Patent ID: 8257529

Claim:
A method for producing a multilayer ceramic substrate, comprising the steps of: preparing a glass-ceramic paste including glass and a ceramic powder; preparing a plurality of inner ceramic green sheets for forming inner layers; forming a conductive pattern on at least one sheet of the plurality of inner ceramic green sheets, the conductive pattern being made of an Ag-based material; forming a laminate including an inner layer portion and surface portions, the inner layer portion being formed by stacking the plurality of inner ceramic green sheets, and the surface portions being formed by applying the glass-ceramic paste to outward facing surfaces of the outermost sheets of the inner ceramic green sheets defining the inner layer portion; and firing the laminate; wherein the conductive pattern includes main-surface conductive films formed on at least one of the outward facing surfaces of the outermost sheets of the inner ceramic green sheets defining the inner layer portion; and at least one of the surface portions of the laminate are formed so as to cover peripheries of the main-surface conductive films and leave central portions of the main-surface conductive films exposed; the surface portions of the laminate have a thermal expansion coefficient less than a thermal expansion coefficient of the inner layer portion; and a difference between the thermal expansion coefficient of the inner layer portion and the thermal expansion coefficient of the surface portions of the laminate is at least about 1.0 ppmK −1 ; and between the step of forming the laminate and the step of firing the laminate, the method further comprises a step of pressing the laminate such that the exposed central portion of at least one of the main-surface conductive films and an outward facing surface of the at least one of the surface portions of the laminate are planarized.