JP4961162B2 - Electrical connector and cartridge - Google Patents

Description

The present invention relates to an electrical connection body used for multilayer wiring and the like, a method for forming an electrical connection body, and a cartridge.

In order to increase the mounting density of wiring, wiring boards are stacked and used. Further, the through-hole formed in the substrate has a so-called high aspect ratio in which the diameter in the height direction becomes long with respect to the diameter while the diameter becomes as small as several μm. For this reason, there is a problem that the metal paste or the like cannot be filled in the through hole, and disconnection occurs in the through hole.

Although the present invention has been made in view of the above-mentioned problems, when a metal ultrafine particle dispersion is filled in a through hole formed in a substrate and wiring between the deposited substrates is performed, several μm Even if the length of the through hole in the height direction is increased with respect to the fine through hole diameter, the metal ultrafine particle dispersion can be filled in the through hole, thereby preventing disconnection in the through hole. An object of the present invention is to provide an electrical connection body and a method for forming the electrical connection body.

In order to solve the above-mentioned problems, the electrical connection body of the present invention deposits the droplets by ejecting the droplets toward the substrate surface from a nozzle having a diameter of about 5 μm or less, preferably about 1 μm or less of the droplet discharge device. Rm1, the solidified diameter of the growth origin droplet layer on the preceding landing droplet layer landed on the substrate surface of the droplet deposition body, When the maximum solidified diameter of the droplet deposition layer formed on the growth origin droplet layer is Rm2, the ratio of Rm1 and Rm2 is 2: 1 to 1: 1.

In addition, the electrical connection body of the present invention ejects droplets from a nozzle having a diameter of about 5 μm or less, preferably about 1 μm or less, into a through hole formed in a substrate, and deposits the droplets. An electrical connection body comprising a droplet deposit formed in this manner, wherein the growth origin droplet layer of the droplet deposit includes a tip.

The aspect ratio of the droplet deposit is 1 or more, and the maximum diameter of the droplet deposit is 3 μm or less.

It has a tip at the top of the droplet deposition layer of the droplet deposition body.

The liquid droplet is a liquid in which ultrafine metal particles are dispersed.

The droplet is characterized by containing a conductive filler in a liquid in which ultrafine metal particles are dispersed.

Further, according to the method for forming an electrical connection body of the present invention, a step of patterning and forming a bank for preventing spread for discharging the bank to prevent the catalyst from spreading to the side, and a catalyst layer is formed in the bank. And a step of discharging a metal ultrafine particle dispersion onto the catalyst layer to deposit a metal ultrafine particle dispersion.

Further, the method for forming an electrical connection body according to the present invention includes a step of patterning a deposit on a substrate, a step of embedding a resin in the deposit to form a resin layer, and the deposit on a resin layer. Coating the liquid repellent, covering the deposit, irradiating the liquid repellent on the deposit with a laser to remove the liquid repellent and exposing the deposit, and applying the metal ultrafine particle dispersion on the exposed deposit And a step of performing.

The method for forming an electrical connection body according to the present invention includes a step of discharging a droplet onto a substrate surface to form a fine pattern made of ultrafine metal particles, a step of coating a liquid repellent on the fine pattern, Irradiating the liquid repellent with a YAG laser; irradiating the YAG laser to evaporate the liquid repellent to form holes in the substrate surface; filling the holes with a metal ultrafine particle dispersion; and And a step of applying a metal ultrafine particle dispersion.

The method for forming an electrical connection body according to the present invention includes a step of inserting a nozzle of a droplet discharge device into a recess provided in a substrate, and discharging the droplet toward a sidewall of the recess by tilting the nozzle by a predetermined angle. And depositing droplets on the side walls, and depositing a conductive material in the recess.

The method for forming an electrical connection body according to the present invention further includes a step of cutting the bottom surface of the substrate on which the conductive material is deposited.

The present invention further provides a cartridge that accommodates droplets constituting the electrical connection body and is detachably provided in the droplet discharge device.

By reducing the volume of the droplet deposit body as the electrical connection body, the electrical connection body can be formed with a small amount of material input.
It is possible to fill the through hole with the metal ultrafine particle dispersion, and thus it is possible to prevent disconnection in the through hole.
By filling from the central portion in the through hole, the mixing of bubbles can be minimized, and satisfactory filling can be realized.

By having the deposition tip, the landing accuracy of the droplet can be improved, and the filling can be efficiently performed from the central portion.
By using a liquid in which ultrafine metal particles are dispersed, stable discharge can be performed even with a small nozzle diameter, and a deposit having uniform characteristics can be manufactured.
By containing the conductive filler, it contributes to the volume change and deformation reduction during solidification of the liquid, and the strength improvement of the deposit, so that the electrical connectivity is improved.

By providing a bank in advance in the catalyst, the outer shape and film thickness can be made uniform, and stable electrical characteristics can be obtained.
By using the upper surface of the deposit or itself as a liquid repellent removal pattern, a photolithography process and a mask become unnecessary, and effective use of resources and energy saving can be realized.
An electrical connector can be formed without applying a conductive material to the entire surface of the through hole, and the material can be used more efficiently than in the past.
By adopting the cartridge system, it is possible to efficiently deposit ultrafine metal particles according to the length of the wiring, the number of through holes, and the depth.

