JPH01149957A - Thin film forming apparatus and thin film forming method - Google Patents

Abstract

PURPOSE:To stably fill up the open cells of a large-area substrate by alternately carrying out the deposition on the substrate and etching respectively in a film forming chamber and in an etching chamber, and making the incident angle of the current of the particles to be deposited larger than the infiltrating angle of the etching particles. CONSTITUTION:A substrate holder 11 contg. a heater 12 and a target 17 are arranged in a vapor deposition chamber 7, an etching substrate holder 20 and an ion source 23 are arranged in an etching chamber 8, and both chambers 7 and 8 are allowed to communicate with each other through a valve 6. The substrate 3 is introduced into the vapor deposition chamber 7 from a spare chamber 1 through a valve 5, the particles of the film forming material of the target 17 are deposited on the substrate 3, the substrate 3 is transferred to the etching chamber 8 through the valve 6, and the substrate 3 is etched by the ion beam from the etching source 23. The deposition on the substrate 3 and etching are alternately carried out. In this case, the incident angles of the particle current and ion beam are controlled to <=+ or -10 deg., and the incident angle of the particle current is made larger than the infiltrating angle of the ion beam. The energy of the etching ion is preferably controlled to <=500eV.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor manufacturing apparatus and a thin film forming method,
In particular, the present invention relates to a thin film forming apparatus and a thin film forming method that can form a thin film suitable for forming a thin film when a step such as a groove or a hole exists on a substrate.

[Conventional technology]

Conventional wiring for semiconductor devices is often formed by forming predetermined openings in an insulating film formed on a substrate and depositing a conductive film thereon.

In particular, the first method for embedding a conductive film inside the opening is to perform sputter deposition from a substantially perpendicular direction and at the same time from an oblique direction to the substrate at high acceleration of 5 KV, as shown in Japanese Patent Application Laid-Open No. 61-172327. A method of irradiating an ion beam with voltage is known. In this method, part of the metal particles adhering to the upper end of the step such as the hole is etched from an oblique direction, so that the so-called shadowing effect does not occur and the particles are efficiently deposited inside the hole. It is said that In addition, in this example, in order to improve the efficiency of embedding into the hole, the particles flying out from the sputter deposition source are so directional that they do not adhere to the side walls of the hole, but only to the bottom of the hole, and are directed vertically. It is stated that it is necessary to enter the In order to achieve this, although not specifically specified, a special sputtering source or the like is required, which has improved directivity by providing a filter in front of the target.

Second, a method disclosed in Japanese Patent Laid-Open No. 62-26822 is known. In this method, as in the first method, deposition of particles serving as a material for film formation and etching are performed simultaneously or alternately. As in the first method, the direction of incidence of the deposited particles is approximately vertical, and the angle of incidence is within 10 degrees. 10
One example of this restriction is that in vacuum evaporation and ion stream sputtering (ion beam sputtering), which are particle sources, the ejected particles are not completely parallel, and dispersion of about ±10 degrees is avoided. It corresponds to the fact that it is not vertical, and it means that it is substantially vertical. The difference from method 1 is that the incidence of the ion stream for etching can be almost perpendicular (reverse sputtering, etc.). That is, the second method is characterized in that both particle deposition and etching are performed substantially vertically.

In contrast, in the first method, particles are deposited almost vertically;
The difference is that etching is performed under conditions of a large wrap-around angle.

[Problem that the invention seeks to solve]

However, semiconductor manufacturing equipment and thin film forming methods using these methods have the following problems.

