JP3319522B2 - Laser deposition system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser film forming apparatus for forming fine wiring on a semiconductor wafer by a laser CVD method, for example.

[0002]

2. Description of the Related Art In a wiring technique by a laser CVD method, a metal carbonyl is converted to Ar ⁺ A direct drawing method in which laser light is locally thermally decomposed is generally used. This method has the advantages that a high film quality is obtained, the stability of the source gas is high, and the window into which laser light is introduced is less contaminated.

[0003] The result of laser CVD film formation is significantly affected by the source gas supply method. There are two types of source gas supply methods: a decompression method for forming a film in a vacuum atmosphere, and a carrier gas method for forming a film under an atmospheric pressure environment. Since the above-mentioned decompression method requires a leaktight vacuum vessel, there are problems such as an increase in equipment cost and a reduction in throughput due to evacuation time. Since the above carrier gas method does not require a vacuum atmosphere, workability is good and practicality is high. In particular, in recent years, the size of electronic devices to which laser CVD is applied has been increased in size, and the carrier gas method has been widely used in terms of throughput and workability.

FIG. 2 shows a known apparatus for forming a film in the atmosphere using a carrier gas method. That is, 1 in the figure is an XY table. This X
A plate heater 2 is placed on the Y table 1, and a substrate 3 of a semiconductor wafer to be a film formation target is placed on the plate heater 2.

A nozzle body 4 is disposed above the substrate 3. A through hole 6 whose upper end is covered by a window 5 is formed in the nozzle body 4 so as to penetrate in the axial direction. One end is formed to communicate with the through hole 6.

The other end of the through hole 6 is connected to a reservoir 8 containing an organic metal 7 through a supply pipe 9. A mass flow controller 10 is connected to the reservoir 8, and the mass flow controller 10 communicates with a supply source of a carrier gas (not shown). The organic metal 7 in the reservoir 8 is heated and vaporized by the heater 11. As a result, the source gas in which the gaseous organic metal is mixed with the carrier gas is supplied to the supply hole 6a of the nozzle body 4 and flows out from the front end opening of the through hole 6.

A condensing optical system 12 is provided above the nozzle body 4.
The laser light L having a wavelength in the visible range and output from a laser oscillator 13 such as an argon laser is incident on the condensing optical system 12. The laser light L incident on the condensing optical system 12 is focused and passes through the window 5 through the through hole 6.
The substrate 3 placed on the plate heater 2 is irradiated through the plate heater 2. At this time, the source gas present at the portion irradiated with the laser light L is thermally decomposed, so that a metal film is locally formed on the substrate 3.

However, according to such a configuration,
Since a room temperature atmosphere exists around the portion of the substrate 3 irradiated with the laser light L, the source gas is cooled by the atmosphere, and the organic metal contained in the source gas is solidified.

The solidified organic metal becomes dust and contaminates the substrate 3 and causes new defects in a later process.
Since the dust has a weak adhesive force to the substrate 3, it can be removed by a cleaning process, but this poses a problem in a process in which cleaning cannot be performed after film formation.

In order to recover the unreacted source gas, a hood 21 is integrally provided on the nozzle body 4 as shown in FIG. So that the portion is hardly affected by the atmosphere, and an unreacted source gas is recovered by connecting an exhaust pipe 22 to the hood.

As described above, if the hood 21 is provided, the film formation site is hardly cooled by the air. However, the flow rate is such that the organic metal contained in the unreacted source gas flowing out of the nozzle body 4 does not reach the substrate 3.
When the interior of the source 21 is evacuated, the flow of the source gas in the film forming unit may be disturbed, and the film may not be formed.
When the inside of the hood 21 is evacuated at a flow rate at which the flow of the gas does not disturb, solidified organic metal adheres to the substrate 3.

[0012]

As described above, in the carrier gas method capable of forming a film in the atmosphere, the organic metal may be solidified and adhere to the object to be formed. Could not be prevented.

The present invention has been made in view of the above circumstances, and an object of the present invention is to discharge a gaseous organic metal without solidifying it onto a film-forming object without disturbing the flow of a source gas. An object of the present invention is to provide a laser film forming apparatus as described above.

[0014]

In order to solve the above-mentioned problems, the present invention provides a hood for covering an object to be formed and a source gas containing a gaseous organic metal inside the hood. Supply means; laser irradiation means for locally thermally decomposing the source gas supplied into the hood with visible laser light to form a metal film on the film-forming target; Discharge means for supplying the visible laser light and unreacted source gas which are supplied into the hood, and organic substances contained in the unreacted source gas provided on the hood and discharged by the discharge means. Heating means for preventing solidification of the metal.

