JPH02308524A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To solve the problem caused by the growth speed of material being uniform under the same conditions and to quicken the growth speed so as to improve productivity by forming a ground electrode capable of selective growth of electrode material at the side wall of a second contact hole in a semiconductor region, and selectively growing electrode material at the same time inside this second contact hole. CONSTITUTION:A first semiconductor region 11, inside an insulating film 2 formed on a semiconductor substrate, and a second semiconductor region 12 are formed and a first contact hole 21 is formed for this region 11, and a second contact hole 22 shallower than this hole 21 is formed for the region 12. Moreover, a ground conductive layer 4 capable of selective growth of electrode material is formed at least at the side wall of the second hole 22. Ground electrodes layers capable of selectively growing electrode materials 31 and 32 are formed at the same time inside these first and second holes 21 and 22 so as to quicken the growth speeds of contact holes whose depths are different, whereby the productivity of a semiconductor device is improved.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

Industrial field of application Outline of the invention Conventional technology Problems to be solved by the invention Examples of means and effects for solving the problems Example-1 (Figures 1 and 1') Example-2 ( Figure 2) Example 3 (Figure 3) Example 4 (Figure 4A) Example 5 (Figure 4B) Effects of the Invention [Field of Industrial Application] The present invention provides a method for manufacturing a semiconductor device. Regarding. In particular, the present invention relates to a method for manufacturing a semiconductor device including a step of selectively growing an electrode material in a contact hole, and can be used in manufacturing processes for various semiconductor devices having contact holes.

[Summary of the invention]

The invention according to claim 1 of the present invention provides a method for manufacturing a semiconductor device in which a first contact hole and a second contact hole deeper than the first contact hole are formed.

By forming a base conductive layer on which an electrode material can be selectively grown on at least the side wall of the contact hole, and selectively growing the electrode material in the first and second contact holes at the same time, a deep second contact hole can be formed. The selective growth of the electrode material is accelerated and the electrode material is uniformly grown in both the first and second contact holes.

The invention of claim 2 of the present invention provides a base conductive film that selectively forms a metal nitride film on the bottom surface of a contact hole formed in an insulating film, and allows selective growth of an electrode material in the contact hole and on the insulating film. The electrode material is selectively grown in the contact hole by forming a layer and anisotropically etching the base conductive layer in a selectivity with respect to the metal nitride film to leave the base conductive layer on the side wall of the contact hole. It is designed to increase speed and improve productivity.

The invention according to claim 3 of the present invention is a method for manufacturing a semiconductor device having a first contact hole and a second contact hole deeper than the first contact hole. , 1st. a step of selectively growing an electrode material having a thickness substantially equal to the difference in depth of the second contact hole; a step of forming a first contact hole; By comprising the step of simultaneously selectively growing an electrode material in the second contact hole, the first. Both contact holes of mz are uniformly filled with electrode material.

A fourth aspect of the present invention provides a method for manufacturing a semiconductor device having a first contact hole and a second contact hole deeper than the first contact hole. A step of forming one of the second contact holes, a step of selectively growing an electrode material in the one contact hole, a step of forming a selective growth prevention film on the electrode material, and a step of forming the other contact hole. and selectively growing an electrode material in the other contact hole.
1st. Both second contact holes are filled with electrode material uniformly.

[Conventional technology]

Technological advances in the field of semiconductor device manufacturing have been remarkable, and many new methods have been developed.

One such technique is the selective growth of conductive materials. An example of such a technique is one that utilizes a tungsten selective CVD method for filling and planarizing contact holes. Such selective growth technology can selectively form a specific conductive material on a substrate made of a specific material, and can be effectively used in the manufacture of semiconductor devices, which are becoming increasingly finer and more integrated. It will be done.

Regarding the selective tungsten CVD method, in a normal process, tungsten grows selectively only on silicon, and tungsten does not adhere to silicon dioxide, so it is used as a flattening technique to fill in contact holes formed on silicon. It can be said to be excellent.

However, in the selective growth technology of conductive materials, the growth rate when the materials are selectively grown is almost the same under the same conditions;
There are some problems associated with that.

