JPH0362025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to the structure of a semiconductor device, and particularly to a method for attaching aluminum alloy wiring containing silicon.

(b) Prior art and problems In semiconductor devices such as semiconductor integrated circuits (ICs), aluminum (containing about 1 to 2%) of silicon (Si) is used in the semiconductor layer, that is, the wiring directly in contact with the functional area. Al) alloy wiring is often used. This is because the temperature of the wiring is raised to about 400 to 500 degrees Celsius during processes such as chemical vapor deposition of the surface protection insulating film, chip bonding, and case sealing that are performed after the wiring is formed. At this time, this is to prevent Si in the functional area in contact with the Al wiring from dissolving into Al and destroying the bond in the functional area.

However, when using the above-mentioned Al alloy wiring containing Si, if the heating process is carried out after wiring formation as described above, excessive Si contained as an alloy component in the Al wiring will be removed at room temperature. Al-doped p-type Si crystals are precipitated on the surface of the Si layer, that is, the functional region, in contact with the Al alloy wiring.

Therefore, especially when the Al alloy wiring is derived from the n-type functional region, there is a p-n There is a problem that a junction is formed and the contact resistance of the wiring increases.

As shown in the top view A and the cross-sectional view B in FIG. When a bonding pad 5 having a large area is formed on the Al alloy wiring 4, a large amount of p that has moved from the bonding pad portion is deposited on the surface of the n-type functional region 2 exposed in the electrode contact window 1. When the type Si crystal 6 is precipitated and the semiconductor IC is further integrated with high density and the electrode contact window 1 is miniaturized, the entire surface of the n-type functional region 2 exposed within the contact window 1 is Covered with p-type Si crystal 6, the Al alloy wiring 4 becomes non-conductive to the n-type functional region 2. (In the figure, 7 is p
type Si substrate, 8 is a field oxide film, 9 is a thin oxide film) (c) Object of the Invention The present invention provides a semiconductor device using an aluminum alloy containing silicon in a wiring body, However, the present invention provides a wiring attachment structure that suppresses the deposition of metal on the functional area exposed in the electrode contact window, and its purpose is to eliminate the above-mentioned problems and improve the performance and reliability of semiconductor devices. The purpose is to improve sexuality.

(d) Structure of the Invention In other words, the present invention provides a semiconductor device including a first diffusion region having n-type and constituting an element, and a first diffusion region adjacent to the first diffusion region and connected to the first diffusion region. and an n-type second diffusion region arranged separately.
an insulating film disposed on the semiconductor substrate and having first and second openings reaching the surfaces of the first diffusion region and the second diffusion region; an n-type silicon crystal deposited on the second diffusion region, and an n-type silicon crystal that is led out from the surface of the first diffusion region through the first opening onto the insulating film, and in contact with at least the n-type silicon crystal through the
Moreover, it is characterized in that it further includes an aluminum alloy wiring containing silicon extending from the second opening onto the insulating film.

(e) Embodiments of the Invention The present invention will be described below in detail regarding one implementation in a MOS type semiconductor device with reference to a schematic top view of the main part shown in FIG. do.

A MOS type semiconductor device to which the present invention is applied includes, for example, a field interconnection film 12 on a p-type silicon (Si) substrate 11 and a p ⁺ -type channel cut region below it, as shown in FIGS. 2A and 2B. A first substrate surface exposing area 14 and a second substrate surface exposing area 15 are provided adjacent to each other and separated by individual boundaries 13, and the first substrate surface exposing area 14
For example, an n-channel MOS transistor (Tr) composed of a gate oxide film 16, a polycrystalline Si gate electrode 17, an n ⁺ type source region 18, and an n ⁺ type drain region 19 is also exposed on the second substrate surface. Area 1
5, n ⁺ -type dummy diffusion regions 20 are formed, which have a depth equal to that of the source and drain regions 18 and 19, for example, about 3,000 to 5,000 Å, and which do not constitute an element.

An insulating film 21 made of, for example, phosphosilicate glass (PSG) is disposed on the substrate, and the source region 18 and the drain region 1 are covered with the insulating film 21.
9. The first, second, and
Third contact window (opening) 22a, 22b, 2
2c is provided. Then, on the insulating film 21, a source wiring 23a made of, for example, an Al-Si alloy containing about 1% of Si and the second It is led out from the surface of the drain region 19 through the contact window 22b, contacts at least the silicon crystal 25 through the third contact window 22c, further extends from the third contact window 22c onto the insulating film 21, and has a tip. The bonding pad 2 has a large area of, for example, about 100 [μm] square.
A drain wiring 23b made of the Al--Si alloy is formed, and the drain wiring 23b is made of the Al--Si alloy.

