JP2013123654A - Pattern forming method and pattern forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern forming method capable of forming fine patterns.SOLUTION: The pattern forming method where ink droplets 120 are sequentially ejected toward a base material 100 to form the patterns 110 on the base material 100 includes: a first process S11 for heating a predetermined position Pby irradiating with first laser light Lthe predetermined position Pof the base material 100; a second process S13 for ejecting the ink droplets 120 toward the predetermined position P; and a third process S14 for heating the droplets 120 by irradiating with second laser light Lthe droplets 120 of the ink that are flown. The wavelength of the first laser light Land the wavelength of the second laser light Lare different.

Description

  The present invention relates to a pattern forming method and a pattern forming apparatus for sequentially discharging ink droplets toward a base material to form a pattern of a predetermined shape on the base material.

  When forming a wiring pattern on a substrate using ink jet, a technique for quickly solidifying the droplet immediately after landing is known by preheating the spot where the droplet lands on the substrate with a laser beam or a lamp. (See, for example, Patent Document 1).

International Publication No. 2009/076023

  However, if the substrate is made of a material having a relatively low melting point such as a resin material, the substrate may not be sufficiently heated to a temperature at which the landed droplets solidify. For this reason, there is a problem that the droplets cannot be dried quickly and it is difficult to form a fine pattern.

  The problem to be solved by the present invention is to provide a pattern forming method and a pattern forming apparatus capable of forming a fine pattern.

  [1] A pattern forming method according to the present invention is a pattern forming method in which ink droplets are sequentially ejected toward a substrate to form a pattern on the substrate, and the pattern is formed at a predetermined position on the substrate. A first step of irradiating the predetermined position by irradiating a first laser beam toward the predetermined position; a second step of discharging the droplet toward the predetermined position; and toward the droplet in flight And a third step of heating the droplet by irradiating a second laser beam, wherein the wavelength of the first laser beam is different from the wavelength of the second laser beam. It is characterized by being.

  [2] In the above invention, the wavelength of the first laser beam is a wavelength having a higher absorption rate for the substrate than the absorption rate for the ink, and the wavelength of the second laser beam is the wavelength of the base. The absorption rate for the ink may be higher than the absorption rate for the material.

  [3] In the above invention, the power density of the second laser beam may be relatively lower than the power density of the first laser beam.

  [4] A pattern forming apparatus according to the present invention is a pattern forming apparatus that sequentially discharges ink droplets toward a base material to form a pattern on the base material. A first laser irradiation means for irradiating a first laser beam toward a position to heat the predetermined position; a droplet discharge means for discharging the liquid droplet toward the predetermined position; and the liquid in flight Second laser irradiation means for irradiating the droplet with a second laser beam to heat the droplet, and the wavelength of the first laser beam and the wavelength of the second laser beam And are different from each other.

  [5] In the above invention, the wavelength of the first laser beam is a wavelength having a higher absorption rate for the base material than the absorption rate for the ink, and the wavelength of the second laser beam is the wavelength of the base. The absorption rate for the ink may be higher than the absorption rate for the material.

  [6] In the above invention, the power density of the second laser beam may be relatively lower than the power density of the first laser beam.

  In the above invention, the pattern forming apparatus may include a moving unit that moves the base material relative to the droplet discharge unit.

  According to the present invention, a predetermined position on the substrate is heated in advance by the first laser beam, and the flying droplet is heated by the second laser beam, so that a fine pattern can be formed. It becomes possible.

FIG. 1 is an overall configuration diagram showing an outline of a pattern forming apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion II in FIG. FIG. 3 is a diagram showing another configuration of the pattern forming apparatus in the embodiment of the present invention. FIG. 4 is a flowchart showing a pattern forming method according to the embodiment of the present invention. FIG. 5A to FIG. 5D are diagrams showing each step of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram showing an outline of a pattern forming apparatus according to an embodiment of the present invention, and FIG.

