JP2007200917A - Wafer division method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and smoothly divide a wafer where a reinforcing part is installed at an outer peripheral edge and a metal film is arranged at a rear face from a rear side. <P>SOLUTION: Streets 2a and 2b of the wafer 1 exposed to a surface are seen through from the rear side, and street recognition grooves 7a and 7b are formed on the center line of the streets 2a and 2b. The device region 1a of the wafer 1 is ground, and the reinforcing part is formed on the outer peripheral edge of the wafer 1. The device region of the wafer 1 is coated with the metal film. The streets 2a and 2b are ground with positions of the street recognition grooves 7a and 7b as reference and they are divided into individual devices. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of dividing a semiconductor wafer (hereinafter, abbreviated as “wafer”) that is divided into a large number of semiconductor chips, and more particularly, to a wafer in which a ring-shaped reinforcing portion is formed on the outer periphery. It relates to a method of dividing smoothly.

  As a method of thinning a wafer on which a semiconductor device is formed on the front surface, a ring-shaped reinforcing portion is formed by processing only the back surface corresponding to the device formation area of the wafer to a required thickness and making the outer periphery thicker than the device formation area. The method of leaving is known (for example, patent documents 1 and 2). Since such a wafer is improved in strength and rigidity by the reinforcing portion, it is difficult to break during handling and various treatments. For this reason, the wafer as described above is particularly suitable for the case where an electrode or a heat dissipation means is provided by providing a metal film such as gold on the back surface by a method such as sputtering or vapor deposition. In addition, in a conventional wafer having no reinforcing portion, a protective tape was sometimes attached to the surface in order to supplement strength and rigidity. However, since the protective tape is insufficient in heat resistance, when performing sputtering or the like. Although it is necessary to set the temperature low, and it takes a long time for sputtering, such a problem is solved.

JP 2004-281551 A (abstract) JP 2005-123425 A (Abstract)

By the way, in the method of separating a wafer having a reinforcing portion provided with a metal film on the back surface,
There are two methods: cutting from the front surface and cutting from the back surface. In the former method, the reinforcing portion is cut into a ring shape, and the back surface of the wafer is adsorbed and cut (diced) along a planned cutting line such as a street appearing on the surface. Note that the reinforcing portion is also cut off after dicing. Also, in the latter method, the back side of the reinforcing part is ground to remove the metal film, and the surface street is permeated with an infrared camera to recognize the planned cutting line, and dicing is performed from the back side of the wafer. To do.

  However, in order to cut the reinforcing portion into a ring shape, a dedicated cutting device and a mechanism for removing the unnecessary portion in the ring shape are required, which increases the equipment cost. In addition, in order to grind the metal film on the back surface of the reinforcing part, a grinding wheel having a coarse particle diameter that is not easily clogged and suitable for metal grinding is used, and it is suitable for seeing through the ground surface with an infrared camera. Mirror finish grinding is required, and grinding means with two or more steps is required. Furthermore, since the street does not necessarily exist on the front surface side of the reinforcing portion, alignment may not be possible even if the back surface side of the reinforcing portion is ground. Accordingly, an object of the present invention is to provide a method for easily and smoothly dividing a wafer having a reinforcing portion and having a metal film on the back surface from the back surface side.

  The present invention provides a wafer having, on the surface, a device region in which a plurality of devices are defined by a street in a first direction and a street in a second direction, and an outer peripheral surplus region surrounding the device region. A method of dividing a wafer into individual devices, wherein the wafer surface is sucked and the wafer is seen through from the back side, and the surplus of the back surface of the wafer corresponding to the street in the first direction and the street in the second direction Street recognition groove forming process for forming street recognition grooves in the area, concave processing process for grinding the back surface corresponding to the device area to form a ring-shaped reinforcement in the outer peripheral surplus area, and coating the back surface of the wafer with a metal film The metal film coating process, and the surface of the wafer is adsorbed to detect the street recognition groove from the back surface of the wafer. It is characterized by having a direction of streets and the wafer cutting step of cutting the wafer along the streets in the second direction.

