What are the baking methods for semiconductor devices? How long will it take?

Date：2022-08-17 18:22:27 Views：2775

After the PCB is manufactured, there is a shelf life. Beyond this shelf life, the PCB needs to be baked. Otherwise, it is easy to cause the PCB to explode when the PCB is produced on SMT. The baking board can remove the moisture on the PCB circuit board and electronic components. After the PCB circuit board reaches a certain temperature, the flux can better combine with the components and pads, and the welding effect will be greatly improved. The storage time of PCB and the temperature and time of baking PCB are regulated by the industry. Details are as follows:

1、 PCB control specification

1. PCB unpacking and storage

(1) If the seal is not opened and the manufacturing date is within 2 months, it can be directly put into use

(2) The manufacturing date is within 2 months, and the unpacking date must be marked after unpacking

(3) The manufacturing date is within 2 months, and the product must be put into use within 5 days after unpacking

2. PCB baking

(1) Bake at 120 ± 5 ℃ for 1 hour if the sealing and unsealing are more than 5 days within 2 months of the manufacturing date

(2) 2 months after the manufacturing date, bake at 120 ± 5 ℃ for 1 hour before going online

(3) 2 to 6 months after the manufacturing date, bake at 120 ± 5 ℃ for 2 hours before going online

(4) 6 to 12 months after the manufacturing date, bake at 120 ± 5 ℃ for 4 hours before putting into production

(5) The baked PCB must be used within 5 days (put into IR reflow), and the unused PCB needs to be baked for another hour before it can be used online.

(6) 1 year after the manufacturing date, bake it at 120 ± 5 ℃ for 4 hours before putting it on line, and then send it to the PCB Factory to spray tin again before putting it on line

3. PCB baking method

(1) Large PCBs (above 16 ports and including 16 ports) are placed horizontally, with a maximum number of 30 pieces in a stack. Open the oven and take out the PCB within 10 minutes after baking, and place it horizontally for natural cooling (it needs to press and protect the plate Bay fixture)

(2) Small and medium-sized PCBs (including 8Port or less) are placed horizontally. The maximum number of stacked PCBs is 40. The number of upright PCBs is unlimited. Open the oven and take out the PCB within 10 minutes after baking. Place it horizontally and cool it naturally (it needs to press and protect the plate Bay fixture)

2、 Preservation and baking of PCB in different regions

The specific storage time and baking temperature of PCB are not only related to the manufacturing capacity and manufacturing process of the PCB manufacturer, but also related to the region.

The shelf life of PCB made by OSP process and pure gold deposition process is 6 months after packaging. Generally, baking is not recommended for OSP process.

The storage and baking time of PCB have a great relationship with the region. The humidity in the south is relatively heavy, especially in Guangdong and Guangxi. In March and April of each year, there will be "back to the South" weather, with continuous rain and very humid. PCB exposed to air must be used up within 24 hours, otherwise it is easy to oxidize. After normal opening, it is best to use up within 8 hours. For some PCBs that need to be baked, the baking time is longer. In the north, the weather is generally dry, and the storage time of PCB is longer, and the baking time can also be shorter. The baking temperature is generally 120 ± 5 ℃, and the baking time is determined according to the specific situation.

The storage time, baking time and temperature of PCB cannot be memorized by rote. Instead, specific problems should be analyzed and specific choices should be made according to the manufacturing capacity, process, region and season of different manufacturers on the basis of PCB control specifications.

3、 Baking requirements

1. Regularly check whether the material storage environment is within the specified range.

2. The personnel on duty must be trained.

3. If there is any abnormality in the baking process, relevant technical personnel must be informed in time.

4. Anti static and thermal insulation measures must be taken when contacting materials.

5. Lead containing materials and lead-free materials need to be stored and baked separately.

6. After baking, it must be cooled to room temperature before putting on-line or packaging.

4、 Precautions for processing and baking

1. Wear thermal insulation gloves when the skin contacts the PCB board.

2. The baking time must be strictly controlled and cannot be too long or too short.

3. The PCB after baking must be cooled to room temperature before it can be put on line.

The above is the related content of semiconductor device baking compiled by Chuangxin testing group. I hope it can help you. Our company has professional engineers and industry elite teams, and has three standardized laboratories with an area of more than 1800 square meters. It can undertake various test projects such as electronic component testing and verification, IC authenticity identification, product design and material selection, failure analysis, functional testing, factory incoming material inspection and tape weaving.