Method and system for ion beam delayering of a sample and control thereof
There is provided a method, system and computer program product to delayer a layer of a sample, the layer comprising one or more materials, in an ion beam mill by adjusting one or more operating parameters of the ion beam mill and selectively removing each of the one or more materials at their respective predetermined rates. There is also provided a method and system for obtaining rate of removal of a material from a sample in an ion beam mill.
1. A method of reverse engineering a sample using an ion beam mill, the method comprising the steps of:
identifying a plurality of materials in an exposed surface of the sample and a set of two or more predetermined operational characteristics that correspond with a substantially identical ion beam mill removal rate for each of said materials;
operating the ion beam mill in accordance with the identified set of two or more predetermined operational characteristics to simultaneously remove, using an ion beam from the ion beam mill, each of the plurality of materials at said substantially identical ion beam mill removal rate to remove a substantially planar layer of substantially constant thickness from the exposed surface of the sample;
acquiring surface data from a newly exposed surface of the sample; and
repeating the identifying, operating and acquiring steps for at least one more layer, the acquired surface data for reverse engineering at least a portion of the sample,
wherein the predetermined operational characteristics are any of the following: angle of sample-to-ion beam direction, ion beam size, ion type, sample stage temperature, chamber base pressure, chamber cross-over pressure, chamber process pressure, sample stage linear location, sample stage angle, sample stage rotation speed, ion source accelerator voltage, ion source accelerator current, ion source beam voltage, ion source beam current, ion source extractor grid configuration, ion source extractor grid material, ion source RF power, extraction voltage, plasma bridge neutralizer (PBN) cathode voltage, PBN emission current, PBN gas flow, ion source type, ion source gas flow rate, chamber background gas type, chamber background gas flow rate, and sidewall angle.
2. The method of claim 1 , further comprising the step:
producing hierarchical circuit schematics using the acquired surface data.
3. The method of claim 1 , wherein the ion beam operates in the presence of a reactive gas.
4. The method of claim 1 , wherein the ion beam operates in the presence of a non-reactive gas.
5. The method of claim 3 , wherein the predetermined operational characteristics further comprise: type of reactive gas, and flow rate of reactive gas.
6. A method of delayering a sample using an ion beam mill, the method comprising:
identifying a plurality of materials in an exposed surface of the sample and a set of two or more predetermined operational characteristics that correspond with a substantially identical ion beam mill removal rate for each of said materials;
operating the ion beam mill in accordance with the identified set of two or more predetermined operational characteristics to simultaneously remove, using an ion beam from the ion beam mill, each of the plurality of materials at said substantially identical ion beam mill removal rate to remove a substantially planar layer of substantially constant thickness from said exposed surface of the sample;
acquiring surface data from a newly exposed surface of the sample;
repeating said operating and acquiring steps until a predetermined number of one or more successive layers have been removed; and
reverse engineering said sample by producing hierarchical circuit schematics using said acquired surface data,
wherein the predetermined operational characteristics are any of the following: angle of sample-to-ion beam direction, ion beam size, ion type, sample stage temperature, chamber base pressure, chamber cross-over pressure, chamber process pressure, sample stage linear location, sample stage angle, sample stage rotation speed, ion source accelerator voltage, ion source accelerator current, ion source beam voltage, ion source beam current, ion source extractor grid configuration, ion source extractor grid material, ion source RF power, extraction voltage, plasma bridge neutralizer (PBN) cathode voltage, PBN emission current, PBN gas flow, ion source type, ion source gas flow rate, chamber background gas type, chamber background gas flow rate, and sidewall angle.
7. The method of claim 6 , wherein the ion beam operates in the presence of a reactive gas.
8. The method of claim 6 , wherein the ion beam operates in the presence of a non-reactive gas.
9. The method of claim 7 , wherein the predetermined operational characteristics further comprise: type of reactive gas, and flow rate of reactive gas.