Process for fabricating a heterostructure with minimized stress
AssigneeSoitec
InventorAlexandre Vaufredaz
Life of this patent
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Abstract
A process for fabricating a heterostructure by bonding a first wafer to a second wafer, with the first wafer having a thermal expansion coefficient that is lower than the thermal expansion coefficient of the second wafer, and conducting at least one bond-strengthening annealing step. After the bonding step and before the bond-strengthening annealing step, at least one trimming step is conducted in which the first wafer is at least partially trimmed.
Claims18
A process for fabricating a heterostructure comprising:
- bonding a first wafer to a second wafer, wherein the first wafer has a thermal expansion coefficient that is lower than the thermal expansion coefficient of the second wafer, and the first wafer has an edge;
- conducting a first trimming step in which an annular portion at the edge of the first wafer is at least partially reduced in thickness;
- and
- conducting at least one bond-strengthening annealing step after the first trimming step;
- wherein the first trimming step is conducted after the bonding step and before thinning of the first wafer and remaining annular portion.
A process for fabricating a heterostructure which comprises:
- bonding a first wafer to a second wafer, wherein the first wafer has a thermal expansion coefficient that is lower than the thermal expansion coefficient of the second wafer, and the first wafer has an edge;
- conducting a first trimming step in which an annular portion at the edge of the first wafer is at least partially reduced in thickness;
- conducting at least one bond-strengthening annealing step;
- conducting a second trimming step;
- wherein the first trimming step is carried out after the bonding and before a first bond-strengthening annealing step, and the second trimming step is conducted after the first bond-strengthening annealing step but before a second bond-strengthening annealing step.
A process for forming a transferred layer corresponding to a portion of a first wafer in a heterostructure, comprising:
- forming a heterostructure by bonding first and second wafers together wherein the second wafer has a thermal expansion coefficient that is higher than the thermal expansion coefficient of the first wafer;
- trimming only an annular portion of an edge of the first wafer so that the edge is at least partially reduced in thickness;
- and
- conducting at least one bond-strengthening annealing step on the heterostructure after the first trimming step;
- wherein the trimming is conducted after the bonding but before a thinning step of the first wafer and remaining annular portion.
Dependencies are inferred from the claim text.