Planarization of metal container structures
A conductive material is provided in an opening formed in an insulative material. The process involves first forming a conductive material over at least a portion of the opening and over at least a portion of the insulative material which is outside of the opening. Next, a metal-containing fill material is formed over at least a portion of the conductive material which is inside the opening and which is also over the insulative material outside of the opening. The metal-containing material at least partially fills the opening. At least a portion of both the metal-containing fill material and the conductive material outside of the opening is then removed. Thereafter, at least a portion of the metal-containing fill material which is inside the opening is then removed.
The present invention relates generally to the fabrication of semiconductive devices, and more particularly, to a method of forming conductive material in an opening in a semiconductive device. The invention also relates to the structures formed according to the various embodiments of the method herein set forth.
BACKGROUND OF THE INVENTIONIn the fabrication of integrated circuits, various layers, e.g. conductive layers and insulative layers, are formed. For example, during the formation of semiconductive devices, such as dynamic random access memories (DRAMs), insulating layers are used to electrically separate conductive layers such as doped polycrystalline silicon, aluminum, metal silicides, etc. It is often required that the conductive layers be interconnected through holes or openings in the insulating layers. Such openings are commonly referred to as contact holes, e.g. when the opening extends through an insulating layer to an active area, or vias, e.g. when the opening extends through an insulating layer between two conductive layers. The profile of an opening is of particular importance such that specific characteristics can be achieved when a contact hole or via is provided and then filled with one or more conductive materials.
Conductive materials are also formed in openings when providing certain storage cell capacitors for use in semiconductive devices, e.g. DRAMs. Storage capacity and size are important characteristics of a storage cell. Generally, a storage cell is formed with a dielectric constant material interposed between two conductive electrodes. One or more layers of various conductive materials may be used as the electrode material.
Container-type cell capacitor structures generally include the formation of an insulative layer over existing topography which has been formed over a substrate, and then openings are etched into the insulative layer. These openings allow access to the underlying topography, e.g. for a cell capacitor, which may include conductive regions, e.g. conductive plugs, active substrate regions, etc. Thereafter, a conductive layer to be used for forming the bottom electrode of the cell capacitor is formed within the openings, and may also be formed on the upper surface of the insulative layer as well. A layer of oxide material may then be used to fill the opening over the conductive material. Thereafter, this oxide material is removed to expose the layer of conductive material. The exposed layers of conductive material which are outside of the opening, e.g. which are over the top surface of the insulative layer, are then removed to separate neighboring conductive openings, thereby forming individual containers with exposed insulative material between them. Next, the oxide material still filling the conductive opening is removed, leaving the opening lined with a bottom electrode for use in forming the container-type cell capacitor.
Storage capacity and size are important characteristics in a storage cell. One way to retain the storage capacity of a device and decrease its size is to increase the dielectric constant of the dielectric layer of the storage cell capacitor. Therefore, preferably a high dielectric constant material is utilized in applications interposed between two electrodes. Many conductive metals such as platinum, rhodium, iridium, osmium, as well as other Group VIII metals, and other transition element metals, e.g. copper, silver and gold, and Group IIIa and IVa metals, e.g. aluminum, and their alloys are desirable electrode materials for such high dielectric constant capacitors.
However, many of the foregoing metals, e.g. Group VIII metals such as platinum or platinum alloys such as platinum-rhodium, are not easily planarized. An illustrative planarization problem is shown in
As shown in
Thus, there exists a need in the art for a new method of forming conductive material in openings in semiconductive devices. There is also a need for better structures containing conductive material formed therein.
SUMMARY OF THE INVENTIONIn accordance with the invention, there is set forth a method of providing a conductive material in an opening. The process involves first forming a conductive material in the opening and over at least a portion of the insulative material which is outside of the opening. Next, a metal-containing fill material is formed over at least a portion of the conductive material such that at least some of the metal-containing material is located in the opening. At least a portion of the conductive material outside of the opening is then removed. Thereafter, at least a portion of the metal-containing fill material which is inside the opening is then removed.
The invention further provides a method of forming a bottom electrode of a capacitor. A second conductive material is provided within an opening in contact the first conductive material. The second conductive material is also provided over at least a portion of an insulative material which is outside of the opening. Next, a metal-containing fill material is provided over at least a portion of the conductive material which is inside the opening and which is over the insulative layer as well. At least a portion of the metal-containing fill material which is inside the opening is next removed and the second conductive material thereby forms the bottom electrode of a capacitor.
