CN108180879A - The valued methods and preparation method of ultra-thin silica membrane print - Google Patents
The valued methods and preparation method of ultra-thin silica membrane print Download PDFInfo
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- CN108180879A CN108180879A CN201711243418.5A CN201711243418A CN108180879A CN 108180879 A CN108180879 A CN 108180879A CN 201711243418 A CN201711243418 A CN 201711243418A CN 108180879 A CN108180879 A CN 108180879A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
- G01B21/08—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness for measuring thickness
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Abstract
The present invention is suitable for technical field of semiconductors, provides a kind of valued methods and preparation method of ultra-thin silica membrane print.The valued methods include：Substrate is cleaned in cleaning solution；The upper surface growth thickness of the substrate after cleaning is less than 10 nanometers of silica membrane；Definite value region is chosen, n measurement point is chosen in the definite value region；Determine the thickness evenness of the print；Determine the thickness stability of the print；Determine the partial uncertainty that measurer for thickness introduces；The Composite Seismogram and expanded uncertainty of the print are determined according to the partial uncertainty, the thickness evenness and the thickness stability.Print provided by the invention can be used for calibration ellipsometer measurement range in the measurement capability of below 10nm.By evaluating the thickness evenness, thickness stability and uncertainty of print, the confidence level of print calibration result can be learnt.
Description
Technical field
The invention belongs to technical field of semiconductors more particularly to a kind of ultra-thin silica membrane print valued methods and
Preparation method.
Background technology
In semiconductor applications, film thickness is an important parameter, and accurate measure to film thickness parameter is to protect
Demonstrate,prove the important means of device quality.Ellipsometer is mainly used for solving the problems, such as the measurement of film thickness.In order to ensure ellipsometer measurement
As a result accuracy needs to calibrate instrument using standard sample of photo.
At present, as the device feature size produced in microelectronic industry increasingly reduces, film thins down, and reaches
Below 10nm.But due to lack film thickness be less than 10nm standard sample of photo so that ellipsometer measurement range 10nm with
Under measurement capability can not calibrate.
Invention content
In view of this, the valued methods an embodiment of the present invention provides a kind of ultra-thin silica membrane print and preparation side
Method, to solve the problems, such as that measurement capability of the ellipsometer measurement range in below 10nm can not calibrate in the prior art.
The first aspect of the embodiment of the present invention provides a kind of valued methods of ultra-thin silica membrane print, including：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface；
Pass through the upper surface silicon dioxide thin film growth of the substrate of rapid thermal oxidation process after cleaning, the dioxy
The thickness of SiClx film is less than 10 nanometers；
Definite value region is chosen on the silica membrane, and n measurement point is chosen in the definite value region；
The first thickness of the n measurement points is measured using measurer for thickness, according to determining the first thickness
The thickness evenness of print；
The second thickness of m n measurement points is measured according to prefixed time interval using the measurer for thickness, is obtained
To m thickness average value, the thickness stability of the print is determined according to the m thickness average value；
Determine the partial uncertainty that the measurer for thickness introduces；
The synthesis of the print is determined according to the partial uncertainty, the thickness evenness and the thickness stability
Uncertainty and expanded uncertainty；
Wherein, n and m is the positive integer more than 1.
Optionally, the Composite Seismogram ucCalculation formula be：
The calculation formula of the expanded uncertainty U is：
U=2uc
Wherein, u1For the partial uncertainty that the measurer for thickness introduces, u2For thickness evenness, u3It is steady for thickness
It is qualitative.
Optionally, the first thickness that the n measurement points are measured using measurer for thickness, according to the described first thickness
Degree determines the thickness evenness of the print, including：
The first thickness of the n measurement points is measured, obtains n first thickness value, it will be in the n first thickness values
Thickness evenness of the difference of maxima and minima as the print.
Optionally, thickness stability u3Calculation formula be：
Wherein,Determining thickness average value is measured for ith,
Optionally, the measurer for thickness is ellipsometer；
The partial uncertainty for determining the measurer for thickness and introducing, including：
Build silica-film thickness and ellipse drift angle and the database of the correspondence of phase difference；
Using j-th of measurer for thickness duplicate measurements measurement point k times, the k groups angle of polarization and phase difference are obtained, according to
The k groups angle of polarization and phase difference build the normal distribution curve about the angle of polarization respectively and the normal distribution about phase difference is bent
Line；
H groups are chosen from the normal distribution curve about the angle of polarization and the normal distribution curve about phase difference
First angle of polarization and first phase difference, and h third thickness is obtained with the database matching, calculate the mark of the third thickness
Accurate poor, the standard deviation of the third thickness is the partial uncertainty that the measurer for thickness introduces；
Wherein, h and k is the positive integer more than 1.
