JP5426314B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention divides a wafer in which devices are formed in a plurality of regions partitioned by streets formed in a lattice shape on the surface into individual devices along the streets, and bonds the die bonding to the back surface of each device. The present invention relates to a method for manufacturing a semiconductor device to which a film is attached.

  For example, in a semiconductor device manufacturing process, devices such as IC and LSI are formed in a plurality of regions partitioned by division lines (streets) formed in a lattice shape on the surface of a semiconductor wafer having a substantially disk shape, Individual semiconductor devices are manufactured by dividing each region in which the devices are formed along the streets. A dicing apparatus is generally used as a dividing apparatus for dividing a semiconductor wafer, and the dicing apparatus cuts the semiconductor wafer along the street with a cutting blade having a thickness of about 20 μm. The semiconductor devices divided in this way are packaged and widely used in electric devices such as mobile phones and personal computers.

  Each of the divided semiconductor devices has a die bonding adhesive film called a die attach film having a thickness of 20 to 40 μm formed of a polyimide resin, an epoxy resin, an acrylic resin or the like on the back surface thereof. Bonding is performed by heating to a die bonding frame that supports the semiconductor device via an adhesive film. As a method of attaching the adhesive film for die bonding to the back surface of the semiconductor device, the adhesive film is attached to the back surface of the semiconductor wafer, the semiconductor wafer is attached to the dicing tape through the adhesive film, and then the semiconductor wafer By cutting along with the adhesive film with a cutting blade along the street formed on the front surface, a semiconductor device having the adhesive film mounted on the back surface is formed.

  In recent years, electric devices such as mobile phones and personal computers are required to be lighter and smaller, and thinner semiconductor devices are required. As a technique for dividing a semiconductor device thinner, a dividing technique called a so-called pre-dicing method has been put into practical use. In this tip dicing method, a dividing groove having a predetermined depth (a depth corresponding to the finished thickness of the semiconductor device) is formed along the street from the surface of the semiconductor wafer, and then a protective tape is applied to the surface of the semiconductor wafer. Then, by grinding the back surface of the semiconductor wafer, a dividing groove is exposed on the back surface and the semiconductor device is divided into individual semiconductor devices. The thickness of the semiconductor device can be processed to 50 μm or less.

  However, when a semiconductor wafer is divided into individual semiconductor devices by the tip dicing method, a dividing groove having a predetermined depth is formed along the street from the surface of the semiconductor wafer, and then a protective tape is attached to the surface of the semiconductor wafer. Then, since the back surface is ground and the dividing grooves are exposed on the back surface, an adhesive film for die bonding cannot be mounted on the back surface of the semiconductor wafer in advance. Therefore, when bonding to the die bonding frame that supports the semiconductor device by the first dicing method, the bonding agent must be inserted between the semiconductor device and the die bonding frame, and the bonding operation is performed smoothly. There is a problem that can not be.

  In order to solve such problems, an adhesive film for die bonding is attached to the back surface of the wafer divided into individual semiconductor devices by the prior dicing method, and the semiconductor device is attached to the dicing tape via the adhesive film. Then, the manufacturing method of the semiconductor device which expands a dicing tape and gives tension | tensile_strength to an adhesive film and fractures | ruptures an adhesive film along a division | segmentation groove | channel is proposed. (For example, refer to Patent Document 1.)

JP 2004-193241 A

Thus, in the semiconductor device manufacturing method disclosed in Patent Document 1, an adhesive film for die bonding is attached to the back surface of the wafer divided into individual semiconductor devices by the pre-dicing method. There is also an adhesive film at a position corresponding to the dividing groove formed between the devices. Therefore, after pasting the semiconductor device to the dicing tape through the adhesive film, if the dicing tape is expanded to give a tensile force to the adhesive film and the adhesive film is broken along the dividing groove, it corresponds to the dividing groove. Since the portion is broken in a state of protruding from the outer periphery of the semiconductor device, the protruding adhesive film adheres to the bonding pad formed on the surface of the semiconductor device, causing a conduction failure and lowering the quality of the semiconductor device. There is a problem.
In addition, when the dicing tape is expanded to apply a tensile force to the adhesive film, the adhesive film existing at a position corresponding to the dividing groove formed between adjacent semiconductor devices expands. In some cases, the semiconductor device may not be broken along the outer peripheral edge, and the semiconductor device cannot be picked up from the dicing tape.

