CN106595501A - Method of measuring thickness or uniformity of optical thin film - Google Patents
Method of measuring thickness or uniformity of optical thin film Download PDFInfo
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- CN106595501A CN106595501A CN201611058937.XA CN201611058937A CN106595501A CN 106595501 A CN106595501 A CN 106595501A CN 201611058937 A CN201611058937 A CN 201611058937A CN 106595501 A CN106595501 A CN 106595501A
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- light
- thin film
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- optical
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Classifications
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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
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
Abstract
The invention discloses a method of measuring the thickness and the uniformity of a thin film by adopting a dual-wavelength method. The method comprises steps: first light and second light are provided, wherein the wavelength of the first light and the wavelength of the second light are different; the first light and the second light irradiate the optical thin film at a preset incident angle; the first reflectivity of the optical thin film towards the first light and the second reflectivity of the optical thin film towards the second light are acquired; and the optical features of the optical thin film are combined to calculate the thickness value of the optical thin film. The reflectivity values of the two wavelengths are used for expanding the thin film thickness measurement range, the repeated solution problem after solution in a single wavelength method is solved, the method can also realize uniformity test through expanding a light beam, and the optical thin film thickness measurement method of the invention has the advantages of being simple, effective, economic and practical, and applicable to industrial batch production.
Description
Technical field
The present invention relates to optical film thickness and uniformity measurement field, and in particular to one kind measures light using double-wavelength method
Learn film thickness and uniformity.
Background technology
The measurement of optical film thickness is one of very universal and important technical method of field of film preparation, common skill
Art includes step instrument, spectrometer, ellipsometer etc..Wherein, step instrument is a kind of contact mechanical meaurement, by Mechanical course precision
Affect, the sample of the hundreds of nanometer of general measure to tens microns, but its test process needs sample to there is " step ", i.e. sample
By cover film to the transitional region without cover film, institute is in this way unsatisfactory when batch is used.Spectrometer with it is ellipse
Instrument partially is measuring method.Spectrometer, in the response of different-waveband, is calculated using sample with reference to the dispersion curve of sample
To film thickness；Ellipsometer utilizes response of the sample to polarised light, and with reference to the optical property of sample film thickness is calculated.Light
The common advantage of spectrometer and ellipsometer is to use contactless measurement, on sample almost without impact, while both are by multiple
Miscellaneous iterative process, can reach high certainty of measurement.But in terms of applicability, both are required to the instrument of costliness
The calculating process of equipment and complexity, is not particularly suited for mass production.
In production field, the measurement of film thickness is also often using the measuring method of Single wavelength.By detecting sample to single
The response of wavelength, with reference to refractive index of the sample in this wavelength film thickness can be calculated, and the method greatly simplify measurement
Equipment and the demand of calculating.But, according to the correlation theory of film, the result of calculation of single wavelength measurement film thickness should be had
Infinite multiple solutions of some cycles.In actual production, utilization scope constraint has obtained a relatively simple result, but such
So that the method receives certain measurement range restriction.
In sum, a kind of simple and convenient optical film thickness measuring method is very necessary.
The content of the invention
The technical problem to be solved in the present invention is to provide a kind of measuring method and light of simple and convenient optical film thickness
Learn the measuring method of uniformity of film.
To solve above-mentioned technical problem, the present invention provides a kind of measuring method of optical film thickness, including：Step one：
The first light and the second light are provided, the wavelength of first light is differed with the wavelength of second light；Step 2：Will
First light and second light irradiate the optical thin film with default incidence angle；The optical thin film is obtained to institute
State the second reflectivity of first reflectivity and the optical thin film of the first light to second light；Step 3：With reference to institute
The optical characteristics for stating optical thin film calculates the thickness value for obtaining the optical thin film.
Preferably, the wavelength of first light is 300 nanometers, and the wavelength of the second light is 500 nanometers.
Preferably, the optical characteristics is the refractive index of the optical thin film.
Preferably, the refractive index of the optical thin film is obtained by spectrometer or ellipsometer measurement.
Preferably, the optical film thickness is obtained by reflectivity of optical thin film formula proving.
Preferably, the reflectivity of optical thin film computing formula isWhereind1For film thickness；η during p-polarization statei=ni/cos
θi, i=0,1,2；η during s polarization statesi=nicosθi, i=0,1,2；niFor refractive index, θiFor incidence angle.
