| US 7,541,256 B2 | ||
| Method of fabricating back-illuminated imaging sensors using a bump bonding technique | ||
| Pradyumna Kumar Swain, Princeton, N.J. (US); Peter Levine, West Windsor, N.J. (US); Mahalingam Bhaskaran, Lawrenceville, N.J. (US); and Norman Goldsmith, East Brunswick, N.J. (US) | ||
| Assigned to Sarnoff Corporation, Princeton, N.J. (US) | ||
| Filed on Jul. 18, 2007, as Appl. No. 11/779,414. | ||
| Claims priority of provisional application 60/908436, filed on Mar. 28, 2007. | ||
| Prior Publication US 2008/0237762 A1, Oct. 02, 2008 | ||
| Int. Cl. H01L 21/76 (2006.01) | ||
| U.S. Cl. 438—401 [438/455; 257/797; 257/E23.179] | 19 Claims |
| 1. A method for fabricating a semiconductor device, comprising the steps of:
providing a substrate comprising:
an insulator layer, and
an epitaxial layer substantially overlying the insulator layer;
forming a plurality of alignment keys substantially overlying the epitaxial layer by:
printing key patterns on a top portion of the epitaxial layer,
etching the underlying epitaxial layer below the key patterns using a trench etch process until the etched away silicon is
stopped by the underlying insulator layer, and
filling the opened trenches with an electrically insulating material;
forming a plurality of bond pads substantially overlying the epitaxial layer;
fabricating a dielectric layer substantially overlying the epitaxial layer;
providing a handle wafer;
forming a plurality of conductive trenches in the handle wafer;
forming a plurality of conductive bumps on a first surface of the handle wafer substantially underlying the conductive trenches;
and
bonding the plurality of conductive bumps to the plurality of bond pads.
|