JP2002075912A - Method and device for covering and filling base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for covering and filling a base that can healthily cover and fill the inside of a recess formed on the surface of the base, and has a high deposit speed and at the same time the excellent utilization rate of a raw material. SOLUTION: This device has an ion source required for generating a particle beam (a hydrogen beam 29), a high-speed ion generation mechanism, and a raw material supply mechanism (a raw material container 23 and a carburetor 26) containing the element of a material for covering and filling the inside of the recess formed on the surface of a substrate Wf. The device also has a function for applying the particle beam to the base in parallel with the execution of a normal chemical gaseous phase deposition process and/or before the supply of a feed gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of coating / filling a substrate, in which the inside of the depression having a fine hole or groove formed on the surface is coated / filled by chemical vapor deposition. With respect to the apparatus, in particular, a base material suitable for coating / filling the inside of the recess with a metal material such as copper in a base material in which fine holes or grooves for wiring formed in a semiconductor substrate are formed. The present invention relates to a filling method and an apparatus.

[0002]

2. Description of the Related Art A variety of substrate coating / filling means for coating / filling a fine dent formed on a semiconductor substrate surface have been proposed for the purpose of forming wiring of a semiconductor device, which is increasingly miniaturized and highly integrated in the future. Have been. Among the means for overcoming the limitations of the conventional methods proposed to date, chemical vapor deposition (hereinafter abbreviated as “CVD” as necessary)
Is the only one that can be realized in the future (for example, NIKKEI MICRODEVICES, 19
December 1998, p. 32), research at various institutions
Development is in progress.

FIG. 1 is a diagram showing a schematic configuration example of a coating and filling apparatus for coating and filling copper by CVD. In FIG. 1, reference numeral 1 denotes a reaction chamber, in which a susceptor 2 on which a substrate Wf is mounted is disposed, and the reaction chamber 1 is connected to an exhaust system such as a vacuum pump and has a predetermined pressure P. The pressure is reduced. Reference numeral 3 denotes a raw material container containing a liquid raw material. By supplying a carrier gas from the carrier gas container 4 to the raw material container 3, the liquid raw material is sent to the vaporizer 5 (flow rate f) and vaporized by the vaporizer 5. The raw material gas 6 is supplied into the reaction chamber 1. Note that a heater 7 for heating the semiconductor substrate Wf is provided in the susceptor 2.

In the apparatus for coating and filling a substrate having the above-described structure, a source gas 6 is introduced from a vaporizer 5 into a reaction chamber 1 in which the inside is reduced to a predetermined pressure P, and copper contained in the source gas is deposited on the surface of the substrate Wf. Is dissociated and deposited. Here, as a raw material, an organic complex mainly containing Cu (for example, hexafluoroacetylacetonate / trimethylvinylsilane copper, liquid at room temperature) is used, and the liquid raw material is vaporized by a vaporizer 5 and used. By raising the temperature to 140 ° C. to 180 ° C. to cause a reaction, and depositing copper on the surface of the substrate Wf, copper is formed inside a concave such as a fine hole or groove for wiring of a semiconductor device previously provided on the surface of the substrate Wf. Is deposited and coated or filled.

[0005] Here, covering the inside of the recess with copper is equivalent to forming a base for the subsequent embedding of electrolytic copper plating, that is, a power supply layer. On the other hand, filling copper is not performed by electrolytic plating. This is equivalent to performing consistent embedding for forming the entire wiring by CVD. It is desirable that the above-described respective steps of coating and filling be properly used depending on the degree of miniaturization of the target wiring and the correlation with the entire process.

FIG. 2 is a diagram schematically showing a state of filling with the above-mentioned coating. FIG. 2A shows the case of coating,
A diffusion suppressing layer 13 is formed inside a fine recess 12 formed in an insulating layer 11 of a substrate (not shown), and a deposited copper layer 14 is formed thereon to serve as a power supply layer. FIG.
(B) shows a case of filling, in which a diffusion suppressing layer 1 is formed inside a fine recess 12 formed in an insulating layer 11 of a substrate (not shown).
3 is formed, and the inside thereof is filled with the deposited copper layer 15.

As described above, when the inside of the fine recess 12 on the substrate surface is actually coated and filled with copper CVD, various problems often occur. When the inside of a fine recess having a width of 0.13 μm or less is coated and filled with metallic copper by ordinary CVD, the degree of unevenness of the formed film surface is not only severe (poor morphology), but also the opening of the recess is formed before the inside. As a result of the blockage, defects such as cavities and seams are likely to occur in the portion to be filled, and the copper deposition rate with respect to the raw material consumption is low, and the adhesion between the base material and the deposited copper layers 14 and 15 is weak.

