Laminated body

The properties of metal and plastic have been combined in the form of a laminated tube, which consists of a polyethylene/ aluminium foil/polyethylene or similar laminated body fitted with a polyethylene nozzle and is less permeable than a conventional polyethylene tube with less tendency to draw air back. To date the main usage of laminated tubes has been for toothpastes, but wider pharmaceutical applications are now found. 

In this method, after alignment the green sheets are laminated layer by layer on a hot platen and pressure is applied. This is efficient since alignment and lamination are performed at the same time. However, as shown in Figure 7-11, the lowest green sheet is constantly heated, and it is pressed cumulatively many times. Therefore the lowest green sheet looses its flexibility so that the structure of the laminated body in the z axis becomes uneven making the method unsuitable for substrates with many layers. 

Figure 7-12 Conceptual diagram of delamination (a) with sufficient embodiment of the laminated body, and (b) with insufficient embodiment of the laminated body where each individual green sheet becomes separate and contracts.

Adherence between layers of green sheet in the laminated body is achieved with the following two methods. 

Internal interlayer delamination is where delamination occurs at the interface between the internal conductor and the ceramic, although the cracks do not reach to the outside of the substrate. The cause of the problem is an area of poor adherence between the green sheet and conductive paste in the laminated body. When there are many layers, or when the conductor on each layer is thick, there is a great difference in the thickness of the parts including the conductor and the parts with ceramic only, so that the laminated body is like a sandwich with a lot of filling (refer to Figure 7-17). Since this delamination occurs in order to release the stress within the laminated body, it takes a similar form to stepped interlayer delamination and circular delamination. 

Figure 7-18 The relationship between laminating density and the interlayer bonding strength of the laminated body.

Figure 7-22 shows a cross section of a laminated body after tensile stress is applied to the surface and vertical axis of the laminated body. A crack runs... 

Figure 7-21 The microstructure of a laminated body (a) the whole body, (b) the interlayer stmcture, and (c) the structure within a layer.

Figure 7-22 The cross sectional structure of a laminated body when tensile stress is applied.

Figure 8-13 The microstructure of the parts around copper vias when heat treated at various temperatures (a) laminated body (b) 600°C, (c) 850°C, and (d) 1,000°C.

In addition to this method, the following technique can be applied with separate processes using different heat treatments suited to each material (refer to Figure 8-21)[12], As shown in the figure, the laminated body is heat treated in the atmosphere at 600°C as the first step to burn off and completely eliminate the organic binder resin in the ceramic. At this time, the copper is transformed to copper oxide (CuO). Next, the substrate... 

Sandwiching the laminated body between material such as alumina that... 

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