Abstract: A single layer copper foil tape is provided having a center core and connected lead beams. Etched apertures are formed to separate adjacent lead beams and to form relatively high strength foil straps connecting edge portions of the foil tape and the center core. Score lines may be etched at the ends of each of the lead beams to form breakaway links at such ends. The inner ends of the lead beams are then bonded to a semiconductor die at its contact pad or bumps and the resultant subassembly aligned with inner ends of the fingers of a metal lead frame array or other set of external leads such as a pin grid array and the outer ends of the lead beams bonded to such fingers. At this point, all of the remaining portions of the foil tape are peeled or pulled off the assembly, the lead beams being separated at their breakaway links, leaving only the lead beams connecting the die and set of external leads intact.

Abstract: Extremely cold gaseous nitrogen is used as a cooling medium in the highly exothermic reaction between a chemical etch solution and silicon. This greatly increases the throughput of silicon material through the etchant over prior art techniques, particularly where it is desired to maintain the temperature of the etchant solution below 25.degree. C.

Abstract: A laser assembly that includes a novel glass laser disc having an annular alkali lead borate glass coating for use in the assembly is disclosed. The annular coating has an index of refraction that is about 3 to 12% greater than the index of refraction of the laser disc, the thermal properties also being sufficiently matched with the glass laser disc so as to prevent the development of undesirable strains therein, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K.sub.2 O that is present is limited to an amount of not substantially more than about 1% by weight and an effective energy absorbing amount of heavy metal oxide that absorbs energy at a wavelength of about 1.06 microns to prevent parasitic oscillations. The heavy metal oxides include oxides of transition metals of the 3d, 4d, 4f, 5d and 5f orbital series.