KR980011910A - Method of forming silicide - Google Patents

Abstract

The present invention describes a method for forming a co-side by salicide. The method includes forming a gate electrode and a low concentration source / drain region on a silicon substrate, forming a spacer on a side surface of the gate electrode, depositing a refractory metal to a predetermined thickness on the entire surface of the resultant structure, Forming a source / drain region and a silicide layer on the entire surface of the resultant metal layer by scanning a laser beam under a doping gas atmosphere. Therefore, according to the present invention, in order to suppress the short channel effect and the punch through phenomenon caused by the increase in the degree of integration of semiconductor devices, the laser beam is scanned by decreasing the junction depth so as to reduce the increased sheet resistance, So as to prevent the short-circuit phenomenon, thereby improving the performance and reliability of the semiconductor device.

Description

Implementation Side Formation Method

The present invention relates to a method for forming an upper portion of a gate electrode into a low resistance salicide, and more particularly to a method for forming a silicide by scanning a laser beam with a metal.

Generally, as the degree of integration of a semiconductor device increases, the number of discrete elements having a relatively small size increases, so that the length of metal interconnection lines for electrically connecting the plurality of discrete elements increases relatively, while the line width decreases The thickness also decreases. Therefore, the signal transmission time is delayed due to an increase in the sheet resistance of the metal wiring in the integrated circuit, especially in the gate wiring and the source / drain region, or the contact resistance is increased as the contact area is reduced.

As described above, in order to solve the problem of increased sheet resistance and contact resistance of the metal wiring due to increase in integration degree of the semiconductor device, the material used for the metal wiring is formed of a combination of silicon and high melting point metal such as titanium, tantalum, or tungsten A method of replacing the silicide with a silicide is proposed. At this time, these silicides are widely used in a salicide (self ailgned silicide) process for wiring in an integrated circuit of a semiconductor device. The salicide process may be performed by depositing a refractory metal on the gate electrode formed on the silicon substrate and the silicon constituting the source region / drain region, forming a silicide by chemical reaction between the silicon and the refractory metal under a high temperature atmosphere Process.

1 to 3, a method of forming a silicide according to the related art includes a step of forming a transistor including a gate electrode 120 and a source / drain region S / D on a silicon substrate 110 Forming a spacer layer on a side surface of the gate electrode; depositing a refractory metal on the entire surface of the resultant to form a metal layer; annealing in a high temperature atmosphere; Forming a silicide 140 by a silicidation reaction with the metal layer, and removing a portion of the metal layer that remains.

However, according to the conventional embodiment, the step of forming the drain region / the source region by the impurity ion implantation step and the step of forming the silicide by the silicide are performed separately. Accordingly, during the annealing under a high-temperature atmosphere, a diffusion phenomenon occurs in which a part of the silicon atoms constituting the silicon substrate 110 and the gate electrode 120 moves to the spacer 121. That is, due to the diffusion of the silicon atoms, an undesirable silicide of a refractory metal is formed in the spacer 121, and electrical short-circuit phenomenon occurs between the gate electrode and the source / drain regions due to the silicide, Resulting in deterioration of performance.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method of manufacturing a semiconductor device, Provided is a method of forming a silicide capable of improving the performance and reliability of a semiconductor device by preventing the formation of silicide in the gate spacer when forming the silicide to reduce the sheet resistance.

Brief Description of Drawings

FIGS. 1 to 3 are cross-sectional views sequentially illustrating a method of forming a silicide according to a conventional example

FIGS. 4 to 6 are cross-sectional views sequentially illustrating a method for forming a silicide according to the present invention

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: forming a gate electrode and a lightly doped source / drain region on a silicon substrate; Forming a spacer on a side surface of the gate electrode; Depositing a refractory metal to a predetermined thickness on the entire surface of the resultant to form a metal layer; And a step of forming a source / drain region and a silicide of high concentration by scanning a laser beam on the entire surface of the resultant of the formation of the metal layer under an atmosphere of a doping gas.

According to a preferred embodiment of the present invention, the refractory metal is made of titanium or cobalt.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 4 to 6 are cross-sectional views sequentially illustrating a method of forming a silicide according to an embodiment of the present invention.

That is, the method of forming a silicide according to an embodiment of the present invention includes the steps of forming a gate electrode 220 and a lightly doped source / drain region on a silicon substrate 210, Forming a metal layer 230 on the entire surface of the resultant by depositing a refractory metal to a predetermined thickness on the entire surface of the resultant product; And forming a heavily doped source / drain region (S / D) and a silicide layer 240 by scanning the beam.

Referring to FIG. 4, which is a cross-sectional view illustrating a metal layer formed on a resultant silicon substrate having a transistor having a gate electrode, the silicon substrate 210 is thermally oxidized to have a thickness of about 100 to 300 A pad oxide film (not shown) is formed. Silicon nitride is deposited on the pad oxide film to a predetermined thickness by a chemical vapor deposition process or the like to form a nitride layer (not shown). Thereafter, a part of the silicon substrate 210 is exposed using a mast having a predetermined line-width size formed by a photolithography process or the like.

