JPH02224327A - Process and device of conductive film formation - Google Patents

Abstract

PURPOSE:To enable a film in stable quality to be formed by a method wherein, after forming nuclei on the surface of a work by irradiating the work with the fourth higher harmonics of YAG laser in organic metallic gas atmosphere, a conductive film is deposited on the nuclei formed part of the work by irradiating the said part with the second harmonics of the YAG laser. CONSTITUTION:A work is irradiated with the fourth higher harmonics omega4 of. YAG laser in an organic metallic gas atmosphere so as to form nuclei on the surface of the work by photodissociation. That is, the organic metallic gas is photodissociated by the fourth higher harmonics omega4 irradiation so as to form the nuclei. Since the nuclear formation process is performed by the photodissociation of organic metallic gas adsorbed on the substrate 6, the nuclei can be stably formed extending over the surfaces of different metals. Then, the substrate 6 is locally heated by the irradiation with the second higher harmonics omega2 following after the fourth higher harmonics omega4; the nuclei formed part is irradiated with the second higher harmonics omega2; and the nuclei are grown by thermocracking the organic metallic gas so as to deposit a metallic film 23. Through these procedures, a conductive film in stable quality can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a conductive film forming method and a conductive film forming apparatus for forming a conductive film on a substrate using laser light.

(Prior Art) D and J are methods of locally forming a metal film on a substrate as a workpiece using laser light.

1. A method of forming metal wiring using metal carbonyl and visible laser light proposed by IEhrllch et al.
There is a Japanese Patent Application Laid-Open No. 62-290874).

In addition, aluminum patterning technology using KrF excimer laser and triisobutyl aluminum by G. S. Lligashi et al. (A, P, L, 48(16), 2
1-Apr-19gB, P, 1051-1053). The method of Ehrlich et al. is a method in which wiring is formed by irradiating an Ar◆ laser onto a substrate placed in metal carbonyl vapor to locally thermally decompose the metal carbonyl.

The method of Htgashi et al. is a method in which a nucleus is formed by irradiating an excimer laser onto a substrate heated and held in a trip-chill aluminum atmosphere, and after the laser irradiation is stopped, the aluminum film is patterned by thermal decomposition.

Ebr that forms a conductive film only by heating with the visible laser described above
In order to form a stable wiring film using the method of llch et al., stable heating, that is, uniformity of the material on the substrate surface, is a necessary condition. It was not possible to form a conductive film.

In addition, since the method of G, S, Hlgashi et al. utilizes nucleation by photodissociation of excimer laser (ultraviolet light), it is possible to locally generate gold on a substrate whose surface is made of two or more types of materials. Although it is possible to form a non-nucleated film, it is necessary to uniformly heat the entire substrate, and since this method utilizes the difference in growth rate between nucleation and non-nucleation areas, the tolerance to substrate temperature is limited. Since the range is narrow, substrate temperature control is strict, and since a two-step process is required, throughput is low and productivity is low.

(Problem to be solved by the invention) A method for forming a conductive film on a substrate using laser light is as follows:
Various methods have been proposed, but all of them require temperature control to constantly heat the substrate, making it difficult to form a film over two or more types of materials. In addition, there was a drawback that many processes were required for film formation, and productivity was low.

The present invention has been made with attention to the above-mentioned problems, and an object of the present invention is to provide a conductive film forming method and a conductive film forming apparatus that do not require temperature control of a substrate and have high productivity.

[Structure of the invention]

(Means for solving the problem) (1) In the first step, the workpiece is irradiated with the fourth harmonic of a YAG laser in an organometallic gas atmosphere to form a nucleus on the surface of the workpiece. A method for forming a conductive film, comprising irradiating the second harmonic of a YAG laser onto the portion irradiated with the fourth harmonic in the second step to chemically grow a conductive film on the nucleation portion of the workpiece.

(2) A YAG laser oscillation section is provided, a harmonic conversion section is provided that converts the laser light from the YAG laser oscillation section into a composite light of a second harmonic and a fourth harmonic, and the synthesis from this harmonic conversion section is provided. A prism that separates light into a second harmonic and a fourth harmonic is provided, and a prism support mechanism that rotatably supports this prism is provided, and the second harmonic and fourth harmonic that are separated by the prism are provided. A condensing optical system is provided to focus the light on different points on the surface of the workpiece, and an organometallic gas supply means is provided to supply an organometallic gas to the processing section, and the workpiece is held and the fourth harmonic is The second irradiation position
A conductive film forming apparatus is provided with a table that is driven and controlled in the X-Y direction so that the harmonic irradiation position is tracked.

(Function) (1) YAG on the workpiece in an organometallic gas atmosphere.
After irradiating the fourth harmonic of a laser to form a nucleus, a conductive film can be chemically grown by irradiating the second harmonic of a YAG laser to the nucleation area.

