JPS6092634A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make the thickness of a residual film constant by holding a film containing no nitrogen in a nitride film to be etched as an etching marker, monitoring a N2 emission spectrum during plasma etching by the film containing no nitrogen and controlling the quantity of etching. CONSTITUTION:Insulating films in three-layer structure of a plasma CVD nitride film 1, an insulating film 2 containing no nitrogen and a plasma CVD nitride film 3 are formed on a lower layer wiring 4, and a through-hole pattern is formed by a photo-resist 5. The plasma CVD nitride film 3 is etched in an isotropic manner. The end point of etching of the plasma CVD nitride film 3 is detected and etching is stopped when etching reaches to the insulating film 2 containing no nitrogen by monitoring an emission spectrum from nitrogen, and a hole 6 is bored. The insulating film 2 containing no nitrogen and the plasma CVD nitride film 1 are etched in an an isotropic manner, thus forming a tapered through-hole 7, then exposing one part of a lower wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the technical field to which the invention pertains The present invention relates to a method for forming a glabellar insulating film in a multilayer wiring structure of a semiconductor device, and a method for forming the glabellar insulating film.

About how to form a through hole between the eyebrows.

(2) Description of the prior art Conventionally, when forming through holes in the interlayer insulating film of this type of semiconductor device, as the pattern becomes finer, it is necessary to
Processing using isotropic etching, a two-step process of etching and etching, and etching are performed. At this time, the method of forming the glabella insulating film and through-pole according to the prior art had the drawback that the amount of etching could not be detected and controlled sufficiently in the first step. (3) Detailed Description of the Invention The purpose of the invention is to solve the above drawbacks. In the nitride film used as the interlayer insulating film, a layer containing no nitrogen with a 1-Sand German f structure was added as a etch marker, and the nitrogen emission spectrum was monitored while being isotropically plasma-dried and etched. In one embodiment of the present invention, a through-hole shape with good reproducibility is provided by accurately etching up to the marker layer, reducing the remaining film thickness to the full thickness, and anisotropically etching the remaining film. , a plasma CVD nitride film as a first insulating film on the lower wiring formed on the substrate, and an insulating film as an etching marker that does not contain nitrogen as a second insulating film.

An interlayer insulating film having a three-layer structure of a plasma CVDM film as a third insulating film is completely formed, and the third insulating film is etched while monitoring the emission spectrum of nitrogen by plasma dry etching.
The plasma CVD nitride film as the insulating film is isotropically etched, and the second insulating film is an insulating film that does not contain Q chambers, and the first insulating film is anisotropically etched. A through hole is formed in the interlayer insulating film by etching.

(4) Detailed description of this invention Next, embodiments of the present invention will be described with reference to the drawings.

1 to 3 are fully blown cross-sectional views of the through-hole portion, lower layer wiring, and glabella insulating film in the process leading to through-hole formation, respectively.

2 steps, pue, ching using this invention? This is an example in which all through holes were formed. As shown in FIG. 1, on the lower wiring 4 are a plasma CVDM film 1, an insulating film (for example, 5 iOz) 2 that does not contain a stimulant, and a plasma CVD nitride film 3.
After forming the entire layered insulating film and forming a through hole pattern using photoresist 5, the plasma CVD nitride film 3 is isotropically etched by plasma dry etching as shown in FIG. At that time, by monitoring the emission spectrum of nitrogen, the insulating film 2TI that does not contain nitrogen is
The etching end point of the plasma CVD nitride film 3 can be detected at the point where the plasma CVD nitride film 3 is reached, and the etching can be completely stopped. Then, the plasma CVD nitride film 1 is etched by anisotropic etching, thereby forming a tapered through hole 7 and exposing a portion of the underlying wiring.

(5) Detailed Description of the Invention As explained above, the present invention comprises sandwiching a nitrogen-free film as an etching marker in a nitride film to be etched,
By monitoring the entire N2 emission spectrum during plasma etching, the amount of etching can be controlled and the thickness of the remaining film can be reduced.

[Brief explanation of drawings]

1-3 are cross-sectional views of an implementation of the present invention. 1... Plasma CVD nitride film, 2...
Insulating film that does not contain nitrogen (e.g. 5i (J2), 3...
...-plasma CVD nitride film, 4...lower wiring, 5...photoresist, 6...portion etched by monitoring nitrogen emission spectrum,
7. Mountain: Through hole formed by two-step etching according to the present invention.

Claims (1)

[Claims] A nitride film as a first insulating film, a nitrogen-free film as a second insulating film, an insulating film as a marking marker, and a nitride film as a third insulating film are formed on the lower wiring formed on the substrate.
a step of forming an interlayer insulating film having a layered structure; a step of isotropically etching the third insulating film while monitoring the emission spectrum of the chamber by plasma drying and etching; and a step of isotropically etching the third insulating film. and a step of anisotropically etching the first insulating film successively or separately.