JP7634607B2 - Screen printing mask - Google Patents

Description

The present invention relates to a screen printing mask used when forming fine print patterns such as internal electrodes of ceramic capacitors and multilayer chip inductors by screen printing.

This type of screen printing mask is disclosed, for example, in Patent Document 1, which was previously proposed by the present applicant. The screen printing metal mask (mask) described in Patent Document 1 includes a mask plate (lower layer) having a group of pattern openings and cut mark openings, and a squeegee plate (upper layer) having a group of adjustment openings corresponding to the pattern openings and cut mark openings. The squeegee plate and mask plate are each made of metal, and the upper surface of the squeegee plate serves as the squeegee surface with which the squeegee comes into contact.

JP 2015-127126 A

During printing, the squeegee moves in one direction with the tip of the squeegee pressed against the squeegee surface. During the movement of the squeegee, a tensile stress acts on the mask upstream of the contact position of the tip of the squeegee in the direction of the squeegee movement, while a compressive stress acts on the mask downstream of the contact position of the tip of the squeegee. In the mask of Patent Document 1, the squeegee surface, i.e., the upper surface of the squeegee plate, is a flat plate surface except for a group of adjustment openings and cut mark openings. Therefore, the tip of the squeegee, which makes line contact with the squeegee surface, is in contact with the squeegee surface in most of its length direction, and the sliding resistance due to friction between the squeegee surface and the tip of the squeegee generated during the movement of the squeegee is large. If the sliding resistance of the squeegee is large, the tensile stress and compressive stress acting on the mask also become large accordingly, and if the mask expands and contracts due to the stress and the pattern openings are deformed, a printing pattern of an appropriate shape cannot be obtained. In addition, the durability of the mask may decrease due to metal fatigue caused by repeated expansion and contraction.

The present invention suppresses the expansion and contraction of the mask caused by the tensile stress and compressive stress generated in the mask due to the sliding resistance of the squeegee, thereby enabling the printing pattern to be formed on the printing object with high accuracy,
Another object is to improve the durability of the mask.

The screen printing mask of the present invention comprises a lower layer 2 having a group of pattern openings 3, and an upper layer 1 having a group of adjustment openings 4 corresponding to the pattern openings 3. The upper surface of the upper layer 1 serves as a squeegee surface 6 against which a squeegee S slides. The squeegee surface 6 is characterized in that it is provided with a friction-reducing portion 13 formed as a recess.

The friction reducing portion 13 is configured as a surface-reducing recess 15 recessed into the squeegee surface 6 so as to coincide with the position where the adjustment opening 4 is formed.

The friction reducing portion 13 is composed of a surface reduction groove 17 recessed into the squeegee surface 6 to avoid the position where the adjustment opening 4 is formed.

The upper layer 1 is made of metal, and the lower layer 2 is made of resin.

The upper layer 1 and the lower layer 2 are integrally formed with one metal layer 40.

When the squeegee surface 6 is provided with the friction reducing portion 13 formed by recesses as in the screen printing mask according to the present invention, the upper surface of the upper layer 1 constituting the squeegee surface 6 is made into an uneven surface,
The length (area) of the tip of the squeegee S that contacts the squeegee surface 6 can be reduced by the amount of the friction reducing section 13. As a result, compared to conventional masks in which most of the squeegee tip is in contact with the squeegee surface, friction between the tip of the squeegee S and the squeegee surface 6 can be reduced, reducing sliding resistance, thereby suppressing the tensile stress and compressive stress that occur in the mask when the squeegee S moves, and allowing the printing pattern to be formed with higher accuracy on the printing object.
The durability of the mask can also be improved.

When the friction reducing portion 13 is configured with a surface-reducing recess 15 recessed into the squeegee surface 6 so as to coincide with the formation position of the adjustment opening 4, the friction reducing effect can be achieved with a simple configuration of simply recessing the surface-reducing recess 15 into the squeegee surface 6 of the upper layer 1. Furthermore, compared to conventional masks, the mask can be made lighter by the amount of the surface-reducing recess 15, and the material for forming the upper layer 1 can be reduced by the amount of the surface-reducing recess 15, thereby reducing the manufacturing cost of the mask.

When the friction reducing portion 13 is configured with a surface-reducing groove 17 recessed into the squeegee surface 6 to avoid the formation position of the adjustment opening 4, a friction reducing effect can be achieved with a simple configuration of simply recessing the surface-reducing groove 17 into the squeegee surface 6 of the upper layer 1. Furthermore, compared to conventional masks, the mask can be made lighter by the amount of the surface-reducing groove 17, and the material for forming the upper layer 1 can be reduced by the amount of the surface-reducing groove 17, thereby reducing the manufacturing cost of the mask.

