Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
2002-04-05
2004-05-18
Moore, Margaret G. (Department: 1712)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C427S387000, C427S515000, C525S477000
Reexamination Certificate
active
06737117
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to dielectric coatings in semiconductor devices. More particularly, it relates to dielectric coatings formed from siloxane-based resins and having relatively low dielectric constant, relatively low SiH content, and relatively high modulus.
BACKGROUND OF THE INVENTION
Semiconductor devices often have one or more arrays of patterned interconnect levels that serve to electrically couple the individual circuit elements forming an integrated circuit (IC). The interconnect levels are typically separated by an insulating or dielectric coating. Previously, a silicon oxide coating formed using chemical vapor deposition (CVD) or plasma enhanced techniques (PECVD) was the most commonly used material for such dielectric coatings.
Dielectric coatings formed from siloxane-based resins have found use because such coatings provide lower dielectric constants than CVD or PECVD silicon oxide coatings and also provide other benefits such as enhanced gap filling, surface planarization and have a high resistance to cracking. It is desirable for such siloxane-based resins to provide coatings by standard processing techniques such as spin coating.
In general, there are two types of dielectric coatings which serve as inter-layer dielectrics (ILD). The first type is a pre-metal dielectric material (PMD) formed before a metalization process is performed. The PMD serves as an insulating layer between the semiconductor component and the first metal layer. The second type of dielectric is an inter-metal dielectric (IMD), which is a dielectric layer interposed between two metallic layers for insulation.
Semiconductor processes for manufacturing integrated circuits often require forming a protective layer, or layers, to reduce contamination by mobile ions, prevent unwanted dopant diffusion between different layers, and isolate elements of an integrated circuit. Typically, such a protective layer is formed with silicon-based dielectrics, such as silicon dioxide, which may take the form of undoped silicate glass, borosilicate glass (BSG) or borophosphorous silicate glass (BPSG). If these dielectrics are disposed beneath the first metal layer of the integrated circuit, they are often referred to as pre-metal dielectrics.
Hydrosilsesquioxanes, such as FOx resins available from Dow Corning, Midland Mich., are widely used in the semiconductor industry as interlevel dielectric materials. However, in the continuing pursuit of high speed and high performance chips, hydrosilsesquioxanes that form silica layers with a higher modulus and higher crack resistance are desirable. Also desirable are the formation of silica layers having reduced SiH content and improved planarization and gap fill. These properties would enhance ease of integration.
Zhong, U.S. Pat. No. 6,143,360, teaches a method for preparing a nanoporous silicone resin involving contacting a hydridosilicon containing resin with a C
8
-C
28
1-alkene in the presence of a platinum group metal-containing hydrosilation catalyst, with subsequent thermolysis of the alkene groups from the reaction product.
Zhong, U.S. Pat. No. 6,197,913, teaches a method for preparing a nanoporous silicone resin involving contacting a hydridosilicon containing resin with an alkenyltriarylsilane in the presence of a platinum group metal-containing hydrosilation catalyst, with subsequent thermolysis of the triarylsilylalkylene groups from the reaction product.
Zhong, U.S. Pat. No. 6,232,424, teaches silicone resin compositions and methods for their preparation, wherein the resin comprises the reaction product of a tetraalkoxysilane, wherein the alkoxy groups have from 1 to about 6 carbon atoms, an organosilane comprising one C
1
-C
6
alkyl group or phenyl group and three hydrolyzable substituents, and an organotrialkoxysilane comprising one C
8
-C
24
hydrocarbon group and three C
1
-C
6
alkyl groups.
Mikoshiba et al., U.S. Pat. No. 6,022,814, discloses a polymer having a repeating unit of the structure R
1
SiO
3/2
, R
1
(R
2
)SiO
2/2
, or R
1
2
SiO
2/2
, wherein R
1
is a substituent group that can be eliminated at a temperature ranging from 250° C. to the glass transition temperature of the polymer. Examples of R
1
include 3,3,3-trifluoropropyl, &bgr;-phenethyl, t-butyl, 2-cyanoethyl, benzyl, and vinyl. Mikoshiba teaches that the polymer can be blended with a hydrosilsesquioxane resin. The dielectric constant, SiH content, and modulus of a silica film formed from the resin were not reported.
