JP6845023B2 - Inspection equipment - Google Patents

Description

The present invention relates to an inspection device capable of easily detecting cracks generated in a device.

A wafer in which a plurality of devices such as ICs and LSIs are partitioned by a planned division line and formed on the surface of a silicon substrate is cut by a dicing device equipped with a rotatable cutting blade and a laser processing device that irradiates a laser beam. It is divided into individual devices, and the divided devices are used for electric devices such as mobile phones, personal computers, and televisions.

However, if the wafer is divided into individual devices by a dicing device or a laser processing device, or if half-cuts such as removing the patent film and Low-k film laminated on the planned division line are performed, fine cracks will occur inside the device. It may occur, and there is a problem that cracks are overlooked and the quality of the device is deteriorated (see Patent Documents 1 and 2).

Further, if cracks are generated inside the wafer before the wafer is processed by the dicing device or the laser processing device, there is a problem that the cracks are increased by the dicing processing and the laser processing of the wafer and the damage is increased.

Further, in a wafer in which a silicon wafer and a glass substrate are laminated and a wafer in which two or more layers of silicon wafers are laminated, there is a problem that it is difficult to detect cracks generated inside.

Japanese Unexamined Patent Publication No. 2003-334751 Japanese Unexamined Patent Publication No. 2004-188475

An object of the present invention made in view of the above facts is to provide an inspection device capable of easily detecting a crack generated in a device.

The following inspection devices are provided by the present invention in order to solve the above problems. That is, it is an inspection device and emits light having a wavelength that is transparent to the wafer from the table on which the wafer on which a plurality of devices are formed and the wafer arranged on the outer periphery of the table are placed. It is composed of at least a light source, an imaging means arranged facing the table to image a wafer, and a display means for displaying an image captured by the imaging means, and the light source is larger than the diameter of the wafer. an inspection apparatus that has a plurality of spaced top in the circumferential direction of the annular plate having an inner diameter.

Preferably, the image storage means for storing the image captured by the imaging means and the position storage means for storing the position of the defect are included. The substrate constituting the wafer is Si, and the wavelength transmitted through the wafer is preferably 1064 to 3000 nm.

The inspection device provided by the present invention irradiates a table on which a wafer on which a plurality of devices are formed is placed, and light having a wavelength that is transparent to the wafer from the outer periphery of the table and is arranged on the outer periphery of the table. Since it is composed of at least a light source, an imaging means that is arranged facing the table and images the wafer, and a display means that displays an image captured by the imaging means, the form of the wafer is maintained. Cracks generated in individual devices can be easily detected in the state, and minute cracks generated in the device can be detected by half-cutting such as removing the passivation film and Low-k film laminated on the planned division line. can do. Further, in the inspection apparatus of the present invention, it is possible to detect whether or not a crack is generated inside the wafer before processing the wafer by the dicing apparatus and the laser processing apparatus.

The perspective view of the inspection apparatus configured according to this invention. The perspective view which shows the light source of the inspection apparatus of this invention, and the wafer which is inspected by the inspection apparatus of this invention. The schematic diagram which shows the state which the inspection is performed by the inspection apparatus of this invention.

Hereinafter, embodiments of an inspection device configured according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the inspection device 2 includes a base 4, a holding means 6 for holding an object to be inspected such as a wafer, a moving means 8 for moving the holding means 6, and an inspected means held by the holding means 6. An imaging means 10 for capturing an object and a display means 12 for displaying an image captured by the imaging means 10 are provided, and as shown in FIG. 2, a lighting means 14 for illuminating the object to be inspected from the outer periphery of the object to be inspected is provided. ..

As shown in FIG. 1, the holding means 6 has a rectangular X-direction movable plate 16 mounted on the base 4 so as to be movable in the X direction, and a rectangle mounted on the X-direction movable plate 16 so as to be movable in the Y direction. It includes a Y-direction movable plate 18 having a shape, a cylindrical support plate 20 fixed to the upper surface of the Y-direction movable plate 18, and a rectangular cover plate 22 fixed to the upper end of the support column 20. An elongated hole 22a extending in the Y direction is formed in the cover plate 22, and a circular table 24 extending upward through the elongated hole 22a is rotatably mounted on the upper end of the support column 20. On the upper surface of the table 24, a circular suction chuck 26 formed of a porous material and extending substantially horizontally is arranged, and the suction chuck 26 is connected to a suction means (not shown) by a flow path. There is. Then, in the table 24, by generating a suction force on the upper surface of the suction chuck 26 by the suction means, the object to be inspected placed on the upper surface of the suction chuck 26 can be sucked and held. Further, a plurality of clamps 28 are arranged on the peripheral edge of the table 24 at intervals in the circumferential direction. The X direction is the direction indicated by the arrow X in FIG. 1, and the Y direction is the direction indicated by the arrow Y in FIG. 1 and is orthogonal to the X direction. The plane defined by the X and Y directions is substantially horizontal.

