JP3289479B2 - Method for CVD of refractory metal layer and method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to CVD of a refractory metal layer.
Method and, for example, forming electrodes, wiring, etc. with a refractory metal layer
The present invention relates to a method for manufacturing a semiconductor device to be formed .

[0002]

2. Description of the Related Art As the degree of integration and performance of semiconductor devices such as LSIs increase, the proportion of the area occupied by wiring portions on a semiconductor chip tends to increase. In order to avoid an increase in the semiconductor chip area due to this, an interlayer connection using a multilayer wiring and a contact electrode is an essential process. Conventionally, as an electrode / wiring forming method, A
It has been widely practiced to form 1 and Al alloys by sputtering. However, as described above, in a situation where the wiring is multi-layered, and as a result, the surface step of the semiconductor substrate and the aspect ratio of the connection hole are becoming remarkable, the conventional method using sputtering has a step coverage. Insufficient connection or disconnection due to lack has become a serious problem.

In recent years, various selective CVD methods have been proposed in which a high-melting point metal layer such as W, Mo, Ta, or the like, or a metal such as Al, an Al alloy, or Cu is selectively grown and embedded in a connection hole. In the selective CVD, a source gas such as a metal halide, a metal carbonyl, an organometallic compound, or the like is reduced by a lower wiring material exposed at the bottom of the connection hole to selectively deposit a constituent metal in the connection hole. . However, in the case of the selective CVD, the selectivity gradually deteriorates as the number of batches increases, and tends to deposit on an undesired portion such as on an interlayer insulating film. In addition, there is an unsolved problem such as poor controllability of etch-back removal of an overgrown portion on a connection hole called a nail head, and at present it has not yet reached a practical level.

[0004] In view of the above situation, an electrode / electrode by blanket CVD is being reviewed instead of selective CVD.
This is a wiring forming method. Blanket CVD is so named because it does not depend much on the chemical nature of the underlying growth surface and is deposited without selectivity over the entire surface of the underlying substrate. As an example, by covering the entire surface of the interlayer insulating film in which the connection hole is opened,
A typical example is a process in which a high-melting-point metal layer such as W is formed flat so as to fill this connection hole. A general commentary article on filling W contact holes by blanket CVD can be found in, for example, Monthly Semiconductor World Magazine (Press Journal), November 1990, 2
See page 20.

[0005]

The refractory metal layer of W or the like formed by blanket CVD has poor adhesion to an interlayer insulating film made of SiO ₂ or the like.
An adhesion layer made of a Ti-based material layer such as N is formed as a base, and a refractory metal layer is formed thereon. These adhesion layers may also serve as barrier metal layers. Although the adhesion layer is formed by sputtering, it is difficult to conformally adhere the adhesion layer inside the connection hole having a large aspect ratio by sputtering. For this reason, there is a portion that is not attached to the lower portion of the side surface of the connection hole, or conversely, it is attached in an overhang shape to the upper portion of the side surface of the connection hole.

Due to the lack of step coverage of the adhesion layer, voids may be generated in the contact plug of the blanket CVD high melting point metal layer formed on the upper layer.
This problem will be described with reference to FIGS.