When the upper layer 1 is made of metal and the lower layer 2 is made of resin, the weight of the lower layer 2 can be reduced compared to conventional masks in which the squeegee plate (upper layer) and the mask plate (lower layer) are both made of metal, so that the weight of the mask can be reduced. This makes it possible to prevent the center of the mask from curving downward due to its own weight when it is attached to the mask support of the screen printing device, so that deformation of a group of pattern openings 3 due to the curvature of the mask can be prevented, thereby improving the accuracy of printing. In addition, in a screen printing device in which printing is performed by moving a mask over a fixed printing target, the load on the device can be reduced by the amount of inertia associated with the mask movement, which can contribute to improving the accuracy of positioning and shortening the printing cycle.

When the upper layer 1 and the lower layer 2 are integrally formed as one metal layer 40, peeling between the layers 1 and 2 and damage to the mask can be prevented, compared to when the upper layer 1 and the lower layer 2 are formed as two layers, such as metal and metal or metal and resin.

1 is a vertical sectional side view of a screen printing mask according to a first embodiment of the present invention. 1A and 1B are an overall plan view of a screen printing mask according to a first embodiment and an enlarged view of a pattern opening and an adjustment opening. 4A to 4C are explanatory diagrams showing a primary electroforming step in the method for producing a screen printing mask according to the first embodiment. 5A to 5C are explanatory diagrams showing a secondary electroforming step in the method for producing a screen printing mask according to the first embodiment. 5A to 5C are explanatory views showing a resin layer forming step in the method for manufacturing the screen printing mask according to the first embodiment. FIG. 11 is a vertical sectional side view of a screen printing mask according to a second embodiment of the present invention. 10A to 10C are explanatory diagrams showing a primary electroforming step in a method for producing a screen printing mask according to Example 2. 10A to 10C are explanatory diagrams showing a secondary electroforming step in the method for producing a screen printing mask according to Example 2. 10A to 10C are explanatory views showing a resin layer forming step in the method for producing a screen printing mask according to Example 2. FIG. 11 is a vertical sectional side view of a screen printing mask according to a third embodiment of the present invention. 13A to 13C are explanatory views showing a dummy forming step in the method for manufacturing a screen printing mask according to Example 3. 13A to 13C are explanatory views showing a mask forming step in the method for manufacturing a screen printing mask according to Example 3.

1 to 5 show a screen printing mask (hereinafter, simply referred to as a printing mask) according to a first embodiment of the present invention.
Also, follow the crossed arrows shown in FIG. 2 and the indications of front, back, left, right, up and down written near each arrow.
The dimensions such as thickness and width in each drawing of the following examples do not represent the actual state.
Each is shown diagrammatically.

The printing mask is used to print and form the internal electrodes that constitute the multilayer ceramic capacitor on the surface of the ceramic film to be printed by a screen printing method. In FIG. 2, the printing mask is formed in a square shape with one side of 250 mm. When the mask is divided into four quadrants, each quadrant has a pattern formation region M for printing an electrode pattern.
is defined, and further, a cut mark forming region C for printing cut marks that are used when cutting the printing target into a specified shape in a process after screen printing is defined so as to surround the periphery of the pattern forming region M. The printing mask is attached to the mask fixing section of the screen printing device either by itself or with a frame fixed to its four peripheral edges.

As shown in Fig. 1, the printing mask has a two-layer structure in which an upper layer 1 made of metal and a lower layer 2 made of synthetic resin (resin) are laminated together, the lower layer 2 is provided with a group of pattern openings 3, and the upper layer 2 is provided with a group of adjustment openings 4 corresponding to the pattern openings 3.
The outer shape of the adjustment opening 4 can be formed to be the same as the opening shape of the pattern opening 3 or to be slightly smaller than the opening shape of the pattern opening 3 .

2, the pattern openings 3 formed in the lower layer 2 are formed in a rectangular shape that is long from side to side, and are arranged in a matrix in the pattern formation region M. The adjustment openings 4 formed in the upper layer 1 above the pattern openings 3 are formed in a mesh-like shape with a lattice-like adjustment rib 5 formed therein, and the outer shape of the adjustment openings 4 is formed slightly larger than the opening shape of the pattern openings 3. The adjustment rib 5 is provided to adjust the amount of printing paste supplied to the pattern openings 3.

Although not shown, in the cut mark formation region C, a cut mark opening formed in a long and narrow rectangular shape is formed in the lower layer 2, and an adjustment opening for the cut mark opening is formed in the upper layer 1 above the cut mark opening. The adjustment opening has a lattice-shaped adjustment rib formed therein to form a mesh-shaped opening, and its outer shape is formed to be slightly larger than the opening shape of the cut mark opening. The outer shape of the adjustment opening for the cut mark opening can be formed to be the same as the opening shape of the cut mark opening or slightly smaller than the opening shape of the cut mark opening. The opening shapes of the pattern formation region M and the cut mark formation region C may be made different.

