Semiconductor device having a side wall film and method of producing the same

Claim 2

A semiconductor device comprising: a semiconductor substrate (21); an insulation film (24₁, 24₂, 24₃) formed on the semiconductor substrate; a film formed on the insulation film (22, 23) having a side wall; and a side wall film (22A) formed on the insulation film (22, 23) so as to surround the side wall of the film (24₁, 24₂, 24₃); the side wall film (22A) having a slope and satisfying a condition a > d where a is a width of a bottom surface of the side wall film (22A) which is in contact with the insulation film (22, 23) and d is a thickness of the film (24₁, 24₂, 24₃).

Claim 3

A semiconductor device as claimed in claim 1, wherein an angle of inclination of the slope of the film (24₁, 24₂, 24₃) in the vicinity of the insulation film is equal to or less than 60°.

Claim 4

A semiconductor device as claimed in claim 1, wherein the semiconductor device is a dynamic random access memory, and said film (24₁, 24₂, 24₃) is a gate film, and wherein the semiconductor device further comprises an interlayer insulation film (27) formed so as to cover the gate electrode (24₁, 24₂, 24₃), a memory cell capacitor (28 1A , 29 1A , 30₁) formed on the interlayer insulation film (27) being in contact with the semiconductor substrate (21) through a contact hole which penetrates the insulation film (23) and interlayer insulation film (27), another interlayer insulation film (31) formed so as to cover the memory cell capacitor (28 1A , 29 1A , 30₁); and a bit line (32₁) formed on the another interlayer insulation film (31).

Claim 5

A semiconductor device as claimed in claim 1, wherein said side wall film (22A) comprises silicon dioxide.

Claim 6

A semiconductor device as claimed in claim 1, wherein the slope of side wall film (22A) extends from a top surface of the film (24₁, 24₂, 24₃) to the insulation film (22, 23).

Claim 7

A semiconductor device as claimed in claim 1, wherein the side wall film (22A) is a film obtained by depositing a silicon dioxide film and patterning the deposited silicon dioxide film by anisotropic etching.

Claim 8

A process of producing the semiconductor device comprising the steps of: forming a first insulation film (22, 23) on the semiconductor substrate (21); forming a film (24₁, 24₂, 24₃) on the first insulation film; patterning the film (24₁, 24₂, 24₃); depositing a second insulation film of silicon dioxide on the entire surface of the substrate (21); and etching the second insulation film by anisotropic etching until a portion of the second insulation film on a flat surface of the first insulation film is completely removed, so that a side wall film (22A) of a remaining portion of the second insulation film is formed on the insulation film (22. 23) so as to surround the side wall of the film, the side wall film (22A) having a slope and satisfying a condition a > d where a is a width of a bottom surface of the side wall film (22A) which is in contact with the insulation film and d is a thickness of the film.

Claim 9

A process of producing the semiconductor device comprising the steps of: forming a first insulation film (22, 23) on the semiconductor substrate (21); forming a film (24₁, 24₂, 24₃) on the first insulation film; patterning the film (24₁, 24₂, 24₃); depositing a second insulation film of silicon dioxide on the entire surface of the substrate (21); and etching the second insulation film by anisotropic etching until a portion of the second insulation film on a flat surface of the first insulation film is completely removed, so that a side wall film (22A) of a remaining portion of the second insulation film is formed on the insulation film (22. 23) so as to surround the side wall of the film, the side wall film (22A) having a slope and satisfying a condition a > d where a is a width of a bottom surface of the side wall film (22A) which is in contact with the insulation film and d is a thickness of the film.

Claim 10

A method as claimed in claim 7, wherein the step of patterning the second insulation film is carried out by anisotropic etching.