CLAMPING SYSTEM FOR SIP WIRE BOND

Publishing Venue

Motorola

Related People

Abstract

Too many failures in post bonding wire pull and peel tests due to inconsistent clamping of leadframes during bond- ing procedure. Any new designs are made difficult by space limitations and the awkward position of corner leads. The Solution Very firm and consistent lead clamping is accomplished by using a new clamping structure, portions of which are illustrated in FIG 1. The new clamping system includes individual spring finger clamps with knife edge contact pressure as shown by the side view of FIG. 2. This improved clamping results in good post-bonding, achieving wire pull Cpk >1.5 and 100% peel test acceptance.

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MOlYlROlA Technical Developments Volume 10 March 1990

CLAMPING SYSTEM FOR SIP WIRE BOND

by Chan Mun Leong and Harris Fung

The Problem

   Too many failures in post bonding wire pull and peel tests due to inconsistent clamping of leadframes during bond- ing procedure. Any new designs are made difficult by space limitations and the awkward position of corner leads. The Solution

   Very firm and consistent lead clamping is accomplished by using a new clamping structure, portions of which are illustrated in FIG 1. The new clamping system includes individual spring finger clamps with knife edge contact pressure as shown by the side view of FIG. 2. This improved clamping results in good post-bonding, achieving wire pull Cpk >1.5 and 100% peel test acceptance.

The new clamping system is shown mounted in an SIP wire bonder in FIG. 3. The design of the new clamping structure includes the following concepts:

3 pcs clamping, with bottom shelf slider and sensor/pneumatic control individual finger clamping for all leads
spring action in each finger
clamping occurs as near to bond head as possible without obstructing bond head knife edge contact
specific spots are selected at top and bottom of the leads for contact by clamp, point pressure incresses by minimiz- ing contact area
fine Z-axis motion adjustment
extended design for corner leads
slider shelf contains reliefs for minimum contact area

Figure 1

0 Motorola, Inc. 1990 106