JPS62211375A - Sputtering device - Google Patents

Abstract

PURPOSE:To form a thin film having an excellent film thickness distribution condition on a substrate to be treated by integrally arraying plural magnets, which are disposed on the side opposite from the substrate relative to a target, to a specific heart-shaped closed curve shape and rotating the same eccentrically around the center of the target at the time of making a magnetron sputtering treatment. CONSTITUTION:The substrate 5 to be treated and the target 3 are disposed in a vacuum vessel 6 of a magnetron sputtering device. A steel base 2 attached with the many magnets 1 on the outside of the target 3 is made rotatable eccentrically in the position where the center thereof is off the center of the target 3. The many magnets 1 are arrayed on the heart-shaped closed curve in such a manner that the same magnetic poles face the inside. The closed curve exists in the region enclosed by the curve expressed by the equation [1] where the distance from the origin O to the closed curve is designated as (r), the distance between the central point A of the closed curve and the recessed point B thereof as l, the coordinate at the central point A of the closed curve as X=-a, the coordinate at the recessed point B as X=l-a and the angle between (r) and the X-axis as theta in the X-Y coordinates with the origin O at the center of the target as well as the circle of the radius l around the A.

Description

[Detailed Description of the Invention] [Summary] In order to improve the film thickness distribution of a film deposited by a magnetron sputtering device, an optimal arrangement of magnets is selected from a shape intermediate between a conventional heart-shaped closed curve and a circle. Bring up the device.

[Industrial application field]

The present invention relates to a sputtering apparatus with improved film thickness distribution.

In the manufacture of semiconductor devices, sputtering equipment is widely used to deposit conductive layers such as aluminum, high melting point metals such as molybdenum and tungsten, or silicides thereof onto substrates.

A magnetron sputtering device is a device in which a magnet is placed on the back side of the target to increase the plasma density on the target and increase the sputtering speed.In order to obtain an even film thickness distribution on the substrate, In order to improve the efficiency of target use, various arrangements of magnets have been devised.

[Conventional technology]

FIG. 2 is a side sectional view illustrating the magnetron sputtering apparatus.

In the figure, 1 is a magnet and 2 is a stand made of stainless steel.
The table 2 is placed on the target 3 and can be rotated eccentrically from the center of the target 3.

A target 3 made of a deposition material is attached to a banking plate 4 made of copper.

The banking plate 4 is electrically insulated and placed in the vacuum container 6 in a vacuum-tight manner so that the target 3 is on the inside.
can be attached to.

The substrate 5 to be processed is held at the same potential as the vacuum container 6 and facing the target 3 .

The vacuum container 6 is exhausted from the exhaust lower, and argon (Ar) is introduced from the gas inlet 8 to maintain a predetermined pressure.

The substrate to be processed 5, that is, the vacuum container 6, is grounded, and the banking plate 4 is powered by a direct current (DC) power source 9 at -350 to
-500V is applied.

The power of the DC power supply 9 depends on the size of the device, but is 1 to 20K.
It is W.

With this configuration, the meter is ionized by the power applied to the target 3 and the substrate 5 to be processed, and argon ions (Ar
”) is ejected from the negatively biased target material to form a film on the substrate 5 to be processed.

FIGS. 3(1), 3(2), and 3(3) are a plan view showing the arrangement of magnets in a conventional magnetron sputtering device, and a cross-sectional view of a target showing the film thickness distribution and erosion, respectively.

FIG. 3(1) is a plan view showing the heart-shaped closed curve arrangement of magnets proposed earlier by the present inventor.

In the figure, in the xy coordinates with the center of the target 3 as the origin O, the distance from the origin O to the heart-shaped closed curve is r,
The distance between the center point A of the heart-shaped closed curve and its concavity B point is β, the coordinates of the center A point of the heart-shaped closed curve are x=-a, and the coordinates of the concavity point B of the heart-shaped closed curve are x=l1-a , the angle that r makes with the X axis is θ, then the heart-shaped closed curve is r=l−a+2a |θ|/π, (−π≦θ≦π).

It can be expressed as

The film thickness distribution and target erosion when sputtering is performed without rotating the magnet around the origin 0 are shown below.

In FIG. 3(2), the film thickness distribution produces a concave portion in the center of the substrate.

In Figure 3 (3), the target erosion is 2
The area between the two concentric circles becomes approximately flat.

In this example, target erosion is good, but film thickness distribution is poor.

Figures 4 (1), (2), and (3) are a plan view showing the arrangement of magnets in another conventional magnetron sputtering device, and a cross-sectional view of the target showing the film thickness distribution and erosion, respectively. It is.

FIG. 4(1) is a plan view showing a generally used eccentric circular arrangement of magnets.

In the figure, in the xy coordinates with the center of the target 3 as the origin O, the magnet is centered at the coordinate x=-aOA point,
arranged on a circumference of radius l (the figure shows an integrated magnet).

The film thickness distribution and target erosion when sputtering is performed without rotating the magnet around the origin 0 are shown below.

In FIG. 4(2), the film thickness distribution tends to produce a convex portion at the center of the substrate.

FIG. 4(3-1) shows the case where the target is small, and the target's erosion produces two valleys in the area between the two concentric circles.

FIG. 4 (3-2) shows a case where the target is large and the eccentricity (a) is large, and the two valleys are further emphasized.

