JP3305310B1 - Temperature measurement method - Google Patents

Abstract

An object of the present invention is to provide a temperature measuring method capable of measuring a temperature and a temperature distribution in a chamber with high accuracy, and a method for preparing a sample suitable for temperature measurement. SOLUTION: Silicon substrate 1 having natural oxide film 11
When As is implanted into 0, an amorphous region 10a is formed, and the amorphous region 10a is divided into a high-concentration oxygen region 10aa having an oxygen concentration higher than a critical value and a low-concentration oxygen region 10ab having an oxygen concentration lower than the critical value. Thereafter, when oxygen ions are implanted, the high-concentration oxygen region 10aa is expanded to the entire amorphous region. After annealing,
The recovery rate is determined by utilizing the decrease in the thickness of the amorphous region. Further, the annealing temperature is determined by using the relationship between the annealing temperature and the recovery rate. By adjusting the oxygen concentration in the amorphous region to be equal to or higher than the critical value, the recovery rate can be set to a substantially constant small value, and the accuracy and reliability of the temperature measurement are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring method for measuring a temperature and a temperature distribution in a predetermined region in a chamber,
The present invention relates to a method for manufacturing a semiconductor device using a method for preparing a sample and a method for measuring temperature.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, CVD, ion implantation, heat treatment (annealing),
Processes such as plasma etching are performed, and by these processes, film formation on the wafer, introduction of impurities into the wafer, formation of a diffusion layer by activating the impurities, patterning of the formed film, and the like are performed. In this case, these processes must be performed under appropriate conditions defined respectively, and one of the conditions is temperature. In particular, the temperature at a certain position of a wafer installed in the chamber, the temperature distribution in the wafer surface, and the like are important parameters for managing a CVD process, a heat treatment process, and the like.

Therefore, conventionally, various methods have been adopted as a method for measuring the temperature and the temperature distribution during each processing in the manufacturing process.

For example, a thermocouple is attached to a chamber for performing an RTA process as a high-speed heating process, or a thermocouple attached to a back surface of a wafer (TC wafer) is used. There is also known a method of measuring the temperature in a chamber by optical measurement using infrared detection or the like.

[0005]

However, the conventional temperature measuring method has the following disadvantages.

For example, in the temperature measurement using a TC wafer, the temperature on the back surface of the wafer can be detected, but the temperature on the upper surface of the wafer is not known. Also, there is a limit to the temperature measurement range, and it is said that the measurement accuracy deteriorates when the temperature reaches a certain high temperature (500 to 600 ° C. or higher).

In the case of optical measurement, there is a problem that accurate temperature measurement cannot be performed because optical noise and the like are generated due to the influence of plasma. Furthermore, it was not possible to measure even the temperature distribution in the plane of the wafer just by knowing the temperature values of only limited points.

In particular, regarding the temperature distribution in the wafer surface,
Even with a TC wafer, it has been difficult to perform highly reliable temperature distribution measurement.

A first object of the present invention is to pay attention to the fact that the progress of recovery by annealing of a portion which has been changed from a single crystal state into an amorphous region by ion implantation has temperature dependency and ion implantation condition dependency. Another object of the present invention is to measure the thickness of an amorphous region by using spectroscopic ellipsometry and the like, convert the thickness into a temperature, measure the temperature, and improve the accuracy of the temperature measurement.

[0010] In addition, in the process of improving the accuracy of temperature measurement using spectroscopic ellipsometry, the present inventors
It has been found that the process for improving the accuracy of the temperature measurement and the improvement of the shape of the amorphous region have a strong relationship with each other. Accordingly, a second object of the present invention is to improve the conditions of pre-amorphous implantation performed for preventing channeling and as one of pretreatments for silicidation based on this discovery.

[0011]

A first temperature measuring method according to the present invention comprises the steps of: (a) doping oxygen into an amorphous region formed in a semiconductor region of a substrate; and heating the amorphous region for a predetermined time. (B) obtaining a recovery rate at which the amorphous region is recrystallized, and the temperature of the amorphous region in the step (b) based on the previously prepared relationship between the recovery rate of the amorphous region and the heating temperature. (C).

According to this method, the recovery rate when the amorphous region is heated can be adjusted by the oxygen concentration, and the temperature can be measured in a desired temperature range.

In the step (a), the recovery rate, that is, the temperature is measured by doping oxygen so as to reach a critical value for making the recovery rate in the step (b) substantially constant from the start of heating. It is easy and reliable.

If an oxide film is formed on the semiconductor region of the substrate before performing the step (a), ion implantation of impurities into the semiconductor region is performed before the step (a). The method may further include a step of forming the amorphous region by performing.

According to this method, it is possible to avoid the adverse effect of oxygen that has been knocked on by the implantation of impurity ions and has entered the amorphous region.

Further, before the step shown in the step (a), the method further includes a step of removing a native oxide film on the semiconductor region under reduced pressure, and the step (a) removes the native oxide film. After the step, the oxygen concentration can be more reliably controlled to a desired value by performing the process while keeping the substrate under reduced pressure without exposing the substrate to the atmosphere.

The step (b) is performed by using the thickness measurement of the amorphous region by the spectroscopic ellipsometry, so that the temperature measurement can be performed in-line.

According to a second temperature measuring method of the present invention, a step (a) of forming an amorphous region by ion implantation of a group IV element into a semiconductor region of a substrate, and heating the amorphous region for a predetermined time Step (b) for obtaining a recovery rate at which the amorphous region is recrystallized, and obtaining the temperature of the amorphous region in step (b) based on a previously prepared relationship between the recovery rate of the amorphous region and the heating temperature. Step (c).

According to this method, an amorphous region can be formed without affecting the conductivity type of the semiconductor region.

In the above step (a), the dose is 1 ×
By performing, for example, Ge ion implantation under the condition of 10 ¹⁵ atoms · cm ⁻² or more, the boundary between the amorphous region and the crystalline region in the semiconductor region can be clarified, and the accuracy and reliability of the temperature measurement can be improved. improves.

According to a third temperature measuring method of the present invention, at least one of arsenic (As), phosphorus (P), a halogen element and an inert gas element is implanted into a semiconductor region of a substrate. Forming an amorphous region (a), heating the amorphous region for a certain period of time to obtain a recovery rate at which the amorphous region is recrystallized, and preparing a recovery rate of the amorphous region and heating prepared in advance. A step (c) of obtaining the temperature of the amorphous region in the step (b) based on the relationship with the temperature.

According to this method, it is possible to improve the accuracy and reliability of temperature measurement, which leads to an extension of the maintenance cycle and a reduction in the number of devices, without using a corrosive gas such as GeF ₄ .

A fourth temperature measuring method according to the present invention comprises the steps of: (a) forming a plurality of amorphous regions by ion-implanting a plurality of locations in a semiconductor region of a substrate under different conditions; (B) individually obtaining a recovery rate at which each of the amorphous regions is recrystallized by heating the region for a certain period of time; and, based on a relationship between a previously prepared recovery rate of each of the amorphous regions and a heating temperature, A step (c) of obtaining a temperature of each amorphous region in the step (b) corresponding to each recovery rate.

According to this method, it is possible to extend the range in which temperature measurement can be performed by utilizing a plurality of amorphous regions having different temperature measurement ranges with high reliability. Can be detected.

In the step (a), it is preferable that ion species to be implanted into the plurality of locations or ion implantation conditions be different.

The above-mentioned substrate is in a wafer state, and the above step (a) is performed by using a sample in which the above-mentioned four portions are divided into four upper, lower, left, and right parts in a plan view. When the temperature in a certain process is unknown, near the temperatures revealed from the data of the recovery rates at four locations, thereafter, only one type of ion implantation is performed on the entire wafer to measure the detailed temperature distribution and the like. It is possible to do.

