuring the film thickness of the oxide film on the silicon substrate to be evaluated by an ellipsometer; and removing the oxide film by completely removing the oxide film on the silicon substrate to be evaluated and the reference silicon substrate.
  • the oxide film can be evaluated by removing the oxide film by cleaning with hydrofluoric acid.
  • hydrofluoric acid can etch only the natural oxide film on the silicon substrate, it can stably and completely remove only the natural oxide film, and the surface roughness does not change significantly before and after hydrofluoric acid cleaning, so the effect of surface roughness can be evaluated. is particularly effective for
  • an oxide film thickness evaluation method can be used in which an oxide film is formed by cleaning with ozone water or cleaning with hydrogen peroxide water.
  • Ozone water and hydrogen peroxide water have a strong oxidizing action and can stably form a natural oxide film of about 1 nm. can.
  • the oxide film thickness evaluation method can be such that the thickness of the oxide film to be evaluated on the silicon substrate to be evaluated is set to 25 nm or less.
  • the film thickness is 25 nm or less, the influence of the surface roughness of the silicon substrate becomes more pronounced. Therefore, in the present invention, evaluation can be performed with higher accuracy when the film thickness is thinner.
  • the film thickness influencing factor in the film thickness of the oxide film includes the surface roughness of the silicon substrate to be evaluated, and in the film thickness evaluation step, the silicon substrate to be evaluated obtained in the second film thickness measurement step.
  • the differential film thickness obtained by subtracting the film thickness of the oxide film on the reference silicon substrate obtained in the second film thickness measurement step from the film thickness of the upper oxide film is 0.02 nm or more and 0.20 nm or less
  • Oxide film determined to include the thickness of the oxide film caused by the surface roughness of the silicon substrate to be evaluated in the thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measuring step. can be used as a film thickness evaluation method.
  • the surface of the silicon substrate to be evaluated is obtained by subtracting the difference film thickness from the film thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measuring step. It is possible to provide an oxide film thickness evaluation method for evaluating the thickness of an oxide film excluding the influence of roughness.
  • the surface roughness can be a film thickness evaluation method of an oxide film having a roughness component with a spatial frequency of 60 to 90/ ⁇ m.
  • the surface roughness can be used as a film thickness evaluation method of an oxide film, which is a roughness component formed by SC1 cleaning.
  • the film thickness evaluation method according to the present invention can more accurately evaluate the influence of surface roughness caused by a specific cleaning process. This is because roughness with a spatial frequency of 60 to 90/ ⁇ m is formed especially by SC1 cleaning.
  • cleaning conditions and/or oxidation conditions before forming the oxide film on the silicon substrate are set based on the film thickness attributed to the film thickness influencing factor evaluated by the above oxide film thickness evaluation method, and the cleaning conditions and/or oxidation conditions are set.
  • the silicon substrate with an oxide film may be manufactured by washing the silicon substrate and forming an oxide film on the silicon substrate using oxidizing conditions.
  • the oxide film thickness evaluation method of the present invention it is possible to quickly and extremely easily determine whether or not the oxide film thickness value measured by the ellipsometer is affected by the surface roughness of the substrate. can judge.
  • the film thickness value of the silicon substrate to be evaluated measured by the ellipsometer is the same as the surface roughness of the silicon substrate formed in the manufacturing process of the silicon substrate. It is possible to determine whether or not the film thickness value includes the influence of a conventionally unknown film thickness influencing factor, such as thickness, and to evaluate the film thickness caused by the film thickness influencing factor with high accuracy. Further, by calculating the film thickness value due to the surface roughness and the like, it is possible to analyze the natural oxide film and the film thickness after thermal oxidation in more detail. By utilizing this analysis result, the oxide film thickness on the silicon substrate can be accurately controlled.
  • 1 is a flow chart showing an example of a film thickness evaluation method of an oxide film on a silicon substrate according to the present invention
  • 4 shows a flowchart relating to investigation of the relationship between the surface roughness of the silicon substrate and the oxide film thickness.
  • 3 is a graph showing the relationship between the surface roughness (haze) of a silicon substrate subjected to the roughening treatment of FIG. 2 by CMP and SC1 cleaning, and the thickness of a native oxide film and a 5 nm oxide film.
  • 3 is a graph showing the relationship between the surface roughness (haze) of a silicon substrate subjected to the roughening treatment of FIG. 2 by single wafer cleaning and the thickness of a native oxide film and a 5 nm oxide film.
  • the present inventors have found that it is possible to judge whether or not the film thickness value includes the influence, and to evaluate the film thickness caused by the film thickness influencing factor with high accuracy, thus completing the present invention.
  • the present inventors have also provided a method for evaluating the thickness of an oxide film formed on a silicon substrate, which includes surface roughness of the silicon substrate as a film thickness influencing factor in the thickness of the oxide film, and When the average value of the power spectrum density at the surface spatial frequency of 60 to 90/ ⁇ m is 0.15 nm 3 or more, the thickness of the oxide film formed on the silicon substrate is the thickness influencing factor.
