JP2010094621A - Pattern forming method and pattern forming apparatus - Google Patents

Abstract

The present invention provides a pattern forming method and a pattern forming apparatus for improving the drying efficiency of droplets in flight in a pattern forming method for drying droplets in flight by irradiating a droplet in flight with laser light.
A reference position DP is provided in a target path TL which is a flight path of a droplet D, a nozzle side of the reference position DP is set to a temperature rising area A1, and a drawing surface GSa side of the reference position DP is set to an evaporation area A2. Partition. The laser irradiation unit irradiates high-absorption laser beams Lha and Lhb having a wavelength λ1 having a relatively high absorption rate with respect to the droplet D in the temperature rising region A1, and is relatively relative to the droplet D in the evaporation region. Are irradiated with low absorptance laser beams Lla and Llb with a wavelength λ2 having a low absorptance.
[Selection] Figure 8

Description

  The present invention relates to a pattern forming method and a pattern forming apparatus for irradiating a droplet in flight with laser light.

  A multilayer substrate made of low temperature co-fired ceramics (LTCC) has excellent high-frequency characteristics and high heat resistance, and thus is widely used for a substrate of a high-frequency module or an IC package. Such an LTCC multilayer substrate is generally manufactured by laminating green sheets on which a circuit pattern is drawn using metal ink and firing them together.

In the step of drawing the circuit pattern, a so-called ink jet method has been proposed in which metal ink is ejected as fine droplets in order to increase the density of the circuit pattern (for example, Patent Document 1). In the ink jet method, a circuit pattern is drawn by discharging a droplet having a capacity of several to several tens of picoliters from a discharge head in which a large number of nozzles are arranged. The ink jet method enables further miniaturization of circuit patterns and narrower pitches by changing the droplet discharge position.
JP 2005-57139 A

  By the way, in order to form a high-definition pattern using the ink jet method, it is preferable to reduce the landing diameter by quickly drying the discharged droplets and suppressing wetting spread on the substrate. As one method, a method of irradiating a droplet in flight ejected from an ejection head with laser light to promote drying of the droplet during flight has been studied. When evaporating a desired amount of evaporation component using such a method, the minimum energy required for the laser beam can be roughly defined according to the desired amount, so that it is possible to improve the utilization efficiency of the laser beam. A mode in which the minimum energy is given to the droplet in flight is preferable.

  On the other hand, as the cross-sectional intensity distribution of the laser light described above, a circular normal distribution (Gaussian distribution) in which the intensity near the center of the laser light is the highest is generally used. When a laser beam having such a cross-sectional intensity distribution is irradiated onto a droplet in flight, the discharged droplet first rises in temperature at the base of the Gaussian distribution and then passes through the peak region of the Gaussian distribution. Therefore, when the heated droplet passes through the peak region, excessive energy that greatly exceeds the heat of vaporization is supplied to the droplet per unit time, and the droplet solvent So-called bumping occurs, in which a phase transition such as an evaporation component or the like occurs instantaneously in the entire droplet, and the droplet itself is scattered. On the other hand, in order to prevent such bumping, a method of further suppressing the intensity of the laser light so as not to exceed the heat of vaporization in the peak region of the Gaussian distribution can be considered. However, in such a case, although bumping in the peak region can be prevented, the intensity of the entire laser beam itself is reduced, so that the temperature of the droplet is difficult to rise even at the bottom of the Gaussian distribution, and as a result Insufficient drying.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a droplet forming method in a pattern formation method for irradiating a flying droplet with a laser beam to dry the flying droplet. It is an object to provide a pattern forming method and a pattern forming apparatus for improving the drying efficiency of the film.

  In the pattern forming method of the present invention, a liquid droplet containing an evaporation component and a pattern forming material is ejected from a nozzle toward a drawing object, and a predetermined amount of the laser beam is irradiated to the droplet in flight. A pattern forming method for forming a pattern on an object to be drawn by evaporating an evaporation component from the droplet, wherein the liquid material has an absorptance different depending on a wavelength of an irradiated laser beam, and the laser The light is a plurality of laser beams having different wavelengths, and the closer to the nozzle, the greater the energy absorbed by the droplet on the path connecting the landing position of the droplet on the drawing target and the nozzle. Thus, the gist is to irradiate the plurality of laser beams.

  In the pattern formation method in which droplets are dried by irradiating a laser beam onto the droplets in flight to evaporate the evaporation components from the droplets in flight, when the temperature of the evaporation component of the droplets is close to the boiling point The drying of the droplet proceeds efficiently. According to the pattern forming method of the present invention, since a laser beam having a relatively high absorptance is irradiated to a droplet that has just been ejected, the energy that is applied to the droplet is effectively reduced immediately after ejection. Can be converted to In addition, since laser light with a relatively low absorption rate is irradiated as the flight time elapses, higher intensity laser light is used to continue supplying predetermined thermal energy such as vaporization heat to the droplets. It is also possible to control the temperature of the droplet itself with high accuracy. Therefore, according to such a method, the evaporation component contained in the discharged droplet can be quickly raised to near the boiling point in a short time from the time of discharge. As a result, it is possible to devote much of the limited flight period from when the droplet is ejected to landing to the evaporation process of the evaporation component, and to suppress bumping during the flight period. Therefore, the drying efficiency of droplets during flight can be improved.

  In this pattern forming method, the plurality of laser beams are irradiated with a laser beam having a wavelength with a high absorption rate of the evaporating component ahead of a laser beam having a wavelength with a low absorption rate of the evaporating component. Is the gist.

  According to this pattern forming method, the absorptance with respect to the droplet can be changed on the time axis. Therefore, in order to realize the drying of the droplets as described above, it is natural that the laser light irradiation region of each wavelength is partitioned on the path of the liquid droplets. It is also possible to use a mode of overlapping on the droplet path. That is, the degree of freedom related to the irradiation range of each laser beam can be expanded.

  In this pattern forming method, the irradiation with the plurality of laser beams is performed by using a laser beam having a wavelength with a high absorption rate of the liquid material on the drawing object rather than a laser beam having a wavelength with a low absorption rate of the evaporation component. The gist is that irradiation is performed at a position close to the nozzle on a path connecting the landing position of the droplet and the nozzle.

  According to this pattern forming method, the absorptance with respect to the droplet can be changed on the coordinate axis of the flight path. Therefore, to realize the drying of the droplets as described above, use a mode in which the laser light of each wavelength is irradiated toward the droplet path at the same timing or is continuously irradiated to the same path. Therefore, the degree of freedom related to the irradiation timing of each laser beam can be expanded. When combined with a mode in which the absorptivity for droplets is changed on the time axis, both the irradiation timing and irradiation area of the laser light of each wavelength are controlled, so that the dry state of the droplets can be accurately reproduced. It can also be made.

The gist of this pattern forming method is that the liquid material has a high absorptance of visible light with respect to infrared light.
According to the present invention, by irradiating laser light, which is visible light, on the side close to the nozzle, the evaporation component contained in the discharged droplet can be quickly raised to near the boiling point in a short time from the time of discharge.

  In this pattern formation method, the evaporation component of the liquid includes an aqueous component that is a polar solvent and an organic component that is a nonpolar solvent, and the aqueous component is visible light with respect to the organic component. The main point is that the absorption rate is high.

  An aqueous component having a higher intermolecular force than an organic component generally has a higher heat of vaporization than an organic component. Therefore, the aqueous component contained in the evaporation component requires a relatively high heat of vaporization even after reaching the vicinity of its boiling point, so it takes a longer time to evaporate than the organic component. It is said. On the other hand, an organic component having a lower intermolecular force than an aqueous component generally has a lower heat of vaporization than an aqueous component. Therefore, the organic component contained in the evaporating component evaporates quickly after reaching the vicinity of the boiling point, and thus evaporates in a shorter time than the aqueous component. According to this pattern formation method, by irradiating laser light, which is visible light, on the side close to the nozzle, the aqueous component described above is heated in advance, so that the drying speed of the droplet itself is accelerated. Can do. In addition, since the organic component described above is subsequently heated, drying can be promoted over the entire droplet.

  In this pattern formation method, laser light having a wavelength with a high absorption rate of the liquid material raises the droplets to a target temperature that is the highest temperature at which the droplets do not boil, and the absorption rate of the evaporation component is increased. The gist of the low-wavelength laser light is to supply vaporization heat to the droplets.

  According to this pattern formation method, the amount of heat applied during flight is limited to an amount corresponding to the desired evaporation amount, and the evaporation component contained in the discharged droplets can be quickly brought close to the target temperature from the time of discharge. Can be raised. Therefore, it is possible to improve the drying efficiency of the droplets in flight, and to reliably prevent the droplets from bumping.

  The pattern forming apparatus of the present invention includes a discharge head that discharges a liquid droplet containing an evaporation component and a pattern forming material from a nozzle toward a drawing target, and a laser beam applied to the droplet in flight. A laser irradiation unit that evaporates a predetermined amount of the evaporation component, and forms a pattern by landing the droplets on the drawing object, wherein the liquid material emits laser light to be irradiated The absorptance varies depending on the wavelength, and the laser irradiator is configured so that the closer the droplet is to the nozzle on the path connecting the landing position of the droplet on the drawing target and the nozzle, The gist of the present invention is to irradiate a plurality of laser beams having different wavelengths toward the path so that the absorptance with respect to the light increases.

On the path connecting the landing position of the droplet on the drawing object and the nozzle, the closer to the nozzle, the greater the energy absorbed by the droplet.
The pattern forming apparatus irradiating the plurality of laser beams toward the path.

