1255results about How to "Improve joint strength" patented technology

A lead frame comprising a frame which defines a central opening. Disposed within the central opening is a die pad which is connected to the frame. Also connected to the frame are a plurality of leads which extend within the opening toward the die pad. Each of the leads defines opposed top and bottom surfaces, an inner end, an outer end, and an opposed pair of side surfaces. The bottom surface and the outer end collectively define a corner region of the lead. Formed within the corner region is a recess which is sized and configured to accommodate the flow of reflow solder thereinto.

In a structure of a semiconductor device, a Si chip and a metal leadframe are jointed by metallic bond via a porous joint layer made of high conductive metal, having a three-dimensional network structure and using Ag as a bonding material, and a film containing Zn oxide or Al oxide is formed on a surface of a semiconductor assembly contacting to a polymer resin. In this manner, by the joint with the joint layer having the porous structure mainly made of Ag, thermal stress load of the Si chip can be reduced, and fatigue life of the joint layer itself can be improved. Besides, since adhesion of the polymer resin to the film can be enhanced by the anchor effect, occurrence of cracks in a bonding portion can be prevented, so that a highly-reliable Pb-free semiconductor device can be provided.

A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

Provided is a spot welded joint (10) which includes at least one thin steel plate with a tensile strength of 750 MPa to 1850 MPa and a carbon equivalent Ceq of equal to or more than 0.22 mass % to 0.55 mass % and in which a nugget (3) is formed in an interface of the thin steel plates (1A, 1B). In a nugget outer layer zone, a microstructure consists of a dendrite structure in which an average value of arm intervals is equal to or less than 12 μm, an average grain diameter of carbides contained in the microstructure is 5 nm to 100 nm, and a number density of carbides is equal to or more than 2×10⁶/mm².

In accordance with the invention, bodies of materials are joined by disposing between them a reactive multilayer foil and one or more layers of meltable joining material such as braze or solder. The bodies are pressed together against the foil and joining material, and the foil is ignited to melt the joining material. The pressing is near the critical pressure and typically produces a joint having a strength of at least 70-85% the maximum strength producible at practical maximum pressures. Thus for example, reactively formed stainless steel soldered joints that were heretofore made at an applied pressure of about 100 MPa can be made with substantially the same strength at a critical applied pressure of about 10 kPa. Advantages of the process include minimization of braze or solder extrusion and reduced equipment and processing costs, especially in the joining of large bodies.

The present invention relates to a rubber crawler including: a joint formed by joining together opposite ends of a crawler body comprising an elastic member shaped like a belt having the opposite ends; and lugs projected at predetermined space intervals along a longitudinal direction of the belt and arranged on an outer circumferential surface of the crawler body. The joint is disposed on the outer circumferential surface of the crawler body, as located in a ground non-engaging portion and at different positions with respect to the longitudinal direction of the belt, the ground non-engaging portion defining an area excluding the lugs. In this way, stress acting on the joint is distributed or reduced.

Disclosed is a package-on-package semiconductor device comprising a bottom package, a top package thereon and a ACA (Anisotropic Conductive Adhesive) layer. A plurality of ball pads are disposed on the peripheries of an upper surface of the substrate of the bottom package. A plurality of solder balls are disposed at the peripheries of the lower surface of the substrate of the top package. The ACA layer having a central opening is interposed between the bottom package and the top package where the ACA layer contains a plurality of conductive particles. Therein, the size of the central opening and the thickness of the ACA layer are selected such that the anisotropic conductive adhesive layer adheres the peripheries of the upper surface of the bottom package to the peripheries of the lower surface of the top package and the solder balls are encapsulated inside the anisotropic conductive adhesive layer. The solder balls encapsulate some of the conductive particles to mechanically joint and electrically connect to the ball pads. Thereby, the bonding strength of the solder balls can be improved and the warpage of the substrate of the bottom package is effectively reduced to avoid failure of electrical connections between both packages caused by the breaking of soldering joints.

A lead frame adapted to a semiconductor package, which is enclosed in a molded resin body and is connected with a board, is formed by processing a thin metal plate so as to include a stage for mounting a semiconductor chip thereon, a plurality of leads arranged to encompass the stage, and a plurality of lead interconnecting members (or dam bars) for interconnecting the leads together. At least one recess, which is of a circular shape or a non-circular shape, is formed on the backside of the lead (or the lead interconnecting member), which is substantially arranged in the same plane with a terminal surface of the molded resin body. Due to the formation of the recess that is subjected to plating, it is possible to increase the joining strength between the lead and solder; hence, it is possible to improve reliability regarding electric connection between the semiconductor package and board.

The invention provides an aluminium nitride ceramic copper-clad substrate which comprises an aluminium nitride ceramic chip, and a copper foil coated on at least one surface of the aluminium nitride ceramic chip, wherein a metal modification layer is formed between the ceramic chip and the copper foil, and the metal modification layer comprises Cu2O, CuAlO2 and a set of compound selected from the following two set of compounds: (1) TixNy and TiO2 wherein x/y is 0.25 to 1; (2) MnO2. In addition, the invention also provides a preparation method of aluminium nitride ceramic copper-clad substrate. In the invention, with a magnetron sputtering method, a metal mixture coating is formed on the surface of the dense sintering of the aluminium nitride ceramic chip, as the dense sintering of the metal mixture coating through high temperature sintering, the formed metal modification layer can improve the surface of the aluminium nitride ceramics chip and forms a good bonding with the copper foil.

In a first step, friction stir welding is performed, while supplying a filler into a joining portion, in order to prevent the coarsening of crystal grains of metal materials in a subsequent fusion processing. Then, a fusion processing such as MIG welding is performed. The filler to be added to the joining portion includes a substance that does not chemically react with the metal materials and has a melting point higher than a melting point of the metal materials and a substance in which a misfit with the metal materials is within ±15%. As a result, the coarsening of crystal grains by the fusion processing is inhibited and the joint strength can be increased.

An improved structure of a spark plug is provided to ensure a high strength of joint between a ground electrode and a metal shell. The ground electrode is resistance-welded to the metal shell so that it is embedded partially in an end surface of the metal shell to create a weld interface extending from the end surface to an inner periphery of the metal shell, thus resulting in an increased size of the weld interface to increase the joint strength. The resistance welding keeps the temperature of a weld between the ground electrode and the metal shell at a lower level during welding as compared with laser welding, thus minimizing solidification cracking in the weld.

In joining an Fe-based metallic member comprising an Fe-based material and an Al-based metallic member comprising an Al-based material by a Zn-based brazing filler metal, a joined part of the Fe-based metallic member is heated at a temperature higher than a melting point of the Fe-based material.

A QFN package with improved joint solder thickness for improved second level attachment fatigue life. The copper leadframe of a QFN chip carrier is provided with rounded protrusions in both the chip attach pad region and the surrounding lead regions before second level attachment. The rounded stand-off protrusions are formed from the copper itself of the copper of the leadframe. This may be achieved by punching dimples into one surface of the copper plate of the leadframe before plating to form protrusions on the opposing surface. This method of forming the rounded protrusions simplifies the process of forming stand-offs. The protrusions provide a structure that increases wetting area and allows the use of a larger quantity of solder for increased solder joint thickness and better die paddle solder joint area coverage. As a result of the increased solder joint thickness, second level fatigue life is significantly improved. As a result of the improved die paddle solder joint area coverage, improved thermal performance of the chip carrier is also significantly improved.