JPH05114599A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device having a resistance to either of an electro-migration and a stress migration by a method wherein a wiring layer is constituted of a laminated material consisting of two or more layers of an Al metal layer of a large crystal grain diameter and an Al metal layer of a small crystal grain diameter. CONSTITUTION:An insulating film 2 is formed on a semiconductor substrate 1, then, an Al metal is used as a vaporation source and an Al metal layer 3 of a large crystal grain diameter is formed at a first temperature using a sputtering method. Then, Al metal layer 4 of a crystal grain diameter smaller than the above crystal diameter is formed at a second temperature lower than the first temperature. Moreover, the layers 3 of the large crystal grain diameter and the layers 4 of the smaller crystal grain diameter are arbitrarily laminated repeatedly and a wiring layer is formed to manufacture a semiconductor device. As the Al metal, Al-Si, Al-Si-Pd or the like is exemplified. The first temperature is normally 150 deg.C or higher, desirably 300 deg.C or higher. The second temperature is normally 100 deg.C or lower, desirably 50o<= or lower.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As semiconductors become finer, wiring film (especially Al alloy film) electromigration (E
M), stress migration (SM), and the like have reduced reliability, which has become a serious problem. As a conventional EM countermeasure, other metal impurities (such as Cu and T) are contained in Al.
(i, Pd, etc.) or by increasing the size of the crystal grain system to form a crystal grain boundary having a so-called bamboo knot (bamboo) structure. Further, as SM countermeasures, of course, reduction of stress of the insulating film covering the wiring film is considered, and as countermeasures on the material side, mixing of metal impurities and suppression of crystal grain size are considered as in EM countermeasures.

Further, a laminated film of Al alloy and refractory metal or A
A method has been considered in which, during the film formation of l, the film is taken out of the apparatus once, a thin oxide film is attached to the surface thereof, and Al is further deposited thereon.

[0004]

However, the wiring layer made of an Al-based alloy containing impurities has a problem that the mechanical strength becomes weak due to the influence of corrosion and uneven deposition. The wiring layer having crystal grain boundaries has a problem that the SM resistance deteriorates. The present invention has been made to solve the above problems, and is provided with a highly reliable Al-based metal that is resistant to both EM and SM without corrosion and without complicating the process. Another object of the present invention is to provide a semiconductor device and a manufacturing method thereof.

[0005]

According to the present invention, two or more layers of an Al-based metal layer having a large crystal grain size and an Al-based metal layer having a small crystal grain size are provided on a semiconductor substrate through an insulating layer. There is provided a semiconductor device including a wiring layer formed of a laminated body. In the present invention, the wiring layer is arranged on the semiconductor substrate via the insulating film.

A silicon substrate is usually used as the semiconductor substrate. In addition, elements are usually formed in advance on this semiconductor substrate. The insulating film is for insulating a region other than the contact region of the semiconductor substrate from the wiring layer,
For example, it is formed of silicon oxide, silicon nitride, or the like.

The above wiring layer is for inputting / outputting signals to / from the semiconductor device with high reliability, has no corrosion, and has resistance to both EM and SM without complicating the manufacturing process. Good quality, large grain size Al
It is composed of a laminate of two or more layers of a system metal layer and an Al system metal layer having a small crystal grain size. The Al-based metal layer having a large crystal grain size is
The crystal grain size is preferably large enough to suppress EM, and is usually 5000 Å or more, preferably 10,000 Å or more. The film thickness is usually 0.2 to 1.0 μm.

The Al-based metal layer having a small crystal grain size preferably has a crystal grain size small enough to suppress SM.
It is not more than 00Å, preferably not more than 3000Å. The film thickness is usually 0.2 to 1.0 μm. In the above-mentioned laminated body, an Al-based metal layer having a large crystal grain size and an Al-based metal layer having a small crystal grain size can be arbitrarily arranged, but the EM resistance is first large on the semiconductor substrate on which the insulating film is formed. An Al-based metal layer having a crystal grain size is disposed, and an Al-based metal layer having an arbitrarily small crystal grain size and an Al-based metal layer having a large crystal grain size are repeatedly stacked on the insulating layer, and an insulating layer covering the upper part of the laminated body. It is preferable to dispose an Al-based metal layer having a small crystal grain size having a small SM resistance in a layer in contact with.

