JP2010190927A - Pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pattern forming method, while being a simple method that has high flexibility and high definition, however which allows formation of a thick-film pattern. <P>SOLUTION: The pattern forming method includes forming a pattern by irradiating a substrate with an energy beam, while a colloid material containing ultrafine particles is in contact with the substrate. When a pattern is formed on the substrate, gas and the colloid material are supplied alternately to the substrate by supplying bubbles comprising the colloid material onto the substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pattern forming method formed on a substrate such as an electronic device.

  In the laser drawing method, by irradiating the material in contact with the substrate with laser, at least a part of the material of the irradiated part is decomposed, dried, polymerized, crystallized, etc., causing a difference in physical properties from the unirradiated part. As a result, pattern formation is performed, and this is a technique that has been put to practical use in the production of printing blocks in the field of commercial printing.

  Examples of materials that can be patterned using a laser include colloidal liquid materials in which ultrafine particles of silver with a diameter of several nanometers are coated with a protective agent and dispersed in a suitable solvent. Can be purchased from This material is called silver ink and can be applied onto the substrate as if it were a conventional printing ink, and the protective agent covering the ultrafine silver particles was decomposed and removed by heat treatment after application. And a silver film is formed. In addition to silver, metals such as gold, copper, platinum, palladium and other precious metals, indium tin oxide known as transparent conductors, silicon oxide and titanium oxide as insulators and optical waveguide materials, As a semiconductor material, semiconductor ink in which silicon fine particles are dispersed has been actively studied.

  By using these colloidal material groups, which should be called functional inks, in combination with the laser drawing method, it is possible to form an electric wiring having a desired pattern by applying, for example, silver ink on a substrate and processing with a laser. . This is due to a process in which the colloidal material on the substrate is thermally decomposed by the energy of the laser, and the remaining silver particles are fused to form a conductive pattern.

Details of such pattern formation using colloidal ink and laser drawing are disclosed in, for example, (Patent Document 1).
JP 2006-38999 A

  However, although the above-mentioned conventional technology can form a high-definition pattern with a high degree of freedom by a simple method, a pattern film is used to reduce the resistance value of the wiring when forming a wiring using a conductive pattern. Even if the thickness is increased, if a thick pattern film is formed at a time, the pattern is incomplete, or if a thick pattern film is formed by repetition, it becomes complicated, and it is difficult to realize this.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a pattern forming method capable of forming a thick pattern with a high degree of freedom and high definition by a simple method.

  In order to solve the above problems, the present invention provides a pattern forming method for forming a pattern by irradiating an energy beam onto a substrate in contact with a colloidal material containing ultrafine particles. The gas and the colloidal material are alternately supplied onto the substrate.

  As a result, it is possible to form a thick pattern with a high degree of freedom and high definition by a simple method.

  The invention according to claim 1 of the present invention is a pattern forming method for forming a pattern by irradiating an energy beam onto a substrate in contact with a colloidal material containing ultrafine particles, and forming the pattern on the substrate. The gas and the colloidal material are alternately supplied onto the substrate.

  As a result, it is possible to form a pattern having a large film thickness with a high degree of freedom and high definition by a simple method.

  The invention according to claim 2 of the present invention is the pattern forming method according to claim 1, wherein the energy beam is irradiated onto the pattern to be formed by being irradiated from the colloidal material side supplied onto the substrate. Since the colloidal material is irradiated without being disturbed, the pattern can be formed efficiently.

  The invention according to claim 3 of the present invention is the pattern forming method according to claim 1, wherein the gas and the colloidal material are mixed and foamed and supplied onto the substrate, whereby the colloidal material and the gas are supplied onto the substrate. Can be supplied efficiently.

  The invention according to claim 1 of the present invention is the pattern forming method according to claim 1, wherein the gas is an inert gas, thereby minimizing the influence of surroundings existing during pattern formation. be able to.

