TWI750447B - Slicing method of semiconductor single crystal ingot - Google Patents

Abstract

A cylindrical semiconductor single crystal ingot (13) is held by holding the crystal axis of the ingot (13) different from the cylindrical central axis of the ingot (13) in a state of rotating only a predetermined rotation angle. A slicing method for a semiconductor single crystal ingot in which the ingot (13) is sliced by a cutting device (16) in a state where the ingot (13) is cut by the cutting device (16), in order to make the amount of curvature of the wafer cut by the cutting device (16) As a predetermined amount, a predetermined rotation angle when the ingot (13) is joined and held by the holder (14) and the inclination angle of the holder (14) of the cutting device (16) are determined.

Description

Slicing method for semiconductor single crystal ingot

The present invention relates to a method of slicing a semiconductor single crystal ingot such as a single crystal silicon ingot to form a semiconductor single crystal wafer such as a single crystal silicon wafer.

In the past, it has been disclosed that a single crystal member having a cleavage plane and a processing tool for cutting the single crystal member are relatively moved to cut the single crystal member with the processing tool, thereby cutting the single crystal member along a predetermined cutting plane, and processing the single crystal member. The cutting direction of the tool, with respect to the normal direction perpendicular to the intersecting line of the planned cutting plane and the cleaving plane, is set to a direction inclined toward the side in which the cutting tool discharges the chips of the single crystal member, and is set to be away from the normal direction of the cutting direction. A single crystal cutting method in which the inclination angle is set at an angle that maximizes the cutting efficiency of the single crystal member produced by the machining tool (for example, refer to Document 1: Japanese Patent Laid-Open No. 15363).

According to this single crystal cutting method, the cleavage planes of the single crystal members appear as intersecting lines A and B on the plane to be cut. In addition, the cutting direction in which the cutting efficiency is maximized is inclined from the normal lines P and Q perpendicular to the intersecting lines A and B to either the clockwise or counterclockwise side of the chip discharge direction by only the rotation angles θ ₁ and θ _{2 , respectively.} Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , Z ₆ , Z ₇ , Z ₈ directions of , θ ₃ , θ ₄ , θ ₅ , θ ₆ , θ ₇ , θ _{8 .}

When the single crystal member is lithium tantalate (LiTaO ₃ ), θ ₁ is 24 degrees, θ ₂ is 7 degrees, θ ₃ is 16 degrees, θ ₄ is 8 degrees, θ ₅ is 20 degrees, and θ ₆ is 17 degrees , θ ₇ is 16 degrees, and θ ₈ is 5 degrees.

According to the single crystal slicing method thus constituted, on the intended slicing plane of the single crystal, with respect to the normal line perpendicular to the intersecting line of the intended slicing plane and the cleavage plane, the direction of chip ejection of the single crystal member is a positive rotation angle , cutting is given from the direction in which the crystallographic characteristics of the single crystal member with this positive rotation angle and the cutting ability determined by the crimping force between the single crystal member and the processing tool become the largest, since the single crystal member is cut, the cutting removal efficiency is Each step can be increased to shorten the cutting time that takes a long time. And because the single crystal structure is not excessively deformed during processing, the cut wafer will not be bent.

On the other hand, it is disclosed that the single crystal ingot is sliced along a predetermined cutting plane by cutting the single crystal ingot with the cutting machine while the single crystal ingot and the cutting machine are relatively moved, and the crystal of the single crystal ingot is disclosed. A single crystal cutting method in which the orientation is <111> and is sliced parallel to the direction of the crystal habit line (for example, refer to Document 2: Japanese Patent Laid-Open No. 2005-231248).

According to the single crystal cutting method thus constituted, the crystal orientation of the single crystal ingot is predetermined to be <111>, and the cutting direction of the single crystal ingot is combined in the state of the cutting direction of the single crystal ingot to the crystal habit line direction of the single crystal ingot, because the cutting The machine slices the single crystal ingot parallel to the above-mentioned crystal habit line direction, which can cut the wafer with very little bending, and the cutting processing efficiency can be significantly improved. That is, the cleavage plane of a huge single crystal ingot, usually the (111) plane, is extremely difficult to obtain a cut wafer because the kinesibilities generated along the different degrees of development of the crystal plane correct the slicing direction of the single crystal ingot. The ideal wafer for bending.

