International Business Machines Corporation

Kenneth Skene Murray

Brian L Robertson

Stuart P Lees

William French

Colin David McCall

Alexander Boyd

James Andrew McNee

John Brown

Briand L Robertson

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

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.

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.

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Inverkep, United Kingdom

Kenneth Skene Murray