JP3272706B2 - How to make a sample for temperature measurement - Google Patents

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]

According to a first method for preparing a sample for temperature measurement of the present invention, a recovery rate at which an amorphous region of a substrate is recrystallized by heating the amorphous region for a predetermined time is determined. A method for preparing a temperature measurement sample for measuring the temperature of the amorphous region during the heating based on the relationship between the recovery rate of the amorphous region and the heating temperature, wherein the sample is formed in the semiconductor region of the substrate. In this method, oxygen is doped into the amorphous region at a critical concentration so that the recovery rate during heating is substantially constant from the start of heating.

According to this method, it is possible to prepare a sample capable of performing highly accurate and reliable temperature measurement using the stable recovery rate of the amorphous region.

In the case where an oxide film is formed on the semiconductor region of the substrate before doping with the oxygen, before the doping with the oxygen, ions of impurities are formed on the semiconductor region from above the oxide film. By performing the implantation, the above-mentioned amorphous region can be formed.

According to this method, it is possible to prepare a sample capable of measuring the temperature while eliminating the adverse effect of oxygen that has been knocked on and has entered the amorphous region.

Before doping the oxygen, the natural oxide film on the semiconductor region is removed under reduced pressure, and then the semiconductor region is doped by ion implantation of oxygen.
A temperature specifying sample in which the oxygen concentration is more accurately adjusted can be obtained.

According to a second method for preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region at the time of the heating based on a relationship between a rate and a heating temperature, wherein ion implantation of a group IV element is performed in a semiconductor region of a substrate. This is a method of forming an amorphous region by forming a row.

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

At the time of the above ion implantation, the dose amount is 1 × 1
By performing Ge ion implantation under the condition of 0 ¹⁵ atoms · cm ⁻² or more, the boundary between the amorphous region and the crystal region in the semiconductor region can be clarified, or the unevenness of the interface can be reduced, and accuracy and reliability can be reduced. A sample capable of performing high temperature measurement can be prepared.

According to a third method of preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for preparing a temperature measurement sample for measuring a temperature of an amorphous region at the time of the heating based on a relationship between a rate and a heating temperature, wherein arsenic (As), phosphorus ( This is a method of forming an amorphous region by performing ion implantation of at least one of P), a halogen element, and an inert gas element.

According to this method, the same effect as that of the second method for preparing a temperature measurement sample can be exhibited.

According to a fourth method of preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for creating a temperature measurement sample for measuring the temperature of the amorphous region during the heating based on the relationship between the rate and the heating temperature, wherein a plurality of locations in the semiconductor region of the substrate are provided under different conditions. This is a method of forming a plurality of amorphous regions by performing ion implantation.

According to this method, a sample capable of measuring a temperature in a wide temperature range as described above can be prepared.

At the time of the above-mentioned ion implantation, it is preferable to make ion species to be implanted into the plurality of locations different.

Further, the above-mentioned substrate is assumed to be in a wafer state, and the above-mentioned four portions are viewed from above, and
It can be a divided area.

According to a fifth method for preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a predetermined time is determined. A method for preparing a temperature measurement sample for measuring a temperature of an amorphous region at the time of heating based on a relationship between a rate and a heating temperature, the method comprising: ion-implanting a first semiconductor region on an upper surface of a substrate. Forming a first amorphous region in a row, and (b) performing ion implantation into a second semiconductor region on the back surface of the substrate to form a second amorphous region.

According to this method, a sample capable of performing temperature measurement twice can be prepared by the above-described operation.

According to a sixth method for preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region during heating based on a relationship between a rate and a heating temperature, the method comprising: ion-implanting a first semiconductor region on an upper surface of a substrate; (A) to form a first amorphous region by performing
(B) forming the second amorphous region by performing the above-described ion implantation in the semiconductor region of (a), and when the temperatures of the first and second amorphous regions are obtained, the first and second amorphous regions are obtained. Is a method for forming a sample from which the thermal conductivity of the substrate can be determined from the temperature difference in the amorphous region.

According to this method, a sample which can be used for temperature control for improving the yield in the manufacturing process, which is important especially when the thickness of the wafer is increased due to the increase in the diameter of the wafer, is obtained.

