JP2000088806A - Substance characteristic evaluating method and substance characteristic evaluating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly take at high accuracy a diffusion coefficient and a concentration distribution of chemical species in a substance by comparing a temperature dependency of an elimination speed of an elimination substance determined based on a model with an actual data and determining a model parameter so as to correspond both temperature dependencies. SOLUTION: In the case where an SiO2 film formed on an Si substrate is allowed to stand in an air and a substance characteristic of the SiO2 film containing water is evaluated, a temperature-rising elimination spectrum of the SiO2 film is measured to obtain an actual data. Whereas a model representing a process that water is adsorbed on the SiO2 film surface, is diffused and is reacted and a process of a surface elimination of the surface water is previously prepared. A temperature dependency of water-elimination speed introduced based on the model and a temperature dependency of the actual elimination speed are compared and a model parameter is determined so as to correspond both temperature dependencies. Thereby, a diffusion activation energy, a diffusion frequency factor an elimination activation energy, an elimination frequency factor and a concentration distribution of chemical species (water, etc.), in the SiO2 film are determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for evaluating material properties, and more particularly, to a method for analyzing a thermal desorption spectrum and a method for evaluating material properties using the analysis method. Also,
The present invention relates to a semiconductor device having an interlayer film in which the behavior of an impurity in a film is controlled by using the material property evaluation method.

[0002]

2. Description of the Related Art As a conventional method, there has been the following method.

(1) A method in which a substance is heated and the chemical species thermally desorbed is analyzed.

When a solid substance is heated, the chemical species inside the substance,
The chemical species generated by the reaction inside the substance and the chemical species adsorbed on the surface of the substance are vaporized and desorbed to the outside of the substance.
Here, by measuring the heating time and temperature, and the amount and type of the desorbed chemical species, the relationship between the desorption amount (or desorption rate) of the chemical species and the temperature can be obtained. Conventionally, a method has been practiced in which a substance is heated at a constant heating rate and the type and amount of chemical species vaporized from the substance are measured by mass spectrometry (thermal desorption spectroscopy; PARedhead, Vacuum 12 ( 19
62) 203). A method for analyzing the desorption characteristics of chemical species by this method will be described below. In this method, desorption at the surface is regarded as an n-th desorption reaction, and the desorption activation energy and desorption frequency factor are estimated from the desorption reaction rate equation.
When the elimination reaction can be regarded as primary, the following (Equation 1) holds.

[0005]

E _a / k _B T _m = (A ₀ / α) exp [−E _a / k _B T _m ] (Equation 1) (where A ₀ : desorption frequency factor, E _a : desorption) Activation energy, α: heating rate, k _B : Boltzmann constant, T _m :
Changing variously the peak value) heating rate α of the Atsushi Nobori spectrum (usually vary about two orders of magnitude), by measuring the temperature T _m of a peak, the desorption activation energy E _a and desorption frequency factor A ₀ is found.

(2) A method for deriving a diffusion coefficient and a desorption reaction rate constant under a constant temperature condition.

When the concentration of a chemical species on the surface of a substance is high, the chemical species not only desorbs from the surface but also diffuses into the substance.

Have examined the surface concentration of cesium on graphite at various temperatures, and analyzed the relationship between the obtained time and the surface concentration as follows (K. Moeller and L. et al., 1993).
Holmlid, Surface Science, 204 (1988) 98-
112).

First, consider the mass balance of chemical species on the surface (Equation 2). (Equation 2) shows the change of the chemical species concentration on the surface. N _b (t) in (Equation 2) is expressed by (Equation 3) and (Equation 4)
Calculate by Next, from (Equation 2), the surface concentration C
_{By determining s} (t) and fitting the measured surface concentration over time curve, diffusion and desorption parameters are determined,
Find the diffusion coefficient and desorption rate constant. in this way,
It couples the diffusion phenomenon inside the substance and the desorption phenomenon on the substance surface. Therefore, the diffusion coefficient and the desorption rate constant can be obtained simultaneously by analysis.

