Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2001-03-08
2003-02-11
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S125000, C528S126000, C528S128000, C528S170000, C528S172000, C528S173000, C528S174000, C528S176000, C528S179000, C528S183000, C528S188000, C528S220000, C528S229000, C528S272000, C528S274000, C528S327000, C528S350000, C528S360000, C528S373000, C528S377000, C526S256000, C526S258000, C526S262000, C526S285000, C526S286000, C526S288000, C525S282000, C525S422000, C568S018000
Reexamination Certificate
active
06518392
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to dielectric materials and their use in integrated circuits. More particularly, the invention pertains to novel dielectric polymer compositions, oligomeric precursors and methods for preparing the compositions, and integrated circuit devices fabricated therewith.
BACKGROUND
Polyimides are known in the art for use in the manufacture of integrated circuits including chips (e.g., chip back end of line, or “BEOL”), thin film packages, and printed circuit boards. Polyimides are useful in forming dielectric interlayers, passivation layers, alpha particle barriers, and stress buffers. Polyimides are particularly useful as an interlayer dielectric material to insulate the conductor wiring interconnecting the chips on a multichip module. This is known as “thin film” wiring. Multichip modules represent an intermediate level of packaging between the chips and the circuit board, and are generally known in the art. Multichip modules are made up of multiple layers of power, signal, and ground planes which deliver power to the chips and distribute the input/output signals between chips on the module or to and from the circuit board.
There is a continuing desire in the microelectronics industry to increase the circuit density in multilevel integrated circuit devices, e.g., memory and logic chips, thereby increasing performance and reducing cost. In order to accomplish these goals, those in the field are striving to reduce the minimum feature sizes, e.g., metal lines and vias, and to decrease the dielectric constant of the interposed dielectric material to enable closer spacing of circuit lines without a concomitant increase in crosstalk and capacitive coupling. Polyimides usually have dielectric constants of about 3.0-3.8 and mechanical and thermal properties sufficient to withstand present processing operations including the thermal cycling associated with semiconductor manufacturing. However, there is a need in the art for a dielectric material that would be suitable for use in integrated circuit devices, wherein the material exhibits a lower dielectric constant (e.g., <3.0) than typically exhibited by polyimides and has improved mechanical and thermal properties.
The invention is addressed to the aforementioned need in the art, and, in one embodiment, provides a novel dielectric composition that represents a significant improvement over prior dielectric materials used in integrated circuit devices. The composition is formed by imidizing and curing an oligomeric precursor compound comprised of a central polyamic acid or polyamic acid ester segment terminated at each end with an aromatic species substituted with two or more aryl-substituted ethynyl moieties. These oligomeric compounds, dielectric compositions formed therefrom, and associated methods of manufacture and use will be discussed in detail herein.
Compounds that are end-capped with two or more diaryl-substituted acetylene moieties at each of two termini are known and described, for example, in PCT Publication No. WO 97/10193. The reference does not, however, describe end-capped oligomeric segments comprised of polyamic acid, a polyamic acid ester, or the like.
U.S. Pat. No. 5,138,028 to Paul et al. is also of interest insofar as polyimides end-capped with diaryl-substituted acetylene are disclosed. Only one diaryl-substituted acetylene moiety is present at each terminus, resulting in higher curing temperature and less efficient cross linking than possible with the oligomeric precursor compounds of the invention.
John et al. (1994), “Synthesis of Polyphenylenes and Polynaphthalenes by Thermolysis of Enediynes and Dialkynylbenzenes,”
J. Am. Chem. Soc.
116:5011-5012, is of background interest insofar as the publication describes thermal polymerization of substituted enediynes. U.S. Pat. No. 5,773,197 to Carter et al. is also a background reference that is of interest with respect to the present invention, in that the patent describes the manufacture and use of integrated circuit devices in which a dielectric material contained therein is synthesized on a substrate.
No art of which applicants are aware, however, describes or suggests the dielectric compositions as now provided herein, or the oligomeric precursor compounds that are imidized and crosslinked to form the compositions. In contrast to the dielectric materials of the prior art, the present compositions provide the following advantages: (1) the precursor to the present dielectric compositions has a lower solution viscosity than other polyimide precursors, allowing for superior planarization and gap filling; (2) the present dielectric compositions have a low dielectric constant, less than 3.0, which is lower than that of currently used dielectric materials; and (3) films of the novel dielectric compositions have superior mechanical properties relative to current dielectric materials used in the manufacture of integrated circuit devices and packages. The compositions also find utility in laminates, composites and the like.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the invention to address the above-mentioned need in the art by providing novel dielectric materials that are useful, inter alia, in integrated circuit devices.
It is another object of the invention to provide oligomeric precursor compounds useful for preparing the novel dielectric compositions.
It is still another object of the invention to provide such oligomeric precursor compounds comprised of a central oligomeric segment end-capped at each of two termini with an aryl-substituted acetylene moiety such as an ortho-bis(arylethynyl)aryl group.
It is yet another object of the invention to provide such oligomeric precursor compounds wherein the central oligomeric segment is a polyamic acid, a polyamic acid ester, a polybenzoxazole, or a polybenzothiazole.
It is a further object of the invention to provide methods for synthesizing the oligomeric precursor compounds and methods for preparing the novel dielectric compositions therefrom.
It is still a further object of the invention to provide end-capping reagents comprised of aryl-substituted acetylene compounds, suitable for preparing the aforementioned oligomeric precursor compounds.
It is an additional object of the invention to provide an integrated circuit device in which metallic circuit lines on a substrate are electrically insulated from each other by a dielectric material that comprises a dielectric composition of the invention.
Still a further object of the invention is to provide an integrated circuit packaging device (multichip module) that incorporates a dielectric material comprising a dielectric composition of the invention.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.
In a first embodiment of the invention, then, an oligomeric precursor compound is provided that can be imidized and crosslinked to prepare a dielectric material, the oligomeric precursor compound having the structural formula (I)
wherein:
n is an integer of 2 or more;
q is 0 or 1;
R is an oligomeric unit comprised of polyamic acid, a polyamic acid ester, a polybenzoxazole or a polybenzothiazole;
R
1
is an aromatic group optionally substituted at one or more available carbon atoms with an inert, nonhydrogen substituent and optionally containing one or more heteroatoms;
L is a linking group, and, as q may be 0, is optional; and
Ar is arylene optionally substituted at one or more available carbon atoms with an inert, nonhydrogen substituent and optionally containing one or more heteroatoms.
In a related embodiment, the invention pertains to end-capping reagents useful in synthesizing the aforementioned oligomeric precursor compounds, wherein the reagents are comprised of aryl-substituted acetylene compounds generally having the structural formula (II)
wherein R
1
, L, q, n and Ar are as defined
Carter Kenneth R.
Hedrick James L.
Lee Victor Yee-Way
McHerron Dale C.
Miller Robert D.
Hampton-Hightower P.
International Business Machines - Corporation
Reed & Associates
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