JP2017028160A - Machining method for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide wafer level chip-size package devices excellent in quality.SOLUTION: In a machining method for semiconductor wafers 2 having devices comprising electrode bumps 23 formed on surfaces thereof, package devices, whose outer peripheries are coated with a mold resin, are produced in steps of: adhering protective members to the surfaces of the wafers 2 and grinding backsides of the wafers, so as to form the wafers with a finishing thickness of devices; attaching substrates with rigidity to the backsides of the wafers and peeling off the protective members adhered to the surfaces of the wafers, and firstly cutting out the surface sides of the wafers along a division scheduled line with a cutting blade 623 having a first thickness, so as to divide the wafers into individual devices; laying a mold resin 70 on the surfaces of the divided wafers and burying the mold resin in divided grooves 210; and cutting a center part in a width direction of the mold resin buried in the divided grooves along the divided groves.SELECTED DRAWING: Figure 13

Description

  In the present invention, a wafer in which a plurality of division lines are formed in a lattice shape on the surface and a device is formed in a plurality of regions partitioned by the plurality of division lines is divided into individual lines along the division lines. The present invention relates to a wafer processing method in which a device is divided and each device is coated with a resin.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by division lines arranged in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and devices such as ICs and LSIs are formed in the partitioned regions. . By cutting the semiconductor wafer formed in this way along the planned dividing line, the region where the device is formed is divided to manufacture individual devices.

  In recent years, a packaging technique for dividing a wafer into individual devices and coating the individual devices with a resin has been developed. A package technology called a wafer level chip size package (WLCSP), which is one of the package technologies, is disclosed in Patent Document 1 below.

  The packaging technology disclosed in Patent Document 1 below covers a resin on the back surface of a wafer, forms a cutting groove that reaches the resin along a planned dividing line from the surface of the wafer, and lays a mold resin on the surface of the wafer. After coating each device and embedding the mold resin in the cutting groove, the mold resin filled in the cutting groove is cut by a cutting blade having a thickness smaller than the width of the cutting groove, thereby obtaining individual wafer level chip size packages (WLCSP). ) Is divided into package devices called.

Further, the following technology has been developed as a wafer processing method for manufacturing a package device called a wafer level chip size package (WLCSP).
(1) A cutting groove having a depth corresponding to the finished thickness of the device is formed along the planned dividing line from the front surface side of the wafer.
(2) The mold resin is laid on the surface of the wafer and the mold resin is embedded in the cutting groove.
(3) A protective member is attached to the surface of the mold resin laid on the surface of the wafer, and the back surface of the wafer is ground to expose the cutting grooves.
(4) Each wafer level chip size package (WLCSP) is attached by attaching the back surface of the wafer to a dicing tape and cutting the mold resin embedded in the cutting groove with a cutting blade having a thickness smaller than the width of the cutting groove. Divide into package devices called.

JP 2006-1000053 A

In any of the processing methods described above, if a protective member is attached to the surface of the mold resin laid on the surface of the wafer and the back surface of the wafer is ground to expose the cutting groove, it corresponds to the finished thickness of the device. There is a problem in that the mold resin embedded in the deep cutting groove is crumpled to deteriorate the quality of a package device called a wafer level chip size package (WLCSP), and the grinding wheel is clogged.
Also, when the backside grinding process is performed to form the finished thickness of the device by grinding the backside of the wafer, if electrode bumps are formed on the surface of the device, even if a protective member is stuck on the surface, There is a problem that grinding marks corresponding to the electrode bumps remain on the back surface.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to obtain a package device called a wafer level chip size package (WLCSP) with good quality and to grind the back surface of the wafer. It is an object of the present invention to provide a wafer processing method in which crushing does not occur in a grinding wheel when a wafer is formed to a finished thickness of a device.

In order to solve the main technical problem, according to the present invention, a plurality of division lines are formed in a lattice pattern on the surface, and bumps are provided on the surface in a plurality of regions partitioned by the plurality of division lines. A method of processing a wafer on which a device is formed,
A protective member attaching step for attaching a protective member to the surface of the wafer;
Grinding the back surface of the wafer on which the protective member attaching step has been carried out to form the wafer in the finished thickness of the device; and
A substrate pasting step of pasting a rigid substrate on the back surface of the wafer subjected to the back grinding step and peeling off the protective member stuck on the surface of the wafer;
A division step of dividing the wafer into individual devices by cutting along the division line by a cutting blade having a first thickness from the surface side of the wafer on which the substrate pasting step has been performed to form division grooves;
A molding process in which the dividing step is performed and a molding resin is laid on the surface of the wafer divided into individual devices and the molding resin is embedded in the dividing grooves;
A package device in which the outer periphery of the device is covered with the mold resin is produced by cutting the central portion in the width direction of the mold resin embedded in the division groove formed on the wafer subjected to the molding process along the division groove. Including a mold resin cutting step.
A method for processing a wafer is provided.

In addition, according to the present invention, there is provided a wafer processing method in which a plurality of division lines are formed in a lattice shape on a surface and a device is formed in a plurality of regions partitioned by the plurality of division lines. ,
A protective member attaching step for attaching a protective member to the surface of the wafer;
Grinding the back surface of the wafer on which the protective member attaching step has been carried out to form the wafer in the finished thickness of the device; and
A substrate pasting step of pasting a rigid substrate on the back surface of the wafer subjected to the back grinding step and peeling off the protective member stuck on the surface of the wafer;
An electrode bump forming step of forming electrode bumps on the surface of the wafer on which the substrate pasting step has been performed;
A dividing step of dividing the wafer into individual devices by forming a dividing groove by cutting along a dividing line by a cutting blade having a first thickness from the surface side of the wafer;
A molding step of laying a mold resin on the surface of the wafer divided into individual devices by performing the division step and the electrode bump forming step, and embedding the mold resin in the division groove;
A package device in which the outer periphery of the device is covered with the mold resin is produced by cutting the central portion in the width direction of the mold resin embedded in the division groove formed on the wafer subjected to the molding process along the division groove. Including a mold resin cutting step.
A method for processing a wafer is provided.