In addition, a columnar semiconductor single crystal ingot is held by a retainer in a state where the crystal axis of the ingot, which is different from the cylindrical central axis of the ingot, is rotated only by a predetermined rotation angle. In the following method for slicing a semiconductor single crystal ingot in which the ingot is sliced by the above-mentioned cutting device, it is disclosed that in order to make the amount of warpage of the wafer sliced by the cutting device a predetermined amount, the predetermined value when the ingot is joined and held by the holder is determined. A method of slicing a semiconductor single crystal ingot by a rotation angle (for example, refer to Document 3: Patent Publication No. 2014-195025).

However, according to the single crystal cutting method described in the above-mentioned conventional document 1, there is no regulation regarding the angle formed by the intended cutting plane and the cleavage plane of the single crystal member, and the amount of wafer warpage after cutting the single crystal member is not limited. Know how to change bad. Furthermore, according to the single crystal cutting method shown in the above-mentioned conventional document 1, the cutting position of the single crystal member is only 5 to 25 degrees deviated from the cleavage plane, that is, with respect to the intersecting lines A and B appearing in the planned cutting plane. , there is a problem that the amount of wafer warpage cannot be sufficiently improved at such a small angle. In addition, according to the single crystal cutting method shown in the above-mentioned conventional document 1, since the single crystal member is not excessively deformed during the cutting process of the single crystal member, although the cut wafer does not bend, there is a problem of how to control the crystal. The problem with the amount of curvature of the circle.

On the other hand, according to the single crystal cutting method shown in the above-mentioned conventional document 2, by slicing a single crystal ingot along its crystal habit line, the warp of the wafer is less likely to occur, but there is a possibility that the wafer cannot be controlled. The amount of bending is the problem point.

In addition, according to the single crystal cutting method shown in the above-mentioned conventional document 3, in order to make the amount of warpage of the wafer sliced by the cutting device into a predetermined amount, the predetermined rotation angle when the ingot is joined and held by the above-mentioned holder is determined. However, it is necessary to combine the columnar semiconductor single crystal ingot to cut the crystal axis of the ingot different from the central axis of the column of the ingot.

Therefore, the rotation angle of the ingot is limited, the setting range of the above-mentioned predetermined rotation angle when the ingot is held by the holder is widely set, and the angle of the crystallographic axis of the ingot to adjust the deviation must be within the range of the predetermined rotation angle. The predetermined rotation angle is set widely, and as a result, there is a problem that the amount of warpage of the wafer may increase.

An object of the present invention is to provide a method for slicing a semiconductor single crystal ingot, which can not only reduce the warpage of the wafer, but also control the warpage of the wafer to a desired amount with high precision.

A first aspect of the present invention is characterized in that a columnar semiconductor single crystal ingot is rotated by a predetermined rotation angle with the crystal axis of the ingot being different from the columnar central axis of the ingot as the center. In the slicing method of a semiconductor single crystal ingot in which the ingot is sliced by a cutting device in this state with bonding and holding, the special feature is that the ingot is determined by the amount of curvature of the wafer sliced by the cutting device to a predetermined amount. The predetermined rotation angle when the holder is engaged and held and the inclination angle of the holder of the cutting device.

According to the slicing method of the first aspect of the present invention, before joining and holding the cylindrical semiconductor single crystal ingot with the holder of the cutting device, first, the ingot is set with the crystal axis of the ingot different from the cylindrical central axis as the center. Then, the ingot is joined and held by the above-mentioned holder in a state in which the ingot is rotated by a predetermined rotation angle around its crystal axis. In this case, since the predetermined rotation angle of the crystal axis as the center and the inclination angle of the holder of the cutting device are determined, the amount of curvature of the wafer sliced by the cutting device is set to a predetermined amount, and the ingot can be sliced with high precision. The amount of warpage of the resulting wafer is a desired amount.

