Abstract:
Methods for fabricating sub-resolution line space patterns are disclosed. In one embodiment, a method includes steps for fabricating a half-pitch pattern having equal line to space dimension. In other embodiments, method includes steps for fabricating a quarter-pitch pattern having equal line to space dimension. The disclosure also provides steps for fabricating small trench structures with spacers.
Abstract:
Spacers (175) in a pitch multiplication process are formed without performing a spacer etch. Rather, mandrels (145) are formed over a substrate (110) and then the sides of the mandrels (145) are reacted, e.g., in an oxidization, nitridation, or silicidation step, to form a material that can be selectively removed relative to the unreacted portions of the mandrel (145). The unreacted portions are selectively removed to leave a pattern of free- standing spacers (175). The free-standing spacers (175) can serve as a mask for subsequent processing steps, such as etching the substrate (110).
Abstract:
Methods of forming electrically conductive and/or semiconductive features for use in integrated circuits are disclosed. Various pattern transfer and etching steps can be used, in combination with pitch-reduction techniques, to create densely-packed features. The features can have a reduced pitch in one direction and a wider pitch in another direction. Conventional photo-lithography steps can be used in combination with pitch-reduction techniques to form elongate, pitch-reduced features such as bit-line contacts (732), for example. In some embodiments, contacts (732) can be formed by providing an insulating layer (334) that is overlaid by multiple layers of masking material. A series of selectively definable lines (124) can then be created in the masking material, where the lines have a pattern. Pitch reduction can then be performed on the lines using a spacer material (170) to create pitch-reduced masking lines (175) that are elongate along a spacer axis. Each pitch-reduced masking line (175) can thus be separated by a pitch-reduced space. A second pattern (e.g., that of the second mask 480) of photoresist that crosses a portion of the masking features can then be applied. The second pattern can have a window (482) that leaves multiple portions of the pitch-reduced masking lines (175) and adjacent pitch-reduced spaces uncovered by the photoresist. The window (482) can have an elongate axis that is not parallel to the elongate axis of the pitch-reduced masking lines. The insulating layer (334) can then be etched through a third pattern-defined, in part, by the pitch-reduced spaces-to create contact vias (584) in the insulating layer (334). The contact vias (584) can be filled with a conductive material to create electrical contacts (732).
Abstract:
A method of processing a thin film structure on a semiconductor substrate using an optically writable mask includes placing the substrate in a reactor chamber, the substrate having on its surface a target layer to be etched in accordance with a predetermined pattern, and depositing a carbon-containing hard mask layer on the substrate by (a) introducing a carbon-containing process gas into the chamber, (b) generating a reentrant toroidal RF plasma current in a reentrant path that includes a process zone overlying the workpiece by coupling plasma RF source power to an external portion of the reentrant path, and (c) coupling RF plasma bias power or bias voltage to the workpiece. The method further includes photolithographically defining the predetermined pattern in the carbon-containing hard mask layer, and etching the target layer in the presence of the hard mask layer.
Abstract:
A method for forming etch features in an etch layer over a substrate is provided. An etch mask stack is formed over the etch layer. A first mask is formed over the etch mask stack. A sidewall layer is formed over the first mask, which reduces the widths of the spaces defined by the first mask. A first set of features is etched into the etch mask stack through the sidewall layer. The mask and sidewall layer are removed. An additional feature step is performed, comprising forming an additional mask over the etch mask stack, forming a sidewall layer over the additional mask, etching a second set of features at least partially into the etch mask stack. A plurality of features is etched into the etch layer through the first set of features and the second set of features in the etch mask stack.
Abstract:
Methods of forming arrays of small, densely spaced holes or pillars for use in integrated circuits are disclosed. Various pattern transfer and etching steps can be used, in combination with pitch-reduction techniques, to create densely-packed features. Conventional photolithography steps can be used in combination with pitch-reduction techniques to form superimposed, pitch-reduced patterns of crossing elongate features that can be consolidated into a single layer.
Abstract:
A method for defining patterns in an integrated circuit (100) comprises defining a plurality of features in a first photoresist layer using photolithography over a first region (102) of a substrate (108). The method further comprises using pitch multiplication to produce at least two features (120) in a lower masking layer (116) for each feature in the photoresist layer. The features in the lower masking layer (116) include looped ends (124). The method further comprises covering with a second photoresist layer (126) a second region (104) of the substrate (108) including the looped ends (124) in the lower masking layer (116). The method further comprises etching a pattern of trenches in the substrate (108) through the features in the lower masking layer without etching in the second region (104). The trenches have a trench width.
Abstract:
Differently-sized features of an integrated circuit (100) are formed by etching a substrate (110) using a mask which is formed by combining two separately formed patterns (177) and (230). Pitch multiplication is used to form the relatively small features (175) of the first pattern (177) and conventional photolithography used to form the relatively large features of the second pattern (230). Pitch multiplication is accomplished by patterning a photoresist and then etching that pattern into an amorphous carbon layer. Sidewall spacers (175) are then formed on the sidewalls of the amorphous carbon. The amorphous carbon is removed, leaving behind the sidewall spacers (175), which define the first mask pattern (177). A bottom anti-reflective coating (BARC) is then deposited around the spacers (175) to form a planar surface and a photoresist layer is formed over the BARC. The photoresist is next patterned by conventional photolithography to form the second pattern (230), which is then is transferred to the BARC. The combined pattern (177, 230) made out by the first pattern (177) and the second pattern (230) is transferred to an underlying amorphous silicon layer (150) and the pattern is subjected to a carbon strip to remove BARC and photoresist material. The combined pattern (177, 230) is then transferred to the silicon oxide layer (155) and then to an amorphous carbon mask layer (160). The combined mask pattern (177, 230), having features of difference sizes, is then etched into the underlying substrate (110) through the amorphous carbon hard mask layer (160).
Abstract:
The present invention provides for a method to pattern and etch very small dimension pillars, for example in a memory array. When dimensions of pillars become very small, the photoresist pillars used to pattern them may not have sufficient mechanical strength to survive the photoresist exposure and development process. Using methods according to the present invention, these photoresist pillars are printed and developed larger than their intended final dimension, such that they have increased mechanical strength, then are shrunk to the desired dimension during a preliminary etch performed before the etch of underlying material begins.