Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
111 words
A method of manufacturing a semiconductor device comprising a silicon substrate with fully or partly sunken field oxide regions for mutual insulation of semiconductor elements to be formed in the substrate, in which a mask is formed in a layer of silicon oxynitride (SiO x N y ) extending over a surface of the substrate and an overlying layer of silicon nitride (Si₃N₄), after which, using said mask, recesses are first provided in the substrate in which recesses the field oxide regions are then formed by oxidation, characterized in that the recesses are provided in the substrate by performing a first oxidation and then etching away the silicon oxide thus formed.
Claim 2
Independent Claim
111 words
A method of manufacturing a semiconductor device comprising a silicon substrate with fully or partly sunken field oxide regions for mutual insulation of semiconductor elements to be formed in the substrate, in which a mask is formed in a layer of silicon oxynitride (SiO x N y ) extending over a surface of the substrate and an overlying layer of silicon nitride (Si₃N₄), after which, using said mask, recesses are first provided in the substrate in which recesses the field oxide regions are then formed by oxidation, characterized in that the recesses are provided in the substrate by performing a first oxidation and then etching away the silicon oxide thus formed.
Claim 3
Dependent Claim
36 words
A method as claimed in Claim 1, characterized in that the mask is provided as a 30 to 60 nm thick layer of silicon oxynitride and a 50 to 200 nm thick layer of silicon nitride.
Claim 4
Dependent Claim
52 words
A method as claimed in Claim 1 or 2, characterized in that in the first oxidation step a layer of silicon oxide is formed in a thickness smaller than the thickness of the layer of silicon oxide which is formed with the oxidation step for the formation of the field oxide regions.
Claim 5
Dependent Claim
55 words
A method as claimed in Claim 1, 2 or 3, characterized in that with the first oxidation step a 150 to 600 nm thick layer of silicon oxide is formed and with the oxidation step for the formation of the field oxide regions a 200 to 800 nm thick layer of silicon oxide is formed.
Claim 6
Independent Claim
48 words
A method as claimed in one or more of the preceding Claims, characterized in that the layer of silicon oxide formed with the first oxidation step is etched away isotropically in a buffer solution of one part of hydrogen fluoride (HF) in seven parts of ammonium fluoride (NH₄F).
Claim 7
Independent Claim
87 words
A method as claimed in one or more of the preceding Claims, characterized in that prior to performing the first oxidation step a further layer of silicon oxynitride (SiO x N y ) is provided on the mask after which the said further layer of silicon oxynitride is etched anisotropically in such a manner that the edges of the apertures of the mask which bound the regions of the substrate where the recesses are provided remain covered with parts of the said further layer of silicon oxynitride.
Claim 8
Dependent Claim
24 words
A method as claimed in Claim 6, characterized in that the further silicon oxynitride is provided in a thickness of 40 to 60 nm.