High-brightness lamp support for rapid heat treatment furnace

Abstract

The present disclosure relates to a support (60) for a high-intensity lamp (24). The support (60) is made of a first material and includes a surface (70) for facing the high-intensity lamp, a first member (62) for supporting the high-intensity lamp, a second member (64) made of a second material different from the first material, covering the first member and attached to the first member, and a sheet (90) made of a third material different from the first material, intervening between the first member and the second member and defining, together with the second member, at least one cavity (72) for accommodating a coolant.

Description

Technical Field

[0001] The present disclosure generally relates to a high-intensity lamp support for a rapid thermal processing furnace and a rapid thermal processing furnace comprising such a support.

Background Art

[0002] A rapid thermal processing furnace is a furnace that enables an object (especially a silicon substrate) to be heated to a high temperature of, for example, 1200 °C or higher in a very short time (usually several seconds).

[0003] Such a temperature rise is obtained by high-intensity lamp or laser heating. In the case of a high-intensity lamp, especially an infrared lamp, the furnace includes a lamp support. The support has a wall facing the lamp adapted to reflect the radiation emitted from the lamp towards the object to be heated. Generally, it is also necessary to provide a cooling system for the support, for example, a water circulation system in the internal pipes of the support.

[0004] It is known to manufacture a high-intensity lamp support for a rapid thermal processing furnace comprising aluminum parts assembled by screwing and cooled by water. The drawback is that aluminum can be corroded by water circulation, which requires maintenance work to replace the parts of the support.

[0005] One object of an embodiment is to provide a high-intensity lamp support for a rapid thermal processing furnace that overcomes all or some of the drawbacks of existing high-intensity lamp supports.

[0006] Another object of an embodiment is to simplify the manufacturing method of the high-intensity lamp support.

[0007] Another object of an embodiment is to reduce the manufacturing cost of the high-intensity lamp support.

[0008] Another object of an embodiment is to reduce the maintenance cost of the high-intensity lamp support.

[0009] Another object of the embodiment is to provide a wall adapted such that the support reflects the radiation emitted by the lamp.

[0010] Another object of the embodiment is to integrate pipes for circulating a coolant in the support.

[0011] One embodiment provides a support for a high-intensity lamp. The support comprises a first member made of a first material, having a surface for facing the high-intensity lamp, and supporting the high-intensity lamp, a second member made of a second material different from the first material, covering the first member and attached to the first member, a sheet made of a third material different from the first material, interposed between the first member and the second member, and defining at least one cavity designed to accommodate a coolant together with the second member and.

[0012] According to one embodiment, the second material and the third material are stainless steel.

[0013] According to one embodiment, the second material and the third material have a lower thermal conductivity than the first material.

[0014] According to one embodiment, the first material is included in the group consisting of aluminum, aluminum alloys having good suitability for mechanical mirror polishing, copper, and copper alloys such as brass.

[0015] According to one embodiment, the second material is included in the group consisting of stainless steel, plastics resistant to temperatures exceeding 100°C, and composite materials resistant to temperatures exceeding 100°C.

[0016] According to one embodiment, the third material is included in the group consisting of stainless steel, copper, and copper alloys such as brass.

[0017] According to one embodiment, the thickness of the sheet ranges from 0.03 mm to 0.3 mm.

[0018] One embodiment also provides a rapid thermal processing furnace comprising a high-intensity lamp and a support for the high-intensity lamp as defined above.

[0019] According to one embodiment, the high-intensity lamp is an infrared lamp.

[0020] According to one embodiment, the furnace comprises a system for circulating a coolant in the cavity.

[0021] According to one embodiment, the coolant includes water.

Brief Description of the Drawings

[0022] These features and advantages, as well as other features and advantages, are described in detail in the following description of specific embodiments given in connection with the accompanying drawings in a non-limiting manner.

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0024] Like features are indicated by like reference numerals in different drawings. In particular, structural and / or functional features common to different embodiments may have the same reference numbers and may exhibit the same structural, dimensional, and material characteristics. For clarity, only steps and elements useful for understanding the embodiments described herein are shown and described in detail.

[0025] Unless otherwise specified, the terms "about", "substantially", and "degree" mean within 10%, preferably within 5%. Unless otherwise specified, ordinal adjectives such as "first", "second", etc. are used only to distinguish elements from each other. In particular, these adjectives do not limit the described embodiments to a particular order of these elements.

[0026] FIG. 1 is a partial schematic cross-sectional view of an example of a rapid thermal processing furnace 10.

[0027] The furnace 10 includes an enclosure 12, also referred to as a reactor, in which a workpiece 14 placed on a mounting table 16 is disposed. The workpiece 14 is, for example, a silicon substrate. An inert gas can be injected into the internal volume 18 of the reactor 12 by an injection system 20. The internal volume 18 of the reactor 12 can be maintained at a low pressure by a pump system 22. The workpiece 14 is heated by radiation emitted by a high-intensity lamp 24 held by a support 30. The high-intensity lamp 24 is, for example, an infrared lamp.

