JPH07331423A - Formation of thin film and device therefor - Google Patents

Abstract

PURPOSE:To stably form a thin film on a substrate in a specified thickness at the time of irradiating the surface of a target in a vacuum chamber with a laser beam to generate the target particle and to form a film of the target material on the substrate by using an excimer laser beam as the laser beam. CONSTITUTION:A holder 11 to which a substrate 6 having a step on its bottom is fixed and a target 7 as a film forming material opposed to the holder are arranged in a vacuum chamber 1, and the chamber 1 is evacuated by an evacuating system 4. An excimer laser beam 9 of 0.1-0.4mum wavelength is then emitted from an excimer laser beam source 2 to horizontally scan the target 7 surface, and a target particle 8 is generated. The substrate 6 is moved in the direction orthogonal to the emitting direction of the particle 8, and the film 8 of the target material having W/d<1 aspect ratio and a thickness of at least 1/2 of the depth (d) is stably formed on the bottoms of many contact holes 6b with the depth (d) of the substrate surface and width W, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the formation of a semiconductor element, and is particularly suitable for forming a film on a stepped portion such as a contact hole of a substrate or forming a magnetic film by aligning the directions of sputtered particles. Thin film forming apparatus and method thereof.

[0002]

2. Description of the Related Art There are several types of conventional thin film forming apparatuses, but there are a magnetron sputtering apparatus and an ion beam sputtering apparatus which are particularly characteristic for production. The substrate on which the thin film is formed is usually flat, but once the film is formed, as shown in FIG. 2, unevenness is formed in the film or after the contact hole of the semiconductor element is formed, the wiring film is formed in the contact hole. I have something to do. Conventionally, a film is also formed on the uneven step portion or the bottom portion of the contact hole by using a magnetron sputtering device. However, in recent years, the pattern size of the semiconductor element has become smaller, and the film thickness attached to the bottom of the contact hole has become smaller than the film thickness attached to the flat portion, and there has been a problem that a space is formed in the contact hole. The magnetron sputtering apparatus is disclosed in Japanese Patent Laid-Open No. 1-147063.

Therefore, an invention has been proposed to address this problem in an ion beam sputtering apparatus having directivity for sputtered particles. If the pattern size of the semiconductor element becomes smaller, from the pattern size of 0.5 μm of 16 Mbit DRAM to the pattern size of 0.3 μm of 64 Mbit DRAM, and to the pattern size of 0.2 μm of 256 Mbit DRAM, the ion beam sputtering method is used. However, problems similar to those of the magnetron sputtering method occur as described above.

On the other hand, as another thin film technique, there is a thin film formation such as a magnetic film which requires that the target particles fly in a constant direction. For this, a collimator is provided between the target and the substrate. There is a system in which the sputtered particles having a large divergence angle are attached to the collimator and are not deposited on the substrate.

[0005]

In the conventional thin film forming apparatus, in the magnetron sputtering method, as compared with the film thickness deposited on the flat portion, the film thickness deposited on the bottom of the contact hole or the like is deposited on the flat portion. There is a problem that it becomes thinner than the film thickness. The ion beam sputtering method has the same problem as the magnetron sputtering method when the pattern size of the semiconductor element is further reduced. On the other hand, for a thin film that requires directivity such as a magnetic film, if a collimator is provided in the magnetron sputtering method in which the divergence angle of sputtered particles is large, the film formation rate will be extremely low, and only a small film formation rate will be obtained from the beginning Also in the ion beam sputtering method, if a collimator is provided, the film forming speed becomes further smaller, and there was a big problem for production.

An object of the present invention is to provide a thin film forming apparatus and method capable of forming a film with a predetermined thickness on the bottom of a contact hole formed in a substrate.

[0007]

In order to achieve the above object, a thin film forming apparatus according to the present invention is provided with a laser source of laser light provided outside a vacuum chamber and an introduction window installed in the vacuum chamber. In a thin film forming apparatus provided with a target irradiated with laser light and a substrate holder for holding a substrate at a position where particles projected from the target are attached and forming a film on the substrate, at least a plurality of contact holes formed in the substrate The target particles are formed to have a predetermined thickness on each bottom.