According to a fifth temperature measuring method of the present invention, a step (a) of forming a first amorphous region by ion implantation into a first semiconductor region on an upper surface of a substrate; (B) forming the second amorphous region by performing the above-described ion implantation on the second semiconductor region; and recovering the first amorphous region and not recovering the second amorphous region in the substrate. Heating under the condition to obtain the recovery rate of the first amorphous region (c); and performing the step (c) based on the relationship between the previously prepared recovery rate of the first amorphous region and the heating temperature. determining the temperature of the first amorphous region in c) (d)
And

According to this method, after measuring the temperature of the first amorphous region and then heating the substrate under the condition that the second amorphous region recovers, the temperature measurement in the two temperature regions can be performed using one substrate. Will be possible. In particular, when a large-diameter wafer is used, the thickness of the wafer increases, so that even when the wafer is heated to a temperature at which the first amorphous region on the upper surface of the wafer is recovered, the back surface may not reach that temperature. This temperature measurement method can reduce the number of measurement samples.

According to a sixth temperature measuring method of the present invention, a step (a) of forming a first amorphous region by ion implantation into a first semiconductor region on an upper surface of a substrate; (B) forming the second amorphous region by performing the above-described ion implantation in the second semiconductor region; and heating the substrate to recover the first and second amorphous regions and to form the second amorphous region. (C) obtaining the recovery rates of the first and second amorphous regions, respectively, and the respective recovery rates based on the relationship between the previously prepared recovery rates of the first and second amorphous regions and the heating temperature. (D) determining the temperatures of the first and second amorphous regions in the above step (c) corresponding to the step (c), and calculating the temperature of the substrate from the temperature difference between the first and second amorphous regions. Determining a conductivity (e)
And

According to this method, since the thermal conductivity of the substrate is known, the temperature of each part of the substrate can be controlled, and the yield can be improved and the quality of the product device can be improved. In particular, when the diameter of the wafer is increased, the thickness of the wafer increases, so that the process control can be properly performed by knowing the thermal conductivity.

A seventh temperature measuring method according to the present invention comprises the steps of: (a) forming an amorphous region in a semiconductor region of a substrate by performing ion implantation under a condition that the substrate temperature is lower than −10 ° C. (B) obtaining a recovery rate at which the amorphous region is recrystallized by heating the amorphous region for a predetermined time; and (b) based on a relationship between the previously prepared recovery rate of the amorphous region and the heating temperature. And (c) for determining the temperature of the amorphous region.

According to this method, the temperature can be measured in a state where a clear boundary exists between the amorphous region and the crystalline region in the semiconductor region or in a state where the unevenness of the interface is small, and the accuracy and reliability of the temperature measurement can be improved. The performance is improved.

According to an eighth temperature measuring method of the present invention, there is provided a step (a) of forming an amorphous region by performing ion implantation in a semiconductor region of a substrate, and forming the amorphous region in a range of 300 ° C. to 450 ° C. Annealing at a temperature (b), heating the amorphous region to determine a recovery rate at which the amorphous region is recrystallized (c), and preparing a recovery rate and heating temperature of the amorphous region prepared in advance. Based on the relationship
And (d) obtaining the temperature of the amorphous region in step (c).

According to this method, the temperature can be measured in a state where a clear boundary exists between the amorphous region and the crystalline region in the semiconductor region or in a state where the unevenness of the interface is small, and the accuracy and reliability of the temperature measurement can be improved. The performance is improved. .

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION-Principle of Temperature Measurement Using Recovery Rate of Amorphous Region-The present inventors have filed International Application PCT / JP98 / 02567.
As described in (International Publication No. WO 98/57146), a process in which a semiconductor region (amorphous region) into which impurity ions are implanted and made amorphous by annealing is evaluated by spectroscopic ellipsometry, and an amorphous region is evaluated. Since the thickness of the wafer can be detected by in-line non-destructive inspection and the recovery rate, which is the amount of reduction in the thickness of the amorphous region per unit time, depends on the annealing temperature, the recovery rate is determined to determine the wafer surface (wafer thickness). Both the upper and lower surfaces)
It has been found that the actual temperature and temperature distribution can be detected. In other words, it demonstrates that the temperature of the wafer surface can be evaluated by in-line, non-destructive inspection using the spectroscopic ellipsometry method.

Further, the present inventors have made the international application PCT /
In order to improve the accuracy of temperature measurement while presupposing the technique described in JP98 / 02567, the oxygen concentration in the amorphous region and the oxygen concentration in the amorphous region are appropriately adjusted, including elimination of the oxygen injected by knock-on. It was found from the following experiments that the above was effective. However, in order to improve the accuracy of the temperature measurement according to the present invention, it is not always necessary to use the thickness measurement of the amorphous region by spectroscopic ellipsometry. Can be used.

FIG. 1 shows that arsenic ions (A
s ⁺ ) at room temperature, acceleration voltage 30 KeV, dose 4 ×
FIG. 7 is a diagram showing a change over time in the thickness of an amorphous region, that is, a recovery rate when an amorphous region formed by implantation under a condition of 10 ¹⁵ cm ⁻² is annealed at 550 ° C. FIG.
In the graph, the horizontal axis represents the annealing time (sec), and the vertical axis represents the thickness of the amorphous region. In this sample, the result of TEM observation confirmed that the thickness of the amorphous region was 55 nm. Since the recovery rate of the amorphous region by the annealing is the reduction (nm / min) of the thickness per unit time, the slope of the change line shown in FIG. 1 indicates the recovery rate. As shown in FIG. 1, the recovery rate when the thickness of the amorphous region decreases from the initial value of 55 nm to 28 nm is 46.0 (nm / min), and the thickness of the amorphous region decreases from 28 nm to 0 nm. It was found that the recovery rate was 2.8 (nm / min).

Here, it is suspected that the presence of oxygen is involved in such a rapid change in the recovery rate at a certain point in time. Therefore, the oxygen concentration profile in the silicon substrate at this time is considered. Was measured.

FIG. 2 is a diagram showing a concentration profile of arsenic (As) and oxygen (O) in an as-implanted silicon substrate in a substrate depth direction. As shown in the figure, the oxygen concentration, which should be uniform, has a peak value near 1 × 10 ²⁰ atoms · cm ⁻³ near the upper surface of the silicon substrate,
It can be seen that it gradually decreases in the depth direction of the silicon substrate. And originally, about 2.0
Considering that only oxygen of 10 ¹⁸ atoms cm ^-3 is contained, the high concentration of oxygen as shown in FIG. 2 is due to the fact that oxygen atoms knocked on by arsenic ion implantation are present in the silicon substrate. Probably because of intrusion. In other words, when arsenic ions are implanted, the surface of the silicon substrate is cleaned by RCA cleaning or the like, but after being exposed to the air after this RCA cleaning, a natural oxide film is formed on the surface of the silicon substrate. It is considered that oxygen in the natural oxide film was knocked on by the arsenic ions. The oxygen concentration at the position where the recovery rate changes (the position where the thickness of the amorphous region is 28 nm) was about 3.2 × 10 ¹⁹ atoms · cm ⁻³ .

Therefore, as shown in FIG. 3, in order to further examine the relationship between the oxygen concentration and the recovery rate, the oxygen injection amount was increased and the recovery rate was measured. In FIG. 3, the horizontal axis represents the annealing time (sec), and the vertical axis represents the thickness of the amorphous region. Here, the acceleration voltage is 30 k
AsV under the condition of eV and a dose of 4 × 10 ¹⁵ atoms · cm ⁻²
(Indicated by □) and an acceleration voltage of 20 ke in addition to the As ion implantation.
V, a sample obtained by ion implantation of oxygen under the condition of a dose of 1 × 10 ¹⁴ atoms · cm ⁻² (data indicated by a triangle)
In addition to the ion implantation of As, the accelerating voltage is 20 keV,
The measurement results are shown for a sample (data indicated by a circle) in which oxygen ion implantation was performed under the condition of a dose amount of 2 × 10 ¹⁴ atoms · cm ⁻² . At this time, as shown in the figure, when flash annealing (annealing by time change of the temperature at which the holding time at the peak temperature becomes almost zero) is performed on the amorphous region, it is found that the recovery rate becomes slower as the oxygen concentration increases. Was. In each of the three types of samples, the recovery rate changes at a certain value of the thickness of the amorphous region (the thickness of 28 nm shown in FIG. 1), and the oxygen concentration of the portion corresponding to the thickness of the amorphous region is changed. Are 3.2 × 10 ¹⁹ atoms
It was found that the value was close to cm ^-3 .

