JP2009283545A - Method of manufacturing semiconductor apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a crack or chip of a semiconductor wafer, and to uniformize a shape of an end surface of each semiconductor wafer in continuously processing a plurality of semiconductor wafers. <P>SOLUTION: The semiconductor wafer 1 is sucked to a stage 5 with its rear face downward and rotated around the center of the wafer 1 as the center axis. An end surface grinding whetstone 10 is rotated around the center of the whetstone 10 while the center axis is put in a direction approximately vertical to the direction of the center axis of the rotation of the semiconductor wafer 1. Then, while the semiconductor wafer 1 is laterally moved, the end surface grinding whetstone 10 is vertically moved, thereby grinding the end surface 3 of the wafer 1 by bringing the whetstone 10 into contact with the end surface 3 of the wafer 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device for manufacturing a thin semiconductor device having a small device thickness.

  Conventionally, in order to maintain or improve the performance of a semiconductor element, a method of reducing the thickness of a semiconductor wafer serving as a substrate has been proposed. FIG. 9 is a flowchart showing a conventional method for manufacturing a semiconductor device. As shown in FIG. 9, first, a front surface element structure such as an integrated circuit is formed on the front surface of a semiconductor wafer (step S101), and a protective film is formed thereon (step S102). Next, a protective tape is applied to the front surface of the semiconductor wafer (step S103), the back surface of the semiconductor wafer is ground to a predetermined thickness (step S104), and etching or the like is performed on the ground surface (step S105). In this way, the semiconductor wafer is thinned.

  Next, an electrode is formed on the back surface of the semiconductor wafer (step S106), inspections such as characteristic inspection, appearance inspection, and reliability test are performed (step S107), and dicing is performed on individual chips (step S108). In this way, the semiconductor device is completed. Note that step S107 may be performed after step S108.

  FIG. 10 is a cross-sectional view showing the shape of a conventional thinned semiconductor wafer. As shown in FIG. 10, the semiconductor wafer 1 ground and thinned from the back side in steps S103 to S105 of FIG. 9 has a sharp knife edge shape on the end surface 31. For this reason, when the semiconductor wafer 1 is stored in the wafer carrier, or when the semiconductor wafer 1 is transported in the apparatus or between the apparatuses, the end surface 31 of the semiconductor wafer 1 comes into contact with a part of the wafer carrier or the apparatus, There is a problem that cracking occurs. In addition, there is a problem that the electrical characteristics of the device are deteriorated because the fragments generated by the chipping and cracking pierce the front surface element structure 2. Furthermore, if a piece pierces the suction table that holds the semiconductor wafer 1, the semiconductor wafer 1 that is held thereafter is also damaged, and the electrical characteristics of the plurality of semiconductor wafers 1 continuously deteriorate. There's a problem.

  As a means for solving such a problem, in the conventional method for manufacturing a semiconductor device shown in FIG. 9, the semiconductor wafer is either before, after, or before and after the step of grinding the back surface of the semiconductor wafer (step S104). There has been proposed a method of chamfering the end face of each of them (see, for example, Patent Document 1 and Patent Document 2 below).

  FIG. 11 or FIG. 12 is a cross-sectional view showing chamfering of the first conventional example or the second conventional example. As shown in FIG. 11, in the first conventional example, the back surface side of the semiconductor wafer 1 with the protective tape 4 affixed to the front surface is held down on the stage 5 and the center of the semiconductor wafer 1 is rotated. For example, the center axis is rotated as indicated by an arrow R3. Further, a grindstone having a groove on the side surface (hereinafter referred to as a groove-type grindstone) 20 that matches the finished shape of the end face 32 of the semiconductor wafer 1 is used as the center axis of rotation. Is rotated in the direction parallel to the central axis of rotation of the semiconductor wafer 1, for example, as indicated by an arrow R4. Then, the end face of the rotated semiconductor wafer 1 is moved as indicated by an arrow D3, for example, until it contacts the side surface of the rotated groove-type grindstone 20 within the front surface of the semiconductor wafer 1, Grinding is performed so that the end face of the semiconductor wafer 1 has a finished shape.

