JP4366805B2 - Embedding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention selectively removes titanium metal formed on the surface of a silicon substrate or the like.Regarding the embed methodThe
[0002]
[Prior art]
In general, in order to manufacture a semiconductor integrated circuit, a large number of desired elements are formed by repeatedly performing film formation and pattern etching on a silicon substrate such as a semiconductor wafer.
By the way, for the purpose of suppressing interdiffusion between Si and wiring material of the substrate, or to prevent peeling from the underlying layer, the wiring connecting each element and the lower layer of the wiring layer for making electrical contact with each element are prevented. Barrier metal is used for the purpose, but as this barrier metal, it is necessary to use a material excellent in corrosion resistance as well as having low electric resistance. In particular, TiN films tend to be frequently used as barrier metal materials that can meet such demands.
[0003]
In order to form a barrier metal of a TiN film, a very thin Ti film is generally formed by plasma CVD, this is nitrided, and a TiN film is further formed by thermal CVD. The Ti film has TiCl as a source gas._Four A film is formed by plasma CVD (Chemical Vapor Deposition) using (titanium tetrachloride) gas and hydrogen gas.
Here, a conventional method of a process for making contact with an element on the surface of a silicon substrate and a so-called salicide process will be described.
[0004]
FIG. 5 is an enlarged cross-sectional view showing a contact portion to the source region or drain region of the transistor on the surface of the silicon substrate. In the figure, W is an object to be processed made of, for example, a silicon substrate. For example, a phosphorus-doped diffusion layer 2 is partially formed on the surface of the silicon surface, and a large number of drains and sources of transistors are formed. In the illustrated example, only one representative is shown.
On the entire surface of the silicon substrate W, for example, SiO₂ An interlayer insulating film 4 is formed. A contact hole 5 is formed in a portion of the interlayer insulating film 4 corresponding to the diffusion layer 2, and the hole 5 is buried with a conductive material to form the diffusion layer 2 and The electrical connection is intended (FIG. 5A).
[0005]
Specifically, first, as shown in FIG. 5B, the entire surface of the substrate including the bottom surface in the contact hole 5 is coated with TiCl._Four Gas and H₂ A very thin Ti (titanium) metal film 6 is formed by plasma CVD in the presence of gas. The process temperature at this time is, for example, about 580 to 620 ° C., and the process pressure is, for example, about 665 Pa (≈5 Torr).
In this case, the Ti metal film deposited on the bottom surface of the contact hole 5 immediately reacts with the silicon of the underlying diffusion layer 2 to become a TiSix (titanium silicide) film 8, and the target TiSix film 8 can be formed.
[0006]
Next, as shown in FIG. 5C, the Ti metal film 6 is nitrided by plasma in the presence of ammonia gas and hydrogen gas to change to a TiN film 9. The purpose of this treatment is to make the film difficult to peel by nitriding the Ti metal film 6. The process temperature at this time is, for example, about 580 to 620 ° C., and the process pressure is about 665 Pa (≈5 Torr). Next, as shown in FIG._Four A second TiN film 10 is formed as a barrier metal on the entire surface including the side wall in the contact hole 5 by thermal CVD in the presence of gas and ammonia gas. At this time, the process temperature is, for example, about 580 ° C., and the process pressure is, for example, about 40 Pa (≈300 mTorr). TiCl_Four Is about 30 sccm, NH_Three The gas flow rate is about 400 sccm.
[0007]
Then, as shown in FIG. 5E, the wiring layer 12 is formed on the entire surface by filling the contact hole 5 with a conductive material made of, for example, tungsten. The wiring layer 12 is then subjected to pattern etching.
Moreover, FIG. 6 is explanatory drawing explaining a general salicide process. This salicide process is a method of simultaneously forming a part of the barrier metal in the gate electrode, the source region, and the drain region. As shown in FIG. 6A, a source region 20 and a drain region 22 of, for example, phosphorous doped polysilicon are formed on the surface of the silicon substrate W, and between the source region 20 and the drain region 22 are formed. , SiO₂ A gate electrode 26 made of, for example, a phosphorus-doped polysilicon film is provided surrounded by an interlayer insulating film 28 via a gate oxide film 24 made of the same.