In a pattern forming device that dries a droplet by irradiating a laser beam onto the flying droplet and evaporating the evaporation component from the flying droplet, when the temperature of the evaporation component of the droplet is near the boiling point The drying of the droplet proceeds efficiently. According to the pattern forming apparatus of the present invention, since a laser beam having a relatively high absorptance is irradiated to a droplet that has just been ejected, the energy applied to the droplet is effectively converted to thermal energy immediately after ejection. Can be converted. Moreover, since laser light with a relatively low absorptance is irradiated as the flight time elapses, higher intensity laser light can be used to continue supplying predetermined thermal energy to the droplets, The temperature of the droplet itself can be controlled with high accuracy. Therefore, according to such a configuration, the evaporation component contained in the discharged droplet can be quickly raised to near the boiling point in a short time from the time of discharge. As a result, it is possible to devote much of the limited flight period from when the droplet is ejected to landing to the evaporation process of the evaporation component, and to suppress bumping during the flight period. Therefore, the drying efficiency of droplets during flight can be improved.

(First embodiment)
Hereinafter, a first embodiment in which the pattern forming apparatus of the present invention is embodied as a droplet discharge device will be described with reference to FIGS. FIG. 1 is a diagram schematically showing a perspective structure of a droplet discharge device. FIG. 2 is a graph showing the relationship between the absorptance and wavelength of aqueous silver ink, which is a conductive ink. FIG. 3 is a perspective view showing a perspective structure of the ejection head of this embodiment, and FIG. 4 is a partial sectional view showing an internal sectional structure of the ejection head. FIG. 5 is a plan view showing the arrangement relationship between the green sheet, which is a drawing object, and the ejection head.

  As shown in FIG. 1, a stage 11 that can reciprocate along the longitudinal direction of the base 11 is mounted on a base 11 of a droplet discharge device 10 as a pattern forming apparatus. In the present embodiment, the longitudinal direction of the base 11, the upper right direction in FIG. 1 is the + X direction, and the opposite direction to the + X direction is the −X direction. Further, it is a horizontal direction orthogonal to the + X direction, and the upper left direction in FIG. 3 is referred to as a + Y direction, and the opposite direction to the + Y direction is referred to as a −Y direction. Further, the upper direction in the vertical direction is defined as the + Z direction, and the direction opposite to the + Z direction is referred to as the −Z direction.

  On the upper surface of the stage 12 mounted on the base 11, a green sheet GS as a drawing object is positioned and fixed to the stage 12 with the drawing surface GSa facing upward. The stage 12 scans the positioned green sheet GS in the + Y direction or the −Y direction at a predetermined speed when a stage motor (not shown) provided on the base 11 rotates forward or reverse.

  A guide member 13 formed in a gate shape is installed on the upper side of the base 11 along the + X direction, and an ink tank for supplying the conductive ink Ik as a liquid material is provided on the upper side of the guide member 13. 14 is disposed. The ink tank 14 stores the conductive ink Ik composed of a dispersion system of conductive fine particles, and supplies the stored conductive ink Ik to the discharge head 15 while adjusting a predetermined temperature under a predetermined pressure.

  The conductive fine particles as the pattern forming material are fine particles having a particle diameter of several nm to several tens of nm. For example, silver, gold, copper, platinum, palladium, rhodium, osmium, ruthenium, iridium, iron, tin, cobalt, A metal such as nickel, chromium, titanium, tantalum, tungsten, indium, or an alloy thereof can be used.

  As the dispersion medium as the evaporation component, a dispersion medium having a function of uniformly dispersing the conductive fine particles and having viscosity and moisture retention capable of forming droplets can be used. As such a dispersion medium, for example, an aqueous solution system in which an aqueous component that is a polar solvent is a main component and an organic component that is a nonpolar solvent such as a humectant is added thereto can be used. Further, an organic solvent system in which an organic component which is a nonpolar solvent such as tetradecane is a main component and an organic component such as the humectant is added thereto can be used. In the present embodiment, an example in which a so-called aqueous silver ink in which silver fine particles are used as conductive particles and the above aqueous solution system is used as a dispersion medium is used as the conductive ink Ik will be described.

  As shown in FIG. 2, the conductive ink Ik of this embodiment has a high absorption rate of 95% or more in the visible region between 300 nm and 700 nm, and the near wavelength region from 700 nm to the long wavelength side. It has a relatively low absorption rate in the infrared and infrared regions.

When irradiating the conductive ink Ik having such absorption characteristics with light in the visible region, most of the light in the visible region is absorbed by the conductive ink Ik so as to be converted into thermal energy of the conductive ink Ik. become. Therefore, for such a request to dry the conductive ink Ik in a short time, that is, to a request to raise the temperature of most of the evaporation components in the conductive ink Ik to near the boiling point in a short time, the conductive ink Ik. In contrast, it is effective to irradiate light in the visible region first.

  On the other hand, when the conductive ink Ik having such absorption characteristics is irradiated with light in the near infrared region or infrared region, only a part of the light in the near infrared region or infrared region is applied to the conductive ink Ik. It is absorbed and converted into thermal energy of the same conductive ink Ik. Therefore, in response to a request to continue to dry the conductive ink Ik at a constant drying speed while suppressing the bumping of the conductive ink Ik, that is, energy corresponding to heat of vaporization in a part of the evaporated component near the boiling point. Is effective to irradiate the conductive ink Ik with light in the near-infrared region or in the infrared region where the change in drying speed is small with respect to the variation in intensity. is there.

  In addition, an aqueous component having an intermolecular force higher than that of an organic component generally has a higher heat of vaporization than an organic component. Therefore, the aqueous component contained in the evaporation component requires a relatively high heat of vaporization even after reaching the vicinity of its boiling point, so it takes a longer time to evaporate than the organic component. It is said. On the other hand, an organic component having a lower intermolecular force than an aqueous component generally has a lower heat of vaporization than an aqueous component. Therefore, the organic component contained in the evaporating component evaporates quickly after reaching the vicinity of the boiling point, and thus evaporates in a shorter time than the aqueous component. Therefore, in the case where the water-based component is a main component as in the conductive ink Ik of the present embodiment, the conductive ink Ik is heated in advance by heating the water-based component in advance with the above-described light in the visible region. It is also possible to accelerate the drying speed of itself. Further, since the organic component as the additive is subsequently heated by light in the near infrared region or infrared region, drying can be promoted over the entire conductive ink Ik.

  A carriage 16 that can move in the + X direction and the −X direction is mounted on the guide member 13, and an ejection head 15 is mounted on the carriage 16. The carriage 16 scans the ejection head 15 in the + X direction or the −X direction when a carriage motor (not shown) provided on the guide member 13 rotates forward or backward.

  As shown in FIG. 3, the ejection head 15 includes a head substrate 17 that is positioned and fixed to the carriage 16 and extends in the + X direction, and a head body 20 that is supported by the head substrate 17. The head substrate 17 has a connection terminal 17 a at the end in the −X direction, and various control signals from the outside are input to the head main body 20 from the connection terminal 17 a and various detection signals from the head main body 20. Is output from the connection terminal 17a to the outside.

  A nozzle plate 21 disposed so as to face the green sheet GS is attached to the bottom of the head body 20. The nozzle plate 21 is configured such that when the head body 20 is disposed immediately above the green sheet GS, the bottom surface (hereinafter simply referred to as the nozzle forming surface 21a) and the drawing surface GSa are substantially parallel. A flight space of the droplet D, which is a space sandwiched between the nozzle forming surface 21a and the drawing surface GSa, is formed. Further, when the head main body 20 is disposed immediately above the green sheet GS, the nozzle plate 21 sets a platen gap PG, which is a distance between the nozzle forming surface 21a and the drawing surface GSa, to a predetermined distance (see FIG. 4, this embodiment). In the form, it is maintained at 1000 μm). On the nozzle forming surface 21a of the nozzle plate 21, a plurality of nozzles N penetrating the nozzle plate 21 in the Z direction are arranged at equal intervals along the X direction at a nozzle pitch Dx.

As shown in FIG. 4, the head body 20 includes a cavity 22 as a storage chamber, a vibration plate 23, and a piezoelectric element PZ as a pressure generating element above each nozzle N. Each cavity 22 is connected to a common ink tank 14 via a supply tube 20T, and thereby accommodates the conductive ink Ik from the ink tank 14 and supplies the conductive ink Ik to each nozzle N. . The vibration plate 23 vibrates the meniscus of the nozzle N along with the expansion and contraction of the volume of the cavity 22 by vibrating the region facing each cavity 22 in the Z direction. Each piezoelectric element PZ is supplied with a driving voltage COM (see FIG. 10) that is a voltage waveform that defines the contraction amount, contraction speed, extension amount, and extension speed. Each time the signal is input to the element PZ, the piezoelectric element PZ contracts and expands in the Z direction, and the diaphragm 23 vibrates in the Z direction.

  In the ejection head 15 having such a configuration, when each piezoelectric element PZ contracts and expands in the Z direction, a part of the conductive ink Ik accommodated in each cavity 22 has a size and speed corresponding to the drive voltage COM. The droplets D are discharged from the nozzle N. The droplet D discharged from the nozzle N flies in the above-described flight space and lands on the drawing surface GSa of the green sheet GS. At this time, the droplet D ejected from the nozzle N can reliably fly along the Z direction from the nozzle N by the resultant force of the external force applied to the droplet D acting only in the Z direction. It flies over the target path TL which is a virtual line including the nozzle N and extending in the Z direction. On the other hand, when the resultant force of the external force applied to the droplet D acts greatly in the direction intersecting the Z direction, the droplet D discharged from the nozzle N deviates from the target path TL according to the action of the resultant force. Flying over the route, the so-called flight bend is a factor that impairs the accuracy of the landing position.

  As indicated by a two-dot chain line in FIG. 5, the drawing surface GSa of the green sheet GS is virtually divided by a dot pattern lattice DL which is a two-dimensional rectangular lattice. The dot pattern lattice DL is a virtual lattice in which the lattice interval in the + X direction and the lattice interval in the + Y direction are set at predetermined intervals. For example, the + X-direction grid spacing of the dot pattern grid DL is defined by the nozzle pitch Dx, and the + Y-direction grid spacing of the dot pattern grid DL is the product of the droplet D ejection period and the scanning speed of the stage 12. Is defined by the discharge pitch Dy calculated from When such a dot pattern grid DL is scanned by the stage 12, the ejection head 15 described above is arranged so that each grid point T of the dot pattern grid DL crosses the target path TL (nozzle arrangement direction), and each nozzle The selection of whether or not to discharge the droplet D from N toward the drawing surface GSa is set for each lattice point T. A flight path of the droplet D is formed by an imaginary line connecting the nozzle N and the lattice point T which is the target position. In FIG. 5, for convenience of explaining each lattice point T of the dot pattern lattice DL, the lattice interval of the dot pattern lattice DL and the nozzle pitch Dx of the ejection head 15 are shown sufficiently enlarged.

  In order to effectively evaporate a desired amount of the evaporated component from the droplet D ejected from the nozzle N, first, the temperature of the droplet D at room temperature is set to the highest temperature within the range where the liquid does not boil. For example, a first heat quantity q1 that is a heat quantity for raising the temperature of the droplet D at room temperature to the boiling point of the evaporation component is required. Next, in order to prevent bumping of the droplet D heated by the first heat quantity q1, the latent heat (vaporization heat) is used to smoothly transition the vaporized component of the droplet D to a gas while maintaining its non-boiling state. A certain second heat quantity q2 is required. That is, in order to evaporate a desired amount of evaporation component from the droplet D, a total heat amount q (= q1 + q2) that is an added value of the first heat amount q1 and the second heat amount q2 is required. As described above, when the desired amount of evaporation component is raised to the target temperature in a short time, a method of irradiating the droplet D with light in the visible region corresponding to the first amount of heat q1 is available. It is effective. In the case where a desired amount of evaporation component is evaporated within a limited time while suppressing the bumping of the droplet D, light in the near infrared region or infrared region corresponding to the second heat quantity q2 is liquid. A method of irradiating the droplet D is effective.

The amount of heat can be estimated by calculation using the properties of the conductive ink Ik, the drive voltage COM applied to the piezoelectric element PZ, and the volume of the droplet D, and can be directly measured based on various experiments. Therefore, it can also be determined. For example, when the first heat quantity q1 and the second heat quantity q2 are estimated by the above-described calculation, the molar fraction of the evaporated component and the conductive fine particles obtained from the properties of the conductive ink Ik, and the evaporation component and the conductive fine particle This can be performed based on the specific heat capacity, the weight W of the droplet D obtained based on the driving voltage, and the temperature of the droplet D at the time of ejection. Among the evaporation components evaporated from the minute droplets D as described above, those that diffuse to a distance far enough from the surface of the droplet D and those that remain on the target path TL and remain on the path. Some increase the partial pressure. For this reason, the evaporation amount of the droplets at each temperature increases as the concentration of the evaporation component remaining in the target path TL decreases, and conversely decreases as the concentration of the evaporation component in the target path TL increases. Therefore, the differential equation related to the mass balance of the droplet using the mass transfer flux of the evaporated component based on the density of the evaporated component on the droplet surface and its diffusion, etc., and the heat balance of the droplet considering the heat of vaporization of the droplet The first calorie q1 and the second calorie q2 can also be estimated by solving the differential equation relating to the above, and the equation of motion of the droplet considering the air resistance to the droplet. Further, when the first heat quantity q1 and the second heat quantity q2 are determined by the above-described experiment, light of a different heat quantity is irradiated to the droplet D while imaging the droplet D in flight with a high-speed camera. The first heat quantity q1 and the second heat quantity q2 can also be obtained by directly measuring the highest heat quantity that can maintain the state in which the droplet D does not boil.

  Next, an optical system for irradiating the droplet D in flight with laser light to dry the droplet D will be described with reference to FIG. FIG. 6 is a diagram schematically showing an optical configuration of the laser irradiation unit 31 mounted on the droplet discharge device 10, and FIG. 7 schematically shows an irradiation angle of the laser beam with respect to each droplet D. It is a figure. FIG. 8 is a diagram schematically showing the absorptance of the laser light irradiated to the droplet D on the target path TL.

  As shown in FIG. 6, the laser irradiation unit 31 includes a laser emission unit 32. The laser emitting unit 32 is provided with two laser light sources 32A and 32B that emit laser beams having different wavelengths. The laser light source 32A is a device that emits a first basic laser beam Le1 having a wavelength λ1 that has a relatively high absorption rate with respect to a droplet and a cross-sectional intensity distribution of a Gaussian distribution. On the other hand, the laser light source 32B is a device that emits the second basic laser light Le2 having a wavelength λ2 that has a relatively low absorptance with respect to the droplet and a cross-sectional intensity distribution having a Gaussian distribution. In FIG. 6, the high-absorption-rate laser light emitted from the laser light source 32A is indicated by a solid line, and the low-absorption-rate laser light emitted from the laser light source 32B is indicated by a broken line.

The laser light source 32A is a so-called solid-state laser, and includes a YAG (Yttrium Aluminium Garnet) laser oscillator and a harmonic unit. The YAG laser oscillator includes an yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ ) crystal to which neodymium ions (Nd ³⁺ ) are added, and generates a fundamental wave (wavelength: 1064 nm) of YAG laser light that is near infrared light. . The harmonic unit is provided with a nonlinear optical crystal, and the fundamental wave of the YAG laser light generated by the YAG laser oscillator is passed through the nonlinear optical crystal so that the second harmonic of the YAG laser light that is visible light is transmitted. Convert to wave (SHG: Second harmonic generation, wavelength: 532 nm). The laser light source 32A having such a configuration makes the first basic laser beam Le1 having a visible region wavelength λ1 = 532 nm (see FIG. 2) having a relatively high absorption rate for the conductive ink Ik incident on the collimating lens 33A. The collimating lens 33A is a plano-convex lens having a predetermined curvature on the exit surface side, and converts the light beam of the first basic laser light Le1 emitted from the laser light source 32A into parallel light parallel to the optical axis. The light enters the half mirror 34A. The half mirror 34A splits the first basic laser beam Le1 emitted from the collimator lens 33A into a high-absorption-rate laser beam Lha and a high-absorption-rate laser beam Lhb, which are a pair of laser beams having the same energy. The high absorptivity laser beam Lha and the high absorptivity laser beam Lhb are reflected by the reflection mirrors 35 and 36 and the reflection mirror 37, respectively, and enter the first laser molding unit 45a and the second laser molding unit 45b.

  The laser light source 32B is a solid-state laser similar to the laser light source 32A and includes a YAG laser oscillator. The laser light source 32B makes the second basic laser beam Le2 having a wavelength λ2 = 1064 nm (see FIG. 2) having a relatively low absorption rate for the conductive ink Ik incident on the collimator lens 33B. The collimator lens 33B converts the light beam of the second basic laser light Le2 emitted from the laser light source 32B into parallel light parallel to the optical axis and makes it incident on the half mirror 34B. The half mirror 34B divides the second basic laser beam Le2 emitted from the collimator lens 33B into a low absorption rate laser beam Lla and a low absorption rate laser beam Llb, which are a pair of laser beams having the same energy. The low absorptance laser beam Lla and the low absorptance laser beam Llb are reflected by the reflection mirrors 38, 39, and 40 and the reflection mirrors 41 and 42, respectively, and are incident on the first laser shaping portion 45a and the second laser shaping portion 45b. To do.

  The first laser shaping unit 45a includes a cylindrical lens 46a disposed on the optical path of the high absorptance laser light Lha, a cylindrical lens 47a disposed on the optical path of the low absorptance laser light Lla, and a cold mirror 48a. , DOE (Differential Optical Element: diffractive optical element) 49a. The second laser shaping unit 45b includes a cylindrical lens 46b disposed on the optical path of the high absorptance laser light Lhb, a cylindrical lens 47b disposed on the optical path of the low absorptance laser light Llb, and a cold mirror 48b. , DOE49b.

  The cylindrical lenses 46a and 46b are lenses each having an exit surface having a curvature only in the short direction, and the cross sections of the high absorptance laser beams Lha and Lhb converted into parallel light by the collimating lens 33A are the nozzles described above. It converts into the rectangular shape extended along the formation surface 21a. The cylindrical lenses 46a and 46b convert the Z-direction components of the respective high absorptance laser beams Lha and Lhb from the corresponding reflecting mirrors, and the beam lengths in the Z direction of the respective high absorptance laser beams Lha and Lhb are formed by nozzles. A cross section is formed so as to have a temperature rising distance L1 from the surface 21a. That is, the cylindrical lenses 46a and 46b are arranged in a temperature rising area A1 that is an area on the nozzle N side with respect to the reference position DP that is separated from the nozzle forming surface 21a by the temperature rising distance L1 on the target path TL as shown in FIG. Each of the laser beams is shaped such that the high-absorption laser beams Lha and Lhb having the wavelength λ1 having a high absorption rate are irradiated to the droplet D. The high absorptance laser beams Lha and Lhb enter the cold mirrors 48a and 48b, respectively, when their cross-sectional shapes are converted by the cylindrical lenses 46a and 46b.

  The cylindrical lenses 47a and 47b are lenses each having an exit surface having a curvature only in the short direction, and the cross sections of the low absorptance laser beams Lla and Llb converted into parallel light by the collimator lens 33B are drawn as described above. Conversion into a rectangular shape extending along the surface GSa. The cylindrical lenses 47a and 47b convert the Z-direction components of the low absorptance laser beams Lla and Llb from the corresponding reflecting mirrors, and calculate the beam lengths of the low absorptance laser beams Lla and Llb in the Z direction on the drawing surface GSa. A cross section is formed so as to be an evaporation distance L2 (L2 = PG−L1) which is a distance from the reference position DP to the reference position DP. That is, the cylindrical lenses 47a and 47b have a low absorptivity with respect to the droplet D in the evaporation area A2 which is the area on the drawing surface GSa side with respect to the reference position DP on the target path TL as shown in FIG. The respective laser beams are shaped so as to be irradiated with the respective low absorptance laser beams Lla and Llb having a certain wavelength λ2. The low absorptance laser beams Lla and Llb enter the cold mirrors 48a and 48b, respectively, when their cross-sectional shapes are converted by the cylindrical lenses 47a and 47b.

