JPH05195210A - Integrated circuit, its production and thin film forming method therefor - Google Patents

Abstract

PURPOSE:To produce the integrated circuit which is constituted by forming wiring layers via a barrier layer on a substrate and forming the barrier layer of a Ti-Ni compd. which is gradually increased in a Ti content and N content from the lower part to the upper part and has an excellent electrical contact property and barrier property. CONSTITUTION:A gaseous mixture contg. gaseous N2 or gaseous mixture contg. a nitrogen element is introduced near an Si substrate 62 in a vacuum chamber while the introduction rate thereof is successively regulated at the time of producing the integrated circuit. While the Si substrate 62 is kept irradiated with inert gaseous ions, the surface of the Si substrate 62 is irradiated with the ions by a cluster type ion source, by which the Ti layer 45 is formed thereon. Further, TiNx layers 68, 67 in which the N content (X) increases gradually are formed thereon by regulating the supply rate of the N-contg. gas. The barrier layer 61 is formed of the Ti layer 65 and the TiNx layers 68, 67 varying in the value X. The wiring layer 60 is formed thereon. The integrated circuit formed with the high-quality barrier layer 61 having the excellent electrical contact property and barrier property is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, a method for manufacturing the same, and a thin film forming apparatus for the same.

[0002]

2. Description of the Related Art Conventionally, at the boundary between a wiring layer of an LSI (Large Scale Integrated Circuit) and a silicon substrate, the wiring material of the wiring layer is prevented from diffusing into the silicon substrate and the wiring material and the silicon substrate are A material such as titanium nitride is used as a barrier layer or an adhesion layer in order to secure the electrical contact of. As the miniaturization of LSI progresses, the design rule reaches half micron, and a method capable of depositing a barrier layer capable of ensuring good contact is required.

FIG. 7 shows a wiring portion contact hole of a 64M DRAM having a simple stack type cell structure and its structure, which are published in the proceedings of SEMICON Japan, 60 is an aluminum / silicon / copper alloy wiring layer, and 61 is nitrided. A titanium barrier layer, 62 is a silicon substrate, 63 is a contact hole, 64 is a through hole, and 69 is an insulating layer. The barrier layer 61 of the above integrated circuit is coated on the silicon substrate 6 by a method such as a sputtering method or a CVD method.

[0004]

In the conventional barrier layer made of titanium nitride of an integrated circuit, when the design rule becomes smaller and the film thickness is further reduced, the variation of the characteristics in the plane becomes remarkable, and the wiring layer. There is a problem in that the interaction and diffusion action between 60 and the silicon substrate 62 cannot be suppressed. The present invention has been made to solve the above problems, and obtains an integrated circuit having a high-quality barrier layer having good electrical contact properties and good barrier properties, a method of manufacturing the same, and a thin film forming apparatus thereof. The purpose is to

[0005]

The barrier layer of the integrated circuit according to claim 1 of the present invention is composed of a titanium nitride (TiNx) thin film layer in which the composition X changes from the substrate toward the wiring layer. ..

The barrier layer of the integrated circuit according to the second aspect of the present invention is formed of a titanium layer, a dititanium nitride layer, and a titanium nitride layer in this order from the substrate toward the wiring layer.

The barrier layer of the integrated circuit according to claim 3 of the present invention comprises a titanium (Ti) layer from the substrate toward the wiring layer,
The titanium nitride (TiNx) layer is formed so that the nitrogen component gradually increases with respect to the titanium composition, and finally the titanium nitride (TiN) layer is formed in this order.

According to a fourth aspect of the present invention, in a method for manufacturing an integrated circuit, the amount of nitrogen gas introduced into the vicinity of the substrate in the vacuum chamber is sequentially controlled so that the cluster type ion source irradiates the substrate with ions. Titanium is vapor-deposited to form the barrier layer composed of a titanium nitride (TiNx) thin film layer in which the composition X changes.

According to a fifth aspect of the present invention, in the method of manufacturing an integrated circuit, the amount of the mixed gas of nitrogen gas or the mixed gas containing nitrogen element introduced in the vicinity of the substrate in the vacuum chamber is sequentially controlled so that the substrate is formed. Titanium is vapor-deposited while irradiating ions on the substrate by a cluster type ion source while irradiating inert gas ions to form the barrier layer composed of a titanium nitride (TiNx) thin film layer in which the composition X changes. is there.

A thin film forming apparatus for an integrated circuit according to a sixth aspect of the present invention is provided with a cluster type ion source having a gas introducing pipe for introducing nitrogen gas having a regulated flow rate in the vicinity of the substrate.

According to a seventh aspect of the present invention, there is provided a thin film forming apparatus for an integrated circuit, wherein a cluster type ion source having a gas introduction tube for introducing a nitrogen gas, the flow rate of which is adjusted, and a gas for ionizing an inert gas. The gas ion source includes an ionization unit and an acceleration unit that accelerates and controls the inert gas ions.

