TW202322231A - metal mask for printing - Google Patents

Abstract

The invention provides a metal mask for printing, which can further improve the printing precision when forming a printing layer, and can form a high-precision and high-quality printing layer. This metal mask for printing is provided with: a mask body (7) having a rear surface (9) facing a printing target (2); and a plurality of through holes (10) which penetrate the mask main body (7) on the front and back and are filled with the printing paste (4). The through hole (10) is configured from a first hole section (13) that opens in the front surface (8) of the mask main body (7), and a second hole section (14) that is continuous with the first hole section (13) and opens in the back surface (9) of the mask main body (7). Either the first hole portion (13) or the second hole portion (14) is composed of a linear hole, and the cross-sectional shape of the inner surface of the other is formed in an R shape.

Description

metal mask for printing

The present invention relates to a technology for improving printing defects such as penetration and fading of a printing layer for a metal mask. As the metal mask of the present invention, for example, a metal mask for printing used when printing and forming a layer of flux (printing paste) for temporarily fixing solder balls on a substrate by a screen printing method .

The applicant of this application has already proposed Patent Document 1 as a technique for improving the printing accuracy of a metal mask for printing. In Patent Document 1, the cross-sectional shape of the through-hole formed in the metal mask produced by the electroforming method is formed into a tapered shape in which the diameter of the hole on the side of the electroformed surface is small and the diameter of the hole on the side of the electroformed master mold is large. When printing, the electroformed surface side becomes the front side, that is, the squeegee surface side, and the electroformed master surface side becomes the back side, that is, the object to be printed (printed object) side. When forming a layer (printing layer) of ink and paste (printing paste), first, make the printed body side of the metal mask adhere to the printed body, and then place the ink and paste on the scraper of the metal mask On the surface, the ink and paste on the scraper surface are extended and filled into the inside of the through hole with the scraper. After filling the through holes with ink and paste, by separating the metal mask from the to-be-printed body, a printing layer of ink and paste corresponding to the through-holes can be printed and formed on the to-be-printed body. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-305670

[Problem to be solved by the invention]

In the metal mask of Patent Document 1, since the through hole is made into a tapered hole that expands toward the back side, the plate releasability of ink and paste is improved, so when separating the metal mask from the printed body , It can not only separate the metal mask, but also prevent part of the ink and paste from being removed, so printing defects such as bleeding and fading can be prevented. However, in the metal mask of Patent Document 1, since the ink and paste are in contact with the entire inner surface of the through hole, the ink and paste that have been filled in the through hole still adhere to the inside of the through hole. On the surface, the metal mask is separated from the object to be printed with a part of the ink or paste adhered, causing printing defects such as distortion of the printed shape or fading of the printed color. In addition, since the adhesion state of ink and paste is not uniform in each through hole, printing defects such as uneven amounts of ink and paste in each printing layer may also occur.

An object of the present invention is to provide a metal mask for printing which can further improve the printing accuracy when printing to form a printing layer, and can form a high-precision and high-quality printing layer. [Technical means to solve the problem]

The metal mask for printing of the present invention comprises: a mask body 7 made of a thin metal plate whose back 9 faces the printing object 2; The circular hole constitutes a plurality of through holes 10 . Also, the through hole 10 is opened toward the surface 8 of the mask body 7 and constitutes a first hole 13 with a straight hole; , and the second hole 14 opening toward the back surface 9 of the mask body 7 is formed.

A form in which the first hole portion 13 is formed of a straight circular hole and the second hole portion 14 is formed of a bell-shaped hole may be employed.

When the thickness T of the mask body 7 is set to 1, H1 defined by the hole depth of the first hole portion 13 is preferably set to 0.2 or more and 0.6 or less.

More desirably, when the thickness T of the mask body 7 is set to 1, H1 defined by the hole depth of the first hole portion 13 is preferably set to 0.2 or more and less than 0.5.

The following form can be adopted, that is, when the hole depth of the second hole portion 14 is defined as H2, and half of the enlarged dimension of the second hole portion 14 is defined as D3, the second hole is formed in a manner that conforms to the inequality (H2<D3). 2 holes 14.

The following form can be adopted, that is, when the opening size of the first hole portion 13 on the surface 8 of the mask body 7 is specified as D1, and the opening size of the second hole portion 14 on the back surface 9 of the mask body 7 is specified as D2 , The opening size D2 is set to be more than 1.5 times the opening size D1.

The thickness T of the mask body 7 is preferably set to be 25 μm or less.