Further, the structure silica-film thickness and ellipse drift angle and the database of the correspondence of phase difference,
Including：
Build structural model and dispersive model；Wherein, structural model is silicon substrate and the silica of silicon substrate upper surface
Film sets the dispersion parameters of silica, the dispersion parameters of silicon, lambda1-wavelength and incident angle；
According to the structural model and dispersive model structure silica-film thickness and the angle of polarization and phase difference relationship
Function；
Wherein, silica-film thickness and the function of the angle of polarization and phase difference relationship are obtained according to the following formula,
ρ is the elliptic function of silica membrane,For the amplitude reflectance in p-polarization direction,For s polarization directions
Amplitude reflectance, rpThe mould of amplitude reflectance for p-polarization direction, rsThe mould of amplitude reflectance for s polarization directions,For p-polarization phase,For s polarization phases, Ψ is the angle of polarization, and Δ is phase difference, r1sFriendship for air and silica membrane
The s directions polarized component fresnel reflection coefficient at interface, r2sFor the s directions of silica membrane and the interface of substrate polarization point
Measure fresnel reflection coefficient, δ1To be tested the phase thickness of film layer, n0For air refraction, θ0For incident angle, n1For titanium dioxide
Silicon thin film refractive index, θ1For the incidence angle in silica membrane, n2For refractive index of substrate, θ2For refraction angle in substrate, r1pFor boundary
The p directions polarized component fresnel reflection coefficient in face 1, r2pFor the p directions polarized component fresnel reflection coefficient at interface 2, d1For
Silica-film thickness, λ lambda1-wavelengths；
According to the function, the corresponding of silica membrane that thickness is 0 to 10 nanometer and the angle of polarization and phase difference is determined
Relationship.
Further, it is described from the normal distribution curve about the angle of polarization and the normal distribution about phase difference
First angle of polarization of h groups and first phase difference are chosen in curve, and h third thickness is obtained with the database matching, including：
1 first angle of polarization is chosen from the normal distribution curve about the angle of polarization, from described about phase difference
1 first phase difference is chosen in normal distribution curve；
Using method of seeking all over, calculate first angle of polarization and the first phase difference and each group second in database is inclined
The evaluation function value for angle and the second phase difference of shaking, wherein, in first angle of polarization and the first phase difference and database
The evaluation function of second angle of polarization of jth group and second phase difference is：
For the value of j-th of evaluation function, ΨjFor the value of second angle of polarization of jth group in database, ΔjFor database
In jth group second phase difference value, ΨexpThe value of first angle of polarization for selection, ΔexpFirst phase difference for selection
Value；
Choose second angle of polarization for making the evaluation function value minimum and the corresponding silica membrane of second phase difference
Thickness is as third thickness；
It repeats to choose 1 first angle of polarization from the normal distribution curve about the angle of polarization, from described about phase
The step of 1 first phase difference is chosen in the normal distribution curve of difference, until obtaining h third thickness.
Optionally, substrate in cleaning solution is cleaned, removes the impurity of the substrate surface, including：
The substrate is put into the first cleaning solution that temperature is 80 DEG C to 90 DEG C and is cleaned 10 minutes to 15 minutes；Wherein,
Mixed solution of first cleaning solution for distilled water, ammonium hydroxide and hydrogen peroxide, the volume ratio of distilled water, ammonium hydroxide and hydrogen peroxide
It is 4:1:1；
By the substrate distilled water flushing to neutrality；
The substrate is cleaned 2 minutes to 5 minutes in a solution of hydrofluoric acid；
By the substrate distilled water flushing to neutrality；
The substrate is put into temperature to be cleaned 10 minutes to 15 minutes in 80 DEG C to 90 DEG C second cleaning solutions；Wherein, institute
The mixed solution that the second cleaning solution is distilled water, hydrochloric acid and hydrogen peroxide is stated, the volume ratio of distilled water, hydrochloric acid and hydrogen peroxide is
4:1:1；
By the substrate distilled water flushing to neutrality；
The substrate is dried up with nitrogen.
Optionally, the thickness of the silica membrane is 2 nanometers to 5 nanometers.
