Semiconductor constructions having antireflective portions

#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.

#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 dose 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.

#Preferred embodiments of the invention are described below with reference to the following accompanying drawings.

#FIG. 1 is a fragmentary, diagrammatic, cross-sectional view of a semiductor wafer fragment at a preliminary processing step of a method of the present invention:

#FIG. 2 is a view of the FIG. 1 wafer fragment at a processing step subsequent to that shown in FIG. 1.

#This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).

#A method of the present invention is described with reference to FIGS. 1-3. Referring to FIG. 1, a semiconductor wafer fragment 10 is illustrated at a preliminary processing step. Wafer fragment 10 comprises a substrate 12, an overlying antireflective material layer 14, and a photoresist layer 16 over the antireflective material layer 14. The substrate can comprise, for example, a monocrystalline silicon wafer lightly doped with a conductivity-enhancing dopant. To aid in interpretation of this disclosure and the claims that follow, the term “semiconductive substrate” is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above.

#The antireflective material layer 14 can comprise an inorganic material, such as, for example, a material comprising from about 5% to about 37% (by atomic concentration) oxygen, about 10% to about 35% (by atomic concentration) nitrogen, from about 50% to about 65% (by atomic-concentration) silicon, and hydrogen. A specific example inorganic material comprises about 10% (by atomic concentration) nitrogen, about 25% (by atomic concentration) oxygen and about 65% (by atomic concentration) silicon. Antireflective coating layer 14 can, for example, consist of a single substantially homogeneous layer of the above-described inorganic material.