FIGS. 6 (a) to 6 (c) are views showing problems in filling connection holes with W by conventional blanket CVD. First, as shown in FIG. 6A, when a TiN layer 5 is deposited by sputtering on a substrate to be processed in which a connection hole 3 having a large aspect ratio is opened in an interlayer insulating film 2 on a semiconductor substrate 1, FIG. As shown in ()), the insulating film 5 is formed with a uniform thickness on the interlayer insulating film 5, but there is a portion that is not adhered to the lower portion of the side surface of the connection hole 3, or conversely, an overhang is formed on the upper portion of the side surface of the connection hole 3. Be deposited. From this state, a high melting point metal layer 6 such as W is deposited by blanket CVD.
As typical blanket CVD conditions, first, WF ₆ 25 sccm SiH ₄ 10 sccm gas pressure 1.1 × 10 ⁴ Pa W nuclei are formed for 20 seconds under conditions of SiH ₄ reduction at a substrate temperature of 475 ° C. At this time, a method is adopted in which only SiH ₄ alone is first advanced into the CVD chamber, a few atomic layers of SiH ₄ are adsorbed on the growth surface, and then WF ₆ is mixed to favorably form W growth nuclei. In some cases. Thereafter, by switching the WF ₆ 60 sccm H ₂ 360 sccm gas pressure 1.1 × 10 ⁴ Pa H ₂ reducing conditions of the substrate temperature of 475 ° C. to deposit a W layer. At this time, as shown in FIG. 6C, the refractory metal layer 6 grows following the overhanging shape of the TiN layer 5, so that a void 7 is generated. The interlayer insulating film 2 is partially exposed at the lower part of the side surface of the connection hole 3, and the nucleus growth of W hardly occurs on this exposed surface, so that the high melting point metal layer 6 is hardly grown, which also promotes the generation of the void 7.

The refractory metal layer 6 is thereafter etched back to form a contact plug.
Is exposed and a deep step occurs. This is partly because the joint of the growth surface of the refractory metal layer 6 indicated by a broken line above the void 7 has a higher etching rate than the other parts of the refractory metal layer 6. Thereafter, when an upper Al wiring layer is further formed by sputtering or the like, a step break occurs, and the reliability of a semiconductor device having a multilayer wiring structure is impaired.

The surface morphology of the refractory metal layer 6 by blanket CVD is generally not good.
It has irregularities as shown in FIG. This is because the refractory metal layer 6 grows as a columnar crystal starting from the growth nucleus on the base. This surface morphology tends to be transferred to the surface of the contact plug or the surface of the interlayer insulating film even after the etch-back, and tends to remain on the surface. Therefore, the surface morphology of the upper Al wiring is affected. A problem such as irregular reflection at the time occurs. All of these problems may lead to serious defects in a semiconductor device based on fine design rules such as the sub-half micron class.

[0010] Accordingly, an object of the present invention, in the blanket CVD method of the refractory metal layer, can be embedded without occurrence of voids to the connection hole having a high aspect ratio, to provide a good CVD how the step coverage is there.

Further object of the present invention is to provide a CVD how refractory metal layer having a smooth surface excellent surface morphology.

Another object of the present invention is to provide a blanket C
Having electrodes and wiring by a refractory metal layer using VD,
An object of the present invention is to provide a method for manufacturing a highly reliable semiconductor device. Problems other than the above of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

SUMMARY OF THE INVENTION The present invention provides a method for forming a high melting point metal layer and a method for manufacturing a semiconductor device, which are proposed to solve the above-mentioned problems. After the nucleus of the high melting point metal is formed by the method, the high melting point metal layer is formed by the plasma CVD method while applying an RF bias to the substrate to be processed. Further, according to the CVD method for a refractory metal layer and the method for manufacturing a semiconductor device of the present invention, a substrate to be processed having a connection hole formed therein
Of high melting point metal by plasma CVD without bias
After the nuclei are formed, a high melting point metal layer is formed by a plasma CVD method while applying an RF bias to the substrate to be processed to fill the connection holes. At this time, 1 × 10 ¹¹ / c
It is desirable to form a high melting point metal layer using a plasma CVD apparatus capable of obtaining a plasma density of m ³ or more and less than 1 × 10 ¹⁴ / cm ³ . In addition, it is desirable that after the substrate to be processed is subjected to a pre-sputtering treatment with a rare gas in a chamber of the same plasma CVD apparatus, a high-melting-point metal layer is continuously formed.