[0010]

(Equation 2)

[0011]

(Equation 3)

[0012]

(Equation 4)

Where

[0014]

K = A ₀ exp [−E _a / k _B T (t)] (Equation 5) (where, A ₀ : desorption frequency factor, E _a : desorption activation energy, α: temperature rise Speed, k _B : Boltzmann's constant, T
(T): temperature at time t, f: chemical species incidence flu on the surface
x, C _b : concentration of chemical species in the substance, C _s : concentration of chemical species on the surface, D: diffusion coefficient, N _b : abundance of chemical species in the substance)

[0015]

The method of the above (1) is as follows.
It focuses only on the desorption of species on the surface of a substance.
Therefore, the diffusion coefficient (diffusion activation energy, diffusion frequency factor) and the concentration distribution of the chemical species in the substance cannot be obtained.

The method (2) has the following problems.

(A) Since the analysis is performed only in the isothermal process, it is difficult to determine the diffusion coefficient and the desorption rate constant in a wide temperature range in a short time. When (Equation 2) to (Equation 4) are used as they are in the heating process, the differentiation for each parameter of diffusion and desorption (necessary when optimizing parameters by least squares fit) is analytically calculated. Since it cannot be obtained, it takes time to evaluate.

(B) From only a single experimental result, the diffusion coefficient,
Since the desorption rate constant is determined, sufficient accuracy of the diffusion coefficient and the desorption rate constant cannot be obtained.

(C) Not applicable if the concentration of the chemical species in the substance is not clear.

An object of the present invention is to quickly and accurately determine the diffusion coefficient (diffusion activation energy, diffusion frequency factor) and the concentration distribution of a chemical species in a substance.

[0021]

The feature of the present invention to achieve the above object is that the desorbed substance adsorbed on the surface of the substance reacts in the substance, and the desorbed substance from the surface of the substance enters the gas phase. The temperature dependence of the desorption amount of the desorbed substance or the temperature dependence of the desorption rate determined based on a model representing the released surface desorption process, and the measured desorption amount of the desorbed substance And the temperature dependence of the desorption rate and the temperature dependence of the desorption rate, so that the temperature dependence of both correspond to the model parameters diffusion activation energy, diffusion frequency factor, desorption activation energy, The purpose is to determine the desorption frequency factor (or diffusion activation energy, diffusion frequency factor, reaction activation energy, reaction frequency factor, reaction order) and the concentration distribution of desorbed substances in a substance.

Here, the diffusion / desorption process is represented by (Equation 5) to (Equation 7). Although the temperature dependence of the diffusion coefficient D and the desorption rate constant (or reaction rate constant) k _i conforms to the Arrhenius equation, it is desirable to change to an optimal temperature dependence equation depending on the type of substance.

[0023]

(Equation 6)

[0024]

(Equation 7)

[0025]

(Equation 8)

Here,

[0027]

D = D ₀ exp [−E _d / k _B T (t)] (Equation 9)

[0028]

K _i = A _{0, i} exp [−E _ai / k _B T (t)] (Equation 10) (where, A ₀ : desorption frequency factor, E _a : desorption activation energy, k _B : Boltzmann's constant, T (t): temperature at time t, C _b : concentration of a chemical species in a substance, C _s : concentration of a chemical species on a surface, D: diffusion coefficient, k _i : desorption rate constant (or Reaction rate constant), D ₀ : diffusion frequency factor, E _d : diffusion activation energy, _ni : desorption order, C: molecular concentration, δ: thickness of the outermost layer, N: number of layers of desorption phenomenon, F: flux of impurities from the environment onto the film surface flux, S (T (t)): thermal desorption spectrum) First, the environmental conditions (substance production) where the substance was left according to (Equation 5) and (Equation 6) Calculate the concentration of the chemical species in the substance before measurement from the temperature, humidity, and time from the time of analysis to the time of analysis and measurement). Next, the temperature rising desorption spectrum can be reproduced by plotting the values on the left side of (Equation 7) while changing the temperature. Here, if the parameters of (Equation 5) to (Equation 7) are determined so as to reproduce the measured thermal desorption spectrum, diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor Can be requested. This makes it possible to quickly and easily widen the diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor, and chemical species concentration distribution of chemical species in a material over a wide range. It can be determined in a wide temperature range. Also, measurement and evaluation can be performed quickly (about 20 minutes to 2 hours).

