Wafer boat

Abstract

A wafer boat configured to be placed on a pedestal of a vertical batch furnace, the pedestal having a substantially planar support surface. The wafer boat includes a support ring defining a substantially planar bottom end surface of the wafer boat, and an alignment ring substantially concentric with the support ring. The support surface of the pedestal or the bottom side of the alignment ring is provided with a plurality of alignment elements that respectively protrude upward from the support surface or downward from the alignment ring, and the other is provided with a plurality of alignment openings configured to accommodate the plurality of alignment elements therein. The support ring protrudes downward beyond the alignment ring such that when the wafer boat is placed on the pedestal, the support ring is supported on the support surface while the alignment ring is spaced apart from the support surface of the pedestal.

Description

Technical Field

[0001] This disclosure generally relates to a wafer boat configured to support multiple wafers and placed on the base of a vertical batching furnace. Background Technology

[0002] Most vertical batch furnaces are equipped with a base for supporting wafer boats and for transferring the wafer boats to the processing chamber. Typically, the wafer boat rests on a small cylindrical base on the base. The base allows the wafer boat to be moved vertically to a processing position within the processing chamber. Summary of the Invention

[0003] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the following description of exemplary embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0004] It can be recognized that in order to achieve uniform processing of wafers in a wafer boat, such as uniformly depositing material on the wafer surface within the wafer boat, it may be necessary to position the wafer boat vertically and concentrically relative to the processing chamber. When the wafer boat is placed on the base of a vertical batch furnace, the bottom or contact surface may therefore need to have a high level of flatness. A high level of flatness will prevent the wafer boat from tilting and make straight alignment between the wafer boat and the processing chamber possible. Insufficient flatness will cause the wafer boat to tilt relative to the processing chamber, which, for example, can lead to uneven deposition during the process.

[0005] It may also be desirable to have a small contact surface between the wafer boat and the substrate. A small contact surface can minimize heat conduction from the wafer boat to the substrate, thereby minimizing heat loss.

[0006] Therefore, the object of the present invention is to provide a wafer boat that can be provided with an alignment system relative to a substrate, the alignment system being able to achieve sufficient flatness to allow the substrate to rotate with the wafer boat placed on the substrate, and to minimize heat loss.

[0007] For this purpose, a wafer boat can be provided. More specifically, a wafer boat configured to support multiple wafers and be placed on a base of a vertical batching furnace can be provided. The base can have a substantially flat support surface. The wafer boat can define a central wafer boat axis that extends substantially vertically when the wafer boat is placed on the base. The wafer boat can include a support ring and an alignment ring. The support ring can define a substantially flat bottom surface of the wafer boat. The alignment ring can be substantially concentric with the support ring. A plurality of alignment elements can be provided on the support surface of the base or the bottom side of the alignment ring, the alignment elements protruding upward from the support surface or downward from the alignment ring, respectively. Another of the support surface and the alignment ring is provided with a plurality of alignment openings configured to receive a plurality of alignment elements therein. The support ring can protrude downward beyond the alignment ring in the direction of the central wafer boat axis, such that when the wafer boat is placed on the base, the support ring can be supported on the support surface, while the alignment ring can be spaced apart from the support surface of the base.

[0008] Components for aligning and rotating the wafer boat may also be provided. These components may include the wafer boat and base as described. The base may include a substantially flat support surface and a plurality of alignment elements projecting upward from the support surface, configured to be received in a plurality of alignment openings in an alignment ring, or a plurality of alignment openings configured to receive a plurality of alignment elements on the alignment ring therein.

[0009] A vertical batching furnace assembly for processing wafers may also be provided. This vertical batching furnace assembly may include a processing chamber, a wafer processing space, and a wafer boat processing apparatus. The processing chamber can be configured to apply thermal or chemical treatment to batches of wafers. The wafer processing space may be equipped with the components described. The wafer boat processing apparatus can be configured to transfer components between the wafer processing space and the processing chamber.

[0010] In order to summarize the present invention and the advantages obtained relative to the prior art, certain objects and advantages of the present invention have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the present invention. Therefore, for example, those skilled in the art will recognize that the present invention may be implemented or performed in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0011] Various embodiments are claimed in the dependent claims, and these embodiments will be further illustrated with reference to the examples shown in the accompanying drawings. The embodiments may be combined or applied separately from each other.