In the mold resin cutting step, a central portion in the width direction of the mold resin embedded in the division groove formed in the wafer is cut along the division groove by a cutting blade having a second thickness smaller than the first thickness.
Further, in the mold resin cutting step, a laser beam thinner than the first thickness is irradiated along the dividing groove to the width direction central portion of the mold resin embedded in the dividing groove formed in the wafer, along the width direction of the mold resin. Cut the center.
After performing the above molding process, mold resin removal that removes the outer periphery of the mold resin laid on the wafer surface in an annular shape to expose the divided grooves and expose the mold resin embedded in the divided grooves to the wafer surface In the mold resin cutting step, the mold resin removal step is performed, the mold resin embedded in the division groove exposed on the outer periphery of the wafer is detected, and the width direction center of the mold resin embedded in the division groove is detected. Cut the part.
In addition, after the molding process is performed and before the mold resin cutting process is performed, a probing process is performed in which a probe needle is applied to an electrode bump formed on the surface of the device to perform an electrical test of the device.

  The wafer processing method according to the present invention includes a protective member attaching step for attaching a protective member to the surface of the wafer, and a back surface of the wafer on which the protective member attaching step has been performed to grind the wafer to the finished thickness of the device. A back surface grinding step to be formed, a substrate pasting step for pasting a rigid substrate to the back surface of the wafer on which the back surface grinding step has been performed, and peeling a protective member stuck to the front surface of the wafer; A dividing step of dividing the wafer into individual devices by cutting along a planned dividing line by a cutting blade having a first thickness from the surface side of the wafer subjected to the attaching step, and dividing the wafer into individual devices, and the dividing step Molding that lays the mold resin on the surface of the wafer divided into individual devices and embeds the mold resin in the divided grooves And a package device in which the outer periphery of the device is covered with the mold resin by cutting the central portion in the width direction of the mold resin embedded in the divided groove formed in the wafer formed with the molding process along the divided groove. Since the mold resin cutting process to be generated is included, there is no mold resin when the back surface grinding process is performed. Therefore, by performing the back surface grinding process, the mold resin embedded in the cutting groove having a depth corresponding to the finished thickness of the device causes scumming, thereby deteriorating the quality of the package device and causing the grinding wheel to be clogged. Can be prevented.

  The wafer processing method according to the present invention includes a protective member attaching step for attaching a protective member to the surface of the wafer, and grinding the back surface of the wafer on which the protective member attaching step has been performed to finish the wafer into a device. A back surface grinding step to form a thickness, a substrate pasting step of pasting a rigid substrate on the back surface of the wafer on which the back surface grinding step has been performed and peeling off a protective member attached to the surface of the wafer; An electrode bump forming step for forming an electrode bump on the surface of the wafer on which the substrate pasting step has been performed, and a dividing groove is formed by cutting along the planned dividing line from the wafer surface side with a cutting blade having a first thickness. The wafer is divided into individual devices by dividing the wafer into individual devices and performing the dividing step and the electrode bump forming step. A molding step of laying mold resin on the surface of the wafer and embedding the mold resin in the dividing groove, and a center portion in the width direction of the molding resin embedded in the dividing groove formed in the wafer on which the molding step has been performed. And a mold resin cutting step of generating a package device in which the outer periphery of the device is covered with the mold resin by cutting along the dividing groove, and no mold resin is present when performing the back surface grinding step. At the same time, there is no electrode bump on the surface of the device. Therefore, the problem that the chip resin embedded in the cutting groove having a depth corresponding to the finished thickness of the device is caused by the back grinding process in the same manner as the above invention and the quality of the package device is deteriorated. In addition to eliminating the problem of causing clogging, the backside grinding process is applied to the wafer with the electrode bumps formed on the surface of the device as in the conventional processing method. It is possible to prevent the problem that the marks remain.

The perspective view of the semiconductor wafer as a wafer divided | segmented by the processing method of the wafer by this invention. Explanatory drawing of the protection member sticking process in the processing method of the wafer by this invention. Explanatory drawing of the back surface grinding process in the processing method of the wafer by this invention. Explanatory drawing of the board | substrate sticking process in the processing method of the wafer by this invention. The perspective view of the semiconductor wafer in which the electrode bump formation process was implemented in the processing method of the wafer by the present invention. The principal part perspective view of the cutting device for implementing the division | segmentation process in the processing method of the wafer by this invention. Explanatory drawing of the division | segmentation process in the processing method of the wafer by this invention. Explanatory drawing of the molding process in the processing method of the wafer by this invention. Explanatory drawing which shows the bump exposure process in the processing method of the wafer by this invention. Explanatory drawing of the wafer transfer process in the processing method of the wafer by this invention. Explanatory drawing of the mold resin removal process in the processing method of the wafer by this invention. The principal part perspective view of the cutting device for enforcing 1st Embodiment of the mold resin cutting process in the processing method of the wafer by this invention. Explanatory drawing which shows 1st Embodiment of the mold resin cutting process in the processing method of the wafer by this invention. The principal part perspective view of the laser processing apparatus for enforcing 2nd Embodiment of the mold resin cutting process in the processing method of the wafer by this invention. Explanatory drawing which shows 2nd Embodiment of the mold resin cutting process in the processing method of the wafer by this invention. The perspective view of the semiconductor wafer in which the mold resin cutting process in the processing method of the wafer by this invention was implemented, and the perspective view of each divided | segmented package device. Explanatory drawing of the probing process in the processing method of the wafer by this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer processing method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a perspective view of a semiconductor wafer as a wafer to be processed according to the present invention. The semiconductor wafer 2 shown in FIG. 1 is made of a silicon wafer having a thickness of, for example, 600 μm, and a plurality of division lines 21 are formed in a lattice shape on the surface 2a and are partitioned by the plurality of division lines 21. In addition, devices 22 such as IC and LSI are formed in a plurality of regions. Each device 22 has the same configuration. Electrode bumps 23 that are a plurality of protruding electrodes are formed on the surface of the device 22. The electrode bumps 23 do not necessarily have to be formed at the time of manufacturing the semiconductor wafer 2, and after performing a substrate attaching step described later as in another embodiment of the present invention, before performing a dividing step described later. In addition, electrode bumps may be formed on the surface of the device 22. Hereinafter, a wafer processing method for dividing the semiconductor wafer 2 into the individual devices 22 along the division line 21 and generating a package device in which the outer periphery of each device is covered with a mold resin will be described.

