Abstract: The invention relates to a process for protection of the grid of a transistor in an integrated circuit for production of a local interconnection pad straddling over the grid and the silicon substrate on which it is formed. The process consists of applying a double dielectric-conducting layer on the transistor grid into which a polysilicon layer is added in order to use the selectivity principle, which is large considering the etching of polysilicon with respect to the oxide in which the local interconnection pad is formed. Furthermore, with the process according to the invention, a silicidation treatment can be applied beforehand on the active areas of the transistor and the grid.

Abstract: Prior fabricating the transistors, a phase of forming a deep insulative trench in the substrate is followed by a phase of forming a shallow insulative trench in the substrate and extending the deep trench. The phase of forming the deep trench includes coating the inside walls of the deep trench with an initial oxide layer and filling the deep trench with silicon inside an envelope formed from an insulative material. The phase of forming the shallow trench includes coating the inside walls of the shallow trench with an initial oxide layer and filling the shallow trench with an insulative material.

Abstract: An isolation trench formed in a semiconductor substrate has side walls and a bottom wall. Spacers are on the side walls and face each other for forming a narrow channel therebetween. The bottom wall and the spacers are coated with an electrically insulating material for delimiting a closed empty cavity in the channel. The isolation trench is applicable to the manufacture of integrated circuits.

Abstract: The invention relates to a process for protection of the grid of a transistor in an integrated circuit for production of a local interconnection pad straddling over the grid and the silicon substrate on which it is formed. The process consists of applying a double dielectric-conducting layer on the transistor grid into which a polysilicon layer is added in order to use the selectivity principle, which is large considering the etching of polysilicon with respect to the oxide in which the local interconnection pad is formed. Furthermore, with the process according to the invention, a silicidation treatment can be applied beforehand on the active areas of the transistor and the grid.

Abstract: The invention relates to a DRAM integration method that does away with the alignment margins inherent to the photoetching step of the upper electrode of the capacitance for inserting the bit line contact. The removal of the upper electrode is self-aligned on the lower electrode of the capacitance. This is accomplished by forming a difference in topography at the point where the opening of the upper electrode is to be made, and depositing a non-doped polysilicon layer on the upper electrode. An implantation of dopants is performed on this layer, and the part of the non-doped layer located in the lower part of the zone showing the difference in topography is selectively etched. The remainder of the polysilicon layer and the part of the upper electrode located in the lower layer are also etched.

Abstract: Prior fabricating the transistors, a phase of forming a deep insulative trench in the substrate is followed by a phase of forming a shallow insulative trench in the substrate and extending the deep trench. The phase of forming the deep trench includes coating the inside walls of the deep trench with an initial oxide layer and filling the deep trench with silicon inside an envelope formed from an insulative material. The phase of forming the shallow trench includes coating the inside walls of the shallow trench with an initial oxide layer and filling the shallow trench with an insulative material.

Abstract: A boro-silicate-glass (BSG) is deposited on a silicon substrate coated with a bottom SiO2 and an overlying Si3N4 layer by LPCVD using an O3/TEB/TEOS mixture at low pressure (less than 300 mTorr), low temperature (less than 500° C.) and a TEB flow which is adjusted to have a boron concentration in the BSG layer less than 10% (in weight). The BSG material deposited that way has been found to be resistant to aggressive silicon dry etch chemistries and is easily and rapidly etched in standard BSG etchants. However, very high etch rates are obtained with a HF/ethylene glycol wet chemistry. The disclosed BSG deposition method finds a valuable application in the fabrication of the buried plate in deep trench cell capacitors because no undercuts are produced in the bottom SiO2 layer sidewall exposed in the trench during the BSG layer removal.

Abstract: An improved method of forming the buried plate regions in deep trench capacitors used in DRAM memory semiconductor circuits in which the polymer used in the deep trench is etched down to the desired depth in a reactive ion etch tool using an O2/CF4 chemistry. Since optical/interferometric etch end-point detection system can be used to monitor the etch back step in its totality, the quantity of the polymer remaining in deep trenches can be very accurately controlled, which in turn will produce a well controlled buried plate region during the out-diffusion step of the arsenic dopant contained in the arsenic doped silicon glass layer.