Low-temperature bonding process

摘要

The invention relates to a process for assembling a first element that includes at least one first wafer, substrate or at least one chip, and a second element of at least one second wafer or substrate, involving the formation of a surface layer, known as the bonding layer, on each substrate, at least one of these bonding layers being formed at a temperature less than or equal to 300° C.; conducting a first annealing, known as degassing annealing, of the bonding layers, before assembly, at least partly at a temperature at least equal to the subsequent bonding interface strengthening temperature but below 450° C.; forming an assembling of the substrates by bringing into contact the exposed surfaces of the bonding layers, and conducting an annealing of the assembled structure at a bonding interface strengthening temperature below 450° C.

主权项

1. A method for bonding two surfaces at low temperatures comprising:
forming at a low temperature a first bonding layer on a first substrate and a second bonding layer on a second substrate, wherein at least one of the first substrate or the second substrate comprises one or more components, micro-components or circuits, wherein the first bonding layer and the second bonding layer each have an exposed surface, and the formation of each bonding layer is done at a low temperature that is less than or equal to 300° C.; conducting a first annealing of the first and second bonding layers on the first and second substrates for a first annealing time period, wherein the first annealing is conducted up to and at an annealing temperature that is higher than the low temperature of formation of each bonding layer and is at least 350° C. but less than 450° C. and for a time which does not deleteriously affect the components, micro-components or circuits; assembling the annealed first and second substrates to form a structure by bringing into contact the exposed surfaces of the first bonding layer and the second bonding layer; and conducting a second annealing of the first and second bonding layers of the bonded first and second substrates after assembling the structure, with the second annealing conducted at a second temperature of at least 350° C. and lower than or at most equal to the first annealing temperature, wherein the second annealing is conducted at a temperature and time which does not deleteriously affect the components, micro-components or circuits, and wherein the annealings provide a bonding interface between the substrates that has a bonding energy of at least 4 J/m2.