International Business Machines Corporation

Brian L Robertson

Kenneth Skene Murray

Stuart P Lees

William French

Colin David McCall

John Joseph Garrity

Alexander Boyd

Peter Gallagher

Alan P Downie

Frank John Martin

James Andrew McNee

John Brown

Solder particles,are deposited onto metallized contacts of a direct chip attach (DCA) site located on a substrate,. The contacts,are coated with a layer of flux,. A pick up head,is positioned in a reservoir,of solder particles,and particles are attracted to the apertures in the end,of the head. The apertures have an arrangement corresponding to the footprint of the metallized contacts on the substrate. The head,is positioned adjacent the substrate,and the particles,released. The particles,stick to the flux,coated on the contacts,. The particles are reflowed, leveled and again coated with flux. An integrated circuit chip is then placed on the leveled reliefs,and the reliefs reflowed again to attach the chip onto the contacts

Solder particle deposition

A tool for soldering pin-in-hole electronic circuit components includes a tool plate with a set of via holes corresponding to the holes of a circuit board on which a circuit component is soldered. The board is aligned with the tool plate and hot gas is supplied through the set of plate vias to reflow solder in the board holes. The tool is particularly suitable for use in removing and replacing pinned circuit components. Use of particular gases (e.g., nitrogen) allows soldering to be carried out without the use of flux. Advantages of the tool are that it prevents burning the circuit board and/or unintentionally reflowing other circuit components mounted on the board (by directing hot gas only substantially onto the circuit board's solder-containing holes).

Solder apparatus and method

A method for increasing the strength of a solder joint between a nickel-iron lead frame of an electronic circuit module and a copper pad of a printed circuit board on which the module is mounted includes baking the joint for at least one hour at a temperature in the range 373K to 456K. The baking step is found to significantly increase the strength of the joint.

Method for strengthening a solder joint when attaching integrated

Solder particles 220 are deposited onto metallized contacts of a direct chip attach (DCA) site located on a substrate 301. The contacts 302 are coated with a layer of flux 303. A pick up head 211 is positioned in a reservoir 201 of solder particles 220 and particles are attracted to the apertures in the end 213 of the head. The apertures have an arrangement corresponding to the footprint of the metallized contacts on the substrate. The head 211 is positioned adjacent the substrate 301 and the particles 220 released. The particles 220 stick to the flux 303 coated on the contacts 302. The particles are reflowed, leveled and again coated with flux. An integrated circuit chip is then placed on the leveled reliefs 501 and the reliefs reflowed again to attach the chip onto the contacts 302.

A direct chip attach module (DCAM) 10, comprises of one or more electronic components 30, electrically bonded to a printed circuit 40, on a substrate 20. The DCAM 10, is bonded to an electronic circuit assembly by connection pads 50, formed on the edge of the DCAM substrate 10. This enables easy visual inspection of solder joints between the DCAM and the assembly. DCAM substrates 10, are initially formed in a panel form 70, and vias 50, are drilled and filled with electrically conductive media 55, at predetermined connection points. The DCAM 10, is then excised from the parent panel 70, and the cut vias provide connection pads 55, along the edge of the substrate 10.

Method of manufacturing a circuit module

Module having vertical peripheral edge connection

Solder is deposited on a printed circuit board by melting the solder in a container. The container has a slot for passage of solder, therethrough and control means actuable to alternately allow and prevent passage of solder through the slot. The slot is placed in contact with a stencil and the control means is actuated to allow passage of solder through the slot. The stencil is moved relative to the container in a direction transverse of the slot to deposit solder on the printed circuit board via the stencil.

Growing community of inventors

Gourock, United Kingdom

Brian L Robertson