Inspection of unsintered single layer or multilayer ceramics using a

Abstract

Apparatus and methods are disclosed for inspecting unsintered single or multiple layer ceramic specimens containing or carrying metal paste patterns of the type commonly used to ultimately form laminated multilayer ceramic (MLC) carriers for large scale integrated (LSI) chips. A relatively large surface area of an unsintered ceramic specimen (large in comparison with the minimum feature size of the paste patterns) is temporarily electrically contacted with a conforming electrode. The conforming electrode makes non-damaging electrical contact to any metallic paste exposed at the contacted area. Electric charge is either collected or delivered by this electrode, depending upon the mode of operation. The electrical continuity of metallic paste paths which contact the electrode and extend through the unfired ceramic specimen to surface positions not contacted by the electrode are tested either by delivering electric charge to the other surface locations and correlating therewith the collection of charge by the electrode, or by delivering charge by the electrode to all paste paths in contact therewith and detecting the presence of charge at the other surface locations. A preferred method either for delivering charge to such other surface locations or for detecting charge at such other surface locations is by using an electron probe beam. Various embodiments for the conforming electrode are described.