JPS63310965A - Sputtering device - Google Patents

Abstract

PURPOSE:To easily deposit a thin film on a contact hole, etc., having a large aspect ratio by providing a directional controller for controlling the flying of sputtered particles almost in a single direction in a space between a sputtering target and a substrate. CONSTITUTION:A rare gas such as Ar is introduced into a vacuum vessel 3, a voltage is impressed on a cathode 4 to generate electric discharge, hence plasma is produced, the target 5 is sputtered, and a thin film is deposited on the substrate 7 opposed to the target 5. In the sputtering device, the direction controller 6 is arranged in the space between the target 5 and the substrate 7. The controller 6 is preferably constituted of by a cylindrical honeycomb aggregate having the specified unidirectional wall surface preferably in parallel with the groove on the substrate 7 or the side wall surface of a hole. The sputtered particles 61 having various emission angles are straightened in a single direction as the particles 62 by the controller 6, and made incident on the surface of the substrate 7. By this method, the thin film of a conductor, etc., is effectively deposited even on the bottom of the contact hole, etc., having a large aspect ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a sputtering apparatus for forming a thin film on the surface of a substrate having a fine structure.

(Prior Art) In the process of manufacturing integrated circuits such as semiconductors, there is a process of forming a thin film such as depositing a conductive thin film on the surface of a substrate for forming circuit wiring.

Sputtering is often used to form this thin film, but as the degree of integration of circuits increases, sputtering is often used at the bottom of deep holes such as deep grooves and contact holes with high aspect ratios (hereinafter referred to as aspect ratios). There is an increasing demand for film formation under harsh conditions, such as by depositing specific materials to form so-called "groove films" for wiring and the like.

In the sputtering method, a gas is introduced into a sputtering chamber and ionized by electric discharge, and a target made of the material to be deposited is bombarded with this ionized gas to eject molecules or atoms of the material to be deposited. This is a film forming method in which sputtered atoms are deposited on a substrate surface, and as is well known, sputtered atoms ejected from a target have an angular distribution approximately explained by Lambert's cosine law. (Refer to p. 25 of "Vacuum Deposition" published by Agne Co., Ltd.) (Problems to be solved by the invention) Figure 8 shows how a groove film is formed on a substrate having a contact hole with an aspect ratio of 1.0 using a conventional sputtering device. A cross-sectional view of the contact hole portion when formed is obtained by simulation. In the figure, 1 is a film deposited by sputtering, 10 is a groove film,
2 is a substrate.

As mentioned above, the sputtered atoms reaching the substrate from the target have various incident angles, so there is a shadow created by the hole step and a self-shadowing effect (this is discussed in the following references: Ito et al., VLSI thin film technology). ” Maruzen. and 1. A, Blech et al.
.

J. Appl., Phys., 54(6) 1983), so almost no film is deposited on the bottom of the hole.

(Objective of the Invention) The present invention solves this problem and provides a sputtering device that enables film formation on the bottom surface of a contact hole with a high aspect ratio, which has been considered impossible with the conventional technology. For the purpose of providing.

(Means for Solving the Problems) The present invention provides a sputtering apparatus for depositing a thin film on a substrate, in which a sputtering target is placed in a space between a sputter target and the substrate to cover the surface to be processed of the substrate. The above object has been achieved by a sputtering apparatus that is provided with a direction regulating device that regulates the direction of flight of sputtered particles flying towards a substantially single predetermined direction.

(Operation) Sputtered particles emitted from the target are restricted in flight, and only aligned sputtered particles flying in a substantially predetermined single direction will be incident on the substrate.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a front sectional view showing a schematic configuration of an embodiment of the sputtering apparatus of the present invention, in which 3 is a vacuum vessel, 4 is a cathode, 5 is a target, 6 is a direction regulating device that is a feature of the present invention, 7 is a substrate.

When a rare gas such as hair argon gas is introduced into the vacuum vessel 3 and a voltage is applied to the cathode 4, plasma is generated by discharge and the target 5 is sputtered.

The sputtered particles emitted from the target at this time are
As mentioned above, there are various emission angles according to the cosine law, but in this device, a beam is placed in the space between the target and the substrate, covering the surface to be processed of the substrate, and the main part is shown in FIG.
A direction regulating device 6 consisting of a honeycomb-like assembly of a large number of cylinders with both ends open is disposed.
When the sputtered particles pass through, the flight direction component is aligned in almost a single direction by allowing a certain angular error determined by the shape of the cylinder, that is, the ratio Q, /d of the length l of the cylinder and the diameter d of the cylinder. Only the sputtered particles 61 can fly toward the substrate surface. In this embodiment, the wall surface of the cylinder of the direction regulating device is made perpendicular to the substrate surface, considering that the walls of the contact holes provided on the surface to be processed of the substrate are almost perpendicular to the substrate surface. Therefore, only the sputtered particles 62 having a substantially vertical angle of incidence will be incident on the surface of the substrate 70.

Therefore, shadows and self-shadowing effects caused by grooves and hole steps such as contact holes are less likely to occur.
Films can be deposited extremely effectively even on the bottoms of contact holes and the like with high aspect ratios.

