JP2007296426A - Pattern forming method, droplet discharge device, and circuit module - Google Patents

Abstract

Provided are a pattern forming method, a droplet discharge device, and a circuit module in which droplet drying efficiency is improved and formation failure of a pattern formed of droplets is reduced.
A reflection mirror 27 mounted on a carriage 20 guides laser light emitted from a semiconductor laser LD to a reflection position Pe as incident light Le substantially along a scanning direction. Further, the control device scans the droplet Fb landed on the pattern formation surface 4Sa in the scanning direction, and joins the droplet Fb with the preceding droplet Fb when the droplet Fb is located at the reflection position Pe. Then, the incident light Le substantially along the scanning direction is incident on the bottom outer peripheral portion of the liquid film FL composed of the joined droplets Fb on the side opposite to the scanning direction.
[Selection] Figure 6

Description

  The present invention relates to a pattern forming method, a droplet discharge device, and a circuit module.

  2. Description of the Related Art In recent years, circuit modules on which electronic components such as semiconductor elements are mounted include those having a low temperature co-fired ceramic multilayer substrate (Low Temperature Co-fired Ceramics: LTCC multilayer substrate). Since the LTCC multilayer substrate can fire the laminated green sheets at a low temperature of 900 ° C. or lower, a low melting point metal such as silver or gold can be used for the internal wiring, and the resistance of the internal wiring can be reduced.

In the manufacturing process of such an LTCC multilayer substrate, a metal paste or metal ink is used to draw a wiring pattern on each green sheet before lamination. As this drawing method, Patent Document 1 proposes a so-called ink jet method in which metal ink is discharged as fine droplets. The ink jet method draws a wiring pattern by joining minute droplets, and therefore can quickly respond to changes in internal wiring design (for example, high density of internal wiring or narrowing of wiring width and wiring pitch). be able to.
JP 2005-57139 A

  By the way, the droplet landed on the green sheet varies with time in size, shape, and the like based on the surface state of the green sheet and the surface tension of the droplet. The size of the wiring pattern is regulated according to the drying timing of the droplet whose size or shape varies. For example, a droplet made of metal ink having an outer diameter of 30 μm reaches the lyophilic green sheet and expands the outer diameter to 70 μm after 100 milliseconds, and after 200 milliseconds, the outer diameter decreases. Further, the thickness is set to 100 μm. Therefore, if the drying timing of the droplets varies within a range from 100 milliseconds to 200 milliseconds, the line width of the corresponding wiring pattern varies within a range of about 70 μm to 100 μm.

  Therefore, in order to suppress variation in pattern size, laser drying in which laser light is irradiated to the droplets that have landed on the green sheet has been proposed. In laser drying, droplets are dried only in the laser light irradiation region. For this reason, the drying timing of the landed droplets can be controlled with high accuracy, and variations in pattern size can be suppressed.

  However, in a droplet discharge device used for the ink jet method, in general, the gap between the droplet discharge head and the object is narrowed to several hundred μm in order to ensure the droplet landing accuracy. For this reason, when drying a droplet immediately after landing, that is, a droplet located immediately below the droplet discharge head, it is along a substantially tangential direction of the target in a narrow gap between the droplet discharge head and the target. The laser beam must be irradiated. As a result, the optical cross section (beam spot) of the laser light formed on the object is enlarged, and the intensity of the laser light necessary for drying the droplets cannot be secured. For this reason, there is a risk of insufficient drying of the droplets, resulting in poor pattern formation.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the drying efficiency of droplets and reduce the formation failure of patterns composed of droplets, and droplet ejection. An apparatus and a circuit module are provided.

  In the pattern forming method of the present invention, a discharge port for discharging a pattern forming material into a plurality of droplets on a substrate is scanned relative to the substrate along one direction of the substrate, and along the one direction. In the pattern forming method, in which the bonded droplets are dried to form a pattern along the one direction on the substrate, the one direction substantially toward the bottom outer peripheral portion on the one direction side of the bonded droplets. A laser beam along the reverse direction was irradiated.

  According to the pattern forming method of the present invention, laser light along substantially the opposite direction of one direction is irradiated to the outer peripheral portion of the bottom portion on the one direction side of the droplet bonded along one direction. Therefore, laser light along substantially the opposite direction of one direction is incident along the substantially normal direction of the surface of the droplet from the outer peripheral portion of the bottom of the bonded droplet in one direction. As a result, the laser beam with a reduced amount of reflection on the droplet surface is transmitted across the bonding direction of the bonded droplets. Therefore, it is possible to increase the irradiation amount of the laser light irradiated per discharged droplet and improve the drying efficiency of the droplet. That is, it is possible to reduce the formation failure of the pattern made of droplets.

