JP2707951B2 - Sputtering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering method, and more particularly to a magnetron sputtering method with improved straightness of sputtered particles.

[0002]

2. Description of the Related Art Generally, in a process of manufacturing a semiconductor device, a metal film is deposited on a semiconductor substrate and processed into a required pattern to form an electrode and a wiring. In recent years, electrodes and wirings have been miniaturized with miniaturization of elements of semiconductor devices, and accordingly, high bottom coverage has been required for deposition of a metal film in a contact hole having a large aspect ratio. I have. For example, when contacting a semiconductor with a multi-layered metal film, if the bottom coverage is poor, the metal material for contacting is insufficient, and a good contact cannot be formed.

As a means for improving the bottom coverage of a deposited metal film, a sputtering method using a collimator is known. In this method, as shown in FIG. 1, a collimator 106 is provided between a target 103 and a semiconductor substrate 107 for selectively passing sputter particles traveling in a normal direction of the substrate, and a processing gas introduction unit 102 is provided. Ar gas is further introduced, plasma is generated by the magnetron 101, and sputter deposition is performed.

A sputtering method using a collimator as described above is known from Japanese Patent Application Laid-Open No. Hei 1-116070. A sputtering method using a processing gas other than Ar is disclosed in JP-A-63-29504 and JP-A-2-14.
No. 8417 is known. In the former, in a bias sputtering method for forming an Al film or the like, Ar gas is used as a processing gas.
The use of a heavier Kr gas, Xe gas, Rn gas, or the like is intended to prevent gas components from being taken into a silicon wafer. At the time of deposition by sputtering, Kr or Xe is used as a processing gas to improve the vertical anisotropic magnetic field Hk.

[0005]

In the above-mentioned conventional sputtering method using a collimator, as shown in FIG. 3B, since the direction of the sputtered particles emitted from the target is not anisotropic, There was a problem. The deposition rate of the generated sputter particles on the substrate was low, and a long time was required for film formation, and workability was poor. The amount of sputter particles deposited on the side wall of the collimator increases, and particles are easily generated, which causes a decrease in yield. The life of the target was short, and this increased costs, including the number of man-hours for replacement work.

[0006]

To solve the above problems [Means for Solving the Problems] According to the present invention, arranged targets on magnetron, the substrate of the workpiece disposed opposite the target, before
A normal direction of the substrate between the target and the substrate
Collimation that selectively passes sputtered particles that travel through
In sputtering method for performing sputter deposition by placing the data, magnetron sputtering method characterized by Ru with large gas specific gravity than Ar process gas is provided.

[0007]

In an experiment / prototype process for solving the above-mentioned problems, the present inventors have proposed that the magnetron sputtering method uses A
When the target is sputtered using ions heavier than r ions, that is, Kr, Xe, and Rn ions, the emission direction of the emitted sputtered particles is as shown in FIG.
It has been found that it has strong directivity in the vertical direction of the target plane. The same tendency was also observed when using a processing gas in which Ar ions were mixed with the above element ions.
Therefore, in the magnetron sputtering method, Kr gas, Xe gas, Rn gas, or a mixture of these gases with Ar gas is used as a processing gas , and a target gas is used .
A spa that travels in a direction normal to the substrate between the substrate and the substrate.
The Rukoto to place the collimator for selectively passing jitter particles, it is possible to solve the above problems, and it is possible to form a film excellent in bottom coverage.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a sputtering apparatus for realizing a sputtering method according to the present invention. In this sputtering apparatus, the magnetron 1
The target 103 is disposed on the semiconductor substrate 1 which is a substrate to be processed.
07 is held on a substrate holder (not shown).
Further, a collimator 106 for selectively passing vertical sputtered particles is disposed between the target 103 and the semiconductor substrate 107, and an exhaust gas communicating with a processing gas introduction unit 102 and a pump 105 is provided on an outer wall of the chamber. Mouth 1
04 is provided.

According to the present invention, a Kr gas, a Xe gas, a Rn gas, or a gas obtained by mixing these gases with an Ar gas is introduced from the processing gas introduction unit 102. As a result, plasma is generated, and the target 103 is sputtered. The sputtered particles generated here have strong directivity in the vertical direction unlike the case of the conventional example. The generated adhered particles reach the semiconductor substrate 107 through a hole opened in the collimator 106. This collimator 1
06, the directionality of the attached particles is further adjusted, and only the attached particles traveling in the normal direction of the semiconductor substrate surface reach the semiconductor substrate.

