Large Size Photomask Substrates / Blanks Inspection System "LB79"

Lasertec has developed and commercialized a defect inspection system for large size substrates to be used for manufacturing of Photomasks that are indispensable for LCD panel production using G10 substrates. Because large size Photomasks are required to have no defects, very strict quality management is demanded for mask blanks and quart substrates that are base materials for Photomask production. Because LCD production utilizes 1X exposure method, mask size needs to become larger, from the viewpoint of productivity, as the mother glass substrate becomes larger. Furthermore, development of Photomask multi tone technology in the aim to shorten exposure processes is remarkably progressing and yield improvement and quality assurance are becoming very important tasks in the large size mask manufacturing processes.
The LB79 inspects large size substrates with high-speed and acquires distribution of defect positions and review images with accuracy and quickness. The LB79 presents highly reliable inspection by detecting, in addition to ordinary particles, defects that originate to process imperfection or material flow, which have been difficult to be inspected thus far.
The utilization of the LB79 for evaluation of polishing and after-cleaning processes leads to findings of problems and optimized conditions of processes at an early stage. Furthermore, the utilization of the LB79 for outgoing test should lead to yield improvement because defect detection will prevent run off of substrates with defects to the next process.
It is assumed that the LB79 is to be operated at development stage and for quality management of large size substrates, and moreover at substrate incoming inspection in mask maker factories. Referencing and verification of inspection result of Photomasks performed by the large size mask inspection system that is a de facto standard in the industry, with inspection result at incoming test of blanks, become available as very useful information for defect management. Simultaneous usage of the large mask substrates/blanks inspection system and the large size Photomask inspection system enables evaluation all through the manufacturing processes from material to final product in a comprehensive manner, which efficiently contributes to improvement of quality and yield.

• Differential interference optics makes nm order surface irregularity detectable.
  (detectable horizontal dimension is 1.0μm or larger)
  
• Laser scattering detection is installed and sensitivity for foreign particles is high (1.0μm).
  
• Verification of defect classification is performed based on input signal intensity from each sensor for differential interference, forward scattering and backward scattering.
  
• Tow sets of inspection head is installed to enable simultaneous inspection of front and back surfaces of a glass substrate.(The head for back surface inspection is optional)
  
• The system is compatible with substrate size up to 2.0 m x 2.0 m and speedily responds to the demand for inspection of substrates for large size Photomask of G10, the substrates being scheduled to be put into mass production in autumn 2008.
  
• Mechanism that moves head on a fixed mask substrate makes outer dimension and footprint compact.
  
• The system consistently performs from inspection to review with an easy-to-use and well-developed software.
  

1)Quality management of glass substrates after precision polishing and cleaning
2)Confirmation of substrate quality before and after layer formation
3)Incoming inspection of large size Photomask blanks

Please review "LB79"product page for any further information.