JP2014216424A - Method of manufacturing wafer, and notch processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wafer of crystal, having a crystal structure in which the same crystal plane exists at a point symmetrical position with reference to the center position, the method being capable of reducing the polishing amount when planarizing by providing a mark indicating the direction of a desired crystal plane corresponding to a surface to be mirror polished selected after slicing the wafer.SOLUTION: In a method of manufacturing a wafer by slicing an ingot of a crystal having a crystal structure in which the same crystal orientation plane is arranged point symmetrically, and then mirror polishing one principal surface of the wafer, two temporary marks indicating the direction of crystal orientation plane, respectively, are formed on the side faces of the ingot before being sliced. When mirror polishing one principal surface of the wafer, orientation of the wafer is aligned using the temporary mark indicating the direction of a polished surface, i.e., the convex surface, of the wafer.

Description

  The present invention relates to a wafer manufacturing method and a notch processing apparatus.

  Conventionally, various wafers are used for manufacturing various semiconductor devices and the like.

  When processing a wafer in a manufacturing process of a semiconductor device or the like, the position of the crystal plane of the wafer and the crystal orientation may become a problem depending on the material of the wafer and its use.

  Here, FIG. 1A shows a schematic diagram of a crystal structure in which a specific crystal orientation plane is in a point-symmetrical position. In the schematic diagram of this point-symmetric crystal structure, when the upper surface of the crystal is 12A and the lower surface is 12B, the same crystal orientation planes 11A and 11B at the point-symmetrical position and other identical crystal orientations at the point-symmetrical position There are faces 13A and 13B.

  Here, in FIG. 1A, when the top surface 12A and the bottom surface 12B of the crystal are replaced with 12A as the bottom surface and 12B as the top surface, that is, when rotated 180 ° in the vertical direction (the direction of the arrow X in FIG. 1A). Shown in FIG. 1B. In this case, 12A and 12B are interchanged, but 13B is placed at the position of 11A, 11A is placed at the position of 13B, 11B is placed at the position of 11B, and 11B is placed at the place of 13A, and the arrangement of the crystal orientation planes is changed. .

  In order to exchange 12A and 12B so that the orientation of the crystal orientation plane does not change, first, it is rotated 180 ° in the vertical direction (the direction of arrow X in FIG. 1A) to the state of FIG. 1B, and then the horizontal direction (in FIG. 1A). In the direction of arrow Y). By performing such an operation, 12A and 12B can be interchanged so that the orientation of the crystal orientation plane does not change as shown in FIG. 1C.

  As described above, when the crystal orientation of the wafer or the position of the crystal plane is a problem, in the wafer 20 shown in FIG. 2 made of the crystal having the point-symmetric crystal structure as described above, the axis X of the wafer 20 is the crystal structure 10. When the direction of each surface of the crystal structure 10 and the direction of the crystal plane included in the wafer coincide with each other, as in the case of the crystal structure, depending on which of the main surfaces 22A and 22B is selected, 21A , 21B indicates a different characteristic direction.

  For this reason, when the crystal orientation or crystal plane is a problem, an orientation flat or notch may be provided as a mark indicating the desired crystal plane or crystal orientation in order to indicate the crystal plane or crystal orientation of the wafer. is there.

  When orientation flats and notches are formed after processing into a wafer shape, processing is performed after the crystal plane and crystal orientation are detected for the entire peripheral surface of each wafer, resulting in poor processing efficiency. Furthermore, chipping and scratches are likely to occur. For this reason, the process which forms orientation flat etc. in the step of the cylindrical block (ingot) before a slice is performed (for example, patent document 1).

  And a predetermined process will be performed with respect to the wafer sliced based on the orientation flat etc. attached in the step of the cylindrical block. That is, the surface (direction) on which the predetermined processing is performed is determined before the wafer is sliced.

  Incidentally, a wafer is generally manufactured by slicing an ingot. However, the sliced wafer may be warped, that is, a convex surface and a concave surface may occur. In particular, the degree of unevenness in one ingot is not necessarily small, and the direction thereof may not be aligned with the direction of the ingot.

  However, in recent years, the demand for wafer flatness in product specifications has become stricter. When the wafer is warped during cutting as described above, it is necessary to flatten it by processing to increase the flatness.

