JP2010251416A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device constituted by bonding a second semiconductor device to a reverse surface of a first semiconductor device without lowering quality. <P>SOLUTION: The method of manufacturing the semiconductor device includes a reverse-surface grinding process of grinding a reverse surface of a wafer 2 having a plurality of first devices formed by a laminate having an insulating film and a functional film laminated on a top surface of a substrate, a device bonding process of bonding the second semiconductor device 220 to the reverse surface of the wafer 2 to form a laminated wafer 222, a laminate removing process of irradiating the wafer 2 with a laser light beam along a street 23 defining a plurality of devices, a wafer supporting process of sticking the top surface 2a of the wafer 2 on a dicing tape T mounted on a frame, and a wafer dividing process of processing the wafer 2 from the reverse surface side of the substrate along the streets 23 to separate individual semiconductor devices each having a second semiconductor device 220 bonded to a reverse surface of a first semiconductor device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device in which a second semiconductor device is bonded to the back surface of a first semiconductor device.

  In the semiconductor device manufacturing process, a plurality of regions are defined by dividing lines called streets arranged in a lattice pattern on the surface of a substantially disk-shaped wafer, and devices such as ICs, LSIs, etc. are defined in these partitioned regions. Form. The wafer formed in this way is divided into individual devices along the street, and is widely used in electrical equipment. As a method of dividing the wafer along the street, a method of cutting along the street with a cutting blade using a cutting device is generally used. As a method of dividing the wafer along the street, a method of forming a laser processing groove by irradiating a pulse laser beam along the street of the wafer has been put into practical use.

  On the other hand, in recent years, a semiconductor device has been proposed in which a second semiconductor device is bonded to the back surface of a first semiconductor device in order to reduce the size of an electric device. This semiconductor device is configured by bonding a stud electrode provided on the first semiconductor device and exposed on the back surface and a bonding pad formed on the surface of the second semiconductor device using a flip chip bonding technique.

  Since the semiconductor device formed by bonding the second semiconductor device to the back surface of the first semiconductor device described above is manufactured by assembling the semiconductor devices one by one, each step of transporting and arranging the semiconductor device each time, The step of detecting the position of the semiconductor device must be carried out, which is problematic in terms of productivity.

  In order to solve the above problem, the second semiconductor device is bonded to the back surface of each first semiconductor device in the wafer state before dividing the wafer on which a plurality of first semiconductor devices are formed into individual semiconductor devices. Then, a method of manufacturing a semiconductor device in which the second semiconductor device is bonded to the back surface of the first semiconductor device by dividing the wafer in which a plurality of first semiconductor devices are formed into individual semiconductor devices is described below. It is disclosed in Patent Document 1.

JP 2007-250559 A

Thus, when a wafer having the second semiconductor device bonded to the back surface is cut by a cutting blade from the front surface side along the street formed on the front surface, a gap is formed in a region corresponding to the street on the back surface of the wafer. Since the second semiconductor device is bonded, there is a problem that fine vibration is generated in the vicinity of the gap and chipping occurs along the cutting groove.
Further, when the wafer is divided along the street by irradiating the laser beam from the surface side along the street formed on the surface of the wafer having the second semiconductor device bonded to the back surface, debris generated by the irradiation of the laser beam is generated on the wafer. There exists a problem that it adheres to the side surface of the 2nd semiconductor device joined to the back surface, and reduces the quality of the 2nd semiconductor device.
Further, when the wafer having the second semiconductor device bonded to the back surface is cut from the back surface side along the street formed on the front surface by a cutting blade, a plurality of laminated bodies in which an insulating film and a functional film are stacked on the surface of the substrate are used. However, there is a problem in that the laminated body is peeled off to deteriorate the quality of the first semiconductor device. In other words, in order to improve the processing capability of devices such as IC and LSI, a low dielectric constant insulator film (Low-k film) and circuit made of a glassy material such as SiO2, SiO, SiN on the surface of a substrate such as silicon Wafers in a form in which a device is formed by a laminated body in which functional films forming the layers are laminated have been put into practical use. However, since the Low-k film is different from the material of the wafer, it is difficult to simultaneously cut with the cutting blade. That is, the low-k film is very fragile like mica, so when the cutting blade cuts along the street, the low-k film peels off, and this peeling reaches the circuit, causing fatal damage to the device. There is a problem.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is that the quality of the first semiconductor device and the second semiconductor device bonded to the back surface of the first semiconductor device is not deteriorated. Another object of the present invention is to provide a method of manufacturing a semiconductor device in which a second semiconductor device is bonded to the back surface of the first semiconductor device.

