Browse Prior Art Database

Controlling Sidewall Angle on Laser Ablated Holes

IP.com Disclosure Number: IPCOM000108180D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 62K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+4]

Abstract

Disclosed is a method of control of the sidewall angle in laser ablated polymers to ensure good contact of deposited metallurgy.

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This is the abbreviated version, containing approximately 100% of the total text.

Controlling Sidewall Angle on Laser Ablated Holes

      Disclosed is a method of control of the sidewall angle in laser
ablated polymers to ensure good contact of deposited metallurgy.

      The multilayer dielectric coating of the projection mask can be
thinned in a controlled manner near the edges of the features on the
mask.  A silylated novalack photoresist 1 and dissolvable polyimide
lift off mask 2 formed on a fused silica substrate 3 will be used as
a deposition mask in the electron beam evaporation system used to
deposit the multilayer dielectric film 4.  The overhang 5 sketched in
the figure is necessary to prevent deposition on the sidewalls of the
etched out region.  However, if the background pressure in the
deposition system is raised, scattering will leave some deposition
outside of the line of sight.  The reflectivity of the film in the
shadow region will not be as high as in the center of the feature.
By controlling the background pressure, the thickness of the layers
as a function of the distance to the edge of the feature can be
controlled, and hence the reflectivity.  Now, when the mask is
focussed on the part to be laser ablated, the fluence of the laser
light will vary smoothly at the edges of the features.

      Disclosed anonymously.