  When flattening a wafer having warpage, when processing one surface as a mirror surface and the other surface as a matte surface, when producing a wafer of a so-called single-side polished product, the convex surface side of the wafer having warpage is formed as described above. When polishing so as to have a mirror surface (surface), warpage can be reduced even with a small polishing amount.

  However, when the polishing surface is selected according to the warping direction of the wafer in the wafer having the point-symmetric crystal structure as described above, the surface to be polished is the same as the conventional method of forming the orientation flat. In some cases, the orientation flat or the like indicates a direction different from the necessary crystal orientation, so that the surface to be mirror-polished after slicing cannot be arbitrarily selected. As described above, when the direction of warping is not uniform when one ingot is cut, the convex surface side of the wafer cannot be always mirror-polished.

  For this reason, when the crystal wafer having the crystal structure as described above is flattened, the above polishing method that reduces the polishing amount cannot be employed. Therefore, in order to manufacture a wafer having a desired flatness, the wafer can be flattened even if the concave surface is polished. For example, when the wafer is sliced from an ingot, the cutting thickness is increased to increase the polishing amount. The method of correcting by this was taken.

JP 2004-250248 A

  However, when the wafer can be made flat even if the concave surface is polished as described above, the wafer is sliced thickly from the ingot, so that the number of wafers that can be collected from one ingot is reduced. Further, since the wafer is thick and the amount of polishing is large, and polishing takes time, productivity is lowered, and further, there is a problem that the life of the abrasive used for polishing is shortened.

  Therefore, in view of the problems of the above-described conventional technology, the present invention provides a method for manufacturing a wafer having a crystal structure in which the same crystal orientation planes are arranged at point symmetry positions. An object of the present invention is to provide a method for manufacturing a wafer that can be reduced.

In order to solve the above problems, the present invention is a wafer manufacturing method in which after slicing a crystal ingot having a crystal structure in which the same crystal orientation planes are arranged point-symmetrically, one side of the main surface of the wafer is mirror-polished. ,
Two temporary marks indicating the respective directions of the crystal orientation planes are formed on the side surface of the ingot before slicing,
Provided is a method for producing a wafer, characterized in that when one surface of the main surface of a wafer is mirror-polished, the convex surface of the wafer is used as a polishing surface and the orientation of the wafer is adjusted using a temporary mark indicating the direction of the polishing surface.

  According to the present invention, in a method for manufacturing a wafer having a crystal structure in which the same crystal orientation plane is arranged at a point-symmetrical position, a method for manufacturing a wafer capable of reducing the amount of polishing when the wafer is sliced and planarized is provided. be able to.

Illustration of point-symmetric crystal structure Diagram of a point-symmetric crystal structure rotated 180 ° vertically Diagram of point-symmetric crystal structure rotated 180 ° vertically and horizontally Illustration of the relationship between crystal structure and wafer Explanatory drawing of the ingot which formed the temporary mark in 1st Embodiment Explanatory drawing of the process which chamfers the edge part of the wafer in 1st Embodiment, and erases a temporary mark. Explanatory drawing of the structural example of the notch processing apparatus in 2nd Embodiment. Explanatory drawing of the method of detecting a temporary mark with two contact-type sensors arrange | positioned adjacently in 2nd Embodiment. Explanatory drawing of the notch formation method by the notch processing apparatus in 2nd Embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
[First Embodiment]
In the present embodiment, a configuration example of the wafer manufacturing method of the present invention will be described.

  The wafer manufacturing method according to the present embodiment is a wafer manufacturing method in which, after slicing a crystal ingot having a crystal structure in which the same crystal orientation planes are arranged in point symmetry (position), one side of the main surface of the wafer is mirror-polished. About. Then, two temporary marks indicating the respective directions of the crystal orientation plane are formed on the side surface of the ingot before slicing, and when one side of the main surface of the wafer is mirror-polished, the convex surface of the wafer is used as the polishing surface, The orientation of the wafer can be adjusted using a temporary mark indicating the direction.

  As shown in FIG. 2, the crystal structure (crystal lattice) of the wafer crystal manufactured in this embodiment is on the center O of the crystal structure 10 (on the central axis X of the crystal structure 10 and from the upper surface 12A and the lower surface 12B). It has the same crystal orientation planes 11A and 11B at the point symmetry position (or similarity position) with respect to the distance (point at a distance) as a reference (symmetry point or similarity point).