  The pattern forming apparatus 10 according to the present embodiment is a so-called inkjet printing apparatus that forms a wiring pattern 110 on a substrate 100 by sequentially ejecting ink droplets 120 toward the substrate 100.

  As shown in FIG. 1, the pattern forming apparatus 10 includes a stage 20, an inkjet head 30, a first laser irradiation apparatus 40, a second laser irradiation apparatus 50, a temperature sensor 60, and a control apparatus 70. It is equipped with.

  The stage 20 has a holding surface 21 that holds the substrate 100 on which the wiring pattern 110 is formed. For example, an electrostatic chuck is provided on the holding surface 21, and the base material 100 placed on the holding surface 21 can be adsorbed. The stage 20 can be moved on the XY plane in the drawing by, for example, a ball screw mechanism (not shown).

Note that the holding surface 21 may hold the substrate 100 by vacuum suction or adhesion instead of electrostatic suction. When the base material 100 is thin and rich in flexibility, the entire surface of the base material 100 is preferably fixed. Further, the stage 20 is made of a transparent material, and one or both of first and second laser beams L ₁ and L ₂ described later are irradiated toward the back surface of the substrate 100 through the stage 20. May be.

  Incidentally, the base material 100 in the present embodiment is a film made of polyimide (PI) resin. In addition, the material which comprises the base material 100 is not specifically limited to this, For example, resin materials, such as an epoxy resin, a polyethylene terephthalate (PET) resin, a polyethylene naphthalate (PEN) resin, a phenol resin, a liquid crystal polymer (LCP) May be used.

  Moreover, you may comprise the base material 100 with a metal material and a semiconductor material. Examples of the metal material include aluminum, copper, gold, and solder. Examples of the semiconductor material include silicon, silicon carbide, gallium arsenide, and gallium nitride. Further, for example, the substrate 100 may be made of ceramics such as alumina, quartz glass, or the like.

  The inkjet head 30 has a nozzle 31 that faces the holding surface 21 of the stage 20. Although not shown in particular, the nozzle 31 communicates with a minute pressure chamber filled with ink, and by generating a large pressure in the pressure chamber, the ink droplet 120 passes through the opening 32 of the nozzle 31. Thus, it is possible to discharge toward the substrate 100. In addition, as a pressure generation method of the inkjet head 30, any of a piezo method, a bubble method, and an electrostatic suction method may be used.

  The diameter of the ink droplet 120 ejected from the nozzle 31 is about 0.1 to 2.0 times the minimum width of the wiring pattern 110, specifically 10 to 150 [μm], preferably 50. ~ 100 [μm]. Further, the ink droplet 120 is landed on the substrate 100 at intervals of 0.25 to 5.0 times the diameter of the droplet 120, thereby preventing the wiring pattern 110 from being interrupted. be able to.

  Incidentally, the ink in this embodiment is obtained by dispersing silver nanoparticles in an organic solvent. The ink in the present invention is not particularly limited as long as it contains a functional material such as a conductive material, a semiconductor material, and an insulating material. Here, as the conductive material, for example, among the metal species group consisting of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, zinc, titanium, and aluminum Examples thereof include any one kind or two or more kinds of metals, or an alloy composed of any two or more kinds of metals in the metal kind group. Moreover, you may use the inorganic substance containing the oxide of any 1 type or 2 types or more of the said metal seed | species group, and may use the monomer and oligomer of electroconductive polymers, such as polythiophene, polyaniline, and polypyrrole. Moreover, as an insulating material, a polyimide resin, an epoxy resin, etc. can be illustrated, for example. As the semiconductor material, for example, an inorganic semiconductor such as silicon (Si) or an organic semiconductor such as dioctylbenzothienobenzothiophene (C8-BTBT) may be used. Furthermore, as a functional material, for example, the ink may contain an alignment film of a liquid crystal panel or a color filter material, and for example, the ink may contain a biomaterial such as DNA or protein, a drug, or the like. Note that in the case where the conductive material is a metal, a metal inorganic salt or an organometallic complex may be dispersed in an organic solvent.