  • the oxide film thickness evaluation method that determines that the oxide film thickness due to the surface roughness of the silicon substrate is included, the oxide film thickness value measured by the ellipsometer can be quickly and extremely easily measured on the substrate surface. The inventors have found that it is possible to determine whether or not the surface is affected by the roughness of the surface, thus completing the present invention.
  • the present inventors have conducted extensive studies on factors affecting film thickness in oxide film formation.
  • the roughness formed in the wafer manufacturing process specifically the roughness formed in the polishing process and the cleaning process, and the film quality of the oxide film can be measured with an ellipsometer. It was found that the thickness is affected.
  • the surface roughness of the substrate it was found that the thickness of the oxide film increases when the average value of the power spectrum density (intensity) in a specific frequency band exceeds a predetermined value.
  • FIG. 2 is the survey flow chart.
  • a plurality of levels of silicon substrates were prepared by subjecting the prepared silicon substrates to roughening treatment for forming roughness by changing CMP processing conditions and SC1 cleaning conditions.
  • a natural oxide film was formed by cleaning with ozone water.
  • the oxide film formed by the roughening treatment was completely removed by cleaning with hydrofluoric acid, and the oxide film was formed by the subsequent cleaning with ozone water. is formed.
  • some of the silicon substrates were thermally oxidized with a target film thickness of 5 nm, and the film thickness of the natural oxide film and the formed oxide film with a target film thickness of 5 nm were evaluated by spectroscopic ellipsometry.
  • FIG. 3 is a graph showing the relationship between the surface roughness (Haze) of a silicon substrate subjected to the roughening treatment of FIG. .
  • the film thickness of the natural oxide film and the oxide film aimed at 5 nm were the same even when the haze value exceeded 10 ppm. Both of the oxide films aimed at 5 nm tended to be thicker. Since the oxide film was formed under the same conditions, it was assumed that the film thickness would be similar to that of the CMP level, but not the SC1 cleaning level.
  • FIG. 4 shows the surface roughness (Haze) of the silicon substrate obtained by performing the roughening treatment of FIG. indicates a relationship with Further, hydrofluoric acid cleaning and ozone water cleaning after the roughening treatment were also performed by a single wafer method instead of a batch method. In this case, since the method of forming the oxide film is different from the ozone water cleaning of the batch method, it is not possible to compare the film thickness of the above-mentioned SC1 and CMP levels with the film thickness of the single wafer cleaning level. The influence of Haze can be discussed.
  • the film thickness of the natural oxide film and the oxide film aiming at 5 nm were the same at the single-wafer cleaning level as with the CMP level, even if the haze changed.
  • the roughness formed by CMP and single wafer cleaning does not affect the thickness of the oxide film, and the surface roughness of the substrate formed by SC1 cleaning increases the thickness of the oxide film. It was newly found that
  • FIG. 5 shows the results of the film thickness and haze value of the native oxide film after completely removing the oxide film by acid cleaning and performing ozone water cleaning. Ref.
  • the film thickness of the natural oxide film was 1.207 nm without the cleaning time (0 min), 1.258 nm with the cleaning time of 3 min, 1.258 nm with the cleaning time of 6 min, and 1.261 nm with the cleaning time of 12 min.
  • the difference between the average film thickness of 1.259 nm for cleaning times of 3, 6, and 12 minutes and the film thickness of 1.207 nm without cleaning (cleaning time of 0 min) is 0.052 nm.
  • the amount of thickening is considered to be about 0.052 nm. Haze tended to increase as the cleaning time was longer. It is conceivable that the reason that the film thicknesses of 3, 6 and 12 min are the same is that the roughness component involved in the film thickness (thickening) is the same.
  • FIG. 6 shows the AFM measurement results and PSD curves of each sample.
  • CMP-1 the lowest level
  • CMP-2 the highest level with the haze value in FIG. 3 were evaluated.
  • CMP-2 the power spectral density (intensity) in the low frequency band (1 to 10/ ⁇ m) was very high, and mainly the roughness on the low frequency side was dominant.
  • the AFM image was also obtained as an image like a large undulation, which agreed with each other. Since the roughness formed by CMP does not affect the oxide film thickness as described above, it can be said that the low-frequency component does not affect the oxide film thickness.
  • single-wafer cleaning level As for single-wafer washing levels, the lowest haze value (single-wafer washing-1) and the highest haze value (single-wafer washing-2) in FIG. 4 were evaluated.
  • the power spectral density (intensity) of the single-wafer cleaning level was intermediate between CMP and SC1 cleaning in the high frequency band (10 to 100/ ⁇ m).
  • the SC1 cleaning at -80°C/3 min has more dominant roughness in the high frequency band.
  • the three levels of SC1 cleaning shown 60° C./3 min, 80° C./3 min, 80° C./12 min
  • the spatial frequency band of 60 to 90/ the power spectral densities (intensities) in the ⁇ m range are comparable for all three levels and higher than single wafer cleaning-2. Therefore, it was newly clarified that the roughness component in the range of 60 to 90/ ⁇ m is the roughness component that affects the film thickness of the native oxide film and the 5 nm oxide film.
