Patent ID: 7951446

Claim:
A hard-to-sinter constraining green sheet disposed at least one of top and bottom surfaces of a non-sintered multi-layer ceramic substrate, the hard-to-sinter constraining green sheet comprising: a first constraining layer having a surface to be positioned on the multi-layer ceramic substrate, the first constraining layer including a first organic binder and a first inorganic powder having a spherical shape or a quasi-spherical shape; and a second constraining layer bonded to a top surface of the first constraining layer and including a second organic binder and a second inorganic powder having a flake shape, the second constraining layer having a powder packing density lower than that of the first constraining layer, so that the first constraining layer with a higher powder packing density can increase a capillary force enabling movement of a binder in the ceramic substrate, and the second constraining layer with a lower powder packing density can ensure a passage for de-binding, wherein a content ratio of the second organic binder with respect to a total weight of the second constraining layer is lower than a content ratio of the first organic binder with respect to a total weight of the first constraining layer, the second inorganic powder has an average diameter (d) and an average thickness (h) in a predetermined range and satisfying h/d≦0.5, and the average diameter (d) of the second inorganic powder is greater than an average particle size of the first inorganic powder.