  For this reason, in the crystal structure 10 as described above, the crystal orientation planes 11A and 11B are viewed from the upper surface 12A (or the lower surface 12B), as viewed from the 14A side and the lower surface 12B indicated by the block arrows in the drawing. The direction is equivalent to the 14B side indicated by the block arrow. Similarly, the 14B side when viewed from the upper surface 12A is equivalent to the 14A side when viewed from the lower surface side 12B.

  In FIG. 2, when the crystal wafer 20 having such a crystal structure 10 and the crystal structure 10 have the same axis X direction and the crystal orientation plane directions, The direction corresponding to the crystal orientation planes 14A and 14B in the crystal structure 10 corresponds to the direction of 21A and 21B in the wafer 20. In the wafer 20, for example, if a mark is to be formed in a direction equivalent to the direction of 14A viewed from the upper surface side 11A in the crystal structure 10, the main surface 22A of the wafer 20 is referred to the 21A side (for example, the 23A portion), When the main surface 22B is used as a reference, a mark is formed on the 21B side (for example, the 23B portion).

  When it has such a crystal structure and the above-mentioned directions (14A and 14B) need to be identified on the wafer, 23A or 23B can be identified according to the reference plane. It is necessary to form a mark on any one of the desired portions.

  In the wafer manufacturing method of the present embodiment, when mirror polishing is performed on a wafer having such a crystal structure, the convex surface of the wafer is used as a polishing surface, and a temporary mark corresponding to the polishing surface or the position of the wafer is used. Can be combined. For this reason, it is possible to reduce the amount of polishing when removing the warpage of the wafer to obtain a flat shape. Since the amount of polishing can be reduced in this way, the number of wafers obtained from one ingot can be increased, and further, the time required for polishing can be reduced and the life of the polishing agent can be made longer than before. Can also be long.

  1 and 2, an example in which the crystal orientation surface 11A or 11B in the crystal structure is adjacent to the upper surface 12A or the lower surface 12B is described. However, the crystal orientation surface is the center of the crystal structure 10. It suffices if it is in a point-symmetrical position with respect to O, and is not limited to such a form.

  Further, the material having the crystal plane arrangement shown in FIG. 1 includes, for example, sapphire, but is not limited thereto, and the manufacturing method of the present embodiment is similarly applied to a wafer having the above crystal structure. be able to.

  The wafer manufacturing method of this embodiment will be described below.

  First, a process of forming two temporary marks indicating the directions of the crystal orientation planes on the side surface of the ingot before slicing will be described.

  The temporary mark is formed before slicing (cutting) the wafer, that is, in an ingot (cylindrical block) state. This is because, before slicing the wafer, the positions (directions) corresponding to the crystal orientation planes 11A and 11B are detected and uniformly formed on the side surfaces of the ingot, whereby temporary marks can be formed efficiently. is there.

  In the present embodiment, the temporary marks are positions (directions) respectively corresponding to the directions (14A and 14B) of the crystal orientation surfaces 11A and 11B of the crystal structure 10 shown in FIG. 2, and are formed on the side portions of the ingot. The This is because when the wafer 20 shown in FIG. 2 is used, even if any of the main surfaces 22A and 22B is selected as a surface to be mirror-polished, the orientation of the wafer can be adjusted using temporary marks. It is to make it.

  A configuration example when the temporary mark is formed on the ingot will be described with reference to FIG. 3A shows a perspective view of the ingot with provisional marks, and FIG. 3B shows a view seen from the direction of arrow A in FIG. 3A.

  As shown in FIGS. 3 (A) and 3 (B), a temporary mark that is a side surface of the ingot 30 and is in a position corresponding to the direction of the crystal orientation plane to which the temporary mark is to be applied, and is parallel to the central axis of the ingot 31 and 32 are formed. In this case, the temporary marks 31 and 32 are formed at positions facing the ingot.

