ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 10, pp. 1681!1685. + Pleiades Publishing, Inc., 2006.
Original Russian Text + S.F. Sen’ko, Yu.P. Snitovskii, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 10, pp. 1701!1705.
AND POLYMERIC MATERIALS
Adhesion of Polyimide Films to Microelectonic
S. F. Sen’ko and Yu. P. Snitovskii
Physicotechnical Institute, National Academy of Sciences of Belarus, State Scientific Establishment, Minsk, Belarus
Belarus State University of Informatics and Radioelectronics, Educational Establishment, Minsk, Belarus
Received April 13, 2006; in final form, June 5, 2006
Abstract-Reactions between polypyromellitamido acid and component materials of microelectronic articles
were examined by thermogravimetric analysis. Modes of modification of the surfaces of semiconductor struc-
tures to be used in formation of a system of interconnections with polyimide as interlayer insulator to obtain
a high adhesion between the layers via their chemical reactions.
The miniaturization of the active elements of mi-
croelectronic articles and the ensuing increase in
the degree of integration are responsible for the fact
that a steadily growing area of the crystal (chip) is
occupied by electric interconnections. An increase in
the length of interconnections, with a simultaneous
decrease in their cross section, leads to a pronounced
rise in both the resistance and capacitance. This strong-
ly limits the speed of response of devices.
A possible solution to this problem is to create
multilevel interconnections, which, in, turn, give rise
to many other problems. The most significant among
them are breaks of the interconnecting paths and dis-
turbance of the continuity of the insulator films at
steps of the topological profile.
This problem can be tackled with by using films of
organic insulators and, in particular, polyimides [13 4]
ensuring the required planarity and continuity of the
coatings. However, polyimides are chemically inert
compounds and do not enter into chemical reactions
with components of microelectronic articles (Si, SiO
, etc.), used for fabrication of interconnec-
tion systems. This results in an unsatisfactory ad-
hesion of the films of the multilayer system and
gives no way of obtaining the required parameters
of the structures being manufactured.
Lee et al.  suggested to raise increasing the ad-
hesion by forming an independent intermediate layer
based on g-aminopropyltriethoxysilane. Its hydrolysis
yields silicon dioxide with attached amino groups,
which react with the functional groups of polyamido
acid to form a chemical bond between the film and
the substrate. However, the method of preparation of
such a film does not satisfy the requirements of mi-
croelectronics as regards the purity, defectiveness,
carbon content, and other characteristics. Yih et al.
 introduced various additives directly into the poly-
imide formulation, but this markedly affected the in-
sulation quality. It should be noted that all the above-
described options only partially, rather than cardinal-
ly, solve the problem.
Babaevskii et al.  found that physicochemical
modification of thin polyimide films and coatings by
plasmochemical treatment and treatment in hexameth-
yldisilasane vapor affects the nature of the bonds, sur-
face and bulk properties, and nature of inter-phase
interaction across the whole width of the films. We
suggested that the grains in the films should be pre-
dominantly oriented in the (110) plane to improve
the adhesion of aluminum films to other layers .
Today, the mostly used organic interlevel insula-
tors are polypyromellitimide (PI) films. A character-
istic feature of their preparation procedure is that
a film of polypyromellitamido acid (PAA) is formed
on the semiconductor substrate and is converted to
polyimide by heat treatment. In contrast to PI, the
PAA macromolecules contain chemically active func-
tional groups 3COOH and 3NH3, which can, under
certain conditions, react with the materials of the con-
tacting layers and provide adhesion between them.
Diverse physicochemical processes are used to
form the multilevel interconnection system for micro-