Workpiece confirmation and processing methods

Abstract

The present invention provides a workpiece confirmation method and a processing method, and proposes a new technology for reliably and automatically distinguishing chipping or cracks on the back side of the workpiece based on a photographed image of the back side of the workpiece. The workpiece confirmation method confirms the back side (5b) of a workpiece that has been divided and whose back side is fixed to a belt (7) and whose front side (5a) is exposed. The workpiece confirmation method includes the following steps: a photographing step of photographing the workpiece from the back side (5b) through the belt (7) using an infrared camera (second photographing unit (106b)) to form a photographed image; and a detection step of detecting chipping (5c) and / or cracks (5d) generated on the back side (5n) based on the photographed image formed by the photographing step.

Description

Technical Field

[0001] The present invention relates to a method for checking the back surface of a divided workpiece, the back surface of which is fixed to a belt and the front surface is exposed. Background Art

[0002] It is known to determine whether or not the adjustment of the cutting tool is sufficient based on the state of chipping on the back surface in a pre-cutting step before dicing a semiconductor wafer as a plate-shaped workpiece.

[0003] This determination is performed by temporarily unloading the pre-cut workpiece from the processing apparatus and observing the back side of the workpiece. However, there is a known method that omits the unloading and observation.

[0004] In Patent Document 1, based on the positive correlation between the chipping state of the back side of the workpiece and the processing load received by the chuck table from the cutting tool, that is, the greater the processing load, the greater the back side chipping, the processing load acting on the chuck table is measured during pre-cutting, so that the chipping state of the back side during pre-cutting can be appropriately grasped based on the measured processing load.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-303367

[0006] Meanwhile, the workpiece after cutting is observed under a microscope to measure the size of chipping (chips) and cracks (crazing) to manage the processing quality. However, there is a strong demand for improvement in the conventional method.

[0007] That is, in order to measure chipping and cracks on the back side, it is necessary to perform a transfer operation (tape replacement operation) or pick up the chip by pulling it out and stick the front side of the chip to the tape to expose the back side before observation, which is complicated.

[0008] Therefore, a method of observing the divided workpieces attached to the tape by photographing them with a camera through the tape from the back side is also conceivable.

[0009] However, unlike the front side, even if a slight chipping or crack occurs on the back side, it will not be clearly visible in the captured image because the back side is attached to the tape. While it is not impossible to visually detect chipping or cracks, it is difficult to automatically detect chipping or cracks through image processing of captured images. Summary of the Invention

[0010] In view of the above, the present invention proposes a new technology for reliably and automatically identifying chipping or cracking on the back side of a workpiece based on a captured image of the back side of the workpiece.

[0011] According to one embodiment of the present invention, a method for confirming a workpiece is provided for confirming the back side of a workpiece whose back side is fixed to a belt and whose front side is exposed and which has been divided, wherein the method for confirming the workpiece has the following steps: a photographing step, in which an infrared camera is used to photograph the workpiece from the back side through the belt to form a photographed image; and a detection step, in which chipping and / or cracks generated on the back side are detected based on the photographed image formed by the photographing step.

[0012] In addition, in the imaging step, imaging is performed with the infrared camera focusing on the front surface of the workpiece.

[0013] In addition, a method for processing a workpiece is provided, wherein the method for processing the workpiece has the following steps: a pasting step of pasting the back side of the workpiece to a tape to expose the front side of the workpiece; a splitting step of splitting the workpiece to which the tape is pasted; a photographing step of photographing the workpiece from the back side of the workpiece through the tape using an infrared camera to form a photographed image; and a detection step of detecting chipping and / or cracks generated on the back side based on the photographed image formed by the photographing step.

[0014] According to the present invention, the back surface condition of the workpiece can be confirmed based on an image captured by an infrared camera through a belt from the back surface, thereby reducing working hours and achieving time reduction. In addition, by using an infrared camera, chipping or cracks on the back surface can be reliably detected, thereby improving the reliability of the inspection.

[0015] Furthermore, defects such as chipping and cracks appear dark in captured images due to low brightness. This allows for detection and measurement of chipping or crack size. Specifically, the captured image is multi-valued, and using the edges detected through edge detection as a reference, areas within a specified brightness range are detected as crack or chipping areas. Furthermore, the size of the crack or chip can be measured based on the number of pixels in this area.

[0016] Furthermore, a series of steps from the division of the workpiece to the detection of chipping and / or cracks on the back surface can be performed in a short time. Furthermore, the detection accuracy is high, thereby improving the reliability of the inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a perspective view schematically showing an object to be inspected.