  The present invention has been made in view of the above facts, and the main technical problem thereof is that the adhesive film attached to the back surface of the wafer can be reliably broken along the outer peripheral edge without protruding from the outer peripheral edge of the device. The object is to provide a method of manufacturing a semiconductor device.

In order to solve the above main technical problem, according to the present invention, a wafer in which devices are formed in a plurality of regions partitioned by a plurality of streets formed in a lattice shape on the surface is divided into individual devices along the streets. And a method for manufacturing a semiconductor device in which an adhesive film for die bonding is attached to the back surface of each device,
A split groove forming step of forming a split groove having a depth corresponding to the finished thickness of the device along the street from the surface side of the wafer;
A protective tape attaching step of attaching a protective tape that shrinks by applying heat to the surface of the wafer on which the divided grooves are formed;
A wafer dividing step of grinding the back surface of the wafer to which the protective tape is attached to expose the dividing grooves on the back surface, and dividing the wafer into individual devices;
A divided groove closing step of closing the divided grooves by applying heat to the protective tape adhered to the surface of the wafer on which the wafer dividing step has been performed to shrink the protective tape;
An adhesive film mounting step of mounting an adhesive film for die bonding on the back surface of the wafer subjected to the dividing groove closing step and supporting the adhesive film side with a dicing tape mounted on an annular frame;
After performing the adhesive film mounting step, the dicing tape is expanded to give a tensile force to the adhesive film, and the adhesive film breaking step of breaking the adhesive film along the outer peripheral edge of each device;
A pickup step in which the adhesive film breaking step is performed and a device on which the adhesive film broken along the outer periphery of the device is mounted is peeled off from the dicing tape and picked up.
A method for manufacturing a semiconductor device is provided.

  According to the present invention, a protective tape that is shrunk by applying heat to the surface of the wafer formed with a dividing groove having a depth corresponding to the finished thickness of the device along the street from the surface side of the wafer is attached, After carrying out the wafer dividing step, the adhesive tape is contracted by applying heat to the protective tape to close the dividing groove, and then the adhesive film mounting step and the adhesive film breaking step are carried out, so the dicing tape is expanded. When the adhesive film breaking process is performed, in which a tensile force is applied to the adhesive film and the adhesive film is broken along the outer peripheral edge of each device, the individual devices are brought close to each other and the dividing grooves are closed to close the grooves. The width is substantially zero (0), and by expanding the dicing tape, the individual devices are spread to form an interval. For this reason, the adhesive film adhered to the back surface of the wafer is accurately broken along the outer peripheral edge of the device without protruding from the outer peripheral edge of the device, and the extension of the adhesive film is restricted to extend along the outer peripheral edge of the device. Breaks reliably.

The perspective view which shows the semiconductor wafer as a wafer. Explanatory drawing of the division | segmentation groove | channel formation process in the manufacturing method of the device by this invention. Explanatory drawing of the masking tape sticking process in the manufacturing method of the device by this invention. Explanatory drawing of the wafer division | segmentation process in the manufacturing method of the device by this invention. Explanatory drawing of the division | segmentation groove | channel obstruction | occlusion process in the manufacturing method of the device by this invention. Explanatory drawing of the adhesive film mounting process in the manufacturing method of the device by this invention. Explanatory drawing which shows other embodiment of the adhesive film mounting process in the manufacturing method of the device by this invention. The perspective view of the tape expansion apparatus for implementing the adhesive film fracture | rupture process in the manufacturing method of the device by this invention. Explanatory drawing of the adhesive film fracture | rupture process in the manufacturing method of the device by this invention. Explanatory drawing of the pick-up process in the manufacturing method of the device by this invention. The perspective view of the semiconductor device manufactured by the manufacturing method of the device by this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a semiconductor device manufacturing method according to the invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a semiconductor wafer as a wafer. The semiconductor wafer 2 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 600 μm, and a plurality of streets 21 are formed in a lattice shape on the surface 2a. On the surface 2 a of the semiconductor wafer 2, devices 22 such as IC and LSI are formed in a plurality of regions partitioned by a plurality of streets 21 formed in a lattice shape. A procedure for dividing the semiconductor wafer 2 into individual semiconductor devices by the prior dicing method will be described.

