Browse Prior Art Database

Planarization Using Metal Stud and Resist Reflow

IP.com Disclosure Number: IPCOM000111257D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Satoh, K: AUTHOR [+2]

Abstract

Disclosed is a process for making flat metal circuit lines in the manufacture of multilayer wiring board or substrates. The key point is that after the etching of a contact hole in an insulator using a resist as a mask, a metal is deposited onto the resist to form a metal stud in the contact hole and then the resist is reflowed to cover the top surface of the metal stud before the etching of the metal over the resist.

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Planarization Using Metal Stud and Resist Reflow

      Disclosed is a process for making flat metal circuit lines in
the manufacture of multilayer wiring board or substrates.  The key
point is that after the etching of a contact hole in an insulator
using a resist as a mask, a metal is deposited onto the resist to
form a metal stud in the contact hole and then the resist is reflowed
to cover the top surface of the metal stud before the etching of the
metal over the resist.

      Figs. 1-7 show the steps of the process.  After first level
metal 3 is covered with insulator 2 such as Si3N4 or SiO2, resist 1
is applied and patterned to expose a contact hole region of the
insulator 2 (Fig. 1).  The insulator 2 is etched by anisotropic
etching (Fig. 2).

      A metal for stud is deposited onto the resist 1 (Fig. 3).  The
metal over the resist is shown by 4A and the stud in the contact hole
is shown by 4B.  The contact hole of the insulator 2 is stuffed with
the metal stud 4B.

      Next, the resist 1 is reflowed to cover the top surface of the
stud 4B such that the stud 4B can be protected against subsequent
etching of the metal layer 4A (Fig. 4).  Then the metal layer 4B is
etched and removed (Fig. 5).

      The resist 1 is stripped (Fig. 6) and then a second level metal
5 is deposited (Fig. 7).