JP2009146990A - Cutting method of tape or film affixed to wafer - Google Patents

Abstract

A method for cutting a tape or a film attached to a wafer without causing the chipping or cracking of the wafer is provided.
A method for cutting a tape or a film 2 according to the present invention provides a constant angle 9 between a cutting edge of a cutting tool for cutting a wafer 1 and a tangent to the outer periphery of the wafer. The tape or film 2 attached to 1 is cut larger than the outer diameter of the wafer 1. As a result, the cutting edge 3 of the cutting tool does not directly contact the end surface portion of the wafer 1.
[Selection] Figure 1

Description

  The present invention relates to a method for cutting a tape or a film attached to a wafer at the time of manufacturing a semiconductor.

  2. Description of the Related Art In a manufacturing method of a semiconductor device, on an imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor formed on a wafer, a property of preventing light from adhering to the imaging device and transmitting light A glass substrate is formed. In order to provide a gap so that the glass substrate does not directly touch the image sensor, a photosensitive resin film is pasted on the image sensor, the film is patterned so that the image area opens, and the glass remaining on the outer periphery of the image area is glass. It has a structure that supports the substrate.

  Recent imaging devices are not only mounted on cameras and video cameras, but are also modularized with other components and incorporated into mobile phones. Due to the size of the housing to be incorporated, the thickness of the image sensor is required to be as thin as about 200 μm or less. In order to cope with the thinning, it is necessary to grind the wafer on which the image sensor is formed. When wafer grinding is performed after the glass substrate is formed on the image sensor, the uniformity of the grinding amount in the wafer surface is poor. For this reason, a method of forming a glass substrate after wafer grinding is generally used.

  The end surface of the wafer is usually chamfered in order to prevent cracking and chipping of the wafer during conveyance and processing. However, when wafer grinding is performed to cope with the thinning of the device, the bottom of the wafer end surface has a sharp shape. The above-mentioned photosensitive resin film is attached to a wafer having such a shape that the bottom of the end face is pointed, and the film is cut along the outer diameter of the wafer.

  As this cutting method, as shown in FIG. 2, there is a method of cutting the tape or film along the outer diameter of the wafer with the cutting edge of the cutting tool directed in the tangential direction of the outer periphery of the wafer. In this method, since the sharp cutting edge of the cutting tool is always in direct contact with the wafer end surface portion, chipping or cracking of the wafer is likely to occur.

There is also a method for cutting a tape or film by adjusting an inclination angle between a cutting tool and a wafer surface described in Patent Document 1.
JP 2000-353682 (published on December 19, 2000)

  However, in the above-described method of adjusting the inclination angle of the cutting tool and cutting the tape or film along the wafer outer diameter, the cutting tool is inclined at the time of film cutting. The area in direct contact with the wafer becomes large, and the wafer is likely to be chipped or cracked. Further, in the film cutting in the case where a tape or a film is pasted after the wafer grinding in which the bottom of the wafer end surface is sharp, the wafer is more likely to be chipped or broken.

  Therefore, the present invention has been made in view of the above problems, and its purpose is to cut a tape or a film attached to an extremely thin wafer without causing the wafer to chip or crack. It is to provide.

  The tape or film cutting method of the present invention is characterized in that the tape or film attached to the wafer is cut larger than the outer diameter of the wafer in order to solve the above-mentioned problems.

  According to said structure, this invention is a method of cut | disconnecting the tape or film affixed on the wafer. Here, when the tape or film is cut, if the cutting edge of the cutting tool is cut while being in contact with the outer diameter of the wafer, the cutting edge of the cutting tool comes into direct contact with the wafer end surface. As a result, the wafer end face is damaged, causing chipping and cracking.

  Therefore, in the present invention, the tape or film attached to the wafer surface is cut larger than the outer diameter of the wafer. For example, by cutting the tape or film at the limit where the cutting edge of the cutting tool is in contact with the outer diameter of the wafer, the tape or film can be cut out larger than the outer diameter of the wafer.

  In order to realize such cutting, for example, a certain angle is provided between the cutting edge of the cutting tool and the tangent to the outer periphery of the wafer. This angle may be adjusted according to the final thickness of the wafer and the shape of the end surface portion of the wafer, or may be adjusted according to a certain angle between the cutting tool and the front and back surfaces of the wafer. As a result, the tape or film can be cut without the sharp cutting edge of the cutting tool coming into direct contact with the wafer end face.

  Further, by cutting the tape or film larger than the outer diameter of the wafer, for example, the wafer end surface portion can be completely covered with the tape or film. For this reason, a cutting tool contacts a wafer end surface part through a tape or a film. When the cutting tool comes into contact with the film, the impact on the wafer when the tape or the film is cut can be reduced, and the chipping or cracking of the wafer can be prevented.

  In the method for cutting a tape or film of the present invention, a certain angle is further provided between the cutting edge of a cutting tool for cutting the tape or the film and a tangent line on the outer periphery of the wafer, and the tape or the film It is preferable to cut the film.