In this example, both target erosion and film thickness distribution are poor.

[Problem that the invention seeks to solve]

With the conventional magnet arrangement, the thickness distribution of the deposited film is not good.

[Means for solving problems]

The above problem can be solved by arranging a magnet on the opposite side of the target from the substrate to be processed, and fixing a plurality of magnets in a line on a heart-shaped closed curve with the same magnetic poles facing inward. The heart-shaped closed curve is configured to be able to rotate around the center of the target, and the distance between the origin O and the heart-shaped closed curve is r in the xy coordinates with the center of the target as the origin 0.

The distance between the center point A of the heart-shaped closed curve and its depression point B is β, the coordinates of the four center points of the heart-shaped closed curve are x=-a, and the coordinates of the depression point B of the heart-shaped closed curve are x=/-a, r Let θ be the angle that it makes with the X axis, then r-1! -a+,! a 1θ1
/π.

(−π≦θ≦π).

This is achieved by the sputtering apparatus according to the present invention, which exists within a region surrounded by a curve expressed by , and a circle having a radius l centered at point A.

Furthermore, the same effect can be obtained when a plurality of the magnets are successively integrated.

[Effect]

The present invention focuses on the fact that the tendency of film thickness distribution curves in the conventional heart-shaped closed curve arrangement and the eccentric circle arrangement of magnets tends to be contradictory, and discovers that the optimum value is in the intermediate region between these, and thereby achieves a uniform This is to obtain a film with a certain thickness.

〔Example〕

FIGS. 1 (1), (2), and (3) are a plan view showing the arrangement of magnets in a magnetron sputtering apparatus according to the present invention, and a cross-sectional view of a target showing the film thickness distribution and erosion, respectively.

In FIG. 1 (1), the solid line is a heart-shaped closed curve showing the arrangement of magnets according to the present invention, the chain line is a heart-shaped closed curve according to the conventional example shown in FIG. 3, and the dotted line is a plan view showing an eccentric circle according to the conventional example shown in FIG. It is.

The heart-shaped closed curve according to the present invention is defined as follows: In the xy coordinates with the center of the target as the origin O, the distance from the origin O to the heart-shaped closed curve is r, the distance between the center point A of the heart-shaped closed curve and its depression point B is l, The coordinates of the center point A of the heart-shaped closed curve are x=-a, and the coordinates of the center point A of the heart-shaped closed curve are (
If the coordinates of point B of the indentation are X=β−a, and the angle that r makes with the X axis is θ, then r=Il−a+2a |θ|/π, (−π≦θ≦π).

It exists in a region surrounded by a curve (chain 'fIA) expressed by , and a circle (dotted line) with radius l centered at point A.

The film thickness distribution and target erosion when sputtering is performed without rotating the magnet around the origin O are shown below.

In FIG. 1(2), the film thickness distribution is approximately uniform within the substrate except for the peripheral portion.

In Figure 1 (3), the target erosion is 2
This produces only two valleys in the area between the two concentric circles.

〔Effect of the invention〕

As described above in detail, the sputtering apparatus having the magnet arrangement according to the present invention can form a film with a uniform film thickness distribution.

[Brief explanation of drawings]

FIGS. 1 (1), (2), and (3) are respectively a plan view showing the arrangement of magnets in the magnetron sputtering apparatus according to the present invention, a cross-sectional view of the target showing the film thickness distribution of the deposited film, and erosion, and FIG. The figure is a side sectional view illustrating a magnetron sputtering device, and FIGS. 3 (1), (2), and (3) are plan views showing the arrangement of magnets in a conventional magnetron sputtering device and the film thickness distribution of the deposited film, respectively. and a cross-sectional view of a target showing erosion. Figures 4 (1), (2), and (3) are plate views showing the arrangement of magnets in magnetron sputtering equipment according to other conventional examples, and the film thickness distribution of the deposited film, respectively. FIG. 3 is a cross-sectional view of a target showing erosion. In the figure, 1 is a magnet, 2 is a stand, 3 is a target, 4 is a puffing plate, 5 is a substrate to be processed, 6 is a vacuum container, 7 is an exhaust port, 8 is a gas inlet, 9 is a power supply Mag 3 Throns 1 ~ Yuryo! In this order: 2 drawings of moving figures - Antibacterial paper -

Claims (2)

[Claims] (1) A magnet is placed on the opposite side of the target from the substrate to be processed, and a plurality of magnets are arranged and fixed on a heart-shaped closed curve with the same magnetic poles facing inward, and the magnets are placed in the center of the target. The heart-shaped closed curve is configured so that it can rotate around the center of the heart-shaped closed curve, and in the xy coordinates with the center of the target as the origin 0, the distance from the origin 0 to the heart-shaped closed curve is r, and the center point A of the heart-shaped closed curve and its indentation B If the distance to the point is l, the coordinates of the center point A of the heart-shaped closed curve are x = -a, the coordinates of the depression point B of the heart-shaped closed curve are x = l-a, and the angle that r makes with the x-axis is θ, Sputtering characterized by existing in a region surrounded by a curve expressed by r=l−a+2a|θ|/π, (−π≦θ≦π), and a circle with radius l centered on point A. Device. (2) The sputtering apparatus according to claim 1, wherein a plurality of the magnets are successively integrated.