JP2011091239A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device with an adhesive sheet whose steps are not made complicated and which neither breaks the semiconductor device nor generates a defect in post-steps. <P>SOLUTION: The method of manufacturing the semiconductor device having the adhesive sheet arranged on a reverse surface includes a step of forming V grooves on a top surface side of a semiconductor wafer along predetermined division lines of the semiconductor wafer; a step of arranging a protective member on the top surface side of the semiconductor wafer having the V groove formed; a step of grinding the reverse surface side of the semiconductor wafer until the semiconductor wafer has a prescribed thickness; an adhesive sheet and expand sheet sticking step of sticking the adhesive sheet and an expand sheet on the reverse surface side of the ground semiconductor wafer in order; and a dividing step of dividing the semiconductor wafer and adhesive sheet into individual semiconductor devices along the predetermined division lines from V vertexes of the V grooves as starting points by expanding the expand sheet after removing the protective member from the top surface of the semiconductor wafer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device in which an adhesive sheet is disposed on the back surface.

  In recent semiconductor device technology, a stacked package in which a plurality of semiconductor devices such as MCP (Multi Chip Package) and SiP (System in Package) are stacked is effectively used to achieve high density and miniaturization of the device. It's being used.

  In the semiconductor device constituting such a stacked package, a die bonding adhesive sheet called DAF (Die Attach Film) is pasted on the back surface, and the laminated state of the semiconductor devices is held by this adhesive sheet. This adhesive sheet is widely used as a substitute for an adhesive such as silver paste resin that has been conventionally used when mounting a semiconductor device (chip) on a lead frame.

  A semiconductor device having an adhesive sheet attached to the back surface is manufactured by the following method. First, the back surface of a semiconductor wafer having a semiconductor device formed in each region partitioned by a plurality of division lines on the surface is ground and thinned.

  After that, an adhesive sheet is applied to the back surface of the thinned semiconductor wafer, and then the semiconductor wafer is cut along the planned dividing line with a cutting blade of a cutting device, and the adhesive sheet is also cut and divided to form the back surface. A semiconductor device provided with an adhesive sheet is manufactured.

  However, when the semiconductor wafer and the adhesive sheet are cut with the cutting blade, the adhesive sheet gets entangled with the cutting blade, causing the cutting blade to become clogged, and the semiconductor device formed by cutting the semiconductor wafer is chipped or cracked. Such defects will occur. In addition, whisker-like burrs are generated in the adhesive sheet, causing disconnection during wire bonding.

  On the other hand, in recent years, a so-called tip dicing method proposed in Japanese Patent Application Laid-Open No. 11-40520 has been widely adopted as a technique that enables manufacture of a semiconductor device that is smaller and thinner.

  In the first dicing method, a cutting groove having a depth reaching the thickness of the semiconductor device is formed on the surface of the semiconductor wafer along the division line, and then a protective member such as a protective tape is disposed on the surface of the semiconductor wafer.

  Thereafter, the back surface of the semiconductor wafer is ground and thinned to a predetermined thickness (the thickness of the semiconductor device to be formed), and the semiconductor wafer is divided into individual chips by exposing the cutting grooves to the back surface of the semiconductor device. .

  Each of the divided chips is integrally supported by a protective member, and an adhesive sheet such as DAF is disposed on the back side of the semiconductor wafer in this state. Thereafter, the adhesive sheet is cut to remove the surface protection member, thereby forming a semiconductor device in which the adhesive sheet is disposed on the back surface.

  For example, in Japanese Patent Application Laid-Open No. 61-112345, a semiconductor device having an adhesive sheet disposed on the back surface is formed by a tip dicing method using a cutting blade having a rectangular cross section. In one embodiment disclosed in this publication, after forming a cutting groove, an area not reaching the cutting groove of the semiconductor wafer is removed by grinding, and an adhesive sheet and an expanding sheet are sequentially laminated on the back surface, and then the expanded The semiconductor wafer is divided into individual chips by expanding the sheet.