As shown in FIG. 1, the moving means 8 includes an X-direction moving means 30 that moves the table 24 in the X direction, a Y-direction moving means 32 that moves the table 24 in the Y direction, and a table centered on an axis extending in the vertical direction. Includes a rotating means (not shown) for rotating 24. The X-direction moving means 30 has a ball screw 34 extending in the X direction on the base 4, and a motor 36 connected to one end of the ball screw 34. The nut portion (not shown) of the ball screw 34 is fixed to the lower surface of the X-direction movable plate 16. Then, the X-direction moving means 30 converts the rotational motion of the motor 36 into a linear motion by the ball screw 34 and transmits it to the X-direction movable plate 16, and moves the X-direction movable plate 16 along the guide rail 4a on the base 4. It advances and retreats in the X direction, thereby advancing and retreating the table 24 in the X direction. The Y-direction moving means 32 has a ball screw 38 extending in the Y direction on the X-direction movable plate 16 and a motor 40 connected to one end of the ball screw 38. The nut portion (not shown) of the ball screw 38 is fixed to the lower surface of the Y-direction movable plate 18. Then, the Y-direction moving means 32 converts the rotational motion of the motor 40 into a linear motion by the ball screw 38 and transmits it to the Y-direction movable plate 18, and the Y-direction movable plate is transmitted along the guide rail 16a on the X-direction movable plate 16. The 18 is moved forward and backward in the Y direction, thereby moving the table 24 forward and backward in the Y direction. The rotating means has a motor (not shown) built in the support column 20, and rotates the table 24 with respect to the support column 20 about an axis extending in the vertical direction.

Continuing the description with reference to FIG. 1, the imaging means 10 is arranged on the lower surface of the tip of the frame body 42 extending upward from the upper surface of the base 4 and then extending substantially horizontally, and is located above the table 24. The image pickup means 10 includes a normal image pickup element (CCD) that images an object to be inspected with visible light, an optical system that captures infrared rays, and an image pickup element (infrared CCD) that outputs an electric signal corresponding to the infrared rays captured by the optical system. (Neither is shown). Further, a display means 12 that is electrically connected to the image pickup means 10 and outputs a signal of an image captured by the image pickup means 10 is mounted on the upper surface of the tip of the frame body 42.

The wafer 44 as an object to be inspected and the lighting means 14 of the inspection device 2 will be described with reference to FIG. The surface 44a of the disk-shaped wafer 44, which can be formed of Si (silicon) or the like, is divided into a plurality of rectangular regions by a grid-like division schedule line 46, and a device 48 is formed in each of the plurality of rectangular regions. .. In the illustrated embodiment, the back surface of the wafer 44 is attached to the adhesive tape 52 whose peripheral edge is fixed to the annular frame 50. The surface 44a of the wafer 44 may be attached to the adhesive tape 52. The lighting means 14 of the inspection device 2 includes an annular plate 54 having an inner diameter larger than the diameter of the wafer 44 and a plurality of illumination means 14 arranged on the upper surface of the annular plate 54 at intervals in the circumferential direction (four in the illustrated embodiment). ) Is included with the light source 56. It is convenient that the outer diameter of the annular plate 54 is smaller than the inner diameter of the annular frame 50. The light source 56 that irradiates light inward in the radial direction of the annular plate 54 irradiates light having a wavelength that is transparent to the object to be inspected. For example, when the substrate constituting the wafer 44 as the object to be inspected is Si (silicon), the light source 56 irradiates light having a wavelength of 1064 to 3000 nm having transparency to Si (silicon).

In the illustrated embodiment, as shown in FIG. 3, the control means 58 that controls the operation of the moving means 8, the imaging means 10, and the display means 12 is electrically connected to the moving means 8, the imaging means 10, and the display means 12. .. The control means 58 composed of a computer includes a central processing unit (CPU) 60 that performs arithmetic processing according to a control program, a read-only memory (ROM) 62 that stores a control program and the like, and a readable and writable random speed that stores an arithmetic result and the like. Includes access memory (RAM) 64. The inspection device 2 configured according to the present invention preferably includes an image storage means for storing the image captured by the image pickup means 10 and a position storage means for storing the position of a defect such as a crack in the object to be inspected. In the illustrated embodiment, the random access memory 64 has an image storage unit 64a that constitutes the image storage means and a position storage unit 64b that constitutes the position storage means.

