Inspection equipment

Abstract

To provide an inspection device capable of easily determining whether or not a tape is adhered at a uniform tension to a frame.SOLUTION: An inspection device for inspecting a tension of a tape adhered to a frame having an open part for housing a wafer at a center, contains: a frame support part that supports the frame to which the tape is adhered; a light source that irradiates a light toward the tape; an imaging camera that catches the light irradiated from the light source via the tape; a first polarizer that is distributed between the tape and the light source; and a second polarizer that is distributed between the tape and the imaging camera, and is positioned so as to seal the straight polarization light obtained by transmitting the first polarizer. By irradiating the straight polarization light transmitted from the first polarizer to the tape, the light transmits the second polarizer even in the case where deviation occurs in a polarization surface of the light, and the imaging camera performs an imaging.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an inspection apparatus for inspecting the tension of a tape adhered to a frame having an opening for accommodating a wafer at the center.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are formed on the surface and partitioned by a dicing line is accommodated in the opening of an annular frame having an opening formed at the center, and is integrally formed by a tape. It is divided into individual device chips by a dicing device or a laser processing device and used in electric devices such as mobile phones and personal computers (see, for example, Patent Document 1).

[0003] Further, since the wafer is supported by the frame via the tape, even if it is divided into individual device chips, it is transported to the next process, for example, the pickup process, while maintaining the form of the wafer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when attaching tape to the frame described above to support the wafer, a tape application machine (not shown in the illustration) is used to apply the tape to the opening in the frame. However, due to malfunctions of the tape application machine or problems with the tape itself, the tape may not be attached to the frame with uniform tension, and may be attached in a twisted state. If the wafer is supported in this state with the tape not attached to the frame with uniform tension, then when the wafer is divided into individual device chips, various problems may occur, such as misalignment of the device chips, devices falling off, the tape peeling off the frame, and even failure to properly pick up the device chips during the pickup process. Therefore, if the tape is not attached to the frame with uniform tension, it is necessary to exclude it. However, it is difficult for an operator to accurately and quickly determine whether the tape is attached to the frame with uneven tension by visual inspection, and countermeasures are needed for this purpose.

[0006] The present invention has been made in view of the above facts, and its main technical problem is to provide an inspection device that can easily determine whether or not tape is attached to a frame with uniform tension. [Means for solving the problem]

[0007] To solve the main technical problems described above, the present invention provides an inspection device for inspecting the tension of a tape attached to a frame having an opening in the center for housing a wafer, comprising: a frame support portion for supporting the frame to which the tape is attached; a light source for irradiating light toward the tape; an imaging camera for capturing the light irradiated from the light source through the tape; a first polarizing plate disposed between the tape and the light source; and a second polarizing plate disposed between the tape and the imaging camera and positioned to shield linearly polarized light that has passed through the first polarizing plate, wherein when linearly polarized light that has passed through the first polarizing plate is irradiated onto the tape, causing distortion in the polarization plane of the light, the imaging camera captures the light by passing it through the second polarizing plate.

[0008] The light source is preferably a white light source or a single-wavelength light source. [Effects of the Invention]

