Laser Bonding Meets High Reliability Needs

Mundt & Associates, Inc. Introduces the New Model IB-1284 Laser Bonder

Laser bonding designs can improve your product performance, product yield, and overall product reliability.

The established industries that will benefit immediately from laser bonding technology include medical, aerospace, automotive, and semiconductor industries. Laser bonding is a step up in reliability over existing bonding technology.

Comparison Technologies

ULTRASONIC BONDING

Ultrasonic bonders have been around for years and engineers have been forced to design around their imperfections. There was no alternative offered until laser bonding was created. The following weaknesses of ultrasonic bonding have been amended with laser bonding:

• Laser bonding has reformed bond reliability by delivering a larger degree of security
• Bond forces are lower to minimize damage to fragile components with laser bonds
• Non-rigid or flexible pads can be fused more easily with laser bonds
• Vibration-sensitive units can easily be laser bonded
• A wider range of materials can be used with laser bonding
• With laser bonding, it is not necessary to heat the entire device

BOND RELIABILITY

Ultrasonic bonds depths are in the order of angstroms. With the IB-1284 laser bonder, the bonds are actually welds with controllable bond depths which range from sub-micron to mils, depending on what the process requires.

Figure 1 shows an SEM image of a bond with about 800 nm of weld penetration. The result of the controllable weld/bond depth is increased bond reliability.

Figure 2 shows the side-by-side results of cyclic tests done on ultrasonic wire bonds vs. laser bonds. The results show that laser bonds (LRB), in this test, have several orders of magnitude better cycle life than the comparable ultrasonic bond (wire).

BOND FORCE

The IB-1284 technology laser bond forces are very low. Enough force is only required to provide intimate contact between the ribbon or wire and the pad that it is being bonded to. These forces are substantially less than the force used with an ultrasonic bonder. The ribbon and wires are not sharply deformed and will not cause high stress points for adjoining breakage during interconnect flexing.

NON-RIGID BOND PADS

The IB-1284 laser process does not depend on vibration to make the bond, so bonds can be made to pads that are not rigid. The picture in figure 3 shows a hole drilled in a thin aluminum sheet, with a laser bonded and looped pin sitting loosely inside.

FRAGILE COMPONENTS

Fragile components cannot withstand the vibration produced during an ultrasonic bond. With the laser bond process there is no pulsation and bond forces are very low. This minimizes damage to very fragile elements, thus expanding the range of components and materials that can be bonded.