Bonded silicon structure for high density print head
View Patent ↗A print head including a jet stack can be formed using semiconductor device manufacturing techniques. A blanket metal layer, a blanket piezoelectric element layer, and a blanket conductive layer can be formed over a semiconductor substrate such as a semiconductor wafer or wafer section. The piezoelectric element layer and the blanket conductive layer can be patterned to provide a plurality of transducer piezoelectric elements and top electrodes respectively, while the metal layer forms a bottom electrode for the plurality of transducers. Subsequently, the semiconductor substrate can be patterned to form a body plate for the print head jet stack. Forming a print head jet stack using semiconductor device manufacturing techniques can provide a high resolution device with small feature sizes.
1. A print head jet stack comprising a plurality of transducers, wherein the print head jet stack comprises:
a semiconductor substrate body plate;
a diaphragm overlying the semiconductor substrate body plate;
a patterned piezoelectric layer overlying the diaphragm;
a first patterned conductive layer overlying the patterned piezoelectric layer, wherein the diaphragm comprises a conductive bottom electrode of the plurality of transducers, the patterned piezoelectric layer comprises a plurality of piezoelectric elements for the plurality of transducers, wherein each piezoelectric element is separated from an adjacent piezoelectric element by a space, and the first patterned conductive layer comprises a plurality of top electrodes for the plurality of transducers;
a dielectric interstitial layer interposed directly between adjacent transducers of the plurality of transducers, wherein the dielectric interstitial layer physically contacts the diaphragm and the patterned piezoelectric layer, fills the space between each adjacent piezoelectric element from the diaphragm to an upper surface of the first patterned conductive layer, comprises a planar upper surface, and overlies a portion of the first patterned conductive layer;
a second patterned conductive layer that physically contacts the planar upper surface of the dielectric interstitial layer, wherein a portion of the dielectric interstitial layer is directly interposed between the first patterned conductive layer and the second patterned conductive layer in a direction perpendicular to the diaphragm, the second patterned conductive layer comprising:
a plurality of first pads that overlie and physically and electrically contact the plurality of top electrodes, and physically contact the planar upper surface of the interstitial dielectric layer;
a plurality of traces electrically coupled to the plurality of first pads that physically contact the planar upper surface of the interstitial dielectric layer;
a plurality of second pads electrically coupled to the plurality of traces and to the plurality of first pads, wherein the plurality of second pads are each laterally located with respect to the patterned piezoelectric layer; and
an application specific integrated circuit (ASIC) electrically coupled to each of the plurality of second pads.
2. The print head jet stack of claim 1 , wherein the semiconductor substrate body plate comprises an etched semiconductor wafer section.
3. The print head jet stack of claim 1 , wherein the diaphragm is at least one of a chemical vapor deposition (CVD) metal and a sputtered metal.
4. The print head jet stack of claim 1 , further comprising:
an etch stop layer interposed between the diaphragm and the semiconductor substrate body plate.
5. The print head jet stack of claim 1 , wherein the first conductive layer and the second conductive layer are each one of a chemical vapor deposition (CVD) metal and a sputtered metal.
6. The print head jet stack of claim 5 , further comprising:
an application specific integrated circuit (ASIC) flip-chip mounted to the semiconductor substrate and to the plurality of second pads, and electrically coupled with the plurality of top electrodes for the plurality of transducers through the plurality of second pads.
7. A printer, comprising:
a print head comprising a print head jet stack, the print head jet stack comprising:
a plurality of transducers;
a semiconductor substrate body plate;
a diaphragm overlying the semiconductor substrate body plate;
a patterned piezoelectric layer overlying the diaphragm;
a first patterned conductive layer overlying the patterned piezoelectric layer, wherein the diaphragm comprises a conductive bottom electrode of the plurality of transducers, the patterned piezoelectric layer comprises a plurality of piezoelectric elements for the plurality of transducers, wherein each piezoelectric element is separated from an adjacent piezoelectric element by a space, and the first patterned conductive layer comprises a plurality of top electrodes for the plurality of transducers;
a dielectric interstitial layer comprising a material selected from the group consisting of polyimide, polymer, silicon dioxide, photosensitive epoxy, and photoresist interposed directly between adjacent transducers of the plurality of transducers, wherein the dielectric interstitial layer physically contacts the diaphragm and the patterned piezoelectric layer, fills the space between each adjacent piezoelectric element from the diaphragm to an upper surface of the first patterned conductive layer, comprises a planar upper surface, and overlies a portion of the first patterned conductive layer;
a second patterned conductive that layer physically contacts the planar upper surface of the dielectric interstitial layer, wherein a portion of the dielectric interstitial layer is directly interposed between the first patterned conductive layer and the second patterned conductive layer in a direction perpendicular to the diaphragm, the second patterned conductive layer comprising:
a plurality of first pads that overlie and physically and electrically contact the plurality of top electrodes, and physically contact the planar upper surface of the interstitial dielectric layer;
a plurality of traces electrically coupled to the plurality of first pads that physically contact the planar upper surface of the interstitial dielectric layer; and
a plurality of second pads electrically coupled to the plurality of traces and to the plurality of first pads, wherein the plurality of second pads are each laterally located with respect to the patterned piezoelectric layer;
an application specific integrated circuit (ASIC) electrically coupled to each of the plurality of second pads; and
a printer housing which encloses the print head.
8. The printer of claim 7 , wherein the semiconductor substrate body plate comprises an etched semiconductor wafer section.
9. The printer of claim 7 , wherein the diaphragm is at least one of a chemical vapor deposition (CVD) metal and a sputtered metal.
10. The printer of claim 7 , wherein the print head jet stack further comprises:
an etch stop layer interposed between the diaphragm and the semiconductor substrate body plate.
11. The printer of claim 7 , wherein the first conductive layer and the second conductive layer are each one of a chemical vapor deposition (CVD) metal and a sputtered metal.
12. The printer of claim 11 , further comprising:
an application specific integrated circuit (ASIC) flip-chip mounted to the semiconductor substrate and to the plurality of second pads, and electrically coupled with the plurality of top electrodes for the plurality of transducers through the plurality of second pads.
13. The print head jet stack of claim 1 , wherein the dielectric interstitial layer comprises a material selected from the group consisting of polyimide, polymer, silicon dioxide, photosensitive epoxy, and photoresist.