Scribing sapphire substrates with a solid state uv laser

Abstract

A process and system scribe sapphire substrates, by performing the steps of mounting a sapphire substrate, carrying an array of integrated device die, on a stage such as a movable X-Y stage including a vacuum chuck; and directing UV pulses of laser energy directed at a surface of the sapphire substrate using a solid-state laser. The pulses of laser energy have a wavelength below about 560 nanometers, and preferably between about 150 in 560 nanometers. In addition, energy density, spot size, and pulse duration are established at levels sufficient to induce ablation of sapphire. Control of the system, such as by moving the stage with a stationary beam path for the pulses, causes the pulses to contact the sapphire substrate in a scribe pattern at a rate of motion causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate.

1 . A system for scribing a sapphire substrate, comprising: 
 a laser generating pulses of laser energy in a wavelength less than about 560 nanometers;    a stage adapted to support, and move, a sapphire substrate;    optics directing the pulses to impact a sapphire substrate mounted on the stage; and    a control system coupled to the solid state laser and the stage, the control system controlling the laser and stage, and causing the pulses to impact the sapphire substrate having a peak power density of about 10 GW/cm 2  or less at a repetition rate of greater than 5 kHz in a scribe pattern at a rate of motion causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate.    
     
     
         2 . The system of  claim 1 , wherein the control system controls a rate of motion of the stage, causing overlap of successive pulses.  
     
     
         3 . A system for scribing a sapphire substrate, comprising: 
 a laser generating pulses of laser energy in a wavelength less than about 560 nanometers;    a stage adapted to support, and move, a sapphire substrate;    optics directing the pulses to impact a sapphire substrate mounted on the stage; and    a control system coupled to the solid state laser and the stage, the control system controlling the laser and stage, and causing the pulses to impact the sapphire substrate having a peak power density of about 10 GW/cm 2  or less at a repetition rate of greater than 5 kHz in a scribe pattern at a rate of motion causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate; and    an edge detection system which detects edges of a substrate mounting on the stage during movement of the stage, preventing said pulses from being directed off the substrate.    
     
     
         4 . The system of  claim 3 , including a debris exhaust system.  
     
     
         5 . The system of  claim 3 , wherein the control system includes logic to set up a scribe pattern.  
     
     
         6 . The system of  claim 3 , wherein the stage includes a vacuum chuck.  
     
     
         7 . The system of  claim 3 , including a video system for viewing a substrate mounted on the stage.  
     
     
         8 . The system of  claim 3 , wherein the control system includes logic to set up parameters including pulse repetition rate, pulse energy and stage speed.  
     
     
         9 . The system of  claim 3 , wherein the laser comprises a Q-switched Nd:YAG laser.  
     
     
         10 . A system for scribing a sapphire substrate, comprising: 
 a laser generating pulses of laser energy in a wavelength less than about 560 nanometers, the laser comprising a Q-switched Nd:YVO 4  laser;    a stage adapted to support, and move, a sapphire substrate;    optics directing the pulses to impact a sapphire substrate mounted on the stage; and    a control system coupled to the solid state laser and the stage, the control system controlling the laser and stage, and causing the pulses to impact the sapphire substrate having a peak power density of about 10 GW/cm 2  or less at a repetition rate of greater than 5 kHz in a scribe pattern at a rate of motion causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate.    
     
     
         11 . The system of  claim 10 , wherein the laser comprises a diode pumped, Q-switched Nd:YVO 4  laser operating at a third harmonic wavelength of about 355 nanometers.  
     
     
         12 . The system of  claim 10 , wherein the laser comprises a diode pumped, Q-switched Nd:YAG laser operating at a third harmonic wavelength of about 355 nanometers.  
     
     
         13 . The system of  claim 10 , wherein the spot size is less than 15 microns.  
     
     
         14 . The system of  claim 10 , wherein the control system controls a rate of motion of the stage, causing overlap of successive pulses, wherein the overlap is in a range from 50 to 99 percent.  
     
     
         15 . The system of  claim 10 , wherein the pulse rate is greater than 50 kHz.  
     
     
         16 . The system of  claim 10 , wherein said energy density is between about 10 and 100 joules per square centimeter, and the spot size is about 20 microns or less.  
     
     
         17 . The system of  claim 10 , wherein the sapphire substrate has a thickness, and the control system is configured to cause the scribe lines to be cut to a depth of more than about one half said thickness.  
     