The laser source of laser light provided outside the vacuum chamber, the target installed in the vacuum chamber and irradiated with the laser light through the introduction window, and the substrate held at the position where particles jumping from the target adhere In a thin film forming apparatus having a substrate holder for forming a film on a substrate, a laser source is formed by an excimer laser source, and at least a plurality of target particles formed on the substrate are ejected by excimer laser light. A configuration may be used in which a means for forming a film with a predetermined thickness is provided on the bottom of each contact hole.

Further, the substrate is held at a position where a laser source of laser light provided outside the vacuum chamber, a target installed in the vacuum chamber and irradiated with the laser light through an introduction window, and particles ejected from the target are attached. In a thin film forming apparatus having a substrate holder for forming a film on a substrate, a laser source is formed by an excimer laser source, and the target particles emitted in a certain direction by being irradiated with excimer laser light have a predetermined thickness. A configuration including a unit for forming a magnetic film may be used.

Further, the excimer laser source has a wavelength of 0.
It may be configured to generate excimer laser light of 1 to 0.4 μm.

The means for forming a film may be a scanning mechanism for moving the substrate holder together with the substrate in a direction substantially orthogonal to the target particles.

The film forming means may be an optical mechanism for scanning and moving the excimer laser light onto the target.

Further, a plurality of excimer laser generating sources may be provided and arranged at positions where the respective excimer laser lights are irradiated while being shifted from each other on the target.

Further, at least a plurality of contact holes may be formed to have an aspect ratio of 1 or less and to be formed at the bottom of each of the contact holes to have a thickness of at least ½ of the depth.

The semiconductor element is formed by using the thin film forming apparatus described in any one of the above.

Further, in the thin film forming method, a laser light source provided outside the vacuum chamber irradiates a target placed in the vacuum chamber through an introduction window to form a film on a substrate by particles projected from the target. In the thin film forming method, the laser source is formed by an excimer laser source and the target particles that are emitted by the excimer laser beam and fly out, at a predetermined depth at the bottom of each of at least a plurality of contact holes formed in the substrate. A film is formed.

A thin film forming method in which a laser beam emitted from a laser source provided outside the vacuum chamber is applied to a target arranged in the vacuum chamber through an introduction window to form a magnetic film on a substrate by particles protruding from the target In the above, the configuration may be such that the laser source is formed by the excimer laser source and the magnetic film is formed with a predetermined thickness by the target particles that are irradiated with the excimer laser light and fly out in a certain direction.

Further, the semiconductor element is formed by using the thin film forming method described in any one of the above.

[0019]

According to the present invention, the laser ablation method has extremely high directivity of target particles as compared with the magnetron sputtering method and the ion beam sputtering method. Further, since it is not necessary to generate plasma in the vacuum chamber, an excimer laser generation source is provided outside the vacuum chamber, and the excimer laser light is incident into the vacuum chamber through the introduction window. Therefore, the vacuum degree of the vacuum chamber is high, or Maintained in ultra-high vacuum. Therefore, the target particles that are irradiated with the excimer laser light and jump out from the target do not hit the residual gas in the vacuum, and the high directivity is maintained. For this reason, the target particles easily reach the bottoms of a plurality of contact holes having a very small pattern size, and a film having a predetermined film thickness is formed on each bottom by the film forming means. Further, since a collimator is not required, the sputtering speed of target particles is high, which is applied to a production machine and the production capacity is improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a laser source of laser light provided outside the vacuum chamber 1, a target 7 provided inside the vacuum chamber 1, and a fluorite stone provided in the vacuum chamber 1 facing the laser source. A thin film forming apparatus for forming a film on the substrate 6 including a substrate holder 11 for holding the substrate 6 at a position where particles projected from the target 7 are irradiated with the laser beam through the introduction window 5 of The source is formed by the excimer laser source 2, and the target particles 8 emitted by the excimer laser beam 9 and jumped out cause the step 6a formed on the substrate 6 and the bottoms of the plurality of contact holes 6b to have a predetermined thickness. The film forming means 10 and 12 are provided.

