# US 12,222,316 B2 · Semiconductor device providing a biosensor to test for pathogen

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- Number: US 12,222,316 B2
- Document ID: US12222316B2
- Status: Granted
- Kind: B2
- Application number: 17/171,691
- Filed: 2021-02-09
- Published: 2022-07-28
- Granted: 2025-02-11
- Earliest claimed: 2021-01-26
- Assignees: Icemos Technology Ltd.
- Applicants: IceMos Technology Limited
- Inventors: Samuel J. Anderson; Hugh J. Griffin
- Web page: https://patentgrep.com/patent/US12222316B2

## CPC

- G01N 27/3276: {being a hybridisation with immobilised receptors (using a FET type sensor G01N27/4145; concerning the hybridisation C12Q1/68)}
- G01N 27/4145: {specially adapted for biomolecules, e.g. gate electrode with immobilised receptors}
- G01N 27/3272: {Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels (optical biosensors G01N33/52)}
- G01N 27/4146: {involving nanosized elements, e.g. nanotubes, nanowires}
- G01N 33/539: involving precipitating reagent {, e.g. ammonium sulfate}
- G01N 27/413: Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

An atomic level deposition for mass functionalization of a cavity filled with a pathogen sensitive antibody reagent to functionalize each biosensor using atomic level vapor phase deposition enables high volume production of this sensor technology. A biosensor has a first substrate and a second substrate with a cavity formed in the first substrate to form a membrane. Holes are formed through the second substrate. An aluminum oxide layer is formed over the cavity and into the holes to form cores. The cavity is filled with a pathogen sensitive antibody reagent. A biofluid sample with the pathogen is deposited over the membrane. The biofluid is drawn through the cores to mix with the antibody reagent. The antibodies combine with the pathogen to change the impedance along the current path. The presence of the pathogen changes the ionic current flow through the biosensor for a positive detection of the pathogen.

## Claims

### Claim 1

A method of making a semiconductor device, comprising:
providing a substrate;
forming a buried oxide layer over the substrate;
forming a device layer over the buried oxide layer
forming a cavity through the substrate while leaving the buried oxide layer disposed over the cavity, wherein a portion of the device layer and buried oxide layer disposed over the cavity forms a membrane;
forming a plurality of openings through the membrane and extending to the cavity;
depositing aluminum oxide over a sidewall of the openings through the membrane and further over the buried oxide layer within the cavity; and
forming a backside contact over a surface of the substrate opposite the device layer, wherein the backside contact includes a port extending into the cavity adapted to introduce a reactive solution into the cavity.

### Claim 2 (depends on 1)

The method of claim 1, further including forming the device layer over the substrate by direct wafer bonding.

### Claim 3 (depends on 1)

The method of claim 1, further including forming a plurality of posts within the cavity to support the membrane at locations within the cavity.

### Claim 4 (depends on 3)

The method of claim 3, further including forming the posts by deep reactive ion etching.

### Claim 5 (depends on 3)

The method of claim 3, wherein the posts allow for microfluids flows of reagent solution when converted from vapor phase to liquid solution.

### Claim 6 (depends on 1)

The method of claim 1, further including forming an oxide layer between the substrate and device layer.

### Claim 7 (depends on 1)

The method of claim 1, further including forming a sacrificial thermal oxide on a surface within the holes.

### Claim 8 (depends on 7)

The method of claim 7, further including removing the sacrificial thermal oxide.

### Claim 9 (depends on 7)

The method of claim 7, further including removing the sacrificial thermal oxide by wet chemistry followed by hydrofluoric acid vapor phase fuming to smooth the surface within the holes.

### Claim 10 (depends on 1)

The method of claim 1, further including depositing the aluminum oxide over a sidewall of the cavity and a surface of the buried oxide layer.

### Claim 11 (depends on 1)

The method of claim 1, further including forming a backside contact over a surface of the substrate opposite the device layer, wherein the backside contact includes a port extending into the cavity adapted to introduce a reactive solution into the cavity.

### Claim 12

A method of making a biosensor, comprising:
providing a first substrate;
forming a buried oxide layer over the first substrate;
disposing a second substrate over the buried oxide layer;
forming a cavity through the first substrate while leaving the buried oxide layer disposed over the cavity, wherein a portion of the second substrate and buried oxide layer disposed over the cavity forms a membrane;
forming a plurality of holes through the membrane including the second substrate and the buried oxide layer disposed over the cavity; and
forming a backside contact over a surface of the substrate opposite the device layer, wherein the backside contact includes a port extending into the cavity adapted to introduce a reactive solution into the cavity.

### Claim 13 (depends on 12)

The method of claim 12, further including forming the holes through the second substrate by atomic level deposition.

### Claim 14 (depends on 12)

The method of claim 12, further including forming a sacrificial thermal oxide on a surface within the holes.

### Claim 15 (depends on 14)

The method of claim 14, further including removing the sacrificial thermal oxide by wet chemistry followed by hydrofluoric acid vapor phase fuming to smooth the surface within the holes.

### Claim 16 (depends on 14)

The method of claim 14, further including removing the sacrificial thermal oxide by wet chemistry followed by hydrofluoric acid vapor phase fuming to smooth the surface within the holes.

### Claim 17 (depends on 12)

The method of claim 12, further including forming a layer of material over a surface of the cavity and into the holes to form a plurality of cores.

### Claim 18 (depends on 12)

The method of claim 12, further including introducing a reagent solution in vapor phase through the port and into the cavity.

### Claim 19 (depends on 18)

The method of claim 18, further including introducing the reagent solution in vapor phase into the cavity by atomic level vapor phase deposition.

### Claim 20 (depends on 18)

The method of claim 18, wherein introducing the reagent solution in vapor phase into the cavity by atomic level vapor phase deposition provides mass functionality of the cores.

### Claim 21 (depends on 12)

The method of claim 12, further including depositing aluminum oxide over a sidewall of the openings through the membrane and further over the buried oxide layer within the cavity.

### Claim 22

A method of making a biosensor, comprising:
providing a substrate;
forming a buried oxide layer over the substrate;
disposing a device layer over the buried oxide layer;
forming a cavity through the substrate while leaving the buried oxide layer disposed over the cavity to form a membrane as a portion of the device layer and buried oxide layer disposed over the cavity; and
forming a plurality of holes through the membrane including the device layer and the buried oxide layer disposed over the cavity.

### Claim 23 (depends on 22)

The method of claim 22, further including forming a sacrificial thermal oxide on a surface within the holes.

### Claim 24 (depends on 23)

The method of claim 23, further including removing the sacrificial thermal oxide.

### Claim 25 (depends on 22)

The method of claim 22, further including forming a layer of material over a surface of the cavity and into the holes to form a plurality of cores.

### Claim 26 (depends on 22)

The method of claim 22, further including forming the holes through the device layer by atomic level deposition.

### Claim 27 (depends on 22)

The method of claim 22, further including introducing a reagent solution in vapor phase through the port and into the cavity.

### Claim 28 (depends on 27)

The method of claim 27, further including introducing the reagent solution in vapor phase into the cavity by atomic level vapor phase deposition.