An embodiment in which Xe gas is introduced as a processing gas into the sputtering apparatus and plasma is generated by a magnetron to deposit Ti is described below. FIG. 2 shows that the sputtering method according to the present invention
FIG. 4 is a vertical cross-sectional view of the semiconductor device, showing a step of depositing a film in the order of steps. First, as shown in FIG. 2A, an element isolation region 202 is formed on a semiconductor substrate 201 by depositing a nitride film, performing lithography and etching, and performing selective oxidation. Next, a diffusion region 203 is formed on the semiconductor substrate 201 by a method such as an ion implantation method. Subsequently, an interlayer insulating film 204 is deposited by a chemical vapor deposition method, and a normal lithography technique and RIE (Reactive Ion Etching) are used.
By the method, as shown in FIG.
Then, a contact hole 205 for exposing the surface of the diffusion region 203 is opened.

The substrate is introduced into the sputtering apparatus according to the present invention shown in FIG. 1, and a Ti film is deposited using Xe gas as a processing gas. In this embodiment, since the Xe gas having a specific gravity larger than that of the argon gas is used as the processing gas, the traveling directions of the sputtered particles generated from the target are aligned, and the amount of the adhering particles after passing through the collimator is slightly reduced. Therefore, the film formation can be completed in a short time. At this time, since the direction of the particles toward the semiconductor substrate coincides with the normal direction of the substrate, as shown in FIG.
A Ti film 206 having a sufficient thickness is also deposited inside the contact hole having a large aspect ratio.

By performing a rapid heat treatment on the Ti film 206 deposited as described above, an S
A reaction layer 207 of i and Ti is formed. Thereafter, a TiN film 208 is deposited on the entire surface by a chemical vapor deposition method, and an aluminum film 209 is further deposited thereon, and is patterned by lithography and dry etching to form a wiring connected to the diffusion region 203.

In the semiconductor device formed as described above, a thick Ti film can be deposited at the bottom of the contact hole, so that stable electric characteristics can be obtained.
Also, in order to deposit the adhered particles through the collimator,
The ions of the processing gas do not directly reach the substrate, and damage to the substrate is significantly reduced. Further, since the generation of particles due to deposits on the collimator has been significantly reduced, the occurrence of defects due to this has also been drastically reduced.

[0014]

As described above, in the sputtering method according to the present invention, since a gas having a higher specific gravity than argon gas is used as a processing gas, the traveling direction of the adhered particles emitted from the target is in the normal direction of the target surface. Alignment improves the straightness of the adhered particles, prevents the adhered particles from being hindered by the collimator when passing through the collimator, and can form a good film in a short time even in a high aspect ratio contact hole. Become like Further, since the number of particles adhering to the collimator is drastically reduced, the target can be effectively used, and the generation of particles is reduced and the yield is improved. Further, since the substrate is not exposed to the plasma of the processing gas through the collimator, a film can be formed without damaging the substrate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sputtering apparatus for realizing a sputtering method according to the present invention.

FIG. 2 is a process cross-sectional view illustrating a method for manufacturing a semiconductor device using a sputtering method according to the present invention.

FIG. 3 is a graph showing directivity of sputtered particles by the sputtering method of the present invention and a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 chamber 101 magnetron 102 processing gas introduction unit 103 target 104 exhaust port 105 pump 106 collimator 107, 201 semiconductor substrate 202 element isolation region 203 diffusion region 204 interlayer insulating film 205 contact hole 206 Ti film 207 reaction layer of Si and Ti 208 TiN Film 209 Aluminum film

Claims (2)

(57) [Claims] A target is placed on a magnetron, and a substrate of a workpiece is placed facing the target.
Between the slot and the substrate in a direction normal to the substrate.
Collimator to selectively pass through sputtered particles
In sputtering method for performing sputter deposition by a sputtering method characterized by Ru with large gas specific gravity than Ar process gas. 2. A process gas comprising Kr gas, Xe gas, and Rn gas.
2. The sputtering method according to claim 1, wherein a gas or a mixed gas of these gases and an Ar gas is used.