TW201300583A - Sheet wafer growth stabilization - Google Patents

Abstract

A device for forming a wafer-type wafer having a housing forming an internal chamber, and a crucible being located in the internal chamber, the crucible having a top surface. The crucible is constructed to accommodate a volume of molten material. The device also has a wafer guide positioned in the interior chamber spaced from the top surface of the crucible, the wafer guide forming a passage for the growing wafer wafer to pass.

Description

Sheet wafer growth stabilization

The present invention relates to a sheet wafer, and more particularly to an apparatus and program for forming a wafer wafer.

The germanium wafer is a building block of various semiconductor devices, such as a solar cell, an integrated circuit, and a microelectromechanical system (MEMS) device. For example, Evergreen Solar, Inc. of Marlboro, Massachusetts, USA, manufactures tantalum wafers from crucibles that are introduced into a crucible with two thin wires. Solar battery. This type of wafer may be referred to as "Filament sheet wafers" and is referred to in the industry as a STRING RIBBON ^(TM ) wafer.

Ribbon pulling technology uses proven processes to produce high-quality silicone crystals, but wafer-type wafers produced by this process technology are distorted to some extent (also known in the art). To "bend").

In accordance with an embodiment of the invention, a device for forming a wafer wafer has a housing defining an interior chamber, and a crucible is located in the interior chamber, and the crucible has a top surface. The crucible is constructed to accommodate a volume of molten material. The apparatus also has a wafer guide positioned in the interior chamber spaced from the top surface of the crucible, the wafer guide forming a passage for the growing wafer wafer to pass.

The apparatus can also have an afterheater zone located to control the temperature in the internal chamber. The wafer guide can be at least partially in the afterheater zone. In addition, the wafer guide can be comprised of a plurality of cylinders extending from at least two opposing surfaces of the afterheater. Alternatively, or in addition, the wafer guide can include a pair of solid members extending from at least two opposing surfaces of the afterheater.

The crucible may further comprise a molten material (eg, a polycrystalline crucible) on its top surface. The molten material forms a sheet wafer extending from the crucible as it enters and passes through the afterheater zone where it is cooled in a controlled manner and the initial cooling is very rapid. The wafer guide posts are disposed adjacent the surface of the melt, but not too close to substantially affect the cooling of the sheet (especially during the rapid initial cooling) or cause additional cooling. The further the wafer guide is placed away from the meniscus, the less stabilizing the movement of the meniscus is.

The internal chamber can thus be considered to have a plateau between the crucible and a rear plateau. The wafer guide is at least partially positioned in the rear plateau. The position and size of the rear plateau is determined by the molten material that the device is designed to use.

The channel is considered to have a length, a height, and a width (ie, the width is a gap between opposing wafer guides). In some embodiments, the wafer guide includes a plurality of wafer guides extending inwardly to change the width of the channel. For example, the channel can have a pair of end regions and a central region. Thus the width of the channel in the central zone may be less than the pair of end zones. Moreover, the height is preferably much smaller than the length, and/or the channel can be elongated.

The formation of the wafer guide should use materials in the device that can withstand the expected temperatures (eg, over 1200 ° C). For example, the wafer guide may be formed of at least one of tantalum carbide and graphite, among others.

According to another embodiment of the present invention, a method and apparatus for forming a wafer-type wafer is a crucible in which a molten material is added to a furnace, and a thin sheet is grown from the molten material by a pair of thin wires. Wafer. The method and apparatus pass at least a portion of the growing sheet wafer through a wafer guide member that is located in a rear plateau of the furnace. To this end, the wafer guide member forms an elongated channel for the growth of the growing wafer wafer.

In an exemplary embodiment, a sheet-type wafer furnace has an internal structure for limiting the movement of the growing wafer-type wafer to its local meniscus. This will significantly effectively mitigate or eliminate a source of potential wafer bowing. To this end, the furnace has a plurality of wafer guides strategically located near the meniscus and downstream of the meniscus. When properly positioned, the wafer guides reduce wafer movement caused by post-processes, such as transporting and withdrawing the wafer as it continues to grow. The details of the illustrative embodiments are described below.