The semiconductor device of the present invention can be manufactured, for example, as follows. That is, an insulating film is formed on a semiconductor substrate, an Al-based metal layer having a large crystal grain size is formed at a first temperature by using a sputtering method using an Al-based metal as an evaporation source, and a first lower temperature than the first temperature is formed. An Al-based metal layer having a smaller crystal grain size is formed at a temperature of 2, and an Al-based metal layer having a larger crystal grain size and an Al-based metal layer having a smaller crystal grain size are repeatedly laminated to form a wiring layer, thereby forming a semiconductor device. To manufacture.

The Al-based metal is, for example, Al or Al-S.
i, Al-Si-Pd, Al-Si-Cu, Al-Si
-Ti etc. can be mentioned. The first temperature is a substrate temperature for forming an Al-based metal layer having a crystal grain size capable of suppressing EM on the substrate by a sputtering method, and is usually 150 ° C or higher, preferably 300 ° C or higher. ..

The second temperature is E by the sputtering method.
A substrate temperature for forming an Al-based metal layer having a crystal grain size capable of suppressing SM on an Al-based metal layer having a crystal grain size capable of suppressing M, usually 100 ° C. or lower, preferably 50 ° C. It is below. In the present invention, the semiconductor device can be manufactured by forming the insulating layer on the semiconductor substrate on which the wiring layer is formed.

[0012]

[Function] An Al-based metal layer having a large crystal grain size laminated at a substrate temperature of 300 ° C or higher suppresses electromigration, and an Al-based metal layer having a small crystal grain size laminated at a substrate temperature of 50 ° C or less causes stress migration. Suppress.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The scope of application of the present invention is not limited by this embodiment. As shown in FIG. 1A, a silicon substrate 1 having an insulating film 2 formed on its surface is placed in a sputtering apparatus and heated to 400 ° C., and Al—Si—Pd is used as an evaporation source to form a film with a sputtering method. 0.4 μm Al-Si-P
The d film 3 is formed. A that constitutes the Al-Si-Pd film 3
The crystal grain size of 1-Si-Pd is 20000 to 40,000.
It is Å.

Next, as shown in FIG. 1B, Al--Si--
The temperature of the substrate on which the Pd film 3 is formed is lowered to 25 ° C., and again the Al-Si-P film having a thickness of 0.4 μm is formed by the sputtering method.
The d film 4 is formed. A that constitutes the Al-Si-Pd film 4
The crystal grain size of l-Si-Pd is 1000 to 3000Å. Next, the Al-Si-Pd film 3 and the Al-Si-Pd film 4 are etched into a predetermined pattern by photolithography to form a wiring layer, and a semiconductor device is manufactured.

[0015]

According to the present invention, a semiconductor device provided with a highly reliable Al-based wiring layer having resistance to both electromigration and stress migration without complicating the process and a method for manufacturing the same are provided. Can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a manufacturing process of a semiconductor device manufactured in an example of the present invention.

[Brief description of symbols] 1 silicon substrate 2 insulating film 3 Al-Si-Pd film 4 Al-Si-Pd film

Claims (2)

[Claims] 1. A wiring layer comprising a laminate of two or more layers of an Al-based metal layer having a large crystal grain size and an Al-based metal layer having a small crystal grain size is provided on a semiconductor substrate via an insulating layer. Semiconductor device. 2. An insulating film is formed on a semiconductor substrate, and then an Al-based metal layer having a large crystal grain size is formed at a first temperature by a sputtering method using an Al-based metal as an evaporation source. An Al-based metal layer having a smaller crystal grain size is formed at a lower second temperature, and an Al-based metal layer having a larger crystal grain size and an Al-based metal layer having a smaller crystal grain size are repeatedly laminated to form a wiring layer. The method for manufacturing a semiconductor device according to claim 1, wherein