AND A GASKET FOR USE THEREIN

RELATED APPLICATIONS

[0001] This application claims priority to and all advantages of United States Provisional Patent Application No. 61/792,528, filed on March 15, 2013, the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a manufacturing apparatus for depositing a material on a carrier body. More specifically, the present invention relates to a gasket used to seal a chamber of the manufacturing apparatus.

BACKGROUND OF THE INVENTION

[0003] Manufacturing apparatuses for depositing a material on a carrier body are known in the art. For example, silicon may be deposited on the carrier body to produce polycrystalline silicon. A conventional manufacturing apparatus includes a housing defining a chamber. The carrier body is placed in the chamber before the conventional manufacturing apparatus is operated. During operation of the conventional manufacturing apparatus, the carrier body is heated in the presence of a deposition composition, which contains the material. The deposition composition is decomposed, which results in the deposition of the material on the carrier body.

[0004] The conventional manufacturing apparatus includes a gasket for sealing the chamber. Sealing the chamber maintains an operating pressure of the chamber. Additionally, sealing the chamber also prevents the deposition composition from escaping the chamber. However, as the carrier body is heated, the gasket is also heated, which degrades the gasket over time. As the gasket degrades, the gasket fails to seal the chamber. Furthermore, as the gasket is heated, the gasket may release impurities into the chamber, which can contaminate the material deposited on the carrier body. Therefore, the gasket must be capable of maintaining the seal at high temperatures while limiting degrading of the gasket and limiting contamination of the material deposited on the carrier body. SUMMARY OF THE INVENTION AND ADVANTAGES

[0005] A gasket seals a chamber of a manufacturing apparatus. The manufacturing apparatus deposits a material on a carrier body. The manufacturing apparatus includes a housing defining the chamber. The housing also includes a jar and a base plate for coupling with the jar. An electrode is disposed through the housing with the electrode at least partially disposed within the chamber. The housing defines an inlet for introducing a deposition composition, which comprises the material or a precursor thereof, into the chamber. The gasket comprises a body portion defining an upper groove for positioning adjacent the jar. The body portion also defines a lower groove opposite said upper groove for positioning adjacent the base plate. A first sealing element is disposed within said upper groove for sealing against the jar. A second sealing element is disposed within said lower groove for sealing against the base plate. The first and second sealing elements seal between the jar and the base plate to prevent the deposition composition from escaping the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0007] Figure 1 is a cross-sectional view of a manufacturing apparatus for depositing a material on a carrier body including a gasket;

[0008] Figure 2 is a cross-sectional view of a portion of the manufacturing apparatus showing the gasket disposed within a channel defined by a base plate;

[0009] Figure 3 is a cross-sectional view of a portion of the manufacturing apparatus showing the gasket disposed between ajar and the base plate;

[0010] Figure 4 is a cross-sectional view of a portion of the manufacturing apparatus showing the gasket disposed between a flange of the jar and the base plate;

[0011] Figure 5 is a perspective view of a portion of the gasket;

[0012] Figure 6 is a cross-sectional view of the gasket taken along line 6-6 of Figure 6;

[0013] Figure 7 is a cross-sectional view of an alternative embodiment of the gaskets, which includes a sealing lip; [0014] Figure 8 is a cross-sectional view of an alternative embodiment of the gasket, which includes a gasket segment interconnecting an first and second sealing element;

[0015] Figure 9 is a cross-sectional view of a portion of the manufacturing apparatus showing the gasket including fins;

[0016] Figure 10 is a perspective view of a portion of the gasket of Figure 9, which has the fins;

[0017] Figure 11 is a cross-sectional view of a portion of the manufacturing apparatus showing the gasket defining a first and second upper groove and a first and second lower groove; and

[0018] Figure 12 is a perspective view of a portion of the gasket of Figure 11, which has the first and second upper grooves and the first and second lower grooves.