  In order to divide the semiconductor wafer 2 into individual semiconductor devices by the tip dicing method, first, a predetermined depth along the street 21 formed on the surface 2a of the semiconductor wafer 2 (a depth corresponding to the finished thickness of each device). Are formed (divided groove forming step). In the illustrated embodiment, this dividing groove forming step is performed using a cutting device 3 shown in FIG. A cutting apparatus 3 shown in FIG. 2A is held by the chuck table 31 that holds a workpiece, cutting means 32 that cuts the workpiece held by the chuck table 31, and the chuck table 31. An image pickup means 33 for picking up an image of the workpiece is provided. The chuck table 31 is configured to suck and hold a workpiece, and is moved in a cutting feed direction indicated by an arrow X in FIG. 2A by an unillustrated cutting feed mechanism, and an unillustrated indexing feed mechanism. Can be moved in the index feed direction indicated by the arrow Y.

  The cutting means 32 includes a spindle housing 321 arranged substantially horizontally, a rotary spindle 322 rotatably supported by the spindle housing 321, and a cutting blade 323 mounted on the tip of the rotary spindle 322. The rotary spindle 322 is rotated in the direction indicated by the arrow 322a by a servo motor (not shown) disposed in the spindle housing 321. The imaging means 33 is attached to the tip of the spindle housing 321 and illuminates the workpiece, an optical system that captures an area illuminated by the illumination means, and an image captured by the optical system. An image pickup device (CCD) or the like for picking up images is provided, and the picked up image signal is sent to a control means (not shown).

  In order to perform the dividing groove forming process using the cutting device 3 described above, the back surface 2b side of the semiconductor wafer 2 is placed on the chuck table 31 as shown in FIG. By operating, the semiconductor wafer 2 is held on the chuck table 31. Therefore, the surface 2a of the semiconductor wafer 2 held on the chuck table 31 is on the upper side. In this way, the chuck table 31 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging means 33 by a cutting feed mechanism (not shown).

  When the chuck table 31 is positioned immediately below the image pickup means 33, an alignment operation for detecting a cutting region in which the division grooves are to be formed along the streets 21 of the semiconductor wafer 2 is executed by the image pickup means 33 and a control means (not shown). That is, the imaging unit 33 and a control unit (not shown) execute image processing such as pattern matching for aligning the street 21 formed in a predetermined direction of the semiconductor wafer 2 and the cutting blade 323, and cutting region Alignment is performed (alignment process). In addition, the alignment of the cutting area is similarly performed on the street 21 formed on the semiconductor wafer 2 and extending at right angles to the predetermined direction.

  When the alignment for detecting the cutting area of the semiconductor wafer 2 held on the chuck table 31 is performed as described above, the chuck table 31 holding the semiconductor wafer 2 is moved to the cutting start position of the cutting area. . Then, the cutting blade 323 is moved downward while rotating in the direction indicated by the arrow 322a in FIG. The cutting feed position is set such that the outer peripheral edge of the cutting blade 323 is a depth position (for example, 50 μm) corresponding to the finished thickness of the device from the surface of the semiconductor wafer 2. When the cutting blade 323 is cut and fed in this way, the chuck table 31 is cut and fed in the direction indicated by the arrow X in FIG. As shown in FIG. 5B, a dividing groove 210 having a depth (for example, 50 μm) corresponding to the finished thickness of the device is formed along the street 21 (dividing groove forming step).

