Semiconductor device and cutting equipment for cutting semiconductor device

Abstract

A method for cutting a semiconductor device is provided. The device includes a first semiconductor layer, an insulation layer, and a second semiconductor layer. The method includes the steps of: forming a semiconductor part in the first semiconductor layer; irradiating a laser beam on a surface of the first semiconductor layer; and cutting the device into a semiconductor chip by using the laser beam. The laser beam is reflected at an interface so that a first reflected beam is generated, and the laser beam is reflected at another interface so that a second reflected beam is generated. The insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.

1 - 22 . (canceled)  
     
     
         23 . A semiconductor device comprising: 
 a substrate including a first semiconductor layer, an insulation layer, and a second semiconductor layer, which are laminated in this order;    a semiconductor part disposed in the first semiconductor layer; and    a cut portion for cutting the substrate into a semiconductor chip by using a laser beam,    wherein the first semiconductor layer, the insulation layer, and the second semiconductor layer have predetermined refractive indexes, respectively, which perform that the laser beam is reflected at an interface between the first semiconductor layer and the insulation layer so that a first reflected beam is generated, and that the laser beam is reflected at an interface between the insulation layer and the second semiconductor layer so that a second reflected beam is generated, and    wherein the insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.    
     
     
         24 . The device according to  claim 23 , 
 wherein the thickness of the insulation film is equal to an integral multiple of a wavelength of the laser beam so that the phase of the first reflected beam is opposite to the phase of the second reflected beam.    
     
     
         25 . The device according to  claim 23 , 
 wherein the thickness of the insulation film, which is parallel to the laser beam, is defined as D BOX ,    wherein the laser beam has a wavelength defined as λ,    wherein the insulation film has a refractive index defined as N BOX ,    wherein the thickness of the insulation film is in a range between Mλ/2N BOX −λ/4 and Mλ/2N BOX +λ/4, and    wherein M represents a natural number.    
     
     
         26 . The device according to  claim 23 , 
 wherein the thickness of the insulation film, which is parallel to the laser beam, is in a range between 1000 nm and 1200 nm.    
     
     
         27 . The device according to  claim 23 , further comprising: 
 an anti-reflection film on the surface of the first semiconductor layer for being capable of irradiating the laser beam on the first semiconductor layer through the anti-reflection film,    wherein the anti-reflection film and the first semiconductor layer have predetermined refractive indexes, respectively, which perform that the laser beam is reflected at an interface between the anti-reflection film and the first semiconductor layer so that a third reflected beam is generated, and that the laser beam is reflected on the anti-reflection film so that a fourth reflected beam is generated, and    wherein the anti-reflection film has a thickness, which is determined to weaken the third and fourth reflected beams each other.    
     
     
         28 . The device according to  claim 23 , 
 wherein the first semiconductor layer is a SOI layer, and the second semiconductor layer is a support substrate made of silicon,    wherein the insulation film is made of silicon oxide, and    wherein the substrate is formed from a SOI substrate.    
     
     
         29 . A semiconductor device comprising: 
 a substrate including a first semiconductor layer, an insulation layer, and a second semiconductor layer, which are laminated in this order;    a semiconductor part disposed in the first semiconductor layer;    a cut portion for cutting the substrate into a semiconductor chip by using a laser beam; and    an anti-reflection film on the surface of the first semiconductor layer for being capable of irradiating the laser beam on the first semiconductor layer through the anti-reflection film,    wherein the anti-reflection film and the first semiconductor layer have predetermined refractive indexes, respectively, which perform that the laser beam is reflected at an interface between the anti-reflection film and the first semiconductor layer so that a third reflected beam is generated, and that the laser beam is reflected on the anti-reflection film so that a fourth reflected beam is generated, and    wherein the anti-reflection film has a thickness, which is determined to weaken the third and fourth reflected beams each other.    
     
     
         30 . The device according to  claim 29 , 
 wherein the thickness of the anti-reflection film is equal to a half of a wavelength of the laser beam so that a phase of the third reflected beam is opposite to a phase of the fourth reflected beam.    
     