  According to said structure, when a tape or a film is cut | disconnected, a fixed angle is provided between the blade edge | tip of a cutting tool, and the tangent of a wafer outer periphery. This angle may be about 3 °, for example. By providing such an angle, it is possible to cut the film without bringing the cutting edge into direct contact with the wafer end face portion, as compared to when cutting the cutting edge of the cutting tool toward the tangential direction of the outer periphery of the wafer. Therefore, chipping and cracking of the wafer can be prevented.

  In the method for cutting a tape or film of the present invention, it is preferable that the angle is further adjusted according to the final thickness of the wafer and the shape of the end surface portion of the wafer.

  According to said structure, the fixed angle between the blade edge | tip of a cutting tool and the tangent of a wafer outer periphery is adjusted according to the thickness of a wafer, and the shape of an end surface part. As described above, in the present invention, the wafer end surface portion can be covered by cutting the tape or film larger than the wafer. Therefore, the cutting angle of the tape or film is adjusted according to the thickness or shape of the wafer. As a result, the wafer end surface can be covered with a tape or a film. Therefore, the sharp cutting edge of the cutting tool does not directly contact the wafer end surface portion.

  In the tape or film cutting method of the present invention, it is preferable that the angle is further adjusted according to a certain angle between the cutting tool and the front and back surfaces of the wafer.

  According to said structure, the angle between the blade edge | tip of a cutting tool and the tangent of a wafer outer periphery is adjusted according to the angle between a cutting tool and a wafer front and back. For example, the angle between the cutting tool and the front and back surfaces of the wafer may be vertical, or the cutting tool may be inclined. In any case, in order to cut the film larger than the wafer outer diameter, an angle between the cutting edge of the cutting tool and the tangent to the outer periphery of the wafer is provided. Therefore, the sharp cutting edge of the cutting tool does not directly contact the wafer end surface portion.

  As described above, the tape or film cutting method of the present invention is a cutting method that suppresses the occurrence of chipping or cracking of the wafer by cutting the tape or film affixed to the wafer larger than the wafer. For this reason, it is possible to easily cut a film that requires careful attention in an imaging device such as a CCD or CMOS image sensor that requires thinning.

  In addition, the yield of the device can be stabilized and improved by easily preventing the wafer from being chipped or cracked.

  An embodiment of the tape or film cutting method according to the present invention will be described below with reference to FIGS. 1 and 3 to 6.

  The cutting method of the tape or film 2 of the present invention is a method of cutting the tape or film 2 attached to the wafer 1 to be larger than the outer diameter of the wafer 1. As used herein, “cutting larger than the outer diameter of the wafer 1” means that the outer shape of the cut tape or film 2 becomes longer than the outer shape of the wafer 1 by cutting the tape or film 2 larger than the wafer 1. It means to do so. In order to realize such cutting, specifically, a fixed angle 9 between the cutting edge of the cutting tool and the tangent to the outer periphery of the wafer is provided, and the tape affixed to the wafer 1 while maintaining the angle 9 or The film 2 is cut.

(Wafer 1)
FIG. 3 is a view showing a cross-sectional shape of the wafer 1 ground to a thickness of about 200 μm. The hatched portion at the bottom of this figure corresponds to the ground wafer region 6. As shown in this figure, the wafer 1 is greatly ground to a thickness of about 200 μm. This is because the thickness of an image sensor such as a CCD or a CMOS image sensor is required to be thin due to the size of the housing in which the wafer 1 is incorporated. For this reason, the bottom part of the end surface of the wafer 1 has a sharp shape, and when the cutting edge of the cutting tool is in direct contact, chipping or cracking is likely to occur.

(Attaching method of tape or film 2)
FIG. 4 is a diagram illustrating a method of attaching the tape or film 2 to the wafer 1. As shown in this figure, a photosensitive resin film 7 is provided on the wafer 1, and the film 7 is attached to the wafer 1 by an attaching roller 8. The wafer 1 is fixed to a bonding device for the photosensitive resin film 7 with the imaging element forming surface facing up. By rotating the attaching roller 8, the photosensitive resin film 7 is attached not only to the surface of the wafer 1 but also to the end surface portion of the wafer 1.

(Tape or film 2 cutting method)
FIG. 1 is a top view of the method for cutting a tape or film 2 of the present invention. As shown in this figure, in order to cut the tape or film 2 larger than the outer diameter of the wafer 1, a certain angle 9 is provided between the cutting edge of the cutting tool and the tangent to the outer periphery of the wafer, and the angle 9 is maintained. Then, the tape or film 2 attached to the wafer 1 is cut. A photosensitive resin film 7 is attached to the wafer 1. When the film 7 is cut, an angle 9 between the cutting edge 3 of the cutting tool and the tangent to the outer periphery of the wafer is provided at about 3 °. While maintaining this state, the cutting edge 3 of the cutting tool is rotated in the cutting direction 5 to cut the photosensitive resin film 7 larger than the outer diameter of the wafer 1. By providing the angle 9, the photosensitive resin film 7 is cut out larger than the outer diameter of the wafer 1.

