Vertical batch furnace assembly with cooling gas supply

Abstract

To provide a vertical batch furnace assembly comprising a cooling gas supply.SOLUTION: A vertical batch furnace assembly 10 comprises a core tube 12, an outer casing 16, a cooling chamber bounded and enclosed by the outer casing and the core tube, and at least one cooling gas supply emitting into the cooling chamber. The core tube 12 has an elongated circumferential wall 14 extending in a longitudinal direction, and is configured to accommodate wafers for processing in the vertical batch furnace. The outer casing 16 extends around the core tube and comprises a heating element 18 for applying thermal treatment to wafers accommodated in the core tube. The at least one cooling gas supply comprises at least one cooling gas supply opening 26 which is arranged such that the cooling gas enters the cooling chamber in a flow direction which is substantially tangent to the circumferential wall.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure generally relates to a vertical batch furnace assembly with a cooling gas supply. [Background technology]

[0002] Most vertical batch furnaces include a core tube configured to house the wafers being processed in the vertical batch furnace. During processing in the vertical batch furnace, the wafers and the core tube may become hot. To speed up the throughput of the vertical batch furnace assembly, the core tube may be cooled. Cooling gas may be supplied through several circumferentially spaced openings in the lateral sides of a cooling chamber between the circumferential wall of the core tube and the outer casing. Summary of the Invention [Means for solving the problem]

[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are described in more detail below in the Detailed Description of exemplary embodiments of this disclosure. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0004] It may be realized that the circumferentially spaced openings may locally create cold spots on the circumferential wall of the core tube. Such cold spots may cause temperature differences within the circumferential wall, which may result in stresses within the circumferential wall. Furthermore, wafers inside the core tube may be exposed to temperature differences that may result in breakage of the wafers.

[0005] It may therefore be an object to provide a vertical batch furnace assembly that can alleviate the above-mentioned problems.

[0006] To that end, a vertical batch furnace assembly as set forth in claim 1 may be provided. More specifically, the vertical batch furnace assembly may include a core tube, an outer casing, a cooling chamber bounded and enclosed by the outer casing and the core tube, and at least one cooling gas supply radiating into the cooling chamber. The core tube may have an elongated circumferential wall extending in a longitudinal direction, and the core tube may be configured to accommodate wafers for processing in the vertical batch furnace. The outer casing may extend around the core tube and may include a heating element for applying a heat treatment to the wafers contained within the core tube. The cooling gas supply may include at least one cooling gas supply opening, the at least one cooling gas supply opening being arranged such that the cooling gas enters the cooling chamber in a flow direction substantially tangent to the circumferential wall.

[0007] There may also be provided a method for cooling a vertical batch furnace as claimed in claim 16. More specifically, there may be provided a method comprising providing a vertical batch furnace 10 as described and supplying cooling gas into the cooling chamber 20 with a flow direction substantially tangential to the circumferential wall. The substantially tangential flow direction may include an angle in the range of 90°±15° with respect to a longitudinal direction of the elongated circumferential wall 14 and an angle in the range of 0°±10° with respect to a plane passing through a point on the circumferential wall nearest said respective cooling gas supply opening and tangent to the circumferential wall.

[0008] For the purpose of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention are described hereinabove. Of course, it should be understood that not all such objects or advantages may be achieved by any particular embodiment of the invention. Thus, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes, for example, one advantage or group of advantages as taught or suggested herein, without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0009] Various embodiments are claimed in the dependent claims and will be further elucidated with reference to the examples shown in the figures. The embodiments may be combined or applied separately from each other.

[0010] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those of ordinary skill in the art from the following Detailed Description of Certain Embodiments, which refer to the accompanying drawings, and the invention is not limited to any particular embodiment disclosed.

[0011] While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the present disclosure, the advantages of the embodiments of the present disclosure may be more readily apparent from the following description of certain specific examples of embodiments of the present disclosure, when read in conjunction with the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] 1 shows an example of an illustrative vertical batch furnace assembly. [Diagram 2] 2 shows an upside down view of the top portion of the outer casing of the example of FIG. 1. [Diagram 3] 3 shows a schematic exploded perspective view of a detail of FIG. 2; [Figure 4] 1A and 1B show schematic cross-sectional views of an example of an end portion of a cooling gas inlet tube according to the description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In the present application, similar or corresponding features are indicated by similar or corresponding reference numerals. The description of the various embodiments is not limited to the examples shown in the figures, and the reference numerals used in the detailed description and claims are not intended to limit the description of the embodiments, but are included for a clear understanding of the embodiments.

