JP7037422B2 - Processing method of work piece - Google Patents

Description

The present invention relates to a method for processing a workpiece having an adhesive layer formed on the back surface.

For example, a wafer (workpiece) having an adhesive layer in which an adhesive layer for die bonding called a die attach film (DAF) is formed on the back surface of a semiconductor wafer is known. When cutting this type of work piece, the adhesive layer side of the work piece is generally attached to a tape consisting of a base material and a glue layer formed on the base material, and the cutting blade reaches a depth up to the tape. Is cut and the workpiece is cut to form a semiconductor device with an adhesive layer (see, for example, Patent Document 1). On the other hand, power semiconductor devices and in-vehicle semiconductor devices are mounted on a substrate by soldering. In recent years, as the use of lead has begun to be regulated, for example, a die attach film as a conductive adhesive layer mixed with metal particles such as silver has also begun to be used (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2016-0630660 Japanese Unexamined Patent Publication No. 2017-002181

However, the above-mentioned adhesive layer is formed of a ductile resin material (ductile material) such as a polyimide resin, an epoxy resin, and an acrylic resin fat. Therefore, when the adhesive layer having ductility is cut with a cutting blade, the adhesive layer is stretched as the cutting blade rotates, and cracks may occur at the interface with the wafer. Cracks can also cause problems such as the adhesive layer peeling off or the cracks extending and damaging the device. In particular, when the adhesive layer is a conductive adhesive layer in which metal particles (ductile material) having the same ductility are mixed in the ductile resin material, it is expected that the above-mentioned problems will occur remarkably. ..

The present invention has been made in view of the above, and an object of the present invention is to provide a method for processing a workpiece that can reduce the risk of damaging a device or a device chip.

In order to solve the above-mentioned problems and achieve the object, the present invention has a waiha having a plurality of intersecting streets and a device formed in each region of the surface partitioned by the streets, and the waiha. A method for processing an workpiece including an adhesive layer formed on the back surface, wherein a tape is attached to the front surface side of the workpiece to expose the adhesive layer, and a tape attachment step. After performing the tape application step, the adhesive layer removing step of removing the adhesive layer on the outer periphery of the workpiece to form an exposed portion where the back surface of the wafer is exposed, and the adhesive layer removing. After performing the steps, a street detection step of detecting a street through the exposed portion using an infrared camera transmitted through the waha, and a work piece along the detected street after performing the street detection step. It is equipped with a cutting step for cutting the workpiece from the back surface of the work piece with a cutting blade.

According to this configuration, the work piece is cut from the adhesive layer with the adhesive layer on the back side of the work piece facing up, so that the adhesive layer is supported by the wafer. The adhesive layer is less likely to be stretched as the cutting blade rotates, and the occurrence of cracks in the wafer can be suppressed. Therefore, the risk of damage to the device or device chip can be reduced. Further, in order to include an adhesive layer removing step of removing the adhesive layer on the outer periphery of the workpiece to form an exposed portion in which the back surface of the wafer is exposed, the street detection step is exposed using an infrared camera. The street can be easily detected by passing through the portion.

Further, the present invention is formed on a wafer having a plurality of streets intersecting the surface and a device region in which a device is formed in each region partitioned by the streets, and at least on the back surface of the wafer corresponding to the device region. A method of processing an workpiece comprising an adhesive layer having a size smaller than the size of a wafer, wherein a tape is attached to the surface side of the workpiece to expose the adhesive layer. Street detection that detects a street through a region where the back surface of the wafer is exposed on the outer periphery of the adhesive layer using an infrared camera that transmits the tape attachment step and the tape attachment step. It includes a step and a cutting step of cutting the workpiece from the back surface of the workpiece along the detected street with a cutting blade after performing the street detection step.