One is that even if we try to increase productivity by accelerating growth,
That's what makes it difficult. In particular, the selective CVD method for tungsten has a slow growth rate and is difficult to process in a short period of time. In an attempt to increase the selective growth rate, for example, if a layer of material for selectively growing the filling material is formed on the inner wall of the contact hole, the problem arises that the effective diameter of the contact hole becomes smaller, which is not a fundamental solution.

Another problem is that even if it is used to fill two or more openings with different depths, uniform filling cannot be achieved.For example, as shown in FIG. (or more) when contact holes 21, 22 with different depths are opened, the growth rate of the selectively grown material, for example tungsten, is the same;
This will result in the following non-conformities: That is, when the deeper contact hole 22 is completely filled, the filling material 3 (tungsten) overflows into the contact hole 21 as shown schematically in FIG. When completely filled, the contact hole 22 is not completely filled, as schematically shown in FIG. 5(c). With the miniaturization of semiconductor devices, the interlayer film 2 in which contact holes are formed has become flattened, and as a result, multiple contact holes with different depths are often formed, causing the problems described above. has come out.

In FIG. 5, reference numeral 11 indicates a gate electrode made of polysilicon.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional technology, the growth rate of selectively grown materials is almost the same under the same conditions, so it is difficult to increase productivity by increasing the growth rate, and contact holes of different depths are difficult to increase. There were problems that needed to be solved, such as when there were two or more, it was not possible to embed them all uniformly.

An object of the present invention is to provide a method for manufacturing a semiconductor device that solves the above problems.

[Means and effects for solving the problems] In order to achieve the above object, the invention according to claim 1 of the present invention has at least two first. A first contact hole for the first semiconductor region and a second contact hole for the second semiconductor region that is deeper than the first contact hole are formed in the insulating film formed on the second semiconductor region. A method for manufacturing a semiconductor device comprising the steps of: forming a base conductive layer on at least the sidewall of the second contact hole on which an electrode material can be selectively grown; The method includes a step of selectively growing an electrode material in the second contact hole at the same time.

An embodiment of the invention according to claim 1 is shown in FIG.
Using this, the configuration of the present invention will be briefly described as follows.

In the present invention, at least two first . A first contact hole 21 for the first semiconductor region 11 in the insulating film 2 formed on the second semiconductor region 11.12,
A second contact hole 22 for the second semiconductor region 12 is formed deeper than the first contact hole 21, but in the embodiment shown in FIG. A contact hole 22 is formed (FIG. 1(a)), and then a base conductive layer 4 on which an electrode material can be selectively grown is formed on at least the side wall of the second contact hole 22 (FIG. 1(b)). ), then the first contact hole 21 is formed (FIG. 1(c)), and then the first contact hole 21 is formed (FIG. 1(c)). Electrode materials 31.32 are simultaneously selectively grown in the second contact holes 21.22 to obtain a buried structure as illustrated in FIG. 1(d).

The effect of the invention according to claim 1 is as follows.

In this invention, since the base conductive layer 4 on which the electrode material can be selectively grown is formed in the second contact hole 22, which is the deeper hole, at least on the side wall thereof, the electrode materials 31 and 32 can be grown at the same time. When selectively grown, the growth rate of the electrode material 32 in the second contact hole 22 becomes faster. Therefore, as a result, the first. Uniform filling is achieved in the second contact holes 21,22.

Next, the invention according to claim 2 of the present application includes a step of forming a contact hole in an insulating film formed on a semiconductor region;
a step of selectively forming a metal nitride film on the bottom surface of the contact hole; a step of forming a base conductive layer on which an electrode material can be selectively grown in the contact hole and on the insulating film; The method includes the steps of performing anisotropic etching with a selectivity relative to the metal nitride film to leave the base conductive layer on the side wall of the contact hole, and selectively growing an electrode material within the contact hole.

An embodiment of the invention according to claim 2 is shown in FIG.
Using this, the configuration of the present invention will be briefly described as follows.

