Browse Prior Art Database

SURFACE MOUNT PACKAGE ADHESION IMPROVEMENT

IP.com Disclosure Number: IPCOM000006465D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2002-Jan-07
Document File: 1 page(s) / 54K

Publishing Venue

Motorola

Related People

Bill Miller: AUTHOR [+3]

Abstract

Surface mount devices are typically mounted to printed circuit boards using automated equipment. The plastic package is located on the PC board and often a polymer adhesive, such as epoxy, is used to attach the package to the board prior to and during the actual soldering operation.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 68% of the total text.

Page 1 of 1

0 M

MOTOROLA INC. Technical Developments Volume 15 May 1992

SURFACE MOUNT PACKAGE ADHESION IMPROVEMENT

by Bill Miller, Bill Taylor and Scott Chang

  Surface mount devices are typically mounted to printed circuit boards using automated equipment. The plastic package is located on the PC board and often a polymer adhesive, such as epoxy, is used to attach the package to the board prior to and during the actual soldering operation.

  When these adhesives are used, the strength and reliability of the adhesive bond is strongly dependent on the surface cleanliness of the package. Typical molded packages have "mold release" wax on the surface to enhance ejecting of the molded parts from the mold. This wax on the surface causes very poor adhesion using normal epoxies.

  To ensure good adhesion to the PC board cleaning methods such as vapor degreasers have been used that are expensive as well as environmentally unacceptable. The hydrogen flame cleaning method uses a hydrogen or hydrogen oxygen flame to remove surface impuri- ties. The flame is quickly passed over the surface of the plastic package body causing contaminants, such as mold release wax, to be burned off. This brief exposure to the

high temperature flame causes no detrimental effects on the plastic package and produces a clean surface suita- ble for marking or bonding down to a printed circuit board.

  Typical molded parts were tested to document their properties with respect to adhesion. The two methods used were a s...