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Method to improve burr issue on dimple lead singulation

IP.com Disclosure Number: IPCOM000236446D
Publication Date: 2014-Apr-25
Document File: 3 page(s) / 559K

Publishing Venue

The IP.com Prior Art Database

Abstract

Due to design limitation, the side wall of current xQFN is the copper after Singulation Saw, which is not Tin wettable during SMT. So dimple was design on the lead which can make Tin wettable during SMT. However, during singulation process, too much heat caused burrs left in the dimple after singulation saw. It will impact on inspection effect in customer site. This method can help to improve burr issue on dimple lead singulation.

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Method to improve burr issue on dimple lead singulation

Abstract

Due to design limitation, the side wall of current xQFN is the copper after Singulation Saw, which is not Tin wettable during SMT. So dimple was design on the lead which can make Tin wettable during SMT.

However, during singulation process, too much heat caused burrs left in the dimple after singulation saw. It will impact on inspection effect in customer site.

This method can help to improve burr issue on dimple lead singulation.

Introduction

Due to design limitation, the side wall of current xQFN is the copper after Singulation Saw, which is not Tin wettable during SMT. So dimple was design on the lead which can make Tin wettable during SMT.

However, during singulation process, too much heat caused burrs left in the dimple after singulation saw. It will impact on inspection effect in customer site.

Below, we present a method for preventing these issues from occurring.

The method will keep dimple on lead; keep current process flow; move leads clockwise for each edge of units, so two units’ leads will stagger to each other. In singulation process, this kind of lead design is good at heat dissipation and blade self-sharpening. And then solve burr issue on dimple part.

Design and Implementation

Figure 1 shows the comparison of current LF design and new LF design.  

 
 

Figure 1.  Comparison of current LF design and new LF design

 
 

Figure 2.  Comparison of heat generation and burr issue performance

 
Figure 2 shows t...