  • the power spectral density (intensity) at a spatial frequency band of 50/ ⁇ m or less is within the three levels of SC1 cleaning.
  • 80°C/12min > 80°C/3min > 60°C/3min It becomes the magnitude relationship, and the magnitude relationship of the Sa value, 80°C/12min > 80°C/3min > 60°C/3min
  • the Sa value in this case is dominated by the roughness information on the low frequency side where the intensity is high. This is considered to be the cause of the difference in the film thickness of the oxide film despite the fact that the thickness is 0.108 nm.
  • the oxide film becomes thick when the average value of the power spectral density (intensity), which is the roughness component in the spatial frequency band of 60 to 90/ ⁇ m, is greater than or equal to the threshold.
  • the average value of the power spectral density (intensity) in the range of 60 to 90 / ⁇ m for the three levels of SC1 cleaning is calculated, it is 0.16 nm 3 for SC1 cleaning ⁇ 60° C./3 min, and 0 for SC1 cleaning ⁇ 80° C./3 min. 0.18 nm 3 and 0.17 nm 3 after SC1 washing at ⁇ 80° C./12 min.
  • the average value of single-wafer cleaning-2, in which the oxide film was not thickened was 0.11 nm 3 . Therefore, an average power spectral density (intensity) of 0.15 nm 3 from 60 to 90/ ⁇ m is considered a threshold, and a silicon on silicon substrate with an average power spectral density (intensity) of 0.15 nm 3 or higher is present. It can be determined that the thickness of the oxide film is affected by the surface roughness of the substrate and includes the thickness resulting from the surface roughness of the substrate.
  • the factors affecting the film thickness of the natural oxide film and the thermal oxide film include, for example, the structure of the natural oxide film (chemical oxide film) described in Patent Document 3 and the surface roughness of the silicon substrate described above. There are two. Therefore, it is considered that the thickness of the natural oxide film and the thermal oxide film can be controlled by adjusting the structure of the natural oxide film (chemical oxide film) and the surface roughness of the substrate. Further, when it is desired to change the cleaning conditions to thicken or thin the natural oxide film and the thermal oxide film, the film thickness of the silicon substrate after cleaning is affected by either the structure of the natural oxide film or the surface roughness of the substrate. If it is possible to analyze whether it is receiving more strongly, it will be useful knowledge in determining washing conditions.
  • the oxide film thickness evaluation method according to the present invention is very effective in such a case, and an example showing the effectiveness will be specifically described below.
  • FIG. 7A an example in which the SC1 cleaning conditions are varied to control the thickness of the oxide film is shown.
  • a plurality of substrates were processed for each level.
  • half of the wafers of each level were washed with hydrofluoric acid to remove the native oxide film, and then washed with ozone water to form an oxide film under the same conditions.
  • the film thickness of the native oxide film was evaluated by spectroscopic ellipsometry.
  • FIG. 7B shows after SC1 cleaning ( ⁇ ), the higher the cleaning temperature, the thicker the film thickness.
  • the factor of increasing the film thickness after SC1 cleaning ( ⁇ ) as the cleaning temperature increases will be analyzed in more detail.
  • the film thickness was 1.207 nm without SC1 cleaning, 1.206 nm at cleaning temperature of 45°C, 1.258 nm at cleaning temperature of 60°C, and 1.258 nm at cleaning temperature of 80°C. .
  • 1.207 nm without SC1 cleaning and 1.206 nm with cleaning temperature of 45° C. can be interpreted as equivalent film thickness.
  • the cleaning temperatures of 60 and 80° C. it can be interpreted that the film thickness is increased due to the surface roughness. Calculating the amount of film thickness increase due to surface roughness, the difference between 1.258 nm at a cleaning temperature of 60° C.
  • 1.207 nm without SC1 cleaning is 0.051 nm, and at a cleaning temperature of 80° C., the difference is 1.258 nm with SC1 cleaning.
  • the difference from 1.207 nm without the film was 0.051 nm. This 0.051 nm is the film thickness increase due to roughness.
  • the film thickness obtained by subtracting the film thickness increase of 0.051 nm due to the surface roughness from the film thickness at the cleaning temperature of 60° C. and 80° C. after SC1 cleaning ( ⁇ ) is the film thickness excluding the influence of the surface roughness ( ⁇ ).
  • a washing temperature of 45° C. has no effect on roughness, so there is no need to consider it.
  • the oxide film structure is the only factor influencing film thickness, and variations in film thickness are further reduced during manufacturing. can do.
  • the method for evaluating the film thickness of an oxide film on a silicon substrate which takes into consideration the surface roughness of the substrate, is very useful.
  • FIG. 1 is a flow chart showing an example of a method for evaluating the film thickness of an oxide film on a silicon substrate according to the present invention.
