Abstract: Thermoelectric devices having enhanced thermal characteristics are fabricated using multilayer ceramic (MLC) technology methods. Aluminum nitride faceplates with embedded electrical connections provide the electrical series configuration for alternating dissimilar semiconducting materials. Embedded electrical connections are formed by vias and lines in the faceplate. Methods for forming tunnels through lamination and etching are employed. A portion of the dissimilar materials are then melted within the tunnels to form a bond. Thermal conductivity of the faceplate is enhanced by adding electrically isolated vias to one surface, filled with high thermal conductivity metal paste. A low thermal conductivity material is also introduced between the two high thermal conductivity material faceplates. Alternating semiconducting materials are introduced within the varying thermal conductivity layers by punching vias within greensheets of predetermined thermal conductivity and filling with n-type and p-type paste.

Abstract: An interface layer for separating first and second microelectronic ceramic substrates during firing includes a thermally degradable binder, preferably a polymer, that degrades at temperatures above room temperature and below a firing temperature for the microelectronic ceramic substrates, and a separating material, such as boron nitride or graphite. The method of making the interface layer includes mixing the binder, one or more solvents for the binder, a plasticizer and the separating material for a sufficient period of time to form a homogeneous mass, then casting the material in a thin sheet to form the interface layer.

Abstract: A ceramic contact sheet and setter tile with controlled porosity is introduced, along with the method for making the same. The amount of porosity is controlled by the volume percentage, particle size, and particle shape of a fugitive phase which can be added to the original refractory material slurry used to fabricate setter tiles and contact sheets. The fugitive phase can be used independently to introduce porosity in setter tiles and contact sheets or in conjunction with partial densification. Since porosity is not solely dependent upon partial sintering, higher porosity levels can be achieved with less impact on subsequent mechanical properties of the resultant refractory material.

Abstract: Thermoelectric devices having enhanced thermal characteristics are fabricated using multilayer ceramic (MLC) technology methods. Aluminum nitride faceplates with embedded electrical connections provide the electrical series configuration for alternating dissimilar semiconducting materials. Embedded electrical connections are formed by vias and lines in the faceplate. Methods are employed for forming tunnels through lamination and etching. A portion of the dissimilar materials are then melted within the tunnels to form a bond. Thermal conductivity of the faceplate is enhanced by adding electrically isolated vias to one surface, filled with high thermal conductivity metal paste. A low thermal conductivity material is also introduced between the two high thermal conductivity material faceplates. Alternating semiconducting materials are introduced within the varying thermal conductivity layers by punching vias within greensheets of predetermined thermal conductivity and filling with n-type and p-type paste.

Abstract: A cleaning method and related apparatus for cleaning semiconductor screening masks using an aqueous alkali detergent solution applied under high pressure simultaneously from both sides of the mask, followed by a drying step that uses air knives to blow off the mask surface any residual cleaner solution.

Abstract: A ceramic contact sheet and setter tile with controlled porosity is introduced, along with the method for making the same. The amount of porosity is controlled by the volume percentage, particle size, and particle shape of a fugitive phase which can be added to the original refractory material slurry used to fabricate setter tiles and contact sheets. The fugitive phase can be used independently to introduce porosity in setter tiles and contact sheets or in conjunction with partial densification. Since porosity is not solely dependent upon partial sintering, higher porosity levels can be achieved with less impact on subsequent mechanical properties of the resultant refractory material.

Abstract: Greensheets having enhanced flexibility and strength are prepared from a greensheet casting composition comprising alumina or other ceramic having a mean particle size of less than about 1 micron and being substantially unimodal, a binder resin, a solvent system and a plasticizer. The greensheets may be formed having a thickness of about 50 microns using conventional greensheet fabricating devices. The greensheets are particularly suitable as dielectric layers for internal layer capacitors in a multilayer ceramic substrate. A preferred co-sintering heating profile to avoid blistering of the MLC package is also provided to form the capacitor containing MLC.

Abstract: An apparatus and method is provided for vacuum screen printing a greensheet having vias and both vias and open areas whereby vacuum leakage in the apparatus is minimized and avoids bowing of the screen over the open area of the greensheet. An interposer apparatus is provided comprising at least two layers having vertical through openings in registration with the via openings of the greensheet and screen. The interposer also comprises vertical through openings communicating with the open area of the greensheet and with vent channels of the interposer. A porous membrane is also used either alone or in conjunction with the interposer to provide enhanced screening results.

Abstract: A cleaning method and related apparatus for cleaning semiconductor screening masks using an aqueous alkali detergent solution applied under high pressure simultaneously from both sides of the mask, followed by a drying step that uses air knives to blow off the mask surface any residual cleaner solution.

