Method and apparatus for cutting devices from conductive substrates secured during cutting by vacuum pressure
AssigneeNew Wave Research
InventorKuo-Ching Liu
Life of this patent
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Abstract
A method and system for cutting a wafer comprising a conductive substrate attached to an array of integrated devices includes placing the wafer on a stage such as a movable X-Y stage including a vacuum chuck having a porous mounting surface, and securing the wafer during and after cutting by vacuum pressure through the pores. The wafer is cut by directing UV pulses of laser energy at the conductive substrate using a solid-state laser. An adhesive membrane can be attached to the separated die to remove them from the mounting surface, or the die can otherwise be removed after cutting from the wafer.
Claims36
A system for separating integrated devices from an array of integrated devices on a conductive substrate, comprising:
- a laser generating laser energy in a wavelength substantially absorbed by the conductive substrate;
- a stage adapted to support, and move, the conductive substrate, the stage including a vacuum chuck having a porous mounting surface adapted to secure the conductive substrate on the stage by suction through pores in the porous mounting surface;
- optics directing the laser energy to impact the conductive substrate secured 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 laser energy to impact the conductive substrate in a pattern at a rate of motion sufficient to cut kerfs substantially through the conductive substrate in the pattern.
A system for separating laser diodes from an array of laser diodes on a conductive substrate, comprising:
- a Q-switched, solid state laser generating pulses of laser energy in a wavelength between about 150 and 560 nanometers, pulse duration less than about 30 nanoseconds and a spot size of less than 25 microns, at a repetition rate of greater than 10 kHz;
- a stage adapted to support, and move, the conductive substrate, the stage including a vacuum chuck having a porous mounting surface adapted to secure the conductive substrate on the stage by suction through pores in the porous mounting surface;
- optics directing the pulses to impact the conductive substrate secured on the stage;
- an edge detection system which detects edges of the conductive substrate mounted on the stage during movement of the stage;
- 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 conductive substrate in a pattern at a rate of motion causing overlap of successive pulses sufficient to cut kerfs substantially through the conductive substrate.
Dependencies are inferred from the claim text.