KR20170108868A - Cutting blade - Google Patents

Abstract

The present invention aims to cut the surface of a workpiece to promote autogenous generation and, more specifically, to cut smoothly a surface film of a workpiece. A cutting blade (10) of the present invention is provided with an electroforming grindstone of an annular shape in which a grindstone (12) is fixed in a plating layer (11). In the plating layer, formed are a plurality of through holes (14) opened in the annular side surfaces (11a, 11b) and extending in the thickness direction, and a plurality of non-through holes (15) opened in one side of the both side surfaces and extending in the thickness direction. The cutting blade has a large amount of consumption during cutting due to the through hole and the non-penetration hole, and can promote the autogenous generation even when the surface film of the workpiece is adhered, thus maintaining the machining quality to be good.

Description

CUTTING BLADE

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

As the semiconductor wafer, there is used a surface film such as a protective film for protecting an insulating film or a device. In the case where such a semiconductor wafer is divided into individual devices, there is a case in which a division method in which two cutting blades that are formed into an annular shape and including abrasive grains are used to form so-called step cuts. Specifically, in the step cut, first, a half cut for removing the surface film from the semiconductor wafer is performed by one of the cutting blades for removing the surface film. Thereafter, a full cut is formed in the portion where the surface film is removed by the other cutting blade that facilitates full cutting (see, for example, Patent Document 1).

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

However, in the case of step cutting a thin semiconductor wafer, the depth of cutting into the semiconductor wafer itself becomes shallow at the time of cutting to remove the surface film, and the surface film occupies a large portion of the semiconductor wafer with respect to the portion removed by cutting Loses. For this reason, adhesion of the film to the edge of the blade makes it difficult to produce a so-called self-priming in which the old abrasive is removed and a new abrasive is expressed, which causes a problem that the processing quality is deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cutting blade which can be cut so as to promote native sprouting, and in particular, a surface film of a workpiece can be well cut.

The cutting blade of the present invention is a cutting blade having a toric-shaped electromagnet grindstone in which abrasive grains are fixed in a plating layer. In the plating layer, a through hole extending in both sides of the annular shape and extending in the thickness direction, And a plurality of non-through holes opened in one direction of the through hole and extending in the thickness direction.

According to this configuration, since a plurality of holes extending in the thickness direction are provided in the plating layer, the consumed amount during cutting can be increased and the self-generation can be promoted as compared with the blades without holes. As a result, even if the workpiece is a worn-out semiconductor wafer having a surface film formed thereon, the surface film can be satisfactorily removed, and the quality of the workpiece can be maintained satisfactorily.

According to the present invention, since a plurality of holes extending in the thickness direction are provided, it is possible to cut so as to promote the native sprouting, and in particular, the surface film of the workpiece can be well cut.

1 is a cross-sectional view schematically illustrating an example of a cutting blade according to an embodiment.
Fig. 2 is an enlarged cross-sectional view of part A of Fig. 1 and part B of Fig. 3;
3 is a cross-sectional view schematically illustrating an example other than the cutting blade according to the embodiment.
4 is an enlarged top view photograph for explaining the contrast of the cutting grooves of the workpiece after cutting.

Hereinafter, a cutting blade according to the present embodiment will be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view schematically showing an example of a cutting blade according to an embodiment; Fig.

The cutting blade 10 shown in Fig. 1 is of a washer type comprising only an annular grindstone (blade). The cutting blade 10 is mounted on the spindle by being sandwiched between two flanges from both sides in the thickness direction, and is rotated at a high speed by driving the spindle. Then, the cutting blade 10 is cut into the workpiece and relatively cut along the street of the workpiece, thereby cutting the workpiece to form a cut groove.

Here, the processing member may be a semiconductor wafer on which a semiconductor device is formed on a semiconductor substrate such as silicon or gallium arsenide, or an optical device wafer on which an optical device is formed on a ceramic, glass, or sapphire substrate.

Next, a manufacturing method of the cutting blade 10 will be described. In the production of 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 can be exemplified by an alloy containing nickel (ion) such as nickel sulfate, nickel nitrate, or nickel chloride, and incorporating abrasive grains such as diamond. The constitution and the amount of use can be cut Can be set arbitrarily. The additive is preferably added to promote the formation of through-holes or non-through holes as described later, and contains a water-soluble ammonium compound having 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 diameter of the opening of the through hole or the non-through hole.