The upper surface of the upper layer 1 constitutes the squeegee surface 6, and during printing, the printing paste placed on the squeegee surface 6 is squeegeeed by the squeegee S, filling the pattern openings 3 and the cut mark openings with the printing paste, forming a printing layer on the surface to be printed, which consists of an electrode pattern that matches the pattern openings 3 and a cut pattern that matches the cut mark openings. The squeegee S forms a printing layer while moving from the front side to the rear side of the printing mask with its tip in contact with the squeegee surface 6. The "printing paste" referred to here is a concept that includes solder paste, cream solder, liquid solder, conductive ink, etc. The squeegee S in FIG. 1 is also shown in a schematic reduced state, as are the dimensions such as thickness and width.

The upper layer 1 of this embodiment is formed by laminating an upper first metal layer 11 having a relatively small thickness and a lower second metal layer 12 having a relatively large thickness, and a friction reducing portion 13 that reduces sliding friction between the squeegee S and the squeegee surface 6 is recessed and formed on the squeegee surface 6. The adjustment opening 4 is formed in the second metal layer 12, and a through hole 14 is formed in the first metal layer 11 corresponding to the adjustment opening 4. The through hole 14 is formed in a shape that is slightly larger than the outer shape of the adjustment opening 4, and a surface-reducing recess 15 is formed on the squeegee surface 6 by the through hole 14 and the upper surface of the second metal layer 12. The adjustment opening 4 is opened on the bottom surface of the surface-reducing recess 15.

By providing the surface-reducing recesses 15 corresponding to the adjustment openings 4, the area of the squeegee surface 6 is reduced by the amount of the surface-reducing recesses 15, and the recesses 15 constitute friction reducing sections 13 that reduce friction between the squeegee S and the squeegee surface 6. Due to the surface-reducing recesses 15 formed in each adjustment opening 4, the squeegee surface 6 in the pattern forming region M is shaped like a lattice frame. The printing paste enters the adjustment openings 4 through the surface-reducing recesses 15 and fills the pattern openings 3. First metal layer 11
The thickness of the first metal layer 12 is set to 2 μm, the thickness of the second metal layer 13 is set to 16 μm, and the thickness of the upper layer 1 made of metal is 18 μm. The thickness of the lower layer 2 made of resin is set to 3 μm, and the total thickness of the printing mask is formed to 21 μm. It is also possible to provide a surface-reducing recess 15 corresponding to the adjustment opening for the cut mark opening.

As described above, the friction reducing portion 13 is configured as the surface-reducing recess 15 recessed into the squeegee surface 6 so as to coincide with the position where the adjustment opening 4 is formed.
The friction reduction effect can be achieved by a simple structure in which the mask is recessed.
Since the material for forming the upper layer 1 can be reduced by the amount of the mask 5, the manufacturing cost of the mask can be reduced.

An example of a method for manufacturing the printing mask according to the present embodiment is shown in FIG.
The primary electroforming process shown in (a) to (d), the secondary electroforming process shown in FIG. 4(a) to (d), and the secondary electroforming process shown in FIG.
In the primary electroforming step, as shown in FIG. 3(a), a conductive plate-shaped electroforming matrix 20 made of stainless steel is coated on the surface thereof with a resin layer.
A negative type first photoresist layer 21 is formed. Next, a first pattern film 22 (photomask) is adhered to the first photoresist layer 21, thereby obtaining the laminate shown in FIG.

Next, the inside of the furnace of the ultraviolet irradiation device equipped with the ultraviolet lamp 23 is preheated to the furnace temperature during the exposure operation. After the preheating is completed, the laminate obtained above is placed in the furnace of the ultraviolet irradiation device, and the laminate is allowed to acclimate to the furnace temperature, and then irradiated with ultraviolet light by the ultraviolet lamp 23.
The first photoresist layer 21 is exposed through the first pattern film 22. The exposed laminate is taken out, the first pattern film 22 is removed from the first photoresist layer 21, and the unexposed portions of the first photoresist layer 21 are dissolved and removed (developed) to form a primary pattern resist 24 on the electroforming matrix 20, as shown in Fig. 3(b). The primary pattern resist 24 is composed of resist bodies corresponding to the openings of the adjustment openings 4 for the pattern openings 3 and the adjustment openings for the cut mark openings.