In order to solve the above main technical problem, according to the present invention, there is provided a method for manufacturing a semiconductor device comprising a second semiconductor device bonded to the back surface of a first semiconductor device,
A back surface grinding step of grinding the back surface of the wafer substrate on which the plurality of first devices are formed by a laminate in which an insulating film and a functional film are laminated on the surface of the substrate to form a predetermined thickness;
A device bonding step of bonding the second semiconductor device to a predetermined position corresponding to the first semiconductor device on the back surface of the substrate of the wafer on which the first device is formed, to form a laminated wafer;
A laminate removing step of irradiating a laser beam along a street partitioning a plurality of devices of the wafer on which the first device is formed, and removing the laminate along the street;
A wafer supporting step of attaching the surface of the laminated wafer on which the laminated body removing step has been performed to a dicing tape attached to an annular frame;
Individual semiconductor devices processed along the street from the back side of the wafer substrate constituting the laminated wafer on which the wafer support step has been performed, and the second semiconductor device bonded to the back side of the first semiconductor device And a wafer dividing step to be separated into
A method for manufacturing a semiconductor device is provided.

The laminate removal step may be performed after the device bonding step is performed, may be performed after the back surface grinding step is performed, or may be performed before the back surface grinding step is performed. Good.
In the wafer dividing step, the wafer is cut along the streets with a cutting blade from the back side of the substrate of the wafer constituting the laminated wafer.
In the wafer dividing step, a laser beam is irradiated along the street from the back side of the substrate of the wafer constituting the laminated wafer, and the wafer constituting the laminated wafer is divided along the street.

  According to the present invention, the second semiconductor device is bonded to the back surface of the first semiconductor device by processing along the street from the back surface side of the wafer substrate constituting the laminated wafer on which the wafer support step has been performed. Since the wafer dividing process for separating into individual semiconductor devices is performed, the surface on the lower side of the wafer constituting the laminated wafer is adhered to the dicing tape so that there is no gap, and when the wafer dividing process is performed by a cutting device, Since no vibration is generated by cutting with the cutting blade, no chipping occurs along the cutting groove. When performing the wafer dividing step, the laminated body is removed along the street of the wafer on which the above-mentioned laminated body removing step has already been performed and the first device is formed. Even if it cuts along, a laminated body does not peel. In addition, when the wafer dividing step is performed by a laser processing apparatus, debris generated by laser beam irradiation adheres to the dicing tape and is attached to the side surface of the second semiconductor device joined to the back surface of the wafer constituting the laminated wafer. Debris never adheres.

1 is a perspective view of a wafer on which a plurality of first semiconductor devices used in a method for manufacturing a semiconductor device according to the present invention are formed. FIG. 5 is a perspective view of a wafer on which a plurality of second semiconductor devices used in the method for manufacturing a semiconductor device according to the present invention are formed and the second semiconductor device. Explanatory drawing of the protection member sticking process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing of the back surface grinding process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing of the device joining process in the manufacturing method of the semiconductor device by this invention. FIG. 6 is a perspective view of a wafer on which the device bonding step shown in FIG. 5 is performed. The principal part perspective view of the laser processing apparatus for implementing the laminated body removal process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing of the laminated body removal process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing of the wafer support process in the manufacturing method of the semiconductor device by this invention. The principal part perspective view of the cutting device for enforcing 1st Embodiment of the wafer division | segmentation process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing which shows 1st Embodiment of the wafer division | segmentation process in the manufacturing method of the semiconductor device by this invention. Sectional drawing which expands and shows the wafer where the cutting feed position of the cutting blade in the wafer division | segmentation process shown in FIG. 11 and the wafer division | segmentation process were implemented. The perspective view of the semiconductor device manufactured by the manufacturing method of the semiconductor device by this invention. The principal part perspective view of the laser processing apparatus for enforcing 2nd Embodiment of the wafer division | segmentation process in the manufacturing method of the semiconductor device by this invention. Explanatory drawing which shows 2nd Embodiment of the wafer division | segmentation process in the manufacturing method of the semiconductor device by this invention.

  Preferred embodiments of a method for manufacturing a semiconductor device according to the present invention will be described below in detail with reference to the accompanying drawings.

