Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Reexamination Certificate
1998-11-13
2001-04-24
Huff, Mark F. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
C430S323000, C430S324000
Reexamination Certificate
active
06221562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention pertains to semiconductor IC processing. In particular, this invention provides a method for achieving small line width control over semiconductor dimensions, thereby achieving greater feature density during IC manufacturing.
2. Background Art
It is an object of the present invention to convert a photoresist space pattern into a photoresist line pattern. An example of this is the use of a hybrid photoresist space image for gate conductor applications. A subtractive etch is currently used to form the gate, which requires a photoresist line rather than a photoresist space. In order to form the gate conductor from the hybrid space, the space must be converted to a line.
Previously used processes etched the photoresist space into a hard mask, then filled the hard mask with another material, such as silicon oxide. The oxide film is then polished, and the nitride hard mask stripped. The polished oxide can then be used to mask the gate conductor etch.
SUMMARY OF THE INVENTION
By means of our invention, we can take the sub-critical high-resolution space of a hybrid photoresist and turn it into a line. The line, formed in the manner of the present invention, can be used to mask a subtractive etch process on the substrate. The preferred application for this process at the present time is for conventional gate structure formation, in which a small channel length and high channel uniformity would provide a large beneficial gain.
Our solution is to apply a spun-on-glass oxide film over the photoresist. The spun-on-glass can be of the conventional spin-on type, or it can also be of the new plasma deposited type. The plasma deposition might be more reliable from the point of view of repeatability of applied thickness over time, and reduced defects due to shelf-life degradation of conventional spun-on-glass. This spun-on-glass material is desirable for this application because it fills very narrow openings well, leaving a minimal amount of material on the top of the topography. It can also be cured to a solid at relatively low temperatures of 150-170° C., which is compatible with avoiding photoresist degradation. After curing at these temperatures, the surface oxide can be etched, and the photoresist stripped, to leave an oxide line in place of the photoresist space. The oxide mask can then be used to etch the substrate, such as a gate conductor feature.
A gate structure formed in this manner is uniquely characteristic of a hybrid photoresist. It has a unique resolution and uniformity relative to conventional gate structures, since it does not have the normal image size distribution due to expose variation and mask variation present in conventional structures. It also provides unique image placement advantages, as the expose variation and mask variations typically present problems for image placement.
The present solution also eliminates an etch step, a polish step, and the nitride strip required in the hard mask process mentioned above. Other features and advantages of this invention will become apparent from the following detailed description of the presently preferred embodiment of the invention, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4774164 (1988-09-01), Peavey
patent: 5077236 (1991-12-01), Kim
patent: 5312512 (1994-05-01), Allman et al.
patent: 5451543 (1995-09-01), Woo et al.
patent: 5543252 (1996-08-01), Shibata et al.
patent: 5605783 (1997-02-01), Revelli et al.
patent: 5618383 (1997-04-01), Randall
patent: 5652182 (1997-07-01), Cleeves
patent: 5653851 (1997-08-01), Shelton
patent: 6017810 (2000-01-01), Furukawa
patent: 6096458 (2000-08-01), Hibbs
patent: 2-214126 (1990-08-01), None
Boyd Diane C.
Furukawa Toshiharu
Holmes Steven J.
Horak David V.
Ma William H.
Barreca Nicole
Huff Mark F.
International Business Machines - Corporation
Shkurko Eugene I.
LandOfFree
Resist image reversal by means of spun-on-glass does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Resist image reversal by means of spun-on-glass, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resist image reversal by means of spun-on-glass will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2497743