KR20040055868A - Method of manufacturing semiconductor device Using salicide process - Google Patents

Abstract

PURPOSE: A method for fabricating a semiconductor device by a silicide process is provided to prevent a gate electrode and a source/drain region from being short-circuited by preventing conductive residue from being generated by a silicide process. CONSTITUTION: A gate electrode(34), a source region(40) and a drain region(38) are formed on a semiconductor substrate(30). After the first refractory metal layer is formed on the gate electrode, a heat treatment process is performed to form the first refractory metal silicide layer. An interlayer dielectric(44) is formed on the resultant structure. A contact hole penetrates the interlayer dielectric to expose the source region and the drain region. After the second refractory metal layer is formed only on the bottom of the inside of the contact hole of the exposed source/drain region, a heat treatment process is performed to form the second refractory metal silicide layer. A contact hole penetrates the interlayer dielectric to expose the gate electrode. A conductive material is filled in the contact holes that expose the source or drain region and the gate electrode so that a source/drain contact(DC) and a gate contact(GC) are formed.

Description

Method of manufacturing semiconductor device using silicide process {Method of manufacturing semiconductor device Using salicide process}

The present invention relates to a method for manufacturing a semiconductor device in which a silicide process is used.

As semiconductor devices are highly integrated, devices that require fast operating speeds are continuously developed. In particular, in the process of manufacturing a device that requires a fast operating speed, such as SRAM (SRAM) or logic device (silicon), in order to reduce the sheet resistance and contact resistance of the gate electrode and the source / drain region, the silicide process This is widely used. The silicide process is a method of selectively forming silicide materials such as low-resistance cobalt silicide (CoSi ₂ ) only in the gate electrode and the source / drain regions.

1 to 3 are process flowcharts sequentially illustrating a method of manufacturing a semiconductor device in which a silicide process is used according to the prior art.

First, referring to FIG. 1, a gate electrode 14 having a spacer 16 is formed on a semiconductor substrate 10, and a drain region D and a region overlapping the gate electrode 14 are formed. Source region S is formed.

Referring to FIG. 2, when a cobalt film is formed on the entire surface of the semiconductor substrate 10 on which the resultant is formed, and then a heat treatment process is performed, a conductive drain / source region D / S and the gate electrode 14 are formed. The cobalt silicide film 18 is formed only on the upper side of the substrate). Thereafter, the cobalt film in the region excluding the region where the cobalt silicide layer 18 is formed is removed by performing an etching process.

Referring to FIG. 3, when the interlayer insulating film 20 is formed on the entire surface of the resultant, and a photolithography process is performed on the interlayer insulating film 20, the drain region formed through the interlayer insulating film 20 and formed at a lower portion thereof. When the drain region contact hole and the gate electrode contact hole are formed to expose the gate electrode G and the gate electrode G, and the conductive material is formed in the contact holes, the gate electrode contact GC and the drain region contact DC are formed. And form this process.

However, according to the conventional method described above, the spacer 16 is overgrown in the cobalt film, the gate electrode 14 and the source / drain regions S and D, which are not completely removed during wet etching, and then diffused. Conductive residues such as on cobalt silicide (CoSi2) and the cobalt silicide oxide film (CoSiOX) generated by the spacer 16 reacting with cobalt or cobalt silicide remain.

Due to conductive residues such as the cobalt film and the cobalt silicide film remaining in the spacer, there is a problem that a short circuit occurs between the gate electrode 14 and the source / drain regions S and D.

In addition, the silicide layer formed on the surface of the source / drain regions reduces the junction depth of the source / drain regions, which causes a problem of increasing the junction leakage current.

Due to the above problems, there is a problem of lowering the performance of the semiconductor device.

An object of the present invention for solving the above problems is to manufacture a semiconductor device using a silicide process to prevent the formation of conductive residues caused by the silicide process to prevent the short circuit of the gate electrode and the source / drain region In providing a method.

In addition, an object of the present invention to solve the above problems is to provide a method for manufacturing a semiconductor device using a silicide process to allow the silicide film to improve the junction leakage current caused by the reduction of the source / drain region junction depth. .

1 to 3 are process flowcharts illustrating a method of manufacturing a semiconductor device in which a silicide process according to the prior art is used;

4 to 9 are process flowcharts illustrating a method of manufacturing a semiconductor device using the silicide process according to the present invention.