Second aspect of the embodiment of the present invention provides a kind of preparation method of ultra-thin silica membrane print, including：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface；
Pass through the upper surface silicon dioxide thin film growth of the substrate of rapid thermal oxidation process after cleaning, the dioxy
The thickness of SiClx film is less than 10 nanometers.
Existing advantageous effect is the embodiment of the present invention compared with prior art：Ultra-thin dioxy provided in an embodiment of the present invention
SiClx film print can be used for calibration ellipsometer measurement range in the measurement capability of below 10nm.By using measurer for thickness
Measure the first thickness of n measurement point in definite value region, it may be determined that the thickness evenness of print is filled by using thickness measure
Put the second thickness that m n measurement point is measured according to prefixed time interval, it may be determined that the thickness stability of print determines thickness
The partial uncertainty that measuring device introduces is spent, it is finally true further according to partial uncertainty, thickness evenness and thickness stability
The Composite Seismogram and expanded uncertainty of random sample piece.Thickness evenness, the thickness that print can be evaluated by this method are steady
Qualitative and uncertainty, so as to learn the confidence level of print calibration result.
Description of the drawings
It to describe the technical solutions in the embodiments of the present invention more clearly, below will be to embodiment or description of the prior art
Needed in attached drawing be briefly described, it should be apparent that, the accompanying drawings in the following description be only the present invention some
Embodiment, for those of ordinary skill in the art, without having to pay creative labor, can also be according to these
Attached drawing obtains other attached drawings.
Fig. 1 is the realization flow signal of the valued methods for the ultra-thin silica membrane print that the embodiment of the present invention one provides
Figure；
Fig. 2 is the structure diagram for the ultra-thin silica membrane print that the embodiment of the present invention one provides；
Fig. 3 is that the thickness for the ultra-thin silica membrane print that the nominal thickness that the embodiment of the present invention one provides is 2nm is bent
Line chart；
Fig. 4 is that the thickness for the ultra-thin silica membrane print that the nominal thickness that the embodiment of the present invention one provides is 5nm is bent
Line chart；
Fig. 5 is the structural model schematic diagram that the embodiment of the present invention one provides.
Specific embodiment
In being described below, in order to illustrate rather than in order to limit, it is proposed that such as tool of particular system structure, technology etc
Body details, to understand thoroughly the embodiment of the present invention.However, it will be clear to one skilled in the art that there is no these specifically
The present invention can also be realized in the other embodiments of details.In other situations, it omits to well-known system, device, electricity
Road and the detailed description of method, in case unnecessary details interferes description of the invention.
In order to illustrate technical solutions according to the invention, illustrated below by specific embodiment.
Embodiment one
It please refers to Fig.1, the valued methods of ultra-thin silica membrane print include：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface by step S101.
Optionally, the specific implementation of step S101 is：By the substrate be put into temperature be 80 DEG C to 90 DEG C first
It is cleaned 10 minutes to 15 minutes in cleaning solution；Wherein, first cleaning solution is molten for the mixing of distilled water, ammonium hydroxide and hydrogen peroxide
Liquid, the volume ratio of distilled water, ammonium hydroxide and hydrogen peroxide is 4:1:1；By the substrate distilled water flushing to neutrality；By the lining
Bottom is cleaned 2 minutes to 5 minutes in a solution of hydrofluoric acid；By the substrate distilled water flushing to neutrality；The substrate is put into
Temperature is to be cleaned 10 minutes to 15 minutes in 80 DEG C to 90 DEG C second cleaning solutions；Wherein, second cleaning solution is distilled water, salt
The mixed solution of acid and hydrogen peroxide, the volume ratio of distilled water, hydrochloric acid and hydrogen peroxide is 4:1:1；The substrate is distilled
Water is rinsed to neutrality；The substrate is dried up with nitrogen.
It is thin to grow silica by the upper surface of the substrate of rapid thermal oxidation process after cleaning by step S102
Film, the thickness of the silica membrane are less than 10 nanometers.
In embodiments of the present invention, the silica-film thickness that is grown by rapid thermal oxidation process is controllable, uniformity
It is good.By the way that growth temperature, oxidization time and oxygen content is controlled to obtain the silica membrane of required thickness.For example, growth mark
When thickness is referred to as 2 nanometers of silica membrane, maximum temperature is 800 DEG C, and oxidization time is 30 seconds, oxygen content 10%,
Other gases are argon gas.When growing the silica membrane that nominal thickness is 5 nanometers, maximum temperature is 1000 DEG C, oxidization time
It it is 90 seconds, oxygen content 10%, other gases are argon gas.
