JP2017187648A - Manufacturing method of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a wiring board capable of preventing abnormality of a finally formed wiring due to recess generated on a surface of a resist layer by a lubricant contained in a supporter film and solving yield aggravation of the wiring substrate.SOLUTION: A protective film 3 in a dry film consisting of 3-layer structure of a protective film (not shown in the Figure), a resist layer 2 and a supporting film 3 containing a lubricant 4 projecting on a surface is peeled and the resist layer 2 is formed on a conductive metal layer 1 with a laminator 6, the supporting film 3 with the lubricant 4 projecting on the surface on the resist layer 2 is peeled, the surface of the resist layer 2 is flatted, a resin film 5 with a flat surface is laminated and then light is radiated with a predetermined pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a wiring board.

Conventionally, in a method for manufacturing a printed circuit board or the like, a resist film (also referred to as a dry film) composed of three layers in which a photosensitive resist is sandwiched between a protective film and a support film is used. Specifically, the photosensitive resist (resist layer) is vacuum laminated on a composite material in which a conductive metal layer is provided on the surface of an insulating substrate while peeling off a protective film provided on the resist film, thereby insulating the resist film. A photosensitive resist is in close contact with a conductive metal layer of a composite material composed of a base material and a conductive metal layer, and a support film is further laminated thereon.
Then, the photosensitive resist is exposed to a predetermined pattern by the exposure device, the photosensitive resist in the unexposed portion is removed by the developing device, and a resist mask is formed.
Next, the conductive metal layer exposed from the resist mask is dissolved and removed by an etching method to form a wiring, or the exposed conductive metal layer is generally plated to form a wiring.

At present, in the wiring board, the width of the wiring to be formed is becoming very narrow with the high integration, and those having a size of 10 μm or less are mass-produced and many are being produced in the world.
Along with the thinning of the wiring width, a slight defect of the resist mask formed with a photosensitive resist causes a defect in the formed wiring and greatly affects the manufacturing yield.

However, metal wiring patterns such as printed wiring boards with less defects such as chipping, disconnection, and shorting of wiring formed in the etching process or plating process derived from the resist mask sidewall shakiness after development are small. An exposure method in the manufacturing process is disclosed in the following Patent Document 1.
In the exposure method described in Patent Document 1, the photosensitive resin layer is adhered to the metal-coated surface of the metal-coated insulating plate while peeling off the protective layer of the photosensitive resin laminate having the support, the photosensitive resin layer, and the protective layer. In the exposure, the support is peeled off before the exposure, and the image of the photomask is projected through the lens.

JP 2003-66625 A

  At present, in a dry film that is generally used, the support film contains a lubricant having a size of about 0.1 to 5.0 μm, and this lubricant has a minute bump (projection) on the surface of the support film. As a result, this bump forms a depression (recess) that is transferred to the surface of the resist layer, and the position of this depression is at the boundary between exposure and non-exposure in the exposure process. In such a case, the exposure light interference occurs, the trace at the boundary is not accurately performed, a defect occurs in the resist mask to be formed, and the wiring formed using the resist mask has a wiring defect as a result. As a result, defects will be created, and it has become impossible to overlook the recent thinning.

  However, in the technique disclosed in Patent Document 1, there is a recess in which the same shape is transferred to the surface of the resist layer by the protrusion of the lubricant protruding on the surface of the support film, and this recess is exposed during exposure. Refraction of light is caused, a defect is generated in the resist mask, and the wiring formed by the resist mask becomes abnormal.

  The present invention has been made in view of the above problems, and by using the lubricant contained in the support film, it is possible to prevent the abnormality of the wiring finally formed due to the concave portion generated on the surface of the resist layer, and It is an object of the present invention to provide a method of manufacturing a wiring board capable of eliminating the yield deterioration.

  In order to achieve the above-described object, a method of manufacturing a wiring board according to the present invention includes a protective film, a resist layer, and a dry film comprising a three-layer structure of a support film containing a lubricant and having a lubricant protruding on the surface. A protective film is peeled off, a resist layer is formed on the conductive metal layer by a laminator, a support film with a lubricant protruding on the surface is peeled off, and the surface of the resist layer is flattened. Is characterized in that after applying a smooth resin film, exposure is performed in a predetermined pattern.

  Also, the method for manufacturing a wiring board according to the present invention includes a protective film, a resist layer, a lubricant, and a laminator by peeling off the protective film provided on a dry film having a three-layer structure of a support film having a lubricant protruding on the surface. After forming a resist layer on the conductive metal layer, peeling off the support film provided with the lubricant on the surface provided on the resist layer, and planarizing the surface of the resist layer with a smooth surface roller, The exposure is performed in a predetermined pattern.

  According to the present invention, a resist mask having no defect after exposure / development is formed by smoothing the surface of the resist layer. Therefore, the wiring formed using the resist mask is also formed without any defect. Therefore, it is possible to eliminate the deterioration of the yield of the wiring board.

It is explanatory drawing which shows typically the principal part process in the manufacturing method of the wiring board of this invention. It is a photograph which shows a SEM image when the state (resist mask) after exposure and development of the resist layer which processed with the manufacturing method of the wiring board which concerns on one Example of this invention is observed. It is a photograph which shows the SEM image when observing the state (resist mask) after exposure and image development of the resist layer processed with the manufacturing method of the conventional wiring board based on the comparative example of this invention.

