# US 2014/0151755 A1 · Backside cmos compatible biofet with no plasma induced damage

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- Number: US 2014/0151755 A1
- Document ID: US20140151755A1
- Status: Published application
- Kind: A1
- Application number: 13/706,002
- Filed: 2012-12-05
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, L
- Inventors: Yi-Shao Liu; Chun-Ren Cheng; Ching-Ray Chen; Yi-Hsien Chang; Fei-Lung Lai; Chun-Wen Cheng
- Web page: https://patentgrep.com/patent/US20140151755A1

## CPC

- G01N 27/4145: {specially adapted for biomolecules, e.g. gate electrode with immobilised receptors}
- G01N 27/4148: {Integrated circuits therefor, e.g. fabricated by CMOS processing}
- H10D 30/021: {of FETs having insulated gates [IGFET]}
- H10D 84/83: of only insulated-gate FETs [IGFET]
- H10P 50/282: {of inorganic materials}
- 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)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure provides a bio-field effect transistor (BioFET) device and methods of fabricating a BioFET and a BioFET device. The method includes forming a BioFET using one or more process steps compatible with or typical to a complementary metal-oxide-semiconductor (CMOS) process. The BioFET device includes a gate structure disposed on a first surface of a substrate and an interface layer formed on a second surface of the substrate. The substrate is thinned from the second surface to expose a channel region before forming the interface layer.

## Claims

### Claim 1

A method of manufacturing a biological field-effect transistor (BioFET), comprising:
forming a FET device on a semiconductor substrate, wherein the FET device includes a gate structure formed on a first surface of the semiconductor substrate and a channel region;
forming an opening exposing the channel region from a second surface of the semiconductor substrate, wherein a surface of the channel region is exposed by a non-plasma etch; and
forming a sensing film on the channel region of the second surface of the semiconductor substrate in the opening.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
thinning the semiconductor substrate from the second surface.

### Claim 3 (depends on 1)

The method of claim 1, wherein the forming a sensing film on the channel region comprises:
depositing a sensing film over the second surface of the semiconductor substrate;
patterning a photoresist over the sensing film; and
etching an unprotected portion of the sensing film.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
forming a receptor on the sensing film, wherein the receptor is selected from the group consisting of enzymes, antibodies, ligands, peptides, nucleotides, self-assembled molecules.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
coating the sensing film with a hydrophilic or hydrophobic coating.

### Claim 6 (depends on 1)

The method of claim 1, wherein the sensing film is selected from the group consisting of Si3N4, Al2O3, TiO2, HfO2, Ta2O5, SnO, SnO2, BaxSr1-xTiO3 and combinations thereof.

### Claim 7

A method of manufacturing a BioFET device, comprising:
forming a FET device on a semiconductor substrate, wherein the FET device includes a gate structure formed on a first surface of the semiconductor substrate and a channel region in the semiconductor substrate below the gate structure;
attaching the first surface of the semiconductor substrate to a carrier substrate;
forming an opening exposing the channel region from a second surface of the semiconductor substrate by removing a portion of the semiconductor substrate;
forming a sensing film on the channel region of the second surface of the semiconductor substrate in the opening; and
forming a microfluidic channel or microfluidic well over the sensing film.

### Claim 8 (depends on 7)

The method of claim 7, wherein the semiconductor substrate is a silicon-on-insulator (SOI) substrate.

### Claim 9 (depends on 8)

The method of claim 8, wherein the SOI substrate includes a first semiconductor layer and a second semiconductor layer interposed by an insulator layer, wherein the exposing the channel region comprises:
thinning the SOI substrate to remove a semiconductor layer opposite of the semiconductor layer on which the FET is formed; and
etching the insulator layer to expose the channel region, wherein the etching is wet etch or non-plasma dry etch.

### Claim 10 (depends on 9)

The method of claim 9, wherein the exposing the channel region further comprises:
patterning a photoresist over the insulator layer.

### Claim 11 (depends on 7)

The method of claim 7, wherein the forming a microfluidic channel or microfluidic well comprises:
depositing a microfluidic structure material;
patterning the microfluidic structure material.

### Claim 12 (depends on 7)

The method of claim 7, wherein the forming a microfluidic channel or microfluidic well comprises:
bonding a microfluidic structure to the second surface of the semiconductor substrate.

### Claim 13 (depends on 7)

The method of claim 7, further comprising:
modifying a surface property of the microfluidic channel or microfluidic well.

### Claim at position 14

14-20. (canceled)

### Claim 21

A method, comprising:
forming a first BioFET device including:
forming 22 a gate structure on a first side of a semiconductor substrate;
forming a source region and a drain region in the semiconductor substrate adjacent to the gate structure;
forming a channel region interposing the source and drain regions and underlying the gate structure;
attaching the first BioFET device to a carrier substrate;
removing a portion of a second side of the substrate to expose at least a portion of the channel region;
forming a sensing film directly on and covering at least a portion of the exposed channel region; and
forming at least one of a microfluidic channel and a microfluidic well over the sensing film.

### Claim 22 (depends on 21)

The method of claim 21, further comprising:
forming an intrinsic dielectric film between the first BioFET device and a microfluidic structure containing the patent least one of the microfluidic channel and the microfluidic well, the intrinsic dielectric film surrounding the at least a portion of the channel region covered by the sensing film.

### Claim 23 (depends on 21)

The method of claim 21, wherein sidewalls of the intrinsic dielectric film are formed with a straight profile.

### Claim 24 (depends on 21)

The method of claim 21, further comprising forming a bio-molecule binding coating over the sensing film.

### Claim 25 (depends on 21)

The method of claim 21, wherein the sensing film is selected from the group consisting SiO2, Si3N4, Al2O3, TiO2, HfO2, Ta2O5, SnO, SnO2, BaxSr1-xTiO3 and combinations thereof.

### Claim 26 (depends on 21)

The method of claim 21, further comprising:
forming a multi-layer interconnect (MLI) on the first side of the semiconductor substrate.

### Claim 27 (depends on 21)

The method of claim 21, further comprising:
forming a second BioFET connected to the first BioFET by a microfluidic channel; and
forming a third BioFET and a fourth BioFET connected to a second microfluidic channel, wherein the first, second, third and fourth BioFETs are disposed in an array configuration.