  • a method for evaluating a film thickness of an oxide film according to a first embodiment of the present invention is a method for evaluating an oxide film on a silicon substrate having a surface roughness Sa value of 0.5 nm or less as measured by an atomic force microscope. Prepare a silicon substrate to be evaluated on which an oxide film to be evaluated is formed, and a reference silicon substrate having an average power spectral density of 0.1 nm 3 or less at a spatial frequency of 60 to 90/ ⁇ m on the surface of the substrate.
  • a substrate preparation step a first film thickness measurement step of measuring the film thickness of the oxide film on the silicon substrate to be evaluated with an ellipsometer, and an oxide film removal to completely remove the oxide film on the silicon substrate to be evaluated and the reference silicon substrate.
  • an oxide film forming step of forming an oxide film under the same conditions on the silicon substrate to be evaluated and the reference silicon substrate from which the oxide film has been removed; and an oxide film on the silicon substrate to be evaluated after the oxide film forming step.
  • a second film thickness measurement step of measuring the film thickness of the oxide film on the reference silicon substrate with an ellipsometer, and the film thickness of the oxide film on the silicon substrate to be evaluated and the reference silicon substrate obtained in the second film thickness measurement step a film thickness evaluation step of evaluating the film thickness attributed to film thickness influencing factors in the entire film thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measurement step, based on the film thickness of the above oxide film; It is a film thickness evaluation method of an oxide film comprising. Each step will be described in detail below.
  • a silicon substrate to be evaluated and a silicon substrate serving as a reference are prepared. Both have no restrictions on conductivity type, diameter, or sample shape. There are no restrictions on the type of silicon oxide film on the silicon substrate to be evaluated, and there are, for example, natural oxide films, thermal oxide films, and CVD oxide films.
  • the thickness of the oxide film to be evaluated on the silicon substrate to be evaluated is not particularly limited, it is preferably 25 nm or less. When the film thickness is 25 nm or less, the influence of the surface roughness of the silicon substrate becomes more pronounced. Therefore, in the present invention, evaluation can be performed with higher accuracy when the film thickness is thinner.
  • the lower limit of the film thickness of the oxide film to be evaluated on the silicon substrate to be evaluated is not particularly limited as long as it can be measured, but it can be set to 0.5 nm or more.
  • the surface roughness of the silicon substrate to be evaluated must be 0.5 nm or less in Sa value.
  • the reason for this is that when the Sa value is larger than 0.5 nm, the film thickness value of the natural oxide film greatly deviates from 1 nm as in Patent Document 2.
  • the oxide film thickness calculated by spectroscopic ellipsometry deviates greatly from about 1 nm, so the Sa value must be 0.5 nm or less.
  • CMP single-sided polishing
  • DSP double-sided polishing
  • the Sa value of the front surface of a silicon wafer after CMP is 0.1 nm or less
  • the Sa value of the back surface (DSP surface) is about 0.2 to 0.4 nm. A surface roughness with an Sa value exceeding 0.5 nm is not formed.
  • a wafer that has undergone CMP processing at least after DSP processing can be used as the silicon substrate to be evaluated according to the present invention.
  • the present invention can be applied to a silicon substrate to be evaluated having a surface roughness of 0.5 nm or less in Sa value.
  • the lower limit of the surface roughness of the silicon substrate to be evaluated is Sa value of 0.0 nm or more, but may be 0.01 nm or more.
  • the reference silicon substrate must have an Sa value of 0.5 nm or less and an average power spectrum density (intensity) of 0.1 nm 3 or less in the spatial frequency band of 60 to 90/ ⁇ m. If the average value of the power spectral density (intensity) in the spatial frequency band range of 60 to 90 / ⁇ m is greater than 0.1 nm 3 as a reference silicon substrate, the thickness of the oxide film due to the surface roughness is cut off. is difficult. As described above, since the roughness component of 60 to 90/ ⁇ m is formed by SC1 cleaning, not by CMP or single-wafer cleaning, it is necessary to limit the cleaning conditions after polishing when preparing the reference silicon substrate. be.
  • the power spectrum density ( intensity) can be 0.1 nm3 or less.
  • the cleaning temperature is set to 45° C. or less, so that the power spectrum density (intensity) can be 0.1 nm3 or less.
  • Cleaning may be performed by combining hydrofluoric acid, ozone water cleaning, and SC1.
  • a reference silicon substrate can be prepared by such a flow.
  • the average value of the power spectral density (intensity) in the range of 60 to 90/ ⁇ m is 0.1 nm 3 or less.
  • the lower limit of the average power spectral density (intensity) in the spatial frequency band of 60 to 90/ ⁇ m is 0.0 nm 3 or more, but it can be 0.01 nm 3 or more.
  • the oxide film thickness of the silicon substrate to be evaluated is measured with an ellipsometer.
  • an ellipsometer As described above, there are two types of ellipsometers: the single-wavelength type, which uses a laser as a light source, and the spectroscopic type, which uses a white light source containing multiple wavelength components. Although there are no restrictions on the light source, it is more preferable to use a spectroscopic type that can accurately evaluate the film thickness and has a large amount of information.