In forming a thin film on a substrate, a film forming raw material is formed based on the obtained diffusion activation energy, the diffusion frequency factor, the desorption activation energy, the desorption frequency factor, and the concentration distribution. By changing the supply amount or the temperature of the substrate, the characteristics of the thin film can be kept constant irrespective of subtle changes in process conditions.

Another feature of the present invention resides in the use of a plurality of thermal desorption spectra obtained by measuring the same sample with different heating profiles. Thereby, a more accurate evaluation result can be obtained.

Further, by using a temperature-programmed desorption spectrum obtained by measuring a plurality of samples of the same kind and having different film thicknesses, it is possible to more reliably determine whether the peak in the spectrum is caused by diffusion or desorption reaction. Identification becomes possible.

In performing the material property evaluation method, if the rate of temperature rise of the substance is changed according to the temperature dependence of the amount of desorption of the desorbed substance or the curvature of the temperature dependence of the desorption rate,
It is possible to improve the measurement accuracy in a temperature region where the spectrum intensity changes rapidly.

In performing the material property evaluation method, the obtained temperature dependence of the desorption amount or desorption rate of the desorbed substance and the model parameters are stored in a storage device. By comparing the temperature dependence of the desorption amount or desorption rate of the desorbed substance with the temperature dependence of the desorption quantity or desorption rate of the desorbed substance, the model parameters If the initial value is determined, the time until the convergence of the model parameters can be reduced. In particular, when the sample of the temperature dependence of the desorption amount or the temperature dependence of the desorption rate of the stored desorption substance is the same as the sample under measurement, the measurement error near the peak can be reduced. .

Further, by connecting a plurality of thermal desorption spectra measuring devices and simultaneously measuring the thermal desorption spectra of a large number of samples, it is possible to improve the throughput or the measurement accuracy.

When the diffusion coefficient and desorption rate constant of global warming gases such as CO ₂ and CO and ozone depleting gases such as freon are measured using the material property evaluation method of the present invention, the sealing against these gases is obtained. The sealing performance of the material can be evaluated.

In manufacturing a semiconductor device, the method for evaluating material properties according to the present invention is used to determine the diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor, and substance of a desorbed substance in a substance. By controlling the concentration distribution of the desorbed substance in the semiconductor device, a semiconductor device having desirable properties (high water resistance, high heat resistance, etc.) can be manufactured.

According to the present invention, if the substance is a multilayer substance in which a plurality of substances are laminated, it is possible to clarify the segregation phenomenon in which the concentration of the desorbed substance increases or decreases at the interface between the constituent substances in the multilayer substance. Become.

[0038]

(Embodiment 1) A method for evaluating material properties according to a first embodiment of the present invention will be described. FIG. 1 shows a flow chart of the material property evaluation method of the present embodiment.

In this embodiment, S is formed by plasma CVD.
The material properties of the SiO ₂ film (film thickness 100 nm) formed on the i-base are evaluated. Water is 1 wt% on the SiO ₂ film.
%include. Water was taken in the film by leaving it in the air after producing the SiO ₂ film (leaving at 27 ° C. and 80% humidity for 7 days).

The heated desorption spectrum of this SiO ₂ film is measured. As a result, data on the temperature dependence of the water desorption rate (thermal desorption spectrum) is obtained.

According to the present invention, the thermal desorption spectrum is analyzed in accordance with the model shown in FIG. The following process is considered in the model of FIG.

(1) Water adsorbs on the SiO ₂ film surface and
Process step of diffusing into ₂ (2) water is reacted in SiO ₂ network (2
(SiOH → SiO ₂ + H ₂ O) (3) Surface desorption process in which water on the SiO ₂ surface is released into the gas phase Temperature dependence of the water desorption rate derived based on this model and the measured desorption amount or desorption The temperature dependence with the separation speed is compared, and the model parameters are determined so that the two dependencies correspond. The model parameters are diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor (or diffusion activation energy, diffusion frequency factor, reaction activation energy, reaction frequency factor) and substance A 5 is a concentration distribution of the substance B of FIG. In the model of FIG. 1, the thermal desorption spectrum is represented by (Equation 5) to (Equation 7). Diffusion coefficient D,
Although the temperature dependence of the desorption rate constant (or reaction rate constant) k _i conforms to the Arrhenius equation, it is desirable to change to an optimal temperature dependence equation depending on the type of the substance.

