JP4366377B2 - Circuit pattern forming method and circuit pattern forming apparatus - Google Patents

Description

  The present invention relates to a circuit pattern forming method and a circuit pattern forming apparatus for forming a circuit pattern of a circuit board used for an electronic device, an electric device, a computer, a communication device and the like. In particular, the present invention relates to a circuit pattern forming method and a circuit pattern forming apparatus for forming a circuit by discharging a circuit pattern forming solution onto a substrate.

  A circuit board provided in an electronic device, a communication device, a computer, or the like is mounted with a semiconductor such as an LSI or various electronic components. There are many types of circuit boards, including those based on ceramic, those using a composite material of a reinforcing material such as glass fiber and a synthetic resin such as epoxy resin, polyester resin, aramid resin, etc. Some have a flexible film as a base material. In addition, circuit boards used to be mostly single-sided boards or double-sided boards. However, as circuit boards are becoming smaller and higher in density, boards with circuit patterns are being used, and now there are 8 layers. Multi-layer circuit boards with 16 or 16 layers are the mainstream. Also, circuit patterns have been rapidly miniaturized and densified with the increase in the speed of electronic circuits.

  Patent Document 1 discloses a method of forming a circuit by drawing a conductive pattern and an insulating pattern by ejecting a conductive solution and an insulating solution directly onto the surface of a substrate by an ink jet method. According to this method, there is an advantage that the subtractive method is not required, the number of processes is reduced, and there is no waste liquid treatment generated in the plating process or the etching process.

  In Patent Document 1, a circuit pattern is formed so that adjacent droplets of ink droplets discharged by an ink jet printer overlap each other. This is because if the adjacent droplets do not overlap, the portion where the droplets are not in contact with each other causes disconnection. However, in this method, the liquid droplets discharged onto the base material come into contact with the liquid droplets already on the base material, so that the liquid droplets that come into contact with each other may form a liquid pool.

Here, the liquid pool will be described.
FIG. 18 shows a state in which liquid pools 201 and 203 are generated in the wiring pattern 200. The liquid reservoirs 201 and 203 are liquid droplets that have already been ejected onto the base material when the liquid droplets ejected onto the base material come into contact with the liquid droplets already on the base material. It is caused by being drawn to. If this liquid pool further expands, as shown at 203, the 203 itself may come into contact with other patterns and cause a short circuit. Also, if the ejected droplets land on a position where they do not contact the droplets already ejected on the substrate due to ejection errors of the ejection head, the droplets Fixing is performed in a state separated from the pattern. In this case, disconnection occurs as indicated by a portion 202 in FIG.

  In view of this, a proposal has been made to prevent the above-described liquid pool and prevent problems such as disconnection and short circuit as disclosed in Patent Document 2. In this method, as shown in FIGS. 19A and 19B, first, as a first discharge step, droplets 1003 are discharged from the head 1002 to form dots 1006 on the substrate 1001. The dots 1006 are formed at a pitch 1005 that is larger than the diameter 1004 of the droplets after landing on the substrate 1001. The pitch here means the distance between the centers of adjacent dots.

  Thereafter, a drying process is performed to fix the dots 1006 formed in the first ejection process, and then dots 1007 are formed as a second ejection process. In the formation of the dots 1007, droplets 1003 are discharged at the same pitch 1005 as in the first discharge step at a position different from the discharge position in the first discharge step. Then, a drying process is performed again to fix the dots 1007 formed in the second ejection process, and then dots 1008 are formed as a third ejection process. When forming the dots 1008, the droplets 1003 are ejected at a pitch smaller than the pitch 1005 in the first ejection process.

  As described above, in Patent Document 2, dots are formed on a substrate at intervals, and after fixing the dots in a drying process, droplets are ejected between the dots. For this reason, the landed droplets are not attracted toward the dots already existing on the base material, and the liquid pool can be prevented. Furthermore, in Patent Document 2, as shown in FIG. 19 (b), problems such as disconnection and short circuit do not occur by increasing the thickness of the formed circuit.

Japanese Patent Application Laid-Open No. 07-245467 Japanese Patent Laid-Open No. 2003-136991

  However, since the technique described in Patent Document 2 performs a drying process after each discharge process and increases the thickness of the film, the circuit pattern after the third discharge process has a non-uniform thickness. Therefore, there is a problem that the flatness of the surface is impaired. For this reason, it is unsuitable for forming a circuit pattern having a uniform thickness and flatness with a thin film essential for forming a multilayer circuit board. On the other hand, in recent years, circuit boards have become denser, and there is an increasing demand for circuit patterns capable of forming a thin film with a multi-layer structure. However, the technique of Patent Document 2 cannot sufficiently meet this requirement. It has become.

  The present invention has been made paying attention to the above-mentioned problems of the prior art, and when forming a circuit pattern on a substrate, problems such as disconnection and short circuit do not occur, and a circuit pattern having a uniform thickness is formed with a thin film. An object of the present invention is to provide a circuit pattern forming apparatus and a circuit pattern forming method that can be formed.

In order to achieve the above object, the present invention has the following configuration.
In other words, the first aspect of the present invention is a circuit pattern forming method for forming a circuit pattern by discharging a liquid for forming a circuit pattern onto a substrate using a liquid discharge means, which is greatly increased from the first nozzle. A first ejection step of ejecting liquid droplets to form a plurality of liquid first dots on the substrate with a gap, and a second nozzle before the liquid first dots solidify A small liquid droplet smaller than the large liquid droplet is discharged , and a liquid second dot is further formed between the liquid first dots on the substrate, and the liquid first dot and the liquid liquid are formed. A second ejection step of forming a liquid circuit pattern flattened by mixing with the second dots; and a fixing step of solidifying the liquid circuit pattern by heating. To do.

