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Full Exposed Pad Package Design

IP.com Disclosure Number: IPCOM000245247D
Publication Date: 2016-Feb-22
Document File: 4 page(s) / 155K

Publishing Venue

The IP.com Prior Art Database

Abstract

In some cases, especially for power devices, a semiconductor package can't meet its thermal requirement for device performance, even though it already has an Exposed Pad (EP) package design because the EP area is not big enough, as shown in Figure 1. We found that there is some room to improve the thermal performance by increasing the EP area, which only requires some lead frame modification. We can turn package bottom side to full EP area, which significantly improves the package thermal dissipation capability.

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Full Exposed Pad Package Design

Abstract: 

In some cases, especially for power devices, a semiconductor package can’t meet its thermal requirement for device performance, even though it already has an Exposed Pad (EP) package design because the EP area is not big enough, as shown in Figure 1.  We found that there is some room to improve the thermal performance by increasing the EP area, which only requires some lead frame modification.  We can turn package bottom side to full EP area, which significantly improves the package thermal dissipation capability.

                        Figure 1 – conventional package design

Body:   

  1. Lead frame (LF) design improvement: we add two sided thermal pads to extend EP area, as shown in Figure 2.

                                                            Figure 2 – modified lead frame design

 

  1. After molding, bend down two side thermal pads, they will turn into good path for thermal dissipation.

Due to two sides of thermal pads will solder together with center EP area through PCB pad design, such thermal  dissipation path will be very efficiency.

Since EP area increase 2X-3X; so in theory, thermal dissipation capability will enhance to 1.5X- 3X than before.

Conclusion

The modified lead frame design allows for a package with a full exposed pad to be assembled, which provides greater area for thermal dissipation and thus improved thermal performance.

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