Systems and methods for bidirectional device fabrication
AssigneeIdeal Power Inc.
InventorsRichard A. Blanchard, William C. Alexander
Life of this patent
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Abstract
Methods and systems for double-sided semiconductor device fabrication. Devices having multiple leads on each surface can be fabricated using a high-temperature-resistant handle wafer and a medium-temperature-resistant handle wafer. Dopants can be introduced on both sides shortly before a single long high-temperature diffusion step diffuses all dopants to approximately equal depths on both sides. All high-temperature processing occurs with no handle wafer or with a high-temperature handle wafer attached. Once a medium-temperature handle wafer is attached, no high-temperature processing steps occur. High temperatures can be considered to be those which can result in damage to the device in the presence of aluminum-based metallizations.
Claims19
A method of fabricating a two-sided semiconductor device which has patterned current-carrying contact areas on both faces of a semiconductor wafer, comprising, in any order except as specified:
- a) introducing dopants in two respective patterns into a first face of the wafer;
- and then
- b) attaching a first handle wafer to the first face of the wafer;
- c) introducing dopants in two respective patterns into a second face of the wafer;
- d) heating the wafer, to thereby diffuse and activate the dopants in both said first and second faces of the wafer;
- e) forming patterned metallization on the second face of the wafer, and then attaching a second handle wafer over the patterned metallization;
- f) removing the first handle wafer, and then forming additional patterned metallization on the first face of the wafer;
- and then
- g) removing the second handle wafer, and completing fabrication of a two-sided semiconductor device.
A method of fabricating a two-sided semiconductor device which has patterned current-carrying contact areas on both faces of a semiconductor wafer, comprising, in any order except as specified:
- a) introducing dopants in a pattern into a first face of the wafer;
- and then
- b) attaching a first handle wafer to the first face of the wafer;
- c) introducing dopants in a pattern into a second face of the wafer;
- d) heating the wafer, to thereby diffuse and activate the dopants in both said first and second faces of the wafer;
- e) forming patterned metallization on the second face of the wafer, and then attaching a second handle wafer, which has a different composition from the first handle wafer, over the patterned metallization;
- f) removing the first handle wafer, and then forming additional patterned metallization on the first face of the wafer;
- and then
- g) removing the second handle wafer, and completing fabrication of a two-sided semiconductor device.
A method of fabricating a two-sided power semiconductor device which has both patterned current-carrying connections and also control terminal connections on both faces of a semiconductor wafer, comprising, in any order except as specified:
- a) introducing both p-type and n-type dopants in a pattern, and not overall, into a first face of the wafer;
- b) attaching a first handle wafer to the first face of the wafer;
- c) introducing both p-type and n-type dopants in a pattern, and not overall, into a second face of the wafer;
- d) heating the wafer, to thereby diffuse and activate the dopants in both said first and second faces of the wafer;
- e) forming patterned metallization on the second face of the wafer, and then attaching a second handle wafer over the patterned metallization;
- f) removing the first handle wafer, and then forming additional patterned metallization on the first face of the wafer;
- and then
- g) removing the second handle wafer, and completing fabrication of a two-sided semiconductor device.
Dependencies are inferred from the claim text.