According to a second aspect of the present invention, a circuit pattern is formed by forming a circuit pattern by forming a plurality of liquid dots on the substrate by discharging a liquid for forming a circuit pattern onto the substrate by a liquid discharge unit. An apparatus for moving the liquid ejection unit relative to the substrate; a detection unit for detecting a relative position between the liquid ejection unit and the substrate; and a liquid ejection detected by the detection unit. Based on the relative position between the means and the substrate and the data forming the circuit pattern, a large liquid drop was ejected from the first nozzle to form a liquid first dot on the substrate. later, the liquid between the first dot of the liquid formed in said said substrate by ejecting large liquid droplets smaller than the small droplet from the second nozzle before the first dot of the liquid is solidified Shape 2 dots further And control means for forming a liquid circuit pattern that is flattened by mixing the liquid first dots and the liquid second dots .

  In the present invention, after the droplets are ejected so that a gap is formed between the dots formed on the substrate, before the dots formed on the substrate solidify, the dots to be connected A droplet is discharged in the gap. Thereby, a flat thin film having a substantially uniform thickness can be easily formed on the substrate. For this reason, the present invention can reduce the occurrence of problems such as disconnection and short circuit and erroneous conduction, and can also cope with higher density and multilayering required for circuit boards in recent years.

Hereinafter, embodiments of the present invention will be described in the following order.
1. 1. Configuration of circuit pattern forming apparatus 2. Configuration of control system 3. Control of circuit formation position Materials used for circuit pattern formation 4-1. Substrate 4-2. 4. Conductive solution and insulating solution Circuit pattern forming method

[1. Configuration of circuit pattern forming apparatus]
First, as an embodiment of the present invention, a circuit pattern forming apparatus used for forming a circuit pattern composed of an insulating pattern and a conductive pattern on a substrate will be described.

  A circuit pattern forming apparatus used in the present embodiment shown in FIG. 1 includes a carriage 109 that reciprocates along the main scanning direction (X direction), a stage 103 on which a substrate 1 for forming a circuit pattern is mounted, and the like. Have. In this carriage, a liquid discharge head 2 for discharging an insulating solution onto a substrate 1, a liquid discharge head 3 for injecting a conductive solution, and an insulating solution and a conductive material for both liquid discharge heads 2 and 3 are provided. Two tanks (not shown) for supplying each solution are mounted.

  FIG. 2 is a diagram schematically illustrating nozzle rows arranged on the orifice surface of the liquid discharge head 2. As shown in FIG. 2, the liquid ejection head 2 is provided with a large nozzle 20 that ejects relatively large droplets and a large nozzle row 30a in which the large nozzles 20 are arranged at equal intervals. Although not shown in FIG. 2, the liquid ejection head 3 is also provided with a large nozzle 20 and a large nozzle row 30 a similar to the liquid ejection head 2.

  In FIG. 1, a CR linear motor (carriage linear motor) 101 is used as a power source for moving the carriage 109 in the forward direction (hereinafter referred to as forward scanning) and in the backward direction (hereinafter referred to as backward scanning). Provided. Furthermore, a stage 103 and an LF linear motor (line feed linear motor) 102 are provided as a substrate moving means for moving the substrate 1 in the Y direction. The LF linear motor 102 is firmly fixed to the surface plate 108 so that the upper surface of the stage 103 on which the substrate 1 is placed can always be kept parallel to the upper surface of the surface plate 108 even if the stage 103 moves. ing. On the other hand, the CR linear motor 101 is fixed on the surface plate 108 through the bases 104 and 105 so as to maintain high rigidity.

Further, the carriage 109 reciprocates along the main scanning direction (X direction) with respect to the upper surface of the surface plate surface, that is, the stage surface. The CR linear motor 101 and the LF linear motor 102 incorporate linear encoders 111 and 112 and origin sensors 106 and 107, respectively, and their outputs are used as servo control inputs when each linear motor is driven. Furthermore, the linear encoder 111 on the carriage side is also used for generating the discharge timing of the solution.
In addition, a personal computer (not shown) is connected as a host device to the circuit pattern forming apparatus in the present embodiment. Based on the graphic information (circuit pattern information) sent from the personal computer, the circuit pattern forming apparatus moves the liquid discharge heads 2 and 3, discharges each solution, moves the stage 103, etc. A circuit pattern is formed on the surface.

  A heater (not shown) is embedded under the stage 103 that supports the substrate 1, and the circuit pattern drawn on the substrate is heated by the heater so that a circuit is formed. The pattern is fixed. In the case of this embodiment, since the purpose is to fix the circuit pattern, the set temperature of the heater is set to 40 to 70 ° C. Thus, the solution on the substrate 1 can be sufficiently fixed even with a simple configuration in which the heater is embedded in the stage 103. If fixing is completed, there will be no functional problem as a circuit board. However, if you want to further improve the conductivity of the conductor pattern and the insulation of the insulation pattern, use a separately prepared bake device. It is good to fire.

[2. Configuration of control system]
Next, a control system of the circuit pattern forming apparatus of this embodiment will be described.
FIG. 3 is a block diagram schematically showing the overall configuration of the control system in the circuit pattern forming apparatus of the present embodiment. The mechanism unit 46 includes a CR linear motor 101 for moving the carriage 109 on which the liquid discharge head 2 is mounted in the main scanning direction, an LF linear motor 102 for transporting the stage 103 on which the substrate 1 is mounted, and the like.

