JP6315471B2 - Method of dividing plate workpiece - Google Patents

Description

  The present invention relates to a plate-like workpiece dividing method for dividing a plate-like workpiece such as a semiconductor wafer into individual chips.

  In order to divide a wafer such as a semiconductor wafer, a cutting apparatus in which a cutting blade is attached to the tip of a spindle is mainly used. The wafer is divided into a plurality of chips by cutting with the cutting blade, and the side surface of each chip is polished by the abrasive grains of the used cutting blade.

  However, due to the size of the abrasive grains or the biting between the cutting blade and the tip of the generated cutting waste, a crack like a crack is suddenly generated on the cut surface which should be originally polished. Sometimes. Such a flaw causes a reduction in the bending strength of the chip and may lead to breakage of the semiconductor chip.

  Japanese Patent Laid-Open No. 2-303050 discloses a method of forming a split groove with a thin cutting blade, then slightly cutting the cut surface of the split groove with a cutting blade having a small abrasive grain size and thicker than the split groove, and polishing the cut surface. It is disclosed in the publication.

  However, since a grindstone with a small abrasive grain size is easily worn, the blade thickness of the cutting blade gradually decreases, and as a result, the cut surface cannot be polished. On the other hand, a method of polishing a side surface of a chip with a thin cutting blade is disclosed in Japanese Patent Laid-Open No. 2003-300135.

JP-A-2-303050 JP 2003-300135 A

  However, in the method of polishing the chip side surface with the thin cutting blade disclosed in Patent Document 2, the thin cutting blade easily escapes (bends) into the dividing groove, and the cutting blade does not cut into the cut surface, so that the polishing cannot be performed. Was left.

  This invention is made | formed in view of such a point, The place made into the objective is providing the division | segmentation method of the plate-shaped workpiece which can grind | polish the cut surface of a division | segmentation groove | channel effectively.

  According to the present invention, there is provided a plate-like workpiece dividing method for dividing a plate-like workpiece, wherein a dividing groove is formed by a first cutting blade in a plate-like workpiece held by a chuck table, A dividing step for dividing a plate-like workpiece into a plurality of chips, and a second cutting blade having a smaller blade thickness than that of the first cutting blade and containing a smaller abrasive grain size after the dividing step is performed. A polishing step of grinding a cut surface of the plate-like workpiece along the divided grooves and polishing a side surface of the chip, wherein the cutting of the second cutting blade is performed in the polishing step. A fluid is supplied to a surface opposite to the surface in contact with the surface, and the second cutting blade is pressed against the cutting surface of the plate-like workpiece by the pressure of the fluid. A method of dividing objects is provided.

  Preferably, the second cutting blade is composed of a pair of polishing cutting blades arranged in parallel at a predetermined distance, and in the polishing step, the pair of polishing cutting blades are cut surfaces on both sides of the dividing groove. Are simultaneously ground and polished, and the fluid is supplied between the pair of polishing cutting blades.

  According to the plate-like workpiece dividing method of the present invention, when a thin cutting blade is used to slightly cut one cut surface of the dividing groove and polish the cut surface, fluid is supplied to the opposite surface of the cutting blade. By doing so, it is possible to prevent the cutting blade from being pressed toward the cut surface and escaping.

  In addition, when polishing the cut surfaces on both sides of the split groove with two thin cutting blades, by supplying fluid from between the two cutting blades, the cut surfaces on both sides of the split groove can be effectively removed at once. Can be polished.

It is a surface side perspective view of a semiconductor wafer. It is a perspective view of the frame unit with which the semiconductor wafer was supported by the annular frame via the dicing tape. It is sectional drawing which shows a division | segmentation step. It is sectional drawing which shows the grinding | polishing step of 1st Embodiment. FIG. 5A is a sectional view showing a polishing step of the second embodiment, and FIG. 5B is a plan view thereof.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a front side perspective view of a semiconductor wafer (hereinafter simply referred to as a wafer) 11 which is a kind of plate-like workpiece.

  A plurality of planned division lines (streets) 13 are formed in a lattice pattern on the surface 11 a of the wafer 11, and devices 15 such as ICs and LSIs are formed in each region partitioned by the planned division lines 13. 11 b is the back surface of the wafer 11.