  Further, as shown in FIG. 12, a grindstone having a trapezoidal cross section (hereinafter referred to as a trapezoid grindstone) 21 is used with the center of the trapezoid grindstone 21 as a central axis of rotation, and this central axis is used to rotate the semiconductor wafer 1. In a direction parallel to the central axis, for example, rotation is performed as indicated by an arrow R6. Then, for example, as indicated by an arrow D4 until the end face 33 of the semiconductor wafer 1 rotated as indicated by an arrow R5 contacts the side surface of the trapezoidal grindstone 21 rotated within the front surface of the semiconductor wafer 1. It grinds so that an end surface may become an inclined surface.

  Furthermore, a method has been proposed in which a grindstone for grinding from the back side of a semiconductor wafer is used to grind the end surface of the semiconductor wafer in order to reduce the thickness of the semiconductor wafer. In this case, the semiconductor wafer is inclined so that the end surface of the semiconductor wafer is brought into contact with the grindstone, and the end surface is ground so as to be an inclined surface.

  By these methods, it is possible to remove the knife edge shape on the end face of the thinned semiconductor wafer and prevent cracking or chipping of the semiconductor wafer.

Japanese Patent Laid-Open No. 08-37169 JP-A-11-333680

  However, in the technique of Patent Document 1 or 2 described above, the end surface of the semiconductor wafer is ground by rotating the grindstone with the central axis of rotation of the grindstone parallel to the central axis of rotation of the semiconductor wafer. Wear occurs. FIG. 13 is a cross-sectional view showing a problem of the conventional chamfering process. As shown in FIG. 13, the regions of the side surfaces of the grindstones 20, 21 that are in contact with the end surfaces 32, 33 of the semiconductor wafer 1 are worn more than the other regions. For this reason, the shape of the side surfaces of the grindstones 20 and 21 is deformed every time chamfering is performed, and when chamfering is performed continuously on a plurality of semiconductor wafers 1, the shape of the end surface of the semiconductor wafer 1 varies. is there. Further, in order to suppress this variation, it is conceivable to perform grinding wheel correction (truing). However, since frequent truing is necessary, there is a problem that throughput is lowered and the life of the grinding wheel is shortened.

  In order to eliminate the above-mentioned problems caused by the prior art, the present invention prevents cracking and chipping of a semiconductor wafer, and uniformizes the shape of the end face of each semiconductor wafer when processing a plurality of semiconductor wafers continuously. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can be used.

  In order to solve the above-described problems and achieve the object, a method of manufacturing a semiconductor device according to the invention of claim 1 rotates the center of a semiconductor wafer as a central axis of rotation and uses the center of a grindstone as a central axis of rotation. A rotating step of rotating the grinding wheel so that the direction of the central axis of rotation of the grindstone is substantially perpendicular to the direction of the central axis of rotation of the semiconductor wafer, and rotating the semiconductor wafer while rotating the semiconductor wafer. And a chamfering step of chamfering the end surface of the semiconductor wafer in contact with a grindstone.

  According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first aspect of the present invention, wherein, in the chamfering process, the semiconductor wafer and the grindstone are disposed within the back surface of the semiconductor wafer. By moving at least one of them so as to approach each other and adjusting the distance to be moved, the height of the end face of the semiconductor wafer remaining without being ground is adjusted.

  According to a third aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the first or second aspect of the present invention, wherein, in the chamfering process, the semiconductor is oriented in a direction substantially perpendicular to the front surface of the semiconductor wafer. The grinding angle of the end face of the semiconductor wafer is adjusted by moving at least one of the wafer and the grindstone and adjusting the distance of the movement.

  According to a fourth aspect of the present invention, there is provided a semiconductor device manufacturing method according to any one of the first to third aspects, wherein, in the chamfering step, a corner on the back surface side of the end surface of the semiconductor wafer. Only chamfering is performed.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the fourth aspect of the present invention, wherein in the rotating step, the grindstone is moved from the back surface side of the semiconductor wafer toward the front surface side. In the chamfering step, the chamfering is performed by contacting the grindstone from the back side of the semiconductor wafer and grinding the end surface of the semiconductor wafer from the back side.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to any one of the first to fifth aspects, wherein the semiconductor wafer is manufactured before the rotating step or after the chamfering step. The method further includes a thinning step of grinding the entire back surface to make a thin plate.

