JP2006332568A - Conductive pattern generation method - Google Patents

Abstract

A method of generating a conductive pattern that can easily generate a conductive pattern without using a printing apparatus for patterning, and does not require complicated processing steps, thereby realizing miniaturization of the conductive pattern. provide.
A conductive paste film is coated on a surface of a substrate with a conductive paste in which conductive powder and a thermosetting resin are uniformly dispersed. The substrate 3 is placed at a predetermined position on the base 1 with the conductive paste film 4 facing upward. The heat ray laser beam from the laser drawing device 10 disposed above the base 1 is incident on the conductive paste film 4 to thermally cure the thermosetting resin in the paste component, and the conductive powder is also sintered. . Thermosetting and sintering do not occur in the laser unirradiated portion. The sintered and unsintered are formed in a dot shape, and the sintered circuit pattern 2 is formed.
[Selection] Figure 1

Description

  The present invention relates to a conductive pattern generation method for generating a conductive pattern on an object surface using a conductive paste, for example, in order to form electrodes, wirings, and the like in electronic components and circuit boards.

In a printed wiring board used for circuit boards of various electric devices, a predetermined conductive pattern is generally formed of a conductive material on an insulating substrate such as epoxy or in the case of a multilayer substrate.
As a conventional conductive pattern generation method, for example, an etching method or a plating method is well known. According to the former etching method, by applying a resist to the copper foil surface of the insulating substrate having a copper foil formed on the surface, patterning exposure and development, and then dissolving and removing the metal foil other than the pattern with chemicals The copper foil conductive pattern is left to form. In the latter plating method, for example, as disclosed in Patent Document 1, a desired conductive pattern is formed by depositing copper plating only on a desired conductive pattern portion by electroless copper plating.
JP-A-5-90209

  Since the etching method requires a masking process for patterning, the manufacturing process is complicated, and there is a problem that equipment for patterning such as resist coating is required. Even in the plating method, since it is necessary to perform the patterning process so that the portions other than the portion where the conductive pattern is applied are not plated, the manufacturing process is complicated as in the etching method, and it is necessary to prepare a patterning apparatus separately. In particular, in these methods, since screen printing technology or the like is used for patterning, it is impossible to reduce the wiring width of the conductive pattern beyond the printing limit. There was a problem that could not be adapted.

  Therefore, in view of the above-described problems, the present invention can easily generate a conductive pattern without using a printing apparatus for patterning and without requiring a complicated processing process. It is an object of the present invention to provide a method for generating a conductive pattern that enables further miniaturization of a conductive pattern formed on a wiring board or the like in accordance with miniaturization of components.

  The present invention has been made to solve the above problems, and a first embodiment of the present invention provides a conductive paste in which conductive powder and a thermosetting resin are uniformly dispersed, and this conductive paste. Is applied to the surface of the object to form a conductive paste film, and the conductive paste film is irradiated with a heat ray laser beam to a desired pattern to form a drawing pattern in which the conductive paste is thermally cured, In this conductive pattern generation method, a conductive pattern is generated on the surface of the object by using the drawing pattern.

  A second aspect of the present invention is the conductive pattern generation method according to the first aspect, wherein the conductive powder is made of metal particles having an average particle diameter of 1 nm to several μm.

  A third aspect of the present invention is a conductive pattern generation method according to the first or second aspect, wherein the metal particles are monodispersed in the thermosetting resin.

  According to a fourth aspect of the present invention, in the second or third aspect, the metal particle is formed by coating an organic group around a metal particle nucleus, and the conductive pattern is monodispersed by the organic group. Is the method.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a beam diameter of the heat ray laser light is reduced from 1 nm to several tens of nm, and an average particle diameter of the conductive powder is from 1 nm. In the conductive pattern generation method, the line width of the drawing pattern is formed to be 100 nm or less by being adjusted to several tens of nm.

  A sixth aspect of the present invention is the conductive pattern generation method according to the second, third, or fourth aspect, wherein the metal particles are made of a noble metal element.

  A seventh aspect of the present invention is the conductive pattern generation method according to the second, third, or fourth aspect, wherein the metal particles are made of a base metal element.

  According to an eighth aspect of the present invention, in the first aspect, the thermosetting resin is any one of a phenol resin, an epoxy resin, an acrylic resin, a polyimide resin, a melamine resin, and a urea resin. This is a conductive pattern generation method.

  A ninth aspect of the present invention is the conductive pattern generation method according to any one of claims 1 to 8, wherein the conductive paste contains an organic solvent in any one of the first to eighth aspects.