Further, the present invention provides a CVD apparatus for a refractory metal layer.
Is 1 × 10¹¹/ Cm^ThreeMore than 1 × 10 ¹⁴/ Cm^ThreeLess than
With a plasma source that can provide plasma density
With RF bias applying mechanism to substrate to be processed
It has. Such a high-density plasma source
As a plasma CVD apparatus having
Type ECR (Electron Cyclotron)
Resonance) Plasma CVD equipment, ICP (I
nductively Coupled Plasma
a) CVD equipment, TCP (Transformer)
Coupled Plasma) CVD equipment, Helicon
Wave Plasma (Helicon Wave Plasma)
a) A CVD apparatus and the like can be exemplified. These plasma processing equipment
The location is 1 × 10¹¹/ Cm^ThreeMore than 1 × 10¹⁴/ Cm^ThreeLess than
High-density plasma can be generated.
There is an advantage that Zuma CVD can be performed. Each of the above
Technical descriptions of high-density plasma processing equipment
It is omitted because it is described in detail in the technical report etc.
As a theory, Monthly Semiconductor World Magazine 1992 January 1
It appears on page 59 of the January issue.

[0015]

The point of the present invention is that the source gas of the blanket CVD of the refractory metal layer is plasma-dissociated into active species to form a film by plasma CVD. Conventional blanket CVD is performed at 400 to 500 ° C. as described above.
In the temperature range. Therefore, the probability of adsorption of the source gas, such as SiH ₄ or WF _{6, on} the growth surface determines the growth nucleation of W and the deposition rate. For this reason, when the adhesion layer such as the TiN layer is formed in an overhang shape, the amount of diffusion and adsorption of the source gas into the connection hole having a high aspect ratio decreases, and the formation of growth nuclei becomes insufficient. As a result, growth in the lateral direction inside the connection hole is hindered, resulting in voids.

In the present invention, plasma dissociation of a source gas,
In particular, active species containing high-energy ions and radicals, such as WF _x and SiH _x, are efficiently generated using dissociation by high-density plasma, and the mobility, adsorption probability, and reactivity to the growth surface inside the connection hole are high. And the formation of growth nuclei and the deposition rate are made uniform.

In addition to the above effects, it is possible to correct the overhang shape of the Ti-based adhesion layer by performing sputtering with a rare gas such as Ar as a pretreatment for blanket CVD, and to simultaneously perform dry cleaning inside the connection hole. Becomes In addition, during blanket CVD, by applying an RF bias to the substrate to be processed, the overhang shape is alleviated and the step coverage is improved while migrating by sputtering of the refractory metal layer during film formation. Since these processes can be continuously performed in the same chamber, contamination of the substrate to be processed is minimized, and the effect of improving ohmic properties is also achieved.

Also, surface migration is induced by the ion sputtering effect during the formation of the refractory metal layer, so that the surface morphology is improved and a smooth refractory metal layer surface can be obtained.

The second point of the present invention is the structure of the plasma CVD apparatus for performing the plasma CVD of the high melting point metal layer. That is, 1 × 10 ¹¹ / cm ³ or more and 1 × 10 ¹⁴
By using a plasma CVD apparatus capable of generating high-density plasma of less than about / cm ³ and applying a substrate bias, a high-melting-point metal layer having excellent step coverage and improved surface morphology is formed.

Conventionally, a parallel plate type plasma CVD apparatus generally used conventionally has a plasma density of 1 × 10 ⁹ / cm ³ , and even a parallel plate type magnetron CVD apparatus using a magnetic field also has a 1 × 10 ⁹ / cm ^3. The plasma density is on the order of 10 ¹⁰ / cm ³ , and has some difficulties in terms of plasma density and source gas dissociation efficiency. However, if a substrate bias is separately applied, it can be used in accordance with the gist of the present invention.