[0012] All of these embodiments are within the scope of the invention disclosed herein. These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments, with reference to the accompanying drawings. The invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0013] When read in conjunction with the accompanying drawings, the advantages of the embodiments of this disclosure can be more readily determined from the description of certain examples, wherein:

[0014] Figure 1 A cross-sectional perspective view of an example of a wafer boat according to the description is shown;

[0015] Figure 2 It shows Figure 1 Bottom details;

[0016] Figure 3 The perspective sectional view shows, for example Figure 2 The bottom detail of the example wafer boat shown, with the wafer boat placed on a base also shown in cross-section; and

[0017] Figure 4 A bottom view of an example of a wafer boat as described is shown. Detailed Implementation

[0018] In this application, similar or corresponding features are indicated by similar or corresponding reference numerals. The description of 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 to illustrate the embodiments.

[0019] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specific disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, the scope of the disclosed invention should not be limited to the specific disclosed embodiments described below. The illustrations presented herein are not intended to be actual views of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of this disclosure.

[0020] As used herein, the term “wafer” can refer to any one or more underlying materials on which devices, circuits or films can be formed or on which they can be used.

[0021] In the most common terms, this disclosure provides a wafer boat 10. The wafer boat can be configured to support a plurality of wafers and can be configured to be placed on a base 12 of a vertical batch furnace. The base 12 can have a substantially flat support surface 14. The wafer boat 10 can define a central wafer boat axis 16, which can extend substantially vertically when the wafer boat 10 is placed on the base 12. The wafer boat 10 can include a support ring 18 and can include an alignment ring 22. The support ring 18 can define a substantially flat bottom end surface 20 of the wafer boat 10. The alignment ring 22 can be substantially concentric with the support ring 18. A plurality of alignment elements 24 can be provided on the support surface 14 of the base 12 or on the underside of the alignment ring 22, the alignment elements 24 projecting upward from the support surface 14 or downward from the alignment ring 22, respectively. The other of the support surface 14 and the alignment ring 22 can be provided with a plurality of alignment openings 26 configured to receive the plurality of alignment elements 24 therein. The support ring 18 can protrude downward beyond the alignment ring 22 in the direction of the central wafer boat axis 16, so that when the wafer boat 10 is placed on the base 12, the support ring 18 can be supported on the support surface 14, while the alignment ring 22 can be spaced apart from the support surface 14 of the base 12.

[0022] Using the support ring 18 and alignment ring 22, the base 12 can apply different forces to the wafer boat 10 during placement on the base 12 and once placed on the base 12. The base 12 can apply a vertical force to support and lift the wafer boat 10. The base 12 can also apply a lateral horizontal force to rotate the wafer boat 10. The base 12 can also apply a force on a horizontal plane to translate the wafer boat 10 on said horizontal plane. The base 12 can also apply a horizontal force to move the wafer boat 10 relative to the base 12 to align the wafer boat 10 in the correct position on the base 12.

[0023] The protruding alignment element 24 and alignment opening 26 form an alignment system that allows the wafer boat 10 to be positioned and rotated at the correct angle relative to the base 12 and therefore also relative to the processing chamber. Precise placement can be achieved by carefully selecting the placement of the alignment element 24 and the matching alignment opening 26. When the wafer boat 10 is placed on the base 12, the alignment element 24 slides into the alignment opening 26, thereby aligning the wafer boat 10 with the base 12.

[0024] When placed on the base 12, the support ring 18 is configured to receive vertical support forces. Simultaneously, the alignment opening 26 or alignment element 24 in or on the alignment ring 22 will be able to receive horizontal forces from the base 12. The mating alignment element 24 and alignment opening 26 can transfer rotational motion to the wafer boat 10. The alignment element 24 can be implemented, for example, as a protrusion or rod, and the opening can be implemented as a mating hole. Of course, the engagement between the alignment element 24 and the alignment opening 26 can also be used to induce translation on the wafer boat 10, or a combination of translation and rotation.

[0025] The wafer boat 10 can rest its bottom surface 20 of support ring 18 on the support surface 14 of base 12. There can be a single contact surface between the wafer boat 10 and base 12. In contrast, the feet of a known wafer boat can each have a contact surface independent of the contact surface of another foot. Due to these independent contact surfaces, achieving sufficient flatness can be difficult. Because there can be a single contact surface, it may be easier to manufacture said surface and obtain the sufficient flatness required for aligning the wafer boat 10 compared to multiple contact surfaces with corresponding feet.

[0026] Conductive heat loss may only travel through the bottom surface 20 to the support ring 18. By using the support ring 18, the radial width of the ring 18 can be selected to minimize this conductive heat loss.

[0027] In one embodiment, the support ring 18 may be annular and may have an inner diameter 28 and an outer diameter 30. The difference between the inner diameter 28 and the outer diameter 30 may be less than 10 mm, preferably between 4 and 5 mm.