When inspecting the wafer 44 using the inspection device 2, the wafer 44 attached to the adhesive tape 52 is pressed with the surface attached to the adhesive tape 52 (the back surface of the wafer 44 in the illustrated embodiment) facing downward. It is placed on the upper surface of the table 24. Alternatively, the wafer 44 is divided into individual devices 48 along the scheduled division line 46 by a dicing device having a rotatable cutting blade and a laser processing device irradiating a laser beam, and the shape of the wafer 44 is maintained by the adhesive tape 52. You may place the thing on the upper surface of the table 24. Alternatively, a dicing device or a laser processing device that has been half-cut such as removing the passivation film and the Low-k film laminated on the scheduled division line 46 may be placed on the upper surface of the table 24. Next, the suction means is operated to generate a suction force on the upper surface of the table 24, and the wafer 44 (the back surface side of the wafer 44 in the illustrated embodiment) is sucked on the upper surface of the table 24. Further, the outer peripheral edge portion of the annular frame 50 is fixed by a plurality of clamps 28. Next, as shown in FIG. 3, the lighting means 14 is arranged between the outer circumference of the wafer 44 and the inner circumference of the annular frame 50 (that is, the outer circumference of the table 24), and the outer circumference of the wafer 44 is provided by the light source 56 of the lighting means 14. Irradiates the wafer 44 with light having a wavelength that is transparent. Next, the table 24 is moved by the moving means 8 so that the imaging means 10 faces the wafer 44. Next, the entire wafer 44 is imaged by the imaging means 10 while the table 24 is appropriately moved by the moving means 8. In this way, the wafer 44 is imaged by the imaging means 10 arranged facing the wafer 44 while irradiating the wafer 44 with light having a wavelength that is transparent to the wafer 44 from the outer periphery of the wafer 44. It is possible to image the cracks existing in. Then, since the image captured by the imaging means 10 is displayed on the display means 12, a crack in the wafer 44 (an example of the crack is indicated by reference numeral 66 in FIG. 3) is detected based on the image displayed on the display means 12. can do. When a crack is detected, the image of the region including the crack is stored in the image storage unit 64a of the random access memory 64, and the position of the crack is stored in the position storage unit 64b of the random access memory 64.

As described above, in the inspection device 2, the wafer 44 is divided into individual devices 48 along the scheduled division line 46 by the dicing device and the laser processing device, and then the wafer 44 is generated in each device 48 while maintaining the shape of the wafer 44. The cracks can be easily detected, and the fine cracks generated in the device 48 can be detected by half-cutting such as removing the dicing film and the Low-k film laminated on the planned division line 46. Further, the inspection device 2 can also detect whether or not a crack is generated inside the wafer 44 before the wafer 44 is machined by the dicing device or the laser processing device.

In the inspection device 2, since the inspection can be performed before and after the processing applied to the wafer 44 by the dicing device or the laser processing device, it is possible to verify the influence of the processing applied to the wafer 44 on the elongation of cracks. When a crack in the wafer 44 is detected in the inspection before processing, the image of the area including the crack is stored in the image storage unit 64a of the random access memory 64, and the position of the crack is stored in the position storage unit 64b of the random access memory 64. Remember. Further, in the inspection after processing, the same region as the region (region including cracks) stored in the image storage unit 64a before processing is imaged, the image of the imaged region is stored in the image storage unit 64a, and the position of the crack is recorded. Is stored in the position storage unit 64b. Then, by comparing the image before processing and the image after processing, it is possible to verify the influence of the processing applied to the wafer 44 on the elongation of cracks.

After the wafer 44 is divided into individual devices 48, a sorting operation for sorting the device 48 without cracks and the device 48 having cracks is performed. During this sorting work, the position memory of the random access memory 64 is stored. By referring to the position of the crack stored in the unit 64b, it is not necessary to inspect the presence or absence of the crack for each device 48, so that the efficiency of the sorting operation is improved.

The inspection apparatus of the present invention may be configured by using the chuck table of the dicing apparatus or the laser processing apparatus and the imaging means for performing alignment as the table and the imaging means of the present invention. Further, in the illustrated embodiment, the example in which the light source is arranged on the annular plate 54 has been described, but the cover plate 22 of the holding means 6 is spaced outside the radial direction of the table 24 in the circumferential direction of the table 24. A plurality of light sources may be arranged in the.

2: Inspection device 10: Imaging means 12: Display means 24: Table 44: Wafer 48: Device 56: Light source 64: Random access memory (RAM)
64a: Image storage unit (image storage means)
64b: Position storage unit (position storage means)

Claims (3)

It ’s an inspection device,
A table on which a wafer on which a plurality of devices are formed is placed, a light source arranged on the outer periphery of the table and irradiating light having a wavelength transparent to the wafer from the outer periphery of the table, and facing the table. An imaging means for imaging a wafer, a display means for displaying an image captured by the imaging means, and a display means.
From, at least composed ,
The light source, the inspection apparatus that has a plurality of circumferentially spaced on the upper surface of the annular plate having an inner diameter larger than the diameter of the wafer. The inspection device according to claim 1, further comprising an image storage means for storing an image captured by the image pickup means and a position storage means for storing the position of a defect. The inspection device according to claim 1, wherein the substrate constituting the wafer is Si, and the wavelength transmitted through the wafer is 1064 to 3000 nm.