According to a seventh method for preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for preparing a temperature measurement sample for measuring a temperature of an amorphous region during heating based on a relationship between a rate and a heating temperature, wherein the substrate temperature is lower than −10 ° C. in a semiconductor region of the substrate. In this method, the amorphous region is formed by performing ion implantation under low conditions.

According to this method, a state in which a clear boundary exists between the amorphous region and the crystalline region in the semiconductor region or a state in which the unevenness of the interface is small can be obtained, and a highly accurate and reliable temperature measurement can be performed. Can make a possible sample.

According to an eighth method of preparing a sample for temperature measurement of the present invention, a recovery rate at which the amorphous region is recrystallized by heating the amorphous region of the substrate for a certain period of time is determined. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region at the time of the heating based on a relationship between a rate and a heating temperature. and step (a) to form a, the amorphous region 300 ° C. or more on 450
Step (b) of annealing at a temperature in the range of not more than ℃.
And

According to this method, a state in which a clear boundary exists between the amorphous region and the crystalline region in the semiconductor region or a state in which the unevenness of the interface is small can be obtained, and a highly accurate and reliable temperature measurement can be performed. Can make a possible sample.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Principle of Temperature Measurement Using Recovery Rate of Amorphous Region
CT / JP98 / 02567 (International Publication Number WO98 /
57146), a process in which a semiconductor region (amorphous region) into which impurity ions are implanted and made amorphous by annealing is evaluated by a spectroscopic ellipsometry method, and the thickness of the amorphous region is determined in-line. Because it can be detected by inspection of destruction, and the recovery rate, which is the amount of decrease in the film thickness of the amorphous region per unit time, depends on the annealing temperature,
It has been found that the actual temperature and temperature distribution on the wafer surface (both the upper and lower surfaces of the wafer) can be detected by determining the recovery rate. 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. 3, as the oxygen concentration increases, the slope of the recovery rate by flash annealing gradually decreases, so that the portion where the recovery rate finally changes (the thickness shown in FIG. 1) (Value of 28 nm) is expected to move upward to reach the position of annealing time 0. That is, the position of the oxygen concentration of 3.2 × 10 ¹⁹ atoms · cm ^{−3 at which} the recovery rate changes needs only to be at the position of 55 nm in thickness shown in FIG. In other words, the entire area of the amorphous region has a concentration of 3.2 × 10 ¹⁹ at.
It was estimated that the recovery rate was uniform and small when oxygen was doped at oms · cm ⁻³ or more.

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 of the recovery amount of the amorphous region can be reduced, so that the accuracy of the temperature measurement is improved. Hereinafter, a first embodiment for supporting this estimation will be described.

(First Embodiment) FIGS. 4A to 4D are cross-sectional views showing a procedure of an annealing process for temperature measurement according to a first embodiment of the present invention. FIG. 5 is a flowchart showing the procedure of annealing and temperature measurement. Hereinafter, FIGS. 4 (a) to 4 (d)
The procedure of the annealing process in this embodiment will be described with reference to 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, arsenic ions (As ⁺ ) are implanted from above the silicon oxide film 11 at room temperature under the conditions of an acceleration voltage of 30 KeV and a dose of 4 × 10 ¹⁵ cm ⁻² . As a result of this ion implantation, as shown in FIG. 4B, the silicon substrate 10 has an amorphous region 10a whose crystallinity has been disturbed by arsenic ion implantation and a portion below the amorphous region 10a in the cross section shown in FIG. At the same time, the region is divided into a crystal region 10b which maintains the crystallinity without being affected by the arsenic ion implantation. At this time, as described above, with the implantation of arsenic ions, oxygen in the silicon oxide film is knocked on by the arsenic ions and introduced into the substrate. Then, the concentration of the knocked-on oxygen decreases as going downward. About this oxygen concentration,
As described above, it is known that there is a critical value (3.2 × 10 ¹⁹ atoms · cm ⁻³ ) at which the recovery rate at the time of annealing changes. Therefore, in this state, the amorphous region 10a is located immediately below the silicon oxide film 11 and includes a high-concentration oxygen region 10aa containing a relatively high concentration of oxygen equal to or higher than the critical value. It is divided into a low concentration oxygen region 10ab containing a relatively low concentration of oxygen.

