Understanding the Lifecycle of IC Chips: From Design to Disposal

Image source Semiconductor Engineering

In recent years, IC chips have attracted full attention around the globe. This is because of the important roles that they play in different application areas.   The recent events of the IC chip shortage have forced all the key players to focus on various stages of IC production.  Users of the semiconductor chip wanted a clear explanation for the shortage. They were no longer comfortable sitting at the tail-end of the supply chain and waiting for the semiconductor chips to be supplied.

The lifecycle of IC chips encompasses a series of actions and events. Many players are involved and critical decisions have to be made. By the time the chip is delivered to the market, it must have gone through all the stages in the lifecycle. In most cases, all the steps are similar only that there could be some slight variations depending on the specifications and the manufacturer. In this guide, we are going to break down the lifecycle of IC chips, from the design to disposal.

Step 1: IC chip design

 Now that you have decided to build semiconductor chips, one of the very first moves is coming up with an appropriate design. Just like when building any other product, the design will determine the final outlook of your semiconductor chip. The design process has to take care of the fact that semiconductor chips house thousands of electronic components. This alone can make it difficult to come up with a perfect design that will be able to cater to all these components.

The semiconductor chip design process  is broken down into five key steps which are as follows:

Architectural design:

This stage of the IC design process entails defining and collecting all the requirements for the semiconductor chips you would like to develop. All the components that you will need in other steps of IC manufacturing are named in this stage. For this to be done correctly, you will have to craft a series of questions that will define the direction of the manufacturing process: What is the purpose of the IC chip that you are building? What kind of performance should I expect from the chip? What is the budget of the chip? Where is the chip intended to be used.? Once you get the answers to these questions, you can proceed to the next stage of the semiconductor chip design process.

Logic and circuit design

Now that you know your exact needs and wants, the next step is to transform those wants into building blocks for the IC chips. You will build a logic circuit. In the past, the process of implementing logic and circuit design was done manually. It entails determining the connections and placement of the electronic components on the semiconductor wafer.

Thanks to technological advancement, creating logical design is a fully automated process.  Furthermore, there are specialized simulators that create complete simulations of the integrated circuits. They help designers figure out the components' exact placements and interconnections. After the design, you can also use the simulators to have a preview of the expected performance. 

Physical design

The physical design phase of the semiconductor chip design process entails building the actual physical layout based on the logical design. The step entails creating the actual shapes, and the components that will be on integrated circuits.

The physical design process starts with determining the size and shape of the modules that will be on the semiconductor chip. To do this, you will have to know the total surface area of the chip. The goal is to have a proper placement of the electronic components. They should not be crowded in one place as this will hinder the performance.

Another goal of physical design is to have an optimized connection. A well-established interconnection between the components will boost the performance of the integrated circuits. It also takes care of the safety element of the semiconductor chip.  Keep in mind that the architectural element of the IC chip must be reverified after every step of the physical design.

Physical verification

From this name, this process of IC design process entails verifying all the aspects of the physical design process. The core purpose of physical verification is to verify that the designed chip will be fully functional and perform to the required standards.  Will the design guarantee the high performance of the chip under strenuous conditions? Will the design improve the reliability of the chip? Will the design make it possible for the IC chip to be used in specific application areas? These are just some of the important questions that the physical verification process intends to answer.

Design sign off

This is the last step of the semiconductor chip design process. It entails confirming that the design meets all the required parameters for the integrated circuits. Common parameters include power consumption, clock cycle, frequency, and signal integrity, among others. Manufacturers use this step of the chip design process to gauge the expected performance of the chip. In case they are not fully satisfied, then some aspects of the design will have to be redone.

Step 2: Chip Manufacturing

From the design process, the IC chip is forwarded to the manufacturing phase.  Different methods and techniques are involved in the semiconductor chip manufacturing process. One is photolithography, which entails printing the circuits onto silicon wafers. Also known as optical lithography, the process entails using light energy to transfer a pattern onto a silicon wafer. For this to happen, a photosensitive material is applied to the silicon wafer. A photomask that contains the pattern is then placed on this photoresist. The photolithography is then applied to the photoresist material. It will weaken or harden the photoresist depending on the pattern that you have created, which will be based on the component placement and circuit design.

Etching is the next process of the IC manufacturing process. Here, the weakened sections of the photoresist are removed. The removal exposes the silicon crystal which is usually doped with impurities to enhance their conductivity and also create various microelectronic components. The result is the creation of complete electric circuits.

The circuits are printed either on one side of the wafer or on both sides. The etch process must be done with high levels of accuracy to preserve the consistency of the chips. Also, the fact that a chip may comprise several layers means that etching should be controlled to minimize any form of physical and electrical damage.

Ion implantation

This is another critical process that is embedded in the IC chip manufacturing process It is done immediately after the etching process.  After the defined patterns have been etched onto the wafer, the latter may end up having positive and negative ions which will end up defining the electrical properties of the pattern. Keep in mind that raw silicon is a semiconductor and hence may not be an ideal conductor or an insulator.

During the ion implantation process, charged ions are directed into the silicon crystals. This makes it possible for the normal flow of electrons to be controlled by components such as transistors. After the implantation of ions, the remaining sections of the photoresist material are modified and sometimes even removed.

Step 3: Chip Packaging

Packaging silicon semiconductor chips is more complex than you can imagine. Unlike other products, it is more than just putting a chip into the packaging material. First, the chip has to be extracted from the silicon wafer. This is done by carefully slicing it using a special tool.  Usually, the cutting process focuses on individual chips that are laid on the wafer. In some cases, a wafer may contain several layers of individual chips.

Once the chip has been extracted, it is placed onto a substrate.  This is a special type of board that is used for packaging integrated circuits. It contains metal foils that facilitate the connection of a chip to other parts of an electronic device when the chip has been finally integrated into the real-world application.

A heat spreader is placed on the top of the chip to act as a lid. This is a metal protective container that has desirable temperature properties. It ensures that the chip stays cool and dry when in operation and even when not used.

Step 4:  Testing

Testing is an important part of the IC chip lifecycle. The primary goal of the testing process is to ensure that everything works perfectly and smoothly as expected. You don’t want to release defective chips to the market as this will ruin the reputation of your brand.

Different types of tests are conducted on an integrated circuit chip. They include wafer tests, circuit tests, probe tests, and packaging tests. The types of tests being conducted may vary depending on the specifications of the integrated circuit. In case the chip does not pass the testing requirements, it can be taken back to the production cycle or it can be disposed of.

I hope that with this guide, you have an idea of what the lifecycle of IC chips entails.  Once everything is done, the chips finally find their way to the supply chain where reputable IC suppliers distribute to the market.