DETAILED DESCRIPTION OF THE INVENTION

[0019] Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a manufacturing apparatus 20 for deposition of a material 22 on a carrier body 24 is shown. During operation of the manufacturing apparatus 20, the material 22 is deposited on a carrier body 24. For example, the manufacturing apparatus 20 may be a chemical vapor deposition reactor, such as a Siemens type chemical vapor deposition reactor, for depositing silicon on the carrier body 24 to produce high purity polycrystalline silicon. As is known with the Siemens Method, the carrier body 24 may have a substantially U-shaped configuration. However, it is to be appreciated that the carrier body 24 may have configurations other than the U-shaped configuration. Additionally, when the material 22 to be deposited is silicon, the carrier body 24 is typically a silicon slim rod comprising high purity silicon. The silicon is deposited on the silicon slim rod for producing high purity polycrystalline silicon.

[0020] With reference to Figure 1, the manufacturing apparatus 20 comprises a housing 26. The housing 26 defines a chamber 28. The housing 26 includes a jar 30 and a base plate 32 for coupling to the jar 30 to form the housing 26. The jar 30 of the housing 26 has at least one wall 34 with the wall 34 typically presenting a cylindrical configuration of the housing 26. However, it is to be appreciated that the jar 30 of the housing 26 may have configurations other than cylindrical, such as a cubed configuration.

[0021] As alluded to above, the housing 26 defines the chamber 28. More specifically, the jar 30 of the housing 26 defines a chamber 28. Even more specifically, the wall 34 of the jar 30 of the housing 26 has an interior surface, such that the interior surface of the jar 30 defines the chamber 28. The jar 30 has an end that is open for allowing access to the chamber 28. The base plate 32 is coupled to the end of the jar 30 that is open for covering the end. When coupled to the jar 30, the base plate 32 partially seals the chamber 28. However, the mechanical interaction between the jar 30 and the base plate 32 is not sufficient to completely seal the chamber 28. As such, a gasket 36 may be disposed between the jar 30 and the base plate 32 for sealing the chamber 28 at the wall 34 of the jar 30. The gasket 36 is described in greater detail below.

[0022] As best shown in Figure 2, the housing 26 may include a flange 38, which extends from the wall 34 of the housing 26. More specifically, the flange 38 extends transversely from the wall 34 of the housing 26. Typically, the flange 38 is parallel with the base plate 32 when the base plate 32 is coupled to the housing 26. Typically, both the flange 38 and the base plate 32 define a hole 40 for receiving a fastener 42, such as a bolt, to secure the jar 30 to the base plate 32. Said differently, the fastener 42 prevents the jar 30 and the base plate 32 from moving relative to each other. It is to be appreciated that the hole 40 in the flange 38 and the base plate 32 may be threaded for receiving threads of the fastener 42.

[0023] The base plate 32 may define a channel 44. The channel 44 is defined about a periphery of the base plate 32. Additionally, the flange 38 of the housing 26 may have a finger 46 extending from the flange 38 for engaging the channel 44 of the base plate 32. The engagement of the finger 46 of the flange 38 with the channel 44 of the base plate 32 ensures that the base plate 32 and the housing 26 are properly aligned when coupling the housing 26 to the base plate 32. The engagement of the finger 46 of the flange 38 with the channel 44 of the base plate 32 also prevents a blowout of the wall 34 of the jar 30 during operation of the manufacturing apparatus 20.

[0024] Referring back to Figure 1, the housing 26 defines an inlet 48 for introducing a deposition composition 49, which comprises the material 22 to be deposited or a precursor thereof, into the chamber 28. Similarly, the housing 26 may define an outlet 50 for allowing the deposition composition 49, or a reaction byproduct thereof, to be exhausted from the chamber 28. It is to be appreciated that the inlet 48 and/or the outlet 50 may be defined by either the jar 30 or the base plate 32 of the housing 26. Typically, an inlet pipe 52 is connected to the inlet 48 for delivering the deposition composition 49 to the chamber 28 and an exhaust pipe 54 is connected to the outlet 50 for removing the deposition composition 49, or a reaction byproduct thereof, from the chamber 28.

