Vlsi Technology, Inc.

Henry C Lee

Xi-Wei Lin

Ian Robert Harvey

Calvin T Gabriel

Satyendra S Sethi

Jie Zheng

A method for forming a semiconductor structure on an active area mesa with minimal loss of field oxide deposited in isolation trenches adjacent the mesa. The trench insulating material is protected by an etch barrier layer having at least a partial resistance to etchants used in further device processing steps. The barrier layer may also be deposited over the surface of the substrate to protect it from damage during device processing. The barrier layer may be removed by an etchant having a selectivity for the barrier layer over that of the surrounding device elements. Final processing of the device may be completed once the barrier layer is removed.

Method for fabrication of a semiconductor device

A method of removing an inorganic antireflective coating from a semiconductor substrate and a method of forming an integrated circuit (IC) are provided. In the former method, a sacrificial layer is formed over a semiconductor substrate, the layer being selectively removable from the substrate and compatible with photolithography. An inorganic antireflective coating such as SiON is then formed over the sacrificial layer. Thereafter, the sacrificial layer is removed from the substrate to lift the coating off the substrate. Preferred materials for the sacrificial layer include TiN, tetraethyl orthosilicate-based silicon oxide, spin-on-glass (SOG) such as hydrogen silsesquioxane and methyl silsesquioxane, and porous polymeric materials. In the latter method, a patterned layer of photoresist material is formed over the anitreflective coating. The portions of the antireflective coating, the sacrificial layer, and the semiconductor substrate which are not covered by the patterned layer of photoresist material are then removed to define features of an IC. After the patterning of IC features, the sacrificial layer is removed from the IC features to lift the antireflective coating off such features. IC devices formed in accordance with these methods also are provided.

Method of removing an inorganic antireflective coating from a

A method for monitoring contamination in a semiconductor wafer uses a capacitance-frequency measurement on MOS structures to calculate an impurity concentration. The silicon substrate along with an oxide layer is first biased into the inversion region using a variable frequency waveform generator superimposed upon a DC voltage bias. Next, the capacitance of the wafer is measured as a function of the varying frequency in order to develop a capacitance versus frequency curve. From this frequency response, a bandwidth (BW) is measured at a particular normalized capacitance point. The impurity concentration N is then derived using the formula N=G.times.BW, where G is the correlation constant. With an a priori knowledge of impurity concentration, N, the constant G may be derived by measuring a bandwidth of the capacitance versus frequency curve. Once the constant G is determined, future evaluation of impurity concentration can be made by a capacitance measurement. The method can be used on finished product wafers or as a routine monitoring tool on pre-processed wafers.

Contamination monitoring using capacitance measurements on MOS structures

Disclosed is a method for making a shallow trench structure in a semiconductor substrate. The method includes: (a) forming a mask over a semiconductor substrate, the mask being provided with an aperture extending therethrough which exposes a region of the semiconductor substrate, the aperture having substantially vertical sidewalls; (b) depositing a blanket of silicon over the mask and within the aperture; (c) anisotropically etching the deposited silicon to form temporary spacers having curved profiles at the sidewalls of the aperture, the temporary spacers transferring the curved profiles to a mouth of a shallow trench being etched at the region of the semiconductor substrate as the temporary spacers are etched away; (d) whereby a shallow trench structure is formed where the mouth has a curved profile.

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Henry C Lee