  The main control unit 44 is a central part that controls the entire circuit pattern forming apparatus according to the present embodiment including the liquid discharge head and the mechanism unit 46. The main control unit 44 includes a ROM that stores a CPU, an operation program, and the like, and a working RAM that enables writing and reading of various data.

  The main control unit 44 outputs a control signal to the mechanism unit 46 to perform mechanism control such as movement of the carriage 109 and movement of the stage 103. Further, the main control unit 44 also exchanges signals with the head control unit 42, the memory control unit 50, the drawing position signal generation unit 41, and the like, and controls the driving of the liquid ejection head 2. The I / F unit 47 receives commands and circuit pattern drawing data (circuit pattern formation data) from a personal computer at an interface portion between a personal computer (not shown) and a circuit pattern forming apparatus. The memory control unit 50 transfers the command input from the I / F unit 47 to the main control unit 44 and, at the same time, controls the main control unit 44 to write the drawing data into the buffer memory 45 and the address signal and the write timing signal. Is generated.

Further, the main control unit 44 analyzes the command input from the I / F unit 47, sets drawing conditions such as drawing speed and drawing resolution based on the analysis result, and based on the drawing conditions, the mechanism unit 46 and the drawing position. The signal generator 41 is controlled to perform drawing under a predetermined condition.
The drawing data received from a personal computer (not shown) is stored in the buffer memory 45, which is a temporary memory, and then transferred to the head control unit 42 under the control of the memory control unit 50 that receives a command from the main control unit 44. The

  The head control unit 42 performs drawing by driving each nozzle of the liquid ejection head in accordance with the drawing data transferred from the buffer memory 45 in synchronization with the drawing position signal output from the drawing position signal generating unit 41.

[3. Control of drawing position]
Next, a method for controlling the drawing position in the circuit pattern forming apparatus of this embodiment will be described.
4A and 4B are diagrams showing output signals of the linear encoder 111. FIG. In the figure, two signals A and B whose phases are shifted by 90 ° are signals generated by the linear encoder 111. 4A shows signals A and B generated when the carriage 109 operates in the forward direction, and FIG. 4B shows signals A and B generated when the carriage 109 operates in the backward direction. ing. As shown in FIG. 4A, when the phase of the signal A is advanced by 90 ° from the phase of the signal B, the carriage 109 is moving in the forward direction. For this reason, in this state, the count-up is performed according to the rising and falling edges of each signal. Further, as shown in FIG. 4B, when the phase is delayed by 90 °, the carriage 109 is moved in the backward direction, so that it counts down.

  In this way, the movement position of the carriage 109 can be detected by counting the output signal of the linear encoder 111. 3 receives the two signals A and B from the linear encoder 111 and the origin signal Z output from the origin sensor 106, and receives the absolute position of the carriage 109 in the current main scanning direction. That is, the position from the origin is detected.

FIG. 5 is a diagram illustrating an example of a circuit of the liquid ejection head position detection unit 40. The detection unit 40 is configured to count signals (PLS) and up / down signals based on the signals A and B from the linear encoder 111, the origin signal Z from the origin sensor 106, and a clock (CLK) for synchronizing logic. That is, a moving direction signal (DIR) is generated. The circuit composed of 201 to 204 in FIG. 5 is a part that detects the rising and falling timings of A. A pulse synchronized with the rising timing of A is output from the circuit 203, and a pulse synchronized with the falling timing is output from the circuit 204.
Similarly, the circuit composed of 205 to 208 in FIG. 5 is a part for detecting the rising and falling timings of B. A pulse synchronized with the rising timing of B is output from the circuit 205, and a pulse synchronized with the falling timing is output from the circuit 208.

FIG. 6 is a timing chart showing output signals of respective parts in the circuit shown in FIG.
In FIG. 6, since the phase of A at the beginning is 90 ° ahead of the phase of B, the moving direction signal DIR is a low level signal indicating the forward direction. Furthermore, since the phase is delayed by 90 ° from the middle of FIG. 6, it can be seen that the moving direction signal DIR is a high level signal indicating the backward direction. The count signal PLS outputs a pulse at the rising and falling timings of the two signals A and B.

  The origin signal Z, the count signal PLS, and the movement direction signal DIR are connected to input terminals of the reset (CLR), clock (CK), and up / down (UP / DW) of the up / down counter 210 shown in FIG. . Accordingly, when the carriage 109 is moved to the origin position by the initialization command of the main control unit 44, the origin signal Z becomes active and the count value is cleared (count value = 0). Thereafter, the count value = 0 is set as the origin, and the absolute position of the carriage 109 in the main scanning direction is output to the drawing position signal generation unit 41 as the count value.

  FIG. 7 is a block diagram of the drawing position signal generator 41. The count value generated by the liquid discharge head position detection unit 40 in FIG. 5 is connected to the address input terminal of the RAM 300 via the selector 301. In the RAM 300, the address bus is connected to the address input terminal (AB terminal) of the RAM 300 via the other input of the selector 301 so that the CPU in the main control unit 44 can directly read / write (R / W). It is connected to the. Further, the CPU data bus in the main control unit 44 is connected to the data bus terminal (DB terminal) of the RAM 300, and the CPU access signal is also input to the R / W terminal of the RAM 300.