  In the present invention, the street recognition groove is formed in the reinforcing portion through the street from the back side of the wafer, and the wafer is cut along the streets in the first and second directions based on the position of the street recognition groove. There is no need for a step of grinding the back side of the reinforcing portion to remove the metal film at that portion. Therefore, the wafer dividing process is greatly simplified, and can be applied to any wafer. Note that at least one street recognition groove may be formed in the first direction and the second direction. In some cases, the street cannot be clearly seen. In such a case, a street is assumed from a characteristic pattern (alignment mark) provided at a corner or the like of the device, and a street recognition groove can be formed with reference to the alignment mark. Therefore, the “street” of the present invention is a concept including an alignment mark.

  In the present invention, a street recognition groove forming step can be performed after the concave processing step, and then a metal film coating step can be performed. In this order of the steps, the street recognition groove can be formed shallow and short. Since the metal film is a very thin film formed by vapor deposition or sputtering, the street recognition groove is not filled with the metal film and cannot be recognized.

Contrary to the above, a concave processing step can be performed after the street recognition groove forming step.
In this case, a thinning process for grinding the entire back surface of the wafer may be provided between the street recognition groove forming process and the concave processing process. In such a case, the street recognition groove is formed deeply. It is necessary to make the street recognition groove remain in the reinforcing portion after the concave processing step.

  In the wafer cutting process, the reinforcing portion having a thickness larger than that of the device region is cut. Therefore, it is preferable to form a groove in advance in the reinforcing portion using a thick blade. That is, the reinforcing portion is cut along a street in the first direction and a street in the second direction at a depth that does not reach the device region from the back surface of the wafer (first cutting step). Next, using a blade thinner than the cutting blade used in the first cutting process, the wafer is completely cut along the reinforcing groove formed in the first cutting process and divided into individual devices (first device). 2 cutting process). In such an aspect, cutting of the reinforcing portion can be performed quickly, and consumption of the blade can be suppressed. In addition, since the device region can be cut with a thinner blade, the number of semiconductor devices obtained by narrowing the street width can be increased.

  In the above aspect, the second cutting process can be performed after the first cutting process is completed. In addition, by using a cutting apparatus having two rotating blades that rotate, the first cutting step and the second cutting step can be performed with two cutting blades.

  According to the present invention, since the process of grinding the back side of the reinforcing portion and removing the metal film at that portion is not required, the wafer dividing process is greatly simplified and can be applied to any wafer. An effect such as that is obtained.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
[1] Semiconductor Wafer FIGS. 1A and 1B are a perspective view and a side view, respectively, of a disk-shaped semiconductor wafer (hereinafter abbreviated as a wafer) 1 which is a substrate of this embodiment. The wafer 1 is a silicon wafer or the like and has a thickness of about 600 to 700 μm. A large number of rectangular semiconductor chips 3 are partitioned on the surface of the wafer 1 by lattice-shaped first and second streets 2a and 2b. An electronic circuit is formed.

  A V-shaped orientation notch 4 is formed on the side surface of the wafer 1, and a protective seal 5 is attached to the surface. The wafer 1 is ground and thinned to a target thickness (for example, about 50 to 100 μm), and then cut and divided along the street 2 to be separated into a large number of semiconductor chips 3. FIG. 2 shows a cutting device for separating the semiconductor chip 3 into individual pieces. Hereinafter, the cutting apparatus 10 will be described.

[2] Cutting Device The cutting device 10 has a substantially rectangular parallelepiped base 11, a positioning mechanism 20 is provided on the horizontal upper surface of the base 11, and a clockwise rotation is provided around the positioning mechanism 20. A cassette 30, a cutting mechanism 40, and a cleaning unit 50 are arranged. The wafer 1 is installed at a predetermined position on the base 11 in a state where a plurality of wafers 1 are accommodated in the cassette 30.