On the inner surface of the through hole 10 and the back surface 9 of the mask body 7, a coating layer 17 for suppressing the adhesion of the printing paste 4 is formed. When the layer thickness of the coating layer 17 of the first hole 13 is specified as C1, the layer thickness of the coating layer 17 of the second hole 14 is specified as C2, and the coating layer of the back surface 9 of the mask body 7 When the layer thickness of 17 is defined as C3, the coating layer 17 is formed so as to satisfy the inequality (C1≦C2≦C3). [Invention effect]

In the metal mask for printing of the present invention, the through hole 10 that passes through the mask body 7 towards the front and back is the first hole portion 13 that is open to the surface 8 of the mask body 7 and constitutes a straight hole; and the inner surface The cross-sectional shape is R-shaped, and the first hole 13 is smoothly continuous and enlarged, and the second hole 14 opening toward the back surface 9 of the mask body 7 is formed. In this way, if the first hole portion 13 opening toward the surface 8 of the mask body 7 is configured as a straight hole, the flow direction of the printing paste 4 when filling the through hole 10 can be made the first hole extending vertically. Since the inner surface of the hole of the portion 13 is guided, the printing paste 4 can be reliably dropped in the thickness direction (vertical direction) of the mask body 7 in the through hole 10 . Also, the second hole portion 14 connected to the first hole portion 13 has an R-shaped cross-sectional shape on its inner surface, which is smoothly continuous with the first hole portion 13 and expanded to open on the back surface 9 of the mask body 7. When the printing paste 4 is guided by the hole inner surface of the first hole portion 13 and reaches the vicinity of the boundary portion of the two hole portions 13,14, the printing paste can be applied from the hole inner surface of the second hole portion 14 near the boundary portion. 4 peel off. In addition, the printing paste 4 can reach the back surface 9 of the mask main body 7 of the second hole 14 in a state where it has been peeled off from the hole inner surface of the second hole 14 . Thus, according to the metal mask for printing of the present invention, since the printing paste 4 can be peeled off from the hole inner surface of the second hole portion 14 in the vicinity of the boundary portion of the two hole portions 13 and 14, compared with the conventional metal mask, The mask can reduce the contact area between the inner surface of the through hole 10 and the printing paste 4, and when the mask is separated from the printing object 2, the amount of printing paste 4 attached to the mask and removed from the printing object 2 can be reduced. Reduce capacity. As explained above, according to the metal mask for printing of the present invention, it is possible to suppress the occurrence of printing defects such as distortion of the printed shape of the printed layer on the printed object 2, printing fading, etc., so that printing accuracy can be achieved when the printed layer is formed by printing. The improvement of the method can form a high-precision and high-quality printing layer on the printing object 2.

If the first hole 13 is made of a straight circular hole and the second hole 14 is made of a bell-shaped hole, then, compared with the first hole 13 and the second hole 14 formed by polygonal holes with corners, , the inner surface shape of the through hole 10 can be made into a smooth inner surface shape without corners, so it can further prevent the printing paste 4 from adhering to the corners and causing the printed shape of the printed layer on the printing object 2 to become skewed , Printing fading and other poor printing.

When the thickness T of the mask body 7 is set to 1, H1 defined by the hole depth of the first hole portion 13 is preferably set to 0.2 or more and 0.6 or less. This is because the hole depth H1 is less than 0.2 or the hole depth H1 exceeds 0.6, and printing failure occurs. More specifically, if the hole depth H1 is less than 0.2, the guiding effect of the printing paste 4 by the hole inner surface of the first hole portion 13 becomes insufficient, and the printing paste 4 is filled in an unexpected direction during printing. , causing the shape of the printed layer to become distorted, or the printed layer to fade, and as a result, poor printing occurs. Also, if the hole depth H1 exceeds 0.6, the printing paste 4 adheres to the hole inner surface of the first hole portion 13, and part of it and the metal mask are removed, causing the shape of the printed layer to become distorted, or the printed layer to fade, and as a result , resulting in poor printing.

More ideally, when the thickness T of the mask body 7 is set to 1, the H1 specified by the hole depth of the first hole portion 13 is set to be more than 0.2 and less than 0.5. Printing defects occur, and a printed layer with a substantially good thickness can be obtained.

When the hole depth of the 2nd hole portion 14 is defined as H2, and half of the enlarged dimension of the 2nd hole portion 14 is defined as D3, the 2nd hole portion 14 is formed in a manner conforming to the inequality (H2<D3), then the constitution can be Since the curvature of the sectional shape of the hole inner surface of the 2nd hole part 14 formed by the bell-shaped hole is made large, peeling of the printing paste 4 in the 2nd hole part 14 can be accelerated|stimulated.

When the opening size of the first hole portion 13 at the surface 8 of the mask body 7 is specified as D1, and the opening size of the second hole portion 14 at the back side of the mask body 7 at 9 places is specified as D2, the opening size D2 is set as 1.5 times or more of the opening size D1, then similarly to the above, the curvature of the cross-sectional shape of the hole inner surface constituting the second hole 14 formed by the bell-shaped hole can be formed larger, so that the second hole can be promoted to be formed. Stripping of printing paste 4 at 14 places.

The thickness T of the mask body 7 is preferably set to be 25 μm or less. This is because the opening size D1 of the first hole portion 13 is also miniaturized along with the high-definition metal mask for printing. Since the depth of the hole becomes large, filling of the printing paste 4 to the through hole 10 by the doctor blade may become insufficient.