According to this configuration, the work piece is cut from the adhesive layer with the adhesive layer on the back side of the work piece facing up, so that the adhesive layer is supported by the wafer. The adhesive layer is less likely to be stretched as the cutting blade rotates, and the occurrence of cracks in the wafer can be suppressed. Therefore, the risk of damage to the device or device chip can be reduced. Further, since the workpiece includes an adhesive layer formed on the back surface of the wafer corresponding to at least the device region and having a size smaller than that of the wafer, an adhesive layer removing step for removing the adhesive layer on the outer periphery of the workpiece. In the street detection step, the street can be easily detected by transmitting through the outer peripheral portion of the wafer using an infrared camera.

In the above configuration, the cutting step is a first cutting step in which the adhesive layer is divided by cutting to a depth reaching the waha with the first cutting blade, and an uncut portion is formed on the surface side of the waha. After performing the first cutting step, a second cutting blade having a thickness thinner than that of the first cutting blade is cut to a depth reaching the tape, and the uncut portion is cut along the street. It may be provided with a second cutting step for cutting.

Further, the second cutting blade used in the second cutting step may contain abrasive grains finer than the abrasive grains contained in the first cutting blade. Further, the adhesive layer may be composed of metal particles and a resin.

According to the present invention, since the work piece is cut from the work piece with a cutting blade with the adhesive layer on the back side of the work piece facing up, this adhesive layer is supported by a wafer. The adhesive layer is less likely to be stretched as the cutting blade rotates, and the occurrence of cracks in the wafer can be suppressed. Therefore, the risk of damage to the device or device chip can be reduced.

FIG. 1 is a perspective view of the surface side of a wafer with a die attach film, which is an example of a work piece to be processed. FIG. 2 is a perspective view of the back surface side of the wafer with a die attach film shown in FIG. FIG. 3 is a flowchart showing a procedure of a processing method for a workpiece according to the present embodiment. FIG. 4 is a perspective view showing an outline of the tape application step. FIG. 5 is a perspective view showing an example of a cutting device that processes a workpiece. FIG. 6 is a side view showing an outline of the adhesive layer removing step. FIG. 7 is a side view showing an outline of the street detection step. FIG. 8 is a side view showing an outline of the first cutting step. FIG. 9 is a partial cross-sectional view of a wafer with a DAF showing a first cutting groove formed in the first cutting step. FIG. 10 is a side view showing an outline of the second cutting step. FIG. 11 is a partial cross-sectional view of a wafer with a DAF showing a second cutting groove formed so as to overlap the first cutting groove in the second cutting step. FIG. 12 is a perspective view of the surface side of a wafer with a die attach film, which is a modified example of the workpiece to be processed.

An embodiment (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions or changes of the configuration can be made without departing from the gist of the present invention.

The processing method of the workpiece according to the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of the surface side of a wafer with a die attach film, which is an example of a work piece to be processed. FIG. 2 is a perspective view of the back surface side of the wafer with a die attach film shown in FIG.

The method for processing a workpiece according to the present embodiment is to cut a wafer with a die attach film (hereinafter referred to as a wafer with a DAF) 200 as a workpiece and divide it into individual device chips. The wafer 200 with DAF is configured to include a wafer 201 and a die attach film (hereinafter referred to as DAF) 202 as an adhesive layer laminated on the wafer 201. The wafer 201 is a plate such as a disk-shaped semiconductor wafer or optical device wafer using silicon, gallium arsenide (GaAs) as a base material, a glass or sapphire (Al2 O ₃ ) -based plate _- shaped inorganic material substrate, or the like. It is a variety of processing materials. As shown in FIG. 1, on the surface of the wafer 201, in a plurality of areas partitioned by a plurality of intersecting planned division lines (streets) 204, for example, an IC (Integrated Circuit), an LSI (Large Scale Integration), or the like is formed. The device 205 is formed.