Also included is a method of providing a conductive material in an opening which has been provided in an insulative material over a substrate, wherein the opening contacts a surface portion of the substrate. First, a conductive material is deposited over at least a portion of the inside of the opening and over at least a portion of the surface of the insulative material which is outside the opening. Next, a tungsten-containing fill material is deposited over at least a portion of the conductive material which is over the surface portion of the substrate and which is over the insulative material outside of the opening. At that point, the tungsten material at least partially fills the opening. At least a portion of the tungsten-containing fill material and the conductive material which is over the insulative material outside the opening is then removed. The removal is effected by planarization. Next, at least a portion of the tungsten-containing fill material is removed from the opening.
According to another aspect of the invention, a structure comprises a substrate with an insulative material over the substrate. There is also a conductive material formed over at least a portion of the surface of the opening and over at least a portion of the insulative material which is outside the opening. A tungsten-containing fill material is formed over at least a portion of the conductive material which is inside the opening and which is over the insulative material outside the opening, such that the tungsten-containing fill material at least partially fills the opening.
Another structure of the invention also contains a substrate and an insulative material over the substrate. A conductive material is formed over substantially all of the inside surface of the opening. A tungsten-containing fill material is formed over the conductive material and substantially fills the opening. The conductive material and the tungsten-containing material are substantially co-planar at the top of the opening.
A further method of the invention is useful in forming a bottom electrode of a capacitor and a bit line conductive plug in a semiconductive device. A first opening is provided through the surface of an insulative material provided over a substrate in the device, such that at least a portion of the opening contacts a first conductive material. A second conductive material is then provided over at least a portion of the surface of the opening which is in contact with the first conductive material, as well as over at least a portion of the surface of the insulative material which is outside the opening. A protective layer is next provided over the second conductive material. A second opening is then provided through the protective layer and through the second conductive material which is over the insulative material, as well as through the insulative material. At least a portion of the second opening contacts a third conductive material. The protective layer is then removed. A metal-containing fill material is next provided over the second conductive material which is inside the first opening and which is over the insulative material outside of the opening.
The metal-containing fill material is further provided over the second opening such that the metal-containing fill material at least partially fills both the first and second openings. A bit line conductive plug is thereby formed in the second opening. Next, at least a portion of the metal-containing fill material and the conductive material which is over the insulative material outside of both openings is removed. Thereafter, at least a portion of the metal-containing fill material from the first opening is removed so as to form the bottom electrode of the capacitor.
The invention also provides a method of planarizing a conductive material formed over an opening without substantially deforming the material. The conductive material is contacted with a metal-containing fill material such that the fill material is over the conductive material and at least partially fills the opening. The conductive material and the metal-containing fill material are then planarized such that a top portion of the conductive material and the fill material are substantially co-planar with a top portion of the opening.
Additional advantages and features of the present invention will become more readily apparent from the following detailed description and drawings which illustrate various exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention in its broadest embodiment is directed to a method of providing a conductive material in an opening in a semiconductive device, and to the structures formed therefrom.
Reference herein shall be made to the terms “substrate” and “wafer”, which are to be understood as including silicon, a silicon-on-insulator (SOI) or silicon-on-sapphire (SOS) structures, doped and undoped semiconductives, epitaxial layers of silicon supported by a base semiconductive foundation, and other semiconductive structures. In addition, when reference is made to a “substrate” or “wafer” in the following description, previous process steps may have been utilized to form arrays, regions or junctions in or over the base semiconductive structure or foundation. In addition, the semiconductive material need not be silicon-based, but could be based on silicon-germanium, germanium, indium phosphide, or gallium arsenide. The term “substrate” as used herein may also refer to any type of generic base or foundation structure.
Referring again to the drawings,
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The conductive material 212 may be formed in the opening 216 using any suitable method, such as sputtering, chemical vapor deposition (CVD) or low pressure chemical vapor deposition (LPCVD), physical vapor deposition (PVD), electroplating and electroless plating. Preferably, the conductive material 222 is formed to a thickness within the range of a few Angstroms to several hundred Angstroms, which can vary according to the needs of the skilled artisan.
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Preferably, the fill material 224 extends into at least a portion of the opening 216 as shown in
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The first conductive plug 514 may be formed of a suitably conductive material, such as polysilicon for example. Second and third conductive plugs 516, 518 have also been formed in openings provided in layer 512 to provide electrical communication between the source/drain regions 510 and a storage cell capacitor which may formed thereover. The second and third conductive plugs are also formed of suitably conductive material which may be the same or different, but is preferably polysilicon. One or more barrier layers 520, 522 have been formed over the second and third conductive plugs 516, 518. As set forth above, the barrier layer(s) may be formed from such compounds as titanium nitride, tungsten nitride, titanium silicide, or any other metal nitride or metal silicide layer. Thereafter, a second insulative layer 525 is formed with openings 502, 504 defined therein according to methods known in the art. Openings 502, 504 are preferably contact openings which are formed using available etching, e.g. wet or dry etching, techniques.