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

(Example)
FIG. 1 is a conceptual diagram showing a pattern forming apparatus in an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an energy beam source, and in this embodiment, a blue semiconductor laser having a wavelength of 450 nm and a maximum output of 500 mw. In addition to such a visible light laser, an infrared ray, an ultraviolet laser, an electron beam, an ion beam, or the like can be used as an energy beam that can implement the present invention. Reference numeral 2 denotes a beam shaping optical system such as a collimator lens or an anamorphic prism. The collimator lens makes the radiated light of the semiconductor laser having a spread parallel light, and the anamorphic prism is flat in the beam cross section. It is used to adjust the emitted light of a semiconductor laser with an energy distribution to a shape close to a concentric Gaussian distribution. These optical elements are often used in systems using a semiconductor laser as a light source. Of course, a simpler optical system can be selected when the energy distribution of the beam emitted from the light source is already in a shape close to a Gaussian shape without being shaped. Reference numeral 3 denotes a condenser lens. Reference numeral 4 denotes a substrate unit which is made up of several constituent elements which will be described later. Reference numeral 5 denotes a pattern formed on the substrate. Reference numeral 6 is an imaginary line representing the luminous flux of the energy beam shaped into parallel light having an energy distribution close to a Gaussian shape by the beam shaping optical system 2, and reference numeral 7 is a focal point of the beam formed on the substrate. A given irradiation point, 8 is a control unit that controls the light source, and can control the increase / decrease in output in addition to the ON / OFF control of the light source. Reference numeral 9 denotes a mechanical movable stage as a relative position changing mechanism used for moving the irradiation point 7 with respect to the substrate unit 4 to form a pattern. As another form of the relative position changing mechanism 9, the light source side including the light source 1, the beam shaping optical system 2, and the like is held movably using a robot arm or the like, and is moved relative to the substrate unit 4. The present invention can also be realized by using a thing that moves only the lens 3 movably and moves the position of the irradiation point 7 relative to the substrate unit 4 by appropriately moving the lens 3. it can. It is also preferable to scan the beam using a polygon mirror or the like.

  Here, as an auxiliary element not shown in FIG. 1 because it is not essential for carrying out the present invention, a stand for supporting the entire mechanism, a holding and adjusting mechanism for each component, and further each of these A control mechanism such as a computer for operating the elements consistently and a control program in which the control is described in advance can be cited.

  Next, the detailed configuration of the substrate unit 4 will be described. FIG. 2 is a detailed explanatory view of the substrate unit in the embodiment of the present invention.

  In FIG. 2, reference numeral 10 denotes a substrate, and reference numeral 11 denotes a window plate. The substrate 10 in this embodiment is a general heat-resistant glass having a thickness of 1.1 mm. In carrying out the present invention, there is no particular limitation on the shape and material of the substrate, and in addition to the glass substrate, a plate made of ceramic, metal, plastic, etc., and a flexible material such as a polymer film may be used. it can. The window plate 11 needs to be transparent enough to transmit at least the beam 6 and so smooth that it does not hinder the progress of the beam 6 due to scattering or the like. In this embodiment, a glass plate having a thickness of 0.5 mm is used as the window plate 11. Reference numeral 12 denotes a spacer inserted between the substrate 10 and the window plate 11, reference numeral 13 denotes a cellular space constituted by the substrate 10, the window plate 11 and the spacer 12, and reference numeral 14 denotes a colloidal material. In this embodiment, the colloidal material 14 is obtained by coating ultrafine particles of silver with a protective agent and then dispersing it in water containing a surfactant. Although details will be described later, in the present invention, since the bubbles formed of the colloid material 14 are used, the colloid material 14 needs to be capable of forming bubbles. In this example, the colloidal material 14 is mixed in distilled water containing about 10 w% of Triton X100 as a surfactant, and the content of metal silver is adjusted to 15 to 20%. A colloidal material 14 in which silver fine particles are dispersed together with a protective agent in an aqueous material is readily available as a commercial product. Next, reference numeral 15 denotes a gas supply unit that supplies gas for generating bubbles in the cell 13, reference numeral 16 denotes a tube for conveying the gas to the cell 13, and reference numeral 17 denotes a pore for blowing the gas into the cell 13. Reference numeral 18 denotes bubbles generated in the cell 13. FIG. 3 shows a state in which bubbles are actually generated using such a substrate unit 4. FIG. 3 is an enlarged view of the substrate unit in the embodiment of the present invention, in which the substrate unit 4 in a state where bubbles are generated is viewed from the window plate 11 side. As can be seen from the figure, by supplying gas to the lower colloidal material 14, bubbles are formed adjacent to the upper part. The size and number of bubbles to be generated, and the generation speed can be controlled by the arrangement and size of the pores 17 and the amount of gas fed.