JP 11-40520 A JP 61-112345 A

  However, in such a cutting groove having a flat bottom surface formed by using a cutting blade having a rectangular cross section, the dividing starting point at the time of dividing the wafer is not determined and the dividing property is very poor. Furthermore, the division starting point differs for each cutting groove, the outer diameter size of the divided semiconductor devices varies, and the division cracks run outside the region corresponding to the division line in the thickness direction of the semiconductor wafer, damaging the semiconductor device. There is a risk of letting you.

  On the other hand, in another embodiment disclosed in Japanese Patent Application Laid-Open No. 61-112345, after forming the cutting groove with a cutting blade having a rectangular cross section, the region reaching the cutting groove of the semiconductor wafer is removed by grinding, After laminating an adhesive sheet and an expanding sheet in order on the back surface, the expanding sheet is expanded to divide the semiconductor wafer.

  However, when the cutting groove is formed by using a cutting blade having a rectangular cross section and the area reaching the cutting groove of the semiconductor wafer is removed by grinding, each chip formed by dividing the semiconductor wafer is formed. An interval equivalent to the thickness of the cutting blade is formed between them. That is, the semiconductor wafer divided into a plurality of chips is in a state of being disposed on the adhesive sheet and the expanding sheet with a gap equivalent to the thickness of the cutting blade between the chips.

  The area of the adhesive sheet corresponding to the gap between the chips becomes an expandable area that is expanded by expansion of the expanded sheet. Therefore, even if the expanding sheet is expanded in this state, the adhesive sheet is very difficult to break because the stretchable area is wide compared to the case where there is no gap between the chips, and it is very difficult to break the adhesive sheet. It is necessary to give a large expansion force.

  Furthermore, even if the adhesive sheet is broken by applying a very large expansion force, the adhesive sheet protrudes from the outer periphery of the manufactured semiconductor device because the starting point of the adhesive sheet is an arbitrary point in the gap between the chips. It becomes a state.

  As described above, in the semiconductor device in which the adhesive sheet protrudes from the outer periphery, the protruded adhesive sheet is warped and adheres to the surface of the semiconductor device, which causes a wire bonding defect in a subsequent wire bonding process.

  Therefore, a method of cutting only the adhesive sheet using, for example, a cutting apparatus or a laser processing apparatus after dividing the semiconductor wafer by the prior dicing method and attaching the adhesive sheet is also conceivable. However, in this method, the process becomes complicated, and the adhesive sheet must be cut through the gaps between the chips formed by dividing the semiconductor wafer, and the adhesive sheet protrudes from the outer periphery of the semiconductor device. It is extremely difficult to perform the cutting process so that there is no problem.

  The present invention has been made in view of these points, and the object of the present invention is to cause defects in the subsequent process without complicating the process and without causing damage to the semiconductor device. It is providing the manufacturing method of the semiconductor device with an adhesive sheet which does not have a thing.

  According to the present invention, there is provided a semiconductor device manufacturing method in which an adhesive sheet is disposed on the back surface, wherein a V-groove forming step of forming a V-groove on the front surface side of the semiconductor wafer along a predetermined division line of the semiconductor wafer; A protective member disposing step of disposing a protective member on the front surface side of the semiconductor wafer in which the V-groove is formed, a back surface grinding step of grinding the back surface side of the semiconductor wafer to form the semiconductor wafer to a predetermined thickness, and grinding An adhesive sheet and an expand sheet adhering step for adhering an adhesive sheet and an expand sheet in order to the back side of the semiconductor wafer, and removing the protective member from the surface of the semiconductor wafer, and then expanding the expand sheet and the semiconductor wafer Dividing the adhesive sheet into individual semiconductor devices along the scheduled dividing line starting from the V apex of the V groove The method of manufacturing a semiconductor device, characterized by comprising a step, is provided.

  Preferably, in the V groove forming step, a V groove having a depth reaching a predetermined thickness is formed. In the back surface grinding step, the back surface side of the semiconductor wafer is ground to expose the V apex of the V groove on the back surface side of the semiconductor wafer.