Here, as shown in FIG.
Recovery rate by flash annealing
As the slope gradually decreases, the recovery
The part where the sheet changes (the value of 28 nm thickness shown in FIG. 1)
It moves up and reaches the position of annealing time 0.
is expected. In other words, the oxygen concentration at which the recovery rate changes
3.2 × 10¹⁹atoms · cm^-3Is the thickness shown in Fig. 1.
It suffices to be at the position of 55 nm. Paraphrase
And a concentration of 3.2 × 10 ¹⁹at
oms ・ cm^-3If the above oxygen is doped, the recovery level
The sheet was estimated to be uniform and small.

If the recovery rate at the time of annealing can be reduced as described above, the influence of the error of the annealing time on the change in the recovery amount of the amorphous region can be reduced, and the accuracy of the temperature measurement can be improved. Hereinafter, a first embodiment for supporting this estimation will be described.

(First Embodiment) FIGS. 4A to 4D
FIG. 3 is a cross-sectional view illustrating a procedure of an annealing process for temperature measurement according to the first embodiment of the present invention. FIG.
FIG. 5 is a flowchart showing a procedure of annealing and temperature measurement. Hereinafter, the procedure of the annealing process in the present embodiment will be described with reference to FIGS. 4A to 4D and along the flowchart of FIG.

First, in step ST11, the silicon substrate 10 is subjected to RCA cleaning. By this cleaning, FIG.
As shown in FIG. 1, the surface of the silicon substrate 10 is cleaned, but a silicon oxide film 11 which is a natural oxide film having a thickness of about 1 nm is formed on the surface of the silicon substrate 10.

Next, in step ST12, silicon oxidation
Arsenic ions (As⁺) At room temperature
Pressure 30 KeV, dose 4 × 10^Fifteencm^-2Injection under the conditions
I do. By this ion implantation, as shown in FIG.
Next, the silicon substrate 10 has a cross section shown in FIG.
Amorph whose crystallinity was disturbed by arsenic ion implantation
Between the ground region 10a and the amorphous region 10a.
To maintain crystallinity without being affected by arsenic ion implantation.
It is divided into the crystal region 10b as it is. At this time,
As mentioned, the silicon oxide film
Oxygen in the substrate is knocked on by arsenic ions,
Will be introduced. And the concentration of knocked-on oxygen is
It decreases as going downward. About this oxygen concentration,
As mentioned above, the critical rate at which the recovery rate during annealing changes
Value (3.2 × 10¹⁹atoms · cm ^-3) May exist
know. Therefore, in this state,
The rufus region 10 a is located directly below the silicon oxide film 11.
Oxygen containing a relatively high concentration of oxygen above the critical value
A region 10aa and a region directly below and relatively below the critical value
Divided into a low-concentration oxygen region 10ab containing low-concentration oxygen
You.

Next, in step ST13, a low-concentration oxygen region 10ab shown in FIG. 4B (a region whose depth position from the upper surface of the silicon substrate 10 is not less than 28 nm and not more than 55 nm).
Oxygen concentration to a critical value (3.2 × 10 ¹⁹ atoms · cm ⁻³ )
In order to achieve the above, oxygen ions are implanted. At this time, the oxygen ion implantation conditions are, for example, room temperature, an acceleration voltage of 20 KeV, and a dose of 2 × 10 ¹⁴ atoms · cm ⁻² or more. By the implantation of the oxygen ions, as shown in FIG.
0a.

Next, in step ST14, annealing at a temperature T is performed. As a result, as shown in FIG. 4D, recrystallization proceeds from the interface between the amorphous region 10a and the crystalline region 10b, and the silicon substrate 1
Within 0, the thickness of the amorphous region 10a decreases, and the crystal region 10b expands upward.

Next, in step ST15, using a spectroscopic ellipsometer, a change in the thickness of the amorphous region 10a within a certain annealing time is detected, and a recovery rate which is a value obtained by dividing the change in the thickness by the annealing time. Ask for.

FIG. 6 shows the amorphous region 10 at this time.
It is a figure which shows the recovery rate to the crystal | crystallization of a. In the figure, the horizontal axis represents the annealing time (second), and the vertical axis represents the amorphous thickness (nm). Amorphous region 1
The thickness of 0a is measured using a spectroscopic ellipsometer described later. As shown in the figure, the thickness of the amorphous region decreases almost linearly with the lapse of the annealing time, and the recovery rate is about 2.8 nm from the slope.
/ Min. This data is the same as the condition under which the data shown in FIG. 1 was obtained after performing As ion implantation under the same conditions as the sample shown in FIG. 1 and then performing oxygen ion implantation to further increase the oxygen concentration. It was obtained by annealing at ℃. Therefore, by adjusting the oxygen concentration of the amorphous region to a certain critical value or more, the recovery rate of the amorphous region at the time of annealing can be set to a substantially constant small value.

Next, in step ST16, referring to the relationship between the previously obtained recovery rate and the annealing temperature T,
The annealing temperature T is determined from the recovery rate obtained in step ST15. At this time, in order to determine the annealing temperature T, the dependence of the recovery rate on the annealing temperature, that is, the relationship between the recovery rate and the annealing temperature T must be known in advance. Therefore, the calculation of the recovery rate and the determination of the annealing temperature T in steps ST15 and ST16 will be described in detail.

FIG. 7 is a flowchart showing a procedure for determining the temperature from the relationship between the annealing temperature T and the recovery rate. FIG. 8 shows Reference 1 (J. Appl. Phys., Vol. 48, No. 10, Oct.
FIG. 9 is a diagram showing the relationship between the recovery rate and the annealing temperature T in a silicon substrate into which high-concentration oxygen is introduced, in addition to the data indicating the relationship between the recovery rate and the annealing temperature T described in Ober 1977). Hereinafter, the procedure up to temperature determination will be described with reference to the flowchart of FIG.

First, in step ST21, a sample for obtaining the relationship between the temperature and the recovery rate is prepared. In this sample, as shown in FIG. 4C, oxygen is introduced into the entire amorphous region at a concentration of 3.2 × 10 ¹⁹ atoms · cm ⁻³ or more.

Next, in step ST22, the relationship between the temperature and the recovery rate is derived. This method is described in International Application P
Employ the method invented by the present inventors disclosed in CT / JP98 / 02567. That is, the thickness of the amorphous region is determined from the shape such as cos Δ using spectral ellipsometry, or further considering the acceleration voltage and the ion implantation amount. As the recovery rate, the recovery rate (L / t) (nm / min) can be calculated from the thickness L nm at which the amorphous region of the sample becomes crystalline at the predetermined time t. Then, by plotting the recovery rates at various annealing temperatures on a graph in which the horizontal axis represents temperature and the vertical axis represents the recovery rate (log scale), a straight line Ko shown in FIG. 8 is created. Also, the equation T = f ｛(L /
By applying this relation to t)｝, a relational expression representing a function of the recovery rate with the annealing temperature as a variable can also be created.