     
         31 . The device according to  claim 29 , 
 wherein the thickness of the anti-reflection film, which is parallel to the laser beam, is defined as D AN ,    wherein the laser beam has a wavelength defined as λ,    wherein the anti-reflection film has a refractive index defined as N AN ,    wherein the thickness of the anti-reflection film is in a range between (M−0.5)λ/2N AN −λ/4 and (M−0.5)λ/2N AN +λ/4, and    wherein M represents a natural number.    
     
     
         32 . The device according to  claim 31 , 
 wherein the refractive index of the anti-reflection film is in a range between 1 and 3.5.    
     
     
         33 . The device according to  claim 29 , 
 wherein the substrate is capable of cutting by the laser beam in air or vacuum, and    wherein the anti-reflection film is made of a material having a refractive index substantially equal to a square root of a refractive index of silicon.    
     
     
         34 . The device according to  claim 29 , 
 wherein the anti-reflection film is formed of a single layer film of a SiN film, a SiO 2  film, or a SiON film.    
     
     
         35 . The device according to  claim 29 , 
 wherein the anti-reflection film is formed of a multi-layer film including at least two types of films selected in a group including a SiN film, a SiO 2  film, and a SiON film.    
     
     
         36 . The device according to  claim 29 , 
 wherein the first semiconductor layer is a SOI layer, and the second semiconductor layer is a support substrate made of silicon,    wherein the insulation film is made of silicon oxide, and    wherein the substrate is formed from a SOI substrate.    
     
     
         37 . Cutting equipment for cutting a semiconductor device comprising a first semiconductor layer, an insulation layer, and a second semiconductor layer, which are laminated in this order, the equipment comprising: 
 a laser for irradiating a laser beam on a surface of the first semiconductor layer so that the device is cut into a semiconductor chip,    wherein the laser beam is reflected at an interface between the first semiconductor layer and the insulation layer so that a first reflected beam is generated, and the laser beam is reflected at an interface between the insulation layer and the second semiconductor layer so that a second reflected beam is generated, and    wherein the insulation film has a thickness, which is determined to weaken the first and second reflected beams each other.    
     
     
         38 . The equipment according to  claim 37 , 
 wherein the thickness of the insulation film is equal to an integral multiple of a wavelength of the laser beam so that a phase of the first reflected beam is opposite to a phase of the second reflected beam.    
     
     
         39 . The equipment according to  claim 37 , 
 wherein the thickness of the insulation film, which is parallel to the laser beam, is defined as D BOX ,    wherein the laser beam has a wavelength defined as λ,    wherein the insulation film has a refractive index defined as N BOX ,    wherein the thickness of the insulation film is in a range between Mλ/2N BOX −λ/4 and Mλ/2N BOX +λ/4, and    wherein M represents a natural number.    
     
     
         40 . The equipment according to  claim 37 , 
 wherein the thickness of the insulation film, which is parallel to the laser beam, is in a range between 1000 nm and 1200 nm.    
     
     
         41 . The equipment according to  claim 37 , 
 wherein the device further includes an anti-reflection film on the surface of the first semiconductor layer so that the laser beam is irradiated on the first semiconductor layer through the anti-reflection film,    wherein the laser beam is reflected at an interface between the anti-reflection film and the first semiconductor layer so that a third reflected beam is generated, and the laser beam is reflected on the anti-reflection film so that a fourth reflected beam is generated, and    wherein the anti-reflection film has a thickness, which is determined to weaken the third and fourth reflected beams each other.    
     
     
         42 . The equipment according to  claim 37 , further comprising: 
 a detector for measuring a reflection coefficient of the laser beam; and    a controller for controlling a laser power of the laser beam on the basis of the reflection coefficient.    
     
     
         43 . The equipment according to  claim 42 , 
 wherein the reflection coefficient is measured so that a reflection coefficient mapping of a whole surface of the semiconductor device is obtained.    
     
