Production manufacturing quartz glass and articles thereof
The present invention relates to transparent quartz glass of high purity produced by molding powdery amorphous silica, and sintering and fusing the molded article of amorphous silica. Particularly, the present invention relates to pure transparent quartz glass which contains less impurities like alkalis respectively at a content of not more than 1 ppm, contains less water, and has high heat resistance, thereby being useful for a photomask and other uses in semiconductor production. Conventionally, transparent quartz glass is produced by a process of melting powdery quartz crystal in vacuo in a furnace, a process of melting powdery quartz crystal by oxyhydrogen flame, or a like process. However, the conventional processes employ powdered natural quartz crystal, whereby the resulting quartz glass is not satisfactory to meet the severe requirements for high purity for highly integrated LSI, even though the quartz glass has high heat resistance. Although the powdered natural quartz crystal is treated for high purity, not all of the undesired impurities can be removed to respective contents of not higher than 1 ppm at the moment.VIDEO ON THE TOPIC: Glass manufacturing process - update 2019
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- CROSS-REFERENCE TO RELATED APPLICATIONS
- US5665133A - Process for production of pure transparent quartz - Google Patents
- US6920766B2 - Apparatus for producing synthetic quartz glass - Google Patents
- DE102006060561B4 - Process for producing a quartz glass molded body - Google Patents
- Method of producing quartz ceramics and articles thereof
- US20020046992A1 - Plasma resistant quartz glass jig - Google Patents
- EP2511402A4 - Silica vessel and process for production thereof - Google Patents
- Customs Tariff Number Chapter 70 - Search results (172)
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional application of application Ser. The invention relates to a synthetic quartz glass preform and a device for producing the same. In accordance with developments in the semiconductor industry, and utilization of the products from the semiconductor industry in various fields of application, as well as due to independent developments, in particular in the special fields of materials management and medicine, light sources with very high energy densities find application.
Particularly, these are excimer laser with operation wavelengths of nm and nm. The optical components used thereby for imaging and directing the radiation, as well as the photomasks which exclusively consist of synthetic quartz glass or calcium fluoride have to satisfy the required optical quality and must not lose the same in continuous operation.
The most important high-quality features of the optical components and the most difficult ones to be set, are optical homogeneity and stability with respect to excimer laser irradiation in the deep ultra-violet light DUV. Therefore, there was no lack of trials in the past to obtain such high-quality features permanently and reproducibly.
Hence, there is known a method for producing a homogeneous, striae free body of quartz glass from DE 42 04 A1, in which a rod-shaped initial body is twisted, multiply thermally remodeled in a mould of suitable foreign material and twisted again.
In the EP 0 A1 this method is modified under avoidance of any contact with a foreign material in such a manner that a quartz glass body subsequently produced according to the method is optically homogeneous in three directions and additionally is stable with respect to excimer laser radiation.
However, EP 0 A1 does not teach to which degree this stability is achieved. Additionally, the method is considerably time and cost consuming. Synthetic quartz glass is characterized by having very good transmission in the deep range of ultra-violet light DUV. When it is exposed to high energy short-wave radiation as, for example, provided by excimer lasers at nm and nm, photochemical reactions will result, which will lead to the formation of paramagnetic defects, the latter being responsible for the formation of absorption bands and the development of luminescence.
The power of these photochemical reactions depends on intrinsic defects in the form of binding anomalies. The photochemical reactions are also intensified by contaminants in a network as given, for example, by atoms of transition metals and chlorine.
Parallel to these photochemical reactions which impair the optical properties of the quartz glass, annealing processes take place for which an OH content and a content of free hydrogen in the quartz glass is of importance.
From the subsequently discussed prior art it is known to desensitize synthetic quartz glass to high-energy radiation in the DUV by the following measures carried out individually or in combination: introducing molecular hydrogen into the quartz glass bulk, using particularly pure starting raw material, using chlorine free starting raw material, and doping the quartz glass with fluorine and others.
The EP 0 A1 U. It is disadvantageous that an aftertreatment of the silica glass is necessary including extensive safety measures required thereto.
Furthermore, the produced silica glass bodies exhibiting the desired properties may not be of very large volume. The EP 0 A1 reference describes a method for producing quartz glass which is adapted to be exposed to an excimer laser irradiation. The method does not function without a specific homogenizing step which renders it expensive. The stability is specified with 1. The stability of this quartz glass against excimer laser irradiation at a low absorption is only disclosed up to a low 10 shot rate of 0.
The comparatively low stability is explained in that a dehydration step provided for in the manufacturing process leads to an increase of the Cl content which, in turn, reduces the DUV stability.