[0025] The manufacturing apparatus 20 includes an electrode 56 disposed through the housing 26. The electrode 56 is at least partially disposed within the chamber 28. For example, the electrode 56 is typically disposed through the base plate 32 with a portion of the electrode 56 supporting the carrier body 24 within the chamber 28. However, it is to be appreciated that the electrode 56 may be disposed through the jar 30 of the housing 26. Typically, the electrode 56 comprises an electrically conductive material 22 such as copper, silver, nickel, Inconel, gold, and combinations thereof. The electrode 56 is heated within the chamber 28 by passing an electric current through the electrode 56. As a result of passing the electric current from the electrode 56 to the carrier body 24, the carrier body 24 is heated to a deposition temperature by a process known as Joule heating. Typically, the deposition temperature of the carrier body 24 within the chamber 28 is of from about 800 to about 1,250, more typically of from about 900 to about 1,150, and even more typically of from about 950 to about 1,100 degrees centigrade.

[0026] The Joule heating of the carrier body 24 to the deposition temperature results in a radiant/convective heating of the chamber 28. As such, during operation of the manufacturing apparatus 20, an operating temperature of the chamber 28 is of from about room temperature to about 400, more typically of from about 150 to about 350, and even more typically of from about 150 to about 350 degrees centigrade. It is to be appreciated that the operation temperature is not constant during operation of the manufacturing apparatus 20 and the operating temperature generally increases during operation.

[0027] Heating the carrier body 24 to the deposition temperature generally facilitates thermal decomposition of the deposition composition 49. As alluded to above, the deposition composition 49 comprises the material 22 to be deposited on the carrier body 24 or a precursor thereof. Therefore, the thermal decomposition of the deposition composition 49 results in the material 22 being deposited on the heated carrier body 24. For example, when the material 22 to be deposited is silicon, the deposition composition 49 may comprise a halosilane, such as a chlorosilane or a bromosilane. However, it is to be appreciated that the deposition composition 49 may comprise other precursors, especially silicon containing molecules such as silane, silicon tetrachloride, tribromosilane, and trichlorosilane. It is also to be appreciated that the manufacturing apparatus 20 can be used to deposit materials other than silicon on the carrier body 24.

[0028] Generally, it is beneficial to prevent impurities from contaminating the material 22. An impurity or impurities, as the terms are generally used herein, are defined as an element or a compound the presence of which is undesirable in the material 22 deposited. For example, when the material 22 to be deposited is silicon, the impurities of concern typically include aluminum, arsenic, boron, phosphorous, iron, nickel, copper, chromium, and combinations thereof. Generally, limiting impurities present in the material 22 deposited on the carrier body 24 results in a high purity of the material 22. High purity, as the term is used herein, means that the material 22 has an impurity content of less than or equal to 1 parts per million atomic. However, it is to be appreciated that when the material 22 to be deposited is silicon, there are additional distinctions between deposited silicons, which can be made based on sequentially lower impurity contents. While the above threshold for characterizing the material 22 as having a high purity provides an upper limit for the impurity content, deposited silicons can still be characterized as high purity with substantially lower impurity content than the threshold set forth above.

[0029] As described above, the manufacturing apparatus 20 includes the gasket 36. It is to be appreciated that the gasket 36 may be referred to as a seal. The gasket 36 is disposed between the jar 30 and the base plate 32 for sealing the chamber 28 at the wall 34 of the jar 30, as shown in Figure 2. Generally, the gasket 36 is disposed between the jar 30 and the base plate 32 for preventing the deposition composition 49 from escaping the chamber 28. For example, when the deposition composition 49 comprises trichlorosilane, the deposition composition 49 is a gas and the gasket 36 prevents the trichlorosilane from escaping the chamber 28.