[0009] The inspection apparatus of the present invention is an inspection apparatus for inspecting the tension of a tape attached to a frame having an opening in the center for housing a wafer, and includes a frame support part that supports the frame to which the tape is attached, a light source that irradiates light toward the tape, an imaging camera that captures the light irradiated from the light source through the tape, a first polarizing plate disposed between the tape and the light source, and a second polarizing plate disposed between the tape and the imaging camera and positioned to block linearly polarized light that has passed through the first polarizing plate, so that when linearly polarized light that has passed through the first polarizing plate is irradiated onto the tape, distortion occurs in the polarization plane of the light, the imaging camera captures the image by passing through the second polarizing plate, thereby eliminating problems such as the tape being attached to the frame with uneven tension, the wafer supported by the tape being divided into individual device chips, causing the device chips to be misaligned, the devices to fall off, the tape peeling off the frame, and furthermore, the inability to properly pick up the device chips in the pickup process. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall perspective view of the inspection device. [Figure 2] Figure 1 is a perspective view showing the optical systems of the light irradiation unit and imaging unit installed in the inspection apparatus shown. [Figure 3] (a) A plan view showing the case where tape is applied to the frame with uniform tension, and (b) A plan view showing the case where tape is applied to the frame with uneven tension. [Figure 4] (a) A plan view showing the case where the wafer is attached to the center of the tape and the tape is attached to the frame with uniform tension, and (b) A plan view showing the case where the wafer is attached to the center of the tape and the tape is attached to the frame with uneven tension. [Figure 5] This is a perspective view showing another embodiment of the inspection device. [Figure 6] Figure 5 is a perspective view showing the optical systems of the light irradiation unit and imaging unit of the inspection apparatus shown. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the inspection apparatus configured according to the present invention will be described in detail with reference to the attached drawings.

[0012] Figure 1 shows an overall perspective view of the inspection apparatus 1 of this embodiment. The inspection apparatus 1 is a device for inspecting the tension of a tape T attached to an annular frame F having an opening Fa in the center for housing a wafer, as shown in the figure. The inspection apparatus 1 includes a frame support section 24 that supports the frame F to which the tape T is attached, a light irradiation means 40, and an imaging means 50 that captures the light irradiated from the light irradiation means 40 via the tape T attached to the frame F supported by the frame support section 24.

[0013] The frame support portion 24 described above is disposed on the support means 20 shown in Figure 1. As shown in Figure 1, the support means 20 includes a rectangular X-axis movable plate 21 mounted on a base 2 so as to be movable in the X-axis direction, a rectangular Y-axis movable plate 22 mounted on the X-axis movable plate 21 so as to be movable in the Y-axis direction, and a cylindrical support column 23 fixed to the upper surface of the Y-axis movable plate 22. An annular frame support portion 24 is formed at the upper end of the support column 23. The frame support portion 24 has an XY plane defined by the X-axis and Y-axis as its holding surface, and the holding surface is open in the center. In this embodiment, a light irradiation means 40 is disposed within the support column 23 on which the frame support portion 24 is formed.

[0014] The inspection device 1 is equipped with a moving means 30 for moving the frame support portion 24 in the X-axis direction and the Y-axis direction. The moving means 30 includes an X-axis moving means 33 for moving the frame support portion 24 in the X-axis direction and a Y-axis moving means 36 for moving the frame support portion 24 in the Y-axis direction. The X-axis moving means 33 converts the rotational motion of the motor 31 into linear motion via a ball screw 32 and transmits it to the X-axis movable plate 21, moving the X-axis movable plate 21 in the X-axis direction along a pair of guide rails 2a, 2a arranged on the base 2 along the X-axis direction. The Y-axis moving means 36 converts the rotational motion of the motor 34 into linear motion via a ball screw 35 and transmits it to the Y-axis movable plate 22, moving the Y-axis movable plate 22 in the Y-axis direction along a pair of guide rails 21a, 21a arranged on the X-axis movable plate 21 along the Y-axis direction.

[0015] A frame 3 is erected on the base 2 to the side of the moving means 30, consisting of a vertical wall portion 3a and a horizontal wall portion 3b extending horizontally from the upper end of the vertical wall portion 3a. The imaging means 50 described above is positioned downward at the tip of the horizontal wall portion 3b. A display means 4 is provided on the upper surface of the horizontal wall portion 3b.

[0016] The light irradiation means 40 of this embodiment includes a light irradiation unit 41 shown in Figure 2. The light irradiation unit 41 includes a light source 42 that irradiates light L0 toward a tape T supported by a frame F supported by a frame support portion 24, and a first polarizing plate 44 disposed between the light source 42 and the tape T. The imaging means 50 described above also includes an imaging unit 51 shown in Figure 2. The imaging unit 51 includes an imaging camera 52 that captures light L0 irradiated from the light source 42 through the tape T, and a second polarizing plate 54 disposed between the imaging camera 52 and the tape T.