In this invention, a contact hole 21 is formed in an insulating film 2 formed on a semiconductor region 1 (FIG. 2(a)).
A metal nitride film 5 is selectively formed on the bottom surface of the contact hole 21 (FIG. 2(e)). A base conductive layer 6 is formed on the contact hole 21 and on the insulating film 2, on which an electrode material can be selectively grown. 2(f)'), the base conductive layer 6 is anisotropically etched with a selectivity to the metal nitride film 5, leaving the base conductive layer 6 on the side wall of the contact hole. Figure (g)), the above contact hole 2
Electrode material 3 is selectively grown within 1 (FIG. 2(h)).

The effect of the invention according to claim 2 is as follows.

In this invention, since the base conductive layer 6 on which the electrode material 3 can be selectively grown is formed on the side wall of the contact hole 21, the growth of the electrode material 3 can be accelerated, the processing time can be shortened, and the When forming the base conductive layer 6 while leaving it on the side wall of the contact hole 21, the metal nitride film 5 is formed on the bottom surface of the contact hole 21, so the diameter of the contact hole 21 is not substantially changed (in addition, it can be filled in a short time). can be achieved.

Next, the invention according to claim 3 of the present application provides at least two first. A first contact hole for the first semiconductor region formed in an insulating film formed on the second semiconductor region, and a second contact hole for the second semiconductor region that is deeper than the first contact hole. A method for manufacturing a semiconductor device in which a second contact hole is formed, and a second contact hole is filled with an electrode material. a step of selectively growing an electrode material having a thickness substantially equal to the difference in depth of the second contact hole; a step of forming a first contact hole; The method also includes a step of selectively growing an electrode material in the second contact hole at the same time.

An embodiment of the invention according to claim 3 is shown in FIG.
Using this, the configuration of the present invention will be briefly described as follows.

As illustrated in FIG. Insulating film 2 formed on second semiconductor region 11.12
a first contact hole 21 for the first semiconductor region 11 formed in the first contact hole 21;
In the present invention, which is a method for manufacturing a semiconductor device in which a second contact hole 22 for the second semiconductor region deeper than the second semiconductor region is buried with an electrode material, the second contact hole 22 is formed in the second semiconductor region as shown in FIG. 3(a). ), the first . The electrode material 31 having a thickness equal to the difference l in depth between the second contact holes 21 and 22 is selectively grown (Fig. 3(b)), and the first contact hole 21 is formed (Fig. 3(c)). , 1st. At the same time, electrode material 32 is selectively grown in the second contact holes 21 and 22 (FIG. 3(d)).

According to the invention according to claim 3, the deeper second contact hole 22 is buried in advance by the difference l in depth between the first and second contact holes 21 and 22 (((third (see figure (b)), both contact holes 21 and 22
Uniform embedding can be achieved.

Next, the invention according to claim 4 of the present application provides at least two first. A first contact hole for the first semiconductor region formed in an insulating film formed on the second semiconductor region, and a second contact hole for the second semiconductor region that is deeper than the first contact hole. In the method of manufacturing a semiconductor device in which the electrode material is embedded in the first. Second
a step of forming one of the contact holes, a step of selectively growing an electrode material in the one contact hole, a step of forming a selective growth prevention film on the electrode material, and a step of forming the other contact hole. and a step of selectively growing an electrode material in the other contact hole.

An embodiment of the invention according to claim 4 is shown in FIG. 4A, and the structure of the invention will be briefly described using this as follows.

That is, the example of FIG. 4A has three contact holes 21, 22.2 with different depths as schematically shown in FIG. 4A (a).
However, in the present invention, one of the first and second contact holes (contact hole 21 in the figure) is formed as illustrated in FIG. 4 (FIG. 4(b)).
, selectively grow an electrode material 31 in one of the contact holes 21 (FIG. 4(c)), and form a selective growth prevention film 7 on the electrode material 31 (FIG. 4A(d)). A contact hole (contact hole 22 in the figure) is formed (FIG. 4(e)), and an electrode material 32 is selectively grown in the other contact hole 22 (FIG. 4(f)).
).

