Microscopically structured polymer monoliths and fabrication methods

Patent metadata

Field	Value
Publication number	US-9494865-B2
Application number	US-201013520038-A
Country	US
Kind code	B2
Filing date	Dec 31, 2010
Priority date	Dec 31, 2009
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

Novel polymer monolith structures and methods for fabrication of the same are disclosed in a variety of embodiments. In an illustrative embodiment, a method includes forming a pattern of features on a wafer, thereby forming a patterned wafer; forming a polymer layer on the patterned wafer; using a first plasma to remove at least a portion of the polymer layer; and using a second plasma to etch off at least a portion of the pattern of features, thereby providing a structured polymer monolith. The pattern of features may include an array of pillars. Providing the structured polymer monolith may include providing a structured polymer monolith filter having an array of channels formed by the pillars. The structured polymer monolith may be composed of polypropylene.

First claim

What is claimed is:

1. A method comprising:
forming a pattern of features on a wafer, thereby forming a patterned wafer;
forming a polymer layer on the patterned wafer;
using a first plasma to remove at least a portion of the polymer layer; and
using a second plasma to remove at least a portion of the pattern of features, thereby providing a structured polymer monolith.

2. The method of claim 1 , in which the pattern of features comprises an array of pillars, and in which providing the structured polymer monolith comprises providing a structured polymer monolith filter having an array of channels.

3. The method of claim 1 , in which the structured polymer monolith is composed of a thermoplastic polyolefine.

4. The method of claim 3 , in which the structured polymer monolith is composed of polypropylene.

5. The method of claim 1 , in which forming the polymer layer on the patterned wafer comprises spin-coating a polymer solution onto the patterned wafer.

6. The method of claim 5 , in which the polymer solution is a polypropylene solution.

7. The method of claim 1 , in which forming the pattern of features on the wafer comprises:
applying a photoresist to the wafer;
shining electromagnetic radiation through a patterned photomask at the wafer;
applying a photoresist developer to the wafer; and
etching the wafer.

8. The method of claim 1 , in which the first plasma comprises an oxygen plasma.

9. The method of claim 1 , in which the second plasma comprises a silicon etchant plasma.

10. The method of claim 9 , in which the silicon etchant plasma comprises a sulfur hexafluoride plasma.

11. The method of claim 1 , further comprising applying an electrostatic charge to the structured polymer monolith.

12. A method for fabricating a polypropylene monolith filter comprising an array of microscopic channels, the method comprising:
preparing a patterned photomask configured with an array of dots;
applying a photoresist to a wafer;
shining ultraviolet radiation through the patterned photomask at the wafer;
applying a photoresist developer to the wafer;
etching the wafer, thereby forming a patterned wafer having an array of pillars, corresponding to the array of dots in the patterned photomask, in which the pillars have a diameter of ten microns or less;
spin-coating a polypropylene solution onto the patterned wafer, thereby forming a polypropylene layer on the patterned wafer;
using an oxygen plasma to remove a portion of the polypropylene layer from the patterned wafer, thereby re-exposing at least some of the pillars;
using a silicon etchant plasma to etch away the pillars, thereby providing a polypropylene monolith filter having an array of channels defined where the pillars had been etched away, the channels having a diameter of ten microns or less, and the polypropylene monolith filter having a thickness of 50 microns or less; and
removing the polypropylene monolith filter from the wafer.

13. The method of claim 12 , in which the silicon etchant plasma comprises sulfur hexafluoride.

14. The method of claim 12 , further comprising using a corona charging process to apply an electrostatic charge to the polypropylene monolith filter.

Assignees

• Hinestroza Juan P
• Zhu Huaning
• Univ Cornell

Inventors

• Hinestroza Juan P
• Zhu Huaning

Classifications

• B01D39/1692 Primary

  Other shaped material, e.g. perforated or porous sheets · CPC title

• G03F7/0015

  Production of aperture devices, microporous systems or stamps · CPC title

• B01D2325/08

  Patterned membranes · CPC title

• B01L3/502753

  characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation · CPC title

• B01L3/502707

  characterised by the manufacture of the container or its components · CPC title