  • the measuring method of an ellipsometer can be performed by a well-known method. In order to obtain the film thickness, it is necessary to create a model corresponding to the substrate sample.
  • This model is created by setting conditions according to the physical properties of the sample.
  • the film thickness obtained by the first film thickness measurement may be affected by the surface roughness of the substrate described above. Therefore, a method described later is used to verify and determine whether or not the film thickness caused by the surface roughness is included.
  • oxide film removal step Next, the influence of the surface roughness of the silicon substrate is investigated. As shown in S3 of FIG. 1, the oxide films of the silicon substrate to be evaluated and the reference silicon substrate are completely removed.
  • the removal method is not particularly limited, but cleaning with hydrofluoric acid is more preferable. Since hydrofluoric acid etches oxide films but not Si, it can easily and stably completely remove only native oxide films. , especially for evaluating the effect of surface roughness.
  • an oxide film exists on the surface, it becomes a hydrophilic surface, so it can be determined whether the oxide film has been removed from the surface state after cleaning.
  • An example of conditions is, for example, a hydrofluoric acid concentration of 0.3 to 5.0 wt %, a temperature of 10 to 30° C., and a washing time of 60 to 360 seconds.
  • oxide film forming step Next, as shown in S4 of FIG. 1, an oxide film is formed under the same conditions on the silicon substrate to be evaluated and the reference silicon substrate from which the oxide film has been completely removed.
  • the method for forming the oxide film is not particularly limited, but it is more preferable to oxidize the substrate surface with ozone water or hydrogen peroxide water. Ozone water and hydrogen peroxide water have a strong oxidizing action and can easily and stably form a natural oxide film of about 1 nm. can be evaluated.
  • the hydrofluoric acid cleaning described above and the ozone water or hydrogen peroxide water cleaning thereafter can be performed in one batch, which saves time and effort. It is more preferable to wash with ozone water, which has a stronger oxidizing action than hydrogen peroxide water and is more stable. This is because it is preferable that the variation in thickness of the oxide film between the silicon substrate to be evaluated and the reference silicon substrate in this process be as small as possible.
  • the film thickness due to the film thickness influencing factor is evaluated for the entire film thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measurement step.
  • the second film thickness measurement the film thickness of the oxide film formed under the same conditions is evaluated. Therefore, if the substrates (each level) are not affected by film thickness influencing factors such as surface roughness, both substrates should have the same film thickness.
  • the film thickness of the silicon substrate to be evaluated becomes thicker than the film thickness of the reference silicon substrate.
  • the thickness of the oxide film on the silicon substrate to be evaluated obtained in the first step includes the thickness of the oxide film caused by the specific surface roughness of the silicon substrate to be evaluated. can be determined.
  • the thickness of the oxide film on the reference silicon substrate obtained in the second film thickness measurement step is calculated from the thickness of the oxide film on the silicon substrate to be evaluated obtained in the second film thickness measurement step.
  • the subtracted difference film thickness is 0.02 nm or more and 0.2 nm or less
  • the thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measurement step is caused by the surface roughness of the silicon substrate to be evaluated. It is preferable to determine that the film thickness of the oxide film obtained by the calculation is included. According to investigations conducted by the present inventors, when the differential film thickness is less than 0.02 nm, variations in ellipsometer measurement may be the cause.
  • the maximum difference was 0.2 nm. It is realistic to By performing the evaluation in this manner, it is possible to accurately determine whether or not the film thickness value obtained by the ellipsometer is particularly affected by the surface roughness.
  • the surface roughness of the silicon substrate to be evaluated is obtained by subtracting the difference film thickness, that is, the film thickness caused by the surface roughness, from the thickness of the oxide film on the silicon substrate to be evaluated obtained in the first film thickness measurement step. It is possible to calculate and evaluate the thickness of the oxide film excluding the influence of thickness. Especially when there are a plurality of levels of silicon substrates to be evaluated, film thickness variation factors between levels as shown in FIG. 7 can be relatively evaluated.
  • the surface roughness in the oxide film thickness evaluation method according to the present invention can be a roughness component with a spatial frequency of 60 to 90/ ⁇ m. Since the roughness component with a spatial frequency of 60 to 90/ ⁇ m exerts a stronger influence on the thickness of the oxide film, the influence of surface roughness can be evaluated with higher accuracy. Further, the surface roughness can be a roughness component formed by SC1 cleaning. This is because the roughness component with a spatial frequency of 60 to 90/ ⁇ m is formed especially by SC1 cleaning, and the influence of surface roughness caused by a specific cleaning process can be evaluated with higher accuracy.
  • Cleaning conditions and/or oxidation conditions before forming an oxide film on a silicon substrate are set based on the film thickness attributed to the film thickness influencing factors evaluated by the oxide film thickness evaluation method according to the present invention, and these cleaning conditions and A method for manufacturing a silicon substrate with an oxide film is provided, wherein the silicon substrate is washed and an oxide film is formed on the silicon substrate using oxidizing conditions to manufacture the silicon substrate with the oxide film.