  When the divided groove 210 having a predetermined depth is formed along the street 21 on the surface 2a of the semiconductor wafer 2 by performing the above-described divided groove forming step, the semiconductor wafer is formed as shown in FIGS. 3 (a) and 3 (b). The protective tape 4 that shrinks when heated is applied to the surface 2a of 2 (the surface on which the device 22 is formed) (protective tape attaching step). As a protective tape that shrinks when heated, an acrylic pressure-sensitive adhesive layer (on the surface of a sheet material made of stretched ethylene vinyl acetate copolymer having a thickness of 50 to 100 μm or a sheet made of polyethylene terephthalate having a thickness of 50 to 100 μm) A sheet material having a thickness of 10 to 20 μm can be used.

  Next, a wafer dividing step is performed in which the back surface 2b of the semiconductor wafer 2 to which the protective tape 4 is attached is ground, the dividing grooves 210 are exposed on the back surface 2b, and the semiconductor wafer 2 is divided into individual devices 22. This wafer dividing step is performed using a grinding apparatus 5 shown in FIG. A grinding apparatus 5 shown in FIG. 4A includes a grinding means 53 having a chuck table 51 for holding a workpiece and a grinding wheel 52 for grinding the workpiece held on the chuck table 51. It has. In order to carry out the wafer dividing step using the grinding apparatus 5, the protective tape 4 side of the semiconductor wafer 2 is placed on the chuck table 51 and the suction means (not shown) is operated to bring the semiconductor wafer 2 into the chuck table. Hold on 51. Therefore, the back surface 2b of the semiconductor wafer 2 held on the chuck table 51 is on the upper side. If the semiconductor wafer 2 is held on the chuck table 51 in this way, the grinding wheel 52 of the grinding means 53 is moved in the direction indicated by the arrow 52a while the chuck table 51 is rotated in the direction indicated by the arrow 51a, for example, at 300 rpm. For example, while rotating at 6000 rpm, the back surface 2b of the semiconductor wafer 2 is brought into contact with the surface and ground, and grinding is performed until the dividing groove 210 appears on the back surface 2b as shown in FIG. By grinding until the dividing grooves 210 are exposed in this way, the semiconductor wafer 2 is divided into individual devices 22 as shown in FIG. In addition, since the protective tape 4 is stuck on the surface of the plurality of divided devices 22, the form of the semiconductor wafer 2 is maintained without being separated.

  When the wafer dividing step described above is performed, the protective tape 4 is shrunk by applying heat to the protective tape 4 attached to the surface 2a of the semiconductor wafer 2 divided into individual devices 22, thereby dividing the dividing groove. A split groove closing step for closing 210 is performed. This dividing groove closing step is performed using a heating device 6 shown in FIG. The heating device 6 shown in FIG. 5A includes a holding table 61 that holds a wafer, and hot air supply means 62 that blows hot air on the wafer placed on the holding table 61. In order to perform the dividing groove closing process using the heating device 6, the back surface 2 b side of the semiconductor wafer 2 on which the wafer dividing process described above has been performed is placed on the holding table 61. Therefore, the protective tape 4 attached to the surface 2a of the semiconductor wafer 2 placed on the holding table 61 is on the upper side. When the semiconductor wafer 2 is placed on the holding table 61 in this way, the hot air supply means 62 is operated to protect the hot air of 80 to 100 ° C. from the surface 2 a of the semiconductor wafer 2. Spray toward tape 4. As a result, since the protective tape 4 that contracts when heated is contracted, the individual devices 22 divided by the dividing grooves 210 as shown in FIG. 5B are shown in FIG. 5C. As described above, the shrinking of the protective tape 4 causes them to approach each other to close the dividing groove 210, and the groove width becomes substantially zero (0).

  If the dividing groove closing step described above is performed, a dicing adhesive film is mounted on the back surface 2b of the semiconductor wafer 2 divided into individual devices 22 and the adhesive film side is mounted on an annular frame. An adhesive film mounting process to be supported by the tape is performed. That is, as shown in FIGS. 6A and 6B, the adhesive film 7 is attached to the back surface 2b of the semiconductor wafer 2 divided into individual devices 22. At this time, the adhesive film 6 is pressed and attached to the back surface 2b of the semiconductor wafer 2 while being heated at a temperature of 80 to 200 ° C. The adhesive film 7 is made of an epoxy resin and is made of a film material having a thickness of 20 μm. When the adhesive film 7 is attached to the back surface 2b of the semiconductor wafer 2 in this way, the adhesive film 7 side of the semiconductor wafer 2 attached with the adhesive film 7 is formed into an annular frame as shown in FIG. Adhere to the attached extensible dicing tape. Accordingly, the protective tape 4 attached to the surface of the semiconductor wafer 2 is on the upper side. Then, the protective tape 4 attached to the surface 2a of the semiconductor wafer 2 is peeled off.

