Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1999-01-07
2001-01-23
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of silicon containing
C427S240000, C428S336000
Reexamination Certificate
active
06177199
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates generally to dielectric films formed from siloxane based resins and methods of manufacturing those films, and more specifically to low dielectric constant films formed from low organic content organohydridosiloxane compositions and methods of manufacture thereof.
2. Related Art
Semiconductor devices often have one or more arrays of patterned interconnect levels that serve to electrically couple the individual circuit elements thus forming an integrated circuit (IC). These interconnect levels are typically separated by an insulating or dielectric film. Previously, a silicon oxide film formed using chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD) techniques was the most commonly used material for such dielectric films. However, as the size of circuit elements and the spaces between such elements decreases, the relatively high dielectric constant of such silicon oxide films is problematic.
In order to provide a lower dielectric constant than that of silicon oxide, dielectric films formed from siloxane based resins are becoming widely used. One such family of films formed from siloxane based resins are the films derived from hydrogen silsesquioxane (HSQ) resins (See, U.S. Pat. No. 3,615,272, Oct. 19, 1971, Collins et al.; and U.S. Pat. No. 4,756,977, Jul. 12, 1988, Haluska et al.) However, while such films do provide lower dielectric constants than CVD or PECVD silicon oxide films and also provide other benefits such as enhanced gap filling and surface planarization, it has been found that typically the dielectric constants of such films are limited to approximately 3.0 or greater (See, U.S. Pat. No. 5,523,163, Jun. 4, 1996, Ballance et al.).
Since, as known, the dielectric constant of such insulating films is an important factor where IC's with low power consumption, cross-talk, and signal delay are required, forming an insulating film with a dielectric constant below 3.0 is desirable. As siloxane based resin materials have beneficial gap filling and planarization properties, forming such films from siloxane based resin materials is very desirable. In addition, it would be desirable to have low dielectric constant films formed from siloxane based resin materials which have a high resistance to cracking. Additionally, it would be desirable to manufacture low dielectric constant films from siloxane based resins via standard processing techniques. In this manner curing processes that require an ammonia or ammonia derivative type of atmosphere (See, U.S. Pat. No. 5,145,723, Sep. 8, 1992, Ballance et al.), an ozone atmosphere (See, U.S. Pat. No. 5,336,532, Haluska et al.), or other non-standard type of semiconductor process, are avoided.
SUMMARY
In accordance with the present invention, methods of using solutions of organohydridosiloxane resins of low organic content to manufacture low dielectric constant insulating films are provided.
The solutions from which the dielectric films in accordance with the present invention are formed, contain organohydridosiloxane resins having one of the four general formulae:
(HSiO
1.5
)
n
(RSiO
1.5
)
m
; or
Formula 1
(H
0.5-1.0
SiO
1.5-1.8
)
n
(R
0.5-1.0
SiO
1.5-1.8
)
m
; or
Formula 2
(H
0-1.0
SiO
1.5-2.0
)
n
(RSiO
1.5
)
m
; or
Formula 3
(HSiO
1.5
)
x
(RSiO
1.5
)
y
(SiO
2
)
z
Formula 4
wherein:
the sum of n and m is from about 8 to about 5000, and m is selected such that the organic substituent is present to between about 0.1 and about 40 Mole percent (Mol %); the sum of x, y and z is from about 8 to about 5000 and y is selected such that the organic substituent is present to between about 0.1 and about 40 Mol %; and R is selected from substituted and unsubstituted groups including normal and branched alkyl groups, cycloalkyl groups, aryl groups, and mixtures thereof; and
wherein the specific Mol % of organic or carbon containing substituents is a function of the ratio of the amounts of starting materials.
