JP2012213886A - Screen printing method, and apparatus for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a stable printing with a high precision regardless of the size of the opening area at the opening part of a printing mask in a printer which transfers a paste to a predetermined location of a to-be-printed object being fixed on a table from the printing mask including the opening at a predetermined location by using a squeegee.SOLUTION: An arc-like recessed shape is formed at one of the corners of the distal end of the squeegee. The surface of the distal end part of the squeegee including the arc-like recessed shape part is coated with a film having liquid repellency. When the paste is filled and transferred to the printing mask including a desired pattern opening part, the rolling of the paste at the arc-like recessed shape part which has been coated with the film having liquid repellency is accelerated, and the filling property of the paste to the pattern opening part of the printing mask is accelerated.

Description

  The present invention relates to a screen printing method and apparatus for printing a viscous printing material on a printing material using a squeegee through a printing mask having a predetermined opening pattern on the printing material.

  Screen printing is a stencil printing method in which a paste (printing agent) such as ink is squeezed (pushing out the paste (printing agent) with a squeegee) and passed through a screen having an opening pattern to transfer a desired pattern to the printing material. It is used for various purposes such as circuit wiring formation of an IC substrate and FDP (Flat Display Panel) pattern formation (electrode formation and phosphor filling).

  Screen printing is also used, for example, for solder paste printing performed prior to mounting electronic components on a printed circuit board. The solder paste is a cream obtained by mixing solder alloy powder and high-viscosity liquid flux, and is transferred onto a substrate through a printing mask having a predetermined opening pattern. For this screen printing, metal printing masks and metal squeegees that are excellent in terms of mechanical strength and the like are widely used.

  Hereinafter, the current solder printing will be described with a printing mask referred to as a metal screen, a squeegee as a metal squeegee, and a solder paste as a paste.

  A metal squeegee is applied with pressure (printing pressure) to the screen surface on which paste is supplied on the surface with its tip inclined at a predetermined attack angle (for example, 70 degrees) with respect to the screen surface of the metal screen. By sliding in the printing direction, the paste pattern is transferred onto the substrate via the opening pattern formed on the metal screen.

  Since the printed surface of the printed wiring board introduced into the paste printing process has irregularities of about 20 μm to 80 μm due to the solder resist or electrode wiring applied in the previous process, the thickness is about 100 μm made of stainless steel. The metal screen is locally pushed up by the unevenness of the printed wiring board during printing, and a gap is formed between the metal mask and the printed wiring board. Therefore, when the metal squeegee passes through the convex portion of the metal screen raised by the convex portion of the printed surface of the printed wiring board, a gap is generated between them, which causes a printing defect.

  In order to prevent this, the gap is suppressed to be small by performing printing while applying a large printing pressure to the metal squeegee. For this reason, conventional metal squeegees are made of special steel (super hard alloy) with excellent wear resistance to enhance its durability.

  Further, as a solution to these problems, Japanese Patent Laid-Open No. 10-100374 (Patent Document 1) discloses that a tapered surface is formed by etching at the tip opposite to the printing direction of the metal squeegee to facilitate elastic deformation. It is described that stable printing is possible even with a small printing pressure, and damage to the screen surface of the metal screen is reduced.

  A printing method using a resin squeegee instead of a metal squeegee is employed as a solution to printing defects due to the level difference of the substrate and a damage reduction measure for the metal screen.

  Hereinafter, screen printing using a resin squeegee will be described by referring to a printing mask as a mesh screen and a squeegee as a urethane squeegee.

Conventional urethane squeegees include flat squeegees, square squeegees, and sword squeegees.
As a method for stabilizing the attack angle which is a problem with a flat squeegee, as described in Japanese Utility Model Laid-Open No. 3-055230 (Patent Document 2), it is made of urethane rubber using a glass epoxy resin as a support. A squeegee has been proposed. The squeegee includes a support body having a base end portion attached to the holder, and a squeegee portion that is integrally fixed so as to cover the front end portion at a front end portion facing the base end portion of the support body. The material of the support is made of glass epoxy resin having elastic restoring force, and the shape is flat.

  The material of the squeegee portion is made of urethane rubber, and a groove portion is provided in the width direction at the other end portion of the squeegee facing the squeegee tip portion to be squeezed, so that the tip portion of the support body is sandwiched. In this way, they are fixed together.

  According to this conventional example, the screen surface can be squeezed by using the squeegee having such a configuration and fixing the squeegee to the holder on the base end side. At this time, when squeezing for a long time, even if the tip of the squeegee changes (swells) due to the solvent contained in the ink (paste), the support material is made of glass epoxy resin. Therefore, the waist force of the entire squeegee does not change and can be squeezed stably.

  Japanese Utility Model Laid-Open No. 1-91536 (Patent Document 3) describes that a metal core is incorporated in the squeegee to avoid bending the squeegee.

  As a metal mask used for screen printing, a metal plate is arranged in a space in a printing mask plate frame, and the metal plate is a tension mesh provided over the entire circumference between the metal plate and the printing mask plate frame. There is a combination mesh type that is supported by the printing mask plate frame in a tensioned state.

  This printing mask is used for screen printing by making a printing mask having a predetermined pattern opening in an effective printing area corresponding to a moving area of a squeegee moved on the metal plate. is there.

  By making the upper surface of the printed material face the lower surface of the metal mask, sliding the squeegee on the upper surface of the metal mask, filling the opening provided in the metal mask with the paste, and then separating the printed material from the metal mask. Used to transfer printing material onto a substrate.

  In the metal plate, an opening having a predetermined pattern is formed in the effective printing area by laser processing, plating, etching, or the like.

  For example, in the etching method, a photoresist is applied on both sides of the metal plate, and the resist film is exposed using an exposure mask having a predetermined pattern and then etched.

  Screen printing methods include, for example, electronic devices, printing of electrode wiring on a printed wiring board, printing of a frame-shaped sealing material on a liquid crystal display substrate, a dielectric layer on a plasma display substrate, pixel spacing walls and electrodes. It is used for various printing such as wiring and fluorescent material printing. The size of the mesh mask, that is, the area of the screen mesh, the size of the printing mask plate frame, the width of the tension mesh, etc. is designed according to the application. Has been.

Japanese Patent Laid-Open No. 10-100430 Japanese Utility Model Publication No. 3-055230 Japanese Utility Model Publication No. 1-91536

  By the way, with the recent miniaturization of surface mount components, the area of the pad of the printed wiring board has been reduced, and accordingly, the area of the opening of the print mask has also been reduced.

  In this way, the squeegee described in Patent Document 1, that is, the metal squeegee in which the tapered surface is formed by etching with respect to the opening having a small opening area, has insufficient force to push the paste into the opening of the printing mask. Adhesiveness between the pad of the printed wiring board and the paste in the opening becomes insufficient, and as a result, the paste remains in the opening of the printing mask, and the paste cannot be printed (transferred) on the pad of the printed wiring board, or In some cases, the amount of printed paste is insufficient.

  Generally, a metal squeegee has a weaker force to push a paste into an opening of a printing mask than a rubber squeegee made of urethane, and is considered to have caused the above-described problems.

  In general, the tip of the metal squeegee is required to have a high degree of flatness and flatness. However, the conventional metal squeegee described above includes the material (raw material) and the tip of the squeegee. However, there is a problem that the cost is very high. Furthermore, the tip of the squeegee is subjected to a coating treatment such as polytetrafluoroethylene widely known as Teflon (registered trademark) in order to reduce frictional resistance and perform stable printing. In addition, it is a cause of the high cost of metal squeegees.

  Further, the screen surface of the metal screen that is subjected to the sliding contact action with a high printing pressure by the metal squeegee made of cemented carbide has a large damage, particularly in the protrusion raised from the printed wiring board side as described above. . That is, there is a problem that damage on the metal screen side is large in order to perform stable printing using a conventional metal squeegee.

  In general, the squeegee includes a squeegee portion and a holder attaching portion attached to the squeegee holder. The squeegee holder fixes the squeegee by attaching the holder attachment portion of the squeegee. The squeegee holder has a predetermined angle with respect to the printing surface. The attachment angle of the squeegee holder to the printer base can be adjusted to a desired angle.

  The squeegee unit is controlled to move along the surface of the screen mesh at a speed suitable for screen printing while applying a printing pressure suitable for screen printing to the screen mesh. Printing pressure is applied to the point where the squeegee portion and the screen mesh abut. At the point where the squeegee portion and the screen mesh abut, the screen mesh is pushed down toward the surface of the printing material, and an image of the opening pattern formed on the screen is printed on the surface of the printing material. For this reason, in order to perform high-quality printing, it is important that the screen mesh is stretched evenly in a balanced manner on the screen frame and tensioned. The squeegee and the screen are preferably in line contact. Further, it is desirable that the contact line is a straight line.

  The squeegee is in contact with the printing surface at a certain angle, and printing pressure is applied to the printing surface. For this reason, there is a problem in that the angle between the squeegee and the printing surface (referred to as the attack angle) cannot be maintained at a constant angle because the tip of the squeegee is bent. That is, the conventional flat squeegee has a problem that the attack angle changes during printing. However, when the substrate (for example, the above-described printed wiring board) has irregularities, there is an advantage that the irregularities follow the irregularities due to the flat squeegee.

  In a conventional flat squeegee, the entire squeegee part has uniform elasticity, and there is no low back force. Therefore, the shape of the squeegee is stabilized by using metal for the holder mounting part attached to the printing device. Was kept. Further, since the entire squeegee portion has uniform elasticity, there is a drawback that it is difficult to keep the attack angle constant.

  In addition, the conventional square squeegee and sword squeegee cannot be mechanically polished, and there is a problem that it is difficult to obtain linearity between the printing surface and the contact surface of the squeegee.

  In addition, the squeegee described in Patent Document 2, that is, the squeegee made of urethane rubber with a glass epoxy resin as a support, and the squeegee incorporating the metal core material described in Patent Document 3, Although it is possible to suppress the overall bending that is a problem, the paste rises on the side of the squeegee during printing, so the force to push the paste into the opening of the print mask is insufficient, and the printed wiring board pad And the paste in the opening becomes insufficient, and as a result, the paste remains in the opening of the print mask, and the paste cannot be printed (transferred) on the pad of the printed wiring board, or the printed paste There may be a problem that the amount is insufficient.