     
         44 . The equipment according to  claim 43 , 
 wherein the laser power of the laser beam is controlled on the basis of the reflection coefficient mapping so that the laser power is adjusted to be an optimum laser power corresponding to the reflection coefficient.    
     
     
         45 . The equipment according to  claim 42 , 
 wherein the controller controls the laser power of the laser beam on the basis of the reflection coefficient together with measuring the reflection coefficient by the detector so that the semiconductor device is cut into the semiconductor chip.    
     
     
         46 . The equipment according to  claim 37 , 
 wherein the first semiconductor layer is a SOI layer, and the second semiconductor layer is a support substrate made of silicon,    wherein the insulation film is made of silicon oxide, and    wherein the device is formed from a SOI substrate.    
     
     
         47 . Cutting equipment for cutting a semiconductor device comprising a first semiconductor layer, an insulation layer, and a second semiconductor layer, which are laminated in this order, the equipment comprising: 
 a laser for irradiating a laser beam on a surface of the first semiconductor layer so that the device is cut into a semiconductor chip,    wherein the device further includes an anti-reflection film on the surface of the first semiconductor layer so that the laser beam is irradiated on the first semiconductor layer through the anti-reflection film,    wherein the laser beam is reflected at an interface between the anti-reflection film and the first semiconductor layer so that a third reflected beam is generated, and the laser beam is reflected on the anti-reflection film so that a fourth reflected beam is generated, and    wherein the anti-reflection film has a thickness, which is determined to weaken the third and fourth reflected beams each other.    
     
     
         48 . The equipment according to  claim 47 , 
 wherein the thickness of the anti-reflection film is equal to a half of a wavelength of the laser beam so that a phase of the third reflected beam is opposite to a phase of the fourth reflected beam.    
     
     
         49 . The equipment according to  claim 47 , 
 wherein the thickness of the anti-reflection film, which is parallel to the laser beam, is defined as D AN ,    wherein the laser beam has a wavelength defined as λ,    wherein the anti-reflection film has a refractive index defined as N AN ,    wherein the thickness of the anti-reflection film is in a range between (M−0.5)λ/2N AN −λ/4 and (M−0.5)λ/2N AN +λ/4, and    wherein M represents a natural number.    
     
     
         50 . The equipment according to  claim 49 , 
 wherein the refractive index of the anti-reflection film is in a range between 1 and 3.5.    
     
     
         51 . The equipment according to  claim 47 , 
 wherein the laser beam is irradiated on the first layer in air or vacuum, and    wherein the anti-reflection film is made of a material having a refractive index substantially equal to a square root of a refractive index of silicon.    
     
     
         52 . The equipment according to  claim 47 , 
 wherein the anti-reflection film is formed of a single layer film of a SIN film, a SiO 2  film, or a SION film.    
     
     
         53 . The equipment according to  claim 47 , 
 wherein the anti-reflection film is formed of a multi-layer film including at least two types of films selected in a group including a SiN film, a SiO 2  film, and a SION film.    
     
     
         54 . The equipment according to  claim 47 , further comprising: 
 a detector for measuring a reflection coefficient of the laser beam; and    a controller for controlling a laser power of the laser beam on the basis of the reflection coefficient.    
     
     
         55 . The equipment according to  claim 54 , 
 wherein the reflection coefficient is measured so that a reflection coefficient mapping of a whole surface of the semiconductor device is obtained.    
     
     
         56 . The equipment according to  claim 55 , 
 wherein the laser power of the laser beam is controlled on the basis of the reflection coefficient mapping so that the laser power is adjusted to be an optimum laser power corresponding to the reflection coefficient.    
     
     
         57 . The equipment according to  claim 54 , 
 wherein the controller controls the laser power of the laser beam on the basis of the reflection coefficient together with measuring the reflection coefficient by the detector so that the semiconductor device is cut into the semiconductor chip.    
     
     
         58 . The equipment according to  claim 47 , 
 wherein the first semiconductor layer is a SOI layer, and the second semiconductor layer is a support substrate made of silicon,    wherein the insulation film is made of silicon oxide, and wherein the device is formed from a SOI substrate.