JP2017050319A - Dicing method and dicing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing method and a dicing device, which can prevent flaws on a semiconductor element caused by scattered corner chips.SOLUTION: A semiconductor device manufacturing method has: a dicing process S1 of forming on a surface Wa of a wafer W where a semiconductor element SD is formed, a cutting groove 52 which is a cutting groove 52 along a dicing line DL and which does not pierce the wafer W to a rear face Wb; an attachment process S2 of attaching a BG tape 66 to the surface Wa of the wafer W; and a back grinding process S3 of performing cutting work on the rear face Wb of the wafer W until reaching the cutting groove 52 to separate the wafer W into individual semiconductor elements SD. In the dicing process S1, the cutting groove 52 is formed at a portion of an outer edge of the wafer W except a beveled part R.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a dicing method and a dicing apparatus, and more particularly to a dicing method and a dicing apparatus for forming a groove shallower than the thickness of the wafer on the surface of the wafer.

  A wafer on which a plurality of semiconductor elements are formed is subjected to cutting such as cutting or grooving by a dicing apparatus. The dicing machine includes a thin disk-shaped blade that is rotated at high speed by a spindle and a table that sucks and holds the wafer. The wafer is sucked and held on the table, and the wafer is formed in a lattice pattern by the blade that rotates at high speed. Cut along the dicing line. The blade and the table are relatively moved by respective moving portions in the X, Y, Z, and θ directions provided in the dicing apparatus. Thus, the wafer is cut along the dicing line.

  Patent Document 1 discloses a semiconductor device manufacturing method in which a plurality of semiconductor elements are separated from a wafer, and a semiconductor device manufacturing method to which a dicing method called a DBG method (Dicing Before Grinding) is applied is disclosed. Yes.

  The DBG method includes a dicing step, a pasting step, and a back surface grinding (back grinding) step.

  In the DBG method dicing process, as shown in the cross-sectional view of the wafer W in FIG. 12A, the surface of the wafer W is cut by the blade 1 and has a depth that does not penetrate the back surface of the wafer W, that is, the wafer W The cutting groove 2 for separation which is shallower than the thickness of is formed. As a result, as shown in the plan view of the wafer W in FIG. 13, lattice-shaped cutting grooves 2 along the dicing lines are formed on the surface of the wafer W.

  Next, in the attaching step, the wafer W is turned upside down as shown in FIG. 12B, and the back grinding tape (protective tape, hereinafter) is placed on the surface of the semiconductor element SD (Semiconductor Device) on the lower side in the figure. , Referred to as BG tape) 3 is attached.

  Next, in the back surface grinding step, as shown in FIG. 12C, the back surface of the wafer W which is the upper surface in the drawing is subjected to back surface grinding by the back grinder 4 until it reaches the cutting groove 2, and each wafer W is individually processed. The semiconductor element SD is separated.

  Thereafter, a wafer holding tape (not shown) is attached to the back surface of the separated semiconductor element SD, then the BG tape 3 is removed, and the semiconductor element SD is taken out from the wafer holding tape.

JP 2002-100588 A

  By the way, in the manufacturing method of a semiconductor device like patent document 1, the following problems generate | occur | produce in a back surface grinding process.

  That is, as shown in FIG. 13, a plurality of small-shaped odd-shaped chips (hereinafter referred to as corner chips) CT existing on the outer edge WA of the wafer W are scattered during the back surface grinding process, and the scattered corner chips CT are converted into the semiconductor element SD. Between the back surface of the semiconductor element SD and the back grinder 4 (see FIG. 12C), and the back surface of the semiconductor element SD is damaged by the sandwiched corner chip CT. Further, there is a problem that the semiconductor element SD becomes a defective product depending on the degree of scratches. The corner chip CT is a chip in a region where the semiconductor element SD cannot be formed due to the size and shape, and the shape and size are various.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a dicing method and a dicing apparatus that can prevent the semiconductor element from being damaged due to scattered corner chips.

  The inventor of the present application has verified the cause of the scattering of the corner chips CT in the back grinding process, and has found a new dicing method and dicing apparatus that achieve the object of the present invention.

