Pinsheng Electronics Co.,Ltd
Definition of PCB high frequency board
Circuit board factory, high frequency board refers to the special electromagnetic frequency circuit boards, used for high frequency (greater than 300 MHZ frequency or wavelength is less than 1 meter) and microwave (greater than 3 GHZ frequency or wavelength is less than 0.1 meters) in the field of PCB, is on the microwave base copper clad using common rigid circuit board manufacturing method of a part of the process or the use of special processing methods and the production of circuit boards.
Generally speaking, high frequency board can be defined as circuit board with frequency above 1GHz.
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With the rapid development of science and technology, more and more equipment designs are applied in the microwave frequency band (> 1GHZ) or even above the millimeter wave field (30GHZ), which also means the frequency is higher and higher, and the requirement on the substrate of the circuit board is higher and higher.
For example, the substrate material needs to have excellent electrical performance and good chemical stability. With the increase of power signal frequency, the loss requirement on the substrate is very small, so the importance of high frequency plate is highlighted.
PCB high frequency board application area
Mobile communications products;
Power amplifier, low noise amplifier, etc.
Passive devices such as power dividers, couplers, diplexers and filters;
In the fields of automobile collision avoidance system, satellite system and radio system, the high frequency of electronic equipment is the development trend.
Classification of high frequency plates
Powder ceramics are filled with thermosetting materials
The Taconic company's TLG series
B. processing method:
Similar to the epoxy/glass woven fabric (FR4) process, only the plates are brittle and easy to break, and the life of the drill heads and gongs is reduced by 20% when drilling and gongs.
Rogers RO3000 series, RT series, TMM series
Arlon's AD/AR, IsoClad, CuClad
Taconic inc. 's RF series, TLX series, TLY series
Taixing microwave F4B, F4BM, F4BK, tp-2
B. processing method:
1. Material opening: the protective film shall be retained to prevent scratches and indentation
2. The drilling
1. Use the new drill nozzle (standard 130), one by one is the best, and the pressure of the presser foot is 40psi
2. The aluminum sheet is the cover plate, and then the PTFE plate is tightened with 1mm melamine pad
3. After drilling, blow out the dust in the hole with the air gun
4. With the most stable drilling rig, the drilling parameters (basically, the smaller the hole, the faster the drilling speed, the smaller the Chip load, and the smaller the recovery speed)
3. The hole processing
Plasma treatment or sodium naphthalene activation is beneficial for hole metallization
4. PTH sink copper
1 after microetching (the microetching rate is controlled by 20 micro inches), the PTH is pulled from the oil removal cylinder to enter the plate
2 if necessary, pass the second PTH.
5. The resistance welding
1 pre-treatment: acid wash board, not mechanical grinding board
2 after the pretreatment for board (90 ℃, 30 min), brush green oil curing
Three points three classes of board: a 80 ℃, 100 ℃, 150 ℃, each time 30 min (if you have found the substrate surface to jilt oil, can rework: wash the green oil, activation treatment again)
The gong plate 6.
Place the white paper on the line surface of the PTFE board and clamp the fr-4 substrate or phenolic substrate with a thickness of 1.0mm etching copper.
High frequency gong board lamination method
The rough edges of the rear boards of gongs need to be carefully repaired by hand to prevent damage to the base material and the copper surface, and then separated by a considerable size of sulfur free paper, and visual detection, to reduce burrs, the key is that the gongs have a good removal effect during the process.
The process flow
NPTH PTFE plate processing process
Blanking - drilling - dry film - inspection - etching - corrosion - soldering - character - spray tin - molding - testing - final inspection - packaging - shipment
PTH of PTFE plate processing process
Cutting - drilling - drilling - hole processing (plasma treatment or sodium naphthalene activation)- sinking copper - plate electrical - dry film - inspection - chart electrical - etching - erosion - soldering - character - soldering - molding - testing - final inspection - packaging - shipment
Difficulty in high frequency plate machining
1. Copper sinking: the hole wall is not easy to be copper
2. Picture rotation, etching, line width gap and sand hole control
3. Green oil process: control of green oil adhesion and bubbling
4. Strictly control board surface scratches and so on in each process.
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