JP2019186491A - Processing method for work piece - Google Patents

Abstract

To reduce possibilities of damage to a device and device chips.SOLUTION: A processing method for a wafer: comprising a wafer having a plurality of dividing lines crossing one another and devices formed in respective areas of a surface sectioned by the dividing lines; and a DAF formed on a rear surface of the wafer, comprises: a tape sticking step S1 in which dicing tape is stuck to a wafer side of the DAF-having wafer and the DAF is exposed; an adhesive layer removal step S2 in which an exposure part is formed such that the DAF on an outer periphery of the DAF-having wafer is removed to expose the rear surface of the wafer; a street detection step S3 in which the dividing lines are detected via the exposure part by using second imaging means composed of a camera for infrared ray transmissive through the wafer; and a cutting step S4 in which the DAF-having wafer is cut with a cutting blade from the DAF of the DAF-having wafer along the detected dividing lines.SELECTED DRAWING: Figure 3

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) with 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 workpiece, generally the adhesive layer side of the workpiece is 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 reaching the tape. The semiconductor device with the adhesive layer is formed by cutting the workpiece by cutting the workpiece (see, for example, Patent Document 1). On the other hand, power semiconductor devices and in-vehicle semiconductor devices are mounted on a substrate with solder. In recent years, since the use of lead has been restricted, for example, a die attach film as a conductive adhesive layer mixed with metal particles such as silver has also started to be used (see, for example, Patent Document 2).

JP 2006-063060 A JP 2017-002181 A

  However, the adhesive layer described above is formed of a resin material (ductility material) having ductility such as polyimide resin, epoxy resin, acrylic resin fat, and the like. For this reason, when the adhesive layer having ductility is cut with a cutting blade, the adhesive layer may be stretched along with the rotation of the cutting blade, and a crack may be generated at the interface with the wafer. If the crack occurs, the adhesive layer may be peeled off, or the crack may be extended to cause a problem of damaging the device. In particular, in the case where the adhesive layer is a conductive adhesive layer in which ductile metal particles (ductile material) are mixed in a ductile resin material, it is assumed that the above-described problem is remarkably generated. .

  This invention is made | formed in view of the above, Comprising: It aims at providing the processing method of the to-be-processed object which can reduce the possibility of damaging a device or a device chip.

  In order to solve the above-described problems and achieve the object, the present invention provides a wafer having a plurality of intersecting streets and devices respectively formed in each region of a surface partitioned by the streets, An adhesive layer formed on the back surface, and a processing method of the workpiece, the tape attaching step of sticking a tape to the surface side of the workpiece and exposing the adhesive layer; After performing the tape sticking step, the adhesive layer removing step of removing the adhesive layer on the outer periphery of the workpiece to form an exposed portion exposing the back surface of the wafer; and removing the adhesive layer After performing the step, a street detection step of detecting a street through the exposed portion using an infrared camera that passes through the wafer, and after performing the street detection step, along the detected street A cutting step of cutting the workpiece by the cutting blade from the rear surface of the workpiece, in which with a.

  According to this configuration, since the workpiece is cut from the adhesive layer with the cutting blade with the adhesive layer on the back side of the workpiece facing up, the adhesive layer is supported by the wafer. The adhesive layer is not easily stretched with the rotation of the cutting blade, and the occurrence of cracks in the wafer can be suppressed. For this reason, the possibility of damage to the device or the device chip can be reduced. Further, since the adhesive layer is removed by 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, the exposure is performed using an infrared camera in the street detection step. The street can be easily detected by passing through the section.

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

  According to this configuration, since the workpiece is cut from the adhesive layer with the cutting blade with the adhesive layer on the back side of the workpiece facing up, the adhesive layer is supported by the wafer. The adhesive layer is not easily stretched with the rotation of the cutting blade, and the occurrence of cracks in the wafer can be suppressed. For this reason, the possibility of damage to the device or the device chip can be reduced. In addition, since the workpiece includes an adhesive layer formed on at least the back surface of the wafer corresponding to the device region and having a size smaller than the wafer, the 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 periphery of the wafer using an infrared camera.