At this time, a part of the silicon substrate 210 exposed through the pattern of the nitride layer and the pad oxide film is partially etched by a field oxide film having a predetermined line-width size (for example, (Not shown) to define the active region on the silicon substrate 210.

A gate insulating layer 211 made of an oxide film formed by a thermal oxidation process and a conductive layer for a gate electrode made of silicon doped with impurities such as polysilicon are sequentially formed on the active region on the silicon substrate 210 . A part of the conductive layer for the gate electrode and a part of the gate insulating film 211 are removed by a dry etching process or the like using a mask formed by a photolithography process. Thus, the gate electrode 220 having a predetermined line width size is formed on the gate insulating film 211 as a result of the etching process.

Thereafter, by implanting phosohorus or BF2 into the silicon substrate 210 exposed through the pattern by an ion implantation process using the pattern of the gate electrode 220 as an ion implantation mask, a low concentration (LDD) source region / Drain regions. As described above, an insulating layer (not shown) is formed by depositing silicon nitride or silicon oxide to a predetermined thickness on the entire surface of the resultant substrate in which the low concentration source / drain regions are formed by a chemical vapor deposition (CVD) process or the like, A portion of the insulating layer is removed by a dry etching process having a favorable anisotropic etching property such as an etch (RIE) process, and spacers 221 remaining at a predetermined line-width size are formed on the side surface of the gate electrode 220.

Thereafter, a refractory metal is deposited to a predetermined thickness on the entire surface of the resultant structure on which the spacer 221 is formed by a sputtering process or a plasma deposition process to form the metal layer 230. Here, the refractory metal constituting the metal layer 230 is made of titanium or cobalt.

Referring to FIG. 5, which is a cross-sectional view illustrating scanning of a laser beam on the resultant of the metal layer 230, the resultant with the metal layer 230 is charged into a chamber in which a doping atmosphere is formed by the gas to be doped. At this time, the chamber introduces the reactive gases as described above to be held under a pressure of about 1 to 100 Torr. Meanwhile, an excimer laser beam obtained from ArF, KrF, or XeCl gas is injected into a semiconductor substrate mounted in the chamber through a lens while introducing reactive gases into the chamber, and as a result, the refractory metal Silicon constituting the gate electrode 220 and the silicon substrate 210 is instantaneously melted for a short time (nano seconds) by the energy of the injected laser beam. Thereafter, a silicidation reaction is performed in which the silicide 240 is formed by mutual diffusion of molten high melting point metal atoms and silicon atoms in the course of performing recrystallization growth of the molten material. Meanwhile, according to a preferred embodiment of the present invention, the silicide 240 formed by the silicidation reaction is made of titanium silicide (TiSi ₂ ) or cobalt silicide (CoS ₂ i).

On the other hand, the reactive gases leading to the atmosphere in the chamber are composed of a Group V source compound or a Group III element compound and preferably composed of at least one element of PH ₃ , AsH ₃ , B ₂ H ₆ , BF ₃ and BCl ₃ have. Therefore, the silicon substrate 210, which is exposed through the pattern of the spacers 221, is doped with the reactive gas and diffused to form the silicide 240 having a predetermined pattern by the scanning of the laser beam, / Drain < / RTI > region S / D, resulting in a thin junction region.

6, which is a cross-sectional view showing that the metal layer remaining on the silicon substrate after the laser beam scanning is removed, A portion of the metal layer 230 is removed by a sulfuric acid (H ₂ SO ₄ ) solution. A portion of the silicide 240 remaining on the gate electrode 220 and the high concentration source / drain region S / D is left on the silicon substrate 210.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined by the appended claims. .

Therefore, according to the present invention, in order to suppress a short channel effect and a punch through phenomenon caused by an increase in the degree of integration of a semiconductor device, a method of forming a silicide so as to reduce an increased surface resistance, A laser beam is scanned on a metal layer made of a melting point metal to prevent the short-circuit phenomenon, thereby improving the performance and reliability of the semiconductor device.

Claims (4)

Forming a gate electrode and a lightly doped source / drain region on the silicon substrate; Forming a spacer on a side surface of the gate electrode; Depositing a refractory metal to a predetermined thickness on the entire surface of the resultant to form a metal layer; And a step of forming a source / drain region and a silicide layer 240 by implanting a laser beam onto the entire surface of the resultant structure having the metal layer in a doping gas atmosphere. The method of claim 1, wherein the metal layer comprises titanium or cobalt. The method of forming a silicide according to claim 2, wherein the doping gas atmosphere is composed of a Group V element compound or a Group III element compound. The method according to claim 3, wherein the doping gas atmosphere comprises at least one element selected from the group consisting of PH ₃ , AsH ₃ , B ₂ H ₆ , BF ₃ and BCl ₃ . ※ Note: It is disclosed by the contents of the first application.