Preferably, the number of degrees of the incidence angle are 8 degree.
The present invention also provides a kind of measuring method of optical thin film uniformity, including：Step one：First light and are provided
Two light, the wavelength of first light is differed with the wavelength of second light；Step 2：By first light and
Two light expand into hot spot；Step 3：First light and second light are irradiated into the light with default incidence angle
Learn film；The optical thin film is obtained to first reflected signal and the optical thin film of first light to second light
Second reflected signal of line；Step 4：The uniformity of performance optical thin film is returned according to reflected signal distribution.
The present invention is using dual-wavelength measurement optical film thickness or uniformity, and this measuring method is not only simple effective, and
It is economical and practical, it is adaptable to industrial mass manufacture；The present invention adopts dual-wavelength measurement optical film thickness or uniformity, due to being not required to
Utilization scope is wanted to constrain, measurement range is wider compared with unicast regular way.
Description of the drawings
With reference to the accompanying drawings and detailed description the present invention is further detailed explanation.
Fig. 1 is the flow chart measured to film thickness of one embodiment of the present invention.
Fig. 2 is the schematic diagram of reflectivity of the optical thin film of the present invention under two wavelength of 300nm and 500nm.
Fig. 3 is the flow chart measured to uniformity of film of one embodiment of the present invention.
Specific embodiment
The specific embodiment of the present invention is described in detail below in conjunction with accompanying drawing.It should be appreciated that this place is retouched
The specific embodiment stated is merely to illustrate and explains the present invention, is not limited to the present invention.
As shown in figure 1, being included according to the method for measuring film thickness of one embodiment of the present invention：
Step S11：First light A1 and the second light A2 is provided.Wherein, the wavelength of the first light A1 and the second light A2
Wavelength differ.In the embodiment of concrete measurement, the wavelength of the first light A1 is 300nm, and the wavelength of the second light is
500nm.Certainly, the wavelength of the first light A1 and the second light A2 can also choose other values, and concrete wavelength value can be according to required survey
Depending on the optical thin film type of amount or thickness.
Step S12：First light A1 and the second light A2 are exposed to into optical thin film with default incidence angle；Obtain described
Second reflectivity of the optical thin film to first reflectivity and the optical thin film of first light to second light.The
The incidence angle of one light A1 is equal to the incidence angle of the second light A2, and in specific embodiment, incidence angle can be for 0 ° to 90 ° arbitrarily
Value.
Step S13：The thickness value of the acquisition optical thin film is calculated with reference to the optical characteristics of the optical thin film.It is optically thin
The optical characteristics of film refers to the refractive index of optical thin film, can accurately be drawn by means such as spectrometer, ellipsometers.
The calculating derivation of measurement film thickness is introduced in detail below.In this embodiment, the wavelength of the first light A1
For 300nm and the second light A2 wavelength be 500nm, certain transparent optical film being radiated at 8 ° of incidence angle on Si pieces.
Reflectivity formula proving dependent equation using optical thin film is as follows：
The feature matrix of film is as shown in Equation 1：
The reflectivity of film can be derived by by formula 1, it is concrete as shown in Equation 2：
Wherein：
ηi=ni/cosθi, i=0,1,2, p-polarization state
ηi=nicosθi, i=0,1,2, s polarization states
d1It is film thickness；θiIt is incidence angle；niIt is the refractive index of material, for its refraction of certain optical thin film described in this example
Rate n1For arithmetic number, and refractive index n of substrate Si2For plural number, then η1For arithmetic number, and η2For plural number；It is public by relative index of refraction
Formula, obtains formula 3：
n0sinθ0=n1sinθ1=n2sinθ2(formula 3)
Such that it is able to formula 2 is derived as into formula 4
Wherein
This means that reflectivity is the periodic function of film thickness, it is therefore desirable to which two wavelength are calculating film thickness.
The optical property of certain optical thin film described in this example is calculated by ellipsometer measurement, and occurrence is as shown in table 1：
The dispersion relation of table 1 certain optical thin film
According to the parameter value in table 1, each parameter in formula 4 is thus obtained, concrete numerical value is as shown in table 2.
The value of each parameter in the formula 4 of table 2
Based on the numerical value listed by table 2, the reflectivity of the optical thin film and the corresponding relation of thickness can be drawn, it is concrete to close
System such as Fig. 2.Shown according to Fig. 2 contents, the relation waveform of reflectivity and optical film thickness is in substantially sinusoidal waveform, different wave length
Light it is different to the reflectivity of same thickness thin film.