  Here, the angle 9 between the cutting edge 3 of the cutting tool and the tangent to the outer periphery of the wafer is about 3 °, but this angle may be adjusted according to the thickness of the wafer 1 and the shape of the end face.

  5 and 6 are cross-sectional views of a method for cutting the tape or film 2 attached to the wafer 1 after grinding. In FIG. 5, the angle 10 between the cutting tool and the front and back surfaces of the wafer 1 is vertical, and in FIG. 6, it is not vertical. As shown in this figure, when the photosensitive resin film 7 is cut, the angle 10 between the cutting tool and the front and back surfaces of the wafer may be vertical as shown in FIG. 5, or the cutting tool is inclined as shown in FIG. Also good. In any case, in order to cut the photosensitive resin film 7 larger than the outer diameter of the wafer 1, the angle 9 between the cutting edge of the cutting tool and the tangent to the outer periphery of the wafer is set to about 3 °.

  Thus, when the photosensitive resin film 7 is cut out larger than the outer diameter of the wafer 1, the photosensitive resin film 7 is completely covered to the bottom of the end surface of the wafer 1 having a sharp shape. For this reason, the cutting tool does not directly contact the end surface portion of the wafer 1 but contacts the end surface portion of the wafer 1 through the photosensitive resin film 7. Thereby, the impact on the wafer 1 when the photosensitive resin film 7 is cut can be reduced, and the occurrence of chipping or cracking of the wafer 1 can be suppressed.

  Further, when the photosensitive resin film 7 is cut, the angle 9 between the cutting edge of the cutting tool and the tangent on the outer periphery of the wafer is different from the case where the cutting edge 3 of the cutting tool is directed in the direction of the tangent 4 on the outer periphery of the wafer. By providing, the cutting edge 3 of the cutting tool does not directly contact the end surface portion of the wafer 1. Furthermore, since the cutting tool is separated from the end surface portion of the wafer 1 by providing the angle 9, an area where the cutting tool directly contacts the end surface portion of the wafer 1 through the photosensitive resin film 7 is reduced. Therefore, it is possible to prevent the wafer 1 from being chipped or cracked when the photosensitive resin film 7 is cut.

(Image sensor creation process)
Thereafter, the photosensitive resin film 7 is irradiated with UV (Ultra Violet) light and patterned so as to open the imaging region. At this time, the photosensitive resin film 7 is left on the outer periphery of the imaging region. And it is set as the structure which supports the glass substrate formed on an image pick-up element. After forming the glass substrate, the wafer 1 is diced and divided into individual image sensors.

(Cutting method with pre-grinding wafer 1)
FIG. 7 is a cross-sectional view of a method for cutting the tape or film 2 attached to the pre-grinding wafer 1. As shown in this figure, the wafer 1 used here is in a state before grinding the wafer region 6 which was the hatched portion in FIG. A protective tape 11 is affixed to the surface of the wafer 1. The method for cutting the protective tape 11 is similar to the method in which the wafer 1 is ground and the film 2 is pasted. Thus, the protective tape 11 is cut larger than the outer diameter of the wafer 1. Is provided.

  As described above, the present invention can also be applied when the protective tape 11 attached to the surface of the wafer 1 before grinding is cut with a cutting tool. Thereby, chipping and cracking of the wafer 1 can be reduced.

  If the method for cutting a tape or film according to the present invention is used, it is possible to prevent a wafer from being chipped or cracked in the manufacturing process of a semiconductor device, and to be applied to the manufacture of an image sensor that requires thinning.

It is a top view of the tape or film cutting method in the embodiment of the present invention. It is a top view of the tape or film cutting method in a prior art. It is a wafer sectional view after grinding in an embodiment of the present invention. It is a figure which shows the sticking method of the tape or film in embodiment of this invention. It is sectional drawing of the tape or film cutting method affixed on the wafer after grinding in embodiment of this invention. It is sectional drawing of the tape or film cutting method affixed on the wafer after grinding in embodiment of this invention. It is sectional drawing of the tape or film cutting method affixed on the wafer before grinding in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer 2 Tape or film 3 Cutting tool edge 4 Wafer circumference tangent line 5 Cutting tool cutting direction 6 Ground wafer area 7 Photosensitive resin film 8 Adhering roller 9 Between cutting tool edge and wafer circumference tangent Angle 10 Angle between cutting tool and wafer front and back 11 Protection tape

Claims (4)

  A cutting method characterized by cutting a tape or film affixed to a wafer larger than the outer diameter of the wafer.   The tape or the film is cut by providing a certain angle between a cutting edge of a cutting tool for cutting the tape or the film and a tangent line on the outer periphery of the wafer. Cutting method.   The cutting method according to claim 2, wherein the angle is adjusted according to a final thickness of the wafer and a shape of an end surface portion of the wafer.   The cutting method according to claim 2, wherein the angle is adjusted according to an angle between the cutting tool and the front and back surfaces of the wafer.

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