  One wafer 1 is taken out from the cassette 30, and the wafer 1 is transferred to the cutting mechanism 40 via the positioning mechanism 20, and the wafer 1 is cut by the cutting mechanism 40. Thereafter, the wafer 1 is transferred to the cleaning unit 50 via the positioning mechanism 20 and cleaned by the cleaning unit 50. The cleaned wafer 1 is returned to the cassette 30 via the positioning mechanism 20 once again. A transfer robot for transferring the wafer 1 is provided on the base 11 (not shown). Below, the cassette 30, the positioning mechanism 20, the cutting mechanism 40, and the washing | cleaning unit 50 are demonstrated according to the transfer order of the wafer 1. FIG.

A. Cassette The cassette 30 is portable, and stores a plurality of wafers 1 in a stacked manner. The cassette 30 is detachably set on a predetermined cassette installation portion on the base 11. The cassette 30 has a pair of parallel cases 31 that are spaced apart from each other, and a plurality of racks 32 are provided in the vertical direction on the opposing surfaces inside the cases 31. In these racks 32, a wafer 1 having a horizontal posture with its surface facing upward is slidably inserted. The cassette 30 is set on the cassette installation portion on the base 11 so that the sliding direction of the wafer 1 is parallel to the Y direction. The wafer 1 in the cassette 30 is transferred to the positioning mechanism 20 by the transfer robot.

B. Positioning Mechanism The positioning mechanism 20 is configured such that a pair of parallel guide bars 21 extending in the Y direction move in the X direction orthogonal to the Y direction while linking so as to approach or separate from each other. The wafer 1 is placed on the base 11 between the guide bars 21 and is sandwiched between the approaching guide bars 21, whereby the relay position to the cutting mechanism 40, the cleaning unit 50, and the cassette 30 is determined.

C. Cutting Mechanism The cutting mechanism 40 includes a disk-shaped chuck table 42 that is rotatably provided on a rectangular table base 41, and a cutting unit 45 that is disposed above the chuck table 42. The table base 41 is provided on the base 11 so as to be movable in the X direction via a guide rail (not shown), and is reciprocated by a reciprocating drive mechanism (not shown). The chuck table 42 has a horizontal upper surface and is supported on the table base 41 so as to be rotatable about the Z direction (vertical direction) as an axis, and is rotated clockwise or counterclockwise by a rotation driving mechanism (not shown).

  The chuck table 42 is a well-known vacuum chuck type and has a large number of fine suction holes communicating with the front and back surfaces, and an air suction port of a vacuum device (not shown) is arranged on the back surface side. The wafer 1 is placed on the upper surface of the chuck table 42 from the state in which the vacuum apparatus is operated, and is sucked and held. A bellows-like cover 43 is provided at both ends in the moving direction of the table base 41 so as to be able to extend and contract to block the moving path of the table base 41 and prevent dust and the like from entering.

  The cutting unit 45 includes a cylindrical spindle 46 whose axial direction is held parallel to the Y direction, and a cutting blade 47 attached to one end of the spindle 46. As shown in FIG. 3, the cutting blade 47 is a so-called hub blade fixed to the periphery of the umbrella-shaped hub 81. The hub 81 is fixed to a tip end of a rotating shaft 82 that is driven to rotate by a motor (not shown) accommodated in the spindle 46 by a clamping metal 83. The rotation direction of the cutting blade 47 is one direction, and the rotation shaft 82 is coaxially accommodated in the spindle 46. The spindle 46 reciprocates in the Y direction and moves up and down in the Z direction while keeping the axial direction parallel to the Y direction on a frame (not shown) provided on the base 11. It is supported. The frame is provided with a drive mechanism (not shown) that moves the spindle 46 in those directions.

  A blade cover 48 is attached to the end of the spindle 46 on the side where the cutting blade 47 is mounted. The blade cover 48 is provided with cutting water nozzles 49A and 49B for supplying cutting water to the wafer 1 for lubrication, cooling and cleaning during cutting. An infrared camera 44 is attached to the side of the blade cover 48 adjacent to the cutting water nozzle 49B. The infrared camera 44 irradiates the wafer 1 attracted to the chuck table 42 with the back side facing up, and shoots the infrared ray reflected on the street printed on the surface of the wafer 1.

