PCB Manufacturing

Alumina PCB: Types, Advantages, Applications and Fabrication Process

Alumina PCB

What is Alumina PCB?

Alumina PCB or ceramic substrate PCB is a printed circuit board that uses aluminum nitride and aluminum oxide as its materials. Alumina oxide was the most used material in Alumina PCB. Alumina oxide has many features, like higher conductivity and a low thermal expansion coefficient. Also, alumina PCB boards provide effective thermal stability and enhanced PCB thermal performance. Almost 95% or more alumina materials are used in alumina substrates. So, due to the high purity of alumina, the boards have a smoother surface.

Commonly Used Alumina PCB Types

  1. 99.5 % Alumina Substrate: This type is mainly used for small-scale applications. So, we can get low conductivity and good strength. If we apply this type to PCB surfaces, then we can get a higher gain for boards. These substrates are available in different thicknesses and sizes.
  2. 99.6 % Alumina Substrate: This substrate is normally used in PCB industries due to its popularity. It has a high purity of alumina. So, we can easily get a smooth surface.
  3. 96% Alumina Substrate: This substrate is used for microelectronic PCBs due to its suitable construction. It is a hybrid solution for microelectronic PCBs. As we know, alumina PCBs provide higher heat conductivity and low CFT. So, this advantage is available on this substrate.

Alumina circuit board

Advantages of Alumina Printed Circuit Boards

Compared to other PCBs, alumina PCB has the following advantages:

  • High thermal conductivity
  • Great heat resistance
  • Excellent mechanical strength
  • Small in size
  • Strong durability
  • Low cost

 

Applications of Alumina PCB Boards

Alumina PCBs are widely used in lots of industries, especially the ones that need to be used in extremely high temperatures and need high thermal conductivities, here are a few of them. 

  • Lightweight Industries: As we know, alumina PCB boards are small in size with excellent features. So many companies make smaller circuits like lighting, sensors, etc., which would be beneficial for small industries due to their size and cost.
  • Aerospace Applications: Aerospace PCBs are controlled at higher temperatures in aerospace parts like engines, LED modules, etc., so Alumina PCBs are the best solution to operate PCBs at higher temperatures with excellent protection.
  • Automobile Industries: In automobiles, most sensors need protection and performance in an easy manner. So, with the help of the Alumina PCB, they can get protection and higher performance. After many experiments, some Alumina PCB manufacturers have realized that alumina PCBs are the most suitable and stable PCBs for the automobile industry.

The Manufacturing Process of Alumina PCB

Alumina PCB board

  1. Material Check and Cutting: Firstly, the material arrived at the production house from inventory. So, it has scratches and notches. After that, we need to cut alumina material according to our board thickness requirement.
  2. Drilling: In this stage, the PCB was fixed with fixtures for exact drilling. After that, the drilling program was loaded into the drilling machine, and that drilling machine drilled the holes according to the PCB drill layer.
  3. Image Transfer: Image transfer is one type of method to place circuitry images on copper using films. For image transfer scrubbing, dry film with protective film is required. Also, oxidation was not allowed on the surface. So please make sure the PCB is neat and clean. After scrubbing, circuitry film was applied to the PCB. Please make sure film registration is accurately placed; otherwise, it creates shorts and broken errors.
  4. Image Inspection: After image transfer, we need to check and inspect the image for proper registration. Mainly, this stage verifies short circuits, broken connections, and misalignment of the image. If the image transfer was not successful, then it needs more time to reconstruct them.
  5. PCB Etching: This stage removed unnecessary copper from the PCB. Once etching is done, circuitry images remain present on the PCB. Normally, etching was done by the chemical solvents.
  6. Solder Masking: A solder mask was applied to the copper layers. So, these solder mask openings were used for soldering at those locations only. Mostly, the alumina PCB board has a white solder mask color due to its use in lighting, etc. Also, we need to make sure Solder masking printing is done accurately; otherwise, it creates gang mask outfits, shorts, etc.
  7. Silkscreen Printing: After solder mask printing, silkscreen was applied to the PCB. It identifies the component reference designators, their polarity, part number, revision of boards, etc. We need some clearance from the mask for silkscreen printing.
  8. Surface Finish: Surface finish plays the most crucial role in the PCB manufacturing process. The surface finish was used for protection from oxidation and also as a proper soldering surface for the PCB and its components. There are many surface finishes available on the PCB market, like OSP, ENIG, HASL, gold body, etc.
  9. Routing and Scoring: After that, the routing and scoring program is loaded into the routing and scoring machine to depanelize or penalize the boards. Mostly, Alumina PCBs are the preferred routing methods for panelize or depanelize. But if some square boards come, then the score is most suitable to penalize them.
  10. Final Quality Inspection: After the whole manufacturing process is done, boards are returned to the final QA team to be inspected with different inspection methods like flying probe tests, high-precision tests, etc., so the PCB is created and anything that needs to be done can be done at this stage. The final QA team also confirms if additional requirements are needed, like a TDR report.
  11. Packaging: The shipping team attached the whole document of the PCB with the packaging of the boards. The shipping team packs the boards with depanelized or panelized boards according to the requirements. And also add markings and labels regarding PCB boards. And ship the boards to the particular address via FedEx and other delivery methods.

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