Abstract: Disclosed is a method of forming an aluminum nitride article. The method includes the steps of adding platinum to a composition including a binder, aluminum nitride particles and a sintering aid; forming the composition into an article; placing the article in a substantially non-carbonaceous container; and sintering the article in a reducing atmosphere to cause removal of the binder and densification of the aluminum nitride article, wherein the platinum catalyzes the removal of the binder.

Abstract: Disclosed is an electronic packaging substrate which includes a sintered ceramic body having at least one internal layer of wiring and at least one cooling channel internal to and integral with the sintered ceramic body for cooling a heat-generating electronic device placed on the sintered body. Also disclosed is a method of making the electronic packaging substrate.

Abstract: A process for making multiple microelectronic ceramic substrates uses an interface layer between stacked layers of green sheets that are laminated with the interface layer, then fired to produce the ceramic substrates. The interface layer acts to protect the substrates, and to hold them together before firing, then thermally degrades at a desired point in the firing cycle to separate the individual substrates. The invention also includes the ceramic substrates produced by the method.

Abstract: An interface layer for separating first and second microelectronic ceramic substrates during firing includes a thermally degradable binder, preferably a polymer, that degrades at temperatures above room temperature and below a firing temperature for the microelectronic ceramic substrates, and a separating material, such as boron nitride or graphite. The method of making the interface layer includes mixing the binder, one or more solvents for the binder, a plasticizer and the separating material for a sufficient period of time to form a homogeneous mass, then casting the material in a thin sheet to form the interface layer.

Abstract: The present invention relates generally to a new apparatus and method for screening using electrostatic adhesion. More particularly, the invention encompasses an apparatus that uses an electrostatic charge during the screening process for a semiconductor substrate. Basically, a backing layer is adhered to a green ceramic sheet using an electrostatic charge, while the green ceramic sheet is processed.

Abstract: Method for producing ceramic laminates from a plurality of greensheet layers which include one or more thin greensheet layers, e.g. having a thickness less than about 3 mils, with interposed patterned circuit layers and conductive vias, while avoiding the loss of strength and the distortion encountered when paste compositions are pre-applied to such thin greensheet layers. The invention avoids the aforementioned problems by the use of a plurality of greensheet layers including thicker, paste-resistant greensheet layers having a thickness greater than the thin greensheet layer, e.g., between 5 and 10 mils, each pair of the thicker greensheet layers confining therebetween an unscreened thin greensheet layer, one of the thicker greensheet layers also being screened with the circuit pattern layer normally applied to the interposed thin greensheet layer. Thereafter the superposed layers are laminated and sintered to form the composite.

Abstract: Disclosed is an aluminum nitride body having graded metallurgy and a method for making such a body. The aluminum nitride body has at least one via and includes a first layer in direct contact with the aluminum nitride body and a second layer in direct contact with, and that completely encapsulates, the first layer. The first layer includes 30 to 60 volume percent aluminum nitride and 40 to 70 volume percent tungsten and/or molybdenum while the second layer includes 90 to 100 volume percent of tungsten and/or molybdenum and 0 to 10 volume percent of aluminum nitride.

Abstract: Disclosed is an aluminum nitride body having graded metallurgy and a method for making such a body. The aluminum nitride body has at least one via and includes a first layer in direct contact with the aluminum nitride body and a second layer in direct contact with, and that completely encapsulates, the first layer. The first layer includes 30 to 60 volume percent aluminum nitride and 40 to 70 volume percent tungsten and/or molybdenum while the second layer includes 90 to 100 volume percent of tungsten and/or molybdenum and 0 to 10 volume percent of aluminum nitride.

Abstract: A large ceramic substrate article for electronic applications including at least one layer of sintered ceramic material, the layer including a plurality of greensheet segments of ceramic material joined edge to edge. Also disclosed is a method of fabricating a large ceramic greensheet article as well as a large ceramic substrate article.

Abstract: Process for producing circuitized greensheets including multi-layer ceramic sub-laminates and composites comprising thin ceramic greensheets carrying and thin, fine line patterned conductive metal layers. The invention comprises releasably-supporting the thin greensheets on a temporary carrier support having an ablatable release layer, preferably over a patterned conductive layer, and filling the vias with conductive metal paste, whereby the thin greensheets are supported against warpage and distortion. The supported greensheets are formed as single layers, pairs and stacks thereof, as desired, and thereafter separated from the temporary support for use.

Abstract: A novel metal filled via composition for use with ceramics. The via composition can be formulated to have a volume shrinkage approximating that of the ceramic material, and thus overcomes the problem of volume shrinkage mismatch between the via (particularly copper filled via) and ceramic upon sintering. The novel via composition exhibits enhanced adhesion to the ceramic. A sintering process by which shrinkage of the novel via composition is controlled and adhesion is improved is also disclosed.