  The cutting grooves 2 formed on the surface of the wafer W in the conventional dicing process are formed at a uniform depth on the surface of the wafer W. That is, the cutting groove 2 in FIG. 13 is formed through the outer edge portion WA of the wafer W. When back grinding is performed on the wafer W having such a form until the cutting groove 2 is reached, the corner chip CT present on the outer edge WA of the wafer W is also separated together with the semiconductor element SD. Then, it was experimentally confirmed that the separated corner chips CT were scattered and sandwiched between the back surface of the semiconductor element SD and the back grinder 4 to scratch the back surface of the semiconductor element SD.

  Therefore, in one aspect of the dicing method of the present invention, in order to achieve the object of the present invention, a plurality of semiconductor elements formed on the front surface of the wafer are partitioned before the back surface grinding process for grinding the back surface of the wafer is performed. A dicing method in which a groove is ground from the surface side of a wafer along a dicing line to be cut toward a cutting start position located inside from one outer edge of the wafer where one end of the dicing line is located, The blade advances from the front side of the wafer to a depth position where a groove shallower than the thickness of the wafer is cut and the cutting start position is cut by the blade, and the other end of the wafer where the other end of the dicing line is located Cutting the wafer and blade relatively along the dicing line from the outer edge of the wafer toward the inner cutting end position By moving to comprise a groove processing step of cutting a groove by a blade from the cutting start position to the cutting end position, the blade is moved to the cutting end position, and the blade retracting step for retracting from the surface side of the wafer, the.

  Further, according to one aspect of the dicing apparatus of the present invention, in order to achieve the object of the present invention, a plurality of semiconductor elements formed on the front surface of the wafer are partitioned before the back surface grinding process for grinding the back surface of the wafer is performed. A dicing apparatus that grinds grooves from the surface side of a wafer along a dicing line to be moved, a table that holds the wafer, a blade that is rotated by a spindle, and a blade that moves forward and backward with respect to the surface of the wafer. A means for moving the means, the table and the blade relatively in the cutting direction along the dicing line, and a control means for controlling the blade advance / retreat means and the move means, by controlling the blade advance / retreat means, At the cutting start position located inside from one outer edge of the wafer where one end of the dicing line is located Therefore, the outer edge of the wafer on which the other end of the dicing line is located is controlled by moving the blade from the front side of the wafer to a depth position where a groove shallower than the thickness of the wafer is cut and controlling the moving means. By moving the wafer and the blade relatively in the cutting direction toward the cutting end position located inside from the part, the groove is cut from the cutting start position to the cutting end position by the blade, and the blade advance / retreat means is controlled. And a control means for retracting the blade moved to the cutting end position from the surface side of the wafer.

  According to one aspect of the present invention, the groove formed in the dicing line is from the cutting start position to the cutting end position, and the dicing line on the inner side from the outer edge of the wafer is the uncut area. That is, a groove was formed so as not to penetrate the outer edge of the wafer. When grinding is performed until the groove reaches the wafer in such a form, the semiconductor element is separated from the wafer, but the plurality of corner chips present on the outer edge of the wafer are not separated, and the outer edge of the wafer is not separated. It is left connected along. Thereby, the damage of the back surface of a semiconductor element resulting from the separated corner chip can be prevented. Further, since the groove does not penetrate the outer edge portion of the wafer, sludge does not enter the inside of the wafer through the groove. Thereby, it is possible to prevent a large amount of sludge from adhering to the semiconductor element.

  Further, one aspect of the dicing method of the present invention includes an index feeding step of moving the wafer and the blade relative to each other by the pitch of the dicing line in the index feeding direction orthogonal to the cutting direction after the blade retracting step. It is preferable to repeat the process, the groove processing process, and the blade retracting process by the number of dicing lines.

  According to one embodiment of the present invention, grooves can be sequentially formed in a plurality of dicing lines.

  In one aspect of the dicing method of the present invention, the length from one outer edge portion of the wafer to the cutting start position and the length from the other outer edge portion of the wafer to the cutting end position are formed on the surface of the outer peripheral portion of the wafer. It is preferable to set the length based on the length of the chamfered portion, the radius of the blade, and the depth of the groove.

