Image sensor of curved surface
A method for manufacturing an image sensor, including the steps of: forming elementary structures of an image sensor on the first surface of a semiconductor substrate; installing a layer on the first surface; defining trenches in the layer, the trenches forming a pattern in the layer; and installing, on a hollow curved substrate, the obtained device on the free surface side of the layer, the pattern being selected according to the shape of the support surface.
1. A method for manufacturing an image sensor, the method comprising:
forming elementary structures of an image sensor on the first surface of a semiconductor substrate;
forming a layer over said first surface of the semiconductor substrate;
defining trenches in the layer, said trenches forming a pattern in the layer; and
conforming the layer to a concave-shaped surface of a support by placing the layer with the trenches in the concave-shaped surface of the support, wherein the trenches prevent the layer from fracturing when conforming to the concave-shape of the surface of the support.
2. The method of claim 1 , wherein the pattern is selected to provide a fracture-free deformation of the layer during the conforming step.
3. The method of claim 1 , wherein defining the trenches in the layer is followed by filling of said trenches with a material having a high resistance to deformation.
4. The method of claim 1 , wherein conforming said layer is followed by thinning said layer.
5. The method of claim 1 , wherein the trenches extend through the layer.
6. The method of claim 1 , wherein the trenches extend into the layer perpendicularly to a surface of the layer.
7. The method of claim 1 , further comprising forming of an interconnection stack on the first surface of the semiconductor substrate before conforming the layer to a concave-shaped surface of a support.
8. The method of claim 1 , wherein the support has a hollow spherical cap shape.
9. The method of claim 8 , wherein the pattern forms, at a surface of the layer, concentric strips centered on a center of the elementary structures, separate strips that extend on radiuses of a circle having its center corresponding to the center of the elementary structures, rectangles regularly distributed on the surface of a circle having its center located in front of the center of the elementary structures, or a generally circular shape having rectangles of the layer left therein.
10. The method of claim 1 , wherein the support is hollow, in the shape of a cylinder portion with a circular base.
11. The method of claim 10 , wherein the pattern of the trenches forms, at the surface of the layer, parallel strips.
12. The method of claim 1 , wherein the support has an inner disk in a shape of a spherical cap and an outer strip in a shape of a truncated cone.
13. The method of claim 12 , wherein the pattern forms, at a surface of the layer, an inner disk within which is defined a regular rosette and an external strip in which are defined substantially triangular shapes having one side formed of the external surface of the portions of the rosette defined in the inner disk, and having their two other sides extending until they meet on the circle defining the external contour of the external strip.
14. An image sensor, comprising:
a support having a hollow curved surface,
a stack that includes a layer having a plurality of trenches over a semiconductor substrate, the stack conforming to a concave-shaped surface of a support, said layer being in contact with said concave-shaped surface of said support, wherein the trenches prevent the layer from fracturing when conforming to the concave-shape surface of the support.
15. The image sensor of claim 14 , wherein the trenches extend through the layer.
16. The image sensor of claim 14 , wherein the trenches in the layer are filled with an insulating material.