1A and 1B show a perspective view and an enlarged cross-sectional view of a main part of a wafer on which a plurality of first semiconductor devices used in the method for manufacturing a semiconductor device according to the present invention are formed. A wafer 2 shown in FIGS. 1 (a) and 1 (b) has a plurality of ICs including a laminated body 21 in which a functional film that forms an insulating film and a circuit is laminated on the surface of a substrate 20 such as silicon having a thickness of 700 μm. A first semiconductor device 22 such as an LSI is formed in a matrix. Each first semiconductor device 22 is partitioned by streets 23 formed in a lattice shape. The laminated body 21 is formed to have a thickness of 2 to 10 μm, and the insulating film forming the laminated body 21 is made of SiO 2.
It consists of a low dielectric constant insulator film (Low-k film) made of a glassy material such as SiO or SiN. The wafer 2 includes a plurality of bonding pads 24 disposed on the surface of the device 22 as shown in FIG. 1B, and is connected to the bonding pads 24 and embedded in the silicon substrate 20. A stud electrode 25 made of a metal material such as copper is provided.

  FIGS. 2A and 2B are a perspective view and an enlarged cross-sectional view of a main part of a wafer on which a plurality of second semiconductor devices used in the method for manufacturing a semiconductor device according to the present invention are formed. A wafer 200 shown in FIGS. 2A and 2B is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of second semiconductor devices 220 such as ICs and LSIs are formed in a matrix on the surface 200a. . Each first semiconductor device 220 is partitioned by streets 230 formed in a lattice shape. A bonding pad 240 is formed on the surface of the second semiconductor device 220 at a position corresponding to the stud electrode 25 provided on the first semiconductor device 22. The wafer 200 thus configured is ground along the street 230 by a dicing device such as a cutting device after the back surface 200b is ground and formed to a predetermined thickness, as shown in FIG. 2 (c). Divided into individual second semiconductor devices 220.

Hereinafter, a semiconductor device constituted by bonding the second semiconductor device 220 to the back surface of the first semiconductor device 22 using the wafer 2 and the second semiconductor device 220 in which a plurality of the first semiconductor devices 22 are formed will be described. A manufacturing method will be described.
In the embodiment of the method for manufacturing a semiconductor device according to the present invention, a protective member 3 for protecting the first semiconductor device 22 is attached to the surface 2a of the wafer 2 as shown in FIGS. Wear (protective member sticking step).

  If the protection member sticking process mentioned above is implemented, the back grinding process which grinds the back surface 20b of the board | substrate 20 of the wafer 2 and will form in predetermined thickness will be implemented. This back grinding process is performed by a grinding apparatus shown in FIG. The grinding apparatus 4 shown in FIG. 4 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 sucks and holds the workpiece on the upper surface and is rotated in the direction indicated by the 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 a disk-shaped base 425 and a grinding wheel 426 that is annularly mounted on the lower surface of the base 425, and the base 425 is attached to the lower surface of the mounter 423 with fastening bolts 427. It has been.

  In order to perform the back surface grinding process using the grinding device 4 described above, the protective member 3 side of the wafer 2 on which the protective member attaching process described above has been performed is placed on the upper surface (holding surface) of the chuck table 41. Then, by operating a suction means (not shown), the wafer 2 is sucked and held on the chuck table 41 via the protective member 3. Therefore, the back surface 20b of the substrate 20 is on the upper side of the wafer 2 sucked and held on the chuck table 41 via the protective member 3. If the wafer 2 is sucked and held on the chuck table 41 in this manner, the grinding wheel 424 of the grinding means 42 is rotated in the direction indicated by the arrow 424a, for example, 6000 rpm while the chuck table 41 is rotated in the direction indicated by the arrow 41a, for example, at 300 rpm. , The wafer 2 is brought into contact with the back surface 20b of the substrate 20 of the wafer 2, and the grinding wheel 424 is ground and fed downward by a predetermined amount at a predetermined grinding feed speed to grind the back surface 20b of the substrate 20 of the wafer 2 to thereby remove the wafer 2. It is formed to have a predetermined thickness (for example, 100 μm).

