JP2017164881A - Cutting blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting blade that can perform cutting to promote self-regenerating blade and excellently cut a surface film of a work-piece in particular.SOLUTION: A cutting blade (10) of the invention comprises an electrocast grindstone part in a circular ring-shape having abrasive-grains (12) fastened with a plating layer (11). In the plating layer are formed penetration holes (14) opened to both sides (11a and 11b) of the layer in a circular ring-shape and extended in a thickness direction and a plurality of non-penetration holes (15) opened to one of both sides and extended in the thickness direction. The cutting blade, even if amounts of cutting blade's wear increase during cutting due to the penetration hole and the non-penetration holes so that the surface film of the work-piece adheres to the blade, can promote a self-regenerating blade and also keep processing quality excellent.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cutting blade for cutting a semiconductor wafer or the like having a surface film.

  As a semiconductor wafer, a semiconductor wafer having a surface film such as an insulating film or a protective film for protecting a device is used. When such a semiconductor wafer is divided into individual devices, there is a case where a dividing method called a so-called step cut is employed using two annular cutting blades formed including abrasive grains. Specifically, in the step cut, first, a half cut for removing the surface film from the semiconductor wafer is performed by one cutting blade for removing the surface film. Thereafter, the other cutting blade for full cut performs full cut to form a cutting groove in a portion where the surface film has been removed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-334751 Japanese Patent Laying-Open No. 2015-018965

  However, when step-cutting a thin semiconductor wafer, the depth of cut into the semiconductor wafer itself becomes shallow in the cutting to remove the surface film, and the ratio of the surface film to the semiconductor wafer in the portion removed by the cutting increases. . For this reason, when a film | membrane adheres to a blade edge | tip, etc., there exists a problem that it becomes difficult to produce what is called a self-growth blade from which an old abrasive grain falls and a new abrasive grain appears, and processing quality deteriorates.

  The present invention has been made in view of such points, and an object of the present invention is to provide a cutting blade which can be cut so as to promote self-generated blades, and in particular, can satisfactorily cut a surface film of a workpiece. To do.

  The cutting blade of the present invention is a cutting blade having an annular electroformed grindstone portion in which abrasive grains are fixed by a plating layer. The plating layer has openings on both side surfaces of the annular shape in the thickness direction. A plurality of through-holes that extend and a plurality of non-through-holes that open in one of both side surfaces and extend in the thickness direction are formed.

  According to this configuration, since the plating layer includes a plurality of holes extending in the thickness direction, it is possible to promote the self-generated blade by increasing the amount of wear during cutting as compared with a blade without holes. As a result, even if the workpiece is a semiconductor wafer having a thin thickness and a surface film, the surface film can be removed satisfactorily and the processing quality can be maintained well.

  According to the present invention, since a plurality of holes extending in the thickness direction are provided, cutting can be performed so as to promote self-generated blades, and in particular, the surface film of the workpiece can be cut well.

It is sectional drawing for description which represented typically an example of the cutting blade which concerns on embodiment. It is the A section of FIG. 1 and the B section expanded sectional view of FIG. It is sectional drawing for description which represented typically another example of the cutting blade which concerns on embodiment. It is an enlarged upper surface photograph for contrast description of the cutting groove of the workpiece after cutting.

  Hereinafter, the cutting blade according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is an explanatory sectional view schematically showing an example of a cutting blade according to an embodiment.

  The cutting blade 10 shown in FIG. 1 is a washer type including only an annular electroformed grinding wheel portion (cutting blade). The cutting blade 10 is sandwiched between two flanges from both sides in the thickness direction and attached to the spindle, and is rotated at a high speed by driving the spindle. Then, the cutting blade 10 rotated at a high speed is cut into the workpiece, and the workpiece is cut along a street of the workpiece to cut the workpiece to form a cutting groove.

  The workpiece may be a semiconductor wafer in which a semiconductor device is formed on a semiconductor substrate such as silicon or gallium arsenide, or an optical device wafer in which an optical device is formed on a ceramic, glass, or sapphire inorganic material substrate. But you can.

  Next, a method for manufacturing the cutting blade 10 will be described. In manufacturing the cutting blade 10, first, a plating bath filled with a nickel plating solution is prepared, and an additive is added to the nickel plating solution. The nickel plating solution is an electrolytic solution containing nickel (ions) such as nickel sulfate, nickel nitrate, nickel chloride, etc., which can be mixed with abrasive grains such as diamond, and its configuration and usage are as described below. It can be set arbitrarily as long as cutting is possible. It is preferable to use an additive that contains a water-soluble ammonium compound that is added to promote the formation of through-holes and non-through-holes, which will be described later, and that has a hydrophobic group such as an alkyl group, an aryl group, or an aralkyl group. . The concentration of the additive with respect to the nickel plating solution is arbitrarily set according to the opening diameters of the through holes and the non-through holes.

