TSMC's Chen Ping: Three magic weapons that semiconductors will rely on in the future

"Major inventions in every period will change our lives. Steel in the 19th century, cars and airplanes in the 20th century, etc., have promoted development while also allowing society to flourish. What is most important to mention is the invention of the semiconductor transistor in the mid-20th century. This invention has brought about tremendous changes in society. IT technology based on semiconductors has turned the world into a "village", and mankind has entered the Internet age since then." At the 2019 Cross-Strait Integrated Circuit Industry Cooperation and Development Forum, Chen Ping, Vice General Manager of Business Development for TSMC China, talked about the impact of technology on society.

The emergence of semiconductors has completely changed our lives. Integrated circuits have only been developed for 60 years. When they first appeared, the global production scale was only a few thousand to tens of thousands of units per year. Since the 1970s and 1980s, electronic devices have become popular, and the production scale has reached hundreds of millions per year. In recent years, consumer electronics such as mobile phones have become popular, and the annual production scale can reach billions. Human life is constantly changing, and the increasing demand is constantly driving the emergence of new technologies, such as mobile terminals, high-speed computing platforms, IOT, and autonomous driving, which have brought countless business opportunities.

The semiconductor industry has a strong driving force for development, and the reason is nothing but human beings' yearning for a better life, Chen Ping said. In the past decade, the rise of smart phones and the Internet has driven tremendous changes in society, so society's expectations for semiconductor technology are increasing day by day. As the saying goes, "It is easy to go from frugality to luxury, but difficult to go from luxury to frugality", humans have no way to adapt to backward equipment. Now mobile phones are about to enter the 5G era, and AI is also quietly changing human life. All these cutting-edge and high-end technologies have chips at the bottom of their mechanisms.

In the 5G era, a large amount of data is generated every day. In order to process this explosive growth of data, chips need to have low power consumption, low latency, high computing power, and high bandwidth. Therefore, energy efficiency has become a key indicator for chip manufacturing today. How can these contradictory performances be achieved?

Chen Ping put forward the following thoughts:

1. If you want to improve technology, you must continue the development of Moore's Law

Chen Ping explained that the so-called Moore's Law is that when the price remains unchanged, the number of components that can be accommodated on an integrated circuit will double approximately every 18-24 months, and the performance will also double. This is actually a very radical theory, but from 3μm in 1987 to 7nm which has begun mass production today, everyone seems to have chosen to abide by and catch up with Moore's Law.

Transistor scaling continues

"As for TSMC, 7nm has been in mass production for more than a year, 5nm has entered the initial mass production stage, and will be put into mass production by the end of next year. 3nm is also on the way. It is worth mentioning that our 2nm research and development has also begun. We are constantly catching up with Moore's Law, it is still moving forward and has not failed," said Chen Ping.

What is the use of constantly improving and shrinking the process? Chen Ping gave such an example. As we all know, most of Huawei's current mobile phones use its own chips, and Huawei Mate 20 is one of the more popular mobile phones. This phone is equipped with the Huawei Kirin 980 chip. This chip integrates 6.9 billion transistors, has very powerful performance and extremely low power consumption, and all of this is achieved on a 7nm process.

The progress in process miniaturization has benefited from continuous innovation across the industry. The statement that Moore's Law has come to an end was mentioned as early as 1992, but it has continued over the years. It is too early to predict its decline, said Chen Ping.

For chip manufacturing, photolithography is a very important part. The development of photolithography was suspended for many years when it was 193nm, and finally achieved a breakthrough with immersion technology. The 7nm technology used today is achieved with 193nm photolithography. Today, photolithography equipment companies have made major breakthroughs. EUV technology has made photolithography no longer a bottleneck for miniaturization, and new materials have also made breakthroughs. This is why Chen Ping is confident that Moore's Law will not end.

2. Introducing a large number of 3D integration concepts

Although technology is constantly improving, there are more and more requirements for terminal products, requiring high-speed logic chips, memory, RF chips, etc. It is obviously not appropriate to spread them out on a plane as in the past. This means high chip power consumption and large area, which is completely opposite to the goal being pursued.

Therefore, Chen Ping proposed that the current method is to use semiconductor wafers to replace integrated circuit boards, wire the bottom, and connect different chips underneath. If the chips are placed in parallel, this method is called a 2.5D system, and if they are placed vertically, it is called a 3D system. TSMC has currently mass-produced 2.5D systems and is also developing 3D systems. In this direction, the development speed is parallel to Moore's Law.

3D integration technology improves vertical connection density

As an example, Chen Ping mentioned the CoWoS technology, which is a representative of the 2.5D system. It was originally abandoned by many companies due to its high price, but as the process advances to 16nm FinFET and the trend of heterogeneous chip integration takes shape, many manufacturers have placed orders. The 2.5D system can provide high-speed computing and is currently a more common technology.

Chen Ping also mentioned another trend - advanced packaging technology, which combines different processes through heterogeneous integration. Chips manufactured with completely different processes are combined together, which can not only preserve functions but also minimize size.

3. Co-optimization of hardware and software

For product production, hardware is important, but software cannot be ignored. Chen Ping said that in the early days of developing technology, mechanical methods were used, but now it is different. You need to see whether the final design is the most optimized solution. Therefore, it is necessary to work closely with customers during process development, and indicators cannot be the ultimate goal.

Synchronous software and hardware design improves energy efficiency

At the system level, the advantages of previous GPUs and CPUs are that they are more universal and programmable. But the disadvantages are also obvious, such as low efficiency, and the functions of hardware acceleration are specific and inflexible. The current design turns hardware accelerators into high-speed devices with programmable and designable functions, which is the general direction at the system level.

According to Chen Ping, the structure of future SoCs will basically be optimized by hardware and software, and TSMC will also pay close attention to the optimization of the system segment.

Finally, Chen Ping concluded that the demand of the semiconductor industry is very high, and now the requirements have changed from single type to comprehensive energy efficiency type. In order to make the entire system well, these three magic weapons are indispensable.