  According to the cutting mechanism 40 having the above configuration, the wafer 1 is attracted and held on the chuck table 42, and the wafer 1 is cut by cutting the cutting blade 47 rotated at high speed with respect to the wafer 1. The cutting position of the cutting blade 47 in the Y direction is adjusted by moving the spindle 46 in the Y direction, and the cutting depth is adjusted by moving the spindle 46 in the Z direction.

D. Cleaning unit The cleaning unit 50 includes a vacuum chuck type chuck table 51 similar to the chuck table 42 of the cutting mechanism 40, and a cleaning water nozzle and an air nozzle (both not shown) disposed around the chuck table 51. It has. The chuck table 51 attracts and holds the wafer 1 on a horizontal upper surface, and is rotated at a high speed by a rotation driving mechanism (not shown). Washing water is jetted from the washing water nozzle to the wafer 1 held on the chuck table 51 and rotated at a high speed, whereby the wafer 1 is washed. Then, the rotation of the chuck table 51 is continued and the injection of the cleaning water is stopped to spin out the cleaning water, and further, the air is injected from the air nozzle onto the wafer 1, whereby the cleaned wafer 1 is dried. The

[3] Grinding apparatus The wafer 1 is ground and thinned, and in the process, a concave process is performed to form a ring-shaped reinforcing portion on the outer peripheral edge. FIG. 5 is a view showing the wafer 1 subjected to concave processing. By the concave processing, the device region 1a of the wafer 1 is ground, and a reinforcing portion 1b having a thickness larger than that of the device region is formed on the outer peripheral edge of the wafer 1. FIG. 4 is a view showing a grinding apparatus for performing such concave machining. In FIG. 4, reference numeral 60 denotes a grinding unit of the grinding apparatus. The grinding unit 60 is configured to be movable up and down and movable in the lateral direction. In the grinding unit 60, a grinding wheel 65 that holds a large number of chip-like grindstones 64 is attached to a rotating shaft of a cylindrical spindle 61 via a wheel mount 63. In the figure, reference numeral 66 denotes a motor for rotating the rotating shaft of the spindle 61.

  Here, the rotational diameter of the grindstone 64 of the grinding unit 60 is approximately half the diameter of the wafer 1 in order to grind the device region 1a of the wafer 1 without producing an unground portion. Further, since the grinding unit 60 is movable in the lateral direction, the entire back surface of the wafer 1 can be ground by moving laterally from the position shown in FIG. 4B by the width of the reinforcing portion 1b. Reference numeral 54 denotes a chuck table that sucks the wafer 1. In addition, after reducing the whole thickness of the wafer 1 with a grinding apparatus different from that shown in FIG.

[4] Wafer Dividing Processing Next, a procedure for dividing the wafer 1 into individual devices will be described in the order of a street recognition groove forming step, a concave processing step, a metal film covering step, and a wafer cutting step.

1. Street Recognition Groove Forming Step First, in the cutting apparatus 10, one wafer 1 in the cassette 30 is horizontally placed with the back surface facing upward between the two guide bars 21 in the positioning mechanism 20 by the transfer robot. Placed in. Then, the two guide bars 21 move while being linked in a direction in which they approach each other, and the movement is stopped when the both guide bars 21 come into contact with the wafer 1 and are sandwiched therebetween. As a result, the wafer 1 is positioned at the transfer start position of the cutting mechanism 40 to the chuck table 42.