  Further, in this pattern forming method, the one of the bonded droplets is reflected so that a laser beam transmitted through the bonded droplets is multiply reflected between the substrate and the surface of the bonded droplets. You may make it irradiate the laser beam in alignment with the substantially tangent direction of the said board | substrate toward the bottom part outer peripheral part of a direction side.

  According to this pattern formation method, the laser light that passes through the bonded droplets is subjected to multiple reflections within the bonded droplets. Therefore, it is possible to further improve the utilization efficiency of the laser light applied to the droplets, and to more reliably reduce pattern formation defects.

  The droplet discharge device of the present invention includes a discharge port that discharges a pattern forming material into a plurality of droplets onto a substrate, and the discharge port so that the plurality of droplets join along one direction of the substrate. And a scanning unit that scans relative to the substrate along the one direction, and laser irradiation that irradiates the substrate with laser light along a direction substantially opposite to the one direction. And a control means for driving and controlling the scanning means so that the bottom outer peripheral portion on the one-direction side of the joined droplet is positioned in the laser light region.

  According to the droplet discharge device of the present invention, the laser irradiation unit irradiates the laser beam along the substantially opposite direction of one direction to the outer peripheral portion of the bottom portion on the one direction side of the droplet bonded along the one direction. Therefore, laser light along substantially the opposite direction of one direction is incident along the substantially normal direction of the surface of the droplet from the outer peripheral portion of the bottom of the bonded droplet in one direction. As a result, the laser beam with a reduced amount of reflection on the droplet surface is transmitted across the bonding direction of the bonded droplets. Therefore, it is possible to increase the irradiation amount of the laser light irradiated per discharged droplet and improve the drying efficiency of the droplet. That is, it is possible to reduce the formation failure of the pattern made of droplets.

  Further, in this droplet discharge device, the laser irradiation unit may cause multiple reflections of the laser light incident on the bonded droplet between the substrate and the droplet surface of the bonded droplet. The laser beam may be irradiated toward the substrate along a substantially tangential direction of the substrate.

  According to this droplet discharge device, laser light that passes through the bonded droplets is subjected to multiple reflections within the bonded droplets. Therefore, it is possible to further improve the utilization efficiency of the laser light applied to the droplets, and to more reliably reduce pattern formation defects.

The droplet discharge device further includes a carriage on which the droplet discharge head having the discharge port is mounted. The laser irradiation unit is mounted on the carriage and emits the laser beam; and the carriage And an irradiation optical system that irradiates the substrate with laser light emitted from the semiconductor laser along a direction substantially opposite to the one direction.

  According to this droplet discharge device, the droplet discharge head mounted on the carriage discharges droplets toward the substrate. Further, a semiconductor laser and an irradiation optical system mounted on the carriage irradiate laser light toward the substrate along a direction substantially opposite to one direction. Therefore, the relative position of the laser beam can be maintained with respect to the landing position of the droplet. For this reason, laser light along substantially the opposite direction of one direction can be incident on the outer peripheral portion of the bottom portion on the one direction side of the bonded droplets more reliably. As a result, it is possible to reduce the formation failure of the pattern composed of droplets with higher reproducibility. In addition, the droplet discharge device can be reduced in size and weight.

In this droplet discharge device, the pattern forming material may be a metal ink in which metal fine particles are dispersed, and the substrate may be a low-temperature fired ceramic substrate.
According to this droplet discharge device, laser light is simultaneously applied to a plurality of droplets of metal ink landed on a low-temperature fired ceramic substrate, and the amount of reflection on the droplet surface is reduced. Therefore, it is possible to improve the drying efficiency of the metal ink, and it is possible to reduce defective formation of a pattern made of the metal ink (for example, a wiring pattern or an element pattern of a low-temperature fired ceramic substrate).

  The circuit module of the present invention is a circuit module comprising: a substrate; a circuit element formed on the substrate; and a metal wiring formed on the substrate and electrically connected to the circuit element. Was formed by the droplet discharge device.

  According to the circuit module of the present invention, formation defects of metal wiring can be reduced.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. First, the circuit module 1 of the present invention will be described.
In FIG. 1, a circuit module 1 includes an LTCC multilayer substrate 2 formed in a plate shape, and a plurality of semiconductor chips 3 that are wire-bonded or flip-chip connected above the LTCC multilayer substrate 2. ing.

  On the LTCC multilayer substrate 2, a plurality of low-temperature fired ceramic substrates (hereinafter simply referred to as insulating layers 4) formed in a sheet shape are laminated. Each insulating layer 4 is a sintered body made of a glass ceramic material (for example, a mixture of a glass component such as borosilicate alkali oxide and a ceramic component such as alumina), and has a thickness of several hundred μm. Yes.

