Posts

Etching: Digging nanoscale trenches

Image
Beginner's introduction to etching. To lay underground cables, pipes, building foundations, and other such structures, we need to dig the ground up and then lay them below the surface. A loose connection during laying can mean either digging up the place again, or in the case of building foundation, keep reinforcing the structure to keep it from falling. A well dug-in pipe or a cable can last for a very long time. A strong foundation makes for a sturdy building. Etching aids in the formation of lasting layers of a semiconductor device. Figure 1: Location of etching in process flow. Etching is the process of removing unwanted material from the substrate. There are some portions that need insulation in a conductive layer and some places which may require conductive material deposited into an insulating layer. Removing that part and subsequently depositing the required material is where it finds its use. For all of our life on this planet, you can only exist in two states: wet or d...

Deposition: Rich man’s brick laying

Image
Starter's first deposition. Construction is something that everyone of you has witnessed time and time again. Most of these buildings are made of brick and concrete. Concrete acts as the adhesive, joining the bricks together. Deposition is the construction of semiconductor manufacturing. Basic understanding of it is constructing thin films by laying atoms on a substrate. Atoms are the bricks and the bond between the atoms is the concrete. Figure 1: Location of deposition in the process flow. This topic is an absolute mammoth to cover due to the number of techniques and materials that can be laid on top of one another in such a minuscule scale. The huge range and properties of materials, whether they be elements or compounds, calls for multiple processing procedures. One technique may work for one material and may completely fail for the other one just due to a difference in melting point. There are three basic deposition principles: physical deposition, chemical deposition, and...

Doping: No, not the illegal in sports kind

Image
The beginner's post for doping. The first thing in your mind was probably the infamous incident of Lance Armstrong being caught using performance enhancing drugs during the Tour-de-France. Using these sorts of drugs is completely banned in sports and to enforce this the World Anti-Doping Agency was founded. In the context of semiconductors; doping is one of the most useful processes invented and has been utterly crucial in shaping the digital age. Let me ask you a question, what is a semiconductor? It is a material with its conductivity value in between conductors (like copper, aluminum, and other metals) and insulators (like glass, PVC, ceramic, etc.). By definition, it seems like a pretty useless material. It is an inferior conductor and an insulator. Yet, the world runs on this stuff. Why is this the case? The main property of a semiconductor is that we can change its conductivity by either optical or thermal excitation (heating or shining a light), or by doping. It follows ...

Lithography AKA Rock Drawing

Image
Here begins the beginner's guide to lithography. Yes, that is what the name means if you separate ‘litho’ and ‘graphy’. Doesn’t seem that scary now does it? The name is very literal to the process conducted. The rock in question is our silicon wafer and we create patterns on it for further processing. It is a very crucial process as it directly determines the transistor density which is directly proportional to the amount of data it can process at a time. Patterns are either printed or written on the wafer. Let us go through the process step by step. Figure 1: Process of lithography. First, we coat the wafer in a liquid state compound called photoresist. As the name suggests, this compound changes its properties when light is shined on it. The wafer is then spun around for a determined time and rotations per minute to ensure uniform coating. The same way we use our handheld utensil (I don’t know what you use) to evenly coat bread with butter or jam so that we get every flavored b...

Memory Bankruptcy; the curse of corpo preorders and our willing descent into oblivion

Image
“Hey sorry I forgot this task, it slipped from my mind,” a perfectly normal occurrence in day-to-day life but when your computer forgets a piece of information then it becomes a DEFCON 1 situation. Your computer also has the same sort of architecture your brain uses. A signal is received, your brain searches for instructions and stores some information vital for the time being as temporary memory, then a response where you perform an action and maybe you store the action in your doubtful permanent memory. Computers work the same where some memory is volatile, as in it is lost when power is switched off, and some is non-volatile, remains even after power loss. Non-volatile memory is your solid-state drives (SSD), hard disk drives (HDD), CDs, pen drives, and SD cards. Volatile memory mostly consists of Random Access Memory (RAM). RAM is your temporary memory that is used during the process and forgotten afterward. For the purposes of this article there is no need to go into detailed work...

Semiconductor Arms Race: The New Black Gold

Image
Chippy-chip-chips, a very simple word to describe what is probably the single greatest interdisciplinary scientific and engineering accomplishment till date. These small things that seem like toys or actual potato chips are responsible for around, let’s see here… I would like you to just think what you are reading this post on. If you don’t mind, please open the app that records your screen time, or maybe tell me the last time you might have paid in cash, I guess if you deal in black money that shouldn’t be a problem, but for a poor student like me I have trouble thinking the last time I transacted using printed currency. Figure 1: Basic overview of various manufacturing components  Reference: Semicon Talk on YouTube Semiconductors dictate your life, around 50 percent of your day is occupied by electronic devices because it is just so convenient. I would like to eat something new, just order it, or if you feel creative enough, look up a recipe. I need ingredients for the recipe, or...

Decoding the Clean Room; more than meets the eye

Image
In all your time on the internet you must have come across a term called ‘semiconductor manufacturing’ or an Instagram reel telling you about the size of a microprocessor. You might have wondered in what conditions does this manufacturing occur. A nanometer is a billionth of a meter, at that point you are closer to an atom than to a dust particle. Controlling the conditions of your space becomes very crucial when working at such unimaginably small scales. So where does the magic happen? A clean room is a room that is first and foremost clean. Wow Arjun, thank you for stating the obvious we would never have figured it out. I tell you most of the stuff you see that you might think is complicated has a very obvious name. The thing that actually scares everyone are the scientists’ and physicists’ names attached to the effect/phenomenon. The dirtiest entities inside the room will be us, humans. We carry dust, dirt, grime, even our hair is enough to kill any device we may be trying to fabr...