  First, a protective member attaching step for attaching a protective member to the surface of the semiconductor wafer 2 is performed. That is, as shown in FIG. 2, a protective tape 3 as a protective member is attached to the surface 2a of the semiconductor wafer 2. In the illustrated embodiment, the protective tape 3 has an acrylic resin-based paste applied to the surface of a sheet-like substrate made of polyvinyl chloride (PVC) having a thickness of 100 μm to a thickness of about 5 μm.

  If the above-described protective member attaching step is performed, the back surface grinding step is performed in which the back surface of the semiconductor wafer 2 is ground to form the semiconductor wafer 2 to the finished thickness of the device. This back grinding process is performed using a grinding apparatus 4 shown in FIG. A grinding apparatus 4 shown in FIG. 3A includes a chuck table 41 that holds a workpiece, and a grinding means 42 that grinds the workpiece held on the chuck table 41. The chuck table 41 is configured to suck and hold a workpiece on the upper surface, which is a holding surface, and is rotated in a direction indicated by an arrow 41a in FIG. The grinding means 42 includes a spindle housing 421, a rotating spindle 422 that is rotatably supported by the spindle housing 421 and rotated by a rotation driving mechanism (not shown), a mounter 423 attached to the lower end of the rotating spindle 422, and the mounter And a grinding wheel 424 attached to the lower surface of 423. The grinding wheel 424 includes an annular base 425 and a grinding wheel 426 that is annularly attached to the lower surface of the base 425, and the base 425 is attached to the lower surface of the mounter 423 by fastening bolts 427. ing.

  In order to perform the back surface grinding process using the grinding apparatus 4 described above, a semiconductor wafer in which the protective member attaching process is performed on the upper surface (holding surface) of the chuck table 41 as shown in FIG. 2 side of the protective tape 3 is placed. The semiconductor wafer 2 is sucked and held on the chuck table 41 via the protective tape 3 by operating a suction means (not shown). Accordingly, the back surface 2b of the semiconductor wafer 2 held on the chuck table 41 is on the upper side. If the semiconductor wafer 2 is sucked and held on the chuck table 41 via the protective tape 3 in this way, the grinding means is rotated while rotating the chuck table 41 in the direction indicated by the arrow 41a in FIG. 42, the grinding wheel 424 is rotated in the direction indicated by the arrow 424a in FIG. 3A at, for example, 6000 rpm, and the grinding wheel 426 is processed as shown in FIG. 2b, and the grinding wheel 424 is moved downward (perpendicular to the holding surface of the chuck table 41) at a grinding feed rate of 1 μm / second, for example, as indicated by an arrow 424b in FIGS. 3 (a) and 3 (b). Direction). As a result, the back surface 2b of the semiconductor wafer 2 is ground, and as shown in FIG. 3B, the semiconductor wafer 2 is formed with a finished thickness of the device (for example, 200 μm).

  Next, a substrate is attached to attach a rigid substrate to the back surface of the semiconductor wafer 2 on which the back grinding process has been performed, and to peel off the protective tape 3 as a protective member attached to the front surface 2a of the semiconductor wafer 2. Perform the process. That is, as shown in FIGS. 4A and 4B, a glass plate 5 as a rigid substrate is attached to the back surface 2b of the semiconductor wafer 2 by brazing, for example, and is attached to the surface 2a of the semiconductor wafer 2 The protective tape 3 is peeled off.

If the above-mentioned substrate pasting process is carried out, when the semiconductor wafer 2 described above is manufactured and the electrode bumps 23 are not formed on the front surface of the device 22, the glass plate 5 is pasted on the back surface as shown in FIG. Electrode bumps 23 are formed on the surfaces of a plurality of devices 22 formed on the attached semiconductor wafer 2 by a well-known method of forming electrode bumps 23 when the semiconductor wafer 2 shown in FIG. 1 is manufactured (electrode bump formation). Process). Thus, the following operation effects are obtained by performing an electrode bump formation process after implementing a protection member adhesion process, a back surface grinding process, and a substrate adhesion process. That is, as shown in FIG. 1, in the case where the electrode bumps 23 are formed on the surface of the device 22 at the time of manufacturing the semiconductor wafer 2, the protective member sticking step is performed and the surface of the semiconductor wafer 2 is used as a protective member. Even if the back surface grinding step is performed after the protective tape 3 is adhered, there is a problem in that grinding marks corresponding to the electrode bumps 23 remain on the back surface of the semiconductor wafer 2 ground by the protrusions of the electrode bumps 23. However, in this embodiment, since the electrode bump forming step is performed after the protective member attaching step, the back surface grinding step, and the substrate attaching step, the electrode bumps are formed on the surface of the device when the back surface grinding step is performed. Since it does not exist, the problem that grinding traces corresponding to the electrode bumps remain on the back surface of the semiconductor wafer 2 by performing the back surface grinding step can be prevented.
In addition, you may implement an electrode bump formation process, after implementing the division | segmentation process mentioned later.

  Next, a dividing step is performed in which the semiconductor wafer 2 is divided into individual devices by cutting along the planned dividing line 21 by a cutting blade having a first thickness from the surface 2a side of the semiconductor wafer 2 to form divided grooves. To do. This dividing step is performed using the cutting device 6 shown in FIG. 6 in the illustrated embodiment. 6 includes a chuck table 61 that holds a workpiece, a cutting unit 62 that cuts the workpiece held on the chuck table 61, and a workpiece that is held on the chuck table 61. An image pickup means 63 for picking up images is provided. The chuck table 61 is configured to suck and hold a workpiece. The chuck table 61 is moved in a cutting feed direction indicated by an arrow X in FIG. 6 by a cutting feed means (not shown) and is indicated by an arrow Y by an index feed means (not shown). It can be moved in the index feed direction shown.