If the coating layer 17 that suppresses the adhesion of the printing paste 4 is formed on the inner surface of the through hole 10 and the back surface 9 of the mask body 7, the printing paste 4 can be smoothly guided through the first hole portion 13. , and the peeling off of the printing paste 4 at the second hole portion 14. In addition, the following form can also be adopted, that is, when the layer thickness of the coating layer 17 formed in the first hole portion 13 is specified as C1, and the layer thickness of the coating layer 17 formed in the second hole portion 14 is specified When C2 is defined and the layer thickness of the coating layer 17 formed on the back surface 9 of the mask body 7 is defined as C3, the coating layer 17 is formed so as to satisfy the inequality (C1≦C2≦C3). In such a form, by setting the layer thickness C1 of the coating layer 17 to be the smallest, it is possible to reduce the shape variation of the opening diameter D1 of the first hole portion 13 which defines the shape of the printed layer. Also, in such a form, by forming the layer thickness C3 of the coating layer 17 to be larger than the layer thicknesses C1 and C2, the effect of the coating layer 17 that is gradually worn away by the contact with the printing object 2 can be maintained for a longer period of time. .

(First Embodiment) FIGS. 1 to 4 show a first embodiment of a metal mask for printing according to the present invention. In addition, dimensions such as thickness and width in each figure are not shown in actual form, but are shown schematically. As shown in FIG. 3 , a metal mask for printing (hereinafter simply referred to as a mask) 1 is used to print and form a printing layer by screen printing. The solder flux (printing paste) 4 on the electrode 3 on the surface of the substrate (printing object) 2 is constituted.

In Fig. 2, the mask 1 is based on the mask body 7 made of thin metal plates, and a plurality of through holes 10 are opened in the mask body 7. The aforementioned thin metal plates are made of nickel, copper, nickel-cobalt. Electrodeposited metal composed of alloy etc. is used as a material, and formed by electroforming, and the above-mentioned through hole is formed by a circular hole penetrating through the disk surface of the mask body from the front surface 8 to the back surface 9 . The mask 1 is formed in a square shape with 250 mm on one side, and when the mask 1 is divided into four quadrants, a pattern formation area M is defined in each quadrant. The through hole 10 is provided in the pattern forming region M in a state of being arranged in an electrode pattern corresponding to the electrode 3 of the circuit board 2 . Around the pattern forming area M, in a manner surrounding the area M, a dicing mark forming area C for printing a dicing mark for cutting the circuit board 2 into a predetermined pattern in a process after screen printing is defined. used for the shape. The mask 1 is attached to the mask fixing part of the screen printing apparatus in a state of being fixed to the periphery of a single body or a frame body.

As shown in FIG. 1 , the through hole 10 is composed of a first hole portion 13 opening toward the front surface 8 of the mask body 7 and a second hole portion 14 opening toward the back surface 9 of the mask body 7 . The first hole 13 is formed of a straight circular hole extending in the thickness direction of the mask body 7 , and the second hole 14 is formed of a bell-shaped hole extending downward smoothly continuous with the first hole 13 .

The thickness T of the mask body 7 is preferably set to be less than 25 μm, more preferably less than 18 μm. In this embodiment, the thickness T of the mask main body 7 is set to 18 μm.

When the thickness T of the mask body 7 is set to 1, the hole depth H1 (see FIG. 1 ) of the first hole portion 13 is set to be 0.2 or more and less than 0.5. The hole depth H1 in this embodiment is set to 3.6 μm, and the hole depth H1 when the thickness T of the mask body 7 is set to 1 is 0.2 (3.6/18=0.2).

The opening size of the first hole 13 , that is, the opening diameter (diameter) D1 (see FIG. 1 ) is set to be the same as the diameter of the layer of flux 4 to be formed on the electrode 3 . Generally, the diameter of the layer of flux 4 is set at 20 μm to 50 μm, therefore, the opening diameter D1 of this embodiment is set at 40 μm. The opening diameter D1 of the first hole portion 13 defines the planar shape of the printed layer formed by printing, and the printed layer is formed on the electrode 3 with a circular shape in plan view.

The hole depth H2 (see FIG. 1 ) of the second hole portion 14 is the thickness T of the mask body 7 minus the hole depth H1 of the first hole portion 13 , and is set to 14.4 μm in this embodiment. As described above, since the hole depth H1 when the thickness T of the mask body 7 is set to 1 is set to be less than 0.5, the hole depth H1 of the first hole portion 13 and the hole depth H2 of the second hole portion 14 The relationship is set in such a way as to satisfy the inequality (H1<H2).

