JP2533510B2 - Wiring formation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for additionally forming a wiring film on a sample, and particularly to a wiring forming method suitable for additionally connecting a wiring to an exposed conductor. .

[Conventional technology]

When developing a semiconductor device, a wiring error or the like usually occurs due to various factors. Therefore, the semiconductor development process includes inspection, defect analysis, and wiring correction processes.
Since shortening the debugging process directly leads to shortening the development period of the semiconductor device, many debugging means are currently being studied. As one method among them, as shown in FIG. 4, the wiring of the semiconductor device is cut by the focused ion beam, the wiring is added to the surface of the semiconductor device and the wiring layer is exposed by the focused ion beam. Among them, a method that combines a method of forming wiring by irradiating an energy beam such as an ion beam, an electron beam, or a laser beam and performing CVD is effective. As a method of forming this wiring, there are Extended Abstracts of the Seventeenth Conference on Solid Stud Devices and Materials (19
1985, pages 193 to 196 (Extended Abstracts of th
e 17th.Conference on Solid State Devices and Mater
ials, Tokyo 1985.p.193-196), etc., and laser CVD, which is being discussed at present, is excellent in terms of wiring formation speed and wiring resistance, so research is actively conducted. However, according to the experiments by the inventors, the following problems have been clarified when a window is opened in the wiring layer by an ion beam and a CVD film is deposited by laser irradiation. In other words, usually aluminum is used for wiring, but aluminum has a high light reflectance and absorbs only 10% of laser energy. Therefore CV
The laser energy must be increased to deposit the D film.

On the other hand, the absorption rate of the CVD film is about 50%, and the laser energy absorbed at the same time as the deposition of the CVD film increases five times at a time, so the temperature of the laser irradiation part rises sharply, and aluminum bumps, etc. Damage occurs. Therefore, it was necessary to develop a method for depositing a CVD film with a low energy laser beam.

[Problems to be solved by the invention]

In the above-mentioned prior art, no consideration is given to the above-mentioned damage caused by the difference between the reflectance of the wiring in the semiconductor device and the reflectance of the CVD film, and it is difficult to actually pull out the wiring from the inside of the semiconductor device.

An object of the present invention is to provide a wiring forming method for depositing a CVD film with a low energy laser beam which does not cause the above damage.

[Means for solving problems]

In order to achieve the above object, in the present invention, an insulating film is irradiated with an ion beam to expose a conductor, and the exposed surface of the conductor is irradiated with an ion beam under different irradiation conditions to reduce the reflectance of the surface. Then, a method of forming a wiring film by irradiating a laser beam on the surface of the conductor whose reflectance has been reduced in a CVD gas atmosphere is adopted.

[Operation] A window is formed in the wiring in the semiconductor device by ion beam processing to expose the wiring surface such as aluminum. Then, the deflection signal of the ion beam is switched from the beam scanning state up to the opening of the window to a deflection signal for forming unevenness on the wiring surface to reduce the light reflectance on the wiring surface, and the wiring surface is processed. Next, the exposed portion of the wiring is irradiated with a laser beam in a CVD gas atmosphere. At this time, the reflectance of the wiring surface is reduced by the above processing, so the laser energy is efficiently absorbed, and it is possible to deposit the CVD film with a low-energy laser beam, and absorb the laser energy with the deposition of the CVD film. Even if the surface to be covered changes from the surface of the wiring to the surface of the CVD film, damage due to bumping or the like does not occur, and the CVD wiring can be pulled out from the wiring in the semiconductor.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing a schematic configuration of a wiring cutting / connecting device for cutting / connecting the wiring of the semiconductor device. Ion beam processing equipment side that processes wiring and laser CV that forms wiring
The two devices on the D device side are separated by a central gate valve 8. Normally, the ion beam 2 uses a high-brightness ion source 1 such as a liquid metal ion source, and the ion beam 2 extracted therefrom is focused by an electrostatic lens 3 on a semiconductor device 5 as a target to a spot of 1 μm or less. . The ion beam 2 can be deflected by a deflector 4 installed under the electrostatic lens 3 and combined with the movement of the stage 6 to process an arbitrary shape on the semiconductor device 5 in an arbitrary shape. Further, on the laser CVD side, the CVD gas is supplied from the gas supply device 12, and the laser oscillator 10 supplies the vacuum chamber 1
The laser beam 14 is focused into the inside of the lens 3 through the window 11 while being focused by the lens 9, and the stage is moved to a predetermined position on the semiconductor device 5 to irradiate it to form a CVD wiring.