  According to one aspect of the dicing apparatus of the present invention, the control means determines the length from one outer edge of the wafer to the cutting start position and the length from the other outer edge of the wafer to the cutting end position. Set based on the length of the chamfered portion formed on the surface of the blade, the radius of the blade, the depth of the groove, the length to the cutting start position, the length to the cutting end position, the speed in the cutting direction by the moving means, It is preferable to control the blade advancing / retreating means and the moving means based on the radius of the blade and the depth of the groove.

  According to one aspect of the present invention, a chamfered portion is formed on the outer peripheral portion of the wafer, and the chamfered portion is formed from the outer peripheral portion to the front surface and the back surface of the wafer. The length of the chamfered portion formed on the surface of the wafer among the chamfered portions is the length of the uncut region. Thereby, since a chamfering part turns into an uncut area | region, the corner chip after a back surface grinding process can be left in the state connected with the ring-shaped chamfering part. Moreover, since no semiconductor element is formed in the chamfered portion, the semiconductor element is separated without any problem.

  According to the dicing method and the dicing apparatus of the present invention, it is possible to prevent the semiconductor element from being damaged due to scattered corner chips.

External view of dicing apparatus according to the present invention Top view of wafer The perspective view which showed the structure of the process part of the dicing apparatus of FIG. Explanatory drawing which showed the grinding method of the grinding groove by the 1st dicing method Plan view of wafer with grinding grooves formed by first dicing method Side view showing the outline of the back grinding machine that performs the back grinding process A flowchart showing a method of manufacturing a first semiconductor device Explanatory drawing which showed operation | movement of each process of the manufacturing method of FIG. Explanatory drawing which showed the dicing method of 2nd Embodiment. Explanatory drawing which showed the dicing method of another form The top view of the wafer in which the 1st and 2nd grinding groove was formed by the dicing method of FIG. Explanatory drawing showing a conventional semiconductor device manufacturing method in time series Plan view of wafer with cut grooves formed by conventional dicing process

  Hereinafter, preferred embodiments of a dicing method and a dicing apparatus according to the present invention will be described with reference to the accompanying drawings.

[Configuration of Dicing Device 10]
FIG. 1 is an external view of a dicing apparatus 10 that performs a dicing process by a dicing method according to the present invention.

  The dicing apparatus 10 includes a load port 12 for transferring a cassette in which a plurality of disc-shaped wafers W are stored to an external apparatus, and a suction pad 14. The dicing apparatus 10 conveys the wafer W to each part of the apparatus. And a table 18 for sucking and holding the wafer W, a processing unit 20 for dicing the surface of the wafer W, and a spinner 22 for cleaning and drying the wafer W after the dicing. The operation of each part of the dicing apparatus 10 is controlled by a controller 24 which is a control means.

<Processing part 20>
The processing unit 20 is provided with a camera 26. This camera 26 images a lattice-shaped dicing line DL (Dicing Line) formed on the surface Wa of the wafer W as shown in the plan view of the wafer W shown in FIG. Is used as a member for alignment. A plurality of semiconductor elements SD are formed in a rectangular region defined by the dicing line DL of the wafer W. A cutting groove (groove) shallower than the thickness of the wafer W is formed in these dicing lines DL by a blade 28 (see FIG. 1) described later.

  Returning to FIG. 1, a pair of disk-shaped blades 28 arranged opposite to each other and a spindle 32 with a built-in high-frequency motor that rotates the blades 28 are provided inside the processing unit 20.

  FIG. 3 is a perspective view illustrating a configuration of the processing unit 20.

  The spindle 32 is attached to a Z direction moving part (blade advance / retreat means) 34. The spindle 32 includes an X-direction moving unit (moving unit) 36 that moves the table 18 in the cutting direction along the dicing line DL, and a Y-direction moving unit 38 that moves the blade 28 in the index feed direction orthogonal to the cutting direction. It is relatively moved along the surface of the wafer W.

  The X-direction moving unit 36 includes a rail 40 extending in the X direction, and a table support member 42 is slidably mounted on the rail 40 in the X direction. The X-direction moving unit 36 includes a drive unit (not shown) that moves the table support member 42 in the X direction along the rail 40.

  The Y-direction moving unit 38 is installed on the portal base 21 and includes a rail 44 extending in the Y direction. A slider 46 is supported on the rail 44 so as to be slidable in the Y direction. The Y-direction moving unit 38 includes a drive unit (not shown) that moves the slider 46 along the rail 44 in the Y direction.