Another embodiment of the adhesive film mounting process described above will be described with reference to FIG.
In the embodiment shown in FIG. 7, a dicing tape with an adhesive film in which the adhesive film 7 is attached in advance to the surface of the dicing tape T is used. That is, as shown in FIGS. 7 (a) and 7 (b), the adhesive film 7 attached to the surface of the dicing tape T having the outer peripheral portion attached so as to cover the inner opening of the annular frame F is individually applied. The rear surface 2b of the semiconductor wafer 2 divided into the devices 22 is mounted. At this time, the adhesive film 7 is pressed and attached to the back surface 2 b of the semiconductor wafer 2 while being heated at a temperature of 80 to 200 ° C. The dicing tape T is made of a polyolefin sheet having a thickness of 95 μm in the illustrated embodiment. When a dicing tape with an adhesive film is used in this way, the semiconductor with the adhesive film 7 attached by attaching the back surface 2b of the semiconductor wafer 2 to the adhesive film 7 adhered to the surface of the dicing tape T. The wafer 2 is supported by a dicing tape T mounted on an annular frame F. Then, as shown in FIG. 7B, the protective tape 4 adhered to the surface 2a of the semiconductor wafer 2 is peeled off.

  If the adhesive film mounting step described above is performed, the dicing tape T is expanded to apply a tensile force to the adhesive film 7, and the adhesive film breaking step of breaking the adhesive film 7 along the outer peripheral edge of each device 22 is performed. carry out. This adhesive film breaking step is carried out using a tape expansion device 8 shown in FIG. 8 includes a frame holding means 81 for holding the annular frame F, and a tape extending means for expanding the dicing tape T attached to the annular frame F held by the frame holding means 81. 82 and a pickup collet 83. The frame holding means 81 includes an annular frame holding member 811 and a plurality of clamps 812 as fixing means disposed on the outer periphery of the frame holding member 811. An upper surface of the frame holding member 811 forms a mounting surface 811a on which the annular frame F is placed, and the annular frame F is placed on the mounting surface 811a. The annular frame F placed on the placement surface 811 a is fixed to the frame holding member 811 by a clamp 812. The frame holding means 81 configured as described above is supported by the tape expanding means 82 so as to be able to advance and retreat in the vertical direction.

  The tape expansion means 82 includes an expansion drum 821 disposed inside the annular frame holding member 811. The expansion drum 821 has an inner diameter and an outer diameter that are smaller than the inner diameter of the annular frame F and larger than the outer diameter of the semiconductor wafer 2 attached to the dicing tape T attached to the annular frame F. The expansion drum 821 includes a support flange 822 at the lower end. The tape expansion means 82 in the illustrated embodiment includes support means 823 that can advance and retract the annular frame holding member 811 in the vertical direction. The support means 823 includes a plurality of air cylinders 823 a arranged on the support flange 822, and the piston rod 823 b is connected to the lower surface of the annular frame holding member 811. In this way, the support means 823 including the plurality of air cylinders 823a is configured such that the annular frame holding member 811 has a reference position where the mounting surface 811a is substantially flush with the upper end of the expansion drum 821, as shown in FIG. Then, as shown in FIG. 9 (b), it is moved in the vertical direction between the extended positions below the upper end of the expansion drum 821 by a predetermined amount.