  According to the conductive pattern generation method of the first aspect of the present invention, a conductive paste in which conductive powder and a thermosetting resin are uniformly dispersed is prepared, and this conductive paste is applied to the surface of an object. A conductive paste film is formed, and a heat-beam laser beam is irradiated onto the conductive paste film to a desired pattern to form a drawing pattern obtained by thermosetting the conductive paste. Since the conductive pattern is generated, the conductive pattern can be easily generated without using a pattern printing apparatus required in the conventional conductive pattern generation method and without requiring a printing process such as masking for patterning. . Moreover, since the heat ray laser beam used for pattern drawing can be narrowed down to a finer irradiation shape, the drawing pattern obtained by thermosetting the conductive paste can be miniaturized, and various electronic devices and electronic parts can be miniaturized. The conductive pattern formed on the wiring board or the like can be miniaturized in accordance with the miniaturization.

  According to the second aspect of the present invention, in the first aspect, the conductive powder is composed of metal particles having an average particle diameter of 1 nm to several μm. Accordingly, by irradiating the heat ray laser beam with a reduced beam diameter, the conductive paste can be thermally cured to form a fine line width drawing pattern.

  According to the third aspect of the present invention, in the first or second aspect, since the metal particles are monodispersed in the thermosetting resin, when the heat ray laser light is irradiated, The metal particles contained in the conductive paste do not condense, and a fine line drawing pattern can be formed.

  According to a fourth aspect of the present invention, in the second or third aspect, the metal particles are formed by coating an organic group around a metal particle nucleus and are monodispersed by the organic group. have. Since the metal particles having an organic group coating structure are excellent in dispersion stability and are in a solubilized state by being dispersed in a solvent, by adding this to the conductive paste, sintering is performed by irradiation with the heat ray laser light. The paste characteristic to perform can be comprised, and the drawing pattern formation by the said heat ray laser beam can be performed smoothly.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a beam diameter of the heat ray laser light is reduced from 1 nm to several tens of nm, and an average particle diameter of the conductive powder is set. By adjusting from 1 nm to several tens of nm, the line width of the drawing pattern is formed to be 100 nm or less. Therefore, according to the downsizing of various electronic devices and electronic components, the conductive pattern formed on the wiring board or the like Miniaturization can be realized, which contributes to the reduction of the substrate and the high-density mounting of the mounted components.

  According to a sixth aspect of the present invention, in any one of the second, third, and fourth aspects, the conductive particles of the conductive paste are made of a noble metal element such as gold, silver, palladium, or the like. By using a property material, it is possible to realize miniaturization of a conductive pattern formed on a wiring board or the like.

  According to a seventh aspect of the present invention, in any one of the second, third and fourth aspects, the conductive material of the conductive paste, wherein the metal particles are made of a base metal element, for example, copper, nickel or the like. By using, it is possible to realize miniaturization of the conductive pattern formed on the wiring board or the like.

  According to an eighth aspect of the present invention, in the first aspect, the thermosetting resin is made of any one of a phenol resin, an epoxy resin, an acrylic resin, a polyimide resin, a melamine resin, and a urea resin. By irradiation with laser light, the thermosetting resin is thermoset as the conductive paste-containing component to smoothly form a drawing pattern, thereby realizing miniaturization of the conductive pattern.

  According to the ninth aspect of the present invention, in any one of the first to eighth aspects, since the conductive paste contains an organic solvent, it differs slightly depending on, for example, the beam intensity of the heat ray laser light. By using a conductive paste adapted by appropriately adding the organic solvent to the curing conditions such as the sintering temperature, it is possible to smoothly refine the conductive pattern.

  Examples of the organic solvent in the present invention include alcohol, acetone, propanol, ether, petroleum ether, benzene, ethyl acetate, other petroleum solvents, terpineol, dihydroterpineol, dihydroterpineol acetate, butyl carbitol, cellosolves, aromatics. Use family, diethyl phthalate, etc.

  Embodiments of a method for generating a conductive pattern according to the present invention will be described below in detail with reference to the accompanying drawings.

A schematic configuration of a laser drawing apparatus 10 used in the present embodiment is shown in FIG. A conductive paste film 4 is applied to the surface of the substrate 3 on which the conductive pattern is generated with a conductive paste in which conductive powder and a thermosetting resin are uniformly dispersed. The conductive paste film 4 is applied on the surface of the substrate 3 so that the thickness of the paste coating film is 20 μm and is dried. The substrate 3 is placed at a predetermined position on the base 1 with the conductive paste film 4 facing upward. A laser drawing device 10 is disposed above the base 1. The base 1 moves forward at a constant speed in the direction of arrow c by a single axis stage moving device (not shown). An XY stage moving device that moves the base 1 two-dimensionally may be used.
A laser beam 8 emitted from a heat ray laser light source 5 such as a semiconductor is focused by a collimator lens 30 and shaped into a fine laser beam having a cross-sectional diameter of 1 μm or less. As the laser drawing apparatus 10, an apparatus capable of narrowing the beam diameter of the heat ray laser from 1 nm to several nm can be used.

