Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-05-30
2004-05-25
Foelak, Morton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S077000
Reexamination Certificate
active
06740685
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to semiconductor devices, and in particular, to semiconductor devices having an organic low dielectric constant material and processes for the manufacture thereof.
BACKGROUND OF THE INVENTION
In an effort to increase the performance and speed of semiconductor devices, semiconductor device manufacturers have sought to reduce the linewidth and spacing of interconnects while minimizing the transmission losses and reducing the capacitative coupling of the interconnects. One way to diminish power consumption and reduce capacitance is by decreasing the dielectric constant (also referred to as “k”) of the insulating material, or dielectric, that separates the interconnects. Insulator materials having low dielectric constants are especially desirable, because they typically allow faster signal propagation, reduce capacitance and cross talk between conductor lines, and lower voltages required to drive integrated circuits.
Since air has a dielectric constant of 1.0, a major goal is to reduce the dielectric constant of insulator materials down to a theoretical limit of 1.0, and several methods are known in the art for reducing the dielectric constant of insulating materials. These techniques include adding elements such as fluorine to the composition to reduce the dielectric constant of the bulk material. Other methods to reduce k include use of alternative dielectric material matrices. Another approach is to introduce pores into the matrix.
Therefore, as interconnect linewidths decrease, concomitant decreases in the dielectric constant of the insulating material are required to achieve the improved performance and speed desired of future semiconductor devices. For example, devices having interconnect linewidths of 0.13 or 0.10 micron and below seek an insulating material having a dielectric constant (k)<3.
Currently silicon dioxide (SiO
2
) and modified versions of SiO
2
, such as fluorinated silicon dioxide or fluorinated silicon glass (hereinafter FSG) are used. These oxides, which have a dielectric constant ranging from about 3.5-4.0, are commonly used as the dielectric in semiconductor devices. While SiO
2
and FSG have the mechanical and thermal stability needed to withstand the thermal cycling and processing steps of semiconductor device manufacturing, materials having a lower dielectric constant are desired in the industry.
Methods used to deposit dielectric materials may be divided into two categories: spin-on deposition (hereinafter SOD) and chemical vapor deposition (hereinafter CVD). Several efforts to develop lower dielectric constant materials include altering the chemical composition (organic, inorganic, blend of organic/inorganic) or changing the dielectric matrix (porous, non-porous). Table I summarizes the development of several materials having dielectric constants ranging from 2.0 to 3.5. (PE=plasma enhanced; HDP=high-density plasma) However, the dielectric materials and matrices disclosed in the publications shown in Table 1 fail to exhibit many of the combined physical and chemical properties desirable and even necessary for effective dielectric materials, such as higher mechanical stability, high thermal stability, high glass transition temperature, high modulus or hardness, while at the same time still being able to be solvated, spun, or deposited on to a substrate, wafer, or other surface. Therefore, it may be useful to investigate other compounds and materials that may be used as dielectric materials and layers, even though these compounds or materials may not be currently contemplated as dielectric materials in their present form.
TABLE 1
DEPOSITION
DIELECTRIC
MATERIAL
METHOD
CONSTANT (k)
REFERENCE
Fluorinated silicon oxide
PE-CVD;
3.3-3.5
U.S. Pat. No. 6,278,174
(SiOF)
HDP-CVD
Hydrogen
SOD
2.0-2.5
U.S. Pat. Nos. 4,756,977; 5,370,903; and
Silsesquioxane (HSQ)
5,486,564; International Patent Publication
WO 00/40637; E.S. Moyer et al.,
“Ultra Low k Silsesquioxane Based Resins”,
Concepts and Needs for Low Dielectric
Constant <0.15 &mgr;m Interconnect Materials:
Now and the Next Millennium, Sponsored by
the American Chemical Society, pages 128-
146 (Nov. 14-17, 1999)
Methyl Silsesquioxane
SOD
2.4-2.7
U.S. Pat. No. 6,143,855
(MSQ)
Polyorganosilicon
SOD
2.5-2.6
U.S. Pat. No. 6,225,238
Fluorinated Amorphous
HDP—CVD
2.3
U.S. Pat. No. 5,900,290
Carbon (a-C:F)
Benzocyclobutene
SOD
2.4-2.7
U.S. Pat. No. 5,225,586
(BCB)
Polyarylene Ether (PAE)
SOD
2.4
U.S. Pat. Nos. 5,986,045; 5,874,516; and
5,658,994
Parylene (N and F)
CVD
2.4
U.S. Pat. No. 5,268,202
Polyphenylenes
SOD
2.6
U.S. Pat. Nos. 5,965,679 and 6,288,188B1;
and Waeterloos et al., “Integration Feasibility
of Porous SiLK Semiconductor Dielectric”,
Proc. Of the 2001 International Interconnect
Tech. Conf., pp. 253-254 (2001).
