Apparatus and method for producing hollow quartz cylinders

Abstract

The present disclosure relates to manufacturing quartz hollow cylinders with reduced bubbles using atmospheric control. An example horizontal rotating arc furnace (100) includes a housing (104), a support (106), and a rotary joint (120). The housing defines an interior configured to receive silica particles and an electrode to generate a plasma arc, and the housing includes a plurality of first ports (102) fluidly connected to the interior on an exterior of the housing and a supply conduit (124) fluidly coupled to the first ports. The support (106) mechanically couples the housing (104) to a drive system (118) to provide rotational motion to the housing (104). The rotary joint (120) is coupled to the housing (104) and includes a second port (122) fluidly connected to a vacuum supply. The second port (122) is fluidly connected to the first ports (102) via the supply conduit (124). The horizontal rotating arc furnace (100) is configured to apply a vacuum to the interior of the housing (104) via the first ports (102) as the housing rotates.

Description

[0001] Cross-application of related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 114,009, filed November 16, 2020, entitled “Systems and Method for Producing Hollow Quartz Cylinders,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates generally to the manufacture of hollow quartz cylinders, and more specifically, to the manufacture of hollow quartz cylinders with reduced air bubbles using atmospheric control. Background Technology

[0004] Hollow cylinders of silica (SiO2) glass (sometimes referred to as "fused silica" or "quartz glass") are used in semiconductor wafer fabrication. During certain processing steps, such as masking, deposition, and etching, semiconductor material is placed inside the cylinder. For example, due to the corrosive nature of etching processes, the etching chamber material is chosen to withstand harsh environments to facilitate reliable wafer fabrication. Therefore, the innermost etching chamber components are typically made of quartz glass. Etching of pure quartz glass theoretically results only in the release of silicon and oxygen. Compared to transition metals and other elements, these are less harmful to the wafer, as they can alter the wafer's composition and thus its semiconductor properties.

[0005] There are many methods for producing hollow quartz cylinders. Some examples include spray melting followed by drilling to form a core, direct stretching through a mold and core, and hot reflow of existing cylinders. Another method for forming cylinders is via a rotary furnace. In this method, sand is typically sprayed into the rotary furnace chamber. The sand is held on the inner surface of the chamber by centrifugal force. Electrodes are then introduced into the chamber. A plasma arc between the electrodes provides heat to melt the quartz. The sand melts radially from the inner layer (i.e., the sand closest to the heat source). The hollow cylinder is then allowed to cool. While these methods are generally suitable for forming quartz cylinders, the cylinders may still exhibit a certain concentration of impurities such as bubbles and inclusions, which may be insufficient for their intended applications. Summary of the Invention

[0006] This disclosure relates to the manufacture of hollow quartz cylinders with reduced bubble formation using atmospheric control. To control the atmosphere within a rotating electric arc furnace, the cylinder body of the furnace includes ports with porous plugs on the exterior of the cylinder body. These ports are fluidly connected to manifolds, allowing a vacuum to be drawn into the space between the sand grains after melting of the inner surface. In some examples, two or more sets of ports are fluidly connected to two or more manifolds, such that a vacuum can be applied to some ports and highly diffusive gases (e.g., helium, hydrogen, mixtures thereof) can be introduced into other ports. The flow of highly diffusive gases can promote the flow of bubble-causing gases to the vacuum ports. The apparatus and system provide a system in which the gas causing bubble formation can be vented from the sand bed before melting. This system and method for manufacturing hollow quartz cylinders facilitates the production of quartz materials that can be used in semiconductor wafer processing applications (such as etching steps) by reducing the number of bubbles formed during molten quartz.

[0007] This equipment and system allows for control of the atmosphere and conditions within the cylindrical body used to form quartz. Existing systems for forming cylindrical quartz tubes do not allow for atmospheric control. In previous systems, the atmosphere within the sand bed was fixed once the system was sealed. This equipment and system allows for atmospheric control via a series of ports on a rotating cylinder through which a vacuum can be applied and / or process gases can be introduced. In this way, conditions can be created within the cylinder to prevent bubble formation or to reduce bubble size and / or promote bubble escape from the glass during processing.