  The slider 46 includes a rail 48 extending in the Z direction, and a slider 50 of the Z direction moving unit 34 is supported on the rail 48 so as to be slidable in the Z direction. The Z-direction moving unit 34 includes a drive unit (not shown) that moves the slider 50 in the Z direction along the rail 48. Thereby, the blade 28 is moved back and forth with respect to the surface of the wafer W.

  The blade 28 is rotated at a high speed of 6000 rpm to 80000 rpm by the spindle 32, and the Y direction moving unit 38 performs Y-direction index feeding independent of each other, and the Z-direction moving unit 34 performs Z-direction cutting feeding. Further, the table 18 that holds the wafer W by suction is configured to be fed in the X direction by the X direction moving unit 36 and rotated in the θ direction by a θ rotation mechanism unit (not shown). By these operations in the X, Y, Z, and θ directions, the cutting edge of the outer peripheral portion of the blade 28 that rotates at high speed comes into contact with the dicing line DL (see FIG. 2) of the wafer W, and a cutting groove is formed along the dicing line DL. It is formed.

  As the blade 28, a metal resin bond blade in which diamond abrasive grains or CBN abrasive grains are electrodeposited with nickel, or a resin mixed with metal powder is used.

<Schematic action of dicing apparatus 10>
In the dicing apparatus 10 of FIG. 1, first, a cassette storing a plurality of wafers W is placed on the load port 12 by a transfer device (not shown) or manually. The wafer W is taken out from the placed cassette and placed on the surface of the table 18 by the transfer device 16. Thereafter, the back surface of the wafer W is sucked and held on the table 18. As a result, the wafer W is held on the table 18.

  The surface of the wafer W held on the table 18 is imaged by the camera 26, and the position of the dicing line DL formed on the surface of the wafer W and the position of the blade 28 are moved in the X, Y, and θ directions. 36 and 38 are adjusted by adjusting the posture of the table 18. Thereby, the dicing line DL forming the cutting groove is aligned with the lower position of the blade 28 and aligned in the X direction.

  When alignment is completed and dicing is started, the spindle 32 discloses rotation, the blade 28 rotates at a high speed, and cutting fluid is supplied from a nozzle (not shown) to the machining point. In this state, the wafer W is cut and fed in the X direction together with the table 18 by the X direction moving unit 36. Then, the blade 28 is lowered in the Z direction from the retracted position to the depth position where the cutting groove is cut by the Z direction moving portion 34. As a result, the grinding grooves are ground in the dicing line DL of the wafer W.

  The feed amounts and feed speeds in the X, Y, and Z directions in the processing unit 20 are set by the controller 24 that controls the moving units 34, 36, and 38 in the X, Y, and Z directions.

<Dicing Method of First Embodiment>
4A and 4B are explanatory views showing, in a time series, the first dicing method of the cutting groove 52 formed along the dicing line DL on the surface Wa of the wafer W. FIG.

  As shown in FIG. 4, the controller 24 operates in the Z direction so that the cutting depth a of the cutting groove 52 along the dicing line DL is shallower than the thickness t of the wafer W and does not penetrate the back surface Wb of the wafer W. The feed amount of the blade 28 in the Z direction by the moving unit 34 is controlled.

  Further, the controller 24 controls the movement of the blade 28 relative to the wafer W by the Z-direction moving unit 34 so that the cutting groove 52 is formed in a portion excluding the outer edge portion of the wafer W. In this case, it is assumed that the feeding speed of the wafer W by the X direction moving unit 36 is controlled to a constant speed by the controller 24.

  Here, the outer edge portion of the wafer W refers to a portion including the chamfered portion R formed on the surface Wa of the outer edge portion of the wafer W. In the embodiment, the dicing line DL formed in the chamfered portion R, that is, the dicing line DL having the length b of the chamfered portion R formed on the surface Wa of the outer edge portion of the wafer W is not ground, and the length b Only the dicing line DL formed inside the wafer W except the dicing line DL is ground by the blade 28.