  In the configuration described above, the cutting step includes a first cutting step of cutting the adhesive layer by cutting to a depth reaching the wafer with a first cutting blade and forming an uncut portion on the surface side of the wafer. And after the first cutting step, the uncut portion along the street while cutting the second cutting blade having a thickness smaller than that of the first cutting blade to a depth reaching the tape. And a second cutting step for cutting.

  Further, the second cutting blade used in the second cutting step may include finer abrasive grains than the abrasive grains included in the first cutting blade. Moreover, this adhesive bond layer is good also as a structure which consists of a metal particle and resin.

  According to the present invention, the workpiece is cut from the adhesive layer with the cutting blade in a state where the adhesive layer on the back surface side of the workpiece is facing upward, so that the adhesive layer is supported by the wafer. The adhesive layer is not easily stretched with the rotation of the cutting blade, and the occurrence of cracks in the wafer can be suppressed. For this reason, the possibility of damage to the device or the device chip can be reduced.

FIG. 1 is a perspective view of a surface side of a wafer with a die attach film, which is an example of a workpiece to be processed. 2 is a perspective view of the back side of the wafer with a die attach film shown in FIG. FIG. 3 is a flowchart showing a procedure of a workpiece processing method according to the present embodiment. FIG. 4 is a perspective view showing an outline of the tape attaching step. FIG. 5 is a perspective view showing an example of a cutting device for processing 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 the wafer with DAF showing the first cutting grooves 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 the wafer with DAF showing the second cutting groove formed on 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 modification of the workpiece to be processed.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

  The processing method of the to-be-processed object which concerns on this embodiment is demonstrated based on drawing. FIG. 1 is a perspective view of a surface side of a wafer with a die attach film, which is an example of a workpiece to be processed. 2 is a perspective view of the back side of the wafer with a die attach film shown in FIG.

The processing method of the workpiece according to the present embodiment is a method of cutting a wafer 200 with a die attach film (hereinafter referred to as a wafer with DAF) 200 as a workpiece and dividing it into individual device chips. The wafer 200 with a DAF includes 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, for example, a disk-shaped semiconductor wafer or optical device wafer based on silicon, gallium arsenide (GaAs) or the like, a glass or sapphire (Al ₂ O ₃ ) -based plate-like inorganic material substrate, or the like. Various processed materials. As shown in FIG. 1, the surface of the wafer 201 is divided into a plurality of regions partitioned by a plurality of intersecting scheduled lines (streets) 204, such as IC (Integrated Circuit) and LSI (Large Scale Integration). A device 205 is formed.

  The DAF 202 includes metal particles (conductive particles) mixed in a ductile resin material such as polyimide resin, epoxy resin, acrylic resin fat, and the like, and is formed on the back surface 206 side of the wafer 201. In the present embodiment, the DAF 202 is formed in a disk shape 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]. Moreover, it is preferable that the average particle diameter of a metal particle is 1-10 [micrometers]. The DAF 202 may be formed by forming a resin material mixed with metal particles into a film (sheet shape), and the DAF 202 may be adhered to the back surface 206 of the wafer 201. Alternatively, the resin material mixed with metal particles may be used. The DAF 202 may be formed by coating the back surface 206 of the wafer 201.

  FIG. 3 is a flowchart showing a procedure of a workpiece processing method according to the present embodiment. FIG. 4 is a perspective view showing an outline of the tape attaching step. First, a dicing tape (tape) 207 is attached to the surface 203 side of the wafer 200 with DAF as a workpiece (tape attaching step S1). Specifically, as shown in FIG. 4, a frame unit 209 is formed. The frame unit 209 supports the wafer 200 with DAF, 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 dicing tape 207. And 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 for processing a workpiece. In the present embodiment, the cutting apparatus 100 performs an adhesive layer removal step S2, a street detection step S3, and a cutting step S4 on the DAF wafer 200 of the frame unit 209. As shown in FIG. 5, the cutting apparatus 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. Means 6, a cassette elevator 7, and a cleaning means 8 are provided.

