Vertical boat

Abstract

To suppress slippage and particle generation in semiconductor wafers. [Solution] The wafer boat 4 has a top plate 41, a bottom plate 42, support columns 43A to 43C, and a wafer support portion 44. One end of each support column 43A to 43C is fixed to the top plate 41 and the other end is fixed to the bottom plate 42. The wafer support portion 44 protrudes from the sides of the support columns 43A to 43C and supports the semiconductor wafer W. The wafer support portion 44 is pivotable within a predetermined angular range AR relative to the support columns 43A to 43C.

Description

Technical Field

[0005]

[0001] The present invention relates to a vertical boat for a semiconductor heat treatment furnace.

Background Art

[0002] Conventionally, heat treatment processes such as LP-CVD (low-pressure chemical vapor deposition) and annealing of semiconductors have been performed using a vertical semiconductor heat treatment furnace. In a vertical semiconductor heat treatment furnace, a vertical boat that supports a plurality of semiconductor wafers is used.

[0003] Conventionally, in a vertical boat, slip and particles generated in a semiconductor wafer have been suppressed by R-shaped machining of the groove claw corners that support the semiconductor wafer and by improving the surface roughness and machining accuracy (see Patent Documents 1 and 2 below).

[0004] Also, in a wafer loading boat for a vertical heat treatment furnace in which a large number of pairs of two beams are horizontally held at a required interval in the longitudinal direction of the support columns, a configuration in which each beam is held so as to be rotatable with respect to the support columns is known (see Patent Document 3 below).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In conventional vertical boats, stress is generated at each support position where the semiconductor wafer is mounted, making it difficult to suppress semiconductor wafer slippage. Furthermore, it is difficult to suppress the generation of particles due to stress concentration caused by thermal deformation of the semiconductor wafer.

[0007] This invention was made to solve the above-mentioned problems and aims to suppress slippage and particle generation in semiconductor wafers. [Means for solving the problem]

[0008] The vertical boat of disclosure is, The tabletop and The base plate and A support column having one end fixed to the top plate and the other end fixed to the bottom plate, A wafer support portion that protrudes from the side of the aforementioned support column and supports the semiconductor wafer, It has, The wafer support portion is pivotable within a predetermined angular range relative to the support column. It is. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress slippage and particle generation in semiconductor wafers. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing a semiconductor processing apparatus 1, which is an example of a semiconductor processing apparatus to which the vertical boat according to this embodiment can be applied. [Figure 2] This figure shows an example of the overall configuration of wafer boat 4. [Figure 3] This figure shows an example of a semiconductor wafer being placed on wafer boat 4. [Figure 4] This figure shows an example of the structure of the wafer support section 44. [Figure 5] This figure shows the structure of the support column 43A and an example of how the wafer support part 44 is attached to the support column 43A. [Figure 6] FIG. 1 is a view showing an example of the swing range of the wafer support portion 44. [Figure 7] FIG. 2 is a view showing a modified example of the wafer support portion 44. BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, an example of a vertical boat for a semiconductor processing apparatus according to the present embodiment will be described with reference to the drawings.

[0012] <Configuration of Semiconductor Processing Apparatus> FIG. 1 is a cross-sectional view showing a semiconductor processing apparatus 1 which is an example of a semiconductor processing apparatus to which the vertical boat according to the present embodiment can be applied.

[0013] The vertical semiconductor processing apparatus 1 shown in FIG. 1 includes a cylindrical furnace tube 2 as a whole. This furnace tube 2 has an opening 3 at the lower part, and a large number of semiconductor wafers W (substantially disk-shaped) mounted on the wafer boat 4 are inserted and removed through this opening 3 in a configuration. The "vertical boat" of the present invention can be applied to the wafer boat 4 as an example. In FIG. 1, the structure of the wafer boat 4 is shown in a simplified manner.

[0014] The furnace tube 2 is formed of quartz glass or silicon carbide (SiC), and a processing space 5 is formed inside it. In the processing space 5, for example, two gas introduction pipes 6 having different lengths are provided, and a predetermined gas (for example, silane gas) can be introduced into the processing space 5.

[0015] The gas introduction pipe 6 is a pipe having a gas inlet 6a and a gas outlet 6b, and is formed in an L shape in the example shown in FIG. 1. That is, the gas introduction pipe 6 is composed of a horizontal portion 6h arranged horizontally in the furnace tube 2, a bent portion 6c bent at about 90 degrees, and a vertical portion 6v arranged vertically in the furnace tube 2.