  The chuck table 42 has been sucked in advance, and the wafer 1 is transferred onto the chuck table 42 by a transfer robot and sucked and held. Next, the chuck table 42 is rotated, and the orientation notch 4 of the wafer 1 is detected by an appropriate means such as a contact sensor, so that the orientation notch 4 is completely stopped in the X direction. Next, the table base 41 is moved in the X direction and the spindle 46 is appropriately moved in the Y direction, and the wafer 1 is stopped below the infrared camera 44. In this state, the infrared camera 44 photographs the wafer 1. FIG. 7 shows a photographed image by the infrared camera 44. As shown in this figure, the first and second streets 2 a and 2 b appearing on the surface of the wafer 1 are taken through by the infrared camera 44. The captured image is analyzed, and the first street 2a closest to the center of the wafer 1 is selected, and the distance between the center line and the orientation notch 4 is measured. Similarly, the second street 2b closest to the center of the wafer 1 is selected, and the distance between the center line and the orientation notch 4 is measured. Thereby, the processing positions of the first and second street recognition grooves 7a and 7b are grasped.

  Next, the chuck table 42 and the spindle 46 are respectively moved in the Y direction and the X direction, and the cutting blade 47 is positioned immediately above the processing position of the first street recognition groove 7 a of the wafer 1. When the cutting blade 47 is thus set at the processing position, the cutting blade 47 is rotated at a high speed, and the cutting blade 47 is lowered and cut into the wafer 1 to a predetermined depth. In this state, the chuck table 42 is moved in the X direction to cut the first street recognition groove 7a. Next, the chuck table is rotated by 90 °, and the second street recognition groove 7b is cut in the same manner as described above. FIG. 6 shows a state in which the first and second street recognition grooves 7a and 7b are formed on the wafer 1. FIG. The thickness and the cutting depth of the cutting blade 47 need only be such that the infrared camera 44 can identify the first street recognition groove 7a after the back surface of the wafer 1 is coated with a metal film.

  Next, the wafer 1 in which the first and second street recognition grooves 7a and 7b are formed is moved again to the positioning mechanism 20 by the transfer robot, where the transfer start position of the cleaning unit 45 to the chuck table 51 is determined. Then, it is moved onto the chuck table 51 of the cleaning unit 45 by the transfer robot. The wafer 1 is sucked and held on the chuck table 51, and then the cleaning water is jetted from the cleaning water nozzle to the rotating wafer 1 for a predetermined time while rotating the chuck table 51 at a high speed. As a result, the water present on the surface of the wafer 1 and the formed grooves 4 is spun out, and the cutting waste and dust are removed together with the water, whereby the wafer 1 is cleaned.

  While the chuck table 51 is continuously rotated, air is jetted from the air nozzle to the wafer 1, whereby the wafer 1 is dried. The wafer 1 cleaned in this way is accommodated in the cassette 30 from the cleaning unit 50 via the positioning mechanism 20 by the transfer robot, and is transferred to the concave processing step by the next back surface grinding.

2. Concave processing step In the concave processing step, as shown in FIG. 4, the surface of the wafer 1 is attracted and held on a chuck table 54 of a vacuum chuck type, and the grinding wheel is rotated at high speed with respect to the surface of the wafer 1. By pressing the 65 grindstones 64, only the device region 1a on the back surface of the wafer 1 is ground. By this concave processing step, the device region 1a has a final thickness. FIG. 7 is a view showing the wafer 1 subjected to the concave processing step. As shown in this figure, the reinforcing portion 1b of the wafer 1 is left with the first and second street recognition grooves 7a and 7b in the street recognition groove forming step.

3. Metal film coating step The wafer 1 subjected to the concave processing step is carried into a sputtering apparatus, where an appropriate metal film is coated on the entire back surface. This metal film is used as an electrode or a heat dissipation means. At the time of sputtering, since the protective tape 5 attached to the surface of the wafer 1 is peeled off, it is possible to perform sputtering at a predetermined high temperature.

4). Wafer Cutting Process The wafer 1 coated with a metal film is covered with a protective tape 5 on the surface thereof, accommodated in a cassette 30, and transported to the cutting apparatus 10 again. Since the protective rib 1b of the wafer 1 is not ground, the first and second street recognition grooves 7a and 7b are left there. Then, the cutting apparatus 10 performs cutting to separate the wafer 1 into individual semiconductor chips 3 using the first and second street recognition grooves 7a and 7b as a reference of the cutting position. In this wafer cutting step, first, a reinforcing portion cutting step of cutting the reinforcing portion 1b of the wafer 1 using a thick cutting blade is performed, and then cutting to the surface is performed using a thin cutting blade. Perform device area cutting process.