  When data is written from the main control unit 44 to the RAM 300, the selector 301 is connected to the CPU side. Further, during the drawing operation, the selector 301 is switched so that the count value becomes the address input of the RAM 300, and RAM data at an address corresponding to the position of the carriage 109 is output to the head controller 42 as the carriage 109 moves.

  Here, if drawing data is written in advance in the RAM 300 from the CPU of the main control unit 44, a drawing position pulse is output to the head control unit 42 every time the carriage 109 moves and reaches the drawing position. When receiving the drawing position pulse, the head controller 42 drives the liquid discharge head 2 to discharge the solution onto the substrate 1.

FIG. 8 is a timing chart showing the output timing of the drawing position pulse.
In FIG. 8, the address and data (RAM) of the RAM 300 represent the address and data of the RAM 300 and represent how the round-trip 2-bit data written in the RAM 300 is written. Also, the drawing position pulse in FIG. 8 is a pulse signal that gives drawing timing to the head controller 42. When the carriage 109 moves, corresponding bits are selected in the forward direction and the backward direction as shown in FIG. A pulse output can be obtained.

  Incidentally, the output timings of the forward direction pulse and the backward direction pulse shown in FIG. 8 do not match. This is because even if the liquid discharge head discharges droplets at the same position in the scanning direction, the landing position on the substrate depends on whether the moving direction of the liquid discharge head at that time is the forward direction or the return direction. Because it is different. That is, the liquid droplets ejected when the liquid ejection head moves in the forward direction shifts from the ejection position to the forward direction before landing on the substrate, and conversely, the liquid droplets ejected when moving in the backward direction are , It will shift to the return direction. For this reason, the timing of the drawing position pulse is set so that the droplet discharge position differs between when moving in the forward direction and when moving in the backward direction.

  FIG. 8 illustrates an example of bidirectional drawing in which the liquid ejection head performs drawing both in the forward path and in the backward path, and the timing of the drawing position pulse has been described. However, drawing is performed only in the forward path direction. In the case of one-way drawing, all the return path bits may be set to zero. In this case, the drawing position pulse is not output when the carriage is moving in the backward direction. In FIG. 8, for convenience, the data in the RAM 300 and the drawing position pulse are described only for one set of reciprocation. However, when there are a plurality (m) of liquid ejection heads 2 as in this embodiment, or when there are a plurality of nozzle rows (n rows) in the liquid ejection head 2, the number of data bits in the RAM 300 is increased. Data for m sets or n columns may be generated.

[4. Materials used]
[4-1. Base material]
As the substrate 1 used in the present invention, a substrate having a planar shape such as a film shape, a sheet shape, or a plate shape can be used. However, the present invention is not limited to this, and if a circuit pattern can be formed by an inkjet method. Even those having a curved surface shape can be used. Moreover, since the base material 1 includes a step of firing when forming the circuit pattern layer, it is particularly preferable that the base material 1 is made of a material having excellent heat resistance. For example, as the substrate 1, ceramics obtained by sintering alumina, silica, or the like, or a thermoplastic resin film such as a polyester film, an aromatic polyamide film, or a polyimide film can be used. Moreover, it is also possible to configure the woven fabric or nonwoven fabric made of glass fiber, polyester fiber, or aromatic polyamide fiber by impregnating and curing a thermoplastic resin or an epoxy resin into a sheet shape. Furthermore, it is also possible to use a plate-like material such as a glass epoxy laminated plate used for a normal circuit board, or a permeable substrate, paper or cloth. The substrate used in the present invention is preferably a hydrophilic substrate. In particular, a solution that has been surface-treated to the extent that a solution that will be described later that has landed on the base material does not spread due to the surface tension of the solution is preferable. Moreover, even if it is a base material with water repellency, what is necessary is just the surface treatment similar to the above.

[4-2. Conductive solution and insulating solution]
Hereinafter, the conductive solution and the insulating solution used in this embodiment will be described.
The conductive solution used in this embodiment contains water and a conductive material. As water used for the preparation of the conductive solution according to the present invention, water from which industrial water is used as a raw material and from which cations and anions have been removed by deion exchange treatment is preferable. The amount of water in the conductive solution is determined in a wide range depending on the ratio or the characteristics required of the conductive solution, but generally in the range of 10 to 98% by weight with respect to the conductive solution. Particularly preferred is the range of 40 to 90% by weight.

  The conductive material used for the conductive solution is, for example, metal ultrafine particles having an average particle diameter of 1 to 100 nm or less prepared using laser ablation. Examples of the ultrafine metal particles include ITO (indium tin oxide) and SnO2 (tin oxide).

  The insulating solution used in the present invention contains water, an insulating material, and a second component. The second component is an alkaline aqueous solution. When contacted with a conductive material used for the conductive solution, interfacial aggregation occurs in the contact region due to the aggregation precipitation reaction at a pH difference, and the conductive solution and the insulating solution bleed. Each solution is present separately from each other. Moreover, this 2nd component is a substance volatilized by the post-processing thermosetting process. Examples of water used for the insulating solution include the water used for the conductive solution described above.

  An arbitrary polymer is mentioned as a substance used as a 2nd component. As an example of an arbitrary polymer, an anionic water-soluble polymer, a volatile amine, or the like can be used. Specific examples of the second component include an ammonium salt as the anionic water-soluble polymer, and ammonium hydroxide as the volatile amine. Moreover, a nonionic polymer is mentioned as an insulating material. As a specific example of the nonionic polymer, a solder resist mainly composed of an epoxy resin or the like can be used.