Fig. 1 shows a film sheet wafer 10 constructed in accordance with an exemplary embodiment of the present invention. The wafer 10 can be similar to a linear twin ribbon wafer of Evergreen Solar Co., Ltd., for example, Marburg, Massachusetts, USA. To some extent similar to other wire sheet wafers, the wafer wafer 10 is generally rectangular in shape and has a relatively large surface area on its front and back sides.

The thickness of the wafer wafer 10 will vary and is very thin relative to its length and width dimensions (discussed below). Nonetheless, the wire sheet wafer 10 can be viewed as having an average thickness across the length and/or width. For example, the sheet wafer 10 may have a thickness between 80 microns and 320 microns across the width. Some embodiments have an average thickness between 100 microns and 200 microns, such as around 170 microns. The wire sheet wafer 10 may mainly include any of various crystal types, such as multi-crystalline, single crystalline, polycrystalline, microcrystalline or amorphous. Amorphous (such as 矽) and so on.

As known to those skilled in the art, the wire-sheet wafer 10 is formed from a pair of thin wires 12 (also referred to as strings) substantially encapsulated by a coffin (e.g., polycrystalline germanium or single crystal germanium). The coffin may extend slightly beyond the thin line 12 to form an edge of the sheet wafer 10. The first figure illustrates this by displaying the thin line 12 along the imaginary dotted line on the long side of the wafer 10.

For the purposes of this discussion, the wafer 10 is parallel to the distance between the edges of the thin lines 12, which is considered to be the "width" of the wafer 10. Figure 1 clearly identifies this scale. The thin lines 12 are thus considered to extend substantially perpendicular to the width of the body. Therefore, from the perspective view of Fig. 1, the two edges (or both sides) forming the width can be regarded as "left and right edges (or sides)". In a corresponding manner, Figure 1 also clearly shows the "length" dimension which is generally perpendicular to the width, i.e., substantially parallel to the thin lines 12. Further, the two edges or both sides forming the length from the perspective view of Fig. 1 can be regarded as "top side (edge) and bottom side (edge)".

The length of the wafer 10 can vary widely depending on where the automated process is processed and/or where the operator cuts the growing wafer wafer 10. Preferably, the automated process and/or operator cuts/separates the wafer wafer 10 in a manner that produces a wafer 10 that is relatively small and substantially uniform in length. The wafer 10 can have a width of a conventional size or greater than the width of a conventional wire sheet wafer known to the inventors. For example, the width of the wafer 10 may exceed about 140 mm. In some embodiments, the wafer 10 has a width of between 145 mm and 165 mm, or about 156 mm.

The process of forming a wafer wafer 10 involves many variables and complexities. In fact, in the wafer 10, these variables may somewhat unsatisfactorily cause buckling or bending of the wafer 10; a form of wafer warping. For example, some conventional thin-film wafer technologies from this growing lamella The growing wafer wafer 10 is captured by the circle 10 prior to laser dividing a smaller portion to form another wafer 10 (as shown in FIG. 1). The wafer manipulation mechanical movement moves the growing wafer 10 as it extends from the corresponding crucible of the molten material (hereinafter referred to as the meniscus, "liquid-solid interface" discussed in FIG. 2 and other figures). The base. This and other such mechanical manipulations can cause bending of the wafer 10.

If the total amount of curvature is too large, it will break more easily during and after manufacture, so that the wafer 10 generally has a small market value. For example, when used in a solar cell, the process is typically screen printing silver or some other metal on the front and back sides of the line wafer 10 (discussed in more detail later). Many conventional screen printing programs require a substantially flat wafer 10 that would otherwise destroy the very thin and fragile wafer 10. This will significantly reduce production and thus increase costs.