Next, in step ST13, a low-concentration oxygen region 10ab (a region where the depth position from the upper surface of the silicon substrate 10 is 28 nm or more and 55 nm or less ) shown in FIG.
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, annealing is performed at a temperature T in step ST14. 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, a change in the thickness of the amorphous region 10a within a certain annealing time is detected using a spectroscopic ellipsometer, and the recovery rate 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 carried out with a region into which high-concentration oxygen is introduced in a sample wafer for temperature evaluation, or a high-concentration oxygen is introduced into 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 represented by a straight line as shown in FIG. 8 and the annealing temperature 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, for example, in a thermal CVD apparatus for depositing a silicon oxide film at a place where a product wafer is actually installed. 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 typical portion inside a 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 increased. Can be measured accurately.

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

(Third Embodiment) Next, a description will be given of a third embodiment according 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 only arsenic (As) 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 an amorphous region formed by Ge implantation and an 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 sample wafer for evaluation 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 measuring 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 that time, the temperature range is 425 ° C or more from FIG.
Since it can be grasped that the temperature is 520 ° C. or lower , an accurate temperature distribution can be measured by preparing a sample wafer having the entire surface of the wafer as the first amorphous region Ra and performing temperature measurement using this sample wafer. .

(Fourth Embodiment) Next, a fourth embodiment relating to ion implantation at a low temperature will be described. FIGS. 13A to 13D respectively show an amorphous region-a crystalline region formed by implanting arsenic (As) at a substrate temperature of 0 ° C., −10 ° C., −20 ° C., and −30 ° C. It is sectional drawing which shows the shape of the interface between them. Arsenic (As) is implanted at an accelerating voltage of 30
The keV and the dose are 3.0 × 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 injection near 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 diagram 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 in which the substrate temperature is lower than -10.degree. 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.

As discussed in connection with 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 high until the boundary becomes clear or the unevenness of the interface is reduced. 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 value of use 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 to a value equal to or higher than 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 described later, by implanting arsenic ions or the like at a relatively high dose (for example, about 4 × 10 ¹⁵ atoms · cm ⁻² ), an amorphous region and a crystalline region formed by ion implantation are formed. Can be clearly defined. However, since a natural oxide film is generally present on the surface of the region to be silicided (source / drain region), when a high concentration of arsenic ion or the like is implanted, oxygen is knocked on to the region. It is injected (see FIG. 2). As a result, it becomes difficult to reliably suppress the generation of oxygen-induced defects.

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 a 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, the same effect can be obtained with the same dose even if Ge is implanted instead of As. 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 are C, Si, G
It refers to elements such as e, Sn, and Pb.

FIG. 16 shows a boundary between an amorphous region formed by implanting 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. It is a TEM photograph which shows the structure of 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.

The ion species is not limited to Ge, but may be elements such as C, Si, Sn, and Pb. 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, but even in such a case, the low-temperature annealing ( 300 ° C. or higher) 450 ° C or less
By applying below), it is possible to reduce the clear or the interface roughness of both boundaries.

In the present embodiment, the recovery that progresses until the boundary that does not appear clearly gradually becomes clear and 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, a flattened silicide layer can be formed by performing a silicidation process using the amorphous region formed according to the present embodiment.

(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 view 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 performing temperature measurement 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 rear 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 measurement method in each of the above embodiments is stored in a recording medium utilizing magnetic, optical, and electric characteristics, and is used in a semiconductor device manufacturing process using this recording medium. Can be.

