JP2001240967A - Method and apparatus for covering and embedding micro recess on base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for covering and embedding micro recesses on a base material in which the configuration and the control are simple, the film deposition speed is high, and expensive raw materials such as organic complexes Cu(hfac), (tmvs) can be effectively utilized. SOLUTION: In the apparatus for covering and embedding micro recesses on the base material in which a main reaction chamber 31 is provided, the base material 33 is placed in the main reaction chamber 31, the raw gas of a conductive material is introduced in the main reaction chamber from a vaporizing apparatus 37, and small recesses on the surface of the base material 33 by the chemical vapor phase deposition method are covered or embedded by the conductive material, a hydrogen activating device 35 to feed hydrogen species (atom, atomic group, molecule) having the energy higher than that of the ground state is provided outside the main reaction chamber 31, the raw gas is introduced into the main reaction chamber 31 from a vaporizing device 7, and the hydrogen species having the energy higher than that of the ground state are introduced from the hydrogen activating device 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine wiring recess formed on the surface of a base material such as a semiconductor substrate (wafer).
u) and other conductive materials by chemical vapor deposition (hereinafter referred to as “CVD”).
Abbreviated as ") or embedded in the substrate surface
The present invention relates to an embedding method and apparatus.

[0002]

2. Description of the Related Art Reduction in line width and line spacing due to miniaturization of wiring accompanying high integration of semiconductor devices causes
It is urgently necessary to solve two problems, namely, a delay in signal transmission and an increase in the frequency of electromigration (EM) of wiring materials caused by an increase in current density (about 1 MA / cm ² or more) required for high-speed operation. It has become. With this in mind, it is inevitable to change at least the current aluminum-based wiring material.

FIG. 1 shows the physical properties of aluminum (Al) and other alternative wiring candidate materials. Currently, copper (Cu) has attracted the most attention among the materials shown in FIG. 1 because of its low electrical resistivity (1.7 μΩcm and 60% of that of aluminum).
%), And high electromigration (EM) resistance (the limiting current density is 4 to 10 times that of aluminum-based).

On the other hand, as shown in FIG. 1, unlike aluminum, copper has a drawback that etching (RIE) is extremely difficult. As a result, it becomes impossible to use the conventional lithography-etching method using aluminum for forming the wiring. Therefore, it is inevitable to adopt a so-called damascene method of embedding a wiring material in a fine recess provided in advance in an insulating layer on the surface of the base material.

[0005] In FIG. 2, copper is coated in fine depressions or
Representative specific means for embedding are summarized below. FIG.
As is clear from the above, the three methods, namely, CVD, sputter reflow, and electrolytic plating, in which a dent having a width of about 0.15 μm or less can be buried without any problem can be limited to CVD. It can be said that the nature is the highest.

However, as shown in FIG. 2, the disadvantages of embedding copper wiring by CVD are that the film formation (deposition) speed is slow and the film quality (both conductivity and EM resistance) is relatively poor.
It can be pointed out that the cost of raw materials increases.

[0007] In order to solve any of the above problems (1) and (2), a method of adding hydrogen gas or hydrogen radicals to an organic metal material and supplying it to a reaction chamber is usually proposed in CVD as shown in FIG. Have been.

FIG. 3 is a diagram showing a schematic configuration of a conventional hydrogen supply Cu-CVD apparatus. As shown in the figure, this hydrogen supply Cu-CVD apparatus is configured to include a vaporizer 1, a raw material container 2, a hydrogen container 3, and a main reaction chamber 4. An organic metal raw material is supplied from the raw material container 2 to the vaporizer 1, and a hydrogen (H ₂ ) gas is supplied from the hydrogen container 3, vaporized, evacuated and depressurized by a vacuum system, and heated to a predetermined temperature by the heater 6. The copper is deposited on the surface of the base material 5 placed in the main reaction chamber 4 and caused to react therein, thereby forming a copper thin film.

However, in the hydrogen supply Cu-CVD apparatus having the structure shown in FIG. 3, the effect of hydrogen addition is not always sufficient. This is because in order for hydrogen to react with other substances, hydrogen molecules need to be dissociated into hydrogen atoms, but it is very difficult to cause this dissociation only by applying heat from the heater 6, This is because the reaction between hydrogen and the source gas is incomplete.