The DAF202 contains metal particles (conductive particles) mixed in a ductile resin material such as a polyimide resin, an epoxy resin, and an acrylic resin fat, and is formed on the back surface 206 side of the weight 201. In the present embodiment, the DAF 202 is formed in the shape of a disk having the same size as the wafer 201. The metal particles are, for example, silver fillers (silver particles), and the content in the resin material described above is set to 70 to 90 [% by weight]. Further, the average particle size of the metal particles is preferably 1 to 10 [μm]. The DAF202 may be formed by forming a film-like (sheet-like) resin material mixed with metal particles, and the DAF202 may be attached to the back surface 206 of the wafer 201, or the resin material mixed with metal particles may be attached. May be formed by coating the back surface 206 of the wafer 201 to form the DAF 202.

FIG. 3 is a flowchart showing a procedure of a processing method for a workpiece according to the present embodiment. FIG. 4 is a perspective view showing an outline of the tape application step. First, the dicing tape (tape) 207 is attached to the surface 203 side of the wafer 200 with DAF as the workpiece (tape attachment step S1). Specifically, as shown in FIG. 4, the frame unit 209 is formed. The frame unit 209 supports the wafer 200 with DAF, the dicing tape 207 attached to the surface 203 (see FIG. 1) side of the wafer 200 with DAF, and the wafer 200 with DAF via the dicing tape 207. It is provided with an annular frame 208. That is, the wafer 200 with DAF is supported by the annular frame 208 via the dicing tape 207, and the DAF 202 of the wafer 200 with DAF is exposed.

FIG. 5 is a perspective view showing an example of a cutting device that processes a workpiece. In the present embodiment, the cutting device 100 executes the adhesive layer removing step S2, the street detection step S3, and the cutting step S4 on the wafer 200 with DAF of the frame unit 209. As shown in FIG. 5, the cutting device 100 includes a chuck table 1, a cutting means 2 having a cutting blade 21, an X-axis moving means 3, a portal frame 4, a Y-axis moving means 5, and a Z-axis moving. The means 6, the cassette elevator 7, and the cleaning means 8 are provided.

The chuck table 1 is formed in a disk shape, and includes a holding surface 11 and a plurality of frame chucks 12. The chuck table 1 can move relative to the apparatus main body 101 in the cutting feed direction (X-axis direction). Further, the chuck table 1 is configured to be rotatable around the central axis of the holding surface 11, and can be adjusted to an arbitrary rotation angle with respect to the cutting means 2. The holding surface 11 holds the wafer 200 with DAF. The holding surface 11 is the upper end surface of the chuck table 1 in the vertical direction, and is formed flat with respect to the horizontal plane. The holding surface 11 is made of, for example, porous ceramic or the like, and the wafer 200 with DAF of the frame unit 209 is sucked and held via the dicing tape 207 by the negative pressure of a vacuum suction source (not shown). The plurality of frame chucks 12 are arranged at four locations around the holding surface 11 and sandwich and fix the annular frame 208 of the frame unit 209.

The cutting means 2 processes a wafer 200 with a DAF held on the chuck table 1 with a cutting blade 21. The cutting means 2 is fixed so as to be movable in the indexing direction (Y-axis direction) and the cutting feed direction (Z-axis direction) via the Y-axis moving means 5 and the Z-axis moving means 6 arranged on the portal frame 4. ing. In addition to the cutting blade 21, the cutting means 2 includes a spindle 22, a housing 23, a nozzle 24, a first imaging means 25, and a second imaging means (infrared camera) 26.

The cutting blade 21 is an ultrathin disk-shaped and annularly formed cutting wheel having a cutting edge obtained by solidifying diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains with a bond material such as metal or resin. .. The spindle 22 is detachably mounted with cutting blades 21 having different blade thicknesses. The housing 23 has a drive source such as a motor, and supports the spindle 22 rotatably around a rotation axis in the indexing feed direction. The nozzle 24 supplies cutting water to the cutting blade 21 and the wafer 200 with DAF. The first image pickup means 25 is a camera having an image pickup element such as a CCD (Charge Coupled Device) image sensor. The second image pickup means 26 is, for example, an infrared camera having an infrared irradiation unit (not shown) that irradiates infrared rays, an image pickup element (infrared CCD) that outputs an electric signal corresponding to infrared rays, and the like. The scheduled division line 204 can be detected based on the image acquired by the first image pickup means 25 or the second image pickup means 26.