[0008] In one aspect, a horizontal rotary arc furnace is provided, comprising: a housing defining an interior configured to receive particles for forming a quartz or ceramic body and electrodes for generating a plasma arc, the housing including a plurality of first ports on the exterior of the housing, the first ports being fluidly connected to the interior and supply conduits fluidly connected to the first ports; a support mechanically connecting the housing to a drive system to provide rotational motion to the housing; and a rotary joint connected to the housing, the rotary joint including a second port fluidly connected to a vacuum supply source, the second port being fluidly connected via the supply conduits to at least some of the first ports, wherein the horizontal rotary arc furnace is configured to apply a vacuum to the interior of the housing via the first ports when the housing rotates.

[0009] In one embodiment, the plurality of first ports include a first set of first ports and a second set of first ports, the supply pipes include a first set of supply pipes and a second set of supply pipes, the rotary joint is a first rotary joint, and wherein the horizontal rotary arc furnace further includes a second rotary joint coupled to the housing opposite to the first rotary joint, the second rotary joint including a third port fluidly connected to a gas supply source, the third port being fluidly connected to the second set of first ports via the second set of supply pipes, wherein the second port is fluidly connected to the first set of first ports via the first set of supply pipes.

[0010] In one embodiment, the gas supply source supplies a highly diffusive gas.

[0011] In one embodiment, the highly diffusive gas is a mixture of helium and oxygen, wherein the weight percentage of helium is at least 80%.

[0012] In one embodiment, the gas supply source is configured to supply a highly diffusive gas to the second set of first ports while a vacuum supply source applies a vacuum to the first ports of the first set.

[0013] In one embodiment according to any of the foregoing embodiments, the horizontal rotary electric arc furnace further includes: an axial extension coupled to each end of the housing, wherein the axial extension rotates together with the housing, wherein at least one axial extension is fluidly coupled to a rotary joint and configured to fluidly connect the rotary joint to a supply conduit, wherein the rotary joint provides a seal between a vacuum source and at least one axial extension.

[0014] In one embodiment, the housing includes a cylindrical body for receiving particles and electrodes, wherein an axial extension extends radially away from the cylindrical body, and wherein at least one axial extension is engaged with a drive system within one of the supports to provide rotational force to the housing.

[0015] In one embodiment, the housing includes a cylindrical body that receives particles and electrodes, wherein a first port spaced apart around the cylindrical body supplies a vacuum to the interior of the cylindrical body while maintaining balance to facilitate rotation of the cylindrical body.

[0016] In one embodiment according to any of the foregoing embodiments, each first port includes a plug sufficient to allow vacuuming from the housing or the introduction of highly diffusible gases into the housing, and to prevent particles from entering the first port.

[0017] In one embodiment, the plug is formed of a porous material with sufficient porosity to allow vacuum extraction from the housing while preventing silica particles from entering the first port.

[0018] In another aspect, a method for forming a quartz or ceramic body is provided, comprising: supplying quartz or ceramic particles to a horizontal rotary electric arc furnace according to any of the foregoing embodiments; and while rotating the shell: providing heat to melt at least a portion of the particles into a quartz or ceramic body, and applying a vacuum between the inner wall of the shell and the outer wall of the quartz or ceramic body via a plurality of first ports on the shell.

[0019] In one embodiment, the particles are quartz particles, and the method includes forming a quartz body.

[0020] On the other hand, a method for forming a silica glass body is provided, comprising: supplying silica particles into the interior of a hollow cylindrical body of a horizontally rotating electric arc furnace; and while rotating the hollow cylindrical body: providing heat to melt at least a portion of the silica particles into a silica glass body, and applying a vacuum between the inner wall of the hollow cylindrical body and the outer wall of the silica glass body via one or more ports of a first set on the cylindrical hollow body.