FIG. 1 is a schematic view of a droplet discharge device used in an example of an embodiment of the present invention.
The droplet discharge device 10 has a nozzle 12 of a droplet discharge device having pores having a diameter of about 5 μm or less, preferably about 1 μm or less, and discharges droplets from the nozzle 12 toward the substrate to land on the substrate surface. When the diameter of the solidified growth origin droplet on the preceding landing droplet is Rm1, and the maximum diameter of the solidified growth termination droplet on the top layer of the droplet deposit is Rm2, the ratio of Rm1 to Rm2 is Voltage / frequency control means 16 for controlling the voltage and / or frequency applied to the nozzle 12 so as to be 2: 1 to 1: 1.

In FIG. 1, a droplet discharge device 10 is attached to and detached from a nozzle 12, an electrode 14 for applying a voltage to the nozzle 12, a control device 16 for controlling the frequency and voltage applied to the nozzle 12, and the nozzle 12. And a cartridge 18 that is freely inserted and accommodates a droplet. The applied voltage of the nozzle 12 depends on the ink material, but the peak-to-peak voltage is about 250 V to 800 V, and the applied frequency is about 10 Hz to 1 kHz. When nano paste is used as the ultrafine metal particle dispersion for this ink material, the frequency is more preferably 30 Hz to 200 Hz.
The nozzle 12 has pores having a diameter of about 5 μm or less, preferably about 1 μm or less. The cartridge 18 is detachably attached to the droplet discharge device 10. The nozzle 12 is filled with a metal ultrafine particle dispersion or the like, and the metal ultrafine particles are charged.

Suitable types of ink materials include metals (gold, silver, copper, iron, nickel, cobalt, platinum, palladium, and oxides thereof), carbon-based materials (carbon nanotubes, fullerenes such as C60, nanocarbon, and nanodiamonds. ), Functional molecules such as conductive molecules or semiconductor molecules having a conjugated bond, resin (acrylic resin, silicon resin, alkyd resin, epoxy resin, urethane resin, polyester resin, photocurable resin, thermosetting resin, thermoplasticity Resin) and solvent types include tetradecane, decalin, decane, decanol, water, butyl carbitol and other high-boiling organic solvents for printing such as AF7. The low boiling point solvent has a high drying property, and thus is effective for applications such as the present invention, but causes problems such as nozzle clogging. On the other hand, nozzle clogging is unlikely to occur with a high-boiling solvent, and it is possible to maintain discharge stably for a long time.

The nozzle 12 is provided with a low-conductance flow path in order to achieve an ultrafine droplet size, or the nozzle itself has a low conductance. Therefore, it is preferable to use a glass capillary for the nozzle 12, but it is also possible to use a conductive material coated with an insulating material. The nozzle 12 is made by a capillary puller using a glass tube.

The nozzle 12 is not limited to a capillary tube, and may be a two-dimensional pattern nozzle formed by fine processing. When glass having good moldability is used, the nozzle 12 cannot be used as an electrode, and therefore a metal wire (tungsten wire) is inserted into the nozzle 12 as an electrode. An electrode may be formed in the nozzle 12 by plating. When the nozzle itself is formed of a conductive material, an insulating material is coated thereon.

  The lower limit of the nozzle diameter is preferably 0.01 μm, and the upper limit of the nozzle diameter is that the upper limit of the nozzle diameter when the electrostatic force exceeds the surface tension is 5 μm, and the local electric field The upper limit of the nozzle diameter when the discharge condition is satisfied depending on the strength is preferably 5 μm or less. In particular, in order to more effectively use the local electric field concentration effect, the nozzle diameter is desirably in the range of 0.01 to 1 μm.

Since the ultrafine nozzle 12 uses an ultrafine capillary, the liquid level of the metal ultrafine particle dispersion in the nozzle is located inside the nozzle tip surface by capillary action. Therefore, in order to facilitate the discharge of the ultrafine metal particle dispersion, a pressure regulator (not shown) may be used to adjust the liquid surface to be positioned near the nozzle tip by applying hydrostatic pressure to the pressure tube. The pressure at this time depends on the shape of the nozzle 12 and may not be applied, but is about 0.1 to 1 MPa in consideration of a reduction in driving voltage and an improvement in response frequency. When an excessive pressure is applied, the solution overflows from the tip of the nozzle, but because the nozzle shape is tapered, the solution moves quickly to the holder side without being limited to the nozzle end due to the action of surface tension.

The role of the pressure regulator is to push the fluid out of the nozzle by applying a high pressure, but it is particularly useful to adjust the conductance, fill the nozzle with a metal ultrafine particle dispersion, and remove the nozzle clog. It is valid. In addition, the position of the liquid surface is controlled, which is effective for forming a meniscus. Moreover, the force which acts on the metal ultrafine particle dispersion liquid in a nozzle is controlled by giving a phase difference with a voltage pulse, and also plays the role which controls a micro discharge amount.

The cartridge 18 contains the following amount of ultrafine metal particle dispersion.
That is, when droplets are ejected from the nozzle 12 of the droplet ejection apparatus 10 having pores having a diameter of about 5 μm or less, preferably about 1 μm or less toward the substrate, the droplets are continuously landed on the substrate surface in the longitudinal direction. In addition, the amount of droplets is obtained in advance from the length of a pattern formed of a droplet deposit formed so that the degree of overlap between adjacent droplets is several percent or less, and the obtained amount of paste material is stored. . Note that the storage amount of the cartridge 18 may be n times (n is an integer) the amount obtained by measurement.