[0018] Figure 2 This is a perspective view schematically showing an inspection object divided into devices.

[0019] Figure 3 It is a perspective view schematically showing a processing device including an inspection device.

[0020] Figure 4 It is a top view schematically showing a processing device including an inspection device.

[0021] Figure 5 It is a perspective view schematically showing an inspection device.

[0022] Figure 6 (A) is a perspective view schematically showing a mechanism for holding an object to be inspected. Figure 6 (B) is a perspective view schematically showing the imaging mechanism.

[0023] Figure 7 (A) is a top view schematically showing the placement portion, Figure 7 (B) is a cross-sectional view schematically showing the placement portion.

[0024] Figure 8 This is a cross-sectional view schematically showing the positional relationship between the inspection object holding mechanism, the imaging mechanism, and the inspection object when the inspection object is inspected.

[0025] Figure 9 Schematic diagram of the second shooting unit composed of an infrared camera.

[0026] Figure 10 This is a schematic diagram of the object being inspected viewed from the side.

[0027] Figure 11 (A) is a diagram showing an example of a captured image, Figure 11 (B) is a diagram schematically showing the shape of chipping when viewed from the side of the device.

[0028] Description of labels

[0029] 1: object to be inspected; 1a: front side; 1b: back side; 2: processing device; 3: spacing path; 3a: processing mark; 4: base; 5: device; 5a: front side; 5b: back side; 5c: chipping; 5d: crack; 5n: back side; 7: belt; 9: frame; 11: frame unit; 76: loading part; 76a: loading surface; 78: belt holding part; 78a: suction groove; 78b: belt suction holding surface; 82: shooting mechanism; 84: supporting structure; 106a: first shooting unit; 106b: second shooting unit; 201: objective lens unit; 202: infrared CCD; 203: light source; R1: infrared light; R2: infrared light. DETAILED DESCRIPTION

[0030] An embodiment of one aspect of the present invention will be described with reference to the drawings. The inspection apparatus of this embodiment can inspect a workpiece (processed object) processed by a processing apparatus by simultaneously imaging the inspection object from both the top and bottom surfaces.

[0031] First, let's describe the object to be inspected. For example, the object to be inspected is a roughly circular wafer made of materials such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductors. Alternatively, the object to be inspected may be a substrate made of materials such as sapphire, glass, or quartz. Furthermore, the object to be inspected may be a package substrate containing multiple device chips sealed with a molded resin or the like.

[0032] Figure 1 This is a perspective view schematically showing a wafer as an example of an inspection object 1. The front surface 1a of the inspection object 1 is divided, for example, by a plurality of intersecting predetermined dividing lines, called streets 3. Devices 5, such as ICs (Integrated Circuits) and LSIs (Large-Scale Integrated Circuits), are formed in each area of ​​the front surface 1a of the wafer as the inspection object 1, divided by the streets 3. When the wafer is divided along the streets 3, individual device chips are formed.

[0033] To divide the inspection object 1, for example, a laser processing device is used that irradiates the inspection object 1 with a laser beam along the streets 3 to perform laser processing on the inspection object 1. Alternatively, a cutting device that can cut the inspection object 1 along the streets 3 using an annular cutting tool is used.

[0034] Before the object 1 is carried into a cutting device or a laser processing device, Figure 1 As shown, the inspection object 1 is integrated with the annular frame 9 and the tape 7 attached so as to seal the opening of the frame 9 to form a frame unit 11. The inspection object 1 attached with the tape 7 and mounted on the frame 9 by the tape 7 is carried into the processing device in this state for processing.

[0035] Figure 2 The state of the inspection object 1 after being processed by a processing device and divided into devices 5, 5 is shown. In this example, the state of cutting by a blade is shown.

[0036] In order to confirm that the object 1 to be inspected has been properly processed along the partitions 3, the inspection device of this embodiment photographs the processed portion of the object 1 while inspecting the object 1. For example, the inspection device inspects the object 1 along the partitions 3 to investigate the location of processing marks, the shape and size of defects called chipping formed in the object 1 along the processing marks, their distribution, and cracks (crazing). Furthermore, the size of the device chips formed by dividing the object 1 to be inspected is confirmed. However, the use of the inspection device is not limited to this.

[0037] Hereinafter, this embodiment will be described using as an example a case where the inspection object 1 is a wafer having a plurality of devices 5 formed thereon and divided along the streets 3. However, the inspection object 1 is not limited thereto. The inspection object 1 inspected by the inspection apparatus of this embodiment may also be processed without passing through a processing device or the like.