A second aspect of the present invention is the invention according to the first aspect, and is characterized in that the predetermined rotation is determined based on the correlation relationship between the change in the amount of curvature of the wafer with respect to the change in the predetermined rotation angle is obtained in advance through experiments. angle.

According to the slicing method according to the second aspect of the present invention, the correlation relationship between the change in the amount of warpage of the wafer with respect to the change in the predetermined rotation angle is obtained experimentally in advance, and the predetermined rotation angle can be determined based on the correlation relationship, so that higher accuracy can be achieved. Controls the amount of warpage of the wafer after slicing the ingot.

A third aspect of the present invention is based on the first aspect of the invention, characterized in that a predetermined rotation angle of the holder when the ingot is joined and held is determined in order to minimize the amount of warpage of the wafer sliced by the dicing device.

According to the slicing method of the third aspect of the present invention, since the predetermined rotation angle around the crystallographic axis of the ingot is determined, the amount of warpage of the wafer sliced by the cutting device is minimized, and the slicing of the wafer after slicing the ingot can be reduced. amount of bending.

A fourth aspect of the present invention is the invention according to the first aspect, characterized in that a rotation reference portion is further formed in the ingot, and when a vertical line descending from the crystallographic axis of the ingot to the rotation reference portion is used as the reference line, for this reference line The predetermined rotation angle is within any range of 45~55 degrees, 125~135 degrees, 225~235 degrees and 305~315 degrees.

According to the slicing method of the fourth aspect of the present invention, when the vertical line descending from the crystal axis of the ingot to the rotation reference portion is used as the reference line, the predetermined rotation angle with respect to the reference line is set at 45 to 55 degrees, 125 to 135 degrees In any range of 225 to 235 degrees, and 305 to 315 degrees, the amount of warpage of the wafer after cutting the ingot becomes an approximately desired amount.

Next, the form for implementing this invention is demonstrated based on drawing. As shown in FIGS. 1 and 2 , a wire saw device 16 is used to slice and cut the single crystal silicon ingot 13 .

The wire saw device 16 as a cutting device includes first and second main rollers 11 and 12 arranged in the same horizontal plane with their central axes parallel to each other, and first and second main rollers 11 and 12 arranged below the first and second main rollers 11 and 12 A single sub-roller 17 at an intermediate position of the second main rollers 11 and 12, a wire 18 extending around the first and second main rollers 11 and 12 and the single sub-roller 17, and a lifting device 19 for raising and lowering the holder 14 (the first and Fig. 2).

In addition, the outer peripheral surfaces of the first and second main rollers 11 and 12 and the single sub-roller 17 are provided with a predetermined distance in the axial direction of each of the rollers 11, 12 and 17, that is, only the thickness of the sliced wafer is applied to each of the rollers 11. , 12 and 17 are spaced apart in the axial direction to form a plurality of annular grooves (not shown) extending in the circumferential direction.

The wire 18 is a long strip wound around the draw-out drum 21 (FIG. 2), so as to extend from each ring groove on one end side of the first and second main rollers 11 and 12 and the single sub roller 17 to each ring groove on the other end side. The steel wires 18 drawn out from the draw-out drum 21 are sequentially accommodated, the rollers 11, 12, and 17 are slightly inversely triangular in shape and spirally wound and extended, and then wound around the drum 22 (FIG. 2).

The holder 14 has a slicing table 14a joined to the ingot 13 and a work plate 14b holding this slicing table 14a. The slicing table 14a and the ingot 13 are made of the same material, or glass, ceramics, carbon, or resin, but carbon, resin, etc. are often used in consideration of cost and ease of molding. In addition, as a bonding agent, epoxy resin, thermoplastic wax, etc. are used, and the work plate 14b is mainly formed of SUS (stainless steel). Further, the elevating device 19 includes a support member 19a extending in the vertical direction, and a horizontal member 19b which can be mounted up and down to the support member 19a and hold the holder 14 to the lower surface of the front end. Thereby, the ingot 13 joined to the holder 14 is comprised so that the raising/lowering apparatus 19 may raise/lower.