  In addition, in FIG. 3, although the example which provided orientation flat was shown as a temporary mark, the form of a temporary mark is not specifically limited, The process of forming a mirror surface polishing process, for example, the postmark mentioned later, for example What is necessary is just to be able to detect the position when performing. For example, it can be formed by orientation flat, a method of forming a notch or the like, or writing a mark with a laser or the like. However, when the final product of the wafer is used, it is preferable that the temporary mark does not remain on the wafer. Therefore, it is preferable that the wafer can be erased without being damaged by polishing or chemical treatment.

  The size of the temporary mark is not particularly limited. However, if it is too large, the usable area of the wafer is reduced when it is removed by polishing or the like as described above. For example, when the temporary mark is used in a process of forming the main mark, which will be described later, it is preferable that the minimum size is detected by a detector that detects the position of the temporary mark.

  In the temporary mark forming step, it is preferable that the portion provided with each temporary mark can be identified as the direction of 21A or 21B in FIG. Specifically, for example, the shapes and / or sizes of the two temporary marks formed in this step are preferably different. That is, in FIG. 3, it is preferable that the shape and / or size of one temporary mark 31 and the other temporary mark 32 formed at opposite positions are different. Here, it is conceivable that the shapes are different, for example, that one is an orientation flat and the other is a notch, or that notches are formed on both sides and the shapes are different. When forming temporary marks in this way, it is possible to more reliably prevent the directions indicated by the temporary marks from being confused by providing temporary marks having different sizes and / or shapes. For this reason, for example, in the case of imparting (forming) a mark to be described later, it is possible to omit the step of detecting the crystal face of the side surface portion, and it is possible to further increase productivity.

  After forming the temporary mark, a cutting step of slicing the ingot to form a wafer can be performed. Regarding the cutting step, an optimum slicing (cutting) method can be selected according to the material of the wafer. For example, an ingot can be sliced (cut) using a wire saw.

  In addition, when performing the process of forming the main mark, which will be described later, the front surface 22A and the back surface 22B in FIG. Is preferably recognized. Specifically, for example, when the main cutting process is performed, a method in which a display indicating the direction of the front surface or the back surface is provided in advance on a support member that supports the ingot. In this way, by configuring so that the front surface and the back surface of the formed wafer can be identified, it is possible to easily specify the position where the main mark is formed when forming the main mark as will be described later. .

  Next, a step of selecting a surface to be mirror-polished out of the main surface of the wafer can be performed.

  As described above, when producing a wafer whose one surface is a mirror surface and the other surface is a matte surface, that is, a so-called single-side polished product, the convex surface side of the wafer having warpage is made a mirror surface (surface). When the polishing is performed, the wafer can be flattened (warping is removed or reduced) regardless of a small amount of polishing.

  According to such a wafer flattening method, the amount of polishing can be reduced as compared with the conventional method in which the thickness of the wafer is sliced thick and flattened by polishing. Therefore, the polishing time can be shortened, and the life of the abrasive used for polishing can be extended. In addition, since the thickness of the wafer when slicing the wafer from the ingot can be reduced, more wafers can be obtained from one ingot.

  For this reason, in this process, when the wafer obtained in the cutting process has a warp, it is preferable to select the convex side as a surface to be mirror polished. When a wafer having no warpage is obtained, any surface may be selected as a surface to be mirror polished.

  The convex surface can be selected based on the measurement result obtained by measuring the shape of the wafer using a contact-type or non-contact-type shape measuring device for the wafer obtained by the cutting process.

  The selected surface only needs to be recognized in a later step, and it is not necessary to perform processing or the like. However, for example, a mark or the like can be written on the selected surface or the back surface thereof with a laser or the like.

  As described above, in the step of selecting the surface to be mirror-polished out of the main surfaces of the wafer, for example, the convex surface of the wafer can be selected as the polishing surface for mirror polishing. Then, by using a temporary mark indicating the direction of the selected polishing surface, that is, a temporary mark corresponding to the selected polishing surface, the orientation of the wafer can be adjusted when mirror polishing of the main surface of the wafer is performed.

  In particular, prior to mirror polishing of the main surface of the wafer, it is preferable to perform a step of forming the main mark on one of the temporary marks based on the selected mirror-polished polishing surface.

  In this step, the main mark is formed at the position of the temporary mark indicating the direction of the polished surface. That is, it is a step of forming the main mark on one of the two temporary marks based on the polished surface. By forming the main mark as described above, the orientation of the wafer can be adjusted using the main mark in a mirror polishing process or the like.

