Semiconductor manufacturing is an extraordinarily precise process that turns a single wafer into hundreds or even tens of thousands of individual chips. It’s not uncommon for the entire process, from start to finish, to involve anywhere from 1,000 to 3,000 individual steps.

 

At a high level, the process is divided into two major stages:

・Front-end processing (wafer fabrication: creating transistors and wiring)

・Back-end processing (packaging: sealing, mounting, and testing)

In front-end processing, transistors (the active devices) are formed on the wafer, and wiring (the circuitry connecting them) is created.

FEOL (Front-End Of Line: device formation)

The stage in which transistor structures — such as MOSFETs, FinFETs, and GAA devices — are formed. This includes processes such as oxidation, film deposition, exposure, etching, ion implantation, and annealing.

 

BEOL (Back-End Of Line: wiring formation)

The stage in which transistors are connected together using copper wiring. Low-k dielectric layers and metal wiring are stacked to complete the circuit.

In back-end processing, the wafer produced during front-end processing is cut into individual chips, sealed within a package, and subjected to final testing.

 

The main steps include:

・Dicing (cutting the wafer)

・Packaging (wire bonding or flip-chip mounting)

・Mounting onto a substrate

・Functional testing (FT) and electrical testing (E-Test)

 

By the end of this stage, the wafer has become a finished, shippable product.

The overall manufacturing flow can be summarized as follows:

Front-end processing

1.Wafer fabrication (Si / SiC / GaN)

2.Oxide layer formation

3.Film deposition (CVD / PVD / ALD)

4.Resist coating

5.Exposure (ArF / EUV)

6.Development

7.Etching

8.Resist stripping

9.Ion implantation (doping)

10.Annealing (activation)

11.CMP (planarization)

12.Wiring formation

13.Multilayer wiring (BEOL)

 

Back-end processing

1.Dicing

2.Packaging

3.Mounting (onto a substrate)

4.Electrical testing

5.Shipping

 

Throughout this process, semiconductors are built up by repeating the sequence of film deposition → exposure → etching → planarization dozens of times over.

(1) A form of manufacturing built by stacking layers into an extremely three-dimensional structure

By repeating the cycle of thin-film formation, patterning, removal, and planarization, circuits are gradually built up into a complex three-dimensional structure.

 

(2) Yield is the single most important metric

Because tiny particles, residue, or even slight variations in film thickness can cause defects, extremely rigorous process control is required.

 

(3) The cleanroom is the lifeblood of manufacturing

Since human beings are, in many ways, the greatest source of contamination, extremely strict environmental control is required — often at Class 1 to Class 1000 cleanliness levels.

 

(4) Semiconductor manufacturing is also a massive equipment industry

Leading equipment manufacturers from around the world play essential roles — for example, ASML in lithography, and Tokyo Electron, Lam Research, and Applied Materials (AMAT) in deposition and etching.

Semiconductor manufacturing proceeds through the following stages:

・FEOL (device formation): Creating transistors such as MOSFETs.

・BEOL (wiring formation): Connecting transistors together using copper wiring.

・Back-end processing (assembly): Dicing into chips, sealing, and testing.

 

Through these three stages, the wafer is gradually transformed into a finished product.

・Semiconductor manufacturing is broadly divided into front-end and back-end processing.

・Front-end processing involves forming transistors and wiring.

・Back-end processing involves packaging and final testing.

・Throughout the entire process, cleanliness, yield, and equipment management are all critically important.

Q1. What are the two main stages that semiconductor manufacturing is broadly divided into?

Q2. Explain the difference between FEOL and BEOL.

Q3. Why is the cleanroom so important in semiconductor manufacturing?

 

Column Supervisor: Koji Kakumoto (Otis Group Co., Ltd.)

After studying abroad and working in planning and development at a trading company, he joined Otis Group Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as Representative Director, working to drive business growth and strengthen the organization.

 

This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.