Semiconductor device with STI and its manufacture
First Claim
1. A semiconductor device comprising:
- a silicon substrate;
an isolation trench formed in said silicon substrate for isolating n-type and p-type active regions in said silicon substrate, said isolation trench having a trapezoidal cross sectional shape having a width gradually narrowing with a depth from a surface of said silicon substrate;
a first liner insulating film formed on a surface of said trench surrounding said n-type and p-type active regions and made of a silicon oxide film or a silicon oxynitride film having a thickness of 1 to 5 nm;
a second liner insulating film formed on said first liner insulating film surrounding said n-type and p-type active regions and made of a silicon nitride film having a thickness of 2 to 8 nm; and
an isolation region burying said trench defined by said second liner insulating film;
an n-channel MOS transistor formed in said p-type active region;
a p-channel MOS transistor formed in said n-type active region;
wherein an upper end of said second liner insulating film is retracted by less than about 10 nm from the surface of said silicon substrate;
wherein said second liner insulating film has a tensile stress of 1 GPa or larger; and
wherein said first and second liner insulating films extend from side walls of said trench to partially overlay an upper surface of the silicon substrate.
3 Assignments
0 Petitions
Accused Products
Abstract
A semiconductor device includes: a silicon substrate with semiconductor elements; an isolation trench formed in the silicon substrate for isolating active regions in the silicon substrate, the isolation trench having a trapezoidal cross sectional shape having a width gradually narrowing with a depth from the surface of the silicon substrate; a first liner insulating film formed on the surface of the trench and made of a silicon oxide film or a silicon oxynitride film having a thickness of 1 to 5 nm; a second liner insulating film formed on the first liner insulating film and made of a silicon nitride film having a thickness of 2 to 8 nm; and an isolation region burying the trench defined by the second liner insulating film.
24 Citations
17 Claims
-
1. A semiconductor device comprising:
-
a silicon substrate;
an isolation trench formed in said silicon substrate for isolating n-type and p-type active regions in said silicon substrate, said isolation trench having a trapezoidal cross sectional shape having a width gradually narrowing with a depth from a surface of said silicon substrate;
a first liner insulating film formed on a surface of said trench surrounding said n-type and p-type active regions and made of a silicon oxide film or a silicon oxynitride film having a thickness of 1 to 5 nm;
a second liner insulating film formed on said first liner insulating film surrounding said n-type and p-type active regions and made of a silicon nitride film having a thickness of 2 to 8 nm; and
an isolation region burying said trench defined by said second liner insulating film;
an n-channel MOS transistor formed in said p-type active region;
a p-channel MOS transistor formed in said n-type active region;
wherein an upper end of said second liner insulating film is retracted by less than about 10 nm from the surface of said silicon substrate;
wherein said second liner insulating film has a tensile stress of 1 GPa or larger; and
wherein said first and second liner insulating films extend from side walls of said trench to partially overlay an upper surface of the silicon substrate. - View Dependent Claims (2, 3)
-
-
4. A method of manufacturing a semiconductor device, comprising steps of:
-
(a) forming a polishing stopper layer on a surface of a silicon substrate, said stopper layer including a lower silicon oxide film and an upper silicon nitride film;
(b) etching said stopper layer and the silicon substrate by using a mask to form a trench;
(c) forming a first liner insulating film on a surface of the silicon substrate exposed in said trench, said first liner insulating film being a silicon oxide film or a silicon oxynitride film having a thickness of 1 to 5 nm;
(d) forming a second liner insulating film on said first liner insulating film, said second liner insulating film being made of a silicon nitride film having a thickness of 2 to 8 nm;
(e) depositing an isolation layer on said silicon substrate, said isolation layer burying said trench defined by said second liner insulating film;
(f) polishing and removing an unnecessary portion of said isolation layer by using said stopper layer as a polishing stopper; and
(g) etching said stopper layer. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of manufacturing a semiconductor device, comprising steps of:
-
(a) forming a polishing stopper layer on a surface of a silicon substrate, said stopper layer including a lower silicon oxide film and an upper silicon nitride film;
(b) etching said stopper layer and the silicon substrate by using a mask to form a trench in an isolation region defining active regions;
(c) side-etching the silicon oxide film of said stopper layer to retract side walls of the silicon oxide film;
(d) etching silicon to round a shoulder of the active region exposed by the retracted side wall;
(e) forming a liner insulating film on the surface of the silicon substrate, said liner insulating film being made of a silicon nitride film having a thickness of 2 to 8 nm;
(f) depositing an isolation layer on said silicon substrate, said isolation layer burying said trench defined by said liner insulating film;
(g) polishing and removing an unnecessary portion of said isolation layer by using said stopper layer as a polishing stopper; and
(h) etching said stopper layer. - View Dependent Claims (13, 14)
-
-
15. A semiconductor device comprising:
-
a silicon substrate with semiconductor elements;
an isolation trench formed in said silicon substrate for isolating active regions in said silicon substrate, said isolation trench having generally a trapezoidal cross sectional shape having a width gradually narrowing with a depth from a surface of said silicon substrate and having a gradually broadening upper portion, said isolation trench defining the active regions with rounded shoulders;
a liner insulating film formed in direct contact with a surface of said trench and made of a silicon nitride film having a thickness of 2 to 8 nm; and
an isolation region burying said trench defined by said liner insulating film. - View Dependent Claims (16, 17)
-
Specification