CN1177078C - Method for preparing nano membrane device - Google Patents

Abstract

The present invention relates to a method for making a thin-film device with nanometer properties. In the method, a high-speed dynamic spectrometer is adopted so as to rapidly detect and analyze the variation of the spectral properties of the device during the preparation process according to a technique in real time. In an infrared communication waveband of 1400 to 1600 nm, spectral resolution which is less than or equal to 1 second and is better than of 0.1 nm is obtained, the relation between parameters changed according to technique conditions, such as the refractivity, the transmitting bandwidth, the reflecting bandwidth, the spectral bandwidth, the line shape, the layer thickness, etc. of each film layer of the device can be obtained. Thereby, factors which affect the properties of the thin-film device can be accurately controlled and adjusted in real time. A system has high reliability for long-time work and the excellent repeatability of the spectral data of the nanometer device.

Description

A kind of preparation method of nano membrane device

Technical field

The invention belongs to optical electron device technology field, be specially a kind of preparation method of nano membrane device.

Background technology

Multilayer film with nanostructure and nano-meter characteristic have important application in high-tech area, it is characterized in that the complex structure of film, and the individual layer thickness is tens to the hundreds of nanometer range, form to tunic structures up to a hundred by tens.This device becomes the super arrowband of high-performance dielectric filter sheet and obtains to use in the dense wave division multipurpose optical communication system, also can obtain important application in fields such as space flight and national defence.The high performance thin film device of this and approximation theory design limit, in its preparation process, be difficult to its preparation process and nano spectral characteristic thereof accurately be controlled by traditional method, it is the component that every tunic accumulates in technology, variations in refractive index and the generation of geometric thickness error can not be repaired after technology finishes to device architecture and Effect on Performance, and must in preparation process, carry out sign on the throne and adjustment to its characteristic and corresponding characteristic parameter, comprise the spectral response curve of each tunic is analyzed, pinpoint the problems, in time in the material preparation process, correct and solve.This is the essence progress of sub-thin-film device preparation principle of modern nano photoelectric and technology, is decision and the key that influences device performance and quality.

In the world advanced nano-photon device preparation system (as the film preparing system of German Leybold electron beam evaporation), adopted optical detective technology on the throne, because of being difficult for taking into account the contradiction between wide spectral detection, speed and the resolving power, only adopted static optical wavelength T _xThe method of measuring is characterized by:

Film preparation → in real time static single wavelength optical detects T _x→ technology controlling and process

This has had marked improvement technically, but because of can't in the very short time of film growth, realizing spectral response curve is carried out high speed and high-precision sweep measurement, can't in certain bandwidth range, carry out in real time full spectral detection and analysis, comprise and to do quantitatively characterizing and modification to the mobile of spectrum overall picture characteristic and spectral line in the multilayer film process of growth, thereby the quality factor of device is still had a significant impact.For example, fixing a certain optical monitoring wavelength by measuring this wavelength place light intensity variation relation of (thickness) in time, is tried to achieve extreme value, determines the value of light refractive index and thickness in real time.Because the spectrum bandpass characteristics that multi-cavity multilayer film device architecture has intimate square type, the flat-top extreme value district that promptly has certain width, this brings difficulty for the static extreme value monitoring method of single wavelength, though can try to achieve light intensity variable quantity △ I is zero extreme value district to time △ t derivative, but be difficult to accurately judge the extreme value central position, influenced the accurate of device quality and high-level efficiency control.In the high quality nano multilayer film preparation of devices system of present limited type in the world, be subjected to optical principle and technology limitation, all adopt static wavelength optical detecting method, and can't carry out online in real time fast monitored and sign to the spectrum kinetic characteristic in the device preparation process, limited the further raising of device performance.

Summary of the invention

The objective of the invention is to propose a kind of can Real-time and Dynamic Detection device spectral response curve in the thin-film device preparation process, and to its nano thin-film preparation of devices method of controlling.