An additionally provided homogenizing step renders the method more expensive. This solution is little or not at all suited for the production of imaging optical members in the DUV range, which are subject to considerably higher requirements with regard to the transmission and the optical homogeneity than photomasks. Such a preform shows profiles of the OH concentration, of the Cl concentration and of a fictitious temperature which are to be adjusted for obtaining a high refractive index of homogeneity.
The method for producing the optical components comprises, in each case, steps for removing stratifications and for doping with hydrogen which renders the entire production process complicated and expensive.
The OH concentration distribution is axially symmetrical. Also in this case, stratifications have to be removed and doping with hydrogen has to be carried out in the course of manufacturing the optical components. Considerable and expensive efforts have to be made to obtain a high purity of the quartz glass, which also finds expression in that special measures have to be taken for storing the basic materials.
In the EP 0 A1 reference, a method for the heat treatment and consolidation of a quartz glass preform is described whereby a reduction of the laser induced defects in the quartz glass is asserted to be obtained. There is nothing reported of the refractive index homogeneity, of the form and mass of the bodies to be produced, of a feasible application of the produced quartz glass under extreme conditions. The represented increases in absorption at nm and nm, respectively, are only acceptable up to few million shots.
EP 0 A1 discloses an improved method for producing a body of synthetic silica glass. A burner comprising at least five nozzles is supplied with fuel gas in such a manner that the produced synthetic silica glass shows an OH content optimized compared to the H 2 content. There is nothing reported with respect to the DUV stability and the refractive index homogeneity. For obtaining OH contents above ppm, this procedure is unstable with respect to the attainable growth behavior.
In EP A1, a quartz glass, an optical component containing this quartz glass and a manufacturing process for the quartz glass are described. For the production of the preforms a downward directed burner is employed. The stability of the quartz glass with respect to the excimer laser irradiation lies at a comparatively low shot rate of about 10 6. The OH concentration of the quartz glass substantially lies at only ppm.
In EP 0 A1 there is described a quartz glass for photolithographic applications, an optical component containing said quartz glass, a photolithographic device containing said component, and a method for producing the quartz glass. There are conditions disclosed for producing a preform which can also be utilized in the DUV. However, the stability of the quartz glass against excimer laser irradiation is only represented up to 10 6 shots.
The quartz glass is subjected to an F-doping which ensures, as known, low dispersion losses and has a favorable effect on the DUV stability. However, a high optical homogeneity of the melted quartz glass will not be attainable owing to the F-doping. In the course of SiO 2 deposit on places with the highest temperature, there also develop the highest OH concentration and the highest F concentration. Hence, an error is introduced which increases the gradient of the refractive index curve.
Finally, EP 0 describes a method for producing quartz glass in which the growth process of the quartz glass produced synthetically takes place in an upright direction. The process is controlled in such a manner that the stratification is adapted to take place only vertically to the growth direction of the preform. By virtue of the present invention the disadvantages of the prior synthetic quartz glasses are obviated which, up to now, did not permit the utilization of the same in extreme applications in the DUV.
Therefore, it is an object of the present invention to produce, under use of a flame hydrolysis technique, a synthetic quartz glass which meets highest requirements concerning stability with respect to excimer laser irradiation in the DUV at a high energy density and concerning optical homogeneity.
It is a further object of present invention to provide a device which is particularly suited in the manufacture of the quartz glass and which renders the output of the manufacturing process maximal. According to the present invention, the objects are realized by the characteristic features described herein.
It is also feasible to employ radiation of other wavelengths, provided that the same lies under nm. The transmission reduction corresponds to damage behavior for values stated herein.
Hence, it lies within the scope of the invention. It can be generally stated that a varied reduction of the internal transmission takes place at a radiation variation, but an unchanged damage behavior.
Damage behavior is to be understood by someone skilled in the art as a long-term damage, for example, a transmission variation of synthetic quartz glass under the effect of an excimer laser irradiation. It shows neither an axial stratification nor a stratification at right angles to its direction of growth; its entire volume is free from stratifications.
The growth range of the drum-shaped preform has an at least almost flat part close to the center, which substantially conforms to the core, and a peripheral part with a parabolic face which passes over into a cylindrical surface of the drum-shaped preform. The cross-sectional area of the preform which can be utilized for different purposes and in which the quality of the synthetic quartz meets the respective requirements is different. Thus, for example, it is sufficient when used in illumination systems for excimer laser, that the synthetic quartz glass has high stability and transmission at an adequate homogeneity.