[0038] The inspection apparatus of this embodiment is used by being assembled in, for example, a processing apparatus having a processing unit that processes the inspection object 1. However, the inspection apparatus may not be assembled in the processing apparatus but may be independent. Figure 3 It is a perspective view schematically showing a processing device 2 incorporating the inspection device of this embodiment.

[0039] The processing device 2 includes a base 4 that supports various components. A cassette support 6 that can be raised and lowered is provided at a front corner of the base 4. A cassette that houses a plurality of frame units 11 is placed on the upper surface of the cassette support 6.

[0040] A rectangular opening 10, elongated in the X-axis direction (the processing feed direction), is formed on the upper surface of the base 4, adjacent to the cassette support 6. Disposed within the opening 10 are a workpiece holding unit 14, an X-axis moving mechanism (not shown) for moving a movable table 12 on which the workpiece holding unit 14 is mounted in the X-axis direction, and a dust and drip proof cover 10a covering the X-axis moving mechanism.

[0041] The processing device 2 is provided with a transport unit 16 for loading and unloading the frame unit 11 stored in the cassette placed on the cassette support table 6. The transport unit 16 includes a pair of guide rails 18 arranged on the front surface of the upright portion of the base 4 and parallel to the Y-axis direction. A movable body 20 is slidably mounted on the pair of guide rails 18. A nut portion (not shown) is provided on the rear surface side of the movable body 20, and a ball screw 22 parallel to the guide rails 18 is screwed into the nut portion.

[0042] A pulse motor 24 is connected to one end of the ball screw 22. When the pulse motor 24 rotates the ball screw 22, the movable body 20 moves in the Y-axis direction along the guide rail 18. An arm 26 extending in the X-axis direction is connected to the lower end of the movable body 20 via a lifting mechanism. A plurality of suction portions 28 are provided on the lower surface of the arm 26, corresponding to the size of the frame 9. In addition, a push-pull mechanism 30 is provided at the center of the arm 26, facing the cartridge support table 6.

[0043] A pair of transport rails 8 are provided on the upper surface of the base 4 so as to straddle the opening 10. The pair of transport rails 8 are spaced apart from each other by a width smaller than the diameter of the frame 9 and are movable in directions away from each other.

[0044] The transport unit 16 is movable in the Y-axis direction, and the front end of the push-pull mechanism 30 is inserted into the cassette placed on the cassette support table 6 to grasp the frame 9 of the frame unit 11 housed in the cassette. When the push-pull mechanism 30 grasps the frame 9 and the arm 26 moves in the opposite direction along the Y-axis, the frame unit 11 is pulled out onto the pair of transport rails 8.

[0045] Then, the push-pull mechanism 30 releases its grip on the frame 9, allowing the suction portion 28 of the transport unit 16 to contact the frame 9 from above, thereby attracting and holding the frame 9. Furthermore, the frame unit 11 is lifted upward from the transport rails 8, widening the gap between the pair of transport rails 8 and lowering the frame unit 11, thereby transporting it onto the workpiece holding unit 14.

[0046] The workpiece holding unit 14 is, for example, a chuck table that holds the inspection object 1 (wafer). A porous member is disposed on the upper surface of the workpiece holding unit 14, and the upper surface of this porous member serves as a holding surface for the frame unit 11. This porous member is connected to a suction source (not shown) via a suction path (not shown) formed within the workpiece holding unit 14. The workpiece holding unit 14 is capable of suctioning and holding the frame unit 11.

[0047] Figure 4 This is a top view schematically illustrating the structure of a processing device 2. The processing device 2 includes a processing unit 32 that processes an inspection object 1 as a workpiece. The processing unit 32 is a cutting unit and includes, for example, an annular cutting tool 34; a spindle housing 36 that houses a spindle, which is inserted through a through-hole in the cutting tool 34 and serves as a rotation axis for rotating the cutting tool 34; and a motor (not shown) that rotates the spindle. When the rotating cutting tool 34 cuts into the workpiece held by the workpiece holding unit 14, the workpiece is cut.

[0048] However, in Figure 4 The processing device 2 shown is equipped with two processing units 32 for cutting the inspection object 1, but the processing device 2 is not limited to this. For example, the processing device 2 may have a single processing unit 32. Alternatively, the processing unit 32 may be a laser processing unit for laser processing the inspection object 1.