The mechanism currently proposed as a mechanism for increasing the film forming rate by supplying hydrogen in CVD is shown below [Shoji Shiratani, Masao Watanabe, Applied Physics, 68, 3 (199)
9) P.I. 299-].

As a copper raw material, an organic complex Cu (hfac)
(Tmvs); hexafluoroacetylacetonate.
The following reactions (1) to (6) have been proposed as reactions occurring in a reaction chamber when using trimethylvinylsilane copper [Won-junLell et al, Ma.
t. Res. Soc. Symp. Proc. , J. et al.
A. T. Norman et al, Proceedi
ngs of the8 ^th Internationa
l IEEE VLSI Interconnectivity
on Conference (1991, New Y
ork) P. 123, G. S. Girolami,
et al, J.A. Am. Chem-Soc. , 115
(1993) P.A. 1015]

Total 2Cu ⁺¹ (hfac) (tmvs) (g) → Cu ⁰ (s) + Cu ⁺² (hfac) ₂ (g) + 2tmvs (g) (1)

Elemental correspondence 2Cu ⁺¹ (hfac) (tmvs) (g) → 2Cu ⁺¹ (hfac) (tmvs) (s) (2)

2Cu ⁺¹ (hfac) (tmvs) (s) → 2Cu ⁺¹ (hfac) (s) + 2tmvs (s) (3)

2tmvs (s) → 2tmvs (g) (4)

2Cu ⁺¹ (hfac) (s) → Cu ⁰ (s) + Cu ⁺² (hfac) ₂ (s) (5)

Cu ⁺² (hfac) ₂ (s) → Cu ⁺² (hfac) ₂ (g) (6)

As is apparent from the equation (1), Cu (hf
Since ac) (tmvs) causes a disproportionation reaction and decomposes, only half of the Cu originally contained in the raw material can be used, so that even if it is expensive, the loss of the expensive raw material is large. Here, by causing the reaction represented by the following equation (7), the Cu deposition rate is theoretically doubled, and there is a possibility that the raw material utilization rate can be improved.

Cu (hfac) + H → Cu + H (hfac) (7)

Although the increase in the deposition rate according to the equation (7) is actually observed, the deposition rate when H ₂ is used as the source carrier gas is 1. compared with that when Ar is used as the carrier gas. There is a report that it has increased only five-fold [Kuriya, Monthly Semiconductor]
World (1997.12) P. 176].

As shown in FIG. 4, when Cu was deposited while introducing hydrogen into the CVD apparatus and generating radical hydrogen by plasma, impurities in the film and electric resistivity were reduced, and the crystal grain size was reduced. [Ed., Shinzo Miyahara et al., Latest development of Cu wiring technology (1998.5 Realize), p. 74].

Radical hydrogen supply Cu-CVD shown in FIG.
The apparatus comprises a main reaction chamber 14 in which electrodes 15, 16 are arranged.
The electrode 15 is connected to an AC power source 18.
A high frequency AC voltage of 28 MHz is applied to the electrode 16 while a high frequency AC voltage of 28 MHz is applied to the electrode 16. Further, a substrate mounting table 19 is arranged in the main reaction chamber 14 so that the substrate 20 can be mounted.

The organometallic raw material is supplied to the vaporizer 11 from the raw material supply device 12, and hydrogen (H ₂ ) gas is supplied from the hydrogen container 13 to be vaporized. Supplying. In addition, hydrogen (H ₂ ) gas is supplied from the hydrogen container 13 to the portion of the main reaction chamber 14 where the electrode 16 is disposed, to generate hydrogen radicals by discharge. The generated hydrogen radicals are transferred to the electrode 15 and the substrate 20.
The copper flows into the main discharge portion generated during the process and deposits copper on the surface of the substrate 20 placed on the substrate placing table 19 to form a copper thin film.

However, the radical hydrogen supply Cu-CVD apparatus having the structure shown in FIG. 4 performs the Cu deposition and the hydrogen radicalization simultaneously in the same reaction chamber by applying different plasmas. However, there is a problem that it becomes complicated.