4-1. Reinforcing section cutting process When the wafer 1 is attracted to the chuck table 42 of the cutting apparatus 10 in the same manner as the street recognition groove forming process described above, the chuck table 42 and the spindle 46 of the cutting unit 45 move in the X and Y directions, respectively. Then, the cutting blade 47 is positioned immediately above the processing position of the wafer 1. Note that the control device of the cutting device 10 stores the positions of the first and second street recognition grooves 7a and 7b, and the cutting device 10 detects the position of the orientation notch 4, for example, to Such positioning can be performed.

  First, the first street recognition groove 7 a is cut by the cutting blade 47. In this case, the thickness of the cutting blade 47 is, for example, 200 to 300 μm. Further, the cutting depth of the cutting blade 47 is set to a depth at which the cutting blade 47 does not contact the device region 1 a of the wafer 1. After cutting the first street recognition groove 7a, the chuck table 42 or the spindle 46 is moved to cut the adjacent first street 2a. When all the first streets 2a have been cut, the chuck table 42 is rotated by 90 °, the second street recognition grooves 7b are cut, and the adjacent second streets 2b are cut. By cutting the reinforcing portion 1b of the wafer 1 in this way, as shown in FIG. 8, processed grooves 8a and 8b overlapping the first and second streets 2a and 2b are formed in the reinforcing portion 1b.

4-2. Device Area Cutting Step Next, the cutting blade 47 is replaced with one having a thickness of 20 to 30 μm, for example, and the device area 1a is cut. In this cutting process, the cutting depth is set such that the cutting blade 47 reaches the protective seal 5. Then, as shown in FIG. 9 (b), a processed groove 9a (9b) that is narrower and deeper than the processed groove 8a (8b) cut in the reinforcing portion cutting step is formed. The wafer 1 is divided into individual semiconductor chips 3 by performing this cutting process on all of the first and second streets 2a and 2b.

  In the wafer dividing method as described above, the first and second street recognition grooves 7a and 7b are formed in the reinforcing portion 1b by seeing through the first and second streets 2a and 2b from the back side of the wafer 1 by the infrared camera 44. Since the wafer 1 is cut along the first and second streets 2a and 2b based on the positions of the first and second street recognition grooves 7a and 7b, the back side of the reinforcing portion 1b is ground to A process of removing the metal film is not necessary. Therefore, the dividing process of the wafer 1 is greatly simplified, and any wafer 1 can be handled.

  In particular, in the above embodiment, the cutting process of the wafer 1 is divided into the reinforcing part cutting process using the thick cutting blade 47 and the device area cutting process using the thin cutting blade 47, so that the reinforcing part 1b is cut quickly. There is an advantage that consumption of the cutting blade 47 can be suppressed.

[5] Modified Example In the embodiment, the concave processing step is performed after the street recognition groove forming step, but the order can be reversed. In this case, since the thickness of the reinforcing portion can be reduced in the thinning process by grinding, the reinforcing portion cutting process can be performed quickly and consumption of the cutting blade can be suppressed. Further, after the deep street recognition groove forming step is performed, the back surface of the wafer can be ground to reduce the thickness, and then the concave processing step can be performed. Further, the street recognition groove forming step can be performed after the wafer is thinned. In addition, it is possible to perform a concave processing step after thinning the wafer and then perform a street recognition groove forming step.

  In the embodiment, the device region cutting step is performed after the reinforcing portion cutting step is finished. However, these two cutting steps can be performed in a series of steps. FIG. 10 shows a cutting apparatus 10 ′ capable of performing such a cutting process. The cutting apparatus shown in FIG. 10 differs from that shown in FIG. 2 only in that two cutting units 45a and 45b are provided.