The laser beam 8 is incident on the waveform shaping unit 32, and on / off control of the beam is performed by a computer signal from the computer 31. The computer 31 stores data of the circuit pattern 2 to be formed on the conductive paste film 4 as on / off binary data.
The computer signal of the binary data on / off is transmitted to the waveform shaping unit 32. The laser beam 8 passes as it is when the computer signal is on, and is blocked when the computer signal is off. On is a beam irradiation signal, and off is a non-irradiation signal. This signal form is set according to the circuit pattern to be formed. In FIG. 1, a straight line portion of the circuit pattern 2 is shown, but as schematically shown in FIG. 2, as shown in FIG. A wiring pattern including the electrode portion 21 as shown in FIG. 2B is preset as binarized data of a computer signal.

  The laser beam 8 is reflected by the reflecting mirror 34 and reaches the reflecting surface 36 a of the polygon mirror 36. The peripheral surface of the polygon mirror 36 has a large number of reflecting surfaces 36a, 36a,... Arranged in a regular polygon, and is rotated in the direction of arrow a by a motor 37. The reflected laser beam 8 shifts in the direction of arrow b as the reflecting surface 36a rotates, and returns to the original position by the next reflecting surface 36a and shifts again. With one shift, the laser beam 8 moves through the fθ lens 38 over the entire width of the irradiation mirror 9. The laser beam 8 reflected downward by the irradiation mirror 9 moves corresponding to the circuit pattern data 2 to form a drawing pattern.

  When the heat ray laser irradiation is on, a laser beam is incident on the conductive paste film 4, the thermosetting resin in the paste component of the conductive paste film 4 is thermoset, and the conductive powder is also sintered. When it is off, the laser beam is cut off, so no thermal curing or sintering occurs. This sintering and unsintering are formed in a dot shape, and the sintered circuit pattern 2 is formed. The smaller the cross-sectional diameter of the laser beam 8, the smaller the dot diameter, and the circuit pattern is formed with high accuracy while scanning the laser beam. After the formation of the sintered pattern, when the substrate 3 is immersed in an organic solvent such as ethanol or isopropanol, the metal of the conductive paste film 4 that has been irradiated with the laser beam is fixed on the substrate 3, and the laser beam is not yet irradiated. Only the irradiated part is removed. Next, the removed substrate 3 is dried to obtain a conductive pattern generated in a desired pattern. Reference holes 6 and 7 are formed in the substrate 3, and the reference positions for scanning the laser beam 8 are recognized by detecting the reference holes 6 and 7 by optical detection means (not shown).

  In the present invention, since the conductive paste film 4 is thermally cured and sintered using the heat ray laser beam 8, the conductive pattern can be formed with high accuracy and high speed without performing photomask processing, Moreover, the laser drawing apparatus 10 that is much less expensive than other drawing means, such as an electron beam apparatus, can be used, and the cost for generating the conductive pattern can be reduced. For example, in the screen printing method, it is necessary to prepare a mask material for each pattern. If the circuit pattern or the like changes, it is only necessary to change the circuit pattern data stored in the computer 31, and the desired circuit pattern can be easily controlled by computer control. In addition, it can be formed at low cost. For the laser light of the present invention, an ultraviolet light laser, a visible light laser, a near infrared light laser, an infrared light laser, or the like can be used, and a gas laser or the like can be used as a laser light source in addition to a semiconductor laser. .

  The conductive paste used for the conductive paste film 4 is prepared by uniformly dispersing conductive powder and a thermosetting resin. The conductive material A of the conductive powder is, for example, a noble metal element such as gold, silver or palladium, or a base metal element such as copper or nickel. As the conductive powder, a conductive material made of metal particles having an average particle diameter of 1 nm to several μm can be used. In particular, a conductive powder having an average particle diameter adjusted from 1 nm to several tens of nm is used, and a line width of a drawing pattern is formed to 100 nm or less by irradiation with a heat ray laser beam with a beam diameter reduced from 1 nm to several tens of nm. The formed ultrafine conductive pattern can be generated. For example, when an average particle diameter is 5 nm, a conductive line having a line width of about 18 nm or less can be generated by irradiating a beam diameter of 10 nm, or when an average particle diameter is 30 nm, by irradiating a beam diameter of 40 nm. Conductive lines having a line width of about 90 nm or less can be generated.