[0028] Due to its smaller radial width, the relatively thin support ring 18 can have a relatively small bottom surface 20. The radial width may need to be sufficient to provide support for the wafer boat, while the small bottom surface can minimize heat conduction losses from the wafer boat 10 to the base 12.

[0029] In one embodiment, the support ring 18 and the alignment ring 22 may be integrally formed.

[0030] Using this one-piece implementation, the support ring 18 and alignment ring 22 can be fixed relative to each other, meaning that relative alignment is no longer necessary when constructing the wafer boat 10. Furthermore, friction and wear between parts during use are avoided. This means that tiny particles or debris that could contaminate the wafer in the wafer boat will not be generated.

[0031] In one embodiment, the alignment element 24 may be disposed on the support surface 14. A plurality of alignment openings 26 may be disposed in the alignment ring 22 and may extend through the support ring 18. Alternatively, the alignment element 24 may be disposed on the underside of the alignment ring 22, and the plurality of alignment openings 26 may be disposed in the support surface 14 of the base 12. It is also possible that one or more of the plurality of alignment elements 24 are disposed on the support surface 14, while another portion of the plurality of alignment elements 24 is disposed on the underside of the alignment ring 22.

[0032] In one embodiment, an example of which is shown in the accompanying drawings, the alignment element 24 may be disposed on the support surface 14. A plurality of alignment openings 26 may be implemented as slots 26 passing through the alignment ring 22 and optionally the support ring 18. Each slot 26 may be a substantially straight slot 26 having a slot axis 32. Each slot axis 32 may extend through the center point of the alignment ring 22 and optionally the support ring 18 and may extend radially outward. The plurality of slots 26 may include three slots 26 that may be circumferentially spaced at intermediate angles of substantially 105° to 135° along the circumference of the alignment ring. The intermediate angles may be, for example, substantially 110°, substantially 120°, and substantially 130°.

[0033] The slot 26 and alignment element 24 can be arranged such that the placement of the wafer boat 10 onto the base 12 can be unique. Because the slot 26 can have an elongated shape, the protruding alignment element 24 can move within the length of the slot 26, but not within its width. By carefully selecting the placement of the slot 26, the position of the wafer boat 10 relative to the base 12 can be precisely determined, while the fixation is not overly constrained. Figure 4 As illustrated in the example, by extending the slot axis 32 through the center point, the wafer boat 10 can be aligned relative to that center point. Three slots 26 may be sufficient to precisely align the wafer boat 10 relative to the base 12 and prevent relative movement with each other. By spreading these three angles almost, but not entirely, uniformly, it is possible for the wafer boat 10 to have only one rotational position relative to the base 12.

[0034] In an alternative embodiment, the alignment element 24 may be disposed on the alignment ring 22, and the plurality of alignment openings 26 may be implemented as slots in the support surface 14.

[0035] This configuration of the alignment element 24 and the alignment opening 26 can have the same effects and advantages as the embodiment in which the alignment element 24 is disposed on the base 12 and the slot 26 is disposed in the alignment ring 22.

[0036] In one embodiment, the width of each slot 26 is such that each alignment element 24 is tightly fitted in its respective slot 26, making radial movement of the alignment element in the relevant slot 26 possible and preventing movement of the alignment element in the tangential direction of the alignment ring 22.

[0037] By arranging the multiple slots 26, particularly the three slots 26, at an angle to each other, the position of the wafer boat 10 relative to the base 12 is defined without being overly constrained. These effects also apply to embodiments where the protruding alignment element 24 is disposed on the support surface 14 and the alignment opening 26 is disposed in the alignment ring 22, as well as embodiments where the protruding alignment element 24 is disposed on the alignment ring 22 and the alignment opening 26 is disposed in the support surface 14.

[0038] In one embodiment, an example is in Figure 1 As shown, the wafer boat 10 may further include at least two pillars 34, preferably three pillars 34, which are connected to and extend upward from the alignment ring 22 parallel to the central wafer boat axis 16. Each pillar 34 may include a plurality of slits 34 for supporting multiple wafers. The wafer boat may also include a top plate 36 connected to the upper ends of at least two pillars 32. The wafer boat 10 may also include a bottom plate 38 extending inward from the alignment ring 22 and may be concentric with the alignment ring 22. The support ring 18, the alignment ring 22, and the bottom plate 38 may be integrally formed.

