Porous flat deformation-resistant membrane
AssigneeGlobal Life Sciences Solutions USA LLC
InventorsWilliam A Hennessy, Douglas Albagli
Life of this patent
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Abstract
Porous membranes are provided according to the invention having desirable coefficient of thermal expansion and large surface area, for example at least about 4,000 mm2. These porous membranes may be made according to an exemplary process employing lithographic patterning of a photoresist followed by development of the photoresist and etching. In one aspect, the etch barrier layer is chosen from a material that does not react with or incorporate metal or other contaminants into the membrane layer.
Claims13
A method for making a liquid-filtering porous membrane comprising:
- a) depositing a photoresist layer on the top surface of a substrate, the substrate comprising a support layer, a polymer layer, and a hard mask layer, wherein the polymer layer has a thickness of between 5 to 25 microns and the polymer layer being of polyimide having a matched coefficient of thermal expansion that is within ±25% relative to the support layer;
- b) exposing the photoresist to a pattern of light;
- c) developing the photoresist layer to provide a first pattern of openings in the photoresist layer that expose portion of the hard mask layer;
- d) etching the exposed portions of the hard mask layer to provide a second pattern of openings in the hard mask layer that expose portions of the underlying polymer layer;
- e) removing the photoresist;
- f) etching the polymer layer through the openings in the hard mask layer thereby providing a third pattern of openings in the polymer layer;
- g) removing the hard mask layer;
- and
- h) releasing the polymer layer from the support layer, thereby providing the porous membrane, wherein the pore dimensions of the porous membrane are defined by the pattern of light and membrane has a surface area of at least 4,000 mm2, wherein the hard mask layer comprises hydrogenated amorphous SiN (SiN:H) or hydrogenated amorphous SiO (SiO:H).
A method for making a liquid-filtering porous membrane comprising:
- a) depositing a photoresist layer on the top surface of a glass substrate, the substrate comprising a support layer, a polymer layer, and a hard mask layer, wherein the polymer layer has a thickness of between 5 to 25 microns and the polymer layer being of polyimide having a matched coefficient of thermal expansion that is within ±25% relative to the glass substrate, the hard mask layer comprising hydrogenated amorphous SiN (SiN:H) or hydrogenated amorphous SiO (SiO:H);
- b) exposing the photoresist to a pattern of light;
- c) developing the photoresist layer to provide a first pattern of openings in the photoresist layer that expose portion of the hard mask layer;
- d) etching the exposed portions of the hard mask layer to provide a second pattern of openings in the hard mask layer that expose portions of the underlying polymer layer;
- e) removing the photoresist;
- f) etching the polymer layer through the openings in the hard mask layer thereby providing a third pattern of openings in the polymer layer;
- g) removing the hard mask layer;
- and
- h) releasing the polymer layer from the support layer, thereby providing the porous membrane, wherein the pore dimensions of the porous membrane are defined by the pattern of light and membrane has a surface area of at least 4,000 mm2.
Dependencies are inferred from the claim text.