[0030] When the gasket 36 is disposed between the jar 30 and the base plate 32, the gasket 36 may be disposed between the wall 34 of the jar 30 and the base plate 32, as shown in Figure 3. In such an embodiment, the wall 34 of the jar 30 contacts the gasket 36 to compress the gasket 36 for sealing between the housing 26 and the base plate 32. Additionally, when the gasket 36 and the flange 38 are present, the gasket 36 may be disposed between the flange 38 and the base plate 32 to seal the perimeter of the base plate 32 about the jar 30, as shown in Figure 4. In such an embodiment, the flange 38 contacts the gasket 36 to compress the gasket 36 for sealing between the housing 26 and the base plate 32. Furthermore, when the gasket 36 and the flange 38 are present, the gasket 36 may be disposed within the channel 44 of the base plate 32 with the finger 46 contacting the gasket 36 to compress the gasket 36 for sealing between the jar 30 and the base plate 32, as shown in Figure 2.

[0031] During operation of the manufacturing apparatus 20, pressure within the chamber 28 may increase to an operating pressure. Although pressure within the chamber 28 may reach the operating pressure, the gasket 36 is capable of sealing between the housing 26 and the base plate 32. As such, sealing the chamber 28 with the gasket 36 assists with maintaining the operating pressure within the chamber 28. Typically, the operating pressure is less than of from about 15, more typically of from about 2 to about 8, and even more typically of from about 3 to about 7 atmospheres. It is to be appreciated that the engagement of the finger 46 with the channel 44 prevents a side blowout of the reactor chamber 28. For example, when the gasket 36 is disposed between the jar 30 and the base plate 32, the engagement of the finger 46 and the channel 44 prevents the gasket 36 from rupturing as pressure within the chamber 28 increases. Furthermore, the engagement of the finger 46 with the channel 44 allows the gasket 36 to be thinner relative to conventional gaskets.

[0032] Generally, the gasket 36 is in atmospheric communication with the chamber 28. As such, the gasket 36 is heated as the temperature within the chamber 28 approaches the operating temperature. Additionally, the gasket 36 is in atmospheric communication with the carrier body 24 within the chamber 28 and is therefore in atmospheric communication with the material 22 as it is deposited on the carrier body 24. Therefore, care must be taken to ensure that the gasket 36 does not contribute impurities into the chamber 28, especially when the gasket 36 is heated. As such, the gasket 36 has a thermal stability suitable to prevent decomposition, which can result in an introduction of impurities into the chamber 28, when the gasket 36 is exposed to the operating temperature within the chamber 28. Therefore, due to the thermal stability of the gasket 36, the gasket 36 minimally contributes impurities, if at all, into the chamber 28 during operation of the manufacturing apparatus 20.

[0033] Typically, when the material 22 deposited on the carrier body 24 is to be high purity, the gasket 36 contributes an amount of impurities to the material 22 deposited on the carrier body 24 that is less than 100 parts per billion atomic. Therefore, the gasket 36 can be used within the manufacturing apparatus 20, which deposits the material 22 having the high purity. For example, when the material 22 deposited is silicon for producing polycrystalline silicon, the polycrystalline silicon is produced with the high purity because possible contamination by the gasket 36 has been limited or even eliminated. The limitation or prevention of impurities within the gasket 36 from contaminating the material 22 deposited on the carrier body 24 allows the material 22 deposited on the carrier body 24, especially polycrystalline silicon, to meet and/or exceed the high purity threshold described above.

[0034] With reference to Figures 5 and 6, the gasket 36 comprises a body portion 58. Generally, the gasket 36 has a ring shaped configuration for sealing the perimeter of the base plate 32 at the jar 30. As such, the body portion 58 of the gasket 36 is ring shaped. The gasket 36 has a diameter. The diameter of the gasket 36 can vary to accommodate various sizes of the base plate 32 or various sizes of the electrode 56. More specifically, the when the gasket 36 is disposed between the jar 30 and the base plate 32, the diameter of the gasket 36 can be adjusted to a diameter of the wall 34 of the jar 30 to ensure the gasket 36 is properly seated between the wall 34 of the jar 30 and the base plate 32.