In other words, the controller 24 has a chamfered portion based on the outer diameter of the wafer W, the length b of the chamfered portion R, and the length information of each dicing line DL stored in the product type information of the wafer W inputted in advance to the controller 24. Based on the length b of R, the radius r of the blade 28, and the depth a, the position of the length C1 is set as the cutting start position. The length C1 is a length obtained by adding the length b and the length h, and the length h is obtained by an equation of r ² = h ² + (r−a) ² .

  Then, the controller 24 controls the Z-direction moving unit 34 based on the length C1, the speed in the cutting direction by the X-direction moving unit 36, the radius r of the blade 28, and the cutting depth a of the blade 28 with respect to the wafer W. .

  Specifically, the controller 24 advances the blade 28 from the retracted position toward the cutting start position located at the length C1 from one outer edge portion of the wafer W where one end portion of the dicing line DL is located. Then, the blade 28 located at the cutting end position located at the length C1 is retreated toward the retreat position from the other outer edge portion of the wafer W where the other end portion of the dicing line DL is located.

  Thereby, as shown in the plan view of the wafer W in FIG. 5, the cutting groove 52 in each dicing line DL is formed in a portion excluding the length b of the chamfered portion R of the wafer W.

[Configuration of Back Grinding Device 60]
FIG. 6 is a side view showing an outline of the back surface grinding device 60 that executes the back surface grinding process.

  The back grinding device 60 includes a table 62 and a back grinder 64.

  With the dicing apparatus 10 (see FIG. 1), the BG tape 66 is attached to the entire surface Wa of the wafer W in which the cutting grooves 52 are formed in the dicing line DL, and all the semiconductor elements SD are protected. The BG tape 66 is made of a base material such as PET or polyolefin and an adhesive such as an acrylic synthetic resin, and the adhesive is in close contact with the semiconductor element. The pressure-sensitive adhesive has a characteristic that the bonding state in the resin is changed by irradiation with ultraviolet rays and the adhesive force is lowered.

  The wafer W is transferred to the back surface grinding device 60 and is sucked and held on the upper surface of the table 62 via the BG tape 66. The table 62 is rotated at a predetermined rotation speed around the rotation shaft 68.

  The back grinder 64 is provided above the table 62. A plurality of grindstones (not shown) are fixed to the lower surface of the main body 70 of the back grinder 64 at a predetermined interval, and these grindstones are lowered together with the main body 70 toward the table 62. Thereby, the grindstone is pressed against the back surface Wb of the wafer W, and the back surface Wb is ground. Then, the back surface Wb is ground until the grindstone reaches the cutting groove 52, and the grinding process ends when the grindstone reaches the cutting groove 52. Thereby, the plurality of semiconductor elements SD are separated for each semiconductor element SD. Further, the main body 70 is rotated at a predetermined rotation speed around the rotation shaft 72. The rotating shaft 72 is arranged at a position eccentric with respect to the rotating shaft 68.

[Method of Manufacturing Semiconductor Device]
Hereinafter, a method for manufacturing a semiconductor device using the dicing apparatus 10 and the back grinding apparatus 60 will be described.

<First manufacturing method>
FIG. 7 is a flowchart showing a first method for manufacturing a semiconductor device. FIG. 8 is an explanatory diagram showing the operation of each step based on the flowchart of FIG.

  The dicing step S1 in FIG. 7 is performed by the Z direction moving unit 34, the X direction moving unit 36, and the Y direction moving unit 38 controlled by the controller 24 shown in FIG.

  In the dicing step S1 of FIG. 7, the wafer W is sucked and held on the upper surface of the table 18 with the semiconductor element SD facing up, as shown in FIG. 8A. Then, the dicing line DL is cut by dicing with the blade 28 to form a cutting groove 52 on the surface side of the wafer W.

  In the dicing step S1, as shown in FIG. 4, the cutting of the groove 52 by the blade 28 is started from the cutting start position located at one length C1, and the groove is reached to the cutting end position located at the other length C1. 52 cutting is performed.

  Specifically, first, from one outer edge portion of the wafer W where one end portion of the dicing line DL formed on the surface Wa of the wafer W is located toward the cutting start position located at the length C1, the wafer The blade 28 retracted from the surface Wa side of W is advanced to the depth position where the groove 52 is cut into the dicing line DL by the Z-direction moving unit 34, and the cutting start position is cut by the blade 28 (blade advancement process).