Optionally, the thickness of the silica membrane is 2 nanometers to 5 nanometers
Step S103 chooses definite value region on the silica membrane, and n measurement is chosen in the definite value region
Point.Wherein, n is more than 1 positive integer.
In embodiments of the present invention, substrate chooses 4 inches of Silicon Wafer, and in the upper surface of Silicon Wafer, growth silica is thin
After film, definite value region is chosen, and n measurement point is chosen in definite value region.For example, as described in Figure 2, in silica membrane
Definite value region 202 is chosen in print 201, definite value region 202 is a diameter of 10 millimeters of circle, and 5 are chosen in definite value region 202
Measurement point 203.Wherein, definite value region 202 can be located at the middle part of silica membrane print 201 or close to edge, each
Distribution relation of the measurement point 203 in definite value region 202 not limits.
Step S104 measures the first thickness of the n measurement points using measurer for thickness, according to the first thickness
Determine the thickness evenness of the print.
Optionally, the specific implementation of step S104 is：The first thickness of n measurement points is measured, obtains n the
One thickness value, using the difference of the maxima and minima in the n first thickness values as the thickness evenness of the print.Its
In, n is the positive integer more than 1.
In embodiments of the present invention, measurer for thickness is ellipsometer, and measurement point can be 5, be distinguished using ellipsometer
The first thickness of 5 measurement points is measured, 5 first thickness values are obtained, by the maxima and minima in 5 first thickness values
Thickness evenness of the difference as print.For example, as shown in table 1, nominal thickness is the thickness of 2 nanometers of silica membrane print
Uniformity is 0.05 nanometer, and the thickness evenness for the silica membrane print that nominal thickness is 5 nanometers is 0.06 nanometer.
The thickness evenness of 1 print of table
Step S105 measures the of a measurement points of m n using the measurer for thickness according to prefixed time interval
Two thickness obtain m thickness average value, and the thickness stability of the print is determined according to the m thickness average value.Wherein, n
It is the positive integer more than 1 with m.
Optionally, thickness stability u3Calculation formula be：
Wherein,Determining thickness average value is measured for ith；
In embodiments of the present invention, thickness stability reaction silica-film thickness changes with time rule.For example,
5 measurement points are chosen, the second thickness of this primary 5 measurement points is measured every other month, measures 12 times altogether, according to formula (2)
The average value for 5 measurement point second thickness that ith measures is calculated, finally according to the stability of formula (1) calculated thickness.
Wherein, djThickness for j-th of measurement point in being measured in ith.
Fig. 3 is the change of the average thickness of 5 measurement points of silica membrane print that nominal thickness is 2 nanometers at any time
Law, thickness stability are 0.05 nanometer, and Fig. 4 is 5 measurement points of the silica membrane print that nominal thickness is 5 nanometers
Average thickness change with time rule, thickness stability is 0.05 nanometer.
Step S106 determines the partial uncertainty that the measurer for thickness introduces.
Optionally, the measurer for thickness is ellipsometer.The specific implementation of step S106 is：It is described determining described
The partial uncertainty that measurer for thickness introduces, including：
Build silica-film thickness and ellipse drift angle and the database of the correspondence of phase difference；
Using j-th of measurer for thickness duplicate measurements measurement point k times, the k groups angle of polarization and phase difference are obtained, according to
The k groups angle of polarization and phase difference build the normal distribution curve about the angle of polarization respectively and the normal distribution about phase difference is bent
Line；
H groups are chosen from the normal distribution curve about the angle of polarization and the normal distribution curve about phase difference
First angle of polarization and first phase difference, and h third thickness is obtained with the database matching, calculate the mark of the third thickness
Accurate poor, the standard deviation of the third thickness is the partial uncertainty that the measurer for thickness introduces；
Wherein, h and k is the positive integer more than 1.
