JPS59121923A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve coverage at the step parts of a semiconductor device by performing heat treatment without deteriorating the characteristic of a semiconductor element by a method wherein a metal wiring layer of Al, etc., is formed, an insulating film adhered thereon is formed to the necessary pattern of the metal wiring in this condition, and laser annealing is performed from the upper side. CONSTITUTION:An insulating layer, an SiO2 layer 3 for example, having a contact hole 2 is formed on a silicon substrate 1, and when an Al layer 4 is formed extending over the whole surface, step parts 5 are generated. Then an insulating film 6 is adhered on the Al layer 4, and patterning is performed. Laser scanning is performed extending over the whole surface according to CO2 laser to perform heat treatment. When the laser beam is irradiated, the temperature of the Al layer 4 is risen only through the patterned insulating film 6, the step parts 5 also heated, and because the step parts are molten a little, step coverage is improved. At the regions not formed with the pattern of the insulating film 6 because the Al layer 4 is left in the exposed condition, even when laser is irradiated thereto, laser is reflected wholly, a semiconductor element formed in the silicon substance 1 is not heated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and in particular to a semiconductor device in which the step coverage range of a wiring metal layer such as aluminum is improved using a heat treatment method such as laser annealing. The present invention relates to a method for manufacturing a device.

(2) Background of the technology In recent years, LSI technology has developed significantly. For example, along with advances in microfabrication technology, MO3 type semiconductor devices, which occupy a small area per gate and are easy to process, are suitable for LSI integration and have made a major contribution to this development.

When increasing the density of such MO3 type semiconductor devices, for example, as the dimensions approach the wavelength of the exposure light source used in the photoresist process, electron beams or X
Various methods for forming and transferring patterns of integrated circuits using lines and the like have been developed.

For this reason, there is a demand for the development of various miniaturization technologies in processing technology.

(3) Prior art and problems When forming an insulating layer on a semiconductor substrate, making contact holes in this insulating layer, and wiring aluminum wiring on the surface,
The application of laser annealing is being considered in order to improve the step coverage in the stepped portion of the aluminum wiring near the contact hole and to advance miniaturization technology.

In such laser annealing, since the absorption rate is low even if the laser is irradiated directly onto aluminum, after the vacuuming of the aluminum wiring is completed, an insulating film such as PSG (phosphosilicate glass) is formed on the entire surface of the aluminum wiring. The stencil coverage method is improved by irradiating a laser to slightly melt the aluminum wiring layer and making the stepped portion of the aluminum wiring loose in the vicinity of the contact hole.

However, since conventional laser irradiation is performed from above the PSG layer formed on the entire surface, parts other than the aluminum wiring layer are also heated, which causes damage to the diffusion depth, etc. of the semiconductor element formed on the semiconductor substrate. This has the disadvantage that it affects the semiconductor device and deteriorates the characteristics of the semiconductor element.

Furthermore, if the insulating film formed over the entire surface is formed thick in advance in order to prevent heating by laser annealing from affecting the semiconductor element, it will not be suitable for miniaturization of semiconductor devices.

4. Purpose of the Invention In view of the above-mentioned conventional drawbacks, the purpose of the present invention is to form a metal wiring layer such as pattern A on the entire surface, form an insulating film thereon in a desired metal wiring pattern, and then irradiate it with a laser beam from above. To provide a method for manufacturing a semiconductor device, which selectively heats only a wiring pattern portion formed of an insulating film by annealing, and improves the coverage range at a stepped portion without deteriorating the characteristics of a semiconductor element. It is in.

(5) Structure of the Invention According to the present invention, the purpose is to form a wiring metal layer on the surface of a semiconductor substrate having a step, form an insulating film pattern on the metal layer, and then perform laser irradiation. This is achieved by providing a method for manufacturing a semiconductor device, characterized in that the step coverage range of the metal layer is improved.

(6) Embodiment of the Invention Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 (al to (C1) are schematic sectional views showing the manufacturing process of the present invention.

An insulating layer, such as a SiO2 layer 3, having a contact hole 2 is formed on a silicon substrate 1 by predetermined patterning.
1! m thickness and further A72 layer 4 to perform A7+ wiring.
When formed to a thickness of approximately 1 μm over the entire surface, the A1 layer 4 has a stepped portion 5 near the contact hole 2. ((a) in the same figure) Next, an insulating film 6 such as a PSG film or SiO
2,000 layers are deposited to a zero thickness and patterned to have the same pattern as a predetermined aluminum wiring pattern to be formed. ((b) in the same figure) Furthermore, scanning is performed over the entire surface using, for example, a CO2 laser, that is, a heat treatment of laser annealing is performed. (Same figure (
C)) Note that in FIGS. 1A to 1C, the semiconductor elements formed on the silicon substrate 1 are not shown. During laser beam irradiation, the temperature of the A4 layer 4 is increased only through the patterned insulating film 6, and the step portion 5 of the /1 layer 4 is also heated and slightly melted, so that the step coverage is as shown in Figure 1 ( This will be improved as shown in C). Furthermore, in areas where the pattern of the insulating film 6 is not formed, such as areas other than the stepped portions, the A1 layer 4 remains exposed, so even if the laser is irradiated, it will be reflected entirely.
The semiconductor element formed on the silicon substrate 1 is not heated.

Next, the AN layer 4 is selectively dry-etched using boron trichloride (BCC20, etc.) using the insulating film 6 as a mask, leaving only the aluminum wiring pattern. Then, a protective cover PSG is formed over the entire surface. .

(7) Effects of the Invention As described above, if the present invention is used, the AN layer is formed over the entire surface and the insulating film is provided only in a predetermined area and heat treatment such as laser annealing is performed, so that the heat This has the effect of preventing damage to the diffusion depth, etc. of the semiconductor element because it is less likely to reach the substrate.

Further, when the present invention is used, the etching selectivity between the A4 layer and the insulating film is increased, so that the insulating film and the resist for patterning the insulating film can be made thinner, which is suitable for miniaturization.

[Brief explanation of drawings]

FIG. 1 is a schematic process cross-sectional view illustrating a method of manufacturing a semiconductor device using the present invention. 1... Silicon substrate 2... Contact hole 3... Insulating film 4... Aluminum layer 5... Step portion 6... Insulating film patent applicant Fujitsu Limited

Claims (1)

[Claims] (1) Forming a wiring metal layer on the surface of a semiconductor substrate having a step, forming an insulating film pattern on the metal layer, and then irradiating the metal layer with a laser to improve step coverage of the metal layer. A method for manufacturing a semiconductor device, characterized by: