What is IMS PCB? A Guide to Insulated Metal Substrate PCBs

IMS PCB

Introduction

With the miniaturization and performance demands of modern electronics, PCBs face growing thermal management challenges. As components become smaller and more densely packed, finding ways to dissipate heat is critical. This has driven the need for PCB solutions with better thermal conductivity to prevent overheating. One innovative solution that has emerged is insulated metal substrate (IMS) PCBs, also known as metal core PCBs or metal base PCBs.

IMS PCBs provide enhanced thermal performance by utilizing a metal layer as the core substrate. This metal foundation gives IMS boards an unmatched ability to conduct heat away from sensitive components. At the same time, the metal core provides a robust, rigid structure for thin PCB fabrication. IMS technology enables excellent heat dissipation, thermal management, and miniaturization not possible with standard PCB materials.

With advanced fabrication techniques, the metal substrate can be paired with dielectric insulation layers and copper traces to create a functional printed circuit board. The result is a high-performance PCB solution that meets the cooling demands of modern power electronics, LEDs, automotive systems, aerospace avionics, and more. IMS PCBs balance thermal and structural capabilities, unlike any other circuit board technology.

In this guide, we will dive deeper into what makes IMS PCBs unique. We’ll examine IMS board construction, materials, manufacturing, and applications where metal core PCBs excel. Whether you need a metal base PCB prototype designed or want to leverage IMS technology for volume production, this overview covers the key factors around insulated metal substrate PCBs.

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    What is IMS PCB?

    IMS PCB stands for insulated metal substrate printed circuit board. As the name suggests, these boards use a metal base layer as the foundation instead of the typical laminate materials like FR-4. This metal core gives IMS PCBs their distinctive properties and performance advantages.

    An IMS PCB is also referred to as:

    • Metal core PCB
    • Metal base PCB
    • Thermally conductive PCB
    • Thermal PCB board

    The metal used for the core substrate is typically aluminum or copper due to their high thermal conductivity. However, other metals can also be used depending on the design requirements.

    The planar metal layer provides the underlying support structure for the PCB. It is then laminated with dielectric insulation layers on top and bottom. These thermally conductive dielectric layers electrically isolate the metal substrate. Common materials used include epoxy, polyimide, PET, and PEN.

    On top of the dielectric layers, copper sheets are laminated to create the traces, pads, vias, and other conductive features required for the circuit board. This is similar to the layer stack-up used for conventional PCB fabrication.

    The end result is a circuit board capable of conducting heat 400-1000 times better than standard FR-4 boards. This enables IMS PCBs to dissipate heat extremely effectively from heat-generating components.

    Insulated Metal Substrate PCB
    Insulated Metal Substrate PCB

    IMS PCB Structure and Materials

    The unique properties of IMS PCBs stem from their layered construction featuring a metal core:

    • Metal Core Substrate – This forms the base of the PCB and is made of aluminum or copper that is 0.5mm to 3mm thick. The high thermal conductivity allows heat to spread through the metal layer.
    • Dielectric Insulation – This electrically isolates the metal substrate. Typical materials used are epoxy, polyimide, PET, or PEN. Multiple layers are often laminated with the metal interspersed between.
    • Copper Layers – After insulation, copper sheets are layered on top and bottom of the dielectric. These form the traces, pads, vias, and other conductive features. 1 oz to 6 oz copper is commonly used.
    • Coatings and Finishes – The top layer is coated for oxidation resistance and enhanced solderability. HASL, Immersion Silver, ENIG, and OSP are common finishes.

    The thickness and number of layers can be adjusted based on thermal and mechanical needs. Additional dielectric and copper layers can be added to create multilayer IMS PCBs as well.

    Key factors for the dielectric material are thermal conductivity, bond strength, thermal expansion, and electrical insulation properties. Common options include:

    • Epoxy – cost-effective, bonds well with metals
    • Polyimide – withstands higher temperatures
    • PET/PEN – higher thermal conductivity than epoxy

    The combination of materials is engineered to create an IMS PCB optimized for heat transfer, structural rigidity, and electrical performance.