In the present invention, in order to prevent the line width from becoming thick or non-uniform when the metal particles condense during laser irradiation, conductive powder in which metal particles are monodispersed in a thermosetting resin is used. It is preferable to do this. In particular, a conductive material composed of metal particles formed by coating organic groups around the metal particle core can be used. For example, as disclosed in JP-A-10-183207, a metal organic compound (naphthenate, octylate, stearate, benzoate, n-decanoate, metal ethoxide, metal Organic coated metal fine particles having a structure coated with acetylacetonate or the like are excellent in dispersion stability and can provide a conductive paste that can be used under low-temperature sintering conditions. If a conductive paste in which metal particles are monodispersed in a thermosetting resin is used, the metal particles in the paste components do not condense due to the irradiation of heat ray laser light, and the local heating by laser light is effectively used. , Heat conduction is efficiently performed and dissolution of metal particles is promoted, and sintering is performed smoothly under a relatively low temperature condition by laser light, and a conductive pattern with a stable line width is surely miniaturized. It can be carried out.

  As the thermosetting resin B, a phenol resin, an epoxy resin, an acrylic resin, a polyimide resin, a melamine resin, a urea resin, or the like can be used. As a combination (A, B) of the conductive material A and the thermosetting resin B, (silver, phenol resin), (gold, epoxy resin), (copper, acrylic resin), (nickel, polyimide resin), (iron) , Melamine resin), (carbon, urea resin) and the like.

  By appropriately adding an organic solvent to the conductive paste, it can be adapted to curing conditions such as slightly different sintering temperatures depending on the beam intensity of the heat ray laser beam. The organic solvent is preferably a solvent that can uniformly disperse the conductive powder. For example, alcohol, acetone, propanol, ether, petroleum ether, benzene, ethyl acetate, other petroleum solvents, terpineol, dihydroterpineol, dihydroterpineol acetate , Butyl carbitol, cellosolves, aromatics, diethyl phthalate, etc. are used.

  In the above embodiment, an experiment was conducted on how the conductive pattern generation state is affected when the moving speed of the substrate 3 changes. FIG. 3 shows an SEM (scanning electron microscope) photograph of a conductive line pattern when an experiment was conducted using a conductive paste containing silver powder having an average particle diameter of 1 μm and a phenol resin as a conductive material. In this experiment, a semiconductor laser beam oscillated with a wavelength of 810 nm and a surface light amount of 300 mW on the irradiated surface was used. It is generated by the movement speed of the substrate 3 and the beam irradiation when the substrate 3 is moved in a certain direction while irradiating a test spot on the conductive paste coating surface of the substrate 3 with a laser beam having a beam diameter of about 100 μm. The state of the conductive wire (line width: about 200 μm) was confirmed by SEM photography. (3A), (3B), (3C), and (3D) in FIG. 3 are cases where the moving speed is 8 mm / s, 4 mm / s, 2 mm / s, and 1 mm / s, respectively. From these photographs, it was found that even if the moving speed was increased, the conductive wire was obtained in almost the same generation state due to the short-time sintering effect by local heating of the laser beam, and high-speed generation was possible.

  Next, in the said embodiment, confirmation measurement of the appropriate wavelength area | region of irradiation laser light was performed. FIG. 4 shows a paste coating film formed by applying a conductive paste containing gold powder having an average particle diameter of 1 μm and an epoxy resin to a conductive material on the substrate surface, and only the epoxy resin is applied to the substrate surface. The relationship between the UV wavelength (nm) and the reflectance R (%) when a reflectance comparison measurement experiment is performed using a resin coating film is shown. For this reflectance measurement, UV3150 (manufactured by Shimadzu Corporation) and an integrating sphere were used as a measuring device. (4A) and (4B) in FIG. 4 show changes in reflectance of the paste coating film and the resin coating film, respectively. From this measurement result, it can be seen that the resin coating film has a large reflectance when the region exceeds 700 nm, but the paste coating film is stable without changing from around 780 nm to about 1800 nm. Therefore, it can be said that it is preferable to use a laser beam having a wavelength region of 780 to 1800 nm in the present invention.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications, design changes, and the like are included in the technical scope without departing from the technical idea of the present invention.