[0028] The quartz port hole 26 allows the IR radiation emitted by the lamp 24 to pass through and ensures the sealing of the internal volume 18 of the reactor 12. The support 30 is further adapted to reflect the IR radiation emitted by the lamp 24 back to the port hole 26. The walls of the reactor 12 are cooled to avoid contamination of the substrate 14 in particular and to protect the control and / or measuring devices attached to the reactor 12. The temperature of the substrate 14 can be controlled by a regulator coupled to a pyrometer 28.

[0029] FIG. 2 is a partial schematic cross-sectional view of an example of the support 30 of the lamp 24, and a single lamp 24 is shown in FIG. 2. The cross-section of FIG. 2 is orthogonal to the cross-section of FIG. 1. The support 30 is formed of a first member 32 and a second member 34 that are attached to each other by screws 36. Preferably, there is no weld between the first member 32 and the second member 34.

[0030] The lamp 24 is attached to the first member 32. The first member 32 includes, for example, for each lamp 24, two openings 38 in which the ends of the lamp 24 are received. The first member 32 includes a wall 40 facing the lamp 24. The wall 40 forms a mirror that reflects the radiation emitted by the lamp 24.

[0031] When the members 32 and 34 are assembled, the members 32 and 34 define an internal cavity 42 through which a coolant, such as water, circulates. The internal cavity 42 can be defined by a recess 44 provided in the first member 32 when the second member 34 is assembled to the first member 32, and the recess 44 is closed by a flat surface 46 of the second member 34.

[0032] The first member 32 may include a groove 48 on the side of the second member 34. Sealing of the internal cavity 42 can be achieved by an O-ring 50 disposed in the groove 48.

[0033] When the lamp 24 is an infrared lamp, the members 32 and 34 may be made of aluminum. Aluminum is a low-cost material, a good conductor of heat, and a good reflector of infrared radiation emitted by the lamp 24.

[0034] A drawback is that when the coolant circulating in the cavity 42 contains water, the members 32 and 34 may corrode when they come into contact with the coolant. It is conceivable to apply an anticorrosion treatment to the walls of the cavity 42. However, this tends to complicate the manufacturing method of the support 30 and increase the manufacturing cost.

[0035] FIG. 3 is a partial schematic cross-sectional view of an embodiment of a support 60 for a lamp 24 that can be used as the support 30 for the furnace 1 shown in FIG. 1. FIG. 4 is an exploded cross-sectional view of the support 60 of FIG. 3. The cross-sections of FIGS. 3 and 4 are orthogonal to the cross-section of FIG. 1. A single lamp 24 is shown in FIGS. 3 and 4.

[0036] The support 60 comprises a stack of a first member 62, a sheet 90, and a second member 64 that are attached to each other by screws 66, and three screws are shown as an example in FIGS. 3 and 4. The sheet 90 is sandwiched between the first member 62 and the second member 64. Preferably, there is no welded portion between the first member 62, the second member 64, and the sheet 90.

[0037] The first member 62 comprises a portion 63 that has a central axis D, has a substantially square or rectangular cross-section, and is extended by a peripheral portion 65 that extends to the side opposite the second member 64. The lamp 24 is fixed to the edge portion 65 of the first member 62. The edge portion 65 of the first member 62 comprises, for example, for each lamp 24, two openings 68 in which the end portion of the lamp 24 is received. The first member 62 comprises a wall 70 that faces the lamp 24 and forms a mirror that reflects the radiation emitted by the lamp 24. According to one embodiment, the wall 70 comprises a square or rectangular flat region in the central portion 63 of the first member 62 and a square or rectangular region in the edge portion 65. The first member 62 comprises a surface 71 that is located on the sheet 90 side. The sheet 90 is applied to the surface 71 when the first member 62, the sheet 90, and the second member 64 are attached to each other by screws 66. According to one embodiment, the surface 71 is flat and the sheet 90 is flat. According to one embodiment, the shape of the surface 71 is square or rectangular.

[0038] When the members 62, 64, and the sheet 90 are assembled, they define an internal cavity 72 in which a coolant (for example, water that may contain additives) circulates during operation. The internal cavity 72 is defined by a recess 74 provided in the second member 64 that is closed by the sheet 90 when the second member 64 is assembled to the first member 62 with the sheet 90 interposed therebetween. The second member 64 comprises a groove 78 on the first member 62 side. Sealing of the internal cavity 72 can be achieved by an O-ring 80 disposed in the groove 78.

[0039] The first member 62 is made of a first material. According to one embodiment, the first material is included in the group consisting of aluminum, aluminum alloys having good suitability for mechanical mirror polishing, copper, and copper alloys such as brass. The surface 70 that forms a mirror with respect to the radiation of the lamp 24 can be obtained in a simple manner by mechanical polishing without the need to deposit a reflective coating on the surface 70. According to one embodiment, the roughness Ra of the surface 70 is less than 0.2. According to one embodiment, the surface 70 reflects more than 90% of the radiation emitted by the lamp 24. According to one embodiment, the radiation emitted by the lamp 24 has a wavelength in the range of 0.5 μm to 4 μm, and preferably has an emission peak at 1 μm when the filament temperature is 2500K.

