JPH05299418A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a method for the manufacture of a highly reliable semiconductor device. CONSTITUTION:A method for the manufacture of a semiconductor device composed of a process for forming a contact hole 3 in an insulating film 2 on a semiconductor substrate 1; a process for forming a high melting point conductive thin film 4 on the substrate 1 by sputter deposition; and a process for tapering the side wall of the above contact hole by argon sputtering. The wet etching process for tapering a contact hole is omitted, and thus the possibility of resist being stripped during the process; argon sputtering in a sputtering system is employed for tapering a contact hole 3 instead. This enables the formation of an aluminum wiring 7 excellent in step coverage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a highly integrated and highly reliable semiconductor device.

[0002]

2. Description of the Related Art As the density of semiconductor devices increases, the ratio of the interlayer insulating film thickness to the diameter of connection holes (aspect ratio) increases, and the contact holes become deeper. In some cases, the step coverage in the contact hole deteriorates, which may lead to disconnection in the initial stage. Note that, here, a wiring made of an Al-X (X; additive impurity) alloy containing Al element as a main component is referred to as an aluminum wiring. Furthermore, the miniaturized aluminum wiring has stress migration caused by tensile stress of the surrounding interlayer insulating film and passivation film during the heat treatment during the process after forming the aluminum wiring and during the actual operation after assembling the semiconductor chip. There is a problem that the aluminum wiring is broken due to the electromigration induced by.

Conventionally, as a method of forming a structure of a connection hole in a semiconductor device, as shown in FIG. 2, an insulating film 2 is formed on a silicon substrate 1 on which a semiconductor element is formed, and a photoresist is further applied. After forming a contact hole in the insulating film 2, the contact hole is tapered by a wet etching method and the resist is removed to form a tapered contact hole 5. Then, the TiN / Ti thin film 6 and the Al-1% Si-0.5% Cu thin film 7 are generally deposited as the barrier metal layer.

[0004]

However, in the above method for forming a tapered contact hole, a wet etching step is required before the aluminum wiring forming step, and the insulating film and the resist are not formed after the wet etching step. Due to the poor adhesion, there is a problem that the resist peels off. In view of the above problems, it is an object of the present invention to provide a method for manufacturing a semiconductor device in which a tapered contact hole is surely formed and the process is simplified.

[0005]

In order to solve the above problems, the method of manufacturing a semiconductor device according to the present invention does not require a wet etching process and forms a tapered contact hole by argon sputtering in a sputtering device. It is what makes them. More specifically, the method of manufacturing a semiconductor device of the present invention comprises a step of forming a connection hole in an insulating film on a semiconductor substrate, a step of forming a refractory conductive thin film on a substrate by a sputter deposition method, and then an argon sputtering method. And a step of forming a slope on the side wall of the continuous hole, so that damage to the semiconductor substrate is suppressed.

[0006]

According to the present invention, the manufacturing method of a semiconductor device can be simplified by the method described above, the contact hole can be easily tapered, and the step coverage of aluminum wiring can be improved to manufacture a highly reliable semiconductor device. it can.

[0007]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a manufacturing process of a semiconductor device according to an embodiment of the present invention. In FIG. 1a, a silicon substrate 1 on which a semiconductor element is formed has a thickness of 800 nm.
The insulating film 2 is formed, a contact hole 3 is opened in the insulating film 2, and then a 80 nm Ti thin film 4 is deposited as a high melting point conductive thin film.

Subsequently, in FIG. 1B, in the sputtering apparatus, the entire surface of the wafer is subjected to argon sputtering (reverse sputtering) under the conditions of a vacuum degree of 10 mTorr and a power of 360 W, and the corners of the contact holes 3 are etched to form tapered contact holes 5. At that time, a Ti thin film 4 was formed on the bottom of the hole.
Are partially left, and damage to the silicon substrate 1 can be prevented.

Next, in FIG. 1c, 100/20 nm Ti is used as a barrier metal layer on the reverse-sputtered Ti thin film 4.
The N / Ti thin film 6 is deposited. Since the Ti thin film remains at the bottom of the hole at the stage of FIG. 1b, the TiN / Ti thin film 6 is thick at the bottom and also thick at the side wall due to the taper, so that the barrier property can be improved. Above, Ti deposition (Fig. 1
The steps from a) to TiN / Ti deposition (FIG. 1c) are continuously performed in the sputtering apparatus.

Next, in FIG. 1d, the wafer is once exposed to the atmosphere to secure the barrier property, and then the 800 nm Al-1% Si-0.5% Cu thin film 7 is deposited again by the sputtering apparatus. Since the taper is formed, good step coverage of the aluminum thin film can be maintained.

As described above, in this embodiment, the Ti thin film 4 is deposited before the barrier metal layer TiN / Ti thin film 6 is deposited, and then the reverse sputtering is performed to taper the contact hole 3. The damage of can be suppressed.

Since the argon sputtering conditions for taper in this embodiment differ depending on the shape of the sputtering apparatus and the like, the degree of vacuum is 1 to 500 mTorr and the power is 10 to 600 W.
This can be done by optimizing with.

[0014]

As described above, the present invention eliminates the need for a wet etching step for forming a tapered contact hole, eliminates the possibility of resist stripping in that step, and makes the sidewall of the contact hole tapered. By improving the step coverage of the aluminum wiring, it is possible to form an aluminum wiring having a strong resistance to electromigration and stress migration, which greatly contributes to the manufacture of ultrafine semiconductor devices.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device manufacturing process according to an embodiment of the present invention.

FIG. 2 is a sectional view of a semiconductor device according to a conventional method.

[Explanation of symbols]

 1 Silicon substrate 2 Insulating film 3 Contact hole 4 Ti thin film 5 Tapered contact hole 6 TiN / Ti thin film 7 Al-1% Si-0.5% Cu thin film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication H01L 21/90 C 7735-4M (72) Inventor Shinichi Ogawa 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Sangyo Co., Ltd.

Claims (1)

[Claims] 1. A step of forming a connection hole in an insulating film on a semiconductor substrate, a step of forming a high-melting-point conductive thin film on a substrate by a sputter deposition method, and then forming a slope on the side wall of the contact hole by an argon sputtering method. The method of manufacturing a semiconductor device, comprising: