Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2001-04-27
2003-09-30
Talbott, David L (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C029S852000
Reexamination Certificate
active
06627823
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the development and production of an equipment based on microelectronics components and semiconductor devices, and may be widely used in the production of multilayered connection plates. The invention is directed on reducing the labor input and cost of producing the multilayered plates while increasing the conductor spreading density and reducing the number of connection layers. An application of the present invention in producing the connection printed circuit cards for mass electronic equipment with high specific characteristics in the form of multichip modules (MCM) is particularly promising.
BACKGROUND OF THE INVENTION
A multilayered plate based on alumina ceramics is known, the plate comprising alternating ceramic layers on which surfaces are formed conductors by applying and burning the conductive paste. The conductors of adjacent layers are coupled each other by means of holes in ceramic layers filled with a conductive paste which forms, after heat treating, contact nodes for connecting the conductors placed on the surfaces of adjacent layers according to a specific connection scheme (SU 1443781 A, Int. Cl. H 05 K 3/46, 1987).
Advantages of the ceramic multilayered plates are the group character and producing adaptability of processes for forming the contact nodes and assembling the layers into a single multilayered plate.
Nevertheless, the multilayered ceramic plates have great weight and substantial thickness with the contact spreading density and the number of connection layers which do not meet the requirements placed to the modern electronic equipment based on components with great number of leads spaced with a fine pitch. Moreover, due to substantial technological differences in linear sizes of mounting elements on the plate surface, in a high-temperature treating of ceramics (ceramics caking conditions are hardly controllable) great problems occur with aligning contact pads on the plate and precision leads of housing components, which impedes an automation of component mounting on the plate surface, and finally, leads to rising a cost of the equipment based on ceramic plates. Even greater difficulties occur while performing the mounting of housing-less IC chips with great number of leading contacts. Thus, the ceramic multilayered plates are generally used in a special equipment with high requirements on a resistance to environment factors.
A multilayered connection plate on polyimide base comprising layers of polymide film having conductive paths placed on both surfaces of every layer is also known. In order to couple conductors, a metallized through holes 0.1 mm in diameter are formed with every layer. For connecting the layers electrically and mechanically into a multilayered printed circuit plate with the single conductor spreading topology are used specifically formed metallized through holes about 1.5 mm in diameter arranged in the form of matrix with a regular pitch common for all layers which form, after aligning, the matrix of channels piercing the multilayered plate throughout. The conductors and metallized holes are formed by methods of lithography and spraying the metallization with a subsequent galvanic build-up to a required thickness and tinning those places in which should be soldered joints. Assembling the layers into a multilayered structure is performed by soldering the joints between the metallized through holes with the methods of vacuum soldering (Panov E. N. The peculiarities of assembling the specialized LSIC on basic matrix chips. Moscow: “Vysshaya Shkola”, 1990. Pp. 31-34).
Soldered joints between the through holes are contact nodes serving for electrical interfacing the conductive structures of all layers into a single connection scheme of the multilayered connection plate.
A utilization of the polyimide as an insulating material having unique electrophysical parameters provides high technological and operating features to polyimide multilayered connection plates.
However, the presence of the matrix of metallized through channels piercing the multilayered plate throughout presents difficulties in spreading the connections, which leads to an increase of the number of layers, to a degradation of the plate testability and reducing of plate reliability, as well as to an increase of the polyimide expenditure and complication of the plate producing technology. As a whole, all of this increases the cost and makes impossible to utilize such plates in mass production manufacturing.
A multilayered printed circuit plate with a high density connection is known, comprising pairs of connection layers produced by means of technological substrate and separated with electrical insulating adhesion gaskets to stick the connection layers together. The conductors of adjacent connection layers are interconnected electrically by contact nodes made in the form of metallized through hole (SU 970737 A, Int. Cl. H 05 K 3/46, 1981).
The multilayered plates made according to that invention, while solving the problem of increasing the contact spreading density at the cost of excluding through channels piercing the whole multilayered plate throughout, could not, however, comprise more than 4 metallized connection layers, which is a significant limitation for their usage in the modern equipment (in comparison, the multilayered polyimide plate could comprise up to 30 metallization layers).
The closest technical solution to the present invention by the technical essence and achieved result is a multilayered connection plate based on polyimide, comprising dielectric layers having conductive paths formed on their surfaces, and forming connection layers of the multilayered plate, and also contact nodes made in the form of soldered joints of aligned metallized holes in the connection layers, the nodes performing an inter-layer connection of conductive paths placed both on adjacent and remote connection layers (Panov E. N. The peculiarities of assembling the specialized LSIC on basic matrix chips. Moscow: “Vysshaya Shkola”, 1990. Pp. 16-34).
The main disadvantages of this technical solution are:
a great expenditure of useful connection space due to the matrix of metallized through channels in the multilayered plate, the channels being formed by soldered metallized holes of the connection layers, which decreases substantially the specific of the interconnection spreading density and leads to an increase of the number of connection layers, and hence, to an increase in the labor input and cost, as well as to a decrease of the reliability of the whole plate due to an increase of the number of soldered joints;
a presence of the insulating gaskets between the connection layers with two-side metallization, comprising the metallized holes in the places where the through channels pierce the multilayered plate, which leads to a factual doubling of the number of layers in the plate and doubling of the number of soldered joints, i.e., to a significant complication of the plate, and hence, to a rise of its cost and decrease of its reliability.
SUMMARY OF THE INVENTION
The problem to be solved by the present invention consists in creating a multilayered connection structure comprising contact nodes of an original design, which usage allows to significantly increase the specific contact spreading density while decreasing substantially a design complexity, labor input and cost of production of the connection layers and multilayered connection structure as a whole.
Moreover, a utilization of the proposed contact node allows to enhance the controllability, reproducibility and reliability of connections in the multilayered connection plate.
The indicated technical result is achieved at the cost of utilizing the original contact nodes in the design of the proposed multilayered connection structure, providing the electrical and mechanical connection between layers.
The set problem is solved with achieving the mentioned result by that in the multilayered connection plate comprising layers of a dielectric material having conductive paths on their sur
Ljubimov Viktor Konstantinovich
Taran Alexander Ivanovich
Knobbe Martens Olson & Bear LLP
Norris Jeremy
Talbott David L
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