[0017] The first polarizing plate 44 is a polarizing plate that transmits only the light polarized in a predetermined direction among the light L0 irradiated from the light source 42. In the present embodiment, it is arranged so as to transmit only the light polarized in the X-axis direction in the drawing (linear polarized light L1). The linear polarized light L1 is irradiated onto the tape T adhered to the frame F supported by the frame support portion 24, and the transmitted light L2 that has passed through the tape T is irradiated onto the second polarizing plate 54. The second polarizing plate 54 is rotated 90 degrees in the polarization direction with respect to the first polarizing plate 44 so as to transmit only the light polarized in the Y-axis direction in the drawing. Although not shown in the figure, shielding means is provided so that the light L0 irradiated from the light source 42 does not reach the imaging camera 52 through the outside of the frame F, and light other than the light L0 of the light source 42 does not enter the imaging camera 52. Further, the light source 42 of the light irradiation unit 40 may be, for example, a white light source including a wide-band wavelength or a single-wavelength light source such as an LED.

[0018] The above-described display means 4, imaging means 50, and moving means 30 are connected to a control means 100 constituted by a computer. In the illustrated embodiment, the control means 100 is shown outside the inspection device 1 for convenience of explanation, but actually it is disposed inside the inspection device 1. The image captured by the imaging camera 52 is sent to the control means 100 and displayed on the display means 4 connected to the control means 100. The inspection device 1 of the present embodiment generally has the configuration as described above, and the functions and operations of the inspection device 1 will be described below.

[0019] As shown in FIG. 2, the above-described inspection device 1 can use as an inspection object an object in which a tape T having an adhesive layer is adhered to a frame F having an opening Fa for accommodating a wafer in the center and integrated, or an object in which a wafer W as a workpiece is adhered to the center of the opening Fa where the tape T is adhered to the frame F and integrated. In the following description, the case of inspecting as a workpiece an object in which a tape T is adhered to a frame F having an opening Fa for accommodating a wafer and integrated and no wafer is adhered will be described.

[0020] If the above-described test object is prepared, it is conveyed to the above-described inspection apparatus 1 and placed on the frame support portion 24. Although not particularly specified in the present embodiment, fixing means for sucking or gripping the frame F may be provided to fix the frame F to the frame support portion 24.

[0021] If the frame F is placed on the frame support portion 24, the X-axis moving means 33 and the Y-axis moving means 36 are operated to position the opening Fa of the frame F at the inspection position directly below the imaging unit 50. Next, the light source 42 of the light irradiation unit 40 described based on FIG. 2 is operated to irradiate the light L0 toward the first polarizing plate 44. As described above, the first polarizing plate 44 is a polarizing plate that transmits only the linearly polarized light L1 polarized in the X-axis direction in the drawing among the light L0 irradiated from the light source 42, and the linearly polarized light L1 transmitted through the first polarizing plate 44 is irradiated to the tape T exposed in the opening Fa of the frame F.

[0022] Here, if the tape T is adhered to the frame F with a uniform tension, the linearly polarized light L1 irradiated to the tape T is transmitted without the polarization plane being distorted and becomes transmitted light L2. This transmitted light L2 travels while the polarization plane of the linearly polarized light L1 is maintained in the X-axis direction and is irradiated to the second polarizing plate 54. As described above, since the second polarizing plate 54 is disposed in a state where the polarization direction is rotated 90 degrees with respect to the first polarizing plate 44, the transmitted light L2 cannot pass through the second polarizing plate 54 and is blocked by the second polarizing plate 54. FIG. 3(a) shows an image of the imaging camera 52 that has imaged the region Ta of the tape T exposed in the opening Fa of the frame F in this state. In this state, since the transmitted light L2 cannot be captured by the imaging camera 52, the display means 4 displays a state where no light is captured at all in the region Ta of the tape T (black state). That is, when the image shown in FIG. 3(a) is displayed by the inspection apparatus 1, as a result of the inspection, it is found that the tape T is adhered to the frame F with a uniform tension.