[0021] In one embodiment, the method includes supplying process gas into the interior of the cylinder via one or more ports of a second set on the cylindrical hollow body while rotating the hollow cylindrical body.

[0022] In one embodiment, applying a vacuum and supplying process gas are performed simultaneously.

[0023] In one embodiment, the process gas is a highly diffusive gas.

[0024] In one embodiment, the process gas is a mixture of helium and oxygen, wherein the weight percentage of helium is at least 80%.

[0025] In one embodiment, the method further includes supplying process gas into the interior of the cylinder via one or more ports of a second set on the cylindrical hollow body at a first time while rotating the hollow cylindrical body, wherein a vacuum is applied at a second time and the second time occurs after the first time.

[0026] In one embodiment, the method further includes supplying post-process gas into the interior of the cylinder via one or more ports of a second set at a third time, after the first time, while rotating the hollow cylindrical body. Attached Figure Description

[0027] The operation of this disclosure can be better understood by referring to the following detailed description in conjunction with the following diagrams, wherein:

[0028] Figure 1 This is a perspective view of a rotary electric arc furnace with ports, in accordance with the teachings of this disclosure.

[0029] Figure 2 This is a perspective view of a rotary electric arc furnace assembly in accordance with the teachings of this disclosure. Detailed Implementation

[0030] Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. It should be understood that other embodiments may be employed and structural and functional changes may be made without departing from the corresponding scope of the present disclosure. Furthermore, features of various embodiments may be combined or modified without departing from the scope of the present disclosure. Thus, the following description is presented by way of example only and should not in any way limit the various changes and modifications that may be made to the illustrated embodiments, and such changes and modifications remain within the spirit and scope of the present disclosure.

[0031] As used herein, the words “example” and “exemplary” mean instance or illustration. The words “example” or “exemplary” do not indicate key or preferred aspects or embodiments. Unless the context otherwise specifies, the word “or” is intended to be inclusive rather than exclusive. For example, the phrase “A uses B or C” includes any open permutation (e.g., A uses B; A uses C; or A uses both B and C). On the other hand, unless the context otherwise specifies, the articles “a” and “one” are generally intended to mean “one or more”.

[0032] Semiconductor wafer fabrication for microchip manufacturing requires ordered and repetitive steps, such as masking, deposition, and etching, in addition to other processes. During the etching step, the wafer and the etching chamber are exposed to a corrosive environment (e.g., environments used for reactive ion etching and plasma etching). The innermost etching chamber components are made of quartz glass, allowing etching to result in the dissociation of only silicon and oxygen. These are less harmful to the wafer than transition metals and other elements, which can alter the wafer's composition and thus its semiconductor properties. For suitability for etching, the quartz components should (i) be as chemically purified as possible (e.g., less than 50 parts per million by weight (ppmw) of total impurities) and (ii) have very low concentrations of bulk defects (e.g., foreign inclusions and bubbles). These bulk defects can lead to uneven etching, producing quartz glass particles, when exposed to the etching atmosphere. Loose particulate matter within the etching chamber can clog gates and damage conductive vias on the wafer, or contaminate the wafer with impurity elements.

[0033] The following describes a system and method for reducing air bubbles in a hollow quartz cylinder by controlling the atmosphere within the cylindrical body of a rotary electric arc furnace. To control the atmosphere within the rotary electric arc furnace, the cylindrical body includes ports with porous plugs on the exterior of the cylindrical body. These ports are fluidly connected to manifolds, allowing a vacuum to be drawn into the space between the sand grains after melting on the inner surface of the sand bed. In some examples, two or more sets of ports are fluidly connected to two or more manifolds, respectively. In some such examples, a vacuum is applied to one set of ports and a highly diffusive gas (such as helium or hydrogen) is introduced to another set of ports. This facilitates the control and / or alteration of the atmosphere within the unmelted quartz sand before, during, and / or after melting. The flow of the highly diffusive gas promotes the flow of gas species that cause bubbles to the vacuum ports; thus, the bubbles exit the molten sand bed. In some instances, the ports are flush with the interior of the cylindrical body and include membranes or filters that allow gas flow and / or the application of a vacuum without allowing sand to enter the ports. The ports are distributed in a balanced manner across the cylindrical body to facilitate rotation of the cylindrical body.

