Dual laser cutting of wafers

A method for singulating a semiconductor substrate having a coating layer, the method comprising the steps of:

• (a) aiming a first and a second laser beam over a top surface of the substrate;
• (b) forming a first set of scribe lines in a first direction in the layer by scanning the first laser beam across the layer, the first laser beam removing at least a portion of the layer;
• (c) forming a second set of scribe lines in a second direction in the layer by scanning the first laser beam across the layer and removing at least a portion of the layer with the first laser beam;
• (d) cutting through the substrate along the second set of scribe lines with the second laser beam to form a respective first set of kerfs;
• and
• (e) cutting through the substrate along the first set of scribe lines with the second laser beam to form a respective second set of kerfs.

A method for singulating a semiconductor substrate comprising the steps of:

• (a) aiming a first laser beam at a layer placed over a top surface of the substrate, the layer having a first absorption coefficient relative to a wavelength of the laser beam;
• (b) absorbing energy from the first laser beam into the layer based on the first absorption coefficient;
• (c) forming a first set of scribe lines in a first direction in the layer by scanning the first laser beam across the layer, the first laser beam removing at least a portion of the layer;
• (d) forming a second set of scribe lines in a second direction in the layer by scanning the first laser beam across the layer and removing at least a portion of the layer with the first laser beam;
• (e) aiming a second laser beam at the second set of scribe lines and cutting through the substrate along the first set of scribe lines with the second laser beam to form a respective first set of kerfs;
• and
• (f) aiming a second laser beam at the first set of scribe lines and cutting through the substrate along the second set of scribe lines with the second laser beam to form a respective second set of kerfs,
• wherein the substrate has a second absorption coefficient relative to the wavelength of the first laser beam, the second absorption coefficient less than the first absorption coefficient by about an order of magnitude.

A method for singulating a semiconductor substrate comprising the steps of:

• (a) aiming a first laser beam at a layer placed over a top surface of the substrate;
• (b) absorbing energy from the first laser beam into only the layer;
• (c) forming a first set of scribe lines in a first direction in the layer by scanning the first laser beam across the layer, the first laser beam removing at least a portion of the layer;
• (d) forming a second set of scribe lines in a second direction in the layer by scanning the first laser beam across the layer and removing at least a portion of the layer with the first laser beam, the second direction substantially orthogonal to the first direction;
• (e) aiming a second laser beam at the top surface of the substrate;
• (f) cutting through the substrate along the second set of scribe lines with the second laser beam;
• and
• (g) cutting through the substrate along the first set of scribe lines with the second laser beam,
• wherein the layer has a first absorption coefficient and the substrate has a second absorption coefficient relative to a wavelength from the laser beam, the first absorption coefficient greater than the second absorption coefficient.

A method for singulating a semiconductor substrate using a plurality of lasers, the method comprising the steps of:

• (a) aiming a first laser of the plurality of lasers at a layer placed over a top surface of the substrate;
• (b) absorbing energy from the first laser into the layer;
• (c) forming a first set of scribe lines in a first direction in the layer by scanning the first laser across the layer, the first laser removing at least a portion of the layer;
• (d) forming a second set of scribe lines in a second direction in the layer by scanning the first laser across the layer and removing at least a portion of the layer with the first laser, the second direction substantially orthogonal to the first direction;
• (e) aiming a second laser of the plurality of lasers at the top surface of the substrate;
• (f) cutting a first set of kerfs in the substrate with the second laser along the second set of scribe lines;
• and
• (g) cutting a second set of kerfs in the substrate with the second laser along the first set of scribe lines,
• wherein the layer has a first absorption coefficient and the substrate has a second absorption coefficient relative to a wavelength of the first laser, the first absorption coefficient greater than the second absorption coefficient by about an order of an order of magnitude, and the first set of kerfs and the second set of kerfs form a plurality of dice from the substrate.

A method for singulating a semiconductor substrate using a plurality of lasers, the method comprising the steps of:

• (a) aiming the plurality of lasers over a top surface of the substrate;
• (b) absorbing energy from a first laser of the plurality of lasers into the layer;
• (c) forming a first scribe line in a first direction in the layer by scanning the first laser across the layer, the laser removing at least a portion of the layer;
• (d) cutting a first kerf in the substrate with a second laser of the plurality of lasers along the first scribe line;
• (e) forming a further first scribe line in the first direction in the layer over the substrate, the further scribe line substantially parallel to the first scribe line;
• (f) cutting a further first kerf in the substrate with the second laser along the further first scribe line;
• (g) repeating steps (e) and (f) in the first direction until the entire substrate is scribed and cut;
• (h) forming a second scribe line in a second direction in the layer over the substrate by scanning the first laser across the layer and removing at least a portion of the layer, the second direction substantially orthogonal to the first direction;
• (i) cutting a second kerf in the substrate with the second laser along the second scribe line;
• (j) forming a further second scribe line in the second direction in the layer over the substrate, the further second scribe line substantially parallel to the second scribe line;
• (k) cutting a further second kerf in the substrate with the second laser along the further second scribe line;
• and
• (l) repeating steps (j) and (k) in the second direction until the entire substrate is scribed and cut,
• wherein the layer has a first absorption coefficient and the substrate has a second absorption coefficient relative to a wavelength of the laser beam, the first absorption coefficient greater than the second absorption coefficient by about an order of magnitude, and the first kerf, the further first kerfs, the second kerf and the further second kerfs form a plurality of dice from the substrate.

A method for singulating a semiconductor substrate using a plurality of lasers, the method comprising the steps of:

• (a) aiming a first laser at a layer placed over a top surface of the substrate;
• (b) forming a first set of scribe lines in a first direction in the layer by scanning the first laser across the layer, the first laser removing at least a portion of the layer;
• (c) aiming a second laser at the top surface of the substrate;
• (d) cutting a first set of kerfs in the substrate with the second laser along the first set of scribe lines;
• (e) forming a second set of scribe lines in a second direction in the layer by scanning the first laser across the layer and removing at least a portion of the layer with the first laser;
• (f) cutting a second set of kerfs in the substrate with the second laser along the second set of scribe lines,
• wherein the layer has a first absorption coefficient and the substrate has a second absorption coefficient relative to a wavelength of the laser beam, the first absorption coefficient greater than the second absorption coefficient by about an order of an order of magnitude, and the first set of kerfs and the second set of kerfs form a plurality of dice from the substrate.

An apparatus for singulating a semiconductor substrate having a coating layer thereon, the apparatus comprising:

• a first laser placed over the coating layer of the substrate, the coating layer having a first absorption coefficient relative to a wavelength of the first laser and the semiconductor substrate having a second absorption coefficient less than the first absorption coefficient;
• and
• a second laser placed over a surface of the substrate,
• wherein energy from the first laser beam is absorbed into the coating layer based on a first absorption coefficient to form at least one scribe line therein, and the second laser cuts through the substrate along the at least one scribe line.