[0049] like Figure 3 and Figure 4As shown, the processing device 2 has an opening 38 on the upper surface of the base 4, adjacent to the opening 10. A cleaning device 40 is provided within the opening 38, which is capable of cleaning the inspection object 1 processed by the processing unit 32. The inspection object 1 after processing is transported to the cleaning table of the cleaning device 40 by the transport unit 16 or the like. The cleaning table, on which the inspection object 1 is placed, is rotated at high speed while high-pressure cleaning water is sprayed onto the inspection object 1 from a nozzle (not shown), thereby cleaning the inspection object 1.

[0050] Furthermore, the inspection object 1 can be loaded into the cleaning device 40 by a transport unit 42. The transport unit 42 includes a pair of guide rails 44 arranged on the front surface of the upright portion of the base 4 and parallel to the Y-axis direction. A moving body 46 is slidably mounted on the pair of guide rails 44. A nut portion (not shown) is provided on the rear surface side of the moving body 46, and a ball screw 48 parallel to the guide rails 44 is screwed into the nut portion.

[0051] A pulse motor 50 is connected to one end of the ball screw 48. When the pulse motor 50 rotates the ball screw 48, the movable body 46 moves in the Y-axis direction along the guide rail 44. An arm 52 is connected to the lower end of the movable body 46 via a lifting mechanism. The arm 52 is provided with a holding mechanism 54, which is equipped with a plurality of suction units (not shown) arranged to correspond to the size of the frame 9.

[0052] For example, a plurality of devices 5 are formed on the front surface of an inspection object 1. When the inspection object 1 is divided into individual device chips by the processing unit 32 of the processing device 2, the individual device chips are formed. In order to confirm that the inspection object 1 has been properly processed, the inspection device 56 of this embodiment is used to inspect the processed inspection object 1.

[0053] After the inspection object 1 is cleaned by the cleaning device 40, the inspection object 1 is held by the holding mechanism 54 and transported to the inspection device 56 by the transport unit 42. Alternatively, the inspection object 1 may be transported to the inspection device 56 by the transport unit 16 instead of the transport unit 42. Here, when the orientation of the cleaning table is pre-adjusted before the inspection object 1 is held by the transport units 16 and 42, the orientation of the inspection object 1 transported to the inspection device 56 is aligned with the prescribed orientation.

[0054] For example, the inspection apparatus 56 inspects the object 1 along a dividing groove formed in the object 1, examining the shape, size, distribution, and cracks (fracturing) of defects known as chipping formed along the dividing groove in the object 1. Furthermore, the size of the device chips formed by dividing the object 1 is confirmed.

[0055] The inspection device 56 is an inspection device that can simultaneously observe the same position of the inspection object 1 from both the upper surface side (front surface 1a side) and the lower surface side (back surface 1b side). Figure 3 As shown in FIG, the inspection device 56 is assembled to the processing device 2 and can immediately inspect the inspected object 1 after processing. Next, the inspection device 56 of this embodiment will be described by taking the case where it is assembled to the processing device 2 as an example, but the inspection device 56 is not limited to this.

[0056] Figure 5 This is a perspective view schematically showing an inspection device 56. The inspection device 56 includes a base 60 that supports the various components of the inspection device 56. An opening 62 extending along the X-axis is formed in the base 60. The inspection device 56 includes an inspection object holding mechanism 58, which is arranged to span the opening 62 of the base 60 and is capable of holding the inspection object 1; and an imaging mechanism 82, which is capable of imaging the inspection object 1 held by the inspection object holding mechanism 58.

[0057] The inspection device 56 includes an X-axis moving unit 64a that can move the inspection object holding mechanism 58 and the imaging mechanism 82 relative to each other along the X-axis direction; and a Y-axis moving unit 64b that can move the inspection object holding mechanism 58 and the imaging mechanism 82 relative to each other along the Y-axis direction. Figure 6 (A) schematically shows a perspective view of the X-axis moving unit 64a of the inspection device 56 and the inspection object holding mechanism 58. Figure 6 (B) schematically shows a perspective view of the imaging mechanism 82.

[0058] The X-axis moving unit 64a includes a guide rail 66a extending in the X-axis direction on the side of the opening 62 on the upper surface of the base 60. Furthermore, a guide rail 66b extending parallel to the guide rail 66a is included on the side of the opening 62 on the upper surface of the base 60, on the side opposite to the guide rail 66a. A moving body 68a is slidably mounted on the guide rail 66a, and a moving body 68b is slidably mounted on the guide rail 66b.