The nano thin-film preparation of devices method that the inventive method proposes is the improvement to aforesaid method, and its formula is:

Film preparation → Real-time and Dynamic spectral detection T _x→ technology controlling and process

Concrete steps are as follows: under the vacuum condition of film preparation, adopt the vacuum stepper-motor, be placed on the top in the vacuum chamber, motor shaft is processed to hollow, allows detection light pass from axle; The transparent substrate of support film device is fixedly mounted on the motor shaft, and substrate surface is vertical with motor shaft, and promptly vertical with detection light, the rotation of built-in motor does not have influence to vacuum; Adopt segmentation step technology that rotating speed of motor is accurately controlled, make sample do at the uniform velocity rotation; Pure quartzy optical window is equipped with in the top of vacuum chamber and bottom, vacuum chamber is isolated, and allow detection light pass through; The thin film evaporation source places the bottom in the vacuum chamber.When evaporation source was worked, film began deposit on substrate.Survey light incides substrate sample from the bottom quartz window of vacuum chamber central authorities.Survey light by the sample transmission after, pass from the tubular shaft of motor, pass from the quartz window at vacuum chamber top.The dynamic spectrum analyser is installed in the outer top of vacuum chamber, spectrum from the sample outgoing is carried out rapid detection and analysis, data are reached Computer Analysis, obtain the abundant informations such as transmitted spectrum feature of film in the film preparation process in real time, and the working order of feedback control evaporation source, realize the thickness of multilayer film and the accurate control of characteristic.

In the aforesaid method, the spectrum analyzer of use can adopt the high speed dynamic spectrum analyser of no mechanical displacement.

The present invention adopts Real-time and Dynamic spectrum T in the preparation process of multi-layer nano film _xDetection method.This is a kind of contactless nondestructive highly sensitive film preparation characterizing method, promptly in the cycle of film preparation, adopt high speed and high-resolution spectral method of detection, spectrum line style, light intensity, spectral distribution characteristic and centre wavelength position to the thin-film device in the preparation process are analyzed real-time and are adjusted with the parameter of technique change, can obtain the complete physical optical characteristics of thin-film device in the preparation process in real time, reliably control its preparation characteristic.

Description of drawings

Fig. 1. a kind of preparation method's of nano-meter characteristic film synoptic diagram.The detection light that is sent by light source L enters thin-film device through quartz window and prepares in the vacuum chamber V.M is the high vacuum step motor of segmentation step control, and its axle is processed to hollow.The transparent substrate S that supports nano membrane device is installed on the motor drive shaft, is directly driven by motor.The S plane is vertical with motor drive shaft.Survey light by the transmission of S device after, pass the tubular shaft of motor, outgoing vacuum chamber V.The detection light of the entrained S of having device spectral response curve enters the high speed and the high resolution dynamic spectrum analyser MW of no mechanical displacement component, with≤1 second time and the spectral resolution that is better than 0.1nm, obtain the relation that parameters such as each thin-film refractive index of device, transmission, reflection, spectral bandwidth, linear and bed thickness change with processing condition such as temperature, growth velocity and components, and then feedback control multiple gun electron beam evaporation source S1 and S2, the factor that influences the thin-film device characteristic is carried out in real time accurately control and adjusted the high-quality preparation of realization nano thin-film device.

Embodiment

The bottleneck that under the restriction vacuum environment spectral response curve of thin-film device is carried out high speed detection is a traditional slow machinery Wavelength scanning device, be difficult to take into account simultaneously spectral width, spectral resolution and contradiction between speed, as adopt the conventional raster-scan spectrographic technique, be difficult in≤1 second time and in the 200nm spectral width, highly repeatedly spectroscopic data gathered and analyzed for a long time with spectral resolution and the high s/n ratio quality of 0.1nm.Simultaneously, also need the PROCESS COUPLING of high-speed light spectrum analysis is advanced in the high vacuum specimen preparation chamber.In order to overcome these gordian technique difficulties, in the method, monitoring will be adopted the high-speed light spectral analysis method of no any mechanical shift parts to nano thin-film preparation process characteristic,