[0012]

In the integrated circuit of the first to fifth aspects of the present invention, even if the barrier layer is thinned, it has good electrical contact and barrier properties.

The thin film forming apparatus for an integrated circuit according to claims 6 and 7 of the present invention provides an apparatus for forming a barrier layer having good electrical contact and barrier properties. Further, in the thin film forming apparatus for an integrated circuit according to claim 7, the nitrogen gas introduced in the vicinity of the substrate is activated and deposited on the substrate while being irradiated with the inert gas ions, so that the reaction efficiency with vapor or clusters is improved. To do.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional structure of an LSI contact hole and a through hole according to one embodiment of the present invention.
Reference numeral 0 is a wiring layer, 61 is a barrier layer having a three-layer structure of a titanium layer 65 having a compositionally gradient function, a dititanium nitride layer 68 and a titanium nitride layer 67, 62 is a silicon substrate, and 69 is an insulating layer.

FIG. 2 shows another embodiment of the barrier layer of the present invention, in which 60 is a wiring layer, 61 is a titanium layer 65 having a compositionally graded function, and the nitrogen composition is gradually larger than the titanium composition. Titanium Nitride (TiNx) Layer 6
6 and a barrier layer composed of a titanium nitride layer 67, and 62 is a silicon substrate.

FIG. 3 is a sectional view schematically showing a titanium nitride thin film manufacturing apparatus according to an embodiment of the present invention.
In the figure, 5 is a vacuum exhaust system for holding the vacuum chamber 6 at a predetermined vacuum degree, 4 is a reactive gas introduction system, for example, a gas cylinder 41 filled with nitrogen gas, for introducing the reactive gas into the vacuum chamber 6. The flow control valve 42 and the introduction pipe 43 for introducing the reactive gas. 1 is a steam source,
Sealed crucible 12 having nozzle 11, and this crucible 1
Filament 13 for heating 2 and heat shield plate 14
Consists of. 15 is titanium filled in the crucible 12,
16 is the vapor of titanium 15 which is this vapor deposition material
It is a cluster (lumpy atomic group) formed by being ejected from the second nozzle 11.

Reference numeral 2 denotes an ionization means for the cluster 16, which is an electron beam emitting filament 21 and this filament 21.
It is composed of an electron extraction electrode 22 and a heat shield plate 23 for extracting and accelerating electrons from. 3 is an accelerating electrode which is an accelerating means for accelerating the ionized cluster 16 with an electric field to give kinetic energy, 7 is a substrate on which a titanium nitride thin film is formed, 8 is a DC power supply 81, 82 for biasing , 83 and power supplies 84, 8 for heating filaments
5 is a power supply device that is housed.

First, the function of each bias power supply in the power supply device 8 is as follows. The first DC power supply 81 is arranged so that the thermoelectrons emitted from the crucible heating filament 13 heated by the filament heating power supply 84 collide with the crucible 12 so that the thermoelectrons collide with the crucible 12.
Bias the potential of the positive. Next, the second DC power supply 82 extracts the thermoelectrons emitted from the ionized filament 21 heated by the power supply 85 for heating the filament, and draws out the electrode 2
The electric potential of the extraction electrode 22 is positively biased with respect to the filament 21 so as to be drawn inside. Also,
The third DC power supply 83 positively biases the potentials of the electron beam extraction electrode 22 and the crucible 12 with respect to the acceleration electrode 3 which is the ground potential, and accelerates the positively charged cluster ions by the electric field lens formed therebetween. To do.

The next operation will be described. Vacuum exhaust system 5
After the inside of the vacuum chamber 6 is evacuated to a vacuum degree of 10 ⁻⁴ Torr or less, the flow rate adjusting valve 42 is opened and nitrogen gas is introduced through the gas introducing pipe 43. On the other hand, when the emitted electrons collide with the crucible 12 and are heated by the electric field applied by the DC power source 81 from the crucible heating filament 13 to a temperature at which the vapor pressure in the crucible 12 becomes several Torr, the vapor deposition material titanium 15 is heated. Evaporate and jet from the nozzle 11 into vacuum. When the vapor to be injected passes through the nozzle 11, the vapor is accelerated and cooled by adiabatic expansion and condensed to form a cluster of massive atoms called a cluster 16. The clusters 16 are then partially ionized by the electrons emitted from the ionizing filaments 21 to become cluster ions, which are further accelerated by the electric field formed by the acceleration electrode 3 and collide with the substrate 7 together with the non-ionized neutral clusters. To do. On the other hand, a reactive nitrogen gas exists near the substrate 7, and the reaction between the clusters 16 of titanium 15 and the reactive gas proceeds on the substrate 7 to deposit a titanium nitride thin film on the substrate 7.

