Hybrid diamond-polymer thin film sensors and fabrication method
Inventors
Li, Wen • Fan, Bin • RECHENBERG, Robert • Becker, Michael • RUSINEK, Cory
Assignees
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Publication Number
US-10667709-B2
Publication Date
2020-06-02
Expiration Date
Abstract
An implantable device is provided. The implantable device includes a flexible polymeric substrate that extends through an aperture in an electrically conductive material to form an anchor that partially covers the electrically conductive material. Methods for fabricating the implantable device are also provided.
Core Innovation
The invention relates to hybrid flexible implantable sensor devices fabricated by generating a layer of SiO2 on a surface of a substrate, disposing a layer of an electrically conductive material, and defining a pattern that includes a plurality of apertures. The apertures extend through the electrically conductive material and optionally through the layer of SiO2 to the substrate, and an etching compound is applied into the apertures to etch the SiO2 vertically downward to the Si substrate and to etch a portion of the SiO2 horizontally beneath the electrically conductive material to form a plurality of undercuts.
A flexible polymeric material is disposed over the electrically conductive material so that it fills the undercuts and covers the electrically conductive material, thereby forming polymer coverage in the undercut regions beneath the patterned conductive material. The substrate and the remainder of the SiO2 are then removed by etching to generate the flexible device, and in further embodiments the electrically conductive material includes boron doped polycrystalline diamond (BDD) and the flexible polymeric material includes parylene-C.
Another aspect of the invention is a flexible device architecture in which an electrically conductive material defines a predetermined pattern with at least one aperture extending from a first surface to a second opposing surface of the electrically conductive material. The second surface of the electrically conductive material is disposed on a flexible polymeric substrate, and the flexible polymeric substrate extends through the aperture to the first surface while extending radially on the first surface about the aperture to form an anchor that partially covers the electrically conductive material.
The flexible device is an implantable probe or sensor configured so that its Young's modulus is closer to the Young's modulus of a human brain relative to the Young's modulus of boron doped polycrystalline diamond (BDD).
Claims Coverage
The independent claims present four inventive features centered on fabrication of flexible devices with aperture-defined patterned electrically conductive material, SiO2 etching and undercut formation, polymer filling and anchoring, and a final implantable probe or sensor structure with reduced stiffness.
A flexible device fabrication method using SiO2 vertical and horizontal etching with polymer undercut filling
A method of fabricating a flexible device comprising generating a layer of SiO2 on a surface of a substrate, disposing a layer of an electrically conductive material on the layer of SiO2, removing a portion of the electrically conductive material to define a pattern including a plurality of apertures, applying an etching compound into the apertures to etch SiO2 vertically downward to the Si substrate when the apertures do not extend through the layer of SiO2 and to etch a portion of the layer of SiO2 horizontally beneath the electrically conductive material to form a plurality of undercuts, disposing a flexible polymeric material over the electrically conductive material such that the flexible polymeric material fills the undercuts and covers the electrically conductive material, and removing the substrate and the remainder of the SiO2 by etching to generate the flexible device.
A fabrication method using BDD conductive material with parylene-C filling undercuts and leaving polymer on both sides
A method of fabricating a flexible device comprising generating a layer of SiO2 on a surface of a silicon (Si) substrate, disposing a layer of boron doped polycrystalline diamond (BDD) on the layer of SiO2, removing a portion of the BDD to define a pattern including a plurality of apertures that extend through the BDD and optionally through the layer of SiO2 to the substrate, applying an etching compound into the apertures to etch the SiO2 vertically downward to the Si substrate when the apertures do not extend through the layer of SiO2 and to etch a portion of the layer of SiO2 horizontally beneath the electrically conductive material to form a plurality of undercuts, disposing parylene-C over the BDD to fill the undercuts and cover the BDD, removing a portion of the parylene-C located above the BDD, inverting the device and removing a top portion of the parylene-C and substantially all of the Si substrate, inverting the device and removing the remainder of the SiO2, disposing additional parylene-C over top and bottom surfaces of the BDD by chemical vapor deposition, and removing the parylene-C disposed on the top surface of the BDD.
A fabrication method using horizontal SiO2 undercut formation under a patterned conductive layer filled by a flexible polymer
A method of fabricating a flexible device comprising generating a layer of SiO2 on a surface of a substrate, placing a layer of an electrically conductive material comprising boron doped polycrystalline diamond on the layer of SiO2, removing a portion of the electrically conductive material to define a pattern, etching a portion of the layer of SiO2 horizontally beneath the electrically conductive material to form at least one undercut, placing a flexible polymeric material over the electrically conductive material to fill the at least one undercut and cover the electrically conductive material, and removing the substrate and the remainder of the SiO2 by etching to create the flexible device.
A flexible implantable probe or sensor with aperture-defined conductive pattern and radially covered polymer anchor for Young's modulus matching
A flexible device comprising an electrically conductive material that defines a predetermined pattern including at least one aperture extending from a first surface of the electrically conductive material to a second opposing surface of the electrically conductive material, and a flexible polymeric substrate, wherein the second surface of the electrically conductive material is disposed on the flexible polymer substrate and the flexible polymeric substrate extends through the at least one aperture from the second surface to the first surface and extends radially on the first surface about the at least one aperture to form an anchor that partially covers the electrically conductive material, and wherein the flexible device is an implantable probe or sensor having a Young's modulus that is closer to the Young's modulus of a human brain relative to the Young's modulus of boron doped polycrystalline diamond (BDD).
Across the independent claims, the core claimed coverage centers on fabricating a flexible device by creating a patterned electrically conductive material with apertures, forming vertical and/or horizontal SiO2 etch regions including undercuts beneath the conductive material, filling and covering those undercuts with a flexible polymeric material to create polymer anchoring, removing the underlying substrate and remaining SiO2 to release the device, and forming a final implantable probe or sensor architecture in which the polymer substrate extends through apertures and radially covers the conductive material.
Stated Advantages
The flexible device is an implantable probe or sensor having a Young's modulus that is closer to the Young's modulus of a human brain relative to the Young's modulus of boron doped polycrystalline diamond (BDD).
Documented Applications
An implantable probe or sensor configuration, including an embodiment configured for implantation in neural tissue.
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