The cold mirrors 48a and 48b are optical elements that reflect visible light and transmit infrared rays. That is, the cold mirrors 48a and 48b reflect the high absorptivity laser beams Lha and Lhb whose visible wavelengths are 532 nm and the low absorptance laser beams Lla and Llb whose wavelengths are near infrared rays of 1064 nm. To Penetrate. The cold mirrors 48a and 48b are arranged so that the traveling directions of these reflected light and transmitted light are equal. With such an optical configuration, a high absorption rate laser beam that irradiates the temperature rising region A1 from the nozzle formation surface 21a to the reference position DP and a low absorption rate that irradiates the evaporation region A2 from the reference position DP to the drawing surface GSa. The combined laser beams Le3a and Le3b are formed respectively.

  The DOEs 49a and 49b are optical elements that change the cross-sectional intensity distribution of the laser beams constituting the combined laser beams Le3a and Le3b formed by the cold mirrors 48a and 48b, respectively. It is composed of a high absorption part for shaping the intensity distribution of Lhb and a low absorption part for shaping the intensity distribution of the low-absorption-rate laser beams Lla and Llb. The DOEs 49a and 49b convert the intensity distribution of each laser beam in the target path TL from a Gaussian distribution to a flat top hat type cross-sectional intensity distribution (hereinafter referred to as a top hat type distribution) and irradiate the flight space. To do. In addition, the flat intensity distribution which is the top hat type distribution described above is a distribution in which the difference between the maximum intensity and the average intensity and the difference between the minimum intensity and the average intensity are within ± 5% of the average intensity, respectively. It is. Such flatness can be selected as appropriate according to the accuracy of the landing position of the droplet D and the accuracy of the landing diameter, which are the design rules for the drawing pattern.

  The DOEs 49a and 49b are predetermined with respect to the arrangement direction of the nozzles N (the one-dot chain line direction shown in FIG. 6) so as to irradiate the droplets D discharged from all the nozzles N with the synthetic laser beams Le3a and Le3b. Irradiation is performed from a direction inclined in the horizontal direction by an inclination angle θ (θ: 0 ° <θ ≦ 90 °). As shown in FIG. 7, the inclination angle θ is selected within a range satisfying sin θ ≧ 2r / Dx, for example, when the diameter of the droplet D is 2r. If the inclination angle θ satisfies such a condition, even when the synthetic laser beams Le3a and Le3b are irradiated to the droplets D from the nozzles N ejected at the same timing, they are relatively close to the DOE. The combined laser beams Le3a and Le3b are not blocked by the droplet D that is relatively far from the DOE. Therefore, the synthetic laser beams Le3a and Le3b can be evenly irradiated to all the droplets D ejected simultaneously from the ejection head 15. In addition, when the inclination angle θ satisfies sin θ = 2r / Dx, there is no gap in the laser light irradiation direction with the droplet D ejected from the adjacent nozzle N, and therefore the droplet D is irradiated. Laser light that passes through the flight space without being transmitted can be minimized, and the utilization efficiency of the laser light can be improved. Further, even if the laser light satisfies sin θ> 2r / Dx, the laser light is divided so as to correspond to the flight paths of the droplets D ejected from the nozzles N by the DOEs 49a and 49b. Laser light that passes through the space can be minimized, and utilization efficiency of the laser light can be improved.

  Energy (total energy E) corresponding to the sum of the energy received from the combined laser beam Le3a and the energy received from the combined laser beam Le3b is given to the droplet D in accordance with the irradiation mode of the pair of combined laser beams Le3a and Le3b. In the present embodiment, the total energy E is configured to be equal to the total heat quantity q described above. In the laser irradiation unit 31, the energy E1 received by the droplet D in the temperature rising region A1 corresponds to the first heat amount q1, and the energy E2 received by the droplet D in the evaporation region A2 corresponds to the second heat amount q2. It is configured as follows.

Here, the reference position DP for partitioning the temperature raising area A1 and the evaporation area A2 can be set as follows, for example. First, in order to set the heating intensity P1 and range on the target course TL of the heated region A1, based on the initial velocity v ₀ of the platen gap PG and the droplet D, lands from being ejected droplet D The total flight period t (= PG / v ₀ ) is obtained. Next, assuming that the target temperature in accordance with a predetermined drawing pattern design rule request is the boiling point of the aqueous component that is the main component of the evaporation component, the range of the temperature increase region A1 on the target path TL is the initial speed v ₀ . Based on the first flight period t1, a range from the nozzle formation surface 21a to the temperature rising distance L1 (= v ₀ × t1) is set. Further, by using the temperature rising distance L1 and the droplet diameter 2r, the light receiving cross-sectional area of the droplet D in the temperature rising region A1 is obtained as L1 × 2r. The temperature rise intensity P1 in the temperature rise region A1 is such that the energy E1 corresponding to the first heat quantity q1 described above is received by the light receiving cross section, the absorption coefficient α1 corresponding to the wavelength λ1, the first flight period t1, The temperature rise distance L1 and the diameter 2r of the droplet D are set based on the formula (1).

P1 × α1 = E1 / ((L1 × 2r) × t1) (1)
When the temperature rise intensity P1 becomes excessively high, the light pressure of the laser light acts excessively on the droplet D, and the phenomenon that the droplet D deviates from the target path TL, so-called flight bending. May occur. In addition, when the first flight period t1 is excessively short or the size of the droplet D is excessively large, the energy of the laser beam absorbed near the surface of the droplet D is transferred to the center of the droplet D. It may not be able to diffuse sufficiently. Therefore, through various experiments and computer simulations carried out in advance, the data related to the above-mentioned flight bending and the intensity range causing inadequate thermal diffusion are acquired as appropriate intensity data, and the temperature rise intensity P1 as the above calculation result is the appropriate It may be a mode for determining whether or not it is within the range of the intensity data. When the temperature rise intensity P1 is out of the above data range, the design rule is reviewed and the first flight period t1 is changed so that the temperature rise intensity P1 falls within an appropriate range. It may be.

  When the temperature increase intensity P1 and the range of the temperature increase area A1 are set in this way, the range and the evaporation intensity P2 of the evaporation area A2 on the target path TL are then set. More specifically, the range of the evaporation region A2 on the target path TL is set to the evaporation distance L2 (= PG−L1) from the drawing surface GSa by setting the range of the temperature increase region A1. The second flight period t2 (t2 = t−t1), which is the flight period of the droplet D in the evaporation region A2, is set based on the total flight period t and the first flight period t1. Further, by using the evaporation distance L2 and the droplet diameter 2r, the light receiving cross-sectional area of the droplet D in the temperature rising region A1 is obtained as L1 × 2r. The evaporation intensity P2 in the evaporation region A2 includes an absorption coefficient α2 (<α1) corresponding to the wavelength λ2 and the second flight period t2 in order to receive the energy E2 corresponding to the second heat quantity q2 described above at the light receiving cross-sectional area. Based on the equation (2), the evaporation distance L2 and the diameter 2r of the droplet D are set.

P2 × α2 = E2 / ((L2 × 2r) × t2) (2)
Here, when the evaporation component evaporates from the droplet D in flight, a reaction force against the kinetic force accompanying the evaporation acts on the droplet D. Therefore, if the reaction force acts in the direction from the higher evaporation rate to the lower evaporation rate and the evaporation rate is not symmetrical about the discharge direction of the droplet D, the reaction force against the kinetic force is applied. The flying bending of the droplet D is induced by the force, and the landing position is displaced. Therefore, the temperature rise intensity P1 and the evaporation intensity P2 set as described above are equally divided into the respective laser beams constituting the combined laser beams Le3a and Le3b, so that the evaporation rate of the droplets D takes the ejection direction as an axis. To make it symmetrical. By doing so, the reaction force against the kinetic force accompanying the evaporation of the evaporation component cancels out, so that the flying curvature of the droplet D is less likely to occur, and the displacement of the landing position can be suppressed.

The droplet D flying in the temperature rising region A1 set as described above is irradiated with laser light having a wavelength λ1 having a relatively high absorption rate, so that the temperature quickly rises to, for example, the boiling point of the evaporation component. It will be warmed. Therefore, in the flight period of the droplet D, such a temperature increase region A1 is formed near the nozzle N, so that the period in which the droplet D is near the boiling point can be lengthened. In addition, since the water-based component, which is a component having a relatively high heat of vaporization among the vaporized components, is preferentially heated in advance, the drying speed of the droplet D itself can be effectively accelerated. . When the laser beam is irradiated to the minute droplet D as described above, even if the energy of the laser beam is absorbed near the surface of the droplet D in the temperature rising region A1, the droplet is absorbed by the absorbed energy. The temperature of the surface rises, and the heat near the surface diffuses to the center of the droplet D. As a result, the temperature of the entire droplet D increases.

  In addition, the droplet D in the evaporation region A2 is maintained at a temperature high enough to maintain the temperature of the droplet D without boiling, for example, the boiling point of the evaporation component, so that the energy of the laser beam absorbed near the surface Are sequentially converted into energy for vaporizing the evaporation component, and an evaporation component having an evaporation amount corresponding to the energy supplied by the laser beam evaporates from the surface of the droplet D. Further, in the evaporation region A2, since the laser beam having the wavelength λ2 having a relatively low absorption rate is irradiated, the evaporation component is evaporated while suppressing supply of excessive energy to the droplet D. be able to. Further, in the evaporation region A2, since the laser beam has a low absorption rate, the laser beam penetrates into the inside of the droplet D, and the energy from the laser beam can be absorbed by the entire droplet D, so that the absorption is high. It is possible to suppress bump formation near the surface of the droplet D and the formation of a skin layer made of conductive fine particles deposited on the surface of the droplet D, as in the case of irradiation with a laser beam with a rate of about 100%. Here, when the droplet becomes smaller as the evaporation component evaporates, it becomes more susceptible to the influence of the laser beam, and thus flight bending is likely to occur. However, in the evaporation region A2, by irradiating the evaporation region A2 with a laser beam having a wavelength λ2 having a relatively low absorptance, even when the droplet D becomes smaller, the evaporation region A2 is less affected by the laser beam. Also, flight bends can be suppressed. As a result, a stable evaporation state can be maintained while suppressing bumping of the droplet D, and the drying efficiency of the droplet D can be improved by the amount that the period in the vicinity of the boiling point can be lengthened.