    IMS PCB Structure
    IMS PCB Structure

    Benefits of IMS PCBs

    IMS PCBs provide several advantages that make them an attractive option for many electronics applications:

    • Thermal Performance

    The metal core substrate allows heat to spread out and dissipate rapidly. This gives IMS PCBs 400-1000 times better thermal conductivity than standard FR-4 boards. Components stay cooler, and thermal management is easier.

    • Heat Dissipation

    The heat-spreading capability enables heat-generating components to be placed more densely. Heat flows into the metal base and away from critical devices. This supports advanced thermal management.

    • Thin and Lightweight

    With a high-strength metal foundation, IMS PCBs can be fabricated thinner than typical PCBs. This allows more compact, space-saving designs. Less dielectric material also reduces weight.

    • Vibration and Shock Resistance

    The metal substrate provides enhanced structural rigidity. IMS PCBs resist flexing, vibration, and shock better than normal PCBs.

    • Design Flexibility

    IMS technology supports complex board shapes, internal cutouts, and integrated metal heat sinks. This facilitates innovative cooling strategies.

    In summary, the combination of cooling capacity, lightweight, and robustness make IMS PCBs ideal for many demanding applications. Their high thermal conductivity unlocks performance potential not achievable with standard PCB materials.

    IMS PCB Classifications

    There are a few ways that insulated metal substrate PCBs can be categorized based on their core metal and layer stackup:

    • Core Metal – Aluminum IMS PCB, Copper IMS PCB, Stainless Steel IMS PCB. Copper offers the best thermal conductivity.
    • Layer Count – Single layer IMS PCB, Double layer IMS PCB, Multilayer IMS PCB with 4, 6, 8, etc layers. More layers allow complex routing.
    • Board Thickness – Varies based on layer count. Typical range is 0.8mm to 3mm thick.
    • Circuit Type – Single-sided, double-sided, or multilayer circuit layouts. Double-sided is very common.
    • Board Shape – Standard rectangle or custom shapes with complex contours and cutouts.

    Key factors in selecting the IMS PCB type are the thermal and mechanical requirements, circuit complexity, and application constraints like weight and space. Consulting an expert IMS PCB manufacturer is recommended to determine the optimal IMS board specifications.

    LED PCB Fabrication
    LED PCB Fabrication

    IMS PCB Applications

    The unmatched thermal performance of IMS PCBs makes them well-suited for applications that require effective heat dissipation from sensitive electronics. Some of the leading uses of insulated metal substrate PCBs include:

    • LED Lighting – The high-power LEDs used in lighting generate significant heat. IMS PCBs dissipate the heat to maintain light output and lifespan.
    • Power Electronics – IGBTs, power converters, and other power devices benefit from the cooling capacity of IMS PCBs.
    • Automotive – The high ambient temperatures in automotive environments make cooling essential for engine control units, infotainment, and ADAS.
    • Aerospace/Aviation – Cooling electronics in cramped, high-altitude environments is critical. IMS offers thermal stability for avionics.
    • 5G Telecom – Dense 5G radio components need cooling as data rates increase. IMS allows packing of more components.
    • Consumer Devices – From phones to game consoles, IMS PCBs help cool compact mobile consumer electronics.
    • Medical – Analytical devices like PCR thermocyclers require precise thermal control that IMS provides.

    The above represents the industries where insulated metal substrate PCBs are most widely adopted currently. With continuing technological advances, IMS technology has the potential to expand into additional applications in the future.

    IMS PCB vs FR-4 PCB

    There are several key differences between IMS PCBs and standard FR-4 PCBs:

    • Thermal Conductivity – The metal core of IMS PCBs provides 400-1000X higher thermal conductivity than FR-4.
    • Heat Dissipation – The metal foundation allows rapid spreading and dissipation of heat vs the insulative FR-4 material.
    • Structural Rigidity – IMS PCBs are stronger and resist flexion and vibration better than FR-4.
    • Weight – IMS PCBs can be fabricated thinner and lighter than FR-4 thanks to the metal layer.
    • Dielectric Material – FR-4 uses glass-reinforced epoxy. IMS PCBs use thermally conductive polymers.
    • Cost – IMS PCBs have a higher material cost due to the metal substrate and dielectric.
    • Applications – IMS is better suited for the thermal management of power electronics, while FR-4 works for less demanding applications.

