JP2015213969A - Dress sheet and processing method using dress sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dress sheet that efficiently dresses a cutting blade while cutting an object to be processed, without causing a problem such as pop of a chip and movement of a wafer, and to provide a processing method using the dress sheet.SOLUTION: In a dress sheet 1 stuck to a face of a wafer W, which is cut with a cutting blade, abrasive grains 23 are contained in a resin layer 2 in order to dress the cutting blade, and the dressing of the cutting blade is carried out in parallel with cutting. Additionally, since a dicing tape can be stuck to the rear face side of the wafer W, even if adhesion of the dress sheet 1 decreases due to the content of the abrasive grains 23, such a problem that pop of a chip or movement of the wafer W causes an abnormal shape of the chip can be prevented. Additionally, adhesion of cut waste to the face is prevented by sticking the dress sheet 1 to the face of the wafer W, which is cut with the cutting blade, and therefore, cutting satisfactory in processing quality can be performed.

Description

  The present invention relates to a dress sheet for dressing a cutting blade and a processing method using the dress sheet.

  A workpiece such as a semiconductor wafer is cut along a predetermined division line by a cutting blade, for example, and divided into individual devices. When cutting the wafer, an adhesive tape is attached to the back side of the wafer.

  When a wafer is cut with a cutting blade, the adhesive of the adhesive tape or the metal film coated on the wafer is entangled with the cutting blade, causing clogging and clogging, resulting in poor sharpness. For this reason, the cutting blade must be dressed appropriately using a dresser board or the like to restore the sharpness, which is cumbersome and reduces the work efficiency. In order to solve such a conventional problem, a processing method has been proposed in which abrasive grains are mixed in an adhesive tape for holding a wafer and cutting is performed using a dicing tape having a blade dressing function. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 08-88202

  However, if the adhesive tape contains abrasive grains at a high concentration (high density) to enhance the dressing function, the adhesive strength of the adhesive tape will be reduced, and chip fly may occur when cutting the wafer. There is a problem that the wafer moves and chips are formed in different shapes. On the other hand, if the concentration of abrasive grains contained in the adhesive tape is low, the dressing function is insufficient.

  The present invention has been considered in view of the above problems, and in a sheet in which a cutting blade can be sharpened while cutting a workpiece, the cutting blade can be effectively used without causing problems such as chip fly and wafer movement. The purpose is to dress.

  A first invention is a thin sheet-like dress sheet that is attached to a workpiece to be cut by a cutting apparatus and conspicuously cut blades, the surface of the workpiece being cut by the cutting blade Abrasive grains that stick to the cutting blade and make the cutting blade stand out are dispersed and contained in a resin layer formed of resin.

  The resin layer is formed of a dress layer in which abrasive grains that conspicuously cut the cutting blade are dispersed and contained in a resin layer that does not have adhesiveness, and a resin that is laminated on the dress layer and whose adhesive strength is reduced by an external stimulus. The adhesive layer may be formed of two layers with an adhesive layer having adhesiveness, and abrasive grains that make up the cutting blade are dispersed and contained in the adhesive layer that is formed of a resin whose adhesive strength is reduced by external stimulation. It may be formed.

  A second invention is a processing method using the above-described dress sheet, the dress sheet laying step for laying the dress sheet on the surface of the workpiece, and the cutting blade after the dress sheet laying step is performed A cutting process for cutting the workpiece together with the dress sheet, and a dress sheet peeling process for peeling the dress sheet from the surface of the workpiece after the cutting after performing the cutting process.

  The dressing sheet of the present invention is formed by dispersing and containing abrasive grains for conspicuous cutting blades in a resin layer formed of a resin, so that the cutting blade can be dressed in parallel with cutting. In addition, by attaching a dressing sheet to the surface of the workpiece to be cut with a cutting blade, it is possible to attach a dicing tape to the back surface of the workpiece. Even if the adhesive strength of the dress sheet is reduced, it is possible to prevent problems such as chip jumping or the movement of the wafer and the formation of chips in an irregular shape. Furthermore, since the dress sheet is adhered to the surface of the workpiece on the side where the cutting blade is cut, the cutting waste does not adhere to the surface, so that the quality of the upper surface can be improved.

