Abstract: A printed wiring board includes a base insulating layer, a conductor layer formed on the base layer and including conductor pads, an underlayer formed on one of the conductor pads and including a metal different from a metal of the conductor layer, a solder resist layer formed on the base layer such that the solder resist layer is covering the conductor layer and has openings exposing the conductor pads, and a bump formed directly on a first conductor pad of the conductor pads and including a base plating layer formed in a first opening of the openings and a top plating layer formed on the base plating layer such that a metal of the base plating layer is same as the metal of the conductor layer. The conductor pads include a second conductor pad such that the second conductor pad is the one of the conductor pads having the underlayer.

Abstract: A printed wiring board includes a resin insulating layer including resin and particles, and a conductor layer formed on a surface of the resin insulating layer. The particles in the resin insulating layer include first particles and second particles such that the first particles are partially embedded in the resin and the second particles are completely embedded in the resin, and the resin insulating layer is formed such that the first particles has exposed surfaces exposed from the resin and covered surfaces covered by the resin, respectively, the surface of the resin insulating layer includes the first exposed surfaces, and a ratio of a second area to a first area is in a range of 0.1 to 0.25 where the first area is an area of the surface of the resin insulating layer, and the second area is obtained by summing areas of the exposed surfaces of the first particles.

Abstract: A printed wiring board includes a base insulating layer, a conductor layer formed on the base insulating layer and including conductor pads, an underlayer formed on one of the conductor pads of the conductor layer and including a metal different from a metal of the conductor layer, a solder resist layer formed on the base insulating layer such that the solder resist layer is covering the conductor layer and has openings exposing the conductor pads, respectively, and a bump formed directly on a first conductor pad of the conductor pads and including a base plating layer formed in a first opening of the openings and a top plating layer formed on the base plating layer such that a metal of the base plating layer is same as the metal of the conductor layer.

Abstract: A printed wiring board includes a base insulating layer, a conductor layer formed on the base layer and including conductor pads, an underlayer formed on one of the conductor pads and including a metal different from a metal of the conductor layer, a solder resist layer formed on the base layer such that the solder resist layer is covering the conductor layer and has openings exposing the conductor pads, and a bump formed directly on a first conductor pad of the conductor pads and including a base plating layer formed in a first opening of the openings and a top plating layer formed on the base plating layer such that a metal of the base plating layer is same as the metal of the conductor layer. The conductor pads include a second conductor pad such that the second conductor pad is the one of the conductor pads having the underlayer.

Abstract: A printed wiring board includes a base insulating layer, a conductor layer formed on the base insulating layer and including conductor pads, an underlayer formed on one of the conductor pads of the conductor layer and including a metal different from a metal of the conductor layer, a solder resist layer formed on the base insulating layer such that the solder resist layer is covering the conductor layer and has openings exposing the conductor pads, respectively, and a bump formed directly on a first conductor pad of the conductor pads and including a base plating layer formed in a first opening of the openings and a top plating layer formed on the base plating layer such that a metal of the base plating layer is same as the metal of the conductor layer.

Abstract: A method of manufacturing a printed wiring board with solder bumps includes forming a solder-resist layer having small and large apertures exposing a respective conductive pad of the printed wiring board, loading a solder ball in each of the small and large apertures using a mask with aperture areas corresponding to the apertures of the solder-resist layer, forming a first bump having a first height, from the solder ball in the small aperture, and a second bump having a second height, from the solder ball in the large aperture, the first height being greater than the second height, and pressing a top of the first bump such that the first height becomes substantially the same as the second height. A multilayer printed wiring board includes a solder-resist layer with apertures of differing sizes and solder bumps having substantially equal volumes but a difference in height no greater than 10 ?m.

Abstract: A printed wiring board includes a base insulating layer including an insulating material, a conductor layer formed on the base insulating layer and including conductor pads, a coating insulating layer formed on the base insulating layer such that the coating insulating layer is covering the conductor layer and having opening portions exposing the conductor pads, respectively, and bumps formed on the conductor pads respectively such that each of the bumps includes an electroless plating metal layer formed on a respective one of the conductor pads and a solder layer formed on the electroless plating metal layer, the electroless plating metal layer having an upper end surface formed such that a central portion of the upper end surface is recessed relative to a peripheral portion of the upper end surface.

