Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Patent
1997-07-16
2000-01-04
Jones, Deborah
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
174262, 427 97, 428901, B32B 300
Patent
active
060107693
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a multilayer wiring board (MLB) and a method for manufacturing the same, and more particularly to a multilayer wiring board in which via hole is not for connection between conductor wiring layers and a method for manufacturing the same. The present invention also relates to prefabricated materials for a multilayer wiring board, and the invention relates more particularly to a prefabricated material for a multilayer wiring board performing a via connection between conductive wiring layers by means of conductive pillars.
In addition, the invention relates to an electronic element, and more particularly to an electronic element provided with connecting portions suitable for high-density mounting to an external circuit.
Furthermore, the invention relates to an electronic element package having at least an electronic element mounted on a wiring board, and for example, relates to such an electronic element package having a highly integrated electronic element mounted on a wiring board such as a chip-sized package (CSP) of a semiconductor device.
Still further, the invention relates to a method for forming a conductive pillar used in a via connection in a multilayer wiring board or a connecting portion between an electronic element and an external circuit, as described above.
BACKGROUND ART
As various electronic equipment becomes smaller in size and higher in function, the demand for higher mounting density of electronic elements has been increased. To meet this demand, a multilayer wiring board in which an insulating layer and a wiring layer are stacked alternately has been widely used. To meet the demands for high mounting density and high performance, the wiring board having multiple wiring layers and each wiring layer is connected by via connection such as a via hole to the other wiring layer.
FIG. 24 is a sectional view showing one example of a construction of conventional multilayer wiring board. This multilayer wiring board 901 is constructed by via connecting wiring circuits formed in five layers. A first wiring layer 901, a second wiring layer 902, a third wiring layer 903, a fourth wiring layer 904, and a fifth wiring layer 905 are each formed by patterning a conductor layer. These wiring circuits are isolated by an insulating layer 906.
A general method for manufacturing a multilayer wiring board having a typical structure as shown in FIG. 24 will be described below.
First, in order to connect the layers of a double faced laminate, in which a conductor layer such as copper foil is bonded to both faces of insulating layer, through holes 907 are formed at portions to be electrically connected of the double faced laminate. Chemical plating is applied to the inside wall surface of the through hole 907, and further electroplating is applied to increase the thickness of a conductor layer 907b on the inside wall surface of the through hole 907, thereby enhancing the reliability of connection between layers.
Then, the conductor layers on both faces are patterned into a predetermined circuit by, for example, the photo-etching process.
Next, an insulating layer such as a prepreg layer is laminated on the patterned conductor layer and further a conductor layer such as copper foil is laminated to achieve integration by heating and pressurization. By repeating the process from the formation of through holes to the patterning of circuit, a multilayer wiring board is formed.
Such a multilayer wiring board, in which via hole is used for connection between wiring layers, has a problem in that it is difficult to respond to high-density mounting of a electronic element.
For example, generally speaking, neither wiring is formed nor electronic elements are mounted in the region where a through hole is provided, so that the increase in wiring density and mounting density is restricted. Also, in recent years, along with high-density mounting of electronic elements, the wiring of wiring board has become dense. If attempts are made to decrease the diameter of through hole in
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Fujiwara Madoka
Ikegaya Fumitoshi
Mori Takahiro
Odaira Hiroshi
Sasaoka Kenji
Jones Deborah
Kabushiki Kaisha Toshiba
Lam Cathy F.
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