Keywords: IC packaging substrate

Laminate substrates, lead frames, bonding wire, encapsulating materials, underfill, die-attach materials, WLP (Wafer-Level Packaging) dielectrics, and WLP plating chemicals are among the most common materials used in integrated circuit packaging. These materials are used to shield and link IC chips to external devices such as printed circuit boards (PCBs), as well as to provide thermal control and support. 

Because laminate substrates account for the vast majority of the IC packaging substrate industry, we'll go over them in further detail. Integrated Circuit (IC) substrates are the foundation materials used in IC packages that safeguard and facilitate connections between the IC and the trace network on the PCB. These substrates include numerous layers, a supporting core in the center, a network of drill holes, and conductor pads, making them more difficult to manufacture than traditional PCBs. 

Classifications of IC Substrates

IC substrates can be classed according to materials, structure, and fabrication techniques. Below are some typical classes of IC substrates:

• Material-Based Classification: Including silicon, ceramic, and organic materials such as polyimide, FR4, or BT resin, IC substrates can be built of a variety of materials.
• Structure-based classification: single- or multi-layer are the two categories of IC substrates. Single-layer substrates are used in the Low-density circuits and high-density circuits employ multi-layer substrates.
• Manufacturing process-based classification: the manufacturing method used can determine the classification of IC substrates. The method may be semi-additive, additive, or subtractive.
• Technique-based classification: The technique utilized like wire-bonding or flip-chip technology shows the classification of IC substrates.
• Application-based classification: Their applications used like power devices, CPUs, memory, sensors, and others also classify IC substrates. The appropriate IC substrates are chosen for a certain application as per the reliability, performance, and cost with the help of these categories.

IC substrates are divided into three categories: package or packaging type, bonding method, and material attributes/characteristics.

Packaging type

The IC packaging substrate type describes the carrier used for the IC substrate. There are various sorts of packages or packing, including:

• Ball Grid Array IC Substrate: This substrate is suitable for integrated circuit packages with more than 300 pins. It provides good electric performance and heat dissipation.

• Chip-scale packaging IC substrate: This form of substrate is tiny and thin, making it ideal for single-chip packages with a low pin count (CSPs).

• Flip-chip IC substrates: Flip-chip IC substrates are best suited for controlled collapse chip connections in a flip-chip chip-scale package (FCCSP). It provides effective heat dissipation protection against circuit loss and signal interference.
• Multi-chip module IC substrate: This style of packaging contains numerous ICs, each with a distinct purpose. The substrate must be lightweight, yet owing to the nature of MCM ICs, it may not have excellent routing, heat dissipation, or sound signal interference.

Bonding Technology

This refers to how an integrated circuit connects to the packaging or external circuitry. Bonding technology is classified into numerous categories, which include:

• Wire Bonding: The most common kind of bonding involves threading wires from the chip's connectors to the package/carrier or external circuit.
• Tape Automated Bonding (TAB):  The term "tape automated bonding" (TAB) describes the                 method of connecting an integrated circuit to fine conductors in a substrate made of polymers to create flexible printed circuits (FPC).
• Flip Chip (FC) bonding: Flip Chip (FC) bonding is typically aided by the use of solder balls/bumps to form interconnections. The bond can be formed via a polymer glue, welded junction, or solder contact.

Material Attributes

Material requirements for integrated circuits vary based on their function. The following are a few of the most popular substrate materials:

Resin is used to make rigid substrates and might include Bismaleimide Triazine (BT) Film (ABF), Epoxy, or Ajinomoto Build-up material.

• Polyamide resins or polyimide materials are used in Flex substrates. Both of them show similar thermal expansion coefficients and electrical properties.
• Ceramic material, such as aluminum oxide, silicon carbide, or aluminum nitride is often used to make this sort of substrate.

Laminated substrates Applications

In the electronics sector, Laminate substrates offer a huge scope of applications. IC substrate PCB’s most popular applications include: 

• Microprocessors: microprocessors, the brains of electronic gadgets, employ IC substrate PCBs frequently. The microprocessor operation has the PCBs as a vital component as they facilitate a strong base for the microprocessor chips attachment.
• Memory modules: memory modules make use of the IC substrate PCBs. The Memory modules are vital parts of electronic gadgets. For attaching memory chips, these PCBs serve as a substrate. They also assure the efficiency and reliability of the memory modules.
• Consumer electronics: Consumer electronics such as laptops, tablets, and smartphones use IC substrate PCBs in them. These PCBs provide a small and lightweight base for installing the device's different components.
• Industrial electronics: A vast number of industrial applications, including control, robotics, and automation use IC substrate PCBs. For attaching the many electrical components included in these systems, these PCBs offer a dependable and robust substrate.

For other electronic components, infotainment systems, and engine control units, automotive electronics employ IC substrate PCBs. To endure the demanding conditions of automotive applications, these PCBs are engineered while providing efficient performance.

Features of laminate substrates

An integrated circuit substrate (IC substrate) is a critical component in electronic devices, and it has numerous basic properties that are required for its proper operation. Some of the primary properties of an IC substrate are:

• Electrical characteristics: The electrical properties of an IC substrate are important to its successful operation. The substrate, for proper signal transmission, must have enough signal integrity and minimum electrical resistance.
• Thermal conductivity: To efficiently disperse heat generated by the ICs, IC substrates must be very thermally conductive. This feature prevents overheating and malfunctioning of the ICs.
• Mechanical strength: During assembly and handling, the IC substrate endures physical shocks and stress.  Thus, it must be extremely strong.
• Dielectric properties: For maintaining signal integrity and minimizing signal loss, the IC substrates must have a high dielectric constant.
• Chemical resistance: Throughout the testing and manufacturing procedures, the IC substrates get exposed to different chemicals. Thus, it must be highly chemical resistant.
• Surface qualities: For adhering of bonding wires and thin-film layers to be deposited, an IC substrate's surface must have high adhesion properties.
• Compatibility: For efficient performance and operation, the IC substrates and the IC packaging technologies must be compatible with each other.
• Cost: The IC substrate must be reasonably priced for the cost-effective finished electronic device.

Conclusion

This thorough tutorial covers all elements of IC packaging substrate, which are comparable to PCB substrates but more specialized owing to their size and materials. The successful fabrication of IC and PCB substrates necessitates an expert manufacturer that can obtain the best materials and use cutting-edge technologies to make excellent circuit boards. To endure the demanding conditions of automotive applications, these PCBs are engineered while providing efficient performance. For other electronic components, infotainment systems, and engine control units, automotive electronics employ IC substrate PCBs. To endure the demanding conditions of automotive applications, these PCBs are engineered while providing efficient performance. Integrated Circuit (IC) substrates are the foundation materials used in IC packages that safeguard and facilitate connections between the IC and the trace network on the PCB.