CN1922115A - Synthetic silica glass optical material and method of producing it - Google Patents

Abstract

Disclosed is a synthetic silica glass optical material having high resistance to optical damage by ultraviolet radiation in the ultraviolet wavelength range, particularly in the wavelength less than about 250 nm and particularly, exhibiting a low laser induced wavefront distortion; specifically a laser induced wavefront distortion, measured at 633nm, of between about -1.0 and 1.0 nm/cm when subjected to 10 billion pulses of a laser operating at approximately 193 nm and at a fluence of approximately 70 J/cm<2>. The synthetic silica glass optical material of the present invention comprises OH concentration levels less than about 600ppm, preferably less than 200ppm, and H2 concentration levels less than about 5.0x10<17> molecules/cm<3>, and preferably less than about 2.0x10<17> molecules/cm<3> . A method of producing a synthetic silica glass optical material is also claimed.

Description

Synthetic silica glass optical material and preparation method thereof

Cross-reference to related applications

The present invention requires the U.S. Provisional Patent Application series number the 60/547th of " the SYNTHETIC SILICA GLASSOPTICAL HAVING HIGH RESISTANCE TO LASER INDUCED DAMAGE " by name of submission on February 23rd, 2004, the U.S. Provisional Patent Application series number the 60/640th of " the SYNTHETIC SILICA GLASS OPTICAL HAVING HIGH RESISTANCE TOLASER INDUCED DAMAGE " by name that submits in No. 304 and on December 31st, 2004, No. 777 right of priority, the content of these patents is incorporated by reference into this paper in full.

Invention field

The present invention relates to high purity synthetic silica material or fused silica material and preparation method thereof.Specifically, the present invention relates to laser induced infringement is had high purity synthetic silica optical material or the fused silica optical material and the optics of the tolerance of raising.The present invention for example can be used for making high purity synthetic silica material or the fused silica material that is used at the optics of extreme ultraviolet and vacuum ultraviolet operation effectively.

Background of invention

In commercial actual production, the fused silica optics of lens, prism, spectral filter, photomask, reverberator, on-gauge plate and window and so on is normally made by the fused silica bulk sheet material (bulk piece) that makes in large-scale manufacturing stove.The fused silica bulk sheet material of making in large-scale manufacturing stove is called as crystal block (boule) or crystal ingot in this area.Cut out blank from crystal block or crystal ingot, use following manufacturing step to produce final optics by the glass blank, described step can include, but are not limited to the sheet glass that is made by blank is cut, polishes and/or applies.Many such opticses are used in the various device, and these equipment are used to be exposed in the environment of the UV-light (for example swashing basic laser beam or other UV laser beam) that wavelength is approximately equal to or less than 360 nanometers.These opticses are installed in the various device, comprise the photoetching laser explosure equipment that is used for making the height unicircuit, laser producing apparatus, medical facilities, nucleosynthesis equipment or use other equipment of high-power UV laser beam.

Along with the energy of laser and the increase of pulse-repetition, the optics that uses with these laser apparatus combinations is exposed under the laser radiation of increase.Because the fused silica material has splendid optical property and to the tolerance of laser induced infringement, so the fused silica parts preferably are used for making these based on the optics in the optical system of laser widely.

Laser technology has developed into shortwave high energy UV spectrum district, and its effect is to increase the light frequency (reducing wavelength) that laser apparatus produces.People's special concern be that short wavelength in the running of ultraviolet wavelength district and extreme ultraviolet (DUV) wavelength zone swashs base laser, its wavelength that is included in about 193 nanometers and 248 nanometers is the laser apparatus of running down.Swash the base laser system and in microlithography applications be very popular, the wavelength of shortening can improve unicircuit and the microchip linear density in making, thereby can make the circuit with the characteristic dimension that reduces.A direct physical result of shorter wavelength (upper frequency) is, because each the independent photon in the light beam has higher energy, so light beam has higher photon energy.In these sharp base laser systems, the fused silica Optical devices are exposed under the high-energy photon irradiation for a long time, make the optical property of optics reduce.

Known this laser induced performance reduction meeting causes negative impact by reducing transmittance, make the glass variable color, change specific refractory power, change density and increasing the absorbancy of glass to the optical property and the performance of fused silica Optical devices.In these years, people have proposed the optics infringement tolerance that many methods are improved fused silica glass.Recognize that gradually the high purity fused silica of methods such as electrofuse by flame hydrolysis, CVD soot remelting process, plasma CVD method, quartz crystal powder and additive method preparation is easy to be subjected to the laser infringement of various degree.

A kind of common suggestion is that the OH content in this glass is increased to very high level.For example, Escher, G.C. at KrF Laser Induced Color Centers In Commercial Fused Silicas, SPIE the 998th volume, Excimer Beam Applications, proved in the 30-37 page or leaf (1988) that the defective generating rate depends on fused silica OH content, the silicon-dioxide that therefore " wets " is KrF purposes preferable material.Specifically, they find that the silicon-dioxide of high OH content is higher than the silicon-dioxide of low OH content to the tolerance of infringement.

United States Patent (USP) the 5th, 086 has also disclosed for the 5th, 325, No. 230 with relevant United States Patent (USP) for No. 352, and opticglass depends on OH group content in the presence of hydrogen to the tolerance of optical property deterioration when being exposed to short wavelength's UV laser beam.Specifically, these reference explanations, the high-purity silicon dioxide glass with low OH content is very poor to the weather resistance that KrF swashs basic laser.Therefore, they propose OH content and are at least 50ppm.Similarly, Yamagata, S. at Improvement of Excimer Laser Durability ofSilica Glass, Transactions of the Materials Research Society of Japan, the 8th volume, disclosed in the 82-96 page or leaf (1992) at the high-purity silicon dioxide glass that is 750 ppm by weight with the sharp basic laser irradiation OH group content of KrF and (for example used the oxygen flame hydrolysis, by high purity silicon tetrachloride synthetic silica glass) time, dissolved hydrogen is to the influence of fluorescent emission behavior and transmissivity decline.

Other people have also proposed to improve the method for the optical durability of fused silica.Faile for example, S.P. and Roy, D.M. at Mechanism of Color Center Destruction in Hydrogen ImpregnatedRadiation Resistant Glasses, Materials Research Bull., the 5th volume, the glass that has disclosed in the 385-390 page or leaf (1970) with the hydrogen dipping tolerates the radiation that gamma-radiation causes easily.Japanese patent abstract 40-10228 has disclosed a kind of method, and this method will be heated to about 400-1000 ℃ by the quartz glass product of fusion preparation, in case the variable color owing to the influence of ionizing rays (Exposure to Sunlight) under hydrogenous atmosphere.Similarly, Japanese patent abstract 39-23850 has disclosed and can heat-treat under the oxygen atmosphere of same temperature ranges stated then by under 950-1400 ℃ hydrogen atmosphere glass being heat-treated, to improve the transmissivity of silica glass to UV-light.