The opening size of the second hole 14, that is, the opening diameter (diameter) D2 (see FIG. 1 ) is set larger than the opening diameter D1, and in this embodiment, the opening diameter D2 is set to be 1.5 times or more the opening diameter D1. Furthermore, the enlarged diameter dimension (half the enlarged dimension of the opening) D3 of the radius of the second hole portion 14 is set to be larger than the hole depth H2 (H2<D3). The enlarged diameter dimension D3 in Fig. 1 refers to half of the value after subtracting the opening diameter D1 from the opening diameter D2 ((D2-D1)/2). The opening diameter (diameter) D2 is ideally set to 50 μm to 100 μm, and the opening diameter D2 in this embodiment is set to 80 μm. Along with this, the enlarged diameter dimension D3 is set to 20 μm. In this embodiment, the relationship between the enlarged diameter dimension D3 and the hole depth H2 is set in a manner that conforms to the inequality (H2<D3), therefore, the cross-sectional shape of the inner surface of the second hole portion 14 is formed to be equal to the thickness of the mask body 7 Orientation Quadrant elliptical arc with minor axis. In addition, the opening end of the second hole portion 14 is smoothly continuous with the back surface 9 of the mask body 7 .

The electrode 3 of the present embodiment is formed in a circular shape. When the diameter of the electrode 3 is D4, the opening diameter D1 of the first hole 13 is formed to be smaller than the diameter D4, and the opening diameter D2 of the second hole 14 is formed to be smaller than the diameter D4. The diameter D4 is large, in other words, the opening diameter D1 and the opening diameter D2 are formed so as to satisfy the inequality (D1<D4<D2) (see FIG. 1 ).

As shown in FIG. 1 , a coating layer 17 is formed on the inner surface of the through hole 10 and the back surface 9 of the mask body 7 . The coating layer 17 is used to prevent the flux 4 from adhering to the inner surface of the through hole 10 and the back surface 9 of the mask body 7 . The layer thickness C1 of the coating layer 17 at the first hole 13, the layer thickness C2 of the coating layer 17 at the second hole 14, and the layer thickness C3 of the coating layer 17 at the 9 back sides of the mask body 7 Set to satisfy the inequality (C1≦C2≦C3). Also, since the inner surface of the hole of the first hole portion 13 defines the shape of the printing layer, the layer thickness C1 of the coating layer 17 at this portion is formed thinner than other portions, whereby the shape change of the opening diameter D1 can be made small. The back surface 9 of the mask body 7 is in contact with the circuit board 2 when the metal mask 1 for printing is used. Therefore, by forming the layer thickness C3 of the coating layer 17 at this part thicker than other parts, its durability can be improved. sex. Therefore, the thicknesses C1, C2, and C3 of the coating layer 17 are set so as to satisfy the inequality (C1≦C2≦C3) and the expression (C1≠C3).

The layer thickness C1 of this embodiment is set to 0.5 μm, and in the layer thickness C2, the portion adjacent to the first hole 13 is set to 0.5 μm, and the portion adjacent to the back surface 9 of the mask body 7 is set to 1.0 μm, and the layer thickness C3 is set to 1.0 μm. The layer thickness C2 of the coating layer 17 at the second hole portion 14 is formed gradually thicker from the first hole portion 13 side toward the back surface 9 side of the mask body 7, as a smooth coating layer 17 without a step. The coating layer 17 can be formed by dipping or spray coating. Furthermore, the coating layer 17 in this embodiment is formed on the order of microns (μm), but the coating layer 17 may also be formed on the order of nm.

In addition, the coating layer 17 may also be set so as to satisfy the inequality (C1<C2<C3). Specifically, when the layer thickness C3 is 1, the layer thickness C1 is set to be less than 0.5, and the layer thickness C2 is set to be more than 0.5 and less than 1.

The surface 8 of the mask body 7 constitutes the scraper surface, and when the printing of the printing layer made of the flux 4 is performed, the back surface 9 of the mask body 7 faces the surface of the circuit board 2, and the electrode 3 is connected to the communication layer. In the state where the holes 10 are facing each other, the two (the mask 1 and the circuit board 2) are closely connected. Printing is to scrape the flux 4 placed on the scraper surface (surface 8) with a scraper S, and fill the flux 4 into the through hole 10 and the opening for cutting marks, so that the through hole is formed on the surface of the circuit board 2. 10 and the printing layer made of flux 4 matching the cutting marks. The scraper S moves from the front of the mask 1 (the lower side in FIG. 2 ) to the deep side (the upper side in FIG. 2 ) while its front end is in contact with the scraper surface (the surface 8 of the mask body 7 ). Printing forms the print layer.

The flux 4 during printing is filled from the surface 8 of the mask body 7 to the inside of the first hole 13 . The flux 4 that has penetrated into the through hole 10 is guided by the inner surface of the first hole portion 13 , and penetrates in a state where the filling direction is the thickness direction of the mask body 7 , that is, falls toward the electrode 3 . The flux 4 intruded into the inside of the through hole 10 is peeled off from the second hole 14 at the boundary portion between the first hole 13 and the second hole 14 and goes toward the electrode 3 and reaches the back surface 9 of the mask body 7. The flux 4 is in contact with the electrode 3 to form a printed layer composed of the flux 4 as shown in FIG. 3 .