[0039] Like the integrally formed support ring 18 and alignment ring 22, the integrally formed support ring 18, alignment ring 22, and base plate 38 can be fixed relative to each other, meaning that relative alignment is no longer necessary when constructing the wafer boat 10. Furthermore, friction and wear between parts during use are avoided. This means that particles or debris that could contaminate the wafer in the wafer boat will not be generated.

[0040] The support column 34 can extend vertically. The top plate 36 can stabilize the upwardly extending support column 34. Multiple slits 34 can be evenly spaced so that the supported wafers are equidistant from each other. This can further promote a uniform deposition process.

[0041] In one embodiment, an example of which is shown in the figure, the support ring 18 may be configured radially outside the alignment ring 22.

[0042] In this embodiment, the support ring 18, which is typically used as the base of the wafer boat, can have a larger diameter than the alignment ring 22. A larger diameter means that the support ring 18 can provide greater stability to the wafer boat 10.

[0043] In one embodiment, the support ring 18 and the alignment ring 22 may be made of quartz.

[0044] The wafer boat 10 and alignment system may need to withstand high temperature differences that could lead to high stress in the wafer boat material. Quartz may be well-suited to meet this requirement. Other parts of the wafer boat 10, besides the alignment ring 22 and support ring 18, can also be made of quartz. Examples include possible pillars 32, top plates 36, and / or bottom plates 38.

[0045] This disclosure may also provide components 10, 12 for aligning and rotating the wafer boat 10. Components 10, 12 may include the wafer boat 10 and base 12 as described. The base 12 may include a substantially flat support surface 14 and may include a plurality of alignment elements 24 projecting upward from said support surface 14, configured to be received in a plurality of alignment openings 26 in an alignment ring 22, or a plurality of alignment openings 26 configured to receive therein the plurality of alignment elements 24 on the alignment ring 22.

[0046] The effects and advantages of components 10 and 12 are similar to those described above regarding the advantages of wafer boat 10, and these effects and advantages are inserted here by reference.

[0047] In one embodiment, the alignment element 24 may be a pin extending upward from the base support surface 14.

[0048] Therefore, the component can provide pins and openings, or a combination of pins and slots, with which the wafer boat 10 and base 12 can be aligned.

[0049] This disclosure may further provide a vertical batching furnace assembly for processing wafers. The vertical batching furnace assembly may include a processing chamber, a wafer processing space, and a wafer boat processing apparatus. The processing chamber may be configured to apply thermal or chemical treatment to batches of wafers. As described, the wafer processing space may be provided with components 10 and 12. The wafer boat processing apparatus may be configured to transfer components 10 and 12 between the wafer processing space and the processing chamber.

[0050] The effects and advantages of the vertical batch furnace assembly are similar to those described above with respect to assemblies 10, 12 and wafer boat 10, and these effects and advantages are inserted by reference.

[0051] 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. By studying the drawings, the disclosure, and the appended claims, those skilled in the art will understand and implement variations of the disclosed embodiments in practicing the claimed invention.

[0052] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the appearance of the phrase "in an embodiment" or "in an embodiment" throughout this specification does not necessarily refer to the same embodiment.

[0053] Furthermore, it should be noted that one or more specific features, structures, or characteristics in the various embodiments described above can be used and implemented independently of each other, and can be combined in any suitable manner to form new, undescribed embodiments. The reference numerals used in the detailed description and claims do not limit the description of the embodiments, nor do they limit the claims. The reference numerals are for clarification only.

[0054] List of reference numerals

[0055] 10 – Chip Boat

[0056] 12 – Base

[0057] 14 – Support Surface

[0058] 16 – Central wafer boat axis

[0059] 18 – Support Ring

[0060] 20 – Bottom surface

[0061] 22 – Alignment Ring

[0062] 24 – Pin

[0063] 26 – Slot

[0064] 28 – (Inner diameter of the support ring)

[0065] 30 – (outer diameter of the support ring)

[0066] 32 – Slot axis

[0067] 32 – Pillars

[0068] 34 – Slit

[0069] 36 – Top Plate

[0070] 38 – Base Plate

Claims

1. A wafer boat (10) configured to support a plurality of wafers and placed on a base (12) of a vertical batching furnace, the base (12) having a flat support surface (14), wherein the wafer boat (10) defines a central wafer boat axis (16) that extends vertically when the wafer boat (10) is placed on the base (12), wherein the wafer boat (10) comprises: - Support ring (18), which defines the flat bottom end surface (20) of the wafer boat (10); as well as - Alignment ring (22) concentric with support ring (18), The base (12) has a plurality of alignment elements (24) on its support surface (14) or on the bottom side of its alignment ring (22). The alignment elements protrude upward from the support surface (14) or downward from the alignment ring (22). The other of the support surface (14) and the alignment ring (22) has a plurality of alignment openings (26) configured to accommodate the plurality of alignment elements (24). The support ring (18) protrudes downward beyond the alignment ring (22) in the direction of the central wafer boat axis (16), such that when the wafer boat (10) is placed on the base (12), the support ring (18) is supported on the support surface (14), while the alignment ring (22) is spaced apart from the support surface (14) of the base (12). The support ring (18) is disposed radially outside the alignment ring (22).