Shelby, J.E. at Radiation Effects in Hydrogen-impregnated Vitreous Silica, J.Applied Physics, the 50th volume, the 5th phase, proposed the irradiation of the vitreous silica of hydrogen dipping has been suppressed the formation of optical defect in the 3702-06 page or leaf (1979), but the hydrogen dipping also can generate a large amount of bonded hydroxyls and hydride, and glass swelling or density are reduced.

Recently, United States Patent (USP) the 5th, 410, disclosed a kind of method that optical property descends that is used for preventing to cause for No. 428, this method adopts the complex combination of some treating processess and the composition of fused silica parts to control hydrogen concentration and the specific refractory power that reaches specific, thereby improve Ultra-Violet Laser is caused the tolerance that character descends.This patent proposes; under such uv irradiation; chemical bond in the fused silica reticulated structure between silicon and the oxygen can rupture usually, then with other structure recombine, makes the local density of fused silica target area increase and local indexes of refraction increases.

In the time of nearer, Araujo etc. have disclosed a kind of laser to 248 nano wave lengths up to 10 in No. the 5616th, 159, United States Patent (USP) ⁷Pulse (350 milli Jiao/centimetre ²/ pulse) infringement of optics under has very the high purity fused silica of height endurability and the method for making this glass.The compositions that the people disclosed such as Araujo comprise the OH of 50ppm at least, H ₂Concentration is greater than 1 * 10 ¹⁸Molecule/centimetre ³

Although aforesaid method can reduce the light absorption ratio of 215 nanometers and 260 nanometers effectively to small part, these methods are not all almost mentioned or are not mentioned fully the solution of long-term exposure in the compression or the optics infringement that expansion causes of the radiation initiation that swashs basic laser generation.Because semi-conductor industry depends on and swashs basic laser and material that can this energy of transmission is made integrated circuit (IC) chip and other products, and constantly developing towards reducing live width and reduce the direction that incident light must wavelength in should industry always, therefore need dwindle the incident light wavelength, cause the energy level of laser to raise, therefore strict more to the requirement of fused silica material.Therefore, people constantly need more improved fused silica glass, be thereby that the incident light energy is the fused silica material that inertia has higher tolerance to long-term exposure in the optics infringement in ultraviolet laser radiation following time as far as possible specifically, specifically, be that the optics infringement that the uv-radiation that long-term exposure produces in the sharp basic laser by 193 nanometers and 248 nanometers causes is had tolerance.

Therefore, the objective of the invention is to disclose a kind of method, this method is used for improving the tolerance that high purity fused silica glass is damaged the optics that is caused by laser induced compression or expansion in the use.

The invention summary

The present invention relates to synthetic silica glass optical material or fused silica glass optical material.In this article, term " synthetic silica glass optical material or fused silica glass optical material " be included in the fused silica crystal block of preparation in the process furnace or bulk sheet material, pre-type body, by the blank of crystal block or pre-type body cutting and the fused silica optics of making by synthetic fused silica blank.The manufacturing of fused silica optics can relate to following finishing step, includes but not limited to the fused silica glass sheet material is cut, grinds, polishes and/or applies.

According to one embodiment of the present invention, synthetic silica glass optical material is provided, these materials are that the optics infringement that causes less than the uv-radiation in 250 nanometer wavelength range approximately has very high tolerance to UV wavelength range specifically.When its be subjected to about 70 little Jiao/centimetre ²10,000,000,000 laser pulse effects of energy density, about 193 nanometers the time, record in 633 nanometers, by the wavefront distortion of laser induced this synthetic silica glass optical material be-1.0 to 1.0 nanometers/centimetre; Preferably-0.1 to 1.0 nanometers/centimetre.In another embodiment, when be subjected to about 40 little Jiao/centimetre ²Energy density, when being about 10,000,000,000 laser pulse effects of 193 nanometers, record in 633 nanometers, by the wavefront distortion of laser induced this synthetic silica glass optical material be about-0.5 to 0.5 nanometer/centimetre; Preferably be about-0.1 to 0.5 nanometer/centimetre.

In one embodiment of the present invention, the H of synthetic silica glass optical material of the present invention ₂Concentration is approximately less than 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is approximately less than 600ppm; Preferably H ₂Concentration is approximately less than 2.0 * 10 ¹⁷According to another embodiment, the H of used synthetic silica glass optical material ₂Concentration is about 0.1 to 2.0 * 10 ¹⁷Molecule/centimetre ³, its OH concentration is approximately less than 125ppm.The H of another embodiment of synthetic silica glass optical material ₂Concentration is about 0.4 to 1.0 * 10 ¹⁷Molecule/centimetre ³, its OH concentration is approximately less than 600ppm.

Can use synthetic silica glass optical material manufacturing of the present invention to be used for the lens combination of lithographic equipment, the degree owing to laser induced wavefront distortion in interior bonded consolidation of these lens combinations or the synthetic silica glass lens reduces.

Other advantages of the present invention will be listed in the following discussion.Be to be understood that above summary and following detailed description are exemplary, be used for further specifying the present invention according to desired content.

The accompanying drawing summary

Fig. 1 is the influence of display change OH concentration to the wavefront distortion of the laser induced synthetic silica optical material of about 193 nanometers;

Fig. 2 has a H that is lower than present detectability to a series of ₂When the silicon-dioxide optical material of content and various OH concentration applies about 193 nm radiations of various energy densities, the relation of wavefront distortion and laser pulse number;

Fig. 3 shows for many of the present invention and synthetic silica optical materials (three of the present invention and 1 comparison) relatively, the figure of the funtcional relationship of the laser pulse number of about 193 nanometers under wavefront distortion (recording in 633 nanometers) and the different-energy density;

Fig. 4 shows for many of the present invention and synthetic silica optical materials (six embodiments of the invention and three comparative examples) relatively, the figure of the funtcional relationship of the laser pulse number of about 193 nanometers under wavefront distortion (recording in 633 nanometers) and the different-energy density;

Fig. 5 shows many of the present invention and synthetic silica optical materials relatively, under the different-energy density of about 193 nanometers of wavelength, and the figure of the funtcional relationship of degree of birefringence and laser pulse number;

Fig. 6 is the synthetic silica optical material (identical six embodiment of the invention and three comparative examples being described in detail in detail with Fig. 4) that shows many of the present invention and comparisons, under the different-energy density of about 193 nanometers, the funtcional relationship of its wavefront distortion (recording) and laser pulse number in 193 nanometers.

