JP3681523B2 - Optical evaluation apparatus, optical evaluation method, semiconductor device manufacturing apparatus, and semiconductor device manufacturing apparatus management method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an optical evaluation apparatus and an optical evaluation method suitable for in-line characteristic evaluation in a semiconductor device manufacturing process., HalfHow to manage conductor equipment manufacturing equipment and semiconductor equipment manufacturing equipmentTo the lawRelated.
[0002]
[Prior art]
  In recent years, high integration of semiconductor integrated circuits has been greatly advanced, and in a MOS type semiconductor device, transistor elements have been miniaturized and high performance has been achieved. Realization of highly functional MOS devices has become necessary. In order to improve the reliability of the MOS device, it is necessary that each part constituting the MOS device has high reliability.
[0003]
  An important part that affects the reliability of such a MOS device is, for example, the reliability of the contact portion that is affected by the method of forming the contact window. The damage layer of the semiconductor substrate caused by dry etching used to form the contact window is removed by wet etching after dry etching. By measuring the electrical characteristics of a wafer, etc., the depth of the damaged layer generated under the dry etching conditions can be ascertained, or wet etching to remove the damaged layer from the measurement result of the electrical characteristics. Conditions such as time and temperature are set. In this manner, in the conventional method for manufacturing a semiconductor device, control is performed so that the processing conditions during the manufacturing process of the semiconductor device are appropriate based on the electrical characteristics obtained using the monitor wafer.
[0004]
  Further, among the processes for forming each element of the semiconductor device, for example, the impurity introduction technique is an important process for determining the operating characteristics of the semiconductor device. For the introduction of impurities, an ion implantation method, that is, a method in which ions are accelerated by an electric field and the impurity ions are introduced into a semiconductor substrate or an electrode is the mainstream. At this time, the impurity ions are usually accelerated with an energy of several tens of keV and implanted into a semiconductor substrate or the like. However, as a result of the implantation of the impurity ions, a damaged layer having broken crystallinity is generated on the surface layer of the semiconductor substrate or the like, the impurities are not activated as carriers, and the impurity concentration distribution is also desired. It is not in the distribution state. Therefore, heat treatment (annealing) is performed after ion implantation in order to activate impurities, recover damage, and optimize profiles. Conventionally, the annealing process time, temperature, and the like are determined by design (device simulation) and optimization of conditions, and basically, annealing conditions are set based on experience. In particular, the annealing process for recovering the surface defect layer of the semiconductor substrate has been based on experience.
[0005]
  Next, gate insulating films used in MOS devices are rapidly becoming thinner, and it is expected that very thin insulating films of 4 nm or less will be used in the 21st century. In MOS devices having such an extremely thin insulating film, it is said that the characteristics of the insulating film determine the characteristics of the entire MOS device and further the electrical characteristics of the entire semiconductor integrated circuit, and the characteristics of the insulating film are particularly important. Is being viewed.
[0006]
  The characteristics of such a gate insulating film have been conventionally managed by forming a MOS capacitor or a MOS transistor and evaluating the electrical characteristics. The evaluation of the electrical characteristics is performed by taking out the wafer on which the MOS device is mounted from the chamber during or after the manufacture of the MOS device.
[0007]
[Problems to be solved by the invention]
  By the way, with the miniaturization of the MOS device as described above, the above-described conventional evaluation method has the following problems in the above etching process, impurity introduction process, and gate insulating film formation process.
[0008]
  First, the etching process has the following problems. While the planar size (lateral size) of the contact window is reduced, the depth of the contact window must not be reduced, and as a result, the aspect ratio (= depth / lateral size) is increased. In order to form a contact window having such a high aspect ratio, for example, a high vacuum / high density plasma is used in a dry etching process. In the high-vacuum and high-density plasma process, deep contact windows are formed using ions with high energy and directivity. However, unlike the conventional level of defects caused by dry etching with relatively low vacuum and low density plasma due to the impact of high energy ions, the depth of damage layer and damage caused by the semiconductor crystal at the bottom of the contact The degree is getting bigger. Also, when evaluating the damage layer using light in the microwave region (infrared rays or the like), the light itself penetrates from the Si substrate to a depth of 1 μm or more, so that damage to the Si substrate at a level of several tens of nanometers by actual plasma Could not be accurately evaluated. That is, with the miniaturization of LSIs in the future, it has become impossible to give an accurate result to the evaluation of a damage layer that is thinly formed near the surface layer or an extremely miniaturized region.
[0009]
  Therefore, it is difficult to remove the damaged layer reliably or to remove the damaged layer with good control only by using the conventional evaluation method.
[0010]
  Next, there are the following problems in the impurity introduction process and the annealing process. As each element in a semiconductor device is miniaturized and the importance of impurity introduction and profile control in a minute region increases, the setting of annealing conditions based on the above experience often results in an optimum profile. There was no result, and there was a problem that the processing was finished with defects remaining in the semiconductor substrate. In addition, there is an urgent need to shorten the development period of the desired semiconductor device. If the annealing conditions are optimized by the conventional process → analysis → process → analysis procedure, the development efficiency is significantly reduced. End up. Therefore, recently, a process control technique based on an in-situ observation technique of the annealing process has been eagerly desired. In addition, when performing heat treatment using a single-wafer type heat treatment apparatus, unlike the conventional batch type, subtle variations in the amount of heat treatment between wafers have occurred due to variations in the characteristics of the heat treatment apparatus and changes over time. . Furthermore, it has been difficult to accurately grasp the actual dose amount at the time of impurity introduction and the effective impurity concentration introduced into the substrate after the heat treatment.
[0011]
  In the process of forming the gate insulating film, there are the following problems. When managing the characteristics of the gate insulating film by evaluating the electrical characteristics as described above, the process is completed even if any trouble occurs in the insulating film formation process during the manufacture of the MOS device. The defect is found only after the wafer is taken out of the chamber and the electrical characteristics are evaluated. Therefore, until then, a defective gate insulating film is continuously formed, resulting in a decrease in productivity (efficiency).
[0012]
  The first object of the present invention is to provide an optical evaluation apparatus and method capable of reliably grasping in-line the factors affecting the characteristics of the semiconductor device during the manufacturing process as described above and realizing good and uniform characteristics. It is to provide.
[0013]
  The second object of the present invention is to pay attention to the fact that there is a correlation between the optical characteristics of the semiconductor region and the state of the semiconductor region, and inline various processes for the semiconductor device using the evaluation of the optical characteristics. Controlled semiconductor devicesSetIt is to provide a manufacturing apparatus.
[0014]
  A third object of the present invention is to provide a semiconductor device manufacturing apparatus management method for performing maintenance of a chamber of a semiconductor device manufacturing apparatus using a change in evaluation accuracy of optical characteristics.
[0015]
[Means for Solving the Problems]
  In order to achieve the first object, the present invention provides a first claim.To 3Means relating to the first optical evaluation device described in claim 1, and4 to 5Means relating to the second optical evaluation device described in 1.Means for a third optical evaluation device according to claims 6-16;Claim22 to 27And measures relating to the optical evaluation method described in the above.
[0016]
  In order to achieve the second object, the present invention claims18 to 21For manufacturing apparatus of semiconductor device described in 1TheI'm taking it.
[0017]
  In order to achieve the third object, the present invention claims28 to 40The measures regarding the management method of the manufacturing apparatus of the semiconductor device described in 1 are taken.
[0018]
  A first optical evaluation apparatus according to the present invention is an optical evaluation apparatus used when a substrate having a semiconductor region is processed in a chamber, as described in claim 1. For intermittently irradiating the semiconductor region of the semiconductor substrate in the chamber with the first light source that generates the second light source, the second light source that generates the measurement light, and the excitation light generated by the first light source. The first light guide member, the second light guide member for irradiating the semiconductor region with the measurement light generated by the second light source, and the reflectance of the measurement light irradiated on the semiconductor region are detected. And a third light guide member for causing the measurement light reflected from the semiconductor region to enter the reflectance detection unit, and an output from the reflectance detection unit to receive the measurement light reflected from the semiconductor region. When excitation light is irradiated to and excitation light A change calculating means for calculating a value obtained by dividing a difference in reflectance of the measurement light from when not irradiated with the reflectance of the measurement light when not irradiated with the excitation light as a change rate of the reflectance of the measurement light; WithThe first light source and the second light source are configured by a single common light source that generates a broad spectrum light having a wavelength including the wavelengths of the excitation light and the measurement light. A beam splitter that separates the generated broad spectrum light into excitation light and measurement light; and a spectroscopic means that receives the measurement light reflected from the semiconductor region, splits the measurement light, and then sends the measurement light to the reflectance detection means. In addition, the first and second light guiding members are disposed at positions to receive light from the beam splitter.ing.
[0019]
  By using this optical evaluation device, the following effects can be obtained. When excitation light guided by the first light guiding member is irradiated onto the semiconductor region, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region by the second light guide member changes with and without excitation light irradiation, and this rate of change depends on the magnitude of the electric field strength and the measurement. It varies depending on the wavelength of light. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. Therefore, it is possible to control the conditions of the processing performed in the chamber based on the in-line evaluation of the semiconductor region.
[0020]
  In addition, since the light source is unified, the structure of the optical evaluation device is extremely simplified.
[0021]
  According to a second aspect of the present invention, in the first aspect, the second light guide member transmits the measurement light to the surface of the substrate.DrippingIt is preferable that the light is incident from a straight direction.
[0022]
  This allows the measurement light to beDrippingSince it is configured to irradiate from a straight direction, a change in reflectance can be evaluated quickly and accurately for a minute semiconductor region. That is, an optical evaluation apparatus capable of performing optical evaluation in the manufacturing process of a semiconductor device to be miniaturized is obtained.
[0023]
  According to a third aspect of the present invention, in the second aspect, the first light guiding member transmits the excitation light to the surface of the substrate.DrippingIt is preferable that the light is incident from a straight direction.
[0024]
  ThisMeasurement light and excitation light are on the surface of the semiconductor regionDrippingSince the light is irradiated from a straight direction, even when the semiconductor region is extremely narrow, it is possible to perform optical evaluation using the change rate of the reflectance of the measurement light. Therefore, an optical evaluation device particularly suitable for detecting the processing state in the semiconductor region in real time can be obtained.
[0025]
  A second optical evaluation apparatus according to the present invention is an optical evaluation apparatus used when processing a substrate having a semiconductor region in a chamber as described in claim 4, wherein the excitation light A first light source that generates the measurement light, a second light source that generates the measurement light, and an excitation generated by the first light source. A first light guiding member for intermittently irradiating the semiconductor region of the semiconductor substrate in the chamber with a first light guide member for irradiating the semiconductor region with the measurement light generated by the second light source. 2 light guide members, reflectance detection means for detecting the reflectance of the measurement light applied to the semiconductor region, and measurement light reflected from the semiconductor region for entering the reflectance detection means The difference in reflectance of the measurement light between the third light guide member and the output of the reflectance detection means and when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated Change calculation means for calculating a value obtained by dividing the reflectance of the measurement light when the excitation light is not irradiated as a change ratio of the reflectance of the measurement light, and the change calculation means includes the reflectance of the measurement light. Poles in the spectrum of the change rate of Only the change rate of the reflectance of the measurement light at a specific energy value of the measurement light that gives computing.
[0026]
  By using this optical evaluation device, the following effects can be obtained. When excitation light guided by the first light guiding member is irradiated onto the semiconductor region, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region by the second light guide member changes with and without excitation light irradiation, and this rate of change depends on the magnitude of the electric field strength and the measurement. It varies depending on the wavelength of light. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. Therefore, it is possible to control the conditions of the processing performed in the chamber based on the in-line evaluation of the semiconductor region.
[0027]
  AlsoOnly the change in the reflectance of the measurement light having the specific wavelength that is most desirable can be detected. Therefore, optical evaluation without noise and high sensitivity is possible.
[0028]
  Claim5As claimed in4In the above, it is preferable that the specific energy value of the measurement light be any value included in the range of 3.2 to 3.6 eV.
[0029]
  First of the present invention3The optical evaluation device of claim6An optical evaluation apparatus for evaluating electrical characteristics of an insulating film formed on a semiconductor region of a substrate, comprising: a first light source that generates excitation light; and measurement light. A second light source to be generated, a first light guiding member for intermittently irradiating the semiconductor region directly below the insulating film through the insulating film with the excitation light generated by the first light source; A second light guide member for irradiating the semiconductor region with the measurement light generated by the second light source through the insulating film and irradiating the semiconductor region irradiated with the excitation light intermittently; A reflectance detecting means for detecting the reflectance of the measured light, a third light guide member for causing the measuring light reflected from the semiconductor region to enter the reflectance detecting means, and the reflectance detecting means. In response to the output, the semiconductor region is irradiated with excitation light By dividing the difference in the reflectance of the measurement light from when the excitation light is not irradiated by the reflectance of the measurement light when the excitation light is not irradiated, the change rate of the reflectance of the measurement light is obtained. And a change calculating means for calculating, and an evaluating means for evaluating the electrical characteristics of the insulating film based on the change rate of the reflectance of the measurement light.
[0030]
  As a result, information about electrical defects in the insulating film, particularly the gate insulating film, can be obtained. That is, when the semiconductor region is irradiated with excitation light, carriers are excited, and the electric field strength changes with the change in the number of carriers, so that the reflectance of the measurement light in a certain wavelength region from the semiconductor region changes. At that time, if an insulating film is formed on the semiconductor region, a defect site serving as a carrier trap exists in the surface layer of the semiconductor region, so that the change rate of the reflectance of the measurement light is reduced. However, if the number of defects (trap electrons) in the insulating film is large, the amount of increase in the electric field strength in the adjacent semiconductor region increases, and the rate of change in the reflectance of the measurement light increases. Therefore, it is possible to quickly and surely manage the electrical characteristics of the insulating film by determining that the reflectance of the measurement light is outside the predetermined range by the evaluation means as being defective.
[0031]
  Claim7As claimed in6In the spectrum of the change rate of the reflectance of the measurement light.PoleIt can be determined that the non-defective product is determined only when the change ratio of the reflectance of the measurement light at the specific energy value of the measurement light that gives the value is a value corresponding to the appropriate capacitance value of the insulating film.
[0032]
  Claim8As claimed in6, The specific energy value of the measurement light can be any value within the range of 3.2 to 3.6 eV.
[0033]
  Claim7Or8As a result, the optical evaluation is performed at a location where the sensitivity for detecting the difference in the electrical characteristics of the insulating film is the best in the spectrum of the change ratio of the reflectance indicating the characteristic shape.
[0034]
  Claim9As claimed in6 to 8In any one of the above, a spectroscopic unit that receives the measurement light reflected from the semiconductor region, splits the measurement light, and sends the measurement light to the reflectance detection unit can be further provided.
