Micromachined fluidic device and method for making same

• US 7,005,078 B2
• Filed: 05/25/2001
• Issued: 02/28/2006
• Est. Priority Date: 05/25/2000
• Status: Expired due to Term

• Current Assignee: Debiotech S.A.
• Original Assignee: Debiotech S.A.
• Inventors: Gamper, Stephan, Van Lintel, Harald T., Maillefer, Didier
• Primary Examiner(s): Vinh, Lan
• Application Number:
  US10/296,466
• Publication Number:
  US 20040052657A1
• Time in Patent Office: 1,740 Days
• Field of Search: 216/2, 216/27, 216/41, 216/56, 216/80, 216/97, 216/95, 438/21, 438/49, 438/51, 438/52, 438/53, 438/745
• US Class Current: 216/27
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: F04B 43/043 Micropumps

Abstract

The fluid-flow device (100) of the invention comprises a stack (30) covered by a closure wafer (20), said stack (30) comprising a support wafer (36), a layer of insulating material (34), and a silicon layer (32). The closure wafer (20) and/or said silicon layer (32) are machined so as to define a cavity (38) between said closure wafer (20) and said silicon layer (32), said support wafer (36) has at least one duct (102) passing right through it, said layer of insulating material (34) presenting at least one zone (35) that is entirely free of material placed at least in line with said duct (102) so as to co-operate with said cavity (38) to define a moving member (40) in said silicon layer (32), the moving member being suitable under the pressure of liquid in said cavity (38) for reversibly moving towards said support wafer (36) until contact is made between said moving member (40) and said support wafer (36).

Claims

1. A method of manufacturing a fluid-flow device, the method comprising the following steps:

providing a stack (30) comprising a support wafer (36), one layer of insulating material (34) covering directly at least part of said support wafer (36), and one layer of single-crystal or polycrystalline silicon (32);

covering directly said layer of insulating material (34) and presenting a free face;

providing at least one closure wafer (20);

using photolithography and chemical etching to machine a cavity (38) from said closure wafer (20) and/or from the free face of said silicon layer (32);

using photolithography and chemical etching to machine at least one duct (102) passing right through said support wafer (36);

chemically etching said layer of insulating material (34) at least via said duct (102) such that a zone (35) of said silicon layer (32) is freed from said layer of insulating material (34), thereby forming a moving member (40) in said silicon layer (32), said moving member (40) remaining connected to the silicon layer (32) and facing said freed zone (35);

using a physicochemical method to connect said closure wafer (20) in leaktight manner directly to said free face of silicon layer (32) thereby said moving member (40) facing said cavity (38).

2. Method according to claim 1, wherein said support wafer (36) is made of silicon.

3. Method according to claim 1, wherein said insulating material (34) is made of silicon oxide.

4. Method according to claim 1, wherein said physicochemical method is a wafer bonding technique.

5. A method of manufacturing a liquid inlet control member 100, the method comprising the steps of:

providing a stack (30) that comprises a support wafer (36), one insulating material layer 34

covering directly at least part of the support wafer (36), and one layer of silicon (32) covering directly the insulating material layer (34) and presenting a gee face opposite from its face covering said layer (34) of insulating material;

machining a cavity (38) from the free face of the silicon layer (32) by photolithography and chemical etching;

machining a gap (104) from the free face of the silicon layer (32) by photolithography and chemical etching through the entire thickness of the silicon layer (32) until the layer (34) of insulating material is reached;

from the other side of the stack (30), machining a liquid inlet duct (102) passing right through the support wafer (36) by photolithography and chemical etching;

chemically etching the insulating material layer (34) through the duct (102) and the gap (104) so as to create a zone (35) that is freed from material in the insulating material layer (34) so that the zone of the silicon layer (32) situated facing said zone (35) is freed of the layer (34) of insulating material, thus forming the moving member (40) in said silicon layer (32), which moving member (40) remains connected to the silicon layer (32) by arm(s) (41) and faces said freed zone (35);

providing a closure wafer (20); and

using physicochemical means to connect the closure wafer (20) in leaktight manner directly to said free face of the silicon layer (32).

