JPH0499173A - Sputtering system - Google Patents

Abstract

PURPOSE:To secure the good coverage of minute steps without significantly sacrificing the capacity in the magnetron sputtering system by providing an ion beam sputtering means and a means for adjusting the angle of target. CONSTITUTION:A gaseous Ar inlet pipe 8, a vacuum pump 4, a cathode 9 hold ing a target 1 and contg. a coil 6 and connected to a bellows 10, and an ion generating chamber 14 to irradiate the target 1 with Ar ion are provided to a vacuum vessel 3 in which a semiconductor substrate 2 is placed. An angle adjusting part 12 is furnished to the cathode 9, and the incident angle of the ion beam from the chamber 14 to the target 1 is adjusted. The ion beam from the chamber 14 strikes the target 1 and is reflected toward a semiconductor substrate in the case of ion beam sputtering, and the angles of incidence and reflection are equalized by adjusting the angle of the target 1 by the adjusting part 12. Meanwhile, the angles of incidence and reflection are paralleled with the substrate 2 in the case of magnetron sputtering.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a sputtering device.

[Conventional technology]

A conventional sputtering apparatus is constructed as shown in FIG. The operation will be explained below.

First, after evacuating the vacuum chamber 3 to a high vacuum using the vacuum pump 5, Ar gas is introduced from the Ar gas introduction pipe 8 at 10-2 to 1
0-' Torr, and a negative DC voltage is applied to the target material 1 held by the cathode 9 by the DC power source 7. At this time, if a magnetic field is generated by the coil 6 at the same time, a magnetron discharge is generated on the surface of the target material 1, and Ar+ ions are incident on the surface of the target material 1, causing sputtering. The target material sputtered by Ar'' ions moves in the vacuum chamber, reaches the semiconductor substrate 2, and is deposited thereon.

That is, film formation is performed by generating particles of the target material 1 by sugenetron discharge and allowing them to reach the semiconductor substrate 1.

[Problem to be solved by the invention]

In this conventional sputtering apparatus, the particles of the target material 1 generated by sputtering move from the surface of the target material toward the semiconductor substrate 2, but in order to maintain the discharge, the particles of the target material 1 move from the surface of the target material to the semiconductor substrate 2. Since the vacuum chamber 3 is filled with Ar gas at a pressure of Torr, the particles of the target material 1 collide with the Ar gas atoms and are scattered.

That is, as shown in FIG. 4(a), Ar gas atoms 2
5, the angle of incidence of the target material particles 24 onto the semiconductor substrate 22 is random. Since the moving direction of the target material particles 24 has a horizontal component with respect to the semiconductor substrate 22, the target material particles 24 also adhere to the side walls of the step 23 on the semiconductor substrate 22, as shown in FIG. 4(b). As such, an overhang portion 27 is generated in the deposited film 26. As the shape of the step becomes finer, the overhang serves to thin the deposited film 26 at the bottom of the step. In particular, film deposition in contact holes becomes more difficult as the target material particles 24 become finer if their motion components include a component in a direction horizontal to the substrate.

That is, as shown in FIG. 4(c), a break in the film occurs at the bottom of the contact hole.

On the other hand, vacuum evaporation, ion beam sputtering, etc. are available as film deposition methods that provide particle movement methods for film deposition, but these methods have low film deposition speeds, are not suitable for single-wafer processing, and are difficult to apply to the side surfaces of steps. It has drawbacks such as poor film adhesion and poor step coverage.

[Means to solve the problem]

The sputtering apparatus of the present invention sputters a target material provided in a vacuum chamber by magnetron discharge to form a thin film on a semiconductor substrate held in the vacuum chamber. The target material is provided with means for irradiating the material with Ar ions to perform ion beam sputtering, and means for adjusting the angle of the target material.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In FIG. 1, the vacuum chamber 3 into which the semiconductor substrate 2 is placed is
an Ar gas introduction pipe 8 connected to the Ar gas valve 11; a vacuum pump 4 connected to the conductance adjustment valve 5;
A cathode 9 that holds the target material 1, contains a coil 6, and is connected to a bellows 10 is provided. Furthermore, this vacuum chamber 3 is provided with an ion generation chamber 14 for irradiating the target material 1 with Ar ions.

This ion generation chamber 14 includes an ion source main valve 2.
1, an Ar gas introduction tube 16 connected to an ion source Ar gas valve 17, a filament 18, one discharge electrode, an ion extraction TFI 15, and a beam scanning mold. 8i! 13 are provided.

Further, the cathode 9 is provided with an angle adjustment section 12 consisting of a gear, a motor, etc., and is configured to be able to adjust the incident angle of the ion beam from the ion generation chamber 14 with which the target 1 material is irradiated. These operations will be further explained below.

The vacuum chamber 3 for film formation is 10-7 Torr with a vacuum pump 4.
It is evacuated to r level. Further, the ion generation chamber 14 is also evacuated by the ion source vacuum pump 2o.

Ion beam sputtering can be achieved as follows.

