JP3164373B2 - Method for evaluating semiconductor layer, method for manufacturing semiconductor device, and recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for optically evaluating the characteristics of an amorphous region in which high-concentration impurity ions are implanted and crystallinity is disturbed, and a temperature measurement and a semiconductor device using the method. The present invention relates to a manufacturing method and a recording medium for automatically performing evaluation.

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device such as a transistor, for example, when forming a source / drain region in a MOSFET or an emitter diffusion layer in a bipolar transistor, a doping amount of an impurity, a depth of a region to be doped, and the like. As a means for accurately controlling the ion implantation, an ion implantation method is used in which ions such as P, As, and B are accelerated and implanted into a semiconductor substrate, a polysilicon layer, or an amorphous silicon film. In recent years, with a demand for miniaturization of a semiconductor device, higher-precision control has been required for an impurity concentration in a region formed by the ion implantation, a thickness of the implantation region, and the like.

For example, it is known that when impurity ions are implanted into a single crystal silicon layer and silicon atoms are repelled from a normal position by the impurity ions, an amorphous region is formed by the recoiled silicon. Conventionally, as a means for measuring the thickness and the like of an amorphous region formed by the recoil silicon ions, RBS (R
utherford Backscattering Spectrometry), TEM
(Transmission electron microscope) cross-sectional photographs and the like.

Further, the ion implantation energy and the ion implantation amount of the impurity ion-implanted on the silicon substrate have been evaluated by a four-terminal sheet resistance measuring method or a thermal wave method.
Similarly, the uniformity of the impurity concentration of an ion-implanted layer formed on a silicon substrate by ion implantation in a silicon wafer has been measured by a four-terminal sheet resistance measurement method or a thermal wave method.

On the other hand, as an optical evaluation method, we tried to obtain information such as complex refractive index and thickness by measuring the elliptical shape of elliptically polarized light reflected from the substrate surface by entering linearly polarized light into the substrate surface in an oblique direction. Ellipsometry is also known as a simple evaluation method.

-Solution problem- However, when these evaluation methods are applied to the evaluation of characteristics in a manufacturing process of an actual semiconductor device, there are the following problems, and the suitability of implantation conditions and the like in a high-concentration ion implantation region is particularly high. Was difficult to evaluate.

First, RBS and TEM are destructive inspection methods and are not suitable for evaluation in a semiconductor device manufacturing line.

In the sheet resistance measurement method, the evaluation of the high-concentration impurity-implanted region is made only by the accelerated diffusion locally due to damage caused by the ion implantation and greatly affected by the heat treatment. Is impossible to evaluate.

In the thermal wave method, the ion implantation energy and ion implantation concentration are measured by measuring the damage of the implantation layer. However, in the region where the high concentration impurity is implanted, the damage amount is the saturation region of the detection sensitivity. Therefore, it is difficult to identify the difference in the injection amount. Also, since the detection value is not an absolute amount but a relative value, high detection sensitivity in a high-concentration injection region cannot be expected.

The present invention has been made in view of the above problems,
The purpose of this method is to evaluate the thickness of an amorphous region in which high-concentration impurity ions have been implanted into a semiconductor layer and thereby disturb the crystallinity, and to evaluate the distribution of the thickness in a substrate surface in a non-destructive manner with good reproducibility. It is an object of the present invention to provide a method for manufacturing a semiconductor device using a layer evaluation method, and a recording medium for causing a computer to execute a semiconductor layer evaluation.

[Disclosure of the Invention] In order to achieve the above object, the measures taken by the present invention include:
An object is to use a parameter relating to a complex refractive index obtained by a spectroscopic ellipsometry method and a spectrum pattern thereof to evaluate a physical quantity of a region into which impurity ions are implanted.

According to the first method for evaluating a semiconductor layer of the present invention, a semiconductor layer having a region into which impurity ions are implanted in a substrate includes:
In the plane perpendicular to the optical axis, the p direction (direction of the line of intersection between the plane perpendicular to the optical axis and the plane containing incident light and reflected light) and the s direction (perpendicular to the p direction in the plane perpendicular to the optical axis) A first step of inputting linearly polarized measurement light inclined with respect to a direction perpendicular to the surface of the semiconductor layer from the direction perpendicular to the surface of the semiconductor layer, and the measurement reflected as elliptically polarized light from the semiconductor layer. A second step of measuring at least cos Δ when a phase difference between the p component and the s component is Δ in the reflected light of the light; and a spectrum of at least cos Δ due to a change in the wavelength of the measurement light. A third step of measuring
a fourth step of detecting the thickness of the amorphous region in the region where the impurity ions are implanted, based on the spectrum of cos Δ, and the relationship between the implantation energy and the thickness of the amorphous region at a specific ion implantation amount. As a first correlation for each ion implantation dose, and a step of preparing in advance a relationship between the spectrum of cos Δ and the implantation energy at a specific ion implantation dose as a second correlation, In the step, after determining the implantation energy of the ions implanted into the semiconductor layer by comparing the spectrum of cos Δ obtained in the second step with the second correlation, the implantation energy is determined by the second energy. Method for measuring the thickness of an amorphous region in the semiconductor layer by comparing with the correlation of (1) A.

The second method for evaluating a semiconductor device of the present invention includes the same basic first to fourth steps as those of the first method, and furthermore, the ion implantation amount and the thickness of the amorphous region at a specific implantation energy. And preparing the relationship between the spectrum of cos Δ at a specific implantation energy and the amount of ion implantation as a second correlation in advance as a first correlation for each implantation energy. In the step, the amount of ions implanted into the semiconductor layer is obtained by comparing the spectrum of cos Δ obtained in the second step with the second correlation, and then the amount of ion implantation is determined. This is a method of measuring the thickness of the amorphous region in the semiconductor layer by comparing the first correlation.

Further, the third method for evaluating a semiconductor device of the present invention includes the same basic first to fourth steps as those of the first method, and further includes the implantation energy and the thickness of the amorphous region at a specific ion implantation amount. Is defined as a first correlation for each ion implantation amount, the wavelength indicating the maximum value of cos Δ in a predetermined wavelength region in the spectrum of cos Δ when the ion implantation amount is kept constant and the implantation energy is changed. The method further comprises a step of preparing a relationship with energy as a second correlation in advance, and in the fourth step, the spectrum of cos Δ obtained in the second step is compared with the second correlation. After determining the implantation energy of the ions implanted into the semiconductor layer by matching, this implantation energy is compared with the first correlation to obtain an upper energy. A method for measuring the thickness of the amorphous region of the semiconductor layer.

The fourth method for evaluating a semiconductor device of the present invention includes the same basic first to fourth steps as those of the first method, and also relates to the relationship between the implantation amount at a specific implantation energy and the thickness of the amorphous region. The first for each injection energy
The correlation between the wavelength indicating the maximum value of cos Δ in a predetermined wavelength region in the spectrum of cos Δ when the injection amount is changed while the injection energy is kept constant, and the injection amount are defined in advance as a second correlation. The method further comprises a step of preparing, and in the fourth step, the spectrum of the cos Δ obtained in the second step is compared with the second correlation to obtain a spectrum of ions injected into the semiconductor layer. After obtaining the implantation amount, this ion implantation amount
This is a method of measuring the thickness of the amorphous region in the semiconductor layer by comparing the above correlation.

When the wavelength of the measurement light detected as elliptically polarized light is changed by these methods, a parameter relating to the complex refractive index of the semiconductor layer, such as cos Δ, is obtained. And
A spectrum such as cos Δ is obtained as information relating to the thickness and film quality of the region into which the impurity ions have been implanted, and the thickness of the semiconductor layer into which the ion implantation has been performed can be examined nondestructively. In particular, by preparing the first correlation and the second correlation in advance, and comparing the cos Δ spectrum obtained as a result of the measurement by the spectroscopic ellipsometry method with these correlations, the thickness of the amorphous region can be obtained. Can be measured nondestructively with high reproducibility, and the thickness of the amorphous region can be detected simply and quickly.

By performing the first to fourth steps on a region of the semiconductor layer into which a plurality of impurity ions have been implanted, the distribution of the thickness of the amorphous region in the semiconductor layer can be measured.

The fifth method for evaluating a semiconductor device of the present invention includes the same basic first to fourth steps as those of the first method, and further includes the steps of: Step 4 is performed to determine a first thickness of the amorphous region. After the semiconductor layer is subjected to the heat holding process, the semiconductor layer is subjected to the first to fourth steps to form the amorphous region. Determining the second thickness of the amorphous region, and measuring the temperature of the heat holding process from the recovery rate calculated from the first thickness and the second thickness of the amorphous region and the time of the heat holding process. Can be prepared.

According to this method, unlike the method using a wafer with a temperature sensor, the temperature on the upper surface side of the substrate can be detected, and the measurement can be performed with almost no limitation on the temperature range.

In the method for evaluating a semiconductor layer, the method further includes a step of obtaining a correlation between a temperature of the heat holding process in the heat holding process and a decrease in the thickness of the amorphous region. Thus, the temperature of the heat holding treatment can be measured.

 This method allows for quick evaluation.

In the method for evaluating a semiconductor layer, the heat retention processing temperature is measured for a plurality of amorphous regions in the substrate, and a temperature distribution in the substrate or the processing apparatus is measured from the heat retention temperatures in the plurality of amorphous regions. be able to.

Since more detailed information can be obtained by this method, the evaluation result can be used for fine adjustment of conditions in various heat treatments.

A first method of manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device in a semiconductor layer of a substrate, wherein impurity ions are implanted into the semiconductor layer to form an amorphous region having disordered crystallinity. A first step, a second step of performing a process involving maintaining the amorphous region at a predetermined temperature, and a p-direction (a plane perpendicular to the optical axis and a plane perpendicular to the optical axis) in the semiconductor layer. Direction of the line of intersection with the plane containing light and reflected light) and s direction (in the plane perpendicular to the optical axis)
Linearly polarized measurement light that is inclined with respect to the surface of the semiconductor layer from a direction inclined with respect to a direction perpendicular to the surface of the semiconductor layer, and is reflected as elliptically polarized light from the semiconductor layer. A third phase of measuring at least cos Δ spectrum before and after the processing in the second step, where Δ is a phase difference between the p component and the s component of the reflected light; A fourth step of measuring a change in the thickness of the amorphous region before and after the processing in the second step based on a change in the spectrum of Δ, and a change in the thickness of the amorphous region before and after the processing; A fifth step of measuring the temperature of the heat holding process from a recovery rate calculated from the time of the heat holding process.

In the first method for manufacturing a semiconductor device, the method may further include determining a correlation between a temperature of the heat holding process in the heat holding process and a decrease in the thickness of the amorphous region. The temperature of the heat holding process can be measured based on the relationship.

As described below, an invention relating to a recording medium for causing a computer to automatically perform the procedure relating to the above-described semiconductor layer evaluation method can also be obtained.

