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Method of Automated Visual Inspection of Width and Height of Paste Lines on Ceramic Green Sheets

IP.com Disclosure Number: IPCOM000114483D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 4 page(s) / 99K

Publishing Venue

IBM

Related People

Chastang, JC: AUTHOR [+3]

Abstract

Disclosed is a non-contact automated inspection method for verifying the uniformity of paste lines on ceramic green sheets. Ceramic modules are made up of a number of layers, each known as a green sheet, which are stacked together and fired. On the surface of each green sheet are conducting lines which are created by depositing conducting paste. Ideally these continuous lines should be uniform in both height and width. It is important that variations from the prescribed specifications be identified.

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This is the abbreviated version, containing approximately 52% of the total text.

Method of Automated Visual Inspection of Width and Height of Paste
Lines on Ceramic Green Sheets

      Disclosed is a non-contact automated inspection method for
verifying the uniformity of paste lines on ceramic green sheets.
Ceramic modules are made up of a number of layers, each known as a
green sheet, which are stacked together and fired.  On the surface of
each green sheet are conducting lines which are created by depositing
conducting paste.  Ideally these continuous lines should be uniform
in both height and width.  It is important that variations from the
prescribed specifications be identified.

      The proposed measurement apparatus is a form of oblique imaging
which can be used to acquire the required dimensional information.
The oblique imaging system used here is the Oblique Viewing
Microscope (OVM) (1) shown in Fig. 1a.  The OVM is an instrument
which provides images from which the height of three dimensional
structures can be derived.  This is done using oblique illumination
and oblique observation where the angles of illumination and
observation are the same.  The illumination and observation axes
define a plane which is the plane of symmetry of the system (Fig.
1b).

      The images obtained by the OVM are acquired by a TV camera and
an image digitization/processing system of the kind used in the Pad
Analysis System (PAS) (2).  The dimensional information is derived
from these images with suitable algorithms.

      Fig. 2 shows conventional top and side views of a paste line
with uniform width but varying height.  Figs. 3 and 4 simulate the
appearance of the paste line at two different orientations under the
oblique viewing microscope where the illumination and observation
angles are 60 degrees.

      In Fig. 3a the paste lines are parallel to the symmetry plane
of the system.  This yields an image (Fig. 3b) identical to that
provided by a conventional microscope used in the normal top-down
mode.  A given pas...