The optical thin film is separately surveyed in the case where 300nm and two wavelength of 500nm are 8 ° in incidence angle, the sample it is anti-
Radiance rate value is as shown in table 3
The reflectivity of the sample of table 3
| Sample | 300nm reflectivity (%) | 500nm reflectivity (%) |
| 1# | 41.892 | 22.420 |
| 2# | 38.870 | 24.782 |
| 3# | 38.729 | 24.987 |
| 4# | 39.576 | 23.864 |
" the double-wavelength method measurement that double-wavelength method survey calculation obtains the film thickness such as table 4 of each sample is lifted by the application
As a result (nm) " shown in field, " the ellipsometer measurement result of the film thickness such as table 4 of the same sample accurately measured by ellipsometer
(nm) " shown in field.
The thickness of table 4 certain film
Double-wavelength method measurement result and the relative deviation data display of ellipsometer measurement result, are surveyed by double-wavelength method in table 4
The film thickness that amount is obtained is less with the film thickness error coefficient of ellipsometer measurement, thick by dual-wavelength measurement film so as to understand
The result of calculation that the method for degree is obtained is effective and believable.
The method of above-mentioned dual-wavelength measurement film thickness, can be extended to measure the uniformity of film.Specific flow process
Step is as shown in Figure 3.
Step S21：First light A1 and the second light A2 is provided.Wherein, the wavelength of the first light A1 and the second light A2
Wavelength differ.In the embodiment of concrete measurement, the wavelength of the first light A1 is 300nm, and the wavelength of the second light is
500nm.Certainly, the wavelength of the first light A1 and the second light A2 can also choose other values, and concrete wavelength value can be according to required survey
Depending on the optical thin film type of amount or thickness.
Step S22：The first light A1 and the second light A2 are expanded into into hot spot；
Step S23：First light A1 and the second light A2 are exposed to into optical thin film with default incidence angle；Obtain described
Second reflection letter of the optical thin film to first reflected signal and the optical thin film of first light to second light
Number.
Step S24：The uniformity of performance optical thin film is returned according to reflected signal distribution.
In step s 24, the method for film thickness is measured to each picture in reflected signal using above-mentioned double-wavelength method
Vegetarian refreshments carries out THICKNESS CALCULATION, then compares the film thickness of all pixels point in reflected signal, so as to obtain the optical thin film
Uniformity.
In specific implementation process, the first light and the second light are formed into the light with specific dimensions respectively through expanding
Spot, the such as round hot spot of a diameter of 100mm；By the light for expanding into hot spot with predetermined incidence angle irradiation optical thin film；Receive
To the reflected signal produced by light, reflected signal is specially the result of intensity distribution to optical thin film；According to above-mentioned calculating optical
The calculating derivation method of film thickness is calculated each pixel in reflected signal, is existed so as to obtain optical thin film
Uniformity in the range of 100mm.
Claims (8)
1. a kind of measuring method of optical film thickness, it is characterised in that include：
Step one：There is provided the first light and the second light, the wavelength of the wavelength of first light and second light not phase
Together；
Step 2：First light and second light are irradiated into the optical thin film with default incidence angle；Obtain institute
State second reflectivity of the optical thin film to first reflectivity and the optical thin film of first light to second light；
Step 3：The thickness value of the acquisition optical thin film is calculated with reference to the optical characteristics of the optical thin film.
2. the measuring method of a kind of optical film thickness according to claim 1, it is characterised in that first light
Wavelength is 300 nanometers, and the wavelength of second light is 500 nanometers.
3. the measuring method of a kind of optical film thickness according to claim 1, it is characterised in that the optical characteristics is
The refractive index of the optical thin film.
4. the measuring method of a kind of optical film thickness according to claim 3, it is characterised in that the optical thin film
Refractive index is obtained by spectrometer or ellipsometer measurement.
5. the measuring method of a kind of optical film thickness according to claim 3, it is characterised in that the optical thin film
Thickness is obtained by reflectivity of optical thin film formula proving.
6. a kind of optical film thickness measuring method according to claim 5, the reflectivity of optical thin film computing formula isWherein d1For
Film thickness；η during p-polarization statei=ni/cosθi, i=0,1,2；η during s polarization statesi=nicosθi, i=0,1,2；niFor refraction
Rate, θiFor incidence angle.
