JPH02237026A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce junction leakage current, contact resistance and sheet resistance by a method wherein a high melting point metallic silicide film is irradiated with specific laser beams in an atmosphere containing N to form a high melting point nitride film. CONSTITUTION:The surface of an interlayer insulating film 10 excluding the parts of contact holes C1 to C3 is covered with a reflection film 11 and then the whole surface is irradiated with laser beams B in an atmosphere containing N so that only TiSi2 films 9a to 9c inside these contact holes C1 to C3 may be locally heated at high temperature. Accordingly, TiN films 13a to 13c can be formed in self-alignment with these contact holes C1 to C3 on the TiSi2 films 9a to 9c. In this case, the parts not irradiated with the laser beams B are not heated at high temperature so that the surface of the TiSi2 films 9a to 9c on the parts not nitrified may not be subjected to the deterioration in morphology even if any hillock is formed on the surface. Through these procedures, contact resistance, sheet resistance and leakage current can be kept small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and more specifically, to a method for manufacturing a semiconductor device. The present invention relates to a method of manufacturing a semiconductor device having a layered film.

[Summary of the Invention] The present invention provides a method for manufacturing a semiconductor device having a high melting point metal silicide film and a high melting point metal nitride film formed on the high melting point metal silicide film. In this method, the high melting point metal nitride film is formed by selectively irradiating the high melting point metal silicide film with a laser beam having an energy density of 1400 to 220 Q m J/cm', thereby reducing junction leakage. It is designed to reduce current, contact resistance, and sheet resistance.

[Prior Art] In a semiconductor device, aluminum (A1) wiring contacts a diffusion layer formed in a semiconductor substrate through a contact hole formed in an interlayer insulating film.

Conventionally, in order to reduce the sheet resistance of this diffusion layer and prevent the reaction between AI wiring and this diffusion layer, for example, a titanium silicide (TiSt) film and a titanium nitride (TiN) WJ formed thereon have been used. A technique is known in which an AI wiring is brought into contact with a diffusion layer through a two-layered film.

JP-A-62-169412 describes this Tisiz
As a method of forming a TiN film on a film, TiN film is formed on a diffusion layer.
After forming the Si* film, annealing is performed at a high temperature of 900°C or higher in an atmosphere containing nitrogen (N) to remove this Ti film.
A method of forming a TiN film by nitriding the surface of the Si film is disclosed.

[Problems to be Solved by the Invention] However, in the method disclosed in the above-mentioned Japanese Patent Application Laid-open No. 1694-12-1983, the entire semiconductor substrate is heated to a high temperature of 900° C. or higher, and therefore, it is not nitrided. The morphology of the surface of the TiSi film in the part
There was a problem in that the electrical characteristics deteriorated as a result of the deterioration of the electrical characteristics. In addition, in particular, as the depth dimension (X,) of the source/drain region has become shallower with the miniaturization of devices in recent years, the entire semiconductor substrate is heated to high temperatures, causing There was also the problem that impurity re-diffusion occurred and the diffusion layer expanded.

The present invention was devised by focusing on such conventional problems, and it is possible to convert a high melting point metal nitride film to a high melting point without causing deterioration of the morphology of the high melting point metal silicide film or re-diffusion of impurities. The present invention aims to provide a method for manufacturing a semiconductor device that can be formed on a metal silicide film and that can reduce junction leakage current, contact resistance, and sheet resistance.

[Means for Solving the Problems] Therefore, the present invention provides a method for manufacturing a semiconductor device having a high melting point metal silicide film and a high melting point metal nitride film formed on the high melting point metal silicide film. (nitrogen)
The high melting point metal silicide film has an energy density of 1400 to 2200 mJ/c in an atmosphere containing
The solution is to form the high melting point metal nitride film by selectively irradiating the laser beam with m-thickness.

