International Business Machines Corporation

Richard Kachmarik

Patrick Lamey

Leonard T Olson

Francis D Austin

An optoelectronic package with direct free space optical communication between pairs of optical transmitters and receivers located on different substrate surfaces in a closely spaced stack of chip carrying substrates is disclosed. The transmitters and receivers are aligned so that a light beam from each transmitter follows an optical path toward its respective receiver. In the stack of substrates, the transmitters and receivers are mounted on the surfaces of the substrates, many of which are separated by intervening substrates. These intervening substrates have vias, holes or transparent regions, or other optical means, at locations along the optical paths connecting the transmitters and receivers. Lenses or other concentrating means, where required, are adjacent to a transmitter so that its diverging light is focused on the intended receiver. Substrates are aligned so that the light from transmitters shines through the optical means in intervening substrates to the receivers. Means for removing heat from the substrates are included.

High speed optical interconnect

A method to integrate thermal drop on demand ink jet devices and related pulse driver circuitry for chips used in thermal ink jet printers. This integrated printhead chip is made by first fabricating on the substrate the driver pulse circuitry through the last level of metallization. Once complete, a low temperature (&lt;400 C) CVD oxide is deposited and planarized. It is of sufficient thickness (3 to 4 microns) to insure a good thermal barrier between the pulse circuitry and the thermal inkjet devices. After planarization, the resistor material is deposited and patterned. Openings are then patterned to the inputs and outputs of the pulse driver circuitry. Aluminum copper metallurgy is deposited and patterned to connect the resistor to the pulse driver output and define the heater resistor areas. Inorganic and organic barrier layers are applied and patterned to protect the resistor material and interconnecting metallurgy from the corrosive effects of the ink. After testing, ink holes are drilled and the wafer is diced and nozzle plates are attached to the chips. Thus, this 'on chip' driver integration enables the pulse driver circuitry to be moved to the thermal ink jet printhead. It offers advantages over other methods of ink jet/driver device integration by the chip footprint the same without decreasing the dimensions of the respective devices.

Method to integrate drive/control devices and ink jet on demand devices

This application discloses a novel method to integrate thermal drop on demand ink jet devices and related pulse driver circuitry for chips used in thermal ink jet printers. This integrated printhead chip is made by first fabricating on the substrate the driver pulse circuitry through the last level of metallization. Once complete, a low temperature (&lt;400 C.) CVD oxide is deposited and planarized. It is of sufficient thickness (3 to 4 microns) to insure a good thermal barrier between the pulse circuitry and the thermal inkjet devices. After planarization, the resistor material is deposited and patterned. Openings are then patterned to the inputs and outputs of the pulse driver circuitry. Aluminum copper metallurgy is deposited and patterned to connect the resistor to the pulse driver output and define the heater resistor areas. Inorganic and organic barrier layers are applied and patterned to protect the resistor material and interconnecting metallurgy from the corrosive effects of the ink. After testing, ink holes are drilled and the wafer is diced and nozzle plates are attached to the chips. Thus, this 'on chip' driver integration enables the pulse driver circuitry to be moved to the thermal ink jet printhead. It offers advantages over other methods of ink jet/driver device integration by the chip footprint the same without decreasing the dimensions of the respective devices.

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Bealeton, VA, United States of America

Richard Kachmarik