     
         18 . The system of  claim 10 , wherein the sapphire substrate has a thickness, and the control system is configured to cause the scribe lines to be cut to a predetermined depth.  
     
     
         19 . The system of  claim 10 , including optics to linearly polarize the pulses.  
     
     
         20 . The system of  claim 10 , including optics to adjust polarization of the pulses.  
     
     
         21 . A system for scribing a sapphire substrate, comprising: 
 a Q-switched, solid state laser generating pulses of laser energy in a wavelength between about 150 and 560 nanometers;    a stage adapted to support, and move, a sapphire substrate;    optics directing the pulses to impact a sapphire substrate mounted on the stage;    an edge detection system which detects edges of a substrate mounting on the stage during movement of the stage, preventing said pulses from being directed off the substrate; and    a control system coupled to the solid state laser, the stage and the edge detection system, the control system controlling the laser and stage, and responsive to the edge detection system, and causing the pulses to impact the sapphire substrate having a peak power density of about 10 GW/cm 2  or less at a repetition rate of greater than 10 kHz, in a scribe pattern at a rate of motion causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate.    
     
     
         22 . The system of  claim 21 , including a debris exhaust system.  
     
     
         23 . The system of  claim 21 , wherein the control system includes logic to set up a scribe pattern.  
     
     
         24 . The system of  claim 21 , wherein the stage includes a vacuum chuck.  
     
     
         25 . The system of  claim 21 , including a video system for viewing a substrate mounted on the stage.  
     
     
         26 . The system of  claim 21 , wherein the control system includes logic to set up parameters including pulse repetition rate, pulse energy and stage speed.  
     
     
         27 . The system of  claim 21 , wherein the laser comprises a Q-switched Nd:YAG laser.  
     
     
         28 . The system of  claim 21 , wherein the laser comprises a Q-switched Nd:YVO 4  laser.  
     
     
         29 . The system of  claim 21 , wherein the laser comprises a diode pumped, Q-switched Nd:YAG laser operating at a third harmonic wavelength of about 355 nanometers.  
     
     
         30 . The system of  claim 21 , wherein the laser comprises a diode pumped, Q-switched Nd:YVO 4  laser operating at a third harmonic wavelength of about 355 nanometers.  
     
     
         31 . The system of  claim 21 , wherein the spot size is less than 15 microns.  
     
     
         32 . The system of  claim 21 , wherein the overlap is in a range from 50 to 99 percent.  
     
     
         33 . The system of  claim 21 , wherein the pulse rate is greater than 50 kHz.  
     
     
         34 . The system of  claim 21 , wherein said energy density is between about 10 and 100 joules per square centimeter, and the spot size is about 20 microns or less.  
     
     
         35 . The system of  claim 21 , wherein the sapphire substrate has a thickness, and control system is configured to cause the scribe lines to be cut to a depth of more than about one half said thickness.  
     
     
         36 . The system of  claim 21 , wherein the sapphire substrate has a thickness, and the control system is configured to cause the scribe lines to be cut to a predetermined depth.  
     
     
         37 . The system of  claim 21 , including optics to linearly polarize the pulses.  
     
     
         38 . The system of  claim 21 , including optics to adjust polarization of the pulses.  
     
     
         39 . The system of  claim 21 , wherein the control system causing the pulses to impact the sapphire substrate has a peak power density of about 10 GW/cm 2  or less.  
     
     
         40 . The system of  claim 21 , wherein the control system causing the pulses to impact the sapphire substrate has a peak power density of about 10 GW/cm 2  or less.  
     
     
         41 . A system for scribing a sapphire substrate, comprising: 
 a laser generating pulses of laser energy in a wavelength less than about 560 nanometers, the laser comprising a Q-switched Nd:YVO 4  laser;    a stage adapted to support, and move, a sapphire substrate;    optics directing the pulses to impact the sapphire substrate mounted on the stage;    an edge detection system which detects edges of a substrate mounting on the stage during movement of the stage, preventing said pulses from being directed off the substrate; and    a control system coupled to the solid state laser and the stage, the control system controlling the laser and stage, and causing the pulses to impact the sapphire substrate having a peak power density of about 10 GW/cm 2  or less at a repetition rate of greater than 10 kHz in a scribe pattern at a rate of motion of 5.0 mm/sec or higher causing overlap of successive pulses sufficient to cut scribe lines in the sapphire substrate.