JP2592281B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for manufacturing a semiconductor device in which tungsten or molybdenum is filled in a contact hole. In a method of manufacturing a semiconductor device in which a contact hole is filled with tungsten, a step of forming tungsten to a thickness capable of filling the inside of the contact hole by sputtering is provided, A method of manufacturing a semiconductor device, comprising a step of removing, by solution etching, a tangte formed in a portion other than a hole and partially peeling from a base, and a method of manufacturing a semiconductor device in which a contact hole is filled with molybdenum. Spatter Manufacturing a semiconductor device, comprising: a step of forming the entire surface of the contact hole with a ring to a thickness that can be embedded therein; and a step of removing molybdenum formed in a portion other than the contact hole and partially peeled off from a base by solution etching. Including and configuring the method.

[Industrial applications]

The present invention relates to a method for manufacturing a semiconductor device in which tungsten or molybdenum is filled in a contact hole.

[Conventional technology]

FIG. 2 is a perspective view of the surface in which tungsten is formed by the CVD method, in which (a) is a deposited state diagram, and (b) is 1100 ° C.
FIG. 3 is a perspective view of the surface on which tungsten is formed by a sputtering method. FIG. 3A is a state diagram after deposition, and FIG. 3B is a state diagram after annealing at 1100 ° C. 2 and 3 are drawings based on photographs.

Conventionally, for example, when a contact hole is filled with tungsten, it has been attempted to use a selective chemical vapor deposition (selective CVD) method or a sputtering method (PVD). However, when actually filling holes by selective CVD using tungsten, filling is possible, but the measured average of crystal grains is 50
This is about 0 °, which is larger than about 260 ° in the case of the sputtering method, and is not suitable as an embedding method if the crystal grains are large when the contact hole is miniaturized with the integration of the IC. It is desirable that the crystal grains of the embedding material be as small as possible.

Referring to the drawings based on the photographs shown in FIGS. 2 and 3, in the case of the sputtering method shown in FIG.
Although it is relatively flat at about 00 mm and does not hinder the formation of the upper layer wiring, in the case of the selective CVD method shown in FIG. There is a possibility that trouble may occur when forming the element.

Furthermore, in the case of the selective CVD method, there is a problem that the substrate surface at the bottom of the contact hole is eroded by tungsten so that it is likely to bite.

Therefore, if it is attempted to fill the contact hole using a sputtering method in which the crystal grains are small and the surface is flat, it is difficult to fill the contact hole, and a thick film must be formed to completely fill the contact hole. However, when the tungsten is formed thickly, the adhesion to the base is poor, so that when the wafer is warped after the sputtering, a compressive stress acts on the tungsten layer and the tungsten is peeled off from the base, resulting in an uneven wave as shown in FIG. Hit the state,
It was impossible to form wiring lines on this.

[Problems to be Solved by the Invention] As described above, the conventional method for manufacturing a semiconductor device is not preferable because the crystal grains and surface irregularities are large even if the contact holes are to be filled using the selective CVD method or the sputtering method, There were various problems such as peeling of the layer and the like, which was not practical.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a semiconductor device in which a contact hole can be filled with a filling material having as small a crystal grain as possible so that the surface becomes flat.

[Means for solving the problem]

The above object is achieved by a method of manufacturing a semiconductor device in which a contact hole is filled with tungsten, a step of forming tungsten on the entire surface to a thickness capable of filling the inside of the contact hole by sputtering, and removing tungsten formed from other than the contact hole and peeled off from the base. A method for manufacturing a semiconductor device, comprising the step of removing by solution etching, and a method for manufacturing a semiconductor device, wherein a contact hole is filled with molybdenum. The problem is solved by a method for manufacturing a semiconductor device, comprising a step of forming and a step of removing molybdenum formed in a portion other than the contact hole and peeled off from a base by solution etching.

[Action]

In the present invention, a method is used in which tungsten or molybdenum is grown over the entire surface by sputtering so as to be able to fill the inside of the contact hole, and tungsten or molybdenum formed outside the contact hole and partially removed from the base by solution etching is used. By doing so, it is possible to obtain small crystal grains and flatness of the surface, which are advantages of embedding by sputtering, and to remove the peeled part from the base of the thick tungsten or molybdenum layer which had a problem in the case of sputtering by solution etching. It turns out that it can be removed neatly. This is because the etching rate is increased in a portion where the etching solution enters and is separated from a space formed by peeling from the base, and conversely, tungsten or molybdenum in a contact hole portion where the etching solution is most difficult to enter remains. As a result, as shown in FIG. 1 (b), tungsten or molybdenum was filled in the contact hole, and a filled state having a flat surface was obtained.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the illustrated embodiments.

