Mask and solder form
AssigneeHughes Aircraft Company
InventorJohn W. Jamison
Life of this patent
Estimating the term…
Abstract
A mask and solder form for mounting of multi-leaded integrated circuit carriers to printed wiring boards during a soldering process is disclosed. The form comprises a multi-layer composite frame-like structure. The top layer is a translucent sheet, and is provided with a solder and flux strip. The top layer is bonded to a divider layer which is slotted to accept the multi-wire leads of the circuit carrier. The bottom surface of the divider layer is coated with adhesive. The transparent top layer permits precise alignment of the leads of the carrier and the printed wiring board lines. The divider layer blocks the flow of molten solder between leads by providing each wire with its own individual slot. The form is well suited to production loading of the circuit carriers on the printed wiring boards for vapor phase soldering.
Claims9
A mask and solder form for securing a rectangular multi-leaded integrated circuit carrier device against corresponding printed lines on a printed wiring board during a soldering process, comprising:
- a rectangular frame structure adapted to enclose the periphery of the carrier device and engage against the leads of the carrier device, said structure comprising:
- a rectangular, open center top layer made of translucent polymer sheet material adapted to withstand the temperatures sustained during a soldering process, said open center being defined by an inner edge spaced wider than the carrier device, said top layer having a bottom surface;
- a solder strip disposed along the bottom surface of said top layer adjacent said inner edge and parallel to said inner edge;
- an adhesive layer under said solder strip and on the bottom surface of said top layer;
- a rectangular, open center divider layer adhesively attached under said top layer and under said solder strip, said divider layer having an inner edge substantially in alignment with said inner edge of said top layer, said divider layer comprising a sheet of polymer material adapted to withstand the temperatures sustained during the soldering process, said divider layer having a thickness at least equal to the thickness of the leads on the carrier device, said divider layer having walls defining a plurality of slots extending to said inner edge of said divider layer adjacent the periphery of the carrier device in visually confirmable spatial correspondence with the lead pattern of the carrier device, each of said slots being arranged to accept a corresponding lead;
- and
- a coating of pressure-sensitive adhesive applied to the lower surface of said divider layer to hold said mask and the carrier leads in place on the printed wiring board.
An apparatus for securing the leads of a multi-leaded circuit carrier device against the printed wire lines on a printed wire board for soldering, comprising:
- a divider layer for positioning at the edge of the carrier device, said divider layer having an edge and having walls defining a plurality of slots extending to the edge of said divider layer for fitting over the leads and receiving the leads in the open ends of the individual segregated slots, said divider layer being at least as thick as the thickness of the leads;
- a solder strip positioned on the top of said divider layer and extending across said slot for providing a predetermined amount of solder at each individual segregated slot;
- a translucent cover layer over said divider layer and over said solder strip;
- an adhesive under said cover layer and under said solder strip and over each said slot for releasably securing said leads in individual slots and visibly maintaining said slots in correspondence with the printed wiring lines during a solder process to allow said solder to flow between the respective leads and corresponding printed wire lines, said divider layer between said slots preventing the flow of molten solder between adjacent leads of said carrier device during soldering.
The method of masking and soldering the lead on an integrated circuit carrier onto a corresponding printed line on a printed circuit board comprising the steps of:
- forming a covered slot having a width suitable to receive the lead and to extend at least partway across the width of the printed line on the printed circuit board, having a length suitable to receive the line in the open end thereof and having a height at least as high as the thickness of the lead with solder in the slot, adhesive in the slot for retaining the lead in the slot, having adhesive on the bottom of the form for releasable attachment to the printed circuit board and a translucent covering over the slot comprising the steps of:
- observing the lead through the translucent cover of the slot;
- shifting the form with respect to the lead to visually align the lead with the slot;
- attaching the lead into the slot by means of adhesive in the slot;
- visually observing the position of the lead with the corresponding printed wire pattern;
- aligning the lead with the corresponding printed wire pattern;
- and
- attaching the form to be printed wiring board by means of the adhesive on the bottom of the form with the lead in alignment with the printed line on the printed wiring board.
Dependencies are inferred from the claim text.