August 8, 2012

Protecting Moisture-Sensitive Devices, Part II

In the last post on the Converge blog, we covered the IPC/JEDEC J-STD-020B standard definitions of moisture sensitivity levels (MSLs) and why protecting moisture-sensitive electronic devices is important. In this post, we will explain how Converge does that for our customers.

In our electronic component inspection process, Converge strictly adheres to the IPC/JEDEC J-STD-033B standard, which provides manufacturers and distributors with standardized methods for handling, packing, shipping and using moisture-sensitive devices (MSDs). This standard outlines procedures for avoiding moisture absorption that can result in delamination, cracking, or other types of damage when exposed to high temperatures. Component baking is an important part of those preventive measures.

When an order of MSDs arrives at Converge, our IDEA-ICE-3000-certified inspectors examine the shipping packages and components for any kind of discrepancy – including previous moisture damage. Ideally, MSDs should arrive in a vacuum-sealed bag along with desiccant to absorb traces of moisture and a humidity indicator card (HIC). An HIC features three vertical color spots that are sensitive to relative humidity values. The card changes color (typically from blue to pink) when the indicated relative humidity is exceeded. This tells inspectors that the parts need to be baked to “reset” their ambient room conditions exposure clock before they are shipped.

When indicated, Converge follows the baking procedures recommended by J-STD-033B. Our inspectors determine the length of baking time required for devices based on their MSL and package thickness. The parts are baked in our in-house calibrated ovens for the specified time and dry-packed immediately upon removal in a moisture-barrier antistatic bag, along with a new HIC and the appropriate amount of desiccant. In addition, Converge often bakes parts that arrive with blue (dry) HIC cards. Due to their heightened sensitivity, components rated at MSL 5 and 6 are baked regardless. Even MSL 3 and 4 parts with dry HIC cards will be baked if requested by the customer. And perhaps most important, every step is carefully documented for customer review.

No manufacturer can afford to take chances on parts that may or may not be completely dry. Does your distributor follow the IPC/JEDEC J-STD-033B standard? Be sure to ask before you get burned.