According to a first recording medium of the present invention, a semiconductor layer having an amorphous region in which crystallinity is disordered by implanting impurity ions in a substrate is subjected to a process of maintaining the semiconductor layer at a predetermined temperature higher than room temperature. In the plane perpendicular to the optical axis (the direction of the line of intersection between the plane perpendicular to the optical axis and the plane containing incident light and reflected light) and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). Measuring light of linearly polarized light inclined to the surface of the semiconductor layer from a direction inclined to a direction perpendicular to the surface of the semiconductor layer,
When the phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer is Δ, at least co with the change in the wavelength of the measurement light
a recording medium used to evaluate the physical quantity of the semiconductor layer from the spectrum of sΔ, wherein a first procedure for storing a correlation between the thickness of the amorphous region and the spectrum of at least cosΔ; A second procedure of inputting a spectrum of at least cos Δ, which is a measurement result by spectroscopic ellipsometry of the amorphous region formed under the injection condition, and extracting a correlation to obtain at least cos Δ obtained in the second step. By comparing the spectrum of the above with the correlation, a program for causing a computer to execute a third procedure for measuring the thickness of the amorphous region in the semiconductor layer is recorded. In the first procedure, a specific ion implantation is performed. The relationship between the implantation energy in the dose and the thickness of the amorphous region is defined as the first correlation for each ion implantation dose. Then, the relationship between the spectrum of cos Δ and the implantation energy at a specific ion implantation amount is stored as a second correlation, and in the third procedure, the spectrum of cos Δ input in the second procedure is stored. To the second correlation to determine the implantation energy of the ions implanted into the semiconductor layer, and then compare the implantation energy to the first correlation to obtain the amorphous energy in the semiconductor layer. The thickness of the area can be measured.

In the first procedure, the relationship between the ion implantation amount at a specific implantation energy and the thickness of the amorphous region is defined as a first correlation for each implantation energy, and the spectrum of cos Δ at a specific implantation energy and the ion implantation amount are determined. Is stored as a second correlation,
In the third procedure, the cos input in the second procedure is
The amount of ions implanted into the semiconductor layer is determined by comparing the spectrum of Δ with the second correlation, and then the amount of ions implanted into the semiconductor layer is compared with the first correlation to obtain the semiconductor. The thickness of the amorphous region in the layer can be measured.

According to the second recording medium of the present invention, a semiconductor layer having an amorphous region with disordered crystallinity in which impurity ions are implanted in a substrate is subjected to a heat treatment, and the semiconductor layer is subjected to a p-direction (light direction) in a plane perpendicular to the optical axis. Measurement of linearly polarized light inclined with respect to the direction perpendicular to the axis and the direction of the intersection of the plane containing incident light and reflected light) and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). The light is incident on the semiconductor layer from a direction inclined with respect to a direction perpendicular to the surface thereof, and the phase difference between the p component and the s component of the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. When Δ is, a recording medium used to measure the temperature of the heat treatment from the spectrum of at least cos Δ with a change in the wavelength of the measurement light, the time of the heat treatment at a specific temperature and Relationship with the decrease in thickness of the amorphous region The thereby stored as correlation 1
A second procedure for storing the thickness of the amorphous region before the heat treatment, a third procedure for storing the thickness of the amorphous region after the heat treatment, and a thickness of the amorphous region before and after the heat treatment. And the correlation are taken out, and the amount of reduction in the thickness of the amorphous region before and after the heat treatment is compared with the correlation to obtain the heat treatment temperature. is there.

According to the third recording medium of the present invention, a semiconductor layer having an amorphous region in which crystallinity is disordered by implanting impurity ions in a substrate is subjected to heat treatment, and the semiconductor layer is subjected to a p-direction (light direction) in a plane perpendicular to the optical axis. Measurement of linearly polarized light inclined with respect to the direction perpendicular to the axis and the direction of the intersection of the plane containing incident light and reflected light) and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). The light is incident on the semiconductor layer from a direction inclined with respect to a direction perpendicular to the surface thereof, and the phase difference between the p component and the s component of the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. When Δ is, a recording medium used to measure the temperature of the heat treatment from the spectrum of at least cos Δ with a change in the wavelength of the measurement light, the time of the heat treatment at a specific temperature and Relationship with the decrease in thickness of the amorphous region A first procedure for storing et obtained recovery rates as a correlation for each temperature, a second for storing the thickness before the heat treatment of the amorphous region
And a third procedure for storing the thickness of the amorphous region after the heat treatment and the heat treatment time, and extracting the correlation between the amount of decrease in the thickness of the amorphous region before and after the heat treatment and the correlation to obtain the heat treatment of the amorphous region. A program for causing a computer to execute the fourth procedure for obtaining the heat treatment temperature by comparing the recovery rate obtained by dividing the amount of decrease in thickness before and after by the heat treatment time with the above correlation is recorded.

According to the fourth recording medium of the present invention, a semiconductor layer having an amorphous region with disordered crystallinity in which impurity ions are implanted in a substrate is subjected to a heat treatment, and the semiconductor layer is subjected to a p-direction (light) in a plane perpendicular to the optical axis. Measurement of linearly polarized light inclined with respect to the direction perpendicular to the axis and the direction of the intersection of the plane containing incident light and reflected light) and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). The light is incident on the semiconductor layer from a direction inclined with respect to a direction perpendicular to the surface thereof, and the phase difference between the p component and the s component of the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. Is a recording medium used to measure the temperature of the heat treatment from at least the spectrum of cos Δ with the change in the wavelength of the measurement light, and the temperature of the heat treatment under a specific time. Relationship with the decrease in thickness of the amorphous region A first procedure for storing the recovery rate determined as a correlation, a second procedure for storing the thickness of the amorphous region before heat treatment, and a third procedure for storing the thickness of the amorphous region after heat treatment and the heat treatment time. And the correlation between the amount of reduction in the thickness of the amorphous region before and after the heat treatment and the correlation are taken out, and the correlation between the recovery rate obtained by dividing the amount of decrease in the thickness of the amorphous region before and after the heat treatment by the heat treatment time. And a program for causing a computer to execute the above-described procedure for determining the heat treatment temperature.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a structure of a part of a semiconductor wafer used for evaluation in an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a configuration of an evaluation device used for evaluation in the embodiment of the present invention.

FIGS. 3A and 3B are data obtained by experiments performed in the embodiment of the present invention, and are diagrams respectively showing the spectra of tan Ψ and cos Δ in the low-concentration amorphous region.

FIGS. 4A and 4B are data obtained by experiments performed in the embodiment of the present invention, and are diagrams respectively showing the spectra of tan Ψ and cos Δ in the high-concentration amorphous region.

FIG. 5 is a diagram showing data of an experiment performed in the embodiment of the invention, showing a spectrum of cos Δ in an amorphous region when high-concentration ion implantation is performed by changing the implantation energy.

FIG. 6 is a view showing data from an experiment conducted in the embodiment of the present invention, showing a spectrum of tan に お け る in an amorphous region when high-concentration ion implantation is performed by changing the implantation energy.

FIG. 7 shows data of the first specific example, in which TEM, TRIM,
FIG. 4 is a diagram comparing the relationship between the ion implantation energy obtained by measurement by spectroscopic ellipsometry and the thickness of an amorphous region.

FIG. 8 is data of the first specific example of the first embodiment, and is a diagram showing the relationship between the ion implantation amount obtained by measurement by spectroscopic ellipsometry and the thickness of the amorphous region.

FIGS. 9A to 9C show data of the second specific example of the first embodiment. The uniformity of the thickness of the amorphous region in the wafer obtained by the measurement by the spectroscopic ellipsometry is determined by the thermal wave method. FIG. 7 is a diagram comparing with data on uniformity in a wafer by a sheet resistance method.

FIG. 10 shows comparison data in the third specific example of the first embodiment, which is a spectrum of cos Δ, tan に お け る in a silicon single crystal region where ion implantation is not performed.

FIG. 11 shows data in the third specific example of the first embodiment, which is 1 × 10 ¹⁴ cm using the ion implantation apparatus of Company A.
^In the amorphous region after ion implantation of ^-2
Δ, tan Ψ spectrum.

FIG. 12 shows data in the third specific example of the first embodiment, and is 5 × 10 ¹³ cm using the ion implantation apparatus of Company A.
^In the amorphous region after ion implantation of ^-2
Δ, tan Ψ spectrum.

FIG. 13 shows data in the third specific example of the first embodiment, and is 5 × 10 ¹³ cm using an ion implantation apparatus of Company B.
^In the amorphous region after ion implantation of ^-2
Δ, tan Ψ spectrum.

FIG. 14 shows data in the third specific example of the first embodiment, and is 1 × 10 ¹⁴ cm using an ion implantation apparatus of Company B.
⁴ is a spectrum of cos Δ, tan に お け る in an amorphous region where ion implantation of ⁻² was performed at a current density of 615 μA.

FIG. 15 shows data in the third specific example of the first embodiment, which is 1 × 10 ¹⁴ cm using an ion implantation apparatus of Company B.
⁴ is a spectrum of cos Δ, tan に お け る in an amorphous region in which ⁻² ion implantation is performed at a current density of 2000 μA.

FIG. 16 shows data in the first specific example of the second embodiment.
FIG. 4 is a diagram illustrating a relationship between a wafer holding temperature and a thickness of an amorphous region.

FIG. 17 shows data in the second specific example of the second embodiment.
FIG. 4 is a diagram illustrating a relationship between a wafer holding temperature and a film quality of a region (amorphous region) into which impurity ions are implanted.

FIG. 18A shows data in the third specific example of the second embodiment, and is a diagram showing a change in the thickness of the amorphous region with respect to the annealing time obtained for various samples. FIG. 18 (b) is a table created from the data of FIG. 18 (a).

FIG. 19 is a diagram showing the relationship between the progress rate of recovery (recrystallization) of an amorphous region and annealing conditions described in the literature.

FIG. 20A is data in the fourth specific example of the second embodiment, and is data showing the temperature dependence of the amount of decrease in the thickness of the amorphous region when flash annealing is performed. FIG. 20 (b) is a diagram showing the change over time in the thickness of the amorphous region when normal annealing is performed under the condition at point D20 in FIG. 20 (a).

FIG. 21 is a diagram showing data in the fifth specific example of the second embodiment, showing the distribution of the thickness of the amorphous region in the wafer in the state indicated by the point A16 in FIG.

FIG. 22 is a diagram showing data in the fifth specific example of the second embodiment, showing the distribution of the thickness of the amorphous region in the wafer in the state shown at point C16 in FIG.

FIG. 23 shows data in the fifth specific example of the second embodiment, and shows the temperature distribution in the wafer obtained by subtracting the thickness of each measurement point shown in FIG. 21 from the thickness of each measurement point shown in FIG. FIG.