Or, in a droplet deposit formed by depositing landed droplets, a droplet deposit formed by depositing m droplets in consideration of the spread of droplets after landing on the substrate surface The amount of liquid droplets is obtained in advance from the height, and the obtained amount of paste material is stored. Note that the storage amount of the cartridge 18 may be n times (n is an integer) the amount obtained by measurement.

Alternatively, when the droplet discharge device discharges a droplet from the nozzle 12 of the droplet discharge device 10 having pores having a diameter of about 5 μm or less, preferably about 1 μm or less and the nozzle 12 toward the substrate, The droplets required to form a strip made of a droplet deposit formed by landing the droplets so that the overlapping degree of the droplets that are adjacent to each other in the longitudinal direction is 40% to 80%. An amount is obtained in advance, and a cartridge 18 containing n times (n is an integer) of the obtained amount of paste material is provided.

FIG. 2 is a schematic view of a droplet discharge device 10 according to another embodiment of the present invention.
An electrode 20 is provided on the side surface of the nozzle 12, and a controlled voltage is applied to the liquid in the nozzle 12. This electrode 20 is an electrode for controlling the electrowetting effect. When a sufficient electric field is applied to the insulator constituting the nozzle 12, it is expected that the electrowetting effect will occur even without the electrode 20. However, by controlling more positively using the electrode 20, it also serves as a discharge control.
When the nozzle 12 is made of an insulator, its thickness is 1 μm, the nozzle inner diameter is 2 μm, and the applied voltage is 300 V, an electrowetting effect of about 30 atmospheres is obtained. This pressure is insufficient for discharge, but is meaningful in terms of supplying the solution to the nozzle tip, and discharge can be controlled by this control electrode.

The above-described droplet discharge device 10 is characterized by the effect of concentration of the electric field at the nozzle tip and the action of the image force induced on the opposing substrate. Since the electric field strength required for ejection depends on the local concentrated electric field strength, the presence of the counter electrode is not essential. Further, the droplets separated from the nozzle 12 are given kinetic energy by the action of Maxwell stress due to the local concentrated electric field.
The scattered droplets gradually lose their kinetic energy due to air resistance. On the other hand, since the droplets are charged, a mirror image force acts on the substrate. For this reason, it is not necessary to make the substrate or the substrate support conductive or to apply a voltage to the substrate or the substrate support unlike the prior art.

The closer the distance between the nozzle 12 and the substrate is, the more the image force acts, so that the landing accuracy is improved. Considering the landing accuracy and the unevenness on the substrate, the distance between the nozzle 12 and the substrate is preferably 500 μm or less. Moreover, when there are few unevenness | corrugations on a board | substrate and a landing precision is requested | required, 100 micrometers or less are preferable and 30 micrometers or less are more preferable.

FIG. 3A to FIG. 3D are diagrams showing a deposition state of droplets ejected from the nozzle 12 of the droplet ejection device 10. In FIG. 3, reference numeral 22 denotes a substrate (FIG. 3A), and a metal ultrafine particle dispersion liquid 24 is discharged from the nozzle 12 of the droplet discharge device 10 onto the substrate 22. As the ultrafine metal particle dispersion, gold nanopaste (NPG-J) manufactured by Harima Kasei Co., Ltd. is used (FIG. 3B).
The metal ultrafine particle dispersion 24 discharged from the tip of the nozzle 12 is a local electric field due to the concentration effect of the electric field at the tip of the nozzle 12 of the droplet discharge device 10 and the action of the image force induced on the opposing substrate 22. Due to the concentration effect, a shape having the tip 26 is always formed (FIG. 3C). Thus, the droplets ejected continuously from the tip of the nozzle 12 are always ejected toward the tip 26 of the droplet shape (FIG. 3D).

The droplet discharge device 10 includes a substrate 22 that is a means for generating an electric field concentration effect and a nozzle 12 that is a liquid storage and discharge function. The means 12 may be constituted by different means. In this case, the means 22 for generating the electric field concentration effect may be constituted by needle-like electrodes, and the liquid storage / discharge means 12 may simply discharge the stored liquid. An example is shown in FIGS.

4 is a schematic view showing a state in which the needle-like electrode 30 and the nozzle 32 of the droplet discharge device are separately provided, and FIG. 5 shows a state in which the needle-like electrode 30 is provided so as to surround the nozzle 32. FIG. 6 is a schematic diagram illustrating a state in which the needle electrode 30 is disposed between the nozzle 32 and the nozzle 32.