In general, as the degree of integration of a semiconductor device increases, the cross-sectional area of a wiring formed on the semiconductor device and the distance between the wirings tend to decrease more and more. As a result, in the case of a wiring made of aluminum, which is a conventional material, electromigration (EM) caused by a delay in signal transmission and an increase in current density (up to about 1 MA / cm ² or more) due to an increase in electric resistance and line capacitance. Damage is a problem. Therefore, there is an increasing movement to replace the wiring material of conventional aluminum with copper having lower electric resistance.

At present, copper wiring is formed by performing electrolytic copper plating using a thin power supply layer formed by conventional sputtering or the like as a cathode, thereby coating the inside of the fine recess by depositing metallic copper.
This is done by filling. But the line width is 0.13μm
In the following generations, it is difficult to form at least a uniform power supply layer by sputtering deposition. Therefore, it is considered essential to develop and commercialize a method with good embedding property in place of electrolytic plating.

FIG. 3 is a view schematically showing a typical example of a defect which frequently occurs with a copper coating / filling step by CVD. FIG. 3A shows a case where the deposited copper layer 14 is different from a uniform and continuous one as shown in FIG. The cause of this phenomenon is that the activity of the underlying surface is originally low, so the nucleation density of the deposited metal is extremely low, and the tendency for a small number of generated nuclei to grow abnormally large is dominant. It is considered.

An island-shaped deposited copper layer 1 as shown in FIG.
In No. 4, the thickness and volume increase over time and the islands are connected and coalesced, approaching the form of a continuous film-like sediment, but the nucleation density is low and the number of generated islands is low. Because of the small amount, the surface of the deposited copper layer 14 formed after a lapse of a certain time under the influence thereof has severe irregularities, and exhibits a poor morphology. As described above, embedding often becomes a problem even when electrolytic plating is performed on a power supply layer having a significantly uneven surface.

FIG. 3 (b) shows a situation in which an unfilled cavity defect 16 is formed at the center of the dent when a fine dent formed on the surface of the base material is buried with copper by CVD.
The cause of the cavity defect 16 inside the recess 12 is as follows.
Copper layer 1 deposited locally at the entrance of the recess during the filling process
It is presumed that as a result of the increase of 5 and overhanging from both sides and bridging at the entrance, the subsequent flow of copper into the recess is stopped and the supply of copper is stopped.

Since Cu-CVD is usually performed at a pressure of several Torr to several tens Torr, the flow of the gas phase is under the condition of viscous flow. Accordingly, the arrival of the raw material components on the surface of the base material is performed through diffusion through a stagnation layer existing near the base material. It is believed that the formation of a significant raw material concentration gradient in the stagnation layer contributes to the blockage of the inlet portion.

It is known that the deposition rate of copper by CVD is generally much lower than that of sputtering reflow or electrolytic plating. The former has a deposition rate of 200 nm.
/ Min is difficult, but the latter two easily
About 00 nm / min can be obtained.

Further, the adhesion and bonding between the copper deposited layer formed by CVD and the surface of the substrate (the surface of the diffusion suppressing layer 13, for example, the TaN film) is poor. . Poor adhesion / bonding properties are due to lattice mismatch between TaN and Cu and the surface of the TaN layer formed on the substrate surface by ordinary sputtering is oxidized by the action of the surrounding environment thereafter and is covered by the oxide film. It is attributed.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and solves the above-mentioned problems caused by CVD.
An object of the present invention is to provide a method and an apparatus for coating / filling a base material which can be filled, has a high deposition rate, and has a high raw material utilization rate.

[0017]

In order to solve the above-mentioned problems, the invention according to claim 1 is a method for coating / filling the inside of a fine recess provided on the surface of a substrate by a chemical vapor deposition method. In the filling method, the inside of the fine recess provided on the surface of the base material is covered and filled by irradiating the base material with a particle beam in parallel with and / or before the supply of the source gas.