[0035]
  Thereby, since the spectrum of the change ratio of the reflectance of the measurement light is detected, it becomes possible to perform highly accurate optical evaluation based on the information of the entire spectrum shape.
[0036]
  Claim10As claimed in6 to 8In any one of the above, the measurement light reflected from the semiconductor region is received, and only the measurement light in the wavelength range corresponding to the specific energy value of the measurement light is transmitted and sent to the reflectance detection means The filter may be further provided.
[0037]
  Accordingly, since a change in reflectance in a desired wavelength range can be detected without providing a spectroscopic means, the structure of the optical evaluation device is simplified, and rapid optical evaluation is possible.
[0038]
  Claim11As claimed in6In the above, it is preferable that the reflectance detection means detects the reflectance of measurement light in a wavelength range of 600 nm or less.
[0039]
  Claim12As claimed in11In the above, it is more preferable that the reflectance detection means detects the reflectance of measurement light in the wavelength range of 300 to 600 nm.
[0040]
  Claim11Or12By using the fact that the measurement light in the visible light region and the wavelength region below it does not reach a depth of several hundred nm or more in the semiconductor region, the region affected by trapped electrons in the insulating film in the semiconductor region The optical evaluation can be performed based on the change rate of the reflectance only from the above.
[0041]
  Claim13As claimed in6 to 12In any one of the above, the optical evaluation device can be configured using an ellipsometry spectrometer.
[0042]
  This makes it possible to configure an optical evaluation apparatus at low cost by using an ellipsometry spectrometer used for measuring the thickness of a gate oxide film or the like.
[0043]
  Claim14As claimed in6 to 13In any one of them, the optical evaluation device is preferably attached to a chamber used for forming an oxide film of a semiconductor device.
[0044]
  Thereby, the quality of the insulating film can be evaluated without taking out the semiconductor substrate from the manufacturing apparatus, so that the evaluation apparatus is suitable for in-line characteristic evaluation.
[0045]
  Claim15As claimed in6The second light source may be an Xe lamp.
[0046]
  Claim16As claimed in6The first light source may be an Ar ion laser or a He—Ne laser.
[0047]
  Claim17As claimed in6 to 16In any one of the above, it is preferable that the first light guide member is configured to irradiate the excitation light intermittently at a frequency of 1 kHz or less.
[0048]
  Of the present inventionFirstAn apparatus for manufacturing a semiconductor device is claimed18A chamber for storing a substrate having a semiconductor region, a processing means for processing the substrate in the chamber, and a semiconductor of the substrate installed in the chamber First light supply means for irradiating the region intermittently with excitation light, second light supply means for irradiating the semiconductor region with measurement light, and reflection of measurement light irradiated on the semiconductor region The difference in reflectance of the measurement light between the reflectance detection means for detecting the rate and the output of the reflectance detection means when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated Is calculated as a change ratio of the reflectance of the measurement light when the excitation light is not irradiated, and a change calculation means for calculating the change rate of the reflectance of the measurement light. Change calculation means Receiving the output, and a processing control means for controlling the processing conditions on the basis of the change rate of the reflectanceThe processing means performs etching of the semiconductor region by generating plasma in the chamber..
[0049]
  By using this semiconductor device manufacturing apparatus, the following effects can be obtained. When excitation light is irradiated onto the semiconductor region by the first light supply means, carriers are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light supplied by the second light supply means changes with and without the excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the measurement light. It varies depending on the wavelength. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. Then, since the processing conditions performed in the chamber are controlled by the processing control means based on the in-line evaluation of the semiconductor region, a semiconductor device having desired characteristics can be formed with good reproducibility. .
[0050]
  AlsoSince it becomes possible to control the depth of the damaged layer and the degree of damage caused by etching, it becomes possible to smoothly remove the damaged layer later.
[0051]
  According to a second semiconductor device manufacturing apparatus of the present invention, a chamber for storing a substrate having a semiconductor region and a process for processing the substrate in the chamber are provided. Processing means; first light supply means for intermittently irradiating the semiconductor region of the substrate disposed in the chamber with excitation light; and second light for irradiating the semiconductor region with measurement light. A light supply means and a counter for detecting the reflectance of the measurement light irradiated on the semiconductor region; The difference between the reflectance of the measurement light when the excitation light is irradiated to the semiconductor region and the excitation light is not irradiated with the output of the reflectance detection means and the reflectance detection means. Change calculation means for calculating a value obtained by dividing the reflectance of the measurement light when it is not irradiated as a change ratio of the reflectance of the measurement light, and during the progress of the processing by the processing means, the change calculation means Processing control means for receiving the output and controlling the processing conditions based on the reflectance change rate;The processing means performs light dry etching for generating a plasma in the chamber to remove a damaged layer caused by etching of the semiconductor region.
[0052]
  By using this semiconductor device manufacturing apparatus, the following effects can be obtained. When excitation light is irradiated onto the semiconductor region by the first light supply means, carriers are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light supplied by the second light supply means changes with and without the excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the measurement light. It varies depending on the wavelength. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. Then, since the processing conditions performed in the chamber are controlled by the processing control means based on the in-line evaluation of the semiconductor region, a semiconductor device having desired characteristics can be formed with good reproducibility. .
[0053]
  AlsoIt is possible to perform light dry etching for removing the damaged layer after grasping the depth of the damaged layer and the degree of damage caused by the etching.
[0054]
  According to a third aspect of the present invention, there is provided a manufacturing apparatus for a semiconductor device, comprising: a chamber for storing a substrate having a semiconductor region; and a processing process for the substrate in the chamber. Processing means; first light supply means for intermittently irradiating the semiconductor region of the substrate disposed in the chamber with excitation light; and second light for irradiating the semiconductor region with measurement light. Light supply means, reflectance detection means for detecting the reflectance of the measurement light irradiated on the semiconductor region, and output from the reflectance detection means, and excitation when the semiconductor region is irradiated with excitation light Change calculation that calculates the difference between the reflectance of the measurement light and the measurement light reflectance when the excitation light is not irradiated as the change rate of the measurement light reflectance. Means and the above processing During the course of processing by means receives the output of the change computing means, and a processing control means for controlling the processing conditions on the basis of the change rate of the reflectance,The processing means forms a thin insulating film on the semiconductor region.
[0055]
  By using this semiconductor device manufacturing apparatus, the following effects can be obtained. When excitation light is irradiated onto the semiconductor region by the first light supply means, carriers are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light supplied by the second light supply means changes with and without the excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the measurement light. It varies depending on the wavelength. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. The processing control means controls the processing conditions performed in the chamber based on the in-line evaluation of the semiconductor region, so that a semiconductor device having desired characteristics can be formed with good reproducibility. It will be.
[0056]
  AlsoIt is possible to form an insulating film having desired characteristics, for example, a gate oxide film.
[0057]
  According to a fourth aspect of the present invention, there is provided a manufacturing apparatus for a semiconductor device, comprising: a chamber for storing a substrate having a semiconductor region; and a processing for processing the substrate in the chamber. Processing means; first light supply means for intermittently irradiating the semiconductor region of the substrate disposed in the chamber with excitation light; and second light for irradiating the semiconductor region with measurement light. Light supply means, reflectance detection means for detecting the reflectance of the measurement light irradiated on the semiconductor region, and output from the reflectance detection means, and excitation when the semiconductor region is irradiated with excitation light Change calculation that calculates the difference between the reflectance of the measurement light and the measurement light reflectance when the excitation light is not irradiated as the change rate of the measurement light reflectance. Means and the above processing During the course of processing by means receives the output of the change computing means, and a processing control means for controlling the processing conditions on the basis of the change rate of the reflectance,A thin insulating film is formed on the semiconductor region, and the processing means performs dry etching for removing the insulating film on the semiconductor region.
[0058]
  By using this semiconductor device manufacturing apparatus, the following effects can be obtained. When excitation light is irradiated onto the semiconductor region by the first light supply means, carriers are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light supplied by the second light supply means changes with and without the excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the measurement light. It varies depending on the wavelength. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, since the rate of change in reflectivity with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, the change calculation means uses the detection value of the reflectivity detection means to detect the semiconductor region. When the change rate of the reflectivity of the measurement light at is calculated, the change rate of the reflectivity reflects the crystal state of the semiconductor region and the like. Then, since the processing conditions performed in the chamber are controlled by the processing control means based on the in-line evaluation of the semiconductor region, a semiconductor device having desired characteristics can be formed with good reproducibility. .
[0059]
  AlsoThe progress of the removal of the insulating film can be controlled by in-line optical evaluation by utilizing the fact that the change rate of the reflectance of the measurement light from the semiconductor region is affected by the thickness of the insulating film.
[0060]
  Of the present inventionFirstAn optical evaluation method of a semiconductor device is claimed22An optical evaluation method for evaluating the state of processing when performing processing on a substrate having a semiconductor region in a chamber, wherein the semiconductor region of the substrate in the chamber Irradiating measurement light, intermittently irradiating the semiconductor region with excitation light, and reflection of measurement light when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated Calculating a value obtained by dividing a difference in rate by a reflectance of measurement light when the excitation light is not irradiated as a change rate of reflectance.The processing is plasma etching processing of the semiconductor region..
[0061]
  By this method, when the semiconductor region is irradiated with excitation light, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region changes with and without excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the wavelength of the measurement light. Change. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, the reflectance change rate with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, so the change rate of the measurement light reflectance in the semiconductor region is calculated. The reflectance change rate reflects the crystal state of the semiconductor region. Therefore, it is possible to control the conditions of the processing performed in the chamber based on in-line light modulation reflectance measurement.
[0062]
  AlsoSince it becomes possible to control the depth of the damaged layer and the degree of damage caused by etching, it becomes possible to smoothly remove the damaged layer later.
[0063]
  According to a second aspect of the present invention, there is provided an optical evaluation method for evaluating a state of processing when a substrate having a semiconductor region is processed in a chamber. An optical evaluation method comprising: irradiating a semiconductor region of the substrate in the chamber with measurement light; intermittently irradiating the semiconductor region with excitation light; and irradiating the semiconductor region with excitation light. The value obtained by dividing the difference in the reflectance of the measurement light between when the excitation light is not irradiated and the reflectance of the measurement light when the excitation light is not irradiated is calculated as the reflectance change rate. With steps,The processing is light dry etching for removing a damaged layer caused by plasma etching of the semiconductor region.
[0064]
  By this method, when the semiconductor region is irradiated with excitation light, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region changes with and without excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the wavelength of the measurement light. Change. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, the reflectance change rate with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, so the change rate of the measurement light reflectance in the semiconductor region is calculated. The reflectance change rate reflects the crystal state of the semiconductor region. Therefore, it is possible to control the conditions of the processing performed in the chamber based on in-line light modulation reflectance measurement.
[0065]
  AlsoIt is possible to perform light dry etching for removing the damaged layer after grasping the depth of the damaged layer and the degree of damage caused by the etching.
[0066]
  According to a third aspect of the present invention, there is provided an optical evaluation method for evaluating a state of processing when a substrate having a semiconductor region is processed in a chamber. An optical evaluation method comprising: irradiating a semiconductor region of the substrate in the chamber with measurement light; intermittently irradiating the semiconductor region with excitation light; and irradiating the semiconductor region with excitation light. The value obtained by dividing the difference in the reflectance of the measurement light between when the excitation light is not irradiated and the reflectance of the measurement light when the excitation light is not irradiated is calculated as the reflectance change rate. With steps,The processing is formation of an insulating film on the semiconductor region.
[0067]
  By this method, when the semiconductor region is irradiated with excitation light, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region changes with and without excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the wavelength of the measurement light. Change. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, the reflectance change rate with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, so the change rate of the measurement light reflectance in the semiconductor region is calculated. The reflectance change rate reflects the crystal state of the semiconductor region. Therefore, it is possible to control the conditions of the processing performed in the chamber based on in-line light modulation reflectance measurement.
[0068]
  AlsoIt is possible to form an insulating film having desired characteristics, for example, a gate oxide film.
[0069]
  According to a fourth aspect of the present invention, there is provided an optical evaluation method for evaluating a state of processing when a substrate having a semiconductor region is processed in a chamber. An optical evaluation method comprising: irradiating a semiconductor region of the substrate in the chamber with measurement light; intermittently irradiating the semiconductor region with excitation light; and irradiating the semiconductor region with excitation light. The value obtained by dividing the difference in the reflectance of the measurement light between when the excitation light is not irradiated and the reflectance of the measurement light when the excitation light is not irradiated is calculated as the reflectance change rate. With steps,The processing is dry etching for removing the insulating film on the semiconductor region.
[0070]
  By this method, when the semiconductor region is irradiated with excitation light, carriers in the semiconductor region are excited and an electric field is generated by the carriers. Due to this electric field, the reflectivity of the measurement light guided to the semiconductor region changes with and without excitation light irradiation, and the rate of change depends on the magnitude of the electric field strength and the wavelength of the measurement light. Change. On the other hand, if there is a defect that becomes a recombination center of carriers in the semiconductor region, the lifetime of the excited carriers is shortened, so that the electric field strength formed by the carriers is reduced. In other words, the reflectance change rate with and without excitation light irradiation changes depending on the number of defects in the semiconductor region, so the change rate of the measurement light reflectance in the semiconductor region is calculated. The reflectance change rate reflects the crystal state of the semiconductor region. Therefore, it is possible to control the conditions of the processing performed in the chamber based on in-line light modulation reflectance measurement.
[0071]
  AlsoUsing the fact that the change rate of the reflectance of the measurement light from the semiconductor region is affected by the thickness of the insulating film, it is possible to control the progress of the removal of the insulating film by measuring the light modulation reflectance in-line. Become.
[0072]
  Claim26As claimed inAny one of 22 to 25In the step of irradiating the measurement light, the measurement light is applied to the surface of the substrate.DrippingIt is preferable to irradiate from a straight direction.
[0073]
  By this method, it is possible to perform light modulation reflectance measurement even for a semiconductor region having a small area.
[0074]
  Claim27As claimed in26In the step of irradiating the excitation light, the excitation light is applied to the surface of the substrate.DrippingIt is preferable to irradiate from a straight direction.
[0075]
  The method for managing a semiconductor device manufacturing apparatus according to the present invention is as follows.28A chamber for storing a substrate having a semiconductor region, a processing means for processing the substrate in the chamber, and a semiconductor of the substrate installed in the chamber First light supply means for irradiating the region intermittently with excitation light, second light supply means for irradiating the semiconductor region with measurement light, and reflection of measurement light irradiated on the semiconductor region A method for managing a semiconductor device manufacturing apparatus comprising a reflectance detection means for detecting a rate, wherein a first step of irradiating the semiconductor region with measurement light and intermittently irradiating the semiconductor region with excitation light Measurement light when the excitation light is not irradiated is the difference in the reflectance of the measurement light between the second step of the measurement and when the semiconductor region is irradiated with the excitation light and when the excitation light is not irradiated With reflectivity A third step of calculating the measured value as a change rate of the reflectance of the measurement light, and the processing means for a predetermined time until the change rate of the reflectivity calculated in the third step reaches a predetermined value. A fourth step for controlling to operate, and the predetermined time in the fourth step is monitored, and when the predetermined time exceeds a limit value, a signal for performing maintenance of the semiconductor device manufacturing apparatus is output. And a fifth step.