[0059] A bridge-shaped support structure 74 is provided on the movable body 68a and the movable body 68b so as to span the two movable bodies 68a and 68b. In addition, a nut portion (not shown) is provided at the lower end of one of the movable body 68a and the movable body 68b, and a ball screw 70 is screwed into the nut portion in parallel with the guide rails 66a and 66b.

[0060] A pulse motor 72 is connected to one end of the ball screw 70. When the pulse motor 72 rotates the ball screw 70, the movable bodies 68a and 68b move in the X-axis direction along the guide rails 66a and 66b, and the bridge-shaped support structure 74 moves in the X-axis direction. The inspection object holding mechanism 58 is supported by the support structure 74 at a position overlapping with the opening 62 of the base 60. The X-axis moving unit 64a moves the support structure 74 in the X-axis direction, thereby enabling the inspection object holding mechanism 58 to move in the X-axis direction.

[0061] The object holding mechanism 58 includes a loading portion 76 having a transparent body with upper and lower portions exposed. The transparent body is formed of a material such as glass or resin. The upper surface of the transparent body serves as a loading surface 76a on which the object 1 is loaded via the belt 7. The object holding mechanism 58 is capable of supporting the object 1 loaded on the loading surface 76a.

[0062] Figure 7 (A) is a top view schematically showing the inspection object holding mechanism 58, Figure 7 (B) is a cross-sectional view schematically showing the inspection object holding mechanism 58. The transparent body is also exposed on the back side opposite to the placement surface 76a, so that the inspection object 1 placed on the placement surface 76a can be observed from the lower surface side.

[0063] The inspection object holding mechanism 58 includes a belt holding portion 78 having a belt suction holding surface 78b on the outer peripheral side of the carrier portion 76. The belt holding portion 78 includes a suction groove 78a formed on the belt suction holding surface 78b. A suction source (not shown) is connected to the suction groove 78a via a suction path (not shown). The inspection object holding mechanism 58 also includes an annular frame support portion 80, which is arranged around the belt holding portion 78 and can support the frame 9 of the frame unit 11.

[0064] The frame unit 11 is placed on the inspection object holding mechanism 58 so that the frame support portion 80 overlaps the frame 9. When the suction source is activated, the inspection object 1 is suctioned and held by the inspection object holding mechanism 58 via the belt 7. At this time, suction is applied between the inspection object holding mechanism 58 and the belt 7, causing the belt 7 to adhere tightly to the entire mounting surface 76a. Therefore, the inspection object 1 held by the inspection object holding mechanism 58 does not shift during inspection.

[0065] For example, even in the case where the object to be inspected 1 is a wafer having warpage, the belt 7 is in close contact with the entire loading surface 76a when the object to be inspected 1 is held by the object holding mechanism 58. Therefore, the object to be inspected 1 is attracted and held by the object holding mechanism 58 in a state in which the warpage is alleviated. When the warpage of the object to be inspected 1 held by the object holding mechanism 58 is alleviated, the focus of the photographing unit is not easily deviated from the object to be inspected 1 when photographing each area of ​​the object to be inspected 1 one by one, so that the object to be inspected 1 can be photographed more clearly. In particular, in the structure of the present application, when an infrared camera is arranged on the back side and photographing is performed with the focus positioned on the front side, it is effective to alleviate the warpage of the object to be inspected 1.

[0066] Here, the height of the placing surface 76a of the placing portion 76 may be lower than the height of the tape suction holding surface 78b of the tape holding portion 78. Figure 7 As shown in (A), the suction groove 78a formed on the belt suction and holding surface 78b can reach the placement portion 76. In this case, when the frame unit 11 is placed on the inspection object holding mechanism 58, a gap is formed between the belt 7 and the placement surface 76a. When the suction source connected to the suction groove 78a is activated, the area of ​​the belt 7 that overlaps the inspection object 1 is quickly suctioned through this gap.

[0067] Specifically, it is considered that the height of the placing surface 76 a of the placing portion 76 is lower than the height of the tape suction and holding surface 78 b of the tape holding portion 78 by about 1 mm.

[0068] exist Figure 8 Schematically shows a cross-sectional view of the frame unit 11 and the object holding mechanism 58 when the object 1 is sucked and held by the object holding mechanism 58. Figure 8 As shown, when the suction source is activated, the gap between the belt 7 and the placement surface 76a is exhausted, so that the belt 7 and the placement surface 76a are in close contact with each other.

[0069] Alternatively, for example, the placement surface 76a may be coated with fluororesin to facilitate peeling of the tape 7 from the placement surface 76a when the suction source is stopped and the frame unit 11 is removed from the object holding mechanism 58 after inspection of the object 1 is completed.