Detailed Description Of The Invention

In the art, well-knownly be that synthetic fused silica is in the process of the laser that is exposed to high-energy-density or " compression " phenomenon can take place afterwards.This influence causes local density to increase, and specific refractory power is increased, thereby makes the optical property deterioration of optical element.In addition, knownly also opposite influence can take place, promptly when the optical quartz glass component exposure in the situation of laser with low energy densities and high impulse number.Observe expansion in these cases, also reduce simultaneously with specific refractory power.Do not consider the phenomenon that taken place, this laser infringement makes the optical property deterioration, thereby has limited the work-ing life of optical element.

The invention provides a kind of transmission peak wavelength that is used for and be equal to or less than the synthetic quartz glass optical material of the uv-radiation of 250 nanometers, that this material has is low/the laser induced degree of damage that reduces.Synthetic silica glass optical material of the present invention is made by the synthetic silica glass of ultra-high purity, has the composition of following special preparation, to show this optimized laser infringement tolerance.Specifically, the H of synthetic silica glass optical material of the present invention ₂Concentration is approximately less than 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is approximately less than 600ppm.But the preferred H of this synthetic silica glass ₂Concentration is approximately less than 2.0 * 10 ¹⁷Molecule/centimetre ³Synthetic silica glass optical material of the present invention is applied energy density be about 70 little Jiao/centimetre ², when pulse length is about 10,000,000,000 pulse lasers of 25-35 nanosecond/pulse, record in 633 nanometers, laser induced wavefront distortion (hereinafter being called LIWFD) be about-1.0 to 1.0 nanometers/centimetre, this has proved that synthetic silica glass optical material of the present invention increases the tolerance of laser infringement.Preferably, described synthetic silica glass optical material is applied energy density be about 70 little Jiao/centimetre ², wavelength be about 193 nanometers, pulse length be about 10,000,000,000 pulses of 25-35 nanosecond/pulse, more preferably 20,000,000,000 laser pulses the time, the LIWFD that this bill of material reveals be about-1.0 to 1 nanometer/centimetre.In another embodiment, described synthetic silica glass is applied energy density be about 40 little Jiao/centimetre ², wavelength is about 193 nanometers, when pulse length is about 10,000,000,000 laser pulses of 25-35 nanosecond, this glass the LIWFD that 633 nanometers record be about-0.5 to 0.5 nanometer/centimetre; Be more preferably-0.1 to 0.5 nanometer/centimetre.

In another preferred embodiment, the H of described synthetic silica glass optical material ₂Concentration is about 0.4 to 2.0 * 10 ¹⁷Molecule/centimetre ³, its OH concentration is more preferably 0.1-200ppm approximately less than 200ppm.

In another embodiment, the H of synthetic silica glass optical material ₂Concentration is about 0.1 to 1.0 * 10 ¹⁷Molecule/centimetre ³, its OH concentration is approximately less than 125ppm; Preferably be about 0.1-100ppm, be more preferably 0.1-50ppm.

Do not wish to be bound by theory, concentration known can not cause negative impact to the transmission of 193 nanometers up to the OH of about 1300ppm, but the inventor finds that surprisingly lower OH content has wholesome effect to LIWFD really.

In order to study and prove above-mentioned influence, the inventor has prepared the example of a series of synthetic silica glass optical materials by method well-known to those skilled in the art.Specifically, respectively to OH concentration be 10ppm, 150ppm and approximately three kinds of fused silica samples of 1000ppm apply energy density be 40 little Jiao/centimetre ²The laser of fixed 10,000,000,000 umber of pulses, and as shown in Figure 1 to the data mapping, form " best-fit " line that concerns between OH concentration that expression changes and the laser induced wavefront distortion.By Fig. 1 low OH concentration and the LIWFD dependency between reducing has been described." best-fit line " data declaration among Fig. 1, acceptable in order to obtain/minimum LIWFD, the OH concentration of synthetic silica glass optical material of the present invention should be approximately less than 600ppm.According to prerequisite, for obtain be subjected to about 193 nanometers of wavelength, energy density about 40 little Jiao/centimetre ²10,000,000,000 laser pulse irradiation after, have LIWFD for-1.0 to 1.0 nanometers/centimetre the synthetic silica glass optical material of laser tolerance, preferred OH concentration is more preferably less than 120ppm less than 200ppm.Most preferably OH concentration is 0.1-100ppm.

With the ppm by weight of OH is that the OH concentration of the fused silica of the present invention of unit is measured by the following method: be by measuring the infrared light transmission rate of this glass specifically, and use β-OH parameter to derive.Relevant wavelength region is 2-5 micron (5000 centimetres of wave-number ranges ^-1To 2000 centimetres ^-1).Can use conventional infrared spectrophotometer, FT-IR (Fourier transform infrared) spectrograph or color dispersion-type infrared spectrophotometer.For the measurement of high spatial resolution, for example variation of OH concentration can be used other equipment known in the art.

OH group in the fused silica has and is positioned at 2.72 microns (3676 centimetres ^-1), 2.21 microns (4525 centimetres ^-1) and 1.38 microns (7246 centimetres ^-1) near characteristic absorption band.

Parameter beta-OH is defined as the relative linear absorption coefficient of the hydroxyl (OH) in the glass matrix, the perhaps absorption of per unit path length.This parameter uses following formula to calculate:

$\mathrm{\&beta;}-\mathrm{OH}=\frac{1}{t}\log \frac{T_{\mathrm{ref}}}{T_{\mathrm{OH}}}$

In the formula:

T _Ref=in the reference position, (for example 4000 centimetres of non-absorbing wavelength ^-1) the sample transmittance;

T _OH=OH absorption peak place (for silicon-dioxide, is about 3676 centimetres ^-1) the sample transmittance;

T=thickness of sample (millimeter)

This β-OH value and the linear ratio of hydroxyl concentration.

The unit of OH concentration c is a mol, derives from the Beers-Lambert law

A＝ε·c·b

Light absorption ratio A=log (T in the formula _Ref/ T _OH), ε is a molar absorptivity, unit is for rising mole ^-1Centimetre ^-1, c is to be the concentration of unit with the mol, b is centimetre being the path length (thickness of sample) of unit.

(mole rises c ^-1)=A/ (ε b)

Therefore can use the density of glass and the molecular weight of OH (about 17 gram/moles), being calculated with the ppm by weight by the c that with the mol is unit is the OH concentration of unit.The constant ε of high-purity silicon dioxide glass under specific wavelength is that prior art is known.

