JPH07195857A - Screen printing - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide a screen printing method for forming a print pattern in a concave portion, which method enables high-precision printing without bleeding. A printing method using a special screen mask having a concave-section printing mask portion 16 and a mask portion 15 in which the concave-portion printing mask portion 16 is thicker than the mask portion 15 in accordance with the depth of the concave portion 11a of the printing object 11. It is a law.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing method for forming a print pattern on the bottom surface of a recess when the print surface of the substrate has a recess.

[0002]

2. Description of the Related Art The conventional printing method described above is shown in FIGS.
Use to explain. In FIG. 2A, reference numeral 1 is a printed material having a concave portion 1a, 2 is a paste to be printed on the concave portion 1a of the printed material 1, 3 is a squeegee rubber being printed, and from left to right in FIG. 2A. Is moving to. Numerals 4 and 5 are screen masks for forming a print pattern, numeral 4 is a mesh portion, and numeral 5 is a patterned mask portion.

The printing method will be described below. In FIG. 2A, the printing pressure of the squeegee rubber 3 causes
The screen mask (4, 5) prints the paste 2 on the bottom surface of the concave portion 1a of the substrate 1 while deforming in the concave portion 1a.
As shown in FIG. 2A, since the mask portion 5 of the screen mask on the surface of the printed material does not come into contact with the bottom surface of the concave portion 1a during printing, a print bleed occurs in the coating film of the paste 2. Due to this phenomenon, the print pattern size becomes large due to printing bleeding, as shown in FIG. 2B, and causes a short circuit of the pattern when a conductor paste is used as the paste 2.

[0004]

However, in the above-mentioned conventional screen printing method, when the print pattern is formed in the recess 1a of the substrate 1, the pattern of the paste 2 is bleeding, and therefore the screen printing is performed in the recess 1a. The method was not used, and I was printing with tampon printing etc.,
The thickness of the coating film cannot be obtained by tampon printing.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a screen printing method using a special screen mask for printing recesses.

[0006]

In order to achieve this object, the screen printing method of the present invention uses the thickness of the recess forming mask to the depth of the recess forming mask relative to the thickness of the mask forming the outer peripheral portion of the recess of the substrate. The method uses a special screen mask thickened according to the above.

[0007]

In the screen printing method using the above special screen mask, when the printing pattern of the concave portion of the printing object is formed,
Since the thick mask for forming the recess is inserted into the recess of the substrate and can be printed in close contact with the bottom of the recess, bleeding of the paste pattern can be sufficiently suppressed and pattern printing of the recess can be facilitated. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 (a) and 1 (b), reference numeral 11 denotes a printing substrate, which is a ceramic substrate having a recess 11a, and the depth of the recess 11a is about 100 to 150 μm. Reference numeral 12 is an Ag paste for printing on the concave portion, and reference numeral 13 is a squeegee rubber which is in the middle of printing and progresses from left to right in the figure. 1
4, 15 and 16 are special screen masks, 14 is a mesh portion, 15 is a mask portion for forming the outer peripheral portion of the concave portion 11a, and 16 is a concave portion printing mask portion. This screen mask is composed of a mesh portion 14 in which a stainless wire wire is knitted and a photosensitive emulsion portion (mask portion 15) formed by pattern-exposing a print pattern on a film obtained by coating the mesh portion 14 with a photosensitive emulsion.

The main component of the photosensitive material of the mask portion 15 is an emulsion obtained by emulsion-polymerizing vinyl acetate in an aqueous polyvinyl alcohol solution to which a diazo resin is added as a photosensitive agent, and other additives (epoxy resin etc.). The amount adjusts the photosensitivity during exposure of the film, and also adjusts the organic solvent resistance (mainly during mask cleaning) and the side edge property during exposure.

In the step of forming the step emulsion mask of the present invention,
Repeat emulsion coating and film exposure twice,
Two types of mask thickness are formed. First, in order to make the emulsion thickness of the mask portion 15 other than the concave portion 5 to 50 μm, the emulsion A is applied to the mesh portion 14 stretched on the plate frame, and is exposed to ultraviolet light using the positive film having the printing pattern of the concave portion 11a. Emulsion B is applied on the concave portion printing mask portion 16 so as to have a thickness (100 to 150 μm) corresponding to the depth of the concave portion 11a, and after drying, the concave portion printing mask portion 1 is formed.
Positioning is performed using a positive film having a formation pattern of 6 so as not to be displaced from the pattern alignment position at the time of the first exposure, ultraviolet exposure is performed, and unnecessary emulsion portions are removed by etching to complete the process.