[0076]
  With this method, as the semiconductor device manufacturing apparatus is used, it is possible to monitor an increase in processing time until the reflectance change rate reaches a predetermined value due to deterioration of the constituent members in the chamber. Therefore, when the components in the chamber deteriorate, maintenance can be performed at an appropriate timing and without waste. By performing the maintenance, an appropriate processing time can be ensured, and the occurrence of defects in the semiconductor region due to the excessive processing time can be avoided.
[0077]
  Claim29As claimed in28The processing means can etch the semiconductor region by generating plasma in the chamber.
[0078]
  While performing plasma etching in the chamber by this method, for example, when the detection sensitivity of the change rate of the reflectance of the measurement light is deteriorated due to the deposit on the wall surface of the chamber generated during plasma processing, etc. Appropriate control can be maintained by performing maintenance of the chamber or the like.
[0079]
  Claim30As claimed in28In the above, the processing means may perform dry etching for generating a plasma in the chamber to remove a damaged layer caused by etching of the semiconductor region.
[0080]
  With this method, while performing dry etching to remove the damaged layer caused by etching, for example, the detection sensitivity of the change rate of the reflectance of the measurement light is deteriorated due to the deposit on the wall surface of the chamber generated during plasma processing. In the event of a failure, maintenance of the chamber or the like can be performed to maintain proper control.
[0081]
  Claim31As claimed in28In the above, the processing means may introduce impurities into the semiconductor region.
[0082]
  While performing the impurity introduction process by this method, for example, when the detection sensitivity of the change rate of the reflectance of the measurement light is deteriorated due to the deposit on the wall surface of the chamber generated at the time of impurity introduction, the chamber or the like Therefore, proper control can be maintained.
[0083]
  Claim32As claimed in28The processing means may perform annealing after ion implantation is performed on the semiconductor region.
[0084]
  With this method, while performing annealing to recover the structural disturbance caused by ion implantation, if the chamber members deteriorate due to annealing performed at a high temperature, maintenance of the chamber or the like is performed. Proper control can be maintained.
[0085]
  Claim33As claimed in28In the above, the processing means may form a thin insulating film on the semiconductor region.
[0086]
  While this method is used to form an insulating film by thermal oxidation, CVD, etc., for example, when the detection sensitivity of the change rate of the reflectance of the measurement light is deteriorated due to deterioration of the member in the chamber that occurs during thermal oxidation The maintenance of the chamber or the like can be performed to maintain proper control.
[0087]
  Claim34As claimed in28When a thin insulating film is formed on the semiconductor region, the processing means can perform dry etching for removing the thin insulating film on the semiconductor region.
[0088]
  With this method, while performing dry etching to remove the damaged layer caused by etching, for example, the detection sensitivity of the change rate of the reflectance of the measurement light is deteriorated due to the deposit on the wall surface of the chamber generated during plasma processing. In the event of a failure, maintenance of the chamber or the like can be performed to maintain proper control.
[0089]
  Claim35As claimed in28 to 34In any one of the above, it is preferable that the reflectance detection unit detects the reflectance of measurement light in a wavelength range of 600 nm or less.
[0090]
  Claim36As claimed in35In the above, it is more preferable that the reflectance detection means detects the reflectance of measurement light in the wavelength range of 300 to 600 nm.
[0091]
  Claim37As claimed in28 to 36In any one of the above, in the step of calculating the reflectance change ratio, the spectrum of the reflectance change ratio of the measurement lightThe poles ofThe change ratio of the reflectance of the measurement light at the specific energy value of the measurement light that gives the value can be calculated.
[0092]
  Claim38As claimed in28 to 37In any one of the above, it is preferable that the reflectance detection means is configured to detect the reflectance of reflected light of a specific wavelength using an optical filter.
[0093]
  Claim39As claimed in28 to 38In any one of the above, the semiconductor region is preferably made of n-type silicon.
[0094]
  Claim40As claimed in28 to 39In any one of the above, in the step of irradiating the excitation light, it is preferable to irradiate the excitation light intermittently at a frequency of 1 kHz or less.
[0095]
DETAILED DESCRIPTION OF THE INVENTION
    (First embodiment)
  Hereinafter, a first embodiment of the present invention will be described.
[0096]
  FIG. 4 is a cross-sectional view schematically showing a configuration of an etching apparatus provided with means for observing the reflection intensity R according to the first embodiment. As shown in the figure, an anode electrode 213 that is a lower electrode and a cathode electrode 214 that is an upper electrode are disposed in the reaction processing chamber 200, and a workpiece is placed on the anode electrode 213. A wafer 103 made of p-type silicon is provided. When high frequency power is supplied between the electrodes 213 and 214 from the high frequency power supply 211 via the coupling capacitor 212, plasma 401 is generated in the reaction processing chamber 200. Further, an end point detection window 215, a probe light incident window 218, and a reflected light observation window 219 are provided on the wall surface of the reaction processing chamber 200.
[0097]
  On the other hand, an end point detection system 216 is provided outside the reaction processing chamber 200, and a member for observing the reflection intensity R is provided. First, an Xe lamp 302 that generates probe light for irradiating the n-type semiconductor region 101 is provided. After the probe light 403 generated by the Xe lamp 302 is reflected by the mirror 217, the probe light incident window 218 is opened. To the n-type semiconductor region 101 of the wafer 103 installed in the reaction processing chamber 200. Then, the reflected probe light 404 reflected by the n-type semiconductor region 101 is taken out of the reaction processing chamber 200 from the reflected light observation window 219, and its intensity (particularly, wavelength 376 nm, energy 3) is reflected by the reflected intensity observation system 220. .About 3 eV) is detected. Data relating to the reflection intensity measured by the reflection intensity observation system 220 is sent to the etching control system 222 via the signal path 221. Further, an Ar ion laser 301 that generates excitation light for irradiating the n-type semiconductor region 101 is provided. The excitation light 402 generated by the Ar ion laser 301 is chopped by a chopper 223 at a frequency of 200 Hz, and intermittently. Sent to. The excitation light 402 is sent into the reaction processing chamber 200 through the end point detection window 215 and is intermittently applied to the n-type semiconductor region 101. As described above, when the excitation light 402 is not irradiated, the difference ΔR in the reflection intensity (that is, the intensity of the reflected probe light 404) of the probe light 403 when the excitation light 402 is irradiated and when it is not irradiated is calculated. The value (ΔR / R) divided by the reflection intensity R is detected by the reflection intensity observation system 220 as a change rate of the reflection intensity. With the above configuration, the change in the change rate of the reflection intensity is monitored. In general, in the optical system according to this embodiment and each of the embodiments described later, a polarizer is often disposed on the probe light incident side and an analyzer is disposed on the reflection side.
[0098]
  Here, it is considered that such a change rate (ΔR / R) of the reflection intensity is caused by the following action. In general, when a semiconductor is irradiated with light, the number of carriers is increased by being excited by the light, and thereafter, when the carriers return to the original energy level, the light is emitted and disappears. The electric field strength changes with the change in the number of carriers. Therefore, the reflection intensity differs between when the excitation light is irradiated and when the excitation light is not irradiated. However, when there are many defects in the semiconductor, an interface level having a low energy level exists due to the defects. In addition, since defects having such interface states function as a carrier trap layer, even if light is irradiated, carriers are trapped by the defects and are not excited to a sufficiently high energy level, or a high energy level. When carriers excited to a level are trapped by a defect, the intensity of light generated when the carriers are excited to return to a low energy level is lowered, and the electric field strength is also changed. Therefore, the change rate (ΔR / R) of the reflection intensity decreases as the depth of the damaged layer and the degree of damage increase. Therefore, information on the damaged layer can be obtained by monitoring the change rate of the reflection intensity.
[0099]
  The chopping frequency seems to be related to the time when the electric field strength changes due to recombination of carriers, and it has been found from experiments that 1 kHz or less is preferable, and 500 Hz or less is more preferable. Moreover, it is preferable that the energy of the photon of the excitation light is larger than the band gap of the semiconductor region. When using a silicon substrate, it is preferable to use excitation light having a wavelength of photon energy of 1.1 eV or more. The above also applies to each embodiment described later.
[0100]
  In this embodiment, since the irradiation intensity (in each wavelength region) of the measurement light is assumed to be constant, the detection is replaced with the detection of the reflectance by detecting the reflection intensity. That is, the change rate of the reflection intensity is measured by continuously irradiating the n-type semiconductor region 101 with the excitation light 402, which is Ar ion laser light, while continuously irradiating the probe light 403, which is Xe lamp light, from another direction. Irradiation is performed by detecting a change in the reflection intensity of the probe light 403. That is, the difference ΔR between the reflection intensity when the excitation light 402 is irradiated on the n-type semiconductor region 101 and the reflection intensity when the excitation light 402 is not irradiated is irradiated with the excitation light 402 on the n-type semiconductor region 101. The value (ΔR / R) divided by the reflection intensity R when not being used is the difference in reflection intensity, that is, the reflectance.
[0101]
  Here, changing the wavelength of the probe light while repeating irradiation and non-irradiation of excitation light, measuring the reflectance change rate for each wavelength (light energy value), and examining its spectral shape is a light This is called modulated reflectance spectroscopy. For example, FIG. 22 is a spectrum diagram showing the relationship between the value of energy proportional to the reciprocal of the wavelength λ of the probe light incident on the single crystal silicon layer, which is a semiconductor region, and the reflectance change rate (ΔR / R). . However, the reflectance change rate (ΔR / R) in the figure is a relative value where the initial state is zero. In the present embodiment, the wavelength 376 nm of the probe light corresponding to the highest energy value 3.30 eV (energy value indicating almost extreme value) at which the reflectance change rate (ΔR / R) varies is used. Yes.
[0102]
  FIG. 3 is a top view schematically showing the structure of the wafer according to the present embodiment. As shown in FIG. 3, on a wafer 103 made of p-type silicon, a chip region Rtp that is finally cut out from the wafer to become a semiconductor chip and a monitor region Rmn for optical evaluation are provided. .
[0103]
  Next, the relationship between the progress of the etching process and the measurement of the change rate of reflection intensity (ΔR / R) in this embodiment will be described with reference to the cross-sectional structure of the wafer. 2A to 2C are cross-sectional views of the wafer showing the manufacturing process of the semiconductor device according to the present embodiment.
[0104]
  Before the process shown in FIG. 2A, the area of the monitor region Rmn on the wafer 103 is, for example, 13 × 13 μm.²The n-type semiconductor region 101 (specific resistance is about 0.02 Ωcm) 101 is formed. On the other hand, various semiconductor elements are formed in the chip region Rtp. In FIG. 2A, for example, a gate electrode 106 made of polysilicon, a gate oxide film 107 having a thickness of 6 nm, for example, and n A MOS transistor having a type source region 108 and an n type drain region 109 is shown. An interlayer insulating film 104 is deposited on the entire surface of the wafer. In the present embodiment, the n-type semiconductor region 101 is doped with the same conductivity type and the same concentration as the n-type source region 108 and the n-type drain region 109. However, as described later, the monitor region Rmn The inner semiconductor region may be doped with impurities having a different conductivity type and different concentration from the source / drain regions in the semiconductor element to be monitored. In particular, by increasing the impurity concentration in the monitor region Rmn, the detection sensitivity of the etching damage removal state can be further increased.
[0105]
  2B, a contact hole forming photoresist mask 105 is formed on the interlayer insulating film 104, and the interlayer insulating film 104 is selectively removed using the photoresist mask 105. Dry etching is performed. This dry etching is processing using plasma as will be described later, and the etching conditions are as follows, for example. A mixed gas of Ar gas, CHF3 gas, and CF4 gas is used. The gas flow rate is 80 sccm for Ar gas, 45 sccm for CHF3 gas, 20 sccm for CF4 gas, and the overall gas pressure is 80 mTorr. By this dry etching process, openings 110a and 110b, which are contact holes reaching the n-type source region 108 and the n-type drain region 109 of the MOS transistor, are formed, and at the same time, the monitoring holes reaching the n-type semiconductor region 101 are formed. An opening 110c is formed. At the time when the formation of each of the openings 110a to 110c by the plasma emission method is detected, the n-type source region 108, the n-type drain region 109, and the n-type semiconductor region 101 on the wafer are damaged layers Rdm1 and Rdm2. , Rdm3 are formed.
[0106]
  Next, in the step shown in FIG. 2C, light etching (dry etching) for removing the damaged layers Rdm1 to Rdm3 generated by dry etching is performed. At this time, in this embodiment, the gas flow rate and pressure are not changed, and the condition where the power is reduced to 200 W is applied.
[0107]
  FIG. 1 is a flowchart showing a general procedure of an optical monitor during plasma processing.
[0108]
  First, main etching is performed in step ST100, and when the main etching is completed, an initial reflection intensity change rate (ΔR / R) of the n-type semiconductor region 101 is measured in step ST101. In this embodiment, the measured value for the n-type semiconductor region 101 after the main etching is finished is defined as an initial reflection intensity change rate (ΔR / R).
[0109]
  Next, plasma processing is performed in step ST102, and in step ST103, the reflection intensity change rate (ΔR / R) during the plasma processing is monitored. In this embodiment, light etching is performed as plasma processing, and the change rate (ΔR / R) of the reflection intensity during light etching is monitored.
[0110]
  Further, in step ST104, the change rate (ΔR / R) of the reflection intensity during the plasma treatment (light etching in the present embodiment) is compared with the change ratio (ΔR / R) of the initial reflection intensity, and obtained in advance by experiments. Until it is determined that the reference value for determining that the plasma processing has been completed is reached, the processing in steps ST102 to ST104 is performed. When it is determined that the plasma processing is completed, the plasma processing is terminated in step ST105. In this embodiment, when it is determined that the removal of the damaged layer is completed, the light etching is finished in step ST105.
[0111]
  Here, the relationship between the change rate of the reflection intensity and the state of the damaged layer in the present embodiment will be described. FIG. 5 is a diagram showing the temporal change in the ratio of the change rate (ΔR / R) of the reflection intensity at the wavelength of 376 nm (energy 3.3 eV) to the initial value. As shown in FIG. 5, immediately after the start of the light etching (between 0 and 20 seconds), the change rate (ΔR / R) of the reflection intensity is larger than the time when the dry etching of the main step is finished, and the initial value is reached. It can be seen that the damaged layer has been removed. However, as the light etching time increases (after 20 seconds), the ratio of the change rate of reflection intensity (ΔR / R) to the initial value is higher than the value at the start of light etching (about 0.6 in the example shown in FIG. 5). It can be seen that damage to the Si crystal (substrate) increases due to excessive light etching.