The X-axis moving means 3 processes and feeds the chuck table 1 and the cutting means 2 relative to each other in the cutting feed direction. The X-axis moving means 3 includes, for example, a pulse motor, a ball screw, a guide rail, and the like. The X-axis moving means 3 moves the moving base 31 to which the chuck table 1 is fixed relative to the apparatus main body 101 in the cutting feed direction.

The portal frame 4 supports the cutting means 2 so as to be movable in each of the indexing feed direction and the cutting feed direction. The portal frame 4 is erected on the apparatus main body 101 across the X-axis moving means 3 in the indexing feed direction.

The Y-axis moving means 5 is arranged on the portal frame 4, and the chuck table 1 and the cutting means 2 are relatively moved in the indexing feed direction. The Y-axis moving means 5 includes, for example, a pulse motor, a ball screw, a guide rail, and the like, and moves the cutting means 2 relative to the chuck table 1 in the indexing feed direction.

The Z-axis moving means 6 is arranged on the portal frame 4, and the chuck table 1 and the cutting means 2 are relatively moved in the cutting feed direction. The Z-axis moving means 6 includes, for example, a pulse motor, a ball screw, a guide rail, and the like. The Z-axis moving means 6 moves the moving base 61 to which the cutting means 2 is fixed relative to the chuck table 1 in the cutting feed direction.

The cassette elevator 7 supports the apparatus main body 101 so as to be able to move up and down the cassette 71 containing a plurality of frame units 209 in the vertical direction. The cleaning means 8 holds the frame unit 209 cut by the cutting means 2 on the spinner table 81 and cleans it.

Returning to the flowchart of FIG. 3, the continuation of the procedure of the processing method of the workpiece will be described. FIG. 6 is a side view showing an outline of the adhesive layer removing step. FIG. 7 is a side view showing an outline of the street detection step. FIG. 8 is a side view showing an outline of the first cutting step. FIG. 9 is a partial cross-sectional view of a wafer with a DAF showing a first cutting groove formed in the first cutting step. FIG. 10 is a side view showing an outline of the second cutting step. FIG. 11 is a partial cross-sectional view of a wafer with a DAF showing a second cutting groove formed so as to overlap the first cutting groove in the second cutting step.

After performing the tape attaching step S1 described above, the outer peripheral portion of the DAF 202 in the wafer 200 with DAF is removed (adhesive layer removing step S2). Specifically, as shown in FIG. 6, the wafer 200 with DAF is held by the chuck table 1 of the cutting device 100 via the dicing tape 207, and the annular frame 208 is fixed by the frame chuck 12. In this state, while rotating the chuck table 1 around the axis parallel to the Z-axis direction (arrow R1 direction), the grinding blade 21A is cut into the DAF202 on the outer peripheral edge of the wafer 200 with DAF to cut the outer peripheral edge. Remove DAF202. As a result, the exposed portion 201A with the back surface side of the wafer 201 exposed is formed. The grinding blade 21A is formed to be thicker than the cutting blade used in the cutting step S4 described later, and an exposed portion 201A having a predetermined width (for example, 3 mm) is formed on the outer peripheral edge of the wafer 200 with DAF. To. The exposed portion 201A may have a width sufficient to detect the scheduled division line 204 in the street detection step S3 described later, and may be appropriately changed depending on the arrangement relationship between the scheduled division line 204 and the device 205 on the wafer 201. Can be done. Further, the exposed portion 201A may be formed by cutting while rotating a plurality of times instead of forming by rotating the chuck table 1 once. For example, using a grinding blade 21A having a width of 1 mm, the chuck table 1 is rotated once to cut in an annular shape, and then the grinding blade 21A is moved in the radial direction of the wafer 200 with DAF. Then, by repeating the operation of rotating the chuck table 1 again and cutting in an annular shape, the exposed portion 201A having a predetermined width (for example, 3 mm) can be formed.