  If the above-described back grinding step is performed, the second semiconductor device 220 is bonded to a predetermined position corresponding to the first semiconductor device 22 on the back surface 20b of the substrate 20 of the wafer 2 on which the back grinding step has been performed, and the laminated wafer. A device bonding step is performed to form a device. This device bonding step will be described with reference to FIGS. That is, as shown in FIGS. 5A and 5B, on the holding table 51 of the bonding apparatus 5, the protective member 3 side adhered to the surface 2a of the wafer 2 on which the back grinding process has been performed as described above. Is placed. Then, by operating a suction means (not shown), the wafer 2 is sucked and held on the holding table 51 via the protective member 3. Therefore, the wafer 2 held on the holding table 51 via the protective member 3 has the back surface 20b of the substrate 20 on the upper side. When the wafer 2 is held on the holding table 51 via the protective member 3 in this way, the second semiconductor device 220 shown in FIG. The wafer 2 held above is transported above a predetermined position corresponding to the first semiconductor device 22 on the back surface 20b of the substrate 20 of the wafer 2. Then, the second semiconductor device 220 is aligned with a predetermined position corresponding to the first semiconductor device 22 on the back surface 20b of the substrate 20 of the wafer 2, and the suction hand 52 is moved as shown in FIG. The second semiconductor device 220 is lowered and bonded to a predetermined position on the back surface 20 b of the substrate 20 of the first semiconductor device 22. Then, by performing this device bonding step at a predetermined position corresponding to all the first semiconductor devices 22 on the back surface 20b of the substrate 20 of the wafer 2, a laminated wafer 222 is formed as shown in FIG. In the above-described device bonding step, the flip-chip bonding technique is used to form the stud electrode 25 (see FIG. 1B) provided on the first semiconductor device 22 and the surface of the second semiconductor device 220. The formed bonding pads 24 ((b) and (c) in FIG. 2) are faced and bonded.

  Next, a laminated body removing step of irradiating a laser beam along the street 23 of the wafer 2 on which the first device 22 is formed and removing the laminated body 21 along the street 23 is performed. This laminated body removal process is implemented using the laser processing apparatus 6 shown in FIG. A laser processing apparatus 6 shown in FIG. 7 has a chuck table 61 that holds a workpiece, a laser beam irradiation means 62 that irradiates a workpiece held on the chuck table 61 with a laser beam, and a chuck table 61 that holds the workpiece. An image pickup means 63 for picking up an image of the processed workpiece is provided. The chuck table 61 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 62 includes a cylindrical casing 621 disposed substantially horizontally. In the casing 621, a pulse laser beam oscillation means including a pulse laser beam oscillator and a repetition frequency setting means (not shown) including a YAG laser oscillator or a YVO4 laser oscillator are arranged. A condenser 622 for condensing the pulse laser beam oscillated from the pulse laser beam oscillating means is attached to the tip of the casing 621. The imaging means 63 attached to the tip of the casing 621 constituting the laser beam irradiation means 62 includes an illumination means for illuminating the workpiece, an optical system for capturing an area illuminated by the illumination means, and the optical system. An image sensor (CCD) or the like that captures the captured image is provided, and the captured image signal is sent to a control unit (not shown).

The laminated body removal process implemented using the laser processing apparatus 6 mentioned above is demonstrated with reference to FIG. 7 and FIG.
In the laminated body removing step, the protective tape 3 attached to the front surface 2a of the wafer 2 constituting the laminated wafer 222 is peeled off, and a protective member is formed on the back surface of the plurality of second semiconductor devices 220 constituting the laminated wafer 222. 30 is attached, and the protective member 30 attached to the laminated wafer 222 is placed on the chuck table 61 of the laser processing apparatus 3 as shown in FIG. Then, the laminated wafer 222 is sucked and held on the chuck table 61 via the protective member 30 by operating a suction means (not shown). In the laminated wafer 222 held on the chuck table 61 in this way, the surface 2a of the wafer 2 on which the first semiconductor device 22 is formed is on the upper side.

  As described above, the chuck table 61 that sucks and holds the laminated wafer 222 is moved directly below the imaging unit 63 by a processing feed unit (not shown). When the chuck table 61 is positioned immediately below the image pickup means 63, an alignment operation for detecting a processing region to be laser processed of the wafer 2 constituting the laminated wafer 222 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) include a street 23 formed in a predetermined direction of the wafer 2 constituting the laminated wafer 222 and a condenser 622 of the laser beam irradiation unit 62 that irradiates a laser beam along the street 23. Image processing such as pattern matching is performed for alignment with the laser beam, and alignment of the laser beam irradiation position is performed. Similarly, alignment of the laser beam irradiation position is performed on the street 23 formed in the wafer 2 constituting the laminated wafer 222 and extending in a direction orthogonal to the predetermined direction.