  Between each insulating layer 4, various circuit elements 5 such as a resistance element, a capacitive element, and a coil element, and a plurality of internal wirings 6 as metal wirings that electrically connect each circuit element 5 are formed. ing. Each circuit element 5 and each internal wiring 6 are sintered bodies of metal fine particles such as silver and silver alloy, and are formed by using the droplet discharge device 10 of the present invention. Via wirings 7 having a stacked via structure or a thermal via structure are formed in each insulating layer 4, and each circuit element 5 and each internal wiring 6 are electrically connected between the layers. Each via wiring 7 is a sintered body of fine metal powder such as silver or silver alloy, like each circuit element 5 and each internal wiring 6.

Next, a manufacturing method of the LTCC multilayer substrate 2 will be described with reference to FIG.
In FIG. 2, first, via holes 7H are punched and formed on a green sheet 4S as a substrate that enables the insulating layer 4 to be cut out, by punching or laser processing. Next, screen printing using a metal paste is performed a plurality of times on the green sheet 4S, and the via hole 7H is filled with the metal paste to form a via pattern 7F made of the metal paste. Next, the upper surface of the green sheet 4S (hereinafter, simply referred to as the pattern formation surface 4Sa) using the metal ink F (in this embodiment, aqueous silver ink) as a pattern formation material in which metal nanoparticles are dispersed in an aqueous solvent. Inkjet printing is applied.

  More specifically, the droplet Fb of the metal ink F is ejected onto the pattern formation surface 4Sa on the area for forming the circuit element 5 and the internal wiring 6 (hereinafter simply referred to as the pattern formation area). The droplets Fb landed on are dried. Then, the discharging operation and the drying operation are repeated, and the element pattern 5F and the wiring pattern 6F corresponding to the pattern formation region are drawn. At this time, the droplet Fb that has landed on the pattern formation region is dried by making laser light (incident light Le) incident on the landed droplet Fb.

  When the element pattern 5F, the wiring pattern 6F, and the via pattern 7F are formed on the green sheet 4S, a plurality of green sheets 4S are stacked together, and a region corresponding to the LTCC multilayer substrate 2 is cut out as a stacked body 4B and fired. That is, the green sheet 4S, the element pattern 5F, the wiring pattern 6F, and the via pattern 7F are collectively laminated and fired simultaneously. Thus, the LTCC multilayer substrate 2 having the insulating layer 4, the circuit element 5, the internal wiring 6, and the via wiring 7 is formed.

Next, the droplet discharge device 10 for drawing the element pattern 5F and the wiring pattern 6F will be described with reference to FIG. FIG. 3 is an overall perspective view showing the droplet discharge device 10.
In FIG. 3, the droplet discharge device 10 includes a base 11 formed in a rectangular parallelepiped shape. A pair of guide grooves 12 extending along the longitudinal direction (Y arrow direction) is formed on the upper surface of the base 11. Above the guide groove 12, a stage 13 is provided as a scanning unit that moves along the guide groove 12 in the Y arrow direction and the counter-Y arrow direction. A placement portion 14 is formed on the upper surface of the stage 13, and the green sheet 4S with the pattern formation surface 4Sa on the upper side is placed. The placement unit 14 positions and fixes the placed green sheet 4S with respect to the stage 13, and conveys the green sheet 4S in the Y arrow direction and the anti-Y arrow direction. In the present embodiment, in FIG. 3, the Y arrow direction is defined as the scanning direction. Moreover, the conveyance speed along the scanning direction of the green sheet 4S is defined as the scanning speed Vy.

  On the base 11, guide members 16 formed in a gate shape are installed on both sides in the X arrow direction orthogonal to the scanning direction so as to straddle the base 11. On the upper side of the guide member 16, an ink tank 17 extending in the direction of the arrow X is disposed. The ink tank 17 stores the metal ink F, and supplies the metal ink F to a droplet discharge head (hereinafter simply referred to as “discharge head”) 21 disposed below at a predetermined pressure.

  A pair of upper and lower guide rails 18 extending in the X arrow direction are formed on the side opposite to the Y arrow direction of the guide member 16 over substantially the entire width in the X arrow direction. A carriage 20 is attached to the pair of guide rails 18 and moves along the guide rails 18 in the X arrow direction and the counter X arrow direction. An ejection head 21 is mounted on the bottom surface 20a of the carriage 20 on the scanning direction side. 4 is a perspective view of the ejection head 21 as viewed from the lower side (the green sheet 4S side), and FIG. 5 is a cross-sectional view taken along line AA of FIG. FIG. 6 is a schematic side view of the carriage 20.

In FIG. 4, the discharge head 21 is formed in a rectangular parallelepiped shape extending in the X arrow direction. A nozzle plate 22 is provided on the lower side of the discharge head 21 (the green sheet 4S side: the upper side in FIG. 4). The nozzle plate 22 is formed in a plate shape extending in the direction of the arrow X, and a nozzle forming surface 22a is formed on the lower surface (the upper surface in FIG. 4). The nozzle formation surface 22a is formed substantially parallel to the pattern formation surface 4Sa of the green sheet 4S, and when the green sheet 4S is positioned directly below the ejection head 21, the distance between the nozzle formation surface 22a and the pattern formation surface 4Sa. (Platen gap) is kept at a predetermined distance (in this embodiment, 300 μm). On the nozzle forming surface 22a, nozzles N as a plurality of ejection openings formed penetrating in the normal direction of the nozzle forming surface 22a are arranged along the X arrow direction.

