Browse Prior Art Database

RECESSED IC SUBSTRATE FOR TUNING PAD CONTAINMENT

IP.com Disclosure Number: IPCOM000006187D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2001-Dec-12
Document File: 2 page(s) / 77K

Publishing Venue

Motorola

Related People

David A. Tribbey: AUTHOR [+2]

Abstract

This paper and the following sketches describe a unique means for containment of IC tuning pads with- out reflow interference. The outputs of various IC's are drifting during the current packaging process. To increase yields, the IC's may be tuned subsequent to the packaging process. In order to tune these It's, additional pads (figure 3) on the substrate surface are required. These pads must not contact PC board run- ners or have the opportunity to short to the printed wiring board during reflow. The present method of insulating these pads requires a 2-4 mil thick material such as polyimide pressure sensitive tape (figure 1) on the underside of the IC substrate. This means of electri- cal insulation could inhibit proper reflow characteristics.

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0 M

MOTOROLA INC. 1,

Technical Developments

July 1991

Pume l3

RECESSED IC SUBSTRATE FOd

TUNING PAD CONTAINMENT ~,

by David A. Tribbey and Allen David He&

  This paper and the following sketches describe a unique means for containment of IC tuning pads with- out reflow interference. The outputs of various IC's

are drifting during the current packaging process. To increase yields, the IC's may be tuned subsequent to the packaging process. In order to tune these It's, additional pads (figure 3) on the substrate surface are required. These pads must not contact PC board run- ners or have the opportunity to short to the printed wiring board during reflow. The present method of insulating these pads requires a 2-4 mil thick material such as polyimide pressure sensitive tape (figure 1) on the underside of the IC substrate. This means of electri- cal insulation could inhibit proper reflow characteristics.

It is desirable to maintain a flush reflow surface on the underside of the IC to allow for proper reflow

and IC seating. If the area of interest (figure 2) was to be recessed 3-5 mils, this, would act as a reservoir for either the above-mentioned tape or any other insulat- ing material placed or di sP

  A means to accomp rli: ceramic blanks with a I ,elc of the tuning pads that a rk ing a recess in the ceral "i can be tuned after packr I;: filled with a non-condum cii the pads to avoid shorts.

tensed into this area.

sh this would be to prepare :essed area for containment de...