  The cutting means 62 includes a spindle housing 621 arranged substantially horizontally, a rotating spindle 622 rotatably supported by the spindle housing 621, and an annular cutting blade 623a attached to the tip of the rotating spindle 622. The rotary spindle 622 is rotated in a direction indicated by an arrow 622a by a servo motor (not shown) disposed in the spindle housing 621. The annular cutting edge 623a of the cutting blade 623 is set to a first thickness of 50 μm in the illustrated embodiment. The imaging means 63 is composed of optical means such as a microscope and a CCD camera, and sends the captured image signal to a control means (not shown).

  In order to perform the cutting groove forming process using the cutting device 6 described above, the glass plate 5 side attached to the back surface 2b of the semiconductor wafer 2 is placed on the chuck table 61 as shown in FIG. The semiconductor wafer 2 is sucked and held on the chuck table 61 through the glass plate 5 by operating the suction means that does not. Therefore, the surface 2a of the semiconductor wafer 2 held on the chuck table 61 via the glass plate 5 is on the upper side. In this way, the chuck table 61 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging means 63 by a cutting feed means (not shown).

  When the chuck table 61 is positioned immediately below the image pickup means 63, an alignment operation for detecting a cutting region in which a division groove is to be formed along the division line 21 of the semiconductor wafer 2 is executed by the image pickup means 63 and a control means (not shown). . That is, the imaging unit 63 and a control unit (not shown) execute image processing such as pattern matching for aligning the planned division line 21 formed in a predetermined direction of the semiconductor wafer 2 with the cutting blade 623, Align the cutting area (alignment process). In addition, the alignment of the cutting region is similarly performed on the division line 21 that is formed in the semiconductor wafer 2 and extends in a direction orthogonal to the predetermined direction.

  When the alignment for detecting the cutting area of the semiconductor wafer 2 held on the chuck table 61 is performed as described above, the chuck table 61 holding the semiconductor wafer 2 is moved to the cutting start position of the cutting area. To do. At this time, as shown in FIG. 7A, in the semiconductor wafer 2, one end (the left end in FIG. 7A) of the planned dividing line 21 is on the right side by a predetermined amount from directly below the annular cutting edge 623a of the cutting blade 623. Positioned to be located. Next, the cutting blade 623 is cut and sent downward from the standby position indicated by a two-dot chain line in FIG. 7A as indicated by an arrow Z1, and a predetermined cutting and feeding is indicated as indicated by a solid line in FIG. 7A. Position to position. This cutting feed position is set to a position where the lower end of the annular cutting edge 623a of the cutting blade 623 reaches the glass plate 5 as shown in FIG.

  Next, the cutting blade 623 is rotated at a predetermined rotational speed in the direction indicated by the arrow 622a in FIG. 7A, and the chuck table 61 is rotated at the predetermined cutting feed speed in the direction indicated by the arrow X1 in FIG. Move with. Then, when the other end of the planned dividing line 21 (the right end in FIG. 7B) reaches a position that is a predetermined amount to the left of the cutting blade 623 just below the annular cutting edge 623a, the movement of the chuck table 61 is stopped. To do. By cutting and feeding the chuck table 61 in this way, as shown in FIG. 7D, the semiconductor wafer 2 is formed with the dividing groove 210 along the scheduled dividing line 21 (dividing step).

  Next, the cutting blade 623 is raised as shown by an arrow Z2 in FIG. 7B and positioned at a standby position shown by a two-dot chain line, and the chuck table 61 is moved in the direction shown by an arrow X2 in FIG. 7B. Move to return to the position shown in FIG. Then, the chuck table 61 is indexed and fed in the direction perpendicular to the paper surface (index feed direction) by an amount corresponding to the interval between the scheduled division lines 21, and the next scheduled division line 21 to be cut is placed at a position corresponding to the cutting blade 623. Positioning is performed, and the above-described division process is performed along the division line 21 to be cut next. When the above-described dividing process is performed along all the planned dividing lines 21 formed in the predetermined direction as described above, the chuck table 61 is rotated 90 degrees to form the divided planned lines formed in the predetermined direction. The above-described dividing step is performed along the planned dividing line 21 extending in a direction orthogonal to the 21. As a result, the semiconductor wafer 2 is divided into individual devices 22 by dividing grooves 210 formed along the planned dividing line 21.

  Next, a molding step is performed in which the dividing step is performed and a molding resin is laid on the surface of the semiconductor wafer 2 divided into individual devices, and the molding resin is embedded in the dividing grooves 210. In this molding process, as shown in FIG. 8 (a), the glass adhered to the back surface 2b of the semiconductor wafer 2 on which the above-described dividing process has been performed on the holding surface which is the upper surface of the holding table 71 of the resin coating apparatus 7. The semiconductor wafer 2 is sucked and held on the holding table 71 via the glass plate 5 by placing the plate 5 side and operating a suction means (not shown). Accordingly, the semiconductor wafer 2 held on the holding table 71 via the glass plate 5 has the surface 2a on the upper side. If the semiconductor wafer 2 is held on the holding table 71 in this way, the ejection port 721 of the resin supply nozzle 72 is placed on the holding table 71 as shown in FIG. The resin supply means (not shown) is operated at a central portion, and a predetermined amount of mold resin 70 is dropped from the jet port 721 of the resin supply nozzle 72 onto the central region of the semiconductor wafer 2 held on the holding table 71. If a predetermined amount of mold resin 70 is dropped onto the central region of the surface 2a of the semiconductor wafer 2, the holding table 71 is rotated in the direction indicated by the arrow 71a at a predetermined rotation speed for a predetermined time as shown in FIG. Thus, as shown in FIGS. 8B and 8C, the mold resin 70 is laid on the surface 2a of the semiconductor wafer 2 and the mold resin 70 is embedded in the dividing grooves 210. In the illustrated embodiment, the mold resin 70 is a thermosetting liquid resin (epoxy resin), and is laid on the surface 2 a of the semiconductor wafer 2 and embedded in the dividing groove 210. It can be cured by heating at about 150 ° C.