  Next, the wafer W is moved in the cutting direction from the other outer edge portion of the wafer W where the other end portion of the dicing line DL is positioned toward the cutting end position located at the length C1, thereby cutting start position. The groove 52 is cut by the blade 28 from the cutting end position to the cutting end position (grooving step).

  Then, the blade 28 moved to the cutting end position is retracted from the surface Wa side of the wafer W by the Z-direction moving unit 34 (blade retracting step).

  Thereby, the cutting groove 52 in the dicing line DL is formed in a portion excluding the length b of the chamfered portion R of the wafer W.

  Next, after the blade retracting process, the wafer W and the blade 28 are relatively moved by the pitch of the dicing line DL in the index feeding direction perpendicular to the cutting direction (index feeding process). This movement is performed by moving the blade 28 in the Y direction by the Y direction moving unit 38.

  Then, after the index feeding process is completed, the blade advancement process, the groove machining process, and the blade retracting process are repeated for the number of dicing lines DL formed in the same direction. Thereafter, after the wafer W is rotated by 90 degrees by the table 18, the same groove processing is performed on all the dicing lines DL orthogonal to the previously performed dicing lines DL. The dicing process is thus completed.

  Next, in the attaching step S2 of FIG. 7, the BG tape 66 is attached to the entire surface Wa of the wafer W as shown in FIG. 8B.

  Next, in the back surface grinding step S3, as shown in FIG. 8C, the wafer W is sucked and held on the table 62 of the back surface grinding device 60 with the back surface Wb facing up, and the table 62 and the back grinder 64 are rotated. Then, grinding of the back surface Wb of the wafer W is started.

  The back surface Wb is ground until the grindstone of the back grinder 64 reaches the cutting groove 52, and the grinding process ends when the grindstone reaches the cutting groove 52.

<Effect of the first manufacturing method>
When the back grinding step S3 is completed, the plurality of semiconductor elements SD are separated for each semiconductor element SD. However, the cutting groove 52 is not formed in the dicing line DL of the chamfered portion R of the wafer W. For this reason, the plurality of corner chips CT present in the chamfered portion R are not separated and remain in a state of being connected along the outer edge portion of the wafer W.

  Thereby, according to the 1st manufacturing method, the damage | wound on the back surface of the semiconductor element SD resulting from the scattered corner chip CT can be prevented. Further, since the cutting groove 52 does not penetrate the outer edge portion of the wafer W, sludge does not enter the inside of the wafer W through the cutting groove 52. Thereby, it is possible to prevent a large amount of sludge from adhering to the semiconductor element SD.

<Dicing Method of Second Embodiment>
In the dicing method of the first embodiment, as shown in FIG. 4, the entire area of the chamfered portion R having the length b is set as an uncut area, but an uncut area remains in a part of the area of the length b. Alternatively, the cutting start position and the cutting end position may be set. This dicing method will be described as a second dicing method.

  FIGS. 9A and 9B are explanatory diagrams showing the second dicing method in time series.

  As shown in FIG. 9, a position where an uncut region having a length d remains in a part of a region having a length b is set, and the position is calculated based on the length d, the radius r and the depth a of the blade 28. The position of the length C2 may be set as a cutting start position and a cutting end position. Thereby, even if it is the wafer W shown in FIG. 9, the effect similar to the wafer W shown in FIG. 4 can be acquired. In other words, even after the back grinding process is completed, an uncut region having a length d remains in a part of the region having a length b, so that the plurality of corner chips CT are not separated and are formed on the outer edge of the wafer W. It is left connected along.

  As a result, according to the second dicing method, it is possible to prevent the back surface of the semiconductor element SD from being damaged due to the scattered corner chip CT. Further, since the cutting groove 52 does not penetrate the outer edge portion of the wafer W, sludge does not enter the inside of the wafer W through the cutting groove 52. Thereby, it is possible to prevent a large amount of sludge from adhering to the semiconductor element SD.

<Other dicing methods>
FIGS. 10A, 10B, and 10C are explanatory views showing a grinding method for grinding the first grinding groove and the second cutting groove 56 in the dicing line DL in time series.