(2) The laser beam oscillated from the YAG laser oscillation unit is converted into a composite light of the second and fourth harmonics by the harmonic conversion unit, and this composite light is converted into the second and fourth harmonics by a prism.
The two types of harmonics are focused by a condensing optical system onto the surface of the workpiece to which the organometallic gas has been supplied, with a distance maintained between them, and the table is driven. The processing section can be moved. Further, by rotating and adjusting the prism support device, the irradiation position of the second harmonic and fourth harmonic laser beams can be changed.

(Example) An example of the present invention will be described with reference to the drawings. The conductive film forming apparatus 1 shown in FIG. 1 mainly consists of a laser oscillation section 2, a harmonic conversion section 3, a prism 4, a condensing optical system 5, and a table 7 that holds a substrate 6 as a workpiece. ing.

The laser oscillation section 2 is a YAG laser device,
A high reflection mirror 9 and an output mirror 10 face each other at the end of the laser rod 8, and the output mirror 10 and the YAG
A Q switch 11 is inserted between the rod 8 and the rod 8.

A flash lamp 12 is provided on the side surface of the YAG port 8 so as to face each other. The laser oscillation unit 2 configured in this way has a Y wavelength of 1.06 μm (infrared light).
The AG laser beam ωl is oscillated.

A harmonic conversion section 3 is provided on the output optical path of the laser beam from the laser oscillation section 2.

This harmonic conversion section 3 includes a first conversion element 13, a second conversion element 14, which will be described later, and a reflection surface tilted at a predetermined angle between the first and second conversion elements 13, 14. The dichroic mirror 15 is inserted toward the 1 conversion element 13 side.

The first conversion element 13 converts the YAG laser beam ωl of a wavelength of 1.06 μm output from the YAG laser oscillation unit 2 into 5
It is configured to convert the second harmonic wave (SHO) ω2 having a wavelength of 32 nm and the oscillation wavelength light ω1 into a composite light ω1+ω2 and output it.

This combined light ω1+ω2 is such that the respective wavelength lights ω1°ω2 are emitted onto the same optical axis.

Then, the dichroic mirror 15 transmits the synthesized light ω
] When +ω2 is incident, the oscillation wavelength light ω1 is specularly reflected,
Only the second harmonic ω2 is transmitted.

The second harmonic ω2 that has passed through the dichroic mirror 15 in this way is transmitted through the second conversion element 14, so that a composite light ω2+ω4 of the second harmonic ω2 and the fourth harmonic ω4 having a wavelength of 266 nm is formed on the same optical axis. It is designed to output .

Then, the combined light ω2 emitted from the second conversion element 14
+ω4 is made incident on the prism 4. This prism 4 is, for example, an image rotating prism formed as shown in FIG. It is supported by a mechanism 16 so that it can be rotated in the direction of arrow T. Here, when the prism 4 is rotated, for example, by 180', the irradiated laser beam is rotated by 360'. In other words, the laser beam irradiated onto the substrate 6 is rotated by an angle twice as large as the rotation operation angle. In the prism 4, when the composite light ω2+ω4 enters from the entrance surface 4a and exits from the exit surface 4b, it is separated into a second harmonic ω2 and a fourth harmonic ω4. This emitted light ω2. ω4 is configured such that each optical axis is emitted at a predetermined distance. Then, by operating the prism support mechanism 16 to adjust the rotation of the prism 4 in the direction of arrow T, for example, the fourth
The irradiation position of the second harmonic ω2 can be moved around the harmonic ω4.

The second and fourth harmonics ω2°ω4 emitted in this way are reflected by the high reflection mirror 17 and enter the condensing optical system 5. This condensing optical system 5 is composed of a condensing lens 18 equipped with a high reflection mirror 17, and this condensing lens 18 is directed toward the processing surface of a substrate 6 as a workpiece held on a table 7, as will be described later. and the second harmonic ω, and the fourth harmonic
The harmonic wave ω41 is focused at a distance.

Further, the table 7 is housed in a reaction container 19, and can be driven in the X-Y direction as shown by arrow C. Note that here, the table 7 may be provided integrally with one reaction container, and the reaction container 19 may be moved in the X-Y direction.

The reaction vessel 19 is provided as an organometallic gas supply means, and a gas circulation device (not shown) is installed in the reaction vessel 19 so that an organometallic gas (metal carbonyl, alkyl aluminum) is supplied and discharged in the direction of arrow G. has
Further, a transmission window 20 is provided in the reaction vessel 19 facing the condensing lens 18 . Note that there are multiple types of metal carbonyls, such as tungsten carbonyl and molybdenum carbonyl.

A state in which a conductive film is directly drawn on the substrate 6 using the conductive film forming apparatus 1 configured as described above will be described with reference to FIGS. 3 and 4. FIG.

The substrate 6 shown in the figure is formed of, for example, 5to2, and on this substrate 6, for example, AI wirings 21 and 22 are formed. Then, the fourth harmonic wave ω4 is irradiated to the end of one of the wirings 21 in the organometallic gas, and then the second harmonic wave ω2 is irradiated in the opposite direction at a predetermined distance.