Here, in this embodiment, a so-called silver ink that becomes a conductive silver film after pattern formation is used as the colloidal material 14. Of course, what can be patterned using the pattern formation method according to the present invention is silver. It is not limited to ink, but metals such as gold, platinum, copper, palladium, rhodium, ruthenium, osmium and alloys and mixtures thereof, ITO (indium tin oxide), IZO (indium zinc oxide), and SnO ₂ compound-based conductive material (tin oxide) or the like, SiO ₂ (silicon dioxide) or SiN (silicon nitride) or TiO ₂ (titanium oxide) and Al ₂ O ₃ (alumina) ceramic-based insulating material such as, Si Ya Semiconductor materials such as GaN (gallium nitride) and CdSe (cadmium selenide) that can realize the colloidal material state described above It is possible to use the present invention for all Tondo.

  Now, before explaining the formation of the thick film, which is the gist of the present invention, an outline of pattern formation by the conventional technique will be explained, and it is difficult to form the thick film by using the conventional technique. Clarify whether it is.

  Pattern formation in the prior art is performed by first applying a colloidal metal material, for example, onto a substrate such as glass by using a film forming method such as spin coating or dip coating, and then drying the colloidal material to form a dry thin film. And the substrate is fixed to a movable stage. Then, a beam is emitted from an energy beam source such as a laser light source, and a stage is driven to perform scanning for forming a pattern. At this time, at the site irradiated with the beam on the dried colloidal material film, the protective agent covering the colloidal material is decomposed by the energy of the beam and converted into a metal film. When the pattern formation is completed, the substrate is removed from the stage and subjected to a development process for removing a portion of the colloidal material that has not been irradiated with the beam by using an appropriate solvent. The colloidal material that has not been irradiated with the beam by the solvent is dissolved again and flows away, but the portion converted into the metal film is no longer dissolved and remains on the substrate. In this way, a desired pattern is formed on the substrate. This is an outline of pattern formation by the conventional technique.

  Next, the reason why it is difficult to form a thick film by the conventional pattern forming method will be described. As already explained, the colloidal material used for pattern formation contains fine particles. These fine particles exhibit optical behavior different from that of the bulk body because of their size, and one of them is strong light absorption called plasmon absorption. For example, taking silver ink as an example, the silver ink is very dark black in the liquid state. This is due to the plasmon absorption of silver fine particles. Then, when this ink is applied onto a substrate to form a dry film, only about half of visible light is transmitted even if the thickness is about 1 μm. Therefore, if the dry film is made thick in order to form a thick film, it becomes difficult to make the beam energy reach the deep part of the film, and it becomes difficult to convert it into a metal film over the entire film thickness. Since this phenomenon is caused by the physical size of the colloidal material rather than by the material of the fine particles contained in the colloidal material, it is commonly observed in most colloidal materials. In addition, when the fine particles are a metal material, the metal film formed by the beam irradiation reflects the energy beam, which makes it difficult to form a thick film.

  This method is not a method of forming a thick film at once, but a method of forming a thick film pattern by overlapping thin film patterns, that is, a colloidal material is applied to a substrate and dried to form a dry film. It is possible to repeat the process of forming a pattern using a beam, developing it, applying a colloidal material to this substrate again, and using this as a dry film. It is difficult to select such a means as it is practically impossible, because there is a limit to the alignment accuracy for placing the two at the same place.

  As described above, in the pattern formation using the conventional technique, the film thickness of the pattern that can be formed is limited. When silver ink is taken as an example, the film thickness obtained is at most several microns. Considering the use of patterns for electrical wiring, it is desirable to increase the film thickness in order to reduce wiring resistance, and a film thickness of at most several microns is not sufficient for many applications for forming high-definition patterns. It is.

  Next, details of pattern formation according to the present invention will be described with reference to FIGS.