FIG. 24 is a diagram showing data in the sixth specific example of the second embodiment, showing the distribution of the absorption coefficient of the amorphous region in the wafer in the state shown at point A16 in FIG.

FIG. 25 is a diagram showing data in the sixth specific example of the second embodiment, showing the distribution of the absorption coefficient of the amorphous region in the wafer in the state shown at point C16 in FIG.

FIGS. 26 (a) and 26 (b) are flowcharts in the first specific example of the third embodiment, showing a procedure for determining whether or not an ion-implanted amorphous region is acceptable and a procedure for changing ion implantation conditions, respectively. It is a flowchart.

FIG. 27 is a flowchart showing a procedure for measuring the temperature of the wafer surface during annealing in the second embodiment.

FIG. 28 is a flowchart showing a procedure for measuring the temperature of the wafer surface from the recovery rate during annealing at a constant temperature in the second embodiment.

FIG. 29 is a flowchart showing a procedure for measuring the temperature of the wafer surface from the recovery rate during annealing for a fixed time in the second embodiment.

FIGS. 30A and 30B are tables respectively showing a first correlation and a second correlation in the first specific example of the first embodiment.

FIG. 31 shows a method of obtaining the thickness of the amorphous region using the first and second correlations when the amount of ion implantation in the first specific example of the first embodiment is known.

FIG. 32 shows a case where the implantation energy in the ion implantation in the first specific example of the first embodiment is known.
1. This is a method of obtaining the thickness of the amorphous region using the second correlation.

FIG. 33 is a chart summarizing the contents of each specific example of each embodiment as a list.

Best Embodiment FIG. 33 is a table summarizing the contents of each specific example of each embodiment described below.

First, a semiconductor evaluation method according to each embodiment that supports the basic principle of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a structure in an ion implantation step of a semiconductor device (n-channel MOS transistor) to be evaluated according to an embodiment of the present invention. As shown in the figure, in a MOS transistor manufacturing process performed in a wafer state, a hydrogen separation 12 made of a LOCOS film is formed on a silicon substrate 11 (silicon wafer), and an active region surrounded by the element separation 12 is formed. A gate insulating film 13 and a gate electrode 14 are formed therein. And in the ion implantation process,
Impurity ions such as As + ions are implanted into the silicon substrate 11 to form a high-concentration source
A drain region 15 is formed. And the silicon substrate 11
In the other region, a monitor region 16 for measuring the suitability of the ion implantation conditions of the high concentration impurity is formed,
As + ions are implanted into the monitor region 16 simultaneously with the source / drain regions 15. When forming the source / drain regions of the p-channel MOS transistor,
B + is implanted into another monitor area to measure boron ion implantation conditions.

FIG. 2 shows the condition of ion implantation into the source / drain region 15 of the n-channel MOS transistor in the monitor region.
FIG. 2 is a side view schematically showing a configuration of a spectroscopic ellipsometer for performing measurement by using 16; Output from Xe light source 20
The Xe light is converted into linearly polarized light by the polarizer 21 and is incident on the silicon substrate 11 (monitor area 16) at an angle θ0 with respect to the direction perpendicular to the substrate surface, and the light reflected as elliptically polarized light passes through the analyzer 22. While being incident on the post-spectrometer 23 and splitting, the complex refractive index N = n− at each wavelength is detected by the detector 24.
It is configured to measure ik. However, the axes of the linearly polarized light of the incident light are the p direction (the direction of the intersection line between the plane perpendicular to the optical axis and the plane including the incident light and the reflected light) and the s direction (p in the plane perpendicular to the optical axis). Direction perpendicular to the direction).

Next, the measurement principle of the spectroscopic ellipsometry used in the present embodiment will be described. Silicon substrate shown in FIG. 2 above
Assuming that the angle between the incident light of Xe light on 11 and the normal of the silicon substrate is θ0, the complex refractive index N = n of the sample at each wavelength
−ik is represented by the following equations (1) and (2).

n ² −k ² = sin ² θ ₀ [1+ ｛tan ² θ ₀ (cos ² 2Ψ−sin ² Ψsin ² Δ)} / (1 + sin ² ΨcosΔ) ² ] (1) 2nk = (sin ² θ ₀ tan ² θ ₀ sin ⁴ Ψsin Δ ) / (1 + sin2ΨcosΔ) ² (2) where Ψ indicates the amplitude reflectance ratio between the p component and the s component, and Δ indicates the phase difference between the p component and the s component. That is, by measuring the tan Ψ, cos Δ of the reflected light, the complex refractive index N representing the physical properties of the sample at each wavelength is obtained from the equations (1) and (2).

Here, the present inventors can obtain important information regarding ion implantation conditions by measuring the spectrum by spectroscopically measuring the tan Ψ, cos Δ of the reflected light without obtaining the complex refractive index N itself of the sample. It was found out that it was obtained by the following process.

In obtaining the data shown in the following figures, a p-type silicon substrate doped with a p-type impurity in advance was used as the silicon substrate, the resistivity was 10.0 to 15.0 (Ω · cm), and the crystal orientation of the substrate surface was (100 ). As an ion implantation species, As
Using +, the implantation energy is varied between 20 and 80 (keV) and the implantation volume is varied between 2 and 4 × 10 ¹⁵ cm ⁻² . The spectroscopy is performed in the range of 250 to 800 nm.

FIGS. 3A and 3B show tan tan and cos Δ spectra of reflected light from a silicon substrate not subjected to ion implantation, respectively (in FIG. 3B, spectrum line 3A). On the other hand, FIGS. 4A and 4B show ta of reflected light from the silicon substrate after high-concentration impurity ion implantation.
The spectra of nΨ and cos Δ are shown, respectively. FIG.
(B) wavelength 45 at the valley position of the cos Δ spectral line
As can be seen by comparing 0 nm with the wavelength 400 nm at the valley position of the spectrum line 3A of the cos Δ in FIG. 3b, when the impurity is doped into the silicon single crystal, the spectrum shape of the cos Δ becomes
The valley position tends to move to the negative side in the long wavelength region (450 nm to 850 nm) compared to the spectrum line 3A when no injection is performed. Therefore, it is clear that the spectrum of tan Ψ, cos Δ has been changed by ion implantation.

Then, as shown in FIG. 3B, generally, when an impurity is doped into a silicon single crystal, the spectral shape of cos Δ becomes larger as the dose increases with respect to the spectral line 3A when not implanted. Shows a tendency to move to the negative side (spectral lines 3B, 3C). Therefore, for a single crystal silicon substrate, t at a certain wavelength (for example, 630 nm)
By measuring an Ψ and cos Δ, it is possible to grasp conditions such as a dose amount in ion implantation to some extent.

On the other hand, FIG. 5 shows the change in the spectrum shape of cos Δ when the implantation energy is changed for the amorphous silicon layer, and FIG. 6 shows the change in the spectrum shape of tan と き when the implantation energy is changed for the amorphous silicon layer. Are respectively shown. The dose of impurity ions (As +) is 4 × 10
¹⁵ cm ^-2 .

As can be seen from FIGS. 5 and 6, in the case of ion implantation into the amorphous silicon layer, a certain wavelength (for example, 630 nm) is used.
Even if cos Δ, tan Ψ in m) is measured and the implantation energy increases, the measured value of cos Δ, tan 変 化 does not have a regular change, so the ion implantation energy cannot be grasped from the measurement result.

As described above, conventionally, it has not been possible to evaluate the suitability of conditions such as ion implantation energy for an impurity diffusion region formed by ion implantation of high-concentration impurities by ellipsometry.

First Embodiment Hereinafter, specific examples which are examples of information obtained by using the spectroscopic ellipsometry will be described.

-First Specific Example- In this specific example, cos Δ by spectroscopic ellipsometry is used.
A method of measuring the thickness of the amorphous region by comparing the spectrum of (or tan Ψ) with the correlation will be described.
In the present specification and the description of the claims, the “spectrum” may be grasped as a spectrum pattern, or may be grasped as a numerical value (table) of wavelength vs. cos Δ (or tan Ψ). It may be.

When obtaining the data shown in FIGS. 7 and 8 below, a p-type silicon substrate doped with a p-type impurity in advance is used, the resistivity is 10.0 to 15.0 (Ω · cm), and the crystal on the substrate surface is used. The bearing is (100). As + is used as an ion implantation species, the implantation energy is changed between 20 and 80 (keV), and the implantation amount is changed between 2 and 4 × 10 ¹⁵ cm ⁻² .
The spectroscopy is performed in the range of 250 to 800 nm.

FIG. 7 is data showing the dependence of the thickness of the amorphous region on the implantation energy when the implantation amount is fixed at 4 × 10 ¹⁵ cm ⁻² . In the figure, the horizontal axis represents the implantation energy (ke
V), and the vertical axis indicates the thickness (nm) of the amorphous region. The data in FIG. 7 is obtained by measuring the thickness of the amorphous region by TEM under the implantation energy conditions (20, 30, 40, 50 (keV)) shown in FIGS.
It was obtained by examining the correlation between the spectrum shape of Ψ and the measurement result of the thickness of the amorphous region. FIG. 7 also shows the relationship between the implantation energy by TEM and the thickness of the amorphous region. As can be seen from FIG. 7, the thickness of the amorphous region obtained by the spectroscopic ellipsometry according to the present embodiment is close to the result of actual measurement by TEM, and non-destructive and highly accurate measurement can be performed. That is, it is possible to provide an evaluation method suitable for an in-line inspection (referring to an inspection between processes as shown in FIG. 2).

FIG. 8 is data showing the dependence of the thickness of the amorphous region on the implantation amount when the ion implantation energy is fixed at 40 (keV). In the figure, the horizontal axis represents the injection amount (× 10 ¹⁵
cm ⁻² ), and the vertical axis indicates the thickness (nm) of the amorphous region. The data in FIG. 8 shows that the injection amount (dose amount) is 2.0,
The thickness was measured by TEM when the thickness was changed in five steps of 2.5, 3.0, 3.5, 4.0 × 10 ¹⁵ cm ^-2 , and the spectrum shape of cos Δ, tan と at that time was compared with the measurement result of the thickness of the amorphous region. This is obtained by checking the correlation in advance.

FIG. 30A shows the thickness d11, d12, d13,... Of the amorphous region when the implantation energy E is changed to various values E1, E2, E3,. , D2, D3,
... is a matrix that summarizes what was determined for each. The relationship between the implantation energy E and the thickness d of the amorphous region when the amount of ion implantation shown in the matrix is constant is defined as a first correlation. This may be summarized as the implantation energy dependence of the film thickness of the amorphous region as shown in FIG.

Alternatively, the thickness d11, d21, d31,... Of the amorphous region when the implantation amount is changed to various values D1, D2, D3,.
It may be interpreted as what was determined for each of the three. In that case, the relationship between the implantation amount D and the thickness d of the amorphous region when the implantation energy of the ion implantation shown in the matrix is constant is the first correlation. This may be summarized as the dependency of the film thickness of the amorphous region on the injection amount as shown in FIG.

