Level realignment following an epitaxy step
View Patent ↗The invention relates to inter-level realignment after a stage of epitaxy on a face ( 31 ) of a substrate ( 30 ), comprising the production of at least one initial guide mark ( 32 ) on the face of the substrate, this initial guide mark being designed so as to be transferred, during epitaxy, onto the surface of the epitaxied layer ( 36 ). The initial guide mark ( 32 ) is produced in such a way that, during epitaxy, its edges create growth defects that propagate as far as the surface of the epitaxied layer ( 36 ) to provide a transferred guide mark ( 37 ) on the surface of the epitaxied layer ( 36 ) reproducing the shape of the initial guide mark ( 32 ) and in alignment with the initial guide mark.
1. A method enabling realignment between levels after a stage of epitaxy on a face of a substrate, comprising the production of at least one initial guide mark on said substrate face, the initial guide mark being designed so as to be transferred, during epitaxy, onto a surface of the epitaxied layer, the initial guide mark being produced in such a manner that, during epitaxy, its edges create growth defects that propagate as far as the surface of the epitaxied layer to provide a transferred guide mark on the epitaxied layer reproducing a shape of the initial guide mark and in alignment with the initial guide mark, wherein the production of the initial guide mark includes the formation of a plate comprising a stack of at least one layer of material not allowing development of epitaxy, formed on the substrate face, and of a layer of material permitting development of epitaxy.
2. The method according to claim 1 , wherein the plate is formed by stages of deposit and engraving of layers.
3. The method according to claim 1 , wherein the layer of material not allowing development of epitaxy is a layer of dielectric material.
4. The method according to claim 1 , wherein said face of the substrate is a face allowing epitaxy of a semiconductor material.
5. The method according to claim 1 , wherein said face of the substrate is a semiconductor material.
6. The method according to claim 3 , wherein said face of the substrate is in monocrystalline silicon, the layer of material of the initial guide mark allowing development of epitaxy being in polycrystalline silicon, the edges of the guide mark being aligned with the crystalline axes of the monocrystalline silicon of the substrate.
7. The method according to claim 6 , wherein the formation of the plate comprises, for obtaining the material not allowing development of epitaxy, the formation of a layer of silicon oxide and/or the formation of a layer of silicon nitride.
8. A substrate intended for the production of an epitaxy on one of its faces, comprising at least one initial guide mark designed to obtain, after the epitaxy stage, a transferred guide mark on a surface of the epitaxied layer, the initial guide mark having edges able to create growth defects during epitaxy, which propagate as far as the surface of the epitaxied layer to provide, on the surface of the epitaxied layer, the transferred guide mark that reproduces a shape of the initial guide mark and is in alignment with the initial guide mark, wherein the initial guide mark comprises a stack including at least one layer of material not allowing development of epitaxy, formed on the substrate face, and a layer of epitaxial material.
9. The substrate according to claim 8 , wherein the layer of material not allowing development of epitaxy is a layer of dielectric material.
10. The substrate according to claim 8 , wherein said face of the substrate is a face allowing epitaxy of a semiconductor material.
11. The substrate according to claim 8 , wherein said face of the substrate is a semiconductor material.
12. The substrate according to claim 8 , wherein said face of the substrate is in monocrystalline silicon, the layer of epitaxial material of the initial guide mark being in polycrystalline silicon, the edges of the guide mark being aligned with the crystalline axes of the monocrystalline silicon of the substrate.
13. The substrate according to claim 12 , wherein the layer of material not allowing development of epitaxy is a layer of silicon oxide or a layer of silicon nitride.