  The chuck table 1 is formed in a disc 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 about 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 in the vertical direction of the chuck table 1 and is formed flat with respect to the horizontal plane. The holding surface 11 is made of, for example, porous ceramic, and sucks and holds the DAF wafer 200 of the frame unit 209 through the dicing tape 207 by a 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 the wafer 200 with 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 a cutting grindstone that has a cutting blade in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are hardened with a bond material such as metal or resin, and is formed in an extremely thin disk shape and in an annular shape. . 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 so as to be rotatable 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 imaging means 25 is a camera having an imaging element such as a CCD (Charge Coupled Device) image sensor. The second imaging means 26 is, for example, an infrared camera having an infrared irradiation unit (not shown) that irradiates infrared rays and an imaging element (infrared CCD) that outputs an electrical signal corresponding to the infrared rays. Based on the image acquired by the first image pickup means 25 or the second image pickup means 26, the planned division line 204 can be detected.

  The X-axis moving unit 3 feeds the chuck table 1 and the cutting unit 2 relatively in the cutting feed direction. The X-axis moving unit 3 includes, for example, a pulse motor, a ball screw, a guide rail, and the like. The X-axis moving unit 3 moves the moving base 31 on 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 index feed direction and the cut feed direction. The portal frame 4 is erected on the apparatus main body 101 across the X-axis moving means 3 in the index feeding direction.

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

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

  The cassette elevator 7 supports the apparatus main body 101 so that the cassette 71 in which a plurality of frame units 209 are accommodated can be moved up and down in the vertical direction. The cleaning unit 8 cleans the frame unit 209 cut by the cutting unit 2 by holding it with the spinner table 81.

  Returning to the flowchart of FIG. 3 again, the continuation of the procedure of the workpiece processing method 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 the wafer with DAF showing the first cutting grooves 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 the wafer with DAF showing the second cutting groove formed on the first cutting groove in the second cutting step.

  After performing the above-mentioned tape sticking step S1, 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 apparatus 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 (in the direction of the arrow R1), the grinding blade 21A is cut into the DAF 202 on the outer periphery of the wafer 200 with DAF. DAF 202 is removed. As a result, an exposed portion 201A in which the back surface side of the wafer 201 is exposed is formed. The grinding blade 21A is formed to be thicker than a cutting blade used in a 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 DAF wafer 200. The The exposed portion 201A only needs to have a width that allows the planned division line 204 to be detected in a street detection step S3 to be described later. The exposed portion 201A is appropriately changed depending on the arrangement relationship between the division planned line 204 and the device 205 on the wafer 201. Can do. Further, the exposed portion 201A may be formed by cutting a plurality of rotations instead of forming the chuck table 1 once. For example, using the grinding blade 21A having a width of 1 mm, the chuck table 1 is rotated once and cut into an annular shape, and then the grinding blade 21A is moved in the radial direction of the wafer 200 with DAF. And the exposed part 201A of a predetermined width (for example, 3 mm) can be formed by repeating the operation | movement which rotates the chuck table 1 again and cuts cyclically | annularly.

  Next, the division line 204 is detected via the exposed portion 201A (street detection step S3). Specifically, as shown in FIG. 7, the division line 204 on the surface 203 side is detected using the second imaging unit 26 through the exposed portion 201 </ b> A exposed at the outer peripheral edge. The second imaging means 26 is an infrared camera as described above, and images the planned division line 204 formed on the front surface 203 of the wafer 201 from the rear surface side of the wafer 201. In general, an infrared camera can obtain a clearer captured image as the thickness of the imaging object is thinner. In the configuration in which the DAF is provided on the back surface 206 of the wafer 201, even if this DAF is a non-conductive DAF that does not mix metal particles, the thickness to be transmitted by the infrared camera is increased by the amount of the DAF. It becomes difficult to detect the division line 204 formed on the surface 203 of the 201. Further, in the configuration in which the metal particles are mixed in the resin material and the conductive DAF 202 is provided as in the present embodiment, infrared rays do not pass through the DAF 202, particularly the metal particles in the DAF 202. For this reason, it becomes more difficult to detect the division line 204 through the DAF 202 with the infrared camera. In this embodiment, the DAF 202 at the outer peripheral edge of the wafer 200 with DAF is removed to form an exposed portion 201A where the wafer 201 is exposed, so that infrared rays are transmitted through the exposed portion 201A which is a part of the wafer 201. The scheduled line 204 can be easily detected. The alignment for aligning the DAF wafer 200 and the cutting blade 21 of the cutting means 2 is performed according to the detected position of the division line 204.