[5. Circuit pattern forming method]
(First embodiment)
FIGS. 9A to 9H are schematic process diagrams for explaining a circuit pattern forming method according to the first embodiment of the present invention. In the first embodiment, the liquid discharge head 2 as shown in FIG. 2 is used. Further, in the conductor nozzle row 30a, the two adjacent large dots 12 formed on the substrate and the discharged large droplets 10 need to contact each other, so that the two large dots as shown in FIG. Large droplets 10 having a diameter larger than the interval between the dots 12 can be discharged.

First, the first discharge process will be described.
As shown in FIG. 9A, the liquid ejection head 2 is moved to one end (left end in the figure) of the base material 1 that is the drawing start position. Then, as shown in FIGS. 9A and 9B, the large liquid droplet 10 is discharged from the large nozzle 20 while moving the liquid discharge head 2 in the forward direction in the main scanning (from left to right in the figure). And land on the substrate 1. In this first ejection step, as shown in FIG. 9C, the droplets 10 are ejected so that the large dots 12 formed by landing on the substrate 1 do not overlap each other. Each large dot 12 formed on the substrate 1 in this way is formed at a predetermined position on the substrate 1 without spreading due to the surface tension of the insulating solution. Therefore, a gap 17 is formed between adjacent large dots 12 and 12 discharged onto the substrate 1 in the first discharge step, as shown in FIG. 9C.

Next, the second discharge process will be described.
After the liquid large dots 12 are formed on the substrate 1 by the first discharge process described above, the liquid discharge head 2 is immediately moved back to the drawing start position (the left end of the substrate 1). Then, as the second discharge step, as shown in FIGS. 9D and 9E, the large dots 12 and 12 formed adjacent to the substrate 1 while moving the liquid discharge head 2 in the forward direction again. A large droplet 10 of the insulating solution is discharged into the gap 17. This discharge is performed before the large dots 12 on the substrate 1 change from a liquid to a gel, that is, before solidification (gelation). For this reason, as shown in FIG. 9F, when the large dots 12 and the large droplets 10 of the insulating solution come into contact with each other, the two attract each other and mix. As a result, as shown in FIG. 9G, the large droplet 10 and the two large dots 12 are combined to form a flat and substantially uniform linear pattern 15. Then, by heating and fixing the substrate 1 with a heater, an insulating pattern 16 made of a flat and uniform thin film is formed as shown in FIG.

  In the second ejection step, since the two large dots 12 and the large droplets 10 need to contact each other, the gap between the large dots 12 formed on the two substrates as shown in FIG. The diameter D of the large droplet 10 needs to be larger than 17.

  After the insulating pattern is formed as described above, the conductive solution is discharged from the liquid discharge head 3 to similarly form the conductive pattern. This conductive pattern is formed in the same manner as the insulating pattern according to the procedure shown in FIGS. 9A to 9H, whereby a flat and uniform thin conductive pattern can be formed.

In FIG. 9, the discharge of the large droplet 10 is started from the left end of the drawing, but the discharge may be started from the reverse direction (the right end of the drawing). Further, while the relative movement between the liquid ejection head 2 and the substrate 1 is reciprocated once, the first ejection process may be performed in the forward path and the second ejection process may be performed in the backward path. Patterns can be formed at high speed by reciprocating discharge.
Here, the definition of the gap in this specification will be described. FIG. 11 is a schematic view of the arrangement of dots formed on the substrate 1 as viewed from above. In FIG. 11A, the large dots 12 are formed in parallel so that the dots do not overlap each other. Except where the large dots 12 are formed, that is, the portion surrounded by the dots and the portion sandwiched between the dots are the gaps 17. FIG. 11B shows an example in which the gap 17 is filled with the large droplet 10 having the same size as the droplet used in the first discharge process. When the large droplet 10 lands in a gap such as the interval A, contact with the adjacent large dot 12 that has already landed on the substrate 1 occurs, and the liquid mixture as shown in FIG. Wake up. In addition, when filling a portion where the distance between two adjacent large dots 12 is narrow, such as the distance B in FIG. 11C, small droplets 11 smaller in size than the droplets used in the first ejection step are used. It may be discharged.

  Although illustration is omitted, the formation of the insulating pattern and the conductive pattern in the second and subsequent layers may be performed by the same method as the pattern formation in the first layer.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
FIGS. 12A to 12J are schematic process diagrams for explaining a circuit pattern forming method according to the second embodiment.

In the second embodiment, the insulating pattern and the conductive pattern are formed simultaneously.
First, the first discharge process will be described.
As shown in FIG. 12A, the liquid ejection heads 2 and 3 are moved to one end (left end in the figure) of the base material 1 which is the drawing start position. Then, as shown in FIGS. 12A and 12B, large liquid droplets 10a are discharged while moving the liquid discharge heads 2 and 3 in the forward direction in the main scan (from left to right in the figure). Land on material 1. At this time, as shown in FIG. 12C, the droplets 10a are discharged so that the large dots 12a formed on the substrate 1 do not overlap each other. Thus, each large dot 12a formed on the base material 1 is formed at a predetermined position on the base material 1 without being spread by the surface tension of the conductive solution. Therefore, a gap 17a is formed between adjacent large dots 12 and 12 discharged onto the substrate 1 in the first discharge step, as shown in FIG. 9C.

  Subsequently, as shown in FIG. 12 (d), the large droplet 10 b of the insulating solution is ejected from the large nozzle 20 of the large nozzle row 30 a of the liquid ejection head 3 and landed on the substrate 1. Further, as shown in FIG. 12D, the large liquid droplet 10b is discharged while moving the liquid discharge heads 2 and 3 in the forward direction. The ejection of the droplet 10b of the insulating solution is also performed so that the large dots 12b formed after landing on the substrate 1 do not overlap each other, as shown in FIG. Accordingly, a gap 17b is formed between the adjacent droplets 10b and 10b.