  The substrate unit 4 of this embodiment has a detailed structure as shown in FIG. In FIG. 2, a small amount of the colloidal material 14 is held so as to block a part of the cell 13 and the pores 17. In this state, the substrate unit 4 is fixed to a stage as the relative position changing mechanism 9. Next, supply of gas from the gas supply unit 15 is started, and bubbles 18 are generated inside the colloidal material 14 by the gas supplied into the cell 13 through the tube 16 and the pores 17. The bubble 18 generated next time by the gas sent in fills the inside of the cell 13 while moving upward, and bursts at the upper end of the cell. Due to the movement of the bubbles 18 in the cell 13, the colloidal material 14 is applied to the inner wall surface of the substrate 10 constituting the cell 13. Next, laser light as an energy beam is irradiated and the stage is driven. At the irradiation point 7, the colloidal material is decomposed and the metal film is subsequently formed, and a desired pattern 5 is formed. At this time, since the bubbles 18 are generated one after another and move in the cell 13, the bubbles 18 pass again over the pattern 5 that has become a metal film, and a new colloidal material 14 is applied onto the pattern 5. Accordingly, it is possible to form a new metal film layer on the pattern 5 by irradiating the portion of the pattern 5 to which the colloidal material is newly applied with laser light again. This process generates bubbles 18 and can be repeated many times as long as the laser beam is irradiated, and a thick film corresponding to the number of repetitions can be formed.

  At this time, the gas for forming the bubble 18 and the colloidal material 14 forming the wall surface of the bubble 18 are alternately supplied onto the pattern 5. The colloidal material 14 that is newly supplied each time the bubble 18 passes is a very small amount that forms the wall surface of the bubble 18 and can be completely converted into a metal film by the irradiated laser. The thin film is formed on the pattern 5. This will be described in detail with reference to FIGS. 4 (a) to 4 (e) are schematic diagrams for explaining the state in which the gas and the colloidal material are alternately supplied to the pattern formation site as time elapses, and FIG. 5 is a diagram of FIG. 4 (e). It is detailed explanatory drawing which expanded the pattern formation site | part.

  4 and 5, reference numeral 20 denotes a gas in the bubble, reference numeral 21 denotes a colloidal material constituting the side wall surface of the bubble substrate surface, and reference numeral A denotes a bubble wall formed between the substrate 10 and the window plate 11. It is also made of colloidal material. Reference numerals B and C are walls of other bubbles formed in the same manner as the wall A. Reference numeral 26 denotes a first layer pattern formed by the beam 6, reference numeral 27 denotes a newly applied colloidal material supplied on the first layer pattern 26, and reference numeral 28 denotes a first layer pattern and a second layer. An imaginary line indicating the boundary surface of the eye pattern, reference numeral 29 is the pattern of the second layer, and the arrows described in FIGS. 4A to 4E indicate the moving direction of the bubbles. The state of pattern formation performed sequentially will be described in detail with reference to FIGS.

  First, FIG. 4A shows an initial state in which bubbles are generated in the substrate unit 4. In the state of FIG. 4A, the inner surface of the substrate 10 is covered with a colloidal material 21. The colloidal material 21 is applied by passing through the wall A. Next, in FIG. 4B, the beam 6 is incident through the window plate 11 and the colloidal material inside the window plate 11 to form an irradiation point 7 on the inner surface of the substrate 10. At the irradiation point 7, the first layer pattern 26 is formed through the process already described. Here, the first layer pattern 26 is a first layer pattern formed on the substrate. Next, in FIG. 4C, the wall B passes over the formed first layer pattern 26. When the wall B passes over the first layer pattern 26, a thin coating film 27 of a colloidal material is newly formed on the first layer pattern 26. As shown in FIG. 4D, the first layer pattern 26 after the passage of the wall B is covered with a newly formed coating film 27 of a colloidal material. Then, as shown in FIG. 4E, the beam 6 is incident again, and a new pattern is formed on the first layer pattern 26.