  According to a seventh aspect of the present invention, there is provided a method for manufacturing a semiconductor device according to the sixth aspect of the present invention, wherein, in the chamfering step, the remaining height of the end face of the semiconductor wafer without being ground is reduced by the thinning. It is characterized by being smaller than the height remaining without being ground in the process.

  A method of manufacturing a semiconductor device according to an invention of claim 8 is the invention according to any one of claims 1 to 7, wherein after the chamfering process or after the chamfering process and the thinning process, A measuring step for measuring the shape of the end face of the semiconductor wafer and the shape of the grindstone, an acquisition step for acquiring a difference between a measured value in the measuring step and a desired shape of the end face of the semiconductor wafer; And a calculation step of calculating a correction value for chamfering the end face of the next semiconductor wafer based on the difference acquired by the acquisition step.

  According to a ninth aspect of the present invention, there is provided the semiconductor device manufacturing method according to any one of the first to eighth aspects, wherein the chamfering step measures the shape of the end face of the semiconductor wafer. And a step of determining whether or not the shape of the end face of the semiconductor wafer has reached a desired shape, and the shape of the end face of the semiconductor wafer has become a desired shape by the determining step. If it is determined, the chamfering process is terminated.

  According to the invention of each of the above-mentioned claims, since the corner portion of the end face of the semiconductor wafer can be ground into a desired shape, the corner portion of the end face of the semiconductor wafer can be prevented from becoming a knife edge shape. Further, since the grinding is performed with the rotation direction of the grindstone being substantially perpendicular to the rotation direction of the semiconductor wafer, the surface of the grindstone is uniformly worn, and uneven wear of the surface of the grindstone can be prevented. Therefore, when processing a plurality of semiconductor wafers using the same grindstone, the shape of the end face of each semiconductor wafer can be made substantially uniform. As a result, it is possible to prevent variations in the shape and diameter of the end face of each semiconductor wafer.

  Further, according to the above-described invention of claim 8, when continuously processing a plurality of semiconductor wafers, the shape of the end face of the semiconductor wafer subjected to the chamfering process and the shape of the grindstone are measured. Based on the measured value, a correction value from the reference dimension is calculated. The correction value can be fed back when processing the next semiconductor wafer. Therefore, the shape of the end face of each semiconductor wafer can be made substantially the reference dimension. For this reason, it can prevent that the shape and diameter of the end surface of each semiconductor wafer vary.

  Further, according to the above-described invention of claim 9, the end face of the semiconductor wafer is monitored with the reference dimension while the end face of the semiconductor wafer and the shape of the grindstone are monitored while chamfering the end face of the semiconductor wafer. The chamfering process can be terminated when the value reaches. Therefore, when processing is continuously performed on a plurality of semiconductor wafers, the shape of the end face of each semiconductor wafer can be set to a substantially standard dimension. For this reason, it can prevent that the shape and diameter of the end surface of each semiconductor wafer vary.

  According to the method of manufacturing a semiconductor device according to the present invention, when the semiconductor wafer is prevented from being cracked or chipped, and a plurality of semiconductor wafers are continuously processed, the shape of the end face of each semiconductor wafer can be made uniform. There is an effect that can be done.

  Exemplary embodiments of a method for manufacturing a semiconductor device according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that, in the following description of the embodiments and all the attached drawings, the same reference numerals are given to the same components, and duplicate descriptions are omitted.

(Embodiment 1)
FIG. 1 is a cross-sectional view illustrating the structure of the semiconductor device according to the first embodiment. As shown in FIG. 1, in the semiconductor device according to the first embodiment, the end surface 3 of the thinned semiconductor wafer 1 does not have a knife edge shape. That is, the end surface 3 of the semiconductor wafer 1 has a shape in which a corner is ground at a grinding angle θ from the surface on the back surface side while leaving a height h from the front surface side.

  2 and 3 are diagrams sequentially illustrating the method of manufacturing the semiconductor device according to the first embodiment. 2 is a plan view showing the method of manufacturing the semiconductor device according to the first embodiment, and the lower figure is a sectional view showing a sectional structure taken along the cutting line AA ′ in the upper figure. It is. First, as shown in FIG. 2, the front surface element structure 2 is formed on the front surface of the semiconductor wafer 1, and a protective member is attached to the front surface side of the semiconductor wafer 1. The protective member may be a protective tape or a liquid resin applied and cured. Here, the protective tape 4 will be used for explanation.