On the other hand, the upper limit of the plasma density is closely related to the etching gas pressure, and is 10 ^-1 which is the main operating pressure of the high-density plasma CVD apparatus used in the present invention.
Pa to 10 ⁰ In Pa range of gas pressure, 1 × 10 ¹⁴
/ Cm ³ is a value close to almost complete dissociation.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 In this embodiment, a connection hole opened to an impurity diffusion layer formed on a semiconductor substrate such as Si is buried with W formed by a substrate bias applying type ECR plasma CVD apparatus. It is. First, a schematic configuration example of a substrate bias application type ECR plasma etching apparatus used in the present embodiment will be described.
This will be described with reference to FIG. In the same device, the microwave of 2.45 GHz generated by the magnetron 15 is
It is introduced into a plasma generation chamber 18 through a microwave waveguide 16 and a microwave introduction window 17 made of quartz or the like, and interacts with a 0.0875 T magnetic field excited by a solenoid 19 disposed around the plasma generation chamber. By the action, the high-density plasma 10 of the source gas is generated in the plasma generation chamber 18. The substrate 11 to be processed is a substrate heating means 13 such as a heater.
Is mounted on the substrate stage 12 having the built-in. Reference numeral 14 denotes an RF bias power supply for supplying a substrate bias, and reference numeral 20 denotes a plasma CVD chamber. The details of the source gas introduction hole, the vacuum exhaust system, and other details are omitted.

Next, the plasma CVD method of the present invention will be described with reference to FIGS. 1 (a) to 1 (c). In addition,
In this figure, the same parts as those described with reference to FIG. 5 are denoted by the same reference numerals, and overlapping description thereof will be partially omitted.

First, as an example, as shown in FIG. 1A, an interlayer insulating film 2 of SiO ₂ or the like is formed on a semiconductor substrate 1 of Si or the like on which an impurity diffusion layer (not shown) is formed in advance. A connection hole 3 facing the layer is opened. The thickness of the interlayer insulating film 2 is, for example, 0.7 μm, and the opening diameter of the connection hole 3 is 0.35 μm.

Next, a Ti layer 4 and a TiN layer 5 as an adhesion layer and a barrier metal layer are deposited on the entire surface by sputtering in this order. In this embodiment, in order to improve the coverage inside the connection hole 3, a sputtering device having a built-in collimator for aligning the flow of the sputtered particles was used. However, as shown in FIG. 1B, a slight overhang was observed. The thickness of each of the Ti layer 4 and the TiN layer 5 is, for example, 35 nm. The sample formed so far is used as a substrate to be processed.

The substrate to be processed is set on the substrate stage 13 of the above-described substrate bias applying type ECR plasma etching apparatus, and a sputtering pretreatment with Ar is performed for 15 seconds under the following conditions. Ar 10 sccm Gas pressure 0.5 Pa Microwave power 1000 W (2.45 GHz) RF bias power 30 W (13.56 MH)
z) Substrate temperature: 300 ° C. In this pretreatment step, a cleaning effect by removing a natural oxide film and the like on the surface of the base material layer, and an overhang portion of the Ti layer 4 and the TiN layer 5 above the connection hole 3 are removed by sputtering. The effect of correcting the shape is obtained.

Continuously, the nucleation of W was 45
Perform for seconds. WF₆ 5 sccm SiH_Four 3 sccm Gas pressure 0.2 Pa Microwave power 1000 W (2.45 GHz) RF bias power 0 W Substrate temperature 300 ° C. This process is a low gas pressure, no bias processing condition
The interlayer insulating film 2 etc. is F ^*Prevents erosion
It is. In this step, the growth nuclei of W are evenly distributed on the substrate to be processed.
Coverage for the next step of forming the high melting point metal layer
And important steps that affect film quality. Note that this
SiH before treatment_FourOnly flow first,_xSucking
The deposition layer may be formed on the entire surface of the substrate to be processed.

Subsequently, under the following conditions, plasma CVD of the refractory metal layer is performed for 90 seconds. WF ₆ 60 sccm H ₂ 200 sccm Gas pressure 1.0 Pa microwave power 2000 W (2.45GHz) RF bias power 10 W substrate temperature 300 ° C. The present process is a main plasma CVD process, using the sputtering by ion Thus, the embedding of the refractory metal layer 6 into the connection hole 3 is completed as shown in FIG. 1C, while suppressing the growth of the overhang portion and the surface irregularities. No void was found at the plug portion of the refractory metal layer 6 in the connection hole 3, and a blanket W having excellent surface smoothness was formed.

Embodiment 2 This embodiment is an example in which a high melting point metal layer is formed by a substrate bias application type ICP-CVD apparatus.