Next, the scheduled division line 204 is detected via the exposed portion 201A (street detection step S3). Specifically, as shown in FIG. 7, the second imaging means 26 is used to detect the scheduled division line 204 on the surface 203 side through the exposed portion 201A exposed on the outer peripheral edge. The second imaging means 26 is an infrared camera as described above, and images the scheduled division line 204 formed on the front surface 203 of the wafer 201 from the back surface side of the wafer 201. In general, an infrared camera can obtain a clearer image as the thickness of the object to be imaged becomes thinner. In the configuration in which the DAF is provided on the back surface 206 of the wafer 201, even if the DAF is a non-conductive DAF that does not contain metal particles, the thickness to be transmitted by the infrared camera increases by the amount of the DAF, so that the wafer is thickened. It becomes difficult to detect the scheduled division line 204 formed on the surface 203 of 201. Further, in the configuration in which the metal particles are mixed in the resin material to provide the DAF202 having conductivity as in the present embodiment, the infrared rays do not pass through the DAF202, particularly the metal particles in the DAF202. Therefore, it becomes more difficult to detect the planned division line 204 with the infrared camera through the DAF202. In the present embodiment, the DAF 202 on the outer peripheral edge of the wafer 200 with DAF is removed to form the exposed portion 201A on which the wafer 201 is exposed, so that infrared rays pass through the exposed portion 201A which is a part of the wafer 201 and are therefore divided. Scheduled line 204 can be easily detected. Alignment for aligning the wafer 200 with DAF and the cutting blade 21 of the cutting means 2 is performed by the position of the detected division scheduled line 204.

Next, the wafer 200 with DAF is cut from the DAF202 side along the detected division schedule line 204 (cutting step S4). In the present embodiment, the cutting step S4 is carried out in two stages, the first cutting step S4A and the second cutting step S4B. In the first cutting step S4A, as shown in FIG. 8, the chuck table 1 is fed in the cutting feed direction (X1 direction in the figure) while rotating the first cutting blade 21B in a predetermined direction (arrow R1 direction in the figure). .. As a result, the first cutting blade 21B cuts the wafer 200 with DAF along the scheduled division line 204 (FIG. 9) in a so-called down cut in which machining proceeds while cutting downward with respect to the wafer 200 with DAF.

The first cutting blade 21B is, for example, a blade in which abrasive grains having a mesh size of # 1700 to # 3000 are fixed to a base by electroforming. In this first cutting step S4A, as shown in FIG. 9, the wafer 200 with DAF is cut from the DAF202 side at a position corresponding to the planned division line 204. In FIG. 9, the dicing tape 207 is formed by laminating the base material layer 207A and the adhesive layer 207B, and the adhesive layer 207B is adhered to the wafer 201.

In this configuration, the first cutting blade 21B cuts into the depth D1 leading to the wafer 201 to form a first cutting groove 210 that divides the DAF 202. As a result, on the surface side of the wafer 201, an uncut portion 212 having a depth (thickness) D2 is formed below the first cutting groove 210. As described above, since the DAF202 is formed by mixing metal particles with the resin material, when the DAF202 is cut by the first cutting blade 21B, the first cutting blade 21B made of the resin material or the metal particles It is expected that clogging will occur. In the present embodiment, the first cutting blade 21B sufficiently cuts into the wafer 201 to a depth D1 reaching the wafer 201, whereby a part of the resin and metal adhering to the abrasive grains is removed, and the bond is appropriately formed. Abrasive grains that are worn and adhered with resin or metal are shed, and spontaneous blades from which new abrasive grains are projected are promoted. That is, the first cutting blade 21B can obtain a dressing effect, and can prevent the first cutting blade 21B from being clogged with a resin material or metal particles. Here, if the cutting depth D1 of the first cutting groove 210 is too deep, the rigidity of the uncut portion 212 becomes insufficient, and cracks may occur on the surface side of the wafer 201. Therefore, the depth D1 of the first cutting groove 210 corresponds to the thickness of the wafer 201 of the wafer 200 with DAF within a range that satisfies the prevention of cracks in the wafer 201 and the dressing effect of the first cutting blade 21B. Is set. For example, the depth D1 of the first cutting groove 210 is set to about 20 to 300 [μm], and the depth D2 of the uncut portion 212 is set to about 20 to 500 [μm].