As described above, by irradiating the substrate with the particle beam in parallel with and / or before the supply of the source gas, the density of deposition nuclei generated on the surface of the substrate is dramatically increased. As a result, the surface morphology of the deposit layer deposited on the substrate surface tends to be flat. Further, by adjusting the irradiation intensity of the particle beam so as to change depending on the location of the base material surface, the preferential growth direction of the deposited layer is specified, so that clogging at the dent opening can be avoided to prevent generation of cavity defects. I can do it. At the same time, at the interface between the deposited layer and the substrate surface by increasing the irradiation energy of the particle beam,
Since mixing at the atomic level can be caused, the adhesion between the deposited layer and the substrate can be greatly improved.

According to a second aspect of the present invention, in the method for coating and filling a substrate according to the first aspect, the substrate is irradiated with a particle beam by electron beam or charged particle beam irradiation, atomic beam or molecular beam. It is characterized in that at least one of the line irradiation is performed.

The invention described in claim 3 is the first or second invention.
In the method of coating and filling a substrate according to the above, the substrate is a silicon substrate for manufacturing a semiconductor device, the dent formed on the surface of the substrate is a pattern dent for forming a semiconductor device wiring, and the raw material gas is copper. It is characterized by being an organic complex gas containing.

The invention described in claim 4 is the first or second invention.
In the method of coating and filling a substrate described in the above, when irradiating an ion beam, an atomic beam, or a molecular beam, which is a form of a particle beam, the energy of these beams as particles is set to 200 eV or more and 10 keV or less. It is characterized by.

According to a fifth aspect of the present invention, there is provided an ion source necessary for generating a particle beam, an ion accelerating mechanism, and a raw material supply containing an element of a material for coating and filling the inside of a recess formed on the surface of a substrate. A coating / filling apparatus comprising a mechanism and having a function of irradiating a substrate with a particle beam in parallel with performing a normal chemical vapor deposition process and / or before supplying a raw material gas.

As described above, the ion source, the ion acceleration mechanism,
Since a material supply mechanism is provided so that particle beam irradiation can be performed on the substrate in parallel with the normal chemical vapor deposition process and / or before the supply of the material gas, the surface of the substrate is The surface morphology of the deposit layer deposited on the surface tends to be flat, and the preferential growth direction of the deposit layer is specified to avoid clogging at the opening to prevent the occurrence of cavity defects, The coating / filling apparatus can greatly improve the adhesion between the coating and the filling.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a view showing a schematic configuration example of a coating and filling apparatus by CVD according to the present invention. In FIG. 4, reference numeral 21 denotes a reaction chamber, in which a susceptor 22 for mounting and holding a substrate Wf is disposed, and an exhaust port 32 of the reaction chamber 21 is connected to an exhaust system having a vacuum pump or the like. The connection is made and the pressure is reduced to a predetermined pressure. Reference numeral 23 denotes a raw material container containing a liquid raw material.
Then, by supplying H ₂ gas from the H ₂ storage container 24 via the flow rate controller 25, the liquid raw material is sent to the vaporizer 26, and is vaporized by the vaporizer 26, and is supplied into the reaction chamber 21 as the raw material gas 27. Supply.

Reference numeral 28 denotes a high-speed ion generation mechanism for generating a hydrogen (hydrogen ion H ⁺ , hydrogen radical H ^* , hydrogen molecule H _2, etc.) beam 29 on the substrate Wf mounted and held on the susceptor 22 in the reaction chamber 21. The H ₂ gas is supplied to the high-speed ion generating mechanism 28 from the H ₂ storage container 24 via the flow controller 30. 31 is the susceptor 22
This is a heating / cooling mechanism for heating and cooling the substrate Wf built in the device. The present coating and filling apparatus supplies a raw material gas from an external vaporizer 26 to the reaction chamber 21 and causes a reaction such as decomposition and synthesis of the raw material by an interaction between the raw material gas and the hydrogen beam, thereby forming a desired material on the substrate Wf. This is to deposit copper. The raw material container 23 contains hexafluoroacetylacetonate / trimethylvinylsilane copper C
u (hfac) (tmvs).

FIG. 5 shows the coating and filling apparatus shown in FIG.
Copper film inside fine dents (grooves, holes, etc.) on the surface of f
It is a figure showing the state where it accumulates. FIG. 5A shows a case where the inner surface of the dent is covered with a thin film layer of copper,
This is performed to form a power supply layer indispensable for performing electrolytic copper plating. FIG. 5B shows a case where the inside of the recess is directly filled with copper, which is performed for the purpose of forming an integrated wiring by CVD.

