METHOD OF FORMING GAS DIELECTRIC WITH SUPPORT STRUCTURE
A method for forming a gas dielectric with support structure on a semiconductor device structure provides low capacitance and adequate support for a conductor of the semiconductor device structure. A conductive structure, such as via or interconnect, is formed in a wiring-layer dielectric. A support is then formed that connects to the conductive structure, the support including an area thereunder. The wiring-layer dielectric is then removed from the area to form a gas dielectric.
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1. Technical Field
The invention relates generally to semiconductor device structures and more specifically to a gas dielectric with support structure formed on a semiconductor device structure.
2. Related Art
In order to enhance chip operational speed, semiconductor devices have been continuously scaled down in size. Unfortunately, as semiconductor device size is decreased, the capacitive coupling between conductors in a circuit tends to increase since the capacitive coupling is inversely proportional to the distance between the conductors. This coupling may ultimately limit the speed of the chip or otherwise inhibit proper chip operation if steps are not taken to reduce the coupling.
The capacitance between conductors is also dependent on the insulator, or dielectric, used to separate the conductors. Traditional semiconductor fabrication commonly employs silicon dioxide as a dielectric, which has a dielectric constant of approximately 3.9. One challenge facing further development is finding materials with a lower dielectric constant that can be used between the conductors. As the dielectric constant of such materials is decreased, the speed of performance of the chip is increased. Some materials that have been used to provide a lower dielectric constant between conductors include fluorinated glass, organic materials and organic materials containing gas, such as air. Unfortunately, organic materials suffer from temperature limitations, shrinkage or swelling during manufacturing or chip operation, and poor structural integrity. Application of simple gas dielectric structures tends to create sagging of long line conductors as well as producing poor structural integrity.
Accordingly, a need has developed in the art for a method of forming a dielectric structure on a semiconductor device structure that will provide low capacitance but adequate support for the conductors.
SUMMARY OF INVENTIONThe present invention provides a method for forming a gas dielectric structure on a semiconductor device structure that will provide low capacitance and adequate support for the conductors.
Generally, a first aspect of the present invention is directed to a method of forming a gas dielectric with support structure comprising the steps of: providing a conductive structure in a wiring-layer dielectric; forming a support connected to the conductive structure, the support including an area thereunder; and removing the wiring-layer dielectric from the area to form a gas dielectric.
In addition, a second aspect of the present invention provides a semiconductor device structure comprising: a semiconductor substrate; a conductive structure; a support connected to and coplanar to a top surface of the conductive structure, the support including an area thereunder; and a gas dielectric in the area and surrounding a portion of the conductive structure.
The present invention also provides a method of forming a gas dielectric with support structure comprising the steps of: providing an underlying structure; forming a via-layer dielectric on the underlying structure; forming a wiring-layer dielectric on the via-layer dielectric; forming a conductive structure in the wiring-layer dielectric; forming a support connected to and coplanar to a top surface of the conductive structure, the support including an area thereunder; and removing the wiring-layer dielectric from the area to form a gas dielectric.
The foregoing and other features of the invention will be apparent from the following more particular description of embodiments of the invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGSEmbodiments of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and wherein:
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The present invention provides a plurality of methods for forming a gas dielectric structure on a semiconductor device structure that will provide low capacitance and adequate support for the interconnects of the semiconductor device structure.
While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims
1. A method of forming a gas dielectric with support structure comprising the steps of:
- providing a conductive structure in a wiring-layer dielectric, the conductive structure being separated from the wiring-layer dielectric by a vertical structure;
- forming a support connected to the conductive structure, the support including an area thereunder; and
- removing the wiring-layer dielectric and the vertical structure from the area to form a gas dielectric.
2. The method of claim 1, further comprising the steps of:
- providing the conductive structure as a first interconnect; and
- providing a second interconnect in spaced relation away from the first interconnect in the wiring-layer dielectric, wherein the support forms a bridge connecting the first interconnect with the second interconnect.
3. The method of claim 2, wherein the bridge is formed coplanar with a top surface of the first interconnect and the second interconnect.
4. The method of claim 2, further comprising the steps of:
- providing a via-layer dielectric layer;
- providing the wiring-layer dielectric on the via-layer dielectric; and
- removing a portion of the via-layer dielectric, wherein the gas dielectric surrounds the bottom of the first interconnect and the second interconnect.
5. The method of claim 1, wherein the support is formed coplanar with a top surface of the conductive structure.
6. The method of claim 1, wherein the support includes a dielectric material.
7. The method of claim 1, further comprising the steps of:
- providing a via-layer dielectric;
- providing the wiring-layer dielectric on the via-layer dielectric; and
- removing a portion of the wiring-layer dielectric, wherein the gas dielectric surrounds a portion of a bottom of the conductive structure.