In the first case, an example will be described in which sputter deposition and ion beam etching are simultaneously performed on the substrate. Generally, in order to perform sputter deposition in a stable state, it is desirable that the gas pressure at least during sputtering be in the range of 10-1 to 10-8 Torr. In addition, to obtain a stable ion beam from the ion source, the gas pressure should be set at 10'4 to 10'Torr.
need to be used in Therefore, in order to perform sputter deposition and ion beam irradiation simultaneously, it is necessary to operate both in an unstable region, which causes problems such as a decrease in film formation speed and film quality. In addition, it is necessary to have a mechanism to arbitrarily change the ion beam sputtering source, etc.
The device structure also becomes complicated. In the second method, vacuum evaporation or ion beam sputtering is used to make the deposited particles perpendicularly incident. First, when using the vacuum evaporation method, the area of the melted material for the deposited particles to evaporate is small, so it is difficult to make the deposited particles incident on a large substrate at a wraparound angle of less than 10 degrees. It is. To avoid this, increasing the distance between the deposition source and the substrate will reduce the deposition rate. Therefore, it is not suitable for application to large area substrates. When the ion beam sputtering method is used as the vapor deposition source, the size of the beam source is 10 inches or more, and the directionality of the deposited particles is also improved. Generally, an ion beam sputtering source with a diameter equal to or larger than that of the substrate used is used. In the second method, reverse spatter (sputter etch)
Alternatively, sputter etching using an ion beam source is said to be suitable.

When inverse sputtering is used as an etching method, the evaporation source operates stably at 10-5 to 10"-'Torr, and the inverse sputtering operates at 10-1 to 10-'Torr, so the first method is Similarly, the problem of unstable operation occurs.Also, when ion beam sputtering is used for etching, the evaporation source and the ion beam source must be installed almost on the vertical line of the substrate.Both require a fairly large volume. This makes it an extremely complicated device, making it impractical.

As described above, in all of the conventionally known methods, the particles for film formation must be incident on the substrate from the perpendicular direction, which limits the scope of application or complicates the apparatus. Furthermore, no consideration was given to the fact that it would be difficult to obtain stable operation because the evaporation source and the etching source were installed in the same vacuum chamber.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new film forming apparatus and method that allows stable filling of holes and the like and eliminates restrictions on the area of the substrate to which the film is applied.

[Means for solving problems]

The purpose of the above is to provide an apparatus that has independent chambers for stable and well-controlled deposition and etching of particles for film formation, and that allows substrates to be transported between the vacuum chambers without exposing them to the atmosphere. This is accomplished by alternating deposition and etching. In addition, by setting the particle energy for etching to 0.5 KeV or less, a film with excellent embedding properties can be formed.

As in the conventional technology, the incidence of the deposited particles is set perpendicularly (the wraparound angle is 51
It is not necessary that the etching particle angle is not perpendicular (0 degrees) and can be applied to large-area substrates.
wraparound angle > 10 degrees) is required. The turning angle of the etching particles may be within the range of the turning angle of the deposited particles.

The reason for being able to solve the problem stated in the first method of the prior art that the incidence of deposited particles must be vertical is as follows.

That is, in the first or second method, the energy of the etching particles was 2 to 5 KeV, whereas in the present invention, the energy of the etching particles was 0 to 5 KeV.
．． The difference is that it is 5 KeV or less.

The inventors found that when the energy of etching particles is high, the embedding characteristics generally tend to deteriorate, but by lowering the energy to 0.5 K e V or less, the embedding characteristics were significantly improved, which was superior to the conventional etching characteristics. We have found that various controls can be removed.

[Effect]

In order to carry out deposition and etching alternately, a co-deposition chamber and an etching chamber are provided as shown in FIG. 1, and a preliminary evacuation chamber may also be provided if necessary. The deposition chamber and the etching chamber are connected by a mechanism for transporting the substrate. When transferring a substrate, it is generally suitable to make the pressure in both chambers almost equal, or to transfer while maintaining a pressure difference by using a differential pumping mechanism or the like. A normal sputtering source may be used as the vapor deposition source. In this case, the effective wrap-around angle of the particles is considered to be 45 degrees or more. In addition, when using a vacuum evaporation source as the evaporation source,
It is not necessary to install it in a direction perpendicular to the substrate; for example, in order to improve film thickness uniformity, it may be installed at a predetermined angle and rotate the substrate or evaporation source. The wraparound angle of the etching particles may be larger than 10 degrees and smaller than the wraparound angle of the deposited particles. If the encircling angle of the etching particles is less than 10 degrees, the bottom of the hole may be damaged. When the wrap-around angle greatly exceeds that of the deposited particles,
A cavity may be formed inside the hole. The necessary embedding characteristics can be obtained if the energy of the etching particles is 0.5 KaV or less, but it was found that when the energy of the etching particles is 0.2 KeV or less, there is no damage to the substrate and extremely good embedding characteristics can be obtained. .