To understand the bend, an ideal wire sheet wafer 10 can be considered which is a perfect plane. As noted above, however, the wire sheet wafer 10 typically has a varying thickness across the body. Thus, an ideal, variable thickness line wafer wafer 10 is entirely under/between the plane of the thickest portion of the thickness. The thickest portion of the thickness can be considered to form an "ideal plane." In practice, however, regardless of the width of the wafer, the body may have portions that are undesirably curved to cause a certain edge (or side) to extend out of the ideal plane.

In an exemplary embodiment, the wire sheet wafer 10 does not have edges, faces or other portions that extend beyond the ideal plane beyond a predetermined amount of off-surface. For example, the wafer 10 must not extend beyond the ideal plane by more than about 2.5 millimeters. Therefore, wafer fabrication and quality control procedures reject any portion of the wafer that extends beyond the ideal plane by more than about 2.5 mm. For example, wafer 10 has an edge that extends approximately 2.8 millimeters from the face, which can be considered to have "a bend of 2.8 millimeters."

A method for simply determining whether a bend is less than a maximum allowable amount by placing the wafer 10 on a substantially flat conveyor belt and passing the wafer 10 through about 2.5 mm or less (i.e., the highest of the top surface) Part of the rod or element below about 2.5 mm). For example, some programs perform this test with 2.0 mm above the ideal plane. If the wafer 10 passes under the rod or element, it has acceptable curvature and can be commercialized for use in solar cells. If it can't pass under the pole, it is eliminated because it has too much bending. Most of the edges (non-faces) of the wafer 10 that are expected to fail are likely to be off-plane. The inner portion may be on the face of the wafer 10, however, there is still an off-surface condition that may cause the wafer to be scrapped.

Therefore bending is an important issue. To control the bending, the inventors have learned that the lateral movement of the wafer 10 during growth must be carefully controlled. To this end, the inventors modified the wafer growth furnace from the source to reduce bending.

Specifically, as is known to those skilled in the art, the thin-line wafers 10 are grown in a high temperature wire wafer growth furnace. Fig. 2 is a view showing a sheet type wafer fusing 14 in each embodiment of the present invention. The furnace 14 can include a housing 16 that forms a closed or sealed interior (shown in the following figures). The interior may be substantially free of oxygen (e.g., to prevent combustion) and include one or more gases, such as argon or other inert gases, which may be provided from an external source of gas. The interior includes a resistance heating crucible 18 containing molten crucibles (as shown in Figures 3-5) and other elements for growing substantially one or more crucible wafers 10 simultaneously. Although FIG. 2 shows four wafer-type wafers 10, the furnace 14 can grow fewer or more wire-sheet wafers 10 substantially simultaneously. For example, the furnace 14 can grow two wide sheet wafers 10 (also referred to as "crystal sheets 10").

The housing 16 can include a door 20 to permit detection of the interior and its components, as well as one or more additional viewing windows 22. The housing 16 also has a material for guiding, for example, bismuth particles. The inlet of the substance (not shown) is brought into the interior of the housing 16 to the crucible 18. It should be noted that the foregoing discussion of the tantalum material and the tantalum wafer 10 is illustrative and is not meant to limit all embodiments of the present invention. For example, the sheet wafer 10 such as metal, glass, ceramic or alloy may be formed of other materials.

3 is a partially cutaway perspective view showing a furnace 14 having a portion of the casing 16 removed, and FIG. 4 is a cross-sectional view showing a growth system having the casing 16 removed. As described above, in the interior of the housing 16, the furnace 14 includes a crucible 18 that houses a molten material 24.

In one embodiment, the crucible 18 can have a substantially flat upper surface that can support or contain the molten material 24 (e.g., molten polycrystalline crucible). Alternatively, other embodiments of the crucible 18 (not shown) may have walls for receiving the molten material. The crucible 18 includes a fine wire hole (not shown) that allows one or more thin wires 12 to pass through the crucible 18. When the thin wires 12 pass through the crucible 18, the surface meniscil of the respective surfaces is solidified, thereby forming the growing flakes between the respective relatively thin wires 12. Wafer 10. To facilitate wafer side-by-side growth, the crucible 18 is elongated and has an area for growing the sheet wafer 10 along its length in a side-by-side configuration. However, in other embodiments, the wafers 10 can be grown face to face.

