JP5944581B2 - Semiconductor wafer grinding apparatus, semiconductor wafer manufacturing method, and semiconductor wafer grinding method - Google Patents

Description

  The present invention relates to a semiconductor wafer grinding apparatus, a semiconductor wafer manufacturing method, and a semiconductor wafer grinding method.

  In the semiconductor device manufacturing process, a plurality of regions are defined on the main surface of a semiconductor wafer by grid-like dividing lines, and devices such as ICs and LSIs are formed in these regions. Then, the semiconductor wafer is cut along the dividing lines, whereby the semiconductor wafer is divided into individual semiconductor chips (devices). Before the semiconductor wafer is divided along the dividing line, the surface opposite to the main surface is ground to a predetermined thickness by a grinding device (see, for example, Patent Document 1).

  FIG. 7 is a side view of a conventional semiconductor wafer grinding apparatus. As shown in FIG. 7, the conventional semiconductor wafer grinding apparatus includes a stage 101 that rotates a semiconductor wafer W and a grinding wheel 102 that faces the stage 101. The grinding wheel 102 has a slightly smaller diameter than the semiconductor wafer W, and a plurality of grinding stones 103 are provided along the peripheral edge of the surface facing the stage 101. The semiconductor wafer W is fixed on the stage 101, the stage 101 is rotated around the axis, and the grinding wheel 103 is pressed against the surface to be ground Wa of the semiconductor wafer W while the grinding wheel 102 is rotated around the central axis. Wa is lapped (ground). Thereafter, the surface to be ground Wa is etched to remove processing distortion, and then the surface to be ground Wa is polished to be finished into a mirror surface.

JP-A-10-156679

  The conventional semiconductor wafer grinding apparatus has a problem that the polishing process takes time. The problem will be described with reference to FIG. FIG. 8 is a schematic view of a surface to be ground Wa of a semiconductor wafer W ground by a conventional semiconductor wafer grinding apparatus.

  In the conventional semiconductor wafer grinding apparatus, since the grindstone 103 moves so as to draw a spiral trajectory around the center of the surface to be ground Wa, a fine spiral grinding groove Wb is generated on the surface to be ground Wa. There is a case. In that case, in the polishing process, in order to erase the grinding groove Wb, polishing with diamond abrasive grains must be performed before polishing with the polishing slurry. Therefore, compared with the case where the grinding groove Wb does not occur on the surface to be ground Wa, there is a problem that the time of the polishing process becomes longer and the productivity of the semiconductor wafer W is lowered.

  The present invention has been devised in view of the above problems, and its purpose is to suppress the generation of grinding grooves on the surface to be ground of a semiconductor wafer and to improve the productivity of the semiconductor wafer, A semiconductor wafer manufacturing method and a semiconductor wafer grinding method are provided.

  According to a first aspect of the present invention, there is provided a semiconductor wafer grinding apparatus for grinding a surface to be ground of a semiconductor wafer, a grinding wheel, first driving means for rotationally driving the grinding wheel around a central axis, and the semiconductor wafer. A wafer support that is rotatable about an axis that is parallel to the center axis of the grinding wheel and that is eccentric with respect to the center axis, and second driving means that rotationally drives the wafer support, The grinding wheel includes a plurality of grindstones provided on a main surface facing the wafer support, and the wafer support is configured such that the surface to be ground of the semiconductor wafer faces the main surface of the grinding wheel. The semiconductor wafer is supported, and each of the plurality of grindstones extends radially from the center of the grinding wheel and crosses the surface to be ground of the semiconductor wafer. It has been.

  According to the semiconductor wafer grinding apparatus according to the first aspect, the grinding wheel moves in parallel with the surface to be ground in a state of crossing the surface to be ground of the semiconductor wafer and grinds the surface to be ground. Can be suppressed. Therefore, it is not necessary to perform polishing with diamond abrasive grains, and the productivity of the semiconductor wafer can be improved.

  In one embodiment, the wafer support is formed to support a plurality of the semiconductor wafers. In this case, the plurality of semiconductor wafers can be ground simultaneously, so that the semiconductor wafer productivity is improved.

  In one embodiment, the semiconductor wafer grinding apparatus includes a plurality of the wafer supports. In this case, since a plurality of semiconductor wafers can be ground simultaneously, the productivity of the semiconductor wafer is improved.