In the second cutting step S4B, as shown in FIG. 10, the chuck table 1 is fed in the cutting feed direction (X1 direction in the figure) while rotating the second cutting blade 21C in a predetermined direction (arrow R1 direction in the figure). .. As a result, the second cutting blade 21C cuts the wafer 200 with DAF along the scheduled division line 204 (FIG. 11) in a so-called down cut in which machining proceeds while cutting downward with respect to the wafer 200 with DAF.

The second cutting blade 21C is a blade in which finer abrasive grains than the above-mentioned first cutting blade 21B, for example, mesh-sized abrasive grains of # 2000 to # 5000 are fixed to the base by electroforming. In the second cutting step S4B, as shown in FIG. 11, a second cutting groove 211 having a depth reaching the adhesive layer 207B of the dicing tape 207 is formed at the groove bottom of the first cutting groove 210. The second cutting groove 211 is formed by cutting the uncut portion 212 described above, and cuts the wafer 200 with DAF along the scheduled division line 204. As a result, the wafer 200 with DAF can be easily divided into device chips.

The groove width W2 of the second cutting groove 211 is smaller than the groove width W1 of the first cutting groove 210. This is because the second cutting blade 21C uses a blade having a thinner blade thickness than the first cutting blade 21B. Since the second cutting step S4B is a step of cutting the wafer 201 which is relatively easy to cut, the wafer 201 can be easily cut even if the blade thickness of the second cutting blade 21C is thinner than that of the first cutting blade 21B. Can be cut. The blade thickness of the second cutting blade 21C can be appropriately changed according to the width of the planned division line 204 and the like. Further, in general, in a so-called downcut in which the cutting blade cuts downward with respect to the workpiece and the machining proceeds, the lower surface side of the workpiece is supported by the glue of the dicing tape, so that the surface side of the workpiece is on the upper surface side. In comparison, chipping tends to occur more on the lower surface side. In the present embodiment, the surface 203 side of the wafer 201 on which the device 205 is formed is the lower surface, so it is important to suppress chipping on the lower surface (surface 203 side). Further, when the DAF and the wafer are cut at the same time as compared with cutting (dicing) the wafer of silicon alone, chipping is greatly generated due to the influence of clogging of the cutting blade when cutting the DAF. As in the present embodiment, the first cutting step S4A, which divides the DAF 202 by cutting into the depth D1 reaching the waha 201 with the first cutting blade 21B and forms the uncut portion 212 on the surface side of the waha 201, After performing the first cutting step S4A, the second cutting blade 21C, which is thinner than the first cutting blade 21B, is cut into the depth D2 reaching the dicing tape 207 and along the planned division line 204. By executing the second cutting step S4B for cutting the uncut portion 212, the thickness of the apparent cutting object (work) in the first cutting step S4A and the second cutting step S4B becomes thin, so that the machining load is increased. It can be lowered and the chipping generated on the surface 203 of the waha 201 can be suppressed.

As described above, in the present embodiment, a wafer 201 having a plurality of intersecting planned division lines 204 and a device 205 formed in each region of the surface 203 partitioned by the planned division lines 204, and a wafer 201. It is a processing method of a wafer 200 with a DAF provided with a DAF 202 formed on the back surface 206 of the wafer 201, and a dicing tape 207 is attached to the wafer 201 side of the wafer 200 with a DAF to expose the DAF 202. After performing the attaching step S1 and the tape attaching step S1, the adhesive layer removing step S2 for removing the DAF202 on the outer periphery of the wafer 200 with DAF to form the exposed portion 201A in which the back surface of the wafer 201 is exposed. After performing the adhesive layer removing step S2, the street detection step S3 for detecting the planned division line 204 via the exposed portion 201A by using the second imaging means 26 that irradiates the infrared rays transmitted through the wafer 201. After performing the street detection step S3, a cutting step S4 for cutting the wafer 200 with a DAF from the DAF 202 of the wafer 200 with a DAF by the cutting blade 21 is provided along the detected line 204 to be divided.