The concrete formula of implementing is:

Light source → optical coupled → nano thin-film device prepares the characteristic present of vacuum chamber → film transmission or reflection → pass motor shaft → optical fiber → dynamic spectrum analyser → acquisition complete spectrum → computer data analysis → fast and assessment → film characteristics and quality are controlled in real time

In the film preparing system of multiple gun electron beam evaporation, set up quick real time spectrum Monitoring systems.At optical communicating waveband (1400-1600nm), produce continuous light by the high stable halogen tungsten lamp.Under the high vacuum condition of thin-film device preparation, adopt the high vacuum stepper-motor, be placed on the top in the vacuum chamber, motor shaft is a hollow, allows detection light therefrom pass.Transparent substrate is fixedly mounted on the motor shaft, and substrate surface is vertical with motor shaft, and is promptly vertical with detection light.Adopt the rotation mode of built-in motor that vacuum tightness is not had influence.Adopt segmentation step technology that rotating speed of motor is accurately controlled, allow sample do at the uniform velocity rotation with motor shaft.Pure quartzy optical window is equipped with in the top of vacuum chamber and bottom, plays vacuum insulation and allows the effect that light passes through of surveying.Multiple gun electron beam thin film evaporation source places the bottom in the vacuum chamber.When evaporation source was worked, film began deposit on substrate.Survey light incides substrate sample from the bottom quartz window of vacuum chamber central authorities.Survey light by the sample transmission after, pass the tubular shaft of motor, (also can be reflected by sample) passes from the quartz window at vacuum chamber top.The high-speed light spectrometer of no mechanical displacement is installed in the outer top of vacuum chamber.Survey light and enter spectroscopic analysis system by adjustable narrow meeting, spectrum from the sample outgoing is carried out rapid detection and analysis, data are reached Computer Analysis, obtain the abundant informations such as transmitted spectrum feature of film in the film preparation process in real time, and the working order of feedback control evaporation source, realize the thickness of multilayer film and the accurate control of characteristic.By the needs of using, survey light and also can enter from the top quartz window of vacuum chamber, pass from the bottom quartz window, and the high-speed light spectrometer that will not have a mechanical displacement places vacuum chamber bottom outward.

In the present embodiment, the high-speed light spectrometer that does not have a mechanical displacement can adopt multiple grating spectrograph imaging device (Chinese patent application number be 02260755.2), adopts optical fiber or lens will survey the spectroscopic analysis system that optically-coupled advances to have adjustable slit.This spectroscopic analysis system adopts the optical system of 500mm focal length and the grating of n piece (as n=5) 600 lines/mm (also can choose other separation density gratings and more raster count by application requiring), every block of grating is of a size of 20 * 100mm, grating is parallel with minor face, and the effective area of raster that is combined into is 100 * 100mm.With n piece grating along and the vertical y direction of the plane of incidence arrange, adjust each grating position angle, make that in same diffraction subtended angle from the Wavelength distribution difference of the wavelength zone of each sub-gratings outgoing, but the wavelength tandem array constitutes complete wavelength zone.The dispersion property of this spectrograph are about 3.0nm/mm.At near infrared light communication 1400-1600nm wavelength zone, the coverage area that its all-wave is long is about 200nm.Focal plane position at the detector place covers size along the total detection of Wavelength distribution direction (x direction) and is about 60.0mm.Adopt n linear array detector, each detector covers 12mm spectrographic detection district (being equivalent to the 40nm wavelength zone) approximately.Adopt the InGaAs linear array infrared eye of 512 pixels, the wavelength workspace is 700-1700nm, and each pixel is of a size of 0.024 (H) * 0.080 (V) mm, the test surface that constitutes is about 12.3 (H) * 0.08 (V) mm, wherein, H is expressed as horizontal x direction, and V is vertical y direction.

