JPH0217641A - Method of correcting wiring - Google Patents

Abstract

PURPOSE:To form a conductor on the side face of the stepped part of wiring as well as on the flat parts for making it easy to suppress production of defective connections by applying a laser beam to the side of the stepped part of the wiring by bending the optical axis in wiring work. CONSTITUTION:The unneeded part of wiring is cut off by melting with a laser beam to make an opening in an insulating film on the connected part. Passing Mo(CO)6 gas, etc., into a reaction chamber 4 and applying a laser beam to the part where the wiring is formed to partially heat a substrate causes the heat decomposition of Mo(CO)6, etc., at the part where the laser beam is applied and deposits Mo or other elements to form a conductor. The laser beam is scanned while the wiring part is monitored on a TV monitor and, when the beam reaches the stepped part of the wiring, the optical axis is rotated by rotating a convergent lens 3 about the focus while moving a reflecting mirror 2. The laser beam is applied to the side face of the stepped part of the wiring to deposite a conductor in this manner. After the wiring is formed, the reflecting mirror 2 and the lens 3 are returned to their original positions to form wiring on the flat parts. This enables correcting the wiring without producing defective connections.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of repairing an integrated circuit, and more particularly to a method of repairing a wiring portion.

[Conventional technology]

Conventionally, this type of wiring repair method includes optical CVD and focused ion beam technology. FIG. 3 shows a diagram of the principle of wiring repair technology using optical CVD. Laser light generated by a laser light source 1 is reflected by a reflecting mirror 2 and guided to a converging lens 3. The converging lens 3 is for converging the laser beam. The convergent light is irradiated onto the silicon wafer 6 through the transparent window 5 at the top of the reaction chamber 4. The silicon wafer 6 is fixed to the stage 7 by vacuum suction or adhesive. Mo(Co)e or W(Co)s diluted with Ar gas is flowed into the reaction chamber. Mo is formed by a photochemical reaction in the area irradiated with laser light.
Alternatively, W is deposited to form a conductive layer.

As a laser light source, an Ar laser or a YAG laser is used.

To repair the wiring in an integrated circuit, first cut off the unnecessary wiring with a laser beam, then scan the laser beam without flowing the zero-reactive gas, which is also created by the laser beam, into the insulating film of the newly connected wiring. Wiring is thereby formed.

The method of wiring repair using optical CVD has been described above, but a similar method is also used for a method using a focused ion beam.

[Problem to be solved by the invention]

In the conventional method described above, the laser beam or ion beam is irradiated vertically, so no wiring is formed on the side wall portion. For example, when the insulating film 9 on the top of the metal wiring layer 8 is not flat and has steps as shown in FIG.
0 is not accumulated, resulting in a disconnection failure.

[Means to solve the problem]

The wiring repair method of the present invention includes means for irradiating a beam from the side surface of a wiring section in wiring repair of an integrated circuit by selective CVD of a refractory metal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

Laser light source 1 is a light source for optical CVD, such as YAG laser or Ar.
Uses a laser. The reflector 2 bends the optical axis of the light source,
It leads to the converging lens 3. The converging lens 3 focuses the laser beam onto one point. The reaction chamber 4 is a box for causing a photo-CVD reaction, and has a transparent window 5 at the top for transmitting laser light. A silicon wafer 6 is fixed on a metal stage 7 by vacuum suction or adhesive.

To correct the wiring, first cut out the unnecessary wiring using a laser beam. Next, a laser beam is used to similarly open a hole in the insulating film on the wiring at the portion to be connected.

Subsequently, Mo (Co)e or W 2 (Co)a gas is caused to flow into the reaction chamber. When a convergent laser beam is irradiated to the part where wiring is to be formed and the substrate is locally heated, Mo is formed in this part.
(Go)a or W (GO)g is thermally decomposed, Mo or W is deposited, and a conductor is formed. The laser beam is scanned while observing the wiring location on a TV monitor, etc., and the optical axis is rotated when it reaches the wiring step. That is, the reflecting mirror 2 is moved and the converging lens 3 is rotated around the focal point. In this way, the side surface of the wiring step is irradiated with laser light to deposit a conductor. After wiring is formed on the side surface portion, the reflecting mirror 2 and the converging lens 3 are returned to their original positions and wiring is performed on the flat portion. Wavelength 53.5 as a laser light source
mm YAG laser is used, and the raw material gas is Mo(Co)a.
Using this method, a Mo film with a thickness of about 4000 mm and a resistivity of about 230 μΩ can be obtained.

FIG. 2 is a diagram showing the configuration of another embodiment of the present invention. 1st
The same numbers as in the figures indicate the same components. The wiring correction procedure is the same as the embodiment shown in FIG. The difference is that the stage 7 is rotated around the rotation axis 11 when it reaches the wiring step portion. Even if the optical axis remains fixed, the stepped portion can be irradiated with laser light, and wiring can be formed on the side surface. In this embodiment, the only movable part is the stage, so the mechanism is simple and inexpensive.

〔Effect of the invention〕

As explained above, the present invention enables optical CVD to be applied to the side surface by bending the optical axis of the laser beam or tilting the silicon wafer to irradiate the side surface of the interconnect step with the laser beam.
It causes a reaction and deposits a conductor, which has the effect of suppressing disconnection defects.

Although the above explanation has been made regarding laser light, similar effects can be obtained with a focused ion beam.

FIG. 4 is a cross-sectional view of a silicon wafer for conventional wiring correction.

1...Laser light source, 2...Reflector, 3
...Convergent lens, 4...Reaction chamber, 5.
...Transparent window, 6...Silicon wafer
7... Stage, 8... Metal wiring, 9
...Insulating film, 10... Wiring material, 11
······Axis of rotation.

Agent: Patent Attorney Susumu Uchihara

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the device configuration of one embodiment of the present invention, FIG. 2 is a cross-sectional view showing the device configuration of another embodiment of the present invention, and FIG. 3 is a diagram of the device configuration for conventional wiring correction. No. 1

Claims (1)

[Claims] A wiring repair method for integrated circuits using selective chemical vapor deposition of high-melting point metals, characterized in that a beam is irradiated from the side of the wiring section.