Soldering a flexible circuit
View Patent ↗Techniques are provided for controlling solder flow in applications where a flexible circuit is soldered to a microelectromechanical structure. A metal layer is formed on a substrate. A solder mask is formed on the metal layer such that portions of the metal layer are covered by the mask and portions are left exposed. A flexible circuit is soldered to the metal layer in at least some of the areas where the metal layer is exposed.
1. An actuator, comprising:
a first electrode;
a support substrate including piezoelectric material supporting the first electrode;
a mask formed on the first electrode, wherein the mask covers a first portion of the first electrode and overlies the length of a chamber adjacent to the support substrate; and
a solder material, wherein the solder material is supported by the first electrode and adjacent to a second portion of the first electrode, wherein the first portion of the first electrode does not overlap the second portion of the first electrode and the mask includes a material that is substantially non-wettable by the solder material when melted.
2. The actuator of claim 1 , wherein:
the mask includes an oxide material.
3. The actuator of claim 1 , further comprising:
a second electrode, wherein the solder material electrically connects the first and second electrodes to an integrated circuit.
4. The actuator of claim 1 , further comprising:
a flexible circuit, wherein the solder material electrically connects the flexible circuit to the first electrode.
5. The actuator of claim 1 , wherein:
the mask is between about 0.1 and about 2 microns thick.
6. The actuator of claim 5 , wherein:
the mask is about 0.5 microns thick.
7. The actuator of claim 1 , further comprising:
a second electrode adjacent to the first electrode; and
an electrode separation gap defined by a space that separates the first and second electrodes, the mask being in the electrode separation gap.
8. A printhead, comprising:
a substrate in which flow path features are formed, the flow path features including a pumping chamber and a nozzle; and
a first actuator bonded to the substrate, the first actuator comprising:
a piezoelectric layer;
a first electrode supported by the piezoelectric layer;
a mask formed on the first electrode, wherein the mask covers a first portion of the first electrode and the mask overlies the length of the pumping chamber; and
a solder material, wherein the solder material is supported by the first electrode and adjacent to a second portion of the first electrode, wherein the first portion of the first electrode does not overlap the second portion of the first electrode and the mask includes a material that is substantially non-wettable by the solder material when the solder material is melted.
9. The printhead of claim 8 , further comprising:
a second electrode, wherein the substrate is closer to the second electrode than the first electrode.
10. The printhead of claim 9 , wherein:
an electrode separation gap defined by a space separates the first and second electrodes, and the mask is in the electrode separation gap.
11. The printhead of claim 8 , wherein:
the mask is between about 0.1 and about 2 microns thick.
12. The printhead of claim 11 , wherein:
the mask is about 0.5 microns thick.
13. The printhead of claim 8 , wherein:
the mask includes an oxide.
14. The printhead of claim 8 , further comprising:
a second actuator bonded to the substrate and adjacent to the first actuator; and
a kerf defined by a space that separates the first and second actuators, the mask being in the kerf.