[0014] Although certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments and / or applications of the present invention, as well as obvious modifications and equivalents thereof. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specific disclosed embodiments described below. The figures shown in this specification are not meant to be actual drawings of any particular materials, structures or devices, but are merely idealized representations used to describe embodiments of the present disclosure.

[0015] As used herein, the term "wafer" may refer to any underlying material or materials that may be used or upon which a device, circuit or film may be formed.

[0016] Most generally, the present disclosure may provide a vertical batch furnace assembly 10. The vertical batch furnace assembly 10 may include a core tube 12, an outer casing 16, a cooling chamber 20 bounded on a radially outer side by the outer casing 16 and on a radially inner side by the core tube 12, and at least one cooling gas supply radiating into the cooling chamber 20. The core tube 12 may have an elongated circumferential wall 14 extending in a longitudinal direction L, and the core tube 12 may be configured to house wafers for processing in the vertical batch furnace assembly 10. The outer casing 16 may extend around the core tube 12 and may include a heating element 18 for applying a heat treatment to the wafers contained within the core tube 12. The cooling gas supply may include at least one cooling gas supply opening 26, the at least one cooling gas supply opening 26 being arranged such that the cooling gas enters the cooling chamber 20 in a flow direction substantially tangent to the circumferential wall 14. A substantially tangential flow direction may include an angle in the range of 90 degrees ±15 degrees relative to the longitudinal axis L of the elongated circumferential wall 14. A substantially tangential flow direction may include an angle in the range of 0 degrees ±10 degrees relative to a plane passing through a point on the circumferential wall 14 that is closest to the respective cooling gas supply opening 26 and tangent to the circumferential wall 14.

[0017] With the gas flow direction from the gas supply openings 26 at least initially tangent to the circumferential wall 14, the cooling gas does not immediately flow along the longitudinal direction of the elongated circumferential wall 14, but instead spreads out tangentially to the circumferential wall 14. Only after the cooling gas spreads out tangentially to the circumferential wall 14 does the cooling gas flow along the longitudinal direction L of the elongated circumferential wall 14, as indicated by arrows F in FIG. 1. By initially distributing the cooling gas tangentially, the circumferential wall 14 is cooled more uniformly. In this way, cold spots are not formed and the disadvantages associated with these so-called cold spots are prevented.

[0018] In one embodiment, an example of which is shown in the exploded view of Figure 3, each cooling gas supply may comprise a cooling gas inlet tube 22, an end portion 24 of which extends into the cooling chamber 20. The end portion 24 may comprise at least one cooling gas supply opening 26, as also shown in Figure 4. Each cooling gas inlet tube 22 may be made in one piece. Each cooling gas inlet tube 22 may be made of a ceramic material. An axial end 28 of the cooling gas inlet tube 22 that extends into the cooling chamber 20 may be closed.

[0019] In the example shown in FIG. 4, the cooling gas inlet tube 22 extends into the cooling chamber 20. The cooling gas inlet tube 22 may extend through an opening 44 in the outer casing 16. The axial end 28 of the cooling gas inlet tube 22 may be closed to prevent the cooling gas from entering the cooling chamber 20 parallel to the longitudinal axis of the elongated circumferential wall 14. The end portion of the cooling gas inlet tube 22 shown includes two cooling gas supply openings 26. Each supply opening is oriented such that the cooling gas entering the cooling chamber 20 through said opening enters the cooling chamber 20 tangentially to the circumferential wall 14. The cooling gas inlet tube 22 may include a cam 46 arranged to cooperate with a corresponding recess 48 in the outer casing 16, the recess 48 being the portion of the opening 44 through which the cooling gas inlet tube 22 extends. The combination of the cam 46 on the cooling gas inlet tube 22 and the recess 48 in the outer casing 16 fixes the orientation of the cooling gas inlet tube 22 relative to the outer casing 16, and thus relative to the vertical batch furnace assembly 10 and core tube 12. This ensures that the cooling gas supply openings 26 have the correct orientation relative to the core tube 12, thereby ensuring that the cooling gas enters the cooling chamber 20 with a flow direction that is substantially tangent to the circumferential wall 14.

[0020] The cooling gas inlet tubes 22 may be heated during processing of the wafers in the core tube 12. The supplied cooling gas may cause a large drop in temperature of the cooling gas inlet tubes 22 as it starts to cool. This drop in temperature may cause internal stresses in the cooling gas inlet tubes 22. By embodying the cooling gas inlet tubes 22 as one integral piece, there are no weak joints in the cooling gas inlet tubes 22 that may cause the cooling gas inlet tubes 22 to break due to this internal stress. Preferably, each cooling gas inlet tube 22 is made of a ceramic material. Ceramic materials can withstand both high temperatures and large temperature fluctuations. This makes ceramic materials very suitable for the cooling gas inlet tubes 22.

