Precision polishing is a machining service invented by Accumet in the 1970s and we continue to perfect our skills and capabilities every day. Some of the many benefits of our ceramic and other substrate machining services is that we are ultra-efficient at polishing to the ideal thickness and uniformity you need, and we offer extremely smooth surface consistency from piece to piece. We understand that thickness and surface control of the substrate is important because circuit traces are designed for optimal impedance and control and uniformity of each trace has much to do with the substrate being a perfect carrier. Controlling the camber of the substrate to less than .0005'' allows the optimal transfer of photomask features, and this allows us to offer you the ability to achieve lines and spaces in the .0002” range. The surface finish as well as consistency from piece to piece also creates better yields and increased performance in higher frequency applications, as well as in infrared and visible/UV light applications.
The ceramic machining process for precision polishing is employed when a secondary step after lapping is needed to provide an even greater level of surface smoothness and evenness. (This is true for any substrate.) The surface finish tolerance limit for precision polishing is dependent upon the structure of the material used. This is why certain materials are best for specific applications, dependent on surface roughness of the raw, or as-fired material. For example, low-density 96% alumina can be lapped to 20 micro-inches and polished to less than 5 micro-inches, nominally. High-density 99.6% alumina can be lapped to 10 micro-inches and polished to less than 1 micro-inch, nominally.
When necessary, thickness tolerances with polished ceramic substrates can be brought down to ± .0005'' or even lower for demanding applications. Material defects, such as pits, can typically be lessened to a minimum diameter of 0.0125'' for 99.6% alumina and even lower for other materials. Accumet's micro-fine precision polishing process can further reduce a pit diameter down to 0.0'' for 99.6% alumina, and further for other material. Thickness tolerances as tight as .00005'' and surface finishes ranging from one tenth of a micro inch (.0000001”) to 5 micro-inches (.000005'') can be achieved, even at production rate volumes.
|Material||Surface Finish (u-inches)||Thickness Tolerance (Typ)||Applications|
|Polished 99.6% Alumina||Less than 1u-in||±0.0005"||Used for low to medium power RF & Microwave circuits|
|Polished 99.5% Beryllium Oxide (BeO)||Less than 4u-in||±0.0005"||Used for high-power DC/RF/Microwave circuits|
|Polished Aluminum Nitride||Less than 2u-in||±0.0005"||Used for high-power DC/RF/Microwave circuits|
|Polished Fused Silica||Less than 1u-in (60/40 optical)||±0.0005"||Used for high frequency circuits requiring extremely low loss of performance|
|Polished Sapphire||Less than 1u-in (60/40 optical)||±0.0005"||Used for optics, power electronic substrates & RF/microwave substrates|
We're located just north of Boston, Massachusetts in Westford, MA, and proudly service the entire US. We offer many laser services, ceramic polishing, machining, and secondary processing services, along with our lapping and precision polishing services.