JPH06349823A - Wiring formation - Google Patents

Abstract

PURPOSE:To form a local insulating film which has excellent mechanical strength on any substrate easily and safely without damaging the substrate and directly written wiring. CONSTITUTION:The surface of a silicon LSI substrate 1, which is provided with exposing wiring as shown in the Figure (a), is coated with a photosensitive polyimide film 2 as shown in the Figure (b) and the substrate is baked for approximately 10 minutes at 250 deg.C. Then, laser beams are swept over a part whereupon an insulating film is to be formed as shown in the Figure (c) so as to develop by developing liquid NMP and the polyimide film is left as shown in the Figure (d). Then, the polyimide film is transpired on wiring 3 and wiring 4, which need to be connected by laser abrasion, by a YAG laser second high frequency wave 6 and contact holes 7 and 8 are formed. Then, Ar laser 10 sweeps between the contact holes 7 and 8 in tungsten carbonyl as shown in the Figure (e) so as to form a directly written W wire 9 and the wiring is connected.

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 correction technique by a laser CVD direct drawing 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. Further, since it is excellent in operability and stability as a device, it is expected to be introduced into the production site of any LSI. However, if the board is modified at the stage where there is no insulating protective film on the top, it is necessary to form the direct drawing wiring across the existing wiring on the surface of the board, and the direct drawing wiring and the pipe of the existing wiring are insulated at the required locations. Is required.

As a means of forming an insulating film at a specific portion in this way, the local insulation technique by laser CVD is promising, according to Hiura et al., "Journal of Appl".
ied Physics, Sharnal of Applied Physics, Vol. 69, (3), p. 1744-
1747, (1991) ". This method is to form an insulating film locally by irradiating ArF excimer laser light to a desired insulating portion in an atmosphere of disilane and nitrous oxide gas that forms a silicon oxide film by a photochemical reaction by ultraviolet light. is there. This method requires an ArF excimer laser, which is expensive and has a high running cost, in addition to the visible light source used for laser CVD for direct drawing of wiring. In addition, disilane gas is a highly dangerous gas that spontaneously ignites in the air, so care must be taken when handling it.

A method for forming a dielectric film by 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 is known as "Journal". of Vacuum Sci
ence And Technology (Journal of Vacuume Science and Technology), B2, (4), pages 641-644, 1984.
(October-December) "by Osgood (Osgood) et al., And there is a possibility that a local insulating film can be formed easily and safely by this method. However, since the liquid coating material for forming the dielectric film is transparent to visible light, there is a problem that the film cannot be formed when the substrate has a high thermal conductivity or a transparent substrate.

A solution of a raw material for forming an insulating film, which is thinned by heating, is applied to the surface of a substrate, the solvent is removed and solidified, and a metal film is directly drawn on the metal film by a light heating action at that time. A method of thinning the lower insulating film forming raw material and then etching away the raw material in the portion not irradiated with the laser beam by using this direct drawing line as a mask is described in “3.
Proceedings of the 8th Joint Lecture Meeting of the Japan Society of Applied Physics, page 565 ",
It is reported in "The 39th Federation of Applied Physics Federation Proceedings 568". Using this method, an insulating film can be formed regardless of the type of substrate. However, such a method may cause a problem of mechanical strength deterioration such as peeling of the insulating film and the directly drawn wiring portion at the etching stage.

[0006]

As described above, according to the conventional method, it is difficult to add the function of locally forming the insulating film excellent in mechanical strength without being limited to the kind of the substrate.

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

[0008]

The wiring forming method of the present invention is characterized in that the laser light is focused on the surface of a substrate placed in an atmosphere of a raw material gas for depositing a conductive material by a thermal decomposition reaction, In a wiring forming method of drawing wiring by scanning relative to a substrate, an insulating resist thin film is formed on the substrate before drawing, and an insulating desired portion of the resist thin film is exposed and patterned by development. After the remaining, the resist thin film on the wiring to be connected is evaporated by laser irradiation, and then the wiring is drawn.

Further, while the laser light is focused on the surface of the substrate placed in the atmosphere of the raw material gas for depositing the conductive substance by the thermal decomposition reaction, the wiring is drawn by relatively scanning the substrate. In the wiring forming method, an insulative resist thin film is formed on the substrate before drawing, and a desired insulating portion of the resist thin film except for the upper portion of the wiring to be connected is exposed, patterned after development, and then the wiring is drawn. It is characterized by

[0010]

The resist used in the semiconductor process can be freely patterned by coating, exposing, and developing. If a resist having a sufficiently high volume resistivity is used, it is possible to use a patterned resist thin film as an insulating film. The heat resistant temperature varies depending on the resist, but it usually solidifies at about 250 ° C and becomes stable.
No damage occurs even if the metal is directly laser-drawn.

