Semiconductor device manufacturing: process – Formation of electrically isolated lateral semiconductive... – Having air-gap dielectric
Reexamination Certificate
1997-08-11
2001-07-31
Lee, Eddie C. (Department: 2815)
Semiconductor device manufacturing: process
Formation of electrically isolated lateral semiconductive...
Having air-gap dielectric
C438S421000, C438S619000, C438S411000, C257S522000
Reexamination Certificate
active
06268262
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of forming air bridges on electronic devices. The method uses amorphous silicon carbide to protect the conductors on the device during and after the air bridge formation.
The electronics industry continues to strive to decrease the size of devices. One of the difficulties in the process of miniaturization is maintaining a sufficient dielectric between conductors to prevent device failure.
To solve this problem, the industry has investigated a wide variety of low dielectric constant materials. These materials have shown to provide dielectric constants of about 2 and above. Unfortunately, many of these materials are difficult to process and their chemical and physical properties can be incompatible with the devices.
One of the best dielectrics available is simply air. Various investigators have attempted to capitalize on this by leaving voids between adjacent conductors. These voids are often called “air bridges”. For instance, Fitch et al. in U.S. Pat. No. 5,324,683 describe the formation of an air bridge in an integrated circuit by removing all or a portion of a dielectric layer between conductors. The methods, materials and final product described therein, however, are different than those of the present invention.
The present invention has now discovered a method for forming an air bridge which uses the properties of silicon carbide in its formation and has the unexpected advantage of being more durable after formation.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a method for forming an air bridge on an electronic device. The method comprises first forming 2 separate conductors on an electronic device. These conductors have edges which are laterally adjacent to each other and the conductors are separated by a void. Next amorphous silicon carbide coatings are formed on the edges of the conductors which are laterally adjacent to each other such that the size of the void is decreased by the thickness of the coatings yet still leaving a void therebetween. Next, a sacrificial material is formed in the void between the laterally adjacent amorphous silicon carbide coated surfaces on the conductors. An amorphous silicon carbide coating is then formed on the sacrificial material. This coating is formed so that it contacts the amorphous silicon carbide coatings on the edges of the conductors and, thereby, encapsulates the sacrificial material in amorphous silicon carbide. The conductive bridge is then formed to electrically connect the conductors. This bridge is formed on the 2 conductors and the amorphous silicon carbide coating covering the sacrificial material. An amorphous silicon carbide coating is then deposited to cover the conductive bridge. Finally, the sacrificial material is etched to leave an air bridge between the silicon carbide on the conductors.
REFERENCES:
patent: 5324683 (1994-06-01), Fitch et al.
patent: 5354695 (1994-10-01), Leedy
patent: 5454904 (1995-10-01), Ghezzo et al.
patent: 5497033 (1996-03-01), Fillion et al.
patent: 5668398 (1997-09-01), Havemann et al.
patent: 5674758 (1997-10-01), McCarthy
patent: 6109106 (2000-08-01), Ferrari et al.
Brock II Paul E
Dow Corning Corporation
Lee Eddie C.
Severance Sharon K.
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