AdTech Ceramics

Company Overview Advanced Technical Ceramics Company (AdTech Ceramics) is located in Chattanooga, Tennessee. ● Founded with a proven employee base and manufacturing capability for multilayer co-fired electronic packages ● Processes revolve around 30 plus years of experience in material science, engineering, design, tooling and manufacturing of multilayer ceramics ● Materials include Alumina (HTCC), Aluminum Nitride, BeO and LTCC ● Chemical Milling services available (step lids, leads, seal rings) in Kovar, Alloy 42, Spring Steel and Stainless Steel ● Market emphasis targets engineering solutions for high reliability applications ● Business model focuses on long term stability and growth ● Manufacturing capabilities include prototype to high volume production ● US owned, US based, ITAR Compliant ● MIL-1-45208 ● ISO 9001:2008 Certified. AdTech Ceramics continues to drive process, facility and equipment improvements and advancements, and actively seeks new opportunities in advanced Note: These general guidelines should be used for typical designs. If exceptions or special requirements are needed they should be reviewed with AdTech Ceramics. Process OverviewElectronic packages produced with the co-fire multilayer ceramic process have four distinct processing stages: ● Materials Preparation ● Green Processing ● Sintering ● Post-fire Processing Materials Preparation Ceramic materials are prepared by milling precise amounts of raw materials into a homogeneous slurry. This mixture is principally ceramic powders of controlled particle sizes with fluxes and small amounts of organic binders and solvents. This slurry is poured onto a carrier and then passed under a blade to produce a uniform strip of specific thickness. When dried, this strip becomes a ceramic-filled “tape” which is easily handled in rolls or sheets for unfired processing. Metal powders of exact compositions and particle sizes are prepared as “pastes” for subsequent screen printing on the green ceramic tape, or in some cases, on the fired ceramic. Likewise, ceramic powders can be prepared as pastes to be used as screen printed dielectric layers. Green Processing Except for very large or complex products, individual products are arranged in arrays for multiple processing. Via holes, edge castellations and cavities are then punched in the tape. Because of the abrasive nature of ceramics, special tooling must be used for these operations. Green processing of ceramic is very sensitive to particulates and is done in a Class 10,000 Clean Room. Via holes are filled with a refractory metal paste, or bore coated, to become the vertical electrical interconnections between the layers. Conductive circuit patterns are printed onto the ceramic tape with refractory metal pastes using precision screen printing. The layers are then stacked and laminated together. At this point the array may be scored to allow post fire operations in the array, or individual products may be cut or punched out of the array prior to sintering.Sintering (Firing) The ceramic-refractory metal composite structure is sintered, or “co-fired,” at temperatures as high as 1600C in a carefully controlled atmosphere. During the firing process most ceramics shrink approximately 20% in the X, Y and Z dimension. Hot pressed AlN is physically constrained in the X and Y dimensions so that all shrinkage occurs in the Z dimension. Post Fire Processing Ceramic packages are typically supplied with Gold over Nickel plating on the metallized areas, and can have metal components attached by brazing. Nickel is plated on all exposed metal surfaces to allow brazing and to provide solderability. Metal leads, pins, seal rings and heat sinks are attached by brazing with silver or a silver-copper eutectic alloy to form a strong hermetic joint. Final plating may be either electroless or electrolytic gold. Electrolytic plating requires that all exposed circuits be temporarily electrically connected through a lead frame, internal tie bar, or a combination of the two. A combination of electrolytic and electroless plating can be used if designs require. (Note: in this case metal components must be electrolytic.) Post fire metallizations can be used for applications requiring special flatness or precision tolerances. Ceramic grinding, lapping and ultrasonic machining are available for applications requiring features not achievable as-fired. Vertical InterconnectsThe basic interconnect between layers is the metal-filled via. Also used are bore coated (metallized side wall) vias, metallized edge castellations and flat edge metallization. Generally, via diameters should be at least the thickness of the ceramic layer and