And each harmonic ω2. The substrate 6 is controlled to move in the direction of arrow R so that the irradiation position of ω4 moves in the direction of arrow F. At this time, the second and fourth harmonics ω2. ω4 moves relative to the substrate 6 at a constant interval, and the second
A state is reached in which the harmonic ω2 tracks the fourth harmonic ω4.

By being irradiated with this fourth harmonic ω4 (ultraviolet light), the organometallic gas is photodissociated and a nucleus is formed.

This nucleation process is carried out by the light separation of the organometallic gas adsorbed on the substrate, so 5i02. Nuclei can be stably formed across the surfaces of different metals such as AI. The decomposition of the organometallic gas is promoted on the surface of the substrate 6 on which nuclei are formed in this way, and the growth rate of the film in the film formation process described later is high and independent of the difference in the material of the substrate surface.

Then, the substrate 6 is locally heated by the irradiation of the second harmonic ω2 that follows the fourth harmonic ω4. That is, the second harmonic ω2 is irradiated to the portion where the nucleus is formed, and the organometallic gas is thermally decomposed, thereby growing the nucleus and depositing the metal film.

In this way, the conductive film 23 shown in the figure is formed.

As described above, by scanning the fourth harmonic ω4 first and controlling the second harmonic ω2 to follow it, it is possible to form a film at a higher speed than in the conventional laser CVD method, and also to 4 As shown in Figure 4, the substrate (SiO
□) 6 and the conductive film 2 over the wiring (AI) 21 and 22.
3 can be stably formed.

Note that the conductive film forming apparatus 1 needs to be adjusted by operating the prism support mechanism 16 so that the fourth harmonic ω4 is always located in the front with respect to the moving direction of the laser beam.

The present invention is not limited to the above embodiment. For example, the materials of the substrate 6 as a workpiece and the wirings 21 and 22 formed on the surface of the substrate 6 shown in the above embodiment are not equally limited.

〔Effect of the invention〕

(1) In the first step, the fourth
By irradiating harmonics, the organometallic gas is photodissociated to form a nucleus on the surface of the workpiece, and in a second step, the second harmonic that follows the fourth harmonic locally forms the nucleus. The film can be grown by heating, and the film formation process can be completed at a higher rate than conventional methods. Also, the fourth
Nuclei are formed by photodissociation by harmonics, and then a film is easily formed by heating by second harmonics, so stable films can be formed over two or more types of materials.

(2) By sequentially transmitting the laser light output from the YAG laser oscillation unit through the harmonic conversion unit and the prism,
It is possible to split the light into a harmonic and a fourth harmonic to produce two light beams. Then, the workpiece is irradiated with the second and fourth harmonics at a predetermined interval by passing through the condensing optical system in the organometallic gas, and the table on which the workpiece is placed is driven. A workpiece can be driven by the laser beam to form a film. Furthermore, by rotating the prism using the prism support mechanism, the fourth harmonic can be positioned in front of the second harmonic in the direction of film formation. With this configuration, the fourth
The process of forming a nucleus on the workpiece using harmonics and growing the nucleus using the second harmonic that follows this fourth harmonic to form a conductive film can be performed quickly and easily, resulting in stable quality. A conductive film can be formed.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a side view showing the schematic configuration of the conductive film forming apparatus and the laser beam irradiation state, FIG. 2 is a perspective view showing the shape of the image rotation prism and the spectral state of the laser light, FIG. 3 is a plan view of the substrate showing a state in which a conductive film is formed, and FIG. 4 is a side sectional view of the substrate after the conductive film is formed. DESCRIPTION OF SYMBOLS 1... Conductive film forming device, 2... Laser oscillation part, 3...
...Harmonic conversion unit, 4... Prism, 5... Condensing optical system, 7... Table, 19... Reaction vessel (organometallic gas supply means), ωl... Oscillation wavelength wave, ω2...
2nd harmonic, ω4...4th harmonic.

Claims (2)

[Claims] (1) YAG to the workpiece in an organometallic gas atmosphere
The first step is to irradiate the fourth harmonic of the laser to form a nucleus on the surface of the workpiece by photodissociation, and after this first step, the nucleation portion formed by the irradiation of the fourth harmonic is YAG
a second step of irradiating a second harmonic of a laser to grow a film on the nucleation portion. (2) A YAG laser oscillation unit, a harmonic conversion unit that converts the laser light output from the YAG laser oscillation unit into a composite light of second harmonics and fourth harmonics, and a prism that separates the synthesized light into a second harmonic and a fourth harmonic; a prism support mechanism that rotatably supports the prism with the axis of the laser beam as a rotation axis; a focusing optical system that focuses the second harmonic and the fourth harmonic on different locations on the surface of the workpiece; an organometallic gas supply means that supplies an organometallic gas to the surface of the workpiece; and a table that is driven and controlled in the X-Y direction so that the irradiation position of the second harmonic tracks the irradiation position of the fourth harmonic.