  In the embodiment described above, since the molding process is performed after the protective member attaching process, the back surface grinding process, the substrate attaching process, and the dividing process are performed, there is no mold resin when the back surface grinding process is performed. Therefore, by performing the back surface grinding process, the mold resin embedded in the cutting groove having a depth corresponding to the finished thickness of the device causes smoldering and deteriorates the quality of a package device called a wafer level chip size package (WLCSP). At the same time, it is possible to prevent the problem that the grinding wheel is crushed.

  Next, the mold resin 70 laid on the surface 2 a of the semiconductor wafer 2 is polished, and a bump exposure process is performed to expose the electrode bumps 23 formed on the surface of the device 22. This bump exposure process is performed using a polishing apparatus 8 shown in FIG. A polishing apparatus 8 shown in FIG. 9A includes a chuck table 81 that holds a workpiece and a polishing means 82 that polishes the workpiece held on the chuck table 81. The chuck table 81 is configured to suck and hold the workpiece on the upper surface, and is rotated in a direction indicated by an arrow 81a in FIG. 9A by a rotation driving mechanism (not shown). The polishing means 82 includes a spindle housing 821, a rotary spindle 822 that is rotatably supported by the spindle housing 821 and rotated by a rotary drive mechanism (not shown), a mounter 823 attached to the lower end of the rotary spindle 822, and the mounter And a polishing tool 824 attached to the lower surface of 823. The polishing tool 824 includes a circular base 825 and a polishing pad 826 attached to the lower surface of the base 825, and the base 825 is attached to the lower surface of the mounter 823 with fastening bolts 827. . In the illustrated embodiment, the polishing pad 826 is mixed with abrasive grains made of silica as an abrasive in the felt.

In order to perform the bump exposing process using the polishing apparatus 8 described above, the back surface of the semiconductor wafer 2 on which the molding process is performed on the upper surface (holding surface) of the chuck table 81 as shown in FIG. The semiconductor wafer 2 is sucked and held on the chuck table 81 through the glass plate 5 by placing the glass plate 5 attached to 2b and operating a suction means (not shown) (wafer holding step). Accordingly, in the semiconductor wafer 2 held on the chuck table 81 via the glass plate 5, the mold resin 70 laid on the surface 2a is on the upper side. If the semiconductor wafer 2 is sucked and held on the chuck table 81 in this way, the polishing tool of the polishing means 82 is rotated while the chuck table 81 is rotated at a predetermined rotational speed in the direction indicated by the arrow 81a in FIG. 824 is rotated at a predetermined rotational speed in a direction indicated by an arrow 824a in FIG. 9A, and a polishing pad 826 is laid on the surface 2a which is a work surface as shown in FIG. 8B. The upper surface of the resin 70 is brought into contact, and the polishing tool 824 is moved downward (perpendicular to the holding surface of the chuck table 81) at a predetermined polishing feed rate as indicated by an arrow 824b in FIGS. 9 (a) and 9 (b). Direction). As a result, as shown in FIG. 9C, the mold resin 70 laid on the surface 2a is polished, and the electrode bumps 23 formed on the surface of the device 22 are exposed.
When the molding resin 70 is laid on the surface 2a of the semiconductor wafer 2 without covering the electrode bumps 23 in the molding process, the bump exposing process described above is not necessarily required.

  Next, the glass plate 5 attached by brazing to the back surface of the semiconductor wafer 2 on which the molding process and the bump exposing process are performed is peeled off, and the back surface of the semiconductor wafer 2 is mounted on an annular frame. The wafer transfer process to be attached to the wafer is carried out. That is, as shown in FIG. 10A, the glass plate 5 attached by brazing to the back surface of the semiconductor wafer 2 on which the molding process and the bump exposure process have been performed is peeled off, and FIG. The back surface 2b of the semiconductor wafer 2 from which the glass plate 5 has been peeled off is attached to the surface of the dicing tape T mounted on the annular frame F as shown in FIG. Accordingly, in the semiconductor wafer 2 adhered to the surface of the dicing tape T, the mold resin 70 laid on the surface is on the upper side.

  When the wafer transfer process described above is performed, the outer periphery of the mold resin 70 laid on the surface of the semiconductor wafer 2 is removed in an annular shape to expose the divided grooves 210, and the mold resin 70 embedded in the divided grooves 210. A mold resin removing step for exposing the semiconductor wafer 2 to the surface of the semiconductor wafer 2 is performed. In the illustrated embodiment, this mold resin removing step is performed using a cutting device 60 shown in FIG. The cutting device 60 shown in FIG. 11A has the same configuration except for the cutting device 6 and the annular cutting edge 623a of the cutting blade 623 shown in FIG. The description is omitted. The annular cutting edge 623b of the cutting blade 623 in the cutting device 60 shown in FIG. 11A has a thickness set to 2 to 3 mm.

  In order to perform the mold resin removing step using the cutting device 60 shown in FIG. 11A, the dicing tape T side of the semiconductor wafer 2 on which the wafer transfer step is performed on the chuck table 61 of the cutting device 60 is performed. Is placed. Then, the semiconductor wafer 2 is sucked and held on the chuck table 61 via the dicing tape T by operating a suction means (not shown). Accordingly, in the semiconductor wafer 2 held on the chuck table 61 via the dicing tape T, the mold resin 70 laid on the surface of the semiconductor wafer 2 is on the upper side. In FIG. 11A, the annular frame F on which the dicing tape T is mounted is omitted, but the annular frame F is held by an appropriate frame holding means disposed on the chuck table 61. The In this way, the chuck table 61 that sucks and holds the semiconductor wafer 2 is moved to a cutting region by the cutting blade 623, and the outer periphery of the semiconductor wafer 2 is directly below the cutting blade 623 as shown in FIG. Position.

