Polishing Piezoelectric Material
Devices having an actuator with polished piezoelectric material are described. Methods of forming a polished piezoelectric material include bonding a block of fired piezoelectric material onto a substrate and chemical mechanically polishing the block of fired piezoelectric material. The polished surface of the block of fired piezoelectric material can then be bonded to a device layer to form an actuator.
1 . A method for forming an assembly, comprising:
bonding a block of fired piezoelectric material onto a substrate; and
chemical mechanically polishing the block of fired piezoelectric material.
2 . The method of claim 1 , wherein the bonding includes applying a resin to one of the block of fired piezoelectric material or the substrate and bringing the block of fired piezoelectric material together with the substrate with the resin therebetween.
3 . The method of claim 1 , further comprising prior to chemical mechanically polishing the block, grinding away a portion of the thickness of the block.
4 . The method of claim 1 , wherein chemical mechanically polishing the block creates a surface with a surface roughness of between about 10 and 20 angstroms.
5 . The method of claim 1 , wherein chemical mechanically polishing the block of fired piezoelectric material forms a polished surface, the method further comprising:
forming an oxide layer on the polished surface;
activating the oxide layer to form an activated oxide layer;
activating a surface of a silicon or silicon oxide layer to form an activated device surface; and
bringing the activated oxide layer into contact with the activated device surface.
6 . The method of claim 5 , further comprising polishing the oxide layer prior to activating the oxide layer.
7 . The method of claim 5 , further comprising after bringing the activated oxide layer into contact with the activated device surface, heating the activated oxide layer and the activated device surface.
8 . The method of claim 7 , wherein heating includes heating to about 200° C.
9 . The method of claim 1 , wherein chemical mechanically polishing the block of fired piezoelectric material forms a polished surface, the method further comprising:
applying an electrode layer to the polished surface; and
bonding the electrode layer to a device surface.
10 . The method of claim 9 , wherein bonding the electrode layer to a device surface includes using a resin bonding material.
11 . The method of claim 9 , further comprising:
removing the substrate from the fired piezoelectric material to form an exposed piezoelectric material; and
chemical mechanically polishing the exposed piezoelectric material.
12 . The method of claim 1 , wherein bonding a block of fired piezoelectric material onto a substrate includes bonding the block of fired piezoelectric material onto a device substrate.
13 . The method of claim 12 , wherein the device substrate includes chambers adjacent but not open to the block of fired piezoelectric material.
14 . The method of claim 1 , wherein chemical mechanically polishing the block of fired piezoelectric material includes polishing away at least 4 microns of piezoelectric material.
15 . The method of claim 1 , wherein chemical mechanically polishing the block of fired piezoelectric material includes polishing away between about 4 and 10 microns of piezoelectric material.
16 . A method for forming an assembly, comprising:
forming an oxide layer on a piezoelectric material;
polishing the oxide layer;
after polishing the oxide layer, plasma activating the oxide layer; and
after the plasma activating step, contacting the oxide layer with a body, wherein the body includes silicon or silicon oxide.
17 . The method of claim 16 , further comprising heating the oxide layer and the body.
18 . A fluid ejection device, comprising:
a body having a chamber therein, the body formed of silicon; and
an actuator on the body and aligned with the chamber, wherein the actuator comprises piezoelectric material, the piezoelectric material having a surface roughness of less than 20 Angstroms, wherein the actuator is bonded to the body with a resin.
19 . The device of claim 18 , wherein the chamber in the body is in fluid communication with a nozzle.
20 . The device of claim 18 , wherein the actuator has a thickness of less than about 20 microns.
21 . The device of claim 18 , wherein the actuator has a thickness greater than 5 microns.
22 . The device of claim 18 , wherein the piezoelectric material does not include multiple layers.
23 . The device of claim 18 , wherein the piezoelectric material has a density of 7.5 g/cm 3 or more.
24 . The device of claim 18 , wherein the piezoelectric material has a density of about 8 g/cm 3 .
25 . The device of claim 18 , wherein the piezoelectric material has a d31 coefficient can be about 200 or greater.
26 . A fluid ejection device, comprising:
a body having a chamber therein, the body formed of silicon and having an upper layer of silicon or silicon oxide; and
an actuator on the body and aligned with the chamber, wherein the actuator comprises piezoelectric material, the piezoelectric material having a surface roughness of less than 20 Angstroms, wherein a layer of oxide is on the piezoelectric material and the layer of oxide is fusion bonded to the upper layer of the body.
27 . The device of claim 26 , wherein the chamber in the body is in fluid communication with a nozzle.
28 . The device of claim 26 , wherein the actuator has a thickness of less than about 20 microns.
29 . The device of claim 26 , wherein the actuator has a thickness greater than 5 microns.
30 . The device of claim 26 , wherein the piezoelectric material does not include multiple layers.
31 . The device of claim 26 , wherein the piezoelectric material has a density of 7.5 g/cm 3 or more.
32 . The device of claim 26 , wherein the piezoelectric material has a density of about 8 g/cm 3 .
33 . The device of claim 26 , wherein the piezoelectric material has a d31 coefficient can be about 200 or greater.