Wojtowicz, U.S. Pat. No. 5,665,809, teaches a method of fabricating an extruded silicone gel profile, wherein the silicone gel comprises a first silicone component comprising methyl, ethyl, higher alkyl, 3,3,3-trifluoropropyl, or phenyl substituents and a second silicone component comprising methyl, ethyl, higher alkyl, 3,3,3-trifluoropropyl, or phenyl substituents. Wojtowicz did not teach the formation of a silica film.
Cho, U.S. Pat. No. 5,665,849, teaches a modified hydrogen silsesquioxane (HSQ) precursor comprising HSQ and a modifying agent, such as alkyl alkoxysilane.
Hacker et al., U.S. Pat. Nos. 6,143,855 and 6,177,199, teach organohydridosiloxane polymers having organic substituents, and a process of making dielectric films therefrom.
A need remains for silica coatings which have relatively low dielectric constants as well as relatively low SiH content and relatively high modulus.
SUMMARY OF THE INVENTION
In one embodiment, the present invention relates to a resin blend, comprising:
(a) about 0.1 solids wt % to about 50 solids wt % of an organosiloxane resin comprising the formula (RSiO
3/2
)
x
(R′SiO
3/2
)
y
, wherein R is selected from the group consisting of C
4
-C
24
alkyl, C
4
-C
24
alkenyl, C
4
-C
24
alkoxy, C
8
-C
24
alkenoxy, and C
4
-C
24
substituted hydrocarbon; R′ is selected from the group consisting of —H, C
1
-C
4
unsubstituted hydrocarbon, and C
1
-C
4
substituted hydrocarbon; x is from about 5 mole % to about 75 mole %; y is from about 10 mole % to about 95 mole %; and x+y is at least about 40 mole %; and
(b) about 50 solids wt % to about 99.9 solids wt % of a resin comprising at least about 90 mole % of the formula HSiO
3/2
.
In another embodiment, the present invention relates to an organosiloxane resin comprising the formula (RSiO
3/2
)
x
(HSiO
3/2
)
y
, wherein R is selected from the group consisting of C
4
-C
24
alkyl, C
4
-C
24
alkenyl, C
4
-C
24
alkoxy, C
8
-C
24
alkenoxy, and C
4-C≧
substituted hydrocarbon; x is from about 5 mole % to about 75 mole %; y is from about 10 mole % to about 95 mole %; and x+y is at least about 40 mole %.
In a further embodiment, the present invention relates to a method of preparing a solid coating, comprising:
(i) applying a resin solution comprising (a) about 0.1 solids wt % to about 50 solids wt % of an organosiloxane resin comprising the formula (RSiO
3/2
)
x
(R′SiO
3/2
)
y
, wherein R is selected from the group consisting of C
4
-C
24
alkyl, C
4
-C
24
alkenyl, C
4
-C
24
alkoxy, C
8
-C
24
alkenoxy, and C
4
-C
24
substituted hydrocarbon; R′ is selected from the group consisting of —H, C
1
-C
4
unsubstituted hydrocarbon, and C
1
-C
4
substituted hydrocarbon; x is from about 5 mole % to about 75 mole %; y is from about 10 mole % to about 95 mole %; and x+y is at least about 40 mole %; (b) about 50 solids wt % to about 99.9 solids wt % of a resin comprising at least about 90 mole % of the formula HSiO
3/2
; and (c) a solvent, wherein the resin solution comprises from about 0.5 w/v % total solids to about 50 w/v % total solids, to a surface;
(ii) removing the solvent from the resin solution;
(iii) removing R groups from the organosiloxane resin; and
(iv) curing the resin solution, to form the solid coating.
The resin solution and methods of the present invention enhance the formation of silica coatings which have relatively low dielectric constants as well as relatively low SiH content and relatively high modulus.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment, the present invention relates to a resin blend, co
Boisvert Ronald P.
Bujalski Duane R.
Harkness Brian R.
Li Zhongtao
Su Kai
Dow Corning Corporation
Moore Margaret G.
Williams Morgan & Amerson P.C.
Zimmer Marc S
LandOfFree
Hydrosilsesquioxane resin compositions having improved thin... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydrosilsesquioxane resin compositions having improved thin..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrosilsesquioxane resin compositions having improved thin... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3197868