FIG. 4 shows a manufacturing method of the mask 1 of the embodiment. (pattern structure process) As shown in Figure 4 (a), after forming a photoresist layer 22 with a predetermined thickness on the entire surface of a conductive master mold 21 such as stainless steel or brass, make a circular shape corresponding to the through hole 10 and a The linear light-transmitting holes corresponding to the cutting marks are in close contact with the patterned film 23 made of a glass mask. In this state, exposure is performed by irradiating ultraviolet light, and various processes such as development and drying are performed. The photoresist layer 22 referred to here is formed by laminating one or a plurality of sheets of negative-type sheet-shaped photosensitive dry film photoresist and fixing them by thermocompression bonding to have a predetermined thickness. Next, by dissolving and removing the photoresist layer 22 of the unexposed part, as shown in FIG.

(Electroforming process) Put it into the electroforming tank of the master mold 21 that forms the photoresist 25 of the aforementioned pattern, as shown in Figure 4 (c), under the range that will not exceed the upper edge of the photoresist body 24, carry out electrodeposition metal Electrodeposition, forming an electroformed layer 26, that is, forming a layer as a mask body 7. At this time, since the edge of the growing front end of the electroformed metal grows into a quadrant elliptical arc shape, the bell-shaped second hole 14 can be formed only by electrodepositing the electrodeposited metal on the master mold 21 .

(Peel-off process) As shown in Figure 4(d), the electroformed layer 26 and the patterned photoresist 25 are peeled off from the master mold 21, and the patterned photoresist 25 is dissolved and removed, thereby obtaining the mask 1 as shown in Figure 3 . Furthermore, the outer peripheral edge of the obtained mask body 7 may be bonded to the frame by an adhesive to make the mask 1 with the frame in which the mask body 7 and the frame are inseparably bonded.

As described above, in the mask 1 of the present embodiment, since the first hole 13 opening toward the surface 8 of the mask body 7 is constituted by a straight hole, it is possible to dissipate the flux when filling the through hole 10. The flow direction of flux 4 is guided by the inner surface of the first hole portion 13 extending in the vertical direction, so that the flux 4 can surely fall into the thickness direction (vertical direction) of the mask body 7 . Also, the second hole 14 is formed in an R-shaped cross-sectional shape on the inner surface, and is formed as a bell-shaped hole that is smoothly continuous with the first hole 13 and expanded to open on the back surface 9 of the mask body 7. When the flux 4 is guided by the inner surface of the first hole 13 and reaches the vicinity of the boundary between the two holes 13 and 14, the flux 4 can be peeled off from the inner surface of the second hole 14 near the boundary. . In addition, the flux 4 can reach the back surface 9 side of the mask main body 7 of the second hole 14 in a state where it has been peeled off from the hole inner surface of the second hole 14 . Thus, according to the mask 1 of this embodiment, since the flux 4 can be peeled off from the hole inner surface of the second hole portion 14 in the vicinity of the boundary portion of the two hole portions 13 and 14, compared with the conventional metal mask The mask can reduce the contact area between the inner surface of the through hole 10 and the flux 4, and when the mask 1 is separated from the circuit board 2, the amount of the flux 4 attached to the mask 1 and removed from the circuit board 2 can be reduced. volume reduction. As described above, according to the mask 1 of this embodiment, printing defects such as distortion of the printed shape of the printed layer on the circuit board 2 and printing fading can be suppressed, so that the printing accuracy can be improved when the printed layer is formed by printing. As a result, a high-precision and high-quality printed layer can be formed on the circuit board 2 .

Also, according to the through hole 10 constituted by the first hole portion 13 constituted by a straight circular hole and the second hole portion 14 constituted by a bell-shaped hole, the inner surface shape of the through hole 10 can be made different. The rounded inner surface shape of the corners can further suppress printing failures such as distortion of the printed shape of the printed layer on the circuit board 2 and fading of the printing caused by the adhesion of the flux 4 to the corners.

When the thickness T of the mask body 7 is set to 1, H1 defined by the hole depth of the first hole portion 13 is preferably set to 0.2 or more and 0.6 or less. This is because the hole depth H1 is less than 0.2 or the hole depth H1 exceeds 0.6, and printing failure occurs. More specifically, if the hole depth H1 is less than 0.2, the guiding effect of the flux 4 by the inner surface of the first hole 13 becomes insufficient, and the flux 4 is filled in an unexpected direction during printing. , causing the shape of the printed layer to become distorted, or the printed layer to fade, and as a result, poor printing occurs. Also, if the hole depth H1 exceeds 0.6, the flux 4 adheres to the hole inner surface of the first hole portion 13, and part of it and the metal mask are removed, causing the shape of the printed layer to become distorted, or the printed layer to fade, and as a result , resulting in poor printing.

Moreover, when the thickness T of the mask body 7 is set to 1, it is more preferable to set H1 specified by the hole depth of the first hole portion 13 to 0.2 or more and less than 0.5, thereby suppressing subsequent printing failures. Produced, a printing layer with a substantially good thickness can be obtained.

