JPS59175188A - Method of forming resist pattern - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming fine resist patterns, and more particularly to a method for economically mass producing high-resolution resist patterns useful for manufacturing finely fabricated products such as printed circuits.

Today, silk screen printing is the mainstream method for forming resist patterns for printed circuits, but with this method, the maximum resolution of the pattern obtained is a line width of 150~
Since the resist pattern is 200 μm, the reality is that it is becoming increasingly difficult to meet the demands for forming high-resolution resist patterns as patterns become increasingly thinner.

Accordingly, an object of the present invention is to provide a new method for economically mass producing high-resolution resist patterns useful for the fabrication of microfabricated products such as printed circuits.

Needless to say, a printing method is a pattern forming method that is excellent in economical mass production. Among the various printing methods, the cheapest and fastest method for plate making is the planographic printing method, and it is known that a printed pattern with a resolution of about 30 μm in line width can be easily obtained using this method. However, the printed pattern obtained by this method has a thickness of about 3 to 5 μm.
V film, which in many cases has a considerable number of holes such as pinholes and eyeholes, so its resist resistance is generally low, making it particularly unsuitable as a resist pattern for microfabrication such as printed circuits. It is thought that there is no such thing. However, the inventors have found through many experiments that even with the above-mentioned printed pattern, if it is heated appropriately, it becomes a continuous film in which the holes are removed without deforming the pattern itself. It has been found that the heat-treated printed pattern can be used as a resist pattern for fine processing such as printed circuits.

The present invention was completed based on this knowledge.

That is, the present invention includes a first step of forming a printed pattern on a substrate to be resist-processed by a lithographic printing method using a resist ink that can be cured by fat heat or active energy rays, and (b) printing on the substrate. a second step of removing holes such as pinholes and eyeholes contained in the pattern by heating the pattern under conditions that do not cause deformation or hardening; (C) a printed pattern on the substrate; The present invention relates to a method for forming a resist pattern comprising a third culm, in which the resist pattern of the substrate is formed by curing the resist pattern by heating or exposing to active energy rays.

The present invention will be specifically described below with reference to the drawings. In FIG. 1, (1) is a lithographic printing machine, and this printing machine forms a printing pattern (6) on a substrate (2). In this example, a thermosetting resist ink is used. This printed pattern (6) is then heated with an infrared heating device (3). The printing pattern (6) is the third a before heating.
As shown in the figure, pinhole (6a), eyehole (6a)
h), etc., but after heating, these holes are removed and the film becomes a continuous film, as shown in FIG. 3b. The printed pattern (6) becomes fluid when heated, and this fluidity results in a continuous film with holes removed; advantageously, in many cases, the printed pattern (6) 6) It is not resistant to culms that cause the pattern itself to collapse. The reason why such a favorable phenomenon occurs is not clear, but it is probably due to the fact that the printed pattern (6) is an extremely thin film. The heating should be performed at a temperature below the curing temperature of the printing ink and for a time sufficient to create the flow necessary for hole removal. Therefore, appropriate heating conditions differ mainly depending on the properties of the resist ink used, but those skilled in the art can easily set these conditions. (4) is a hot air heating device, and the printed pattern (6) is cured by this device.

FIG. 2 shows another embodiment of the present invention, in which a lithographic printing press (1) has two plate cylinders (1a),
It is a two-color machine with (1'a), and each of these two plate cylinders is equipped with a plate with the same pattern, and these two plates are synchronized with each other so that overprinting of the same pattern can be performed. ing. This overprinting is effective in removing holes such as pinholes and eyeholes. Further, instead of or in addition to this overprinting, it is also effective to embed the printing pattern using a blanket cylinder to remove holes. This crushing refers to pressing the printed pattern with a blanket cylinder that is not supplied with ink, and this is done by using a two-color machine or a four-color machine with at least one blanket cylinder separated from the plate cylinder. It can be carried out. In this example, since ultraviolet curable resist ink is used as the printing ink, the printing pattern (6) is heated by the infrared heating device (3) to remove holes such as pinholes and eyeholes, and then heated by the ultraviolet irradiation device (3). f (hardened with Fil.