A schematic configuration of a plasma CVD apparatus used in the present embodiment will be described with reference to FIG. In FIG. 3, parts performing the same functions as those in FIG. 2 are denoted by the same reference numerals, and a description thereof will be partially omitted. An ICP power source 21 is provided by an inductive coupling coil 22 wound around a side wall of a plasma CVD chamber 20 made of a dielectric material such as quartz.
Is supplied into the plasma CVD chamber 20 to generate the high-density plasma 10 therein. Illustration of details such as a source gas introduction hole and a vacuum exhaust system is omitted. The feature of this device is that large-sized multi-turn inductive coupling coil 22 enables plasma excitation with high power and 10 ¹² / c
That is, processing with high-density plasma of m ³ units can be performed.

Next, the description will proceed to the plasma CVD method of this embodiment. The substrate to be processed used in the present embodiment is the same as that of the first embodiment, and will be described with reference to FIG. 1, and redundant description will be omitted. The substrate to be etched shown in FIG. 1B is placed on a substrate stage 16 of a substrate bias application type ICP-CVD apparatus, and as an example, a sputtering pretreatment with Ar is performed for 15 seconds under the following conditions. Ar 10 sccm Gas pressure 0.5 Pa ICP power supply power 1000 W (2 MHz) RF bias power 30 W (800 kHz) Substrate temperature 300 ° C. In this pretreatment step, a cleaning effect by removing a natural oxide film or the like on the surface of the base material layer; The overhanging portions of the Ti layer 4 and the TiN layer 5 above the connection holes 3 are removed by sputtering, and an effect of correcting the overhang shape can be obtained.

Continuously, the nucleation of W is uniformized for 30 seconds under the following conditions. SiH ₄ 3 sccm Gas pressure 0.2 Pa ICP power: 1000 W (2MHz) adsorption of RF bias power 0 W entire surface SiH _x of the substrate surface at a substrate temperature of 300 ° C. This step by the flow of SiH ₄ alone Forming several layers,
It enhances the surface affinity with F ₆ and improves the uniformity of W nucleation in the next step.

Subsequently, nucleation of W is performed for 45 seconds under the following conditions. WF ₆ 5 sccm SiH ₄ 3 sccm Gas pressure 0.2 Pa ICP power: 1000 W (2MHz) RF bias power 0 W growth nuclei of uniform W in the adsorption layer of SiH _x at a substrate temperature of 300 ° C. The present process is formed Is done.

Further, the initial growth of the refractory metal layer is performed for 20 seconds under the following conditions. WF ₆ 25 sccm H ₂ 500 sccm Gas pressure 2 Pa ICP power supply power 1000 W (2 MHz) RF bias power 10 W (800 kHz) Substrate temperature 300 ° C. In the initial growth process, the WF ₆ flow rate is suppressed and H ₂ flows in large quantities. As a result, excessive F ^* is consumed, and a thin W layer is formed conformally while preventing erosion of the base.

Further, the following conditions are continuously changed, and main plasma CVD is performed for 90 seconds. WF ₆ 60 sccm H ₂ 200 sccm Gas pressure 1.0 Pa ICP power supply 2000 W (2 MHz) RF bias power 10 W Substrate temperature 300 ° C. This is a main film forming process, and is performed using ion sputtering. The embedding of the refractory metal layer 6 in the connection hole 3 is completed as shown in FIG. 1C, while suppressing the growth of the hang portion and the surface irregularities. No void was found at the plug portion of the refractory metal layer 6 in the connection hole 3, and a blanket W having excellent surface smoothness was formed.

In the present embodiment, the growth nuclei of W on the substrate to be processed are uniformly generated by adding the SiH ₄ single flow process and the initial growth step of the refractory metal layer, thereby providing a more uniform and step coverage. Excellent blanket CVD is achieved and substrate erosion is completely prevented.

Embodiment 3 This embodiment is an example in which a high melting point metal layer is formed by a substrate bias applying type TCP-CVD apparatus.