  If the streets 23 formed in the predetermined direction of the wafer 2 constituting the laminated wafer 222 held on the chuck table 61 as described above are detected and alignment of the laser beam irradiation position is performed, FIG. As shown in (a), the chuck table 61 is moved to the laser beam irradiation region where the condenser 622 of the laser beam application means 62 for irradiating the laser beam is located, and the predetermined street 23 is positioned immediately below the condenser 622. At this time, as shown in FIG. 8A, the wafer 2 constituting the laminated wafer 222 is positioned so that one end of the street 23 (the left end in FIG. 8A) is located immediately below the condenser 622. It is done. Next, the chuck table 61 is irradiated with the arrow X1 in FIG. It is moved at a predetermined processing feed speed in the direction shown. When the other end of the street 23 (the right end in FIG. 8) reaches a position immediately below the condenser 622 as shown in FIG. 8B, the irradiation of the pulse laser beam is stopped and the movement of the chuck table 61 is stopped. To do. In this laminated body removing step, the condensing point P of the pulse laser beam is matched with the vicinity of the surface of the street 23. As a result, a laser processing groove 230 is formed along the street 23 in the laminated body 21 laminated on the surface of the substrate 20 of the wafer 2 constituting the laminated wafer 222 as shown in FIG. The laminated body 21 is removed along

In addition, the said laminated body removal process is performed on the following process conditions, for example.
Laser light source: YVO4 laser or YAG laser Wavelength: 355 nm
Output: 4W
Repetition frequency: 100 kHz
Condensing spot diameter: φ50μm
Processing feed rate: 100 mm / sec

The laminated body removing step described above is performed on all the streets 23 formed on the wafer 2 constituting the laminated wafer 222.
As described above, when the laminated body removing step is performed along all the streets 23 extending in a predetermined direction of the wafer 2 constituting the laminated wafer 222, the chuck table 61 is rotated 90 degrees to A laminated body removal process is implemented along each street 23 extended in the direction orthogonal to a predetermined direction. As a result, in the laminated body 21 laminated on the surface of the substrate 20 of the wafer 2 constituting the laminated wafer 222, the laser processed grooves 230 are formed along all the streets 23, and the laminated body 21 is removed along the streets 23. Is done.

  In addition, although a laminated body removal process may be implemented after implementing the device bonding process mentioned above, it may be implemented after implementing the said back surface grinding process, and it implements before implementing the said back surface grinding process. May be.

  When the device bonding step and the laminated body removing step are performed as described above, a wafer supporting step is performed in which the surface 2a of the wafer 2 constituting the laminated wafer 222 is attached to a dicing tape attached to an annular frame. . That is, the surface 2a of the wafer 2 constituting the laminated wafer 222 is adhered to the surface of the dicing tape T mounted on the annular frame F as shown in FIG. Then, the protective member 30 attached to the back surfaces of the plurality of second semiconductor devices 220 constituting the laminated wafer 222 is peeled off.

  Next, an individual semiconductor device in which the wafer 2 constituting the laminated wafer 222 is processed along the street 23 from the back surface 20b side of the substrate 20 and the second semiconductor device 220 is bonded to the back surface of the first semiconductor device 22. A wafer splitting process is carried out. A first embodiment of the wafer dividing step will be described with reference to FIGS. The first embodiment of the wafer dividing step is performed using a cutting apparatus shown in FIG. A cutting apparatus 7 shown in FIG. 10 includes a chuck table 71 having suction holding means, a cutting means 72 having a cutting blade 721, and an imaging means 73 for imaging a workpiece held on the chuck table 71. is doing. The chuck table 71 is moved in a cutting feed direction indicated by an arrow X in FIG. 10 by a cutting feed mechanism (not shown), and is moved in an index feeding direction indicated by an arrow Y by an index feeding mechanism (not shown). Further, the chuck table 71 can be rotated by a rotation mechanism (not shown). The imaging means 73 is arranged on the same line as the cutting blade 721 in the cutting feed direction indicated by the arrow X. In the illustrated embodiment, the image pickup means 73 is not only a normal image pickup device (CCD) for picking up an image with visible light, but also an infrared illumination means for irradiating the workpiece with infrared rays, and an infrared ray emitted by the infrared illumination means. And an imaging device (infrared CCD) that outputs an electrical signal corresponding to the infrared rays captured by the optical system, and sends the captured image signal to a control means (not shown).

A wafer dividing process performed using the cutting device 7 described above will be described with reference to FIGS.
That is, as shown in FIG. 10, the wafer support process described above is carried out on the chuck table 71 of the cutting device 7, and the laminate stuck to the surface of the dicing tape T mounted on the annular frame F as shown in FIG. A wafer 222 is placed. Then, the laminated wafer 222 is sucked and held on the chuck table 71 via the dicing tape T by operating a suction means (not shown). In FIG. 10, the annular frame F to which the dicing tape T is attached is not shown, but the annular frame F is held by appropriate frame holding means disposed on the chuck table 71. The chuck table 71 that sucks and holds the laminated wafer 222 in this way is positioned directly below the imaging means 73 by a cutting feed mechanism (not shown).