  In FIG. 5, cavities 23 communicating with the ink tanks 17 are formed above the nozzles N, respectively. The cavity 23 supplies the metal ink F from the ink tank 17 to the corresponding nozzle N. A vibration plate 24 is attached to the upper side of each cavity 23 to vibrate in the vertical direction and expand and contract the volume in the cavity 23. A plurality of piezoelectric elements PZ corresponding to the nozzles N are disposed on the upper side of the vibration plate 24. Each piezoelectric element PZ contracts and expands in the vertical direction to vibrate the corresponding region of the diaphragm 24 in the vertical direction, and the metal ink F is supplied from the corresponding nozzle N to a predetermined volume (in this embodiment, 10 pl) of liquid. A droplet Fb is discharged. The droplet Fb flies in the direction opposite to the arrow Z of the corresponding nozzle N and lands on a position on the opposing pattern formation surface 4Sa. In the present embodiment, the position on the pattern forming surface 4Sa and corresponding to the anti-Z arrow direction of each nozzle N, that is, the position where the droplet Fb lands is defined as the landing position P.

  While the landing droplet Fb is scanned in the scanning direction, the droplet Fb wets and spreads along the pattern formation surface 4Sa and joins the droplet Fb that has landed in advance. Each of the droplets Fb to be bonded forms a liquid film FL extending along the scanning direction, and forms a liquid surface FLa parallel to the pattern forming surface 4Sa over the entire top surface.

  In the present embodiment, the time required for the landed droplet Fb to form the liquid film FL is defined as the irradiation standby time T. Further, the distance over which the droplet Fb is scanned during the irradiation waiting time T is defined as the irradiation waiting distance WF (= scanning speed Vy × irradiation waiting time T). Further, a position that is displaced from the landing position P by the irradiation standby distance WF in the scanning direction is defined as the reflection position Pe.

  That is, the droplet Fb that lands at the landing position P moves from the landing position P to the reflection position Pe that is displaced by the irradiation waiting distance WF in the scanning direction when the irradiation waiting time T elapses from the landing, and the preceding droplet Fb. And a liquid film FL extending in the scanning direction is formed. In this embodiment, the shape of the landed droplet Fb is observed using a landing observation camera such as an ultra-high speed camera, and the irradiation waiting time T is defined based on the change in the shape of the droplet over time.

  In FIG. 6, an emission hole H penetrating to the inside of the carriage 20 is formed on the bottom surface 20 a of the carriage 20 in the anti-scanning direction (anti-Y arrow direction) of the ejection head 21. The exit hole H is formed so that the width in the X arrow direction is substantially the same as the width of the ejection head 21 in the X arrow direction. On the upper side of the emission hole H, a semiconductor laser LD constituting laser irradiation means is disposed.

  The semiconductor laser LD emits downward a band-shaped collimated linearly polarized laser beam extending substantially in the X-arrow direction of the emission hole H in the downward direction. The wavelength of the laser beam emitted from the semiconductor laser LD is set to a wavelength range within the absorption wavelength range of the metal ink F and reflected by the green sheet 4S (pattern forming surface 4Sa) (in this embodiment, 808 nm). ing.

Inside the exit hole H, a cylindrical lens 25 constituting an irradiation optical system is disposed. The cylindrical lens 25 is a lens having a curvature only in the Y arrow direction, and the width in the X arrow direction is the same size as the width of the ejection head 21 in the X arrow direction. When receiving the laser beam from the semiconductor laser LD, the cylindrical lens 25 converges only the component in the Y arrow direction (or anti-Y arrow direction) of the laser beam and emits it downward as incident light Le.

  Below the exit hole H, a mirror stage 26 extending below the carriage 20 and a reflection mirror 27 that is rotatably supported by the mirror stage 26 and constitutes an irradiation optical system are disposed. The mirror stage 26 supports the reflection mirror 27 so as to be rotatable about a rotation axis along the X arrow direction. The reflection mirror 27 is a plane mirror having a reflection surface 27m on the cylindrical lens 25 side, and the width in the X arrow direction is the same size as the width of the ejection head 21 in the X arrow direction.

