Process for manufacturing integrated chemical microreactors of semiconductor material

• US 20020017660A1
• Filed: 06/04/2001
• Published: 02/14/2002
• Est. Priority Date: 06/05/2000
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Villa, Flavio, Barlocchi, Gabriele, Mastromatteo, Ubaldo, Cattaneo, Mauro
• Granted Patent: US 6,710,311 B2
• Time in Patent Office: Days
• US Class Current: 257/216
• CPC Class Codes: B01J 19/0093 Microreactors, e.g. miniaturised or microfabricated reactors laboratory containers with capillary fluid transport in microfabricated channels or chambers B01L3/5027
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2300/185 using a liquid as fluid
• CPC Class Codes: B01L 2300/1883 using thermal insulation
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• 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
• CPC Class Codes: B01L 7/525 with physical movement of samples between temperature zones
• CPC Class Codes: B81B 2201/0214 Biosensors; Chemical sensors
• CPC Class Codes: B81B 2201/051 Micromixers, microreactors
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2203/0338 Channels
• CPC Class Codes: B81C 1/00119 Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: B81C 2201/053 Depositing a protective layers

Abstract

The microreactor is completely integrated and is formed by a semiconductor body having a surface and housing at least one buried channel accessible from the surface of the semiconductor body through two trenches. A heating element extends above the surface over the channel and a resist region extends above the heating element and defines an inlet reservoir and an outlet reservoir. The reservoirs are connected to the trenches and have, in cross-section, a larger area than the trenches. The outlet reservoir has a larger area than the inlet reservoir. A sensing electrode extends above the surface and inside the outlet reservoir.

Claims

1. An integrated microreactor comprising:

a semiconductor material body having a surface;

a buried channel extending in said semiconductor material body at a distance from said surface, and having a first and a second ends;

first and second trenches extending from said surface respectively as far as said first and second ends of said buried channel, and being in fluid connection with said buried channel; and

a reservoir region, extending above said surface and defining a first and a second reservoirs connected to said first and second trenches.

2. The integrated microreactor of claim 1, wherein said first and second reservoir have, in cross section, larger areas than said first and second trenches.

3. The integrated microreactor according to claim 1, wherein said second reservoir has a larger area than said first reservoir, and said integrated microreactor comprises a sensing electrode structure extending above said surface and inside said second reservoir.

4. The integrated microreactor according to claim 1 further comprising a heating element arranged between said surface and said reservoir region, above said buried channel.

5. The integrated microreactor according to claim 4, further comprising an insulating material region extending between said surface and said reservoir region and surrounding said heating element.

6. The integrated microreactor according to claim 5, further comprising a protective region arranged between said insulating material region and said reservoir region.

7. The integrated microreactor according to claim 6, wherein the reservoir region is of a first resist and the protective region is of a second resist, and in that one of said first and second resists is of a negative type, and the other of said first and second resists is of a positive type.

8. The integrated microreactor according to claim 1, wherein the reservoir region is of a first resist.

9. The integrated microreactor according to claim 8 wherein said first resist is SU8.

10. The integrated microreactor according to claim 8, wherein said first resist is a photosensitive dry resist.

11. A structure comprising:

a semiconductor material body;

a buried channel formed in the semiconductor material body and at a distance from the surface of the semiconductor material body.

a first reservoir, formed on the surface of the semiconductor material body;

a first trench, formed on the semiconductor material body, extending from the first reservoir to a first end of the buried channel;

a second trench formed on the semiconductor material body, extending from the surface of the semiconductor material body to a second end of the buried channel; and

a heating element, formed on the semiconductor material body adjacent to the buried channel.

12. The structure of claim 11, further comprising a second reservoir, formed on the surface of the semiconductor material body, where the second trench extends from the second reservoir on the surface of the semiconductor material body to a second end of the buried channel.

13. The structure of claim 11, further comprising a sensing electrode structure, formed on the semiconductor material body.

14. The structure of claim 12, further comprising a sensing electrode structure, formed on the semiconductor material body and inside the second reservoir.

16. The process according to claim 15, wherein, before said step of forming first and second reservoirs, the step is carried out of forming a heating element surrounded by an insulating layer and extending above said surface, over said buried channel.

17. The process according to claim 16, wherein said step of forming first and second reservoirs is carried out before said step of forming first and second trenches.

18. The process according to claim 17, wherein, before said step of forming first and second reservoirs, the following step is carried out:

forming a protective layer above said surface;

and, after said step of forming first and second reservoirs, the following steps are carried out;

selectively removing said protective layer as far as said surface, above said ends of said buried channel, to form first and second openings; and

digging said first and said second trenches, in an aligned way to said first and second openings.

19. The process according to claim 18, wherein said protective layer comprises a second resist, and one of said first and second resists is of a negative type, and the other of said first and second resists is of a positive type.

20. The process according to claim 15, wherein said first resist is SU8.

21. The process according to claim 15, wherein said step of forming first and second reservoirs is carried out after said step of forming first and second trenches.

22. The process according to claim 21, wherein, before said step of forming first and second reservoirs, the following steps are carried out:

forming a protective layer above said surface;

selectively removing said protective layer as far as said surface, above said ends of said buried channel, to form first and second openings; and

digging said first and second trenches in an aligned way to said first and second openings.

23. The process according to claim 15, wherein said first resist is a photosensitive dry resist.

24. The process according to claim 19, wherein said step of forming first and second reservoirs comprises the following steps:

applying a reservoir layer by lamination and thermocompression; and

selectively removing said reservoir layer.

26. The method of claim 25 wherein the heating step is performed by:

passing an electric current through a heating element arranged in the semiconductor material body on top of the buried channel.

27. The method of claim 25, further including the step of extracting the fluid from the buried channel into a second reservoir via a second trench, the second reservoir and second trench being integrated in the semiconductor body, the second trench extending from the second reservoir on the surface of the semiconductor material body as far as a second end of the buried channel.

28. The method of claim 25, further including the step of detecting a desired product within the fluid, where the detection step is performed by the use of a sensing electrode structure, the sensing electrode structure being integrated in the semiconductor material body and in contact with the fluid.

29. The method of claim 24 wherein the first and second reservoirs are formed in, and defined by a resist layer formed on the surface of the semiconductor material body.

30. The method according to claim 25 further including:

repeating the heating and cooling steps a plurality of times to achieve a desired reaction in biological matter within the fluid.

31. The method according to claim 25, wherein the cooling step is carried out by:

terminating the heating of the fluid; and

permitting the fluid to cool towards the ambient.

32. The method according to claim 25, wherein the cooling step is carried out by:

terminating the heating of the fluid; and

drawing heat from the fluid using a heat transfer mechanism.

15. A process for the fabrication of an integrated microreactor, comprising:

forming a semiconductor material body having a surface and a buried channel extending at a distance from said surface and having first and second ends;

forming first and second trenches extending from said surface as far as, respectively, said first and said second ends of said buried channel and being in fluid connection with said buried channel; and

above said surface, forming first and second reservoirs respectively connected to said first and second trenches in a reservoir layer of a first resist.

25. A method, comprising:

introducing a fluid from a first reservoir into a first trench, the first reservoir and first trench being integrated in a semiconductor body;

introducing the fluid from the first trench into a buried channel, the buried channel extending in a semiconductor material body at a distance from a surface of the semiconductor material body, the first trench extending from the reservoir on the surface of the semiconductor material body to a first end of the buried channel;

heating the fluid within the buried channel; and

cooling the fluid within the buried channel.