According to the invention according to claim 4, after forming one contact hole 21 and filling it, when filling the other contact hole 22, the selective growth prevention film 7 is applied to the filled contact hole. Since no growth occurs, the respective desired uniform implantation can be achieved.

〔Example〕

Next, examples of each invention of the present application will be described. It should be noted that, as a matter of course, each invention is not limited in any way by the respective embodiments described below.

Example 1 This example embodies the invention according to claim 1 of the present application. When manufacturing a semiconductor device, contact holes of different depths are formed using W (tungsten), which is an electrode material. ) is used for embedding and flattening.

In this example, as shown in the first answer diagram, an insulating film 2 made of 5iCh or the like on a substrate 1 such as a silicon substrate,
Two contact holes 21.2 each with different depths
2 (contact hole 22 is deeper) is formed,
Then, W is selectively grown and embedded. One contact hole 21 is formed on the gate electrode forming the first semiconductor layer 11 (see FIG. 1(d)), and is for forming a contact electrode for this gate electrode 11. The hole 22 is formed in the second semiconductor layer 1
2 (see Figure 1).
In this example, the first semiconductor region 11, which is the gate electrode, can be formed of polysilicon, for example. Further, the second semiconductor region 12, which is a source/drain region, can be formed by introducing appropriate impurities depending on the conductivity type of the substrate 1. It may also have a so-called LDD structure.

In this example, first, a deep layer is formed on the insulating film 2 on the substrate 1 which has the second semiconductor region 12 which is the source/drain region and also has the first semiconductor region 11 which is the gate electrode. Only the contact hole 22 is opened and the first contact hole 22 is opened.
The structure shown in Figure (a) is obtained. That is, the contact hole 22 is formed on the second semiconductor region 12 of the insulating film 2 by appropriate means such as resist coating, resist pattern formation, and etching to form a hole. In the figure, reference numeral 13 is a gate insulating film of 5iOz or the like, and 14 is a sidewall.

Next, in this embodiment, by forming a polysilicon sidewall on the sidewall of the contact hole 22, a base conductive layer is formed on at least the sidewall of the contact hole 22 on which an electrode material (in this case, W) can be selectively grown. 4
form. As a result, the structure shown in FIG. 1(b) is obtained. In this example, the underlying conductive layer 4 can be formed by, for example, performing CVD of polysilicon and etching. Or, JP-A-62-24332
The method described in JP-A No. 5, etc. may be used, JP-A-62-
The method of No. 243325 is to form a thin 5-inch insulating film on the entire surface including the contact hole, and then perform CVD on the entire surface.
, a thin polysilicon film (or W S i z , W, M
A metal or a metal-containing film such as oSMo3iz may also be formed.

Next, a shallower contact hole 21, that is, a contact hole 21 above the gate electrode in this example, is opened, and as shown in FIG.
The structure is c).

Next, hole filling and planarization are completed by W selective CVD method. Selective growth is performed using a gas containing W (tungsten fluoride, etc.)
A common method can be adopted. As a result, the contact holes 21 and 22 are filled with electrode material 31.
The structure shown in FIG. 1(d) in which 32 (W) is embedded is obtained. Since the base conductive layer 4 is formed on the side wall of the contact hole 22, the electrode material 32 grows in this part in about 1 iz compared to the case where the base conductive layer 4 is not attached.
Although the contact holes 21 and 22 themselves have different depths,
Hole filling is achieved uniformly in about the same amount of time.

W selection CVD conditions depend on the specific situation.

You just need to set the most suitable one. That is, the condition settings include the depth of the contact holes 21 and 22 and the ratio between the two, the opening size of each contact hole 21 and 22 and the ratio between the two, and the properties of the underlying material (physical properties of the material of the substrate 1, etc.). Unlike,
In addition, there are different conditions when the gate electrode, which is the first semiconductor region 11, is made of only polysilicon and when at least the surface is made of WSL), depending on the properties of the polysilicon, which is the base conductive layer 4, etc. It can be set optimally.