[0008]
First, as shown in FIG. 6B, TiCl is formed on the entire surface of the substrate._Four Gas and H₂ A very thin Ti metal film 30 is formed by plasma CVD in the presence of gas. As described in FIG. 5B, the process conditions at this time are a process temperature of about 580 to 620 ° C. and a process pressure of about 665 Pa (≈5 Torr), for example.
In this case, the titanium metal film deposited on the gate electrode 26, the source region 20 and the drain region 22 immediately reacts with silicon in the underlying polysilicon layer to become a TiSix film 32.
Next, as shown in FIG. 6C, the Ti film 30 is nitrided with plasma in the presence of ammonia gas and hydrogen gas, and changed to a TiN film 34. As in the case of FIG. 5C, the process conditions at this time are a process temperature of, for example, about 580 to 620 ° C. and a process pressure of, for example, about 665 Pa (≈5 Torr).
[0009]
Next, as shown in FIG. 6D, wet etching is performed using ammonia hydrogen peroxide water, and only the TiN film 34 is selectively removed leaving the TiSix film 32 formed by the reaction. .
Next, as shown in FIG. 6E, the entire surface of the silicon substrate is made of, for example, SiO.₂ An insulating layer 37 is formed so as to fill the entire surface. Next, as shown in FIG. 6F, the insulating layer 37 is selectively etched to contact each TiSix film 32 provided corresponding to the source region 20, the drain region 22, and the gate electrode region. Hole 38 is formed.
Then, as shown in FIG. 6 (G), TiCl_Four A second TiN film 35 as a barrier metal is formed on the entire surface of the substrate by thermal CVD in the presence of gas and ammonia gas. In this case, the second TiN film 35 is deposited also on the inner side surface and the bottom surface of each contact hole 38. The process conditions at this time are the same as in FIG. 5D, for example, the process temperature is about 580 ° C. and the process pressure is about 40 Pa (≈300 mTorr).
Then, as shown in FIG. 6G, a wiring layer 36 is formed on the entire surface with a conductive material made of, for example, tungsten. At the same time, the contact holes 38 are also buried. The wiring layer 36 and the TiN film 35 are then subjected to pattern etching.
[0010]
[Problems to be solved by the invention]
By the way, in the process shown in FIG. 5, the Ti film 6 is changed to the TiN film 9 by nitriding as shown in FIGS. 5 (B) and 5 (C) so that peeling or the like hardly occurs. Although the adhesion of this part is improved, in order to deposit the TiSix film 8 having a desired thickness on the bottom surface of the contact hole 5, the film formation time becomes longer and the Ti film 6 tends to be considerably thicker. . Under such circumstances, it is necessary to completely nitride the Ti film 6 from the viewpoint of preventing film peeling. However, if the Ti film 6 becomes too thick as described above, for example, to completely nitride, Ti Since it takes time in proportion to approximately the square of the thickness of the film, it takes a long time to complete nitridation, resulting in a problem that throughput is lowered.
[0011]
  In addition, as high miniaturization and high integration are promoted, and the design rules for integrated circuit design become stricter as in the present day, for example, the opening width of the contact hole 5 becomes smaller. Under such circumstances, when the Ti film 6 is formed as shown in FIG. 5B, an overhang portion 6A of the Ti film 6 is generated in a shape protruding to the opening of the contact hole 5. This acts to sandwich the opening area. As a result, there is a problem in that a void 14 is generated in the buried portion of the contact hole 5 when the wiring layer 12 is formed in a later process, as shown in FIG.
  Further, in the case of the salicide process shown in FIG. 6, there is a problem that the total number of processes is required.
  The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to improve throughput by selectively removing titanium metal by dry etching.Provide an embedding method that canThere is to be.
[0012]
[Means for Solving the Problems]
  The related art of the present invention isIn an etching method that selectively removes titanium metal formed on the surface of the treatment body by etching, titanium chloride gas is used as an etching gas. Thereby, it becomes possible to dry-etch titanium metal efficiently and selectively.
  thisIf the aboveTitanium chloride is TiCl₄ Can be used.
[0013]
  ContractRequirement 1The invention to be defined includes a titanium film forming step of forming a titanium metal film on the surface of the object to be processed in a method of embedding a hole including a groove formed on the surface of the object to be processed made of a silicon substrate, and the titanium Excluding the portion where the surface of the metal film is combined with the substrate using titanium chloride gas as the etching gasSo that the titanium metal film remains.Etching process that removes a uniform thickness approximately uniformlyAnd a nitriding step of nitriding the remaining titanium metal film after the etching step;It is made to have.