In order to at least partially control the temperature profile inside it, the furnace 14 has an insulation formed in the housing 16 based on the heat demand of the zone. For example, the formation of the heat insulator is based on 1) a region containing the molten material 24 (ie, the crucible 18), and 2) a region containing the generated wafer-type wafer 10 (postheater 28, The combined patent application number 13/015,047 is discussed in more detail). To this end, the insulation comprises a thermally insulated base 26 forming a range containing the crucible 18 and the molten material 24, and a heat exchanger 28 located on the insulated base 26 (as viewed from a perspective view).

The afterheater 28 is important for the bending problem, which is where the wafer 10 just formed is cooled from very high temperatures to ambient temperatures. Ideally, the rate of change of the cooling caused by the afterheater 28 across the X and Y directions of the wafer 10 is substantially constant. To this end, the inventors constructed the afterheater 28. In addition, reference is made to the aforementioned incorporated patent application Serial No. 13/015,047 for further details of various embodiments of the afterheater 28.

In certain embodiments, the furnace 14 may also include a gas cooling system that supplies gas from a source of external gas (not shown) through a gas-cooled manifold to the gas nozzle 30. The gas cooling system can provide a gas to further cool the growing sheet wafer 10 and control its thickness. For example, as shown in Figures 3-5, in the range above the crucible 18, the gas cooling nozzles 30 may face the growing sheet wafer 10, i.e., toward the aforementioned reference from the melt Extending and containing the meniscus of the wafer 10.

To mitigate wafer bowing, the furnace 14 has a plurality of strategies for positioning the wafer guides 32 in its interior. To this end, in each channel of the furnace 14, the wafer guides 32 are positioned very close to their respective meniscus (i.e., close to where there is a meniscus when operating), but not too close On its corresponding meniscus. As discussed in more detail later, the wafer guides 32 are positioned to reduce their effect on the temperature profile in the furnace 14 and still stabilize the growing wafer 10 as much as possible.

Specifically, Figures 3-5 each show a pair of wafer guides 32 constructed in accordance with an illustrative embodiment of the present invention. These wafer guides 32 substantially mechanically retain the growing wafer 10 in its desired position, i.e., near the meniscus from which the molten material 24 extends. In other words, the wafer guides 32 are ideally compensated for subsequent mechanical manipulations of the substrate that will move the wafer 10 (of the growing wafer 10) so that the wafer 10 is on the meniscus. Therefore, the wafer guides 32 can limit the wafer to a Move in dimension or two dimensions, that is, perpendicular and/or parallel to the length of the meniscus.

While Figures 3-5 show only portions, Figure 6A shows a complete front view of a wafer guide. The wafer guide 32 is mechanically coupled at its end 34 to the interior surface of the afterheater 28 and has a body 36 that spans between its ends 34. In order to have an additional support structure, certain embodiments of the wafer guide 32 are secured to the afterheater 28 in other regions, such as in the vicinity of the central portion of the body 36. As discussed below, the growing wafer 10 can contact the surface of any of the respective leads 32. However, in order to reduce contact, the inventors have designed the height of the wafer guides 32 to be extremely small relative to their length.

The height of the guides 32 can be selected as a function of the width of the channel and vice versa. For example, it is contemplated that a channel 38 having a larger width (e.g., twice the average width of the wafer 10) and a larger height is associated with a channel 38 having a smaller width and a smaller height. Under the operation.

The wafer guides 32 should be formed of a material that is generally expected to be resistant to high temperatures in the wafer furnace 14. For example, this temperature typically exceeds 1400 °C. Thus, among other things, the wafer guides 32 can be formed of graphite or tantalum carbide.

