JP2008290351A - Metal mask for printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal mask for printing, a metal mask in which printing durability is improved without changing a method and conditions of forming the opening part of the mask and with printing transferability maintained in the metal mask for use in screen printing. <P>SOLUTION: In the metal mask 101 for printing, a projection 107 made of a resin material is provided, in a part with which an end of a substrate to be printed comes in contact during the printing and in a part which is parallel to the moving direction of a squeegee. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a printing metal mask used for screen printing and the like and a printing plate using the same.

In order to mount an electronic component, a method of forming a bump by screen-printing a conductive paste has been widely used. In recent years, there has been a demand for higher density mounting of electronic components, and accordingly, printing metal masks used for screen printing have been made thinner. However, as the printing metal mask (abbreviated as “mask”) becomes thinner, defects that damage the mask during printing tend to occur.

Hereinafter, a problem that a conventional mask is damaged will be described with reference to FIG.
When the conductive paste is printed using a mask, a local force is applied by a squeegee to the portion where the mask (101) contacts the end portion (106) of the substrate to be printed (abbreviated as substrate) (104). If printing is repeated in this state, the mask is damaged. Further, some substrates have a shape in which burrs protrude from the end portion (106) as shown in FIG. 2, which accelerates damage to the mask. If the damage is severe, the mask becomes unusable, the mask must be replaced, requires a lot of labor, and is economically problematic.

In particular, as the mask is thinned for high-density mounting of electronic components as described above, the frequency at which the mask becomes unusable due to damage increases, and it is strongly desired to improve the durability of the mask.

As a method of manufacturing a mask for high-density mounting, an additive method by plating or a method of processing with a laser is generally used, and conventionally, durability has been improved by increasing the material strength of the mask.
For example, in the additive method, the durability is improved by changing the metal to be plated, the plating conditions, and the method of processing with a laser by changing the substrate material to be used.

However, sufficient durability cannot be obtained only by changing the production conditions, and further improvement in durability is desired. In addition, when the production conditions are changed, the state of the opening for conductive paste printing (hereinafter abbreviated as “opening”) changes, resulting in a problem that print transferability is lowered.

Furthermore, since it is necessary to study the mask manufacturing conditions and to adjust the printing conditions associated with the mask change, there is a problem that much labor and cost are required.

As a method for improving the durability of the mask, a metal mesh is laminated on a plate having a tetron mesh attached to a metal frame, metal plating is performed on the metal mesh portion, and then an opening is formed in the metal portion by etching. A method for manufacturing a mask is disclosed.
JP-A-6-83067

However, since the mask manufactured by the above-described method has a mesh in the opening, the conductive paste cannot be easily removed and cannot be used for printing for high-density mounting. Furthermore, since it has a structure in which two types of meshes are laminated, it is difficult to cope with a reduction in thickness.

The present invention improves the durability of a mask while maintaining print transferability in a mask used for printing a conductive paste by screen printing to form bumps for high-density mounting.

The inventors of the present invention have studied the mask for high-density mounting with improved durability while maintaining print transferability, and completed the present invention.
That is, the present invention
A printing metal mask used for screen printing or the like, wherein the printing metal mask has a protruding portion at a portion parallel to a moving direction of a squeegee at a portion where an end portion of a substrate to be printed contacts. A metal mask for printing, characterized in that is made of a resin material, and a metal mask plate for printing in which the above-described metal mask for printing is attached to a frame through a ridge.

The present invention can improve the durability of the mask without changing the conventional method of forming the opening of the mask, and without impairing the print transferability.

The mask of the present invention and a printing metal mask plate (abbreviated as printing plate) using the mask will be specifically described below.
FIG. 3 shows an example of a printing plate in which the mask of the present invention is bonded to a frame through a ridge. FIG. 4 shows an enlarged view of part b of FIG.
The mask (101) of the present invention has a protrusion (107) at a portion in contact with the substrate (104), and is bonded to the frame (103) through a ridge (102).

  These protrusions can be provided in a part or all of the portion where the end of the substrate contacts during printing. However, in order to prevent the smooth movement of the squeegee during printing, as shown in FIG. It is desirable to provide it continuously in parallel. Also, it is desirable to round the corners of the protrusions. The shape of the protrusion is not particularly limited, but the height is preferably about 10 to 100 μm and the width is preferably about 5 to 40 mm.

  The mask manufacturing method of the present invention will be described. First, a mask in which an opening is formed is prepared by a known method such as a laser processing method, a plating method, or an etching method. Next, a protrusion is formed. As a method for forming the protrusion, a protrusion member made of a resin material such as polyimide is bonded to the protrusion. In addition, the mask of the present invention can be manufactured by forming the opening after forming the protrusion by a laser processing method or an etching processing method.

