Backside CMOS compatible bioFET with no plasma induced damage
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.
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.
2. The method of claim 1 , further comprising:
thinning the semiconductor substrate from the second surface.
3. 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.
4. 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.
5. The method of claim 1 , further comprising:
coating the sensing film with a hydrophilic or hydrophobic coating.
6. The method of claim 1 , wherein the sensing film is selected from the group consisting of Si3N4, Al 2 O 3 , TiO2, HfO 2 , Ta 2 O 5 , SnO, SnO 2 , Ba x Sr 1-x TiO 3 and combinations thereof.
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.
8. The method of claim 7 , wherein the semiconductor substrate is a silicon-on-insulator (SOI) substrate.
9. 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.
10. The method of claim 9 , wherein the exposing the channel region further comprises:
patterning a photoresist over the insulator layer.
11. 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.
12. 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.
13. The method of claim 7 , further comprising:
modifying a surface property of the microfluidic channel or microfluidic well.
14. 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.
15. The method of claim 14 , 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.
16. The method of claim 14 , wherein sidewalls of the intrinsic dielectric film are formed with a straight profile.
17. The method of claim 14 , further comprising forming a bio-molecule binding coating over the sensing film.
18. The method of claim 14 , wherein the sensing film is selected from the group consisting SiO 2 , Si 3 N 4 , Al 2 O 3 , TiO2, HfO 2 , Ta 2 O 5 , SnO, SnO 2 , Ba x Sr 1-x TiO 3 and combinations thereof.
19. The method of claim 14 , further comprising:
forming a multi-layer interconnect (MLI) on the first side of the semiconductor substrate.
20. The method of claim 14 , 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.