Abstract: A method for manufacturing a printed wiring board includes clamping a mask device at clamping portioned formed in the mask device with a movable clamp device to apply tensile force to the mask device, positioning the mask device over a printed wiring board having connection pads, applying the tensile force to the mask device through the clamping portions such that a mask of the mask device undergoes elastic deformation and positions of opening portions in the mask are vertically aligned relative to positions of the connection pads of the printed wiring board, and loading solder balls through the opening portions in the mask onto the connection pads of the printed wiring board, respectively.

Abstract: A method for manufacturing a printed wiring board including providing a structure having a wiring substrate having a conductor circuit, a build-up multilayer structure formed over the wiring substrate and having an outermost conductor circuit and an outermost insulative resin layer, and a solder resist layer formed over the outermost conductor circuit and outermost insulative resin layer and having openings with an opening diameter D for mounting electronic elements, forming conductor pads with a pitch of about 200 pm or less on the outermost conductor circuit in the openings of the solder resist layer, respectively, and forming solder bumps with a height H from a surface of the solder resist layer on the conductor pads on the conductor pads, respectively, such that a ratio H/D is about 0.55 to about 1.0.

Abstract: A printed wiring board including a wiring substrate provided with at least one conductor circuit, a solder resist layer provided on the surface of the wiring substrate, at least one conductor pad formed from a part of the conductor circuit exposed from an opening provided in the solder resist layer, and at least one solder bump for mounting electronic parts on the conductor pad. In the printed wiring board, since the at least one conductor pad is aligned at a pitch of about 200 ?m or less, and a ratio (W/D) of a diameter W of the solder bump to an opening diameter D of the opening formed in the solder resist layer is about 1.05 to about 1.7, connection reliability and insulation reliability can be easily improved.

Abstract: A solder ball loading method capable of securely loading solder balls on connection pads includes applying flux on each connection pad group of a printed wiring board flux is not applied to a contact portion between a spacer and the printed wiring board to keep the flux from attaching to the spacer. Because the flux is not attached to the spacer, when the mask is detached from the printed wiring board, the printed wiring board need not be inverted, and damage to the solder resist layer 70 is minimized. Further, the heights of the solder balls and the upper surface of the mask are made equal by using the spacer, making it possible to securely load the solder balls on the electrode pads, one solder ball for each connection pad, and to reduce a probability that solder balls are not loaded or that a plurality of the solder balls are loaded onto a single connection pad.

Abstract: A method for manufacturing a printed wiring board, the method including forming a solder resist layer having a small-diameter aperture and a large-diameter aperture, each aperture exposing a respective joint pad. A metal ball having a first diameter is mounted in the small-diameter aperture by using a mask for small diameter metal balls, which includes a small-diameter aperture area that corresponds to the small-diameter aperture on the solder resist layer. A metal ball having a second diameter larger than the first diameter is mounted in the large-diameter aperture by using a mask for large diameter metal balls, which includes a large-diameter aperture area that corresponds to the large-diameter aperture on the solder resist layer.

Abstract: A method of manufacturing a printed wiring board includes preparing a wiring substrate having a conductive circuit, coating a solder-resist layer over the conductive circuit, leveling a surface of the solder-resist layer so as to obtain a maximum surface roughness in a predetermined range, removing the resin film from the surface of the solder-resist layer, and forming multiple openings in the surface of the solder-resist layer to expose multiple portions of the conductive circuit so as to form multiple conductive pads for mounting an electronic components.

Abstract: A solder ball loading method capable of securely loading solder balls on connection pads includes applying flux on each connection pad group of a printed wiring board flux is not applied to a contact portion between a spacer and the printed wiring board to keep the flux from attaching to the spacer. Because the flux is not attached to the spacer, when the mask is detached from the printed wiring board, the printed wiring board need not be inverted, and damage to the solder resist layer 70 is minimized. Further, the heights of the solder balls and the upper surface of the mask are made equal by using the spacer, making it possible to securely load the solder balls on the electrode pads, one solder ball for each connection pad, and to reduce a probability that solder balls are not loaded or that a plurality of the solder balls are loaded onto a single connection pad.