  Next, the back surface side of the semiconductor wafer 1 is faced down and sucked onto the stage 5, and the center of the semiconductor wafer 1 is rotated with the center axis of rotation as indicated by an arrow R1, for example. Moreover, the grindstone 10 for end surface grinding is rotated in the direction which passes the front surface side and back surface side of the semiconductor wafer 1, for example. That is, the end grinding wheel 10 is set to a direction substantially perpendicular to the direction of the center axis of rotation of the semiconductor wafer 1 with the center of the end grinding wheel 10 as the center axis of rotation as indicated by an arrow R2, for example. Rotate. Here, the direction of rotation of the grindstone 10 for end face grinding is preferably a direction from the back surface side of the semiconductor wafer 1 toward the front surface side. The reason is that if the direction of rotation of the grindstone 10 for end face grinding is the direction from the front surface side to the back surface side of the semiconductor wafer 1, the knife edge-shaped tip is directed to the inside of the semiconductor wafer 1. This is because a force is applied by the rotation of the grinding wheel 10 for end face grinding and a load is applied to the semiconductor wafer 1, so that the semiconductor wafer 1 may be cracked or chipped.

  Here, the shape of the grindstone 10 for end face grinding is, for example, a disk shape or a ring shape. As a ring-shaped grindstone, for example, there is one in which a ring-shaped grindstone is fixed to a metal frame. In addition, if a disk-shaped grindstone is used, even if the grindstone is worn, it can be used up to the center portion, so that the frequency of replacement can be suppressed. In addition, by fixing the grindstone to the frame, the accuracy of the rotating shaft of the grindstone can be increased, and attachment to the grinding device is facilitated. Furthermore, the strength of the grindstone can be increased by using a metal frame.

  In the end grinding grindstone 10, the surface in the thickness direction of the outer periphery (edge periphery) is a contact surface with the semiconductor wafer 1. This contact surface is preferably substantially flat. The grinding wheel 10 for end face grinding comes into contact with the end face of the semiconductor wafer and wears by grinding of the end face, but the semiconductor wafer comes into contact with the contact face almost uniformly. Wears almost uniformly toward the direction. That is, it wears so that the diameter of the grindstone 10 for end face grinding becomes small.

  Moreover, in said example, it is preferable that the thickness of the grindstone 10 for end surface grinding is about 5-10 mm, for example. The reason is that if the thickness (width) of the grindstone 10 for end face grinding is small, the strength of the grindstone becomes low and may be chipped during grinding. In addition, when the thickness (width) of the grindstone 10 for end face grinding is large, the contact amount with the semiconductor wafer becomes large, and it is necessary to increase the torque for rotating the grindstone and the semiconductor wafer during grinding. This is because if the rotation is performed with a large torque, position control during grinding described later becomes difficult, and the processing accuracy of the semiconductor wafer may be lowered.

  Furthermore, if the abrasive grains of the end surface grinding stone 10 are large, chipping of the semiconductor wafer is likely to occur when contacting the end surface of the semiconductor wafer. Therefore, it is desirable to use a grindstone larger than # 1000 (with fine abrasive grains) as the end face grinding grindstone 10.

