Systems and methods for laser dicing of bonded structures

A laser dicing system for dicing a bonded structure, comprising:

• a laser source configured to generate a series of pulsed lasers;
• an optical module coupled to the laser source, configured to provide a series of focused laser spots;
• and
• a controller coupled to the laser source and the optical module, configured to:
• determine relative positions between a series of ablation structures and a bonding interface of the bonded structure, comprising determining positional relationships of one or more first cuttings and one or more second cuttings with respect to the bonding interface between a first wafer and a second wafer, the positional relationships comprising a first cutting depth between the one or more first cuttings and the bonding interface and a second cutting depth between the one or more second cuttings and the bonding interface, and the series of ablation structures comprising the one or more first cuttings in the first wafer and the one or more second cuttings in the second wafer, and each of the one or more first cuttings corresponding to one of the one or more second cuttings;
• determine at least one of one or more focal planes or a depth of focus of a laser beam based on the relative positions between the series of ablation structures and the bonding interface, comprising one of:
• determining a first focal plane nominally coincident with a first cutting level of the one or more first cuttings and a second focal plane nominally coincident with a second cutting level of the one or more second cuttings based on the bonding interface, the first cutting depth, and the second cutting depth;
• and
• determining a third focal plane nominally coincident with the bonding interface and the depth of focus covering the first cutting level and the second cutting level based on the first cutting depth and the second cutting depth;
• and
• move the series of focused laser spots in the bonded structure to form the series of ablation structures in the first wafer and the second wafer in the bonded structure.

A method for dicing a bonded structure, comprising:

• determining, by a controller, a scan pattern for forming a series of ablation structures in the bonded structure, the series of ablation structures comprising one or more first cuttings in a first wafer and one or more second cuttings, each corresponding to one of the one or more first cuttings, in a second wafer, and the series of ablation structures being arranged between a first part and a second part of the bonded structure;
• determining, by the controller, a first positional relationship of the one or more first cuttings with respect to a bonding interface and a second positional relationship of the one or more second cuttings with respect to the bonding interface, the bonding interface being positioned between the first wafer and the second wafer, the first positional relationship comprising a first cutting depth between the one or more first cuttings and the bonding interface, and the second positional relationship comprising a second cutting depth between the one or more second cuttings and the bonding interface;
• determining, by the controller, at least one of one or more focal planes or a depth of focus of a laser beam based on the first positional relationship and the second positional relationship, comprising one of:
• determining a first focal plane nominally coincident with a first cutting level of the one or more first cuttings and a second focal plane nominally coincident with a second cutting level of the one or more second cuttings based on the bonding interface, the first cutting depth, and the second cutting depth;
• and
• determining a third focal plane nominally coincident with the bonding interface and the depth of focus covering the first cutting level and the second cutting level based on the first cutting depth and the second cutting depth;
• generating, by a laser source, the laser beam, the laser beam having a series of pulsed lasers;
• and
• moving, by the controller, the laser beam in the bonded structure according to the scan pattern to form the series of ablation structures in the bonded structure, wherein the first part and the second part of the bonded structure are separated along the series of ablation structures.