  According to the present invention, since the semiconductor wafer is divided starting from the V apex of the V groove formed on the surface, the divided crack does not protrude from the outside of the region corresponding to the planned dividing line in the thickness direction of the wafer. There is no risk of damage. Since no gap is formed between the chips and there is no stretchable region of the adhesive sheet, the adhesive sheet can be easily divided by expanding the expanding sheet.

  In the dividing step, both the semiconductor wafer and the adhesive sheet are divided starting from the V apex of the V groove, so that the adhesive sheet is prevented from protruding from the outer periphery of the semiconductor device, and a wire bonding defect occurs in the subsequent wire bonding process. I will not let you.

It is a surface side perspective view of a semiconductor wafer. It is a flowchart which shows the manufacturing method of the semiconductor device of this invention. It is explanatory drawing of a V-groove formation step. It is a figure which shows the cutting blade used for a V-groove formation step. It is sectional drawing of the semiconductor wafer in which the V-groove formation step was implemented. It is a perspective view which shows a mode that a protective tape is stuck on the surface of a semiconductor wafer. It is sectional drawing of the state by which the protective tape was stuck on the surface of the semiconductor wafer. FIG. 8A is a perspective view of the back grinding step, and FIG. 8B is a side view thereof. It is sectional drawing of the semiconductor wafer after a back surface grinding step. It is another cross-sectional view of the semiconductor wafer after the back grinding step. FIG. 11A is a cross-sectional view of a semiconductor wafer in a state where an adhesive sheet is disposed on the back surface, and FIG. 11B is a cross-sectional view of the semiconductor wafer in a state where an expanding sheet is disposed on the adhesive sheet. . It is sectional drawing which shows a mode that a protective tape is removed. It is a perspective view of a dividing device. It is explanatory drawing of a semiconductor wafer division | segmentation step. FIG. 15A is a cross-sectional view in a state where the expanding sheet is expanded, and FIG. 15B is a cross-sectional view in a state where the expanding sheet is expanded and the semiconductor wafer and the adhesive sheet are divided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, on the surface of the semiconductor wafer 2, a first planned division line (street) S1 and a second planned division line S2 are formed orthogonal to each other, A device D is formed in each of a plurality of regions partitioned by the second scheduled division line S2.

  Referring to FIG. 2, a flowchart of a method for manufacturing a semiconductor device according to an embodiment of the present invention is shown. In the semiconductor device manufacturing method of this embodiment, first, in step S10, V-grooves are formed along the scheduled division lines S1 and S2 on the surface side of the semiconductor wafer. The V groove is formed by the cutting means 12 of a cutting apparatus as shown in FIG.

  A spindle 14 that is rotationally driven by a motor (not shown) is rotatably accommodated in a spindle housing 20 of the spindle unit 18 of the cutting means 12, and a cutting blade 16 is attached to the tip of the spindle 14.

  In the V groove forming step, a cutting blade 16 having a V shape 22 at the tip is used as shown in FIG. Alternatively, as shown in FIG. 4B, a cutting blade 16A having an inclined surface 24 on one side is used.

  In the V-groove forming step, the V-groove may be formed by a known scriber instead of the cutting blades 16 and 16A having a V-shaped tip. When the cutting blades 16 and 16A are used, it is preferable to perform machining while correcting the tip shapes of the cutting blades 16 and 16A by electric discharge machining.

  As shown in FIG. 3, the semiconductor wafer 2 is supported by the annular frame F via a dicing tape T which is an adhesive tape. When the semiconductor wafer 2 is sucked and held by a chuck table (not shown), the semiconductor wafer 2 is moved in the X-axis direction, and the spindle unit 18 is lowered while the cutting blade 16 is rotated at a high speed, the aligned first division schedule The line S1 is cut to form a V-groove 26 having a predetermined depth.

  By performing cutting while indexing the cutting blade 16 in the Y-axis direction in increments of street pitches stored in the memory, the V-grooves 26 are formed in all the division planned lines S1 in the same direction. Further, when the same cutting as described above is performed after the chuck table is rotated 90 degrees, the V-groove 26 is formed along the second scheduled division line S2. A cross-sectional view of the semiconductor wafer 2 with the V-groove 26 formed on the surface is shown in FIG. Reference numeral 26 a denotes the V apex of the V groove 26.

