JP2712916B2 - 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 wiring forming method.

[0002]

2. Description of the Related Art A wiring repair technique using a laser CVD direct writing formation 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 stability as an apparatus, introduction of any LSI to a production site is expected. However, when modifying the board 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 board surface, and it is required to insulate both wirings at required places . Hiura et al. Reported that the promising local insulating technique by laser CVD as a means for forming an insulating film at a specific location is described in the Journal of
Applied Physics, vol. 69, (3), page 17
44-1747, (1991) ". This method forms a silicon oxide film by a photochemical reaction using ultraviolet light, and forms an insulating film locally by irradiating an ArF excimer laser to an area where local insulation is desired in an atmosphere of disilane and nitrous oxide gas. Is what you do. This method requires an expensive and high running cost ArF excimer laser separately from a visible light source used for laser CVD for direct wiring drawing, so that the apparatus is large-scale and complicated, resulting in poor practicality. Since disilane gas is a highly dangerous gas such as spontaneously ignited in the air, care must be taken when handling it.

A method of spin-coating a liquid coating material for forming a dielectric film on a substrate that absorbs visible light and locally heating the substrate by irradiation with a visible light laser to form a dielectric film is disclosed in "Journal. ObScience Technology, B
2, (4), pp. 641-644, 1984, (October-December) "by Osgood et al. There is a possibility that a local insulating film can be easily and safely formed 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] A solution of a raw material for forming an insulating film, which is converted into an insulating film by heating, is applied to the surface of the substrate, and the solvent is removed and solidified.
The metal film is directly drawn with a laser on it, and the lower part is made into an insulating film by the light heating action at that time. Then, using the drawn line as a mask, the material for forming the insulating film that is not irradiated with the laser light is etched. According to Seki et al., "The 38th Annual Meeting of the Japan Society of Applied Physics, 565 pages"
Has been reported to. By using this method, an insulating film can be formed irrespective of the type of substrate, but the difference in etching rate between the underlying wiring and the applied insulating film is generally reduced by a simple wet etching method. Prone to damage.

[0005]

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 causing damage to the surface of the substrate. An object of the present invention is to provide a film forming method which solves the problems of the conventional method.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides a method of forming a laser beam on a surface of a substrate installed in an atmosphere of a source gas for depositing a conductive substance by a thermal decomposition reaction. A step of sequentially applying a calixarene thin film and an insulating film to be turned into an insulating film by heating on the substrate before drawing in a wiring forming method for drawing a wiring by scanning relatively to the substrate while condensing light. Then, a means was added to wash the substrate after drawing the wiring and leave only the insulating film under the drawn wiring. Further, the present invention provides the above calixarenes as 5, 11, 17, 2
3, 29, 35, hexamethyl 37, 38, 39, 4
0, 41, 42 hexaacetoxycalix [6] arene.

[0007]

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, the solution of the insulating film-forming material to SiO ₂ form a film applied to the substrate by heating, heating after the solvent removed by drying, but a technique for forming the SiO ₂ film are known, thereby forming The technique of using simple wet etching cannot remove the SiO ₂ film except for using hydrofluoric acid. Therefore, if the underlying wiring is made of a material having a high reactivity with hydrofluoric acid such as Al, there is a high risk of damaging the material. On the other hand, calixarene forms a thin film having an insulating property only by being applied, and can be easily removed by an organic solvent such as ethyl alcohol, but has the property of not being dissolved in an acid solution such as hydrofluoric acid. However, since the heat resistance is lower than that of the SiO ₂ film, damage is easily caused by heating during laser CVD, and it is necessary to precisely control laser CVD conditions such as laser irradiation intensity. According to the present invention, the calixarene thin film is a two-layer insulating film in which an SiO ₂ film formed by a coating liquid for forming an insulating film is formed on the lower side in contact with the substrate surface. By sequentially performing etching with an organic solvent in the vicinity of the surface, the insulating film other than the required insulating portion can be removed by etching without causing damage to the surface.

