US 10,794,374 B2Granted

Microfabricated gas flow structure

AssigneeThe Regents of the University of Michigan

InventorsYogesh Gianchandani, Seungdo An, Yutao Qin

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Abstract

A microfabricated gas flow structure includes an array of vertical gas flow channels in a side-by-side parallel flow arrangement. Adjacent gas flow channels are separated by a thin wall having a thickness which can be an order of magnitude or more less than the channel width, offering exceptionally high area efficiency for the array. Channel walls can be formed from a dielectric material to provide the walls with sufficient integrity at nanoscale thicknesses and to provide thermal insulative properties in the lateral direction, thereby controlling power losses when the gas flow structure is employed as a Knudsen pump. The gas flow structure can be microfabricated as a monolithic structure from an SOI wafer, with the gas flow channels formed in the device layer and the heat sink formed from the handle layer.

Claims19

Dependent claims

A method of microfabricating a gas flow structure comprising an array of gas flow channels supported between first and second support layers at opposite inlet and outlet ends of the gas flow channels, the method comprising the steps of:

(a) forming trenches in a substrate at desired locations of some of the gas flow channels such that unremoved substrate material remains between the trenches at desired locations of more of the gas flow channels;
(b) forming a layer of dielectric material along walls of the trenches such that portions of the dielectric material face each other across each trench;
(c) filling each trench with an etchable material;
(d) removing, after step (c), the substrate material remaining between the trenches such that each of said portions of dielectric material forms a wall shared by adjacent gas flow channels of the array;
(e) forming one or more heat sink channels in the first support layer such that the etchable material is exposed in the formed heat sink channels;
(f) coating walls of the formed heat sink channels with an etch-resistant material;
and
(g) etching the etchable material from between the walls of each trench, wherein the etch-resistant material prevents the first support layer from being etched.

5 more elements

A microfabricated gas flow structure, comprising:

a plurality of parallel walls extending in a gas flow direction between opposite first and second ends, wherein each wall is made from a dielectric material;
a first support layer configured to support the plurality of parallel walls at the first end, the first support layer having one or more gas inlet openings formed therethrough;
and
a second support layer configured to support the plurality of parallel walls at the second end, the second support layer having one or more gas outlet openings formed therethrough,
wherein the plurality of parallel walls is arranged to define an array of hollow channels extending in the gas flow direction between the first and second ends, each hollow channel of the array being separated from an adjacent hollow channel of the array by one of the plurality of parallel walls such that opposite sides of each wall are exposed to separate adjacent hollow channels,
wherein the array of hollow channels fluidly connects the one or more gas inlet openings with the one or more gas outlet openings in an active pumping area of the gas flow structure,
wherein the array of hollow channels defines a thermal isolation zone circumscribing the active pumping area, the hollow channels of the thermal isolation zone being closed off prevent gas flow therethrough, and
wherein each hollow channel of the array is sized for flow in the non-viscous flow regime in the gas flow direction between an inlet side and an outlet side of the structure,
whereby, in the presence of a temperature differential across the inlet and outlet ends, gas flows into the structure through the first support layer in the flow direction, through the array of hollow channels in the flow direction, and out of the structure through the second support layer in the flow direction.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/006,034Filed 25 Jan 2016 · us provisional application
Priority: 25 Jan 2015
Published: US 2016/0230751 A111 Aug 2016
Granted: 6 Oct 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

F04B 37/06
Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00: for evacuating by thermal means
B81C 1/00063
Grooves: trenches
B81C 1/00071
Grooves: channels
C23C 16/45555
Atomic layer deposition [ALD]: applied in non-semiconductor technology