One skilled in the art will appreciate that in the synthetic fused silica optical material and need certain amount of H ₂, so that laser induced degree of damage minimum, but inventor's discovery, in fact only need be less than 5.0 * 10 ¹⁷Molecule/centimetre ³Very little H ₂Content, so this content is preferred; Preferably H ₂Content is less than 2.0 * 10 ¹⁷Molecule/centimetre ³That is to say, carry out the measurement of hydrogen molecule concentration by the following method.Use has the JY Horiba T64000 spectrometer, measure Raman spectrum of EEV charge-coupled device (CCD) detector.By in the laser Raman spectroscopy at 4135 centimetres ^-1The hydrogen molecule scattering peak that records (I 4135) and at 800 centimetres ^-1The ratio of the intensity of the silicon-dioxide scattering peak that records (I 800) (being I 4135/I 800) acquisition hydrogen molecule concentration [molecule/centimetre ³] (V.S.Khotimchenko (^) etc., Zhurnal Prikladnoi Spektroskopii, 46 (6), 987-997 (1986)).More particularly,, the area below the peak is carried out integration, thereby determine the intensity at peak by linear fit or quadratic fit to background.It should be noted that in the method, detect and be limited to 1 * 10 ¹⁶Molecule/centimetre ³

Fig. 2 has shown among the figure under different energy densities below, five kinds of different synthetic silica glass optical materials (embodiment A-LIWFD (recording in 633 nanometers) E) and the funtcional relationship of laser (operating under about 193 nanometers) umber of pulse; Shown the graph of a relation of wavefront distortion (Y-axle) (its unit is for accounting for the mark of incident measuring light wavelength (633 nanometer)) among the figure with exposed pulse number (X-axle).Specifically, the wavefront distortion that records is that incident conplane (level) wavefront is refracted the spatial non-uniformity of rate and the interferential result of path length institute of variation.Five kinds of each free standard fused silica method preparations well known by persons skilled in the art of sample, the H of each sample ₂Molecular conecentration is less than present detectability, and five kinds of samples have the different OH concentration shown in the following Table I separately.Constant energy density shown in the following table I applies the pulse laser of 193 nanometers to each sample.The test of Fig. 2 shows these H ₂The sample that concentration is lower than present detectability shows the compression phenomena lower than needed degree; Specifically, when applying 10,000,000,000 laser pulses of about 193 nanometers of wavelength, energy density about 70 little Jiao/square centimeters, the LIWFD that records in 633 nanometers surpass 2 nanometers/centimetre.The inventor infers in view of the above, needs certain minimum H ₂Amount is so that the LIWFD minimum.

Table I

Embodiment	OH concentration (ppm by weight)	Energy density (little Jiao/centimetre 2/ pulse)
			Embodiment A	10	70
Embodiment B	1200	70
			Embodiment C	About 150	40
Embodiment D	About 300	70
			Embodiment E	About 1200	40

Use infrared array detector to surrounding fused silica sample of the present invention by the vast regional imaging of laser irradiation part; Described fused silica sample is the fused silica sample that has following embodiment 1 described composition and formed by described method specifically.Specifically, sample test comprise with 70 little Jiao/centimetre ²Energy density sample is applied 30,000,000,000 laser pulses.Infrared array image or OH array of figure show/have showed hydroxyl (being OH) graphic representation, and this graphic representation does not show because laser irradiation causes generating the trend of hydroxyl.More particularly, the OH curve data shows in the process of long-time laser explosure, has only formed the OH that is equal to or less than 0.3ppm in the exposure area.Do not wish to be bound by theory, if supposition hydrogen can as follows and SiO ₂Reaction generates SiOH and SiH:

Then this will illustrate only 1.1 * 10 ¹⁶Molecule/centimetre ³Hydrogen reaction has taken place.This explanation low hydrogen content can be accepted for low LIWFD.As mentioned above, 1 * 10 ¹⁵To 5.0 * 10 ¹⁷Molecule/centimetre ³Be acceptable, but preferred range is 8.0 * 10 ¹⁵To 2.0 * 10 ¹⁷Molecule/centimetre ³These low levelss also are preferred, show pure compression behavior to guarantee glass.Unpredictable LIWFD does not wish to occur, therefore by hanging down H ₂Content combines with low OH content (showing as low OH concentration), has guaranteed that the character of LIWFD will be pure compression.Although should be pointed out that not preferred swelling, a spot of " expansion " phenomenon is an acceptable.

Table II

The OH (ppm) that generates	The H that consumes 2(×10 17Molecule/centimetre 3)
		0.3	0.11
0.7	0.25
		1.0	0.39

As mentioned above, another advantage of preferred low hydrogen content is, adds in the process of step (will be described below) H of required maintenance in curing and one or more hydrogen ₂Add-on remains below and makes the hydrogen combustible concentration range that becomes.Preferably make H ₂Add-on is at these below concentration.Clearly, from the angle of manufacturing/production, preferably operate being lower than under the content of these flammable ranges.Table III has shown after the adding different hydrogen dividing potential drop, the hydrogen richness result in the glass.Use non-combustible gas to make the hydrogen richness in the glass reach requirement, this content is enough to realize low LIWFD.The target hydrogen richness that low LIWFD needs is 1 * 10 ¹⁵To 5.0 * 10 ¹⁷Molecule/centimetre ³, this hydrogen richness can use the hydrogen of non-combustible contents level to obtain in the low cost method in safety.

Table III

H in the atmosphere 2Percentage composition	Pressure (normal atmosphere)	H in the glass 2(10 17Molecule/centimetre 3)
			4	6	0.8-1.0
6	1	1.0-0.2

Annotate 1: non-combustible H ₂Content:＜6.2%H ₂/ surplus is N ₂(nitrogen) or helium

Annotate 2:H ₂Required atmosphere hydrogen in the load glass

4%H under the 70psi gauge pressure ₂/ N ₂The H that in glass, produces ₂Content is 0.8-1.0 * 10 ¹⁷Molecule/centimetre ³

6%H under the normal atmosphere ₂/ N ₂The H that in glass, produces ₂Content is 0.1-0.2 * 10 ¹⁷Molecule/centimetre ³

The existence that it should be noted that chlorine, basic metal, alkaline-earth metal and transition metal all can cause the transmittance of 193 nanometers to lose.Therefore, the cl content in the glass need be controlled at and be lower than 50ppm, the amount of basic metal, alkaline-earth metal and transition metal all is controlled at is lower than 10ppb, preferably be lower than 1ppb.

Up to now, mainly contain two kinds of methods and be used for making the synthetic fused silica material of the high purity that is used for optical applications.These methods are that soot becomes glass (soot-to-glass) method and directly becomes glass (direct-to-glass) method or " crystal block " method.

Become in the glass method at soot, silicon-dioxide soot particle generates in process furnace, and makes these particle depositions on surface of revolution by for example outside steam deposition (OVD) or vapor axial deposition methods such as (VAD), thereby forms the pre-type body of porous soot.Under sintering temperature, make transparent fixed high purity consolidation or the synthetic silica material of the fixed formation of the pre-type body of this soot then.These VAD/OVD methods have been widely used in the manufacturing of pre-moulded optical fiber, are that those skilled in the art are well-known therefore.Form silicon-dioxide soot particle by methods such as flame hydrolysiss under the temperature that directly becomes glass method to be usually included in to be higher than soot to become glass method, under the certain high temperature (for example about 1650 ℃) these soot particle depositions are being rotated on the surface of platen then, this temperature can make its fixed in position formation fused silica material, and described deposition is carried out being used for forming in the same process furnace of soot particulate usually.

