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A composition and method for removing silicone oils, greases, gels or organic epoxies is described.
English (United States)
This text was extracted from a PDF file.
This is the abbreviated version, containing approximately
92% of the total text.
Page 1 of 1
Nondestructive Chemical Removal of Encapsulants used in Semiconductor
A composition and method for removing silicone oils, greases, gels or
organic epoxies is described.
In certain configurations of semiconductor chip packages organic epoxies,
such as SCOTCHCAST* 5239 are used for edge sealing, and silicone gels, such
as SYLGARDT* are used as top seals. Often it is necessary to remove these
materials to rework the chip or substrate. The removal must be accomplished
without damage to the components of the chip and packaging material.
Unfortunately, many solvents for epoxies and silicone materials also damage
polyimide materials which are used in the manufacture of the module
It has been found that a solvent having about 95% by volume n-butylamine
and about 5% by volume of oleic acid is an excellent solvent for silicone oils,
greases and gels, especially SYLGARD, and also for organic epoxies, especially
SCOTCHCAST 5239, and will not damage polyimide resins or other components
of a silicon semiconductor package.
A preferred method of using the solvent is to place the solvent in a reflux
system heated to about 78 degrees C and immerse the module in the solvent for
about 1 to 3 hours. The module is then cooled in the reflux system to about room
temperature. This will essentially remove all the silicone and epoxy material.
Following the solvent treatment, the modules are immersed in toluene for
about 5 minutes and thereafter in isopropanol for abo...