[Operation] By selectively irradiating the laser beam in an atmosphere containing N, only the part of the high melting point metal silicide film to be nitrided is locally heated to a high temperature, and the high melting point metal nitride film is formed in this part. is formed, but other parts are not heated to high temperatures. Therefore, it is possible to prevent deterioration of the morphology of the surface of the high melting point metal silicide film and re-diffusion of impurities in the portions where this nitridation is not performed. In addition, the energy density of the laser beam was increased to 1400
By setting the resistance to ~2200 mJ/cm, it is possible to keep contact resistance, sheet resistance, and leakage current low.

[Example] Hereinafter, details of a method for manufacturing a semiconductor device according to the present invention will be described based on an example shown in the drawings. This example is an example in which the present invention is applied to manufacturing a MOS transistor.

FIGS. 1A to 1I are cross-sectional views showing the steps of the manufacturing method of this embodiment.

In this embodiment, as shown in FIG.
For example, S is applied to the surface of the semiconductor substrate 1, which is a type of silicon substrate.
After selectively forming a field insulating film 2 such as an iO, film to perform element isolation, the surface of the active region surrounded by this field insulating film 2 is coated with, for example, Si by thermal oxidation.
O! A film-like gate insulator MJ3 is formed. Next, a polycrystalline Si film doped with impurities, for example, is formed on the gate insulating film 3, and then the polycrystalline Si film and the gate insulating film 3 are patterned into a predetermined shape by etching. As a result, gate electrode 4 is formed. Thereafter, using the gate electrode 4 as a mask, an n-type impurity such as phosphorus (P) is ion-implanted into the semiconductor substrate 1 at a low concentration. Next, the entire surface is coated with, for example, Si by, for example, CVD.
O, after forming the film, for example, reactive ion etching (
RlE), this Sin. The film is anisotropically etched in a direction perpendicular to the substrate surface to form sidewalls (sidewall spacers) 5 made of Sin. Next, using this side wall 5 as a mask, an n-type impurity such as arsenic (As) is ion-implanted into the semiconductor substrate 1 at a relatively high concentration. As a result, for example, an n0 type source region 6 and drain region 7 are formed in a self-aligned manner with respect to the gate electrode 4. These gate electrode 4, source region 6 and drain region 7
Thus, an n-channel MOSFET is configured.

These source regions 6 and drain regions 7 are provided with low impurity concentration regions 6a, 7a of n-type, for example, in the lower part of the sidewall 5.
Therefore, this n-channel MOSFET has a so-called LDD (Lightl
y Doped Drain) structure. Note that this n-channel MOSFET does not necessarily have to have an LDD structure. After this, by annealing ζ,
The ion-implanted impurities are electrically activated.

Next, as shown in FIG. 1B, a titanium (Ti) film 8 is formed on the entire surface by, for example, sputtering or vapor deposition.

Next, by performing annealing at a temperature of about 800° C., for example, the Ti film 8 is reacted with the gate electrode 4, source region 6, and drain region 7 with which the Ti film 8 is in direct contact. As a result, the surfaces of gate electrode 4, source region 6, and drain region 7 are silicided.

Thereafter, the unreacted Ti film 8 is removed by etching. In this way, as shown in FIG.
i. Films 9a-9C are formed. These TiSi. The thickness of the films 9a to 9C is, for example, about 1000. These TiSi. The films 9a to 9C can reduce the sheet resistance of the gate electrode 4, source region 6, and drain region 7.

Note that the above-mentioned annealing can also be performed by, for example, infrared (IR) annealing.

Next, as shown in FIG. 1D, an interlayer insulating film 10 such as a phosphosilicate glass (PSG) film is formed on the entire surface by, for example, CVD, and then an interlayer insulating film 10 such as a phosphosilicate glass (PSG) film is formed on the interlayer insulating film 10 by, for example, sputtering or vapor deposition. After forming a reflective film l1 such as an AI film for the laser beam B, which will be described later, a resist pattern l2 of a predetermined shape is formed on the reflective film 11 by lithography.