  Generally, screen printing using a mesh mask differs from screen printing using a metal mask, and requires a paste coating with a scraper on the printing mask (screen surface side) before printing with a squeegee. That is, the paste can be coated and retained using the mesh present in the opening of the print mask (mesh mask), and the amount of paste discharged can be increased during printing with a squeegee. Conversely, the metal mask cannot coat the print mask with a paste because there is no member to be held in the pattern opening.

  When a metal mask is used, printing is completed in one direction, so that the time required for printing can be shortened compared to a mesh mask that requires a paste coating.

  The mesh mask is provided with a clearance (gap) between the printing mask and the printing material, and can release the plate almost simultaneously with printing.

  On the other hand, since the metal mask does not provide a clearance (gap) between the printing mask and the substrate to be printed, a plate separation step (step of separating the printing mask and the substrate) after printing is required.

  Therefore, even if a mesh mask is used, it is important to complete printing by a one-way operation as in the case of a metal mask. To that end, a structure and surface capable of simultaneously satisfying the coating function of the paste for improving the filling property to the opening pattern of the printing mask and the printing function for transferring from the printing mask to the printing material at the tip of the squeegee Having a state is an issue.

  In general, since paste has improved fluidity when shear (shearing force) is applied, the viscosity is lowered and the fluidity is improved by rolling. At the same time as printing using a squeegee, improving the releasability of the paste from the squeegee to improve the rolling property of the paste and improving the printability (fillability / transferability) is also an issue.

  Furthermore, when the paste is printed using a squeegee, the paste rises along the side of the squeegee opposite to the print mask, so that the paste in the print mask is insufficiently filled.

  The problem is to find the structure and surface state of the tip of the squeegee that has features that can solve such problems.

  In addition, since the paste is filled into the opening pattern formed in the printing mask by the tip of the squeegee, the shape of the tip of the squeegee affects the paste filling property to the printing mask, so that the filling ability is improved. The structure and surface state of the squeegee tip that can be improved over the squeegee are problems. In particular, since the direction of the force applied to the paste changes depending on the attack angle between the tip of the squeegee and the printing surface of the printing material, it is a problem to fill the opening pattern formed in the printing mask from the substantially vertical direction.

  On the other hand, since the load by printing pressure is added to a squeegee, a front-end | tip part deform | transforms. As described above, since a flat squeegee made of urethane is generally bent, the attack angle at the tip of the squeegee becomes very small, and the attack angle varies depending on the level difference of the substrate. When the attack angle varies, the filling property to the opening portion of the printing mask changes, so that it is a problem to reduce the variation in filling property.

  Depending on the object to be printed, a metal mask, a mesh mask, or the like may be used as a print mask. The problem is to make the squeegee compatible with any printing mask. Moreover, as a printing mask, it is a subject to stably transfer a desired amount of paste onto a substrate.

  Furthermore, the paste used varies depending on the printing object. Paste is a high-viscosity material that is a mixture of solids and liquids. Depending on the purpose, the solids are coated with solder composition particles, silver particles, flaky silver particles, nickel-based particles, and metal. It is an object to provide a squeegee that can use a paste mainly composed of at least one of the resin particles, ceramic particles, and glass particles.

  The present invention has been made in view of the above-described problems, and provides a screen printing method and apparatus capable of printing a paste accurately and stably regardless of the size of the opening area of the opening of the printing mask.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  Attaching the squeegee to the printing machine includes a case where the squeegee is inclined in the direction opposite to the printing direction and a case where the squeegee is inclined in the printing direction. When the squeegee is inclined in the direction opposite to the printing direction, the direction of the squeegee surface with which the paste contacts and the squeegee mounting angle are substantially perpendicular. On the other hand, when the squeegee is inclined in the printing direction, the direction of the squeegee surface where the paste contacts and the squeegee mounting angle are substantially the same.

  Regardless of the method of attaching the squeegee, in a printing apparatus that uses a squeegee to transfer a paste from a printing mask having an opening at a predetermined position to a predetermined position of a substrate fixed on a table, The corner has an arcuate concave shape, and is characterized in that the attack angle between the squeegee and the printing surface of the substrate is smaller than the squeegee mounting angle.

  As a result, the paste is confined in the arc-shaped concave portion at the tip of the squeegee, and the paste is squeezed in the process of squeezing (the squeegee slides in the printing direction while applying pressure (printing pressure) to the screen surface of the printing mask). It is possible to roll along the arcuate concave shape at the tip.

  Furthermore, at least the surface of the squeegee tip that contacts the paste including the arc-shaped concave portion repels the paste (liquid is ink-like oil, and liquid repellency is ink-like oil. It has a repelling property and exhibits the same property as hydrophilicity), so that the frictional force between the paste and the squeegee surface is reduced and the rolling property is improved. When the rolling property is improved, the shear rate is increased, the viscosity of the paste is lowered, and the paste is more easily flowed.

  Here, as a method for quantifying the liquid repellency of repelling the paste, the droplet angle (contact angle) at the point where the droplet is dropped on the substrate surface and in contact with the substrate on the outer periphery of the droplet is used. . If the contact angle is small, it indicates that the liquid droplets are wet and spread on the substrate surface. Conversely, if the contact angle is large, the liquid droplets are raised on the surface of the substrate and the droplets are repelling. Show.

  The liquid repellency of the squeegee surface needs to be evaluated with a solvent contained in the paste. When the solvent contained in the paste is dropped on the surface of the squeegee and the contact angle is less than 45 degrees, the paste rises along the surface of the squeegee and the rolling speed decreases. When the contact angle is 45 degrees or more, the liquid repellency of the squeegee surface is improved, the paste is difficult to spread on the squeegee surface, and the rolling property of the paste is improved. The larger the contact angle, the better.

As the film having liquid repellency, a film that dissolves in the solvent contained in the paste is not preferable. Examples of the material having resistance to the solvent contained in the paste and having liquid repellency include SiO ₂ , fluororesin, hydrocarbon, and fluorine-containing hydrocarbon.

  If the mounting angle of the squeegee is reduced in order to reduce the attack angle, the housing of the squeegee head that applies the printing pressure and the location where the tip of the squeegee contacts the print mask will be displaced relative to each other. It will not be applied effectively to the tip. That is, when a relative displacement occurs in the force point, a rotational moment works. In this case, the higher the printing pressure, the more the squeegee tip has a force in the direction opposite to the printing pressure.

  Therefore, the contact point between the direction in which the printing pressure is applied to the squeegee head and the printing mask at the tip of the squeegee is preferably in the same direction.

  The gap between the arcuate concave shape at the tip of the squeegee tip and the other side of the arcuate concave shape at the tip of the squeegee and the print mask is at least 10 times the average particle size of the paste used. There is a feature. The other of the arcuate concave shapes at the tip of the squeegee means a tip that is a concave shape processed into an arc shape at the tip of the squeegee and is not in contact with the printing mask.

  The gap between the tip and the printing mask is related to the size of solid particles contained in the paste used. When the squeegee comes into contact with the print mask, the squeegee may not only fill the opening of the print mask with the paste, but also discharge the print mask toward the substrate. Thereafter, since the tip of the squeegee that originally contributes to printing reaches the opening of the printing mask, a situation in which printing is performed twice is created.

  Similarly to the filling of the paste in the opening pattern portion of the printing mask, the opening pattern portion needs to be at least 10 times larger than the particle size of the solid content in the paste. If the opening pattern portion is smaller than that, the fluidity of the paste will be hindered, and the opening pattern portion will be clogged with particles in the paste, making it impossible to permeate the paste well. Therefore, the gap between the squeegee and the printing mask needs to be at least 10 times the average particle size of the paste used.

  On the other hand, the smaller the gap between the squeegee and the print mask, the greater the force applied to the paste and the better the filling ability of the print mask into the opening pattern portion.

  By processing the tip of the squeegee in contact with the print mask into a special shape in this way, the paste is coated on the print mask to a predetermined thickness, the paste is rolled, and the paste is opened in the print mask. It is possible to have a function of filling the part.

  Here, the material of the squeegee used is a resin whose main component is urethane, and its hardness is 80 degrees or more. If the hardness is low, even if a support that suppresses deformation of the squeegee is used as a support, the tip of the squeegee is deformed by the printing pressure during printing, and the attack angle between the squeegee and the printing surface becomes unstable.

  Metal squeegees can be made with extremely high hardness, but the printed surface of the printed wiring board has irregularities formed by solder resist, electrode wiring, etc. applied in the previous process. Flexibility is required at the tip.

  Therefore, in order to provide the squeegee with shape retention and flexibility, a core material is used at the center of the squeegee. The core material should have conductivity, and a material made of stainless steel is particularly good. The core material can be used as an electrode for forming a liquid-repellent film by plasma treatment.

  Moreover, the squeegee mounted in the printing apparatus of the present invention can use a printing mask (metal mask) characterized by having a metal plate having a predetermined opening as a printing mask. A printing mask characterized by having an organic layer on the surface to be printed can be used.

  Furthermore, the squeegee mounted in the printing apparatus of the present invention is a printing mask (mesh) in which a pattern forming area is composed of an emulsion composed of at least a metal mesh and an organic substance, and the emulsion has a predetermined opening. Mask) can be used.

  The print mask using the squeegee mounted in the printing apparatus of the present invention is not limited to the metal mask, mesh mask, etc. described here.

  The present invention relates to a method of printing a pattern by a screen printing method, for example, an electronic device, printing of electrode wiring on a printed wiring board, printing of a frame-shaped sealing material on a liquid crystal display substrate, and dielectric on a substrate for plasma display By printing in various fields such as printing of layers, pixel interval walls, electrode wirings, and fluorescent materials, it is possible to print fine patterns that were impossible with the prior art.

  According to the squeegee of the present invention, the paste can be printed accurately and stably regardless of the size of the opening area of the opening of the printing mask.