The other straight lines shown in FIG. 8 are data on various samples described in the document. The straight line Ka in the same figure is obtained by implanting phosphorus (P) into the silicon substrate to form an amorphous region and then implanting boron (B), and the straight line Kb is obtained by implanting arsenic (As) into the silicon substrate. And a straight line Kc
Is an amorphous region formed by injecting silicon into a silicon substrate. Therefore, a straight line Ko shown in FIG. 8 can be drawn using the linear relationship in FIG. 8 already obtained by the experiment according to the above-mentioned literature. For example, a straight line Ko can be easily obtained by drawing points at 550 ° C. and 2.8 nm / min from the data shown in FIG. 6 and drawing straight lines parallel to the straight lines Kb and Kc.

Next, in step ST23, a sample for performing actual temperature measurement (temperature value or temperature distribution) on the upper surface of the wafer is prepared. Here, in this specification (including the claims), “temperature measurement” includes at least one of a temperature value and a temperature distribution measurement. This sample has the structure shown in FIG. Then, in step ST24, the recovery rate is calculated using the above-described ellipsometry using the straight line Ko shown in FIG. 8, and the annealing temperature corresponding to the recovery rate value in the straight line Ko is determined. For example, using the straight line Ko, the value of the recovery rate is 20 nm
8, the annealing temperature T is about 610 ° C., as shown in FIG.

According to this embodiment, the temperature of the upper surface of the wafer can be measured using a sample having an amorphous region (ion-implanted region) containing oxygen at a high concentration. In particular, as shown in FIG.
When temperature measurement is performed using (a, Kb, Kc), it is difficult to measure a temperature of 600 ° C. or more even using the straight line Kc. On the other hand, according to the method of the present embodiment, the temperature measurement at a high temperature up to around 650 ° C. can be performed by using the straight line Ko. However, in order to obtain highly reliable data, the limit is around 575 ° C. for the straight line Kc and around 610 ° C. for the straight line Ko. Moreover,
Since the measurement accuracy (reliability) increases as the recovery rate decreases, comparing the measurement accuracy at the same temperature (eg, 550 ° C.), the measurement accuracy is higher when using the straight line Ko than when using the straight line Kc. I understand. In general, if the recovery rate is 100 nm / min or less, there is little error in calculating the recovery rate, and an accurate temperature can be calculated. For this reason, to accurately measure temperature up to high temperatures, the sample recovery rate is preferably small.

The temperature measurement method described in the present embodiment may be implemented by providing a region into which high-concentration oxygen is introduced in a temperature evaluation sample wafer, or alternatively, a high-concentration oxygen may be applied to a product wafer. It is also possible to provide the monitoring area for the injected temperature measurement.

In the first embodiment, the oxygen concentration is set to a critical value of 3.2 × 10 ¹⁹ atoms · cm ⁻³ or more. However, oxygen having a concentration lower than the critical value is introduced into the entire amorphous region. Then, the temperature may be measured. As can be seen from the data in FIG. 3, in the samples in which the amount of oxygen introduced is changed variously, after the recovery in the initial flash annealing is completed, the amorphous region recovers at a recovery rate specific to each annealing temperature. For a sample containing oxygen at a concentration lower than the critical value, a straight line deviating to the right from the straight line Ko shown in FIG. 8 is obtained as a straight line representing the relationship between the annealing temperature and the recovery rate. As can be seen from FIG. 8, the smaller the recovery rate, the higher the accuracy of the temperature measurement. However, if the recovery rate is too low, a problem such as a long measurement time occurs. Further, when an in-line measurement is performed with a monitor region into which oxygen is implanted formed on a wafer, it is necessary to consider a temperature and an annealing time suitable for the process. Therefore, there is an advantage that the most advantageous recovery rate can be selected by variously changing the oxygen concentration.

In the first embodiment, in order to form an amorphous region having an oxygen concentration of 3.2 × 10 ¹⁹ atoms · cm ⁻³ or more, knock-on implantation of oxygen with As ions and ion implantation of oxygen are performed. Is used, but this is not necessarily the case, and only oxygen ion implantation may be used. In that case, for example, using a clustered manufacturing apparatus, after removing a natural oxide film by heat treatment in a vacuum in one chamber in the apparatus, for example, knock-on is performed by implanting oxygen ions in another chamber. Since a state without oxygen can be realized, there is an advantage that the concentration of oxygen can be controlled more reliably.

(Second Embodiment) Next, a temperature distribution measuring method according to a second embodiment will be described. here,
Basically, the temperature distribution inside the thermal CVD apparatus is measured by using the method in the first embodiment.

First, the relationship between the recovery rate and the annealing temperature represented by a straight line as shown in FIG. 8 is determined in advance for various ion implantation conditions. For example, the straight lines Ko and the like shown in FIG. 8 are obtained by the procedure of steps ST21 and ST22 in FIG. 7, and then the oxygen is measured under the same conditions at a plurality of locations where the actual temperature of the temperature evaluation sample wafer is to be measured. To make a sample wafer. At this time, the sample wafer is prepared by performing the steps shown in FIGS. 4A to 4C for a plurality of measurement sites. In other words, a sample in which oxygen is implanted by a knock-on effect and an amorphous region containing oxygen having a critical value (3.2 × 10 ¹⁹ atoms · cm ⁻³ ) or more is obtained by two implantation steps of oxygen ion implantation. Prepare a wafer. Thermal CVD using this sample wafer
The temperature during use in the apparatus is measured as follows.

This sample wafer is set in a place where a product wafer is actually installed, for example, in a thermal CVD apparatus for depositing a silicon oxide film. Then, in this thermal CVD apparatus, the sample wafer is held for a predetermined time t (min) under the same temperature condition as that for depositing the silicon oxide film. The recovery rate (L / t) can be calculated from the thickness L nm at which the amorphous region in the sample wafer is recrystallized during the elapse of the predetermined time t (min). Then, when the recovery rate (L / t) of each part in the sample wafer is applied to the straight line Ko in FIG. 8 for the sample wafer, the accurate temperature, that is, the temperature distribution of each part in the thermal CVD apparatus can be measured. . The data of this temperature distribution is created as the data as shown in FIG. 23 in PCT / JP98 / 02567. Further, by measuring the temperature distribution in the wafer, it is possible to grasp the relationship between the yield of silicon chips cut from each part of the wafer and the CVD temperature.

Needless to say, it is possible to measure only the temperature of a certain representative portion inside the thermal CVD apparatus or the like. In this case, even if the set temperature displayed on the temperature control unit attached to the thermal CVD apparatus is T0, if the actual temperature is T, this temperature difference ΔT (= T−T0) indicates This is a device error. Therefore, the actual C
In the VD process, the error can be corrected and the process can be managed.

Further, by installing this sample at an arbitrary position in various apparatuses such as a thermal CVD apparatus, for example, a gas introduction section and an exhaust section other than the wafer installation section, the temperature at a desired position inside the apparatus can be improved. Can be measured accurately.

In the present embodiment, the ion implantation of As is used for forming the amorphous region, but ion implantation of silicon or phosphorus may be used instead of As.

(Third Embodiment) Next, a description will be given of a third embodiment relating to an evaluation sample in which the range in which the temperature can be measured is expanded by providing regions in the wafer in which the recovery rate is variously adjusted.

FIG. 9 is a diagram showing data comparing the recovery rates when only arsenic (As) is injected and when arsenic (As) and boron (B) are injected. The horizontal axis in the figure represents the measurement location (49 points) in the wafer, and the vertical axis represents the recovery rate of the amorphous region. Arsenic (As) was used as a sample wafer at an accelerating voltage of 3
An amorphous region was formed by implanting under the conditions of 0 keV and a dose of 3 × 10 ¹⁴ atoms · cm ⁻² (data indicated by △ in the figure), and arsenic (As) was accelerated at 30 keV and a dose of 3 × 10 ^14. After implanting under the condition of atoms · cm ⁻² to form an amorphous region, boron (B) is further injected into the amorphous region at an acceleration voltage of 8 keV and a dose of 3 ×.
A recovery rate is measured by preparing a material implanted under the condition of 10 ¹⁵ atoms · cm ⁻² (data indicated by a circle in the figure). No oxygen ion implantation was performed. From this data, the following can be seen.