Next, the second discharge process will be described.
After the liquid large dots 12a and 12b are formed on the substrate 1 by the first discharge process described above, the liquid discharge heads 2 and 3 are immediately moved back to the drawing start position (the left end of the substrate 1). Then, before the large dots 12a and 12b on the substrate 1 change from a liquid to a gel, that is, before solidification (gelation), as shown in FIG. A large droplet 10a of a conductive solution is discharged into a gap 17a between the large dots 12a and 12a formed above. Further, the large droplet 10b of the insulating solution is similarly discharged into the gap 17b between the large dots 12b and 12b formed on the substrate 1 while moving the liquid discharge heads 2 and 3 in the forward direction. (Refer to FIG. 12 (f) and (g)).

  At this time, since the large dots 12a and 12b formed in the first ejection step are in a state before gelation, when the large dots 12a and the large liquid droplet 10a of the conductive solution come into contact with each other, FIG. In this way, the large dots 12a and the large droplets 10b come into contact with each other and are attracted and mixed together. As a result, a linear pattern 15a in which the large droplet 10a and the two large dots 12a are combined is formed (see FIG. 12H). Also, as shown in FIG. 12 (h), the large droplet 10b of the insulating solution comes into contact with the large dot 12b, and they are attracted to each other to be mixed and united. As a result, a thin linear pattern 15b having a substantially uniform thickness is formed (see FIG. 12I). Then, by heating and fixing the substrate 1 with a heater, conductive patterns 16a and insulating patterns 16b made of a flat and uniform thin film are formed as shown in FIG. 12 (j).

  12A to 12J, the case where a single-layer substrate is formed has been described. However, a multilayer circuit substrate can also be formed by stacking such conductive patterns 16a and insulating patterns 16b.

  Needless to say, the present invention is not limited to conductive patterns and insulating patterns, but can be applied to any pattern forming method using a material that can be discharged with a liquid, including a semiconductor material.

FIG. 13 is a diagram illustrating a process of forming a three-layer circuit board as a multilayer circuit board.
First, when forming the first layer, as shown in FIG. 13A, an insulating solution and a conductive solution are used to form large dots as in the first and second ejection steps described above. Large droplets are ejected into the gaps between the large dots and the respective patterns are formed to obtain a substantially uniform thin film thickness. Thereafter, heat treatment is performed to fix the first layer as shown in FIG.

  Next, a second layer is formed on the first layer. As shown in FIG. 13C, the first discharge step and the second discharge step are performed on the fixed first layer in the same manner as the first layer to form an insulating pattern and a conductive pattern. Thereafter, the second layer is fixed by heat treatment (see FIG. 13D).

The third layer is formed by patterning by the same method as the first and second layers (see FIG. 13 (e)), and heat treatment is performed, as shown in FIG. 13 (f). To fix.
Even when a three-layer circuit board was formed in this manner, a substantially uniform thin film thickness could be obtained for each layer.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
FIG. 14 is a bottom view schematically showing nozzle rows arranged on the orifice surface of the liquid discharge head used in the third embodiment, and FIGS. 15A to 15F are circuit patterns in the same embodiment. It is a schematic process drawing for demonstrating a formation method.
In the third embodiment, the inter-process time from the first discharge process to the second discharge process is shortened. For this reason, even when the solution to be used (insulating solution and conductive solution) has a characteristic that the change time from liquid to gel is short, the large dots formed in the first discharge step and the second discharge step It becomes possible to mix the discharged large droplets.

  As shown in FIG. 14, the liquid ejection head 4 is provided with two large nozzles 20 that eject large droplets and two large nozzle rows 30 b and 30 c in which the large nozzles 20 are arranged at equal intervals. Although not shown here, also in the third embodiment, similarly to the above embodiments, the liquid discharge head 4 that discharges the insulating solution and the conductive solution discharge having the same configuration as this. A liquid discharge head is juxtaposed.

Hereinafter, a circuit pattern forming process according to the third embodiment will be described with reference to FIGS. Note that the case where an insulating solution is discharged will be described as an example here, but the same method can be applied to a case where a conductive solution is discharged.
When using an insulating solution having a long fixing time (time to change from liquid to gel), once the liquid ejection head starts drawing as in the first and second embodiments. What is necessary is just to perform a 2nd discharge process, after moving to a position (left end of the base material 1). However, when this method is applied to a solution having a characteristic of a short fixing time, the large dots ejected in the first ejection process are solidified between the first ejection process and the second ejection process, There is also a possibility that the droplets discharged in both processes do not mix. Therefore, in the third embodiment, by performing the first discharge step and the second discharge step in the same scan of the liquid discharge head 4, before the dots formed in the first discharge step are solidified, Droplets are discharged in the second discharge step.

  That is, first, as shown in FIG. 15A, the liquid ejection head 4 is moved to the left end (left side in the drawing) of the base material 1, which is the drawing start position. Then, as shown in FIGS. 15 (a) and 15 (b), the large liquid droplet 10 is discharged while moving the liquid discharge head 4 in the forward direction (from left to right in the figure), and onto the substrate 1. Let it land. At this time, the adjacent large dots 12A and 12B formed on the substrate 1 are discharged so as not to overlap each other. This discharge process is the first discharge process.