Generally, the crystal orientation of the ingot 13 is somewhat uneven, and the cylindrical center axis of the ingot 13 does not necessarily coincide. Therefore, when the slicing table 14a is joined in the direction of the cylindrical center axis of the ingot 13 and attached to the wire saw device 16 for slicing, the cut surface of the wafer cut out from the ingot 13 does not coincide with the crystal lattice plane. There are uneven characteristics.

As one of the methods for solving this problem, a method of using the variable angle setter 19c is well known.

The angle changer 19c is attached to the lower surface of the horizontal member 19b, and the attachment angle of the holder 14 in the state of being attached to the wire saw device 16 can be adjusted in a plane perpendicular to the wire 18. Specifically, the variable angle setter 19c includes a fixed member 191 and a movable member 192 as shown in FIG. 3 .

The fixing member 191 is attached to the horizontal member 19b.

The lower surface of the fixing member 191 is formed with a concave curved surface, a concave curved surface, and a cylindrical concave curved surface having an arc-shaped cross section in a plane perpendicular to the running direction of the wire 18 .

A movable member 192 is attached to the lower surface of the fixed member 191 . The movable member 192 has a convex curved surface imitating the concave curved surface formed on the lower surface of the fixed member 191. For the fixed member 191, when the movable member 192 is moved, the movable member can be adjusted in the vertical direction within the plane perpendicular to the running direction of the wire 18. 192.

When the movable member 192 is adjusted, the vertical shaft 193 is rotated to change the screwing position of the centrally formed feed screw. Thereby, the movable member 192 moves along the curved surface of the fixed member 191 in the plane perpendicular to the wire 18, and the position in the vertical direction can be adjusted.

According to the variable angle setter 19c, the orientation of the wire 18 can be adjusted so that the crystal orientation of the ingot 13 becomes an appropriate direction within a plane perpendicular to the wire 18.

A method of slicing the single crystal silicon ingot 13 will be described using the wire saw device 16 thus constructed.

First, an extension wire 18 is wound between the first and second main rollers 11 and 12 and a single sub-roller 17 . Thereby, the wire 18 extending horizontally between the first and second main rollers 11 and 12 among the wires 18 moves horizontally in accordance with the rotation of the first and second main rollers 11 and 12 and the single sub-roller 17 .

Next, the work plate 14b for joining the ingot 13 and the slicing table 14a is attached to the variable angle setter 19c provided on the lower surface of the front end of the horizontal member 19b of the lifter 19 by fixing means such as bolting.

Here, the joining method to the slice table 14a of the ingot 13 is demonstrated in detail.

First, the ingot 13 is rotated by a predetermined rotation angle around the cylindrical center axis of the ingot 13 to join. A predetermined rotation angle is determined so that the amount of curvature of the wafer 23 sliced by the wire saw device 16 becomes a predetermined amount.

For this determination, it is preferable to determine the predetermined rotation angle based on the correlation relationship between the change in the amount of curvature of the wafer 23 with respect to the change in the predetermined rotation angle is obtained in advance experimentally. Also, a vertical line descending from the crystallographic axis 13b of the ingot 13 to the orientation flat 13c is used as the reference line 13d, and the predetermined rotation angle θ (FIGS. 5 and 6) with respect to the reference line 13d is preferably set at 45 to Within any range of 55 degrees, 125 to 135 degrees, 225 to 235 degrees, and 305 to 315 degrees.

However, generally, when the ingot 13 is joined to the slicing table 14a, since the joining avoids the orientation flat 13c, the predetermined rotation angle θ with respect to the reference line 13d is preferably set in the range of 45 to 55 degrees or 305 to 315 degrees. Inside.

Here, the predetermined rotation angle θ with respect to the reference line 13d is limited to the above-mentioned range because the wire 18 tends to deviate in the direction of the cleavage surface 13e of the ingot 13, and the amount of warpage of the wafer 23 obtained by slicing the ingot 13 is not limited. increase in size.

