JPH10294369A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve (111) orientation of an Al film regardless of process conditions at the time of wiring formation by applying SOG(spin on glass) to a BPSG film for increasing the supply of atoms of hydrogen onto the surface of the BPSG film. SOLUTION: An SOG film 30 is formed on a BPSG film 20 formed on a semiconductor substrate. A contact hole or a via hole penetrating the BPSG film 20 and the SOG film 30 is formed. A barrier film 40 including a Ti layer is formed on the SOG film 30. An Al film 50 containing impurities is formed on the barrier film 40. Atoms of hydrogen are supplied from the SOG film 30 on the BPSG film 20 to the surface of the BPSG film 20 for increasing the throughput. The (002) orientation of Ti of the barrier film 40 is improved for improving the (111) orientation of the Al based film regardless of process conditions at the time of wiring formation. In this way, the resistance to electromigration is increased and the life of wiring is improved.

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 a method for manufacturing the same, and more particularly, to an improvement in the wiring life of Al-based wiring.

[0002]

2. Description of the Related Art With the miniaturization of elements accompanying the recent high integration of semiconductor devices, the current density flowing through wirings has been increased, so that problems such as disconnection have increased.
ro migration) It is necessary to improve resistance. The EM is a phenomenon in which a metal ion is moved by an electron to generate a void, which eventually leads to disconnection.

Therefore, a method of improving the orientation of the (111) crystal orientation of Al has been conventionally studied as one of the methods for improving the EM resistance of the wiring. One study example is Al
The (111) orientation of the film reflects the (002) orientation of the underlying layer Ti, and the Ti crystal orientation is BPSG (borophosphosi
It has been reported that the concentration can be improved by increasing the concentration of hydrogen atoms near the surface of the (licate glass) film (8p-N-7, 1996 Autumn Meeting of the Japan Society of Applied Physics).

[0004] Specifically, a BPSG film containing a high concentration of B is formed and left in the air for a long time to increase the concentration of hydrogen atoms near the surface of the BPSG film. In order to enhance the reliability of the contact hole, a process of providing a barrier metal under the Al layer is generally performed.

As a structure of the barrier metal, a Ti layer used for securing the ohmic property of the contact and a TiN layer used for securing the barrier property are generally laminated. Furthermore, it is known that the orientation of these barrier metals affects the orientation of Al.

FIG. 4 is a cross-sectional view showing a schematic configuration of a semiconductor device conventionally proposed for the purpose of improving the orientation of Al wiring. An example of a conventional method for manufacturing a semiconductor device will be described with reference to FIG. In FIG. 4, an interlayer insulating film 80 of a silicon oxide (SiO ₂ ) film is formed on a silicon substrate 10, and a contact hole is formed in the interlayer insulating film 80.

[0007] The wafer having the contact hole is opened.
RF bias application type ECR (electron cyclotron resonanc)
e) Set in a plasma CVD (chemical vapor deposition) apparatus, and form a CVD-Ti film 90 under specific conditions by using TiCl ₄ and H ₂ as source gases at 2 to 10 nm. Here, by applying an RF bias voltage, the incident angle distribution of Ti particles is suppressed, and a CVD-Ti film 90 having a (002) orientation is formed.

Next, a discharge is performed under specific conditions in which TiCl ₄ , H ₂ , N ₂ and Ar are introduced, and the CVD-TiN film 100 having (111) orientation
To form Then, the Ti film 70 using a sputtering method
And an Al-1% Si film 110. The conventional method for manufacturing a semiconductor device is described in Japanese Patent Application Laid-Open No. 7-41949.

[0009]

In the above conventional example, since a BPSG film containing a high concentration of B is grown and left in the air for a long time, there is a problem that the throughput is low. Another conventional example examines in detail the device structure such as sputtering and CVD used for forming the wiring including the barrier metal, or the process conditions, in order to achieve the improvement of the orientation of the Al-based wiring, It needed to be optimized.
However, there are various parameters in the process conditions,
Since these parameters affect not only the orientation but also the adhesion of the film, the resistance value, and the like, there is a problem that the operation is very difficult.

[0010] Accordingly, the present invention provides a method of forming SOG (spin
By increasing the supply of hydrogen atoms to the BPSG film surface by forming an (on glass) film, the throughput is high, and the (111) orientation of the Al film is improved regardless of the process conditions when forming wiring. With the goal.

[0011]

According to the present invention, there is provided a semiconductor device comprising:
An insulating film formed on the semiconductor substrate; an SOG film formed on the insulating film; an opening reaching the semiconductor substrate formed on the insulating film and the SOG film; and an opening on the SOG film and the opening. It is characterized by having a barrier metal film formed in the hole and an Al film containing impurities formed on the barrier metal film.

Further, a method of manufacturing a semiconductor device according to the present invention
Forming an insulating film and an SOG film sequentially on the semiconductor substrate;
Forming an opening in the insulating film and the SOG film reaching the semiconductor substrate, forming a barrier metal film on the SOG film and in the opening, and including an impurity on the barrier metal film. Forming an Al film.

[0013]

According to the present invention, hydrogen atoms are supplied from the SOG film on the BPSG film to the surface of the BPSG film.
2) The orientation is improved, and the (111) orientation of the Al-based film on Ti can be improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1E is a schematic longitudinal sectional view showing an Al-based wiring structure according to the first embodiment of the present invention.
Next, the manufacturing process of the Al-based wiring structure shown in FIG.
(A) to (e) will be specifically described. FIG. 1 (a)
As shown in the figure, on a silicon (Si) substrate 10, as an insulating film
In order to form an oxide film containing impurities such as BPSG or PSG, the BPSG film 20 is formed using, for example, a normal pressure CVD method.

