Back to results
US 9,355,853 B2Granted
Systems and methods for bidirectional device fabrication
AssigneeIdeal Power Inc.
InventorsRichard A. Blanchard, William C. Alexander
Life of this patent
Estimating the term…
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.
Claims20
A method of fabricating a semiconductor device, comprising:
- introducing first-conductivity-type dopants into first regions on a first face of a semiconductor mass;
- introducing second-conductivity-type dopants into second regions on said first face;
- attaching a high-temperature-resistant handle wafer to said first face;
- introducing first-conductivity-type dopants into third regions on a second face of said semiconductor mass which is parallel to said first face;
- introducing second-conductivity-type dopants into fourth regions on said second face;
- performing a high-temperature diffusion step;
- whereby said diffusion step diffuses the first-conductivity-type dopants in said first and third regions and the second-conductivity-type dopants in said second and fourth regions to corresponding desired depths in said semiconductor mass;
- performing medium-temperature fabrication steps on said second face;
- attaching a medium-temperature-resistant handle wafer to said second face;
- removing said high-temperature-resistant handle wafer;
- and
- performing medium-temperature fabrication steps on said first face.
9 more elements
A method of fabricating a semiconductor device, comprising:
- performing high-temperature fabrication steps on a first face of a semiconductor wafer;
- introducing first-conductivity-type dopants into first regions on said first face;
- introducing second-conductivity-type dopants into second regions on said first face;
- bonding a high-temperature-resistant handle wafer to said first face;
- performing high-temperature fabrication steps on a second face of said semiconductor wafer which is parallel to said first face;
- introducing first-conductivity-type dopants into third regions on said second face;
- introducing second-conductivity-type dopants into fourth regions on said second face;
- performing a diffusion step at temperatures above about 600° C.;
- whereby said diffusion step diffuses the first-conductivity-type dopants in said first and third regions and the second-conductivity-type dopants in said second and fourth regions to corresponding desired depths in said semiconductor wafer;
- performing medium-temperature fabrication steps on said second face at temperatures below about 450° C.;
- bonding a medium-temperature-resistant handle wafer to said second face;
- removing said high-temperature-resistant handle wafer from said first face;
- performing medium-temperature fabrication steps on said first face at temperatures below about 450° C.;
- removing said medium-temperature-resistant handle wafer from said second face;
- and
- performing low-temperature processing steps on said semiconductor wafer at temperatures below about 240° C.;
- wherein at least some of said high-temperature fabrication steps are performed at temperatures above about 600° C.
14 more elements
A method of fabricating a semiconductor device, comprising:
- performing high-temperature fabrication steps on a first face of a semiconductor wafer;
- introducing first-conductivity-type dopants into first regions on a first face of a semiconductor wafer;
- introducing second-conductivity-type dopants into second regions on said first face;
- forming a protective layer on said first face;
- bonding a high-temperature-resistant handle wafer to said protective layer on said first face;
- thinning said semiconductor wafer, from a second face of said semiconductor wafer which is parallel to said first face, to a desired thickness;
- performing high-temperature fabrication steps on said second face;
- introducing first-conductivity-type dopants into third regions on said second face;
- introducing second-conductivity-type dopants into fourth regions on said second face;
- performing a diffusion step;
- whereby said diffusion step diffuses the first-conductivity-type dopants in said first and third regions and the second-conductivity-type dopants in said second and fourth regions to corresponding desired depths in said semiconductor wafer;
- performing medium-temperature fabrication steps on said second face;
- forming patterned metallization on said second face;
- bonding a medium-temperature-resistant handle wafer to said second face, over said patterned metallization;
- removing said high-temperature-resistant handle wafer from said first face;
- removing said protective layer from said first face;
- performing medium-temperature fabrication steps on said first face;
- forming additional patterned metallization on said first face;
- removing said medium-temperature-resistant handle wafer from said second face;
- and
- performing low-temperature processing steps on said semiconductor wafer at temperatures below about 240° C.;
- wherein the bond between each said handle wafer and said semiconductor wafer is substantially unaffected by temperatures used after the respective bonding step;
- wherein said diffusion step, and at least some said high-temperature fabrication steps, are performed at temperatures above about 600° C.;
- wherein said medium-temperature fabrication steps are performed at temperatures below about 450° C.
21 more elements
Dependencies are inferred from the claim text.