[0023] On the other hand, the case where the above inspection is performed when the tape T is attached to the frame F with uneven tension will be described. When the tape T is attached to the frame F with uneven tension, linearly polarized light L1 incident on the tape T from below via the first polarizing plate 44 becomes transmitted light L2, which consists of light whose polarization plane is distorted by passing through the twisted region attached with uneven tension, and light whose polarization plane is maintained by passing through the region attached with uniform tension. When this transmitted light L2 is irradiated onto the second polarizing plate 54, of the transmitted light L2, the light whose polarization plane is maintained does not reach the imaging camera 52 because it cannot pass through the second polarizing plate 54, and only the light whose polarization plane is distorted passes through the second polarizing plate 54 to become the final transmitted light L3 and reaches the imaging camera 52, and as shown in Figure 3(b), the presence of the tension-uneven region S is detected by the imaging camera 52 and displayed on the display means 4. In other words, if the inspection device 1 displays an image like the one shown in Figure 3(b), the inspection results indicate that the tape T is attached to the frame F with uneven tension.

[0024] According to the inspection apparatus 1 of the above embodiment, when the tape T is attached to the frame F with uneven tension, the imaging camera 52 of the inspection apparatus 1 can easily capture the state of uneven tension, thus eliminating problems such as the wafer supported by the tape T being separated into individual device chips, causing the device chips to be misaligned, devices to fall off, the tape peeling off the frame, and even the inability to properly pick up the device chips during the pickup process.

[0025] The present invention is not limited to the embodiments described above. The object to be inspected can also be a frame F with tape T attached and a wafer W, which is the workpiece, attached to the center of the opening Fa, as shown on the right side of Figure 2. Figure 4(a) shows an image displayed on the display means 4 after inspecting an object to be inspected, in which tape T is attached to the frame F with uniform tension and wafer W is supported in the center of the opening Fa, using the inspection device 1 described above in accordance with the procedure described above. As can be seen from Figure 4(a), except for the central region Wa to which wafer W is attached, linearly polarized light L1 is irradiated onto the region Ta where tape T is attached with uniform tension, and the transmitted light L2, whose polarization plane is maintained, does not pass through the second polarizing plate 54. Therefore, the imaging camera 52 cannot capture the transmitted light L2, and a state in which no light is captured is displayed. In other words, when the inspection device 1 displays the image shown in Figure 4(a), it is determined as a result of the inspection that tape T is attached to the frame F with uniform tension. In Figure 4(a), the central region Wa of region Ta is displayed as black regardless of the tension of the tape T attached to the frame F, because the linearly polarized light L1 that has passed through the first polarizing plate 44 is blocked by the wafer W.

[0026] Figure 4(b) shows an image displayed on the display means 4 after inspecting an object under inspection, in which tape T is attached to frame F with uneven tension and a wafer W is supported in the center, using the inspection device 1 described above. When tape T is attached to frame F with uneven tension, linearly polarized light L1 incident on tape T from below has its polarization plane distorted as it passes through the twisted region where it is attached with uneven tension. Of the transmitted light L2, which is composed of light with a distorted polarization plane and light that has passed through the region attached with uniform tension and whose polarization plane is maintained, the light with a distorted polarization plane passes through the second polarizing plate 54 to become the final transmitted light L3 and reaches the imaging camera 52, and as shown in Figure 4(b), an image including the tension-uneven region S is displayed on the display means 4. As a result, it is determined that tape T is attached to frame F with uneven tension as a result of the inspection, and the same effects as in the embodiment described earlier can be obtained.

