Mechanical Vibrations: Its Effect on Assembly Equipment and Methods of Characterization
As electronic packages keep shrinking in size,high-speed high-accuracy package assembly equipment are becoming more
sensitive to mechanical vibrations. Alignment,positional and pick & place accuracy can be compromised during high speed
operation due to sensitivity to mechanical vibrations which are generated within the assembly equipment,as well as from the
floor and neighboring machines. Vibrations can also affect process yield as a result of diminished accuracy. Semiconductor
package manufacturers are under constant pressure to increase output,at the same time are challenged by tighter alignment
accuracy requirements.
This paper describes the methodology used to characterize the vibration response of manufacturing equipment under
vibrating floor environment,and that of the manufacturing floor under vibration induced by operational equipment. Case
study of pick & place equipment shows significant differences in vibration levels were found in different building facilities
and factory floor conditions. Also described in the paper is reason why a standard/specification is needed for purchased
assembly equipment. Industry standard needs to be developed that can help specify how much vibration can be transmitted
from the machine to the floor,and how much internal and external vibration the machine should be able to withstand without
affecting performance or quality and reliability. Examples of possible solutions that manufacturers and equipment suppliers
can adopt to meet future needs for precision high-speed placement equipment are also discussed.