FIG. 7A is a schematic view showing a droplet depositing body 34 formed by depositing droplets scattered from the nozzle of the droplet discharge device toward the substrate. In the figure, a droplet deposit 34 includes a preceding landing droplet layer 34a obtained by first landing on the substrate 22, a growth origin droplet layer 34b formed on the preceding landing droplet layer 34a, and a growth origin. A droplet depositing layer 34c having an uppermost end 34d formed by continuously growing the droplet layer 34b. The droplet deposits 34a, 34b, 34c and 34d in the figure are obtained by applying a predetermined constant voltage v to the nozzle at the droplet deposition time t. Rm1 and Rm2 when the diameter of the solidified growth origin droplet layer on the preceding landing droplet landed on the substrate surface is Rm1 and the maximum diameter of the solidified droplet deposition layer on the growth origin droplet layer is Rm2. The ratio is 2: 1 to 1: 1.
The diameter of the solidified growth origin droplet layer 34b is 2 μm, and the height of the droplet stack layer 34c is 400 μm or more. Therefore, the aspect ratio of the droplet stack 34 is about 200 or more.

FIG. 7B is a schematic view showing a step of forming a droplet deposit 34 formed by depositing droplets scattered from the nozzle of the droplet discharge device toward the substrate. In the figure, the preceding landing droplet 34 a lands on the surface of the substrate 22. The process of solidifying the preceding landing droplet 34a on the substrate is shown in 34a-1 to 34a-3 in FIG. 7B. The growth origin droplet 34b-1 landed on the preceding landing droplet 34a-3 is landed and solidified by a droplet having a tip and flattened. Next, a further tip 34b-2 is formed on the flattened growth origin droplet layer 34b-1. Thus, the droplet deposition layer 34c is formed by applying a predetermined constant voltage to the nozzle and discharging the droplet to land continuously on the tip 34b-2 of the growth origin droplet layer.

  The preceding landing droplet layer 34a forms a state in which electric charges are distributed almost uniformly on the surface of the substrate and are wet and spread on the substrate. The growth origin droplet layer starts growing when charges are accumulated at the growth point 34b-1 which is the tip, and the density of the charges increases and the distribution of electric lines of force changes. Here, the wetting spread (contact angle) is determined by the relationship between the surface energy of the substrate and the droplet. The surface energy difference between the substrate and the preceding landing droplet layer 34a is largely wet and spread, whereas the difference in surface energy of the growth origin droplet on the preceding landing droplet layer 34a is small and difficult to spread. Accordingly, the wetting and spreading of the growth origin droplet is suppressed.

  FIG. 7C to FIG. 7E are schematic views showing other droplet deposits. The droplet separated from the nozzle 12 is given kinetic energy by the action of Maxwell stress due to a local concentrated electric field. The shape of the droplet deposit can be varied by controlling the voltage of the droplet separated from the nozzle 12.

  In FIG. 7C, a droplet is landed on the substrate 22 to form a preceding landing droplet layer 34a, a growth origin droplet layer 34b is formed thereon, and then a liquid is deposited on the growth origin droplet layer 34b. A droplet deposition layer 34c is formed. The uppermost part 34d of the droplet deposition layer 34c has a diameter larger than the diameter of the droplet deposition layer 34c. In the voltage application to the nozzle, after a predetermined constant voltage v is applied for the first predetermined time at the droplet deposition time t, the voltage is increased to the predetermined voltage.

In FIG. 7D, a droplet is landed on the substrate 22 to form a preceding landing droplet layer 34a, a growth origin droplet layer 34b is formed thereon, and then a liquid is deposited on the growth origin droplet layer 34b. A droplet deposition layer 34c is formed. The droplet deposition layer 34c is formed in a conical shape. The voltage is applied to the nozzle by repeating a pattern in which the voltage is increased stepwise after a predetermined constant voltage v is applied for the first predetermined time at the droplet deposition time t.

In FIG. 7E, a droplet is landed on the substrate 22 to form a preceding landing droplet 34a, a growth origin droplet 34b is formed thereon, and then the first liquid is formed on the growth origin droplet layer 34b. A droplet deposition layer 34c is formed. Thereafter, the first uppermost portion 34d of the droplet deposition layer 34c has a diameter larger than the diameter of the first droplet deposition layer 34c. Further, the second droplet deposition layer 34c ′ is formed from the tip of the first uppermost portion 34d of the droplet deposition layer 34c, and the second uppermost portion 34d ′ is formed on the uppermost portion thereof. The second uppermost portion 34d 'of the second droplet deposition layer 34c' has a diameter larger than the diameter of the second droplet deposition layer 34c '. In the voltage application to the nozzle, after a predetermined constant voltage v is applied for the first predetermined time at the droplet deposition time t, the voltage is increased to the predetermined voltage. This application pattern is repeated.

FIG. 8 shows that when the catalyst is patterned on the substrate, in order to prevent the catalyst body 36 from spreading laterally and to make the droplet stack 34 have a predetermined diameter, the catalyst 36 is prevented from spreading before discharging. This shows how the bank 38 is patterned at a predetermined interval. Thereafter, the metal ultrafine particle dispersion is discharged onto the catalyst 36 from the droplet discharge device 10 to deposit the metal ultrafine particle dispersion 24.

FIG. 9 is a schematic view showing a state in which the insulator 42 is provided on the uppermost portion of the droplet depositing body 34 using the droplet discharge device 10. FIG. 10 is a schematic view showing a state in which an insulator 42 is provided around the side portion of the droplet depositing body 34 using the droplet discharge device 10. Here, the uppermost or surrounding insulator 42 of the droplet depositing body 34 in FIGS. 9 and 10 may be deposited by the droplet ejection apparatus 10, but deposited by physical deposition means such as sputtering. Also good.