FIG. 3 is a cross-sectional view simulating a situation where printing is performed using the squeegee of Example 1. It is a top view of the 1st example explaining connection of a power connection terminal to the squeegee of Example 1. FIG. FIG. 3 is a block diagram illustrating a schematic configuration of a printing apparatus on which the squeegee according to the first exemplary embodiment is mounted. FIG. 3 is a flowchart showing a flow of processing for performing screen printing in a printing apparatus equipped with the squeegee of Embodiment 1; 1 is a side view of a squeegee mechanism showing a schematic configuration of a squeegee mechanism of Example 1. FIG. It is a figure explaining the movement of the squeegee with respect to the mask when screen printing is performed by the squeegee mechanism of Example 1, and the state of the paste flow at the squeegee tip. FIG. 4 is a diagram illustrating a state of paste flow at the squeegee tip when screen printing is performed by the squeegee mechanism of the first embodiment. 1 is a side view of a squeegee mechanism showing a schematic configuration of a pair of squeegee mechanisms used in Embodiment 1. FIG. It is an enlarged view of the front-end | tip part of the squeegee mechanism used for Example 1. FIG. It is an enlarged view of the concave shape part formed in the front-end | tip part of the squeegee mechanism used for Example 1. FIG. 3 is a schematic diagram of various squeegee tip shapes used in evaluation experiments in Example 1. FIG. FIG. 6 is a schematic diagram of the tip shape of the squeegee in which a surface parallel to the mask is formed at the tip portion of the squeegee in a modification of the first embodiment. FIG. 10 is a side view of a squeegee mechanism showing a schematic configuration of a squeegee mechanism used in Example 4; It is a principal part enlarged view of the squeegee structure explaining a front-end | tip shape. It is the schematic of various squeegee tip shapes used for evaluation experiment in Example 4. It is an enlarged view of the front-end | tip part of the squeegee mechanism used for Example 4. FIG.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof is omitted in principle. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A configuration of the squeegee 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view simulating a situation where printing is performed using the squeegee 1 of the first embodiment. In FIG. 1, for the sake of simplicity, notations such as a holder for fixing the squeegee 1 to the printing apparatus and an opening formed in the printing mask 11 are omitted.

  The squeegee 1 is covered with a urethane resin 101 around a core material 102, and a liquid repellent film 103 is formed on the surface thereof. Further, an arcuate concave portion 8 is formed at the tip of the squeegee 1. When printing, the paste 9 can be printed by operating the squeegee 1 in the printing direction 2 in a state where printing pressure is applied to the squeegee 1 and pressed against the print mask surface 5 of the print mask 11. .

An example of a method for manufacturing the squeegee 1 according to the first embodiment will be described.
First, as a pre-process, a structure that is the basis of the squeegee 1 is created.
Using a mold machined to a predetermined size, a stainless steel square material used as the core material 102 is set, and a solution used as a raw material for the urethane resin 101 is poured into the mold. Heat is applied with an appropriate temperature profile to cure the urethane resin 101. When the temperature dropped, the squeegee 1 was taken out of the mold to produce a structure of the squeegee 1 in which the urethane resin 101 was formed around the core material 102. In this way, the urethane resin 101 having a hardness of 80 degrees or more is formed. As an example, the squeegee tip is processed with a squeegee grinder so that the tip of the squeegee has a predetermined shape (arc-shaped concave portion 8). As a preliminary, polishing of a predetermined shape (arc-shaped concave portion 8) to the tip of the squeegee may be formed on the diagonal of the squeegee 1 in some cases.

As an example of the liquid repellent treatment of the squeegee surface, a method of forming a hydrocarbon film will be described.
The hydrocarbon film is formed by plasma treatment. First, masking is performed on the squeegee 1 produced in the previous step to expose only the portion where the hydrocarbon film is formed.

  FIG. 2 is a plan view of a first example for explaining a method of connecting a power connection terminal to the squeegee 1 incorporating the core material 102 as an example. In FIG. 2, notations such as power connection terminals and masking are omitted for simplification. A power connection terminal (not shown) is attached to a hole 104 for connecting a power connection terminal formed on the core member 102 exposed at both ends of the squeegee 1 in the longitudinal direction, and placed in a film forming apparatus chamber (not shown). High-frequency power is applied to the core material 102 through the power supply connection terminal in a state where the carbon-containing compound gas is introduced as the material gas. As a result, plasma is generated in the chamber of the film forming apparatus, and a diamond-like hydrocarbon film (diamond-like carbon film) is formed on the surface of the urethane resin 101. The hole 104 for connecting the power connection terminal formed in the core member 102 may be provided only on one side, as long as the power can be introduced.

  In this way, diamond-like carbon, which is a liquid-repellent film 103 that repels paste, was formed on the surface of the urethane resin 101 of the squeegee 1.

  The configuration of the printing apparatus 100 equipped with the squeegee 1 according to the first embodiment will be described with reference to FIG. FIG. 3 is a front view of the printing apparatus 100 equipped with the squeegee 1 of the first embodiment. In FIG. 3, for the sake of simplification, the display of the frame, side wall, column, support member, etc. of the apparatus is omitted.

  The printing apparatus 100 includes a printing mask unit 110, a substrate support table unit 23, a pair of squeegee units 120L and 120R, a squeegee driving mechanism unit 130, and a control unit 21.

  The print mask portion 110 is in a tension state with a metal mask 11 provided with a pattern opening formed corresponding to a desired circuit pattern of a substrate (for example, a printed wiring board) 6 and a tension mesh surrounding the metal mask 11. A plate frame 22 having a rectangular shape in a plan view and a support member 111 that supports the plate frame. The substrate support table unit 23 includes a table 231 on which the substrate 6 is placed, a chuck unit 232 that fixes the substrate 6 placed on the table 231, and a vertical drive unit 233 that drives the table 231 up and down. .

  The squeegee unit 120L includes a squeegee 1L, a squeegee holder 3L, a squeegee holder fixing jig 16L, and a squeegee head 15L air cylinder 24L. Similarly, the squeegee unit 120R includes a squeegee 1R, a squeegee holder 3R, a squeegee holder fixing jig 16R, a squeegee head 15R, and an air cylinder 24R. The air cylinders 24L and 24R are fixed to the support member 25, and drive the squeegee portion 120L and the squeegee portion 120R connected to the air cylinders 24L and 24R, respectively, up and down. The support member 25 is supported by bearings 26L and 26R engaged with the drive shaft 27. The drive shaft 27 is constituted by a ball screw, and when it is rotationally driven by the motor 30, the bearing portions 26L and 26R engaged with the drive shaft 27 move in the left-right direction in the drawing, and the squeegee portion 120L and the squeegee portion 120R. Moves along the guide shaft 28 in the horizontal direction in the figure. The drive shaft 27 and the guide shaft 28 are supported by a pair of left and right fixing plates 29L and 29R.

  The control unit 21 controls the operation of each unit of the printing apparatus 100. First, the air cylinder drive unit 31 that drives the pair of air cylinders 24L and 24R is controlled by a control signal from the control unit 21 to drive the pair of air cylinders 24L and 24R, respectively. Further, the control unit 21 controls the driver unit 32 of the motor 30 to rotate the motor 30 in the forward and reverse directions. Further, the chuck drive unit 34 that drives the chuck unit 232 of the substrate support table unit 23 is controlled by the control signal from the control unit 21 to open and close the chuck unit 232 that fixes the substrate 6 placed on the table 231. Let the action take place. Furthermore, the table drive unit 33 that drives the vertical drive unit 233 of the substrate support table unit 23 is controlled by a control signal from the control unit 21 to move the table 231 up and down. Furthermore, the chuck 232 is opened and closed by controlling the drive unit 34 of the chuck 232 of the substrate support table unit 23 according to a control signal from the control unit 21.

The operation of the printing apparatus having the above configuration will be described with reference to the flowchart of FIG.
First, the substrate 6 is conveyed by a conveying means (not shown) and placed on the substrate support table 23 (S201), and the substrate 6 is fixed and held on the substrate support table 23 by the chuck portion 232. . Next, the table driving unit 32 drives the vertical driving unit 233 to raise the table 231 (S202), and the substrate 6 is brought into close contact with the metal mask 11 of the printing mask unit 110. Next, the air cylinder 24L is driven by the air cylinder drive unit 31 to lower the squeegee head 15L (S203), and the squeegee 1L is brought into close contact with the metal mask 11 (S204). At this time, the pair of squeegee portions 120L and 120R are located at the left end portion of FIG.

  Next, in this state, paste is supplied to the vicinity of the squeegee 1L by paste supply means (not shown) (S205). When the paste is supplied, the driver unit 32 is controlled to drive the motor 30, and the drive shaft 27 formed of a ball screw is rotated so that the pair of squeegee units 120L and 120R and the squeegee 1L attached to the tip of the squeegee 1L. A pattern of the metal mask 11 made of paste is printed on the substrate 6 by moving the metal mask 11 from the left side to the right side in FIG. 3 while being pressed against the metal mask 11 (S206). After the squeegee 1L has moved a predetermined distance, the driver unit 32 stops driving the motor 30 and stops the movement of the squeegee 1L.

  Next, the air cylinder drive unit 31 drives the air cylinder 24L to raise the squeegee head 15L (S207), and the squeegee 1L is pulled away from the metal mask 11. Next, the table drive unit 33 controls the vertical drive unit 233 to lower the table 231 (S208), and the substrate 6 held by the chuck unit 232 is peeled off from the metal mask 11. When the table 231 reaches the descending end, the processing of the table 231 by the vertical drive unit 233 is stopped, the chuck drive unit 34 is controlled to open the chuck unit 232 holding the substrate 6 and handling means (not shown) Thus, the substrate 6 is removed from the table 231 (S209). It is determined whether or not the substrate thus taken out is the last substrate to be processed (S210). In the last case, the processing is terminated.

  On the other hand, if there is a substrate to be processed next, the processing flow from S201 is executed again. However, in this case, the squeegee head 15R is lowered in S203, and the squeegee 1L is replaced with 1R in S204, S206, and S207. Further, screen printing is performed by moving the squeegee 1R in close contact with the metal mask 11 from the right side to the left side in FIG. Thus, the paste supplied by screen printing using the squeegees 1L and 1R alternately is always ahead of the direction of travel of the squeegee that is in close contact with the metal mask, and the paste is effective. Can be used for

  Next, some specific examples of the configuration of the pair of squeegee units 120L and 120R will be described.

  First, a first example of the structure of the squeegee unit 120L will be described with reference to FIG. 5A. The structure of the squeegee unit 120R is basically the same as that of the squeegee unit 120L. The squeegee 1L is fixed to the squeegee holder 3L by the squeegee holder pressing plate 4L so as to incline in the opposite direction to the printing direction 2. The squeegee holder 3L supports the squeegee 1L at a predetermined angle with respect to the printing mask surface 5, the printing surface of the substrate 6, or the substrate support surface (upper surface) of the substrate support table (231 in FIG. 3). A squeegee mounting surface 7L is provided. In the squeegee 1L, an arcuate concave portion 8L is formed at the corner of the squeegee 1L that contacts the printing mask (metal mask) 11 at the tip.