  As described above, the titanium metal film is removed by dry etching substantially uniformly by a predetermined thickness except for the portion combined with the base.Then, the remaining titanium metal film is nitridedThus, for example, the remaining titanium metal film can be thinned to a desired thickness. Accordingly, the time for completely nitriding the remaining titanium metal film can be greatly shortened, and thus the throughput of the entire embedding process can be improved.It is possible to
  In this case, for example, as defined in claim 2, a titanium nitride film forming step for forming a titanium nitride film on the surface of the object to be processed, and the inside of the hole is embedded in the surface of the object to be processed. A wiring layer forming step of forming a wiring layer.
For example, as defined in claim 3, the titanium nitride film forming step is performed by thermal CVD.
For example, as defined in claim 4, the titanium film forming step is performed by plasma CVD.
For example, as defined in claim 5, the titanium film forming step and the etching step are performed by the same processing apparatus.
[0014]
  The related technology of the present invention is:In a method of filling a hole including a groove formed on a surface of an object to be processed made of a silicon substrate, a titanium film forming step of forming a titanium metal film on the surface of the object to be processed; and a surface of the titanium metal film And an etching step for removing everything except the portion combined with the base using titanium chloride gas as an etching gas.
  According to this, since the titanium metal film is completely removed by dry etching except for the portion combined with the base, there is no need to perform nitriding treatment of the titanium film in the subsequent process, and the throughput is improved accordingly. In particular, even if the diameter of the hole including the wiring groove is small, it is possible to prevent the diameter from becoming smaller due to the overhang portion of the titanium metal film.
  thisIf theA titanium nitride film forming step of forming a titanium nitride film on the surface of the object to be processed, and a wiring layer forming step of forming a wiring layer in the surface of the object to be embedded in the hole You may make it have.
[0015]
  Related techniques of the present invention are described in TableIn a wiring layer forming method for forming a wiring layer on a target object having a gate electrode, a source region, and a drain region formed on a surface, a titanium film forming step of forming a titanium metal film on a surface of the target object; And an etching process for removing the entire surface of the titanium metal film except for a portion combined with the base using a titanium chloride gas as an etching gas.
  As described above, since the titanium metal film is completely removed except for the portion combined with the base, the subsequent nitriding treatment can be made unnecessary, and the throughput can be improved correspondingly.
  thisIfAfter the etching step, an insulating layer forming step for forming an insulating layer on the surface of the object to be processed, a contact hole forming step for forming a contact hole at a predetermined position of the insulating layer, and titanium on the surface of the object to be processed You may make it have the titanium nitride film formation process which forms a nitride film, and the wiring layer formation process which forms a wiring layer in the surface of the said to-be-processed object.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  In the following, the present inventionReality of the embedding methodExamples will be described in detail with reference to the accompanying drawings.
  The etching method of the present invention is characterized in that a titanium chloride gas is used as an etching gas in an etching method for selectively removing titanium metal formed on the surface of an object to be processed such as a silicon substrate by etching. In this case, as the titanium chloride, for example, TiCl₄ Can be used.
  Further, the present invention is characterized in that the titanium metal (film) film formation and the etching are continuously performed in, for example, the same processing apparatus. If necessary, a TiN film (titanium nitride film) can also be formed by thermal CVD in this processing apparatus.
[0017]
First, a processing apparatus that continuously forms a titanium metal film and performs this etching will be described.
FIG. 1 is a block diagram showing a processing apparatus for carrying out all or part of the method of the present invention. As shown in the figure, the processing apparatus 40 has a processing container 42 formed into a cylindrical shape by, for example, stainless steel, and the processing container 42 is grounded. An exhaust port 46 for exhausting the atmosphere in the container is provided at the bottom 44 of the processing container 42, and an exhaust system 50 provided with a vacuum pump 48 is connected to the exhaust port 46. The inside of the processing vessel 42 can be uniformly evacuated from the bottom peripheral portion.
