Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
2000-12-01
2003-09-30
Smith, Matthew (Department: 2825)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S303000, C257S304000, C257S306000, C257S308000, C257S309000, C257S311000
Reexamination Certificate
active
06627938
ABSTRACT:
TECHNICAL FIELD
The invention pertains to capacitor constructions and methods of forming capacitors. In a particular aspect, the invention pertains to crown capacitor constructions.
BACKGROUND OF THE INVENTION
A method of forming a prior art crown capacitor construction is described with reference to
FIGS. 1 and 2
. Referring to
FIG. 1
, a semiconductive material wafer fragment
10
comprises a substrate
12
which supports an electrical node
14
. Substrate
12
can comprise, for example, lightly doped monocrystalline silicon. Electrical node
14
can comprise, for example, a conductively-doped diffusion region provided within a monocrystalline silicon substrate
12
.
To aid in interpretation of the claims that follow, the terms “semiconductive substrate” and “semiconductor substrate” are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above.
An insulative layer
16
is formed over substrate
12
. Insulative layer
16
can comprise, for example, silicon dioxide, silicon nitride, borophosphosilicate glass (BPSG), or phosphosilicate glass (PSG). Layer
16
has an opening
18
extending therethrough to electrical node
14
. A conductive plug
20
is provided within opening
18
. Conductive plug
20
can comprise, for example, a metal, or conductively doped polysilicon.
A container-shaped storage node
22
is provided over insulative layer
16
, and over conductive plug
18
. Storage node
22
is in electrical connection with electrical node
14
through conductive plug
18
. Container-shaped storage node
22
can also be referred to as a crown-shaped storage node. Storage node
22
comprises upwardly extending members
21
, and a horizontally extending member
23
.
Referring to
FIG. 2
, a dielectric material
24
is provided over storage node
22
, and a second capacitor electrode layer
26
is provided over dielectric material
24
. Dielectric material
24
can comprise, for example, a combination of silicon dioxide and silicon nitride. Alternatively, dielectric material
24
can comprise tantalum pentoxide. Second capacitor electrode
26
can comprise, for example, a metal, conductively doped polysilicon, or a metal-comprising compound, such as, for example, titanium nitride.
Storage node
22
, dielectric material
24
, and second capacitor electrode
26
, together define a crown capacitor.
A problem with the processing described above with reference to
FIGS. 1 and 2
is that the upwardly extending members
21
of storage node
22
can be easily broken during subsequent processing. It would therefore be desirable to develop alternative methods of forming crown capacitors.
SUMMARY OF THE INVENTION
In one aspect, the invention encompasses a method of forming a capacitor. A mass is formed over an electrical node. An opening is formed within the mass. The opening has a lower portion proximate the node and an upper portion above the lower portion. The lower portion is wider than the upper portion. A first conductive layer is formed within the opening and along a periphery of the opening. After the first conductive layer is formed, a portion of the mass is removed from beside the upper portion of the opening while another portion of the mass is left beside the lower portion of the opening. A dielectric material is formed over the first conductive layer, and a second conductive layer is formed over the dielectric material. The second conductive layer is separated from the first conductive layer by the dielectric material.
In another aspect, the invention encompasses a capacitor construction. Such construction includes an insulative mass over an electrical node, and an opening extending through the mass to the electrical node. The construction further includes a storage node layer within the opening. The storage node layer extends around a periphery of the opening and protrudes above the insulative mass. The storage node layer defines a container shape having a void extending therein. The void has a lower portion within the opening and an upper portion above the opening. The upper portion of the void is narrower than the lower portion. Additionally, the construction includes a dielectric material within the void and partially filling the void, and a second capacitor electrode within the void and separated from the first conductive layer by the dielectric material.
REFERENCES:
patent: 5391511 (1995-02-01), Doan et al.
patent: 5436188 (1995-07-01), Chen
patent: 5545585 (1996-08-01), Wang et al.
patent: 5597756 (1997-01-01), Fazan et al.
patent: 5604147 (1997-02-01), Fischer et al.
patent: 5821141 (1998-10-01), Huang
patent: 6043119 (2000-03-01), Wu et al.
patent: 6046093 (2000-04-01), DeBoer et al.
patent: 6080620 (2000-06-01), Jeng
patent: 6107139 (2000-08-01), Tu et al.
patent: 6335552 (2002-01-01), Mitani
Parekh, K., U.S. patent application Ser. No. 08/798,251 filed on Feb. 11, 1997.
Kwok Siang Ping
Richardson William F.
Malsawma Lex H.
Smith Matthew
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