The Cl content of the same does not exceed 20 ppm and preferably is 5 to 15 ppm. A preform having the abovementioned parameters is, to a high degree, stable against high energy DUV irradiation, shows a high refractive index stability and is excellent for the production of optical members such as DUV stepper-lenses, directing members for laser beams, photomasks etc. Thereby, traces of contaminating elements e.
The preform does not require any additional doping with H 2 , F and others, to render it serviceable for tasks in DUV excimer laser irradiation. Also a subsequent treatment of the synthetic quartz glass in a reducing atmosphere is not required. If necessary, it is advantageous to cut optical members out of the material of the core area.
A device for producing the preform comprises a substantially horizontal muffle with two differently sized arranged openings opposing each other, the larger of which is adapted for inserting the preform and the smaller one for inserting a burner, and an internal chamber which narrows from the larger opening to the smaller opening. The burner is provided with nozzles which are coaxially arranged to each other and to the burner axis, the centrally arranged nozzle discharges the basic material, for example, SiCl 4 and O 2 and the external nozzles the fuel gas, for example, H 2 and O 2 , parallel to one another and to the burner axis.
The narrowing substantially is a gradual one. Unlike similar prior devices, the muffle has neither an opening nor a bulge on its top-side. The overall length of the muffle is at least twice the size of the diameter of the vitreous preform. The almost planar leading face of the latter is preferably arranged in the center of the internal chamber of the muffle.
The muffle is preferably embodied in three layers in order to ensure a sufficient and constant internal temperature as well as a low heat emission. It is advantageous, when the distance of the substantially rotation-symmetrical preform surface relative to the internal limiting face is 5 to mm depending on the flow conditions for the waste gas.
Furthermore, it is advantageous, when the distance of the burner to the preform is to mm in dependence on the geometry of the burner nozzles and the flow of the fuel gases volume. As to the smaller opening, in which the burner is arranged for free movement, a diameter of 50 to mm is to be recommended.
Due to the internal geometry of the muffle and the operation of the burner, the device of the present invention ensures that the preform is definedly distributed by the fuel gas as well as that preforms of principally optional lengths can be the melted on.
No subsequent treatment twisting, doping is required for the preform. A modification of geometry in order to adapt the preform to the intended application can be combined with a heating of the preform. In spite of extreme process control the device permits melting preform masses of 50 kg and more, in a normal melting process, which are optically homogeneous and stable in the DUV against high-energy laser beams.
The invention will be explained hereinafter in more detail by virtue of the schematic drawings. There is shown in:. In FIG. The muffle 10 has an internal chamber 14 with a smaller opening 15 for inserting a burner 16 and a larger opening 17 via which a preform 18 to be melted on protrudes into the muffle 10 , the geometrical axis of said preform coincides with an axis of rotation X—X. At least a portion of the muffle 10 which envelopes the preform 18 is at least approximately symmetrical about the axis X—X, too.
There is a space a between a parabolic face 19 of the preform 18 and a limiting surface 20 of the internal chamber The space a advantageously is not larger than 50 mm and not smaller than 15 mm in order to eliminate deposits on the limiting surface 20 by the material to be melted. In the internal chamber 14 , the preform 18 is provided with a cap 21 having a substantially planar leading face of which a plateau 22 lies in the center of the muffle 10 and is at right angles to the axis X—X.
The parabolic lateral face 19 of the preform 18 is a side of the cap Via the opening 15 , which in the present embodiment has a diameter of 60 mm, the burner 16 is inserted into that portion of the muffle 10 which deviates from the axial symmetry, in such a manner that its axis Y—Y is slightly inclined relative to the axis of rotation X—X and intersects the plateau 22 below the intersection point of the axis of rotation X—X and the plateau The burner 16 is provided with a plurality of nozzles, not shown in detail, which are in parallel to each other.
The burner 16 is adjustable within the opening The torch 23 of the burner 16 is directed towards the plateau The preform 18 has an axially symmetrical refractive index profile.
US5665133A - Process for production of pure transparent quartz - Google Patents
The invention concerns a quartz glass body for an optical component for transmitting UV radiation with a wavelength of nm and less, in particular a wavelength of nm, as well as a process for the manufacture of the quartz glass body whereby fine quartz glass particles are formed by means of flame hydrolysis of a silicon compound, deposited and vitrified. Optical components of synthetic quartz glass are used in particular for the transmission of high energy UV laser radiation, for example in exposure optics of microlithographic apparatus for the manufacture of highly integrated circuits in semiconductor chips. Modern microlithographic devices use excimer lasers which generate high energy pulsed UV radiation with a wavelength of nm KrF lasers , nm ArF lasers , or nm F 2 lasers. However, with such short wave radiation, structural defects and corresponding absorptions come into play, which are characteristic of the type and quality of the respective quartz glass bodies.
