JPH01124236A - Method and apparatus for forming wiring using laser - Google Patents

Abstract

PURPOSE:To form a wiring without causing the step-cut of the wiring ad damaging a material, by drawing the wiring by scanning, while keeping constant the distance from a laser beam irradiation point to the tip of the wiring during drawing. CONSTITUTION:A drawing line 21 being drawn by a laser CVD has a precedence part 24 growing in a drawing direction 23 from a laser irradiation point 22 converged by laser beam by heat diffusion at an appropriate moving speed, while a boundary of the drawing line 21 and a substrate material can be determined, for example, as a portion taking a maximum value of the change in brightness and darkness near the place having the laser irradiation part as a center by drawing process. Since the drawing direction 23 is previously given, the distance between the laser beam irradiation point 22 and these boundaries is computed and for example, the average of several points on a boundary line ahead of the laser beam irradiation point 22 facing a moving direction, for example, one point along the drawing direction 23 and two points crossing with a line having an angle of 60 deg. at its both ends becomes a precedence length. The precedence length increases when a laser beam intensity increases, while decreases when the moving speed increases, and increases when the concentration of a raw material gas increases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a wiring forming method using laser chemical vapor deposition (laser CVD) and an apparatus therefor.

[Conventional technology]

J as a conventional wiring forming device using laser CVO.

Techniques such as those described in Vac, Sci, Technol, 1987, Vol. 85, p. 496 (known).

Here, an argon ion laser is used as a light source, and the laser beam is condensed and irradiated through an irradiation optical system onto a substrate installed in a CVD cell filled with vapor of molecules containing metal. - By moving in the horizontal plane with the Y stage, fine metal lines can be drawn on the substrate without using a mask.

[Problem that the invention seeks to solve]

However, with conventional wiring forming equipment that uses laser CVD, on materials with different thermal conductivities, the line width may change due to differences in thermal diffusion length, the wiring may break, or damage may occur to the substrate material. There was a drawback that it gave

The purpose of the present invention is to monitor the shape of wiring drawn by laser CvD, and adjust the sweep speed of the substrate position, the concentration of source gas, and the incidence of laser light according to the size of the portion preceding the laser irradiation part in the sweep direction. Sequential control of intensity 6. :: A laser that forms wiring on materials with different thermal conductivities by keeping the line width constant and without breaking the wiring or damaging the material. An object of the present invention is to provide a wiring forming device that can be used.

[Means for solving problems]

The first aspect of the present invention is to irradiate a focused laser beam onto a substrate placed in an atmosphere containing a raw material gas for depositing a conductive substance by a chemical reaction, and to direct the laser beam relative to the substrate. A wiring forming method using a laser, which is characterized in that the wiring is drawn by scanning while maintaining a constant distance from the laser beam irradiation point to the tip of the wiring being drawn. It's a method.

The second invention is a laser light source (Ar ion laser 6) in FIG.
An optical system (condensing lens 5, first mirror 15
), a gas supply system (raw material gas flow rate control unit 10) that heats the substrate 1 with the emitted light, decomposes it with the heat, and guides vapor to the surface of the substrate 1 (raw material gas flow rate control unit 10); A reaction tank 2 is maintained in this steam atmosphere and equipped with a window 3 for introducing the emitted light, and a mechanism (an x-y stage 4, a position control unit 13) that holds this reaction tank 2 movably in a horizontal plane ), an optical system (monitoring light source 9, second
a mirror 14), a monitor light source 9 that illuminates the monitor portion, a monitor camera 7 that takes in an enlarged image of the monitor portion, and a monitor television 8 that displays the enlarged image. In the device,
An image processing unit 11 that recognizes the outline of the drawn portion in the enlarged image and measures the amount of elongation of the drawn line in the drawing direction from the laser beam irradiation point 22, and from the measured amount of elongation, Laser-based wiring characterized by comprising a control unit (basic control value setting unit 12) that determines the intensity of the laser light source, the concentration and flow rate of the raw material vapor, and the speed at which the reaction tank is moved. It is a forming device.

[Function/principle of the invention]

In the present invention, the board is monitored by video, and the elongation state of the tip of the drawn line from the laser beam irradiation position in the drawing direction is measured by droplet processing, and the elongation of the drawn line due to the difference in thermal conductivity of the board is measured. Differences in condition are determined by comparing them with standard values. If the difference in elongation is positive (negative), either correct the intensity of the laser beam to a smaller (larger) direction, or correct the moving speed of the substrate to a larger (smaller) direction, or correct the partial pressure of the raw material vapor. By correcting in the direction of decreasing (increasing) the drawing line, the amount of expansion of the drawing line can be returned to the reference value.

By setting a reference value for the amount of elongation, the substrate is not directly irradiated with laser light, and by using the drawing line as a protective film, drawing can be performed without causing damage.

The amount of expansion is a parameter that gives the line width at the tip of the drawn line, and by keeping this at a constant value, the line width can also be kept constant.

By keeping the amount of expansion at a positive value, the drawing line can be drawn in the advancing direction without any breaks.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram for clearly showing the configuration according to the present invention. In the figure, a laser beam from an Ar ion laser 6 is reflected by a first mirror 15, and is condensed and irradiated onto a substrate 1 in a reaction tank 2 by a condensing lens 5. The laser light intensity can be adjusted by an external signal. The substrate 1 used was one in which AQ wiring having a width of 3IIM and a thickness of IIIM was formed on a 5in2 thermal oxide film.

