SE-20, MC Series Lid Attach
Solder Lid Attachment Procedure
The lids supplied with the SE20 and MC Series semiconductor packages are nickel and gold plated Kovar™ with an attached AuSn (gold-tin) eutectic attach preform. The recommended method of attachment is by solder flow. The profile should provide a peak of 300°C - 315°C. The peak should remain above 280°C for 1 - 2 minutes with a preheat cycle time of 3 - 4 minutes. The type of atmosphere used should be either reducing (forming gas) or protective (nitrogen). StratEdge uses two-pound clamps to position the lid. A process should be developed and optimized with the specific equipment at your facility. Results will vary according to:
1. The type of furnace employed: a) Amount of heated length, b) Belt speed, c) Stability of atmospheric flows within, and d) Other physical characteristics such as belt width.
2. The size and mass of the assembled part and fixturing (used to keep the lid aligned) in combination. More overall mass requires more heat.
3. The clamping force or amount of weight used. The weight must be sufficient to insure proper bonding, but not so great as to force the solder out of the joint. This can be accomplished with weights, spring clips, or other types of clamps. Two-pound spring clips (per package) have been found to provide satisfactory results.
Cleaning of lids with solder preforms is not recommended.
If components need to be removed from the package, the package should not be heated above 300°C.
Please feel free to contact the factory for further assistance.