Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2002-09-11
2004-08-03
Huff, Mark F. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S914000, C430S905000, C430S326000, C430S910000, C430S313000, C430S316000, C430S317000, C430S318000, C430S328000, C430S323000, C430S331000
Reexamination Certificate
active
06770419
ABSTRACT:
BACKGROUND OF THE INVENTION
In the microelectronics industry as well as in other industries involving construction of microscopic structures (e.g. micromachines, magnetoresistive heads, etc.), there is a continued desire to reduce the size of structural features. In the microelectronics industry, the desire is to reduce the size of microelectronic devices and/or to provide greater amount of circuitry for a given chip size.
Effective lithographic techniques are essential to achieving reduction of feature sizes. Lithography impacts the manufacture of microscopic structures not only in terms of directly imaging patterns on the desired substrate, but also in terms of making masks typically used in such imaging. Typical lithographic processes involve formation of a patterned resist layer by patternwise exposing the radiation-sensitive resist to an imaging radiation. The image is subsequently developed by contacting the exposed resist layer with a material (typically an aqueous alkaline developer) to selectively remove portions of the resist layer to reveal the desired pattern. The pattern is subsequently transferred to an underlying material by etching the material in openings of the patterned resist layer. After the transfer is complete, the remaining resist layer is then removed.
The resolution capability of lithographic processes is generally a function of the wavelength of imaging radiation, the quality of the optics in the exposure tool and the thickness of the imaging layer. As the thickness of the imaging resist layer increases, the resolution capability decreases. Thinning of a conventional single layer resist to improve resolution generally results in compromise of the etch resistance of the resist which is needed to transfer the desired image to the underlying material layer. In order to obtain the resolution enhancement benefit of thinner imaging layers, multilayer lithographic processes (e.g., so-called bilayer process) have been developed. In multilayer lithographic processes, a so-called planarizing underlayer is used intermediate between the imaging resist layer (typically a silicon-containing resist) and the underlying material layer to be patterned by transfer from the patterned resist. The underlayer receives the pattern from the patterned resist layer, and then the patterned underlayer acts as a mask for the etching processes needed to transfer the pattern to the underlying material.
The imaging layer of a bilayer or multilayer resist process typically uses a silicon-containing acid-sensitive polymer. The silicon content acts to provide differential etch characteristics relative to the planarizing underlayer (which is typically free of silicon). Typically, the silicon-containing resist polymer contains at least about 5 or 6 wt. % silicon.
In addition to having significant silicon content, the imaging layer resist composition must also possess the desired lithographic performance with the imaging radiation of interest. With the continued move toward higher resolution lithography, the imaging radiation of interest is quickly becoming 193 nm wavelength (ArF) ultraviolet radiation and is expected to become 157 nm (F
2
) ultraviolet radiation. Thus, the respective silicon-containing resists for use at these wavelengths must possess desirable optical characteristics and dissolution behavior (i.e., selective dissolution of exposed areas) to enable image resolution at a desired radiation wavelength. Given the extensive experience in the lithographic arts with the use of aqueous alkaline developers, it is important and highly desirable to achieve appropriate dissolution behavior in such commonly used developer solutions.
The general approach in developing resist for bilayer applications has largely been to place the required silicon content on the acid-sensitive imaging polymer in the form of acid labile silicon-containing moieties. This approach has generally resulted in resist compositions which release undesired volatile silicon compounds (outgassing) during the lithographic process. These volatile silicon compounds may deposit on sensitive portions of the lithographic equipment (e.g., lenses, etc.) leading to need for early replacement of expensive components, downtime for extra tool maintenance, etc. Thus, there is a desire for silicon-containing resist formulations where silicon outgassing is reduced or eliminated.
SUMMARY OF THE INVENTION
The invention provides silicon-containing resist compositions which have low silicon outgassing and high resolution lithographic performance, especially in bilayer or multilayer lithographic applications using 193 nm or shorter wavelength imaging radiation. The resist compositions of the invention are generally characterized by the presence of an imaging polymer having silicon-containing, non-acid-labile pendant groups. The resist compositions of the invention are preferably further characterized by the substantial absence of silicon-containing acid-labile moieties.
In one aspect, the invention encompasses a silicon-containing resist composition comprising:
(a) an acid-sensitive imaging polymer, and
(b) a radiation-sensitive acid generator,
wherein the acid-sensitive imaging polymer comprises a silicon-containing non-acid-labile pendant group.
The imaging polymer is preferably useful in 193 nm lithographic processes and preferably the contains substantially no silicon-containing acid-labile moieties. The silicon-containing, non-acid-labile pendant groups are preferably further characterized by the presence of a direct bond between a silicon atom of the pendant group and (i) a carbon atom of an ethylenic moiety forming part of a backbone of the imaging polymer or (ii) a carbon atom of a cyclic olefin moiety forming part of a backbone of the imaging polymer.
In another aspect, the invention encompasses a method of forming a patterned material structure on a substrate, the material being selected from the group consisting of semiconductors, ceramics and metals, the method comprising:
(A) providing a substrate with a layer of the material,
(B) forming a planarizing layer over the material layer,
(C) applying a resist composition over the planarizing layer to form a resist layer, the resist composition comprising:
(a) an acid-sensitive imaging polymer, and
(b) a radiation-sensitive acid generator,
wherein the acid-sensitive imaging polymer comprises a silicon-containing non-acid-labile pendant group,
(D) patternwise exposing the substrate to radiation whereby acid is generated by the radiation-sensitive acid generator in exposed regions of the resist layer by the radiation,
(E) contacting the substrate with an aqueous alkaline developer solution, whereby the exposed regions of the resist layer are selectively dissolved by the developer solution to reveal a patterned resist structure,
(F) transferring resist structure pattern to the planarizing layer, by etching into the planarizing layer through spaces in the resist structure pattern, and
(G) transferring the structure pattern to the material layer, by etching into the material layer through spaces in the planarizing layer pattern.
The etching of step (G) is preferably reactive ion etching. The imaging radiation preferably has a wavelength of about 193 nm. The substrate is preferably baked between steps (D) and (E).
These and other aspects of the invention are discussed in further detail below.
DETAILED DESCRIPTION OF THE INVENTION
The resist compositions of the invention are generally characterized by the presence of an imaging polymer having silicon-containing, non-acid-labile pendant groups. The resist compositions of the invention are preferably further characterized by the substantial absence of silicon-containing acid-labile moieties. These compositions exhibit low silicon outgassing and are especially capable of providing high resolution lithographic patterns in bilayer or multilayer lithographic processes. The invention further encompasses processes for creating and using patterned resist structures based on the resist compositions of the invention to form conductive, se
Allen Robert D.
Brock Phillip
Chen Kuang-Jung
Houle Frances
Khojasteh Mahmoud M.
Capella Steven
Huff Mark F.
International Business Machines - Corporation
Lee Sin J.
LandOfFree
Low silicon-outgassing resist for bilayer lithography does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low silicon-outgassing resist for bilayer lithography, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low silicon-outgassing resist for bilayer lithography will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3301791