Abstract: A method of cutting an object which can accurately cut the object is provided. An object to be processed 1 such as a silicon wafer is irradiated with laser light L while a light-converging point P is positioned therewithin, so as to form a modified region 7 due to multiphoton absorption within the object 1, and cause the modified region 7 to form a starting point region for cutting 8 shifted from the center line CL of the thickness of the object 1 toward the front face 3 of the object 1 along a line along which the object should be cut. Subsequently, the object 1 is pressed from the rear face 21 side thereof. This can generate a fracture from the starting point region for cutting 8 acting as a start point, thereby accurately cutting the object 1 along the line along which the object should be cut.

Abstract: An ultraviolet light generating target 20 includes a substrate 21 made of sapphire, quartz, or rock crystal; and a light-emitting layer 22 that is provided on the substrate 21 and that generates ultraviolet light upon receiving an electron beam. The light-emitting layer 22 includes powdered or granular Pr:LuAG crystals. By using such a light-emitting layer 22 as the target, the ultraviolet light generating efficiency can be increased more remarkably than when a Pr:LuAG single crystal film is used.

Abstract: An ultraviolet light generating target 20 includes a substrate 21 made of sapphire, quartz or rock crystal; and a Pr:LuAG polycrystalline film 22, provided on the substrate 21, that generates ultraviolet light upon receiving an electron beam. By using a Pr:LuAG polycrystal as the target, the ultraviolet light generating efficiency can be increased more remarkably than when a Pr:LuAG single crystal film is used.

Abstract: A laser processing method which can efficiently perform laser processing while minimizing the deviation of the converging point of a laser beam in end parts of an object to be processed is provided.

Abstract: A method of cutting an object which can accurately cut the object is provided. An object to be processed 1 such as a silicon wafer is irradiated with laser light L while a light-converging point P is positioned therewithin, so as to form a modified region 7 due to multiphoton absorption within the object 1, and cause the modified region 7 to form a starting point region for cutting 8 shifted from the center line CL of the thickness of the object 1 toward the front face 3 of the object 1 along a line along which the object should be cut. Subsequently, the object 1 is pressed from the rear face 21 side thereof. This can generate a fracture from the starting point region for cutting 8 acting as a start point, thereby accurately cutting the object 1 along the line along which the object should be cut.

Abstract: A laser processing method which can highly accurately cut objects to be processed having various laminate structures is provided. An object to be processed comprising a substrate and a laminate part disposed on the front face of the substrate is irradiated with laser light L while a light-converging point P is positioned at least within the substrate, so as to form a modified region due to multiphoton absorption at least within the substrate, and cause the modified region to form a starting point region for cutting. When the object is cut along the starting point region for cutting, the object 1 can be cut with a high accuracy.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

Abstract: A method of cutting an object which can accurately cut the object is provided. An object to be processed 1 such as a silicon wafer is irradiated with laser light L while a light-converging point P is positioned therewithin, so as to form a modified region 7 due to multiphoton absorption within the object 1, and cause the modified region 7 to form a starting point region for cutting 8 shifted from the center line CL of the thickness of the object 1 toward the front face 3 of the object 1 along a line along which the object should be cut. Subsequently, the object 1 is pressed from the rear face 21 side thereof. This can generate a fracture from the starting point region for cutting 8 acting as a start point, thereby accurately cutting the object 1 along the line along which the object should be cut.

Abstract: A wafer having a front face formed with a functional device is irradiated with laser light while positioning a light-converging point within the wafer with the rear face of the wafer acting as a laser light incident face, so as to generate multiphoton absorption, thereby forming a starting point region for cutting due to a molten processed region within the wafer along a line. Consequently, a fracture can be generated from the starting point region for cutting naturally or with a relatively small force, so as to reach the front face and rear face. Therefore, when an expansion film is attached to the rear face of the wafer by way of a die bonding resin layer after forming the starting point region for cutting and then expanded, the wafer and die bonding resin layer can be cut along the line.

Abstract: A laser processing method which can highly accurately cut objects to be processed having various laminate structures is provided. An object to be processed comprising a substrate and a laminate part disposed on the front face of the substrate is irradiated with laser light L while a light-converging point P is positioned at least within the substrate, so as to form a modified region due to multiphoton absorption at least within the substrate, and cause the modified region to form a starting point region for cutting. When the object is cut along the starting point region for cutting, the object 1 can be cut with a high accuracy.

Abstract: Multiphoton absorption is generated, so as to form a part which is intended to be cut 9 due to a molten processed region 13 within a silicon wafer 11, and then an adhesive sheet 20 bonded to the silicon wafer 11 is expanded. This cuts the silicon wafer 11 along the part which is intended to be cut 9 with a high precision into semiconductor chips 25. Here, opposing cut sections 25a, 25a of neighboring semiconductor chips 25, 25 are separated from each other from their close contact state, whereby a die-bonding resin layer 23 is also cut along the part which is intended to be cut 9. Therefore, the silicon wafer 11 and die-bonding resin layer 23 can be cut much more efficiently than in the case where the silicon wafer 11 and die-bonding resin layer 23 are cut with a blade without cutting a base 21.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

Abstract: Multiphoton absorption is generated, so as to form a part which is intended to be cut 9 due to a molten processed region 13 within a silicon wafer 11, and then an adhesive sheet 20 bonded to the silicon wafer 11 is expanded. This cuts the silicon wafer 11 along the part which is intended to be cut 9 with a high precision into semiconductor chips 25. Here, opposing cut sections 25a, 25a of neighboring semiconductor chips 25, 25 are separated from each other from their close contact state, whereby a die-bonding resin layer 23 is also cut along the part which is intended to be cut 9. Therefore, the silicon wafer 11 and die-bonding resin layer 23 can be cut much more efficiently than in the case where the silicon wafer 11 and die-bonding resin layer 23 are cut with a blade without cutting a base 21.

Abstract: Multiphoton absorption is generated, so as to form a part which is intended to be cut 9 due to a molten processed region 13 within a silicon wafer 11, and then an adhesive sheet 20 bonded to the silicon wafer 11 is expanded. This cuts the silicon wafer 11 along the part which is intended to be cut 9 with a high precision into semiconductor chips 25. Here, opposing cut sections 25a, 25a of neighboring semiconductor chips 25, 25 are separated from each other from their close contact state, whereby a die-bonding resin layer 23 is also cut along the part which is intended to be cut 9. Therefore, the silicon wafer 11 and die-bonding resin layer 23 can be cut much more efficiently than in the case where the silicon wafer 11 and die-bonding resin layer 23 are cut with a blade without cutting a base 21.

Abstract: A laser processing method which can highly accurately cut objects to be processed having various laminate structures is provided. An object to be processed comprising a substrate and a laminate part disposed on the front face of the substrate is irradiated with laser light L while a light-converging point P is positioned at least within the substrate, so as to form a modified region due to multiphoton absorption at least within the substrate, and cause the modified region to form a starting point region for cutting. When the object is cut along the starting point region for cutting, the object 1 can be cut with a high accuracy.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

Abstract: A laser processing method comprising a step of irradiating an object to be processed with laser light elliptically polarized with an ellipticity of other than 1 such that a light-converging point of the laser light is located within the object along the major axis of an ellipse indicative of the elliptical polarization of laser light, along a line which the object is intended to be cut, to form a modified region caused by multiphoton absorption within the object, along the line which the object is intended to be cut.

Abstract: A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.