SMTA International Conference Proceedings


Authors: Jean-Marc Peallat and Mark J. Norris
Company: ViTechnology, LLC
Date Published: 9/22/2002   Conference: SMTA International

Abstract: With the introduction of the 0201, the SMD industry is facing a new challenge: "How do we control this process?" Inspecting 0201s generally means high-density boards with little or no room for ICT pads and impossible to inspect using Manual Vision Inspection (MVI).

From a process point of view, pads are smaller and the amount of solder paste is minimized, which means it is critical to have the right amount of solder paste in the right place. 0201 placement control is also very critical, because "the placement area" becomes very small: pads are 300 microns wide and tolerances are less than 100 microns. The combination of these two factors increases tombstone problems at the end of the line. So, AOI In-line control is the only solution to prevent defects and achieve the Zero Defect Line.

To control solder paste and component processes, the AOI system needs to be able to detect variations on very small values and be able to find trends in placement analysis. To achieve this goal, the AOI system has to be extremely accurate. Today, most of the placement machines are accurate to 60 - 75 microns. In order to be able to control placement accuracy, the AOI system should be 10 times better or between 5 and 6 microns.

Certain AOI companies understand the need for the Zero Defect Line and have developed the technology providing this AOI solution. The systems being brought to market today are required to have 5 micron accuracy. They also have the built-in SPC data collection tools and the capability to interface with the line management software supplied by either the Pick & Place manufacturers or third party software providers to "Close the Loop".

This article will help people to understand what the solution will be to future requirements for this state of the art process control. With 0201s, the challenge will not be only counting defects, but understanding your process with very high accuracy AOI measurement, the necessary trend analysis giving you the information you need, and the software communication tools working to close the loop achieving the Zero Defect Line.

Key words: 0201, inspection, accuracy, closed loop.

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