Biosensing well array with protective layer

Patent metadata

Field	Value
Publication number	US-9417209-B2
Application number	US-201514703724-A
Country	US
Kind code	B2
Filing date	May 4, 2015
Priority date	Sep 20, 2013
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

The present disclosure provides a biological field effect transistor (BioFET) and a method of fabricating 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 includes a microwells having a sensing layer, a top metal stack under the sensing layer, and a multi-layer interconnect (MLI) under the top metal stack. The top metal stack includes a top metal and a protective layer over and peripherally surrounding the top metal.

First claim

What is claimed is:

1. A biological field-effect transistor (BioFET) device, comprising:
a substrate; and
a plurality of BioFETs, each BioFET comprising:
a plurality of microwells having a bottom and sidewalls, wherein the bottom and at least a portion of the sidewalls is a sensing layer;
a plurality of top metal stacks under the plurality of microwells, each of the plurality of top metal stacks being under one microwell, wherein each of the plurality of the top metal stacks includes an underlayer, a top metal over a top surface of the underlayer and not extending below the top surface of the underlayer, and a protective layer over and along a sidewall of the top metal, wherein a portion of the protective layer extends lower than an uppermost surface of the underlayer and wherein the underlayer and the protective layers are conductive; and
one or more transistors, wherein a gate of each of the one or more transistors is connected to one of the plurality of top metal stacks through intervening metal layers.

2. The BioFET device of claim 1 , further comprising a metal pad having a top surface below a plane of top surfaces of the plurality of top metal stacks.

3. The BioFET device of claim 1 , wherein the each of the plurality of top metal stacks also includes an antireflective layer over the top metal and under the protective layer.

4. The BioFET device of claim 1 , wherein a thickness of the protective layer on sidewalls of the top metal stacks is greater than 200 angstroms.

5. The BioFET device of claim 1 , wherein a thickness of the protective layer on sidewalls of the top metal stacks is about 300 angstroms.

6. The BioFET device of claim 1 , wherein the protective layer comprises titanium nitride.

7. The BioFET device of claim 1 , further comprising:
a fluidic channel fluidly connecting the microwells between the plurality of BioFETs.

8. The BioFET device of claim 1 , wherein a bottom surface area of each of the plurality of microwells is larger than a top surface of the top metal.

9. The BioFET device of claim 1 , wherein the sensing layer comprises a high-k dielectric.

10. The BioFET device of claim 1 , wherein the sensing layer is disposed between a top portion of the plurality of top metal stacks and a passivation layer, wherein the passivation layer is disposed between each of the plurality of BioFETs.

11. The BioFET device of claim 10 , wherein the sensing layer does not cover a top surface of the passivation layer.

12. A device, comprising:
a substrate; and
a BioFET structure including:
a microwell having a bottom and sidewalls, wherein the bottom and at least a portion of the sidewalls form a sensing layer;
a top metal stack under the microwell, wherein the top metal stack includes a major conductive feature sandwiched between a conductive underlayer and a conductive protective layer, the conductive protective layer being conformal to a top surface and one or more sidewalls of the major conductive feature and extending to an uppermost surface of the underlayer, the major conductive feature not extending below the uppermost surface of the underlayer; and
a transistor, electrically connected to the major conductive feature through one or more intervening metal layers.

13. The device of claim 12 , wherein the microwell is formed in a passivation layer formed over the top metal stack.

14. The device of claim 12 , wherein the protective layer comprises titanium nitride.

15. The device of claim 12 , further including an anti-reflective coating sandwiched between the major conductive feature and the conductive protective layer.

16. The device of claim 12 , wherein the bottom of the microwell is substantially aligned with the major conductive feature.

17. A device comprising:
a transistor;
a interconnect structure electrically connected to the transistor, the interconnect structure including a top metal stack comprising: a conductive underlayer, a conductive line atop the underlayer and not along sides of the underlayer, and a conductive protective layer atop the conductive line and extending along sidewalls of the conductive line;
a passivation layer atop the top metal stack having a microwell formed therein, wherein sidewalls of the microwell are formed from the passivation layer and a bottom of the microwell is formed from the conductive protective layer; and
a sensing layer lining the bottom and at least partially lining the sidewalls of the microwell, wherein an uppermost surface of the passivation layer extends above the sensing layer.

18. The device of claim 17 , wherein the conductive protective layer comprises titanium nitride.

19. The device of claim 17 , wherein the interconnect structure includes a plurality of conductive elements vertically stacked atop one another and electrically interconnected by conductive vias.

20. The device of claim 17 , wherein the top metal stack is vertically aligned to the transistor.

21. The device of claim 17 , wherein the sensing layer extends from a top to a bottom of the sidewalls.

22. The device of claim 17 , wherein a portion of the protective layer extends lower than an uppermost surface of the underlayer.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Shen Wei-Cheng
• Chang Yi-Hsien
• Lin Shih-Wei
• Cheng Chun-Ren

Classifications

• G01N27/4145 Primary

  specially adapted for biomolecules, e.g. gate electrode with immobilised receptors · CPC title

• G01N27/4148

  Integrated circuits therefor, e.g. fabricated by CMOS processing · CPC title