Although it depends on other conditions, it is generally possible to complete filling a contact hole 22 whose width is twice the depth of the contact hole 21 in the same amount of time.

The present invention can be widely used for filling holes using a metal that can be selectively grown. Not only W and Tt (titanium), but also various other materials that can be selectively grown can be used as the electrode materials 31 and 32.

Various materials can be used for the base of the substrate 1 and the like, and also for the base conductive layer 4, depending on the type of the electrode materials 31 and 32.

Furthermore, as shown in FIG. )
It can be suitably used even when the contact holes 21 and 22 have different depths.

As described above, in this embodiment, when contact holes 21 and 22 having different depths are filled and flattened using a selective CVD method such as W, first the deeper contact holes 21 and 22 are flattened.
2 is opened, and a base conductive layer 4, which is a material on which an electrode material (W) such as polysilicon grows, is formed on the side wall of the contact hole 22 in a sidewall shape, and then a shallower contact hole 21 is opened. Both contact holes 21.
This completes uniform hole filling and flattening of No. 22.

According to this embodiment, (1) W is used for contact holes 21 and 22 having different depths.
Uniform hole-filling and planarization can be achieved by selecting electrode materials such as CVD.

(2) Selection of electrode material such as W The time required for CVD is the time required to fill the shallow contact hole 21, making it possible to perform the process in a short time and improve productivity.

(1) There is no need to repeat opening and filling of each contact hole 21 and 22 (the process is completed with one selection CVD).

There is an advantage.

Example 2 This example embodies the invention according to claim 2 of the present application. When manufacturing a semiconductor device, a contact hole with a large aspect ratio is formed using W (tungsten), which is an electrode material. ) is applied when embedding.

In particular, in this embodiment, the contact hole is filled by the tungsten selective CVD method, and at this time, polysilicon is left in the form of a sidewall on the sidewall of the contact, or polysilicon is attached in the form of a sidewall to shorten the filling time. In this case, metal nitride is applied to the silicon substrate 1 before forming the polysilicon sidewall.

In this example, a contact hole 21 is formed in the insulating film 2 to obtain the structure shown in FIG. 2(a), and then Ti (titanium) is formed.
Deposit. As a result, a metal film 51 is formed in FIG. 2 (b).
). Next, annealing is performed so that titanium silicide is formed at the interface between titanium and silicon, which is the substrate 1.

In this way, the structure shown in FIG. 2(c) is obtained. The generated metal silicide layer is indicated by hatching in the figure and reference numeral 52. Then, it was treated with a hydrogen peroxide solution, as shown in Fig. 2(d).
A metal silicide layer 5 is formed at the bottom of the contact hole 21 as shown in FIG.
Create a structure with 2 remaining. Next, the surface of the metal silicide layer 52 is nitrided (sanicidated) by heating in a nitrogen N2 atmosphere to obtain a metal nitride film 5 made of TiN (titanium nitride).

This structure is shown in FIG. 2(e), and in particular, the metal nitride film 5 is
It is schematically shown with double hatching.

After forming the metal nitride film 5 at the bottom of the contact hole 21 as described above, polysilicon is deposited by the CVD method to form a conductive base N6 as shown in FIG. 2(f).
A base conductive layer 6 (polysilicon) is left on the side wall of the contact hole 21 using Esochiba Tsukku. At this time, the second
As shown in Figure (g), the etchback can be stopped at the metal nitride 5.

Next, a selective CVD method is performed using W as the electrode material to complete the hole filling and obtain the structure shown in FIG. 2(h) in which the electrode material 3 is embedded.

Alternatively, it is also possible to leave the resist for forming the contact hole 21 and apply metal (W or the like can be used) to form the metal film 51.

In the prior art, for example, as disclosed in Japanese Unexamined Patent Publication No. 62-243325, there was a method of depositing polysilicon on the side wall of the contact hole to shorten the hole filling time.
In this conventional technique, since SiO□ is attached to the side wall of the contact hole, the diameter of the contact hole becomes substantially small. That is, as schematically shown in FIG. 2', the diameter 12 of embedding W or the like becomes smaller than the contact hole diameter 11, resulting in problems such as an increase in the contact resistance between the W or the like and the substrate. This problem is especially serious because 5LOZ, which is an insulating material, is attached to the side wall of the contact hole.