  When printing, the paste 9 first comes into contact with the paste initial contact surface 10L of the squeegee, which is essentially perpendicular to the angle of the mounting surface 7L of the squeegee 1L. The paste 9 is inserted into the print mask opening 12 formed in the substrate 11. Further, the paste 9 rolls at the arc-shaped concave portion 8L at the tip of the squeegee, and reaches the electrode pad 13 on the substrate 6 through the pattern opening 12 of the printing mask formed on the metal mask 11 until the paste 9 reaches the electrode pad 13 on the substrate 6. Is filled. The printed material 6 is covered with a solder resist 14 other than the predetermined pattern opening of the electrode pad 13.

  The paste 9 rolls at the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface of the tip of the squeegee 1L and reaches the electrode pad 14 on the substrate 6 through the pattern opening 12 of the printing mask. This will be described in detail with reference to FIGS. 5B and 5C.

  First, referring to FIG. 5B, when the squeegee 1L is moved in the direction of the arrow 2 while pressing the squeegee 1L against the metal mask 11, the paste 9 has an arc shape in which a liquid repellent film 103 is formed on the surface of the squeegee tip. The state of filling the electrode pad 13 on the substrate 6 through the pattern opening 12 of the printing mask formed on the metal mask 11 from the concave shape portion 8L is arranged in time series from (a) to (e). This will be schematically described.

  (A) shows that the arcuate concave portion 8L having the liquid-repellent film 103 formed on the surface of the tip of the squeegee 1L has not yet reached the pattern opening 12 of the printing mask formed on the metal mask 11. Indicates the state. When the corner 81L at the tip of the squeegee 1L is pressed in the direction of the arrow 2 while being pressed against the surface 5 of the metal mask 11, the paste 9 supplied to the front of the squeegee 1L in the traveling direction is the initial paste contact surface of the squeegee 1L. It is pushed by 10L and moves in the same direction as the squeegee 1L, and part of the squeegee 1L protrudes toward the metal mask 11 at the tip of the arc-shaped concave portion 8L having a liquid-repellent film 103 formed on the surface of the tip. The corner portion of the tip of the squeegee 1L that enters the arcuate concave portion 8L from the gap G between the corner portion 82L and the metal mask 11 (a) and is pressed against the surface 5 of the metal mask 11 The initial contact surface of paste of the squeegee 1L from the gap G along the upper surface of the arc-shaped concave portion 8L on which the liquid-repellent film 103 is formed on the surface. Is extruded to the side of 0L (c).

  As the squeegee 1L further advances in the direction of the arrow, the corner 82L of the arcuate concave portion 8L at the tip of the squeegee 1L is above the pattern opening 12 of the printing mask formed in the metal mask 11 as shown in FIG. Part of the paste extruded from the gap G toward the paste initial contact surface 10L side of the squeegee 1L along the upper surface of the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface. Is pushed into the pattern opening 12 of the printing mask (D).

  When the squeegee 1L further advances in the direction of the arrow and the arcuate concave portion 8L at the tip of the squeegee 1L reaches above the pattern opening 12 of the printing mask formed in the metal mask 11 as shown in FIG. The pressing force does not act on the pattern opening 12 of the printing mask, and the gap between the corner 82L at the tip of the arcuate concave portion 8L at the tip of the squeegee 1L and the metal mask 11 is the same as in the state (a). The paste 9 that has entered inside the arc-shaped concave portion 8L from G is the initial contact of the squeegee 1L from the gap G along the upper surface of the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface. Extruded to the side of the surface 10L (c).

  As the squeegee 1L further advances in the direction of the arrow, the corner 81L of the arc-shaped concave portion 8L at the tip of the squeegee 1L pressed against the metal mask 11 as shown in (d) is above the pattern opening 12 of the printing mask. When it reaches, a part of the paste hitting the corner 81L inside the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface is pushed into the pattern opening 12 of the printing mask (e). The remainder escapes upward (b) and is pushed out from the gap G along the upper surface of the arc-shaped concave portion 8L to the paste initial contact surface 10L side of the squeegee 1L (c).

  When the squeegee 1L further advances in the direction of the arrow and the corner 81L of the arc-shaped concave portion 8L at the tip of the squeegee 1L passes the pattern opening 12 of the printing mask as shown in (d), screen printing by the pattern opening 12 is performed. Ends.

  Here, in FIG. 5B (b), the paste rolls inside the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface, and a part thereof is inside the pattern opening 12 of the printing mask. The state of being pushed in will be described in more detail with reference to FIG. 5C.

  In FIG. 5C, the change in the relative position of the paste 9 with respect to the squeegee 1L in the arc-shaped concave portion 8L in which the liquid repellent film 103 is formed on the surface of the tip of the squeegee 1L is indicated by an arrow. Note that (A) to (G) attached to the arrow indicating the movement of the paste 9 in FIG. 5C is not directly related to (A) to (E) described in FIG. 6B.

  When the edge portion 81L at the lower end of the squeegee 1L is driven by the squeegee driving mechanism 130 in a state where the edge portion 81L is pressed against the metal mask 11, the paste 9 supplied in front of the squeegee 1L is A liquid-repellent film 103 was formed on the surface from the gap G between the end 82L of the recess 8L formed on the squeegee 1L from the position opposite to the side in contact with the metal mask 11 and the metal mask 11. It enters the inside of the recess 8L (b). When the squeegee 1L further advances in the direction of the arrow 2, the paste 9 that has entered the recess 8L is pushed upward at the end 81L because the end 81L of the recess 8L is in contact with the metal mask 11 (c). And pushed back in the opposite direction (d). When the squeegee 1L further advances in the direction of the arrow 2, the paste 9 flows downward in the direction of the end 82L along the liquid repellent film 103 formed on the wall surface of the recess 8L (e), and the tip of the end 82L Part of the opening 12 is pressed into the opening 12 formed in the metal mask 11 (f), the opening 12 is filled with the paste 9, and the electrode pad on the substrate 6 is printed. 13 is connected. The paste 9 that could not enter the opening 12 is discharged from the gap G between the end portion 82L and the metal mask 11 to the paste initial contact surface 10L side of the squeegee (g). That is, the paste 9 entering the inside of the recess 8L rolls inside the recess 8L and is discharged again to the outside of the recess 8L.

  Thus, when the squeegee 1L advances in the direction of the arrow 2, the paste 9 that has entered the recess 8L from the gap G between the end portion 82L of the recess 8L formed in the squeegee 1L and the metal mask 11 is: When the liquid repellent film 103 is formed on the surface and rolled inside the concave portion 8L and discharged from the gap G between the end portion 82L and the metal mask 11 to the outside of the concave portion 8L, a part of the metal is metal. By being pushed into the opening 12 formed in the mask 11, the paste is reliably filled into the opening 12.

  The printing mask 110 used for printing arranges the metal plate 11 in the space in the printing mask plate frame 22, and the metal plate 11 is disposed between the metal plate 11 and the printing mask plate frame 22 over the entire circumference. It is a combination mesh type supported by the printing mask plate frame 22 in a tensioned state via a tension mesh (not shown) provided.

  The printing mask 110 is used for printing by forming a predetermined pattern of openings 12 in the effective printing area corresponding to the moving area of the squeegee 1L moved on the metal plate 11, and making a plate. It is.

  A squeegee mechanism in the printing apparatus 100 equipped with the squeegee according to the first embodiment will be described with reference to FIG. As described with reference to FIG. 5A, the squeegee holder 3L to which the squeegee 1L is fixed is fixed to the squeegee head 15L and installed so that the other squeegee head 15R forming a pair that moves independently faces each other. The squeegee heads 15L and 15R set angles using squeegee holder mounting angle setting jigs 20L and 20R in order to obtain a predetermined attack angle between the surface 5 of the metal mask 11 and the squeegees 1L and 1R. 3L and 3R are fixed by squeegee holder fixing jigs 16L and 16R.

  A squeegee tip structure according to the first embodiment mounted on the printing apparatus 100 will be described with reference to FIG. The squeegee 1L is attached to the squeegee holder 3L (see FIG. 5) at an attachment angle 17 (an angle with respect to the horizontal direction). In Example 1, the attachment angle 17 of the squeegee 1L to the squeegee holder 3L was set between 30 ° and 45 °. At the tip of the squeegee 1L, an arcuate concave portion 8L is formed at a corner 81 in contact with the printing mask 11. The arc-shaped concave shape portion 8L is formed when the squeegee 1L is attached to the squeegee holder 3L at the attachment angle 17L and the corner portion 81 is brought into contact with the print mask 11, and the printing mask of the arc-shaped concave shape portion 8L. 11 is formed such that a gap G is formed between the other end 82 </ b> L protruding toward the side 11 and the surface 5 of the printing mask 11.

As described with reference to FIGS. 5B and 5C, the paste 9 rolled inside the arc-shaped concave portion 8L having the liquid-repellent film 103 formed on the surface is the other end 82L of the arc-shaped concave portion 8L. In order to generate a force to press the squeegee 1L when it is discharged to the paste initial contact surface 10L side of the squeegee 1L through the gap G between the squeegee 1 and the surface 5 of the printing mask 11, when passing through the gap G It is necessary to create a downward flow in paste 9. For this purpose, as a condition for the other end 82L of the arc-shaped concave portion 8L, the angle θ _L of the tangent to the arc-shaped concave portion 8L at the other end 82L shown in FIG. What is necessary is just to form the arc-shaped concave shape part 8L so that it may become the value of the range of 80 to 80 degree | times.

  The initial contact surface 10L of the squeegee, which is essentially perpendicular to the angle 17L of the squeegee 1L attached to the squeegee holder 3L, the printing mask surface 5 (squeegee contact surface), the printing surface of the substrate 6 or the substrate support table 231. The angle with the substrate 6 support surface is a paste initial contact surface angle 18L. In Example 1, the paste initial contact surface angle 18L is between 45 ° and 60 °.

  On the other hand, at a position 81L where the squeegee 1L is in contact with the print mask 11, the angle between the squeegee 1L and the squeegee contact surface of the print mask surface 5 is an attack angle 19L. In the first embodiment, the printing state is verified by swinging the attack angle 19L.