The soot that is used for preparing the synthetic fused silica material of high purity becomes in the former prior art of glass method to be described to some extent.For example, U.S. Patent Application Publication has disclosed a kind of H No. 2003/0115905 ₂Content is 0.1 * 10 ¹⁶To 4.0 * 10 ¹⁶Molecule/centimetre ³, OH content is 125 to 450 ppm by weight, the SiH group content is less than 5 * 10 ¹⁶Molecule/centimetre ³, refractive index inhomogeneity is less than the fused silica blank of 2ppm.

According to the present invention, common above-mentioned synthetic silica glass optical material can prepare by following soot sedimentation:

A) provide the air-flow of the silicon-containing compound that comprises the steam form, described compound can generate silicon-dioxide by oxidation or flame hydrolysis generation thermolysis, make air communication cross the flame of burner, forms the amorphous granular of fused silica soot;

B) with described fused silica soot particle deposition on carrier, form the pre-type body of fused silica soot;

C) make the fixed formation transparent vitreous body of the pre-type body of described soot;

D) by containing H ₂The existence of gas under, vitreum is heated to is enough to make H ₂Diffuse into Vitrea temperature, thereby hydrogen is added in the vitreum.

In the step (a) of this method, the soot particle normally makes by the flame hydrolysis to the silicon precursor compound.Can be used to form pre-type body/Vitrea silicon precursor compound and preferably include the cyclosiloxane compound of any not halide, for example the polymethyl siloxane of hexamethyldisiloxane and so on, poly-methyl cyclosiloxane, and composition thereof.The special example of poly-methyl cyclosiloxane effectively comprise octamethylcyclotetrasiloxane, decamethylcyclopentaandoxane, hexamethyl cyclotrisiloxane, and composition thereof.

In special effective means of the present invention, use chemical formula--[SiO (CH ₃) ₂] ₄The cyclosiloxane compound (for example octamethylcyclotetrasiloxane OMCTS) of the not halide of-expression as the raw material of the pre-type body of fused silica, perhaps is used for vapour deposition process, for example is used for preparing the high purity fused silica that is used for the optical waveguide purposes.The silicon precursor compound of for example OMCTS (octamethylcyclotetrasiloxane) etc. and so on can be imported hydrogen, CH ₄Deng flame in, use O ₂Burning, thus the silicon-dioxide soot formed.Step (a) but using plasma is auxiliary.Although preferably when forming the pre-type body of soot, use the not compound of halide, can use SiCl ₄And so on chlorine-containing compound, but when being to use the compound of this class halide, need make chloride material in the final synthetic fused silica optical material minimum or eliminate wherein chloride material by some extra step.

In step (b), the silicon-dioxide soot can be deposited on supporting core bar or the mandrel, form porous insert, described core bar and mandrel can be for example conventional outside steam deposition (OVD) or used core bar and the mandrels of vapor axial deposition (VAD) method.If the use mandrel, the fixed mandrel that takes out before after deposition, in step (c), thus form hollow circle tube porous soot body.

Perhaps can be No. 6606883 pre-type body of described formation soot of United States Patent (USP) of " Method for Producing Fused Silica andDoped Fused Silica Glass " according to names such as Hrdina, according to the full text of this patent with reference to being combined in herein.According to this references, can pass through silicon-dioxide soot particle deposition on flat surfaces, to form smooth, the pre-type body of porous silicon-dioxide soot.Hereinafter will call " planar depositions " to this pre-type body sedimentation in the application.Preferably, described smooth deposition surface rotates and vibrates, to make the pre-type body of more uniform soot.

Described fixed (sintering) step (c) common rare gas element and H at helium and/or argon gas and so on ₂O and/or O ₂Existence under carry out.It should be noted that in order to make to have the higher OH concentration silica glass of (for example being higher than 50ppm), need be at H ₂Make the pre-type body of soot fixed under the existence of O.Will mention hereinafter, if fixed be at H ₂Carry out under the existence of O, then the final OH concentration in the silica glass is partly by the H in the fixed atmosphere ₂The O dividing potential drop is determined.Also can be but fixed at H ₂, O ₂, fluorochemicals etc. and so on the existence of other gases under carry out.In a specific implementations, fixed be included under about 900-1100 ℃ the temperature the pre-type body of described soot placed comprise He, Ar and/or contain N ₂And so on the process furnace of rare gas element in, the pre-type body of soot is heated to is enough to make its fixed temperature fully then; Be at least about 1500 ℃.

Can use the methods known in the art of chlorine processing etc. and so on that the pre-type body of soot is carried out purifying.As mentioned above, if pre-type body is to use the chloride silicon precursor of SiCl4 and so on to form,, may before fixed, remove the chlorine in the pre-type body if perhaps pre-type body uses the chlorine purifying.Dechlorination can use all gases to carry out, and these gases include but not limited to O ₂, H ₂O, fluorochemicals, contain Br compound etc., and their compatible mixture and combination thereof.

If in deposition step and consolidation step, do not use chlorine and compound thereof (for example in deposition step, to use not chloride precursor, in consolidation step, use not chloride purifying agent (Br for example ₂, HBr, Br ₂+ CO)), then the fused silica glass that is equipped with by these soot preforms will be not chloride.Yet,, before fixed, just must increase the dechlorination step, with the not chloride glass of preparation if these steps can not strictly keep not chloride.

After fixed formation vitreum, by comprising H ₂The existence of gas under, described vitreum is heated to is enough to make H ₂Diffuse into the temperature in the glass, and keep the sufficiently long time, thereby introduce hydrogen to vitreum.Recommended temperature is approximately higher than 350 ℃, and preferred temperature is 350-500 ℃, but temperature also can be up to 800 ℃.Make these samples under chosen temperature, keep for some time then, be enough to make hydrogen to diffuse into fully in the described whole vitreum during this period of time.Hydrogen partial pressure is 0.01 to 1 normal atmosphere, and surplus can be the rare gas element of nitrogen or argon gas and so on.

Have been found that the glass for specific OH content, the temperature that is used for adding hydrogen is influential to LIWFD.For low water content glass, particularly less than the glass of 200ppm, this adding temperature should be lower than 800 ℃ to OH content, preferably is lower than 600 ℃ approximately, to avoid significant compression (LIWFD).

