JP4461847B2 - Mask film for exposure and method for producing printed wiring board using the same - Google Patents

Description

  The present invention relates to an exposure mask film used for electronic equipment or the like on which electronic components are mounted with high density, and a method for manufacturing a printed wiring board using the same.

  In general, the formation of a circuit pattern of a printed wiring board that requires a fine line and a narrow pitch is performed by a photographic process.

  A conventional method for manufacturing a printed wiring board will be described with reference to FIG.

  As shown in FIG. 9A, a photosensitive material 26 is formed on a copper clad laminate 27, and an exposure mask film 21 is placed on the photosensitive material 26 as shown in FIG. 9B. An acrylic plate 28 is stacked thereon and vacuum-adsorbed.

  Next, after exposure by irradiating with ultraviolet light V, an unexposed portion is dissolved and removed with a predetermined developer to obtain an etching resist 29 having a circuit pattern as shown in FIG.

  Thereafter, the exposed copper foil is etched, the etching resist 29 is removed, and a circuit pattern is obtained.

  In such a conventional method for manufacturing a printed wiring board, when foreign matter 30 is mixed between the exposure mask film 21 and the acrylic plate 28 during exposure with the ultraviolet light V, the foreign matter 30 blocks the ultraviolet light V. However, there is a problem that defects are generated in a required circuit pattern and the process yield is remarkably deteriorated.

  Conventionally, in order to solve this problem, as shown in FIG. 10, a diffusion film 22 is formed on the upper surface of an exposure mask film 21, and a photosensitive material 26 formed on a copper clad laminate 27 via the diffusion film 22. A method of manufacturing a printed wiring board was conceived by a step of exposing the substrate to ultraviolet light for exposure.

  This is because the irradiated ultraviolet light diffuses inside the diffusion film 22, and even if there is a foreign material 30 between the acrylic plate 28 and the diffusion film 22, the light wraps directly under the foreign material. That is, the etching resist 29 having a required pattern can be obtained without being shielded from light by the foreign matter 30.

For example, Patent Document 1 is known as prior art document information related to the invention of this application.
JP-A-3-256393

  However, as shown in FIG. 10 (a), the incident ultraviolet light V is diffused when it reaches the photosensitive material 26. As a result, after development, as shown in FIG. 10 (b), line thickening occurs, The resolution of the etching resist 29 is lowered.

  In particular, in a printed wiring board that requires a thin line of a circuit pattern and a narrow pitch between lines, a reduction in resolution has been a big problem.

  The present invention solves this problem. Even if foreign matter is present on the mask film for exposure, the printed wiring board having excellent reliability can be obtained with a very high process yield without degrading the resolution in the exposure process. It is intended to provide.

  In order to achieve the above object, the present invention provides an exposure mask film having a condensing film and a mask film having a mask pattern below the light diffusing layer, or a condensing property having a mask pattern immediately below the light diffusing layer. An exposure mask film having a film is used, and the photosensitive material formed on the substrate is irradiated with ultraviolet light through the mask film for exposure.

  Thereby, the incident ultraviolet light is diffused at the stage of reaching the surface of the photosensitive material by being condensed when it is diffused by the diffusion layer and then transmitted through the light collecting film. As a result, it has the effect of avoiding the influence of foreign matter on the exposure mask film and maintaining the resolution in the exposure process.

  In addition, the mask film is protected by attaching the condensing film to the surface on which the mask pattern of the mask film is drawn, and the exposure is performed by condensing the diffused ultraviolet light when passing through the condensing film. It has the effect | action that the resolution in a process can be maintained.

  Furthermore, by providing a mask film directly under the light diffusion layer, the light diffusion layer and the mask film can be integrated, and the exposure mask film of the present invention can be easily produced.

In addition, by diffusing the light in the light diffusion layer and condensing the light collecting film, the ultraviolet light incident on the exposure mask film is diffused in the light diffusion layer through the light collecting film. By condensing, it is possible to approach a state equal to the incident angle when reaching the photosensitive material. As a result, it has the effect that the resolution in the exposure process can be maintained.
In addition, the light diffusion layer and the condensing film can be reversed with each other using the same material, and an exposure mask film can be easily produced.