  In the crystal structure 10 shown in FIG. 2, the case where the main mark is formed in the direction equivalent to the 14A side viewed from the main surface 12A will be described as an example. In the step of selecting the surface to be mirror-polished, when the main surface 22A of the wafer 20 is selected as the polishing surface to be mirror-polished, the main mark is formed on the 21A side. Further, when the main surface 22B of the wafer 20 is selected as a polishing surface for performing mirror polishing, a main mark is formed on the 21B side.

  Here, the case where the main mark is formed in the equivalent direction to the 14A side as viewed from the upper surface 12A in the crystal structure 10 has been described, but the present invention is not limited to this form, and 14B as viewed from the upper surface 12A. A configuration may be adopted in which the main mark is formed in a direction equivalent to the side. In this case, the main mark is formed in the direction opposite to the above description.

  In this step, if the direction of each temporary mark formed in the step of forming the temporary mark as described above, the direction of each temporary mark formed in the cutting step, and the direction of each front surface (back surface) can be identified, the direction of each surface, temporary mark Then, the main mark can be formed based on the selected surface. In this way, each step is performed so that it can be determined which side of the temporary mark provided at two places is the 21A side or the 21B side in FIG. 2. When the operation is performed so as to be able to be identified, it is not necessary to detect the crystal plane on the side surface of the portion where the temporary mark is formed. In this case, based on whether the surface selected in the step of selecting the surface to be mirror-polished is 22A or 22B, the main mark can be easily given to the desired side.

  If the direction of each surface cannot be identified, the crystal plane can be detected for the side surface of the portion where the temporary mark is formed, and the main mark can be formed on a predetermined side based on the detection result. For this reason, since the detection range of the crystal face of the side part performed for every wafer is limited, the fall of productivity can be controlled.

  The form and size of the mark are not particularly limited, and can be arbitrarily selected according to the user's request. For example, the main mark can be formed by forming an orientation flat, a notch, or writing a mark with a laser or the like. However, when processing such as polishing or chamfering is further performed on the wafer after this step, it is preferable to select a wafer that does not lose its main mark during the processing. For this reason, it is more preferable that the mark is an orientation flat or a notch. Even when an orientation flat or notch is formed, it is preferable that the size or shape does not disappear by processing performed before being supplied to the user.

  And in the manufacturing method of the wafer of this embodiment, mirror polishing can be performed about one main surface selected among the main surfaces of a wafer as mentioned above. At this time, as described above, the orientation of the wafer can be adjusted using the temporary mark indicating the direction of the selected polished surface. When the main mark is formed as described above, the orientation of the wafer can be adjusted using the main mark.

  The method of mirror polishing the wafer is not particularly limited, and can be performed using, for example, a single-side polishing apparatus.

  The wafer manufacturing method of the present embodiment has been described above. However, in the wafer manufacturing method of the present embodiment, an arbitrary process can be further added.

  For example, it is preferable to have a step of erasing temporary marks formed on the wafer. Specifically, it can be a step of chamfering the end surface portion of the wafer and removing the temporary mark.

  For example, as shown in FIG. 4, orientation flats 41 and 42 are formed as temporary marks on both ends thereof, and a new orientation flat 43 is formed on the orientation flat 42 side of the temporary marks as main marks. A case will be described as an example. In this case, the orientation flat 43 as the temporary mark disappears by forming the orientation flat 43 as the main mark, but the other orientation flat 41 remains. For this reason, by chamfering the end surface portion of the wafer to the line indicated by the dotted line 44 in the figure, the orientation flat 41 of the temporary mark can be erased while leaving the orientation flat 43 of the main mark.

  At this time, if the orientation flat or notch of the temporary mark is large, a large area must be removed in the chamfering process. For this reason, as described above, the size of the temporary mark is preferably set to the minimum size that can be detected by the detection device, and the amount removed in the chamfering process is preferably reduced.

  The timing for performing the step of removing (removing) the temporary mark is not particularly limited, and can be performed at an arbitrary timing after the temporary mark is no longer necessary. For example, when the main mark is formed, it can be performed after the step of forming the main mark is performed. Further, when the temporary mark is used only as a mark when the main surface of the wafer is mirror-polished, a step of removing the temporary mark after the mirror-polishing can be performed.