On the other hand, according to this embodiment, the contact hole 21
By forming the metal nitride film 5 in advance on the bottom of the
The filling can be completed without substantially changing the diameter of the contact hole 21. Uniformity is also improved over the prior art. Furthermore, bond breakdown due to encroachment of W or the like can be prevented. In other words, when growing W, generally W
A gas such as Fb is used, but when reducing this WFh, the generated HF may create a gap around the bottom of the contact hole, or W may enter the bottom of the contact hole or its surroundings, reducing reliability. However, this can be prevented by using nitrides such as TiN, which are less likely to cause encroachment.

In the above embodiment, Ti nitride was used as the metal nitride, but other appropriate metals such as W, Ta, Mo, Hf, etc. can be used.

Example 3 This example embodies the invention according to claim 3 of the present application, and the invention is applied to two or more contact holes having different depths and a large aspect ratio when manufacturing a semiconductor device. This is applied when embedding with electrode material.

As shown in FIG. 3(c), when the glabellar film 2 at the bottom of the wiring layer is flattened, contact holes 21.2 with different depths are formed.
2 may be formed. For example, as shown in the figure, 1. This is the case in which contact holes 21 and 22 are provided above the diffusion regions and gate electrodes forming the second semiconductor regions 11 and 12.

In this case, using the selective CVD method such as W,
When W or the like is grown on a substrate of silicon or the like, as mentioned above, when attempting to fill the deeper contact hole 22 and flatten it, W overflows into the other contact hole 21; Even if the contact hole 22 is filled and flattened, the filling is completely insufficient.

The technique of attaching a polysilicon sidewall only to the deeper contact hole 22 is difficult to achieve if the aspect ratio of both contact holes 21 and 22 is quite large. It is possible that the process will not end. For example, if the contact diameter of the deeper contact hole 22 is 0.5 μm and the contact depth of the other contact hole 21 is 0.5 μm, even if the contact hole 22 is completely buried, the contact diameter of the contact hole 21 is 0.2 μm. The above level difference will occur.

Another possible method is to allow the filling material in the deeper contact hole 21 to overflow (see FIG. 5(b)) and etch it back to flatten it. It is difficult to control this, and the holes tend to become dented even though they must be flattened, making it impossible to use in practice.

The invention according to claim 3 of the present application can effectively fill two or more contact holes with large aspect ratios (and different depths) without causing the above-mentioned problems.

This example is shown in FIG. 3, and this example has a first contact hole 21 on a polysilicon gate electrode, which is a first semiconductor region 11, and a source/drain region 12, which is a second semiconductor region 12. The present invention was applied when the upper second contact hole 22 was formed in the insulating film 2 forming the glabellar membrane, and the third contact hole 23 was further formed. Regarding the depth of the contact holes, the contact hole 22 is the deepest, followed by the contact hole 21, and then the contact hole 23 in that order.

In this embodiment, first, only the deepest contact hole 22 is opened to form the structure shown in FIG. 3(a). Next, this contact hole 22 is filled with electrode material 31 by the depth difference l from the contact hole 21, as shown in FIG.
Do as in b). As a result, the electrode material 31 is filled up to the bottom of the next deepest contact hole 21 . However, it may be buried a little shallower than that.

Next, the next deepest contact hole 21 is opened,
The structure is as shown in FIG. 3 (9).

Next, the difference β′ from the next deepest contact hole 23
At the same time, electrode material 3 is applied to contact holes 21 and 22.
Embed 2. As a result, the structure shown in FIG. 3(d) is obtained.

Next, in the same manner, the contact hole 23 is opened (FIG. 3(e)) and filled to form the electrode material 33 (FIG. 3(e)).
Figure 3(f)). This achieves hole filling and flattening.