As shown in the figure, comparing the average values at the respective measurement points, the amorphous region implanted with arsenic (As) alone is better than the amorphous region implanted with arsenic (As) and boron (B). Recovery rate is smaller than that. Therefore, it is understood that the adjustment of the recovery rate can be performed not only by adjusting the concentration of oxygen ion implantation as in the first embodiment but also by changing and combining ion species. Adjusting the recovery rate means that the range in which reliable temperature measurement can be performed under realistic conditions can be adjusted.Therefore, the temperature measurement range can be increased by variously combining such implanted ion species. It can be adjusted appropriately.

FIG. 10 is a diagram showing a difference in the recovery rate between the amorphous region formed by Ge implantation and the amorphous region formed by As implantation. The implantation conditions were as follows: an acceleration voltage of 30 keV and a dose of 3
× 10 ¹⁴ atoms · cm ⁻² . The annealing temperature is 550 ° C. As shown in the figure, since the recovery rate of Ge is smaller than the recovery rate of As, the amorphous region formed by the implantation of Ge is used for measuring a temperature higher than that of the amorphous region formed by the implantation of As. Can be provided.

FIGS. 11A and 11B are plan views showing two methods for forming an evaluation sample wafer having four amorphous regions having different recovery rates from each other. In the case of one method, as shown in FIG. 11A, n temperature measurement regions R1, R2,.
n are provided, and each temperature measurement region R1, R2,
, Rn are the first amorphous regions R11, R21,..., Rn1 into which arsenic (As) and boron (B) corresponding to the data indicated by the circle in FIG. the second amorphous region R12 injected only arsenic (as) corresponding to the data, R22, ..., and Rn2, dose 1 × 10 ¹⁵ atoms were germanium (Ge) description 10 &
third amorphous region R13, R23 injected in cm ^-2,
, Rn3 and the arsenic (A) described in the first embodiment.
s) and the fourth injected oxygen (0) at a concentration higher than the critical value.
Amorphous regions R14, R24,..., Rn4 are provided. According to another method, as shown in FIG. 11B, the wafer is divided into four parts, and the first part in which arsenic (As) and boron (B) corresponding to the data indicated by the circles shown in FIG. 9 are implanted.
The amorphous region Ra, the second amorphous region Rb in which only arsenic (As) corresponding to the data indicated by the mark Δ shown in FIG. 9 is implanted, and the germanium (G) described in FIG.
e) at a dose of 1 × 10 ¹⁵ atoms · cm ⁻² , the third amorphous region Rc, arsenic (As) described in the first embodiment, and oxygen (0) having a concentration equal to or higher than the critical value.
And a fourth amorphous region Rd into which is implanted.

FIG. 12 is a diagram showing a temperature measurable range of each amorphous region when the evaluation sample wafer shown in FIG. 11A or 11B is used. When the recovery rate is low, the appropriate temperature measurement range shifts to the high temperature side, and when the recovery rate is high, the appropriate temperature measurement range shifts to the low temperature side.
In the case of this example, the realistic temperature measurement range in which the reliability can be ensured is 420 ° C. or more in the first amorphous region R1.
5 ° C. or lower, and 480 in the second amorphous region R2.
C. or higher and 580 ° C. or lower and the third amorphous region R3
Is 540 ° C. or more and 625 ° C. or less, and is 575 ° C. or more and 650 ° C. or less in the fourth amorphous region R4. Thus, by providing the first to fourth amorphous regions having four types of temperature measurement ranges on one evaluation sample wafer, it is possible to measure the temperature in the range from 420 ° C. to 650 ° C.

When the sample wafer shown in FIG. 11A is used, a large number of temperature measurement regions R1, R2,..., Rn each having first to fourth amorphous regions are provided on the wafer. Accordingly, the in-plane temperature distribution of the wafer can be measured in a wide temperature range.

In the case where the sample wafer shown in FIG. 11B is used, when the temperature in a certain process is unknown, the rough temperature is first grasped, and then the temperature is measured again to obtain an accurate temperature distribution. Can be grasped. For example, first, it is assumed that only the first amorphous region Ra has been recovered as a result of temperature measurement using this sample wafer. At this time, since it can be understood from FIG. 12 that the temperature range is 425 ° C. or more and 520 ° C. or less, a sample wafer having the entire surface of the wafer as the first amorphous region Ra is prepared, and temperature measurement is performed using this sample wafer. As a result, accurate measurement of the temperature distribution becomes possible.

(Fourth Embodiment) Next, a fourth embodiment relating to ion implantation at a low temperature will be described. FIG.
3 (a) to 3 (d) show that the substrate temperature is 0 ° C.,
Arsenic (As) at -10 ° C, -20 ° C and -30 ° C
FIG. 4 is a cross-sectional view showing a shape of an interface between an amorphous region and a crystal region formed by the implantation of GaN. Arsenic (As) was implanted under the conditions of an acceleration voltage of 30 keV and a dose of 3.
It is 0 × 10 ¹⁴ atoms · cm ⁻² . However, the substrate temperature in this embodiment is not obtained by directly measuring the substrate temperature by the method of the present invention, but is the temperature of a platen for mounting a wafer. Therefore, the temperature at the upper surface of the wafer is likely to be several degrees lower than this temperature.

As can be seen from FIGS. 13 (a) to 13 (d),
Although there are some variations, FIGS. 13A and 13B
In the case of implantation at a substrate temperature of 0 ° C. and −10 ° C., the interface between the two does not clearly appear, and the unevenness of the portion that appears to be the interface is large. In other words, it is considered that the boundary between the amorphous region and the crystalline region is not clear, and the two are in a state of being disturbed near the boundary. On the other hand, in the case of implantation at a substrate temperature of −20 ° C. or −30 ° C., the unevenness of the interface is reduced and the interface is clearly shown.

In the case of the injection at around room temperature,
As in the case of implantation at a substrate temperature of 0 ° C., the boundary between the amorphous region and the crystalline region does not clearly appear, and the portion that appears to be the interface has large irregularities.

FIG. 14 is a diagram showing a recovery rate of an amorphous region formed by ion implantation at a low temperature. In the figure, the horizontal axis represents the annealing time, and the vertical axis represents the thickness of the amorphous region. All the data shown in the figure show that arsenic (As) is accelerated at an acceleration voltage of 30 ke.
V is implanted under the conditions of a dose of 3.0 × 10 ¹⁴ atoms · cm ⁻² . □ indicates data of the amorphous region formed by ion implantation at room temperature.
The circles indicate data of amorphous regions formed by ion implantation at a low temperature of −40 ° C., respectively. As shown in the figure, the recovery rate of the amorphous region formed by the ion implantation at room temperature shows that the annealing time elapses to some extent (here, about 10 s).
ec) It becomes constant, but since the initial thickness deviates from the straight line and is considerably higher, it is considered that the recovery rate is faster in a region corresponding to the first flash annealing. On the other hand, the recovery rate of the amorphous region formed by ion implantation at a substrate temperature of −40 ° C.
It is almost constant from the beginning. This difference may be due to the following reasons.

In the case of the amorphous region formed by ion implantation at room temperature, the boundary between the amorphous region and the crystal region is unclear and the unevenness of the interface is similar to that at the substrate temperature of 0 ° C. shown in FIG. Because of its large size, it seems that the thickness of the amorphous region apparently decreases promptly at the beginning of annealing. In particular,
The reason why the data of the initial thickness is measured to be larger than the value of the point on the straight line may be that the thickness of the amorphous region is measured in a form that also incorporates a region that is partially crystalline. Then, from the time when the recrystallization proceeds to some extent, the boundary between the two becomes clear, and the unevenness of the interface becomes smaller (after about 10 sec in FIG. 14), the diameter decreases at a constant gentle speed.