Emulsion A was selected to have a strong organic solvent resistance in an organic solvent screen mask washing step and a film quality capable of withstanding the printing pressure load of squeegee rubber 13 during printing. Emulsion B increases the photosensitivity even when the emulsion portion (mask portion) is thicker by increasing the compounding ratio of the light-sensitive material than emulsion A. In order to reduce the amount of side edges (pattern error) due to the wraparound) and to give the mask part flexibility so that cracks do not occur during printing, the film quality of the mask part was selected to be soft. Emulsion A and Emulsion B were changed in color by additives such as colorants so that the two kinds of emulsion materials could be handled correctly and alignment was easily performed during film exposure. However, even when the emulsion A and the emulsion B are the same, they can be used if the emulsion is selected in consideration of the above problems.

The size of the concave printing mask portion 16 of this special screen mask with respect to the size (width, length) other than the depth of the concave portion 11a of the printing material 11 is such that the concave printing mask portion is formed in the concave portion 11a during printing. At least 50 μm smaller than the size of the recess 11a so that 16 can be inserted.

The method of printing the recess will be described below with reference to FIG. FIG. 1A shows a special screen mask (14, 15, 16) on a substrate 11 having a recess 11a.
FIG. 6 is a cross-sectional view during printing using the. Squeegee rubber 13
Is advancing in the direction of the arrow while pressing the screen mask downward with the printing pressure. At this time, the concave printing mask portion 16
Since the Ag paste 12 can be printed while being in contact with the bottom surface of the concave portion 11a, the concave portion 1 can be printed as shown in FIG.
It was possible to form a printed coating film having very little bleeding of the printed pattern 1a. Further, after the Ag paste 12 is dried, the Ag paste 12 is baked in a baking furnace at a peak temperature of 700 to 900 ° C. for a peak time of 5 to 20 minutes, and the coating film is baked on the printing object 11.

Further, in the embodiment, the thickness of the mask portion for printing the concave portion of the special screen mask of the present invention is described with respect to two kinds of thickness in total, that is, the thickness of the mask portion 15 other than the concave portion. In this case, various shapes can be coped with by using a screen mask having three or more kinds of mask portion thicknesses. Further, in the embodiment, the depth of the concave portion 11a is set to 100 to 150 μm and the thickness of the concave portion printing mask portion 16 is set to 100 to 150 μm. Further, even when the thickness of the concave portion printing mask portion 16 exceeds 150, if patterning of the mask of the screen mask is possible,
It can be expected that the above effects can be obtained by using this. With the current mask patterning technology, a mask thickness of 500 μm is possible, and this thickness is considered to be possible. As described above, by using the special screen mask of the present invention, it is possible to perform printing on concave portions of a printing target, which is not good at screen printing, and it is expected to develop into various application fields in the future.

[0015]

According to the screen printing method using the special screen mask of the present invention, it becomes possible to easily print the concave portion of the substrate having the concave portion, which is very difficult in the conventional screen printing, and the conventional method. As compared with tampon printing, which is a printing method, it is possible to manufacture thick coatings with good pattern accuracy at low cost.

[Brief description of drawings]

FIG. 1A is an explanatory diagram in the middle of printing showing an embodiment of a screen printing method of the present invention, and FIG. 1B is an explanatory diagram after printing by the printing method.

FIG. 2A is an explanatory diagram showing a conventional screen printing method during printing, and FIG. 2B is an explanatory diagram after the same printing.

[Explanation of symbols]

 11 printed matter 11a recess 12 Ag paste 13 squeegee rubber 14 mesh part 15 mask part 16 mask part for recess printing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Zenichi Tsuru 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A special screen mask having a concave portion printing mask portion, a concave portion outer peripheral portion forming mask portion, and a mesh portion on the bottom of the concave portion is used for a substrate having a concave portion, and the concave portion printing mask portion is provided inside the concave portion. A screen printing method in which the paste is embedded in the recesses and printed with squeegee rubber.