[0043]

(Equation 6)

[0044]

(Equation 7)

[0045]

(Equation 8)

Here,

[0047]

D = D ₀ exp [−E _d / k _B T (t)] (Equation 9)

[0048]

K _i = A _{0, i} exp [−E _ai / k _B T (t)] (Equation 10) (where, A ₀ : desorption frequency factor, E _a : desorption activation energy, k _B : Boltzmann's constant, T (t): temperature at time t, C _b : concentration of a chemical species in a substance, C _s : concentration of a chemical species on a surface, D: diffusion coefficient, k _i : desorption rate constant (or Reaction rate constant), D ₀ : diffusion frequency factor, E _d : diffusion activation energy, _ni : desorption order, C: molecular concentration, δ: thickness of the outermost layer, N: number of layers of desorption phenomenon, F: flux of impurities incident on the film surface from the environment, S (T (t)): thermal desorption spectrum) (Equation 5) is (a) a process in which chemical species in the environment are adsorbed on the film surface; (B) a process in which chemical species on the film surface diffuse into the film,
(C) shows the process in which the chemical species diffused from the film reaches the surface, and (d) the process in which the chemical species on the surface are released into the gas phase. (Equation 6) represents a diffusion process in the film. Further, the left side in (Equation 7) represents the desorption rate of the chemical species in the film.

Here, the process of taking in the chemical species (such as moisture) contained in the air into the film is considered. First, the environmental conditions in which the substance was left untreated (analysis and analysis after the substance was manufactured)
Temperature, humidity, and time until measurement) (Equation 5),
By solving (Equation 6), the concentration distribution of chemical species (such as water) in the film is calculated. Next, the temperature-induced desorption spectrum can be reproduced by plotting the values on the left side of (Equation 7) while changing the temperature condition according to the temperature-induced desorption spectrum measurement conditions. here,
If the parameters in (Equation 5) to (Equation 7) are determined (fitting) so as to reproduce the measured thermal desorption spectrum shown in FIG. 1, the diffusion activation energy, diffusion frequency factor, desorption activation The energy, desorption frequency factor and chemical species concentration distribution in the film can be determined. Also, measurement and evaluation can be performed quickly (about 20 minutes to 2 hours).

As described above, according to the present invention, the diffusion and desorption characteristics in a wide temperature range can be evaluated.

(Embodiment 2) In the material property evaluation method in the first embodiment, a method of executing parameter determination using a computer will be described. Here, the water to be measured is a water in a semiconductor insulating film (SiO ₂ film) deposited on a Si substrate by a plasma CVD method on a semiconductor wafer,
It is assumed that there is a thermal desorption spectrum measured at two or more film thicknesses. FIG. 2 shows a flowchart of a computer program for evaluating a thin film. First, the measured data of the thermal desorption spectrum, that is, the relationship between the temperature and the time and the desorbed gas amount is read into the memory of the computer. The data is smoothed by a noise filter and used for fitting.

Next, an initial value is set for each parameter. This initial value is used as the initial value of the parameter if the same type of film or a similar film has been measured before and a converged parameter record remains in the database of the computer. If the same type of film has not been measured, a possible parameter value is given as an initial value. The number of parameters is basically given by the same number of activation energy and frequency factor pairs as the number of peaks appearing in the spectrum.

In the case where two peaks appear, for example, diffusion of (a) two desorption activation energies and two desorption frequency factors, or (b) one desorption activation energy and one desorption frequency factor, A combination such as one activation energy and one diffusion frequency factor is conceivable. Here, it is difficult to determine which peak is strongly affected by diffusion (diffusion-controlled) and which peak is strongly affected by desorption (desorption-controlled) from a single thermal desorption spectrum.

On the other hand, when there are a plurality of data of the same type of film whose thickness is changed, if the thickness and the peak integrated intensity are correlated, it can be determined that the diffusion-limited peak and the non-correlated peak are the desorption-controlled. This makes it possible to correctly select a parameter pair. FIG. 3 shows the thickness dependence of the integrated intensity of the actually measured diffusion and desorption rate-limiting peaks. From FIG. 3, it can be seen that the intensity of the peak of the diffusion controlled is almost proportional to the film thickness, but the change of the intensity of the peak of the desorption controlled is small.