  Next, the cutting blade 623 is rotated at a predetermined rotational speed in the direction indicated by the arrow 622a in FIG. 11A, and cut and fed downward as indicated by the arrow Z1. This cutting feed position is set to a position that reaches the surface of the semiconductor wafer 2 on which the mold resin 70 is laid. Then, the chuck table 61 is rotated once in the direction indicated by the arrow 61a in FIG. As a result, as shown in FIG. 11B, the outer peripheral portion of the mold resin 70 laid on the surface of the semiconductor wafer 2 is removed in an annular shape so that the divided grooves 210 are exposed and the mold embedded in the divided grooves 210. The resin 70 is exposed on the surface of the semiconductor wafer 2.

  Next, the central portion in the width direction of the mold resin 70 embedded in the division groove 210 formed in the semiconductor wafer 2 on which the molding process has been performed is cut along the division groove 210 so that the outer periphery of the device 22 is made of mold resin. A mold resin cutting process for generating a covered package device is performed. A first embodiment of this mold resin cutting step will be described with reference to FIGS.

  The first embodiment of the mold resin cutting step is performed using a cutting apparatus 600 shown in FIG. The cutting device 600 shown in FIG. 12 has the same configuration except for the cutting device 6 shown in FIG. 6 and the annular cutting edge 623a of the cutting blade 623. Omitted. The annular cutting edge 623c of the cutting blade 623 in the cutting apparatus 600 shown in FIG. 12 is set to 20 μm, which is a second thickness that is thinner than the first thickness (50 μm) of the annular cutting edge 623a.

  In order to perform the cutting process using the cutting apparatus 600 shown in FIG. 12, the dicing tape T side of the semiconductor wafer 2 on which the mold resin removing process has been performed is placed on the chuck table 61. Then, the semiconductor wafer 2 is sucked and held on the chuck table 61 via the dicing tape T by operating a suction means (not shown). Therefore, the semiconductor wafer 2 held on the chuck table 61 has the mold resin 70 laid on the surface on the upper side. In FIG. 12, the annular frame F to which the dicing tape T is mounted is omitted, but the annular frame F is held by an appropriate frame holding means provided on the chuck table 61. In this way, the chuck table 61 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging means 63 by a cutting feed means (not shown).

  When the chuck table 61 is positioned directly below the image pickup means 63, the alignment for detecting the cutting region to be cut of the mold resin 70 embedded in the dividing groove 210 formed in the semiconductor wafer 2 by the image pickup means 63 and a control means (not shown). Perform work. That is, the image pickup means 63 and a control means (not shown) are used for aligning the mold blade 70 embedded in the divided groove 210 exposed on the outer periphery of the semiconductor wafer 2 and formed in a predetermined direction with the cutting blade 623. Image processing is executed to perform alignment of the cutting area (alignment process). Further, the alignment of the cutting region is similarly performed on the mold resin 70 embedded in the dividing groove 210 formed in the direction orthogonal to the predetermined direction formed in the semiconductor wafer 2. In this alignment process, since the mold resin 70 embedded in the dividing groove 210 is exposed on the outer peripheral surface of the semiconductor wafer 2, the imaging resin 63 images the mold resin 70 embedded in the dividing groove 210. It can be detected clearly.

  When the alignment for detecting the cutting area of the semiconductor wafer 2 held on the chuck table 61 is performed as described above, the chuck table 61 holding the semiconductor wafer 2 is moved to the cutting start position of the cutting area. To do. At this time, as shown in FIG. 13A, the semiconductor wafer 2 has one end of the mold resin 70 embedded in the dividing groove 210 to be cut (the left end in FIG. 13A) as an annular cut of the cutting blade 623. The center of the mold resin 70 embedded in the dividing groove 210 is positioned at a position corresponding to the cutting blade 623 while being positioned so as to be located a predetermined amount to the right of directly below the blade 623c.

  When the semiconductor wafer 2 held on the chuck table 61 of the cutting apparatus 600 is positioned at the cutting start position in the cutting region in this way, the cutting blade 623 is indicated by a two-dot chain line in FIG. It cuts and feeds downward from the standby position as indicated by an arrow Z1, and is positioned at a predetermined cutting and feeding position as shown by a solid line in FIG. This cutting feed position is set to a position where the lower end of the annular cutting edge 623c of the cutting blade 623 reaches the dicing tape T adhered to the back surface of the semiconductor wafer 2 as shown in FIG.

  Next, the cutting blade 623 is rotated at a predetermined rotational speed in the direction indicated by an arrow 622a in FIG. 13A, and the chuck table 61 is rotated at a predetermined cutting feed speed in the direction indicated by an arrow X1 in FIG. Move with. When the other end (the right end in FIG. 13B) of the mold resin 70 embedded in the dividing groove 210 reaches a position located to the left by a predetermined amount from directly below the annular cutting edge 623c of the cutting blade 623, the chuck The movement of the table 61 is stopped. By cutting and feeding the chuck table 61 in this way, the mold resin 70 laid on the surface of the semiconductor wafer 2 and the mold resin 70 embedded in the dividing groove 210 are dicing tape T as shown in FIG. Is completely cut by a cutting groove 710 having a width of 20 μm (mold resin cutting step). In this mold resin cutting step, the center in the width direction of the mold resin 70 embedded in the division groove 210 detected in the alignment step and exposed on the outer peripheral surface of the semiconductor wafer 2 is positioned at a position corresponding to the cutting blade 623. Therefore, even if the mold resin 70 is laid on the surface of the semiconductor wafer 2, the center in the width direction of the mold resin 70 embedded in the division groove 210 can be accurately cut along the division groove 210 by the cutting blade 623. Yes, without damaging the sides of the device.

  Next, the cutting blade 623 is raised as shown by an arrow Z2 in FIG. 13B and positioned at a standby position shown by a two-dot chain line, and the chuck table 61 is moved in the direction shown by an arrow X2 in FIG. Move to return to the position shown in FIG. Then, the chuck table 61 is indexed and fed in the direction perpendicular to the paper surface (index feed direction) by an amount corresponding to the interval between the divided grooves 210 in which the mold resin 70 is embedded (interval of the scheduled division line 21), and then cut. The mold resin 70 embedded in the power dividing groove 210 is positioned at a position corresponding to the cutting blade 623, and the above-described mold resin cutting step is performed along the mold resin 70 embedded in the power dividing groove 210 to be cut. When the above-described mold resin cutting step is performed along the mold resin 70 embedded in all the dividing grooves 210 formed in the predetermined direction in this way, the chuck table 61 is rotated 90 degrees to The above-described mold resin cutting step is performed along the mold resin 70 embedded in the divided groove 210 formed in the direction orthogonal to the mold resin 70 embedded in the divided groove 210 formed in the direction.

