Low temperature reaction bonding
AssigneeAlliedSignal Inc.
InventorsGeorge G. Goetz, Warren M. Dawson
Life of this patent
Estimating the term…
Abstract
A method for reaction bonding surfaces at low temperatures in which polished and cleaned surfaces are bombarded with a mixture of oxygen and fluorine ions to produce activated surfaces. The activated surfaces are then cleaned to remove particulates, then contacted at room temperature to affect a reaction bond therebetween. The bond energy of the reaction bonded surfaces increase with time at room temperature. The rate at which the bond energy of the reaction bonded surfaces increases may be enhanced by moderate heating at a low temperature below a temperature which would be detrimental to any part of the reaction bonded structure. A satisfactory bond energy for silicon wafers can be achieved in four hours at room temperature and in less than 10 minutes at 50.degree. C.
Claims19
A method for reaction bonding solid surfaces at a low temperature comprising the steps of:
- polishing each solid surface to be reaction bonded to have a maximum roughness of the order of atomic dimensions to produce polished surfaces;
- cleaning each of said polished surfaces to remove contaminants and particulates to produce cleaned surfaces;
- ion bombarding said cleaned surfaces with a mixture of oxygen and fluorine ions having an energies preselected to produce activated surfaces;
- and
- placing said activated surfaces in physical contact with each other at room temperature to reaction bond said activated surfaces.
A method for reaction bonding two surfaces at a low temperature comprising the steps of:
- polishing each of the two surfaces to be reaction bonded to have a roughness less:
- than a predetermined roughness;
- cleaning said surfaces to remove contaminants and particulates which would interfere with reaction bonding;
- placing said cleaned surfaces in an ion bombardment chamber having a reduced pressure oxygen atmosphere containing a predetermined quantity of a gas containing fluorine;
- ionizing said oxygen and said gas containing fluorine to produce oxygen and fluorine ions;
- accelerating said oxygen ions and said fluorine ions toward said surfaces with a predetermined energy;
- bombarding said surfaces with said oxygen and fluorine ions having energies selected to produce activated surfaces;
- and
- contacting said activated surfaces at room temperature to produce a reaction bond therebetween.
A method for increasing the reaction bond energy between two surfaces at a low temperature comprising the steps of:
- polishing each of the two surfaces to be reaction bonded to have a roughness less than a predetermined roughness;
- cleaning said two surfaces to remove contaminants and particulates which would interfere with reaction bonding;
- placing said cleaned surfaces in an ion bombardment chamber having a reduced pressure atmosphere of oxygen and a gas containing fluorine;
- ionizing said oxygen and gas containing fluorine to generate oxygen and fluorine ions;
- accelerating said oxygen and fluorine ions toward said cleaned surfaces with a predetermined energy;
- bombarding said cleaned surfaces with said oxygen and fluorine ions to produce activated surfaces;
- reaction bonding said activated surfaces;
- and
- storing said reaction bonded surfaces for a preselected time at said low temperature to increase the bond energy of said reaction bonded activated surfaces to a desired minimum value.
Dependencies are inferred from the claim text.