On the other hand, in the case of an amorphous region formed by ion implantation at a low temperature, FIG.
Since the boundary between the amorphous region and the crystalline region is clear and the unevenness of the interface is small as in the case of the substrate temperature of −30 ° C., it is considered that a substantially constant recovery rate can be obtained from the beginning of annealing. The recovery rate itself is
In each case, it is about 21 (nm / min), which indicates that the recovery rate itself is uniquely determined depending on the concentration of arsenic (As).

FIG. 15 is a view showing a part of the spectrum of cos Δ obtained by spectroscopic ellipsometry measurements on the amorphous regions formed under the implantation conditions shown in FIGS. 13 (a) to 13 (d). . In the figure, the horizontal axis represents the wavelength of the measurement light, and the vertical axis represents the value of cos Δ. As shown in the figure, a spectral ellipsometry spectrum from an amorphous region ion-implanted at a substrate temperature of 0 ° C. and −10 ° C. and a spectral ellipsometric spectrum from an amorphous region ion-implanted at a substrate temperature of −20 ° C. and −30 ° C. It is clearly separated from the measurement spectrum, and it is presumed that there is a clear structural difference between the two groups.

13 (a) to 13 (d), FIG. 14 and FIG. 15 show that by performing ion implantation under a low temperature condition that the substrate temperature is lower than −10 ° C., the amorphous region—the crystalline region The boundary can be made clear and the unevenness of the interface can be reduced, and the following effects can be obtained.

As a first effect, the accuracy and reliability of temperature measurement are improved. It is for the following two reasons. First, to measure the temperature, it is necessary to calculate the recovery rate of the amorphous region by annealing, and to calculate the recovery rate, it is necessary to measure the thickness of the amorphous region by ellipsometry or the like. At the time of the thickness measurement, for example, a difference in thickness at 49 points (not points for measuring the temperature distribution) as shown in FIG. 9 is reduced. Then, since the thickness of the measured amorphous region becomes almost constant with good reproducibility, the value of the recovery rate at each point, that is, the temperature value becomes uniform. Therefore,
By clearly defining the boundary between the two or reducing the unevenness of the interface, the dispersion of the measured values is reduced, and the accuracy and reliability of the measurement of the temperature and the temperature distribution are improved.

Further, as discussed with reference to the experimental results in FIG. 14, when the boundary between the two is not clear and the unevenness of the interface is large, the initial recovery rate is fast until the boundary becomes clear or the unevenness of the interface becomes small. It is also considered that the variation is large. This is suggested by various experimental results. If the boundary between the amorphous region and the crystalline region is not clear at the time of ion implantation and the unevenness of the interface is large, it is necessary to exclude data immediately after the start of annealing when calculating the recovery rate. However, the actual annealing is often performed by short-time annealing such as RTA or flash annealing (also called spike annealing). Therefore, especially when temperature measurement is performed in-line, the initial recovery rate is important. Therefore, by forming the boundary between them clearly or reducing the unevenness of the interface, the recovery rate becomes stable and almost constant even at the beginning of annealing, resulting in improved accuracy and reliability of the measured temperature value. I do.

As a second effect, the utility value as pre-amorphous implantation in the manufacturing process of a device to be actually used is increased. Pre-amorphous implantation refers to ion implantation performed to disturb the crystallinity of the source / drain regions to form an amorphous structure (to promote silicidation) before the salicide process, or to ion implantation of low-concentration boron. Refers to ion implantation performed to prevent channeling. The above-described effect of improving the temperature measurement accuracy by improving the flatness of the interface can be realized by other means. However, the following effects are obtained separately from the improvement of the temperature measurement accuracy by ion implantation at a low temperature.

For example, as described above, by increasing the oxygen concentration in the amorphous region above the critical value, the relationship between the annealing temperature and the recovery rate becomes one straight line as a whole (see FIG. 6), and is shown in FIG. Such a relational expression between the recovery rate and the temperature can be established. However, although increasing the oxygen concentration in the amorphous region has no adverse effect on the wafer for temperature evaluation, it has the adverse effect of causing an oxygen-induced defect (OSF) on an actually used device and deteriorating the operating characteristics of the device. Exert.
Therefore, it is not appropriate to implant oxygen ions at a high concentration as a pre-amorphous implantation in an actual device.

On the other hand, as will be described later,
A relatively high dose (eg, 4 × 10 ^Fifteenatoms · cm^-2About
Formed by ion implantation
The boundary between the amorphous and crystalline regions
be able to. But in general, try to silicide
The surface of the region (source / drain region)
High concentration of arsenic ions etc.
When this occurs, oxygen is also injected into the area by knock-on.
(See FIG. 2). As a result, the generation of oxygen-induced defects
It is difficult to suppress the

On the other hand, when ion implantation at a low temperature is used, as shown in FIG. 14, the dose amount is 3 × 10 ¹⁴ at.
Only by implanting arsenic ions or the like at a concentration about one order of magnitude lower than oms · cm ⁻² , the boundary between the amorphous region and the crystal region can be clearly defined or the unevenness of the interface can be reduced. When an element heavier than oxygen is implanted, if the implantation amount is reduced by one order of magnitude, the concentration of oxygen implanted by knock-on is also about 1%.
Orders of magnitude less. As can be seen from the oxygen concentration profile shown in FIG. 2 in the first embodiment, when the oxygen concentration due to knock-on is reduced to about 1/10, the oxygen concentration in the amorphous region is originally contained in the silicon substrate. The oxygen concentration is almost the same as the oxygen concentration (about 2.0 × 10 ¹⁸ atoms cm ⁻³ ). Therefore, in this case, even if a natural oxide film is present on the region to be silicided, the amount of intrusion of oxygen due to knock-on can be reduced, so that generation of oxygen-induced defects can be reliably suppressed. Therefore, by performing ion implantation of arsenic or the like at a low temperature as pre-amorphous implantation, which is a pretreatment of the salicide process, when performing temperature measurement in-line, it is possible to suppress the occurrence of oxygen-induced defects and to improve the accuracy and Reliability can be improved.

As a third effect, by employing ion implantation at a low temperature as pre-amorphous implantation,
As a result of making the boundary between the amorphous region and the crystal region clear or reducing the unevenness of the interface, a flat silicide layer can be formed later. Therefore, the effect of suppressing junction leakage occurring at the PN junction below the interface in the diffusion layer having the salicide structure can be obtained.

As a fourth effect, when used as pre-amorphous implantation for preventing channeling, a shallow diffusion layer can be formed with good reproducibility. When annealing for activation is performed after implanting boron or the like, it is known that the diffusion speed of boron or the like increases near the disordered structure near the boundary between the amorphous region and the crystalline region. If the boundary between the two is unclear and the unevenness of the interface is large,
This means that the range in which the structure is disordered is wide, and in that case, the diffusion layer is widened and the variation between lots is large. On the other hand, by using low-temperature ion implantation as pre-amorphous implantation, the boundary between the two can be clarified or the unevenness of the interface can be reduced, so that the diffusion layer by activation after ion implantation of boron or the like is made shallow. It can be formed with good reproducibility.

In this embodiment, an example in which As is implanted as an ion species has been described. However, even if Ge is implanted instead of As, the same effect can be obtained with the same dose. Ge is because Ge has an atomic number (32) close to arsenic (33), and Ge that is actually implanted is Ge isotope Ge ³³ having almost the same mass as arsenic. Further, ion implantation of a group IV element having a mass larger than Ge can be used.

(Fifth Embodiment) Next, a fifth embodiment relating to ion implantation of a group IV element such as Ge will be described. Group IV elements refer to elements such as C, Si, Ge, Sn, and Pb.