[0034] Figure 1 and Figure 2 This is a perspective view of a rotary arc furnace 100 with port 102, which facilitates the control of gas in a sand bed (e.g., silica particles). In the illustrated example, the rotary arc furnace 100 is a horizontal rotary arc furnace in which silica is melted into hollow quartz cylinders. Although the rotary arc furnace 100 is shown as using plasma arc heating, other suitable heating methods, such as resistance heating, may also be used. The rotary arc furnace 100 includes a housing 104 supported by a support member 106. In the illustrated example, the rotary arc furnace 100 is mounted on a machine tool 108 via the support member 106.

[0035] The housing 104 includes a hollow cylindrical body 110 and a furnace flange 112. The cylindrical body 110 includes ports 102 spaced apart around it to supply a vacuum and / or highly diffusive gas to the interior of the cylindrical body 110 while maintaining equilibrium to facilitate rotation of the cylindrical body 110. In some examples, the ports 102 are flush with the interior of the cylindrical body 110. Each port 102 may include a plug sufficient to allow vacuum extraction from the cylinder or the introduction of a highly diffusive gas into the cylinder, wherein the plug prevents or blocks silica particles from entering the port 102 during processing. The plugs may be formed of a porous material with sufficient porosity to satisfy these purposes regarding gas flow and to prevent silica particles from escaping the tube and clogging the port. There are no particular limitations on the material used for the plugs, and they can be selected as needed. In one embodiment, the plug is made of a refractory material, alloy, steel, or stainless steel. In some examples, port 102 facilitates the introduction of gas into the interior of the cylindrical body 110 (e.g., in the space between the interior of the cylindrical body 110 and the molten hollow quartz cylinder).

[0036] Each furnace flange 112 includes a flange body 113, a refractory member 114 supporting a cylindrical body 110, and an axial extension 116 that engages with a drive system 118 within a corresponding support member 106. Each refractory member 114 extends radially into the interior of the cylindrical body 110. In the illustrated example, the outer diameter of the refractory member 114 is configured to match the inner diameter of the cylindrical body 110. Each refractory member 114 defines an aperture along a horizontal central axis through which an electrode 119 and / or silica particles can be introduced. The axial extension 116 extends radially away from the cylindrical body 110 to engage with the drive system 118 within a corresponding support member 106, thereby providing rotational force to the housing 104. The axial extension 116 defines an aperture coaxial with the aperture defined by the corresponding refractory member 114, thereby providing access to the interior of the cylindrical body 110 for the electrode 119 and / or silica particles.

[0037] Each axial extension 116 is coupled to a rotary joint 120, which provides a seal between a stationary gas supply and / or vacuum source and the rotating axial extension 116. The rotary joint 120 includes a supply port 122. In some instances, one of the rotary joints 116 may be fluidly coupled to a vacuum source, while another of the rotary joints 116 may be fluidly coupled to one or more gas supply sources. The axial extension 116 is fluidly coupled to the corresponding rotary joint 120 and configured to fluidly connect the rotary joint 120 to a supply conduit 124, which fluidly connects the axial extension 116 to a flange body 113. The flange body 113 defines a passage corresponding to the supply conduit 124, such that the flange body 113 is fluidly connected to the vacuum source and / or one or more gas supply sources via the corresponding axial extension 116 and the corresponding rotary joint 120. The passage defined in the flange body 113 is fluidly coupled to a port 102 for supplying vacuum and / or gas to the interior of the cylindrical body 110. In this way, when the housing 104 rotates, a vacuum can be applied to the radially outer side of the molten silica forming the hollow quartz cylinder to facilitate the exit of any bubbles formed in the molten silica via the radially outer side of the molten silica.

