How are microchips made?

Microchips are marvels of precision engineering. They end up in smartphones, cars, or even space rockets. But it all starts from one of the most abundant natural resources on earth: sand.

Microchips—also referred to as integrated circuits, silicon or computer chips, or simply chips—are in their essence tiny sets of electronical circuits that can be used to process and store information.

Creating a functional microchip involves numerous steps, each meticulously designed to make the resulting product as small, performant, and reliable as possible. The starting material, however, is surprisingly ordinary: sand.

Sand is melted into a liquid silicon mixture, from which pure silicon can be extracted and cut into very thin slices, called wafers.

Each wafer forms the foundation for hundreds of chips, created through a repetition of steps that selectively build, modify, and remove material. This results in a multi-layered structure containing billions of electrical switches.

Step-by-step semiconductor fabrication

Step 1: Purifying silicon

Chips are made of silicon, which is derived from sand. Silicon is a semiconductor, which means it’s a material that can conduct electricity under certain conditions. Its properties are somewhat in between those of an electrically conductive material (like a metal) and an insulator (like rubber).

Depending on the temperature, for example, or on the presence of impurities, silicon can either conduct or block electricity. This makes it perfectly suited to control electrical signals in microchips.

(Most people know the word ‘silicon’ in the context of ‘Silicon Valley’, the globally renowned tech hub in the San Francisco Bay Area where many of the world’s leading tech companies and startups are based. Silicon Valley earned its name because it was at the time the center of innovation in the semiconductor industry.

Dive into the history of microchips

To create silicon chips, sand is heated to extremely high temperatures in a furnace yielding a liquid silicon mixture. Using a pure silicon crystal, the silicon can now be pulled out of the mixture. This is done in a rotating manner, resulting in a cylindrical silicon rod up to 30 cm in diameter. This rod, or ‘ingot’ as it’s typically called, is cut into very thin slices or wafers that form the primary substrate for building microchips.

Step 2: Building chip layers through deposition

Next, thin films of various materials are added to the wafer in a process called deposition, to create the layers of hundreds of microchips. Deposition can be achieved through several techniques, depending on the material that needs to be deposited.

• Chemical vapor deposition is a process where gases react or decompose onto the wafer to form a solid thin film. It’s commonly used to deposit materials like silicon dioxide.
• Physical vapor deposition involves physically vaporizing material from a source and condensing it onto a substrate in a vacuum, often used to coat surfaces with metals like aluminum or titanium.

Step 3: Drawing circuit patterns through photolithography

Next, the newly deposited layer undergoes photolithography. This crucial step defines the intricate circuit patterns on a silicon wafer. Photolithography involves coating the wafer with a light-sensitive material called photoresist.

The wafer is then exposed to UV-light through a mask or stencil containing a blueprint of the desired circuit design. As the light alters the photoresist only, the circuit pattern is transferred onto the wafer.

Step 4: Sculpting the circuitry through etching

Etching is the process of removing layers of material from the wafer using a chemical product, creating the different circuit paths. After the lithography step, material that’s no longer covered by photoresist can be etched away. This allows the desired patterns to emerge.

Step 5: Introducing electrical properties through doping

Next, the wafer undergoes a process called doping. Here, impurities are intentionally introduced to modify the electrical properties of the silicon.

Doping specific areas creates regions of positive (p-type) and negative (n-type) charge carriers, essential for forming transistors, the building blocks of microchips. The precise control of doping concentrations and locations is critical to the chip’s functionality.

Steps two to five are repeated hundreds of times, to first build the transistors onto the chips and then the metal pathways that connect the transistors.

Step 6: Packaging and protecting the microchip

Today’s chips contain billions of interconnected transistors, each between 1 and 100 nanometers in size.

One nanometer is incredibly small. It’s roughly how much your nails grow in a single second. In fact, there are as many nanometers in a millimeter as there are millimeters in a kilometer! Imagine how precise and delicate the chip manufacturing process must be to achieve such microscopic scale without error.

Even the slightest contamination could damage the delicate circuitry and compromise the chip’s performance. That’s why the manufacturing process takes place in a highly specialized cleanroom.

After passing a series of rigorous tests, each wafer is cut into small pieces, resulting in individual chips. These chips are then encased in a protective package that shields them from environmental damage and facilitates their integration into electronic devices.

The packaging process also includes attaching the chip to external pins or connectors. This allows it to interface with other components in a device.

A semiconductor ecosystem

The actual production process of microchips is only part of the story. The devices, materials, procedures, and methods that come into play all require highly specific and innovative technology and craftsmanship. It all starts from smart integrated circuit design.

What is integrated circuit design?

Integrated circuit (IC) design is the process of creating the layout and structure of a microchip. This includes the arrangement of transistors, resistors, capacitors, and other components that control, limit and store electrical energy.

Based on what the chip needs to do, for example process data, store memory, or manage power, chip designers need to take into account performance requirements and necessary features. They develop circuit diagrams (schematics) that specify all the components, logical operations, and electrical characteristics of the circuits.

Next, these circuit diagrams are translated into a physical layout, of how all components will be placed on a silicon wafer and connected by tiny wires or traces. Here, it’s important to minimize space and optimize for performance, power consumption, and manufacturing efficiency.

Once the design is finalized and verified through simulations and tests, it’s sent to a semiconductor foundry (fab) where the integrated circuit is manufactured.

A global network

• Everything starts with research and experiments on new devices, materials, and procedures. All players active in the semiconductor industry work together with researchers in Belgium to develop the chips of the future.
• The blueprints for the chips of the future are designed by skilled experts, with major chip designers based in Silicon Valley in the US.
• Building billions of electronic circuits with nanometer precision requires extremely advanced lithography machines that are developed in The Netherlands.
• Finally, producing chips requires highly specialized fabrication facilities or fabs. All of the world’s most advanced processing chips are built in Taiwan, while South Korea specializes in manufacturing advanced memory chips. Many other players in Europe, the US and Asia produce less complex semiconductor components and chips for specific applications.

In other words, the chip technology ecosystem is a vast and interconnected network involving numerous stakeholders, from research institutions and material suppliers to equipment manufacturers and end-users.

The complexity of this ecosystem can be compared to assembling a global puzzle. Each piece plays a crucial role in creating the powerful chip technology that drives our modern society.

Innovation through collaboration

The chip technology ecosystem is constantly evolving, driven by the relentless pursuit of better, smaller, and more sustainable chips. These help us to not only build better cell phones, laptops, or home appliances. They also enable smaller and cheaper diagnostic devices, or safer transportation. All of these applications require enormous computational power and increasingly powerful chips.

Imec, a world-leading research and innovation hub in nanoelectronics and digital technologies, plays a crucial role in advancing microchip technology. True to its mission as global chip innovator, imec gathers all companies in the chip industry, including competitors, to work together on the technology of the future. By pushing the boundaries of what’s possible and by enabling global collaboration, imec’s research focuses on developing new materials, processes, and designs that will power the next generation of microchips that are both more powerful and more sustainable.