  In addition, according to the irradiation mode of the synthetic laser beams Le3a and Le3b described above, the laser beam having the wavelength λ1 is irradiated to the droplet D that is flying in the temperature rising region A1 with reference to the reference position DP of the target path TL. Then, the laser beam having the wavelength λ2 is irradiated to the droplet D that is flying in the evaporation region A2. That is, during irradiation of each laser beam, the laser beam having each wavelength is reliably irradiated to the droplet D even when the droplet D is ejected at any ejection cycle. Therefore, the time restriction related to the discharge period of the droplet D is eased, and the degree of freedom related to the discharge period of the droplet D can be improved. In addition, since it is possible to use a mode in which the laser light of each wavelength is irradiated toward the target path TL at the same timing, or can continue to be irradiated to the target path TL, the degree of freedom related to the irradiation timing of each laser light Can be extended.

  On the other hand, the maximum amount of evaporation per unit time in the droplet D naturally increases as the temperature of the droplet D increases. In addition to this, the lower the concentration of the evaporation component remaining in the target path TL, the higher the concentration, and the lower the concentration of the evaporation component in the target path TL, the lower the concentration. Therefore, when the evaporated component evaporated from the preceding droplet D is not sufficiently diffused and remains in the target path TL, the laser beam having the same energy as that of the preceding droplet D is applied to the subsequent droplet D. However, the amount of evaporation decreases, and the energy that should be converted into the heat of vaporization is accumulated in the subsequent droplet D, which may induce bumping of the droplet D. is there. In the present embodiment, by performing various computer simulations and experiments related to the diffusion of the evaporation component, a period during which the evaporation component evaporated from the droplet D is sufficiently diffused from the target path TL is acquired, and the period (for example, 1 millisecond) is adopted as the discharge interval, that is, the discharge cycle is set to 1 kHz. According to such a configuration, since the concentration of the evaporated component in the target path TL becomes the same every time the droplet D is discharged, the drying efficiency of the subsequent droplet D due to the evaporated component evaporated from the preceding droplet D is reduced. Can also be avoided.

Next, a pattern forming method for forming a pattern using the droplet discharge device 10 configured as described above will be described below.
First, the stage 12 and the carriage 16 of the droplet discharge device 10 are driven to start scanning the green sheet GS so that each lattice point T of the drawing surface GSa crosses the target path TL. Next, by driving the laser irradiation unit 31 of the droplet discharge device 10, the temperature rising region A1 that is the region on the nozzle N side with respect to the reference position DP and the evaporation that is the region on the drawing surface GSa side with respect to the reference position DP. The target route TL is partitioned into the area A2. That is, the temperature rising region A1 is irradiated with a high absorption rate laser beam having a wavelength λ1 having a relatively high absorption rate with respect to the droplet D, and a low absorption rate with a wavelength λ2 having a relatively low absorption rate with respect to the droplet D. Laser light is irradiated to the evaporation region A2. Then, by driving the discharge head 15 of the droplet discharge device 10, the droplet D is discharged from each nozzle N.

  At this time, the droplet D flying in the temperature rising region A1 is irradiated with laser light having a wavelength λ1 having a relatively high absorptance. The temperature of the droplet D can be quickly raised to the boiling point of the droplet D. Therefore, in the flight period of the droplet D, the period in which the droplet D is in the vicinity of the boiling point can be lengthened. The droplet D that has reached the reference position DP subsequently flies in the evaporation region A2 from the reference position DP to the drawing surface GSa. Here, since the temperature of the droplet D is high enough to maintain a state in which it does not boil, for example, the boiling point of the evaporation component, the energy of the laser light absorbed near the surface becomes energy for vaporizing the evaporation component. By sequentially converting, an evaporation component having an evaporation amount corresponding to the energy supplied by the laser light evaporates from the surface of the droplet D. Further, in the evaporation region A2, since the laser beam having the wavelength λ2 having a relatively low absorption rate is irradiated, the evaporation component is evaporated while suppressing supply of excessive energy to the droplet D. be able to.

  As a result, while the droplet D in a state where the bumping is suppressed is maintained in a stable evaporation state, the droplet D lands on the lattice point T with high drying efficiency by the length of the period near the boiling point. Become. Therefore, the pattern can be formed by landing the droplet D on the desired lattice point T without causing spreading due to insufficient drying or disappearance due to bumping.

As described above, according to the droplet discharge device 10 of the first embodiment, the following effects can be obtained.
(1) In the temperature increase region A1 of the first embodiment, the droplet D ejected from the nozzle N receives the laser beam having the wavelength λ1 having a relatively high absorption rate immediately after the ejection, so that the temperature reaches the target temperature. The temperature can be increased efficiently. Therefore, since more flight periods can be assigned to the evaporation region A2 for evaporating the evaporation component of the droplet D during the flight period of the droplet D, the drying efficiency of the droplet D can be improved.

  (2) According to the laser light irradiation mode of the first embodiment, each laser light irradiation region is spatially partitioned in the target path TL. Even when the droplet D is ejected at any ejection cycle, the laser beam having a relatively high absorption rate is irradiated to the droplet D prior to the laser beam having a relatively low absorption rate. Therefore, since the time restrictions related to the discharge period and discharge period of the droplet D, the irradiation timing and irradiation period of the laser beam are eliminated, the degree of freedom related to the discharge period of the droplet D can be improved.

  (3) In the evaporation region A2 of the first embodiment, a laser beam having a wavelength λ2 having a relatively low absorptance is irradiated so that the droplet D that is the target temperature does not receive energy exceeding the heat of vaporization. For this reason, bumping of the droplet D can be effectively prevented.

  (4) In the target path TL of the first embodiment, the total energy E supplied to the droplets D from the combined laser beams Le3a and Le3b is the total amount of heat q required to evaporate a desired amount of evaporation components. Therefore, the discharged droplets D can be landed in a desired dry state.

(5) According to the first embodiment, since the evaporation rate of the droplet D in flight is symmetric with respect to the ejection direction, the movement acting on the droplet D due to evaporation of the evaporation component of the droplet D. The reaction force against the force is countered. In other words, flight bending due to evaporation of the evaporation component is less likely to occur in the droplet D, and displacement of the landing position of the droplet D can also be suppressed.

  (6) According to the first embodiment, the combined laser beams Le3a and Le3b are irradiated at an inclination angle θ with respect to the arrangement direction of the nozzles N. As a result, the combined laser beams Le3a and Le3b can be applied to the droplets D ejected simultaneously from all the nozzles N of the ejection head 15. Therefore, it is possible to improve the drying efficiency for all the droplets D ejected at the same timing. In addition, when the inclination angle θ satisfies sin θ = 2r / Dx, there is no gap between the liquid droplets D ejected from the nozzle N adjacent to the laser light irradiation direction, so that all liquids When the laser beam is irradiated onto the droplet D, the horizontal irradiation range can be reduced, and the utilization efficiency of the laser beam can be improved.

(7) According to the first embodiment, the first laser shaping portion 45a and the second laser shaping portion 45b are arranged so as to be closer to the target path TL than the half mirror 34. The diffraction of the combined laser beams Le3a and Le3b from when the light is converted to when the droplet D is irradiated can be suppressed. That is, the intensity distribution in the target route TL can be realized with high accuracy.
(Second Embodiment)
Hereinafter, a second embodiment in which the pattern forming apparatus of the present invention is embodied as a droplet discharge apparatus will be described with reference to FIGS. In the second embodiment, the optical configuration of the droplet discharge device 10, the laser light irradiation mode, and the like are changed. Therefore, the changes will be described in detail below. FIG. 9 is a diagram schematically illustrating an optical configuration of a laser irradiation unit of the droplet discharge device according to the second embodiment.

  As shown in FIG. 9, the laser irradiation unit 51 includes a laser emitting unit 32, a collimating lens 33, a half mirror 34 as a branching unit, reflection mirrors 55, 56, 57, 58 and 59, and a first laser forming unit. 65a and a second laser forming portion 65b.

  The laser emitting unit 32 is provided with a laser light source 32A that emits laser light having a wavelength λ1 and a laser light source 32B that emits laser light having a wavelength λ2. From the laser emitting unit 32 of the second embodiment, laser light of one of the wavelengths is selectively emitted on the time axis, and in the following, when the wavelength is not distinguished in the laser light emitted from the laser emitting unit 32 This will be described simply as the laser beam Le4. The laser beam Le4 emitted from the laser emitting unit 32 is divided into two laser beams Le4a and Le4b having the same energy by the half mirror 34 via the collimator lens 33.

  Each of the reflection mirrors 55 and 56 is a plane mirror having a reflection surface capable of reflecting laser beams having two wavelengths λ1 and λ2, and makes the laser beam Le4a, which is the reflection beam, incident on the first laser forming portion 65a. Each of the reflection mirrors 57 to 59 is a plane mirror having a reflection surface capable of reflecting the laser beams having the two wavelengths λ1 and λ2, and makes the laser beam Le4b, which is the reflection beam, incident on the second laser forming portion 65b. .

The first laser shaping unit 65a includes a cylindrical lens 61a and a DOE 62a on the optical path of the laser beam Le4a. The second laser shaping unit 65b includes a cylindrical lens 61b and a DOE 62b on the optical path of the laser beam Le4b. The cylindrical lenses 61a and 62b are lenses each having an exit surface having a curvature only in the short direction, and the cross sections of the laser beams Le4a and Le4b converted into parallel light by the collimating lens 33 are referred to as the nozzle forming surface 21a. Convert to a rectangular shape extending along. The laser beams Le4a and Le4b incident on the cylindrical lenses 61a and 61b have a predetermined width in the Z direction. Therefore, when the laser light is irradiated to the flight space without being molded by the cylindrical lenses 61a and 61b, the end in the Z direction of the laser light is the ejection head 15, the green sheet GS, the stage 12, and the like. And the energy of the laser beams Le4a and Le4b is partially lost. The cylindrical lenses 61a and 61b convert the Z-direction components of the laser beams Le4a and Le4b from the corresponding reflecting mirrors, respectively, and change the beam length in the Z-direction of the laser beams Le4a and Le4b to the platen gap PG (in this embodiment, The cross-sectional shape is formed to be equal to 1000 μm). Thereby, the laser beams Le4a and Le4b can be guided to the target path TL of the droplet D while suppressing the energy loss of the laser beams Le4a and Le4b.