A more specific process procedure is to apply a calixarene to a substrate, apply a coating liquid for forming an insulating film to the substrate, and apply laser light focused in a source gas atmosphere for forming a conductive thin film. At the same time that the conductive thin film pattern is formed by scanning on the substrate, the surface of the substrate and the conductive thin film pattern are locally insulated. The calixarene used has a heat resistance of about 400 ° C. and a high solubility in many organic solvents 5, 11, 17, 23, 29, 3
5, hexamethyl 37, 38, 39, 40, 41, 42
Hexaacetoxy calix [6] arene, which is easier to etch than using other types of calix arenes. The coating film other than the insulating film is removed by etching the upper layer with hydrofluoric acid and the lower layer with an organic solvent using the conductive thin film pattern formed by direct lace as a mask.

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 direct wiring drawing can be used as they are, and operability is improved even when wiring correction is continuously performed. 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. Further, when etching the insulating film other than the necessary portion, the lower layer portion in contact with the surface is etched with an organic solvent, so that there is no danger of causing damage to the substrate surface.

[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 of a wiring exposed over a substrate will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram illustrating the method of the present invention.
First, a calixarene-based thin film 13 is formed on the surface of a silicon LSI substrate 6 having an exposed wiring by coating, and then OCD (Si-20000-SG manufactured by Tokyo Ohka) is coated, and the solvent is dried to form a silicon oxide film. After forming the film of the raw material 5, the silicon LSI substrate 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,
The light is applied to the SI substrate 6. Silicon LSI substrate 6 is XY
The stage 7 enables movement in the horizontal plane in the growth chamber 11 by an external control signal. The vicinity of the laser beam irradiating section is illuminated with the 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.
A source gas W (CO) ₆ 12 for forming a W film is passed through the growth chamber 11, and an Ar laser 1 is applied to a portion where a silicon oxide film needs to be formed.
X while observing with the eyepiece 10 so that
After the silicon LSI substrate 6 is moved by the Y stage 7, the irradiated portion is heated by irradiating the Ar laser 1 to form the W film, and at the same time, the silicon oxide film forming material under the W film is heated to form the silicon oxide film. Was modified. Next, the silicon LSI substrate 6 is first washed with low-concentration hydrofluoric acid and then with alcohol to remove the silicon oxide film-forming material other than the irradiated portions by etching, thereby forming a space between the underlying wiring and the deposited W. A silicon oxide film could be formed locally.

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, since the present invention does not use a highly dangerous raw material gas, the correcting operation can be performed safely. 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, when etching the insulating film other than the necessary portion, the lower layer portion in contact with the substrate surface is etched with an organic solvent, so there is no danger of causing damage to the substrate surface. As a visible light laser, A
There is no need to use an r-laser. Copper vapor laser, YAG laser, He-Cd laser, Kr without departing from the spirit of the present invention
A laser, a visible light semiconductor laser, or the like can also be used.

The coating liquid of the raw material for forming a silicon oxide film is not necessarily OCD (Si-210000 manufactured by Tokyo Ohka).
-SG) need not be used. OC without impurity addition
D or any OCD having a low impurity concentration can be used. In addition, a coating liquid that does not deviate from the gist of the present invention can be used for products other than Tokyo Ohka, such as the Atron of the Japanese layer company. It is not always necessary to use W as the conductive thin film material. Au, Al, etc., which do not depart from the spirit of the present invention, can also be used.

[0014]

As described above, according to the method of the present invention, it is possible to easily, safely, undamaged and locally form a good insulating thin film 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 silicon oxide film formation 6 Silicon LSI substrate 7 XY stage 8 Illumination light source 9 Illumination half mirror 10 Eyepiece 11 Growth chamber 12 W (CO) ₆ 13 Calixarene

Claims (2)

(57) [Claims] 1. A laser beam is focused on a surface of a substrate placed in an atmosphere of a raw material gas for depositing a conductive substance by a thermal decomposition reaction, and wiring is drawn by scanning relative to the substrate. In the wiring forming method, a step of sequentially applying a calixarene thin film and an insulating film to be turned into an insulating film by heating on the substrate before drawing, further washing the substrate after drawing the wiring, and only the insulating film under the drawn wiring. A wiring forming method, comprising the step of leaving 2. The wiring forming method according to claim 1, wherein the calix arenes are 5, 11, 17, 23, 29, 3
5, hexamethyl 37, 38, 39, 40, 41, 42
Hekisaa cell Toki wiring forming method is a deer helix [6] arene.