[0035] Typically, the body portion 58 of the gasket 36 comprises a metal material. It is to be appreciated that any suitable metal material may be used. For example, the metal material may be selected from the group of inconel 600, inconel 800, incalloy, hastalloy, nickel 200, sliver, and combinations thereof. More typically, the body portion 58 of the gasket 36 comprises inconel 600.

[0036] The body portion 58 defines an upper groove 64 adjacent the jar 30. The body portion 58 also defines a lower groove 66 opposite the upper groove 64 and adjacent the base plate 32. The gasket 36 includes a first sealing element 68 disposed within the upper groove 64. The gasket 36 also includes a second sealing element 70 disposed within the lower groove 66. It is to be appreciated that the sealing elements 68, 70 may be held within the upper and lower grooves 64, 66 by any suitable method. For example, the sealing elements 68, 70 may be press fit into the upper and lower grooves 64, 66. Furthermore, an adhesive may be used to bond the sealing elements 68, 70 within the upper and lower grooves 64, 66.

[0037] The first and second sealing elements 68, 70 seal against either the jar 30 or the base plate 32 to seal the chamber 28. More specifically, the first sealing element 68 seals against the jar 30 and the second sealing element 70 seals against the base plate 32. It is to be appreciated that the sealing elements 68, 70 may be used to seal against other surfaced of the manufacturing apparatus 20 besides the jar 30 and the base plate 32. For example, when present, the first sealing element 68 may seal against the flange 38 of the jar 30. Alternatively, the first sealing element 68 may seal against the wall 34 of the jar 30.

[0038] The first and second sealing elements 68, 70 may be removable from the body portion 58 of the gasket 36 for allowing easy replacement of either one of the first and second sealing elements 68, 70 independent from each other. Said differently, the first sealing element 68 may be replaced while the second sealing element 70 is reused. Additionally, the body portion 58 of the gasket 36 prevents the first and second sealing elements 68, 70 from being deformed or damaged when the housing 26 is separated from the base plate 32. Deforming or damaging the first and second sealing elements 68, 70 can lead to the chamber 28 not reaching the operating pressure and purity issues.

[0039] Typically, each of the sealing elements 68, 70 has an inner wall 72 abutting the body portion 58 within a respective one of the upper or lower grooves 64, 66. The sealing elements 68, 70 also have and an outer wall 74 spaced from the inner wall 72. The outer wall 74 of the sealing elements 68, 70 abut the body portion 58 within the upper and lower grooves 64, 66.

[0040] The sealing elements 68, 70 may have any suitable cross-sectional configuration. For example, the sealing elements 68, 70 may have a semi-circular cross-section, as shown in Figure 6. Alternatively, as shown in Figure 7, the sealing elements 68, 70 may include a sealing lip 80 disposed between the inner and outer walls 72, 74 for sealing against either the jar 30 or the base plate 32. The sealing lip 80 extends from the gasket 36 to ensure either the jar 30 or the base plate 32 contacts the lip directly to compress the sealing lip 80 to ensure a proper seal of the chamber 28 is formed. The sealing elements 68, 70 may have a pair of furrows 82 separated by the sealing lip 80 such that the sealing elements 68, 70 have a W-shaped configuration in cross- section.

[0041] The first and second sealing elements 68, 70 may comprise an elastomeric material. Generally, the elastomeric has a high purity and is resilient. The elastomeric material provides the sealing elements 68, 70 with flexibility. Providing the sealing elements 68, 70 with flexibility allows the sealing elements 68, 70 to seal against uneven surfaces of either the electrode 56 or the base plate 32 of the housing 26. [0042] Typically, the elastomeric material is selected from the group of perfluoro rubber, perfluoroelastomer, resilient metal-based materials, silicone or other organic elastomers, and combinations thereof. Additionally, the first and second sealing elements 68, 70 may comprise a flexible graphite material, such as Grafoil®, which is commercially available from GrafTech International.