[0038] Figure 2 A rotary arc furnace 100 is shown within a component housing 200. A feeding system (e.g., a pneumatic feeding system, etc.) delivers silica particles from a hopper 202 through a feed pipe 204 into the interior of the rotary arc furnace 100. An arc system 206 provides electrodes 119 to the interior of the rotary arc furnace 100. In operation, a plasma arc is established between the electrodes 119 to provide heat to melt the silica particles into fused silica. In the illustrated example, the hopper 202 and the arc system 206 are situated on a platform 208 movable on a track 210. The platform 208 and the track 210 are configured to move to interchange whether the feed pipe 204 or the electrodes 119 are inside the rotary arc furnace 100. In some instances, one or more platforms 208 move perpendicular to the track to interchange whether the feed pipe 204 or the electrodes 119 are inside the rotary arc furnace 100.

[0039] In operation, silica particles are introduced into the interior of the rotating cylindrical body 110 (e.g., via hopper 202 and feed pipe 204, etc.). Electrodes 119 are introduced into the interior of the cylindrical body 110. In some examples, a highly diffusive gas (e.g., a mixture of helium, hydrogen, helium, and oxygen, of which at least 80% by weight is helium, etc.) (sometimes referred to as a "process gas") is introduced into the interior of the cylindrical body 110 via port 102. The housing 104 rotates, causing the silica particles to adhere to the inner wall of the cylindrical body 110. An electric arc is generated between the electrodes 119. The electrodes 119 are then moved apart to their operating positions, with the plasma arc between the electrodes. The arc heats the silica particles, gradually transforming them into a molten state. The layer of silica particles closest to the arc melts first, with the melting front gradually extending outward toward the inner wall of the cylindrical body 110. After the inner surface of the quartz melts, a vacuum is drawn in the remaining silica layer. A thin layer of unmelted silica particles remains between the molten silica and the inner wall of the cylindrical body 110, remaining unmelted throughout the remaining processing. In some examples, a highly diffusive gas (sometimes referred to as a "post-process gas") is introduced into the interior of the cylindrical body 110, such that some ports 102 are evacuated while others are supplied with the post-process gas. In some examples, the post-process gas may be a different gas or a mixture of gases than the process gas. In such examples, the flow of the highly diffusive gas can facilitate the flow of gas species that cause bubbles to the vacuum ports.

[0040] It should be understood that this system allows or is capable of accommodating pipes of varying lengths. Figure 2 In the example shown, the component housing 200 includes an adjustable wall 212. The adjustable wall 212 and the corresponding support 106 can be horizontally adjusted to accommodate hollow cylindrical bodies 110 of different lengths and / or different port configurations. In this way, a hollow cylindrical body 110 of one length can be removed and replaced with a hollow cylindrical body 110 of a different length.

[0041] The apparatus, including a cylinder with ports, allows control of the environment within the system. In the production of cylindrical silica glass bodies, various processing conditions related to the vacuum applied to the system and / or the flow of process gases through the system via the ports can be selected, depending on the specific purpose or intended application. This system and apparatus allow simultaneous evacuation at different locations along the length of the rotating cylinder (including opposite ends of the cylinder). In one embodiment, the system is configured to simultaneously evacuate within the system and introduce process gases into the system. In another embodiment, the introduction of process gases and evacuation occur at different times.

[0042] The device and system also allow for the introduction of different process gases at selected times. In one embodiment, helium is introduced as a process gas for a selected period of time, and once the silicon dioxide begins to glassy, ​​the flow of helium is stopped, and argon is introduced into the system. It should also be understood that systems with various ports allow for the introduction of mixtures of process gases at desired ratios, for example, by controlling the flow rates of the various gases through the ports.

