保存期限与烘烤条件.doc

Shelf-Life and Dry Baking Parameters.保存期限及烘烤条件Shelf-Life /保存期限Shelf-Life is a function of solderability. Solderability of any final finish degrades over time due to oxidation or intermetallic compound formation of different finishes. 設定保存期限有助于確保護焊性。任何形式表面處理會隨著過期而產生氧化或形成金屬複雜化合物，從而護焊性也會下降。Per IPC-4552 ENIG shall remain solderable for up to 6 months under controlled storage conditions. 依據IPC-4552化金板護焊性在受控條件下最多能維持6個月。Per IPC-4553 Im Ag shall remain solderable for up to 6 months under controlled storage conditions. 依據IPC-4553化銀板護焊性在受控條件下最多能維持6個月。Per the IPC the solderability of OSP shall be per the procurement documentation. OSP shelf life depends upon the OSP vendor and grade. For example Entek Cu-56 has a shelf life range of 3 to 6 months. Entek Plus-HT has a shelf life range of 6 to 12 months. 依據IPC規範OSP板護焊性要參考購買資料，不同廠商、型號的護焊劑壽命不一，如：Cu-56型號的松香能儲存3-6個月，Plus-HT型號的松香能儲存6-12個月。Per IPC-1601 Tin/Lead Hot Air Solder Leveling has an acceptable shelf life ranging from 6 months to a year. 依據IPC-1601噴錫板護焊性在壽命能維持6-12個月。Under controlled storage conditions the solderability shelf life may be extended to 12 months or more. To verify solderability of boards held in long term storage it is advisable to sacrifice one board from the manufactured lot in question for use as a solder sample. A solder sample processed through the assembly process verifies not only solderability of the final finish but compatibility with the overall assembly process as well. Solderability shall be in question on boards that are not stored properly.在受控條件下儲存期限可能會延長，為驗證長期儲存下的PCB板的焊錫性，建議從疑似批號中取出一片作為實驗樣品測試，這不僅能反映焊錫性，也能體現与組裝流程可適性，對於未儲存好的板子焊錫性是存疑的。Moisture absorption/吸濕性Printed circuit boards are hygroscopic. They shall absorb moisture to the point of equilibrium. Whereas boards readily absorb moisture they require help to force the moisture back out. IPC-1601 “Printed Board Handling and Storage Guidelines” specification section 3.4 and Table 3-1 provides guidance on the dry baking of printed circuit boards. PCB板具有吸濕性，鑒于此，有必要把這些濕氣赶出來，IPC-1601PCB板處理与儲存指南規範3.4中的表3-1提供了建議如下：Table 3-1 Recommendations for Printed Board Baking ProfilesPCB烘烤條件建議Final FinishTemperatureTimecomments Tin/化錫105 -125C4-6 hoursBaking may reduce solder ability.See 3.4.1.5烘烤過度會使焊錫性下降Silver/化銀105 125 C4-6 hoursSilver may tarnish. See 3.4.1.4烘烤過度會使銀面變暗Nickel/Gold/化金105 125 C4-6 hoursUsually no issue with extended bake on Nickel/Gold finish. See 3.4.1.2一般延時烘烤無大礙Organic Coating/松香See 3.4.1.1HASL/HAL/噴錫105 125 C4-6 hoursFinal surface thickness below 0.77m 30 in may turn into pure intermetallics and render the printe