[0112]
  On the other hand, as shown in FIG. 6, the correlation between the light etching time and the resistance value (contact resistance) of the contact portion can be obtained by conducting an experiment in advance. As shown in FIG. 6, in the initial stage of light etching, the contact resistance is large, but this is because the organic polymer generated by the main etching is deposited near the bottom of the contact hole. It can be seen that it is being removed gradually. As can be seen from a comparison between FIG. 6 and FIG. 5, there is a correlation between the contact resistance and the rate of change in reflection intensity (ΔR / R). From this correlation, in order to obtain a standard value of contact resistance (50 ± 5Ω when the cross-sectional dimension of the contact window is 0.6 μm), the reflection intensity change rate (ΔR / R) is 60 from the initial value. It can be seen that the value must be greater than or equal to%. Therefore, by completing the light etching step when the reflection intensity change rate (ΔR / R) reaches 60%, the damage layer generated by the main etching is almost removed, and then new damage caused by the light etching is removed. Generation | occurence | production can be suppressed and the semiconductor device which has favorable joining can be implement | achieved.
[0113]
  FIG. 7 shows the contact resistance of the MOS transistor formed by the light etching of this embodiment performed with optical monitoring for obtaining information on the damaged layer, and the conventional light etching without such optical monitoring. The data for comparing the contact resistance of the MOS transistor formed by. As shown in the figure, by using the manufacturing method of the semiconductor manufacturing apparatus of this embodiment, it is possible to suppress contact resistance variation compared to the conventional method, and to manufacture a semiconductor device with high quality and reliability. it can.
[0114]
  Next, advantages obtained by monitoring the damaged layer by light modulation reflectance spectroscopy as in this embodiment will be described. Generally, the penetration depth of ions when plasma treatment is performed is about several tens of nm. Here, since the penetration depth of microwaves such as infrared rays into the semiconductor substrate is 1 μm or more, the information obtained from the reflectance includes not only information from the damaged layer but also information from areas other than the damaged layer. It is difficult to accurately extract information on only the damaged layer. Therefore, these methods are not suitable as detection methods for minute regions such as etching damage. On the other hand, when performing optical monitoring using light in a region below visible light, the depth of penetration into the semiconductor substrate is about several hundreds nm, so that the detection sensitivity for a damaged layer having a depth of several tens of nm is extremely high. Get higher. Moreover, by directly irradiating the surface of the etched semiconductor wafer with light, information on the damaged layer can be obtained directly. By performing such optical monitoring using light in a region below visible light, It can provide very useful information for in-line evaluation and process control. From this point of view, in the light modulation reflectance measurement method in the present embodiment and each of the embodiments described later, the measurement light in the wavelength range of 600 nm or less can be detected by selecting the light source of the measurement light or attaching a filter. Preferably, it is more preferable to detect measurement light in the wavelength range of 300 to 600 nm.
[0115]
  In the present embodiment, the monitor region Rmn is provided in the wafer 103 in addition to the chip region Rtp. However, the present invention is not limited to such an embodiment, and the optical region in the chip region Rtp is not limited thereto. Even if an evaluation pattern is provided, the same effect as in the present embodiment can be obtained.
[0116]
  Furthermore, by managing the fluctuation amount of the change rate (ΔR / R) of the reflection intensity due to the light etching process within a certain time, it is possible to quickly grasp the abnormality of the apparatus and prevent the apparatus trouble.
[0117]
  In the above embodiment, the etching process is dry etching using plasma. However, the present invention is not limited to such an embodiment. For example, dry etching that does not use plasma by sputtering, wet etching, or the like. Even can be applied.
[0118]
  Further, the present invention can be applied not only to etching for removing a damaged layer in a semiconductor region having a large damaged layer at the beginning, but also to etching for etching a semiconductor region having almost no damaged layer.
[0119]
  Further, in the above embodiment, the impurity concentration of the source / drain regions 108 and 109 which are the first semiconductor regions in the chip region Rtp and the n-type semiconductor region 101 in the monitoring region Rmn which is the second semiconductor region Although the depth is the same, the present invention is not limited to such an embodiment, and the first semiconductor region and the second semiconductor region may have different impurity concentrations and impurity conductivity types. To do. This is because, if an experiment is performed in advance, the optical characteristics (contact resistance in the above embodiment) in the second semiconductor region for obtaining appropriate contact resistance in the first semiconductor region can be known. For example, it is also possible to increase the detection sensitivity of the change rate of the reflection intensity by increasing the impurity concentration in the monitor region Rmn.
[0120]
  In this embodiment, as shown in FIG. 4, the angle of the probe light 403 with respect to the substrate surface is smaller than the angle of the excitation light 402, but the angle of the probe light 403 that requires measurement of the reflection intensity is increased. It is preferable to reduce the area of the second semiconductor region to be monitored.
[0121]
    (Second Embodiment)
  FIG. 8 shows an optical monitoring system in this embodiment. As shown in the figure, an Xe lamp 502 that generates probe light, which is measurement light irradiated to the n-type semiconductor region 101, is provided, and the probe light 507 generated by the Xe lamp 502 is reflected by a mirror 506. Thereafter, the wafer is sent to the n-type semiconductor region 101 on the wafer 103 placed on the wafer stage 504. Then, the reflected probe light 508 reflected by the n-type semiconductor region 101 passes through the mirror 506 and is sent to the microscope system 505, and the intensity (particularly, near the wavelength of 376 nm) is detected by the observation system / analysis system 509. The In the present embodiment, irradiation of the probe light 507 to the observation region and extraction of the reflected probe light 508 can be performed from a direction perpendicular to the surface of the sample by using the microscope system 505 and the mirror 506 together. This is a major point different from the first embodiment. Further, the diameter of the probe light 507 can be reduced to 10 μmφ by the lens 510. Data relating to the reflection intensity measured by the observation system / analysis system 509 is sent to an etching control system (not shown) via a signal line.
[0122]
  In addition, an Ar ion laser 503 having an intensity of 5 W that generates excitation light for irradiating the n-type semiconductor region 101 is provided. The excitation light 511 generated by the Ar ion laser 503 is chopped by the chopper 510 at a frequency of 100 Hz. The n-type semiconductor region 101 is irradiated intermittently. As described above, when the excitation light 511 is not irradiated, the difference ΔR between the reflection intensity of the probe light 507 (that is, the intensity of the reflected probe light 508) when the excitation light 511 is irradiated and when it is not irradiated is determined. A value (ΔR / R) divided by the reflection intensity R is detected by the observation system / analysis system 509 as a change rate of the reflection intensity. With the above configuration, the change in the change rate of the reflection intensity of the probe light is monitored. Note that a reflected excitation light observation system 513 for detecting the intensity of the reflected excitation light 512 from the semiconductor region 101 is also provided, and information regarding the intensity of the reflected excitation light 512 is provided through an observation system / analysis system 509 via a signal line. Sent to. Note that the chopper 510 and the detector that detects the intensity of the reflected light are configured to operate in synchronization.
[0123]
  Also in this embodiment, as in the first embodiment, as shown in FIG. 3, a chip region that is finally cut out from the wafer and becomes a semiconductor chip on the wafer 103 made of p-type silicon. Rtp and a monitor region Rmn for optical evaluation are provided.
[0124]
  Next, the plasma etching method in the present embodiment will be described with reference to FIGS.
[0125]
  Before the process shown in FIG. 9A, the area of the monitor region Rmn on the wafer 103 is, for example, 13 × 13 μm.²The n-type semiconductor region 101 (specific resistance is about 0.02 Ωcm) 101 is formed. On the other hand, various semiconductor elements are formed in the chip region Rtp. In FIG. 9A, for example, a gate electrode 106 made of polysilicon, a gate oxide film 107 having a thickness of 6 nm, for example, and n A MOS transistor having a type source region 108 and an n type drain region 109 is shown. An interlayer insulating film 104 is deposited on almost the entire surface of the wafer. In the present embodiment, the n-type semiconductor region 101 is doped with the same conductivity type and the same concentration as the n-type source region 108 and the n-type drain region 109. However, as described later, the monitor region Rmn The inner semiconductor region may be doped with impurities having a different conductivity type and different concentration from the source / drain regions in the semiconductor element to be monitored.
[0126]
  Next, in a step shown in FIG. 9B, a contact hole forming photoresist mask 105 is formed on the interlayer insulating film 104, and the interlayer insulating film 104 is selectively removed using the photoresist mask 105. Dry etching is performed. This dry etching is etching using plasma, and the etching conditions are, for example, a mixed gas of Ar gas, CHF3 gas and CF4 gas, Ar gas flow rate of 80 sccm, and CHF3 gas in a chamber (not shown). A high-frequency discharge is performed at a power of 400 W with a flow rate of 45 sccm, a flow rate of CF4 gas of 20 sccm, and an overall gas pressure of 80 mTorr. By this dry etching process, openings 110a and 110b, which are contact holes reaching the n-type source region 108 and the n-type drain region 109 of the MOS transistor, are formed, and at the same time, the monitoring holes reaching the n-type semiconductor region 101 are formed. An opening 110c is formed. At the time when the formation of the openings 110 a to 110 c by the plasma emission method is detected, the n-type source region 108, the n-type drain region 109, and the n-type semiconductor region 101 on the wafer 103 are damaged layers Rdm 1. Rdm2 and Rdm3 are respectively formed.
[0127]
  Next, in the step shown in FIG. 9C, light etching (dry etching) for removing the damaged layers Rdm1 to Rdm3 generated by dry etching is performed. At this time, in this embodiment, the gas flow rate and pressure are not changed, and the condition where the power is reduced to 200 W is applied.
[0128]
  FIG. 10 shows data obtained by measuring the change rate of the reflection intensity of the probe light when the intensity of the irradiation excitation light is changed for the sample that has been subjected to the plasma treatment and the sample that has not been subjected to the plasma treatment. As can be seen from the data shown in the figure, the value of the change in probe light reflection intensity (ΔR / R) of the sample subjected to plasma processing is smaller than that of the sample not subjected to plasma processing.
[0129]
  Therefore, also in the present embodiment, similarly to the first embodiment, light etching is performed by a desired amount by using light modulation reflectance spectroscopy, thereby forming source / drain regions made of low-resistance semiconductor regions. And so on.
[0130]
  In particular, as in this embodiment, when the probe light 507 is incident on the surface of the wafer from the vertical direction and the reflection intensity is detected, the probe light is incident from the direction inclined with respect to the surface of the substrate. Compared to the above, since it is possible to easily evaluate the Si damage layer in the minute region, there is an advantage that the useless space of the monitor region Rmn can be reduced.
[0131]
  When the probe light 507 is incident from the vertical direction, the reflection intensity increases, that is, the detection sensitivity increases. In other words, in order to actually perform highly accurate measurement, it is necessary to integrate data obtained by performing chopping many times at one measurement point in order to increase the S / N ratio. However, when the probe light 507 is incident from the vertical direction, a high S / N ratio can be obtained by measurement per chopping, so that the number of choppings is reduced and the evaluation time is shortened. Specifically, for example, when the light is incident on the wafer surface from the vertical direction, the evaluation time is 15 to 3 minutes per sheet as compared with the case where the light is incident from a direction inclined by 45 °. Can be greatly reduced. When evaluating the damaged layer of etching in-line, it can be said that the merit by shortening the evaluation time is extremely large.
[0132]
  In the present embodiment, the monitor region Rmn is provided in the wafer 103 in addition to the chip region Rtp. However, the present invention is not limited to such an embodiment, and the optical region in the chip region Rtp is not limited thereto. Even if an evaluation pattern is provided, the same effect as in the present embodiment can be obtained. Further, when the probe light is irradiated from the direction perpendicular to the surface of the substrate, the contact window can be directly observed without providing an optical evaluation pattern separately.
[0133]
  Also, by managing the amount of change in the change rate (ΔR / R) of the reflection intensity due to the light etching process within a certain time, it is possible to quickly grasp the abnormality of the apparatus and prevent the apparatus trouble.
[0134]
  In the first and second embodiments, the etching process is dry etching using plasma. However, the present invention is not limited to such an embodiment, and for example, dry etching that does not use plasma by sputtering or the like. It can also be applied to wet etching and the like.
[0135]
  In the first and second embodiments, not only etching for removing a damaged layer is initially performed on a semiconductor region having a large damaged layer, but also a semiconductor region having almost no damaged layer is etched. It can also be applied to the etching of Furthermore, in order to obtain a wide range of information on the structure of the semiconductor region, such as detection of the film thickness during the formation or removal of the silicon oxide film, detection of the degree of crystallinity recovery during the annealing of the semiconductor substrate, the optical of the present invention An evaluation method can also be used.
[0136]
  Further, in the first and second embodiments, the source / drain regions 108 and 109 which are the first semiconductor regions in the chip region Rtp and the n-type semiconductor region 101 in the monitoring region Rmn which is the second semiconductor region. However, the present invention is not limited to such an embodiment, and the first semiconductor region and the second semiconductor region have different impurity concentrations and impurity conductivity types. It may be. This is because, if an experiment is performed in advance, the optical characteristics (contact resistance in the above embodiment) in the second semiconductor region for obtaining appropriate contact resistance in the first semiconductor region can be known. For example, it is also possible to increase the detection sensitivity of the change rate of the reflection intensity by increasing the impurity concentration in the monitor region Rmn.
[0137]
    (Third embodiment)
  In this embodiment, an embodiment of an optical monitoring system will be described. The semiconductor device processing method can be performed in the same manner as the first and second embodiments and the deformable form noted above.
[0138]
  FIG. 11 is a perspective view showing an optical evaluation apparatus in the present embodiment. In the figure, the same components as those shown in FIG. That is, as in the second embodiment, a wafer stage 504, an Xe lamp 502, a mirror 506, an Ar ion laser 503, a chopper 510, and an observation system / analysis system 509 are provided. The feature of this embodiment is that the mirror 523 for guiding the excitation light 511 and the probe light 507 coaxially, and the reflected light in which excitation light and probe light reflected from the n-type semiconductor region of the wafer 103 are mixed. This is the point that a spectroscope 521 for splitting 518 and a detector 522 for detecting the intensity of light at each wavelength split by the spectroscope 521 are provided. The Xe lamp 502, the mirrors 506 and 523, the Ar ion laser 503, the chopper 510, and the spectroscope 521 constitute an optical system 530.