[0070] Next, the photographing mechanism 82 will be described. Figure 5 As shown, the imaging mechanism 82 is supported by, for example, a gate-shaped support structure 84 provided on the base 60 so as to span the opening 62, the X-axis moving unit 64a, and the inspection object holding mechanism 58. A Y-axis moving unit 64b is provided on the support structure 84 for moving the imaging mechanism 82 along the Y-axis direction.

[0071] The Y-axis moving unit 64b has a pair of guide rails 86 arranged along the Y-axis direction on the upper surface of the support structure 84. A movable body 88 that supports the imaging mechanism 82 is slidably mounted on the pair of guide rails 86. A nut portion (not shown) is provided on the lower surface of the movable body 88, and a ball screw 90 parallel to the pair of guide rails 86 is screwed into the nut portion.

[0072] A pulse motor 92 is connected to one end of the ball screw 90. When the pulse motor 92 rotates the ball screw 90, the movable body 88 moves in the Y-axis direction along the guide rail 86, and the imaging mechanism 82 moves in the Y-axis direction. The X-axis moving unit 64a and the Y-axis moving unit 64b cooperate to function as a moving unit capable of relatively moving the inspection object holding mechanism 58 and the imaging mechanism 82 in a direction parallel to the mounting surface 76a.

[0073] The imaging mechanism 82 includes a first imaging unit 106a disposed above the placement portion 76 of the inspection object holding mechanism 58 and a second imaging unit 106b disposed below the placement portion 76. Figure 6 As shown in FIG. 8 (B), the imaging mechanism 82 further includes a coupling portion 108 that couples the first imaging unit 106a and the second imaging unit 106b.

[0074] The first imaging unit 106a is supported by a columnar support structure 94a. A lifting mechanism 96a is provided on the front surface of the columnar support structure 94a to raise and lower the first imaging unit 106a. The lifting mechanism 96a comprises a pair of guide rails 98a extending along the Z-axis; a movable body 100a slidably mounted on the guide rails 98a; and a ball screw 102a threadedly engaged with a nut provided on the rear surface of the movable body 100a.

[0075] A first imaging unit 106a is fixed to the front surface of the movable body 100a. Furthermore, a pulse motor 104a is connected to one end of the ball screw 102a. When the pulse motor 104a rotates the ball screw 102a, the movable body 100a moves in the Z-axis direction along the guide rail 98a, causing the first imaging unit 106a fixed to the movable body 100a to rise and fall.

[0076] The upper end of the connecting portion 108 is connected to, for example, the lower end of the rear side of the support structure 94a, and the lower end of the connecting portion 108 is connected to the upper end of the rear side of the columnar support structure 94b that supports the second imaging unit 106b. A lifting mechanism 96b having the same structure as the lifting mechanism 96a provided on the support structure 94a is provided on the front surface of the support structure 94b.

[0077] The lifting mechanism 96b comprises a pair of guide rails 98b extending along the Z-axis; a movable body 100b slidably mounted on the guide rails 98b; and a ball screw 102b threadedly engaged with a nut provided on the rear surface of the movable body 100b. A pulse motor 104b is connected to one end of the ball screw 102b. When the pulse motor 104b rotates the ball screw 102b, the second imaging unit 106b, fixed to the front surface of the movable body 100b, is raised or lowered.

[0078] The first imaging unit 106a faces downward and can capture an image of the inspection object 1 placed on the upper surface of the inspection object holding mechanism 58 from above. Furthermore, the second imaging unit 106b faces upward and can capture an image of the inspection object 1 from below via the transparent placement portion 76 and the belt 7. The first imaging unit 106a and the second imaging unit 106b are, for example, area cameras, linear cameras, 3D cameras, or infrared cameras.

[0079] Furthermore, in the imaging mechanism 82, the first imaging unit 106a and the second imaging unit 106b are connected to each other by a connecting portion 108 so that the first imaging unit 106a and the second imaging unit 106b are approximately aligned in a direction parallel to the placement surface 76a. This allows imaging of the same location on both the upper and lower surfaces of the inspection object 1. Furthermore, the connecting portion 108 is shaped so as not to interfere with the inspection object holding mechanism 58, even when any portion of the inspection object 1 is used as the imaging location.

[0080] Next, an embodiment of imaging and inspection by the imaging unit will be described.

[0081] exist Figure 8 In the figure, the front side of the inspection object 1 located on the upper side is photographed by the first photographing unit 106a composed of a visible light camera.