FIG. 1 is a diagram showing an actual wiring connection process. The first step is the wiring in the semiconductor device 5 by the ion beam 2.
It is a window opening process to expose 15. Conventionally, it has been considered that after the window opening process, the semiconductor device is immediately transported to the laser CVD side to enter the wiring forming process. However, the damage as described above occurs. Therefore, as described above, a surface treatment step for reducing the reflectance of the wiring surface is inserted. The processing performed in the surface treatment step is processing for forming irregularities on the wiring surface as shown in FIG. FIG. 2 (a) shows an embodiment in which a thin groove is processed. The groove width is preferably equal to or less than the wavelength of laser light. As an example, when an argon laser is used, the laser light wavelengths are 488 nm and 514.5 nm. Therefore, the groove width is also 0.5 μm or less. The groove of this width can focus the ion beam up to 0.1 μm,
Can be formed. Further, FIG. 2 (b) is an example in which a deep wedge-shaped groove is formed, and FIG. 2 (c) is an example in which a conical hole is formed. In both cases, since the incident laser light is reflected in the processed groove or the processed hole but is finally absorbed, a CVD film can be deposited on the exposed wiring portion even with low energy. Among them, the method of digging a conical hole is relatively easy and short-time by fixing and irradiating the ion beam focused to about 0.1 μm for a certain time after the window opening process and fixing it to the center of the exposed wiring part. It is practical because it can be processed with. However, if the reflectance is not sufficiently reduced at one point, it is effective to form a large number of holes as shown in FIG. For example, a circular through hole is opened to expose the aluminum wiring layer in advance, and the ion beam is stopped at the center of the aluminum wiring layer for 10 seconds to form a conical hole. In this example, the wiring pattern in which the aluminum wiring is exposed is used from the beginning. The exposed portion was irradiated with a laser to deposit a CVD film. The energy required for depositing this CVD film was 20% of that when the aluminum wiring was damaged at the same time as the conventional CVD film deposition, and it was possible to deposit the CVD film without damaging the underlying aluminum wiring. .

〔The invention's effect〕

According to the present invention, a CVD film can be deposited on the exposed wiring layer surface of a semiconductor device by using a low-energy laser beam, so that a favorable wiring layer can be obtained without damaging the wiring layer.
There is an effect that a CVD wiring can be formed.

[Brief description of drawings]

FIG. 1 is an explanatory view of a wiring connection process including the present invention, FIG. 2 is a sectional perspective view of a processing portion showing a processing pattern of the present invention, FIG. 3 is a schematic configuration diagram of a wiring cutting / connecting device, and FIG. The figure is an explanatory view of the wiring cutting / connecting method. 1 ... Ion source, 2 ... Ion beam, 3 ... Electrostatic lens, 4 ... Deflector, 5 ... Semiconductor device, 6 ... Stage, 7 ... Vacuum pump, 8 ... Gate valve, 9 ... … Lens, 10… Laser oscillator, 11… Window, 12… CVD gas supply device, 13… Vacuum chamber, 14… Laser beam, 15… Wiring, 16… Optical path, 17… CVD film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsuro Mizukoshi, Katsuro Mizukoshi, 292 Yoshida-cho, Totsuka-ku, Yokohama City, Hitachi, Ltd. Inside the Technical Research Institute (72) Inventor Takahiko Takahashi 1450, Kamimizuhonmachi, Kodaira City Inside the Device Development Center, Hitachi, Ltd. (56) References JP 61-237446 (JP, A) JP 60-216555 (JP, A) JP-A-60-245227 (JP, A) JP-A-59-119853 (JP, A) JP-B 7-63064 (JP, B2) JP-B 5-14416 (JP, B2) JP-B 5 -73052 (JP, B2) Japanese Patent Publication 7-12056 (JP, B2) Japanese Patent Publication 8-1928 (JP, B2)

Claims (5)

(57) [Claims] 1. A method for forming a wiring film connected to a conductor, which comprises irradiating an ion beam on the surface of the conductor to change the surface shape of the conductor, and applying the surface shape on the conductor. A wiring forming method comprising irradiating an energy beam in a material gas atmosphere to form a wiring film. 2. The wiring forming method according to claim 1, wherein the change in the surface shape of the conductor reduces the light reflectance of the conductor surface. 3. The wiring forming method according to claim 1, wherein the energy beam is a laser beam, and the wiring film is formed by laser CVD. 4. A method for connecting and forming a wiring film to a conductor covered with an insulating film, wherein the insulating film is irradiated with an ion beam to expose the conductor, and the exposed surface of the conductor is exposed to irradiation conditions. The reflectance of the surface is reduced by irradiating the changed ion beam, and on the conductor surface having the reduced reflectance.
A wiring forming method, which comprises irradiating a laser beam in a CVD gas atmosphere to form a wiring film. 5. The reflectance of the surface of the conductor is reduced by irradiating the surface of the exposed conductor with an ion beam under different irradiation conditions and processing at least one groove or hole in the surface of the conductor. The wiring forming method according to claim 4, wherein the wiring is formed.