Semiconductor device with a dual damascene type via contact...

Details Semiconductor device with a dual damascene type via contact... Semiconductor device with a dual damascene type via contact...

1998-05-29

2002-08-13

Chaudhuri, Olik (Department: 2814)

Active solid-state devices (e.g., transistors, solid-state diode

Combined with electrical contact or lead

Of specified material other than unalloyed aluminum

C257S773000

Reexamination Certificate

active

06433428

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device with a dual damascene type via contact structure and a method for the manufacture of same and, more particularly, to an improvement in or relating to the via contact filling layer portion of the semiconductor device.
For the formation of wiring layers, the damascene technique has so far been employed. The manufacturing steps thereof are simple, and in addition, it is required to apply no RIE treatment step to the metal layers. It is difficult to form fine metal patterns by the use of the RIE step.
FIGS. 27
to
33
are, respectively, sectional views showing the structure at the respective manufacturing steps in the case of forming a via contact wiring structure by the use of the RIE method.
FIGS. 34
to
39
are, respectively, sectional views showing the structure at the respective manufacturing steps in the case of forming a dual damascene type via contact by the use of the damascene method.
According to the RIE method, first, on the upper surface of a semiconductor substrate
12
on which a first metal wiring layer, normally an aluminum wiring layer
22
is formed, a first inter-layered insulation film
24
is formed by the use of the CVD (Chemical Vapor Deposition) method as shown in
FIG. 27
(Step
1
). Next, as shown in
FIG. 28
, a via contact hole
32
is formed by performing an RIE treatment in the inter-layered insulation film
24
(Step
2
). Between the semiconductor substrate
12
and the first aluminum wiring layer
22
, a barrier layer
14
composed of SiO
2
is provided. Subsequently, as shown in
FIG. 29
, tungsten is deposited, by the use of the sputtering method, to form a tungsten layer
62
over the whole surface of the semiconductor substrate
12
having the structure processed as mentioned above, whereby the via contact hole
32
is filled up with said tungsten as shown in
FIG. 29
(Step
3
), Then, the tungsten on the upper surface of the inter-layered insulation film
24
is removed by performing a CMP (Chemical-Mechanical Polishing) treatment, so that, as shown in
FIG. 30
, the tungsten is left only in the via contact hole to form a via contact filling layer
38
(Step
4
). Subsequently, on the whole upper surface of the semiconductor substrate
12
having the structure thus processed, a metal wiring material, which is normally aluminum, is deposited by the use of the CVD method or the sputtering method, whereby a metal wiring material layer
64
is formed as shown in
FIG. 31
(Step
5
). Then, the thus formed metal wiring material layer
64
is patterned by an RIE treatment to form a second metal wiring layer
66
as shown in
FIG. 32
(Step
6
). Subsequently, over the whole surface of the semiconductor substrate
12
having the structure thus processed, a second inter-layered insulation film
68
is formed by the use of the CVD method (Step
7
).
On the other hand, in the case of employing the damascene method, first, as shown in
FIG. 34
, a first thick inter-layered insulation film
24
is formed, by the use of the CVD method, on the upper surface of a semiconductor substrate
12
on which a first metal wiring layer
22
, normally an aluminum wiring layer, is formed (Step
1
). Then, as shown in
FIG. 35
, on the inter-layered insulation film
24
thus formed, a via contact hole
32
is formed by an RIE treatment (Step
2
). Next, as shown in
FIG. 36
, a shallow wiring groove
28
is formed, by an RIE treatment, in a portion of the inter-layered insulation film
24
which portion includes the upper portion of the via contact hole. As a result, there is formed a dual damascene type via contact structure having a groove
28
and a via contact hole
26
lying below the groove
28
. Subsequently, tungsten is deposited, by the use of the sputtering method, to form a tungsten layer
72
over the whole surface of the semiconductor substrate
12
having the structure processed as mentioned above, whereby the groove
28
and the via contact hole
26
are filled up with the tungsten as shown in
FIG. 37
(Step
4
). Then, the portion of the tungsten lying on the upper surface of the inter-layered insulation film
24
is removed by a CMP treatment, whereby a second metal wiring layer
74
composed of tungsten is formed in the groove and the via contact hole as shown in
FIG. 38
(Step
5
). Next, as shown in
FIG. 39
, over the whole surface of the semiconductor substrate
12
having the structure processed as mentioned above, a second inter-layered insulation film
48
is formed by the use of the CVD method (Step
6
).
As may be apparent from the foregoing description concerning the RIE method and the damascene method, the number of manufacturing steps is smaller in the case of the damascene method than in the case of the RIE method. Further, the damascenene method is suited for the formation of fine metal patterns, too. As stated above, the damascenene method is superior in many points to the RIE method, but the damascene method has the following defects:
That is, in case the dual damscene groove and the via contact hole are to be filled up with aluminum, the bottom portion of the via contact hole which has a high aspect ratio (height/width ratio) can hardly be filled up since the reflowability of the aluminum is not so high. If the temperature at the time of depositing the aluminum is enhanced, then the reflowability of the aluminum is increased, but, if the temperature is made too high, then the aluminum will become round due to its surface tension. That is, it is difficult to obtain a via contact filling having a high aspect ratio by the use of aluminum. On the other hand, tungsten has a high reflowability and therefore can fill up even the bottom portion of the via contact hole having a high aspect ratio, but the wiring resistance of tungsten is high.
As described above, in the case of the conventional dual damascene type via contact wiring structure, if the via contact hole is to be filled up with aluminum, it is difficult to fill up the via contact hole, which has a high aspect ratio, as far as its bottom portion. On the other hand, in case the via contact hole is filled up with tungsten, the wiring resistance becomes high. Due to this, the conventional dual damascene formation method is not applicable to the formation of a multi-layer wiring structure.
As described above, in the formation of the conventional dual damascene type via contact structure, it is difficult to fill up the via contact hole which has a high aspect ratio as far as its bottom portion by the use of the metal material due to the lowness in reflowability of the metal. Further, tungsten is used as the metal material, the wiring resistance become high, which is quite a problem.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in view of these circumstances, and it is the object of the invention to provide a semiconductor device with a dual damascene type via contact structure which is constituted in such a manner that the via contact hole having a high aspect ratio can be filled up as far as its bottom portion with the metal material, and the conventional problem or defect that, due to the high-temperature heat treatment performed at the time of depositing a metal material for the formation of the second metal wiring, the first metal wiring layer is melted is eliminated, so that the application of the dual damascene type via contact structure to a multi-layer wiring structure becomes possible.
In order to achieve the object mentioned above, a semiconductor device with a dual damascene type via contact structure according to the present invention comprises a first metal wiring formed on a semiconductor substrate; an inter-layered insulation film formed on the semiconductor substrate including the first metal wiring; a dual damascene structure having a groove and a via contact hole which are formed in the inter-layered insulation film and lead to the first metal wiring; a via contact filling layer formed by filling up, with a metal material, the interior of the via contact hol

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