[0018]
In this processing container 42, a disk-shaped mounting table 54 is provided via a support column 52 made of a conductive material, and a silicon substrate W, for example, can be mounted thereon as an object to be processed. ing. Specifically, the mounting table 54 also serves as a lower electrode, and includes a lower table 54A that is directly supported by the support column 52 and an upper table 54B that is bonded to the upper surface. A heater 56 is sandwiched. The lower base 54A and the upper base 54B are joined by welding, for example, at the joint surface.
[0019]
A ceiling plate 60 integrally provided with a shower head 58 that also serves as an upper electrode is airtightly attached to the ceiling of the processing vessel 42 via an insulating material 62 with respect to the side wall of the vessel. The shower head 58 is provided so as to face almost the entire upper surface of the mounting table 54, and a processing space S is formed between the shower head 58 and the mounting table 54. The shower head 58 introduces various gases into the processing space S in a shower shape, and a plurality of injection holes 66 for injecting gas are formed on the injection surface 64 on the lower surface of the shower head 58.
[0020]
A gas introduction port 68 for introducing gas into the head is provided above the shower head 58, and a supply passage 70 for flowing gas is connected to the gas introduction port 68.
A plurality of branch pipes 72 are connected to the supply passage 70, and each branch pipe 72 has, for example, TiCl as a gas that serves as both a film forming gas and an etching gas._Four TiCl to store gas_Four Gas source 74, H₂ H to store gas₂ Gas source 76, Ar gas source 78 storing, for example, Ar gas as plasma gas, NH storing ammonia_Three Gas source 80 and N₂ Gas sources 82 are connected to each other. The flow rate of each gas is controlled by a flow rate controller provided in each branch pipe, for example, a mass flow controller 84. Each branch pipe 72 is provided with an on-off valve 86 for supplying and stopping the supply of each gas as necessary. Here, the case where each gas is supplied in a mixed state in one supply passage 70 is shown, but the present invention is not limited to this, and a part or all of the gases are individually supplied into different passages. In addition, a so-called postmix gas conveyance mode in which the gas is mixed in the shower head 58 or in the processing space S may be used.
[0021]
In addition, a matching circuit 90 and a high frequency power source 92 for plasma of, for example, 450 KHz are connected to the ceiling plate 60 through lead wires 88 in order to form plasma when forming a Ti film. The lead wire 88 is provided with an open / close switch 94 that cuts off the supply of high-frequency power as necessary.
A gate valve 96 that can be opened and closed in an airtight manner when the substrate W is loaded and unloaded is provided on the side wall of the processing container 42.
[0022]
Next, a film forming method and an etching method performed using the apparatus configured as described above will be schematically described.
First, at the time of forming the Ti film, the silicon substrate W is introduced into the processing container 42 through the opened gate valve 96 and placed on the mounting table 54 to seal the processing container 42 inside. On the surface of the silicon substrate W, for example, a contact hole for making contact with a transistor on the substrate has already been formed in the previous step.
If the inside of the processing container 42 is sealed, TiCl is used as a film forming gas._Four Gas and H₂ Ar gas as a plasma gas is introduced into the processing vessel 42 from the shower head 58 at a predetermined flow rate, and the processing vessel 42 is evacuated by the vacuum pump 48 to maintain a predetermined pressure.
[0023]
At the same time, a high frequency of 450 KHz is applied from the high frequency power source 92 to the shower head 58 as the upper electrode, and a high frequency electric field is applied between the shower head 58 and the mounting table 54 as the lower electrode. As a result, Ar gas is turned into plasma, and TiCl_Four Gas and H₂ A reduction reaction with the gas is promoted, and a Ti film is formed on the substrate surface. The temperature of the substrate W is maintained at a predetermined temperature by a resistance heater 56 embedded in the mounting table 54.
[0024]
For example, when processing an 8-inch substrate, the substrate temperature (mounting table temperature) is about 580 to 620 ° C., and the process pressure is about 665 Pa (≈5 Torr). TiCl_Four Gas is about 5 sccm, H₂ The gas is about 1500 sccm, and the Ar gas is about 300 sccm. The film formation time is about 60 seconds, and the thickness of the Ti film is about 200 mm. Regarding the Ti film formation, if plasma is not used, the process temperature must be as high as about 900 ° C. However, by using plasma in this way, the process temperature can be lowered to about 600 ° C.
[0025]
In this way, when a titanium metal film having a predetermined thickness is formed, the titanium metal or the titanium metal film is continuously formed in the processing apparatus except for the portion combined with the silicon atom of the underlying silicon layer. Etching is performed.
