Browse Prior Art Database

DIE FACE DECOUPLING CAPACITOR SYSTEMS

IP.com Disclosure Number: IPCOM000007857D
Original Publication Date: 1996-Nov-01
Included in the Prior Art Database: 2002-Apr-30
Document File: 7 page(s) / 213K

Publishing Venue

Motorola

Related People

Leo Higgins: AUTHOR

Abstract

Positioning a source of decoupling capacitance very close to the input,and outputs of an integrated circuit (IC) is very desirable since it minimizes the parasitics, especially the inductance, of the intercon- nect linking the capacitance to the IC. The use of discrete multilayer ceramic capacitors is most com- mon, but it is ohen difficult to locate these devices as close to the IC as desired. It is becoming increas- ingly common to build capacitance into the interconnection substrate to which the IC is con- nected. Ohen this is not ideal since the level ofcapac- itance attained is inadequate or the parasitics ofthe interconnect from the IC to the capacitance is high enough to reduce the effectiveness of the capaci- tance for decoupling or local power supply.

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Page 1 of 7

M-LA Technical Developments

DIE FACE DECOUPLING CAPACITOR SYSTEMS

by Leo Higgins

  Positioning a source of decoupling capacitance very close to the input,and outputs of an integrated circuit (IC) is very desirable since it minimizes the parasitics, especially the inductance, of the intercon- nect linking the capacitance to the IC. The use of discrete multilayer ceramic capacitors is most com- mon, but it is ohen difficult to locate these devices as close to the IC as desired. It is becoming increas- ingly common to build capacitance into the interconnection substrate to which the IC is con- nected. Ohen this is not ideal since the level ofcapac- itance attained is inadequate or the parasitics ofthe interconnect from the IC to the capacitance is high enough to reduce the effectiveness of the capaci- tance for decoupling or local power supply.

  There are a number of possible means for connecting a variety of capacitor configurations directly to the electrical contacts on an IC, and sev-

eral are illustrated here. Means to provide an air gap between the die face and the capacitor are shown (Fig. 1 and 2). This air gap will reduce the possibil- ity of adding parasitic capacitance to the IC. Exten- sion of tape automated bonding (TAB) lead frame structures provides the means to decouple one or more voltage supplies (Fig. 1, 2,3, 5, 6). In another configuration means to provide decoupling for more than one voltage supply with a die face capacitor is shown (Fig. 1,3,4,5,6).

  It is becoming quite common for ICs to have large power supply buses on the die face surface. Another die face capacitor configuration shows a capacitor structure which utilizes the die face volt- age buses as one of the electrodes ofa die face paral- lel plate capacitor which may provide decoupling for one or more voltage supplies (Fig. 5).

0 Motorola, 1°C. ,996 43 November 1996

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Page 2 of 7

6% M-LA Technical Developments

SEPARATE CAPtClTOR ELEMENT

Vi. electrode (Cu foil)

/

Air, adhesive, or Fig. IA: (SIDE VIEW)

Fig. 1 (A#) Capacitor for Multivoltage Decoupling

2 Ground lead

Signal lead

\

\ VI lead

Fig. 1 B: (Top View Partial Section)

0 Mrm'ola, Inc. ,996

44 November1996

[This page contains 15 pictures or other non-text objects]

Page 3 of 7

M-LA Technical Developments

Tab-like leads (could be continuous foil elements)

Paral...