Next, using the resist pattern 12 as a mask, predetermined portions of the reflective film 1 and the interlayer insulating film 10 are etched by, for example, RIE to form contact holes C, -C and the like, as shown in FIG. 1E. form.

After this, the resist pattern 12 is removed.

Next, as shown in FIG. 1F, an atmosphere containing N, for example, N
, gas or ammonia (NHs) gas (70QmT
orr) to irradiate the entire surface with laser beam B. As this laser beam B, for example, a pulsed laser beam (
Waves & 308 nm) can be used. In this case, the irradiation energy density of laser beam B is 140
Set to 0~2200mJ/cm''.And,
Since the laser beam B incident on the reflective film l1 is reflected, the contact holes C, -C. Only the internal T + S r * films 9a to 9c are irradiated with laser beam B.
By irradiating Ti inside contact holes CI to C3,
Only the Si films 9a to 9c are locally heated to a high temperature, and this portion is nitrided to a predetermined depth by N in the atmospheric gas decomposed by the laser beam B irradiation. As a result, the TiN films 13a to 13c are connected to the contact hole C1.
~C3 is formed in a self-aligned manner. These Ti
By the N films 13a to 13c, wirings 14a to 14, which will be described later, are connected.
Reactions between C and the gate electrode 4, source region 6, and drain region 7 can be prevented. Note that in order to effectively prevent this reaction, these TiN films 13a to 13
The thickness of c is preferably about 500 or more, for example.

Next, for example, the entire surface is coated by sputtering or vapor deposition. A
After forming the J film, this AI film is patterned into a predetermined shape by etching to form the 11th! ! Wires 148 to 14c are formed as shown in aH, thereby completing the desired MOSLSI.

As described above, according to this embodiment, the surface of the interlayer insulating film 10 except for the contact holes C and C3 is covered with the reflective film 11, and in this state, the laser beam B is irradiated in an atmosphere containing N. These contact holes C. ~C, TiSi. Membranes 9a-9
Since only C.C is locally heated to a high temperature, these contact holes C. ~C. These contact holes C1 to C3 are formed on the TiSit films 9a to 9c inside the
The TiN films 13a to 13C can be formed in a self-aligned manner. In this case, since the portions that are not irradiated with the laser beam B are not heated to a high temperature, hillocks may be formed on the surfaces of the TiSi films 9a to 9c in the portions where nitridation is not performed, resulting in deterioration of morphology. Therefore, no deterioration of electrical characteristics occurs. Furthermore, source region 6 and drain region 7
Since re-diffusion of impurities therein does not occur, these source regions 6 and drain regions 7 do not spread.

In addition, FIGS. 2 and 3 show the contact resistance and sheet resistance measured when the energy density of the excimer laser irradiated to a TiSi* film with a thickness of 600 to 700 people was varied by the method in the above example. It is a graph showing the results. Note that the arrows shown in both figures indicate values when the excimer laser is not irradiated. Moreover, FIG. 4 is a graph showing the results of measuring leakage current in a p-type MOS transistor by changing the energy density of the excimer laser according to the above embodiment. Note that the arrows in the figure indicate values when the excimer laser is not irradiated.

As these graphs show, it can be seen that the laser irradiation conditions have a large effect on the contact resistance, sheet resistance, and leakage current. For example, when the energy density of the excimer laser exceeds 3000 mJ, the resistance value becomes extremely high, and at 80 QmJ, the leakage level becomes the same as when no excimer laser is used (~1000 mJ).
nA).

Furthermore, it can be seen that the contact resistance, sheet resistance, and leakage current are kept low in the range of 1400 mJ to 2200 mJ.

Next, FIG. 5 shows another embodiment according to the present invention.

In this example, after the step shown in FIG. 1E of the above-mentioned example, S
For example, an amorphous layer (indicated by an X mark in the figure) is formed on the surface of TiSi by performing an amorphous process at an output of 20 K e V, for example.