Next, the values on the left side of (Equation 5) to (Equation 7) for each temperature and time are obtained by substituting the initial values for the parameters.
Take the square of the difference between the calculated value and the measured value at each temperature, and take the sum at all points. The calculation is repeated while changing the parameters until the sum falls below the set tolerance (least squares fit). As soon as the sum of squares of the error falls below the allowable value,
The value of each parameter is stored in an external storage device of the computer.

Next, it is checked how much the converged parameters differ depending on the film thickness. Here, if the difference between the parameters is equal to or greater than a preset allowable range (usually 5% or more), the parameters are changed and the fitting is repeated. According to the above method, the material property evaluation in the present invention can be automatically performed, and a result with higher accuracy than when a single spectrum is evaluated can be obtained.

In this embodiment, when calculating the sum of error squares, if all the sums of error squares of spectra having different film thicknesses are integrated and fitting is performed (FIG. 4), the evaluation time can be further reduced. is there.

FIG. 5 shows a method for simultaneously evaluating the thermal desorption spectra measured in two or more kinds of heating profiles (or heating rates) in this embodiment. in this way,
Material properties are evaluated from thermal desorption spectra measured with a plurality of thermal profiles. According to this method, material property evaluation can be automatically performed with high accuracy.

In this embodiment, the same effect can be obtained even when the evaluation target is hydrogen in the silicon nitride film.

In this embodiment, the same effect can be obtained even when the evaluation target is water or hydrogen in a fluorine-containing SiO ₂ film, a polysiloxane or a film obtained by polymerizing TEOS (Tetraethylorthosilicate) by a plasma CVD method. Can be

(Embodiment 3) A material property evaluation apparatus according to a third embodiment of the present invention will be described. FIG. 6 shows a material property evaluation device. Here, an example of evaluating moisture contained in the semiconductor insulating film (SiO ₂ ) will be described.

The measurement system is a temperature control system 1, vacuum vessels 201 to
203, quadrupole mass spectrometers 31 to 33, data analysis system 4
And a power supply 6. The temperature control system 1 has a signal line 51
1 to 513, thermocouples 231 to 233 in the vacuum vessel
And the heaters 21 by the power supply systems 111-113.
1 to 213. Vacuum containers 201 to 203
Is always 1 × 1 by the connected vacuum pump 24.
It is maintained at a low pressure of 0 ^-6 Torr or less. The quadrupole mass spectrometers 31 to 33 are connected to the vacuum vessels 201 to 203 by tubes 311 to 313, respectively.
The gas generated from 223 is a quadrupole mass spectrometer 31 to 33
The type and amount are measured. The data analysis system 4 is connected to the temperature control system 1, the quadrupole mass spectrometers 31 to 33 and the display device 43 by signal lines 52, 53 and 54, respectively. Sample 221 set in the device
-223 will be described below.

Samples 221 to 223 are prepared as follows. A 220 nm SiO ₂ film is deposited on a Si substrate. Next, it is left in the air for one week. Finally, the thickness is 200 nm by chemical mechanical polishing (CMP), respectively.
After setting to 100 nm and 50 nm, the sample is cut out in a size of 1 cm square. Here, the temperature, humidity, standing time, CMP processing time, CMP processing temperature, and the like of the leaving environment are sent to the data analysis system 4 via the network. From these information, the data analysis system predicts the amount of water diffusing into the membrane from the external environment according to (Equation 5) to (Equation 7), and uses it as the initial water concentration distribution in the analysis.

The operation of the device at the time of measurement will be described below. Samples 221 to 223 are placed in a vacuum
1 to 213. The time change of the sample heating temperature is adjusted by the temperature control system 1. The time change of the temperature is recorded in the storage device 42 of the data analysis system. Further, the kind and amount of the gas generated from the substance by the heating are specified and recorded by the quadrupole mass spectrometer 3.