Further, the structure silica-film thickness and ellipse drift angle and the database of the correspondence of phase difference,
Including：
Build structural model and dispersive model；Wherein, structural model is silicon substrate and the silica of silicon substrate upper surface
Film sets the dispersion parameters of silica, the dispersion parameters of silicon, lambda1-wavelength and incident angle；
According to the structural model and dispersive model structure silica-film thickness and the angle of polarization and phase difference relationship
Function；
Wherein, silica-film thickness and the function of the angle of polarization and phase difference relationship are obtained according to the following formula,
ρ is the elliptic function of silica membrane,For the amplitude reflectance in p-polarization direction,For s polarization directions
Amplitude reflectance, rpThe mould of amplitude reflectance for p-polarization direction, rsThe mould of amplitude reflectance for s polarization directions,For p-polarization phase,For s polarization phases, Ψ is the angle of polarization, and Δ is phase difference, r1sFriendship for air and silica membrane
The s directions polarized component fresnel reflection coefficient at interface, r2sFor the s directions of silica membrane and the interface of substrate polarization point
Measure fresnel reflection coefficient, δ1To be tested the phase thickness of film layer, n0For air refraction, θ0For incident angle, n1For titanium dioxide
Silicon thin film refractive index, θ1For the incidence angle in silica membrane, n2For refractive index of substrate, θ2For refraction angle in substrate, r1pFor boundary
The p directions polarized component fresnel reflection coefficient in face 1, r2pFor the p directions polarized component fresnel reflection coefficient at interface 2, d1For
Silica-film thickness, λ lambda1-wavelengths；
According to the function, the corresponding of silica membrane that thickness is 0 to 10 nanometer and the angle of polarization and phase difference is determined
Relationship.
In embodiments of the present invention, structural model is as shown in figure 5, structural model includes silicon substrate 501 and silicon substrate upper table
The silica membrane 502 in face.Dispersion parameters of the dispersive model for silicon and silica, wherein, the dispersion parameters of silica
For n1=1.46, the dispersion parameters of silicon are n2=3.875-0.016i, n1For silica membrane refractive index, n2It is reflected for substrate
Rate.Incident wavelength selects common wavelength X=632.8nm, the angle that incident angle is applicable in for spectroscopic ellipsometer, the present embodiment
Middle incident angle θ0=65 °.Silica-film thickness and the angle of polarization and phase can be obtained according to formula (3) to formula (6)
The function of poor relationship, i.e.,
f(d1)=tan ψ ejΔ (7)
According to formula (7) it is found that silica-film thickness is corresponded with the angle of polarization and phase difference, silica membrane
After thickness determines, unique one group of angle of polarization and phase difference can be obtained.According to formula (7), it is 0 to 10 nanometer to determine thickness
The correspondence of silica membrane and the angle of polarization and phase difference obtains silica-film thickness and ellipse drift angle and phase difference
The database of correspondence, wherein, 0.02 nanometer is divided between thickness.
Further, it is described from the normal distribution curve about the angle of polarization and the normal distribution about phase difference
First angle of polarization of h groups and first phase difference are chosen in curve, and h third thickness is obtained with the database matching, including：
1 first angle of polarization is chosen from the normal distribution curve about the angle of polarization, from described about phase difference
1 first phase difference is chosen in normal distribution curve；
Using method of seeking all over, calculate first angle of polarization and the first phase difference and each group second in database is inclined
The evaluation function value for angle and the second phase difference of shaking, wherein, in first angle of polarization and the first phase difference and database
The evaluation function of second angle of polarization of jth group and second phase difference is：
For the value of j-th of evaluation function, ΨjFor the value of second angle of polarization of jth group in database, ΔjFor database
In jth group second phase difference value, ΨexpThe value of first angle of polarization for selection, ΔexpFirst phase difference for selection
Value；
Choose second angle of polarization for making the evaluation function value minimum and the corresponding silica membrane of second phase difference
Thickness is as third thickness；
It repeats to choose 1 first angle of polarization from the normal distribution curve about the angle of polarization, from described about phase
The step of 1 first phase difference is chosen in the normal distribution curve of difference, until obtaining h third thickness.
In embodiments of the present invention, using j-th of spectroscopic ellipsometer duplicate measurements measurement point k times, the k group angles of polarization are obtained
And phase difference, the expected value and standard deviation of calculated angle of polarization and phase difference, builds the normal distribution curve about the angle of polarization respectively
With the normal distribution curve about phase difference.For example, using spectroscopic ellipsometer j-th of measurement measurement point 6 times, 6 groups of acquisition is inclined
Shake angle and phase difference, calculates the desired value and variance of phase difference and the angle of polarization respectively, builds bent about the normal distribution of the angle of polarization
Line and the normal distribution curve about phase difference.Table 2 is the silica membrane print and nominal thickness that nominal thickness is 2 nanometers
For 5 nanometers of the angles of polarization of silica membrane print and the desired value of phase difference and variance.