[0027] In the embodiments described above, as a specific form of capturing light emitted from the light source of the present invention with an imaging camera via tape, an example was shown in which a light irradiation unit 41 including a light source 42 and a second polarizing plate 44, and an imaging unit 50 including an imaging camera 52 and a second polarizing plate 54 are arranged so as to sandwich the tape T, which is the object to be inspected, from above and below. However, the present invention is not limited to the above-described embodiments. Another embodiment of capturing light emitted from a light source with an imaging camera via tape will be described based on Figures 5 and 6.

[0028] Figure 5 shows a part of inspection apparatus 1', which is another embodiment of the present invention. Inspection apparatus 1' has generally the same configuration as inspection apparatus 1 shown in Figure 1, and the same configuration as inspection apparatus 1 shown in Figure 1 is omitted from the illustration.

[0029] In the inspection device 1', a light irradiation means 40' and an imaging means 50' are provided instead of the light irradiation means 40 and imaging means 50 of the inspection device 1 described above. As shown in Figure 5, the light irradiation means 40' and the imaging means 50' are provided at the tip of the horizontal wall portion 3b of the frame 3. The irradiation means 40' includes a light irradiation unit 41' shown in Figure 6(a), and the light irradiation unit 41' comprises a light source 42' and a first polarizing plate 44'. The light source 42' is a light source equivalent to the light source 42 described above, and irradiates light L0 towards a tape T attached to a frame F placed on a frame support portion 24 (not shown) at a predetermined incident angle. The first polarizing plate 44' is positioned between the light source 42' and the tape T, and as can be seen from Figure 6(b), which is a plan view of a portion of Figure 6(a) viewed from above, it is a polarizing plate that transmits only light polarized in a predetermined direction, for example, in the Y-axis direction (linearly polarized light L1) from the light L0 irradiated from the light source 42'. The imaging means 50' includes the imaging unit 51' shown in Figure 6(a), which comprises an imaging camera 52' and a second polarizing plate 54'. The second polarizing plate 54' is positioned between the imaging camera 52' and the tape T, and as shown in Figure 6(b), it is a polarizing plate that transmits only light polarized in the X-axis direction. The imaging camera 52' and the second polarizing plate 54' constituting the imaging unit 51' are arranged in a direction of reflection angle corresponding to the incident angle of light irradiated from the light source 42' toward the tape T.

[0030] When performing an inspection using the inspection apparatus 1' shown in Figure 5, first, the object to be inspected is placed on a frame support 24 (not shown) and moved directly below the light irradiation means 40' and imaging means 50', as shown in Figure 6(a). Next, the light source 42' is activated to irradiate the first polarizing plate 44' with light L0. As described above, the first polarizing plate 44' is a polarizing plate that transmits only linearly polarized light L1 polarized in the Y-axis direction in the figure from the light source 42', and the linearly polarized light L1 transmitted through the first polarizing plate 44' is irradiated onto the tape T exposed at the opening Fa of the frame F at a predetermined angle of incidence.

[0031] Linearly polarized light L1 irradiated onto the tape T attached to the frame F is reflected on the tape T at a reflection angle corresponding to the predetermined incidence angle, and as reflected light L2, it is irradiated onto the second polarizer 54'. As described above, the polarization direction of the second polarizer 54' is rotated by 90 degrees so as to transmit only light polarized in the X-axis direction in the figure. Although not shown in the figure, appropriate shielding means are provided to prevent light L0 irradiated from the light source 42' from being reflected in the area outside the tape T and reaching the imaging camera 52', and to prevent light other than light L0 from the light source 42' from entering the imaging camera 52'.