  After completion of the V-groove forming step, a protective member 28 such as a protective tape is attached to the surface 2a of the semiconductor wafer 2 as shown in FIG. 6 (step S11). FIG. 7 shows a cross-sectional view of the semiconductor wafer 2 with a protective member attached to the surface.

  After the protective member 28 is adhered to the surface of the semiconductor wafer 2 as described above, a back surface grinding step for grinding the back surface 2b of the semiconductor wafer 2 is performed (step S12). In this back grinding step, a grinding unit 30 of a grinding apparatus as shown in FIG. 8 is used. FIG. 8A is a perspective view showing the relationship between the semiconductor wafer 2 held on the chuck table 46 and the grinding unit 30, and FIG. 8B shows a side view thereof.

  The housing 32 of the grinding unit 30 houses a spindle 34 that is rotationally driven by a motor 38, and a wheel mount 36 is fixed to the tip of the spindle 34.

  A grinding wheel 40 is detachably attached to the wheel mount 36. The grinding wheel 40 includes a wheel base 42 and a plurality of grinding wheels 44 that are annularly disposed on the wheel base 42.

  In the back surface grinding step of step S12, the protection member 28 is sucked and held by the chuck table 46 to expose the back surface of the semiconductor wafer 2. Then, while rotating the chuck table 46 in the direction of arrow a at, for example, 300 rpm, the grinding wheel 40 is rotated in the direction of arrow b at, for example, 6000 rpm, and a grinding unit moving mechanism (not shown) is operated to move the grinding wheel 44 to the back surface of the wafer 2. Contact 2b.

  The grinding wheel 40 is ground and fed by a predetermined amount at a predetermined grinding feed speed, and the wafer 2 is ground. The wafer 2 is ground to a predetermined thickness while measuring the thickness of the wafer 2 with a contact or non-contact thickness gauge.

  FIG. 9 shows a cross-sectional view of the semiconductor wafer that has undergone the back grinding step. In the V-groove forming step of step S10, the V-groove 26 having a depth reaching a predetermined thickness is formed, and in the back surface grinding step, the back surface side of the wafer 2 is ground as shown in FIG. The V apex 26 a may be exposed on the back surface 2 b of the wafer 2.

  After performing the back surface grinding step, the process proceeds to step S13, and an adhesive sheet and expanded sheet disposing step for sequentially disposing the adhesive sheet 48 and the expanded sheet 54 on the back surface 2b of the semiconductor wafer 2 are performed.

  That is, an adhesive sheet 48 such as DAF is attached to the back surface 2b of the semiconductor wafer 2 as shown in FIG. 11A, and an expandable sheet 54 having ductility as shown in FIG. Affix.

  In the adhesive sheet and expanded sheet disposing step, the adhesive sheet and the expanded sheet may be attached in this order, or a sheet in which the adhesive sheet and the expanded sheet are integrated may be used.

  Next, the protective member 28 is peeled off from the surface 2a of the semiconductor wafer 2 as shown in FIG. 12, and then the dividing step of Step S14 is performed. In order to carry out this dividing step, for example, a dividing device 60 as shown in FIG. 13 is used.

  The dividing device 60 includes a frame holding unit 62 that holds the annular frame 50 and a tape expansion unit 64 that extends the expanded sheet 54 attached to the annular frame 50 held by the frame holding unit 62.

  The frame holding means 62 includes an annular frame holding member 66 and a plurality of clamps 68 as fixing means arranged on the outer periphery of the frame holding member 66. An upper surface of the frame holding member 66 forms a mounting surface 66a on which the annular frame 50 is mounted, and the annular frame 50 is mounted on the mounting surface 66a.

  The annular frame 50 placed on the placement surface 66 a is fixed to the frame holding member 66 by a clamp 68. The frame holding means 62 configured as described above is supported by the tape extending means 64 so as to be movable in the vertical direction.

  The tape expansion means 64 includes an expansion drum 70 disposed inside the annular frame holding member 66. The expansion drum 70 has an inner diameter that is smaller than the inner diameter of the annular frame 50 and larger than the outer diameter of the semiconductor wafer 2 attached to the expanded sheet 54 attached to the annular frame 50.