  In the dividing method of this embodiment, the wafer 11 is put into the cutting apparatus in the form of the frame unit 17 shown in FIG. The frame unit 17 includes an annular frame F, a dicing tape T having an outer peripheral portion attached to the annular frame, and a wafer 11 having a back surface attached to the dicing tape T.

  Referring to FIG. 3, a cross-sectional view of the dividing step is shown. Before performing the division step, the surface 11a of the wafer 11 is imaged by the imaging unit of the cutting apparatus, and the division line 13 to be cut and the first cutting blade 22 are aligned in the machining feed direction (X-axis direction). Perform alignment.

  After this alignment is performed on the planned division line 13 that extends in the first direction, the chuck table 10 is rotated by 90 °, and then the planned division line 13 that extends in the second direction orthogonal to the first direction. carry out.

  After the alignment, the dividing step of dividing the wafer 11 into a plurality of chips by forming a dividing groove along the scheduled dividing line 13 extending in the first direction of the wafer 11 by the first cutting blade 22 of the cutting unit 18. carry out.

  The cutting unit 18 includes a spindle 20 that is rotationally driven by a motor (not shown), and a first cutting blade 22 that is attached to the tip of the spindle 20. The chuck table 10 includes a metal frame 12 formed of SUS (stainless steel) or the like, and a suction holding unit 14 formed of a porous material such as porous ceramics surrounded by the frame 12. .

  In the dividing step, the back surface side of the wafer 11 is sucked and held through the dicing tape T by the suction holding portion 14 of the chuck table 10 to expose the front surface 11a. Then, the annular frame F is clamped and fixed by a clamp 16 attached to the chuck table 10.

  In the dividing step, the first cutting blade 22 that rotates at a high speed is cut to the dicing tape T along the division line 13 that extends in the first direction, and the chuck table 10 is processed and fed in the X-axis direction, A division groove 19 is formed along the division line 13.

  While the cutting unit 18 is indexed and fed in the Y-axis direction by the pitch of the division line 13, the same division groove is formed by the first cutting blade 22 along all the division lines 13 extending in the first direction. .

  Next, after the chuck table 10 is rotated by 90 °, a similar dividing groove 19 is formed along the planned dividing line 13 extending in the second direction orthogonal to the first direction, and the wafer 11 is divided into individual chips. To divide. Reference numeral 19a denotes a cut surface.

  In the dividing method of the present invention, after the dividing step is performed, the second cutting blade having a smaller blade thickness than the first cutting blade 22 and containing a smaller abrasive particle diameter is formed along the dividing groove 19 on the wafer 11. The cutting step is performed by grinding (cutting) the cut surface and polishing the side surfaces of the individually divided chips.

  As shown in FIG. 4, the cutting unit 18 </ b> A used in this polishing step has a second blade having a smaller blade thickness than the first cutting blade 22 at the tip of the spindle 20 that rotates at a high speed and a smaller abrasive particle size. A cutting blade 22A is mounted.

  In the polishing step, the second cutting blade 22A that rotates at high speed is pressed against the one cut surface 19a along the divided groove 19 to grind (cut) the cut surface 19a, and the side surfaces of the individually divided chips are polished.

  At this time, the fluid 25 is ejected from the nozzle 24 toward the surface opposite to the surface that contacts the cutting surface 19a of the second cutting blade 22A, and the second cutting blade 22A is moved to the wafer 11 by the pressure of the ejected fluid. To the cut surface 19a. Thereby, it is possible to prevent the second cutting blade 22A from escaping from the cut surface 19a, and the cut surface 19a can be effectively polished. The fluid to be ejected is preferably pressurized.

  While cutting and feeding the cutting unit 18A by the pitch of the division line 13 extending in the first direction, one cut surface 19a of the division groove 19 formed along the division line 13 extending in the first direction is formed. The second cutting blade 22A is similarly ground (cut), and the side surfaces of the individually divided chips are polished.

  Next, after the chuck table 10 is rotated by 180 °, the other cut surface 19a of the dividing groove 19 formed along the planned dividing line 13 extending in the first direction is similarly ground by the second cutting blade 22A. (Cutting) and polishing the side surfaces of the individually divided chips.

  As described above, this polishing step is performed while ejecting fluid from the nozzle 24 toward the surface opposite to the surface in contact with the cutting surface of the second cutting blade 22A. The fluid is preferably pure water.