* Description of the symbols for the main parts of the drawings *

30: semiconductor substrate 32: device isolation film

34: gate electrode 36: spacer

38: drain region 40: source region

42: tungsten silicide film 44: interlayer insulating film

46: cobalt film 46a: cobalt silicide film

GCH: Gate Contact Hole GC: Gate Contact

DCH: drain contact hole DC: drain contact

The idea of the present invention for achieving the above object is to form a gate electrode, a source region and a drain region on a semiconductor substrate, and to form a first high melting point metal film on the gate electrode to perform a heat treatment process to form a first high melting point metal. Forming a silicide film; Forming an interlayer insulating film on the entire surface of the resultant, and forming a contact hole through the interlayer insulating film to expose the source region or the drain region; Forming a second high melting point metal silicide layer by performing a heat treatment process by forming a second high melting point metal layer only on a bottom surface of the contact hole in the exposed source or drain region; Forming a contact hole through the resultant interlayer insulating film to expose the gate electrode; And forming a source contact or a drain contact and a gate contact by filling a conductive material in the contact hole exposing the source region or the drain region and the contact hole exposing the gate electrode. The first high melting point metal film is preferably formed of a tungsten film, and the second high melting point metal film is preferably formed of a cobalt film.

Another idea of the present invention for achieving the above object is a method of forming a silicide film in a source region or a drain region formed on a semiconductor substrate: a source contact hole or a drain contact hole inside the source or drain region to expose And forming a high melting point silicide film only on the bottom surface. In addition, it is desirable to form the high melting point silicide only at the point where the contact of the source region or the drain region is formed.

The present invention forms a high melting point silicide film only on a bottom surface of a contact hole in contact with a drain region (or a source region) to form a high melting point silicide only at a point where a contact of a source region or a drain region is formed, thereby forming a silicide film. It is to provide a method of manufacturing a semiconductor device using a silicide process that solves the problem.

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

4 to 9 are process flowcharts illustrating a method of manufacturing a semiconductor device using the silicide process according to the present invention.

First, as a first step, the gate electrode 34 and the source / drain regions 38 and 40 are formed in the semiconductor substrate 30, and the tungsten silicide film 42 is formed only on the gate electrode 34. Is shown in FIG. 4. The process of forming this state will be described in detail. When the gate oxide film and the gate conductive film are sequentially stacked on the semiconductor substrate 30 on which the device isolation film 32 is formed, and a conventional photolithography process is performed on the stacked films, the gate The electrode 34 is formed. Subsequently, an oxide film is formed on the resultant, and when a process such as etch back is performed on the film, spacers 36 are formed on both sidewalls of the gate electrode. When the gate electrode 34 including the resultant spacer 36 serves as a mask to inject ions of a conductive material into the semiconductor substrate 30, the source / drain regions 36 may be overlapped with the gate electrodes 34. , 38). Next, a process such as chemical vapor deposition is performed on the semiconductor substrate 30 on which the source / drain regions 36 and 38 and the gate electrode 34 are formed to form a tungsten (W) film, and the tungsten (W) When a process such as heat treatment is performed on the film, the tungsten silicide film 42 is formed only on the gate electrode 34. At this time, the gate electrode 34 on which the tungsten silicide layer 42 is formed is then formed with a gate electrode contact (GC of FIG. 9) to be in contact with structures such as a contact (not shown) disposed in an upper layer. Subsequently, the tungsten (W) film remaining in the region except for the region where the tungsten silicide layer is formed is removed by performing an etching process. In addition, before the tungsten (W) film is deposited, a step of removing the natural oxide film formed on the gate electrode 34 and the source / drain regions 38 and 40 may be further included.

Next, as shown in FIG. 5, when the interlayer insulating film 44 having a predetermined thickness is formed on the entire surface of the resultant, and the photolithography process is performed on the interlayer insulating film 44, the interlayer insulating film 44 ) To form a drain region contact hole (DCH) through which the drain region 38 is formed.

As shown in FIG. 6, as a third step, a cobalt film 46 is formed on the entire surface of the resultant product. In this case, the cobalt layer 46 is formed only on the bottom surface of the drain contact hole DCH, that is, the upper portion of the drain region 38.