via pitch 2.5 times the layer thickness. Vias may require a cover pad to be printed with the metal interconnect pattern to assure optimal electrical connection between layers. Horizontal InterconnectsCircuit layout is usually a compromise between maximizing conductor trace width to minimize resistance, and maximizing the space between conductors, and other metal features such as vias, in order to minimize yield losses. It is desirable to pull back buried metal features from the ceramic edge, and neck down conductors that terminate with edge metallization. Internal ground planes should be limited to a maximum of 75% metal coverage.Special Feature Design GuidelinesSpecial consideration should be given to the design of the following features: ● Cavities ● Wire Bond Pads ● Metal Components ● Special Enhancements or Finishes CavitiesCavities are punched into the ceramic in its green state. Metallization should generally be pulled back from the edges of cavities. When cavity floors are metallized, the metallization should extend beyond the cavity wall to assure complete coverage. Wire Bond Pad DesignBy designing wire bond pads in a radial pattern (from the center of the cavity) it is possible to compensate for variations in the co-fired shrinkage. For very high density applications wire bond pads can be staggered in a double row around the die, achieving pads as small as 0.15mm (.006") x 0.15mm (.006") on an effective 0.15mm (.006" )pitch.Screened DielectricScreen printed dielectrics are frequently used to reduce overall ceramic thickness, cover exposed circuitry, or form solder or braze dams. The composition of the screened dielectric is the same as that of the base ceramic and is generally applied in the green state for sintering during the co-fire process.Metal ComponentsMetal components such as seal rings, heat sinks and lead frames may be attached to metallized patterns on the ceramic by high temperature brazing. Leads may be necked down or formed in the braze pad area. Attachment of metal components to aluminum nitride packages is considered custom and developmental due to TCE mismatch between brazed metal alloys and the AlN. HTCC Thermal EnhancementsThe thermal performance of co-fired alumina packages may be improved by adding thermal vias, or replacing the ceramic base with a brazed heat-sink such as Molybdenum (Mo), Copper Tungsten (Cu-W), Copper Molybdenum (Cu-Mo) or Beryllium Oxide (BeO). Mechanical EnhancementsThe mechanical characteristics of a package may be enhanced through a number of procedures. Lapping, a precision grinding process, can be used to improve flatness or surface finish. Diamond sawing, grinding and ultrasonic machining are available to achieve special features or tighter tolerances. Laser disconnect can be used to allow for all electrolytic plating. AIN and BeO SolutionsMulti-layer AlN and metallized BeO substrates are also used for elegant thermal solutions for high power applications. BeO ceramics can be metallized and integrated into HTCC package designs, while AlN offers the multi layer circuit integration benefits of HTCC along with the thermal performance of BeO. Design CapabilitiesAdTech maintains in-house design capabilities, as well as excellent relationships with outside design service firms for overflow and special design needs. Additionally, AdTechs design staff can interface with and accept customer design data in a number of formats. Capabilities include but are not limited to: Engineering Software: ● AutoCAD ● Solid Works ● CAM 350 Customer Interface - CAD Data Types: ● AutoCAD.DXF or .DWG ● Gerber Plot Data (RS274, RS274X) ● MDA Plot Data ● Barco PDF AdTech Ceramics can accept customer files via internet e-mail at design@AdTechCeramics.com or FTP upload.pecial CapabilitiesAdTech prides itself on being the innovation leader in the ceramic package business. Co-fired ceramic technology was invented in our Chattanooga facility over 35 years ago, and numerous patents have been issued over the years. Today, the company remains the leading US-owned non-captive supplier of ceramic electronic packages, and continues to lead the industry. Feed ThroughsAdTechs patented “split-via” concept provides an exceptionally reliable method of edge metallization without concern for processing damage at the point where metallization wraps around the edges. Ceramic PedestalsA Ceramic pedestal may be used in the package design to allow for self-jigging of metal or ceramic Seal-Ring. Circuitry can be added to a pedestal that connects to package base. Microwave Design AssistanceAdTech Ceramics produces HTCC and AlN packages for microwave applications in the X through K band frequency ranges. It has a design