  When the chuck table 71 is positioned directly below the image pickup means 73, an alignment process for detecting an area to be cut of the wafer 2 constituting the laminated wafer 222 is executed by the image pickup means 73 and a control means (not shown). That is, the imaging unit 73 and a control unit (not shown) align the laser processing groove 230 formed along the street 23 formed in a predetermined direction of the wafer 2 constituting the laminated wafer 222 and the cutting blade 721. Perform alignment to do. That is, the imaging unit 73 images the laser processing groove 230 formed along the street 23 formed in the predetermined direction of the wafer 2 constituting the laminated wafer 222 and sends the image signal to a control unit (not shown). Then, the control means (not shown) executes an alignment process for positioning the cutting blade 721 at the center in the width direction of the laser processing groove 230 based on the image signal of the laser processing groove 230 sent from the imaging means 73. In addition, alignment is similarly performed on the laser processing grooves 230 formed along the streets 23 extending orthogonally to the predetermined direction of the wafer 2 constituting the laminated wafer 222 (alignment step). At this time, the laser processing groove 230 formed along the street 23 formed in the predetermined direction of the wafer 2 constituting the laminated wafer 222 is positioned on the lower side, but the imaging means 73 is infrared as described above. Since it includes an imaging means including an illuminating means, an optical system that captures infrared rays, and an imaging device (infrared CCD) that outputs an electrical signal corresponding to the infrared rays, a watermark is formed from the back side of the wafer 2 constituting the laminated wafer 222. The laser processing groove 230 formed along the street 21 can be imaged.

  As described above, the laser processing groove 230 formed along the street 23 formed on the wafer 2 constituting the laminated wafer 222 held on the chuck table 71 is detected, and the cutting region is aligned. Then, the chuck table 71 holding the laminated wafer 222 is moved to the cutting start position in the cutting area. At this time, as shown in FIG. 11, in the laminated wafer 222, one end (the left end in FIG. 11) of the street 23 to be cut (the laser processing groove 230 is formed) is positioned to the right by a predetermined amount from just below the cutting blade 721. So positioned.

  When the chuck table 71, that is, the laminated wafer 222 is positioned at the cutting start position in the cutting region in this way, the cutting blade 721 is cut and fed downward from the standby position indicated by the two-dot chain line in FIG. In FIG. 11A, it is positioned at a predetermined cutting feed position as indicated by a solid line. This cutting feed position is set at a position where the lower end of the cutting blade 721 reaches the dicing tape T attached to the front surface 20a (lower surface) of the wafer 2 constituting the laminated wafer 222 as shown in FIG. ing.

  Next, the cutting blade 721 is rotated at a predetermined rotational speed in the direction indicated by the arrow 721a in FIG. 11A, and the chuck table 71, that is, the laminated wafer 222 is predetermined in the direction indicated by the arrow X1 in FIG. Move at a cutting feed rate of. Then, as shown in FIG. 11B, the chuck table 71, that is, the laminated wafer 222 reaches the other end of the street 23 (the right end in FIG. 11B) until it is positioned to the left by a predetermined amount from just below the cutting blade 721. Then, the movement of the chuck table 71, that is, the laminated wafer 222 is stopped. By cutting and feeding the chuck table 71, that is, the laminated wafer 222 in this way, the wafer 2 constituting the laminated wafer 222 is formed along the laser processing groove 230 formed on the street 23 as shown in FIG. A dividing groove 231 reaching the surface 20a (the lower surface in FIG. 8B) is formed (cutting step). In this cutting process, since the surface 20a on the lower side of the wafer 2 constituting the laminated wafer 222 is adhered to the dicing tape T and there is no gap, no vibration is generated by cutting with the cutting blade 721. No chipping occurs. Further, in the laminate 21 laminated on the surface of the substrate 20 of the wafer 2, the laser processing grooves 230 are formed along the streets 23 and the laminate 21 is removed along the streets 23. Even if 2 is cut along the street 23, the laminate 21 does not peel off.

In addition, the said cutting process is performed on the following process conditions, for example.
Cutting blade: outer diameter 52mm, thickness 30μm
Cutting blade rotation speed: 40000 rpm
Cutting feed rate: 50 mm / sec

  The above-described cutting process is performed along all the streets 23 formed on the wafer 2 constituting the laminated wafer 222. As a result, the wafer 2 constituting the laminated wafer 222 was cut along the laser processing groove 230 formed in the street 23 and the second semiconductor device 220 was joined to the back surface of the first semiconductor device 22. Divided into individual semiconductor devices (wafer dividing step).

