Semiconductor Manufacturing – Part 2

The post on Processors & Microfabrication was a brief but helpful refresher on the current state of the art in microfabrication. I have found some (more current) interesting videos on chipmaking this past week. After reviewing an introduction to manufacturing, I found myself wondering which area of manufacturing would be interesting to me (one of the chapters had a question like that). It hit me that fabs are the only manufacturing industry that seem really intriguing at this point (perhaps based on my background in computer science). Therefore, I have been trying to get up to speed with what’s happening in semiconductor manufacturing.

The first video on chipmaking in TX gave me a good sense of how many companies are in this space. Learning that the integrated circuit was invented at Texas Instruments leaves me surprised at how little I know about the history of chips. Some of the companies manufacturing chips in TX are Samsung, Texas Instruments, Infineon, Global Wafers, NXP, and Applied Materials. TI mentions their Power management solutions as part of the vast reach of their products. The video highlights the importance of space, power, and water.

How Texas Became The American Chipmaking Hub

Micron is the focus of the following video. It has a fascinating history, having been founded in the basement of a dental office in Boise, ID. Something that stands out to me in the document showing 2.1 million common shares when Micron went public in 1984 is the now infamous Lehman Brothers. It’s interesting seeing the distribution of market share across memory manufacters: Samsung, SK hynix, and Micron sharing about 94% of market share. The rest is split into slivers taken by Winbond, PSMC (powerchip.com), CXMT, and others. I haven’t paid much attention to the memory industry, so HBM3E | Micron Technology Inc. is new to me. I was also surprised to learn that the cost of power is lower in the US than in Asia. How cool is it that Micron also runs a chip camp?

Micron HBM3E 8-high 24GB will ship in NVIDIA H200 Tensor Core GPUs starting in the second calendar quarter 2024.

HBM3E | Micron Technology Inc.

The next video is yet another overview of semiconductor manufacturing. One of the key takeaways for me is that Taiwan leads not just in logic (CPUs, GPUs, etc) but also in memory, courtesy of Micron! 25% of Micron employees are in Taiwan, producing 65% of Micron’s DRAM!

Inside Micron Taiwan’s Semiconductor Factory | Taiwan’s Mega Factories Ep.1

This next video is a survey of the intense competition in the semiconductor industry given its significance in the modern economy. It covers topics like how and why the chips act was passed. See FACT SHEET: One Year after the CHIPS and Science Act, Biden-Harris Administration Marks Historic Progress in Bringing Semiconductor Supply Chains Home, Supporting Innovation, and Protecting National Security | The White House for the PR side of it from the white house. One of the speakers is the author of Chip War: The Fight for the World’s Most Critical Technology: Miller, Chris: 9781982172008: Amazon.com: Books. Sounds like good reading for this summer.

The race for semiconductor supremacy | FT Film

Categories: Mechanical

Flanges and Gaskets Introduced

I have learned about various software packages this year. One of them is SolidWorks 2023. The tutorials I worked through started with how to model a flange. I figured I should probably know exactly what these are used for. Here’s a good video explaining what flanges are and the various types of flanges.

Piping Flange Types, Faces, and Surfaces – Explained!

One of the concepts introduced in this video is a gasket. I’ve heard the term used a lot but never really paid attention to exactly what a gasket is. This was a helpful breakdown of gaskets: Types of gaskets and gasket fundamental. – YouTube.


Categories: Digital Logic

Tristate Buffers & Impedance

Learning more about computer architecture has rekindled in me an interest in digital logic. I was perusing the Introduction to Logic Synthesis Using Verilog HDL book when I encountered tristate buffers – one of the less obvious circuit components to me. YouTube proved to be a valuable resource (as it often does) with a variety of explanations about what they are and how they are used. Below is my favorite video on the topic.

I wanted to learn more about the concept of impedance since the high impedance mode is one of the tristate buffer states. Wikipedia’s article on Electrical impedance seemed a bit much for the high level overview I sought. Back on YouTube, I found this video that, while not focussed on digital circuits, was quite interesting. It got me to order a P3 P4400 Kill A Watt Electricity Usage Monitor for myself.


Categories: Circuit Boards

Motherboards

I recently bought the Skytech Blaze 3.0 High-Performance PC Desktop, my first desktop purchase since 2010. The ASRock B550M-C motherboard caught my eye as I was looking around at the components in the desktop. Figured I might as well learn the basics of how motherboards are made (and in the process, a brief history of motherboards). Here are some videos I watched to learn about these topics.