In the above example, a roll-type rotary offset printing machine is used, but as long as the printing machine is a flat plate, other configurations do not matter; for example, it can be a sheet-fed type, direct printing You can use things such as molds. The plate to be installed in the printing machine may be any planographic plate, and may be either a wet planographic plate such as an aluminum plate whose surface has been roughened by mechanical polishing or anodizing, or a dry planographic plate such as a sheet with an ink-repellent silicone surface layer. Can be used. As the substrate (2), a rigid or flexible printed school board can be used.

The majority of printed circuit boards are metal coated laminates or sheets, typically m-stripe laminates or sheets. As the printing ink, any curable resist ink may be used, as long as it is curable by heat, ultraviolet rays, electron beams, etc., and is suitable for planographic printing. In the above example, an infrared heating device is used as a heating device for hole removal, but this device can be replaced with a hot air heating device. There is no limitation on the heating means for removing holes.

As described above, the method of the present invention makes it possible to economically mass-produce high-resolution resist patterns by using a planographic printing method instead of the silk screen printing method that has been commonly used in the past. Therefore, it has extremely high practical value, and the resist pattern formed by the method of the present invention can be used as an etching resist or a plating resist suitable for microfabrication such as printed circuits.

The present invention will be specifically explained below using Examples.

Examples 1 to 12 (1) Vehicle synthesis Vehicle A: A polyester resin obtained by a conventional method from 111 parts of dodecenyl succinic anhydride, 100 parts of hydrogenated bisphenol A, and an epoxy resin (manufactured by Dainippon Ink & Chemicals, Inc., [Evicron 1050J]). Polymerizable acrylic prepolymer (
Manufactured by Toagosei Kagaku Co., Ltd., “Hachironix M-8030J
), 41 parts of trimethylolpro-6-panediacrylate monooftate and 0.2 parts of hydroquinone monomethyl ether were added, and these
Vehicle 8 was obtained by homogeneous dissolution at 10'C.
Vehicle B 122 parts of dodecenyl succinic anhydride, 00 parts of hydrogenated bisphenol Al, and epoxy resin ([Evicron 1050J
) Trimethylolpropane diacrylate monobenzoate 130R, 44 parts of trimethylolpropane diacrylate monooctoate and 0.2 part of hydroquinone monomethyl ether were added to the total amount of polyester resin obtained from 40 parts by a conventional method, and these were heated at 110"C. Vehicle B was obtained by uniform dissolution.

Vehicle C: 55 parts of trimethylolpropane diacrylate monocaprylate, 45 parts of Neopolymer 120J (manufactured by Nippon Petrochemical, petroleum resin), and 0.5 parts of hydroquinone were placed in a reaction vessel, and air was blown into the reaction vessel at 110°C. Vehicle C, which was dissolved and viscous at room temperature, was obtained.

Vehicle D: 55 parts of trimethylolpropane diacrylate monocaprylate, 45 parts of Veracasite-1110J (Dainippon Ink Chemical Co., Ltd., natural resin-modified phenolic tree Mii)
1 part and 0.5 part of hydroquinone were placed in a reaction vessel and dissolved at 120°C without blowing air to obtain Vehicle D, which was viscous at room temperature.

Vehicle E Pentaerythritol triacrylate ester monolinseed oil fatty acid ester 35 parts, hydroquinone monomethyl ether 0.01 part, [Neopolymer 120 J 5
Vehicle E was obtained by dissolving 0 parts of DJ and 20 parts of [special turben] DJ at 120°C.

(2) Production of resist ink The formulations shown in Table 1 using the vehicle described above were sufficiently milled using three rolls to produce a resist ink.