FIG. 30 (b) shows a spectrum pattern of cos Δ (or a relational table of measured wavelengths vs. numerical values of cos Δ) when the injection energy E is changed to various values E1, E2, E3,. ) Is a matrix in which the values determined for each of the injection amounts D1, D2, D3,... The relationship between the injection energy E and the spectrum of cos Δ shown in this matrix is defined as a second correlation.

Alternatively, it is interpreted that the spectrum of cos Δ when the injection amount is changed to various values D1, D2, D3,... While the injection energy E is constant is obtained for each injection energy E1, E2, E3,. May be. In this case, the relationship between the injection energy and the cos Δ spectrum when the injection amount D shown in the matrix is constant is the second correlation.

In this specific example, FIG. 5, FIG. 7, FIG.
By using the data of (a) and (b), the thickness of the amorphous region can be known by the following method.

The first method is the simplest method, and relates to the spectral pattern of cos Δ (or tan Ψ) obtained by performing a spectroscopic ellipsometry measurement on a certain amorphous region (or the relationship between the numerical values of the measurement wavelength cos Δ). Table)
The wavelength vs. cos Δ (or the wavelength under each injection condition in FIG.
tan Ψ) (second correlation),
In this method, the best matching is selected to determine the thickness of the amorphous region. This may be a spectrum shape, or a table in which numerical values of the wavelength value and the cos Δ value correspond to each other. This is because once the implanted ions are determined, the specific cos Δ
This focuses on the point that a spectrum shape of (or tan Ψ) is obtained. When the spectrum shape is used, for example, a fingerprint collation system can be applied.

The second method is a method shown in FIG. 31 in which the thickness of the amorphous region is obtained by utilizing the first and second correlations when the implantation amount in ion implantation is known.

First, in step ST61, the thickness d of the amorphous region when the implantation energy E is changed to various values E1, E2, E3,...
.., And this is stored as a first correlation shown in FIG. 30 (a).

Next, in step ST62, a relationship between the spectrum of cos Δ obtained from the amorphous region formed with a constant implantation amount and the implantation energy E is created as a second correlation,
This is stored as the second correlation shown in FIG.

Next, in step ST63, a spectrum pattern of cos Δ is obtained by performing a measurement by a spectroscopic ellipsometry method on an amorphous region formed with a known injection amount. This may be a table in which the numerical values of the wavelength value and the cos Δ value correspond to each other. For example, assume that the spectrum pattern SA5 shown in FIG. 5 is obtained at this time.

Next, in step ST64, the injection energy E can be determined by comparing the spectrum pattern SA5 with the second correlation. For example, in the example shown in FIG.
It is assumed that the implantation energy E giving 5 A is 35 keV.

Next, in step ST65, the thickness d of the amorphous region is obtained by comparing the obtained implantation energy E with the first correlation. For example, when the implantation energy E is found to be 35 keV, the thickness of the amorphous region can be determined to be 62 nm with reference to the table of FIG. 30B or FIG. In general, the thickness of the amorphous region may be determined in steps of about 5 nm in many cases. Therefore, the thickness of the amorphous region may be approximately 60 nm. Actually, as shown in FIG. 7, if fitting is performed so that the film thickness is calculated from the measured data of the ellipsometry, this method can also be used in the apparatus from the measured data similarly to the first method. , The thickness of the amorphous region is instantaneously calculated. It is clear that the calculation results almost match the measured values by TEM.

The third method is the method shown in FIG. 32, in which the first and second
Is a method of obtaining the thickness of the amorphous region by utilizing the correlation.

First, in step ST71, the thickness d of the amorphous region when the implantation energy is changed to various values D1, D2, D3,... , And this is stored as a first correlation.

Next, in step ST72, the relationship between the cos Δ spectrum obtained from the amorphous region formed at a constant implantation energy and the implantation amount is created as a second correlation, and FIG.
This is stored as the second correlation shown in FIG.

Next, in step ST73, a spectral pattern of cos Δ is obtained by performing measurement by a spectroscopic ellipsometry method on an amorphous region formed with a known implantation energy. This may be a table in which the numerical values of the wavelength value and the cos Δ value correspond to each other.

Next, in step ST74, the injection amount D can be determined by comparing the spectrum pattern of cos Δ with the second correlation.

Next, in step ST75, the obtained implantation amount D is compared with the first correlation to determine the thickness d of the amorphous region. That is, the thickness of the amorphous region can be determined with reference to the table of FIG. 30B or FIG. Actually, as shown in FIG. 8, if fitting is performed so that the film thickness is calculated from the actual measurement data of ellipsometry,
According to this method as well, the thickness of the amorphous region is instantaneously calculated from the measurement data by calculation in the apparatus as in the first method.

The fourth method is a method in which the dependence of the thickness of the amorphous region on the implantation energy shown in FIG. 7 is combined with the relationship between the implantation energy and the spectrum shape shown in FIG.
In a predetermined wavelength region of the cos Δ spectrum of the reflected light, the thickness of the amorphous region can be almost estimated if the wavelength showing the maximum value of the spectrum is known. If the first correlation is set in the same manner as in the second method, and the relationship between the wavelength showing the maximum value and the implantation energy E is stored as the second correlation for each ion implantation amount, FIG. It is also possible to easily obtain the thickness of the amorphous region by the same procedure as the flowchart shown in FIG.

The fifth method is a method in which the dependency of the thickness of the amorphous region on the implantation amount shown in FIG. 8 is combined with the relationship between the implantation amount and the spectral pattern shown in FIG. 3B. Reflected light co
In a predetermined wavelength region of the spectrum of sΔ, if the maximum value of cosΔ in the spectrum is known, the thickness of the amorphous region can be almost estimated. If the first correlation is set in the same manner as in the third method, and the relationship between the maximum value of cos Δ and the injection amount is stored as the second correlation for each ion energy, FIG. It is also possible to easily obtain the thickness of the amorphous region by the same procedure as that shown in the flowchart.

Second specific example (in-plane distribution of thickness of amorphous region) FIGS. 9 (a), 9 (b) and 9 (c) show measurements on the same wafer by spectroscopic ellipsometry, thermal wave method and sheet resistance method. FIG. 4 is a diagram showing the in-wafer uniformity of an amorphous region obtained by the above method. As + injection energy 40
(KeV)), and shows the measurement results when implanting under the conditions of a dose of 5 × 10 ¹⁵ cm ⁻² . In the spectroscopic ellipsometry according to the present embodiment shown in FIG. 3A, the thickness of the amorphous region is 69 nm and the in-plane uniformity is 0.153%. In FIG. 7A, the portion where the thickness is reduced as indicated by (-) is the region where the thickness is amorphized. FIG. 3B shows the in-plane uniformity of the ion implantation amount by the thermal wave method, and a square portion indicates a region of an average value. FIG. 3C is a diagram showing the in-plane uniformity of the ion implantation amount by the sheet resistance method. The contour lines in each figure indicate boundaries where a difference of 0.5% occurs. Here, the thermal wave value is a relative amount, and it is not always known whether or not it accurately reflects the ion implantation amount. According to the data shown in FIG. 9C, the in-plane uniformity of the ion implantation amount is very poor. When using the resistance method, a heat treatment for activating the implanted impurities is necessary to measure the sheet resistance,
It is considered that the in-plane uniformity was deteriorated by this heat treatment.

On the other hand, according to the in-plane uniformity measurement of the thickness of the amorphous region by the spectroscopic ellipsometry method according to the present embodiment, the non-destructive variation in the thickness of the amorphous region in the wafer surface is mixed with factors of the heat treatment. Instead, it can be grasped as a variation due to only the injection condition.

-Third Specific Example- This specific example relates to information obtained from a characteristic shape of the spectral method of tan Ψ, cos Δ measured by the spectroscopic ellipsometry method of the present invention.

FIG. 10 shows the spectral lines of tan Ψ and cos Δ by the spectroscopic ellipsometry method for the silicon substrate into which the impurity ions were not implanted, and FIGS. 11 to 15 show that the impurity ions were implanted into the silicon substrate under the conditions shown in each figure. The spectral lines of tan Ψ and cos Δ by spectroscopic ellipsometry for the region are shown, respectively.

Here, there are three characteristic regions Ra, Rb, and Rc in the spectrum line of cos Δ with respect to the silicon substrate into which the impurity is not implanted as shown in FIG. Ra is a decreasing region where the spectral line changes to the lower right. Rb is a minimal region having a certain width where the value of cos Δ is minimal. Rc is an increase region where the spectral line changes to the right. Also, the decreasing area Ra
Is characterized by the presence of a hump portion Rh. Then, the shape of this characteristic region in each of the above figures and the cos by the spectroscopic ellipsometry method after the ion implantation is performed.
By comparing the shape of the spectral line of Δ, tan Ψ,
The following information is obtained:

(1) Difference in spectral line shape due to difference in dose amount The relationship between the difference in injection amount and the difference in cos spectrum shape when using the same implanter will be discussed. Figures 11 and 12
, The reduced region in the spectrum of cos Δ
The gradient at Ra is gentler in FIG. 11, and the hump portion Rh to appear in the decreasing region Ra is less clear in FIG. As shown in FIG. 10, the hump portion Rh clearly appears in the cos Δ spectrum line of the substrate not implanted, whereas the hump portion Rh does not clearly appear in FIG. From this, it is understood that the condition of FIG. 11, that is, the condition where the amount of implanted impurity ions is large is a condition under which the silicon substrate is likely to be made amorphous. Also, comparing FIG. 13 with FIG. 14, the gradient of the reduction region Ra is gentle and the hump portion Rh is unclear in FIG. 14, which is a condition of a large amount of ion implantation, and the same conclusion as above is obtained. can get.

(2) Comparison of Injector Performance When comparing FIG. 12 with FIG. 13, the hump portion Rh in the reduced region Ra of the spectrum in FIG.
Thirteen has a gentler gradient of the increase region Rc. As shown in FIG. 10, it can be seen that the hump portion Rh clearly appears in the cos Δ spectrum line of the substrate not implanted, and the gradient of the increase region Rc is steep. The ion implantation conditions shown in FIG. 12 and FIG. 13 are the same except that the implantation apparatus is different. Thus, it can be seen that the ion implantation apparatus of Company B makes the silicon substrate easier to amorphize. In other words, the performance of the ion implantation apparatus can be evaluated by the method of the present embodiment.

(3) Current Density Dependence When comparing FIG. 14 and FIG. 15, the slope of the decreasing region Ra and the increasing region Rc is slightly gentler in the spectrum of FIG. 14 than in the spectral line of FIG. This can be understood from, for example, the fact that the value of cos Δ at the same wavelength in FIG. 15 is smaller than the value of cos Δ at a wavelength of 300 nm in FIG. Therefore, it is understood that the condition shown in FIG. 15 makes it difficult to make the silicon substrate amorphous. Here, FIG.
15 is different from the condition shown in FIG. 15 only in that the condition shown in FIG. 15 is large in current density.
That is, when ion implantation is performed with a large current as shown in FIG. 15, it is understood that a so-called beam annealing effect occurs in which the ion implantation attempts to restore the amorphous region to a crystalline state.