A schematic configuration example of a TCP-CVD apparatus used in this embodiment will be described with reference to FIG. This apparatus has the same basic configuration as the ICP-CVD apparatus shown in FIG. 3, and the same components are denoted by the same reference numerals and description thereof will be omitted. The feature of this apparatus is that the top plate of the plasma CVD chamber 20 is made of a dielectric material such as quartz, and a spiral TCP coil 24 is disposed on the top surface thereof to introduce the power of the TCP power supply into the plasma CVD chamber 20. It is a point to do. In FIG. 4, details such as a source gas introduction system and a vacuum exhaust system are omitted. According to this device, a large TCP
Due to the inductive coupling between the coil 24 and the source gas in the plasma CVD chamber 20, high-density plasma of the order of 10 ¹² / cm ³ can be generated.

The plasma CVD method of this embodiment is almost the same as the plasma CVD method of the second embodiment. That is, they can be formed in substantially the same manner except that the ICP power supply 21 is replaced with the TCP power supply 23 and the inductive coupling coil 22 is replaced with the TCP coil 24 in the description of the second embodiment. As a result,
As shown in FIG. 1C, blanket CVD of the refractory metal layer 6 was achieved with no void in the plug portion and a smooth surface.

Embodiment 4 This embodiment is directed to a helicon wave plasma CV of a substrate bias application type.
This is an example in which a refractory metal layer is formed by a D apparatus.

An example of a schematic configuration of a CVD apparatus used in this embodiment will be described with reference to FIG. In FIG. 5, components having the same functions as those in FIG. 2 are denoted by the same reference numerals. An electric field generated by supplying electric power to a helicon wave antenna 26 by a helicon wave power supply 25, and a solenoid 19
A whistler wave (helicon wave) is generated in the plasma generation chamber 18 by the interaction with the magnetic field formed by the above, and the high-density plasma 10 of the source gas supplied to the plasma CVD chamber 20 from a gas inlet (not shown) is generated.
27 is a multipole magnet disposed around the plasma CVD chamber,
It generates a magnetic field to be confined in the chamber 20. A substrate bias is applied from a RF bias power supply 14 to a substrate stage 12 on which the substrate 11 to be processed is mounted. According to this device,
Due to the structural characteristics of the helicon wave antenna, it is possible to obtain a higher plasma density of the order of 10 ¹³ / cm ³ than in the above embodiments.

The plasma CVD method according to the present embodiment is also basically the same as the plasma CVD method according to the second embodiment. The ICP power supply 21 in the description of the second embodiment is used as the helicon wave power supply 25, and the inductive coupling coil 22 is used as the helicon wave power supply. It can be formed almost in the same manner except that the wave antenna 26 is replaced. As a result, as shown in FIG. 1C, blanket CVD of the refractory metal layer 6 was achieved with no void in the contact plug portion and with a smooth surface property.

According to this embodiment, the source gas can be more efficiently dissociated by the plasma having a higher density than the previous embodiment, and a uniform film thickness and a good step coverage can be obtained on a large area substrate having a diameter of 8 inches or more. Blanket C with combined properties
VD can be applied.

Although the present invention has been described with reference to the four embodiments, the present invention is not limited to these embodiments.

For example, the process of forming a contact plug by embedding a refractory metal layer in a connection hole has been described in the embodiments, but the embedding process in a via hole formed in an interlayer insulating film on a lower wiring is described. May be applied. If it is applied not only to connection plugs but also to the formation of various electrodes and wiring using blanket CVD,
A good process with a smooth surface can be achieved.

Although the high melting point metal layer 5 is exemplified by W,
Other high melting point metals such as o and Ta may be used. The adhesion layer and the barrier metal layer are exemplified by Ti / TiN.
N, TiW, TiSi _x, etc., may be appropriately selected various materials depending on the material of the base and the refractory metal layer.

Although Ar is exemplified as the rare gas, He, N
Noble gases such as e, Kr and Xe may be used alone or in combination.

