Browse Prior Art Database

Heat Sink Locking Feature And Electrical Enhancement for Plastics Package With Heat Sink/Heat Spreader

IP.com Disclosure Number: IPCOM000201495D
Publication Date: 2010-Nov-12
Document File: 6 page(s) / 259K

Publishing Venue

The IP.com Prior Art Database

Abstract

Significantly increase heat transfer efficiency; more precise heat sink placement; improve self inductance for input output (IO) pins and reduce return path for Power Distribution Network (PDN) pins by the following means:- 1. Lead frame die attach paddle bottom is chemically half etched to form dimples. 2. Heat sink with protrusion design is attached to pre-applied thermally & electrically conductive epoxy on lead frame die attach paddle (DAP) dimples. The protrusion location is match to the half etched dimples position. 3. Heat sink size is extended until lead finger bottom area & act as a ground plane through Voltage Sink (VSS) wire downbond to DAP

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 59% of the total text.

Heat Sink Locking Feature And Electrical Enhancement for Plastics Package With Heat Sink/Heat Spreader

Summarize the invention in the following provided space:

Significantly increase heat transfer efficiency; more precise heat sink placement; improve self inductance for input output (IO) pins and reduce return path for Power Distribution Network (PDN) pins by the following means:-

1. Lead frame die attach paddle bottom is chemically half etched to form dimples.

2. Heat sink with protrusion design is attached to pre-applied thermally & electrically conductive epoxy on lead frame die attach paddle (DAP) dimples. The protrusion location is match to the half etched dimples position.

3. Heat sink size is extended until lead finger bottom area & act as a ground plane through Voltage Sink (VSS) wire downbond to DAP

3.      Gull shaped heat sink design reduces the distance between lead fingers and heat sink.

4.      The nearest the lead finger to reference ground plane provide good return path for IO.

5.      Leadframe IO lead finger behave like traces that enable the control of impedance to desired target. 

Summarize what has been done before in the following provided space:

Conceptual study and layout

Manufacturability study

Describe the problem(s) you are trying to solve in the following provided space:

The heat dissipation performance of drop in heat sink/heat spreader plastic packages is circumscribed by the mold compound resin interval between dropped in heat sink/heat spreader and die attach paddle bottom. Drop in heat sink/heat spreader does not have position locking feature, certain offset of heat sink placement will cause cosmetically deficiency in which the package might experience partial heat sink exposed.

IO pins rely on neighboring grounded interconnect for least inductance, there is no ground plane reside at the bottom of lead finger. Thus higher mutual inductance was generated due to signal coupling of IO pins rely on longer return path for mutual inductance reduction.

Summarize the advantage(s) and/or value(s) in the following provided space:

Improve heat dissipation of the package.

Improve the whole electrical performance of a package.

Increase assembly yield by eliminating exposed heat sink cosmetically defect.

 

Attach a detail description of the invention, the description should:

a.                   Describe how the prior art works;

Heat sink/heat spreader is encapsulated into the package by using epoxy molding compound. Figure 1 shows the package construction:

Figure 1 Prior ar...