  In addition, the second aspect of the present invention includes a cutting step of cutting a ingot to obtain a semiconductor wafer, a lapping step for grinding the ground surface of the semiconductor wafer, and a polishing step for polishing the ground surface. In the lapping step, the semiconductor wafer grinding apparatus according to the first aspect is used to grind the surface to be ground while rotating the grinding wheel and the wafer support.

  According to the method for manufacturing a semiconductor wafer according to the second aspect, it is possible to suppress the generation of grinding grooves on the surface to be ground of the semiconductor wafer in the lapping step. Therefore, it is not necessary to perform polishing with diamond abrasive grains in the polishing step, and the productivity of the semiconductor wafer is improved.

  In the lapping step, it is preferable to grind the surface to be ground while rotating the grinding wheel and the wafer support in the same direction. This is because an excessive force is less likely to be applied to the surface to be ground as compared with the case where the grinding wheel and the wafer support rotate in the opposite direction, so that the surface to be ground can be finished beautifully.

  According to a third aspect of the present invention, there is provided a semiconductor wafer grinding method using the semiconductor wafer grinding apparatus according to the first aspect, wherein the grinding object is rotated while rotating the grinding wheel and the wafer support. A semiconductor wafer grinding method for grinding a surface.

  According to the semiconductor wafer grinding method of the third aspect, the generation of grinding grooves on the surface to be ground of the semiconductor wafer can be suppressed. Therefore, it is not necessary to perform polishing with diamond abrasive grains in the polishing step, and the productivity of the semiconductor wafer is improved.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the grinding groove in the to-be-ground surface of a semiconductor wafer can be suppressed, and the productivity of a semiconductor wafer can be improved.

It is a flowchart which shows the manufacturing method of a semiconductor wafer. 1 is a side view of a semiconductor wafer grinding apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of the semiconductor wafer grinding apparatus shown in FIG. 2. FIG. 3 is a plan view of a grinding wheel of the semiconductor wafer grinding apparatus shown in FIG. 2. FIG. 3 is a bottom view of a wafer support of the semiconductor wafer grinding apparatus shown in FIG. 2. It is explanatory drawing which shows the positional relationship of a grinding wheel and a wafer support. It is a side view of the conventional semiconductor wafer grinding device. It is a schematic diagram of the to-be-ground surface of the semiconductor wafer ground with the conventional semiconductor wafer grinding apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Prior to the description of the present embodiment, a semiconductor wafer manufacturing method will be described with reference to FIG. FIG. 1 is a flowchart showing a method for manufacturing a semiconductor wafer.

  As shown in FIG. 1, first, in step S10, a cylindrical ingot is cut to obtain a disk-shaped semiconductor wafer. Step S10 functions as a cutting process of the present invention. Next, in step S20, the peripheral portion of the semiconductor wafer is chamfered in order to prevent the peripheral portion of the semiconductor wafer from being cracked or chipped. Next, in step S30, the surface to be ground opposite to the main surface of the semiconductor wafer is lapped (ground) so that the semiconductor wafer has a predetermined thickness. Step S30 functions as a lapping process of the present invention. Next, in step S40, the semiconductor wafer is etched to remove processing distortion caused by lapping. In step S50, the surface to be ground of the semiconductor wafer is polished into a mirror surface. Step S50 functions as a polishing process of the present invention. Finally, in step S60, the semiconductor wafer is washed with a chemical solution to remove impurities such as particles. Note that at least one of step S20, step S40, and step S60 may be omitted.

  The semiconductor wafer grinding apparatus of this embodiment is used, for example, in the lapping process of step S30 in FIG. A semiconductor wafer grinding apparatus according to an embodiment of the present invention will be described with reference to FIGS. 2 is a side view of the semiconductor wafer grinding apparatus 1 according to the embodiment of the present invention, FIG. 3 is a perspective view of the semiconductor wafer grinding apparatus 1, and FIG. 4 is a plan view of the grinding wheel 10 of the semiconductor wafer grinding apparatus 1. FIG. 5 is a bottom view of the wafer support 30 of the semiconductor wafer grinding apparatus 1.