[0040] The average thickness of the first member 62 in the portion facing the cavity 72 is in the range of 4 mm to 8 mm. According to one embodiment, the thickness of the peripheral portion 65 of the first member 62 measured along the axis D is in the range of 10 mm to 20 mm. Since the first material is a good conductor of heat, there is no need to directly provide a cavity for circulating a coolant within the edge 65 of the first member 62, and the heat transferred to the first member 62 by the lamp 24 can be efficiently discharged to the coolant.

[0041] The second member 64 is made of a second material different from the first material. The second material is stainless steel. The second material may have a lower thermal conductivity than the first material. According to one embodiment, the second material is included in the group consisting of stainless steel, plastics resistant to temperatures above 100°C, particularly thermoplastic plastics based on polyoxymethylene, and composite materials resistant to temperatures above 100°C. The depth of each recess 74 measured along the axis D may be in the range of 5 mm to 10 mm.

[0042] Unlike the first material, the sheet 90 is made of a third material which may in some cases be the same as the second material. The third material is stainless steel. The third material may have a lower thermal conductivity than the first material, but is preferably a metal to ensure sufficient heat conduction. According to one embodiment, the third material is included in the group consisting of stainless steel, copper, and copper alloys such as brass. According to one embodiment, the thickness of the sheet 90 is less than 0.5 mm, preferably in the range of 0.03 mm to 0.3 mm. Since the sheet 90 is thin, it is easy to deform.

[0043] According to one embodiment, the sheet 90 completely covers the surface 71 of the first member 62. When the surface 71 corresponds to a square or a rectangle, the sheet 90 corresponds to a square or a rectangle with the same surface area.

[0044] During operation, the coolant contacts only the stainless steel material. This has the advantage of preventing corrosion of the support 60, especially when the coolant is water-based. Furthermore, there is no need to apply an anti-corrosion treatment to the walls of the cavity 72. Therefore, the manufacturing method of the support 60 remains simple.

[0045] During operation, the coolant present in the cavity 72 is under pressure and holds the sheet 90 as if it were pressed against the first member 62. In this way, direct contact between the sheet 90 and the first member 62 is obtained substantially without the intervention of an air film. Therefore, good heat transfer is obtained between the first member 62 and the sheet 90. According to one embodiment, the pressure of the coolant in the cavity 72 is in the range of 0.1 MPa to 0.5 MPa, preferably 0.3 MPa to 0.4 MPa. Furthermore, considering the thin thickness of the sheet 90, even if the sheet 90 is made of a third material (preferably a metal) having a lower thermal conductivity than the first material forming the first member 62, the heat conduction between the first member 62 and the coolant through the very thin sheet 90 is sufficiently effective to enable proper cooling of the first member 62 during operation.

[0046] Various embodiments and variations have been described. Those skilled in the art will understand that they can combine specific features of these various embodiments and variations, and other variations will also be apparent to those skilled in the art.

[0047] Finally, the actual implementation of the described embodiments and variations is within the scope of those skilled in the art based on the functional instructions given above.

[0048] This patent application claims the priority of French Patent Application No. 22 / 05604, which is considered a part of this specification.

Claims

1. A support (60) for a high-intensity lamp (24), made of a first material and having a surface (70) for facing the high-intensity lamp, and a first member (62) for supporting the high-intensity lamp; a second member (64) made of a second material different from the first material, covering the first member and attached to the first member; a sheet (90) made of a third material different from the first material, interposed between the first member and the second member, and defining at least one cavity (72) for accommodating a coolant together with the second member and comprising a support for a high-intensity lamp.

2. The support according to claim 1, wherein the second material and the third material are stainless steel.

3. The support according to claim 1 or 2, wherein the second material and the third material have a lower thermal conductivity than the first material.

4. The support according to any one of claims 1 to 3, wherein the first material is included in the group consisting of aluminum, aluminum alloys having good suitability for mechanical mirror polishing, copper, and copper alloys such as brass.

5. The support according to any one of claims 1 to 4, wherein the second material is included in the group consisting of stainless steel, plastics resistant to temperatures exceeding 100°C, and composite materials resistant to temperatures exceeding 100°C.

6. The support according to any one of claims 1 to 5, wherein the third material is included in the group consisting of stainless steel, copper, and copper alloys such as brass.

7. The support according to any one of claims 1 to 6, wherein the thickness of the sheet (90) is in the range of 0.03 mm to 0.3 mm.

8. A rapid thermal processing furnace comprising a high-intensity lamp (24) and a support (60) for a high-intensity lamp according to any one of claims 1 to 7.

9. The rapid thermal processing furnace according to claim 8, wherein the high-intensity lamp (24) is an infrared lamp.

10. The rapid thermal processing furnace according to claim 8 or 9, comprising a system for circulating the coolant in the cavity.

11. The rapid thermal processing furnace according to claim 8, wherein the coolant contains water.

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