Microfluidic substrates having improved fluidic channels

• US 7,438,392 B2
• Filed: 11/17/2005
• Issued: 10/21/2008
• Est. Priority Date: 11/04/2003
• Status: Expired due to Term

• Current Assignee: Funai Electric Co., Ltd. (Funai Electric Holdings Company Limited)
• Original Assignee: Lexmark International Incorporated (Ninestar Corporation)
• Inventors: Vanderpool, Jason T., Mrvos, James M., Vaideeswaran, Karthik, Patil, Girish S., Warner, Richard L., McNees, Andrew L., Krawczyk, John W., Doerre, Mark L.
• Primary Examiner(s): Nguyen; Lamson D.
• Application Number:
  US11/281,090
• Publication Number:
  US 20060077221A1
• Time in Patent Office: 1,069 Days
• Field of Search: 347/40, 347/43, 347/65, 438/8, 438/49, 438/85, 438/99, 438/494
• US Class Current: 347/65
• CPC Class Codes: B41J 2/14145 Structure of the manifold
• CPC Class Codes: B41J 2/1603 of the front shooter type
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering

Abstract

A method for improving fluidic flow for a microfluidic device having a through hole or slot therein. The method includes the steps of forming one or more openings through at least part of a thickness of a substrate from a first surface to an opposite second surface using a reactive ion etching process whereby an etch stop layer is applied to side wall surfaces in the one or more openings during alternating etching and passivating steps as the openings are etched through at least a portion of the substrate. Substantially all of the etch stop layer coating is removed from the side wall surfaces by treating the side wall surfaces using a method selected from chemical treatment and mechanical treatment, whereby a surface energy of the treated side wall surfaces is increased relative to a surface energy of the side wall surfaces containing the etch stop layer coating.

Claims

1. A semiconductor substrate for an ink jet printhead, the substrate comprising a first surface, a second surface opposite the first surface, and one or more ink feed ports therein extending from the first surface to the second surface, the one or more ink feed ports are formed at least in part by a reactive ion etching process and having side wall surfaces having a water contact angle of less than about ninety degrees for improved ink flow through the one or more ink feed ports.

2. The semiconductor substrate of claim 1 wherein the ink feed ports formed by a reactive ion etching process have side wall surfaces having an initial water contact angle of greater than about ninety degrees prior to treating the ink feed ports by a chemical or mechanical treatment method and have side wall surfaces having a water contact angle of less than about ninety degrees after treating the ink feed ports with a chemical or mechanical treatment method.

3. The semiconductor substrate of claim 2 wherein the initial water contact angle of the side wall surfaces of the ink feed ports is provided by a passivating layer coating derived from a fluorinated C₂ to C₄ compound.

4. The semiconductor substrate of claim 3 wherein the water contact angle of less than about ninety degrees is provided by side wall surfaces of the ink feed ports that are substantially devoid of the passivating layer coating.

5. The semiconductor substrate of claim 1 wherein the water contact angle of less than about ninety degrees is provided by the side wall surfaces of the ink feed ports substantially devoid of a passivating layer coating formed on the side wall surfaces during the reactive ion etching process for forming the ink feed ports.

6. The semiconductor substrate of claim 1 wherein the substrate comprises a silicon semiconductor substrate.

7. An ink jet printhead comprising the semiconductor substrate of claim 1.

8. A silicon substrate for a micro-fluid ejection device, the substrate comprising a first surface, a second surface opposite the first surface, and one or more fluid feed ports therein extending from the first surface to the second surface, the one or more fluid feed ports are formed at least in part by a reactive ion etching process and having side wall surfaces having a water contact angle surface energy providing improved fluid flow through the one or more fluid feed ports, wherein the water contact angle is less than about ninety degrees.

9. The silicon substrate of claim 8 wherein the fluid feed ports formed by a reactive ion etching process have side wall surfaces having a first water contact angle surface energy prior to treating the fluid feed ports by a chemical or mechanical treatment method and have side wall surfaces having a second water contact angle surface energy greater than the first water contact angle surface energy after treating the fluid feed ports with a chemical or mechanical treatment method.

10. The silicon substrate of claim 9 wherein the first water contact angle surface energy of the side wall surfaces of the fluid feed ports is provided by a passivating layer coating derived from a fluorinated C₂ to C₄ compound.

11. The silicon substrate of claim 10 wherein the second water contact angle surface energy is provided by side wall surfaces of the fluid feed ports that are substantially devoid of the passivating layer coating.

12. The silicon substrate of claim 8 wherein the second water contact angle surface energy is provided by the side wall surfaces of the fluid feed ports substantially devoid of a passivating layer coating formed on the side wall surfaces during the reactive ion etching process for forming the fluid feed ports.

13. The silicon substrate of claim 8 wherein the substrate comprises a semiconductor substrate.

14. A substrate for a micro-fluid ejection device, the substrate comprising a first surface, a second surface opposite the first surface, and one or more fluid ports therein extending from the first surface to the second surface, the one or more fluid feed ports are formed at least in part by a reactive ion etching process and having side wall surfaces having improved wettability for improved fluid flow through the one or more fluid feed ports, wherein the wall surfaces have a water contact angle of less than about ninety degrees.

15. The substrate of claim 14 wherein the fluid feed ports formed by a reactive ion etching process have side wall surfaces having a first wettability prior to treating the fluid feed ports by a chemical or mechanical treatment method and have side wall surfaces having a second wettability greater than the first wettability after treating the fluid feed ports with a chemical or mechanical treatment method.

16. The substrate of claim 15 wherein the first wettability of the side wall surfaces of the fluid feed ports is provided by a passivating layer coating derived from a fluorinated C₂ to C₄ compound.

17. The substrate of claim 16 wherein the second wettability is provided by side wall surfaces of the fluid feed ports that are substantially devoid of the passivating layer coating.

18. The substrate of claim 14 wherein the improved wettability is provided by the side wall surfaces of the fluid feed ports substantially devoid of a passivating layer coating formed on the side wall surfaces during the reactive ion etching process for forming the fluid feed ports.

19. The substrate of claim 14 wherein the substrate comprises a silicon substrate.

20. The substrate of claim 19, wherein the silicon substrate comprises a silicon semiconductor substrate.