  The DOEs 62a and 62b convert the sectional intensity distributions of the laser beams Le4a and Le4b formed by the cylindrical lenses 61a and 62a, respectively, from a Gaussian distribution to a top hat type distribution and irradiate the flight space.

  Next, the electrical configuration of the droplet discharge device 10 configured as described above will be described with reference to FIG. FIG. 10 is a block circuit diagram showing the electrical configuration of the droplet discharge device, and FIG. 11 is a block circuit diagram showing the electrical configuration of the head drive circuit.

  In FIG. 10, the control device 80 of the droplet discharge device 10 includes a control unit 81 composed of a CPU or the like, a ROM 82, a RAM 83, and the like, and the stage 12 and the carriage according to various data and various control programs stored in the ROM 82 and RAM 83. 16 transport processing, droplet ejection processing of the ejection head 15, laser light switching processing of the laser emitting unit 32, and the like. The control device 80 also includes an oscillation circuit 84 that generates a clock signal, a drive waveform generation circuit 85 that generates a drive waveform signal, an external I / F 86 that receives various signals, and an internal I that transmits and receives various signals. / F87.

  The control device 80 is electrically connected to the input / output device 88 via the external I / F 86. The control device 80 is electrically connected to a carriage motor drive circuit 89, a stage motor drive circuit 90, a head drive circuit 91, and a laser light source drive circuit 92 via an internal I / F 87.

  The input / output device 88 is an external computer having, for example, a CPU, RAM, ROM, hard disk, liquid crystal display, and the like. The input / output device 88 includes information on the position coordinates of the grid point T of the dot pattern grid DL with respect to the drawing surface GSa, information on the volume of the droplet D, information on the properties of the conductive ink Ik, the first and second flight periods t1, Information relating to t2, information relating to the intensity of each laser beam, and the like are input to the control device 80 as drawing information Ia. The control device 80 receives the drawing information Ia from the input / output device 88 and stores the drawing information Ia in the RAM 83.

  The oscillation circuit 84 generates a clock signal for synchronizing various data and various drive signals. The oscillation circuit 84 generates a transfer clock CLK for serially transferring various data, for example. The oscillation circuit 84 generates a timing signal LAT for parallel conversion of various data to be serially transferred in the droplet D ejection cycle. The oscillation circuit 84 generates a switching signal CHA for switching the laser light source every time the first flight period t1 elapses after generating the timing signal LAT. Note that the timing signal LAT of the second embodiment is generated at a cycle of the total flight period t (= t1 + t2).

The drive waveform generation circuit 85 stores waveform data for generating the drive voltage COM in association with a predetermined address. The control unit 81 reads out waveform data for obtaining a droplet D having a predetermined volume based on the information regarding the volume of the droplet D in the drawing information Ia. The drive waveform generation circuit 85 latches the waveform data read by the control unit 81 for each clock signal of the ejection cycle, converts it into an analog signal, amplifies the analog signal, and generates the drive voltage COM.

  When a corresponding drive control signal is input from the control device 80, the carriage motor drive circuit 89 rotates the carriage motor CM for moving the carriage 16 forward or backward in response to the drive control signal. A carriage encoder CE is connected to the carriage motor drive circuit 89, and a detection signal is input from the carriage encoder CE. The carriage motor drive circuit 89 generates a signal related to the movement direction and movement amount of the carriage 16 relative to the drawing surface GSa, that is, a signal related to the movement direction and movement amount of the nozzle N, based on the detection signal from the carriage encoder CE, and sends it to the control device 80. Output.

  When the corresponding drive control signal is input from the control device 80, the stage motor drive circuit 90 rotates the stage motor SM for moving the stage 12 forward or backward in response to the drive control signal. A stage encoder SE is connected to the stage motor drive circuit 90, and a detection signal is input from the stage encoder SE. Based on the detection signal from the stage encoder SE, the stage motor drive circuit 60 generates a signal related to the moving direction and moving amount of the stage 12, that is, a signal related to the moving direction and moving amount of the lattice point T, which is the target position, and performs control. Output to the device 80.

  The control unit 81 generates dot pattern data based on the drawing information Ia stored in the RAM 83. The drawing surface GSa is virtually divided into the dot pattern lattice DL as described above, and the selection of whether or not to discharge the droplets D is defined for each lattice point T. The dot pattern data is data that associates whether or not each droplet D is ejected to each lattice point T.

  When the dot pattern data is generated, the control unit 81 generates serial data synchronized with the transfer clock CLK using the dot pattern data, and serially transfers the serial data to the head drive circuit 91 via the internal I / F 87. To do. In the present embodiment, serial data generated using dot pattern data is referred to as serial pattern data SI. The serial pattern data SI is data for associating the ejection and non-ejection of the droplet D defined based on the dot pattern data with each piezoelectric element PZ, and is generated in the ejection cycle of the droplet D.

  Based on a signal related to the moving direction and moving amount of the stage 12 from the stage encoder SE, that is, a signal related to the moving direction and moving amount of the grid point T, which is the target position, the control unit 81 sets each grid point T directly below the nozzle N. The timing signal LAT is generated when each grid point T is located immediately below the nozzle N, and is output to the head drive circuit 91.

  As shown in FIG. 11, the head drive circuit 91 includes a shift register 93, a control signal generation unit 94, a level shifter 95, and a piezoelectric element switch 96. The shift register 93 receives the transfer clock CLK from the control device 80 and sequentially shifts the serial pattern data SI. The shift register 93 stores the number of nozzles N, that is, serial pattern data SI including i bit values.

The control signal generation unit 94 receives the timing signal LAT from the control device 80 and latches the serial pattern data SI stored in the shift register 93. The control signal generation unit 94 performs serial / parallel conversion on the serial pattern data SI to be latched, generates i-bit parallel data corresponding to each nozzle N, and outputs the parallel data to the level shifter 95. In the present embodiment, the parallel data output from the control signal generation unit 94 is referred to as parallel pattern data PI. The level shifter 95 boosts the parallel pattern data PI from the control signal generation unit 94 to the drive voltage level of the piezoelectric element switch 96, and generates i open / close signals associated with each piezoelectric element PZ.

  The piezoelectric element switch 96 has i switch elements corresponding to each piezoelectric element PZ, and the drive voltage COM from the control device 80 is input to the input end of each switch element, and the output of each switch element. A corresponding piezoelectric element PZ is connected to each end. Each switch element outputs a drive voltage COM to the corresponding piezoelectric element PZ in accordance with an open / close signal associated with the corresponding piezoelectric element PZ. When the lattice point T is located immediately below the nozzle N, the head drive circuit 91 outputs the drive voltage COM to the corresponding piezoelectric element PZ. As a result, the head drive circuit 91 discharges the droplet D toward the lattice point T selected based on the dot pattern data. That is, the head driving circuit 91 discharges the droplet D from the corresponding nozzle N every time the timing signal LAT is input.

  Here, FIGS. 12A and 12B are diagrams schematically showing the laser light irradiation mode in the second embodiment. As shown in FIG. 12, the laser irradiation unit 51 of the second embodiment is also shown. In FIG. 2, since the Z direction components in the cross section of the laser light having the wavelengths λ1 and λ2 are both equal to the platen gap PG, each laser light is irradiated over the entire flight space of the droplet D. Therefore, in the second embodiment, a laser beam having a high absorptance of wavelength λ1 is applied to the flying droplet D in the temperature rising region A1, and the evaporation region A2 is applied to the flying droplet D in the flight region A1. Switching control of the laser beam irradiated to the target path TL is performed so as to irradiate the laser beam with the wavelength λ2 having a relatively low absorption rate.

  More specifically, a laser light source driving circuit 92 is connected to the control device 80 as a laser control unit via an internal I / F 87. The control unit 81 outputs to the laser light source driving circuit 92 a timing signal LAT that is a discharge cycle of the droplet D and a switching signal CHA that is generated with a delay of the first flight period t1 from the timing signal LAT.

  When the timing signal LAT is input, the laser light source driving circuit 92 drives the laser light source 32A and irradiates the target path TL with the laser light having the wavelength λ1 as shown in FIG. When the switching signal CHA is input, the laser light source 32A is stopped and the laser light source 32B is driven to irradiate the target path TL with the laser light having the wavelength λ2, as shown in FIG. The laser light source driving circuit 92 stops the laser light source 32B when the timing signal LAT is newly input or when a preset time (≧ t2) has elapsed. With such a configuration, the droplet D positioned in the temperature rising region A1 can be irradiated with laser light having the wavelength λ1, and the droplet D positioned in the evaporation region A2 can be irradiated with laser light having the wavelength λ2. . As a result, the laser beam having the wavelength λ1 is irradiated only when the droplet D is positioned in the temperature rising region A1, and the laser beam having the wavelength λ2 is irradiated only when the droplet D is positioned in the evaporation region A2. That is, the laser beam can be switched according to the flight position of the droplet D, and the utilization efficiency of each laser beam can be improved by the amount not irradiated with one laser beam.

  Next, a pattern forming method for forming a pattern using the droplet discharge device 10 configured as described above will be described below. FIG. 13 is a timing chart showing laser beam switching processing in the droplet discharge device 10 configured as described above.