Embodiments of the present invention employ solutions containing organohydridosiloxane resins having a caged structure. These organohydridosiloxane resins have a polymer backbone encompassing alternate silicon and oxygen atoms. In particular, each backbone silicon atom is bonded to at least three backbone oxygen atoms. In contrast with previously known organosiloxane resins, polymers of the present invention have essentially no hydroxyl or alkoxy groups bonded to backbone silicon atoms. Rather, each silicon atom, in addition to the aforementioned backbone oxygen atoms, is bonded only to hydrogen atoms and/or R groups as defined in Formulae 1, 2, 3 and 4. By attaching only hydrogen and/or R groups directly to backbone silicon atoms in the polymer, unwanted chain lengthening and cross-linking is avoided.
Some embodiments in accordance with the present invention employ spin coating techniques for application of solutions of the organohydridosiloxane resins. Typically, such resin solutions are approximately 5% to 35% (by weight) resin in an appropriate solvent.
In certain embodiments of the present invention, dielectric films formed from organohydridosiloxane resin solutions by spin coating methods are provided. Such dielectric films advantageously have low dielectric constants, of approximately 3.0 or lower.
DETAILED DESCRIPTION
As the present invention is described with reference to various embodiments thereof, it will be understood that these embodiments are presented as examples and not limitations of this invention. Thus, various modifications or adaptations of the specific materials and methods may become apparent to those skilled in the art. All such modifications, adaptations or variations that rely upon the teachings of the present invention as illustrated by the embodiments herein, are considered to be within the spirit and scope of the present invention.
Methods of forming dielectric films from solutions containing organohydridosiloxane resins are provided according to embodiments of the present invention. The solutions contain organohydridosiloxane resins having one of the four general formulae:
(HSiO
1.5
)
n
(RSiO
1.5
)
m
; or
Formula 1
(H
0.5-1.0
SiO
1.5-1.8
)
n
(R
0.5-1.0
SiO
1.5-1.8
)
m
; or
Formula 2
(H
0-1.0
SiO
1.5-2.0
)
n
(RSiO
1.5
)
m
; or
Formula 3
(HSiO
1.5
)
x
(RSiO
1.5
)
y
(SiO
2
)
z
Formula 4
wherein:
the sum of n and m is from about 8 to about 5000 and m is selected such that the organic substituent is present to between about 0.1 and about 40 Mole percent (Mol %); the sum of x; y and z is from about 8 to about 5000 and y is selected such that the organic substituent is present to between about 0.1 and about 40 Mol %; and R is selected from substituted and unsubstituted groups including normal and branched alkyl groups, cycloalkyl groups, aryl groups, and mixtures thereof; and
wherein the specific Mol % of organic or carbon containing substituents is a function of the ratio of the amounts of starting materials. In some embodiments, particularly favorable results are obtained with the mole percent of organic substituents being in the range of between about 5 Mol % to about 25 Mol %. For substituent R a methyl group, this range corresponds to a carbon content of the organohydridosiloxane resin of between about 1% and about 6% by weight.
The organohydridosiloxane resins used in making dielectric films, according to embodiments of the present invention, can have molecular weights between about 400 and 200,000 atomic mass units. All molecular weights are reported as weight average molecular weights. Preferably the resins have molecular weights between about 1000 and 100,000 atomic mass units and most preferably between about 10,000 and 60,000 atomic mass units.
The organohydridosiloxane resins used in making the dielectric films are further described in U.S. patent application Ser. No. 09/044,831, now pending entitled “ORGANOHYDRIDOSILOXANE RESINS WITH LOW ORGANIC CONTENT”, which is commonly assigned with the present application and is incorporated herein by reference.
Methods of the present invention typically employ spin coating tech
Figge Lisa K.
Hacker Nigel P.
Lefferts Scott P.
Allied-Signal Inc.
Nakarani D. S.
Saxon Roberta P.
Skjerven Morrill & MacPherson LLP
LandOfFree
Dielectric films from organohydridosiloxane resins with low... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dielectric films from organohydridosiloxane resins with low..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dielectric films from organohydridosiloxane resins with low... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2481622