When forming the second hole portion 14 in such a way that the hole depth H2 of the second hole portion 14 and the enlarged diameter dimension D3 of the radius of the second hole portion 14 conform to the inequality (H2<D3), then the structure can be formed by the bell-shaped hole. The curvature of the cross-sectional shape of the hole inner surface of the formed second hole portion 14 is large, so that the peeling of the flux 4 at the second hole portion 14 can be accelerated.

Because the opening diameter D2 of the second hole portion 14 is set to be more than 1.5 times the opening diameter D1 of the first hole portion 13, it is possible to configure the second hole portion 14 formed by the bell-shaped hole in the same manner as described above. The curvature of the cross-sectional shape of the inner surface of the hole is formed relatively large, which can promote the peeling of the flux 4 at the second hole portion 14 .

The opening diameter D1 of the first hole portion 13 is also miniaturized as the mask 1 becomes more high-definition. However, if the thickness T of the mask body 7 becomes larger, the hole depth of the through hole 10 becomes larger with respect to the opening diameter D1. Therefore, there is a possibility that the filling of the flux 4 to the through hole 10 by the scraper becomes insufficient. In this embodiment, since the thickness T of the mask body 7 is set to be 25 μm or less (18 μm), the above-mentioned problems will not occur, and it can be avoided that the filling of the flux 4 toward the through hole 10 by the scraper becomes insufficient. full question.

Because the coating layer 17 that suppresses the adhesion of the flux 4 is formed on the inner surface of the through hole 10 and the back surface 9 of the mask body 7, the flux 4 can be smoothly guided through the first hole 13. lead, and the peeling of the flux 4 at the second hole portion 14. In addition, in the state where the respective layer thicknesses C1, C2, and C3 of the coating layer 17 conform to the inequality (C1≦C2≦C3), the layer thickness C1 is set to be the minimum, so that the first hole portion that defines the shape of the printed layer can be The shape change of the opening diameter D1 of 13 becomes small. In addition, since the layer thickness C3 is formed to the maximum, the effect of the coating layer 17 which is gradually worn away due to contact with the circuit board 2 can be maintained for a longer period of time.

As can be seen from the above description, the metal mask for printing in this embodiment can contribute to goal 9 of the Sustainable Development Goals (SDGs: Sustainable Development Goals) advocated by the United Nations (building resilient infrastructure, promoting inclusiveness and sustainable development) industrialization and promote innovation) and Goal 12 (ensure sustainable consumption and production patterns).

(Second Embodiment) FIG. 5 shows a second embodiment of the printing metal mask of the present invention. In this embodiment, the shape of the through hole 10 is different from that of the first embodiment. Moreover, in FIG. 5, the coating layer 17 is omitted and shown in the figure. In FIG. The line of the opening end of the second hole portion 14 opened on the back surface 9 side of the mask body 7 .

The through hole 10 is constituted by making the first hole 13 opening on the surface 8 of the mask body 7 a straight square hole (rectangular hole), and making the second hole 14 opening on the back surface 9 of the mask body 7 It is smoothly continuous and enlarged with the first hole portion 13 , and the cross-sectional shape of the inner surface thereof is formed in an R shape. The cross-sectional shape of the inner surface of the second hole 14 also includes quadrant circular regions at the four corners of the second hole 14 viewed from the bottom surface, and is formed as a quadrant ellipse having a minor axis in the thickness direction of the mask body 7. arc. Thus, the through-hole 10 may be rectangular or polygonal, and the through-hole 10 formed of a rectangular or polygonal hole may have its corners rounded. The through hole 10 may also be formed in an oval shape.

When the length of one side of the square hole constituting the first hole portion 13 of the present embodiment is taken as the opening size D1 of the first hole portion 13, the opening size D1 is different from the opening size of the first hole portion 13 of the previous first embodiment. The caliber D1 is the same. Under this condition, compared with the first embodiment, the opening area of the first hole portion 13 opening on the surface 8 of the mask body 7 of the present embodiment is approximately 1.3 times larger. Therefore, in the case where it is difficult to form the metal mask 1 for printing with a large opening diameter (opening size) D1, and it is desired to print more flux 4 on the electrode 3, the first hole portion with the opening shape of this embodiment 13 is extremely effective. Moreover, it is also effective for the case where the electrode 3 is comprised in the square shape (rectangular shape, polygonal shape).

(Third Embodiment) FIG. 6 shows a third embodiment of the printing metal mask of the present invention. In this embodiment, the structure of the through hole 10 is different from that of the first embodiment. Specifically, in the first embodiment, the second hole portion is used as the front side of the mask body, and the first hole portion is used as the back side of the mask body. In addition, in FIG. 6, the coating layer 17 is abbreviate|omitted and shown in figure.