3C, the surface of the electroforming matrix 20 that is not covered with the primary pattern resist 24 is subjected to electroforming (plating) processing to form a primary electroforming layer 25 that will become the second metal layer 12 within the range of the height of the primary pattern resist 24. After the primary electroforming layer 25 is formed,
When the surfaces of the primary pattern resist 24 and the primary electroforming layer 25 are polished and smoothed, the result is as shown in FIG.
The result is state d).

In the secondary electroforming process, as shown in FIG. 4(a), a negative type second photoresist layer 28 is formed on the surfaces of the primary pattern resist 24 and the primary electroforming layer 25. Next, a second pattern film 29 (photomask) is adhered to the second photoresist layer 28. The second pattern film 29 has light-transmitting holes corresponding to the through holes 14. Next, ultraviolet light is irradiated from an ultraviolet lamp 23 to expose the second photoresist layer 28 through the second pattern film 29. After exposure, the second pattern film 29 is removed from the second photoresist layer 28, and the unexposed portions of the second photoresist layer 28 are dissolved and removed (developed), thereby leaving the primary pattern resist 24 and the primary electroforming layer 25 as shown in FIG. 4(b).
A secondary pattern resist 30 is formed on the through hole 14.
The resist layer is made of a material corresponding to the resist pattern.

Next, as shown in Fig. 4(c), electroforming (plating) is performed on the surface of the primary electroforming layer 25 that is not covered with the secondary pattern resist 30 to form a secondary electroforming layer 31 that will become the first metal layer 11 within the height range of the secondary pattern resist 30. After the secondary electroforming layer 31 is formed, the electroforming matrix 20 is removed to obtain the mask precursor body shown in Fig. 4(d). Note that, before removing the electroforming matrix 20, the surfaces of the secondary pattern resist 30 and the secondary electroforming layer 31 may be polished to be smooth. Note that polishing in each process can be performed as necessary.

In the resin layer forming process, the inverted mask precursor body is temporarily fixed on a surface plate, as shown in FIG.
As shown in FIG. 5B, a photocurable emulsion resin (photocurable resin) 34 is poured onto the surface of the mask precursor, and the emulsion resin 34 is uniformly applied to the surfaces of the primary electroforming layer 25 and the primary pattern resist 24 by utilizing the fluidity derived from the emulsion. After the emulsion resin 34 is uniformly applied, a third pattern film 35 (photomask) is placed on the emulsion resin 34. The third pattern film 35 can be placed in close contact with the emulsion resin 34, or can be placed directly opposite the surface of the emulsion resin 34 with a small gap therebetween. Next, the emulsion resin 34 is exposed to ultraviolet light through the third pattern film 35 by irradiating it with ultraviolet light from the ultraviolet lamp 23, and hardened. After hardening, the third pattern film 29 is removed from the emulsion resin 34, and the unhardened portion of the emulsion resin 34 is removed, thereby forming a lower layer 2 on the mask precursor having openings corresponding to the pattern openings 3 on the primary pattern resist 24 and the primary electroforming layer 25, as shown in FIG. 5B. Finally, the primary and secondary pattern resists 24 and 30 are removed and inverted again to obtain the completed printing mask shown in FIG. 5(c).

Since the lower layer 2 in this embodiment is made of a photocurable resin, it is possible to form the lower layer 2 by a photolithography method.
The lower layer 2 can be formed easily and with high precision, with a complex planar shape. Furthermore, the photocurable resin constituting the lower layer 2 is formed from a photocurable emulsion resin 34, and therefore can be easily applied so that the surface of the emulsion resin 34 becomes smooth due to the fluidity derived from the emulsion. The photocurable emulsion resin 34 may be one that hardens in response to visible light, as well as one that hardens in response to ultraviolet light. The lower layer 2 is not limited to the photocurable emulsion resin 34 used in this embodiment,
It can also be formed of a liquid resist body or a sheet-like resist body. The lower layer 2 can also be composed of a thermosetting resin. Thermosetting resins have better chemical resistance and solvent resistance than photocurable resins, so they can be used suitably even in printing environments where printing pastes containing acids, alkalis, solvents, etc. are used. They are also excellent in that they can be used with cleaning agents containing acids, alkalis, solvents, etc. to clean the mask after use.

In the above description, the surface-reducing recess 15 is formed on the squeegee surface 6. However, when the surface on which the adjustment opening 4 is formed is taken as the reference surface, it can also be considered that the first metal layer 11 forms a lattice frame-shaped protrusion that protrudes upward from the reference surface, i.e., the upper surface of the second metal layer 12, between adjacent adjustment openings 4. In this case, the upper surface of the lattice frame-shaped protrusion formed on the first metal layer 11 is in contact with the squeegee surface 6.
The protrusion can be formed in a frame shape so as to surround the pattern formation region M and/or the cut mark formation region C. In addition, the protrusion is not limited to a lattice frame shape and a continuous shape, and may be discontinuous (dotted line shape).