[0021] 2, the at least one cooling gas supply 22 comprises a plurality of cooling gas supplies evenly spaced about the core tube 12. By evenly spaced apart the cooling gas supplies about the core tube 12, a uniform inflow of cooling gas along the elongated circumferential wall 14 can be obtained.

[0022] In one embodiment, an example of which is shown in Figure 1, the vertical batch furnace assembly 10 may further comprise at least one cooling gas exhaust 30 comprising at least one exhaust opening 31 for exhausting cooling gas from the cooling chamber 20. During operation, radiated cooling gas may flow along the elongated circumferential wall 14 of the core tube 12 from the at least one cooling gas supply to the at least one cooling gas exhaust 30.

[0023] The at least one cooling gas exhaust 30 may comprise a plurality of cooling gas exhausts 30 evenly spaced about the core tube 12. By evenly spaced apart the cooling gas exhausts 30 about the core tube 12, a uniform outflow of cooling gas along the elongated circumferential wall 14 may be obtained.

[0024] 1, at least one cooling gas supply may be located at or near a first longitudinal end 32 of the cooling chamber, and at least one cooling gas exhaust 30 may be located at or near a second longitudinal end 34 of the cooling chamber. In this manner, cooling gas flows longitudinally parallel along elongated circumferential wall 14, as indicated by arrows F.

[0025] The vertical batch furnace assembly 10 may further comprise a cooling gas recirculation channel 36 extending from the at least one cooling gas discharge 30 to the at least one cooling gas supply 22. The cooling gas recirculation channel 36 may comprise a pressure increase device 38, such as a fan or blower, and a heat exchanger 40 configured to cool the cooling gas within the recirculation channel 36. By recirculating the cooling gas, the cooling gas is reused, which means that there is no need to supply new cooling gas. This is particularly advantageous when the cooling gas is not ambient air, but is, for example, concentrated nitrogen, which must be purchased and may be in short supply. Furthermore, by not constantly introducing new cooling gas into the cooling chamber 20, neither debris nor contamination enters the cooling chamber 20. Also, harmful contamination originating from the cooling chamber or other parts of the vertical batch furnace assembly 10 is not released into the environment along with the cooling gas.

[0026] Preferably, the pressure augmentation device 38 may be located downstream of the heat exchanger 40. It may be desirable to have a particular level of pressure at the cooling gas supply opening 26. By having the pressure augmentation device 38 located downstream of the heat exchanger 40, the pressure augmentation device 38 requires less power to achieve a particular pressure at the cooling gas supply opening 26 as opposed to an arrangement in which the pressure augmentation device 38 is located upstream of the heat exchanger 40.

[0027] The configuration of the at least one cooling gas exhaust 30 may be similar to the configuration of the at least one cooling gas supply, with the flow direction of the cooling gas being reversible within the cooling chamber 20. The at least one cooling gas exhaust opening may be configured such that the cooling gas enters the cooling chamber 20 in a flow direction substantially tangent to the circumferential wall 14 when the flow direction of the cooling gas within the cooling chamber 20 is reversed and the cooling gas exhaust opening serves as the cooling gas supply opening 26.

[0028] The cooling gas may cool the core tube 12 by absorbing heat from said core tube 12. When flowing in one direction, the cooling gas is coldest when it enters the cooling chamber 20 and warmest when it exits through the cooling gas exhaust 30. This means that the portion of the circumferential wall 14 closest to the cooling gas exhaust 30 is cooled by the cooling gas to a lesser extent than the portion of the circumferential wall 14 closer to the cooling gas supply tube 22. To increase the overall cooling rate of the elongated circumferential wall 14, it may also be beneficial to have the cooling gas flow from the cooling gas exhaust 30 towards the cooling gas supply. The cooling gas may then flow along the circumferential wall 14 from the cooling gas supply to the cooling gas exhaust 30 for a certain period of time, thereby primarily cooling the portion of the circumferential wall 14 closest to the cooling gas supply. After the particular time, the flow direction may be reversed and the cooling gas may flow along the circumferential wall 14 from the cooling gas discharge 30 to the cooling gas supply 22 for the particular time, thereby primarily cooling the portion of the circumferential wall 14 closest to the cooling gas discharge 30. In this manner, the overall cooling efficiency of the cooling gas flow is increased.