The laser beam is guided into the reaction chamber 2 through the window 3. W(CO) and steam were used as the gas for laser CVD.

The raw material gas control unit uses argon as a carrier and further dilutes it with argon, controlling the concentration of 1w(Co)s by controlling the flow rate of this diluted argon.1 Reaction tank 2 is an X-Y It is fixed on the stage 4 and can be moved by the position control unit 13 in a horizontal plane. The light from the monitor light source 9 passes through the lens 5 and illuminates the area including the laser beam irradiation section, and the reflected light from the substrate 1 is received by the monitor camera 7 through the second mirror 14 and converted into an electrical signal. is sent to the monitor television 8 and the image processing unit 11. Image processing unit 1
In step 1, the shape of the drawn wiring is pattern recognized, the size of the preceding portion from the irradiation unit in the current drawing direction (preceding portion) is calculated, and sent to the basic control value setting unit 12.

The basic control value setting unit 12 compares the leading part obtained from the optical imaging unit 11 with a preset leading part, and controls the moving speed, laser light intensity, or raw material gas concentration so that it approaches the set value.

FIG. 2 is a conceptual diagram illustrating the mechanism of the image processing section of the present invention. The drawing line 2 which is being drawn by laser CVD has a leading portion 24 that grows in the drawing direction 23 by heat diffusion from the laser irradiation point 22 where laser light is focused and irradiated at a certain appropriate moving speed. Through image processing, it is possible to determine the boundary between the drawing line 21 and the substrate material in the vicinity of the laser beam irradiation part, for example, as the part where the change in brightness takes the maximum value. Since the drawing direction 23 is given in advance, the distances from the laser beam irradiation point 22 to these boundary lines are calculated 1
For example, several points on the boundary line in front of the laser beam irradiation point 22 in the traveling direction, for example, one point along the drawing direction 23,
The average of the two points intersecting the line forming an angle of 60 mm on both sides is taken as the leading part.

The leading portion increases as the laser light intensity increases, decreases as the moving speed increases, and increases as the source gas concentration increases. An example in which the preceding section is controlled using these control parameters is shown below.

Movement speed 4-/S, incident intensity 200mV, V(Co)
On the 5in2 thermal oxide film under the condition of s partial pressure of 10 Torr,
Although the leading part became 2-, the leading part decreased near the boundary with the AQ line, and the drawn line would be broken if no feedback was applied.

When the leading portion decreases, the moving speed is decreased according to the amount of decrease. If the leading portion cannot be recovered only by reducing the moving speed, the laser beam intensity is increased to a value that does not damage the substrate as an upper limit. By applying feedback in this way, it was possible to draw a W line with a uniform width and no breaks without causing any damage even in the boundary area with the AQ line.

〔Effect of the invention〕

As is clear from the above explanation, when the present invention is used, the shape of the wiring drawn by 2χ CVD is monitored, and the sweep speed of the substrate position is determined according to the size of the portion leading in the sweep direction from the laser irradiation part. By sequentially controlling the concentration of the raw material gas and the incident intensity of the laser beam, it is possible to maintain a constant line width on materials with different thermal conductivities, without causing breaks in the wiring, and without damaging the materials. Wiring can be formed without applying any

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a drawing device used in an embodiment based on the present invention, and FIG. 2 is a conceptual diagram of direct drawing lines for explaining an image processing section based on the present invention. 1...Substrate 2...Reaction tank 3...Window 4X-Y stage 5...Condensing lens 6...Ar ion laser (laser light source) 7
...Monitor camera 8...Monitor television 9.
... Monitoring light source 10 ... Raw material gas flow rate control unit 11 ... Image processing unit 12 ... Basic control value setting unit 13 ... Position control unit 14.
...Second mirror 15...First mirror 21.
...Drawing line 24...preceding part

Claims (2)

[Claims] (1) A condensed laser beam is irradiated onto a substrate placed in an atmosphere containing a raw material gas that deposits a conductive substance through a chemical reaction, and the wiring is formed by scanning the laser beam relative to the substrate. A wiring forming method using a laser, characterized in that the wiring is drawn by scanning while keeping a constant distance from the laser beam irradiation point to the tip of the wiring being drawn. (2) A laser light source, an optical system that guides the emitted light from the laser light source to the surface of the substrate, and a gas supply that heats the substrate with the emitted light and guides vapor that decomposes and deposits metal to the surface of the substrate. a reaction tank that holds the surface of the substrate in the vapor atmosphere and has a window for introducing the emitted light, a mechanism that holds and moves the reaction tank in a horizontal plane, and the laser beam irradiation section. an optical system that monitors the surface of the substrate including a monitor light source that illuminates the monitor portion;
In the laser-based wiring forming apparatus, which includes a monitor camera that takes in an enlarged image of the monitor portion, and a monitor television that displays the enlarged image, the outline of the drawn portion in the enlarged image is recognized, and the outline of the drawn portion is recognized from the laser beam irradiation point. an image processing unit that measures the amount of elongation of the drawn line in the drawing direction; and from the measured amount of elongation, the intensity of the laser light source, the concentration and flow rate of the raw material vapor, and the amount of the reaction tank. A laser-based wiring forming apparatus characterized by comprising a control unit that determines a moving speed.