Unitary vacuum tube incorporating high voltage isolation
A housing for microelectronic devices requiring an internal vacuum for operation, e.g., an image detector, is formed by tape casting and incorporates leads between interior and exterior of said housing where said leads are disposed on a facing surface of green tape layers. Adjacent green tape layers having corresponding apertures therein are stacked on a first closure member to form a resulting cavity and increased electrical isolation or channel sub-structures are achievable by forming adjacent layers with aperture dimension which vary non-monotonically. After assembly of the device within the cavity, a second closure member is sealed against an open face of the package in a vacuum environment to produce a vacuum sealed device.
1. The method of creating a unitary vacuum microelectronic imaging device comprising:
laminating a structure comprising first and second planar end plates and a plurality of insulating intermediate planar plates disposed therebetween, one of said end plates comprising a transparent wall with a photocathode on a surface,
forming a cavity in said laminated structure by positioning at least three of said intermediate plates against each other, each of said intermediate plates being selected as to have an aperture therein as to form a cavity in said laminated structure when said plates are positioned against each other, said at least three plates having apertures that vary non-monotonically when positioned in series with one another,
positioning and bonding said transparent end plate onto an intermediate plate by flowing an indium seal between said end plate and said intermediate plate with said photocathode surface on said end plate facing said cavity,
positioning and bonding a microelectronic device at the other said end plate opposite to said end plate with a transparent wall, and
creating a vacuum pocket within said cavity, said indium seal being pressed into said bonding relationship sealing said vacuum device while the assembly of said device is maintained in an ultra high vacuum environment.
2. The method of creating a unitary vacuum microelectronic imaging device in accordance with claim 1 in which the surface of said intermediate plate is first metallized with a titanium-tungsten and nickel gold deposition prior to flowing said indium seal between said end plate and said intermediate plate.
3. A method in accordance with claim 1 in which said transparent end plate is urged against said indium seal with a pressure in the range of between 1000 to 8000 psi.
4. A method in accordance with claim 1 in which a seal is obtained by pressing said transparent end plate against said indium seal while said device is maintained in a vacuum chamber.
5. A method in accordance with claim 4 in which said vacuum chamber is maintained under ultra high vacuum conditions.
6. A method in accordance with claim 4 in which said vacuum chamber is maintained at a vacuum of about 10 −10 Torr.