process that uses state of the art 3D Finite Element Method (FEM) simulators and proprietary numerical simulators. Electromagnetic Simulation This process can yield market-differentiating performance while maintaining cost effective solutions. The alternative is to resort to the old cycle of fab, test and redesign. The AdTech solution, on the other hand, offers world class performance with cost competitive ceramic packaging solutions. Thermal Modeling AdTech Ceramics is able to analyze and improve the thermal performance of the ceramic package. It does so by using its unique combination of proprietary thermal analysis tools, commercially available thermal analysis software and highly qualified engineering staff. This capability improves performance and reduces cycle time.Refractory Metal Standoffs For the ultimate in standoffs, AdTech can co-fire refractory metal "bumps" on BGAs or substrates that will retain their shape through multiple solder reflow operations. A Ceramic pedestal may be used in the package design to allow for self-jigging of metal or ceramic Seal-Ring. Circuitry can be added to a pedestal that connects to package base.Chemical MillingIn addition to ceramic products, AdTech makes and supplies high quality chemically milled products in Kovar, Alloy 42, Stainless and Spring Steel. Products include step lids, lead frames, seal rings and other applications. Products can be supplied as etched, or with Ni/Au plating for seam welding applications.Materials SelectionMultilayer ceramic electronic packages can be produced with a wide choice of materials, each designed to meet specific application needs. The choices include: ● Ceramics ● Metallizations ● Brazed Components ● Platings Ceramic Materials AdTech offers a choice of ceramic materials: ● Alumina (HTCC) ● Aluminum Nitride (AlN) ● Low Temp Co-fired Ceramic (LTCC) ● Beryllium Oxide (BeO) Additionally, custom materials can be developed to meet special needs.Alumina (92% Al2O3) - HTCC Alumina is the most popular ceramic material for multilayer packages. Because it has been used for many years its performance is well characterized, and it has a proven track record. Alumina offers high strength, good thermal conductivity, hermeticity, excellent electrical properties and the lowest cost high density interconnect. HTCC is available in both white and black. Aluminum Nitride (AlN)Due to its high thermal conductivity and excellent Thermal Coefficient of Expansion match to Silicon, Aluminum Nitride is the ceramic material of choice for high heat dissipation and/or large chip applications. AdTech Aluminum Nitride is produced using hot press technology. It is ideal for applications requiring very high thermal conductivity (160 W/mK). The patented hot press process allows precision tolerances (0.15%). Aluminum Nitrides primary application is for MCMs requiring multiple internal metal patterns (30+ layers possible) with vias only terminating on the top and bottom surfaces. The external metal patterns are applied to a precision surface finish, flat to within .001"/inch, using thin film processingMetalization Metallizations are largely dictated by the ceramic base material. Alumina and Aluminum Nitride require refractory metals such as Tungsten (W) and Molybdenum (Mo) for high temperature sintering in protective atmospheres. Brazed Components Kovar and Alloy 42 are the most popular metals for brazed components due to their good thermal coefficient of expansion match to ceramics and relatively low cost. However, other materials such as Molybdenum and Copper Tungsten, can be successfully brazed to metallized ceramic for heat sink applications. Plating AdTech offers electrolytic and electroless Nickel in thicknesses typically from 50" to 300" and electrolytic and electroless Gold in thicknesses typically from 30" to 100". Thicknesses outside these ranges are also possible. A combination of both plating types can be used if required.Mission StatementAdvanced Technical Ceramics Company strives for continuous improvement in quality and service to meet our customers requirements for high-performance ceramic packaging products. AdTech Ceramics growth is driven by sound business ethics, customer satisfaction and the continuous development of new applications requiring advanced technical ceramic solutions.Quality Policy AdTech Ceramics is dedicated to achieving superior levels of customer satisfaction through teamwork and continuous improvement. We will provide quality to our customers, both internal and external, and will deliver products and services which will meet or exceed customer expectations in accordance with our Quality Management SystemPlease visit our full design page