    In summary, IMS PCBs provide superior cooling capacity and ruggedness compared to standard FR-4 PCBs. Their thermal and mechanical performance makes IMS the ideal choice for heat-sensitive electronics.

    FR-4 PCB
    FR-4 PCB

    IMS PCB Manufacturing Process

    IMS PCB fabrication utilizes many of the same techniques as standard PCB manufacturing. However, additional steps are required to bond the metal and dielectric layers properly. Here is an overview of the IMS board fabrication process:

    • PCB Prototyping – The manufacturing process begins with PCB milling or CNC machining for prototype boards. This allows testing design concepts and thermal performance.
    • Metal Etching – The core metal substrate must be etched to create cutouts, cavities, and other features. Photolithography and chemical etching are typically used.
    • Surface Treatment – The metal uses chemical and mechanical processes to improve adhesion. Common pre-treatments include cleaning, abrasion, and oxide removal.
    • Dielectric Layer Lamination – Using high heat and pressure, the dielectric material is laminated onto the treated metal core. Multiple layers can be added.
    • Copper Layer Bonding – Copper foils are bonded to the dielectric layers to create the conductive layers for traces and vias.
    • PCB Imaging – Photoresist is applied, and the board is imaged to transfer the circuit pattern using lithography processes.
    • Copper Etching – Unwanted copper is removed through etching to leave only the desired conductor pattern on the PCB.
    • Plating and Coating – Platings like ENIG or HASL are applied to protect the copper and facilitate soldering.
    • Drilling and Routing – Holes are mechanically drilled and routed to create vias and cut board contours.
    • Final Testing – Electrical testing and quality inspection complete the manufacturing process before shipping.

    The specialized materials and fabrication of insulated metal substrate PCBs require technical expertise. Working with an experienced IMS PCB manufacturer helps ensure optimal results.

    JHYPCB - Your IMS PCB Manufacturer

    As an IMS PCB manufacturer, JHYPCB provides high-quality metal core, metal base PCB prototyping and production services. With advanced manufacturing capabilities and expertise, JHYPCB is a leader in insulated metal substrate PCB technology.

    JHYPCB’s capability and  technical specification

    • 10+ years focused on IMS PCB fabrication
    • Volume production capacity up to 1,000 pieces per day
    • Minimum feature size down to 3mil line/space
    • Via sizes down to 0.2mm drilled hole
    • Layer count up to 20 layers
    • RoHS-compliant and UL-certified
    • Complete quality testing and assurance
    • Materials: Aluminium & copper plates. FR-4, PTFE, thermal dielectrics.
    • Dielectric thickness: 0.05mm – 0.20mm
    • Thermal conductivity: 1-12 W/m/K
    • Profile method: Punching, Liquid cooled routing
    • Copper weights (finished): 35μm – 140μm
    • Minimum track and gaps: 0.10mm / 0.10mm
    • Metal core thickness: 0.40mm – 3.20mm
    • Maximum dimensions:  550mm x 700mm
    • Surface finishes available: HASL, LF HASL, OSP, ENIG, Immersion tin, Immersion silver
    • Minimum mechanical drill: 0.30mm
    • Minimum laser drill: 0.10mm standard, 0.075mm advanced

    JHYPCB has the technical knowledge and process controls to manufacture complex IMS boards cost-effectively. Whether you need a simple 2-layer IMS PCB prototype or multilayer metal core boards for volume production, JHYPCB can deliver quality and service.

    Contact the JHYPCB team to discuss your next insulated metal substrate PCB project and learn more about our manufacturing capabilities.

    Picture of JHYPCB - China Leading PCB & PCBA Manufacturer

    JHYPCB - China Leading PCB & PCBA Manufacturer

    JHYPCB is a China leading printed circuit board manufacturer, offering high-quality, cost-effective, and quick-turn PCB manufacturing and Assembly services from prototype to high-volume production. We understand that our customers must have on-time manufacturing and delivery of their boards. Let us help you launch products faster and more efficiently.

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