That is, in this embodiment, the n ⁺ type drain region 1
A large area of bonding is provided at the tip of the insulating film 21 from the contact window 22b through the contact window 22b.
Al-Si alloy drain wiring 2 with pad 24
3b is located between the contact window 22b on the drain region 19 and the bonding pad 24, and contacts the silicon crystal 25 formed on the n ⁺ type dummy diffusion region 20 that does not constitute a device through the contact window 22c. I am forced into contact with them.

Therefore, in this structure, after the wiring formation is completed, the Al-Si alloy drain wiring is formed in the process of forming a surface protection insulating film (for example, a cover PSG film), chipping, bonding, and sealing the case. is from 350
After undergoing a thermal history of about 450 degrees Celsius, a large amount of Si contained in the large bonding pad portion becomes p-type crystal 25 mainly on the dummy diffusion region 20 exposed in the contact window 22c. Therefore, the amount of p-type Si crystal 25 deposited on n ⁺ -type drain region 19 in contact window 22b becomes extremely small. Therefore, in this embodiment, the contact resistance of the Al-Si alloy drain wiring 23b having a bonding pad to the drain region 19 is made equal to the contact resistance of, for example, the source wiring 23a, which does not have a large area such as a bonding pad. could be formed to a low value.

In the above embodiment, the contact portion (dummy contact portion) between the Al-Si alloy wiring and the silicon crystal 25 is bonded to the contact portion with the functional region (drain region) of the Al-Si alloy wiring.・Although one dummy contact portion is provided between the pad portions, two or more dummy contact portions may be provided in series or in parallel to further enhance the effect. In this case, the dummy diffusion region may be formed as one region and used in common, or may be provided individually.

Also, providing the above dummy contact part,
The same effect as described above is produced not only for wirings having bonding pads but also for wirings extending long from a functional area onto an insulating film.

(f) Effects of the Invention As explained above, according to the present invention, when an aluminum alloy containing silicon is used as the wiring material of a semiconductor device, silicon moves through the wiring due to the heat load applied after the wiring is formed. is prevented from reaching the contact area between the wiring and the area that functions as an electric circuit, so the amount of p-type silicon crystal deposited in the contact area is significantly reduced, and the amount of p-type silicon crystal deposited in the contact area is significantly reduced. Contact resistance to the functional area is reduced. This effect of reducing contact resistance is particularly remarkable for the n-type functional region.

Therefore, according to the present invention, it is possible to improve the performance and reliability of a semiconductor IC using an aluminum alloy containing silicon as a wiring material.

[Brief explanation of drawings]

Fig. 1 is a top view A and a cross-sectional view B showing a conventional wiring installation structure, and Fig. 2 is a schematic top view A and its A-A It is a cross-sectional view B as viewed from the arrow. In the figure, 11 is a p-type silicon substrate, 12 is a field oxide film, 13 is a p ⁺ type channel cut region, 14 is a first substrate surface exposed region, and 15 is a second
16 is a gate oxide film, 17 is a polycrystalline silicon gate electrode, 18 is an n ⁺ type source region, 19 is an n ⁺ type drain region, 20 is an n ⁺ type dummy diffusion region, and 21 is an insulation region. membrane, 22a, 22
b, 22c are contact windows, 23a is an aluminum-silicon alloy source wiring, 23b is an aluminum-silicon alloy drain wiring, 24 is a bonding pad, and 25 is a deposited p-type silicon crystal.

Claims (1)

[Claims] 1. A first n-type diffusion region constituting an element, and an n-type second diffusion region adjacent to and separated from the first diffusion region. a p-type semiconductor substrate having a p-type semiconductor substrate; an insulating film having first and second openings disposed on the semiconductor substrate and reaching the surfaces of the first diffusion region and the second diffusion region; An n-type silicon crystal deposited on the second diffusion region surface in the opening, and an n-type silicon crystal deposited on the insulating film from the first diffusion region surface through the first opening an aluminum alloy wiring containing silicon, which is in contact with at least the n-type silicon crystal through the second opening, and further extends from the second opening onto the insulating film. semiconductor device.