Further published literature (Aoki, et al,.
J. Electrochem. Soc. , Vol. 4
2, No. 1 (1995. 1) P.I. 166)
As shown in FIG. 5, a 100-500 W RF plasma generation chamber 21 (13.56 MHz, inductive coupling type) is used to generate hydrogen radicals, which are sent to the main reaction chamber 4 for copper deposition to perform a high quality film. There is a report that I got. In FIG. 5, reference numeral 5 denotes a substrate, and reference numeral 6 denotes a heater.

In the method shown in FIG. 5, RF discharge (13.56 MHz) is used to generate active hydrogen. on the other hand,
The size of the plasma space required for plasma generation is determined by the size of the trapping effect of electrons in the plasma.
A certain space size corresponding to the frequency of 13.56 MHz is required. Thus, for example, typically a frequency of 2.4
As compared with the case of microwave discharge using 5 GHz, there is a disadvantage that the plasma generation chamber 21 becomes relatively large.

[0027]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and solves the above-mentioned problems. By a simple structure and control, the film deposition rate is high, and for example, an organic complex Cu (hfac) It is an object of the present invention to provide a method and an apparatus for coating and embedding fine dents on a substrate surface, which can effectively use expensive raw materials such as (tmvs).

[0028]

According to a first aspect of the present invention, a substrate is placed in a reaction chamber, and a raw material gas of a conductive material is introduced into the reaction chamber. A method for coating or embedding a fine dent provided on the surface of a base material by a vapor deposition method with a conductive material, or a method for coating and embedding a fine dent on a base material surface, in which a raw material gas is introduced into a reaction chamber and separately introduced into the reaction chamber. It is characterized by introducing a hydrogen species (atom, atomic group, molecule, or the like) having higher energy than the ground state.

As described above, since hydrogen species (atoms, atomic groups, molecules, etc.) having higher energy than the ground state are separately introduced into the reaction chamber, dissociation of hydrogen molecules (H ₂ → H + H)
Various dissociation energies can be used, and the dissociation of hydrogen molecules and the subsequent application of energy by radical hydrogen can be performed relatively easily, and the film deposition rate is high and the raw material can be effectively used.・ Provide an embedding method.

[0030] The invention described in claim 2 is the same as that in claim 1.
In the method for covering and embedding a fine dent in the base material surface described in the above, the base material is a semiconductor substrate, the fine dent provided in the base material is along a wiring pattern constituting a conductive path provided in the semiconductor substrate, The conductive material to be coated and filled is copper (C
u), silver (Ag), aluminum (Al) alone, or an alloy containing any of these as a main component.

By using a semiconductor substrate as a base material as described above, copper (Cu), silver (Ag), aluminum (Al) alone, Alternatively, a conductive material made of an alloy containing any one of these as a main component can be coated and embedded quickly and effectively using the raw material.

The third aspect of the present invention is the first aspect of the present invention.
Or in the method for coating and embedding a fine dent on a substrate surface according to item 2, wherein a certain energy is applied to the hydrogen molecule (H ₂ ) or a catalyst is generated in order to generate a hydrogen species having higher energy than the ground state. Is characterized by utilizing the action of

As described above, certain kinds of energy (for example, electromagnetic waves, microwaves, ultraviolet rays, electric discharges (glow, arc, corona, silent, atmospheric discharge, etc.)) are generated in hydrogen molecules (H ₂ ).
) Or by contact with plasma, flame, or high-temperature metal (filament), a hydrogen species having higher energy than the ground state can be easily generated. In addition, by utilizing the function of the catalyst, activation can be performed with lower energy than normal activation energy.

The invention described in claim 4 is the same as the claim 2
Or the method of coating / embedding the fine dents on the base material surface according to 3 above, wherein the raw material as the copper (Cu) supply source is hexafluoroacetylacetonate / trimethylvinylsilane copper, and the fine dents of the base material are covered or embedded. The surface temperature of the substrate when the heat treatment is performed is set in the range of 141 to 175 ° C., and copper (Cu) or a copper alloy is used as a conductive material to be coated and filled.