FIG. 16 shows a boundary between an amorphous region formed by injecting Ge as a group IV element at an acceleration voltage of 30 keV and a dose of 4 × 10 ¹⁵ atoms · cm ⁻² into a silicon substrate, and a crystal region below the amorphous region. 9 is a TEM photograph showing a structure in the vicinity. As shown in the figure, the boundary between the amorphous region and the crystalline region formed by Ge ion implantation is clear, and the unevenness at the interface is also small. It has been confirmed that this effect can be surely obtained when the dose is 1 × 10 ¹⁵ atoms · cm ⁻² or more in the case of Ge ion implantation at room temperature.

Therefore, also in the present embodiment, the first to fourth effects described in the fourth embodiment can be exhibited. In addition, Ge is an IV element and has a neutral conductivity as a type even when implanted into silicon, that is, whether implanted into an N-type diffusion layer or a P-type diffusion layer,
It does not affect the operation of the device. Therefore, it can be used as a pre-amorphous implantation in a manufacturing process of an actually used CMOS device.

Note that the ion species is not limited to Ge, and elements such as C, Si, Sn, and Pb can be used. In the case of an element having a small mass, the boundary with the crystal region is clear unless the dose is increased. It becomes difficult to form a suitable amorphous region. Therefore, it is preferable to use Ge or a group IV element having a larger mass than Ge.

Instead of using a group IV element, arsenic (A
s), phosphorus (P), a halogen element, an inert gas element or the like can be used to achieve the same effect. In this case, there is an advantage that it is not necessary to use the ion species GeF ₄ which is a corrosive gas required when Ge is used.

(Sixth Embodiment) Next, a sixth embodiment relating to low-temperature annealing after ion implantation will be described.

As described in the fourth embodiment, the boundary between the amorphous region and the crystalline region formed by low-concentration ion implantation does not clearly appear. 450 ° C. or lower), the boundary between the two can be clarified or the unevenness of the interface can be reduced.

In the present embodiment, although the boundary that does not clearly appear at first becomes gradually clear, the recovery proceeds until the boundary between the amorphous region and the crystalline region becomes clear or the unevenness of the interface becomes small. No further recovery was confirmed. Accordingly, by preparing a wafer for which the boundary between the amorphous region and the crystalline region is clearly defined or the unevenness of the interface is reduced as a wafer for temperature identification, the relationship between the annealing temperature and the recovery amount is substantially reduced from the beginning. Since it can be one straight line,
The accuracy of temperature measurement can be improved.

Further, by performing a silicidation process using the amorphous region formed according to the present embodiment, a planarized silicide layer can be formed.

(Seventh Embodiment) Next, a seventh embodiment relating to a silicidation process using each of the above embodiments will be described.

In this embodiment, first, using any one of the above embodiments, a wafer having a semiconductor region in which the boundary between the amorphous region and the crystalline region is clarified and the unevenness of the interface between them is small is used. Form. Then, a refractory metal film (for example, a titanium film, a cobalt film, a nickel film, etc.) is deposited on the substrate. Then, laser annealing is performed by irradiating a laser to the upper surface of the substrate. At this time, the reaction between the refractory metal film and the amorphous region proceeds, and a silicide layer is formed.

FIG. 17 is a diagram showing the reflectance spectrum of the titanium silicide layer formed on the N-type and P-type diffusion layers of the wafer formed in this embodiment. Here, this titanium silicide layer is formed by performing laser annealing at a temperature of 450 ° C. or less. In the figure,
The horizontal axis represents the wavelength (nm) of the measurement light, and the vertical axis represents the reflectance. PD indicates a high-concentration P-type diffusion layer (source / drain region), and ND indicates a high-concentration N-type diffusion layer. As shown in the figure, since the reflectances from both are almost the same over a wide range, it is estimated that the flatness of the titanium silicide layer is good.

Therefore, in this embodiment, silicidation is performed using a wafer having a semiconductor region in which the boundary between the amorphous region and the crystalline region is clear and the unevenness of the interface is small. Here, when silicidation is performed by laser annealing, only the amorphous region having a low melting point is melted, but the crystal region thereunder is not melted.
Therefore, only the amorphous region can be surely selectively silicided, and a silicide layer with good flatness can be formed. The good flatness of the silicide layer makes it possible to suppress the occurrence of agglomeration and to suppress the junction leak.

(Other Embodiments) When temperature measurement is performed using the ion implantation of any of the above embodiments, ion implantation is performed from both sides of the wafer to form an amorphous region not only on the upper surface but also on the back surface of the wafer. By forming, two temperature measurements can be performed with one sample. In the case where the annealing step is performed by irradiating the upper surface of the wafer with a laser, only the amorphous region on the upper surface side is recovered, and annealing is performed under the condition that the amorphous region on the lower surface side is not recovered. Can be measured. However, since the amorphous region on the back side has not yet been recovered, the temperature can be obtained by performing annealing in another temperature range (particularly, a high temperature range). When the diameter of the wafer is large and the thickness of the wafer is large, the temperature of the amorphous region on the rear surface side may be considerably lower than the temperature of the amorphous region on the upper surface side. In such a case, even if the amorphous region on the upper surface side and the amorphous region on the lower surface side are formed under the same ion implantation conditions and the same ion species, only the amorphous region on the upper surface side is recovered, and the amorphous region on the rear surface side is recovered. It is quite possible that the area has not recovered. Therefore, it is also possible to first perform temperature measurement by laser annealing, turn over the wafer in which the amorphous region on the upper surface has been restored, irradiate the laser to the rear surface facing upward, perform annealing, and perform the next temperature measurement. Good.

When temperature measurement is performed using the ion implantation of any of the above embodiments, ion implantation is performed from both sides of the wafer, and an amorphous region is formed not only on the upper surface but also on the back surface of the wafer. Can be determined. In other words, when the annealing step is performed by irradiating the upper surface of the wafer with a laser, the recovery rate between the amorphous region on the upper surface side and the amorphous region on the rear surface side is determined, and the temperature between the region near the upper surface and the region near the rear surface is determined. The difference can be detected. Therefore, for example, when flash annealing is performed, the thermal conductivity of the wafer can be determined from the temperature difference and the time change of the temperature change. Thereby, it becomes possible to strictly control the temperature in various processes. In particular, as the diameter of the wafer increases, the thickness of the wafer also increases. At that time, the relationship between the thickness of the wafer and the temperature difference between the upper surface and the lower surface can be grasped.
It is possible to improve the manufacturing yield and manufacture a high-quality semiconductor device.

The temperature measurement method of each of the above embodiments may be performed using a sample wafer for temperature measurement, may be performed by providing a monitor area in the wafer, or may be used to actually form a product device. May be performed using a wafer for this purpose.

Further, the temperature measuring method in each of the above embodiments is stored in a recording medium utilizing magnetic, optical, and electrical characteristics, and is used in a semiconductor device manufacturing process using this recording medium. Can be.

[0108]

According to the present invention, a temperature measuring method capable of accurately measuring the actual temperature and temperature distribution inside an apparatus, a temperature measurement sample capable of providing accurate temperature and temperature distribution measurement, The formation of a shallow diffusion layer and a silicide layer with good flatness can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a time change of a thickness of an amorphous region, that is, a recovery rate when the amorphous region is annealed at 550 ° C.

FIG. 2. Arsenic (A) on as-implanted silicon substrate
FIG. 3 is a diagram showing concentration profiles of s) and oxygen (O) in a substrate depth direction.

FIG. 3 is a diagram showing a result of measuring a recovery rate by changing an oxygen injection amount into an amorphous region into a plurality of types.

FIGS. 4A to 4D are cross-sectional views illustrating a procedure of an annealing process for temperature measurement according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating a procedure of annealing and temperature measurement according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a recovery rate of an amorphous region to a crystal in the first embodiment.

FIG. 7 is a flowchart illustrating a procedure for determining a temperature from a relationship between an annealing temperature and a recovery rate in the first embodiment.

FIG. 8 is a diagram showing the relationship between the recovery rate and the annealing temperature T in a silicon substrate into which high-concentration oxygen is introduced, in addition to the data indicating the relationship between the recovery rate and the annealing temperature T described in the literature. is there.