The paste 9 can be inserted into the pattern opening 12 formed in the print mask 11 at the same time as the paste 9 is coated on the surface 5 of the print mask 11 using the paste initial contact surface angle 18L. Further, the paste 9 is forcibly rolled inside the arcuate concave portion 8L in which the liquid repellent film 103 is formed on the surface of the tip of the squeegee 1L, and the pattern opening formed in the printing mask 11 on the paste 9 A force is applied in a direction perpendicular to the portion 12, and the paste 9 can be filled until it reaches the electrode pad 13 on the substrate 6 through the pattern opening formed in the printing mask 11 at the attack angle 19L.
A feature of the squeegee 1L of the present embodiment is that it has an arc-shaped concave portion 8L having a liquid-repellent film 103 formed on the surface at the tip of the squeegee 1L, and has an attack angle 19L compared to the paste initial contact surface angle 18L. It is small. The squeegee 1R also has the same effect as that of the squeegee 1L by providing the arcuate concave portion 8R having a liquid repellent film 103 formed on the surface at the tip.

  As pastes used in the verification experiment of Example 1, (A): LF-204-15 (manufactured by Tamura Chemical Co., Ltd., solder particle size: 1 to 12 μm) and (B): M705-BPS7-T1J ( Using a resin squeegee made of urethane as a main component, using a resin squeegee made of urethane as a main component, manufactured by Senju Metal Industry Co., Ltd., and having a diameter of 50 μm to 200 μm on a 70 μm thick metal plate Screen printing was performed using a metal mask in which the pattern opening 12 was formed.

  The squeegee 1 is inclined in the direction opposite to the printing direction, the squeegee holder mounting angle of the squeegee 1 is between 30 ° and 45 °, and the paste initial contact surface angle 18 (the direction of the squeegee surface where the squeegee precedes and contacts the paste) Angle) was in the range of 45 ° to 60 °.

  As a squeegee used for the verification, a liquid repellent film 103 is formed on the surface produced in this embodiment with the same shape, and a liquid repellent film is formed on the surface. Comparison was made using a squeegee that was not repellent and not repellent.

In the pattern opening 12, the value (4H with a diameter as shown in FIG. 5A divided by the area of the area (πDH) the pattern opening of the wall depth of the pattern opening 12 of the H in D (πD ^2/4) / D) is the print difficulty index. That is, the goal was that the printing difficulty index is 2.8 or more and the paste can be transferred satisfactorily.

  As a result of the experiment, when the above-described (A) is used as the paste, the paste 9 becomes smaller when the gap G between the squeegee tip 82L that is not in contact with the printing mask 11 and the printing mask surface 5 becomes smaller than 0.12 mm. Was prevented from flowing into the arcuate concave portion 8 formed at the tip of the squeegee, and the amount of paste transferred was reduced. This phenomenon was more noticeable when printing was performed with a squeegee that had not been subjected to a liquid repellent treatment.

  When (B) is used as the paste, when the gap G between the squeegee tip 82 that does not contact the print mask 11 and the print mask surface 5 becomes smaller than 0.06 mm, the paste 9 becomes the squeegee tip. The amount of paste to be transferred was reduced by inhibiting the fluid from flowing into the arc-shaped concave portion 8 formed in the above. This phenomenon also appears more conspicuously when printing is performed with a squeegee that has not been subjected to a liquid repellent treatment.

  On the other hand, if the gap G between the squeegee tip 82L that is not in contact with the print mask 11 and the print mask surface 5 is larger than 1 mm, the paste may be confined in the arcuate concave portion 8 formed at the squeegee tip during printing. It became impossible to leak from the arcuate concave portion 8 and the force applied to the paste 9 filling the pattern opening 12 of the printing mask 11 was weakened, so the filling amount and the transfer amount were insufficient. This phenomenon also appears more conspicuously when printing is performed with a squeegee that has not been subjected to a liquid repellent treatment.

  However, the gap G of 1 mm is due to the shape of the arc-shaped concave portion 8 formed at the tip of the squeegee, and in the case of the squeegee 1 used in the experiment, 1 mm was the limit. Even if G is 1 mm or more, the direction of the tangent of the tip 82 of the arcuate concave portion 8 faces the direction of the print mask surface 5 and there is a space for partially confining the paste 9 inside the arcuate concave portion 8. If it is possible, the paste can be confined in the arcuate concave portion 8, and a sufficient amount of filling and transfer can be performed.

  As a result of this experiment, in a state where one of the arc-shaped concave portions 8L formed at the tip of the squeegee is in contact with the print mask surface 5, the other 82L of the arc-shaped concave portion 8L at the tip of the squeegee and the print mask surface 5 are obtained. It can be seen that the gap G between the first and second pastes needs to be at least 10 times the average particle size of the paste used. The other of the arcuate concave portion 8L at the tip of the squeegee means a tip 82L that is a concave shape processed into an arc shape at the tip of the squeegee and is not in contact with the print mask surface 5.

  In any case, the transfer amount of the squeegee with liquid repellency produced in this example was larger than that of the squeegee without liquid repellency treatment. This is because, since the squeegee surface of the arc-shaped concave portion 8 formed at the tip of the squeegee has liquid repellency, the rolling property of the paste 9 is not hindered and the viscosity of the paste 9 is kept low. It is thought that this was a factor.

  Further, as a comparative example, a printing experiment was performed using a squeegee that is not processed at the tip of the squeegee and a squeegee that is subjected to linear oblique polishing as shown in FIG. Even in this case, a comparative study was performed using a squeegee having the same shape and liquid repellency and a squeegee not subjected to liquid repellency treatment.

  As a result, in the case of using the squeegee that is not processed at the tip portion shown in FIG. 8B, good pattern printing could not be performed unless the diameter of the pattern opening 12 was 150 μm or more. In the squeegee with liquid repellency, the slip of the paste 9 on the surface of the squeegee is improved, the filling amount into the opening 12 of the printing mask 11 is reduced, and the printability is worse than that of the squeegee not having liquid repellency. Unless it was 180 μm or more, good pattern printing could not be performed.

  Further, when a squeegee having a tip end processed as shown in FIG. 8C, good pattern printing could not be performed unless the diameter of the pattern opening 12 was 120 μm or more. In this case, even with a squeegee imparted with liquid repellency, the filling amount into the opening 12 of the printing mask 11 is good and the liquid repellency is imparted even though the slip of the paste 9 on the squeegee surface has improved. Although printability equivalent to that of a non-squeegee was obtained, good pattern printing could not be performed unless the thickness was 120 μm or more.

  On the other hand, when printing is performed using a squeegee in which concave shapes are formed on a plurality of surfaces as shown in FIG. 8D, the cross section according to the present embodiment shown in FIG. A result almost the same as that obtained when printing was performed using a squeegee was obtained, and all the patterns of the pattern openings 12 having a diameter of 50 μm to 200 μm formed on the metal mask could be satisfactorily screen printed. The squeegee to which liquid repellency was imparted was better because the transfer amount was larger and the variation in the transfer amount was smaller than the squeegee not subjected to the liquid repellent treatment.

  As described above, by mounting the squeegee of the first embodiment on the printing apparatus, the paste 9 can be printed accurately and stably regardless of the size of the opening area of the opening of the printing mask 11. For this purpose, the tip of the squeegee is processed into a special shape, and at least liquid repellency is imparted to the tip of the squeegee that the paste 9 contacts, so that the pattern opening 12 of the printing mask 11 having a desired opening is obtained. When the paste 9 is filled and the paste 9 is transferred to the printing material, the rolling of the paste 9 is promoted, the filling property of the paste 9 into the opening 12 of the printing mask 11 is promoted, and the printing mask 11 with respect to the paste 9 is promoted. It was possible to apply a force for filling the opening 12 in the vertical direction.

  In the example described above, the concave portion 8 is formed at one corner of the tip of the squeegee 1. However, the present embodiment is not limited to this, and for example, as shown in FIG. Any configuration may be used. In the configuration shown in FIG. 9, the squeegee 1 ′ is attached to the squeegee holder 3 by the squeegee holder pressing plate 4 as shown in FIG. 5A, and the front surface of the squeegee 1 is parallel to the printing mask 11. 90, and a concave portion 98 having the structure described with reference to FIGS. 5A to 7 is formed between the surface 90 and the paste initial contact surface 10 from one end 981 of the surface 90 to the end surface 982 of the paste initial contact surface 10. Formed. Thus, by forming the surface 90, the contact area between the printing mask 11 and the squeegee 1 ′ can be increased, and the deformation amount of the concave portion 98 due to wear of the squeegee 1 ′ can be reduced, and the squeegee 1 ′. It is possible to extend the service life.

  Alternatively, the surface 90 may be formed to be slightly inclined with respect to the printing mask 11 so that only one end 981 of the surface 90 is in contact with the printing mask 11.

Example 2 is the same as Example 1 except that SiO ₂ or a fluororesin is used as the liquid repellent film 103 formed on the surface of the squeegee 1.

First, SiO ₂ was used as the liquid repellent film 103 formed on the surface of the squeegee 1. An alkoxysilane-containing solution was applied by spraying to at least a portion of the squeegee 1 that was in contact with the paste 9. Thereafter, by drying, SiO ₂ having liquid repellency could be formed on the surface of the squeegee 1.

The film | membrane produced | generated from the alkoxysilane used here was not contaminated with the various solvent contained in the paste 9, was stable, and was excellent in the liquid repellency with respect to water or a solvent.
Here, the spray method is used as the film formation method, but it is possible to form the liquid-repellent film 103 by applying an alkoxysilane-containing solution by an aerosol deposition method or a dip method and drying. .

In this manner, the squeegee 1 used in Example 2 having the liquid-repellent film 103 made of SiO ₂ at least at the portion where the paste 9 is in contact could be produced.

Next, a fluororesin was used as the liquid repellent film 103 formed on the surface of the squeegee 1. A copolymer (PFA) of tetrafluoroethylene and perfluoroalkoxyethylene was mixed with a urethane resin at least in a portion where the paste 9 was in contact with the squeegee 1 and applied by a spray method. A film in which a copolymer (PFA) of tetrafluoroethylene and perfluoroalkoxyethylene having liquid repellency is uniformly dispersed on the entire surface of the squeegee 1 by heating and curing with a temperature profile similar to that of the squeegee. Could be formed.

In addition to PFA, there are PTFE, FEP, ETFE, etc. as fluororesins having liquid repellency. Tetrafluoroethylene and perfluoroalkoxy have excellent organic solvent resistance, a large contact angle, and a small friction coefficient. A film made of a copolymer with ethylene (PFA) was the best.

