[ Custom UPS ] Semiconductor Wafer Inspection Machine

Annual Demand – A11J 5kVA & 10kVA/ 150 units

An e-beam inspection system is used to find small defects of a wafer with sensing technology of 3nm or lower. In an e-beam inspection system, the stage moves the wafer to a given location. Then, the electrons hit a small spot on the wafer. The image data is then collected on a pixel-by-pixel basis. The systems require a highly reliable power input. For this reason, SANUPS A11J was chosen to provide a reliable power supply and to maximize system performance. This particular wafer defect inspection system was shipped and used in clean rooms all over the world. Since the wafer is a thin slice of crystalline silicon used in electronics, the fabrication process requires a highly reliable power input supply. The customer previously experienced critical power failure with an uninterruptible power supply system from a different company.


EPO for Wafer Defect Inspection Machine

The Emergency Power Off (EPO) button, also called an EPO switch, is one of the most important safety measures for quickly disconnecting electrical power to a wafer defect inspection machine, or an entire facility, in the event of an emergency. The button allows all power, including Uninterruptable Power Supplies (UPSs) and batteries to be shut down safely from a central location.

However, the customer’s system and our UPS system had different logic programs for EPO since the customer used a different UPS system, and making changes on the customer’s application was not possible. We discovered that the EPO’s respond speed was not meeting the customer’s specification at the initial matching test.   


【Our Solution】
①Certification Challenge

Initially, this project was only for the U.S. market, but the customer expanded its business to Europe and Southeast Asia. Though many countries recognize and accept UL certification as a safety standard, Taiwan had different requirements.  In Taiwan, it is required to acquire the safety standard named BSMI (Bureau of Standards, Metrology, and Inspection). Also, SEMI (Semiconductor Equipment and Materials International) standard was required as all in one system with our Uninterruptible Power Supply.  

To obtain these safety standards, our code specialist checked all the documentation of BSMI and held technical meetings with the engineers. Our engineers redesigned an inverter circuit including components change and metal chassis design change enabling us to recertify UL 1778 standard. After many system evaluations and document submissions, we were able to obtain SEMI-S2, BSMI, and UL 1778 standard.


②Firmware Modification

For EPO (Emergency Power Off), we needed to modify the firmware to comply with the customer’s application. To do so, our engineers developed a reverse logic program within a short period of time. There was no need for changes in the customer’s application and the matching tests were successful.



Fig. EPO Diagram


③Different Design Concept

We designed our Uninterruptible Power Supply with safety in mind based on our long history of designing and creating power products.  One of the best examples of our product design is the EPO response speed. We designed the unit to stop 3 seconds after the EPO button is pressed. The reason behind these 3 seconds is the preventive measure in avoiding the wafer from becoming damaged on the inspection system causing monetary loss for businesses.  As a result, we created a system to shut down down the UPS right after the EPO button is pressed.



A11J is the SANUPS flagship model, and it is the most stable uninterruptible power supply system in the market because it provides a continuous pure sine wave using only fortified components based on advanced design and SANUPS technology. In addition with the SANUPS A11J, the battery pack or inverter maintenance is simple and easy to use. Therefore, e-beam manufacturers are able to reduce maintenance costs drastically.