[0043] The number of ports on a cylinder is generally unlimited and can be selected based on specific purposes or the need to provide specific conditions or characteristics within the cylinder. The number of ports can affect how the atmosphere within the system is controlled. A greater number of ports allows for more options in controlling / generating the atmosphere within the cylinder. For example, the number and location of ports will help determine where a vacuum is applied or where process gases are introduced into the cylinder. For instance, by increasing the number of ports per unit area, a certain level of vacuum can be applied along the length of the cylinder and the silica bed.

[0044] In one embodiment, a port along the first half of the cylinder's length is connected to apply a vacuum to the system, and a port along the second half of the cylinder's length is connected to supply process gas. The gas pressure or flow rate can be controlled as needed.

[0045] The apparatus and methods described herein are applicable to the formation of useful tubes in a variety of applications, including but not limited to the semiconductor industry. The apparatus and system can be used to manufacture quartz glass cylinders of selected thicknesses. In embodiments, the quartz cylinder may have a thickness of approximately 1 cm to approximately 10 cm and an outer diameter of approximately 15 cm to approximately 50 cm.

[0046] The type and properties of the starting feed material used in this process can be selected according to the needs of a specific purpose or intended application. For manufacturing quartz cylinders, the starting material is silica (SiO2) sand. The silica (SiO2) used in the glass composition of this embodiment can be synthetic sand, natural sand, or a mixture thereof. In one embodiment, the amount of SiO2 in the glass composition ranges from about 82% to about 99.9999%. In another embodiment, the amount of SiO2 in the glass composition is about 92% to about 99.9999%; about 96% to about 99.9999 wt%; about 97% to about 99.9999 wt%; or even about 98% to about 99 wt%. As elsewhere in the specification and claims, ranges can be combined to form new and non-specific ranges. The feed material may also include recycled or broken glass material (also referred to as cullet).

[0047] Furthermore, although the apparatus and system have been described for the manufacture of quartz cylinders, it should be understood that the apparatus and system can be adapted and used to manufacture cylinders of other materials, including but not limited to ceramic or glass-ceramic materials. Ceramic materials may include alumina, zirconium oxide, barium oxide, silicon carbide, silicon nitride, boron nitride, beryllium oxide, titanium dioxide, calcium oxide, magnesium oxide, and combinations of two or more of these. Glass-ceramics may include mixtures of ceramic and silica particles.

[0048] Although embodiments of the invention have been shown in the accompanying drawings and described in the foregoing detailed description, it should be understood that this disclosure is not limited to the disclosed embodiments, but rather that various rearrangements, modifications, and substitutions are possible without departing from the scope of the following claims. The appended claims are intended to cover all modifications and substitutions, provided they fall within the scope of the claims or their equivalents.

Claims

1. A horizontally rotating electric arc furnace, comprising: A defined internal housing is configured to receive particles for forming a quartz or ceramic body and electrodes for generating a plasma arc, the housing including a plurality of first ports fluidly connected to the interior on the sidewalls of the housing and supply conduits fluidly connected to the first ports. A support member that mechanically connects the housing to a drive system to provide rotational motion to the housing; as well as A first rotary joint is coupled to the housing, the first rotary joint including a second port fluidly connected to a vacuum supply source, the second port being fluidly connected via a supply conduit to at least some of the first ports. The horizontal rotary electric arc furnace is configured to apply a vacuum between the inner surface of the sidewall of the shell and the outer wall of the quartz or ceramic body via the first port when the shell rotates.

2. The horizontal rotary electric arc furnace according to claim 1, wherein... The plurality of first ports includes a first group of first ports and a second group of first ports. The supply pipeline includes a first set of supply pipelines and a second set of supply pipelines. in, The horizontal rotary electric arc furnace further includes a second rotary joint connected to the housing and opposite to the first rotary joint. The second rotary joint includes a third port fluidly connected to a gas supply source. The third port is fluidly connected to a second set of first ports via a second set of supply pipes, wherein the second port is fluidly connected to a first set of first ports via a first set of supply pipes.