[0139]
  In the optical evaluation apparatus according to the present embodiment, the probe light 507 generated by the Xe lamp 502 and the excitation light 511 generated by the Ar ion laser 503 are guided coaxially by the mirror 523 and together by the mirror 506. After being reflected, the light is sent to the n-type semiconductor region 101 on the wafer 103 placed on the wafer stage 504. Then, the reflected light 518 mixed with the reflected probe light and the reflected excitation light reflected by the n-type semiconductor region is sent to the spectroscope 521 through the mirror 506, and its intensity is detected by the detector 522. The intensity change is analyzed by the observation system / analysis system 509.
[0140]
  Therefore, the sample subjected to the plasma treatment can be evaluated by the same method as the method shown in the second embodiment using the optical evaluation apparatus of the present embodiment. In addition, in the present embodiment, the probe light and the excitation light are guided to the common optical axis and then incident on the n-type semiconductor region on the wafer 103 that is the observation point. Can be very easily aligned, and the configuration of the apparatus is simplified.
[0141]
  Furthermore, with the configuration of this embodiment, it is possible to easily evaluate the Si damage layer in a finer semiconductor region as compared with the method shown in the second embodiment. In addition, since the excitation light also enters from the vertical direction, the beam diameter can be reduced to about 30 μm, and the sample evaluation at a smaller observation point should be performed compared to the case where the excitation light is incident from a direction inclined by 45 °. Can do. Also, the evaluation time can be shortened to about 20% of that of the second embodiment.
[0142]
  Therefore, even if a separate monitor region is not provided in the wafer, if there is a wider semiconductor region in the LSI of the wafer, it is possible to measure the damage or the like of the plasma processing using that.
[0143]
    (Fourth embodiment)
  FIG. 12 is a perspective view showing an optical evaluation apparatus according to the fourth embodiment. In the figure, the same components as those shown in FIG. That is, as in the third embodiment, a wafer stage 504, an Xe lamp 502, mirrors 506 and 523, an Ar ion laser 503, a chopper 510, and an observation system / analysis system 509 are provided. . A feature of this embodiment is that a filter 525 (peak wavelength) for passing light in a specific wavelength range among reflected light 518 in which probe light and excitation light reflected from the n-type semiconductor region of the wafer 103 are mixed. And 350 nm) and a detector 524 for detecting the intensity of the light that has passed through the filter 525. The Xe lamp 502, the mirrors 506 and 523, the Ar ion laser 503, the chopper 510, and the filter 525 constitute an optical system 530.
[0144]
  In the optical evaluation apparatus of the present embodiment, unlike the methods of the above-described embodiments, the change rate of the reflection intensity in the specific wavelength range of the probe light can be observed without spectroscopy. By this method, the time required for evaluation can be reduced to the order of several seconds.
[0145]
  FIG. 13 shows the change rate (ΔR / R) of the reflection intensity of the probe light after 20 seconds of light etching using the optical evaluation apparatus of the present embodiment, with the RF bias power changed. It is a figure which shows a result. In this case, since the reflected probe light is not spectrally analyzed and the spectrum is analyzed, the light transmitted through the filter 525 is observed by the detector 524. Therefore, the result shown in the figure shows that the wavelength characteristics range from 350 nm to 390 nm. It is considered that the light intensity is integrated and detected. As can be seen from FIG. 13, since the rate of change (ΔR / R) in the reflection intensity of the probe light decreases as the plasma intensity increases, the damage in the processing region increases. That is, also in the method of the present embodiment, it was possible to clearly detect the difference in the change rate of the reflectance of the measurement light due to the difference in the degree of plasma processing. In this embodiment, as described above, since the spectrum analysis is not necessary, the evaluation time can be shortened to the order of several seconds.
[0146]
    (Fifth embodiment)
  FIG. 14 is a perspective view showing an optical evaluation device in the fifth embodiment. In the figure, the same components as those in FIG. 11 are denoted by the same reference numerals. That is, as in the third embodiment, a wafer stage 504, an Xe lamp 502, a chopper 510, a spectroscope 521, and a detector 522 are provided. The feature of this embodiment is that a beam splitter 526 that separates the light generated by the Xe lamp 502 into the probe 507 and the excitation light 511 in the optical system 530, and a mirror 527 for reflecting the excitation light 511, , A mirror 528 that reflects the probe light 507 and transmits the reflected light 518 from the wafer 103, and a combination that transmits the probe light 507 and reflects the excitation light 511 to guide both of them to the wafer and transmit the reflected light. The mirror 529 is provided. The Xe lamp 502, the chopper 521, the beam splitter 526, the mirrors 527 and 528, the combination mirror 529, and the spectroscope 521 constitute an optical system 530.
[0147]
  That is, in this embodiment, unlike the above embodiments, the light from the Xe lamp 502, which is one light source, is separated into the probe light 507 and the excitation light 511, and then the same light as in each of the above embodiments. Modulated reflectance spectroscopy measurement is performed. Therefore, according to this embodiment, since only one light source is required, the optical system 530 can be made compact as shown in FIG. 14, and since it is not necessary to use a laser, low cost and improvement in maintenance efficiency are achieved. Can be achieved.
[0148]
  FIG. 15 shows the change ratio (ΔR / R) of the reflection intensity of the probe light after the light etching is performed for 20 seconds using the optical evaluation apparatus of the present embodiment, with the RF bias power changed. It is a figure which shows a result. As can be seen from FIG. 15, since the rate of change (ΔR / R) in the reflection intensity of the probe light decreases as the plasma intensity increases, the damage in the processed region increases. That is, also in the method of the present embodiment, it is possible to clearly detect the difference in the change in the reflectance of the measurement light due to the difference in the processing level of the plasma treatment.
[0149]
  FIG. 16 shows the measurement of the change over time in the ratio of the change rate (ΔR / R) of the reflection intensity of the probe light at the wavelength of 376 nm (energy 3.3 eV) to the initial value using the optical evaluation apparatus of the present embodiment. It is a figure which shows a result. As shown in the figure, the change in the change rate (ΔR / R) of the reflection intensity of the probe light with the progress of light etching is basically the same as the change shown in FIG. However, in the present embodiment, the value of the reflection intensity change rate (ΔR / R) itself is larger than the value shown in FIG. This means that the sensitivity is increased by inputting the excitation light from above.
[0150]
    (Plasma processing apparatus common to the second to fifth embodiments)
  FIG. 17 is a cross-sectional view schematically showing the structure of a plasma processing apparatus commonly used in the second to fifth embodiments. As shown in the figure, the plasma processing apparatus includes a chamber 200, an RF power source 211 for supplying high-frequency power for generating plasma, a coupling capacitor 212, and a lower electrode 213 installed at the bottom of the chamber 200. And an upper electrode 214 installed on the ceiling of the chamber 200, viewing windows 218 and 219 provided on the side wall of the chamber 200, and an observation window 220 provided near the center of the ceiling of the chamber 200. ing. However, the wafer stage is not shown in the figure. Then, a plasma region 401 is generated between the upper electrode 214 and the lower electrode 213 by the high frequency power supplied from the RF power source 211, and the n-type semiconductor region 101 in the wafer 103 placed on the lower electrode 213 is processed. Is configured to do.
[0151]
  And in the said 3rd-5th embodiment, as shown in FIG. 17, the optical system 530 can be collectively arrange | positioned above the observation window 220 of the chamber 200. FIG. However, in the second embodiment, only the optical system for probe light is arranged above the observation window 220, and the optical system for excitation light is arranged beside the viewing windows 218 and 219.
[0152]
  Such a structure of the plasma processing apparatus makes it possible to enter at least probe light from a direction perpendicular to the wafer surface, and to realize process observation in real time by observing changes in the reflectance of the probe light. Can do it. In addition, the signal 531 from the optical system can be used to provide feedback to the processing conditions.
[0153]
    (Sixth embodiment)
  FIG. 18 is a cross-sectional view schematically showing a configuration of a heat treatment apparatus (annealing apparatus) for a semiconductor device according to the sixth embodiment. As shown in FIG. 18, a quartz tube 603 is attached in a reaction vessel 607, and a wafer 103 is placed on the inner surface of the quartz tube 603 via a wafer susceptor 602. A heater 604 using infrared rays is mounted on the outer surface of the quartz tube 603, and the wafer 103 in the quartz tube 603 is heated by the heater 604. The reaction vessel 607 is provided with a reaction gas introduction port 609 and a reaction gas discharge port 610 so that the flow rate of the reaction gas can be appropriately adjusted by a flow rate controller 608. In addition, two observation quartz windows 605 and 606 are provided on the side of the reaction vessel 607 so as to face each other. A part of the wafer 103 is provided with an n-type semiconductor region 101 (specific resistance value of about 0.02 Ωcm), and light incident on the n-type semiconductor region 101 on the wafer 103 from one observation quartz window 605 is provided. The other observation quartz window 606 can be taken out. Although not shown in the n-type semiconductor region 101 of the wafer 103, a pattern for optical evaluation (size is 13 × 13 μm)² ) Is provided.
[0154]
  Further, outside the reaction vessel 607, an Xe lamp 611 that generates probe light 618 that is measurement light incident on the reaction vessel 607, and an Ar ion laser 612 that generates excitation light 620 in the reaction vessel 607 (output 1 W) ), A chopper 614 that chops the excitation light 620 at a frequency of 200 Hz, and a detector 613 that receives the reflected probe light 619 reflected from the n-type semiconductor region 101 on the wafer 103 and detects its intensity. ing. That is, the probe light 618 generated by the Xe lamp 611 is irradiated to the n-type semiconductor region 101 on the wafer 103 as an evaluation pattern, while the excitation light 620 generated by the Ar ion laser 612 is also chopped by the chopper 614 at a frequency of 200 Hz. The n-type semiconductor region 101 on the wafer 103 is irradiated, and a change in reflectance is monitored from a change in intensity of the reflected probe light 619 from the n-type semiconductor region 101 due to irradiation / non-irradiation of excitation light 620. ing. The control system computer 615 controls the operation of the heater 604, the chopper 614, and the flow rate controller 608, and takes in the detection signal of the detector 613 to monitor the optical characteristics of the n-type semiconductor region 101. ing. The chopper 614 and the detector 613 that detects the intensity of the reflected light are configured to operate in synchronization.
[0155]
  Next, the principle of the optical evaluation method using the change in reflectance will be described.
[0156]
  The change rate of the reflectance of the measurement light is a difference ΔR between the reflectance of the measurement light when the excitation light is irradiated on the semiconductor region to be evaluated and the reflectance when the excitation light is not irradiated. It is a value (ΔR / R) divided by the reflectance R when the semiconductor region is not irradiated with excitation light. Such a change in the reflectance of the measurement light is considered to be caused by the following action. In general, when a semiconductor is irradiated with light, the number of carriers is increased by being excited by the light, and thereafter, when the carriers return to the original energy level, the light is emitted and disappears. As the number of carriers changes, the electric field strength increases or decreases. Therefore, the reflection intensity of the measurement light differs between when the excitation light is irradiated and when the excitation light is not irradiated. When the structure of the semiconductor region is a complete crystal state, the change rate of the reflectance changes depending on the wavelength of the measurement light. In other words, the spectrum in which the change rate of the reflectance of the measurement light is plotted for each wavelength of the measurement light is a characteristic corresponding to the energy gap that is the difference between the bottom of the conduction band and the top of the valence band of the semiconductor constituting the semiconductor region. Change characteristics.
[0157]
  FIG. 22 shows an example. That is, the reflectance change rate (ΔR / R) shows a minimum value (extreme value) in a wavelength region corresponding to an energy of about 3.3 eV, and the reflectivity changes in a wavelength region where the energy corresponds to 3.5 eV. The change rate (ΔR / R) indicates the maximum value (extreme value). Of the extreme values of the reflectance change rate (ΔR / R), the minimum value has a larger absolute value than the maximum value.
[0158]
  However, if there are many structural disturbances such as crystallographic defects and deviation of the electronic structure from the normal state in the semiconductor, a trap level having a low energy level exists in that region. Then, since the low energy level region generated by such structural disturbance functions as a carrier trapping layer, the amount of increase in the number of carriers is reduced, and the difference in electric field strength is reduced. Therefore, when the depth of the region in which the structure in the semiconductor region is disturbed due to the implantation of impurity ions and the degree of the disorder are large, the change rate (ΔR / R) of the reflectance of the measurement light is small, and the structure is largely disturbed. Hardly changes the reflectance of the measurement light due to the irradiation of the excitation light. That is, in such a case, the spectrum obtained by plotting the change ratio of the reflectance of the measurement light for each wavelength of the measurement light only shows a substantially constant small value.
[0159]
  From the above, it is possible to obtain information on the degree of recovery of the semiconductor region in the annealing process after the implantation of impurity ions by monitoring the change rate of the reflectance of the measurement light.
[0160]
  Next, with reference to FIG. 19 and FIG. 20, the change with time of the spectrum of the change ratio of the reflectance of the probe light in the annealing process after ion implantation will be described.
[0161]
  FIG. 19 is a spectrum diagram showing the relationship between the value of energy proportional to the reciprocal of the wavelength λ of the probe light and the reflectance change rate (ΔR / R). However, since the horizontal axis in FIG. 19 is essentially nothing but the wavelength of the measurement light continuously changed, FIG. 19 shows the spectrum of the reflectance change rate (ΔR / R) with respect to the wavelength change. Is shown. In the present embodiment, since the intensity of the probe light 618 to be irradiated is constant, the intensity difference ΔR of the reflected probe light 619 when the excitation light 620 is irradiated and not irradiated is the intensity R when the excitation light 620 is not irradiated. By dividing, the change rate (ΔR / R) of the reflectance is calculated. Note that the reflectance change rate (ΔR / R) in FIG. 19 is a relative value in which the initial state is zero.
[0162]
  In the state before the heat treatment step is started, the dose amount is about 1 × 10 6 in the n-type semiconductor region 101 on the wafer 103 accommodated in the reaction vessel 607 in the impurity ion implantation process.¹⁵cm^-2Arsenic (As) is introduced under the condition that the implantation energy is about 35 keV. Spectral line S in FIG.₀Is a spectrum of the reflectance change rate (ΔR / R) immediately after the implantation of impurity ions.
[0163]
  Further, the spectral line S in FIG._TenThe wafer 103 is made N by the apparatus shown in FIG.₂ 19 is a spectrum of reflectance change rate (ΔR / R) when annealed at 900 ° C. for 10 seconds in a gas atmosphere, and the spectrum line S in FIG._{twenty five}Is the spectrum of reflectance change rate (ΔR / R) when annealed for 25 seconds under the same conditions. As shown in the figure, it can be seen that the shape of the spectrum of the reflectance change rate (ΔR / R) changes greatly as the annealing process proceeds. That is, this spectral shape shows the recovery of Si crystallinity by annealing, and as the recovery proceeds, the peak value on the maximum side of the spectral line of the reflectance change rate (ΔR / R) increases upward, and the minimum side It can be seen that the peak value of has moved downward.
