Authored By:
Galen Alexander
Vi TECHNOLOGY, INC., San Jose, CA, USA
Cathy Combet and Ming-Ming Chang
Vi TECHNOLOGY, St. Egrève, France
Summary
Since its infancy the SMT industry has been driving toward the use of smaller and smaller components. Each resulting reduction in size leads to new challenges.
The latest development in this saga of miniaturization is, of course, the 01005 package. Progressively smaller and more portable electric devices have now pushed these components from the test lab into active mass production. With 01005 packages, every stage of surface mount assembly is faced with obstacles: from board design to component placement to paste reflow. All of these processes can introduce specific types of defects which are considered virtually impossible to rework due to the small size of the device. AOI has become an essential tool to ensure a superior yield in the assembly of 01005s.
This paper discusses the unique hurdles associated with each of the various processes. It also introduces new tools which are available now to overcome those hurdles and assist in the successful manufacture of devices using these components. These tools address the potential problems from multiple points in the production line: the paste print, component placement, and inspection review processes. Details will be presented about developments that provide recognition of tilted components via the selective implementation of 3D technology, more precise determination of component position by utilizing super-resolution algorithms, and that give quality control personnel the means to better assess the attributes of the resulting product with higher quality reference images.
Conclusions
The use of 01005 components in the production environment is steadily increasing. All aspects of the assembly process must be optimized in order to achieve good results for these tiny packages: from board design, to component placement, through the reflow process.
AOI systems are also challenged by the use of 01005s, but the technology is equipped to deal with these challenges and fully capable of providing the customer with accurate component locations and reliable defect detection.As manual inspection and rework are not practical choices, AOI is no longer an option in 01005 SMT lines; it becomes absolutely essential. The ideal scenario is to implement AOI at or following each of the critical stages of the SMT line: post-print and pre-reflow as process control tools and post-reflow for quality assurance.
In order to provide value to the user, an AOI system must be of the highest capability and equipped with powerful solutions to achieve the required resolution accuracy and inspection throughput, as well as having the capability to return reliable and relevant data to control and improve the 01005 process.
Innovative solutions must be considered and applied to overcome the existing limitations of automated inspection. Integrating select elements of 3D technology into a 2D system provides additional value and capability without breaking the bank or imposing unreasonable inspection times.
While new hardware such as image sensors with more pixels, faster cameras, CPUs, and frame-grabbers will continue to be developed and incorporated, maximizing current hardware is vital to meeting today's industry needs at a price the customer is willing to accept. Software solutions like super-resolution and subpixel analysis are cost-effective, yet provide the means to ensure that the demands of the strict 01005 process window are being met.
Initially Published in the SMTA Proceedings
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