  As shown in FIGS. 2 and 3, the semiconductor wafer grinding apparatus 1 includes a grinding wheel 10, a first drive mechanism 20 as a first drive unit, a pair of wafer supports 30, and a second drive unit as a second drive unit. 2 drive mechanism 40.

  The grinding wheel 10 includes a wheel body 11 and a shaft 12. As shown in FIG. 4, the wheel main body 11 is formed in a disk shape, and a through hole 11a into which the shaft 12 is fitted is formed at the center. A plurality of grindstones 13 are provided on the main surface 11 b of the wheel body 11 facing the wafer support 30. The plurality of grindstones 13 are provided so as to extend radially from the center of the wheel main body 11 and slightly protrude in the direction of the central axis 14 (see FIG. 2) of the shaft 12 from the main surface 11b.

  The first drive mechanism 20 is constituted by a motor, a speed reduction mechanism, and the like, and rotationally drives the grinding wheel 10 around the central axis 14.

  The wafer support 30 includes a holder 31 and a support shaft 32. As shown in FIG. 5, the holder 31 is formed in a disc shape and has a main surface 31 a that faces the main surface 11 b of the grinding wheel 10. The support shaft 32 is fixed vertically to the center of the surface of the holder 31 opposite to the main surface 31a. An axis 33 (see FIG. 2) of the support shaft 32 is parallel to the center axis 14 of the grinding wheel 10 and eccentric with respect to the center axis 14.

  A plurality of semiconductor wafers W are detachably supported on the main surface 31a of the holder 31 through fixing means. As the fixing means, for example, wax or an adhesive can be used. The plurality of semiconductor wafers W are fixed to the main surface 31 a with a predetermined angular interval around the axis 33 of the support shaft 32, and the surface to be ground Wa faces the main surface 11 a of the grinding wheel 10. The wafer support 30 can be raised and lowered in the direction of the axis 33 by an elevating mechanism (not shown), a processing position where the semiconductor wafer W abuts on the grindstone 13, and a retreat position where the semiconductor wafer W is separated from the grindstone 13. Can be taken.

  The second drive mechanism 40 includes a motor, a speed reduction mechanism, and the like, and rotationally drives the wafer support 30 around the axis 33.

  Next, a method for grinding the semiconductor wafer W by the semiconductor wafer grinding apparatus 1 will be described with reference to FIG. FIG. 6 is an explanatory view showing the positional relationship between the grinding wheel 10 and the wafer support 30.

  With a pair of wafer supports 30 (see FIG. 3) in the retracted position, a plurality of semiconductor wafers W are attached to the main surfaces 31a (see FIG. 5) of the pair of wafer supports 30 using a jig (not shown). Fix it.

  Next, the pair of wafer supports 30 is lowered by the lifting mechanism and is positioned at the processing position. Then, the grinding wheel 10 is rotationally driven by the first drive mechanism 20, and the pair of wafer supports 30 are rotationally driven in the same direction as the grinding wheel 10 by the second drive mechanism 40.

  By rotating the grinding wheel 10 and the wafer support 30 in the same direction, an unreasonable force is applied to the ground surface Wa as compared with the case where the grinding wheel 10 and the wafer support 30 rotate in the opposite directions. This makes it difficult to finish the ground surface Wa.

  The plurality of grindstones 13 slidably contact the ground surface Wa of the plurality of semiconductor wafers W and grind the ground surface Wa. Each of the plurality of grindstones 13 moves in parallel with the surface to be ground Wa while crossing the surface to be ground Wa of the semiconductor wafer W to grind the surface to be ground Wa. Therefore, the generation of the grinding groove Wb as shown in FIG. 8 on the surface to be ground Wa can be suppressed, and the surface to be ground Wa can be finished beautifully. The reason will be described in detail below.

  The conventional semiconductor wafer polishing apparatus shown in FIG. 7 grinds the surface Wa to be ground by so-called crack propagation type material removal. In this case, particularly when the semiconductor wafer W is formed of a brittle material (silicon, glass, etc.), cracks are likely to remain on the surface Wa to be ground, it is difficult to obtain a beautiful finished surface, and the strength of the semiconductor wafer is also reduced. To do.