11A and 11B, the metal ultrafine particle dispersion liquid 24 is discharged from the nozzle 12 of the droplet discharge device 10 into a through hole 46 formed on the substrate 44 and having a diameter of 30 μm or less and a depth of 100 μm. Thus, a method of embedding a conductive material will be described. Since the nozzle diameter of the droplet discharge device 10 is 5 μm or less, the tip of the nozzle 12 can be put into the through hole 46.
The tip of the nozzle 12 of the droplet discharge device is inserted into the through hole 46 perpendicularly to the bottom surface of the through hole 46, and the metal ultrafine particle dispersion liquid 24 is discharged from the nozzle 12 and deposited on the bottom surface (FIG. 11A). )). At this time, prior to discharging the ultrafine metal particle dispersion 24, the lyophilic agent is discharged from the nozzle 12 of the droplet discharge device 10 into the through hole 46, and the lyophilic agent is applied to the bottom surface of the through hole 46. Also good. Thereby, evaporation of the solvent contained in the ultrafine metal particle dispersion liquid 24 can be further promoted during discharge, and the influence of deposition shrinkage can be reduced, so that disconnection can be prevented.

  Thereafter, the metal ultrafine particle dispersion liquid 24 is discharged from the nozzle 12 to deposit the metal ultrafine particles 50 in the entire through hole 46 (FIG. 11B). In this case, deposition can be efficiently performed by using a filling nozzle 12 having a large diameter. Note that the shape of the through hole 46 is not limited to a perfect circle, and may be various shapes. In addition, by providing fine notches and protrusions in the through hole 46, conduction utilizing a capillary phenomenon is possible.

At the time of this deposition, droplets are continuously ejected from the tip of the nozzle 12 toward substantially the center of the through-hole 46 to form a droplet deposit column 52 (FIG. 12A). At this time, as shown in FIG. 12 (b), it is preferable that the tip of the droplet depositing column 52 protrudes from the surface of the substrate 44. By providing the protruding tip, droplets are ejected while aiming at the tip, so that the support 52 is prevented from being disconnected.

11A, the tip of the nozzle 12 of the droplet discharge device 10 is inserted into the through hole 46 perpendicularly to the bottom surface of the through hole 46, and the metal ultrafine particle dispersion 50 is discharged from the nozzle 12. Then, after depositing ultrafine metal particles on the bottom surface of the through hole 46, the tip of the nozzle 12 of the discharge device 10 is placed in a predetermined position with respect to the bottom surface of the through hole 46 in the through hole 46, as shown in FIG. It is inserted at an angle, and droplets of the metal ultrafine particle dispersion 24 are continuously ejected toward the wall surface to deposit the metal ultrafine particles on the side wall of the through hole to obtain a sidewall deposit 50 (FIG. 13 ( b)).
Also in this case, before discharging the ultrafine metal particle dispersion liquid 24, a lyophilic agent is applied from the nozzle 12 to the bottom surface and the side surface of the through hole 46, whereby the side wall and bottom surface of the through hole 46 and the ultrafine metal particle dispersion liquid 24 are applied. Can be more closely attached to each other, so that disconnection can be prevented.

Thus, the disadvantage of discontinuity of droplets on the side wall is eliminated. At this time, the droplets 24 are preferably discharged so as to continuously extend from the inner surface of the side wall in the through hole 46 onto the surface of the substrate 44. Therefore, contact bumps can be easily formed on the surface of the substrate 44.
Thereafter, the tip of the nozzle 12 is rotated in the through hole 46, and the droplets of the metal ultrafine particle dispersion 24 are ejected over the entire wall surface, thereby attaching the metal ultrafine particles 50 (FIG. 13C). Using the nozzle 12 of the same discharge device 10 or the nozzle 12 having a large diameter, the metal ultrafine particle dispersion 24 is dropped to deposit the metal ultrafine particles 50 in the through holes 46 (FIG. 13D). ).

Further, after the droplet 24 deposited in the through hole 46 is solidified, the bottom surface of the substrate 44 is polished and cut 52 to expose the surface of the conductive material of the ultrafine metal particles 50 deposited in the through hole 46 penetrating (see FIG. FIG. 13 (e)). The conductive material 50 deposited in the through hole 46 is used to connect the wiring of the upper and lower substrates 44 when the substrate 44 is deposited.

FIG. 14A shows a state in which the ultrafine metal particles 50 are deposited in the through hole 46 at a predetermined height. FIG. 14B shows a state in which the laser 56 is irradiated toward the ultrafine metal particles 50 deposited in the through hole 46. The metal scattered by the laser ablation is deposited on the wall surface of the through hole 46 to ensure conductivity.

In addition, the height of the support | pillar of the droplet deposited in the through hole 46 can be changed by changing the discharge time from the nozzle 12, or the residence time and the residence frequency in the through hole 46 of the nozzle 12. Further, the height of the support column of droplets deposited in the plurality of through holes 46 by arranging the plurality of nozzles 12 is determined by the discharge time from each nozzle 12 or the stay in each through hole 46 of each nozzle 12. It can be changed by changing the time and number of stays.