That is, the vacuum chamber 1 is evacuated by the vacuum evacuation system 4 via the gate valve 3 to maintain a high vacuum. Excimer laser light 9 having a wavelength of 0.1 to 0.4 μm, such as KrF or ArF, is generated from the excimer laser generation source 2 and is passed through the introduction window 5 to a target 7 formed of a material of Al, Al ₂ O ₃ or AlI _3. Irradiate. The binding energy of the target particles 8 is absorbed in the portion of the target 7 that is exposed to the excimer laser light 9, and the target particles 8 separate and fly out. This becomes ablation particles (sputter particles). The protrusion of the target particles 8 is a phenomenon in which the binding energy of the target particles 8 is absorbed and the target particles 8 are separated and scattered, and it is not a sputtering phenomenon in which the particles are sputtered from the target by the laser light. Alternatively, the directivity is extremely higher than that of the ion beam sputtering method. By arranging the substrate 6 at the position where the target particles 8 adhere, the substrate 6 is formed at the bottom of the step 6a shown in FIG. 2 and the contact hole 6b shown in FIG. It is possible to deposit a film.

An example of film formation is shown in FIG. FIG. 4 shows a state in which the contact hole 6b in FIG. 3 is enlarged to form a film. The pattern size of the contact hole 6b is, for example, 6
0.3 μm of 4 Mbit DRAM, or 256 Mbit D
Width W and depth d with 0.2 μm fine pattern size of RAM
Aspect ratio w / d is less than 1, for example 0.3
Below, the ratio c / a of the thickness a of the film formed on the surface to the thickness c of the film formed on the bottom is large in the McNetron sputtering method and the ion beam sputtering method, and the divergence angle of the sputtered particles is large and spreads over a wide range. Therefore, if a collimator is provided, sputtered particles also adhere to the collimator and the value becomes considerably smaller than 1. Therefore, a thick film having a predetermined thickness cannot be formed at the bottom of the contact hole. However, by using the laser ablation method, since the directivity of the target particles 8 is high, it is possible to form a thick film having a predetermined thickness of 1/2 or more of the depth d. Moreover, since the vacuum chamber can be made to have a high vacuum, the directivity is not deteriorated by being scattered by the residual gas in the vacuum. Further, since a collimator is unnecessary, the film forming speed is high and the productivity can be improved by applying it to a production machine.

Another embodiment of the present invention will be described with reference to FIG. According to the embodiment shown in FIG. 1, the directivity of the ablation particles is extremely high, so that the portion where a film can be formed is small. However, as shown in FIG. 5, the substrate 6 together with the substrate holder 11 is substantially orthogonal to the target particles 8. By providing a scanning mechanism (film forming means) 12 for scanning in the direction of scanning and scanning the target particles 8, it is possible to form a film on each contact hole or the like in a wide range of the substrate 6.

As another embodiment of the present invention, as shown in FIG. 6, a scanning reflecting mirror (optical mechanism) 10 for reflecting the excimer laser beam 9 is provided outside the vacuum chamber 1 so as to face the excimer laser generating source 2. The scanning mirror 10 is swung to scan the target with the excimer laser beam 9 to increase the irradiation area, and the film can be formed in a wide range of the contact holes of the substrate 6 in the same manner as described above. .

As another embodiment of the present invention, as shown in FIG. 7, a plurality of excimer laser generating sources 2a and 2b are provided, and excimer laser beams 9a and 9a are provided to different portions on the target through a plurality of introducing windows 5a and 5b. By irradiating 9b, it is possible to form a film over a wide area of the substrate 6 as described above.

As another embodiment of the present invention, the structure of any one of the above-mentioned embodiments is used, and by the target particles irradiated with the excimer laser light and ejected in a certain direction,
It is possible to form a thin film such as a magnetic film having a predetermined thickness at the bottom of each of the plurality of contact holes formed in the substrate, which requires that the flying direction of the ablation particles is constant. Since the formed film has extremely high directivity, it can exhibit high performance.

A thin film forming method as another embodiment of the present invention uses the constitution of any one of the above embodiments, and a semiconductor element uses any one of the above thin film forming apparatus or thin film forming method. It is assumed that the film is formed.