[0029] In the example shown in FIG. 1, this flow reversal may be effected in that the inlet of the pressure intensifier 38 may be connected to two suction portions 36b of the recirculation channel 36. Each suction portion 36b may include an exhaust valve 52a, 52b. The outlet of the pressure intensifier 38 may be connected to the pressure portion 36a of the recirculation channel 36. The supply portion 36a of the cooling gas recirculation channel 36 is divided into two portions, each portion may include a diverter valve 42a, 42b. In use, only one of the suction portions 36b may be operable to transport cooling gas, the other one may be closed by the associated exhaust valve 52a or 52b. By skillfully switching between diverter valves 42a, 42b and exhaust valves 52a, 52b, the cooling gas can be directed either to at least one cooling gas supply 22 and then via the cooling chamber 20 to at least one cooling gas exhaust 30, or alternatively to at least one cooling gas exhaust 30 and then via the cooling chamber 20 to at least one cooling gas supply 22.

[0030] Apart from being functionally identical, the cooling gas exhaust 30 may also be structurally identical to the cooling gas supply 22. This is advantageous in constructing said cooling gas exhaust 30 and cooling gas supply 22, since only one type of part needs to be manufactured.

[0031] The present disclosure may also provide a method for cooling a vertical batch furnace. The method may include providing a vertical batch furnace 10 as described and supplying a cooling gas into the cooling chamber 20 in a flow direction substantially tangent to the circumferential wall 14.

[0032] In one embodiment, the substantially tangential flow direction comprises an angle in the range of 90 degrees ±15 degrees relative to the longitudinal axis L of the elongated circumferential wall 14 .

[0033] In one embodiment, the substantially tangential flow direction comprises an angle in the range of 0 degrees ±10 degrees relative to a plane passing through a point on the circumferential wall closest to each cooling gas supply opening 26 and tangent to the circumferential wall 14.

[0034] During the initial flow tangential to the circumferential wall 14, the cooling gas does not immediately flow along the longitudinal direction L of the elongated circumferential wall 14, but instead is distributed tangentially to the circumferential wall 14. Only after the cooling gas is distributed tangentially to the circumferential wall 14 does the cooling gas flow in the longitudinal direction L along the elongated circumferential wall 14. In this manner, there are no cold spots formed and the disadvantages associated with these so-called cold spots are avoided.

[0035] Although illustrative embodiments of the invention have been described above, in part with reference to the accompanying drawings, it should be understood that the invention is not limited to these embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0036] Throughout this specification, a reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Thus, the use of the phrases "in one embodiment" or "in an embodiment" in various places throughout this description do not necessarily refer to the same embodiment.

[0037] Furthermore, it should be noted that the specific features, structures, or characteristics of one or more of the various embodiments described above may be used and implemented independently of one another and may be combined in any suitable manner to form new embodiments not expressly described. The reference numbers used in the detailed description and claims do not limit the description of the embodiments and do not limit the claims. The reference numbers are used for clarity only. [Explanation of symbols]

[0038] 10-Vertical Batch Furnace Assembly 12-core tube 14-Circumferential wall 16-Outer casing 18-Heating element 20-Cooling Chamber 22-Cooling gas inlet tube 24-(Cooling gas inlet tube) end section 26-Cooling gas supply opening 28-Axial end (of cooling gas inlet tube) 30-Cooling gas exhaust section 32—First longitudinal end (of the cooling chamber) 34—Second longitudinal end (of the cooling chamber) 36-Cooling gas recirculation channel 38-Pressure Increasing Device 40-Heat exchanger 42a-Diverter valve 42b-Diverter valve 44 - Opening (in the outer casing) 46-Cam 48-Recess 52a-Exhaust valve 52b-Exhaust valve L-long axis direction

Claims

1. A vertical batch furnace assembly (10), comprising: a core tube (12) having an elongated circumferential wall (14) extending in a longitudinal direction, said core tube (12) configured to accommodate wafers for processing in said vertical batch furnace assembly (10); an outer casing (16) extending around said core tube (12) and equipped with heating elements (18) for applying a thermal treatment to the wafers contained within said core tube (12); a cooling chamber (20) bounded on its radially outer side by said outer casing (16) and on its radially inner side by said core tube (12); At least one cooling gas supply radiating into the cooling chamber (20); At least one cooling gas outlet (30), the cooling gas supply comprises at least one cooling gas supply opening (26), the at least one cooling gas supply opening (26) being configured such that cooling gas enters the cooling chamber (20) in a flow direction substantially tangential to the circumferential wall (14); 1. A vertical batch furnace assembly (10), wherein the cooling gas discharge section comprises at least one discharge opening, the at least one discharge opening being configured such that the cooling gas enters the cooling gas discharge section in a flow direction substantially tangent to the circumferential wall (14).

