Method of making a multi-layer interconnect

#The field of the invention is multi-layer substrates/interconnects.

#An integrated circuit (IC) package is a housing which environmentally protects the IC, facilitates testing of the IC, and facilitates the use of the IC in high-yield assembly processes. Such a package functions to protect an IC from mechanical and environmental stresses and electrostatic discharge. It also functions to provide a mechanical interface for testing, burn-in, and interconnection to a higher level of packaging such as a circuit card.

#In many IC packages a substrate acts as an interconnecting layer between the terminals or pads on the IC, and the connectors or leads of the package. The substrate is typically mechanically and electrically coupled to both the IC and the package leads. The substrate may be made from a ceramic or organic material, may be rigid or flexible, and may comprise a single layer or multiple layers laminated together.

#FIG. 1 is a perspective view of a portion of a multi-celled assembly embodying the invention.

#FIG. 2 is a perspective view of a portion of a multi-celled assembly embodying the invention.

#FIG. 3 is a perspective view of a layer-pair according to the disclosed invention.

#Referring to FIG. 1, an assembly 1 of HDI cells 5 can be seen to be a multi-celled assembly comprising a plurality of cells 5 wherein each cell 5 is bound to adjacent cells 5 and adhesive material 22. Cells 5 are preferably laid out horizontally to form a rectangular panel or a linear strip of interconnected cells, but may have other forms as well. If formed into a rectangular panel, cells 5 are preferably laid out in rows and columns with the number of cells in each row preferred to be but not necessarily equal to the number in the other rows and the number of cells in each column preferred to be but not necessarily equal to the number in the other columns. Although not limited in number or particular layout, it is contemplated that panels having a total of T cells arranged in rows containing X cells and columns containing Y cells where (T, X, Y) are (4, 2, 2), (4, 1, 4), (7, 1, 7), (8, 2, 4), (9, 3, 3), (9, 1, 9), (12, 3, 4), (16, 4, 4), (16, 16), (25, 5, 5), (36, 6, 6) may be particularly desirable. If formed into linear strips it is contemplated that 1 or more parallel rows having a large number of columns may be rolled for ease in later transportation, handling and processing.

#Cells 5 may each have unique shapes, or, as shown in FIG. 1, to comprise a uniform interlocking shape. However, it is currently preferred that cells 5 comprise uniform rectangular shapes. It is contemplated that uniformity between cells is advantageous when forming new multi-celled units from the good cells. It is also contemplated that making the shapes interlocking helps to prevent untimely separation of the cells. However, with an appropriate choice of adhesive material 22 non-interlocking rectangular shapes are sufficient, and alternative shapes such as ovals may be chosen.

#Referring to FIG. 2, cells 5 can be seen to comprise layer-pairs 10 and bond-ply layers 20. Although cells comprising a single layer-pair 10 are contemplated, the assembly and methods disclosed herein are thought to be particularly advantageous when the cells 5 are stacks of alternating layer-pairs 10 and bond-ply layers 20 and the cells/stacks 5 have layer-pairs 10 on both ends of the stack.