Next, a step corresponding to FIG. 1F of the above-described embodiment is performed to form a TiSi. The amorphous layer on the surface is changed to a TiN film. Note that in this step, the excimer laser irradiation may be performed by pulse shot processing. Also,
In addition to Si°, the ions to be implanted include Ti° and N°. etc. may also be used.

In this example, since the formed amorphous layer has a low melting point, it is possible to improve energy efficiency. Moreover, TiSi. Ion implantation may be performed on the Si substrate instead of ion implantation on the surface. In this example, a contact hole with a particularly small diameter (0.35μ
It is effective when applied to the following processes. Furthermore, since the melting point of the amorphous layer is lowered, there is an advantage that the area of the laser beam can be increased and the size of the laser device can be reduced.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the present invention.

For example, in both of the above embodiments, T is used as the high melting point metal.
i was used, but tungsten (W), molybdenum (MO
) etc. are applied.

Further, in the above embodiment, the reflective film l1 is left in the final structure, but this reflective film l1 is, for example, the wiring 14 to 14.
It is also possible to perform etching removal using, for example, phosphoric acid before forming c. Moreover, as this reflective film l1,
For example, it is also possible to use a barrier metal film such as a Ti film. Furthermore, even if another metal film that absorbs the laser beam B is used instead of the reflective film l1, the TiSi,1
It is possible to selectively irradiate only 1Q9a to 9C with the laser beam B.

Furthermore, in the above-mentioned embodiments, the case where the present invention is applied to a MOS transistor was explained, but the present invention
For example, it is also possible to apply the present invention to the manufacture of semiconductor integrated circuit devices other than MOSLSI, such as bipolar LSI and bipolar CMOS LSI.

[Effects of the Invention] As described above, according to the present invention, a high melting point metal nitride film is formed by selectively irradiating a high melting point metal silicide film with a laser beam in an atmosphere containing nitrogen. Therefore, the portions that are not irradiated with the laser beam are not heated to a high temperature, and therefore, it is possible to prevent deterioration of the morphology of the surface of the high melting point metal silicide film and re-diffusion of impurities.

Further, according to the present invention, there is an effect that contact resistance, sheet resistance, and leakage current can be kept low.

[Brief explanation of drawings]

Figures 1A to 1H are cross-sectional views showing step-by-step a method for manufacturing a MoS transistor according to an embodiment of the present invention, Figure 2 is a graph showing the relationship between excimer laser energy density and contact resistance, and Figure 3 is a graph showing the relationship between excimer laser energy density and contact resistance. 4 is a graph showing the relationship between the energy density and sheet resistance of the excimer laser, FIG. 4 is a graph showing the relationship between the energy density of the excimer laser and leakage current, and FIG. 5 is a cross-sectional view showing another embodiment of the present invention. be. l...Semiconductor substrate, 2...Field insulating film, 4...
. . . Gate electrode, 6. Source region, 7. Drain region, 8. Ti film, 9 a to 9 c-.-Ti
S i , film, 11... reflective film, 13a-l3c-T
i N film, 14~14C... wiring, 01~C,...
・Contact hole. Example Fig. 1 A Example Fig. 1 B Fig. 1 D Actual Example B Laser and $12 - Example Fig. 1 F Fig. 1 G Example Fig. 1 H Energy (mj) of excimer laser Graph showing energy density and leakage current Figure 4 Other 1j examples Figure 5

Claims (1)

[Claims] (1) In a method for manufacturing a semiconductor device having a high melting point metal silicide film and a high melting point metal nitride film formed on the high melting point metal silicide film, the high melting point metal is In the silicide film, the energy density is 1
A method for manufacturing a semiconductor device, characterized in that the high melting point metal nitride film is formed by selectively irradiating a laser beam of 400 to 2200 mJ/cm^2.