In both cases (a) and (b) of FIG.
First, on the surface of the plate Wf, the raw material Cu (hfac) (tm
vs) 33 is adsorbed and high-speed hydrogen (H⁺,
H^*, H _TwoBy irradiating the beam 29
Energy required for adsorbed Cu (hfac) (tmvs)
Energy and decompose raw materials to form metallic copper deposits
You. The chemical reaction at this time is as shown in equations (1) and (2).
It is assumed that

2Cu ⁺¹ (hfac) (tmvs) adsorption (g) (hydrogen beam energy) → Cu ⁰ (S) + Cu ⁺² (hfac) ₂ (g) +2 tmvs (g) (1) Cu (hfac) + H ^* → Cu + H (hfac) (g) (2) Here, H ^* represents a hydrogen radical.

According to the present invention, since the surface of the substrate Wf is irradiated with the hydrogen beam 29 having a high energy, the diffusion suppressing layer (TaN) 1 is formed at numerous places on the surface of the base material.
3. Break the bonds of the atoms on the surface of No. 3. The surface energy is increased in the portion where the bond of the atom is broken, and this portion appears everywhere to promote nucleation, so that the number of nucleation sites is significantly increased.

On the other hand, the rate of surface diffusion of copper atoms generated by decomposition of the raw material is almost the same as that in the normal case without the hydrogen beam 29, so that the size of the granular deposit shown in FIG. Density increases. As a result, the flatness of the deposited layer is enhanced, and film formation with severe surface irregularities can be avoided. As shown in FIG. 5 (a), when forming a thin film layer inside the dent, copper deposition is performed while tilting the irradiation direction of the hydrogen beam, and the nucleation density at the bottom and the side wall of the dent is made uniform so as to be uniform. It is possible to form a continuous copper thin film of the same quality.

Further, as shown in FIG. 5B, the substrate Wf
Irradiating the hydrogen beam 29 in a direction perpendicular to the bottom surface of the dent provided on the surface and parallel to the side wall, the irradiation energy density for the former becomes significantly larger than that for the latter. -Dissociation occurs substantially only on the bottom surface. Thus, the growth direction of copper deposition is limited to only one direction from the bottom to the entrance. As a result, blockage due to overhang of the deposited copper at the entrance can be avoided, and the occurrence of the cavity defect 16 shown in FIG. 3B can be avoided.

Further, in the method of the present invention, the film is formed in a region where the normal operating pressure is approximately 1 × 10 ⁻⁴ Torr or less, which is extremely lower than that of the normal CVD. Film deposition can be performed in a larger so-called molecular flow region. Because it is a molecular flow space, the conventional CV
Unlike the granular flow space where D is performed, since there is no gas stagnation layer near the surface of the substrate Wf, deposition can be performed irrespective of the macroscopic gas flow velocity. In other words, a relatively high-speed deposition can be performed by reducing the flow rate of the source gas, and the source consumption efficiency can be improved. In addition, since hydrogen dissociation hardly occurs in ordinary thermal CVD, only the reaction of the formula (1) occurs (only half of the Cu contained in the raw material is used), but according to the method of the present invention, hydrogen ions H ^{Since the} active hydrogen such as ⁺ and hydrogen radical H ^* is abundantly present, the reaction of the formula (2) is also likely to occur, and Cu which is wasted as exhaust gas in ordinary CVD is used.
Can also be effectively applied to deposition and deposition. Also from this aspect, the deposition rate is high (doubling theoretically), and the utilization rate of the raw material is increased.

Further, by irradiating the hydrogen beam 29 of 200 eV to 10 keV, not only sputtering on the surface of the substrate Wf but also mixing at the atomic level of the interface between the deposited copper layer and the substrate Wf due to the penetration of hydrogen into the inside occurs. (See FIG. 6), so that the adhesion / bonding property between the deposited copper layer and the substrate Wf is greatly improved. In the above example, a hydrogen beam is used as the particle beam. However, it goes without saying that a chemical species other than the hydrogen beam can be used.

As a concept derived from the above-mentioned method, it is also effective to irradiate a hydrogen beam in advance before supplying the copper raw material gas. This is because, prior to Cu deposition, some of the atomic bonds on the surface of the TaN layer, which is the diffusion suppression layer of the base, are cut or reduced, or hydrogen is attached to or penetrated into the surface, thereby generating nuclei on the base side. By increasing points.

In the above example, copper (Cu) is deposited on the surface of the base material. However, the deposited material is not limited to copper, but may be other metals.