In this etching process, plasma is not used by opening the open / close switch 94 and cutting off the supply of high-frequency power, and the etching gas is TiCl._Four Only gas is supplied into the processing vessel 42. The process conditions at this time include, for example, a process temperature in the range of 580 to 620 ° C., a process pressure of about 665 Pa (≈5 Torr), TiCl_Four The maximum gas flow rate is about 30 sccm. As a result, the titanium metal or the titanium metal film excluding the TiSix film reacted with the base can be removed by etching.
[0026]
Next, the embedding method of the present invention including the above-described titanium film forming step and titanium metal film etching step will be described.
FIG. 2 is a process diagram showing an example of the embedding method of the present invention. The same components as those shown in FIG. 5 will be described with the same reference numerals.
In the figure, W is an object to be processed made of, for example, a silicon substrate. For example, a phosphorus-doped diffusion layer 2 is partially formed on the surface of the silicon surface, and a large number of drains and sources of transistors are formed. In the illustrated example, only one representative is shown.
On the entire surface of the silicon substrate W, for example, SiO₂ An interlayer insulating film 4 is formed. A contact hole 5 is formed in a portion of the interlayer insulating film 4 corresponding to the diffusion layer 2, and the hole 5 is buried with a conductive material to form the diffusion layer 2 and The electrical connection is intended (FIG. 2 (A)). Note that the method of the present invention can also be applied to the case of embedding a through hole, a wiring groove, or the like instead of the contact hole.
[0027]
Specifically, first, as shown in FIG. 2B, TiCl is formed on the entire surface of the substrate including the bottom surface in the contact hole 5._Four Gas and H₂ A very thin Ti (titanium) metal film 6 is formed by plasma CVD in the presence of gas. At this time, Ar gas is added as a plasma gas. This titanium film forming step is performed in the processing apparatus 40 shown in FIG. 1 as described above. As described above, the process temperature at this time is, for example, about 580 to 620 ° C., and the process pressure is, for example, about 665 Pa (≈5 Torr).
In this case, the Ti metal film 6 deposited on the bottom surface of the contact hole 5 immediately reacts with the silicon of the underlying diffusion layer 2 to become a TiSix (titanium silicide) film 8. Next, in this processing apparatus 40, TiCl is used as an etching gas._Four As shown in FIG. 2C, an etching process is performed in which the surface of the titanium metal film 6 except the TiSix film 8 is removed by etching to a predetermined thickness by flowing only gas. In this etching process, plasma is not generated without applying a high frequency power source.
[0028]
As described above, the process conditions at this time are as described above. For example, the process temperature is in the range of 580 to 620 ° C., the process pressure is about 665 Pa (≈5 Torr), TiCl_Four The maximum gas flow rate is about 30 sccm. As a result, the titanium metal or titanium metal film 6 excluding the TiSix film 8 that has reacted with the base can be removed by etching to a predetermined thickness.
Thereby, the titanium metal film 6 having the thickness t1 can be reduced to the thickness t2. The thickness t2 is, for example, about 100 mm, and is set to such a thickness that the subsequent nitriding step can be performed in a short time. As described above, when the etching process is completed, the process proceeds to the nitriding process.
[0029]
In this nitriding step, as shown in FIG. 2D, the Ti metal film 6 is nitrided by plasma in the presence of ammonia gas and hydrogen gas, and changed to a TiN film 9. The process temperature at this time is, for example, about 580 to 620 ° C., and the process pressure is about 665 Pa (≈5 Torr). In this case, since the thickness t2 of the Ti metal film 6 is very thin as described above, the Ti metal film 6 can be completely nitrided in a very short time. This nitriding process can also be performed in the processing apparatus 40 shown in FIG. Next, as shown in FIG._Four A second TiN film 10 is formed as a barrier metal on the entire surface including the side wall in the contact hole 5 by thermal CVD in the presence of gas and ammonia gas. The titanium nitride film forming step can also be performed in the processing apparatus 40 shown in FIG. 1. The process temperature at this time is, for example, about 580 ° C., and the process pressure is, for example, about 40 Pa (≈300 mTorr).
