Browse Prior Art Database

Ternary Solvent System

IP.com Disclosure Number: IPCOM000080957D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Fugardi, J: AUTHOR [+2]

Abstract

A final topseal coating composition for modules having semiconductor chips located thereon, consists of a polyamide-imide resin dissolved in a single solvent. By combining a unique blend of solvents in the ratio of 5% low-vapor pressure, acetanilide; 60% intermediate-vapor pressure, N-methyl pyrrolidone; 30% high-vapor pressure, acetone and 5% polymer, a film with superior leveling properties to a one-solvent system is obtainable. The topseal coating is flowed onto the module which has a spray applied coat of the polyamide-imide resin thereon. The specific characteristics which show improvement as compared to the single-solvent system are: (1) No ripples visible in the polymer coating radiating out from the semiconductor chip.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 91% of the total text.

Page 1 of 1

Ternary Solvent System

A final topseal coating composition for modules having semiconductor chips located thereon, consists of a polyamide-imide resin dissolved in a single solvent. By combining a unique blend of solvents in the ratio of 5% low-vapor pressure, acetanilide; 60% intermediate-vapor pressure, N-methyl pyrrolidone; 30% high-vapor pressure, acetone and 5% polymer, a film with superior leveling properties to a one-solvent system is obtainable. The topseal coating is flowed onto the module which has a spray applied coat of the polyamide-imide resin thereon. The specific characteristics which show improvement as compared to the single-solvent system are:
(1) No ripples visible in the polymer coating radiating out

from the semiconductor chip.
(2) Thickness coverage at the inner module pin pad locations

is significantly increased and equal to the outer pin pads.
(3) Pin hole defects located on lines under the chip are

covered.
(4) Cross-section thickness measurements show a uniform coverage

around the solder reflow flip-chip pad connection.
(5) Thermal cycle testing of chip connections indicates that

the presence of the coating enhances the fatigue properties

of the soldered joint.
(6) The toxicity concentration of the solvent vapors is less

than the single solvent using dimethyl acetamide.

The improvement lies in the percentage of the low-vapor pressure component. At 3 1/2%, defects were not covered under the chip and at 2% ripples were seen. Increasing th...