Browse Prior Art Database

Fabricating a Monolithic Structure for Electrostatic Drop Synchronization

IP.com Disclosure Number: IPCOM000086961D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Baran, EF: AUTHOR [+3]

Abstract

In ink jet printing the conventional method of generating drops from the jet of liquid is by a piezoelectric driver which is closely coupled to the nozzle. In electrostatic drop synchronization (EDS) the piezoelectric driver is replaced by an electrode located very close to the exit side of the nozzle. The drops are formed by applying an AC signal with or without a DC bias to the electrode. EDS offers better performance, potential suitability for integration with active electronic devices and low cost.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Fabricating a Monolithic Structure for Electrostatic Drop Synchronization

In ink jet printing the conventional method of generating drops from the jet of liquid is by a piezoelectric driver which is closely coupled to the nozzle. In electrostatic drop synchronization (EDS) the piezoelectric driver is replaced by an electrode located very close to the exit side of the nozzle. The drops are formed by applying an AC signal with or without a DC bias to the electrode. EDS offers better performance, potential suitability for integration with active electronic devices and low cost.

An actual process used in fabricating nozzles with doped polycrystalline silicon (poly-Si), including a synchronization electrode, is described below. The process can be varied widely with respect to film thickness and type and sequence of fabrication steps.

Referring to Fig. 1(a), silicon wafer 2 of (100) orientation was cleaned and thermally oxidized forming an SiO(2) layer 4 on each face. A silicon nitride Si(3)N(4) film 6 was deposited by chemical vapor deposition (CVD) followed by CVD poly-Si 8. The Si(3)N(4) film is not essential and can be omitted entirely. However, it is useful in some structures requiring extremely small and well controlled electrode-to-orifice spacing.

Referring to Fig. 1(b), the poly-Si layer was heavily doped with phosphorus from a phosphorus oxychloride (POCl(3)) source, then thermally oxidized to grow an SiO(2) film 10 on the poly-Si. Ptype instead of n+ type doping is equally feasible. A photoresist film 12 was then applied on each face. By photolithography the base hole pattern 14 of the nozzle array was defined on the back of the wafer.

Referring to Fig. 1(c), the silicon substrate was etched anisotropically through the entire wafer thickness. The SiO(2) was stripped completely from the front and back with buffered hydrofluoric acid, leaving a membrane of n...