2 expected value and standard deviation of table
Use the uncertainty of measurement of MCM methods (monte carlo method) evaluation spectroscopic ellipsometer.From about the angle of polarization
Normal distribution curve in randomly select 1 the first angle of polarization Ψexp, selected at random from the normal distribution curve about phase difference
Take 1 first phase difference Δexp, obtain one group of (Ψexp, Δexp), by (Ψexp, Δexp) with database in (Ψj, Δj) progress
Match, wherein, j=1,2,3 ..., l, matching process is：(Ψ is calculated according to evaluation function (6)exp, Δexp) with database in
(Ψj, Δj) evaluation function value, (the Ψ of evaluation function value value minimum will be madej, Δj) corresponding thickness as third thickness,
It repeats step and 1 the first angle of polarization Ψ is randomly selected from the normal distribution curve about the angle of polarizationexp, until obtaining h third
Thickness.For example, when h is 10000, the silica membrane print spectroscopic ellipsometer that nominal thickness is 2 nanometers introduces not
Degree of certainty component is 0.04 nanometer, and the silica membrane print spectroscopic ellipsometer that nominal thickness is 5 nanometers introduces not true
Surely degree component is 0.04 nanometer.
Step S107, according to determining the partial uncertainty, the thickness evenness and the thickness stability
The Composite Seismogram and expanded uncertainty of print.
Optionally, the Composite Seismogram ucCalculation formula be：
The calculation formula of expanded uncertainty U is：
U=2uc (10)
u1For the partial uncertainty that the spectroscopic ellipsometer introduces, u2For thickness evenness, u3For thickness stability.
In embodiments of the present invention, the partial uncertainty u introduced according to spectroscopic ellipsometer1, thickness evenness u2And thickness
Spend stability u3It is the titanium dioxide that nominal thickness is 2 nanometers to calculate Composite Seismogram component and expanded uncertainty component, table 3
Silicon thin film print and the uncertainty of silica membrane print that nominal thickness is 5 nanometers.As it can be seen that nominal thickness is 2 nanometers
Silica membrane print and nominal thickness be 5 nanometers silica membrane print uncertainty very little, illustrate to measure
Credible result degree is very high.
3 uncertainty of table
| Nominal thickness | u1 | u2 | u3 | Composite Seismogram | Expanded uncertainty |
| 2nm | 0.05nm | 0.05nm | 0.05nm | 0.09nm | 0.18nm |
| 5nm | 0.06nm | 0.06nm | 0.05nm | 0.10nm | 0.20nm |
Ultra-thin silica membrane print provided in an embodiment of the present invention can be used for calibration ellipsometer measurement range in 10nm
Following measurement capability.The first thickness of n measurement point in definite value region is measured by using measurer for thickness, it may be determined that
The thickness evenness of print measures second thickness of m n measurement point by using measurer for thickness according to prefixed time interval
Degree, it may be determined that the thickness stability of print determines the partial uncertainty that measurer for thickness introduces, finally further according to not true
Surely the Composite Seismogram and expanded uncertainty that component, thickness evenness and thickness stability determine print are spent.Pass through the party
Method can evaluate the thickness evenness, thickness stability and uncertainty of print, can so as to learn print calibration result
Reliability.
Embodiment two
A kind of preparation method of ultra-thin silica membrane print, including：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface；
Pass through the upper surface silicon dioxide thin film growth of the substrate of rapid thermal oxidation process after cleaning, the dioxy
The thickness of SiClx film is less than 10 nanometers.
In embodiments of the present invention, the substrate is put into the first cleaning solution that temperature is 80 DEG C to 90 DEG C and cleans 10 points
Clock was to 15 minutes；Wherein, first cleaning solution be distilled water, ammonium hydroxide and hydrogen peroxide mixed solution, distilled water, ammonium hydroxide and
The volume ratio of hydrogen peroxide is 4:1:1；By the substrate distilled water flushing to neutrality；By the substrate in a solution of hydrofluoric acid
Cleaning 2 minutes to 5 minutes；By the substrate distilled water flushing to neutrality；It is 80 DEG C to 90 DEG C that the substrate is put into temperature
It is cleaned 10 minutes to 15 minutes in second cleaning solution；Wherein, second cleaning solution is the mixed of distilled water, hydrochloric acid and hydrogen peroxide
Solution is closed, the volume ratio of distilled water, hydrochloric acid and hydrogen peroxide is 4:1:1；By the substrate distilled water flushing to neutrality；By institute
Substrate is stated to be dried up with nitrogen.