  • the oxide film thickness evaluation method according to the present invention it is possible to determine the amount of thickening caused by the film thickness influencing factor.
  • a silicon substrate with an oxide film can be manufactured by controlling the thickness with high accuracy.
  • the thickness of the oxide film formed on the silicon substrate is affected by the thickness of silicon, which is a film thickness influencing factor.
  • an oxide film thickness evaluation method for determining that the oxide film thickness due to the surface roughness of the substrate is included. As described above, if the average value of the power spectral density (intensity) in the spatial frequency band of 60 to 90/ ⁇ m is 0.15 nm 3 or more, the thickness of the natural oxide film measured by the ellipsometer will be equal to the surface roughness of the silicon substrate. It includes the film thickness caused by the thickness.
  • the film thickness of an oxide film obtained by an ellipsometer is evaluated by taking into account the effects of film thickness influencing factors such as surface roughness. can be done. Furthermore, it is also possible to distinguish between the surface roughness of the silicon substrate and the structure of the natural oxide film as the cause of the variation in the thickness of the oxide film, so that the thickness of the oxide film on the silicon substrate can be evaluated with higher accuracy than in the past.
  • AFM measurement was performed on a substrate of level 0 with an observation field of view of 1 ⁇ m ⁇ 1 ⁇ m, and a PSD curve was obtained from spectrum analysis of profile data.
  • Sa was 0.0521 nm, which is 0.5 nm or less, and the average value of the power spectral density (intensity) at a spatial frequency of 60 to 90/ ⁇ m was 0.081 nm 3 , which was 0.1 nm 3 or less.
  • Level 0 was taken as the reference silicon substrate.
  • Levels 1 to 6 were used as silicon substrates to be evaluated.
  • a first film thickness measurement of the silicon substrate to be evaluated is then performed as described in J. Am. A. It was performed on a Woollam spectroscopic ellipsometer M-2000V. As a result, level 1 was 1.033 nm, level 2 was 1.109 nm, level 3 was 1.121 nm, level 4 was 1.169 nm, level 5 was 1.114 nm, and level 6 was 1.109 nm
  • 0.5 wt% hydrofluoric acid was used to remove the oxide film from the substrates of 6 levels of evaluation silicon substrates and 1 level of reference silicon substrates at a cleaning temperature of 25°C for a cleaning time of 3 minutes. It was confirmed that the oxide film was completely removed because the surface condition after washing was water-repellent.
  • the seven levels of substrates were washed with ozone water having a concentration of 20 ppm at a washing temperature of 25° C. for a washing time of 3 minutes to form a natural oxide film on the surface under the same conditions.
  • J. A. A total of 7 levels of second film thickness measurements of silicon substrates were performed using a spectroscopic ellipsometer M-2000V manufactured by Woollam. As a result, level 0 is 1.199 nm, level 1 is 1.202 nm, level 2 is 1.248 nm, level 3 is 1.250 nm, level 4 is 1.291 nm, level 5 is 1.206 nm, and level 6 is 1.206 nm. 202 nm.
  • level 1 When calculating the difference film thickness between each level and level 0 in the second film thickness, level 1 is 0.003 nm, level 2 is 0.049 nm, level 3 is 0.051 nm, level 4 is 0.092 nm, level 5 was 0.007 nm, and level 6 was 0.003 nm. Since the differential film thicknesses of Levels 1, 5, and 6 were 0.01 nm or less, it was determined that the first film thicknesses of Levels 1, 5, and 6 did not include the film thickness caused by the surface roughness. Levels 2, 3, and 4 have a differential film thickness of 0.02 nm or more and 0.20 nm or less. determined that
  • the film thickness was calculated by removing the influence of the surface roughness from the first film thickness.
  • Levels 2, 3, and 4 were calculated by subtracting the difference film thickness from the level 0 in the second film thickness from the first film thickness.
  • 1.060 nm obtained by subtracting the difference film thickness of the second film thickness of 0.049 nm from the first film thickness of 1.109 nm is the film thickness of the first film thickness excluding the influence of the surface roughness.
  • the first film thickness is adopted as it is, and the film thickness obtained by removing the influence of surface roughness from the first film thickness is assumed to be the same value as the first film thickness. bottom.
  • the film thickness after removing the influence of surface roughness from the first film thickness is 1.033 nm for level 1, 1.060 nm for level 2, 1.070 nm for level 3, and 1.070 nm for level 4. 077 nm, level 5 was 1.114 nm, and level 6 was 1.109 nm.
  • Table 2 shows the results of analysis of factors that increase the film thickness of levels 2, 3, and 4 with respect to level 1, which has the thinnest first film thickness, among levels 1, 2, 3, and 4.
  • the difference film thickness with respect to level 1 of the second film thickness is the film thickness due to the surface roughness ( ⁇ ), the film thickness excluding the influence of the surface roughness from the first film thickness, the level 2-4
  • the differential film thickness with respect to 1 was taken as the film thickness ( ⁇ ) due to the structure of the natural oxide film.