Although the manufacturing method of a mask is not specifically limited, It is desirable to produce by masking with favorable print transferability.

The resin material of the protruding member is not particularly limited, but polyimide is desirable in consideration of durability during printing.

The method for adhering the protruding member to the mask is not particularly limited, but in order to ensure the uniformity of the plate thickness, the method is a method of attaching with an adhesive sheet having a uniform thickness, or a plurality of through holes are provided in the protruding member, and the protruding member It is desirable that a method of injecting an adhesive into the through hole of the projecting member and then adhering it to the pasting portion of the mask surface.

The type of adhesive for adhering the protruding member to the mask is not particularly limited, but in order to prevent the protrusion from peeling off when using the mask and cleaning, an epoxy system, a cyanoacrylate system with good chemical resistance and adhesive strength, An acrylic type, a phenol resin type, etc. are mentioned.

When bonding the protruding member to the mask, the ten-point average roughness (Rzjis) is set to 0.02 by physical polishing, chemical polishing or the like on the bonding surface of the mask and / or the protruding member in order to improve the adhesive force with the mask. It is desirable to roughen the surface to about 20 μm.

  The protrusion member may be bonded before the mask is peeled off from the plating base material, before the mask is attached to the frame through the ridge, or after the attachment.

It is desirable to use the mask of the present invention by attaching it to a frame through a ridge. The type of the ridge is not particularly limited, but a polyester mesh or a metal mesh is desirable.
Specific examples are shown below.

A dry film resist is laminated on a plating base material made of SUS304, ultraviolet rays are irradiated through an exposure mask on which an image pattern is formed, and development is performed to remove the resist in a portion not irradiated with ultraviolet rays. An image corresponding to the opening was formed with a resist. About 30 μm of Ni plating was deposited on the plating base material on which this image was formed by a conventional method, and the remaining dry film resist was peeled off.

The protruding member was attached to the mask with an epoxy thermosetting adhesive sheet (thickness 30 μm, width 20 mm). As shown in FIG. 5, the position where the protruding member is bonded is a portion parallel to the moving direction of the squeegee among the portions where the end of the substrate contacts at the time of printing, and the end of the substrate orthogonal to the moving direction of the squeegee is used. The substrate was pasted so that the end of the substrate was positioned approximately at the center of the width of the adhesive sheet. In this way, the mask to which the protrusions were bonded was peeled off from the plating base material to produce the mask of the present invention. The protruding member was prepared by cutting a polyimide sheet having a thickness of 20 μm into a strip shape (width 20 mm) with rounded corners.

Next, the outer periphery of the mask is bonded to the center of the mesh screen plate attached to the metal frame in a state where a 180 mesh polyester ridge is applied, and the polyester fold inside the bonded portion is cut off. A printing plate was prepared.

  The printing durability and print transferability of the printing plate produced in Example 1 and a printing plate using a mask without projections were evaluated as comparative examples. As a result, although the printing durability of the mask of Example 1 was able to be printed 2000 times or more, the mask of the comparative example was damaged at 950 times and became unusable. Both print transfer properties were good.

  After forming an image corresponding to the opening with a dry film resist in the same manner as in Example 1, Ni plating was deposited on the plating base material with a thickness of about 30 μm, and the remaining dry film resist was peeled off. A mask having an opening was prepared by peeling off. Next, the outer peripheral portion of the mask is bonded to a mesh screen plate attached to a metal frame in a state where a 180 mesh polyester bag is applied with tension, and the polyester plate inside the bonded portion is cut off to obtain a printing plate. Produced.

  Next, the same protruding member as used in Example 1 was attached to the printing plate at the same position as in Example 1 with a liquid adhesive. However, through holes having a diameter of 0.5 mm were formed in the protruding member at a pitch of 2 mm, and a cyanoacrylate adhesive was injected and pasted from the through holes.

When the printing durability of the printing plate produced in Example 2 was evaluated, printing of 2000 times or more was possible.

The mask of the present invention can improve the durability of the mask without changing the conventional mask manufacturing method and without impairing the print transferability.

Metal mask plate for printing using conventional mask Enlarged view of part a in FIG. Sectional view of printing metal mask plate of the present invention Enlarged view of part b in FIG. The figure which looked at the metal mask plate for printing of the present invention from the top

Explanation of symbols

101: metal mask for printing 102: collar 103: frame 104: printed substrate 105: squeegee 106: substrate edge 107: protrusion 108: opening 109: position of substrate edge during printing

Claims (2)

In printing metal masks used for screen printing, etc., printing is characterized in that a protrusion made of a resin material is formed in a portion parallel to the moving direction of the squeegee at the portion where the end of the substrate to be printed contacts. Metal mask for use. A printing metal mask plate comprising the printing metal mask according to claim 1 attached to a frame through a ridge.

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