[0164]
  Therefore, in the present embodiment, attention is paid to the minimum peak value having a larger change width in the spectrum line, and the degree of recovery in the annealing process after the implantation of impurity ions is monitored by the minimum peak value of the spectrum line. However, as shown in FIG. 19, since the spectral line has a minimum peak value at an energy of about 3.3 eV (wavelength 376 nm), the reflectance at a wavelength corresponding to the energy 3.3 eV of the reflected probe light 619 is obtained. The rate of change is assumed to be the minimum peak value of the spectral line.
[0165]
  FIG. 20 shows the spectrum in the annealing process of the wafer 103 using the apparatus shown in FIG. 18 and assuming that the reflectance change rate at a wavelength corresponding to energy 3.3 eV of the reflected probe light 619 is the minimum peak value of the spectrum line. It is a figure which shows the time-dependent change of the minimum peak value of a line. As shown in the figure, the recovery of the crystallinity of the semiconductor region proceeds with the lapse of time of the annealing process, so that the minimum peak value increases with time. It was confirmed by Raman spectroscopy that the crystallinity of the semiconductor region (Si crystal in this embodiment) was sufficiently recovered even when the annealing process was finished when the minimum peak value became -12.0 (35 seconds). did it.
[0166]
  Therefore, in this embodiment, the annealing process is not performed by the change of the minimum peak value in the spectrum line in the actual annealing process based on the experiment performed on the monitor wafer in advance instead of the annealing process time determined with a certain margin. By controlling, it is possible to realize device manufacture having a stable impurity profile as well as a stable crystallinity. That is, by monitoring the reflectance change rate (ΔR / R) at a specific wavelength (energy region) during the annealing process, it is possible to realize a device process having a stable annealing process and good characteristics.
[0167]
  Furthermore, in the present embodiment, the time required for the minimum peak value to become -12.0 is managed, and when the time exceeds 40 seconds, regular maintenance of the heat treatment apparatus is performed. FIG. 23 shows the change in the annealing time until the minimum peak value of the spectral line becomes −12.0 with respect to the number of processed wafers. As described above, the time until the minimum peak value reaches −12.0 according to the number of processed wafers is considered to be due to the deterioration of the component parts of the apparatus. In the conventional management method, troubles such as defective contact resistance in the semiconductor region occurred when annealing exceeding 40 seconds was performed. However, according to the management method of the present invention, such troubles occur. Can be suppressed. In other words, by integrating the optical management method and the process time management method of this embodiment, it is possible to realize process management of the heat treatment process, which was difficult with the conventional method, and thus achieve stable operation. Can do.
[0168]
  In the sixth embodiment, instead of the optical monitor system shown in FIG. 18, the optical monitor system shown in FIG. 8 in the second embodiment or the optical monitor shown in FIG. 9 in the third embodiment. The system, the optical monitoring system shown in FIG. 12 in the fourth embodiment, the optical monitoring system shown in FIG. 14 in the fifth embodiment, and the like can be used.
[0169]
    (Seventh embodiment)
  Next, a second embodiment relating to the impurity concentration measuring method will be described.
[0170]
  In this embodiment, the optical monitor system shown in FIG. 8 used in the second embodiment is used.
[0171]
  However, in this embodiment, the excitation light 511 is chopped by the chopper 510 at a frequency of 100 Hz and is intermittently irradiated to the n-type semiconductor region 103 a of the wafer 103. Data relating to the reflection intensity measured by the observation system / analysis system 509 is sent to a heat treatment control system (not shown) via a signal line. Further, the chopper 510 and the detector that detects the intensity of the reflected probe light are configured to operate in synchronization.
[0172]
  FIG. 21 shows the relationship between the minimum peak value in the spectral line of the reflectance change rate obtained by actual observation and the impurity dose at the time of impurity introduction. The impurity is arsenic (As), and the dose amount tested is 1.0 × 10¹⁵cm^-2, 5.0 × 10¹⁵cm^-2, 5.0 × 10¹⁴cm^-21.0 × 10¹⁴cm^-2In any case, the acceleration energy of ions is 150 keV. The heat treatment is N₂In a gas atmosphere, 850C is performed for 1 hour. In FIG. 22, the dose is 1.0 × 10¹⁵cm^-2The spectrum of the reflectance change rate (ΔR / R) in the case of is shown.
[0173]
  As can be seen from FIG. 21, it can be seen that the minimum peak value of the reflectance change rate (ΔR / R) of the sample into which the impurity is introduced increases toward the negative side as the dose increases. That is, the reflectance change rate (ΔR / R) reflects the impurity concentration. By monitoring the reflectance change rate (ΔR / R), the final impurity concentration in the substrate after the heat treatment can be determined. It means that you can know. Therefore, the impurity concentration in the n-type semiconductor region 101 can be accurately controlled by performing ion implantation of impurities and heat treatment for diffusion until the minimum peak value reaches a certain value.
[0174]
  In the sixth and seventh embodiments, the heat treatment process for recovering the disorder of the structure caused by the defects caused by the implantation of impurity ions has been described. However, the heat treatment of the present invention is limited to such an embodiment. However, the present invention is also applied to a heat treatment process for recovering structural disturbance caused by defects caused by etching.
[0175]
  In the seventh embodiment, instead of the optical monitor system shown in FIG. 8, the optical monitor system shown in FIG. 9 in the third embodiment or the optical monitor shown in FIG. 12 in the fourth embodiment. The system, the optical monitoring system shown in FIG. 14 in the fifth embodiment, or the like can be used.
[0176]
    (Eighth embodiment)
  Hereinafter, an optical evaluation apparatus and evaluation method for a semiconductor device (insulating film) according to the eighth embodiment will be described with reference to FIGS.
[0177]
  FIG. 24 is a perspective view schematically showing a configuration of an optical monitoring system for an insulating film according to the present embodiment. In FIG. 24, 701 is a wafer-like semiconductor substrate on which a silicon oxide film is formed, 702 is a wafer stage, 703 is a Xe lamp as a second light source with an output of 150 W, 704 is a polarizer, and 705 is an analyzer. Detector, 706 is probe light (measurement light) which is Xe lamp light, 707 is reflected probe light, 708 is a signal line for transmitting a signal from the detector 705, and 709 is a first light source having an output of 5 W. A certain Ar ion laser, 710 is a chopper for modulating pump light, 711 is pump light that is pump light modulated by the chopper 710, 712 is a signal line for transmitting a synchronization signal with modulation of the pump light, 713 Indicates a control system, respectively. The detector 705 is configured to measure a continuous spectrum of the reflected probe light 707 for each wavelength. In addition, the excitation light 711 is chopped by the chopper 710 at a frequency of 500 Hz, and is configured to be intermittently irradiated onto the measurement region of the semiconductor substrate 701 from a direction perpendicular to the surface of the semiconductor substrate 701. Further, the chopper 710 and the detector 705 that detects the intensity of the reflected light are configured to operate in synchronization.
[0178]
  On the other hand, as shown in FIG. 25, a silicon oxide film 701c is formed on the n-type semiconductor region 701b of the semiconductor substrate 701, which is a region to be measured, by a thermal oxidation method at a temperature of 850 ° C., for example. The probe light 706 passes through the silicon oxide film 701c, is incident on the n-type semiconductor region 701b immediately below, and is reflected on the surface of the n-type semiconductor region 701b. The reflected probe light 707 is emitted outward through the silicon oxide film 701c.
[0179]
  However, although not shown in FIG. 24, for example, a chamber for performing thermal oxidation similar to the structure shown in FIG. 18 is arranged, and the wafer stage 702 is installed in this chamber, and a probe is provided in the chamber. A window for allowing the light 706, the reflected probe light 707, and the excitation light 711 to pass therethrough is provided.
[0180]
  Here, a basic principle of the light modulation reflectance spectroscopy and a method for measuring the change rate (ΔR / R) of the reflection intensity of the reflected probe light 707 according to the present embodiment will be described.
[0181]
  In general, when a semiconductor is irradiated with light, the number of carriers is increased by being excited by the light, and thereafter, when the carriers return to the original energy level, the light is emitted and disappears. As the number of carriers changes, the surface electric field strength of the semiconductor region changes. Therefore, the ratio at which the measurement light is reflected on the surface of the semiconductor region, that is, the reflectance of the measurement light is different between when the excitation light is irradiated and when the excitation light is not irradiated. That is, if the magnitude of the change in the electric field strength to be generated by the irradiation of the excitation light changes depending on some characteristic of the measurement region, the ratio of the measurement region is measured by measuring the change rate of the reflectance of the measurement light. It should be possible to evaluate the properties. The present invention is premised on such a technique of light modulation reflectance spectroscopy.
[0182]
  Therefore, in the present embodiment, first, the silicon oxide film 701c of the semiconductor substrate 701 that is the measurement target region is passed, and the n-type semiconductor region 701b immediately below it is intermittently irradiated with the excitation light 711 from another direction. The probe light 706 is continuously passed through the silicon oxide film 701 c and irradiated to the n-type semiconductor region 701 b immediately below the probe light 706 to detect a change in the reflection intensity of the reflected probe light 707. Then, the difference ΔR in the reflection intensity of the reflected probe light 707 when the excitation light 711 is irradiated and when it is not irradiated is divided by the reflection intensity R when the excitation light 711 is not irradiated (ΔR / R) is detected by the analysis system 713 as the change rate of the reflection intensity. Here, the change rate (ΔR / R) of the reflection intensity is used in place of the reflectance on the assumption that the intensity of the irradiated probe light 706 is constant, and is technically meaningful. There is a change rate of reflectance. With the above configuration, the change in the change rate of the reflection intensity of the probe light is monitored. Then, on the display of the analysis system 713 shown in FIG. 24, the spectrum of the change rate (ΔR / R) of the reflection intensity of the measurement light as shown is displayed.
[0183]
  FIG. 26 shows a spectrum of the change rate (ΔR / R) of the reflection intensity measured by the detector 705. In the figure, a curve Spa shows a spectrum of a change rate (ΔR / R) of reflection intensity from a semiconductor substrate having a normal silicon oxide film, and curves Spb and Spc are reflections from a semiconductor substrate having a defective silicon oxide film. The spectrum of intensity change rate (ΔR / R) is shown. Because of the difference in the spectrum shape of the reflection intensity change rate (ΔR / R), the reflection intensity change rate (ΔR / R) of a non-defective semiconductor substrate is within a certain range (the region indicated by the hatched area in the figure). It was found that the ratio of change in reflection intensity (ΔR / R) from a semiconductor substrate having a defective silicon oxide film is so large that it falls out of this range. The cause of such a difference is considered to be due to the following actions.
[0184]
  As shown in FIG. 27A, when an excitation light 711 is irradiated on the n-type semiconductor region directly below the silicon oxide film, carriers are generated in the n-type semiconductor region. The intensity increases by ΔΦ. As described above, the occurrence of the change ΔΦ in the surface electric field strength causes the reflection intensity to be different between when the excitation light is irradiated and when it is not irradiated. Here, when a silicon oxide film is formed on the n-type semiconductor region, a defect site serving as a carrier trap is generated in the surface layer of the n-type semiconductor region, so that the change in the reflectance of the measurement light is small. Should be.
[0185]
  However, as shown in FIG. 27B, if trap electrons are present in the silicon oxide film, the electrons cause a larger change in surface electric field intensity ΔΦ ′ in the n-type semiconductor region. For this reason, the change rate (ΔR / R) of the reflection intensity from the n-type semiconductor region immediately below the silicon oxide film in which many trapped electrons are present is the reflection from the n-type semiconductor region immediately below the silicon oxide film having few trapped electrons. It is considered that it becomes larger than the intensity change rate (ΔR / R). That is, a large number of trapped electrons exist in the silicon oxide film of the semiconductor substrate that gives the spectra Spb and Spc having a large reflection intensity change rate (ΔR / R) as shown in FIG. It is known that such trap electrons exist as the number of defects in the silicon oxide film increases. It is also known that when a large number of trapped electrons are present, a carrier path due to dielectric breakdown is likely to occur, and the life of the insulating film is short.
[0186]
  Therefore, in order to support the above inference, the inventor conducted an experiment in which an electrical stress was applied to a silicon oxide film having a thickness of about 2 to 4 nm in various sizes to obtain data shown in FIG. It was. FIG. 28 is a diagram showing the relationship between the peak intensity in the spectrum of the reflection intensity change rate (ΔR / R) and the trap electron density in each oxide film obtained by measuring the capacity with a mercury probe. In the figure, the vertical axis represents the trap electron density (× 10¹¹cm²The horizontal axis represents the relative value of the peak signal intensity that gives the minimum peak value near 3.35 eV (corresponding to the vicinity of the wavelength of 375 nm) in the spectrum of the reflection intensity change rate (ΔR / R). As shown in FIG. 28, since the trap electron density increases as the absolute value of the peak signal intensity increases, when the absolute value of the change rate (ΔR / R) of the reflection intensity is larger than a certain range, the silicon oxide film It can be evaluated that the quality of is not good (that is, there are many trapped electrons).
[0187]
  That is, if the change rate (ΔR / R) (absolute value) of the reflection intensity is equal to or greater than a predetermined value, the gate oxide film is determined to be defective regardless of whether the above reasoning is theoretically correct. It is consistent with the causal relationship obtained empirically. Therefore, by monitoring the rate of change in reflection intensity (ΔR / R), the amount of electron traps in the insulating film can be specified, so that the electrical characteristics of the insulating film can be managed optically.
[0188]
  Next, an example in which process management in manufacturing a semiconductor device is performed by such optical evaluation will be described.
[0189]
  As shown in FIG. 29, the peak value in the spectrum of the reflection intensity change rate (ΔR / R) is −0.25 to 0.25 × 10 6.^-3If it falls within this range, it is considered as a non-defective product. Conversely, if it does not fall within this range, it is set as defective, and process control was performed when a silicon oxide film was prototyped on a semiconductor substrate (wafer) by thermal oxidation. . In FIG. 29, the horizontal axis represents the number of processed sheets, and the vertical axis represents the change rate (ΔR / R) (peak value) of the reflection intensity in the vicinity of 3.35 eV. As a result of monitoring once every 125 sheets, the signal suddenly changed greatly at the 750th sheet. This is a sudden trouble. The characteristic of the gate oxide film at this time is that when the applied voltage Vg to the gate is −6.6 V, the time tbd (lifetime value) until the breakdown showing reliability is 100 sec. It was about. The normal lifetime value tbd is 10^FourSince it is sec or more, it can be seen that this lifetime value is an abnormally low value. In this case, the cause of the trouble can be removed by the quick response to the trouble, and the subsequent occurrence of defects can be prevented. In this way, in the present invention, by managing the manufacturing process by optical characteristic evaluation, it is possible to respond more quickly than the management by the conventional evaluation of electrical characteristics, and the sample prototyping process and MOS device manufacturing can be performed. It is possible to reliably prevent the yield in the process from deteriorating.