Further, in order to ensure the conductivity in the vertical direction, which becomes a problem when the conductive material of the through hole 46 is filled, it is preferable to mix a filler such as fine glass fiber in the metal ultrafine particle dispersion ink. However, in that case, since the filler is mixed randomly in the ink, there is a drawback that the nozzle is easily clogged. In the nozzle 12 of the ejection device 10 of the present invention, since a voltage is applied between the ink in the nozzle 12 and the substrate, the filler is polarized and oriented in the electric field direction, thereby eliminating the cause of clogging.

FIG. 15A and FIG. 15B show a method for forming an interlayer wiring. A second substrate 62 is provided on the first glass substrate 60, and patterned holes 64 are formed in the substrate 62. The metal ultrafine particle dispersion liquid 66 is discharged into the hole 64 using the discharge device 10. The discharged metal ultrafine particle dispersion 66 forms a pointed shape at the tip of the deposited liquid (FIG. 15A). Thereafter, the metal ultrafine particle dispersion liquid 66 is filled into the holes 64 to form a metal fine particle deposit 68 (FIG. 15B).

FIG. 16A to FIG. 16E show another method for forming an interlayer wiring. A metal ultrafine particle dispersion is discharged onto the glass substrate 60 using the discharge device 10 to form a metal ultrafine particle deposit 70 having a fine pattern of the metal ultrafine particles (FIG. 16A). Next, a resin 72 is coated on the surface of the substrate 60, and a curing process using UV or heat is performed (FIG. 16B). Subsequently, a liquid repellent 74 is coated on the surface of the resin 72 (FIG. 16C), and the YAG laser 76 is irradiated onto the finely patterned metal ultrafine particle deposit 70.
The ultrafine metal particle deposit 70 absorbs the YAG laser beam 76. The liquid repellent 74 on the metal ultrafine particles is evaporated by the ablation action by the YAG laser 76, and the substrate surface is exposed (FIG. 16D). At this time, the ultrafine metal particle deposit 70 does not necessarily need to absorb the laser beam 76. Thereafter, a metal ultrafine particle dispersion is applied to the surface to form bumps 78 (FIG. 16E).

FIG. 17A and FIG. 17B show a method for forming a bump connection structure, that is, a method for connecting the IC chip 80 to the substrate 60. In FIG. 17A, a metal ultrafine particle dispersion is discharged to the substrate 60 side using the discharge device 10 to form a patterned bump 78. The tip of the bump 78 discharged and deposited from the nozzle 12 of the discharge device 10 is formed in a sharp shape. Pads 81 are formed on the IC chip 80 side. The pads 81 on the IC chip 80 side and the baked bumps 78 on the substrate 60 side are bonded by ultrasonic waves.
The bumps 78 formed using the discharge device 10 may be formed on the IC chip 80 side, and the wiring pattern pads 81 may be formed on the substrate 60 side.

In FIG. 17B, the metal ultrafine particle dispersion is discharged to the substrate 60 side using the discharge device 10 to form a patterned bump 78. The tip of the bump 78 discharged and deposited from the nozzle 12 of the discharge device 10 is formed in a sharp shape. A patterned conductive paste 82 is applied to the IC chip 80 side. The patterned conductive paste 82 on the IC chip 80 side and the baked bumps 78 on the substrate 60 side are joined by thermocompression bonding. The bumps 78 may be formed on the IC chip 80 side using a discharge device, and the conductive paste 82 may be formed on the substrate 60 side in a predetermined pattern.

FIG. 18A to FIG. 18E show a bump forming method. First, the metal ultrafine particle dispersion is discharged onto the glass substrate 60 using the discharge device 10 to form a fine pattern 90 of the metal ultrafine particle dispersion (FIG. 18A). Next, a liquid repellent 92 is applied to this surface (FIG. 18B). After the liquid repellent 92 is applied to the surface, the YAG laser 94 is irradiated to the metal ultrafine particle coating layer that has been subjected to fine patterning (FIG. 18C).
Metal ultrafine particle deposition absorbs YAG laser light 94. At this time, the liquid repellent agent 92 on the metal ultrafine particle pattern 90 is evaporated by the ablation action of the YAG laser 94, the substrate surface is exposed, and patterned fine holes 96 are formed (FIG. 18C). . Thereafter, a metal ultrafine particle dispersion is deposited in the hole 96 to form a bump 98 (FIG. 18E).

FIG. 19 is a diagram showing how much the droplet spreads on the substrate over time after the droplet has landed on the substrate using the droplet discharge device 10 of FIG. The ultrafine metal particle dispersion used is gold nanopaste NPG-J from Harima Chemicals. Gold nanopaste has a viscosity of 11.5 cps, and the substrate is lyophilic treated with an ozone cleaner.

In FIG. 19, the mark ● indicates the transition of the enlargement of the metal ultrafine particle droplet diameter after landing when the nozzle according to the present invention is used. That is, the diameter R1 of the droplet on the substrate surface at the time of landing is about 1 μm, and the diameter R2 of the droplet after 1 second is about 1.8 μm. That is, the ratio between R1 and the solidified droplet R2 1 second after landing is 1: 1.8. In addition, the solidification rate of the droplet after 1 second has elapsed after landing is about 90%.
On the other hand, the ▲ marks indicate the transition of the droplet diameter of the ultrafine metal particles after landing when a conventional nozzle having a nozzle diameter of 10 μm is used. That is, the diameter R3 of the droplet on the substrate surface at the time of landing is about 20 μm, and the diameter R4 of the droplet after one second has been about 100 μm. That is, the ratio between R3 and the solidified droplet R4 1 second after landing is 1: 5.
From this result, it is understood that when the nozzle according to the present invention is used, the enlargement of the droplet diameter of the ultrafine metal particles after landing is extremely small as compared with the use of the conventional nozzle. Therefore, it is possible to draw a finer line with a predetermined line width.