  By manufacturing a printed wiring board characterized by irradiating the photosensitive material formed on the substrate through the exposure mask film of the present invention by irradiating ultraviolet light, even if foreign matter exists on the mask film Thus, it is possible to provide a printed wiring board excellent in reliability at a very high process yield without degrading the resolution in the exposure process.

  In short, the configuration of the present invention diffuses ultraviolet light incident on the mask film for exposure at the stage of reaching the surface of the photosensitive material by diffusing the diffusion layer through the diffusion layer and condensing the light when passing through the condensing film. It is to suppress.

  Thereby, even if a foreign material exists on the mask film for exposure, this invention can provide the printed wiring board excellent in reliability with a very high process yield, without reducing the resolution in an exposure process. .

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment)
1-5 is sectional drawing which shows the structure of the mask film for exposure in embodiment of this invention.

  The exposure mask film 1 has a configuration in which a light diffusion layer 2, a condensing film 3 immediately below the uppermost layer, and a mask film 4 on which a mask pattern is drawn are further stacked in three layers. The light diffusing layer 2, the condensing film 3, and the mask film 4 are made of a material that can transmit ultraviolet light suitable for curing of the photosensitive material.

  The light diffusion layer 2 has a function of diffusing ultraviolet light emitted from the light source of the exposure apparatus.

  The light diffusion layer 2 can also be formed by applying spherical fine particles or the like on the surface of the light collecting film 3, but the exposure mask film 1 can be easily prepared by using a sheet-like diffusion film. It becomes. In the present embodiment, a diffusion film is employed as the light diffusion layer 2.

  The condensing film 3 has a function of condensing the ultraviolet light diffused by the light diffusion layer 2.

  Moreover, the condensing film 3 can use the same quality material as a diffusion film, and can be reversed and used. FIG. 2 shows an exposure mask film having such a configuration.

  As an advantage of this configuration, the degree of light diffusion of the light diffusion layer 2 and the degree of light collection of the light collecting film 3 can be made equal. As a result, the ultraviolet light diffused in the light diffusion layer 2 can approach the state where the angle reaching the photosensitive material is equal to the incident angle through the condensing film 3, and the resolution can be improved. .

  Moreover, as shown in FIG. 3, it is also possible to set it as the exposure mask film which has arrange | positioned the condensing film 3 in the state which coat | covered the mask pattern 5 directly under the mask film 4. FIG.

  As an advantage of this configuration, in addition to improving the resolution, the mask pattern 5 is protected, and the occurrence of scratches on the mask pattern 5 that causes problems such as disconnection of the circuit pattern of the printed wiring board is prevented. it can.

  Moreover, as shown in FIG. 4, it is also possible to set it as the exposure mask film which has arrange | positioned the mask film 4a which has condensing property directly under the light-diffusion layer 2. FIG. The mask film 4a has a mask pattern 5 drawn on it, and has a light condensing property. The ultraviolet light diffused by the light diffusion layer 2 is incident at an angle reaching the photosensitive material through the mask film 4a. It is possible to approach a state equal to the measured angle, and the resolution can be improved.

  Further, the exposure mask film can be easily created by integrating the light diffusion layer and the mask film as a base material for the exposure mask film and drawing the mask pattern 5 thereon.

  In addition, as shown in FIG. 5, the light diffusion layer and the mask film can be reversed with each other using the same material. In this configuration, since the degree of light diffusion of the light diffusion layer 2 and the degree of condensing of the mask film 4a are equal, the ultraviolet light incident on the exposure mask film has an incident angle when reaching the photosensitive material. It is possible to approach the same state, and the resolution can be improved. Moreover, the mask film for exposure can be easily created as in the case of FIG.

  Next, the manufacturing method of the printed wiring board using the mask film for exposure of this invention is demonstrated.

  FIG. 6 is a cross-sectional view showing a method for manufacturing a printed wiring board using the exposure mask film in the embodiment of the present invention.

