Micropores and methods of making and using thereof

Patent metadata

Field	Value
Publication number	US-9404913-B2
Application number	US-201314057170-A
Country	US
Kind code	B2
Filing date	Oct 18, 2013
Priority date	Jan 24, 2008
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

Disclosed herein are methods of making micropores of a desired height and/or width between two isotropic wet etched features in a substrate which comprises single-level isotropic wet etching the two features using an etchant and a mask distance that is less than 2× a set etch depth. Also disclosed herein are methods using the micropores and microfluidic devices comprising the micropores.

First claim

We claim:

1. A fluidic processing apparatus comprising:
a plurality of features, wherein a first feature is defined by a first mask feature and a
second feature is defined by a second mask feature; and
a plurality of micropores formed between respective ones of the plurality of features, wherein a first micropore is formed at an intersection between the first feature and the second feature,
wherein the first micropore further comprises an opening that is defined by an edge located at the intersection between the first feature and the second feature, and wherein the edge has no appreciable thickness to insignificant thickness,
wherein the first micropore is formed between the first feature and the second feature in a point-to-point configuration or a point-to-edge configuration,
wherein for the point-to-point configuration, a mask distance separating the first mask feature and the second mask feature used to form the first micropore is defined as a minimum distance between tips of two opposing triangles; and wherein for the point-to-edge configuration, the mask distance is defined as a minimum distance between a tip of a triangle and a straight edge,
wherein in the point-to-point configuration, a width, w p2p , of the first micropore is given by:
w p2p =√{square root over (4 d p2p 2 −g p2p 2 +b p2p )},

where d p2p is an etch depth, g p2p is a minimum distance between two features, and b p2p is a
calculated systematic error calculated by a computer configured to:
(1) obtain for a plurality of calibration micropores which
were formed by single-level isotropic wet etching features in the point-to-point configuration in a substrate with an etchant at a set etch depth and at a plurality of mask distances ranging from about 2× or less the set etch depth; and
(2) use nonlinear regression analysis to fit the measured widths to the following equation:
w m =√{square root over (4 *d 2 −g 2 +b )},

where w m is the measured width of the calibration micropore, and
wherein in the point-to-edge configuration, the width, w p2e , of the first micropore is given by:

w

p
⁢

⁢
2
⁢

⁢
e

=

(

2
⁢

⁢

d

p
⁢

⁢
2
⁢
e

-

g

p
⁢

⁢
2
⁢

⁢
e

)

⁢

g

p
⁢

⁢
2
⁢

⁢
e

+

b

p
⁢

⁢
2
⁢

⁢
e

2

,

where d p2e is an etch depth, g p2e is a minimum distance between two features, and b p2e is a calculated systematic error calculated by a computer configured to:
(1) obtain measured widths for a plurality of calibration micropores which were formed by single-level isotropic wet etching features in the point-to-edge configuration in a substrate with an etchant at a set etch depth and at a plurality of mask distances ranging from about 2× or less the set etch depth; and
(2) use nonlinear regression analysis to fit the measured widths w the following equation:
w p2e =2√{square root over ((2 d−g ) g+b )},

where w m is the measured width of the calibration micropore.

2. The apparatus of claim 1 , where a height, h, of the first micropore is given by:
h= ½√{square root over (4 d 2 −g 2 +b )},

where d is etch depth, g is a minimum distance between two features, and b is a calculated systematic error calculated by a computer configured to:
(1) obtain measured widths for a plurality of calibration micropores which were formed by single-level isotropic wet etching features in the point-to-edge configuration in a substrate with an etchant at a set etch depth and at a plurality of mask distances ranging from about 2× or less the set etch depth; and
(2) use nonlinear regression analysis to fit the measured widths w the following equation:
h m =½√{square root over (4 d 2 −g 2 +b )},

where h m is the measured height of the calibration micropore.

3. The apparatus of claim 1 , wherein the first micropore has no appreciable wall thickness.

4. The apparatus of claim 1 , wherein the width of the first micropore is about two times the height of the micropore.

5. The apparatus of claim 1 , wherein the first micropore is less than about 7 μm in height.

6. The apparatus of claim 1 , wherein the first micropore is operable as a hydrodynamic confinement particle trap.

7. The apparatus of claim 1 , wherein the first micropore is operable as a generator of a picoliter droplet.

8. A fluidic apparatus comprising:
a first feature that is defined by a first mask feature;
a second feature that is defined by a second mask feature; and
a first micropore that is formed at an intersection between the first feature and the second feature, and formed by an overlap of wet etch fronts resulting from the first mask feat

Assignees

• Sandia Corp

Inventors

• Perroud Thomas D
• Patel Kamlesh D
• Meagher Robert J

Classifications

• B01L3/502707 Primary

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

• B01L2400/0688

  surface tension valves, capillary stop, capillary break · CPC title

• B01L3/502784

  specially adapted for droplet or plug flow, e.g. digital microfluidics · CPC title

• B81C1/00087

  Holes · CPC title

• B81B2201/058

  Microfluidics not provided for in B81B2201/051 - B81B2201/054 · CPC title