Browse Prior Art Database

Double-Density Memory Carrier

IP.com Disclosure Number: IPCOM000036672D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Gruber, HW: AUTHOR [+4]

Abstract

A ceramic chip carrier 1 is proposed whose storage density is doubled by placing memory chips 2 on its top and bottom sides.

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Double-Density Memory Carrier

A ceramic chip carrier 1 is proposed whose storage density is doubled by placing memory chips 2 on its top and bottom sides.

For this purpose, ceramic chip carrier 1 is provided with holes by means of a laser. Then, the carrier, including its cylindrical hole walls, is metallized by vapor depositing a chromium and a copper layer. This metallization is provided with an additional copper layer by electroplating. After carrier 1 has been cleaned, a resist foil is laminated to its top and bottom sides, and both sides are photolithographically provided with a conductor structure by subtractive etching. In the next step, chips 2 and decoupling capacitors 3 are placed on either side of the ceramic carrier, soldering the chips by flip- chip technology. Soldering is effected by an infrared device which heats up chips 2 and decoupling capacitors 3 only briefly. Standard chips 4 with integrated tin solder and flux are used as contacts to connect the ceramic chip carrier to a memory card. As a result, only one reflow step is necessary for soldering all chips 4 to carrier 1. Finally, the entire structure is embedded in plastic 5.

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