  According to the first aspect of the present invention, it is possible to easily generate a conductive pattern without using a pattern printing apparatus and without requiring a printing process such as a mask process for patterning, and various electronic devices. In addition, it is possible to provide a method for generating a conductive pattern that can realize miniaturization of a conductive pattern formed on a wiring board or the like in accordance with miniaturization of an electronic component.

  According to the second aspect of the present invention, the conductive paste is thermally cured by irradiating with a reduced beam diameter of the heat ray laser light in accordance with the average particle diameter of the conductive powder, thereby reducing the line width. It is possible to provide a method for generating a conductive pattern capable of forming a fine drawing pattern.

  According to the third aspect of the present invention, the metal particles contained in the conductive paste do not condense during the irradiation with the heat ray laser beam, and a fine drawing pattern with a line width can be formed. A method for generating a conductive pattern can be provided.

  According to the 4th form of this invention, the electroconductivity which can perform the drawing pattern formation by the said heat ray laser beam smoothly using the electrically conductive paste provided with the paste characteristic sintered by irradiation of the said heat ray laser beam. A pattern generation method can be provided.

  According to the fifth aspect of the present invention, it is possible to reduce the size of the conductive pattern by forming the line width of the drawing pattern to 100 nm or less, and to contribute to the reduction of the substrate and the high-density mounting of the mounted components. A pattern generation method can be provided.

  According to the sixth or seventh aspect of the present invention, a fine conductive pattern formed on a wiring board or the like by using a conductive material of a conductive paste in which the metal particles are made of a noble metal element or a base metal element. It is possible to provide a method for generating a conductive pattern that can be realized.

  According to the eighth aspect of the present invention, the thermosetting resin is thermally cured as the conductive paste-containing component by irradiation with heat ray laser light, and the drawing pattern is smoothly formed, and the conductive pattern is refined. It is possible to provide a method for generating a conductive pattern that can realize the above.

  According to the ninth aspect of the present invention, for example, a conductive paste adapted by appropriately adding the organic solvent to curing conditions such as slightly different sintering temperatures depending on the beam intensity of the heat ray laser light. By using the conductive pattern, it is possible to provide a method for generating a conductive pattern that can smoothly miniaturize the conductive pattern.

It is a schematic block diagram of the laser drawing apparatus 10 used for embodiment of this invention. It is a figure which shows typically the example of a wiring pattern produced | generated in the said embodiment. It is a SEM photograph of a conductive line pattern showing an influence experiment of a substrate moving speed performed in the embodiment. It is a measurement graph of the reflectance R (%) change with respect to UV wavelength (nm) which shows the result of the reflectance comparative measurement experiment of the paste coating film and resin coating film which were performed in the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Circuit pattern 3 Substrate 4 Conductive paste film 5 Heat ray laser light source 6 Reference hole 7 Reference hole 8 Laser beam 9 Irradiation mirror 10 Laser drawing apparatus 20 Wiring pattern 21 Electrode part 30 Collimator lens 32 Waveform shaping unit 31 Computer 32 Waveform forming unit 34 Reflecting mirror 36 Polygon mirror 36a Reflecting surface 37 Motor

Claims (9)

  Prepare a conductive paste in which conductive powder and thermosetting resin are uniformly dispersed, and apply this conductive paste to the surface of the object to form a conductive paste film. A conductive pattern generation method comprising: forming a drawing pattern obtained by irradiating a desired pattern with heat ray laser light to thermally cure the conductive paste, and generating a conductive pattern on the surface of the object using the drawing pattern.   The conductive pattern generation method according to claim 1, wherein the conductive powder is made of metal particles having an average particle diameter of 1 nm to several μm.   The conductive pattern generation method according to claim 1, wherein the metal particles are monodispersed in the thermosetting resin.   4. The conductive pattern generation method according to claim 2, wherein the metal particle is configured by coating an organic group around a metal particle nucleus and is monodispersed by the organic group.   By reducing the beam diameter of the heat ray laser light from 1 nm to several tens of nm and adjusting the average particle diameter of the conductive powder from 1 nm to several tens of nm, the line width of the drawing pattern is formed to 100 nm or less. The conductive pattern production | generation method in any one of Claims 1-4.   The conductive pattern generation method according to claim 2, 3 or 4, wherein the metal particles are made of a noble metal element.   The conductive pattern generation method according to claim 2, 3 or 4, wherein the metal particles are made of a base metal element.   The conductive pattern generation method according to claim 1, wherein the thermosetting resin is one of a phenol resin, an epoxy resin, an acrylic resin, a polyimide resin, a melamine resin, and a urea resin.   The conductive pattern generation method according to claim 1, wherein the conductive paste contains an organic solvent.