(Example 2) Figures 6 to 9 show Example 2 of the screen printing mask (hereinafter simply referred to as the printing mask) according to the present invention. In this example, the configuration of the friction reducing portion 13 is different from that of Example 1. Specifically, the upper layer 1 is formed by laminating the upper first metal layer 11 and the lower second metal layer 12, and the friction reducing portion 13 that reduces the sliding friction between the squeegee S and the squeegee surface 6 is recessed and formed on the squeegee surface 6. A slit 16 is formed in the first metal layer 11 between adjacent adjustment openings 4, and a surface reduction groove 17 is formed on the squeegee surface 6 by the slit 16 and the upper surface of the second metal layer 12. The surface reduction groove 17 is formed so as to avoid the adjustment opening 4, and the adjustment opening 4 is opened on the squeegee surface 6 adjacent to the surface reduction groove 17.

The area of the squeegee surface 6 is reduced by the area of the surface-reducing grooves 17, and the grooves 17 constitute friction reducing portions 13 that reduce friction between the squeegee S and the squeegee surface 6. Due to the surface-reducing grooves 17 formed in a lattice frame shape so as to avoid each adjustment opening 4, the squeegee surface 6 in the pattern forming region M is
The squeegee surface 6, which is a rectangular frame surrounding the adjustment opening 4, is arranged in a matrix. The thickness of the first metal layer 11 is set to 2 μm, the thickness of the second metal layer 12 is set to 16 μm, and the thickness of the upper layer 1 made of a metal layer is 18 μm. The thickness of the lower layer made of a resin layer is 3.
The thickness of the printing mask is set to 21 μm, and the total thickness of the printing mask is set to 21 μm. It is also possible to provide a surface-reducing recess 15 corresponding to the adjustment opening for the cut mark opening. Since the rest is the same as in Example 1, the same members are given the same reference numerals and the description thereof is omitted. The same applies to the following examples.

As described above, the friction reducing portion 13 is configured by the surface reduction groove 17 recessed into the squeegee surface 6 avoiding the position where the adjustment opening 4 is formed, so that the friction reducing effect can be achieved with a simple structure of only recessing the surface reduction groove 17 into the squeegee surface 6 of the upper layer 1. Compared to conventional masks,
The weight of the mask can be reduced by the area of the surface-reducing groove 17.
Since the amount of material required for forming the mask can be reduced, the manufacturing cost of the mask can be reduced.

An example of a method for manufacturing the printing mask according to this embodiment is shown in FIGS.
The primary electroforming process shown in (a) to (d), the secondary electroforming process shown in (a) to (d) of FIG. 8, and the secondary electroforming process shown in FIG.
In the primary electroforming step, as shown in FIG. 7(a), a conductive plate-shaped electroforming matrix 20 made of stainless steel is coated on the surface thereof with a resin layer.
A negative type first photoresist layer 21 is formed. Next, a first pattern film 22 (photomask) is adhered to the first photoresist layer 21, thereby obtaining the laminate shown in FIG.

Next, the inside of the furnace of the ultraviolet irradiation device equipped with the ultraviolet lamp 23 is preheated to the furnace temperature during the exposure operation. After the preheating is completed, the laminate obtained above is placed in the furnace of the ultraviolet irradiation device, and the laminate is allowed to acclimate to the furnace temperature, and then irradiated with ultraviolet light by the ultraviolet lamp 23.
The first photoresist layer 21 is exposed through the first pattern film 22. The exposed laminate is taken out, the first pattern film 22 is removed from the first photoresist layer 21, and the unexposed portions of the first photoresist layer 21 are dissolved and removed (developed) to form a primary pattern resist 24 on the electroforming matrix 20, as shown in Fig. 7(b). The primary pattern resist 24 is composed of resist bodies corresponding to the openings of the adjustment openings 4 for the pattern openings 3 and the adjustment openings for the cut mark openings.

7C, the surface of the electroforming matrix 20 that is not covered with the primary pattern resist 24 is subjected to electroforming (plating) processing to form a primary electroforming layer 25 that will become the second metal layer 12 within the range of the height of the primary pattern resist 24. After the primary electroforming layer 25 is formed,
The surfaces of the primary pattern resist 24 and the primary electroforming layer 25 are polished and smoothed, as shown in FIG.
The result is state d).