[0082] The front surface of the inspection object 1 is exposed, and a clear image is captured by the first imaging unit 106a composed of a visible light camera. Based on the captured image, chipping and cracks generated on the front surface of the inspection object 1 can be automatically identified.

[0083] On the other hand, the back surface of the inspection object 1 located on the lower side and attached to the tape 7 is imaged by the second imaging unit 106b composed of an infrared camera.

[0084] Figure 9This is a schematic diagram of second imaging unit 106b, which is comprised of an infrared camera. This second imaging unit 106b includes an objective lens unit 201 with adjustable focal length and an infrared CCD 202. A light source 203 can be integrated with or separate from the objective lens unit 201. The specific structure of second imaging unit 106b is not particularly limited.

[0085] Figure 10 This is a schematic diagram of an inspection object 1 viewed from the side, with devices 5 attached to a tape 7 arranged on the upper surface of a transparent placement portion 76 of an inspection object holding mechanism 58. The diagram shows processing marks 3a formed between the devices 5 and chipping 5c ​​occurring on the back surfaces 5b of the devices 5.

[0086] When the second imaging unit 106b focuses on the front surface 5a of the device 5 and captures the image, the infrared light R1 from the chipped edge 5c does not reach the front surface 5a (patterned surface) due to the fracture or other factors. This reduces the amount of reflection from the front surface 5a. This results in a region with lower brightness than other regions in the captured image (appearing dark).

[0087] On the other hand, since the infrared light R2 at the portion where the chipping 5 c does not exist reaches the front surface 5 a , a region having a higher brightness than the portion where the chipping 5 c exists is defined in the captured image.

[0088] Figure 11 (A) is an example of a captured image showing a situation where a chipping edge 5c extending in the X direction is generated in a region M1 on the back side 5b of the device 5. In the portion corresponding to the region M1, as shown in FIG. Figure 11 As shown in (B), chipping 5c ​​occurs in the lateral direction on the back side. In addition, the chipping 5c ​​region is divided into a region having a brightness different from that of other parts of the device 5 or the processing mark 3a in the captured image.

[0089] More specifically, the captured image region M1 is segmented into areas that are brighter than the machining mark 3a and darker than the device's back surface 5b. Furthermore, areas with brightness within a predetermined range can be detected as areas where chipping 5c ​​has occurred. Furthermore, the number of pixels in this area can be used to easily measure the size of the chipping 5c.

[0090] Similarly, in another region M2, a semicircular chipping 5c ​​is generated, thereby demarcating an area with a brightness different from that of other parts of the device 5 or the processing mark 3a. Furthermore, an area with a brightness within a predetermined range can be detected as an area where chipping has occurred, and the size of the chipping 5c ​​can be easily measured based on the number of pixels in that area.

[0091] Similarly, in another area M3, a linear crack (crack) 5d is generated, thereby forming a linear line with low brightness in the area of ​​the device 5. Moreover, by having a line with a brightness within a predetermined range, the line can be detected as an area where a crack (crack) 5d has occurred. In addition, the size of the crack (crack) 5d can be easily measured based on the number of pixels of the line. In addition, in the case of a linear crack (crack) 5d, a line with low brightness is formed. Figure 10 The fracture interface shown is the same interface and can therefore be displayed as a linear line on the image.

[0092] Next, each step performed in a method for processing a workpiece and a method for inspecting an object to be inspected using the above-described apparatus configuration will be described.

[0093] <Paste steps>

[0094] In this step, the back side of the workpiece is attached to the tape so that the front side of the workpiece is exposed.

[0095] Figure 1 An example is shown in which a wafer (inspection target 1 ) as a workpiece is attached to the tape 7 so that the front surface 1 a is exposed.

[0096] The workpiece is, for example, a semiconductor wafer, but a wafer on which no pattern is formed is also conceivable.

[0097] The lamination can be performed not only by adhesion using a paste layer but also by pressure bonding, thermocompression bonding, etc. of a tape having no paste layer but only a base material.

[0098] <Segmentation Step>

[0099] This step separates the workpiece to which the tape is attached.

[0100] Splitting refers to splitting into areas along predetermined splitting lines called intervals. In addition to tool cutting in which a tool is used to cut a workpiece, the following processing can also be used: laser cutting in which a workpiece is split by irradiating a laser beam with a wavelength that is absorbent to the workpiece; SD processing (STEALTH DICING: registered trademark, stealth cutting) in which a modified layer is formed by a laser beam with a wavelength that is transparent to the workpiece using band expansion; DBG (Dicing Before Grinding) processing in which a half-cut groove is formed on the front surface of the workpiece along the predetermined splitting line using a tool and then the workpiece is split by back grinding; SDBG (Stealth Dicing Before Grinding) processing in which the back surface of the workpiece is ground after the SD processing is performed.

