A microchip processing consists of only two types of operations to either deposit something or remove something. Nothing more than that. Modern microelectronic production is mainly based on processes using plasma. Even if we take into account diffusion and some other wet processes, plasma remains the main instrument in microelectronic manufacturing. In this article, we want to analyze the plasma-based processes using 9 Windows and predict what will replace the plasma in microchip manufacturing.
9 Windows is an excellent tool that helps us think in space and in time. This tool helps us to predict the future.
Analysis using 9 Windows
9 Windows is a simple to use creative thinking tool. All we need is 3 X 3 matrix to get 9 fields. An example of 9 Windows is shown on the image below:
The horizontal axis is TIME that is represented in three phases: PAST, PRESENT, and FUTURE. An example: PAST – Seed, PRESENT – Tree, FUTURE – Fruits
The vertical axis refers to SPACE and represents three parts: SUBSYSTEM, SYSTEM, and SUPERSYSTEM. These are also related hierarchically: Subsystem is a part of the System, while System is a part of a Supersystem. An example: SUBSYSTEM – Leaf, SYSTEM – Tree, SUPERSYSTEM – Forest.
Next, we need to fill in all the 9 windows in the sequence as shown in the image above. The order helps us to organize thoughts and even to predict the future.
The first step is Plasma at Present System:
The Subsystem at present are radicles and ions:
The third step is the present supersystem. Plasma provides heating of the wafer surface, that is actually two-dimensional heating – 2D treatment:
In the past the system was “Hot gases”:
The components of hot gases are molecules and atoms, so let’s mention in in the Past – Subsystem window:
Before the creation of plasma, all processes were conducted in ovens that provided volume heating – 3D treatment:
Let’s have a look at the past and present and try to predict the future. It seems to be very clear.
Subsystem sequence leads to a usage of electrons (maybe very small ions) in the future:
Supersystem sequence definitely leads to single dimension heating – 1D treatment:
So our Future System that will replace plasma will be Electron beam – Electron or very small ions jet:
How the question is how the electron beam can help us and how can it replace plasma. If we think about it, the only thing that plasma is doing is providing heat. So, the process needs to heat a surface in certain location. This is definitely possible using an electron beam, similar to the old TV-sets.
We are not talking about Electron Beam Lithography (EBL). Not at all. We propose to eliminate the lithography all together.
An electron beam should be used as a movable heater. The localized heat will cause an interaction in certain areas. It could be used for both etch and deposition depending on the gases in the chamber:
The process seems to be slow. And that is true. But this solves another problem for us.
Which way is correct?
We will leave this one to you. What should be the next step in lithography? Either move to EUV (extreme ultraviolet) lithography or eliminate the lithography as the blocking process.