2. The wafer boat according to claim 1, wherein, The support ring (18) is annular and has an inner diameter (28) and an outer diameter (30), wherein the difference between the inner diameter (28) and the outer diameter (30) is less than 10 mm.

3. The wafer boat according to claim 2, wherein, The difference between the inner diameter (28) and the outer diameter (30) is between 4 and 5 mm.

4. The wafer boat according to claim 1 or 2, wherein, The support ring (18) and the alignment ring (22) are integrally formed.

5. The wafer boat according to any one of claims 1-3, wherein, The alignment element (24) is disposed on the support surface (14) of the base (12), and the plurality of alignment openings (26) are disposed in the alignment ring (22).

6. The wafer boat according to any one of claims 1 to 3, wherein, The alignment element (24) is disposed on the support surface (14) of the base (12), and the plurality of alignment openings (26) are disposed in the alignment ring (22) and extend through the support ring (18).

7. The wafer boat according to any one of claims 1-3, wherein, The plurality of alignment openings (26) are implemented as slots (26) passing through the alignment ring (22).

8. The wafer boat according to any one of claims 1-3, wherein, The plurality of alignment openings (26) are implemented as slots (26) through the alignment ring (22) and extend through the support ring (18).

9. The wafer boat according to claim 7, wherein, Each slot (26) is a straight slot with a slot axis, wherein each slot axis extends through the alignment ring (22) and extends radially outward.

10. The wafer boat according to claim 7, wherein, Each slot (26) is a straight slot with a slot axis, wherein each slot axis extends through the center point of the alignment ring (22) and the support ring (18) and extends radially outward.

11. The wafer boat according to claim 9, wherein, The plurality of slots (26) includes three slots (26) that are circumferentially spaced at an intermediate angle of 105° to 135° along the circumference of the alignment ring.

12. The wafer boat according to claim 11, wherein, The intermediate angles are 110°, 120° and 130°.

13. The wafer boat according to any one of claims 1-3, wherein, The alignment element (24) is disposed on the alignment ring (22), and the plurality of alignment openings (26) are implemented as slots in the support surface (14).

14. The wafer boat according to claim 7, wherein, The width of each slot (26) is such that each alignment element fits tightly within its respective slot (26), thereby enabling the alignment element to move radially within the associated slot (26) and preventing movement of the alignment element in the tangential direction of the alignment ring (22).

15. The wafer boat according to any one of claims 1-3 further comprises at least two pillars (34) connected to the alignment ring (22) and extending upward from the alignment ring (22) parallel to the axis (16) of the central wafer boat, wherein each pillar (34) includes a plurality of slits for supporting a plurality of wafers.

16. The wafer boat of claim 15, further comprising at least three pillars.

17. The wafer boat according to claim 15, further comprising a top plate (36) connected to the upper ends of the at least two pillars (34).

18. The wafer boat according to claim 15, comprising a base plate (38) extending inwardly from and concentric with the alignment ring (22).

19. The wafer boat according to claim 15, wherein, The support ring (18), alignment ring (22) and base plate (38) are integrally formed.

20. The wafer boat according to any one of claims 1-3, wherein, The support ring (18) and alignment ring (22) are made of quartz.

21. An assembly for aligning and rotating a wafer boat (10), the assembly comprising: - The wafer boat (10) according to any one of claims 1-20; as well as - A base (12) comprising a flat support surface (14) and a plurality of alignment elements (24) projecting upward from the support surface (14) in a plurality of alignment openings (26) configured to be received in an alignment ring (22) or a plurality of alignment openings (26) configured to receive a plurality of alignment elements (24) on the alignment ring (22) therein.

22. The component of claim 21, wherein, The alignment element (24) is a pin that extends upward from the base support surface (14).

23. A vertical batching furnace assembly for processing wafers, comprising: - Processing chambers configured to apply heat or chemical treatment to batches of wafers; - A wafer processing space provided with the components (10, 12) according to claim 21 or 22; and - A wafer boat processing apparatus configured to transfer components (10, 12) between a wafer processing space and a processing chamber.

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