The nickel electrode is immersed in the nickel plating solution to which the additive is added as described above, and the base coated with the mask of the shape corresponding to the annular poling grindstone portion and the nickel electrode. Then, a direct current is passed through the nickel plating solution with the anode as the anode and the nickel electrode as the anode, and a plating layer is deposited on the surface of the base not covered with the mask, thereby forming the electromagnet grindstone. At this time, since the stirring of the nickel plating liquid is performed at the same time, the abrasive grains are uniformly dispersed in the plated layer containing nickel in the former abrasive grains, and the abrasive grains are fixed in the plating layer. After the formation of the entire circumference grindstone portion with a predetermined thickness, the grindstone grindstone portion is peeled off from the base and removed to complete the washer-type cutting blade 10 composed of only the annular grindstone portion.

2 is an enlarged cross-sectional view of part A of Fig. 2, the portion where the halftone dots are formed in the drawing is a plating layer 11, and the abrasive grains 12 are generally uniformly dispersed in the plating layer 11 to fix the abrasive grains 12 have. A plurality of through holes 14 and non-through holes 15 extending in the thickness direction of the plating layer 11 (up and down in FIG. 2) are formed in the plating layer 11. The through holes 14 and the non-through holes 15 are formed in such a manner that bubbles are generated by the action of the additive agent when the plating layer 11 is laminated and the regions where the plating layer 11 is not formed are scattered, (Stretches) the plating layer 11 in the thickness direction of the plating layer 11 so as to be continuous in the process of laminating the plating layer 11.

The through holes 14 are opened in both side surfaces 11a and 11b which are upper and lower surfaces of the plating layer 11 in Fig. The through hole 14 is formed with a hole extending in the thickness direction from one side face 11a and a hole extending in the thickness direction from the other side face 11b in the thickness direction middle portion Or may be formed so as to communicate with each other. Although one through hole 14a is provided in the drawing, through holes 14a formed in the same manner are formed in a large proportion. Further, like the through-hole with the reference numeral 14b, 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 side.

The non-through hole 15 is formed in one side of both sides 11a and 11b, and the opposite side to the opening is located in the middle in the thickness direction and closed.

According to this 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 consumption of the cutting blade 10 during cutting can be increased. Thus, in the case of forming the cutting grooves for removing the surface film to the workpiece after the foil having the surface film, even if the portion to be removed has a larger surface film than the workpiece, It is possible to promote the initiation. Also, the contact area between the plating layer 11 and the abrasive grains 12 is reduced by the through holes 14 and the non-penetration holes 15, so that the abrasive grains 12 are easily removed. By thus accelerating the native sprouts, the occurrence of chipping can be prevented, and the cutting quality of cutting can be improved.

In addition, even if the cutting blade 10 is broken during cutting, since the through hole 14 and the non-through hole 15 are present, the size of the defect can be minimized. As a result, it is possible to avoid occurrence of machining failure due to large defects or cracks.

If the average opening diameter d1 of the through hole 14 and the non-through hole 15 is 1/10 to 2 times the average particle diameter d2 of the abrasive grains 12, The native sprouts are favorably promoted, so that the workpiece can be cut satisfactorily. More preferably, the opening average diameter d1 is set to be equal to or less than 1/5 of the average particle diameter d2, and the self-emergence is further promoted and the cutting can be performed better. In the case where the opening average diameter d1 is larger than the equivalent diameter of the average particle diameter d2 and is not more than 2 times, cutting can be performed satisfactorily by changing the processing conditions so as to reduce the processing load. It is preferable to set the average diameter d1 of the opening to 1 mu m or more and 6 mu m or less so as to form the average particle diameter d2 in the above range in accordance therewith. Can be expected to be equal to the machining quality.

3 is a cross-sectional view schematically illustrating an example other than the cutting blade according to the embodiment. The cutting blade of the present invention is not limited to the above-described washer type but may include a toroidal grinding wheel 21 having an annular shape like a cutting blade 20 shown in Fig. 3, (Blade) having the base 22 of the electrodeposited grindstone. The polishing slab 21 of the cutting blade 20 is formed in the same manner as the washer-type cutting blade 10 described above. Therefore, when the B portion of the electromagnet grindstone 21 is enlarged and viewed in cross section, the configuration is the same as that shown in Fig.

In the washer-type cutting blade 10 (see Fig. 1), after forming the entire circumference grindstone portion, the entire circumferential grindstone portion was peeled off from the base. In the hub type cutting blade 20, however, The base 22 is fixed to the base 21. Then, the outer circumferential region of the base 22 on the side where the pole grinding stone 21 is not formed is partially etched to expose a part of the pole grinding stone 21 covered by the base 22.