  The base covered with the mask having a shape corresponding to the ring-shaped electroformed grinding wheel portion and the nickel electrode are immersed in the nickel plating solution to which the additive is added as described above. Then, a direct current is passed through the nickel plating solution using the base as a cathode and the nickel electrode as an anode, and a plating layer is deposited on the surface of the base not covered with a mask to form an electroformed grindstone. At this time, since the nickel plating solution is agitated at the same time, the abrasive grains are substantially uniformly dispersed in the plating layer containing nickel in the electroforming grindstone, and the abrasive grains are fixed by the plating layer. After depositing and forming the electroformed grindstone portion to a predetermined thickness, the electroformed grindstone portion is peeled off from the base and removed to complete the washer-type cutting blade 10 including only the ring-shaped electroformed grindstone portion.

  FIG. 2 is an enlarged cross-sectional view of a portion A in FIG. As shown in FIG. 2, the cutting blade (electroformed grindstone portion) 10 is a plated layer 11 in a portion given a halftone dot in the figure, and the abrasive grains 12 are fixed to the plated layer 11 by being evenly dispersed. ing. The plated layer 11 has a plurality of through holes 14 and non-through holes 15 extending in the thickness direction of the plated layer 11 (vertical direction in FIG. 2). The through-holes 14 and the non-through-holes 15 are scattered in a region where bubbles are generated and the plating layer 11 is not formed due to the action of the additive when the plating layer 11 is laminated. In the stacking process, the plating layer 11 is grown (elongated) in the thickness direction so that the region is continuous.

  The through holes 14 are opened on both side surfaces 11a and 11b which are the upper and lower surfaces of the plating layer 11 in FIG. As the through hole 14, a hole extending in the thickness direction from one side surface 11 a and a hole extending in the thickness direction from the other side surface 11 b, such as a through hole denoted by reference numeral 14 a, are intermediate portions in the thickness direction. It may be formed so as to communicate with each other. In the drawing, the number of through holes 14a is one, but the same number of through holes 14a are formed. Moreover, it may be formed so as to extend in the thickness direction from either one of the side surfaces 11a and 11b to the other, such as a through hole denoted by reference numeral 14b.

  The non-through hole 15 is opened on one of the side surfaces 11a and 11b, and the opposite side to the opening is located and closed at the middle portion in the thickness direction.

  According to such an embodiment, since the through hole 14 and the non-through hole 15 extending in the thickness direction of the plating layer 11 are provided, the amount of wear of the cutting blade 10 during cutting can be increased. Thus, when forming a cutting groove for removing a surface film on a thin workpiece having a surface film, even if the portion to be removed has more surface film than the workpiece, the film is formed on the cutting edge. It can suppress that the state which adhered has been maintained, and can promote a self-generated blade. Further, the contact area between the plating layer 11 and the abrasive grains 12 is reduced by the through-holes 14 and the non-through-holes 15 so that the abrasive grains 12 can be easily dropped, thereby promoting the self-generated blade. By promoting the self-generated blade in this way, the occurrence of chipping can be prevented, and the machining quality of cutting can be improved.

  Furthermore, even if the cutting blade 10 is chipped during cutting, the size of the chip can be minimized because the through hole 14 and the non-through hole 15 exist. Thereby, generation | occurrence | production of the processing defect by a big chip | tip and a crack producing can be avoided.

  Here, when the average opening diameter d1 of the through-holes 14 and the non-through-holes 15 is formed to be 1/10 to 2 times the average particle diameter d2 of the abrasive grains 12, the self-generated blades in cutting are good. Therefore, the workpiece can be cut well. More preferably, the opening average diameter d1 is set to a size equal to or more than 1/5 and equal to or less than the average particle diameter d2, and the self-generated blade is further promoted and cutting can be performed more satisfactorily. When the opening average diameter d1 is larger than the same size as the average particle diameter d2 and not more than twice, the cutting can be favorably performed by changing the processing conditions so as to reduce the processing load. In addition, it is preferable that the average opening diameter d1 is 1 μm or more and 6 μm or less, and the average particle diameter d2 is preferably formed in the above-described range according to this. The quality can be expected to be equal.

  FIG. 3 is an explanatory sectional view schematically showing another example of the cutting blade according to the embodiment. In addition to the above-described washer type, the cutting blade of the present invention has an annular electroformed grinding wheel portion (cutting blade) 21 and a cone that holds the electroforming grinding wheel portion 21 as in the cutting blade 20 shown in FIG. It is good also as a hub type electrodeposition grindstone (blade) provided with the base-like base 22. The electroformed grinding wheel portion 21 in such a cutting blade 20 is formed in the same manner as the washer-type cutting blade 10 described above. Therefore, when the B portion in the electroformed grinding wheel portion 21 is viewed in an enlarged cross section, the configuration is the same as that shown in FIG.

