JPS619568A - Formation of coated film - Google Patents

Abstract

PURPOSE:To make the thickness of an Al film in a recess uniform by changing periodically the angle of the substrate surface with a target when the Al film is formed on the substrate of a semiconductor chip having plural recesses for contact holes on the surface by sputtering. CONSTITUTION:Al fine particles M formed by Ar ions from the radiation surface 4 of an Al target 3 are radiated in an Ar atmosphere on the surface of a substrate 1 to be coated having plural recesses 5 as contact holes to form an Al thin film on the surface 2 of the substrate 1 to be coated by sputtering. In this case, since the thickness of the Al coated film 6 is changed by the position of the recess 5 on the surface to be coated, a table 11 fixed to the substrate 1 is rotated in the directions as shown by the arrows 7 and 8 with the X-axis and the Y-axis as the axis of rotation through the expansion and contraction of a hinge 12 and four rods 13 to change the angle with the target 3. Accordingly, the thickness of the Al coated film 6 in the recesses 5 at the central part and the peripheral part of the coated surface 2 is made uniform.

Description

Detailed Description of the Invention +a+ Industrial Field of Application The present invention relates to a method of forming a deposited film, and in particular, it relates to a method of forming a deposited film on a substrate for manufacturing a semiconductor chip, which is a main component of a semiconductor device, by, for example, a sputtering method. This invention relates to a method of forming a deposited film when depositing a material for forming an electrode.

There is no need to explain that semiconductor devices are used in a wide variety of fields due to their convenience, but their main component, the semiconductor chip, is generally a semiconductor device with semiconductor elements such as transistors formed on a semiconductor substrate (wafer). Its reliability depends not only on the quality of the semiconductor element itself, but also on
The quality of wiring lead-out from the semiconductor element also has a large influence.

(b) Prior Art The above-mentioned wiring derivation usually involves forming a contact hole in an insulating film covering the semiconductor element, depositing an electrode material such as aluminum on the contact hole by sputtering, etc., and depositing this deposited film. This is done by patterning to form electrodes and wiring. At this time, the quality of the wiring lead-out depends on the quality of coverage in the contact hole portion of the deposited film.

FIG. 2 ta+ is a perspective view showing the configuration of main parts in a conventional general sputtering method, in which 1 is a substrate on which a film is formed by sputtering, 2 is a surface to which the film is deposited, and 3 is a material body for the deposited film called a target. , 4 is the radiation surface that emits the material. Additionally, x, y, and z axes are added to the figure for convenience of understanding.

That is, if the adherend surface 2 is the X2 plane and the Y axis passes through the center of the adherend surface 2, then the radiation surface 4 is from the adherend surface 2 to the adherend surface 2.
They are spaced apart from each other in the front Y-axis direction, are centered on the Y-axis, and are disposed facing the adherend surface 2. Spacing is usually 50-6
It is about 0 days.

The deposition film is formed by sputtering at approximately 10-Torr.
By making the above arrangement in an argon atmosphere of about 100 mL, using the deposited film material 3 as a cathode, and discharging between it and an anode (not shown), argon ions Ar are emitted onto the radiation surface 4.
The material M of the deposited film material body 3 is radiated from the radiation surface 4 by being hit, and the material M is deposited on the deposition surface 2.

At this time, if the size of the deposited film material body 3 is made approximately 1.5 times the size of the substrate 1 (for example, the diameter), the thickness of the deposited film formed on the deposited surface 2 will be increased to the entire surface. It is empirically known that the migration is approximately equal.

(C) Problems to be Solved by the Invention However, in cases where the above-mentioned contact hole is provided, the adherend surface 2 has a depression as shown in FIGS. 2(b) and 2(C) (both side sectional views). 5, the thickness of the deposited film 6 is
It is not uniform in the depression 5 part.

That is, Figure (bl) shows the case where the recess 5 is located at the center of the adherend surface 2, and Figure (C) shows the case where the recess 5 is located at the periphery of the adherend surface 2 (the upper part shows the center side and the lower part shows the edge side). ), and the diagram shows (
The thicknesses Tl and T2 of the deposited film 6 at the shoulder of the depression 5 in the central part shown in FIG. The thickness of the deposited film 6 is different between the upper side (T3) and the lower side (T4) in the figure.
The thickness T4 is thinner.

This tendency becomes more noticeable as the base body 1 becomes larger.

For example, the base body 1 has a depression 5 with a size of about 2 μm square and a depth of about 1 μm, and a diameter of about 150 fiφ, that is, a contact hole 6! For a large wafer of diameter φ, the thickness T is approximately 1
When aluminum (material M) is deposited to a thickness of μm (sputtering time approximately 1 minute), the thickness of the shoulder portion of the recess 5 is T1 to T4.
Among them, the thicknesses T1 to T3 are approximately equal to about 172 times the thickness T, but the thickness T4 becomes extremely thin when it is less than 172 times the thickness T3.

For example, in the wiring derivation of a semiconductor chip, as the wafer (substrate) becomes thicker, the coverage in the contact hole area at the periphery of the wafer deteriorates, leading to the risk of disconnection in that area. .

(d) Means to solve the problem The above problem is
This can be solved by taking a method of periodically changing the angle formed between the substrate adhering surface and the direction from the adhering surface toward the material when emitting the material of the adhering film material. .