US6920766B2 - Apparatus for producing synthetic quartz glass - Google Patents
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DE102006060561B4 - Process for producing a quartz glass molded body - Google Patents
In a known method for producing quartz glass that is doped with nitrogen, an SiO 2 base product is prepared in the form of SiO 2 grains or in the form of a porous semi-finished product produced from the SiO 2 grains and the SiO 2 base product is processed into the quartz glass with the nitrogen chemically bound therein in a hot process in an atmosphere containing a reaction gas containing nitrogen. From this starting point, a method is provided for achieving nitrogen doping in quartz glass with as high a fraction of chemically bound nitrogen as possible. The present invention refers to a method for producing nitrogen-doped quartz glass in which a SiO 2 base product is provided in the form of SiO 2 grains or in the form of a porous semifinished product produced from the SiO 2 grains and the SiO 2 base product is processed into the quartz glass with the nitrogen chemically bound therein in a hot process in an atmosphere containing a reaction gas containing nitrogen. Furthermore, the present invention refers to quartz glass grains suited for carrying out the method.
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Method of producing quartz ceramics and articles thereof
Effective date : Year of fee payment : 4. Year of fee payment : 8. Year of fee payment :SEE VIDEO BY TOPIC: How to make pure, synthetic quartz
This application claims the benefits of U. The present invention relates to a glass composition and products made thereof, having very little variation in key properties within any given lot of the glass composition. In glass applications such as liquid crystal panels, optical communication devices for instance optical filters and optical switches, recording medium, halogen and High Intensity Discharge HID lamps etc. High-energy laser systems employ multiple large pieces of optical quality glass, sometimes thousands of large size laser glass pieces, and it is imperative for the pieces to have consistent optical quality. Glass compositions, similarly to fused quartz compositions, are characterized by a few fundamental properties affecting the manufacturing of or the properties of products employing the compositions, i. The effect of OH hydroxyl on viscosity of glass or quartz is widely known.
US20020046992A1 - Plasma resistant quartz glass jig - Google Patents
This is a divisional application of application Ser. The invention relates to a synthetic quartz glass preform and a device for producing the same. In accordance with developments in the semiconductor industry, and utilization of the products from the semiconductor industry in various fields of application, as well as due to independent developments, in particular in the special fields of materials management and medicine, light sources with very high energy densities find application. Particularly, these are excimer laser with operation wavelengths of nm and nm. The optical components used thereby for imaging and directing the radiation, as well as the photomasks which exclusively consist of synthetic quartz glass or calcium fluoride have to satisfy the required optical quality and must not lose the same in continuous operation.
Effective date : The invention relates to a method for the production of quartz glass molded bodies which, in particular as containers or crucibles for the liquefaction of non-metals or non-ferrous metals and in particular for the production of silicon blocks, from which photovoltaic modules are produced, have an improved surface purity. For the production of silicon blocks mainly sintered quartz glass containers are used. Such containers or moldings and their production methods are for example from DE 51 A1 or the DE 44 C1 known. The containers are manufactured essentially with the following method steps.
EP2511402A4 - Silica vessel and process for production thereof - Google Patents
An improved sol-gel process is disclosed for fabri-cating large monoliths of silica or ceramic material, which are substantially free of cracks. This hydrothermal aging treatment causes sili-ca or ceramic particles to migrate and fill small pores in the porous gel matrix, such that the average pore size increases and capillary forces encountered in the subse-quent drying step 70 are reduced to a point where cracking of the gel is substantially eliminated. USA en. EPB1 en.
Customs Tariff Number Chapter 70 - Search results (172)
The invention pertains to a process for the production of silica granulate by mixing silicic acid powder with a liquid. Silica powders can be produced by means of gas-phase reactions such as by the hydrolysis of silicon halides or organic silicon compounds. They can also be produced by means of sol-gel processes.
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The HS-Codenumbers or contents may have changed. Search in the current year. Cullet and other waste and scrap of glass; glass in the mass excl. Cullet and other waste and scrap of glass excl. Glass in balls, rods or tubes, unworked excl. Glass in balls, unworked excl. Tubes of glass having a linear coefficient of expansion 70
Year of fee payment : 4. Year of fee payment : 8. An object of the invention is to provide a quartz glass crucible reduced in the generation of vibration occurring on the surface of a silicon melt and free from the generation of rough surface and cristobalite spots, yet capable of pulling up single crystal silicon stably and at high yield even in long-term operations; it is also an object to provide a method for producing the same.