Process for manufacturing a microfluidic device with buried channels

• US 20050282221A1
• Filed: 07/28/2005
• Published: 12/22/2005
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Villa, Flavio, Corona, Pietro, Barlocchi, Gabriele, Mastromatteo, Ubaldo
• Granted Patent: US 7,452,713 B2
• Time in Patent Office: Days
• US Class Current: 435/6.11
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 3/5025 for parallel transport of multiple samples
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B01L 7/52 with provision for submitting samples to a predetermined sequence of different temperatures, e.g. for treating nucleic acid samples amplification or hybridisation processes per se C12Q1/68; controlling sequential reactions for synthesis B01J19/0046

Abstract

A process for manufacturing a microfluidic device, including the steps of: forming at least one channel in a semiconductor material body; forming a dielectric diaphragm above the channel, for closing the channel; and forming heating elements for providing thermal energy inside the channel. The heating elements are formed directly on said dielectric diaphragm.

Claims

1. A process for manufacturing a microfluidic device, comprising the steps of:

forming at least one channel in a semiconductor material body;

forming a dielectric diaphragm above said channel, for closing said channel; and

forming heating elements for providing thermal energy inside said channel;

wherein said heating elements are formed directly on said dielectric diaphragm.

2. The process according to claim 1, wherein said step of forming at least one channel comprises:

forming a mask on top of said semiconductor material body; and

anisotropically etching said semiconductor material body using said mask; and

wherein said mask has a plurality of openings, each having a side or a prevalent direction with an inclination of between 44° and

46°

with respect to a flat of said semiconductor material body.

3. The process according to claim 2, characterized in that said openings have a side or a prevalent direction with an inclination of 45°

with respect to said flat of said semiconductor material body.

4. The process according to claim 2, wherein said step of forming said dielectric diaphragm comprises closing said openings.

5. The process according to claim 4, wherein closing said openings comprises:

depositing a coating film of a semiconductor material, partially occluding said apertures;

thermally oxidizing said coating film, thereby narrowing said openings; and

depositing a closing layer of a dielectric material, for completely closing said openings.

6. The process according to claim 1, comprising the step of forming temperature sensors and an array of electrodes directly on said dielectric diaphragm, said array of electrodes being arranged at one end of said at least one channel.

7. The process according to claim 6, comprising the step of depositing a protective layer for covering said heating elements, said temperature sensors and said electrodes.

8. The process according to claim 1, comprising the step of etching said dielectric diaphragm for opening inlets and outlets at opposite ends of said at least one channel.

9. The process according to claim 8, comprising the steps of:

forming an inlet reservoir and a recess in a separate wafer; and

bonding said separate wafer to said dielectric diaphragm;

wherein said inlet reservoir and said recess are arranged such that, once said separate wafer has been bonded to said dielectric diaphragm, said inlets are accessible from outside through said inlet reservoir, said outlets communicate to said recess and said electrodes are located in said recess.

10. The process according to claim 8, wherein, before opening said inlets and said outlets, a structural layer of a polymeric material is deposited on said dielectric diaphragm and inlet reservoir and a recess are formed in said structural layer.

11. The process according to claim 2, wherein said anisotropic etching step is carried out using TMAH.

12. A microfluidic device, comprising:

at least one channel buried in a semiconductor material body;

a dielectric diaphragm above said channel, for closing said channel; and

heating elements for providing thermal energy inside said channel;

wherein said heating elements are arranged directly on said dielectric diaphragm.

13. The device according to claim 12, comprising the temperature sensors and an array of electrodes directly formed on said dielectric diaphragm, said array of electrodes being arranged at one end of said channel.

14. The device according to claim 13, comprising a protective layer covering said heating elements, said temperature sensors and said electrodes.

15. The device according to claim 13, comprising inlets and outlets formed through said dielectric diaphragm at opposite ends of said at least one channel.

16. The device according to claim 15, comprising:

a structure formed on said dielectric diaphragm; and

an inlet reservoir and a recess formed in said structure, wherein said inlet reservoir and said recess are arranged such that said inlets are accessible from outside through said inlet reservoir, said outlets communicate to said recess and said electrodes are located in said recess.

17. The device according to claim 16, wherein said structure includes a separate wafer bonded on said dielectric diaphragm

18. The device according to claim 16, wherein said structure includes a structural layer of a polymeric material deposited on said dielectric diaphragm.

19. A method of analyzing a biological sample, comprising

applying a biological sample to microfluidic device comprising at least one channel buried in a semiconductor material body, a dielectric diaphragm above said channel for closing said channel, and heating elements for providing thermal energy to said channel, wherein said heating elements are arranged directly on said dielectric diaphragm;

and

analyzing a molecule in said biological sample.

20. The method of claim 19, wherein said molecule in said biological sample is DNA and said analyzing comprises amplification of said DNA to produce amplified DNA and detection of said amplified DNA.