Embodiment

Table IV has been reported the H of four kinds of synthetic silica glass optical materials ₂Concentration and OH concentration; Embodiment 1,2 and 3 is embodiments of the invention, and embodiment 4 is a comparative example.Prepared weight and surpassed 5 kilograms glass cylinder (will describe in detail hereinafter) approximately, downcut some webs from cylinder then, the pulse laser that makes these webs be exposed to about 193 nanometers of wavelength is measured its LIWFD (at the LIWFD of 633 nanometers mensuration); Notice that the test energy density of each sample lists in Table IV.

Table IV

Embodiment	H 2Concentration (* 10 7Molecule/centimetre 3)	OH concentration (ppm by weight)	Energy density (little Jiao/centimetre 2/ pulse)
				Embodiment 1	2.0	10	40
Embodiment 2	2.0	10	70
				Embodiment 3	1.8	150	40
Embodiment 4	1.7	1200	70

Embodiment 1 and 2: use octamethylcyclotetrasiloxane (OMCTS) as precursor, prepared the pre-type body of soot by the OVD method of describing in detail above.Then the pre-type body of this soot is placed 1050 ℃ interior processing of process furnace to make it fixed in 4 hours; Make the Cl of He and 2.7% simultaneously ₂Gaseous mixture flow in the atmosphere of process furnace.Use Cl ₂When still being in porous state, removes in glass wherein impurity and OH; Four hours time chien shih vitreum reaches its thermal equilibrium.Then, consolidation step is included in the O that makes He/3% ₂When gaseous mixture flows through this system, vitreum was kept 15 minutes again at 1050 ℃.The vitreum that will make like this with 3.1 ℃/minute speed is (at identical He/3%O then ₂Gaseous mixture in) be heated to 1235 ℃, be heated to 1345 ℃ with 0.47 ℃/minute speed then, be heated to 1490 ℃ with 0.42 ℃/minute speed then; Keep/provide comprising He and 3%O in some way ₂The gas of mixture, the vitreum that makes this gas sufficient to guarantee make like this has required OH concentration.Then vitreum is cooled to room temperature.

Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the Vitrea cylindrical sample that OH concentration is about 10ppm, then this cylindrical sample is heated to 350 ℃, and keeps 33 days in this temperature, to this cylinder at H ₂Handle under the atmosphere; Be H specifically ₂(volume) content greater than＞4.3%, surplus is the atmosphere of nitrogen, and this mixture is forced into 70psig.In case finish hydrogenation, make glass cylinder shape sample be cooled to room temperature.

Embodiment 3: use octamethylcyclotetrasiloxane (OMCTS) as precursor, prepared the pre-type body of soot by the OVD method of describing in detail above.Then the pre-type body of this soot is placed 1050 ℃ interior processing of process furnace to make it fixed in 4 hours; Make He and 2.7%Cl simultaneously ₂Gaseous mixture flow in the atmosphere of process furnace.Use Cl ₂When still being in porous state, removes in glass wherein impurity and OH; Four hours time chien shih vitreum reaches its thermal equilibrium.Then, fixed being included in makes He/3%O ₂Gaseous mixture when flowing through this system, vitreum was kept 15 minutes at 1050 ℃ again; He/O ₂Mixture can make any remaining organism of existence burn.The vitreum that will make like this with 3 ℃/minute speed is heated to 1235 ℃ then, is heated to 1345 ℃ with 0.47 ℃/minute speed then, is heated to 1430 ℃ with 0.25 ℃/minute speed then; (1235-1430 ℃) keeps/provides comprising He/H in some way in final heating steps ₂The gas of O mixture, the vitreum that makes this gas sufficient to guarantee make like this has required OH concentration.Then vitreum is cooled to room temperature.

Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the Vitrea cylindrical sample that OH concentration is 150ppm, then this cylindrical sample is heated to 350 ℃, and keeps 33 days in this temperature, to this glass cylinder at H ₂Handle under the atmosphere; Be H specifically ₂(volume) content is about 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 70psig.In case finish hydrogenation, make glass cylinder shape sample be cooled to room temperature.

Embodiment 4: the step that describes in detail according to above embodiment 3 has prepared the pre-type body of soot, and makes it fixed.

Then the vitreum that makes is like this carried out hydrogenation step, this step comprises and cuts out the cylindrical glass body sample that OH concentration is 1200ppm, according to above embodiment 3 described modes glass cylinder is carried out hydrogenation then.

Fig. 3 has below shown above-mentioned four kinds of laser induced wavefront distortion compressions that the synthetic silica glass optical material (embodiment 1-4) with different OH content is taken place among the figure; Specifically, shown the mutual relationship of wavefront distortion (Y-axis) (its unit is for accounting for the mark that wavelength of light (633 nanometer) is measured in incident) among the figure with umber of pulse (X-axis).Specifically, the wavefront distortion that records is that incident is in the interferential result that conplane wavefront is subjected to the path length of the spatial non-uniformity of specific refractory power and variation.Go up Table IV as mentioned above and also listed the laser energy density that in the LIWFD measuring process, each fused silica glass sample is applied.

More particularly, above-mentioned LIWFD measurement is carried out according to following steps.Downcutting web from above-mentioned cylindrical sample, it is polished, and make it be exposed to the radiation that ArF swashs wavelength 193 nanometers of base laser generation along its length, is the light beam that is exposed to 3 millimeters of diameters specifically.This laser apparatus is 4 kilo hertzs in repetition rate, works under the condition of 100% duty-cycle, and pulse length is about 30 nanoseconds (being generally 25-35 nanosecond).Approximately after per 3,000,000,000 to 4,000,000,000 subpulses, just sample is taken off from exposure apparatus, and characterize the laser infringement; Use the interferometric method of 633 nanometers in this test, this method of masurement can be to being undertaken quantitatively by laser induced optical path length variation of measuring under 633 nano wave lengths.After the measurement of test, sample is put back on the exposure system, in these until reaching target overall pulse number; The overall pulse number of every duplicate samples reaches 200-300 hundred million times usually.

Fig. 3 illustrates that non-embodiment 4 (OH of 1200ppm) with high OH content of the present invention has the LIWFD of extreme difference, and specifically, it has does not wish the high-expansion that exists.

Table V has been reported the H of nine kinds of synthetic silica glass optical materials that comprise above embodiment 1 ₂Molecular conecentration and OH concentration.Embodiment 1,5,6,8,9 and 12 is embodiments of the invention, and embodiment 7,10 and 11 is comparative examples.The same as before, prepared weight greater than 5 kilograms glass blank right cylinder (will be described in more detail below), measure its degree of birefringence and LIWFD (simultaneously at 193 nanometers and 633 nano measurement LIWFD) when being exposed to the pulse laser of 193 nanometers then.

