Method for gettering noble metals from mineral acid solution
AssigneeMicron Technology, Inc.
InventorsTroy Sorensen, Eric Grieger
Life of this patent
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Abstract
Silicon is employed as a reducing agent in an acid bath to adsorb noble metals present as contaminants in the acid. In the manufacture of silicon devices for electronic memory and other devices, polonium-210 is adsorbed by silicon getters to reduce soft error rate attributable to alpha particle emissions from the radioactive polonium. The noble metals in addition to polonium which can be plated onto silicon using the disclosed method are gold, silver, platinum, copper, palladium, mercury, selenium and bismuth.
Claims8
A method for removing a radioactive contaminant from a fluid, comprising the following steps:
- a) providing contact between silicon and the fluid;
- b) allowing sufficient time for the radioactive contaminant to adhere to the silicon;
- c) maintaining a temperature of the fluid within a range of temperatures between 145 and 150 degrees centigrade during said time defined by said step of allowing;
- and
- d) separating the fluid and the silicon having the adhered radioactive contaminant.
A method for removing a radioactive contaminant from an acidic solution, comprising the following steps:
- a) inserting silicon into a container in fluid contact with the acidic solution;
- b) heating the acidic solution to a temperature at which the silicon attracts the radioactive contaminant, said temperature falling within a range of temperatures between 145 and 150 degrees centigrade;
- and
- c) removing the silicon and the radioactive contaminant from the container.
A method for fabricating a semiconductor integrated circuit, comprising the following steps:
- a) providing a phosphoric acid solution containing polonium-210;
- b) heating said phosphoric acid solution to a temperature suitable for attracting the polonium-210 to silicon;
- and
- c) inserting silicon into said phosphoric acid solution;
- and
- d) heating said silicon to said temperature such that the polonium-210 is attracted to said silicon.
Dependencies are inferred from the claim text.