HICs in Semiconductor Packaging
For semiconductor packaging, HICs are packed inside a moisture-sensitive bag, along with the desiccant, to aid in determining the level of moisture to which the moisture-sensitive devices have been subjected. Moisture sensitivity levels are indicated with a number as in the MSL list.
JEDEC is the leading developer of standards for the solid-state industry and sets the standards for semiconductor packaging. The latest JEDEC standard, the Joint Industry Standard for the “Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices” J-STD-033B, sets forth the use and testing of humidity indicator cards in the dry packaging of semiconductors. HICs are used to ensure that the humidity within dry packed barrier bags remains at safe levels for surface mount devices. In the past, HICs for the semiconductor industry have indicated relative humidity (RH) levels of 5, 10 and 15 percent. However, JEDEC and IPC released JSTD-033B in 2005, which requires the use of an HIC that indicates RH levels of 5, 10 and 60 percent.
The standard includes the use and testing of humidity indicator (HI) cards in the dry packaging of semiconductors. The methods outlined in the standard are prescribed by JEDEC and IPC to avoid damage—like cracks and delamination—from moisture absorption and exposure to solder reflow temperatures that can result in yield and reliability degradation.
The stipulations of J-STD-003B state:
1) HICs must adhere to a standard, minimum color-change quality level to ensure accuracy and readability between dry and humid states: The Color Meter Test Method, quantitatively determines the accuracy of color change HICs. The levels, as outlined in the J-STD-033B revision, require a “significant, perceptible change in color” between noted humidity levels. Manufacturers are required to test their cards for accuracy using a colorimeter device and be required to provide a test report to the customer certifying that the HIC meets quality requirements.
2) HICs must indicate humidity levels for MSL 2 Parts, in addition to MSL 2a to 5a: Whereas previous cards used a 5, 10 and 15 percent relative humidity spot system to indicate humidity exposure levels for moisture sensitive components, the new HIC will now feature spots indicating 5, 10 and 60 percent. The change means that cards will now indicate humidity exposure for Level 2 MSL devices. Additionally, a positive reading on the 60 percent spot indicates that cards should not be re-used, as the high levels of humidity to which the card has been exposed will jeopardize the accuracy of low (5% RH) readings. The 5, 10, 60 percent cards are complaint with European Community Council Directive 67/548/EEC as long as they do not contain more than the applicable amount of cobalt chloride.
The full standard can be downloaded from JEDEC.
Read more about this topic: Humidity Indicator Card