Table V

Embodiment	H 2Concentration (* 10 17Molecule/centimetre 3)	OH concentration (ppm by weight)	Energy density (little Jiao/centimetre 2/ pulse)
				Embodiment 1	2.0	10	70
Embodiment 5	0.8	100-120	40
				Embodiment 6	1.6	About 94	40
Embodiment 7	1.2	1134	40
				Embodiment 8	0.76	About 120	40.2
Embodiment 9	0.72	About 94	10
				Embodiment 10	0.5	1280	40
Embodiment 11	0.5	100-120	40
				Embodiment 12	0.8	About 97	40

Embodiment 5: use octamethylcyclotetrasiloxane (OMCTS) as precursor, be equipped with the pre-type body of soot by the OVD legal system identical with the method that describes in detail above.Then the pre-type body of soot is placed and handle 4 hours in 950 ℃ the process furnace to be cured; The gas that comprises He is flowed in the atmosphere of this process furnace.Be immersed in and contain in the He atmosphere after 4 hours, atmosphere is converted into He/3%O ₂Mixture; Use O ₂Remove any remaining organism that may exist.Make vitreum at He/O then ₂Submergence 3 hours again in the mixture (950 ℃) makes temperature rise to 1235 ℃ with 3.1 ℃/minute speed then, rises to 1345 ℃ with 0.47 ℃/minute speed then, rises to 1490 ℃ with 0.42 ℃/minute speed then; Provide/keep this He/3%O in some way ₂Mixture, the vitreum that makes this gas sufficient to guarantee make like this has required OH concentration.Then vitreum is cooled to room temperature.

Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the vitreum cylindrical sample that OH concentration is about 100-120ppm, then this cylindrical sample is heated to 350 ℃, and keeps 33 days in this temperature, and this cylindrical sample is applied H ₂Atmosphere; Be H specifically ₂(volume) content is about 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 43psig.In case finish hydrogenation, make glass cylinder shape sample be cooled to room temperature.

Embodiment 6: the step of describing in detail according to embodiment 5 has prepared the pre-type body of soot, and makes it fixed.Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the glass cylinder shape sample that average OH concentration is about 94ppm, then this glass cylinder is heated to 350 ℃, and is containing H ₂In the atmosphere, kept 33 days in this temperature; Described atmosphere is H specifically ₂(volume) content is about 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 55psig.In case finish hydrogenation step, make glass cylinder shape sample be cooled to room temperature.

Embodiment 7: the step according to above embodiment 3 describes in detail has prepared the pre-type body of soot, and has made it fixed.

Vitreum to such formation carries out hydrogenation step then, this step comprises and cuts out the vitreum cylindrical sample that OH concentration is 1134ppm, according to above embodiment 3 described modes this glass cylinder is carried out hydrogenation step then, this cylindrical sample is heated to 350 ℃, and, this cylindrical sample is applied H this temperature maintenance 33 days ₂Atmosphere; Be H specifically ₂(volume) content is about 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 100psig.In case finish hydrogenation step, make glass cylinder shape sample be cooled to room temperature.

Embodiment 8: the step of describing in detail according to above embodiment 5 has prepared the pre-type body of soot, and makes it fixed.According to the Vitrea step that is used for embodiment 5 vitreum of such preparation is carried out hydrogenation then.

Embodiment 9: the step of describing in detail according to embodiment 5 has prepared the pre-type body of soot and has made it fixed.Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the glass cylinder shape sample that average OH concentration is about 94ppm, then this glass cylinder is heated to 500 ℃, and is containing H ₂In the atmosphere, kept 7 days in this temperature; Described atmosphere is H specifically ₂(volume) content is 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 55psig.

Embodiment 10: the step of describing in detail according to above embodiment 3 has prepared the pre-type body of soot and has made it fixed.

Annealing and hydrogenation step that the vitreum of such formation is made up, this step comprises and cuts out the glass cylinder shape sample that average OH concentration is about 1280ppm, with 10 ℃/minute speed this right cylinder is heated to 1200 ℃ then, and kept 10 hours in this temperature.With 5 ℃/hour speed this glass cylinder is cooled to 1100 ℃ then, kept then 116 hours, be cooled to 900 ℃ with 5 ℃/hour speed then, be cooled to room temperature with 30 ℃/hour speed then.Whole annealing/hydrogenation step is containing H ₂Atmosphere in finish; Specifically, described atmosphere is H ₂(volume) content is 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 70psig.

Embodiment 11: the step of describing in detail according to embodiment 5 has prepared the pre-type body of soot, and makes it fixed.According to above embodiment 10 described methods, the vitreum of such formation is annealed and hydrogenation then with combination step.

Embodiment 12: the step of describing in detail according to above embodiment 5 has prepared the pre-type body of soot and has made it fixed.Vitreum to such formation carries out hydrogenation step then, and this step comprises and cuts out the glass cylinder shape sample that average OH concentration is about 97ppm, then this glass cylinder is heated to 500 ℃, and is containing H ₂In the atmosphere, kept 7 days in this temperature; Described atmosphere is H specifically ₂(volume) content is 4%, surplus is the atmosphere of nitrogen, and this mixture is forced into 55psig.

Fig. 4 below, shown among the figure a series of of the present invention/LIWFD that occurs in the synthetic silica glass optical material relatively; Specifically, shown relation between the umber of pulse (X-axis) of laser of wavefront distortion (Y-axis) (is unit to account for the mark that incident detects the wavelength (633 nanometer) of light) and 193 nanometers among the figure.Last Table V has been listed the constant energy density of the laser that in the LIWFD test process each web (downcutting from glass cylinder shape sample) is applied.Testing method is identical with the described method of last Fig. 3.Therefore, in Fig. 4, recorded because embodiment is exposed to the LIWFD that the radiation of wavelength 193 nanometers produces in 633 nanometers.

Fig. 5 has below shown the funtcional relationship of umber of pulse of the laser pulse of the degree of birefringence of synthetic silica optical material of the present invention/comparison of describing in detail above and wavelength 193 nanometers among the figure.Testing method is described identical with last Fig. 3, and its difference is that degree of birefringence is to use the degree of birefringence measuring system, with the optical measurement of wavelength 633 nanometers.

Fig. 6 below, shown among the figure a series of of the present invention/funtcional relationship of the umber of pulse of the LIWFD of synthetic silica glass optical material relatively and the laser of about 193 nanometers of wavelength; Specifically, shown the relation of wavefront distortion (Y-axis) (unit is for accounting for the mark of incident measuring light wavelength (193 nanometer)) among the figure with the umber of pulse (X-axis) of 193 nanometers.In the embodiment of Fig. 6 used energy density be with Fig. 4 in the identical energy density of exposure light of 193 nanometers.Yet the LIWFD of Chan Shenging is at 193 nano measurements like this, rather than at 633 nano measurements.

