JP3136624B2 - Film 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 film forming method.

[0002]

2. Description of the Related Art A wiring repair technique based on a laser CVD direct writing wiring forming method can be applied to a multilayer wiring structure substrate such as an LSI, and greatly contributes to applications such as shortening the development period of the LSI. In addition, since it is excellent in operability and safety as an apparatus, introduction of all LSIs to a production site is expected. However, when the substrate is modified at the stage where there is no insulating protective film on the top, it is necessary to form a direct drawing wiring across the existing wiring on the substrate surface, and it is required to insulate both wirings at required places . Proposal of a promising local insulating technique by laser CVD as a means for forming an insulating film at a specific portion in this way is proposed in a paper by Hiura et al. This method forms a silicon oxide film by a photochemical reaction by ultraviolet light. In an atmosphere of disilane and nitrous oxide gas, a portion where local insulation is desired is irradiated with an ArF excimer laser to locally form an insulating film. Is what you do. In this method, apart from a visible light source used for laser CVD for direct wiring drawing, an expensive and high running cost Ar
Since an F excimer laser is required, the apparatus is large and complicated, and there is a drawback that it is inferior in practical use. Since disilane gas is a highly dangerous gas such as spontaneously ignited in the air, it must be handled with care.

A method of spin-coating a liquid coating material for forming a dielectric film on a substrate and locally heating the substrate by irradiation with a visible light laser to form a dielectric film is disclosed in Journal of Science Technology B2 ( 4), reported by Osgood et al. In 1984 (October-December), it is possible to form a local insulating film simply and safely by this method. However, since the liquid coating material for forming a dielectric film is transparent to visible light, there is a problem that the film cannot be formed when the thermal conductivity of the substrate is high or when the substrate is transparent.

[0004]

As described above, in the conventional method, the wiring correction apparatus for depositing the conductive thin film by the direct laser CVD is not greatly changed, and the safety is not impaired. It is difficult to add a function of forming an insulating film locally without being performed.

An object of the present invention is to provide a film forming method which solves such problems of the conventional method.

[0006]

According to the film forming method of the present invention, a solution of a raw material for forming an insulating film, which is formed into an insulating film by heating, is applied to the surface of the substrate, the solvent is removed, and then the conductive thin film is formed by heating. In the source gas atmosphere to be formed, the substrate is irradiated with laser light having a wavelength that is absorbed by the conductive thin film to form a conductive thin film, and at the same time, the substrate is heated by heat conduction from the heated conductive thin film. A layer of a raw material for forming an insulating film between the surface of the substrate and the conductive thin film is formed into an insulating film.

Further, according to the present invention, it is preferable that a part of the insulating film forming material not irradiated with the laser beam is removed by etching using the conductive thin film as a mask.

[0008]

When a laser beam is condensed and radiated onto a substrate in an atmosphere of a CVD source gas, the temperature of the irradiated portion rises, and deposition occurs only in the irradiated portion. At the same time, heat is transmitted to the substrate below the deposited film by heat conduction, thereby increasing the temperature of the substrate. On the other hand, a solution of a raw material for forming an insulating film which is turned into an insulating film by heating is applied to the substrate,
There is known a method of forming an insulating film by heating after drying and removing a solvent. In this case, the raw material for forming the insulating film on the substrate before heating is easily removed with dilute hydrofluoric acid or the like, whereas the heated portion has an extremely low etching rate. The present invention takes advantage of these facts by applying a raw material for forming an insulating film to a substrate, and then condensing the laser light on the substrate in a raw material gas atmosphere for forming a conductive thin film opaque to the laser light. At the same time as forming the conductive thin film pattern, and at the same time, locally insulating between the substrate surface before the application and the conductive thin film pattern as required. Further, according to the present invention, when it is necessary to remove the raw material for forming the insulating film other than the necessary portion, the conductive thin film pattern is used as a mask to remove by etching.

