茫宇宙中，一个类金属合金宇宙探测器以超光速掠过，它由被强互作用力锁死的质子与中子构成，因表面绝对光滑而可以反射一切电磁波，并且无摧摧 ...... This is Liu Cixin in the sci-fi novel "Three Bodies" mentioned a kind of named "Water Drop" spacecraft. This is a cosmic vehicle called "water droplet" mentioned in Liu Cixin's science fiction novel "Three Bodies".
In fact, mankind's pursuit of "absolute smoothness" has also been transformed from science fiction into practice, such as the ultra-precision polishing technology that drove the "integrated circuit transformation revolution". Like the "three bodies" described in the same, the most advanced chemical mechanical polishing (chemical mechanical polishing, CMP) technology has entered the atomic size level. And while the electronics industry powers are scrambling to climb or reach the pinnacle of this process, we can only look up.
Modern electronics industry, ultra-precision polishing is the soul
Physical polishing is the most commonly used polishing technology before the 1980s, but the rapid development of the electronics industry on the size of the material device, the flatness of the increasingly demanding requirements. When a millimeter-thick substrate needs to be made into hundreds of thousands of layers of integrated circuits, the traditional old polishing process has been far from being able to meet the requirements.
Today's level of optoelectronic information industry, as optoelectronic substrate materials such as sapphire, monocrystalline silicon and other materials, the parallelism of the requirements of more and more precise, has reached the nanometer level. This means that the polishing process has also followed into the nanometer level of ultra-precision.
Ultra-precision polishing process in the modern manufacturing industry, how important, the application of the field can directly illustrate the problem: integrated circuit manufacturing, medical devices, automotive parts, digital accessories, precision molds, aerospace.
Wang Qi said: "Ultra-precision polishing technology in the modern electronics industry to complete the mission, not only to flatten different materials, but also to flatten the multilayer material, so that a few millimeters square silicon wafer through this 'global flattening' to form tens of thousands of million to millions of transistors consisting of Ultra-large scale integrated circuits. For example, the human invention of computers transformed from tens of tons to hundreds of grams now, without ultra-precision polishing can not, it is the soul of technology."
Core technology is hidden, domestic demand is restricted
Sun Ming said "pot" is the core device of the polishing machine - "grinding disk ". Ultra-precision polishing on the polishing machine in the grinding disk of the material composition and technical requirements are nearly harsh, this steel disk synthesized by special materials, not only to meet the automated operation of the nanometer precision, but also to have a precise coefficient of thermal expansion.
When the polishing machine is in high-speed operation, the flatness and parallelism of the substrate cannot be guaranteed if the thermal expansion causes thermal deformation of the grinding disk. The thermal deformation error that cannot be allowed to occur is not a few millimeters or micrometers, but several nanometers.
At present, the United States, Japan and other top international polishing process has been able to meet the 60-inch substrate raw materials for precision polishing requirements (belonging to the oversized), whereby they are in control of the ultra-precision polishing process of the core technology, firmly grasped the initiative of the global market. And in fact, grasp this technology, but also in a large degree of control of the development of the electronics manufacturing industry.
"In the face of such a tight technological blockade, we are very anxious, the Spring and Autumn period, Lu Ban invented stone grinding for mankind to help the farming civilization, and now our progress in the electronics industry is once again a kind of mill stuck in the neck. But again anxious, at present we have to wait, either waiting for imports, or independent research and development." Wang Qi said.
To reach the pinnacle of technology, it is better to ask for help
In fact, in the field of ultra-precision polishing, China is not without merit. As a set of technically demanding synthetic processes, the ultra-precision chemical mechanical polishing process must be composed of equipment and materials (polishing fluid), both of which are indispensable.
In 2011, Dr. Wang Qi's team developed the "cerium dioxide microsphere particle size standard material and its preparation technology" won the China Petroleum and Chemical Industry Federation of the first prize for technological invention, the relevant nanometer size standard material to obtain the National Measuring Instrument License and the national standard material certificate. The new cerium dioxide material of ultra-precision polishing production test effect in one fell swoop to catch up with the foreign traditional materials, to fill the gaps in the field.
But Wang Qi said: "This does not mean that we have climbed to the top of the field, for the overall process, only polishing fluid and no ultra-precision polishing machine, we are still at most just selling materials."
Sun Ming believes that a clear understanding of the specific requirements of the modern electronics industry production and manufacturing, in order to find the direction of the attack on the ultra-precision polishing process: "Polishing process needs to meet the current requirements of the electronics industry manufacturing can be summarized as ultra-precision, large size. With the top polishing materials is only the foundation, as a basis, we also need to be divided into two steps, first of all, to solve the problem of grinding disk, and secondly, to solve the problem of polishing area expansion."
Sun Ming introduced, the United States, Japan polishing machine grinding disk material composition and production process has been a mystery. In other words, the purchase and use of their products does not mean that you can imitate or even copy their products, which are two different things.
"What materials and processes can be used to synthesize this kind of low thermal expansion, high abrasion resistance, grinding surface ultra-precision grinding disc, is the first thing we need to focus on the technical challenges, this problem once solved, 60 inches of polishing work surface will also no longer be a dream. And such core technology, can never expect to get from others, in addition to relying on themselves, we have no choice." Sun Ming said.