  In the final product, even if the temporary mark remains, there is no problem, or even if it is preferable to remove the temporary mark, this step is performed when the temporary mark disappears in other processing steps. You can not.

  Further, in the wafer manufacturing method of the present embodiment, in addition to the above steps, an end surface polishing step for polishing the end surface portion of the wafer so that the surface of the wafer has desired physical properties, and the wafer is annealed and flattened (warpage). And the like) can be added. Furthermore, depending on the case, the surface on the side opposite to the surface subjected to the mirror polishing can be made to have a desired textured surface by sandblasting or the like.

According to the wafer manufacturing method of the present embodiment described above, when manufacturing a wafer having a crystal structure in which the same crystal orientation planes are arranged at point-symmetric positions, the amount of polishing when flattening after slicing the wafer is reduced. Can be reduced and productivity can be improved.
[Second Embodiment]
In the present embodiment, a notch processing apparatus that can be preferably used when forming the main mark in the wafer manufacturing method described in the first embodiment will be described.

The notch processing apparatus of this embodiment is a notch processing apparatus used when forming the main mark,
Wafer support means for supporting the wafer;
Temporary mark detection means for detecting the position of one temporary mark formed on the wafer;
A notch processing means disposed at a position opposite to the temporary mark detection means, and forming a notch at the other temporary mark position and / or chamfering along the shape of the notch,
The notch processing means includes a disk-shaped processing grindstone,
The disk-shaped processing grindstone is arranged so that the rotation direction of the disk-shaped processing grindstone and the surface of the wafer supported on the wafer support means are orthogonal to each other.

  FIG. 5 shows a configuration example of the notch processing apparatus of the present embodiment. FIG. 5 shows a top view of the notch processing apparatus of the present embodiment.

  As shown in FIG. 5, the notch processing apparatus 50 includes a wafer support unit 52 that holds the wafer 51, a temporary mark detection unit 53 that detects the position of one temporary mark formed on the wafer 51, And / or notching means 54 for chamfering along the shape of the notch.

  The wafer support means 52 is preferably a means that supports the wafer 51 on its surface and can be fixed so that the wafer does not move when the notch is formed. The wafer support means 52 is preferably constituted by, for example, a vacuum chuck or an electrostatic chuck. In addition, since the notch is formed by applying the processing grindstone of the notch processing means 54 to the wafer 51 as will be described later, it is preferable that the wafer support means 52 and the notch processing means 54 are not in contact with each other. For example (in FIG. 5, the wafer support means 54 is shown larger than the diameter of the wafer 51 in order to clarify the configuration), the diameter of the wafer support means 52 is made smaller than the diameter of the wafer 51. The method of configuring is mentioned.

  Further, when detecting the position of the temporary mark of the wafer 51 supported on the wafer support means 52, the wafer 51 is rotated so that the position of the temporary mark can be detected by the temporary mark detection means 53. Is preferred. Therefore, for example, the wafer support means 52 is preferably provided with the wafer support means rotating means 55.

  The temporary mark detecting means 53 may be moved along the peripheral surface of the wafer without rotating the wafer 51 to detect the temporary mark, but in this case, a notch process is performed on the portion facing the detected temporary mark. Both means 54 and means for moving are required.

  Furthermore, it is preferable to provide a means that can displace and adjust the position of the wafer support means 52 such as a stage 56 so that the positions of the wafer 51 and the wafer support means 52 can be adjusted. When the stage 56 is provided, it is preferable to dispose the wafer support means 52 and, in some cases, the wafer support means rotating means 55 on the stage 56. The stage may be capable of displacing the position only in one axial direction, but is preferably an XY stage capable of displacing the position in two axial directions, for example, and may be capable of displacing the position in three axial directions. .

  The temporary mark detecting means 53 is a means for detecting the position of the temporary mark formed in the wafer manufacturing method described in the first embodiment. The temporary mark detection means 53 may be any means that can detect a temporary mark, and can be arbitrarily selected according to the shape, size, and the like of the temporary mark.

