materials are commonly used in high density interconnect pcbs
High Density Interconnect PCBs are used to make industrial control panels and automation systems. They are designed for ruggedness and durability. They are employed in avionics and military equipment and are also found in industrial settings including manufacturing, warehousing and transportation. They provide a reliable platform for collecting and transmitting data to optimize operations.
There are many advanced technologies enabling high density interconnect pcb, such as laser drilling and imaging of fine features, thinner dielectric materials, and sequential lamination. These techniques increase the layer count and allow for smaller vias, which reduces routing time and cost. However, it is the selection of the right materials that is critical to a successful design.
The first step in selecting a suitable material is to determine the operating frequency and allowable signal loss. Then, select a material that has the thermal, electrical and chemical properties required by the application. There are a wide variety of substrate materials to choose from, including FR-4 and several different epoxy resins with specific classifications, products, and brand names.
What materials are commonly used in high density interconnect pcbs?
For example, Teijin’s Nexus and Panasonic’s Megtron 6 are high-performance laminates that offer low dielectric thicknesses of only 25 microns. This allows for tighter lines and spaces and prevents signal integrity problems. The choice of the right laminate also depends on the glass transition temperature (Tg) of the material. It should be higher than the maximum withstanding temperature. Otherwise, the material could liquefy under the bare copper surface, and the circuit would not function.
A key feature of HDI PCBs is the use of microvias, which are small conductive holes that connect layers in an HDI multi-layer board. These tiny holes are drilled and plated prior to the lamination of outer layers. They can be plated with either nickel or gold.
The use of microvias in the PCB eliminates stubs that radiate signals and cause noise. It also increases the number of possible routing paths and decreases inductance in the circuit. High-density interconnect PCBs are rapidly growing in popularity due to their ability to accommodate more complicated circuitry within a smaller space than traditional circuit boards.
They also allow for more efficient use of the board’s space, resulting in less clutter and improved signal integrity. In addition, HDI circuit boards often feature smaller vias and capture pads alongside higher connection pad densities, which makes them ideal for telecommunication equipment such as cell phones and laptops.
To avoid signal attenuation and cross-talk, it is important to use a high quality laminate with a good dielectric constant (Dk) and dissipation factor (Df). A higher Df may help to reduce the effects of signal reflection and radiation, but the best option for a high speed digital application is a material with a flat Dk-frequency response. For instance, a low-loss PTFE (polytetrafluoroethylene) such as Isola Tachyon 100G can perform well up to 20 Ghz.