The first laser irradiation device 40 includes a first laser oscillator 41, a first mirror 42, and a first lens 43. Note that the configuration and layout of the optical system of the first laser irradiation apparatus 40 are not particularly limited to this. The first laser oscillator 41 is, for example, a carbon dioxide (CO ₂ ) laser oscillator capable of oscillating the _first laser light L ₁ having a wavelength of 10.5 [μm].

The first laser light L ₁ emitted from the first laser oscillator 41 is reflected by the first mirror 42 and then condensed by the first lens 43, as shown in FIG. A predetermined position (scheduled landing position) P _n on 100 is irradiated. The predetermined position P _n on the substrate 100 is a position on the substrate 100 where the ink droplets 120 ejected from the ink jet head 30 are to land, and the ink droplets 120 are drawn in the drawing direction of the wiring pattern 110. It is a position about 0.1 to 2 [mm] upstream (the left direction in the figure) from the latest landing position P _n−1 to land. This expected landing position P _n on the substrate 100 is preheated by the irradiation of the first laser light L ₁ before the ink droplet 120 is landed.

The second laser irradiation apparatus 50 also includes a second laser oscillator 51, a second mirror 52, and a second lens 53. Note that the configuration and layout of the optical system of the second laser irradiation apparatus 50 are not particularly limited to this. The second laser oscillator 51 is a fiber laser oscillator in which, for example, erbium (Er), ytterbium (Yb), thulium (Tm), or the like is doped in an optical fiber, and is a second laser beam having a wavelength of 532 [nm]. the L ₂ and it is possible to oscillate.

The second laser oscillator 51 may be a YAG laser oscillator or a YVO ₄ laser oscillator that oscillates laser light having a wavelength of 355 [nm] instead of the fiber laser oscillator, or 300 to 600 [ An excimer laser oscillator that oscillates laser light having a wavelength of nm] may be used.

The second laser beam L ₂ is emitted from the second laser oscillator 51, after being reflected by the second mirror 52 is condensed by the second lens 53, as shown in FIG. 2, the substrate the latest landing position P _n-1 of the ink droplet 120 on the 100, is irradiated to a region including a portion of the downstream side of the latest landing position P _n-1 (the right direction in FIG. 2), the the drawing direction. Therefore, the laser beam L ₂ of the second, as shown in the drawing, is irradiated a portion of the path of the ink droplets 120 to fly toward the substrate 100 from the nozzle 31 of the inkjet head 30.

The irradiation position of the second laser beam L ₂ on the substrate 100, the laser beam L ₂ of the second is not particularly limited as long as it can irradiate the ink droplets 120 in flight. For example, the second laser beam L ₂ may irradiate only the landing position P _n−1 of the ink droplet 120 on the base material 100, or a portion downstream from the landing position P _n−1. May be irradiated only.

The heating of the second ink droplet 120 by the laser beam L _2, the solvent of the droplet 120 should be suppressed so as not to bumping. Therefore, in this embodiment, the second power density of the laser beam L _2, is set to approximately 1 / 1-1 / 20 to the first power density of the laser beam L _1.

  Here, many of the resin materials constituting the substrate 100 have an absorption peak in a band of 3 to 20 [μm] in wavelength. On the other hand, when the particle diameter of the silver ink is 5 to 15 [nm], an absorption band due to localized surface plasmon resonance (LSPR) appears in a wavelength band of 300 to 600 [nm].

Therefore, in the present embodiment, the first laser beam L ₁ (wavelength: 10.5 [μm]) is more easily absorbed by the base material 100 than the ink droplet 120, whereas the second laser beam L ₁ The laser light L ₂ (wavelength: 532 [nm]) is more easily absorbed by the ink droplets 120 than the substrate 100. In other words, in the present embodiment, the wavelength of the _first laser beam L ₁ is higher in the absorption rate with respect to the base material 100 than the absorption rate with respect to the ink, whereas the second laser beam L _2. The wavelength of the first laser beam L ₁ is relatively higher than the wavelength of the second laser beam L _2. It is getting bigger.

