Device for inspecting defects on wafer subjected to cutting or arranging process

Abstract

To provide a device for inspecting defects on a wafer subjected to a cutting or arranging process.SOLUTION: A device for inspecting defects on a wafer subjected to a cutting or arranging process is applied to inspection of the wafer. The wafer includes a silicon wafer subjected to the cutting or arranging process, and a blue film attached to a bottom of the silicon wafer. The device for inspecting the defects on the wafer subjected to the cutting or arranging process includes an infiltrate detector, a lens group, an optical lens group, a light source, a visible light camera, and an infrared camera. The infiltrate detector has a housing and a transparent cap. The liquid is so arranged as to flow and fill between the blue film and the transparent cap. The lens group is disposed below the transparent cap and within the housing. The optical lens group is disposed in the housing and below the lens group. The light source is disposed within the housing and emits visible light and infrared light. An image of the bottom of the silicon wafer is captured with the visible light camera and the infrared camera.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wafer inspection technique, and more particularly to an apparatus for inspecting defects by taking an image below a wafer after a cutting or alignment process has been completed. [Background technology]

[0002] The wafer consists of a silicon wafer and a blue film placed on the bottom of it. The wafers requiring inspection are silicon wafers that have been placed on a blue film and then cut, or silicon wafers that have been cut and then arranged on a blue film to form a number of gaps therebetween. In particular, after the cutting or arranging process, the wafer has a number of gaps, and therefore a quality inspection is necessary.

[0003] In response to this, Patent Document 1 discloses an infiltration liquid refilling device, a refilling method, and a wafer cutting mark inspection device equipped with the infiltration liquid refilling device. In detail, Patent Document 1 discloses that when inspecting for defects or gaps on the downward surface of a wafer from below after the cutting or alignment process is completed, a wetting liquid is injected as a medium between the blue film below the wafer and the transparent sheet of the inspection device to improve the light transmittance to the blue film, thereby capturing a clear image before inspection.

[0004] Patent Document 1 discloses a technique for injecting an immersion liquid as a medium between the blue film and the transparent sheet of the inspection device, but does not disclose an imaging mechanism that can handle this situation. Specifically, when capturing images with visible light, the obstructed areas cannot be inspected due to lack of transparency. Therefore, there is a demand for technology to design wafers that can capture images evenly without obstructions based on the material properties of the wafer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Taiwan Patent No. I501334 Summary of the Invention [Problem to be solved by the invention]

[0006] A main object of the present invention is to provide an apparatus (wafer inspection apparatus) for inspecting defects on a wafer after a cutting or arrangement process has been completed. In the present invention, an apparatus for inspecting defects on wafers after cutting or alignment processes is incorporated with an immersion liquid detector, and an image of the bottom surface of the wafer is captured from below the wafer using visible and infrared light, and then inspected to reach a complete inspection result. [Means for solving the problem]

[0007] In order to solve the above problems, an apparatus for inspecting defects on a wafer after a cutting or alignment process is applied to inspect the wafer. The wafer comprises a silicon wafer that has been cut or aligned and a blue film attached to the bottom of the silicon wafer. An apparatus for inspecting defects on wafers after cutting or alignment includes an immersion liquid detector, a lens group, an optical lens group, a light source, a visible light camera, and an infrared camera. The infiltration fluid detector has a housing and a transparent cap. The housing has a perforation at the top. The perforation is covered with a transparent cap. The transparent cap is placed below the blue film and at a predetermined distance from the blue film. The liquid is positioned so that it flows and fills between the blue film and the transparent cap. The lens group is disposed beneath the transparent cap and within the housing. An optical lens group is disposed within the housing and below the lens group. The light source is disposed within the housing and emits visible light and infrared light to the outside through an optical lens group, the lens group and a transparent cap. The visible light camera is disposed within the housing, and captures visible light entering the housing from the outside using a group of optical lenses to take an image. The infrared camera is disposed within the housing, and captures infrared rays entering the housing from the outside using a group of optical lenses to take an image.

[0008] Specifically, the present invention incorporates an immersion liquid detector and captures images of the bottom surface of the wafer from below the wafer with visible and infrared light, and achieves complete inspection results by generating images at different depths with visible light having low wafer penetration and infrared light having high wafer penetration. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a first embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view showing a state in which a first embodiment of the present invention is used. [Diagram 3] FIG. 1 is a cross-sectional view showing a wafer in a first embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view showing a state after components have been added to the first embodiment of the present invention. [Diagram 5] FIG. 4 is a cross-sectional view showing a second embodiment of the present invention. [Figure 6] FIG. 4 is a cross-sectional view showing a wafer in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for inspecting defects on a wafer after a cutting or arrangement process according to the present invention will now be described in detail with reference to the accompanying drawings.