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Due at least in part to their improved electrical characteristics, the structures herein described have wide applicability in the semiconductor industry. A typical processor system which includes integrated circuits that utilize one or more of the structures formed in accordance with the present invention is illustrated generally at 600 in
The foregoing description is illustrative of exemplary embodiments which achieve the objects, features and advantages of the present invention. It should be apparent that many changes, modifications, substitutions may be made to the described embodiments without departing from the spirit or scope of the invention. The invention is not to be considered as limited by the foregoing description or embodiments, but is only limited by the scope of the appended claims.
Claims
1.-95. (canceled)
96. A method of stabilizing a conductive material within an opening, comprising:
- forming a conductive material in an opening and over at least a portion of an insulative material outside of said opening;
- forming a stabilizing metal-containing fill material over at least a portion of said conductive material such that at least some of said stabilizing metal-containing fill material is located in said opening; and
- removing substantially all of said stabilizing metal-containing fill material from said opening while maintaining said conductive material substantially undeformed.
97. The method of claim 96, wherein said stabilizing metal-containing fill material is a tungsten-containing fill material.
98. The method of claim 96, wherein said stabilizing metal-containing fill material is harder than said conductive material.
99. The method of claim 96, wherein said removing step is performed by chemical mechanical planarization.
100. The method of claim 96, wherein said conductive material has a top edge portion once formed over said insulative material, and said forming of said stabilizing metal-containing fill material is performed so as to substantially cover said top edge portion.
101. The method of claim 96, wherein after said removal of said stabilizing metal-containing fill material, said conductive material is substantially co-planar with a top surface portion of said insulative material.
102. A method of stabilizing a conductive material while forming a bottom electrode of a capacitor, comprising:
- providing a conductive material over an insulative material within an opening and outside of said opening;
- providing a stabilizing metal-containing fill material over at least a portion of said conductive material which is inside said opening and which is over said insulative material;
- removing substantially all of said stabilizing metal-containing fill material from inside said opening while maintaining said conductive material substantially undeformed; and
- forming a capacitor having said conductive material as its bottom electrode.
103. The method of claim 102, wherein said stabilizing metal-containing fill material is tungsten or tungsten nitride and is provided to be substantially co-extensive with said conductive material.
104. The method of claim 102, wherein said stabilizing metal-containing fill material is harder than said conductive material.
105. The method of claim 102, wherein said removing step is performed by chemical mechanical planarization.
106. The method of claim 102, wherein said conductive material is a bottom electrode of a container capacitor.
107. The method of claim 102, wherein said stabilizing metal-containing fill material is titanium nitride.
108. The method of claim 102, wherein said conductive material is provided by chemical vapor deposition or low pressure chemical vapor deposition.
109. A method of providing stabilizing a conductive material in an opening provided in an insulative material over a substrate, comprising:
- forming an opening in an insulative material;
- depositing a conductive material in at least a part of an interior of said opening and over at least a portion of the insulative material outside of said opening;
- depositing a stabilizing tungsten-containing fill material over at least a portion of said conductive material which is in said interior of said opening and which is over said insulative material outside of said opening, wherein said stabilizing tungsten-containing fill material at least partially fills said opening;
- removing at least a portion of said stabilizing tungsten-containing fill material and said conductive material which is over said insulative material outside of said opening; and
- removing substantially all of said stabilizing tungsten-containing fill material from said opening while maintaining said conductive material substantially undeformed.
110. The method of claim 109, wherein said stabilizing metal-containing fill material is harder than said conductive material.
111. The method of claim 109, wherein said removing steps are performed by chemical mechanical planarization.
112. The method of claim 111, wherein said planarization is performed so that a top surface of said conductive material is substantially co-planar with a top surface of said insulative material.
113. The method of claim 109, wherein said conductive material has a top edge portion once formed over said insulative material, and said depositing of said stabilizing metal-containing fill material is performed so as to substantially cover said top edge portion.
114. The method of claim 109, further comprising forming a capacitor wherein said conductive material becomes an electrode of said capacitor.
115. The method of claim 109, wherein said stabilizing tungsten-containing fill material is formed so as to substantially fill said opening.
Type: Application
Filed: Mar 29, 2006
Publication Date: Aug 3, 2006
Inventor: John Drynan (Boise, ID)
Application Number: 11/391,316
International Classification: H01L 29/94 (20060101); H01L 21/8242 (20060101);