[0106]

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. See Usui, Pulsed laser-induced amorphization of silicon films, J. Am. Appl. Phys. , United States, August 1, 1991, 70 (3), p. p. 1281-1289

Claims (14)

(57) [Claims] An amorphous region of a substrate is heated for a predetermined time to determine a recovery rate at which the amorphous region is recrystallized, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region at the time of heating, wherein the recovery rate during the heating is substantially constant from the start of heating in the amorphous region formed in the semiconductor region of the substrate. A method for preparing a sample for temperature measurement, characterized in that oxygen is doped at a critical concentration in order to obtain a sample. 2. The method according to claim 1, wherein the critical value is 3.2 × 10 ¹⁹ atoms · cm ⁻³ . 3. The method for producing a sample for temperature measurement according to claim 1 , wherein an oxide film is formed on the semiconductor region of the substrate before doping with oxygen. A method for preparing a temperature measurement sample, wherein the amorphous region is formed by implanting impurities into the semiconductor region from above the oxide film. 4. The method for preparing a temperature measurement sample according to claim 1 , wherein a natural oxide film on the semiconductor region is removed under reduced pressure before doping with the oxygen. A method for preparing a sample for temperature measurement, comprising doping by ion implantation of oxygen into a sample. 5. A recovery rate at which the amorphous region of the substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. A method for preparing a temperature measurement sample for measuring a temperature of an amorphous region at the time of forming, wherein an amorphous region is formed by performing ion implantation of a group IV element in a semiconductor region of a substrate. How to make a sample for measurement. 6. The method for preparing a temperature measurement sample according to claim 5, wherein the ion implantation has a dose of 1 × 10 ¹⁵ atoms.
A method for preparing a temperature measurement sample, wherein Ge ions are implanted under a condition of cm ⁻² or more. 7. A recovery rate at which the amorphous region of the substrate is heated for a certain period of time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region at a time, wherein at least one of arsenic (As), phosphorus (P), a halogen element and an inert gas element is provided in a semiconductor region of a substrate. A method for preparing a temperature measurement sample, wherein an amorphous region is formed by performing any one of ion implantation. 8. A recovery rate at which the amorphous region of the substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a previously prepared relationship between the recovery rate of the amorphous region and the heating temperature. A method for preparing a temperature measurement sample for measuring the temperature of an amorphous region at the time of forming a plurality of amorphous regions by performing ion implantation under different conditions at a plurality of locations in a semiconductor region of a substrate. A method for preparing a sample for temperature measurement, characterized in that: 9. The method for preparing a temperature measurement sample according to claim 8 , wherein, during the ion implantation, ion species to be implanted into the plurality of locations or ion implantation conditions are made different. How to make a sample for use. 10. The method for producing a sample for temperature measurement according to claim 8, wherein the substrate is in a wafer state, and the four locations are divided into four parts in a plan view. A temperature measurement method characterized by being an area. 11. A recovery rate at which an amorphous region of a substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. Forming a temperature measurement sample for measuring a temperature of an amorphous region at the time of forming a first amorphous region by performing ion implantation into a first semiconductor region on an upper surface of a substrate (a). )
Forming a second amorphous region by performing ion implantation on a second semiconductor region on the back surface of the substrate (b)
And a method for preparing a sample for temperature measurement. 12. A recovery rate at which an amorphous region of a substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. Forming a temperature measurement sample for measuring the temperature of the amorphous region at the time of forming the first amorphous region by performing ion implantation on the first semiconductor region on the upper surface of the substrate ( a), and (b) forming the second amorphous region by performing the above-described ion implantation into the second semiconductor region on the back surface of the substrate, wherein the temperatures of the first and second amorphous regions are adjusted. When the temperature is determined, a sample capable of determining the thermal conductivity of the substrate from the temperature difference between the first and second amorphous regions is formed. How to make a sample for temperature measurement. 13. A recovery rate at which an amorphous region of a substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. A method for preparing a temperature measurement sample for measuring the temperature of the amorphous region at the time of ion implantation, wherein the ion implantation is performed in the semiconductor region of the substrate under the condition that the substrate temperature is lower than −10 ° C. Forming a sample for temperature measurement. 14. A recovery rate at which the amorphous region of the substrate is heated for a predetermined time to recrystallize the amorphous region, and the heating rate is determined based on a relationship between a previously prepared recovery rate of the amorphous region and a heating temperature. A method for preparing a temperature measurement sample for measuring a temperature of an amorphous region at the time of forming an amorphous region by ion implantation in a semiconductor region of a substrate; (B) performing annealing at a temperature in the range of 300 ° C. or more and 450 ° C. or less .