Here, as a method of forming a film having a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene, it was mixed with a urethane resin, applied by a spray method, and heated and cured to form a liquid repellent film 103. However, the liquid-repellent film 103 can be formed by applying and curing by a dip method.

In this way, the squeegee 1 used in the present Example 2 having the liquid repellent film 103 in which the copolymer of tetrafluoroethylene and perfluoroalkoxyethylene is dispersed at least at the portion where the paste 9 is in contact is prepared. Was made.

  The result of verifying the printing status in Example 2 was almost the same as the result of verifying the printing status in Example 1.

  As described above, the printing apparatus equipped with the squeegee 1 used in the second embodiment can accurately and stably print the paste regardless of the size of the opening area of the opening 12 of the printing mask 11. For this purpose, the tip of the squeegee is processed into a special shape, and at least liquid repellency is imparted to the tip of the squeegee that the paste 9 contacts, so that the opening pattern portion 12 of the printing mask 11 having a desired opening is obtained. When the paste is filled and the paste is transferred to the substrate, the rolling of the paste is promoted, the filling property of the paste into the opening 12 of the printing mask 11 is promoted, and the opening 12 of the printing mask 11 with respect to the paste. It was possible to add a filling force in a substantially vertical direction.

  The third embodiment is the same as the first and second embodiments except that a mesh mask is used as the print mask 11.

  In the third embodiment, a mesh is used for the print mask 11. As the mesh, # 325 plain weave using a high-strength wire having a wire diameter of 16 μm and a thickness of 35 μm was used. A mesh mask in which a pattern opening having a diameter of 50 μm to 200 μm was formed by using an emulsion having a thickness of 35 μm and a thickness of 55 μm was used for this mesh.

  In order to separate the printing mask 11 from the substrate 6 using mesh tension, the tension of the printing mask was set to 0.2 mm or less (measured with a tension gauge STG-80NA manufactured by Protech Co., Ltd.).

  The metal mesh used for the printing mask 11 used in the third embodiment has an opening ratio of 40% or more, and the wire diameter used for the metal mesh needs to be smaller than half the opening width of the metal mesh.

In the pattern opening 12 formed in a mesh mask (see FIG. 6A), divided by the area of the pattern opening an area of the wall surface of the pattern opening ^{12 (πDH) (πD 2/} 4) (4H / D) printing It is a difficulty index. That is, the target of the third embodiment is that the printing difficulty index is 2.8 or more and the paste can be transferred satisfactorily.

  In the third embodiment, since there is a gap between the mesh mask and the substrate 6, unlike the contact printing using the metal mask used in the first and second embodiments, one of the arc-shaped concave portions 8 </ b> L formed at the tip of the squeegee. In a state where 81L (see FIG. 8A) is in contact with the surface 5 of the print mask 11, the mesh mask is not horizontal but inclined. Therefore, the gap G between the other 82L of the arcuate concave portion 8L at the tip of the squeegee 1L and the print mask surface 5 is reduced.

  The gap G (see FIG. 8A) between the other 82L of the arcuate concave portion 8L at the tip of the squeegee and the print mask surface 5 needs to be 10 times or more the average particle size of the paste to be used. The other of the arcuate concave shape portion 8 at the tip of the squeegee means the tip portion 82L that is not in contact with the mesh mask in the concave shape portion 8L processed into an arc shape at the tip of the squeegee 1L.

  Since the particle size of the solder particles of the paste 9 used in the third embodiment is 12 μm or less as in the first and second embodiments, the squeegee tip 82 that does not contact the mesh mask and the print mask surface 5 The gap G was set to 0.6 mm. When the squeegee comes into contact with the mesh mask, it not only fills the mesh mask opening with paste, but also discharges to the substrate side of the mesh mask, and then the tip of the squeegee that originally contributes to printing is the mesh mask opening. When it reached, the situation was printed twice. For this reason, the paste oozes out between the mesh mask and the substrate to be printed, resulting in bleeding.

  When LF-204-15 of (A) is used as the paste, when the gap between the tip 82L of the squeegee 1L not contacting the mesh mask and the printing mask becomes smaller than 0.12 mm, the paste 9 becomes squeegee. The amount of paste to be transferred was reduced by inhibiting the flow into the arcuate concave portion 8L formed at the tip of 1L.

  Further, when M705-BPS7-T1J of (B) is used, when the gap G between the squeegee tip 82L that is not in contact with the mesh mask and the print mask surface 5 becomes narrower than 0.06 mm, the paste becomes squeegee 1L. The amount of paste to be transferred was reduced by preventing the fluid from flowing into the arcuate concave portion 8 formed at the tip.

  On the other hand, if the gap G between the tip portion 82 of the squeegee 1L that is not in contact with the mesh mask and the print mask surface 5 is larger than 1 mm, the paste is put into the arc-shaped concave portion 8L formed at the tip of the squeegee 1L during printing. It was impossible to confine, leaking out from the arcuate concave portion 8, and the force applied to the paste filling the pattern opening 12 of the mesh mask was weakened, so the filling amount and the transfer amount were insufficient.

  However, the gap G of 1 mm is due to the shape of the arc-shaped concave portion 8L formed at the tip of the squeegee. In the case of the squeegee 1L used in the experiment, 1 mm was the limit. Even if G is 1 mm or more, the direction of the tangent to the tip 82L of the arcuate concave portion 8L is directed toward the print mask surface 5, and there is a space for partially confining the paste 9 inside the arcuate concave portion 8L. If completed, the paste can be confined in the arc-shaped concave portion 8L, and a sufficient amount of filling and transfer can be performed.

  In any case, the squeegee provided with the liquid repellency produced in Examples 1 and 2 had a larger transfer amount than the squeegee not subjected to the liquid repellency treatment. This is because, since the squeegee surface of the arc-shaped concave portion 8 formed at the tip of the squeegee has liquid repellency, the rolling property of the paste 9 is not hindered and the viscosity of the paste 9 is kept low. It is thought that this was a factor.

  In the third embodiment, a printing machine in which equivalent squeegees 1L and R are arranged on the left and right sides has been examined, but in a printing machine using a mesh mask, one of the pastes 9 is applied to the opening 12 and the printing mask surface 5 of the printing mask 11. There is a printing machine equipped with a scraper (not shown) used for coating. The scraper used here is often a stainless plate-like one, and depending on the paste 9 used, the paste 9 may adhere to the scraper and drop the paste 9 onto the printing mask 11 during the operation. Sometimes it was necessary. Similar to the squeegee 1 produced in Examples 1 and 2, by applying liquid repellency to the surface of the scraper, it was not necessary to remove the paste. Further, by forming urethane resin at the tip of the scraper with which the paste 9 is in contact, damage to the print mask surface 5 by the scraper could be reduced. Furthermore, the damage to the print mask surface 5 was further reduced by imparting liquid repellency to the urethane resin at the tip of the scraper.

  The result of verifying the printing status in Example 3 was the same as the result of verifying the printing status in Examples 1-2. That is, all the patterns of the pattern openings 12 having a diameter of 50 μm to 200 μm formed on the mesh mask could be satisfactorily screen printed.

  As described above, by mounting the squeegee of Embodiments 1 and 2 on the printing apparatus, the paste 9 can be printed accurately and stably regardless of the size of the opening area of the opening 12 of the printing mask 11. it can. For this purpose, the tip of the squeegee is processed into a special shape, and at least liquid repellency is imparted to the tip of the squeegee that the paste 9 contacts, so that the pattern opening 12 of the printing mask 11 having a desired opening is obtained. When the paste 9 is filled and the paste 9 is transferred to the printing material, the rolling of the paste 9 is promoted, the filling property of the paste 9 into the opening 12 of the printing mask 11 is promoted, and the printing mask 11 with respect to the paste 9 is promoted. It was possible to apply a force for filling the opening 12 in the vertical direction.

  A squeegee structure mounted on the printing apparatus according to the fourth embodiment will be described with reference to FIGS. 10 and 11. The squeegee 71 used in this Example 4 was a flat squeegee and a squeegee 71 inserted in the center of the squeegee using a glass epoxy resin plate 727 as a support.

  In addition, as a squeegee used for verification, a squeegee having the same shape and having liquid repellency produced in this example and a squeegee not subjected to liquid repellency treatment were compared and examined.

  FIG. 11 shows a schematic diagram of the tip shape of the squeegee 71 used in the fourth embodiment. FIG. 11 is an enlarged view of the main part of the squeegee structure, taking a flat squeegee as an example in order to explain the tip shape of the squeegee 71. Therefore, the squeegee surface treatment status is not shown.

  In Example 4, the squeegee 71 was attached in the direction opposite to that in Examples 1 to 3, and the squeegee 1 was inclined in the same direction as the printing direction 2. Except for changing the shape of the squeegee 71, it is the same as the first and second embodiments.

  The configuration of the printing apparatus used in the fourth embodiment is basically the same as the configuration described in FIG. 4, and the squeegee units 120L and 120R in FIG. 4 are configured as shown in FIG. Since it is a thing replaced with a thing, description of a whole block diagram is abbreviate | omitted.

  When attaching the squeegee, depending on the printing device used, the squeegee 1 is inclined in the direction opposite to the printing direction 2 as in Examples 1 to 3, and the squeegee 71 is inclined in the printing direction 2 as in Example 4. There is a case to do.

  When the squeegee 1 is inclined in the direction opposite to the printing direction 2 as in the first to third embodiments, the surface 10 (see FIG. 8) of the squeegee 1 with which the paste 9 contacts and the mounting angle 17 of the squeegee 1 are substantially equal. It is vertical. On the other hand, in the fourth embodiment, as shown in FIG. 11, when the squeegee 71 is inclined in the printing direction 2, the angle 718 of the surface 710 of the squeegee 71 in contact with the paste 9 to the print mask surface 5 and the attachment of the squeegee 71. Angle 717 is substantially the same.

  Also in this embodiment, as shown in FIG. 10, printing is performed by using a squeegee 71 to transfer paste 9 from a printing mask 11 having an opening 12 at a predetermined position to a predetermined position of a substrate 6 fixed on a table 231. In the apparatus, one corner of the tip of the squeegee 71 has an arcuate concave shape 78, and an attack angle 719 (see FIG. 11) between the squeegee 71 and the printing surface of the substrate 6 from the attachment angle 718 of the squeegee 71. It is characterized by making it smaller.