  The reflection mirror 27 receives the incident light Le from the cylindrical lens 25 by the reflection surface 27m, reflects the incident light Le along the substantially tangential direction (substantially scanning direction) of the pattern formation surface 4Sa, and forms the incident light Le and the pattern formation. An angle (irradiation angle θe) formed by the normal line of the surface 4Sa is set to approximately 90 ° (88 ° in this embodiment). The reflection mirror 27 guides the beam waist of the incident light Le traveling substantially in the scanning direction to the reflection position Pe located below the ejection head 21. Incident light Le guided to the reflection position Pe is incident inward from the outer periphery of the bottom of the liquid film FL on the side opposite to the scanning direction when the droplet Fb moves to the reflection position Pe to form the liquid film FL. To do.

  At this time, the angle formed between the normal direction of the bottom surface of the liquid film FL and the tangential direction of the pattern formation surface 4Sa is smaller than that of the other film surface (for example, the liquid surface FLa). . Therefore, the incident light Le incident on the bottom outer periphery of the liquid film FL has a smaller angle (“incident angle”) between the incident direction and the normal direction of the film surface than other film surfaces.

  On the other hand, the incident light Le incident on the outer periphery of the bottom part reflects as the reflected light the part not transmitted through the liquid film FL. The reflectance of the incident light Le is derived by the following equations when the polarization state is P-polarized light (reflectance Rp) and when it is S-polarized light (reflectance Rs). However, the refractive index of air is N1, the refractive index of the liquid film FL is N2, and the “incident angle” is θ.

  Both the reflectance Rp and the reflectance Rs decrease as the “incident angle” decreases. Therefore, incident light Le incident on the outer periphery of the bottom of the liquid film FL reduces the amount of reflection on the film surface and transmits the liquid film FL by an amount that reduces the “incident angle”.

  However,

  A part of the incident light Le that passes through the liquid film FL is absorbed by the metal ink F and starts to dry the corresponding liquid film FL. On the other hand, the portion that is not absorbed by the metal ink F is reflected on the pattern forming surface 4Sa. Incident at position Pe. The incident light Le incident on the reflection position Pe is reflected by the pattern formation surface 4Sa, and becomes reflected light Lr that travels from the reflection position Pe toward the liquid surface FLa along the substantially scanning direction.

  A part of the reflected light Lr is absorbed by the metal ink F and promotes drying of the corresponding region of the liquid film FL, while the portion not reflected by the metal ink F enters the liquid surface FLa. The reflected light Lr incident on the liquid level FLa is reflected on the liquid level FLa because the incident angle is larger than the critical angle. The reflected light Lr reflected by the liquid surface FLa again proceeds to the pattern forming surface 4Sa side along the scanning direction.

  That is, the incident light Le that passes through the liquid film FL is reflected multiple times between the pattern formation surface 4Sa and the liquid surface FLa, and is equivalent to a plurality of droplets Fb along the direction in which the droplets Fb are joined (scanning direction). Absorbed in the area. Therefore, the incident light Le transmitted through the liquid film FL increases the irradiation amount of the laser light irradiated per droplet Fb. As a result, the incident light Le reliably dries the droplets Fb to form a layer pattern FP that does not have insufficient drying. Then, by stacking the layer patterns FP in order, the element pattern 5F and the wiring pattern 6F can be formed, and the formation defects can be reduced.

Next, the electrical configuration of the droplet discharge device 10 configured as described above will be described with reference to FIG.
In FIG. 7, a control device 40 as a control means includes a CPU, a ROM, a RAM, and the like, and moves the stage 13 and the carriage 20 in accordance with the stored various data and various control programs, as well as the semiconductor laser LD and the piezoelectric devices. The drive of the element PZ is controlled.

  An input device 41 having operation switches such as a start switch and a stop switch is connected to the control device 40. The input device 41 inputs information related to the position coordinates of the pattern formation region (layer pattern FP) with respect to the drawing plane (pattern formation surface 4Sa) to the control device 40 as drawing information Ia in a predetermined format. The control device 40 receives the drawing information Ia from the input device 41 and generates bitmap data BMD.

  The bitmap data BMD is data that specifies whether each piezoelectric element PZ is turned on or off according to the value (0 or 1) of each bit. The bitmap data BMD is data that defines whether or not the droplets Fb are ejected to respective positions on the drawing plane (pattern formation surface 4Sa) through which the ejection head 21 passes. That is, the bitmap data BMD is for discharging the droplet Fb to each target position defined in the pattern formation region.

  An X-axis motor drive circuit 42 is connected to the control device 40 and outputs a drive control signal corresponding to the X-axis motor drive circuit 42. In response to the drive control signal from the control device 40, the X-axis motor drive circuit 42 rotates the X-axis motor MX for moving the carriage 20 forward or backward. An X-axis encoder XE is connected to the X-axis motor drive circuit 42, and a detection signal from the X-axis encoder XE is input. Based on the detection signal from the X-axis encoder XE, the X-axis motor drive circuit 42 generates a signal related to the moving direction and moving amount of the carriage 20 (each landing position P) with respect to the pattern forming surface 4Sa and outputs the signal to the control device 40. To do.