  When the resin layer constituting the dress sheet is composed of two layers, a dress layer containing abrasive grains dispersedly and not sticky, and a sticky adhesive layer, the type of cutting blade and the type of workpiece In addition, it is possible to create various types of dress sheets having different abrasive grain sizes and degrees of concentration. Therefore, the adhesive layer can be easily attached to the workpiece, and an optimum dress sheet can be selected and attached to the workpiece according to the type of the cutting blade and the type of the workpiece. . In addition, when the adhesive layer is formed of a resin whose adhesive strength is reduced by external stimulation, the workpiece is processed by applying external stimulus to the adhesive layer before peeling from the workpiece while maintaining strong adhesive strength during cutting. The dress sheet can be easily peeled from the object.

  In the case where the resin layer constituting the dress sheet is formed by dispersing and containing abrasive grains that conspicuously cut the cutting blade in an adhesive layer formed of a resin whose adhesive strength is reduced by an external stimulus, The layer itself can have both the function of sharpening the cutting blade and the function of preventing cutting chips from adhering to the surface on which the cutting blade cuts. Furthermore, by forming the adhesive layer with a resin whose adhesive force is reduced by external stimulation, while maintaining strong adhesive force during cutting, by applying external stimulus to the adhesive layer before peeling from the workpiece, The dress sheet can be easily peeled from the workpiece.

  Further, in the processing method using the dress sheet according to the present invention, after performing the laying step of laying the dress sheet described above on the surface of the workpiece, which is the surface on which the cutting blade cuts, together with the dress sheet by the cutting blade Since the cutting process for cutting the workpiece is performed, it is possible to prevent the cutting waste from adhering to the surface on which the cutting blade cuts and to dress the cutting blade.

It is a perspective view which shows an example of the holding table with which a cutting device is equipped, and a cutting means. It is a perspective view which shows an example of the dress sheet affixed on a wafer and a wafer. It is a 1st example of the sectional view on the AA line of FIG. It is a 2nd example of the sectional view on the AA line of FIG. It is sectional drawing which shows a dress sheet laying process. It is sectional drawing which shows a cutting process. It is sectional drawing which shows a dress sheet peeling process.

  As shown in FIG. 1, a cutting apparatus that cuts a workpiece includes a holding table 10 that holds the workpiece, and a cutting unit 13 that cuts the workpiece held on the holding table 10. And at least. The holding table 10 has a holding surface 11 that holds a workpiece, is movable in the X-axis direction, and the periphery of the holding table 10 is covered with a cover 12. The cutting means 13 includes at least a spindle 14 having an axis in the Y-axis direction, a cutting blade 15 attached to the tip of the spindle 14, and a blade cover 16 that covers the cutting blade 15. When the spindle 14 rotates at a predetermined rotation speed, the cutting blade 15 can be rotated at a predetermined rotation speed.

  A wafer W shown in FIG. 1 is an example of a workpiece to be cut by a cutting apparatus, and devices D are formed on the surface Wa of the wafer W in each region partitioned by a grid-like street S, respectively. . No device is formed on the back surface Wa, which is the surface opposite to the front surface Wa of the wafer W.

  When cutting the wafer W with a cutting apparatus, the dressing sheet 1 in the form of a thin sheet shown in FIG. The cutting blade 15 is used by sticking to the surface to be cut. The surface on the side cut by the cutting blade 15 is the surface Wa of the wafer W in the illustrated example. When cutting by cutting the cutting blade 15 from the back surface Wb of the wafer W, the dress sheet 1 is attached to the back surface Wb.

  The size of the dress sheet 1 may be the same as the size of the wafer W or may be different from the size of the wafer W. In the example of FIG. 3, the dress sheet 1 has the same diameter as the wafer W. For example, the dress sheet 1 has a diameter smaller than that of the wafer W and is large enough to see the end of the street S when the dress sheet 1 is attached to the surface Wa. Then, the street S on the surface Wa of the wafer W can be easily detected from the surface Wa side.

  As shown in FIG. 3, the dress sheet 1 contains abrasive grains that make the cutting blade 15 conspicuous in the resin layer 2 formed of resin. The resin layer 2 constituting the dress sheet 1 is laminated on the lower surface side of the dress layer 20, the dress layer 20 in which the abrasive grains 23 that set the cutting blade 15 are dispersed and contained in a resin layer that does not have adhesiveness, and The adhesive layer 21 is formed of a resin whose adhesive strength is reduced by an external stimulus and is formed of two layers having adhesiveness. The adhesive layer 21 does not contain abrasive grains.