(e) Effect In the illustrations in FIG. 2 1al and (C), the thickness T4 is thin because the radiation of the material M is not uniformly distributed over the entire surface of the radiation surface 4, and the density of the radiation is not uniform in the direction. Depending on the
This is thought to be due to the fact that there are few lateral components toward the edge in the peripheral area of the adherend surface 2.

Therefore, by tilting the deposition surface 2 with respect to the radiation surface 4, the radiation in the direction in which the radiation density of the material M is greater than that in the horizontal direction is utilized, and the thickness T4 is thicker than in the past. It becomes possible to form.

However, this effect does not change even if the base 1 becomes larger; in fact, considering that in the conventional method, the thickness T4 becomes thinner as the base 1 becomes larger, the effect is greater when the base 1 is larger. .

If the inclination is fixed, the thickness T4 will become thicker and uneven in only one direction on the adherend surface 2. Therefore, in the present invention, the inclination is periodically changed to increase the thickness T4 depending on the direction on the adherend surface 2. It eliminates bias.

Thus, for example, in leading out the wiring in a semiconductor chip, even if the wafer (substrate) becomes larger, it is possible to improve the coverage in the contact hole portion and reduce the risk of disconnection in that portion.

Note that the principle of this method is not limited to the sputtering method shown in the conventional example, but the method involves emitting the material of the deposited film material from a deposited film material disposed in front of the substrate deposition surface. The present invention is also effective when applied to a method of forming a deposited film of the material on the surface to be deposited, such as a vapor deposition method.

(f) Example Hereinafter, an example of the method for forming a deposited film according to the present invention will be explained with reference to FIG. The same reference numerals refer to the same objects throughout the design.

In FIG. 1, FIG.
b) and Fig. (C) are side sectional views showing an example of a state in which a coating film is applied according to the embodiment.

The illustration in FIG. 1(a) corresponds to the illustration in FIG. 2(a), but in the illustration in FIG. It is designed to rotate. Other details are the same as shown in Figure 2+a). arrow 7
The rotation of arrow 8 changes the angle θ2 between the adherend surface 2 and the Y-axis in the YZ plane by about 30 degrees, and the rotation of arrow 8 changes the angle θX between the adherend surface 2 and the Y-axis in the XY plane. This gives a change of about 30 degrees to the surface. However, since the rotation period of arrow 7 is about 5 seconds and the rotation period of arrow 8 is about 6 seconds, the re-rotation period is different.
In all directions in , the angle between the adherend surface 2 and the Y axis changes by about 30 degrees.

In addition, the main part configuration of the example of the sputtering apparatus that provides the rotation is as follows:
As shown in a side sectional view in FIG. 1 fd).

The table 11 to which the base body 1 is fixed is supported at the center of its back surface via a hinge 12 and can swing freely. They are pushed by the rods 13 and rotate as indicated by arrows 7 and 8 in FIG. 1 fa).

In this method, for example, similar to the conventional embodiment described above,
The base body 1 has a depression 5 with a size of about 2 μm square and a depth of about 1 μm, and a diameter of about 15 ONφ, that is, a contact hole 6! The results of depositing aluminum (material M) on a large wafer of diameter φ to a thickness T of approximately 1 μm (sputtering time approximately 1 minute) are as shown in FIG. 1 (fbl and fc).

That is, although the illustrations in FIG. 1 (bl and (C1) correspond to the illustrations in FIG. 2 (b) and (C), respectively,
) and the thicknesses T1 to T3 shown in te1 are as shown in Fig. 1(b).
and (C) the thicknesses are almost unchanged from the illustrated thicknesses T1 to T3. On the other hand, the thickness T4 shown in FIG. 1 fc1 is approximately 374 times the thickness T3, and the thickness T4 shown in FIG.
It's more than 5 times more.

(Effects of the Invention As explained above, by taking the measures of the present invention, as the substrate becomes larger, the thickness of the deposited film on the shoulder of the depression in the periphery of the deposited surface decreases. For example, even when the wafer (substrate) becomes larger, it is possible to suppress the thinning of the wiring in a semiconductor chip, and even if the wafer (substrate) becomes larger, the coverage in the contact hole area can be improved, and there is a risk of disconnection in that area. This has the effect of making it possible to reduce the

[Brief explanation of the drawing]

FIG. 1+a) is a perspective view showing the main structure of an embodiment of the sputtering method according to the method of the present invention, and FIG. 1(d) is a side sectional view showing the configuration of the main parts of an example of a sputtering apparatus that rotates the substrate; FIG. FIG. 2(b) is a perspective view showing the structure, and FIG. 3 is the deposited film material body, 4 is the radiation surface, 5 is the depression, 6 is the deposited film, 7.8 is the arrow,
11 is a table, 12 is a hinge,
13 is the rod, Ar is the argon ion, L is the spacing, M is the material, T, Tl~T4 are the thickness, θx
102 indicates the angle, respectively. Mine Utat #2nd

Claims (1)

[Claims] When forming a coating film of the material on the coating surface by emitting the material of the coating material body disposed in front of the substrate coating surface, the coating material body is disposed in front of the coating surface. A method for forming a deposited film, characterized in that the angle between the surface and the direction from the deposited surface toward the material body is periodically changed.