Example

As examples 1 to 13 and a comparative example, a plurality of cutting blades were manufactured and tested. The manufacturing method of each of the cutting blades has the structure shown in Fig. 1 as described above, and the concentration of the additive, the current density , And stirring conditions were changed. The abrasives of Examples 1 to 13 and Comparative Examples were diamond abrasive grains having an average grain size of 3 탆.

Cutting blades were prepared by cutting and transferring the cutting blades by inserting and rotating the cutting blades of Examples 1 to 13 and the comparative example on the spindle to cut the workpiece. The processing conditions at that time were as follows. Before performing the cutting process, an optimum dress or pre-cut was performed on each cutting blade.

[Processing conditions]

The processed material: a wafer having a low-K film having a film thickness (several 占 퐉) (Φ? 12 inch thickness 780 占 퐉)

Spindle speed: 40000 rpm

Feeding speed: 50 mm / s

Cutting groove depth: 100 mu m (half cut) from the surface of the Low-K film,

Index: 2 mm

The workpieces cut with the cutting blades of Examples 1 to 13 and Comparative Examples were evaluated by observing the cutting grooves with an optical microscope. The state of the cutting blade after cutting was observed. The results are shown in Table 1.

The evaluation of the machining quality in Table 1 is as follows.

○: Chipping reduction

◎: Almost no chipping

X: No change in machining quality as compared to cutting blades in which through holes and non-through holes are not formed

The "deficiency" of the blade state is destroyed at the blade edge of the cutting blade. However, it can be improved by changing the processing conditions. Even if a part is defected, the defects are not elongated due to the influence of the through hole or non- There is no state.

As can be understood from Table 1, particularly good machining quality was obtained in which chipping did not occur in the through-hole and non-through-hole average opening diameter of 0.7 to 3.0 占 퐉 (Examples 3 to 12). Since the average diameter of the abrasive grains is 3 mu m, the range of the average diameter of the abrasive grains is 1/5 or more of the average grain diameter of the abrasive grains. The reason why the processing quality is improved is because the native sprouts are favorably promoted by the through holes and non-through holes. In Examples 1 and 2, the inherent spontaneously pulling-ability was lowered than in Examples 3 to 12, and the processing quality was slightly lowered. However, the processing quality equivalent to that in Examples 3 to 12 could be realized by changing the processing conditions. In Example 13, the machining quality was slightly lowered in comparison with Examples 3 to 12 owing to the decrease in the rigidity of the cutting blades due to the large average diameter of the openings. However, machining conditions were changed, Quality can be achieved.

4 is an enlarged photograph for explaining the contrast of the workpiece after the cutting process. 4A is an enlarged top view of a cutting groove formed in a workpiece in a case where cutting processing is performed under the above processing conditions (the spindle revolution is changed to 30,000 rpm) with the cutting blade of the fifth embodiment. 4B is an enlarged top view of a cutting groove formed in a workpiece in a case where a cutting blade is machined under the above-mentioned machining conditions with a cutting blade (a conventional pole blade having an average diameter of 3 m of diamond abrasive grains) having no through hole and non-through hole. In Fig. 4B, chipping occurs due to cutting, and the Low-k films on both sides of the cutting grooves are peeled off, thereby damaging the device of the semiconductor wafer. Therefore, there is a problem in removing the low-k film by the cutting blade. In this regard, in FIG. 4A, both side edges of the cut grooves are neatly linear, and the occurrence of chipping is suppressed by cutting, thereby solving the above problem. The same amount of cutting was performed with the cutting blades of Example 5 and the above-described through holes and the cutting blades without the non-through holes, and the consumption amounts of the cutting blades were measured. As a result, the consumed amount of the cutting blades of Example 5 And it was confirmed that the self-cultivation was performed well.

Further, the present invention is not limited to the above-described embodiment, and various modifications can be made. In the above-described embodiment, the size, shape, direction, and the like shown in the accompanying drawings are not limited to this, and can be appropriately changed within the range in which the effect of the present invention is exhibited. In addition, the present invention can be appropriately modified without departing from the scope of the present invention.

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

10: Cutting blade (front grinding wheel)
11: Plating layer
11a, 11b: side
12: abrasive grain
14: Through hole
15: Non-penetration
20: cutting blade
21: Jeonju stone section

Claims (1)

1. A cutting blade having an annular grindstone portion of a toric shape in which abrasive grains are fixed in a plating layer,
The plating layer is provided with a through hole extending in the thickness direction and opening on both side surfaces of the annular shape, and a plurality of non-through holes extending in the thickness direction and opening at one side of both sides.

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