Also, regarding this current density dependency, comparing FIG. 11 and FIG. 15, the hump portion Rh of FIG. 11 is clearer than the hump portion Rh of FIG. 15, although the spectra are obtained by the same ion implantation amount. And the gradient of the decreasing region Ra is slightly steeper in FIG. Further, the minimum region Rb in FIG. 11 is flat, and the thickness of the amorphous region is thin. This indicates that the ion implantation apparatus of Company A has a greater beam annealing effect than the implantation condition of the ion implantation apparatus of Company B with a current density of 2000 μA. However, the current density of the ion implantation apparatus of Company A is unknown.

(4) Others As can be seen from a comparison of FIGS. 10, 11, and 12, for example, it can be seen that the gentler the spectrum shape of tan が, the more the disorder of crystallinity (amorphization) is advanced. Therefore, in addition to the shape of the spectrum of cos Δ,
By considering the shape of the spectrum of n Ψ
More accurate judgment can be made than judgment of ion implantation conditions and physical quantity of the amorphous region only from the shape of the spectrum of Δ. However, since the cos Δ spectrum pattern has more characteristic portions and changes greatly depending on the ion implantation conditions, it is generally sufficient to observe only the cos Δ spectrum pattern.

In each of the above specific examples, an example was described in which As + ions were implanted as impurity ions. However, the present invention is not limited to such specific examples, and B + ions, Si + ions,
The present invention can also be applied to a semiconductor layer into which + ions or the like have been implanted. Further, as the semiconductor layer, not only a silicon layer but also a semiconductor layer made of another semiconductor material such as a semiconductor layer made of a compound semiconductor can be applied.

Second Embodiment Next, a second embodiment relating to the application of the spectroscopic ellipsometry method for measuring the actual temperature of the substrate surface during processing such as annealing will be described.

-First Specific Example (Method of Measuring Actual Temperature of Substrate Surface)-First, the relationship between the annealing treatment and the thickness of the amorphous region is determined.

FIG. 16 is data showing the relationship between the wafer holding temperature and the thickness of the amorphous region for a wafer into which As + ions have been implanted under the conditions of 30 keV and 3 × 10 ¹⁴ cm ⁻² . The horizontal axis is
It shows the power of the power supply of the degas chamber, which is 0% when off and 100% at maximum. The degas chamber is a chamber attached to a CVD apparatus or a sputtering apparatus, and heats and holds a wafer in a vacuum state in the degas chamber. As described above, the display of the power supply of the degas chamber is displayed at 0 to 100%, but the surface temperature of the substrate installed in the chamber is not accurately known. The vertical axis represents the thickness of the amorphous region after the sample is kept at a predetermined temperature.
A substrate having a semiconductor layer into which As + ions have been implanted is used, and a substrate is heated in a vacuum state in a chamber using a preheating degas chamber of a Ti sputtering apparatus. The thickness of the amorphous region is measured by the same method as described with reference to FIGS. By spectroscopic ellipsometry in the amorphous region, points A16,
The film thickness of the amorphous region under the conditions of B16 and C16 is measured. The retention time of the amorphous region in the degas chamber is set to 30 seconds, and a so-called TC wafer having a temperature sensor attached to the back surface of the wafer is used, and the temperature is also measured by this temperature sensor. However, depending on the TC wafer, only the back surface temperature of the wafer is known, not the surface temperature of the wafer. The point A16 in the figure is a state where the time held in the degas chamber is “0”, that is, as-impl
ant sample data, point B16 is the data when the power of the degas chamber was set to 40% of the rated power (the backside temperature, which is the measured value of the TC wafer, was 250 ° C), and point C16 was the power of the degas chamber. 60% of rating (backside temperature is 27
0C), and the point D16 is data when the power of the degas chamber is set at 70% of the rated power (the backside temperature is 350 ° C). In the case of annealing at such a low temperature, the thickness does not change much after 30 seconds, but the thickness decreases.

On the other hand, FIG. 19 shows the literature (Journal of Applied Physics V).
ol.48, No.10, October 1977, p.4237)
ig.4, which is a diagram illustrating a relationship between a progress speed of recovery (recrystallization) of an amorphous region and annealing conditions. In FIG. 19, the horizontal axis represents temperature, and the vertical axis represents the recovery progress rate from the amorphous region to the crystal. From this figure, it can be seen that the recovery rate at 500 ° C. of the amorphous region formed by implanting As ions, for example, is about 60 ° / min.
As shown in the figure, it is known that there is a clear correlation between the annealing temperature and the recovery. However, 450 ° C
Nothing is shown about the rate of recovery at the following temperatures.

Here, it has been considered that an amorphous region formed by implantation of As + ions of, for example, 1 × 10 ¹⁵ cm ⁻² does not recover (recrystallize) when the annealing temperature is about 450 ° C. or lower. In contrast, FIG.
According to the data shown in the figure, the thickness of the amorphous region is reduced even at a low temperature annealing at a temperature of about 250 to 350 ° C., and even at such a low temperature, some recovery (recrystallization) of the amorphous region occurs. I understand.

Conventionally, temperature measurement in a chamber has been performed by a temperature sensor attached to the back surface of a TC wafer. However, even with the use of a TC wafer, although the temperature on the back surface of the wafer is known, the temperature on the front surface of the wafer, that is, the actual temperature at which the amorphous region is subjected to the heat treatment, cannot be measured. In addition, there is a limit to the temperature measurement range, and it is said that the measurement accuracy deteriorates when the temperature is increased to some extent (500 to 600 ° C. or higher).

On the other hand, according to the method of this specific example, if the correlation between the holding time and the recovery rate used in the later specific example or the correlation between the holding time and the amount of reduction in thickness is used, the temperature of the wafer surface can be accurately determined. Can be measured. Therefore, even in an apparatus such as a degas chamber in which only the power source power is displayed in%, it is possible to accurately measure how much the surface temperature of the wafer is at a specific power. Although the surface temperature of the wafer is not known only from the experimental data, if the thickness before and after the heat treatment is known using the thickness measurement of the first embodiment described above, the correlation between the holding time and the recovery rate can be calculated. Alternatively, the temperature during the heat treatment can be measured from the correlation between the holding time and the amount of decrease in the thickness. For the specific method,
It will be described later.

In this specific example, the measurement of the temperature of the wafer surface set in the degas chamber has been described. However, similarly, in a CVD apparatus, a sputtering apparatus, and an annealing apparatus, it is also possible to accurately measure the temperature of the wafer surface. it can. Further, knowing the surface temperature of the wafer means knowing the temperature distribution in the wafer surface and the temperature distribution in the region where the wafer is installed in the chamber.

-Second Specific Example- Next, a description will be given of the results of an experiment on a second specific example performed to determine the relationship between the annealing treatment conditions and the film quality of a region (amorphous region) into which impurity ions have been implanted.

FIG. 17 is data showing the relationship between the wafer holding temperature and the absorption coefficient of light incident on the amorphous region. However, the holding time in the wafer or the degas chamber is the same as the condition for measuring the thickness shown in FIG. A point A17 in the figure is a state where the time held in the degas chamber is “0”, that is, data of an as-implant sample, and a point B17 is shown in FIG.
17 is the data when the power of the degas chamber is set at 40% of the rated power (backside temperature 250 ° C), and the point C17 is the data when the power of the degas chamber is set at 60% of the rated power (backside temperature 270 ° C). The point D17 is data when the power of the degas chamber is set at 70% of the rated power (the back surface temperature is 350 ° C.). However, the temperature in parentheses is TC
This is the temperature indicated by the temperature sensor attached to the wafer. After a lapse of 30 seconds, there is no significant change in the absorption coefficient, but a change is observed.

From the experimental results shown in FIG. 17, it was found that the difference in the film quality of the amorphous region due to the difference in the annealing conditions can also be evaluated. Although it takes a certain amount of time to observe the spectral shape of spectral ellipsometry, the film quality can be evaluated very quickly and easily only by determining the absorption coefficient. This absorption coefficient depends on the transparency of the amorphous region, and this value reflects the crystallographic state of the amorphous region. Therefore, for example, by determining in advance the range of the absorption coefficient that will not be defective in the manufacturing process and preparing it as an appropriate range, even in the actual manufacturing process, the absorption coefficient of the amorphous region may fall within the appropriate range. If the absorption coefficient does not fall within the appropriate range as a non-defective product, it is determined as a defective product, so that a pass / fail determination can be made very quickly.

-Third Specific Example- Next, a third specific example regarding the correlation between the change in the thickness and the absorption coefficient and the retention time in annealing obtained from the thickness measurement of the amorphous region using the spectroscopic ellipsometry will be described.

FIG. 18A is data showing changes in the thickness and the absorption coefficient with respect to the annealing time obtained for various samples. Here, ○ indicates the change in the thickness of the wafer implanted under the conditions of 30 keV and 4 × 10 ¹⁵ cm ^-2 , ● indicates the change in the absorption coefficient of the wafer implanted under the same conditions, and △ indicates the change in the absorption coefficient of the wafer implanted under the same conditions. The graph shows the change in the thickness of the wafer implanted under the conditions of 30 keV and 3 × 10 ¹⁴ cm ⁻² , and △ shows the change in the absorption coefficient of the wafer implanted under the same conditions. In each case, the temperature is maintained at 550 ° C. for a certain period of time.

The following can be understood from the inclination of the straight line connecting the data of ○ and △ shown in FIG.

Looking at the data of △, it is 10 seconds from the start of annealing
The change in thickness until the passage of time is (44.8-32) nm / 10 sec.
= 77 nm / min. This recovery (recrystallization) speed is much higher than the recovery speed at 550 ° C. of 20 nm / min shown in FIG. The recovery speed in 50 seconds after the lapse of 10 seconds from the start of annealing and after the lapse of 60 seconds is (32
−15) nm / 50 sec = 17 nm / 50 sec = 20.4 nm / min. This value is substantially equal to the rotation speed at 550 ° C. of 20 nm / min shown in FIG. In addition, 120 seconds from when 60 seconds elapse to 180 seconds elapse
The recovery speed between sec is 15 (nm) / 120 (sec) = 7.5n
m / min, very small. Then, the amorphous region has disappeared after 120 seconds.

Regarding the data of ○, the change in the recovery speed is almost equal to the data of ② described above. Furthermore, it should be noted that the amorphous region formed by ion implantation at a low concentration of 3 × 10 ¹⁴ cm ⁻² progresses as the annealing time elapses and eventually becomes almost “0”. The thickness of the amorphous region formed by ion implantation at a high concentration of 4 × 10 ¹⁵ cm ⁻² is almost constant after about 50 seconds. In other words, 50sec
After some time, little recovery has taken place. this is,
It seems to be related to the amount of residual oxygen.

