An alumina PCB uses an electrically insulating aluminum-oxide ceramic as the circuit substrate. Choosing one begins with two separate decisions: which alumina grade meets the electrical, thermal and mechanical requirements, and which metallization process creates the required conductor pattern. “Alumina PCB” alone does not define either choice. This page is a starting point for an engineering specification and connects the existing grade and process resources on this site.
Alumina provides electrical insulation and conducts heat through the ceramic. Its thermal conductivity, dielectric properties, expansion and strength depend on the formulation and the conditions of measurement. Supplier property tables distinguish multiple alumina grades; do not apply one grade’s value to every alumina board. For material data used in a design calculation, identify the grade and obtain its current datasheet. See the original Kyocera material tables and CoorsTek alumina catalog as examples of grade-specific data, not as AluminaPCB product certificates.
The ceramic is only one layer of the heat path. Board-level performance also depends on ceramic thickness, conductor geometry, die attachment, interface material and cooling boundary. The thermal-conductivity guide separates material conductivity from the resistance of a finished substrate stack.
Purity labels are useful search terms but not complete procurement specifications. Compare the actual candidate grades at the required temperature and frequency, then review thickness, finish and process compatibility. A higher nominal purity does not automatically make a substrate the better choice for every circuit. Read the existing 96% alumina PCB overview and 99.6% alumina overview, then ask for the particular grade data behind any value you intend to use. The 96% versus 99.6% comparison is a decision aid; supplier data and the part drawing control the final selection.
Metallization determines conductor thickness, feature size, finish options and assembly compatibility. Thick-film printing, thin-film deposition, direct plated copper and direct bonded copper are different routes. The right choice depends on current, pad geometry, heat spreading, soldering or wire bonding, and the pattern’s critical dimensions. There is no universal trace-width or copper-thickness limit for all alumina boards. Start with the existing DBC versus DPC comparison and the thick-copper discussion. Confirm the particular ceramic, metal and process combination for the drawing before releasing it.
Alumina is worth considering when a circuit needs an insulating ceramic with a defined conductor pattern and a reviewed heat path. It is also brittle compared with an organic laminate, so edge handling, mounting loads and thermal expansion of adjoining materials matter. If the allowable temperature rise cannot be met with the available thickness and interfaces, compare another substrate material rather than assuming the ceramic alone solves the problem. The AlN versus alumina guide explains a common alternative, while the broader ceramic material overview introduces other families. Any cost or reliability conclusion must be checked against a real grade, stack, quantity and application.
For a fuller preparation guide, see the existing ceramic PCB design review page. Send your drawing or preliminary requirements to ask whether a specified alumina grade and circuit structure can be reviewed for quotation. Do not treat a generic value on this page as a confirmed fabrication limit.