However, in the columnar ingot 13, the central axis 13a of the column and the crystal axis 13b are almost not in an ideal state (Fig. 4 (Z axis), Fig. 9A), and the central axis 13a of the column is almost the same as the crystal axis 13a. The actual state in which the axis 13b does not coincide (Fig. 4 (P1-P2), Fig. 9B). Usually, the inclination angle of the cylindrical central axis 13a of the ingot 13 and the crystallographic axis 13b of the ingot 13 is about 3 degrees at the maximum.

On the other hand, for the surface of the sliced wafer 23, the plane perpendicular to the crystal axis 13b of the ingot 13 was obtained (Fig. 9C).

Therefore, when the ingot 13 is rotated by the predetermined rotation angle around the central axis 13a of the column of the ingot 13, and the ingot 13 is joined to the slicing table 14a, the crystallographic axis 13b of the ingot 13 is deviated from the longitudinal direction (FIG. 4). .

For the deviation, the joining direction of the slicing table 14a and the work plate 14b is corrected in the horizontal direction (XZ plane in FIG. 4 ), and the crystal axis 13b of the ingot 13 is joined in the YZ plane in FIG. 4 .

Next, the ingot 13 is moved above the wire 18 extending horizontally between the first and second main rollers 11 and 12 and passing between the vertical lines of the center axes of the first and second main rollers 11 and 12. The crystallographic axis 13b of the ingot 13 and the respective central axes of the first and second main rollers 11 and 12 are made substantially parallel (FIGS. 1 and 2). At this time, the vertical plane including the crystallographic axis 13b of the ingot 13 is made perpendicular to the horizontal extending direction of the wire 18 between the first and second main rollers 11 and 12 (FIG. 9C).

Moreover, according to the variable angle setting device 19c of the fixed holder 14, the fixed angle of the holder 14 is adjusted so that the crystal axis 13b is parallel to the respective central axes of the first and second main rollers 11 and 12.

In other words, the crystallographic axis 13b of the ingot 13 is perpendicular to the plane formed between the wire 18 between the first and second main rollers 11 and 12 and the cutting direction of the ingot 13 of the wire 18 . In this state, the ingot 13 is lowered in the vertical direction, and the ingot 13 is sliced by moving the wire 18 moving in the horizontal direction to the cross-cutting position. Therefore, the warpage amount of the wafer 23 after slicing the ingot 13 can be controlled to a desired amount with high precision.

Here, even if the cleaved surface 13e of the ingot 13 is parallel to the wire mark 13f on the surface of the wafer 23, the amount of warpage of the wafer 23 obtained by slicing the ingot 13 may be different. The reason for this will be described with reference to FIGS. 5 to 8 .

As shown in FIGS. 7A and 8A, even if the cleaved surface 13e of the ingot 13 is parallel to the wire mark 13f on the surface of the ingot 13, the cleaved surface 13e of the ingot 13, as shown in FIG. 7B, is opposite to the crystal axis of the ingot 13. When 13b is inclined, as shown in FIG. 8B, the crystallographic axis 13b of the ingot 13 may be parallel.

Then, when the cleavage surface 13e of the ingot 13 is inclined with respect to the crystallographic axis 13b of the ingot 13 (FIG. 7B), when the ingot 13 is sliced, the wire 18 corresponds to the broken line arrow in the perspective view (a) of FIG. 5 and the 7C The cutting direction indicated by the solid arrow in FIG. 5 easily deviates from the direction indicated by the solid arrow in the perspective view (a) of FIG. 5 and the broken line arrow in FIG.

On the other hand, when the cleavage surface 13e of the ingot 13 is parallel to the crystallographic axis 13b of the ingot 13 (FIG. 8B), when the ingot 13 is sliced, the wire 18 corresponds to the broken line arrow in the perspective view (a) of FIG. 6 and The cutting direction indicated by the solid line arrow in Fig. 8C is not easily deviated, and the cutting direction advances straightly.