Next, as shown in FIG.
The SOG film 30 is formed using a heater and annealing is performed. here,
As shown in FIG. 1C, a resist (not shown) is applied, and a contact hole or a via hole is formed by using a photolithography technique. Thereafter, as shown in FIG. 1 (d), for example, a Ti film 40 is formed by collimated sputtering.
To form

Next, as shown in FIG. 1E, an Al film 50 containing impurities is formed by a usual sputtering method. The Al film 50 is made of Al-Si-Cu containing Si and Cu as impurities,
Alternatively, Al-Si or Al-Cu is used. The wiring formed in this manner is changed from the SOG film 30 on the BPSG film 20 to the BPSG film.
20 Since hydrogen atoms are supplied to the surface, the Ti film 40
(002) orientation is improved. Therefore, since the (111) orientation of the Al-based film 50 on the Ti film 40 is improved, electromigration is performed.
And the service life of the wiring can be improved.

Next, a second embodiment of the present invention will be specifically described with reference to the drawings. FIG. 2B is a schematic vertical sectional view showing an Al-based wiring structure according to a second embodiment of the present invention. The manufacturing process of the Al-based wiring structure shown in FIG. 2B will be specifically described based on FIGS. 1A to 1D and FIG.

Also in this second embodiment, FIG.
Steps (d) to (d) are performed in the same manner as in the first embodiment. And
After forming the Ti film 40 of the barrier film shown in FIG. 1D, a TiN film 60 is formed on the Ti film 40 as shown in FIG. Improve sexuality.

(002) TiN film on Ti film 40 with improved orientation
The Al-based film 50 formed on the (111) -oriented TiN film 60 has a (111) -oriented TiN film 60 and a (111) -oriented Al having a lattice constant close to that of the (111) -oriented TiN film 60. Orient. Therefore, TiN film 60
Even if the barrier property is improved by forming the same, a structure similar to the structure shown in the first embodiment can be obtained, and the electromigration resistance is improved and the wiring life is improved as in the first embodiment. The effect to be obtained is obtained.

Next, a third embodiment of the present invention will be specifically described with reference to the drawings. FIG. 3B is a schematic vertical sectional view showing an Al-based wiring structure according to the third embodiment of the present invention. The manufacturing process of the Al-based wiring structure shown in FIG. 3B will be specifically described with reference to FIGS. 1A to 1D and FIGS. 2A and 3A. Also in the third embodiment, the steps of FIGS. 1A to 1D are performed in the same manner as in the first embodiment.

Subsequently, after the TiN film 60 of the second embodiment shown in FIG. 2A is formed, a Ti film 70 is further formed on the TiN film 60 as shown in FIG. And on top of that Al
The film 50 is formed to have a laminated structure of Ti / TiN / Ti. (002) Oriented Ti film 40, Ti film 70, (111) oriented TiN film 60 and (111)
Since the oriented Al-based film 50 has a lattice constant close to each other, even if the barrier film is laminated to lower the resistance and the adhesion and barrier property of the film are improved, the structure is the same as the structure shown in the first embodiment. As in the first and second embodiments, the effect of improving the electromigration resistance and the life of the wiring can be obtained.

[0022]

As described above, according to the present invention, SOG on BPSG film
Since hydrogen atoms are supplied from the membrane to the BPSG membrane surface,
The put is high, and the (002) orientation of Ti in the barrier film is improved regardless of the process conditions at the time of forming the wiring. Therefore, since the (111) orientation of the Al-based film on Ti is improved, the electromigration resistance is improved, and the life of the wiring is improved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a semiconductor device according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a schematic longitudinal sectional view of a semiconductor device in a process order according to a second embodiment of the present invention.

FIG. 3 is a schematic vertical sectional view of a semiconductor device according to a third embodiment of the present invention in the order of steps.

FIG. 4 is a schematic longitudinal sectional view of a conventional semiconductor device.

[Explanation of symbols]

10 Silicon (Si) substrate 20 BPSG film 30 SOG film 40 Ti film 50 Al-based film 60 TiN film 70 Ti film 80 Interlayer insulating film of SiO ₂ film 90 CVD-Ti film 100 CVD-TiN film 110 Al-1% Si film

Claims (5)

[Claims] An insulating film formed on the semiconductor substrate; an SOG film formed on the insulating film; an opening reaching the semiconductor substrate formed on the insulating film and the SOG film; A barrier metal film formed on the film and in the opening, and an Al containing impurity formed on the barrier metal film
And a film. 2. The semiconductor device according to claim 1, wherein the insulating film is a BPSG film or a PSG film. 3. The barrier metal film is formed of Ti, Ti / TiN or
2. The semiconductor device according to claim 1, wherein the ratio is Ti / TiN / Ti. 4. The Al film is made of Al-Si, Al-Si-Cu or Al-C.
The semiconductor device according to claim 1, wherein u. 5. A step of sequentially forming an insulating film and an SOG film on a semiconductor substrate; a step of forming an opening reaching the semiconductor substrate in the insulating film and the SOG film; and forming an opening on the SOG film and the opening. A method of manufacturing a semiconductor device, comprising: forming a barrier metal film therein; and forming an Al film containing impurities on the barrier metal film.