2. 2. The vertical batch furnace assembly of claim 1, wherein said substantially tangential flow direction comprises an angle in the range of 90 degrees plus or minus 15 degrees relative to said longitudinal axis of said elongated circumferential wall (14).

3. 3. The vertical batch furnace assembly of claim 1, wherein the substantially tangential flow direction comprises an angle in the range of 0 degrees ±10 degrees relative to a plane passing through a point on the circumferential wall closest to each cooling gas supply opening (26) and tangent to the circumferential wall.

4. 4. The vertical batch furnace assembly of claim 1, wherein each cooling gas supply comprises a cooling gas inlet tube (22), an end portion (24) of said cooling gas inlet tube (22) extending into said cooling chamber (20), said end portion (24) comprising said at least one cooling gas supply opening (26).

5. 5. The vertical batch furnace assembly of claim 4, wherein each cooling gas inlet tube (22) is embodied as one integral piece.

6. 6. The vertical batch furnace assembly of claim 4 or 5, wherein each cooling gas inlet tube (22) is made of a ceramic material.

7. The vertical batch furnace assembly of any one of claims 4 to 6, wherein an axial end (28) of the cooling gas inlet tube (22) that extends into the cooling chamber (20) is closed.

8. The vertical batch furnace assembly of any one of claims 1 to 7, wherein said at least one cooling gas supply comprises a plurality of cooling gas supplies evenly spaced around said core tube (12).

9. A vertical batch furnace assembly as described in any one of claims 1 to 8, wherein during operation, the radiated cooling gas flows along the elongated circumferential wall (14) of the core tube (12) from at least one cooling gas supply section to at least one cooling gas discharge section (30).

10. 10. The vertical batch furnace assembly of claim 9, wherein said at least one cooling gas discharge (30) comprises a plurality of cooling gas discharges (30) evenly spaced about said core tube (12).

11. 11. The vertical batch furnace assembly of claim 9, wherein the at least one cooling gas supply is located at or near a first longitudinal end (32) of the cooling chamber and the at least one cooling gas exhaust (30) is located at or near a second longitudinal end (34) of the cooling chamber.

12. The cooling gas supply system further comprises a cooling gas recirculation channel (36, 36a, 36b) extending from the at least one cooling gas exhaust (30) to the at least one cooling gas supply, the cooling gas recirculation channel (36a, 36b) comprising: - a pressure increasing device (38) such as a fan or blower; A vertical batch furnace assembly according to any one of claims 9 to 11, comprising a heat exchanger (40) configured to cool the cooling gas in the recirculation channels (36a, 36b).

13. 13. The vertical batch furnace assembly of claim 12, wherein the pressure increase device (38) is located downstream of the heat exchanger (40).

14. 14. The vertical batch furnace assembly according to claim 9, wherein a configuration of the at least one cooling gas discharge (30) is similar to a configuration of the at least one cooling gas supply (26), the flow direction of the cooling gas in the cooling chamber (20) is reversible, and the at least one discharge opening is configured such that the cooling gas enters the cooling chamber (20) in a flow direction substantially tangential to the circumferential wall (14) when the flow direction of the cooling gas in the cooling chamber (20) is reversed and the discharge opening serves as a cooling gas supply opening (26).

15. 15. The vertical batch furnace assembly according to claim 14 when dependent on at least claim 12, wherein the cooling gas recirculation channel (36) comprises a diverter valve (42a, 42b) and / or an exhaust valve (52a, 52b) for directing the cooling gas either to the at least one cooling gas supply and then via the cooling chamber (20) to the at least one cooling gas exhaust (30), or alternatively to the at least one cooling gas exhaust (30) and then via the cooling chamber (20) to the at least one cooling gas supply.

16. 1. A method for cooling a vertical batch furnace, comprising: - providing a vertical batch furnace assembly (10) according to any one of claims 1 to 15, - supplying cooling gas into said cooling chamber (20) in a flow direction substantially tangential to said circumferential wall.

17. 17. The method of claim 16, wherein the substantially tangential flow direction comprises an angle in the range of 90 degrees + / - 15 degrees relative to the longitudinal axis of the elongated circumferential wall (14).

18. 18. The method of claim 16 or 17, wherein the substantially tangential flow direction comprises an angle in the range of 0 degrees ±10 degrees relative to a plane passing through a point on the circumferential wall that is closest to the respective cooling gas supply opening (26) and tangent to the circumferential wall (14).

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