JP2710512B2 - Manufacturing method of printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for manufacturing a printed wiring board having a solder resist process.

[0002]

2. Description of the Related Art For forming a solder resist used for the purpose of preventing a solder bridge on a printed wiring board, a photographic method using a photosensitive liquid solder resist is used instead of a conventional screen printing method for a high density printed wiring board. Commonly used.

A method of manufacturing the solder resist process by the photographic method will be described with reference to FIG.

First, as shown in FIG. 2A, a circuit 1a is formed on an insulating substrate. Next, as shown in FIG. 2B, a photosensitive liquid solder resist is applied to the insulating substrate 1 on which the circuit is formed, and dried in a hot air circulating furnace to obtain a photosensitive solder resist film 2. Next, as shown in FIG. 2C, a mask film 4 having a predetermined pattern is superposed and positioned on the circuit-formed insulating substrate 1, and then exposed and exposed to form a solder resist film 5. Next, as shown in FIG. 2D, the solder resist film 6 in the unexposed portion is developed and removed to obtain a printed wiring board having the solder resist film 5 exposed between the circuits 1a.

[0005]

The conventional manufacturing method has the following problems.

In general, a photosensitive liquid solder resist contains low-molecular components such as a polymerization initiator and a sensitizer in its components for the purpose of imparting photosensitivity. For this reason, the dried photosensitive liquid solder resist film has adhesiveness even at room temperature. On the other hand, when the temperature exceeds 30 ° C., the tackiness tends to be extremely high.

[0007] Therefore, the photosensitive solder resist film after drying cannot contact or overlap with each other even at room temperature. 0.4m thick
The printed wiring board of m or less could not be manufactured because it was difficult to hold it upright.

If the temperature exceeds 30 ° C. during exposure,
Since the adhesiveness becomes remarkable and the exposed glass surface comes into close contact with the photosensitive solder resist film, transport failure occurs, quality defects occur in the photosensitive solder resist film, and production efficiency is deteriorated.

It is an object of the present invention to provide a method for manufacturing a printed wiring board which allows repeated handling of a photosensitive solder resist after drying and does not cause tackiness upon exposure.

[0010]

According to a method of manufacturing a printed wiring board of the present invention, a photosensitive liquid solder is applied to an insulating substrate on which a circuit is formed and dried to obtain a photosensitive solder resist film. A step of forming a release agent coating film by applying and drying a release agent on the solder resist film, and further, overlapping and exposing a mask film having a predetermined pattern to the unexposed portion of the photosensitive solder resist. Simultaneously developing and removing the film and the release agent coating film.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1E are cross-sectional views showing a sequence of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1A, a circuit 1a is formed on an insulating substrate.

Next, as shown in FIG. 1B, a photosensitive liquid solder resist is applied to the circuit-formed insulating substrate 1 to a thickness of 20 to 50 μm by a spray coater method.
The photosensitive solder resist film 2 is obtained by drying in a hot air circulating furnace at 00 ° C. for 10 to 30 minutes.

Next, as shown in FIG. 1C, a release agent is applied on the photosensitive solder resist film 2 to a thickness of 0.5 to 3 μm, and the release agent is applied in a hot air circulation furnace at 20 to 100 ° C. After drying for 10 minutes, the release agent coating film 3 is obtained.

Next, as shown in FIG. 1 (d), a mask film 4 having a predetermined pattern is superimposed and positioned on the insulating substrate 1 on which a circuit is formed, and 400 to 1000 mJ /
The exposed solder resist film 5 is obtained by irradiating and irradiating with ultraviolet energy of cm ² .

Next, as shown in FIG. 1 (e), the unexposed portion of the solder resist film 6 and the release agent coating film 3 are simultaneously coated by 0.5 to 0.5 μm.
Develop and remove with 3.0% aqueous sodium carbonate
The pattern of the solder resist film 5 exposed during the period a is formed, and a printed wiring board is obtained.

The release agent used is a mixture of a silicone resin mixed with a binder and dissolved in an organic solvent. A solution obtained by mixing a fluororesin with a binder and dissolving it in an organic solvent can also be used. The method of applying the release agent on the photosensitive solder resist film can also be performed by a method such as a spray coater method, a roller coater method, or a brush coating method.

The method of applying the photosensitive liquid solder resist to the circuit-formed insulating substrate includes screen printing,
It can also be carried out by a method such as a curtain coater method or a roller coater method.

[0020]

As described above, the present invention has the following effects by forming a release agent coating film on a photosensitive solder resist film.

Since the insulating substrates on which the circuits are formed after drying can be stacked, handling becomes easy, and a printed wiring board having a thickness of 0.4 mm or less can be manufactured.

Further, even when the temperature exceeds 30 ° C. at the time of exposure, no tackiness appears, so that the transportability at the time of exposure is stabilized and the production efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view shown in the order of steps for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a conventional method of manufacturing a printed wiring board in the order of steps illustrating the method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Insulated substrate with circuit formed 1a Circuit 2 Photosensitive solder resist film 3 Release agent coating 4 Mask film having a predetermined pattern 5 Exposed solder resist film 6 Unexposed solder resist film

Claims (1)

(57) [Claims] 1. A step of applying and drying a photosensitive liquid solder on an insulating substrate on which a circuit is formed to obtain a photosensitive solder resist film, and applying and drying a release agent over the photosensitive solder resist film. A step of forming a release agent coating film, and further, a step of overlapping and exposing a mask film having a predetermined pattern, and simultaneously developing and removing the unexposed portion of the photosensitive solder resist film and the release agent coating film. A method for manufacturing a printed wiring board, comprising: