JPS5948939A - Method and apparatus for forming film - Google Patents

Abstract

PURPOSE:To obtain the excellent film without depending upon the shape of a substrate by irradiating excitation energy to a vapor current when the vapor current is made to hit against the substrate and an evaporated substance is attached on the film. CONSTITUTION:The substrates 20 are fitted to a holder 11, an Al alloy 21 is entered in a vessel 12, and a chamber 10 is evacuated to a high degree through a valve 13. The alloy 21 is heated and melted to manufacture the vapor current while an electron accelerator B is worked in a flying process of the current to discharge electron rays, electrons are made collide with vapor particles, and the current is changed into a vapor current having high energy as a whole. When the vapor current having high energy reaches the substrate 20, it moves on the surface at mobility larger than the normal rate, and a uniform crystalline nucleus is generated, and grows in the equal directions without depending upon the shape of the substrate. Accordingly, the excellent film 24 is also obtained in the vertical stepped-difference section of the connecting window of an SiO2 film 23 on a wafer 22.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film forming method and a film forming apparatus, and includes, for example, irradiating excitation energy such as an electron beam to an evaporated substance to be deposited when forming a wiring film, etc. in the manufacture of semiconductor elements. It is an object of the present invention to provide a film forming method and a film forming apparatus that allow the film to be deposited extremely smoothly, that is, even on areas where there are steps in the deposited film portion, the film can be deposited neatly.

For example, with the miniaturization of semiconductor elements, wiring film coverage has become a problem, particularly in portions with stepped shapes. That is, the wiring film forming step in the semiconductor device manufacturing process is carried out by depositing a material such as aluminum or an aluminum alloy onto a substrate by vacuum evaporation or sputtering. For example, a substrate 3 is placed in a substrate holder 2 of a vacuum evaporation apparatus 1 as shown in FIG.
The particles are evaporated using an evaporation source material 4 such as aluminum and deposited on the surface of the substrate 3 to form a film.

However, when the substrate 3 on which the film is to be formed has a stepped shape, as shown in FIG. In the case where the oxide film 6 is structured as shown in FIG. The thickness d2 of the wiring film 72 becomes extremely thin, and cracks occur at the boundary between the part of the wiring film 73 formed in the contact hole and the part of the wiring film 72 formed on the slope. There is a tendency for the wiring film to be easily disconnected, which deteriorates the reliability and manufacturing yield of the device. Therefore, in order to increase the coverage rate of the wiring film, methods have been proposed such as reducing the taper angle θ of the inclined part (11) or changing the incident angle of the coating material, but these methods are still not fully effective. No means have yet been developed.Particularly, as the density of semiconductor devices increases, portions with stepped portions such as contact holes are forced to have vertical walls, making it difficult to form a wiring film well.

The present inventor believes that the occurrence of the above problem is due to the fact that the film growth rate in the horizontal direction is extremely slow relative to the film growth rate in the vertical direction with respect to the substrate of the film to be deposited, and that It was determined that this was due to the fact that fewer crystal nuclei were generated at the bottom corner of the step, and as a result of further research, it was discovered that the vapor flow of the material being deposited on the substrate reached the substrate. If the vapor flow is irradiated with excitation energy such as an electron beam in the process before film deposition, and the particles in the vapor flow are brought into an excited state with a high energy state, evaporation with such a high energy state can be prevented. When the substance reaches the substrate 714, the generation of crystal nuclei is uniform regardless of the shape of the substrate, and in the film growth process after nucleation, the film growth rate in the horizontal direction with respect to the substrate increases. They discovered this and accomplished the present invention based on this principle.

Embodiments of the film forming method and film forming apparatus according to the present invention will be described below, taking a vacuum evaporation method as an example.

FIG. 3 is a schematic explanatory diagram of the film forming apparatus according to the present invention, in which 10 is a chamber of the vacuum evaporation apparatus A, 11 is a substrate holder, 12 is a container containing a deposition source material, and 13 is a vacuum valve. These configurations are the same as those of conventional vacuum evaporation equipment.

14 is a filament, 15 is a filament heating power source, 1
6 is an accelerating electrode, 17 is an accelerating voltage power source, and these constitute an electron accelerator B.
A vacuum evaporation apparatus is provided so that the electron beam emitted by the evaporation source material collides with the evaporated material from the evaporation source material. still,
The electron beam emitted from the electron accelerator is oriented so as not to collide with the substrate attached to the substrate holder.

In such an apparatus, a substrate 20 is placed on a substrate hotadder 11.
Also, put a wiring film constituent material 21 such as an aluminum alloy into the container 12, and after evacuating the inside of the chamber 1o to a high vacuum via the vacuum valve 13, heat the container 12 to prepare the wiring film material 21. The constituent material 21 is heated and melted to create a vapor flow as shown by the dotted line in FIG. Several tens of eV, for example 30e
The electrons with an energy of V are bombarded to cause the evaporated particles to be in the ionized p1 excited state, converting them into a vapor stream with an overall high energy.

In this way, a high-energy vapor flow is applied to the substrate 20.
When it reaches , it moves on the substrate surface with a higher mobility than usual, uniform crystal nuclei are generated on the substrate surface, and the film growth rate in the direction horizontal to the substrate is also high, so the film grows regardless of the shape of the substrate. For example, as shown in FIG. 4, the substrate 2o has a stepped portion with vertical walls, such as the one in which an oxide film 23 is formed on a silicon wafer 22 and a contact hole is formed. A clean film 24 can be formed even if there is some scratches.

As mentioned above, the film forming method according to the present invention irradiates the vapor flow with excitation energy when depositing the evaporated substance onto the substrate by directing the vapor flow to the substrate. The film can be formed neatly, and wiring films can be formed reliably even on devices with contact poles during the manufacturing of semiconductor devices, resulting in highly reliable devices with high yields. Since the film forming device is equipped with an excitation energy irradiation device for the substance constituting the vapor flow, it has the advantage that a clean film can be formed on the substrate with a simple device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional vacuum evaporation apparatus, FIG. 2 is an explanatory diagram of a film formed on a substrate by the evaporation method, FIG. 3 is an explanatory diagram of one embodiment of the film forming apparatus according to the present invention, and FIG. FIG. 2 is an explanatory diagram showing the implementation of the film forming method of the present invention. A... Vacuum deposition device, B... Electron accelerator, 2o... Substrate, 24... Film. Patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Claims] ■ When applying a vapor flow to a substrate to deposit an evaporated substance into a film,
A film formation method characterized by irradiating excitation energy to a vapor flow. (2) A film forming apparatus characterized in that an apparatus for forming a film by applying a vapor flow to a substrate is provided with an excitation energy irradiation device for a substance constituting the vapor flow.