JPS6260242A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve adhesion by a method wherein one or more compounds of specified elements are implanted into the interface between a polyimide film and a film thereunder for the blending of polyimide and PSG. CONSTITUTION:On the surface of a semiconductor substrate 1 with a prescribed semiconductor element built thereon is covered by a groundwork film that is a PSG film 2 of a required thickness. A lower wiring layer 3 of aluminum or the like is formed on the PSG film 2. A polyimide layer is formed by application on the entire surface, covering the lower wiring layer 3 and PSG film 2. Ion implantation follows, wherein one or more out silicon, nitrogen, carbon, oxygen, hydrogen, or their compounds are driven into the polyimide film 4. The implantation is so effected that the implanted ions may form an ion implanted layer 5 in the vicinity of the interface of the poplyimide film 4 and PSG film 2. In this way, the two films 2 and 4 are allowed to be physically blended with each other, which results in a stronger adhesion between the two films 2 and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device having a multilayer wiring structure, and particularly to a method for manufacturing a semiconductor device using a polyimide organic film as a glabellar insulating film.

[Conventional technology]

2. Description of the Related Art With the miniaturization and higher integration of semiconductor devices in recent years, the number of layers of wiring formed on a semiconductor substrate is increasing. Conventionally, in this type of multilayer wiring, CV was used as an interlayer insulating film.
Silicon oxide films and silicon nitride films formed by the D method are used, but these films have extremely poor surface flatness, causing defects such as step breaks in the upper wiring layer formed on top of them, making it difficult to miniaturize the wiring. It is an obstacle to doing so. For this reason, in the conventional manufacturing process of semiconductor devices, a process to planarize the surface of the interlayer insulating film is essential, and this flattening process complicates the manufacturing process of semiconductor devices. , and causes an increase in the number of manufacturing steps.

For this reason, attempts have recently been made to use a polyimide organic film as an interlayer insulating film, and the characteristics of this polyimide organic film provide sufficient flatness.

[Problem that the invention seeks to solve]

As mentioned above, when a polyimide organic film is used as an insulating film between the eyebrows, in semiconductor devices that use a PSG film as the underlying film, the adhesion between the polyimide organic film and the PSG film is poor, and the interlayer insulating film This may lead to peeling of the upper wiring layer,
Problems have arisen, such as reduced reliability as a semiconductor device. The detailed cause and mechanism of this adhesion are not clear, but according to the inventor's study, the degree of chemical or physical bonding between the two films at the interface is small, and the polyimide organic film This seems to be related to the fact that the film has a coefficient of thermal expansion one to two orders of magnitude larger than that of the PSG film, so it is easily subjected to thermal stress.

[Means for Solving the Problems] The method for manufacturing a semiconductor device of the present invention improves the adhesion between the polyimide organic film as the glabella insulating film and the PSG film as the base film, thereby producing a highly reliable semiconductor. In order to obtain a device, after forming a polyimide organic film, one or more of silicon, nitrogen, carbon, oxygen, hydrogen, and compounds of these elements are ionized at the interface between the polyimide organic film and the underlying film. The process includes a step of mixing polyimide and PSG at the interface between the two to improve their adhesion.

〔Example〕

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

1 to 4 are cross-sectional views showing an embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 1, a PSG film 2 as a base film is formed to a required thickness on the surface of a semiconductor substrate 1 on which a predetermined semiconductor element is formed, and then a metal film such as aluminum is formed on this film. A lower wiring layer 3 is formed.

Next, as shown in FIG. 2, a polyimide organic material is applied over the entire surface by a spin code method, and
A polyimide organic film 4 covering the SG film 2 is formed. The film thickness of this polyimide organic film 4 is determined to be a thickness that corresponds to the underlying structure such as the thickness and line width of the lower wiring layer 3, and the flatness and electrical characteristics (for example, interlayer capacitance). Then, it is formed to have a thickness of 1 μm.

Then, as shown in FIG. 3, one or more of silicon, nitrogen, carbon, oxygen, hydrogen, and compounds of these elements are introduced into the polyimide organic film 4 by ion implantation. At this time, the acceleration voltage during ion implantation is controlled so that the implanted material is distributed near the interface between the polyimide organic film 4 and the PSG film 2 to form the ion implantation layer 5. For example, about 250 KeV for silicon and about 15 KeV for nitrogen.
0KeV, about 200KeV for carbon, about 150 for oxygen
KeV and hydrogen are set to about 30 KeV, respectively.

As shown in FIG. 4, when forming a contact hole 7 for connection to the lower wiring layer 3, a mask film 6 having a laminated structure of a silicon oxide film and a photoresist film is formed, and CF, A silicon oxide film is opened in a gas plasma mainly composed of , and a polyimide organic film 4 is opened in an oxygen gas plasma. In addition, by forming the upper wiring layer 8 of aluminum or the like as indicated by the chain line in the figure, the upper wiring layer 8 and the lower wiring layer 2 can be connected through the contact hole 7.

Therefore, in the multilayer wiring structure manufactured in this way, the polyimide organic film 4 as the glabella insulating film has the ion-implanted layer 5 of the various element types described above formed at the interface with the PSG film 2 as the base film. Therefore, both membranes 2.
4 physically mix with each other at the interface, improving the adhesion between the two. This prevents the polyimide organic film 4 from being easily peeled off from the PSG film 2.
The reliability of the multilayer wiring structure, that is, the semiconductor device can be improved. Of course, due to the characteristics of the polyimide organic film, its surface can be extremely flat, and the upper wiring layer 8
Needless to say, it is possible to achieve miniaturization of wiring by preventing step breaks and the like.

In the embodiment described above, the ion implantation layer 5 is also formed at the interface between the lower wiring layer 3 and the polyimide organic film 4, so that the adhesion between the two can be improved.

〔Effect of the invention〕

As explained below, in the present invention, when manufacturing a multilayer interconnection structure having a polyimide organic film as an interlayer insulating film and a PSG film as an underlying film, silicon, nitrogen, and carbon are added after forming the polyimide organic film. , oxygen, hydrogen, and compounds of these elements are ion-implanted into the interface between the polyimide organic film and the underlying film. Adhesion can be improved, and the upper wiring layer can be made finer by utilizing the surface flatness, which is an advantage of polyimide organic films, and peeling of the polyimide organic film can be prevented, resulting in high integration and reliability. Semiconductor devices can be manufactured.

[Brief explanation of drawings]

1 to 4 are cross-sectional views showing the manufacturing method of the present invention in the order of steps. 1... Semiconductor substrate, 2... Base film (PSG film), 3
... Lower wiring layer, 4... Polyimide organic film, 5...
- Ion implantation layer, 6... mask, 7... contact hole, 8... upper wiring layer. Agent Patent Attorney Susumu Uchihara,,',',',M
Pay (・I5; 7.J -7'rJ'r'E/ \--/' -to 达 Sorry for the loss)

Claims (1)

[Claims] 1. When manufacturing a semiconductor device with a multilayer wiring structure having a polyimide organic film as an interlayer insulating film and a PSG film as a base film, after forming the polyimide organic film, silicon, nitrogen, A step of ion-implanting one or more of carbon, oxygen, hydrogen, and compounds of these elements into the interface between the polyimide organic film and the base film, and mixing the polyimide and PSG at the interface between the two. A method for manufacturing a semiconductor device, characterized in that: 2. A patent in which a PSG film is formed on a base film, a polyimide organic film is formed on this lower wiring layer, and then ions are implanted from the surface of the polyimide organic film at a required acceleration voltage. A method for manufacturing a semiconductor device according to claim 1.