According to this embodiment, the cutting blade 21 is cut into the wafer 200 with DAF with the DAF 202 facing up. When the wafer 200 with DAF is cut with the DAF202 down as in the past, the DAF202 is supported by the soft glue of the dicing tape, so that the metal particles and the resin material contained in the DAF202 are stretched respectively. There is a risk that the wafer 201 will be cracked and cracked. On the other hand, when the cutting blade 21 is cut into the wafer 200 with DAF with the DAF 202 facing up, the DAF 202 is in a state of being supported by the wafer 201, so that metal particles and metal particles are generated as the cutting blade 21 rotates. The resin material is difficult to be stretched, and the occurrence of cracks in the wafer 201 can be suppressed. Therefore, the risk of damage to the device 205 and the device chip can be reduced. Further, in the present embodiment, since the adhesive layer removing step S2 for removing the DAF202 on the outer periphery of the wafer 200 with DAF to form the exposed portion 201A in which the back surface of the wafer 201 is exposed is provided, the second image pickup is an infrared camera. By passing through the exposed portion 201A using the means 26, the scheduled division line 204 can be easily detected.

Further, in the present embodiment, in the cutting step S4, the DAF 202 is divided by cutting into the depth D1 reaching the waha 201 with the first cutting blade 21B, and the uncut portion 212 is formed on the surface side of the waha 201. After performing the cutting step S4A and the first cutting step S4A, the second cutting blade 21C having a thinner blade thickness than the first cutting blade 21B is scheduled to be divided while being cut into the depth D2 reaching the dicing tape 207. A second cutting step S4B for cutting the uncut portion 212 along the line 204 is provided. According to the present embodiment, the first cutting step S4A prevents clogging of the first cutting blade 21B for cutting the DAF 202 and prevention of cracks on the surface side of the wafer 201 due to poor rigidity of the uncut portion 212. In addition, the uncut portion 212 can be cut by the second cutting step S4B, and the wafer 200 with DAF can be easily cut along the planned division line 204.

Further, since the second cutting blade 21C used in the second cutting step S4B contains finer abrasive grains than the abrasive grains contained in the first cutting blade 21B, the uncut portion 212 can be smoothly cut. It is possible to prevent cracks from occurring when cutting the uncut portion 212.

Next, a modification will be described. FIG. 12 is a perspective view of the surface side of a wafer with a die attach film, which is a modified example of the workpiece to be processed. The wafer 250 with DAF, which is the workpiece, has a different configuration from the wafer 200 with DAF described above in that the size of the DAF 222 is formed to be smaller than that of the wafer 201. The same configuration as that of the wafer 200 with DAF is designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 12, the wafer 250 with a DAF includes the above-mentioned wafer 201 and a DAF 222 formed on the back surface 206 side of the wafer 201. The DAF222 is formed in the shape of a disk having a diameter smaller than the size of the wafer 201. Further, the DAF 222 is formed on the back surface 206 of the wafer 201 corresponding to the device region 221 formed on the front surface 203 of the wafer 201. This device area 221 is an area in which the above-mentioned plurality of devices 205 are formed. As described above, the DAF 222 is formed on the back surface 206 of the wafer 201 corresponding to the device region 221 and is formed in a disk shape having a diameter smaller than the size of the wafer 201. Therefore, the DAF 222 is formed on the outer peripheral portion of the back surface 206 of the wafer 201. The exposed portion 201A in which the DAF222 is not formed and the wafer 201 is exposed exists from the beginning.