  Here, FIG. 5 is an enlarged view for explaining the details of the pattern forming portion of FIG. As shown in FIG. 5, the newly applied colloidal material 27 is added to the metal by irradiation of the beam 6 to form a second layer pattern 29 so as to overlap the first layer pattern 26. At this time, the thickness of the pattern is the sum of the two layers. The patterns of the first layer and the second layer are firmly bonded and integrated.

  A pattern up to the second layer is formed through such a process. After that, the wall C forms a further colloidal material coating film on the second layer pattern 29, and the part 6 is irradiated with the beam 6, so that a thicker pattern is formed. It is.

  The example described above is a case where the colloidal material application and the pattern formation by the energy beam irradiation are sequentially performed. The size of the bubble 18, the thickness of the beam 6, the scanning speed and the scanning direction of the beam, Depending on conditions such as moving speed, the bubble wall 22 may pass through the beam 6, that is, pattern formation by colloidal material application and energy beam irradiation may be performed simultaneously. Even in such a case, since the beam 6 is converged by the condenser lens 3, the energy density is low at a place other than the irradiation point 7, and the colloidal material is decomposed and converted to metal at a place other than the irradiation point 7. There is no such reaction. For the same reason, the colloidal material applied to the inner wall surface of the window plate 11 is not converted into metal. Further, when the bubble wall 22 passes through the beam 6, a part of the beam 6 is scattered. This scattering is a very short time when the bubble wall 22 passes through the beam 6, and Since the amount of scattered light is very small, a pattern is not formed at an undesired site.

  Note that the bubbles 18 made of the colloid material pass over the substrate 10 so that the colloidal material and the gas in the bubbles 18 are alternately supplied. , The boundary portion of the bubble 18 is in contact, so that the boundary portion of the bubble 18, that is, a colloidal material is supplied.

  As described above, according to the present invention, a thick film can be formed on a substrate with a high degree of freedom even with a simple pattern forming method using a colloidal material and an energy beam.

  The film thickness of the pattern that can be formed by the present invention is not limited in principle, and it is easy to form a metal film exceeding 10 μm. Therefore, it is possible to provide a pattern forming method that can sufficiently cope with an application in which a thicker pattern is required to reduce the wiring resistance like electrical wiring.

  In order to form a thick film, a plurality of accurate beam scans are indispensable, but this can be easily realized by performing beam scans using a polygon mirror.

  In addition, since the present invention does not form a dry film of colloidal material as described in the prior art, there is a so-called development process for dissolving and removing excess material in a portion where pattern formation has not been performed using a solvent. There is also an advantage that it becomes unnecessary. It is sufficient that the substrate after the pattern formation is completed is simply cleaned using an appropriate solvent.

  In addition, the energy beam is not irradiated from the back side where the pattern is formed, but from the side of the colloidal material supplied on the pattern, so that it is not affected by the already formed pattern and is applied to the substrate. A new pattern can be efficiently formed on the pattern under the same energy beam irradiation conditions as those for forming the pattern directly.

  In addition, since colloidal material is made in the form of foam and colloidal material is supplied to the substrate surface, when energy beam is irradiated from the colloidal material side, the influence of colloidal material unnecessary for pattern formation on the optical path of energy beam. Can be minimized, and energy beam utilization efficiency can be increased.

  In this embodiment, a so-called silver ink containing metallic silver fine particles is used as a colloidal material, but there is no essential difference in the practice of the present invention even if a material other than silver ink is used. Rather, it is more preferable to suppress the oxidation of the material by using inert nitrogen or argon as a gas for generating bubbles when using a relatively easily oxidized material such as copper, or vice versa. It is even possible to more actively utilize a pattern formation method using bubbles, such as preventing oxygen from being decomposed by using oxygen as a gas in a material containing oxide fine particles.

  Finally, other requirements for carrying out the present invention will be specifically shown. However, this is only an example, and as already mentioned, various conditions for pattern formation, that is, the type and composition of colloidal material, the type and supply of gas, the configuration of the substrate unit, the type of energy beam, Intensity, scanning speed, etc. are closely related to each other. Therefore, when carrying out under other conditions, it is necessary to select optimum conditions while taking into consideration the essence of the present invention.

