JP2985294B2 - Wiring formation 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 method for forming a wiring constituting an integrated circuit or the like.

[0002]

2. Description of the Related Art Conventionally, as a wiring forming method, there are a method using photolithography, a direct drawing method using a laser vapor deposition method, and the like. Regarding the latter, see, for example, G. FIG. Bl
Applied Physics Letters 1 by ack et al.
A method of directly drawing W has been reported in Vol.

[0003]

The above-described method using the conventional photolithography requires six steps of film formation, resist coating, exposure, development, etching, and resist removal in addition to the preparation of a photomask. There are disadvantages that are expensive. Further, in the laser direct writing method by the vapor phase growth method, in order to form a wiring having a desired film thickness, the drawing speed is limited low due to the supply of the raw material in the gas phase, so that a high throughput cannot be obtained. There are drawbacks.

[0004]

According to the present invention, there is provided a method for forming a wiring on a substrate having an insulating film on the surface, comprising the steps of: depositing a silicon thin film on the entire surface of the substrate and terminating the surface with hydrogen. A step of scanning the substrate relative to the laser beam while irradiating the substrate with the laser beam condensed on the above-described process to remove hydrogen termination into a desired pattern shape; The method is characterized by comprising a step of selectively growing a wiring material in the pattern shape by a method, and a step of finally forming a silicon thin film into an insulating film or removing it by etching. In the above-described wiring forming method, dimethylaluminum hydride or an intermolecular compound of trimethylaluminum and dimethylaluminum hydride is used as a source gas for growing a wiring material.

[0005]

For example, when aluminum is formed by selective chemical vapor deposition using dimethylaluminum hydride, aluminum is deposited on silicon and aluminum is not deposited on a silicon oxide film, so that selectivity is obtained. Is the 50th Annual Meeting of the Japan Society of Applied Physics Proceedings 63
There is a report by Niizawa et al. In 1-page lecture number 29p-D-1. In the selective growth process using dimethylaluminum hydride, the substrate temperature was 210 ° C. to 230 ° C. between the case where the surface of the silicon thin film was hydrogen-terminated and the case where the clean surface of silicon was exposed without hydrogen termination. A new phenomenon was found that aluminum grows on a substrate without hydrogen termination, whereas aluminum does not grow on a substrate with hydrogen termination. Furthermore, after scanning while irradiating the laser beam condensed on the hydrogen-terminated substrate, a pattern is formed by desorbing hydrogen in the laser beam irradiating portion, and the above-mentioned selective growth of aluminum is performed, hydrogen is removed. It was found that it was possible to form a pattern of aluminum with good reproducibility on the desorbed portion. After the growth of aluminum, the silicon thin film for pattern formation is turned into an insulating film by a technique such as oxidation or removed by etching. In this way, an arbitrary wiring pattern can be formed on the substrate.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a substrate formed by a main process according to one embodiment of the present invention. This embodiment is a case where the present invention is applied to formation of a wiring in a silicon integrated circuit.

FIG. 1A shows a structure after a polycrystalline silicon film, which is the first step, is formed on a substrate formed using a standard integrated circuit manufacturing method. The substrate 1 includes silicon 2 including an element region and an insulating film 3 made of an SiN film serving as an interlayer insulating film. The polycrystalline silicon thin film 4 only needs to have a thickness enough to cover the entire surface of the substrate. In this embodiment,
A polycrystalline silicon film 4 having a thickness of 100 Å is deposited by a sputtering method. Immediately after the deposition of the polycrystalline silicon thin film 4, a hydrogen plasma is generated in the same chamber, and the substrate 1 is exposed to the hydrogen plasma to hydrogen terminate the surface of the polycrystalline silicon thin film 4. Next, the substrate 1 is moved to a chamber where the focused laser beam 5 can be irradiated in a vacuum. The laser light source is an argon ion laser and the substrate 1
The upper beam diameter is 1 μm, and the scanning speed of the substrate is 10 cm /
s, and the irradiation intensity was 40 mW. As shown in FIG. 1B, the laser beam 5 is scanned to locally heat the polycrystalline silicon thin film 4 in the portion irradiated with the laser beam 5 to desorb hydrogen. Next, thermal CVD of dimethyl aluminum hydride
The substrate 1 was moved to a chamber for performing the above without exposing the substrate 1 to the atmosphere, and aluminum was selectively grown at a substrate temperature of 215 ° C. The growth conditions for the aluminum wiring are a carrier hydrogen flow rate of 60 sccm, a chamber total pressure of 2 Torr, and a dimethyl aluminum hydride partial pressure of 0.5 Torr. Through this step, as shown in FIG. 1C, the aluminum wiring 6 is selectively grown. Finally, the polycrystalline silicon film 4 other than the aluminum wiring portion is exposed to oxygen plasma at a substrate temperature of 300 ° C. to oxidize (change the polycrystalline silicon film 4 into silicon dioxide 7) as shown in FIG.
By doing so, all the steps are completed.