[0190]
  In addition, by conducting an experiment in advance, the relationship between the appropriate range of capacitance (electrical characteristics) corresponding to an appropriate electron trap density and the appropriate range of the change rate of reflection intensity (ΔR / R) corresponding to this appropriate range is shown. If obtained, the manufacturing conditions can be controlled so that the change rate (ΔR / R) of the reflection intensity falls within an appropriate range.
[0191]
  In this embodiment, instead of the optical monitoring system shown in FIG. 24, the optical monitoring system shown in FIG. 8 in the second embodiment, the optical monitoring system shown in FIG. 9 in the third embodiment, The optical monitor system shown in FIG. 12 in the fourth embodiment, the optical monitor system shown in FIG. 14 in the fifth embodiment, or the like can be used.
[0192]
  In the optical monitoring system according to this embodiment, the semiconductor region is irradiated with measurement light having a wavelength range of 600 nm or less, more preferably 300 to 600 nm, by selecting a light source for measurement light or by attaching a filter. It is preferable. The light having such a wavelength range does not have a penetration depth of several tens of nanometers or more into the semiconductor region. Optical evaluation with high sensitivity can be performed.
[0193]
    (Ninth embodiment)
  Next, a ninth embodiment will be described. 30A to 30C are cross-sectional views of the wafer showing the patterning process of the gate electrode and the gate oxide film. However, in this embodiment, the gate electrode and the gate oxide film are patterned using the etching apparatus shown in FIG. 4 in the first embodiment.
[0194]
  First, before the step shown in FIG. 30A, a first semiconductor region 800 into which a low concentration impurity for threshold control is introduced is provided in the substrate region of the chip region Rtp on the wafer 803. In addition, a MOS transistor which is a semiconductor element is formed in the first semiconductor region 800. On the other hand, the monitor region Rmn on the wafer 803 has a size of, for example, 13 × 13 μm.²A second semiconductor region 801 (having a specific resistance value of about 0.02 Ωcm) into which the n-type impurity is introduced is formed. A gate oxide film 807 having a thickness of, for example, 6 nm and a gate electrode film 806 made of polysilicon are deposited on the entire surface of the substrate. Further, a photoresist mask 809 having a pattern shape for forming a gate electrode is formed on the gate electrode film 806. However, the photoresist mask 809 also has an opening region above the second semiconductor region 801.
[0195]
  Next, in the step shown in FIG. 30B, the gate electrode film 806 is removed by dry etching (plasma etching) using the photoresist mask 809, and a gate electrode 806a is formed. At this time, the gate electrode film in the second semiconductor region 801 is removed, and the gate oxide film 807 is exposed.
[0196]
  In this state, the excitation light 402 and the probe light 403 are irradiated to the second semiconductor region 801 through the gate oxide film 807. However, the excitation light 402 is irradiated intermittently. Then, as described above, a value obtained by dividing the reflection intensity difference ΔR of the probe light 403 when the excitation light 402 is irradiated and not irradiated by the reflection intensity R when the excitation light 402 is not irradiated ( ΔR / R) is detected by the reflection intensity observation system 220 shown in FIG. 4 as a change rate of the reflection intensity. With the above configuration, the change in the change rate of the reflection intensity is monitored.
[0197]
  Next, in the step shown in FIG. 30C, the patterning of the gate oxide film 807 is completed, and the gate oxide film 807a is left immediately below the gate electrode 806a. Here, in this embodiment, when the etching is completed in this way, the change rate (ΔR / R) of the reflectance of the probe light in the second semiconductor region 801 is greater than the value shown in FIG. Note that there is a big change.
[0198]
  FIG. 31 is a spectrum diagram showing the change rate (ΔR / R) of the reflectance of the probe light when the gate oxide film is removed. When the gate oxide film is present as shown in FIG. 30B, the spectral line has a large absolute value due to the presence of trapped electrons in the gate oxide film. It changes so as to show a spectral line having a small absolute value (for example, a spectral line Slow shown in FIG. 31). As the gate oxide film is further removed, the number of trapped electrons becomes extremely small, and the silicon substrate has almost no damaged layer, so that the absolute value of the peak value increases. Then, when the removal of the gate oxide film shown in FIG. 30C is completed, a spectral line Shigh having a large peak value is shown. Therefore, by continuously monitoring the change ratio (ΔR / R) of the reflectance of the probe light, it is possible to detect the time when the gate oxide film is completely removed while the substrate is hardly damaged. That is, the dry etching process can be controlled so that the etching is stopped when the removal of the gate oxide film is completed, and damage to the silicon substrate can be minimized.
[0199]
  However, the control method of the etching process of the present embodiment is not only the removal of the gate oxide film, but the etching for removing other insulating films as long as the insulating film is not thick enough to obtain the measurement sensitivity effectively. It can also be applied to.
[0200]
    (Tenth embodiment)
  Next, a tenth embodiment will be described. In this embodiment, although illustration of the wafer is omitted, for example, in the state shown in FIG. 30C of the ninth embodiment, impurity introduction for forming source / drain regions in the first semiconductor region 800 is performed. It is applicable to the process to be performed.
[0201]
  In FIG. 32, the change rate (ΔR / R) of the reflectance of the probe light was monitored in the process of introducing impurities into the semiconductor region by plasma doping using a mixed gas of BF 2 and He at a pressure of 10 mTorr. It is a figure which shows a result. In the figure, the horizontal axis represents the processing time, and the vertical axis represents the absolute value of the signal intensity (relative value) of the minimum peak value. As shown in the figure, the signal intensity decreases as the impurities are introduced, and it is understood that defects are generated in the semiconductor region due to the introduction of the impurities. Therefore, when the change ratio (ΔR / R) of the reflectance of the probe light is reduced by a predetermined value or a predetermined ratio from the initial value, introduction of impurities is stopped, or an experiment is performed in advance to cope with a desired impurity concentration. Impurities with a desired concentration can be introduced by obtaining a signal intensity and performing control such as stopping the introduction of impurities when the signal intensity is reached.
[0202]
  Further, if the heat treatment is performed after the introduction of the impurity by plasma doping or ion implantation, and the light modulation reflectance measurement is performed after the heat treatment to evaluate the change rate (ΔR / R) of the reflectance of the measurement light, the impurity after the heat treatment You can see the concentration of. Accordingly, it is possible to determine in advance impurity introduction conditions (for example, ion implantation amount, ion implantation energy, high-frequency power during plasma doping, etc.) for realizing an appropriate impurity concentration by conducting preliminary experiments. In particular, if the in-line light modulation reflectivity measurement is performed on the semiconductor region before introducing the impurity and the concentration of the impurity in the semiconductor region in the process is grasped, the impurity can be introduced with higher accuracy.
[0203]
  However, also in the present embodiment, a monitor region for optical evaluation can be provided in a region different from the region where the semiconductor element is formed.
[0204]
    (Other embodiments)
  In the optical monitor system in each of the above embodiments, the Xe lamp, the polarizer, the detector, and the like use the members of the ellipsometry spectrometer that are currently used for measuring the thickness of the oxide film as they are. Can do. In that case, the optical evaluation of the present invention can be performed only by newly providing an Ar ion laser, a chopper, and a control system.
[0205]
  In each of the above embodiments, the case where a MOS transistor is formed has been described as an example. However, the present invention can also be applied to the case where a device such as a bipolar transistor or a MESFET formed on a compound semiconductor substrate is formed.
[0206]
【The invention's effect】
  Claim 1To 3 or 4 to 5According to the present invention, as an optical evaluation device used when processing a substrate having a semiconductor region in a chamber, a configuration for calculating a rate of change in reflectance of measurement light from the semiconductor region by light modulation reflectance measurement and Therefore, it is possible to perform in-line evaluation when controlling the conditions of processing performed in the chamber, using information obtained from the reflectance change ratio reflecting the crystal state of the semiconductor region.
[0207]
  Claim6 to 17According to the present invention, as an optical evaluation apparatus for evaluating the electrical characteristics of the insulating film on the semiconductor region, the reflectance change rate of the measurement light from the semiconductor region is calculated by light modulation reflectance measurement, and this reflection is calculated. Since the electrical characteristics of the insulating film are evaluated based on the rate of change in rate, information on electrical defects in the insulating film such as the gate oxide film can be obtained, and the insulating film can be quickly and reliably It can be used for management of electrical characteristics.
[0208]
  Claim18 to 21According to the present invention, in the semiconductor device manufacturing apparatus for processing the semiconductor region in the chamber, the function of the optical evaluation apparatus as described above is added, and the processing conditions are controlled based on the reflectance change rate. Since it did in this way, the conditions of the processing process performed in a chamber can be controlled based on in-line evaluation, Therefore The semiconductor device which has a desired characteristic can be formed with sufficient reproducibility.
[0209]
  Claim22 to 27According to the present invention, as an optical evaluation method for evaluating the state of processing when processing is performed in the chamber, the change rate of the reflectance of the measurement light from the semiconductor region is calculated by light modulation reflectance measurement. Therefore, it is possible to provide an in-line optical evaluation method for controlling the processing conditions by using the change ratio of the reflectance of the measurement light reflecting the crystal state of the semiconductor region.
[0210]
  Claim28 to 40According to the method of managing a semiconductor device manufacturing apparatus that performs light modulation reflectance measurement as described above in a chamber, while the substrate is processed in the chamber, the change rate of the reflectance of the measurement light is a predetermined value. Since the device is maintained when the predetermined time until it reaches the limit and the predetermined time exceeds the limit value, it is possible to detect the deterioration of the components in the chamber and perform maintenance at an appropriate timing. Therefore, it is possible to avoid the occurrence of defects in the semiconductor region due to excessive processing time.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a method for manufacturing a semiconductor device according to an embodiment.
FIG. 2 is a cross-sectional view of the wafer showing the manufacturing process of the semiconductor device according to the embodiment.
FIG. 3 is a top view of a wafer according to the embodiment.
FIG. 4 is a cross-sectional view of a plasma processing apparatus which is a semiconductor device manufacturing apparatus according to an embodiment.
FIG. 5 is a characteristic diagram showing the relationship between the etching time and the change rate of the reflection intensity of the probe light in the embodiment.
FIG. 6 is a characteristic diagram showing a relationship between etching time and contact resistance in the embodiment.
7 is a diagram showing a difference in contact resistance value variation of a semiconductor device formed by using the light etching method of the embodiment and the conventional light etching method, respectively. FIG.
FIG. 8 is a perspective view schematically showing an optical monitor system of a semiconductor device according to a second embodiment.
FIG. 9 is a cross-sectional view of a wafer showing a manufacturing process of a semiconductor device according to a second embodiment.
FIG. 10 is data showing a difference in excitation light intensity-probe light reflectance change characteristics between a sample subjected to the plasma treatment of the second embodiment and a sample not subjected to the plasma treatment.
FIG. 11 is a perspective view schematically showing an optical monitor system of a semiconductor device according to a third embodiment.
FIG. 12 is a perspective view schematically showing an optical monitor system of a semiconductor device according to a fourth embodiment.
FIG. 13 is a graph in which the change rate of the reflection intensity of the probe light when light etching is performed for 20 seconds using the optical monitor system of the fourth embodiment is plotted by changing the RF power.
FIG. 14 is a perspective view schematically showing an optical monitor system of a semiconductor device according to a fifth embodiment.
FIG. 15 is a diagram in which the change rate of the reflection intensity of the probe light when light etching is performed for 20 seconds using the optical monitor system of the fifth embodiment is plotted by changing the RF power.
FIG. 16 is a characteristic diagram showing the relationship between the etching time and the change rate of the reflection intensity of the probe light in the fifth embodiment.
FIG. 17 is a cross-sectional view schematically showing a state in which the optical monitoring system of the third to fifth embodiments is attached to a plasma processing apparatus.
FIG. 18 is a cross-sectional view schematically showing a configuration of a semiconductor heat treatment apparatus according to a sixth embodiment.
FIG. 19 is a spectrum diagram showing a change in the spectrum shape of the reflectance change rate with the annealing time in the sixth embodiment.
FIG. 20 is a diagram showing a change in the minimum peak value with respect to the annealing time in the sixth embodiment.
FIG. 21 is a diagram showing a relationship between a dose amount and a minimum peak value during ion implantation in the seventh embodiment.
FIG. 22: Arsenic ion dose amount 1 × 10¹⁵cm^-2It is a spectrum diagram of the change rate of the reflectance after introduce | transducing and heat-processing.
FIG. 23 is a diagram showing a change with respect to the number of wafers to be processed of a required time until the minimum peak value during the heat treatment reaches a predetermined value in the sixth embodiment.
FIG. 24 is a block diagram partially showing a configuration of an optical evaluation apparatus according to an eighth embodiment in a perspective view.
FIG. 25 is a cross-sectional view showing the structure of an object to be measured used for performing optical evaluation in the eighth embodiment.
FIG. 26 is a spectrum diagram of a signal related to a change rate of reflection intensity from a semiconductor region of probe light in the eighth embodiment.
FIG. 27 is an energy band diagram in the silicon oxide film and the n-type semiconductor region when irradiated with the excitation light, and an energy band diagram in the silicon oxide film and the n-type semiconductor region when not irradiated with the excitation light.
FIG. 28 is a diagram showing the relationship between the peak intensity in the spectrum of the change ratio of the reflection intensity of the probe light and the density of trapped electrons in the oxide film.
FIG. 29 is a diagram showing the relationship between the number of wafers processed and the rate of change in reflection intensity near 3.35 eV when optical evaluation is used to manage the oxidation process of a prototype using the eighth embodiment. is there.
FIG. 30 is a cross-sectional view of a wafer showing the manufacturing steps of the semiconductor device according to the ninth embodiment.
FIG. 31 is a spectral diagram showing a change in the change ratio of the reflectance of measurement light in the ninth embodiment.
32 is a diagram showing the relationship between the plasma doping processing time and the peak intensity of the change ratio of the reflectance of measurement light in the tenth embodiment. FIG.
