Membrane dielectric isolation IC fabrication
First Claim
1. A method of forming a transistor structure comprising:
- providing a flexible membrane having a first dielectric layer and a semiconductor layer;
forming at least a pair of isolation trenches through the semiconductor layer, said isolation trenches filled with dielectric material;
covering the semiconductor layer with a second dielectric layer;
forming a window through the second dielectric layer and semiconductor layer;
etching the semiconductor layer to form a cavity between the first and second dielectric layers and between the pair of isolation trenches; and
forming at least three regions of doped semiconductor material of alternating polarity within the cavity.
2 Assignments
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Accused Products
Abstract
General purpose methods for the fabrication of integrated circuits from flexible membranes formed of very thin low stress dielectric materials, such as silicon dioxide or silicon nitride, and semiconductor layers. Semiconductor devices are formed in a semiconductor layer of the membrane. The semiconductor membrane layer is initially formed from a substrate of standard thickness, and all but a thin surface layer of the substrate is then etched or polished away. In another version, the flexible membrane is used as support and electrical interconnect for conventional integrated circuit die bonded thereto, with the interconnect formed in multiple layers in the membrane. Multiple die can be connected to one such membrane, which is then packaged as a multi-chip module. Other applications are based on (circuit) membrane processing for bipolar and MOSFET transistor fabrication, low impedance conductor interconnecting fabrication, flat panel displays, maskless (direct write) lithography, and 3D IC fabrication.
121 Citations
16 Claims
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1. A method of forming a transistor structure comprising:
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providing a flexible membrane having a first dielectric layer and a semiconductor layer; forming at least a pair of isolation trenches through the semiconductor layer, said isolation trenches filled with dielectric material; covering the semiconductor layer with a second dielectric layer; forming a window through the second dielectric layer and semiconductor layer; etching the semiconductor layer to form a cavity between the first and second dielectric layers and between the pair of isolation trenches; and forming at least three regions of doped semiconductor material of alternating polarity within the cavity. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming a transistor comprising:
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providing a flexible membrane of low stress dielectric with a principal surface; depositing a semiconductor layer on the principal surface of the membrane; isolating the semiconductor layer in dielectric material; epitaxially growing three doped regions from the semiconductor layer; and forming an electrical contact to a first of the three doped regions and forming an electrical contact to a second of the three doped regions. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of making a transistor using a membrane having a semiconductor layer interposed between first and second dielectric layers, the method comprising the steps of:
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patterning the first dielectric layer so as to expose a portion of the semiconductor layer; anisotropically etching an opening in the semiconductor layer to a degree that an opening of a desired dimension is formed in the second dielectric layer; epitaxially growing the semiconductor layer to close the opening thereof; and forming a first contact in a region of the opening in the second dielectric layer. - View Dependent Claims (13, 14, 15)
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16. A method of forming an MOS transistor in which a gate region of the MOS transistor is non-lithographically defined, comprising the steps of:
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epitaxially growing semiconductor material having a specified doping within a gate region of the MOSFET such that gate region geometry is controlled by control of the epitaxial growth; and forming a conductive gate in opposed relation to the gate region.
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Specification