[0030]
Then, as shown in FIG. 2F, a wiring layer forming step is performed in which the contact hole 5 is filled with a conductive material made of tungsten, for example, and the wiring layer 12 is formed on the entire surface. The wiring layer 12 is then subjected to pattern etching.
In the method of the present invention shown in FIG. 2, the number of steps is increased by adding an etching step as compared with the step shown in FIG. 5, but the thickness of the titanium metal film 6 is thick as described above. The amount of time required for the nitriding step is significantly shortened as the thickness is reduced to t2, and the entire processing time is shortened accordingly, thereby improving the throughput.
[0031]
In the above embodiment, the titanium metal film 6 is left by the thickness t2 in the etching process shown in FIG. 2C. Instead, as shown in FIG. TiCl without leaving any_Four All may be removed by etching with gas. According to this, since the overhang portion 6A (see FIG. 2B) of the titanium metal film 6 protruding from the opening of the contact hole 5 is also eliminated, the design rule is particularly strict and the hole diameter is very small. In this case, since the substantial hole diameter does not need to be narrowed, hole filling in the subsequent process is sufficiently performed, and generation of voids (see FIG. 5E) can be prevented here. .
Further, in this case, the nitriding step shown in FIG. 2D can be omitted, and the process can suddenly shift to the titanium nitride film forming step shown in FIG. It can be reduced by a small amount, and the throughput can be further improved.
[0032]
Next, the wiring layer forming method of the present invention including the above-described titanium film forming step and titanium metal film etching step will be described.
FIG. 4 is a process diagram showing an example of the wiring layer forming method of the present invention, and the same parts as those shown in FIG.
This wiring layer forming process includes the above-described salicide process, and this salicide process is a method of forming part of the barrier metal in the gate electrode, the source region, and the drain region at the same time. As shown in FIG. 4A, a source region 20 and a drain region 22 of, for example, phosphorus-doped polysilicon are formed on the surface of the silicon substrate W, and between the source region 20 and the drain region 22 are formed. , SiO₂ A gate electrode 26 made of, for example, a phosphorus-doped polysilicon film is made to pass through a gate oxide film 24 made of,₂ It is provided surrounded by an interlayer insulating film 28 made up of.
[0033]
First, as shown in FIG. 4 (B), TiCl is formed on the entire surface of the substrate._Four Gas and H₂ A very thin Ti metal film 30 is formed by plasma CVD in the presence of gas. At this time, Ar gas is added as a plasma gas. Further, this titanium film forming step is performed in the processing apparatus 40 shown in FIG. 1 as described above. The process conditions at this time are, for example, a process temperature of about 580 to 620 ° C. and a process pressure of about 665 Pa (≈5 Torr), as described with reference to FIG.
In this case, the titanium metal film deposited on the gate electrode 26, the source region 20 and the drain region 22 immediately reacts with silicon in the underlying polysilicon layer to become a TiSix film 32. When the titanium film forming step is completed in this way, next, TiCl is used as an etching gas in the processing apparatus 40._Four By flowing only gas, an etching process is performed in which all of the titanium metal film 30 except the TiSix film 32 is removed by etching as shown in FIG. In this etching process, plasma is not generated without applying a high frequency power source.
[0034]
As described in FIG. 2C or FIG. 3, the process conditions at this time include, for example, a process temperature in the range of 580 to 620 ° C., a process pressure of about 665 Pa (≈5 Torr), TiCl_Four The maximum gas flow rate is about 30 sccm. As a result, the titanium metal or the titanium metal film excluding the TiSix film reacted with the base can be removed by etching.
When the etching process is thus completed, the process proceeds to the insulating layer forming process. This step is the same as the step shown in FIG. 6E. As shown in FIG. 4D, the entire surface of the silicon substrate is made of, for example, SiO.₂ An insulating layer 37 is formed so as to fill the entire surface.
Next, when this insulating layer forming step is completed, the process proceeds to a contact hole forming step. This step is the same as the step shown in FIG. 6F, and as shown in FIG. 4E, each of the steps provided corresponding to the source region 20, the drain region 22, and the gate electrode region. The insulating layer 37 is selectively etched toward the TiSix film 32 to form a contact hole 38.