[0016] In the semiconductor processing apparatus 1, near the bottom of the furnace tube 2, a lifting device 10 for opening and closing the opening 3 is provided, and a boat table 11 for supporting the wafer boat 4 is placed thereon. Around the furnace tube 2, a heater 12 for heating the furnace tube 2 is provided. At the top of the furnace tube 2, an exhaust port 13 for the processing gas is provided.

[0017] <Heat treatment of semiconductor wafers in the semiconductor processing apparatus 1> In the semiconductor processing apparatus 1 configured as described above, first, the wafer boat 4 on which a large number of semiconductor wafers W are placed is placed on the boat table 11 placed on the lifting device 10 and stored in the furnace tube 2 heated by the heater 12.

[0018] Then, the temperature inside the furnace tube 2 is further increased. For example, a processed gas doped with heated boron is introduced into the furnace tube 2 from the gas introduction pipe 6. The introduced processed gas deposits a silicon film on the semiconductor wafer W, and then the processed gas is exhausted from the exhaust port 13.

[0019] <Overall structure of the wafer boat 4> FIG. 2 is a diagram showing an example of the overall structure of the wafer boat 4. FIG. 2 shows the upper surface (upper part of FIG. 2) and the side surface (lower part of FIG. 2) of the wafer boat 4. As shown in FIG. 2, the wafer boat 有 4 has a top plate 41, a bottom plate 42, and supports 43A to 43C.

[0020] The top plate 41 and the bottom plate 42 have a substantially disc shape and face each other with a gap therebetween. In this example, the top plate 41 and the bottom plate 42 have a substantially disc shape with the same diameter and the central axes coinciding. The central axis of the top plate 41 and the bottom plate 42 is the central axis 40.

[0021] The supports 43A to 43C have a substantially cylindrical shape extending parallel to the central axis 40. Each of the supports 43A to 43C has one end (upper end) fixed to the top plate 41 and the other end (lower end) fixed to the bottom plate 42. In this example, the supports 43A to 43C are arranged at equal intervals at three positions on a concentric circle centered on the central axis 40 when viewed in the direction of the central axis 40.

[0022] The wafer boat 4 is placed on the boat table 11 (see Figure 1) with one side of the bottom plate 42 (the side opposite to the top plate 41) facing downwards (in the direction of gravity). In this case, the top plate 41 and bottom plate 42 have a roughly circular surface that is horizontal, and the support columns 43A to 43C are vertical.

[0023] Each of the support columns 43A to 43C has multiple wafer support portions 44. For example, the multiple wafer support portions 44 of support column 43A are arranged in a direction parallel to (perpendicular to) the central axis 40 and are members that protrude from the inner side surface of support column 43A toward the central axis 40. Similarly, the multiple wafer support portions 44 of support columns 43B and 43C are also arranged in a direction parallel to (perpendicular to) the central axis 40 and are members that protrude from the inner side surface of support columns 43B and 43C toward the central axis 40, respectively.

[0024] Each of the support columns 43A to 43C has the same number of wafer support sections 44. In this example, each of the support columns 43A to 43C has 25 wafer support sections 44. The Nth wafer support section 44 from the bottom (N=1 to 25) of each of the support columns 43A to 43C are at the same height and form a support section that horizontally supports one semiconductor wafer at three points. Therefore, in this example, the support columns 43A to 43C can support a maximum of 25 semiconductor wafers.

[0025] <Semiconductor wafer placed on wafer boat 4> Figure 3 shows an example of a state in which semiconductor wafers are placed on a wafer boat 4. As shown in Figure 3, semiconductor wafers W are placed horizontally by wafer support parts 44 provided on the pillars 43A to 43C of the wafer boat 4. In this example, 25 semiconductor wafers W are placed in a state in which they are supported at three points by the wafer support parts 44 on the pillars 43A to 43C.

[0026] <Structure of wafer support section 44> Figure 4 shows an example of the structure of the wafer support section 44. Figure 4 shows a top view 44a, a side view 44b, and a front view 44c of the wafer support section 44. The wafer support section 44 has a support member 51 that is roughly rectangular in shape and a rotating shaft 52 that is roughly cylindrical in shape.