As an etching apparatus, a substrate bias application type ECR plasma CVD apparatus, an ICP-CVD apparatus,
Although the TCP-CVD apparatus and the helicon wave plasma CVD apparatus are illustrated, a parallel plate type plasma CVD apparatus or a batch type plasma CVD apparatus such as a hexode type may be used. That is, the effects of the present invention can be enjoyed by employing a structure in which a substrate bias is applied even in plasma CVD using a plasma density of less than 1 × 10 ¹¹ / cm ³ .

Further, the frequencies of 13.56 MHz and 800 kHz are exemplified as the RF power source for applying the substrate bias, but the present invention is not limited to these frequencies.

[0051]

As is apparent from the above description, in the present invention, in the blanket CVD method for a high melting point metal layer, a large aspect ratio is obtained by depositing a substrate to be processed by a plasma CVD method while applying an RF bias to a substrate to be processed. It is possible to embed W or the like without generating a void even in the inside of a fine connection hole.

In addition, since the surface morphology of the refractory metal layer formed by blanket CVD can be improved and a smooth surface can be obtained, unevenness is not transferred to the base or contact plug surface even in the subsequent etch-back step. Further, the shape controllability of the patterning of the upper wiring layer laminated thereon is also improved.

Further, as compared with a conventional blanket CVD process using a thermal decomposition CVD method, the process temperature can be reduced, and a process such as embedding in a via hole on an Al or Al alloy wiring can be performed. This has the effect of expanding the range of choices.

Further, if plasma CVD is continuously performed after performing the pre-sputtering treatment of the substrate to be processed in the same plasma CVD chamber, the effect of correcting the shape of the overhang portion of the adhesion layer and the barrier metal layer and the natural oxide film cleaning effect is obtained equal, step coverage improvement in the effect of improvement of ohmic also obtained.

Each of the above effects is 1 × 10 ¹¹ / cm ³ or more.
If a plasma CVD apparatus capable of obtaining a plasma density of less than × 10 ¹⁴ / cm ³ is used, the effects can be further enhanced.
Door can be.

In order to perform the plasma CVD method of the present invention, a substrate bias application type ECR (Electro-Electro) having a structure provided with an RF bias application mechanism to a substrate to be processed is provided.
n Cyclotron Resonance) plasma CVD apparatus, ICP (Inductively Co)
coupled Plasma) CVD equipment, TCP (Tr
anceformer Coupled Plasm
a) CVD equipment, helicon wave plasma (Helicon)
By using a Wave Plasma) CVD apparatus or the like, a blanket CVD process using high-density plasma of 1 × 10 ¹¹ / cm ³ or more and less than 1 × 10 ¹⁴ / cm ³ can be achieved.

With the above effects, a multilayer wiring process using a high melting point metal layer such as W, including the deposition of a blanket CVD film and its etch-back, can be put to practical use with high reliability. The contribution to the manufacturing process of a semiconductor device or the like based on this is large.

[Brief description of the drawings]

FIG. 1 shows Examples 1, 2, 3, and 4 to which the present invention is applied.
FIGS. 3A and 3B are schematic cross-sectional views illustrating the steps in the order of steps, wherein FIG.
(B) shows a state where an adhesion layer and a barrier metal layer are sequentially sputtered, and (c) shows a state where a high melting point metal layer is deposited on the entire surface by a plasma CVD method.

FIG. 2 is a schematic sectional view of a substrate bias application type ECR plasma CVD apparatus used in Example 1 to which the present invention is applied.

FIG. 3 is a schematic sectional view of a substrate bias application type ICP-CVD apparatus used in Example 2 to which the present invention is applied.

FIG. 4 is a schematic sectional view of a substrate bias applying type TCP-CVD apparatus used in a third embodiment to which the present invention is applied.

FIG. 5 is a schematic sectional view of a substrate bias application type helicon wave plasma CVD apparatus used in Example 4 to which the present invention is applied.

