HOME ] UP ] FEEDBACK ] CONTENTS ] SEARCH ]
Tip Diameter

Capillary Design ] [ Tip Diameter ] Face Angle ] OR Dimen. ] Tip Finish ] Hole Diameter ] Core Angle ] ICA 1 ] ICA 2 ] CD ] Fine Pitch 1 ] Fine Pitch 2 ] Problem ] Order ] Order 2 ] Tip Modification ] Side Reliefs ] Important 1 ] Important 2 ]
SITE LINKS

 

 

GAISER TOOL COMPANY

Gaiser Tool Company - Home Page

PREVIOUS PAGE

NEXT PAGE

GAISER CAPILLARY INFORMATION

3. TIP DIAMETER

GTC Figure 2

Figure 2. Besides two capillaries, one with a tip diameter (T dimension) of 0.0090in./229m; the other T dimension is 0.0065in./165m. The larger T dimension provides a longer bond length for a successful second bond; however the larger T dimensions limits access into fine-pitch applications.

 

GTC Figure 3

Figure 3. Picture to the right shows an example of a weak/chopped-off second bond. The primary reasons for weak/chopped-off bonds are: 

bullet

Capillary T dimension is too small

bullet Worn inside chamfer which shortens bond length of capillary

GTC Figure 4

Figure 4. The stitch bond on the left is made with a capillary having the T=0.0059in./150m. The middle stitch bond is made with a  T=0.0065in./165m. The stitch bond on the right is made with a T=0.009in./229m. A larger T dimension provides a longer bond length and therefore a larger surface area for a superior intermetallic weld. 

 

GTC Figure 5

Figure 5. A tool with the same capillary tip may provide stitch bonds with different widths. A stitch bond made in the East-to-West direction will be wider than a stitch bond made in the North-South direction. This is due to the ultrasonic motion of the capillary scrubbing across the wire. A stitch bond made in the North-to-South direction will be because the ultrasonic motion scrubs in-line with the wire.
Many of the newer wire-bonding machines are capable of counteracting some of the effect of the direction of the ultrasonic's by stage motion and other techniques. The goal of these innovations is to minimize the difference in stitch-bond strengths. To date, the scrub direction issue has not been completely resolved.

GTC Figure 6

Figure 6. There are several reasons for second bond nonsticking. Some of these are:

bullet Poor plating or metallization
bullet Contamination
bullet Lead or package not clamped rigidly, allowing the lead to move during scrubbing
bullet Lead surface not planar to the capillary's face
bullet Improper power, force or time settings
bullet Small T dimension

Get the BASIC CAPILLARY BONDING and DESIGN document in BASIC CAPILLARY BONDING/ DESIGN format

PREVIOUS PAGE

NEXT PAGE

HOME ] UP ]
Send mail to info@bita.se with questions or comments about this web site.
Copyright 1998 BITA ELEKTRONIK SVENSKA AB 
Last modified: 2016-08-22