Incidentally, when the substrate is a transparent resin substrate, a UV laser of 380 [nm] or less of the wavelength to be much absorbed in the transparent resin substrate, it is necessary to use as the first laser light L _1. Therefore, when printing an ink containing metal nanoparticles on a transparent resin substrate, the first wavelength of the laser beam L ₁ is relatively small with respect to the second wavelength of the laser beam L ₂ .

The temperature sensor 60 is composed of, for example, a thermography, and can measure the temperature of the planned landing position _Pn on the substrate 100 in a non-contact manner. The temperature sensor 60 is connected to the control device 70, and the control device 70 is configured so that the temperature of the planned landing position P _n on the base material 100 is included in the target temperature range based on the measurement result of the temperature sensor 60. In addition, the stage 20, the inkjet head 30, and the laser irradiation devices 40 and 50 are controlled.

  The control device 70 is composed of, for example, a computer having a CPU, ROM, RAM, various interfaces, and the like, and the shape (coordinate information) of the wiring pattern 110 formed on the base material 100 is stored in advance. The control device 70 controls the stage 20, the inkjet head 30, and the laser irradiation devices 40 and 50 so as to form the wiring pattern 110 on the substrate 100 by executing a predetermined program.

  Note that the configuration of the laser irradiation apparatus is not particularly limited to the above. FIG. 3 is a diagram showing another configuration of the pattern forming apparatus according to the embodiment of the present invention.

  In the example shown in FIG. 3, the laser irradiation device 80 includes a laser oscillator 81, a diffraction grating 82, a first mirror 83, a first lens 84, a second mirror 85, a neutral density filter 86, A third mirror 87 and a second lens 88 are provided.

The laser oscillator 81 is a two-wavelength laser oscillator that can oscillate two types of laser beams having different wavelengths. This two-wavelength laser oscillator 81 has light emitting / resonant portions with different active layers formed adjacent to each other in one chip, and the wavelength can be arbitrarily changed by changing the structure of the active layer. ing. The laser oscillator 81 in this example is a semiconductor laser oscillator that oscillates a near-infrared laser beam having a wavelength of 785 [nm] and a blue-violet laser beam having a wavelength of 405 [nm]. use as a laser beam L ₁ of, using the latter as the second laser beam L _2.

The laser beam oscillated by the laser oscillator 81 is split by the diffraction grating 82 into a first laser beam L ₁ and a second laser beam L ₂ . Then, the first laser beam L ₁ is reflected by the first mirror 83, then condensed by the first lens 84, and applied to the planned landing position on the substrate 100.

On the other hand, the second laser light L ₂ is reflected by the second mirror 85, passes through the neutral density filter 86, is reflected again by the third mirror 87, and then collected by the second lens 88. The region including the latest landing position of the ink droplet 120 on the substrate 100 and the portion downstream of the latest landing position in the drawing direction is irradiated. In this example, the second laser light L ₂ passes through the neutral density filter 86, so that the power density of the _second laser light L ₂ is relative to the power density of the _first laser light L _1. Lower.

The diffraction grating 82 without interposing, by providing two to exit port to the laser oscillator 81, from each of the emission port first laser beam L ₁ and the second laser beam L ₂ is emitted separately Also good.

  Further, the laser oscillator 81 oscillates near-infrared laser light having a wavelength of 1064 [nm] and green laser light having a wavelength of 532 [nm] instead of the above-described two-wavelength semiconductor laser oscillator. A fiber laser oscillator may be used.

In this fiber laser oscillator, first, to oscillate the laser beam of 1064 [nm], while emitting a laser beam of one divided as the first laser beam L ₁ by a beam splitter, the other laser beam to the nonlinear optical crystal Incident light is generated and second harmonics are generated and emitted as _second laser light L2. The laser beam L ₂ second for this case is not particularly limited to the second harmonic, or may be a higher order harmonic laser beam of such third harmonic.

