Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
1998-08-19
2001-02-27
Utech, Benjamin L. (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S708000, C438S710000, C438S711000, C438S716000, C438S717000
Reexamination Certificate
active
06194321
ABSTRACT:
TECHNICAL FIELD
The invention pertains to semiconductor processing methods, such as, for example, methods of patterning photoresist in which an antireflective material is utilized to attenuate (for example, absorb) radiation. The invention also pertains to semiconductive wafer structures.
BACKGROUND OF THE INVENTION
Semiconductor processing frequently involves providing a photoresist layer over a substrate. Portions of the photoresist layer are subsequently exposed to light through a masked light source. The mask contains clear and opaque features defining a pattern to be created in the photoresist layer. Regions of the photoresist layer which are exposed to light are made either soluble or insoluble in a solvent. If the exposed regions are soluble, a positive image of the mask is produced in the photoresist. The photoresist is therefore termed a positive photoresist. On the other hand, if the non-irradiated regions are dissolved by the solvent, a negative image results. Hence, the photoresist is referred to as a negative photoresist.
A difficulty that can occur when exposing photoresist to radiation is that waves of radiation can propagate through the photoresist to a layer beneath the photoresist and then be reflected back up through the photoresist to interact with other waves propagating through the photoresist. The reflected waves can constructively and/or destructively interfere with other waves propagating through the photoresist to create periodic variations of light intensity within the photoresist. Such variations of light intensity can cause the photoresist to receive non-uniform doses of energy throughout its thickness. The non-uniform doses can decrease the accuracy and precision with which a masked pattern is transferred to the photoresist. Also, the radiated waves reflected back from a non-flat surface underlying photoresist can enter portions of the photoresist that are not supposed to be exposed. Accordingly, it is desired to develop methods which suppress radiation waves from being reflected by layers beneath a photoresist layer.
A method which has been used with some success to suppress reflected waves is to form an antireflective coating beneath a photoresist layer. Antireflective coatings can, for example, comprise materials which absorb radiation, and which therefore quench reflection of the radiation. Antireflective coatings absorb various wavelengths of radiation with varying effectiveness. The wavelengths absorbed, and the effectiveness with which they are absorbed, vary depending on the materials utilized. It would be desirable to develop additional materials for use as antireflective coatings.
SUMMARY OF THE INVENTION
In one aspect, the invention encompasses a semiconductor processing method wherein a layer comprising boron and nitrogen is formed over a substrate. A photoresist is formed over the layer comprising boron and nitrogen. One or more portions of the photoresist is exposed to light to pattern the photoresist.
In another aspect, the invention encompasses a semiconductor processing method wherein a layer comprising boron nitride is formed over a substrate. A layer of photoresist is formed over the layer comprising boron nitride. Portions of the photoresist are exposed to light while leaving other portions of the photoresist unexposed. Some of the light passes through the photoresist during the exposing. Light passing through the photoresist is absorbed with the layer comprising boron nitride. Either the exposed or unexposed portions of the photoresist are removed while leaving the other of the exposed and unexposed portions over the substrate to pattern the photoresist.
In yet another aspect, the invention encompasses a semiconductor wafer construction. The construction includes a layer comprising boron and nitrogen supported by a semiconductor substrate, and a photoresist layer over the layer comprising boron and nitrogen.
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DeBoer Scott Jeffrey
Moore John T.
Micro)n Technology, Inc.
Tran Binh X
Utech Benjamin L.
Wells St. John Roberts Gregory & Matkin
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