[0032] Here, assuming that the tape T is attached to the frame F with uniform tension, the linearly polarized light L1 irradiated onto the tape T is reflected without distortion of its polarization plane, becoming reflected light L2. This reflected light L2 travels toward the imaging unit 51' with the polarization plane of the linearly polarized light L1 maintained in the Y-axis direction, and irradiates the second polarizing plate 54'. As described above, the second polarizing plate 54' is positioned with its polarization direction rotated by 90 degrees relative to the first polarizing plate 44'. As a result, if the polarization plane of the light that has been made linearly polarized L1 by the first polarizing plate 44' is reflected by the tape T without distortion, the reflected light L2 cannot pass through the second polarizing plate 54' and is shielded by the second polarizing plate 54'. In this state, the imaging camera 52' captures the region Ta of the tape T exposed at the opening Fa of the frame F, and by applying shape correction to make the region Ta circular, the image shown in Figure 3(a) can be obtained. In this embodiment, the linearly polarized light L1 reflected by the tape T does not pass through the second polarizing plate 54', so the reflected light L2 cannot be captured by the imaging camera 52', and the state in which no light is captured (black state) is displayed on the display means 4. That is, the inspection device 1' displays the image shown in Figure 3(a) on the display means 4, and as a result of the inspection, it is found that the tape T is attached to the frame F with uniform tension.

[0033] On the other hand, if the tape T is attached to the frame F of the object under inspection with uneven tension, the linearly polarized light L1 irradiated onto the tape T via the first polarizing plate 44' becomes reflected light L2, which consists of light whose polarization plane is distorted by being reflected in the twisted region where the tape T is attached with uneven tension, and light whose polarization plane is maintained by being reflected in the region where the tape T is attached with uniform tension. When this reflected light L2 is irradiated onto the second polarizing plate 54', the light whose polarization plane is maintained cannot be transmitted through the second polarizing plate 54' and therefore does not reach the imaging camera 52', while the light with a distorted polarization plane is transmitted through the second polarizing plate 54' and becomes the final reflected light L3, reaching the imaging camera 52'. Based on the light with a distorted polarization plane in this way, the presence of the tension-uneven region S is detected by the imaging camera 52', and an image like the one shown in Figure 3(b) is displayed on the display means 4, revealing that the tape T is attached to the frame F with uneven tension as a result of the inspection.

[0034] In the other embodiment described above, as in the embodiment described earlier, when the tape T is attached to the frame F with uneven tension, the state of uneven tension can be easily detected. This eliminates problems such as the wafer being divided into individual device chips, causing device chip misalignment, devices falling off, the tape peeling off the frame, and even the inability to properly pick up device chips during the pickup process. [Explanation of symbols]

[0035] 1, 1': Inspection device 2: Base 2a, 2a: Guide rail 3: Frame 3a: Vertical wall 3b:Horizontal wall part 4:Display means 20: Support means 21:X-axis movable plate 22: Y-axis movable plate 23: Post 24: Frame support section 30: Means of transportation 33:X-axis movement means 36: Y-axis movement means 40, 40': Light irradiation means 41, 41': Light irradiation unit 42, 42': Light source 44, 44': First polarizer 50, 50': Imaging means 51, 51': Imaging unit 52, 52': Imaging camera 54, 54': Second polarizer 100: Control means F: Frame Fa: Opening L0: light L1: Linear polarization L2: Transmitted or reflected light L3: Final transmitted light or final reflected light T: Tape W: Waha

Claims

1. An inspection device for inspecting the tension of a tape attached to a frame having an opening in the center for housing a wafer, The device includes a frame support that supports a frame to which tape is attached, a light source that irradiates light toward the tape, an imaging camera that captures the light irradiated from the light source through the tape, a first polarizing plate disposed between the tape and the light source, and a second polarizing plate disposed between the tape and the imaging camera and positioned to block linearly polarized light that has passed through the first polarizing plate. An inspection device in which linearly polarized light that has passed through the first polarizing plate is irradiated onto the tape, causing distortion in the polarization plane of the light, and the imaging camera captures the image as the light passes through the second polarizing plate.

2. The inspection apparatus according to claim 1, wherein the light source is a white light source or a single-wavelength light source.

Images