As shown in FIG. 7, when the heat treatment process is performed on the cobalt 46 as a result, cobalt silicide is formed only on the bottom surface of the drain contact hole DCH, that is, the drain region 38 in which the contact is to be formed. A film 46a is formed. Since the cobalt silicide layer 46a is formed only in the drain contact hole DCH in which the contact is to be formed in the drain region, the problem caused by the cobalt layer deposited on the entire surface of the semiconductor substrate as in the prior art is solved. That is, the conductive residue generated by the cobalt silicide process, that is, the cobalt film is not completely removed when the cobalt film is removed except for the region in which the cobalt silicide is formed. There was a problem in that cobalt silicide transferred to a spacer and a cobalt silicide oxide film formed by reacting the spacer with cobalt or cobalt silicide remained. Since it is formed only in the (DCH), no cobalt film remaining in an unnecessary region exists, and formation of a cobalt film, a cobalt silicide film, or the like is prevented in the spacer. In addition, since the silicide layer is formed only on a part of the source / drain surface, an increase in the junction leakage current caused by the decrease in the junction depth of the source / drain region is prevented.

Subsequently, as shown in FIG. 8, when the photolithography process is performed on the interlayer insulating layer 44 on which the resultant product is formed, the gate electrode 34 formed on the lower portion of the gate electrode 34 may pass through the interlayer insulating layer 44. A gate electrode contact hole GCH is formed to expose an upper portion thereof.

As shown in FIG. 9, as a sixth step, a conductive material is formed in the gate electrode contact hole GCH and the drain region contact hole DCH formed as described above to form the gate electrode contact GC and the drain region contact DC. This process is completed by forming. In this case, the gate electrode contact GC contacts the tungsten silicide layer 42 formed on the gate electrode, and the drain region contact DC contacts the cobalt silicide layer 46a on the drain region.

Although the present embodiment is described only with respect to the drain contact in contact with the drain region, the source contact in contact with the source region can be easily changed and presented.

As described above, the formation of the cobalt silicide film on the bottom surface of the contact hole prevents the occurrence of the gate electrode and the source / drain region short circuit due to the conductive residue such as the cobalt film or the cobalt silicide film formed in the unnecessary area.

In addition, since the silicide layer is formed only on a part of the source / drain surface, an increase in the junction leakage current caused by the decrease in the junction depth of the source / drain region is prevented.

Therefore, since the above problem is solved, the performance of the semiconductor device can be improved.

As described above, by forming a cobalt silicide film on the bottom surface of the contact hole, it is possible to prevent the gate electrode and the source / drain region short circuit from being caused by conductive residues such as a cobalt film or a cobalt silicide film formed in an unnecessary area. It can be effective.

In addition, since the silicide layer is formed only on a part of the source / drain surface, there is an effect that the increase in the junction leakage current caused by the decrease in the junction depth of the source / drain region is prevented.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (7)

Forming a gate electrode, a source region and a drain region in the semiconductor substrate; Forming a first high melting point metal silicide layer by performing a heat treatment process by forming a first high melting point metal layer on the gate electrode; Forming an interlayer insulating film on the entire surface of the resultant, and forming a contact hole through the interlayer insulating film to expose the source region or the drain region; Forming a second high melting point metal silicide layer by performing a heat treatment process by forming a second high melting point metal layer only on the inner bottom surface of the exposed source region or drain region contact hole; Forming a contact hole through the resultant interlayer insulating film to expose the gate electrode; And Forming a source contact or a drain contact and a gate contact by filling a conductive material in the contact hole exposing the source region or the drain region and the contact hole exposing the gate electrode, wherein the silicide process is used. Manufacturing method. The method of claim 1, wherein the first high melting point metal film A method of manufacturing a semiconductor device, wherein a silicide process is used, which is formed of a tungsten film. The method of claim 1, wherein the second high melting point metal film A method of manufacturing a semiconductor device, wherein a silicide process is used, which is formed of a cobalt film. The method of claim 1, wherein the high melting point silicide is formed only on an inner bottom surface of the source region or the drain region contact hole. A method of manufacturing a semiconductor device in which a silicide process is used, wherein a high melting point silicide is formed only at a point where a contact of a source region or a drain region is formed. A method of forming a silicide film in a source region or a drain region formed in the semiconductor substrate, the method comprising: And forming a high melting point silicide film only on a bottom surface of the source contact hole or the drain contact hole exposing the source region or the drain region, wherein the silicide process is used. The method of claim 5, wherein the forming of the high melting point silicide layer only on the inner bottom surface of the source region or the drain region contact hole is performed. A method of manufacturing a semiconductor device in which a silicide process is used, wherein a high melting point silicide is formed only at a point where a contact of a source region or a drain region is formed. The method of claim 5, wherein the high melting silicide layer A method of manufacturing a semiconductor device, wherein a silicide process is used, which is formed of a cobalt silicide film.