  Next, the DAF wafer 200 is cut from the DAF 202 side along the detected division line 204 (cutting step S4). In the present embodiment, the cutting step S4 is performed in two stages, a first cutting step S4A and a 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 planned division line 204 (FIG. 9) in a so-called down cut in which the processing proceeds while cutting downward with respect to the wafer 200 with DAF.

  The first cutting blade 21B is a blade in which abrasive grains having a mesh size of # 1700 to # 3000 are fixed to the base by electroforming, for example. In the first cutting step S4A, as shown in FIG. 9, the DAF wafer 200 is cut from the DAF 202 side at a position corresponding to the planned division line 204. In FIG. 9, the dicing tape 207 is formed by laminating a base material layer 207 </ b> A and an adhesive layer 207 </ b> B, and the adhesive layer 207 </ b> B is bonded to the wafer 201.

  In this configuration, the first cutting blade 21 </ b> B forms a first cutting groove 210 that divides the DAF 202 by cutting to a depth D <b> 1 reaching the wafer 201. As a result, an uncut portion 212 having a depth (thickness) D <b> 2 is formed below the first cutting groove 210 on the front surface side of the wafer 201. As described above, since the DAF 202 is formed by mixing metal particles in a resin material, when the DAF 202 is cut by the first cutting blade 21B, the first cutting blade 21B made of the resin material or metal particles is used. It is assumed that clogging occurs. In the present embodiment, the first cutting blade 21B is sufficiently cut to the wafer 201 to the 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 moderately The abrasive grains to which the resin or metal is affixed are removed, and the self-generated blade from which new abrasive grains protrude is promoted. That is, the first cutting blade 21B can obtain a dress effect, and can prevent the first cutting blade 21B from being clogged with a resin material or metal particles. Here, if the cut depth D1 of the first cutting groove 210 is too deep, the rigidity of the uncut portion 212 becomes insufficient, and a crack may occur on the surface side of the wafer 201. For this reason, the depth D1 of the first cutting groove 210 corresponds to the thickness of the wafer 201 of the wafer 200 with DAF as long as the crack is prevented from occurring in the wafer 201 and the dressing effect of the first cutting blade 21B is satisfied. 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 the processing proceeds while cutting downward with respect to the wafer 200 with DAF.

  The second cutting blade 21C is a blade in which abrasive grains finer than the first cutting blade 21B described above, for example, abrasive grains having a mesh size of # 2000 to # 5000, are fixed to the base by electroforming. In the second cutting step S4B, as shown in FIG. 11, the second cutting groove 211 having a depth reaching the adhesive layer 207B of the dicing tape 207 is formed in the groove bottom of the first cutting groove 210. The second cutting groove 211 is formed by cutting the above-described uncut portion 212 and cuts the DAF-equipped wafer 200 along the planned division line 204. Thereby, 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 is a blade having a thinner blade thickness than the first cutting blade 21B. Since the second cutting step S4B is a process of cutting the wafer 201 that is relatively easy to cut, the wafer 201 can be easily formed even if the blade thickness of the second cutting blade 21C is smaller than that of the first cutting blade 21B. Can be cut. The blade thickness of the second cutting blade 21C can be changed as appropriate according to the width of the scheduled division line 204 and the like. Further, in general, in the so-called down cut in which the cutting blade advances while cutting downward with respect to the workpiece, the lower surface side of the workpiece is supported by the glue of the dicing tape. In comparison, chipping tends to occur greatly on the lower surface side. In the present embodiment, since the surface 203 side of the wafer 201 on which the device 205 is formed becomes the lower surface, it is important to suppress chipping on the lower surface (front surface 203 side). Further, when cutting a DAF and a wafer at the same time as compared with cutting (dicing) a single silicon wafer, chipping is greatly generated due to clogging of a cutting blade when the DAF is cut. As in the present embodiment, the first cutting step S4A for cutting the DAF 202 by cutting to the depth D1 reaching the wafer 201 with the first cutting blade 21B and forming the uncut portion 212 on the surface side of the wafer 201; After performing the first cutting step S4A, the second cutting blade 21C having a thickness smaller than that of the first cutting blade 21B is cut into the depth D2 reaching the dicing tape 207 along the planned division line 204. By executing the second cutting step S4B for cutting the uncut portion 212, the apparent thickness of the cutting object (workpiece) in the first cutting step S4A and the second cutting step S4B is reduced, so that the processing load is reduced. The chipping that occurs on the surface 203 of the wafer 201 can be suppressed.