3. The horizontal rotary electric arc furnace according to claim 2, wherein, The gas supply source supplies highly diffusive gas.

4. The horizontal rotary electric arc furnace according to claim 3, wherein, The highly diffusive gas is a mixture of helium and oxygen, wherein the weight percentage of helium is at least 80%.

5. The horizontal rotary electric arc furnace according to claim 2, wherein, The gas supply source is configured to supply highly diffusible gas to the second group of first ports while the vacuum supply source applies a vacuum to the first ports of the first group.

6. The horizontal rotary electric arc furnace according to any one of claims 1-5, further comprising: An axial extension is attached to each end of the housing, wherein the axial extension rotates together with the housing. At least one axial extension is fluidly connected to a first or second rotary joint and is configured to fluidly connect the first or second rotary joint to a supply conduit. The rotary joint provides a seal between the vacuum source and at least one axial extension.

7. The horizontal rotary electric arc furnace according to claim 6, wherein, The housing includes a cylindrical body for receiving particles and electrodes, wherein the axial extension extends radially away from the cylindrical body, and wherein at least one axial extension is connected to a drive system within one of the supports to provide rotational force to the housing.

8. The horizontal rotary electric arc furnace according to claim 1, wherein, The housing includes a cylindrical body for receiving particles and electrodes, wherein the first port is spaced apart around the cylindrical body to supply a vacuum to the interior of the cylindrical body while maintaining balance to facilitate rotation of the cylindrical body.

9. The horizontal rotary electric arc furnace according to claim 1, wherein, Each of the first ports includes a plug sufficient to allow a vacuum to be drawn from the housing or to introduce a highly diffusible gas into the housing, and to prevent particles from entering the first port.

10. The horizontal rotary electric arc furnace according to claim 9, wherein, The plug is formed of a porous material with sufficient porosity to allow a vacuum to be drawn from the housing while preventing silica particles from entering the first port.

11. A method for forming a silica glass, comprising: Silica particles are supplied into the interior of the hollow cylindrical body of the horizontal rotary electric arc furnace; as well as While the hollow cylindrical body is rotating: Heat is provided to melt at least a portion of the silica particles into a silica glass, and A vacuum is applied between the inner surface of the sidewall of the hollow cylindrical body and the outer wall of the silica glass body via one or more ports of the first set on the sidewall of the hollow cylindrical body.

12. The method of claim 11, further comprising supplying process gas into the interior of the cylinder via one or more ports of a second set on the hollow cylinder body while rotating the hollow cylinder body.

13. The method according to claim 12, wherein, Applying a vacuum and supplying process gas are done simultaneously.

14. The method according to claim 12, wherein, The process gas is a highly diffusive gas.

15. The method according to claim 14, wherein, The process gas is a mixture of helium and oxygen, wherein the weight percentage of helium is at least 80%.

16. The method of claim 12, further comprising, while rotating the hollow cylindrical body, supplying process gas to the interior of the cylinder via one or more ports of a second set on the hollow cylindrical body at a first instant, wherein, The vacuum is applied at the second time, which occurs after the first time.

17. The method of claim 16, further comprising, while rotating the hollow cylindrical body, supplying post-process gas into the interior of the cylinder via one or more ports of a second set at a third time, the third time being after the first time.

18. A method for forming a quartz or ceramic body, comprising: Supplying quartz or ceramic particles to the horizontal rotary electric arc furnace according to any one of claims 1-10; as well as While the shell is rotating: Provide heat to melt at least a portion of the particles into a quartz or ceramic body, and A vacuum is applied between the inner wall of the housing and the outer wall of the quartz or ceramic body via multiple first ports on the housing.

19. The method according to claim 18, wherein, The particles are quartz particles, and the method includes forming a quartz body.

Images