As shown in the other figures, the two main inner walls of the afterheater 28 each support a wafer guide 32. Thus, each wafer guide 32 is directly opposite a corresponding wafer guide 32 to form an elongated channel 38 such that the growing wafer 10 can pass. This channel 38 can be closed at its end or open at its end. In the exemplary embodiment, the channel 38 provides a very small gap for the wafer 10 to pass through. For example, if the wafer 10 has a maximum thickness of about 190 microns, the wafer channel 38 may have a thickness of only about 195 microns to 200 microns. Of course, other embodiments may have a wide wafer channel 38.

Thus the channel 38 can have a uniform width. Thus, the channel width should be greater than the maximum expected thickness of the growing wafer 10. As noted above, however, many sheet wafers 10, including those shown in Figure 1, have varying thickness across their width. Thus, the wafer guides 32 can be secured to the afterheater 28 to vary the thickness of the channel 38 across its length. For example, the end of the wire sheet wafer 10 may be thicker than the same wafer 10 along its longitudinal axis (i.e., near the center of its width). Thus, the exemplary embodiment can constitute the wafer guides 32 such that the channel 38 is wider at its end than near its center. Thus, in this example, the channel thickness decreases from one end 34 across the center.

In fact, the channel thickness can be varied at many locations to more closely track the varying thickness of the growing wafer 10. The inventors expect that such varying thickness channels 38 will provide improved results during the wafer growth process. Of course, based on the expected size and shape of the wafer 10 in the growth (depending on the nature of the molten material used to form the wafer 10), those skilled in the art will pre-set the dimensions and geometry of the channel 38.

As described above, the wafer guides 32 can be applied to the multi-channel wafer growth furnace 14. For example, in the manner described, each channel of the four-channel wafer furnace 14 preferably has a wafer guide 32 for limiting the movement of the growing wafer 10 in the manner described above. Figure 6B shows an embodiment in which the channels of the two-channel wafer furnace 14 have wafer guides 32 to reduce wafer bowing in a desired manner. It should be noted that Figure 6B shows only one side of the afterheater 28. Accordingly, the correspondingly disposed side of the afterheater 28 has a corresponding wafer guide 32 to complete the necessary structure to substantially limit wafer movement.

Many design limitations suggest a way to use wafer guides 32 to reduce wafer bowing. First, setting an additional material undesirably close to the meniscus will act as a hindrance to the crystal. Round 10 properly cooled insulation. This produces defective wafers that are too thin and fragile. In the face of this problem, the inventors have found that reducing the size of the wafer guides 32 can alleviate the cooling problem while still providing the same function.

Accordingly, the inventors have discovered that a plurality of carefully positioned cylinders/pins/members (hereinafter referred to as "cylinders 40") extending from the afterheater wall can provide corresponding benefits (i.e., the formation of the cylinders 40) Instead of using a continuous wafer guide 32, a non-continuous wafer guide). In fact, if properly positioned (discussed below), the discontinuous wafer guide 32 can achieve the benefit of suppressing undesired wafer movement without significantly affecting the temperature profile. To this end, Figure 7 shows a heater wall after a two-channel wafer furnace 14 implementing this type of wafer guide 32. As with Figure 6A, the corresponding half of the afterheater 28 acts in conjunction with the portion of the afterheater 28 to form a channel 38 that limits undesired wafer movement.

To more closely match the varying thickness of the wafer 10, the posts 40 can extend a different distance from the afterheater wall to effectively form a variable thickness channel 38. Moreover, the pillars 40 can have different surface areas for contacting the growing wafer wafer 10. Each of the cylinders 40 can have a corresponding, directly oppositely mounted cylinder. Alternatively, or in addition, the posts 40 may be offset from each other on each side.