7. a kind of measuring method of optical film thickness according to claim 1, it is characterised in that the degree of the incidence angle
Number is 8 degree.
8. a kind of measuring method of optical thin film uniformity, it is characterised in that include：
Step one：There is provided the first light and the second light, the wavelength of the wavelength of first light and second light not phase
Together；
Step 2：First light and the second light are expanded into into hot spot；
Step 3：First light and second light are irradiated into the optical thin film with default incidence angle；Obtain institute
State optical thin film to reflect the second of second light first reflected signal and the optical thin film of first light
Signal；
Step 4：The uniformity of performance optical thin film is returned according to reflected signal distribution.
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| CN201611058937.XA CN106595501A (en) | 2016-11-25 | 2016-11-25 | Method of measuring thickness or uniformity of optical thin film |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107560557A (en) * | 2017-08-31 | 2018-01-09 | 长江存储科技有限责任公司 | A kind of method and device for measuring deep hole wall films thickness |
| CN109141259A (en) * | 2018-08-06 | 2019-01-04 | 华中科技大学 | A kind of optical constant of thin absorbing film and the measuring device and method of thickness |
| CN109470154A (en) * | 2018-12-26 | 2019-03-15 | 武汉颐光科技有限公司 | Value measurement method at the beginning of a kind of film thickness suitable for spectroscopic ellipsometers |
| CN109883553A (en) * | 2019-03-14 | 2019-06-14 | 上海精测半导体技术有限公司 | A kind of polarimeter |
| CN111417833A (en) * | 2018-01-09 | 2020-07-14 | 浜松光子学株式会社 | Film thickness measuring device, film thickness measuring method, film thickness measuring program, and storage medium storing film thickness measuring program |
| CN111593308A (en) * | 2019-02-20 | 2020-08-28 | 咸阳彩虹光电科技有限公司 | Manufacturing method of planar magnetic plate for improving uniformity of metal film production |
| CN111912785A (en) * | 2020-07-22 | 2020-11-10 | 深圳信息职业技术学院 | Optical constant measuring method and optical constant measuring equipment |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107560557A (en) * | 2017-08-31 | 2018-01-09 | 长江存储科技有限责任公司 | A kind of method and device for measuring deep hole wall films thickness |
| CN107560557B (en) * | 2017-08-31 | 2019-08-06 | 长江存储科技有限责任公司 | A kind of method and device measuring deep hole wall films thickness |
| CN111417833A (en) * | 2018-01-09 | 2020-07-14 | 浜松光子学株式会社 | Film thickness measuring device, film thickness measuring method, film thickness measuring program, and storage medium storing film thickness measuring program |
| US11280604B2 (en) | 2018-01-09 | 2022-03-22 | Hamamatsu Photonics K.K. | Film thickness measurement device, film thickness measurement method, film thickness measurement program, and recording medium for recording film thickness measurement program |
| CN111417833B (en) * | 2018-01-09 | 2022-12-06 | 浜松光子学株式会社 | Film thickness measuring device, film thickness measuring method, film thickness measuring program, and storage medium storing film thickness measuring program |
| CN109141259A (en) * | 2018-08-06 | 2019-01-04 | 华中科技大学 | A kind of optical constant of thin absorbing film and the measuring device and method of thickness |
| CN109141259B (en) * | 2018-08-06 | 2020-06-30 | 华中科技大学 | Device and method for measuring optical constant and thickness of thin absorption film |
| CN109470154A (en) * | 2018-12-26 | 2019-03-15 | 武汉颐光科技有限公司 | Value measurement method at the beginning of a kind of film thickness suitable for spectroscopic ellipsometers |
| CN111593308A (en) * | 2019-02-20 | 2020-08-28 | 咸阳彩虹光电科技有限公司 | Manufacturing method of planar magnetic plate for improving uniformity of metal film production |
| CN109883553A (en) * | 2019-03-14 | 2019-06-14 | 上海精测半导体技术有限公司 | A kind of polarimeter |
| CN111912785A (en) * | 2020-07-22 | 2020-11-10 | 深圳信息职业技术学院 | Optical constant measuring method and optical constant measuring equipment |
| CN111912785B (en) * | 2020-07-22 | 2023-06-23 | 深圳信息职业技术学院 | Optical constant measuring method and optical constant measuring equipment |
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Application publication date: 20170426 |