  As the temporary mark detection means, for example, a plurality of contact-type displacement sensors arranged adjacent to each other, detection means using a laser, or the like can be used. Among them, since the cost of the sensor is low and the detection can be performed with high accuracy, it is preferable to use a plurality of contact-type displacement sensors arranged adjacent to each other as the temporary mark detection means.

  A plurality of contact-type displacement sensors arranged adjacent to each other are sensors in which a plurality of (for example, two) contact-type displacement sensors are arranged side by side, and are arranged on the peripheral surface of the wafer like an orientation flat or a notch. Temporary marks formed by partly grinding can be detected. Note that the number of contact-type displacement sensors may be plural, and for example, it may be configured by two sensors, but may be three or more.

  The detection method will be described with reference to FIG. FIG. 5 shows a top view of a state in which the wafer 51 is rotated while the two contact sensors 61 and 62 arranged adjacent to the peripheral surface are in contact with each other. In addition, description about a wafer support means etc. is abbreviate | omitted here.

  When the distance between the contact sensors 61 and 62 and the wafer 51 is kept uniform, the difference between the detection values of the two sensors is constant in the portion where the temporary mark on the peripheral surface of the wafer is not provided. Yes. On the other hand, as shown in FIG. 6, one of the contact-type sensors is in contact with a portion of the wafer 51 where the orientation flat 41, which is a temporary mark, is provided, and the other is not provided with the temporary mark. When touching the part, the difference between the detection values of both sensors changes. For this reason, it is possible to discriminate between the portion where the temporary mark is provided and the other portion, and the position of the temporary mark can be detected by the two contact-type displacement sensors arranged adjacent to each other.

  In this way, when a plurality of contact type displacement sensors arranged adjacent to each other are used as sensors and the temporary mark is the orientation flat, the length of the chord of the orientation flat is 4 mm so that the temporary mark can be accurately detected. The above is preferable. In particular, the length of the chord of the orientation flat is more preferably 6 mm or more and 8 mm or less in order to increase detection accuracy and suppress reduction in the area of the wafer.

  Here, the length of the string of the orientation flat means L in FIG. In addition, when the orientation flat which is a temporary mark is provided in two places, the length of the string may differ as described above, and in that case, it is preferable that each satisfies the above range.

  Here, a method has been described in which an orientation flat is provided as a temporary mark and the temporary mark is detected by two adjacent contact displacement sensors. However, the peripheral surface of the wafer is displaced from the circumference. Anything can be detected and is not limited to such a form. Even if the temporary mark is a notch or the like, it can be detected by the sensor.

  Next, the notch processing means 54 will be described.

  As shown in FIG. 5, the notch processing means 54 includes a disc-shaped processing grindstone 541, and the disc-shaped processing grindstone is supported on the rotation direction of the disc-shaped processing grindstone and on the wafer support means. The wafer surface is arranged so as to be orthogonal to the surface of the wafer. Moreover, the said processing grindstone is comprised so that it may rotate with the rotating spindle (motor) 542 connected to this, for example. The type of the processing grindstone is not particularly limited and can be selected depending on the type of wafer to be processed. For example, a metal bond or resin bond diamond grindstone is preferable. Moreover, it is preferable that the outer periphery (tip shape) of the processing grindstone is truing (tip processing) in accordance with a desired width and angle of the notch groove. With this configuration, when forming a notch, it is possible to form a notch having a desired shape simply by pressing (cutting) a processing grindstone rotated at high speed onto a predetermined location on the wafer.

And as shown in FIG. 5, it is preferable that the notch processing means 54 is equipped with the stage 57 so that the position can be adjusted. Such a stage may be displaced only in one axial direction, or may be displaced in a plurality of axial directions. Since the stage adjusts the position with respect to the wafer 51, for example, when the wafer support means 56 is provided on the XY stage as described above, the stage 57 may be constituted by a Z stage.
Further, it is preferable to provide a cutting fluid supply means 58 for supplying a cutting fluid for cooling the polished surface when the wafer 51 is polished.

  A configuration example when forming the notch and / or chamfering the notch will be described with reference to FIG. FIG. 7 is an enlarged view of the wafer 51 and the disk-shaped processing grindstone 541 of the notch processing means 54 when the notch is formed or chamfered. In addition, description is abbreviate | omitted about the surrounding member.