  As shown in FIG. 10, the controller 24 has a Z-direction moving unit 34 such that the cutting depth a of the first cutting groove 54 is shallower than the thickness t of the wafer W and does not penetrate the back surface Wb of the wafer W. The feed amount in the Z direction of the blade 28 is controlled.

  Further, the controller 24 is a second cutting groove 56 on both sides formed continuously with the first cutting groove 54, and the depth e of the second cutting groove 56 formed on the outer edge portion of the wafer W. However, the feed amount in the Z direction of the blade 28 by the Z direction moving part 34 is controlled so as to be shallower than the depth a of the first cutting groove 54. In this case, it is assumed that the feed rate by the X-direction moving unit 36 is controlled to be constant.

  Here, the outer edge portion of the wafer W refers to a portion including the chamfered portion R provided on the outer edge portion of the wafer W. In the embodiment, the second cutting groove 56 is formed in the dicing line DL formed at the position of the length b of the chamfered portion R, and the dicing line DL formed inside the wafer W excluding the region of the length b. A first cutting groove 54 is formed.

  That is, the controller 24 is positioned at a certain distance outside from one outer edge of the wafer W in the dicing line DL, and the height position of the blade 28 for forming the second cutting groove 56 having the cutting depth e. Is set to the first cutting start position.

  The controller 24 determines the height position of the blade 28 for forming the first cutting groove 54 having the cutting depth a based on the length b, the speed in the cutting direction, and the radius r of the blade 28. Is set to the cutting start position (see FIG. 10B).

  Further, the controller 24 forms a second cutting groove 56 having a cutting depth e on the other outer edge portion of the wafer W based on the length b, the speed in the cutting direction, and the radius r of the blade 28. The height position of the blade 28 is set to the third cutting start position.

  Further, the controller 24 sets a position outside the other outer edge of the wafer W as a cutting end position.

  Accordingly, as shown in the plan view of the wafer W in FIG. 11, the second cutting groove 56 having a depth e is formed in the dicing line DL of the chamfered portion R of the wafer W, and the dicing line of the portion excluding the chamfered portion R is formed. A first cutting groove 54 having a depth a is formed in the DL.

  As shown in FIG. 10C, an arc-shaped grinding groove 55 to which the outer peripheral shape of the blade 28 is transferred is formed between the cutting groove 54 and the cutting grooves 56 on both sides.

<Manufacturing method of semiconductor device to which other dicing method is applied>
In the dicing process, the wafer W is sucked and held on the upper surface of the table 18 of the dicing apparatus 10 of FIG. 1 with the semiconductor element SD facing up. Then, the cutting grooves 54 and 56 are formed in the dicing line DL by dicing with the blade 28.

  In the dicing process, as shown in FIG. 10C, the cutting depth a of the first cutting groove 54 is shallower than the thickness t of the wafer W and does not penetrate the back surface Wb of the wafer W. It is formed. Further, the depth e of the second cutting groove 56 formed on the outer edge portion of the wafer W, which is the second cutting groove 56 on both sides formed continuously with the first cutting groove 54, is the first. The cutting groove 54 is formed to be shallower than the depth a.

  Next, in the attaching step, the BG tape 66 is attached to the entire surface Wa of the wafer W.

  Next, in the back surface grinding process, the wafer W is sucked and held on the table 62 of the back surface grinding device 60 with the back surface Wb facing up, and the table 62 and the back grinder 64 are rotated to grind the back surface Wb of the wafer W. Start.

  The back surface Wb is ground until the grindstone of the back grinder 64 reaches the cutting groove 54. When the grindstone reaches the cutting groove 54, the grinding process is finished.

<Effects of other dicing methods>
When the back grinding process is finished, the plurality of semiconductor elements SD are separated for each semiconductor element SD. However, since the depth e of the second cutting groove 56 is shallower than the depth a of the first cutting groove 54, the plurality of corner chips CT present at the outer edge of the wafer W are not separated, and the wafer W It remains in a state of being connected along the outer edge.