  Then, while moving the semiconductor wafer 1 in the horizontal direction as indicated by an arrow D1, for example, the end grinding wheel 10 is moved in the vertical direction as indicated by an arrow D2 so that the end surface 3 of the semiconductor wafer 1 is moved to the end surface. The end face 3 of the semiconductor wafer 1 is ground by bringing the grinding stone 10 into contact therewith. At this time, for example, the central axis of rotation of the grindstone 10 for end face grinding is set at a position lower than at least the back side of the semiconductor wafer 1. Then, by adjusting the distance by which the semiconductor wafer 1 is moved in the lateral direction, the grinding height of the end face of the semiconductor wafer 1 (from the front face side of the region that remains without being ground when the end face of the semiconductor wafer is ground) To adjust the height h). That is, as the distance of the semiconductor wafer 1 moved in the lateral direction is increased, the region to be ground by the end surface grinding wheel 10 from the rear surface side of the end surface of the semiconductor wafer 1 is increased, so that the grinding height h is reduced. Note that the grinding height is a value smaller than the thickness remaining without being ground when the entire back surface of the semiconductor wafer 1 is ground. Further, the grinding angle of the end face of the semiconductor wafer 1 is adjusted by adjusting the distance by which the end face grinding grindstone 10 is moved in the vertical direction. That is, as the distance for moving the end surface grinding wheel 10 in the vertical direction is increased, the position of the semiconductor wafer 1 that contacts the end surface grinding wheel 10 is substantially the same as the front surface of the semiconductor wafer 1 of the end surface grinding wheel 10. As the angle approaches the apex in the direction of the right angle and the angle of the contact surface becomes gentle, the grinding angle θ becomes gentle.

  Here, when the protective tape 4 is applied to the entire front surface of the semiconductor wafer 1, the grinding height and the grinding angle are adjusted so that the edge grinding wheel 10 does not contact the protective tape 4. . In addition, when the protective tape 4 is affixed inside the outer end on the front surface side of the semiconductor wafer 1, both the front surface and the back surface of the semiconductor wafer 1 can be ground into an arbitrary shape. Moreover, the grindstone 10 for end surface grinding is any one of a metal bond grindstone, a resin bond grindstone, and a vitrified grindstone, for example.

  By doing so, as shown in FIG. 3, the semiconductor wafer 1 in which the grinding height of the end face 3 is h and the grinding angle is θ is formed. Then, by grinding the entire back surface of the semiconductor wafer 1 to a desired thickness and thinning the semiconductor wafer 1, the semiconductor device shown in FIG. 1 is completed.

  Next, a modification of the method for manufacturing the semiconductor device according to the first embodiment will be described. FIG. 4 is a cross-sectional view illustrating a modification of the method for manufacturing the semiconductor device according to the first embodiment. As shown in FIG. 4, in the modification of the method for manufacturing the semiconductor device according to the first embodiment, the entire rear surface of the semiconductor wafer 1 is ground to a desired thickness, and the semiconductor wafer 1 is thinned. 3 is chamfered.

  According to the first embodiment, when the end surface of the semiconductor wafer is ground by the end surface grinding wheel, the outer peripheral portion of the end surface grinding wheel is in uniform contact with the semiconductor wafer. Wear out. Therefore, uneven wear does not occur in the end surface grinding wheel, and the shape of the side surface of the end surface grinding wheel does not change. For this reason, even if chamfering is continuously performed on a plurality of semiconductor wafers using the same edge grinding wheel, the shape of the semiconductor wafer does not vary. Further, since the entire surface of the grindstone for end face grinding is worn almost uniformly, it is not necessary to perform truing, and the life of the grindstone can be extended.

(Embodiment 2)
FIG. 5 is a flowchart illustrating the method for manufacturing the semiconductor device according to the second embodiment. FIG. 5 shows a method of chamfering the end face of the semiconductor wafer performed before or after the entire surface of the semiconductor wafer is thinned. In the second embodiment, when continuously chamfering a plurality of semiconductor wafers, the shape of the end face of the semiconductor wafer subjected to the chamfering process and the shape of the grindstone for end face grinding are measured, and the next semiconductor wafer is measured. This is a method in which chamfering is performed by feeding back the deviation between the measured value and the reference dimension when chamfering the end face.

  As shown in FIG. 5, first, the semiconductor wafer is put into a chamfering apparatus (step S1). Next, the shape of the semiconductor wafer is measured (step S2). In step S2, the thickness and diameter of the semiconductor wafer are measured. Next, the center of the semiconductor wafer is detected (step S3). Then, the semiconductor wafer is mounted on the stage by a transfer mechanism such as a transfer arm (step S4).