In the secondary electroforming process, as shown in FIG. 8(a), a negative type second photoresist layer 28 is formed on the surface of the primary pattern resist 24 and the primary electroforming layer 25. Next, a second pattern film 29 (photomask) is attached to the second photoresist layer 28. The second pattern film 29 has light-transmitting holes corresponding to the openings of the adjusted openings 4 for the pattern openings 3 and the adjusted openings for the cut mark openings and the slits 16. Next, the second photoresist layer 28 is exposed to ultraviolet light through the second pattern film 29 by irradiating the second photoresist layer 28 with ultraviolet light from the ultraviolet lamp 23. After exposure, the second pattern film 29 is removed from the second photoresist layer 28, and the unexposed parts of the second photoresist layer 28 are dissolved and removed (developed) to form a secondary pattern resist 30 on the primary pattern resist 24 and the primary electroforming layer 25, as shown in FIG. 8(b). The secondary pattern resist 30 has a resist body 3 corresponding to the openings of the adjusted openings 4 for the pattern openings 3 and the adjusted openings for the cut mark openings.
1 and a resist body 30a corresponding to the slit 16.

Next, as shown in Fig. 8(c), an electroforming (plating) process is performed on the surface of the primary electroforming layer 25 that is not covered with the secondary pattern resist 30, thereby forming a secondary electroforming layer 31 that will become the first metal layer 11 within the height range of the secondary pattern resist 30. After the secondary electroforming layer 31 is formed, the electroforming matrix 20 is removed to obtain the mask precursor body shown in Fig. 8(d). Note that, before removing the electroforming matrix 20, the surfaces of the secondary pattern resist 30 and the secondary electroforming layer 31 may be polished and smoothed.

In the resin layer forming process, the inverted mask precursor body is temporarily fixed on a surface plate, as shown in FIG.
As shown in FIG. 9(b), a photocurable emulsion resin (photocurable resin) 34 is poured onto the surface of the mask precursor, and the emulsion resin 34 is uniformly applied to the surfaces of the primary electroforming layer 25 and the primary pattern resist 24 by utilizing the fluidity derived from the emulsion. After the emulsion resin 34 is uniformly applied, a third pattern film 35 (photomask) is placed on the emulsion resin 34. The third pattern film 35 can be placed in close contact with the emulsion resin 34, or can be placed directly opposite the surface of the emulsion resin 34 with a small gap therebetween. Next, the emulsion resin 34 is exposed to ultraviolet light through the third pattern film 35 by irradiating it with ultraviolet light from the ultraviolet lamp 23, and hardened. After hardening, the third pattern film 29 is removed from the emulsion resin 34, and the unhardened portion of the emulsion resin 34 is removed, thereby forming a lower layer 2 on the mask precursor having openings corresponding to the pattern openings 3 on the primary pattern resist 24 and the primary electroforming layer 25, as shown in FIG. 9(b). Finally, the primary and secondary pattern resists 24 and 30 are removed to obtain the completed printing mask shown in FIG. 9(c).

When the lower layer 2 is made of a resin layer as in the above-mentioned embodiments, the emulsion resin 34 can be applied thinly and uniformly by utilizing the fluidity derived from the emulsion resin 34. Therefore, the lower layer 2 made of a resin layer can be formed thin and uniformly, improving the printing accuracy of the mask and enabling the mask to be made thinner and lighter overall.
Since the coating can be carried out by utilizing the fluidity derived from the above, it has the advantage that a thin and uniform thickness of the lower layer can be easily formed.

In the above-mentioned embodiments, the lower layer 2 is formed from a photocurable emulsion resin 34, but the lower layer 2 can also be formed by adhering a resin sheet to the lower surface of the upper layer 1. In this case, the resin sheet before adhering is subjected to laser processing to cut out the pattern opening 3, and then the resin sheet is adhered to the upper layer 1. Alternatively, a printing mask can be obtained by adhering a resin sheet to the upper layer 1, and then performing laser processing to remove the pattern opening 3 by sublimation. The resin layer forming process can also be the following method. A plate-shaped thermoplastic resin plate heated to a softening temperature or higher is placed on the surface of a mask front stage body temporarily fixed on a surface plate, and the softened thermoplastic resin plate is pressed flat against the mask front stage body. This results in a state in which a part of the resin plate has entered the receiving recess 16A. The thermoplastic resin plate is cooled and hardened again, and then unnecessary parts of the thermoplastic resin plate are sublimated and removed by laser processing, or melted and removed by etching to form the pattern opening 3, thereby forming the lower layer 2.

Since the upper layer 1 is made of metal and the lower layer 2 is made of synthetic resin, the weight of the lower layer 2 can be reduced compared to conventional masks in which the squeegee plate (upper layer) and the mask plate (lower layer) are both made of metal.
The weight of the mask can be reduced. This makes it possible to prevent the center of the mask from curving downwardly due to its own weight when it is attached to the mask support of the screen printing device, thereby preventing deformation of the group of pattern openings 3 due to the curvature of the mask and improving printing accuracy. Furthermore, in a screen printing device that performs printing by moving the mask over a fixed printing target, the load on the device can be reduced by the amount of inertia associated with the mask movement, which contributes to improving positioning accuracy and shortening the printing cycle.