  As shown in FIG. 7, the surface of the wafer 51 and the processing grindstone 541 are arranged so as to be orthogonal to each other, and the wafer contact is made while the processing grindstone 541 rotates in either direction indicated by an arrow A or B in the figure. By doing so, notches can be formed and / or chamfered.

  The notch can be formed by bringing the rotated processing grindstone 541 into contact with the region of the wafer 51 where the notch is to be formed. The chamfering of the notch can be performed by moving the notching 71 while moving the processing grindstone 541 along the surface of the notch 71 formed.

  As described above, the method of providing the notch in the desired temporary mark of the two temporary marks is not particularly limited, and can be performed by any method.

  For example, the notch forming position can be selected according to the position of the temporary mark when the wafer is set in the notch processing apparatus. As a specific example, when a wafer is set in the notch processing apparatus, a notch is formed in the temporary mark closer to the notch processing means 54, and the user puts the wafer into the notch processing apparatus correspondingly. It can be set as the structure to set.

  Further, when the shape and / or size of the temporary mark is different as described above, the temporary mark detection means detects the difference, and a notch may be formed on the desired temporary mark side.

  According to the notch processing apparatus of the present embodiment described above, it is possible to detect a temporary mark with high accuracy in a short time and easily form a notch at the desired location.

  Conventionally, when chamfering a notch, a grindstone with a chamfering shaft in which a chamfering groove is formed on the side surface of the grindstone is used, and the surface of the notch portion is brought into contact with the groove. However, according to such a method, especially when the hardness of the wafer is high, the shape of the groove collapses or the wear of the grindstone progresses quickly, so it is necessary to replace the grindstone frequently. On the other hand, according to the notch processing apparatus of this embodiment, even when chamfering is performed using a disk-shaped rotating grindstone, the durability of the grindstone is higher than the conventional chamfering method, and the grindstone replacement frequency is high. Can be lowered. For this reason, productivity can be improved and the cost which a grindstone requires can also be reduced.

11A, 11B, 13A, 13B Crystal orientation planes 20, 51 Wafers 22A, 22B Main surface 30 Ingots 31, 32, 41, 42 Temporary mark 43 Main mark 52 Wafer support means 53 Temporary mark detection means 54 Notch processing means 541 Processing grindstone

Claims (7)

A method for manufacturing a wafer, comprising: slicing a crystal ingot having a crystal structure in which the same crystal orientation plane is arranged point-symmetrically; and then mirror polishing one side of the main surface of the wafer,
Two temporary marks indicating the respective directions of the crystal orientation planes are formed on the side surface of the ingot before slicing,
A method for producing a wafer, wherein when one surface of a main surface of a wafer is mirror-polished, a convex surface of the wafer is used as a polishing surface, and the orientation of the wafer is adjusted using a temporary mark indicating the direction of the polishing surface.   The method for manufacturing a wafer according to claim 1, further comprising a step of chamfering an end surface portion of the wafer and erasing the temporary mark.   The method for manufacturing a wafer according to claim 1 or 2, wherein the two temporary marks have different shapes and / or sizes.   2. The main mark is formed at a position of the temporary mark indicating the direction of the polishing surface, and when the one surface of the main surface of the wafer is mirror-polished, the orientation of the wafer is adjusted using the main mark. The manufacturing method of the wafer as described in any one of thru | or 3. 5. The wafer manufacturing method according to claim 4, wherein the notch processing device is used for forming the main mark.
Wafer support means for supporting the wafer;
Temporary mark detection means for detecting the position of one temporary mark formed on the wafer;
A notch processing means disposed at a position opposite to the temporary mark detection means, and forming a notch at the other temporary mark position and / or chamfering along the shape of the notch,
The notch processing means includes a disk-shaped processing grindstone,
The disc-shaped processing grindstone is a notch processing device in which a rotation direction of the disc-shaped processing grindstone and a surface of a wafer supported on the wafer support means are arranged so as to be orthogonal to each other.   The notch processing apparatus according to claim 5, wherein a plurality of contact-type displacement sensors arranged adjacent to each other are used as the temporary mark detection means.   The notch processing apparatus according to claim 6, wherein the temporary mark is an orientation flat, and a length of the chord of the orientation flat is 4 mm or more.

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