6. Method according to claim 5, wherein said support wafer (36) is made of silicon.

7. Method according to claim 5, wherein said insulating material (34) is made of silicon oxide.

8. Method according to claim 5, wherein said physicochemical method is a wafer bonding technique.

9. A method of manufacturing a liquid pressure detector member 400, the method comprising the steps of:

providing a stack (30) comprising a support wafer (36), one insulating material layer (34) covering directly at least part of the support wafer (36), and one layer (32) of silicon covering directly the insulating material layer (34) and presenting a free face opposite from a face covering the insulating material layer (34);

machining a cavity (38) from the free face of the silicon layer (32) by photolithography and chemical etching;

from the other side of the stack (30), machining at least two ducts (412) and (412′

) passing right through the support wafer (36);

subjecting the insulating material layer (34) to chemical etching via the ducts (412) and (412′

) so as to form a zone (35) in the insulating material layer (34) that is free from material, while leaving insulating material in the fraction (416) so as to release a moving member (40) from the insulating material layer (34), said moving member (40) remaining connected to the silicon layer 32 and facing said freed zone;

providing a closure wafer (20), and

using a physicochemical method for connecting the closure wafer (20) in leaktight manner directly to said freed face of the silicon layer (32).

10. Method according to claim 9, wherein said support wafer (36) is made of silicon.

11. Method according to claim 9, wherein said insulating material (34) is made of silicon oxide.

12. Method according to claim 9, wherein said physicochemical method is a wafer bonding technique.

13. A method of manufacturing a micropump (500), the method comprising the steps of:

providing a stack (30) comprising a support wafer (36), one layer of insulating material (34) and covering directly at least part of the support wafer (36), and one layer (32) of silicon covering directly the layer (34) of insulating material and presenting a free face opposite a face covering the layer (34) of insulating material;

by means of photolithography and chemical etching from the free face of the support wafer (36), machining the following;

one liquid inlet duct (102) of the inlet control member (100), an annular volume (508), at least two ducts (412) and (412′

) of a pressure detector (400), and a liquid outlet duct of a liquid outlet control member (200), these ducts or annular volume passing right through the support wafer (36);

by means of photolithography and chemical etching, from the other side of the stack (30), that is, from the free face of the silicon layer (32), machining the following;

a gap (104) and a first cavity (381) of the inlet control member (100), a pump chamber (504), a second cavity (384) of the pressure detector (400), a third cavity (382), and an orifice (308) of the liquid outlet control member (200);

subjecting the insulating material layer (34) to chemical etching via the liquid inlet duct (102) of the inlet control member (100), via the annular volume (508), via the ducts (412) and (412′

) of the pressure detector (400), and via the liquid outlet duct (204) of the liquid outlet control member (200) so as to form zones (351), (535), (354) and (352) of the insulating material layer (34) that are free from material, thus making it possible to release the following moving members respectively from the insulating material layer (34);

a first moving member (401), a diaphragm (506), a second moving member (404), and a third moving member (402), said moving members remaining connected to the silicon layer (32) and respectively facing one of freed zones (351), (535), (354) and (352) of the insulating material layer (34);

providing a first closure wafer (20);

depositing a layer of anti-adhesion material by a physicochemical method on a face (20a) of the first closure wafer (20) that is to be connected to said stack (30), the layer of anti-adhesion material being structured as to form elements (510) and an anti-adhesion layer (210);

providing a second closure wafer (20′

)

depositing another layer of anti-adhesion material by a physicochemical method on a face of the second closure wafer (20′

) that is to be connected to said stack (30), said layer of anti-adhesion material being structured so as to form a ring-shaped layer (520);

directly connecting the first closure wafer (20) in leaktight manner by a physicochemical method to the free face of the silicon layer (32); and

connecting the second closure wafer (20′

) in leaktight manner by a physicochemical method to the surface of the support wafer (36) that is not covered by the layer of insulating material (34).

14. Method according to claim 13, wherein said support wafer (36) is made of silicon.

15. Method according to claim 13, wherein said insulating material (34) is made of silicon oxide.

16. Method according to claim 13, wherein said physicochemical method is a wafer bonding technique.

17. Method according to claim 13, wherein said anti-adhesion material is made of titanium.