  A Y-axis motor drive circuit 43 is connected to the control device 40 and outputs a drive control signal corresponding to the Y-axis motor drive circuit 43. In response to the drive control signal from the control device 40, the Y-axis motor drive circuit 43 rotates the Y-axis motor MY for moving the stage 13 forward or backward. That is, the control device 40 scans the stage 13 (pattern forming surface 4Sa) by the irradiation standby distance WF during the irradiation standby time T via the Y-axis motor drive circuit 43, and the droplet Fb positioned at the reflection position Pe. A liquid film FL is formed.

  A Y-axis encoder YE is connected to the Y-axis motor drive circuit 43, and a detection signal is input from the Y-axis encoder YE. The Y-axis motor drive circuit 43 generates a signal related to the moving direction and moving amount of the stage 13 (pattern forming surface 4Sa) based on the detection signal from the Y-axis encoder YE, and outputs the signal to the control device 40. The control device 40 calculates the relative position of the landing position P with respect to the pattern forming surface 4Sa based on the signal from the Y-axis motor drive circuit 43, and every time the target position is located at the corresponding landing position P, the discharge timing signal LP. Is output.

  The control device 40 is connected to the semiconductor laser drive circuit 44, and outputs a drawing start signal S1 when starting a drawing operation, and outputs a drawing end signal S2 when ending the drawing operation. The semiconductor laser drive circuit 44 inputs the drawing start signal S1 from the control device 40 to emit laser light to the semiconductor laser LD, and inputs the drawing end signal S2 from the control device 40 to transmit the laser light to the semiconductor laser LD. Stop emission. That is, the control device 40 drives and controls the semiconductor laser LD during the drawing operation via the semiconductor laser drive circuit 44, and performs the laser light irradiation operation.

  A discharge head drive circuit 45 is connected to the control device 40, and a piezoelectric element drive voltage COM1 for driving each piezoelectric element PZ is output in synchronization with the discharge timing signal LP. Further, the control device 40 generates an ejection control signal SI synchronized with a predetermined clock signal based on the bitmap data BMD, and serially transfers the ejection control signal SI to the ejection head drive circuit 45. The ejection head drive circuit 45 sequentially converts the ejection control signal SI from the control device 40 into serial / parallel corresponding to each piezoelectric element PZ. Each time the ejection head drive circuit 45 receives the ejection timing signal LP from the control device 40, the ejection head drive circuit 45 latches the serial / parallel converted ejection control signal SI and supplies the piezoelectric element drive voltage COM1 to each selected piezoelectric element PZ. To do.

Next, a method for drawing the element pattern 5F and the wiring pattern 6F using the droplet discharge device 10 will be described.
First, as shown in FIG. 3, the green sheet 4S is placed on the stage 13 so that the pattern formation surface 4Sa is on the upper side. At this time, the stage 13 arranges the green sheet 4S in the anti-scanning direction of the carriage 20.

  From this state, the drawing information Ia is input from the input device 41 to the control device 40, and the control device 40 generates and stores bitmap data BMD based on the drawing information Ia. Next, when the green sheet 4S is scanned, the control device 40 causes the carriage 20 (ejection head 31) to a predetermined position via the X-axis motor drive circuit 42 so that the target position passes the corresponding landing position P. Move to place. When the carriage 20 is arranged and moved, the control device 40 starts scanning the green sheet 4S via the Y-axis motor drive circuit 43.

  When scanning of the green sheet 4S is started, the control device 40 outputs a drawing start signal S1 to the semiconductor laser drive circuit 44 and emits laser light from the semiconductor laser LD. Laser light emitted from the semiconductor laser LD is guided to the reflection position Pe of the pattern forming surface 4Sa as incident light Le substantially along the scanning direction via the reflection mirror 27.

When the scanning of the green sheet 4S is started, the control device 40 outputs an ejection control signal SI generated based on the bitmap data BMD to the ejection head drive circuit 45.
When the scanning of the green sheet 4S is started, the control device 40 outputs the ejection timing signal LP to the ejection head drive circuit 45 every time the target position is located at the corresponding landing position P. That is, every time the control device 40 selects the nozzle N for discharging the droplet Fb based on the discharge control signal SI and the landing position P corresponding to the selected nozzle N is located at the target position, the target position A droplet Fb is discharged toward the surface.

  Each discharged droplet Fb lands on a corresponding target position on the pattern formation surface 4Sa. When the droplets Fb that have landed at each target position are scanned by the irradiation standby distance WF in the scanning direction, the droplets Fb join with the preceding droplets Fb in the vicinity of the reflection position Pe to form a liquid film FL extending in the scanning direction. . The liquid film FL extending in the scanning direction makes incident light Le substantially along the scanning direction incident on the bottom outer peripheral portion on the side opposite to the scanning direction.