  Next, when the large dot 12B of the insulating solution is formed on the substrate 1 in the same scanning, a large droplet of the insulating solution is immediately discharged from the nozzle 20 of the nozzle row 30c located rearward in the scanning direction (see FIG. 15 (c)), landing is made between the two large dots 12A and 12B (FIG. 15 (d)). This is the second ejection step in the third embodiment. That is, in this embodiment, as in the first and second embodiments described above, the liquid discharge head 4 is moved to the discharge start position (left end of the substrate 1) and then the second discharge step is performed. Instead, as shown in FIG. 15C, the second ejection process is started immediately from the position where the first ejection process is completed. For this reason, it is possible to land the large liquid droplet 10 with almost no time difference after the large dots 12A and 12B are formed. Therefore, even if the previously landed large dots 12A and 12B are easy to solidify, the large droplet 10 can be landed before these dots solidify (gel). Then, as shown in FIG. 15D, when the large droplets 10 of the insulating solution come into contact with the large dots 12A and 12B, they are attracted and mixed with each other at the contact portion (see FIG. 15E), and then Large droplets 10 and two large dots 12 merge. As a result, a thin linear pattern 15 having a substantially uniform thickness can be formed (see FIG. 15F).

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
FIG. 16 is a bottom view schematically showing nozzle rows arranged on the orifice surface of the liquid discharge head used in the fourth embodiment, and FIGS. 17A to 17F are circuit patterns in the same embodiment. It is a schematic process drawing for demonstrating a formation method.
As shown in FIG. 17, in the fourth embodiment of the present invention, small droplets are ejected in the gap between the large dots 12A and 12B formed on the substrate 1 in the first ejection step in the second ejection step. To do. As a result, even when the gap between the large dots 12A and 12B is small, the large dots 12A and 12B and the small droplet 11 can be mixed while preventing the droplets from overflowing and spreading.

  In the fourth embodiment, a liquid discharge head 5 as shown in FIG. 17 is used. The liquid ejection head 5 shown in FIG. 17 includes a large nozzle row 30d in which large nozzles 20 that eject large droplets are arranged at equal intervals, and a small nozzle row in which small nozzles 21 that eject small droplets are arranged at equal intervals. 31 are arranged in parallel. Although not shown here, also in the fourth embodiment, similarly to the above embodiments, the liquid discharge head 5 that discharges the insulating solution and the conductive solution discharge structure having the same configuration as this. A liquid discharge head is juxtaposed.

Hereinafter, a circuit pattern forming process according to the fourth embodiment will be described with reference to FIG.
A method for changing the size of the droplets used in the first and second ejection steps according to the fourth embodiment of the present invention will be described. In the fourth embodiment, the case where an insulating solution is used will be described as an example. However, even when a conductive solution is used, the same method can be used.

  First, as shown in FIG. 17A, the liquid ejection head 5 is moved to the left end (left side in the drawing) of the base material 1 that is the drawing start position, and the large droplet 10 of the insulating solution is moved to the liquid ejection head 5. It discharges from the large nozzle 20 of the large nozzle row 30b and is landed on the substrate 1. As shown in FIG. 17 (b), as the first discharge step, large droplets 10 are discharged and landed on the substrate 1 while moving the liquid discharge head 5 in the scanning direction (from left to right in the figure). Let At this time, the adjacent large dots 12A and 12B formed on the substrate 1 are discharged so as not to overlap each other. This discharge process is the first discharge process.

Next, the second discharge process will be described.
Also in the fourth embodiment, similarly to the third embodiment, the second discharge process is performed without moving the liquid discharge head 5 to the drawing start position (the left end of the substrate 1). That is, as shown in FIG. 17C, when the large dots 12A and 12B are formed in the first ejection step, the small droplets 11 of the insulating solution are placed in the gaps between the two dots and the small nozzles 21 of the small nozzle row 31. Discharge from. The small droplets 11 are in contact with the large dots 12A and 12B (see FIG. 17D), and the large dots 12A and 12B and the droplet 11 are attracted and mixed with each other at the contact portion (FIG. 17E). After that, the small droplet 11 and the two large dots 12 merge. As a result, a thin linear pattern 15 having a substantially uniform thickness is formed (see FIG. 17F).

  As described above, in the fourth embodiment, the liquid droplets discharged in the second discharge step in accordance with the narrow gap 17 formed between the large dots 12A and 12B formed in the first discharge step. Was made smaller. For this reason, it is possible to prevent the liquid droplet from overflowing and spreading due to the combination of the liquid droplet and the large dots 12A and 12B, and it is possible to form a circuit pattern more accurately.