Discharge electrode 19 inside the ion generation chamber 14 after evacuation
Ar gas is introduced from the Ar gas introduction pipe 16 through the Ar gas valve 17 at a pressure of 10-5 to 10-4 Torr. Then, while heating the filament 18 and generating thermoelectrons, a voltage is applied between the filament 18 and the discharge type [i19 to cause an arc discharge. Accelerate by applying a voltage of Then, the Ar'' ion beam is scanned over the target material 1 by the beam scanning electrode 13, and sputtering can be realized.At this time, the vacuum chamber 3 is
It is maintained at a vacuum of 0-7 to 10-' Torr.

Moreover, magnetron sputtering can be realized as follows.

Ar gas is introduced from the Ar gas introduction pipe 8 through the Ar gas valve 9 into the vacuum chamber 3 after evacuation.
"Torr r is introduced, and the target material 1 is
When a negative voltage of 400 to 700 cm is applied to the target material from the DC power supply 7 while a magnetic field is formed on the surface of the target material, magnetron discharge occurs, and sputtering can be realized by the impact of Ar+ ions generated by the discharge.

During ion beam sputtering, the angle of the target material 1 is determined by the incident angle and reflection angle when the ion beam from the ion generation chamber 14 hits the target material 1 and is reflected in the direction of the semiconductor substrate, as shown in FIG. Adjust so that they are the same. Further, during magnetron sputtering, each angle is adjusted by the angle adjustment unit 12 so that it is parallel to the semiconductor substrate 2.

According to this embodiment configured in this way, ion beam sputtering and magnetron sputtering can be freely switched by controlling the power supply and Ar gas introduction tube connected to the ion generation chamber 14 and the vacuum chamber 3, respectively. I can do it.

Next, an example of forming an aluminum film with a thickness of 1 μm according to this embodiment will be described with reference to FIG.

As shown in FIG. 2(a), an aluminum film 26A with a thickness of 0.3 μm is first formed by ion beam sputtering on a semiconductor substrate 22 on which an opening is formed in an insulating film or the like and a step 23 is formed.
A film is formed to a thickness of .

Subsequently, as shown in FIG. 2<b>, the remaining 0.6 μm aluminum film 126A is formed by magnetron sputtering.

As a result, the aluminum film 26A was deposited by ion beam sputtering to the bottom of the step 23 without overhanging, and the step breakage that conventionally occurred did not occur. Also, the thickness of the aluminum film formed by ion beam sputtering is 0.
．． Because the remaining aluminum film is as thin as 3 μm and is formed by magnetron sputtering, which has a high deposition rate, processing capacity was significantly improved compared to conventional ion beam sputtering, which uses only ion beam sputtering to deposit the film.

In the above example of forming an aluminum film, the angle of the target material 1 was fixed so that the incidence of the target material particles on the semiconductor substrate during ion beam sputtering was perpendicular to the substrate. The aluminum film was formed by changing the angle of incidence of the target material particles during sputtering so that the angle of incidence of the target material particles ranged from -15° to +15° with respect to the perpendicular to the substrate.

Angular scanning was performed on two axes perpendicular to each other with periods of 5 seconds and 0.5 seconds, respectively. At this time, the scanning period of the Ar'' ion beam is 115 times the angular scanning period of the target material 1.
I made it below 0.

The aluminum film was formed by ion beam sputtering to a film thickness of 0.3 μm, and by magnetron sputtering to a remaining film thickness of 0.6 μm. As a result, the aluminum film was deposited not only on the bottom of the step but also on the side walls during sputtering with IonBee 11, and step coverage was further improved compared to when the angle of the target material was fixed.

〔Effect of the invention〕

As explained above, since the sputtering apparatus of the present invention has an ion beam sputtering mechanism and a magnetron sputtering mechanism, after ensuring the deposition of a film at the bottom of a fine step on a semiconductor substrate by ion beam sputtering, the sputtering apparatus has a high deposition rate. Since a film can be deposited to a predetermined thickness by magnetron sputtering, it has the effect of ensuring good step coverage in fine step shapes without sacrificing too much processing capacity.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a cross-sectional view of a semiconductor chip to explain the case where an aluminum film is formed in this embodiment, and FIG. 3 is a configuration of a conventional magnetron sputtering apparatus. 4 are cross-sectional views of a semiconductor chip for explaining a case where a film is deposited using a conventional magnetron sputtering apparatus. 1... Target material, 2... Semiconductor substrate, 3...
Vacuum chamber, 4... Vacuum pump, 5... Contactance adjustment valve, 6... Coil, 7... DC power supply, 8...
... Ar gas introduction pipe, 9 ... Cathode, 10 ... Bellows 11 ... Ar gas valve, 12 ... Angle adjustment section, 13 ... Beam scanning electrode, 14 ... Ion generation chamber, 15... Ion extraction electrode, 16... Ar
Gas introduction pipe, 17...Ar gas valve for ion source, 1
8... Filament, 19... Discharge electrode, 20...
- Vacuum pump for ion source, 21... Main valve for ion source, 22... Semiconductor substrate, 23... Step, 24
... Tarp material particles, 25... Ar gas atoms,
26...Deposited film, 26A...Aluminum film, 27...
overhang part.

Claims (1)

[Claims] In a sputtering apparatus that sputters a target material provided in a vacuum chamber by magnetron discharge to form a thin film on a semiconductor substrate held in the vacuum chamber, the target material connected to the vacuum chamber is irradiated with Ar ions. means for performing ion beam sputtering;
A sputtering apparatus comprising: means for adjusting the angle of the target material.