  Incident light Le incident on the outer periphery of the bottom of the liquid film FL is transmitted through the liquid film FL while reducing the amount of reflection on the film surface by an amount that reduces the “incident angle”. Incident light Le that passes through the liquid film FL is multiple-reflected between the pattern formation surface 4Sa and the liquid surface FLa, and is absorbed in a region corresponding to a plurality of droplets Fb joined along the scanning direction.

  Thus, the incident light Le incident on the bottom outer periphery of the liquid film FL improves the drying efficiency of the droplets Fb and forms a layer pattern FP that does not have insufficient drying. Then, by laminating the layer pattern FP in order, the element pattern 5F and the wiring pattern 6F can be formed, and the formation defects are reduced.

Next, effects of the present embodiment configured as described above will be described below.
(1) According to the above embodiment, the reflection mirror 27 mounted on the carriage 20 guides the laser light emitted from the semiconductor laser LD to the reflection position Pe as incident light Le substantially along the scanning direction. Further, the control device 40 scans the droplet Fb landed on the pattern forming surface 4Sa in the scanning direction, and joins the droplet Fb with the preceding droplet Fb when the droplet Fb is located at the reflection position Pe. Then, the incident light Le substantially along the scanning direction is incident on the bottom outer peripheral portion of the liquid film FL composed of the joined droplets Fb on the side opposite to the scanning direction.

  Therefore, the incident light Le incident on the liquid film FL reduces the amount of reflection on the film surface and passes through the liquid film FL substantially along the scanning direction. As a result, the laser beam can be absorbed in the region corresponding to the plurality of droplets Fb along the scanning direction. Therefore, the drying efficiency of the droplets Fb can be improved, and the formation defects of the element pattern 5F and the wiring pattern 6F can be reduced.

  (2) According to the above embodiment, the incident light Le that passes through the liquid film FL undergoes multiple reflections between the pattern formation surface 4Sa and the liquid surface FLa. Therefore, the utilization efficiency of the incident light Le incident on the liquid film FL can be improved, and the drying efficiency of the droplets Fb can be further improved.

  (3) According to the above embodiment, the carriage 20 mounts the ejection head 21, the semiconductor laser LD, the cylindrical lens 25, and the reflection mirror 27. Therefore, the relative position of the incident light Le can be maintained with respect to the landing position P of the droplet Fb. As a result, the incident light Le can be incident on the bottom outer periphery of the liquid film FL on the side opposite to the scanning direction with higher reproducibility. As a result, the dry state of the element pattern 5F and the wiring pattern 6F can be stabilized, and the formation defects of the circuit element 5 and the internal wiring 6 can be further reduced.

In addition, you may change the said embodiment as follows.
In the above embodiment, each liquid film FL is dried by the common incident light Le. For example, the incident light Le from the semiconductor laser LD may be divided corresponding to each nozzle N, and each divided incident light Le may be irradiated only to the corresponding liquid film FL.

  Alternatively, a configuration may be adopted in which semiconductor lasers LD are arranged in the number corresponding to the number of nozzles N, and incident light Le from each semiconductor laser LD is irradiated to the corresponding liquid film FL. At this time, the control device 40, the semiconductor laser drive circuit 44, and the ejection head drive circuit 45 are preferably configured as follows.

  That is, as shown in FIG. 8, the control device 40 outputs the semiconductor laser drive voltage COM2 for driving each semiconductor laser LD to the semiconductor laser drive circuit 44 in synchronization with the ejection timing signal LP. The ejection head drive circuit 45 outputs the ejection control signal SI latched in the delay circuit 44 a provided in the semiconductor laser drive circuit 44. The semiconductor laser driving circuit 44 receives the ejection control signal SI from the ejection head driving circuit 45 by the delay circuit 44a, and waits until the droplet Fb ejected based on the ejection control signal SI reaches the reflection position Pe. Then, at the timing when the droplet Fb reaches the reflection position Pe, the semiconductor laser drive voltage COM2 is supplied to each semiconductor laser LD selected based on the ejection control signal SI. According to this, since the incident light Le is irradiated only to the corresponding liquid film FL, the utilization efficiency of the incident light Le can be improved.

  In the above embodiment, the liquid film FL is dried by the incident light Le. Not limited to this, the liquid film FL may be dried and baked by the incident light Le. According to this, the firing failure of the element pattern 5F and the wiring pattern 6F can be reduced by the incident light Le irradiated locally.

  In the above embodiment, the bitmap data BMD is generated based on the drawing information Ia. However, the present invention is not limited to this, and the bitmap data BMD previously generated by the external device may be input from the input device 41 to the control device 40.

  In the above embodiment, the configuration is such that the incident light Le from the semiconductor laser LD is irradiated to the region of the droplet Fb through the plane mirror. However, the present invention is not limited to this, and the configuration may be such that the incident light Le from the semiconductor laser LD is irradiated onto the region of the liquid film FL via the prism mirror, or the incident light Le from the cylindrical lens 25 is directly applied to the liquid film FL. The structure which is irradiated may be sufficient.