  Next, a second embodiment of the mold resin cutting step will be described with reference to FIGS. 14 and 15. The second embodiment of the mold resin cutting step is performed using a laser processing apparatus 9 shown in FIG. A laser processing apparatus 9 shown in FIG. 14 has a chuck table 91 that holds a workpiece, laser beam irradiation means 92 that irradiates the workpiece held on the chuck table 91 with a laser beam, and a chuck table 91 that holds the workpiece. An image pickup means 93 for picking up an image of the processed workpiece is provided. The chuck table 91 is configured to suck and hold a workpiece, and can be moved in a machining feed direction indicated by an arrow X and an index feed direction indicated by an arrow Y in FIG. Yes.

  The laser beam irradiation means 92 irradiates a pulse laser beam from a condenser 922 attached to the tip of a cylindrical casing 921 arranged substantially horizontally. In the illustrated embodiment, the focused spot of the pulse laser beam emitted from the condenser 922 has a diameter smaller than the first thickness (50 μm) of the annular cutting edge 623a of the cutting blade 623 in the cutting device 6 described above. It is set to a certain 10 μm. The image pickup means 93 attached to the tip of the casing 921 constituting the laser beam irradiation means 92 includes an illumination means for illuminating a workpiece, an optical system for capturing an area illuminated by the illumination means, and the optical An image pickup device (CCD) for picking up an image captured by the system is provided, and the picked-up image signal is sent to a control means (not shown).

A second embodiment of the dividing process performed using the laser processing apparatus 9 described above will be described with reference to FIGS. 14 and 15.
In the molding resin cutting step, first, the dicing tape T side of the semiconductor wafer 2 on which the molding resin removing step has been performed is placed on the chuck table 91 of the laser processing apparatus 9 shown in FIG. Then, the semiconductor wafer 2 is sucked and held on the chuck table 91 via the dicing tape T by operating a suction means (not shown). Accordingly, the semiconductor wafer 2 held on the chuck table 91 has the mold resin 70 laid on the surface on the upper side. In FIG. 14, the annular frame F to which the dicing tape T is attached is omitted, but the annular frame F is held by an appropriate frame holding means provided on the chuck table 91. In this manner, the chuck table 91 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging unit 93 by a cutting feed unit (not shown).

  When the chuck table 91 is positioned immediately below the image pickup means 93, the alignment for detecting the cutting region to be cut of the mold resin 70 embedded in the dividing groove 210 formed in the semiconductor wafer 2 by the image pickup means 93 and a control means (not shown). Perform work. That is, the image pickup means 93 and the control means (not shown) include a mold resin 70 embedded in the dividing groove 210 exposed on the outer periphery of the semiconductor wafer 2 and formed in a predetermined direction, and a mold resin 70 embedded in the dividing groove 210. Alignment is performed for alignment with the condenser 922 of the laser beam application means 92 that irradiates the laser beam along (alignment step). Further, the alignment of the cutting region is similarly performed on the mold resin 70 embedded in the dividing groove 210 formed in the direction orthogonal to the predetermined direction formed in the semiconductor wafer 2. In this alignment step, since the mold resin 70 embedded in the dividing groove 210 is exposed on the outer peripheral surface of the semiconductor wafer 2, the mold resin 70 embedded in the dividing groove 210 is imaged by the imaging means 93. It can be detected clearly.

  As described above, the mold resin 70 embedded in the dividing groove 210 formed along the planned dividing line 21 formed in the semiconductor wafer 2 held on the chuck table 91 is detected, and the position of the laser beam irradiation position is detected. When the alignment is performed, the chuck table 91 is moved to the laser beam irradiation region where the condenser 922 of the laser beam irradiation means 92 for irradiating the laser beam is positioned as shown in FIG. One end (the left end in FIG. 15A) of the mold resin 70 embedded in the laser beam is positioned directly below the condenser 922 of the laser beam irradiation means 92 and embedded in the dividing groove 210 as shown in FIG. The center of the molded resin 70 in the width direction is positioned directly below the light collector 922. Then, the condensing point P of the pulsed laser beam irradiated from the condenser 922 is embedded in the dividing groove 210 and exposed on the back surface 2b of the semiconductor wafer 2 as shown in FIG. Position. In addition, the condensing spot diameter of the pulse laser beam irradiated from the condenser 922 is set to φ10 μm in the illustrated embodiment. Therefore, the condenser 922 irradiates a pulse laser beam thinner than the first thickness (50 μm) of the annular cutting edge 623a of the cutting blade 623. Next, the chuck table 91 is moved at a predetermined feed speed in the direction indicated by the arrow X1 in FIG. 15A while irradiating the mold resin 70 with a pulsed laser beam having an absorption wavelength from the condenser 922. . 15B, when the irradiation position of the condenser 922 of the laser beam irradiation means 92 reaches the position of the other end of the dividing groove 210, the irradiation of the pulse laser beam is stopped and the chuck table 91 is moved. Stop. As a result, as shown in FIG. 15D, the mold resin 70 laid on the surface of the semiconductor wafer 2 and the mold resin 70 embedded in the dividing groove 210 have a width that reaches the dicing tape T along the dividing groove 210. Is formed with a laser processed groove 720 of approximately 10 μm. In the second embodiment of this mold resin cutting step, the center of the mold resin 70 in the width direction embedded in the dividing groove 210 that is detected in the alignment step and exposed on the outer peripheral surface of the semiconductor wafer 2 is a concentrator. Since it is positioned directly below 922, even if the mold resin 70 is laid on the surface of the semiconductor wafer 2, a pulse laser beam is irradiated along the split groove 210 at the center in the width direction of the mold resin 70 embedded in the split groove 210. Can and will not damage the device.

