April 17, 2007

SII NanoTechnology Releases SIR-7, a Photomask Defect Repair System for 45-nm Nodes

SII NanoTechnology Inc. has released the "SIR-7," a system that repairs defects on photomasks for semiconductor devices accommodating 45-nm nodes. This system is a next generation system offering the ease-of-use of the photomask defect repair system "SIR7000" for 65-nm nodes that was released in March 2005, while meeting the requirements of resolution, accuracy, and less damage that are needed for 45-nm node repair. The "SIR-7" model has been developed based on the technological accomplishments of the joint research that conducted in cooperation with Semiconductor Leading Edge Technologies (Selete) Inc., Dai Nippon Printing Co., Ltd., Toppan Printing Co., Ltd. and Hoya Corporation until March 2006.

The photomask is an original plate used in the lithography process for making semiconductor circuits. The photomask has emerged as a major factor in determining semiconductor element performance and production yield. In general, the following three technologies are critical to photomask production: (1) the technology used to form a pattern on a blank (a mask substrate covered with light shielding layers), (2) defect inspection technology used to detect whether the pattern has formed as indicated by data, (3) and defect repair technology used to repair a defective pattern. The defect repairs include clear defect repairs in which carbon is deposited in areas where some of the pattern is missing (clear defect1), and opaque defect repairs in which extraneous material that exists in a section where light is to be transmitted (opaque defect1) is removed by etching. The photomask defect repair system repairs both opaque and clear defects, thereby greatly improving the mask yield and making the system a piece of critical technology for mask production. With the 45-nm node generation of semiconductor devices, the size of defects requiring repair has become extremely small and complex in shape because of decreased line width and greater use of OPC patterns.2 Also, because of the use of 193-nm ArF lithography,3 the optical characteristics that the repair area needs to have have become extremely demanding, requiring a reduction in glass damage to a degree of several nm.

SIR-7 is a system that repairs microscopic defects using focused ion beams (FIBs). The system is capable of repairing microscopic opaque and clear defects of 45-nm node generation devices, to an accuracy of 4 nm or less (1 nm is one billionth of a meter), and of repairing defects based on high transmission with reduced glass damage.

SII NanoTechnology sold the world's first FIB-based photomask defect repair system in 1985, and maintains a high industry share both domestically and internationally. The new SIR-7 model is to be sold to photomask manufacturers both domestically and internationally.

Main Features of SIR-7

1. Repair accuracy of 4-nm or less (3ƒÐ) The new system features have improved repair accuracy, from the conventional 7 nm (3ƒÐ) to 4 nm (3ƒÐ). Adoption of low acceleration-type ion beam barrel allows high accuracy and low damage repair.

2. CAD linkage function By identifying the normal pattern of a defect area from the graphic data of EB4, used in semiconductor layout design, and superimposing the pattern on the defect area, the system enables repair based on a shape that is as close as possible to the normal pattern. The system also enables repair of complex shapes, such as OPC shapes, with higher fidelity.

3. SMIF transport mechanism The new model utilizes a photomask SMIF transport mechanism. The system can load a photomask carried by an SMIF pod5 into the chamber via a super clean load mechanism, preventing particles (microscopic contaminants) from adhering to the photomask.

Endnotes

1. Clear defect, opaque defect A "clear defect" refers to a transparent area where the pattern is missing, and a "opaque defect" refers to an opaque area where the pattern was unnecessarily applied.

2. OPC pattern An "OPC pattern" refers to a pattern based on optical proximity correction. This technology involves preliminary correction to a pattern on the photomask side to ensure that the pattern transferred after exposure will be the desired one.

3. ArF ArF (argon fluoride) excimer laser with a wavelength of 193 nm

4. EB An abbreviation of "electron beam." Here, EB refers to electron beam lithography equipment.

5. SMIF pod Mask storage box-like container. The SMIF pod is used to maintain a high degree of cleanliness inside the box-like container and prevent the adherence of particles (microscopic contaminants).