The computer 41 of the data analysis system performs the fitting according to (Equation 5) to (Equation 7) on the relationship between the temperature and the gas generation amount by the least square method. The fitting is
The process is repeated until the error becomes equal to or less than the set tolerance.
The number of fitting parameters is automatically prepared by the number of spectrum peaks, but can be arbitrarily changed by changing the computer program of the data analysis system.

After the fitting is completed, the parameters are displayed on the display device 43 of the data analysis system. Further, the data analysis system 4 compares the diffusion activation energy, the diffusion frequency factor, the desorption activation energy and the desorption frequency factor with the data in the storage device 42 and lists possible diffusion and desorption reactions. The information is displayed on the display device 43. The storage device 4 stores the measured spectrum and the parameter as a pair.
Record in 2. These measured spectra and parameters can be retrieved from the storage device 42 as needed, and can be displayed on the display device 43 or transferred to another computer via a network.

As described above, in the present invention, a material characteristic evaluation with high throughput can be performed by simultaneously performing a plurality of measurements and spectrum processing.

(Embodiment 4) In the second embodiment, an example will be described in which the temperature rate is changed during measurement according to the curvature of the thermal desorption spectrum.

In fitting a thermal desorption spectrum, fitting the vicinity of the peak accurately leads to more accurate results. Therefore, the temperature rising rate is changed according to the curvature of the spectrum, and the temperature control device is controlled so that the number of sampling points is increased at a portion having a large curvature.

By adopting the above-described heating method,
It is possible to evaluate material characteristics with higher accuracy.

(Embodiment 5) An example in which a temperature profile can be selected in the second embodiment will be described below. The temperature profile can be selected from the following three types.

(A) Constant heating rate. The heating rate is given by the measurer from the input device 44. Usually, it is set to 1 K / s.

(B) When the curvature of the spectrum is large, the heating rate is at most 0.5 K / s or less, and when the curvature of the spectrum is small, the heating rate is at least 2 K / s. The measurer gives the determination value of the large or small curvature from the input device 44.

(C) In the case where the same type of film has been measured and spectrum data is present, the rate of temperature rise is suppressed near the peak in the spectrum data (1 K / s → 0.2).
5K / s).

As described above, it is possible to select an optimum heating profile depending on the object to be measured.

(Embodiment 6) A method of forming a semiconductor insulating film using an apparatus for evaluating a material property of an SiO ₂ film according to a sixth embodiment of the present invention will be described below with reference to FIG.

The semiconductor insulating film forming apparatus includes a material property evaluation device 100, a sample carrying system 80, and a semiconductor insulating film depositing device 60. The semiconductor insulating film deposition apparatus 60 receives the supply of the film forming gas from the gas supply system 65, and the gas is exhausted by the gas exhaust system 64. The gas supply system 65 is controlled to open and close by a control device 90 and a valve 70. A part of the wafer on which the insulating film is formed is taken out by the sample carrying system 80 and sent to the material property evaluation apparatus 100. Material property evaluation device 10
A value of 0 sends the evaluation result to the control device 90, and the valve 70 is opened and closed based on the result. Further, the control device 90 controls the heater 67 based on the evaluation result to adjust the film forming temperature.

Next, the operation of the semiconductor insulating film forming apparatus shown in FIG. 7 will be described.

The result of the material property evaluation is sent to the valve control device 90 via the signal line 55. The valve control device 90 determines the SiO ₂ based on the transmitted evaluation results and assumed conditions (how much water should be blocked for how long).
The thickness of the protective film and the film forming temperature are determined. Based on the result, the control device determines the deposition time and the film formation temperature to perform the film formation.

By using such a film forming apparatus, the properties of the insulating film can be kept constant with respect to subtle changes in process conditions (pressure, temperature, gas flow rate, etc.).

Further, by using the method described in the sixth embodiment to suppress the product variation of the diffusion coefficient of the generated interlayer insulating film to, for example, 10% or less, water infiltration into the wafer in the production line is prevented. The quantity can be controlled accurately.

In the second embodiment, if a sample prepared by diffusing a global warming gas such as CO _{2 in a} gas sealing material is prepared and the diffusion coefficient and the desorption rate constant are measured, warming can be obtained. It is possible to determine whether the sealing performance that causes gas release is good or bad. In addition, the sealing performance of a gas that causes destruction of the ozone layer such as freon can be similarly determined.