[0043] As described above, care must be taken to ensure that the gasket 36 does not contribute impurities into the chamber 28. As such, the sealing elements 68, 70 and the body portion 58 of the gasket 36 have a thermal stability suitable to prevent decomposition, which can result in an introduction of impurities into the chamber 28, when the gasket 36 is exposed to the operating temperature within the chamber 28. Therefore, due to the thermal stability of the sealing elements 68, 70 and the body portion 58 of the gasket 36, the gasket 36 minimally contributes impurities, if at all, into the chamber 28 during operation of the manufacturing apparatus 20.

[0044] Generally, the elastomeric material of the sealing elements 68, 70 contribute less than about 50 parts per million atomic of Boron and/or Phosphorous to the material 22 deposited on the carrier body 24. Therefore, the gasket 36 can be used within the manufacturing apparatus 20, which deposits the material 22 having the high purity. For example, when the material 22 deposited is silicon for producing polycrystalline silicon, the polycrystalline silicon is produced with the high purity because possible contamination by the gasket 36 has been limited or even eliminated.

[0045] The limitation or prevention of impurities within the gasket 36 from contaminating the material 22 deposited on the carrier body 24 allows the material 22 deposited on the carrier body 24, especially polycrystalline silicon, to meet and/or exceed the high purity threshold described above. Additionally, the limitation or prevention of impurities from the gasket 36 contaminating the material 22 deposited on the carrier body 24 may be accomplished despite the fact that the manufacturing apparatus 20 is not equipped with cooling devices for reducing the heating of the gasket 36.

[0046] As shown in Figure 8, the gasket 36 may include a plurality of gasket segments 76 interconnecting the first and second sealing elements 68, 70. Said differently, the gasket segments 76 may extend through the body portion 58 of the gasket 36 to couple the first sealing element 68 to the second sealing element 70. As such, the body portion 58 of the gasket 36 defines a plurality of channels 78 extending between the first and second sealing elements 68, 70 with the gasket segments 76 disposed within the channels 78 for interconnecting the first and second sealing elements 68, 70. It is to be appreciated that the gasket segments 76 may be spaced about the circumference of the gasket 36 such that the gasket segments 76 are spaced from each other.

[0047] As shown in Figures 9 and 10, the body portion 58 of the gasket 36 may comprise a plurality of fins 60 extending form the body portion 58 for cooling the gasket 36. Said differently, the body portion 58 may define a plurality of cooling recesses 62 between the fins 60. The cooling recesses 62 and fins 60 provide the body portion 58 with an increased surface area. A coolant, such as air, is circulated in the cooling recesses 62 for removing heat from the body portion 58 to cool the gasket 36. Cooling the gasket 36 allows the use of parafluor and other elastomeric materials. As such, the gasket 36 can comprise the elastomeric material without melting when exposed to the operating temperature.

[0048] As shown in Figures 11 and 12, the body portion 58 may include more than one of the upper groove 64 and more than one of the lower groove 66 for receiving multiple sealing elements 68, 70. For example, the body portion 58 may define a first upper groove 64A and a second upper groove 64B spaced from the first upper groove 64A. The first upper groove 64A receives one of the first sealing elements 68 and the second upper groove 64B receives another one of the first sealing elements 68. Likewise, the body portion may define a first lower groove 66A and a second lower groove 66B spaced from the first lower groove 66A. The first lower groove 66A receives one of the second sealing elements 70 and the second lower groove 66B receives another one of the second sealing elements 70.

[0049] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The foregoing invention has been described in accordance with the relevant legal standards; thus, the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of legal protection afforded this invention may only be determined by studying the following claims.