FIG. 20 is a plan view showing a droplet assembly 100 in which droplets are continuously landed on the substrate surface so as to overlap each other. In the figure, droplets 102 land on a substrate so that adjacent droplets overlap each other to form a droplet assembly 100, for example, a wiring. Here, the overlapping degree of adjacent droplets on the substrate surface after landing is about 40% to about 80%, preferably about 50% to about 70%.
In order to form a band such as a wiring of about 1.8 μm, a droplet 102 having a diameter of about 1 μm at the time of landing and a diameter of a droplet solidified about 1 μm after landing is about 1.8 μm continuously adjacent to each other. The liquid droplets to be ejected are ejected from the nozzles so as to overlap each other.

Thus, the method for forming the droplet assembly 100 controls the diameter when the droplet 102 lands on the substrate surface, the diameter of the droplet upon landing on the substrate surface; R, and the droplet solidified after landing. A step of controlling the ratio of the diameter on the substrate surface; R1 to 1: 2 or less, and a step of discharging the droplets so as to continuously overlap each other.

On the other hand, in order to form a belt-like body 103 such as a wiring having a width of about 10 μm by discharging a droplet from the nozzle 12 of the droplet discharge device 10 in FIG. 1 to the substrate, FIG. 21A and FIG. As shown in FIG. 21 (b), the nozzle 102 has a diameter of about 1 μm at the time of landing and a droplet 102 having a diameter of about 1.8 μm solidified after one second from the landing so that the adjacent ones continuously overlap each other. First, both sides of the belt-like body 103 to be formed are formed by discharging from the nozzle 12 (FIG. 21A).
Then, the center part 104 of the strip | belt-shaped object 103 is formed (FIG.21 (b)). When forming the central portion 104 of the strip 103, the voltage and / or frequency applied to the nozzle 12 is made higher than the discharge amount to both sides, and more droplets are discharged.

Thus, the belt-like body 103 made of the liquid droplet aggregate formed by continuously landing the liquid droplets on the substrate surface so as to overlap each other is the belt-like shape on both sides of the liquid drop 102 having a relatively small diameter. It consists of a body 102 and a collection of droplets 104 having a relatively large diameter.

Here, the strip 102 can also act as a droplet assembly for preventing pattern expansion. In this case, in the case of a strip having a width of 10 μm, the strip for preventing pattern expansion 102 is formed at a position of about 1.5 μm to about 2.0 μm in the center direction from the edge of the strip having a desired width.

When forming the band-like body 103 such as a wiring of about 2 μm, in order to form the width of the band-like body 103 to a predetermined dimension, it is necessary to suppress the spread of the pattern shape due to the droplets as much as possible. In FIG. 22, in order to form the strip 103 having a pattern shape with a predetermined width extending in the longitudinal direction using the droplet discharge device 10 of FIG. 1, it should be formed before the strip is formed. A droplet aggregate 106 for preventing pattern expansion is formed by continuously or non-continuously dropping droplets at positions separated from about 0.1 μm to 0.5 μm outside from at least one edge side of the strip 103.

FIG. 23 shows another method for forming a band-like body. In the figure, a pattern expansion preventing droplet assembly 106 for preventing the expansion of the pattern shape is formed continuously or discontinuously at the center of the strip 103 to be formed. Thereafter, the metal ultrafine particle dispersion is ejected from the droplet ejection device 10 toward the pattern shape disorder preventing droplet aggregate 106 to form a fine wiring pattern having a desired width.

FIG. 24 shows still another method for forming the strip 103. The figure shows a state in which the strip 103 is curved. In the same figure, the pattern expansion preventing droplet assembly 106 for preventing the pattern expansion of the strip 103 is approximately at the inner side along the curved shape of the strip 103 on at least one edge side of the strip 103. It is formed continuously or discontinuously within 1.5 μm.

FIG. 25 shows another method of forming a pattern shape disorder preventing droplet aggregate 106 for preventing the pattern of the band 103 from expanding. In the same figure, the pattern expansion preventing droplet assembly 106 is formed by landing droplets continuously or discontinuously in the longitudinal direction along at least the outer sides of both sides of a strip 103 having a desired width. Here, the pattern expansion preventing droplet aggregate 106 is formed by discharging droplets made of an insulating material from the droplet discharge device 10 of FIG.

The electric connector forming method of the present invention and the electric connector obtained thereby include three-dimensional wiring, interlayer connection wiring, blind via, through-hole wiring, single-sided stud bump, double-sided stud bump, crimped wiring, ultrasonic bonding wiring, etc. It can be applied to a wide variety of electrical connectors.

