Microfabricated filter and capsule using a substrate sandwich
First Claim
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1. A filter comprising:
- a first substrate structure directly bonded to a second substrate structure; and
,at least one pore located between the first and second substrate structures having a pore size less than about 500 nm and having a pore uniformity of ±
1-3 nm,wherein said first substrate structure and second substrate structure each comprise single crystalline silicon.
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Abstract
A microfabricated filter made up of two bonded substrate structures, each consisting of single crystalline silicon can optionally be formed into a capsule. The pores of the filter consist of one or more channels disposed between the two substrate structures. The width of the channels are defined by a thickness of a sacrificial layer formed on one of the substrate structures. The filter includes pores having a precisely controlled pore width which may be as small as 5 nanometers. The filter provides a relatively high mechanical strength relative to filters having polycrystalline silicon structures and also has a high throughput and can be modified to have high resistance to adsorption of particles.
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Citations
31 Claims
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1. A filter comprising:
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a first substrate structure directly bonded to a second substrate structure; and
,at least one pore located between the first and second substrate structures having a pore size less than about 500 nm and having a pore uniformity of ±
1-3 nm,wherein said first substrate structure and second substrate structure each comprise single crystalline silicon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of fabricating a filter comprising the steps of:
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providing a first single crystalline silicon substrate having masked and unmasked portions; depositing a first sacrificial layer having a thickness t on said unmasked portions; creating a pore width of about t÷
2.27±
1-5 nm by removing said first sacrificial layer from said first single crystalline substrate forming a recess; anddirectly bonding a second single crystalline silicon substrate to the first crystalline substrate. - View Dependent Claims (18, 19)
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20. A capsule having a porous region comprising:
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a first substrate structure having at least one first cavity; a second substrate structure having at least one second cavity directly bonded to said first substrate structure, wherein said at least one first and second cavity define at least one chamber; at least one pore having a pore size of less than about 500 nm and having a pore uniformity of ±
1-3 nm,wherein said first and second substrate structures each comprise since crystalline silicon. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A method of fabricating a capsule having a porous region comprising the steps of:
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providing a first single crystalline silicon substrate; forming a recess in said first single crystalline silicon substrate; forming a first cavity in said first single crystalline silicon substrate; providing a second single crystalline silicon substrate; forming a second cavity in said second single crystalline silicon substrate; and directly bonding said first and second single crystalline silicon substrates, wherein the first and second cavities are aligned. - View Dependent Claims (28, 29, 30)
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31. A capsule comprising:
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a plurality of directly bonded single crystalline silicon substrates having a plurality of anchor points each located between the substrates; a plurality of chambers each located between the substrates; and
,a plurality of pores, each located between the substrates, each having a pore size less than about 500 nm, and having a pore uniformity of about ±
1-3 nm.
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Specification