FIG. 4 is an X-ray diffraction analysis of the crystallinity of the titanium nitride layer formed when the amount of nitrogen gas introduced was varied. The nitrogen partial pressure was 4.0 × 1.
Below 0 ^-6 Torr, titanium (Ti), 1.0x10 ^-5
At Torr, dititanium nitride (Ti ₂ N), 1.7 × 10 ⁻⁵
Torr uses dititanium nitride (Ti ₂ N) and titanium nitride (T
iN) and mixed crystal of 3.0 × 10 ⁻⁵ Torr or more is titanium nitride (TiN), and the crystallinity and the composition of nitrogen and titanium in the film can be freely controlled by the partial pressure of nitrogen. In addition, the value of PN ₂ in () in FIG.
Is the partial pressure of nitrogen in the vacuum chamber 6 before evaporating.

On the other hand, FIG. 5 shows the electrical resistivities of titanium nitride (TiNx) layers having various compositions. It can be seen that the electrical resistance is lower as the composition is low in nitrogen and in titanium.

On the other hand, FIG. 6 shows another embodiment of the manufacturing apparatus of the present invention. 40 is an introducing pipe for introducing nitrogen gas into the vicinity of the substrate 7, 41 is an argon cylinder, 42 is a gas flow rate adjusting valve, 43 is a gas introduction tube, 44 is a filament (cathode) which is an electron beam emitting means, 45 is an electron beam extraction electrode (anode) which forms plasma inside, 46
Is an accelerating means for accelerating the ions to irradiate the substrate 7 through the porous electrode 47, 48 is a filament heating power source for heating the filament 44 which is an electron beam emitting means, 49
Reference numeral 50 is a DC power source for biasing the electron beam extraction electrode 45 to a positive potential with respect to the filament 44 serving as an electron beam emitting means, and 50 is a DC power source for biasing the electron beam extraction electrode 45 to a positive potential with respect to the acceleration electrode 46. is there.

Further, in another embodiment of the present invention, 40 may be a gas introduction pipe for introducing a mixed gas of nitrogen gas or a mixed gas containing a nitrogen element in the vicinity of the substrate 7.

Next, the operation of this titanium nitride thin film forming apparatus will be described. By introducing nitrogen gas into the vicinity of the substrate 7 by the gas introduction pipe 40 into the vacuum chamber 6 kept in a high vacuum by the vacuum exhaust device 5, and by adjusting the flow rate adjusting valve 42 from the gas cylinder 41, the gas ion source Argon gas, which is an inert gas, is introduced into the electron beam extraction electrode 45 of the above through the gas introduction pipe 43, and the gas pressure in the vacuum layer 6 is adjusted to 10 ⁻⁵ to 10 by combining the argon partial pressure and the nitrogen partial pressure.
^-3 Adjust to about Torr. An electron beam extraction electrode 45 is supplied from a heated filament 44, which is an electron beam emitting means, by a filament heating power source 48.
DC power supply 49 so that the electron beam is emitted toward
When a bias voltage is applied by, the emitted thermoelectrons collide with the argon gas in the electron beam extraction electrode 45 to form plasma, and ionization is performed. The generated nitrogen ions are accelerated by the electric field formed by the acceleration electrode 46, extracted from the porous electrode 47, and irradiated on the substrate 7. Then, when the crucible 12 is heated by the crucible heating filament 13 to a temperature at which the vapor pressure in the crucible 12 becomes several Torr, titanium 15, which is a vapor deposition material, evaporates and is ejected from the nozzle 11. The injected titanium vapor or cluster 16 is partially ionized by the electrons emitted from the ionization filament 21 next, and the acceleration electrode 3
The substrate 7 is accelerated by the electric field formed in 1 and collides with the substrate 7 together with the non-ionized vapor or cluster.

On the other hand, the nitrogen gas supplied from the gas introducing pipe 40 exists in the substrate 7 and the vicinity of the substrate 7, and is in an active state where it is excited, dissociated or ionized by the irradiation of argon ions. The titanium vapor oxynitride collides with the titanium vapor or clusters and the reaction proceeds efficiently to deposit a titanium oxynitride thin film on the substrate 7. At this time, if the amount of nitrogen ions with which the substrate 7 is irradiated is changed, the composition ratio of titanium and nitrogen in the film changes, so that the composition ratio can be freely controlled.

[0026]

As described above, according to the integrated circuit of the first to third aspects of the present invention, the barrier layer has the graded structure in which the composition ratio of titanium and nitrogen is changed. Even if the barrier layer is thinned, the electrical contact and the barrier property are improved.

According to the integrated circuit manufacturing method of the fourth and fifth aspects of the present invention, the amount of nitrogen introduced into the vacuum chamber is controlled by the inclined structure for changing the composition ratio of titanium and nitrogen. This has the effect that it can be easily formed.