In the manufacturing method in each of the above-mentioned embodiments, the resin layer forming step was performed while leaving the primary pattern resist 24 and the secondary pattern resist 30.
It is also possible to perform the resin layer forming step after removing the primary pattern resist 24 and the secondary pattern resist 30. In this case, it is possible to prevent the lower layer 2 (photocurable resin 34) from falling off and being removed together when removing the primary pattern resist 24 and the secondary pattern resist 30. The printing mask of each of the above-mentioned embodiments can also be obtained by using an electroforming mold in which a recess corresponding to the first metal layer 11 is formed, forming a primary electroforming layer that becomes the first metal layer 11 in the recess in the primary electroforming step, forming a secondary electroforming layer that becomes the second metal layer 12, and then forming the lower layer 2 with the photocurable resin 34 in the resin layer forming step. In this case, the electroforming mold may be removed after the resin layer forming step (formation of the lower layer 2).

10 to 12 show Example 3 of a screen printing mask (hereinafter simply referred to as a printing mask) according to the present invention. The printing mask of this example differs from Example 2 in that the upper layer 1 and the lower layer 2 are formed from a single mask metal layer (metal layer) 40. In the mask metal layer 40, the thickness portion that forms the group of adjustment openings 4 constitutes the upper layer 1, and the thickness portion that forms the remaining group of pattern openings 3 constitutes the lower layer 2. A surface-reducing groove 17 that constitutes a friction-reducing portion 13 is formed on the squeegee surface 6 so as to avoid the adjustment openings 4.

An example of a method for manufacturing a printing mask according to this embodiment is shown in Figures 11 and 12. The printing mask is formed through a dummy formation process shown in Figures 11(a) to (d) and a mask formation process shown in Figures 12(a) to (d). In the dummy formation process, as shown in Figure 11(a), a negative type photoresist layer 43 is formed on the surface of a flat plate-shaped electroforming mold 42 made of stainless steel and having electrical conductivity. Next, a pattern film 44 (photomask) is brought into close contact with the photoresist layer 43, thereby obtaining the laminate shown in Figure 11(a).

Next, the inside of the furnace of the ultraviolet irradiation device equipped with the ultraviolet lamp 45 is preheated to the furnace temperature during the exposure operation. After the preheating is completed, the laminate obtained above is placed in the furnace of the ultraviolet irradiation device, and the laminate is allowed to acclimate to the furnace temperature, and then irradiated with ultraviolet light by the ultraviolet lamp 45.
The photoresist layer 43 is exposed through the pattern film 44. The laminate after exposure is taken out, the pattern film 44 is removed from the photoresist layer 43, and the photoresist layer 4
11B, the unexposed portions of the resist pattern 3 are dissolved and removed (developed) to form a pattern resist 46 on the electroforming matrix 42. The pattern resist 46 is made up of a resist body that corresponds to the area-reducing grooves 17.

11(c), electroforming (plating) is performed on the surface of the electroforming mold 42 that is not covered with the pattern resist 46, thereby forming a dummy electroforming layer 47 within the range of the height of the pattern resist 46. After the dummy electroforming layer 47 is formed, the surfaces of the pattern resist 46 and the dummy electroforming layer 47 are polished and smoothed, and the pattern resist 46 is then removed, resulting in the state shown in FIG.

In the mask forming step, as shown in Fig. 12(a), a negative type mask photoresist layer 49 is formed on the surfaces of the electroforming matrix 42 and the dummy electroforming layer 47. Next, a mask pattern film 50 (photomask) is adhered to the mask photoresist layer 49. The mask pattern film 50 has light transmitting holes formed therein that correspond to the openings of the adjustment openings 4 for the pattern openings 3 and the adjustment openings for the cut mark openings. Next, an ultraviolet lamp 4 is turned on to emit light.
5, the mask photoresist layer 49 is exposed through the mask pattern film 50 by irradiation with ultraviolet light. After exposure, the mask photoresist layer 49 is removed from the mask pattern film 50.
12B, the mask photoresist layer 49 is removed, and the unexposed portions of the mask photoresist layer 49 are dissolved and removed (developed), thereby forming a mask pattern resist 51 on the electroforming matrix 42. The mask pattern resist 51 is composed of a resist body corresponding to the openings of the adjustment openings 4 for the pattern openings 3 and the adjustment openings for the cut mark openings.