It is a perspective view which shows schematic structure of the circuit pattern formation apparatus used by embodiment of this invention. FIG. 3 is a bottom view schematically showing nozzle rows arranged on an orifice surface of a liquid discharge head used in the first embodiment of the present invention. It is a block diagram which shows roughly the whole structure of the control system provided in the circuit pattern formation apparatus in embodiment of this invention. It is a figure which shows the output signal of the linear encoder in embodiment of this invention. It is a block diagram showing an example of a circuit of a liquid discharge head position detection part in an embodiment of the present invention. 6 is a timing chart showing output signals of respective units in the circuit shown in FIG. 5. FIG. 4 is a block diagram of a drawing position signal generator shown in FIG. 3. 6 is a timing chart showing the output timing of a drawing position pulse in the embodiment of the present invention. It is a schematic process diagram for explaining a circuit pattern forming method in the first embodiment of the present invention. It is a figure which shows the relationship between the gap of the adjacent dot formed on the board | substrate in the 1st Embodiment of this invention, and the diameter of the droplet discharged to the gap. FIG. 11 is a schematic view of the arrangement of dots formed on the substrate 1 as viewed from above. It is a schematic process drawing for demonstrating the circuit pattern formation method in the 2nd Embodiment of this invention. FIG. 10 is a schematic process diagram for explaining a method of forming a three-layer circuit board as a multilayer circuit board according to the second embodiment of the present invention. FIG. 10 is a bottom view schematically showing nozzle rows arranged on an orifice surface of a liquid ejection head used in a third embodiment of the present invention. It is a schematic process drawing for demonstrating the circuit pattern formation method in the 3rd Embodiment of this invention. It is a bottom view which shows typically the nozzle row arrange | positioned at the orifice surface of the liquid discharge head used for the 4th Embodiment of this invention. It is a schematic process drawing for demonstrating the circuit pattern formation method in the 3rd Embodiment of this invention. In the conventional circuit pattern formation, it is a figure which shows the state in which the liquid puddle, disconnection, and short circuit generate | occur | produced. It is a figure which shows the conventional circuit pattern formation method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2, 3, 4, 5 Liquid discharge head 10, 10a, 10b Large droplet 11 Small droplet 12, 12a, 12b Large dot 15, 15a, 15b Linear dot pattern 16, 16a, 16b, 19 Fixing 17 Conductive pattern 17 Clearance 18 Fixed insulation pattern 20 Large nozzle 21 Small nozzle 30a, 30b, 30c, 30d Large nozzle row 31 Small nozzle row 45 Buffer memory 46 Mechanism unit 50 Memory control unit 101 CR linear motor 102 LF linear motor 103 Stage 106, 107 Origin sensor 109 Carriage 111, 112 Linear encoder

Claims (9)

A circuit pattern forming method for forming a circuit pattern by discharging a liquid for forming a circuit pattern onto a substrate using a liquid discharging means,
A first discharge step of discharging a large droplet of liquid from the first nozzle and forming a plurality of liquid first dots with a gap on the substrate;
To eject the large droplet smaller small droplets from the second nozzle before the first dot of the liquid is solidified, the liquid form of the second between the first dot of the liquid on the substrate A second ejection step of further forming dots and forming a liquid circuit pattern flattened by mixing the liquid first dots and the liquid second dots ;
A fixing step of solidifying the liquid circuit pattern by heating ;
A circuit pattern forming method comprising:   A circuit pattern having a laminated structure is formed on the circuit pattern formed on the base material by further repeating the first discharge step, the second discharge step, and the fixing step. Item 2. The circuit pattern forming method according to Item 1.   The diameter of the droplet discharged in the second discharge step is larger than a gap between dots to be connected formed on the base material in the first discharge step. Circuit pattern forming method.   The liquid for forming the circuit pattern includes a conductive solution containing conductive fine particles that form a conductive pattern and an insulating solution that forms an insulating pattern. The circuit pattern formation method as described in 2. A circuit pattern forming apparatus for forming a circuit pattern by forming a plurality of liquid dots on the base material by discharging a liquid for forming a circuit pattern onto the base material by liquid discharging means,
Moving means for moving the liquid discharge means relative to the substrate;
Detection means for detecting a relative position between the liquid ejection means and the substrate;
Based on the relative position between the liquid ejecting means and the substrate detected by the detecting means and the data forming the circuit pattern, a large liquid droplet is ejected from the first nozzle, and the liquid first liquid is ejected to the substrate . after forming a dot with a gap, of the liquid in which the formed in the substrate by ejecting large liquid droplets smaller than the small droplet from the second nozzle before the first dot of the liquid is solidified first liquid between the dots second dot further formed to the first dot and the second dot and that is miscible flattened control means for forming a circuit pattern of the liquid the liquid of the liquid When,
A circuit pattern forming apparatus comprising: The liquid ejecting means ejects liquid while scanning relative to the substrate;
The control means is configured to drop liquid droplets from the liquid ejection means so as to fill the gap between the liquid dots to be connected and the scanning direction of the liquid ejection means when forming the liquid dots on the substrate with a gap. The circuit pattern forming apparatus according to claim 5, wherein a scanning direction of the liquid ejecting unit when ejecting is the same direction. The liquid discharge means discharges liquid while reciprocally scanning with respect to the base material,
The control means scans the liquid ejection means when forming liquid dots on the substrate with a gap, and the liquid when ejecting liquid droplets so as to fill the gap between liquid dots to be connected. 7. The circuit pattern forming apparatus according to claim 5, wherein the scanning of the discharge means is performed by reciprocating scanning. The liquid ejection means is configured by sequentially arranging a plurality of nozzle rows in which a plurality of nozzles that eject droplets are arranged along a direction intersecting the scanning direction along the scanning direction,
Scanning of the liquid ejecting means when forming liquid dots on the substrate with a gap, and scanning of the liquid ejecting means when ejecting liquid droplets so as to fill the gap between the liquid dots to be connected 7. The circuit pattern forming apparatus according to claim 6, wherein the scanning is the same. The nozzle row includes a large nozzle row composed of large nozzles that eject large droplets, and a small nozzle row composed of small nozzles that eject small droplets having a smaller diameter than the large droplets,
The control means discharges a large droplet from the large nozzle to the substrate to form a large liquid dot with a gap, and fills the gap between the large liquid dots to be connected from the small nozzle. 9. The circuit pattern forming apparatus according to claim 7, wherein a small droplet is ejected.

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