Further, since it is not necessary to carry out vapor deposition from the vertical direction, two or more vapor deposition sources may be installed inside the vacuum chamber. In this case, a film with better uniformity can be obtained by forming the film by rotating the substrate. Using a device with this configuration, for example, A Q / Ta
/AQ-like layered films and alloys (AQ-Ta) can be formed. These laminated films and alloy films are seen as promising materials for obtaining wiring that is resistant to migration.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 Fig. 1 is a configuration diagram of an apparatus that best represents the features of the present invention.6 Fig. 2 is an example of a schematic cross-sectional view of an opening when vapor deposition and etching are performed alternately five times. It is. A Si substrate 3 with a hole of 1 μm in diameter and an aspect ratio of 1 is placed on the substrate holder 2 in the preliminary chamber 1 . Valve 4 is opened using a vacuum pump inside preliminary chamber 1 until the residual gas pressure reaches I x 10-'
Exhaust the air so that the pressure is below Torr. At this time valve 5
, 6 are closed, and the deposition chambers 7., 6 are closed. The etching chamber 8 is opened using a vacuum pump through valves 9 and 10.
It is evacuated to below orr. Preparatory room l is lXl0
-'Torr or less, the valve 4 is closed, the valve 5 is opened, and the substrate 3 is transferred to the substrate boulder 11 in the deposition chamber 7. The substrate holder 11 is maintained at a predetermined temperature (for example, 200° C.) by an internal heater 12. Close the valve 5 and open the deposition chamber 7.
Evacuation is performed until the internal pressure becomes less than I x 10-6 Torr. After that, Ar gas is introduced by opening the valve 13, and the valves 9 and 13 are adjusted so that the gas pressure becomes 5 mt orr. For example, the switch 14 is connected to the high frequency power source 15 side and a power of 3.8 W/+J is applied to sputter target material AQ17.

In this example, a step was added in which the shutter 18 was closed before sputtering and discharge was performed. This step has the effect of removing impurities and adsorbed gas on the target surface. After that, open Jatsubu 18.

Note that the substrate holder 11 may be rotated at about 20 rpm by the motor 19 in order to improve the AQ film thickness distribution. The film was formed to have a predetermined thickness, for example, 0.4 μm. A cross-sectional view of the sample at this time is shown in FIG. 2(b). In this example, a sample was used in which a 1.0 μm hole was opened in a 1.0 μm insulating film on a substrate.

Next, the deposition chamber 7 is evacuated until the pressure reaches 10-BTor or less. Thereafter, the valve 6 is opened and the substrate 3 is placed in the etching substrate holder 20, and then the valve 6 is closed. The etching substrate has an angle θ of 1 with respect to the direction of incidence of the ion beam.
Can be changed from 0 to 90 degrees.

Here, θ=30 degrees. This board 20 is connected to the motor 2
2, rotates at 15 rpm. The acceleration voltage of the ion source 23 is set to 500 V, the current is set to 100 mA, and the degree of vacuum in the etching chamber 8 is set to 0 when the substrate is irradiated with the ion beam.
, 2 m Torr, and after etching the film to a thickness of 0.2 μm, the pressure was evacuated to 1 O-8 Torr or less. A cross-sectional view of the sample at this time is shown in FIG. 2 (Q).

The valve 6 is opened, the substrate 3 is transferred to the substrate holder 13, and the vapor deposition and etching are repeated five times in the same manner. At this time, the structure progressed from FIG. 2(Q) to FIG. 2(i), the pores were filled, and a 1 μm thick film was formed. By using this apparatus and method, even if there is a difference in the degree of vacuum (conditions) during operation of sputter deposition and ion beam etching, deposition and etching can be performed alternately stably and with good controllability. Since the angle 0 of the etching substrate holder 20 in the etching chamber 8 can be changed, even when the type of vapor deposition material changes, the angle of the ion beam going around the surface of the substrate 3 mounted on the holder can be optimized. Furthermore, since vapor deposition and etching can be carried out without exposing the substrate to the atmosphere, a high-quality film can be formed without forming an oxide film or the like between multiple thin film layers.

