摘要:
Reaction-brazing of tungsten or molybdenum metal bodies to carbonaceous supports enables an x-ray generating anode to be joined to a preferred lightweight substrate. Complementary surfaces are provided on a dense refractory metal body and a graphite or a carbon-carbon composite support. A particulate braze mixture comprising Hf or Zr carbide, Mo or W boride, Hf or Zr powder and Mo or W powder is coated onto the support surface, and hafnium or zirconium foil may be introduced between the braze mixture and the refractory metal body complementary surface. Reaction-brazing is carried out at or near the eutectic point of the components, which may be influenced to some extent by the presence of carbon and boride. Heating to about 1865° C. for a Mo/Hf combination creates a thin, dense, strong braze that securely joins the two bodies and creates a thin barrier of carbide and boride microphases near and along the interface with the carbon support that diminishes carbon diffusion into the metal body during extended exposures at elevated temperatures (above those presently used in x-ray tubes), even well above the eutectoid temperature.
摘要:
A method and system for instantaneous heat-sink soldering comprising a gripper device, an intense heat source, and an air-jet cooling system is provided for soldering terminals to structures of dissimilar material composition. The gripper device is adapted to secure the terminal between a pair of jaws and selectively position the terminal closely adjacent the structure. The jaws further serve as heat sinks to continually remove residual heat from the terminal, both during and after the application of heat to the terminal. Upon termination of the heat application, air-jet cooling is provided to the terminal to quickly cool the terminal and the molten layer of solder. The method of rapidly heating and cooling the terminal and layer of solder prevents the annealing of certain silica substrates and provides better solder connections.
摘要:
Methods of forming arrays of electrical interconnects between substrates are provided. These methods allow the use of large interconnect bump arrays to physically and electrically connect substrates without the need to use excess pressure on the substrates to form the interconnects, thus reducing damage to the substrates. To form the interconnects, an array of bumps is formed on a first substrate from a material that forms a eutectic composition with a second material. An array of bumps composed of the second material is formed on the second substrate. The arrays are aligned and the bumps contacted at a temperature above the eutectic temperature of the eutectic composition. Each of the bumps on the first substrate melts and diffuises into the corresponding bumps on the second substrate to form the interconnects.
摘要:
Lands formed on a flexible printed circuit board are electrically connected with lands formed on a rigid printed circuit board through solder. At this point, solder resist is formed between neighboring two lands on the rigid printed circuit board, and is terminated with an end portion that is interposed between the rigid printed circuit board and the flexible printed circuit board. Accordingly, even when surplus solder is extruded onto the rigid printed circuit board, the solder resist can prevent solder bridges from being formed between the lands.
摘要:
An automatic wave soldering apparatus includes a solder reservoir for holding a supply of molten solder and a solder nozzle vertically disposed in the solder reservoir to establish a solder wave through which a printed circuit board is moved. A pair of trapezoidal elements are secured within the nozzle. A Y-shaped baffle is disposed between the trapezoidal elements to form upwardly inclined narrowed upstream and downstream outlets. The upstream and downstream outlets are inclined at an acute angle against and in the direction of movement of the printed circuit board, respectively. A pair of valves are disposed at opposite sides of the baffle to selectively open and close the outlets. The bottom side of each of the trapezoidal elements forms a step to promote turbulence in the solder wave. The trapezoidal elements and the baffle collectively serve to increase the flow velocity of the molten solder through the outlets.
摘要:
An apparatus and method of forming improved wire bonds between the contact pads on semiconductor devices and individual lead frame fingers of a lead frame. The apparatus and method include the use of a penetrating individual independent lead finger clamp during the wire bonding process to provide increased stability of the individual lead finger for improved bonding by the clamp penetrating a portion of the lead finger being bonded. If desired, the apparatus and method also provide for the use of either a penetrating or nonpenetrating fixed clamp for the lead fingers during the wire bonding process in addition to the penetrating individual independent lead finger clamp during the wire bonding process to provide increased stability of the individual lead finger for improved bonding. The apparatus and method contemplate the replacement of the penetrating fixed clamp with another, or second, penetrating independent clamp in addition to the first individual independent lead finger clamp during the wire bonding process.
摘要:
A method for increasing the manufacturing certainty of soldered connections between a ceramic carrier and a printed-circuit board. It includes the method step of applying a first decomposition-resistant metallization layer on a ceramic carrier and the subsequent imprinting onto the first metallizing layer of a second metallizing layer, improving the wetting performance. In this manner, it is possible to achieve an increase in the overall metallizing layer thickness in the edge area of a soldered connection, whose solder rise in turn makes possible an optical, fully-automatic monitoring of the soldered connection.
摘要:
A wire bonding apparatus equipped with a chip heating assembly which is installed above a heater block that contains heaters so as to heat the chip portion of a device such as a semiconductor device, and a cooling pipe which is installed in the heater block so as to cool the heater block. The temperature of the bonding surface of the device is maintained by the chip heating assembly at a temperature that allows bonding to be executed while the heater block is cooled by cooling water or a cooling air draft that flows through the cooling pipe so that the temperature of the heater block is maintained at a low temperature that cause no softening of the resin substrate of the device.
摘要:
A wire-bonding machine includes a heat block for supporting a lead frame during wire-bonding. A clamp mechanism in the machine clamps leads of the lead frame during wire-bonding by fixedly holding sets of the leads against the heat block one set at a time. A wire-bonding tool wire-bonds leads clamped by the clamp mechanism to bond pads on an integrated circuit die. By clamping leads of the lead frame in separate sets, the machine provides improved clamping for lead frames with leads requiring clamping in different planes.
摘要:
The method for hermetically encapsulating microsystems in situ consists, in a first phase, of mounting on a common substrate (1), several microsystems (6) surrounded by a metal adhesion layer (4) deposited on the substrate (1). In a second phase, in a common deposition step a first metal layer (7) is deposited by electrolytic means on each microsystem (6) and on an annular zone (7a) of the adhesion layer (4) surrounding each microsystem (6), so as to completely cover each microsystem by overlap. Subsequently a second metal layer (9) is deposited by electrolytic means on the first metal layer (7) and on the adhesion layer so as to cover most of the first layer with the exception of at least one passage (10) per microsystem (6), providing access to the first layer (7). The metal of the first layer is different from the metals of the adhesion layer, the second layer and the microsystem. The first layer (7) is removed by selective chemical etching through the passages (10) which are closed to obtain metal capsules hermetically enclosing each microsystem.