In this wafer 250 with DAF, the line to be divided is planned to be divided by passing through the exposed portion 201A by using the second imaging means 26 which is an infrared camera without carrying out the adhesive layer removing step S2 as in the above-described embodiment. 204 can be easily detected. Also, when cutting (dicing) a wafer with DAF with the DAF (adhesive layer) facing down, that is, the DAF (adhesive layer) side is attached to the dicing tape, the outer circumference of the wafer can be cut (diced) by simply mounting the tape normally. Adhesion of the exposed portion where the DAF is not formed on the side to the dicing tape is loose, and chip skipping of the divided device chips is likely to occur during cutting. In this modification, by cutting the cutting blade 21 into the wafer 250 with DAF with the DAF222 facing up, the cutting blade 21 can be firmly adhered to the surface 203 of the wafer 201 and the dicing tape, so that the tip of the divided device chip is skipped. Can be suppressed.

The present invention is not limited to the above embodiment. That is, it can be variously modified and carried out within a range that does not deviate from the gist of the present invention. For example, in the present embodiment, the cutting step S4 is divided into the first cutting step S4A and the second cutting step S4B, but the wafer 200 with DAF can be cut by one cutting.

1 Chuck table 2 Cutting means 21 Cutting blade 21A Grinding blade 21B First cutting blade 21C Second cutting blade 25 First imaging means 26 Second imaging means 100 Cutting device 200, 250 Waha with die attach film (Wah with DAF) Work piece)
201 Wafer 201A Exposed part 202, 222 Diatach film (DAF; adhesive layer)
203 Surface 204 Scheduled division line (street)
205 Device 206 Back side 207 Dicing tape (tape)
207A Base material layer 207B Adhesive layer 208 Circular frame 209 Frame unit 210 1st cutting groove 211 2nd cutting groove 212 Uncut part 221 Device area

Claims (5)

Machining a work piece comprising a wafer having a plurality of intersecting streets and devices formed in each region of the surface partitioned by the streets, and an adhesive layer formed on the back surface of the wafer. It ’s a method,
A tape application step in which a tape is applied to the surface side of the work piece to expose the adhesive layer, and a tape application step.
After performing the tape application step, the adhesive layer removing step of removing the adhesive layer on the outer periphery of the workpiece to form an exposed portion where the back surface of the wafer is exposed.
After performing the adhesive layer removing step, a street detection step of detecting a street through the exposed portion using an infrared camera transmitted through the wafer, and a street detection step.
After performing the street detection step, a cutting step of cutting the workpiece from the back surface of the workpiece along the detected street with a cutting blade, and
A method of processing a workpiece equipped with. A wafer having a plurality of streets intersecting the surface and a device area in which a device is formed in each area partitioned by the streets, and at least smaller than the size of the wafer formed on the back surface of the wafer corresponding to the device area. A method of processing a workpiece with a sized adhesive layer.
A tape application step in which a tape is applied to the surface side of the work piece to expose the adhesive layer, and a tape application step.
After performing the tape application step, a street detection step of detecting a street through an area where the back surface of the wafer is exposed on the outer periphery of the adhesive layer using an infrared camera that transmits the wafer, and a street detection step.
After performing the street detection step, a cutting step of cutting the workpiece from the back surface of the workpiece along the detected street with a cutting blade, and
A method of processing a workpiece equipped with. The cutting step includes a first cutting step in which the adhesive layer is divided by cutting to a depth reaching the wafer with a first cutting blade and an uncut portion is formed on the surface side of the wafer.
After performing the first cutting step, the uncut portion is cut along the street while cutting the second cutting blade, which is thinner than the first cutting blade, to the depth reaching the tape. The second cutting step to be done,
The method for processing a workpiece according to claim 1 or 2, wherein the work piece is processed. The method for processing a workpiece according to claim 3, wherein the second cutting blade used in the second cutting step contains abrasive grains finer than the abrasive grains contained in the first cutting blade. The method for processing a workpiece according to any one of claims 1 to 4, wherein the adhesive layer is composed of metal particles and a resin.

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