  When the dividing grooves 231 are formed along all the streets 23 extending in a predetermined direction of the wafer 2 constituting the laminated wafer 222 as described above, the chuck table 71 is rotated 90 degrees to A dividing groove 231 is formed along each street 23 extending in a direction orthogonal to the direction. As a result, the wafer 2 constituting the laminated wafer 222 was cut along the laser processing groove 230 formed in the street 23 and the second semiconductor device 220 was joined to the back surface of the first semiconductor device 22. Divided into individual semiconductor devices.

  As described above, by performing the wafer dividing step, the dividing grooves 231 are formed along all the streets 23 extending in a predetermined direction of the wafer 2 constituting the laminated wafer 222, and the back surface of the first semiconductor device 22 is formed. When the second semiconductor device 220 is separated into individual semiconductor devices configured by bonding, the first semiconductor device 22 (the second semiconductor device 220 is bonded to the back surface) is peeled from the dicing tape T. By picking up the semiconductor device 2A, the semiconductor device 2A in which the second semiconductor device 220 is bonded to the back surface of the first semiconductor device 22 as shown in FIG. 13 is obtained.

Next, a second embodiment of the wafer dividing process will be described with reference to FIGS. The second embodiment of the wafer dividing step is performed using a laser processing apparatus substantially similar to the laser processing apparatus 6 shown in FIG. Therefore, in the following explanation, the same reference numerals as those of the laser processing apparatus 6 are used for explanation.
In order to implement the second embodiment of the wafer dividing process, the wafer support process described above is performed on the chuck table 61 of the laser processing apparatus 6 as shown in FIG. 14, and the annular frame F is formed as shown in FIG. The laminated wafer 222 attached to the surface of the attached dicing tape T is placed. The laminated wafer 222 is sucked and held on the chuck table 61 via the dicing tape T by operating a suction means (not shown). In FIG. 14, the annular frame F on which the dicing tape T is mounted is omitted, but the annular frame F is held by appropriate frame holding means provided on the chuck table 61. The chuck table 61 that sucks and holds the laminated wafer 222 in this way is positioned directly below the imaging means 63 by a processing feed mechanism (not shown).

  When the chuck table 61 is positioned immediately below the image pickup means 63, an alignment process for detecting an area to be cut of the wafer 2 constituting the laminated wafer 222 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) align the laser processing groove 230 formed along the street 23 formed in a predetermined direction of the wafer 2 constituting the laminated wafer 222 and the condenser 622. Perform alignment to perform. That is, the imaging unit 63 images the laser processing groove 230 formed along the street 23 formed in the predetermined direction of the wafer 2 constituting the laminated wafer 222 and sends the image signal to a control unit (not shown). Then, a control unit (not shown) executes an alignment process for positioning the condenser 622 at the center in the width direction of the laser processing groove 230 based on the image signal of the laser processing groove 230 sent from the imaging unit 63. In addition, alignment is similarly performed on the laser processing grooves 230 formed along the streets 23 extending orthogonally to the predetermined direction of the wafer 2 constituting the laminated wafer 222 (alignment step). At this time, although the laser processing groove 230 formed along the street 23 formed in the wafer 2 constituting the laminated wafer 222 is positioned on the lower side, the imaging unit 63 is an optical device that captures infrared rays and infrared rays. It is formed along the street 23 through the back surface side of the wafer 2 constituting the laminated wafer 222 by using an imaging means constituted by an imaging device (infrared CCD) or the like that outputs an electrical signal corresponding to the system and infrared rays. The laser-processed groove 230 can be imaged.

