Browse Prior Art Database

Extensions of Terminal Metal Geometries

IP.com Disclosure Number: IPCOM000101741D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Cook, HC: AUTHOR [+3]

Abstract

Methods for extending current solder ball terminal metal technology by evaporating metal through a mask are disclosed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Extensions of Terminal Metal Geometries

       Methods for extending current solder ball terminal metal
technology by evaporating metal through a mask are disclosed.

      One method utilizes photolithography techniques where the mask
is fabricated utilizing a dry resist film, or any other readily
applied photoactive material, laminated to an appropriate support
material, e.g., molybdenum, stainless steel. The photoactive material
is then exposed through an appropriate mask, developed and hardened.
The rigid laminated mask is then ready for use in a manufacturing
environment.

      Referring to Fig. 1a, a portion of the support structure is
shown to which a dry resist film is laminated (Fig. 1b), and covered
on top with a protective mylar film. Next, an appropriate mask is
placed on top of the structure (Fig. 1c), and exposed with a
ultraviolet (UV) light source. After the exposure, the mylar is
removed, the resist is developed, and the laminated structure is
baked to form a rigid terminal metal mask. The mask is used face
down, (Fig. 1d), providing a thin structure in the area of terminal
metal which allows fine geometries to be fabricated.

      A second method for extending the current terminal metal
technology utilizes electro-discharge machining (EDM) or
electro-chemical machining (ECM) or ultrasonic machining (USM) to
form a reinforced mask structure. The mask is constructed of a
material with a coefficient of thermal expansion closely matched to
t...