[0011] (First embodiment) The following description will be given with reference to FIG. 1 to FIG. The apparatus 10 for inspecting defects on a wafer after a cutting or arranging process according to the first embodiment is applied to inspect a wafer 91 after a cutting or arranging process. Wafer 91 includes a silicon wafer 92 after a cutting or alignment process, a blue film 94 attached to the bottom of silicon wafer 92, and a plurality of gaps 921 formed in silicon wafer 92 by the cutting or alignment process. The apparatus 10 for inspecting defects on wafers after cutting or arranging comprises an infiltrating liquid detector 11, a lens group (lens unit) 21, an optical lens group 31, a light source 41, a visible light camera 51, and an infrared camera 61.

[0012] The infiltration fluid detector 11 has a housing 12 and a transparent cap 16 . The housing 12 has a perforation 14 in the upper portion. The perforation 14 is covered with a transparent cap 16 . When performing the inspection, the transparent cap 16 is positioned below the blue film 94 at a predetermined distance from the blue film 94 . A liquid (not shown in the figure) is arranged to flow and fill the space between the blue film 94 and the transparent cap 16 . The infiltration liquid detector 11 is a well-known technology having a function of filling and recovering the infiltration liquid. The fact that the liquid medium flows between the blue film 94 and the transparent cap 16 and fills the space between them is also a well-known technique, and therefore, in this embodiment, explanation thereof using drawings or descriptions will be omitted.

[0013] Lens group 21 is disposed below transparent cap 16 and within housing 12 .

[0014] Optical lens group 31 is disposed within housing 12 and below lens group 21 . In the first embodiment, the optical lens group 31 includes a half mirror 32 and a spectroscopic mirror . The half mirror 32 reflects a part of the light beam from the light source 41 to the lens group 21 and transmits the remaining part. A light ray coming from the outside passes through the transparent cap 16 and the lens group 21 and hits the half mirror 32, after which a part of the light ray passes through the half mirror 32 and hits the spectroscopic mirror 34. The spectroscopic mirror 34 transmits visible light and reflects infrared light.

[0015] The light source 41 is disposed within the housing 12 and in this embodiment employs a halogen lamp that emits visible light and infrared light. The halogen lamp emits visible light and infrared rays to the outside through the optical lens group 31, the lens group 21 and the transparent cap 16. The light source 41 is not limited to a halogen lamp, but may be a mixed light source of an infrared light emitting diode and a visible light emitting diode.

[0016] The visible light camera 51 is disposed within the housing 12, and captures visible light entering the housing 12 from the outside using the optical lens 31, and then takes an image. More specifically, the visible light camera 51 captures visible light that passes through the spectroscopic mirror 34 toward the spectroscopic mirror 34 and then takes an image.

[0017] The infrared camera 61 is disposed within the housing 12, and captures infrared rays entering the housing 12 from the outside using the optical lens 31, and then takes an image. More specifically, the infrared camera 61 captures the infrared light that bounces off the spectroscopic mirror 34 toward the spectroscopic mirror 34, and then takes an image.

[0018] The visible light camera 51 and the infrared camera 61 have tube lenses 52 and 62, respectively. Since the light beams that bounce off the spectral mirror 34 or that pass through the spectral mirror 34 are captured by the tube lenses 52 and 62 and then an image is taken, the aiming function can be improved. The magnification of the tube lenses 52, 62 is determined by the expertise of the manufacturer.

[0019] The above is a description of the structure of the first embodiment. Next, a method of using the first embodiment will be explained.

[0020] The following description will be given with reference to FIG. Before taking an image, a liquid (not shown) is filled and allowed to flow between the blue film 94 at the bottom of the wafer 91 and the transparent cap 16 . If the refractive index of the liquid is similar to that of the transparent cap 16, the refraction of light can be significantly reduced and a clearer image can be captured than without the liquid. That is, since the prior art is disclosed in Patent Document 1, it is not shown in the drawings.