  Next, it is determined whether or not there is a correction value when using the same end face grinding wheel last time (step S5). When there is no correction value in step S5 (step S5: No), the reference dimension is set as the setting condition (step S6). The reference dimension is a finished dimension of the end face of the semiconductor wafer and is information on the grinding height and the grinding angle. In Step S5, when there is no correction value, the end grinding wheel is not worn, for example, when a new end grinding wheel is used. On the other hand, when there is a correction value in step S5 (step S5: Yes), a value obtained by adding the correction value to the reference dimension is set as a setting condition (step S7). Then, based on the set conditions, the end face of the semiconductor wafer is ground (step S8).

  Next, it is determined whether or not the grinding of the end face of the semiconductor wafer is completed (step S9). In step S9, when the grinding is not finished (step S9: No), the process returns to step S8 and the grinding is continued. When the grinding is completed (step S9: Yes), the shape of the end face of the ground semiconductor wafer and the wear amount of the end face grinding wheel used for grinding are measured (step S10). In step S10, for example, the grinding height and grinding angle of the end face of the semiconductor wafer are measured by a displacement sensor, projection, image processing, linear gauge, or the like. Further, for example, the amount of wear of the end surface grinding wheel is measured by a displacement sensor or a linear gauge, or by moving the end surface grinding wheel so as to be brought into contact with a housing, a pedestal, or the like.

  Next, the measured value measured in step S10 is compared with the reference dimension (step S11), and a correction value is calculated (step S12). Next, the correction value calculated in step S12 is recorded in the recording unit included in the chamfering apparatus (step S13) to be used for the chamfering process of the end face of the next semiconductor wafer, and the series of processes is completed.

  In the flowchart of FIG. 5, it is determined in step S9 whether or not the grinding is finished, but the present invention is not limited to this. For example, before the grinding is finished, the process may proceed to step S10 and the subsequent processing may be performed. In this case, the end face grinding is completed by satisfying the setting condition.

  In the flowchart of FIG. 5, the process proceeds to step S10 every time grinding of one semiconductor wafer is completed in step S9. However, the present invention is not limited to this. For example, a configuration may be adopted in which a predetermined number of semiconductor wafers are waited for grinding, and after the predetermined number of semiconductor wafers have been ground, the process proceeds to step S10. In this case, since it is not necessary to calculate a correction value for each semiconductor wafer, throughput is improved.

  According to the second embodiment, when the end faces of a plurality of semiconductor wafers are continuously chamfered using the same end face grinding grindstone, the shape of the end face of each semiconductor wafer can be set to the reference dimension. . For this reason, since the shape of each semiconductor wafer becomes substantially the same, it can prevent that the shape and diameter of an end surface vary for every semiconductor wafer. Also, when grinding the end face of the semiconductor wafer based on the set condition, for example, it is not necessary to change the set condition between the start and end of the grinding of the end face of one semiconductor wafer. It becomes easy to control. This eliminates the need for a device or a program for performing complex control, thereby reducing costs.

(Embodiment 3)
FIG. 6 is a flowchart illustrating the method for manufacturing the semiconductor device according to the third embodiment. FIG. 6 shows a method of chamfering the end surface of the semiconductor wafer performed before or after the entire surface of the semiconductor wafer is thinned. In the third embodiment, when chamfering a semiconductor wafer, the shape of the end face is monitored while grinding the end face of the semiconductor wafer, and the grinding is finished when the end face shape reaches the reference dimension. is there. Note that steps S21 to S24 in the flowchart of FIG. 6 are the same as steps S1 to S4 in the flowchart of FIG.

  After mounting the semiconductor wafer on the stage in step S24, the end face of the semiconductor wafer is ground (step S26) using the reference dimension as a setting condition (step S25). Then, the shape of the end face of the semiconductor wafer is measured (step S27). In step S27, although the details will be described later, the measuring unit for measuring the end face is provided with an air nozzle, and air is blown from the air nozzle to dry the end face of the semiconductor wafer, and then the shape of the end face is measured. Do. Further, in step S27, for example, one measurement may be performed while the semiconductor wafer makes one round.

  Next, the measurement value measured in step S27 is compared with the reference dimension (step S28), and it is determined whether or not the measurement value has reached the reference dimension (step S29). In step S29, when the measured value does not reach the reference dimension (step S29: No), the process returns to step S26 and the subsequent processing is repeated.