Next, when this contact hole forming step is completed, the process proceeds to a titanium nitride film forming step. This step is the same as the step shown in FIG. 6G, and as shown in FIG._Four A second TiN film 35 as a barrier metal is formed on the entire surface of the substrate by thermal CVD in the presence of gas and ammonia gas. The process conditions at this time are, for example, a process temperature of about 580 ° C. and a process pressure of about 40 Pa (≈300 mTorr), as in FIG. Then, as shown in FIG. 4G, a wiring layer 36 is formed on the entire surface with a conductive material made of, for example, tungsten. The process shown in FIG. 4G is the same as the process shown in FIG. 6H, and the wiring layer 36 and the TiN film 35 are thereafter subjected to pattern etching.
[0035]
Thus, in the wiring layer forming method of the present invention, TiCl_Four Since the titanium metal film is completely removed by the etching process using the etching gas as the etching gas, the two processes shown in FIGS. 6C and 6D can be combined into one process. Therefore, the throughput can be greatly improved.
It should be noted that the temperature, pressure, gas flow rate, etc. used in the above embodiments are merely examples, and of course are not limited thereto. In addition, although a silicon substrate is used as an object to be processed here, the present invention is not limited to this, and it is needless to say that the method of the present invention can be applied to an LCD substrate and a glass substrate.
[0036]
【The invention's effect】
  As explained above, the present inventionDepending on how to embedAs a result, the following excellent effects can be achieved.
  According to the related art of the present invention,Tan metal can be efficiently and selectively dry-etched.
  According to the present invention, Titanium metal film is removed by dry etching almost uniformly by a predetermined thickness, excluding the part combined with the base.And then nitride the remaining titanium metal filmThus, the remaining titanium metal film can be thinned to a desired thickness. Accordingly, the time for completely nitriding the remaining titanium metal film can be greatly shortened, and therefore the throughput of the entire embedding process can be improved.
  According to the related art of the present invention,Since the titanium metal film is completely removed by dry etching except for the portion combined with the base, there is no need to perform nitriding treatment of the titanium film in the subsequent process, and the throughput can be improved accordingly. In particular, even if the diameter of the hole including the groove for wiring is small, it is possible to prevent the diameter from becoming smaller due to the overhang portion of the titanium metal film.
  According to the related art of the present invention,Since the titanium metal film is completely removed except for the portion combined with the base, the nitriding process and the wet etching process can be combined into one process, and the throughput can be improved accordingly. .
[Brief description of the drawings]
FIG. 1 is a block diagram showing a processing apparatus for carrying out all or part of the method of the present invention.
FIG. 2 is a process diagram showing an example of an embedding method according to the present invention.
FIG. 3 is an explanatory diagram for explaining a modification of the embedding method of the present invention.
FIG. 4 is a process diagram showing an example of a wiring layer forming method of the present invention.
FIG. 5 is an enlarged cross-sectional view showing a contact portion to a source region or a drain region of a transistor on the surface of a silicon substrate.
FIG. 6 is an explanatory diagram for explaining a general salicide process.
[Explanation of symbols]
20 Source area
22 Drain region
24 Gate oxide film
26 Gate electrode
28 Interlayer insulation film
30 Titanium (Ti) metal film
32 TiSix film
35 Titanium nitride (TiN) film
36 Wiring layer
37 Insulation layer
38 Contact hole
40 processor
42 Processing container
54 mounting table
56 Resistance heater
58 shower head
92 High frequency power supply
94 Open / close switch
W Silicon substrate (object to be processed)

Claims (5)

In a method of filling a hole including a groove formed on a surface of an object to be processed made of a silicon substrate, a titanium film forming step of forming a titanium metal film on the surface of the object to be processed; and a surface of the titanium metal film An etching step of removing the titanium metal film substantially uniformly by a predetermined thickness so that the titanium metal film remains except for a portion combined with a base by using titanium chloride gas as an etching gas; and the titanium remaining after the etching step And a nitriding step of nitriding the metal film . Wherein the titanium nitride film formation step of forming a titanium nitride film on the surface of the object to be processed, said the surface of the object, that has a wiring layer forming step of forming a wiring layer so as to fill the holes embedding method of請Motomeko 1, wherein. 3. The embedding method according to claim 2, wherein the titanium nitride film forming step is performed by thermal CVD. The embedding method according to claim 1, wherein the titanium film forming step is performed by plasma CVD. The embedding method according to claim 1, wherein the titanium film forming step and the etching step are performed by the same processing apparatus.

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