  As described above, the present embodiment includes a wafer 201 having a plurality of intersecting division lines 204 and devices 205 respectively formed in each region of the surface 203 partitioned by the division lines 204. A method of processing a wafer 200 with a DAF provided with a DAF 202 formed on the back surface 206 of the wafer 201, wherein 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 forming the exposed portion 201A in which the back surface of the wafer 201 is exposed by removing the DAF 202 on the outer periphery of the wafer 200 with DAF. And after passing through the adhesive layer removal step S2, the wafer 201 passes therethrough. After performing the street detection step S3 for detecting the division planned line 204 through the exposed portion 201A using the second imaging means 26 that irradiates the outside line, and the street detection step S3, the detected division planned line 204 is detected. A cutting step S4 of cutting the DAF wafer 200 from the DAF 202 of the DAF wafer 200 with the cutting blade 21 is provided.

  According to the present embodiment, the cutting blade 21 is cut into the DAF wafer 200 with the DAF 202 facing up. When the DAF wafer 200 is cut with the DAF 202 facing down as in the prior art, since the DAF 202 is supported by the soft glue of the dicing tape, the metal particles and the resin material contained in the DAF 202 are each stretched. As a result, the wafer 201 may be cracked. On the other hand, when the cutting blade 21 is cut into the DAF wafer 200 with the DAF 202 facing up, the DAF 202 is supported by the wafer 201, so that metal particles and The resin material is not easily stretched, and the occurrence of cracks in the wafer 201 can be suppressed. For this reason, the possibility of damage to the device 205 and the device chip can be reduced. In the present embodiment, since the DAF 202 on the outer periphery of the wafer 200 with DAF is removed to form an exposed portion 201A in which the back surface of the wafer 201 is exposed, the second imaging that is an infrared camera is provided. By transmitting the exposed portion 201A using the means 26, the planned division line 204 can be easily detected.

  Further, in the present embodiment, the cutting step S4 is a first step of cutting the DAF 202 by cutting to the depth D1 reaching the wafer 201 with the first cutting blade 21B and forming the uncut portion 212 on the surface side of the wafer 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 cut into the depth D2 reaching the dicing tape 207, and the division is scheduled A second cutting step S4B for cutting the uncut portion 212 along the line 204. According to the present embodiment, the first cutting step S4A prevents clogging of the first cutting blade 21B that cuts the DAF 202 and prevents generation of cracks on the surface side of the wafer 201 due to poor rigidity of the uncut portion 212. In the second cutting step S4B, the uncut portion 212 can be cut, and the DAF wafer 200 can be easily cut along the scheduled division line 204.

  Furthermore, since the second cutting blade 21C used in the second cutting step S4B includes abrasive grains finer than the abrasive grains included in the first cutting blade 21B, the uncut portion 212 can be cut smoothly, It is possible to prevent a crack from being generated when the uncut portion 212 is cut.