In this embodiment, contact holes 21° 22 with different depths are used.
, 23 by selective CVD such as W,
Starting from the deepest contact hole, selective CVD growth of W, etc. is repeated to open the contact hole and reach the bottom of the next deepest contact hole, filling the hole and flattening the hole. Holes can be effectively filled and flattened using a selective CVD method such as W.

When contact holes are opened all at once, since deep ones are opened, shallow ones are subject to considerable over-etching, resulting in damage to shallow contact holes, especially when opening over the gate. On the other hand, according to this embodiment, since the contact holes are opened separately in order of depth, the above-mentioned damage can be limited as much as possible.

Example 4 This example embodies the invention according to claim 4 of the present application, and similarly to Example 3 above, when manufacturing a semiconductor device, two semiconductor devices having different depths and a large aspect ratio are used. This is applied to the case where the above contact hole is filled with an electrode material.

This example also has at least two first
．． A first contact hole 21 for the first semiconductor region formed in an insulating film formed on the second semiconductor region, and a second contact for the second semiconductor region that is deeper than the first contact hole. The contact hole 22 is filled with an electrode material, and further has a contact hole 23 having a depth intermediate between the two, which is also filled, but is shown in a simplified manner in the drawing.

See Figure 4A.

In this embodiment, as schematically shown in FIG. 4A, contact holes 21, 22, .
23 are formed, and these holes are filled with electrode material.

First, contact holes 21, 22. ．． Drill any one of the 23 holes. Here, the first contact hole 21 is first opened as shown in FIG. 4A (b). Next, this contact hole 21 is filled with W as an electrode material 31 by selective CVD and planarized.

Next, a selective growth prevention film 7 made of SiOt is formed on the electrode material 31 by depositing 5 Ioz on the entire surface. This results in the structure shown in FIG. 4A (d).

Next, another contact hole of one depth is opened, but here the second contact hole 22 is opened,
Do as shown in FIG. 4A (e). Next, this contact hole 22 is filled with W by selective CVD and planarized. The resulting structure is shown in FIG. 4A(f). The contact hole 21 is covered with a selective growth prevention film 7 5i.
There is an Oz film, and W does not grow.

Next, the same operation is performed for the contact hole 23 as well.

By sequentially repeating the above operations, contact holes of different depths can be effectively filled and flattened by selective W CVD.

Example 5 Next, Example 5 will be described with reference to FIG. 4B. Like the fourth embodiment, this example also embodies the invention of claim 4, and will be explained using schematic diagrams.

See Figure 4B.

In this embodiment, as schematically shown in FIG. 4B (a), contact balls 21, 22, and 2 having different depths are formed in the insulating film 2.
3 are formed, and the holes are filled with electrode material.

First, any one of the contact holes 21, 22, 23 is bored. Here, first, the first contact hole 21 is opened as shown in FIG. 4B (b).

Next, this contact hole 21 is filled with W as an electrode material 31 by selective CVD and planarized. As a result, the structure shown in FIG. 4B (c) is obtained.

Next, a selective growth prevention film 7 is formed on the electrode material 31 by depositing aluminum over the entire surface.

This results in the structure shown in FIG. 4A (d). When an aluminum film is formed, the surface of the aluminum film undergoes natural oxidation and becomes aluminum oxide, which is generally sufficient to prevent selective growth, but if this is insufficient, oxidation can be performed by ashing or other means. It's okay.

Next, the second contact hole, which is another one depth, is
A contact hole 22 is opened as shown in FIG. 4A (e). Next, a selected CV is formed in this contact hole 22.
W is filled with D and flattened. Since the contact hole 21 has aluminum (or Al2O2) as the selective growth prevention film 7 thereon, W does not grow.

As a result, the structure shown in FIG. 4A (f) is obtained.

Similar to the fourth embodiment, by sequentially repeating this process, hole filling and flattening are realized.

Note that after forming the selective growth prevention film 7, a method of removing aluminum by wet etching can be used to form the contact hole.

For example, aluminum can be removed without affecting W by etching with an aqueous solution containing phosphoric acid or nitric acid. This makes it possible to remove aluminum with less unevenness. Further, if it is better to perform etching after forming a certain layer, such a structure can be adopted without etching each time. Furthermore, even if aluminum remains, A 1
If t O:l is removed, it will not interfere with the electrode material.