  A silver ink comprising a solvent containing 30 w% silver as fine particles and a mixture of water and a protective agent and water containing 10 w% Triton X100 were mixed at a ratio of 1: 1 to prepare an ink containing 15 w% metallic silver. 4 ml of this was injected into a cell constituted by two 100 mm square glass substrates with a 5 mm thick silicon rubber spacer interposed therebetween. At the bottom of the cell, silicon tubes with holes with a diameter of about 1 mm are opened at four locations at 20 mm intervals so as to be immersed in the ink, and one end is pulled out of the cell and connected to the compressor via the flow meter. did. Compressed air was flowed at a flow rate of 400 ml / min, and ink was applied to the inner wall surface of the glass with the generated bubbles. The size of bubbles generated at this time was approximately 3 to 10 mm. The substrate unit configured as described above was fixed to an XY stage.

  A semiconductor laser beam with a wavelength of 450 nm is shaped as an energy beam into a beam with parallel light and a cross-sectional energy distribution close to a Gaussian shape by a collimating optical system and an anamorphic prism, and the spot size at the irradiation point is about 30 μm by a condensing lens. The test pattern was formed by condensing and irradiating in such a manner as to reciprocate in a linear range of 10 mm in length at a linear velocity of 10 mm / sec. The intensity of the laser beam at the irradiation point was 210 mW.

  As a result of pattern formation for 1 minute while sending compressed air and generating bubbles, the test pattern formed was a kamaboko type with a width of about 50 μm, the thickest part measured using a stylus type film thickness system The film thickness was 12 μm.

  On the other hand, an ink containing 30 w% of silver as fine particles was applied onto a glass substrate by spin coating, and after drying, a pattern was formed using a light source similar to the above as an energy beam. The dry film thickness of the ink formed by spin coating was about 1 μm, and the film thickness of the obtained pattern was about 100 nm.

  As another trial, an ink containing 30 w% of silver as fine particles was applied on a glass substrate using a dispenser so as to be thicker than that obtained by spin coating, and a dry film was prepared to perform the same patterning. The film thickness of the obtained dry film was about 28 μm. When the pattern was formed by irradiating the dry film with the laser described above, about half of the pattern was peeled off by development. When the film thickness of the remaining part was measured, it was about 5 μm.

  As described above, by using the pattern forming method of the present invention, it is possible to provide a pattern forming apparatus capable of forming a thick film with a high degree of freedom and high definition by a simple method. The pattern obtained by the present invention can be used in a wide range of industrial fields such as electronic circuit boards having high-density wiring, electronic devices such as semiconductors, and optical elements such as diffraction gratings and optical waveguides.

The conceptual diagram which shows the pattern formation apparatus in the Example of this invention Detailed explanatory diagram of the substrate unit in the embodiment of the present invention Enlarged view of the substrate unit in the present embodiment The schematic diagram for demonstrating a mode that gas and a colloid material are alternately supplied to the pattern formation site | part in the Example of this invention. Detailed explanatory view in which a pattern forming portion is enlarged in an embodiment of the present invention

DESCRIPTION OF SYMBOLS 1 Energy beam source 2 Beam shaping optical system 3 Condensing lens 4 Substrate unit 5 Pattern 6 Beam 7 Irradiation point 8 Control part 9 Relative position change mechanism 10 Substrate 11 Window plate 12 Spacer 13 Cell 14 Colloid material 15 Gas supply part 16 Tube 17 Pore 18 Bubble 20 Gas in Bubble 21 Colloid Material Constructing Side Wall of Substrate Surface of Bubble 26 Layer 1 Pattern 27 Colloid Material 29 Layer 2 Pattern

Claims (4)

A pattern forming method for forming a pattern by irradiating an energy beam onto a substrate in contact with a colloidal material containing ultrafine particles, wherein the gas and the colloid are formed on the substrate when the pattern is formed on the substrate. A pattern forming method, wherein materials are alternately supplied. The pattern forming method according to claim 1, wherein the energy beam is irradiated from a side of the colloidal material supplied onto the substrate. The pattern forming method according to claim 1, wherein the gas and the colloidal material are mixed and foamed and supplied onto the substrate. The pattern forming method according to claim 1, wherein the gas is an inert gas.