In addition, the processing conditions in the said mold resin removal process are set as follows, for example.
Wavelength: 355 nm pulse laser Repeat frequency: 100 kHz
Average output: 2W
Condensing spot diameter: φ10μm
Processing feed rate: 100 mm / sec

  When the mold resin cutting step is performed along the dividing groove 210 formed along the predetermined dividing line 21 as described above, the chuck table 91 is moved in the direction perpendicular to the paper surface (index feeding direction) in FIG. ) Is indexed and fed by an amount corresponding to the interval between the divided grooves 210 in which the mold resin 70 is embedded (the interval between the division planned lines 21), and the mold resin cutting step is performed. When the mold resin cutting step is performed along the mold resin 70 embedded in all the dividing grooves 210 formed in the predetermined direction in this manner, the chuck table 91 is rotated 90 degrees to The mold resin cutting step is performed along the mold resin 70 embedded in the split groove 210 formed in a direction orthogonal to the mold resin 70 embedded in the split groove 210 formed in the above.

  As a result of performing the first embodiment or the second embodiment in the mold resin cutting step described above, the semiconductor wafer 2 cuts the mold resin 70 embedded in the dividing groove 210 as shown in FIG. The device 22 is divided into individual devices by the cutting groove 710 or the laser processing groove 720, and the individually divided device 22 is a wafer level chip size package whose surface and side surfaces are coated with a mold resin 70 as shown in FIG. It constitutes a package device called (WLCSP).

  Next, a probing process for conducting an electrical test of the device 22 formed on the semiconductor wafer 2 will be described. This probing step is performed after the molding step and before the mold resin cutting step. That is, as shown in FIG. 17, the electrical test of the device 22 is performed by applying the probe needle 101 connected to the inspection circuit 10 to the electrode bump 23 formed on the surface 2a of the device 22 formed on the surface 2a of the semiconductor wafer 2. . By performing the probing process in this way, it is possible to confirm the quality of each device 22 before performing the mold resin cutting process for generating a package device in which the outer periphery of the device 22 is covered with the mold resin. .

2: Semiconductor wafer 21: Planned division line 22: Device 3: Protection tape 4: Grinding device 41: Chuck table 42 of grinding device: Grinding means 422: Grinding wheel 5: Glass plate 6, 60, 600: Cutting device 61: Cutting Chuck table 62 of apparatus: cutting means 623: cutting blade 7: resin coating apparatus 70: mold resin 8: polishing apparatus 81: chuck table 82 of polishing apparatus: polishing means 824: polishing tool 9: laser processing apparatus 91: laser processing apparatus Chuck table 92: laser beam irradiation means 922: collector 101: probe needle F: annular frame T: dicing tape

Claims (6)

A wafer processing method in which a plurality of division lines are formed in a lattice shape on the surface and a device having bumps on the surface is formed in a plurality of regions partitioned by the plurality of division lines,
A protective member attaching step for attaching a protective member to the surface of the wafer;
Grinding the back surface of the wafer on which the protective member attaching step has been carried out to form the wafer in the finished thickness of the device; and
A substrate pasting step of pasting a rigid substrate on the back surface of the wafer subjected to the back grinding step and peeling off the protective member stuck on the surface of the wafer;
A division step of dividing the wafer into individual devices by cutting along the division line by a cutting blade having a first thickness from the surface side of the wafer on which the substrate pasting step has been performed to form division grooves;
A molding process in which the dividing step is performed and a molding resin is laid on the surface of the wafer divided into individual devices and the molding resin is embedded in the dividing grooves;
A package device in which the outer periphery of the device is covered with the mold resin is produced by cutting the central portion in the width direction of the mold resin embedded in the division groove formed on the wafer subjected to the molding process along the division groove. Including a mold resin cutting step.
A method for processing a wafer. A wafer processing method in which a plurality of division lines are formed in a lattice shape on a surface and a device is formed in a plurality of regions partitioned by the plurality of division lines.
A protective member attaching step for attaching a protective member to the surface of the wafer;
Grinding the back surface of the wafer on which the protective member attaching step has been carried out to form the wafer in the finished thickness of the device; and
A substrate pasting step of pasting a rigid substrate on the back surface of the wafer subjected to the back grinding step and peeling off the protective member stuck on the surface of the wafer;
An electrode bump forming step of forming electrode bumps on the surface of the wafer on which the substrate pasting step has been performed;
A dividing step of dividing the wafer into individual devices by forming a dividing groove by cutting along a dividing line by a cutting blade having a first thickness from the surface side of the wafer;
A molding step of laying a mold resin on the surface of the wafer divided into individual devices by performing the division step and the electrode bump forming step, and embedding the mold resin in the division groove;
A package device in which the outer periphery of the device is covered with the mold resin is produced by cutting the central portion in the width direction of the mold resin embedded in the division groove formed on the wafer subjected to the molding process along the division groove. Including a mold resin cutting step.
A method for processing a wafer.   The mold resin cutting step includes cutting a central portion in the width direction of the mold resin embedded in the dividing groove formed on the wafer by a cutting blade having a second thickness smaller than the first thickness along the dividing groove. The method for processing a wafer according to claim 1 or 2.   The mold resin cutting step includes irradiating a laser beam thinner than the first thickness along the divided groove to a central portion in the width direction of the mold resin embedded in the divided groove formed on the wafer. The wafer processing method according to claim 1 or 2, wherein a central portion in the direction is cut.   After the molding process is performed, the outer periphery of the mold resin laid on the surface of the wafer is annularly removed to expose the dividing groove, and the mold resin embedded in the dividing groove is exposed on the surface of the wafer. A resin removing step is performed, and the mold resin cutting step is performed, the mold resin removing step is performed, the mold resin embedded in the dividing groove exposed on the outer peripheral portion of the wafer is detected, and the mold embedded in the dividing groove is detected. The wafer processing method according to claim 1, wherein a central portion in the width direction of the resin is cut.   2. A probing step of performing an electrical test of the device by applying a probe needle to an electrode bump formed on the surface of the device after performing the molding step and before performing the molding resin cutting step is performed. Or the processing method of the wafer of 2.