[Explanation of symbols]
  101 n-type semiconductor region
  103 wafers
  104 Interlayer insulation film
  105 photoresist mask
  106 Gate electrode
  107 Gate oxide film
  108 n-type source region
  109 n-type drain region
  110a-c opening
  200 Reaction processing chamber
  211 High frequency power supply
  212 Coupling capacitor
  213 Anode electrode
  214 Cathode electrode
  215 Endpoint detection window
  216 End point detection system
  217 mirror
  218 Probe light entrance window
  219 Reflected light observation window
  220 Reflection intensity observation system
  221 Signal path
  222 Etching control system
  223 Chopper
  301 Ar ion laser (first light source)
  302 Xe lamp (second light source)
  401 Plasma
  402 Excitation light
  403 Probe light
  404 Reflective probe light
  502 Xe lamp (second light source)
  503 Ar ion laser (first light source)
  504 Wafer stage
  505 Microscope system
  506 Mirror
  507 Probe light
  508 Reflected probe light
  509 Observation system and analysis system
  510 chopper
  511 excitation light
  512 reflected excitation light
  513 Reflected excitation light observation system
  525 filter
  530 Optical system
  701 Semiconductor substrate
  701a body
  701b n-type semiconductor region
  701c Silicon oxide film
  702 Wafer stage
  703 Xe lamp (second light source)
  704 Polarizer
  705 detector
  706 Probe light
  707 Reflected probe light
  708 signal line
  709 Ar ion laser (first light source)
  710 chopper
  711 Excitation light
  712 signal line
  713 Control and analysis system
  Rtp chip area
  Rmn monitor area
  Rdm1-3 damage layer

Claims (40)

An optical evaluation device used when processing a substrate having a semiconductor region in a chamber,
A first light source that generates excitation light;
A second light source for generating measurement light;
A first light guide member for intermittently irradiating the semiconductor region of the semiconductor substrate in the chamber with the excitation light generated by the first light source;
A second light guide member for irradiating the semiconductor region with the measurement light generated by the second light source;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
A third light guide member for causing the measurement light reflected from the semiconductor region to enter the reflectance detection means;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated A change calculation means for calculating a value obtained by dividing the measurement light reflectance by a change ratio of the measurement light reflectance;
Equipped with a,
The first light source and the second light source are composed of a single common light source that generates a broad spectrum light having a wavelength including the wavelengths of the excitation light and the measurement light,
A beam splitter that separates the broad spectrum light generated by the common light source into excitation light and measurement light;
A spectroscopic unit that receives the measurement light reflected from the semiconductor region, splits the measurement light, and sends the measurement light to the reflectance detection unit;
The optical evaluation apparatus, wherein the first and second light guiding members are arranged at positions to receive light from the beam splitter . The optical evaluation apparatus according to claim 1,
It said second light guide member, optical evaluation device, characterized in that the measurement light is configured to be incident from the vertical direction to the surface of the substrate. The optical evaluation apparatus according to claim 2,
The first light guide member, optical evaluation device, characterized in that the excitation light is configured to be incident from the vertical direction to the surface of the substrate. An optical evaluation apparatus used when processing a substrate having a semiconductor region in a chamber,
A first light source that generates excitation light;
A second light source for generating measurement light;
A first light guide member for intermittently irradiating the semiconductor region of the semiconductor substrate in the chamber with the excitation light generated by the first light source;
A second light guide member for irradiating the semiconductor region with the measurement light generated by the second light source;
A reflectance detection means for detecting the reflectance of the measurement light applied to the semiconductor region;
A third light guide member for causing the measurement light reflected from the semiconductor region to enter the reflectance detection means;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated A change calculation means for calculating a value obtained by dividing the measurement light reflectance by a change ratio of the measurement light reflectance;
With
The change computing means, optical evaluation device for calculating only the change rate of the reflectance of the measurement light at a specific energy value of the measurement light giving the extreme value each spectrum odor change rate of the reflectance of the measurement light. The optical evaluation device according to claim 4 ,
The specific energy value of the measurement light is any value included in a range of 3.2 to 3.6 eV. An optical evaluation apparatus for evaluating electrical characteristics of an insulating film formed on a semiconductor region of a substrate,
A first light source that generates excitation light;
A second light source for generating measurement light;
A first light guide member for intermittently irradiating the semiconductor region directly below the excitation light generated by the first light source through the insulating film;
A second light guide member for irradiating measurement light generated by the second light source to a semiconductor region through which the excitation light is intermittently irradiated through the insulating film;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
A third light guide member for causing the measurement light reflected from the semiconductor region to enter the reflectance detection means;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated The change calculation means for calculating the change rate of the reflectivity of the measurement light by dividing by the reflectivity of the measurement light,
An optical evaluation apparatus comprising: evaluation means for evaluating the electrical characteristics of the insulating film based on the change rate of the reflectance of the measurement light. The optical evaluation apparatus according to claim 6 , wherein
The evaluation unit, the value change rate of the reflectance of the measurement light at a specific energy value of the measurement light giving the extreme value each spectrum odor change rate of the reflectance of the measurement light, corresponding to the proper capacitance of the insulating film An optical evaluation apparatus characterized in that it is determined as a non-defective product only when The optical evaluation apparatus according to claim 6 , wherein
The specific energy value of the measurement light is any value included in a range of 3.2 to 3.6 eV. In the optical evaluation device according to any one of claims 6 to 8 ,
An optical evaluation apparatus, further comprising a spectroscopic unit that receives the measurement light reflected from the semiconductor region, splits the measurement light, and sends the measurement light to the reflectance detection unit. In the optical evaluation device according to any one of claims 6 to 8 ,
A filter for receiving measurement light reflected from the semiconductor region, transmitting only measurement light in a wavelength range corresponding to a specific energy value of the measurement light, and sending the measurement light to the reflectance detection means; An optical evaluation device. The optical evaluation apparatus according to claim 6 , wherein
The optical evaluation apparatus, wherein the reflectance detection means detects the reflectance of measurement light in a wavelength range of 600 nm or less. The optical evaluation apparatus according to claim 11 .
The optical evaluation apparatus, wherein the reflectance detection means detects the reflectance of measurement light in a wavelength range of 300 to 600 nm. In the optical evaluation device according to any one of claims 6 to 12 ,
An optical evaluation apparatus characterized by being constructed using an ellipsometry spectrometer. In the optical evaluation device according to any one of claims 6 to 13 ,
An optical evaluation apparatus attached to a chamber used for forming an oxide film of a semiconductor device. The optical evaluation apparatus according to claim 6 , wherein
The optical evaluation apparatus, wherein the second light source is an Xe lamp. The optical evaluation apparatus according to claim 6 , wherein
The optical evaluation apparatus, wherein the first light source is an Ar ion laser or a He—Ne laser. In the optical evaluation device according to any one of claims 6 to 16 ,
The optical evaluation apparatus, wherein the first light guide member is configured to intermittently irradiate the excitation light at a frequency of 1 kHz or less. A chamber for housing a substrate having a semiconductor region;
Processing means for processing the substrate in the chamber;
First light supply means for intermittently irradiating the semiconductor region of the substrate installed in the chamber with excitation light;
Second light supply means for irradiating the semiconductor region with measurement light;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated A change calculation means for calculating a value obtained by dividing the measurement light reflectance by a change ratio of the measurement light reflectance;
A processing control means for receiving the output of the change calculation means during the processing of the processing means and controlling the processing conditions based on the reflectance change rate ;
An apparatus for manufacturing a semiconductor device, wherein the processing means generates plasma in the chamber to etch the semiconductor region . A chamber for housing a substrate having a semiconductor region;
Processing means for processing the substrate in the chamber;
First light supply means for intermittently irradiating the semiconductor region of the substrate installed in the chamber with excitation light;
Second light supply means for irradiating the semiconductor region with measurement light;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated A change calculation means for calculating a value obtained by dividing the measurement light reflectance by a change ratio of the measurement light reflectance;
A processing control means for receiving the output of the change calculating means during the processing of the processing means and controlling the processing conditions based on the reflectance change rate;
With
The said processing means is a manufacturing apparatus of the semiconductor device which performs light dry etching for generating the plasma in the said chamber and removing the damage layer produced by the etching of the said semiconductor region. A chamber for housing a substrate having a semiconductor region;
Processing means for processing the substrate in the chamber;
First light supply means for intermittently irradiating the semiconductor region of the substrate installed in the chamber with excitation light;
Second light supply means for irradiating the semiconductor region with measurement light;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
Receiving the output of said reflectance detector, the difference between the measured reflectance of the time when in the semiconductor region the excitation light is irradiated and the excitation light is not irradiated is the excitation light not irradiated Change calculation means for calculating a value obtained by dividing the measurement light reflectance by the change rate of the measurement light reflectance,
A processing control means for receiving the output of the change calculating means during the processing of the processing means and controlling the processing conditions based on the reflectance change rate;
With
The said processing means is a manufacturing apparatus of the semiconductor device which forms a thin insulating film on the said semiconductor region. A chamber for housing a substrate having a semiconductor region;
Processing means for processing the substrate in the chamber;
First light supply means for intermittently irradiating the semiconductor region of the substrate installed in the chamber with excitation light;
Second light supply means for irradiating the semiconductor region with measurement light;
A reflectance detecting means for detecting the reflectance of the measurement light applied to the semiconductor region;
When the output of the reflectance detection means is received, the difference in reflectance of the measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated is when the excitation light is not irradiated A change calculation means for calculating a value obtained by dividing the measurement light reflectance by a change ratio of the measurement light reflectance;
A processing control means for receiving the output of the change calculating means during the processing of the processing means and controlling the processing conditions based on the reflectance change rate;
With
A thin insulating film is formed on the semiconductor region,
The said processing means is a manufacturing apparatus of the semiconductor device which performs the dry etching for removing the said insulating film on the said semiconductor region. An optical evaluation method for evaluating the state of processing when processing a substrate having a semiconductor region in a chamber,
Irradiating the semiconductor region of the substrate in the chamber with measurement light;
Intermittently irradiating the semiconductor region with excitation light;
A value obtained by dividing the difference in reflectance of measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated by the reflectance of measurement light when the excitation light is not irradiated Calculating as a reflectance change rate ,
The optical processing method wherein the processing is plasma etching processing of the semiconductor region . An optical evaluation method for evaluating the state of processing when processing a substrate having a semiconductor region in a chamber,
Irradiating the semiconductor region of the substrate in the chamber with measurement light;
Intermittently irradiating the semiconductor region with excitation light;
A value obtained by dividing the difference in reflectance of measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated by the reflectance of measurement light when the excitation light is not irradiated Calculating the reflectance change rate as
With
The optical evaluation method, wherein the processing is light dry etching for removing a damaged layer caused by plasma etching of the semiconductor region. An optical evaluation method for evaluating the state of processing when processing a substrate having a semiconductor region in a chamber,
Irradiating the semiconductor region of the substrate in the chamber with measurement light;
Intermittently irradiating the semiconductor region with excitation light;
A value obtained by dividing the difference in reflectance of measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated by the reflectance of measurement light when the excitation light is not irradiated Calculating the reflectance change rate as
With
The processing method is an optical evaluation method in which an insulating film is formed on the semiconductor region. An optical evaluation method for evaluating the state of processing when processing a substrate having a semiconductor region in a chamber,
Irradiating the semiconductor region of the substrate in the chamber with measurement light;
Intermittently irradiating the semiconductor region with excitation light;
A value obtained by dividing the difference in reflectance of measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated by the reflectance of measurement light when the excitation light is not irradiated Calculating the reflectance change rate as
With
The optical evaluation method, wherein the processing is dry etching for removing an insulating film on the semiconductor region. In the optical evaluation method according to any one of claims 22 to 25 ,
Above step of irradiating the measuring light, optical evaluation method characterized by irradiating the measuring light from the vertical direction to the surface of the substrate. The optical evaluation method according to claim 26 .
Above step of irradiating the excitation light, optical evaluation method characterized by irradiating the excitation light from the vertical direction to the surface of the substrate. A chamber for housing a substrate having a semiconductor region, a processing means for processing the substrate in the chamber, and intermittent excitation light to the semiconductor region of the substrate installed in the chamber First light supply means for irradiating, second light supply means for irradiating the semiconductor region with measurement light, and reflectance detection means for detecting the reflectance of the measurement light irradiated on the semiconductor region A method of managing a semiconductor device manufacturing apparatus comprising:
A first step of irradiating the semiconductor region with measurement light;
A second step of intermittently irradiating the semiconductor region with excitation light;
A value obtained by dividing the difference in reflectance of measurement light between when the semiconductor region is irradiated with excitation light and when excitation light is not irradiated by the reflectance of measurement light when the excitation light is not irradiated A third step of calculating as a change rate of the reflectance of the measurement light,
A fourth step of controlling the processing means to operate for a predetermined time until the reflectance change ratio calculated in the third step reaches a predetermined value;
And a fifth step of monitoring the predetermined time in the fourth step and outputting a signal for performing maintenance of the semiconductor device manufacturing apparatus when the predetermined time exceeds a limit value. A method for managing a semiconductor device manufacturing apparatus. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
The method for managing a semiconductor device manufacturing apparatus, wherein the processing means performs etching of the semiconductor region by generating plasma in the chamber. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
The method for managing a semiconductor device manufacturing apparatus, wherein the processing means performs dry etching for generating a plasma in the chamber and removing a damaged layer caused by etching of the semiconductor region. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
The method for managing a semiconductor device manufacturing apparatus, wherein the processing means introduces impurities into the semiconductor region. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
The method for managing a semiconductor device manufacturing apparatus, wherein the processing means performs annealing after ion implantation is performed on the semiconductor region. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
The method for managing a semiconductor device manufacturing apparatus, wherein the processing means forms a thin insulating film on the semiconductor region. 29. A method of managing a semiconductor device manufacturing apparatus according to claim 28 .
A thin insulating film is formed on the semiconductor region,
The method for managing a semiconductor device manufacturing apparatus for a semiconductor device, wherein the processing means performs dry etching for removing a thin insulating film on the semiconductor region. In the management method of an apparatus for manufacturing a semiconductor device according to any one of claims 28 34,
The method for managing a semiconductor device manufacturing apparatus, wherein the reflectance detection means detects the reflectance of measurement light in a wavelength range of 600 nm or less. The method of managing a semiconductor device manufacturing apparatus according to claim 35 ,
The method for managing a semiconductor device manufacturing apparatus, wherein the reflectance detection means detects the reflectance of measurement light in a wavelength range of 300 to 600 nm. In the management method of an apparatus for manufacturing a semiconductor device according to any one of claims 28 36,
In the step of computing a rate of change of the reflectance, characterized by calculating a change rate of the reflectance of the measurement light at a specific energy value of the measurement light that gives the extreme value of the spectrum of a change rate of the reflectance of the measurement light A method for managing a semiconductor device manufacturing apparatus. In the management method of an apparatus for manufacturing a semiconductor device according to claims 28 to any one of 37,
The method for managing a semiconductor device manufacturing apparatus, wherein the reflectance detection means is configured to detect the reflectance of reflected light of a specific wavelength using an optical filter. In the management method of the manufacturing apparatus of the semiconductor device as described in any one of Claim 28 to 38 ,
The method for managing a semiconductor device manufacturing apparatus, wherein the semiconductor region is made of n-type silicon. In the management method of an apparatus for manufacturing a semiconductor device according to any one of claims 28 39,
In the step of irradiating the excitation light, the method of managing a semiconductor device manufacturing apparatus, wherein the excitation light is intermittently irradiated at a frequency of 1 kHz or less.

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