  In the dress layer 20, abrasive grains 23 are dispersed and contained at a high concentration (high density). As the abrasive grains 23, for example, white alundum (WA), green carborundum (GC) or the like is used. By cutting the cutting blade 15 into the dress layer 20, the abrasive grains 23 make the cutting blade 15 conspicuous and the sharpness of the cutting blade 15 can be recovered.

  The pressure-sensitive adhesive layer 21 is formed of, for example, a heat-peeling type resin or a foam-peeling type resin whose adhesive strength is reduced by an external stimulus due to heating. In this case, the adhesive strength of the adhesive layer 21 can be reduced by heating the adhesive layer 21 at a predetermined temperature (for example, 70 ° C. to 80 ° C.). Note that external stimulation by heating may be performed from either the upper or lower surface of the adhesive layer 21.

  Moreover, the adhesive layer 21 may be formed of, for example, an ultraviolet curable resin whose adhesive strength is reduced by an external stimulus caused by ultraviolet rays. Irradiation with ultraviolet rays is performed from the dress layer 20 side. In the case of irradiating ultraviolet rays from the dress layer 20 side, if the concentration of the abrasive grains 23 in the dress layer 20 is too high, the ultraviolet rays may be blocked by the abrasive grains 23 and may not pass through the dress layer 20. In the case of using the ultraviolet curable adhesive layer 21, it is desirable to disperse the abrasive grains 23 in the dress layer 20 with a low concentration.

  The dress sheet 1 is composed of two layers, a dress layer 20 and an adhesive layer 21, so that various types such as an abrasive grain size and a degree of concentration differ depending on the type of the blade portion of the cutting blade 15 and the type of the workpiece. It is possible to create a dress sheet. Accordingly, the adhesive layer 21 can be easily attached to the workpiece, and an optimum dress sheet is selected according to the type of the cutting blade 15 and the type of the workpiece, and is attached to the workpiece. Can be worn.

  A dress sheet 1a shown in FIG. 4 is a second example of a thin sheet dress sheet. The resin layer 2a constituting the dress sheet 1a is composed of only one layer, and is formed of an adhesive layer 24 made of a resin whose adhesive strength is reduced by an external stimulus. The adhesive layer 24 is formed by dispersing and containing abrasive grains 25 that make the cutting blade 15 conspicuous. When the cutting blade 15 shown in FIG. 1 is cut into the adhesive layer 24, the abrasive grains 25 make the cutting blade 15 conspicuous and the sharpness of the cutting blade 15 can be recovered.

  In the dress sheet 1a, the concentration of the abrasive grains 25 is set to be lower than that of the two-layer dress sheet 1 shown in FIG. Desirably, the adhesive layer 24 is dispersed. The adhesive layer 24 can be formed of an ultraviolet curable resin, a heat release type, or a foam release type resin, as with the adhesive layer 21 described above.

  Next, a method for processing the wafer W using a dress sheet when the wafer W is cut by the cutting apparatus will be described. In addition, since the operation | movement at the time of processing the wafer W is the same also when using the dress sheet 1a when using the dress sheet 1a, the operation | movement at the time of using the dress sheet 1 shall be demonstrated below. .

(1) Dressing Sheet Laying Step First, the dressing sheet 1 is laid on the surface Wa of the wafer W as shown in FIG. Specifically, the pressure-sensitive adhesive layer 21 of the dress sheet 1 faces downward and faces the surface Wa of the wafer W and is lowered, and the pressure-sensitive adhesive layer 21 is adhered to the surface Wa of the wafer W, and the dress sheet is applied to the surface Wa of the wafer W. Laying 1

(2) Cutting Step After performing the dress sheet laying step, the wafer W is cut together with the dress sheet 1 with the cutting blade 15, as shown in FIG. First, the dicing tape 3 is attached to the back surface Wb of the wafer W integrated with the dress sheet 1, and the dicing tape 3 side is held by the holding surface 11 of the holding table 10 shown in FIG. Next, the holding table 10 is moved in the X-axis direction, and the wafer W is moved below the cutting means 13. At this time, as shown in FIG. 5, if the dress sheet 1 has the same diameter as the wafer W, the street S is not exposed. The surface Wa is imaged and the street S to be cut by the cutting blade 15 is detected. If the dress sheet 1 is smaller in diameter than the wafer W and the street S is exposed, the street S can be detected using a normal camera that is not an infrared camera.