[0101] Figure 2The state of a wafer (inspection object 1) divided by blade dicing is shown.

[0102] <Photography Steps>

[0103] In this imaging step, the workpiece is imaged from the back side of the workpiece via the tape using an infrared camera to form an image.

[0104] like Figure 7 and Figure 10 As shown in FIG. 1 , the second imaging unit 106b constituting the infrared camera is used to perform imaging from the back side 5b of the workpiece. Figure 10 As shown, by utilizing the difference in transmittance of infrared light R1 and R2 between the chipped portion 5 c and other portions, the brightness of the two portions can be made different in the captured image.

[0105] In addition, in this imaging step, the front side of the workpiece can be simultaneously imaged by the first imaging unit 106 a composed of a visible light camera.

[0106] <Detection Steps>

[0107] The detecting step detects chipping or cracks generated on the back surface based on the captured image formed by the capturing step.

[0108] like Figure 11 As shown in (A), an image showing the back surface 5b of device 5 is segmented into areas with varying brightness. The image is then multi-valued, and using the edges detected by edge detection as a reference, areas with brightness within a specified range are detected as areas where cracks or chipping have occurred. Furthermore, the size of the cracks or chipping is measured based on the number of pixels in these areas.

[0109] The present invention can be implemented as described above.

[0110] That is, the present invention is a method for confirming a workpiece, such as Figure 10 and Figure 11 As shown in (A), the back side 5b of the workpiece which has been divided and fixed to the belt 7 and the front side 5a is exposed is confirmed, wherein,

[0111] The workpiece confirmation method has the following steps:

[0112] a photographing step of photographing the workpiece from the back side 5b through the belt 7 using an infrared camera (second photographing unit 106b) to form a photographed image; and

[0113] The detecting step detects the chipping 5c ​​and / or the crack 5d generated on the rear surface 5n based on the captured image formed in the capturing step.

[0114] Thus, the back side of the workpiece can be confirmed based on the image captured by the infrared camera from the back side through the belt, which can reduce working hours and achieve time reduction. In addition, by using the infrared camera, chipping or cracks on the back side can be reliably detected, which can improve the reliability of the inspection.

[0115] In addition, if Figure 10 and Figure 11 As shown in (A), in the imaging step, imaging is performed with the infrared camera (second imaging unit 106b) focusing on the front surface of the workpiece.

[0116] This makes it possible to make defective portions such as chipping and cracks appear darker (lower the brightness) on the captured image, thereby enabling detection of chipping and cracks or measurement of their sizes.

[0117] In addition, the present invention is a method for processing a workpiece, wherein:

[0118] The processing method of the workpiece has the following steps:

[0119] a pasting step of pasting the back side of the workpiece to the tape so that the front side of the workpiece is exposed;

[0120] a segmentation step for segmenting the workpiece to which the tape is attached;

[0121] a photographing step of photographing the workpiece from the back side of the workpiece through the belt using an infrared camera to form a photographed image; and

[0122] The detecting step detects chipping and / or cracks generated on the back surface based on the captured image formed by the capturing step.

[0123] This allows a series of steps from the division of the workpiece to the detection of chipping and / or cracks on the back surface to be performed in a short time. Furthermore, the detection accuracy is high, thereby improving the reliability of the inspection.

Claims

1. A method for confirming a workpiece, wherein the back surface of a divided workpiece is confirmed, the back surface of the workpiece being fixed to a belt and the front surface being exposed, wherein: The workpiece confirmation method has the following steps: a photographing step of photographing the workpiece from the back side through the belt using an infrared camera to form a photographed image; and a detection step of detecting chipping and / or cracks generated on the back surface based on the captured image formed by the capturing step, In the imaging step, imaging is performed with the infrared camera focusing on the front surface of the workpiece.

2. A method for processing a workpiece, wherein: The processing method of the workpiece has the following steps: a step of attaching the back side of the workpiece to the tape so that the front side of the workpiece is exposed; a segmentation step of segmenting the workpiece to which the tape is attached; a photographing step of photographing the workpiece from the back side of the workpiece through the belt using an infrared camera to form a photographed image; as well as a detection step of detecting chipping and / or cracks generated on the back surface based on the captured image formed by the capturing step, In the imaging step, imaging is performed with the infrared camera focusing on the front surface of the workpiece.

Images