Motherboards Explained

Manufacturing Process


Thermal Oxidation

One of the key lessons from reading about oxidation was that Si has a key advantage over other semiconductors – it oxidizes much more readily thereby simplifying the development of insulation. I was looking up videos on the Deal-Grove oxidation model law when I stumbled into these videos by Chris Mack from a microfabrication course at the University of Texas at Austin using the same Microfabrication book I’m reading! It’s amazing how much free content there is out there.


Diffusion

Diffusion is a key step in wafer processing for microprocessor manufacturing. Fick’s laws are therefore an important component in understanding diffusion. Fortunately, there are great resources online for an overview of Fick’s law. I started with the Khan Academy video on Fick’s law of diffusion (embedded below). It was informative but did not go into the level of detail I had hoped for.

Some digging around led to a series of lectures from the Mechanical Engineering’s Fertig Research Group at the University of Wyoming. This video on the mathematics of diffusion (Fick’s 1st law) was the level of detail I was hoping for and was therefore a good supplement to the Khan Academy diffusion overview.

And here’s the video on Fick’s 2nd law (again showing how to derive it and some brief comments about PDEs). I wonder if there is some accessible visualization that could be done of various solutions to the diffusion PDE.


Semiconductor Substrates – Czochralski Growth

Here is a very helpful video I found on Czochralski Growth. Some concepts that come up include nucleation, meniscus, segregation coefficients, and Lorentz force.

Dislocation loops can form if the pull rate is too low. Here is a discussion about dislocation loops.

Czochralski growth also turns out to be an interesting area for numerical modeling. I stumbled into some interesting papers when searching for more information about pulling rates. The paper that exposed me to this area is Numerical modeling of Czochralski silicon crystal growth and has various interesting citations as well.


Semiconductor Substrates – Crystal Defects

Crystal defects play an important role in semiconductor fabrication. One type of defect is a Frenkel defect. Understanding such defects involves determining the vacancy concentration as given by Arrhenius function. I reviewed several videos to help me understand this equation:

Background Concepts

I took a detour to remind myself about activation energy, electron volts, and Boltzmann’s constant (all of which feature when studying Arrhenius function).

Line Defects

Another type of crystal defect is a line defect, e.g. edge dislocation. These videos contain additional information about edge dislocations.

Area Defects

A stacking fault is an extra plane of atoms. Some resources about stack faults:

Gettering is a process by which impurities and defects diffuse through the crystal (controlling where defects occur). This can be used to improve yield in semiconductor manufacturing as explained in this video:


Semiconductor Substrates – Crystallagraphy

The previous post outlined my introduction to materials science with interest stemming from applications in microfabrication. Reading section 2.2 of Fabrication Engineering at the Micro- and Nanoscale left me curious for more information about crystal structures. A YouTube search for “face centered cubic structure” led me to the videos below, which proved sufficient for gaining a basic understanding of crystal structures.

Unit Cell Chemistry Simple Cubic, Body Centered Cubic, Face Centered Cubic Crystal Lattice Structures

How To Make Face Centered Cubic Crystal FCC By Using Ball and Stick Chemistry Molecular Models

Coordination number of Simple cubic, FCC, BCC and hcp lattice

Miller indices

These are also discussed in section 2.2 of the text and are explained in these videos. Interestingly, neither of the videos mentioned the fact that the plane notation also denotes a vector (from the origin) that is perpendicular to that plane!

Miller Indicies Practice Examples

Crystallographic Planes


Categories: Microfabrication

Semiconductor Substrates – Intro to Materials Science

An important concept when working with materials is how to represent their properties. Phase diagrams are often used for this. I have found watching lectures to be an easier way of getting into a field as new (to me) as microfabrication. This Intro to Phase Diagrams {Texas A&M: Intro to Materials} video, for example, was an easier introduction to the topic than the notes in the microfabrication book I was reading.

This video was also my first introduction to the types of issues studied in the materials science space. The next topic in the microfabrication book I was reading was crystallography. I wanted to get an overview of the area before delving into the microfabrication aspect of crystallography. A YouTube search led me to this Lecture – Intro to Crystallography from my alma mater (interestingly, from the materials science department again)!

After watching these videos, I did a quick search for material science in the Amazon books section, hoping to see the types of topics people study in this field. Materials Science and Engineering: An Introduction looks like a great candidate (cost aside)! Looks like this is an area folks in semiconductor manufacturing need to have a handle on… More to come on crystallography as it pertains to semiconductors.