As a result, even if the cleaved surface 13e of the ingot 13 is parallel to the wire mark 13f on the surface of the ingot 13 (FIG. 7A), the cleaved surface 13e of the ingot 13 is inclined to the crystallographic axis 13b of the ingot 13 as shown in FIG. 7B At this time, the wafer 23 obtained by slicing the ingot 13 is turned over as shown in the side view (b) of FIG. 5 .

On the other hand, even if the cleaved surface 13e of the ingot 13 is parallel to the wire mark 13f on the surface of the ingot 13 (FIG. 8A), the cleaved surface 13e of the ingot 13, as shown in FIG. 8B, is opposite to the crystal axis of the ingot 13 When 13b is parallel, the wafer 23 obtained by slicing the ingot 13 is not inverted as shown in the side view (b) of FIG. 6 . Moreover, as shown in FIG. 8B, even if the cleavage surface 13e of the ingot 13 is not parallel to the crystallographic axis 13b of the ingot 13, the wafer 23 obtained by slicing is not easily inverted if the angle is close to parallel.

On the other hand, in order to minimize the amount of warpage of the wafer 23 obtained by slicing the ingot 13 by the wire saw device 16 , a predetermined rotation angle about the crystallographic axis 13 b of the ingot 13 may be determined. For example, when the crystallographic axis 13b of the ingot 13 is <111>, a vertical line descending from the crystallographic axis 13b to the orientation plane 13c is used as the reference line 13d, and the predetermined rotation angle θ to this reference line 13d (the fifth and sixth ) in the range of 45 to 55 degrees, the amount of warpage of the wafer 23 after slicing the ingot 13 can be reduced.

In the above-described embodiment, a single crystal silicon ingot is used as the semiconductor single crystal ingot, but may be a silicon carbide (SiC) single crystal ingot, a gallium arsenide (GaAs) single crystal ingot, or a sapphire single crystal ingot. Wait.

In the above-mentioned embodiment, the vertical line descending from the crystallographic axis of the ingot to the orientation plane is used as the reference line to determine a predetermined rotation angle centered on the crystallographic axis of the ingot. The vertical line may be used as a reference line, and a predetermined rotation angle about the crystal axis of the ingot may be determined.

In addition, if there is a rotation reference part instead of the orientation plane or the notch, a vertical line descending from the crystal axis of the ingot toward the rotation reference part can be used as the reference line, and a predetermined rotation angle centered on the crystal axis of the ingot may be determined. . [Example]

Next, the examples of the present invention will be described in detail along with the comparative examples. <Example 1>

As shown in Figs. 1 and 2, a cylindrical monocrystalline silicon ingot 13 having a diameter of 150 mm and a crystal axis of <111> is prepared, and the cylindrical central axis 13a of the ingot 13 is rotated by a predetermined rotation angle as the center. , the ingot 13 and the slicing table 14a are joined. In addition, the slicing table 14a and the work plate 14b are corrected in the horizontal direction (XZ plane in FIG. 4 ), and the crystal axis of the ingot 13 is joined in the YZ plane in FIG. 4 . In addition, the holder 14 for joining the ingot 13 is attached and fixed to the variable angle setter 19c, and the variable angle setter 19c is used to adjust the crystal axis 13b to be parallel to the respective center axes of the first and second main rollers 11 and 12. The fixed angle of the holder 14.

The crystallographic axis 13b of the ingot 13 is detected based on the angle of X-rays reflected from the crystallographic surface after irradiation. Also, a predetermined rotation angle when joining the ingot 13 to the holder 14 is determined.

When the above-mentioned predetermined rotation angle is the reference line 13d, the vertical line descending from the crystal axis 13b of the ingot 13 to the orientation plane 13c is used as the reference line 13d to form the rotation angle θ (FIGS. 5 and 6).

Specifically, above the wire 18 extending horizontally between the first and second main rollers 11 and 12 of the wire saw device 16 is between the vertical lines passing through the respective central axes of the first and second main rollers 11 and 12 , move the ingot 13 so that the crystallographic axis 13b of the ingot 13 is substantially parallel to the respective central axes of the first and second main rollers 11 and 12 (FIGS. 1 and 2). At this time, the vertical plane including the crystallographic axis 13b of the ingot 13 is made perpendicular to the extending direction of the wire 18 between the first and second main rollers 11 and 12 (FIG. 9C).