  With reference to FIG. 9, an adhesive film breaking step performed using the tape expansion device 8 configured as described above will be described. That is, the annular frame F on which the dicing tape T to which the adhesive film 7 side of the semiconductor wafer 2 (divided into individual devices 22 along the street 21) is attached is attached to the annular frame F shown in FIG. As shown in FIG. 4, the frame is held on the mounting surface 811a of the frame holding member 811 constituting the frame holding means 81 and fixed to the frame holding member 811 by the clamp 812 (frame holding step). At this time, the frame holding member 811 is positioned at the reference position shown in FIG. Next, the plurality of air cylinders 823a as the supporting means 823 constituting the tape extending means 82 are operated to lower the annular frame holding member 811 to the extended position shown in FIG. 9B. Accordingly, the annular frame F fixed on the mounting surface 811a of the frame holding member 811 is also lowered, so that the dicing tape T mounted on the annular frame F is an expansion drum as shown in FIG. Expansion is performed in contact with the upper edge of 821 (tape expansion process). As a result, the tensile force acts radially on the adhesive film 7 adhered to the dicing tape T. Thus, when a tensile force acts on the adhesive film 7 in a radial manner, the semiconductor wafer 2 is divided into individual devices 22 along the planned dividing line 21, so that the space between the individual devices 22 is widened and a space S is formed. The For this reason, since a tensile force acts on the adhesive film 7, the adhesive film 7 is broken.

  When this adhesive film breaking step is performed, the above-described split groove closing step is performed, whereby the individual devices 22 approach each other and the split groove 210 closes as shown in FIG. 9C. The groove width is substantially zero (0), and by performing the tape expansion step, as shown in FIG. For this reason, the adhesive film 7 is accurately broken along the outer peripheral edge of the device 22 without protruding from the outer peripheral edge of the device 22, and the extension of the adhesive film 7 is limited, so that the adhesive film 7 is reliably broken along the outer peripheral edge of the device 22. Is done.

  Next, as shown in FIG. 10, the pick-up collet 83 is operated to adsorb the device 22 (with the adhesive film 7 attached to the back surface), peeled off from the dicing tape T, and picked up. Thus, the semiconductor device 22 in which the adhesive film 7 accurately broken along the outer peripheral edge of the device 22 is adhered to the back surface is obtained. In the pickup process, as described above, the gap S between the individual devices 22 to which the adhesive film 6 is attached is widened, so that the pickup can be easily performed without contacting the adjacent devices 22.

2: Semiconductor wafer 21: Street 210: Cutting groove 3: Cutting device 31: Chuck table of cutting device 32: Cutting means 321: Cutting blade 4: Protection tape 5: Grinding device 51: Chuck table of grinding device 53: Grinding device 6 : Heating device 7: Adhesive film 8: Tape expansion device 81: Frame holding means 82: Tape expansion means 83: Pickup collet F: Ring frame T: Dicing tape

Claims (1)

A wafer having devices formed in a plurality of regions partitioned by a plurality of streets formed in a lattice pattern on the front surface is divided into individual devices along the streets, and an adhesive film for die bonding is provided on the back surface of each device. A method of manufacturing a semiconductor device to be mounted,
A split groove forming step of forming a split groove having a depth corresponding to the finished thickness of the device along the street from the surface side of the wafer;
A protective tape attaching step of attaching a protective tape that shrinks by applying heat to the surface of the wafer on which the divided grooves are formed;
A wafer dividing step of grinding the back surface of the wafer to which the protective tape is attached to expose the dividing grooves on the back surface, and dividing the wafer into individual devices;
A divided groove closing step of closing the divided grooves by applying heat to the protective tape adhered to the surface of the wafer on which the wafer dividing step has been performed to shrink the protective tape;
An adhesive film mounting step of mounting an adhesive film for die bonding on the back surface of the wafer subjected to the dividing groove closing step and supporting the adhesive film side with a dicing tape mounted on an annular frame;
After performing the adhesive film mounting step, the dicing tape is expanded to give a tensile force to the adhesive film, and the adhesive film breaking step of breaking the adhesive film along the outer peripheral edge of each device;
A pickup step in which the adhesive film breaking step is performed and a device on which the adhesive film broken along the outer periphery of the device is mounted is peeled off from the dicing tape and picked up.
A method for manufacturing a semiconductor device.

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