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Radio Frequency Induction Water Plasma for both High Rate Polymer Ashing and Laser Debris Removal and Adhesion Enhancement

IP.com Disclosure Number: IPCOM000108469D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 93K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+6]

Abstract

Disclosed is a method for (1) uniform ashing of polyimide, (2) removal of polyimide laser debris, and (3) enhancement of polyimide surface adhesion using a single platform tool which consists of a radio frequency induction (RFI) (1,2) water vapor plasma source. Water vapor is introduced into a RFI plasma source, thus producing a plasma consisting of radicals and ions from the dissociated water vapor. A plasma generated at high power levels of 1,000 - 1,500 watts in this manner rapidly ashes (removes) polyimide from the surface and enhances adhesion of successive layers. The typical ash rate of 0.3 mm/min is obtained with the water vapor RFI plasma without magnetic confinement is comparable to that usually obtained with magnetic confinement.

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Radio Frequency Induction Water Plasma for both High Rate Polymer Ashing and Laser Debris Removal and Adhesion Enhancement

       Disclosed is a method for (1) uniform ashing of
polyimide, (2) removal of polyimide laser debris, and (3) enhancement
of polyimide surface adhesion using a single platform tool which
consists of a radio frequency induction (RFI) (1,2) water vapor
plasma source.  Water vapor is introduced into a RFI plasma source,
thus producing a plasma consisting of radicals and ions from the
dissociated water vapor.  A plasma generated at high power levels of
1,000 - 1,500 watts in this manner rapidly ashes (removes) polyimide
from the surface and enhances adhesion of successive layers.  The
typical ash rate of 0.3 mm/min is obtained with the water vapor RFI
plasma without magnetic confinement is comparable to that usually
obtained with magnetic confinement. In addition, the surface of the
polyimide after water ashing is ready for deposition of new layers of
material since the water ash simultaneously prepares the surface by
enhancing adhesion.

      Polyimide is a material used in the fabrication of multilayer
chip carriers and circuit boards.  The fabrication of these devices
requires both additive and subtractive steps.  The subtractive step
commonly used in defining vias in polyimide is laser ablation of the
polyimide.  Laser debris and some polyimide commonly need to be
removed after this process to ensure product quality. Typically, a
high-density O2 or N2O-Ar magnetically confined plasma is used to
clear the vias of debris.  Additive steps in the process include
deposition of metal interconnect lines and deposition of subsequent
layers of polyimide.  In these steps it is crucial to enhance the
adhesion between the existing polyimide and the new layer.
Typically, this is achieved by treatment of the polyimide surface in
a parallel plate plasma using water vapor as the working gas (3-5).
Prior to the disclosed method these two different processes required
two different plasma tools.

      The disclosed method is specifi...