Laser system and method for plating vias
AssigneeElectro Scientific Industries, Inc.
InventorMark D. Owen
Life of this patent
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Abstract
The output of a continuously pumped, Q-switched, Nd:YAG laser (10) is frequency converted to provide ultraviolet light (62) for plating internal wall surfaces (79, 126) of vias (72, 74) in multilayered electronic devices (80). The parameters of the output pulses (62) are selected to facilitate substantially uniform deposition of plating material particles explosively vaporized from a substrate (124) onto the internal wall surface (79, 126). These parameters typically include at least two of the following criteria: high average power of greater than about 100 milliwatts measured over the beam spot area, a temporal pulse width shorter than about 100 nanoseconds, a spot diameter of less than about 50 microns, and a repetition rate of greater than about one kilohertz.
Claims33
A method for plating an internal wall surface of a via through at least one layer of a device having multiple layers, comprising:
- generating a laser output of at least one pulse having a spot area, a wavelength shorter than about 400 nm, a temporal pulse width shorter than about 100 ns, and an average output power of greater than about 100 mW measured over the spot area;
- directing the laser output through the via toward a substrate having an electrically conductive plating material positioned in proximity to the internal wall surface of the via;
- and
- ablating the plating material from the substrate with a force sufficient to embed micrometer-sized particles of the plating material into the internal wall surface of the via in an amount sufficient to form an electrically conductive interconnection between the layers.
A method for laser processing a multilayered device including at least two layers having different chemical compositions, comprising:
- generating a first laser output having a spot area;
- applying the first laser output to the device so that the laser output removes at least two layers within the spot area to form a via having an internal wall surface, an open end, and an opposite end;
- generating a second laser output;
- directing the second laser output through the open end of the via toward a substrate having an electrically conductive material positioned across the opposite end of the via, the first and second laser outputs each including at least one pulse having a wavelength shorter than about 400 nm, a temporal pulse width shorter than about 100 ns, and an average output power of greater than about 100 mW measured over the spot area;
- and
- ablating the plating material from the substrate with a force sufficient to embed micrometer-sized particles of the plating material into the internal wall surface of the via in an amount sufficient to form a conductive interconnection between the layers.
Dependencies are inferred from the claim text.