On the other hand, when the measured value reaches the reference dimension in Step S29 (Step S29: Yes), the grinding of the end face is finished (Step S30). Then, the amount of wear of the grindstone for end face grinding is measured (step S31), and a correction value is calculated based on the lateral fixed value measured in step S27 and step S31 and the reference dimension (step S32). Next, the setting condition is changed to a value obtained by adding the correction value calculated in step S32 to the reference dimension (step S33), and the series of processes is terminated.

  In the flowchart of FIG. 6, the processing in steps S31 to S33 may be omitted, and the series of processing may be terminated when grinding is completed in step S30.

  Next, the processing of step S26 and step S27 in the flowchart of FIG. 6 will be described in detail. FIG. 7 is a cross-sectional view illustrating in detail a grinding process and a measurement process of the end face of the semiconductor wafer in the method of manufacturing a semiconductor device according to the third embodiment. As shown in FIG. 7, the grinding process and the measurement process of the end surface 3 of the semiconductor wafer 1 are performed simultaneously. The semiconductor wafer 1 is held on the stage 5 and rotated, for example, as indicated by an arrow R1. In the grinding process, for example, as shown in the first embodiment, the cooling water 12 is sprayed from the cooling nozzle 11 to the end surface 3 of the semiconductor wafer 1 to the end surface 3 of the semiconductor wafer 1 and the grinding wheel 10 for end surface grinding. As shown in R2, the end surface grinding wheel 10 is rotated in a direction substantially perpendicular to the direction of rotation of the semiconductor wafer 1, and the end surface of the semiconductor wafer 1 is ground.

  On the other hand, in the measurement process, air 14 is blown from the air nozzle 13 to the end face 3 of the semiconductor wafer 1 to dry the end face 3 of the semiconductor wafer 1 wetted by the cooling water 12 in the grinding process. Then, the end surface 3 of the dried semiconductor wafer 1 is measured by, for example, the displacement sensor 15 or the like.

  FIG. 8 is a cross-sectional view showing in detail an example of a method for measuring the shape of the end face of the semiconductor wafer. In FIG. 8, a method for measuring the shape of the end face of the semiconductor wafer using a displacement sensor will be described. As shown in FIG. 8, for example, light 16 is irradiated from the displacement sensor 15 to the end surface of the semiconductor wafer 1. Then, the reflected light 17 of the irradiated light 16 is received, and the grinding height h and the grinding angle θ of the end surface 3 of the semiconductor wafer 1 are measured by the angle of the reflected light 17.

  According to the third embodiment, the same effect as in the second embodiment can be obtained. Furthermore, since the shape of the end face is measured at an appropriate time while grinding the end face of the semiconductor wafer, the shape of the end face of each semiconductor wafer can be made more uniform.

  In each of the above embodiments, the movement (adjustment) in the horizontal direction is performed by moving the semiconductor wafer, and the movement (adjustment) in the vertical direction is performed by moving the grindstone. However, the present invention is not limited to this. For example, contrary to the above, the movement (adjustment) in the horizontal direction may be performed by moving the grindstone, and the movement (adjustment) in the vertical direction may be performed by moving the semiconductor wafer. Alternatively, one of the semiconductor wafer and the grindstone may be rotated at a fixed position, that is, only the other of the wafer or the grindstone may be moved in the vertical and horizontal directions with the rotation axis as the fixed position.

  Further, as in the first or third embodiment, when the amount of grinding is determined by measuring the shape of the end surface of the semiconductor wafer, the rotation axis of the semiconductor wafer is set at a fixed position, and the end surface grinding wheel is moved up and down, left and right. In this way, the semiconductor wafer end face shape detection mechanism (for example, the displacement sensor 15 in FIG. 7 or FIG. 8) can be fixed, so that the detection accuracy is improved.

  Further, the grinding of the end face of the semiconductor wafer may be performed before the grinding process of the back face of the semiconductor wafer. Here, the grinding process of the back surface of the semiconductor wafer may be moved back and forth according to other processes of the semiconductor manufacturing process.

  As described above, the method for manufacturing a semiconductor device according to the present invention is useful for manufacturing a semiconductor device having a thin device thickness, and is particularly suitable for manufacturing a power semiconductor device used for a power conversion device or the like. ing.