Then, the holder 14 for joining the ingot 13 is attached and fixed to the variable angle setter 19c, and the fixed angle of the holder 14 is adjusted by the variable angle setter 19c so that the crystal axis 13b and the first and second main rollers 11, The central axes of 12 are parallel.

The ingot 13 is lowered in the vertical direction, and the wire 18 moving in the horizontal direction is moved to a position of transverse cutting, and the ingot 13 is sliced to form a wafer 23 . The predetermined rotation angle θ is adjusted to 45 to 55 degrees, and the ingot 13 is sliced into wafers 23 in the same manner as described above. These wafers 23 serve as Example 1. <Comparative Example 1>

The crystal axis of the ingot, which is different from the cylindrical central axis of the ingot, is used as the center, and is held by the holder while being rotated only by an arbitrary rotation angle, and the holder 14 that joins the ingot 13 is attached and fixed to the variable angle setter 19c After that, except that the fixed angle of the holder 14 of the variable angle setting device 19c was not adjusted, the ingot was sliced into a wafer in the same manner as in the first embodiment. These wafers serve as Comparative Example 1. <Test 1 and evaluation>

The amount of warpage of the wafers of Example 1 and Comparative Example 1 was measured. The amount of curvature of the wafer, on the backside of the wafer, from the outer peripheral edge of the wafer to the inner side of 3 mm, is assumed to pass through the crystal axis of the wafer as the center at 3 points determined at a distance of 120 degrees. Among the measured warpage sizes of the wafer, the maximum value is obtained. The results are shown in FIG. 10 .

According to FIG. 10, it is clear that in Comparative Example 1, although the amount of curvature of the wafer within the predetermined rotation angle range is small, the amount of curvature of the wafer outside the range of the predetermined rotation angle is large. In Example 1, by adjusting When the rotation angle θ is increased to 45 to 55 degrees, the amount of warpage of the wafer is all reduced.

11, 12‧‧‧1st and 2nd main rollers 13‧‧‧Ingot 13a‧‧‧Central axis 13b‧‧‧Crystalline axis 13c‧‧‧Orientation plane 13d‧‧‧Baseline 13e‧‧‧Split face 13f‧‧‧Wire mark 14‧‧‧Retainer 14a‧‧‧Slicing stage 14b‧‧‧Working board 16‧‧‧Cut-off device 17‧‧‧Sub roller 18‧‧‧Wire 19‧‧‧Lifting device 191‧‧‧Fixed components 192‧‧‧Moveable components 193‧‧‧Vertical axis 19a‧‧‧Support Components 19b‧‧‧Horizontal member 19c‧‧‧Variable angle setting device 21‧‧‧Extraction cylinder 22‧‧‧Reel 23‧‧‧Wafer

