Stmicroelectronics S.r.l.

Sgs-Thomson Microelectronics S.r.l.

Elio Colabella

Luca Pividori

Emilio Camerlenghi

Maurizio Bacchetta

Patrizia Sonego

Adriana Rebora

A method of depositing a dielectric ply structure to optimize the planarity of electronic devices that include a plurality of active elements having gate regions laid across the substrate as discrete parallel lines, such as the bit lines of memory cells. In accordance with the principles of the present invention, the plurality of bit lines may be isolated from one another by the dielectric ply structure to provide a planar architecture onto which an optional conductive layer may be deposited. The resulting planarization avoids the typical shortcomings of the prior art, such as the lack of electrical continuity in the word lines or their excessively high electrical resistance from slenderized portions in the conductive sections due to poor planarity of the surfaces upon which the conductive layer is deposited.

Planarization structure and method for dielectric layers

Self-aligned etching process for providing a plurality of mutually parallel word lines in a first conducting layer deposited over a plagiarized architecture obtained starting from a semiconductor substrate on which is provided a plurality of active elements extending along separate parallel lines e.g., memory cell bit lines and comprising gate regions made up of a first conducting layer, an intermediate dielectric layer and a second conducting layer with said regions being insulated from each other by insulation regions to form said architecture with said word lines being defined photolithographically by protective strips implemented by means of: a vertical profile etching for complete removal from the unprotected areas of the first conducting layer of the second conducting layer and of the intermediate dielectric layer respectively, and a following isotropic etching of the first conducting layer.

Autoaligned etching process for realizing word lines in memory devices integrated semiconductor substrates

An improved method of making semiconductor memory structures that include a memory matrix having non-volatile memory cells, each with a floating gate transistor and a selection transistor, each transistor provided with a gate electrode. Associated with the memory matrix is control circuitry, which also have control gates. The method includes forming the gate electrodes on top of the semiconductor substrate and then depositing a dielectric layer over the whole memory structure. A screening layer is deposited over the whole surface of the memory structure, and then part of it is removed, exposing a portion of the control circuitry. A portion of the dielectric layer is etched away in the non-covered portion of the control circuitry to form spacer regions, and the non-covered portion of the control circuitry is then implanted with a dopant.

Method for forming non volatile memory structures on a semiconductor substrate

A process of manufacturing cross-point matrix memory devices which have floating gate memory cells having the source channel self-aligned to the bit line and the field oxide is disclosed. The process includes the steps of growing a thin layer of tunnel oxide on the matrix region; depositing a stack structure comprising a first conductive layer, an intermediate dielectric layer, and a second conductive layer; photolithographing with a Polyl mask to define a plurality of parallel floating gate regions in the stack structure; self-aligned etching of the stack structure, above the active areas, to define continuous bit lines; and implanting, to confer predetermined conductivity on the active areas . Advantageously, the self-aligned cascade etching step for removing parallel strips from multiple layers, down to the active areas of the substrate, is discontinued before the field oxide is removed, and the implantation step is carried out in the presence of field oxide over the source active areas.

Process for making crosspoint memory devices with cells having a source channel which is autoaligned to the bit line and to the field oxide

The process proposed allows provision of a matrix topography for electronic memory devices using self-alignment etchings capable of removing those spurious electrical contacts between adjacent memory cells. The self-aligned etching process proposed for providing a plurality of mutually parallel word lines in a first conducting layer deposited over a planarized architecture obtained starting from a semiconductor substrate. Provided on the semiconductor substrate is a plurality of active elements extending along separate parallel lines, e.g., memory cell bit lines, and comprising gate regions formed by a first conducting layer, a dielectric interpoly layer and a second conducting layer with said regions being insulated from each other by dielectric insulation films to form said architecture with said word lines being defined photolithographically by protective strips. The etching process includes: a vertical profile etching for complete removal from the unprotected areas respectively of the first conducting layer, of the second conducting layer of the gate region; a successive etching of the dielectric interpoly layer accompanied by a considerable erosion of the dielectric film of the insulation region so as to totally uncover the first conducting layer, and a concluding etching of the first conducting layer.

Autoaligned etching process for realizing word lines and improving the reliability of semiconductor integrated memory devices

Method of planarizing a semiconductor device by depositing a dielectric

Self-aligned etching process for providing a plurality of mutually parallel word lines in a first conducting layer deposited over a planarized architecture obtained starting from a semiconductor substrate on which is provided a plurality of active elements extending along separate parallel lines e.g., memory cell bit lines and comprising gate regions made up of a first conducting layer, an intermediate dielectric layer and a second conducting layer with said regions being insulated from each other by insulation regions to form said architecture with said word lines being defined photolithographically by protective strips implemented by means of: a vertical profile etching for complete removal from the unprotected areas of the first conducting layer of the second conducting layer and of the intermediate dielectric layer respectively, and a following isotropic etching of the first conducting layer.

Autoaligned etching process for realizing word lines in memory devices

A process of manufacturing cross-point matrix memory devices which have floating gate memory cells having the source channel self-aligned to the bit line and the field oxide is disclosed. The process includes the steps of growing a thin layer of tunnel oxide on the matrix region; depositing a stack structure comprising a first conductive layer, an intermediate dielectric layer, and a second conductive layer; photolithographing with a Poly1 mask to define a plurality of parallel floating gate regions in the stack structure; self-aligned etching of the stack structure, above the active areas, to define continuous bit lines; and implanting, to confer predetermined conductivity on the active areas. Advantageously, the self-aligned cascade etching step for removing parallel strips from multiple layers, down to the active areas of the substrate, is discontinued before the field oxide is removed, and the implantation step is carried out in the presence of field oxide over the source active areas.

Process for making crosspoint memory devices with cells having a source

A method of depositing a layered dielectric structure to improve the planarity of electronic devices which include a plurality of active elements having gate regions laid across the substrate as discrete parallel lines, such as the bit lines of memory cells. The bit lines are isolated from one another by a layered dielectric structure to provide a planar architecture onto which an optional conductive layer may be deposited. The dielectric structure is formed from a highly planarizing dielectric layer of the SOG type spun over a first insulating dielectric layer and solidified by means of a thermal polymerization process. After solidifying the dielectric layer, it is subjected to a rapid thermal annealing treatment.

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Milan, Italy

Elio Colabella