Abstract: A solder ball loading method capable of securely loading solder balls on connection pads includes applying flux on each connection pad group of a printed wiring board flux is not applied to a contact portion between a spacer and the printed wiring board to keep the flux from attaching to the spacer. Because the flux is not attached to the spacer, when the mask is detached from the printed wiring board, the printed wiring board need not be inverted, and damage to the solder resist layer 70 is minimized. Further, the heights of the solder balls and the upper surface of the mask are made equal by using the spacer, making it possible to securely load the solder balls on the electrode pads, one solder ball for each connection pad, and to reduce a probability that solder balls are not loaded or that a plurality of the solder balls are loaded onto a single connection pad.

Abstract: A solder ball loading method capable of securely loading solder balls on connection pads includes applying flux on each connection pad group of a printed wiring board flux is not applied to a contact portion between a spacer and the printed wiring board to keep the flux from attaching to the spacer. Because the flux is not attached to the spacer, when the mask is detached from the printed wiring board, the printed wiring board need not be inverted, and damage to the solder resist layer 70 is minimized. Further, the heights of the solder balls and the upper surface of the mask are made equal by using the spacer, making it possible to securely load the solder balls on the electrode pads, one solder ball for each connection pad, and to reduce a probability that solder balls are not loaded or that a plurality of the solder balls are loaded onto a single connection pad.

Abstract: A solder ball loading apparatus for loading solder balls onto pads of a printed wiring board includes a holding device for holding a printed wiring board having pads and holding a ball array mask having openings that correspond to the pads, one or more cylinder members is positioned over the holding device such that an opening portion of the cylinder member faces the holding device, the cylinder member gathering solder balls on the surface of the ball array mask under the cylinder member by suctioning air through the opening portion. A conveyor mechanism for moving the ball array mask and the printed wiring board relative to the cylinder member such that solder balls gathered under the opening portion of the cylinder member can be loaded onto the pads of the board through the openings of the mask held by the holding device.

Abstract: A method of manufacturing a printed wiring board with solder bumps includes forming a solder-resist layer having small and large apertures exposing a respective conductive pad of the printed wiring board, loading a solder ball in each of the small and large apertures using a mask with aperture areas corresponding to the apertures of the solder-resist layer, forming a first bump having a first height, from the solder ball in the small aperture, and a second bump having a second height, from the solder ball in the large aperture, the first height being greater than the second height, and pressing a top of the first bump such that the first height becomes substantially the same as the second height. A multilayer printed wiring board includes a solder-resist layer with apertures of differing sizes and solder bumps having substantially equal volumes but a difference in height no greater than 10 ?m.

Abstract: A solder ball loading apparatus for loading solder balls onto pads of a printed wiring board includes a holding device for holding a printed wiring board having pads and holding a ball array mask having of openings that correspond to pads of the printed wiring board, one or more cylinder members positioned over the holding device such that an opening portion of the cylinder member faces the holding device, the cylinder member gathering solder balls on the surface of the ball array mask under the cylinder member by suctioning air through the opening portion of the cylinder member, and a conveyor mechanism for moving the ball array mask and the printed wiring board relative to the cylinder member such that solder balls gathered under the opening portion of the cylinder member can be loaded onto the pads of the printed wiring board through the openings of the ball array mask held by the holding device.

Abstract: A method of manufacturing a printed wiring board with solder bumps includes forming a solder-resist layer having small and large apertures exposing a respective conductive pad of the printed wiring board, loading a solder ball in each of the small and large apertures using a mask with aperture areas corresponding to the apertures of the solder-resist layer, forming a first bump having a first height, from the solder ball in the small aperture, and a second bump having a second height, from the solder ball in the large aperture, the first height being greater than the second height, and pressing a top of the first bump such that the first height becomes substantially the same as the second height. A multilayer printed wiring board includes a solder-resist layer with apertures of differing sizes and solder bumps having substantially equal volumes but a difference in height no greater than 10 ?m.