  Next, a modified example will be described. FIG. 12 is a perspective view of the surface side of a wafer with a die attach film, which is a modification of the workpiece to be processed. The DAF wafer 250, which is the workpiece, differs from the above-described DAF wafer 200 in that the size of the DAF 222 is smaller than that of the wafer 201. About the same structure as the wafer 200 with DAF, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 12, the DAF-equipped wafer 250 includes the above-described wafer 201 and a DAF 222 formed on the back surface 206 side of the wafer 201. The DAF 222 is formed in a disk shape having a smaller diameter than the size of the wafer 201. 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. The device region 221 is a region where the plurality of devices 205 described above are formed. Thus, since 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 smaller diameter than the size of the wafer 201, the outer periphery of the back surface 206 of the wafer 201 has The DAF 222 is not formed, and there is an exposed portion 201A where the wafer 201 is exposed from the beginning.

  In the wafer 250 with DAF, the divided line is transmitted by passing through the exposed portion 201A using the second imaging unit 26 that is an infrared camera without performing the adhesive layer removing step S2 as in the above-described embodiment. 204 can be easily detected. In addition, when a DAF (adhesive layer) side is attached to a dicing tape and a wafer with DAF is cut (dicing) with the DAF (adhesive layer) facing down, the outer periphery of the wafer is simply mounted with a tape. Adhesion of the exposed portion where the DAF is not formed on the side to the dicing tape is sweet, and the chip of the device chip divided at the time of cutting tends to occur. In this modified example, the cutting blade 21 is cut into the wafer 250 with DAF with the DAF 222 facing up, so that the surface 203 of the wafer 201 and the dicing tape can be firmly bonded. Can be suppressed.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention. For example, in this 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.

DESCRIPTION OF SYMBOLS 1 Chuck table 2 Cutting means 21 Cutting blade 21A Grinding blade 21B 1st cutting blade 21C 2nd cutting blade 25 1st imaging means 26 2nd imaging means 100 Cutting apparatus 200, 250 Wafer with a die attach film (wafer with DAF) ; Workpiece)
201 Wafer 201A Exposed portion 202, 222 Die attach film (DAF; adhesive layer)
203 Surface 204 Scheduled line (street)
205 Device 206 Back side 207 Dicing tape (tape)
207A Base material layer 207B Adhesive layer 208 Annular frame 209 Frame unit 210 First cutting groove 211 Second cutting groove 212 Uncut portion 221 Device region

Claims (5)

Processing a workpiece comprising a wafer having a plurality of intersecting streets and a device formed in each area of the surface partitioned by the streets, and an adhesive layer formed on the back surface of the wafer A method,
A tape adhering step for adhering a tape to the surface side of the workpiece and exposing the adhesive layer;
After performing the tape sticking step, removing the adhesive layer on the outer periphery of the workpiece to form an exposed portion exposing the back surface of the wafer;
After performing the adhesive layer removal step, a street detection step of detecting a street through the exposed portion using an infrared camera that passes through the wafer;
A cutting step of cutting the workpiece with a cutting blade from the back surface of the workpiece along the detected street after the street detection step;
A processing method of a workpiece provided with A wafer having a plurality of streets intersecting the surface and a device area in which devices are formed in each area partitioned by the street, and at least smaller than the size of the wafer formed on the back surface of the wafer corresponding to the device area A workpiece processing method comprising: an adhesive layer having a size;
A tape adhering step for adhering a tape to the surface side of the workpiece to expose the adhesive layer;
After performing the tape adhering step, a street detecting step of detecting a street through an area where the back surface of the wafer is exposed at the outer periphery of the adhesive layer using an infrared camera that transmits the wafer;
A cutting step of cutting the workpiece with a cutting blade from the back surface of the workpiece along the detected street after the street detection step;
A processing method of a workpiece provided with The cutting step includes a first cutting step of cutting the adhesive layer by cutting to a depth reaching the wafer with a first cutting blade and forming a non-cut portion on the surface side of the wafer;
After performing the first cutting step, the remaining cutting portion is cut along the street while a second cutting blade having a thinner blade thickness than the first cutting blade is cut to a depth reaching the tape. A second cutting step,
The processing method of the workpiece of Claim 1 or 2 provided with these.   The method of processing a workpiece according to claim 3, wherein the second cutting blade used in the second cutting step includes abrasive grains smaller than the abrasive grains included in the first cutting blade.   The method for processing a workpiece according to claim 1, wherein the adhesive layer is made of metal particles and a resin.

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