6A and 6B are diagrams for explaining a problem of a conventional blanket CVD method, wherein FIG. 6A shows a state in which a connection hole is opened in an interlayer insulating film on a semiconductor substrate, FIG. c) shows a state in which a refractory metal layer is deposited on the entire surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Interlayer insulating film 3 Connection hole 4 Ti layer 5 TiN layer 6 Refractory metal layer 7 Void 10 High density plasma 11 Substrate to be processed 12 Substrate stage 13 Substrate heating means 14 RF bias power supply 15 Magnetron 16 Microwave waveguide 17 Microwave introduction window 18 Plasma generation chamber 19 Solenoid 20 Plasma CVD chamber 21 ICP power supply 22 Inductive coupling coil 23 TCP power supply 24 TCP coil 25 Helicon wave power supply 26 Helicon wave antenna 27 Multipole magnet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/44 H01L 21/205 H01L 21/285 301 H01L 21/768

Claims (12)

(57) [Claims] 1. A plasma C without bias on a substrate to be processed.
A method for forming a high melting point metal layer, comprising: forming a high melting point metal nucleus by a VD method; and then forming a high melting point metal layer by a plasma CVD method while applying an RF bias to the substrate to be processed. 2. 1 × 10 ¹¹ / cm ³ or more and 1 × 10 ¹⁴ / c
with a plasma CVD apparatus m ³ less than the plasma density can be obtained, and forming the refractory metal layer, CVD method of the refractory metal layer according to claim 1, wherein. 3. The CVD method for a high melting point metal layer according to claim 1, wherein a nucleation uniforming process is performed on the substrate to be processed before forming the high melting point metal nucleus. 4. The step of forming the high melting point metal layer in two stages of initial growth and main growth, wherein the flow rate and the flow rate of the raw material gas of the high melting point metal in the reaction gas during the initial growth are determined by the main growth. 2. The CV of the refractory metal layer according to claim 1, wherein the flow rate and the flow ratio of the source gas of the refractory metal in the reaction gas during the growth of the metal are smaller than the flow rate.
D method. 5. A method for manufacturing a semiconductor device comprising a step of forming a refractory metal layer on a substrate to be processed, comprising: forming a nucleus of a refractory metal on a substrate to be processed by a plasma CVD method without a bias; A method for manufacturing a semiconductor device, comprising forming a refractory metal layer by a plasma CVD method while applying an RF bias to a substrate to be processed. 6. 1 × 10 ¹¹ / cm ³ or more and 1 × 10 ¹⁴ / c
6. The method for manufacturing a semiconductor device according to claim 5, wherein the high-melting-point metal layer is formed using a plasma CVD apparatus capable of obtaining a plasma density of less than m ³ . 7. The method of manufacturing a semiconductor device according to claim 5, wherein a nucleation uniforming process is performed on the substrate to be processed before the nucleus of the refractory metal is formed. 8. The formation of the refractory metal layer in two stages of initial growth and main growth, wherein the flow rate and the flow ratio of the source gas of the refractory metal in the reaction gas during the initial growth are determined by the main growth. 6. The method of manufacturing a semiconductor device according to claim 5, wherein the flow rate and the flow rate ratio of the raw material gas of the high melting point metal in the reaction gas during the growth of the semiconductor are reduced. 9. A substrate having no connection on a substrate to be processed having a connection hole formed therein.
Nucleus of high melting point metal formed by plasma CVD method with EAS
After that, while applying an RF bias to the substrate to be processed,
Forming a refractory metal layer by a plasma CVD method and burying the contact hole;
D method. 10. The method according to claim 1, wherein the nucleus of the refractory metal is formed before
10. The CVD method for a high melting point metal layer according to claim 9, wherein the substrate to be processed is subjected to a nucleation uniformizing process. 11. The method according to claim 1, wherein the connecting hole is formed on the substrate to be processed.
Forming a melting-point metal layer and filling the connection hole.
In the method for manufacturing a semiconductor device according to
After forming the core of the refractory metal, RF
While applying a bias, the above high
Forming the melting hole metal layer and filling the connection hole
A method for manufacturing a semiconductor device. 12. The method of manufacturing a semiconductor device according to claim 11 , wherein a nucleation uniforming process is performed on the substrate to be processed before forming the nucleus of the high melting point metal .