The time required for forming the wiring is the sum of the time required for each step, but the processes in FIGS. 1A and 1D are each completed in about 5 minutes because the thickness of the film to be processed is small. . Further, in the process of FIG. 1B, in the case of standard gate array wiring, it takes about 5 minutes per chip. In the step of FIG. 1C, the deposition rate of the aluminum film is
Since the process is performed collectively over the entire surface of the substrate at a high speed of about 4000 Å / s, the process can be completed in about two minutes per substrate. From these facts, compared with the case where the wiring is formed by the laser vapor deposition method, the processing time is 10 times even when forming about several chips.
In the case of producing chips of less than 1/0, especially tens to hundreds of chips, a much higher throughput can be obtained. Also, compared to the case where a normal photolithography process is used, the number of processes is as small as about four processes, and each process can be configured by a continuous dry process. It has an unprecedented advantage as a small-quantity multi-product manufacturing process.

In this embodiment, dimethyl aluminum hydride was used as a wiring material. However, similar selective growth was observed when dimethyl aluminum hydride and an intermolecular compound of trimethyl aluminum were used. In consideration of the above, similar selective growth is possible with other organic aluminum raw materials such as trimethylaminealane or a mixed raw material of another organic metal raw material and an organic aluminum raw material.

It is needless to say that other visible and ultraviolet laser light sources can be used for patterning by thermal desorption of hydrogen or photochemical desorption. In the treatment of the silicon thin film in the last step, a means such as nitridation or etching removal other than oxidation can be selected according to the application.

In addition to the polycrystalline silicon thin film, a hydrogenated amorphous silicon thin film which is considered to have no significant difference in the bond structure on the surface can be applied to the hydrogen-terminated silicon thin film. The substrate to which the present invention can be applied is not limited to the silicon integrated circuit described in the embodiment, but is also applicable to a high-density mounting wiring substrate between integrated circuit chips, wiring of a flat display device, and the like. In such applications,
Since the total wiring length is long, it is effective to simultaneously irradiate a plurality of laser beams in the step of directly drawing a laser beam to shorten the drawing time.

[0012]

As described above, according to the present invention, the number of steps and the number of operations can be significantly reduced, and wiring can be formed with high throughput. There is an advantage that it can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a silicon integrated circuit showing main steps of one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 silicon 3 insulating film 4 polycrystalline silicon 5 laser beam 6 aluminum wiring 7 silicon oxide

Continuation of the front page (72) Inventor Iwao Nishiyama 5-7-1 Shiba, Minato-ku, Tokyo Inside the NEC Corporation (72) Inventor Tsutomu Niizawa 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation In-house (56) References JP-A-4-37121 (JP, A) JP-A-2-178930 (JP, A) JP-A-3-183769 (JP, A) JP-A-3-141635 (JP, A) JP-A-4-37133 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/28-21/288 H01L 21/44-21/445 H01L 29/40-29 / 51 H01L 29/872 H01L 21/3205 H01L 21/321 H01L 21/3213 H01L 21/768

Claims (2)

(57) [Claims] In a method for forming a wiring on a substrate having an insulating film on the surface, a step of depositing a silicon thin film on the entire surface of the substrate and terminating the surface with hydrogen, and condensing the light on the substrate having been subjected to the step A step of scanning the substrate relative to the laser beam while irradiating the laser beam to remove hydrogen termination into a desired pattern shape, and thereafter, selectively growing a wiring material in the pattern shape by a vapor phase growth method And forming a silicon thin film as an insulating film or removing the silicon thin film by etching. 2. The wiring forming method according to claim 1, wherein dimethyl aluminum hydride or an intermolecular compound of trimethyl aluminum and dimethyl aluminum hydride is used as a source gas for growing a wiring material.