[0028]

According to the present invention, since the directivity of the target particles ejected by the excimer laser light is extremely good, it is possible to form a film having a predetermined thickness on the bottom of the contact hole or the like of the substrate. Further, the performance can be improved by forming a magnetic film.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating steps of the substrate shown in FIG.

FIG. 3 is a sectional view illustrating a contact hole of the substrate shown in FIG.

FIG. 4 is an enlarged partial cross-sectional view of the hole shown in FIG.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Excimer laser generation source 3 Gate valve 4 Vacuum exhaust system 5 Introduction window 6 Substrate 7 Target 8 Target particle 9 Excimer laser light 10 Reflecting mirror (optical mechanism) for scanning 11 Substrate holder 12 Scanning mechanism

Claims (12)

[Claims] 1. A laser generation source of laser light provided outside the vacuum chamber, a target installed in the vacuum chamber and irradiated with the laser light through an introduction window, and a position where particles protruding from the target are attached. In a thin film forming apparatus having a substrate holder for holding a substrate and forming a film on the substrate, forming a film with a predetermined thickness using target particles on the bottom of each of at least a plurality of contact holes formed on the substrate. A thin film forming apparatus. 2. A laser generation source of laser light provided outside the vacuum chamber, a target installed in the vacuum chamber and irradiated with the laser light through an introduction window, and a position where particles protruding from the target are attached. In a thin film forming apparatus comprising a substrate holder for holding a substrate on and forming a film on the substrate, the substrate is formed by the target particles which are formed by the excimer laser light source and are emitted by the excimer laser light. A thin film forming apparatus comprising means for forming a film with a predetermined thickness on the bottom of each of the at least a plurality of contact holes formed in. 3. A laser generation source of laser light provided outside the vacuum chamber, a target installed in the vacuum chamber and irradiated with the laser light through an introduction window, and a position where particles protruding from the target are attached. In a thin film forming apparatus having a substrate holder for holding a substrate and forming a film on the substrate, the laser source is formed by an excimer laser source and the target particles emitted in a certain direction by being irradiated with excimer laser light are used. A thin film forming apparatus comprising means for forming a magnetic film with a predetermined thickness. 4. The excimer laser source has a wavelength of 0.1 to 10.
4. The thin film forming apparatus according to claim 2, wherein the thin film forming apparatus emits 0.4 μm excimer laser light. 5. The film forming means is a scanning mechanism for scanning and moving the substrate holder together with the substrate in a direction substantially orthogonal to the target particles.
Alternatively, the thin film forming apparatus according to item 4. 6. The thin film forming apparatus according to claim 2, 3 or 4, wherein the film forming means is an optical mechanism for scanning and moving the excimer laser light onto the target. 7. The excimer laser generating source is provided in a plurality, and the excimer laser generating sources are arranged at positions where the respective excimer laser beams are irradiated while being shifted from each other on the target. Thin film forming equipment. 8. At least a plurality of contact holes,
8. The thin film forming apparatus according to claim 1, wherein the aspect ratio is formed to be 1 or less, and each bottom portion is formed to have a thickness of at least ½ of the depth. . 9. A semiconductor element formed by using the thin film forming apparatus according to claim 1. 10. A method for forming a thin film, wherein laser light is emitted from a laser generation source provided outside a vacuum chamber to a target placed in the vacuum chamber through an introduction window, and particles ejected from the target form a film on a substrate. In the above, the laser source is formed by an excimer laser source, and the target particles emitted by the excimer laser light and ejected form a bottom portion of at least a plurality of contact holes formed in the substrate with a predetermined thickness. A method for forming a thin film, which comprises forming a film. 11. A laser light source provided outside the vacuum chamber irradiates a target arranged in the vacuum chamber through an introduction window, and a magnetic film is formed on a substrate by particles projected from the target. In the thin film forming method, the laser source is formed by an excimer laser source, and a magnetic film is formed with a predetermined thickness by target particles that are irradiated with excimer laser light and fly out in a certain direction. Thin film forming method. 12. A semiconductor device formed by using the thin film forming method according to claim 10.