By rapid thermal oxidation process grow silica-film thickness is controllable, uniformity is good.By controlling growth temperature
Degree, oxidization time and oxygen content obtain the silica membrane of required thickness.For example, growth nominal thickness is the two of 2 nanometers
During silicon oxide film, maximum temperature is 800 DEG C, and oxidization time is 30 seconds, oxygen content 10%, other gases are argon gas.It is raw
When long nominal thickness is 5 nanometers of silica membrane, maximum temperature is 1000 DEG C, and oxidization time is 90 seconds, and oxygen content is
10%, other gases are argon gas.
Grown silica membrane of the embodiment of the present invention by rapid thermal oxidation process after cleaning, titanium dioxide
Silicon film thickness is controllable, uniformity is good.
It should be understood that the size of the serial number of each step is not meant to the priority of execution sequence, each process in above-described embodiment
Execution sequence should determine that the implementation process without coping with the embodiment of the present invention forms any limit with its function and internal logic
It is fixed.
Embodiment described above is merely illustrative of the technical solution of the present invention, rather than its limitations；Although with reference to aforementioned reality
Example is applied the present invention is described in detail, it will be understood by those of ordinary skill in the art that：It still can be to aforementioned each
Technical solution recorded in embodiment modifies or carries out equivalent replacement to which part technical characteristic；And these are changed
Or replace, the spirit and scope for various embodiments of the present invention technical solution that it does not separate the essence of the corresponding technical solution should all
It is included within protection scope of the present invention.
Claims (10)
1. a kind of valued methods of ultra-thin silica membrane print, which is characterized in that including：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface；
Pass through the upper surface silicon dioxide thin film growth of the substrate of rapid thermal oxidation process after cleaning, the silica
The thickness of film is less than 10 nanometers；
Definite value region is chosen on the silica membrane, and n measurement point is chosen in the definite value region；
The first thickness of the n measurement points is measured using measurer for thickness, the print is determined according to the first thickness
Thickness evenness；
The second thickness of m n measurement points is measured according to prefixed time interval using the measurer for thickness, obtains m
A thickness average value determines the thickness stability of the print according to the m thickness average value；
Determine the partial uncertainty that the measurer for thickness introduces；
Determine that the synthesis of the print is not true according to the partial uncertainty, the thickness evenness and the thickness stability
Fixed degree and expanded uncertainty；
Wherein, n and m is the positive integer more than 1.
2. the valued methods of ultra-thin silica membrane print as described in claim 1, which is characterized in that the synthesis is not true
Surely u is spentcCalculation formula be：
The calculation formula of the expanded uncertainty U is：
U=2uc
Wherein, u1For the partial uncertainty that the measurer for thickness introduces, u2For thickness evenness, u3For thickness stability.
3. the valued methods of ultra-thin silica membrane print as described in claim 1, which is characterized in that described to use thickness
Measuring device measures the first thickness of the n measurement points, and the thickness evenness of the print is determined according to the first thickness,
Including：
The first thickness of the n measurement points is measured, obtains n first thickness value, by the maximum in the n first thickness values
Thickness evenness of the difference of value and minimum value as the print.
4. the valued methods of ultra-thin silica membrane print as described in claim 1, which is characterized in that thickness stability u3
Calculation formula be：
Wherein,Determining thickness average value is measured for ith,
5. the valued methods of ultra-thin silica membrane print as described in claim 1, which is characterized in that the thickness measure
Device is ellipsometer；
The partial uncertainty for determining the measurer for thickness and introducing, including：
Build silica-film thickness and ellipse drift angle and the database of the correspondence of phase difference；
Using j-th of measurer for thickness duplicate measurements measurement point k times, the k groups angle of polarization and phase difference are obtained, according to described
The k groups angle of polarization and phase difference build the normal distribution curve about the angle of polarization and the normal distribution curve about phase difference respectively；
H groups first are chosen from the normal distribution curve about the angle of polarization and the normal distribution curve about phase difference
The angle of polarization and first phase difference, and h third thickness is obtained with the database matching, calculate the standard deviation of the third thickness
The partial uncertainty introduced as the measurer for thickness；
Wherein, h and k is the positive integer more than 1.
