Browse Prior Art Database

SELF LOCATING CENTER MOUNT QUAD FLAT PACK IC PACKAGE

IP.com Disclosure Number: IPCOM000007022D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2002-Feb-19
Document File: 3 page(s) / 119K

Publishing Venue

Motorola

Related People

G. Limia: AUTHOR [+3]

Abstract

With the ongoing quest for best in class manu- facturing and the need to both reduce cycle time and improve quality we are continually faced with the need to increase the probability of accurate com- ponent placement without vision. Utilizing the design for the self locating center mount quad flat pack assures secure retention of the IC in its location, resulting in a reduction of defects horn misalignment from impact trauma. This also expands the capabil- ity for tape and reel packaging due to central loca- tion of leads rather than extensions below bottom surface of the IC.

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MOTOROLA INC. Technical Developments Volume 20 October 1993

SELF LOCATING CENTER MOUNT QUAD FLAT PACK IC PACKAGE

by G. Limia, D. Tribbey and A. Hertz

  With the ongoing quest for best in class manu- facturing and the need to both reduce cycle time and improve quality we are continually faced with the need to increase the probability of accurate com- ponent placement without vision. Utilizing the design for the self locating center mount quad flat pack assures secure retention of the IC in its location, resulting in a reduction of defects horn misalignment from impact trauma. This also expands the capabil- ity for tape and reel packaging due to central loca- tion of leads rather than extensions below bottom

surface of the IC.

  Currently the placement of surface mount QFP integrated components on circuit bearing substrates is done robotically, with vision, from tray or tube packaging (Plgure 1). The component placement and the retention in place during transport of the sub- strate from assembly stations to the reflow system is highly critical and subject to minor mislocation of the device even after accurate placement.

Conventional Method of QFP Location

Solder


.^""^"+i^.. QFP IC Package

L

I Printed Circuit Soard

Figure 1

  It was required to develop a means of positive location during the placement of Quad Flat Pack IC packages and their retention of this location during subsequent transportation ofthe printed circuit board assemblies through the reflow process.

This can be accomplished by the generation ofa

series of semi-circles, in the footprint of the IC leads, produced by first drilling the lead pattern through the PCB lamin...