The present invention utilizes the properties of such a resist to apply a laser beam having a wavelength at which an insulative resist is coated on a substrate such as an LSI which requires local formation of an insulating film on the surface and the resist is exposed to light. Is swept into a desired shape larger than the wiring width, and an insulating film is locally formed by developing, and a contact hole is formed on the wiring requiring wiring by laser ablation. The existing wirings are connected by forming the wirings between the contact holes by laser direct drawing.

Further, the present invention utilizes the properties of the resist such as heat resistance and insulating property to apply the insulating resist onto a substrate such as LSI which requires local formation of an insulating film on the surface, A laser beam of a wavelength that sensitizes this is swept into a desired shape larger than the wiring width in a shape excluding the contact hole portion on the wiring that requires connection, and the insulating film is locally formed by developing, and a metal film is formed. The existing wiring is connected by forming the wiring between the contact holes by direct drawing with a laser in a forming material gas atmosphere.

In the present invention, since the applied film itself is exposed to light, it can be formed regardless of the type of substrate. Further, since it is performed through patterning exposure and development, the mechanical strength of the insulating film is not impaired as in the case where etching using the direct drawing wiring as a mask is required.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the method according to the present invention is applied to a wiring modification that requires wirings on both sides of the wiring over exposed wirings will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing the method of the present invention.
First, as shown in (b), a photosensitive polyimide film 2 is formed on the surface of an LSI substrate 1 having exposed wiring shown in (a).
After forming by coating, it was baked at 250 ° C. for about 10 minutes. Next, as shown in (c), the emitted light of the Ar laser light 10 was swept to the insulating film forming portion, and developed with a developing solution NMP to leave a polyimide film as shown in (d). Next, the polyimide films on the wirings 3 and 4 which require connection were evaporated by laser ablation using a YAG laser second harmonic wave 6, which is a pulse laser, to form contact holes 7 and contact holes 8.

Subsequently, as shown in (e), contact holes 7 and 8 are formed in tungsten carbonyl.
The direct drawing W line 9 was formed by sweeping the Ar laser 10 between them, and the wirings were connected. The deposition resistance between the direct drawing W line 9 insulated by the photosensitive polyimide film 2 and the wiring 5 was 1 × 10 ¹⁶ Ω · cm, which was sufficiently large.
Moreover, since the temperature rise during direct writing was at most 150 ° C., the polyimide film was not damaged. Further, in the present invention, the insulating film and the directly drawn portion were not peeled off after long-term use, and a local insulating portion having sufficient mechanical strength could be obtained.

Further, as another embodiment of the present invention, as shown in (c) after sweeping the Ar laser 10 into a shape excluding the contact holes 11 and 12 as shown in (f) following (b) as another embodiment. Even if it was developed and the direct drawing W wiring 9 was formed as shown in (e), a good local insulating portion having the same characteristics could be obtained.

In the present invention, since the visible laser light is used for forming the thin film, the light source and the optical system used for direct drawing of the ordinary wiring can be used as they are, and the operability is improved even when the wiring is continuously corrected. It is not damaged. In addition, since no dangerous raw material gas is used, safety in work is not impaired. Moreover, since the applied film itself is exposed to light, it can be formed regardless of the type of substrate. Further, since the patterning is performed through exposure and development, etching for masking the direct drawing wiring is not necessary and the mechanical strength of the insulating film is not impaired.

In the present invention, the resist is not necessarily limited to the photosensitive polyimide, and is not limited to 200.
Any resist may be used as long as it has a heat resistance of about ℃ and is exposed to a light source used for direct drawing. For example, AZ resist, PFI-15A, etc. can also be used.

[0020]

As described above, according to the method of the present invention, it is possible to easily and safely form an insulating film having excellent mechanical strength on any substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Silicon LSI Substrate 2 Photosensitive Polyimide Film 3 Wiring 4 Wiring 5 Wiring 6 YAG Laser Second Harmonic Wave 7 Contact Hole 8 Contact Hole 9 Direct Drawing W Line 10 Ar Laser 11 Contact Hole 12 Contact Hole

Claims (2)

[Claims] 1. A wiring is provided on a surface of a substrate placed in an atmosphere of a raw material gas that deposits a conductive substance by a thermal decomposition reaction while scanning laser light while relatively focusing the laser light on the substrate. In the wiring forming method before drawing, an insulating resist thin film is formed on the substrate before drawing, and an insulating desired portion of the resist thin film is exposed, and after patterning is left by development, the upper part of the wiring to be connected is formed. A method for forming a wiring, wherein the resist thin film is evaporated by laser irradiation and then a wiring is drawn. 2. 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 scanning is performed relative to the substrate to form a wiring. In the wiring forming method for drawing, an insulating resist thin film is formed on the substrate before drawing, and an insulating desired portion of the resist thin film except the upper portion of the wiring to be connected is exposed,
A wiring forming method, which comprises patterning by development and then drawing wiring.