As described above, Cu (hfa
c) When performing thermal CVD using (tmvs), the reaction on the substrate surface can control the film forming rate (surface reaction rate-limiting) in the range of the substrate temperature of 141 to 175 ° C. By setting the surface temperature in the range of 141 to 175 ° C., macroscopically uniform film deposition can be realized over the entire surface of the substrate.

According to a fifth aspect of the present invention, a reaction chamber is provided, a substrate is placed in the reaction chamber, and a source gas of a conductive material is introduced into the reaction chamber from a source gas supply mechanism.
A device for coating or embedding fine dents provided on the surface of a substrate with a conductive material by chemical vapor deposition and having a higher energy than the ground state outside the reaction chamber. A hydrogen species supply mechanism that supplies hydrogen species (atoms, atomic groups, molecules, etc.) is provided. The source gas is introduced from the source gas supply mechanism into the reaction chamber, and the hydrogen species supply mechanism has higher energy than the ground state. It is characterized in that it is configured so that hydrogen species can be introduced.

As described above, hydrogen species (atoms, atomic groups, molecules, etc.) having higher energy than the ground state outside the reaction chamber
Since a hydrogen species supply mechanism that supplies hydrogen can be applied, various dissociation energies can be applied to dissociate hydrogen molecules, so it is relatively easy to dissociate hydrogen molecules and subsequently apply energy by radical hydrogen Becomes In addition, since the operation of the reaction chamber and the hydrogen species supply mechanism can be performed under completely independent conditions and the respective reactions can be sufficiently controlled, precise adjustment of the composition and structure of the deposited film can be easily performed. it can.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, a case where the substrate surface minute dent coating / embedding device is constituted by a Cu-CVD device will be described. FIG. 6 is a diagram showing a schematic configuration of a Cu-CVD apparatus according to the present invention. In FIG. 5, reference numeral 31 denotes a main reaction chamber, in which a substrate mounting table (susceptor) 32 for mounting a substrate 33 is disposed. The main reaction chamber 31 is connected to a vacuum exhaust system such as a vacuum pump (not shown). The substrate mounting table 32 can heat the substrate mounting surface with a built-in heater 34.

Reference numeral 35 denotes a hydrogen activating device for activating hydrogen (H ₂ ) gas supplied from the hydrogen storage 36, and the activated hydrogen gas is supplied into the main reaction chamber 31. 37
Is a vaporizer for vaporizing the raw material supplied from the raw material supply device 38, and the vaporized raw material gas is supplied into the main reaction chamber 31.

As shown in FIG. 6, the hydrogen activating device 35
Is a separate element from the main reaction chamber 31 and has a structure in which the hydrogen gas supplied from the hydrogen storage 36 is activated to have a higher energy form than the ground state, and is sent to the main reaction chamber 31. I have.

In the hydrogen activating device 35, in order to increase the energy of hydrogen, a light beam including an electromagnetic wave, a microwave, an ultraviolet ray, a laser beam, an electron beam, a radiation, a high-temperature object, and a discharge (glow, arc) , Corona, silent, atmospheric pressure discharge or the like), plasma, flame or the like. In addition, the hydrogen activation device 35 may be configured to be able to activate with lower energy than normal activation energy by utilizing the function of a catalyst.

Here, the category of hydrogen having high energy includes a hydrogen species having higher energy than the ground state such as active hydrogen, hydrogen atom, excited hydrogen atom, ionized hydrogen, hydrogen ion, etc. , Atomic groups, molecules, etc.).

Originally, in order for hydrogen to react with another substance, the dissociation of the following formula (8) is required. However, it is very difficult to cause dissociation by mere heat because of strong bonding of hydrogen molecules. Have been.

H ₂ → H + H (8)

Therefore, the hydrogen supply C having the configuration shown in FIG.
It is very difficult for a u-CVD apparatus to cause a reaction.

On the other hand, the Cu according to the present invention having the structure shown in FIG.
In a CVD apparatus, various dissociation energies other than heat can be applied, so that the dissociation of hydrogen molecules and the subsequent energization by radical hydrogen can be performed relatively easily.