The through hole 10 of this embodiment is formed by the first hole 13 opened on the surface (scraper surface) 8 of the mask body 7 and the second hole opened on the back surface (circuit board facing surface) 9 of the mask body 7. Section 14 constitutes. The second hole portion 14 is made of a straight circular hole extending in the thickness direction of the mask body 7, and the first hole portion 13 is smoothly continuous with the second hole portion 14 and constituted by an upwardly expanding bell-shaped hole, and its The cross-sectional shape of the inner surface is R-shaped. In this way, if the first hole portion 13 opening toward the surface 8 of the mask body 7 is configured as a bell-shaped hole, the printing paste when filling the through hole 10 can be formed in the R-shaped first hole portion 13 in cross-section. The inner surface of the hole is guided, so that the printing paste 4 can be surely drawn into the through hole 10 . Also, the second hole portion 14 connected to the first hole portion 13 is formed in a straight shape, smoothly continuous with the first hole portion 13 and opened on the back surface 9 of the mask body 7, so the printing paste 4 is covered by the first hole portion. The inner surface of the hole of 13 is guided to reach the vicinity of the boundary portion of the two hole portions 13 and 14, guided and filled in the second hole portion 14, so that the printing paste 4 can reach the back side of the mask body 7 of the second hole portion 14 9 sides. In this way, according to the printing metal mask of the present embodiment, the printing paste 4 guided by the first hole portion 13 gathers near the boundary portion of the two hole portions 13 and 14, and moves toward the inside of the second hole portion 14. Therefore, even if the printing paste 4 comes into contact with the hole inner surface of the through hole 10, it can be guided toward the printing object 2. As described above, according to the metal mask for printing of this embodiment, printing defects such as distortion of the printed shape of the printed layer on the printing object 2 and printing fading can be suppressed, so that printing can be achieved when the printed layer is formed by printing. The improvement of precision can form a high-precision and high-quality printing layer on the printing object 2 .

In the metal mask for printing of the present invention, when the coating layer 17 is formed, it is preferably formed on the back surface (circuit board facing surface) 9 of the mask main body 7 . Also, when the coating layer 17 is formed on the hole inner surface of the through hole 10, it is preferably formed only on the hole inner surface of the second hole portion 14. This is because if the coating layer 17 is formed on the surface (squeegee surface) 8 of the mask body 7, or the hole inner surface of the first hole portion 13, when the scraper S scrapes the printing paste 4, the printing paste 4 cannot rotate. There is a risk that good printing (guiding and filling into the through hole 10 ) cannot be performed. Furthermore, when the coating layer 17 is formed on the back surface 9 of the mask body 7 and the hole inner surface of the second hole portion 14, the thickness of the coating layer 17 on the back surface 9 of the mask body 7 is formed larger than that of the second hole. The thickness of the coating layer 17 on the inner surface of the hole of the portion 14 is preferable. In addition, in the metal mask for printing according to the first embodiment, the opening dimension (diameter) D1 of the first hole 13 is formed smaller than the length dimension (diameter) D4 of the electrode 3, and the opening dimension (diameter) of the second hole 14 ( The opening diameter) D2 is formed so that the length dimension (diameter) D4 of the electrode 3 is large, and the shape of the printing layer printed on the printing object 2 by such a structure is formed from the upper surface side to the lower surface side and the first The opening size (opening diameter) D1 of the hole 13 is the same as the columnar body, or the size of the upper surface side is the same as the opening size (opening diameter) D1 of the first hole 13, and the size increases toward the lower surface side (printing object 2 Side) The gradually expanding cross-sectional mountain shape. On the other hand, in the metal mask for printing of this embodiment, the opening size (opening diameter) D1 of the first hole 13 is formed larger than the length (diameter) D4 of the electrode 3, and the opening size (diameter) of the second hole 14 ( The opening diameter) D2 is formed to be smaller than the length dimension (diameter) D4 of the electrode 3, and the shape of the printing layer printed on the printing object 2 by such a structure is formed so that the printing paste 4 is filled in the through hole 10. A columnar body having the same size as the opening size (opening diameter) D2 of the second hole 14 from the upper surface side to the lower surface side. In this way, the metal mask for printing of this embodiment is formed in a straight shape by opening the second hole portion 14 on the back surface 9 of the mask. The entire inner surface of the hole 10 is in contact with each other. When the metal mask for printing is separated from the printing object 2, the printing paste 4 located on the inner surface of the hole of the second hole portion 14 can also be printed on the printing object 2. Compared with The cross-sectional shape of the inner surface of the through hole is an R-shaped metal mask, which can reduce the amount of printing paste 4 attached to the inner surface of the through hole 10 and removed from the printing object 2 . Therefore, according to the metal mask for printing of this embodiment, the printed layer formed on the printed object 2 can be printed with uniform thickness and high reproducibility.