When new drawing information Ia is input to the control device 80 and a drawing start operation is performed, first, dot pattern data is generated, the carriage 16 (ejection head 15) is placed at a predetermined position, and the stage 12 is moved. Be started. The controller 81 generates serial pattern data SI based on the dot pattern data and serially transfers it to the shift register 93 of the head drive circuit 91. The control unit 81 grasps the amount of movement of the stage 12 based on the detection signal from the stage encoder SE, and when it is determined that the lattice point T is located immediately below the nozzle N, the oscillation circuit 84 uses the timing signal LAT. Is output to the head drive circuit 91 and the laser light source drive circuit 92.

  In the head drive circuit 91 to which the timing signal LAT is input, the control signal generation unit 94 latches the serial pattern data SI stored in the shift register 93, generates parallel pattern data PI, and outputs it to the level shifter 95. The level shifter 95 boosts the parallel pattern data PI to the drive voltage level of the piezoelectric element switch 96, and outputs an open / close signal corresponding to each piezoelectric element PZ. The piezoelectric element switch 96 supplies the driving voltage COM to the corresponding piezoelectric element PZ in accordance with the input opening / closing signal, and discharges the droplet D from the nozzle N. On the other hand, in the laser light source driving circuit 92 to which the timing signal LAT is input, the laser light source 32A is driven, and the target path of the droplet D having the wavelength λ1 having a relatively high absorption rate as shown in FIG. Irradiated on TL.

  Therefore, the droplet D positioned in the temperature rising region A1 that is the region on the nozzle N side with respect to the reference position DP is irradiated with laser light having a wavelength λ1 that has a high absorption rate. That is, the temperature of the droplet D immediately after ejection can be quickly raised to, for example, the boiling point of the evaporation component. Therefore, in the flight period of the droplet D, the period in which the droplet D is in the vicinity of the same boiling point. Can be lengthened.

  The droplet D ejected by generating the timing signal LAT reaches the reference position DP after the first flight period t1. The controller 81 generates a switching signal CHA for switching the laser light source by the oscillation circuit 84 and outputs it to the laser light source driving circuit 92 when the first flight period t1 has elapsed since the generation of the timing signal LAT. The laser light source driving circuit 92 to which the switching signal CHA is input stops driving the laser light source 32A, and drives the laser light source 32B to absorb relatively on the target path TL as shown in FIG. A laser beam having a wavelength λ2 having a low rate is irradiated.

  Therefore, a laser beam having a wavelength λ2 having a low absorption rate is irradiated to the droplet D positioned in the evaporation region A2, which is a region closer to the drawing surface GSa than the reference position DP. Since the temperature of the droplet D is high enough to maintain the state where it does not boil, for example, the boiling point of the evaporated component, the energy of the laser light absorbed near the surface is sequentially converted into energy for vaporizing the evaporated component. Thus, an evaporation component having an evaporation amount corresponding to the energy supplied by the laser beam evaporates from the surface of the droplet D. Further, in the evaporation region A2, since the laser beam having the wavelength λ2 having a relatively low absorption rate is irradiated, the evaporation component is evaporated while suppressing supply of excessive energy to the droplet D. be able to. As a result, a stable evaporation state can be maintained while suppressing bumping of the droplet D, and the drying efficiency of the droplet D can be improved by the amount that the period in the vicinity of the boiling point can be lengthened.

  Then, after the droplet D reaches the reference position DP, when the second flight period t2 elapses, the droplet D lands on the drawing surface GSa and the next timing signal LAT is generated to generate the head driving circuit 91 and It is output to the laser light source driving circuit 92. The head drive circuit 91 discharges a new droplet D, and the laser light source drive circuit 92 driving the laser light source 32B stops the laser light source 32B when the timing signal LAT is input, while the laser light source 32B is driven. The light source 32A is driven to irradiate the target path TL with laser light having a wavelength λ1 having a high absorption rate. In this way, by switching the laser light irradiated according to the flight position of the droplet D, the utilization efficiency of each laser light can be improved by the amount not irradiated with one laser light. Thereafter, this is repeated to form a desired pattern on the drawing surface GSa of the green sheet GS.

As described above, according to the droplet discharge device 10 of the second embodiment, the following effects can be obtained in addition to the effects (1) to (6) of the first embodiment. That is, since the laser beam irradiated to the target path TL is switched according to the flight position of the droplet D, the utilization efficiency of each laser beam can be improved by the amount not irradiated with one laser beam.

In addition, the said embodiment can also be changed and implemented as follows.
In the first and second embodiments, the example in which the temperature of the droplet D is raised to the target temperature in the temperature rising region A1 has been described. However, in the temperature rising region A1, the temperature of the droplet D is targeted. A form in which the temperature is raised to a temperature lower than the temperature may be used, and any form in which laser light having a higher absorptance than the laser light in the evaporation region A2 is irradiated may be used. In such a form, a laser beam having a relatively high absorptance is irradiated to a droplet that has just been ejected, so that the energy applied to the droplet is effectively converted into thermal energy immediately after ejection. be able to.

  In the first and second embodiments, the laser beam having a relatively high absorptance is the second harmonic of the YAG laser having the wavelength λ1 (532 nm). Further, a laser beam having a relatively low absorptance was used as a fundamental wave of a YAG laser having a wavelength λ2 (1064 nm). However, the present invention is not limited to this, and laser light having other wavelengths may be used as long as the relative height difference of the absorption rate can be set. The YAG laser is a so-called solid-state laser, but a liquid laser, a gas laser, a semiconductor laser, or the like may be used for irradiating the droplet D with laser light.

  In the first embodiment, the YAG laser fundamental wave and the second harmonic wave are synthesized by using cold mirrors 48a and 48b, which are optical elements that reflect visible light and transmit infrared light, and combine laser light Le3a. , Le3b. In the case of using other types of laser light sources as described above, an optical element capable of synthesizing two laser beams may be provided according to the wavelength of the laser beam to be used.

  -In the laser irradiation part 31 of the said 1st Embodiment, while being irradiated to the temperature rising area A1 which is the area | region of the nozzle N side rather than the reference position DP with the laser beam of wavelength (lambda) 1 which is a high absorption factor, it is a low absorption factor. The laser beam having the wavelength λ2 is applied to the evaporation region A2, which is a region closer to the drawing surface GSa than the reference position DP. Not limited to this, when irradiating the laser beam having the wavelength λ1 in the temperature rising region A1, the laser beam having the wavelength λ2 is irradiated to the entire flight space of the droplet D, and the wavelength is only applied to the temperature rising region A1. You may make it irradiate with the laser beam of (lambda) 1. That is, a mode in which the laser beams having the wavelengths λ1 and λ2 overlap in the temperature rising region A1 and the droplets D are irradiated with the laser beams may be used. At this time, the temperature rise intensity P1 of the laser beam having the wavelength λ1 may be derived in consideration of the irradiation with the laser beam having the wavelength λ2. According to this, the droplet D that is flying in the temperature rising region A1 can absorb more energy by the amount of the laser light having the wavelength λ1 overlapped with the laser light having the wavelength λ1. In the laser irradiation unit 51 of the second embodiment, the laser light source 32A that emits laser light having the wavelength λ1 is driven when the timing signal LAT is input, and the laser light source 32A is input when the switching signal CHA is input. While stopping, the laser light source 32B which emits the laser beam of wavelength λ2 was driven. That is, a laser beam having a high absorptance is emitted at the timing when the droplet D is ejected, the emission of the laser beam having a high absorptance is stopped at a timing when the flight time of the droplet passes a predetermined time, and a low absorption is achieved. An example of emitting a laser beam with a rate of 1 was described.

By changing this, when irradiating the laser beam having a high absorptance to the droplet D located in the temperature rising region A1, the laser beam having a low absorptance is continuously irradiated to the entire flight path of the droplet D. A method of emitting a laser beam having a high absorptance at the timing when the droplet D is ejected and stopping the emission of the laser beam having a high absorptance at a timing when the flying time of the droplet D elapses a predetermined time. Also good. That is, as shown in FIG. 14A, first, the laser light source 32A and the laser light source 32B are driven based on the timing signal LAT, so that the laser beam having a high absorption rate over the entire temperature raising region A1 and the entire region of the flight path. And a laser beam having a low absorption rate. Next, at the timing when the droplet D reaches the reference position DP, as shown in FIG. 14B, only the laser beam having a low absorption rate may be irradiated to the entire flight path. According to this embodiment, when the droplet D is not positioned in the temperature rising area A1, the laser light irradiation in the temperature rising area A1 and the laser light irradiation in the evaporation area A2 are performed by the amount not irradiated with the laser beam having the wavelength λ1. And can be switched smoothly. In this case, high-absorption laser light may be irradiated to the entire flight path.

  In the laser irradiation unit 31 of the first embodiment, the laser beam irradiated to the droplet D by constantly irradiating the laser beam having the wavelength λ1 to the temperature rising region A1 and the laser beam having the wavelength λ2 to the evaporation region A2 I switched spatially. On the other hand, in the laser irradiation part 51 of the said 2nd Embodiment, the laser beam irradiated to the droplet D was switched temporally by switching the laser light source to drive with the timing signal LAT and the switching signal CHA. By combining these, as shown in FIGS. 15A and 15B, the laser beam having the wavelength λ1 is irradiated to the temperature rising region A1, and the laser beam having the wavelength λ2 is irradiated to the evaporation region A2. You may make it switch the laser beam irradiated to flight space according to a flight position. According to this, the utilization efficiency of the laser beam can be improved while increasing the degree of freedom related to the ejection cycle of the droplet D.

  In the second embodiment, the laser light applied to the flight space of the droplet D is switched by inputting the switching signal CHA to the laser light source driving circuit 92. The laser light source driving circuit 92 is provided with a delay circuit that generates a driving signal obtained by delaying the timing signal LAT by the first flight period t1 when switching the laser light irradiated to the flight space. The drive circuit 92 may drive the laser light source 32A only during the first flight period t1 based on the timing signal LAT, and drive the laser light source 32B only during the second flight period t2 based on the drive signal.

  According to the first and second embodiments, the laser beam having different wavelengths is irradiated to the temperature raising area A1 and the evaporation area A2. However, the present invention is not limited to this, and if it is possible to quickly raise the temperature of the droplet D to the target temperature in the temperature raising region A1, a plurality of laser beams may be irradiated to the temperature raising region A1.