Also, looking at the data of ● and ▲, it can be seen that the changes are relatively similar to the changes of ○ and △. This indicates that not only the change in the film quality but also the change in the thickness can be grasped to some extent by looking at the value of the absorption coefficient.

FIG. 18B is a table summarizing the elapsed time of annealing, the thickness of the amorphous region, and the recovery rate based on the data (annealing at 550 ° C.) of FIG. This table is for the data of △, but a similar table can be created for the data of ○. By preparing a table as shown in FIG. 18B for each of various annealing temperatures, the annealing temperature can be known from the recovery speed and the holding time.

As described above, according to the present specific example, it is possible to determine the time change of the recovery speed from amorphous to crystalline at a predetermined annealing temperature, and it is also possible to detect the annealing temperature.

-Fourth Specific Example- Next, the relationship with the change in thickness due to the recovery of the region (amorphous region) into which the impurity ions were implanted at the same annealing temperature as the data shown in FIG. A fourth specific example obtained for the following low-temperature annealing will be described.

FIG. 20 (a) shows the recovery rate of the amorphous region when the flash annealing is performed under the condition that the retention time is almost “0”, that is, the wafer is annealed under the condition that the power is turned off immediately after the temperature rise. Is the data showing the temperature dependence of. The data in FIG. 20 (a) shows that As +
This was obtained for a wafer implanted under the conditions of keV and 3 × 10 ¹⁴ cm ⁻² . As shown in the figure, the amount of reduction in thickness due to the recovery of the amorphous region changes almost linearly with the annealing temperature. FIG. 20
The recovery of the region (amorphous region) implanted with impurity ions formed under the condition shown in FIG. 7A has a remarkable tendency not to progress very much as the annealing temperature is lowered even if the annealing time is further increased. Was seen in

In FIG. 20A, points B20, C20, D20, E20, and F20 are annealed at 250 ° C., 270 ° C., 350 ° C., 450 ° C., and 550 ° C., respectively. The recovery thickness of the amorphous region is 0.4n each
m, 1.8 nm, 2.8 nm, 6.2 nm, and 9 nm. Point B20, C20, D20
At these three points, the annealing temperature is low, indicating a peculiar phenomenon when recovering from amorphous to crystalline.

FIG. 20B is a diagram showing a change with time of the amorphous film thickness in the normal annealing under the condition of the point D20. As shown in the figure, even if the film is held for a long time under the condition of the point D20, after the thickness is reduced by 2.8 nm in a very short time, no further crystallization proceeds, and the film thickness of the amorphous region is not increased. Remains constant. Similar phenomena are observed in normal annealing under the conditions of points B20 and C20. That is,
When the annealing temperature is low, the amorphous film thickness instantaneously changes, but thereafter crystallization does not proceed. If this phenomenon is utilized, for example, in an apparatus that performs processing at a temperature of 450 ° C. or less, which does not easily progress from amorphous to crystal, for example, As
The amorphous region formed by implanting + ions at 30 keV and 3 × 10 ¹⁴ cm ⁻² is held in the apparatus for a desired period of time to reduce the amount of decrease in the thickness of the amorphous region before and after the treatment. By calculating, the accurate annealing temperature can be obtained based on FIG.

The data as shown in FIG. 20 (a) is converted into an amorphous region (specifically, MOSFET
In the case of low-temperature annealing at 450 ° C. or less, the annealing temperature can be measured from the measurement result of the thickness of the amorphous region by the ellipsometry method. For example, if the change in the thickness of the amorphous region before and after annealing is about 6 nm under the condition of performing flash annealing, it can be seen that the annealing temperature is about 440 ° C.

That is, the actual annealing temperature can be determined by comparing the actual thickness change amount and the processing condition with such data using such a measurement result. Then, the annealing conditions can be accurately set from the data.

It is also possible to perform annealing while keeping the heating power constant, and to obtain a temperature-thickness correlation using the heating power as a parameter.

For annealing for a relatively short time at 450 ° C. or more, the annealing temperature is determined based on the recovery rate obtained from the amount of reduction in the thickness of the amorphous region measured by an ellipsometer and the annealing time using the data shown in FIG. Can be requested. However, the state of recovery of the amorphous region varies variously depending on the ion implantation conditions and the annealing temperature as shown in FIG. Therefore, the figure
Since the data shown in 19 may not always be suitable for accurate temperature measurement, the temperature dependence of the amount of reduction in the thickness of the amorphous region as shown in Fig. 20 must be determined in advance for each ion implantation condition. Is preferred. In particular, when the annealing time changes, it is preferable to previously obtain the change characteristic of the thickness of the amorphous region with respect to the elapse of the annealing time as shown in FIG.

Next, using the data shown in the first to fourth specific examples, the following temperature measurement can be performed.

FIG. 27 is a flowchart showing a procedure for measuring the temperature of the wafer surface during annealing using the data of FIG.

First, in step ST31, an amorphous region having a thickness of d0 is formed. Next, in step ST32, heat treatment (annealing) is performed under a certain temperature T for a certain time t, and the thickness d1 of the amorphous region at that time is measured.
Then, in a step ST33, the reduction amount d0-d1 of the thickness of the amorphous region is calculated. Finally, in step ST34, FIG.
The constant temperature T can be found by comparing the amount of decrease with the calculated value.

FIG. 28 is a flowchart showing a procedure for measuring the temperature of the wafer surface from the recovery rate during annealing at a constant temperature using the data of FIG.

First, in step ST41, an amorphous region having a thickness of d0 is formed. Next, in step ST42, at a certain temperature T, a certain time t is changed to t1, t2, t3 to perform a heat treatment (annealing), and the thickness d1, d2, d3 of the amorphous region at that time is changed. Measure. Then, in step ST43, the recovery rate r of the amorphous region (= d0−d1 / t1, d0−d2 / t2,
Calculate d0−d3 / t3. Finally, in step ST44, FIG.
By comparing the recovery rate of (or FIG. 19) with the recovery rate r obtained as a result of the calculation, the constant temperature T can be found.
In addition, since the film thickness at any point is known when looking at the recovery rate, even if FIG. 18A is used, the annealing temperature can be known if the amount of reduction in the thickness of the amorphous region is known. For example, if it is found from the measurement that the initial thickness is 44.8 nm and the thickness after annealing for 10 seconds is 32 nm, the data as shown in FIG. It can be determined that the annealing is at 550 ° C.

FIG. 29 is a flowchart showing a procedure for measuring the temperature of the wafer surface from the recovery rate during annealing for a certain period of time by preparing the data of FIG. 18 for many annealing temperatures.

First, in step ST51, an amorphous region having a thickness of d0 is formed. Next, in step ST52, a heat treatment (annealing) is performed under a certain fixed time t while changing a certain temperature T to T1, T2, T3, and the thickness d1, d2, d3 of the amorphous region at that time is determined. Measure. Then, in step ST53, the recovery rate r of the amorphous region (= d0−d1 / t, d0−d2 / t, d0)
Calculate -d3 / t. Finally, in step ST54, by selecting a temperature indicating the recovery rate that best matches the calculated recovery rate r from among many data indicating the recovery rate as shown in FIG. You will understand.

-Fifth specific example-Next, a fifth specific example relating to measurement of a temperature distribution in a wafer or a chamber using spectroscopic ellipsometry will be described.

FIG. 21 is a thickness distribution diagram showing the in-plane uniformity of the amorphous region in the wafer in the state shown at point A16 in FIG. At this time, the average thickness is 44.785 nm, and the point A16 in FIG.
Is equal to the thickness value. The thickness at each point on the wafer indicates whether the thickness is larger (indicated by +) or small (indicated by-) than the average value. Also, FIG.
FIG. 17 is a thickness distribution diagram of an amorphous region in the wafer in a state indicated by point C16 in FIG. As in FIG. 21, the thickness at each point on the wafer is larger than the average value (indicated by +).
Or the thickness is small (indicated by-). The average thickness at this time is 43.059 nm, which is equal to the thickness value at point C16 in FIG. It can be seen that the state of the thickness distribution shown in FIG. 22 is completely different from the state of the thickness distribution shown in FIG. FIG. 23 is a distribution diagram of a value obtained by subtracting the thickness of each measurement point shown in FIG. 21 from the thickness of each measurement point shown in FIG. 22, and shows a change in the thickness of each measurement point during 30 seconds. The amount of thickness reduction is
It is a film thickness changed from amorphous to crystalline, and shows how the amount of reduction is distributed with respect to an average value (shown by a thick line) in the wafer surface.

Thus, by obtaining the distribution of the reduced film thickness, the temperature distribution in the wafer surface can be known. More specifically, the annealing time is 30 seconds, and the change in average film thickness is A16 (44.785 nm) -C16 (43.059n).
m), the reduced film thickness is (44.785-43.05).
9) = 1.726 nm, so that the annealing temperature (here, 275 ° C.) can be obtained from FIG. 20, and at the same time, the temperature distribution in the wafer surface can be found from the distribution of the decrease in the film thickness in the wafer surface. .

—Sixth Specific Example— Next, a sixth specific example relating to measurement of film quality distribution in a wafer or a chamber using spectroscopic ellipsometry will be described.

FIG. 24 is a distribution diagram of the absorption coefficient of the amorphous region in the wafer in the state shown at point A16 in FIG. Since a large absorption coefficient means that the transparency of the amorphous region is high (amorphous region close to a crystal), the film quality of the amorphous region can be determined from the absorption coefficient. The film quality is a criterion for judging the difference because some of the amorphous materials have small irregularities and are closer to crystals, while others have large irregularities and a large degree of amorphousness. FIG. 25 is a view similar to that of FIG.
FIG. 14 is a distribution diagram of an absorption coefficient of an amorphous region in a wafer in a state indicated by C16.

Also in this specific example, the distribution of the recovery state of the film quality in the amorphous region due to the annealing can be understood from the distribution of the absorption coefficient. That is, conventionally, it has been impossible to evaluate the in-plane uniformity of the recovery state of the film quality of the amorphous region in the low-temperature annealing. However, according to the present invention, the in-plane non-uniformity of the film quality of the amorphous region can be evaluated.

Then, by using the value of the absorption coefficient and the distribution of the absorption coefficient in the wafer surface, for example, the film quality of a region where silicide is formed (source / drain region of a MOS transistor) can be evaluated.

For example, in the salicide process, the film quality of the underlying semiconductor layer (source region, drain region, gate region) affects the reactivity of silicidation, and therefore, it is necessary to grasp the film quality of the semiconductor layer before silicidation. It becomes important. Therefore, before depositing the titanium film on the ion-implanted semiconductor layer (for example, the source / drain region), the absorption coefficient of the semiconductor layer is measured, and the grain size of the silicide formed later, By grasping the relationship with the progress of the process, management for optimizing the silicide process can be performed.

