JPH07114239B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device in which an interlayer insulating film of a multilayer wiring is planarized by using an organosiloxane polymer.

[Conventional technology]

In recent years, the wiring of semiconductor devices has been miniaturized and multilayered, and thus it has become important to flatten the wiring interlayer insulating film. As one of the flattening methods, there is a method using an organic siloxane polymer. Organosiloxane polymers are ladder-type organosiloxane polymers _{R 1, R 2: -CH 3} , C 6 H 5, C 2 H 2 , etc. _{R 3: -CH 3, C 2} H 5, H , etc., silicone Or the synthesized of these silanols _{R 1, R 2: CH 3} , C 2 H 5, C 6 H 5 , _{etc., R 3: H, CH 3} , C 2 H 5 or the like Si-O bonds, such as a main chain, has a R or OR-terminated Refers to all polymers.

When an organic siloxane-based polymer is used for the interlayer insulating film,
As shown in FIG. 6, an inorganic insulating film 64 is formed on the wiring 63, then an organic siloxane polymer solution is applied, and heat treatment is performed to bond them to form a second wiring layer 66 thereon.
As shown in FIG. 7, a second wiring layer is formed with an inorganic insulating film 76 interposed therebetween.
Form 77. At this time, the organic siloxane polymer solution 6
The organic components such as methyl groups and phenyl groups present on the surface of 5,75 prevent the bonding with the metal 66 and the inorganic insulating film 76 in the upper layer and deteriorate the adhesion. The method of dissociating the organic component of the organic siloxane-based polymer by performing O ₂ plasma treatment is performed.

[Problems to be Solved by the Invention]

In the conventional method of manufacturing a semiconductor device described above, since the organic component of the organic siloxane-based polymer is dissociated by O ₂ plasma, the organic component in the film is uniformly dissociated as shown in FIG. There was a drawback that cracks and cracks occurred. Further, when O ₂ plasma is used in a later step, there is a drawback that the organic component in the film is further dissociated and the film quality is deteriorated.

[Means for Solving the Problems]

A method of manufacturing a semiconductor device according to the present invention includes a step of forming a first metal wiring layer on a semiconductor substrate via an insulating film, and a step of forming a first inorganic insulating film on the first metal wiring layer. And a step of applying an organic siloxane-based polymer solution on the first inorganic insulating film, a step of exposing the organic siloxane-based polymer solution to O ₂ plasma at a pressure of 1 Torr or less to dissociate an organic component near the surface of the organic siloxane-based polymer, and a heat treatment. And the step of forming an organic siloxane-based polymer bond and the step of forming a second wiring metal layer on the organic siloxane-based polymer directly or via the second inorganic insulating film.

The present invention applies an organic siloxane-based polymer solution, performs O ₂ plasma treatment at a pressure of 1 Torr or less to dissociate organic components in the vicinity of the surface before the crosslinking reaction proceeds, and then heat-treats to crosslink the polymer. As a result, the adhesion with the upper layer film can be improved without degrading the film quality.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

1A to 1C are process sectional views showing an embodiment of the present invention. First, as shown in FIG. 1A, an Al wiring 13 is formed on an insulating film 12 on a semiconductor substrate 11, and plasma CV is used.
An oxide film 14 (hereinafter referred to as a plasma oxide film) is grown by the D method, and an organosiloxane polymer solution is applied. Next, the substrate 11 is placed in a parallel plate type plasma device as shown in FIG.
And plasma is generated in an atmosphere of 0.5 TorrO ₂ for 10 minutes. Next, heat treatment is performed at 400 ° C. for 30 minutes in an N ₂ atmosphere to bond the films. At this time, near the surface of the membrane,
As shown in FIG. 1 (B), a layer 16 in which the organic component is dissociated is formed. Next, after forming a through hole, an Al wiring 17 is formed as shown in FIG. 1 (C).

FIG. 3 shows the carbon concentration in the film of the organosiloxane polymer formed by this method. The carbon concentration from the surface to about 1500 Å is greatly reduced, but at deeper places it is almost the same as without treatment. Further, even after the O ₂ plasma ashing, the film was hardly damaged at a location deeper than about 1500 Å, showing that a film having high O ₂ plasma resistance was formed on the surface. This is different from the case where the plasma treatment is performed after firing (Fig. 4), because the organic component is dissociated at the time when the cross-linking reaction of the polymer has not yet proceeded, so that the dissociated portion of the organic component is also siloxane-bonded at the time of subsequent firing. It is considered that a dense film was formed.

FIG. 5 is a vertical sectional view of another embodiment of the present invention. Here, an organosiloxane polymer is applied and plasma treatment is performed for 1 minute, as in the case of one example. Next, heat treatment is performed to grow a plasma oxide film 57, and after forming a through hole, an Al wiring 58 is formed. In this embodiment, since the upper layer plasma oxide film 57 is present, the O ₂ plasma resistance of the organic siloxane-based polymer does not need to be so large, so that the adhesion with the upper layer plasma oxide film is sufficiently improved for about 1 minute. Therefore, the plasma processing time can be shortened.

〔The invention's effect〕

As described above, in the present invention, since the organic siloxane polymer dissociates the organic components near the surface in a non-crosslinked state, heat treatment is performed to bond the films, so that a dense film close to an inorganic film is formed on the surface. This makes it possible to improve the adhesion to the upper layer film without deteriorating the film quality, and prevent damage due to O ₂ plasma in the subsequent step. As a result, a wiring interlayer film having good flatness and high reliability can be formed, and a highly reliable semiconductor device can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1C are process cross-sectional views for explaining an embodiment of the present invention, and FIG. 2 shows a plasma processing apparatus used in the embodiment of the present invention. A sectional view, FIG. 3 is a graph showing a carbon concentration in an organic siloxane-based polymer formed according to one embodiment of the present invention, and FIG. 4 is a graph showing a carbon concentration in an organo-siloxane-based polymer formed according to a conventional example. FIG. 5 is a vertical sectional view showing another embodiment of the present invention, and FIGS. 6 and 7 are vertical sectional views showing a conventional example. 11,51,61,71 …… Semiconductor substrate, 12,52,62,72 …… Insulating film,
13,17,53,58,63,66,73,77 …… Al wiring, 14,54,57,64,74,
76 ... Plasma oxide film, 15,55,65,75 ... Organosiloxane polymer, 16,56 ... Dissociated layer of organic components, 67 ...
… Crack, 78 …… Peeling.

Claims (1)

[Claims] 1. A step of forming a first metal wiring layer on a semiconductor substrate through an insulating film, a step of forming a first inorganic insulating film on the first metal wiring layer, and a step of forming the first inorganic insulating film. of a step of applying the organic siloxane polymer solution on the inorganic insulating film, a step of dissociating an organic component in the vicinity of the surface of the organic siloxane polymer exposed to O ₂ plasma pressures below 1 Torr, organosiloxane subsequently subjected to a heat treatment And a step of forming a second metal wiring on the organic siloxane-based polymer directly or via a second inorganic insulating film.