  Thereby, the paste is confined in the arc-shaped concave shape 78 at the tip of the squeegee 71, and squeezing (the squeegee 71 slides in the printing direction while applying pressure (printing pressure) to the screen surface of the print mask 11). The paste 9 was able to roll along the arcuate concave portion 78 at the tip of the squeegee 71 in the process of.

The squeegee used in Example 4 was a resin mainly composed of urethane.
As shown in FIG. 11, when the attachment angle 717 of the squeegee 71 is reduced in order to reduce the attack angle 719, the squeegee head 715 that applies the printing pressure and the portion 781 where the tip of the squeegee 71 contacts the print mask surface 5 are relative to each other. Therefore, the printing pressure was not effectively applied to the tip of the squeegee 71. That is, when a relative displacement occurs in the force point, a rotational moment works. In this case, the higher the printing pressure, the more the squeegee tip has a force in the direction opposite to the printing pressure.

  Therefore, the contact point 781 is positioned directly below the squeegee head 715 so that the contact point 781 between the direction in which the printing pressure is applied to the squeegee head 715 and the print mask surface 5 at the tip of the squeegee 71 are arranged in substantially the same straight line. Adjusted.

  In the fourth embodiment, one of the arc-shaped concave portions 78 formed at the tip of the squeegee 71 is in contact with the print mask 11 and the other 782 of the arc-shaped concave portion 78 at the tip of the squeegee 71 is printed. As in the case described in Example 1, the gap G with the mask surface 5 needs to be 10 times or more the average particle diameter of the paste 9 to be used and 1 mm or less. The other side of the arcuate concave portion 78 at the tip of the squeegee 71 means a tip portion 782 that is not in contact with the printing mask surface 5 by the concave portion 78 processed into an arc shape at the tip of the squeegee 71.

  When a material having a particle size of 12 μm or less is used as the solder particles of the paste 9 used in the fourth embodiment, the gap G between the squeegee tip 782 that is not in contact with the print mask 11 and the print mask surface 5 is set to 0. 3 mm. When the squeegee 71 comes into contact with the print mask 11, the squeegee not only fills the opening 12 of the print mask 11 but also discharges it to the substrate 6 side of the lower surface of the print mask 11, and then contributes to printing. When the leading edge of the ink reached the opening 12 of the printing mask 11, it was printed twice. For this reason, the paste oozes out between the printing mask 11 and the substrate 6 to cause bleeding.

  When A used in Example 1 is used as the paste, when the gap G between the squeegee tip 782 that is not in contact with the print mask 11 and the print mask surface 5 becomes narrower than 0.12 mm, the paste becomes the tip of the squeegee. The amount of paste to be transferred was reduced by inhibiting the fluid from flowing into the arc-shaped concave portion 8 formed in the above.

When B used in Example 1 is used as the paste, when the gap G between the squeegee tip 782 that is not in contact with the print mask 11 and the print mask surface 5 becomes smaller than 0.06 mm, the paste 9 The amount of paste to be transferred was reduced by inhibiting the flow into the arcuate concave portion 78 formed at the tip of the squeegee.
On the other hand, when the gap G between the tip portion 782 of the squeegee 71 not contacting the print mask 11 and the print mask surface 5 is larger than 1 mm, the paste is confined in the arc-shaped concave portion 78 formed at the tip of the squeegee during printing. As a result, leakage from the arc-shaped concave portion 78 and the force applied to the paste 9 filling the pattern opening 12 of the printing mask 11 are weakened, so that the filling amount and the transfer amount are insufficient.

  However, this gap G of 1 mm is due to the shape of the arc-shaped concave portion 78 formed at the tip of the squeegee, and in the case of the squeegee 71 used in the experiment, 1 mm was the limit. Even if G is 1 mm or more, the direction of the tangent of the tip 782 of the arc-shaped concave portion 78 faces the direction of the print mask surface 5, and there is a space for partially confining the paste 9 inside the arc-shaped concave portion 8L. If possible, the paste can be confined in the arc-shaped concave portion 78, and a sufficient amount of filling and transfer can be performed.

  In Example 4, as in Examples 1 and 2, the printing mask 11 was formed by forming a pattern opening 12 having a diameter of 50 μm to 200 μm on a metal plate having a thickness of 70 μm. In the third embodiment, the squeegee 71 is inclined in the same direction as the printing direction 2, the attachment angle 717 of the squeegee 71 to the squeegee holder 73 is 70 °, and the paste initial contact surface angle 718 (the squeegee 71 precedes). The angle in the direction of the surface of the squeegee 71 in contact with the paste 9 was set to 70 °, which is substantially the same as the mounting angle 717 to the squeegee holder 73. The angle between the squeegee 71 and the squeegee contact surface of the printing mask 11 was examined by changing the attack angle 719. As for the printing status, the filling property of the printing mask 11 into the pattern opening 12 and the transfer property to the substrate were verified.

  The result of verifying the printing status in Example 4 was slightly inferior to the result of verifying the printing status in Examples 1 to 3, but almost the same results were obtained as printability. In particular, in the squeegee 71 in which diamond-like carbon or fluorine group-containing diamond-like carbon was formed as the liquid-repellent film 103, the printing situation was verified because the liquid-repellent portion in contact with the paste was slightly inferior. The result is considered to be slightly inferior. In addition, since the distance between the electrode and the squeegee surface at the time of film formation is wide and the liquid repellent film 103 is not sufficiently attached to the bottom of the squeegee, the diamond-like carbon on the squeegee 71 There is a concern that the adhesiveness of fluorine-containing diamond-like carbon is weak.

  In any case, in the squeegee 71 used in Example 4, the squeegee to which liquid repellency was imparted had a larger transfer amount than the squeegee not subjected to liquid repellency treatment. This is because, since the squeegee surface of the arc-shaped concave portion 8 formed at the tip of the squeegee has liquid repellency, the rolling property of the paste 9 is not hindered and the viscosity of the paste 9 is kept low. It is thought that this was a factor.

  As a comparative experiment of Example 4, using the squeegee 1 whose tip portion was processed into various shapes as in the case described with reference to FIG. 9, as shown in FIG. The squeegee was inclined in the same direction as the printing direction 2. Except for changing the shape of the squeegee as shown in FIG. 11, the configuration is the same as that described in FIGS.

  In the comparative experiment, a printing experiment was also performed using a squeegee that was not processed at the tip of the squeegee and a squeegee that was subjected to linear oblique polishing as shown in FIG. Even in this case, a comparative study was performed using a squeegee having the same shape and liquid repellency and a squeegee not subjected to liquid repellency treatment. The shape of the squeegee 1 shown in FIG. 12A is the same as that described with reference to FIGS.

  As a result of the comparative study, when the squeegee that is not processed at the tip portion shown in FIG. 12B was used, good pattern printing could not be performed unless the diameter of the opening 12 of the pattern was 150 μm or more. In the squeegee with liquid repellency, the slip of the paste 9 on the surface of the squeegee is improved, the filling amount into the opening 12 of the printing mask 11 is reduced, and the printability is worse than that of the squeegee not having liquid repellency. Unless it was 180 μm or more, good pattern printing could not be performed.

  Further, when a squeegee having a tapered tip end was used as shown in FIG. 12C, good pattern printing could not be performed unless the diameter of the pattern opening 12 was 120 μm or more. In this case, even with a squeegee imparted with liquid repellency, the filling amount into the opening 12 of the printing mask 11 is good and the liquid repellency is imparted even though the slip of the paste 9 on the squeegee surface has improved. Although printability equivalent to that of a non-squeegee was obtained, good pattern printing could not be performed unless the thickness was 120 μm or more.

  On the other hand, as shown in FIG. 12D, when printing is performed using a squeegee in which a concave shape is formed on a plurality of surfaces and a space for confining the paste is formed inside, the cross section of FIG. The result was almost the same as when printing was performed using a squeegee having a shape, and all the patterns of the pattern openings 12 having a diameter of 50 μm to 200 μm formed on the metal mask could be satisfactorily screen printed. The squeegee to which liquid repellency was imparted was better because the transfer amount was larger and the variation in the transfer amount was smaller than the squeegee not subjected to the liquid repellent treatment.

  As described above, the printing apparatus equipped with the squeegee 1 used in the fourth embodiment can accurately and stably print the paste regardless of the size of the opening area of the opening 12 of the printing mask 11. For this purpose, the tip of the squeegee is processed into a special shape, and at least liquid repellency is imparted to the tip of the squeegee that the paste 9 contacts, so that the opening pattern portion 12 of the printing mask 11 having a desired opening is obtained. When the paste is filled and the paste is transferred to the substrate, the rolling of the paste is promoted, the filling property of the paste into the opening 12 of the printing mask 11 is promoted, and the opening 12 of the printing mask 11 with respect to the paste. It was possible to add a filling force in a substantially vertical direction.

Example 5 is the same as Examples 1 to 4 except that various pastes are used.
In the printing apparatus of the present invention, the paste to be used is a high-viscosity material in which a solid content and a liquid content are mixed, and the solid content is a solder composition particle, silver particle, flake-shaped silver particle, or particle mainly composed of nickel. The main component is at least one material selected from the group consisting of metal-coated spherical resin particles, ceramic particles, and glass particles. The characteristics and printing results of the object to which these pastes are applied are as follows: Shown in

  The paste using the solder composition particles as a solid content is used for surface mounting technology such as pad bumps of a printed wiring board, and formation of solder connection terminals such as pad bumps of a semiconductor wafer. The shape of the solder composition particles used is approximately spherical.

  The particle size of the solder composition particles can be selected according to the pattern used from about 1 μm to about 30 μm. In this case, the size of the opening pattern 12 formed in the printing mask 11 is set to 10 times or more the particle size of the solder composition particles in consideration of the fluidity of the paste in the opening portion. Good printing similar to that of Embodiments 1 to 5 could be performed.

  That is, when the particle size of the solder composition is 1 μm, the size of the opening pattern needs to be 10 μm or more. When the particle size of the solder composition is 30 μm, the size of the opening pattern needs to be 300 μm or more. In order to form a fine pattern, it is necessary to use particles having a fine particle size solder composition.

  A paste using silver particles as a solid content is used for forming a wiring pattern of a low-temperature fired ceramic, forming an electrode of a solar cell, and the like. The shape of the silver particles used is almost spherical.

  The particle diameter of the silver particles is about 2 nm to about 10 μm. When forming a fine wiring pattern, it is necessary to use particles having a fine particle diameter.