Therefore, accurately regulate the position angle of every block of grating, make its spectrographic in identical diffraction subtended angle be respectively 1400-1440nm, 1440-1480nm, 1480-1520nm, 1520-1560nm, 1560-1600nm, promptly the work spectral region of every sub-gratings are 40 nanometers, with every group be InGaAs linear array detector (the n group altogether of 512 pixels, arrange along the vertical y direction of the plane of incidence) corresponding, the pairing wavelength resolution of each pixel is 0.08nm.

Adopt f ₁The cylindrical mirror of=500mm focal length is assembled along the x direction spectrum.f ₁Cylindrical mirror is of a size of 100 * 100mm, receives the parallel diffraction light from grating, with focal imaging behind the spectral reflectance on the focal plane of detector.Adopt n f ₂The sub-cylindrical mirror of=250mm focal length, size all are 20 * 100mm, and focusing surface is a minor face.f ₂Mirror places f along the minor face parallel arranged with them ₁In the middle of the position between mirror and detector light path, its effect is that light intensity to each sub-spectral region is along the y directional focusing.Regulate each f ₂The position angle of mirror focuses on the light intensity of n sub-spectral region respectively and to have on n the linear array detector that certain intervals arranges.

The standard infrared communication optically filtering sheet that adopts the standard gas line spectrum source or have a 0.04-0.08nm bandwidth carries out precise calibration to each detector pixel with the distribution of wavelength, fits to calibration curve, and the input computer is done the quantitative analysis of spectroscopic data and used.

Because the mechanical shift of no any optics in full spectral measurement can be realized spectrographic high speed and high resolving power measurement.Spectral detection speed only is subjected to the linear array of linear array detector response speed and subsequent data transmissions and processing speed.Full spectral measurement speed with 14-16bit Data Dynamic scope can be faster than 0.01 second, the spectrographic highest resolution can reach 0.08nm, can satisfy the requirement that the variation of right≤spectral response curve that the 1.0nm change in film thickness causes in≤1 second time preparation process is measured in real time and analyzed, be implemented in≤in 0.1 second time, obtain the data that the optical information relevant with the material growth technique changes, comprise specific refractory power, transmission, reflection, spectral bandwidth, parameters such as linear and bed thickness are with temperature, the relation that processing condition such as growth velocity and component change is carried out in real time accurately control and adjustment to the factor that influences the thin-film device characteristic.Owing to exempted the mechanical shift parts, system has the high reliability that works long hours and fabulous spectroscopic data repeatability.

Claims (3)

1, a kind of preparation method of nano membrane device, it is characterized in that under the vacuum condition of film preparation, adopt the vacuum stepper-motor, be placed on the top in the vacuum chamber, motor shaft is processed to hollow, the transparent substrate of support film device is fixedly mounted on the motor shaft, and substrate surface is vertical with motor shaft; Adopt segmentation step technology that rotating speed of motor is accurately controlled, make sample do at the uniform velocity rotation; Pure quartzy optical window is equipped with in the top of vacuum chamber and bottom, vacuum chamber is isolated, and allow detection light pass through; The thin film evaporation source places the bottom in the vacuum chamber; Survey light by the sample transmission after, pass from the tubular shaft of motor, pass from the quartz window at vacuum chamber top; The dynamic spectrum analyser is installed in the outer top of vacuum chamber, spectrum from the sample outgoing is carried out rapid detection and analysis, data are reached Computer Analysis, obtain the transmitted spectrum characteristic information of film in the film preparation process in real time, and the working order of feedback control evaporation source, realize the thickness of multilayer film and the accurate control of characteristic.

2, preparation method according to claim 1 is characterized in that spectrum analyzer adopts the high speed dynamic spectrum analyser of no mechanical displacement.

3, preparation method according to claim 1 and 2 is characterized in that surveying light and also can enter from the top quartz window of vacuum chamber, pass from the bottom quartz window, and the high-speed light spectrometer that will not have a mechanical displacement places the outer bottom of vacuum chamber.

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