Thermosettable
SOD
2.3
International Patent Publication WO
benzocyclobutenes,
00/31183
polyarylenes,
thermosettable
perfluoroethylene
monomer
Poly(phenylquinoxaline),
SOD
2.3-3.0
U.S. Pat. Nos. 5,776,990; 5,895,263;
organic polysilica
6,107,357; and 6,342,454; and U.S. patent
Publication 2001/0040294
Organic polysilica
SOD
Not reported
U.S. Pat. No. 6,271,273
Organic and inorganic
SOD
2.0-2.5
U.S. Pat. No. 6,156,812
Materials
Organic and inorganic
SOD
2.0-2.3
U.S. Pat. No. 6,171,687
Materials
Organic materials
SOD
Not reported
U.S. Pat. No. 6,172,128
Organic
SOD
2.12
U.S. Pat. No. 6,214,746
Organosilsesquioxane
CVD, SOD
<3.9
WO 01/29052
Fluorosilsesquioxane
CVD, SOD
<3.9
WO 01/29141
Unfortunately, numerous organic SOD systems under development with a dielectric constant between 2.0 and 3.5 suffer from certain drawbacks in terms of mechanical and thermal properties as described above; therefore a need exists in the industry to develop improved processing and performance for dielectric films in this dielectric constant range. In addition, industry demands materials having demonstrated low dielectric constant extendibility, i.e. capable of being reduced to an even lower dielectric constant, e.g., from 2.7 to 2.5 to 2.2 to 2.0 and below.
Reichert and Mathias describe compounds and monomers that comprise adamantane molecules, which are in the class of cage-based molecules and are taught to be useful as diamond substitutes. (Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1993, Vol. 34 (1), pp. 495-6; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1992, Vol. 33 (2), pp. 144-5; Chem. Mater., 1993, Vol. 5 (1), pp. 4-5; Macromolecules, 1994, Vol. 27 (24), pp. 7030-7034; Macromolecules, 1994, Vol. 27 (24), pp. 7015-7023; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1995, Vol. 36 (1), pp. 741-742; 205
th
ACS National Meeting, Conference Program, 1993, pp. 312; Macromolecules, 1994, Vol. 27 (24), pp. 7024-9; Macromolecules, 1992, Vol. 25 (9), pp. 2294-306; Macromolecules, 1991, Vol. 24 (18), pp. 5232-3; Veronica R. Reichert, PhD Dissertation, 1994, Vol. 55-06B; ACS Symp. Ser.: Step-Growth Polymers for High-Performance Materials, 1996, Vol. 624, pp. 197-207; Macromolecules, 2000, Vol. 33 (10), pp. 3855-3859; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1999, Vol. 40 (2), pp. 620-621; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1999, Vol. 40 (2), pp. 577-78; Macromolecules, 1997, Vol. 30 (19), pp. 5970-5975; J. Polym. Sci, Part A: Polymer Chemistry, 1997, Vol. 35 (9), pp. 1743-1751; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1996, Vol. 37 (2), pp. 243-244; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1996, Vol. 37 (1), pp. 551-552; J. Polym. Sci., Part A: Polymer Chemistry, 1996, Vol. 34 (3), pp. 397-402; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1995, Vol. 36 (2), pp. 140-141; Polym, Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 1992, Vol. 33 (2), pp. 146-147; J. Appl. Polym. Sci., 1998, Vol. 68 (3), pp. 475-482). The adamantane-based compounds and monomers described by Reichert and Mathias are preferably used to form polymers with adamantane molecules at the core of a thermoset. The compounds disclosed by Reichert and Mathias in their studies, however, comprise only
Apen Paul G.
Lau Kreisler S.
Li Bo
Sullivan Edward J.
Bingham McCutchen
Foelak Morton
Honeywell International , Inc.
Thompson Sandra P.
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