It is explanatory drawing of one embodiment of the droplet discharge apparatus used for this invention. It is explanatory drawing of another embodiment of the droplet discharge apparatus used for this invention. FIG. 4 is a schematic view showing one embodiment of (a) an initial stage in the case of providing an electric field concentration electrode, (b) an intermediate stage, (c) a late stage, and (d) a late stage in the discharge process of the present invention. It is the schematic which shows one embodiment of the droplet discharge apparatus used for this invention. It is another schematic diagram showing one embodiment of a droplet discharge device used in the present invention. It is another schematic diagram which shows one embodiment of the droplet discharge apparatus used for this invention. It is the schematic which shows the droplet deposit body formed by depositing the droplet splashed toward the board | substrate from the nozzle of the droplet discharge apparatus (the 1). It is the schematic which shows the formation method of the droplet deposit body of Fig.7 (a). It is the schematic which shows the droplet deposit body formed by depositing the droplet disperse | distributed toward the board | substrate from the nozzle of the droplet discharge apparatus (the 2). It is the schematic which shows the droplet deposition body formed by depositing the droplet disperse | distributed toward the board | substrate from the nozzle of the droplet discharge apparatus (the 3). It is the schematic which shows the droplet deposition body formed by depositing the droplet disperse | distributed toward the board | substrate from the nozzle of the droplet discharge apparatus (the 4). It is the schematic which shows the structure for preventing a breadth spreading and making a droplet deposited body into a predetermined diameter when patterning a catalyst on a board | substrate. It is the schematic which shows the state which provided the insulator in the uppermost part of the droplet depositing body using the droplet discharge apparatus. It is the schematic which shows the state which provided the insulator around the droplet deposit body using the droplet discharge apparatus. (A) And (b) is the schematic which shows the method of embedding a conductive material by discharging a metal ultrafine particle dispersion liquid from the nozzle of a droplet discharge device in the through hole formed in the board | substrate. (A) And (b) is the schematic which shows the method of forming an electrical connection body in a through hole. (A)-(e) is another schematic diagram which shows the method of forming an electrical connection body in a through hole. (A) And (b) is another schematic diagram which shows the method of irradiating a laser to a metal ultrafine particle dispersion and forming an electrical connection body. (A) And (b) is the schematic which shows the formation method of interlayer wiring. (A)-(e) is the schematic which shows the formation method of another interlayer wiring. (A) And (b) is the schematic which shows the formation method of bump connection structure. (A)-(e) is the schematic which shows the formation method of bump. It is a figure showing how much a droplet spreads on a substrate by progress of time after a droplet landed on a substrate. It is the schematic which shows the droplet aggregate | assembly formed by making a droplet land continuously on a substrate surface so that it may mutually overlap. (A) And (b) is the schematic which shows the method for forming wiring accurately. It is the schematic which shows the other method for forming wiring accurately. It is the schematic which shows the other method for forming wiring accurately. It is the schematic which shows the method for forming a strip | belt-shaped object accurately. It is the schematic which shows the further method for forming a strip | belt-shaped object accurately.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Droplet discharge device 12, 32 Nozzle 14, 20 Electrode 16 Control device 18 Cartridge 22, 44 Substrate 24, 66 Metal ultrafine particle dispersion 30 Needle electrode 34 Droplet deposit 36 Catalyst 50, 68, 70 Metal ultrafine particle Deposition 42 Insulator 46 Through-hole 60 First substrate 62 Second substrate 64 Hole 66 Metal ultrafine particle dispersion 72 Resin coating 74, 92 Liquid solution 78 Bump 80 IC chip 81 Pad 82 Conductive paste 90 Dispersion fine pattern 94 YAG laser 96 Micropore 98 Bump 100 Droplet assembly 103 Strip 106 Droplet assembly for preventing turbulence

Claims (7)

An electrical connection body comprising a droplet deposit formed on a substrate by controlling a voltage applied to the nozzle and discharging a droplet from the nozzle toward the substrate,
The droplet deposit is
A preceding landing droplet layer landed on the substrate;
A solidified growth origin droplet layer on the preceding landing droplet layer;
A solidified droplet deposition layer on the growth origin droplet layer,
The growth origin droplet layer is less wet spread than the preceding landing droplet layer,
The growth origin droplet layer has a tip that is a growth point where electric charges gather and is formed by starting growth by increasing the density of the electric charge and changing the distribution of electric lines of force. body. The electrical connection body according to claim 1, wherein a ratio of a diameter of the growth origin droplet layer to a diameter of the droplet deposition layer is 2: 1 to 1: 1. The electrical connection body according to claim 1, wherein the droplet deposition layer includes a top portion, and the diameter of the top portion is larger than the diameter of the droplet deposition layer. The electrical connection body according to claim 1, wherein the droplet deposition body includes an insulator around a side portion. An electrical connection body comprising a droplet deposit formed on a substrate by controlling a voltage applied to the nozzle and discharging a droplet from the nozzle toward the substrate,
The droplet deposit is
A droplet assembly for preventing pattern expansion formed by droplets landing continuously or discontinuously on the substrate;
An electrical connector comprising: a fine wiring pattern formed by ejecting a metal fine particle dispersion and forming metal fine particles overlapping each other on the pattern expansion preventing droplet aggregate. 6. The electrical connector according to claim 5, wherein the pattern expansion preventing droplet aggregate is formed on at least one edge side of a fine wiring pattern to be formed. A cartridge for storing droplets constituting the electrical connection body according to any one of claims 1 to 6 and being detachably provided in a droplet discharge device.

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