In the present invention, since a visible light laser is used for forming a thin film, a light source and an optical system used for normal wiring direct drawing can be used as they are, and operability can be improved even when wiring correction is performed continuously. There is no loss. In addition, the safety in operation is not impaired because dangerous raw gas is not used. Further, since the applied film itself is indirectly heated by heat conduction from the upper conductive thin film, the insulating film can be formed regardless of the type of the substrate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the method according to the present invention is applied to a wiring correction which requires connecting wirings on both sides beyond a wiring exposed on a substrate will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram illustrating the method of the present invention.
First, OCD (Si-20000-SG manufactured by Tokyo Ohka) is applied to the surface of the silicon LSI substrate 6 having the exposed wiring, and the solvent is dried to form a film of the silicon oxide film forming raw material 5. 6 is fixed to the XY stage 7 in the growth chamber 11. The emitted light of the Ar laser 1 passes through the half mirror 2, the lens 3, and the window 4, and the silicon LS
Irradiation is performed on the I substrate 6. The silicon LSI substrate 6 can be moved in a horizontal plane by an XY stage 7 in the growth chamber 11 by an external control signal. The vicinity of the laser beam irradiating section is illuminated with reflected light from the illumination half mirror 9 of the illumination light source 8, and an image is formed by an optical system including the lens 3, the half mirror 2, and the eyepiece 10 to observe the irradiating section. It can be configured.

In the growth chamber 11, a source gas W (C
O) ₆ is flowed and Ar
After the silicon LSI substrate 6 is moved by the XY stage 7 while observing with the eyepiece 10 so that the laser 1 is irradiated, the irradiated portion is heated by irradiating the Ar laser 1 to form the W film and simultaneously the W film is formed. The raw material 5 for forming a silicon oxide film under the film was heated and reformed into a silicon oxide film. Next, the silicon LSI substrate 6 is washed with low-concentration hydrofluoric acid to remove the silicon oxide film forming raw material 5 except for the irradiated portion by etching, and to locally remove silicon oxide between the underlying wiring and the deposited W. A film could be formed.

In the present invention, since a visible light laser having excellent stability and long life is used, local insulating work can be performed efficiently. In addition, since the visible light laser used for wiring correction by direct metal drawing is used, local insulation can be performed simultaneously with direct wiring drawing in the same apparatus as the direct metal drawing apparatus. Further, the present invention does not use highly dangerous raw material gas, so that the operation can be performed safely. Further, in the present invention, since the insulating film forming raw material is heated by heat conduction to form an insulating film, the film can be formed regardless of the thermal conductivity of the substrate and the visible light absorption. In the present invention, hydrofluoric acid cleaning is not required if the device characteristics are not affected even if the coating film in the portion not irradiated with the laser beam remains. It is not always necessary to use an Ar laser as the visible light laser. Copper vapor laser, YAG laser, He without departing from the spirit of the present invention
A -Cd laser, a Kr laser, a visible light semiconductor laser, or the like can also be used.

OCD (Si-20000-S manufactured by Tokyo Ohka Co., Ltd.) is not necessarily used as a coating solution of a raw material for forming a silicon oxide film.
It is not necessary to use G). Either an OCD without addition of an impurity or an OCD with a low impurity concentration can be used. Further, products other than Tokyo Ohka, such as Nippon Soda's Atron, can be used as long as they do not depart from the gist of the present invention. It is not necessary to use W as a thin film material. Au, Al, etc., which do not depart from the spirit of the present invention, can also be used.

[0015]

As described above, according to the method of the present invention, an insulating thin film having good surface morphology can be easily and safely formed locally on any substrate.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment to which the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 Ar laser 2 Half mirror 3 Lens 4 Window 5 Raw material for forming silicon oxide film 6 Silicon LSI substrate 7 XY stage 8 Illumination light source 9 Illumination half mirror 10 Eyepiece 11 Growth chamber

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/3205 H01L 21/321 H01L 21/3213 H01L 21/768 H01L 21/28-21/288 H01L 21/44-21 / 445 H01L 29/40-29/51 H01L 29/872 H01L 21/314-21/318 H01L 21/471-21/473

Claims (2)

(57) [Claims] A solution of a raw material for forming an insulating film, which is formed into an insulating film by heating, is applied to the surface of the substrate, and after removing the solvent, the solution is heated on a substrate in a raw material gas atmosphere for forming a conductive thin film by heating. At the same time as forming the conductive thin film by irradiating the conductive thin film with a laser beam having a wavelength absorbed by the conductive thin film, the surface of the substrate and the conductive thin film are heated by heat conduction from the heated conductive thin film. Forming a layer of the raw material for forming an insulating film into an insulating film. 2. The film forming method according to claim 1, wherein the insulating film-forming material in a portion not irradiated with the laser beam is removed by etching using the conductive thin film as a mask.