FIG. 9 is a diagram showing data comparing the recovery rates when only As is injected and when As and B are injected according to the third embodiment of the present invention.

FIG. 10 is a diagram showing a difference in a recovery rate between an amorphous region formed by Ge implantation and an amorphous region formed by As implantation in the third embodiment.

FIGS. 11A and 11B are plan views showing two methods for forming an evaluation sample wafer having four amorphous regions having different recovery rates according to the third embodiment.

12 is a diagram showing a temperature measurable range of each amorphous region when the evaluation sample wafer shown in FIG. 11 is used.

FIGS. 13A to 13D respectively show arsenic (A) at substrate temperatures of 0 ° C., −10 ° C., −20 ° C., and −30 ° C., respectively.
It is sectional drawing which shows the shape of the interface between the amorphous region and the crystalline region formed by injection | pouring of s).

FIG. 14 is a diagram showing a recovery rate of an amorphous region formed by ion implantation at a low temperature.

FIG. 15 is a diagram showing a part of a cos Δ spectrum obtained by spectroscopic ellipsometry measurement on amorphous regions formed under the implantation conditions shown in FIGS. 13 (a) to 13 (d).

FIG. 16 shows Ge as a group IV element in the fifth embodiment.
FIG. 4 is a TEM photograph showing a structure near a boundary between an amorphous region formed by implanting a crystal and a crystal region below the amorphous region.

FIG. 17 shows the N of the wafer formed in the seventh embodiment.
FIG. 4 is a diagram showing a reflectance spectrum of a titanium silicide layer formed on a p-type and p-type diffusion layers.

[Explanation of symbols]

 Reference Signs List 10 silicon substrate (crystal) 10a amorphous region 10b crystal region 11 silicon oxide film 10aa high concentration oxygen region 10bb low concentration oxygen region

Continuation of the front page (56) References JP-A-5-249031 (JP, A) JP-A-6-77301 (JP, A) JP-A-5-121509 (JP, A) JP-A-6-244255 (JP) , A) JP-A-9-82767 (JP, A) WO 98/57146 (WO, A1) Sameshima and S.M. J. Isui, Pulsed laser-induced amorphism asion of silicone films, J. Am. Appl. Phys. , USA, August 1, 1991, 70 (3), p. p. 1281-1289 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/66 G01K 11/00 H01L 21/205 H01L 21/302

Claims (16)

(57) [Claims] 1. A step (a) of doping oxygen into an amorphous region formed in a semiconductor region of a substrate, and a step of heating the amorphous region for a predetermined time to obtain a recovery rate at which the amorphous region is recrystallized ( b)
And (c) obtaining the temperature of the amorphous region in the step (b) based on the relationship between the heating rate and the recovery rate of the amorphous region prepared in advance.
And a temperature measuring method. 2. The temperature measuring method according to claim 1, wherein in the step (a), oxygen is supplied so that the recovery rate in the step (b) reaches a critical value for making the recovery rate substantially constant from the start of heating. A temperature measuring method characterized by doping. 3. The temperature measuring method according to claim 2, wherein the critical value is 3.2 × 10 ¹⁹ atoms · cm ⁻³ . 4. The temperature measuring method according to claim 1, wherein an oxide film is formed on the semiconductor region of the substrate before performing the step (a). A temperature measuring method, further comprising a step of forming the amorphous region by implanting impurities into the semiconductor region before the step (a). 5. The temperature measuring method according to claim 1, wherein a natural oxide film on the semiconductor region is removed under reduced pressure before the step (a). A temperature measuring method, wherein the step (a) is performed after the step of removing the natural oxide film, while maintaining the substrate under reduced pressure without exposing the substrate to the atmosphere. 6. The temperature measuring method according to claim 1, wherein the step (b) is performed by using a thickness measurement of an amorphous region by spectroscopic ellipsometry. Temperature measurement method. 7. A step (a) of forming an amorphous region by ion implantation of a group IV element into a semiconductor region of a substrate, and a recovery rate at which the amorphous region is recrystallized by heating the amorphous region for a predetermined time. (B)
And (c) obtaining the temperature of the amorphous region in the step (b) based on the relationship between the heating rate and the recovery rate of the amorphous region prepared in advance.
And a temperature measuring method. 8. The temperature measuring method according to claim 7, wherein in the step (a), the dose is 1 × 10 ¹⁵ atoms.
-A temperature measuring method characterized by performing Ge ion implantation under the condition of cm ^-2 or more. 9. Arsenic (As), in a semiconductor region of a substrate,
(A) forming an amorphous region by performing ion implantation of at least one of phosphorus (P), a halogen element, and an inert gas element; and heating the amorphous region for a predetermined time to recrystallize the amorphous region. (B) for determining the recovery rate to be changed
And (c) obtaining the temperature of the amorphous region in the step (b) based on the relationship between the heating rate and the recovery rate of the amorphous region prepared in advance.
And a temperature measuring method. 10. A step (a) of forming a plurality of amorphous regions by ion-implanting a plurality of portions of a semiconductor region of a substrate under different conditions, and heating the plurality of amorphous regions for a predetermined time to form each amorphous region. (B) individually obtaining a recovery rate at which the region is recrystallized, and the step (b) corresponding to each of the recovery rates based on a relationship between the previously prepared recovery rate of each of the amorphous regions and the heating temperature. (c) obtaining a temperature of each amorphous region in (b). 11. The temperature measurement method according to claim 10, wherein in the step (a), ion species or ion implantation conditions to be implanted into the plurality of locations are made different. 12. The temperature measuring method according to claim 10 or 11, wherein the substrate is in a wafer state, and the step (a) is to divide the wafer into four parts vertically and horizontally when the four parts are viewed in a plane. A temperature measuring method, which is performed using a sample that is a partitioned area. 13. A step (a) of implanting ions into a first semiconductor region on an upper surface of a substrate to form a first amorphous region, and adding the ions to a second semiconductor region on a rear surface of the substrate. (B) implanting to form a second amorphous region; and heating the substrate under conditions that restore the first amorphous region and do not restore the second amorphous region. (C) obtaining the recovery rate of the amorphous region of the first amorphous region; and, based on the relationship between the previously prepared recovery rate of the first amorphous region and the heating temperature, (D) obtaining one of the temperatures. 14. A step (a) of performing ion implantation into a first semiconductor region on an upper surface of a substrate to form a first amorphous region, and applying the ion to a second semiconductor region on a rear surface of the substrate. (B) implanting to form a second amorphous region; and heating the substrate to recover the first and second amorphous regions and recover the first and second amorphous regions. Steps (c) for calculating the rates, and steps (c) corresponding to the respective recovery rates, based on the relationship between the recovery rates of the first and second amorphous regions and the heating temperature prepared in advance. First
And (e) obtaining a temperature of the substrate from a temperature difference between the first and second amorphous regions. (E) obtaining a temperature of the substrate from the temperature difference between the first and second amorphous regions. 15. The method according to claim 15, wherein the substrate temperature is within a semiconductor region of the substrate.
(A) forming an amorphous region by performing ion implantation under a condition lower than 10 ° C., and (b) obtaining a recovery rate at which the amorphous region is recrystallized by heating the amorphous region for a certain period of time.
And (c) obtaining the temperature of the amorphous region in the step (b) based on the relationship between the heating rate and the recovery rate of the amorphous region prepared in advance.
And a temperature measuring method. 16. A step of forming an amorphous region in a semiconductor region of a substrate by performing ion implantation.
(B) annealing the amorphous region at a temperature in the range of 300 ° C. to 450 ° C .; and (c) heating the amorphous region to determine a recovery rate at which the amorphous region is recrystallized. (D) determining the temperature of the amorphous region in the step (c) based on the relationship between the heating rate and the recovery rate of the amorphous region prepared in advance.
And a temperature measuring method.