Example 2 In the above example, the vapor deposition chamber 7 was provided with Afl and Ta targets. Two cathodes are installed (the second target is not shown), and the AQ cathode is first discharged to deposit a film of 0.3 .mu.m, followed by 0.15 .mu.m ion beam etching. At this time, the structure shown in FIG. 2(b) is obtained. Next, a 0.3 μm film is deposited using a Ta cathode (not shown), and 0.15 μm ion beam etching is performed in the same manner. Repeat the above steps a predetermined number of times to deposit AQ.
Etching was performed four times each (FIG. 3, 120', 121').

124', 125') and Ta vapor deposition and etching twice (FIG. 3, 122'', 123') are shown in FIG. 3.

By using this apparatus, not only can the effects of Example 1 be obtained, but also films of different materials can be formed in layers on the substrate and in the openings with good controllability.

〔Effect of the invention〕

By separating the deposition chamber and etching chamber, stable deposition and etching can be performed even if there are differences in gas pressure (conditions) during sputter deposition and etching, and these two processes can be performed alternately under predetermined conditions. By performing this step, the conductive film can be embedded in the opening having an aspect ratio of 1 or more. Furthermore, by using a plurality of vapor deposition sources, a layered film can be formed within the opening. The inside of the opening has a laminated structure, such as A Q / T a, which is said to be resistant to migration.
/AQ structure, a highly reliable connection can be obtained.

In addition, although AQ or the combination of AQ and '1'a was described in the embodiment, there is no particular restriction on the selection of metal materials, and examples include AQ, Ti, W, Mo, Cr, and Zr.

Other materials such as Hf, Go, Cr, Cu or alloys thereof, or Si or N of these metals or alloys
It may also be a compound with.

Although a sputter source has been described as the vapor deposition source, other ion beam sputtering sources, heated vapor deposition sources, etc. may also be used.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams for explaining the present invention in detail. 1... Preparation room, 2... Board holder, 3... Board, 4
,5゜6.9,10,13.24... valve, 7...
- Vapor deposition chamber, 8... Etching chamber, 11... Substrate holder, 12... Heater, 14... Changeover switch, 1
5...High frequency power supply, 16...DC power supply, 17...
Target material, 18...Shutter, 19.22...
Motor, 20...Etching board holder, 21...
- Cooling water, 23... Ion source, ゛ 100... Substrate, 101... Insulating film, 102... First evaporated aluminum, 102'... Etched aluminum, 102', 103' , 104'. 106'... Remaining aluminum, 103... Second
Double evaporation aluminum, 104... Third evaporation aluminum, 120', 121', 124', 125'.
... Remaining aluminum, 122', 123'... 1st hole (g) 2nd (d-) (e,) <f) 2nd drawing) (generation) 3rd hole

Claims (1)

[Scope of Claims] 1. A thin film forming chamber having a source for generating particles or ions of at least one type of film forming material and an etching chamber having an etching mechanism, and alternately performs vapor deposition and etching on a substrate. 1. A thin film forming apparatus characterized by having a function capable of. 2. The thin film forming apparatus according to claim 1, wherein the source for generating the particles is any one of a sputter evaporation source, a heating vacuum evaporation source, or an ion beam sputtering source. 3. The incident angle of the particle stream to be deposited on the substrate surface and the ions or particles for etching onto the substrate are both greater than ±10 degrees, and the incident angle range of the particle stream to be deposited is equal to or greater than the encircling angle of the etching particles. A thin film forming method characterized by: 4. The thin film forming method according to claim 3, wherein the energy of the ions or particles for etching the surface of the substrate for forming the thin film is 500 eV or less.