1 is a cross-sectional view showing a structure of a semiconductor device according to a first embodiment; FIG. 3 is a diagram showing a method for manufacturing the semiconductor device according to the first embodiment. FIG. 3 is a diagram showing a method for manufacturing the semiconductor device according to the first embodiment. FIG. 9 is a cross-sectional view showing a modified example of the method for manufacturing the semiconductor device according to the first embodiment. 6 is a flowchart illustrating a method for manufacturing a semiconductor device according to a second embodiment; 10 is a flowchart illustrating a method for manufacturing a semiconductor device according to a third embodiment; FIG. 6 is a cross-sectional view illustrating in detail a grinding process and a measurement process for an end face of a semiconductor wafer in a method for manufacturing a semiconductor device according to a third embodiment; It is sectional drawing shown in detail about an example of the measuring method of the shape of the end surface of a semiconductor wafer. It is a flowchart shown about the manufacturing method of the conventional semiconductor device. It is sectional drawing shown about the shape of the conventional semiconductor wafer thinned. It is sectional drawing shown about the chamfering of a 1st prior art example. It is sectional drawing shown about the chamfering of a 2nd prior art example. It is sectional drawing shown about the problem of the conventional chamfering process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 2 Front surface element structure 3 End surface 4 Protection tape 5 Stage 10 Grinding wheel for end surface grinding

Claims (9)

The center of the semiconductor wafer is rotated as the center axis of rotation, the center of the grindstone is the center axis of rotation, and the direction of the center axis of rotation of the grindstone is substantially perpendicular to the direction of the center axis of rotation of the semiconductor wafer. Rotating process to rotate,
A chamfering process for chamfering the end face of the semiconductor wafer by bringing the semiconductor wafer that has been rotated into contact with the grindstone that has been rotated, and
A method for manufacturing a semiconductor device, comprising:   In the chamfering process, at least one of the semiconductor wafer and the grindstone is moved closer to each other within the surface of the back surface of the semiconductor wafer, and the moving distance is adjusted, thereby grinding the end surface of the semiconductor wafer. The method for manufacturing a semiconductor device according to claim 1, wherein the remaining height is adjusted.   In the chamfering step, by moving at least one of the semiconductor wafer and the grindstone in a direction substantially perpendicular to the front surface of the semiconductor wafer and adjusting the distance to be moved, the end surface of the semiconductor wafer is adjusted. The method for manufacturing a semiconductor device according to claim 1, wherein a grinding angle is adjusted.   4. The method of manufacturing a semiconductor device according to claim 1, wherein, in the chamfering process, chamfering is performed only on a corner portion on a back surface side of an end surface of the semiconductor wafer. 5. In the rotation step, the grindstone is rotated in a direction from the back surface side of the semiconductor wafer toward the front surface side,
5. The semiconductor device according to claim 4, wherein in the chamfering process, the grindstone is chamfered by contacting the grindstone from the back surface side of the semiconductor wafer and grinding the end surface of the semiconductor wafer from the back surface side. Manufacturing method.   6. The method according to claim 1, further comprising a thinning step of grinding the entire back surface of the semiconductor wafer to make a thin plate before the rotating step or after the chamfering step. The manufacturing method of the semiconductor device of description.   7. The semiconductor device according to claim 6, wherein, in the chamfering process, a height of the end face of the semiconductor wafer that remains without being ground is smaller than a height that remains without being ground in the thinning process. Production method. After the chamfering process or between the chamfering process and the thinning process,
A measuring step for measuring the shape of the end face of the semiconductor wafer and the shape of the grindstone;
An acquisition step of acquiring a difference between a measurement value in the measurement step and a desired shape of the end face of the semiconductor wafer;
Based on the difference acquired by the acquisition step, a calculation step for calculating a correction value when chamfering the end surface of the next semiconductor wafer; and
The method for manufacturing a semiconductor device according to claim 1, further comprising: The chamfering process includes
An end face measuring step for measuring the shape of the end face of the semiconductor wafer;
A determination step of determining whether or not the shape of the end face of the semiconductor wafer has reached a desired shape;
Further including
9. The semiconductor according to claim 1, wherein the chamfering step is terminated when it is determined by the determination step that the shape of the end face of the semiconductor wafer has become a desired shape. Device manufacturing method.

Images