12C, the surfaces of the electroforming matrix 42 and the dummy electroforming layer 47 that are not covered with the mask pattern resist 51 are subjected to electroforming (plating) processing to form a mask electroforming layer 52 that will become the mask metal layer 40 within the range of the height of the mask pattern resist 51. At this time, since the electroforming thickness in the electroforming processing is constant, the dummy electroforming layer 47 is formed.
The portion protrudes upward beyond the portion of the electroforming matrix 42. In this way, the lower layer 2 in which the pattern openings 3 are provided is formed integrally with the upper layer 1. After the formation of the mask electroforming layer 52, the mask pattern resist 51 is removed, and then the electroforming matrix 42 and the dummy electroforming layer 47 are removed, to obtain the finished printing mask shown in FIG.

According to this embodiment, the upper layer 1 and the lower layer 2 are formed by one mask metal layer 40. Therefore, the upper layer 1 and the lower layer 2 are formed by two layers such as metal and metal or metal and resin.
The risk of peeling between the electroforming mold 42 and the printing mask being damaged can be avoided. In addition, compared to the printing masks of Examples 1 and 2, the manufacturing cost of the printing mask can be reduced by the amount that can be manufactured by omitting the resin layer formation process.
By forming the dummy electroforming layer 47 firmly integrated with the lower layer 2 so as to be inseparable, the mask forming process can be started from this, and the manufacturing of the printing mask can be simplified by omitting the dummy forming process, and the printing mask can be manufactured more inexpensively. In order to strengthen the adhesion between the electroforming mold 42 and the dummy electroforming layer 47, it is preferable to perform an adhesion treatment (pre-plating treatment) before forming the dummy electroforming layer 47. In addition, in order to improve the peelability between the dummy electroforming layer 47 and the metal layer 40, it is preferable to perform a peeling treatment on at least the surface of the dummy electroforming layer 47. It is also possible to consider a printing mask in which the dummy electroforming layer 47 and the metal layer 40 are integrated without separating them. In addition, the printing mask of this embodiment uses an electroforming mold in which a recess corresponding to the lower layer 2 is formed, and after forming the mask pattern resist 51, the mask metal layer 4
Alternatively, the mask electroforming layer 52 may be formed to have a zero thickness.

As described above, in the screen printing mask according to each of the above-mentioned embodiments, the squeegee surface 6 is provided with the friction reducing portion 13 formed by a downward recess, so that the upper surface of the upper layer 1 constituting the squeegee surface 6 can be made uneven, and the length of the tip of the squeegee S contacting the squeegee surface 6 can be reduced by the friction reducing portion 13. As a result, compared to conventional masks in which most of the squeegee tip is in contact with the squeegee surface, the friction between the tip of the squeegee S and the squeegee surface 6 can be reduced, thereby reducing the sliding resistance, so that the tensile stress and compressive stress generated in the mask when the squeegee S moves can be suppressed, and the printing pattern can be formed on the printing target with higher accuracy. In addition, the durability of the mask can be improved.

In the above embodiments, the surface-reducing recess 15 and the surface-reducing groove 17 are formed as recesses and grooves without steps, but they can be formed as multi-step recesses and grooves. The dimensions of each part are not limited to those shown in the above embodiments. The printing mask of the present invention is not limited to those used for printing and forming the internal electrodes that constitute the multilayer ceramic capacitor. In addition, the mask structure of the printing mask can be used as a vapor deposition mask, a solder ball mounting mask, and a solder ball suction mask.

1 Upper layer 2 Lower layer 3 Pattern opening 4 Adjustment opening 6 Squeegee surface 13 Friction reduction portion 15 Surface reduction recess 17 Surface reduction groove 40 Metal layer (mask metal layer)
S squeegee

Claims (5)

A lower layer (2) having a group of pattern openings (3) and an upper layer (1) having a group of adjustment openings (4) corresponding to the pattern openings (3),
The upper surface of the upper layer (1) is a squeegee surface (6) on which the squeegee (S) slides.
A friction reducing portion (13) formed by a recess is provided on the squeegee surface (6),
A screen printing mask characterized in that the thickness of the lower layer (2) is constant with the depth of the recesses in the friction reducing portions (13) formed as recesses . The screen printing mask according to claim 1, wherein the friction reducing portion (13) is composed of a surface reduction recess (15) recessed into the squeegee surface (6) so as to coincide with the position where the adjustment opening (4) is formed. The screen printing mask according to claim 1, wherein the friction reducing portion (13) is composed of a surface reduction groove (17) recessed into the squeegee surface (6) to avoid the position where the adjustment opening (4) is formed. A screen printing mask according to any one of claims 1 to 3, in which the upper layer (1) is made of metal and the lower layer (2) is made of resin. A screen printing mask according to claim 1 or 3, in which the upper layer (1) and the lower layer (2) are integrally formed with a single metal layer (40).