  Thereby, it is possible to prevent the back surface of the semiconductor element SD from being damaged due to the scattered corner chips CT. Further, although the second cutting groove 56 penetrates the outer edge portion of the wafer W, the opening portions at both ends of the second cutting groove 56 are opened more than the opening portions at both ends of the first cutting groove 54. Since the area is small, the amount of sludge that enters the inside of the wafer W can be reduced. Thereby, it is possible to prevent a large amount of sludge from adhering to the semiconductor element SD.

  W ... Wafer, 10 ... Dicing machine, 12 ... Load port, 14 ... Suction pad, 16 ... Transport device, 18 ... Table, 20 ... Processing part, 22 ... Spinner, 24 ... Controller, 26 ... Camera, 28 ... Blade, 32 ... Spindle, 34 ... Z direction moving part, 36 ... X direction moving part, 38 ... Y direction moving part, 40 ... Rail, 42 ... Table support member, 44 ... Rail, 46 ... Slider, 48 ... Rail, 50 ... Slider, 52 ... Cutting groove, 54 ... Cutting groove, 55 ... Grinding groove, 56 ... Cutting groove, 60 ... Back grinding device, 62 ... Table, 64 ... Back grinder, 66 ... BG tape, 68 ... Rotating shaft, 70 ... Main body, 72 …Axis of rotation

Claims (5)

A dicing method in which grooves are ground from the front surface side of the wafer along a dicing line that partitions a plurality of semiconductor elements formed on the front surface of the wafer before the back surface grinding process for grinding the back surface of the wafer is performed. And
The blade is cut from the front side of the wafer and the groove shallower than the thickness of the wafer toward the cutting start position located inside from one outer edge of the wafer where one end of the dicing line is located. A blade advancement step of advancing to a depth position and cutting the cutting start position with the blade;
The wafer and the blade are relatively moved in the cutting direction along the dicing line toward the cutting end position located inside from the other outer edge of the wafer where the other end of the dicing line is located. A groove processing step of cutting the groove with the blade from the cutting start position to the cutting end position,
A blade retracting step for retracting the blade moved to the cutting end position from the surface side of the wafer;
Including a dicing method. After the blade retracting step, there is an index feeding step in which the wafer and the blade are relatively moved in an index feeding direction orthogonal to the cutting direction by the pitch of the dicing line,
The dicing method according to claim 1, wherein the blade advancement step, the groove processing step, and the blade retracting step are repeated by the number of the dicing lines.   The length from one outer edge portion of the wafer to the cutting start position, and the length from the other outer edge portion of the wafer to the cutting end position is a chamfered portion formed on the surface of the outer peripheral portion of the wafer. The dicing method according to claim 1, wherein the dicing method is set based on a length, a radius of the blade, and a depth of the groove. A dicing apparatus that grinds grooves from the front surface side of the wafer along a dicing line that partitions a plurality of semiconductor elements formed on the front surface of the wafer before the back surface grinding process for grinding the back surface of the wafer is performed. And
A table for holding the wafer;
A blade rotated by a spindle;
Blade advancing and retracting means for moving the blade forward and backward with respect to the surface of the wafer;
Moving means for moving the table and the blade relatively in the cutting direction along the dicing line;
Control means for controlling the blade advancement / retraction means and the movement means, wherein the blade advancement / retraction means is controlled so that one end of the dicing line is positioned inward from one outer edge of the wafer. By moving the blade from the front surface side of the wafer to a depth position where the groove shallower than the thickness of the wafer is cut and controlling the moving means toward the cutting start position. By moving the wafer and the blade relatively in the cutting direction from the other outer edge of the wafer where the end of the wafer is located toward the cutting end position located inside, the cutting start position allows the The groove is cut by the blade to a cutting end position, and the blade advancing / retreating means is controlled, whereby the cutting is performed. Said blade has moved to completion position, and control means for retracting from the surface side of the wafer,
A dicing apparatus. The control means includes
The length from one outer edge of the wafer to the cutting start position, and the length from the other outer edge of the wafer to the cutting end position are chamfered portions formed on the surface of the outer edge of the wafer. Set based on the length, the radius of the blade, the depth of the groove, the length to the cutting start position, the length to the cutting end position, the speed in the cutting direction by the moving means, The dicing apparatus according to claim 4, wherein the blade advancing / retreating unit and the moving unit are controlled based on a radius of the blade and a depth of the groove.

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