In this embodiment, after the entire surface aluminum deposition as shown in FIG. 4B(d), the following may be performed.

■Add heat treatment and apply Af-W compound to contact hole 2
Form with the top of 1.

■Remove Al with phosphoric acid. The Affi-W compound remains.

■Al2O2 on the Al-W surface by Ox ashing etc.
form.

W does not grow on AfzOff. After this, Figure 4A (
The contact hole 22 of e) is opened, and the electrode material 32 is
embedding.

This embodiment is particularly applicable to aluminum films (or Al z
Since the wiring material is used, it can be removed with sufficient selectivity from the insulating film between the eyebrows before applying the wiring material.

〔Effect of the invention〕

As detailed above, with conventional techniques, the growth rate of selectively grown materials is almost the same under the same conditions, making it difficult to increase productivity by increasing the growth rate, and contact holes with different depths. However, according to the invention of the present application, such problems can be solved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing Example-1 in the order of steps. FIG. 1' is a sectional view for explaining a modified application example for coughing. FIG. 2 is a sectional view showing Example 2 in the order of steps. FIG. 2' is a sectional view showing the problem to be solved and explaining the operation of the second embodiment. FIG. 3 is a cross-sectional view showing the steps of Example-3. FIG. 4A is a sectional view showing Example 4 in the order of steps. FIG. 4B is a sectional view showing Example-5 in the order of steps. FIG. 5 is a sectional view for explaining the problems of the conventional example. ■...Semiconductor region (substrate), 2...Insulating film, 11.
...first semiconductor region (gate electrode), 12...second
semiconductor region (source/drain region), 21... contact hole (first contact hole), 22...
・Second contact hole, 3, 31.32.33・
...Electrode material, 4.6... Base conductive layer, 5... Metal nitride film, 7... Selective growth prevention film.

Claims (1)

[Claims] 1. An insulating film formed on at least two first and second semiconductor regions has a first contact hole for the first semiconductor region and a deeper contact hole than the first contact hole. A method for manufacturing a semiconductor device comprising the step of forming a second contact hole for the second semiconductor region, the step of forming a base conductive layer on at least the sidewall of the second contact hole, on which an electrode material can be selectively grown. A method for manufacturing a semiconductor device, comprising: simultaneously selectively growing an electrode material in the first and second contact holes. 2. A step of forming a contact hole in the insulating film formed on the semiconductor region, a forming step of selectively forming a metal nitride film on the bottom surface of the contact hole, and a step of forming an electrode material in the contact hole and on the insulating film. a step of forming a base conductive layer that can be selectively grown; a step of anisotropically etching the base conductive layer with a selectivity to the metal nitride film to leave the base conductive layer on the side wall of the contact hole; A method for manufacturing a semiconductor device, comprising the step of selectively growing an electrode material in a contact hole. 3. A first contact hole for the first semiconductor region formed in an insulating film formed on at least two first and second semiconductor regions, and a second contact hole deeper than the first contact hole. In a method for manufacturing a semiconductor device in which a second contact hole for a semiconductor region is filled with an electrode material, forming the second contact hole;
a step of selectively growing an electrode material having a thickness substantially equal to the difference in depth between the first and second contact holes in the second contact hole; a step of forming the first contact hole; Second
A method for manufacturing a semiconductor device, comprising the step of simultaneously selectively growing an electrode material in a contact hole. 4. A first contact hole for the first semiconductor region formed in an insulating film formed on at least two first and second semiconductor regions, and a second contact hole deeper than the first contact hole. A method for manufacturing a semiconductor device in which a second contact hole for a semiconductor region is filled with an electrode material, comprising the steps of forming one of the first and second contact holes, and selectively growing an electrode material in the one contact hole. manufacturing a semiconductor device comprising: a step of forming a selective growth prevention film on the electrode material; a step of forming another contact hole; and a step of selectively growing an electrode material in the other contact hole. Method.