[0021] When an image is taken, visible light and infrared light from the light source 41 are reflected by the half mirror 32, a portion of which is emitted to the outside via the lens group 21 and the transparent cap 16, and then passes through the blue film 94, hits the bottom surface of the silicon wafer 92, and bounces off. When the reflected light passes through the transparent cap 16 and the lens group 21, then passes through the half mirror 32 and hits the spectroscopic mirror 34, the visible light camera 51 and the infrared camera 61 can capture the visible light and infrared light by the spectroscopic mirror 34 and take an image.

[0022] Description will be given with reference to FIG. 2 and FIG. The infrared rays have a relatively high transmittance through the silicon wafer 92, whereas the visible light has a relatively low transmittance through the silicon wafer 92. When taking an image, an image can be taken by reflecting visible light onto the bottom surface of the silicon wafer 92 and infrared light can be incident on the bottom surface of the silicon wafer 92 and partially passing through the bottom surface of the silicon wafer 92 to take an image. Since infrared light has a higher transmittance than visible light, the infrared image captured by the infrared camera 61 includes the bottom surface of the silicon wafer 92 and a part of the deep interior portion. In detail, when an image is taken of the gap 921 formed in the silicon wafer 92 by the cutting process, the infrared image captured by the infrared camera 61 includes the state of both side walls of the gap 921 of the silicon wafer 92 . By combining the image captured by the visible light camera 51 with the image captured by the infrared camera 61, it is possible to use image processing techniques to compare and determine whether there are any abnormalities or missing areas at the edges of the gaps 921 formed in the silicon wafer 92 by the cutting process.

[0023] As previously described, the present invention achieves a complete inspection result by incorporating an immersion fluid detector 11 and capturing images of the bottom surface of the wafer 91 from below the wafer 91 in visible and infrared light.

[0024] The following description will be given with reference to FIG. In the present invention, a reflecting mirror 36 is added to the optical lens group 31 . The reflecting mirror 36 reflects the infrared light reflected from the spectral mirror 34 at a different angle, and can change the shooting direction of the infrared camera 61 and the visible light camera 51 from a perpendicular state to a parallel state. Additionally, an autofocus laser 71 is added within the housing 12 to accommodate autofocus needs. The laser from the autofocus laser 71 hits the laser splitter mirror 72 and bounces off a transparent lens. Visible and infrared light can pass through the laser spectroscopic mirror 72 . To summarize the above, by adding the autofocus laser 71 and the laser spectroscopic mirror 72, it is possible to provide autofocus without affecting the irradiation of visible light and infrared light or the taking of images.

[0025] In this embodiment, since the visible light camera 51 cannot capture infrared light, if a half mirror is used instead of the spectral mirror 34 of the optical lens group 31, part of the light beam will hit the half mirror and bounce off, and another part will pass through the half mirror. If a light ray that hits the half mirror and bounces off, or a light ray that passes through the half mirror, enters the visible light camera 51, it can capture only visible light and take an image. If the light beam that bounces off the half mirror or the light beam that passes through the half mirror enters the infrared camera 61, it can capture only the infrared light and take an image. The above-mentioned method can be understood from FIG. 1 and FIG. 2, so the drawings and detailed description are omitted.

[0026] Second embodiment FIG. 5 is a cross-sectional view showing an apparatus 10' for inspecting defects on a wafer after a cutting or arranging process according to a second embodiment of the present invention. The differences from the first embodiment are as follows.

[0027] The second embodiment further comprises an upper light source 81'. An upper light source 81', a halogen lamp, is mounted above the wafer 91 and emits visible and infrared light. The upper light source 81 ′ irradiates light onto the lower transparent cap 16 ′ and the lens group 21 . The upper light source 81' is not limited to a halogen lamp, but may be a mixed light source of infrared light emitting diodes and visible light emitting diodes.

[0028] As shown in FIGS. 5 and 6, during inspection, the light beam from the upper light source 81' strikes the gaps 921 formed in the silicon wafer 92 by the sawing process. The light passing through the gap 921 serves as backlight for the visible light camera 51 ′ and the infrared camera 61 . When taking an image in backlight mode, the light source 41' can be shut down and the upper light source 81' can be activated, so that the visible light and the infrared light can be captured separately in backlight mode to take a backlight image. If only backlit images are to be taken in visible light, a visible light source may be used directly as the upper light source 81' without using a halogen lamp. If only infrared backlit images are to be taken, the infrared light source can be used directly as the upper light source 81'.

[0029] Other technical features and achieved effects of the second embodiment are the same as those of the first embodiment, so the description thereof will be omitted in this embodiment.

