JPS6159447A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To improve the photosensitivity of a photosensitive resin composition and to increase the thermal shock resistance by using half-ester obtd. by converting part of epoxy in a novolak type epoxy compound into acrylate as a base material. CONSTITUTION:A photosensitive resin composition is prepd. by blending 21.2wt% phenol novolak half-ester as a base material with 10.6wt% trimethylolpropane triacrylate as a diluent, 14.7wt% polyester diacrylate and 18.4wt% hydroxyethyl acrylate. To the resin composition are added 1.8wt% mixture consisting of bismethacryloxyethyl phosphate and methacryloxyethyl phosphate for improving the adhesive property to copper foil, 2.4wt% photosetting accelerator, 0.2wt% colorant and 30.7wt% talc as a filler.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive resin composition used, for example, as a solder resist in printed wiring boards.

[Conventional technology]

It is known that photosensitive resin compositions have been used as solder resists conventionally used in printed wiring boards, and that they are formed by photographic methods. As this photosensitive resin composition, for example, acrylic ester resin is known.

[Problem that the invention seeks to solve]

Acrylic acid ester resin has excellent photosensitivity, that is, photopolymerizability, but has a problem with heat resistance and cannot be used with solder levelers (
For example, 230-260℃ for 5 seconds), reflow oven (for example, max. 260℃ for 10 seconds), solder dip (for example, 260℃ for 10 seconds),
There is a drawback that the resin on the copper foil pattern becomes blistered due to a decrease in adhesion in response to a thermal shock such as 0 seconds).

[Failure to solve the problem]

In order to solve the above-mentioned problems, the present invention uses Hafestel as a base material, which is obtained by converting a part of the epoxy group of Novola 7-type epoxy into acrylate.

[Effect]

In the above composition, the epoxy group contributes to heat resistance, and the acrylic group contributes to photopolymerizability, so it is possible to obtain a product that has excellent photosensitivity and can withstand thermal shock from solder levelers, reflow, solder dip, etc. can.

〔Example〕

An embodiment of the present invention will be described below.

Table 1 shows the composition of one example.

First, as a base material, we use Hafestel, in which a part of the epoxy group of novolac type epoxy is acrylated, for example, Hafestel, in which the ratio of epoxy groups and acrylic groups is approximately equal to each other, such as phenol novolac Hafestel (U1 product name Showa 21.2% by weight of polymers were used. Further, as a diluent, 10.6% by weight of trimethylolpropane triacrylate, such as TMPTA (trade name: Showa Kobunshi Co., Ltd.), 14.7% by weight of polyester diacrylate, such as MAND^ (trade name: Nippon Kayaku Layer), Then, 18.4% by weight of hydroxyethyl acrylate, such as HEA (trade name: Osaka Organic Type), is used.

Further, in order to improve adhesion to the copper foil, 1.8% by weight of a mixture of bismethacryloxyethyl phosphate and methacryloxyethyl bosphate, such as KAYAMERP 2 (trade name: Nippon Kayaku Layer), is used. In addition, 2.4% by weight of Irugacure 651 (trade name, manufactured by Ciba Geigy) is used as a photocuring accelerator. In addition, as a coloring agent, Ieliogen Green l, 873
0 (trade name: manufactured by BASF) is used in an amount of 0.2% by weight. Further, 30.7% by weight of Fine Talc P-3 (trade name, manufactured by Nippon Talc) was used as a filler.

Next, a method for forming a solder resist using the photosensitive resin composition of this example will be described with reference to FIG.

■ First, as shown in Figure A, the composition f1. ) are sequentially stirred and mixed, and finally thoroughly kneaded using three rolls.

■ Next, as shown in Figure B, the composition (1) is applied at a rate of, for example, 60/rm on the substrate (3) on which the copper foil (2) is selectively left.
Apply it to the front so that it has a thickness of .

■Next, as shown in FIG. 5)
Fill the photomask (4) with nitrogen gas N2.
A more ultraviolet parallel energy beam (6), for example 45
Irradiate mJ/c+a.

■ Next, as shown in the same figure, the exposed substrate (3) is placed in a developer solution (7) containing a surfactant and caustic soda.
For example, develop using a brush (8) for 1 minute, wash with water,
Perform drying.

■ Next, as shown in figure E, for example, 100W/cm
Three metal halide lamps (9) pass through the bottom 15c+n on a belt conveyor α0) at a speed of 6 m/min to perform ultraviolet curing.

(2) Finally, as shown in Figure F, final curing is performed by heating for 20 minutes in an oven (11) at 170°C, for example.

In addition, in the case of a double-sided board, turn it over and repeat steps ① to ②.

The substrate (3) on which a solder resist was formed using the composition using Hafestel as a base material of this example was subjected to a solder leveler for 3 seconds at 230°C, and a solder flow furnace for 10 seconds at a maximum temperature of 260°C. Through, another 26
Although it was passed through a solder dip layer at 0°C for 10 seconds, no "blister" or "peeling" occurred. Table 2 shows the experimental results, and compared them with a board in which a solder resist was formed using a composition based on a total ester in which all the epoxy groups of novolac type epoxy were acrylated. This is what is shown.

Table 2 In this case, "peeling" was determined by a tape cut test.

Fig. 2 shows an apparatus for measuring the adhesion of solder resist, in which (12) is a hot plate, (13) is a board with copper foil (14), (15) is a tension meter, and (16) is, for example, This is an ultraviolet transmitting chip made of Pyrex glass (registered trademark) or the like. The degree of adhesion of the solder resist is measured as follows.

■ First, as shown in Figure 2, a photosensitive resin composition (1
7) as an adhesive between the copper foil (14) of the substrate (13) and the chip (16), as shown in Figure 3.
6) Exposure and curing with ultraviolet light (18).

■ Next, change the temperature of the hot plate (12) step by step, and
The strength with which the chip (16) is sheared from the copper foil (14) in the state shown in the figure is measured using a tension meter (15).

Figure 4 shows the adhesion of the solder resist using the composition using Hafestel as the base material of this example and the solder resist using the composition using total ester as the base material through such measurements. This shows the results. In the figure, the solid line a represents the case of this example, and the solid line a represents the case of all esters. As is clear from FIG. 4, this example shows superior adhesion even in high temperature areas.

As described above, the photosensitive resin composition of this example has excellent photosensitivity and heat resistance.

In addition to the embodiments mentioned in -F, it is conceivable to use an epoxy-based Hafestel as shown in Table 3 as the base material.

〔Effect of the invention〕

As described above, according to the photosensitive resin composition of the present invention, a part of the epoxy group of novolac type epoxy is acrylated, and the epoxy group contributes to heat resistance.
Since the acrylic group is highly photopolymerizable, it is possible to obtain products with excellent photosensitivity and heat resistance. Therefore, it is suitable for use as a solder resist.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a solder resist forming process using an embodiment of the present invention, Fig. 2 is a solder resist adhesion measuring device, Fig. 3 is an explanatory diagram, and Fig. 4 is a diagram of the book. It is a figure which shows the measurement result of the degree of adhesion of solder resist I. using one Example of this invention. (1) is a photosensitive resin composition. 1 JP-A-6L-59447 (6) 1 (huge; . 5 o o <) o
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Claims (1)

[Claims] A photosensitive resin composition whose base material is a half ester in which a part of the epoxy group of a novolac type epoxy is acrylated.