  • ⁇ is 0.046 nm at level 2, 0.048 nm at level 3, and 0.089 nm at level 4, and ⁇ is 0.027 nm at level 2, 0.037 nm at level 3, and 0.044 nm at level 4. became. Furthermore, when ⁇ / ⁇ was calculated, Level 2 was 1.703, Level 3 was 1.297, and Level 4 was 2.022. Considering this result, it can be considered that the film thickness due to the surface roughness is saturated in Levels 2 and 3 because the values of ⁇ are almost the same in Levels 2 and 3. It was found that the film thickness of level 3 is thicker than that of level 2 in the first measurement because the film thickness of level 3 is thicker due to the structure of the natural oxide film.
  • Level 4 has the highest ⁇ / ⁇ , and this is because the liquid composition is changed from 1:1:10 to 1:1:100, and the film thickness caused by the surface roughness becomes dominant. It is considered to be. In this way, it was possible to analyze in detail the film thickness variation factors when the cleaning conditions were changed.
  • Example 2 the thickness of the thermal oxide film was evaluated.
  • a silicon substrate to be evaluated a silicon substrate which was cleaned by single wafer cleaning or SC1 cleaning after CMP polishing was prepared. Specific conditions are shown in Table 3.
  • the prepared silicon substrate was thermally oxidized aiming at a film thickness of 5 nm. After that, AFM measurement was performed on the substrate of level A with an observation field of view of 1 ⁇ m ⁇ 1 ⁇ m, and a PSD curve was obtained from spectrum analysis of the profile data. As a result, Sa was 0.5 nm or less at 0.011 nm, and the average value of the power spectral density (intensity) at a spatial frequency of 60 to 90 / ⁇ m was 0.094 nm 3 and 0.1 nm 3 or less.
  • the substrate of A was used as a reference silicon substrate, and the substrates of four levels of levels B, C, D, and E were used as silicon substrates to be evaluated.
  • the first film thickness measurement of the silicon substrate to be evaluated was performed by J. A. It was performed on a Woollam spectroscopic ellipsometer M-2000V. As a result, the level B was 5.185 nm, the level C was 5.269 nm, the level D was 5.272 nm, and the level E was 5.318 nm.
  • level A was 1.201 nm
  • level B was 1.201 nm
  • level C was 1.249 nm
  • level D was 1.249 nm
  • level E was 1.285 nm.
  • level B is 0.000 nm
  • level C is 0.048 m
  • level D is 0.048 nm
  • level E was 0.084 nm.
  • the differential film thickness of level B is 0.01 nm or less, it was determined that the first film thickness of level B did not include the film thickness due to the surface roughness. Since the differential film thickness of levels C, D, and E is 0.02 nm or more and 0.20 nm or less, the first film thickness of standards C, D, and E includes the film thickness caused by the surface roughness. I decided.
  • the film thickness was calculated by removing the influence of the surface roughness from the first film thickness.
  • Levels C, D, and E were calculated by subtracting the difference in film thickness from level A in the second film thickness from the first film thickness. Since level B is not affected by roughness, the first film thickness was used as is, and the film thickness obtained by removing the influence of surface roughness from the first film thickness was the same value as the first film thickness.
  • the film thickness after removing the influence of surface roughness from the first film thickness was 5.185 nm for level B, 5.221 nm for level C, 5.224 nm for level D, and 5.224 nm for level E. .234 nm.
  • both the magnitude relationship of the film thickness excluding the influence of the surface roughness from the first film thickness and the magnitude relationship of the first film thickness are Level E > Level D > Level C > Level B became.
  • Levels B, C, D, and E are levels with different SC1 cleaning conditions, so the first film thickness fluctuates due to the effects of both the surface roughness and structure of the native oxide film depending on the cleaning conditions. I figured out what I did.
  • Table 4 shows the results of analysis of factors that increase the film thickness of standards C, D, and E with respect to level B, which has the thinnest first film thickness, among standards B, C, D, and E.
  • the difference film thickness with respect to the level B of the second film thickness is the film thickness caused by the surface roughness ( ⁇ )
  • the film thickness excluding the influence of the surface roughness from the first film thickness is the level C, D, and E.
  • the difference film thickness with respect to the level B was taken as the film thickness ( ⁇ ) due to the structure of the natural oxide film.
  • ⁇ is 0.048 nm at level C, 0.048 nm at level D, and 0.084 nm at level E
  • ⁇ is 0.036 nm at level C, 0.039 nm at level D, and 0.039 nm at level E. 049 nm.
  • level C was 1.333
  • level D was 1.230
  • level E was 1.714. In this way, it was possible to analyze in detail the film thickness variation factors when the cleaning conditions were changed.
  • the film thickness value includes the influence of the film thickness influencing factor such as the wafer surface roughness formed in the silicon wafer manufacturing process, and the film thickness influencing factor
  • the film thickness influencing factor such as the wafer surface roughness formed in the silicon wafer manufacturing process
  • the present invention is not limited to the above embodiments.