8. The method of claim 1, wherein forming the support further comprises the steps of:
- forming a stopping layer on the wiring-layer dielectric;
- forming a sacrificial layer on the stopping layer;
- selectively removing a portion of the sacrificial layer, the stopping layer, and the wiring layer dielectric for placement of the conductive structure;
- forming the vertical structure as a vertical sacrificial spacer in the portion selectively removed to surround a portion of the conductive structure;
- forming the conductive structure between the vertical sacrificial spacer;
- partially removing the conductive structure substantially coplanar to a top surface of the sacrificial layer;
- removing the sacrificial layer and a top portion of the vertical sacrificial spacer; and
- forming a support with the stopping layer and a material on the vertical sacrificial spacer, wherein the material is formed coplanar to a top surface of the stopping layer and connects to the conductive structure.
9-15. (canceled).
16. A method of forming a gas dielectric with support structure comprising the steps of:
- providing an underlying structure;
- forming a via-layer dielectric on the underlying structure;
- forming a wiring-layer dielectric on the via-layer dielectric;
- forming a conductive structure in the wiring-layer dielectric, the conductive structure being separated from the wiring-layer dielectric by a vertical structure;
- forming a support connected to and coplanar to a top surface of the conductive structure, the support including an area thereunder; and
- removing the wiring-layer dielectric and the vertical structure from the area to form a gas dielectric.
17. The method of claim 16, further comprising the steps of:
- providing the conductive structure as a first interconnect; and
- providing a second interconnect in spaced relation away from the first interconnect in the wiring-layer dielectric, wherein the support forms a bridge connecting the first interconnect with the second interconnect.
18. The method of claim 16, wherein the conductive structure includes a wire.
19. The method of claim 16, wherein the support includes a dielectric material.
20. The method of claim 16, further comprising the step of removing a portion of the via-layer dielectric, wherein the gas dielectric surrounds a portion of a bottom of the conductive structure.
21. The method of claim, 1, wherein the conductive structure includes a wire.
22. The method of claim 16, further comprising the step of removing a portion of the wiring-layer dielectric, wherein the gas dielectric surrounds a portion of a bottom of the conductive structure.
23. The method of claim 17, wherein the bridge is formed coplanar with a top surface of the first interconnect and the second interconnect.
24. The method of claim 17, further comprising the step of removing a portion of the via-layer dielectric, wherein the gas dielectric surrounds the bottom of the first interconnect and the second interconnect.
25. The method of claim 16, wherein forming the support further comprises the steps of:
- forming a stopping layer on the wiring-layer dielectric;
- forming a sacrificial layer on the stopping layer; and
- selectively removing a portion of the sacrificial layer, the stopping layer, and the wiring layer dielectric for placement of the conductive structure.
26. The method of claim 25, further comprising the steps of:
- forming the vertical structure as a vertical sacrificial spacer in the portion selectively removed to surround a portion of the conductive structure;
- forming the conductive structure between the vertical sacrificial spacer;
- partially removing the conductive structure substantially coplanar to a top surface of the sacrificial layer;
- removing the sacrificial layer and a top portion of the vertical sacrificial spacer; and
- forming a support with the stopping layer and a material on the vertical sacrificial spacer, wherein the material is formed coplanar to a top surface of the stopping layer and connects to the conductive structure.
27. A method of forming a gas dielectric with support structure comprising the steps of:
- providing a conductive structure in a wiring-layer dielectric;
- forming a support connected to the conductive structure, the support including an area thereunder; and
- removing the wiring-layer dielectric from the area to form a gas dielectric;
- wherein forming the support further comprises the steps of: forming a stopping layer on the wiring-layer dielectric; forming a sacrificial layer on the stopping layer; selectively removing a portion of the sacrificial layer, the stopping layer, and the wiring-layer dielectric for placement of the conductive structure; forming a vertical sacrificial spacer in the portion selectively removed to surround a portion of the conductive structure; forming the conductive structure between the vertical sacrificial spacer; partially removing the conductive structure; removing the sacrificial layer and a top portion of the vertical sacrificial spacer; and forming a support with the stopping layer and a material on the vertical sacrificial spacer, wherein the material is formed coplanar to a top surface of the stopping layer and connects to the conductive structure.
Type: Application
Filed: Oct 24, 2003
Publication Date: Apr 28, 2005
Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION (Armonk, NY)
Inventors: Toshiharu Furukawa (Essex Junction, VT), Mark Hakey (Fairfax, VT), David Horak (Essex Junction, VT), Charles Koburger (Delmar, NY), Peter Mitchell (Jericho, VT), Larry Nesbit (Williston, VT), James Slinkman (Montpelier, VT)
Application Number: 10/605,766