JPS63229852A - semiconductor equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] For the electrode wiring of a semiconductor device, polysilicon is used as the first layer and titanium nitride (TiN) and Ti or T are used as the second barrier layer.
By using iN and Ti silicide and aluminum for the third layer, electrode wiring with low contact resistance, good conductivity, and less disconnection can be obtained.

[Industrial application field]

The present invention relates to an electrode wiring structure for a semiconductor device, and more particularly to an electrode wiring having a three-layer structure with good conductivity and less disconnection.

Aluminum (AI) was first used for electrode wiring of semiconductor devices.
) were often used, but single-layer AI is prone to disconnection due to stress migration or electromigration. Therefore, the impurity-containing polysilicon (
There are some that are laid with poly-Si) to make it difficult to break the AI, or even if the AI breaks, the poly-St can be used to maintain heat.
This also has the disadvantage that A1 and polySt cause a dosing reaction, resulting in out-of-focus.

In the present invention, T is used as an intermediate layer between both the feed and poly-Si layers.
The purpose is to form iN and T473 or TiN-containing Ti silicide to obtain electrode wiring with good conductivity and no disconnection.

[Conventional technology]

FIG. 2 is a schematic cross-sectional view for explaining an electrode wiring structure in a conventional example.

In this figure, 1 is a Si substrate, and 2 is, for example, an N-type diffusion region formed in its surface layer.

An insulating film 3 such as a 5iOz film is formed on the surface of this Si substrate 1, and after a contact hole is opened in this, poly-Si4 doped with impurities is deposited by the CVD method, and then A16 is sputtered onto this. Covered by law. Next, A16 and poly SL4 are patterned to form an electrode wiring layer.

The AI-polySt electrode wiring formed in this way is A
Although the disconnection due to stress migration and electromigration can be considerably reduced compared to the single layer I layer, the heat treatment after electrode formation
It has a defect in which a solid phase reaction occurs between the i and St dissolves in solid solution in the AI, resulting in the generation of pits.

[Problem that the invention seeks to solve]

Solid phase reaction between Δl and poly-Si can be prevented and electrode wiring with good conductivity can be obtained.

[Means for solving the problem] The solution to the above problem is that the first layer of the electrode wiring layer led out from the surface of the silicon substrate is polysilicon containing impurities, and the second layer is made of titanium and titanium nitride. or titanium silicide and titanium nitride, and the third layer is aluminum.

[Effect]

A layer containing TiN is inserted as a barrier layer between the electrode wiring ^l and polySt. That is, a Ti layer is placed under the TiN ffj, or TiN and TiN silicide (TtSix
), it has low contact resistance and Al
- It is possible to obtain an electrode wiring having a three-layer structure with less reaction between poly-St.

〔Example〕

FIGS. 1(a) and 1(b) are schematic cross-sectional views for explaining the electrode wiring structure in the present invention.

FIG. 1(a) shows Example (1), in which 1 g of TiN and Til were used as a barrier layer between the aluminum and poly-Si.

Reference numeral 1 denotes a Si substrate, and an N-type diffusion region 2, for example, is formed in the surface layer of the Si substrate.

A 5iO1 film or PSG (Ph
After forming an insulating film 3 such as ospho-5ilicate glass and opening a contact hole in it,
No. 17 of poly-Si doped with impurities! ! Approximately 1,000 to 2,000 people will arrive using the CVD method. Next, approximately 200 layers of Ti5-1 are deposited on this layer by sputtering as a lower layer of the second layer.

Furthermore, about 1,500 TiN5-2 layers are formed on this layer by sputtering as an upper layer of the second layer. This sputtering is performed using a TiN electrode in Ar, or using a Ti electrode in an Ar+N atmosphere using a reactive sputtering method.

A third layer of A16 is applied to a thickness of approximately 1 μm by sputtering. Next, electrode wiring patterning is performed by anisotropic dry etching.

As a result, it is possible to form a second layer which is an intermediate layer having the good conductivity of TI and the good barrier properties of TiN.

FIG. 1(b) shows Example (2), in which a mixed layer of TiN and TiSi was used as a barrier layer between AI and poly-Si.

In this figure, 1 is a Si substrate, and an N-type diffusion region 2, for example, is formed in the surface layer of the Si substrate.

After forming an insulating film 3 such as SiO□ film or PSG on the surface of this Si substrate 1 and opening a contact hole in this, a first layer 4 of poly-Si doped with impurities is deposited by CVD to a thickness of about 1000~ 2,000 people arrive. Then, as a second layer, about 1000 Ti is deposited on top of this by sputtering.

Then, by annealing this in a nitrogen atmosphere at 950° C., silicidation and nitridation are simultaneously performed. That is, TiS gradually forms from the interface between Ti and poly-Si4.
i, is formed, and a second layer 5 rich in TiN is formed from the surface of Ti due to the diffusion of nitrogen.

As a result, the second layer 11 of the barrier layer is TiSix+T
Composed of iN, TiSi is highly conductive, and nitrogen in TiN prevents Si from entering TiSi.
No interaction between I and Si occurs, wire breakage is prevented, and electrode wiring with sufficiently low contact resistance can be obtained.

〔Effect of the invention〕

As described above in detail, according to the present invention, the electrode wiring of a semiconductor device includes poly-Si as the first layer, TiN as the second barrier layer, and l! : By using Ti or TiN and TtStX for the third layer, it is possible to prevent the reaction between poly-Si and AI, and to obtain electrode wiring with low contact resistance, good conductivity, and less disconnection. I can do it.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are schematic cross-sectional views for explaining an electrode wiring structure in the present invention, and FIG. 2 is a schematic cross-sectional view for explaining an electrode wiring structure in a conventional example. In this figure, 1 is a Si substrate, 2 is a diffusion region, 3 is an insulating film (Sift film), 4 is a first layer (poly-Si), and 5 is a second N layer. 5-1 is the second layer (Ti), 5-2 is the second layer (TiN), 6 is the third layer (A1)

Claims (1)

[Claims] In the electrode wiring layer led out from the surface of the silicon substrate (1), the first layer (4) is made of polysilicon containing impurities, and the second layer (5) is made of titanium, titanium nitride, or A semiconductor device comprising titanium silicide and titanium nitride, and a third layer comprising aluminum (6).