6. the valued methods of ultra-thin silica membrane print as claimed in claim 5, which is characterized in that the structure dioxy
SiClx film thickness and ellipse drift angle and the database of the correspondence of phase difference, including：
Build structural model and dispersive model；Wherein, silica membrane of the structural model for silicon substrate and silicon substrate upper surface,
Set dispersion parameters, the dispersion parameters of silicon, lambda1-wavelength and the incident angle of silica；
According to the structural model and dispersive model structure silica-film thickness and the function of the angle of polarization and phase difference relationship；
Wherein, silica-film thickness and the function of the angle of polarization and phase difference relationship are obtained according to the following formula,
ρ is the elliptic function of silica membrane,For the amplitude reflectance in p-polarization direction,Amplitude for s polarization directions
Reflectance factor, rpThe mould of amplitude reflectance for p-polarization direction, rsThe mould of amplitude reflectance for s polarization directions,For
P-polarization phase,For s polarization phases, Ψ is the angle of polarization, and Δ is phase difference, r1sFor air and the interface of silica membrane
S directions polarized component fresnel reflection coefficient, r2sS directions polarized component for silica membrane and the interface of substrate is luxuriant and rich with fragrance
Alunite ear reflex coefficient, δ1To be tested the phase thickness of film layer, n0For air refraction, θ0For incident angle, n1It is thin for silica
Film refractive index, θ1For the incidence angle in silica membrane, n2For refractive index of substrate, θ2For refraction angle in substrate, r1pFor interface 1
P directions polarized component fresnel reflection coefficient, r2pFor the p directions polarized component fresnel reflection coefficient at interface 2, d1For dioxy
SiClx film thickness, λ lambda1-wavelengths；
According to the function, silica membrane and the angle of polarization and the correspondence of phase difference that thickness is 0 to 10 nanometer are determined.
7. the valued methods of ultra-thin silica membrane print as claimed in claim 5, which is characterized in that described from the pass
First angle of polarization of h groups and first is chosen in the normal distribution curve and the normal distribution curve about phase difference of the angle of polarization
Phase difference, and h third thickness is obtained with the database matching, including：
1 first angle of polarization is chosen from the normal distribution curve about the angle of polarization, from the normal state about phase difference
1 first phase difference is chosen in distribution curve；
Using method of seeking all over, first angle of polarization and the first phase difference and each group of second angle of polarization in database are calculated
With the evaluation function value of second phase difference, wherein, first angle of polarization and the first phase difference and the jth group in database
The evaluation function of second angle of polarization and second phase difference is：
For the value of j-th of evaluation function, ΨjFor the value of second angle of polarization of jth group in database, ΔjFor in database
The value of jth group second phase difference, ΨexpThe value of first angle of polarization for selection, ΔexpThe value of first phase difference for selection；
Choose second angle of polarization for making the evaluation function value minimum and the corresponding silica-film thickness of second phase difference
As third thickness；
It repeats to choose 1 first angle of polarization from the normal distribution curve about the angle of polarization, from described about phase difference
The step of 1 first phase difference is chosen in normal distribution curve, until obtaining h third thickness.
8. the valued methods of ultra-thin silica membrane print as described in claim 1, which is characterized in that cleaning substrate
It is cleaned in liquid, removes the impurity of the substrate surface, including：
The substrate is put into the first cleaning solution that temperature is 80 DEG C to 90 DEG C and is cleaned 10 minutes to 15 minutes；Wherein, it is described
First cleaning solution is the mixed solution of distilled water, ammonium hydroxide and hydrogen peroxide, and the volume ratio of distilled water, ammonium hydroxide and hydrogen peroxide is 4:
1:1；
By the substrate distilled water flushing to neutrality；
The substrate is cleaned 2 minutes to 5 minutes in a solution of hydrofluoric acid；
By the substrate distilled water flushing to neutrality；
The substrate is put into temperature to be cleaned 10 minutes to 15 minutes in 80 DEG C to 90 DEG C second cleaning solutions；Wherein, described
Two cleaning solutions are the mixed solution of distilled water, hydrochloric acid and hydrogen peroxide, and the volume ratio of distilled water, hydrochloric acid and hydrogen peroxide is 4:1:
1；
By the substrate distilled water flushing to neutrality；
The substrate is dried up with nitrogen.
9. such as the valued methods of the ultra-thin silica membrane print of claim 1 to 8 any one of them, which is characterized in that institute
The thickness for stating silica membrane is 2 nanometers to 5 nanometers.
10. a kind of preparation method of ultra-thin silica membrane print, which is characterized in that including：
Substrate in cleaning solution is cleaned, removes the impurity of the substrate surface；
Pass through the upper surface silicon dioxide thin film growth of the substrate of rapid thermal oxidation process after cleaning, the silica
The thickness of film is less than 10 nanometers.
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