According to the thin film forming apparatus for an integrated circuit according to the sixth and seventh aspects of the present invention, it is possible to form a barrier layer having a graded structure in which the compositions of titanium and nitrogen are changed. Further, according to the thin film forming apparatus of the seventh aspect, the nitrogen gas introduced in the vicinity of the substrate is activated and vaporized while being irradiated with the inert gas ions, so that the reaction efficiency with vapor or clusters is improved. There is an effect that a high quality thin film is formed.

[Brief description of drawings]

FIG. 1 is a sectional view of a large scale integrated circuit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a large scale integrated circuit according to another embodiment of the present invention.

FIG. 3 is a sectional view of a thin film forming apparatus for an integrated circuit showing an embodiment of the present invention.

FIG. 4 is a diagram showing crystallinity of titanium nitride.

FIG. 5 is a diagram showing the electrical resistivity of titanium nitride.

FIG. 6 is a sectional view of an integrated circuit thin film forming apparatus showing another embodiment of the present invention.

FIG. 7 is a sectional view showing an example of a conventional large-scale integrated circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vapor generation source 2 Ionizing means 3 Accelerating electrode 6 Vacuum tank 7 Substrate 40 Gas introducing tube 43 Gas introducing tube 44 Filament (electron beam emitting means) 45 Electron beam extracting electrode 46 Accelerating means 60 Wiring layer 61 Barrier layer 62 Silicon substrate 65 Titanium Layer 66 Titanium nitride (TiNx) layer 67 Titanium nitride layer 68 Nititanium nitride layer

Claims (7)

[Claims] 1. In an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, the barrier layer comprises titanium nitride (T) whose composition X changes from the substrate toward the wiring layer.
iNx) An integrated circuit characterized by being a thin film layer. 2. In an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, the barrier layer is a titanium layer, a dititanium nitride layer and a titanium nitride layer in this order from the substrate toward the wiring layer. An integrated circuit characterized by being formed by. 3. In an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, the barrier layer is a titanium layer from the substrate toward the wiring layer, and a nitrogen composition is gradually added to a titanium composition. Titanium Nitride (T
An integrated circuit comprising an iNx) layer and finally a titanium nitride (TiN) layer. 4. In a method of manufacturing an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, the amount of nitrogen gas introduced in the vicinity of the substrate in a vacuum chamber is sequentially controlled, and a cluster type ion source is used. Titanium nitride (Ti) whose composition X changes by vapor-depositing titanium on the substrate while irradiating with ions.
Nx) A method of manufacturing an integrated circuit, wherein the barrier layer made of a thin film layer is formed. 5. A method for manufacturing an integrated circuit in which a wiring layer is formed on a substrate via a barrier layer, the amount of a mixed gas of nitrogen gas or a mixed gas containing a nitrogen element being introduced near the substrate in a vacuum chamber. It is composed of a titanium nitride (TiNx) thin film layer in which the composition X changes by sequentially controlling and depositing titanium while irradiating the substrate with ions by a cluster type ion source while irradiating the substrate with inert gas ions. A method of manufacturing an integrated circuit, wherein the barrier layer is formed. 6. A vacuum chamber in which a substrate is placed and which is maintained at a predetermined vacuum degree, a gas introduction pipe for introducing a nitrogen gas whose flow rate is adjusted to the vicinity of the substrate, and a vapor deposition material directed toward the substrate. Of the vapor deposition material to generate vapors or clusters of the vapor deposition material, ionization means for ionizing a part of the vapor or clusters of the vapor deposition material, and ionized vapor or cluster ions by acceleration control. A thin film forming apparatus for an integrated circuit, comprising a cluster-type ion source configured by an accelerating means for transporting the vapor or a cluster of a vapor deposition substance to the substrate. 7. A vacuum chamber in which a substrate is arranged and which is maintained at a predetermined degree of vacuum, and a gas introduction for introducing a mixed gas of nitrogen gas or a mixed gas containing a nitrogen element, the flow rate of which is adjusted near the substrate. A tube, a vapor source for ejecting vapor of a vapor deposition material toward the substrate to generate vapor or a cluster of the vapor deposition material, an ionization means for ionizing a part of the vapor or cluster of the vapor deposition material,
A cluster-type ion source configured by an acceleration means for accelerating and controlling the ionized vapor or cluster ions and transporting the vaporized ions or vapors of the non-ionized vapor deposition material to the substrate, and an inert gas provided in the vacuum layer. Gas ionization means for ionizing an inert gas, which comprises an introduction tube, an electron beam extraction electrode arranged at the introduction part of the inert gas and an electron beam emission means, and acceleration control of the inert gas ionized by the electron beam emission means A thin film forming apparatus for an integrated circuit, comprising: