Methods of fabricating micro-valves and jetting assemblies including such micro-valves
A method of constructing a micro-valve includes providing a substrate for an actuating beam of the micro-valve, the substrate including a first surface and a second surface. The method also includes forming a plurality of constituent layers on the first surface of the actuating beam, including a layer of piezoelectric material. The method also includes removing a portion of the substrate from at least one of the first surface or the second surface to define a cantilevered portion of the actuating beam. The method also includes providing an orifice plate including an orifice. The method also includes providing a valve seat on a surface of the orifice plate, the valve seat having an opening aligned with the orifice. The method also includes attaching the surface of the orifice plate to the second surface via an adhesive such that an overlapping portion of the cantilevered portion overlaps the orifice.
1. A method of constructing a jetting assembly, comprising:
forming a plurality of micro-valves on an orifice plate, wherein each of the micro-valves includes an actuating beam having a cantilevered portion;
providing an input fluid manifold including a first surface, a second surface, and a first opening extending from the first surface to the second surface;
attaching the first surface of the input fluid manifold to a device layer that includes the actuating beams such that some of the cantilevered portions of the actuating beams are aligned with the corresponding first opening, wherein the input fluid manifold and the plurality of micro-valves form a valve body, the valve body including a fluid reservoir defined in part by the first opening;
attaching a flex circuit to the second surface of the input fluid manifold, wherein the flex circuit includes a gap aligned with the first opening; and
attaching a carrier to the valve body.
2. The method of claim 1 , wherein each of the actuating beams comprises an electrical connection portion and a base portion extending from the electrical connection portion, wherein the cantilevered portion extends from the base portion, wherein the first opening comprises a rectangular channel, wherein the input fluid manifold comprises a second opening, the second opening extending substantially parallel to the first opening, wherein attaching the first surface of the input fluid manifold to the plurality of micro-valves is performed such that the second opening is aligned with at least some of the electrical connection portions.
3. The method of claim 2 , further comprising forming electrical connections between the electrical connection portions and the flex circuit via the second opening prior to attaching the carrier.
4. The method of claim 3 , further comprising depositing an encapsulant into the second opening such that the encapsulant covers the electrical connections.
5. The method of claim 2 , wherein attaching the first surface of the input fluid manifold to the device layer comprises:
forming a compartmentalized adhesive structure on the first surface of the input fluid manifold; and
attaching the device layer to the compartmentalized adhesive structure.
6. The method of claim 5 , wherein the carrier comprises a structural layer having a rigidity greater than a rigidity of the orifice plate, and wherein the method further comprises: disposing the carrier on the second surface of the fluid input manifold so as to couple the structural layer to the fluid input manifold.
7. The method of claim 6 , further comprising:
disposing a flex circuit in between the fluid input manifold and the carrier; and
coupling the flex circuit to each of the structural layer of the carrier and the fluid input manifold.
8. The method of claim 1 , further comprising:
providing an interposer having a rigidity greater than a rigidity of the orifice plate;
positioning a portion of the flex circuit on the second surface of the fluid input manifold;
positioning the interposer on the portion of the flex circuit; and
positioning the carrier on the interposer.
9. The method of claim 1 , wherein forming the plurality of micro-valves on the orifice plate comprises, for each micro-valve:
providing a substrate for the actuating beam of the micro-valve, the substrate including a first surface and a second surface;
forming a plurality of constituent layers of the actuating beam on the first surface, wherein the plurality of constituent layers include a layer of piezoelectric material; and
removing a portion of the substrate at the second surface to define the cantilevered portion.
10. The method of claim 9 , wherein forming the plurality of micro-valves on the orifice plate further comprises, for each micro-valve:
providing a valve seat on a surface of the orifice plate at an orifice in the orifice plate, wherein the valve seat comprises an opening aligned with the orifice; and
attaching the surface of the orifice plate to the second surface such that an overlapping portion of the cantilevered portion overlaps the orifice.
11. The method of claim 9 , wherein the substrate comprises a double silicon on insulator (SOI) wafer comprising:
a first silicon layer located between a first silicon dioxide layer and a second silicon dioxide layer, the first silicon dioxide layer defining the first surface,
a second silicon layer located between the second silicon dioxide layer and a third silicon dioxide layer, and
a base layer located adjacent to the third silicon dioxide layer on a side opposite the second silicon layer,
wherein the method further comprises removing the base layer such that the third silicon dioxide layer defines the second surface.
12. The method of claim 11 , wherein the removing a portion of the substrate comprises, for each micro-valve:
defining a perimetral shape of each of the actuating beam on the substrate from the first surface;
defining a sealing member and a spacer on the substrate from the second surface; and
releasing the actuating beam.
13. The method of claim 10 , wherein, for each micro-valve, the portion of the substrate is offset from an end of the substrate such that a sealing member is formed at an end of the cantilevered portion.
14. The method of claim 13 , wherein, for each micro-valve, the sealing member has a larger cross-sectional area than the orifice.
15. The method of claim 14 , wherein, for each micro-valve, the surface of the orifice plate is attached to the second surface such that the sealing member contacts the valve seat to close the opening.
16. The method of claim 9 , wherein forming the plurality of constituent layers on the first surface comprises, for each micro-valve:
depositing a barrier layer on the first surface;
depositing a first electrode on the barrier layer;
depositing the layer of piezoelectric material on the first electrode; and
depositing a second electrode on the layer of piezoelectric material.
17. The method of claim 16 , wherein forming the plurality of constituent layers of the actuating beam comprises, for each micro-valve, depositing a growth template layer on the first electrode prior to depositing the layer of piezoelectric material.