  A cutting blade 47 having a thickness of 200 to 300 μm is attached to the cutting unit 45a, and a cutting blade 47 having a thickness of 20 to 30μ is attached to the cutting unit 45b. The cutting depth of the cutting blade 47 of the cutting unit 45a is a depth that does not reach the device region 1a, and the cutting depth of the cutting unit 45b is a depth that reaches the protective seal 5. Then, after the machining groove 8a (8b) shown in FIG. 9a is formed by the cutting blade 47 of the cutting unit 45a, the chuck table 42 is continuously fed, so that the machining groove 9a (9b) is obtained by the cutting blade 47 of the cutting unit 45b. Will continue to be formed. In such an embodiment, since the two machining grooves 8a (8b) and 9a (9b) can be formed by one feed of the chuck table 42, the machining efficiency is high.

BRIEF DESCRIPTION OF THE DRAWINGS The wafer processed in embodiment of this invention is shown, (a) is a perspective view, (b) is a side view. It is a perspective view of the cutting device used in the embodiment of the present invention. It is sectional drawing which shows the cutting blade of the cutting device used in embodiment. It is a figure which shows the grinding processing apparatus used by embodiment, Comprising: (a) is a perspective view, (b) is a side view. It is a figure which shows the wafer which performed the concave shape, Comprising: (a) is a perspective view, (b) is a sectional side view. 1A and 1B show a wafer obtained by processing a street recognition groove, where FIG. 1A is a plan view and FIG. 1B is a perspective view. It is a figure which shows the wafer which performed the concave shape, Comprising: (a) is a top view, (b) is a perspective view. It is a figure which shows the wafer which performed the reinforcement part cutting process, Comprising: (a) is a top view, (b) is a perspective view. It is a figure which shows the wafer which performed the device area | region cutting process, Comprising: (a) is a perspective view, (b) is a side view. It is a perspective view of the cutting device used in the example of a change of the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wafer, 1a ... Device area | region, 1b ... Reinforcement part,
2a, 2b ... street, 3 ... semiconductor chip (device),
5 ... Protective seal, 7a, 7b ... Street recognition groove,
8a, 8b, 9a, 9b ... processing groove, 10 ... cutting device, 44 ... infrared camera,
45 ... cutting unit, 47 ... cutting blade.

Claims (6)

A wafer having a device region formed by dividing a plurality of devices on a surface by a street in a first direction and a street in a second direction, and an outer peripheral surplus region surrounding the device region, is provided as an individual device. A method of dividing a wafer to be divided,
A street recognition groove forming a street recognition groove in the surplus area of the back surface of the wafer corresponding to the street in the first direction and the street in the second direction by adsorbing the front surface of the wafer and seeing through the wafer from the back side. Forming process;
A concave processing step of grinding a back surface corresponding to the device region to form a ring-shaped reinforcing portion in the outer peripheral surplus region;
A metal film coating process for coating the back surface of the wafer with a metal film;
The front surface of the wafer is attracted to detect the street recognition groove from the back surface of the wafer, and the wafer is cut along the street in the first direction and the street in the second direction based on the position of the street recognition groove. A wafer dividing method comprising: a wafer cutting step.   2. The wafer dividing method according to claim 1, wherein the street recognition groove forming step is performed after the concave processing step, and then the metal film coating step is performed.   2. The wafer according to claim 1, wherein, after the street recognition groove forming step, the concave processing step is performed so as to leave the street recognition groove in the outer peripheral surplus region, and then the metal film coating step is performed. How to split.   The wafer cutting step includes a first cutting step of cutting the reinforcing portion along a street in the first direction and a street in the second direction at a depth not reaching the device region from the back surface of the wafer; A wafer that is thinner than the cutting blade used in the first cutting step is used to completely cut the wafer along the groove of the reinforcing portion formed in the first cutting step and divide the wafer into individual devices. The wafer dividing method according to any one of claims 1 to 3, further comprising:   6. The wafer dividing method according to claim 5, wherein the second cutting step is performed after all the first cutting steps are completed.   6. The wafer dividing method according to claim 5, wherein a cutting device having two rotating cutting blades is used, and the first cutting step and the second cutting step are performed by the two cutting blades. .

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