The test of Fig. 4-6 explanation comparative example 7,10 and 11 has does not separately wish the LIWFD phenomenon that exists.Specifically, should note the sample of two kinds of high OH content, embodiment 7 and 10 (be respectively 1134 and 1280ppm) has makes us the LIWFD phenomenon (overplumping) that can't receive.On the other hand, embodiment 11 has the phenomenon (under 10,000,000,000 pulses greater than 1 nanometer/centimetre) of excess shrinkage, this phenomenon partly be since when carrying out hydrogenation step too high temperature (1200 ℃) cause; This temperature is higher than the hydrogenation temperature of above-mentioned 800 ℃ (preferred 600 ℃) far away.

Compare with the synthetic silica optical material of prior art, the advantage of synthetic silica optical material of the present invention comprises: (1) is stable and slight by laser induced infringement phenomenon, this point is that the fused silica lens are required, and this can improve the character/performance of lens.

It will be apparent for a person skilled in the art that and under the prerequisite that does not deviate from the principle of the invention or scope, to carry out various changes to the present invention. Therefore, if these changes of the present invention and be modified in the appended claims and the scope that is equal within, these changes and revise and will comprise in the present invention.

Claims (30)

1. One kind be used for wavelength less than the zone of 250 nanometers, and can tolerate the synthetic silica glass optical material of the optics infringement in this zone, the H of described synthetic silica glass optical material ₂Concentration is less than about 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 600ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
2. 2. synthetic silica glass optical material as claimed in claim 1 is characterized in that, described H ₂Concentration is about 0.4 to 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 200ppm.
3. 3. synthetic silica glass optical material as claimed in claim 1 is characterized in that, described H ₂Concentration is less than about 2.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 200ppm.
4. 4. synthetic silica glass optical material as claimed in claim 3 is characterized in that, described OH concentration is about 30-200ppm.
5. 5. synthetic silica glass optical material as claimed in claim 1 is characterized in that, described H ₂Concentration is about 0.1 to 2.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 125ppm.
6. 6. synthetic silica glass optical material as claimed in claim 5 is characterized in that, described OH concentration is about 50-100ppm.
7. 7. synthetic silica glass optical material as claimed in claim 3 is characterized in that, described OH concentration is about 0.1-100ppm, H ₂Concentration is about 0.1 to 1.0 * 10 ¹⁷Molecule/centimetre ³
8. 8. synthetic silica glass optical material as claimed in claim 7 is characterized in that, described OH concentration is about 0.1-50ppm.
9. 9. synthetic silica glass optical material as claimed in claim 8 is characterized in that, described H ₂Concentration is about 0.4 to 1.0 * 10 ¹⁷Molecule/centimetre ³
10. 10. synthetic silica glass optical material as claimed in claim 1 is characterized in that, when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 1.0 nanometer/centimetre.
11. 11. synthetic silica glass optical material as claimed in claim 1 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.5 to 0.5 nanometer/centimetre.
12. 12. synthetic silica glass optical material as claimed in claim 11 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 0.5 nanometer/centimetre.
13. 13. one kind be used for wavelength less than the zone of 250 nanometers, and can tolerate the synthetic silica glass optical material of the optics infringement in this zone, the H of described synthetic silica glass optical material ₂Concentration is about 0.1 to 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 125ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
14. 14. synthetic silica glass optical material as claimed in claim 13 is characterized in that, described H ₂Concentration is about 0.4 to 5.0 * 10 ¹⁷Molecule/centimetre ³
15. 15. synthetic silica glass optical material as claimed in claim 14 is characterized in that, described H ₂Concentration is about 0.4 to 2.0 * 10 ¹⁷Molecule/centimetre ³
16. 16. synthetic silica glass optical material as claimed in claim 13 is characterized in that, described OH concentration is about 0.1-100ppm.
17. 17. synthetic silica glass optical material as claimed in claim 13 is characterized in that, when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 1.0 nanometer/centimetre.
18. 18. synthetic silica glass optical material as claimed in claim 13 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.5 to 0.5 nanometer/centimetre.
19. 19. synthetic silica glass optical material as claimed in claim 18 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 0.5 nanometer/centimetre.
20. 20. one kind be used for wavelength less than the zone of 250 nanometers, and can tolerate the synthetic silica glass optical material of the optics infringement in this zone, the H of described synthetic silica glass optical material ₂Concentration is about 0.4 to 1.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 600ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
21. 21. synthetic silica glass optical material as claimed in claim 20 is characterized in that, described OH concentration is less than about 200ppm.
22. 22. synthetic silica glass optical material as claimed in claim 21 is characterized in that, when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 1.0 nanometer/centimetre.
23. 23. synthetic silica glass optical material as claimed in claim 20 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.5 to 0.5 nanometer/centimetre.
24. 24. synthetic silica glass optical material as claimed in claim 23 is characterized in that, when its be subjected to about 193 nanometers and about 40 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-0.1 to 0.5 nanometer/centimetre.
25. 25. synthetic silica glass optical material as claimed in claim 20 is characterized in that, described OH concentration is about 0.1-200ppm.
26. 26. one kind be used for wavelength less than the zone of 250 nanometers, and can tolerate the synthetic silica glass optical material of the optics infringement in this zone, the H of described synthetic silica glass optical material ₂Concentration is about 0.4 to 1.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is that 100ppm is to about 600ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
27. 27. one kind be used for wavelength less than the zone of 250 nanometers, and can tolerate the synthetic silica glass optical material of the optics infringement in this zone, the H of described synthetic silica glass optical material ₂Concentration is 0.1 to 0.5 * 10 ¹⁷Molecule/centimetre ³, OH concentration is 100-125ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
28. 28. a method that is used for preparing synthetic silica glass optical material, this method may further comprise the steps:

    A) provide the air-flow that comprises the silicon-containing compound that is the steam form, described compound can be converted into silicon-dioxide by oxidation or flame hydrolysis generation thermolysis; And make this air-flow feed the flame of burner, form the amorphous granular of fused silica soot;

    B) with described fused silica soot particle deposition on carrier, form the pre-type body of fused silica soot;

    C) make the fixed formation transparent vitreous body of the pre-type body of described soot;

    D) by containing H ₂The existence of gas under described vitreum be heated to be enough to make H ₂Diffuse into Vitrea temperature, hydrogen is added in the described vitreum;

    Make the silica glass optical material thus, the H of this material ₂Concentration is less than about 5.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 600ppm; And when its be subjected to about 193 nanometers and about 70 little Jiao/centimetre ²Energy density under 10,000,000,000 laser pulses operating do the time spent, 633 nanometers record its laser induced wavefront distortion for-1.0 to 1.0 nanometers/centimetre.
29. 29. method as claimed in claim 28 is characterized in that, described Vitrea H ₂Concentration is less than about 2.0 * 10 ¹⁷Molecule/centimetre ³, OH concentration is less than about 200ppm, and described hydrogenation step carries out being less than about under 800 ℃ the temperature.
30. 30. method as claimed in claim 29 is characterized in that, described hydrogenation step carries out being lower than under about 600 ℃ temperature.

Images