[0027] The wafer support section 44 is rotatably attached to the support columns 43A to 43C by inserting the rotating shaft 52 into holes (see Figure 5) provided in the support columns 43A to 43C.

[0028] The support member 51 is provided with a curved surface portion 51a that is convex upward and has curvature on the portion opposite to the rotation axis 52 (the tip portion). In this example, the curved surface portion 51a is a cylindrical (or elliptical) curved surface portion that has curvature when viewed from the side of the wafer support portion 44. The support member 51 supports the semiconductor wafer W with the upper surface of the curved surface portion 51a. Because the portion of the support member 51 that supports the semiconductor wafer W is the curved surface portion 51a, localized stress concentration can be suppressed.

[0029] The curvature of the curved portion 51a is, for example, 10 mm or more. This suppresses scratches and particle generation on the semiconductor wafer W caused by the curved portion 51a. Alternatively, the curvature of the curved portion 51a is, for example, 20 mm or less. This suppresses scratches and particle generation on the semiconductor wafer W when the semiconductor wafer W deforms and the corners of the tip of the support member 51 come into contact with the semiconductor wafer W. For these reasons, it is preferable that the curvature of the curved portion 51a be between 10 mm and 20 mm.

[0030] The width w1 (depth when viewed from the side) of the curved portion 51a is set to, for example, 10 mm or more and 20 mm or less. This makes it possible to alleviate (suppress) stress concentration when supporting the semiconductor wafer W.

[0031] The surface roughness (Ra: arithmetic mean roughness) of the curved portion 51a is preferably, for example, 0.8 μm or less. This helps to suppress scratches on the back surface of the semiconductor wafer W that is being supported. Alternatively, the surface roughness of the curved portion 51a is preferably, for example, 0.2 μm or more. This helps to suppress the back surface of the semiconductor wafer W from sticking to the surface of the curved portion 51a.

[0032] The surface roughness of the curved portion 51a may be adjusted not on the entire surface of the curved portion 51a, but only on the portion of the curved portion 51a that is in contact with the semiconductor wafer W (the upper part of the curved portion 51a) by polishing or the like.

[0033] Furthermore, the positions of the support columns 43A to 43C and the position of the curved portion 51a of the wafer support portion 44 are set so that the curved portion 51a contacts an appropriate area on the back surface of the semiconductor wafer W. For example, it is preferable to configure the curved portion 51a to be located in the region between a circle whose center coincides with the semiconductor wafer W and whose radius is 50% of the radius of the semiconductor wafer W, and a circle whose center coincides with the semiconductor wafer W and whose radius is 90% of the radius of the semiconductor wafer W.

[0034] <Structure of support column 43A and attachment of wafer support section 44> Figure 5 shows an example of the structure of column 43A and the attachment of the wafer support part 44 to column 43A. In Figure 5, the column 43A and the wafer support part 44 are shown from a direction perpendicular to the plane containing the central axis of column 43A and the central axis 40 shown in Figures 2 and 3. The structure of column 43A and the attachment of the wafer support part 44 to column 43A will be described below, but the same applies to the structure of columns 43B and 43C and the attachment of the wafer support part 44 to columns 43B and 43C.

[0035] The support column 43A is provided with multiple (for example, 25) substantially cylindrical holes 61 that engage with the rotation axis 52 of the wafer support portion 44, arranged in the longitudinal direction of the support column 43A (along the central axis 40 shown in Figures 2 and 3). The holes 61 are through holes extending in a direction perpendicular to the longitudinal direction of the support column 43A (for example, in a direction perpendicular to the central axis 40 shown in Figures 2 and 3).

[0036] By inserting the rotation axis 52 of the wafer support portion 44 into each of the holes 61, multiple wafer support portions 44 can be rotatably attached to the support column 43A. As a result, the wafer support portion 44 can swing by rotating around an axis (the central axis of the rotation axis 52) that is substantially parallel to the direction in which the wafer support portion 44 protrudes from the side of the support column 43A (the lateral direction in Figure 5).

[0037] Furthermore, in the support column 43A, rotation stoppers 62 are provided at the lower part of each hole 61. This allows the angle of oscillation of the wafer support 44 to be adjusted. The adjustment of the oscillation range of the wafer support 44 will be described later (see, for example, Figure 6).