  Next, a method for forming a wiring pattern in the present embodiment will be described with reference to FIGS. 4 and 5A to 5D. FIG. 4 is a flowchart of a method for forming a wiring pattern according to the embodiment of the present invention, and FIGS. 5A to 5D are diagrams showing each step of FIG.

First, in step S11 in FIG. 4, as shown in FIG. 5 (a), by the first laser irradiation apparatus 40 irradiates a first laser beam _{L 1} toward the substrate 100, the substrate 100 above The expected landing position _Pn is heated. At this time, as described above, since the wavelength of the _first laser light L _{1 is} a wavelength having a high absorption rate with respect to the base material 100, the first laser light L ₁ is efficiently absorbed by the base material 100, Thereby, the base material 100 is heated.

Next, in step S12 of FIG. 4, as shown in FIG. 5B, the substrate 20 is moved relative to the inkjet head 30 by moving the stage 20 by a predetermined amount toward the right side in the drawing, The planned landing position P _n preheated in the previous step S 11 is made to face the nozzle 31 of the inkjet head 30.

Next, in step S _< b _> 13 of FIG. 4, as shown in FIG. 5C, the inkjet head 30 ejects ink droplets 120 toward the latest landing position _Pn on the substrate 100.

The ink droplet 120 ejected from the nozzle 31 of the inkjet head 30 passes through the _second laser light L2 while flying in step S14 of FIG. At this time, as described above, the wavelength of the _second laser light L _{2 is} a wavelength that has a high absorptivity with respect to the ink, so that the second laser light L ₂ is efficiently applied to the ink droplet 120 during flight. As a result, the droplet 120 is heated.

The ink droplet 120 ejected from the nozzle 31 of the inkjet head 30 passes through the _second laser beam L2, and then reaches the latest landing position P _n on the substrate 100 as shown in FIG. Land. At this time, since the substrate 100 is preheated by the first laser light L ₁ and the ink droplet 120 is also preheated by the second laser light L ₂ , the ink is immediately after landing on the substrate 100. Begins to dry. For this reason, wetting and spreading of the ink on the substrate 100 are suppressed, and so-called coffee stain phenomenon is suppressed, so that a fine wiring pattern can be formed.

Since the next landing position P _{n + 1} on the base material 100 is moved to the irradiation position of the first laser light L ₁ by the movement of the stage 20 in step S12 in FIG. 4, while steps S13 to S14 are performed. During this, the expected landing position P _{n + 1} is preheated by the first laser beam L ₁ .

  When all the wiring patterns 110 have been drawn by repeating the drawing process of step S10 described above, the substrate 100 is put into an oven and the ink is dried at 80 ° C. in step S20 of FIG. Next, in step S30 in FIG. 4, the ink is sintered by performing a heat treatment at 250 ° C. in a nitrogen atmosphere on the wiring pattern 110 on the substrate 100. The substrate 100 on which the wiring pattern 110 is thus formed is used as, for example, a flexible printed wiring board.

As described above, in this embodiment, the ink droplet 120 is preheated by the second laser light L ₂ in addition to the preheating of the base material 100 by the first laser light L _1. when configured in a low melting point resin material, even weaken the heating of the first substrate 100 by the laser beam L _1, it is possible to compensate for the shortfall by preheating of the ink droplets 120. Therefore, wet-spreading of the ink on the substrate 100 is suppressed, it becomes possible to form a fine wiring pattern 110, the first substrate 100 by the laser beam L ₁ can be inhibited from damage Can do.

In particular, in the present embodiment, the first wavelength of the laser beam L ₁ is, the better the absorption rate to the substrate 100 than the absorption rate for the ink is a high wavelength, the base material by the first laser beam L ₁ 100 the it is possible to efficiently heat can be prevented from being heated ink droplets 120 by the laser beam L ₁ of the first.

In the present embodiment, since the wavelength of the second laser light L ₂ is higher than the absorption rate of the base material 100, the ink absorption rate is higher than the absorption rate of the ink by the second laser beam L ₂ . it is possible to heat the droplet 120 effectively, it is possible to prevent the heated substrate 100 by the laser beam L ₂ of the second.