[0015]

According to the above construction, the unreacted source gas flowing into the hood is heated by the heating means provided on the hood, so that the organic metal contained in the source gas is not heated. Excreted without coagulation.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. The same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof is omitted. That is, in the present invention, the substrate 3 is covered with the hood 21, similarly to the configuration shown in FIG. The outer surface of the hood 21, the supply pipe 9 for supplying the source gas to the nozzle body 4 and the exhaust pipe 22 for collecting the unreacted source gas are heated, for example, by embedding a heating element in a sheet-like resin. It is covered with heaters 21a, 9a and 22a and is heated to 50 to 200 ° C.

The exhaust pipe 2 having one end connected to the hood 21
The other end of 2 is connected to an exhaust trap 31. The inside of this exhaust trap 31 is vertically partitioned by a filter 32. The other end of the exhaust pipe 22 is connected to the filter 3
The lower space 2 is connected to the lower space, and the upper space is connected to the other end of the downstream exhaust pipe 34 having one end connected to the exhaust pump 33.

The exhaust trap 31 is provided with an electronic cooling element 35.
Is cooled below room temperature. Thereby, the organic metal contained in the unreacted source gas flowing into the exhaust trap 31 is solidified and recovered. As organic metals contained in the source gas, there are Ni carbonyl and Co carbonyl which are somewhat toxic, and these are discarded.
Expensive organometallics such as Pt carbonyl are recycled.

A flow control valve 36 is provided in the middle of the downstream exhaust pipe 34. The opening of the flow control valve 36 and the operation of the laser oscillator 13 are controlled by a control unit 37 in synchronization.

That is, when a start signal is input to the control unit 37, the laser oscillator 13 is operated after a predetermined time has passed since the input signal was input.
Until the laser oscillator 13 is operated, the flow control valve 36 is fully opened, and the inside of the hood 21 is purged by the source gas. When the laser oscillator 13 operates to form a film, the opening of the flow rate control valve 36 is reduced, and the source is exhausted.
The gas flow is prevented from being disturbed. The exhaust flow rate at this time is preferably about 5 to 20 LM. Then, when the laser oscillator 13 stops after the film formation is completed, the flow control valve 36 is fully opened, and the source gas remaining in the hood 21 is exhausted at once.

A procedure for forming a metal film by the laser film forming apparatus having the above configuration will be described. When a start signal for starting the film formation is input to the controller 37, the flow control valve 36 is fully opened and the hood 21 is purged by the source gas. Then, the opening degree of the flow control valve 37 is reduced, so that the source gas flows out of the nozzle body 4 without being disturbed, and the laser oscillator 13 operates to generate the laser light L. , Local thermal decomposition occurs continuously, and a metal film is formed on the substrate 3.

When the film formation is completed, the flow control valve 36 is fully opened to exhaust the source gas remaining in the hood 21 at a stretch. At this time, the hood 21, the supply pipe 9, and the exhaust pipe 2
2 are heated by the heating heaters 21a, 9a and 22a, respectively, so that the exhaust trap 31 passes therethrough.
The gaseous organic metal contained in the source gas flowing into the substrate 3 is prevented from solidifying and adhering to the substrate 3. That is, the organic metal contained in the source gas is reliably collected in the exhaust trap 31.

In the above-described embodiment, the heating heater is provided not only for the hood but also for the supply pipe and the exhaust pipe. However, the heating heater is not provided for the supply pipe and the exhaust pipe. In both cases, it is possible to prevent the organic metal from solidifying in the hood and adhering to the substrate.

The heating means is not limited to a sheet-shaped heater, and may be made of a metal which generates heat when the hood itself is energized, and the heating means is limited. Not.

[0025]

As described above, according to the present invention, an object to be film-formed is covered with a hood, a source gas is supplied into the hood, and the material is locally thermally decomposed by laser light. In the apparatus for forming a metal film on the object to be formed, a heating means is provided on the hood.

Therefore, the gaseous organic metal contained in the unreacted source gas remaining in the hood will not be cooled by the outside air and solidified before being discharged from the hood. In addition, it is possible to prevent the organic metal from becoming dust and adhering to the film formation target.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a laser film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional laser film forming apparatus.

FIG. 3 is a structural view showing a laser film forming apparatus having another conventional structure.

[Explanation of symbols]

8 reservoir (supply means), 10 mass flow controller (supply means), 13 laser oscillator (laser irradiation means), 21 hood, 21a heating heater (heating) Means), 22: exhaust pipe (exhaust means), 33: exhaust pump (exhaust means), 37: flow control valve (exhaust means).

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21/285

Claims (1)

(57) [Claims] 1. A hood for covering an object to be formed, a supply means for supplying a source gas containing a gaseous organic metal into the hood, and a source supplied to the inside of the hood. Laser irradiation means for locally thermally decomposing a laser gas with visible laser light to form a metal film on the object to be film-formed, and supplied to the hood and unreacted with the visible laser light And a heating means provided on the hood for preventing the organic metal contained in the unreacted source gas discharged by the discharge means from solidifying. A laser film forming apparatus.