[0038] Furthermore, the wafer support portion 44 attached to the rotation axis 52 of the support column 43A may be configured to be removable. In other words, the wafer support portion 44 may be configured to be detachable from the support column 43A. This makes it possible to replace the wafer support portion 44 on the support column 43A. As a result, even if a malfunction occurs in some of the wafer support portions 44, only the malfunctioning wafer support portion 44 can be replaced. Therefore, costs can be reduced.

[0039] <Range of oscillation of wafer support part 44> Figure 6 shows an example of the oscillation range of the wafer support 44. In Figure 6, the view of the support column 43A and the wafer support 44 from the central axis 40 shown in Figures 2 and 3 is shown. The oscillation range of the wafer support 44 at support column 43A will be explained, but the same applies to the oscillation range of the wafer support 44 at support columns 43B and 43C.

[0040] The rotation-stopping portion 62 has an upper shape (semi-circular shape) obtained by cutting a cylindrical shape having a central axis parallel to the central axis of the hole portion 61 (approximately cylindrical) with a horizontal plane higher than the central axis of that cylindrical shape. In other words, the rotation-stopping portion 62 has a curved surface that is convex upward when viewed in the direction of the central axis of the hole portion 61 (approximately cylindrical). Furthermore, the rotation-stopping portion 62 is positioned such that its upper end is slightly below the lower end of the hole portion 61 (rotation axis 52), for example, by a gap of 0.1 mm to 0.5 mm.

[0041] As a result, when the wafer support portion 44 rotates to a certain extent around the rotation axis 52 from a horizontal position, the lower surface of the wafer support portion 44 comes into contact with the rotation stopper portion 62, preventing it from rotating any further. Therefore, the oscillation of the wafer support portion 44 relative to the support column 43A can be limited to a predetermined angular range.

[0042] For example, when the wafer support portion 44 rotates counterclockwise around the rotation axis 52 from a horizontal position to an inclination angle of 71 in Figure 6, the lower surface of the wafer support portion 44 comes into contact with the rotation stopper portion 62. Also, when the wafer support portion 44 rotates clockwise around the rotation axis 52 from a horizontal position to an inclination angle of 72 in Figure 6, the lower surface of the wafer support portion 44 comes into contact with the rotation stopper portion 62. In other words, the wafer support portion 44 is oscillating (rotating) within an angular range AR (a predetermined angular range) between inclination angles 71 and 72.

[0043] The width (size) of the angular range AR is set to, for example, 0.5° or more. This allows the wafer support portion 44 to swing effectively, suppressing scratches on the back surface of the semiconductor wafer W or the generation of particles due to deformation of the semiconductor wafer W during heat treatment.

[0044] Furthermore, the width (size) of the angle range AR is set to, for example, 6° or less. This prevents the support member 51 from tilting too much and causing the corners of the support member 51 to come into contact with the semiconductor wafer W. Therefore, it is possible to prevent scratches on the back surface of the semiconductor wafer W and the generation of particles. In addition, it is possible to prevent the semiconductor wafer W from falling due to the support member 51 tilting too much.

[0045] Therefore, it is preferable that the width (size) of the angular range AR be, for example, 0.5° or more and 6° or less.

[0046] The shape of the rotation-stopping portion 62 is not limited to a semi-circular shape, but can be any shape. However, it is preferable that the portion of the rotation-stopping portion 62 that contacts the lower surface of the wafer support portion 44 be curved. This helps to suppress the generation of particles.

[0047] <Modified example of wafer support section 44> Figure 7 shows a modified example of the wafer support portion 44. In the example in Figure 4, a configuration in which the curved portion 51a is provided at the tip of the support member 51 was described, but the position in which the curved portion 51a is provided is not limited to the tip of the support member 51. For example, as shown in Figure 7, the position in which the curved portion 51a is provided may be on the side of the support column 43A (base end side) from the tip of the support member 51.

[0048] Furthermore, although the case in which the support member 51 is a substantially rectangular flat plate has been described, the support member 51 is not limited to a substantially rectangular flat plate. For example, the support member 51 may be a substantially circular disc-shaped member or a rod-shaped member.

[0049] Furthermore, although the configuration described above has shown that the curved portion 51a of the support member 51 is a cylindrical curved surface with curvature when viewed from the side of the wafer support portion 44, the curved portion 51a may also be a spherical (including ellipsoidal) curved surface with curvature when viewed from the side and front of the wafer support portion 44.

