Abstract: A method to fabricate bottle-shaped deep trench into a semiconductor substrate. After a neck profile is formed, the chlorine gas at a predetermined flow rate is added to the etching plasma gas composition, while the flow rates of the plasma gases are increased by about 30% by volume, to create an enlarged lower portion of the deep trench. Preferably, the neck portion is etched using an etching composition which contains HBr, NF3, and (He/O2) provided at flow rates of about 87:13:35 sccm. The enlarged lower portion is etched using an etching composition which contains HBr, NF3, and (He/O2) provided at flow rates of about 113±12:17±2:46±5 sccm, and Cl2 provided at a flow rate between 10 and 40 sccm. It was found that the width of the lower portion of the deep trench can be increased by 100% with minimum side effects such as polymer deposition in the plasma chamber, which could occur as result of substantially increased flow rate of HBr and/or NF3.

Abstract: A method of fabricating deep trench capacitors of high density Dynamic Random Access Memory (DRAM) cells is disclosed: first, providing a semiconductor substrate, and then forming a trench on the semiconductor substrate; sequentially forming a capacitor dielectric layer, a first polysilicon storage node, dielectric collars and a second polysilicon stud inside the trench; performing two-step ion implantation to form shallow and deep strap regions on one side of the trench; forming a third polysilicon layer and an isolation layer overlaying the dielectric collars and second polysilicon stud inside the trench to complete a buried strap formation; and forming an access field effect transistor on the semiconductor substrate.

Abstract: An optical mask system for improving the bandwidth in the x-direction of an asymmetrical optical mask, wherein the optical mask has a pattern that varies strongly in the x-direction, but slowly in the y-direction, thus occupying a two-dimensional cigar-shaped area in the transformed Fx-Fy two-dimensional frequency domain. The apparatus and method of the present invention are most advantageous for preparing semiconductor devices whose topography varies strongly in one direction but weakly in another direction. The optical mask system includes: (a) a first diffractive light grating, tilted at a tilting angle &ohgr; relative to an incident light direction, wherein &ohgr; is about 45 degrees; (b) an asymmetric optical mask; (c) a second diffractive light grating, tilted at a tilting angle &phgr; relative to the incident light direction, wherein &phgr; is about 45 degrees; and (d) a low-pass filter.

Abstract: A track coater unit cup set for using in a wafer spin coating process comprises a hollow concave circular base cup, a hollow convex circular inner cup, and a hollow convex circular outer cup. The base cup has an inner circular groove with an inner groove wall and an eccentric outer circular groove with an outer circular groove wall. The inner cup capable of resting upon the base cup by engaging a downward protruding ring with the inner groove wall of the base cup on a meshing interface in between. The outer cup for shielding above top of the inner cup and capable of resting upon the base cup has a central top opening and a ring of inward tip extruding downward from an edge of the outer cup for forming the top opening. A stall-flow region is defined between the inward tip and adjacent insides of the outer cup. The meshing interface further includes at least a set of anchoring means for avoiding relative slipping between the base cup and the inner cup.

Abstract: A method to fabricate bottle-shaped deep trench in a semiconductor substrate which mainly involves two substitute plasma etching steps from the conventional approach. After a neck profile is formed, instead of raising the plasma gas pressure while keeping the etching composition constant, as in the conventional approach, the plasma gas pressure is first maintained the same, then decreased substantially. On the other hand, the concentrations of HBr and NF.sub.3 are increased substantially in both new steps. The first substitute plasma etching step is conducted at a pressure of 100 mtorr an RF power of about 1,000 W, a magnetic field of 65 Gauss. The plasma gas composition consists of HBr, NF.sub.3, and (He/O.sub.2) a at a ratio of about 200:20:20. The second substitute plasma etching step is conducted at plasma gas pressure of 30 mtorr, an RF power of 600 W, a magnetic field of 65 Gauss. The plasma gas composition consists of HBr, NF.sub.3, and (He/O.sub.2) a at a ratio of about 150:13:20.