  The washer-type cutting blade 10 (see FIG. 1) formed the electroformed grinding wheel portion and then peeled the electroformed grinding wheel portion from the base. However, the hub-type cutting blade 20 did not perform such peeling, The base 22 remains fixed to the cast grindstone portion 21. And the outer peripheral area | region of the side in which the electroforming grindstone part 21 is not formed in the base 22 is partially etched, and a part of the electroforming grindstone part 21 covered with the base 22 is exposed.

  As Examples 1 to 13 and a comparative example, a plurality of cutting blades were created and tested. The manufacturing method of each cutting blade has the structure shown in FIG. 1 as described above, and is added so that the average opening diameter of the through holes and the non-through holes is 0.1 to 3.3 μm as shown in Table 1. The agent concentration, current density, and stirring conditions were changed. The abrasive grains in Examples 1 to 13 and Comparative Example were diamond abrasive grains, and the average grain size was 3 μm.

While the cutting blades of Examples 1 to 13 and the comparative example were mounted on a spindle and rotated to cut the workpiece, the cutting blade was processed and fed to form a cutting groove. The processing conditions at that time were as follows. Moreover, before performing cutting, the optimal dress or pre-cut was implemented with respect to each cutting blade.
[Processing conditions]
Workpiece: Wafer with Low-K film with a film thickness (several μm) (φ12 inch thickness 780 μm)
Spindle speed: 40000 rpm
Feeding speed: 50mm / s
Cutting groove depth: 100 μm (half cut) from the surface of the Low-K film
Index: 2mm

  With respect to the workpieces cut with the cutting blades of Examples 1 to 13 and the comparative example, the cutting grooves were observed with an optical microscope and evaluated. Moreover, the state of the cutting blade after cutting was observed. The results are shown in Table 1.

The evaluation of the processing quality in Table 1 is as follows.
○: Reduced chipping ◎: Almost no chipping ×: No change in machining quality compared to cutting blades with no through-holes and non-through-holes. However, it can be improved by changing the processing conditions, and even if a part is chipped, the chipping does not extend due to the influence of the through hole or the non-through hole, and the processing quality is not affected.

  As can be understood from Table 1, a particularly good processing quality with no chipping was obtained when the average diameter of the through holes and non-through holes was 0.7 to 3.0 μm (Examples 3 to 12). Since the average particle diameter of the abrasive grains is 3 μm, the range of the average opening diameter is 1/5 or more and equal to or less than the average grain diameter of the abrasive grains. The reason why the processing quality is good is that the self-generated blade is favorably promoted by the through hole and the non-through hole. In Examples 1 and 2, although the self-sharpening property is lowered and the machining quality is slightly lowered as compared with Examples 3 to 12, machining quality equivalent to that of Examples 3 to 12 can be realized by changing machining conditions and the like. Is. In Example 13, although the processing quality is slightly lowered as compared to Examples 3-12 due to a decrease in the rigidity of the cutting blade in accordance with the increase in the average opening diameter, Examples 3-12 are caused by changes in the processing conditions and the like. Can achieve the same processing quality.

  FIG. 4 is an enlarged photograph for comparison and explanation of the workpiece after cutting. FIG. 4A is an enlarged top view photograph of a cutting groove formed in a workpiece when cutting is performed with the cutting blade of Example 5 under the above-described processing conditions (the spindle rotation speed is changed to 30000 rpm). FIG. 4B is formed on the workpiece when cutting is performed under the above-described processing conditions with a cutting blade having no through-holes and non-through-holes (a normal electroformed blade with a diamond abrasive grain average particle size of 3 μm). It is an enlarged upper surface photograph of the cut groove. In FIG. 4B, chipping is generated by cutting, and the Low-k films on both sides of the cutting groove are peeled off, and the semiconductor wafer device may be damaged. Therefore, there is a problem in the removal of the Low-k film by the cutting blade. In this regard, in FIG. 4A, both side edges of the cutting groove are cleanly linear, and the above problem can be solved by suppressing chipping by cutting. Further, after the same amount of cutting was performed with the cutting blade of Example 5 and the above-described cutting blade having no through hole and no through hole, the amount of wear was measured. The amount of consumption of the blade was about 5 times larger, and it was confirmed that the self-generated blade was performed well.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, direction, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  As described above, the present invention is useful for a cutting blade for cutting a semiconductor wafer having a surface film.

10 Cutting blade (electroforming wheel)
DESCRIPTION OF SYMBOLS 11 Plated layer 11a, 11b Side surface 12 Abrasive grain 14 Through-hole 15 Non-through-hole 20 Cutting blade 21 Electroforming whetstone part

Claims (1)

A cutting blade having an annular electroformed grinding wheel portion in which abrasive grains are fixed by a plating layer,
A cutting blade in which a plurality of through-holes that open on both sides of the ring shape and extend in the thickness direction and non-through holes that open on one of both sides and extend in the thickness direction are formed in the plating layer.

Images