In the aforementioned embodiment, the cross-sectional shape of the inner surface of the second hole 14 is formed into a quadrant elliptical arc shape having a minor axis in the thickness direction of the mask body 7, but it may also be formed so that Quadrant ellipse arc or arc with long axis. That is, the cross-sectional shape of the inner surface of the second hole portion 14 is an R-shape protruding toward the hole center side. For example, the cross-sectional shape of the inner surface of the second hole portion 14 can also be an R shape in which the curvature near the first hole portion 13 and the back surface 9 of the mask body 7 is large, and the curvature of the middle portion is small. 1 The R shape that changes between the hole portion 13 and the back surface 9 of the mask body 7. Also, in the aforementioned embodiment, the printing metal mask 1 is directly placed on the printing object 2 to perform contact printing, but it is also possible to provide a distance between the printing object 2 and the printing metal mask 1. Non-contact printing for printing. The technology of the present invention is not limited to metal masks for printing, but can also be transferred to metal masks such as vapor deposition masks, solder ball arrangement masks, and solder ball adsorption masks.

1: Metal mask for printing 2: Printing object (circuit board) 4: Printing (flux, paste) 7: Mask body 8: Mask the surface of the body 9: Mask the back of the body 10: Through hole 13: The first hole 14: The second hole 17: Coating layer D1: Opening size of the first hole (opening diameter) D2: Opening size of the second hole (opening diameter) D3: One half of the enlarged dimension of the opening of the second hole (diameter enlarged dimension of the radius) D4: The length dimension (diameter) of the electrode D5: One half of the enlarged dimension of the opening of the first hole (diameter enlarged dimension of the radius) H1: Hole depth of the first hole H2: Hole depth of the second hole T: Thickness of the mask body

[FIG. 1] It is a longitudinal front view which shows the main part of the metal mask for printing which concerns on the 1st Embodiment of this invention. [Fig. 2] is a plan view showing the entire metal mask for printing. [Fig. 3] is a vertical side view showing an example of a metal mask for printing in use. [Fig. 4] is an explanatory diagram showing the manufacturing process of a metal mask for printing. [ Fig. 5 ] shows main parts of a metal mask for printing according to a second embodiment of the present invention, wherein (a) is a longitudinal front view, and (b) is a bottom view. [ Fig. 6] Fig. 6 is a vertical side view showing an example of the usage state of the printing metal mask according to the third embodiment of the present invention.

1: Metal mask for printing

2: Printing object (circuit board)

3: electrode

7: Mask body

8: Mask the surface of the body

9: Mask the back of the body

10: Through hole

13: The first hole

14: The second hole

17: Coating layer

C1: layer thickness

C2: layer thickness

C3: layer thickness

D1: Opening size of the first hole (opening diameter)

D2: Opening size of the second hole (opening diameter)

D3: One half of the enlarged dimension of the opening of the second hole (diameter enlarged dimension of the radius)

D4: The length dimension (diameter) of the electrode

H1: Hole depth of the first hole

H2: Hole depth of the second hole

T: Thickness of the mask body

Claims (8)

A metal mask for printing, characterized by comprising: a mask body (7), which is made of a thin metal plate, and the back surface (9) faces the printing object (2); and A plurality of through holes (10), which penetrate the mask body (7) towards the front and back, and are filled with printing paste (4), The through hole (10) is opened toward the surface (8) of the mask body (7) and is a first hole portion (13) made of a straight hole; (13) The second hole portion (14) that is smoothly continuous and enlarged, and opens toward the back surface (9) of the mask body (7) is formed. The metal mask for printing according to claim 1, wherein the first hole portion (13) is composed of a straight circular hole, and the second hole portion (14) is composed of a bell-shaped hole. The metal mask for printing as claimed in claim 1 or 2, wherein when the thickness (T) of the mask body (7) is set to 1, the hole depth (H1) specified by the first hole portion (13) Set to 0.2 or more and 0.6 or less. The metal mask for printing as claimed in claim 1 or 2, wherein when the thickness (T) of the mask body (7) is set to 1, the hole depth (H1) specified by the first hole portion (13) Set to 0.2 or more and less than 0.5. The metal mask for printing as claimed in claim 1 or 2, wherein, when the hole depth of the second hole (14) is specified as (H2), half of the enlarged size of the second hole (14) is specified as (D3 ), the second hole portion (14) is formed so as to satisfy the inequality (H2<D3). The metal mask for printing as claimed in claim 1 or 2, wherein, when the opening size of the first hole (13) of the surface (8) of the mask body (7) is specified as (D1), the mask body (7 ) when the opening size of the second hole (14) on the back side (9) is specified as (D2), the opening size (D2) is set to be more than 1.5 times the opening size (D1). The metal mask for printing according to claim 1 or 2, wherein the thickness (T) of the mask body (7) is set to be 25 μm or less. The metal mask for printing as claimed in claim 1 or 2, wherein a coating for inhibiting the adhesion of printing paste (4) is formed on the inner surface of the through hole (10) and the back surface (9) of the mask body (7). cloth layer (17), When the layer thickness of the coating layer (17) at the first hole (13) is specified as (C1), the layer thickness of the coating layer (17) at the second hole (14) is specified as (C2), When the layer thickness of the coating layer (17) at the back side (9) of the mask body (7) is specified as (C3), the coating layer (17) is formed in a manner satisfying the inequality (C1≦C2≦C3).

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