  In the above embodiment, the droplet discharge head is embodied as the piezoelectric element drive type droplet discharge head 21. However, the present invention is not limited to this, and the droplet discharge head may be embodied as a resistance heating type or electrostatic drive type discharge head.

  In the above embodiment, the circuit element 5 and the internal wiring 6 are formed by the ink jet method. However, the present invention is not limited to this, and only a relatively fine circuit element 5 or internal wiring 6 may be formed by the ink jet method described above.

  In the above embodiment, the pattern forming material is embodied in metal ink. For example, the pattern forming material may be embodied as a liquid material in which an insulating film material or an organic material is dispersed. That is, the pattern forming material may be any material that is dried by receiving laser light and forms a solid phase pattern.

  In the above embodiment, the pattern is embodied as the element pattern 5F and the wiring pattern 6F. However, the present invention is not limited to this, and the pattern may be embodied in various metal wirings provided in a liquid crystal display device, an organic electroluminescence display device, a field effect display device (FED, SED, etc.) provided with a planar electron-emitting device. Good. Alternatively, the pattern may be embodied as an identification code composed of a plurality of line patterns or dot patterns. That is, the pattern may be a pattern formed by dried droplets.

The perspective view which shows the circuit module of this invention. Similarly, explanatory drawing explaining the manufacturing method of a circuit module. Similarly, a perspective view showing a droplet discharge device. Similarly, a perspective view showing a droplet discharge head. Similarly, an explanatory view explaining a droplet discharge head. Similarly, an explanatory view for explaining a semiconductor laser. Similarly, the electric block circuit diagram explaining the electrical constitution of a droplet discharge device. The electric block circuit diagram explaining the electric constitution of the droplet discharge apparatus of the example of a change.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit module, 4S ... Green sheet as a board | substrate, 5 ... Circuit element, 5F ... Element pattern which comprises pattern, 6 ... Internal wiring as metal wiring, 6F ... Wiring pattern which comprises pattern, 10 ... Droplet discharge Device: 13 ... Stage as scanning means, 20 ... Carriage, 21 ... Droplet ejection head, 40 ... Control device as control means, F ... Metal ink as pattern forming material, Fb ... Droplet, Le ... Laser light Incident light constituting, Lr... Reflected light constituting laser light, LD... Semiconductor laser constituting laser irradiating means, N.

Claims (7)

A discharge port for discharging the pattern forming material to the substrate as a plurality of droplets is scanned relative to the substrate along one direction of the substrate, and the droplets bonded along the one direction are dried. In the pattern forming method in which the pattern along the one direction is formed on the substrate,
A pattern forming method characterized by irradiating a laser beam along a substantially opposite direction of the one direction toward a bottom outer peripheral portion on the one direction side of the bonded droplet. In the pattern formation method of Claim 1,
The laser beam that passes through the bonded droplets is directed toward the outer periphery of the bottom of the bonded droplets in one direction so that multiple reflections occur between the substrate and the surface of the bonded droplets. And irradiating a laser beam along a substantially tangential direction of the substrate. A discharge port for discharging the pattern forming material into a plurality of droplets on the substrate;
And a scanning unit that scans the ejection port relative to the substrate along the one direction so that the plurality of droplets are joined along the one direction of the substrate. In
Laser irradiation means for irradiating the substrate with laser light along substantially the opposite direction of the one direction;
Control means for driving and controlling the scanning means so that a bottom outer peripheral portion on the one-direction side of the joined droplet is located in the region of the laser beam;
A droplet discharge apparatus comprising: In the droplet discharge device according to claim 3,
The laser irradiation means follows a substantially tangential direction of the substrate so that laser light incident on the bonded droplets is multiply reflected between the substrate and the droplet surface of the bonded droplets. A droplet discharge apparatus irradiating a laser beam toward the substrate. In the droplet discharge device according to claim 3 or 4,
A carriage on which a droplet discharge head having the discharge port is mounted;
The laser irradiation means includes
A semiconductor laser mounted on the carriage and emitting the laser beam;
An irradiation optical system that irradiates laser light emitted from the semiconductor laser mounted on the carriage toward the substrate along a direction substantially opposite to the one direction;
A droplet discharge apparatus comprising: In the liquid droplet ejection device according to any one of claims 3 to 5,
The pattern forming material is a metal ink in which metal fine particles are dispersed,
The droplet discharge device, wherein the substrate is a low-temperature fired ceramic substrate. In a circuit module comprising a substrate, a circuit element formed on the substrate, and a metal wiring formed on the substrate and electrically connected to the circuit element,
The circuit module, wherein the metal wiring is formed by the droplet discharge device according to any one of claims 3 to 6.

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