Methods and systems for processing a device, methods and systems for modeling same and the device
View Patent ↗A method and system for locally processing a predetermined microstructure formed on a substrate without causing undesirable changes in electrical or physical characteristics of the substrate or other structures formed on the substrate are provided. The method includes providing information based on a model of laser pulse interactions with the predetermined microstructure, the substrate and the other structures. At least one characteristic of at least one pulse is determined based on the information. A pulsed laser beam is generated including the at least one pulse. The method further includes irradiating the at least one pulse having the at least one determined characteristic into a spot on the predetermined microstructure. The at least one determined characteristic and other characteristics of the at least one pulse are sufficient to locally process the predetermined microstructure without causing the undesirable changes.
1. A method of laser processing a multi-level, multi-material device including a substrate, a microstructure and a multi-layer stack, the stack having at least two inner dielectric layers which separate the microstructure from the substrate, the method comprising:
generating a pulsed laser beam having a predetermined wavelength less than an absorption edge of the substrate, the substrate having a relatively high absorption coefficient at the predetermined wavelength and the stack having a low absorption coefficient at the predetermined wavelength and including at least one laser pulse wherein at least reflections of the laser beam by the layers of the stack substantially reduce pulse energy density at the substrate relative to at least one other wavelength and wherein the at least one laser pulse has a duration of greater than a few picoseconds to several nanoseconds; and
processing the microstructure with the at least one laser pulse wherein pulse energy density at the microstructure is sufficient to remove the microstructure while avoiding damage to the substrate and the inner layers of the stack.
2. The method of claim 1 wherein the predetermined wavelength is a near UV wavelength above the absorption edge of the stack.
3. The method of claim 1 wherein the substrate is a silicon substrate and the microstructure is a metal link.
4. The method of claim 3 wherein the metal of the link comprises copper.
5. The method of claim 1 wherein pulse energy density at the substrate is further reduced with a predetermined characteristic of the at least one pulse.
6. The method of claim 5 wherein the predetermined characteristic is based on a model of laser pulse material interaction.
7. The method of claim 6 wherein the model is a thermal model.
8. The method of claim 6 wherein the model is a multi-parameter model.
9. The method of claim 1 wherein the step of generating includes the step of shifting the wavelength of the laser beam from a first wavelength to the predetermined wavelength wherein the predetermined wavelength is based on material characteristics comprising at least one of: (1) coupling characteristics of the microstructure, (2) multi-layer interference, and (3) substrate reflectivity.
10. The method of claim 1 wherein the materials of the at least two inner dielectric layers are different.
11. The method of claim 2 wherein the predetermined wavelength is about 0.35 um.
12. The method of claim 5 wherein the predetermined characteristic is a spatial characteristic.