It should be noted that this discussion refers to the plurality of wafer guides 32 on the walls of the afterheater 28 as an example. However, in other embodiments, only one wafer guide 32 is disposed on a wall of the afterheater 28. This approach is particularly effective when the physical subsequent manipulation of the growing wafer 10 is only propelled in one direction (e.g., toward the wafer guide). In addition, in other embodiments, one half of the afterheater 28 may have a solid wafer guide, and the other half of the afterheater 28 may have a discontinuous wafer guide 32 (as shown in FIG. 7). Show). Although other embodiments There may be non-continuous and continuous wafer guides 32 on the same side of the afterheater 28.

Moreover, some embodiments do not mount the wafer guides 32 to the afterheater 28. For example, the wafer guides 32 can be mounted directly to the interior chamber wall. Alternatively, the wafer guides 32 may be only partially in the afterheater 28.

Regardless of the type, if the setting is too close to the meniscus, the wafer guide 32 may still have a negative impact on the temperature profile. This may cause someone to place the wafer guides 32 too far away from the meniscus to fully stabilize the wafer 10. In the face of this problem, the inventors have discovered an intermediate point within the furnace 14 that optimizes the stabilization of the wafer 10 without significantly affecting the temperature profile.

Specifically, FIG. 8 graphically shows, by way of example, a temperature profile in the operation wafer foiler 14 in which the linear wafer-type wafer 10 is formed in a polycrystalline body. In this example, the furnace 14 moves the wafer 10 upward at a rate of about 24 mm/min. The x-axis shows the time the wafer moved relative to the top surface of the meniscus, while the y-axis shows the temperature at the corresponding location in the furnace 14 at that time.

As shown, the temperature on the top of the meniscus is close to 1400 °C. The temperature then drops sharply to about 1250 ° C immediately, which is maintained at a plateau of about 15 seconds to about 16 seconds. The region in the furnace 14 where the temperature drops sharply (from about 0 seconds to about 3 seconds) is referred to herein as the "sudden zone", and the temperature in the furnace 14 is stable (approximately from about 3 seconds to about 19 seconds). The area is referred to herein as the "stationary area." The plateau zone in this furnace 14 generally corresponds to the inner region of the furnace under the post-heater 28 (as viewed from a perspective view). In the plateau, the heat flow between the ribbon wafer and the environment is a very delicate balance controlled by the radiant heat flow. Thus, there is only some micro-cooling in the area of the furnace 14. Therefore, the placement of the wafer guides 32 in this region may interfere with this delicate radiant heat balance.

From about 19 seconds to about 60 seconds, the temperature drops substantially linearly. In fact, the The wafer 10 is generally linearly cooled much longer than 60 seconds (e.g., 10 minutes). For the sake of convenience, this illustration thus ends in 60 seconds. This linearly falling region is referred to herein as the "post-stationary region." Thus, to avoid this plateau, the wafer guide 32 of this illustrative example is positioned in a post-stationary zone that corresponds to about 19 seconds to about 60 seconds, or more. To more stabilize the growing wafer 10 and still reduce the effects of the thermal profile, the wafer guides 32 are positioned as close as possible to the plateau (e.g., in a post-stationary region that approximately corresponds to 21 seconds to 22 seconds). In another example, the wafer guides 32 can be positioned in a rear plateau of about 29 seconds. This area may be the base/inlet of the afterheater 28. In a furnace 14, for example, this area is spaced about 22 mm from the surface of the crucible 18. Although the wafer guide 32 should stabilize the growing wafer 10 at any distance from the meniscus, it is expected that the wafer guides 32 are preferred when in the lower/early stage of the back plateau. which performed.

Of course, the particular temperatures and locations of the wafer guides 32 are discussed by way of example only. Since the person skilled in the art determines the placement of the wafer guides 32 based on the material from which the wafer 10 is fabricated, the actual position varies depending on the material contained in the crucible 18.

The exemplary embodiment thus mechanically limits some undesirable movement of the sheet wafer 10 as it is grown by the crucible 18. In many prior art wafer wafer growth procedures, this should alleviate an important source of intrinsic bending.