Further, in the Cu-CVD apparatus shown in FIG.
Since the main reaction chamber 31 and the hydrogen activating device 35 are configured separately, it is possible to apply energy to hydrogen to increase the degree of the activity under sufficiently controlled conditions. Therefore, the radical hydrogen supply C having the configuration shown in FIG.
As in the case of a u-CVD apparatus, it is possible to avoid complication caused by generating plasmas having different frequencies in the same system.

That is, by using the Cu-CVD apparatus according to the present invention, the main reaction chamber 31 and the hydrogen
Step 5 is performed under completely independent conditions and the reaction can be sufficiently controlled, so that the composition and structure of the film to be deposited can be precisely adjusted, and it is easy to cope with mass production applications where reproducibility is important. There is an advantage.

By the mechanism described above, the equation (8) is efficiently used.
Can be caused, and various inconveniences associated with the conventional method can be eliminated. Therefore, radical species such as active hydrogen atoms can be easily generated and introduced into the main reaction chamber 31. As a result, the reduction reaction according to the formula (7) is surely caused to increase the deposition rate and improve the consumption efficiency of the copper raw material, and the composition (including the impurity amount) of the deposited copper as described in the above section “0021”. ), Physical properties (such as electrical resistivity), and metal structure (including crystal grain size) can be improved.

Further, Cu (hfac) (tm
vs.), when the thermal CVD is performed, the substrate temperature is 1
In the temperature range of 41 to 175 ° C., it is considered that the reaction on the substrate surface can control the film forming rate (surface reaction rate-determining) [G. S. Girolami, et al,
J. Am. Chem-Soc. , 115. (1993)
P. 195].

Since the flow state of the raw material gas inevitably fluctuates from place to place, in order to realize macroscopically uniform film deposition over the entire surface of the substrate 33, a surface reaction rate-control region independent of the flow rate of the raw material gas is required. It is necessary to perform CVD film formation. Therefore, the surface temperature of the side of the substrate 33 on which the dents for covering or embedding Cu are formed is controlled to be in the range of 141 to 175 ° C.

In the above example, copper (Cu) is used as a conductive material for covering or embedding a fine dent formed on the surface of the base material 33. However, copper (Cu) is used as a conductive material. ), But may be copper (Cu), silver (Ag), aluminum (Al) alone, or an alloy containing any of these as a main component.

[0053]

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

According to the first aspect of the present invention, hydrogen species (atoms, atomic groups, molecules, etc.) having higher energy than the ground state are introduced into the reaction chamber separately from the supply of the raw material gas. Various dissociation energies can be used for the dissociation (H ₂ → H + H) of hydrogen, and the dissociation of hydrogen molecules and the subsequent energization by radical hydrogen can be performed relatively easily, the film deposition rate is high, and the raw material is effectively used. It is possible to provide a method of coating and embedding a fine dent on a substrate surface that can be used.

According to the second aspect of the present invention, since the base material is a semiconductor substrate, copper (Cu) and silver (Ag) are formed in fine recesses for forming a wiring pattern provided on the surface of the semiconductor substrate. , Aluminum (Al), or a conductive material made of an alloy containing any one of them as a main component can be coated or buried quickly and effectively by using raw materials.

According to the third aspect of the present invention, the hydrogen molecules (H ₂ ) have a certain energy [for example, electromagnetic waves, microwaves, ultraviolet rays, electric discharges (glow, arc, corona, silent, atmospheric discharge, etc.). )) Or
By contact with plasma, fire, and high-temperature metal (filament), hydrogen species having higher energy than the ground state can be easily generated. In addition, by utilizing the function of the catalyst, activation can be performed with lower energy than normal activation energy.

According to the fourth aspect of the invention, when thermal CVD is performed using Cu (hfac) (tmvs) as a raw material, a reaction on the surface of the substrate is performed at a substrate temperature of 141 to 175 ° C. Can control the film forming speed (surface reaction rate-determining), so that macroscopically uniform film deposition can be realized over the entire surface of the base material by setting the surface temperature within the range of 141 to 175 ° C. Can be.