[FIG. 1] is a front view of the main part showing a state in which a single crystal silicon ingot is sliced with the wire of a wire saw device using the slicing method according to the first embodiment of the present invention; The perspective view of the main part of the state where the steel wire is to be sliced into the ingot; [Fig. 3] is a cross-sectional view showing the plane perpendicular to the wire running direction of the gonio setting device structure; [Fig. 4] is the ingot. A schematic perspective view of the relationship with the holder; [Fig. 5] is a perspective view of the wafer showing the mechanism by which a cleavage plane appears in the cutting direction when an ingot is cut by a wire, and the wire deviates in the direction of the cleavage plane (a) and The side view (b) of the wafer after cutting with a large curvature; [Fig. 6] shows that in the cutting of the ingot by the steel wire, no cleavage surface appears in the cutting direction, and the steel wire is cut toward the Wafer perspective view (a) of the mechanism in which the breaking direction is straight forward, and a side view of the wafer after cutting without bending (b); [Fig. 7A] shows that the split surface of the ingot is parallel to the wire mark on the surface of the ingot. The front view of the ingot; [Fig. 7B] is a longitudinal sectional view of the ingot in which the cleavage face of the ingot is inclined to the crystallographic axis of the ingot; [Fig. 7C] is a cast showing that the steel wire is deviated in the direction of the cleave plane. Longitudinal sectional view of the ingot; [Fig. 8A] is a front view of the ingot with the cleaved surface of the ingot parallel to the wire mark on the surface of the ingot; [Fig. 8B] is the crystallization of the cleaved face of the ingot facing the ingot A longitudinal sectional view of an ingot in a state where the axes are parallel; [Fig. 8C] is a longitudinal sectional view of an ingot with the wire going straight in the cutting direction; [Fig. 9A] shows the crystallographic axis and the cylindrical center axis of the ingot Consistent, the composition diagram of the state in which the central axis of the cylinder and the crystallographic axis are extended and arranged in a right-angle direction; [Fig. 9B] is a composition diagram of the ingot in a state where the central axis of the cylindrical ingot and the crystallographic axis of the ingot are inconsistent; [Fig. 9C] ] is a diagram showing the state of the crystal axis that does not coincide with the cylindrical central axis of the ingot, and the steel wire is extended and arranged in a right-angle direction; and [Fig. 10] is a diagram showing that the rotation angles of the ingots of Example 1 and Comparative Example 1 were changed, respectively. Graph of the change in the amount of warpage of the wafer.

11, 12‧‧‧1st and 2nd main rollers

13‧‧‧Ingot

14‧‧‧Retainer

14a‧‧‧Slicing stage

14b‧‧‧Working board

16‧‧‧Cut-off device

17‧‧‧Sub roller

18‧‧‧Wire

19‧‧‧Lifting device

19a‧‧‧Support Components

19b‧‧‧Horizontal member

19c‧‧‧Variable angle setting device

Claims (4)

A method for slicing a semiconductor single crystal ingot, wherein a cylindrical semiconductor single crystal ingot is rotated only by a predetermined rotation angle with the crystal axis of the ingot being different from the cylindrical central axis of the ingot as the center, The holder is joined and held by a holder having a slicing table joined to the ingot and a work plate holding the slicing table. In this state, the above-mentioned slicing table is cut by a cutting device having a plurality of main rollers and a wire wound around the rollers and extending. In the method for slicing a semiconductor single crystal ingot sliced from an ingot, the predetermined rotation when the ingot is joined and held by the holder is determined so that the amount of curvature of the wafer sliced by the cutting device becomes a predetermined amount. angle, and the crystallographic axis for joining the slicing table and the work plate into the ingot is determined so that the crystallographic axis and the central axis of the main roller are parallel to the vertical plane including the central axis of the work plate. The angle of inclination of the holder of the above-mentioned cutting device; the angle of inclination of the holder is adjusted by a variable-angle setting device, and the variable-angle setting device has a fixing member whose lower surface forms a concave curved surface, and has a convex curved surface whose upper surface imitates the above-mentioned concave curved surface. A movable member supporting the above-mentioned holder. The method for slicing a semiconductor single crystal ingot as set forth in claim 1, wherein a correlation relationship between changes in the amount of curvature of the wafer with respect to changes in the predetermined rotation angle is obtained in advance through experiments, and then based on the correlation The relationship determines the above-mentioned predetermined rotation angle. The method for slicing a semiconductor single crystal ingot according to claim 1, wherein the holder joint is determined in order to minimize the amount of warpage of the wafer sliced by the cutting device. The above-mentioned predetermined rotation angle at the time of the above-mentioned ingot is maintained. The method for slicing a semiconductor single crystal ingot according to claim 1, wherein a rotation reference portion is formed in the ingot, and a vertical line descending from the crystal axis of the ingot to the rotation reference portion serves as the reference line When the above-mentioned predetermined rotation angle with respect to this reference line is within any of the ranges of 45 to 55 degrees, 125 to 135 degrees, 225 to 235 degrees, and 305 to 315 degrees.

Images