(Third Embodiment) In the present embodiment, a method of managing a manufacturing process using the first to sixth specific examples of the first embodiment or the second embodiment will be described.

-First Specific Example- FIGS. 26 (a) and 26 (b) are flowcharts showing two methods for managing the ion implantation process using the measurement of the thickness of the amorphous region according to the first embodiment. It is.

According to the method shown in FIG. 26A, in step ST11, the substrate having the semiconductor layer is cleaned, and in step ST12
In the above, ion implantation is performed in the semiconductor layer to form an amorphous region in the semiconductor layer. Next, in step ST13, it is determined whether or not the thickness of the amorphous region is within an appropriate range. In this determination, if the thickness of the amorphous region is within the appropriate range, the process proceeds to the next step, step ST14, where a heat treatment for ion activation is performed. On the other hand, if it is determined in step ST13 that the thickness of the amorphous region is not within the appropriate range, the substrate is put into lot out.

According to this method, it is possible to avoid unnecessary processing after the step of processing a defective substrate.

According to the method shown in FIG. 26 (b), in step ST21, the substrate having the semiconductor layer is cleaned, and step ST22 is performed.
In the above, ion implantation is performed in the semiconductor layer to form an amorphous region in the semiconductor layer. Next, in step ST23, it is determined whether or not the thickness of the amorphous region is within an optimum range where the implantation conditions need not be changed. In this determination, if the thickness of the amorphous region is within the optimum range, the process proceeds to the next step, Step ST24, without taking any measure, and heat treatment for ion activation is performed.
On the other hand, if it is determined in step ST23 that the thickness of the amorphous region is within the optimal reaction, the implantation conditions in step ST22 are changed so that the thickness of the amorphous region falls within the optimal range (increase the implantation energy).

According to this method, the ion implantation conditions in the ion implantation step can be kept as optimal as possible, and the yield can be improved and the subsequent steps can be stabilized by reducing the variation in the thickness of the amorphous region.

In step ST23, it is determined whether or not the thickness of the amorphous region is equal to or larger than the lower limit. If the thickness of the amorphous region is equal to or larger than the lower limit, the next step, step ST23, is performed.
Proceeding to 24, if the thickness of the amorphous region is smaller than the lower limit, the process may return to step ST22 to perform additional implantation.

-Second Specific Example-In this specific example, a method for managing a film forming process will be described. In this case, the method is divided into the following two methods.

In the first method, a polysilicon film, a metal film, an insulating film, and the like are deposited on an amorphous region of a substrate by CVD or sputtering, and then the film is removed by, for example, wet etching. Then, by performing spectral ellipsometry measurement before and after performing CVD or sputtering and comparing the thickness of the amorphous region before and after the processing, the temperature and temperature distribution during CVD and sputtering can be determined. Even if the removal of the film has an effect on the underlying amorphous region, data errors due to the effect on the underlying may be corrected by repeating experiments. That is, the shaved thickness of the amorphous region can be calculated from the etching rate when the amorphous region is removed. It is difficult or difficult to conduct an experiment to confirm the thickness at which the amorphous region is shaved, and by subtracting the thickness, an accurate CVD temperature and sputtering temperature can be detected.

In the second method, when the film to be formed is transparent to the measurement light (for example, a silicon oxide film or a silicon nitride film), a state in which a transparent film is formed on the amorphous region, that is, This method detects the substrate surface temperature during film formation by measuring the thickness of the amorphous region in the state of a two-layer film.

Conventionally, there is no effective means for detecting the surface temperature of the substrate during CVD or sputtering, but by using the first to sixth specific examples of the second embodiment, a wide range from high-temperature CVD to low-temperature CVD The substrate surface temperature can be detected in various types of CVD. Therefore, it is possible to appropriately set the temperature for maintaining the temperature at the time of performing the CVD properly, specifically, the plasma power and the like.
Further, the temperature distribution in the chamber during CVD can be detected.

Note that, in any of the first and second methods, when high-temperature heat treatment is involved, the data in FIG. 19 can be used.

Also, when the resist is ashed, the temperature is raised to about 300 ° C., so that the temperature at that time can be detected by measuring the thickness of the amorphous region.

(Other Embodiments) Measurement of the thickness, film quality, and annealing temperature of the amorphous region in each of the above embodiments can be automatically performed by recording the procedure on a recording medium.

For example, the procedures of the first to fifth methods described in the first specific example of the first embodiment (for example, procedures shown in FIGS. 31 and 32)
Is recorded as a program on a computer-readable recording medium, the thickness of the region that has been made amorphous by ion implantation can be automatically detected.

Furthermore, by recording the procedure for performing temperature measurement using the thickness of the amorphous region shown in the second embodiment (for example, the procedure in FIGS. 27 to 29) as a program on a computer-readable recording medium, Can automatically detect the temperature.

[Industrial application field] The present invention relates to various transistors mounted on electronic devices,
It can be used to manufacture a semiconductor device such as a semiconductor memory.

Continuation of the front page (56) References JP-A-6-77301 (JP, A) JP-A-5-249031 (JP, A) JP-A-6-50880 (JP, A) JP-B-59-50927 (JP, A) , B1) JP-A-4-501175 (JP, A) Siemens Forsch. -U. Entwickl. -Ber. B d. 10 (1981) Nr. 1, p48-52, Nuclear Instruments and Methods in Physics Research B19 / 20 (1987) p577-581 Mat. Res. Soc. Symp. Proc. [38] (1985) P417-423 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/00-21/61 G01B 11/06 EPAT (QUESTEL) JICST file (JOIS) WPI / L ( QUESTEL)

Claims (15)