[0050] <Modified example of a rocking structure> Although a configuration in which holes 61 are provided in the support columns 43A to 43C and a rotating shaft 52 is provided in the wafer support portion 44 has been described, a configuration in which the rotating shaft 52 is provided in the support columns 43A to 43C and the holes 61 are provided in the wafer support portion 44 is also possible.

[0051] <Modified versions of support posts 43A-43C> Although we have described a configuration in which the wafer boat 4 has three support pillars (pillars 43A to 43C) as multiple support pillars, the number of support pillars that the wafer boat 4 has may be two or four or more.

[0052] <Modified example of gas introduction pipe 6> The gas inlet pipe 6 is not limited to the L-shape shown in Figure 1; it may also be straight. Furthermore, the gas inlet pipe 6 is not limited to the L-shape or straight shape; for example, it may have a shape that is bent at multiple points. The shape of the gas inlet pipe 6 to be used is determined according to the structure of the semiconductor processing apparatus (e.g., semiconductor processing apparatus 1) to which the gas inlet pipe 6 is applied.

[0053] This specification contains at least the following:

[0054] (1) The tabletop and The base plate and A support column, one end of which is fixed to the top plate and the other end of which is fixed to the bottom plate, A wafer support portion protrudes from the side of the above-mentioned support column and supports the semiconductor wafer, It has, The wafer support portion described above is pivotable within a predetermined angular range relative to the support column. Vertical boat.

[0055] (2) (1) The vertical boat described above, The width of the above-mentioned specified angle range is 0.5° or more and 6° or less. Vertical boat.

[0056] (3) (1) or (2) a vertical boat, The wafer support portion described above is pivotable by rotation around an axis substantially parallel to the direction in which the wafer support portion protrudes from the side surface of the support column. Vertical boat.

[0057] (4) A vertical boat as described in any one of (1) to (3), The portion of the wafer support section that supports the semiconductor wafer is curved. Vertical boat.

[0058] (5) (4) The vertical boat described above, The portion of the wafer support portion that supports the semiconductor wafer is the tip of the wafer support portion. Vertical boat.

[0059] (6) A vertical boat as described in any one of (1) to (5), The surface roughness of the portion of the wafer support section that supports the semiconductor wafer is 0.8 μm or less. Vertical boat.

[0060] (7) A vertical boat as described in any one of (1) to (6), The surface roughness of the portion of the wafer support section that supports the semiconductor wafer is 0.2 μm or more. Vertical boat.

[0061] (8) A vertical boat as described in any one of (1) to (7), The wafer support portion is detachable from the support column. Vertical boat. [Explanation of Symbols]

[0062] 1. Semiconductor processing unit 2 core tubes 3 aperture 4 wafer boats 5 Processing space 6. Gas inlet pipe 6b Gas outlet 6c Bend part 6h horizontal section 6v vertical part 10 Lifting device 11 Boat Table 12 Heaters 13 Exhaust vent 40 center axis 41 Top plate 42 Bottom plate 43A~43C Post 44 Wafer support section 51 Support member 51a Curved part 52 Rotation axis 61 Hole 62 Rotation stopper 71, 72 Inclination angle

Claims

1. The tabletop and The base plate and A support column having one end fixed to the top plate and the other end fixed to the bottom plate, A wafer support portion that protrudes from the side of the aforementioned support column and supports the semiconductor wafer, It has, The wafer support portion is pivotable within a predetermined angular range relative to the support column. Vertical boat.

2. A vertical boat according to claim 1, The width of the predetermined angle range is 0.5° or more and 6° or less. Vertical boat.

3. A vertical boat according to claim 1, The wafer support portion is pivotable by rotation around an axis substantially parallel to the direction in which the wafer support portion protrudes from the side surface of the support column. Vertical boat.

4. A vertical boat according to claim 1, The portion of the wafer support that supports the semiconductor wafer is curved. Vertical boat.

5. A vertical boat according to claim 1, The surface roughness of the portion of the wafer support that supports the semiconductor wafer is 0.8 μm or less. Vertical boat.

6. A vertical boat according to any one of claims 1 to 5, The wafer support portion is detachably attached to the support column. Vertical boat.

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