In the present embodiment, the energy density of the second laser light L ₂ is relatively lower than the energy density of the _first laser light L ₁ , so that the solvent of the ink droplet 120 is prevented from bumping. can do.

Note that step S11 in FIG. 4 in the present embodiment corresponds to an example of the first process in the present invention, and step S13 in FIG. 4 in the present embodiment corresponds to an example of the second process in the present invention. Step S14 in FIG. 4 in the embodiment corresponds to an example of the third step in the present invention. Further, corresponds to an example of the first laser beam first laser beam L ₁ of the present invention in this embodiment, an example of a second laser beam the second laser light L ₂ of the present invention in this embodiment It corresponds to.

  Further, the inkjet head 30 in the present embodiment corresponds to an example of a droplet discharge unit in the present invention, the first laser irradiation device 40 in the present embodiment corresponds to an example of the first laser irradiation unit in the present invention, The second laser irradiation apparatus 50 in the present embodiment corresponds to an example of the second laser irradiation means in the present invention.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, the pattern forming method according to the embodiment of the present invention includes forming a wiring pattern of a flexible printed wiring board, forming a wiring pattern of a rigid printed wiring board or a flex rigid printed board, a multilayer printed wiring board, or a partial multilayer printed wiring. It can be used for forming a wiring pattern of each layer of the board, forming a wiring pattern of an interposer interposed between the chip and the main substrate, forming a pattern with an ink containing a biomaterial such as DNA or protein, or a drug.

DESCRIPTION OF SYMBOLS 10 ... Pattern formation apparatus 20 ... Stage 30 ... Inkjet head 40 ... 1st laser irradiation apparatus 41 ... 1st laser oscillator 42 ... 1st mirror 43 ... 1st lens 50 ... 2nd laser irradiation apparatus 51 ... 1st 2 of the laser oscillator 52 ... second mirror 53 ... laser beam L 2 _... the droplet L 1 _... first the second lens 60 ... temperature sensor 70 ... controller 100 ... substrate 110 ... wiring pattern 120 ... ink 2 laser light

Claims (6)

A pattern forming method for sequentially discharging ink droplets toward a substrate to form a pattern on the substrate,
A first step of heating the predetermined position by irradiating a first laser beam toward the predetermined position on the substrate;
A second step of discharging the droplet toward the predetermined position;
A third step of heating the droplet by irradiating a second laser beam toward the droplet in flight, and
The pattern forming method, wherein a wavelength of the first laser beam is different from a wavelength of the second laser beam. The pattern forming method according to claim 1,
The wavelength of the first laser light is a wavelength having a higher absorption rate for the substrate than the absorption rate for the ink,
The pattern forming method according to claim 1, wherein the wavelength of the second laser light is a wavelength having a higher absorption rate for the ink than for the substrate. The pattern forming method according to claim 1 or 2,
The pattern forming method, wherein the power density of the second laser beam is relatively lower than the power density of the first laser beam. A pattern forming apparatus that sequentially discharges ink droplets toward a substrate to form a pattern on the substrate,
First laser irradiation means for irradiating a first laser beam toward a predetermined position on the substrate to heat the predetermined position;
Droplet discharge means for discharging the droplet toward the predetermined position;
A second laser irradiation means for irradiating a second laser beam toward the droplet in flight and heating the droplet;
The pattern forming apparatus, wherein a wavelength of the first laser beam is different from a wavelength of the second laser beam. The pattern forming apparatus according to claim 4,
The wavelength of the first laser light is a wavelength having a higher absorption rate for the substrate than the absorption rate for the ink,
The pattern forming apparatus is characterized in that the wavelength of the second laser beam is higher in the absorption rate with respect to the ink than with the absorption rate with respect to the base material. The pattern forming apparatus according to claim 4, wherein:
The power density of said 2nd laser beam is relatively lower than the power density of said 1st laser beam, The pattern formation apparatus characterized by the above-mentioned.

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