  In the laser irradiation units 31 and 51 in the first and second embodiments, the optical axis of each laser beam irradiated to the flight space of the droplet D is inclined by the inclination angle θ with respect to the arrangement direction of the nozzles N. . Not limited to this, when irradiating the droplet D with laser light of each wavelength, the optical axis of each laser light is not inclined with respect to the arrangement direction of the nozzles N, but coincides with the arrangement direction. Good. At this time, by sequentially ejecting the droplets D from the nozzles N of the ejection head 15 at different ejection timings, it is possible to irradiate all the droplets D with laser light.

  In the first and second embodiments, the ejection head 15 has one nozzle row composed of the nozzles N. Not limited to this, a plurality of nozzle rows may be formed in the ejection head 15. At this time, the tilt angle θ of the optical axis of the laser light may be appropriately changed so that the combined laser beams Le3a and Le3b and the laser beams Le4a and Le4b are irradiated to all the droplets D ejected from the nozzle N.

  According to the first and second embodiments, the cross-sectional intensity distribution of each laser beam is converted from the Gaussian distribution to the top hat type distribution by disposing the DOE on the optical path of each laser beam. However, the present invention is not limited to this, and when irradiating the droplet D with a laser beam that supplies desired energy, the intensity is within a range where bumping is suppressed in the peak region of the Gaussian distribution. DOE may be omitted and laser light with Gaussian distribution may be applied.

In addition, when ejecting a droplet D having a high content of evaporation component, the evaporation component evaporates during the flight, so that the weight and surface area of the droplet D are reduced and the flight is caused by air resistance. The speed may also decrease. In such a case, as the drawing surface GSa is approached, flight bending due to evaporation of evaporation components is likely to occur, and evaporation from the surface of the droplet D per unit time is possible due to the small surface area. The amount of the evaporated component is also gradually reduced. Therefore, if the evaporation region A2 is irradiated with a plurality of laser beams having different wavelengths and the absorption rate of the laser beam decreases as it approaches the drawing surface GSa, that is, the weight and surface area of the droplet D by evaporation of the evaporation component, Furthermore, as long as the flight speed decreases, the energy supplied to the droplet D decreases, so that the energy corresponding to the weight and surface area of the droplet D can be absorbed from the laser light. Therefore, bumping of the droplet D can be reliably prevented, flight bending due to evaporation of the evaporation component is further less likely to occur, and displacement of the landing position can be further suppressed.

  In the embodiment described above, the liquid droplet ejecting apparatus 10 that draws the metal wiring by ejecting the conductive ink Ik containing the conductive fine particles on the green sheet GS is embodied. However, the present invention is not limited to this, and may be applied to a pattern forming apparatus for other uses such as a pattern forming apparatus for drawing an insulating pattern, as long as the flying droplets are irradiated with laser light and dried.

  In the embodiment described above, the piezoelectric element driving type droplet discharge device 10 is embodied. However, the present invention is not limited to this, and from the viewpoint of ejecting droplets from the ejection head, the present invention may be embodied in a droplet ejection apparatus equipped with a resistance heating type or electrostatic drive type ejection head.

The perspective view which shows an example of the pattern formation apparatus concerning this invention. The graph which shows the wavelength dependence of the absorptivity of electroconductive ink. The perspective view which shows an ejection head. FIG. 3 is a main part cross-sectional view showing the inside of the ejection head. The schematic diagram which shows the dot pattern lattice of a green sheet. The schematic diagram which shows the optical structure in 1st Embodiment. The schematic diagram for demonstrating the relationship between a laser beam and a droplet. The schematic diagram which shows the relationship between the flight position and absorption rate of the droplet in 1st Embodiment. The schematic diagram which shows the optical structure in 2nd Embodiment. FIG. 6 is a block circuit diagram illustrating an electrical configuration of a droplet discharge device according to a second embodiment. The block circuit diagram which shows the electric constitution of the head drive circuit in 2nd Embodiment. (A), (b) The schematic diagram which showed the irradiation aspect of each laser beam in 2nd Embodiment. The timing chart which showed the switching process of the laser beam in 2nd Embodiment. (A), (b) The schematic diagram which showed the irradiation aspect of the laser beam in the example of a change. (A), (b) The schematic diagram which showed the irradiation aspect of the laser beam in the example of a change.

Explanation of symbols

λ, λ1, λ2 ... wavelength, α, α1, α2 ... absorption coefficient, θ ... tilt angle, D ... droplet, E ... total energy, N ... nozzle, q ... total heat, t ... total flight duration, T ... lattice Point, A1 ... temperature increase region, A2 ... evaporation region, CE ... carriage encoder, CM ... carriage motor, DL ... dot pattern grid, DP ... reference position, Dx ... nozzle pitch, Dy ... discharge pitch, E1 ... energy, E2 ... Energy, GS ... green sheet, Ia ... drawing information, Ik ... conductive ink, L1 ... temperature rising distance, L2 ... evaporation distance, P1 ... temperature rising intensity, P2 ... evaporation intensity, PG ... platen gap, PI ... parallel pattern data , PZ ... piezoelectric element, q1 ... first heat quantity, q2 ... second heat quantity, SE ... stage encoder, SI ... serial pattern data, SM ... stage motor, t1 ... first flight period, t2 ... first Flight period, TL ... target route, v0 ... initial speed, CHA ... switching signal, CLK ... transfer clock, COM ... drive voltage, GSa ... drawing surface, LAT ... timing signal, Le1 ... first basic laser beam, Le2 ... second basic Laser light, Lha, Lhb ... high absorption laser light, Lla, Llb ... low absorption laser light, Le3a, Le3b ... synthesis laser light, Le4, Le4a, Le4b ... laser light, 2r ... diameter, 10 ... droplet ejection device DESCRIPTION OF SYMBOLS 11 ... Base, 12 ... Stage, 13 ... Guide member, 14 ... Ink tank, 15 ... Discharge head, 16 ... Carriage, 17 ... Head substrate, 17a ... Connection terminal, 20 ... Head body, 20T ... Supply tube, 21 ... Nozzle plate, 21a ... Nozzle formation surface, 22 ... Cavity, 23 ... Vibration plate, 31 ... Laser irradiation part, 32 ... Laser emission part, 32A ... The light source, 32B ... laser light source, 33 ... collimating lens, 33A ... collimating lens, 33B ... collimating lens, 34, 34A, 34B ... half mirror, 35, 36, 37, 38, 39, 40, 41, 42 ... reflecting mirror 45a ... first laser molding part, 45b ... second laser molding part, 46a, 46b ... cylindrical lens, 47a, 47b ... cylindrical lens, 48a, 48b ... cold mirror, 49a, 49b ... DOE, 51 ... laser irradiation part, 55, 56, 57, 58, 59 ... reflection mirror, 60 ... stage motor drive circuit, 61a, 61b ... cylindrical lens, 62a, 62B ... DOE, 65a ... first laser shaping part, 65b ... second laser shaping part, 80 ... Control device, 81 ... Control unit, 82 ... ROM, 83 ... RAM, 84 ... Oscillator circuit, 8 DESCRIPTION OF SYMBOLS ... Drive waveform generation circuit, 86 ... External I / F, 87 ... Internal I / F, 88 ... I / O device, 89 ... Carriage motor drive circuit, 90 ... Stage motor drive circuit, 91 ... Head drive circuit, 92 ... Laser light source Drive circuit, 93... Shift register, 94... Control signal generation unit, 95... Level shifter, 96.

Claims (7)

A liquid droplet containing an evaporation component and a pattern forming material is ejected from a nozzle toward a drawing target, and the droplet in flight is irradiated with a laser beam to evaporate a predetermined amount of the evaporation component from the droplet. A pattern forming method for forming a pattern on the drawing object by allowing
The liquid material has different absorptance depending on the wavelength of the irradiated laser beam,
The laser beam is a plurality of laser beams having different wavelengths,
On the path connecting the landing position of the droplet on the drawing object and the nozzle, the closer to the nozzle, the greater the energy absorbed by the droplet.
The pattern forming method of irradiating the plurality of laser beams. Irradiation of the plurality of laser beams is
2. The pattern forming method according to claim 1, wherein the laser beam having a wavelength with a high absorption rate of the liquid material is irradiated in advance of the laser beam having a wavelength with a low absorption rate of the liquid material. Irradiation of the plurality of laser beams is
The laser beam having a wavelength with a high absorption rate of the liquid material is on a path connecting the landing position of the droplet on the drawing object and the nozzle, compared with the laser beam having a wavelength with a low absorption rate of the liquid material. The pattern forming method according to claim 1, wherein irradiation is performed at a position close to the nozzle. The liquid is
The pattern forming method according to any one of claims 1 to 3, wherein the pattern has a high absorptance in visible light with respect to infrared light. The evaporation component of the liquid is
An aqueous component that is a polar solvent;
An organic component that is a nonpolar solvent,
The pattern formation method according to any one of claims 1 to 4, wherein the water-based component has a higher absorptance in visible light than the organic component. Laser light having a wavelength with a high absorption rate of the liquid material raises the temperature of the droplet to a target temperature that is the highest temperature that does not boil the temperature of the droplet,
The pattern forming method according to claim 1, wherein a laser beam having a wavelength with a low absorption rate of the liquid supplies heat of vaporization to the droplet. An ejection head that ejects liquid droplets containing an evaporation component and a pattern forming material from a nozzle toward a drawing target, and a predetermined amount of the evaporation component is evaporated by irradiating the droplets in flight with laser light. A laser irradiation unit,
A pattern forming apparatus for forming a pattern by landing the droplet on the drawing object,
The liquid material has different absorptance depending on the wavelength of the irradiated laser beam,
The laser irradiation unit is
On the path connecting the landing position of the droplet on the drawing object and the nozzle, the closer to the nozzle, the greater the energy absorbed by the droplet.
The pattern forming apparatus irradiating the plurality of laser beams toward the path.

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