Abstract: A tool for segmenting a stack of bonded IC chips into short stacks includes a heat conducting base having at least one cavity in its upper face for receiving a portion of an IC chip stack. The length and width dimensions of the cavity are essentially the same as the corresponding dimensions of the stack. The depth of the cavity is selected to correspond to the desired thickness of the short stack to be formed from the stack. The base is heated to raise the temperature of the cavity walls to heat the stack above the softening point of the bonding material. A driver is movably mounted on the base for contact with a portion of a face of the stack extending above the opening of the cavity, and a threaded rod supported on the base urges the driver against the stack to effect separation of the extending portion of the stack from the segment portion which remains in the cavity. A track in the upper surface of the base is provided for travel of the driver.

Abstract: A method and product are disclosed in which multiple solder bumps on a first planar surface are guided into engagement with terminals on a second planar surface by means of holes formed (by a photolithographic process) in a dielectric layer, which has been added to the second surface to provide the holes (or sockets) through which the solder bumps (or plugs) extend. The perforated (hole-providing) layer may be formed of one of several materials. The preferred perforated layer material is a photo-definable polyimide, which is hardened by heating after the holes have been formed. Small solder bumps may be formed inside the holes on the second surface, in order to facilitate bonding between the solder bumps on the first surface and the terminals on the second surface.

Abstract: A method for fabricating stacks of IC chips into modules providing high density electronics. A relatively large number of layers are stacked, and then integrated by curing adhesive applied between adjacent layers. A large stack is formed, various processing steps are performed on the access plane face of the large stack, and then the large stack is segmented to form a plurality of smaller, or short, stacks. Means are provided for causing separation of the larger stack into smaller stacks, without disturbing the adhesive which binds the layers within each small stack.

Abstract: A process is disclosed which applies advanced concepts of Z-technology to the field of dense electronic packages. Starting with standard chip-containing silicon wafers, modification procedures are followed which create IC chips having second level metal conductors on top of passivation (which covers the original silicon and its aluminum or other metallization). The metal of the second level conductors is different from, and functions better for electrical conduction, than the metallization included in the IC circuitry. The modified chips are cut from the wafers, and then stacked to form multi-layer IC devices. A stack has one or more access planes. After stacking, and before applying metallization on the access plane, a selective etching step removes any aluminum (or other material) which might interfere with the metallization formed on the access plane. Metal terminal pads are formed in contact with the terminals of the second level conductors on the stacked chips.

Abstract: A system for protecting a radiation-responsive device, such as an infrared sensor in an imaging system includes a plasma switch operative in response to amplitude of incident radiation. The protection system is suitable for protecting the infrared sensor from a high-intensity laser beam which might impinge upon receiving optics of the imaging system. The plasma switching responds differently to different portions of the electromagnetic spectrum, a lower frequency portion being either transparent or reflective of the infrared radiation, while an upper frequency portion absorbs radiation to initiate a high or low density of free-charge carriers in the plasma dependent on the intensity of photons injected into the plasma in the higher frequency band.

Abstract: Apparatus is disclosed for protecting delicate sensor optics from the damaging effects of unwanted powerful laser radiation. A thin-film reflective pellicle 14 is placed in the light path of a sensor telescope. Incident light 10 is focused by some combination of optical elements 12 onto the reflective surface 28 of the laser hazard protector 14. The reflected light 10 is then imaged by further optics 16 onto a detector array 18. Should a signal too strong for the detector enter the sensor aperture with the incident light 10, the focused power at the surface of the pellicle 28 will ablate the carbon and metallic film, burning a hole in the pellicle, and the high-power light 11 will be deflected from the detector array and be absorbed instead by the beam dump 20. A power meter within the beam dump determines when the laser threat has stopped and signals the turning mechanisms 15a and 15b to turn the pellicle reflector to a fresh position at which point normal sensor operations may resume.

Abstract: We disclose and claim a process for fabricating wraparound solar cells wherein vertical slots are scribed in a semiconductor wafer to initially define the lateral dimensions of the cell. Thereafter, photolithographic masking, etching and diffusion steps are used to define the geometry of a p-n junction of the cell. Then, using lift-off photolithography and a multiple-element metal deposition process, the solar cell grid lines are formed on one surface of the cell and p- and n-type metal contacts are extended around to the opposite surface of the cell. In this manner, the dimensions of the cell can be made less than the diameter of the semiconductor wafer from which it is made.