Now, a cathode with a diameter of 10 inches and A! Using a 1/1% Si target, the substrate was preheated to 400'C and then held at 200C to deposit films on the surface of the substrate having holes of various "aspect ratios." The direction regulating device is made of stainless steel with an inner diameter of 30 mm and a thickness of 1 mm.
, 55 cylinders with a length of 10.1 x 5.27 mm were placed in the second
As shown in the figure, welded honeycomb shapes are used.

FIG. 7 shows the experimental results. The vertical axis is "deposited film thickness at the bottom of the contact hole J/r deposited film thickness at the flat part"
, the horizontal axis indicates the "bottom coverage value", and the horizontal axis indicates the "depth of the contact hole"/"diameter of the bottom of the hole", that is, the "aspect ratio". The black circles are plots of each film deposited by the conventional apparatus without a direction regulating device, and the open circles are plots of each film deposited by the apparatus of the above embodiment.

In the conventional method, when the aspect ratio is 1.0, almost no film is deposited on the bottom of the contact hole, but when using the direction regulating device of the present invention, the bottom coverage is 7.
He has an excellent score of 0%.

The direction regulating device of the present invention is not limited to the above-mentioned cylindrical assembly, and can have various shapes and structures.

Fig. 3 shows a structure in which rectangular cylinders with both ends open are lined up and assembled in a honeycomb shape, Fig. 4 shows a structure in which multiple cylinders are arranged concentrically, and Fig. 5 shows a structure in which a plurality of cylinders are arranged concentrically. The device is shown in which a plurality of radial wall surfaces are added in an axial manner. Furthermore, FIG. 6 shows a direction regulating device that is simply constructed by arranging rectangular flat plates. In the direction regulating device shown in Figures 4 and 6,
Directional regulation is performed only in the direction parallel to the wall surface, but depending on the configuration of the semiconductor device, the type of groove, etc., a device with such a configuration may be sufficient or may produce special effects that cannot be obtained with other methods. This is something that can be done.

Note that in all of the above cases, direction regulation is performed in a direction perpendicular to the substrate surface, but depending on the structure of the semiconductor device,
It is sometimes effective to intentionally set the direction regulation diagonally.

Although the present invention is characterized by the installation of a direction regulating device, the direction regulating device has secondary effects other than those described above. For example, when the direction regulating device is made of a conductor and kept at ground potential as shown in Fig. 1, the main discharge plasma is confined between the cathode 4 and the direction regulating device, and damage to the substrate caused by the plasma can be greatly suppressed. I can do it.

Furthermore, a communication section 10 connects this direction regulating device to ground.
By connecting a discharge observation measuring instrument to the plasma, it becomes possible to observe the plasma during film formation and obtain the necessary data.

Since the main discharge is isolated from the substrate surface, there is also the advantage that, even when the substrate is transported, the stability of the discharge is not impaired by movement of the substrate.

In addition, by applying a bias voltage to this direction regulating device, it is possible to adjust the energy level of the ionized sputtered particles when they collide with the substrate surface to an appropriate value, and furthermore, the direction regulating device can be applied. By applying a bias voltage between the device and the substrate, the electric field on the upper surface of the substrate can be made uniform and at the same time, the biasing effect of the substrate can be enhanced.

As described above, the apparatus of the present invention is particularly effective in depositing conductor groove films for wiring, but it can also be expected to have great practical effects in forming insulating or semiconductor films.

(Effects of the Invention) As described above, the present invention enables thin film deposition with a simple structure in the production of thin films for wiring formation of integrated circuits such as semiconductors, especially in the production of groove films for contact holes with high aspect ratios. It has the effect of making it easier.

[Brief explanation of the drawing]

FIG. 1 is a schematic front sectional view of an embodiment of the present invention. FIG. 2 is a perspective view of a part of the direction regulating device. Third. 4.5. FIG. 6 is a perspective view of a direction regulating device according to another embodiment of the present invention. FIG. 7 is a graph of bottom coverage values versus aspect ratios for conventional and inventive devices. Figure 8 shows the aspect ratio of 1.0 obtained by conventional sputtering method.
A cross-sectional view of a simulation when a thin film is formed in a contact hole. 1...Thin film, 2...Substrate, 3...
...Vacuum container, 4...Cathode, 5...
・Target, 6...honeycomb direction regulating device,
7... Board. Patent applicant Kenji Murakami, agent of Nichiden Anelva Co., Ltd., patent attorney

Claims (4)

[Claims] (1) In a sputtering device that deposits a thin film on a substrate, in the space between the sputter target and the substrate,
A sputtering apparatus comprising a direction regulating device that covers a surface of the substrate to be processed and regulates the direction of flight of sputtered particles flying toward the surface of the substrate to substantially a single predetermined direction. (2) The sputtering apparatus according to item 1, wherein the thin film to be deposited is a conductor. (3) The sputtering apparatus according to item 1, wherein the direction regulating device is a honeycomb-like collection of cylinders having walls parallel to the single predetermined direction. (4) The sputtering apparatus according to item 1, wherein the single direction is parallel to the side wall surface of the groove or hole on the substrate surface.