  As shown in FIG. 6A, an exposure mask film 1 is positioned on a copper-clad laminate 7 on which a photosensitive material 6 is formed, an acrylic plate 8 is placed thereon, and the photosensitive material is vacuum-adsorbed. 6 and the mask film 1 for exposure are adhered.

  Next, as shown in FIG. 6B, the photosensitive material 6 is exposed to ultraviolet light emitted from an exposure light source (not shown) through the acrylic plate 8 and the exposure mask film 1. The exposure dose to be irradiated is set in consideration of the appropriate exposure dose of the photosensitive material 6 and the transmittance of the exposure mask film.

  Thereafter, the unexposed portion is removed with a developing solution to form an etching resist 9 having no line thickness as shown in FIG.

  Next, the mechanism in the case where foreign matter exists on the exposure mask film will be described.

  FIG. 7 is a cross-sectional view showing a method for manufacturing a printed wiring board using the exposure mask film shown in FIG.

  The arrows in FIG. 7 indicate the ultraviolet light incident path. The incident ultraviolet light V is diffused by the light diffusion layer 2 to avoid the influence of the foreign material 10 on the exposure mask film 1, and the diffused ultraviolet light is collected when passing through the light collecting film 3. 2 shows a state of entering the photosensitive material 6.

  FIG. 8 is a cross-sectional view showing a method of manufacturing a printed wiring board using the exposure mask film shown in FIG.

  As indicated by the arrows in the figure, the incident ultraviolet light V is diffused in the light diffusion layer 2 to avoid the influence of the foreign matter 10 on the mask film for exposure 1 and pass through the mask film 4a. A state in which diffused ultraviolet light is collected and incident on the photosensitive material 6 is shown.

  7 and 8, the ultraviolet light V incident on the exposure mask film 1 is diffused by the light diffusion layer 2 and condensed through the condensing film 3 or the mask film 4a to reach the photosensitive material 6. In this case, it is shown that the angle is close to the incident angle.

  From the above, the printed wiring board manufacturing method using the exposure mask film of the present invention has a remarkable effect of avoiding the influence of the foreign material 10 and maintaining the resolution in the exposure process.

  As described above, according to the configuration of the present invention, even if foreign matter is present on the exposure mask film, a highly reliable printed wiring board having an extremely high reliability can be obtained without degrading the resolution in the exposure process. It can be provided with a yield, and the industrial applicability is great.

Sectional drawing which shows the mask film for exposure in embodiment of this invention Sectional drawing which shows the mask film for exposure in the same embodiment Sectional drawing which shows the mask film for exposure in the same embodiment Sectional drawing which shows the mask film for exposure in the same embodiment Sectional drawing which shows the mask film for exposure in the same embodiment Sectional drawing which shows the manufacturing method of the printed wiring board in the embodiment Sectional drawing which shows the manufacturing method of the printed wiring board in the embodiment Sectional drawing which shows the manufacturing method of the printed wiring board in the embodiment Sectional drawing which shows the manufacturing method of the conventional printed wiring board Sectional drawing which shows the manufacturing method of the conventional printed wiring board

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mask film for exposure 2 Light diffusion layer 3 Condensing film 4, 4a Mask film 5 Mask pattern 6 Photosensitive material 7 Copper-clad laminated board 8 Acrylic board 9 Etching resist 10 Foreign material

Claims (4)

A light diffusing layer is laminated on the uppermost layer, a light condensing film directly below the light diffusing layer, and a mask film on which a mask pattern is drawn directly below the light diffusing layer. An exposure mask film characterized in that the degree of condensing is equal. The light diffusing layer is a diffusing film, the condensing film is made of the same material as the diffusing film, and the diffusing film and the condensing film are reversed and laminated. The mask film for exposure as described. An exposure mask film comprising: a light diffusing layer as an uppermost layer; and a mask film having a mask pattern drawn immediately below the light diffusion layer, and a condensing film disposed in a state of covering the mask pattern. A method for producing a printed wiring board, comprising exposing a photosensitive material formed on a substrate through the exposure mask film according to claim 1 by irradiating with ultraviolet light.

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