Methods and systems for point of use removal of sacrificial material

• US 9,080,968 B2
• Filed: 01/04/2013
• Issued: 07/14/2015
• Est. Priority Date: 01/04/2013
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Inman, Christina, Hinz, Wolfgang, Li, Shifeng, Benson, Scott, Mastroianni, Alexander
• Primary Examiner(s): CHAUDHARI, CHANDRA P
• Application Number:
  US13/734,696
• Publication Number:
  US 20140191292A1
• Time in Patent Office: 921 Days
• Field of Search: 257/253, 257/E29.166
• US Class Current: 1/1
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: H01L 21/31105 Etching inorganic layers
• CPC Class Codes: H01L 21/31144 using masks

Abstract

A method of manufacturing a sensor, the method including forming an array of chemically-sensitive field effect transistors (chemFETs), depositing a dielectric layer over the chemFETs in the array, depositing a protective layer over the dielectric layer, etching the dielectric layer and the protective layer to form cavities corresponding to sensing surfaces of the chemFETs, and removing the protective layer. The method further includes, etching the dielectric layer and the protective layer together to form cavities corresponding to sensing surfaces of the chemFETs. The protective layer is at least one of a polymer, photoresist material, noble metal, copper oxide, and zinc oxide. The protective layer is removed using at least one of sodium hydroxide, organic solvent, aqua regia, ammonium carbonate, hydrochloric acid, acetic acid, and phosphoric acid.

Claims

1. A sensor, comprising:

an array of chemically-sensitive field effect transistors (chemFETs), each chemFET in the array having a floating gate structure including an upper surface;

a dielectric layer over the upper surfaces of the floating gate structures of the chemFETs in the array, the dielectric layer including cavities extending to the upper surfaces of the floating gate structures and corresponding to sensing surfaces of the chemFETs;

a conformal protective layer over the sensing surfaces, sidewalls of the cavities, and top surface of the array.

2. The sensor of claim 1, wherein the protective layer defines a removable layer.

3. The sensor of claim 1, wherein the protective layer is at least one of a polymer, photoresist, noble metal, copper oxide, and zinc oxide.

4. The sensor of claim 1, wherein the protective layer is removed using at least one of sodium hydroxide, organic solvent, aqua regia, ammonium carbonate, hydrochloric acid, acetic acid, and phosphoric.

5. The sensor of claim 1, wherein the dielectric layer includes at least one of silicon oxide, silicon nitride and silicon oxynitride.

6. The sensor of claim 1, wherein the sensing surface comprises at least one of tantalum oxide, titanium oxide, and titanium nitride.

7. The sensor of claim 1, wherein the sensing surface comprises a metal oxide or metal nitride selected from one or more of the group of Al₂O₃, Ta₂O₅, HfO₃, WO₃, ZrO₂, TiO₂ or mixtures thereof.