  On the other hand, the semiconductor wafer grinding apparatus 1 of the present embodiment grinds the surface Wa to be ground by a processing method that is as close to plastic removal type material removal as possible. That is, since the plurality of radial grindstones 13 slide on the ground surface Wa in a state of crossing the ground surface Wa, the temperature of the ground surface Wa increases due to friction between the grindstone 13 and the ground surface Wa, As the yield stress decreases, the fracture toughness value increases. As a result, crack propagation is suppressed, the depth of cut by the grindstone 13 is reduced, and the damage distribution is shallow and uniform, so that the surface Wa to be ground can be finished beautifully.

  Therefore, in the next polishing process, it is not necessary to perform polishing with diamond abrasive grains for erasing the grinding groove Wb, so that the time of the polishing process is shortened as compared with the case where the grinding groove Wb is generated on the surface to be ground Wa. As a result, the productivity of the semiconductor wafer W is improved.

  While specific embodiments of the present invention have been described above, the present invention is not limited to the embodiments shown in FIGS. 1 to 6 and various modifications can be made to the present embodiments.

  For example, in the present embodiment, the case where the semiconductor wafer grinding apparatus includes a pair of wafer supports has been described, but the number of wafer supports may be one or three or more.

  In this embodiment, the case where four semiconductor wafers are supported on the wafer support has been described. However, the number of semiconductor wafers supported on the wafer support may be three or less, or five or more.

  In this embodiment, the case where the wafer support and the grinding wheel are rotated in the same direction has been described. However, the wafer support and the grinding wheel may be rotated in different directions.

  In addition, various modifications can be made to the present embodiment without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Semiconductor wafer grinding apparatus 10 Grinding wheel 10b Main surface 13 Grinding wheel 20 1st drive mechanism (1st drive means)
30 Wafer support 40 Second drive mechanism (second drive means)
W Semiconductor wafer Wa Surface to be ground

Claims (8)

A semiconductor wafer grinding apparatus for grinding a surface to be ground of a semiconductor wafer,
A grinding wheel,
First driving means for rotationally driving the grinding wheel around a central axis;
A wafer support that supports the semiconductor wafer and is rotatable around an axis parallel to the center axis of the grinding wheel and eccentric to the center axis;
Second driving means for rotationally driving the wafer support,
The grinding wheel includes a plurality of grindstones provided on a main surface facing the wafer support,
The wafer support supports a plurality of the semiconductor wafers and supports the plurality of semiconductor wafers such that the surfaces to be ground of the plurality of semiconductor wafers respectively face the main surface of the grinding wheel. ,
The plurality of grindstones extend radially from the center of the grinding wheel, and the plurality of grindstones are respectively formed so as to cross a region of the main surface facing the surface to be ground of the semiconductor wafer. , Semiconductor wafer grinding equipment.   The semiconductor wafer grinding apparatus according to claim 1, comprising a plurality of the wafer supports. A cutting step of cutting the ingot to obtain a semiconductor wafer;
A lapping step of grinding a surface to be ground of the semiconductor wafer;
Polishing step for polishing the ground surface,
A method for producing a semiconductor wafer, wherein, in the lapping step, the surface to be ground is ground using the semiconductor wafer grinding apparatus according to claim 1 or 2 while rotating the grinding wheel and the wafer support. 4. The method of manufacturing a semiconductor wafer according to claim 3 , wherein in the lapping step, the ground surface is ground while rotating the grinding wheel and the wafer support in the same direction. A semiconductor wafer grinding method comprising:
A semiconductor wafer grinding method, wherein the semiconductor wafer grinding apparatus according to claim 1 or 2 is used to grind the surface to be ground while rotating the grinding wheel and the wafer support. The semiconductor wafer grinding apparatus according to claim 2 , wherein the plurality of wafer supports are arranged at positions symmetrical with respect to a central axis of the grinding wheel. Said second drive means, said wafer support, for rotating in the same direction as the rotational direction of the grinding wheel, according to claim 1, claim 2, and a semiconductor according to any one of claims 6 Wafer grinding equipment. The wafer support includes a holder and a support shaft,
The second driving means rotationally drives the support shaft,
The holder has a main surface facing the main surface of the grinding wheel;
The support shaft is fixed perpendicularly to the center of the surface opposite to the main surface of the holder,
8. The semiconductor wafer grinding apparatus according to claim 1, wherein the main surface of the holder supports a plurality of the semiconductor wafers. 9.

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