1 (a) to 1 (c) are process sectional views of this embodiment, in which 11 is a contact hole, 12 is tungsten,
13 is a phosphorus silicate glass layer, 14 is a silicon substrate, 15 is a space, 16 is an Al wiring, and 22 is molybdenum.

As shown in FIG. 1A, the method of manufacturing a semiconductor device according to the present embodiment is such that a phosphorus-silicate glass layer 13 is formed on a silicon substrate 14.
Was formed with a thickness of 1 [mu] m, through an etching mask (not shown) the contact hole 11 of the vertical and horizontal 1 [mu] m CF ₃ 57
Reactive ion etching (RIE) is performed in an atmosphere of _SCCM and CF ₄ 48 _SCCM under the conditions of an output of 1 KW and a pressure of 0.3 Torr.

Next, 0.8 μm of tungsten (W) as an embedding material
A thickness of m is deposited on the surface using a sputtering method.
If tungsten is deposited with this thickness, the inside of the contact hole can be completely filled. The sputtering apparatus used was a single-wafer target / wafer facing type, and the sputtering was performed without heat treatment for 120 seconds using an output of 4 KW, a pressure of 5 mTorr, and argon (Ar) 40 _SCCM . When the tungsten layer thus formed is subjected to a compressive stress due to the return of the warp of the wafer or the like, the space 15 is separated from the underlying phosphorus-silicate glass layer 13 as shown in FIG. 1A.

The peeled tongue 12 layer is removed by solution etching. The etching solution is a mixture of H ₂ O ₂ : HNO ₃ : H ₂ O = 1: 5: 5, and is boiled at 70 ° C. At this time, the etching rate except for the contact hole is 4970Å.
/ Min, etching rate in contact hole is 1030Å
/ Min. Since the partially peeled portion is removed about five times faster than the contact hole, the tungsten in the contact hole remains as shown in FIG. It is possible to flatten the surface by removing only the tungsten on 13.

Finally, as shown in FIG. 1 (c), even if an Al wiring 16 is formed thereon, the surface of the base is flat and the contact holes are filled with tungsten having small crystal grains and small irregularities. Contact can be reliably established.

In this embodiment, tungsten is used as the filling material. However, molybdenum other than tungsten can be suitably filled in the contact hole by going through the same steps as described above.

〔The invention's effect〕

As described above, according to the present invention, since tungsten or molybdenum is buried in the contact hole by sputtering, it is possible to fill the surface with small crystal grains evenly, and to remove excess from the base other than the contact hole. Tungsten or molybdenum can flatten the surface by solution etching, thus making it possible to form a suitable upper wiring.

[Brief description of the drawings]

1 (a) to 1 (c) are process sectional views of an embodiment of the present invention, FIG. 2 is a surface perspective view in which tungsten is formed by a CVD method, (a) is a deposited state diagram, and (b) is Phase diagram after annealing at 1100 ° C. FIG. 3 is a surface perspective view in which tungsten is formed by a sputtering method, (a) is a deposited phase diagram, (b) is 11
FIG. 4 is a state diagram after annealing at 00 ° C. In the figure, 11 indicates a contact hole, 12 indicates tungsten, 13 indicates a phosphorus-silicate glass layer, 14 indicates a silicon substrate, 15 indicates a space, 16 indicates an Al wiring, and 22 indicates molybdenum.

Claims (2)

(57) [Claims] A method of manufacturing a semiconductor device in which a contact hole (11) is filled with tungsten (12), wherein tungsten (12) is formed by sputtering over the entire surface so as to fill the contact hole (11). A method for manufacturing a semiconductor device, comprising: removing a tungsten (12) formed in a portion other than a contact hole (11) and partially peeled off from a base by solution etching. 2. The method according to claim 1, wherein the contact hole is formed of molybdenum (2).
2) A method of manufacturing a semiconductor device in which the holes are filled with: a step of forming molybdenum (22) on the entire surface by sputtering so as to fill the contact holes (11); A method for manufacturing a semiconductor device, comprising a step of removing molybdenum (22) that has been partially removed by solution etching.