Smart devices are now indispensable tools in our daily lives. We use them for things like accessing the Internet and managing databases. ASAHI YUKIZAI resins are used in today’s constantly evolving IT devices as well.
Rediscover Resin as a Material for Electronics
Phenolic resins are used widely not only in today’s seemingly indispensable smartphones, but also in the manufacture of semiconductors, which play a central role as the "brains" of PCs and LCD TVs. We were the first company to establish a selective synthesis technology that can selectively synthesize phenolic derivatives*1 using ion exchange resins*2. This technology has won high praise in both industrial and academic circles. It has become one of our core technologies. We utilize it to manufacture phenolic derivatives (ballast material), the raw material for photoresists (photosensitive resins), which are essential for the formation of semiconductor circuits. In addition, we have also succeeded in developing high-purity phenolic resins, which are indispensable for photoresists. These resins are mainly used in the manufacturing of semiconductor integrated circuits, printed circuit boards, and flat panel displays, and as such are important materials for IT Society. We provide various phenolic derivatives and high-purity phenolic resins to match the needs of our customers.
*1 Resins with the ability to capture ions.
*2 Compounds controlled by molecular structures made from phenols.
Photoresists Vanish during the Manufacturing Process
Photolithography is a technique that applies the principles of photography. A semiconductor's electronic circuit is made by using this technique to imprint a microscopic circuit pattern. There are four processes in semiconductor manufacturing: 1) silicon wafer manufacture, 2) photomask manufacture, 3) wafer processing, and 4) assembly. A photoresist is a photosensitizing agent used in wafer processing to imprint a complex circuit pattern on a silicon chip that is only a few millimeters square. Phenolic derivatives and high-purity phenolic resins are used as the raw materials for photoresists. As you can see, the photoresist disappears during the manufacturing process and does not remain on the electronic circuit itself. However, it is an indispensable material in electronics manufacturing.
Silicon Wafer Processing
All semiconductors are manufactured through a combination of the following processes.
| Deposition: |
An insulating film of silicon dioxide is formed by heating the highly polished surface of a silicon wafer measuring approximately 0.5 mm thick. |
| Photoresist application: |
A spin coater rotates the silicon wafer as photoresist is applied to its surface by centrifugal force. A light is shone onto the silicon wafer through a glass substrate (photomask) bearing the electronic circuit pattern, exposing the photoresist only where the circuit pattern has been drawn.
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| Silicon wafer development: |
The silicon wafer is developed and the photoresist washed away from the exposed areas, revealing the silicon dioxide layer. |
| Etching: |
The revealed areas are then etched. The transfer of the image to the silicon wafer is complete after the remaining photoresist is removed. |
| Impurity doping: |
A diffusing agent is applied and the semiconductor region formed by heating at a high temperature. |
| Deposition: |
Once again, an insulating film of silicon dioxide is formed. |
Mutual Progress with the Electronics Industry
Photoresists continue to evolve too. The light wavelengths used are becoming shorter and shorter. Circuit miniaturization has progressed remarkably thanks to shorter wavelengths, making it possible to manufacture even more advanced electronic devices. Not so long ago, hard disks were rather large, but now they have been miniaturized down to just a few centimeters. The miniaturization of hard disks and advances in the field of resins are not unrelated phenomena. Recently, LCD screens are providing increasingly higher resolutions at ever-larger sizes. Higher performance photoresists are required in response to this trend towards larger sizes. A lot of strong light is needed to imprint a large area, so the sensitivity of the photoresist has to be boosted. Improvements in their respective technologies have led to mutual progress in the fields of electronics and resins. Phenolic resins have contributed greatly to the electronics industry, offering steady support from behind the scenes.
Thorough Quality Control and Original Technological Development
Roughly 10 ppm of metals such as iron are intermingled in standard resins, but the high-purity phenolic resins used in electronic materials are required to contain a maximum of 0.1 ppm. We have achieved a low level of metals through strict quality control that covers the entire process from manufacture to packing. We use glass-lined vats during the manufacturing process to prevent metal getting into the resin. We have very strict employee training in place, and control metal content at the ppb level (1 part per billion). In addition, we use original technologies we have developed to control alkaline lysis speed, molecular weight, and dispersity. We provide our customers with innovative ideas along with high-purity phenolic resins and phenolic derivatives that match their requirements.