The method for producing a wiring board of the present invention comprises a three-layer structure of a support film that contains a protective film, a resist layer, and a lubricant, and has a lubricant protruding on the surface, in the step of attaching a dry film onto the conductive metal layer. The protective film (not shown) provided on the dry film is peeled off, and immediately after the resist layer 2 is applied onto the conductive metal layer of the wiring board 1 as shown in FIG. A continuous process is used in which the support film 3 from which the lubricant 4 protrudes is peeled off, and then the surface of the resist layer 2 is flattened by laminating the resin film 5 having a smooth surface on the resist layer 2 within a few seconds. In FIG. 1, 2a is a dry film having a three-layer structure, and concave portions formed on the surface of the resist layer 2 by a number of minute bumps formed on the surface of the support film 3 by the lubricant 4, and 6 is a smooth surface. It is a laminating roller for laminating a transparent resin film 5 on the resist layer 2.
The resin film 5 having a smooth surface to be laminated on the resist layer 2 has at least the smoothness of the surface on the side of the resist layer 2 to be bonded, the wiring width of the wiring pattern to be finally formed, the width between the wirings, and products required for them. Although it depends on the standard, it is generally desirable that the surface roughness is Rmax <minimum wiring width (or minimum wiring width) / 3 at most.
More preferably, it is desirable to use a highly transparent resin film for the resin film 5 having a smooth surface.
As an example of a highly transparent resin film desired to be used as the resin film 5 having a smooth surface, Toyobo Co., Ltd., product name Cosmo Shine, model number A4100, thickness 50 μm, Toyobo Co., Ltd., product name Cosmo Shine Model number A4300, thickness 38 μm, and the like.
As for the conditions for laminating the resist layer 2 and the resin film 5 having a smooth surface, a pressure of 0.1 to 5.0 kg / cm and a temperature of 20 to 130 ° C. are preferably required. It is desirable to laminate at a rate of / min.
Moreover, it is desirable to use a vacuum laminator apparatus in order to avoid the generation | occurrence | production of the wiring defect by a particle | grain in a series of processes, such as lamination of the resist layer 2, peeling of the support film 3, and lamination of the resin film 5 with the smooth surface.
Moreover, the manufacturing method of the wiring board of this invention does not laminate | stack the resin film 5 with a smooth surface on the surface of the resist layer 2 which peeled the support film 3, but the surface of the resist layer 2 with the roller with a smooth surface. You may planarize.

The protective film, the resist layer, and the protective film provided on the dry film consisting of the three-layer structure of the support film that contains the lubricant and the surface of the lubricant are peeled off. And it laminated on the flexible substrate which has the electroconductive metal layer which sputter | spatterd chromium and gave copper plating thinly by the reel-to-reel system.
Within several seconds after lamination, the coating support film with the lubricant protruding on the surface thereof was peeled off within a few seconds, and a resin film with a smooth surface was laminated within a few seconds after peeling.
In this example, a resin film made of PET was used.
The dry film laminating conditions were a temperature of 105 ° C. and a pressure of 2 kg / cm, and the resin film laminating conditions were a temperature of 40 ° C. and a pressure of 2 kg / cm.
Next, the smooth resin film was peeled off from the laminate of the flexible substrate, the dry film, and the smooth resin film, and then exposed and developed to remove unnecessary portions of the resist layer, thereby forming a resist layer pattern.
FIG. 2 shows the state of a resist mask formed so as to eliminate the occurrence of minute wiring defects by the wiring board manufacturing method of this embodiment.
FIG. 2 is a photograph showing an SEM image when the state after development of the resist layer processed by the wiring board manufacturing method of this example is observed.
As shown in the photograph of FIG. 2, a defect of about several μm could not be confirmed on the sidewall of the resist layer.

As a comparative example, a resist mask was manufactured through a conventional process. That is, as in the present example, a dry film resist from which a protective film, a resist layer, and a dry film comprising a three-layer structure of a support film containing a lubricant and having a lubricant projecting on the surface is peeled off. After laminating the dry film side of the laminate of the dry film and the support film on the flexible substrate to the flexible substrate on the flexible substrate, the support film is peeled off and a smooth resin film is laminated as in this example. Then, exposure and development were performed to form a resist layer pattern.
FIG. 3 shows the situation of minute wiring defects found in the resist mask formed by the wiring board manufacturing method of the comparative example.
FIG. 3 is a photograph showing an SEM image when the resist layer processed by the conventional method for manufacturing a wiring board according to a comparative example of the present invention is observed after exposure and development.
Originally, the pattern shape of the resist layer should match the pattern shape of the photomask, and there should be no recesses on the surface and side surfaces of the resist layer, but the resist mask was manufactured by the method of manufacturing a wiring board of the comparative example. In this case, as shown in the photograph of FIG. 3, holes were formed on the surface of the resist layer, and defects such as a large number of vertical stripe patterns and wiring deformation occurred on the sidewalls.

DESCRIPTION OF SYMBOLS 1 Wiring board 2 Resist layer 2a Recess 3 Support film 4 Lubricant 5 Smooth surface (resin) film 6 Laminating roller

Claims (2)

  A protective film, a resist layer, and a support film containing a lubricant and a support film having a lubricant projecting on the surface are peeled off and the protective film provided on the dry film is peeled off, and a resist layer is formed on the conductive metal layer by a laminator. After forming and peeling off the support film with the lubricant protruding on the surface provided on the resist layer, flattening the surface of the resist layer, applying a smooth surface resin film, and then exposing in a predetermined pattern A method for manufacturing a wiring board, comprising:   A protective film, a resist layer, and a lubricant are contained, and the protective film provided on the dry film having a three-layer structure of the supporting film having a lubricant protruding on the surface is peeled off, and a resist layer is formed on the conductive metal layer by a laminator. The wiring provided on the resist layer, the support film having a lubricant projecting on the surface is peeled off, the surface of the resist layer is flattened by a roller having a smooth surface, and then exposed in a predetermined pattern. A method for manufacturing a substrate.