While the invention has been described above in terms of the preferred embodiments, the invention is not intended to limit the invention, and the invention may be practiced without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

10‧‧‧Sheet wafers, wafers

12‧‧‧ Thin line

14‧‧‧Furn

16‧‧‧Shell

18‧‧‧ 坩 pot

20‧‧‧

22‧‧‧ observation window

24‧‧‧ molten material

26‧‧‧Insulated base

28, 28a, 28b‧‧‧ after heat exchanger

30‧‧‧ gas cooling nozzle

32‧‧‧ Wafer Guides

34‧‧‧End

36‧‧‧ Subject

38‧‧‧ passage

40‧‧‧Cylinder

Fig. 1 shows a sheet-type wafer constructed in accordance with an exemplary embodiment of the present invention.

Figure 2 is a partial perspective view showing a wafer type wafer growth system in an exemplary embodiment of the present invention.

Fig. 3 is a partially cutaway perspective view showing a sheet-type wafer growth system in which a part of the casing is removed in Fig. 2 of the present invention.

Figure 4 is a cross-sectional view showing a wafer type wafer growth system in various embodiments of the present invention having a guide system in the afterheater.

Figure 5 is a partial close up view showing the furnace.

6A and 6B show one of two uses of a wafer guide according to an exemplary embodiment of the present invention.

Figure 7 is a diagram showing a wafer guide of a second configuration in accordance with an exemplary embodiment of the present invention.

Figure 8 is a graph showing the temperature profile in the same wafer furnace.

10‧‧‧Sheet wafers, wafers

12‧‧‧ Thin line

14‧‧‧Furn

16‧‧‧Shell

18‧‧‧ 坩 pot

20‧‧‧

24‧‧‧ molten material

26‧‧‧Insulated base

28, 28a, 28b‧‧‧ after heat exchanger

32‧‧‧ Wafer Guides

34‧‧‧End

Claims (15)

A device for forming a wafer-type wafer, the device comprising: a casing forming an internal chamber; a crucible in the internal chamber, and the crucible having a top surface, the crucible is configured to accommodate a a volume of molten material; and a wafer guide located in the interior chamber spaced apart from the top surface of the crucible, the wafer guide forming a passage for the growing wafer wafer to pass. The apparatus of claim 1, further comprising an afterheater zone located for controlling a temperature in the internal chamber, the wafer guide being at least partially located in the afterheater zone. The device of claim 2, wherein the wafer guide comprises a plurality of cylinders extending from at least two opposing surfaces of the afterheater. The device of claim 2, wherein the wafer guide comprises a pair of elongate members extending from at least two opposing surfaces of the afterheater. The device of claim 1, wherein the internal chamber comprises a plateau and a rear plateau, the plateau is between the crucible and the rear plateau, and the wafer guide is at least partially It is located in the rear plateau. The device of claim 1, wherein the channel has a length and a width, and the wafer guide includes a plurality of wafer guides extending inwardly to change the width of the channel. The device of claim 6, wherein the channel has a pair of end regions and a central region, the channel having a width less than the pair of end regions. . The device of claim 1, wherein the channel has a length, a width, and a height that is less than the length. The device of claim 1, wherein the internal chamber comprises a plateau region and a rear plateau region, and the wafer guide is at least partially positioned in the rear plateau region, wherein the rear plateau region is The molten material is determined. The device of claim 1, wherein the channel is elongated. The device of claim 1, wherein the wafer guide comprises at least one of tantalum carbide and graphite. A method of forming a wafer-type wafer, the method comprising: adding a molten material to a crucible in a furnace; growing a sheet-type wafer from the molten material by a pair of thin wires; and making the grown wafer-shaped wafer At least a portion of the passage formed by the wafer guide member in the rear plateau of the furnace is elongated to allow passage of the growing wafer wafer. The method of claim 12, wherein the growing wafer-type wafer contacts the wafer guide when the growing wafer-type wafer passes through the channel. The method of claim 12, wherein the wafer guide comprises a plurality of cylinders. The method of claim 12, further comprising an afterheater spaced from the crucible, the wafer guide being at least partially in the afterheater zone.