According to the fifth aspect of the present invention, a hydrogen species supply mechanism for supplying a hydrogen species (atoms, atomic groups, molecules, etc.) having higher energy than the ground state outside the reaction chamber is provided. Since various dissociation energies can be applied to dissociate hydrogen molecules, a micro-dent coating / embedding device that can dissociate hydrogen molecules and subsequently apply energy by radical hydrogen can be used relatively easily. Can be provided. In addition, since the operation of the reaction chamber and the hydrogen species supply mechanism can be performed under completely independent conditions and the reaction can be sufficiently controlled, the fine adjustment of the composition and structure of the deposited film can be easily performed. A dent covering / embedding device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing the physical properties of aluminum (Al) and other alternative wiring candidate materials.

FIG. 2 is a diagram collectively showing typical specific means for coating or embedding copper in fine recesses.

FIG. 3 is a diagram showing a schematic configuration of a conventional hydrogen supply Cu-CVD apparatus.

FIG. 4 is a diagram showing a schematic configuration of a conventional radical hydrogen supply Cu-CVD apparatus.

FIG. 5 is a diagram showing a schematic configuration of a conventional radical hydrogen supply Cu-CVD apparatus.

FIG. 6 is a view showing a schematic configuration of a Cu-CVD apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 31 Main reaction chamber 32 Substrate mounting table (susceptor) 33 Substrate 34 Heater 35 Hydrogen activation device 36 Hydrogen storage 37 Vaporization device 38 Raw material supply device

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yuji Araki 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 4K030 AA06 AA11 AA17 BA01 BA02 CA04 CA12 FA01 FA02 FA07 FA08 FA10 FA14 FA15 JA10 LA15 4M104 BB02 BB04 BB08 DD44 DD45 5F033 HH09 HH11 HH14 MM01 PP02 PP06 PP11 WW03 XX00

Claims (5)

[Claims] 1. A substrate is placed in a reaction chamber, a raw material gas of a conductive material is introduced into the reaction chamber, and a fine recess provided on the surface of the substrate by a chemical vapor deposition method is covered with the conductive material. Or a method of coating and embedding a fine dent in a substrate surface to be embedded, wherein the raw material gas is introduced into the reaction chamber, and a hydrogen species (atom, atomic group) having higher energy than the ground state is separately introduced into the reaction chamber. , Molecules, etc.). 2. The method according to claim 1, wherein the fine dent is coated on the substrate surface.
In the embedding method, the base material is a semiconductor substrate, the fine recess provided in the base material is along a wiring pattern constituting a conductive path provided in the semiconductor substrate, and the conductive material covering and filling the recess is A method of coating and embedding fine dents on a substrate surface, comprising copper (Cu), silver (Ag), aluminum (Al) alone, or an alloy containing any of these as a main component. 3. The method according to claim 1, wherein the hydrogen molecule (H ₂ ) is used for generating a hydrogen species having higher energy than the ground state. A method for coating and embedding fine dents on a substrate surface, which comprises applying seed energy or utilizing the action of a catalyst. 4. The method according to claim 2, wherein the raw material as a copper (Cu) supply source is copper hexafluoroacetylacetonate / trimethylvinylsilane copper. The method is characterized in that the surface temperature of the substrate at the time of coating or embedding of fine dents is in the range of 141 to 175 ° C., and that copper (Cu) or a copper alloy is used as a conductive material to be coated and filled. Coating / embedding method for fine dents on the substrate surface. 5. A reaction chamber is provided, a base material is placed in the reaction chamber, and a raw material gas of a conductive material is introduced into the reaction chamber from a raw material gas supply mechanism, and the base material is formed by a chemical vapor deposition method. A substrate surface fine dent coating / embedding device for covering or embedding a minute dent provided on the surface of the substrate with a conductive material, wherein a hydrogen species (atom, atomic group) having a higher energy than the ground state outside the reaction chamber. , Molecules, etc.), a source gas is introduced from the source gas supply mechanism into the reaction chamber, and a hydrogen species having higher energy than the ground state is introduced from the hydrogen species supply mechanism. The substrate surface has a fine dent coating
Implanting device.