Table 1 *1 Photosensitizer manufactured by Ciba Geigy *2 Pigment 9 manufactured by Dainippon Ink & Chemicals Co., Ltd. (3) Formation of resist pattern Form a resist pattern on a rigid printed circuit board or flexible printed circuit board using the above resist ink. Formed.

Various methods were used to form the pattern by combining the following steps. These are summarized in Table 2.

AI process; Test pattern for printed wiring (minimum line width 5
Printing process using a sheet-fed lithographic printing machine equipped with a wet lithographic printing plate (aluminum plate) with a printing area of 0 μm).

A2 process: Printing process using a sheet-fed lithographic printing machine equipped with a dry lithographic printing plate (having a silicone ink-repellent layer) having an image area with the same pattern as above.

B Process i A process of overprinting the same pattern using the same method after the A1 or A2 process.

C step: A step of performing blanketing after A1, A2 or B step.

Step D: A step of preheating the printed pattern using an infrared heating device. This device has a filament length of 75 cm.

It has four infrared lamps with an output of 3.75 KW, which are arranged in parallel rows with a spacing of 15 cIg from each other, so that they can heat the printed matter 1' O cm below.

10-E1 step; thermal curing step of the printed pattern using a hot air heating dryer. Heating temperature: 150℃.

E2 step; a step of curing the printed pattern using an ultraviolet irradiation device. This device has a focusing reflector, an emission length of 75σ, and an output of 6.
It has four OKW high-pressure mercury lamps, which are arranged in parallel with an interval of 15 cm from each other, so that they can irradiate the printed matter with light at a distance of 10 cm below the lamps.

E3 step; curing step of the printed pattern using an electron beam irradiation device. This device is of an electrocurtain type with an accelerating voltage of 175 KV and a current value of 10 mA.

Table 2 Board a: Hard copper-clad printed circuit board Board b; Flexible copper-clad printed circuit board (4) Evaluation The resist pattern was evaluated as follows.

Check with a magnifying glass whether there are any holes such as pin holes or eye holes before etching.

◎−−−−−−Not at all ○−−−−−−A few △−−−−−−Many x−−−−−A significant number of holes Presence or absence of holes after etching Ferric chloride etching solution After etching, check and evaluate as above.

Pattern reproducibility Check whether the pattern with the minimum line width (50 μm) is reproduced sharply according to the pixel after etching.
Confirmed using a Sigisop microscope (100x magnification).

a------One pixel line b------There is no line thinning, but there is a jagged pattern due to side etching.

c------There is a thin line d--------Pattern destruction The evaluation results for each side are shown in Table 3.

13- Table 3 14-

[Brief explanation of drawings]

1 and 2 are process explanatory diagrams of the method of the present invention, and FIG. 3 is a cross-sectional view of a resist pattern, showing changes in shape before and after heating. (]]1------~-lithographic printing ta (21-
-----1 board (31----1 infrared heating device
+4+ ------1 Hot air heating device (5) ---
--1 Ultraviolet irradiation device (61--1 Printing pattern agent Patent attorney Katsutoshi Takahashi 15
− Sword 3 figure ↓ 7>17 jiru

Claims (1)

[Scope of Claims] A first step of forming a printed pattern on a substrate to be resist-processed by a lithographic printing method using a resist ink that can be cured by heat or active energy rays; a second step of removing holes such as pinholes and eyeholes contained therein by not heating the material under conditions that do not cause deformation or hardening;
C1 A method for forming a resist pattern, comprising a third step of curing the printed pattern on the substrate by heating or exposing it to active energy rays. 2. The method according to claim 1, wherein the printing pattern is formed in the first step by overprinting the same pattern. 3. The method according to claim 1 or 2, wherein after the printing pattern is formed in the first step, the pattern is crushed by a blanket cylinder that does not receive ink supply. 48. The method according to claims 1 to 3, wherein the active energy ray is an ultraviolet ray or an electron beam.