: GA-170-LL/ GA-170B-LL

Transcription

1 Grace Electron Corp. Processing Guide Phenolic Cured Material Laminate/ Prepreg : GA-170-LL/ GA-170B-LL Grace Electron Corp. Tech. & QA Dept. Revision 2010/6/14 Page 1 of Group

2 Grace Declaration: The processing conditions included in these guidelines were developed through in-house evaluation and field experience. To ensure optimum processing PCB fabricators are advised to evaluate and select conditions to suit actual circumstances. Part1 Prepreg storage 1.1 Prepreg storage suggestion: Prepreg panels packaged in vacuum sealed bags should be stored Condition A: 23, 50% RH for three months Condition B: lower than 5 for 6 months from date of manufacture. The storage environment should be free of any catalytic effect such as UV light or radiation. 1.2 Prepreg Handling: Prepreg requires control of storage conditions and lifetime Following receipt prepreg should be immediately moved to a temperature and humidity controlled environment for storage A FIFO (first in first out) inventory management system should be used Once packaging is opened exposure to the air may cause prepreg properties to degrade. Exposure to the air must be limited to 24hrs. Any prepreg not used within 24 hrs should be repacked in vacuum bags and desiccated before re-use Precautions must be taken to ensure that prepreg is kept clean and free from contamination. Part2 Laminate storage 2.1 Laminate storage suggestion: Laminate should be stored in an environment free from corrosive fumes Laminate which has been stored more than 12 months should be inspected for the effects of oxidization of the copper cladding. Revision 2010/6/14 Page 2 of Group

3 2.2 Laminate baking suggestion: In order to holding the dimensional stability of the laminate after shearing into panel sheets, the baking is recommendation. Materials GA-170-LL Temperature 170 Time 2~4 hrs Note: When the storage of laminate is over one year, the properties must be retested and re-certified to agree upon specifications. Part3 Inner layer processing 3.1 Inner layer copper treatment Both oxide and alternative oxide treatments may be used to enhance inner layer bond adhesion Following oxide/alternative oxide treatment inner layers must be baked to remove absorbed moisture. Baking temperature and time must be chosen in accordance with the chemistry suppliers recommendations Inner layers should be laminated within 12 hrs of oxide/alternative oxide treatment and baking As a general rule the inner layer treatment finish should be capable of achieving a peel strength of greater than 4lb/inch to be suitable for lead-free assembly. 3.2 Lamination conditions Heating rate suggestions when material temperature range is 90~130 Heating rate: 1.2~2.5 /min for 350~400psi pressure (24.1~27.6 Bar) Heating rate: 3.2~5.5 /min for 250~300psi pressure (17.2~20.7 Bar) Revision 2010/6/14 Page 3 of Group

4 3.2.2 Material should be maintained at for at least 70 min to fully cure the phenolic epoxy resin In order to avoid warp and twist the cooling rate should be kept under 1.5 /min until the temperature of the material is under 130. Note: These conditions are for reference. Actual conditions must be chosen according to board design and equipment as well as other factors. The PCB fabricator is also advised to confirm by test that actual product performance is achieved under the chosen process conditions. Part4 Drilling process 4.1 Dilling parameters for filled Phenolic cured epoxy must be evaluated to suit the particular design. Factors such as layer count, thickness, inner layer copper will influence actual drilling conditions. 4.2 The parameters listed are a reference for customer trials. Diameter (mm) Speed (KRPM) Infeed (IPM) Chipload (µm/rev) Max. Hit Ø < ~95 50~60 13~18 500~ < Ø <1.0 80~98 75~85 22~ ~2000 Ø >1.0 25~48 54~85 45~ ~ Baking condition after drilling: In order to ensure the hole reliability of high layer PCB and BGA area, Grace recommends to baking the laminates just after drilling to releasing residual stress in the laminates. Materials GA-170-LL Temperature 170 Time 2~3 hrs Note: In baking process, all laminate panel sheets should be kept cleaning. Revision 2010/6/14 Page 4 of Group

5 Part5 Desmear and weight loss For process control purposes weight loss should be controlled within the range mg/dm 2, The PTH back light should be over 8 grades. Part6 Routing 6.1 Routing parameters for filled Phenolic cured epoxy must be evaluated to suit the particular design. Factors such as layer count, thickness, inner layer copper will influence actual routing conditions. 6.2 The parameters listed are a reference for customer trials. Diameter (mm) Speed (KRPM) Infeed (IPM) <1.0 45~50 20~ Ø <1.4 40~45 20~ Ø <2.0 25~40 20~ Ø <2.6 20~27 30~ Ø 15~18 30~60 Part7 Finished PCBs 7.1 Unprotected PCBs absorb moisture from the environment. Generally accepted best practice is that this absorbed moisture must be removed by baking prior to soldering, SMT reflow or similar high temperature processes. 7.2 To avoid degrading the solderable finish actual baking temperatures must be chosen to suit the particular solderable finish of the PCB. Consult with the supplier of the solderable finish to obtain the recommended temperature and time for baking. 7.3 HASL PCBs should be baked at 125 for 2-4hrs prior to assembly depending on the level of humidity and the assembly process temperature. Revision 2010/6/14 Page 5 of Group

6 Part8 Packaging of PCBs Vacuum packaging can be used to limit moisture pickup and may be appropriate for PCBs which are subject to long term storage. Prior to packaging good practice demands that PCBs are baked to remove moisture. Packaging should be agreed between the user and supplier to meet the actual requirements. Materials GA-170-LL Baked Temperature 125 Time 3~6 hrs PCB S moisture absorption may increase risk of delamination during assembly processing, the PCB fabricator is advised to determine the Maximun Moisture Content (MMC) of the product immediately prior to PCB packaging, the in-house evaluation result of the relationship between PCB reliability and MMC for reference: Note: All values mentioned above are just for reference, the curve maybe modified depend upon board design, as well as other factors. Revision 2010/6/14 Page 6 of Group