(57) [Claims] 1. A semiconductor layer having a region into which impurity ions are implanted in a substrate, a p-direction (an intersection of a plane perpendicular to the optical axis with a plane containing incident light and reflected light) in a plane perpendicular to the optical axis. The direction of the linearly polarized measurement light inclined with respect to the direction perpendicular to the surface of the semiconductor layer in the direction perpendicular to the optical axis. At least cos Δ, where Δ is a phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. A second step, a third step of measuring the spectrum of at least cos Δ according to a change in the wavelength of the measurement light, and a step of measuring the spectrum of at least cos Δ based on the spectrum of at least cos Δ. The thickness of the amorphous region A fourth step of generating a first correlation between the implantation energy at a specific ion implantation amount and the thickness of the amorphous region as a first correlation for each ion implantation amount. And a step of preparing in advance a relationship between the energy and the implantation energy as a second correlation. In the fourth step, the spectrum of cos Δ obtained in the second step is converted into the second correlation. Measuring the thickness of the amorphous region in the semiconductor layer by determining the implantation energy of the ions implanted into the semiconductor layer by comparing the implantation energy with the first correlation. A method for evaluating a semiconductor layer, comprising: 2. A semiconductor layer having a region into which impurity ions are implanted in a substrate, in a p-direction (an intersection between a plane perpendicular to the optical axis and a plane containing incident light and reflected light) in a plane perpendicular to the optical axis. The direction of the linearly polarized measurement light inclined with respect to the direction perpendicular to the surface of the semiconductor layer and the direction of the linearly polarized light inclined with respect to the direction of the line) and the direction s (the direction perpendicular to the p direction in a plane perpendicular to the optical axis). At least cos Δ, where Δ is a phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. A second step, a third step of measuring the spectrum of at least cos Δ according to a change in the wavelength of the measurement light, and a step of measuring the spectrum of at least cos Δ based on the spectrum of at least cos Δ. The thickness of the amorphous region Together and a fourth step of leaving, as the first correlation the relationship between the thickness of the ion dose and amorphous regions in particular implantation energy for each implantation energy, cos delta at a particular implant energy
And a step of preparing in advance a relationship between the spectrum and the ion implantation amount as a second correlation. In the fourth step, the spectrum of cos Δ obtained in the second step is converted into the second correlation. After obtaining the implantation amount of the ions implanted into the semiconductor layer by comparing the correlation with the correlation, the thickness of the amorphous region in the semiconductor layer is reduced by comparing the ion implantation amount with the first correlation. A method for evaluating a semiconductor layer, comprising measuring. 3. A semiconductor layer having a region into which impurity ions are implanted in a substrate, in a p-direction (an intersection between a plane perpendicular to the optical axis and a plane containing incident light and reflected light) in a plane perpendicular to the optical axis. The direction of the linearly polarized measurement light inclined with respect to the direction perpendicular to the surface of the semiconductor layer and the direction of the linearly polarized light inclined with respect to the direction of the line) and the direction s (the direction perpendicular to the p direction in a plane perpendicular to the optical axis). At least cos Δ, where Δ is a phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. A second step, a third step of measuring the spectrum of at least cos Δ according to a change in the wavelength of the measurement light, and a step of measuring the spectrum of at least cos Δ based on the spectrum of at least cos Δ. The thickness of the amorphous region And changing the implantation energy at a constant ion implantation amount, wherein the relationship between the implantation energy at a specific ion implantation amount and the thickness of the amorphous region is a first correlation for each ion implantation amount. Further comprising the step of preparing in advance a relationship between the wavelength indicating the maximum value of cos Δ in a predetermined wavelength region in the spectrum of cos Δ at the time of injection and the injection energy as a second correlation, the fourth step Then, the spectrum of cos Δ obtained in the second step is compared with the second correlation to determine the implantation energy of the ions implanted into the semiconductor layer. Measuring the thickness of the amorphous region in the semiconductor layer by comparing with the correlation of Evaluation method. 4. A semiconductor layer having a region into which impurity ions are implanted in a substrate, a p-direction (an intersection between a plane perpendicular to the optical axis and a plane containing incident light and reflected light) in a plane perpendicular to the optical axis. The direction of the linearly polarized measurement light inclined with respect to the direction perpendicular to the surface of the semiconductor layer in the direction perpendicular to the optical axis. At least cos Δ, where Δ is a phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. A second step, a third step of measuring the spectrum of at least cos Δ according to a change in the wavelength of the measurement light, and a step of measuring the spectrum of at least cos Δ based on the spectrum of at least cos Δ. The thickness of the amorphous region And a fourth step of performing the first step, wherein the relationship between the implantation amount at a specific implantation energy and the thickness of the amorphous region is set as a first correlation for each implantation energy, and the implantation amount is changed while the implantation energy is constant. in a given wavelength region in the spectrum of cos Δ
The method further includes a step of preparing in advance a relationship between the wavelength indicating the maximum value of cos Δ and the injection amount as a second correlation. In the fourth step, the cos Δ obtained in the second step is obtained. After the amount of ions implanted into the semiconductor layer is determined by comparing the spectrum to the second correlation, the amount of ions implanted into the semiconductor layer is determined by comparing the amount of ions implanted to the first correlation. 3. A method for evaluating a semiconductor layer, comprising measuring a thickness of an amorphous region. 5. The method for evaluating a semiconductor layer according to claim 1, wherein the first to fourth steps are performed on a region in the semiconductor layer into which a plurality of impurity ions have been implanted. Measuring the thickness distribution of the amorphous region in the region into which the impurity ions have been implanted in the semiconductor layer. 6. A semiconductor layer having a region into which impurity ions have been implanted in a substrate, in a direction perpendicular to an optical axis in a p-direction (intersection between a plane perpendicular to the optical axis and a plane containing incident light and reflected light). The direction of the linearly polarized measurement light inclined with respect to the direction perpendicular to the surface of the semiconductor layer in the direction perpendicular to the optical axis. At least cos Δ, where Δ is a phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer. A second step, a third step of measuring the spectrum of at least cos Δ according to a change in the wavelength of the measurement light, and a step of measuring the spectrum of at least cos Δ based on the spectrum of at least cos Δ. The thickness of the amorphous region And a first step of obtaining the first thickness of the amorphous region by performing the first to fourth steps on the semiconductor layer before the heat holding process. Performing a first to fourth steps on the semiconductor layer to obtain a second thickness of the amorphous region after performing the heat holding process; and a first thickness, a second thickness and a second thickness of the amorphous region. Measuring the temperature of the heat holding process from a recovery rate calculated from the time of the heat holding process. 7. The method for evaluating a semiconductor layer according to claim 6, further comprising a step of obtaining a correlation between a temperature of the heat holding process in the heat holding process and a decrease in the thickness of the amorphous region. In the step, a method for evaluating a semiconductor layer, comprising measuring a temperature of the heat holding process based on the correlation. 8. The method for evaluating a semiconductor layer according to claim 6, wherein the measurement of the heat holding processing temperature is performed for a plurality of amorphous regions in the substrate, and the heat holding temperature in the plurality of amorphous regions is determined based on the heat holding temperature in the plurality of amorphous regions. Alternatively, a method for evaluating a semiconductor layer, comprising measuring a temperature distribution in a processing apparatus. 9. A method for manufacturing a semiconductor device in a semiconductor layer of a substrate, comprising: a first step of implanting impurity ions into the semiconductor layer to form an amorphous region having disordered crystallinity; A second step of performing a process involving maintaining the region at a predetermined temperature; and a p-direction (a plane perpendicular to the optical axis and a plane including incident light and reflected light) in a plane perpendicular to the optical axis on the semiconductor layer. The direction of the intersection of
Linearly polarized measurement light inclined in a direction (in a plane perpendicular to the optical axis and perpendicular to the p-direction) in a direction inclined to a direction perpendicular to the surface of the semiconductor layer; Assuming that the phase difference between the p component and the s component in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer is Δ, the spectrum of at least cos Δ before and after the processing in the second step A fourth step of measuring a change in the thickness of the amorphous region before and after the processing in the second step, based on the change in the spectrum of at least cos Δ; A fifth step of measuring the temperature of the heat holding process from a change in thickness of the region before and after the process and a recovery rate calculated from the time of the heat holding process. The method of manufacturing a semiconductor device according to claim Rukoto. 10. The method of manufacturing a semiconductor device according to claim 9, further comprising a step of obtaining a correlation between a temperature of the heat holding process in the heat holding process and a decrease in the thickness of the amorphous region. In the step, the temperature of the heat holding process is measured based on the correlation. 11. A semiconductor layer having an amorphous region in which crystallinity is disturbed by impurity ions implanted in a substrate, in a p-direction (a plane perpendicular to the optical axis and incident light and reflected light) in a plane perpendicular to the optical axis. The direction perpendicular to the surface of the semiconductor layer is a linearly polarized measurement light inclined with respect to the direction of the line of intersection with the plane including the surface and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). When the phase difference between the p component and the s component is Δ in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer, A recording medium used to evaluate a physical quantity of the amorphous region from at least a cos Δ spectrum with a change in wavelength, wherein a correlation between the thickness of the amorphous region and the at least cos Δ spectrum is stored. Step 1 and At least cos, which is the result of spectroscopic ellipsometry measurement of the amorphous region formed under specific implantation conditions
A second procedure of inputting a spectrum of Δ, extracting the correlation, and comparing at least the spectrum of cos Δ obtained in the second step with the correlation to obtain an amorphous region in the semiconductor layer. In addition to recording a program for causing a computer to execute a third procedure for measuring the thickness of the semiconductor substrate and the first procedure, the first procedure describes a relationship between the implantation energy at a specific ion implantation amount and the thickness of the amorphous region for each ion implantation amount. As the first correlation, the relationship between the spectrum of cos Δ and the implantation energy at a specific ion implantation amount is stored as a second correlation, and in the third procedure, the relationship is input in the second procedure. Cos
After determining the implantation energy of the ions implanted into the semiconductor layer by comparing the spectrum of Δ with the second correlation, the semiconductor layer is determined by comparing the implantation energy with the first correlation. A recording medium characterized by measuring the thickness of an amorphous region in the inside. 12. A semiconductor layer having an amorphous region in which impurity ions are implanted in a substrate and having disordered crystallinity, in a direction perpendicular to the optical axis in a p-direction (a plane perpendicular to the optical axis and incident light and reflected light). The direction perpendicular to the surface of the semiconductor layer is a linearly polarized measurement light inclined with respect to the direction of the line of intersection with the plane including the surface and the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis). When the phase difference between the p component and the s component is Δ in the reflected light of the measurement light reflected as elliptically polarized light from the semiconductor layer, A recording medium used to evaluate a physical quantity of the amorphous region from at least a cos Δ spectrum with a change in wavelength, wherein a correlation between the thickness of the amorphous region and the at least cos Δ spectrum is stored. Step 1 and At least cos, which is the result of spectroscopic ellipsometry measurement of the amorphous region formed under specific implantation conditions
A second procedure of inputting a spectrum of Δ, extracting the correlation, and comparing at least the spectrum of cos Δ obtained in the second step with the correlation to obtain an amorphous region in the semiconductor layer. In addition to recording a program for causing a computer to execute a third procedure for measuring the thickness of the amorphous silicon layer and the third procedure, the first procedure includes, for each implantation energy, the relationship between the ion implantation amount at a specific implantation energy and the thickness of the amorphous region. As the first correlation, the relationship between the spectrum of cos Δ at a specific implantation energy and the ion implantation amount is stored as a second correlation, and in the third procedure, the correlation is inputted in the second procedure. cos
The amount of ions implanted into the semiconductor layer is determined by comparing the spectrum of Δ with the second correlation, and then the amount of ions implanted into the semiconductor layer is compared with the first correlation to obtain the semiconductor. A recording medium for measuring the thickness of an amorphous region in a layer. 13. A semiconductor layer having an amorphous region in which crystallinity is disordered by implanting impurity ions in a substrate, and heat-treating the semiconductor layer in a direction p (plane perpendicular to the optical axis) in a plane perpendicular to the optical axis. The direction of the line of intersection between the light and the plane containing the incident light and the reflected light) and the linearly polarized measurement light inclined with respect to the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis) are transmitted to the semiconductor layer. Of the measurement light reflected from the semiconductor layer as elliptically polarized light from the direction perpendicular to the surface of
And a recording medium used to measure the temperature of the heat treatment from at least the spectrum of cos Δ with the change in the wavelength of the measurement light, wherein the heat treatment time at a specific temperature and the amorphous state A first procedure for storing the relationship with the amount of decrease in the thickness of the region as a correlation; a second procedure for storing the thickness of the amorphous region before the heat treatment; and the thickness of the amorphous region after the heat treatment. And extracting the correlation between the thickness of the amorphous region before and after the heat treatment and the correlation, and comparing the amount of decrease in the thickness of the amorphous region before and after the heat treatment with the correlation to obtain the heat treatment temperature. A computer-readable recording medium characterized by recording a program for causing a computer to execute the procedure for determining . 14. A semiconductor layer having an amorphous region in which crystallinity is disordered by implanting impurity ions in a substrate, and heat-treating the semiconductor layer so that the semiconductor layer has a p-direction (plane perpendicular to the optical axis) in a plane perpendicular to the optical axis. The direction of the line of intersection between the light and the plane containing the incident light and the reflected light) and the linearly polarized measurement light inclined with respect to the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis) are transmitted to the semiconductor layer. Of the measurement light reflected from the semiconductor layer as elliptically polarized light from the direction perpendicular to the surface of
And a recording medium used to measure the temperature of the heat treatment from at least the spectrum of cos Δ with the change in the wavelength of the measurement light, wherein the heat treatment time at a specific temperature and the amorphous state A first procedure for storing the recovery rate obtained from the relationship with the amount of decrease in the thickness of the region as a correlation for each temperature; a second procedure for storing the thickness of the amorphous region before the heat treatment; Extracting a third procedure for storing the thickness of the amorphous region after the heat treatment and the heat treatment time, and extracting the correlation between the thickness decrease before and after the heat treatment of the amorphous region and the correlation, and calculating the decrease amount of the thickness of the amorphous region before and after the heat treatment. By comparing the recovery rate obtained by dividing the heat treatment time by the heat treatment time with the above correlation, a fourth procedure for obtaining the heat treatment temperature is performed. A computer-readable recording medium characterized by recording a program to be executed by the computer. 15. A semiconductor layer having an amorphous region in which crystallinity is disordered by implanting impurity ions in a substrate, and heat-treats the semiconductor layer in a direction perpendicular to the optical axis in a p-direction (plane perpendicular to the optical axis). The direction of the line of intersection between the light and the plane containing the incident light and the reflected light) and the linearly polarized measurement light inclined with respect to the s direction (the direction perpendicular to the p direction in the plane perpendicular to the optical axis) are transmitted to the semiconductor layer. The measurement light of linearly polarized light inclined to a direction perpendicular to the surface of the semiconductor layer is incident from a direction inclined to the direction perpendicular to the surface of the semiconductor layer, and the measurement light reflected as elliptically polarized light from the semiconductor layer is reflected from the semiconductor layer. When the phase difference between the p component and the s component of the reflected light is represented by Δ, a recording medium used for measuring the temperature of the heat treatment from at least cos Δ spectrum accompanying a change in the wavelength of the measurement light. Heat treatment under a specific time A first procedure for storing a recovery rate obtained from a relationship between the temperature of the amorphous region and a change in the thickness of the amorphous region as a correlation; a second procedure for storing the thickness of the amorphous region before the heat treatment; and a heat treatment for the amorphous region. A third procedure for storing the thickness and the heat treatment time after the heat treatment, and the correlation between the thickness decrease before and after the heat treatment of the amorphous region and the correlation are taken out. A computer-readable recording medium characterized by recording a program for causing a computer to execute the above-mentioned procedure for obtaining the heat treatment temperature by comparing the recovery rate obtained by dividing by the above correlation with the above correlation.