(Embodiment 7) A case in which a multilayer material is used as a measurement sample when performing material property evaluation according to a seventh embodiment of the present invention will be described. Here, the multilayer material is two kinds of SiO ₂ films 1 and 2 having different diffusion coefficients (the film 1 has a diffusion activation energy = 15 kcal / mol, a diffusion frequency factor = 1 × 10 ⁻¹⁰ m ² / s, a film 2 is diffusion activation energy = 12 kcal / mol, diffusion frequency factor = 1 × 10 ⁻¹⁰ m ² /
s). 0.5K / s, 1K / s for the following three samples
The material characteristics were evaluated at a heating rate of 2 K / s.

(A) Thickness of film 1 = 100 nm, thickness of film 2 = 100 nm (b) Thickness of film 1 = 50 nm, thickness of film 2 = 100 nm (c) Thickness of film 1 = 100 nm As a result, the segregation coefficient was found to be 5.

[0085]

According to the present invention, the desorption activation energy of a chemical species from the surface of a substance, the desorption frequency factor, the diffusion activation energy of a chemical species in a substance, It is possible to quickly determine the diffusion frequency factor and the chemical species concentration in the film over a wide temperature range. Also, by fitting a plurality of spectra simultaneously, a highly accurate evaluation result can be obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart of a material property evaluation method according to the present invention.

FIG. 2 is a flowchart of a computer program for evaluating material properties according to the present invention.

FIG. 3 shows the film thickness dependence of diffusion-controlled and desorption-controlled peak intensities.

FIG. 4 is a flowchart of the material property evaluation device according to the present invention.

FIG. 5 is a flowchart of a material property evaluation device according to the present invention.

FIG. 6 is a flowchart of a semiconductor insulating film forming apparatus according to the present invention.

FIG. 7 is a flowchart of a semiconductor insulating film forming apparatus according to the present invention.

[Explanation of symbols]

1: temperature control system, 3, 31-33: quadrupole mass spectrometer
4 data analysis system, 6 power supply, 24 vacuum pump, 41
... Calculator, 42 ... Storage device, 43 ... Display device,
44: input device, 52 to 55, 511 to 513, signal line, 60: semiconductor insulating film deposition device, 64: gas exhaust system,
65: gas supply system, 67, 211 to 213: heater,
70 ... valve, 80 ... sample loading system, 90 ... control device, 1
00: Material property evaluation device, 111 to 113: Power supply system, 201 to 203: Vacuum container, 221-233: Sample,
231 to 233: thermocouple, 311 to 313: tube.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 8, 1998 (1998.10.
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction contents]

(1) Water adsorbs on the SiO ₂ film surface and
Process process (2) water are reacted in the SiO ₂ network to diffuse into ₂

Embedded image (3) Surface desorption process in which water on the SiO ₂ surface is released into the gas phase The temperature dependence of the water desorption rate derived based on this model and the temperature dependence of the measured desorption amount or desorption rate are described below. By comparison, model parameters are determined so that the two dependencies correspond. The model parameters are diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor (or diffusion activation energy, diffusion frequency factor, reaction activation energy, reaction frequency factor) and substance A 5 is a concentration distribution of the substance B of FIG. In the model of FIG. 1, the thermal desorption spectra are represented by (Equation 5) to (Equation 7). Diffusion coefficient D,
Although the temperature dependence of the desorption rate constant (or reaction rate constant) k _i conforms to the Arrhenius equation, it is desirable to change to an optimal temperature dependence equation depending on the type of the substance.