  On the other hand, since the silver paste used for electrode formation of solar cells needs to reduce the wiring resistance of the electrode, it is required to form the wiring pattern with a large thickness and to be fired at a low temperature. It is necessary to use a paste in which particles having a particle size and particles having a particle size of several nm are mixed. If the wiring width is 50 μm, the effective particle size of the silver particles used is 5 μm or less. In this embodiment, since the transferability is improved, it is possible to obtain a good printing result with a high aspect ratio of the wiring pattern and capable of handling fine wiring.

  Further, it is difficult to fill a Si wafer having a penetrating hole with a silver paste with a conventional squeegee, and there is a problem that a cavity remains in the central portion even when filling printing is performed from both sides. By using the squeegee produced in the form of this example, the filling property was improved, and the through hole could be filled with the silver paste. In particular, the tip of the squeegee is processed into a special shape (arc-shaped concave shape), and at least the liquid-repellent film on the tip of the squeegee that comes in contact with the silver paste (a composite film of diamond-like carbon and fluorine-containing diamond-like carbon) In this way, the silver paste could be filled into the through-hole having a diameter of 100 μm formed on the Si wafer having a thickness of 300 μm by one printing.

  In addition, paste using flaky silver particles as a solid content is a conductive conductive adhesive used when components are mounted on a printed wiring board. As electronic components are miniaturized, the paste is applied to a substrate having protruding electrodes. Used for mounting. The flaky silver particles are processed into a foil shape by applying pressure to the silver particles, and are irregularly shaped particles. This paste is characterized in that it does not require much transfer dimension accuracy of the printed pattern in order to ensure conductivity with contact resistance, but in this embodiment, since the discharge property can be improved, it is localized. It was possible to print reliably without causing poor coating.

  A paste using particles containing nickel as a main component as a solid content is used for a capacitor or the like that needs to form an ultra-thin conductor. The particle size of the nickel-based particles is about 10 nm to about 100 nm, and is characterized in that the paste has a low viscosity and has fluidity.

  As the heel thickness decreases, the amount of paste retained decreases. When the discharge amount is increased, it is desirable to increase the thickness. On the other hand, for the formation of fine electrode wiring patterns and capacitor thin film electrodes, it is desirable that the thickness is thinner. When it was necessary to make it thinner than the thickness after weaving, a mesh having a desired thickness was used by rolling the mesh with a roll. It was possible to select the type of mesh (number of meshes, aperture ratio, wire diameter, thickness, etc.) depending on the device to be applied.

  In Example 5, since the ejection properties could be improved, uniform and very thin film pattern formation was possible, and good printing results could be obtained.

  On the other hand, paste that uses spherical resin particles coated with metal as a solid content is an anisotropic conductive paste, and parts for printed wiring boards that allow electrical connection even if resistance is higher than that of display terminals and metal joints Used for mounting. The particle diameter of the resin particles coated with metal is about 10 μm, and the print pattern is characterized in that it is applied to the entire pad portion of the component to be mounted. In the present embodiment, since the dischargeability could be improved, local printing failure did not occur, and good printing results could be obtained.

  Pastes that use ceramic particles as solid content include dielectric pattern formation of low-temperature fired ceramics, insulating pattern formation of electronic circuits, pattern formation of resists for etching on copper-clad polyimide films, pattern formation for insulating layer scribing of solar cells, etc. Used for. In this embodiment, since it has a reliable transfer performance, a local disconnection failure does not occur and a good printing result can be obtained.

  Pastes that use glass particles as a solid content are used for addition to silver paste as a sintering aid, dielectric pattern formation of low-temperature fired ceramics, insulating pattern formation of electronic circuits, and the like.

  Ceramic particles and glass particles are crushed because they are produced by pulverization. In these cases, it is necessary to make the opening pattern of the printing mask used 10 times or more the average particle diameter.

  The squeegee 1 used in the fifth embodiment has a concave-shaped portion 8 in which one corner of the squeegee tip has an arcuate shape, and an angle 18 in the direction of the squeegee surface where the squeegee 1 comes into contact with the paste first (reverse to the printing direction). Squeegee tip in the direction of the squeegee) or the squeegee attachment angle (when the squeegee is tilted in the same direction as the printing direction), the attack angle between the squeegee and the printing surface of the substrate is made smaller and the paste contacts the paste By using a printing apparatus equipped with the squeegee 1 for all of these pastes, the printing mask 11 can be accurately formed regardless of the size of the opening area. It was possible to print stably.

  Thus, the printing apparatus equipped with the squeegee 1 used in the fifth embodiment can accurately and stably print the paste regardless of the size of the opening area of the pattern opening 12 of the printing mask 11. 1 can be mounted. For this purpose, the tip of the squeegee is processed into a special shape, and at least the tip of the squeegee that comes into contact with the paste has liquid repellency, so that the paste on the opening pattern portion 12 of the printing mask 11 having a desired opening can be obtained. During filling and transfer of the paste to the substrate, the rolling of the paste is promoted, the filling property of the paste into the opening 12 of the printing mask 11 is promoted, and the direction substantially perpendicular to the opening 12 of the printing mask 11 with respect to the paste The filling force could be added.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description, and the present invention is not limited to the various embodiments described above without departing from the spirit of the present invention. It encompasses alternatives, modifications or variations.

  DESCRIPTION OF SYMBOLS 1,71 ... Squeegee 3, 73 ... Squeegee holder 5 ... Print mask surface 6 ... To-be-printed object 8, 78 ... Arc-shaped concave shape part of squeegee tip 9 ... Paste 11 ... Print mask 21 ... Control panel 22 ... Plate frame 23 ... Substrate support table section 100 ... printing apparatus 101 ... urethane resin 102 ... core material 103 ... liquid-repellent film 110 ... print mask section 120L, R ... squeegee section 130 ... squeegee drive mechanism section.

Claims (15)

Mask holding means for holding a mask for screen printing;
Table means for placing a sample to be screen printed and moving the sample up and down;
A squeegee means comprising a squeegee for printing a paste pattern on the sample placed on the table means via the mask;
A screen printing apparatus comprising squeegee driving means for reciprocating the squeegee of the squeegee means along the mask,
The squeegee of the squeegee means has a recess formed forward in the movement direction during printing from the position where the squeegee contacts the mask when the squeegee is pressed against the mask. An end of the recess opposite to the side in contact with the mask protrudes toward the mask and is formed so as to open a gap with the mask, and at least the surface of the squeegee tip including the recess has the paste. A screen printing apparatus having repellent liquid repellency. Mask holding means for holding a mask for screen printing;
Table means for placing a sample to be screen printed and moving the sample up and down;
A squeegee means comprising a squeegee for printing a paste pattern on the sample placed on the table means via the mask;
A screen printing apparatus comprising squeegee driving means for reciprocating the squeegee of the squeegee means along the mask,
The squeegee of the squeegee means is driven by the squeegee driving means in a position where the squeegee is in contact with the mask when the squeegee is pressed against the mask and in a state where the squeegee is pressed against the mask during printing. A recess for accumulating the paste is formed between the initial contact surface of the squeegee that first contacts the paste, and the surface of the tip of the squeegee including at least the recess has liquid repellency to repel the paste. A screen printing apparatus.   The concave portion of the squeegee is formed with a space in which the paste rolls inside the concave portion when driven by the squeegee driving means in a state where the squeegee is pressed against the mask during the printing. The screen printing apparatus according to claim 1, wherein the surface of the squeegee tip including the recess has liquid repellency.   The recess of the squeegee has an average particle size of 10 of the particles of the paste between the mask and the end of the recess opposite to the side in contact with the mask when the squeegee is pressed against the mask. 4. The screen printing apparatus according to claim 3, wherein the screen printing apparatus is formed so as to open a gap more than double, and the surface of the tip of the squeegee including the recess has liquid repellency.   The squeegee is formed of a resin having urethane as a main component and having a hardness of 80 degrees or more, and at least the surface of the tip of the squeegee including the recess has liquid repellency. 5. The screen printing apparatus according to 4.   The squeegee is formed of a conductive material as a core material, and the periphery of the core material is formed of a resin mainly composed of urethane, and at least the surface of the tip portion of the squeegee including the recess has liquid repellency. The screen printing apparatus according to claim 1, wherein the screen printing apparatus is provided. The portion of the squeegee tip having a liquid-repellent surface is formed with a film made of at least one material selected from SiO ₂ , fluororesin, hydrocarbon, and fluorine group-containing hydrocarbon on the surface. The screen printing apparatus according to claim 1, wherein the screen printing apparatus is provided.   3. The screen printing apparatus according to claim 1, wherein a diamond-like carbon film is formed on a surface of the squeegee having a liquid repellent surface.   3. The screen printing according to claim 1, wherein a fluorine-containing diamond-like carbon film is formed on a surface of the squeegee at a tip end surface having liquid repellency. 4. apparatus.   The portion of the squeegee tip having a liquid-repellent surface is formed by combining a film made of diamond-like carbon and fluorine-containing diamond-like carbon on the surface. Item 3. The screen printing apparatus according to Item 1 or 2.   The screen printing apparatus according to claim 1, wherein a surface of the squeegee has higher water repellency than a material inside the squeegee. The sample to be screen printed is brought into close contact with the mask for screen printing,
Supply the paste to the mask with the sample adhered,
While moving the squeegee against the mask supplied with the paste in one direction,
A screen printing method in which a pattern formed on the screen is formed on the sample by peeling the sample from the mask in a state where the movement of the squeegee in one direction is completed,
The squeegee is a liquid-repellent film that repels the paste on the front side of the squeegee when the squeegee is pressed against the mask with respect to the moving direction than the position where the squeegee contacts the mask. The coated recess is formed so that the end of the recess opposite to the side in contact with the mask protrudes toward the mask and opens a gap with the mask, while pressing the squeegee against the mask A screen printing method characterized in that printing is performed while accumulating paste in a space formed by a recess formed on a surface of which is coated with a liquid repellent film and the mask when moved in one direction.   By moving the squeegee in one direction while pressing the squeegee against the mask, paste accumulated in the space formed by the recess formed by the liquid repellent film on the surface of the squeegee and the mask. 13. The screen printing method according to claim 12, wherein printing is performed while rolling along a liquid-repellent film covering the surface of the concave portion in the space to be formed.   The screen printing method according to claim 12, wherein a mask formed of a metal plate is used as the mask.   The screen printing method according to claim 12, wherein a mask formed of a metal mesh is used as the mask.

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