[0030] As described above, the present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0031] 10, 10': Equipment for inspecting defects on wafers after cutting or arranging process 11: Fluid Infiltration Detector 12: Housing 14: Perforation 16, 16': Transparent cap 21, 21': Lens group 31: Optical lens group 32: Half mirror 34: Spectroscopic mirror 36: Reflective mirror 41, 41': Light source 51, 51': Visible light camera 52: Tube lens 61, 61': Infrared camera 62: Tube lens 71: Autofocus laser 72: Laser spectroscopic mirror 81': Upper light source 91: Wafer 92: Silicon wafer 921: Gap 94: Blue Film

Claims

1. An apparatus for inspecting a wafer after a cutting or alignment process, the apparatus being applied to inspecting a wafer and including an infiltrating liquid detector, a lens group, an optical lens group, a light source, a visible light camera, and an infrared camera, The wafer includes a silicon wafer that has been cut or aligned, and a blue film attached to the bottom of the silicon wafer; the infiltration liquid detector has a housing and a transparent cap, the housing has a perforation at an upper portion, the perforation is covered by the transparent cap, the transparent cap is placed below the blue film and at a predetermined distance from the blue film, A liquid is arranged between the blue film and the transparent cap so as to flow and fill the space between the blue film and the transparent cap, the lens group is disposed below the transparent cap and within the housing; the optical lens group is disposed within the housing and below the lens group; the light source is disposed within the housing and emits visible light and infrared light to the outside through the optical lens group, the lens group, and the transparent cap; the visible light camera is disposed within the housing, and captures visible light entering the housing from the outside using the optical lens group to take an image; The infrared camera is disposed within the housing, and infrared light entering the housing from the outside is captured by the optical lens group and an image is taken.

2. the optical lens group has a half mirror and a spectroscopic mirror, the half mirror reflects a part of the light beam from the light source to the lens group and transmits the other part, A light ray coming from the outside passes through the transparent cap and the lens group and strikes the half mirror, and then a part of the light ray passes through the half mirror and strikes the spectroscopic mirror, 2. An apparatus for performing defect inspection on a wafer after a cutting or alignment process as described in claim 1, wherein the spectroscopic mirror passes visible light or infrared light, reflects another visible light or infrared light, and causes the visible light camera to capture the visible light and the infrared camera to capture the infrared light.

3. 3. An apparatus for performing defect inspection on a wafer after a cutting or alignment process as described in claim 2, wherein the optical lens group further includes a reflecting mirror, which reflects the light beam reflected from the spectroscopic mirror at a different angle to change the direction of irradiation.

4. the optical lens group has two half mirrors, one of which reflects a part of the light beam from the light source to the lens group and transmits the other part; A light ray coming from the outside passes through the transparent cap and the lens group and hits the half mirror, and then a part of the light ray passes through the half mirror and hits another half mirror, 2. An apparatus for inspecting defects on a wafer after a cutting or alignment process as described in claim 1, wherein another of the half mirrors reflects a portion of the light beam and transmits another portion of the light beam, and causes the reflected or transmitted light beam to be captured by the visible light camera and the other reflected or transmitted light beam to be captured by the infrared camera.

5. 5. An apparatus for performing defect inspection on a wafer after a cutting or alignment process as described in claim 4, characterized in that the optical lens group further includes a reflective mirror, which reflects the light beam reflected from another of the half mirrors at a different angle to change the direction of irradiation.

6. 2. The apparatus for inspecting defects on a wafer after a cutting or arranging process according to claim 1, wherein the light source is a halogen lamp.

7. It also has an upper light source, 2. The apparatus for inspecting defects on a wafer after a cutting or alignment process as described in claim 1, wherein the upper light source is placed above the wafer and irradiates light onto the transparent cap and the lens group below, the light including visible light and infrared light or only visible light.

8. 8. The apparatus for inspecting defects on a wafer after a cutting or arranging process according to claim 7, wherein the upper light source is a halogen lamp.

9. It also has an autofocus laser, the autofocus laser is disposed within the housing; The laser from the autofocus laser hits the laser spectroscopic mirror and bounces back to the lens group, 2. The apparatus for inspecting defects on a wafer after a cutting or arranging process according to claim 1, wherein the laser spectroscopic mirror transmits visible light and infrared light.

10. 2. The apparatus for performing defect inspection on a wafer after a cutting or alignment process as claimed in claim 1, wherein the visible light camera and the infrared camera each capture a light beam reflected from the optical lens group or a light beam passing through the optical lens group by a tube lens and then take an image.

Images