Claims (8)

[Claims] 1. A material property evaluation method for analyzing a desorption amount or a desorption rate of a desorbed substance generated outside from a substance by using a thermal desorption spectroscopy method, wherein the desorbed substance adsorbed on the surface of the substance is analyzed. Desorption of the desorbed substance determined based on a model representing a process in which the desorbed substance reacts in the substance, and a surface desorption process in which the desorbed substance is released into the gas phase from the surface of the substance. The temperature dependence of the desorption amount or the desorption rate is compared with the temperature dependence of the desorption amount or desorption rate of the desorbed substance measured, and the temperature dependence of both is determined. Correspondingly, a model parameter such as diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor of the desorbed substance and concentration distribution of the desorbed substance in the substance are obtained. Material property evaluation method. 2. A material property evaluation method for analyzing a desorption amount or a desorption rate of a desorbed substance generated from a substance to the outside by using a thermal desorption spectroscopy method. Desorption of the desorbed substance determined based on a model representing a process in which the desorbed substance reacts in the substance, and a surface desorption process in which the desorbed substance is released into the gas phase from the surface of the substance. The temperature dependence of the desorption amount or the desorption rate is compared with the temperature dependence of the desorption amount or desorption rate of the desorbed substance measured, and the temperature dependence of both is determined. Correspondingly, the diffusion activation energy, diffusion frequency factor, reaction activation energy, reaction frequency factor, reaction order, and reaction order of the desorbed substance, which are model parameters, and the concentration distribution of the desorbed substance in the substance are determined. Material property evaluation method characterized by . 3. The method according to claim 1, wherein a plurality of thermal desorption spectra obtained by measuring the same kind of sample with different heating profiles are used. 4. The method according to claim 1, wherein a temperature-programmed desorption spectrum obtained by measuring a plurality of samples of the same kind and having different film thicknesses is used. 5. The method according to claim 1, wherein the rate of temperature rise of the substance is changed in accordance with the determined temperature dependence of the amount of desorption of the desorbed substance or the temperature dependence of the desorption rate. The material property evaluation method of 1 or 2. 6. A thin film forming method for forming a thin film on a substrate, wherein the desorbed substance adsorbed on the surface of the substance reacts in the substance, and the desorbed substance is vaporized from the surface of the substance. Temperature dependence of the desorption amount or desorption rate of the desorbed substance determined based on a model representing the surface desorption process released into the phase, and the measured desorption substance Comparing the temperature dependence of the desorption amount or the temperature dependence of the desorption rate, and the diffusion activation energy and the diffusion frequency factor of the desorbed substance, which are model parameters so that the temperature dependence of the two correspond. , Desorption activation energy, desorption frequency factor, and concentration distribution of the desorbed substance in the substance; and the obtained diffusion activation energy, diffusion frequency factor, desorption activation energy, The desorption frequency factor And changing the supply amount of the film forming raw material or the temperature of the substrate based on the concentration distribution. 7. A thin film forming method for forming a thin film on a substrate, wherein the desorbed substance adsorbed on the surface of the substance reacts in the substance, and the desorbed substance is vaporized from the surface of the substance. Temperature dependence of the desorption amount or desorption rate of the desorbed substance determined based on a model representing the surface desorption process released into the phase, and the measured desorption substance Comparing the temperature dependence of the desorption amount or the temperature dependence of the desorption rate, and the diffusion activation energy and the diffusion frequency factor of the desorbed substance, which are model parameters so that the temperature dependence of the two correspond. Determining the activation energy of the reaction, the frequency factor of the reaction, the order of the reaction, and the concentration distribution of the desorbed substance in the substance. The determined diffusion activation energy, the diffusion frequency factor, and the activity of the reaction. Energy, Changing the supply amount of the film forming raw material or the temperature of the substrate based on the reaction frequency factor, the reaction order, and the concentration distribution. 8. A material property evaluation apparatus for analyzing a desorption amount or a desorption rate of a desorbed substance generated from a substance to the outside by using a thermal desorption spectroscopy method. Desorption of the desorbed substance determined based on a model representing a process in which the desorbed substance reacts in the substance, and a surface desorption process in which the desorbed substance is released into the gas phase from the surface of the substance. The temperature dependence of the desorption amount or the desorption rate is compared with the temperature dependence of the desorption amount or desorption rate of the desorbed substance measured, and the temperature dependence of both is determined. Material property evaluation to obtain the model parameters diffusion activation energy, diffusion frequency factor, desorption activation energy, desorption frequency factor, and concentration distribution of the desorbed substance in the substance which are the corresponding model parameters An apparatus, wherein said desorption is determined A material property evaluation device, comprising: a storage device for storing a temperature dependence of a desorption amount of a substance or a temperature dependence of a desorption rate and the model parameter.