In a method for manufacturing a semiconductor device, a substrate is provided, and a dielectric layer is formed to cover the substrate. A recess portion is formed in the dielectric layer. A spacer is formed on a side surface of the recess portion. The dielectric layer is etched through the recess portion to form a hole in the dielectric layer to expose a portion of the substrate.

Disclosed is a method for selectively etching a first region made of silicon oxide to a second region made of silicon nitride. The method includes: performing a first sequence once or more to etch the first region; and performing a second sequence once or more to further etch the first region. The first sequence includes: a first step of generating plasma of a processing gas containing a fluorocarbon to form a fluorocarbon-containing deposit on a workpiece; and a second step of etching the first region by radicals of the fluorocarbon. The second sequence includes: a third step of generating plasma of a processing gas containing a fluorocarbon gas to form a fluorocarbon-containing deposit on a workpiece; and a fourth step of generating plasma of a processing gas containing oxygen gas and an inert gas in the processing container.

The present application discloses a method for fabricating a semiconductor device. The method includes providing a substrate comprising a central array area and a marginal array area surrounding the central array area; concurrently forming a first bit line above the central array area and a first dummy bit line above the marginal array area; and concurrently forming a second bit line above the central array area and a second dummy bit line above the marginal array area. The second bit line is higher than and offset from the first bit line and the second dummy bit line is directly above the first dummy bit line.

The present disclosure provides a method for preparing a semiconductor structure. The method includes forming a conductive structure over a semiconductor substrate, and forming a first inter-layer dielectric (ILD) layer over the conductive structure. The method also includes forming a first spacer and a conductive plug penetrating through the first ILD layer. The conductive plug is electrically connected to the conductive structure, and the first spacer is between the first ILD layer and the conductive plug. The method further includes removing a portion of the first ILD layer to form a gap adjacent to the first spacer, and filling the gap with an energy removable material. In addition, the method includes performing a heat treatment process to transform the energy removable material into a second spacer, wherein the first spacer is separated from the first ILD layer by an air gap after the heat treatment process is performed.

The present disclosure provides a method for preparing a semiconductor memory device with air gaps between conductive features. The method includes forming an isolation layer defining a first active region in a substrate; forming a first doped region in the first active region; forming a first word line buried in a first trench adjacent to the first doped region; and forming a high-level bit line contact positioned on the first doped region; forming a first air gap surrounding the high-level bit line contact. The forming of the first word line comprises: forming a lower electrode structure and an upper electrode structure on the lower electrode structure. The forming of the upper electrode structure comprises: forming a source layer substantially covering a sidewall of the first trench; forming a conductive layer on the source layer; and forming a work-function adjustment layer disposed between the source layer and the conductive layer.

A semiconductor device includes a substrate, a conductive pattern, a side spacer, and an air gap. The substrate includes an interlayer insulating layer and a trench penetrating the interlayer insulating layer. The conductive pattern is disposed within the trench of the substrate. The side spacer is disposed within the trench. The side spacer covers an upper side surface of the conductive pattern. The air gap is disposed within the trench. The air gap is bounded by a sidewall of the trench, the side spacer, and a lower side surface of the conductive pattern. A level of a bottom surface of the conductive pattern is lower than a level of bottom surfaces of the side spacer.

In the present method, a substrate to be processed, having an interlayer insulation film, is prepared (step 1). The interlayer insulation film is subjected to dry etching, while using a mask layer, thereby forming recesses (step 2). Residue is removed by dry ashing (step 3). A coating is formed on the entire surface by means of a gas process using a coating compound gas, with a molecular structure having at one terminal a first substitution group that reacts with and bonds with the surface of the interlayer insulation film, and at the other terminal a second substitution group that is hydrophilic (step 4). The coating is removed by wet cleaning (step 5). Wiring is formed in the recesses (step 6).

An etching method and a fabrication method of semiconductor structures are provided. The etching method includes forming trenches in a to-be-etched structure, and forming a dielectric layer in the trenches. The etching method further includes etching the dielectric layer in the trenches by an etching process, and controlling at least an etching temperature of the etching process while a polymer is formed on side surface of the to-be-etched structure. During the etching process of the dielectric layer, the polymer undergoes a deposition stage and a removal stage. The deposition stage has a deposition rate of the polymer greater than an etch rate of the polymer, and the removal stage has the deposition rate of the polymer less than the etch rate of the polymer.

A semiconductor device includes: a first plug; a bit line which is in contact with the first plug and over the first plug and extended in one direction; a second plug including a first part adjacent to the bit line and a second part adjacent to the first plug; a double air gap which is disposed between the first part of the second plug and the bit line and includes a first air gap surrounding the first part of the second plug and a second air gap parallel to sidewalls of the bit line; and a capping layer suitable for capping the first and second air gaps.

A semiconductor device includes an active fin formed to extend in a first direction, a gate formed on the active fin and extending in a second direction crossing the first direction, a source/drain formed on upper portions of the active fin and disposed at one side of the gate, an interlayer insulation layer covering the gate and the source/drain, a source/drain contact passing through the interlayer insulation layer to be connected to the source/drain and including a first contact region and a second contact region positioned between the source/drain and the first contact region, and a spacer layer formed between the first contact region and the interlayer insulation layer. A width of the second contact region in the first direction is greater than the sum of a width of the first contact region in the first direction and a width of the spacer layer in the first direction.