  As described above, the laser processing groove 230 formed along the street 23 formed on the wafer 2 constituting the laminated wafer 222 held on the chuck table 61 is detected, and alignment of the laser beam irradiation position is performed. Then, as shown in FIG. 15 (a), the chuck table 61 is moved to the laser beam irradiation area where the condenser 622 of the laser beam application means 62 for irradiating the laser beam is located, and the predetermined street 23 is moved to the collector. It is positioned directly below 622. At this time, as shown in FIG. 15A, the wafer 2 constituting the laminated wafer 222 is positioned so that one end of the street 23 (the left end in FIG. 15A) is located immediately below the condenser 622. It is done. Next, the chuck table 61 of FIG. In (a), it is moved at a predetermined machining feed rate in the direction indicated by the arrow X1. Then, as shown in FIG. 15B, when the other end of the street 23 (the right end in FIG. 15) reaches a position directly below the condenser 622, the irradiation of the pulse laser beam is stopped and the movement of the chuck table 61 is stopped. (Laser cutting process). In this laser cutting step, the condensing point P of the pulse laser beam is matched with the vicinity of the rear surface 20b (upper surface) of the wafer 2 constituting the laminated wafer 222. As a result, as shown in FIG. 15C, the wafer 2 constituting the laminated wafer 222 reaches the surface 2a (the lower surface in FIG. 15C) along the laser processing groove 230 formed in the street 23. A dividing groove 232 is formed. In this laser cutting process, since the lower surface 2a of the wafer 2 constituting the laminated wafer 222 is adhered to the dicing tape T, debris generated by the irradiation of the laser beam adheres to the dicing tape T and is laminated. Debris does not adhere to the side surface of the second semiconductor device 220 bonded to the back surface of the substrate 20 of the wafer 2 constituting the wafer 222 (the top surface in FIG. 15C).

In addition, the said laser cutting process is performed on the following process conditions, for example.
Laser light source: YVO4 laser or YAG laser Wavelength: 355 nm
Output: 10W
Repetition frequency: 100 kHz
Condensing spot diameter: φ10μm
Processing feed rate: 100 mm / sec

  The laser cutting process described above is performed along the laser processing grooves 230 formed on all the streets 23 formed on the wafer 2 constituting the laminated wafer 222. As a result, the wafer 2 constituting the laminated wafer 222 was cut along the laser processing groove 230 formed in the street 23 and the second semiconductor device 220 was joined to the back surface of the first semiconductor device 22. Separated into individual semiconductor devices (wafer dividing step).

  If the wafer dividing step is performed as described above, the first semiconductor device 22 (the second semiconductor device 220 is bonded to the back surface) is peeled off from the dicing tape T and picked up, so that FIG. As shown, the semiconductor device 2A in which the second semiconductor device 220 is bonded to the back surface of the first semiconductor device 22 is obtained.

2: Wafer 21: Street 22: First semiconductor device 23: Device region 24: Peripheral surplus region 200: Wafer 220: Second semiconductor device 222: Laminated wafer 3: Protection member 4: Grinding device 41: Chuck of grinding device Table 42: Grinding means 424: Grinding wheel 5: Bonding device 51: Holding table 52: Suction hand 6: Laser processing device 61: Chuck table of laser processing device 62: Laser beam irradiation means 622: Condenser 7: Cutting device 71: Cutting device chuck table 72: Cutting means 721: Cutting blade F: Annular frame T: Dicing tape

Claims (6)

A method of manufacturing a semiconductor device comprising a second semiconductor device joined to the back surface of a first semiconductor device,
A back surface grinding step of grinding the back surface of the wafer substrate on which the plurality of first devices are formed by a laminate in which an insulating film and a functional film are laminated on the surface of the substrate to form a predetermined thickness;
A device bonding step of bonding the second semiconductor device to a predetermined position corresponding to the first semiconductor device on the back surface of the substrate of the wafer on which the first device is formed, to form a laminated wafer;
A laminate removing step of irradiating a laser beam along a street partitioning a plurality of devices of the wafer on which the first device is formed, and removing the laminate along the street;
A wafer supporting step of adhering the surface of the wafer constituting the laminated wafer subjected to the device bonding step and the laminated body removing step to a dicing tape attached to an annular frame;
Individual semiconductor devices processed along the street from the back side of the wafer substrate constituting the laminated wafer on which the wafer support step has been performed, and the second semiconductor device bonded to the back side of the first semiconductor device And a wafer dividing step to be separated into
A method for manufacturing a semiconductor device.   The method for manufacturing a semiconductor device according to claim 1, wherein the stacked body removing step is performed after the device bonding step is performed.   The method for manufacturing a semiconductor device according to claim 1, wherein the stacked body removing step is performed after the back surface grinding step is performed.   The method of manufacturing a semiconductor device according to claim 1, wherein the stacked body removing step is performed before the back surface grinding step.   5. The method of manufacturing a semiconductor device according to claim 1, wherein in the wafer dividing step, the wafer is cut along a street by a cutting blade from a back surface side of a wafer substrate constituting the laminated wafer.   5. The wafer dividing step according to claim 1, wherein the wafer forming the laminated wafer is irradiated with a laser beam along the street from the back side of the substrate of the wafer constituting the laminated wafer, and the wafer constituting the laminated wafer is divided along the street. The manufacturing method of the semiconductor device of description.

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