  When the polishing step of the cut surfaces on both sides of all the dividing grooves 19 extending in the first direction is completed, the chuck table 10 is rotated by 90 ° and then formed along the planned dividing line 13 extending in the second direction. Polishing of one cut surface 19a of the divided groove 19 is similarly performed. Next, after the chuck table 10 is rotated 180 °, the cut surface 19a on the opposite side of the dividing groove 19 extending in the second direction is similarly polished.

  Next, with reference to FIG. 5, the grinding | polishing step of 2nd Embodiment of this invention is demonstrated. In the polishing step of the second embodiment, as shown in FIG. 5A, a cutting unit 18 </ b> B in which a pair of polishing cutting blades 22 </ b> A are mounted in parallel to the tip portion of the spindle 20 with a predetermined distance apart by a spacer 26. Is used.

  The polishing cutting blade 22A has the same structure as the second cutting blade 22A. That is, the polishing cutting blade 22 </ b> A is thinner than the first cutting blade 22 and contains abrasive grains having a diameter smaller than that of the abrasive grains contained in the first cutting blade 22. The nozzle 24 that ejects the fluid 25 is disposed between the pair of polishing cutting blades 22A.

  The thickness including the spacer 26 of the pair of polishing cutting blades 22 </ b> A attached to the tip end of the spindle 20 via the spacer 26 is set to be slightly thicker than the width of the dividing groove 19.

  Thus, in the polishing step of the second embodiment, the pair of polishing cutting blades 22A can simultaneously grind (cut) the cut surfaces 19a on both sides of the dividing groove 19 to polish the side surfaces of the individual chips.

  During the polishing step, polishing is performed while jetting the fluid 25 from the nozzle 24 between the pair of polishing cutting blades 22 </ b> A, whereby the polishing cutting blade 22 </ b> A can be prevented from escaping into the divided grooves 19. The cut surfaces 19a on both sides of the dividing groove 19 can be polished at a time.

  In FIG. 5B, the arrow X1 indicates the blade traveling direction, and the nozzle 24 is disposed on the front side of the pair of polishing cutting blades 22A, and between the nozzle 24 and the pair of polishing cutting blades 22A. The cutting surface 19a is polished while the fluid 25 is ejected. Reference numeral 19a 'denotes a polished cut surface.

  According to the polishing step of the present embodiment, the cut surfaces 19a on both sides of the dividing groove 19 can be polished at one time. Therefore, compared with the polishing step of the first embodiment described with reference to FIG. Such time can be greatly reduced.

  In the above-described embodiment, the example in which the semiconductor wafer 11 is employed as the plate-like workpiece has been described. However, the plate-like workpiece is not limited to the semiconductor wafer, and other wafers such as optical device wafers, ceramics, etc. The present invention can be similarly applied to other plate-like workpieces such as substrates and resin substrates.

11 Semiconductor wafer 13 Scheduled division line 15 Device 17 Frame unit 18, 18A, 18B Cutting unit 20 Spindle 22 First cutting blade 22A Second cutting blade (polishing cutting blade)
24 Nozzle 25 Fluid 26 Spacer

Claims (2)

A plate-like workpiece dividing method for dividing a plate-like workpiece,
A dividing step of forming a dividing groove with a first cutting blade in a plate-like workpiece held by the chuck table, and dividing the plate-like workpiece into a plurality of chips;
After performing the dividing step, the plate-like workpiece is cut along the dividing groove with a second cutting blade having a smaller blade thickness than the first cutting blade and containing a smaller abrasive particle diameter. A polishing step of grinding a surface and polishing a side surface of the chip,
In the polishing step,
A fluid is supplied to a surface of the second cutting blade opposite to the surface in contact with the cutting surface, and the second cutting blade is moved to the cutting surface of the plate-like workpiece by the pressure of the fluid. A method for dividing a plate-like workpiece characterized by pressing. The second cutting blade is composed of a pair of polishing cutting blades arranged in parallel at a predetermined distance,
In the polishing step, the pair of polishing cutting blades simultaneously grind and polish the cut surfaces on both sides of the dividing groove,
2. The plate-like workpiece dividing method according to claim 1, wherein the fluid is supplied between the pair of polishing cutting blades.