JPS62136018A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To suppress an increase in a contact resistance by bonding aluminum to a contacting surface with a semiconductor substrate at depositing speed of 20Angstrom /sec or lower. CONSTITUTION:The upper surface of an electrode window formed in an insulating film 14 of a silicon substrate 11 is covered with an aluminum film 12A by a sputtering method, for example, at a depositing speed of 5Angstrom /sec. When the thickness of the film becomes approx. 200Angstrom , it is covered with an aluminum film 12B to 0.3-5mum at a depositing speed of 100Angstrom /sec. Then, aluminum electrode wirings are formed by patterning by dry etching using chlorine gas. When covered at delay depositing speed in this manner, aluminum particles are finely dispersed. Accordingly, a reaction between the aluminum and the silicon is uniformized to suppress a solid-phase epitaxial growth. Thus, an increase in a contacting resistance between the aluminum and the silicon can be suppressed.

Description

Detailed Description of the Invention [Ia Required] Aluminum is deposited on the contact surface with the semiconductor substrate at a deposition rate of 20 Å/sec or less. This suppresses an increase in contact resistance.

[Industrial Field of Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming an aluminum electrode wiring.

As is well known, in semiconductor devices such as ICs, aluminum electrode wiring is provided on the semiconductor element, but this is because aluminum has low electrical resistance, low melting point, and
This is because patterning is easy and aluminum has good adhesion to semiconductor materials.

However, when such aluminum comes into contact with a semiconductor layer at an electrode portion, a large contact resistance is likely to occur on the contact surface, and sufficient consideration is desired to reduce this contact resistance.

[Problems to be solved by conventional technology and invention] Now,
As shown in FIG. 4, this increase in contact resistance is caused by the solid-phase epitaxial growth of silicon 3 entering the aluminum electrode at the contact surface between the silicon substrate 1 and the aluminum electrode 2 during the manufacturing process of the semiconductor device. This is because the high-resistance material is present on the contact surface. That is,
When a phosphorus silicate glass (PSG) film is grown as an interlayer insulating film or cover film of a semiconductor device,
Because of the high temperatures of 0 to 450 degrees Celsius, silicon and aluminum react at the aluminum-silicon interface to form an alloy, and then when the film growth process is stopped, the temperature drops and the silicon inside the aluminum is precipitated. Such a reaction is repeated during the manufacturing process, and a large solid phase epitaxial growth body 3 is formed on the aluminum electrode portion. Note that 4 in the figure is an insulating film made of a silicon oxide film.

Therefore, in order to reduce this contact resistance, various measures have been taken in the past. For example, as shown in FIG. 5, a method is known in which a tungsten film 5 is interposed on the contact surface. In this way, solid phase epitaxial growth can be prevented.

However, when a different type of conductor such as tungsten is interposed on the contact surface, a certain amount of contact resistance is unavoidable, the adhesion is not good, and patterning is difficult. Moreover, since tungsten or the like turns into silicide, it corrodes the silicon substrate 1, making it unsuitable for shallow junctions.

The present invention proposes a method for forming aluminum electrode wiring that eliminates these problems.

[Means for solving the problem] The problem is that in a semiconductor device manufacturing method in which electrode wiring made of aluminum is formed on a semiconductor substrate, aluminum is deposited on the contact surface with the semiconductor substrate at a deposition rate of 20 Å/second or less. The problem is solved by a method of manufacturing a semiconductor device that includes a step of depositing.

[Function] That is, the present invention provides a deposition rate of 2 on the contact surface with the semiconductor substrate.
Aluminum deposits at less than 0 Å/sec.

By doing so, increase in contact resistance between AI/S 4 is suppressed.

[Example] Hereinafter, embodiments will be described in detail with reference to the drawings.

As shown in FIG. 1 (al and bl are step-by-step cross-sectional views of the formation method according to the present invention. Fa in the same figure), sputtering is applied to the upper surface of the electrode window provided in the insulating film 14 of the silicon substrate 11. Aluminum film 12 was deposited at a deposition rate of 5 Å/s by
After depositing aluminum film 12B to a thickness of about 200, an aluminum film 12B is deposited to a thickness of 0.3 to 5 μm at a deposition rate of 100 Å/sec.

After that, patterning is performed by dry etching using chlorine-based gas to form an aluminum electrode wiring as shown in FIG.

If the aluminum particles are deposited at a slow deposition rate in this way, the aluminum particles are finely dispersed, so that the reaction between aluminum and silicon becomes uniform, and the growth of solid phase epitaxial growth is suppressed. Figure 2 shows a relationship chart (data of the implementation results) between the solid phase epitaxial growth rate and the deposition rate in the electrode cross section. From this chart, it can be seen that at a deposition rate of 20 Å/sec or less, almost no solid phase epitaxial layer is formed. It is clear that it is not growing.

Next, FIG. 3 is a sectional view showing another forming method according to the present invention. In this example, a film thickness of 500 to 500 μm is formed between an aluminum film 12A having a thickness of 200 μm and an aluminum film 12B having a thickness of 1 μm.
This is an example in which a titanium nitride (TiN) film 15 of 1,500 layers is interposed. In this method, in addition to the titanium nitride film 15, zirconium (Zr) and titanium (Ti) are used.

A metal film such as hafnium (Ilf), tantalum (Ta), tungsten (W), vanadium (V), or niobium (Nb), or a nitride film thereof can also be interposed.

According to the above-described formation method, the contact resistance on the aluminum electrode surface is stabilized, and the reliability of semiconductor devices such as ICs is significantly improved.

[Effects of the Invention] As can be seen from the above description, the present invention has a significant effect on increasing the reliability of semiconductor devices.

[Brief explanation of drawings]

1(a), (bl is a cross-sectional view of the formation process according to the present invention, FIG. 2 is a graph of the relationship between the solid phase epitaxial growth rate and the deposition rate, and FIG. 3 is a diagram of another formation method according to the present invention. Fig. 4 is a cross-sectional view showing the conventional method, and Fig. 5 is a cross-sectional view showing the conventional forming method. Aluminum film, 3 solid phase epitaxial growth body, 4.14 insulating film, 5 tungsten film, 12
A is an aluminum film deposited at a deposition rate of 20 Å/min or less, 12B is an aluminum film deposited at a deposition rate of 100 Å/min or more, 15 is a titanium nitride film. Figure 2 Figure 4 Figure 5E11

Claims (3)

[Claims] (1) A method for manufacturing a semiconductor device in which electrode wiring made of aluminum is formed on a semiconductor substrate includes a step of depositing aluminum on the contact surface with the semiconductor substrate at a deposition rate of 20 Å/second or less. A method for manufacturing a semiconductor device, characterized in that: (2) Deposit aluminum to the contact surface with the semiconductor substrate to a thickness of 100 to 1000 Å at a deposition rate of 20 Å/sec or less, and then deposit aluminum to the desired thickness at a deposition rate of 100 Å/sec or more. 2. A method of manufacturing a semiconductor device according to claim 1, further comprising the step of: (3) Deposit aluminum on the contact surface with the semiconductor substrate at a deposition rate of 20 Å/sec or less, then deposit a metal film or metal nitride film, and then deposit aluminum at a deposition rate of 100 Å/sec or more. 2. A method of manufacturing a semiconductor device according to claim 1, further comprising a step of depositing the semiconductor device to a film thickness of .