[0036]

As described above, according to the invention described in each claim, the following excellent effects can be obtained.

According to the first to fourth aspects of the present invention, the density of deposited nuclei on the surface of the substrate is increased by irradiating the substrate with a particle beam in parallel with and / or before the supply of the source gas. Is drastically increased, so that the surface morphology of the deposit layer deposited on the substrate surface tends to be flat. In addition, by changing the irradiation intensity of the particle beam depending on the location of the base material, the preferential growth direction of the deposited layer can be specified. Irradiation causes mixing at the atomic level at the interface between the deposited layer and the substrate surface, thereby greatly improving the adhesion between the deposited layer and the substrate.

According to the fifth aspect of the present invention, an ion source, an ion accelerating mechanism and a raw material supply mechanism are provided, and the raw material is supplied to the base material in parallel with the ordinary chemical vapor deposition process and / or before the supply of the raw material gas. Particle beam irradiation can be performed, so that the surface morphology of the deposit layer deposited on the substrate surface tends to be flat as described above, and by specifying the preferential growth direction of the deposited layer, And a coating / filling apparatus capable of preventing the occurrence of cavity defects by avoiding clogging and significantly improving the adhesion between the deposited layer and the substrate.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a conventional coating and filling apparatus by CVD.

FIGS. 2A and 2B are diagrams schematically showing a state of coating and filling inside a recess, wherein FIG. 2A shows a case of coating and FIG. 2B shows a state of filling.

FIG. 3 is a diagram schematically showing a typical example of a defect that frequently occurs with a copper coating and filling step by CVD.
FIG. 3A shows a case of coating, and FIG. 3B shows a case of filling.

FIG. 4 is a view showing a schematic configuration example of a coating / filling apparatus by CVD according to the present invention.

FIG. 5 is a view showing a state in which a copper film is deposited and deposited inside a recess by the coating and filling apparatus according to the present invention. FIG. 5 (a) shows a case where a hydrogen beam is tilted and irradiated, and FIG. It is a figure which shows the case where a hydrogen beam is irradiated vertically.

FIG. 6 is a diagram showing the energy of particles and the depth of penetration of a particle beam into a surface to be irradiated.

[Explanation of symbols]

21 reaction chamber 22 a susceptor 23 source container 24 H ₂ storage container 25 flow controller 26 vaporizer 27 source gas 28 fast ions generating mechanism 29 hydrogen beam 30 flow controller 31 heating and cooling mechanism 32 exhaust port 33 Cu (hfac) (tmvs )

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Araki 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (72) Inventor Hiroshi Nagasaka 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture Inside Ebara Research Institute, Limited (72) Inventor Momoko Kadoya 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa F-term in Ebara Research Institute, Limited 4K030 AA11 BA01 CA04 CA11 CA12 DA02 HA04 LA15 4M104 BB04 DD21 DD44 DD45 HH09 HH12 HH13 5F033 HH11 MM01 PP02 PP11 XX02 XX14

Claims (5)

[Claims] 1. A method of coating / filling a base material for coating / filling the inside of a fine recess provided on the surface of a base material by a chemical vapor deposition method, the method comprising: A method for coating / filling a substrate, comprising irradiating the substrate with a beam to coat / fill the inside of a fine recess provided on the surface of the substrate. 2. The method of coating and filling a substrate according to claim 1, wherein the irradiation of the substrate with a particle beam is performed by an electron beam or a charged particle beam, or an atomic beam or a molecular beam. And a method for coating and filling a substrate using at least one means. 3. The method for coating and filling a substrate according to claim 1, wherein the substrate is a silicon substrate for manufacturing a semiconductor device, and the recess formed on the surface of the substrate is for forming a semiconductor device wiring. Wherein the raw material gas is an organic complex gas containing copper. 4. The method for coating and filling a substrate according to claim 1 or 2, wherein irradiation of an ion beam, an atomic beam, or a molecular beam, which is one form of the particle beam, is performed as particles of the beam. A method for coating and filling a substrate, wherein the energy of the substrate is 200 eV or more and 10 keV or less. 5. An ion source required to generate at least a particle beam, an ion acceleration mechanism, and a raw material supply mechanism including an element of a material for coating and filling the inside of the recess formed on the surface of the base material are provided. An apparatus for coating / filling a substrate, having a function of irradiating the substrate with a particle beam in parallel with the execution of the chemical vapor deposition step and / or before the supply of the source gas.