  Thereafter, while moving the wafer W held on the holding table 10 in the X-axis direction, the cutting means 13 is lowered in the Z-axis direction while the cutting blade 15 is rotated at a predetermined rotational speed. Then, as shown in FIG. 6, the rotating cutting blade 15 is cut from the dress sheet 1 to the dicing tape 3 attached to the back surface Wb of the wafer W.

  Since the cutting blade 15 cuts into the wafer W after being cut into the dress layer 20, the cutting blade 15 is sharpened by the abrasive grains 23 contained in the dress layer 20, and the wafer W is further cut with the cutting blade 15 whose sharpness has been recovered. Can do. Thus, the cutting blade 15 can be dressed in parallel with the cutting, and the cutting quality is improved.

  The cutting performed in this way is performed on all the streets S formed in the vertical and horizontal directions shown in FIG. 1 to form the cutting grooves 4 shown in FIG. Divide into chips.

(3) Dress Sheet Peeling Step After performing the cutting step, the dress sheet 1 is peeled from the surface Wa of the wafer W after cutting, as shown in FIG. When the pressure-sensitive adhesive layer 21 of the dress sheet 1 is formed of a heat-peeling type or foam-peeling resin, the heating means 17 disposed below the wafer W, for example, 70 ° C. to 80 ° C. from the lower side of the wafer W. The adhesive sheet 21 is cured by heating to reduce the adhesive force, and then the dress sheet 1 is peeled from the surface Wa of the wafer W. When the adhesive layer 21 is formed of an ultraviolet curable resin, the dress sheet 1 is peeled from the surface Wa of the wafer W after irradiating ultraviolet rays from the dress layer 20 side to reduce the adhesive force. Thereafter, individual chips having the device D shown in FIG. 1 are picked up from the dicing tape 3 and conveyed to the next step. Since the adhesive layer 21 is formed of a resin whose adhesive force is reduced by an external stimulus, the wafer W is stably supported while maintaining a strong adhesive force in the cutting process, and is attached to the adhesive layer 21 before peeling from the wafer W. By applying an external stimulus, the dress sheet 1 can be easily peeled from the wafer W.

  As described above, the dress sheets 1 and 1a are formed by dispersing the abrasive grains 23 and 25 that set the cutting blade 15 in the resin layers 2 and 2a formed of a resin. Since the wafer W is attached to the surface (the surface Wa of the wafer W) that is cut by the cutting blade 15, the dicing tape 3 can be attached to the back surface Wb of the wafer W. Therefore, even if the dress sheets 1 and 1a contain abrasive grains, even if the adhesive strength of the dress sheets 1 and 1a is reduced, chip jumping occurs or the wafer moves and the chips are formed in an irregular shape. Such a problem does not occur. In addition, since the dress sheet 1 is adhered to the surface Wa of the wafer W, that is, the surface on which the cutting blade 15 is cut, the cutting waste does not adhere to the surface Wa, so that the device quality is improved. Can do.

DESCRIPTION OF SYMBOLS 1, 1a: Dress sheet 2, 2a: Resin layer 3: Dicing tape 4: Cutting groove 20: Dress layer 21: Adhesive layer 23: Abrasive grain 24: Adhesive layer 25: Abrasive grain 10: Holding table 11: Holding surface 12: Cover 13: Cutting means 14: Spindle 15: Cutting blade 16: Blade cover 17: Heating means

Claims (4)

A thin sheet-shaped dress sheet for sticking to a workpiece to be cut in a cutting device and for conspicuous cutting blades,
A dress sheet formed by adhering to a surface of the workpiece to be cut with the cutting blade, and dispersing and containing abrasive grains that make the cutting blade conspicuous in a resin layer.   The resin layer is formed of a dress layer in which abrasive grains that conspicuously cut the cutting blade are dispersed and contained in a resin layer that does not have adhesiveness, and a resin that is laminated on the dress layer and whose adhesive strength is reduced by an external stimulus. The dress sheet according to claim 1, wherein the dress sheet is formed of two layers including an adhesive layer having adhesiveness.   The dress sheet according to claim 1, wherein the resin layer is formed of a resin whose adhesive strength is reduced by an external stimulus and is formed by dispersing and containing abrasive grains that make the cutting blade stand out. A processing method using the dress sheet according to any one of claims 1 to 3,
A dress sheet laying step of laying the dress sheet on the surface of the workpiece;
After performing the dress sheet laying step, a cutting step of cutting a workpiece together with the dress sheet by the cutting blade;
A dressing sheet peeling step of peeling the dress sheet from the surface of the workpiece after the cutting after performing the cutting step.

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