  The expansion drum 70 has a support flange 72 formed integrally with the lower end thereof. The tape expanding means 64 further includes driving means 74 that moves the annular frame holding member 66 in the vertical direction. The driving means 74 is composed of a plurality of air cylinders 76 disposed on the support flange 72, and the piston rod 78 is connected to the lower surface of the frame holding member 66.

  The drive means 74 composed of a plurality of air cylinders 76 has an annular frame holding member 66 with a predetermined amount from the reference position where the mounting surface 66a is substantially flush with the upper end of the expansion drum 70, and the upper end of the expansion drum 70. Move vertically between lower expansion positions.

  A semiconductor wafer dividing step performed using the dividing apparatus 60 configured as described above will be described with reference to FIGS. 14 (A) and 14 (B). As shown in FIG. 14A, the annular frame 50 that supports the semiconductor wafer 2 via the adhesive sheet 48 and the expanding sheet 54 is placed on the placement surface 66 a of the frame holding member 66, and is clamped by the clamp 68. The frame holding member 66 is fixed. At this time, the frame holding member 66 is positioned at a reference position where the mounting surface 66 a is substantially the same height as the upper end of the expansion drum 70.

  Next, the air cylinder 76 is driven to lower the frame holding member 66 to the extended position shown in FIG. As a result, the annular frame 50 fixed on the mounting surface 66a of the frame holding member 66 is also lowered, so that the expanding sheet 54 attached to the annular frame 50 abuts against the upper end edge of the expansion drum 70 and mainly. Expanded radially.

  As a result, a tensile force acts radially on the semiconductor wafer 2 and the adhesive sheet 48 that are adhered to the expanding sheet 54. In this way, when a radial tensile force acts on the semiconductor wafer 2 and the adhesive sheet 48, the semiconductor wafer 2 and the adhesive sheet 48 are separated from each other by using the V apex 26a of the V groove 26 formed in the semiconductor wafer 2 as a division starting point. It is broken along S2 and divided into individual semiconductor chips 4 with adhesive sheets as shown in FIG.

  As shown in FIG. 10, when the back surface 2b of the semiconductor wafer 2 is ground and the V apex 26a of the V groove 26 is exposed on the back surface, the semiconductor wafer 2 is already divided into individual chips. When a tensile force is applied to the expanding sheet 54, only the adhesive sheet 48 is broken along the planned dividing lines S1 and S2 with the V apex 26a of the V groove 26 as the dividing starting point.

2 Semiconductor wafer 16, 16A Cutting blade 22 V shape 24 Slope 26 V groove 26a V apex 28 Protective member 30 Grinding unit 40 Grinding wheel 46 Chuck table 48 Adhesive sheet 54 Expanding sheet 60 Dividing device 62 Frame holding means 64 Tape expanding means 66 Frame holding member 70 Expansion drum

Claims (2)

A method of manufacturing a semiconductor device having an adhesive sheet disposed on the back surface,
A V-groove forming step of forming a V-groove on the front surface side of the semiconductor wafer along a planned division line of the semiconductor wafer;
A protective member disposing step of disposing a protective member on the surface side of the semiconductor wafer in which the V-groove is formed;
A back grinding step of grinding the back side of the semiconductor wafer to form the semiconductor wafer to a predetermined thickness;
An adhesive sheet and an expanded sheet adhering step for sequentially adhering an adhesive sheet and an expanded sheet to the back side of the ground semiconductor wafer;
The protective member is removed from the surface of the semiconductor wafer, and then the expanded sheet is expanded so that the semiconductor wafer and the adhesive sheet are separated into individual semiconductor devices along the planned dividing line starting from the V apex of the V groove. A splitting step to split;
A method for manufacturing a semiconductor device, comprising: In the V groove forming step, the V groove having a depth reaching the predetermined thickness is formed,
2. The method of manufacturing a semiconductor device according to claim 1, wherein, in the back surface grinding step, the back surface side of the semiconductor wafer is ground to expose the V apex of the V groove on the back surface side of the semiconductor wafer.

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