  • the above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

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Abstract

La présente invention concerne un procédé d'évaluation d'un film d'oxyde sur un substrat de silicium qui possède une rugosité de surface Sa inférieure ou égale à 0,5 nm telle que déterminée par AFM, le procédé comprenant : une étape de préparation d'un substrat à évaluer, le substrat étant pourvu d'un film d'oxyde, et d'un substrat de référence, la surface du substrat ayant une densité spectrale de puissance moyenne inférieure ou égale à 0,1 nm3 à une fréquence spatiale de 60-90/µm ; une première étape de mesure d'épaisseur de film en vue de mesurer l'épaisseur de film du film d'oxyde sur le substrat à évaluer ; une étape de retrait du film d'oxyde sur le substrat à évaluer et du film d'oxyde sur le substrat de référence ; une étape de formation d'un film d'oxyde sur le substrat à évaluer et sur le substrat de référence dans les mêmes conditions après l'élimination de film d'oxyde décrite ci-dessus ; une seconde étape de mesure d'épaisseur de film en vue de mesurer l'épaisseur de film du film d'oxyde sur le substrat à évaluer et l'épaisseur de film du film d'oxyde sur le substrat de référence ; et une étape d'évaluation de l'épaisseur de film du film d'oxyde sur le substrat à évaluer, l'épaisseur de film étant obtenue dans la première étape de mesure d'épaisseur de film et étant attribuée à un facteur d'influence d'épaisseur de film, sur la base des épaisseurs de film des films d'oxyde sur le substrat à évaluer et le substrat de référence, les épaisseurs de film étant obtenues dans la seconde étape de mesure d'épaisseur de film. Par conséquent, la présente invention concerne un procédé d'évaluation d'épaisseur de film d'un film d'oxyde, le procédé évaluant l'épaisseur de film d'un film d'oxyde attribué à un facteur d'influence d'épaisseur de film à précision élevée.
PCT/JP2022/038112 2021-11-08 2022-10-12 Procédé d'évaluation d'épaisseur de film d'un film d'oxyde et procédé de production d'un substrat de silicium avec un film d'oxyde WO2023079919A1 (fr)

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CN202280073945.9A CN118235236A (zh) 2021-11-08 2022-10-12 氧化膜的膜厚评价方法及带有氧化膜的硅基板的制造方法

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11111674A (ja) * 1997-09-30 1999-04-23 Shin Etsu Handotai Co Ltd シリコンウエーハの表面粗さを改善する方法および表面粗さを改善したシリコンウエーハ
JP2004193534A (ja) * 2002-09-05 2004-07-08 Toshiba Ceramics Co Ltd シリコンウエハの洗浄方法および洗浄されたシリコンウエハ
JP2005109149A (ja) * 2003-09-30 2005-04-21 Toshiba Ceramics Co Ltd 半導体ウエハの製造方法
JP2009267125A (ja) * 2008-04-25 2009-11-12 Shin Etsu Handotai Co Ltd シリコンウェーハの酸化膜形成方法
JP2010050353A (ja) * 2008-08-22 2010-03-04 Shin Etsu Handotai Co Ltd 半導体ウエーハ及び半導体ウエーハの製造方法並びに半導体ウエーハの評価方法
US20190131191A1 (en) * 2017-10-31 2019-05-02 Sk Siltron Co., Ltd. Method for predicting thickness of oxide layer of silicon wafer
JP6791453B1 (ja) * 2020-05-08 2020-11-25 信越半導体株式会社 半導体基板の熱酸化膜形成方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06163662A (ja) 1992-11-17 1994-06-10 Sharp Corp 半導体基板表面ラフネス値の測定方法
JP4435298B2 (ja) 2004-03-30 2010-03-17 株式会社堀場製作所 試料解析方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11111674A (ja) * 1997-09-30 1999-04-23 Shin Etsu Handotai Co Ltd シリコンウエーハの表面粗さを改善する方法および表面粗さを改善したシリコンウエーハ
JP2004193534A (ja) * 2002-09-05 2004-07-08 Toshiba Ceramics Co Ltd シリコンウエハの洗浄方法および洗浄されたシリコンウエハ
JP2005109149A (ja) * 2003-09-30 2005-04-21 Toshiba Ceramics Co Ltd 半導体ウエハの製造方法
JP2009267125A (ja) * 2008-04-25 2009-11-12 Shin Etsu Handotai Co Ltd シリコンウェーハの酸化膜形成方法
JP2010050353A (ja) * 2008-08-22 2010-03-04 Shin Etsu Handotai Co Ltd 半導体ウエーハ及び半導体ウエーハの製造方法並びに半導体ウエーハの評価方法
US20190131191A1 (en) * 2017-10-31 2019-05-02 Sk Siltron Co., Ltd. Method for predicting thickness of oxide layer of silicon wafer
JP6791453B1 (ja) * 2020-05-08 2020-11-25 信越半導体株式会社 半導体基板の熱酸化膜形成方法

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